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See detailEtude du mode de liaison des canaux potassiques de type SK et l’apamine par modélisation moléculaire
Dilly, Sébastien ULiege; Lamy, Cédric; Seutin, Vincent ULiege et al

Poster (2010, May 20)

Parmi les canaux ioniques impliqués dans le contrôle de l'activité neuronale, les canaux potassiques calcium-dépendants de basse conductance, dénommés canaux SK, constituent une cible thérapeutique ... [more ▼]

Parmi les canaux ioniques impliqués dans le contrôle de l'activité neuronale, les canaux potassiques calcium-dépendants de basse conductance, dénommés canaux SK, constituent une cible thérapeutique intéressante. En effet, ils sous-tendent la posthyperpolarisation ("AfterHyperPolarization") de durée moyenne (mAHP) qui limite l'excitabilité de divers types de neurones du système nerveux central (SNC). A ce jour, 3 types de sous-unités, SK1, SK2 et SK3, ont été identifiés dans différentes régions du cerveau. Le blocage sélectif de ces canaux pourrait être bénéfique dans le traitement de divers troubles du SNC comme la maladie de Parkinson (SK3), la dépression (SK3) ou encore les désordres cognitifs (SK2) (Liégeois et al., 2003 ; Pedarzani et al., 2008). Jusqu’à présent, le site d’interaction entre les canaux SK et leurs bloqueurs n’a pas encore été précisément élucidé. Dans ce contexte, nous avons entrepris la modélisation de ces canaux par homologie comparative en se basant sur la structure cristalline du canal potassique KCSA (Doyle et al., 1998). La construction de ces canaux constitue la première étape dans la détermination des requis structuraux essentiels à l’affinité de bloqueurs et à la compréhension des modes de liaison de ces ligands. Le mode de liaison de l’apamine, bloqueur peptidique issu du venin d’abeille, a été ensuite exploré par « docking ». Afin de confirmer ce site de liaison potentiel, des expériences de mutagénèse dirigée ont été réalisées. Les premiers canaux mutants testés dans des expériences électrophysiologiques par la technique de « patch clamp » ont permis de valider certaines données théoriques. Grâce à cette stratégie, nous espérons préciser le mécanisme d'action des bloqueurs des canaux SK et, idéalement, découvrir des pistes pour concevoir des bloqueurs sélectifs. [less ▲]

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See detailL’apprentissage au secours de la réduction de dimension pour des problèmes d’optimisation
Ben Abbes, Ala; Rachelson, Emmanuel ULiege; Diemer, Sébastien

in Actes de la Conférence Francophone d'Apprentissage (2010, May 19)

Pour assurer la stabilité du réseau électrique, la production doit être ajustée en quasi temps réel à la consommation. Cet ajustement ne peut porter que sur un nombre limité de centrales et doit être ... [more ▼]

Pour assurer la stabilité du réseau électrique, la production doit être ajustée en quasi temps réel à la consommation. Cet ajustement ne peut porter que sur un nombre limité de centrales et doit être effectué dans des délais réduits. La combinatoire du problème rend la recherche d’un optimum économique par des méthodes d’optimisation classiques très difficile. Ce travail cherche à montrer l’intérêt d’utiliser des algorithmes d’apprentissage supervisé performants comme le Boosting, pour sélectionner les centrales à redéclarer. Cette sélection préalable permet ensuite de réduire considérablement le temps de l’optimisation des programmes de production tout en garantissant l’optimalité économique. [less ▲]

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See detailPerte et ressources dans les nouvelles familles: le cas des familles recomposées
D'Amore, Salvatore ULiege; Gresse, Karin; Pauss, Véronique

Conference (2010, May 19)

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See detailFrom defects to causes: pathology of concrete and investigation methods.
Courard, Luc ULiege; Van der Wielen, Audrey ULiege; Darimont, Anne ULiege

in Startegjia Izvedbe Sanacij Objektov (2010, May 19)

The proper planning of investigations before carrying out repair works is important if optimum use is to be made of the test data. A major step needs to be taken from knowing, for example, that chloride ... [more ▼]

The proper planning of investigations before carrying out repair works is important if optimum use is to be made of the test data. A major step needs to be taken from knowing, for example, that chloride is present in the concrete, to select the best methods for repair. Engineers require guidance on both the techniques available for the condition assessment of structures and the methods for data interpretation. Two major stages are usually recommended for such an operation: the first stage is based on a rapid-scan visual assessment, often including limited sampling in areas obviously damaged, from which areas can be selected for more detailed investigations. The second stage contains a detailed diagnostic survey that relies on destructive and non destructive testing techniques. Non destructive techniques are more and more utilized not only for the evaluation of the concrete strength but also for the detection of cracks and delaminations. Moreover, the interest for techniques able to evaluate concrete permeability is rising, due to the importance of this factor for durability evaluation. The paper will discuss the assessment of concrete structures and describe the main destructive and non destructive techniques with regard to specific pathologies. [less ▲]

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See detailConclusions : à quelles conditions pouvons-nous travailler ensemble?
Dozo, Björn-Olav ULiege; Clavert, Frédéric

Conference (2010, May 19)

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See detailDe la prévention chronologique à la prévention relationnelle; la prévention quaternaire comme tâche du médecin de famille.
Jamoulle, Marc ULiege

Poster (2010, May 19)

La prévention clinique est traditionnellement exprimée comme une vue du médecin sur une tâche à réaliser avant la survenue d’un évènement. Initiée par Leavell et Clark en 1958 elle est complétée en 1988 ... [more ▼]

La prévention clinique est traditionnellement exprimée comme une vue du médecin sur une tâche à réaliser avant la survenue d’un évènement. Initiée par Leavell et Clark en 1958 elle est complétée en 1988 par J-A Bury qui dénomme prévention quaternaire les soins palliatifs.Le paradigme change, le patient devient central aux soins, la prévention clinique est perçue au travers de la relation entre le médecin et le patient. Le croisement de la science du médecin et de la conscience du patient permet de répartir la prévention en quatre champs. Elle est traversée en oblique par la ligne du temps. Cette proposition (Jamoulle, 1986) a été avalisée par la Wonca et l’UEMO et permet de cadrer quatre concepts de prévention clinique. [less ▲]

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See detailles stéréotypes sexués à l'adolescence et les enjeux scolaires
Gavray, Claire ULiege

Conference (2010, May 19)

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See detailThe occurrence of multicolored ladybird, Harmonia axyridis Pallas, a biological control agent in agroecosystems in Wallonia
Vandereycken, Axel ULiege; Durieux, Delphine ULiege; Haubruge, Eric ULiege et al

Conference (2010, May 18)

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations in greenhouses. It took only few years to the insect to get adapted ... [more ▼]

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations in greenhouses. It took only few years to the insect to get adapted to temperate climate conditions and to spread out all over Europe. Now, H. axyridis is one of the coccinellid with the biggest size in Belgium, causing damages to the ecosystems through e.g. intraguild predation (IGP). We are still lacking information about the consequences of the introduction of this superpredator in our agro-ecosystems. This work focuses on the potential impacts of H. axyridis on the entomofauna associated with several crops (potatos, corn, wheat, broad bean). We evaluated in 2009 the occurrence as well as the interactions between aphids and their natural enemies (hoverflies, coccinellids and lacewings) in several agro-ecosystem sites in northern Wallonia. After one year of field observations, were found thirteen coccinellid species, most of the catched individuals being H. axyridis with 64% of the coccinellids, Propylea 14-punctata, 15%, or Coccinella 7-punctata, 14%. This invasive ladybird dominates the group of coccinellids generally in all crops in north Wallonia. The results with the sticky traps show that the maximum occurrence of H. axyridis in crops is observed in chicory, sugar beet and potatoes. The relationship aphid-ladybird in wheat for example, brings out that increase of density of Asian ladybird in mid-July follow the increase of aphids (Sitobion avenae, Sitobion fragariae, Metopolophium dirhodum, Aphis fabae) in the end of June. We also observe that, in most agro-ecosystems, hoverflies and lacewings are the dominant aphid natural enemies. In all crops investigate, the multicolored ladybird occurs with 5% of the aphidophagous after the Chrysopidae, 12% and the Syrphidae, 76%. In 2009, the agro-ecosystems with the most aphidophagous species are carrot and broad bean and these habitats are dominated by hoverflies. [less ▲]

