References of "Scientific congresses and symposiums"
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See detailHow the genomic environment of the HTLV-1 provirus impacts on clone fitness
Gillet, Nicolas ULiege; Malani, Nirav; Berry, Charles et al

Conference (2010, May)

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See detailTrajectory Optimization of Flexible Robots Using an Optimal Control Approach
Guimaraes Bastos Junior, Guaraci ULiege; Bruls, Olivier ULiege

in Proceedings of the First Joint International Conference on Multibody System Dynamics (2010, May)

In the context of the mechatronic design of lightweight machines and robots, this paper studies optimal control problems in flexible multibody dynamics. Based on a direct transcription of the initial ... [more ▼]

In the context of the mechatronic design of lightweight machines and robots, this paper studies optimal control problems in flexible multibody dynamics. Based on a direct transcription of the initial problem, a direct collocation method is used. This method leads to a large but sparse nonlinear programming problem for which standard solvers are available. The implemention of this method based on a finite element simulation tool for flexible multibody systems is described. The connections between the generalized-alpha time integration scheme, which is commonly used for this kind of applications, and the formulation of the optimization problem are highlighted. The methodology is illustrated for two academic examples of rigid and flexible robotic systems. [less ▲]

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See detailGenerating informative trajectories by using bounds on the return of control policies
Fonteneau, Raphaël ULiege; Murphy, Susan; Wehenkel, Louis ULiege et al

in Proceedings of the Workshop on Active Learning and Experimental Design 2010 (in conjunction with AISTATS 2010) (2010, May)

We propose new methods for guiding the generation of informative trajectories when solving discrete-time optimal control problems. These methods exploit recently published results that provide ways for ... [more ▼]

We propose new methods for guiding the generation of informative trajectories when solving discrete-time optimal control problems. These methods exploit recently published results that provide ways for computing bounds on the return of control policies from a set of trajectories. [less ▲]

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See detailWillingness-to-pay for local milk-based dairy products in Senegal
Lefevre, Mélanie ULiege

Conference (2010, May)

This paper aims to evaluate Senegalese consumers' willingness-to-pay (WTP) for local fresh milk-based products, in opposition to the ones produced with imported powder. Using data from a choice-based ... [more ▼]

This paper aims to evaluate Senegalese consumers' willingness-to-pay (WTP) for local fresh milk-based products, in opposition to the ones produced with imported powder. Using data from a choice-based-conjoint analysis conducted on 400 households in the region of Dakar, we evaluate the premium that consumers are willing to pay for fresh raw material (rather than powder) in the composition of sour milk. Based on an Ordered Probit Model, the results show evidence for a positive WTP for fresh raw material, which may be seen as a strong indication of preference for local products. This WTP greatly depends on the characteristics of the households. Wealthier households are willing to pay more than the medium households, while big households are ready to pay much less than the base category ones. Obviously, some niche markets exist, that producers may target to sell the local milk-based dairy products. However, more information has to be provided about the composition of dairy products, as consumers are not currently able to distinguish both types of raw material, even if they are willing to pay more for one of them. In spite of some restrictions about the presence of a potential "hypothetical bias" due to the nature of the data, this study gives a first insight of consumers' preferences for local milk-based dairy products. [less ▲]

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See detailEarth and sea-level change projections with the Earth system model of intermediate complexity LOVECLIM
Goelzer, H.; Huybrechts, P.; Loutre, M. F. et al

Conference (2010, May)

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See detailMultiparametric observations and analysis in the Bay of Calvi (Corsica), an ideal site for studying the human activity effects and climate changes in the Mediterranean Sea; STARESO
Gobert, Sylvie ULiege; Alvera Azcarate, Aïda ULiege; Barth, Alexander ULiege et al

Conference (2010, May)

STARESO (Station de REcherche Sous marine et Océanographique) is the marine and oceanographic research station of the University of Liège (Belgium) managed by the French company STARESO S.A.. Constructed ... [more ▼]

STARESO (Station de REcherche Sous marine et Océanographique) is the marine and oceanographic research station of the University of Liège (Belgium) managed by the French company STARESO S.A.. Constructed in 1969, it is located near Calvi (Corsica, Western Mediterranean Sea) in an oligotrophic area chosen for the exceptional quality of its coastal waters STARESO offers to the oceanographers, by diving or with boats, a direct access to the sea. The variety of the accessible ecosystems is remarkable and unique in the Mediterranean basin: -the Bay of Calvi is characterized by healthy and very diverse biocenosis (e.g. Posidonia meadows, rocky and sandy communities, -a steep submarine canyon, with depths greater than 1 000 meters, is accessible in 15 minutes of navigation; -the Liguro-Provençal front, a major hydrologic structure, is situated between 10 and 15 miles of the coast. STARESO is accessible all the year for everybody and is functioning like an oceanographic research vessel. The Station is a platform for all oceanographic disciplines with a scientific expertise widely based on a long tradition of interdisciplinary work, and a direct access to time series of physical, chemical and biological data registered with automated systems and variety of sensors deployed in the Bay of Calvi since 30 years. This platform provides the opportunity to reach coastal, pelagic, benthic, deep systems with a manageable cost and ship requirements in a pristine zone. [less ▲]

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See detailTests de performance NEMA NU1-2001 des cameras TEMP et TEMP/TDM Philips Brightview
Seret, Alain ULiege

in Médecine Nucléaire : Imagerie Fonctionnelle et Métabolique (2010, May), 34(5), 284

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See detailComparaison des objectifs attribués à l’éducation physique en Algérie et en Belgique francophone.
Saker, Tarek; Cloes, Marc ULiege

in Amans-Passaga, Christine; Gal-Petitfaux, Nathalie; Terral, Philippe (Eds.) et al L’intervention en sport et ses contextes institutionnels : cultures et singularité de l’action (2010, May)

Cette étude se base essentiellement sur le concept de la représentation de l'éducation physique et de ses objectifs. Dans les pays occidentaux, cette discipline scolaire est généralement bien appréciée ... [more ▼]

Cette étude se base essentiellement sur le concept de la représentation de l'éducation physique et de ses objectifs. Dans les pays occidentaux, cette discipline scolaire est généralement bien appréciée par les élèves. Il s'avère intéressant de vérifier si cette situation est influencée par des aspects culturels et, ainsi déterminer si les acteurs de la relation didactique développent d'autres représentations dans le monde arabe. [less ▲]

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See detailLes inventaires forestiers par échantillonnage comme outil d’aide à la gestion : exemple d’application au Domaine royal de Ciergnon
Gheysen, Thibaut ULiege; Arnould, Dominique; Nachtergaele, Quentin et al

Poster (2010, May)

Ce poster présente un exemple concret de mise en oeuvre d’inventaire forestier de gestion sur un massif d’environ 5000 ha de forêt situé en Wallonie. L’objectif est de fournir au gestionnaire un tableau ... [more ▼]

Ce poster présente un exemple concret de mise en oeuvre d’inventaire forestier de gestion sur un massif d’environ 5000 ha de forêt situé en Wallonie. L’objectif est de fournir au gestionnaire un tableau de bord rassemblant les principaux indicateurs décrivant l’état de son patrimoine forestier. Le plan d’échantillonnage est constitué d’une grille systématique comportant 1 point de sondage par 4 ha. Les points sont permanents et visités tous les 4 ans. Les informations, délivrées dans un rapport d’inventaire standardisé, concernent notamment : la surface terrière et le volume par ha, la structure, la composition, l’état de la régénération, le potentiel biomasse, la diversité spécifique et les accroissements. [less ▲]

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See detailPre-study of the hydraulic works for the Seine-Scheldt-East Project
Rigo, Philippe ULiege; Herbillon, Vincent ULiege; Buldgen, L. et al

in 32nd PIANC Congress – Liverpool UK – 10-14 May 2010 (2010, May)

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See detailInnovations in Navigation Lock Design
Rigo, Philippe ULiege; Members of PIANC INCOM WG29

in 32nd PIANC Congress – Liverpool UK – 10-14 May 2010 (2010, May)

