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See detailPB 8783: the first sdO star suitable for asteroseismic modeling?
Van Grootel, Valérie ULiege; Randall, Suzanna K.; Latour, Marilyn et al

E-print/Working paper (in press)

Pulsating hot B subdwarfs (sdB) have become one of the showcases of asteroseismology. Thanks to the combination of rich observed pulsation spectra and state-of-the-art modeling tools it is possible to ... [more ▼]

Pulsating hot B subdwarfs (sdB) have become one of the showcases of asteroseismology. Thanks to the combination of rich observed pulsation spectra and state-of-the-art modeling tools it is possible to tightly constrain fundamental parameters such as the stellar mass for these compact, evolved objects in the core He-burning phase of evolution. In comparison, the exploitation of sdO pulsators - hotter stars thought to be in a more advanced evolutionary stage - is still in its infancy. While a small number have been identified in Globular Clusters (GCs), they are extremely rare among the field population. It was recently suggested that PB8783, one of the very first sdB pulsators discovered in 1997, may in fact be an unrecognized hot sdO star with very similar properties to the GC sdO pulsators. Here, we present new very high-quality spectroscopy as well as an asteroseismic analysis of this star with the aim of solving the mystery of its nature. [less ▲]

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See detailModels of Law and Regulation for AI
De Cooman, Jérôme ULiege; Petit, Nicolas

E-print/Working paper (2020)

This paperdiscusses models of law and regulation of Artificial Intelligence (“AI”). The discussion focuses on four models: the black letter model, the emergent model, the ethical model, and the risk ... [more ▼]

This paperdiscusses models of law and regulation of Artificial Intelligence (“AI”). The discussion focuses on four models: the black letter model, the emergent model, the ethical model, and the risk regulation model. All four models currently inform, individually or jointly, integrally or partially, consciously or unconsciously, law and regulatory reform towards AI. We describe each model’s strengths and weaknesses, discuss whether technological evolution deserves to be accompanied by existing or new laws, and propose a fifth model based on externalities with a moral twist. [less ▲]

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See detailCeramica comune da mensa e da dispensa di Roma
Dienst, Simon ULiege

E-print/Working paper (2020)

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See detailCeramica da cucina di Roma
Dienst, Simon ULiege

E-print/Working paper (2020)

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See detailI want to be an Open Scientist! Research evaluation and incentives to boost Open Science and research careers
Tanlongo, Federica; O’Neill, Gareth; Kurapati, Shalini et al

E-print/Working paper (2020)

Everybody is talking about Open Science and FAIR data but can you really make a living (and a good career) out of it? Will my career get better if I FAIRify my data? Or will it just make my head ache ... [more ▼]

Everybody is talking about Open Science and FAIR data but can you really make a living (and a good career) out of it? Will my career get better if I FAIRify my data? Or will it just make my head ache? When someone will evaluate my research, will the fact that my data complies with all the Open Science best practices matter? Or am I just losing time I should rather spend publishing on whatever journal I can lay hands on? And where am I supposed to learn how to be fair and open anyway? The right answer to these questions is crucial to the career choices and expectations of many students and young researchers, yes, but it is also the point which can make the difference between succeeding or failing in establishing Open Science (and ultimately Good Science). To be able to shift the research evaluation system in Europe in order to produce quality and reliable data, to set up a working incentive system for individual researchers and organisations is one of the keys to a widespread uptake of Open Science and FAIR practices. And being so crucial a point, we believe that researchers, Research Infrastructures, scientific organisations should have a say in this. That’s why we proposed an interactive session where good ideas, innovative pilots, proposed policies from all across Europe were presented and discussed. [less ▲]

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See detailConversation japonaise sur les bienfaits de la sémiotique
Badir, Sémir ULiege; Leone, Massimo

E-print/Working paper (2020)

Detailed reference viewed: 21 (1 ULiège)
See detailLa terre sigillée africaine - productions C, C/E et E
Dienst, Simon ULiege

E-print/Working paper (2020)

Detailed reference viewed: 22 (4 ULiège)
See detailLa céramique à vernis noir
Dienst, Simon ULiege

E-print/Working paper (2020)

Detailed reference viewed: 24 (3 ULiège)
See detailLa terre sigillée africaine - productions A, A/D et D
Dienst, Simon ULiege

E-print/Working paper (2020)

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See detailAllocation of locally generated electricity in renewable energy communities
Manuel de Villena Millan, Miguel ULiege; Mathieu, Sébastien ULiege; Vermeulen, Eric et al

E-print/Working paper (2020)

This paper introduces a methodology to perform an ex-post allocation of locally generated electricity among the members of a renewable energy community. Such an ex-post allocation takes place in a ... [more ▼]

This paper introduces a methodology to perform an ex-post allocation of locally generated electricity among the members of a renewable energy community. Such an ex-post allocation takes place in a settlement phase where the financial exchanges of the community are based on the production and consumption profiles of each member. The proposed methodology consists of an optimisation framework which (i) minimises the sum of individual electricity costs of the community members, and (ii) can enforce minimum self-sufficiency rates –proportion of electricity consumption covered by local production– on each member, enhancing the economic gains of some of them. The latter capability aims to ensure that members receive enough incentives to participate in the renewable energy community. This framework is designed so as to provide a practical approach that is ready to use by community managers, which is compliant with current legislation on renewable energy communities. It computes a set of optimal repartition keys, which represent the percentage of total local production given to each member – one key per metering period per member. These keys are computed based on an initial set of keys provided in the simulation, which are typically contractual i.e., agreed upon between the member and the manager the renewable energy community. This methodology is tested in a broad range of scenarios, illustrating its ability to optimise the operational costs of a renewable energy community. [less ▲]

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See detailH is for The Hangman’s Game (2007) by Karen King-Aribisala
Ledent, Bénédicte ULiege

E-print/Working paper (2020)

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Peer Reviewed
See detailLes migrations environnementales : un nouvel objet d’enseignement
Merenne-Schoumaker, Bernadette ULiege

E-print/Working paper (2020)

À partir d'idées reçues sur les migrants climatiques et environnementaux, l'autrice examine la difficulté à nommer et à quantifier ce phénomène avant de faire le point sur l'état actuel des connaissances ... [more ▼]

À partir d'idées reçues sur les migrants climatiques et environnementaux, l'autrice examine la difficulté à nommer et à quantifier ce phénomène avant de faire le point sur l'état actuel des connaissances. Elle montre ensuite comment cette question peut s'insérer dans les programmes de géographie de l'enseignement secondaire. Une place particulière est accordée aux documents, aux outils et aux démarches possibles. [less ▲]

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See detailFermeture des frontières nationales : récits en territoire transfrontalier
Caesar, Beate; Dorkel, Nicolas; Marbehant, Sylvain ULiege et al

E-print/Working paper (2020)

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See detail$\pi$ Earth: a 3.14 days Earth-sized Planet from \textit{K2}'s Kitchen served warm by the SPECULOOS Team
Niraula, Prajwal; de Wit, Julien; Rackham, Benjamin V. et al

E-print/Working paper (2020)

We report on the discovery of a transiting Earth-sized (0.95$R_\oplus$) planet around an M3.5 dwarf star at 57\,pc, EPIC~249631677. The planet has a period of $\sim$3.14 days, i.e. ${\sim}\pi$, with an ... [more ▼]

We report on the discovery of a transiting Earth-sized (0.95$R_\oplus$) planet around an M3.5 dwarf star at 57\,pc, EPIC~249631677. The planet has a period of $\sim$3.14 days, i.e. ${\sim}\pi$, with an instellation of 7.5\,S$_{\oplus}$. The detection was made using publicly available data from \textit{K2}'s Campaign 15. We observed three additional transits with SPECULOOS Southern and Northern Observatories, and a stellar spectrum from Keck/HIRES, which allowed us to validate the planetary nature of the signal. The confirmed planet is well suited for comparative terrestrial exoplanetology. While exoplanets transiting ultracool dwarfs present the best opportunity for atmospheric studies of terrestrial exoplanets with the \textit{James Webb Space Telescope}, those orbiting mid-M dwarfs within 100\,pc such as EPIC~249631677b will become increasingly accessible with the next generation of observatories (e.g., \textit{HabEx, LUVOIR, OST}). [less ▲]

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See detailEntretien avec Côme Martin-Karl : « peut-on écrire après Duras ? »
Lansmans, Alexandre ULiege

E-print/Working paper (2020)

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See detailLearning optimal environments using projected stochastic gradient ascent
Bolland, Adrien ULiege; Boukas, Ioannis ULiege; Cornet, François ULiege et al

E-print/Working paper (2020)

In this work, we generalize the direct policy search algorithms to an algorithm we call Direct Environment Search with (projected stochastic) Gradient Ascent (DESGA). The latter can be used to jointly ... [more ▼]

In this work, we generalize the direct policy search algorithms to an algorithm we call Direct Environment Search with (projected stochastic) Gradient Ascent (DESGA). The latter can be used to jointly learn a reinforcement learning (RL) environment and a policy with maximal expected return over a joint hypothesis space of environments and policies. We illustrate the performance of DESGA on two benchmarks. First, we consider a parametrized space of Mass-Spring Damper (MSD) environments. Then, we use our algorithm for optimizing the size of the components and the operation of a small-scale and autonomous energy system, i.e. a solar off-grid microgrid, composed of photovoltaic panels, batteries, etc. The results highlight the excellent performances of the DESGA algorithm. [less ▲]

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See detail新型コロナウィルス時代の情熱とは
Badir, Sémir ULiege

E-print/Working paper (2020)

Detailed reference viewed: 58 (1 ULiège)
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See detailA bio-inspired bistable recurrent cell allows for long-lasting memory
Vecoven, Nicolas ULiege; Ernst, Damien ULiege; Drion, Guillaume ULiege

E-print/Working paper (2020)

Recurrent neural networks (RNNs) provide state-of-the-art performances in a wide variety of tasks that require memory. These performances can often be achieved thanks to gated recurrent cells such as ... [more ▼]

