References of "Dissertations and theses"
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See detailLes paysans sans terre brésiliens en mouvement. Approche ethnographique.
Schoonbroodt, Bénédicte ULg

Master's dissertation (2003)

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See detailGENIEsim: the GENIE Science Simulator
Absil, Olivier ULg

Master of advanced studies dissertation (2003)

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See detailSérapis dans la glyptique et la bijouterie antiques
Veymiers, Richard ULg

Master's dissertation (2003)

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See detailLa "décomposition de l'UEO (1999-2003) : variables institutionnelles et militaires
Dumoulin, André ULg

Master's dissertation (2003)

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See detailPolyneuritis equi. Literatuurstudie & retrospectieve studie
Van Galen, Gaby ULg

Master's dissertation (2003)

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See detailCaractérisation des fluides bi-phasiques cryogéniques par absorption différentielle de rayonnements gamma
Carapelle, Alain ULg

Master of advanced studies dissertation (2003)

Detailed reference viewed: 59 (8 ULg)
See detailEtude structurale, acoustique et thermique d'une toiture double peau ventilée
Rossi, Barbara ULg

Master's dissertation (2003)

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See detailExistence d'une prescription d'ordre naturelle projectivement invariante
Radoux, Fabian ULg

Master's dissertation (2003)

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See detailAnalyse de politiques de gestion de stocks au sein d'une chaîne logistique
Arda, Yasemin ULg

Master's dissertation (2003)

Cette étude s'intéresse au problème de gestion de stock d’une entreprise dont le stock est approvisionné par des fournisseurs extérieurs. Les demandes arrivent en suivant un processus de Poisson simple et ... [more ▼]

Cette étude s'intéresse au problème de gestion de stock d’une entreprise dont le stock est approvisionné par des fournisseurs extérieurs. Les demandes arrivent en suivant un processus de Poisson simple et les délais d’approvisionnement sont des variables aléatoires à distribution de probabilité exponentielle. L’objectif est de minimiser le coût moyen de l’entreprise, qui comprend les coûts de stockage et de rupture de stock. Dans le cas d’un seul fournisseur disponible, le niveau de stock peut être modélisé comme une chaîne de Markov en temps continu et le critère à minimiser a la même forme que dans le modèle du Newsboy. Le problème qui tient compte de l’existence de plusieurs fournisseurs est plus complexe, puisque dans ce cas l’entreprise doit aussi choisir les fournisseurs pour passer les commandes en minimisant ses coûts. Si l’entreprise effectue les commandes chez le même fournisseur pendant la période analysée, elle doit choisir le fournisseur qui possède le taux de service maximal et par conséquent qui offre le coût minimal. Dans le cas du choix d’un fournisseur, éventuellement diffèrent, à chaque déclenchement de réapprovisionnement du stock, nous supposons que l’entreprise choisit les fournisseurs selon un processus de sélection de Bernoulli. Nous modélisons le système d’approvisionnement comme un réseau ouvert de files d’attente et en utilisant les fonctions de génération de probabilité, nous obtenons la distribution de probabilité du nombre total de commandes dans le réseau ouvert. Cette approche nous permet d’exprimer le critère à minimiser en fonction des variables de décision. Nous proposons aussi une heuristique pour résoudre ce problème. [less ▲]

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See detailApplication de l’échographie à l’ovum pick up chez la jument. Effet de la cystéamine sur la maturation des ovocytes équins mesuré par coloration au bis-benzamide et par transfert d’ovocytes.
Deleuze, Stefan ULg

Master's dissertation (2003)

Afin d’analyser l’effet de la cystéamine sur la maturation et la fécondation des ovocytes équins nous avons collecté des ovocytes par ponction folliculaire transvaginale échoguidée. Les ovocytes ont été ... [more ▼]

Afin d’analyser l’effet de la cystéamine sur la maturation et la fécondation des ovocytes équins nous avons collecté des ovocytes par ponction folliculaire transvaginale échoguidée. Les ovocytes ont été cultivés in vitro pendant 30 heures, puis transférés dans l’oviducte de juments receveuses inséminées. Nous avons utilisé le stade nucléaire après maturation in vitro comme critère de maturation nucléaire et les taux de production d’embryons après transfert d’ovocytes comme critère de maturation cytoplasmique. Contrairement à ce qui a été observé dans d’autres espèces, aucun effet positif de la cystéamine sur la maturation in vitro n’a pu être démontré par notre protocole. D’autres travaux sur les effets de la cystéamine et sur les mécanismes de la maturation in vitro des ovocytes équins sont nécessaires. [less ▲]

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See detailOrigine des troubles morphosyntaxiques chez des enfants dysphasiques
Maillart, Christelle ULg

Doctoral thesis (2003)

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See detailL'hypnose en Anesthésie-Réanimation, de l'application clinique aux mécanismes cérébraux
FAYMONVILLE, Marie-Elisabeth ULg

Thèse d’agrégation de l’enseignement supérieur (2003)

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See detailModélisation de la répartition dynamique des produits phytopharmaceutiques sous une rampe de pulvérisation
Lebeau, Frédéric ULg

Doctoral thesis (2003)

A mathematical model aimed at estimating the distribution of spray deposits of phytopharmaceutical <br />products under a spray boom is proposed. It focuses on the need to take account of the dynamic ... [more ▼]

A mathematical model aimed at estimating the distribution of spray deposits of phytopharmaceutical <br />products under a spray boom is proposed. It focuses on the need to take account of the dynamic effects of <br />the forward movement of the boom. These are related both to the horizontal and vertical boom <br />movement and to the influence of aerodynamical factors on the nozzle spray distribution. <br />The model allows one to compute the spray deposits distribution by multiplying the nozzle spray <br />distribution by the time needed to move from one position to the next. Mathematically, this is expressed <br />by a convolution of the trajectory with the nozzle spray distribution. <br />The model is validated through a dynamic test bench aimed at reproducing the boom movements <br />observed in the field. The chosen method to measure spray deposits distribution is a chemical dosage of <br />the sprayed KCL solution collected in Petri dishes. This method is accurate if the spacing between <br />collectors is small enough. With constant speed and height, the longitudinal variability approaches 5 % <br />and the transversal spray deposits distribution is a function of the nozzle characteristics (as measured on <br />the static spray patternator) and of the nozzle speed. <br />A Pulse Width Modulation (PWM) nozzle boss fitted on the test bench is used to generate a dynamic <br />spray deposits distribution from which the dynamic bidimensional nozzle spray pattern is reconstructed. <br />This dynamic nozzle spray pattern introduced in the model allows a far better estimation of the spray <br />deposits distribution to be made than the one obtained using the static nozzle spray pattern computed <br />using filtered back-projection. <br />The use of the model for estimating the spray deposits distribution under a crop sprayer allows one <br />to identify the influential parameters and to calculate the dosages according to specific local <br />circumstances. Statistical parameters aimed at characterising the treatment quality are proposed. [less ▲]

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See detailStudie zur sonographischen Anatomie des Hufgelenks und der Hufrolle beim Pferd - ein Beitrag zur Diagnose der Podotrochlose
Schneider, Nicole ULg

Doctoral thesis (2003)

Ultrasound is becoming more common in the examination of the coffin joint and podotrochlear apparatus in horses. Purpose of this study is an approach to ultrasound anatomy of the coffin joint and ... [more ▼]

Ultrasound is becoming more common in the examination of the coffin joint and podotrochlear apparatus in horses. Purpose of this study is an approach to ultrasound anatomy of the coffin joint and detectable associated structures. Ultrasound is compared to photographs of dissected limbs to prove sensibility and reliability. Anatomy, artefacts, methods and other difficulties concerning realisation during an ultrasound imaging procedure of the distal interphalangeal joint and podotrochlear apparatus are discussed. This study is based on ten physiologic and seven pathologic reference sonograms, selected from patients at the Ecole Nationale Vétérinaire d’Alfort and the faculty of veterinary medicine of the university of Liège. Transcuneal views of the podotrochlear apparatus of an 18 months old foal have been established post mortem at the institute of veterinary diagnostic imaging at Liège. Modus of registration is real-time-motion, linear and sectorscanners working with 7,5 MHz are used. Echoanatomic documentation shows most of the soft tissue structures in the equine pastern in a reliable and sufficient way, some examples of pathologic alterations detected by ultrasound demonstrate that it is a suitable method to enrich informations achieved by common imaging procedures at the distal region of the equine limb. [less ▲]

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See detailNear Optimal Closed-Loop Control. Application to Electric Power Systems
Ernst, Damien ULg

Doctoral thesis (2003)

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See detailChanger l’organisation du « système » TRM* en radio-oncologie par l’introduction d’un apprentissage organisationnel pour faciliter la mise en place des progrès technologiques.
COUCKE, Philippe ULg