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See detailGRANDS TRAVAUX D’AMENAGEMENT ET MOUVEMENTS DE VERSANT. LE CAS DE TAFFRENT( CONSTANTINOIS, ALGERIE)
Benabbas, Chaouki; Chabour, Nabil; Bourefis, Ahcéne et al

Conference (2010, May)

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See detailUpper confidence bound based decision making strategies and dynamic spectrum access
jouini, wassim; Ernst, Damien ULiege; Moy, Christophe et al

in Proceedings of the 2010 IEEE International Conference on Communications (2010, May)

In this paper, we consider the problem of exploiting spectrum resources for a secondary user (SU) of a wireless communication network. We suggest that Upper Confidence Bound (UCB) algorithms could be ... [more ▼]

In this paper, we consider the problem of exploiting spectrum resources for a secondary user (SU) of a wireless communication network. We suggest that Upper Confidence Bound (UCB) algorithms could be useful to design decision making strategies for SUs to exploit intelligently the spectrum resources based on their past observations. The algorithms use an index that provides an optimistic estimation of the availability of the resources to the SU. The suggestion is supported by some experimental results carried out on a specific dynamic spectrum access (DSA) framework. [less ▲]

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See detailInventaire sur l’affectation des terres de la Belgique dans le cadre du Protocole de Kyoto et de la CCNUCC
Bauwens, Sébastien ULiege; Hebert, Jacques ULiege; Lejeune, Philippe ULiege

Poster (2010, May)

La Belgique réalise annuellement un inventaire de ses émissions de gaz à effet de serre (GES) dans le cadre du Protocole de Kyoto et de la Convention Cadre des Nations Unies sur les Changements ... [more ▼]

La Belgique réalise annuellement un inventaire de ses émissions de gaz à effet de serre (GES) dans le cadre du Protocole de Kyoto et de la Convention Cadre des Nations Unies sur les Changements Climatiques (CCNUCC/UNFCCC). L’affectation des terres et le changement d’affectation des terres (LULUCF) forment l’un des cinq principaux secteurs qui doivent être rapportés dans cet inventaire national. Ce poster présente la méthode mise en œuvre au niveau de la Belgique pour réaliser le rapportage de ce secteur, ainsi que les résultats pour 1990 et 2008. [less ▲]

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See detailOntogeny of sex differences in steroid-sensitive regions in the quail brain (Coturnix Japonica)
Mouriec, Karen ULiege; Bardet, Sylvia; Balthazart, Jacques ULiege

Poster (2010, May)

Sex differences affecting the expression of sexual behavior are observed in many species. In quail, expression of the male-typical copulatory pattern is androgen-dependent. This behavior disappears within ... [more ▼]

Sex differences affecting the expression of sexual behavior are observed in many species. In quail, expression of the male-typical copulatory pattern is androgen-dependent. This behavior disappears within a week after castration and is restored after a few days of treatment with exogenous testosterone. In contrast, ovariectomized females treated with testosterone never show the sequence of male-typical copulatory behavior. This sex difference in responsiveness to testosterone results from organizational effects of embryonic estrogens secreted by the female ovary. The behavioral phenotype can be completely reversed by treatment, before embryonic day 12, of male embryos with estrogens or of female embryos with an aromatase inhibitor. In the quail brain, the medial preoptic nucleus (POM) is a necessary and sufficient site for the activation by testosterone of sexual behavior. Aromatase, the enzyme converting testosterone into estradiol, is densely expressed in POM and its activity is sexually differentiated (males>females) even when birds are treated with a same dose of testosterone. Aromatase and other neuroendocrine systems are thus, like sexual behavior, differentially activated by testosterone in adult quail but the cellular basis of these sexually differentiated features presumably organized in early life by steroid action have not been identified. To analyze the ontogeny of steroid sensitive regions that control behavioral sex differences in the quail brain, we injected 5-bromo-2-deoxyuridine (BrdU) in eggs at different stages of the embryonic (E) development (E8, E10, E12, E14 and E16) and sacrificed the animals at postnatal (PN) day 56. Large numbers of BrdU-positive cells were observed throughout the POM of males and females injected on E8-E10 but most cells were post-mitotic in both sexes on E14-E16. E12 injections resulted in a larger number of BrdU cells in females than in males. This differential number of BrdU-positive cells seen at PN56 in birds injected on E12 could result from a) a difference in the age at which cells become post-mitotic (males before females or alternatively females before males, so that male cells labeled by BrdU on E12 dilute their label in subsequent divisions) or b) a differential apoptosis between E13 and PN56. However, no sex differences in the number of BrdU positive cells was observed in embryos injected with BrdU on E12 and killed on E13. Furthermore, BrdU injections on E14 labeled very few cells at PN 56 suggesting that the POM is essentially post-mitotic at that age. The sex difference observed in birds injected at E12 should result from a differential apoptosis after E13. Double-label immunohistochemistry for BrdU and the neuronal marker Hu (C/D) indicated that all BrdU-positive cells born between E8 and E16 are not neurons (no double label) suggesting that these are glial cells. This sex difference in (glial?) proliferation around the end of the critical period of sexual differentiation may play a key role in the differentiation of brain and behavior. The specific phenotype of these cells and the mechanisms mediating their differential development are currently under investigation. [less ▲]

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See detailModel-free Monte Carlo-like policy evaluation
Fonteneau, Raphaël ULiege; Murphy, Susan; Wehenkel, Louis ULiege et al

in Proceedings of the Thirteenth International Conference on Artificial Intelligence and Statistics (AISTATS 2010) (2010, May)

We propose an algorithm for estimating the finite-horizon expected return of a closed loop control policy from an a priori given (off-policy) sample of one-step transitions. It averages cumulated rewards ... [more ▼]

We propose an algorithm for estimating the finite-horizon expected return of a closed loop control policy from an a priori given (off-policy) sample of one-step transitions. It averages cumulated rewards along a set of “broken trajectories” made of one-step transitions selected from the sample on the basis of the control policy. Under some Lipschitz continuity assumptions on the system dynamics, reward function and control policy, we provide bounds on the bias and variance of the estimator that depend only on the Lipschitz constants, on the number of broken trajectories used in the estimator, and on the sparsity of the sample of one-step transitions. [less ▲]

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See detailValidation du système d’analyse de match AMISCO(TM) : une étude préliminaire
Rodriguez de la Cruz, Carlos ULiege; Croisier, Jean-Louis ULiege; Bury, Thierry ULiege

in Actes du 5ème Colloque international "Football et recherche - technologie et performance" (2010, May)

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See detailModel-free Monte Carlo–like policy evaluation
Fonteneau, Raphaël ULiege; Murphy, Susan; Wehenkel, Louis ULiege et al

in Proceedings of Conférence Francophone sur l'Apprentissage Automatique (CAp) 2010 (2010, May)

We propose an algorithm for estimating the finite-horizon expected return of a closed loop control policy from an a priori given (off-policy) sample of one-step transitions. It averages cumulated rewards ... [more ▼]

We propose an algorithm for estimating the finite-horizon expected return of a closed loop control policy from an a priori given (off-policy) sample of one-step transitions. It averages cumulated rewards along a set of “broken trajectories” made of one-step transitions selected from the sample on the basis of the control policy. Under some Lipschitz continuity assumptions on the system dynamics, reward function and control policy, we provide bounds on the bias and variance of the estimator that depend only on the Lipschitz constants, on the number of broken trajectories used in the estimator, and on the sparsity of the sample of one-step transitions. [less ▲]

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See detailPenser la justice en contextes islamiques
Nachi, Mohamed ULiege

Conference (2010, May)

Inscrire la question de la justice dans les contextes des sociétés islamiques pour en montrer la spécificités et les différentes dimensions sociales, culturelles, politiques, éthiques, etc.