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See detailComputational study of the error distribution in right-censored and selection-biased regression models
Laurent, Géraldine ULiege; Heuchenne, Cédric ULiege

Conference (2010, May 18)

Consider the regression model Y = m(X) + σ(X) Ɛ where m(X) =E [Y|X] and σ²(X) = Var [Y|X] are unknown smooth functions and the error Ɛ, with unknown distribution, is independent of X. The pair (X,Y) is ... [more ▼]

Consider the regression model Y = m(X) + σ(X) Ɛ where m(X) =E [Y|X] and σ²(X) = Var [Y|X] are unknown smooth functions and the error Ɛ, with unknown distribution, is independent of X. The pair (X,Y) is subject to generalized selection bias and the response to right censoring. We construct a new estimator for the cumulative distribution function of the error Ɛ, and develop a bootstrap technique to select the smoothing parameter involved in the procedure. The estimator is studied via extended simulations and applied to real unemployment data. [less ▲]

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See detailThe partial proportional odds model in the analysis of
Donneau, Anne-Françoise ULiege

Conference (2010, May 18)

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See detailStructuring effects of different lecithins on palm oil-based blends
Danthine, Sabine ULiege; Delacharlerie, Sophie ULiege; Flöter, Eckhard

Conference (2010, May 18)

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See detailBiological control using Episyrphus balteatus (De Geer) (Diptera: Syrphidae)
Leroy, Pascal ULiege; Verheggen, François ULiege; Capella, Quentin et al

Poster (2010, May 18)

Augmentative biocontrol constitutes a safe way to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer ... [more ▼]

Augmentative biocontrol constitutes a safe way to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer) (Diptera: Syrphidae) is a promising candidate for aphid biological control: larvae of this syrphid attack and consume a wide range of aphid species and are found on many vegetable crops. Because natural populations of beneficials are not always sufficient to regulate the pest infestations, this work has focused on the conception of a biological control device containing syrphid eggs which can easily be introduced in fields or greenhouses. Using semiochemicals [E-(β)-farnesene, R-(+)-limonene and (Z)-3-hexenol], honeydews and “artificial honeydews” (10% or 30% aqueous solutions of sucrose, fructose and glucose), the syrphid oviposition was artificially induced on an inert surface. To test and validate the biological control device described above, laboratory and field experiments were performed: a plastic lamella covered with syrphid eggs was suspended on aphid infested plants in order to measure the efficiency of the device. The results obtained were promising since populations of 500 aphids were eliminated in ten days when 15 syrphid eggs were introduced. The use of such a biological control device could certainly contribute to aphid biological control strategies. [less ▲]

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See detailA l’interface de l’humain et du non-humain : apprendre à être affecté.
Strivay, Lucienne ULiege

Conference (2010, May 18)

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See detailThe modified Reyment's multivariate coefficient of variation
Zhang, Lixin ULiege

Conference (2010, May 18)

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See detailJupiter's and Saturn's auroras as observed by the Hubble Space Telescope
Nichols, J. D.; Grodent, Denis ULiege

Conference (2010, May 17)

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See detailA Far-UV Imager for the Jupiter Ganymede Orbiter
Bunce, E. J.; Molyneux, P.; Bannister, N. et al

Poster (2010, May 17)

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See detailAccompagner une réforme vers des programmes visant le développement de compétences – difficultés et leviers –
Poumay, Marianne ULiege; Tardif, Jacques

Conference (2010, May 17)

En 2007, au sein de l’Université de Liège, l’IFRES a lancé un programme interne de financement et d’accompagnement de projets facultaires. Dans les projets sélectionnés, les enseignants s’engageaient à ... [more ▼]

En 2007, au sein de l’Université de Liège, l’IFRES a lancé un programme interne de financement et d’accompagnement de projets facultaires. Dans les projets sélectionnés, les enseignants s’engageaient à progresser concrètement dans l’opérationnalisation de formations orientées vers le développement de compétences chez leurs étudiants. A travers ce programme « compétences », l’objectif de l’IFRES était d’amorcer des réformes qui visent l’amélioration de l’apprentissage des étudiants. Suite à la nécessaire description de l’initiative et de quelques résultats concrets, le présent article mentionne brièvement les difficultés d’ordre institutionnel ou organisationnel et s’attarde surtout à déterminer et illustrer des problèmes conceptuels qui se posent dans ce type de réforme. Il mentionne certains freins et facteurs facilitateurs, soulignant entre autres l’intérêt d’un accompagnement semi-collectif par un consultant externe (en l’occurrence Jacques Tardif) et d’une large communication sur les avancées des projets en cours. [less ▲]

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See detailGeometrical Effects on the Dynamical Behavior of MEMS structures
Pustan, Marius ULiege; Golinval, Jean-Claude ULiege; Rochus, Véronique ULiege

(2010, May 16)

The influence of geometrical dimensions on the dynamical behavior of polysilicon MEMS structures configurations is studied and presented in this paper. Electrostatically actuated MEMS components as ... [more ▼]

The influence of geometrical dimensions on the dynamical behavior of polysilicon MEMS structures configurations is studied and presented in this paper. Electrostatically actuated MEMS components as microbridges and microcantilevers are used to investigate the coupled electro-mechanic effect, frequency responses and the dynamic bending stress. The electrostatic principle is common in sensing and acting devices and there are many MEMS structures subjected to electrostatic forces. [less ▲]

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See detailImpact de tests formatifs en ligne sur l’implication et la perception de leur utilité par des étudiants en médecine vétérinaire
Hanzen, Christian ULiege; Crahay, Vinciane ULiege; Detroz, Pascal ULiege et al

in Proceedings du 26ème congrès (2010, May 15)

La dynamique motivationnelle des étudiants est un phénomène complexe. Les activités d’évaluation sont de nature à influencer ses principaux déterminants que sont la perception que l’étudiant a de sa ... [more ▼]

