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See detailRéforme de Bologne : quelles transformations de l’évaluation des apprentissages ?
Gorga, Adriana; Charlier, Bernadette; Gilles, Jean-Luc ULg

Conference (2006, May)

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See detailNew silicone based antifoam for fermentation
Etoc, Ariane; Delvigne, Frank ULg; Lecomte, Jean-Paul et al

Conference (2006, April 30)

Detailed reference viewed: 10 (0 ULg)
See detailContracting in manufacturing networks with inventories
Arda, Yasemin ULg; Hennet, Jean-Claude

Conference (2006, April 18)

An important issue in the management of supply chains and manufacturing systems is to achieve the desired customer service level while respecting the individual economic objectives of the partners. These ... [more ▼]

An important issue in the management of supply chains and manufacturing systems is to achieve the desired customer service level while respecting the individual economic objectives of the partners. These objectives are generally antagonistic and can lead to contradictory choices in the context of a network with a high degree of local decisional autonomy. The challenge involved is to determine a coordination mechanism that avoids global loss of economic efficiency and to solve nonlinear optimization problems that capture the key dynamics of a complex production/inventory system. This study investigates a two-stage serial supply chain with one manufacturer and one supplier. The manufacturer, producing goods to serve a Poisson demand process, procures a key component from his supplier. At each production facility, the successive processing times of the units are independent exponential random variables. In the decentralized setting considered, each firm manages the local production/inventory control system while attempting to maximize his own steady state expected profit. The main operational decision at each stage is the level of the inventory control parameter. In the game theory framework, the partners play a two-stage game of the Stackelberg type. The manufacturer leads the game by setting the component purchasing price as a function of the observed lateness of delivery. In the considered make-to-stock queuing system, the production facility of the supplier behaves as an M/M/1 queue. However, the departure of units from the finished-goods inventory of the supplier is not a Poisson process. In order to derive closed form results, the method of Lee and Zipkin (1992) is used to approximate the limiting probabilities of the second stage production process. The supplier’s profit function is concave and the optimal action of the supplier can be correctly anticipated by the manufacturer. The manufacturer’s constrained optimization problem consists of determining the optimal values of the contract parameters and the second stage base-stock level. It is shown that using the defined contracting scheme, the system optimal solution is obtained as the Stackelberg equilibrium. [less ▲]

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See detailWind tunnel protocol for spray drift assessment
stainier, Charles; Lebeau, Frédéric ULg; Destain, Marie-France ULg et al

Conference (2006, April 11)

The objective of wind tunnel protocol is to measure spray drift in a reproducible way in order to evaluate the relative drift potential

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See detailImpact of a Greenland deglaciation on climate during the next millennia
Driesschaert, Emmanuelle; Brovkin, Victor; Fichefet, Thierry et al

Conference (2006, April 04)

A new Earth system model of intermediate complexity, LOVECLIM, has been developed in order to study long-term future climate changes. It includes an interactive Greenland and Antarctic ice sheet model ... [more ▼]

A new Earth system model of intermediate complexity, LOVECLIM, has been developed in order to study long-term future climate changes. It includes an interactive Greenland and Antarctic ice sheet model (AGISM) as well as an oceanic carbon cycle model (LOCH). Those climatic components can have a great impact on future climate. The few studies in recent literature assessing the impact of polar ice sheets on future climate draw very different conclusions, which shows the need for developing such a model. A set of numerical experiments have been performed in order to study the possible perturbations of climate induced by human activities over the next millennia. A particular attention is given to the Greenland ice sheet. In most of the projections, the Greenland ice sheet undergoes a continuous reduction in volume, leading to an almost total disappearance in the most pessimistic scenarios. The impact of the Greenland deglaciation on climate has therefore been assessed through a sensitivity experiment using the scenario SRES A2. The removal of the Greenland ice sheet is responsible for a regional amplification of the global warming inducing a total melt of Arctic sea ice in summer. The freshwater flux from Greenland generates large salinity anomalies in the North Atlantic Ocean that reduce the rate of North Atlantic Deep Water formation, slowing down slightly the oceanic thermohaline circulation. [less ▲]

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See detailDu management DE la RSE au management PAR la RSE. Etude de cas d’une PME belge
Delhaye, Christine; El Abboubi, Manal ULg; Xhauflair, Virginie ULg

Conference (2006, April)

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See detailDynamique des structures tourbillonnaires participant à la production du bruit de fente
Glesser, Martin; Billon, Alexis ULg; Valeau, Vincent et al

Conference (2006, April)

Des sons auto-entretenus (sifflements de forte intensité) peuvent être produits par les bouches de soufflage des systèmes de ventilation. L'impact du jet produit par la bouche sur une grille de protection ... [more ▼]

