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See detailThe three-dimensional rectangular Multiple Bin Size Bin Packing Problem with transportation constraints: A case study in the eld of air transportation
Paquay, Célia ULg

Doctoral thesis (2017)

According to the International Air Transport Association and Air Transport Action Group, 51.3 million metric tons of goods were transported by airlines in 2014. To transport luggage, freight and mail ... [more ▼]

According to the International Air Transport Association and Air Transport Action Group, 51.3 million metric tons of goods were transported by airlines in 2014. To transport luggage, freight and mail, special containers, called Unit Load Devices (ULD), are used. The method of loading packages into ULDs represents a key element for cargo safety and aircraft weight and balance, as well as for the economy of airline companies. This thesis aims to solve the problem of packing a set of boxes into containers of various shapes without wasting loading space. The goal is to select the best set of ULDs to pack all the boxes achieving a minimum unused volume. As for all the packing problems, geometric constraints have to be satis ed: items cannot overlap and have to lie entirely within the bins. The richness of this application is to manage additional and common constraints: the bin weight limit, rotations, stability and fragility of the boxes, and weight distribution within a ULD. In practice, this problem is manually solved with no strict guarantee that the constraints are met. First, the problem is formulated as a mixed integer linear program. As this problem is NP-hard, it opens the way to heuristics. A second approach makes use of the formulation to apply three matheuristic methods, combining exact approaches and heuristics. Third, a tailored two-phase constructive heuristic is developed for this speci c problem; it aims to nd good initial solutions in short computational times. These approaches contain parameters that have been tuned using the irace parametrisation technique. For the experiments, several instances have been created on the basis of a box data set which stems from a real world case. [less ▲]

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See detailContribution à l'étude de la diversité des abeilles sociales (Apini et Meliponini) et leurs parasites au Gabon
Fabre Anguilet, Edgard ULg

Doctoral thesis (2017)

Les abeilles sociales Meliponini et Apini (Apidae: Apinae) contribuent à la pollinisation des plantes à fleurs et à l'amélioration des rendements agricoles. Elles font soit l’objet d’un élevage soit d’un ... [more ▼]

Les abeilles sociales Meliponini et Apini (Apidae: Apinae) contribuent à la pollinisation des plantes à fleurs et à l'amélioration des rendements agricoles. Elles font soit l’objet d’un élevage soit d’un pillage pour utiliser les produits de la ruche. La diversité, la répartition et l'abondance de ces abeilles dépendent de l'écosystème dans lequel elles évoluent. Les aspects liés à la diversité des espèces, à la distribution, à la biologie, à l'écologie et à l'abondance des nids de même que la situation des parasites majeurs est peu documentée dans de nombreuses régions en Afrique, dont la région d’Afrique centrale. Au vu des nombreuses activités humaines menées dans cette région et du fait que la perte d’habitat et la prédation des nids par l’homme constituent des menaces pour ces abeilles, il convient d’apporter un éclairage sur ces insectes en Afrique centrale. C’est dans ce but que le présent travail a été réalisé afin de contribuer à une meilleure connaissance des relations entre diversité spécifique, abondance des abeilles sociales (Apini et Meliponini) et le niveau de perturbation de l’habitat au Gabon. De même, une attention particulière a été portée sur la situation des parasites majeurs dans ce pays. Les résultats obtenus ont contribué dans un premier temps à clarifier la taxonomie des abeilles sociales étudiées en Afrique et ont mis également en avant l’effet négatif de la perte d’habitat forestier sur la diversité spécifique et la composition d’espèces. Aussi, les espèces qui semblent être fortement impactées par la perte d’habitat forestier ont été identifiées. L’exploitation forestière sélective n’a pas eu d’effet sur la communauté d’espèces. L’étude sur la densité des nids a montré principalement que la distance au cours d’eau avait un effet significatif sur la présence d’un nid et que la méthode d’inventaire par comptage des nids présente une faible capacité de détection de ceux-ci. Concernant les parasites, l’étude a mis en évidence la présence de deux espèces au Gabon : le Varroa destructor Anderson & Trueman et Aethina tumida Murray. Toutefois, les taux d’infestation restent faibles dans les colonies sauvages étudiées. Concernant la domestication de Meliponula bocandei Spinola, le parasite A. tumida est à l’origine du taux élevé d’échec. L’ensemble des résultats de cette étude constituent une base dans la mise en place d’une stratégie de préservation des communautés d’espèces d’abeilles Apini et Meliponini au Gabon, mais aussi dans le cadre d’une domestication de celles-ci. [less ▲]

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See detailCartographie et propriétés physico-chimiques des argiles de Foumban (Ouest-Cameroun)
Nkalih Mefire, Abiba ULg

Doctoral thesis (2016)

La stratégie nationale de promotion des matériaux locaux pour le développement des infrastructures et de l'habitat nécessite l’acquisition des connaissances scientifiques sur lesdits matériaux. Dans ce ... [more ▼]

La stratégie nationale de promotion des matériaux locaux pour le développement des infrastructures et de l'habitat nécessite l’acquisition des connaissances scientifiques sur lesdits matériaux. Dans ce contexte, les argiles de Foumban et ses environs (Ouest-Cameroun) ont été répertoriées sur le terrain, échantillonnées et étudiées en laboratoire afin d’évaluer leur aptitude dans la fabrication des produits de terre cuite (brique cuite, et tuiles). Les travaux de terrain ont permis dans un premier temps de localiser et de caractériser morphologiquement les formations argileuses de type latéritiques ou hydromorphes dans un rayon de 50 kilomètres autour de Foumban, dans les localités de Koutaba, Bangourain, Marom, NJindare et Njimom. Par la suite, le gisement d’argile hydromorphe de Koutaba a été choisi sur base de son extension latérale et verticale pour une évaluation des ressources. L’estimation quantitative de ce gisement sur un rayon de 2 km avec des pas de 200 m donne un tonnage de l’ordre de 18 216 000. La caractérisation minéralogique à partir des analyses minéralogiques (DRX, FTIR, ATG/DTG et MEB) indique que la kaolinite est le minéral argileux dominant, il est associé au quartz et aux feldspaths. On trouve des proportions variables d’illite, de smectite et aussi de chlorite. Les oxyhydroxydes de fer, d’alumine et de titane sont en trace. L’absence de souffre et de pyrite constituent un avantage sur le plan environnemental. L’étude géochimique montre que la silice, l’alumine et l’oxyde de fer sont dominants. La caractérisation physique donne quatre classes granulométriques avec des proportions variables d’un site à l’autre. L’indice de plasticité faible à élevé révèle le caractère moyennement plastique, plastique à très plastique des argiles étudiées. Ces résultats indiquent que les argiles étudiées sont aptes pour la fabrication des produits de terre cuite. Cependant, les argiles riches en smectite ne pourront être utilisées qu’après traitement par ajout de certains additifs. De même, celles qui sont plus ou moins plastiques pourront être dégraissées ou amendées. Les essais céramiques élaborés par voie sèche sur des cylindres cuits à des températures comprises entre 900-1200°C indiquent que les échantillons de Marom et certains échantillons de Koutaba peuvent être utilisés à l’état brut dans la fabrication des briques cuites pleines et des tuiles. Les argiles riches en quartz et pauvres en éléments fusibles, doivent par contre être amendées pour l'obtention d'un produit fini de bonne qualité à des températures inférieures à 1100°C. [less ▲]

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See detailLe marché, le politique et le réseau : les intermédiaires privés du marché du travail à l’épreuve de l’action publique
Gérard, Julie ULg

Doctoral thesis (2016)

Ce travail de thèse porte sur les enjeux de l’activation en Belgique francophone au sein du segment des intermédiaires privés du marché du travail. Il prend pour objet une mesure d’activation ... [more ▼]

Ce travail de thèse porte sur les enjeux de l’activation en Belgique francophone au sein du segment des intermédiaires privés du marché du travail. Il prend pour objet une mesure d’activation : l’accompagnement des demandeurs d’emploi. Cette mesure vise la réinsertion socioprofessionnelle des demandeurs d’emploi par une lutte contre l’exclusion et un retour à l’emploi. L’analyse de cette mesure d’activation repose sur l’étude approfondie de neuf dispositifs d’intermédiation privée, regroupés en trois catégories heuristiques : les intermédiaires de l’accompagnement vers, dans et après l’emploi. Ces catégories incarnent trois types d’accompagnement mis en oeuvre par les intermédiaires privés. Elles sont étudiées à partir d’une démarche empirique qualitative constituée d’observations (N=368), d’analyses documentaires et d’entretiens semi-directifs (N=95) ainsi que d’un cadre d’analyse général constitué d’une sociologie de l’action publique articulant trois perspectives théoriques : l’analyse des politiques publiques d’emploi ; la sociologie de l’action organisée et la sociologie des marchés. L’analyse montre que l’action de ces intermédiaires se concrétise par l’articulation de trois logiques d’action et de trois effets de trappe provoqués par l’influence de pressions institutionnelles exercées par le contexte social et par l’environnement à l’intérieur duquel la prise en charge des demandeurs d’emploi se réalise. Cette thèse entend ainsi démontrer qu’au-delà des contingences organisationnelles de chaque dispositif et de la marge de discrétion des acteurs en présence, l’action des intermédiaires privés du marché du travail s’inscrit dans un mouvement d’homogénéisation de l’action publique. Cette homogénéisation se traduit en une activité de profilage des demandeurs d’emploi fondée sur de multiples formes d’isomorphisme institutionnel. [less ▲]

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See detailCaractérisation des anomalies fluorées des eaux souterraines du socle Précambrien du Bénin central (Afrique de l’Ouest). Apport des outils hydrogéochimiques, pétrographiques et minéralogiques
Tossou, Yao ULg

Doctoral thesis (2016)

In Benin, groundwater is widely used for drinking-water supply for the populations. In the central part of the country (Département des Collines) characterized by hard Precambrian rocks, aquifers are ... [more ▼]

In Benin, groundwater is widely used for drinking-water supply for the populations. In the central part of the country (Département des Collines) characterized by hard Precambrian rocks, aquifers are unproductive and the water quality is affected by contamination. Groundwater quality problems concern particularly high fluoride concentration (up to 7 m/L) and nitrate concentration (up to 350 mg/L). Dental fluorosis is also endemic in the area. This work aims to explain the hydrogeochemical processes which govern mineralization of groundwater and the origin of high fluoride concentration. It will finally help for a better management and control of this environmental issue. The investigations were essentially based on two complementary approaches: hydrochemistry in one hand and in other hand, petrography, mineralogy and geochemistry study of the crystalline aquifer rock materials. Results show that the water mineralization is dominated by water-rock interaction, including the hydrolysis of silicate minerals. However, external inputs also greatly influence the concentration of certain chemichal elements such as nitrate and chloride. Fluoride concentrations seem to be mainly due to hydrolysis of ferromagnesian minerals like biotite. Ion exchanges (〖OH〗^-/F^-) between groundwater and the rock matrix also contribute to increase fluoride concentrations in groundwater. Geochemical investigations show that in the crystalline rocks constitutive minerals, fluorine concentrations are in the range of 60 - 2900 ppm with an average of 1170 ppm. Similar values were obtained in similar worldwide geological formations characterized by high concentrations of fluoride in groundwater. Several fluorine bearing minerals have been identified, such as fluorite, biotite, muscovite, apatite, amphibole, sphene, allanite were identified the basement rocks. Despite the fact that fluorite and apatite are the fluorine most concentrating minerals, biotite seems to be the most contributing mineral to fluorine content of the crystalline rocks. Furthermore, groundwater samples with high fluoride concentration are located in area which basement rocks have important F concentration and higher alterability index. From a geostatistical modeling of the collected data, decision support tools are proposed. Those tools are maps of spatial estimation of fluoride concentrations and probabilities to exceed the guideline value in the groundwater in Collines Department. [less ▲]

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See detail"'Unreadable' Texts: From the Metaphysical Detective Story to the Metacognitive Mystery Tale"
Dechene, Antoine ULg

Doctoral thesis (2016)

This dissertation aims at establishing the genealogy of a literary genre called the metacognitive mystery tale. Its main goal is to delineate a corpus of texts presenting "unreadable" mysteries which ... [more ▼]

This dissertation aims at establishing the genealogy of a literary genre called the metacognitive mystery tale. Its main goal is to delineate a corpus of texts presenting "unreadable" mysteries which, under the deceptively monolithic appearance of subverting "traditional" detective story conventions, offer a multiplicity of motifs – the overwhelming presence of chance, the unfulfilled quest for knowledge, the urban stroller lost in a labyrinthine text – that generate a vast array of epistemological and ontological uncertainties explored by the genre. The selected corpus, composed of some of the genre's most emblematic avatars as well as of less usual suspects, accounts for the specificity and heterogeneity of authors who, in different but related ways, have addressed a certain number of issues underlying the acquisition of knowledge. Following three major intertextual matrices based on the concepts of the "unreadable" city, the "dark" grotesque and the sublime, respectively, this project brings together texts by writers as diverse as Percy Bysshe Shelley, Edgar Allan Poe, Nathaniel Hawthorne, Herman Melville, Henry James, Horacio Quiroga, Jorge Luis Borges, Franz Kafka, Samuel Beckett, Paul Auster, Iain Sinclair and Roberto Bolaño under the banner of the metacognitive mystery tale. This approach represents an opportunity to gather canonical and barely academically studied works and provide new perspectives on stories dealing with the darker, more anxious aspects of investigations led by defective sleuths. [less ▲]

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See detailSapphire Ultraoptics for Sub-meV 121Sb and 125Te Phonon Spectroscopy
Jafari, Atefeh ULg

Doctoral thesis (2016)

Nuclear resonance scattering of synchrotron radiation enables probing hyperfine interactions and element specific vibrational modes of nuclei that exhibit a Mössbauer transition. A prerequisite for this ... [more ▼]

Nuclear resonance scattering of synchrotron radiation enables probing hyperfine interactions and element specific vibrational modes of nuclei that exhibit a Mössbauer transition. A prerequisite for this method is a monochromator with narrow bandwidth. Silicon, as the most commonly used crystal in monochromators, is not suitable for experiments above 30 keV photon energy. Using a sapphire single crystal in backscattering geometry is an alternative. An x-ray beam with narrow bandwidth can be obtained from a back-reflection with a Bragg angle of a few arcsec to a few arcmin smaller than =2. The development of a sapphire backscattering monochromator with high energy resolution, better than 1 meV, would permit detailed lattice dynamics characterization of novel functional materials. Sapphire is a very rigid material with desirable optical properties, high chemical resistance, and high heat conduction. Crystals of large size with high quality are of interest for many industrial applications, and suited for optics and optoelectronics operating under ambient condition or extreme conditions. The purpose of the work in this dissertation is twofold. First, study the quality of sapphire single crystals by modern high-resolution characterization techniques in order to acquire microstructural information and thereby a better understanding of the origin of lattice defects. The second goal is the study of the lattice dynamics in materials based on tellurium and antimony with Mössbauer energies of 35.49 keV and 37.13 keV using nuclear resonance scattering with energy resolution given by one of the highest quality sapphires. White beam topography of more than thirty crystals, grown at the Shubnikov Institute of Crystallography in Moscow, revealed qualitative information about the distribution of lattice defects of which linear defects, i.e. dislocations, are the majority type. The lowest dislocation density of 10^2 -10^5 cm^-2 was found in C-plane crystals grown by the Kyropoulos and Bridgman techniques. We carried out rocking curve imaging in backscattering geometry to estimate the lattice parameter variation and energy resolution from back-reflections. Minimum variations of the lattice parameters on the order of 10^-8 were observed from spots with an edge length of 0.2-0.5 mm. There are a few spots with such a quality in one crystal which makes it suitable as backscattering monochromator in nuclear resonance scattering or as analyzer in resonant inelastic x-ray scattering. The use of very high energy resolution nuclear inelastic scattering with 0.7 meV at the energy of the nuclear transition in 121Sb and 125Te enables valuable insight into the phonon scattering of thermoelectric materials, that convert heat to prvide electricity and vice versa, composed of Sb and Te. A careful study is done on heat carrying acoustic modes in the partial density of states of (PbTe)mAgSbTe2, so called LAST-m alloys. An impressive mismatch in the phonon group velocities in the 2-5 meV range and di erence in the force constants for the Sb and Te density of phonon states is observed, a phonon mismatch predicted to be responsible for low lattice thermal conductivity in LAST-m. An in-depth understanding of the element-specific dynamic properties of cubic and orthorhombic antimony trioxides was achieved using nuclear resonance scattering with an energy resolution of 1 meV at the nuclear transition energy of 121Sb. A softening of the Sb bonds upon transformation from cubic molecular structured in alpha-Sb2O3 to chain structured orthorhombic in beta-Sb2O3 is observed. Furthermore, results on the lattice dynamics on alpha-TeO2, with quasi molecular structure, demonstrate strong interatomic Te bonds, comparable with the strong bonds in molecular structured alpha-Sb2O3. The nuclear resonance data is complemented with inelastic neutron scattering data that reveals the oxygen vibrational modes. In addition, the experimental results validate the calculations of the vibrational modes in these types of materials and serve as benchmark for the calculation. [less ▲]

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See detailApplication des techniques de photogrammétrie par drone à la caractérisation des ressources forestières
Lisein, Jonathan ULg

Doctoral thesis (2016)

Une gestion raisonnée et multifonctionnelle des forêts n’est possible qu’avec une description à jour de l’état de la ressource naturelle. Les inventaires forestiers traditionnels, réalisés sur le terrain ... [more ▼]

Une gestion raisonnée et multifonctionnelle des forêts n’est possible qu’avec une description à jour de l’état de la ressource naturelle. Les inventaires forestiers traditionnels, réalisés sur le terrain, sont couteux et ne couvrent qu’un échantillonnage de la surface boisée. L’essor des drones civils pour la cartographie a initié une révolution dans le domaine de la télédétection environnementale. La polyvalence et la diversité des systèmes drones sont une aubaine pour la foresterie de précision. Ceux-ci sont utilisés pour la réalisation de cartographie très fine des habitats naturels avec une résolution temporelle et spatiale sans précédent. Nous explorons les possibilités d’utilisation de mini-drones pour la caractérisation quantitative et qualitative de la ressource forestière. Nous nous intéressons en particulier à l’estimation de la hauteur des arbres et à la caractérisation de la composition spécifique au sein de peuplements forestiers. La hauteur de la canopée est une variable dendrométrique de première importance : elle est un bon indicateur du stade de développement des peuplements et intervient notamment dans les estimations de biomasse ou de niveau de productivité. La composition spécifique est une information essentielle en regard des principales fonctions que remplit la forêt (conservation, production, récréation, etc). Nous avons comparé l’estimation de la hauteur des peuplements à partir de mesures LiDAR et celle obtenue par photogrammétrie. Bien que permettant une mesure de hauteur individuelle avec une incertitude de l’ordre de 1.04 m (RMSE) en feuillus, la photogrammétrie par drone sur des zones forestières est systématiquement moins précise que les mesures par LiDAR (RMSE de 0.83 m). Ces résultats sont cependant prometteurs, étant donné que la mesure sur terrain de la hauteur totale des arbres est également sujette à une importante imprécision. De plus, la grande flexibilité que confère les petits drones permet d’acquérir, au moment propice du stade de végétation, et l’information de relief de la canopée, et l’information spectrale. La période de fin de feuillaison, au début du mois de juin, s’est avérée le moment le plus propice à une discrimination automatique de cinq groupes d’essences feuillues (le chênes pédonculé, les bouleaux, l’érable sycomore, le frêne commun et les peupliers). Une erreur globale de classification des houppiers de 16% est obtenue avec des acquisitions monotemporelles, alors que l’utilisation d’images acquises à différentes dates permet encore d’améliorer cette classification (erreur globale de classification de 9% pour la meilleure combinaison de 3 dates). Les contraintes de la législation régissant l’utilisation des aéronefs sans pilote à bord restreignent le champs d’action des drones civils. Ainsi, afin d’assurer une sécurité pour tous les usagers de l’espace aérien, les opérations avec un drone sont limitées sous un seuil d’altitude et à une distance maximale du télépilote, ce qui ne permet pas une utilisation optimale de cette technologie pour la couverture de grands domaines forestiers (plusieurs milliers d’hectares). De plus, d’autres outils de télédétection utilisés en foresterie, tels que le LiDAR et l’imagerie satellite et aéroportée, sont plus compétitifs que les drones dès qu’il s’agit de couvrir de grandes surfaces (plusieurs milliers d’hectacre). C’est pourquoi nous pensons que les drones resterons un outils d’analyse de petites surfaces (dizaines voire centaines d’hectares), plus utiles à des fins de recherches scientifiques qu’à une utilisation en gestion forestière. [less ▲]

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See detailValorisation des variétés de dattes secondaires tunisiennes par l’application de traitement hydrothermique
Mrabet, Abdessalem ULg

Doctoral thesis (2016)

The fruit of the date palm (Phoenix dactylifera L.) is one of the most abundant fruits in the world. Nearly 2,000 cultivars of date palm are known, but only some of them are evaluated for their ... [more ▼]