Recurrent neural networks (RNNs) provide state-of-the-art performances in a wide variety of tasks that require memory. These performances can often be achieved thanks to gated recurrent cells such as gated recurrent units (GRU) and long short-term memory (LSTM). Standard gated cells share a layer internal state to store information at the network level, and long term memory is shaped by network-wide recurrent connection weights. Biological neurons on the other hand are capable of holding information at the cellular level for an arbitrary long amount of time through a process called bistability. Through bistability, cells can stabilize to different stable states depending on their own past state and inputs, which permits the durable storing of past information in neuron state. In this work, we take inspiration from biological neuron bistability to embed RNNs with long-lasting memory at the cellular level. This leads to the introduction of a new bistable biologically-inspired recurrent cell that is shown to strongly improves RNN performance on time-series which require very long memory, despite using only cellular connections (all recurrent connections are from neurons to themselves, i.e. a neuron state is not influenced by the state of other neurons). Furthermore, equipping this cell with recurrent neuromodulation permits to link them to standard GRU cells, taking a step towards the biological plausibility of GRU. [less ▲]

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See detailRobustness of Pisot-regular sequences
Charlier, Emilie ULiege; Cisternino, Célia ULiege; Stipulanti, Manon ULiege

E-print/Working paper (2020)

We consider numeration systems based on a d-tuple U=(U_1,...,U_d) of sequences of integers and we define (U,K)-regular sequences through K-recognizable formal series, where K is any semiring. We show that ... [more ▼]

We consider numeration systems based on a d-tuple U=(U_1,...,U_d) of sequences of integers and we define (U,K)-regular sequences through K-recognizable formal series, where K is any semiring. We show that, for any d-tuple U of Pisot numeration systems and any commutative semiring K, this definition does not depend on the greediness of the U-representations of integers. The proof is constructive and is based on the fact that the normalization is realizable by a 2d-tape finite automaton. In particular, we use an ad hoc operation mixing a 2d-tape automaton and a K-automaton in order to obtain a new K-automaton. [less ▲]

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See detailAn Artificial Intelligence Solution for Electricity Procurement in Forward Markets
Théate, Thibaut ULiege; Mathieu, Sébastien ULiege; Ernst, Damien ULiege

E-print/Working paper (2020)

Retailers and major consumers of electricity generally purchase an important percentage of their estimated electricity needs years ahead in the forward market. This long-term electricity procurement task ... [more ▼]

Retailers and major consumers of electricity generally purchase an important percentage of their estimated electricity needs years ahead in the forward market. This long-term electricity procurement task consists of determining when to buy electricity so that the resulting energy cost is minimised, and the forecast consumption is covered. In this scientific article, the focus is set on a yearly base load product from the Belgian forward market, named calendar (CAL), which is tradable up to three years ahead of the delivery period. This research paper introduces a novel algorithm providing recommendations to either buy electricity now or wait for a future opportunity based on the history of CAL prices. This algorithm relies on deep learning forecasting techniques and on an indicator quantifying the deviation from a perfectly uniform reference procurement policy. On average, the proposed approach surpasses the benchmark procurement policies considered and achieves a reduction in costs of 1.65% with respect to the perfectly uniform reference procurement policy achieving the mean electricity price. Moreover, in addition to automating the complex electricity procurement task, this algorithm demonstrates more consistent results throughout the years compared to the benchmark policies. Eventually, the generality of the solution presented makes it well suited for solving other commodity procurement problems. [less ▲]

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See detailA phylodynamic workflow to rapidly gain insights into the dispersal history and dynamics of SARS-CoV-2 lineages
Dellicour, Simon; Durkin, Keith ULiege; Hong, Samuel et al

E-print/Working paper (2020)

Since the start of the COVID-19 pandemic, an unprecedented number of genomic sequences of the causative virus (SARS-CoV-2) have been publicly released. The resulting volume of available genetic data ... [more ▼]

Since the start of the COVID-19 pandemic, an unprecedented number of genomic sequences of the causative virus (SARS-CoV-2) have been publicly released. The resulting volume of available genetic data presents a unique opportunity to gain real-time insights into the pandemic, but also a daunting computational hurdle if analysed with gold-standard phylogeographic methods. We here describe and apply an analytical pipeline that is a compromise between fast and rigorous analytical steps. As a proof of concept, we focus on Belgium, one of the countries with the highest spatial density of sequenced SARS-CoV-2 genomes. At the global scale, our analyses confirm the importance of external introduction events in establishing transmission chains in the country. At the country scale, our spatially-explicit phylogeographic analyses highlight an impact of the national lockdown of mid-March on the dispersal velocity of viral lineages. Our pipeline has the potential to be quickly applied to other countries or regions, with key benefits in complementing epidemiological analyses in assessing the impact of intervention measures or their progressive easement. [less ▲]

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See detailСтрасти в эпоху COVID
Badir, Sémir ULiege

E-print/Working paper (2020)

Detailed reference viewed: 39 (2 ULiège)
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See detailWhen and How Does Law Effectively Reduce the Practice of Female Genital Mutilation/Cutting: A crossborder Study in Burkina Faso and Mali [Policy Brief]
Wouango, Joséphine ULiege; Ostermann, L. Susan; Mwanga, Daniel

E-print/Working paper (2020)

This policy brief summarises key findings from a cross-border study of two neighbouring countries: Burkina Faso, which has a strong FGM/C law, and Mali, which has no specific FGM/C law (Wouango, Ostermann ... [more ▼]

This policy brief summarises key findings from a cross-border study of two neighbouring countries: Burkina Faso, which has a strong FGM/C law, and Mali, which has no specific FGM/C law (Wouango, Ostermann, and Mwanga 2020). The aim of the cross-border study was to explore and compare attitudes and tendencies towards obeying the law and continuing FGM/C practises and to understand the effectiveness of criminal law in combatting FGM/C in both countries. [less ▲]

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See detailDans quelles conditions la loi est-elle efficace pour réduire la pratique des mutilations génitales féminines/excision: Une étude transfrontalière au Burkina Faso et au Mali [Policy Brief]
Wouango, Joséphine ULiege; Ostermann, Susan; Mwanga, Daniel

E-print/Working paper (2020)

Cette note de synthèse résume les principales conclusions d'une étude transfrontalière portant sur deux pays voisins : le Burkina Faso, qui dispose d'une loi forte sur les MGF/E, et le Mali, qui n'a pas ... [more ▼]

Cette note de synthèse résume les principales conclusions d'une étude transfrontalière portant sur deux pays voisins : le Burkina Faso, qui dispose d'une loi forte sur les MGF/E, et le Mali, qui n'a pas de loi spécifique sur les MGF/E (Wouango, Ostermann, et Mwanga 2020). Les objectifs de l'étude transfrontalière étaient d'explorer et de comparer les attitudes et les tendances en matière de respect de la loi et de poursuite de la pratique des MGF/E, et de comprendre l'efficacité du droit pénal dans la lutte contre les MGF/E dans les deux pays. [less ▲]

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See detailÉvaluer les effets des différentes mesures de lutte contre le Covid-19, mission impossible?
Paul, Elisabeth ULiege; Ridde, Valéry

E-print/Working paper (2020)

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See detailLong Way to Universal Health Coverage (UHC): Are Policy Dialogue Processes Appropriate to Negotiate Trade-Offs in Africa? The Cases of Benin and Senegal
Paul, Elisabeth ULiege; Fecher-Bourgeois, Fabienne ULiege; Deville, Céline ULiege et al

E-print/Working paper (2020)

The numerous stakeholders involved in the development of universal health coverage (UHC) policies are likely to have diverging interests about which dimensions to prioritize, hence the importance of ... [more ▼]

The numerous stakeholders involved in the development of universal health coverage (UHC) policies are likely to have diverging interests about which dimensions to prioritize, hence the importance of ensuring an effective and transparent policy dialogue. This paper aims to investigate whether or not UHC policy dialogue processes are functioning well in Benin and Senegal. Based on a literature review, we have identified a number of characteristics guaranteeing the quality of policy dialogue processes, which we have integrated into an analytical grid. The quality criteria identified were classified along four dimensions: stakeholder participation, dialogue/negotiation process, quality of situation analysis and decision criteria, and results from the negotiation process. Based on data collected through documentary review, interviews, an electronic survey and the authors’ own experience, we applied that analytical grid to the cases of Benin and Senegal. In both countries, the policy dialogue processes are largely imperfect in terms of many of the quality criteria identified. Decisions were made under strong political leadership, ensuring government coordination and ownership, and strong emphasis has been put on expanding financial risk protection. Yet, both countries perform poorly in a number of dimensions, especially with regards to conflicts of interest, transparency and accountability. None of them has really institutionalized a UHC policy dialogue process, and the UHC policymaking processes have actually bypassed existing health sector coordination mechanisms. The two countries perform well regarding the quality of situation analysis. A small (in the case of Benin) or broader (in the case of Senegal) governmental coalition managed to impose its views, given insufficient stakeholder participation. Policy networks were particularly influential in Senegal. Overall, there are important gaps that reduce the quality of UHC policy dialogue processes, hence explaining the weaknesses in their results in terms of transparency and accountability. Our analytical framework enables us to identify rooms for improvement with regard to country-led negotiation processes relating to UHC. [less ▲]

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See detailHigh Order Relaxation Methods for Co-simulation of Finite Element and Circuit Solvers
Nshimiyimana, Jean de Dieu ULiege; Plumier, Frédéric; Ndagije, Charles et al

E-print/Working paper (2020)

Coupled problems result in very stiff problems whose char- acteristic parameters differ with several orders in magni- tude. For such complex problems, solving them monolith- ically becomes prohibitive ... [more ▼]

Coupled problems result in very stiff problems whose char- acteristic parameters differ with several orders in magni- tude. For such complex problems, solving them monolith- ically becomes prohibitive. Since nowadays there are op- timized solvers for particular problems, solving uncoupled problems becomes easy since each can be solved indepen- dently with its dedicated optimized tools. Therefore the co-simulation of the sub-problems solvers is encouraged. The design of the transmission coupling conditions between solvers plays a fundamental role. The current paper applies the waveform relaxation methods for co-simulation of the finite element and circuit solvers, investigate the contribu- tion of higher order integration methods and also consid- ers the the theoretical modelling of a boost converter. The method is illustrated on a coupled finite element inductor and a boost converter and focuses on the comparison of the transmission coupling conditions based on the waveform iteration numbers between the two sub-solvers. We demon- strate that for lightly coupled systems the dynamic itera- tions between the sub-solvers depends much on the inter- nal integrators in individual sub-solvers whereas for tightly coupled systems it depends also to the kind of transmission coupling conditions. [less ▲]