Des sons auto-entretenus (sifflements de forte intensité) peuvent être produits par les bouches de soufflage des systèmes de ventilation. L'impact du jet produit par la bouche sur une grille de protection située en aval induit une perturbation pouvant remonter l'écoulement et venir exciter le jet à sa naissance, établissant ainsi une boucle d'auto-entretien. Pour certains nombres de Reynolds et distances "sortie du jet / obstacle", un couplage entre les sons auto-entretenus et le conduit de soufflage est observé. La résonance du conduit contrôle alors la fréquence et amplifie le niveau sonore. Cette étude s'intéresse à la production sonore résultant de ce couplage. Les structures tourbillonnaires crées dans les couches de cisaillement du jet jouent un rôle prépondérant : la synchronisation entre leur création ou leur impact sur l'obstacle et le champ acoustique rayonné par le conduit résonnant influe fortement sur la production sonore. Or les résultats disponibles dans la littérature pour des configurations géométriques ressemblantes ne permettent pas de clarifier cette synchronisation. Un dispositif expérimental où un jet plan rectangulaire heurte une plaque fendue (configuration géométrique appelée bruit de fente) est donc étudié à l'aide de mesures vélocimétriques. La comparaison de la fluctuation du signal de vitesse dans le cône potentiel du jet (directement lié à la vitesse acoustique) et du signal de vitesse dans la couche de cisaillement (contenant des informations sur le passage des structures tourbillonnaires) permet de clarifier la dynamique de ces structures. L'information obtenue permet alors d'évaluer la synchronisation entre le champ acoustique et le champ tourbillonnaire. Cette étude contribuera à terme a l'implémentation d'un modµele du bruit de fente basé sur la théorie aéroacoustique de Howe. [less ▲]

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See detailWho Poisoned 'la Marquise'? Tradition versus History
Peere, Isabelle ULg

Conference (2006, April)

This study analyses the „story“ of the ballad of 'La Marquise empoisonnée' over time and space - from its earliest record (1841) to its presence in the repertoires of contemporary youth songsters and ... [more ▼]

This study analyses the „story“ of the ballad of 'La Marquise empoisonnée' over time and space - from its earliest record (1841) to its presence in the repertoires of contemporary youth songsters and revival singers, and from its native France to French-America. While textual stability/variation helps define the song’s emotional core, the told/untold parts of the tale reveal the space open to individual performative as well as interpretive (re)creation. In the light of this textual data – the only (poetic) context available for the song – manifesting stock characterization, impersonal narrative perspective, vivid dramatization, sparse idiom, etc. – the contention is that the song’s persistence across both sides of the Atlantic owes as much to the traditional process that shaped it as Volkslied as to its possible historical background or literary/semi-literary origin. [less ▲]

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See detailThe comutation of Linking Errors
Monseur, Christian ULg; Berezner, A.

Conference (2006, April)

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See detailData assimilation as a tool for upscaling
Vandenbulcke, Luc ULg; Barth, Alexander ULg; Ben Bouallegue, Z. et al

Conference (2006, April)

In ocean and atmospheric sciences, grid nesting is a common procedure in order to achieve (very) high resolution model outputs in regions of particular interest, at an acceptable computational cost ... [more ▼]

In ocean and atmospheric sciences, grid nesting is a common procedure in order to achieve (very) high resolution model outputs in regions of particular interest, at an acceptable computational cost. Nesting of grids can be passive (one-way nesting) or active (two-way nesting, with feedback from the high resolution to the low resolution grid). The benefits of active nesting have been shown multiple times in the litterature (see e.g. [1]). The positive effect of the feedback is visible inside the nested grid, but also outside of it, as corrections are advected with the flow. It must be noted however that in many operationnal implementations, only passive nesting is used, usually because active nesting requires too much data exchange between models, which should then wait for each other during their run. Data assimilation techniques are also widespread in oceanic and atmospheric models. They are usually applied in order to merge observations in models, but also e.g. to merge different outputs from ensemble runs of a model, to merge outputs from different models, or to replace downscaling between nested grids (see [3]). In our work, we present an alternative to active nesting (for implementations currently using passive nesting). First, the low-resolution model is run, followed by the local model. Afterwards, the low-resolution model is run once more, assimilating outputs from the local model as pseudo-data. The benefits of this approach over simple passive nesting are shown using a twin experiment. The GHER model (see [2]) is configured with a 0.25 resolution of the Mediterranean Sea, and with a 0.05 resoluion of the North-Western part; a twin experiment is then set. The reference run uses full two-way nesting, another run uses one-way nesting, and in a third run the assimilation procedure described above is implemented.Conclusions from this experiment are that our "upscaling" has positive impacts on the forecasts, provided a fair amount of EOFs is used during (reduced-rank) assimilation cycles. Finally, the set-up of ongoing work to implement our upscaling procedure in a realistic, operationnal system (the MFS system) is presented. [less ▲]

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See detailCriteria for biogenicity of morphological signatures
Javaux, Emmanuelle ULg

Conference (2006, April)

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See detailValidation expérimentale d’un modèle de diffusion pour l’acoustique des locaux couplés
Billon, Alexis ULg; Picaut, Judicaël; Valeau, Vincent et al

Conference (2006, April)

La modélisation du champ sonore au sein de locaux couplés acoustiquement au moyen d’ouvertures a déjà fait l’objet de nombreuses études. Néanmoins, des modèles à la fois rapides et précis restent encore à ... [more ▼]