The fruit of the date palm (Phoenix dactylifera L.) is one of the most abundant fruits in the world. Nearly 2,000 cultivars of date palm are known, but only some of them are evaluated for their performance and their fruit quality. This work is a contribution to give value addition to date palm fruit (flesh and seed), from Tunisian secondary varieties, by studying physico-chemical and techno-functional properties of their heir solid fraction rich in fiber and their fraction liquid and rich in phenol and sugar, obtained after pretreatment. Date fleshes contained essentially 60 % total carbohydrates, 23-27 % lignin and 5-4 % dietary fibers. The rest of the components were lower than 4%, with remarkably low amounts of fat (0.3-0.5%) and phenols (0.04-0.07%). In contrast, the percentage of fat (13-17%) and phenols (1-5%) present in date seeds were of great interest. Due to these amounts of phenols, the antiradical activity of seeds was much higher (131-400 mmol TE/Kg dry weight) than that of the flesh (32-47 mmol TE/Kg dry weight). A pretreatment was tested for the total utilization of these dates. After applying several steam treatments condition, valuable dietary fiber concentrates have been obtained. Their recoveries were very similar for the different assays. Only its granulometry showed differences, increasing the fraction with size lower than 4 mm in more intense treatments. DFC had also a good nutritional quality, with high phenol (4-8%), cellulose (12-20%), hemicellulose (5-22%), protein (9-14%), fat (5-11%) and lignin (44-71%). Treatment conditions had higher influence than date variety in the chemical composition. Study of functional properties of these DFC revealed good water and oil retention capacities (5,37-8.50 g water/g DFC and 7,03-8.74 g oil/g DFC, respectively). Furthermore, DFC had also very high antiradical activity (230-580 mmols Trolox/ Kg FC). Thus, these DFC could be considered as a valuable source of antioxidant dietary fiber. The study of physicochemical characteristics showed that DFC had the highest potential to be used as a food ingredient. As an application, the DFC were incorporated in muffin formulations at levels of 2,5 and 5 %. The addition of DFC slightly influenced the technological characteristics of dough and increased their antioxidant properties compared to control. Study of sensory characteristics revealed that there are no significant differences between control and the muffin with DFC. The only concern about the use of this DFC is that its ratio between insoluble and soluble fiber (IF/SF) is very high, around 19, but the best physiological effects are obtained with ratios 1-2.3. For this reason an enzymatic digestion has been assayed in order to decrease this ratio. The different results have shown that, the amount of SF increased from 1.8% to 6.3%, and the ratio IF/SF changed from 19 to 2-3. Moreover, in addition to an increase in the antiradical activity the SF, gluco-, manno-, and xylo-oligosaccharides were identified, oligosaccharides which has been postulated as prebiotics. The study of the liquid phase, rich in soluble antioxidant (phenols), and sugars, was also necessary for the total utilization of the thermally treated dates. The obtained liquid fractions were characterized and their antioxidant capacity determined. The concentration of total phenols increased, by treatments up to 5311 mg/kg of fresh dates, and their antioxidant activity up to 62.5 mmol Trolox/kg of fresh date. Different phenolic extracts have been obtained from the liquid phase in order to used as a antioxidant in food or nutraceutical formulation. The date phenolic extract were fractionated chromatographically using adsorbent or ionic resins to determine the most active fractions. The phenolic profiles were determined for each fraction, yielding fractions with interesting antioxidant activities with EC50 values of up to 0.08 mg/L or values of TEAC of 0.67 mmol Trolox®/g of extract. In addition, the antioxidant properties on lipophilic matrix of the organic extracts of date were also determined, using vegetable and fish oils, as well as the antimicrobial activity. The result showed a remarkable protection against lipid oxidation in oils, increasing the stability of sunflower oil by Rancimat method by four-fold. In addition, some extracts with interesting antimicrobial effects. [less ▲]

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See detailDEVELOPMENT OF A DISCRETE EVENT SIMULATION BASED TOOL FOR OFFSHORE LOGISTICS IN WIND FARM INSTALLATION
Muhabie, Yohannes Tekle ULg

Doctoral thesis (2016)

The o shore wind energy development has shown a progress in the last ten years. Distance from the coast and the depth of the water are increasing continuously. The transport and installation of o -shore ... [more ▼]

The o shore wind energy development has shown a progress in the last ten years. Distance from the coast and the depth of the water are increasing continuously. The transport and installation of o -shore wind turbines is highly dependent on weather condition at sea. Delaying an activity in the logistics chain could have a signi cant impact on overall project completion. Hence there is a need to have a well-organized and thoroughly analyzed planning of the overall processes starting from the producers sites until the o shore site where the turbines will be installed. The weather conditions and the installation strategies are the major limit factors in uencing the o shore wind farm installations. In this thesis a Discrete Event Simulation (DES) based tool has been developed for o shore logistics in wind farm installation. It takes into account the weather restriction limits (wind speed and wave height), distance matrix, vessel characteristics and installation strategies. The logistics model maps out the activities of the o shore wind farm installations. Both historical and probabilistic weather data approaches have been implemented, analyzed and compared. The results indicated that the probabilistic approach is highly a ected by the random seed numbers used to set up the stochastic behavior of the input variable. Application of the developed tools to real O shore Wind Farm (OWF) con guration illustrated that there is a good agreement between the results obtained from the two approaches. However, it has been identi ed that the probabilistic approach may slightly underestimate the project lead time compared to the results obtained using historical data. Furthermore, weather downtime and sensitivity analysis have been carried out for di erent weather scenarios in order to identify the parameters that a ect the logistic chain signi cantly during the o shore wind farm installation. In this context, it is indicated that the lifting operation (limited by wind speed) causes the highest down time compared to other activities and improving the lifting operations could result in a signi cant reduction (10-15 %) in the overall project completion time. In conclusion, overall analysis indicated that the application of a DES tool improves the decision support system including the planning and control of the logistics processes of the o shore wind farm installation, reducing the associated risks. [less ▲]

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See detailUnreinforced clay masonry structures: advanced characterisation of the seismic behaviour including acoustic issues
Mordant, Christophe ULg

Doctoral thesis (2016)

Unreinforced masonry (URM) is traditionally used in North-Western Europe as load- bearing solution for low- to mid-rise buildings. These regions are characterised by a low- to-moderate seismicity. Hence ... [more ▼]

Unreinforced masonry (URM) is traditionally used in North-Western Europe as load- bearing solution for low- to mid-rise buildings. These regions are characterised by a low- to-moderate seismicity. Hence, the earthquake action has to be considered in the structural design. An adequate consideration of the seismic action requires to properly understand how the URM structures behave under this speci c dynamic action and investigations are still needed in that eld. The in uence of openings and walls perpendicular to the seismic action are two main issues. Moreover, the seismic response of these structures is a ected by technical solutions developed to face the demand in terms of building physics performances. Even though, these solutions are not yet integrated in current standards. This thesis aims at improving the understanding of the seismic behaviour of URM struc- tures using a particular type of masonry bonding, for constructional e ciency purposes. Hollow clay blocks are assembled by thin-bed layered glue-mortar joints and a tongue-and- groove system for the head joints. The consequences of speci c details such as an opening, a perpendicular wall or soundproo ng rubber layers are also studied. Four experimental campaigns are presented. Fourteen URM sub-structures including speci c details are tested in static-cyclic and dynamic conditions. Details of the set-up, instrumentation layout and testing procedures are given. Processing of the data is then performed and conclusions are drawn. Regarding the shake table tests, a general rocking be- haviour strongly dependent on the length of the wall and the presence of rubber, is observed. Recommendations for the consideration of soundproo ng devices and for the openings are proposed. The contribution to the strength of perpendicular walls is also highlighted. Based on the dynamic characterisation of the specimens, equivalent mechanical properties are calibrated thanks to the frequency equation, derived from the Timoshenko beam theory. Two sets of boundary conditions are de ned to t the testing con gurations. The relevance of this theory is assessed and the importance of each term of the equation is discussed. In order to extend the results to complete buildings, the tested specimens are modelled in a software implementing an equivalent frame at the macro-scale. A multi-linear material law is calibrated based on a single specimen chosen as reference, in order to reproduce the experimental force-displacement curve. This law is then used for all specimens built in the same masonry type, independently of their geometry. A good approximation is obtained, even if the consideration of perpendicular walls could be improved. The shear capacity of non-rectangular URM walls depends on the compressive length. Its exact expression is thus developed with due consideration of the perpendicular section. Non linearities are observed due to the presence of the perpendicular section and simpli - cations are made for hand calculations. Both the use of the exact and simpli ed expressions in the assessment of the shear resistance provide results similar to the experiments. Finally, the modelling of the rocking motion is investigated. The walls without sound- proo ng devices are modelled following di erent existing models and their predictions are compared with experimental measurements, showing that masonry cannot be assumed as rigid. A main issue is the handling of the transition with impacts. A new model including two rigid blocks and exible and viscous layers is developed to reproduce the rocking behaviour of walls including rubber layers. In presence of rubber, the URM wall can be considered as rigid and model predictions satisfactorily corroborate the experimental measurements. [less ▲]

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See detailLa faisabilité et l'efficacité du traitement assisté par diacétylmorphine en Belgique
Demaret, Isabelle ULg

Doctoral thesis (2016)

Objective The aim of our research was to assess the feasibility and efficacy of a treatment assisted by diacetylmorphine in Liège. This treatment is offered to persons dependent on heroin who pursue ... [more ▼]

Objective The aim of our research was to assess the feasibility and efficacy of a treatment assisted by diacetylmorphine in Liège. This treatment is offered to persons dependent on heroin who pursue street heroin use despite existing treatments. Methods Data were collected in a pilot project of Treatment Assisted by Diacetylmorphine (TADAM), which took place in Liège from 2007 to 2013. The heart of this project is a randomised controlled trial comparing a diacetylmorphine treatment – limited to 12 months – with existing methadone treatments. A participant was responder if he/she showed improvement on the level of street heroin use, health or criminal involvement. Other researches (mainly based on interviews) were added in order to understand interactions between the trial and its actors: heroin users (included or not-included), neighbours of the DAM centre, the staff of the DAM centre and staff of other institutions who worked with our target group in Liège. Results With the help of the centres, partners of the trial, 74 participants (of the 200 planned) were included and randomised: 36 in the experimental group and 38 in the control group. These participants were dependent on heroin for 20 years on average and had already tried 9 treatments for their addiction(s). At the end of the trial, the number of responders in the experimental group was greater but not significantly than in the control group (p=0.35). However, participants in the experimental group showed greater improvement than in the control group, on the level of street heroin use (p=0.0011) and physical (p=0.043) or mental (p=0.035) health. During the follow-up study, three months after the end of the 12 months of treatment, street heroin use in the experimental group had significantly increased (p=0.0052) and the difference with the control group was no longer significant (p=0.55). Discussion Participants included in the trial were, as expected, persons severely dependent on street heroin, who could not find a solution to their addiction with the existing treatments. Participants in the experimental group decreased significantly their street heroin use. However, in our follow-up study, street heroin use increased significantly in the experimental group 3 months after the end of the diacetylmorphine treatment. In the foreign studies, diacetylmorphine treatment showed greater efficacy compared to methadone treatment for this target group and the improvement was sustained after the trial even when the treatment was stopped, but not when the end of treatment was forced against the will of the patient. Nevertheless, our research showed the feasibility of a diacetylmorphine treatment in Liège and its acceptance by the actors involved in the trial. Conclusion Diacetylmorphine treatment is feasible in Belgium. In foreign studies, it showed more efficacy than methadone treatment and benefits gained with this approach were maintained during years. But these benefits disappear when the end of treatment is forced, against the will of the patient. [less ▲]

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See detailInitiatives populaires de solidarité internationale, des « bonnes intentions » au « professionnalisme » ? Sociologie d’un groupe professionnel à l’aune du sentiment de légitimité, dans une perspective comparative Belgique / France
Godin, Julie ULg

Doctoral thesis (2016)

Alongside established, high-profile non-governmental organisations (NGOs), many individuals decide that they need to “do something” to improve the lives of the people they have met (while travelling ... [more ▼]

Alongside established, high-profile non-governmental organisations (NGOs), many individuals decide that they need to “do something” to improve the lives of the people they have met (while travelling, living in another country or adopting a child, etc.). These people join forces with a small group of friends to set up their own development organisations (referred to hereafter as “popular development initiatives”, or PDIs). At present, one of the major concerns in international development cooperation is to make development workers more professional in the interest of better aid effectiveness. This thesis therefore looks at the discourses and practices of these “ordinary” citizens, in order to highlight their role and to identify key issues for this sector. More specifically, we study the dialectic process by which NGO staff and PDI volunteers build and define their professional and amateur legitimacy as development actors, through the prism of the interactionist perspective of the sociology of professional groups. We also draw on the sociology of public action to consider how public authorities, through their policy tools, influence the responsibility and legitimacy of these actors, the interactions between them, and their mutual recognition. The need for professionalism also stems from demands by local partners in the developing world, so we have taken an interest in their perceptions in the case of Senegal. [less ▲]

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See detailReprésenter la connaissance en linguistique. Observations sur l’édition de matériaux et sur l’analyse syntaxique
Mazziotta, Nicolas ULg

Post doctoral thesis (2016)

In the field of linguistics, knowledge is often represented by the means of edited data (textual editions or structured databases) and diagrams. These representations can be called inscriptions of ... [more ▼]

In the field of linguistics, knowledge is often represented by the means of edited data (textual editions or structured databases) and diagrams. These representations can be called inscriptions of knowledge. They suggest three core questions. First of all, how to read them? The first chapter investigates the conventions at use to represent and organize information in edited data and syntactic diagrams. Secondly, how to choose what has to be inscribed? This chapter focuses on how only a part of data and analyses is represented in the inscriptions. An operation of reduction is always necessary and it accompanies the choices about what has to be represented. The choice of the formal structure used for encoding the inscription acts as a major constraint on what can and what cannot be inscribed. Thirdly, how do inscriptions allow us to discover more? This chapter is centered on the use of diagrams to unveil new knowledge about the facts and the theory. It is also shown that diagrams make it possible to investigate the relationships between formal structures themselves. A fourth chapter investigates digital inscriptions, showing how the use of the computer allows us to reevaluate the answers to all the aforementioned questions. [less ▲]

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See detailMineralogy and crystal chemistry of natural and synthetic uranyl oxysalts
Dal Bo, Fabrice ULg

Doctoral thesis (2016)

Since 1960, the number of described uranyl mineral species has been multiplied by three. To date more than 200 mineral species containing uranium as a main structural element are reported in Nature, and ... [more ▼]

Since 1960, the number of described uranyl mineral species has been multiplied by three. To date more than 200 mineral species containing uranium as a main structural element are reported in Nature, and the crystal structures have been determined and refined for only one third of them. Furthermore, many new uranyl minerals are still reported to data, showing sometimes novel chemical compositions and structural arrangements. The uranium mineralogy is a fascinating subject, and an essential field of research as it contributes to the improvement of the management techniques of nuclear waste. The first part of this work was dedicated to the mineralogical characterisation of uranyl minerals, and especially of the autunite-type minerals, occurring in the Rabejac deposit. Indeed, the identification analyses have shown that many samples contain uranyl arsenates of the autunite and meta-autunite groups. Electron-microprobe chemical analyses performed on these minerals species indicate that the P content in (meta-)zeunerite and (meta-)uranospinite is significant in several samples, confirming the solid-solution series between uranyl arsenates and phosphates. Also, cationic substitutions occurring on the A site were observed, especially in uranospinite samples, in which significant amount of Ca is substituted for Mg. Single-crystal X-ray diffraction experiments have been performed on many members of the (meta-)zeunerite-(meta-)torbernite series, and the crystallographic parameters were put into correlation with the variation of the chemical composition. The crystal structure of arsenuranospathite, the Asanalogue of the Al-bearing uranyl phosphate uranospathite, was solved for the first time, indicating that these two minerals are isostructural (Dal Bo et al., 2015). Also, a structure model is proposed for metauranocircite-I, one of the Ba-bearing uranyl phosphate of the meta-autunite group. Investigations of uranyl mineral samples from other localities have allowed to discover single-crystals of bassetite, one of the Fe end-members of the autunite group. The crystal structure of bassetite was also solved for the first time, and these new structural data were presented in parallel to those obtained on saléeite, the Mg-analogue of bassetite (Dal Bo et al., 2016). Thanks to these new data, a discussion about the mineral hierarchy of the (meta-)autunite group is proposed. In addition, the crystal structure of the rare Al-bearing uranyl phosphate furongite from the Kobokobo pegmatite was determined, showing that this mineral species has unique and novel structural features. This specific study, as well as the redefinition of the structural formula of phuralumite, was the occasion to provide a review about the formation of Al polyhedra clusters in uranyl minerals, and to try to elucidate their physicochemical conditions of crystallisation. Many new crystallographic data were also collected on uranyl minerals for which the crystal structure was already reported in the literature. Therefore, it was possible to confirm the previous studies, or to highlight important discrepancies, especially in the case of the Al-bearing uranyl phosphate phuralumite. The H-bonds networks, which are essential for the stability of the structure, have been established in the structure of the uranyl carbonate liebigite, and in the structure of the uranyl silicates cuprosklodowskite, kasolite and soddyite. The second part of this work was devoted to the hydrothermal synthesis of uranyl oxysalts. The experimental conditions, as well as the chemical systems, were chosen in agreement with the conditions occurring in natural uranium deposits, or in geological repositories. A new compound, Be[(UO2)(PO4)]2(H2O)2.5, has been synthesized at low temperature. This is the third Be-bearing uranyl phosphate reported to date, and its crystal structure is based upon sheets showing the uranophane anion topology, typical of uranyl silicates occurring in the oxidation zone of the uranium deposits. The well-known Ba[(UO2)3(MoO4)4(H2O)](H2O)3 and (NH4)2[(UO2)(MoO4)2](H2O) compounds have been synthesized, and new crystallographic data were collected on them. In addition, it was possible to determine the hydrogen-bonds networks for the first compound, and to redefine the Mo6+ coordination polyhedra in the second one. [less ▲]

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See detailDynamic Modeling of Organic Rankine Cycle Power Systems
Desideri, Adriano ULg

Doctoral thesis (2016)

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See detailL'Afrique centrale: entre traditions et transitions. La mutation des socio-écosystèmes en Afrique centrale
Gillet, Pauline ULg

Doctoral thesis (2016)

The forests of the Congo Basin are among the best preserved areas on Earth. Nevertheless, the factors causing deforestation around the world are also present in this subregion. The forest transition ... [more ▼]

The forests of the Congo Basin are among the best preserved areas on Earth. Nevertheless, the factors causing deforestation around the world are also present in this subregion. The forest transition theory describes how the trend of forest areas decline at national level may precede an increase in these areas. If the effects of the forest transition are well known in terms of forest cover degradation, little is known about the effects of forest transition on socio-ecosystems (SES) (understood as a group of actors with impacts on a group of resources and subject to specific institutions). The general objective of this thesis is to characterize the mutation of socio-ecosystems in the Congo Basin in order to identify dynamic of change of Congo Basin forested SES and their possible futures. The collection of socioeconomic data, focusing on the description of the population, the description of the different activities and incomes, the description of food intake and the access to land and resources, were conducted in three SES with a forest cover gradient, located in Cameroon and Gabon. The results show that the cost price of meals is globally increasing with the loss of forest cover. The share of food intake related to the exploitation of natural resources such as hunting, fishing and gathering decreases in favor of proteins from livestock and agricultural products. This leads to the translocation of demand but also to pressures on other anthropogenic ecosystems. The effects of deforestation are then visible at the local level but also on neighboring areas. The diversity of the game and prey decreases moving towards smaller species with the progression of the forest transition. Consequently, there is a reduction in the proportion of these products in both the food intake and household incomes. This analysis shows a decline in the importance of NTFPs in the production and villagers livelihoods. Slash and burn agriculture is practiced in three SES. If the ratio between fallow period and cultivation period decreases with the forest transition, there is an increase in crop diversification leading to a diversification of the diet. Access to forest resources, agricultural land, markets and an external source of employment condition the village activities. The land potential is made to report levels of ownership and co-management of customary space (Le Roy et al., 1996). During the progression of the forest transition curve, the land potential evolves from relatively loose to privatization and the ability to alienate resources. These important modifications of traditional control systems of the relations between man and resources lead to a more adequate management of some commercial resources value (such as agricultural products or mining resources). But, this process is incompatible with the maintenance of certain ecosystem services like large populations of wildlife preservation. If these results fit rather well with the forest transition curve, this is not the case of all SES in Central Africa. Therefore, we propose to combine some results to reflect significant changes of the qualities of a socio-ecosystem, regardless of forest cover rate. The priority would be to establish a standardized data collection protocol to test sites with different forest cover and located on different trajectories. The use of a socio-economic index would make it possible to predict the evolution of SES under different scenarios, whether linked to global or regional pressures (such as the emergence plans enacted by the Central African States) or in contexts of economic crisis or the introduction of new legislation. [less ▲]

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See detailEvaluation des impacts des projets de développement sur les exploitations agricoles familiales et les ménages de l’ATACORA (Nord-Ouest du Benin)
Tohinlo, Yecy ULg

Doctoral thesis (2016)

This doctoral research aims to contribute to a better understanding of the effects of development projects on the improvement of living conditions and livelihoods of rural households in Benin. It begins ... [more ▼]

This doctoral research aims to contribute to a better understanding of the effects of development projects on the improvement of living conditions and livelihoods of rural households in Benin. It begins with the analysis of development trends in Atacora known about the last three decades. It is focused on matching between the dynamics promoted by intervention devices and those endogenous or emerging to lead a part in the consideration of the productive trajectories and performance of family farms and also in the analysis of effects of development projects on food security, living standards and poverty of rural households. The post-development theories and the various conceptions of poverty have served as a guideline for research work. The intervention mechanisms conducted in Atacora (north-western Benin) by the various cooperations (bilateral and multilateral) between 1990 and 2010 constituted the research object of this thesis. The empirical phase took place in the communes of Cobly (West) and Péhunco (East). These communes were selected from their contrasting agro-ecological and socio-economic situations and socio-economic indicators on the one hand and on the other on a typology of the concentration of development projects and the perception of their effects by local people. A stratified sample of 344 households (respectively 214 in Cobly and 130 in Péunco) was formed for the characterization survey. Later, a thorough investigation on living conditions and livelihood of households followed and involved 208 households (129 Cobly; 79 Péhunco). Finally 16 case studies (8 per commune) were conducted on the trajectories of evolution and accumulation of property and wealth of households and farms. Due to the empirical research, special attention was given to primary data collection which lasted more than three (3) years. Qualitative and quantitative tools (including PSM) were combined for the analysis of collected data through individual and group interviews. Results show that the development interventions do not always promote the endogenous dynamics but they generate and maintain, in rural areas, pathways that allow the integration and participation of producers in the world market for agricultural products. And to benefit from various promotional activities, producers adopt supported crops, this have some positive and negative consequences. The integration and participation of rural producers of Atacora to international trade, promote the increase of production and crop yields while further increasing their dependence on the world prices of agricultural products. So while the income of producers is increasing their vulnerability to food insecurity is also increasing because many of the food crops, already insufficient (because of the share of the cotton planted and the cotton production quotas established by the government) to cover food needs, are substracted from consumption to be sold on the market to meet urgent liquidity needs. Thereby, Atacora's rural households, despite the increase of their food production, suffered a rupture of food stocks resulting to annual food crises of at least 4 months (16 weeks) which strikes indiscriminately both recipient households than non-project beneficiaries. However with the increase of sources and income level of recipient households (36% of households of the study sites), those beneficiaries improve their homes and food consumption and invest more in the education of their children. This marks a significant difference between beneficiaries and non-beneficiaries of development projects. Indeed, installed with the same resources, we counted, in 2014, twice more prosperous households and fewer poor among beneficiaries than non-beneficiaries. Furthermore farms and households beneficiaries of assistance have accumulated and hold more productive assets (land, farm equipment, livestock rearing), economic assets and holdines (transportation measures, housing, plots and houses to rent, etc.) than non-beneficiaries with a highly significant difference at 1%. However the level of improvements and living conditions induced by development interventions are still inadequate and insecure, as reduced to the equivalent adult,income as well as capital show no significant difference between beneficiaries and non-beneficiaries. Thus, households (even beneficiaries) remain vulnerable to crises so that any natural disaster (flood, drought, pest invasion, etc.), illness, injury and death of a member of the household, provokes the rapid degradation of living standards and the fall into poverty. This is compounded by the fact that farms owners’ don’t invest really in the restoration and enhancement of the capital '' land fertility ''; mainly in Cobly where the soil fertility level experienced a drastic decline with a consequent increasing use of chemical fertilizers that degrade the soil structure furthermore. It follows that any action aimed at poverty reduction should allow a sustainable improvement in conditions and livelihoods of rural producers by the preservation and restoration of soil fertility on the one hand and the increased resilience to crises on the other hand. Actions to identify specific needs with measures and solutions adapted to each category of producers and households with mainly particular mechanisms of management and restoration of the fertility of agricultural land shall be considered and implemented. [less ▲]

