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See detailCoupled Resonators for Ultraprecise Sensing Applications: Fabrication using State-of-the-art Laser Micromachining
Pachkawade, Vinayak ULiege

Doctoral thesis (in press)

This thesis documents a first time demonstration of electromechanical transducer and/or sensor fabricated using Direct Laser Writing (DLW). A low-cost prototype has been fabricated via a rapid and high ... [more ▼]

This thesis documents a first time demonstration of electromechanical transducer and/or sensor fabricated using Direct Laser Writing (DLW). A low-cost prototype has been fabricated via a rapid and high-tech laser micro-milling technique to achieve a parallel kerf-width (capacitive gaps) of about 60 micrometers (µm) into a piece of aluminum and a stainless steel each of 1 and 2 millimeters (mm) thickness respectively, thus leading to a high-aspect ratio (> 33) structure. A device is demonstrated to facilitate actuation via electrostatic means and sense a capacitive change across its electrode. Experiments have been performed with a structure made of aluminum. Emphasis is on the fabrication and associated issues. A strategic fabrication and measurement of an average kerf-width of about 60 micrometres is reported, which is advantageous to develop our application. A detailed study of width variation using laser cut is also given. Based on the in-depth literature survey, it is postulated that achieving simultaneously a kerf-width as small as 60 µm with metal parts up to 2 mm thickness is unprecedented (either in the industry or in academia). This important aspect is one of the highlights of this research. Results comprising analytical modeling, fabrication, and electrical characterization are presented. An applicability of a device as a 2 degree-of-freedom (DoF) resonating mode-localization sensor that employs a weak electrostatic coupling is demonstrated to offer vibration amplitude based sensitivity to a relative change in the stiffness. This sensor is able to resolve a minimum stiffness perturbation (normalized), of the order of 7.98×10-4. This magnitude is of the same order to that achievable in MEMS based coupled resonators. Based on our results, it is postulated that this navigating research opens up new possibilities to fabricate new devices and/or sensor based on alternative fabrication platform such as laser micromachining as reported here. In parallel, a work in this thesis closely observes the state-of-the art for coupled resonators and thereby proposes realistic system level models in the context of our architecture fabricated using high-tech laser machining. Based on the representative system-level models developed in this thesis, theory estimate of maximum sensitivity to stiffness perturbation is found to be comparable to that achievable in MEMS for two degree of freedom (DoF) coupled resonating sensor. Developed models represents findings in open/closed loop implementation. A work on the most fundamental and crucial aspects such as sensitivity, resolution and noise floor of coupled resonators is reported. [less ▲]

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See detailHafting as a flexible strategy: variability in stone tool use and hafting at three European Upper Palaeolithic sites
Taipale, Noora ULiege

Doctoral thesis (in press)

Despite the central role of technology in recent archaeological debates, and the assumptions of the superiority of Upper Palaeolithic technologies over older ones, very little is actually known of stone ... [more ▼]

Despite the central role of technology in recent archaeological debates, and the assumptions of the superiority of Upper Palaeolithic technologies over older ones, very little is actually known of stone tool hafting and overall tool design during this period. This study uses recently developed microscopic methods for identifying hafting to directly address the question of tool design and its links to tool use and general technological strategies in the Upper Palaeolithic of Western and Central Europe. Framed in the context of a larger project that looks at long-term technological change from the Middle Palaeolithic to the Upper Palaeolithic, this work involved a detailed analysis of c. 1100 lithic tools from the Gravettian occupation layers of Abri Pataud and Maisières-Canal and the Gravettian and Magdalenian layers of Hohle Fels. The work takes particular interest in domestic tools that remain understudied and yet are necessary for understanding the development of technical systems as a whole. In addition, projectile material from Abri Pataud was analysed in order to reconstruct Recent Gravettian and Final Gravettian weapon design. The results show that there was no simple linear increase in stone tool hafting over time. Instead, it was a strategy that was applied flexibly and selectively according to task requirements and constraints, raw material situation, and other circumstances. It therefore needs to be viewed in the context of e.g. raw material economy, mobility patterns, and social organisation including the division of labour. [less ▲]

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See detailRéfugiés kurdes de Turquie dans l'Ouest de la France et en Belgique de 1977 à nos jours
Rondeau, Coline ULiege

Doctoral thesis (2020)

Les "carrières migratoires" des Kurdes dans l'Ouest de la France et en Belgique - et plus particulièrement des demandeurs d'asile kurdes - constituent le point de départ de cette étude. Entrés dans le ... [more ▼]

Les "carrières migratoires" des Kurdes dans l'Ouest de la France et en Belgique - et plus particulièrement des demandeurs d'asile kurdes - constituent le point de départ de cette étude. Entrés dans le cadre de l'asile, les Kurdes se sont présentés et se sont racontés. Leurs récits de vie sont le fruit d'une construction sociale opposant le "qui suis-je ?" au "que suis-je ?" voire même "que dois-je être ?". Parallèlement, les décisions de rejet formulées par les institutions de l'asile ont - à la fois - dissocié et associé les Kurdes à des groupes d'appartenance. Face à l'intensité progressive du doute, les Kurdes ont utilisé de nombreuses stratégies de visibilisation et/ou d'invisibilisation lors de procédures diverses. Dans une approche croisée, les conditions de vie et les circulations des Kurdes en Turquie puis vers l'Europe apportent des éléments de réponse sur les routes migratoires empruntées, les transports utilisés. Les Kurdes se sont installés dans de nouveaux espaces nécessitant des réseaux pluriels et des solidarités multiples. Les recompositions territoriales entre les différentes générations de Kurdes se conjuguent à la création d'associations déplaçant le conflit turco-kurde en raison d'appartenances politiques plurielles et montrant la nécessité de transmettre une voire des mémoires. [less ▲]

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See detailReduced-order modelling of active distribution networks for large-disturbance simulations
Chaspierre, Gilles ULiege

Doctoral thesis (2020)

Distribution systems are getting more and more complex owing to the increasing number of Inverter-Based Generators (IBGs) connected at Medium-Voltage (MV) level. This makes distribution networks more and ... [more ▼]

Distribution systems are getting more and more complex owing to the increasing number of Inverter-Based Generators (IBGs) connected at Medium-Voltage (MV) level. This makes distribution networks more and more responsive and their influence on the whole power system dynamics increases. Therefore, it becomes important for Transmission System Operators (TSOs) to model those Active Distribution Networks (ADNs) in their dynamic studies. First, this thesis deals with the derivation of reduced-order, “grey-box” models of ADNs, intended for dynamic simulations of the transmission system. The ADNs are assumed to host IBGs as well as static and motor loads, whose dynamic parameters are affected by uncertainty. This latter issue is addressed using Monte-Carlo simulations. The parameters of the equivalents are adjusted to match as closely as possible the average of the randomized responses, while their dispersion is accounted for through the weights of the weighted least-square minimization. A procedure is used to remove from the identification the parameters with negligible impact. To avoid over-fitting, the equivalents are tuned for multiple large-disturbance simulations. A recursive procedure is used to select the smallest possible subset of disturbances involved in the least-square minimization. Next, the methodology is extended to account for changing operating conditions. This consists of testing the accuracy of a set of previously derived equivalents, and updating the best of them if its accuracy is not satisfactory. In order to update the equivalent with minimal effort, an approach minimizes the number of parameters to update. In most cases, the results coincide with expectations coming from “engineering judgment”, involving the adjustment of a (very) small subset of parameters. Finally, a new application for a Battery Energy Storage System (BESS), connected at distribution level, is proposed. Its active and reactive powers are controlled such that the net power entering the distribution network matches the response of the available equivalent to large disturbances in the transmission system. The response of the equivalent is simulated in real time. This would allow using with a higher guarantee of accuracy the equivalent model in dynamic simulations of the transmission system. The BESS is supposed to be connected at the main substation of the distribution grid and its control does not use any model of that grid. All simulations reported in the thesis have been carried out on three ADN test systems with different characteristics, one of them being derived from an existing distribution grid. The tests involve large disturbance scenarios that trigger nonlinear, discontinuous responses of IBGs and loads. [less ▲]

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See detailNew ways of working, new ways of living...What housing and planning implications? Ontologies and governance of live-work mix. A comparison of Amsterdam, Brussels and Stockholm
Uyttebrouck, Constance ULiege

Doctoral thesis (2020)

The ‘flexibilisation’ of labour markets has led to the blurring of the work and home spheres, which has had implications on housing and planning. This thesis addresses the ‘live-work mix’, that is, the ... [more ▼]

The ‘flexibilisation’ of labour markets has led to the blurring of the work and home spheres, which has had implications on housing and planning. This thesis addresses the ‘live-work mix’, that is, the renewed intertwining of living and working activities in new housing production and urban development. This phenomenon is related to the focus on new target groups, the restructuring of housing provision and changes in urban agendas. Three research questions are addressed in this research: (i) what are the different ontologies of live-work mix in contrasting institutional frameworks, (ii) what kind of governance arrangements are used to implement live-work mix and (iii) how do institutional frameworks influence the nature and governance of live-work mix. An embedded, comparative case-study analysis was conducted to tackle these questions, with three cities as main cases (Amsterdam, Brussels and Stockholm) and a typology of live-work mix as embedded cases. The analytical framework draws on path dependency and an institutionalist approach to collaborative governance. The first part of the thesis compares the housing and planning regimes as well as live-work mix strategies of the case-study cities. The analysis confirms the impact of early planning directions and shows how factors such as historically dominant actors impact local ontologies of live-work mix. Nevertheless, current issues conditioning live-work mix, such as the flexibilisation of tenure, apply across contexts. The governance of live-work mix is explored in the second part. The results indicate that local governments’ intervention is essential in live-work development, whereas market parties remain focused on residential development. Live-work mix also requires new instruments and strategic uses of existing tools. Although the actors share interests to enhance the attractiveness of a specific location for target demographics, their collaboration can be affected by divergent views, for instance, about the nature of live-work mix. As a result, the projects delivered are likely to favour housing, and affordability and accessibility issues can arise. A comprehensive discussion reconnects the empirical findings to the conceptual framework. It confirms that live-work mix is purposed for specific groups and draws on the emergence of new (commodified) housing forms in locations prioritised in urban agendas. Although institutional frameworks affect several variables of live-work mix, the implementation of live-work goals is not always more effective in more regulated frameworks. The discussion closes with suggestions for the regulation and governance of live-work mix that will inform planners and decision-makers on a phenomenon that is likely to expand in the future. [less ▲]

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See detailGypsum residues in fine recycled aggregates: effects on mechanical and microstructural properties of cementitious composites
Colman, Charlotte ULiege

Doctoral thesis (2020)

Fine recycled aggregates are an important waste stream coming from the demolition of old concrete structures. They are up to now not valorized because of an increased water absorption, lower density and ... [more ▼]

Fine recycled aggregates are an important waste stream coming from the demolition of old concrete structures. They are up to now not valorized because of an increased water absorption, lower density and higher fines content compared to natural aggregates. Moreover, they often have a high sulfate concentration. These sulfates could have originated from plaster in a demolished building, or from the residual cement that is commonly present in these materials. The sulfate level of recycled aggregates is recommended to stay under 0.2 mass% by standard EN206, to limit the risk on sulfate attack: the reaction between cement components, water and sulfates results in the formation of expansive minerals such as ettringite. This expansion can eventually lead to cracking of the material and a general loss in mechanical performances. Fine recycled aggregates from recycling plants did contain 0.15 to 0.80 % of sulfates which is more than allowed, but these amounts did not cause any swelling or degradation when the aggregates were incorporated into mortars. A very elevated sulfate content of 3 % was needed to observe significant expansion, and even this level of contamination could be mitigated by increasing the alkalinity of a mix. Concretes made with varying sulfate levels either expanded or they didn’t: the absolute swelling amount was not proportional to its sulfate content. The actual threshold concentration that started the swelling reaction was dependant on the type of coarse aggregate. The results of this study provide recommendations for the use of fine recycled aggregates contaminated with gypsum residues: a sulfate content of at least 0.3 % could be possible, and even more if certain parameters and mix compositions can be adjusted accordingly. The current limit of 0.2 % seems too strict and hinders the valorization of fine recycled aggregates in high quality construction applications. [less ▲]

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See detailAutofabuladores fabulosos. Estudios sobre las autoficciones no miméticas de Mario Bellatin, Alan Pauls, Valeria Luiselli y César Aira
Licata, Nicolas ULiege

Doctoral thesis (2020)

The title of this dissertation, which holds a descriptive value of its content, is a good starting point for its summary. The word “autofabulator” refers to the author of an “autofabulation”, a technical ... [more ▼]

The title of this dissertation, which holds a descriptive value of its content, is a good starting point for its summary. The word “autofabulator” refers to the author of an “autofabulation”, a technical term that in turn refers to an obviously imaginary type of narrative that a writer builds around his or her own person, playing in it a more or less leading role. “Autofabulators” is reinforced by the adjective “fabulous”, which should be understood in the sense of “unreal”, “extraordinary”, “implausible”, because the authors considered here are not moderate fabulators. On the contrary, the plots they imagine are resolutely fictitious, and their narratives bring out this fictitious nature in many ways. In the subtitle, the expression “non-mimetic autofictions” is used as a synonym for the word “autofabulation”, and I speak of “studies” in the plural (and not of “a study” in the singular) because each chapter focuses on only one of the four authors cited, giving the priority to the unicity of his or her work. That being said, the fact that each chapter offers a reading of an individual work does not preclude that it also builds bridges with the three other authors’ work, in order to elucidate one or various important aspects of autofabulation and/or autofiction in general. It is therefore recommended to read these chapters conjointly. From the subtitle, it can be deduced that this doctoral thesis does not aim at providing a panoramic study of autofabulation, one that would be based on a large number of its cultivators. This does not however mean that I have completely lost sight in my methodology of the variety that characterises the panorama. Instead of opting for a panoramic thesis, that would encompass a wide range of authors, I opted for integrating the panorama in my approach to the narratives: not a panoramic point of view, but a panorama of analytical points of view. Indeed, remaining always primarily literary, my approach to Mario Bellatin’s (Mexico City 1960), Alan Pauls’ (Buenos Aires 1959), Valeria Luiselli’s (Mexico City 1983) and César Aira’s (Coronel Pringles, province of Buenos Aires 1949) autofabulations renews itself from chapter to chapter, and often even from subchapter to subchapter. In the pages of this thesis, the following issues among others are dealt with: the critical relationship of autofiction with medicine and more globally with sciences, feminine autofiction, the similitudes between contemporary Hispano-American autofabulation and the French nouvelle autobiographie, the rhizomatic conception of identity developed in autofabulation, the social image that autofabulators create of themselves, the ludic reading pact they propose to their readers, as well as the openness of their narratives as defined by Umberto Eco. [less ▲]

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See detailSteady Transonic Aerodynamic and Aeroelastic Modeling for Preliminary Aircraft Design
Crovato, Adrien ULiege

Doctoral thesis (2020)

Modern aircraft usually have light and flexible wings with large aspect ratio, which are subjected to significant deformations. The aeroelastic behavior of such wings is of paramount importance as it ... [more ▼]

Modern aircraft usually have light and flexible wings with large aspect ratio, which are subjected to significant deformations. The aeroelastic behavior of such wings is of paramount importance as it affects both the structural design and the aircraft performance. The present thesis aims at assessing the impact of aerodynamic modeling on transonic aerodynamic and aeroelastic com- putations performed in the preliminary stage of the aircraft design process, and at developing an aerodynamic modeling tool performing such computations with low computational cost. First, the different levels of fidelity commonly used for aerodynamic modeling in aircraft design are investigated. The aerodynamic loads predicted by the different models and the compu- tational cost of the solutions are compared using two rigid wings simulated in transonic flight conditions. The results show that linear modeling is not suitable for transonic flow calculations as it cannot capture shocks, and that higher-fidelity models are too computationally expensive to be used routinely in the preliminary design stage. On the other hand, nonlinear potential solutions offer an excellent trade-off between accuracy and computational cost. Accordingly, the main full potential formulations and their solution techniques are subsequently reviewed. Two specific methods for solving the full potential equation are then developed and imple- mented. The first is the field panel method, an extension to the widely used and computationally effective panel method. Numerical calculations show that the iterative field panel approach im- plemented during this work yields satisfactory results for subcritical flows, but smears shock waves and thus cannot model transonic flows accurately. Moreover, the computational cost of the method is prohibitive for such computations. The second method is based on a continuous Galerkin, unstructured, finite element formulation. The code developed in the context of this work, Flow, is compared to a commercial state-of-the-art solver, Tranair, using various two and three-dimensional cases. In practice, Flow is as fast and almost as accurate as Tranair, but is open-source. The modular design of Flow allows the code to be easily coupled with CUPyDO, an in-house fluid-structure interaction code, which is then used to perform static transonic aeroelastic com- putations. In this context, the different aerodynamic levels of fidelity are compared using a flexible benchmark wing. For the wing shape considered in the present work, the results illus- trate that linear potential methods yield sufficiently reliable static deformations, provided they model wing camber. On the other hand, nonlinear methods yield more accurate aerodynamic predictions but their computational cost is significantly higher. Consequently, static aeroelastic computations could be efficiently performed following a multi-fidelity approach, whereby a lin- ear model would first be used to obtain the deformed wing shape, and a nonlinear model would then be used to compute the aerodynamic loads on that deformed wing shape. [less ▲]

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See detailEngaging in homeland politics from abroad: processes of subjectivation and transnational mobilisation
Lara Guerrero, Larisa Viridiana ULiege

Doctoral thesis (2020)

Migrant populations have the power to engage in homeland politics once they leave their country of origin through transnational campaigns, extraterritorial voting, advocacy efforts, protests, and even ... [more ▼]

Migrant populations have the power to engage in homeland politics once they leave their country of origin through transnational campaigns, extraterritorial voting, advocacy efforts, protests, and even artistic performances. This dissertation presents ethnographic material collected among the Mexican community in Brussels and Paris between 2014 and 2018 to answer to the following research question: How do Mexican migrants in Europe engage in homeland politics? By looking at how Mexican migrants engage in homeland politics, this research posits three main arguments. First, it places migrants at the forefront of the analysis. Migrants are recognised as the individuals (with cognitive and emotional dimensions) who decide how and when to engage in homeland politics from abroad. Second, it is contended that migrants’ motivations and decisions to engage in homeland politics rely on their individual processes of subjectivation. Through these processes, migrants can reflect upon their life experiences, determine their own political identity, and thus develop their own original strategies of transnational political participation. Finally, it is argued that migrants are embedded and operate in four social spaces: the homeland, the hostland, the diaspora and the global. These spaces not only influence migrants’ decision to engage in transnational politics, but they also determine their strategies. Indeed, it is argued that migrants are individuals who can only engage in transnational politics once they adapt to the norms, create alliances with key actors, and find resources embedded and governing each of these four social spaces. In short, migrants become political subjects with the power to use the norms, interact with actors, and exploit resources available in the hostland, homeland, diaspora, and global political spheres to achieve their political goals. [less ▲]

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See detailInteractions trophiques Hémiptères – plantes-hôtes : Etude des stratégies de contournement des défenses végétales induites
Serteyn, Laurent ULiege

Doctoral thesis (2020)

Along this thesis, we investigate phytophagous insects of the piercing-sucking guild, belonging to the Hemiptera Order. In the state of the art, we identify two key-elements of their strategies to ... [more ▼]

Along this thesis, we investigate phytophagous insects of the piercing-sucking guild, belonging to the Hemiptera Order. In the state of the art, we identify two key-elements of their strategies to counteract plant defenses, at the plant-insect interface: feeding behavior and salivary proteins. In such context, we notice several gaps in the knowledge of Pentatomidae, and more largely of Heteroptera: variable feeding behavior, lack of studies on salivary compounds and unclear plant-insect interactions. Moreover, many studies pointed out the influence of microbial agents on plant-insect interactions, which complexify greatly the conclusions. The aim is to enlighten the roles of feeding behavior and salivary proteins in the counteraction of induced plant defenses, taking into account four trophic levels: the rhizobacteria Bacillus velezensis FZB42 as an inducer of plant defense priming, the plant Vicia faba L., the Hemipteran insects, the brown marmorated stink bug (BMSB) Halyomorpha halys (Stål) and the pea aphid Acyrthosiphon pisum (Harris), and the endosymbiont Hamiltonella defensa. As preliminaries, we detail the feeding behavior of the stink bug H. halys by electropenetrography (EPG), providing a first EPG waveforms library for this invasive pest. We also set up a protocol to extract its salivary proteins, preceding a sensitive analysis of salivary proteome by mass spectrometry. We then applied these methods to evaluate the perturbation of feeding behavior and salivary proteins following the exposure to insect-induced plant defenses. First, the feeding behavior is perturbed when insects feed on these elicited plants. Second, proteomics on stink bug’s saliva highlight an up-regulation of proteins potentially involved in plant-insect interactions, including the detoxification of plant defense metabolites, following a short exposure to elicited plants. In the next chapter, we focus on BMSB salivary proteome, as a key-strategy to counteract plant defenses. We aim to identify the qualitative and quantitative changes in salivary proteins of insects exposed to the priming of plant defenses provoked by a third agent, the rhizobacterium B. velezensis FZB42. And indeed, BMSB saliva includes, once more, up-regulated proteins potentially involved in plant defense deactivation, following a short exposure to inoculated plants. In the last experimental chapter, we work on two genotypes of the pea aphid A. pisum, differing by the presence of the symbiont H. defensa. We analyse the defense pathways induced by B. velezensis FZB42 and we quantify the development and the feeding behavior of aphids exposed to the defenses. As a matter of fact, bacteria associated with the aphid add a greater complexity to the interpretation of observed phenomena. Such quadripartite interactions deserve more studies in order to better understand the actual role played by endosymbionts and/or the genotype in the counteraction of induced plant defenses. [less ▲]

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See detailSur les traces de l'armement préhistorique: Mise au point d'une méthode pour reconstruire les modes d'emmanchement et de propulsion des armatures lithiques par une approche expérimentale, mécanique et balistique
Coppe, Justin ULiege

Doctoral thesis (2020)

The identification of Palaeolithic weapon systems has long posed a challenge to prehistoric archaeology. The use of certain modes of propulsion, particularly long-range weaponry, is currently being argued ... [more ▼]

The identification of Palaeolithic weapon systems has long posed a challenge to prehistoric archaeology. The use of certain modes of propulsion, particularly long-range weaponry, is currently being argued for increasingly old archaeological contexts. The use of these weapons is often considered one of the key elements for understanding Palaeolithic subsistence strategies. Nevertheless, despite numerous efforts, no reliable method has yet been developed that would allow distinguishing between different modes of propulsion on the basis of lithic points once hafted as weapon armatures. Our work focuses on this objective: the development of a method that permits the identification of propulsion modes on the basis of use-related traces preserved on lithic projectiles. This study is one of the methodological components of a broader research project that investigates the appearance, variability, and change in hafting technologies through the Middle Palaeolithic and the Upper Palaeolithic by means of lithic functional analysis. We began by a critical overview of traditionally used approaches, both those focused on the identification of lithic projectiles in archaeological contexts and those dedicated to the reconstruction of the weapons with which these points were associated. This allowed us to draw attention to certain shortcomings in the identification of projectile elements and to the considerable unreliability of the methods currently used in reconstructing modes of propulsion. We have addressed this problem by proposing a new approach. It builds, on the one hand, on work done on fracture mechanics of brittle solids in the context of developing technological and functional analyses of stone tools and, on the other, on ballistic analysis of different modes of propulsion that could have been used in the Palaeolithic. These two elements are closely intertwined in our approach. The experimental program focused on ballistics permitted us to isolate two key parameters, namely the angle of incidence and kinetic energy. These affect the mechanical stress created on impact that is particular to each mode of propulsion. We subsequently carried out a large-scale experiment to test the interactions between these different stress situations and varied point morphologies as well as bonding techniques of varying resistance to evaluate the combined effect on impact fracture formation. As a whole this work allowed us to develop a five-step approach based on the characterisation of mechanical impact stress suffered by a collection of experimental points. The procedure was then successfully tested through the analysis of two Gravettian point assemblages from Maisières-Canal and Ormesson les Bossats. The results, supported by experiments tailored according to site-specific parameters, allowed us to propose two reasonable hypotheses concerning the weaponry associated with these archaeological contexts. For Maisières-Canal, spearthrower could be identified as the mode of propulsion associated with tanged points, and for Ormesson, oblique distal hafting of microgravette points could be argued to be at least one of the hafting systems employed at the site. These archaeological case studies also highlighted the significant experimental effort needed for obtaining these kinds of results. [less ▲]

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See detailLe financement public des arts de la scène en Belgique, en France et aux États-Unis : Aspects juridiques
Vandenbulke, Antoine ULiege

Doctoral thesis (2020)

The thesis consists in an analytical and critical study of the legal regimes of performing arts funding in Belgian, French and US federal law. Due to the economic difficulties encountered by the operators ... [more ▼]

The thesis consists in an analytical and critical study of the legal regimes of performing arts funding in Belgian, French and US federal law. Due to the economic difficulties encountered by the operators of the sector and to the political will to support such an activity of general interest, different legal financing schemes have been put in place in the three systems studied. More specifically, the public authorities intervene both directly (by granting subsidies or various forms of aid and by setting up a social regime favourable to performing arts workers in Belgium and in France) and indirectly (by means of tax expenditures, in order to stimulate private investment and patronage, encourage consumption, or reduce the costs borne by cultural operators). The aim of the thesis is to draw up an exhaustive overview of the relevant legal mechanisms within these three legal orders and, on this basis, to detect the existence (or not) of a certain model of public financing of the performing arts sector. In particular, the aim is to determine whether the differences between a continental approach, a priori more favourable to direct public intervention, and an American approach, more inclined to encourage private funding, are also reflected into the legal mechanisms studied. [less ▲]

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See detailOptimization of phenolic compounds extraction from Tetrapleura tetraptera and Aframomum citratum and biological assessments
Eyenga, Manga ULiege

Doctoral thesis (2020)

This thesis explores the optimization of phenolic compounds extraction and the biological activities of two non woody forest products (Tetrapleura tetraptera and Aframomum citratum fruit extracts) spread ... [more ▼]

This thesis explores the optimization of phenolic compounds extraction and the biological activities of two non woody forest products (Tetrapleura tetraptera and Aframomum citratum fruit extracts) spread in three agro-ecologic zones in Cameroon in a home food consumption context. The fruits are used for seasoning traditional recipes and in the traditional pharmacopeae. The general objective of this study was to contribute to a development of a therapeutic and preventive dietary supplement rich in dietary antioxidant to fight against oxidative stress on diabetic patents. As they are geographically harvested in many agro-ecologic areas, the various specific objectives were to investigate on their chemical and biological variabilities; on the impact of heat treatment (roasting) on their properties; to define the optimum conditions for total polyphenol recovery of a mix of the spices; and to administer a beverage obtained under optimum extraction conditions to diabetic rats in other to study their antidiabetic capabilities. The first trials results showed that for T. tetraptera, samples from the bimodal forest zone (BFZ) possess more sugars, calories, minerals and phenolic compounds. Gallic acid, chlorogenic acid, benzoic acid, 2-OH cinnamic acid, salycilic acid, flavone, gallocatechin, epigallocatechin gallate, naringin, phlorizin were among the predominant phenolic compounds identified in aqueous extract. Concerning A. citratum, samples from the BFZ contain more protein, fiber, phenolic and minerals (especially samples from the East region). A total of six dominant phenolic acids (Gallic, chlorogenic, protocatechuic, 2-OH cinnamic, caffeic, p-coumaric) and five flavonoids (epigallocatechin gallate, resveratrol, phlorizin, rutin, epicatechin, luteolin) were observed on the extracts. All the aqueous extracts biological activities (antioxidant, anti-inflammatory) of spices from the BFZ are dose dependent and more effective. Heat treatment significantly reduces fat, raw proteins and total sugars but improves raw fibre, phenolic contents and the biological activities of all the spices. For the total polyphenols recovery, the optimal conditions were: roasting temperature of 150°C, roasting time of 12.6 min, a brewing time of 11.9 min. After in vivo test on rats, the effect of the beverage alone is significantly the same as the conjoined administration of the beverage and the antidiabetic drug (Glibenclamide) reference and the administration the α-glucosidase inhibitor (Acarbose) after 4hrs when assessing the anti-hyperglycemic test on diabetic rats. The Glibenclamide effect is significantly improved by the beverage administration on hypoglycaemic assay and this synergy reduces diabetes complications on diabetic rats. As conclusion, the best areas to harvest are in the BFZ and the heat treatment applied has to be controlled. The beverage obtained with 95/5 Tetrapleura tetraptera/Aframomum citratum formulation possesses antoxidant, anti-nflammatory and hypoglycaemic activities. However there is a need for additional in vivo tests in order to confirm the different in vitro biological activities observed and to determine the human relevance of the beverage at the dose used. [less ▲]

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See detailApple microbiome-based improvement of biocontrol agents for postharvest pathogens management
Sare, Abdoul Razack ULiege

Doctoral thesis (2020)

Biocontrol using biocontrol agents (BCA) is a sustainable way to manage postharvest diseases. Nevertheless, their reliability (stability of efficacy) must still be improved to reach efficacy of synthetic ... [more ▼]

Biocontrol using biocontrol agents (BCA) is a sustainable way to manage postharvest diseases. Nevertheless, their reliability (stability of efficacy) must still be improved to reach efficacy of synthetic chemical pesticides. Indeed, when BCA are applied on the plant surface, they meet contrasted microbial community in which ecological relationships take place, thus potentially interfering with their efficacy and stability. Understanding better the role of fruit microbiota composition in the disease development and in the efficacy of BCA is an emerging research area. This could allow the isolation of more beneficial strains or the identification of molecules that modulate host microbiota to favour BCA and to limit disease development. In this thesis, apple microbiota was deeply characterized and used in situ to improve the efficacy and stability of Pichia anomala strain K, a BCA against Botrytis cinerea rot. At first, several protocols to harvest the epiphytic microbiota were tested and compared. Results showed that a first wash harvested one third of culturable microorganisms, and that three successive washes harvested around 80% of them. There were significant differences between protocols, thus inducing potential bias among studies using different protocols to study the epiphytic microbiota. However, this bias was offset by pooling the successive washes, that besides increased overall microbial richness. Then, the metagenome of apple fruit microbiota was studied by shotgun highthroughput sequencing (HTS) on three symptomless samples of apple fruit Pinova variety. Results showed a very high fungal (79.0 %) and bacterial (13.8 %) diversity. The prevalent phyla were Ascomycota for fungi and Bacteroides for bacteria. Genera of known apple postharvest pathogens and known BCA were identified. The functional analysis showed important genes potentially involved in biocontrol activity. On the other hand, the incompleteness of current databases and the complexity of the analysis limited the complete exploitation of the results and are blockages of using such technic currently. Finally, contrasted apple microbiomes were harvested and studied to identify beneficial strains and molecules to control Botrytis cinerea. Eighteen apple microbial communities (representing fifteen cultivars and four management practices) were harvested and characterized by HTS of 16s rRNA gene and Internal Transcript Spacer (ITS) amplicons. The biocontrol efficacy against B. cinerea of these microbiotas applied alone or with a BCA was also evaluated and the metabolisation of 190 carbon sources was studied. Results showed that apple microbiota is diversified and contrasted at taxonomic level, biocontrol efficacy and carbon source metabolisation. Certain microbiota significantly raised the strain K efficacy up to 100%. The alpha diversity of the apple microbiota was not correlated to the biocontrol efficacy. Coclustering of Spearman correlations were used to drive the isolation of promising beneficial strains (BCA candidates or helper strains supporting BCA efficacy) and molecules allowing better control of the pathogen. Biocontrol efficacy of the new strains and molecules was further confirmed in vivo. Results of this work can contribute to increase the reliability of BCA in real condition. [less ▲]

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See detailFrom "Coal to Gas" to "Coal to Biomass": Sustainable Development Path for Coupling Rural Energy Improvement and Straw Utilization in China
Wang, Qiang ULiege

Doctoral thesis (2020)

Currently, the Chinese government is promoting the diversification of energy sources in rural areas to reduce the consumption of coal. The development of biomass resources in agricultural areas is an ... [more ▼]

Currently, the Chinese government is promoting the diversification of energy sources in rural areas to reduce the consumption of coal. The development of biomass resources in agricultural areas is an alternative means of energy supply. This thesis assesses the potential offered by the centralized biogas production and straw briquetting fuel. Firstly, the environmental and economic performances of these two methods are assessed through an emergy analysis for two cases. The results show that, while the two projects studied have a high reproducibility and a low environmental load, the indicators of long-term sustainability are not favorable, in particular, in the event of a marked deficit in demand on the biogas or briquetting fuel. However, since the indicators of sustainability and economic profitability improve when the load tends towards the maximum capacity of the productions, the two models studied exist optimization margins. In the second step, the positioning of consumers relatively one of the two aforementioned markets, namely that of biogas, was explored by the method of contingent valuation method (CVM). This made it possible to estimate the rural residents’ willingness to use (WTU) and the willingness to buy (WTB) for this renewable energy source and to identify the determinants factors of these willingnesses. The results show that, although most of the respondents support the product, there is a significant gap between the amount of WTB and the costs of producing biogas. The propensity of potential consumers to use biogas and the amount of WTB depend not only on their personal and family characteristics but also on some non-economic factors, such as their level of knowledge on environmental issues, their attitudes, and practices regarding energy consumption. Consequently, it is recommended to reinforce awareness campaigns in order to improve the level of knowledge, influence the attitude of rural residents with regard to environmental issues, guide their practices in terms of the use of clean energy. Understanding the factors that influence demand has also made it possible to offer a suitable financial support mechanism capable of supporting market development. The third part of this thesis deals with the question of financing such projects. The public–private partnership (PPP) model is seen as a response that can mobilize social capital to finance investments in these new modes of production and energy supply in rural areas. Based on an analysis of the strengths, weaknesses, opportunities, and threats (SWOT) of the two projects considered above, an analytic hierarchy process (AHP) was carried out with the assistance of experts in order to clarify the strategic choices which are more suitable for investors. The strategic decision model identifies that a pioneering strategy based on opportunities is promising for the straw briquetting fuel project, while an aggressive type strategy in struggling strategy is essential for the centralized biogas production project. In order to encourage investors to adopt a positive and optimistic attitude towards the two projects, the public authorities have a role of guidance to ensure the mobilization of the social capital necessary for the construction of the projects. Finally, the results of the research recommend the implementation of a safeguarding strategy to promote the two modes. The first is to strengthen the capacity to design adequate guidance and support policies. Second, efforts must be made to innovate and promote technologies and business models in order to quickly remove barriers to their adoption. Third, improvements must be made in terms of financial incentives to increase the effectiveness of support funds. Fourth, stakeholder participation in the service structure must be established in order to clarify the responsibility of each role. [less ▲]