La dynamique motivationnelle des étudiants est un phénomène complexe. Les activités d’évaluation sont de nature à influencer ses principaux déterminants que sont la perception que l’étudiant a de sa compétence et du contrôle qu’il peut opérer sur une activité d’apprentissage fusse-t-elle évaluative. Par ailleurs elles sont également de nature à renforcer son degré de persévérance et donc à mettre en œuvre des stratégies d’auto-motivation. Ce constat nous a incités à mettre en place au cours de l’année académique 2009-2010 un design d’évaluation des 268 étudiants de 2ème graduat en médecine vétérinaire (5ème année du cursus). Il concerne les 40 heures d’enseignements théoriques du cours de Thériogenologie des animaux de production. Dix tests formatifs constitués de 10 questions à choix multiples avec solutions générales implicites et degrés de certitude (+20/-20) ont été hebdomadairement proposés durant le premier semestre de l’année académique 2009-2010. Ces tests d’une durée de 20 minutes ont en ligne mis à disposition des étudiants via la plateforme Exams. L’ensemble des 100 questions a fait l’objet d’un dernier test préparatif deux semaines avant le test certificatif de 60 questions organisé au cours de la première semaine du mois de janvier 2010. Chaque test a été suivi 24 heures plus tard de retroactions individuelles (corrections des questions et justifications des réponses correctes) et de groupe (résultats nominatifs de tous les étudiants). Les étudiants ont par ailleurs été invités à remplir un questionnaire de satisfaction avant leur passation du test certificatif. Au travers de ce design nous souhaitions répondre à différentes questions relatives à l’implication et à la démarche réflexive des étudiants à l’encontre des activités d’évaluation proposées. Ainsi en ce qui concerne leur implication avons-nous cherché à savoir (1) leur degré de participation aux tests formatifs, (2) son évolution au cours du temps, (3) leur degré de persévérance, (4) l’effet de leur persévérance sur leur degré de réussite non seulement aux tests formatifs mais également certificatif, (5) leur utilisation des degrés de certitude (6) son évolution au cours du temps et (7) les différences éventuelles existant entre les filles et les garçons. De même en ce qui concerne l’analyse de leur démarche réflexive avons-nous cherché à préciser (1) leur sentiment de validité du score obtenu c’est-à-dire sa capacité à refléter ce qu’il prétendait mesurer, (2) leur sentiment à l’encontre de l’impact des degrés de certitude sur leurs résultats, (3) l’impact des retro-actions individuelles et de groupe fournies après chaque évaluation pour interpréter leurs performances, (4) réguler leurs apprentissages, (5) l’impact émotionnel de la comparaison avec les résultats des collègues, (6) les différences éventuelles entre les garçons et les filles. [less ▲]

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See detail3D Modelling of the Black Sea northwestern Shelf Ecosystem
Capet, Arthur ULiege; Grégoire, Marilaure ULiege

Conference (2010, May 14)

Some validation procedures are presented concerning the physicis and the biology, as well as the decomposition of the oxygen cycle in its different components. The role of the Sevastopol eddy of retaining ... [more ▼]

Some validation procedures are presented concerning the physicis and the biology, as well as the decomposition of the oxygen cycle in its different components. The role of the Sevastopol eddy of retaining POM in the Crimea peninsula causing intense bacterial oxygen consumption is evidenced. [less ▲]

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See detailA paleolimnological study of Lake Kivu (East Africa)
Knops, Sébastien; Darchambeau, François ULiege; Verleyen, Elie et al

Conference (2010, May 13)

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See detailAdolescence et délinquances : quand la puberté s’en mêle …De l’intérêt d’une approche biopsychosociale de la délinquance adolescentaire
Glowacz, Fabienne ULiege

Conference (2010, May 13)

De nombreuses recherches (Kaltiala-Heino et al., 2003 ; Parent et al., 2003 ; Beaver § Wright, 2005 ; Haynie § Piquero 2006 ; Lynne et al., 2007,..) ont établi ces dernières années un lien entre le ... [more ▼]

De nombreuses recherches (Kaltiala-Heino et al., 2003 ; Parent et al., 2003 ; Beaver § Wright, 2005 ; Haynie § Piquero 2006 ; Lynne et al., 2007,..) ont établi ces dernières années un lien entre le développement pubertaire et l’engagement à l’adolescence dans des comportements délictueux, usage de drogue, conduites sexuelles et autres comportements exploratoires et déviants. Felson et Haynie (2002) affirment que le développement pubertaire a des effets sur différents types de délinquance comparables à d’autres puissants prédicteurs de la délinquance. Bien que l’étude de Williams et Dunlop (1999) constate que les garçons à maturité précoce et tardive présentent des taux plus élevés de délinquance que leurs pairs à maturation normale, des recherches plus récentes (Ge et al., 2002 ; Beaver § Wright, 2005 ; Michaud et al., 2006 ; Lynne et al., 2007…) soutiennent l’hypothèse de la précocité pubertaire en tant que facteur de risque : les garçons à puberté précoce ont un plus haut niveau d’engagement dans des comportements délinquants et agressifs, alors que les garçons à puberté tardive s’engagent dans moins de délinquances (de type crime, violence, atteintes aux biens, usage de drogue). La délinquance sexuelle juvénile, au croisement de la délinquance et de la sexualité, incite à un questionnement sur les effets de la puberté au niveau des conduites sexuelles déviantes. Notre recherche « Adolescence, délinquances et processus pubertaire » portant sur un échantillon de 316 adolescents âgés de 13 à 18 ans, a notamment évalué l’incidence du timing pubertaire au niveau de l’adoption de conduites délinquantes sexuelles et non sexuelles. Nos résultats confirment la pertinence de la prise en compte du développement pubertaire dans les processus de socialisation et d’engagement dans la délinquance générale et/ou sexuelle à l’adolescence. [less ▲]

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See detailvandaliser à l'adolescence
Gavray, Claire ULiege; vettenburg, Nicole

Conference (2010, May 13)

The personal factor which explain vandalism amongst adolescents differ according to gender group. In the male group, we find an important impact of the valuation of violence and of the feeling of social ... [more ▼]

The personal factor which explain vandalism amongst adolescents differ according to gender group. In the male group, we find an important impact of the valuation of violence and of the feeling of social and statutory victimisation. In the female group, we find track of early victimisation in the family and the other spheres. [less ▲]

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See detailJusqu'où va-t-on au nom de l'éthique? La lutte antidopage en cyclisme sur route
Fincoeur, Bertrand ULiege

Conference (2010, May 13)

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See detailL'inventaire du bois mort à terre
Ligot, Gauthier ULiege; Rondeux, Jacques ULiege

Poster (2010, May 12)

Le bois mort à terre est devenu un indicateur reconnu de la biodiversité et de la gestion durable des forêts. Il importe donc de pouvoir apprécier les quantités de mort à l'hectare. Choisir la méthode d ... [more ▼]

Le bois mort à terre est devenu un indicateur reconnu de la biodiversité et de la gestion durable des forêts. Il importe donc de pouvoir apprécier les quantités de mort à l'hectare. Choisir la méthode d'échantillonnage à utiliser reste une tâche ardue bien qu'il existe une abondante littérature sur le sujet. Ce poster compare deux techniques généralement utilisées : les placettes de taille fixe et les transects. Nous avons évalué ces deux méthodes aussi bien à l'échelle locale que nationale et au travers de simulations statistiques nous en avons évalué la précision et l'efficacité. De plus, nous mettons en évidence l'importance d'utiliser des fonctions de conversion des estimations obtenues dans un but d'harmonisation internationale des résultats. [less ▲]

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See detailTypologie des chênaies de la Région wallonne
Perin, Jérôme ULiege; Brostaux, Yves ULiege; Claessens, Hugues ULiege

Poster (2010, May 12)

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See detailL'inventaire forestier national permanent du Grand-Duché de Luxembourg, aide au monitoring de la biodiversité
Alderweireld, Matthieu ULiege; Kugener, Georges; Wagner, Marc et al

Poster (2010, May 12)

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See detailAvifaune forestière - Etude d'habitat du Pic mar
Lehaire, François ULiege; Paquet, Jean-Yves; Delahaye, Laurence et al

Poster (2010, May 12)

En tant que bio-indicateurs, les espèces spécialistes des grands massifs forestiers feuillus ont un intérêt pour l'étude et le suivi de la diversité de ces milieux.