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See detailLuciano Curreri e la letteratura
Curreri, Luciano ULiege

E-print/Working paper (2020)

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See detailThe CARMENES search for exoplanets around M dwarfs. Two planets on the opposite sides of the radius gap transiting the nearby M dwarf LP 729-54
Nowak, G.; Luque, R.; Parviainen, H. et al

E-print/Working paper (2020)

We present the discovery and characterisation of two transiting planets observed by the Transiting Exoplanet Survey Satellite (TESS) orbiting the nearby (d ~ 22 pc), bright (J ~ 9 mag) M3.5 dwarf LP 729 ... [more ▼]

We present the discovery and characterisation of two transiting planets observed by the Transiting Exoplanet Survey Satellite (TESS) orbiting the nearby (d ~ 22 pc), bright (J ~ 9 mag) M3.5 dwarf LP 729-54 (TOI-732). We confirm both planets and their association with LP 729-54 via ground-based photometry and determine their masses using precise radial velocities measured with the CARMENES spectrograph. Precise stellar parameters determined from CARMENES high resolution spectra confirm that LP 729-54 is a mid-M dwarf with an effective temperature of T_eff = 3360 +\- 51 K, a surface gravity of log(g) = 4.81 +/- 0.04 (cgs), and an iron abundance of [Fe/H] = 0.09 +/- 0.16 dex, with an inferred mass of M_star = 0.379 +/- 0.016 M_sun and a radius of R_star = 0.382 +/- 0.012 R_sun. The ultra-short period planet LP 729-54 b (P_b = 0.77 d) with a radius of 1.35^{+0.06}_{-0.06} R_earth, a mass of 2.34^{+0.24}_{-0.23} M_earth, and a bulk density of 5.24^{+0.94}_{-0.81} g cm^{-3} joins the population of Earth-size planets with rocky, terrestrial composition. The outer planet, LP 729-54 c, with an orbital period of 12.25 d, radius of 2.42^{+0.10}_{-0.10} R_earth, mass of 6.29^{+0.63}_{-0.61} M_earth, and mean density of 2.45^{+0.44}_{-0.37} g cm^{-3} belongs to the population of dense sub-Neptunes. With the two planets located on opposite sides of the radius gap, this planetary system is an excellent target for testing planetary formation, evolution and atmospheric models. In particular, LP 729-54 c is an ideal object for atmospheric studies with the James Webb Space Telescope. [less ▲]

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See detailThree Short Period Jupiters from TESS
Nielsen, L. D.; Brahm, R.; Bouchy, F. et al

E-print/Working paper (2020)

We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period ... [more ▼]

We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period Jupiter orbiting a bright (V=11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 +/- 0.078 Mjup planet in a grazing transit configuration with impact parameter b = 1.17 +0.10/-0.08. As a result the radius is poorly constrained, 2.03 +0.61/-0.49 Rjup. We perform a full phase-curve analysis of the TESS data and detect both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass 1.18 +/- 0.13 Mjup and radius 1.29 +/- 0.02 Rjup. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V=12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V=12.4 G-type star. It has a mass of 0.79 +/- 0.06 Mjup and radius 1.09 +0.08/-0.05 Rjup. Despite having the longest orbital period (P=2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with Fe/H ranging from 0.18 - 0.24. [less ▲]

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See detailSPHERE+: Imaging young Jupiters down to the snowline
Boccaletti, A.; Chauvin, G.; Mouillet, D. et al

E-print/Working paper (2020)

SPHERE (Beuzit et al,. 2019) has now been in operation at the VLT for more than 5 years, demonstrating a high level of performance. SPHERE has produced outstanding results using a variety of operating ... [more ▼]

SPHERE (Beuzit et al,. 2019) has now been in operation at the VLT for more than 5 years, demonstrating a high level of performance. SPHERE has produced outstanding results using a variety of operating modes, primarily in the field of direct imaging of exoplanetary systems, focusing on exoplanets as point sources and circumstellar disks as extended objects. The achievements obtained thus far with SPHERE (~200 refereed publications) in different areas (exoplanets, disks, solar system, stellar physics...) have motivated a large consortium to propose an even more ambitious set of science cases, and its corresponding technical implementation in the form of an upgrade. The SPHERE+ project capitalizes on the expertise and lessons learned from SPHERE to push high contrast imaging performance to its limits on the VLT 8m-telescope. The scientific program of SPHERE+ described in this document will open a new and compelling scientific window for the upcoming decade in strong synergy with ground-based facilities (VLT/I, ELT, ALMA, and SKA) and space missions (Gaia, JWST, PLATO and WFIRST). While SPHERE has sampled the outer parts of planetary systems beyond a few tens of AU, SPHERE+ will dig into the inner regions around stars to reveal and characterize by mean of spectroscopy the giant planet population down to the snow line. Building on SPHERE's scientific heritage and resounding success, SPHERE+ will be a dedicated survey instrument which will strengthen the leadership of ESO and the European community in the very competitive field of direct imaging of exoplanetary systems. With enhanced capabilities, it will enable an even broader diversity of science cases including the study of the solar system, the birth and death of stars and the exploration of the inner regions of active galactic nuclei. [less ▲]

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See detailNote relative à l’Agenda urbain de l’UE
Lejeune, Zoé ULiege; Claeys, Dorian ULiege

E-print/Working paper (2020)

Cette note explique le processus de l'Agenda urbain de l'UE pour toute personne ou autorité intéressée de mieux comprendre la dynamique.

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See detailElectron-lattice interplays in LaMnO 3 from canonical Jahn-Teller distortion notations
Schmitt, Michaël ULiege; Zhang, Yajun; Mercy, Alain ULiege et al

E-print/Working paper (2020)

Detailed reference viewed: 42 (18 ULiège)
See detailSeraing, ville post-industrielle en pleine reconversion, se penche sur le défi de la réactivation de son bâti vacant
Lejeune, Zoé ULiege

E-print/Working paper (2020)

Interview avec la ville de Seraing dans le cadre de sa participation au réseau URBACT "AltBau" qui travaille à une stratégie de réactivation des immeubles inoccupés.

Detailed reference viewed: 36 (1 ULiège)
See detailImmigration, Welfare and Inequality: How Much Does the Labor Market Specification Matter?
Docquier, Frédéric; Ikhenaode, Bright Isaac; Scheewel, Hendrik ULiege

E-print/Working paper (2020)

Macroeconomic models are increasingly used to quantify the welfare and inequality effects of immigration in the OECD countries. Existing studies differ in the way they formalize the labor market responses ... [more ▼]

Macroeconomic models are increasingly used to quantify the welfare and inequality effects of immigration in the OECD countries. Existing studies differ in the way they formalize the labor market responses for immigrants and natives, which in turn govern the strength of the other transmission channels (e.g., public finances, price index, or total factor productivity). In this paper, we build a general equilibrium model that allows to gauge the role of the labor market specification. We parameterize the model for 20 selected OECD member states and compare several specifications involving different assumptions concerning labor supply decisions, unemployment rates and wage formation, as well as different calibration strategies. Endogenizing unemployment and participation generates slightly more optimistic results. However, these labor market mechanisms do not reverse the findings of models based on simpler assumptions and have little effects on cross-country differences in responses to immigration. The labor market specification is less important than the calibration of the elasticity of substitution between immigrants and natives. [less ▲]

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See detailLe pouvoir poétique des images de cinéma
Badir, Sémir ULiege

E-print/Working paper (2020)

Detailed reference viewed: 45 (4 ULiège)
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See detailUn savant dans l'Ouest : Jean-Charles Houzeau de Lehaie ou l'évolutionnisme nomade
Royen, Virgile ULiege

E-print/Working paper (2020)

Ce récit raconte l'exil de Jean-Charles Houzeau de Lehaie, astronome belge, dans le Nouveau Monde. Son esprit indépendant et son opposition à l'esclavage dans le contexte de la Guerre de Sécession le ... [more ▼]

Ce récit raconte l'exil de Jean-Charles Houzeau de Lehaie, astronome belge, dans le Nouveau Monde. Son esprit indépendant et son opposition à l'esclavage dans le contexte de la Guerre de Sécession le conduisirent régulièrement à arpenter ou vivre en terres sauvages. Au cours de ces pérégrinations exotiques, Houzeau réalisa de nombreuses observations sur la faune, qu'il compila en deux épais volumes, les Études sur les Facultés mentales des animaux comparées à celles de l’Homme. Un livre qui n'ambitionnait pas moins de devancer Darwin lui-même... [less ▲]

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See detailBlanche est la mort
Frankignoulle, Pierre ULiege

E-print/Working paper (2020)

Une nouvelle de 17 pages

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Peer Reviewed
See detailInterstellar comet 2I/Borisov as seen by MUSE: C2, NH2 and red CN detections
Bannister, Michele T.; Opitom, Cyrielle; Fitzsimmons, Alan et al

E-print/Working paper (2020)

We report the clear detection of C$_2$ and of abundant NH$_2$ in the first prominently active interstellar comet, 2I/Borisov. We observed 2I on three nights in November 2019 at optical wavelengths 4800 ... [more ▼]

We report the clear detection of C$_2$ and of abundant NH$_2$ in the first prominently active interstellar comet, 2I/Borisov. We observed 2I on three nights in November 2019 at optical wavelengths 4800--9300 Åwith the Multi-Unit Spectroscopic Explorer (MUSE) integral-field spectrograph on the ESO/Very Large Telescope. These data, together with observations close in time from both 0.6-m TRAPPIST telescopes, provide constraints on the production rates of species of gas in 2I's coma. From the MUSE detection on all epochs of several bands of the optical emission of the C$_2$ Swan system, a rich emission spectrum of NH$_2$ with many highly visible bands, and the red (1-0) bandhead of CN, together with violet CN detections by TRAPPIST, we infer production rates of $Q$(C$_2$) = $1.1\times10^{24}$ mol s$^{-1}$, $Q$(NH$_2$) = $4.8\times10^{24}$ mol s$^{-1}$ and $Q$(CN) = $(1.8\pm0.2)\times 10^{24}$ mol s$^{-1}$. In late November at 2.03~au, 2I had a production ratio of C$_2$/CN$=0.61$, only barely carbon-chain depleted, in contrast to earlier reports measured further from the Sun of strong carbon-chain depletion. Thus, 2I has shown evolution in its C$_2$ production rate: a parent molecule reservoir has started sublimating. At $Q$(NH$_2$)/$Q$(CN) = 2.7, this second interstellar object is enriched in NH$_2$, relative to the known Solar System sample. [less ▲]