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See detailThe complex impact of temperature and carbon dioxide concentration on a multitrophic interaction involving aphids
Blanchard, Solène ULiege

Doctoral thesis (2020)

Global warming is now widely recognized in the scientific community. These changes are mainly caused by the increase of greenhouse gases, among which the carbon dioxide (CO2) is considered as a major gas ... [more ▼]

Global warming is now widely recognized in the scientific community. These changes are mainly caused by the increase of greenhouse gases, among which the carbon dioxide (CO2) is considered as a major gas. Recent studies showed that abiotic changes will impact the entire ecosystem, and more particularly multitrophic interactions, which are strongly dependent on their environment. In this study, we hypothezise that an increase of atmospheric CO2 concentration and mean temperature will impact the interactions between a plant, a pest aphid, the mutualistic ant of this aphid and its natural enemy, the hoverfly. Since organic volatile compounds are involved in these interactions, we first studied the impact of the two abiotic factors on their emission by two plants, Vicia faba and Triticum aestivum and evaluated the capacity of the plant to attract their pests, respectively Aphis fabae and Sitobion avenae. An elevation of temperature, whether or not coupled with CO2 impacted the volatile profiles of these two plant species as well as the concentration of particular compounds of the terpene and alcohol family. These modifications did not impact the foraging behavior of aphids, which indiscriminately located and selected plants grown under ambient or elevated conditions. During infestation, these volatile profiles evolved in the same way under the different climatic conditions. Secondly, we evaluated the impact of temperature on the mutualistic interaction between the aphid A. fabae and the ant Lasius niger. The mean temperature of 23°C estimated for the end of the 21th century reinforces this interaction, by an increase of ants flows and their collection of honeydew. These positive effects are more attenuated, and the balance of this interaction seems to weakened when one considers one of the most pessimistic climatic models with a 6°C increase (26°C). Aphid honeydew has a preponderant role in multitrophic interactions. The combination of temperature and CO2 concentration increases the honeydew production as well as its concentration in sucrose and melezitose, which are attractive to ants. On another hand, a high concentration of CO2 had an impact on the volatile profile of the honeydew, but these changes did not affect the oviposition behavior of the hoverfly Episyrphus balteatus, known to use honeydew volatiles, as well as the aphid alarm pheromone, to locate the most suitable sites for oviposition. Taken together, these results demonstrated that the predicted increase of temperature and CO2 concentration will have a significant influence on multitrophic interactions, but its understanding remains complex and challenging. [less ▲]

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See detailGenetic engineering of Yarrowia lipolytica for the production of thiol compounds from organic by-products
Do Thi Hoang, Diem ULiege

Doctoral thesis (2020)

Tripeptide glutathione (GSH), the most abundant non-protein thiol compounds in cells, plays an important role in many cellular mechanisms. GSH is also a biotechnology-oriented molecule with applications ... [more ▼]

Tripeptide glutathione (GSH), the most abundant non-protein thiol compounds in cells, plays an important role in many cellular mechanisms. GSH is also a biotechnology-oriented molecule with applications in medicine, food, and cosmetics. The GSH precursor, namely gamma-glutamylcysteine (γ-GC), has also shown its therapeutic potential. Y. lipolytica is a non-conventional yeast and is of interest as a cell factory for pharmaceuticals, food- and feed-related applications. In this thesis, we firstly improve the glutathione production in Y. lipolytica by overexpression of the endogenous biosynthetic genes GSH1 and GSH2, encoding γ-glutamylcysteine ligase (GCL) and glutathione synthetase (GS) enzymes, respectively. The strain was further engineered for the ability to metabolize carbon sources from organic wastes including glycerol, lactose, starch, and inulin. The glutathione overproducing strain with inulin-adapted metabolism showed the highest GSH productivity. During bioreactor culture, maximal productivity and yield from inulin were 510 μmol/gDCW and 626 mg/L, respectively. One of the main bottlenecks in glutathione overproduction is the feedback inhibition of the GCL enzyme by glutathione. Unfortunately, multicopy integration of the GSH1 gene did not overcome this bottleneck. As a second strategy to increase thiol accumulation, we focused on glutathione precursor γ-GC, a dipeptide that can substitute for GSH in some cell mechanisms. We firstly disrupted the GSH2 gene before overexpressing GSH1 in multicopy. The constructed strains showed an increase in intracellular thiol production as demonstrated by means of NMR and LC-QTOF/MS as well as thiol measurement in the cell extract. [less ▲]

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See detailUpset democracy: the paradoxes of developing worker participation in challenging environments
Soetens, Aurélie ULiege

Doctoral thesis (2020)

In this dissertation, my ambition is to offer a better understanding of the development of democratic enterprises. I focus on ways to develop and maintain worker participation in challenging environments ... [more ▼]

In this dissertation, my ambition is to offer a better understanding of the development of democratic enterprises. I focus on ways to develop and maintain worker participation in challenging environments. To do so, I investigate three democratic enterprises operating in different contexts: Venezuela, Belgium and Chile. First, I examine what are the structure and meaning of participation, and who are the individuals who give its form and content to participation (i.e., the ‘architects’ of participation). Second, I review the strategies that these ‘architects’ deploy to develop and sustain participation, in relation to their perceptions of the organisation’s environment. Third, I discuss the unintended consequences and contradictions resulting from their attempts to create an alternative reality within the organisation’s boundaries. Among others, the findings help advance an understanding of participation not only as a specific management and governance practice, but also as a cognitive, relational, perceptual, and political phenomenon. Analysing the development of democratic enterprises in terms of paradoxes helps grasping their inherently complex, contingent, and imperfect nature. The case studies show that, as the ‘architects’ of participation will try to advance their own agenda within an organisation that brings together individuals with different perceptions, and in order to ensure the perpetuation of their democratic project, they may develop practices of coercion, authority, and exclusion, despite initial ambitions to achieve democracy, equality, and freedom. This study, therefore, reveals how politics and power relations, but also the values, emotions, and perceptions of the workforce, shape interactions between individuals, organisations, and their environments. Finally, it depicts prefiguration as a struggle and a process, wherein a balance should constantly be found between utopian ideals and social reality. [less ▲]

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See detailCaractérisation de la diversité des stratégies conçues par les producteurs laitiers wallons : déterminants socio-économiques et dynamique d’adaptations face aux enjeux passés, présents et futurs
Dalcq, Anne-Catherine ULiege

Doctoral thesis (2020)

Agricultural producers are necessary for reasons of food security but they are subject to great economic, social and environmental issues, jeopardizing their continuity. More particularly, the European ... [more ▼]

Agricultural producers are necessary for reasons of food security but they are subject to great economic, social and environmental issues, jeopardizing their continuity. More particularly, the European dairy producers have recently experienced a big change of their economic and political context following the end of the dairy quota system. For the sustainability of the sector and what this implies for our society and our environment, it is interesting to know the development paths implemented, planned and considered by the producers facing these changes. This thesis studied these development paths from the point of view of the producers, who are the first to be impacted by these changes of context and the first actors of solutions needed to adapt and maintain a profitable activity. The actions and the opinions of the Walloon producers were studied using the technicoeconomic database of Elevéo as well as surveys conducted in 2014-2015 and 2020. The objectives of the thesis were (1) to study the strategies of the producers and the evolution of these strategies in a recent past, their planning from 2020 onwards and their consideration for an ideal future, (2) to study the link between these strategies and other information, reflecting the causes of these choices, the environmental considerations, the wishes for training and the quality of life of the producers, providing an insight of the determining factors and the sustainability of these strategies, (3) to study the relevance to adapt the management depending on the adopted strategy(ies). First, the level of intensification was measured in this thesis thanks to an index created on the basis of several variables related to feeding, coming from the technicoeconomic database. This index aims to provide a more complete and exact measure tool of intensification. Its evolution between 2007 and 2017 was measured per individual to highlight the evolution patterns. We observed that 27% of producers were having a constant evolution, 8% a linear positive tendency, 24% a quadratic evolution with a maximum in 2012, which was a year of dairy crisis. Secondly, just before the end of the dairy quota system (2014-2015), 3 strategies of production in the short term in post quota era were studied and concerned: the increase of the milk quantity produced, the alternative valorization of milk production and the diversification of the activities. We found out that, according to the survey, more than half of the producers (55%) have chosen the status quo in quantity of milk produced, nearly 40% the increase of the production, 10% the alternative valorization and 10% the diversification of the activities. This shows that alternative activities were seldom considered by the producers on the eve of an important change of the production framework, in contrast to the increase of the dairy production activity. Thirdly, the characteristics of the ideal farm of the future were studied throughout 7 strategies : intensive vs. extensive, specialized vs. diversified, weakly vs. strongly based on new technologies, management by an independent producer vs. by an association of producers, familial vs. salarial workforce, production of milk with a standard vs. differentiated quality, for the global vs. local market. From the multivariate analysis of the answers of the producers collected in the 2014-2015 survey, clusters between some characteristics were observed, leading to highlight two models of ideal future farm : the “Local-based extensive”(LBE) model and the “Global-based intensive” (GBI) model supported, respectively, by 26% and 46% of producers respondents. The producers were positioning themselves more or less strongly regarding these two extremes. Hence, a gradient of ideal future farm (IFF) between the model LBE and GBI was defined to express the tendency of a producer to consider a model or the other as ideal. Significant relationships were then observed between the IFF gradient and the variables related to the reasons of the choice of this model, the environmental considerations and the training. Thus, the producers tending to GBI or LBE model do not have the same environmental considerations and represent two different guests in terms of training paths and areas. Fourth, the producers with different production systems were selected to answer a survey concerning their quality of life. No significant relationship was observed between the variables linked to quality of life and their production profile, except for the mixed producers (i.e., having several activities on the farm, i.e., 3rd group that standed out of the variability of the surveyed producers) who showed some lower quality of life results and for the extensive producers who were better supporting the society perception of the agriculture. Thus, the farm model does not seem to impact the quality of life of the producers, except if they have several activities. Fifth, we studied the relevance to vary a management parameter in particular, the calving interval (CI), as a function of the feeding systems. Significantly different gross margins per cow were observed between the herds having different percentages of cows with short or long CI, inside the different feeding systems. This chapter allowed to understand the effects of feeding on the herd and the importance to take them into account to define the herd management that maximizes the economic results. Finally, all these results allowed to establish a temporal evolution of the strategies of dairy producers, to provide an overview of the sustainability of the two models of farm supported for the future and to draw a scenario of the causes leading to this choice. The survey of 2020, conducted in Wallonia, allowed to bring additional information regarding the points raised in this thesis, 5 years after the end of the dairy quota system. The results of this survey validate or record the evolution of the tendencies observed previously and show a change of strategy concerning the ideal future farm. Indeed, the current occurrence is that 49% of the producers are in favour of LBE model vs. 33% of GBI model. In conclusion, the strategies of dairy producers are multiple and have evolved these last years, in relation to the available resources, the mentality of the producers and the changing framework, whose major event was the end of the dairy quota system. The occurrence of the producers between LBE and GBI is important to know given their economic, social and environmental sustainability. Thus, in order to build a suitable framework for the dairy activity for the next years and generations, this information must be taken into account by all the actors on the ground. [less ▲]

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See detailModel of motivation in schizophrenia: Development and validation of a multifactorial intervention aiming to enhance daily functioning and quality of life
Thonon, Bénédicte ULiege

Doctoral thesis (2020)

People diagnosed with schizophrenia experience a number of difficulties in their daily life. An important barrier to daily functioning and quality of life is negative symptoms, motivational deficits in ... [more ▼]

People diagnosed with schizophrenia experience a number of difficulties in their daily life. An important barrier to daily functioning and quality of life is negative symptoms, motivational deficits in particular. Negative symptoms are, however, resistant to pharmaceutical treatment. Yet, very few interventions that target negative symptoms are available and those studies that have included such interventions suffer from a number of limitations. The goal of this research project was to develop a multifactorial intervention, “Switch”, based on a solid model of motivation in schizophrenia which identifies the various affective, cognitive and behavioural processes that underpin motivation and goal-directed behaviours. Switch targets the specific dysfunctions that appear in the processes identified in this model and uses a variety of therapeutic tools. The efficacy and effectiveness of the Switch intervention is evaluated through three studies. The first pilot study evaluates the efficacy of Switch delivered in individual sessions for around one year. The second study assesses the effectiveness of Switch in a naturalistic setting, through three case-studies. The third study evaluates the preliminary efficacy of the group version of Switch. The second and third studies include daily-life assessments which allow to generate hypotheses on how motivation and related processes evolve during the course of the intervention. Finally, a fourth study evaluates the dynamics between the processes related to motivation and goal-directed behaviours through network analyses. Together these four studies provide preliminary evidence that Switch is a promising psychotherapeutic intervention that may increase motivation and guide individuals with schizophrenia on a more enjoyable and meaningful path, and emphasize the benefits of integrating various processes, with a particular focus on hedonic capacities. [less ▲]

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See detailStudy of the pathogenesis of Usutu virus infection in ovo and in vivo
Benzarti, Emna ULiege

Doctoral thesis (2020)

Usutu virus (USUV) is a mosquito-borne flavivirus, closely related to the West Nile virus (WNV). Similar to WNV, USUV may cause infections in humans, with occasional, but sometimes severe, neurological ... [more ▼]

Usutu virus (USUV) is a mosquito-borne flavivirus, closely related to the West Nile virus (WNV). Similar to WNV, USUV may cause infections in humans, with occasional, but sometimes severe, neurological complications. Further, USUV can be highly pathogenic in wild and captive birds and its circulation in Europe has given rise to substantial avian death. Adequate study models of this virus are still lacking but are critically needed to understand its pathogenesis and virulence spectrum. In this thesis, we used natural infection cases and experimentally infected animals (chicken embryos, canaries and immunocompetent mice) to fill some gaps in our knowledge regarding the pathogenesis and epidemiology of USUV in Belgium. [less ▲]

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See detailHow to finance agricultural activities in mountainous areas of Viet Nam? A case study in Lao Cai province
Bui Thi Lam, ULiege

Doctoral thesis (2020)

In the Northern Midlands and Mountains (NMM) region, the agricultural sector plays an essential role in the local economy because it is the main livelihood of the majority of the rural population. Among ... [more ▼]

In the Northern Midlands and Mountains (NMM) region, the agricultural sector plays an essential role in the local economy because it is the main livelihood of the majority of the rural population. Among the factors influencing agricultural development, capital/financing has been becoming increasingly important because it affects the inputs used, investment in fixed assets, and the application of advanced technology. Unfortunately, the NMM region is the poorest area of the country, therefore, almost farmers here lack of capital to finance their agricultural production. This explains the reason why they still remain to be stuck in the cycle of chronic poverty: low investment, low productivity, low income. Moreover, several recent empirical studies reveal that agribusiness and other agriculture-based actors in Viet Nam also face with financial shortages. This study, therefore, examines financial demands of farmers and other farming actors in Lao Cai province as well as their constraints to access affordable credit to finance agricultural activities, and then, suggests feasible recommendations to increase funds to agriculture in the research site. In this study, we approach the agricultural financial markets in Lao Cai province based on financial supply-side and demand-side analysis. On the supply side, 24 in-depth interviews with financial providers about their agricultural credit provision were conducted. On the agricultural finance demand side, we study two subclasses: (i) agricultural production by local farmers and (ii) the Seng Cu (SC) rice value chain, including production, processing, and consumption activities. At the general level, agricultural production, the study surveyed 193 farm households to determine their financial needs and their actual access to credit for agricultural investments. At the agricultural value chain financing analysis, we conducted 160 SC rice producers and 31 chain actors (small collectors, large collectors, and retailers). In addition, two econometric models are applied to determine the factors affecting the results of banking credit application of households; and, the influence of internal and external financing on SC rice production. Our findings show that the financial sources for agricultural activities are diverse: formal sector (two state-owned banks: VBARD and VBSP); semi-formal sources (Farmers’ Union, Women's Union); informal actors (moneylenders, friends, relatives), and direct Government’s subsidies (Program 135, 30A and World Bank’s Project). Compared to other financial providers, VBARD and VBSP have many advantages related to loanable funds, transaction points, and low-interest credit. However, credit provision of banks likely creates credit constraints to local farmers. Specifically, VBARD just devoted a small proportion (18.3%) of credit volume to farmers. In addition, VBARD’s and VBSP’s decision-making on disbursement strongly depends on assessments of local authorities, it is sometimes distorted by nepotism. In addition, credit services in terms of duration and repayment methods are not much improper, compared to clients’ demands. The survey of 193 farm households shows that a large proportion (84%) of the households have high credit demand because their own capital is not enough to finance their agricultural activities. Among farmers applied a loan at banks, 48% of them received nothing or smaller loans than their desires. They are mainly small and medium farmer households. Using the Multinomial Logistic Model (MLM), the study points out determinants of credit access of households: (i) lack of collateral; (ii) lack of good relationships with local authorities involved in application screening, (iii) low human capital (education/ethnicity). Difficulties in formal credit access, these farmers often fall into the following three actions: 1) reduce investment in agriculture; 2) using a large proportion of self-produced and low-quality inputs; and/or, 3) borrow money from informal lenders at very high interest rates. All these actions make agricultural production inefficient and undermine farmers’ income. Arguably, although they are the beneficiaries of the preferential credit policy, they are often excluded from the formal credit market, which leads them still to be stuck in a vicious cycle of chronic poverty. Likewise, the majority of actors participating in the SC rice value chain had high specific financial needs. SC rice growers received high-quality inputs and technical assistance from the input supplier (JVC) and the purchasing enterprise (TPC), which help them to reduce diseases, price, and market risks. Besides the advantage of SC rice's selling retail price, the linkages between chain actors contributed to the great potential of this value chain. However, banks still maintained the strict risk-avoidance strategy, which strongly depends on collateral of individual chain actors, not the entire chain. As a result, almost chain actors received lower-than-expected loans from banks, especially SC rice growers in uplands and TPC. From the above research results, we can conclude that improving banks’ efficiency in credit provision and banks’ participation in the chain are the first steps to improving the agricultural finance system in the research site. In addition, farmers and other chain members need to improve their production capacity and financial management in order to be assessed creditworthy by the bank. In addition, it is necessary to enact new legal regulations from the Government to encourage value chain financing models nationwide and to support the infrastructure system in mountainous areas. The coordination among four key players: producers, businesses, banks, and the public sector is a comprehensive solution for agricultural finance in the research site. [less ▲]

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See detailConception et modélisation des réseaux de diffraction pour imageur hyperspectral miniature dans le domaine du visible à l'infrarouge moyen
Sabushimike, Bernard ULiege

Doctoral thesis (2020)

Les applications de l'imagerie hyperspectrale toujours croissantes exigent une résolution spectrale et spatiale de très bonne qualité. Les spectro-imageurs à réseau de diffraction sont donc privilégiés ... [more ▼]

Les applications de l'imagerie hyperspectrale toujours croissantes exigent une résolution spectrale et spatiale de très bonne qualité. Les spectro-imageurs à réseau de diffraction sont donc privilégiés car ils offrent une résolution spectrale élevée pour une bande spectrale large par rapport aux autres types comme ceux à prisme ou à transformée de Fourier. De plus, la miniaturisation des instruments hyperspectraux tendant à se généraliser, il faut un type de réseaux qui répond à cette exigence. Les réseaux convexes sont exploités à cette fin surtout qu'actuellement, il existe des méthodes de leur fabrication. Ce type de réseau dans une configuration de type Offner offre beaucoup d'avantages : cette configuration offre un champ de vision plus large et des aberrations plus faibles. Ces spectromètres ont une structure concentrique et donc une conception compacte. Ils fonctionnent avec un F number relativement faible ($\leq f / 2$), acceptent une longue fente tout en conservant une taille compacte et n'ont besoin que de trois surfaces optiques. L'utilisation de cette conception a abouti à des spectromètres d'imagerie avec des valeurs extrêmement faibles de distorsion spatio-spectrale. Le premier objectif de la thèse est de faire une conception et modélisation des réseaux de diffraction pour imageur hyperpectral. Le deuxième objectif de la thèse est d'étudier l'impact des profils réalistes sur l'efficacité de diffraction et la sensibilité à la polarisation. La plupart des fois, les utilisateurs finaux des imageurs hyperspectraux donnent la courbe d'efficacité de diffraction qu'ils veulent en fonction de leurs applications. Il appartient aux concepteurs /fabricants de trouver une géométrie du réseau qui doit répondre aux exigences en termes d'efficacité de diffraction. Il existe deux types de réseau : un réseau mono-blaze et un réseau multi-blaze. Le réseau mono-blaze est un réseau optimisé à une seule longueur d'onde de blaze c'est-à-dire un réseau à profil uniforme. Le réseau multi-blaze est un réseau optimisé à plusieurs longueurs d'onde, c'est-à-dire un réseau à plusieurs profils ou un ensemble de sous réseaux chacun avec son propre poids c'est-à-dire sa contribution sur la surface du réseau. Dans cette thèse, nous avons d'abord travaillé sur l'optimisation du réseau de l'instrument hyperspectral Chandrayaan 2 (projet exécuté par AMOS pour le compte de l'organisation de recherche spatiale indienne) pour l'observation de la lune dans l'infrarouge. Nous avons proposé une méthode d'optimisation basée sur une approche intuitive d'approximation qui nous a permis d'arriver à une courbe d'efficacité de diffraction dans la fourchette exigée. L'instrument est actuellement sur orbite et fournit de très belles images. Nous avons continué à travailler sur le processus d'optimisation et avons proposé une méthode basée sur la théorie scalaire diffractive et la fonction Matlab \textit{fsolve}. La méthode permet, à partir de la courbe d'efficacité et des valeurs sélectionnées sur cette dernière, de trouver la longueur d'onde ou les longueurs d'onde de blaze et leurs poids ainsi que la marge qui est une valeur d'efficacité de diffraction qu'on ajoute à celle exigée pour déterminer ces paramètres du réseau afin de prévoir les dégradations du réseau après fabrication. C'est une méthode de résolution d'un système d'équations non linéaires en utilisant la méthode de Levenberg-Marquardt. Il faut donc construire un système d'équations à n variables, n variant de n=2 (réseau mono-blaze) à N (nombre de longueurs d'onde de blaze, de leurs poids et la marge qui résulteront du processus d'optimisation). Le nombre d'équations reste inchangé et égal au nombre de valeurs sélectionnées sur la courbe d'efficacité de diffraction de référence pour chaque système. Cette méthode a été appliquée en premier sur le réseau de l'instrument hyperspectral THEO (Technologies for Hyperspectral Earth Observation) développé aussi par AMOS pour le compte de l'ESA. Le processus d'optimisation a abouti à une conception réseau de 3 longueurs d'onde de blaze. Après, il fallait revenir sur le réseau de l'instrument Chandrayaan 2 pour appliquer cette méthode d'optimisation et on est passé d'une configuration de 9 longueurs d'onde de blaze à une configuration de 3 longueurs d'onde de blaze avec pratiquement les mêmes résultats. C'est dans les deux versions de conception du réseau de Chandrayaan 2 que l'étude de l'impact des profils réalistes sur l'efficacité de diffraction et la sensibilité à la polarisation a été effectuée. Nous avons appliqué la méthode pour la conception du réseau de la mission CHIME (The Copernicus Hyperspectral Imaging Mission) pour soutenir en particulier des services nouveaux et améliorés pour la sécurité alimentaire, l'agriculture durable et les matières premières. Cela comprend la gestion de la biodiversité, la caractérisation des propriétés des sols, les pratiques minières durables et la préservation de l'environnement en Europe. Enfin, dans la thèse on montre qu'on peut utiliser la méthode pour l'optimisation du réseau dans deux ordres de diffraction de façon simultanée (l'ordre 2 du visible au proche infrarouge et l'ordre 1 dans l'infrarouge onde courte par exemple). L'application est faite sur la conception d'un réseau de l'instrument hyperspectral THEO (Technologies for Hyperspectral Earth Observation), deuxième variante du réseau du même instrument déjà évoqué. Tous ces projets ont été exécutés par AMOS, notre partenaire dans la thèse [less ▲]

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See detailPersonal dosimetry of workers without a physical dosemeter using computational methods
Abdelrahman, Mahmoud Eid Mahmoud ULiege

Doctoral thesis (2020)

Monitoring the individual exposure of workers constitutes an integral part of any radiation protection program. Individual monitoring of exposed workers to external ionizing radiation is essential in ... [more ▼]

Monitoring the individual exposure of workers constitutes an integral part of any radiation protection program. Individual monitoring of exposed workers to external ionizing radiation is essential in order to ensure safe and satisfactory working conditions; demonstrate compliance with dose limits and the application of the ALARA principle. At present, personal dosimetry is typically performed by issuing staff with physical dosimeters. These physical measurement devices are part of routine practice, but still have many limitations, both from a practical and from a metrological point of view. The results are usually known only after some delay (30-60 days) with passive dosimeters. In addition, performing precise and reliable personal dose measurements in all types of workplaces is quite difficult. There are issues with compliance and multiple dosimeters can be mixed up or worn incorrectly. The number and positioning of individual dosimeters is becoming more complex with the new focus on eye lens dosimetry. Also, the uncertainties with the present dosimeters are not negligible. An uncertainty factor of 2 is accepted as good practice for low doses and for neutron fields in particular the uncertainties are even higher. On the other hand, computational techniques are evolving rapidly. In the past, simplified mathematical phantoms were used, while now very detailed voxel and mesh phantoms are available. In addition, with increasing computational power, such calculations can be performed faster and faster. The objective of this thesis work is to improve occupational dosimetry by an innovative approach: the development of a computational dosimetry application based on Monte-Carlo (MC) simulations without the use of physical dosimeters. This is done using a combination of (i) monitoring of the position of workers in real time and (ii) the spatial radiation field, including its energy and angular distribution. With this input, the doses of the workers can be simulated or calculated. The methodology was applied and validated for two situations where improvements in dosimetry are urgently needed: neutron and interventional radiology workplaces. Human motion tracking system was developed to monitor worker’s movements. The movement of the worker is then used to animate an anthropomorphic flexible computational phantom. As regards interventional radiology workplaces, the required information and data sources have been identified. In particular, for the calculations the most reliable way to gather the required information is from the Radiation Dose Structured Report (RDSR). For neutron fields, the radiation field map of the workplace can be based on analytical calculations or more advanced MC calculations. This proposed methodology for personal dosimetry for workers is very innovative and challenging. It explores a new direction in personal dosimetry and, as such, adds value to the radiation protection community and regulatory system. In addition, the proposed approach can be used for ALARA optimization, as well as for education and training activities. [less ▲]

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See detailContinuous flow strategies for the upgrading of bio-based molecules
Gerardy, Romaric ULiege

Doctoral thesis (2020)

In the current context of fossil resources depletion and global warming, the upgrading of biomass-derived molecules for the manufacture of fuels and chemicals sustains major research interests. Continuous ... [more ▼]

In the current context of fossil resources depletion and global warming, the upgrading of biomass-derived molecules for the manufacture of fuels and chemicals sustains major research interests. Continuous flow technology holds great potential for the development of chemical facilities with low footprint, improved performance and reduced hazards. This PhD dissertation gathers our results for the upgrading of a selection of low molecular weight bio-based molecules into higher value-added chemicals. Continuous flow procedures were developed to provide robust, versatile, sustainable and scalable technologies for the preparation of chemicals of high industrial relevance. [less ▲]

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See detailLes dystonies focales de l'enfant
DEPIERREUX, Frédérique ULiege

Master of advanced studies dissertation (2020)

Children focal dystonias: their etiologies, differential diagnosis, investigations and treatment. Case report serie (DYT1, DYT28, DYT11, etc.).

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See detailLeaving Europe: Emigration, aspirations and pathways of incorporation of Maghrebi French and Belgians in Montréal
Mandin, Jérémy ULiege

Doctoral thesis (2020)

When it comes to migration, Western European countries such as Belgium and France are typically described as destination countries. Yet, emigration remains an important phenomena in most of European ... [more ▼]

When it comes to migration, Western European countries such as Belgium and France are typically described as destination countries. Yet, emigration remains an important phenomena in most of European societies. This emigration is often portrayed as somehow different from migrations ‘from the South.’ The western European migrant – sometimes referred to as ‘expat’ – is generally depicted as a dynamic individual characterized by an entrepreneurial spirit and a taste for adventure. At a time where many European societies experience both the consequences of financial and economic crisis and growing tensions about cultural and religious diversity, very few attention has been given to the relation between such structural dynamics and the emergence of emigration practices among young Europeans. This research is an attempt to explore such a relation by focusing on the migration practices of Belgians and French youngsters of Maghrebi origins leaving Europe for the Canadian city of Montréal. More precisely, the research focuses on the aspirations - defined as socially situated representations of the future – that inform the emigration practices of Maghrebi Europeans. Building on an ethnographic field research conducted in France, Belgium and in the city of Montréal, the thesis is an exploration of migration related aspirations and their evolution at three stages of the migration process: before departure, during migration and once arrived at destination. The goal of the research is to understand the factors that inform the development of emigration aspirations among Maghrebi European people, how these aspirations are channeled during migration and how they evolve after migration. Through the focus on migrants’ aspirations, the research questions how perspectives for a desirable future are distributed both in Europe and in Montréal and how this distribution is highly dependent of one social position. The collection of biographic interviews with Maghrebi European migrants allows to understand the various representations of the future that inform the emergence of migration desires. This highlights a set of various experiences – experiences of ‘existential stuckedness’ or of ‘existential mobility’ – that evolve during the migration process. The ethnographic data also allows to explore the various pathways of incorporation that are carved out by Maghrebi Europeans in Montreal in order to sustain possibilities for a desirable future. These pathways, sometimes constitutes alternatives to the types of incorporation promoted by the Canadian and Québec authorities. In this sense, looking at how migrants think about their future and how they try to organize it also highlights forms of agency that exceed societal expectations. [less ▲]

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See detailInsight into the role of Dual Specificity Phosphatase 3 in non-alcoholic fatty liver disease and insulin resistance
Jacques, Sophie ULiege

Doctoral thesis (2020)

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western countries. It encompasses a broad spectrum of liver conditions ranging from simple steatosis to the more ... [more ▼]

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western countries. It encompasses a broad spectrum of liver conditions ranging from simple steatosis to the more severe and progressive disease, non-alcoholic steatohepatitis (NASH) that can lead to hepatocellular carcinoma (HCC). Obesity and related metabolic syndrome and insulin resistance are important risk factors for the development of NAFLD, NASH and HCC. We investigated the impact of DUSP3 deficiency in metabolic syndrome manifestations and in HCC using a knockout (KO) mouse model. While aging, DUSP3-KO mice became obese and exhibited insulin resistance. These phenotypes were exacerbated under HFD and were accompanied by NAFLD and associated liver damages. In addition, DEN administration combined to HFD led to a rapid HCC development compared to WT mice. DUSP3-KO mice had more serum triglycerides, cholesterol, AST and ALT than control WT mice under both regular chow diet (CD) and HFD. The level of fasting insulin was higher compared to WT mice, though, fasting glucose as well as glucose tolerance were similar to those of control mice. At the molecular levels, HFD led to a decrease of DUSP3 expression at both protein and RNA levels. Under CD, DUSP3 deletion was associated with increased phosphorylation of the insulin receptor (IR) and subsequently, with higher activation of the downstream signaling pathway. The difference of IR phosphorylation was maintained between mutant and WT mice under HFD. However, IR downstream signaling pathway was equally activated in both groups of mice. Liver RNA sequencing and differential expression genes analysis demonstrated the effect of the diet on the expression of several genes, including genes from lipid metabolism. Gene set enrichment analysis highlighted pathways specifically regulated in DUSP3-KO mice, such as fatty acid metabolism and DNA repair pathways. Collectively, our results support a new role for DUSP3 in obesity, insulin resistance, NAFLD and liver damage. [less ▲]

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See detailCrystal Chemistry and Magnetism in the Polymorphs of Iron(III) Tungsten Oxide Fe2WO6
Caubergh, Stéphane ULiege

Doctoral thesis (2020)

Compounds with the general formula A2BO6, where A is a transition metal cation and B is a cation with a high nominal charge, have attracted interest due to the variety of their structures and the ... [more ▼]

Compounds with the general formula A2BO6, where A is a transition metal cation and B is a cation with a high nominal charge, have attracted interest due to the variety of their structures and the complexity of their physical properties. Within this family, Fe2WO6 is an interesting compound because of its three polymorphic structures (α, γ, and more recently β) and its magnetic and photoelectrochemical properties. However, the studies reported so far presented only a partial view of Fe2WO6, since they mostly focused on one polymorph (γ) and did not investigate the influence of the structures on the functional properties. In this manuscript, we present the study of the crystal chemistry of the three polymorphs of Fe2WO6 and report about their optical and magnetic properties. The developments of repeatable spray-drying synthesis procedures from aqueous Fe/W solutions and quantification by ICP-OES allowed us to prepare homogeneous powders with well-controlled Fe/W ratios. A solid solution domain was identified for Fe/W ratios in the [1.91-2.00] range and the general formula Fe2-2xW1+xO6 was proposed to describe the off-stoichiometry. The unknown nuclear and magnetic structures of polymorph β were solved by combining synchrotron X–ray diffraction, neutron diffraction and physical properties measurements. The structure of polymorph α was revised and the impact of the synthesis-dependent cationic ordering in polymorph γ is discussed. The polymorphic transitions and the structural and magnetic relationships with other related compounds (FeWO4 and Fe2TeO6) are also presented. [less ▲]