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See detailCooperative spontaneous emission with quantized atomic motion
Damanet, François ULg

Doctoral thesis (2016)

In this thesis, we present investigations on the cooperative dynamics of (ultra)cold atoms coupled to the electromagnetic field in vacuum. The main objective is to identify the consequences of the ... [more ▼]

In this thesis, we present investigations on the cooperative dynamics of (ultra)cold atoms coupled to the electromagnetic field in vacuum. The main objective is to identify the consequences of the quantization of the atomic center-of-mass motion on the atoms-field dynamics, more particularly the atomic \emph{internal} dynamics including dipole-dipole interactions and cooperative spontaneous emission processes. For this purpose, we derive a Markovian master equation for the internal state of a collection of two-level atoms coupled to vacuum accounting for all effects related to the quantization of their motion. These effects depend on three characteristic lengths that can be tuned experimentally: the interatomic distance $r$, the wavelength $\lambda$ of the emitted radiation, and the typical size $\ell$ of the atomic wave packets. This leads to a rich panel of phenomena depending on the hierarchy between these characteristic lengths. Our master equation provides a unifying picture of the consequences of recoil and quantum statistics (bosonic or fermionic) on both the internal dissipative and conservative dynamics, and applies equally well to distinguishable and indistinguishable atoms. It is valid even beyond the Lamb-Dicke regime, i.e.\ for large recoil effects. We give general expressions for the decay rates and the dipole-dipole shifts entering the master equation for arbitrary motional states, and we find closed-form formulas for a number of relevant states (Gaussian states, harmonic oscillator eigenstates, Bose-Einstein condensates motional states). In particular, we show they can be strongly influenced by the motional state of the atoms, which suggests the possibility to quantum program their internal dynamics through motional state engineering. Based on the derived master equation, we investigate in full detail the super- and subradiance phenomena arising from a collection of indistinguishable atoms. Due to the symmetry (for bosons) or antisymmetry (for fermions) of the global state under exchange of atoms, the internal dynamics is restricted to the permutation invariant subspace whose dimension grows as $N^2$ with $N$ the number of atoms. In this particular case, the master equation involves only three rates: a single-atom decay rate $\gamma_0$, a cooperative decay rate $\gamma$ and a collective dipole-dipole shift $\Delta_\mathrm{dd}$. We solve the dynamics exactly for $2$ atoms, numerically for up to $30$ atoms, and obtain the large-$N$ limit by a mean-field approach. We show that a superradiant enhancement of the radiated intensity is always observed for a sufficiently large number of atoms. As regards subradiance, we show that exact decoherence free subspaces that protect against spontaneous emission through destructive interference of individual spontaneous emission amplitudes exist only in the limit of classically localized atoms, i.e.\ for atoms in infinitely steep traps. We assess the validity of our master equation in the optical domain through the study of the exact atoms-field dynamics. Among others, this complementary approach gives access to the vibrational state populations of the atoms after a photon emission and to the angular dependence of the emission spectrum. It also highlights the complex interplay between the atomic internal and motional states, such as the entanglement transfer that can occur during the collective decay of the atoms. Moreover, it opens the door for the study of the non-Markovianity of the internal dynamics. In conclusion, our thesis provides a comprehensive picture of the consequences of the quantization of the atomic motion on cooperative spontaneous emission processes and contributes to the development of theoretical tools for the study of the internal dynamics of (ultra)cold atoms. [less ▲]

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See detailDevelopment and analysis of low-order models of frame structures under blast loads
Hamra, Lotfi ULg

Doctoral thesis (2016)

The main aim of this thesis is to propose an easy-to-apply tool to assess the level of damage of a structure in which one compartment is subjected to blast loading. This compartment is extracted from the ... [more ▼]

The main aim of this thesis is to propose an easy-to-apply tool to assess the level of damage of a structure in which one compartment is subjected to blast loading. This compartment is extracted from the structure accounting for the interaction with the part of the structure surrounding the loaded compartment, which is assumed to be elastic. Before studying the whole frame structure, the structural elements (i.e. the beam and its adjacent columns) are firstly studied separately taking into account the lateral restraint and mass offered by the indirectly affected part (IAP) of the structure. Secondly, the dynamic behaviour of a simple compartment made of pinned members and laterally braced is investigated. The material laws are assumed to be elastic-perfectly plastic, neglecting the effect of strain rate on the yield strength. The out-of-plane instabilities of the structural members are disregarded. • To explain the context of this study + final aim of this research Two analytical models are developed to predict the dynamic response of the frame beam subjected to blast loading, including the elastic lateral restraint and inertia offered by the IAP of the structure, the development of nonlinear membrane action (P-\delta effect) and also, the interaction between bending moment and axial force in the plastic hinges. The first model is based on a single degree of freedom (SDOF model) which is the transverse mid-span deflection of the beam while the second model is a two-degree-of-freedom (2-DOF) model which also includes the axial elongation of the beam. The accuracy of these two low-order models is assessed with finite element simulations. This validation stage shows that the proposed low-order models capture the physics of the problem in most cases of practical interest. A dimensional analysis of the problem reveals that, under the considered assumptions, four dimensionless parameters mainly influence the required ductility of the beam. Two of them are related to the behavior of the indirectly affected part (the lateral restraint and mass). Another one is related to the mechanical properties of the investigated beam (i.e. the ratio of the bending to axial resistance). The last parameter incorporates scales of the geometry and of the deformed configuration at the onset of the plastic mechanism. Concerning the columns, an analytical model is proposed to assess its dynamic response under constant axial compressive load and lateral blast loading. It accounts for large displacement (P-\delta effect), bending moment-axial force (M-N) plastic interaction as well as its interaction with the indirectly affected part (IAP) of the structure. This model is non-smooth piecewise linear and involves two degrees of freedoms (2 DOFs) in each regime of the motion of the column (related to the possibilities of development of plastic hinges). The dimensional analysis of the problem reveals that, under the considered assumptions, four dimensionless parameters mainly influence the dynamic stability of the beam-column. Two of them are related to the behavior of the indirectly affected part (the lateral restraint and mass). Another one is related to the critical load multiplier (i.e. the ratio of the axial compressive load to Euler elastic buckling resistance). The last parameter is the reduced slenderness of the beam-column. Subsequent to a parametric study, it is demonstrated that a good correlation is found between the results provided by the analytical model and a richer FEM model, despite some little discrepancies observed for some intermediate values of stiffness of the lateral restraint and lateral mass. As a possible improvement, adjustments to the analytical model are suggested. Finally, the dynamic behaviour of a simple frame under constant compressive loads and lateral blast loading is studied with a last 2-DOF analytical model. A multi-layer model of the cross-section of the beam is used to derive the bending moment-axial force (M-N) plastic interaction instead of the Lescouarc'h formula and normality rule. The coupling between the beam and the adjacent columns is ensured through appropriate boundary conditions. For the studied frame, two blast scenarios are contemplated, the first one corresponds to a quasi-static blast loading while the second one refers to a dynamic blast loading. The first case study shows that a very good agreement is achieved between the deflections predicted by the analytical and numerical models although a discrepancy is observed in the assessment of the axial force in the column due to the shape of the inertial force distribution of the beam assumed in the model. The second case study illustrates that, in both analytical and numerical models, the columns are predicted to fail by buckling due to the P-\delta effect although the axial force in the column is again inaccurately captured by the analytical model for the same reason. [less ▲]

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See detailSpace Thermal Analysis through Reduced Finite Element Modelling
Jacques, Lionel ULg

Doctoral thesis (2016)

The finite element method (FEM) is widely used in mechanical engineering, in particular for structure design. However, it is not often exploited for the thermal analysis of space structures for which the ... [more ▼]

The finite element method (FEM) is widely used in mechanical engineering, in particular for structure design. However, it is not often exploited for the thermal analysis of space structures for which the use of the lumped parameter method is still commonplace. To alleviate the computational burden of the FEM for thermal analyses involving conduction and radiation, an innovative global conductive-radiative reduction scheme based on the clustering of the finite element mesh is presented. The proposed method leads to a significant reduction of the number of radiative exchange factors (REFs) to compute and size of the corresponding matrix. It further keeps accurate conduction information by introducing the concept of physically meaningful super nodes associated to the clusters from which are derived the reduced conductive couplings. To complement the reduction of the number of faces, an improved Monte Carlo ray tracing algorithm is developed. It provides better accuracy and convergence rate than the classic Monte Carlo method. The algorithm is adapted to the partitioned FE mesh and includes quadrics fitting for accurate normal representation. The resulting conductive-radiative reduced model is solved using standard iterative techniques and the detailed mesh temperatures, recovered from the super nodes temperatures, can be directly exploited for thermo-mechanical analysis. The proposed global reduction method is validated on several space structures and is benchmarked against ESATAN-TMS, the standard thermal analysis software used in the European aerospace industry. [less ▲]

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See detailApplication des biotechnologies post-récolte pour la valorisation des produits de terroirs marocains par des microorganismes sélectionnés impliqués dans la fermentation de fruits : cas du vinaigre
Mounir, Majid ULg

Doctoral thesis (2016)

Dans cette étude, de nouvelles souches microbiennes (levures et bactéries acétiques) ont été isolées, sélectionnées, identifiées et caractérisées pour évaluer leur usage comme starters pour la production ... [more ▼]

Dans cette étude, de nouvelles souches microbiennes (levures et bactéries acétiques) ont été isolées, sélectionnées, identifiées et caractérisées pour évaluer leur usage comme starters pour la production industrielle de vinaigre de fruits. Dans un premier temps, la levure Saccharomyces cerevisiae YS-DN1 a été isolée à partir de dattes locales et étudiée pour ces pouvoirs de fermentation des sucres et de résistance aux différents facteurs de stress (éthanolique, thermique et osmotique). Cette souche s’est distinguée comme étant la plus performante dans la production d’éthanol en comparaison à deux autres souches industrielles de référence. En effet, YS-DN1 était la seule souche capable de se développer à une température entre 35 et 40°C en présence d’un taux alcoolique élevé (>8% éthanol) et une pression osmotique agressive (>18 °Brix). Dans un deuxième temps, deux souches de bactéries acétiques CV01 et AF01, identifiées par des techniques moléculaires comme étant affiliées à l’espèce Acetobacter pasteurianus, ont été isolées respectivement de cactus et de pommes. A l’issue des caractérisations physiologiques et des cinétiques de fermentation réalisées en erlens et en bioréacteurs (6 L, 20 L et 500 L), ces deux souches ont montré des pouvoirs de thermotolérance et d’acétification notables. L’étude enzymatique réalisée sur les enzymes membranaires ADH et ALDH formant le complexe enzymatique impliqué dans le processus d’oxydation de l’éthanol a révélé que, contrairement aux souches de référence, ces enzymes maintiennent une activité normale à haute température (38°C). L’étude cinétique en bioréacteur 20 L a montré que la souche CV01 était moins sensible à la variation de la composition du milieu de fermentation et a pu produire plus d’acide acétique (10 g/L) que la souche AF01. Durant le même cycle de fermentation, la souche CV01 était notablement la seule souche capable d’orienter son mécanisme métabolique pour la production de l’acide gluconique simultanément avec l’acide acétique. Par ailleurs, la méthode des surfaces de réponse (RSM) a été utilisée pour l’optimisation de la production en biomasse de la souche CV01. Les valeurs optimales des facteurs influents, à savoir l’éthanol, l’acide acétique, le glucose et le pH, permettant d’obtenir le maximum de biomasse cellulaire (2.21 g/L) étaient de 28.18 g/L, 10.12 g/L, 15.15 g/L et 5.33, respectivement. Dans une troisième partie, la souche A. pasteurianus CV01 a été évaluée pour sa capacité à résister aux conditions de stress thermique en bioréacteur. Les résultats obtenus montrent une habilité de cette souche à contrecarrer l’augmentation excessive de température (>35°C) au cours d’un cycle de fermentation sans refroidissement. En outre, un protocole de démarrage de fermentation en mode semi-continu a été proposé et adopté pour la production de vinaigre de fruits en bioréacteur 500 L. La caractérisation aromatique du vinaigre de pomme produit à l’échelle pilote moyennant la technique de l’espace de tête – microextraction en phase solide (HS-SPME) – a permis d’identifier dans la composition de son arôme des molécules associées à des descripteurs généralement appréciés . Ces souches, caractérisées pour leur thermotolérance notable, pourront être utilisées comme starters pour la production à grande échelle de vinaigre de fruits. [less ▲]

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See detailL'art de gouverner les déchets hautement radioactifs. Analyse comparée de la Belgique, la France et le Canada
Parotte, Céline ULg

Doctoral thesis (2016)

Comment l'art de gouverner les déchets hautement radioactifs, tel qu'il a évolué au cours des deux dernières décennies, a-t-il redéfini les enjeux sociotechniques du programme de gestion des déchets ... [more ▼]

Comment l'art de gouverner les déchets hautement radioactifs, tel qu'il a évolué au cours des deux dernières décennies, a-t-il redéfini les enjeux sociotechniques du programme de gestion des déchets hautement radioactifs et réciproquement? Telle est la question qui traverse cette thèse. Combinant l'analytique de gouvernement (Dean 2010) à une approche co-productionniste forte (Joly 2015), trois régimes de pratiques de gouvernement, en France, en Belgique et au Canada sont scrutés et comparés. Cet écrit propose de suivre l'objet, en cinq chapitres, depuis sa définition (au travers des systèmes de classification), en passant par l’élaboration, la mise en oeuvre territoriale et l'évaluation régulière de son programme de gestion. Chemin faisant, nous cherchons à comprendre comment le dépôt géologique est resté l’option de référence clef pour la catégorie "déchet hautement radioactif". Différentes co-productions seront mises à jour révélant l'asymétrie de pouvoir entre les acteurs, la trajectoire (dis)continue du programme et le caractère expérimental de l’art de gouverner les déchets hautement radioactifs. Un art expérimental, dont nous soutenons que les formes peuvent varier, entre autres, selon l'attitude des expérimentateurs. [less ▲]

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See detailActive Network Management for Electrical Distribution Systems
Gemine, Quentin ULg

Doctoral thesis (2016)

With the increasing share of renewable and distributed generation in electrical distribution systems, Active Network Management (ANM) has become a valuable option for a distribution system operator to ... [more ▼]

With the increasing share of renewable and distributed generation in electrical distribution systems, Active Network Management (ANM) has become a valuable option for a distribution system operator to operate his system in a secure and cost-effective way without relying solely on network reinforcement. ANM strategies are short-term policies that control the power injected by generators and/or taken off by loads in order to avoid congestion or voltage issues. While simple ANM strategies consist of curtailing temporary excess generation, more advanced strategies instead attempt to move the consumption of loads to anticipated periods of high renewable generation. Such advanced strategies mean that the system operator has to solve large-scale optimal sequential decision-making problems under uncertainty. The problems are sequential for several reasons. For example, decisions taken at a given moment constrain the future decisions that can be taken, and decisions should be communicated to the system’s actors sufficiently in advance to give them enough time for implementation. Uncertainty must be explicitly accounted for because neither demand nor generation can be accurately forecasted. This dissertation presents various research contributions about ANM for distribution systems. These contributions range from the motivation of using a framework of sequential decision-making under uncertainty to the study of computational methods that implement ANM strategies. A particular emphasis is placed on the formulation of the problem, which ultimately falls within the class of Markov decision processes. The modeling of stochasticity is explored and a novel approach that relies on a Gaussian Mixture Model is presented. Computational methods including several relaxations and approximations of multi-period and multi-scenario extensions of the optimal power flow problem with discrete decision variables were considered. [less ▲]

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See detailEtude de la régulation de l'expression de l'opéron ftsW-psr-pbp5 chez Enterococcus hirae
Maréchal, Maxime ULg

Doctoral thesis (2016)

Les entérocoques sont des microorganismes commensaux du tractus digestif de la plupart des animaux mais sont également des pathogènes opportunistes. Lorsque les entérocoques sont associés à une infection ... [more ▼]

Les entérocoques sont des microorganismes commensaux du tractus digestif de la plupart des animaux mais sont également des pathogènes opportunistes. Lorsque les entérocoques sont associés à une infection, la sélection d’un traitement antibiotique adéquat peut s’avérer difficile. Cela est dû à la résistance, intrinsèque ou acquise, des entérocoques à de nombreux antibiotiques. Dans ce travail, nous nous sommes intéressés à leur résistance intrinsèque aux β-lactamines. Un des mécanismes de résistance envers ces antibiotiques est la production d’un PBP de faible affinité. Cependant, le facteur responsable de la surproduction de cette protéine chez les souches présentant un niveau de résistance plus élevé n’est pas encore connu. Ce travail avait pour objectif principal de contribuer à une meilleure compréhension du mécanisme moléculaire responsable de la résistance aux β-lactamines et d’établir le rôle de l’opéron ftsWpsr-pbp5 chez Enterococcus hirae. La première partie de ce travail a été focalisée sur les protéines codées par les gènes ftsW, psr et pbp5. La publication du premier génome d’E. hirae ATCC9790 nous a permis d’identifier et situer dans le génome d’autres gènes codant pour des protéines de la même famille (SEDS pour FtsW, LCP pour Psr, et les autres PBPs pour PBP5). Nous avons produit et purifié ces différentes protéines avec pour visée principale la possibilité d’obtenir des anticorps spécifiques pouvant servir à localiser les protéines au sein de la cellule d’E. hirae. Nous avons établi que la protéine Psr lie le peptidoglycane, se localise avec PBP5 au niveau du site de division et possède des caractéristiques en accord avec une fonction similaire à celle proposée pour d’autres protéines LCP. La seconde partie du travail était axée sur la sélection et l’étude de nouveaux mutants hyperrésistants aux β-lactamines. L’analyse de leur physiologie, de l’expression du PBP5 et de l’environnement génétique du gène pbp5 chez chacun d’eux a été réalisée. Le séquençage du génome de deux mutants a été effectué afin de pouvoir identifier les mutations présentes permettant leur résistance. Des analyses de la force promotrice des séquences en amont de chaque gène de l’opéron ftsW-psr-pbp5 d’E. hirae ont été menées en utilisant le gène rapporteur de la luciférase de luciole. Ces expériences et les mutations observées chez les mutants, nous ont permis d’identifier des éléments régulateurs qui ont une influence sur l’expression de l’opéron ftsW-psr-pbp5. [less ▲]

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See detailDevelopment of a new design method to define the rotation capacity of steel hollow sections
Saloumi, Elsy ULg

Doctoral thesis (2016)

The present PhD thesis is dedicated to the characterisation of hollow section shapes’ rotational capacity. More precisely, the effort was made towards suggesting new ways to resort to plastic analysis, by ... [more ▼]

The present PhD thesis is dedicated to the characterisation of hollow section shapes’ rotational capacity. More precisely, the effort was made towards suggesting new ways to resort to plastic analysis, by defining a new and accurate proposition to characterise the rotation capacity Rcap of sections, which could be associated with the rotation demand of a structure Rdem. Therefore, the purpose of this thesis is to establish a direct dependence of the rotation capacity Rcap with a newly defined cross-section slenderness CS. Hence, current design standards disregard the rotation demand of the structure and allow plastic analysis based on a plate slenderness limit. To achieve this purpose, an experimental campaign was performed consisting in 23 bending tests on square and rectangular hollow sections tested in bending, in addition to 8 stub columns. Then, a numerical model based on the finite element software FINELg was calibrated to well represent these experimental tests, as well as cold-formed bending tests from literature. Based on these results, a good agreement between experimental and numerical results was shown and the numerical software was therefore validated. Accordingly, since the numerical software was proved to well represent the bending behaviour of hollow beams, around 8000 finite element simulations were performed while varying sections dimensions, material properties and loading configuration. These results reported that actual standards limitations were inappropriate, and stricter values were proposed. Moreover, based on the numerical computations, a continuous curve capable of describing the rotation capacity of sections as a function of the cross-section slenderness was proposed. The production route, loading application and yield strength were identified as key parameters having a major impact on the rotation capacity of sections. Consequently, different curves were proposed for each parameter; based on these curves, the rotation capacity of the section could be compared to the rotation demand of a structure in order to obtain a practical, safe, and reliable design calculation. [less ▲]

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See detailDevelopment of a new design method for steel hollow section members resistance
Hayeck, Marielle ULg

Doctoral thesis (2016)

This dissertation presents research done in the field of enhancing the performance and the carrying capacity of tubular members, through the development of an original design approach based on the ... [more ▼]

This dissertation presents research done in the field of enhancing the performance and the carrying capacity of tubular members, through the development of an original design approach based on the “Overall Interaction Concept” (O.I.C.). The proposed approach makes use of the interaction between the two ideal behaviours of structural members (resistance and instability) and includes the influence of initial imperfections (out-of straightness, residual stresses, non-homogenous material), to calculate the resistance of a structure through a single parameter: “relative slenderness”. A test program was carried out as a part of a European project named ‘HOLLOPOC’ to determine the experimental behaviour of beam-columns loaded by bi-axial bending with axial force. Twelve buckling tests, consisting of hot-rolled and cold-formed rectangular and circular hollow section members were conducted. These tests were accompanied by preliminary measurements of cross-section geometry, material properties, geometrical imperfections, residual stresses as well as stub column tests. Besides, a finite element model was calibrated on the basis of these tests. For both the present test series and another one from the literature, it was shown that the FE models were capable of replicating accurately the response and resistance of the experiments. Accordingly, the validated FE models have been further used in extensive numerical studies, and a database comprising more than seventy thousand results was built consecutively. Based on these computations, design proposals were made, by considering identified governing parameters, within the context of the Overall Interaction Concept, using an extension of the Ayrton-Perry approach. Finally, a safely evaluation was completed to check the proposed formulae against the results of current Eurocode 3 rules. [less ▲]