La modélisation du champ sonore au sein de locaux couplés acoustiquement au moyen d’ouvertures a déjà fait l’objet de nombreuses études. Néanmoins, des modèles à la fois rapides et précis restent encore à développer, parti-culièrement dans le cas où trois ou quatre salles sont associées. Récemment, un modèle basé sur une équation de diffusion a été appliqué avec succès pour la prévision du champ sonore réverbéré au sein d’un ensemble de deux locaux couplés. Dans cette étude, l’équation de diffusion est résolue numériquement en trois dimensions à l’aide d’une méthode par éléments finis. Cette résolution permet ainsi d’obtenir le niveau et la décroissance sonore en tout point du domaine considéré, au prix d’un faible temps de calcul (quelques minutes). Dans cette étude, les résultats obtenus sont validés, à la fois en termes de niveau du champ sonore et temps de réverbération, à l’aide d’une campagne expérimentale menée dans deux salles de cours couplées entre elles. De plus, une comparaison est réalisée avec des résultats issus de la théorie statistique classique et d’un logi-ciel commercial de tir de rayons largement répandu. Les résultats obtenus montrent un bon accord entre le modèle de diffusion et les expériences. En revanche, la théorie stati-stique ne permet pas de rendre compte précisément de la distribution spatiale et de la décroissance de l’énergie sonore. Enfin, le gain de temps par rapport au logiciel de tir de rayons est très important. [less ▲]

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See detailDifférentes estimations du libre parcours moyen en acoustique des salles : influence sur l’estimation de l’énergie acoustique par un modèle de diffusion
Foy, Cédric; Billon, Alexis ULg; Valeau, Vincent et al

Conference (2006, April)

La plupart des outils de prévision en acoustique des salles sont basés sur le principe du tir de rayons. La précision des résultats dépend alors du nombre de rayons choisi, nécessairement important quand ... [more ▼]

La plupart des outils de prévision en acoustique des salles sont basés sur le principe du tir de rayons. La précision des résultats dépend alors du nombre de rayons choisi, nécessairement important quand la géométrie simulée est grande et/ou disproportionnée, ce qui implique alors des temps de calcul élevés. Pour ce type de géométrie, une méthode alternative, basée sur la résolution numérique d’une équation de diffusion, permet en revanche de réaliser des prévisions acoustiques au prix d’un coût numérique modeste. Ce modèle repose en particulier sur un coefficient de diffusion caractérisant la pièce. Ce coefficient est théoriquement proportionnel au libre parcours moyen (LPM) du local considéré, vérifiant classiquement l’expression 4V/S (V étant le volume de la salle, S la surface des parois). Il est souvent admis que cette valeur est valide pour une salle de dimensions homogènes et dans le cas d’un champ réverbéré diffus. Néanmoins, dans la présente étude nous montrons que pour des locaux particulièrement allongés ou plats, l’atténuation sonore, directement dépendante du coefficient de diffusion, est surestimée par ce modèle. Il en est de même pour des locaux dont la loi de réflexion aux parois s’écarte d’une loi de Lambert. Ainsi, afin d’améliorer les performances du modèle de diffusion, la solution envisagée consiste d’une part, à réaliser un calcul numérique préliminaire du LPM et d’autre part, à considérer les approches analytiques alternatives du LPM rencontrées dans la littérature. La méthode numérique retenue est basée sur le suivi de particules sonores, et permet d’établir le LPM à partir de l’ensemble des distances de collision entre deux parois, pour des conditions de réflexion quelconques. Les résultats de ces approches analytiques et numériques sont présentés en terme d’atténuation sonore pour un local plat et un local allongé, et sont comparés à ceux issus d’autres méthodes numériques. [less ▲]

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See detailAn efficient simulation tool for predicting chatter during cutting operations
Le Lan, Jean-Vincent; Masset, Luc ULg; Marty, Audrey et al

Conference (2006, April)

The trends in chatter prediction are to compute stability lobes showing the maximal depth of cut versus spindle speed, following the work of Tlusty, Tobias and, more recently, Altintas. For mass ... [more ▼]

The trends in chatter prediction are to compute stability lobes showing the maximal depth of cut versus spindle speed, following the work of Tlusty, Tobias and, more recently, Altintas. For mass production such as the production of automotive parts, this kind of approach is not suitable because the goal is to find cutting conditions stable and independent of perturbations inherent to machining (clamping, rough part dimensions...). Still, in this method, the greatest allowable depth of cut to avoid chatter at any spindle speed is considered. The model is based on Tlusty's theory and the local stiffness of the machined surface is computed through a static finite element analysis. The result is a chatter map of the machined surface showing the maximal depth of cut at each node. [less ▲]

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See detailNouvelles frontières de l’entreprise et gestion de l’emploi, le cas des centres d’appels
Rorive, Brigitte; Naedenoen, Frédéric ULg

Conference (2006, April)

To understand the link between new corporate boundaries and employment management, we must take the heterogeneity of the call centers industry and its companies into account. Often described for the ... [more ▼]

To understand the link between new corporate boundaries and employment management, we must take the heterogeneity of the call centers industry and its companies into account. Often described for the degradation of the employment and work conditions that it creates, the call center industry is nevertheless far to response to an unique logic of job management. Through four case studies, diversified according to 2 axes: the level of added value offered by the call centers and its organizational complexity, let emerge different kind of logics, influenced by the position of the studied company on these two axes. They show the existence of a link between the configuration of inter-organizational relationship and the internal politics of human resources and employment management. This link has an effect on the extreme difficulty to conciliate the worker’s and the organizations’s interests, particularly when the client heavily intervene in the call center internal management , or influence strongly its operations by contractual requirements. [less ▲]