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See detailL'inventaire forestier national permanent du Grand-Duché de Luxembourg, aperçu de la méthodologie
Alderweireld, Matthieu ULiege; Kugener, Georges; Wagner, Marc et al

Poster (2010, May 12)

L'inventaire forestier national du Grand-Duché de Luxembourg assure depuis 1998 la mesure par échantillonnage des 89 000 ha de forêt que compte le pays. La collecte des données s'étale sur 3 ans et est ... [more ▼]

L'inventaire forestier national du Grand-Duché de Luxembourg assure depuis 1998 la mesure par échantillonnage des 89 000 ha de forêt que compte le pays. La collecte des données s'étale sur 3 ans et est réalisée tous les 10 ans au niveau d'unités d'échantillonnage à placettes concentriques. Ces données concernent tous les aspects de la forêt dans l'esprit de multifonctionnalité qui lui est assigné. [less ▲]

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See detailQualité de vie en oncologie pédiatrique : analyse comparative d’enfants en et hors traitements au moyen d’un outil modulaire
Missotten, Pierre ULiege; Dupuis, Gilles; Hoyoux, Claire et al

Conference (2010, May 12)

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See detailQualité de vie chez les enfants atteints de cancer ou non : Évaluation générique et modulaire
Fonseca, Marta; Missotten, Pierre ULiege; Etienne, Anne-Marie ULiege et al

Conference (2010, May 12)

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See detailNetwork Distance Prediction Based on Decentralized Matrix Factorization
Liao, Yongjun ULiege; Geurts, Pierre ULiege; Leduc, Guy ULiege

in Lecture Notes in Computer Science (2010, May 11), 6091

Network Coordinate Systems (NCS) are promising techniques to predict unknown network distances from a limited number of measurements. Most NCS algorithms are based on metric space embedding and suffer ... [more ▼]

Network Coordinate Systems (NCS) are promising techniques to predict unknown network distances from a limited number of measurements. Most NCS algorithms are based on metric space embedding and suffer from the inability to represent distance asymmetries and Triangle Inequality Violations (TIVs). To overcome these drawbacks, we formulate the problem of network distance prediction as guessing the missing elements of a distance matrix and solve it by matrix factorization. A distinct feature of our approach, called Decentralized Matrix Factorization (DMF), is that it is fully decentralized. The factorization of the incomplete distance matrix is collaboratively and iteratively done at all nodes with each node retrieving only a small number of distance measurements. There are no special nodes such as landmarks nor a central node where the distance measurements are collected and stored. We compare DMF with two popular NCS algorithms: Vivaldi and IDES. The former is based on metric space embedding, while the latter is also based on matrix factorization but uses landmarks. Experimental results show thatDMF achieves competitive accuracy with the double advantage of having no landmarks and of being able to represent distance asymmetries and TIVs. [less ▲]

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See detailAbsorbing layers for shallow water models
Modave, Axel ULiege; Deleersnijder, Eric; Delhez, Eric ULiege

Conference (2010, May 11)

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See detailLe(s) génocide(s) vu(s) par des jeunes : représentations et localisations
Grandjean, Geoffrey ULiege

Conference (2010, May 10)

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See detailPoor managerial competences: three typical failure patterns for small firms
Crutzen, Nathalie ULiege; Van Caillie, Didier ULiege

Conference (2010, May 10)

After an in-depth review of the scientific literature dedicated to (small) business failure causes (Crutzen and Van Caillie, 2008), it comes out that mismanagement is, by far, the failure cause which is ... [more ▼]

After an in-depth review of the scientific literature dedicated to (small) business failure causes (Crutzen and Van Caillie, 2008), it comes out that mismanagement is, by far, the failure cause which is the most commonly evoked by previous researchers (Argenti, 1976; Wichman, 1983; Newton, 1985; O'Neill and Duker, 1986; Thornhill and Amit, 2003). Nevertheless, the concept of « mismanagement » is relatively vague and large (Bruno et al., 1987; Sheldon, 1994). It is thus now necessary to clarify it if one wants to better understand the causes of small business failure and, in fine, to better prevent this phenomenon (Argenti, 1976). In particular, it is essential to distinguish between the main categories of managerial problems small businesses can be faced to in order to be able to better anticipate their failure (thanks to adequate trainings, for example) and in order to propose adequate remedies to specific managerial problems small distressed firms are confronted to. In this context, the current article identifies, on the basis of two complementary statistical analyses, three specific patterns for badly-managed firms, amongst a sample of 91 small distressed firms. [less ▲]

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See detailL’utilisation de la carte mentale en science politique : pertinence et limites
Breux, Sandra; Reuchamps, Min ULiege; Loiseau, Hugo

Conference (2010, May 10)

In this presentation, we offer insight about the use of mental map in political science

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See detailDe Paepe-Willems Award 2010: Optimization and analysis of lock gates in the framework of the Seine-Escaut Est waterway upgrading
Gernay, Thomas ULiege

Conference (2010, May 10)

This paper presents a research study performed lock gates. It concerns the downstream lock gates of the one of the four new locks planned within the framework of the “Seine-Escaut Est (SEE)” project in ... [more ▼]

This paper presents a research study performed lock gates. It concerns the downstream lock gates of the one of the four new locks planned within the framework of the “Seine-Escaut Est (SEE)” project in the Walloon Region of Belgium. At the stage of the basic preliminary design, it was decided to use four identical gates, all suspended and manoeuvred by lateral movement. On this basis, the present work tackles with different aspects of the lock gate study. The aim is double: on one hand, to advance in the study of the solution of the four downstream lock gates of the SEE project, and the other hand, to concentrate more particularly on the lock gate analysis, among which their design, optimization and structural behavior in the case of ship impact. We began with the design and optimization of the gate. This work was realized with the LBR5 lock gate optimization software, according to a method comparing a representative number of optimized solutions considering at the same time the cost and weight aspects of the structure. This method leaded to an optimized solution of the downstream gate on which further studies are concentrated. Indeed this optimized gate was modeled with the non linear finite elements software FINELG. This program was used to conduct a non linear numerical analysis of the effect of a boat impact on the downstream gate. Several analyses were performed that allowed us to discuss on the influence of the stiffener dimensions and the influence of the impact zone on the gate structural behavior submitted to the impact. Two different behaviors have been brought to light, a ductile one and a fragile one. The results of the numerical analysis with finite elements have underlined the importance of the development of a global plastic mechanism with the purpose of dissipating a large amount of energy. Finally, we have used an analytical model to calculate the gate theoretical strength in a case of a ship impact, and to compare this value with the FEM numerical analysis results. [less ▲]

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See detail« Dessinez la Belgique » : une approche par carte mentale du fédéralisme belge
Flaba, Elodie ULiege; Grandjean, Geoffrey ULiege; Reuchamps, Min ULiege

Conference (2010, May 10)

In this communication, we present how useful can mental maps be in political science through the example of the research "Draw Belgium".

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See detailVers un apprentissage subquadratique pour les mélanges d’arbres
Schnitzler, François ULiege; Leray, Philippe; Wehenkel, Louis ULiege

Conference (2010, May 10)

We consider randomization schemes of the Chow-Liu algorithm from weak (bagging, of quadratic complexity) to strong ones (full random sampling, of linear complexity), for learn- ing probability density ... [more ▼]

We consider randomization schemes of the Chow-Liu algorithm from weak (bagging, of quadratic complexity) to strong ones (full random sampling, of linear complexity), for learn- ing probability density models in the form of mixtures of Markov trees. Our empirical study on high-dimensional synthetic problems shows that, while bagging is the most accurate scheme on average, some of the stronger randomizations remain very competitive in terms of accuracy, specially for small sample sizes. [less ▲]

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See detailIntérêt du trajet de soins en néphrologie
Krzesinski, Jean-Marie ULiege

Conference (2010, May 09)

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See detailHypertension durant la grossesse
Krzesinski, Jean-Marie ULiege

Conference (2010, May 08)

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See detailLa concurrence mémorielle
Grandjean, Geoffrey ULiege

Conference (2010, May 07)

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See detailRisk assessment of soil compaction in Walloon Region (Belgium)
Rosiere, Charlotte ULiege; Delvoie, Simon ULiege; Charlier, Robert ULiege et al