Master of advanced studies dissertation (2003)

Le service de radio-oncologie est caractérisé par la technicité et la complexité toujours en évolution de la prise en charge thérapeutique. Le développement dans ce domaine est tel que le service de radio ... [more ▼]

Le service de radio-oncologie est caractérisé par la technicité et la complexité toujours en évolution de la prise en charge thérapeutique. Le développement dans ce domaine est tel que le service de radio-oncologie risque très rapidement d’être déphasé par rapport à la qualité de la prise en charge que le patient est en mesure d’attendre dans les limites des ressources disponibles. Si l’organisation n’est pas apte à prendre en compte la nécessité d’une amélioration continue, nous ne serons plus capables d’assurer des soins de haute qualité auquel le patient a droit, et nous perdrons rapidement l’habilité technique dans la pratique des soins. Afin d’assurer la maîtrise et la pérennité d’une prise en charge de haute qualité nous voulons mettre en route une démarche globale d’amélioration continue qui doit finalement aboutir à une démarche de projet de qualité et de certification. Nous faisons le constat, aujourd’hui, que le groupe des techniciens en radiologie médicale* ne répond pas aux critères d’une organisation apprenante qui est une condition sine qua non pour l’amélioration continue. Afin de modifier cette situation, il nous faut définir un facteur suffisamment puissant pour déclencher cet évolution d’état d’esprit. Ce changement sera abordé par la mise en place d’une mesure de satisfaction au sein même du système TRM en collaboration avec la cellule ESOP de l’Institut Universitaire de Médecine sociale et Préventive (IUMSP). Cette démarche basée sur un « brainstorming » dont la trame de réflexion pourrait être l’évaluation du niveau atteint dans la pyramide de satisfaction de Maslow par les TRM (analyse interne du système). Ce genre d’exercice effectué par les TRM pourrait aboutir à une visualisation structurée de la problématique du manque d’amélioration continue et des causes de l’absence d’une telle organisation apprenante en utilisant la technique du diagramme d’Ishikawa. L’avantage de cette démarche, c’est que le groupe TRM en tant que tel va aboutir à l’élaboration active d’un certain nombre d’idées clés censées amener une solution aux problèmes énoncés. En même temps nous voulons déclencher une redéfinition de la vision d’entreprise et des tâches et des compétences requises (une formulation claire des exigences en termes qualitatifs et quantitatifs de l’attente du service vis-à-vis des TRM) ; cette tâche incombe aux mandataires du changement c’est-à-dire les médecins et le groupe des physiciens qui font partie de l’environnement immédiat du système TRM, et qui ont besoin d’une amélioration continue du savoir (savoir, savoir être et savoir faire) des TRM afin de pouvoir implémenter des nouvelles techniques complexes en radio-oncologie. Cette « analyse externe » va permettre de définir des objectifs clairs et une vision commune. Le constat de la différence entre l’analyse externe et interne doit aboutir à un travail de groupe mixte (TRM et mandataires) afin de déboucher sur une concordance des deux visions. Afin de faire participer les TRM à l’élaboration des idées-clés des solutions, la mise en place desdites solutions et l’évaluation de l’efficacité des solutions mises en place, nous prévoyons de créer différents groupes de travail ayant chacun un objectif clair et précis (exemple : mise en place de l’utilisation en routine de l’imagerie portale pour le contrôle de qualité systématique des champs d’irradiation). Cette démarche va provoquer un changement fondamental dans le système TRM, une évolution d’une organisation primaire vers une organisation secondaire travaillant par objectifs, plus apte à s’adapter aux exigences de l’environnement, capable d’anticiper et non pas de subir les mises à jour technologiques. Par la même occasion, cette démarche une fois amorcée va obliger l’intégralité du service de radio-oncologie à établir un référentiel d’auto-évaluation et un guide des procédures qui vont permettre à terme d’aboutir sur une certification ISO 9001-2000. *Le genre masculin du titre professionnel s’entend bien entendu également au féminin. [less ▲]

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See detailAn observational study of line-profile variable B stars
Briquet, Maryline ULg

Doctoral thesis (2003)

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See detailClonage, caractérisation et étude de la régulation transcriptionnelle du gène Aox1 encodant l'oxydase alternative chez Chlamydomonas reinhardtii
Baurain, Denis ULg

Doctoral thesis (2003)

Au sein de la membrane interne des mitochondries, quatre complexes multiprotéiques sont impliqués dans le transfert des électrons depuis les équivalents réducteurs jusqu'à l'oxygène moléculaire. L'énergie ... [more ▼]

Au sein de la membrane interne des mitochondries, quatre complexes multiprotéiques sont impliqués dans le transfert des électrons depuis les équivalents réducteurs jusqu'à l'oxygène moléculaire. L'énergie associée à ce transport au travers des complexes I, III et IV est couplée à la synthèse d'ATP par l'intermédiaire d'un gradient de protons. Chez les plantes supérieures, de nombreux champignons et quelques protistes, une seconde voie de transfert diverge de la voie principale au niveau du pool d'ubiquinone, celui-ci étant alors oxydé directement par l'oxygène moléculaire. Lorsque les électrons empruntent cette voie alternative, deux sites d'éjection de protons sont court-circuités et l'énergie produite est dissipée sous forme de chaleur. Cette réaction est catalysée par une enzyme unique, l'oxydase alternative (AOX), souvent encodée par une petite famille multigénique chez les plantes supérieures. Une activité accrue de la voie alternative est observée suite à divers stimuli développementaux et environnementaux, en particulier en conditions de stress. Cette augmentation d'activité résulte d'une activation transcriptionnelle du gène Aox et/ou de modifications post-traductionnelles de la protéine mature. L'AOX de l'algue verte unicellulaire Chlamydomonas reinhardtii est encodée par deux gènes différents, Aox1 et Aox2, le premier étant beaucoup plus transcrit que le second. Les cDNAs Aox1 et Aox2, de même que la séquence génomique Aox2, ont été isolés et caractérisés dans notre laboratoire. Dans un premier temps, nous avons entrepris le clonage et la caractérisation de la séquence génomique Aox1, ce qui nous a permis de comparer sa structure avec celle de son homologue Aox2. Ensuite, afin d'étudier sa régulation transcriptionnelle, nous avons fusionné un segment de 1,4 kb contenant la région promotrice Aox1 à la région codante du gène (Ars) de l'arylsulfatase et mesuré les activités ARS dans des transformants porteurs de la construction chimérique. Nous avons ainsi montré que le promoteur Aox1 est insensible à la plupart des inducteurs classiques de l'AOX, parmi lesquels des agents de stress, des inhibiteurs respiratoires et des métabolites. En revanche, l'expression du gène Aox1 répond à la nature de la source d'azote, sa transcription étant réprimée par l'ammonium et stimulée par le nitrate. De plus, en milieu contenant du nitrate, l'inactivation de la nitrate réductase (première enzyme de la voie d'assimilation du nitrate) conduit à une expression du gène Aox1 encore plus importante. Nous avons en outre observé que cette stimulation par le nitrate se répercute aux niveaux protéique et respiratoire. Une étude de délétion de la région promotrice Aox1 indique qu'un segment court (de −253 à +59 par rapport à l'origine de transcription) est suffisant pour assurer la transcription et la régulation du gène, mais que son expression maximale requiert également des éléments distaux. Aucun motif nucléotidique susceptible d'intervenir dans l'expression du gène Aox1 n'a été identifié à l'issue d'une analyse bioinformatique du promoteur. L'effet de la nature de la source d'azote sur l'expression de l'AOX est interprété sous l'angle d'une optimisation de la synthèse d'ATP mitochondrial sans modification de l'activité respiratoire, en relation avec un possible accroissement de la production d'ATP photosynthétique lorsque le nitrate est utilisé comme source d'azote. [less ▲]

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See detailSome wavelet applications to signal and image processing.
Charles, Catherine ULg

Doctoral thesis (2003)

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See detailLa commercialisation des produits éthiques: études de cas dans les secteurs de l'alimentation bio et équitable
Mouchamps, Hugues ULg

Master's dissertation (2003)

Social enterprises commercializing ethical products present shortcomings in their marketing strategies, especially in the place and promotion dimensions.