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See detailBilan des projets d'encadrement des producteurs.
Sindic, Marianne ULg

Conference (2006, March 31)

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See detailThe Social outcomes of learning: civic and social engagement indicators
Baye, Ariane ULg; Mainguet, Christine

Conference (2006, March 24)

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See detailDes représentations d’enseignants et le modèle d’école prôné par le Décret-missions de la Communauté française de Belgique.
Van der Linden, Sylvie ULg; Beckers, Jacqueline ULg

Conference (2006, March 22)

Cette recherche a récolté et analysé les réactions de 48 enseignants (de 2e et de 6e années primaires du territoire de la Communauté Française de Belgique) à des situations de classes qui ont été créées ... [more ▼]

Cette recherche a récolté et analysé les réactions de 48 enseignants (de 2e et de 6e années primaires du territoire de la Communauté Française de Belgique) à des situations de classes qui ont été créées avec l’aide de praticiens ainsi que sur la base du Décret-missions, en ayant en point de mire la visée égalitaire. Les réactions recueillies expriment les missions que se donne personnellement, dans l’exercice de son métier, chaque enseignant interviewé. [less ▲]

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See detailCryo-optical test of the PLANCK reflectors
Roose, Stéphane ULg; Cucchiaro, Antonio ULg

Conference (2006, March 20)

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See detailWhat Justice for Rwanda? Gacaca versus Truth Commission?
Reuchamps, Min ULg

Conference (2006, March 18)

In post-genocide Rwanda, in addition to gacaca courts, a truth commission is needed in order to promote justice and foster reconciliation. In the context of transitional justice, retributive justice ... [more ▼]

In post-genocide Rwanda, in addition to gacaca courts, a truth commission is needed in order to promote justice and foster reconciliation. In the context of transitional justice, retributive justice, which seeks justice and focuses on the perpetrators, appears to be inadequate to lead a society towards reconciliation. Therefore, some forms of restorative justice, which emphasize the healing of the whole society, seem necessary. In Rwanda, gacaca courts and a truth commission are complementary. The former can bring justice, the latter can seek the truth; both crucial ingredients of a peaceful future for Rwandans. The essay opens with the discussion of the nature of the genocide and the responses to post-genocide Rwanda’s crisis. The second and third parts present the existent gacaca system and a theoretical framework for a truth commission. The combination of both approaches in view of the double goal of justice and reconciliation conclude this paper. [less ▲]

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See detailNext-generation phase-mask coronagraphy for extrasolar planetary system imaging
Mawet, D.; Riaud, Pierre ULg; Surdej, Jean ULg

Conference (2006, March 16)

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See detailTable ronde : Pour une analyse comparée de l'édition imprimée et informatique d’un même texte
Tilkin, Françoise ULg; Magnan, André

Conference (2006, March 16)

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See detailTechniques tomographiques : des outils de choix pour l’étude des réacteurs polyphasiques
Toye, Dominique ULg; Fransolet, Emmanuelle; Léonard, Angélique ULg et al

Conference (2006, March 14)

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See detailEffect of anti-androgenic substances on the sexual reproduction of the rotifer Brachionus calyciflorus.
Joaquim-Justo, Célia ULg; Snell, T.W

Conference (2006, March 11)

Many substances released in the aquatic environment have been reported to have disruptive effects on endocrine systems of vertebrates and invertebrates. In rotifers, some of these chemicals have been ... [more ▼]

Many substances released in the aquatic environment have been reported to have disruptive effects on endocrine systems of vertebrates and invertebrates. In rotifers, some of these chemicals have been shown to depress sexual reproduction at concentrations one to two orders of magnitude below those that affect asexual reproduction. The anti-androgen flutamide impacts sexual reproduction of rotifers at particularly low concentrations. We studied the effect of different types of putative endocrine disruptors on sexual reproduction of Brachionus calyciflorus. Contaminants tested were cyproterone acetate, an anti-androgen with a steroid-like structure, the pesticides fenitrothion and linuron which both have high affinity to the androgen receptor in vertebrates, although they are nonsteroidal molecules, and lindane a widely used pesticide that binds weakly to the androgen receptor in vertebrates. A series of endpoints relative to different steps of sexual reproduction were monitored to define critical functions affected and to get information on mechanisms of action. Fenitrothion, had the strongest impact on the sexual reproduction of rotifers. We observed a decrease in the proportion of mictic females among the ovigerous individuals and in the production of fertilized eggs per female that was proportional to the dose. The most sensitive parameter was the number of males produced per mictic female which was considerably higher in treated animals even at concentrations 10 times lower than the NOEC of asexual reproduction. [less ▲]

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See detailThe GBS: pro screening
MELIN, Pierrette ULg

Conference (2006, March 11)

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See detailEffect of annealing atmosphere on the galvanizing behaviour of a dual-phase steel
Khondker, Rubayat; Mertens, Anne ULg; McDermid, Joe R.