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See detailFirst- and Second-Principles Studies of Perovskites
Schmitt, Michaël ULiege

Doctoral thesis (2020)

The Metal-Insulator transition (MIT) upon cooling at elevated temperatures is a fascinating effect that is observed in some ABX 3 perovskite compounds with specific electronic configurations on the ... [more ▼]

The Metal-Insulator transition (MIT) upon cooling at elevated temperatures is a fascinating effect that is observed in some ABX 3 perovskite compounds with specific electronic configurations on the transition metal B cation d states. These compounds behave completely oppositional to ordinary metals who become better conductors upon cooling. At the MIT temperature these specific perovskite compounds show electron localization accompanied by cooperative lattice distortions that deform the BX 6 corner shared octahedral network. Since the discovery of these MITs, theoretical concepts about its origin have been proposed and debated. In this work we study from ab initio density functional theory (DFT) calculations LaMnO 3 and the alkaline earth ferrite series AFeO 3 who all have a formal d 4 occupation. As a basis to our discussion we introduce canonical notations, that were missing until now, for lattice distortions in perovskites that distort the X anion octahedra and are connected to MITs. While LaMnO 3 shows electron localization through orbital ordering - the appearance of a static order of Mn d orbital occupations-, CaFeO 3 shows electron localization through charge ordering - the appearance of a static order of formal Fe charges-. From DFT calculations we can show that both mechanisms are compatible with the concept of a Peierls transition and are enabled by octahedral rotations. From Monte-Carlo simulations we show furthermore that spin disorder in the paramagnetic phase is a key ingredient to explain the high MIT temperatures. Last we study the influence of external epitaxial strain on these compounds. Here, our canonical notations help to discriminate internal relaxations and external constraints. Our calculations show that in LaMnO 3 epitaxial strain alone can provoke a change from an antiferromagnetic to an ferromagnetic order without the necessity of Oxygen vacancies as has been often speculated. In CaFeO 3 epitaxial strain can provoke a change from the bulk charge ordering MIT to an orbital ordering MIT, which explains the experimental finding of a strongly elevated MIT in CaFeO 3 thin films. In the second part of this work, we present methodological developments for generating effective lattice potentials by a polynomial expansion that describe electronic potential energy surfaces in which atomic nuclei move. This is the so-called second-principles approach. The aim thereby is to replace the computational intensive self consistent DFT procedure by an lightweight evaluation of a polynomial depending on nuclear positions. If successful, this approach provides a mean to achieve a scale-transfer retaining the accuracy of ab initio calculations applicable to large scale systems with many thousand atoms and statistical simulations. In a proof of concept study we apply this approach to the perovskite CaTiO 3 . The retained effective potential reproduces with good accuracy a number of ab initio quantities. Moreover, in the low to average temperature range (T<=1000K) the lattice dilatation of CaTiO 3 is well described. In the highest temperature range the effective potential deviates from the experimentally measured lattice dilatation and proposed phase transition sequence that is itself, however, debated. We conclude that the lattice dilatation properties can be refined by extending the lattice expansion and that a reexamination of the high temperature phase sequence of CaTiO 3 due the the information of our effective potential might be meaningful. Finally, we also highlight that there exists a strongly ferroelectric low energetic phase of CaTiO 3 whose stabilization through external constraints is part of ongoing research. [less ▲]

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See detailAllegorical Home, Trauma, and Abjection in Toni Morrison's Post- Nobel Fiction
Tine, François Dassise Kheyane ULiege

Doctoral thesis (2020)

This dissertation analyzes Toni Morrison’s final five novels, namely Paradise, Love, A Mercy, Home and God Help the Child and seeks to explore the trope of home in every sense of the word—including the ... [more ▼]

This dissertation analyzes Toni Morrison’s final five novels, namely Paradise, Love, A Mercy, Home and God Help the Child and seeks to explore the trope of home in every sense of the word—including the allegorical representation of the United States in the black American experience—as a house haunted by both racialized and sexualized violence to probe the legacies of masculine and political violence as well as the trauma of dispossession that haunts African Americans. Home has been considered as the symbol of psychic imagination and at the core of under scrutiny lies its power to generate healing: transcending the wounds of the past, re-envisioning and transforming the home into self-nurturing and self-validating place rely on the characters’ awareness of their traumas and on their deepening sense of personal responsibility. In other words, the literary texts under study maintain that, despite the characters’ traumatic experiences which have disrupted their notions of home and belonging, it is the characters’ endeavor and personal duty to reconstruct a real sense of home by working through their traumas. At the intersection of literary studies, cultural studies, and trauma studies, each part of the dissertation is devoted to the study of a novel and focuses on the writing of Otherness and the process of Othering as means by which Morrison explores the nightmarish yet complex relationship African Americans have experienced when it comes to home and belonging and how they endeavor to reconstruct a sense of home in a land of deep racial animus. Through the prism of postcolonial theories, black feminist thought, the theory of abjection, gender studies and gothic theories of race, Morrison’s later novels portray issues of broken families, ruptured communities, and socio-economic marginalization and force the reader to reconsider the different forms of exclusion and gendered violence African Americans continue to endure in the U.S. Because of traumatic displacements, the pervasiveness of intraracial violence and the traumas ensuing from any kind of domination, the texts under scrutiny contend that home is only a vague promise for many black Americans. I shall maintain that rather than a specific geographical or physical location, home must be regarded as an imagined ideal that enables healing and self-validation. Central to Morrison’s literary project is the deconstruction of idealized notions of manhood and race that impede self-awareness and true spiritual growth. Key Words: Toni Morrison, trauma, home, belonging, race, abjection, heteronormativity and masculinity, Gothic theory, postcolonial theory. [less ▲]

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See detailCARACTÉRISATION DE L’OSTÉOINTÉGRATION D’UNE XÉNOGREFFE D’ORIGINE ANIMALE AU SEIN D’UN DÉFICIT ÉPIPHYSAIRE DE TYPE CAMÉRAL CHEZ LE LAPIN
Picavet, Pierre ULiege

Master of advanced studies dissertation (2020)

Disposer de matériaux de greffe afin de combler les déficits osseux d'origine traumatique ou néoplasique a toujours été une préoccupation dans le domaine de la chirurgie orthopédique vétérinaire et ... [more ▼]

Disposer de matériaux de greffe afin de combler les déficits osseux d'origine traumatique ou néoplasique a toujours été une préoccupation dans le domaine de la chirurgie orthopédique vétérinaire et humaine. Les xénogreffes sont couramment utilisées en raison de leur grande disponibilité, même si les greffes osseuses autologues sont toujours considérées comme la référence en pratique clinique malgré de nombreuses limitations. Des recherches approfondies sont actuellement en cours au sujet de matériaux synthétiques et biomatériaux dont les performances in vivo sont étudiées avec des modèles chez les animaux pour combler un déficit osseux de taille critique. Le bois de cerf est une structure osseuse primaire facile à collecter et qui pourrait servir de xénogreffe. Cette étude examine le comportement de cylindres d’os spongieux de bois de cerf élaphe comblant un déficit osseux spongieux de taille critique chez le lapin et évalue l’effet de protocoles de décellularisation. Onze lapins de Nouvelle-Zélande blancs en bonne santé âgés de 6 à 7 mois avec un poids moyen de 4,2 kg ont été utilisés. Des cylindres (10x4,8mm) en os spongieux en bois de cerf avec une porosité de 42,1% ± 0 ,9 ont été implantés dans des conditions aseptiques dans l'épiphyse fémorale distale bilatéralement. Pour évaluer le rôle des protéines et des lipides, deux régimes de préparation (A et B) de la xénogreffe ont été utilisés. Les radiographies ont été prises immédiatement après la chirurgie et juste après l'euthanasie 12 semaines après l'implantation. L'évaluation histologique a été réalisée sur des coupes non décalcifiées de 10 microns avec un protocole de coloration picro-fuchsine van Gieson. Une région d'intérêt a été définie pour chaque coupe histologique, évaluant la réaction inflammatoire, le processus de fibrose et l’ostéogenèse. Chaque section histologique a finalement été microradiographiée pour évaluer le contact osseux, la présence de synostose, les processus de remodelage et d'ossification. Tous les cylindres de bois ont été implantés avec succès et tous les lapins se sont bien remis de la chirurgie sans signes d’ostéomyélite. L'analyse radiographique finale a démontré l'ostéointégration de la plupart des implants à différents stades. Une réaction inflammatoire légère à modérée autour des greffons fut notée à l’histologie, avec un seul cas montrant une encapsulation complète. Un degré d'intimité variable entre l'implant et l'os hôte a été mis en évidence à la microradiographie, avec un remodelage osseux et une nouvelle ostéogenèse d'intensité variée présents dans tous les sites implantés. De façon surprenante, la présence ou l'absence de lipides et de protéines dans les greffons ne semble pas avoir d'importance. Les protocoles de décellularisation et de stérilisation pourraient être incriminés. Bien que présentant plusieurs limites, cette étude montre des résultats prometteurs justifiant des investigations supplémentaires. [less ▲]

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See detailInterplay between lattice, strain, spin and electronic degrees of freedom in eg1 perovskites
Zhang, Yajun ULiege

Doctoral thesis (2020)

ABO3 perovskites, with a B cation in a eg1 electronic configuration, have long been the focus of extensive research due to their promising metal-insulator transition (MIT) and related technological ... [more ▼]

ABO3 perovskites, with a B cation in a eg1 electronic configuration, have long been the focus of extensive research due to their promising metal-insulator transition (MIT) and related technological applications. However, because of the complex interplay between charge, orbital, spin and lattice degrees of freedom, distinct families of compounds like RMnO3, RNiO3, and AFeO3 perovskites, with R = rare-earth and A = alkaline-earth element, can exhibit quite different behaviors showing either orbital ordering and Jahn-Teller distortions or charge ordering and breathing distortions. What makes eg1 perovskites even more interesting is that the MIT property is extremely sensitive to external stimuli (e.g., strain, pressure, dimensionality, and stoichiometry). This provides an ideal platform to purposely tune related properties for versatile applications and has recently fueled significant research interest. In particular, epitaxial thin films and superlattices are two effective and promising approaches to tune MIT temperature (TMI ) in device applications. The great and recent advances in the synthesis of high-quality epitaxial thin films and superlattices spark rapidly increasing interest in the control of TMI. However, despite the effectiveness of tailoring TMI, their actual influence is quite complex, and different studies may give inconsistent conclusions. Over the past years, continuous efforts have been devoted to understanding the microscopic mechanism behind the evolution of TMI in eg1 perovskites thin films and superlattices. Nevertheless, for the thin films, there is still a lack of a reliable and general explanation to simultaneously describe the evolution of TMI under different strain conditions. In terms of superlattices, the roles of interface effect including the structural and electronic coupling, dimensionality, and confinement effect remain to be understood. In this thesis, combining first-principles calculations and Landau theory analysis, we explore comprehensively the interplay between lattice, strain, spin, and charge degrees of freedom in eg1 perovskites thin films and superlattices. We firstly investigate the origin of breathing distortions and charge ordering induced MIT in CaFeO3 from lattice coupling and electron-phonon coupling. Another aim is to rationalize the origin of a huge increase of TMI recently observed in CaFeO3 thin film under large tensile strain. We reveal that the breathing distortions, which are the origin of MIT, are triggered by the mode coupling with oxygen octahedral rotations. We further highlight that epitaxial strain can tune the balance between charge ordering and orbital ordering phases. More especially, epitaxial tensile strain favors the Jahn-Teller distortions and drives the phase transition from charge ordering to orbital ordering. Since the orbital ordering system like LaMnO3 tends to have a high value of TMI, we infer that the new orbital ordering phase results in the unusual increase of TMI observed in thin film under tensile strain. Then, we revisit the fundamental role of strain and pressure in several charge ordering perovskites. We propose that the effect of strain and pressure can be unified by the activation or tuning of specific strain modes, which in turn affect material properties through the direct and indirect strain-phonon-phonon coupling. Taking widely investigated NdNiO3 thin film as an example, we develop a new perspective on the mechanical control of TMI and formulate a reliable and general theoretical guidance for the rational control of TMI in experiments. Finally, we explore the superlattices composed of eg1 perovskites. The first purpose is to induce MIT in metallic eg1 perovskites like SrFeO3 through the superlattices strategy. The roles of cation ordering induced confinement effect, lattice distortions and strain have been carefully investigated, allowing us to reveal that both charge ordering and orbital ordering phases are unstable and capable to induce MIT by collaborating with cation ordering. Furthermore, we point out that the stability of the orbital ordering phase with Jahn-Teller distortions is very sensitive to epitaxial strain, while the charge ordering phase is insensitive to strain. Basing on this knowledge, we highlight that strain engineering can be utilized to switch between orbital ordering and charge ordering phases. More interestingly, we can purposely design charge ordering and orbital ordering ferromagnetic and ferroelectric multiferroics by selecting specific superlattices and strain conditions. Another aim is to rationalize the experimental findings of a collaborated work on (NdNiO3)m/(SmNiO3)m superlattices, which show layer thickness dependent MIT behaviors. From the view of first-principles calculations, we firstly helped to rule out the structural coupling at the interface as the key factor that controls the TMI evolution in the superlattices. Then we helped to verify the phase boundary energy between metallic and insulating phases as the dominant factor affecting the TMI proposed by our collaborators. Combining first-principles calculations, Landau model, and the experimental results, we convincingly propose a new paradigm to tune the TMI through controlling the layer thickness in the superlattices. Our findings not only extend the knowledge of tuning MIT in eg1 perovskites but also are important for practical applications. [less ▲]

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See detailBioanalytical applications of surface-enhanced Raman scattering: The protein corona challenge
Dumont, Elodie ULiege

Doctoral thesis (2020)

Concurrently with the recent expansion and diversification of bioanalytical applications, a wealth of analytical tools has developed to meet the expectations of bioanalysis. Among these tools, surface ... [more ▼]

Concurrently with the recent expansion and diversification of bioanalytical applications, a wealth of analytical tools has developed to meet the expectations of bioanalysis. Among these tools, surface-enhanced Raman scattering (SERS) stands out as an attractive alternative to separative techniques. SERS is indeed non-destructive, fast and can be used for identification and quantification purposes. In addition, SERS benefits from an increased sensitivity compared to conventional Raman spectroscopy, making it more suited to the detection of low concentrations of analytes that are often encountered in bioanalysis. However, some roadblocks on the way towards the use of SERS in routine bioanalyses have been identified. Complex biological matrices often call for either sample preparation or smart SERS substrate surface functionalisation. The former denatures the sample and requires additional steps of sample handling with frequent use of organic solvents, which are harmful for the environment. The latter can be laborious to carry out, needs experienced staff and is limited to some specific analytes. Moreover, in view of routine analyses, repeatability and reproducibility of the SERS substrate preparation must be achieved since they are prerequisites to successfully validate the analysis method. This unfortunately remains an exception in the field. Consequently, this thesis was dedicated to the investigation of easily implementable strategies to conduct SERS analyses in biological matrices. To guarantee simple method transposal, these strategies essentially made use of suspensions of chemically reduced nanoparticles, which represent the most straightforward and economical SERS substrates. Dopamine was selected as analyte, given its great SERS activity and its involvement in several widespread diseases (e.g. Parkinson’s disease, schizophrenia, addictions). The resulting matrix was the complete culture medium of a model cell line used to study dopamine secretion, namely rat phaeochromocytoma PC-12 cells. A major issue was experienced all thesis long, the protein corona. This corona consists of a layer of proteins that coats the surface of the SERS substrates, preventing nanoparticles aggregation, thus hot-spot formation, and that competes with analytes for the surface of the SERS substrate. As a result, this work focussed on solving protein coronarelated problems. First and foremost, after having identified gold nanoparticles (AuNPs) as the most suitable SERS substrate for dopamine detection, the transfer of their synthesis protocol was assessed between two laboratories. Despite the use of different laboratory hardware, an exhaustive characterisation of the synthesised AuNPs demonstrated that the synthesis protocol could be successfully transferred, providing that critical parameters are under control. Then, a first strategy was established for the quantification of dopamine in cell culture media through colloidal AuNPs. It was based on the pre-aggregation of the colloid before adding the matrix, in order to circumvent the stabilisation issue brought about by the protein corona. The optimal proportions of reagents, determined by experimental design, enabled dopamine quantification from 0.5 to 50 ppm (2.64 – 264 µM) in the culture medium of PC-12 cells. The specificity of the method towards dopamine was also demonstrated and the exocytosis process of dopamine in PC-12 cells could be studied with the developed methodology. A preliminary study was afterwards carried out to investigate whether it was possible to increase the sensitivity and the specificity of dopamine detection with smartly functionalised AuNPs. A dual-mode SERS and fluorescence aptasensor was ergo imagined to benefit from both techniques advantages and its synthesis and sample preparation were optimised. The binding of dopamine to its specific aptamer was confirmed by surface plasmon resonance spectroscopy. Nonetheless, the determination of dopamine in a phosphate buffer by fluorescence lacked sensitivity, with an approximate limit of detection of 12.5 ppm (65.9 µM). Dopamine determination by SERS was also tricky because of the complex and noisy spectra obtained. Another solution to the protein corona stabilisation problem lay in the use of solid SERS substrates, since hot-spots naturally occur in this kind of substrates. The performances of three classes of solid SERS substrates were compared, in terms of dopamine detection in culture medium, of immersion resistance and of biocompatibility. Unlike substrates prepared by advanced physical technologies, polymeric substrates entrapping NPs were able to quantify dopamine in complex matrices. However, cells could not be cultured on these substrates due to a lack of cellular adhesion. The last kind of substrate investigated, glass coated with poly-L-lysine and AuNPs, was biocompatible. Still, dopamine determination in biological matrices was hampered due to protein surface fouling. This is why an original device capable of removing proteins from the analysed medium was developed. It derived from the use of ultracentrifugation membranes as effective protein retaining element between 2 compartments: the upper one containing the biological sample and the bottom one holding the SERS substrate and a clean collection medium like phosphate buffer. After the investigation of the acquisition and configuration parameters, the device was successfully applied to real-time monitoring. Gradually adding sample complexity, the diffusion process of a SERS label, 2-mercaptopyridine, followed by that of a neurotransmitter, serotonin, were first tracked. The distinction between highly and weakly metastatic pancreatic ductal adenocarcinoma cells was afterwards examined with the device. Based on differential metabolic metabolites production rates, discrimination between both cell types could be established. Finally, some clues were given about surface functionalisation important features. It was indeed noticed during this work that parameters such as the label nature and concentration, the solvent, the pH or the preservation conditions of the label solutions could impact the intensity and band position in SERS spectra. In conclusion, the results expounded in this thesis clearly confirm the potential of SERS for bioanalyses. Even so, remaining challenges will need to be taken up to see clinical applications of SERS methods flourishing. Achieving reproducible and efficient SERS substrates preparation and specifically attracting the analytes onto their surface are examples of such challenges to be risen. [less ▲]

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See detailMarine benthic hypoxia and its consequences for sediment-water exchanges and early diagenesis
Plante, Audrey ULiege

Doctoral thesis (2020)

The northwestern (NW) continental shelf of the Black Sea undergoes seasonal hypoxia. The benthic environment, the exchanges at the water-sediment interface and the diagenetic reactions are influenced by ... [more ▼]

The northwestern (NW) continental shelf of the Black Sea undergoes seasonal hypoxia. The benthic environment, the exchanges at the water-sediment interface and the diagenetic reactions are influenced by this phenomenon. In the framework of the BENTHOX project, two field cruises were conducted on the shelf in spring 2016 and in summer 2017. The first part of this investigation concerned the study of the impact of low oxygen levels in bottom waters on the diagenetic reactions. The microprofilings of geochemical parameters and the flux measurements showed both spatial and temporal variabilities in the benthic compartment of the NW continental shelf for the two seasons studied. The areas closest to the coasts exhibited the most important fluxes of oxygen consumption and of sulfate. These regions were strongly influenced by riverine inputs inducing a higher productivity and in turn resulting in an increase in the fluxes of organic matter deposited on the seabed. The diagenetic reactions were impacted by seasonal deoxygenation in bottom waters. The oxic respiration was less important in the summer as reflected by the shallower penetration depth of dissolved oxygen. Since 1995, the diffusive oxygen uptake (DOU) reported during hypoxic period indicated that the concentration of dissolved oxygen played an important role in the benthic exchange fluxes. Furthermore, a shallower reduction of sulphate and of Mn- and Fe-oxides observed in the sediments evidenced the impact of low oxygen levels on the diagenetic cascade. As a consequence, the benthic mineralization of organic matter was affected. During summer 2017, the oxic mineralization of organic carbon was less important and the contribution of the reducing species to oxygen consumption increased. The anaerobic mineralization of organic matter became thus the dominant process during the period of deoxygenation. The second part concerned the study of the sulfur and iron cycling in the shelf sediments during the low oxygen event of summer 2017. The sediments from the station close to the mouth of the Danube and that near the Dnieper exhibited a signature of detrital material different from that of the upper crust. The inputs of organic matter, in particular transported by the rivers, could influence the signal. The sediments of the NW shelf investigated were however of marine origin. Following the sulfate reduction already observed and mentioned above, the hydrogen sulfides produced were rapidly consumed as suggested by the low concentrations of acid volatile sulfide (AVS) and of the dissolved sulfide. The presence of pyrite in the upper layers of the sediments close to the water-sediment interface was plausible because the formation of pyrite in the water column had been reported due to the higher resistance of pyrite to oxidation compared to AVS (Wijsman et al. 2001). A non steady-state deposition was observed as suggested by Wijsman et al. (1999). It was characterized by an abrupt drop in the pyrite content caused possibly by fluctuations in salinity, dissolved O2 concentrations and organic matter fluxes. The non-reactive iron constituted the principal fraction of the total iron present in the sediments. Its contribution fell in the range reported for the marine sediments of the continental margins. A spatial variation of the concentration of highly reactive iron was nevertheless observed. Near the Dnieper mouth, the contents of reactive iron were lower and could be attributed to the less important fluvial inputs, to the sorption and/or precipitation processes or yet to the reallocation of the reactive iron of the shelf deposits towards the sediments in deep and euxinic waters. The last part of this thesis concerned the biogeochemistry of metals (Fe, Mn, Zn, Cu, Ni, Hg, Co and Cd) during the early diagenesis and the assessment of enrichment and pollution of these metals in the sediments of the shelf. The results showed that trace metals are probably linked to iron and manganese oxides as well as to sulphides. Ni and Zn could be involved in adsorption onto and co-precipitation with Fe- and Mn-oxides. Cu seemed to be associated preferentially to sulphides but no clear correlation was found. The enrichment and pollution of these metals in the shelf sediments showed spatial variability. The Danube delta area was enriched in Ni, Cu and Zn while the Odessa region was enriched in Co and Cd. The pollution of shelf sediments ranged from “unpolluted” to “very highly polluted”. Since the late 20th century, the heavy metal contents in shelf sediments remained stable in the Odessa region but increased in the Danube delta area. [less ▲]

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See detailEtat de santé des détenus en milieu carcéral: cas de la Prison Centrale de Mbujimayi
Kalonji, Muasa Patoka ULiege

Doctoral thesis (2020)

Cette thèse tend à identifier les problèmes de santé de la population pénitentiaire de la prison centrale de Mbujimayi. Elle tente de démontrer que les milieux pénitenciers restent moins salubres et ... [more ▼]

Cette thèse tend à identifier les problèmes de santé de la population pénitentiaire de la prison centrale de Mbujimayi. Elle tente de démontrer que les milieux pénitenciers restent moins salubres et favorisent la contamination des maladies. Les conditions d’hygiène restent précaires et exposent les détenus aux potentielles maladies infectieuses. Les décès qui ont été enregistrés à la prison avaient pour origine le manque d’une alimentation adéquate, le manque d’une pratique de dépistage et les conditions de détention précaires dans un espace très exigu. A ce tableau vient s’ajouter une surpopulation carcérale, trois fois supérieure à la construction du départ. Les cellules dortoirs qui étaient pour dix personnes sont devenues de plus de cinquante personnes. L’accessibilité aux soins de santé reste un problème tant que le patient n’a pas en retour ce qu’il attend des soignants. Le personnel de santé est présent sans moyens pour administrer convenablement les soins de santé aux patients détenus. Le détenu qui se trouve dans un état d’indulgence est incapable de survenir à ses besoins les plus élémentaires, ajouter à celui de se faire soigner et faire face aux frais qu’exigent la procédure de la justice, tout cela ne fait qu’aggraver son état de santé. La perception négative de leur vécu carcéral est révélatrice d’un mauvais traitement qui contraint les détenus à vivre dans l’indignité. Cette dissertation plaide pour que les responsables sanitaires au plus haut niveau prennent en charge la santé des prisonniers et garantissent un traitement humain. Une bonne législation sanitaire devrait garantir une détention digne. [less ▲]

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See detailCharacterization of Vietnamese microalgae strains for aquaculture wastewater treatment and biomass valorization
Luu Thao Nguyen, ULiege

Doctoral thesis (2020)

The study aims to isolate microalgal strains from shrimp – farm wastewater and select some of them suitable for production of biomass, biodiesel and other valuable products. We have isolated 4 isolates ... [more ▼]

The study aims to isolate microalgal strains from shrimp – farm wastewater and select some of them suitable for production of biomass, biodiesel and other valuable products. We have isolated 4 isolates, namely NL3, NL4, NL6 and NL12. The four isolates were preliminarily identified using molecular techniques based on partial sequence of 18S rRNA gene and classified into four different genera belonging to two phyla, Desmodesmus, Chlorella, Nannochloris (Chlorophyta) and Nannochloropsis (Eustigmatophyta). They were subjected to characterization in terms of growth, protein content, pigment and fatty acid content and profiles. As a result, isolates NL3 and NL6 were chosen for the project. The two strains were further identified based on the whole sequence of 18S rDNA – ITS1-5.8S-ITS2. Isolate NL3 was identified as Desmodesmus sp. NL3, which is proposed to be a new species with two group I introns (S516 and S1046) while isolate nl6 was 100% identical to Nannochloropsis salina (D12, accession number JX185299.1) from Shandong in China, so named Nannochloropsis salina NL6. Those two strains were further characterized in terms of growth, protein, pigment, fatty acid profiles and salinity tolerance (10‰, 20‰, 30‰ and 35‰). The two strains are tolerant to the different salinities studied. Nannochloropsis salina NL6 was characterized by a high percentage of fatty acids (40% DW at the end of exponential phase) and a fatty acid profile suitable for biodiesel production. Desmodesmus sp. NL3 was characterized by high protein (40% DW), biomass (1.54 g/L), and lutein (7 mg/g DW) contents at the end of the exponential phase. Notably, Nannochloropsis salina NL6 (N. salina NL6) was able to produce eicosapentaenoic acid (EPA) and astaxanthin. Their performance on the production of these compounds did not change much across the four salinities. The two strains, therefore, fit the project goals. [less ▲]

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See detailTemperature-induced sex reversal in Nile tilapia (Oreochromis niloticus): consequences on the brain, behavior and sound production
Dussenne, Mélanie ULiege

Doctoral thesis (2020)

As opposed to the fixed mechanism of sex determination of endotherms, the sex determination system of poikilotherms is variable and can depend (partially or totally) on environmental parameters, mainly ... [more ▼]

As opposed to the fixed mechanism of sex determination of endotherms, the sex determination system of poikilotherms is variable and can depend (partially or totally) on environmental parameters, mainly temperature. In fish, high temperature generally drives masculinization of the progenies independently from their genotype, creating individuals presenting a mismatch between their genotype and phenotype. Nile tilapia (Oreochromis niloticus) is a cichlid species presenting a male heterogamety (XY/XX). If temperature is superior to 32°C during the period of sex differentiation, genetic XX progenies are masculinized into XX “neomales”. In adulthood, these neomales sire 100% female progenies that can in turn be masculinized if temperature allows so. This process is naturally relevant, as neomales have been described in the wild. Indeed, climate change could increase the frequency of sex reversals, eventually leading to the decline of a population. As Nile tilapia is a species of high value in aquaculture, sex reversal has been investigated mainly through hormonal treatments. Consequently, few data are available on temperature-induced sex reversed individuals and the consequences in adulthood are unknown. This thesis aimed at determining the consequences of temperature-induced sex reversal via two main axes of research whose goals were to: 1. Investigate the influence of sex reversal on testis maturation and physiology, and on two neuronal populations: the gonadotropin-releasing hormone (GnRH) neuron population and the arginine-vasotocin (AVT) neurons populations (each divided into three subpopulations). These were specifically chosen because they are sexually different and are implicated in the regulation of socio- sexual behaviors. We found that neomales present a reduced number of GnRH1 neurons compared to both XY males and females. Surprisingly though, neomales present the same characteristics regarding testis maturation and hormone secretion (testosterone, 11-ketotestosterone, 17β-estradiol) as XY males. As GnRH1 neurons stand at the apex of the hypothalamo-pituitary-gonadal (HPG) axis, we formulated several hypotheses regarding a potential compensation mechanism that could take place at the three functional levels of this HPG axis. Neomales also presented differences in the number and area of AVT neurons compared to XY males and females, which we hypothesized to be linked with an increased risk to adopt a subordinate behavior, probably reflected in high cortisol circulating concentrations. 2. Investigate the consequences of sex reversal on behavior. The hypothesis regarding neomales subordination could be directly tested. We compared the behavior of neomales and XY males in agonistic interactions, as well as other parameters (size of the nest, hormone concentration, sound production). During dyadic confrontations, neomales present a higher aggression level compared to iii XY males, but almost always end up being subordinate. In this context, sound production seemed unnecessary. We also investigated if neomales were as attractive as XY males for gravid females. These females do not prefer any type of male, even though neomales are once again extremely aggressive. When next to a female, both male types emitted sounds that differed in duration and number of pulses. Surprisingly, no difference could be detected regarding hormone circulating concentrations (testosterone, 11-ketotestosterone, cortisol) in both contexts between the two male types. Interestingly, neomales were found to build smaller nests than XY males only when housed with a XY male. Overall, our results suggest that the sex chromosomes and/or the sex reversal procedure impacted the brain of neomales in a long-lasting manner. Neomales, presenting different brain characteristics than XY males in a region implicated in the integration and treatment of various internal/external informations, would react differently than XY males to the same stimuli. [less ▲]

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See detailSocial sustainability assessment in the biobased economy
Rafiaani, Parisa ULiege

Doctoral thesis (2020)

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See detailTopology Optimization Including Additive Manufacturing Constraints
Fernandez Sanchez, Eduardo Felipe ULiege

Doctoral thesis (2020)

The development of new materials and new manufacturing techniques have experienced a rapid development in the past few decades, and today designers have access to a large set of processes and materials to ... [more ▼]

The development of new materials and new manufacturing techniques have experienced a rapid development in the past few decades, and today designers have access to a large set of processes and materials to fabricate their designs. However, the conventional trial-and-error or other empirical design methods have become cumbersome and inefficient, while technological design tools such as topology optimization have become a breakthrough in design. Topology optimization supports the structural design by generating innovative concepts with high performance to weight ratio. The design tool usually proposes highly complex geometries that are difficult or even impossible to manufacture by conventional manufacturing processes. Fortunately, new Additive Manufacturing (AM) techniques provide a greater free-form freedom and enable the production of highly efficient, yet complex, optimized designs. Nonetheless, even the most advanced AM processes have their technological limitations. For instance, it is difficult to print parts with very small details or very large dimensions. It is also difficult to print parts with insufficient mechanical support during the layer-by-layer deposition process. Likewise, processes that deposit large volumes of material present difficulties related to the deposition path. This thesis introduces manufacturing constraints in density-based topology optimization in order to improve the manufacturability of the optimized designs. Specifically, geometrical restrictions are addressed aiming at imposing minimum member size, minimum cavity size, maximum member size, minimum separation distance between solid members, and minimum part inclination to reduce the use of sacrificial support material. The minimum size of the parts is imposed through filtering techniques. The maximum size is controlled using local volume restrictions, which are gathered into a single global constraint using aggregation functions. The minimum gap between solid members is also imposed through local volume restrictions, but these are applied in regions whose geometry enables to control the separation distance between parts and not their maximum size. The minimum inclination of the parts is imposed through local constraints that compare the surface slope with a critical baseline. The research is conducted within the density-based topology optimization framework and implemented in open-access codes suitable for solving 2D and 3D large-scale design problems. The assessed constraints demonstrate the ability to influence directly and indirectly the components manufacturability. For example, it is noted that the maximum size restriction can be used to address some limitations of processes depositing large volumes of material, such as the Wire Arc Additive Manufacturing (WAAM). In addition, the proposed methods show the ability to produce solutions with low amounts of intermediate densities and well-defined surfaces, which facilitates the interpretation and manufacture of the optimized designs. In particular cases, designs may feature such reduced complexity that they can even be manufactured by conventional manufacturing processes. [less ▲]

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See detailInvestigating the effects of plants and their root exudates on PAHs bioaccessibility to soil microorganisms and their impact on aged-contaminated brownfields remediation.
Davin, Marie ULiege

Doctoral thesis (2020)

In Wallonia, there are 6,000 estimated brownfields (rising to over 3.5 million in Europe) that require remediation. Polycyclic aromatic hydrocarbons (PAHs) are persistent organic compounds of major ... [more ▼]