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See detailUn risque d'instrumentalisation de l'histoire
Franck, Thomas ULiege

E-print/Working paper (2020)

Detailed reference viewed: 54 (6 ULiège)
See detailAlzheimer s disease genetic risk and sleep phenotypes: association with more slow-waves and daytime sleepiness
Muto, Vincenzo ULiege; Koshmanova, Ekaterina ULiege; Ghaemmaghami, Pouya  et al

E-print/Working paper (2020)

Detailed reference viewed: 60 (15 ULiège)
Peer Reviewed
See detailGenebank Platform: GreenPass puts germplasm distribution in the fast lane
Massart, Sébastien ULiege; Major, Michael; Kumar, Lava

E-print/Working paper (2020)

Detailed reference viewed: 23 (1 ULiège)
Peer Reviewed
See detailNotice VANDERRYDT Hippolyte
Georges, Martin ULiege

E-print/Working paper (2020)

Biographie et bibliographie de Hippolyte Vanderrydt (1857 – 1929). Ingénieur, enseignant de l'ULB et de l'Université Nouvelle, militant socialiste (POB), premier traducteur en langue française du livre II ... [more ▼]

Biographie et bibliographie de Hippolyte Vanderrydt (1857 – 1929). Ingénieur, enseignant de l'ULB et de l'Université Nouvelle, militant socialiste (POB), premier traducteur en langue française du livre II (1900) et III (1901-1902) du Capital de Karl Marx avec Julian Borchardt, corédacteur de la Charte de Quaregnon, collaborateur des journaux Le Peuple et L’Avenir social sous le pseudonyme de « LUX », enseignant à la Centrale d’éducation ouvrière et à l’École ouvrière supérieure. [less ▲]

Detailed reference viewed: 73 (4 ULiège)
See detailIncreased cortical excitability and reduced brain response propagation during attentional lapses
Cardone, Paolo ULiege; Van Egroo, Maxime ULiege; Chylinski, Daphné ULiege et al

E-print/Working paper (2020)

Modern lifestyle curtails sleep and increases nighttime work and leisure activities. This has a deleterious impact on vigilance and attention, exacerbating chances of committing attentional lapses, with ... [more ▼]

Modern lifestyle curtails sleep and increases nighttime work and leisure activities. This has a deleterious impact on vigilance and attention, exacerbating chances of committing attentional lapses, with potential dramatic outcomes. A full characterization of the brain mechanisms associated with lapses is still lacking. Here, we investigated the brain signature of attentional lapses and assessed whether cortical excitability and brain response propagation were modified during lapses and whether these modifications changed with aging. We compared electroencephalogram (EEG) responses to transcranial magnetic stimulation (TMS) during lapse and no-lapse periods while performing a continuous attentional/vigilance task at night, after usual bedtime. Data were collected in healthy younger (N=12; 18-30 y) and older individuals (N=12; 50- 70 y) of both sexes. Amplitude and slope of the first component of the TMS-Evoked Potential (TEP) and Response Scattering (ReSc) were used to assess cortical excitability and brain response propagation, respectively. In line with our predictions, TEP during lapses was characterized by larger amplitude and slope. We further found that ReSc over the cortical surface was lower during lapses. Importantly, cortical excitability increase and response propagation decrease during lapse did not significantly differ between age groups. These results demonstrate that attentional lapses are associated with transient increase of excitability, and decrease in response propagation and effective connectivity. This pattern is similar to what is observed during sleep, suggesting that lapses reflect a sleep-like phenomenon. These findings could contribute to develop models aimed to predicting and preventing lapses in real life situations. [less ▲]

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See detailMental resilience in the Corona lockdown: First empirical insights from Europe
Veer, Ilya; Riepenhausen, Antje; Zerban, Matthias et al

E-print/Working paper (2020)

Background: The current Corona pandemic is not only a threat to physical health. First data from China and Europe indicate that symptoms of anxiety and depression and perceptions of stress rise ... [more ▼]

Background: The current Corona pandemic is not only a threat to physical health. First data from China and Europe indicate that symptoms of anxiety and depression and perceptions of stress rise significantly as a consequence of the pandemic. There are also anecdotal reports of increased domestic violence, divorce, and suicide rates. Hence, the Corona crisis is also a mental health crisis. There is urgent need for knowledge about factors that can protect mental health (resilience factors) in this world-wide crisis, which is different in nature from other crises that have so far been studied in resilience research. Methods: Potential resilience factors, exposure to Corona-specific and general stressors, as well as internalizing symptoms were assessed online in N=5000 adult Europeans. Resilience, as an outcome, was conceptualized as good mental health despite stressor exposure and measured as the inverse residual between actual and predicted symptom total score. Preregistered hypotheses (osf.io/r6btn) were tested with multiple regression models and mediation analyses. Results: Results confirmed our primary hypothesis that positive appraisal style (PAS) is positively associated with resilience(p<0.001). The resilience factor PAS also mediated the positive association between perceived social support (PSS) and resilience (p<0.001). In comparison with other resilience factors, positive appraisal specifically of the consequences of the Corona crisis was the single strongest factor. Conclusions: This research identifies modifiable protective factors that can be targeted by public mental health efforts. Future work will have to identify potential group differences in the effectiveness of these resilience factors, for improved prevention planning [less ▲]

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See detailFighting against homesickness
Lara Guerrero, Larisa Viridiana ULiege

E-print/Working paper (2020)

Detailed reference viewed: 16 (2 ULiège)
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See detailAge dating of an early Milky Way merger via asteroseismology of the naked-eye star ν Indi
Chaplin, W. J.; Serenelli, A. M.; Miglio, A. et al

E-print/Working paper (2020)

Over the course of its history, the Milky Way has ingested multiple smaller satellite galaxies1. Although these accreted stellar populations can be forensically identified as kinematically distinct ... [more ▼]

Over the course of its history, the Milky Way has ingested multiple smaller satellite galaxies1. Although these accreted stellar populations can be forensically identified as kinematically distinct structures within the Galaxy, it is difficult in general to date precisely the age at which any one merger occurred. Recent results have revealed a population of stars that were accreted via the collision of a dwarf galaxy, called Gaia–Enceladus1, leading to substantial pollution of the chemical and dynamical properties of the Milky Way. Here we identify the very bright, naked-eye star ν Indi as an indicator of the age of the early in situ population of the Galaxy. We combine asteroseismic, spectroscopic, astrometric and kinematic observations to show that this metal-poor, alpha-element-rich star was an indigenous member of the halo, and we measure its age to be 11.0 ± 0.7 (stat) ± 0.8 (sys) billion years. The star bears hallmarks consistent with having been kinematically heated by the Gaia–Enceladus collision. Its age implies that the earliest the merger could have begun was 11.6 and 13.2 billion years ago, at 68% and 95% confidence, respectively. Computations based on hierarchical cosmological models slightly reduce the above limits. © 2020, The Author(s), under exclusive licence to Springer Nature Limited. [less ▲]

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See detailPerturbations in dynamical models of whole-brain activity dissociate between the level and stability of consciousness
Sanz Perl; Pallavicini, Carla; Pérez Ipiña, Ignacio et al

E-print/Working paper (2020)

Detailed reference viewed: 27 (1 ULiège)
See detailFigures du retraducteur
Belleflamme, Clémence ULiege

E-print/Working paper (2019)

Compte-rendu de la journée d'étude "Figures du retraducteur" organisée par le CIRTI le 11 décembre 2019 à l'Université de Liège.

Detailed reference viewed: 23 (1 ULiège)
See detailDe retraducción a recepción...
Belleflamme, Clémence ULiege

E-print/Working paper (2019)

Informe del coloquio “Figures du retraducteur” (Figuras del retraductor), organizado por el Centro Interdisciplinar de Investigación en Traducción e Interpretación (CIRTI), que tuvo lugar el 11 de ... [more ▼]

Informe del coloquio “Figures du retraducteur” (Figuras del retraductor), organizado por el Centro Interdisciplinar de Investigación en Traducción e Interpretación (CIRTI), que tuvo lugar el 11 de diciembre de 2019 en la Universidad de Lieja. En él se dieron cita traductores y traductólogos para reflexionar sobre la retraducción —entendida como una nueva traducción de un texto que ya se ha traducido a la misma lengua con anterioridad— y, más particularmente, sobre las distintas facetas de la tarea del retraductor. Se pasa revista a las distintas ponencias, con un enfoque en el vínculo que se puede establecer entre retraducción y recepción. [less ▲]

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See detailMCMCI: A code to fully characterise an exoplanetary system
Bonfanti, Andrea ULiege; Gillon, Michaël ULiege

E-print/Working paper (2019)

Useful information can be retrieved by analysing the transit light curve of a planet-hosting star or induced radial velocity oscillations. However, inferring the physical parameters of the planet, such as ... [more ▼]