Conference (2006, March)

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See detailFirst-Principles Study of High-Pressure Phase Transitions in Si3N4
Xu, Bin ULg; Dong, Jianjun

Conference (2006, March)

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See detailExtensive epidural and paraspinal follicular Non-Hodgkin lymphoma
Scholtes, Félix ULg; Scholsem, M.; Matus, G. et al

Conference (2006, March)

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See detailDevelopment of the surface structure of TRIP steels prior to hot-dip galvanizing
Bellhouse, Erika M.; Mertens, Anne ULg; McDermid, Joe R.

Conference (2006, March)

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See detailAlteration in expression of connexin subtypes may play a role in human mesial temporal lobe epilepsy
Collignon, F.; Martin, Didier ULg; Wetjen, N.

Conference (2006, March)

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See detailLong-term outcome of Epilepsy surgery among 399 patients with non-lesional pathology including mesial temporal lobe sclerosis.
Scholsem, M.; Cohen-Gadol, A.; Martin, Didier ULg et al

Conference (2006, March)

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See detailNonlésional central lobule seizures : use of awake cortical mapping and subdural grid monitoring for resection of seizure focus
Collignon, F.; Cohen-Gadol, A.; Meyer, F. et al

Conference (2006, March)

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See detailDiscrete-time synchronization on the N-torus
Sarlette, Alain ULg; Sepulchre, Rodolphe ULg

Conference (2006, March)

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See detailLes femmes entrepreneures et la transmission d’entreprise
Constantinidis, Christina ULg; Cornet, Annie ULg

Conference (2006, March)

Detailed reference viewed: 17 (6 ULg)
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See detailImpact d'une exposition aiguë au cadmium sur les neuromastes du système latéral troncal et conséquences sur le comportement de fuite "C-Start" du bar (Dicentrarchus labrax L., Téléostéen, Moronidae)
Faucher, Karine ULg; Fichet, Denis; Miramand, Pierre et al

Conference (2006, March)

Les réponses comportementales du bar, Dicentrarchus labrax, ont été examinées après exposition aux ions cadmium en conditions contrôlées de laboratoire. Le but de cette étude était de découvrir si les ... [more ▼]

Les réponses comportementales du bar, Dicentrarchus labrax, ont été examinées après exposition aux ions cadmium en conditions contrôlées de laboratoire. Le but de cette étude était de découvrir si les ions cadmium étaient capables d’inactiver les neuromastes du système latéral du poisson et de déterminer les conséquences comportementales d’un tel blocage sensoriel chez des poissons soumis à des dangers artificiels. Pour cela, le comportement de fuite des poissons en réponse à un jet d’eau artificiel a été enregistré grâce à une caméra vidéo analogique (25 images.s-1) avant et après l’exposition au cadmium. Le protocole expérimental a été testé sur des poissons dont le système latéral avait été artificiellement endommagé par des antibiotiques (gentamicine et streptomycine). Les contrôles histologiques réalisés en microscopie électronique à balayage ont montré que le traitement antibiotique avait détruit les neuromastes du système latéral. En parallèle, ces poissons ne répondaient plus aux stimulations engendrées par le jet d’eau après un tel traitement. Le comportement de fuite des poissons a ensuite été enregistré avant puis après une exposition au cadmium à deux concentrations différentes. Lorsque les bars ont été exposés à la première concentration testée (0.5 µg.l-1, ce qui représente la concentration maximale rencontrée dans des estuaires contaminés), aucune altération des tissus des neuromastes n’a été observée. De plus, avant l’exposition au cadmium, les poissons répondaient de manière positive à 98.41 ± 4.95 % (n = 42) des stimulations de leur système latéral (réponse de fuite face au jet d’eau). Après l’exposition au cadmium, aucune modification comportementale n’a été détectée : les poissons répondaient positivement à 95.16 ± 9.79 % (n = 41) des stimulations ( ² = 2.464, p = 0.116). Au contraire, la concentration la plus élevée de cadmium testée (5 µg.l-1, ce qui représente 10 fois la concentration rencontrée dans les estuaires fortement pollués) a entraîné de sévères dommages au niveau des tissus des neuromastes. Juste après une telle exposition au cadmium, les poissons présentaient seulement 41.67 ± 35.36 % (n = 2) de réponses positives aux stimulations de leur système latéral, alors qu’ils répondaient positivement à 95.93 ± 9.10 % (n = 41) des stimulations en conditions témoins ( ² = 24.562, p < 0.0001). Les neuromastes de leur système latéral ont semblé se régénérer au bout d’environ un mois après l’exposition au cadmium. Associée à cette régénération, à partir du 21ème jour suivant l’exposition au cadmium, leur comportement de fuite s’est restauré et n’était plus significativement différent de celui enregistré en conditions témoins (86.74 ± 20.82 %, n = 11, ² = 2.876, p = 0.090). Cette étude montre que si la concentration de cadmium de 5 µg.l-1 est capable d’endommager les neuromastes du système latéral et de provoquer des altérations comportementales chez les poissons, les bars exposés à 0.5 µg.l-1 de cadmium ne présentent ni dommage tissualaire de leurs neuromastes, ni modification comportementale. [less ▲]