In Wallonia, there are 6,000 estimated brownfields (rising to over 3.5 million in Europe) that require remediation. Polycyclic aromatic hydrocarbons (PAHs) are persistent organic compounds of major concern that tend to accumulate in the environment, threatening ecosystems and health. They represent 17% of all encountered pollutants. The thesis, articulated around several axes, focused on improving less aggressive PAHs remediation techniques in brownfields, such as bioremediation and phytoremediation, as alternatives to environmentally aggressive, expensive and often disruptive current soil remediation strategies. More specifically, it was built on several authors' observation that PAHs soil contents decrease in the presence of plants. The hypothesis was made that this could be related to the production of plant root exudates. A bioaccessibility measurement protocol was adapted to two brownfield soils using Tenax® beads in order to compare PAHs bioaccessibility in soil samples. In both experimental soils, PAHs desorption kinetics were established, described by site distribution models, and common extraction times were calculated (respectively 48 h and 24 h for both experimental soils). The potential of saponin (a natural surfactant) as extracting agent and as a bioremediation enhancer on an aged-contaminated soil was investigated. In a first experiment, soil samples were extracted with saponin solutions (0; 1; 2; 4 and 8 g L-1). In a second experiment conducted in microcosms (28°C), soil samples were incubated for 14 or 28 days in presence of saponin (0; 2.5 and 5 mg g-1 DW). CO2 emissions were monitored throughout the experiment. After the incubation, dehydrogenase activity was measured as an indicator of microbiological activity, and the bioaccessible and residual PAHs contents were determined. The 4 g L-1 saponin solution globally extracted significantly more PAHs than water. Neither PAHs dissipation nor bioaccessibility were enhanced in presence of saponin compared to control samples after 28 days. However, CO2 emissions and dehydrogenase activities were significantly more important in presence of saponin, suggesting no toxic effect of this surfactant towards soil microbiota. The role of two Fabaceae (Medicago sativa L. or Trifolium pratense L.) root exudates in enhancing PAHs bioaccessibility and dissipation in an aged-contaminated soil was investigated during an incubation experiment (28°C). The CO2 emissions were significantly higher in presence of T. pratense exudates; the dehydrogenase activities (measured after 14 and 28 days) showed improvements of the soil microbial activity in presence of both types of root exudates compared to untreated soil samples; the PAHs residual contents decreased more in untreated samples than in the presence of T. pratense exudates; and M. sativa exudates lowered PAHs bioaccessibility but not residual contents. The effects of Medicago sativa L. and Trifolium pratense L. on the PAHs’ bioaccessibility and dissipation in an aged-contaminated soil throughout a rhizoremediation trial were investigated. The bioaccessible and residual PAH contents were quantified after three, six and twelve months of culture. The rhizoremediation results show that M. sativa developed better than T. pratense on the contaminated soil. When plants were absent (control) or small (T. pratense), the global PAHs’ residual contents dissipated from the rhizosphere to 8% and 10% of the total initial content, respectively; in the presence of M. sativa, dissipation after 12 months was only 50% of the total initial content; and the PAHs bioaccessible content increased more significantly in the absence of plants. Finally, a review of three scientific trends that lead PAHs contaminated soils/sediments remediation studies and management was conducted. (i) The choice of PAHs compounds that are being studied and targeted in scientific literature were discussed, and it was suggested that the classical 16 PAHs from the American Environmental Protection Agency’s (US-EPA) watch list might no longer be sufficient to meet actual environmental challenges. (ii) The choice of experimental material in remediation studies was discussed. Bibliometric measures were used to show the lack of PAHs remediation trials based on co-contaminated or aged-contaminated material. (iii) The systematic use of the recently validated bioaccessibility measurement protocol (ISO/TS 16751:2018) in remediation trials was discussed, and it was suggested that such measurement should be implemented as a tool to improve remediation processes and management strategies. [less ▲]

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See detailDétection et caractérisation d'exoplanètes en transit avec le télescope TRAPPIST-Nord
Barkaoui, Khalid ULiege

Doctoral thesis (2020)

À ce jour, la majorité des exoplanètes découvertes transitent leurs étoiles-hôtes. Une petite partie de ces exoplanètes en transit sont de type Jupiter-chaud en orbite autour d'étoiles de type solaire ... [more ▼]

À ce jour, la majorité des exoplanètes découvertes transitent leurs étoiles-hôtes. Une petite partie de ces exoplanètes en transit sont de type Jupiter-chaud en orbite autour d'étoiles de type solaire. Malgré le fait que ce type d'exoplanètes ont été étudiées depuis plusieurs décennies, les Jupiters-chauds sont toujours des cibles extrêmement intéressantes qui nous permettent d'étudier les mécanismes de formation et d'évolution planétaires, grâce à ses fortes irradiations, et ses champs gravitationnel et magnétique intenses. Environ 280 Jupiters-chauds sont connus à ce jour. Le nombre d'exoplanètes en orbite autour des étoiles ultra-froides est encore petit (7 planètes à ce jour). Les étoiles ultra-froides (UCDs) sont des étoiles plus petites (0.08R_⨀ < R < 0.15R_⨀), moins massives (0.075M_⨀ < M < 0.1M_⨀) et plus froides (température effective inférieure à 2700K) que le Soleil. Ces exoplanètes pourraient nous fournir une opportunité pour étudier leurs propriétés atmosphériques avec les futurs observatoires, tels que le télescope spatial James Webb de la NASA (JWST) et le télescope géant européen (E-ELT). Au cours de la préparation de ma thèse, j'ai participé à la détection et la caractérisation de nouvelles exoplanètes de type Jupiter-chaud éclipsant des étoiles de type solaire dans le cadre de plusieurs projets à grand champ, tels que WASP (Wide Angle Search for Planet), QES (Qatar Exoplanet Survey) et GPX (Galactic Plane eXoplanets surveys), et les missions spatiales Kepler et TESS (Transiting Exoplanet Survey Satellite) de la NASA. J'ai participé également à la recherche d'exoplanètes telluriques en transit devant d'étoiles ultra-froides du voisinage solaire dans le cadre du projet SPECULOOS (Search for habitable Planets EClipsing Ultra-cOOl Stars). Une partie de ma thèse a été consacrée au projet SPECULOOS. J'ai suivi la photométrie d'une cinquantaine de cibles SPECULOOS en utilisant TRAPPIST-Nord. Ce dernier est un télescope robotique de 60 cm de diamètre situé à l'observatoire de l'Oukaimeden. J'ai participé à l'installation du télescope TRAPPIST-Nord à l'observatoire de l'Oukaimeden en mais 2016, et j'ai effectué plusieurs missions de la maintenance du TRAPPIST-Nord. J'ai observé 54 cibles SPECULOOS dont TRAPPIST-1. Plusieurs cibles se révèlent calmes en photométrie, ce qui rende plus facile l'éventuelle détection d'un transit planétaire. Quelques cibles montrent des "flares" (variations importantes de flux dans quelques minutes, induites par des phénomènes de reconnexion magnétique dans les atmosphères stellaires). Finalement, quelques cibles montrent une variabilité complexe (modulation de quelques % d'amplitude), probablement induite par la rotation de l'étoile, la présence de tâches ou de nuages dans la photosphère de ces étoiles. J'ai utilisé les courbes de lumière de cibles SPECULOOS acquises par TRAPPIST-Nord pour estimer leur sensibilité en termes de tailles de planètes détectables. J'ai analysé les données de 49 cibles SPECULOOS. Le résultat démontre bien que TRAPPIST-Nord est capable de détecter des transits de planète de taille similaire à la terre en orbite autour d'étoiles ultra-froides proches. De plus, j'ai contribué à la découverte de sept planètes telluriques tempérées en orbite autour d'une étoile naine ultra-froide plus proche baptisée TRAPPIST-1. Ces planètes ont des tailles comparables à celle de la Terre et dont trois située dans la zone habitable autour de TRAPPIST-1. Les six planètes internes forment une chaîne quasi résonante. Ces planètes sont des cibles potentielles pour la caractérisation atmosphérique à l'aide de futur télescope JWST. J'ai participé au suivi photométrique du système TRAPPIST-1 avec TRAPPIST-Nord entre juin 2016 et juin 2020 pour un total de 410 heures d'observations. J'ai effectué la réduction des données et la photométrie à l'aide du pipeline semi-automatique TRAPPHOT développé sous IRAF et j'ai effectué l'analyse des courbes des transits en utilisant la technique de Monte Carlo par chaînes de Markov (MCMC). Les résultats obtenus sont en bon accord avec ceux obtenus avec le télescope spatial Spitzer de la NASA. Les timings des transits obtenus avec TRAPPIST-Nord vont permettre d'améliorer la précision de la mesure des masses et des densités de ces planètes en utilisant la méthode de TTV (Transit-Timing Variation). L'autre partie de ma thèse a été consacrée au suivi photométrique avec TRAPPIST-Nord de candidats exoplanètes produits par les surveys à grands champs WASP, QES, GPX, Kepler K2 et TESS. Ces observations ont notamment contribué à la confirmation et à la caractérisation d'exoplanètes en transit. J'ai contribué à la découverte de 12 nouvelles exoplanètes de type Jupiter-chaud dans le cadre du projet WASP. Parmi ces 12 exoplanètes se trouvent WASP-161b, WASP-163b et WASP-170b présentées dans mon premier article. WASP-161b orbite autour d'une étoile de type spectral F6V et de magnitude Vmag = 11.1 sur une orbite de 5.41 jours, et elle a une masse de 2.5 M_Jup et un rayon de 1.14R_Jup. WASP-163b a une masse de 1.9 M_Jup et un rayon de 1.2R_Juporbite autour d'une étoile de type spectral G8V et de magnitude Vmag = 12.5 sur une orbite de 1.61 jours. WASP-170b (M_p=1.7 M_Jup et R_p=1.1 R_Jup) orbite autour de son étoile-hôte de type spectral G1V et de magnitude Vmag = 12.8 sur une orbite de 2.34 jours. Ces planètes sont larges et plus massives que Jupiter, et elles sont bien reproduisent par les modèles classiques de structure de planètes géantes fortement irradiées. J'ai participé au suivi photométrique du 16 candidats exoplanètes du projet QES, dont 3 confirmés comme des planètes. Parmi ces 3 exoplanètes se trouve Qatar-10b. Cette dernière est une planète de type Jupiter-chaud en orbite autour d'une étoile de type spectral F7V et de magnitude Vmag=12.8. Sa période orbitale est de 1.65 jours, sa masse est de 〖0.74 M〗_Jup et son rayon est de 1.53 R_Jup. J'ai participé également au suivi photométrique des candidats exoplanètes des missions spatiales Kepler et TESS de la NASA. J'ai observé sept candidats exoplanètes Kepler, dont l'un des candidats a été confirmé comme planète, EPIC_206061524.01. C'est une planète de type Neptune de rayon ~6.92 R_⨁ et de température d'équilibre 660 K sur une orbite de 5.88 jours autour d'une étoile de type spectral K7V et de Vmag =14.89. J'ai contribué aussi à la découverte d'un nouveau système planétaire découvert par la mission TESS autour de l'étoile TOI-732. Celle-ci est une étoile de type spectral M3.5V, de magnitude Vmag=13.14 et de température effective T_eff= 3360K. TOI-732.01 est une planète de type Terre de masse M_p=2.34M_⊕ et de rayon R_p= 1.35R_⨁, sur une orbite de 0.77 jour autour de son étoile. TOI-732.02 est une planète de type sous-Neptune (M_p= 6.29M_⊕ et R_p= 2.42R_⊕) sur une orbite de 12.25 jour autour de son étoile. J'ai également participé au suivi photométrique de deux systèmes binaires à éclipses dans le cadre de projet GPX. GPX-TF16E-18, qui se compose d'une étoile naine blanche de masse M_1= 0.72M_⨀, de rayon R_1= 0.013R_⨀ et de température effective T_eff= 8700K$, et d'une étoile de la séquence principale de type spectral K7, de masse M_2= 0.64M_⨀, de rayon R_2= 0.65R_⨀ et de température effective T_eff= 4070K. La naine blanche tourne autour de cette sur une très courte période de 0.298 jour. GPX-1b est une naine brune de masse de 19.6M_Jup et de rayon de 1.46R_Jup sur une orbite de 1.74 jours autour d'une étoile de type spectral F et de magnitude Vmag=12.3. [less ▲]

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See detailWorking mechanisms of inulin concerning intestinal mucosal immunity and microbiota in chickens infected with Salmonella Enteritidis
Song, Jiao ULiege

Doctoral thesis (2020)

Salmonella, one of the most common foodborne pathogens, is a concern for human health, contaminates poultry and egg products, and causes huge economic losses to the poultry industry. The gut of chicken ... [more ▼]

Salmonella, one of the most common foodborne pathogens, is a concern for human health, contaminates poultry and egg products, and causes huge economic losses to the poultry industry. The gut of chicken contains mechanical, immune, chemical, and microbial barriers, and is an important digestive, immune, and endocrine organ. Salmonella Enteritidis (SE) damages the intestinal epithelial cells structure, mucosal immunity, and microbial composition. Because of the emergence of antibiotic resistance, the development of dietary alternative strategies to reduce the susceptibility of SE colonization should be a priority. It has been previously concluded that prebiotics, such as inulin, can improve the overall health by providing an intestinal environment that is unfavourable for foodborne pathogens such as Salmonella. The aims of the research described in this thesis are to (1) select an optimal inulin supplementation dosage that optimizes the intestinal mucosal morphology and immune status of specific pathogen-free (SPF) chickens; (2) investigate whether optimal inulin supplementation dosage improve the mechanical, immune, and chemical barriers in JAK–STAT signalling in intestinal mucosal tissue at 1 and 3 days post-infection (dpi) in SE-infected SPF chickens; and (3) investigate whether inulin alter the microbial composition and function of SE-infected SPF chickens. In the first trial, we determined the optimum level of inulin supplementation for effectiveness in the gut. The mucosal morphology and immune indexes of SPF chickens that fed a basal diet supplemented with 0, 0.25, 0.5, 1.0, or 2.0% inulin were analyzed on days 7, 14, and 21, respectively. The results showed that the SCFA concentrations in the cecum and serum were increased by dietary inulin supplementation at 21 d. The mucosal morphology was improved in the duodenum and ileum of SPF chickens fed inulin. Also, inulin at a low concentration (0.25% or 0.5%) significantly decreased the gene expression of NF-κB and LITAF at 7, 14, and 21 d, and of IL-6 and iNOS at 7 and 14 d; and increased that of MUC2 and claudin-1 in the ileum of SPF chickens at 7, 14, and 21 d. The results indicated that the effects of inulin on mucosal immune function occurred in a dose-dependent manner. A low inulin concentration (0.25% or 0.5%) may be beneficial in promoting intestinal immune function. In the second trial, we investigated whether and how inulin administration influenced the intestinal barrier function and mucosal immunity with SE infection. A control group (CON) chicken fed a basal diet and three SE-infected groups fed a basal diet supplemented with inulin 0% (SE), 0.5% (0.5% InSE), and 1% (1% InSE), respectively. Until 28 d of addition, chickens in the four groups were orally infected with SE or vehicle (phosphate-buffered saline). The SE challenge significantly increased the mucosal gene expression of proinflammatory cytokines and serum concentrations of antibodies, but significantly decreased the gene expression of MUC2 and claudin-1 compared with the CON group. However, Inulin supplementation reversed these gene expression and relieved the injury of duodenum, jejunum, and ileum at 1 and 3 dpi within the SE-challenged groups. The SE challenge significantly increased ileal protein expression of p-STAT3 and JAK1 at 3 dpi compared with the CON group, while inulin supplementation suppressed p-STAT3 and JAK1 protein expression at 3 dpi compared with the SE group. The results showed that inulin alleviated SE-induced gut injury by decreasing the pro-inflammatory response and enhancing mucosal immunity in chickens. In the third trial, the impact of inulin on SCFAs, microbial composition, and microbiome functions of SPF chickens infected with SE were investigated. The SE infection led to significantly decreased cecal butyrate concentrations compared with the CON group, and inulin supplementation reversed these changes. SE infection significantly decreased the alpha diversity, while inulin supplementation significantly increased the alpha diversity and richness. At the phylum level, Inulin addition at 1% increased abundance of Firmicutes and decreased abundance of Bacteroidetes compared with the SE group according to the Student’s t-test. The correlations of the microbiota genera with metabolite SCFA contents showed that SCFA-producing bacteria had positive correlations with acetate and butyrate contents. Analysis of the functional capacity in cecal microbiome at pathway level 2 showed that inulin supplementation at 0.5% and 1% reversed the abundance of KEGG pathways and KOs in SE infected chickens. In short, SE infection decreased the alpha diversity of cecum microbiota and SCFA contents, and accordingly increased the abundance of KEGG pathways and KOs related to nutritional and energy metabolism, whereas inulin addition reversed these changes and had inhibitory effects on SE infection. The results of the above three experiments indicate that SE caused the rapid induction of pro-inflammatory cytokines and changes in gut morphology, gut microbiome, microbial functional activities, and SCFA production, which resulted in activation and normalization of the immune system in the bird’s early life. However, the intestinal parameters and SCFA concentration were altered by inulin in a dose-dependent manner. The 0.5% inulin relieved the intestinal inflammatory environment and injury induced by SE infection through the JAK–STAT signaling pathway and the changes of SCFA-producing bacteria composition and function. As a whole, these observations may lead to the development of novel prevention and control strategies of Gram-positive bacterial infections with prebiotic administration in chickens and may even be applicable to other animal species. Moreover, determining the role played by inulin in gut microbiota-driven pathways using metagenomics approaches further elucidated how prebiotics contribute to the gut microbiota combating pathogen infection. [less ▲]

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See detailEtude de la synthèse et du radiomarquage au fluor-18 de nanostructures à base de polyéthylène glycol
Kaisin, Geoffroy ULiege

Doctoral thesis (2020)

Nanoparticles display promising prospects as carriers of a therapeutic load in order to reduce the toxicity and increase the efficiency of medecines the use of which in a classical formulation can prove ... [more ▼]

Nanoparticles display promising prospects as carriers of a therapeutic load in order to reduce the toxicity and increase the efficiency of medecines the use of which in a classical formulation can prove problematical. A privileged field of application is oncology where chemotherapeutic agents too often go along with severe secondary effects. This opus is part of a global project aiming at studying the size dependant in vivo behaviour of radiolabelled nanoparticles by positron emission tomography. The understanding and control of their behaviour coupled with progress in molecular imaging are the keys of tomorrow’s personalized therapies. The first part of our work relates in detail our contribution to the synthesis of a hydrophilic monomer as a forerunner of micellar nanoparticles. The synthesis as originally reported in literature has been improved in three iterations so as to bring the global yield in alpha-mesyl-omega-cis-5-norbornene-exo-2,3-dicarboximide PEG from 1.2 % up to 87 %. The second part of this work is dedicated to the preparation of a copolymer and to the development of nanoparticles and their marking with fluor-18. The controlled copolymerizing of the hydrophilic monomer and of the hydrophobic monomer led to creating a dibloc amphiphilic polymer. The latter was then micellized and reticulated in order to shape functionalized nanoparticles with mesylate functions on the surface that can be moved by fluorine-18. In view of the obtained radiolabelling results, an alternative strategy, using a prosthetic group, 4-[18F]fluorobenzyl azide, has been put forward. In the third part of this work, we suggest an innovative method for the preparation of that synthon, based on an original reaction allowing direct conversion of 4-[18F]fluorobenzylic alcohol into 4-[18F]fluorobenzyl azide in five minutes’ time with a radiochemical purity of 84 %. [less ▲]

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See detailRadiosynthesis of 18F-labeled reagents for the 18F-difluoromethylation of heteroarenes
Lemos, Agostinho ULiege

Doctoral thesis (2020)

The reagent difluoromethyl benzothiazolyl-sulfone (1) has been extensively used in the difluoromethylation of substrates bearing C=C, C≡C, and C≡N bonds by visible light photoredox catalysis. Taking ... [more ▼]

The reagent difluoromethyl benzothiazolyl-sulfone (1) has been extensively used in the difluoromethylation of substrates bearing C=C, C≡C, and C≡N bonds by visible light photoredox catalysis. Taking advantage of the reactivity of 1 as difluoromethylating reagent, we intended to perform the radiosynthesis the 18F-labeled compound [18F]1 as a novel labeled compound for late-stage introduction of 18F-difluoromethyl groups. Low activity labeling experiments (150-200 MBq) were performed in order to determine the most suitable conditions for the synthesis of [18F]1. Our results showed that a two-step methodology consisting in the 18F-labeling of the precursor bromofluoromethyl benzothiazolyl-sulfide (4) and subsequent oxidation of the [18F]difluoromethyl benzothiazolyl-sulfide ([18F]2) afforded the cartridge-purified [18F]1 in higher radiochemical yield (RCY). The efficiency of the 18F-labeling reaction was influenced by the following parameters: (i) the type and amount of base and phase-transfer catalyst (PTC) used in the delivery of dry [18F]fluoride ([18F]F-); (ii) the solvent, the temperature, and the reaction time; (iii) the type and amount of 18F-labeling precursor. The amount of the oxidizing agent sodium (meta)periodate (NaIO4) and ruthenium (III) chloride hydrate (RuCl3·xH2O) had a significant impact on the oxidation of [18F]2. Having the optimal conditions in hand, the radiosynthesis of sulfone [18F]1 was fully automated on a GE FASTlabTM synthesizer in conjunction with a semi-preparative high performance liquid chromatography (HPLC) purification procedure. Starting with 120-135 GBq of [18F]fluoride, the sulfone [18F]1 was isolated in 4.5 ± 0.1% RCY [decay-corrected at the start of the synthesis (SOS)] and with a molar activity of 54 ± 7 GBq·μmol-1 at the end of the synthesis (EOS). Following up on the reported efficiency of the [18F]difluoromethyl benzothiazolyl-sulfone ([18F]1) as a 18F-difluoromethylating reagent, we investigated the influence of structurally-related [18F]difluoromethyl heteroaryl-sulfones in the reactivity toward the photoredox C–H 18F-difluoromethylation of heteroarenes under continuous-flow conditions. In the present work, six new [18F]difluoromethyl heteroaryl-sulfones [18F]5a–[18F]5f were prepared and, based on the overall radiochemical yields (RCYs), three of these reagents ([18F]5a, [18F]5c, and [18F]5f) were selected for the fully automated radiosynthesis on a FASTlabTM synthesizer (GE Healthcare) at high level of starting radioactivity. Subsequently, their efficiency as 18F-difluoromethylating reagents was evaluated using the antiherpetic drug acyclovir as a model substrate. Our results showed that the introduction of molecular modifications in the structure of [18F]1 influenced the amount of fac-IrIII(ppy)3 and the residence time needed to ensure a complete C–H 18F-difluoromethylation process. The photocatalytic C–H 18F-difluoromethylation reaction with the reagents [18F]5a, [18F]5c, and [18F]5f was extended to other heteroarenes. Radical-trapping experiments demonstrated the likely involvement of radical species in the C–H 18F-difluoromethylation process. [less ▲]

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See detailLire la peur dans leur jeu. Exploration du potentiel effrayant du texte dans le jeu vidéo
Surinx, François-Xavier ULiege

Master's dissertation (2020)

Au sein des play/game studies, le texte a souvent tendance à être négligé au profit de l'analyse de composantes plus spécifiques au médium (comme le gameplay) ou plus apparentes (comme les graphismes). Ce ... [more ▼]

Au sein des play/game studies, le texte a souvent tendance à être négligé au profit de l'analyse de composantes plus spécifiques au médium (comme le gameplay) ou plus apparentes (comme les graphismes). Ce mémoire a notamment pour but d'initier un premier pas dans la prise en compte du texte comme élément prépondérant au sein du jeu vidéo, cela en n'oubliant pas d'observer le cadre sémiotique complexe qui fait la spécificité du médium. Afin de montrer l'importance du texte, l'étude présente le rôle que celui-ci joue dans la suscitation de la peur chez le joueur. Après une introduction comprenant une redéfinition de ce qu'on peut entendre par jeu effrayant (car il apparait réducteur de se limiter au seul genre du survival horror) et un examen de la notion psychologique de peur, l'étude se centre sur une analyse d'exemples afin de valider le modèle proposé et de montrer la richesse des dispositifs de peur faisant intervenir le texte. [less ▲]

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See detailReliability of ESG ratings - A qualitative and quantitative assessment
Ruth, Jérôme ULiege

Master's dissertation (2020)

This thesis aims at studying the reliability of ratings through three complementary research questions. The first research question showed that, despite an overall agreement on the SRI definition, ESG ... [more ▼]

This thesis aims at studying the reliability of ratings through three complementary research questions. The first research question showed that, despite an overall agreement on the SRI definition, ESG rating is a relative concept specific to each agency as reflected by different methodologies and purposes. This indicates a possible complementary effect between agencies. The second research question confirmed a size and a location effect and provided indications of a learning effect. Build upon the result of the second research question, the third research question has shown that portfolios of high and low ESG ratings are neither associated with overperformance nor with underperformance. Besides, this question has shown that ESG ratings could not reproduce findings on specific pillar components (such as employees and customer satisfaction). [less ▲]

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See detailDerrière la différenciation du gameplay : définition et circonscription du jeu vidéo asymétrique.
Messina, Alexis ULiege

Master's dissertation (2020)

Multiplayer games sometimes offer the opportunity to witness, in a same game, a profound differentiation of playability. The asymmetrical video game, a videogame genre that has existed for a long time but ... [more ▼]

Multiplayer games sometimes offer the opportunity to witness, in a same game, a profound differentiation of playability. The asymmetrical video game, a videogame genre that has existed for a long time but has received a lot of media coverage in recent years, is becoming the research area for a phenomenon that has not yet been studied: the asymmetrization of gameplays. This concept involves the fact that several players have personalized starting conditions, and must perform different actions or accomplish different objectives. Although it is now widely understood that everyone plays the game in a different way and, as a result, is already living a profoundly singular experience (Henriot 1989, Genvo 2005), "differentiation of playability" remains a frequently used term. Its recurrence in the discourse of creators, the specialized press and gamers makes it a significant element whose foundations need to be questioned. This research aims, using a genre analysis methodology (Arsenault 2011, Montembeault & Deslongchamps-Gagnon 2019) and several structural (Neto 2016, Fullerton 2014, O'Donnell 2019, Harris, Hancock & Scott 2016) and discursive (Maingueneau & Amossy 2003, Maingueneau 2016) analysis grids, to define the characteristic elements of the asymmetrical genre in order to understand its essential component: the distinction of the game experience. This work comes to the conclusion that the asymmetrical video game can be considered as a videogame supergenre (Messina 2020), that is, a specialization of the multiplayer hypergenre in which many genres evolve through processes of gameplay dissymmetrization (Messina 2020). This master thesis also aims at developing a specialized vocabulary to refer to specific multiplayer video game design processes, while questioning their contexts of creation and use as communication objects. [less ▲]

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See detailLa fluorescence chlorophyllienne associée aux composés phénoliques des feuilles pour évaluer le statut azoté de la biomasse de la pomme de terre
Ben Abdallah, Feriel ULiege

Doctoral thesis (2020)

Interroger la plante pour en déterminer son statut azoté est la stratégie utilisée en cours de saison pour le raisonnement de la fertilisation azotée des cultures de plein champ. L’établissement d’une ... [more ▼]

Interroger la plante pour en déterminer son statut azoté est la stratégie utilisée en cours de saison pour le raisonnement de la fertilisation azotée des cultures de plein champ. L’établissement d’une méthode de référence permettant l’évaluation du statut azoté en culture de pommes de terre a nécessité d’établir, en première étape, la courbe critique de dilution de l’azote (N) en Belgique pour la variété Bintje et d’en déduire l’indice de nutrition azotée (INN). L’INN est l’indicateur de référence reconnu pour l’évaluation du statut azoté d’une culture en cours de saison. L’INN a permis de définir l’optimum azoté de la culture pour assurer la production et le maintien d’un couvert végétal optimal nécessaire à l’obtention du rendement maximum en tubercules. Cependant, cette méthode de référence est basée sur un échantillonnage intrusif et donc laborieux et consommateur de temps qui rend son application à l’échelle du champ difficile à mettre en œuvre. Dans ce cadre, des méthodes optiques rapides sont souvent utilisées en cours de saison culturale pour l’évaluation du statut azoté en culture de pommes de terre de plein champ. Afin de remédier aux limitations des méthodes optiques usuellement utilisées en plein champ et qui reposent sur l’estimation de la teneur en chlorophylle des feuilles (limitations liées à la saturation des mesures, au retard ou au défaut de détection par rapport à l’entrée réelle en carence azotée et au manque de spécificité des mesures vis-à-vis de l’N), une nouvelle approche a été étudiée pour l’évaluation du statut azoté en culture de pommes de terre. Cette approche est basée sur la signature de la fluorescence chlorophyllienne (ChlF) pour l’estimation de la teneur en composés phénoliques des feuilles, plus spécifiquement les flavonoïdes. Les potentialités des mesures de la ChlF des feuilles ont été évaluées par comparaison avec des mesures optiques sur le feuillage en cours de saison durant trois années (2012, 2013 et 2014) pour deux variétés de pommes de terre cultivées en Belgique (Bintje et Charlotte) et recevant des doses croissantes de fumure azotée. Les résultats indiquent que les mesures de ChlF basées sur l’estimation des flavonoïdes comme indicateurs foliaires du statut azoté de la culture, et combinés à la teneur en chlorophylle des feuilles, sont les plus pertinentes pour l’évaluation du statut azoté comparativement aux mesures de transmittance ou de réflectance. Les potentialités des mesures de la ChlF mises en évidence pour l’évaluation du statut azoté en culture de pommes de terre sont i) la sensibilité de réponse tout particulièrement en couplant les indicateurs flavonoïdes aux indicateurs chlorophylle, ii) la précocité de détection de la déficience en N (liée à l’accumulation des flavonoïdes suite à une déficience en N), et iii) l’exactitude (justesse et répétabilité) des mesures des indicateurs combinés pour l’évaluation de teneur en N au niveau de la plante. La principale limitation pointée au niveau de ce travail de recherche est la faible spécificité des indicateurs foliaires qui ne sont pas exclusivement reliés à la fourniture en N. Les indicateurs foliaires testés sont en effet sensibles à d’autres facteurs externes tels que la variété, l’année d’expérimentation et la date de mesure. En travaillant avec les valeurs relatives des mesures par la prise en compte d’une fenêtre de référence (soit une fenêtre sans apport d’N, soit une fenêtre surfertilisée), la limitation liée à la spécificité des mesures est atténuée comparativement aux valeurs absolues. Les mesures analytiques des feuilles de pommes de terre récoltées ont confirmé que la déficience en N induit l'accumulation des composés flavonoïdes foliaires et plus précisément de la sous-classe des flavonols. La teneur totale en flavonols mesurée pour Bintje, identifiée comme composée de la rutine, de la quercétine et du kaempférol-3-rutinoside, a été corrélée aux mesures de ChlF en relation avec le statut azoté de la culture. Cependant, l'identification et la quantification d'autres composés spécifiques de la sous-classe des flavonols dont l’accumulation est liée au statut azoté de la culture n’ont pas été possibles au niveau de ce travail de thèse, en particulier pour la variété Charlotte. En conclusion, les mesures de ChlF liées à l’estimation de la teneur en flavonoïdes (en particulier la sous-classe des flavonols) combinés à la teneur en chlorophylle sont prometteuses pour l’évaluation en cours de saison du statut azoté de la culture de pommes de terre. En raison de la faible spécificité tant de la chlorophylle que des flavonoïdes pour l’évaluation du statut azoté, il est préconisé pour la mise en œuvre de ces indicateurs de travailler avec les valeurs relatives des mesures plutôt qu’avec leurs valeurs absolues. [less ▲]

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See detailLa Contrainte ludique : de l'OuLiPo au jeu vidéo
Godfirnon, Maxime ULiege

Master's dissertation (2020)

This work proposes a general theory of game constraint, i.e. the voluntary addition of an additional rule structure to an initial game structure, making the game more difficult. Based on the definitions ... [more ▼]

This work proposes a general theory of game constraint, i.e. the voluntary addition of an additional rule structure to an initial game structure, making the game more difficult. Based on the definitions of the constrained literature by the Ouvroir de Littérature Potentielle (or OuLiPo) and game theorists, this research defines the notion of "playful constraint" before analyzing it in video games. Once a typology of classification and a method of analysis have been established, we consider the phenomena of institutionalization that can mark a constraint, the political dimensions that it can carry as well as the mechanism of creation of artworks that it can engender. [less ▲]

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See detailEffect of the type of clay earthen materials and substitution materials on the physico-mechanical properties and durability of compressed earth blocks
Nshimiyimana, Philbert ULiege

Doctoral thesis (2020)

Clay earthen materials are the most common building materials used all over the world for sustainable constructions. Today, the drastic increase of population and urbanization, especially in developing ... [more ▼]