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See detailEssais de purification de l'insulin-like growth factor binding protein-3 (IGFBP-3) bovine
Colinet, Frédéric ULg

Master of advanced studies dissertation (2003)

Animal productions are the results of interactions between the genetic potential of the animal, environmental factors and nutrient supplies. These interactions modulate the endocrine system, especially ... [more ▼]

Animal productions are the results of interactions between the genetic potential of the animal, environmental factors and nutrient supplies. These interactions modulate the endocrine system, especially the somatotrope axis. IGFBP-3 is the major carrier of the IGFs (the main growth-promoting peptide) in plasma circulating as part of a 150 kDa ternary complex with one IGF peptide and a single acid-labile subunit. The IGFBP-3 purification would allow the measure of the changes in plasma IGFBP-3 throughout the day and the development and in various physiological situations. We try to purify the bovine IGFBP-3. Firstly, we load 0,5 ml of serum onto an Hiload 16/6 Superdex 200 prep grade column, then onto an ion exchange column and finally onto an IGF-I affinity column. The purification fails perhaps because the sample is to small. Secondly, 5 ml of serum is fractionated by 3 gel filtrations. Between the first and the second filtration, the fractions containing IGF-I binding activity are pooled and concentrated. Before the third gel filtration, the fractions containing this activity are pooled anew, acidified with HCl and incubated at 4 °C for 2 hours. The third gel filtration fractions are pooled and subjected to an heparin-affinity chromatography. The elution pic shows only IGFBP-3 activity. In conclusion, our purified product contains other proteins. But the ternary complex is dissociated, so an IGF-I affinity chromatography would purify the IGFBP-3 from the elution pic of the heparin-affinity column. [less ▲]

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See detailContribution à la mise au point d'une méthode de lutte biologique contre la maladie des pourritures de la couronne de la banane
Lassois, Ludivine ULg

Master's dissertation (2003)

The antagonist activity of two yeast strains (Pichia anomala K strain and Candida oleophila O strain) against the parasitic complex responsible for crowns rot of banana has been evaluated. Their ... [more ▼]

The antagonist activity of two yeast strains (Pichia anomala K strain and Candida oleophila O strain) against the parasitic complex responsible for crowns rot of banana has been evaluated. Their efficiency has been tested on three separated fungi : Colletotrichum musae, Fusarium moiliforme, Cephalosporium sp. and on a parasitic complex formed by the association of these three fungi. Antagonist effects have been observed both on the two first fungi and on the complex. Strain O added at 108 ufc/ml on crowns which were previously inoculated with the complex showed the highest protection (56,0 %). This protection was superior to those observed against the fungi inoculated separately. The influence of the time between the addition of the O strain (108 ufc/ml) and the inoculation of the pathogens on the level of protection has also been measured. It appeared that protection by the O strain was remarkably reinforced when the strain was added 24 hours before the complex (57,0 %). This, in comparison with the additions performed 15 minutes or 3 hours after the pathogens inoculation. The utilisation of the O strain at 108 ufc/ml has been combined with the utilisation of 50μm polybags. These latter allow the formation of a modified atmosphere during the length of the bunches transfer. The protection level was at 61,0% when both methods were combined whereas protection by the yeast alone was of 41,0%. A strict correlation between the severity of the symptoms and the protection by the yeast has been highlighted. When the severity of the disease increases, protection by the yeast decreases. [less ▲]

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See detailEtude génétique Viola calaminaria (Dc) Lej. à l'aide de marqueur moléculaire du type RAPD
Bizoux, Jean-Philippe ULg

Master of advanced studies dissertation (2003)

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See detailEjections de matière par les astres : des étoiles massives aux quasars
Hutsemekers, Damien ULg

Thèse d’agrégation de l’enseignement supérieur (2003)

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See detailAlgorithmes de contournement de barrières
Briquet, Cyril ULg

Master of advanced studies dissertation (2003)

GIS (Geographical Information Systems) bring an ever increasing range of solutions to decision makers seeking ever more accurate situational awareness in the issues they are facing. In particular, a GIS ... [more ▼]

GIS (Geographical Information Systems) bring an ever increasing range of solutions to decision makers seeking ever more accurate situational awareness in the issues they are facing. In particular, a GIS can provide a broad range of visual information resulting from computations that may be complex. These require to develop and implement efficient algorithms because of the massive amount of computations or data that are induced by the geographical nature of the processed data. The Urban and Rural Planning and Study Lab of University of Liege seeks to compute accessibility profiles for so-called "slow transport modes" in the Walloon Region. In this context, a relevant issue of computation of a socio-economical index based on spatial and population data is considered. The objective of this work is to modelize a problem of computation accessibility index, then solve it. The central part consists of the developement of a consistent and efficient algorithm chain to compute optimal shortest paths in geographical zones by avoiding barriers. The integration of the involved algorithms as well as the exploitation of intermediary results are fundemental aspects of the proposed solution. Two variants of the problem are modelized: DLOSP (Discrete Line-Of-Sight Paths, that does not take barriers into account) and DGSP (Discrete Geodesic Shortest Paths, that takes barriers into account). The detection and indexation of the barrieres, the refitting of the considered search space, the optimization of visibility requests and the computation of shortest paths constitute the main steps of the proposed algorithm chain. A distributed computing setup, naturally stemming from the structure of the problem itself, is briefly presented. [less ▲]

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See detailDroes
Verwilghen, Denis ULg

Master's dissertation (2003)

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See detailL'alliance délicate de la gestion forestière et de la biodiversité dans les forêts du centre du Gabon
Doucet, Jean-Louis ULg

Doctoral thesis (2003)

Afin de garantir une exploitation durable de leurs forêts, la plupart des pays d’Afrique centrale ont récemment adapté leur législation forestière. Contraints de suivre cette évolution, les exploitants ... [more ▼]

Afin de garantir une exploitation durable de leurs forêts, la plupart des pays d’Afrique centrale ont récemment adapté leur législation forestière. Contraints de suivre cette évolution, les exploitants forestiers se sont impliqués dans la conception de plans d’aménagement durable. Malheureusement cette « durabilité » se réduit généralement à une production soutenue sur une seule rotation, soit une période d’une trentaine d’années. L’approche proposée ici vise à assurer une exploitation réellement durable par la prise en compte de deux facteurs fondamentaux : la diversité végétale et la dynamique des populations des essences commerciales. [less ▲]

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See detailEléments traces métalliques dans les sols. Contribution à l'étude de leur déterminisme spatial en Région limoneuse belge.
Colinet, Gilles ULg

Doctoral thesis (2003)

The natural background levels of metallic trace elements (MTEs) in cultiva-ted soils should be known in order (i) to understand the processes in which MTEs are involved and (ii) settle a reference system ... [more ▼]

The natural background levels of metallic trace elements (MTEs) in cultiva-ted soils should be known in order (i) to understand the processes in which MTEs are involved and (ii) settle a reference system dedicated to the the ap-praisal of agricultural practices, to the detection of contaminations, or to the time-course follow-up of regional values. A methodological framework has thus been set up to evaluate the importance of natural driving factors, the pe-dogeochemical background, of the spatial distribution of MTEs in soils and also to compare the current levels of MTEs content in agricultural soils from the Loamy Region with natural values. As main results from the study of parent materials, (i) lithological units are now characterized with element content signatures, (ii) the prominent part of clay, total iron, and total aluminium contents as driving factors of the content in MTEs has been measured, and (iii) the geographical homogeneity as well as the absence of spatial continuity of the cover loessic parent material have been showed up. The relations between MTEs and driving variables have been confirmed through the study of the influences of pedogenesis factors on the vertical and lateral differenciations of MTEs content in soils. It was also demonstrated that taking into account the natural volumes of soils when sam-pling facilitates the interpretation of the results and allows finer estimations of the MTEs content, even in homogeneous context. The reference values about natural and usual content in MTEs for various soil horizons that are proposed reveal a relatively weak level of man-made contamination in the Loamy Re-gion. It has also been shown that a regional reference system dedicated to the detec-tion of local contaminations gains in relevance as it integers ancillary datas as well as the local specificities of small natural regions. The spatial variability of MTEs content has been evaluated through various cartographic approaches which led to the conclusion that the Soil Map of Belgium is an extremely worthy document for geochemical mapping. [less ▲]

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See detailPROTECCIÓN JURÍDICA DEL PATRIMONIO CULTURAL COLOMBIANO. EL PLURALISMO PRINCIPIO ORIENTADOR DE UNA CULTURA DE PAZ
Marquez Guerra, José Francisco ULg

Master's dissertation (2003)

Este trabajo intenta desde una de las múltiples formas posibles abordar el estudio del patrimonio cultural. El primero de sus propósitos es presentar un análisis jurídico sobre el desarrollo evolutivo del ... [more ▼]

Este trabajo intenta desde una de las múltiples formas posibles abordar el estudio del patrimonio cultural. El primero de sus propósitos es presentar un análisis jurídico sobre el desarrollo evolutivo del concepto, su significado, los bienes y valores que comprende y su funcionalidad como crisol de identidades, dentro del marco normativo de la jurisdicción colombiana y el correspondiente régimen que somete el acervo cultural de la nación. El segundo propósito es plantear el pluralismo como principio fundamental que orienta y describe la acción del Estado Social de Derecho hacia el reconocimiento efectivo de las diversidades que conforman el pueblo colombiano. Se intenta demostrar, que la integración nacional sólo se logra cimentando la identidad cultural sobre el diálogo intercultural y la disposición abierta a la interacción con otras culturas dentro y más allá del ámbito Estatal. [less ▲]