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See detailContribution to the study of the effect of drying on the nutritive value of corn grain (Zea mays L.) for poultry and pigs feeding
Odjo, Djosse Psijus Sylvanus ULg

Doctoral thesis (2016)

Corn grain (Zea mays L.) is widely produced all over the world and is intensively used in poultry and pigs feeding. Drying with hot air is usually utilized to preserve corn after harvest by decreasing the ... [more ▼]

Corn grain (Zea mays L.) is widely produced all over the world and is intensively used in poultry and pigs feeding. Drying with hot air is usually utilized to preserve corn after harvest by decreasing the water content. During high temperature drying, major components (starch and proteins) of corn grain undergo some structural changes with possible nutritional implication. This thesis aimed at increasing knowledge regarding the effect of the drying process on the feeding value of the corn grain for broilers and pigs feeding. After the general introduction and a review which attempts to summarize the major findings of previous studies carried out on the effects of drying on the nutritive value of corn for broilers feeding, the first in vitro experiment performed aimed to assess the effect of fluidized-bed drying on the digestibility of dry matter, starch and protein using a sequential pepsin-pancreatin protocol. It appeared that when corn grains harvested at similar moisture content are dried at different temperatures, the digestibility of starch and that of crude proteins are not affected in a similar way. Higher drying temperatures increased the final digestibility of starch while the digestibility of crude proteins decreased mainly during the pepsin step of digestion. Differences in the kinetics of starch digestion according to the corn grain temperature were attributed to the structural modifications induced within starch granules and proteins in response to the drying conditions. As the digestion of starch involves the breakdown of glycosidic bonds and results in the production of various oligosaccharides, a second experiment was performed in order to get more insight into the nature of saccharides released after the in vitro digestion of corn grains. Three methods were thus compared in their ability to provide relevant information about sugar saccharides released during an in vitro digestion procedure that mimics the pig digestive model. High Performance Anion Exchange Chromatography coupled with a Pulsed Amperometric Detector was revealed to give the most effective qualitative and quantitative information regarding the digestion of starch. Five major saccharides were found as the result of in vitro pepsin-pancreatin digestion of corn grain: glucose, isomaltose, maltose, maltotriose and glucosyl-maltotriose. The relative concentration of these saccharides varied according to the temperature applied during the corn drying, suggesting that structural changes occurring within starch granules (partial gelatinization) would lead to different digestion profiles in the small intestine and may therefore affect the nutritional physiology in pig intestinal tract. Protein is also affected by the high drying temperature. Among corn protein subgroups, salt-soluble proteins are the most sensitive to heat and their solubility decreases when the drying temperature increases. In a third experiment, the denaturation of salt-soluble proteins during corn drying and hydrothermal treatment was monitored and modelled. The impairment of corn protein solubility in saline buffer was revealed to depend mainly on temperature, time of processing and moisture content of materials treated. The evolution of extractible salt-soluble proteins content of corn kernels during drying at high temperature was more correctly described using the second order kinetic reaction than with the first order kinetic reaction when classical kinetic models were compared. In a forth study the relationship between the in vitro digestibility of dry matter and the salt-soluble protein index was assessed. It was found that the use of salt-soluble protein index as an indicator of the may lead to doubtful conclusion due to confounding factors (temperature and moisture content). Although this study has achieved some progress in understanding the possible link between corn drying parameters and their effects on the performance of poultry and pigs feeding using corn-based diets, as well as on methodologies that may be used to assess the nutritive value of dried corn grains, complementary studies aiming to determine the effectiveness of these effects on livestock and pigs have to be done. [less ▲]

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See detailCarbon dioxide and vegetable oil for the synthesis of biobased polymer precursors
Alves, Margot ULg

Doctoral thesis (2016)

Although it is a thermodynamically and kinetically stable molecule, carbon dioxide can be converted into five- and six-membered cyclic carbonates by coupling with epoxides or oxetanes, respectively, using ... [more ▼]

Although it is a thermodynamically and kinetically stable molecule, carbon dioxide can be converted into five- and six-membered cyclic carbonates by coupling with epoxides or oxetanes, respectively, using appropriate catalysts. Cyclic carbonates are used as green solvents, electrolytes for Li-ion batteries or intermediates for the synthesis of polymers. However, the catalytic performance must be further enhanced in particular for the coupling of CO2 with epoxidized vegetable oils or oxetanes. In this context, we developed a new highly efficient bicomponent homogeneous organocatalyst composed of an ammonium salt as the catalyst and fluorinated single or double hydrogen bond donors as co-catalysts. First, a screening of onium-based catalysts and hydrogen-bond donors was performed. Performances of the catalysts and optimization of the reaction was realized through detailed kinetics studies using in-situ FTIR/Raman spectroscopy under pressure. We demonstrated that fluorinated alcohols showed unexpected co-catalytic activity due to synergisms between the onium salt and fluorinated co-catalysts enabling the fast and selective addition of CO2 onto model epoxides and epoxidized vegetable oils under solvent-free and mild experimental conditions. The use of this powerful dual catalyst was then extended to the first organocatalytic coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonates that were used as precursor of CO2-based polyurethanes by chain-extension with a diisocyanate. In addition, a fine comprehension of the mechanisms was investigated by DFT calculations highlighting that the co-catalytic performance of the onium salt/fluorinated alcohol binary catalyst arose from the strong stabilization of the intermediates and transitions states by hydrogen-bonding. To date, through comparative studies, we evidenced that this new catalyst is one of the most performing and versatile system enabling the coupling of CO2 both with epoxides or oxetanes. [less ▲]

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See detailLe théorème fondamental comme pierre de touche de l'enseignement et de l'apprentissage de l'analyse au secondaire
Balhan, Kevin ULg

Doctoral thesis (2016)

Using the Anthropological Theory of Didactics and the Theory of Didactic Situations, this thesis brings an answer to several questions of learning the fundamental theorem of the analysis and shows that ... [more ▼]

Using the Anthropological Theory of Didactics and the Theory of Didactic Situations, this thesis brings an answer to several questions of learning the fundamental theorem of the analysis and shows that what prevents to understand it is significant of dysfunctions of the teaching of the analysis at the secondary level in French-speaking Belgium. [less ▲]

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See detailStudying the genetics of Mendelian and complex traits with high-throughput genotyping and sequencing in cattle
Li, Wanbo ULg

Doctoral thesis (2016)

Background For decades, identifying genes and mutations underlying inherited diseases and economically import traits has been at the core of genetic studies in domestic animals. The initial arduous task ... [more ▼]

Background For decades, identifying genes and mutations underlying inherited diseases and economically import traits has been at the core of genetic studies in domestic animals. The initial arduous task of gene mapping with microsatellites or low-density SNP panels was then followed by a often fruitless and tedious attempt to isolate the causative mutations for both monogenic and polygenic traits. The availability of high-density SNP arrays considerably accelerated the gene mapping process. More recently, advances in second-generation high-throughput sequencing (HTS) including whole genome, exome, and RNA sequencing have brought tremendous efficiency into dissecting the genetic underpinnings of phenotypes of interest. In this thesis, we describe the use of these new technologies to decipher the genetic basis of several monogenic and polygenic traits, in both forward and reverse genetic settings. Results We first describe the use of medium-density SNP arrays to dissect genetic basis of a monogenic disease (Crooked Tail Syndrome, CTS), as well as of complex phenotypes related to meiotic recombination in cattle. With regards to CTS, we first demonstrate that a common 2bp-deletion in the MRC2 gene causes the condition in Belgian Blue cattle (BBC), and that the frequency of the condition is due to a pleiotropic effect of the mutation on muscle mass. We discover a second loss-of-function mutation in the same gene MRC2, supporting the hypothesis of pleiotropy and balancing selection. With regards to recombination, we report that genetic variants in REC8 and RNF212 affect the genome-wide recombination rate in cattle. The RNF212 gene has also been shown to be associated with genome-wide recombination rate in humans, however REC8 is not supported as a candidate gene by newer data. We also demonstrated that several variants in the zinc-finger domain of a gonosomal PRDM9 paralogue influence hotspot usage in cattle, reminiscent of previous findings in human and mice. The subsequent application of HTS technology in forward genetic analyses, allowed us to identify: i) an intronic mutation in the PIGH gene that causes the skipping of exon 2, and is the cause of arthrogryposis in BBC, ii) a 3.3 kb deletion removing exons 25-27 of the FANCI gene, that causes brachyspina in Holstein-Friesian cattle. We finally used a reverse genetic approach to identify embryonic lethal (EL) mutations compromising fertility in beef (BBC) and dairy cattle (Holstein-Friesian and Jersey). We mined whole genome and exome sequence data from more than 500 animals for candidate embryonic lethal variants corresponding to loss-of-function (stop gain, frameshift and splice site variants) and disruptive missense variants. By doing so we demonstrate that against expectations domestic Bos taurus cattle are genetically more variable than humans including Africans, however, that their burden of disruptive variants is similar, amounting to ∼100 such variants per individual. We interpret this as resulting from more effective purifying selection in recent times as a result of increased inbreeding. We have genotyped thousands of animals for thousands of EL candidates, and estimate – from the observed depletion in homozygotes - that no more ∼15% of those are developmentally essential. We do not find evidence for synthetic epistasis between candidate EL mutations. By evaluating the departure from Mendelian expectations in matings between carrier sires and dams, we unambiguously demonstrate the embryonic lethal nature of nine relatively common candidate EL variants. All of them affect genes that are involved in basic cellular processes. We demonstrate that only one of these would have been detected using the haplotype-based approach that were applied thus far. The established list of loss-of-function variants is being mined for putative non-lethal, yet major phenotypic effects of medical relevance. Among these, we uncovered a 10-bp deletion in the MLPH gene, which results a premature stop codon, that causes diluted color – ‘cool gray’ – in BBC. Conclusions and Perspectives Due to the intensive use of some elite sires by means of artificial insemination in cattle, several outbursts of genetic defects have been observed in recent years. We herein demonstrate that uncovering the genetic basis of such Mendelian disorders can be very effective when integrating high-throughput genotyping and sequencing technology. Fertility in cattle and other domestic animals has declined over the last decades. Our discovery of a number of embryonic lethal variants segregating in cattle provide a complementary explanation for the decline in fertility, in addition to the theory of negative energy balance of high producing cows. The reverse genetic approach we developed for screening EL variants has at least two advantages. First, our approach also works in small sized populations. Second, our approach has higher sensitivity than the haplotype-based approach. It has been suspected for some time that most of the variants underlying complex traits map to noncoding regions. Deciphering the functional consequence of these regulatory variants has proven challenging. The ENCODE projects in human and mice provide good examples of how high-throughput functional assays based on NGS technology may enhance our knowledge of the non-coding regions of the genome. It is reasonable to anticipate that the release of ENCODE-like data in the animal research field will assist in the discovery of the genetic basis of complex traits at an unprecedented pace. [less ▲]

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See detailEtude des intermattes des herbiers à Posidonia oceanica
Abadie, Arnaud ULg

Doctoral thesis (2016)

Among Mediterranean marine ecosystems, Posidonia oceanica (L.) Delile seagrass meadows form a habitat playing an important ecological and economical role. They form heterogeneous seascapes influenced by ... [more ▼]

Among Mediterranean marine ecosystems, Posidonia oceanica (L.) Delile seagrass meadows form a habitat playing an important ecological and economical role. They form heterogeneous seascapes influenced by the impact of natural and anthropogenic phenomenon (of which the anchoring of leisure ships). These impacts lead to the formation of sand and bare mat patches called ‘intermattes’. By describing and using intermatte characteristics observed in Calvi Bay and more widely around Corsica, these PhD works precisely described intermatte and P. oceanica seascape dynamics in order to develop new methods of analysis. On the one hand, natural sandy intermattes formed by bottom currents show two types of border. Each has its own characteristics at the level of the sediments biogeochemistry. On the other hand, anthropogenic intermattes generated by anchoring (bare mat) present different sizes and shapes resulting from specific dynamics. They are not recolonized when the anchoring pressure remains high. A depletion of the substrate chemical quality occurs after the mechanical destruction. A new cartographic seascape index, the Patchiness Source Index, was created using the size and the nature of intermattes at large spatial scale. After a comparison of methods used for the study of intermattes, two new indices (Map Anchoring Index and Anchoring Index) for managers of coastal areas were developed to evaluate the impact of anchoring within P. oceanica meadows. [less ▲]

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See detailSleep and Electroencephalography, Preprocessing and analyses of a specific sleep EEG pattern
Coppieters't Wallant, Dorothe ULg

Doctoral thesis (2016)

Preprocessing and analyses of a specific sleep EEG pattern. Automatic detection methods, self-adjustable to individuals characteristics, were developed in order to remove artefacts from EEG sleep ... [more ▼]

Preprocessing and analyses of a specific sleep EEG pattern. Automatic detection methods, self-adjustable to individuals characteristics, were developed in order to remove artefacts from EEG sleep recordings, detect sleep spindles and analyse NREM power spectrum. Methods are described, assessed and discussed. [less ▲]

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See detailContribution to the Characterization of Piston Expanders for Their Use in Small-scale Power Production Systems
Oudkerk, Jean-François ULg

Doctoral thesis (2016)

Piston expanders are well suited for small scale power generation (<50kW) using heat engines such as Ericsson engine or Organic Rankine Cycle (ORC) system. Both systems offer the possibility to use ... [more ▼]

Piston expanders are well suited for small scale power generation (<50kW) using heat engines such as Ericsson engine or Organic Rankine Cycle (ORC) system. Both systems offer the possibility to use renewable energy sources and are increasingly considered in light of the economic and environmental context. This thesis aims at contributing to the knowledge and the development of piston expanders by presenting modeling, simulation and experimental investigations. Two types of piston engine models are proposed. The first type (denoted as “detailed”) describes the shaft angle (or time) evolution of the state of the fluid in the control volume limited by the cylinder wall and the piston. The second type of model (denoted as “semi-empirical”) is based on theoretical indicator diagram. A calibration process is proposed and applied with the measurement collected on two different expanders. The detailed model is first used to simulate an Ericsson engine. The simulations allow for the optimization of the pressure ratio, the determination of the ratio between the swept volumes of the expander and the compressor, the computation of the valve timing and the evaluation of the potential performances. The main modifications made to turn an available Internal Combustion Engine (ICE) into an Ericsson engine are described. This prototype is then tested but did not run as expected. The identified reasons are a too high leakage rate, a too large cut-off ratio and a too low expander supply temperature. These three features led to insufficient pressure. Nevertheless, a compressor is used to rise the pressure up to 7 bar in order to test the expander part. This expander shows a maximal isentropic efficiency of 59% at 600 RPM with a pressure ratio of 5. A swash-plate expander integrated into an ORC using R245fa is also investigated in a wide range of operating conditions. Performance maps in terms of pressure ratio and rotational speed are given. Maximal reached isentropic efficiency is 54% at 2500 RPM for a pressure ratio of 10.5. Experimental results obtained on both expanders are analyzed with the same methodology to assess the importance of each source of losses. This methodology is based on the disaggregation of the isentropic efficiency into different factors. Each of these factors represents one source of losses. In-cylinder pressure measurements are performed in order to measure mechanical losses. Leakage effects are simulated with the detailed model. Finally, an Ericsson engine-based m-CHP unit and an ORC-based m-CHP unit using the swash-plate expander are simulated with the validated semi-empirical model. Ericsson engine system shows a 6.5% electrical efficiency while the ORC system shows en efficiency of 8.2%. For both systems, possible improvements are simulated. It is shown, among other things, that the benefit of an increase of the built-in volume is limited by the decrease of the mechanical efficiency. [less ▲]

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See detailProcessus écologiques et évolutifs impliqués dans le succès de l’introduction de Quercus rubra L. en Europe
Merceron, Nastasia ULg

Doctoral thesis (2016)

Le chêne rouge d’Amérique (Quercus rubra L.) est un arbre originaire d’Amérique du Nord et introduit en Europe à partir de la fin du XVIIème siècle pour l’ornementation et le commerce du bois. Le but de ... [more ▼]

Le chêne rouge d’Amérique (Quercus rubra L.) est un arbre originaire d’Amérique du Nord et introduit en Europe à partir de la fin du XVIIème siècle pour l’ornementation et le commerce du bois. Le but de cette thèse est de comprendre les mécanismes écologiques et évolutifs qui contribuent à la dynamique et au succès de l’introduction de Q. rubra en Europe. Nous avons montré que cette espèce naturalisée et plantée dans certains pays européens parvient aisément à se développer de façon naturelle dans les forêts de feuillus et de conifères. La dispersion de ses glands est notamment rendue possible par des animaux fouisseurs-disperseurs, tels que les écureuils et les mulots, qui cependant préfèrent les glands du chêne natif Q. robur. Lors de l’introduction d’une espèce dans un nouvel environnement, des processus évolutifs sont susceptibles de se produire et d’engendrer des modifications phénotypiques et génétiques au sein des populations introduites. Une analyse comparative de la structure et de la diversité génétique des populations natives et introduites de Q. rubra a démontré que seulement deux des trois groupes génétiques de l’aire américaine sont actuellement présents en Europe. Aucun goulot d’étranglement fort n’a été détecté lors de l’introduction des populations en Europe laissant supposer que des introductions multiples ont pu maintenir la diversité génétique dans les populations introduites. Une analyse comparative des traits phénotypiques a permis de montrer que les populations introduites de Q. rubra présentent une croissance supérieure par rapport aux populations natives. Une différenciation génétique au sein des populations introduites est en cours pour le trait de débourrement foliaire suggérant une possible évolution adaptative rapide depuis l’introduction. [less ▲]

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See detailAssessment of fodder biomass in Senegalese rangelands using earth observation and field data
Diouf, Abdoul Aziz ULg

Doctoral thesis (2016)

Senegalese livestock size has largely increased during the last three decades in relation to the population growth. The fodder biomass stock available at the end of the growing season, therefore, becomes ... [more ▼]

Senegalese livestock size has largely increased during the last three decades in relation to the population growth. The fodder biomass stock available at the end of the growing season, therefore, becomes increasingly limited to meet feeding needs of pastoral livestock which provides third of the national agricultural wealth. With the reduction of natural grazing lands mostly generated by the expansion of croplands, and the reduction of fodder biomass production due to drought effects, the increase of the livestock size leads to the rangelands overload whose persistence can lead in turn to their degradation. A technique based on a simple linear relationship between the temporal integration of the Normalized Difference Vegetation Index (NDVI) and the ground biomass data, developed in the 1980s, has been operationally applied by the Centre de Suivi Ecologique (CSE) of Dakar (Senegal) to assess the fodder biomass available in rangelands at the end of the growing season. The derived map of total biomass production enables to help pastoral livestock managers as well as national stakeholders against food insecurity and natural resources degradation. Carried out annually, this approach comprises unfortunately some uncertainties as: (1) the saturation drawback of NDVI in areas with high biomass productivity, (2) the temporal scale which is restricted to biomass data of the ongoing year not being used again in the following year, (3) the low predictive ability due to the large time gap between data collection and published results, and (4) the high costs for annual data collection. In addition, although the earth observation (EO) data have largely progressed during the last three decades, this technique has not changed over this period and consequently is not state-of-the-art. To tackle these limitations and advance the traditional method, new statistical models that include new earth observations datasets and historical in situ plant biomass data were developed for estimating and / or predicting the forage availability at the end of the growing season in Senegalese semi-arid rangelands. A backward analysis of the linear regression approach currently applied in Senegal provided evidence that nonlinear regression functions such as Exponential and Power are more suited to estimate the end-of-season total biomass in this region using annual data solely. A completely new methodology using multiple-linear models which include various phenological metrics from the time series of the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) and 14 years of in situ total biomass samples was developed. The proposed approach provided more reliable and accurate estimates as compared to the current CSE biomass product. Multiple-linear models developed with specific metrics adapted to ecosystem properties increased the overall accuracy of the fodder biomass estimates and mitigated the saturation of FAPAR obtained with models run across the whole study area. With this new approach, timely information about possible deficits/surplus of total fodder biomass can be provided to stakeholders using phenological metrics that are available relatively early in the growing season. Another new approach based on a machine learning algorithm (i.e., Cubist) was developed, as never done before, to assess herbaceous biomass in Senegalese Sahel. Three Cubist models using FAPAR seasonal metrics and/or agrometeorological variables (i.e., soil water status indicators) were established and compared. The Cubist model including both FAPAR and agrometeorological variables provided the best estimation performance. This model enabled to mitigate the saturation affecting optical remotely sensed vegetation data in areas of high plant productivity as well as the discrepancy between herbaceous biomass and greenness, and corrected therefore for herbaceous biomass underestimations observed with the sole FAPAR based model, particularly in sparsely vegetated areas. In contrast to the date of the growing season onset retrieved from FAPAR seasonal dynamics, the rainy season onset was significantly related to the herbaceous biomass and its inclusion in models could constitute a significant improvement in forecasting risks of fodder biomass deficit. The methods developed in this research provide tools to assess Senegalese forage resources at two levels: herbaceous and total fodder biomass (Herbaceous + woody leaf biomass). They require limited data and free available software and therefore can be easily replicated in other countries of the West African Sahel. [less ▲]

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See detailDECONSTRUCTING LANDSCAPE IN THE MIND OF PEOPLE: AN EXPLORATION OF EVERYDAY AND WIND ENERGY LANDSCAPES
Vanderheyden, Vincent ULg

Doctoral thesis (2016)

In the 19th century, geography was defining itself as the science of landscape, led by German and French schools. Other disciplines were also interested in landscape, each one with its own definition(s ... [more ▼]