Poster (2010, May 07)

The proposed Soil Framework Directive COM(2006)232 requires Member States to identify areas at risk of erosion, decline in organic matter, salinisation, compaction, sealing and landslides, as well as to ... [more ▼]

The proposed Soil Framework Directive COM(2006)232 requires Member States to identify areas at risk of erosion, decline in organic matter, salinisation, compaction, sealing and landslides, as well as to set up an inventory of contaminated sites. The present project aims to identify the susceptibility to compaction of soils of the Walloon Region (Belgium) and to recommend good farming practices avoiding soil compaction as far as possible. Within this scope, the concept of precompression stress (Pc) (Horn and Fleige, 2003) was used. Pc is defined as the maximum major principal stress that a soil horizon can withstand against any applied external vertical stress. If applied stress is higher than Pc, the soil enters in a plastic state, not easily reversible. For a given soil, the intensity of soil compaction is mainly due to the applied load which depends on vehicle characteristics (axle load, tyre dimensions, tyre inflation pressure, and vehicle velocity). To determine soil precompression stress, pedotransfert functions of Lebert and Horn (1991) defined at two water suctions (pF 1.8 and 2.5) were used. Parameters required by these functions were found within several databases (Aardewerk and Digital Map of Walloon Soils) and literature. The validation of Pc was performed by measuring stress-strain relationships using automatic oedometers. Stresses of 15.6, 31, 3, 62.5, 125, 250, 500 and 1000 kPa were applied for 10 min each. In this study, the compaction due to beet harvesters was considered because the axle load can exceed 10 tons and these machines are often used during wet conditions. The compaction at two depth levels was considered: 30 and 50 cm. Compaction of topsoil was not taken into account because, under conventional tillage, the plough depth is lower than 25 cm. Before and after the passage of the machines, following measurements were performed: granulometry, density, soil moisture, pF curve, Atterberg limits, ... The software Soilflex (Keller et al., 2007) was used to estimate the distribution of the vertical stresses sigma z in the soil. Comparison was performed between sigma z and Pc. The following data simulated the passage of a beet harvester machine (mass: 23 580 kg; load: 18 000 kg) in a silty soil located in Hesbaye and classified as Aba (Sirjacobs et al., 2000). The passage of the machine would create a Pc of around 100 kPa at 30 cm depth, while the stress induced by the machine would reach 240 kPa. In the field borders, where more vehicle traffic was usually observed and where the soil was over consolidated, Pc would reach 180 kPa, while sigma z would be 220 kPa. In both cases, the risk of compaction created by the passage of the machine would be high. [less ▲]

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See detailMémoire(s) en question(s) : la transmission entre monopole et concurrence
Vanesse, Marc ULiege

Conference (2010, May 07)

Colloque sur les difficultés rencontrées par les scientifiques pour transmettre certains épisodes douloureux de l'histoire (Holocauste, génocides, guerres) et la concurrence qui peut exister entre ... [more ▼]

Colloque sur les difficultés rencontrées par les scientifiques pour transmettre certains épisodes douloureux de l'histoire (Holocauste, génocides, guerres) et la concurrence qui peut exister entre certains gardiens de la mémoire. [less ▲]

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See detailInfluence Des Conditions Extérieures Sur Le Comportement Au Séchage d'un Milieu Poreux
Kahlerras, Loubna ULiege; Belhamri, Azeddine

Poster (2010, May 07)

Ce travail se propose d’analyser les phénomènes du séchage convectif d’un milieu poreux non saturé. Le modèle de calcul considère le couplage des équations de la couche limite et celles qui décrivent le ... [more ▼]

Ce travail se propose d’analyser les phénomènes du séchage convectif d’un milieu poreux non saturé. Le modèle de calcul considère le couplage des équations de la couche limite et celles qui décrivent le transfert de chaleur et de masse dans un milieu poreux, ayant les caractéristiques du béton renforcé avec des coupeaux de bois. La simulation effectuée montre l’effet de certains paramètres pertinents du matériau comme la température initiale et l’humidité initiale, sur le processus du séchage [less ▲]

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See detailModeling high-temperature superconductors containing an array of holes
Vanderheyden, Benoît ULiege; Lousberg, Grégory; Ausloos, Marcel ULiege et al

Conference (2010, May 07)

We have recently implemented a finite-element model for the penetration of the magnetic flux inside a bulk superconductor containing an array of holes (thin-wall superconductor), with the help of the open ... [more ▼]

We have recently implemented a finite-element model for the penetration of the magnetic flux inside a bulk superconductor containing an array of holes (thin-wall superconductor), with the help of the open-source code GetDp. In this talk, I introduce the A-phi formulation used, with edge elements and spanning tree gauges. I explain how a time-iterative method allows one to make calculations with fewer time steps, and compare the obtained results with those derived by the Brandt method. [less ▲]

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See detailJoséphisme et sécularisation
Henneau, Marie-Elisabeth ULiege

Conference (2010, May 07)

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See detailSTEM CELL IN THE TREATMENT OF TENDONITIS IN EQUINE PATIENTS
Verwilghen, Denis ULiege; Briquet, Alexandra ULiege; Gothot, André ULiege et al

Poster (2010, May 07)

Detailed reference viewed: 126 (28 ULiège)
See detailImpact of Greenland and Antarctic ice sheet interactions on model climate sensitivity
Goelzer, H; Huybrechts, P; Loutre, M-F et al

Conference (2010, May 07)

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Peer Reviewed
See detailComparison between in situ and satellite surface temperature in the Western Mediterranean Sea
Alvera Azcarate, Aïda ULiege; Barth, Alexander ULiege; Troupin, Charles ULiege et al

Conference (2010, May 06)

A comparison between satellite and in situ sea surface temperature (SST) data in the Western Mediterranean Sea in 1999 is realised. The aim of this study is to better understand the differences between ... [more ▼]

A comparison between satellite and in situ sea surface temperature (SST) data in the Western Mediterranean Sea in 1999 is realised. The aim of this study is to better understand the differences between these two data sets, in order to realise merged maps of SST using satellite and in situ data. When merging temperature from different platforms, it is crucial to take the expected RMS error of the observations into account and to correct for possible biases. Advanced Very High Resolution Radiometer (AVHRR) SST day-time and night-time satellite data are used, and the in situ data have been obtained from various databases (World Ocean Database’05, Coriolis, Medar/Medatlas and ICES). Statistics about the differences due to the hour of the day, the month of the year, the type of sensor/platform used (CTD, XBT, drifter, etc) and the spatial distribution are made using a combination of error measures, diagrams and statistical hypothesis testing. In addition to quantify the errors between different platforms, several assumptions often made when creating gridded analyses will be critically reviewed: unbiased data sets, non-correlated errors of the observations, spatially uniform variance, and Gaussian-distributed data. [less ▲]

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See detailTraduire les effets de rupture: le style de Céline en italien
Benzoni, Pietro ULiege

Conference (2010, May 06)

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See detailOn the local operational geomagnetic index K calculation
Stankov, Stan; Stegen, Koen; Wautelet, Gilles ULiege et al

Poster (2010, May 06)

Detailed reference viewed: 37 (4 ULiège)
See detailChallenging Combinatorial Problems
Crama, Yves ULiege

Conference (2010, May 06)

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See detailAuroral footprints; everywhere
Grodent, Denis ULiege; Bonfond, Bertrand ULiege; Radioti, Aikaterini ULiege et al

Conference (2010, May 06)

Jupiter’s moons Io, Europa and Ganymede are continuously interacting with the Jovian magnetic field and with the sheet of plasma flowing near its equatorial plane. The interaction between these moons and ... [more ▼]