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See detailEtude des propriétés de surface d'émulsifiants destinés à la panification
Delacharlerie, Sophie ULg

Master's dissertation (2003)

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See detailApproche expérimentale des comportements d'anti-prédation chez le tilapia du Nil (Oreochromis niloticus): détection and évaluation des risques de prédation par les juvéniles
Delcourt, Johann ULg

Master of advanced studies dissertation (2003)

Les juvéniles de tilapia du Nil, issus de génération successives élevées en pisciculture depuis 70 ans, sont toujours capables de reconnaitre une menace prédatrice. Ils s'avèrent capables d'adapter leurs ... [more ▼]

Les juvéniles de tilapia du Nil, issus de génération successives élevées en pisciculture depuis 70 ans, sont toujours capables de reconnaitre une menace prédatrice. Ils s'avèrent capables d'adapter leurs comportements face à différents niveau de risques de prédations (absence de prédateur, prédateur passif, prédateur actif). Les jeunes adoptent des comportements d'inspection de type "tit-for-tat" lorsque le prédateur est actif. Les effets de l'alimentation et de la taille du banc sont explorés. [less ▲]

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See detailImpacts de l’augmentation de la concentration en CO2 atmosphérique sur la composition de la communauté microbienne en bactéries oxydant l’ammoniac du sol.
Malchair, Sandrine ULg

Master of advanced studies dissertation (2003)

Résumé du mémoire de DEA Il reste, actuellement, peu de doutes quant au fait que le climat à l’échelle de la Terre s’est modifié au XXème siècle. De nombreuses évidences suggèrent que ces changements sont ... [more ▼]

Résumé du mémoire de DEA Il reste, actuellement, peu de doutes quant au fait que le climat à l’échelle de la Terre s’est modifié au XXème siècle. De nombreuses évidences suggèrent que ces changements sont liés aux activités anthropiques qui ont accru la concentration atmosphérique en gaz à effet de serre, notamment celle en dioxyde de carbone. Cette augmentation de la concentration en dioxyde de carbone et les changements climatiques associés entraîneront des réponses complexes des écosystèmes. Bien qu’il soit établi que les microorganismes jouent un rôle clé dans le cycle des éléments nutritifs, les conséquences d’une telle augmentation de la concentration en CO2 pour les microbiota du sol sont inconnues. Le cycle de l’azote est particulièrement digne d’intérêt car l’azote est, après le carbone, l’élément le plus important pour la vie des plantes. La nitrification est l’étape clé du cycle de l’azote. En effet, elle influence la productivité primaire, peut causer l’acidification des sols et le lessivage de nitrates. De plus la disponibilité de l’azote dans les sols est un élément régulateur de l’immobilisation du carbone de l’écosystème dans la biomasse des plantes ou des microorganismes du sol. Ce mémoire étudie la composition de la communauté microbienne du sol en bactéries oxydant l’ammoniac (AOB) sous concentration en dioxyde de carbone ambiante ou élevée afin de vérifier si l’augmentation de la concentration en CO2 affecte la communauté de bactéries oxydant l’ammoniac. Ce mémoire s’intègre dans l’étude de l’effet d’une concentration en CO2 élevée sur la nitrification et la dénitrification potentielle (Carnol et al., 2002). Cette étude a nécessité quelques étapes préalables. En effet, il a été nécessaire de renouveler le stock de clusters contrôle (séquence caractéristique des AOB incluses dans des vecteurs). Ce stock a pu être renouvelé par transformation (électroporation) des cellules d’Escherichia coli. Bien que la migration de ces nouveaux clusters contrôle dans le gradient dénaturant diffère légèrement de celle des clusters de la littérature, nous pouvons affirmer, après séquençage, que ces clusters correspondent à ceux décrits dans la littérature. Ensuite, nous avons appliqué le protocole PCR employé pour amplifier les clusters contrôle à l’ADN extrait à partir de nos échantillons de sol lyophilisés. Il est apparu que les conditions prévalant pour l’amplification des clusters contrôle n’étaient pas applicables à nos échantillons de sol. En effet, des produits aspécifiques se sont formés et le rendement de la réaction était faible. C’est pourquoi nous avons optimisé la réaction de PCR. Les conditions permettant d’atteindre un bon compromis entre l’efficacité et la spécificité de la réaction pour nos échantillons ( en employant les amorces CTO spécifiques des AOB) sont les suivantes : température d’annealing de 59°C, concentration en amorce de 20 pmoles par réaction. Ces conditions conviennent aussi bien pour l’amplification pour l’amplification de l’ADN contenu dans les échantillons que pour celle des clusters contrôle. Enfin, nous avons envisagé l’étude de la composition de la communauté microbienne en AOB à partir des échantillons de sols lyophilisés issus de chambres sous concentration en CO2 ambiante ou élevée. Nous avons testé la reproductibilité des techniques employées c’est à dire celle des extractions d’ADN génomique réalisées à partir de nos échantillons et celle de la PCR ; Nous avons, également, étudié la variabilité de la composition de la communauté microbienne en AOB au sein d’une chambre ; Pour finir, nous avons envisagé l’effet possible de l’augmentation de la concentration en CO2 sur la composition de la communauté microbienne en AOB. Il apparaît que, bien que le rendement des extractions génomiques ne soit pas reproductible, cette différence influence peu le pattern de bandes révélées pour la DGGE du point de vue des clusters dominants. De plus, bien que les amplifications d’ADN par PCR à partir des échantillons soient également variables du point de vue de la spécificité et du rendement, cette différence a peu d’impacts sur le pattern de bandes révélées par la DGGE si la PCR permet une amplification suffisante de l’ADN. Cela montre l’importance de l’optimisation de la réaction avant toute nouvelle expérimentation. On a pu constater qu’il n’y a pas de variabilité de la composition de la communauté microbienne en AOB au sein d’une chambre. Cependant, un changement de la composition de la communauté microbienne en AOB a été observé dans les couches de sol exposées trois ans à une teneur en CO2 élevée. Ce changement n’est pas perceptible pour les couches exposées une seule année au traitement. L’exposition longue à une concentration en CO2 supérieure entraîne la disparition des clusters I, II et III. En conclusion, il a été possible de renouveler notre stock de clusters contrôle. L’ADN cible spécifique des AOB est amplifiable par PCR. Cependant, il apparaît que les protocoles PCR ne sont pas transposables. C’est pourquoi, il est nécessaire d’optimiser la réaction de PCR. Le pattern de bandes DGGE est représentatif de la de la composition de la communauté microbienne en AOB si l’ADN amplifié est en quantité et de qualité suffisantes. Aucune variabilité de la composition de la communauté microbienne en AOB n’a été observée au sein d’une chambre. Une exposition longue à un concentration élevée en dioxyde de carbone, contrairement à une exposition de courte durée, modifie la composition de la communauté microbienne en AOB. [less ▲]

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See detailÉlaboration d'une base de données en vue de l'informatisation du catalogue de la cartothèque de l'Unité de documentation des Sciences de la Terre de l'Université de Liège
Borsus, Olivier ULg

Master's dissertation (2003)

Ce mémoire est destiné à l'Unité de Documentation (U.D.) des Sciences de la Terre de l'Université de Liège et consiste en l'élaboration d'une base de données pour le catalogue de son fonds cartographique ... [more ▼]

Ce mémoire est destiné à l'Unité de Documentation (U.D.) des Sciences de la Terre de l'Université de Liège et consiste en l'élaboration d'une base de données pour le catalogue de son fonds cartographique. En effet, l'interface LIBER utilisée à l'Université ne répond pas entièrement aux attentes de l'U.D en terme de critères de recherche spécifiques aux documents cartographiques. Par conséquent il était nécessaire de réaliser une interface conviviale et pratique pour la recherche et la saisie des références de ces cartes. Le logiciel utilisé est FileMaker Pro 5. Pour faciliter l'utilisation de cette base de données, un thésaurus reprenant tous les pays du monde a été créé. A cette fin, les difficultés dues aux changements de noms régionaux et nationaux résultant des évolutions historiques et politiques au fil du temps ont fait l'objet d'une attention particulière. [less ▲]

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See detailLogique et théorie de la connaissance. Recherche sur la distinction entre idéalité et réalité dans les premiers textes de Heidegger (1912-1919)
Dewalque, Arnaud ULg

Master of advanced studies dissertation (2003)