Clay earthen materials are the most common building materials used all over the world for sustainable constructions. Today, the drastic increase of population and urbanization, especially in developing world, calls for better knowledge of earthen materials in the contemporary construction. The present thesis aimed to characterize the suitability of clay materials from four sites in the vicinity of Ouagadougou, Burkina Faso: Kamboinse, Pabre, Kossodo and Saaba for the production of stabilized compressed earth blocks (CEBs). The study also characterized by products of industry: calcium carbide residue (CCR) from Kossodo and agriculture: rice husk ash (RHA) from Bagré and Okra plant fibers from Kaya for the stabilization of CEBs. The characterizations were carried out on physico textural and chemico mineral properties. The study additionally tested the physico mechanical, hygro thermal and durability performances of CEBs stabilized with the by products for applications in building construction, specifically in the Sahelian climatic context. Mixtures were produced by addition of 0 25 wt% CCR, 10-25 wt% CCR:RHA (various ratios) and 0.2 1.2 wt% fibers to the earthen materials. The mixtures were used to produce the mix solutions and mold stabilized CEBs (295x140x95 mm3) by static compression (~35 bars), and cured in various conditions for 0 to 90 days. The results show that the clay materials from Pabre and Kossodo respectively contain the highest fraction of clay particles (20-30%) and gravel (40%). Saaba and Pabre respectively contain the highest fraction of kaolinite clay mineral (60 80%) and quartz (40 60%). Kamboinse contains the highest amount of exploitable deposit (700 000 m3), 10 25% clay particles and 40 75% kaolinite, while Kossodo contains medium fraction of kaolinite (35-50%). The CCR mainly contains portlandite (40 50 % hydrated lime: Ca(OH)2). The RHA is mainly amorphous, with pozzolanic reactivity. Saaba and Kossodo recorded the highest rate of pozzolanic reactivity with CCR, related to the high content and degree of poorly ordered kaolinite. Pabre and Kamboinse recorded the lowest rate of reactivity. With respect to unstabilized CEBs (0 % CCR), the compressive strength of CEBs stabilized with 20% CCR cured at 40±2°C for 45 days produced with the clay material from Saaba improved tenfold (0.8 to 8.3 MPa) compared to Kamboinse (1.1 to 4.7 MPa), Pabre (2 to 7.1 MPa) and Kossodo (1.4 to 6.4 MPa). All clay materials are suitable for the production of stabilized CEBs with compressive strength of 4 MPa. Furthermore, the stabilization of the earthen material from Kamboinse using by product binders improved the structural efficiency of CEBs cured in ambient conditions of the lab (35±5°C): increase of compressive strength and decrease of bulk density. It also improved the hygro thermal efficiency: decrease of thermal effusivity, conductivity and diffusivity and increase of thermal specific capacity and water vapor sorption. The CEBs stabilized with at least 10 % CCR or 18-2 to 16:4 % CCR:RHA satisfy engineering requirements and durability for the construction of two or three storey buildings. Therefore, the selection of earthen materials should take into account the reactivity with the stabilizer. [less ▲]

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See detailBehavioral flexibility and ecological impact of opportunist northern pigtailed macaques (Macaca leonina) in a degraded environment of Thailand: Ranging pattern, foraging strategies and seed dispersal
Gazagne, Eva ULiege

Doctoral thesis (2020)

Southeast Asia experiences exceptionally high anthropogenic pressure, due to rapid human population growth. The resulting primary tropical forest loss and conversion to agricultural lands, plantations ... [more ▼]

Southeast Asia experiences exceptionally high anthropogenic pressure, due to rapid human population growth. The resulting primary tropical forest loss and conversion to agricultural lands, plantations, and infrastructures, are the driving forces leading to a massive tropical biodiversity crisis. The last remaining old-growth forests have been converted into archipelagos of forest fragments, rapidly becoming degraded. Animal and plant populations are directly threatened by degradation of forest structure, as well as distribution, quality and availability of forest resources, which ultimately modify overall ecosystem functionalities. One key feature is the extirpation of many large-bodied frugivores, the first affected by habitat degradation with a reduced fruit availability and an increased hunting pressure. Primates are particularly vulnerable to these threats, and nearly 84% of all Southeast Asian primate species are currently threatened with extinction. Only a few flexible and generalist species, such as macaques, are able to survive in human-modified landscapes. However, the way they respond to habitat degradation is not well understood yet, especially when it comes to skittish species. Since they are among the major seed-dispersal agents and play crucial roles in forest regeneration and maintenance, primates’ disappearance could result in detrimental long-term effect on tropical forest biodiversity. The omnivorous and opportunist northern pigtailed macaque (Macaca leonina) is an effective large-seed disperser, contributing to the tropical rainforest succession. However, very little is known about its ecology and behavioral response to habitat degradation. In order to understand how macaques adapt their movement ecology, ranging patterns, sleeping site selection, diet and foraging strategies under conditions of degradation, we studied the species in a degraded forest fragment within the old-growth Acacia and Eucalyptus plantations of the Sakaerat Biosphere Reserve (Sakaerat, hereafter), Northeastern Thailand. We concomitantly studied macaques’ generated seed shadow (i.e. the seed deposition pattern of a plant population) and their role as seed dispersers for potential forest regeneration. To do so, we followed a large wild-feeding troop of northern pigtailed macaques inhabiting Sakaerat for a 20-month period and collected eco-ethological data in regards to resource availability. We first habituated the troop of macaques to the observer’s presence and analyzed the habituation process over time. Based on the number of encounters, contact duration with the studied troop, and behavioral responses to the observer, we brought statistical evidences of the habituation progress over five stages: early, minimal, partial, advanced, and full. The complete habituation process took nearly thirteen months. Reduced native fruit availability in this degraded forest fragment, macaques’ limited experience of human contact, and their fission-fusion social dynamics, may explain the lengthiness of the process. Second, we investigated sleeping site selection patterns of northern pigtailed macaques over a period of 14 months by testing the hypotheses of random selection, predation avoidance, and food proximity. We identified a total of 107 sleeping sites with a low rate of reuse (N = 15 reused sleeping sites). Macaques sleeping sites were characterized by a low availability of large and tall trees and their selection pattern was not random: they slept more often in familiar areas, with a greater number of stems and a higher canopy height. These sleeping site characteristics were likely selected as an anti-predator strategy; however, food proximity also played a key role in sleeping site selection. Macaques often slept within or close to a feeding site, and selected their sleeping sites following food distribution. Third, we documented movement, ranging, and foraging patterns of northern pigtailed macaques based on 14 months of observation, and we used Hidden Markov Models (HMM) and Characteristic Hull Polygons to analyze these patterns in regard to fruit availability. Macaques’ home ranges encompassed a total of 599 ha and spanned through a natural dry-evergreen forest and a plantation forest. Our results showed that active foraging increased with higher native fruit availability, while macaques moved from foraging state to transiting to plantations and surrounding edge areas during periods of lower availability of native fruits. Accordingly, the macaques’ diet shifted from fleshy to dry fruits, such as the introduced Acacia species. Our results showed that the diet and movement ecology adaptations of northern pigtailed macaques in this degraded forest fragment were primarily dependent on availability of native fruit species, and that foraging strategies in the Sakaerat troop differed from northern pigtailed macaque populations inhabiting the nearby primary forest of Khao Yai National Park. Fourth, we illustrated a modeling approach of seed shadows, which incorporated field-collected data on the Sakaerat troop. We adapted a deterministic model of seed deposition with random components. We parameterized the model with macaque feeding behavior (i.e. consumed fruit species, seed treatments), gut and cheek pouch retention time, feeding and sleeping site location, daily activity, and movement patterns based on monthly fruit availability (analyzed with HMM). We found that northern pigtailed macaques dispersed many medium- to large-seeded species, across long distances in the degraded native forest and toward plantation forests (mean of dispersal distance > 500 m with a maximum range of 2300 m), and produced complementary seed shadows, with a sparse distribution of seeds spat out locally (mean > 50 m with a maximum range of 870 m). Our results showed that northern pigtailed macaques are effective seed dispersers in this degraded habitat. Overall, our findings provide novel insights regarding northern pigtailed macaques’ adaptability to habitat degradation, which include selection of numerous sleeping sites following food availability, use of exotic Acacia species in plantations to cope with native fruit scarcity, and use of large home range. These behavioral profiles result in long-distance dispersal events, giving an overview of their contributions to forest restoration and maintenance of ecosystem functions within their ranges. Our results bring a significant contribution to the current knowledge of the ecology and factors affecting ranging patterns, resource use, and seed dispersal effectiveness of the northern pigtailed macaque classified as vulnerable but still poorly-known, and constitute an essential starting point toward designing appropriate conservation strategies. [less ▲]

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See detailCregNET: Meta-Analysis of Chlamydomonas reinhardtii Gene Regulatory Network
Pham, Cam Ngoc ULiege

Doctoral thesis (2020)

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See detailVers un processus d’innovation managériale durable : une lecture par la traduction et les compromis
Fox, Fanny ULiege

Doctoral thesis (2020)

L’innovation managériale, au cœur des débats contemporains, demeure opaque à certains égards, notamment en raison des définitions attachées à dire ce qu’elle n’est pas. Ainsi, elle se distingue de ... [more ▼]

L’innovation managériale, au cœur des débats contemporains, demeure opaque à certains égards, notamment en raison des définitions attachées à dire ce qu’elle n’est pas. Ainsi, elle se distingue de l’innovation technologique, ne concerne pas le core business et s’éloigne des modes de gestion hiérarchique classiques. Notre recherche entend dépasser ces écueils pour se concentrer sur le processus d’innovation managériale et, partant, faciliter son déploiement. Trois articles explorent cinq études de cas, tantôt issues de recherches classiques, tantôt issues de recherches-interventions. Premièrement, la démarche de libération dans un organisme public est analysée à l’aune de la sociologie de la traduction. Ce projet, largement médiatisé, vise à réaménager les espaces et le temps de travail et à instiller une culture de responsabilisation. Les pierres d’achoppement, contradictions et acquis du changement sont mis en évidence, depuis sa conception jusqu’au suivi de sa mise en œuvre. Deuxièmement, les conséquences pour l’innovation managériale d’un revirement stratégique sont interrogées. D’une part, la responsabilisation et la transformation managériale au sein d’une industrie chocolatière sont délaissées. D’autre part, les ambitions d’innovation sociale pour une usine du futur sont abandonnées par une entreprise aéronautique. Plusieurs sources de vulnérabilité de l’innovation managériale, liées au processus de traduction et à l’asymétrie du rapport de forces, sont mises en lumière. Troisièmement, la mise en péril de l’innovation managériale par l’évolution du contexte est étudiée. D’un côté, une structure associative cherche à préserver son fonctionnement autogestionnaire. De l’autre, un fournisseur d’énergie souhaite maintenir sa culture atypique originelle. À l’aide de la théorie des conventions, l’examen du contenu des innovations managériales démontre la nécessaire construction d’un compromis dont le maintien devient un enjeu crucial. Ces résultats sont ensuite intégrés au sein d’une modélisation dynamique du processus d’innovation managériale susceptible d’en favoriser la durabilité. In fine, l’ensemble ouvre la voie à une réflexion sur la soutenabilité du processus d’innovation managériale et à des recommandations managériales. [less ▲]

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See detailWar in the darkness: biological alternatives to control wireworms
La Forgia, Diana ULiege

Doctoral thesis (2020)

Wireworms (Coleoptera : Elateridae) are common polyphagous soil-dwelling pest that feed on roots and tubers of many crops of high economical value. The use of pesticides is not always efficient because ... [more ▼]

Wireworms (Coleoptera : Elateridae) are common polyphagous soil-dwelling pest that feed on roots and tubers of many crops of high economical value. The use of pesticides is not always efficient because even a low density of wireworms can affect the field and be responsible for important economical damage. The withdrawal of many insecticide formulations (including neonicotinoids), leaves producers without control methods. They call for the development of efficient, cost-effective and environmentally-friendly solutions. In Chapter I, we list the existing alternatives to pesticides: they include natural enemies, biological agents and semiochemicals. We also discuss the potential of several associations of alternatives, such as the attractand-kill strategy that couple the use of microbial agents with semiochemicals. The aims pursued during the past four years of research were the development of such an attract-and-kill strategy of wireworm’s control. To do so, several sub-goals have been set : (a) developing behavioral assays on the wireworm orientation behavior (b) profiling volatile organic compounds (VOCs) released in the rhizosphere of maize (c) evaluating the role of the identified VOCs on wireworms foraging behavior (d) developing an attract-and-kill based on VOCs, associated with entomopathogenic nematodes (EPNs). In Chapter III, the main aim was the research of maize odors that could be attractive for wireworms. After field trials, we tested the hypothesis according to which different maize varieties have differential susceptibility/attraction to wireworms because they emit different VOCs from the roots. The work was focused on the VOCs quantification from the roots of two maize varieties having experienced contrasted levels of wireworm infestation in the field. We showed that the least susceptible variety released a more diverse blend of VOCs, including large amounts of hexanal, heptanal and 2,3-octenanedione. Behavioral assays showed that wireworms were strongly attracted to VOCs released by maize roots. However, when wireworms were offered both maize varieties, no preference was detected, contrasting with the field results. In Chapter IV, we investigated whether wireworms are able to use VOCs as cues to assess the suitability of maize plants that are already under attack by conspecifics. Seven compounds from plants and larvae have been identified, amongst which 2-Pentylfuran was present in high quantity, particularly in treatments where larvae were present. Behavioral assays in dual-choice olfactometer showed a significant attraction to 2- Pentylfuran. Finally, in Chapter V, we describe an attract-and-kill method using EPNs as biocontrol agent against wireworms. We first compared the efficiency of several EPN strains through classical screening laboratory assays (contact application of EPNs). Then, we developed an attract-and-kill system proposing alginate beads filled with EPNs and spiked with potato extract to larvae. The potato extract was previously tested as attractive for wireworms and easy to produce and to use in the laboratory tests. We found that the ingestion of these beads led to higher mortality rates. This method also demonstrated some signs of reduction of the wireworms metabolism. Through this work, we were able to deeper study the wireworms orientation behavior in terms of attraction to susceptible maize varieties. We showed that VOCs are part of the cues for the host plant detection. Still regarding the behavior, the larvae aggregation with conspecifics on plant roots was highlighted for the first time, opening an important research path. Finally, the development of the attract-and kill system combining VOCs with EPNs showed a long-term reduction of wireworms activity that needs to be tested in the field. The results obtained during these years of research will certainly open new paths in the study of the aggregation, the cues for the host selection and preference that could be combined to other biocontrol methods. In particular, the results open new perspectives on the development of a more efficient attract-andkill with the combination of more specific VOCs like 2-Pentylfuran and other EPNs strains. The pursuit of this research could lead to effective and innovative solution in wireworms control. [less ▲]

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See detailL’haptoglobine comme outil pronostique chez le bovin.
Severin, Marion ULiege

Master's dissertation (2020)

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See detailEffects of climate change on dairy farming systems: evaluation and impacts of heat stress on dairy cow in Tunisia
Amamou, Hajer ULiege

Doctoral thesis (2020)

The main objective of the research carried out within the framework of this thesis was to assess the risks related to climate change (CC), in particular heat stress (HS) in dairy cattle in Tunisia, and to ... [more ▼]

The main objective of the research carried out within the framework of this thesis was to assess the risks related to climate change (CC), in particular heat stress (HS) in dairy cattle in Tunisia, and to identify measures or indicators that could reveal the tolerance of dairy cows to HS. In the first study, an enquiry was conducted among 566 dairy farmers throughout Tunisia. The objective was to focus on Tunisian dairy farmers’ perceptions of the risks and the actions taken to cope with changes attributable to CC. A total of 70 diagnostic variables relating to farm characteristics, resources, management, performances and profit, in addition to CC risk perception and adaptation strategies, were used and analysed. A typology based on multivariate statistical analysis was carried out using variables related to the land, feed resources, labour and infrastructure. Four groups of dairy systems were identified. The largest proportions of farmers around 70% belonged to the landless dairy systems (Clusters 1 and 2), whereas the minority of farmers belonged to medium-sized (18%, Cluster 3) and large-sized (12%, Cluster 4) farm systems that specialized in milk production. The analyse of results showed that almost all the farmers in all the clusters perceived that the greatest impact of CC would be on cow performance and forage production. The study of the attitudes of the farmers towards adaptation to CC reveals that they sought, as a priority, to modify and adapt their current livestock housing infrastructure. Other identified strategies were related to the storage of forage reserves, the purchase of fodder and the promotion of irrigated areas. Although the CC-related concerns varied among the farming clusters, dairy farmers focus on short-term environmental modifications rather than longer-term actions to address CC effects. In the second study, the aspects of vulnerability to HS for dairy cattle farming systems in Tunisia was investigated for dressing adequate actions to combat CC effects. In order to do so, historical milk test-day records from official milk recording collected during 7 years were merged with historical temperature and humidity data provided by public weather stations. The results showed that dairy farms in Tunisia are exposed annually for 4 to 5 months with temperature-humidity index (THI) values above 72. Overall, the statistical models used in this study have shown that the tipping points (thresholds) of the THI at which milk yield started to decline ranged between 65 and 67. The largest milk decline per unit of THI above threshold values was 0.135±0.01 kg for multiparous cows. The milk losses estimated only during the 3 months of the summer period were 110 and 142 kg/cow in north and south, respectively. Individual cow response to heat load were estimated using random regression model and been considered as key measures of dairy farming system sensitivity assessment to HS. The results reveal the high sensitivity of Tunisian Holstein cows to HS especially in dairy farms characterized by large herd size and high level of milk production. In the third study, an on-farm experimental protocol was set up on 4 commercial dairy farms during summer (HS) and autumn (thermo-neutral) periods using direct physiological, on-barn temperature and relative humidity, milk yield and milk composition measurements. This study aimed to investigate the effects of HS on physiological and production parameters of dairy cows. When the THI went from an average value of 54 in autumn to 77 in summer, respiration rate (RR) and skin temperature (ST) increased by 2.3- and 1.3-fold higher, whereas milk yield per milking decreased by 24%. The results showed a linear relationship between THI and all physiological traits and an increases in RR (+2 breaths/min), ST (+0.5°C) and rectal temperature (RT) (+0.04°C) per increase in one THI unit. Inversely, milk, fat and protein yields showed a drop of 0.13 kg, 0.4 g and 0.3 g per milking per increase in one THI unit, respectively. Methodology of cluster analysis allowed to classify dairy cows into two clusters where 82% of cows belonged to Cluster 1 of heat-sensitive, whereas only 18% of cows belonged to Cluster 2 of heat-tolerant. The reaction norm models conducted to quantify the individual responses of cows across the trajectory of THI during the HS period revealed that heat-tolerant cows tended to have higher RR, ST, and RT and lower to almost no decrease in milk yield compared to heat-sensitive cows. The results also suggested that RR could be used as a reliable indicator for thermo-tolerance. In conclusion, this thesis shows that the CC-related concerns were linked to economic rather than climatic factors and adaptation strategies were focused on short-term environmental modifications to address CC effects in the Tunisian dairy farms. Moreover, dairy farms especially those characterized by large herd size and high level of milk production are highly sensitive to HS in Tunisia. At the individual scale, the RR might be used as an indicator for thermo-tolerance in order to assess HS and predict the thermal status in dairy cows. Only a small proportion (18%) of dairy cows were identified as heat-tolerant in our experiment. Overall, this thesis demonstrated that HS is a current problem in Tunisian dairy farms. Moreover, considering the CC, the severity and duration of HS will increase in the future, which would consequently lead to worsening economic losses. Our results highlight the need to implement immediate and proper management strategies to alleviate HS impacts, as well as future developments in animal breeding and dairy system sustainability to address the CC-related risks. [less ▲]

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See detailA damage to crack transition framework for ductile materials
Leclerc, Julien ULiege

Doctoral thesis (2020)

The simulation of the whole ductile fracture from the large-scale yielding to the localised crack initiation and propagation, is still challenging for scientists and engineers, especially under complex ... [more ▼]

The simulation of the whole ductile fracture from the large-scale yielding to the localised crack initiation and propagation, is still challenging for scientists and engineers, especially under complex loading conditions. In this work, we develop a computationally efficient and energetically consistent damage to crack transition framework to address this issue. In addition, we provide an appropriate porous material model as well as the related calibration procedure. Practically, an implicit non-local damage model represents the first diffuse damage stage, possibly beyond the softening onset. Once a crack insertion criterion is satisfied, a crack is introduced using a cohesive band model (CBM). This latter, contrarily to a cohesive zone model (CZM), accounts for 3D stress states during the crack opening which is mandatory in order to predict accurate results. The framework is implemented inside a Discontinuous Galerkin (DG) framework following the extrinsic CZM/DG formalism. Those choices ensure to the scheme interesting numerical properties demonstrated in this work: robustness upon failure, mesh-independence, energetic consistency and a reasonable trade-off between computational efficiency and simplicity. The framework is first applied to a damage-enhanced elastic behaviour where the cohesive band thickness, the only introduced numerical parameter by the CBM, is determined from energetic considerations. It is then extended to the context of large strains and porous plasticity. Therewith, a micromechanics model including void nucleation, growth and coalescence, is presented. A suited crack insertion criterion is derived from a micro-mechanics coalescence model. In both cases, the numerical model is validated using experimental results from the literature. Finally, the damage to crack transition model is validated with respect to an extensive experimental campaign studying a high-strength steel. The material and numerical models parameters are calibrated following micromechanics-based arguments. The framework, hence calibrated, is shown to be able to accurately predict the material behaviour until complete failure under different stress conditions and to include failure anisotropy. In particular, the complex experimental crack path on round bars and on grooved plates in plane strain is reproduced. [less ▲]

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See detailPrevention of African Swine Fever Virus: evasion mechanism, vaccine development and adjuvant for animal vaccine
Wu, Jing ULiege

Doctoral thesis (2020)

African swine fever (ASF) is a viral disease caused by African swine fever virus (ASFV), which leads high mortality in domestic pigs and wild boar. The occurrence of ASFV in affected countries often ... [more ▼]

African swine fever (ASF) is a viral disease caused by African swine fever virus (ASFV), which leads high mortality in domestic pigs and wild boar. The occurrence of ASFV in affected countries often provokes severe economic losses and ecological consequences. Lack of knowledge concerning the diversity of ASFV strains and the puzzling virus-host interactions involved in infection and immunity hinders the development of vaccines and complicates the control and eradication of ASF. Currently, there is no commercially available vaccine. In recent years, the prevalence of ASFV makes it urgent to acquire more knowledge and tools for protection against ASFV. In this thesis, we discussed the prevention of ASF from the following three aspects: immune evasion mechanism, vaccine development, and adjuvant for animal vaccine. Firstly, we demonstrated the action mechanism of DP96R gene of ASFV, which is one of the viral virulence factors. Results showed that DP96R of ASFV China2018/1 strain blocks the cytosolic cGAS-STING-TBK1 signaling pathway by inhibiting the activation of both TBK1 and IKKβ, thus down-regulating the expression of type I IFNs and inflammatory cytokines. This provides insightful information for further investigation to better understand the mechanism of immune evasion of ASFV. Secondly, we utilized dual expression vector to construct recombinant DNA plasmids encoding ASFV main structural genes, B646L (p72), E183L (p54), CP204L (p30), EP402R (CD2v) respectively, and genetic adjuvants (IRF3-5D, TBK1), then evaluated the induced immune responses following the administration of the DNA cocktail vaccines in mice. The results suggested ASFV DNA cocktail vaccines based on appropriate antigen genes and TBK1 as a genetic adjuvant offer a promising strategy for the development of ASFV vaccines. Thirdly, the action mechanism of new animal vaccine adjuvant pUC18-CpG was investigated. It stimulates RAW 264.7 mainly through the TBK1-mediated signaling pathway, causing the up-regulation of interferons and pro-inflammatory cytokines. It showed great adjuvanticity in mice and induced antigen-specific cytokine expression towards a Th1 based immune response. A better understanding of the pUC18-CpG is helpful for the promotion of its clinical application. In conclusion, we revealed a new immune evasion mechanism of ASFV, constructed a new type of ASFV DNA vaccine, and deepened our understanding of animal vaccine adjuvant (pUC18-CpG), which will provide theoretical knowledge and technical support for the prevention and control of ASF. [less ▲]

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See detailDevelopment of a modelling approach for characterization and prediction of bacterial spoilage microbiota dynamics in perishable foodstuffs
Cauchie, Emilie ULiege

Doctoral thesis (2020)

Food waste is currently a major problem since it is estimated that about one third of the food produced in the world is discarded before it is consumed. The reasons for these food losses and waste are ... [more ▼]

Food waste is currently a major problem since it is estimated that about one third of the food produced in the world is discarded before it is consumed. The reasons for these food losses and waste are varied and one cause is the bacterial spoilage, rendering foods unacceptable for consumption. The study of the dynamics of bacterial spoilage populations and the prediction of their dynamics would therefore be interesting to better understand and anticipate this phenomenon. This research focused on the study of predictive models for spoilage bacteria of fresh meat and meat products, considered as highly perishable foodstuffs. The two working matrices were pork minced meat and white pudding, considering variations in storage conditions (temperature and packaging). The first chapter of this thesis provides a general overview of bacterial spoilage of meat and meat products, as well as factors that may promote or limit its development. The different techniques used in this study to characterize and modelize the dynamics of spoilage microbiota are also described. This research was then divided into four main areas that are discussed in the other chapters: (1) describing the spoilage bacterial microbiota naturally present in the matrices studied; (2) characterizing the spoilage bacteria of interest for these products; (3) developing and validating predictive models with one or more bacteria; (4) and studying the metabolome of minced meat inoculated by spoilage microorganisms of interest. These studies have demonstrated the interest of combining results from classical microbiology and 16S rDNA-based metagenetic to monitor and predict the dynamics of spoilage microbiota. For the white pudding, the bacteria of interest were Brochothrix thermosphacta, Carnobacterium maltaromaticum, Lactobacillus spp. (Lb. fuchuensis, Lb. graminis, Lb. oligofermentans), Lactococcus lactis, Leuconostoc mesenteroides, Pseudomonas psychrophila, Pseudomonas sp., Psychrobacter spp. (Psy. okhotskensis, Psy. urativorans), Raoultella terrigena and Serratia sp. For minced pork samples they were B. thermosphacta, Lb. algidus, Lc. piscium, Leuconostoc spp. (Ln. inhae, Ln. gelidum), Photobacterium spp. (Ph. kishitanii, Ph. phosphoreum) and Pseudomonas spp. (Ps. fragi, Ps. fluorescens, Ps. psychrophila). The type of packaging and storage temperature have a significant effect on the different dynamics, as well as the food companies and the production batches analyzed. Some of these bacteria of interest were then inoculated on sterile and non-sterile matrices, stored at different temperatures and packaging. The growth parameters to each bacterium were collected: maximum growth rate, lag time, minimum and maximum bacterial populations, time to reach the stationary phase, time to reach the spoilage threshold, minimum growth temperature, etc. Packaging seems to have the greatest impact on the maximum growth rate, itself having the greatest influence on the microbiological shelf life of the foods studied. Based on these data, good adjustments were obtained for the growth simulations, but overestimations were often observed. The same observations could be made by comparing the simulations performed on the white pudding with those available from software (ComBase and Sym'Previus). For minced pork, the data obtained allowed the development of three species interaction models based on the Lotka-Volterra (prey-predator model) and the modified Jameson models. The simulations obtained were validated by monitoring the spoilage microbiota of naturally contaminated pork minced meat matrices. The modified Jameson model obtained the best adjustments, although the prey-predator approach seems to be an interesting interaction model for complex microbiota. However, these proposals for models with three or more spoilage bacteria need to be validated by more experimental repetitions. Finally, metabolomic analyses (1H-NMR), in collaboration with CIRM-CHU, were performed in order to monitor the metabolites produced by inoculated bacteria in sterile minced pork samples. The dynamics of the metabolome for sterile non-inoculated matrices was also monitored. The different metabolomic patterns and metabolites produced were highlighted according to the inoculated bacteria and the food packaging. Moreover, the storage temperature seems to have the lowest impact on the metabolome. Development of predictive models based on data obtained by multi-omics analyses, combined with classical microbiology, provide an interesting approach. Further research on the development of complex models integrating the dynamics of two or more spoilage bacteria, interacting with each other and with the natural microbiota of foodstuffs, will be also an important step for better understanding and anticipating the bacterial spoilage of perishable foodstuffs. [less ▲]

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See detailValorisation de molécules biosourcées en flux continu
Tshibalonza Ntumba, Nelly ULiege

Doctoral thesis (2020)

Dans le contexte actuel d’une conscientisation forte du grand public quant à l’empreinte globale associée à la production des produits du quotidien, le développement de procédés industriels alternatifs ... [more ▼]

Dans le contexte actuel d’une conscientisation forte du grand public quant à l’empreinte globale associée à la production des produits du quotidien, le développement de procédés industriels alternatifs aux procédés pétrosourcés devient une réalité de plus en plus marquée. La bioraffinerie vise à la transformation de matières premières naturelles et renouvelables (non fossiles) afin d’alimenter alternativement les filières chimiques traditionnellement exclusivement pétrosourcées. L’utilisation de ressources renouvelables pour alimenter les différentes filières chimiques est motivée à la fois par une volonté de réduire l’impact environnemental et de palier à la diminution des réserves de ressources fossiles. Dans ce travail, des matières premières biosourcées, comme le glycérol, l'érythritol, l'acide shikimique et l'acide quinique ont été transformés en produits à haute valeur ajoutée d’utilité particulière pour l'industrie chimique. Ces transformations ont été réalisées en flux continu dans des microréacteurs spécifiquement construits pour ces applications. Nous avons développé une application unique de la réaction de désoxydéshydratation (DODH) pour la préparation d’oléfines, produits typiquement pétrosourcés, à partir de composés biosourcés. L’application de la réaction de DODH en conditions microfluidiques a permis d’obtenir des très bons rendements en alcool allylique (84%) à partir du glycérol commercial. De même que le glycérol non purifié, issu de la synthèse du biodiesel que nous avons réalisée à partir de l'huile de Jatropha curcas a donné 86% d’alcool allylique. Un profil varié des produits (3-butène-1,2-diol, 1,3-butadiène, 2,5-dihydrofurane et crotonaldéhyde) dont les proportions sont liées aux conditions de réaction a été obtenu à partir de l'érythritol, avec des rendements modérés à quantitatifs. Le 3-butène-1,2-diol obtenu (56%), non purifié, a été transformé lors d'une synthèse subséquente, en vinyléthylène carbonate (71%), un produit à haute valeur ajoutée pour l’industrie des polymères. L'acide shikimique et l'acide quinique ont été transformés en acide benzoïque (60% et 6% respectivement). Les mécanismes et sélectivités sont également étudiés afin de pouvoir orienter les réactions. Ce travail fournit un outil efficace et original pour la transformation des molécules issues de la biomasse, facile à mettre en œuvre, avec les avantages d'opérer à des temps de réaction brefs, et avec une sécurité inhérente à haute température. [less ▲]

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See detailAgro-industrial feed ingredients, a novel approach to enhance intestinal health in weaned piglets: from in vitro to in vivo perspectives
Uerlings, Julie ULiege

Doctoral thesis (2020)

Weaning is a critical transition period in pig production with major dietary, behavioural and environmental challenges leading to tremendous physiological, immunological and microbiological changes in the ... [more ▼]

Weaning is a critical transition period in pig production with major dietary, behavioural and environmental challenges leading to tremendous physiological, immunological and microbiological changes in the piglet’s intestines. This multifactorial process predisposes the piglets to subsequent intestinal disturbances and infections, resulting in poor performance and diarrhoea. To tackle the current problematic expansion of antibiotic resistance, nutritional management is yet another promising strategy to alleviate intestinal disorders around weaning. By-products from the agro-industrial sector and, to a lesser extent, whole cereals and roots, are major sources of dietary fibres suitable for livestock feeding. These native sources of ingredients could represent potential prebiotic candidates due to the heterogeneous dietary fibre components embedded in their cell wall matrix. These feed ingredients, regarded as environmental-friendly, socially accepted and more economic and sustainable than antimicrobials and isolated fibre fractions, are therefore of upmost interest. However, among potential dietary strategies, mainly purified fibre fractions have been accepted and promoted, while the prebiotic capacities of several cereals, roots and corresponding by-products remain to be investigated. We therefore hypothesised that the prebiotic effects of these feed ingredients could reach or overcome the ones of isolated fibre fractions. For this purpose, 36 fibre-rich feed ingredients were first tested in a three-step in vitro model of the piglet’s gastro-intestinal tract for their prebiotic potential (objective 1), measuring the gas kinetics, short-chain fatty acid and microbiota profiles in the fermentation broth as indicators of prebiotic activity. Several feed ingredients such as chicory pulp, citrus and orange by-products, rye bran and soybean hulls, with complex structural composition varying in soluble and insoluble dietary fibres and distinct constituent sugars, positively modulated health-related microbiota communities in the fermentation broths, reaching or overcoming the prebiotic effect of their corresponding purified fraction and/or inulin. Purified fractions were ranked as highly fermentable, with inulin displaying the most interesting prebiotic profile as butyrogenic ingredient. Subsequently, the six most promising ingredients were tested via a functional in vitro fermentation – cell culture assay (objective 2) combining the in vitro batch fermentation model with cultured intestinal porcine epithelial cells (IPEC-J2), for their barrier-enhancing and immunomodulatory effects. Inulin and its fermentation metabolites promoted the intestinal barrier function via up-regulated expressions of tight and adherens junction genes. Chicory pulp fermentation supernatant enhanced the intestinal barrier integrity and seemed to induce anti-inflammatory and pro-apoptotic regulations in comparison to inulin, while the fermentation supernatants of chicory root, citrus pulp, rye bran and soybean hulls only showed minor immunomodulatory effects. These in vitro assays led to preliminary conclusions that allowed the selection of the most promising ingredients for the third objective of the thesis, i.e. evaluating the inclusion of citrus pulp (0.2 % and 2 %) and inulin (0.2 %) in the feed of newly weaned piglets in vivo. The aim was to provide insights into their capacities to modulate intestinal fermentation, ecology, morphology, inflammation and permeability, with the purpose of improving gut health at weaning, and hence, reducing the incidence of infections. We observed that citrus pulp improved gut morphology and promoted colonic fermentation at weaning without depressing growth performance or impairing the inflammatory response and the intestinal barrier function. Colonic health-associated microbiota communities were notably enhanced in both the early and late post-weaning stages under citrus pulp supplementation at 2 %. A decline in colonic branched-chain fatty acids, concomitant with greater acetate proportions, was also observed and could account for a possible reduction of proteolytic fermentation in newly weaned piglets following citrus pulp inclusion at 2 %. Moreover, greater villus height to crypt depth ratios were observed following citrus pulp (0.2 % and 2 %) and inulin supplementations, which might suggest the capacity of the ingredients to cope with epithelial damage during the weaning transition. Citrus pulp could therefore be considered as a valuable nutritional strategy for future inclusion in the weaner diet. In summary, this thesis improved our understanding of dietary fibre management around weaning using whole cereals, roots and by-products from the agro-industrial sector. The heterogeneous sources of endogenous dietary carbohydrates present in these feed ingredients, causing a more gradual degradation, could effectively maintain fermentation throughout the entire hindgut. Several types of feed ingredients may therefore be promising alternatives to antimicrobials and pure fibre fractions, to reduce the prevalence of post-weaning diarrhoea. Nevertheless, a challenge trial could better recreate the conditions encountered in commercial production at weaning and might provide a clearer picture of the preventive or curative effects of these feed ingredients against pathogen infection at weaning. Alternatively, using the functional fermentation – cell culture model, other feed ingredients and their fermentation metabolites may be tested for their bioactive properties for future inclusion in young mammalian diets. [less ▲]