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See detailInfluence of contact resistance on shielding efficiency of shielding gutters for HV cables
Koruglu, Selim; Sergeant, Peter; V Sabariego, Ruth ULiege et al

in Proceedings of the 14th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC2010) (2010, May)

Shielding of buried three phase high voltage cables can be done by placing the cables in conducting ferromagnetic U- shaped gutters covered by plates. In case of a perfect electrical contact between ... [more ▼]

Shielding of buried three phase high voltage cables can be done by placing the cables in conducting ferromagnetic U- shaped gutters covered by plates. In case of a perfect electrical contact between adjacent gutters and between adjacent cover plates, the induced currents in the shield efficiently reduce the field generated in the vicinity of the cables. However, as a perfect contact cannot be guaranteed, it is useful to quantify the effect of a bad electrical contact on the shielding performance. From 2D FEM, 3D FEM and experiments, it is observed that a bad contact does not influence significantly the shielding if the axial length of the plates is relatively long compared to their other dimensions. [less ▲]

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See detailL'enlèvement international d'enfants- questions choisies
Pfeiff, Silvia ULiege

Conference (2010, May)

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See detailMicrowave – assisted synthesis of carbohydrate compounds, focus on uronic acid derivatives.
Laurent, Pascal ULiege; Richel, Aurore ULiege; Wathelet, Bernard ULiege et al

Poster (2010, May)

At the moment, biorefining is increasingly seen as a promising alternative to petrochemical sector since it targets both the replacement of part of petroleum as a source of energy and the development of ... [more ▼]

At the moment, biorefining is increasingly seen as a promising alternative to petrochemical sector since it targets both the replacement of part of petroleum as a source of energy and the development of chemicals from the biomass, such as detergents, phytopharmaceutics, solvents, plastics, etc. The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks is therefore an area of outmost interest. In this context, uronic acids such as glucuronic acid (GlcA) or galacturonic acid (GalA) derived from widely available raw material such as hemicellulose or pectins represent important biocompatible and bioresorbable starting material. The quest of highly effective, environmentally friendly and straightforward chemical strategies to transform totally O-unprotected uronic acids into high valuable materials remains actually a particularly challenging task. A new strategy enabling the quantitative “one-pot” production of water-soluble monosubstituted D-glucofuranosidurono-6,3-lactones from unprotected D-glucuronic acid (D-GlcA) involving microwaves and an inexpensive siliceous-based promoter will be described. The use of a heterogeneous acid catalytic systems consisting of sulfuric acid impregnated onto silica (H2SO4/SiG60) or onto carbon (H2SO4/C), offers a green alternative to unrecyclable liquid sulfuric acid and permit the developpment of a truly eco-friendly green process, as these supported acids were readily separated from liquid products, without neutralization, by decantation or filtration, thus minimizing energy consumption and wastes. Faced with environmental concerns, this solventless methodology offers attractive features, including short reaction times, high yields and easy set-up and workup. [less ▲]

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See detailA model reduction algorithm for solving multiple scattering problems using iterative methods
Vion, Alexandre ULiege; V Sabariego, Ruth ULiege; Geuzaine, Christophe ULiege

in Proceedings of the 14th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC2010) (2010, May)

This paper presents a new method for solving scattering problems by multiple objects. A model reduction algorithm based on the Macro Basis Functions (MBFs) method is used to find an approximate solution ... [more ▼]

This paper presents a new method for solving scattering problems by multiple objects. A model reduction algorithm based on the Macro Basis Functions (MBFs) method is used to find an approximate solution within a subspace of solutions, that are the solutions of several single scattering subproblems. Different iterative methods for the generation of the MBFs are compared. The whole process relies on a finite element approach and is applied to convex obstacles scattering. [less ▲]

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See detailOptimizing team members communication skills in radiation oncology : content and feasibility of a Belgian Interuniversity Curriculum
Caps, E.; Etienne, Anne-Marie ULiege; Bragard, Isabelle ULiege et al

in Psycho-oncology (2010, May), 19(Suppl.2)(1-313), 254

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See detailFailure patterns amongst small firms and their financial symptoms : A test of hypotheses
Crutzen, Nathalie ULiege; Van Caillie, Didier ULiege

in Proceedings of the 33rd Annual Congress of the European Accounting Asssociation (2010, May)

Financial indicators have been widely used in the business failure literature in order to predict the risk of failure of firms (Beaver, 1966; Altman, 1968; Barnes, 1987; Aziz et al., 1988). In contrast ... [more ▼]

Financial indicators have been widely used in the business failure literature in order to predict the risk of failure of firms (Beaver, 1966; Altman, 1968; Barnes, 1987; Aziz et al., 1988). In contrast, financial ratios have been less commonly used in a more preventive perspective to failure (Van Wymeersch and Wolfs, 1996; Van Caillie, 2000; Balcaen and Ooghe, 2006). Nevertheless, in a preventive perspective to small business failure, it is important to better understand how financial symptoms combine over time (Ooghe and Van Wymeersch, 1986) and to identify if relationships can be traced between the fundamental causes of failure and specific financial indicators. Considering this last statement and with reference to the explanatory business failure patterns (EBFPs) identified by Crutzen (2009) amongst a sample of small firms, this paper tests a series of hypotheses which aim at determining if these (causal) patterns can be associated with some specific financial indicators and, if so, if small distressed firms can be associated to one particular EBFP on the basis of the financial information published in the annual accounts. If each EBFP leads to some specific financial symptoms, then it will be possible to get a proxy information about the fundamental problems inducing failure without having any access to internal information, this identification being considered as a crucial step in the elaboration of any recovery or takeover plan (Argenti, 1976; Gaskill et al., 1993). [less ▲]

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See detailIdentification des objectifs et finalités de la formation des diplômés en éducation physique. Comparaison des situations algérienne et belge francophone
Kerfes, Nabil; Cloes, Marc ULiege

in Amans-assaga, Christine; Gal-Petitfaux, Nathalie; Terral, Philippe (Eds.) et al L'intervention en sport et ses contextes institutionnels: cultures et singularité de l'action (2010, May)

Toute formation supérieure a ses principes et ses particularités visant à développer des compétences en relation avec les finalités professionnelles disponibles. La formation des éducateurs est l'une des ... [more ▼]

Toute formation supérieure a ses principes et ses particularités visant à développer des compétences en relation avec les finalités professionnelles disponibles. La formation des éducateurs est l'une des préoccupations majeures de toutes les sociétés cherchant le progrès et le développement. Ce travail se situe dans le champ de l'éducation comparée, il propose une lecture compréhensive de deux systèmes de formation dans un esprit d'ouverture et d'élargissement des connaissances. ... [less ▲]

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See detailUpdating hydrogen fluoride (HF) FTIR time series above Jungfraujoch: comparison of two retrieval algorithms and impact of line shape models
Duchatelet, Pierre ULiege; Demoulin, Philippe ULiege; Hase, Frank et al

Poster (2010, May)

Fluorine enters the stratosphere mainly in the form of chlorofluorocarbons (CFCs; principally CFC-11 and CFC-12) and tetrafluoromethane (CF4), which have been widely emitted at ground level by human ... [more ▼]

Fluorine enters the stratosphere mainly in the form of chlorofluorocarbons (CFCs; principally CFC-11 and CFC-12) and tetrafluoromethane (CF4), which have been widely emitted at ground level by human activities over the past few decades. In the lower stratosphere, the photolysis of the long-lived CFC-11 (CCl3F) and CFC-12 (CCl2F2), whose emissions from the ground have been progressively phased out by the Montreal Protocol and its successive Amendments and Adjustments, leads to the formation of the two reservoirs: COClF and COF2. Subsequent photolysis of these two compounds then liberates F atoms, which could quickly react with CH4, H2O or H2 to form the extreme stable hydrogen fluoride (HF) gas. The formation of HF by these reactions is significant, as they make HF the largest fluorine reservoir in the middle and upper stratosphere. Despite the fact that fluorine does not directly participate in ozone depletion, measurements of the concentration of individual F-containing species at different altitude of the atmosphere are important as they reflect the amounts of anthropogenic gases – which also often bear ozone-threatening Cl atoms - transported into the middle atmosphere as well as their decomposition. Since the first detection of hydrogen fluoride in the Earth’s atmosphere by Zander (1975), several studies dealing with HF total column amounts derived from ground-based Fourier transform infrared (FTIR) observations at several latitudes in both hemispheres have been published. In addition, these last years have seen the emergence of more sophisticated retrieval algorithms (e.g. SFIT-2, PROFFIT) allowing to inverse total or partial columns as well as vertical distribution of the target gas from ground-based FTIR spectra. In this contribution, we propose to compare HF total columns derived from FTIR high-resolution ground-based observations performed at the Jungfraujoch (46.5°N, 8.0°E, 3580 m asl) by using two different retrieval codes: SFIT-2 v.3.91 and PROFFIT v.9.5. The impact of spectroscopic parameters (Voigt line shape model versus Galatry model line shape) on HF retrievals is also analyzed. References: Zander, R.: Présence de HF dans la stratosphère supérieure, C.R. Acad. Sci. Paris. Série B., 281, 213-214, 1975. [less ▲]