Comment réconcilier la thèse "logique" de l'idéalité des significations (nécessaire pour combattre le psychologisme) et la thèse phénoménologique selon laquelle les significations sont appréhendées au ... [more ▼]

Comment réconcilier la thèse "logique" de l'idéalité des significations (nécessaire pour combattre le psychologisme) et la thèse phénoménologique selon laquelle les significations sont appréhendées au moyen d'actes psychiques "réels"? [less ▲]

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See detailConception d’un système d’aide à la décision pour le choix d'un scénario sylvicole : Application aux peuplements de mélèze en Région wallonne
Pauwels, Dominique

Doctoral thesis (2003)

A silvicultural decision support system (SDSS) has been developed for pure and even-aged larch stands (Larix sp.) in Walloon Region, where Larix seems to be a species with good prospects in a ... [more ▼]

A silvicultural decision support system (SDSS) has been developed for pure and even-aged larch stands (Larix sp.) in Walloon Region, where Larix seems to be a species with good prospects in a multifunctional management context. It main purposes are: (i) to predict the influence of silvicultural treatments on stand evolution and (ii) to help forest managers compare different scenarios according to preset goals. The SDSS comprises three modules designed for (i) larch growth prediction based on initial tree density, thinning regime and site index (scenarios building), (ii) assessment of a set of indicators describing scenarios and (iii) the comparison of scenarios according to appropriate calculated indicators (Multi-Criteria Decision Making or MCDM approach). Financial, technico-economic and ecological indicators are calculated in order to characterise wood production both qualitatively and quantitatively. One of them also tries to express a risk assessment (windthrow hazard). The MCDM method is based on partial aggregation (Electre III) and is used to compare scenarios according to the indicators. This SDSS is integrated in a user-friendly designed software “MGC_Larch” (Make Good Choice for Larch) that helps managers formulate, evaluate and compare different larch silvicultural scenarios according to their priority goals. [less ▲]

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See detailÉtude paléogénétique du cerf élaphe (Cervus elaphus) au cours de la transition Tardiglaciaire - Holocène ancien du Jura (15 000 – 6 000 BP) : relations entre changements morphologiques, environnementaux et génétiques
Pagès, Marie ULg

Master of advanced studies dissertation (2003)

The Late-Glacial - Holocene transition, around 13,000 to 8,000 years ago, is the world theatre of an ample climatic upsetting associated to a deep change of the landscapes. Around the rock-shelter of ... [more ▼]

The Late-Glacial - Holocene transition, around 13,000 to 8,000 years ago, is the world theatre of an ample climatic upsetting associated to a deep change of the landscapes. Around the rock-shelter of Rochedane, an archaeological site from the French Jura, the climate shifts from peri-glacial to temperate, open environment becomes progressively closed and the faunal assemblages are consequently strongly modified. In order to understand the evolutionary mechanisms implied and their different aspects, a multidisciplinary survey has been led on bones from Red Deer, Cervus elaphus, found in the shelter associated with remains of lithic industry and prehistoric art let by the hunters-gatherers during this unstable time. Isotopic geochemistry has already showed that during this period, the habitat and the diet of deers changed. Moreover, morphological studies is demonstrating that, in the same way, the size of deers seems to decrease. To complete both studies, a palaeogenetic approach was then developed to test two different alternative: do the deers found come from a single population that adapts to new ecological conditions or instead do they correspond to a succession of different populations depending on environmental conditions? The results obtained up to now do not allow to conclude between both hypotheses. However, it was demonstrated that it was possible to access authentic mitochondrial DNA sequences (control region, cytochrome b) from these prehistoric bones and to discriminate the deers of Rochedane to the individual level. Thus, this approach is promising in order to decipher in the future the possible ties between environmental, morphological and genetic changes. [less ▲]

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See detailIl pensiero progettuale: un’analisi critica. Abitare Radical, 1965-1975
Prina, Daniela ULg

Master's dissertation (2003)

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See detailSample size reassessment for continuous data in clinical trials
Donneau, Anne-Françoise ULg

Master's dissertation (2003)

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See detailExperiences sur le comportement collectif et social des robots
Meyer, Patrick ULg

Master's dissertation (2003)

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See detailTomographie à émission de positons : vers une approche plus spécifique des pathologies oncologiques
Hustinx, Roland ULg

Thèse d’agrégation de l’enseignement supérieur (2003)

Detailed reference viewed: 29 (4 ULg)
See detailLeçon publique : "Quorum-sensing chez les bactéries ou quand les bactéries dialoguent"
Mainil, Jacques ULg

Thèse d’agrégation de l’enseignement supérieur (2003)

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See detailOn the Model Validation in Nonlinear structural Dynamics,
Kerschen, Gaëtan ULg

Doctoral thesis (2002)

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See detailContamination and detoxication processes in marine mammals from European coasts
Das, Krishna ULg

Doctoral thesis (2002)

The aim of the present work was to determine the relationships between trace metal levels and different factors such as species, geographic origin, diet, age and general body condition of marine mammals ... [more ▼]

The aim of the present work was to determine the relationships between trace metal levels and different factors such as species, geographic origin, diet, age and general body condition of marine mammals from European seas [less ▲]

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See detailRésolution d'un problème aux limites à frontières libres au moyen d'un algorithme de remaillage adaptatif et anisotrope
Béchet, Eric ULg

Doctoral thesis (2002)

This thesis focuses on the study and development of remeshing algorithms for the simulation of free surface flows in porous medium. This kind of flow is coming up with the mould filling phase when ... [more ▼]

This thesis focuses on the study and development of remeshing algorithms for the simulation of free surface flows in porous medium. This kind of flow is coming up with the mould filling phase when manufacturing composite parts with the RTM process (Resin Transfer Moulding), for which the majority of the applications of this research have been done. Remeshing methods presented here are based on the Delaunay criterion for triangulations. An adaptation for curved surfaces is proposed here. This adaptation avoid to keep the link with an exact representation of the CAD surface, and allows the use of a simple tessellation, instead. In fact, the ability to generate anisotropic surface meshes without keeping the link with the tool used to model those surfaces allows to interface finite element solvers with ease. A first publication has been made, based on this part. For practical problems arising in RTM, the ideas coming from the first part have been adapted to the goal of generating anisotropic elements. Thus, the Delaunay criterion considered here is anisoptropic. In fact, the remeshing method presented in this thesis allows a better simulation of the advancing flow front by using anisotropic elements flattened in the direction of the flow. Thus, the resolution of the flow front is high an shows a smooth and regular front. This was not the case with simulations made on a fixed and isotropic mesh, with the same number of degree of freedom. For the evolution of the free surface in time, a level-set approach was originally combined with the remeshing algorithm in order to control the time step independently to the mesh. A second publication has been based on this part. An adaptation of the remeshing algorithm is proposed for thermal problems in the third part of this thesis. In fact, the remeshing allows a better control of the numerical (artificial) diffusion that arise while solving a transport phenomenon. This diffusion is related to the spatial discretisation step. In the case of RTM it happens frequently, in the vicinity of the flow front and when temperature differ notably to the temperature of the mould and the fibres, that the numerical diffusion is an obstacle preventing to achieve a precise simulation of the thermal behaviour in the mould. Transport equations require also a condition on the time step to stabilize the numerical scheme when solved on an Eulerian grid. A variable time-stepping for the sole calculation of transport phenomenon is proposed. A study aimed to prove the possibility of generating a fixed mesh for the whole simulation is proposed for planar geometries. An error estimator based on the Hessian matrix in pressure is used to generate a mesh that will make the interpolation error uniform in the domain. At the same time, an heuristic is built to stretch elements in function of the successive positions of the mesh, determined a priori. This is improving the approximation of the front that is made during the simulation. Finally, an analytical study of a injection case is done, showing the difficulty to generate a mesh satisfying two conditions : uniformity of the interpolation error, and uniformity of the Courant number (which is shown to minimize the numerical diffusion in transport equations). This work was published in a third article. The last part of this thesis focuses on the application of the error estimator to curved surfaces. The surfaces considered here are discrete, it is necessary to separate the interpolation error from the geometrical error. This is done to avoid useless refinement of the mesh near angles in the geometry. An sample case from industry is studied. This part composes the fourth article. Finally, a discussion on the whole research made in this thesis is presented. [less ▲]

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See detailLes conflits de procédure - étude de droit international privé comparé
Wautelet, Patrick ULg

Doctoral thesis (2002)

The dissertation focuses on multiple (or parallel) proceedings in private international litigation. In international civil disputes it is not unusual that jurisdiction for a particular dispute exists in ... [more ▼]