Jupiter’s moons Io, Europa and Ganymede are continuously interacting with the Jovian magnetic field and with the sheet of plasma flowing near its equatorial plane. The interaction between these moons and the Jovian magnetosphere causes strong Alfvénic perturbations which propagate along the magnetic field lines. On their way towards Jupiter’s polar regions, these perturbations accelerate charged particles which then interact with Jupiter’s ionosphere where they loose a fraction of their energy in the form of auroral emissions. Each of the three moons leaves an auroral footprint around the poles of Jupiter which departs from the bulk of the auroral emission. Their location is mainly controlled by the topology of the field lines and thus analysis of the auroral footprints provides information on the magnetic field itself. In that regard, the satellites auroral footpaths were used to highlight the presence of a strong magnetic anomaly in the northern hemisphere of Jupiter. Detailed inspection of the footprints’ brightness and morphology as a function of time reveals fundamental information on the interaction mechanisms near the moons, on the particles acceleration mechanisms as well as on the Jovian ionosphere. For example, it was suggested that the Io footprint actually consists of several spots resulting from successive steps in the perturbation propagation process. Another example is the finding of three different timescales in the variations of Ganymede’s footprint; each of them is pointing to a different part of the electromagnetic interaction between the moon’s mini-magnetosphere and the Jovian plasma. Several recent images of Saturn’s auroral regions obtained with Cassini/UVIS at high latitude show an obvious auroral spot at the predicted location of Enceladus’ footprint. This major finding demonstrates that the electromagnetic interaction between a moon and its parent planet is not unique to Jupiter but appears to be a common feature in planetary systems. [less ▲]

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See detailShort-term temperature impacts on soil CO2 fluxes: An incubation experiment with agricultural soil samples.
Buysse, Pauline ULiege; Goffin, Stéphanie ULiege; Carnol, Monique ULiege et al

in Geophysical Research Abstracts (2010, May 06), 12

Detailed reference viewed: 38 (22 ULiège)
See detailMonitoring the ionospheric positioning error with a GNSS dense network
Wautelet, Gilles ULiege; Lejeune, Sandrine; Warnant, René ULiege

Conference (2010, May 06)

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See detailAnnual-scale adaptation of a soil heterotrophic respiration model to three agricultural sites in Belgium and South-Western France.
Buysse, Pauline ULiege; Le Dantec, Valérie; Mordelet, Patrick et al

in Geophysical Research Abstracts (2010, May 06), 12

Detailed reference viewed: 25 (8 ULiège)
See detailLe ralentissement de la progression de l'insuffisance rénale chronique
Krzesinski, Jean-Marie ULiege

Conference (2010, May 06)

Detailed reference viewed: 19 (7 ULiège)
See detailPaleoproductivity and carbon cycling during the Middle Miocene Monterey Excursion
Billups, Katarina; Diester-Haass, Liselotte; Emeis, Kay-Christian et al

Poster (2010, May 06)

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See detailMonitoring a shallow geothermal experiment in a sandy aquifer using electrical resistivity tomography: a feasibility study
Hermans, Thomas ULiege; Vandenbohede, Alexander; Nguyen, Frédéric ULiege et al

Poster (2010, May 06)

Geothermal resources, especially groundwater resources, are increasingly used around the world. It is therefore necessary to improve the characterisation of thermal parameters of the aquifers. This is ... [more ▼]

Geothermal resources, especially groundwater resources, are increasingly used around the world. It is therefore necessary to improve the characterisation of thermal parameters of the aquifers. This is done mostly with thermal response tests. In this work, we monitored with electrical resistivity tomography a geothermal test on the campus of Ghent University (Belgium). We injected warm water (45°C) into a sandy aquifer where the groundwater has a temperature of 10°C at a rate of 100 liter/hour during three days. Laboratory measurements indicated that we could expect at most a change of 2%/°C of the water electrical conductivity. The time-lapse series of electrical images show clearly the thermal plume corresponding to the injected water with a maximum change of minus 20% after 72 hours of injection. A comparison with a geothermal model shows that the anomaly is well detected but also distorded due to the inversion regularization (smoothness constraint). ERT enabled to follow the evolution of the injected heated water with more spatial coverage that traditionnal techniques. ERT is thus an interesting tool to monitor the exploitation of geothermal resources. In the future, it will be necessary to improve the inversion process to use quantitavely such results in a calibration process. [less ▲]

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See detailDual Citizenship and Home-country Voting
Lafleur, Jean-Michel ULiege

Conference (2010, May 05)

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See detailOptimisation of slow-release formulations as biological control devices
Heuskin, Stéphanie ULiege; Lorge, Stéphanie; Debatty-Mestdagh, Michelle et al

Poster (2010, May 05)

E-β-Farnesene, the alarm pheromone of many aphid species and β-caryophyllene, recently identified as one of the possible component of the aggregation pheromones of the Asian ladybeetles Harmonia axyridis ... [more ▼]

E-β-Farnesene, the alarm pheromone of many aphid species and β-caryophyllene, recently identified as one of the possible component of the aggregation pheromones of the Asian ladybeetles Harmonia axyridis Pallas, are considered as two sesquiterpenes attractive for aphids’ predators and parasitoids, Epysirphus balteatus De Geer and Aphidius ervi Haliday, respectively. In the present research, alginate gel beads formulations were optimised as semiochemical slow-release devices. The formulations were evaluated in terms of volatiles release capacity, protection efficiency of sesquiterpenes against oxidation, and biological activity towards Epysirphus balteatus and Aphidius ervi. Moreover, the sesquiterpenes used in the formulations were obtained from natural matrices. Indeed, they were purified by flash chromatography fractionation of essential oils of Matricaria chamomilla L. and Nepeta cataria L., for obtaining E-β-farnesene and β-caryophyllene, respectively. The purities of the fractions were determined by means of a fast GC analytical method optimised for a good resolution of terpenes in less than five minutes. The experiments can conclude that the alginate gel beads formulations are efficient as biological control devices considering the results obtained with the various biological tests led on predators and parasitoids. Moreover, the sesquiterpenes are more protected when formulated in alginate beads than without formulation. The devices allow also a slow-release of semiochemicals during a long time (at least 40 days) depending on physico-chemical parameters (temperature, relative humidity). A mathematical modelisation of semiochemicals release is presently in study. [less ▲]

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See detailQuand c'est l'intension qui compte : opacité référentielle et objectivité
Leclercq, Bruno ULiege

Conference (2010, May 05)

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See detailPheromone variability and evolution in the butterfly genus Bicyclus, and implication in its diversification
Bacquet, Paul; Brattström, O.; Brakefield, P. M. et al

Poster (2010, May 05)

The evolution of olfactive communication in generating reproductive isolation among species remains poorly understood (Smadja & Butlin 2009). In Lepidoptera, studies have mainly focused on long-distance ... [more ▼]