In the 19th century, geography was defining itself as the science of landscape, led by German and French schools. Other disciplines were also interested in landscape, each one with its own definition(s). In public policy, landscape has remained, for a long time, a heritage object to be protected (e.g. cultural landscapes of UNESCO). In 2000, the European Landscape Convention, which aims to safeguard the European landscape diversity, proposed a common definition. This includes the idea of areas perceived by people. One of the recommendations of the Convention is the call to focus on other landscapes that only heritage landscapes, such as everyday landscapes and degraded landscapes. The convention also calls for better management and planning practices towards landscape changes. Today, landscape is often invoked as arbitrator in territorial disputes. This is the case in discussions for the installation of wind farms. Newcomers and farmers ‘visions on landscape are often opposed: idyllic landscape for living and recreation for the firsts, working environment for the seconds. Despite the European Landscape Convention, many grey areas remain about how to achieve its goals. Long before it, leading researchers called for a better interest in everyday landscapes. Yet they remain the poor relation in landscape research, to the benefit of natural, wild landscapes. Many uncertainties also remain on how non-specialists perceive their ordinary landscapes and how they have appropriated the landscape concept. The research helps to fill this double gap, deconstructing the concept through the lens of ordinary landscape. With several research questions, I plan to explore what is the landscape in people’s mind, how they conceptualize it, how they think it and how they question their own views on landscape. I will show how these conceptualizations and thoughts are shaped by the living environment, which often provides the tools necessary to the apprehension of the landscape. I will analyse how new elements such as wind farm can disrupt these patterns. The first part of the research is dedicated to the overall perception of their ordinary landscapes by Belgians, especially facing the issue of wind energy. Using a photo-questionnaire survey, we surveyed a representative sample of the Belgian population (n = 1542). Based on this investigation a model was developed. It highlights the positive influence of forest cover and the lack of anthropogenic elements, but also the negative influence of its urbanization and too flat relief on landscape attractiveness. The influence of wind turbines has to be qualified according to the landscape in which they are implanted. In landscapes strongly marked by the human footprint, they seem perceived as increasing the landscape attractiveness. In unspoilt landscapes, they seem rather to contribute to their degradation. These global findings are nuanced in further research. Deeper analysis shows that Flemish people have a more positive view of the landscape than Walloons. I hypothesize a decisive influence of the local context. Indeed, Flemish landscapes are generally more urbanized and marked by man than most of the Walloon landscapes. The building of wind farms seems to change or even reverse the situation. The analysis also shows significant influences related to educational level and gender. Anthropogenic landscapes are less disregarded by low educated people. Women seem to attach importance to stewardship and landscape maintenance. In contrast, although suspected, age influence has not been formally demonstrated. The second part of this dissertation, the cornerstone of this doctoral research, aims at deconstructing the landscape concept in the mind of people. In this part, wind farms are no longer considered as a case study, but as a leitmotif. I deeper surveyed smaller groups (n = 54) in three areas of Wallonia (Walloon Picardy, between the Sambre and Meuse rivers, and Ardennes) with qualitative techniques. This survey was conducted five years after the first. The analysis of the vocabulary used by the regional sub-groups shows that people are not equipped the same way for analysing landscapes. The experience of living environment seems to be crucial in providing analytical keys. Thus Ardennes people seem better equipped to talk about the forest, marking their landscapes, while the Picards seem more loquacious about their iconic cultivated landscapes. The research also highlighted different landscape analysis patterns. Some people ordered landscapes according to their degree of naturalness, the less spoiled landscapes being the most attractive. On the contrary, fewer attach importance to landscapes where human footprint is clearly visible. Some respondents remain in a purely aesthetic landscape analysis, while others project themselves into the landscape, imagining they are performing different actions. Depending on their interests, these actions influence the perception of one same landscape. Research shows that this overall pattern analysis is disturbed by various factors. The recognition of certain places transformed landscape analysis in an analysis of the place, with the emotional changes that this entails. The position of the participants facing wind energy projects also appears sharper. In the time between the two parts of the research, Wallonia has experienced unprecedented wind development; opinions have therefore had time to form. This was not yet totally the case during the first survey. Beyond these major disruptions, the research also shows clear influences of the ordered character of landscapes, their living character and variety of land uses. The research also highlights the influence of non-visual criteria such as noise or odours detectable in the landscape. In conclusion, the research shows that respondents often show a sense of landscape, weaker than sense of place and stronger than aesthetic. [less ▲]

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See detailThe dynamics of market, credit and liquidity risk in the US corporate bond market
Heck, Stéphanie ULg

Doctoral thesis (2016)

Market, credit and liquidity constitute important risk factors in financial markets. Investors looking for optimal combinations of risk and return have to monitor their portfolios with regard to each of ... [more ▼]

Market, credit and liquidity constitute important risk factors in financial markets. Investors looking for optimal combinations of risk and return have to monitor their portfolios with regard to each of those factors. This work brings answers to some of the challenges presented by these three risk factors in the US corporate bond market. Market risk is the earliest and most widely acknowledged risk factor, affecting all financial securities. The risk that the issuer of the bond might go bankrupt introduces credit risk for corporate bonds. Finally, these securities are also characterized by a low trading frequency. Liquidity in this market has been severely affected by the recent global financial crisis as well as by the regulatory changes that followed the crisis. The first part of this dissertation studies the return premium investors require in compensation for undertaking credit risk. It is shown that distributional characteristics of individual assets and in particular the contribution of an asset’s return to the market portfolio’s skewness and kurtosis are important determinants of these premiums. The second part explores commonality in individual bond liquidity levels. It is shown that the pricing of liquidity in yield spreads is essentially due to this commonality. The final part of this dissertation designs a corporate bond market index based on the repeat-sales technique. The index adequately captures aggregate market dynamics and contributes to the explanation of the cross-section of individual corporate bond returns. [less ▲]

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See detailPlace de l'élevage bovin dans l'économie rurale des Peuls du Nord Bénin
Chabi Toko, Roukayath ULg

Doctoral thesis (2016)

Fulani belong to a socio-cultural group mainly encountered in West Africa and usually raises cattle. In Benin, Fulani are predominantly met in the two eastern departments of the North where they lead an ... [more ▼]

Fulani belong to a socio-cultural group mainly encountered in West Africa and usually raises cattle. In Benin, Fulani are predominantly met in the two eastern departments of the North where they lead an agro-pastoral way of life. In addition to livestock farming, they cultivate food and cash crops such as cotton. However, they hold majority of the country’s cattle population. The present study was initiated to understand to what extend cattle contributes to their rural economy. A stratified random sample of 150 heads of Fulani households, cattle farmers have been identified in Malanville, Banikoara and Kalalé districts in Borgou and Alibori departments. The criteria considered were: the agro-ecological zone, cattle population and the importance of Fulani population. The first series of surveys enable to characterize Fulani’s cattle farming system and their family farms. Among the 50 heads of households of Kalalé district (which has the more important Fulani community), 16 were selected and it is within their households that the study continued. The households selected were that with a better milk production. Surveys were then carried out during two years, both in dry season and rainy season to describe the Fulani’s household’s economy. The cattle stock composition showed a gender imbalance, with a preponderance of female stock (76%). Cattle herds which average size were 66 animals are made of 86% of Borgou breed. The herds have low breeding performance characterized by a high rate of calf mortality (10%) and low reproductive parameters: calving and fertility rates were 64%. The purchase of fodder in dry season, which concerns 17% of farmers, is a practice encountered in agroecological zones that register light rainfall. Fulani’s large households enable them to have enough family labor to carry out both livestock and agriculture activities. The land is mostly inherited and the average size for a household is about 10.5 ha. All Fulani households are crops producers of which majority (80%) is consumed. A significant part (45%) of them grow an average of 3.3 ha of cotton. In Fulani family farms, cattle represent 52% of the household livestock size; there is also small ruminants and poultry. This cattle permit to majority (76%) of Fulani households to have milk for sale. But milk is managed to favor household consumption and ensure the herd's reproduction. The organization around milk involves male and female. The profits from milk and cheese are distributed among the women of the household at various levels. Although the low (7%) cattle market rate, it contributes significantly (68%) to the household’s monetary income in rainy season and represents the second source (27%) of revenue in dry season. The 20% of food products are mainly sold in dry season and thus contribute to the majority (64%) of income sources. However, when rains started late and the delayed payment of cotton fees, the majority of Fulani households’ cash income in the rainy season, came from cotton (64%) and food products (23%). The growing involvement of Fulani cattle herders of northern Benin on the foodstuffs market and in cotton will lead to two types of farms with opposed production targets (those that will favor livestock and others agriculture). Fulani are a target population that should receive a little more support from authorities because enable them to value their resources would ensure availability and accessibility of food and pastoral products and contribute to the improvement of country’s agricultural production. [less ▲]

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See detailInventory routing for perishable products
Rezaei Sadrabadi, Mahmood ULg

Doctoral thesis (2016)

We explore three problems in this thesis and develop solution methods for each problem. First, an inventory routing problem for a perishable product with stochastic demands is considered and different ... [more ▼]

We explore three problems in this thesis and develop solution methods for each problem. First, an inventory routing problem for a perishable product with stochastic demands is considered and different approximate solution methods are developed to solve. Based on computational experiments, the solution methods are compared in terms of average profit, service level, and actual freshness. The impact of relevant parameters on the performance of the solution methods is investigated. Managerial insights are drawn by analyzing the impact of shelf life and store capacity on the profit. The value of considering uncertainty and the value of accessing full information are measured. The computational results highlight that a simple ordering policy can often replace a more sophisticated solution method, while preserving the same efficacy. Second, we introduce a vehicle routing problem (VRP) where a set of stores places deterministic orders to a logistics service provider (LSP) for two successive periods. Deliveries requested in each period can be shifted by the LSP to the other period, possibly with modified quantities. The LSP incurs a penalty for any diversion from the initial delivery period. The data regarding shifted delivery quantities and penalties are provided by the stores. From the perspective of the LSP, diversions could be beneficial if savings in the routing costs outweigh the penalties. In this work, we introduce a new two-period VRP model where the LSP seeks to improve its total cost, compared to solving two independent VRPs with fixed delivery periods, by allowing deliveries to be shifted. We solve this model to optimality by an efficient branch-and-price algorithm implementing several cutting-edge techniques. We draw algorithmic and managerial insights based on our test instances. Third, a two-period VRP is considered where the orders placed by stores for each period can be partially shifted to the other period, given that the sum of the delivery quantities in two periods to each customer is fixed. A linear penalization of delivery shifts is assumed based on the quantity shifted. We represent two mixed integer linear programming (MILP) formulations for the problem. A column-row generation algorithm to solve the LP-relaxation of the first formulation is developed. To solve the LP-relaxation of the second formulation, we develop a column generation algorithm. Details of two label-setting algorithms to solve the pricing problems of the column-row generation and column generation algorithms are discussed. Numerical results can be compared with a similar model in which only full delivery shifts are allowed. [less ▲]

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See detailEvaluation de l'impact socio-économique en aval des aménagements hydroélectriques : exemple du barrage hydroélectrique de Nam Mang 3 au Laos
Kouangpalath, Phimthong ULg

Doctoral thesis (2016)

Since two decades, hydropower projects are multiplying in Laos. These projects are often criticized in the media and civil society organizations for their negative social and environmental impacts, which ... [more ▼]

Since two decades, hydropower projects are multiplying in Laos. These projects are often criticized in the media and civil society organizations for their negative social and environmental impacts, which can also generate regional geopolitical tensions in Southeast Asia. In this sensitive context, our interest has focused on rural populations downstream of hydropower dams; these populations are often ignored by compensation programs reserved for displaced populations from upstream. The objective of the research is to identify and assess the socio-economic effects in the Nam Nyam Valley (Vientiane Province, Lao PDR), downstream of the Nam Mang 3 hydropower dam. A current diagnostic-analysis of the agrarian system of the valley, together with a characterization of the recent evolution was conducted by household surveys in different villages. The diachronic study of agrarian dynamics and understanding the links of causality enabled us to model a counterfactual scenario to isolate, by difference with the current situation (scenario "with project"), the specific effects of the dam. In parallel, a similar approach was employed downstream of the Nam Lik 1-2 hydropower dam in the Meuang Feuang basin (Vientiane province, Lao PDR) in order to compare with the results of the Nam Nyam Valley, to better characterize the specific effects of hydropower infrastructure developments. As a result, the evolution of agrarian systems in the valleys downstream depends on the combination, variable over time, of several political, economic, demographic, environmental, technical, social, etc. factors. A hydropower dam, like the one of Nam Mang 3 is part of complex and continuous dynamics of transformation; its impact is not only the sole cause of changes affecting the communities. The socio-economic effects influence over time a much larger population downstream than upstream, even if the media attract the attention on punctual displacement of villages (and their compensation) to fill the reservoir. The hydropower dam project effects differ according to phases (construction, reservoir filling, operation) and social categories, depending on the investment capacities, adaptation and networks of each category. The socio-economic impact downstream is not assumed to be correlated with the size of hydropower dam, but its design and mode of water management are the key criteria of the importance of negative externalities. The massive investments in these projects have also positive effects for the local population, such as the development of local infrastructure, which open up villages and provide access to public services and markets. However, these positive externalities mainly concern well-off villagers disposing of capital and networks to benefit of new opportunities, while poor families are more vulnerable to changes in the political, environmental, technical and socio-economic context. Thus, hydropower dams contribute to increased socio-economic differentiation in villages downstream, with the poor left out of the profits from the energy export. [less ▲]

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See detailBelgian Heterosexuals’ Attitudes towards Gay and Lesbian Couples and Same-sex Parenting
Scali, Thérèse ULg

Doctoral thesis (2016)

The legal situation of Belgian gay men and lesbians may be perceived as one of the best in Europe. Indeed, the Belgian Parliament has legalized marriage and parenting for same-sex couples, has enacted ... [more ▼]

The legal situation of Belgian gay men and lesbians may be perceived as one of the best in Europe. Indeed, the Belgian Parliament has legalized marriage and parenting for same-sex couples, has enacted anti-discrimination laws, and has designed and funded several action plans to combat homophobia. Since the opening up of marriage to same-sex couples in 2003, around a thousand gay and a thousand lesbian marriages are celebrated each year in Belgium (Direction Générale Statistique et Information Économique, 2015). Moreover, since the legalization of parenthood for gay men and lesbians, more and more same-sex couples adopt children or resort to artificial insemination, and the total number of children growing up with same-sex parents is growing steadily. Thus, a new reality is emerging: the reality of same-sex headed families. However, in spite of the civil rights granted to gay men and lesbians, the issue of social acceptance of same-sex couples and their children still remains and Belgium continues to record increasing levels of violence against homosexual people. Therefore, the main objective of the present thesis was to explore Belgian heterosexuals’ attitudes towards same-sex marriage and same-sex parenting. The first goal was to investigate the social and personal factors that may be associated with positive and negative attitudes towards same-sex marriage and those towards same-sex parenting (Study 1). The results of self-report questionnaires (N = 1168) revealed that the general attitude towards gay men and lesbians, gender-role traditionalism, beliefs in the origin of homosexuality, representations about child well-being and contact are major predictors of attitudes towards gay and lesbian civil rights. Moreover, results revealed that attitudes differed according to participant’s gender (heterosexual men are less supportive of both same-sex marriage and same-sex parenting than heterosexual women). The respective role of several variables was also discussed (gender-role traditionalism, beliefs in the origin of homosexuality, general attitudes towards gay men and lesbians, representations of child well-being and contact). We demonstrated that increasing intergroup contact can help diminish the impact of some personal beliefs on attitudes towards same-sex parenting. Moreover, results revealed that the degree of support differed in regard to the different types of parenthood. Moreover, several authors in the field of social psychology highlighted the role of beliefs and social representations upon attitudes (Dardenne, 2006). Specifically, attitudes towards gay men and lesbians as parents seem to be somehow beliefs-based (Costa, 2013). Our next objectives were to explore the arguments in favour and against same-sex parenting, both in the general population through the comments posted on social networks (Study 2) and with health-care professionals working in family counselling centres (Study 3). Both studies highlighted positive and negative arguments, each linked to one of the following category: societal and legal context, religiosity, contact, representations of homosexuality, gender-role traditionalism, general attitudes towards gay men and lesbians and representations about child well-being. Moreover, a comparative analysis of the two samples allowed us to state that the arguments held by the social workers are quite similar to those held by the citizens in the general population. Thus, we concluded that health-care professionals’ attitudes are based on naïve knowledge rather than on scientific knowledge, and this lack of scientific knowledge on same-sex parenting has an impact not only on social workers’ attitudes but also on their interventions. To conclude, our work demonstrated that, in Belgium, the barriers to accepting rainbow couples and families are no longer legal, but social. Nearly ten years after the law on adoption for same-sex couples, the country remains relatively conservative and traditional in some regards. Therefore, by demystifying and deconstructing ill-conceived ideas, it will be possible to move towards greater acceptance. Thus, more positive attitudes may be reached when in-depth work has taken place on social perceptions, particularly around questions of gender-role traditionalism, the representations of homosexuality and same-sex lifestyle, and around the child’s well-being. In particular, it is important to deconstruct stereotypes about gay men and lesbians and open minds to other possible forms of families. To achieve those goals, the role of intergroup contact is very important. It is, consequently, also down to psycho-social trainers to create homophobia prevention programmes based on tailor-made training sessions, taking into account the specificities of each group and their beliefs. Finally, we recommend that future research focuses upon same-sex parent families, in order to enrich the scientific data available on these families and their experiences. [less ▲]

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See detailQuand le plan zonal de sécurité rencontre la police locale Analyse sociologique du processus de traduction d'un artefact d'action publique
Croquet, Alice ULg

Doctoral thesis (2016)

The thesis examines the implementation of a security policy introduced by the 1998 Belgian police reform through the public policy instrument that declines the latter on local level, that is the area ... [more ▼]

The thesis examines the implementation of a security policy introduced by the 1998 Belgian police reform through the public policy instrument that declines the latter on local level, that is the area security plan. The thesis is based on four case studies and crossed inputs from the Actor-Network Theory and the Sociology of organized action. It traced the career of the area security plan in the local police organizations as the construction of a “sociotechnical system”. We analyze the work of mutual translation that occurs between the instrument and the police environment around four “events” making them progressively irreversible. On the one hand, we discover the “turbulent” nature of the regulatory control within police organizations. On the other hand, we settle the performative nature of the area security plan, of which we consider the introduction in the police landscape as an artifact at the service of the structural compromise that has been stabilized since the reform. [less ▲]

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See detailXérogels de carbone comme matériaux modèles pour l'étude du comportement électrochimique en tant qu'anodes de batteries Li-ion
Piedboeuf, Marie-Laure ULg

Doctoral thesis (2016)

The main goal of this thesis aims at shedding some light on how the textural and surface chemistry properties of porous carbons influence their electrochemical behavior when used as anodes for Li-ion ... [more ▼]

The main goal of this thesis aims at shedding some light on how the textural and surface chemistry properties of porous carbons influence their electrochemical behavior when used as anodes for Li-ion batteries. In this respect, carbon xerogels (XC) have been used as model materials, since their tunable pore texture and surface chemistry have made it possible to perform a systematic study, where each variable could be modified independently. The first target consisted in obtaining a series of carbon xerogels with controlled meso- or macropore textures. These materials are made of interconnected nearly spherical microporous nodules, delimiting meso- or macroporous voids. Several series of carbon xerogels with controlled pore textures have been prepared. As a result, materials with a wide range of meso- or macropore sizes have been obtained and the influence of the aqueous formaldehyde precursor solution on the final textural characteristics could be highlighted. Additional post-synthesis treatments have been performed in order to tune the microporosity as well as the surface chemistry of selected materials. The second aim was to control and set several variables other than the pore texture and the surface chemistry of XC, that could influence their behavior as active materials for Li-ion batteries, such as the particle sizes or the electrode characteristics. In this respect, an in-depth study of the ball-milling process of carbon xerogels has allowed to determine the conditions leading to materials with a well-defined particle size distribution centered on 10 µm. The specific surface area, as well as the meso- or macroporosity remain identical from the monolithic form to the final powder. This work has also shown the possibility of using mercury intrusion porosimetry as a tool to assess the mean particle sizes of a XC powder. Several methods for the coating of active materials on current collectors (bar-coating and spray) have been investigated for different ink formulations (organic- or water-based). This study has shown that XC-binder composites resulting from aqueous-based inks preserve the porosity of the starting materials, whereas the microporosity is strongly reduced in the case of the organic pathway. As a result, the method of spraying a water-based ink, with xanthan gum as a binder, seems to be the most appropriate in terms of precision, ease of processing and safety in this case. The third goal consisted in performing detailed electrochemical characterizations of the electrodes produced with carbon xerogels displaying various defined pore textures and surface chemistries. In the case of electrodes obtained upon using an organic ink, a linear relationship is observed between the relative irreversible losses and i) the external surface area of the nodules as well as ii) the specific surface area of the XC-binder composites. In the case of the aqueous electrode processing method and upon using carbon xerogels with tuned microporosity, a linear relationship could be established between the total specific surface area of the starting materials (including micropores) and the irreversible as well as reversible capacities at the first charge-discharge cycle, if the maximum potential is set at 3 V vs. Li+/Li. Finally, after modulation, the surface chemistry has shown to have a significant effect on the accessibility of the surface by the electrolyte as well as on the SEI formation at the first charge-discharge cycle. [less ▲]

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See detailCaractérisation multi-échelle des bandes riveraines des cours d’eau wallons par télédétection active et passive
Michez, Adrien ULg

Doctoral thesis (2016)

Les bandes riveraines des cours d’eau constituent des milieux d’une richesse exceptionnelle aux multiples facettes, comportant les habitats parmi les plus variés, dynamiques et complexes de la surface ... [more ▼]

Les bandes riveraines des cours d’eau constituent des milieux d’une richesse exceptionnelle aux multiples facettes, comportant les habitats parmi les plus variés, dynamiques et complexes de la surface terrestre. Elles sont au cœur des stratégies des politiques de préservation et de restauration de l’environnement qui impliquent la mise en place de suivis multi-échelles devant être répétés dans le temps. La télédétection peut fournir des informations fines tant sur la végétation qui compose les bandes riveraines que sur la structure et les paramètres physiques de celles-ci. Le présent projet de doctorat est articulé autour de l’évaluation de la télédétection en tant qu’outil pour la gestion des cours d’eau ; tant au niveau local (<20 km de cours d’eau, usage de drone) qu’au niveau de l’ensemble du réseau hydrographique wallon (> 12 000 km de cours d’eau). Au niveau local, les drones civils tendent à émerger comme outils de caractérisation environnementale depuis le début des années 2000. Leurs principales caractéristiques sont relatives à leur résolution spatiale et temporelle, permettant d’obtenir des données très fines (résolution au sol ≤ 10cm) au sein d’une fenêtre temporelle très restreinte. Leur usage a été évalué avec succès afin de localiser les plantes invasives des bandes riveraines et de caractériser la composition spécifique et l’état sanitaire de l’aulne glutineux (Alnus glutinosa) en Ardenne. Des résultats satisfaisants ont été atteints dans le cas de l’étude de la détection des trois principales espèces végétales invasives des bandes riveraines wallonnes : balsamine de l'Himalaya (I. glandulifera), berce du Caucase (H. mantegazzianum) et renouée du Japon (F. sachalinensis et F. japonica et hybrides). Les meilleures précisions globales obtenues sont de 97% pour la berce du Caucase. A l’échelle régionale, l’approche développée est basée sur l’usage de données 3D (LiDAR et photogrammétriques) afin de caractériser les bandes riveraines associées à l’ensemble du réseau hydrographique wallon (> 12 000 km) à partir de 6 paramètres. Ces paramètres sont descriptifs de composantes physiques de l’hydromorphologie mais également de la structure des forêts riveraines. Une évaluation des patrons spatiaux de ces paramètres en lien avec différentes informations (occupation du sol, régions naturelles) a été réalisée. S’appuyant sur différentes techniques d’agrégation permettant des visualisations à l’échelle régionale, les résultats obtenus reflètent la connaissance a priori des cordons rivulaires, notamment le constat négatif relatif à la fonctionnalité des bandes riveraines en région limoneuse. Les principales perspectives d’application au domaine de la gestion des cours d’eau sont relatives au développement d’outils d’aide à la décision pour les gestionnaires. A l’échelle locale, une adaptation des solutions développées pour l’usage des drones est nécessaire tant en matière de plateforme (couverture d’un linéaire plus important) qu’en tant qu’outil d’analyse (simplification des chaînes de traitement). A l’échelle régionale, la construction d’indicateurs de gestion nécessitera un travail spécifique quant à la comparaison de la valeur observée à une valeur référence. [less ▲]