The dissertation focuses on multiple (or parallel) proceedings in private international litigation. In international civil disputes it is not unusual that jurisdiction for a particular dispute exists in several countries. In that case, each party may be tempted to start litigation in the forum most favorable to it, for example to take advantage of the forum’s more generous recovery rules or the extended possibilities of discovery. Similarly, one party can also choose to initiate proceedings in different countries for the same dispute. The question arises how the legal systems involved will and should deal with such ‘multi-fora’ disputes. The first question addressed is whether and to what extent the international legal community should strive to prevent and/or eliminate such duplicate proceedings. It is undubitable that multiple proceedings could lead to undesirable consequences, such as conflicting judgments. Concurrent jurisdiction also brings about a waste of (scarce) judicial resources, and unnecessary expenses for the litigants. To prevent altogether parallel proceedings from happening however, seems at best utopic or even dangerous. Even if the international community were to achieve a global agreement on a comprehensive set of jurisdiction rules, one cannot imagine that there rules would designate one and only one court for each particular dispute. The desire to concentrate jurisdiction for all related disputes in the hands of one court is indeed but one of the numerous factors influencing the allocation of jurisdiction in international matters. The dissertation therefore undertakes to study the rules and instruments that can be used to resolve parallel litigation once multiple proceedings have been issued. The study learns that courts can adopt a variety of attitudes when faced with parallel litigation. A legal system can decide to ignore altogether the fact that a foreign court is seised of parallel proceedings, relying on the res judicata effect of the first decision to be rendered. It can also decide to abstain from taking up the case in deference to the foreign proceedings. Finally it can try to put an end to the parallel proceedings, by enjoining a party from further proceeding before the foreign court. After an in-depth analysis of these different policies and of the various rules and instruments in which they are embodied, my conclusion is that the preference should be given to mechanisms whereby one court voluntarily declines jurisdiction in favor of the other. The preference I express for a mechanism of ‘international abstention’ is however qualified. Whether or not a court declines jurisdiction in favor of a foreign court, will depend inter alia on the confidence it has that justice will be done in the foreign forum. Even with a minimum level of trust and confidence between jurisdictions, the abstention rule can follow different models, from the continental lis alibi pendens rule, which offers almost automatic priority to the court first seised, to the common law doctrine of ‘forum non conveniens’, where priority goes to the more appropriate forum. Between these two extremes lies a world of nuances. The dissertation therefore attempts to formulate an abstention rule which will reconcile these seemingly opposed visions and explain in which circumstances and under which conditions a court should or can decline jurisdiction in deference to litigation pending before a foreign court. [less ▲]

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See detailNaissance et développement du culte de la Trinité. Etude des manifestations de la dévotion en Lotharingie du IXe au XIIe siècle.
Close, Florence ULg

Master of advanced studies dissertation (2002)

Ce mémoire de DEA consistait en la présentation d'un projet de thèse détaillé accompagné d'une bibliographie exhaustive et en un développement de l'un des points évoqués dans ce projet sous la forme d'une ... [more ▼]

Ce mémoire de DEA consistait en la présentation d'un projet de thèse détaillé accompagné d'une bibliographie exhaustive et en un développement de l'un des points évoqués dans ce projet sous la forme d'une contribution scientifique conséquente (ca. 120 p.), en l'occurence la recherche de l'archétype de l'office de la Trinité attribué à l'évêque de Liège, Etienne (901-920). [less ▲]

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See detailLa rationalisation dans l'industrie belge de l'Entre-deux-guerres
Geerkens Provin, Eric ULg

Doctoral thesis (2002)

L'industrie belge a-t-elle fait, dans la première moitié du XXème siècle, l'expérience de ce qui, dans des pays voisins, a été étudié sous le nom de rationalisation, ou en a-t-elle été empêchée par la ... [more ▼]

L'industrie belge a-t-elle fait, dans la première moitié du XXème siècle, l'expérience de ce qui, dans des pays voisins, a été étudié sous le nom de rationalisation, ou en a-t-elle été empêchée par la prépondérance en son sein d'activités anciennes, nées de la Révolution industrielle? Pour répondre à cette question, ce livre fait le choix de donner un très large aperçu de mesures d'organisation, saisies autant que possible à l'échelle de l'atelier; il prend appui sur le dépouillement de nombreux fonds d'archives d'entreprises et d'une abondante littérature technique, patronale et syndicale. Il s'attache d'abord aux pratiques d'organisation présentées en référence non exclusive à la taylorisation, à la recherche de la fluidité du processus de production et aux techniques de contrôle centralisé des exploitations; il réserve ensuite une large attention à la gestion du facteur humain, depuis la formation et la sélection professionnelles jusqu'à la politique sociale patronale, en passant par la question du commandement. Enfin, il tente de mesurer l'impact du changement organisationnel sur les conditions d'activité des travailleurs, de saisir leurs réactions et celles du mouvement ouvrier organisé. S'en dégage un bilan nuancé de la rationalisation dans l'industrie belge à la veille de la Seconde Guerre mondiale, prenant en compte le poids de la conjoncture, les contraintes structurelles, internes et externes aux entreprises, et le jeu — conflictuel ou coopératif — des acteurs. [less ▲]

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See detailApport de la réaction de polymérisation en chaine dans le diagnostic de l'aspergillose invasive
Hayette, Marie-Pierre ULg

Doctoral thesis (2002)

Les aspergilloses invasives surviennent chez les patients immunodéprimés pour la plupart neutropéniques. leur diagnostic est souvent trop tardif et la mise sous traitement aboutit à l'échec dans plus de ... [more ▼]

Les aspergilloses invasives surviennent chez les patients immunodéprimés pour la plupart neutropéniques. leur diagnostic est souvent trop tardif et la mise sous traitement aboutit à l'échec dans plus de 50% des cas. Aussi, il est nécessaire de développer de nouvelles techniques de diagnostic plus sensibles. Dans cette étude deux volets ont été développés: tout d'abord la mise au point d'une technique de polymérisation en chaîne pour la détection d'ADN d'Aspergillus sp. et son utilisation dans les lavages bronchoalvéolaires. Cette étude a montré que la technique développée était sensible et spécifique mais ne permettait pas de distinguer entre infection et colonisation. La seconde étude a consisté en la mise au point d'un modèle expérimental d'aspergillose invasive sur le lapin, dans le but d'évaluer la détection d'ADN fongique par PCR sur sang périphérique, parallèlement à la détection d'antigène galactomannane sérique par ELISA. Les résultats de cette étude ont montré qu'il était possible de détecter de l'ADN fongique dans le sang mais de façon inconstante et souvent postérieurement à la détection d'antigène galactomannane par ELISA. Cela permet de conclure que la place de la PCR Aspergillus sur sang périphérique reste encore à définir dans le diagnositic des aspergilloses invasives. Cependant elle peut être utilisée en complément d'autres techniques diagnostiques. [less ▲]

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See detailSynthesis and potential of new functional aliphatic polyesters
Xudong, Lou

Doctoral thesis (2002)

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See detailDéveloppement et mise au point d’une boucle d’étalonnage pour vanne de régulation en vue d’une future accréditation
Caprace, Jean-David ULg

Master's dissertation (2002)

This project for the graduation of Mechanical Engineer has been realised in the Laboratory for Hydraulic Research of the Ministry of Equipment and Transport of Belgium. It consisted of the design and the ... [more ▼]

This project for the graduation of Mechanical Engineer has been realised in the Laboratory for Hydraulic Research of the Ministry of Equipment and Transport of Belgium. It consisted of the design and the realisation of a test bench for hydraulic control valves in preparation for qualified calibration (ISO 17025). Enventually measurement of actual flow characteristics will allow to optimise the use of valves in piping systems. The work has been done in several phases: design, study of metrology, study of standards, implementation and finally preliminary tests and results. The dimensioning of the test bench led to the drawings and draughts of all pipe sections and of the rejection canal (valves with diameter from 100 to 300 mm). The prssure drop has also been evaluated over the whole system. Concerning methodology, measuring techniques were identified, sensors and their signal handling units have been chosen and dimensioned: weirs, pressure sensor, torque meter and electromagnetic flow meter. With the aim to prepare the future qualification of the test bench, existing standards were identified and studied. Their recommendations have been applied where possible. Finally the test bench has been constructed, which has been a rich experience because of the many unexpected problems related to technique as well as to methodology. Preliminary test results for the calibration of a butterfly valve are promising. Nevertheless there is still some work to do before calibration can be qualified. Anyhow the data already collected and the many observations done during these tests were a good opportunity to analyse technological problems and standardisation. So this as a whole results in a data package which can be the base for future projects. [less ▲]

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See detailMyoglobinurie atypique chez les chevaux au pré: une série de cas en Belgique
Delguste, Catherine ULg

Master of advanced studies dissertation (2002)

Atypical myoglobinuria in grazing horses was described in United Kingdom and Germany between 1984 and 1996. Fourteen horses were presented at the University of Liège between November 2000 and April 2001 ... [more ▼]