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See detailThe impact of nutrition on bone health
Reginster, Jean-Yves ULiege; De Vriese, S.

in Osteoporosis International (2010, May), 21(Suppl.1), 389

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See detailVOC emissions from a temperate mixed forest in Belgium measured by eddy-covariance
Laffineur, Quentin ULiege; Heinesch, Bernard ULiege; Aubinet, Marc ULiege et al

Poster (2010, May)

Forest ecosystems are known to be important emitters of Biogenic Volatile Organic Compounds (BVOC). They play an important role in the atmospheric chemistry and may contribute to the formation of ozone ... [more ▼]

Forest ecosystems are known to be important emitters of Biogenic Volatile Organic Compounds (BVOC). They play an important role in the atmospheric chemistry and may contribute to the formation of ozone and aerosols with consequences on air quality and on climate. In order to better understand the effects of environmental parameters on the emissions, micrometeorological flux measurements were carried out above a mixed forest (Fagus sylvatica, Pseudotsuga menziesii, Abies alba, Picea abies) at the Vielsalm experimental site (Belgium) from July to November 2009. The flux measurements were obtained by the eddy-covariance technique using proton transfer reaction mass spectrometry. In our first measurement campaign, among other VOC compounds, isoprene (m/z 69) and monoterpenoid compounds (m/z 137) have been measured continuously with a data coverage of 75 and 58 % respectively, allowing robust statistical analysis. In our analysis, we focused on these two main emissions. A footprint analysis showed that Fagus sylvatica seems to be the main emitter of m/z 137 and Abies alba seems to be the main emitter of m/z 69. BVOCs fluxes present an exponential response to temperature. This response is more pronounced for m/z 69 while it shows the strongest seasonal evolution for m/z 137. A light dependence of m/z 69 and m/z 137 fluxes was observed but the relationship did not exhibit the same behaviour before (hyperbolic relation) and after midday (linear relation). This behaviour difference induced a hysteresis effect on the daily evolution of averaged fluxes. A robust local minimum was also observed just before midday for m/z 69 (less obvious for m/z 137) during July-August period. This minimum is not observed in the CO2 fluxes which are also measured in Vielsalm. The light dependence of BVOC emissions suggests that m/z 69 and m/z 137 emissions are directly linked to the photosynthetic cycle but the presence of the midday local minimum suggests that other processes influence the measured BVOC fluxes. As for the relation with air temperature, a seasonal evolution of flux-light dependence was far more evident for m/z 137 than for m/z 69. This seasonal variation could be explained by a phenological effect. As Fagus sylvatica is the main m/z 137 emitter, its flux is probably influenced by leaves ageing while m/z 69, as mainly emitted by Abies alba, is less influenced by needles ageing. A wind speed dependence of BVOCs fluxes was also observed, the flux increasing linearly with wind speed. This surprising result will be discussed. [less ▲]

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See detailPerception, par les parents, des effets d’un programme expérimental consistant à doubler le nombre d’heures d’éducation physique dans l’enseignement primaire.
Derome, Stéphane; Cloes, Marc ULiege

in Amans-Passaga, Christine; Gal-Petitfaux, Nathalie; Terral, Philippe (Eds.) et al L’intervention en sport et ses contextes institutionnels : cultures et singularité de l’action (2010, May)

Un projet expérimental consistant à doubler le nombre de séances d'éducation physique a été mis en oeuvre dans 10 écoles primaires de la Communauté française de Belgique. Les avis des parents quant aux ... [more ▼]

Un projet expérimental consistant à doubler le nombre de séances d'éducation physique a été mis en oeuvre dans 10 écoles primaires de la Communauté française de Belgique. Les avis des parents quant aux attitudes et comportements de leurs enfants ont été analysés, de même que leurs opinions au sujet du déroulement des activités. Il apparait qu'une très large majorité des personnes interrogées sont très favorables au programme et considèrent que les enfants bénéficient d'effets positifs, notamment au niveau de l'attitude à l'égard de l'école et du travail scolaire. [less ▲]

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See detailCombining Surface Impedance Boundary Conditions with Volume Discretisation in Time-Domain Finite-Element Modeling
Gyselinck, Johan; Dular, Patrick ULiege; Geuzaine, Christophe ULiege et al

in Proceedings of the 14th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC2010) (2010, May)

In this paper a hybrid approach for considering massive conducting regions in time-domain finite-element modeling is presented. Surface impedance boundary conditions, developed in the time domain as ... [more ▼]

In this paper a hybrid approach for considering massive conducting regions in time-domain finite-element modeling is presented. Surface impedance boundary conditions, developed in the time domain as previously proposed by the authors, are adopted so as to allow for high-frequency flux components (in a certain frequency band) without the need for very fine discretisation of the conducting region near its surface. These surface conditions are combined with a coarse FE mesh inside the region for conveying slowly varying flux components. The correct impedance behaviour can thus be obtained in a wide frequency range, from DC flux on. The approach is briefly demonstrated by means of a simple 1D test case. [less ▲]

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See detailA FRAX® model for the assessment of fracture probability in Belgium
Neuprez, Audrey ULiege; Johansson, H.; Kanis, J. et al

in Osteoporosis International (2010, May), 21(Suppl.1), 255

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See detailAnalyzing and Reducing Error in 2-D Frequency Domain Homogenization of Windings for R, L Parameters FE Computation
De Grève, Zacharie; Deblecker, Olivier; Lobry, Jacques et al

in Proceedings of the 14th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC2010) (2010, May)

In this work, the error made by frequency domain homogenization of windings in 2-D magnetodynamics is quantified. To that end, the homogenized fields are combined with the analytical solutions (a) of eddy ... [more ▼]

In this work, the error made by frequency domain homogenization of windings in 2-D magnetodynamics is quantified. To that end, the homogenized fields are combined with the analytical solutions (a) of eddy currents flowing in a circular conductor placed in a uniform alternating magnetic induction (proximity effect) and (b) of current density in conductors with non-zero net current (skin effect). They are then compared to the fields from the fine model, taken as reference. It is shown that error on resistance can reach 10\% at high frequencies for magnetic components with a limited number of turns. Procedures to improve winding R, L parameters estimation from homogenized solution are introduced. [less ▲]

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See detailHealth-related quality of life after total knee or hip replacement : a 7-year prospective study
Bruyère, Olivier ULiege; Vanoverberghe, Marie ULiege; Neuprez, Audrey ULiege et al

in Osteoporosis International (2010, May), 21(Suppl.1), 26

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See detailGlass production in Merovingian time
Van Wersch, Line ULiege; Mathis, François ULiege; Othmane, G. et al

Poster (2010, May)

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See detailNumerical solution of DAEs in flexible multibody dynamics using Lie group time integrators
Bruls, Olivier ULiege; Cardona, Alberto; Arnold, Martin

in Proceedings of the First Joint International Conference on Multibody System Dynamics (2010, May)

This paper studies a family of Lie group time integrators for the simulation of flexible multibody systems. The method provides an elegant solution to the rotation parameterization problem and, as an ... [more ▼]