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See detailInfluences of electric charges on an isolated drop
Brandenbourger, Martin ULg

Doctoral thesis (2016)

Research such as the famous Millikan experiment or the studies concerning thunderclouds have shown that droplets can be considerably influenced by an excess of electric charges. Indeed, an excess of ... [more ▼]

Research such as the famous Millikan experiment or the studies concerning thunderclouds have shown that droplets can be considerably influenced by an excess of electric charges. Indeed, an excess of charges can affect the intrinsic properties of a droplet, such as its natural oscillation frequency or its internal pressure. Moreover, the electric charges in excess in droplets can also interact with external electric fields. In this thesis, we investigated the influence of electric charges on millimetric droplets that are electrically isolated. In literature, research on isolated charged droplets are mainly focused on droplets with a micrometric size. The lack of studies concerning millimetric charged droplets is explained by the difficulty storing them while avoiding charge leakage. In order to answer to this issue, we examined three storage systems limiting the charge leakage: the microgravity, the vibrating bath method and the Leidenfrost effect. Through these systems, we studied the influence of electric charges on the droplet physical properties, but also the interaction between the charged droplet and its storage system. Furthermore, we investigated the interaction of charged droplets with external electric fields. More precisely, we studied the interaction between two electrically charged droplets and the interaction between one charged droplet and an external homogeneous electric field. A first set of experiments on electrically charged droplets allowed us modeling the charge migration process in liquids and the charge leakage from a millimetric droplet. In particular, we identified and modeled a new mechanism of charges leakage occurring at a time scale of several minutes. Moreover, we confirmed the influence of the electric charges on the droplet surface energy previously deduced from experiments on micrometric droplets. Concerning the three storage systems, the experiments performed in microgravity allowed us describing the influence of the electric interaction on the impact between two charged droplets. The diverse behaviors observed were compared to the cases of impacts between two neutral drops. On a different note, the study of a charged droplet moving on the surface of a vibrating bath because of the influence of an external electric field gave new insights on the interaction between a bouncing droplet and a viscous liquid bath. For example, we observed a ``go-stop" motion during which the droplet horizontally moves when it bounces away and is stopped during its interaction with the liquid bath. We showed that this motion occurs when large droplets are influenced by a weak electric field. Droplets with this kind of motion move with a constant average speed, which makes them easily manoeuvrable. Therefore, the control of the droplet motion led to the development of a new microfluidic prototype. Via this new setup, basic microfluidic tasks can be performed without polluting droplet via contacts with solids or liquids. With these results in mind, we also examined the interaction between two charged droplets bouncing on the vibrating bath. This study brought new insights on the interaction between two charged droplets. Indeed, we observed that two drops with the same charges tend to remain at an equilibrium distance. Our study showed that this equilibrium distance is due to the compensation of the electric repulsion by capillary attraction at the surface of the vibrating bath. Finally, our study of charged droplet in Leidenfrost state on a liquid bath led to a better understanding of the interaction between charged liquid interfaces. Indeed, we showed that electric charges cause the early coalescence of charged droplet because of an increase in the vapor layer drainage. We conclude from our results that an excess of electric charges influences ostensibly the intrinsic behavior of a droplet and its interaction with the environment. Furthermore, each storage system studied brought answers to specific issues. The study of the impact between charged droplets in microgravity outlines new explanations on the behavior of thunderclouds. The results accumulated on the micromanipulation of charged droplet bouncing on a vibrating bath opens the way to a new kind of microfluidic system. Finally, the study on the charged Leidenfrost droplets describes new ways to investigate the influence of electric charges on liquid interfaces. [less ▲]

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See detailLes enregistrements infirmiers : un outil d'efficience. Du RIM aux DI-RHM dans les hôpitaux belges.
Thonon, Olivier ULg

Doctoral thesis (2016)

Le Résumé Infirmier Minimum existe depuis 1988 et un certain nombre des objectifs initiaux ont été atteints. A la fin des années 90, la question de l’actualisation du RIM s’est posée avec acuité étant ... [more ▼]

Le Résumé Infirmier Minimum existe depuis 1988 et un certain nombre des objectifs initiaux ont été atteints. A la fin des années 90, la question de l’actualisation du RIM s’est posée avec acuité étant donné l’évolution des soins de santé en général et de l’art infirmier en particulier. Dorénavant intégré dans une base de données unique, le Résumé Hospitalier Minimal, ce Résumé Infirmier Minimum actualisé, implanté officiellement depuis janvier 2008, a sans aucun doute métamorphosé l’environnement des soins infirmiers. Le chapitre 1 décrit ce processus d’actualisation du RIM. Le cadre conceptuel du RIM « actualisé » définit un tremplin international, en référence à la Nursing Interventions Classification (NIC) utilisée pour sa conception. La visualisation de la variabilité des soins infirmiers se fera dorénavant à travers un langage plus riche et plus précis en passant de 23 à 78 items. La première composante de l’efficience, est abordée dans le chapitre III. Il concerne l’évaluation du niveau de preuve des interventions répertoriées dans les DI-RHM. L’approche justificative de l’outil est abordée dans le chapitre IV de ce travail. Le chapitre V examine dans quelle mesure il serait possible d’allouer les moyens infirmiers de façon plus rigoureuse aux hôpitaux. Le chapitre VI se consacre à l’élaboration de profils de soins infirmiers sur base des DI-RHM et à la mise en évidence de leur potentiel d’utilisation. Nous concluons par une discussion générale reprenant les divers éléments abordés dans ces différentes approches à la lumière du contexte actuel de l’outil. [less ▲]

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See detailEtude des déterminants de l'efficacité organisationnelle des associations sans but lucratif bénéficiaires de microcrédits au Burundi: une approche d'alignement stratégique
Nduwayo, Marie Goreth ULg

Doctoral thesis (2016)

Even if the Henderson and Venkatraman (1993) works on the strategic alignment have paved the way for several research to determine the impact of strategic alignment on companies’ organizational ... [more ▼]

Even if the Henderson and Venkatraman (1993) works on the strategic alignment have paved the way for several research to determine the impact of strategic alignment on companies’ organizational performance, there is absence of consensus in the literature regarding how companies can align. In addition, while the question of the effectiveness of non-profit organizations remains an important topic for researchers, empirical studies of their organizational effectiveness remain rare. We address this issue by taking on account a specific attribute of a difficult economic environment: the threat of survival of Burundian's Non-Profit Associations (ASBL) beneficiaries of microcredits. Thus, our study shows that the strategic alignment of these ASBL is realize through on their adjustment (taken in the sense of finality or condition that is different from the process) to the constraints of their donors. This approach articulate on three registers: in positioning us in the field of research of company strategies, we base on strategic alignment in the context of survival, and then we address survival issues. We demonstrate that the strategic adjustment is the basis of the survival strategies of these microstructures in a Burundian context dominated by insecurity and extreme poverty. The primary needs of these entities are indeed at the root of the adjustment response to key resources provided by microfinance institutions. Thus, the objective of our study is to explain how the strategic alignment of these ASBL to the constraints of the donors can have a decisive influence on their organizational effectiveness (a facet of performance). To this end, we build a model and we test it empirically with 150 ASBL beneficiaries of microcredits created from 1992 to 2011. We prove that their internal organization is an important determinant of their organizational effectiveness and is the basis of their efficiency. This organizational asset has certain particular features and is the result of strategic alignment. [less ▲]

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See detailIsolement et caractérisation de mutants affectés dans le transport d'électrons photosynthétique en anoxie chez la microalgue verte Chlamydomonas reinhardtii. Photoproduction d'hydrogène et Voie de biosynthèse de la phylloquinone.
Emonds-Alt, Barbara ULg

Doctoral thesis (2016)

La microalgue verte Chlamydomonas reinhardtii, qui a contribué de façon remarquable à la compréhension de nombreux mécanismes biologiques tels que la photosynthèse, intéresse aujourd’hui plus ... [more ▼]

La microalgue verte Chlamydomonas reinhardtii, qui a contribué de façon remarquable à la compréhension de nombreux mécanismes biologiques tels que la photosynthèse, intéresse aujourd’hui plus particulièrement le secteur des énergies renouvelables pour sa capacité à produire de l’hydrogène moléculaire (H2) à la lumière. Cette photoproduction d’H2 est liée à la présence en anoxie d’hydrogénases qui sont connectées via la ferrédoxine à la chaîne de transport d’électrons photosynthétique. On distingue deux voies de transfert d’électrons: la première dépendant de la photolyse de l’eau par le PSII (voie PSII-dépendante), la seconde de l’action d’une NAD(P)H déshydrogénase de type II (NDA2, voie PSII-indépendante). En raison de la sensibilité des hydrogénases à l’oxygène, cette production n’est que transitoire. Bien que ce processus puisse potentiellement réduire notre dépendance aux énergies fossiles, il est à l’heure actuelle économiquement inexploitable compte tenu de sa faible productivité. L’amélioration génétique des microalgues pourrait partiellement remédier à ce problème mais cette stratégie nécessite toutefois de posséder une connaissance fondamentale de toutes les voies métaboliques impliquées dans ce processus spécifique de l’anoxie. Afin d’identifier de nouvelles enzymes clés contrôlant la photoproduction d’H2 et de manière plus générale le métabolisme anaérobique, chez l’algue modèle Chlamydomonas reinhardtii, nous avons cherché dans un premier temps à comprendre la fonction de la protéine NDA3, une NAD(P)H déshydrogénase de type II chloroplastique. A l’instar de NDA2, celle-ci pourrait potentiellement participer à la réduction non-photochimique du pool de plastoquinones. Dans un deuxième temps, nous avons contribué au développement d’une nouvelle technique de criblage «haut débit» basée sur l’enregistrement de la cinétique d’induction de fluorescence des algues lors d’une transition de l’obscurité à la lumière en anoxie. Grâce à l’efficacité et à la rapidité de cette méthode nous avons pu identifier au sein d’une large collection de mutants insertionnels (~ 23 000) quatre mutants déficients pour le facteur d’assemblage HYDG (essentiel à la maturation des hydrogénases) et quatre autres mutants déficients pour la voie de biosynthèse de la phylloquinone. La caractérisation subséquente de ces mutants par des méthodes génétiques, moléculaires, biochimiques et biophysiques, nous a ainsi permis de comprendre in fine l’impact négatif de la perte du facteur HYDG ou de la phylloquinone sur le transfert d’électrons photosynthétique en anoxie. [less ▲]

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See detailIdentification de mécanismes moléculaires d’induction de la réponse immunitaire de type Th2 par les cellules dendritiques conventionnelles CD11b+ du poumon
Janss, Thibaut ULg

Doctoral thesis (2016)

Currently, the activation mechanisms of type 2 helper T cells (Th2) by dendritic cells are not yet fully understood. In recent years, more and more evidences show that there is a functional specialization ... [more ▼]

Currently, the activation mechanisms of type 2 helper T cells (Th2) by dendritic cells are not yet fully understood. In recent years, more and more evidences show that there is a functional specialization of the different dendritic cells populations. Therefore, in our laboratory, it was demonstrated that lung CD11b+ conventional dendritic cells (cDC) are the cells responsible for the allergic sensitization after an inhalation of house dust mite extracts in mice. Because this population is responsible for priming Th2 response, we decided to study them in an allergic context as a model in order to identify new mechanisms involve in Th2 induction. So far, few transcription factors required for the pro-Th2 activity of dendritic cells have been identified. Their discovery could considerably improve the understanding of Th2 activation by dendritic cells. Transcriptomic profiling of lung CD11b+ cDCs exposed to HDM in vivo revealed first that HDM triggered an antiviral defence-like response and second that the majority of HDM-induced transcriptional changes depended on the transcription factor Inresterferon Response Factor-3 (Irf3). Validating the functional relevance of these observations, Irf3-deficient CD11b+ cDCs displayed reduced pro-allergic activity. Indeed, Irf3-deficient CD11b+ cDCs induced less Th2, more regulatory T cell, and similar Th1 differentiation in naïve CD4+ T cells compared to their wild-type counterparts. The altered APC activity of Irf3 CD11b+ cDCs was associated with reduced expression of CD86 and was phenocopied by blocking CD86 activity in wild-type CD11b+ cDCs. Altogether, these results establish Irf3, mostly known for its role in antiviral responses, as a transcription factor involved in the induction of Th2 responses through the promotion of pro-Th2 costimulation in CD11b+ DCs. [less ▲]

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See detailDetection and characterization of transiting hot Jupiters
Delrez, Laetitia ULg

Doctoral thesis (2016)

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See detailLa viande des uns, la faune des autres. Analyse anthropologique de la conservation de la faune dans trois villages Badjoué de la zone forestière de l'Est-Cameroun
Dieudonné, Mélodie ULg

Doctoral thesis (2016)

The Cameroonian forestry and environmental policies adopted in 1994 come within the scope of a will to manage forests sustainably and to involve local populations in the management of their environment ... [more ▼]

The Cameroonian forestry and environmental policies adopted in 1994 come within the scope of a will to manage forests sustainably and to involve local populations in the management of their environment. The aim of this doctoral thesis is to take an anthropological look at the wildlife conservation at the “microsociological” level of three Badjoué villages from the East region while putting these observations in the larger context of Cameroonian forest governance. In what way are wildlife community management measures appropriated, transformed and distorted by the actors? How do interactions between local populations and conservation organizations help transform local contexts and relations to wildlife? By applying an approach at the crossroads of the anthropology of conservation, the anthropology of development and an anthropology of nature which considers human-animal relations in an interactive and dynamic perspective, this thesis aims at paying a particular attention to the relations that the Badjoué of the Dja entertain with their environment, the intertwining of these relations in the local social, economic and political dynamics as well as to the evolution of these problems in the context of the community management of forest resources in Cameroon. The thesis so allows a reflection on the place of participation and local community autonomy in the management of natural resources and a questioning of the impact of coercive models on the environmental practices and conceptions. It finally raises the question of the intertwining between global environmental issues and the necessary consideration of peoples’ right to self-determination. [less ▲]

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See detailL'apprentissage des conversations de conception. Analyse exploratoire des pratiques discursives et graphiques médiées par ordinateur.
Joachim, Guillaume ULg

Doctoral thesis (2016)

A large proportion of architects’ educational and professional activities take place in the form of informal and formal discussions revolving around design artefacts, such as blueprints, sketches and ... [more ▼]

A large proportion of architects’ educational and professional activities take place in the form of informal and formal discussions revolving around design artefacts, such as blueprints, sketches and models. However, there has been little investigation into the multimodal resources mobilized by designers in order to collectively simulate experiments on their projects. In this thesis, we focus on remote mediated-by-computer design conversations in which architects jointly mobilise speech, inscription practices and artefacts handling for the purpose of examining how these function in the negotiation and joint development of architectural design knowledge. On the basis of a cross-cutting theoretical appraisal to the design conversation and on-field observations of remote synchronous meetings between professional designers, this exploratory study aims to describe and define the interactional processes implemented by architects in order to develop a shared reasoning on their project. The cross-disciplinary approach developed in the course of this research results in the formulation of a theoretical and analytical framework for studying the interactional organization behind jointly constructing the meaning of an architectural design. It also offers a better understanding of the fundamental links between graphical and discursive activities in communication between architects, while examining their digital mediations. [less ▲]

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See detailPRODUCTION D’UNE PROTEINE CD40L BOVINE RECOMBINANTE SOLUBLE : UN ADJUVANT VACCINAL POTENTIEL CONTRE LES MAMMITES A STAPHYLOCOCCUS AUREUS
Pujol, Julien ULg

Doctoral thesis (2016)

Staphylococcus aureus est le principal agent responsable des mammites chroniques chez la vache laitière. Malgré les lourdes pertes économiques engendrées et les décennies de recherche sur le sujet, aucun ... [more ▼]

Staphylococcus aureus est le principal agent responsable des mammites chroniques chez la vache laitière. Malgré les lourdes pertes économiques engendrées et les décennies de recherche sur le sujet, aucun vaccin réellement efficace n’a encore été mis au point. Cet échec pourrait être dû à la capacité de survie du pathogène dans les cellules épithéliales mammaires et les phagocytes, où il échappe à l’immunité humorale induite par les vaccins. Les études semblent en effet unanimes sur l’importance majeure de la réponse immune cellulaire, particulièrement la réponse cytotoxique des lymphocytes TCD8+, dans la lutte contre S. aureus. Il a par ailleurs été prouvé, chez les animaux de laboratoire comme chez l’homme, que l’administration de CD40 ligand est un moyen efficace de stimuler cette réponse. Nous avons alors produit, dans un système bactérien et dans des cellules de mammifères, plusieurs formes de CD40L recombinants bovins multimériques. Nous avons ensuite montré leur capacité à activer in vitro le récepteur CD40 de différentes cellules bovines. Enfin, nous avons observé que l’immunisation de bovins avec notre CD40L produit en bactéries, combiné à des bactérines de S. aureus, augmentait significativement le nombre et la réactivité des lymphocytes TCD4+ et TCD8+ spécifiques de celles-ci dans les noeuds lymphatiques. L’évaluation de la protection conférée par l’adjuvant GST-CD40L lors d’une infection intramammaire expérimentale a malheureusement montré l’incapacité de ce nouvel outil moléculaire à prévenir les mammites bovines à S. aureus. Il pourrait cependant rester utile au développement de stratégies vaccinales contre d’autres maladies bovines causées par S. aureus ou d’autres pathogènes intracellulaires. [less ▲]

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See detail"Favorites of the Gods". The Seleucid Kings coping with the divine. A qualitative and quantitative approach of the numismatic evidence attesting the "discreet" divinization of the Seleucids"
Iossif, Panagiotis ULg

Doctoral thesis (2016)

Les Séleucides ont hérité de la plus grande partie du territoire légué par Alexandre le Grand. Leur empire, dans son extension maximale, s’étendait de la Chersonèse de Thrace à l’ouest jusqu’à la ... [more ▼]