Atypical myoglobinuria in grazing horses was described in United Kingdom and Germany between 1984 and 1996. Fourteen horses were presented at the University of Liège between November 2000 and April 2001, with a clinical history suggesting atypical myoglobinuria. Lesions were similar to those previously described. All horses were at rest and grazing when they developed clinical signs. Three times, the syndrome killed several horses grazing together. Horses were generally found recumbent, nearly or totally unable to stand up. They were presenting tachycardia, polypnoea and myoglobinuria, and died rapidly. When performed, blood analysis revealed severe muscular enzymatic activity rises. Histopathology revealed pulmonary congestion and oedema, and squeletal muscular fibers degeneration, mostly in respiratory and postural muscles. These observations are in accordance with cases of atypical myoglobinuria previously described in UK and Germany. The aetiology of this pathology is still unknown, despite of research attempts. An epidemiological inquiry protocol was developed in order to investigate upcoming cases within the scope of aetiologic research. Atypical myoglobinuria in grazing horses was described in United Kingdom and Germany between 1984 and 1996. Fourteen horses were presented at the University of Liège between November 2000 and April 2001, with a clinical history suggesting atypical myoglobinuria. Lesions were similar to those previously described. All horses were at rest and grazing when they developed clinical signs. Three times, the syndrome killed several horses grazing together. Horses were generally found recumbent, nearly or totally unable to stand up. They were presenting tachycardia, polypnoea and myoglobinuria, and died rapidly. When performed, blood analysis revealed severe muscular enzymatic activity rises. Histopathology revealed pulmonary congestion and oedema, and squeletal muscular fibers degeneration, mostly in respiratory and postural muscles. These observations are in accordance with cases of atypical myoglobinuria previously described in UK and Germany. The aetiology of this pathology is still unknown, despite of research attempts. An epidemiological inquiry protocol was developed in order to investigate upcoming cases within the scope of aetiologic research. [less ▲]

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See detailEtude de l'effet d'un stimulus gravitationnel induit artificiellement sur la formation du bois de tension et du bois opposé dans de jeunes pousses de peuplier (Populus euramericana cv "Ghoy"
Jourez, Benoît ULg

Doctoral thesis (2002)

The tension wood of arborescent dicotyledons can be distinguished by its anatomical, chemical, physical and mechanical characteristics which give to it a specific behavior. In its development interfere ... [more ▼]

The tension wood of arborescent dicotyledons can be distinguished by its anatomical, chemical, physical and mechanical characteristics which give to it a specific behavior. In its development interfere complex mechanisms able to perceive endogenous and exogenous stimuli acting on the cambial zone during the new cell differentiation and maturation. Its particular distribution in the shoot induces a dissymetrical distribution of growth stresses capable to modify their orientation. The supporting thesis of this study maintains the idea of a quantitative responses of the young shoots of poplar which develop under controlled conditions, as a reaction to a gravitational stimulus artificially induced. To demonstrate this, the experimental approach consisted on one hand, to determine the reaction induced by the stimulus in the wood structure. On the other hand, to attempt to establish the existence of a modulation of the shoots reaction in regard of the duration and of the intensity of the stimulus application, while applying increasing levels of these parameters. The anatomical observations were based on microscopic cross sections taken from the base of the shoots. The analysis of these sections were realized using an image analyzing technology. The anatomical modifications induced by the stimulus concern all the elements of the wood structure. They generate repercussions on the physical properties of the wood of micro samples composed exclusively of gelatinous fibers. As the stimulus is applied during increasing duration it appears that the formation of the tissues in the opposite wood and in the tension wood requires a relatively short time of presentation. It shows also the rapidity of reaction of the shoots estimated by the latent period. Short duration events are capable to produce repercussions on the wood structure. The rate of cellular division, more important in the tension wood tissues, as measured on the upper face of a bent axis leads to a pith eccentricity in the shoot. The formation of tension wood, a modification of the secondary growth and the movement of the axis are the major modifications quantitatively linked to the intensity of the stimulus. Moreover, the evolution of the measured parameters demonstrates the existence of a natural equilibrium position of the shoots, different from the vertical position, and to which they attempt to return by an straightening or a sagging motion induced by the tension wood tissue. All these results indicated that tension wood should not be considered as a defect but rather as a efficient mechanism for the shoot allowing adaptation and harmonious development in its own environment. [less ▲]

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See detailStatistical analysis of general practitioner rural database focused on cardio-vascular patients
Magis, David ULg

Master of advanced studies dissertation (2002)

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See detailRésonances et dissipations
Jancart, Sylvie ULg

Doctoral thesis (2002)

The discovery of protosolar disks and exoplanets around several stars has revitalized the research combining mean motion resonances and dissipative forces in the elliptic spatial restricted three-body ... [more ▼]

The discovery of protosolar disks and exoplanets around several stars has revitalized the research combining mean motion resonances and dissipative forces in the elliptic spatial restricted three-body problem. This thesis presents that combination in three different ways. A semi-numerical model simulates the behaviour of test particles under the effects of well- known dissipative forces or generic forces. This model is valid for any orbital eccentricities or inclinations, even at high values, and captures around sym- metric and asymmetric equilibria are reproduced. The most common result is the capture in Kozai resonance. Analytical models have been developed to understand the influence of each particular term in the development of the hamiltonian function. An other faster numerical model allows the possibility of following the evolution of thousands of test particles. This mapping has been applied in the study of the stability of the F-ring of Saturn. [less ▲]

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See detailQualité spectrales des tests standardisés universitaires - Mise au point d'indices édumétriques d'analyse de la qualité spectrale des évaluations des acquis des étudiants universitaires et application aux épreuves MOHICAN check up '99
Gilles, Jean-Luc ULg

Doctoral thesis (2002)

For several decades almost all European university institutions have been faced with a strong increase in their number of students whereas the allocated budgets have not increased in proportion (Gibbs ... [more ▼]