This paper studies a family of Lie group time integrators for the simulation of flexible multibody systems. The method provides an elegant solution to the rotation parameterization problem and, as an extension of the classical generalized-alpha method for dynamic systems, it can deal with constrained equations of motion. Here, second-order accuracy of the Lie group method is demonstrated for constrained problems. The convergence analysis explicitly accounts for the nonlinear geometric structure of the Lie group. The performance is illustrated on two critical benchmarks of rigid and flexible systems with large rotation amplitudes. Second-order accuracy is evidenced in both of them. The remarkable simplicity of the new algorithms opens some interesting perspectives for real-time applications, model-based control and optimization of multibody systems. [less ▲]

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See detailComparaison des méthodes de Lord et de la régression logistique pour la détection du fonctionnement différentiel des items
Raîche, Gilles; Magis, David ULiege; Béland, Sébastien

Conference (2010, May)

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See detailÉtude du fonctionnement différentiel d’items selon plusieurs groupes focaux : une analyse du test d’anglais-langue seconde (TCALS-II) entre 1998 et 2008
Béland, Sébastien; Croisetière, Catherine; Magis, David ULiege et al

Conference (2010, May)

Detailed reference viewed: 67 (3 ULiège)
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See detailStudy of the role of miR-21 in the regulation of angiogenesis
Sabatel, Céline; Malvaux, Ludovic; Bovy, Nicolas ULiege et al

Poster (2010, May)

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See detailUne intentionnalité grammaticale chez Wittgenstein
Gauvry, Charlotte ULiege

Conference (2010, May)

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See detailComment développer le portfolio étudiant au supérieur ? Analyse de dispositifs innovants à l’Université de Liège
Deum, Mélanie ULiege; Gruslin, Isabelle ULiege; Peters, Stéphanie ULiege et al

Conference (2010, May)

Depuis 2008, l’Institut de Formation et de Recherche en Enseignement Supérieur de l’Université de Liège (IFRES) accompagne des innovations pédagogiques qui consistent, notamment, en l’implantation de ... [more ▼]

Depuis 2008, l’Institut de Formation et de Recherche en Enseignement Supérieur de l’Université de Liège (IFRES) accompagne des innovations pédagogiques qui consistent, notamment, en l’implantation de portfolios pour des étudiants de master. Ces initiatives, venant de quatre équipes d’enseignants-chercheurs (Psychologie sociale des groupes et des organisations, Formation d’adultes, Pharmacie et Logopédie), poursuivent des objectifs centrés sur l’articulation théorie-pratique, l’accompagnement de démarches réflexives, le développement et l’évaluation de compétences. Notre communication se focalisera principalement sur la mise en œuvre de ces initiatives au travers des questions suivantes : Comment intégrer un portfolio étudiant dans le cadre d’une formation universitaire? Comment en évaluer son contenu? Comment accompagner les étudiants dans la collecte de preuves significatives ? Des perspectives concernant l’accompagnement de tels projets pédagogiques seront également abordées pour qu’au delà de l’analyse de quelques dispositifs portfolio, notre communication apporte un regard plus critique sur les conditions optimales d’implantation et d’accompagnement d’innovations pédagogiques telles que la mise en place d’un portfolio pour les étudiants. [less ▲]

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See detailIntentionnalité et intentionnalisme chez Brentano
Boccaccini, Federico ULiege

Conference (2010, May)

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See detailComparison of the error budgets associated with ground-based FTIR measurements of atmospheric CH4 profiles at Ile de la Réunion and Jungfraujoch
Vanhaelewyn, Gauthier; Duchatelet, Pierre ULiege; Vigouroux, Corinne et al

Poster (2010, May)

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See detailHow to construct fundamental risk factors?
Lambert, Marie ULiege; Hübner, Georges ULiege

Conference (2010, May)

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See detailEfficient access pricing and endogenous market structure
Gautier, Axel ULiege

Poster (2010, May)

We investigate how a regulatory mechanism can influence the nature of competition in a network industry. In the downstream market, the seller of a differentiated retail product competes with an incumbent ... [more ▼]

We investigate how a regulatory mechanism can influence the nature of competition in a network industry. In the downstream market, the seller of a differentiated retail product competes with an incumbent firm. The incumbent firm is also the owner of the essential input. The regulator may or may not observe the cost of the entrant. To maximize social welfare the regulator specifies the access charge that the entrant must pay to the incumbent, and the retail prices. The optimal access charge is a uniform price that respects the criteria of transparency and non-discrimination that are imposed by the competition and regulation directives in most countries. We derive new formulas for retail and access prices adhering to the traditional Ramsey rule. Since the competing firm takes the decision to enter following the choice of the regulatory regime, the nature of the retail market competition is endogenous [less ▲]

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See detailOn the Convergence of Social Protection Performance in the European Union
Lefebvre, Mathieu ULiege

Conference (2010, May)

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See detailUN NOUVEAU SYNDROME HÉMORRAGIQUE INEXPLIQUÉ CHEZ LE BOVIN – LA PANCYTOPÉNIE NÉONATALE BOVINE
Theron, Léonard ULiege; Vogin, Nathalie; Moreaux, Emeline et al

in Antibiothérapies : Santé animale et santé publique (2010, May)

For several decades, the bovine was subject to various hemorrhagic syndromes which causes have historically been found. Since the mid-2000s, a new hemorrhagic syndrome seems to emerge with a significant ... [more ▼]

For several decades, the bovine was subject to various hemorrhagic syndromes which causes have historically been found. Since the mid-2000s, a new hemorrhagic syndrome seems to emerge with a significant epidemiological consistency, suggesting a common etiology, although unknown at present. The affected animals were calves of less than 30 days, of all races born to mothers without specific parity. We noticed a very sporadic disease (1/10.000) but lethal to 99%. The characteristic lesions are multifocal hemorrhages, hyperthermia, melena, we noted medullar aplasia systematically. These calves are vironegative for BTV, enzootic bovine leukosis and BVDV. No viral or bacterial agent could be isolated. It seems that most of these calves were born from dams vaccinated against BVDV. The track of an immune dysfunction is the most serious for the moment. [less ▲]

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See detailAir-ice CO2 fluxes and pCO2 dynamics in sea ice in the Arctic coastal area (Amundsen Gulf, Canada)
Geilfus, Nicolas-Xavier ULiege; Tison, Jean Louis; Carnat, Gauthier et al

Conference (2010, May)

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See detailAPPROCHE DICHOTOMIQUE DE LA BACTÉRIOLOGIE DES MAMMITES - UNE AIDE À LA PRISE DE DÉCISION THÉRAPEUTIQUE AU CHEVET DU PATIENT
Theron, Léonard ULiege; Hanzen, Christian ULiege

in Antibiothérapies : Santé animale et santé publique (2010, May)

In France and Belgium, 50 to 100 % of all dairy animals receive at least an intramammary antibiotic treatment for bovine mastitis during lactation. Yet, results of bacteriology reveal a lack of growth in ... [more ▼]

In France and Belgium, 50 to 100 % of all dairy animals receive at least an intramammary antibiotic treatment for bovine mastitis during lactation. Yet, results of bacteriology reveal a lack of growth in more than one third of the cases, also Escherichia coli accounts for 17% of the three germs mostly identified. Several recent authors support management of infections with E. coli in lactation without any antibiotic. Given these facts, the question of antibiotics use for mastitis may be highlighted. To do this, simplified bacteriology devices, such as Petrifilm®, can be used to develop a dichotomous strategy guided by the veterinarian on a treatment plan that excludes the routine use of antibiotics on E. coli and negative growth. The principle is growing on a plate for non-selective aerobic germ, a selective plate for E. coli and a selective plate for staphylococci. This strategy may be conducted by the producer, in consultation with his veterinarian, to minimize the risk of emergence of an atypical germ. [less ▲]

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See detailAbscisic acid signal transduction is altered in Arabidopsis plants deficient in plastidial glyceraldehyde- 3-phosphate dehydrogenase
Muñoz-Bertomeu, Jesús; Cascales - Miñana, Borja ULiege; Anoman, Armand D. et al

Conference (2010, May)

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See detailRankine cycle for waste heat recovery on commercial trucks: approach, constraints and modelling
Espinosa, Nicolas; Tilman, Loic; Lemort, Vincent ULiege et al