The evolution of olfactive communication in generating reproductive isolation among species remains poorly understood (Smadja & Butlin 2009). In Lepidoptera, studies have mainly focused on long-distance pheromones produced by moths. Moth sex pheromones have been shown to display inter-population variation (e.g. Tòth et al. 1992, McElfresh & Millar 2008 and ref. within, Groot et al. 2009) and to be involved in interspecific isolation (e.g. Löfstedt et al. 1991, Groot et al. 2006). In butterflies, the few existing studies on sex pheromones have mainly focused on the identification of the male specific compounds and the demonstration of their behavioural activity in courtship (e.g. Grula et al. 1980, Nieberding et al. 2008, Yildizhan et al. 2009), but have failed so far to highlight a role in reproductive isolation (Friberg et al. 2008). In the species-rich Bicyclus genus Kirby, 1871 (Nymphalidae, Satyrinae) the structures producing the pheromones, i.e. the androconia, are key characters to discriminate among species (Condamin 1973). In B. anynana (Butler, 1879), the male sex pheromone (MSP) has been shown to play a role in mate choice (Costanzo & Monteiro 2007, Nieberding et al. 2008), to be heritable, and particular ratios of the pheromone components are under strong sexual selection (Nieberding et al, unpubl. data). Therefore, we expect that pheromone evolution is responsible for reproductive isolation and diversification in this butterfly group. In this framework, our research project aims at understanding the evolution of MSP at the interspecific level across the Bicyclus genus and specifically at testing their potential role in the speciation process. Potential MSP of several species across the Bicyclus genus have been identified by gas chromatography and mass spectrometry. Observed differences in pheromone composition between species are compared in a phylogenetic framework to the molecular tree of the species (following Oliver et al. 2009). We expect the evolutionary rate of MSP to be unlinked to the molecular tree if MSP are under sexual selection across the genus (i.e. saltational evolution following Symonds & Elgar 2004, Shirangi et al. 2009). Moreover, if MSP generated reproductive isolation between species in a “reinforcement” process, we expect higher differences of MSP composition between sympatric species than between allopatric species and an increase of this pattern for younger species compared to older species (Lukhtanov et al. 2006). [less ▲]

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See detailEffect of host plants on the abundance of Aphis craccivora Koch (Homoptera : Aphididae) and it parasitism by three parasitoids (Hymenoptera: Braconidae, Pteromalidae, Encyrtidae, ) in green space of Université des Sciences et Techniques de Masuku(USTM, Franceville), Gabon
Poligui, René Noël ULiege; Francis, Frédéric ULiege; Haubruge, Eric ULiege et al

Poster (2010, May 05)

The cow pea aphid, Aphis craccivora Koch were studied on tree wield weeds of lawn (Paspalum sp, Poaceae), Chrysopogon aciculatus (Retz.) Trin. (Poaceae), Sporobolus indicus (L.) R.Br. (Poaceae) and ... [more ▼]

The cow pea aphid, Aphis craccivora Koch were studied on tree wield weeds of lawn (Paspalum sp, Poaceae), Chrysopogon aciculatus (Retz.) Trin. (Poaceae), Sporobolus indicus (L.) R.Br. (Poaceae) and Brachiara decumbens Stapf (Poaceae). 120 infloscences of each host plant specie were examined. The hymenopteran parasitism was based on mummified aphids. In the ascending order of infestation, A.craccivora colonies were less abundant on S.indicus (192 aphids), abundant on C.aciculatus (1546) and highly abundant on B.decumbens (2986). Parasitism on aphids is very low on B.decumbens (7,57%), high on C.aciculatus(57,12%) and very high on S.indicus (82,05%). 410 hymenopteran parasitoids hatch from 500 mummufied aphids taken on S.indicus, for 153 Aphidius sp(Braconidae) individuals ,160 (39,02%) Ceroplastes sp (Pteromalidae) and 97(23, 66%) non identified encyrtid(encyrtidae). Aphidophagous larva of Cheilomenes sulfurea (Coccinelidae) and Platynaspsis capicola Crotch (Coccinellidae) were observed predatoring aphids respectively on C.aciculatus and S.indicus.This study highlight the presence of native beneficials that can be used as biological control agents. [less ▲]

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See detailBiological control device using the aphidophagous hoverfly Episyrphus balteatus (De Geer) (Diptera: Syrphidae)
Leroy, Pascal ULiege; Verheggen, François ULiege; Francis, Frédéric ULiege et al

Poster (2010, May 05)

Augmentative biocontrol constitutes a safe way to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer ... [more ▼]

Augmentative biocontrol constitutes a safe way to reduce pest populations through the enhancement of natural enemies’ activity. In this context, the aphidophagous syrphid Episyrphus baltetaus (De Geer) (Diptera: Syrphidae) is a promising candidate for aphid biological control: larvae of this syrphid attack and consume a wide range of aphid species and are found on many vegetable crops. Because natural populations of beneficials are not always sufficient to regulate the pest infestations, this work has focused on the conception of a biological control device containing syrphid eggs which can easily be introduced in fields or greenhouses. To test and validate the biological control device described above, laboratory and field experiments were performed: a plastic lamella covered with syrphid eggs was suspended on aphid infested plants in order to measure the efficiency of the device. The results obtained were promising since populations of 500 aphids were eliminated in ten days when 15 syrphid eggs were introduced. The use of such a biological control device could certainly contribute to aphid biological control strategies. [less ▲]

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See detailDesign of a decision tool for hydromorphological restoration of water bodies in Walloon Region
Peeters, Alexandre ULiege; Hallot, Eric ULiege; Verniers, Gisèle et al

Poster (2010, May 05)

The pilot project WALPHY (LIFE + Environment LIFE07 ENV/B/000038, UE-funded) develops a structured approach aiming at improving hydromorphological quality of the upstream Meuse basin in order to achieve ... [more ▼]

The pilot project WALPHY (LIFE + Environment LIFE07 ENV/B/000038, UE-funded) develops a structured approach aiming at improving hydromorphological quality of the upstream Meuse basin in order to achieve the “good ecological status” required by the Water Framework Directive (WFD 2000/60). It began in January 2009 for a period of 5 years. River’s biological recovery needs the recovery of river’s structure and physical dynamics. Returning to "good ecological status" inevitably involves physical restoration of affected rivers. Physical component of aquatic environment acts as a limiting factor for their functioning. Three types of modification are key obstacles for river good ecological status: (i) fluxes alteration (discharge, sedimentation. . . ), (ii) forms alteration (uniform facies. . . ) and (iii) biotopes access alteration (lateral connections breaks, modification of the continuity upstream/ downstream. . . ). Therefore hydromorphology is needed to implement the WFD. To respond to this legal necessity, we develop a unique, useful and suitable methodology in Walloon Region to determine and schedule river physical quality restoration works. This methodology has been applied on 3 “risk water bodies”. The works are based on two axes : longitudinal continuity and transversal continuity. The two first selected water bodies (Bocq river, eastern tributary of the Meuse) seem to be convenient for the restoration works which concern the longitudinal continuity due to the presence of dams and other obstacles usually between 1 and 3 m high. These works consist in dam management (weir removal or fish passage) taking into account hydromorphological (bedload transport) and biological (invertebrate or fish species free movement) impacts. The third water bodies (Eau Blanche river, western tributary of the Meuse) presents straightened rivers with artificial banks, witch consequently own bad connections between the stream and its floodplain. This water bodies should therefore be appropriated for the works based on the transversal continuity recovery. They consist in enhancing straightened river channels, restoring meanders or bank restoration. The first river restoration works will take place from summer 2010. A monitoring has already been undertaken to draw up the situation before the restoration works, witch will be able to compare to the situations during and after works. In addition, a natural site has been chosen to enable any comparison with the intervention sites. The geomorphological monitoring is based on physical and sedimentological parameters (substrate cartography, velocity measures, stream channel DEM, topography and sedimentological index). The ecological monitoring consists in analysing the physical and chemical parameters (turbidity, suspended sediment load). It also analyses the biological quality through 3 indicators: macrophytes, macroinvertebrates and fishes. Among other, a microhabitats method has been improved and applied on 3 intervention sites and 1 natural site. The microhabitats cartography results from both the flow velocity cartography and the substrate cartography. With this method, the physical quality of each intervention site could be compared with the natural site and above all with the future situation. Our method is also useful to inventory precisely invertebrates and to characterise fish habitats. [less ▲]

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Peer Reviewed
See detailParticularities of Aphidius ervi embryo development and main limitations of its in vitro culture
Sabri, Ahmed ULiege; Leroy, Pascal ULiege; Hance, Thierry et al