Useful information can be retrieved by analysing the transit light curve of a planet-hosting star or induced radial velocity oscillations. However, inferring the physical parameters of the planet, such as mass, size, and semi-major axis, requires preliminary knowledge of some parameters of the host star, especially its mass or radius, which are generally inferred through theoretical evolutionary models. We seek to present and test a whole algorithm devoted to the complete characterisation of an exoplanetary system thanks to the global analysis of photometric or radial velocity time series combined with observational stellar parameters derived either from spectroscopy or photometry. We developed an integrated tool called MCMCI. This tool combines the Markov chain Monte Carlo (MCMC) approach of analysing photometric or radial velocity time series with a proper interpolation within stellar evolutionary isochrones and tracks, known as isochrone placement, to be performed at each chain step, to retrieve stellar theoretical parameters such as age, mass, and radius. We tested the MCMCI on the HD 219134 multi-planetary system hosting two transiting rocky super Earths and on WASP-4, which hosts a bloated hot Jupiter. Even considering different input approaches, a final convergence was reached within the code, we found good agreement with the results already stated in the literature and we obtained more precise output parameters, especially concerning planetary masses. The MCMCI tool offers the opportunity to perform an integrated analysis of an exoplanetary system without splitting it into the preliminary stellar characterisation through theoretical models. Rather this approach favours a close interaction between light curve analysis and isochrones, so that the parameters recovered at each step of the MCMC enter as inputs for purposes of isochrone placement. [less ▲]

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See detailUn croyant grincheux. Recension de Romans et nouvelles de J.-K. Huysmans
Lansmans, Alexandre ULiege

E-print/Working paper (2019)

Detailed reference viewed: 18 (0 ULiège)
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See detailEen gedicht belicht. Over De moordenaars van Paul van Ostaijen
Spinoy, Erik ULiege

E-print/Working paper (2019)

This text offers a rereading of the well-known poem 'De moordenaars' by Flemish expressionist poet Paul van Ostaijen in light of the numerous references to contemporary popular culture that can be found ... [more ▼]

This text offers a rereading of the well-known poem 'De moordenaars' by Flemish expressionist poet Paul van Ostaijen in light of the numerous references to contemporary popular culture that can be found in the text. [less ▲]

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Peer Reviewed
See detailImplementation of the EPPO in Belgium: Making the Best of a (Politically) Forced Marriage?
Verbruggen, Frank; Franssen, Vanessa ULiege; Claes, Ana Laura et al

E-print/Working paper (2019)

Detailed reference viewed: 28 (3 ULiège)
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Peer Reviewed
See detailDetection and Attribution of Wildfire Pollution in the Arctic and Northern Mid-latitudes using a Network of FTIR Spectrometers and GEOS-Chem
Lutsch, Erik; Strong, Kimberly; Jones, Dylan B. A. et al

E-print/Working paper (2019)

We present a multi-year time series of column abundances of carbon monoxide (CO), hydrogen cyanide (HCN), and ethane (C2H6) measured using Fourier transform infrared (FTIR) spectrometers at ten sites ... [more ▼]

We present a multi-year time series of column abundances of carbon monoxide (CO), hydrogen cyanide (HCN), and ethane (C2H6) measured using Fourier transform infrared (FTIR) spectrometers at ten sites affiliated with the Network for Detection of Atmospheric Composition Change (NDACC). Six are high-latitude sites: Eureka, Ny-Alesund, Thule, Kiruna, Poker Flat, and St. Petersburg , and four are mid-latitude sites: Zugspitze, Jungfraujoch, Toronto, and Rikubetsu. For each site, the inter-annual trends and seasonal variabilities of the CO time series are accounted for, allowing ambient concentrations to be determined. Enhancements above ambient levels were used to identify possible wildfire pollution events. Since the abundance of each trace gas emitted in a wildfire event is specific to the type of vegetation burned and the burning phase, correlations of CO to the long-lived wildfire tracers HCN and C2H6 allow for further confirmation of the detection of wildfire pollution, while complementary measurements of aerosol optical depth from nearby AERONET sites confirm the presence of wildfire smoke. A GEOS-Chem tagged CO simulation with Global Fire Assimilation System (GFAS) biomass burning emissions was used to determine the source attribution of CO concentrations at each site from 2003–2018. The influence of the various wildfire sources is found to differ between sites while North American and Asian boreal wildfires fires were found to be the greatest contributors to episodic CO enhancements in the summertime at all sites. [less ▲]

Detailed reference viewed: 62 (4 ULiège)
See detailThe Geography of Climate Migration
Docquier, Frédéric; Burzyński, Michał; Scheewel, Hendrik ULiege

E-print/Working paper (2019)

This paper investigates the long-term effects of climate change on the size, skill composition and geography of labor migration. Our world economy model distinguishes between many spatial units and fully ... [more ▼]

This paper investigates the long-term effects of climate change on the size, skill composition and geography of labor migration. Our world economy model distinguishes between many spatial units and fully endogenizes the dyadic structure of migration. The model is calibrated to match international and internal mobility data by education level from the last 30 years, and is then simulated under climate change variants. Depending on the climate scenario, we predict mobility responses in the range of 100 to 230 million adult people over the course of the 21st century. Most of these movements are local or inter-regional. South-South international migration responses are negligible, while the South-North migration response is of the ”brain drain” type and induces a permanent increase in the stock of foreigners in the OECD countries in the range of 5 to 10% only. Changes in the sea level mainly translate into local movements. On the contrary, inter-regional and international movements are sensitive to temperature-related changes in productivity. We finally show that relaxing international migration restrictions may exacerbate the poverty effect of climate change if policymakers are unable to select/screen individuals in extreme poverty. [less ▲]

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See detailTrapping of electrons around nanoscale metallic wires embedded in a semiconductor medium
Huynh, Chi Cuong ULiege; Evrard, Roger ULiege; Nguyen, Ngoc Duy ULiege

E-print/Working paper (2019)

We predict that conduction electrons in a semiconductor film containing a centered square array of metal nanowires normal to its plane are bound in quantum states around the central wires, if a positive ... [more ▼]

We predict that conduction electrons in a semiconductor film containing a centered square array of metal nanowires normal to its plane are bound in quantum states around the central wires, if a positive bias voltage is applied between the wires at the square vertices and these latter. We obtain and discuss the eigenenergies and eigenfunctions of two models with different dimensions. The results show that the eigenstates can be grouped into different shells. The energy differences between the shells is typically a few tens of meV, which corresponds to frequencies of emitted or absorbed photons in a range of 3 THz to 20 THz approximately. These energy differences strongly depend on the bias voltage. We calculate the linear response of individual electrons on the ground level of our models to large-wavelength electromagnetic waves whose electric field is in the plane of the semiconductor film. The computed oscillator strengths are dominated by the transitions to the states in each shell whose wave function has a single radial node line normal to the wave electric field. We include the effect of the image charge induced on the central metal wires and show that it modifies the oscillator strengths so that their sum deviates from the value given by the Thomas-Reiche-Kuhn rule. We report the linear response, or polarizability, versus photon energy, of the studied models and their absorption spectra. These latter show well-defined peaks as expected from the study of the oscillator strengths. We show that the position of these absorption peaks is strongly dependent on the bias voltage so that the frequency of photon absorption or emission in the systems described here is easily tunable. This makes them good candidates for the development of novel infrared devices. [less ▲]

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See detailDie französisch-belgischen Beziehungen
Lanneau, Catherine ULiege

E-print/Working paper (2019)

Detailed reference viewed: 34 (3 ULiège)
Full Text
See detailA super-solar metallicity atmosphere for WASP-127b revealed by transmission spectroscopy from HST and Spitzer
Spake, Jessica J.; Sing, David K.; Wakeford, Hannah R. et al

E-print/Working paper (2019)

The chemical abundances of exoplanet atmospheres may provide valuable information about the bulk compositions, formation pathways, and evolutionary histories of planets. Exoplanets which have large ... [more ▼]

The chemical abundances of exoplanet atmospheres may provide valuable information about the bulk compositions, formation pathways, and evolutionary histories of planets. Exoplanets which have large, relatively cloud-free atmospheres, and which orbit bright stars provide the best opportunities for accurate abundance measurements. For this reason, we measured the transmission spectrum of the bright (V~10.2), large (1.37RJ), sub-Saturn mass (0.19MJ) exoplanet WASP-127b across the near-UV to near-infrared wavelength range (0.3 - 5 microns), using the Hubble and Spitzer Space Telescopes. Our results show a feature-rich transmission spectrum, with absorption from Na, H2O, and CO2, as well as wavelength-dependent scattering from small-particle condensates, and a grey absorber which somewhat mutes the molecular absorption features. We ran two types of atmospheric retrieval models: one enforcing chemical equilibrium, and the other which fit the abundances freely. Our retrieved abundances at chemical equilibrium for Na, O and C are all super-solar, with abundances relative to solar values of 51+30-29, 23+15-9, and 33+43-25 respectively. Despite giving conflicting C/O ratios, both retrievals gave super-solar CO2 volume mixing ratios, which adds to the likelihood that WASP-127b's bulk metallicity is super-solar, since CO2 abundance is highly sensitive to atmospheric metallicity. In the future, spectroscopy with JWST will be able to constrain WASP-127b's C/O ratio, and may reveal the formation history of this metal-enriched, highly observable exoplanet. [less ▲]

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See detailStatistical analysis of modulated codes for robot positioning -- Application to BeAMS
Pierlot, Vincent ULiege; Van Droogenbroeck, Marc ULiege

E-print/Working paper (2019)

Positioning is a fundamental issue for mobile robots. Therefore, a performance analysis is suitable to determine the behavior of a system, and to optimize its working. Unfortunately, some systems are only ... [more ▼]

Positioning is a fundamental issue for mobile robots. Therefore, a performance analysis is suitable to determine the behavior of a system, and to optimize its working. Unfortunately, some systems are only evaluated experimentally, which makes the performance analysis and design decisions very unclear. In [4], we have proposed a new angle measurement system, named BeAMS, that is the key element of an algorithm for mobile robot positioning. BeAMS introduces a new mechanism to measure angles: it detects a beacon when it enters and leaves an angular window. A theoretical framework for a thorough performance analysis of BeAMS has been provided to establish the upper bound of the variance, and to validate this bound through experiments and simulations. It has been shown that the estimator derived from the center of this angular window provides an unbiased estimate of the beacon angle. This document complements our paper by going into further details related to the code statistics of modulated signals in general, with an emphasis on BeAMS. In particular, the probability density function of the measured angle has been previously established with the assumption that there is no correlation between the times a beacon enters the angular window or leaves it. This assumption is questionable and, in this document, we reconsider this assumption and establish the exact probability density function of the angle estimated by BeAMS (without this assumption). The conclusion of this study is that the real variance of the estimator provided by BeAMS was slightly underestimated in our previous work. In addition to this speci c result, we also provide a new and extensive theoretical approach that can be used to analyze the statistics of any angle measurement method with beacons whose signal has been modulated. To summarize, this technical document has four purposes: (1) to establish the exact probability density function of the angle estimator of BeAMS, (2) to calculate a practical upper bound of the variance of this estimator, which is of practical interest for calibration and tracking (see Table 1, on page 13, for a summary), (3) to present a new theoretical approach to evaluate the performance of systems that use modulated (coded) signals, and (4) to show how the variance evolves exactly as a function of the angular window (while re- maining below the upper bound). [less ▲]