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See detailStudy on the processing technology of iced roasted sweet potato and its sensory characteristics and nutritional peculiarities
Hou, Feina ULiege

Doctoral thesis (2020)

Nowadays, fresh sweet potato is greatly influenced by seasonality and unable to be consumed all year. The roast sweet potato in market is usually made by personal, so the quality, safety and nutrition ... [more ▼]

Nowadays, fresh sweet potato is greatly influenced by seasonality and unable to be consumed all year. The roast sweet potato in market is usually made by personal, so the quality, safety and nutrition cannot be guaranteed effectively. In addition, roasted sweet potato is hard to storage and has a short shelf-life, what’s more, the price of roast sweet potato is high due to its seasonality, thus reducing consumers’ desire to buy it. Therefore, a new iced roasted sweet potato product which has a long shelf-life, good taste, and high nutritional value should be developed to meet the needs of consumers. Firstly, we studied on changes in nutritional and functional value of roasted sweet potato during roasting and selected the special cultivar of roasted sweet potato. There were significant differences in the proximate and nutritional composition of the fresh and roasted sweet potatoes from the different cultivars. The results showed that fresh and roasted sweet potatoes were both rich in protein and dietary fiber, with low gross energy and fat. After roasting, the starch and protein contents declined, while total phenolic content and antioxidant activity were increased, and most of vitamins are preserved. In addition, the comprehensive nutritional value of Yanshu No.25 ranked first. Secondly, we optimized the processing technology of roasted sweet potatoes. The results showed that roasting time, roasting temperature and roasting speed affected the measured responses, and the optimal roasting conditions included a roasting time of 40 min, a roasting temperature of 235°C, and a roasting speed of 40 rad/min. Under the optimal conditions, the result of reducing sugar content is 47.79±0.43 g/100g DW, the result of vitamin C content is 60.25±0.67 mg/100 g DW. In addition, 38 volatile compounds were identified in roasted sweet potato by GC-MS, 2-methyl butanal was the main aromatic compound. Low-field NMR results showed that roasting changes the water distribution, the proportion of free water increased and relaxation times (T2) were decreased after roasting process. Thirdly, the effects of different freezing temperature on structure, moisture distribution, sensory, and nutritional characteristics of iced roasted sweet potato was studied. The results of ice crystals formation and microstructure showed that the tissues were severely damaged at freezing temperature of -18 °C, which took the longest freezing time (5.09 h). What’s more, the samples of -18 °C showed softer texture (hardness 454.39 g) and darker color (L* value 86.50) than that of the -40 °C and -70 °C frozen samples. The analysis of NMR and drip loss demonstrated that the condition of -18 °C freezing maintained less the intracellular water content. Moreover, with the freezing temperature increased, vitamin C and TPC content was decreased significantly, while protein and dietary fiber content did not show significant change. In conclusion, quality of the roasted sweet potato is better under the quick-frozen condition. According to this dissertation, these investigations about raw sweet potato and roasted sweet potato qualities lead to a better understanding of the influence of processing technology on roasted sweet potato and propose new insight in improving the quality of sweet potato products. In spite of the extensive available information about the effect of roasting in different sweet potato cultivars, much of the work is essentially descriptive. What’s more, Maillard and other reactions during roasting process of sweet potatoes are complicated, and the formation of characteristic flavor is more complex, which requires further research. More basic research is still needed to elucidate the underlying mechanisms of reaction during roasting and freezing. [less ▲]

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See detailÉTUDE DE LA CONNECTIVITÉ HYDROLOGIQUE ET SÉDIMENTAIRE EN MILIEU DE PLATEAU LIMONEUX AGRICOLE – MESURE, MODÉLISATION ET AMÉNAGEMENT D’UN BASSIN-VERSANT
Cantreul, Vincent ULiege

Doctoral thesis (2020)

Le ruissellement et l’érosion qui en découle impliquent de nombreuses conséquences en milieu agricole en Europe de l’ouest. Les coulées boueuses survenant après certains événements pluvieux induisent des ... [more ▼]

Le ruissellement et l’érosion qui en découle impliquent de nombreuses conséquences en milieu agricole en Europe de l’ouest. Les coulées boueuses survenant après certains événements pluvieux induisent des dégâts sur la parcelle (perte en sol, perte d’éléments chimiques, dégâts aux cultures, etc.) et hors de celle-ci lors de la sédimentation (dégâts aux infrastructures, aux habitations, pollution chimique, etc.). Les causes des schémas spatiaux de redistribution des sédiments sont nombreuses et varient dans le temps et dans l’espace. Depuis quelques années, la notion de connectivité permet de mieux décrire les mouvements d’eau et de sédiments sur le bassin-versant. Son étude en contexte de plateau limoneux pouvant être approfondie, la connectivité demande à être décrite via des mesures et des modélisations pour comprendre les schémas spatiaux de redistribution. Le site étudié est un bassin-versant limoneux (356 ha) en contexte agricole belge. Les techniques de mesure (ex : acquisition du modèle numérique de terrain par drone) et de modélisation demandent le choix d’une taille de pixel adéquate. L’impact de ce choix a été testé en utilisant un indice de connectivité (IC de Borselli). Entre 25 cm et 10 m, des différences de 20 % au niveau de l’IC sont observables et finalement 1 m apparait comme étant la taille de pixel adéquate pour étudier la connectivité en région agricole, au vu des comparaisons réalisées sur le terrain. Il a de plus été démontré qu’au-delà de cette taille, les schémas spatiaux de connectivité (ex : éléments linéaires du paysage) sont affectés. En deçà, le temps de calcul est décuplé et les informations supplémentaires sur la connectivité sont marginales. La prédiction du ruissellement et de l’érosion consécutifs à un événement pluvieux demande l’utilisation de modèles. LandSoil, un modèle à base experte, permet de quantifier l’érosion sans multiplier le nombre de paramètres. La validation du modèle avec des mesures de terrain spatialisées est nécessaire. Des canaux de mesures de hauteur, des débitmètres et des réglettes graduées ont mis en évidence une bonne quantification du modèle sur des zones >10 ha. L’analyse des résultats a pointé une grande influence de l’occupation du sol, de l’allocation des cultures, du design du bassin-versant ainsi que des pentes. Au niveau des éléments linéaires du paysage, les bandes enherbées déposent des sédiments pour des pentes <2 %. Les bandes boisées diminuent fortement la connectivité mais déposent des quantités moindres de sédiments. Les limites de parcelles jouent quant à elles un rôle prépondérant sur le transport des sédiments mais pas sur leur quantité. La démonstration faite des performances de LandSoil pour la quantification du ruissellement et de l’érosion en région agricole belge permet de réaliser des scénarios d’aménagements. Ultime étape avant la mise en œuvre, l’utilisation de modèles est un outil de communication avec les pouvoirs compétents. La comparaison de 9 scénarios d’aménagements pour limiter l’érosion a été réalisée, tous venant d’experts. Ils comprennent bande enherbée, bande de bois, fascine, haie ainsi que travail sur le sens et l’intensité du labour. L’efficacité des scénarios au niveau export de ruissellement et de sédiments est comprise entre 1 et 17 % pour le ruissellement et entre 4 et 53 % pour l’érosion pour la période de retour de 100 ans (entre 1 et 34 % pour le ruissellement et entre 1 et 85 % pour l’érosion pour la période de retour de 2 ans).La période de retour testée a un effet important sur la réduction du ruissellement et de l’érosion. Les haies permettent de diminuer significativement le ruissellement alors que les bandes enherbées et les bois déposent plus de sédiments. Les fascines ont un rôle antiérosif pour de faibles aires contributives ou pour de grandes densités d’installation dans le paysage. Les volumes de dépôt dépendent du degré de déconnexion de l’aménagement ainsi que de l’aire déconnectée en amont de celui-ci. Un point important pour tous les dispositifs est le positionnement près des sources d’érosion linéaire, dans le chemin d’écoulement concentré ou directement en amont de zones à risque. Pour des objectifs de recherche en adéquation avec les qualités et inconvénients de LandSoil, pour des bassins-versant de petite taille (quelques centaines d’hectares maximum) et en mesurant les inputs minutieusement, ce modèle devient un outil puissant de quantification du ruissellement et de l’érosion en zone agricole. [less ▲]

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See detailContribution à l’étude de la réponse immune contre les dermatophytes à l’aide d’un modèle murin d’infection à Trichophyton benhamiae.
Heinen, Marie-Pierre ULiege

Doctoral thesis (2020)

Dermatophytoses are widespread superficial skin mycosis known to affect more than 20% of the human population, making them the most common fungal infections. Pathogenic dermatophytes are specialized ... [more ▼]

Dermatophytoses are widespread superficial skin mycosis known to affect more than 20% of the human population, making them the most common fungal infections. Pathogenic dermatophytes are specialized filamentous fungi that exhibit the capacity to invade keratinized tissues and produce infections that are generally restricted to the stratum corneum, hair, and nails. Despite their superficial localization, these fungi induce an immune response that remains poorly documented as compared to that observed with other fungal infections. Although the ability of dermatophytes to induce innate response is documented, little is known about the adaptive immune responses against these fungi. Furthermore, the inoculation route in most in vivo models used for studying the immune response against dermatophytes fails to mimic the natural epicutaneous infection or even induce observable skin lesions. Some clinical case studies, however, have shown that resolution of dermatophytoses is associated with the development of cell-mediated immunity with T helper (Th) type 1 polarization. At the beginning of this work, despite the crucial role of Th17 response in many other fungal diseases, particularly at mucosal surfaces, no study had yet experimentally documented Th17 response in dermatophytoses. In this regard, a relevant mouse model of dermatophytosis had just been developed at the Laboratory. In the first part of this work, by comparing Trichophyton benhamiae acute superficial dermatophytosis in WT and Rag2−/− mice, we evidenced that TCR-mediated immunity is critical for the optimal control of acute dermatophytosis and that adaptive immunity is polarized to both Th1 and Th17 responses. Using IL-17A-deficient, IFN-γ-deficient and IL-17A and IFN-γ double-deficient mice we next evidenced that theses two pathways function in a complementary manner, with the Th17 antifungal response acting on dermatophyte clearance and the Th1 one being involved in both fungal clearance and Th17-inflammation down-modulation. In mammals, it is generally accepted that, besides an increased epidermal turnover, the two main effector and regulatory mechanisms in the fight against opportunistic fungal skin infections are the cytotoxic and phagocytic activity of polymorphonuclear neutrophil (PMN)s, as well as the production of antimicrobial peptides (AMP)s at the site of infection. PMNs and AMP have long been known as key elements of the cutaneous innate immune system, but interest in these has drastically increased with the discovery of the Th17 pathway, particularly in fungal infections. Indeed, in skin and mucosal defence against fungi, IL-17 and IL-22, the major’s cytokines of Th17 family, have essential role for promoting PMN mobilization and regulating AMP production at the site of infection. Both attraction of PMNs and production of AMPs occur upon infection with dermatophytes and have been associated with host protection in human and experimental infections but the implication of the different immune components in the triggering of these two defences mechanisms had so far never been studied in acute superficial dermatophytosis. In the second part of this work, we evidenced for the first time that while in situ PMN attraction and AMP production can occur without the intervention of TCR-mediated immunity, this last significantly contributes to optimally strengthen these two defense mechanisms in acute superficial dermatophytosis. We next demonstrated that innate and Th17-secreted IL-17A significantly contributed to increase the in situ PMN attraction and that the actions of PMNs significantly contribute to decrease the fungal loads. We also evidenced that, while single IL-17A and IFN-γ deficiencies had no impact on the AMP production in our model of superficial T. benhamiae infection, a double IFN-γ and IL-17A deficiency significantly decreased it. These two lasts observations suggest not only a preponderant role of a Th17-secreted non-IL-17 cytokine, probably IL-22, in the AMPs production but also possible synergistic actions of this unknow cytokine with IL-17A and also with IFN-γ on the AMPs production, particulary in the case of IFN-γ and IL-17A deficiencies respectively. In parallel with these experiments, we infected the various aforementioned strains of mice after having depleted them in PMN, and we evidenced that the action of the PMNs contributed significantly to reduce the fungal loads but that other mechanisms, such as the local AMP production, certainly helped to reduce the fungal skin load and prevent the dissemination of the dermatophyte beyond the skin, especially in the case of deficiencies affecting the cutaneous PMNs infiltration. Taken together these data suggest that, during acute superficial dermatophytosis, Th17 immune response contributes to the fungal clearance by strengthening the innate in situ PMN infiltration and AMP production, with preponderant roles of IL-17A on the PMN recruitement and of an other Th17-secreted cytokine, probably IL-22, on AMP production, alone or in synergy with IL-17A or IFN-γ. [less ▲]

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See detailEvolution paléoenvironnementale du delta de la Medjerda et géoarchéologie du site d'Utique (Tunisie)
Pleuger, Elisa ULiege

Doctoral thesis (2020)

Utica is considered, according to ancient literary tradition, as one of the first three Phoenician foundations of the Western Mediterranean, supposedly founded in 1101 BC by Levantines from Tyre ... [more ▼]

Utica is considered, according to ancient literary tradition, as one of the first three Phoenician foundations of the Western Mediterranean, supposedly founded in 1101 BC by Levantines from Tyre. Nevertheless, until now, no archaeological remains date back beyond the 9th century BC. In the Phoenician and Roman periods, Utica was an important merchant coastal town, facing the sea. Over the centuries, the city has lost its access to the sea and its port has silted up. Despite more than a century of investigation by archaeologists and associated researchers, the location of the city’s harbour, dating from the Phoenician and Roman periods, remains unknown, buried under several meters of sediment. Starting from this archaeological problem, our research focused on three main axes: paleogeographic, geoarchaeological and palynological. Based on the multidisciplinary study of sedimentary cores, the results showed that the strong floods of the Medjerda wadi, which flowed south of the city during Roman times, were a major factor in the decline of Utica and the silting of its port. Indeed, at the time of its foundation, the city was located on a promontory bathed by the sea, but the sediments transported by the Medjerda gradually sealed the bay, leaving the tip of the Utica promontory 10 km inland. A major hydrological crisis was highlighted around the 4th century AD. This is correlated with an increase in sedimentation rates in the watershed, which seems to correspond to an overall climatic degradation. The results also highlight the existence of a long maritime façade north of the Utica promontory during the Phoenician and Roman eras. A deep marine environment is attested in the ancient bay at 6th mill. BC and the depth of the water column along the north facade was still 2 m around the 4th–3rd centuries BC. Finally, the palynological study showed the existence of traces of human activities as early as the 3rd mill. BC. The Phoenician and Roman occupation is characterized by a sharp drop in forest taxa, probably due to significant clearings for agriculture and pastoralism. The olive tree is increasing, as well as cereals. The erosive crisis occurring at the end of the Roman period was accompanied by a sharp increase of Artemisia, witnessing a steppisation of the landscape. This work illustrates the contribution of geoarchaeology to the resolution of a major archaeological problem and to the understanding of the relationships between this important port city and its environment. [less ▲]

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See detailINVESTIGATION SUR LA QUALITE DU LAIT CRU PRODUIT DANS LE BASSIN LAITIER DE NIAMEY (NIGER)
Morou Madougou, Amadou ULiege

Doctoral thesis (2020)

Livestock breeding is an important activity in agriculture in Niger. This sector is facing huge problems, such as the weak productivity of the animals, the weak investment, the feeding and watering ... [more ▼]

Livestock breeding is an important activity in agriculture in Niger. This sector is facing huge problems, such as the weak productivity of the animals, the weak investment, the feeding and watering difficulty and the recurrent sanitary problems. Niger is a landlocked country with an area of 1,267,000 km², whose southernmost border is more than 600 km from the sea (Gulf of Guinea) and according to National Institute of statistics (INS), Niger has a population of 19,124,884. In Niger, which is a predominantly agro-pastoral country, breeding is performed by nearly 87% of the active population either as a main activity or as a secondary activity after agriculture. Breeding is a determining factor in the context of food security and poverty reduction. On average, it contributes to household income at a level of 15% and to food security at a level of 25%. In Niger, the animal species supplying milk are: cattle, goats, camelids and sheep. The main cattle breeds involved in milk production come from several local breeds from Bos taurus (Kouri) and Bos indicus (Azawak, Bororo, Djelli, Goudali). There are mainly three major national dairy sectors, namely peri-urban, rural and ranching..The average milk production is 2.4 l/ cow / day in the rainy season compared to 2 l in the dry and cold season and 1.4 l in the dry and hot season. Analysis of the evolution of dietary pattern shows a tendency towards increased consumption of dairy products in West Africa, particularly in urban areas, where populations with no dairy consumption pattern have rapidly adopted them. The development of the dairy sector requires a real consideration of the control of health risks to ensure the health of the consumer, the quality and hygiene of the products. Poor hygiene control is the main source of contamination since several foodborne pathogens can be transmitted by raw milk. There are few data on the microbiological quality of raw milk in Niger. Therefore, the raw milk microbiota from three collection centres (Kollo, Hamdallaye and Say) and three farms (Toukounous, Kirkissoye and Niamey) in Niger have been evaluated using two methods, the classical microbiology and metagenetic. The objective of this study was to assess the microbiological quality of raw milk produced in Niger and compare it with similar production methods in other countries. To perform this, we enumerated microorganisms that indicates the hygiene quality and safety of raw milk (coliforms, Escherichia coli and Staphylococcus aureus) and then we performed metagenetics analyzes in order to obtain a global image of the microbiota. The use of metagenetic analysis aimed to get an insight of indigenous bacterial compositions and to enhance the safety and quality of raw milk with high-throughput sequencing technology through 16S rDNA metagenetics (also called metagenomics analysis targeting 16S ribosomal DNA). We wanted also to assess the presence of antibiotics residues, the levels of hygiene indicator bacteria and the occurrence of coagulase positive Staphylococcus. Data collected in this study may be useful for an exposure assessment of Niger inhabitants to foodborne pathogens present in raw milk. Samples were submitted to classical microbiology for Aerobic Total Microbiological Counts (ATMC) at 30°C, the enumeration of coagulase positive Staphylococcus and E. coli (ECC) and total coliforms counts (TCC), while metagenetic analysis was performed on the same samples. V1–V3 hypervariable 16S rDNA amplicon libraries were prepared for each sample and sequenced with MiSeq Illumina sequence (V3 kit). Taxonomical assignment and clustering were performed with Mothur using SILVA database. Metagenetic analysis of sequencing data for the V1-V3 region of 16S rDNA resulted in the identification of dominant populations and in the evaluation of their relative abundance. In descending order of abundance, the following phyla were recovered: Proteobacteria, Firmicutes and Actinobacteria. The main species encountered were Acinetobacter, Staphylococcus, Klebsiella, Escherichia spp, Lactobacillus spp, Lactococcus spp and a part of the whole population was composed of isolates issued from environmental origin, as Enhydrobacter spp and Kocuria spp. Taxonomical assignment and clustering were performed with Mothur using SILVA database. Screening of antibiotic residues was performed using a standardized biological test kit form, the Delvotest®. In total, of the 192 samples of raw milk, 19 (10.1%) were positive. s. A voluntary survey of raw milk consumers was performed to learn about foodborne disease. Following the answers of interviewed consumers, a rate of 25% foodborne illness among people who consume raw milk directly out of 194 survey respondents was detected. The results show that hygiene rules are not respected in the production of raw milk and that raw milk is directly consumed without any heat treatment before consumption. This presents a serious public health risk. In conclusion, the quality of raw milk can be improved by using the good hygiene practice during milking, collection and transport of raw milk and only the heat treatment of the milk can help to limit health risks for consumers. [less ▲]

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See detailContribution à la mise en évidence des facteurs influençant le succès de l’introduction du robot de traite au pâturage
Lessire, Françoise ULiege

Doctoral thesis (2020)

Le développement de la traite robotisée a représenté un changement majeur dans le secteur laitier que ce soit au niveau du quotidien des éleveurs, pour les vétérinaires et conseillers en élevage ou ... [more ▼]

Le développement de la traite robotisée a représenté un changement majeur dans le secteur laitier que ce soit au niveau du quotidien des éleveurs, pour les vétérinaires et conseillers en élevage ou l’industrie laitière. Ce changement touche un nombre croissant d’exploitations au point qu’en Belgique, 2017, une nouvelle installation de traite sur 2 était robotisée (Fedagrim, 2019). Dès les années 2000, s’est posée la question de la possibilité de poursuivre le pâturage dans les exploitations robotisées. La réponse à cette interrogation est difficile car liée à différents contextes, par exemple l’obligation de pâturer pour des questions de bien-être animal pendant une certaine période de l’année en Suède, alors que dans certains pays d’élevage plus extensif comme la Nouvelle Zélande ou l’Irlande, le pâturage est incontournable. Les publications relatives à ces questions sont donc conjoncturelles. La première publication intégrée dans cette thèse a recensé les différents systèmes développés dans 7 pays qui ont participé au projet Européen AUTOGRASSMILK. Rapidement, il a été établi que le robot de traite associé au pâturage générait moins de traites. En effet, 2,7 traites automatisées par vache et par jour peuvent être enregistrées en moyenne à l’étable, alors qu’en système pâturant, la fréquence de traite atteint difficilement plus de 2 traites par jour. La gestion de la circulation des animaux vers le robot est généralement plus difficile au pâturage, expliquant la diminution de cet indicateur de performances. Alors qu’à l’étable, le retour vers le robot met en jeu un comportement individuel, en prairie, l’instinct grégaire des animaux se marque davantage, avec pour conséquence une répartition des traites moins homogène sur la journée. D’autres facteurs entrent également en jeu : les vaches sont soumises à d’autres contraintes, telles que la distance au robot, la disponibilité en eau, les aléas climatiques…Les facteurs influençant la circulation des animaux au pâturage peuvent être classés en paramétrables (que l’exploitant peut modifier) et non paramétrables (sur lesquels l’exploitant n’a pas de contrôle). La partie expérimentale de ce travail est divisé en trois parties. Le premier volet concerne les facteurs paramétrables permettant la combinaison du robot et du pâturage, le deuxième volet étudie les facteurs climatiques, non paramétrables et le dernier fait la synthèse des précédentes parties. Le premier article fait l’état des lieux des différentes stratégies mises en place en Europe pour aménager un robot de traite en prairie. La deuxième publication a eu pour objectif de vérifier si les modalités d’attribution de concentré avaient un impact sur la fréquentation du robot par les vaches au pâturage. En effet, à l’étable, il est reconnu que la circulation des animaux est améliorée par la distribution de quantités variables de concentrés. Vérifier l’impact de cette distribution dans un système de robot au pâturage a donc paru judicieux. La gestion des grands troupeaux semble facilitée par les systèmes robotisés. En effet, l’automatisation de la traite permet de suppléer à la demande en main d’œuvre nécessaire pour la gestion d’un troupeau de telles tailles. De plus, la génération de rapports et les différentes alarmes disponibles permettraient de faciliter la surveillance des animaux avec des interventions humaines limitées. Les troisième et quatrième études ont visé à évaluer la possibilité de pratiquer le pâturage dans deux troupeaux de plus de 100 animaux et de vérifier l’intérêt économique de cet aménagement. Les animaux en prairie sont davantage soumis aux aléas climatiques susceptibles de modifier leur comportement. Or, dans le contexte du réchauffement climatique, les épisodes de stress thermiques deviennent plus fréquents. L’objectif de la cinquième étude a été de quantifier les impacts de conditions météorologiques contrastées sur les déplacements, la production laitière et le temps de rumination des vaches laitières en système 100% pâturant. [less ▲]

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See detailTrophic ecology of Southern Ocean sea stars: Influence of environmental drivers on trophic diversity
Le Bourg, Baptiste ULiege

Doctoral thesis (2020)

Like in the rest of the world, climate change impacts the Southern Ocean, but not in the same way in all regions of this ocean. Changes in sea ice cover around the Antarctic continent are one of the most ... [more ▼]

Like in the rest of the world, climate change impacts the Southern Ocean, but not in the same way in all regions of this ocean. Changes in sea ice cover around the Antarctic continent are one of the most visible manifestations. For example, sea ice cover has decreased significantly in the Western Antarctic Peninsula while it tends to increase slightly on the rest of the coastline of the continent. These changes in environmental conditions influence the functioning of the ecosystems of this ocean. In particular, the disappearance or persistence of sea ice in a region where it was seasonally present may prevent the appearance of summer phytoplankton blooms, thus impacting the dynamics of krill populations and their predators in the pelagic environment. The benthic environment will also be disturbed by environmental modifications resulting from climate change, as organic matter fluxes toward this compartment will be affected. Sea stars (Echinodermata: Asteroidea) are a key component of Southern Ocean benthos, with 12% of the known sea star species living there. In temperate environments, this taxon may play an important role in the functioning of ecosystems with its trophic interactions controlling the populations of other organisms, which themselves have a large effect on the ecosystems. This group is considered to be quite resistant to changes of seawater temperature in the Antarctic environment. However, it will likely be affected by changes of environmental conditions and functioning of food webs. Indeed, a reduction in the abundance or disappearance of common prey can lead to an increased competition in sea star assemblages. In order to determine the ecological role of sea stars in the Southern Ocean and to understand how they might be impacted by climate change, a study of their trophic ecology and of the factors controlling it is necessary. Therefore, the objectives of this PhD thesis were to determine the trophic role of sea stars in the Southern Ocean, and how environmental factors such as turbidity, depth and sea ice impact their trophic diversity. To do so, stable isotope values of carbon (δ13C), nitrogen (δ15N) and sulfur (δ34S) were analysed in tissues of sea star sampled across the Southern Ocean (n = 2454 individuals, plus data on 204 individuals from the literature or shared by colleagues). A significant proportion of the sea star samples came from collections archived in institutions and/or museums, which significantly increased the spatial and temporal coverage of the study. However, most of these samples were preserved in ethanol, and some have been previously fixed with formaldehyde. Preservative fluids may alter the stable isotope values of biological tissues. Therefore, the impact of the preservation method on the stable isotope values in sea star tissues was studied (chapter 3). A two year-long experiment showed that it was possible to mathematically correct the effect of preservative fluids on stable isotope values in sea stars, making it possible to use archived samples for trophic ecology studies. In order to better understand the potential importance of sea stars in the ecosystems of the Southern Ocean, the food web of subantarctic Macrocystis pyrifera (Phaeophyceae, Laminariales; or “kelp”) forests was reconstructed by analysing stable isotope values in invertebrate (19 taxa, including 6 sea star taxa) and primary producer tissues sampled in the Kerguelen Islands (chapter 4). Mixing models did not highlight major Macrocystis pyrifera consumers and showed that the food web is supported by pelagic organic matter and live (with the exception of kelp) or detrital micro/macrophytobenthos. This suggests that sea stars do not have the same ecological function in Macrocystis pyrifera forests from subantarctic regions than in those from more temperate regions, where they control grazer populations. The results also show that sea stars are not only top predators in the food chain. On the one hand, some species may occupy lower trophic positions. On the other hand, their trophic niches may not overlap: some species rely more on the food chain supported by pelagic production and others on the food chain supported by benthic (including detrital) production. Following this analysis of an entire food web, isotopic niches of sea stars were compared at a local scale, and the possible relationship between ontogenetic changes, i.e. changes during growth, and trophic ecology were studied (chapter 5). The analysis of stable isotope values in sea stars sampled in Ezcurra Inlet (Admiralty Bay, King George Island, South Shetland Islands, chapter 5) showed that the size, and especially the central disc radius, can be linked to stable isotope values in some species, indicating the occurrence of ontogenetic changes in the diet of these species. This was observed only in some species, and notably omnivore species, for which the trophic position increased with body size. The relationship between the disc radius and the trophic ecology may be explained by larger sea stars being able to evert their stomach over larger areas and thus consume larger prey and/or prey with higher trophic level. For sediment feeding and potentially suspension feeding species, the relationship between size and stable isotope values was usually not observed, suggesting lower variability of the trophic ecology between size classes in these species. The analysis of stable isotope values in sea stars sampled in Ezcurra Inlet also indicates that the diet variability of some sea star species may be important, which in part determines their interspecific trophic interactions. The turbidity generated by the terrestrial inputs provided by meltwater run-off from terrestrial glaciers results in an important environmental gradient from the inner to the outer Ezcurra Inlet, which determines the habitat conditions and the characteristics of the resources available for sea stars. Some species may adapt their diet depending on those variable conditions. Interspecific interactions are also impacted. Indeed, the Diplasterias brandti and Odontaster validus species have more different δ13C values (i.e. more different food sources) and lower isotopic niche overlap in the inner inlet, where high turbidity occurs, than in the outer, where turbidity is lower. Similarly, the size of the isotopic niche of Odontaster validus is smaller in the inner Ezcurra Inlet than in the outer. This is probably the result of a more limited availability and diversity of resources in the inner inlet. This may lead to the constriction of Odontaster validus isotopic niche and to resource segregation that may limit interspecific competition between the few species able to survive in these unfavourable conditions. In the chapter 6, the impact of trophic group, depth, sea ice concentration and sea ice season duration on the trophic ecology of sea stars was assessed thanks to a global analysis of the dataset at the scale of the whole Southern Ocean. The Southern Ocean was subdivided into different benthic ecoregions according to environmental (seabed temperature, sea ice, bathymetry) and biotic data (species distribution), to study biogeographic variations in the trophic ecology of sea stars. This subdivision notably highlighted the separation between Antarctic and Subantarctic environments, with the different δ13C values in organic matter from the surface in Subantarctic and Antarctic waters being reflected in tissues from benthic sea stars. In this chapter, the compilation of the available information on their diet allowed to make a classification of sea star taxa from the Southern Ocean into trophic groups, ranging from suspension feeders to predators of active prey. The differences of stable isotope values between trophic groups and their variability in some of them suggested a diversity of food sources and/or of feeding strategies between and within trophic groups. These results confirm that, contrary to what is sometimes stated in the literature, sea stars in the Southern Ocean show a great trophic diversity. Depth has important effects on the trophic ecology of sea stars, both across the entire Southern Ocean and within ecoregions. Indeed, coastal sea stars may exploit food webs supported by a variety of pelagic and benthic primary producers while deeper sea stars may depend on the sedimentation of the surface primary production. Coastal sea stars are then characterised by a high diversity of food sources, while deeper sea stars have a higher diversity of trophic positions than coastal ones. The lower diversity and availability of food sources in deep waters may induce the diversification of sea star feeding behaviours (e.g. omnivory, predation, sediment feeding), which would reduce competition between species. The impact of sea ice on the trophic ecology of sea stars was also investigated. The sympagic communities may be used as a food source by sea stars in case high sea ice concentrations. Furthermore, increasing reliance on degraded phytodetritus during longer periods of sea ice cover may occur in several trophic groups. This may dampen the impacts of sea ice presence on resource availability during long periods of sea ice cover. Our results also suggest that multiple relationships do exist between sea ice and the diet of benthic consumers, but they are not easy to interpret. Finally, not all of them are consistent across ecoregions, probably as a result of their contrasted oceanographic features. In addition, the impacts of the environmental parameters may differ between trophic groups, highlighting the importance of trophic diversity to predict the sensitivity of sea stars to future environmental changes, whether natural or anthropogenic. To summarise, the studies of this thesis show that the trophic ecology of sea stars from the Southern Ocean is impacted by a combination of intrinsic (body size, trophic group) and extrinsic features (turbidity, depth, sea ice). Information on the influence of environmental parameters may provide hypotheses regarding the possible impacts of climate change on sea stars and on their role in benthic food webs of the Southern Ocean. Indeed, the environmental parameters may influence the trophic ecology of sea stars and the trophic interactions between taxa thanks to their impact on resource availability. The lower diversity and availability of food sources in turbid and deep waters have been considered as potential sources of diversification of feeding behaviours to avoid competition between species. By contrast, their greater availability in less turbid and coastal environments allows the consumption of similar prey with limited risks of competition. Sea ice has more variable impacts on resource availability, being an habitat for sympagic communities and inducing phytoplankton blooms after its break up, but inhibiting them in case of persistence. Consequently, changes in the ice cover and its dynamics because of climate change will induce changes in the resource availability for the Southern Ocean benthos. Similarly, changes in turbidity in coastal areas as a result of modifications in the dynamics of terrestrial glaciers could have consequences on resource availability in this type of environment. These changes are likely to modify the trophic interactions between sea star taxa, with an increase or decrease of the importance of competition, which may result in modifications of the structure of sea star assemblages in the Southern Ocean. [less ▲]

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See detailStudy on flavor composition and factors influencing the formation of volatile compounds in stewed pork
Han, Dong ULiege

Doctoral thesis (2020)

The traditional stewed pork is a famous sauce pickled product in China and often produced by stewing the fresh pork in aged brine. Here, the aged brine included water and various ingredients such as salt ... [more ▼]