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See detailLes enfants-loups
Strivay, Lucienne ULg

Conference (2006, February 25)

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See detailSpinal cord trauma
Martin, Didier ULg

Conference (2006, February 24)

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See detailInterprétation de la Sérologie Infectieuse.
HUYNEN, Pascale ULg

Conference (2006, February 23)

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See detailAssurance-vie disqualifiées ou requalifiées
Leleu, Yves-Henri ULg

Conference (2006, February 22)

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See detailGrowth Factors for Biotechnology
Grandfils, Christian ULg

Conference (2006, February 21)

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Peer Reviewed
See detailTips and tricks about aneurysm clipping
Martin, Didier ULg

Conference (2006, February 10)

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See detailGlacial-interglacial rain ratio variations: effect on atmospheric CO2 levels and sedimentary carbonate preservation/dissolution processes
Munhoven, Guy ULg

Conference (2006, February 10)

A reduction of the carbonate-carbon to organic-carbon export rain ratio during glacial times is commonly advanced to explain an important part of the observed glacial-interglacial atmospheric CO2 ... [more ▼]

A reduction of the carbonate-carbon to organic-carbon export rain ratio during glacial times is commonly advanced to explain an important part of the observed glacial-interglacial atmospheric CO2 variation. This hypothesis was tested and side-effects on the evolution of carbonate preservation/dissolution in the surface sediment explored with a multi-box model (MBM) of the ocean carbon cycle, fully coupled to a new transient advection-diffusion-reaction model (called MEDUSA) representing early diagenesis processes of carbonate minerals in the surface sediment. MEDUSA explicitly considers the role of organic matter remineralisation in the sediment column to enhance calcite (and aragonite) dissolution. It is fully bi-directional and takes chemical erosion into account in times when carbonate dissolution makes the sediment mixed-layer collapse faster than the sediment supply to the surface is able to counterbalance. Coupled model experiments were run for 240,000 years, forced by variable sea-level, temperature and salinity histories, and variable continental weathering inputs. Various scenarios for the evolution of the rain ratio over glacial to interglacial periods were adopted. A peak reduction of the rain ratio by 40% at the Last Glacial Maximum (LGM) was found to produce a net atmospheric pCO2 reduction of about 30ppm, on top of a 60ppm reduction produced by changing continental shelf carbonate accumulation and changing continental weathering inputs. The overall 90ppm oscillation compares well with the observed data. However, the effect on the model sedimentary record is clearly at odds with actual sediment records. The changes related to continental shelf processes and variable weathering flux depress the calcite saturation horizon by about 1km at the LGM; if rain ratio variations are also considered, that depression increases by another km. An assessment of the respective contributions from various model parameters will be presented. [less ▲]

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See detailOptimisation d'un contrat de coordination entre producteur et fournissuer
Arda, Yasemin ULg; Hennet, Jean-Claude

Conference (2006, February 06)

Cet article analyse comme un jeu de Stackelberg la négociation d’un contrat au sein d’une chaîne logistique à deux niveaux, qui est constituée de deux étages de production/stockage gérés par deux acteurs ... [more ▼]

Cet article analyse comme un jeu de Stackelberg la négociation d’un contrat au sein d’une chaîne logistique à deux niveaux, qui est constituée de deux étages de production/stockage gérés par deux acteurs différents : un producteur ayant une demande aléatoire d’un produit fini et son fournisseur de produit intermédiaire. [less ▲]

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See detailDEVELOPPEMENT D'INHIBITEURS SELECTIFS DE LA TRYPTOPHANE HYDROXYLASE
Giacomelli, Fabrice ULg; Luxen, André ULg; Lemaire, Christian ULg et al

Conference (2006, February 03)

Comprendre la façon dont le cerveau travaille et en particulier le mode de communication de ses cellules est un rêve que beaucoup de chercheurs caressent. A l’heure actuelle, une des rares certitudes à ... [more ▼]

Comprendre la façon dont le cerveau travaille et en particulier le mode de communication de ses cellules est un rêve que beaucoup de chercheurs caressent. A l’heure actuelle, une des rares certitudes à son sujet est qu’un de ses modes de transmission d’informations utilise des « messagers » chimiques appelés neurotransmetteurs. Parmi ceux-ci, la sérotonine (5-HT) revêt une importance particulière. En effet, la 5-HT est impliquée dans de nombreuses fonctions (apprentissage, locomotion, sommeil,…) et pathologies (dépressions, démences, schizophrénies,…). Dès lors, l'étude in vivo chez l'homme des neurones sérotoninergiques ainsi que la quantification de la vitesse de biosynthèse de la 5-HT sont des domaines d'études fondamentaux pour lesquels la tomographie à émission de positons (TEP) constitue un outil de choix. Pour mener à bien ces différentes expérimentations, deux stratégies sont envisageables : - L’emploi d'un traceur capable de suivre la chaîne métabolique du tryptophane conduisant à la 5-HT tout en évitant les autres voies métaboliques. - L’utilisation d'un inhibiteur de la TrpOH (enzyme limitant du processus). Dans le cadre de cette présentation, nous nous intéresserons plus particulièrement à la deuxième stratégie. [less ▲]