(2010, May)

With increasing oil price and growing interest in cutting green house gases emissions, waste heat recovery techniques appear as a very promising path to enhance engine thermal efficiency ... [more ▼]

With increasing oil price and growing interest in cutting green house gases emissions, waste heat recovery techniques appear as a very promising path to enhance engine thermal efficiency. Thermoelectricity and Rankine cycles are two possible ways to recover thermal energy. The Rankine cycle shows the highest potential due to its higher cycle efficiency in comparison with the current state-of-the-art thermoelectric materials intrinsic conversion ratio. This paper will focus on the Rankine cycle system. The first part of the paper lists and describes the constraints of a heat recovery Rankine cycle system associated to a long haulage truck: limitation of heat available in the heat source, vehicle heat rejection constraints, safety and environmental issues for the working fluid, and backpressures occurring during the heat recovery process. The second part of the paper presents a 0-D simulation model of a Rankine cycle system. It is shown how the model can be used to compare the performance achieved with several working fluids. Moreover, basic thermodynamic limitations of the system are underlined. Conclusions are drawn concerning the limitation of using only thermodynamic simulations. The performance of the condenser (and its influence on the overall performance) has been investigated more in details, which is shown in the third part of the paper. This was carried out based on a 1-D simulation model of the condenser. Influence of the condenser size and ram air effect are discussed, and the impact on the Rankine cycle is assessed. [less ▲]

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See detailEffects of arzoxifene on fracture incidence in postmenopausal women with osteoporosis or with low bone mass
Reginster, Jean-Yves ULiege; McClung, M.; Cox, D. et al

in Osteoporosis International (2010, May), 21(Suppl.1), 23-24

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See detailNew simplified analytical method for the Prediction of global stability of steel and composite sway frames
Demonceau, Jean-François ULiege; Ly, Dong Phuong Lam ULiege; Coméliau, Ludivine ULiege et al

in Proceedings of the annaual stability conference, 2010 (2010, May)

Eurocode 4 is the European design code for composite construction; in its so-called EN 1994-1-1 version, the design of “non-sway buildings” is mainly covered. As a result, EC4 focuses on the check of ... [more ▼]

Eurocode 4 is the European design code for composite construction; in its so-called EN 1994-1-1 version, the design of “non-sway buildings” is mainly covered. As a result, EC4 focuses on the check of structural elements like beams, columns, slabs and joints. However, in the last years, the construction of taller buildings and larger industrial halls without wind bracing systems tends to make global instability a relevant failure mode, which is not well covered by Eurocode 4. Recently, intensive experimental, numerical and theoretical investigations have been carried out at Liège University. The latter aimed at improving the knowledge in the field of sway composite building frames and at developing appropriate design rules. The rotational behavior of the beam-to-column composite joints is one of the key aspects of the problem to which a special attention has been paid. This paper reflects investigations carried out at Liege University on this topic. In particular, an innovative simplified analytical method to predict the ultimate loading factor and the associated collapse mode of both steel and composite frames subjected to static loadings is presented. [less ▲]

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See detailThe efficacy of a communication skills training program : is it possible to predict assessment and supportive skills learning among residents?
Bragard, Isabelle ULiege; Merckaert, I.; Libert, Y. et al

in Psycho-oncology (2010, May), 19(Suppl.2)(1-313), 248

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See detailThe earthquake sedimentary record of the Marmara Sea, Turkey
Drab, Laureen; Hubert, Aurelia ULiege; Schmidt, Sabine et al

in Geophysical Research Abstracts (2010, May)

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See detailAnalyse de la formation des entraîneurs. Impact d’un cycle de cours destinés à des entraîneurs débutants (niveau 1)
Theunissen, Catherine ULiege; Langer, Patrick; Cloes, Marc ULiege

in Amans-Passaga, Christine; Gal-Petitfaux, Nathalie; Terral, Philippe (Eds.) et al L’intervention en sport et ses contextes institutionnels : cultures et singularité de l’action (2010, May)

This study aims to identify the expectations of the people participating to education units proposed to volunteer beginning coaches in volleyball, to follow the development of one unit and to determine ... [more ▼]

This study aims to identify the expectations of the people participating to education units proposed to volunteer beginning coaches in volleyball, to follow the development of one unit and to determine its impact within the coaching activity of one subject. Some differences have been underlined between the opinions of the participants and those of the staff members. There was a large coherence between the latters about the conceptions of the coaches preparation. The subject who was observed after the completion of the unit clearly used contents propsed during the programme. [less ▲]

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See detailRéappropriation et réapparition. Survivances de Vertigo
Mélon, Marc-Emmanuel ULiege

Conference (2010, May)

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See detailValidation of the french version of the Maslach Burnout Inventory among physicians
Bragard, Isabelle ULiege; Etienne, Anne-Marie ULiege; Hansez, Isabelle ULiege et al

in Psycho-oncology (2010, May), 19(Suppl.2)(1-313), 249

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See detailActive solar retrofit of a residential house, a case study in Egypt
Attia, Shady ULiege

in Proceedings of the National Solar Conference 2010 (2010, May)

There are extraordinary opportunities to reduce the consumption of fossil energy in retrofitting existing buildings in Egypt. For instance, South Tahrir (150km northwest of Cairo) falls in the arid ... [more ▼]

There are extraordinary opportunities to reduce the consumption of fossil energy in retrofitting existing buildings in Egypt. For instance, South Tahrir (150km northwest of Cairo) falls in the arid climate zone with an annual-average daily global irradiation value of 23.76 MJ/m2 and for diffuse irradiation they are 9.65 MJ/m2 for Cairo and approximately 3300 hours of full sunshine. However, in extreme climates like Egypt, conditions show relatively high demand for cooling and heating energy. To overcome this problem and to examine these opportunities, this study evaluated the active solar retrofit of a passive house built in South Tahrir city. The aim of the study was to investigate the potential of active solar retrofits. The building performance was evaluated using TRNSYS, and monitored during two years of occupancy (2004-2006) to evaluate the performance and energy/carbon emissions reduction. The research took into consideration active design strategies such as solar thermal domestic water heating, photovoltaic panels and solar thermal air conditioning. First, the performance of the passive house before and after the retrofit was represented and compared. The house thermal and electric loads were compared to the solar thermal and electric production. Then results were evaluated to assess the suitability of each strategy based on energy performance. The final result of this study proved theoretically the feasibility of installing solar hot water collectors and solar thermal air conditioning. For this specific location and climate conditions an active solar retrofit of the residential house is energetically rewarding. Future solutions should address all of the thermal loads (cooling, heating, DHW) with thermal energy collection and only the electric loads (internal loads and auxiliary components) with photovoltaic collection. However, as long as the prices of electricity are highly subsidized the active solar retrofit is still considered not be cost effective. [less ▲]

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See detailThe dynamic interplay between roots and soil moisture
Garré, Sarah ULiege; Vanderborght, Jan; Javaux, Mathieu et al

in Geophysical Research Abstracts (2010, May)

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See detailCorrection of Thin Shell Finite Element Magnetic Models via a Subproblem Method
Dular, Patrick ULiege; Dang, Quoc Vuong ULiege; V Sabariego, Ruth ULiege et al

in Proceedings of the 14th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC2010) (2010, May)

A sub-problem finite element method is developed for correcting the inaccuracies near edges and corners inherent to thin shell models, for both magnetostatic and magnetodynamic problems. A thin shell ... [more ▼]

A sub-problem finite element method is developed for correcting the inaccuracies near edges and corners inherent to thin shell models, for both magnetostatic and magnetodynamic problems. A thin shell solution, supported by a simplified mesh near the thin structures, serves as a source of a correction problem with the actual volumic thin regions alone in a homogeneous medium, concentrating the meshing effort on the thin regions only. Improvements of local fields are efficiently achieved and allow accurate force and loss calculations. [less ▲]

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See detailThoughts on fetal growth: tissues and nutrition
Battisti, Oreste ULiege

Conference (2010, May)

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See detailMicrowave-assisted conversion of carbohydrates. State of the art and outlook.
Richel, Aurore ULiege; Laurent, Pascal ULiege; Wathelet, Bernard ULiege et al