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See detailOn the dimension group of unimodular S-adic subshifts
Berthé, Valérie; Cecchi Bernales, Paulina; Durand, Fabien et al

E-print/Working paper (2019)

Detailed reference viewed: 24 (1 ULiège)
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See detailThe European regional order in the Western Balkans facing the disrupting role of middle and great emerging powers
Lika, Liridon ULiege

E-print/Working paper (2019)

This EUCROSS Working paper analyses the European regional order in the Western Balkans which is more and more challenged by the projection of the emerging powers in this region. In other words, it aims to ... [more ▼]

This EUCROSS Working paper analyses the European regional order in the Western Balkans which is more and more challenged by the projection of the emerging powers in this region. In other words, it aims to analyses the new international balance of power in the context of the diffusion of global power in a changing world order. The paper is divided into three parts. The first part explains particularly the context of the penetration of emerging powers into a European space as is the region of the Western Balkans. The second focus on their objectives and strategies to challenge the European regional order. Finally, the third studies the European response in order to remain the most visible player in the Western Balkans. [less ▲]

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See detailThe Potential of Exozodiacal Disks Observations with the WFIRST Coronagraph Instrument
Mennesson, B.; Bailey, V.; Kasdin, J. et al

E-print/Working paper (2019)

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) will be the first high-performance stellar coronagraph using active wavefront control for deep starlight suppression in space ... [more ▼]

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) will be the first high-performance stellar coronagraph using active wavefront control for deep starlight suppression in space, providing unprecedented levels of contrast, spatial resolution, and sensitivity for astronomical observations in the optical. One science case enabled by the CGI will be taking images and(R~50)spectra of faint interplanetary dust structures present in the habitable zone of nearby sunlike stars (~10 pc) and within the snow-line of more distant ones(~20pc), down to dust density levels commensurate with that of the solar system zodiacal cloud. Reaching contrast levels below~10-7 for the first time, CGI will cross an important threshold in debris disks physics, accessing disks with low enough optical depths that their structure is dominated by transport phenomena than collisions. Hence, CGI results will be crucial for determining how exozodiacal dust grains are produced and transported in low-density disks around mature stars. Additionally, CGI will be able to measure the brightness level and constrain the degree of asymmetry of exozodiacal clouds around individual nearby sunlike stars in the optical, at the ~10x solar zodiacal emission level. This information will be extremely valuable for optimizing the observational strategy of possible future exo-Earth direct imaging missions, especially those planning to operate at optical wavelengths, such as Habitable Exoplanet Observatory (HabEx) and the Large Ultraviolet/Optical/Infrared Surveyor (LUVOIR). <P /> [less ▲]

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See detailLes nouvelles routes de la soie: Projet sino-centré ou projet d'hégémonie
Riga, Dealan ULiege

E-print/Working paper (2019)

Entretien avec Thierry Kellner, docteur en relations internationales

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See detailÀ la conquête de la politique scientifique : Duel Rue de la Science
Royen, Virgile ULiege

E-print/Working paper (2019)

Ce récit est le second de deux articles portant sur la naissance de la politique scientifique en Belgique. Il étudie la mutation du financement et de l'administration de la recherche dans ce pays, d'un ... [more ▼]

Ce récit est le second de deux articles portant sur la naissance de la politique scientifique en Belgique. Il étudie la mutation du financement et de l'administration de la recherche dans ce pays, d'un modèle de financement privé et d'autogestion par les scientifiques à un modèle de 'Big Science' caractérisé par une forte augmentation du financement public et une direction de la science par les pouvoirs publics. [less ▲]

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See detailESA Voyage 2050 White Paper: Detecting life outside our solar system with a large high-contrast-imaging mission
Snellen, Ignas; Albrecht, Simon; Anglada-Escude, Guillem et al

E-print/Working paper (2019)

In this white paper, we recommend the European Space Agency plays a proactive role in developing a global collaborative effort to construct a large high-contrast imaging space telescope, e.g. as currently ... [more ▼]

In this white paper, we recommend the European Space Agency plays a proactive role in developing a global collaborative effort to construct a large high-contrast imaging space telescope, e.g. as currently under study by NASA. Such a mission will be needed to characterize a sizable sample of temperate Earth-like planets in the habitable zones of nearby Sun-like stars and to search for extraterrestrial biological activity. We provide an overview of relevant European expertise, and advocate ESA to start a technology development program towards detecting life outside the Solar system. <P /> [less ▲]

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See detailAtmospheric characterization of terrestrial exoplanets in the mid-infared: biosignatures, habitability & diversity
Quanz, Sascha P.; Absil, Olivier ULiege; Angerhausen, Daniel et al

E-print/Working paper (2019)

Exoplanet science is one of the most thriving fields of modern astrophysics. A major goal is the atmospheric characterization of dozens of small, terrestrial exoplanets in order to search for signatures ... [more ▼]

Exoplanet science is one of the most thriving fields of modern astrophysics. A major goal is the atmospheric characterization of dozens of small, terrestrial exoplanets in order to search for signatures in their atmospheres that indicate biological activity, assess their ability to provide conditions for life as we know it, and investigate their expected atmospheric diversity. None of the currently adopted projects or missions, from ground or in space, can address these goals. In this White Paper we argue that a large space-based mission designed to detect and investigate thermal emission spectra of terrestrial exoplanets in the MIR wavelength range provides unique scientific potential to address these goals and surpasses the capabilities of other approaches. While NASA might be focusing on large missions that aim to detect terrestrial planets in reflected light, ESA has the opportunity to take leadership and spearhead the development of a large MIR exoplanet mission within the scope of the "Voyage 2050'' long-term plan establishing Europe at the forefront of exoplanet science for decades to come. Given the ambitious science goals of such a mission, additional international partners might be interested in participating and contributing to a roadmap that, in the long run, leads to a successful implementation. A new, dedicated development program funded by ESA to help reduce development and implementation cost and further push some of the required key technologies would be a first important step in this direction. Ultimately, a large MIR exoplanet imaging mission will be needed to help answer one of mankind's most fundamental questions: "How unique is our Earth?'' [less ▲]

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See detailCommission v Germany (c-377/17): Do exceptions in tariff regulation matter?
Vandendaele, Valentin ULiege

E-print/Working paper (2019)

A blogpost on the Commission v Germany case (C-377/17) in which the Court of Justice held that German tariff regulation for architects and engineers was incompatible with the Services Directive.

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See detailNew perspectives on the Belt and Road Initiative beyond doctrinal debates
Riga, Dealan ULiege

E-print/Working paper (2019)

Interview with Richard T. Griffiths, emeritus professor of economic history and international studies at Leiden University.

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See detailLe talisman des agronomes
Royen, Virgile ULiege

E-print/Working paper (2019)

Au cours des années 30, les professeurs, étudiants et associations d'anciens élèves des instituts agronomiques belges (Gembloux, Louvain, Gand) réclamaient à cor et à cri une place plus grande pour la ... [more ▼]

Au cours des années 30, les professeurs, étudiants et associations d'anciens élèves des instituts agronomiques belges (Gembloux, Louvain, Gand) réclamaient à cor et à cri une place plus grande pour la science dans le cursus d'ingénieur agronome. Dans cet article, nous avançons l'hypothèse selon laquelle cette revendication visait moins à répondre aux progrès des techniques et aux besoins de l'agriculture qu'au chômage dont souffrait la profession : en relevant le niveau, les responsables de l'enseignement agronomique visait avant tout à réduire les effectifs étudiants. [less ▲]

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See detailImpacts of H2O variability on accuracy of CH4 observations from MIPAS satellite over tropics
Yirdaw Berhe, T.; Mengistu Tsidu, G.; Blumenstock, T. et al

E-print/Working paper (2019)

Uncertainties of tropical methane concentrations, retrieved from spectra recorded by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), MIPAS version V5R_CH4_220 are large. We explore ... [more ▼]

Uncertainties of tropical methane concentrations, retrieved from spectra recorded by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), MIPAS version V5R_CH4_220 are large. We explore the relation of these uncertainties with water vapour variability. We further show that these uncertainties have been reduced in MIPAS version V5R_CH4_224. Coincident measurements of CH4 by MIPAS, ground based FTIR and CH4 derived from EOS MLS coincident measurements of atmospheric water vapour (H2O), carbon monoxide (CO) and nitrous oxide (N2O) are used to estimate the standard uncertainty of MIPAS CH4 220, MIPAS CH4 224 and natural variability of H2O. Different methods such as bias evaluation, differential method and correlation coefficient are employed to explore the latitudinal variations of standard uncertainty of MIPAS CH4 220 and natural variability of water vapour as well as its reduction on MIPAS CH4 224. The averaged bias between MIPAS CH4 220 and ground-based FTIR measurements are −12.3 %, 8.4 % and 1.2 % for tropics, mid-latitudes and high latitudes, respectively. The standard deviations of the differences for these latitudinal bands are 5.9 %, 4.8 % and 4.7 %. More-over, the correlation coefficient between MIPAS CH4 220 and MIPAS V5R_N2O_220 is 0.32 in the upper troposphere and lower stratosphere over tropics and larger than the mod-est value 0.5 in mid and high latitudes. The poor correlation between MIPAS CH4 220 and MIPAS N2O 220 over tropics can indicate the large uncertainty of MIPAS CH4 220 over tropics that is related to water variability. Similarly, mean relative difference between MIPAS CH4 224 and ground-based FTIR measurements are 3.9 %, −2.6 % and −2.7 % in altitude 15–21 km and the average estimated uncertainty of MIPAS CH4 224 methane were obtained 2.4 %, 1.4 % and 5.1 % in altitude ranges of 15 to 27 km for tropics, mid and high latitudes, respectively. The estimated measurement uncertainty of MIPAS CH4 224 is different for the three latitude bands in the northern hemisphere, reflecting the latitudinal variation of uncertainties of MIPAS methane. However, the large reduction of uncertainty in MIPAS CH4 224 as compared to MIPAS CH4 220 has been confirmed for the tropical measurements. The correlation coefficients between the uncertainty of MIPAS CH4 220 and the variability of water vapour in lower stratosphere are strong (0.88) on monthly temporal scales. Similar methods were used for MIPAS CH4 224. It was found that the uncertainty in methane due to the variability of water vapor has been reduced. [less ▲]