Poster (2010, May 05)

Detailed reference viewed: 145 (36 ULiège)
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See detailHow do insects communicate with a cadaver?
Dekeirsschieter, Jessica ULiege; Verheggen, François ULiege; Frederickx, Christine ULiege et al

Conference (2010, May 05)

Detailed reference viewed: 123 (9 ULiège)
See detailEvolution of Harmonia axyridis (Pallas) alkaloid protection during the year
Fischer, Christophe ULiege; Sibret, Virginie; Laurent, Pascal ULiege et al

Poster (2010, May 05)

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See detailModeling and Finite Element Analysis of Mechanical Behavior of Flexible MEMS Components
Pustan, Marius ULiege; Paquay, Stéphane; Rochus, Véronique ULiege et al

in Courtois, Bernard (Ed.) DTIP 2010 (2010, May 05)

This paper describes the studies of the mechanical characteristics of flexible MEMS components including theoretical approach, finite element analysis and experimental investigations. Modeling and finite ... [more ▼]

This paper describes the studies of the mechanical characteristics of flexible MEMS components including theoretical approach, finite element analysis and experimental investigations. Modeling and finite element analyses together with theoretical and experimental investigations are performed to estimate the mechanical behaviour of MEMS components as microcantilevers, microbridges and micromembranes. The finite element analysis of microcomponents deflections under different loading and the stress distribution in beams is determined and compared with the experimental measurements performed using atomic force microscope. The modeling of a micromembrane supported by four hinges that enable out-of-plane and in-plane motions is presented. Finite element analysis and experimental investigations are performed to estimate the deflection of the mobile plate of the micromembrane under an applied force and to visualize the distribution of the stress in hinges. In additional, this paper provides analytical relations for stiffness and stresses of the investigated flexible MEMS components. [less ▲]

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See detailLong term carbon dioxide exchange above a mixed forest in the Belgian Ardennes: evaluation of different approaches to deduce total ecosystem respiration from Eddy covariance measurements
Jerome, Elisabeth ULiege; Heinesch, Bernard ULiege; Aubinet, Marc ULiege

Poster (2010, May 05)

The general aim of this research is to analyze inter annual variability of carbon dioxide (CO2) fluxes exchanged by a mixed forest located at the Vielsalm experimental site in Belgium. At this site, CO2 ... [more ▼]

The general aim of this research is to analyze inter annual variability of carbon dioxide (CO2) fluxes exchanged by a mixed forest located at the Vielsalm experimental site in Belgium. At this site, CO2 flux measurements started in 1996 and are still going on. Thirteen complete years of measurements are thus available. Net Ecosystem Exchange (NEE) inter annual variability may be driven by gross primary productivity (GPP) or Total Ecosystem Respiration (TER), which should thus be both quantified. Using flux partitioning methods, TER is deduced from NEE measurements. GPP is then obtained by subtracting TER from NEE. Initially, a robust estimation of TER is required. This work seeks to compare two independent approaches to assess TER in order to quantify the implications on inter-annual variability. The comparison was performed on twelve complete years. TER estimates can be deduced by extrapolating to the whole day NEE measurements taken during selected night or day periods. In both case, the extrapolation is performed by using a respiration response to temperature. The first approach, referred as the night-time approach, consisted in calculating TER using a temperature response function derived from night-time data sets (Reichstein et al., 2005). The second approach, referred as the daytime approach, consisted in assessing TER from the intercept of the NEE/Photosynthetically Photon Flux Density (PPFD) response (Wohlfahrt et al., 2005). For each approach, different modalities were compared: the use of long term (annual) or short term (15 days) data sets for the night-time approach and the use of different types of regression for the daytime approach. In addition, the impact of the temperature choice was studied for each of the approaches. For the night-time approach, main results showed that air temperature sensitivity of ecosystem respiration derived from annual data did not reflect the short-term air temperature sensitivity. Vielsalm is a summer active ecosystem (annual temperature sensitivity larger than short-term temperature sensitivity). Results suggested also that, for both approaches, regressions based on soil temperature gave more robust results than those based on air temperature. Furthermore, the comparison showed that the night-time and the daytime approaches give disagreeing pictures of TER inter annual variability which suggested that the choice of the approach is critical in order to correctly depict TER inter annual variability. Finally, at this stage, TER inter annual variability cannot be explained by variability of climatic conditions. [less ▲]

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See detailBiosensors in Forensic Sciences
Frederickx, Christine ULiege; Verheggen, François ULiege; Haubruge, Eric ULiege

Conference (2010, May 05)

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See detailOccurrence of the multicolored ladybird, Harmonia axyridis PALLAS in Walloon agro-ecosystems
Vandereycken, Axel ULiege; Durieux, Delphine ULiege; Joie, Emilie ULiege et al

Conference (2010, May 05)

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations in greenhouses. It took only few years to the insect to get adapted ... [more ▼]

The Asian ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was imported in 1997 in Belgium to control aphid populations in greenhouses. It took only few years to the insect to get adapted to temperate climate conditions and to spread out all over Europe. Now, H. axyridis is one of the coccinellid with the biggest size in Belgium, causing damages to the ecosystems through e.g. intraguild predation (IGP). We are still lacking information about the consequences of the introduction of this superpredator in our agro-ecosystems. This work focuses on the potential impacts of H. axyridis on the entomofauna associated with several crops (potatos, corn, wheat, broad bean). We evaluated in 2009 the occurrence as well as the interactions between aphids and their natural enemies (hoverflies, coccinellids and lacewings) in several agro-ecosystem sites in northern Wallonia. After one year of field observations, were found thirteen coccinellid species, most of the catched individuals being H. axyridis with 64% of the coccinellids, Propylea 14-punctata, 15%, or Coccinella 7-punctata, 14%. This invasive ladybird dominates the group of coccinellids generally in all crops in north Wallonia. The results with the sticky traps show that the maximum occurrence of H. axyridis in crops is observed in chicory, sugar beet and potatoes. The relationship aphid-ladybird in wheat for example, brings out that increase of density of Asian ladybird in mid-July follow the increase of aphids (Sitobion avenae, Sitobion fragariae, Metopolophium dirhodum, Aphis fabae) in the end of June. We also observe that, in most agro-ecosystems, hoverflies and lacewings are the dominant aphid natural enemies. In all crops investigate, the multicolored ladybird occurs with 5% of the aphidophagous after the Chrysopidae, 12% and the Syrphidae, 76%. In 2009, the agro-ecosystems with the most aphidophagous species are carrot and broad bean and these habitats are dominated by hoverflies. [less ▲]

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See detailThe chemical ecology of ladybird beetles
Durieux, Delphine ULiege; Verheggen, François ULiege; Vandereycken, Axel ULiege et al

Conference (2010, May 05)

Ladybird beetles (Coleoptera: Coccinellidae) use a wide variety of semiochemicals to communicate with each other, e.g. finding a mate, protecting themselves from predation or cannibalism, finding a ... [more ▼]

Ladybird beetles (Coleoptera: Coccinellidae) use a wide variety of semiochemicals to communicate with each other, e.g. finding a mate, protecting themselves from predation or cannibalism, finding a shelter to overwinter or ensuring a better survival for their offspring. But chemical communication upon ladybeetles has also found recently to occur with their prey, their prey-host plants and even within their interactions with their natural enemies. Thorough studies on ladybird behaviours towards these compounds could lead to their practical implementation in integrated strategies using ladybirds to control pests, like aphids or mealybugs. [less ▲]

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See detailL’édition littéraire en Belgique au passé et au présent
Durand, Pascal ULiege; Habrand, Tanguy ULiege

Conference (2010, May 05)

Detailed reference viewed: 64 (20 ULiège)