Conference (2010, May)

The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks (i.e. lignocellulosic biomass) is nowadays an area of outmost interest. In this context, the implementation of fast ... [more ▼]

The valorisation of carbohydrates arising from the hydrolysis of renewable feedstocks (i.e. lignocellulosic biomass) is nowadays an area of outmost interest. In this context, the implementation of fast, expeditous and cost-effective methodologies for the modification of these naturally occurring compounds is becoming a prerequisite. In this sense, the application of microwaves has gained progressive attention in laboratories for making a range of high-added value sugars derivatives scaffolds. Its advantages are numerous and include enhacement of reaction rates and yields combined to improved regio-, chemo- and anomeric selectivities. Since the first publications of Gedye et Giguere in 1986, the use of microwave has progressively emerged as a popular non conventional heating source in the field of organic synthesis.1 Nevertheless, its application in the area of carbohydrate chemistry is less documented.2, 3 Although research in this field is still in its infancy, recourse to microwaves often provides, with remarkable yields and atom efficiency, new carbohydrate-based structures that are not easily available by any another means (or only via painstaking multi-step protocols). This communication proposes therefore selected, recent and non exhaustive illustrations of the application of microwaves to promote famous carbohydrates “model” reactions. The scale-up of such microwave-assisted reactions is also presented. [less ▲]

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See detailInterpreting the current evidence on glucosamine sulfate effects as a symptom-modifying drug in knee osteoarthtritis
Reginster, Jean-Yves ULiege

in Osteoporosis International (2010, May), 21(Suppl.1), 395

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See detailRecent developments in optimization of flexible components of multibody systems
Duysinx, Pierre ULiege; Emonds-Alt, Jonathan; Virlez, Geoffrey ULiege et al

Conference (2010, May)

Recently mechanical engineering has extended from a component to a system oriented approach. The structural analysis of components is now completed by the whole mechanical system simulation using ... [more ▼]

Recently mechanical engineering has extended from a component to a system oriented approach. The structural analysis of components is now completed by the whole mechanical system simulation using multibody system analysis. This evolution aims at capturing better the real loading conditions accounting for the component interaction and couplings in the system. Structural optimization is continuing along the same tracks. Recent works in structural optimization have tried to optimize components with respect to loadings conditions defined through dynamic loading coming from multibody system dynamic analysis. Generally, optimization techniques consider that the structural component is isolated from the rest of the mechanism and use simplified quasi-static load cases to mimic the complex loadings in service. In contrast, we have shown in previous works devoted to topology optimization that an optimization directly based on the dynamic response of the flexible multibody system leads to a more integrated approach. In order to overcome the limitations of some previous approaches, a more integrated optimization technique is proposed here, based on the nonlinear finite element approach for flexible multibody systems. The non linear finite element formalism accounts for both large rigid-body motions and elastic deflection of the structural components. In previous work, the optimal design of components was realized as an optimal truss / beam layout. The present communication investigates the optimal design of components considered as a continuum medium. We study first sizing optimal design of structural components and we later extend the method to optimal material distribution approach to address their lay out optimization. The continuum domain is discretized into finite elements. For sizing optimization, the design variables are wall-thickness and lumped element variables. For topology optimization the design variables are classically density-like parameters associated to a power law interpolation of effective material properties for intermediate densities, also known as Simply Isotropic Material with Penalization (SIMP). This study assesses the feasibility of this approach, which extends optimization techniques to continuum flexible bodies included in MBS. The numerical implementation is conducted in SAMCEF MECANO for the flexible MBS analysis and BOSS Quattro for the optimization shell. The nonlinear equations of motion are solved using a generalized-a time integration scheme while the sensitivity analysis of mechanical responses is based on a direct differentiation method or finite differences. For sizing and parametric optimization the paper investigates and compares several optimization approaches methods such as classical gradient-based methods (SQP, Augmented lagrangian), sequential convex programming methods (CONLIN, MMA), but also surrogate-based optimization method (with Neural Networks) combined with genetic algorithms. The formulation of the problem is also discussed, and its influence on the convergence history is illustrated. Optimal sizing, shape and topology optimization of a simple model of a robot are addressed. The optimization approach is illustrated on numerical applications of sizing optimization of robot arms during trajectory tracking and lightweight layout optimal design of automotive components. [less ▲]

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See detailLong term agreement between two different centres regarding joint space narrowing measurement in knee osteoarthritis
Deroisy, Rita ULiege; Roux, J. P.; Bruyère, Olivier ULiege et al

in Osteoporosis International (2010, May), 21(Suppl.1), 233-234

Detailed reference viewed: 23 (5 ULiège)
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See detailBisphosphonates and glucocorticoid osteoporosis in men : results of a randomized controlled trial comparing zoledronic acid with risedronate
Sambrook, P. N.; Roux, C.; Devogelaer, J. P. et al

in Osteoporosis International (2010, May), 21(Suppl.1), 19

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See detailUsing prior knowledge to accelerate online least-squares policy iteration
Busoniu, Lucian; De Schutter, Bart; Babuska, Robert et al

in Proceedings of the 2010 IEEE International Conference on Automation, Quality and Testing, Robotics (2010, May)

Reinforcement learning (RL) is a promising paradigm for learning optimal control. Although RL is generally envisioned as working without any prior knowledge about the system, such knowledge is often ... [more ▼]

Reinforcement learning (RL) is a promising paradigm for learning optimal control. Although RL is generally envisioned as working without any prior knowledge about the system, such knowledge is often available and can be exploited to great advantage. In this paper, we consider prior knowledge about the monotonicity of the control policy with respect to the system states, and we introduce an approach that exploits this type of prior knowledge to accelerate a state-of-the-art RL algorithm called online least-squares policy iteration (LSPI). Monotonic policies are appropriate for important classes of systems appearing in control applications. LSPI is a data-efficient RL algorithm that we previously extended to online learning, but that did not provide until now a way to use prior knowledge about the policy. In an empirical evaluation, online LSPI with prior knowledge learns much faster and more reliably than the original online LSPI. [less ▲]

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See detailComment un cours en PBL aide l'étudiant à devenir apprenant
Sadzot, Agnès ULiege; Massart, Valérie ULiege; Duchesnes, Christiane ULiege et al

in Ammar, Adil; Sbihi, Mohammed (Eds.) AIPU 2010 Réformes et changements pédagogiques dans l'enseignement supérieur (2010, May)

En 2006-2007, le cours d'Apprentissage de la Démarche Logopédique (ADL) est créé dans la formation en logopédie à l'Université de Liège. Il s'agit d’une approche clinique adoptant une méthodologie de type ... [more ▼]

En 2006-2007, le cours d'Apprentissage de la Démarche Logopédique (ADL) est créé dans la formation en logopédie à l'Université de Liège. Il s'agit d’une approche clinique adoptant une méthodologie de type Problem-Based Learning. En février 2009, une recherche par groupes focalisés a été réalisée dans le but d'évaluer l'impact de ce nouveau cours sur la formation clinique des étudiants. Les principaux résultats issus de cette recherche concernent le vécu des apprenants, et la façon dont les ADL ont modifié leur "métier d'étudiant". En effet, l'analyse des groupes focalisés suggère que les ADL permettent aux apprenants de développer des aptitudes transversales, telles que confiance en soi, capacités de communication, travail en équipe, esprit critique, organisation du travail, questionnement clinique, essentielles à la pratique professionnelle en logopédie. Par ailleurs, les ADL renforcent les liens entre théorie et pratique, en exigeant la mobilisation et la mise en réseau de toutes les connaissances acquises. [less ▲]

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See detailModèle de simulation des performances d'une chaudière fioul à condensation de chauffage domestique
Makaire, Danielle ULiege; Ngendakumana, Philippe ULiege

in Energies et transports durables : SFT10, Le Touquet 25-28 mai 2010 (2010, May)

The developed model in this work is similar to a classical model of a conventional boiler (combination of a combustion chamber and a water-flue gas heat exchanger) to which a model of a heat exchanger for ... [more ▼]