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See detailThe Ultracool SpeXtroscopic Survey. I. Volume-Limited Spectroscopic Sample and Luminosity Function of M7$-$L5 Ultracool Dwarfs
Bardalez Gagliuffi, Daniella C.; Burgasser, Adam J.; Schmidt, Sarah J. et al

E-print/Working paper (2019)

We present a volume-limited, spectroscopically-verified sample of M7$-$L5 ultracool dwarfs within 25\,pc. The sample contains 410 sources, of which $93\%$ have trigonometric distance measurements ($80 ... [more ▼]

We present a volume-limited, spectroscopically-verified sample of M7$-$L5 ultracool dwarfs within 25\,pc. The sample contains 410 sources, of which $93\%$ have trigonometric distance measurements ($80\%$ from \textit{Gaia} DR2), and $81\%$ have low-resolution ($R\sim120$), near- infrared (NIR) spectroscopy. We also present an additional list of 60 sources which may be M7$-$L5 dwarfs within 25\,pc when distance or spectral type uncertainties are taken into account. The spectra provide NIR spectral and gravity classifications, and we use these to identify young sources, red and blue $J-K_S$ color outliers, and spectral binaries. We measure very low gravity and intermediate gravity fractions of $2.1^{+0.9}_{-0.8}\%$ and $7.8^{+1.7}_{-1.5}\%$, respectively; fractions of red and blue color outliers of $1.4^{+0.6}_{-0.5}$\% and $3.6^{+1.0}_{-0.9}$\%, respectively; and a spectral binary fraction of $1.6^{+0.5}_{-0.5}\%$. We present an updated luminosity function for M7$-$L5 dwarfs continuous across the hydrogen burning limit that agrees with previous studies. We estimate our completeness to range between $69-80\%$ when compared to an isotropic model. However, we find that the literature late-M sample is severely incomplete compared to L dwarfs, with completeness of $62^{+8}_{-7}\%$ and $83^{+10}_{-9}\%$, respectively. This incompleteness can be addressed with astrometric- based searches of ultracool dwarfs with \textit{Gaia} to identify objects previously missed by color- and magnitude-limited surveys. [less ▲]

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See detailPB 8783: the first sdO star suitable for asteroseismic modeling?
Van Grootel, Valérie ULiege; Randall, Suzanna K.; Latour, Marilyn et al

E-print/Working paper (2019)

Pulsating hot B subdwarf (sdB) stars, which are core-He burning objects, are one of the showcases of asteroseismology. Thanks to the combination of rich pulsation spectra and state-of-the-art modeling ... [more ▼]

Pulsating hot B subdwarf (sdB) stars, which are core-He burning objects, are one of the showcases of asteroseismology. Thanks to the combination of rich pulsation spectra and state-of-the-art modeling tools it is possible to tightly constrain fundamental parameters such as the stellar mass. There are on the contrary very few hotter sdO pulsators, which are in a more advanced evolutionary stage. Some of them are identified in Globular Clusters (GCs), but they are extremely rare in the field. Recently, it was suggested that PB8783, one of the very first sdB pulsators discovered in 1997, may in fact be an unrecognized hot sdO star with very similar properties to the GC pulsators. We present here new very high-quality spectroscopy of PB8783 as well as an asteroseismic analysis of the pulsator and answer the question: is PB 8783 the first sdO star suitable for asteroseismic modeling? [less ▲]

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See detailUnveiling two new trichome-specific promoters of Nicotiana tabacum
Pottier, Mathieu ULiege; Laterre, Raphaëlle; Van Wessem, Astrid et al

E-print/Working paper (2019)

Nicotiana tabacum has emerged as a suitable host for metabolic engineering of terpenoids and derivatives in tall glandular trichomes, which actively synthesize and secrete specialized metabolites. However ... [more ▼]

Nicotiana tabacum has emerged as a suitable host for metabolic engineering of terpenoids and derivatives in tall glandular trichomes, which actively synthesize and secrete specialized metabolites. However, implementation of an entire biosynthetic pathway in glandular trichomes requires the identification of trichome-specific promoters to appropriately drive the expression of the transgenes needed to set up the desired pathway. In this context, RT-qPCR analysis was carried out on wild-type N. tabacum plants to compare the expression pattern and gene expression level of NtRbS-T1 and NtMALD1, two newly identified genes expressed in glandular trichomes, with those of NtCYP71D16, NtCBTS2α, NtCPS2, and NtLTP1, which were reported in the literature to be specifically expressed in glandular trichomes. We show that NtRbcS-T1 and NtMALD1 are specifically expressed in glandular trichomes like NtCYP71D16, NtCBTS2α, and NtCPS2, while NtLTP1 is also expressed in other leaf tissues as well as in the stem. Transcriptional fusions of each of the six promoters to the GUS-VENUS reporter gene were introduced in N. tabacum by Agrobacterium-mediated transformation. Almost all transgenic lines displayed GUS activity in tall glandular trichomes, indicating that the appropriate cis regulatory elements were included in the selected promoter regions. However, unlike for the other promoters, no trichome-specific line was obtained for pNtLTP1:GUS-VENUS, thus in agreement with the RT-qPCR data. These data thus provide two new transcription promoters that could be used in metabolic engineering of glandular trichomes. [less ▲]

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See detailPanamá debe diseñar una hoja de ruta clara frente a China
Wintgens, Sophie ULiege

E-print/Working paper (2019)

Conceder prioridad a los intereses nacionales, diversificar los socios comerciales, defender la posición de Panamá como país neutral y fortalecer la democracia, son algunos aspectos que Panamá debe ... [more ▼]

Conceder prioridad a los intereses nacionales, diversificar los socios comerciales, defender la posición de Panamá como país neutral y fortalecer la democracia, son algunos aspectos que Panamá debe considerar para beneficiarse de la relación con China “sin perder soberanía”. [less ▲]

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See detailÀ la conquête de la politique scientifique : ‘Un effort national en faveur de la science’
Royen, Virgile ULiege

E-print/Working paper (2019)

Ce récit est le premier de deux articles portant sur la naissance de la politique scientifique en Belgique. Il étudie la mutation du financement et de l'administration de la recherche dans ce pays, d'un ... [more ▼]

Ce récit est le premier de deux articles portant sur la naissance de la politique scientifique en Belgique. Il étudie la mutation du financement et de l'administration de la recherche dans ce pays, d'un modèle de financement privé et d'autogestion par les scientifiques à un modèle de 'Big Science' caractérisé par une forte augmentation du financement public et une direction de la science par les pouvoirs publics. [less ▲]

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See detailLooking for a reference for large datasets: relative reliability of visual and automatic sleep scoring
Muto, Vincenzo ULiege; Berthomier, Christian; Schmidt, Christina ULiege et al

E-print/Working paper (2019)

Study Objectives: New challenges in sleep science require to describe fine grain phenomena or to deal with large datasets. Beside the human resource challenge of scoring huge datasets, the interand intra ... [more ▼]

Study Objectives: New challenges in sleep science require to describe fine grain phenomena or to deal with large datasets. Beside the human resource challenge of scoring huge datasets, the interand intra-expert variability may also reduce the sensitivity of such studies. Searching for a way to disentangle the variability induced by the scoring method from the actual variability in the data, visual and automatic sleep scorings of healthy individuals were examined. Methods: A first dataset (DS1, 4 recordings) scored by 6 experts plus an autoscoring algorithm was used to characterize inter-scoring variability. A second dataset (DS2, 88 recordings) scored a few weeks later was used to investigate intra-expert variability. Percentage agreements and Conger’s kappa were derived from epoch-by-epoch comparisons on pairwise, consensus and majority scorings. Results: On DS1 the number of epochs of agreement decreased when the number of expert increased, in both majority and consensus scoring, where agreement ranged from 86% (pairwise) to 69% (all experts). Adding autoscoring to visual scorings changed the kappa value from 0.81 to 0.79. Agreement between expert consensus and autoscoring was 93%. On DS2 intra-expert variability was evidenced by the kappa systematic decrease between autoscoring and each single expert between datasets (0.75 to 0.70). Conclusions: Visual scoring induces inter- and intra-expert variability, which is difficult to address especially in big data studies. When proven to be reliable and if perfectly reproducible, autoscoring methods can cope with intra-scorer variability making them a sensible option when dealing with large datasets. [less ▲]

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See detailWill Deliveroo and Uber be captured by the proposed EU platform Regulation? You’d better watch out…
Van Cleynenbreugel, Pieter ULiege

E-print/Working paper (2019)

An analysis as to why Uber and Deliveroo could be excluded from the scope of application of the envisaged EU platform Regulation

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See detailLikelihood-free MCMC with Amortized Approximate Likelihood Ratios
Hermans, Joeri ULiege; Begy, Volodimir; Louppe, Gilles ULiege

E-print/Working paper (2019)

Posterior inference with an intractable likelihood is becoming an increasingly common task in scientific domains which rely on sophisticated computer simulations. Typically, these mechanistic models do ... [more ▼]

Posterior inference with an intractable likelihood is becoming an increasingly common task in scientific domains which rely on sophisticated computer simulations. Typically, these mechanistic models do not admit tractable densities forcing practitioners to rely on approximations during inference. This work proposes a novel approach to address the intractability of the likelihood and the marginal model. We achieve this by learning a flexible estimator which approximates the likelihood-to-evidence ratio. The resulting amortized ratio estimator is embedded in MCMC samplers such as Metropolis-Hastings and Hamiltonian Monte Carlo to approximate the likelihood-ratio between consecutive states in the Markov chain, allowing us to draw samples from the intractable posterior. Techniques are presented to improve the numerical stability. We demonstrate our approach on a variety of benchmarks and compare against well-established approximate inference techniques. Scientific applications in high energy and astrophysics with high-dimensional observations show its applicability. [less ▲]