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See detailAbord des risques psychosociaux en Belgique.
Hansez, Isabelle ULg

Conference (2006, February 01)

Detailed reference viewed: 19 (4 ULg)
See detailPerinatal Group B Streptococcal Disease : Prevention strategies
Melin, Pierrette ULg

Conference (2006, February)

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See detailCaractérisation de matériaux poreux par analyse d'images 3D
Blacher, Silvia ULg; Gommes, Cédric ULg; Léonard, Angélique ULg et al

Conference (2006, February)

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See detailBiographie, trajectoire et réseaux en histoire littéraire
Dozo, Björn-Olav ULg; Provenzano, François ULg

Conference (2006, January 26)

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See detailIntérêt du dépistage de l'IRC
Krzesinski, Jean-Marie ULg

Conference (2006, January 26)

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See detailIntérêt du dépistage de l'IRC
Krzesinski, Jean-Marie ULg

Conference (2006, January 26)

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See detailEvaluating the performance of the Eastern Canadian Diatom Index (IDEC) at integrating water chemistry variability
Lavoie, Isabelle; Campeau, Stéphane; Darchambeau, François ULg et al

Conference (2006, January 06)

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See detailLangage et pratique de l'APP
VIERSET, Viviane ULg

Conference (2006, January 05)

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See detailIntermediate integer programming representations using value disjunctions
Louveaux, Quentin ULg

Conference (2006, January)

We introduce a general technique for creating an extended formulation of a mixed-integer program. We classify the integer variables into blocks, each of which generates a finite set of vector values. The ... [more ▼]

We introduce a general technique for creating an extended formulation of a mixed-integer program. We classify the integer variables into blocks, each of which generates a finite set of vector values. The extended formulation is constructed by creating a new binary variable for each generated value. Initial experiments show that the extended formulation can have a more compact complete description than the original formulation. We prove that, using this reformulation technique, the facet description decomposes into one “linking polyhedron” per block and the “aggregated polyhedron”. Each of these polyhedra can be analyzed separately. For the case of identical coefficients in a block, we provide a complete description of the linking polyhedron and a polynomial-time separation algorithm. Applied to the knapsack with a fixed number of distinct coefficients, this theorem provides a complete description in an extended space with a polynomial number of variables. On the basis of this theory, we propose a new branching scheme that analyzes the problem structure. It is designed to be applied in those subproblems of hard integer programs where LP-based techniques do not provide good branching decisions. Preliminary computational experiments show that it is successful for some benchmark problems of multi-knapsack type. [less ▲]

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See detailNew expandable biliary Polymer stent : results of an animal study
Weickert, U.; Steinkuhl, R.; Haverkamp, U. et al

Conference (2006)

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See detailPersistent Ischemic Mitral Regurgitation After Annuloplasty can be Predicted by Pre-operative Echocardiography.
Magne, Julien ULg; Pibarot, P; Dagenais, F et al

Conference (2006)

Detailed reference viewed: 14 (4 ULg)
See detailReal Time TEC monitoring using triple frequency GNSS data: a three step approach
Spits, Justine; Warnant, René ULg

Conference (2006)

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See detailProsodische aspecten van de tussentaal van vreemdetaalleerders
Rasier, Laurent ULg

Conference (2006)

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See detailEvaluation of geochemical determinism of trace elements in forest soils at regional scales. Lessons from the Permanent Forest Condition Survey.
Colinet, Gilles ULg; Baize, Denis; Lacroix, Daniel et al

Conference (2006)

The natural concentration of some elements in soil varies regionally according to lithology and locally with site-specific soil forming conditions such as relief or vegetation characteristics. Knowledge ... [more ▼]

The natural concentration of some elements in soil varies regionally according to lithology and locally with site-specific soil forming conditions such as relief or vegetation characteristics. Knowledge of the natural total concentrations of trace metals is now considered as prerequisite for the detection and assesment of anthropogenic contaminations. The Permanent Forest Inventory is a programme financed by the Ministry of the Walloon Region which aims at assessing and monitoring the forest condition in Southern Belgium. A part of this programme is dedicated to the implementation of a soil quality monitoring network. The observation plots are located at the intersection of a regular grid. Ten percent of the forest plots are planned to be sampled each year, which theorically supposes a time-frequency of 10 years for the monitoring considerations. Up to now, three field campaigns have been completed and 245 soil samples analyzed. Once a plot precisely located on the field, soil is sampled by mixing twenty 20cm-deep cores taken at the perimeter of a 10m large circle. Environmental observations complete the field work. These concern the physical environment, the soil morphology and the vegetation characteristics. The following parameters are measured in the laboratory: total organic carbon, total nitrogen, pHwater, pHKCl, exchangeable acidity and aluminium, cationic exchangeable capacity, NH4Cl-exctractible cations, total, mineral, and exchangeable P, and aqua-regia extractible concentrations of Ca, Mg, K, Al, Fe, Cr, Ni, Mn, Zn, Cu, Pb, Co, and Cd. Statistical analysis were then performed on the results in order to identify the driving factors of the soil properties, especially the geochemical determinism. Relationships between parameters and between parameters and field observations were thus investigated. Then the relevance of some classifications to differenciate the soil properties was evaluated and finally the spatial structure of the parameters was compared to the geographical distribution patterns of lithology, soil associations, or ecological territories. Although some diversity can be found among the soil series in this survey, soils developped from shales and/or sandstones are largely dominant. The first results therefore show a large extreme-based variability and moderate variation coefficients. The exchangeable cations and carbonate–sensitive parameters are the most variable. Frequency distributions are often largely skewed. Exchangeable cations appear to be more closely linked to acidity status than organic content while pseudo-total concentrations show rather good linear relationships between each other, to the exception of Pb and Cd. Both elements seem linked to specific lithologies, the presence of limestone for Pb, some clay-rich parent material or limestone for Cd. Among the soil characteristics, the nature and the abundance of the coarse fragments associated to the fine earth is the most differenciating criteria for pseudo-total content. Finally, there are clear convergences between spatial distributions of most of the elements and lithology or small natural regions. [less ▲]