The traditional stewed pork is a famous sauce pickled product in China and often produced by stewing the fresh pork in aged brine. Here, the aged brine included water and various ingredients such as salt, sugar, spices, soy sauce and cooking wine. Because of its unique sensory characteristics, for example tender texture, bright colour and rich flavour, the stewed pork is appreciated by consumers. However, the traditional stewed pork also has faced a number of potential problems in recent years. Among them, the most important is the volatilization and loss of flavour compounds. In order to solve this problem, the flavour compounds in the stewed pork were fully analysed and a new processing technology were proposed. Firstly, the flavour compounds profile and odour-active compounds in the stewed pork from four local brands, Dahongmen (DHM), Daoxiangcun (DXC), Henghuitong (HHT) and Tianfuhao (TFH), were evaluated by GC-MS/O and E-nose combined with chemometrics analysis. A total of 62 volatile compounds were identified and quantified in all pork samples, and 24 of them were considered as odour-active compounds because their OAVs were greater than 1. According to principal components analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) of GC-MS/O and E-nose data, the stewed pork samples were divided into three groups (DHM, HHT, and DXC-TFH). The PLS-DA result showed that 9 odour-active compounds (heptanal, nonanal, 3-carene, D-limonene, β-phellandrene, p-cymene, eugenol, 2-ethylfuran and 2-pentylfuran) were confirmed to the potential flavour markers for the discrimination of stewed pork products. Secondly, the effects of different pork breeds on the aroma profiles of boiled pork were investigated. The three varieties of pigs are Tibetan, Sanmenxia and Duroc × (Landrace × Yorkshire). The volatile compounds and odour-active compounds in boiled pork from three different breeds of pigs were identified and quantified using gas chromatography-olfactometry-mass spectrometry (GC-MS/O) and odour activity values (OAVs). A total of 61 volatile compounds were identified, among which 25 compounds were selected as odour-active compounds in boiled pork. Hexanal, nonanal, 1-octen-3-ol, dimethyl disulphide, heptanal, 2-pentylfuran and 2-ethylfuran were the important contributors to the whole flavour of boiled pork. The flavour profile was determined by E-nose based on principal component analysis (PCA). This result showed that boiled pork from the three pig breeds could be clearly distinguished. The radar chart of response value of E-noes sensors displayed the boiled pork from different pig breeds had significantly different flavour, and that boiled pork from the fore leg and hind leg muscles of pigs had similar aroma compositions. The above analyses showed the different pig breeds had a greater influence on flavour of boiled pork than pigs in different parts, and the GC-MS/O combined with E-nose was a feasible method to determine and distinguish the volatile profiles of different varieties of pork samples. Besides, the influence of different seasoning recipes (SP1: stewing pork in water, SP2: stewing pork with water and salt, SP3: stewing pork with water, salt and spices, SP4: stewing pork with water, salt, spices and soy sauce, SP5: stewing pork with water, salt, spices, soy sauce and sugar, SP6: stewing pork with water, salt, spices, soy sauce, sugar and cooking wine) on volatile profiles and sensory evaluation of stewed pork were studied. The GC-MS/O and two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC × GC-TOFMS) were applied to detect the flavour profile in stewed pork form different seasoning recipes. The stewed pork processed using SP1 and SP2 had the most abundant volatile compounds, especially aldehydes. Which indicated that the cooked pork with water and salt promoted lipid oxidation and amino acid degradation. Samples SP3, SP4, SP5 and SP6 were close each other in PC1-PC2, whereas samples SP3 was located on the opposite side of samples SP4, SP5 and SP6 in PC1-PC3 using PCA. It was showed that the addition of spices had a significant influence on the flavour of stewed pork. Sensory evaluation revealed the stronger spicy odour, caramel odour and soy sauce odour were presented in samples SP3, SP4, SP5 and SP6. These results were consistent with the results of partial least squares regression (PLSR). Finally, the volatile compounds and non-volatile compounds of stewed pork with different processing methods (TS: traditional stewing, TSE: traditional stewing with enzymatic degradation, TSE: traditional stewing with enzymatic degradation and Maillard reaction, HS: high-temperature stewing, HSE: high-temperature stewing with enzymatic degradation, HSEM: high-temperature stewing with enzymatic degradation and Maillard reaction) were analysed. The high-temperature stewed pork (HS, HSE and HSEM) had a higher content of volatile composition than traditional stewed pork (TS, TSE and TSEM), especially sample HSEM. The traditional and high-temperature stewed pork samples clearly distinguished by E-nose method. The contents of umami amino acids (UAAs), sweet amino acids (SAAs) and bitter amino acids (BAAs) of high-temperature stewed pork were higher significantly (P < 0.05) than those of traditional stewed pork, of which the content of Asp and Glu related to umami taste were the most in sample HS and HSEM. The high-temperature stewed pork showed the lower contents of 5’-nucleotides and fatty acids (FAs) than traditional stewed pork. It was concluded that the pork with high-temperature stewing (HS, HSE and HSEM) could be used as an effective method to improve the taste and odour of stewed pork, moreover, sample HSEM had a great advantage in the formation of odour compounds. [less ▲]

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See detailN2O exchanges by three agricultural plots in Southern Belgium: Dynamics and response to meteorological drivers and agricultural practices.
Lognoul, Margaux ULiege

Doctoral thesis (2020)

In Belgium, managed soils are responsible for more than 60 % of N2O emissions from agriculture. This thesis aimed at gaining insight on the influence of farming practices and meteorological conditions on ... [more ▼]

In Belgium, managed soils are responsible for more than 60 % of N2O emissions from agriculture. This thesis aimed at gaining insight on the influence of farming practices and meteorological conditions on N2O emissions and flux dynamics in crops and grassland in Belgium. We worked on three research focus points: (1) the suitability of eddy covariance to measure N2O fluxes, (2) the influence of farming practices on N2O exchanges and (3) the weight of N2O in the greenhouse gas budget of managed soils. Three measurement campaigns were setup in Southern Belgium. In 2015, two sets of automated dynamic closed chambers were used to monitor N2O exchanges in a maize crop with the aim of studying the long-term effect of contrasting tillage practices (conventional tillage vs. reduced tillage) in experimental plots. In 2016, at the Lonzée ICOS Station, N2O emissions were measured by eddy covariance in a sugar beet crop from fertilization to harvest. Finally, in 2018, at the Dorinne ICOS Station, we set up a paired-flux tower measurement campaign to assess the impact of pasture restoration vs. business-as-usual on a control parcel. After 8 years of contrasting tillage practices, N2O and CO2 emissions were respectively 10 times and twice larger in the parcel under reduced tillage than in the conventionally tilled parcel. Reduced tillage practices, by limiting the mixing of crop residues to the topsoil layer, favor microbial development and increase N and C availability for microorganisms. In the sugar beet crop, we observed a large N2O emission peak following fertilization. While this event was expected, a surprising result was the inhibition of this burst after the seed-bed preparation, which constituted a first-time observation. We hypothesized that the microbiome was disturbed by this shallow soil disturbance. This hypothesis would benefit from further investigations. We estimated that N2O emissions accounted for at least 20 % of the net greenhouse gas budget of the crop, highlighting the importance of including N2O when assessing budgets from fertilized soils. Finally, the paired-flux tower experiment in a pasture revealed that, during the first year, restoration practices can trigger high N2O emissions, although not as great as fertilizer and cattle excreta-induced N2O peaks in non-restored parcels, and with different flux dynamics. All in all, these results confirmed that N2O emissions by managed lands are influenced by farming practices, particularly those implying soil disturbance, on the long and short-term. More research is needed to fully understand how N2O production mechanisms are affected by tillage and soil preparation practices. [less ▲]

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See detailDevelopment of novel aptasensors for the detection of mycotoxins
Guo, Xiaodong ULiege

Doctoral thesis (2020)

Mycotoxins contaminants, one of the most serious global challenges, have been attracted more and more attention from International Agency for Research on Cancer (IARC) of the World Health Organization ... [more ▼]

Mycotoxins contaminants, one of the most serious global challenges, have been attracted more and more attention from International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) and scientists in food safety sciences. Many countries and organizations have established the maximum contamination level of the main mycotoxins at very low values. Traditional analytic strategies are mainly based on instrumental quantitative method and immunoassays approaches. Aptamer, a novel molecules recognition element like or even superior to antibodies, has attracted more and more attentions for scientists. Therefore, specific aptamers could be employed to construct biosensors for the detection of mycotoxins. The objective of this thesis is to develop novel aptamer-based biosensors for sensitive determination of trace levels of mycotoxins and to provide a promising application of these aptasensors for more hazard factors in food safety sciences. The main contents and results are as follows: (1) Aptamer-based biosensor for detection of mycotoxins Mycotoxins are a large types of secondary metabolites appeared by fungi, they pose a great hazard and toxic reactions to human and animals. A majority of countries and regulators, such as European Union, have established series of requirements and set the maximum tolerated levels. The development of high sensitive and specific analytical platform for mycotoxins is much in demand to address new challenges for food safety in worldwide. Due to the superiority of simple, rapid, and low-cost characteristics, aptamer-based biosensors are successfully developed for the detection of various mycotoxins with high sensitivity and selectivity compared with traditional instrumental methods and immunological approaches. In this article, we discuss and analyze the development of aptasensors for mycotoxins determination in food and agricultural products during the last eleven years and cover the literatures from the first report in 2008 until today. In addition, challenges and future trends for the selection of aptamers towards various mycotoxins and aptasensors for multi-mycotoxins analysis are summarized. Given the promising development and potential application of aptasensors, the future researches will witness the great practicability of aptamer-based biosensor for food safety field. (2) A qPCR aptasensor for sensitive detection of aflatoxin M1 Aflatoxin M1 (AFM1), one of the most toxic mycotoxins, imposes serious health hazards. AFM1 had previously been classified as a group 2B carcinogen (IARC, 1993) and has been classified as a group 1 carcinogen by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) (IARC, 2002). Determination of AFM1 thus plays an important role for quality control of food safety. In this work, a sensitive and reliable aptasensor was developed for the detection of AFM1. The immobilization of aptamer through a strong interaction with biotin–streptavidin was used as a molecular recognition element, and its complementary ssDNA was employed as the template for a real-time quantitative polymerase chain reaction (RT-qPCR) amplification. Under optimized assay conditions, a linear relationship (ranging from 1.0×10-4 to 1.0 µg L-1) was achieved with a limit of detection (LOD) down to 0.03 ng L-1. In addition, the aptasensor developed here exhibits high selectivity for AFM1 over other mycotoxins and small effects from cross-reaction with structural analogs. The method proposed here has been successfully applied to quantitative determination of AFM1 in infant rice cereal and infant milk powder samples. Results demonstrated that the current approach is potentially useful for food safety analysis, and it could be extended to a large number of targets. (3) A novel graphene oxide-based aptasensor for amplified fluorescent detection of aflatoxin M1 in milk powder In this paper, a rapid and sensitive fluorescent aptasensor for the detection of aflatoxin M1 (AFM1) in milk powder has been developed. Graphene oxide (GO) was employed to quench the fluorescence of carboxyfluorescein-labelled aptamer and protect the aptamer from nuclease cleavage. Upon the addition of AFM1, a formation of AFM1/aptamer complex resulted in the aptamer detached from the surface of GO, then the aptamer was cleaved by DNase I and the target AFM1 was released for a new cycle, which led to a great signal amplification and high sensitivity. Under optimized conditions, the GO-based detection of the aptasensor exhibited a linear response to AFM1 in a dynamic range from 0.2 to 10 μg/kg, with a limit of detection (LOD) of 0.05 μg/kg. Moreover, the developed aptasensor showed a high specificity towards AFM1 without interference from other mycotoxins. In addition, the technique has been successfully applied for detection of AFM1 in infant milk powder samples. This aptasensor proposed here offers a promising technology for food safety and can be extended to various targets. (4) Graphene oxide driven fluorescent aptasensor for the detection of fumonisin B1 Fumonisin B1 (FB1), one of the most toxic mycotoxins, has been designated as possible 2B group carcinogen by the International Agency for Research on Cancer (IARC) in 2002. Therefore, simple, sensitive and specific approaches for the detection of FB1 are much in demand. In this study, a novel aptasensor was introduced for FB1 analysis based on graphene oxide (GO) and DNase I signal amplification. GO was adopted as a fluorescence quencher against ROX-modified aptamer and a protectant for the aptamer from cleavaging by DNase I for subsequent target cycling and signal amplification detection. This proposed sensing strategy exhibited a good linearity for FB1 determination in the dynamic range from 0.5 to 20 ng mL-1 with a good correlation of R2 = 0.995. Its detection of limit was established at 0.15 ng mL-1 (S/N = 3). The specific analysis indicated that this aptasensor was selective for FB1 other than other mycotoxins. In addition, the practical application in real samples of this aptasensor for the detection of FB1 was investigated. The sensing platform proposed here was useful for a potential application in the field of food safety for mycotoxins analysis. (5) Articles highlights and future perspective By using the novel aptamer-based biosensors, we developed several approaches for the detection of the most toxic mycotoxins for food safety. In addition, these sensing strategies could be applied for more hazard factors determination by simple replacement of the specific aptamers. More importantly, though the practical applicability, feasibility, and accuracy of these proposed aptasensors were investigated and evaluated through the analysis of the spiked samples experiments, the future’s researches were needed for a validation of these aptasensors with real contaminated samples to determine the performances such as limit of detection and quantification, precision, trueness, accuracy, etc. Through the method validation, these aptasensors will be widely used for the detection of mycotoxins. In addition, future direction will focus on the simplification of analytic principle and devices and the combination of novel aptamers with new materials and techniques to improve the analytical performance and market practicality of aptasensors. [less ▲]

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See detailHow to value labor in agricultural production: a case study in the Red River Delta, Vietnam
Nguyen Thi Hai Ninh, ULiege

Doctoral thesis (2020)

In Vietnam rural area, agricultural production is still a main occupational activity of millions laborers and be major income source of them. Despite this important role, it is often debated that the most ... [more ▼]

In Vietnam rural area, agricultural production is still a main occupational activity of millions laborers and be major income source of them. Despite this important role, it is often debated that the most concerning issue in labor market of Vietnam rural areas is job creation. In other word, the actual capacity of agriculture to create new employment is rather low compare to non-agricultural sectors. This issue leads to the large migration of young, experienced and skilled laborers from rural to urban areas as well as from agriculture to non-agricultural sectors. As a consequence, agricultural labor in many provinces of the country are mostly un-trained and the old aged. This shortage of skilled laborers not only directly affects agricultural production at farm household level but also is a challenge to the implementation of rural renewal targets of the Vietnamese Government. Furthermore, the lack of new job creation for agricultural works in parallel with poor skilled and old aged result in the low wage rate of laborers who work in agricultural sector. This wage rate is equivalent to two-third of the wage of employees in industrial sector, and 50% of the wage of those working in service sector. Not only wage, other forms of value of agricultural employees such as social protection, working condition are also less concerned by employers in rural labor market and the current Vietnam Labor Code neither. In order cope with the shortage of skilled farm labor, rural households in the Red River delta diversify their use of labor by combining family laborers with hired laborers for agricultural activities. Family labor source contains both family farm laborers and family non-farm laborers but still participating in farming activities of the household, especially in the peak season. Within 220 households of the three provinces investigated in this thesis, the highest proportion of family farm laborers is over 45 years old and women are discovered to mostly in charge in agricultural production, especially in rice farming. That is because more non-farm jobs opportunities open for young, healthy, and skilled men rather than women. Hired laborers in agriculture in Bac Ninh, Hai Duong and Thai Binh provinces are divided into two types, seasonal hired laborers and permanent hired laborers. Seasonal laborers are often hired to work in peaking time. In rice farming households, seasonal hired laborers usually work for short period of time such as for the land preparing, transplanting, and harvesting. In clam farming households, seasonal laborers are widely rent in preparing clam plots and harvesting. In general, women are observed to work in seasonal hiring more frequently than men in both household groups. However, seasonal hired laborers are not detected in pig farming group. Alternatively, laborers in this group are hired on a permanent or longer-term basis, normally from three months to a year. When using hired laborers in agricultural production, farm households give the laborers payment that are equivalent to their labor value. Of these payment, wage is considered as the most important value of hired laborers. Basically, the wage is paid in two methods, daily wage for seasonal laborers and monthly wage for permanent ones. The daily wage is applied for farming activities which last within a few days such as manual transplanting, manual harvesting in rice farming or clam harvesting. The daily wage may be paid in piece for activities such as land preparation and spraying pesticide. Whereas, the monthly wage is common for laborers in pig farming and clam plot guarding. The wage is counted for 30 working days. Average monthly wage of a hired laborer is 161 USD in pig farming and 175 USD in clam farming. Thus, wage rate of hired farm labor in the study sites is equivalent to 70% and 66% of the wage of laborers in industrial and service sector, respectively. A part from the wage, there are different forms of labor values paid by the householders through remuneration such as drink, lunch, bonus for good performance and support for sickness. Such remuneration can be paid in cash or in kind which ranges from 0.3 to 9 USD. For hired laborers, labor welfare usually is a luxury metric as they work in farm households with only verbal agreement. Without written contract, they receive no health insurance and social insurance support. Despite the rather low in wage and labor welfare, hired laborers still present the satisfaction with their employment. Wage is a work feature which contributes the most to their satisfaction, relation with householder is the second important factor. This relationship proves a crucial function of social relation in driving labor supply and demand in agricultural labor market rather than an economic one. Similar to many developing countries, imperfect information is a typical characteristic of the agricultural labor market of the Red River delta, Vietnam. This imperfection influences labor demand in terms of raising cost for monitoring hired laborers of farm households. On the other side, labor migration is considered as a determinant impacting on labor supply of the rural labor market. This study discovers a positive correlation between remittance of migrated laborers sending home and wage paid to hired laborers in the pig and clam farming groups. Conversely, the more development of agricultural machinery renting market, the less value that householders have to pay for hiring manual farm laborers. In addition to these external determinants, farm size of household, gender and work experience are internal factors which impact on the wage rate that hired laborers can receive. Among the three household groups, the wage of hired laborers in the clam farming is 3.9% higher than the one in the rice farming group. In order to increase the labor value in agricultural production, several interventions by central government and local authorities at different levels in the Red River delta should be taken into account: (1) including agricultural wage laborers into the governance of labor code; (2) promoting the operation of employment service centers in rural areas; (3) improving work skill of farm laborers above 40 years old through training courses which connect with labor demand in the rural labor market. [less ▲]

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See detailDrawing from the Archives: Comics Memory in the Contemporary Graphic Novel, post 2000
Crucifix, Benoît ULiege

Doctoral thesis (2020)

At a turning point of its institutionalization and in a fast-changing media environment, the graphic novel prompted a fascination with the history of comics and a rediscovery of semi-forgotten works: by ... [more ▼]

At a turning point of its institutionalization and in a fast-changing media environment, the graphic novel prompted a fascination with the history of comics and a rediscovery of semi-forgotten works: by 2004, the graphic novel was a well-established phenomenon, and its stabilization opened up a moment when moving forward meant looking backward, caught by Art Spiegelman’s oft-quoted aphorism “the future of comics is in the past.” This interplay of innovation and tradition, rupture and continuity, is a puzzling phenomenon in the graphic novel, and yet one that has remained comparatively unaddressed. For all their differences and idiosyncrasies, cartoonists as Chris Ware and Art Spiegelman—but also Seth, Charles Burns, Daniel Clowes, and others—share a common visual heritage and an interest in passing it on to new readers and next generations. This dissertation is an inquiry into the gestures of transmission that embed the contemporary graphic novel within a longer history and a collective memory. It is organized around a set of practices that, taken together, all illustrate ways of ‘drawing from the archives’ in its twofold meaning: as a process of selecting from material repositories and as an appropriation of its objects that entails a more or less significant kind of graphic intervention or manipulation. Whether it is within the framework of an exhibition or of on an online platform, drawing, or redrawing, or more generally using and displacing drawn images are here orchestrated as performative gestures of transmission. In focusing on such gestures, this dissertation embraces both settings in which traditional gatekeepers have a strong hold (the museum, the library, the book market) and where comics might (un)willingly integrate or replicate the canonizing mechanisms of an official culture; and makes room for more attention to smaller vernacular gestures that establish and sustain a relationship with the past in the margins of (or in collaboration with) more traditional mechanisms of preservation. [less ▲]

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See detailBiodiversity and ecosystem services in tropical forests: the role of forest allocations in the Dja area, Cameroon
Lhoest, Simon ULiege

Doctoral thesis (2020)

Due to human-driven environmental changes, planet Earth has entered the new Anthropocene era, with major impact on biological diversity recognized as the sixth mass extinction period. The concepts of ... [more ▼]

Due to human-driven environmental changes, planet Earth has entered the new Anthropocene era, with major impact on biological diversity recognized as the sixth mass extinction period. The concepts of biodiversity and ecosystem services (ES) have risen to objectify and measure the human impacts on ecosystems and the many-fold contributions of ecosystems to human well-being. Among global terrestrial ecosystems, tropical forests are particularly important for the conservation of biodiversity and for the provision of ES. Agricultural conversion, logging, hunting, commercial poaching and over-harvesting lead to deforestation, degradation and defaunation of tropical forests, with highly variable consequences depending on many local factors. In Central Africa in particular, biodiversity and ES have been far less studied than in other tropical regions, despite the vital roles of these tropical forests in the livelihood of tens of millions of people in a context of high poverty. A better understanding of the determinants of biodiversity and ES in Central Africa is crucial for improving human well-being and the resilience of forest ecosystems. Despite the still relatively preserved tree cover across the region, biodiversity and ES may differ depending on forest land management and allocations. Therefore, the objective of this thesis is to assess the conservation value of tropical forests in southeastern Cameroon, as well as the supply of ES and use by local populations, in three contrasted forest allocations: a protected area, a Forest Stewardship Council (FSC)-certified logging concession, and three community forests. First, we assessed the conservation value of the three forest allocations, examining species richness and composition of two taxonomic groups: mammals inventoried with 44 camera traps, and dung beetles inventoried with 72 pitfall traps (Chapter 2). We also aimed to identify the determinants of forest conservation value, disentangling the effects of forest allocations, proximity to human settlements (villages and roads), and local forest habitat. Mammal and dung beetle species showed lower species richness in the community forests than in the protected area, and intermediate values in the logging concession. Proximity to human settlements and disturbance was negatively correlated to species richness of both groups, negatively correlated with species body size, and associated to the loss of the most threatened mammal species. The high species variability among forest allocations (i.e., spatial turnover) suggests that any conservation initiative should integrate many sites to protect a multitude of species, and not only large isolated areas. The high conservation value of the protected area has been confirmed, and the logging concession can play a complementary role in conservation strategies through landscape connectivity. In contrast, community forests are particularly defaunated due to their proximity to roads and villages, but they still provide wild proteins to local populations. Second, we assessed the perceptions of the supply of ES by tropical forests to local populations, and the determinants of these perceptions (Chapter 3). We evaluated the significance and abundance of ES by conducting a questionnaire survey with 225 forest stakeholders. The most significant ES perceptions were provisioning services (93% of respondents) and cultural services (68%), while regulating services were much less reported (16%). The perceptions of ES abundance were relatively homogeneous among forest allocations and respondents. Bushmeat provision has been identified as the only significant ES for local populations that is not supplied in high abundance. Third, we depicted the use of ES by local populations in three villages, and we evaluated its determinants and sustainability (Chapter 4). We used diverse interviews and field surveys to assess three provisioning services (bushmeat, firewood, and timber) and five cultural services (cultural heritage, inspiration, spiritual experience, recreation, and education). On average, local populations consumed 56 kg of bushmeat person–1 year–1 (hunting zones covering on average 213 km² per village), 1.17 m³ of firewood person–1 year–1 (collection zones on average 4 km² per village), and 0.03 m³ of timber person–1 year–1. On average, 59% of respondents recognized the importance of cultural services. The main determinants of ES use were forest allocations, population size, and deforestation rate, and we also showed slight differences between Baka and Bantu people in the use of cultural services. Firewood and timber have been shown to be used sustainably by local populations in this area, whereas bushmeat hunting and consumption have exceeded sustainability thresholds. Finally, the main findings of the thesis are summarized and their practical implications are discussed, in particular for the role of forest allocations (Chapter 5). The potential reconciliation between conservation and the sustainable use of tropical forests is discussed. Methodological feedbacks are given for the use of mammals and dung beetles as biodiversity indicators. Research perspectives are presented for a better understanding of the interactions between biodiversity and ES. Finally, different perspectives for integrating the concept of ES in tropical forest management are given: for instance, identifying and resolving conflicts among stakeholders, raising awareness, making decisions, or evaluating the effectiveness of conservation measures. In particular, ES are increasingly used in concrete management applications, such as FSC-certification, payments for environmental services, UNESCO Man and Biosphere Reserves, and various development projects. [less ▲]

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See detailÉvaluation sur le retentissement psycho-affectif du patient de l'utilisation de l'imagerie médicale combinant les images du scanner et la dosimétrie en tant qu'outil d'éducation thérapeutique en radiothérapie médicale : une étude de faisabilité
Kirkove, Delphine ULiege

Master's dissertation (2020)

Problem studied: Lung cancer is major public health problem because of its high frequency and high mortality. Its usual treatment consists in taking advantage of radiotherapy, combined or not with ... [more ▼]

Problem studied: Lung cancer is major public health problem because of its high frequency and high mortality. Its usual treatment consists in taking advantage of radiotherapy, combined or not with chemotherapy, with significant medical side-effects and psycho-affective impact, which harms the quality of life. Even though information is already given to patients, the use of the personal medical images as a tool for therapeutic education has not been studied yet. Population: Adult patients with lung cancer or with lung metastasis, benefiting from external radiotherapy treatment in the radiotherapy department of the CHU of Liège. Method: Experimental study of type “randomized controlled trial”, where the patients were followed over four periods of time and distributed by randomization into an experimental group and a control group. The sample size consisted of a total of 42 patients. As the considered intervention, the patients from the experimental group have viewed their personal CT-Scanner combined with the dosimetry associated with their personal treatment plan, thanks to the “Stone of Orthanc” software, together with explanations from the radiotherapist. The aim of the study was to measure the impact of the intervention according to Kirkpatrick's levels: satisfaction, feeling of involvement, perception of knowledge, feeling of to be prepared, therapeutic adherence and psycho-social impact (anxiety, depression and emotional distress). Two secondary objectives were aimed at the evaluation of the computer program and the indirect impact of the intervention on the nursing staff. Key elements of the critical analysis: The data collection had to be prematurely stopped because of the COVID-19 crisis. Nonetheless, this study highlights several positive, although non-significant results on the side of the experimental group, in particular an improvement of knowledge and a reduction of the psychosocial impacts. As a consequence, the use of medical imaging could bring added value through the individualization of the content and its ability to create and internalize cognitive links, thus developing the skills of the patient. [less ▲]

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See detailAdvances in survival analysis methods and applications to the banking industry
Beretta, Alessandro ULiege

Doctoral thesis (2020)

The structure of the commercial bank industry in the United States changed considerably over the last four decades. The number of institutions insured by the Federal Deposit Insurance Corporation (FDIC ... [more ▼]

The structure of the commercial bank industry in the United States changed considerably over the last four decades. The number of institutions insured by the Federal Deposit Insurance Corporation (FDIC) shrunk by almost two-thirds due to failures and mergers & acquisitions occurred during the Savings and Loan and the subprime mortgage crises. Since bankruptcies may have severe consequences on the whole financial sector and the real economy, it is important for regulators to identify which factors lead banks into financial distress and to estimate their default risk. In this thesis, we present methodological advances in survival analysis, i.e. the statistical analysis of time-to-event data. First, we consider a location-scale regression model and we propose goodness-of-fit tests for the conditional mean and variance. Then, we focus on a more complex semi-parametric cure model, which allows researchers to handle situations where a portion of the population under investigation is likely to be immune to the event of interest. We extend it to time-varying covariates and we provide a variable selection technique based on its penalized-likelihood. To this effect we developed the penPHcure R package, which latest release is available on CRAN. Finally, we propose the use of Generalized Extreme Value regression to model the incidence distributions in a competing risks framework. In support of further research, we believe that these methods could be applied beyond the field of management science. For example, in medicine, to address the current Coronavirus outbreak, spawning novel scientific collaborations to help mitigate the worldwide blow from COVID-19. [less ▲]

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See detailFirst principles study of rare-earth nickelates: from bulk to heterostructures
Mercy, Alain ULiege

Doctoral thesis (2020)

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See detailChorégraphies néolibérales. La disciplinarisation des ONG de développement belges.
Contor, Justine ULiege

Doctoral thesis (2020)

Cette thèse propose d'analyser le processus de transformation du secteur des ONG de développement belges, durant ces 20 dernières années, à travers une généalogie des dispositifs de gouvernement. Nous ... [more ▼]

Cette thèse propose d'analyser le processus de transformation du secteur des ONG de développement belges, durant ces 20 dernières années, à travers une généalogie des dispositifs de gouvernement. Nous montrons dans ce travail empirique que les ONG de développement belges sont disciplinées par une série de dispositifs de gouvernement gestionnaires s'inscrivant dans un contexte néolibéral. Nous montrons à travers trois cas empiriques (généalogie des dispositifs, analyse des acteurs intermédiaires des ONG et ethnographie au coeur d'une ONG) que ces dispositifs transforment profondément l'ensemble du secteur, les ONG en tant qu'organisations mais aussi les travailleurs. Cette analyse révèle tout d'abord, que les ONG, leurs travailleurs, et l'administration de la coopération voient leurs modalités d'existence transformées au contact de ces dispositifs. Ce travaille montre ensuite les modes de résistances mis en place par les acteurs eux-mêmes. Ainsi, les dispositifs ne s'imposent pas ils se négocient comme le feraient deux partenaires de danse dans une chorégraphie (néolibérale). [less ▲]

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See detailModelling of drying phenomena in concrete with recycled aggregates
Fanara, Arthur ULiege

Master's dissertation (2020)

Concrete is the most used building material in the construction industry, with a production estimated to be about 1 billion tons/year in the European Union. Natural aggregate (NA) is one of the main ... [more ▼]

Concrete is the most used building material in the construction industry, with a production estimated to be about 1 billion tons/year in the European Union. Natural aggregate (NA) is one of the main ingredients of concrete, whose production reached about 2.8 billion tons in Europe in 2017. It is today evident that natural aggregates and sand are becoming a scarce resource and their availability becomes therefore an important challenge. Furthermore, environmental concerns regarding the construction industry have risen, particularly regarding CO2 emissions and waste production from construction and demolition activities (C&D Waste). That’s why the construction industry needs to develop and implement processes able to incorporate recycled products into its building materials. Recycled Concrete Aggregates (RCA) produced from crushed C&DW as a replacement of natural aggregates is one of those solutions which has made it a thoroughly studied field. RCA consist of coarse particles containing natural aggregates as well as residual cement paste which impairs negatively their properties compared to NA. Indeed, the use of RCA inside concrete increases the porosity and may therefore reduce its durability. The focus of this master thesis is to analyse the influence of RCA on transfer properties (water retention curves, permeability and porosity) and drying behaviour of concrete. Indeed, a better knowledge of those properties will help to determine the effect of RCA on the durability of concrete as water and vapour transfers are the necessary condition to observe degradation processes like carbonation, chloride ion diffusion or alkali-aggregate reaction. A numerical model for drying phenomena of concrete samples with recycled aggregates is developed in this thesis. To support this modelling, an experimental programme with sorption and desorption tests as well as porosity and permeability determination, is implemented. To better study the influence of the RCA alone, several concrete mixes are studied: a reference composition with natural aggregates and the same composition with RCA (same granulometric curve), a mix with natural aggregates but another cement type and, finally, a mortar without any aggregates. The three concrete compositions have the same paste content and type as it highlights the influence of the change of aggregates/cement type. The modelling is performed with a nonlinear finite element software developed at the University of Liège (called Lagamine). It follows the theory of nonlinear finite elements modelling of flows in porous media and consists of a coupled thermo-hydraulic study of the material. An application is also carried out in the form of an exterior parking lot's column subjected to real outdoor conditions: at constant and variable temperature, the relative humidity will vary between 40% and 95%, with multiple cycles of 6 months. Results show that, as predicted, concrete made from Recycled Concrete Aggregates (RCA) is more porous than its Natural Aggregates (NA)-based counterpart. Its water absorption and intrinsic permeability are also superior than for regular concrete. In terms of water retention properties, both concretes are similar, with no significant differences. The first indicator of durability measured in this thesis is the resistance to carbonation, which showed that concrete made from RCA is more prone to carbonation than concrete with NA. Nota Bene: this master thesis has been performed during the COVID-19 period when lockdown was applied from March 19th to May 31st, 2020. [less ▲]

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See detailMigrant workers in industrial zones and return migration: Case studies in Que Vo and Yen Phong industrial zones of Bac Ninh province and Van Thang commune of Nong Cong district, Thanh Hoa province, Vietnam
Ngo Trung Thanh, ULiege

Doctoral thesis (2020)

It is clear that the important role of labor migration in development reflected through the impacts of remittance currently exists in many countries around the world. The complexed nature of migration ... [more ▼]