Les Séleucides ont hérité de la plus grande partie du territoire légué par Alexandre le Grand. Leur empire, dans son extension maximale, s’étendait de la Chersonèse de Thrace à l’ouest jusqu’à la Bactriane à l’est. Des études récentes ont montré que la population de l’empire a pu atteindre un maximum de 30 millions d’habitants appartenant à différents groupes ethniques et culturels. L’administration de ce vaste territoire multiethnique constituait un véritable défi pour les Séleucides. Il ne fait pas de doute que l’essentiel de leur structure administrative la plus grande part de leur structure administrative provenait directement des Achéménides, mais d’autres aspects plus innovants étaient des créations ad hoc visant à résoudre des problèmes particuliers de la Cour royale et de l’administration. Les deux premiers Séleucides, Séleucos Ier et Antiochos Ier, développèrent une politique coloniale intensive en fondant de nouvelles cités dans l’ensemble des territoires nouvellement conquis. Les nouvelles colonies visaient à marquer physiquement et idéologiquement le territoire et les populations indigènes. Certaines de ces nouvelles fondations devinrent des cités importantes de l’empire, tandis que d’autres restèrent simplement des postes militaires protégeant des zones sensibles. Parmi les premières, Séleucie du Tigre et Antioche devinrent d’importants centres urbains et sont souvent, bien que de manière incorrecte, qualifiées de « capitales ». OBJECTIFS DE LA RECHERCHE La ligne idéologique reliant les différents territoires, populations et groupes ethniques de ce vaste empire n’était autre que le roi lui-même et sa dynastie. Dans cet état de la recherche, nous avons considéré que la figure du roi séleucide était sous-étudiée et relativement marginalisée. Les récentes études ont rarement (voire jamais) posé la question du rôle de la personne royale elle-même en tant que constituant idéologique de l’empire. Son rôle vis-à-vis de et avec le divin est virtuellement ignoré, et le culte royal séleucide n’a jamais fait l’objet d’une étude approfondie. L’analyse iconographique des représentations des rois séleucides n’est jamais allée au-delà de la simple description. Pour ces raisons, dans notre thèse nous avons tenté de répondre aux questions suivantes : quel est le rôle du roi (et de la famille royale en général) dans la création idéologique de ce que nous appelons l’empire séleucide ? Comment ces rois ont-ils envisagé leur relation avec le divin ? Quels dieux ont-ils privilégiés et pour quelles raisons ? Ont-ils jamais tenté de devenir eux-mêmes des dieux, ainsi qu’on peut parfois le lire dans des manuels généraux d’histoire et d’art hellénistiques ? Quels médias les rois (et leur administration) ont-ils de préférence utilisés pour communiquer leur image ? Quels étaient les publics visés ? LA MÉTHODOLOGIE Cette étude est avant tout numismatique, iconographique et religieuse. Cela ne signifie pas que d’autres sources soient exclues de l’analyse, et nous utilisons un large éventail de données archéologiques, épigraphiques et philologiques. La méthode que nous avons adoptée pour répondre aux questions ci-dessus est simple et directe: une analyse exhaustive des données numismatiques établissant un lien entre les rois et le divin et témoignant de la position particulière de la hiérarchie entre les hommes et les dieux. Ces sources numismatiques sont analysées à la fois « quantitativement » et « qualitativement ». Dans un premier temps, nous proposons une analyse détaillée d’une série de questions numismatiques liée à la position des rois en relation avec le divin et/ou leur volonté d’établir une idéologie royale commune. L’impact de ces analyses est ensuite évalué quantitativement à partir de deux bases de données qui ont été établies spécifiquement en vue de cette recherche et se trouve in extenso dans les annexes de la thèse. La première, la « Seleucid Hoard Database » (SHD), réunit virtuellement tous les trésors séleucides, c’est-à-dire tous les trésors contenant au moins une monnaie séleucide. Les données/pièces de monnaie sont étudiées dans les moindres détails afin de permettre à la SHD d’être utilisée pour examiner un large éventail de questions telles que la « quantité relative » de monnaies portant les types d’Apollon ou de Zeus, ou celles présentant le roi avec des attributs divins. La seconde base de données, la « Seleucid Excavations Database » (SED), rassemble le matériel numismatique provenant de fouilles archéologiques et de trouvailles isolées, c’est-à-dire les monnaies trouvées dans des fouilles mais aussi celles qui sont rapportées sans contexte archéologique précis. La structure des deux bases de données est comparable et permet d’obtenir une image représentative de la production monétaire originelle des rois. Ceci dit, nous nous sommes appliqué à démontrer méthodologiquement et statistiquement la représentativité des deux bases de données. Dans ce but, nous avons essayé d’aller au-delà de la simple réunion du « maximum de données possible » afin d’obtenir un échantillon fiable. En ce sens, cette étude s’inspire de la numismatique romaine, et tout particulièrement des analyses proposées par des spécialistes de la (Grande-) Bretagne romaine STRUCTURE DE LA THÈSE La thèse est divisée en quatre parties. Dans la première, nous analysons ce que nous appelons le « contexte du culte royal », c’est-à-dire les sources archéologiques et épigraphiques témoignant d’un culte royal et/ou des relations des Séleucides avec le divin. Le premier chapitre examine les données archéologiques liées au culte royal des Séleucides: naoi (temples), temenoi (enceintes consacrées), autels ou statues des rois. Notre analyse se concentre sur les cultes offerts aux rois par les cités grecques, principalement en Asie Mineure. Le second chapitre analyse les témoignages épigraphiques du prétendu culte « étatique », c’est-à-dire de la façon dont les rois (et leur Cour) se conféraient à eux-mêmes des τιμαὶ (honneurs). Nous examinons en détail le cadre méthodologique des études antérieures concernant la distinction entre culte « civique » et « étatique » avant de nous concentrer sur les fameux prostagmata (ordonnances) de 193 av. n. è. instaurant le culte de la reine Laodicée dans les satrapies du royaume. Le dernier chapitre de la première partie propose une analyse nouvelle de la documentation babylonienne relative au culte du roi et de sa famille. Cette analyse témoigne de l’influence des pratiques grecques sur les rituels locaux en Babylonie et explique pourquoi les rois séleucides participaient activement (et parfois en personne) au festival de l’Akitu. La conclusion de cette première partie introductive est que l’association des Séleucides au divin reste discrète, tant dans les contextes grecs que dans les contextes indigènes. La seconde partie de la thèse introduit l’analyse numismatique et iconographique des données. Il faut toutefois noter que les monnaies ne sont que le point de départ d’analyses plus approfondies dès lors que l’ensemble de données disponibles sont mises à contribution. Dans cette partie nous testons notre thèse principale quant à la « discrétion » des Séleucides lorsqu’ils traitaient avec le divin. Cette thèse est mise à l’épreuve des données visuelles tout en étant discutée à la lumière d’autres sources d’information relatives au rôle du roi séleucide. L’ordre des chapitres est à la fois chronologique et thématique: le premier chapitre examine les toutes premières émissions monétaires de Séleucos Ier portant des attributs divins, i. e. les monnaies de Suse que l’on appelle communément « au trophée ». L’étude de ce monnayage produit par le fondateur de la dynastie dans un atelier monétaire important mais périphérique introduit une série de questions qui seront posées à travers la thèse : pour quelle raison les représentations du roi comportaient-elles des attributs divins ? Quelles étaient la signification et l’importance de ces attributs dans l’idéologie royale ? Comment le roi se positionnait-il en relation avec le divin au moyen de ses représentations numismatiques ? Une grande attention est portée aux détails (par exemple l’episemon du bouclier macédonien au revers, la clef pour comprendre ce monnayage), mais le problème est également envisagé sur le long terme en comparant les données des bases de données SHD et SED. Le second chapitre reste dans le domaine des cornes et introduit la politique taurine et cornue des Séleucides. Nous examinons toutes les données disponibles et arrivons, une fois de plus, à la « discrète » des Séleucides. La même conclusion est obtenue suite à l’analyse d’une petite émission d’un atelier incertain sous Séleucos Ier qui va élargir l’imagerie dionysiaque de la numismatique séleucide. Le chapitre suivant s’intéresse à la signification de l’association du roi avec la représentation d’Apollon assis sur l’omphalos, une image généralement considérée comme la marque déposée de la dynastie. Ce chapitre joue un rôle central dans notre démonstration car il se concentre sur l’ancêtre divin de la dynastie, son archégète, et sur les moyens par lesquels les Séleucides introduisirent et envisagèrent cette filiation au travers de différents médias. Même si une filiation divine semble impressionnante, les rois (et leur administration) s’en servirent d’une façon plutôt « discrète », à la fois dans les sources visuelles et épigraphiques, ce qui suggère que les implications de cette filiation divine étaient discrètes dans l’idéologie royale. Les rois apparaissent comme les « favoris » des dieux, ils sont eusebès (pieux) et jouissent de l’eunoia (bienveillance) divine; ceci est également démontré dans le chapitre suivant où nous focalisons sur un détail un peu marginal : une barbe apparaissant temporairement sur les portraits de certaines émissions monétaires. Ces séries sont liées à des vœux faits par les rois ; une fois de plus, le roi s’associe et se rattache au divin d’une façon « discrète », que nous osons aussi dire « personnelle ». Cette discrétion est aussi discutée lorsque nous considérons une série de monnaies montrant le buste royal drapé. Les chapitres précédents ont insisté sur le caractère subtil de l’association de Séleucos Ier et Antiochos II avec le divin. L’analyse de l’imagerie céleste d’Antiochos IV et de ses successeurs démontre que la situation change sous le règne de l’Epiphane. Antiochos IV s’associe en effet avec le divin d’une manière plus flagrante, usant (et abusant)des attributs divins sur ses portraits. La suite de l’étude suggère cependant que sa politique était beaucoup plus nuancée par rapport à ce qu’affirment certaines études. L’analyse de la circulation et du volume des émissions monétaires nous permettent en effet de réévaluer la politique d’Antiochos IV, et de comprendre que le roi n’était pas, après tout, moins « discret » que ses progonoi, mais qu’il tentait simplement de s’adapter au problème critique de son époque, c’est-à-dire l’arrivée d’un nouveau et important compétiteur en Méditerranée orientale, Rome. Le dernier chapitre de la seconde partie de notre thèse examine la relation des reines avec le divin au travers de l’analyse d’une émission de petits bronzes frappés dans l’est et l’ouest de l’empire. Il apparait que les reines séleucides étaient associées de manière préférentielle avec la déesse Aphrodite, une divinité autrement marginale parmi les types monétaires séleucides. Le chapitre suivant introduit la troisième partie de la thèse, laquelle correspond à l’analyse quantitative des données numismatiques (et sigillographiques). Notre analyse offre une démonstration méthodologique de la fiabilité, de l’utilité et des perspectives futures des bases de données SED et SHD. Les analyses de ces deux bases de données sont les plus détaillées possibles, car il s’agit d’une toute nouvelle méthode en numismatique grecque. C’est pourquoi les bases de données sont testées au moyen de méthodes statistiques. Cela mène l’analyse à quelques conclusions surprenantes concernant, par exemple, le volume des productions monétaires et le niveau de monétarisation des Séleucides et des Ptolémées, ou le rapport étroit observé en comparant la SED et la SHD aux plus grandes collections numismatiques du monde. En vue de ces études comparatives, plus de 25.000 pièces de monnaie appartenant à cinq collections majeures ont été examinées, ce qui donne à nos bases de données et à leur usage dans le futur un poids supplémentaire. Après la démonstration de la fiabilité des bases de données, les trois chapitres suivants se concentrent sur la question principale de la thèse: à quel point la relation des Séleucides avec le divin était-elle « discrète » ? Nous y répondons d’abord en analysant les monnaies appelées « divines », c’est-à-dire les pièces où le roi est décrit portant un ou plusieurs attributs divins. Le résultat est surprenant : pas plus de 30 pourcents des monnaies séleucides portent un type divin. Ce pourcentage est même plus faible lorsque l’on prend en considération les paramètres du métal, de la circulation et de la chronologie. En tout cas, une fois de plus, nous constatons que les Séleucides hésitèrent à s’associer au divin de manière plus ostentatoire. Ce résultat, un simple nombre, a des conséquences importantes pour la compréhension de l’idéologie royale et religieuse, et pour déterminer les publics visés par ces médias visuels. L’analyse comparative des données numismatiques et des données sigillographiques de Séleucie du Tigre sert d’étude de cas pour identifier les différentes audiences visées par les différents types de communication visuelle. Dans tous ces cas, il est évident que les rois séleucides n’affirmèrent jamais réellement un statut divin ; ils restèrent des rois eusebès, les « favoris des dieux », voulant simplement afficher soit leur piété, soit la faveur divine dont ils bénéficiaient, plutôt que leur (supposé) statut divin. L’étude comparative et diachronique des représentations d’Apollon et de Zeus montre également que les monnaies, en tant que documents officiels, étaient l’expression de politiques précises, déterminées et ciblées. L’évolution de l’iconographie numismatique de Zeus à Apollon et puis de nouveau à Zeus ne fut pas une question de goût personnel, mais l’expression visuelle de la naissance d’une dynastie et des luttes internes de cette dynastie, tout particulièrement après la défaite de Magnésie du Méandre en 189 av. n. è. Le court chapitre suivant vise à démontrer les possibilités offertes par les bases de données SED et SHD. Dans cette optique, nous avons choisi, d’une manière assez provocante, de comparer la vitesse de circulation de la monnaie dans la zone Euro et l’empire séleucide. Le résultat est surprenant mais montre clairement les nombreuses perspectives offertes par la création de grandes bases de données. Le chapitre de conclusion est consacré à ce que nous considérons comme la scène idéale pour l’étalage de la magnificence royale séleucide: la procession de Daphné organisée par Antiochos IV. L’analyse de ce cortège met en évidence la manière dont ce roi voulait être perçu par ses sujets et par les représentants étrangers (les theoroi) et désirait se positionner dans la dichotomie entre l’humain et le divin. En conclusion, dans cette thèse, nous examinons le roi séleucide face au divin en nous concentrant sur les expressions visuelles des médias produits par le roi lui-même (et son administration). C’est la démarche du sommet vers la base (top-to-bottom) qui nous intéresse. Le roi et sa Cour mirent en scène une idéologie et une politique communes : la façon dont le roi doit être vu et perçu par ses sujets et les dynasties hellénistiques rivales. Au cours de ce processus, le roi (et sa Cour et son administration) restèrent très prudents ; ils ne franchirent jamais la ligne rouge séparant les sphères humaine et divine. Ils préférèrent toujours mettre en valeur leur piété envers le divin plutôt que leur hypothétique nature divine. Les rois préférèrent afficher leur position en tant que favoris des dieux plutôt que prétendre être des dieux eux-mêmes. Il leur importait plutôt de revendiquer leur victoire (espérée ou obtenue) en exprimant leur position unique de « favoris des dieux ». C’est cela que les données numismatiques donnent à voir et c’est ce qu’Antiochos IV mit en scène lors de la procession de Daphné. La thèse porte le titre parlant de « Favoris des dieux ». La raison en est simple: être les préférés des dieux était la seule position que revendiquaient les rois séleucides. Ils étaient les fils d’Apollon, mais par-dessus tout, ils exprimaient leur piété envers le divin ; et comme ils étaient des rois pieux, ils pouvaient être les favoris des dieux. C’est là le message politique, idéologique et religieux qu’ils élaborèrent et communiquèrent. On peut observer que c’était un message plutôt subtil, discret et efficace, puisque la piété est une valeur commune à toutes les religions et que pour cette raison elle devait être comprise par les différents sujets de leur immense empire. Nous avons soutenu la thèse que le roi séleucide n’est pas dieu, que jamais il n’a souhaité exprimer sa propre divinité et/ou ne s’est présenté comme tel. Il se servait des attributs divins comme de marqueurs visuels de son eusebia, sa piété, et pour afficher sa position de « favori des dieux ». [less ▲]

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See detailOn the GMP production of [18]FUCB-H : Imaging neurotransmission
Warnier, Corentin ULg

Doctoral thesis (2016)

We herein describe the straightforward synthesis of a stable pyridyl(aryl)iodonium salt and its [18F]radiolabelling within a one-step, fully automated and cGMP compliant radi-osynthesis of [18F]UCB-H, a ... [more ▼]

We herein describe the straightforward synthesis of a stable pyridyl(aryl)iodonium salt and its [18F]radiolabelling within a one-step, fully automated and cGMP compliant radi-osynthesis of [18F]UCB-H, a PET tracer for the imaging of Synaptic Vesicle glycoprotein 2A (SV2A). Over the course of one year, 40 automated productions provided 34±2% of injectable [18F]UCB-H from up to 7.7 Ci of [18F]fluoride in 50 minutes (uncorrected radiochemical yield. Specific Activity = 22±5 Ci/µmol). The successful implementation of our synthetic strategy within routine, high-activity and cGMP productions attests to its practicality and reliability for the production of large doses of [18F]UCB-H. In addition to enabling efficient and cost-effective clinical research on a range of neurological pathologies through the imaging of SV2A, this work further demonstrates the real value of iodonium salts in the cGMP 18F-PET tracer manufacturing industry and their ability to fulfill practical and regulatory requirements in that field. [less ▲]

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See detailMécanismes moléculaires associés à l’induction de la pathogénicité chez Streptomyces scabies
Jourdan, Samuel ULg

Doctoral thesis (2016)

Streptomyces are filamentous soil-dwelling bacteria that actively participate in the mineralization of dead organic matter. Members of this bacterial genus are commonly known for the plethora of secondary ... [more ▼]

Streptomyces are filamentous soil-dwelling bacteria that actively participate in the mineralization of dead organic matter. Members of this bacterial genus are commonly known for the plethora of secondary metabolites of interest they secrete. Predominantly saprophytes, some Streptomyces species have been proved to be phytopathogenic. The most widespread and best characterized of these species is Streptomyces scabies which is the causative agent of the common scab disease that affects the underground organs of many plants with a preference for storage organs such as potato tubers or pivot roots (beet, turnip, carrot, etc.). Common scab is characterized by brown and corky lesions on the infected organs and causes significant economic losses around the world. The pathogenicity of S. scabies is directly related to its ability to produce the phytotoxin thaxtomin. Unveiling when, how and why S. scabies triggers the production of its phytotoxin is therefore of major interest to understand phytopathogenicity and the virulence associated with this bacteria. Previous works identified cellobiose as the main elicitor of thaxtomin production. However, no signaling pathway from the sensing of the eliciting signal to the biosynthesis of thaxtomin has been proposed so far. The aim of this work is to elucidate the molecular mechanisms involved in the onset of thaxtomin production in the model species S. scabies. In this work we highlighted the central role of the cellulose utilization transcriptional repressor CebR in S. scabies pathogenicity. Indeed, we showed that this regulator directly controls the expression of thaxtomin biosynthesis genes, but also the expression of genes involved in sensing, transport and catabolism of cellooligosaccharides. Together, our results allow to propose a first signaling pathway from cellooligosaccharide transport to the production of thaxtomin in S. scabies, with each step of the cascade controlled by CebR. The results obtained in the course of this thesis extended well beyond the fundamental research scope of elucidating the mechanisms associated with the onset of virulence of S. scabies. Indeed, assessed if/how our findings could propose solutions to current industrial biotechnology iapplications, i.e. i) to provide a mutant that constitutively produce thaxtomine could improve the production yields of this promising bioherbicide, and ii) to assess the enzymatic characteristics of a Beta-glucosidase of S. scabies as possible candidate in lignocellulose saccharification processes. [less ▲]

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See detailHydrodynamics and bed stability at smooth-to-rough transitions. Experiments based on acoustic flow measurements
Duma, Diana ULg

Doctoral thesis (2016)

As reflected in the scale of large contemporary hydropower schemes, flowing water may carry huge amounts of energy. If not mastered properly, this energy may cause impressive channel erosion and local ... [more ▼]

As reflected in the scale of large contemporary hydropower schemes, flowing water may carry huge amounts of energy. If not mastered properly, this energy may cause impressive channel erosion and local scour. Therefore, one lasting concern in hydraulic engineering has been the stability of structures, riverbeds and riverbanks against flow erosion. Two main limitations of current understanding of riverbed and riverbank stability are highlighted: the first one is directly linked to the evaluation of the flow action, while the second one relates to the conceptual framework in which stone stability is evaluated. Since the standard approaches use the mean bed shear stress to quantify the flow forces, they may only apply under uniform flow conditions, for which the ratio of turbulence intensity to the bed shear stress remains almost constant and the influence of turbulence is therefore implicitly incorporated. For non-uniform flow, correction factors have been conventionally applied to account for the turbulence fluctuations; but this approach does not reproduce the physical influence of turbulence higher in the water column and can only be used as a rule of thumb. A new approach was initiated recently in literature. Instead of using the standard Shields parameter, it quantifies the flow forces by means of a new set of parameters which combine explicitly the velocity and turbulence distributions over a certain water depth above the riverbed, while remaining reasonably accessible for engineering applications. Next, this quantity is related to a mobility parameter, which describes the bed damage. This new approach requires additional high quality experimental data to confirm its validity for a wider range of non-uniform flow. In this research, the focus was set on a single canonical configuration, namely a smooth-to-rough transition. We take a preventive perspective by focusing on the flow and bed stability conditions before a scour hole starts to develop and we are interested in characterising the flow conditions to ensure bed stability, i.e. prevent the dislodging of bed material downstream of the structure. As a second specific objective of the thesis, we aimed at evaluating the feasibility of using acoustic techniques to properly estimate the new bed stability parameters proposed in literature in the last decade and draw conclusions on stone mobility at smooth-to-rough transitions. The experimental tests were conducted in two laboratory flumes, a horizontal bottom flume (6 m long and 15 cm wide) and a tilting flume (up to 4% slope, 20 m long and 50 cm wide), in which we measured the flow velocity at a 100 Hz frequency, using two different acoustic instruments: an Ultrasound Velocity Profiler (UVP) and a 3D Acoustic Doppler Velocity Profiler (ADVP). The measurements were done immediately downstream of the transition from smooth-to-rough. Two types of tests were undertaken. In the first type, the stones were glued with silicone on the flume bottom and velocity measurements were performed without stone motion. This enables measurements of the flow characteristics both below and above the threshold for inception of sediment motion, without perturbations induced by stone displacements. In the second type, the stones in the measurement area were laid on the bottom of the flume (i.e. not glued) and the number of entrained stones was recorded. The tests were conducted by varying (i) the grain size of the bed material (8 mm, 15 mm and 30 mm), (ii) the flow velocity (between 0.74 m/s and 1.16 m/s), (iii) the sediments density (1410 kg/m³, 1690 kg/m³ and 2650 kg/m³) and (iv) the configuration (quasi-uniform vs. smooth-to-rough transition). Indeed, for the purpose of comparison, a uniform rough bed (quasi-uniform configuration) was considered also, by replacing the smooth part of the bed with similar sediments as in the measurement area. After a specific signal processing, flow variables were derived from the measurements and were next exploited to evaluate several bed stability parameters, with the aim of correlating them with bed damage data obtained from dedicated experiments. The results showed no correlation between the bed damage and the bed shear stress or between the bed damage and flow turbulent kinetic energy. In contrast, when the flow action is described by both mean velocity and turbulence characteristics, a relative good correlation with the bed damage was observed. Nonetheless, these correlations appear only per subset of points corresponding to the same grain size and/or same material density or flume geometry. With a total of 45 hydraulic configurations for which the flow characteristics were measured and 66 (times four repetitions) tests in which the bed damage was observed, the present research ends up with a unique dataset, which may prove useful in various research such as for the validation of 2D-vertical and 3D turbulent flow and morphodynamic simulations. Another key outcome of the present doctoral research is a systematic comparison between measurements conducted with the UVP and the ADVP. The ADVP is deemed generally more accurate and reliable. Nonetheless, both instruments remain somehow complementary. We showed that, under certain conditions, the considered instruments have the potential to contribute to the assessment of bed stability in the considered configurations. [less ▲]

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See detailDevelopment of alternative methods to control aphids (Hemiptera: Aphididae): from wheat-pea intercropping to the use of semiochemical dispensers
Chevalier Mendes Lopes, Thomas ULg

Doctoral thesis (2016)

Increasing the sustainability of food production is a major challenge in today’s agriculture. Several practices can be implemented to reduce the use of external inputs such as agrochemicals. In terms of ... [more ▼]

Increasing the sustainability of food production is a major challenge in today’s agriculture. Several practices can be implemented to reduce the use of external inputs such as agrochemicals. In terms of insect pest control, the concept of integrated pest management (IPM) has been exploited to minimize the application of chemical insecticides. The idea is to limit pest infestations while promoting their control by natural enemies. One possibility is to increase within crops plant diversity namely by intercropping. Semiochemical dispensers may also be used to attracted natural enemies into crops. Focusing on wheat (Triticum aestivum Linnaeus), several types of intercropping can be practiced with variable effects on pests and natural enemies. This PhD thesis focuses on the potential of wheat-pea (Pisum sativum Linnaeus) intercropping as a way to reduce aphid (Hemiptera: Aphididae) infestations. We firstly assessed the diversity of aphid and their parasitoid species in wheat and pea fields using yellow pan traps and in situ observations on plants. Whether several aphid species were trapped, only Sitobion avenae (Fabricius), Metopolophium dirhodum (Walker), Rhopalosiphum padi (Linnaeus) and Acyrthosiphon pisum (Harris) were found on wheat tillers and pea plants respectively. Regarding parasitoids, some species can use wheat and/or pea aphids as hosts. The first Belgian parasitoid species checklist was established, with the inclusion of four Aphidiinae (Hymenoptera: Braconidae) and three Aphelinus (Hymenoptera: Aphelinidae) species as new records. In terms of abundance, we firstly compared the effect of two types of wheat-pea intercropping (mixed and alternate strip cropping) on aphids and their natural enemies with pure stands of both crops. The mixture was particularly efficient to reduce pea aphid populations, while alternate strips were more suitable for the control of wheat aphids. However, natural enemies were more abundant in the pure stands, showing that additional methods may be needed to attract them more efficiently. One possibility is the use of semiochemicals dispensers. In another field study, we combined a wheat-pea mixture with methyl salicylate (MeSA) dispensers. This substance was selected due to its known attractive effect towards some aphid beneficials. Even though adult hoverflies (Diptera: Syrphidae) were not particularly attracted by the mixture combined with MeSA dispensers, they may have stimulated their oviposition behaviour. Also, mummified aphids were significantly more abundant in the pure stand of pea compared with the mixture (with and without MeSA). However, parasitism rates did not differ significantly between treatments. Beneficial effects of wheat-pea intercropping were clearly demonstrated for aphid control. Other agronomic aspects make this practice particularly interesting in low-input farming systems. These are discussed, along the limitations related to the use semiochemicals in field conditions. Perspectives for further research works are also proposed. [less ▲]