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See detailStaging formality. Commerce and state in Katanga (DRC).
Rubbers, Benjamin ULg

Conference (2006)

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See detailRegular events in travel behaviour research: setup of a longitudinal websurvey
Cools, Mario ULg; Moons, Elke; Wets, Geert

Conference (2006)

One of the leading paradigms in modern travel behaviour research is the activity based approach, which considers travel as a derivative from the activities that individuals and households need or wish to ... [more ▼]

One of the leading paradigms in modern travel behaviour research is the activity based approach, which considers travel as a derivative from the activities that individuals and households need or wish to perform. Longitudinal designs provide the required framework for a better understanding of the dynamics of travel behaviour. Longitudinal data can be used to analyze behavioural adjustments some time before (response leads) or after (response lags) the occurrence of an event, or for instance to analyze routine behaviour. The questionnaire used to collect the data will be an activity diary. The respondents are asked to fill in all their activities performed that day. The diaries have to be filled in at least twice a week. These moments are randomly selected, but in weeks when a special event occurs, the days around this special event are questioned as well. Performing a longitudinal study has certain drawbacks however. The respondent burden can cause different side-effects, such as panel attrition, decreasing representativeness and, reporting errors. Thus, next to refreshing the sample regularly, trying to keep the respondents motivated is essential. A first step in lowering the respondent burden is to make the activity diaries user-friendly. An internetbased questionnaire makes interaction with respondents possible. The respondent’s current results can be graphically displayed (e.g. geographical map of activity-pattern), potentially awakening or strengthening the interest in the study. Logical rules (e.g. two activities on two different locations require a trip in between) can be formulated, and the interaction with the respondents allows the researcher to get feedback on “strange” answers, or on missing values, thus improving the data quality. This paper describes some potential paths to minimise sample attrition (e.g. internet-based interaction with respondents) and ways to refresh the sample. These findings are applied to the study of travel behaviour of Flemish households around school holidays. [less ▲]

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See detailRole of lipopeptides in the biological control activity of Bacillus subtilis
Ongena, Marc ULg; Jourdan, E.; Adam, A. et al

Conference (2006)

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See detailQuel avenir pour les produits fermiers ?
Duquesne, Brigitte ULg

Conference (2006)

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See detailMAXIMIZATION OF PULL-IN VOLTAGE OF MICRO-ELECTROMECHANICAL STRUCTURES USING TOPOLOGY OPTIMIZATION
Lemaire, Etienne ULg; Rochus, Véronique ULg; Fleury, Claude ULg et al

Conference (2006)

The design problem consists in maximizing the pull-in voltage using topology optimization method, which is formulated as an optimal material distribution. In addition to the classical volume constraint ... [more ▼]

The design problem consists in maximizing the pull-in voltage using topology optimization method, which is formulated as an optimal material distribution. In addition to the classical volume constraint, different structural constraints could be taken into consideration. Sensitivity analysis is one of the key issues of the optimization process and is performed with the formulation of eigenvalue topology optimization problems. Here the paper investigates topology optimization of strongly coupled electromechanical systems. To avoid important modifications of the electric field by the optimization process, this first study considers a non design electrode and use topology optimization to design an optimal suspension structure. Solution procedure of the optimization problem is based on CONLIN optimizer using a sequential convex programming. This method that has proved its efficiency in many structural problems (sizing, shape) is here tailored to strongly coupled multiphysics design problems under consideration. The choice of appropriate explicit convex approximations schemes for multiphysic problems is investigated. The proposed method is illustrated and validated on microbeam optimization applications. [less ▲]

Detailed reference viewed: 22 (2 ULg)
See detailDevelopment of customer-oriented space weather related services for real-time GPS applications
Bavier, Michaël; Warnant, René ULg; Lejeune, Sandrine et al

Conference (2006)

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See detailValidation of micro-CT: experimental protocol for titanium bone scaffolds
Kerckhofs, Greet ULg; Wevers, Martine; Lomov, Stepan Vladimirovitch et al

Conference (2006)

Detailed reference viewed: 6 (2 ULg)
See detailGALOCAD : GALileo LOcal Component for nowcasting and forecasting Atmospheric Disturbances
Warnant, René ULg; Kutiev, Ivan; Jodogne, Jean-Claude et al

Conference (2006)

Detailed reference viewed: 15 (0 ULg)