The developed model in this work is similar to a classical model of a conventional boiler (combination of a combustion chamber and a water-flue gas heat exchanger) to which a model of a heat exchanger for condensation has been added. This latter has been simulated by a cooling coil divided into several elements The developed model has been applied on a condensing whose nominal useful power is 24.6 KW. After the determination of the nominal parameters, tests have been performed to validate the model in different working conditions of the boiler. The two main parameters whose influence has been investigated are : the return water temperature and the overall excess air. [less ▲]

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See detailSIMULATION MODEL OF A GAS-FIRED CONDENSING BOILER AT FULL LOAD OPERATION IN STEADY-STATE REGIME
Makaire, Danielle ULiege; Ngendakumana, Philippe ULiege

in ASME-ATI-UIT 2010 Conference on Thermal and Environmental Issues in Energy Systems (2010, May)

The model in this paper was developed to predict thermal performances of gas-fired condensing boilers. The structure of the developed model is similar to the one of a conventional boiler with a main ... [more ▼]

The model in this paper was developed to predict thermal performances of gas-fired condensing boilers. The structure of the developed model is similar to the one of a conventional boiler with a main counterflow gas-water heat exchanger, at which a condensing heat exchanger is added. Prior to the second heat exchanger, the exhaust gas are converted into equivalent wet air. The condensing heat exchanger is divided into smaller parts and each part is simulated by a cooling coil model currently used in HVAC simulation. Several tests have been performed in steady-state regime on a household gas-fired boiler whose nominal output is 24 kW. The experimental results are compared to the model results and the results are discussed. [less ▲]

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See detailResponse of the European ecosystems to climate change: a modelling approach for the 21st century
Dury, Marie ULiege; Warnant, Pierre; François, Louis ULiege et al

Poster (2010, May)

According to projections, over the 21st century, significant climatic changes appear and will be strengthened all over the world with the continuing increase of the atmospheric CO2 level. Climate will be ... [more ▼]

According to projections, over the 21st century, significant climatic changes appear and will be strengthened all over the world with the continuing increase of the atmospheric CO2 level. Climate will be generally warmer with notably changes in the seasonality and in the precipitation regime. These changes will have major impacts on the environment and on the biodiversity of natural ecosystems. Geographic distribution of ecosystems may be modified since species will be driven to migrate towards more suitable areas (e. g., shifting of the arctic trees lines). The CARAIB dynamic vegetation model (Carbon Assimilation in the Biosphere) forced with 21st century climate scenarios of the IPCC (ARPEGE-Climat model) is used to illustrate and analyse the potential impacts of climate change on tree species distribution and productivity over Europe. Changes in hydrological budget (e. g., runoff) and fire effects on forests will also be shown. Transient runs (1975-2100) with a new dynamic module introduced in CARAIB are performed to follow the future evolutions. In the new module, the processes of species establishment, competition and mortality due to stresses and disturbances have been improved. Among others, increased atmospheric CO2 and warmer climate increase tree productivity while drier conditions decrease it. Regions with more severe droughts will also be affected by an increase of wildfire frequency, which may have large impacts on vegetation density and distribution. [less ▲]

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See detailTime integration of finite rotations in flexible multibody dynamics using Lie group integrators
Bruls, Olivier ULiege; Cardona, Alberto

Conference (2010, May)

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See detailEvaluation du potentiel de récupération d’énergie à l’échappement d’un moteur TDI à l’aide d’un cycle de Rankine organique (ORC)
Declaye, Sébastien ULiege; Quoilin, Sylvain ULiege; Lemort, Vincent ULiege

Poster (2010, May)

Une étude expérimentale a été menée sur un cycle de Rankine organique de faible puissance (2,5kW). Les résultats expérimentaux ont permis de calibrer un modèle du cycle qui a ensuite été utilisé afin ... [more ▼]

Une étude expérimentale a été menée sur un cycle de Rankine organique de faible puissance (2,5kW). Les résultats expérimentaux ont permis de calibrer un modèle du cycle qui a ensuite été utilisé afin d’évaluer le potentiel de récupération d’énergie à l’échappement d’un moteur TDI pour 13 points de fonctionnement représentatifs. Les résultats montrent la possibilité de produire jusqu’à 2,4kW de puissance mécanique additionnelle. La fraction d’énergie récupérée (ERR) pouvant atteindre 6,8% de la puissance à l’arbre moteur. [less ▲]

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See detailUne approche théorique contingente du design des systèmes de contrôle de gestion : le cas des collectivités locales du Bénin
Togodo Azon, Degodo Aimé ULiege; Van Caillie, Didier ULiege; Pichault, François ULiege

in Association Francophone de Comptabiltélité (Ed.) Actes du 31ème Congrès de l'Association Francophone de Comptabilité (2010, May)

The current paper aims to elaborate a theoretical research model on the determinants of the management control systems in local collectivities in Sub-Sahara Africa. A critical state of the art allowed us ... [more ▼]

The current paper aims to elaborate a theoretical research model on the determinants of the management control systems in local collectivities in Sub-Sahara Africa. A critical state of the art allowed us to conclude that (1) organizational factors and (2) non organizational factors as the global institutional framework (the legal and regulatory pressures, the financial pressures and the political pressures) and the sociocultural framework (the domestic and group pressures, the ethnic pressures, the religious pressures and the pressures due to localization) are the major key determinants in the elaboration, the adoption and the efficiency of the Management Control System in local Sub-Saharian collectivities. [less ▲]

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See detailHydraulic behavior of Piano Key Weirs: experimental approach
Machiels, Olivier ULiege; Erpicum, Sébastien ULiege; Archambeau, Pierre ULiege et al

in Janssen, Robert; Chanson, Hubert (Eds.) 3rd Int. Junior Researcher and Engineer Worjshop on Hydraulic Structures (2010, May)

The Piano Key Weir (PKW) is a particular geometry of weir similar to a labyrinth shape that features overhanging cycle ends to reduce the base length. Together with its high discharge capacity for low ... [more ▼]

The Piano Key Weir (PKW) is a particular geometry of weir similar to a labyrinth shape that features overhanging cycle ends to reduce the base length. Together with its high discharge capacity for low heads, this geometric feature makes the PKW an interesting solution for dam rehabilitation, permitting the placement of the weir directly on dam crest. However, PKW stays a new type of weir, firstly designed in 2001 and built for the first time in 2006 by Electricité de France (EDF). Even if the first experimental studies confirmed its discharge capacities, lacks persist in the understanding of the flow behaviour upstream, along and downstream of this complex structure. This paper presents the mean results and observations obtained from experiments on a large scale model of PKW. The hydraulics of the structure is clarified based on measurements of water depths, pressures, velocities and discharges on each part of the weir. These observations explain the effect of geometric improvements proposed in former studies. [less ▲]

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See detailFalse memories and hemispheric processing in aging
Gajewski, Celine; Dehon, Hedwige ULiege; Peigneux, Philippe ULiege et al

Poster (2010, May)

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See detailSmooth multiple-region mesh generation for biomedical applications
D'Otreppe, Vinciane ULiege; Boman, Romain ULiege; Ponthot, Jean-Philippe ULiege

in ECCM 2010, 4th European Conference on Computational Mechanics (2010, May)

The finite element method is commonly used in biomedical applications for the simulation of the behaviour of biological structures. However, extracting finite element meshes from medical data is still ... [more ▼]

The finite element method is commonly used in biomedical applications for the simulation of the behaviour of biological structures. However, extracting finite element meshes from medical data is still very challenging. In this article, an innovative system that efficiently reconstructs smooth, multi-material, 3D surface meshes from medical images is presented. Our approach is based on an enhanced Marching Tetrahedra algorithm, which extracts boundary surfaces between different materials within one sweep of the image stack in an integrated manner. Moreover,Multi-Level Partition of Unity implicit models are used to obtain a smooth and accurate surface representation of the original binary sampled surface. Mesh smoothing and decimation algorithms were also revised to adapt to the multi-material nature of the system as well as to adhere to the underlying volume data. [less ▲]

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