For several decades almost all European university institutions have been faced with a strong increase in their number of students whereas the allocated budgets have not increased in proportion (Gibbs & Jenkins, 1992). The universities of the French Community of Belgium do not escape this heavy tendency: compared with the 1972 situation, the number of students has increased to 150% and, in constant francs, subsidies have remained unchanged (Debry & al., 1998). This situation leads in the first cycles of studies, where the students are most numerous, to a massive use of standardized examinations with multiple choice questions (MCQ) which makes the assessment of great groups of students possible within reasonable time delays. The confidence degrees technique associated to the MCQ makes it possible to bypass the "binary" character of students assessment performance (the selected proposal is either correct, or incorrect) provided that a series of methodological rules are followed called "admissible probability measurement procedures" by Shufford & al. (1966). Among those rules: ask the students to express their confidence in a numerical (probabilistic) scale. The one adopted offers 6 degrees of subtlety: 0%, 20%, 40%, 60%, 80% and 100% of confidence. By inviting the student to accompany his choice by the percentage of chances to be correct he attributes to his answer, we allow more subtleties in the analysis of his performances. At one extreme, the choice of a wrong answer accompanied by the maximal percentage of certainty (100%) presents the worst situation, in which the student provides an erroneous answer by estimating that he has a maximal chances to be correct. On the other hand, the student who answers correctly with a maximal certainty shows an assured performance. Between these two extremes, other zones can be identified in the "spectral analysis" of the performances. Jans & Leclercq (1999) propose a specific terminology. They distinguish "ignorance" (correct answer and weak certainty), from "partial knowledge" (correct answer and average certainty), and "perfect knowledge" (correct answer and high certainty). Such spectral gradations were also considered by these authors in the case of an incorrect answer ("mistaken knowledge" and " fallacious knowledge" or "dangerous knowledge"). Usually, the confidence percentages which accompany the MCQ answers are used to deliver more subtler feedback on each student's spectral performances. The innovative aspect of our approach lies in the fact that we have exploited the confidence percentages provided by the students to provide spectral information on the quality of the questions (as opposed to information on the quality of students performances). Our research thus led to the development of a series of original indices for the analysis of assessments' spectral quality. These spectral indices are intended to be used when the assessor must highlight problematic MCQ and, within those, the proposals which contain anomalies. Our starting intuition for the construction of these new indices is as follows: logically the students who answer a question correctly should provide percentages of certainty higher than the students who answer incorrectly. Thus, for a multiple choice question which functions normally from the point of view of the certainty percentages use, we should observe among the students who choose the correct answer a tendency to answer with higher percentages of certainty and, in parallel, among the students who choose a wrong proposal a tendency to answer with lower percentages of certainty. We will then say that there is "spectral coherence". In the case where this situation does not arise, for example when students choose higher certainty percentages for one of the incorrect answers rather than for the correct answer, we are confronted with a problem of inconsistency in the use of the percentages of certainty, we will then speak of "spectral inconsistency". To measure spectral coherence we created two new types of indices starting from the classical point bi serial correlation coefficient (classical rpbis) calculation principle. Let us recall that in the case of the rpbis, the choices or the rejections (1 or 0) of each proposal of a MCQ are correlated with the numbers of correct answers obtained to the whole test. The classical rpbis makes it possible to evaluate up to what extent each proposed alternatives solutions of each MCQ discriminates the students according to the criterion of the number of correct answers. Logically, one expects that the students who collect a high number of correct answers tend to choose the correct answer for a given question and that the students which collect a lower number have a tendency to choose an incorrect proposal. The two new types of spectral coherence indices of measurement are: (1) the Spectral Contrasted rpbis (rpbis SC) and (2) the Spectral Contrasted rpbis calculated after Turbo analysis (rpbis SCT). During a former research we had already used information related to the confidence degrees to calculate a new type of rpbis, the Spectral rpbis or rpbis S (Gilles, 1998). The rpbis S was developed in order to analyze the tendency to use higher certainty in case of correct answers than in case of incorrect answers. Within the framework of this thesis we propose a first improvement of the rpbis S by implementing a "contrasted treatment" for the MCQ incorrect proposals. We use the name "rpbis SC" to indicate the rpbis S is constructed with a "Contrasted treatment" which consists in the computation of the rpbis SC of an incorrect answer by using the data of the students who choose this wrong response in contrast with the data restricted to the students who choose the correct answer excluding the data from the students who choose an other incorrect answer. The advantage lies in the elimination of the data of the students who have chosen the other incorrect answers. This avoids introducing into the measurement of spectral coherence, the "background noise" generated by the data of the other incorrect answers. The principle of "turbo analysis", consists in operating a selection in the data used for rpbis SC calculation on the basis of the level of realism reached by the students. We can thus increase the reliability of information related to the spectral indices by restricting the data to the students who make less errors in their self-assessments (in their use of certainty percentages). We measure the level of errors of self-assessments made by the students by using the index of realism which varies from 0 to 100 (Leclercq & al, 2000). The name rpbis SCT indicates rpbis SC calculated with a Turbo analysis. The word "turbo" refers to the rise to power of the instrument in terms of the quality of information provided as one restricts oneself progressively to data from sets of students who make less and less errors in their self-assessments. We mention in the index's name the threshold of realism used to select the data. For instance rpbis SCT80 was calculated starting from the data of the students whose realism is equal to or higher than 80 (those who make between 0% and 20% of errors in their self-assessments). The new indices rpbis SC and rpbis SCT, which are in the heart of this research, are designed for the detection of problems located at the "alternatives level" inside the MCQ. We also adapted other spectral indices initially planned for the analysis of students performances so that these indices deliver information on the MCQ performances, at a "question level". On one hand, the index of Realization of the predictions by question (Rq) or the quantity of errors of self-assessment contained in the results for a question and, on the other hand, the index of Centration per question (Cq) or the level of over or under confidence in the results for a question. Lastly, we also measured the level of spectral coherence of a question (NCSq) by taking into account the rpbis SC of the various proposals of a MCQ. The "turbo analysis" principle was also applied to the calculation of these spectral indices. We tried to test these new spectral indices designed for detection of suspect alternatives within suspect MCQ using the data of several thousands of answers and certainty percentages collected during the ten standardized tests of the MOHICAN project (Leclercq & al., 2001). They consisted in ten tests of knowledge of the principal subjects at the level of the end of secondary education which were submitted to groups of students entering first year studies in eight of the nine university institutions of the French Community of Belgium (the number of questioned students varied between 1.392 and 3.846 according to tests). These standardized tests consisted of MCQ for which students were invited to choose one answer and systematically accompany it with a percentage of certainty. The students had, not only to state which was their correct proposal, but also which was the percentage of chances to be correct that they granted to each one of their answers. No academic scores were delivered for these (Check up) MOHICAN tests (each student received a diagnostic feedback and the assessors a global feedback). Anonymity was guaranteed. The choice of the percentages of certainty was thus influenced neither by a scale of tariff of points nor by granting a final score which could have affected the later academic course of the student. The total number of MCQ for the ten MOHICAN tests was 173. For two MCQ among them, the 3rd and the 20th question of the general knowledge test in History and Socio-Economy, the values obtained with the spectral rpbis indicate situations of marked spectral inconsistency, the students tending to give lower percentages of certainty for the answers considered as correct and higher percentages of certainty for the incorrect answers. Studying the proposals of the two problematic MCQ by using the classical rpbis indices, we notice that the two MCQ do not function correctly from the point of view of classical discrimination. When we ask for the opinion of the experts of the contents, they confirm that the two MCQ display problematic results: for one of the questions a wrong proposal could also be regarded as being a correct answer and for the other, there is an error in the encoding of the correct answer. For these two questions there is thus convergence of three different perspectives: (1) that of the classical rpbis, (2) that of the experts and, (3) that of the spectral coherence measured using the spectral rpbis. In the case of the MOHICAN tests, the spectral analysis thus allows to highlight two questions that a more qualitative analysis (posterior opinions of the experts) as well as a classical analysis of discrimination (classical rpbis) also indicate as questions with problems. Does the spectral analysis make it possible to perform better than the classical analysis of discrimination (classical rpbis) for locating the problematic questions and the proposals which contain anomalies? This issue has been tested. We analyzed the 173 MCQ of the 10 MOHICAN tests by using the spectral rpbis (rpbis SC, rpbis SCT80 and rpbis SCT90) as well as the classical rpbis indices. We also reviewed the comments formulated by the experts of the contents in connection with each question. From these analyses it comes out that in addition to the two MCQ already discovered previously, 14 other questions are highlighted. The classical rpbis indicates anomalies in each one of these 14 MCQ. Six MCQ present abnormal values at rpbis SC. Only one MCQ obtains an abnormal rpbis SCT80. No MCQ obtains an abnormal rpbis SCT90. Among these 14 questions, only 3 are pointed as problematic by the experts. With regard to the three questions singled out by the experts, they lead to a set of proposals that only the rpbis SC designates, whereas for the rpbis SCT80 and the rpbis SCT90, they are not highlighted. As far as the classical rpbis is concerned one only of the two problematic proposals for only one of the three questions appears. Therefore, from the point of view of "detection", rpbis SC were more effective to highlight the problems raised by the experts than were the other indices. This analysis shows that the various types of rpbis induce also "false alarms", abnormal values collected by proposals whereas the experts of the contents do not detect particular problems. From this point of view, the rpbis SC, with 7 false alarms, is less effective than the rpbis SCT80 which causes only one of them and less than the rpbis SCT90 which starts none, but rpbis SCT80 and rpbis SCT90 fail by "undetecting" the three questions pointed by the experts. On the other hand the rpbis SC starts less false alarms than the classical rpbis which has 10 false alarms. These qualities of lower "undetection" and less "false alarms" are crucial when the question arises of highlighting a problematic MCQ. When we correct the anomalies contained in certain answers within the MCQ, we can, from now on, not only evaluate the spectral impact of these corrections on the answers ("alternatives level"), but also on the whole question by comparing the values obtained with the indices of NCSq, Rq and Cq before and after changes are operated (at the "question level"). We did this for the two most problematic questions of the general knowledge test in History and Socio Economy and quantified the gains in spectral coherence. The improvement of the spectral coherence of the test was also measured by calculating the average values of the spectral indices at the "question level". These average indices thus made it possible to evaluate the spectral impact on a third "test level" of the assessment. In parallel, we also observed an improvement of the fidelity of the test using the classical Cronbach's alpha coefficient. Using the spectral indices developed within the framework of our thesis and usable with three levels of spectral analysis: "ALTERNATIVES", "MCQ" and "TEST", we open a new way for the analysis of the quality of standardized tests and their regulation. We are now able to evaluate the spectral quality of higher education standardized tests using confidence degrees, to highlight possible anomalies in the questions; and, after corrections, to evaluate the spectral impact of the improvements. This is the main contribution of our thesis to the improvement of procedures that control the quality of standardized tests and, by extension, to the improvement of the reliability of the students scores, which, in fine, constitutes the stake of our edumetric concerns. [less ▲]

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See detailDéveloppement de modèles hydrosédimentaires pour la gestion de grands ouvrages hydrauliques
Dewals, Benjamin ULg

Master of advanced studies dissertation (2002)

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See detailRégulation de l’expression de la nestine par les cellules souches mésenchymateuses en culture
Wislet-Gendebien, Sabine ULg

Master of advanced studies dissertation (2002)

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See detailAspects de la toponymie des royaumes polynésiens d’Alo et de Sigave (îles Futuna et ʹĀlofi)
Delorme, Jérémie ULg

Master of advanced studies dissertation (2002)

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