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See detailElectrochoc Numérique - Compte-rendu de la journée
De Cooman, Jérôme ULiege

E-print/Working paper (2019)

Le 13 décembre 2018 a eu lieu la conférence Électrochoc Numérique 3. En voici un résumé. Si l’on doit retenir quelque chose de cet évènement, c’est que la digitalisation des avocats est un processus ... [more ▼]

Le 13 décembre 2018 a eu lieu la conférence Électrochoc Numérique 3. En voici un résumé. Si l’on doit retenir quelque chose de cet évènement, c’est que la digitalisation des avocats est un processus inévitable dont les principaux intéressés semblent prendre conscience. Plutôt que d’avoir peur de la technologie, il faut se servir d’elle pour repenser son métier et le rapport aux clients, dans l’intérêt desquels nous devons agir. [less ▲]

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See detailLa Scandinavie, un modèle de transition énergétique ?
Merenne-Schoumaker, Bernadette ULiege

E-print/Working paper (2019)

Les pays du nord de l'Europe sont souvent cités comme modèle de la transition énergétique, non sans raison puisque la part des énergies renouvelables y est plus élevée qu'ailleurs. Une analyse comparative ... [more ▼]

Les pays du nord de l'Europe sont souvent cités comme modèle de la transition énergétique, non sans raison puisque la part des énergies renouvelables y est plus élevée qu'ailleurs. Une analyse comparative de la situation dans les 5 pays montre toutefois qu’à l'exception de l'Islande avec son potentiel géothermique, la plupart d'entre eux recourent encore largement soit aux énergies fossiles, soit au nucléaire. Il n'y a donc pas de modèle scandinave mais des situations variables selon les pays. [less ▲]

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See detailRemembering Jean-Pierre Bourguignon, MD, PhD
Parent, Anne-Simone ULiege; Zoeller, R. Thomas; Geenen, Vincent ULiege et al

E-print/Working paper (2019)

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See detailReport on HOSTS survey return
Ertel, Steve; Hinz, Phil; Mennesson, Bertrand et al

E-print/Working paper (2019)

Observations for the HOSTS (Hunt for Observable Signatures of Terrestrial Systems) survey for warm dust around nearby stars (exozodiacal dust, i.e., dust in and near their habitable zones, HZs) have been ... [more ▼]

Observations for the HOSTS (Hunt for Observable Signatures of Terrestrial Systems) survey for warm dust around nearby stars (exozodiacal dust, i.e., dust in and near their habitable zones, HZs) have been completed in the first half of 2018 (during observing semester 2018A). The goal of HOSTS was to constrain the occurrence rate and typical level of exozodiacal dust around a sample of nearby starsin order to assess the risk imposed by this dust to future space missions attempting to directly image habitable exoplanets. We here report on the immediate conclusions of the survey relevant to this goal.Detailed descriptions of the HOSTS observing strategy, data reduction, and analysis together with detailed statistical results were provided by Ertel et al. (2018a). Here, we provide only a brief summary of these points and updates where necessary. In particular, we provide the final null measurements and derived HZ dust levels (zodi levels) for all observed stars and final statistics derived from those measurements. [less ▲]

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See detailKey Technologies for the Wide Field Infrared Survey Telescope Coronagraph Instrument
Bailey, Vanessa P.; Armus, Lee; Balasubramanian, Bala et al

E-print/Working paper (2019)

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) is a high-contrast imager and integral field spectrograph that will enable the study of exoplanets and circumstellar disks at ... [more ▼]

The Wide Field Infrared Survey Telescope (WFIRST) Coronagraph Instrument (CGI) is a high-contrast imager and integral field spectrograph that will enable the study of exoplanets and circumstellar disks at visible wavelengths. Ground-based high-contrast instrumentation has fundamentally limited performance at small working angles, even under optimistic assumptions for 30m-class telescopes. There is a strong scientific driver for better performance, particularly at visible wavelengths. Future flagship mission concepts aim to image Earth analogues with visible light flux ratios of more than 10^10. CGI is a critical intermediate step toward that goal, with a predicted 10^8-9 flux ratio capability in the visible. CGI achieves this through improvements over current ground and space systems in several areas: (i) Hardware: space-qualified (TRL9) deformable mirrors, detectors, and coronagraphs, (ii) Algorithms: wavefront sensing and control; post- processing of integral field spectrograph, polarimetric, and extended object data, and (iii) Validation of telescope and instrument models at high accuracy and precision. This white paper, submitted to the 2018 NAS Exoplanet Science Strategy call, describes the status of key CGI technologies and presents ways in which performance is likely to evolve as the CGI design matures. <P /> [less ▲]

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See detailL’Institut de Botanique de l'ULiège : Transformation d'une ancienne façade en béton brut en une façade en bois de réemploi
Prégardien, Michel ULiege; Marique, Anne-Françoise ULiege

E-print/Working paper (2019)

Rénover en rémploi : présentation du projet de rénovation énergétique et patrimoniale de l'Institut de Botanique de l'ULiège

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See detailAged insulin resistant macrophages reveal dysregulated cholesterol biosynthesis, a pro-inflammatory profile and reduced foam cell formation capacity
Chabrier, G.; Hobson, S.; Yuldasheva, N. et al

E-print/Working paper (2019)

Insulin resistance is the central defining feature of type 2 diabetes and an independent risk factor for the development of atherosclerosis. In addition, aging is a major risk factor in the development of ... [more ▼]

Insulin resistance is the central defining feature of type 2 diabetes and an independent risk factor for the development of atherosclerosis. In addition, aging is a major risk factor in the development of insulin resistance and cardiovascular disease. Macrophages play a pivotal roles the the developments of diabetes and atherosclerosis and express insulin receptors. Despite their relevance however, the effect of insulin and insulin resistance on macrophages regarding their inflammatory status, foam cell formation capacity and affect on atherosclerosis are unclear. By taking advantage of a mouse model that recapitulates the effects of chronic PI3K pathway hyperstimulation in macrophages through SHIP2 knock-down, we show that insulin resistance in aged macrophages promotes a proinflammatory phenotype while modulating the cholesterol biosynthesis pathway. These altered characteristics may contribute to the development of chronic inflammatory disease frequently observed with age. Moreover, aged insulin-resistant proinflammatory macrophages display an altered response to acute inflammatory stimulus and reduced foam cell formation capacity. Our work also highlights for the first time, the complex and contrasting immunomodulatory effects of insulin on macrophages in aged mice. [less ▲]

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See detailBCCM/ULC Cyanobacteria culture collection at the University of Liège (ISO9001 certified). Version 1.5. SCAR - Microbial Antarctic Resource System. Occurrence dataset
Wilmotte, Annick ULiege; Beets, Kim ULiege; Sweetlove, Maxime

E-print/Working paper (2019)

Catalogue of cyanobacterial strains of the BCCM/ULC collection with metadata, formatted to be deposited in GBIF by Maxime Sweetlove (SCAR Antarctic Biodiversity Database)

Detailed reference viewed: 17 (0 ULiège)
See detailLa tour d'ivoire et la marée de merde: sur un texte de Simon Leys et son actualité
Thirion, Nicolas ULiege

E-print/Working paper (2019)

Le décret « définissant le paysage de l’enseignement supérieur et l’organisation académique des études », mieux connu sous l’appellation de « décret Paysage », constitue la traduction presque parfaite ... [more ▼]

Le décret « définissant le paysage de l’enseignement supérieur et l’organisation académique des études », mieux connu sous l’appellation de « décret Paysage », constitue la traduction presque parfaite, dans les limites de la Communauté française de Belgique, de certaines dérives qui affectent l’institution universitaire un peu partout dans le monde depuis un quart de siècle environ et qui, toutes, proviennent de deux tendances lourdes: l’utilitarisme à courte vue, d’un côté ; la démagogie racoleuse, de l’autre. Ce faisant, le décret "Paysage" consacre une vision de l’Université et, plus largement, de l’enseignement supérieur à contre-courant des principes et des croyances qui les ont fondés et les irriguaient encore jusqu’il y a peu. [less ▲]

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See detailGoverning the Patent Commons
Auer, Dirk ULiege; Julian, Morris

E-print/Working paper (2019)

Detailed reference viewed: 14 (0 ULiège)
See detailU-Frequent hypercyclicity notions and related weighted densities
Ernst, Romuald; Esser, Céline ULiege; Menet, Quentin

E-print/Working paper (2019)

We study dynamical notions lying between U-frequent hypercyclicity and reiterative hypercyclicity by investigating weighted upper densities between the unweighted upper density and the upper Banach ... [more ▼]

We study dynamical notions lying between U-frequent hypercyclicity and reiterative hypercyclicity by investigating weighted upper densities between the unweighted upper density and the upper Banach density. While chaos implies reiterative hypercyclicity, we show that chaos does not imply U-frequent hypercyclicity with respect to a weighted upper density. Moreover, we show that if T is U-frequently hypercyclic (resp. reiteratively hypercyclic) then the n-fold product of T is still U-frequently hypercyclic (resp. reiteratively hypercyclic) and that this implication is also satisfied for each of the considered U-frequent hypercyclicity notions. [less ▲]

Detailed reference viewed: 34 (3 ULiège)
See detailGeorge Orwell: 1984
Belleflamme, Clémence ULiege

E-print/Working paper (2019)

Résumé apéritif du roman de George Orwell intitulé 1984 (1949), rédigé dans le cadre du dossier "Les lectures pour l'été 2019" de la revue Culture.

Detailed reference viewed: 20 (2 ULiège)
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See detailJobart, Marthe
Piront, Julie ULiege

E-print/Working paper (2019)

Notice de dictionnaire consacrée à Marthe Jobart (1645-1717), en religion sœur Madeleine Thérèse de Saint-Joseph, carmélite déchaussée au premier monastère de Nancy, religieuse architecte.

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