It is clear that the important role of labor migration in development reflected through the impacts of remittance currently exists in many countries around the world. The complexed nature of migration that needs to interpret in a dynamic context and a changing society. Reviewing literature demonstrates the discourses of the motives of migration across many migration theories. Then, there are plenty of discussions of the motives of migration added from empirical research. However, there is still a lack of literature that requires discussion on why the domestic migrants leave their homes to work at places considered as exploitative and degrading, like industrial zones. In addition, migration is understood as an in and out process. Attempts have been made to explain the motive of out-migration, but few ones focus on return migration. Furthermore, existing literature focuses more on international return migration than internal return migration and the theories of return migration are subject to various debates. Since 1975, after the reunion of Vietnam, the government enforced a policy to restructure the population which led to inter-province migration. Many studies have been conducted on migration ever since, but few focused on return migration. This research survey 310 migrant workers in Que Vo and Yen Phong industrial zones of Bac Ninh province, and 68 returnees in Van Thang commune, Nong Cong district, Thanh Hoa province of Vietnam. Face to face interviews with two designed questionnaires have been applied to those samples. One is for migrant workers and the other is for returnees. Besides, some qualitative methods are also applied for supplementing the data collected by the questionnaires. Through those principle methods, this study found that the motives of migrant workers are complex. Push and pull theory by itself is not enough to explain these motives. The addition of the new economic theory of migration labor has made the explanation of migration motives more complete. Also, the research illustrated that the factors pushing rural people outmigration are, firstly, the local shortage of non-agricultural jobs, causing migrant workers to find alternatives in Bac Ninh industrial zones. More importantly, there is a shortage of cash for daily consumption. This itself, agricultural production, a prominent feature of rural areas, cannot be solved. Interestingly, the economic status of the household before the migration is not considered clearly as a push factor. But, migration to industrial zones is the rural youths’ way of life. Experiencing in these zones aspires those people due to a life different from the areas of origin, acted as a pull factor. Furthermore, migrant workers are all attracted by high labor demand that created easier access to employment in the industrial zones of Bac Ninh. This study also found that social network acts as both push and pull factor for immigrating to the industrial zones. Furthermore, it revealed that migrant workers, a major labor force for industrial zones, now face challenges created by the unstable model of development. The sustainability of the development of industrial zones in Bac Ninh is threatened by the fact that these zones follow the footloose of their development model exposed in the 1990s. Additionally, this study found that migrant workers in industrial zones in Bac Ninh faced a trade-off between accepting a hard life and accumulating capitals as well as experiences for an expected better one afterward. Furthermore, the migration undertaken by migrant workers in industrial zones of Bac Ninh seems to be circular. Regarding return migration, this study demonstrated that the motive to return not only results from potential failures related to the increased living costs of the future married life but also associates with children left behind at the home village with stayers. Returnees are all driven by a filial obligation to their parents, shaped by the norms or culture of the home community. Non-farm employment opportunities around home villages are more of a motive to return for single migrants. This study also found that women play an important role in agriculture development in Van Thang. This sector is likely a buffer for the negative impacts of the return while the returnees seek better nonfarm employment around their home villages. [less ▲]

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See detailOn emigrant nationality
van der Baaren, Lucas Jan ULiege

Doctoral thesis (2020)

The position of States on dual nationality has gradually developed from hostility to tolerance, and is now possibly moving towards an embrace for one particular group of nationals, namely emigrants. This ... [more ▼]

The position of States on dual nationality has gradually developed from hostility to tolerance, and is now possibly moving towards an embrace for one particular group of nationals, namely emigrants. This dissertation describes how States have given shape to their nationality policies in order to remain connected with their diaspora, a phenomenon referred to as ‘emigrant nationality’. It presents an analysis of emigrant nationality policies of 196 States in order to determine to what extent States allow emigrants and their descendants to retain their original nationality, next to another nationality. In order to complement this broad analysis with an in-depth analysis, two country studies were conducted on emigrant nationality policies in Sri Lanka and Spain. The first country study describes how Sri Lanka grants dual citizenship certificates to a privileged segment of its emigrants in order to enable them to hold more than one nationality. The second country study shows how the Law of Historical Memory and the introduction of special nationality provisions for the Sephardim enabled Spain to reconnect with its diaspora even after a long period of time. The study shows that a large majority of States has come to accept dual nationality for emigrant populations, yet that its scope varies greatly. This means that even though the acceptance of nationality for emigrant populations is widespread, this acceptance has often remained partial and conditional. [less ▲]

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See detailEconomic analysis of small scale freshwater aquaculture production and its product marketing channels in agro-aquaculture system in Hai Duong province, Vietnam
Nguyen Van Huong, ULiege

Doctoral thesis (2020)

VAC stands for the first three letters of three words: Garden (V), pond (A), cage (C), referring to a smallintensively farming ecosystem model to solve the shortages of food and develop rural economy in ... [more ▼]

VAC stands for the first three letters of three words: Garden (V), pond (A), cage (C), referring to a smallintensively farming ecosystem model to solve the shortages of food and develop rural economy in Vietnam. It has been shaped and developed for nearly four decades since Vietnam finished the wartimes and reunification in 1975. At first, the VAC economy may seem to be small, and just a "informal economy". However, it has been soon become an important role for the strategy of self-sufficient food and economic development to overcome difficulties and hardships of transition period in the past. Since Vietnam approved the autonomous role of household economy after the revolution of “Doi Moi”, the VAC model has been widespread promoted and exploited by many local provincial authorities and farmers in over the country. Hai Duong province is one of the provinces, which has encouraged farm households to develop the VAC model since begin of the 1980s when it first was introduced in the Red River Delta in Vietnam. As impacted VAC ecosystem model, many types of fish farming have been practiced in Hai Duong where emerges to many zones of concentrated aquaculture production converted from rice fields. With the introduction of fish in the existing agricultural systems, farmers have diversified the farming practices in the optimal manner of land use to improve the nutritional food status, increase household income, and create more employment. This leads to the fish production becoming very diverse, complex and dynamic in Hai Duong province. The study has designed to understand the diversifications of the integrated small scale aquaculture (SSA) production models in the Red River Delta. The study results show that four models have been found such as single commercially-intensive fish production system (FS), Animal Fish system (AF), New VAC system and traditional VAC system with different characteristics. Despite these SSA models are differed from one another, they are all in favoured of producing food for farmers’ home consumption or/ and commercial products for cash income in parallel reduction the seasonal situation of unemployment in rural areas. Particularly, the economic efficiency of the SSA models has made a great contribution to improve the farm households’ economic condition in the rural in Hai Duong province, Vietnam. These freshwater SSA models are considerably dynamic and diversified by household strategies. In general, they have good efficiency in terms of job creation, food production, and economic benefits. The study also shows that the AF model has the highest economic return while the FS model obtains the lowest. The new VAC and traditional VAC models are significantly diversified to generate different sources of onfarm income. Whereas the new VAC model with a focus on high market value species has higher economic efficiency than the traditional VAC model. This reflects VAC can be developed to in a manner that can generate more cash income for the rural farm households in Hai Duong. Besides, the SSA models have been more intensified and developed the different species of marketable fish to supply to increasingly market demand, fish farmers have been being still faced to many challenges and difficulties of marketing their fish products such as lacks of outlets and marketing channels available at local markets, shortages of storing facilities, means of transportation, and market volatility. These problems require to more governmental interventions on both production and marketing to assist small scale aquaculture production to maintain as a strategic tool to develop the local economy as well as provide farm households a sustainable livelihoods. The supports might be focus on enhancing the production management skills, and market organized in both wholesale and retail markets that would be the most appropriate measures to facilitate the SSA models more developing in Hai Duong province. [less ▲]

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See detailL'expérience de création de jeux vidéo en amateur - Travailler son goût pour l'incertitude
Hurel, Pierre-Yves ULiege

Doctoral thesis (2020)

"La création de jeux vidéo est une importante pratique culturelle produisant des œuvres interactives et l’objectif de cette thèse est de rendre intelligible l’expérience de ses praticiens. La création de ... [more ▼]

"La création de jeux vidéo est une importante pratique culturelle produisant des œuvres interactives et l’objectif de cette thèse est de rendre intelligible l’expérience de ses praticiens. La création de jeux vidéo, parce qu’elle est traversée par le jeu et l’interaction, est un terrain de choix pour apporter une contribution originale aux études des pratiques culturelles. C’est là son principal intérêt scientifique, qui trouve son origine dans la situation nécessairement intermédiaire des amateurs. Ces derniers naviguent entre jeu, création de jeu et jeu de création. Il y a alors une occasion unique de revisiter, au-delà même du jeu vidéo, notre compréhension des productions amateur : les « joueurs » sont-ils les seuls à jouer ? Les photographes et les cinéastes ne semblent pas être les derniers à jouer avec leurs appareils : mais alors à quoi jouent-ils ? Et qu’est-ce que ce jeu nous dit de leur processus créatif ? Nous apporterons au moins deux réponses, qui se rejoignent et qui imprègnent cette recherche de manière transversale. D’abord, c’est que l’acte de jouer est un acte intime nécessairement orienté vers le joueur lui-même. On ne joue jamais que pour soi (et pourtant, parfois, ce faisant, on crée pour un autre). Ensuite, c’est qu’il n’y a pas de jeu sans amour, ou du moins sans plaisir. On mettra à l’épreuve, dans ce travail, un critère définitoire du jeu aussi évident que délaissé, et loin d’être simple à étudier : si l’on joue, c’est par goût. Aussi, quand les amateurs créent du jeu, ils continuent de travailler leur goût. Mais, à nouveau : on ne peut jamais goûter que pour soi-même. Jouer et goûter : tout nous ramène à un faire pour soi dont l’articulation à un faire pour l’autre s’annonce problématique. Nous touchons là à l’ambition de ce travail : comprendre un agir culturel qui est profondément intime et personnel, sans abandonner la compréhension de ses modalités de partage – structurellement et nécessairement complexes." (page 7) [less ▲]

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See detailDeveloping decision-support tools with economic and environmental interests for the dairy sector using milk mid-infrared spectrometry
Delhez, Pauline ULiege

Doctoral thesis (2020)

Maintaining satisfying economic outcomes and limiting environmental impacts are key challenges in dairy farming today and this requires good decision-making regarding actions to make on farms. The ... [more ▼]

Maintaining satisfying economic outcomes and limiting environmental impacts are key challenges in dairy farming today and this requires good decision-making regarding actions to make on farms. The analysis of milk by Fourier-transform mid-infrared (MIR) spectrometry provides valuable information on milk composition. This technique has already demonstrated qualities to support decision-making, for example, through the well-established predictions of milk fat and protein contents or the latest development of prediction models for novel traits. However, its full potential remains partly uninvestigated. Hence, the objective of this thesis was to contribute to the development of decision-support tools with economic and environmental interests for the dairy sector using milk MIR spectrometry. The research conducted in the framework of this thesis covered three different approaches of using MIR for decision support: (1) the development of a MIR calibration equation to predict a trait of interest, (2) the development of a test-day model to predict milk MIR spectra for management purposes, and (3) the combination of MIR-predicted data with other data streams as a means of providing additional information for decision-making. First, we explored different strategies to predict the pregnancy status of dairy cows (pregnant vs. open) in Australia using milk MIR spectra and partial least squares discriminant analysis. Correctly identifying the pregnancy status of cows is imperative for a profitable dairy farm. Early pregnancy could not be detected satisfactorily, but promising results were obtained using MIR spectra recorded 151 days or more after insemination (i.e., mid- and late gestation), with the area under the receiver operating characteristic curve of 0.76 on the testing set. A potential application that needs to be explored further is the development of a screening tool to detect mid- to late-term fetal abortion. Secondly, we studied the ability of a test-day mixed model to predict milk MIR spectra from first parity Holstein cows for management purposes (e.g., for the detection of problems, simulations, predictions of future data). The spectral data used for modeling originated from the Walloon milk recording database. The average correlation between observed and predicted values of each spectral wavenumber was 0.85 for the modeling set and ranged from 0.36 to 0.62 for different scenarios that corresponded to situations with more or less information known about the cows. Correlations between milk fat, protein and lactose contents predicted from the observed spectra and from the modeled spectra ranged from 0.83 to 0.89 for the modeling set and from 0.32 to 0.73 for the scenarios. These results demonstrated a moderate but promising ability to predict milk MIR spectra using a test-day model. Different improvements of the model are possible before potential practical applications that could have economic or environmental implications for dairy farming, depending on the MIR traits subsequently predicted from the modeled spectra. Thirdly, we investigated the univariate relationships (correlations) between dairy cow enteric methane (CH4) production (g/day) predicted from milk MIR spectra and 42 technico-economic variables from 206 Walloon dairy herds over a period of 8 years. Enteric CH4 is an important part of the carbon footprint of milk production. Significant correlations ranged between |0.06| and |0.38|. Low MIR CH4 production tended to be associated with more extensive or suboptimal management practices, which could lead to lower profitability. The observed weak correlations suggest intricate interactions between MIR CH4 and technico-economic variables due to the use of real farm data with large variability in management practices. This implies the need for further research to unravel these complex relationships for a better understanding of factors associated with CH4 production on dairy farms in order to better target mitigation strategies. Lastly, we discussed, in the light of the research carried out in this thesis, strengths as well as issues and considerations regarding the development of decision-support tools using milk MIR. In particular, key strengths of MIR are the low cost and rapidity of the technology as well as the standard procedures for milk sample collection and analysis, allowing the acquisition of MIR data on a large scale for the development of various customized tools to assist decision-making on dairy farms. Issues and considerations covered the prediction of indirect MIR traits, the quality and variability of spectral and reference data, the choice and validation of models, the utilization of MIR indicators, the study of MIR traits in the population, the timing of milk sampling, and the uptake of MIR tools by farmers. In conclusion, this thesis contributed (1) to establish the first steps of the development of new MIR tools and studies to support decision-making in dairy farming with potential economic and environmental benefits; and (2) to gain insight into the benefits and considerations of using milk MIR for the development of decision-support tools. [less ▲]

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See detailLe nouvel esprit de l’université : une institution au défi de la troisième mission
Hoerner, Céline ULiege

Doctoral thesis (2020)

This thesis focuses on the evolution of the university in French-speaking Belgium since the European reforms of the end of the 20th century (Sorbonne declaration, Bologna process, Lisbon strategy). We ... [more ▼]

This thesis focuses on the evolution of the university in French-speaking Belgium since the European reforms of the end of the 20th century (Sorbonne declaration, Bologna process, Lisbon strategy). We start from the observation that universities are now subject to injunctions from the New Public Management and more broadly from managerial ideology, but also to constraints linked to the context of underfunding of higher education in the Wallonia-Brussels Federation. We will see that in addition to the market constraints, the university must also respond to the expectations of society, leading to a new reconfiguration of knowledge. The aim of this research is to study how the university responds to the injunctions of profitability and transparency addressed to it as well as to society's expectations. We analyse to what extent and how the notion of third mission and the activities related to it contribute to the university's response to the requests addressed to it. As part of this work, the University of Liège constituted our main research field while two other so-called "complete" universities of the Wallonia-Brussels Federation were studied to a lesser extent (the “Université Libre de Bruxelles” and the Catholic University of Louvain). Our method is qualitative, based on the one hand on the analysis of institutional discourse and on the other hand on semi-structured interviews conducted with actors in the academic world, but also outside it. Our observations show that the idea of a third mission covers both service to society, as it can be defined in the literature, as well as the service to the university community. However, for those working in the field, the definition of the third mission remains unclear and unequivocal. We propose a modelling of the third mission by studying different services and devices of the university as boundary objects between the university and other actors outside it. The analysis of the university through the prism of the City by projects and the perspective of a networked world makes the third mission perceived as a way of legitimizing the institution in relation to the injunctions emitted from European reforms, but also as a response to society's requests. [less ▲]

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See detailEtude de la mise en place des services pérennes de vaccination animale en milieu rural en République Démocratique du Congo : Cas de lEtude de la mise en place des services pérennes de vaccination animale en milieu rural en République Démocratique du Congo : Cas de la maladie de Newcastle dans trois provinces du Sud-Ouest
Lwapa Embele Isenge, Francis ULiege

Doctoral thesis (2020)

The Democratic Republic of Congo (DRC) has a population living mostly in rural areas (70%). Most of this rural population (80%) are agro-pastoralists. For these households, livestock farming constitutes a ... [more ▼]

The Democratic Republic of Congo (DRC) has a population living mostly in rural areas (70%). Most of this rural population (80%) are agro-pastoralists. For these households, livestock farming constitutes a form of on-farm savings that can be mobilized in case of need. Endemic infectious diseases that can be prevented by vaccination regularly threaten the main domestic animal species kept by these households. Furthermore, following the evaluation of the Performance of the Veterinary Services of DRC carried out by the OIE in 2011, these diseases, in particular the Newcastle disease in chickens, the peste des petit ruminants, the foot-and-mouth disease, the contagious bovine pleuropneumonia, anthrax and blackleg in ruminants and rabies in dogs, were ranked as priorities. At the dawn of the year 2020, no systematic control measures for these diseases had been taken at the national level. The establishment of sustainable animal vaccination services in DRC is an urgent necessity. In this situation, one way of establishing effective and sustainable vaccination services would be to establish schemes for recovering costs of vaccination from the users of the services. This doctoral research investigates the appropriateness and modalities of setting up paid animal vaccination services in a rural Congolese context marked by poverty and difficult access. Semi-structured individual interviews (SSII), focus group discussions (FGD) and stated preference surveys were used across four studies to identify the requirements for the implementation of animal vaccination services based on the user-pay principle and the One Health (OH) approach. This study used the vaccination of village chickens against Newcastle disease in three provinces of the southwestern part of DRC as a case study. This vaccination used the I-2 ND vaccine produced locally by the Kinshasa Veterinary Laboratory. This vaccine is thermostable and can be administered by eye drop. To conduct a participatory evaluation of the paid vaccination campaigns of village chickens against Newcastle disease in Kongo Central province, 12 FGD and 160 SSII were organized in four sites (study 1). This participatory process led to the design of a grid for evaluating the performance of animal vaccination services. In order to analyze the demand for paid animal vaccination services, identify preferences and understand the behavior of livestock keepers, a discrete choice experiment was carried out in eight sites out of 320 livestock keepers (study 2). To carry out a participatory evaluation of the value of OH approaches in the development of animal health services in DRC, 15 FGD and 100 SSII were conducted among professionals from Environmental Services (ES), Veterinary Services (VS) and Public Health Services (PHS) in five territories in three provinces (study 3). The expectations and benefits identified by the Congolese stakeholders were compared to the benefits of the OH approach as currently theorized in the scientific literature. This step was followed by the development of an evaluation protocol adapted from the one proposed by the Network for Evaluation of One Health (NEOH). In order to evaluate the synergy between village chicken vaccination networks and public health vaccination networks, 12 FGD and 288 SSII were conducted in six public health zones in three selected territories (study 4). The evaluations of 15 vaccination networks run by Community-Based Health Workers (CBHW) and 15 networks run by public veterinarians were carried out separately on the basis of the evaluation grid proposed by study 1. The results of the two evaluations were then compared. The assessment grid highlighted four strengths in favor of the sustainability of the paid vaccination service for village chickens organized by the Centre Agronomique et Vétérinaire Tropical de Kinshasa (CAVTK) in Kongo Central province. These were the interest expressed by chicken keepers, the perceived efficacy of the vaccine, the availability of the vaccine and the ease of vaccine use. Two weaknesses were identified, namely the poor access of chicken keepers to information and the low motivation of vaccinators. According to the assessment grid developed in this study, the paid vaccination campaign for village chickens in Kongo Central province obtained a performance score of 62.8%, with a diversity of scores between zones (study 1). Farmers preferred a paid vaccination service for village chickens, carried out according to an imposed calendar and administered by a public veterinarian (study 2). SV, SE and PHS professionals in DRC identified four of the eight benefits of the OH approach as described in the literature. Application of the adapted protocol for evaluating the OH approach showed that in DRC, there is a strong implantation of OH thinking and the OH sharing spirit, but a low level of OH learning, OH planning and OH working in the field (study 3). CBHW and veterinarians encountered the same difficulties in the field. CBHW felt that their involvement in the vaccination of village chickens had changed the collaborative relationship between the VS, ES and PHS. In general, according to the assessment grid established here, CBHW scored better (84±3%) than public veterinarians (76±8%). However, only vaccine efficacy criterion showed a significant difference. Furthermore, CBHW teams had achieved an average activity radius of 43.5±30.5 km and public veterinarians an average activity radius of 6.6±4.0 km. The priorities for improving the animal vaccination service seem to be awareness raising among animal keepers and increasing the motivation of vaccinators. The profile of paid animal vaccination service should be adapted to the expectations of farmers while meeting the technical requirements of vaccination. The public veterinarian will supervise the vaccination activities, which will be implemented by trained CBHW, through collective campaigns at fixed periods of the year. The acceptable price would allow the service to be fixed on a sustainable basis and could be increased if confidence in the service provided increases. In the DRC, the professionals of the VS, ES and PHS were willing to work together to reinforce each other and to achieve their common ideal, which is the well-being of the communities they serve. The success of such an approach would require the rejuvenation of veterinary staff in rural areas and the assignment of qualified veterinary professionals capable of designing and co-managing joint activities with the managers of ES and PHS. The results of this thesis showed that village chicken keepers in these three provinces have adopted the user-pay principle for organizing the vaccination of their chickens. The amount collected by the vaccination services could contribute to the partial financing of vaccination activities. It will be used on the one hand to renew vaccine stocks and on the other hand to pay the vaccinators. The performance achieved by CBHW in vaccinating village chickens is proof that the OH approach can help VS to set up sustainable animal vaccination services in DRC. It will be able to solve the problem of sensitization among animal keepers, motivating vaccinators and the lack of human resources. It will provide a partial solution to the cold chain problem. The financial and material resources provided by the CAVTK and the research funds of this thesis have shown that DRC’s veterinary services need to develop a public-private partnership (PPP) for the implementation of activities in favor of animal health. Such a partnership could help these services to boost animal vaccination by making vaccines and cold chains available at the local VS. The failures of vaccination of village chickens observed in some places have shown that the implementation of sustainable animal vaccination services in DRC must not only face organizational, logistical and financial obstacles but must also prevent biological causes of vaccination failures. These failures will have an impact on animal keepers' appreciation of the vaccine's effectiveness and will reduce the rate of adoption of vaccination by them. On the organizational, logistical and financial level, this study showed that three pillars, namely user-pays principle, One Health approach and public-private partnership, could ensure the financing, sustainability and logistics of these services as well as the accessibility of these services to a significant number of animal keepers in the country. Laboratories must be involved upstream of animal vaccination in order to find appropriate vaccine strains, to determine the vaccination status of the herds to be vaccinated, to diagnose possible immunosuppressive diseases in the herds concerned and finally to develop appropriate vaccine strategies. It is also important that support programs be set up to teach animal keepers good animal husbandry practices and biosecurity measures. These are the conditions for an animal vaccination to be effective and for the proposed services to be organized in a sustainable way. [less ▲]

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See detailNumerical modeling of friction in lubricated cold rolling
Boemer, Dominik ULiege

Doctoral thesis (2020)

Thinner and harder steel strips, which are in great demand in the production of lighter car bodies, challenge cold rolling mills like never before. The objective of this thesis is therefore to accurately ... [more ▼]

Thinner and harder steel strips, which are in great demand in the production of lighter car bodies, challenge cold rolling mills like never before. The objective of this thesis is therefore to accurately model friction in lubricated cold rolling to ultimately minimize friction while preventing skidding between the rolls and the strip by flexible lubrication, i.e. by adjusting the lubrication conditions in real-time depending on the current rolling conditions. Accordingly, the most comprehensive experimental data of lubricated cold rolling are analyzed to identify the underlying physical mechanisms that have to be included in the rolling model. Furthermore, these data are post-processed to test this model. By means of the previous data, the most powerful model of lubricated cold rolling available so far is completely rederived, documented, and improved while its computer implementation is entirely refactored. This model, which is called Metalub, is a 2D cold rolling model in the mixed lubrication regime with a thermo-elastoviscoplastic description of the strip, a thermo-piezoviscous description of the lubricant, non-circular roll flattening and lubricant starvation. In particular, strain rate hardening and thermal softening are added to the model in addition to improvements regarding its robustness. Metalub is then tested based on the previous experimental data to evaluate its predictive capabilities and shortcomings. After the first systematic calibration of its numerical parameters, this model allowed to improve predictions of earlier research by more physically consistent hypotheses. Nevertheless, the model is still limited by unavailable material parameters, the simplicity of its thermal model as well as manual adjustments of the lubricant film thickness and the boundary coefficient of friction, if starvation or micro-plasto-hydrodynamic/static (MPH) lubrication (permeation of the lubricant from microscopic surface pockets into the solid/solid contact zone between asperities) occur, respectively. Thus, the first coupling procedure between Metalub and the finite element (FE) solver Metafor is developed to replace analytical asperity flattening equations by FE simulations of lubricated asperity flattening and to ultimately include MPH lubrication in the model. Finally, lubricated asperity flattening is for the first time simulated by the Lagrangian meshless particle method "smoothed particle hydrodynamics" (SPH) to eliminate mesh-related weaknesses of FE asperity flattening models. [less ▲]

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See detailCultiver les territoires. L'innovation participative à la Commission européenne et en Wallonie
Macq, Hadrien ULiege

Doctoral thesis (2020)

Innovation ouverte, incubateurs de start-up, hackathons, hackerspaces … Les pratiques des hackers et makers calforniens, bidouillant de nouvelles technologies dans leurs garages de la Silicon Valley ... [more ▼]

Innovation ouverte, incubateurs de start-up, hackathons, hackerspaces … Les pratiques des hackers et makers calforniens, bidouillant de nouvelles technologies dans leurs garages de la Silicon Valley, semblent s’être répandues en Europe. Les processus de recherche et de développement technologique, l’innovation, apparaissent ainsi de plus en plus ouverts, participatifs. Cependant, alors que le mouvement maker en Californie s’est développé au travers d’une critique des institutions en place, qu’elles soient économiques ou politiques, ce qui se joue en Europe semble être d’un autre ordre. En effet, le développement de technologies par les citoyens y semble a priori articulé à une ambition de développement économique, au sein de discours insistant sur la notion d’économie de la connaissance. En d’autres termes, ce que le développement de pratiques d’innovation participative en Europe semble montrer, c’est que des pratiques fréquemment assimilées à un mouvement contre-culturel sont reprises et adaptées, dans d’autres contextes, à des ambitions politiques de développement économique et d’entrepreneuriat. Dans les deux cas, l’inventivité et la créativité sont érigées au rang d’impératifs. Cependant, alors que cet impératif est véhiculé par des communautés de pratiques grassroots dans la Silicon Valley, sans autre finalité que sa propre complétion, il est véhiculé par des autorités publiques dans le cas de la Commission européenne et de la Wallonie, articulé à des programmes politiques d’économie et d’innovation. Comment dès lors ces pratiques se développent-elles dans ces contextes ? Comment s’intègrent-elles à des politiques d’innovation qui leur préexistent ? Qui participe aux processus participatifs de recherche et d’innovation, à partir du moment où ils sont promus et mis en place par des autorités publiques ? Ce sont ces questions qui ont guidé la présente thèse, qui propose une analyse de l’innovation participative telle qu’elle est promue et qu’elle se déploie à la Commission européenne et en Wallonie. [less ▲]

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See detailIn vitro study of the impacts of exposure to mixtures of endocrine disrupting chemicals on the aryl hydrocarbon and steroid receptor transcriptional activity
Doan, Thi-Que ULiege

Doctoral thesis (2020)

Chemicals are undoubtedly important and beneficial for our modern life. As a result, we are exposed to mixtures of chemicals in our daily life through applying them for food production and preservation ... [more ▼]

Chemicals are undoubtedly important and beneficial for our modern life. As a result, we are exposed to mixtures of chemicals in our daily life through applying them for food production and preservation and for supporting human and animal health and recreation. However, risk assessment for the consumer is usually based on a chemical-by-chemical approach. Among these chemicals, endocrine disruptors (EDs) are of concern, in particular because they are able to alter the function(s) of the endocrine system, leading to adverse health effects in organism or (sub) population levels. In vitro Chemically Activated LUciferase gene eXpression (CALUX) assays involving several transgenic reporter cell lines are interesting tools to study the impacts of exposure to mixtures of EDs and their components on the transcriptional activity of the master xenobiotic receptor, which is the aryl hydrocarbon receptor (AhR), as well as the steroid (estrogen (ER), androgen (AR), progesterone (PR), and glucocorticoid (GR)) receptors. Three mixtures were being investigated as examples of compound groups of human everyday exposure to chemicals: (1) the “total POP mixture” consisting of 29 POPs (persistent organic pollutants) prevalent in Scandinavian human blood, (2) the “ED mixture” containing 18 potential EDs dominantly found in Wallonia raw water intended for drinking water production, and (3) the “polyphenol mixture” containing seven food-based polyphenols. The concentration of each component in the mixture was based on human-relevant exposure such as fold human blood level (the POP mixture), fold maximum quantified concentration in raw water (the ED mixture), or fold recommended intake dose from food supplements (the polyphenol mixture). Specific aims of the project were: (a) evaluating species (rat and human) and/or tissue-specific (hepatocytes and mammary gland) AhR responses to the POP mixture and the polyphenol mixture and their components, (b) profiling the endocrine disrupting activities of the EDs and the mixture thereof prevalent in raw water using AhR and steroid receptors, (c) identifying interactions among the chemicals (additive, antagonistic or synergic effects) on the transcriptional activity of the receptors, (d) identifying the actual chemical(s) the most active in the mixtures, and (e) predicting the effect of the mixtures based on the activity of single compounds. The results showed that 16 out of 29 POPs contaminating human blood were AhR antagonists. The total POP mixture also showed an AhR antagonistic activity although it contained each compound at the concentration below its lowest-observed-effect concentration (LOEC). Chlorinated compounds were the drivers of the activity of the total POP mixture, among which PCB-118 and PCB-138 contributed for 90% of the total POP mixture effect. From the 18 EDs prevalent in raw water, chlorpyrifos, bisphenol A, fluoranthene, phenanthrene, and benzo(a)pyrene demonstrated significant activities on several receptors. Noticeably, benzo(a)pyrene mixed with dioxin TCCD induced a synergistic response in AhR- i reporter human mammary gland cells (DR-T47-D), 10-fold higher than the cells’ response to TCDD alone, at a concentration which could be a realistic blood level after a food contamination incident or in a high exposed sub-population. The mixture of the 18 EDs compounds exerted AhR and ER agonistic activities, which can be explained by the activities of benzo(a)pyrene and bisphenol A in the mixture. While the rat AhR reporter cells (DR-H4IIE) was more sensitive to POP exposure, we showed for the first time that the AhR endogenous ligand FICZ, a tryptophan derivative was more potent than TCDD in the human AhR (DR- HepG2) (40 times more potent than TCDD) while both exhibited a similar potency in the rat cells (after 6h exposure). Two isoflavones (daidzein and genistein) induced a higher AhR agonistic/synergistic activity in the rat cells, while the others (a flavonol (quercetin) and two flavones (baicalin and chrysin), curcumin, and the mixture of the seven polyphenols) caused a stronger AhR antagonistic response in the human cells. Quercetin and resveratrol were the strongest AhR antagonists in the human cells, which contributed most for the antagonistic activity of the polyphenol mixture. Dose-response curves were predicted successfully by concentration addition and general concentration addition models for the POP mixture, while both concentration addition and independent action performed well for estimating the effect of the polyphenol mixture, indicating the additive activity of the components in these mixtures. The results suggested that the endocrine disrupting activities of chemicals in human daily life exposure could involve more than one mechanism: their (anta-) agonistic effects on different receptors with the potential for additive, inhibitory or synergistic effects of mixtures thereof should be considered in risk assessment. [less ▲]

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See detailPatient-Specific Metabolic Variability and Precision Glycaemic Control in Critical Care
Uyttendaele, Vincent ULiege

Doctoral thesis (2020)

Critically ill patients often experience stress-induced hyperglycaemia. Elevated blood glucose levels are associated with increased morbidity and mortality. Glycaemic control demonstrated improved ... [more ▼]

Critically ill patients often experience stress-induced hyperglycaemia. Elevated blood glucose levels are associated with increased morbidity and mortality. Glycaemic control demonstrated improved outcomes for these patients. However, other studies failed to replicate the results, primarily blaming the increased risk of hypoglycaemia and glycaemic variability, both associated with worse outcomes. These confounding outcomes have resulted in acceptance of hyperglycaemia and reduced outcomes, causing ongoing debate on glycaemic control. The goal of the thesis is to define what makes glycaemic control hard to achieve safely, prove safe, effective control impacts patient outcome, and demonstrate it is possible to achieve safe, effective control for all patients, despite targeting lower glycaemic ranges. Metabolic variability is the main factor making glycaemic control hard to achieve safely. More specifically, sudden changes in patient-specific response to insulin (intra-patient variability) can lead to severe hyper- and hypo- glycaemia. Novel analysis of model-based insulin sensitivity and its variability clearly showed while inter-patient variability can be significantly different across patients, intra-patient variability is equivalent. Therefore, no patient is harder nor easier to control, and thus all patients should be able to benefit from similar quality of control. In turn, conclusions on glycaemic control from studies failing to do so may be biased due to poor protocol design, rather than physiological factors related to severity and outcome. Intra-patient variability is still very large, and it is not possible to discriminate more and less variable patients, reducing the quality of control deliverable in practical clinical scenarios. This research developed a novel 3D stochastic model to optimally segregate more and less variable patients based on prior behaviours. This approach enabled significantly improved, and tighter prediction of risks associated with a given insulin and/or nutrition intervention. Clinical trial results in NZ have shown improved control and safety using this new 3D stochastic model. To demonstrate these outcomes, a clinical trial using STAR, a model-based, patient-specific glycaemic control framework, was designed and implemented at the University Hospital of Liège. Results showed STAR succeeded in providing safe, effective control to virtually all patients, despite targeting lower target bands associated with better outcomes. However, increased workload compared to the standard protocol was identified as a limitation. Finally, this thesis develops a means to dramatically increase the STAR measurement interval from 1-3 hourly to 1-6 hourly without significantly degrading performance or safety. Virtual trials clearly defined the risk and reward trade-off between control performance, patient safety, workload, and nutrition. This result allows clinical staff to choose from a far wider range of options and approaches to provide safe, effective control, with clearly defined risk trade-offs. Overall, a series of analyses and clinical trials have shown safe, effective control is necessary to improve outcomes, and can be achieved for all patients. These outcomes are possible using patient-specific, model-based glycaemic control protocols developed in this thesis, which directly account for both intra- and inter- patient variability and reduce workload. [less ▲]

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