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See detailStructure and Dynamics of Ge-Se Liquids and Glasses under Pressure
Yildirim, Can ULg

Doctoral thesis (2016)

Among network forming glasses, chalcogenide glasses are of great importance not only for their optoelectronic applications, but also for the network structure that displays enhanced structural variability ... [more ▼]

Among network forming glasses, chalcogenide glasses are of great importance not only for their optoelectronic applications, but also for the network structure that displays enhanced structural variability due to the covalent bonding network. In this project, we study the Ge-Se binary alloy as the target system in order to investigate the structure and dynamics of the liquid and glassy phases under pressure by using a combination of ab initio molecular dynamics (AIMD) simulations and X-ray scattering experiments. The wide glass forming range of the GexSe100􀀀x system allows one to tune the stiffness of the network structure by increasing the mean coordination number with the Ge content which affects the macroscopic material properties such as resistance to aging, hardness, conductivity, and fragility. In this respect, we study 10 different AIMD generated and 5 experimentally produced (i.e melt quenching) compositions spanning the flexible-to-rigid elastic phase transitions according to Maxwell’s isostatic stability criterion. As for the liquid state, after having validated the structural models by comparing the experimental findings available, we examine the dynamics of Ge-Se melts at ambient pressure. The investigations on the diffusion coefficients and viscosity at 1050 K showed clear anomalies, departing from the expectation that atomic mobility should decrease as the system becomes more and more rigid. Furthermore, the relaxation behavior at 1050 K also shows similar anomalies when intermediate scattering factors are examined at q vector corresponding to the principal peak position of the total structure factor. To elucidate this anomaly, we discuss the effect of the topological constraints on the dynamics in liquid state. The results show that the isostatic systems have slower dynamics as compared to flexible and stressed rigid phases. Moreover, we speculate that the reason of this anomaly may originate from the distribution of the topological bond bending constraints of the higher coordinated species (i.e. Ge) results. In particular, the flexible, and stressed rigid compositions showed a high variance in the Ge bond bending constraints whereas the isostatic composition forms a network in which the bond bending constraints are homogeneously distributed. We link this behavior with a global fragility concept for network forming liquids in such a way that fragility minima are obtained both by experimental findings and the calculated fragility values of the AIMD generated compositions (i.e. VFT or MYEGA fits) when scaled to the isostatic composition for a number of different systems. As for the glassy phase, the AIMD generated structural models show good agreement in both real and reciprocal space. The equation of state and normalized stress-strain curves are compared to the available experiments in order to verify the pressure behavior of the simulations. The results show a good agreement. In addition to the simulations under pressure, we show results of X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) experiments under pressure. Both simulations and the experiments show that there are no sign of crystallization during compression up to 42 GPa. One of the main important finding is the evolution of the Ge-Se bond length for the compositions studied. We observe a bond compression in the early stages of densification in the phase identified as low density amorphous (LDA), which is followed by an abrupt jump starting in pressures around 10-15 GPa, both in simulations and experiments. Furthermore, a semiconductor to metal transition is identified with the red shift in Ge K edge energy. The features of polyamorphism was also detected from the pressure evolution of the principal peak position of the structure factor which show two distinct slopes indicating different structural response to the applied pressure. In order to have a deeper understanding of the densification mechanisms, we apply neighbor analyses to our atomic trajectories and show that the tetrahedral to octahedral transformation (i.e LDA to HDA) starts to take place when the fifth and sixth neighbors effectively become the part of first shell neighbors, where the bond angles adapt themselves to 90 degrees. We furthermore speculate the effect of network rigidity of the glasses at ambient conditions onto the kinetics of the amorphous-amorphous transitions. It appears that the polyamorphic transitions are more sluggish as the network rigidity (i.e Ge content) increases. Finally we show that there is a universal threshold value in coordination change from LDA to HDA phases GexSe100􀀀x (where x 25) when scaled to reduced densities. [less ▲]

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See detailREFINEMENT OF PERI-ANAESTHESIA PRACTICES FOR LABORATORY ANIMAL CARE
Thomas, Aurélie ULg

Doctoral thesis (2016)

Life sciences (i.e. fundamental science, translational medicine, pharmaceuticals) represent a major strategic market in Europe. The industry is highly innovative and dynamic but continues to rely on the ... [more ▼]

Life sciences (i.e. fundamental science, translational medicine, pharmaceuticals) represent a major strategic market in Europe. The industry is highly innovative and dynamic but continues to rely on the use of laboratory animals to model most human diseases. Russell and Burch first enounced the principles of the 3Rs (Replacement, Reduction, and Refinement) in 1959. The 3Rs summarise the ethical compromises appended to the use of any laboratory animal for medical of scientific advancements and have as such been thoroughly quoted in all contexts relating to the use of animals in research—e.g., in laws, policies, ethical statements, textbooks. The work presented in this thesis is especially concerned with the concept of refinement, defined as “any decrease in the incidence or severity of inhumane procedures applied to those animals which still have to be used”. The control of pain and distress by appropriate use of anaesthetic and analgesic agents represents a major aspect of the refinement of research procedures. This last statement, while simple, does not fully translate into the reality of pain and distress management for laboratory animals. While anaesthesia is near-always used when indicated, chosen anaesthetic agents or inappropriate per-anaesthesia monitoring might indirectly contribute to increasing morbidity, mortality, or inter-individual variations. An inevitable consequence is an increase in the required sample size, contradicting the principle of reduction. Additionally, only a minority of small mammals receives appropriate analgesia after experimental surgical procedures. Pain, or the lack of standard pain relief strategy would further exacerbate unwanted variations between subjects. Perceived technical difficulties, fear of unwanted interactions of anaesthetic and analgesic agents with the primary aims of the procedure, and failure to identify animals in pain are commonly quoted to justify such sub-optimal refinement of scientific procedures. The objectives of the present thesis were to: (1) Describe the impact of non-binding guidelines on peri-anaesthesia practices in laboratory animal care; (2) Document the practicality and efficiency of refined anaesthesia, analgesia and euthanasia techniques routinely performed in laboratory animal procedures; (3) Contribute to the development of a pain assessment method for laboratory animals. The scientific contributions from this thesis are:  Non-binding guidelines such as the Stroke Therapy Academic Industry Roundtable (STAIR) guidelines did not succeed in changing peri-anaesthesia practice in rat stroke models.  The vast majority of rats undergoing surgery for cerebral ischemia models are not intubated or mechanically ventilated. Abstract of the thesis 10  Endotracheal intubation of small mammals such as marmosets is straightforward and can be performed with readily available materials (over-the-needle catheter and Silastic tubing); it should be part of standard anaesthetic care.  When concerns surround the use of systemic opioids for analgesia, the intrathecal route could be considered in rodents. Transcutaneous administration of morphine (L6-S1) is easily performed (82% success at 1st attempt) in anaesthetised rats using cheap and readily-available material (hypodermic 25G needle and syringe), and provides analgesia for up to 8 h (acute surgical pain).  Adding N2O to a rising concentration of CO2 (60 % and 20 % of the chamber volume per minute) shortens the time to loss of consciousness by 10 % in mice being euthanised, without any behavioural sign of distress. Nitrous oxide may therefore reduce the duration of any stress or distress to which mice are exposed during euthanasia.  Rabbits experience pain during the tattooing process. Variation of facial expressions can be used as a means to identify acute pain in rabbits using a Rabbit Grimace Scale. The refinement of peri-anaesthesia techniques is both possible and effective (Studies II-VI), and their impact on the welfare and quality of life of laboratory animals is discussed. Given that attempts to improve animal welfare by merely adopting legislation and guidelines (Study I), and hoping for their implementation at a scientific level have only returned disappointing results, other approaches are further discussed as perpective for future refinement of laboratory animal use. [less ▲]

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See detailSynthesis of poly(ionic liquid)-type nanogels, by cobalt-mediated radical cross-linking copolymerization for coating applications
Weiss-Maurin, Mathilde ULg

Doctoral thesis (2016)

To answer the increasing demand for long-lasting antibacterial polymeric coatings, this thesis explores a straightforward synthetic approach to cationically charged nanogels by cobalt-mediated radical ... [more ▼]

To answer the increasing demand for long-lasting antibacterial polymeric coatings, this thesis explores a straightforward synthetic approach to cationically charged nanogels by cobalt-mediated radical cross-linking copolymerization (CMRCcP), thus expanding previous works on the cobalt-mediated radical polymerization of poly(ionic liquid)s, or PILs. This method involves a vinyl monomer and a divinyl cross-linker, in presence of a complex of Cobalt(III) playing the role of both the initiator and the controlling agent. The syntheses of globular nanogels were first investigated under mild conditions, using a mono- and a divinyl co-monomer with similar reactivities. CMRCcP was implemented on either neutral (vinyl acetate (VAc) and divinyl adipate (DVA)) co-monomers, or hydrophilic (bromide-containing) ionic liquid co-monomers. Control over each polymerization was ascertained, and dormant cobalt-carbon chain-ends could be re-activated to form “second-generation” nanogels. CMRCcP of N-vinyl-3-ethyl imidazolium bromide (VEtImBr) and 1,13-divinyl-3-decyl diimidazolium bromide (DVImBr) was achieved in water at 30 °C, leading to hydrophilic poly(VEtImBr-co-DVImBr) nanogels. The antibacterial activity of these cross-linked structures was investigated, and an effect of architecture is detected. The hydrophobic pendants of these PIL-based nanogels were synthesized via direct CMRCcP in ethyl acetate, using bis(trifluromethanesulfonyl)imide (NTf2-) counter anions. An array of these poly(VEtImNTf2-co-DVImNTf2) nanogels was then investigated as possible coatings for porous patterned surfaces. Thin films of hydrophobic PIL-based nanogels were also evaluated in ionic conductivity tests. “Second-generation” nanogels exhibited better ionic conductivity, and were able to form better organized porous patterned surfaces than “first-generation” nanogels. Different cross-linked architecture were approached, using a mono- and a divinyl co-monomers of completely different reactivities: synthesizing poly(VEtImBr-co-DVA) nanogels met limited success, while copolymerizing VAc and DVImBr yielded too low conversion. A two-step arm-first process was implemented to form star-like poly(VEtImNTf2-co-DVImNTf2) nanogels with PVAc arms. [less ▲]

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See detailDealing with storm impacts on the forest sector through integrated and systemic approaches at the regional level
Riguelle, Simon ULg

Doctoral thesis (2016)

Wind is one the most damaging natural hazard that forests are facing worldwide and in Europe. Destructive storms lead to severe forest damage and consequently cause disruptions in daily forest management ... [more ▼]

Wind is one the most damaging natural hazard that forests are facing worldwide and in Europe. Destructive storms lead to severe forest damage and consequently cause disruptions in daily forest management and timber supply chains. Major dysfunctions can happen at each step of forest-wood chains and at each level of management, leading to huge economic losses and long-lasting crises within public organisations and private companies. In this context, the first part of this work aims at handling those complex and multi-facetted storm-related issues with new approaches in order to mitigate economic, environmental and societal impacts of storms on the forest-based sector. In a first step, an overview of risk management practices in forestry is presented, as well as major determinants of storm damage risk management. SWOT analyses are also used for highlighting main issues and opportunities in current windthrow management process. In a second step, an integrated framework is proposed for tackling those strategic issues and seizing opportunities arising from the uncertain decision-making context. A systemic perspective is also presented for managing storm damage risk at regional, national or supranational level with a holistic perspective. In regards to those original approaches, the thesis also highlights some of the crucial challenges public authorities might address for enhancing their affectivity in this process. In the second part of the manuscript, three particular aspects of storm damage management are considered: contingency planning, the development of decision-supporting tools for the forest community, and timber storage planning at the regional level. Those topics are illustrated by case studies taking place in Wallonia, Belgium. In particular, the development of a model-based decision support system (DSS) illustrate how systemic analysis can help on the one hand designing balanced strategies for the regional forest-based sector in case of severe wind damage and on the other hand identifying bottlenecks that should be solved before the next huge storm to enhance systemic resilience and resistance. Regarding timber conservation, a GIS-based methodology for locating optimal areas for sprinkling storage at the regional scale is presented, together with an applied study on the influence of anaerobic storage process on the quality of spruce logs. From a wider perspective, this thesis reveals that taking decision under uncertainty will remain a key challenge to address in forestry, especially in the context of climatic change. However, original methodologies focusing on systemic and integrated risk management approaches can help in this effort. Finally, the work emphasises the urgent need of effective risk management policies at regional, national, and international levels to guide researchers, forest managers and industrials. [less ▲]

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See detailDevelopment and validation of analytical methods for quantifying isoflavones and equol in biological matrices
Daems, Frédéric ULg

Doctoral thesis (2016)

Isoflavones are natural plant substances that attract widespread interest because of their association with a large variety of beneficial effects on human health. When they are ingested by animals or ... [more ▼]

Isoflavones are natural plant substances that attract widespread interest because of their association with a large variety of beneficial effects on human health. When they are ingested by animals or humans, most of these compounds are metabolized by bacteria present in the digestive system. Among the isoflavone microbial metabolites, equol is probably the most widely studied because it seems to have numerous health benefits. In the human population, however, not everyone is able to produce equol. Equol enrichment of some food, such as cow's milk, could be an alternative strategy for making equol’s health benefits available to everyone. The main objective of the present thesis was to develop analytical tools for quantifying these compounds in several biological matrices, thus contributing to the feasibility study being conducted on producing milk naturally enriched with equol. For this purpose, four analytical procedures, using ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC®-MS/MS), were developed and fully validated. The analytical tools were then applied successfully in two original exploratory studies that sought to quantify equol concentrations in commercial cow's milk in Belgium and study the evolution of isoflavone concentration in red clover (Trifolium pratense L.) silage in laboratory-scale silos. This thesis describes new and reliable analytical tools that will help to improve current knowledge about the feasibility of producing cow's milk naturally enriched with equol and to study isoflavone metabolization in dairy cow. [less ▲]

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See detailPerformance de l'indicateur Azote Potentiellement Lessivable pour l'évaluation de la gestion du nitrate en agriculture et du risque pour la qualité de l’eau
Vandenberghe, Christophe ULg

Doctoral thesis (2016)

Since the end of last century, the nitrate concentration in groundwater has steadily increased in Wallonia as in other parts of Europe, particularly in regions where agriculture is intensively practised ... [more ▼]

Since the end of last century, the nitrate concentration in groundwater has steadily increased in Wallonia as in other parts of Europe, particularly in regions where agriculture is intensively practised. In response to this, Europe developed a ' Nitrates ' directive in 1991 that each member state had to transcribe in its legislation. In the Walloon region, the transcription took the form of a Sustainable Nitrogen Management Program (PGDA). This program provides among others control of farms through the analysis of nitrate nitrogen soil residue, in autumn, the beginning of the leaching period of nitrate. This measure is commonly referred to as APL for ‘Potentially Leachable Nitrogen’. The results are assessed by comparison to references established annually based on observations in plots where PGDA is applied and where fertilization recommendations are based on nitrogen balance. In case of non -compliance, the farmer has to follow an observation program, or even to pay a fine. The aim of the thesis is to evaluate the performance of the APL as agronomic (nitrogen management) and environmental indicator (risk to groundwater quality). On the agronomic side, through experimentations or treatment of field APL controls, it has been demonstrated that the indicator was well correlated with fertilization practices and intercrop management. The performance of the indicator has been validated. Some uncertainty factors (intra-plot variability, temporal variability, bulk density, stone content) were quantified. Finally, the influence of soil physicochemical properties on the APL was studied and discussed. The performance of the APL control was also discussed and improvements to regulation have been proposed. On the environmental side, through observations made during a decade in plots equipped with a lysimiter or in a small watershed, the dependence of the nitrate concentration in water (at the base of the root zone or in aquifer) to the APL has been demonstrated. It therefore appears that the APL can be used to firstly assess the reality of the sustainable nitrogen management in controlled farms and also to validate or, if necessary, complete the PGDA to make it more efficient for water quality preservation / restoration. [less ▲]

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See detailRadiosynthesis and preclinical development of [18F]labeled tryptophan for human indoleamine 2,3-dioxygenase PET imaging
Henrottin, Jean ULg

Doctoral thesis (2016)

Nowadays, Cancer is probably the global incidence disease which is the most widespread, the most varied, still constantly rising and that can affect all levels and social classes of the population. Its ... [more ▼]

Nowadays, Cancer is probably the global incidence disease which is the most widespread, the most varied, still constantly rising and that can affect all levels and social classes of the population. Its treatment and care of patients suffering from this disease made it undoubtedly a crucial medical and scientific challenge, but also and above all, a major political, economical and social challenge for the coming years. Since its early detection often leads to a positive prognostic for the future of the patient, numerous methods are currently being developed to make easier its screening and improve its treatment. Positron Emission Tomography (PET) is one of the best techniques used to diagnose and bring out the presence of tumor cells, but also to study enzymatic activities within them, allowing therefore the prescription of a more adequate treatment and better tailored to each individual patient. That’s in this spirit that a novel specific radiotracer of the human indoleamine 2,3-dioxygenase enzyme (hIDO) has been developed during this PhD thesis. This enzyme, highly expressed in numerous human tumors, is also currently subject to the development of various inhibitors. This report presents the development of N1-(2-[18F]fluoroethyl)-L-tryptophan (1-[18F]FE-L-Trp), a novel PET radiotracer derived from L-tryptophan and bearing a radioactive atom of fluorine-18 ([18F]F). This “story” starts with the synthesis of this compound and its selection as a specific substrate of hIDO among several potential candidates, and continues until its in vivo PET imaging on mice, while including also its enantiomerically pure and automated radiosynthesis, and numerous in vitro enzymatic and cellular assays, demonstrating the properties and the characteristics (specificity and selectivity) of this radiotracer with respect to hIDO. According to this study, in vitro cellular uptake have demonstrated that 1-[18F]FE-L-Trp is a radiotracer of choice to facilitate the development and the preclinical validation of novel potential inhibitors of hIDO (e.g. 1-methyl-L-tryptophan). Additionally, some in vivo PET imaging on mice bearing one tumor in each flank have shown that this radiotracer allows the in vivo detection of tumors expressing this enzyme. Nevertheless, in the conditions tested until now, only very small preferential uptake was observed with this radiotracer, in hIDO expressing tumors as compared to hTDO and control tumors. As a result, this radiotracer cannot be yet considered as a PET contrast agent in this animal model. Therefore, further additional investigation will be required to understand and characterize this animal model, to improve these in vivo results, and finally reach this objective. However, this PhD research constitutes the first step towards the preclinical development of radiopharmaceutical compounds allowing the molecular cancer imaging through the intermediary of hIDO enzyme. [less ▲]

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See detailMix and match: Essays on collective dynamics in nascent social entrepreneurship
Dufays, Frédéric ULg

Doctoral thesis (2016)

Social entrepreneurship is increasingly recognized both in research and practice as a form of entrepreneurship that is inherently hybrid as it combines a social-welfare logic with a commercial logic at ... [more ▼]

Social entrepreneurship is increasingly recognized both in research and practice as a form of entrepreneurship that is inherently hybrid as it combines a social-welfare logic with a commercial logic at its core. Collective dynamics, whether they point at an networked individual or a team, appear particularly salient both in the discourse on social entrepreneurship and in its practice. These would constitute a distinguishing feature of social entrepreneurship, which this dissertation examines through a set of four related research papers. First, social entrepreneurship as generically collective is taken as a starting point to review the literature. In particular, it identifies how the social network concept is used in relation to social entrepreneurship and develops research proposals aiming to explain social entrepreneurship emergence through this lens. Considering the entrepreneurial team as a crystallized social network that allows for bridging distinct logics constitutes one of these proposals, which is further explored in the second paper. Grounded in institutional theory, it develops a processual model describing how hybridity emerges and sustains throughout the entrepreneurial process and suggests that the entrepreneurial team may be a carrier of hybridity. The empirical part of the dissertation examines particular moments of this process. The third paper questions the collective dimension by seeking individuals’ meanings of entrepreneuring in team in the context of social entrepreneurship. Located a bit further in time in the entrepreneurial process, the fourth paper looks at organizational tensions in social entrepreneurial teams and nascent social enterprises and seeks to portray the manifestations of hybridity. Overall, this dissertation contributes to institutional theory by exploring the emergence of hybrid organizations; to team entrepreneurship literature by unravelling its antecedents and by explaining tensions in a context of institutional complexity; and to knowledge on social entrepreneurship by examining its collective dynamics at the early stages of the process. [less ▲]

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See detailMonitoring water and pollutant leaching at an industrial site using geophysics and a vadose zone monitoring system.
Fernandez de Vera, Natalia ULg

Doctoral thesis (2016)

The development of protection and remediation plans for contaminated soil and groundwater require a detailed understanding of water flow dynamics and contaminant distribution in the subsurface. However ... [more ▼]

The development of protection and remediation plans for contaminated soil and groundwater require a detailed understanding of water flow dynamics and contaminant distribution in the subsurface. However, the retrieval of such information across the vadose zone is challenging, as most field technologies have limited accessibility beyond the first meters of subsoil and industrial environments pose additional technical difficulties for installation. The research presented here aims to provide effective in situ characterization tools that are capable of providing information about water flow dynamics, contaminant distribution and chemistry across the vadose zone of industrial contaminated sites. The Vadose Zone Monitoring System (VMS) was selected in conjunction with geophysical methods (Electrical Resistivity Tomography), given their adaptability for installation in polluted industrial sites. The VMS allows retrieval of in situ continuous hydraulic and chemical information of infiltrated water at different depths of the vadose zone through customized sensors installed in a slanted borehole. The spatial resolution of the subsurface is improved with geophysical methods, which are used to characterize structural heterogeneities in the subsurface and the spatial distribution of solutes therein. The setup containing both the VMS and a geophysical system was installed at a former industrial contaminated site in the west of Belgium. Soil and groundwater at the study site are contaminated with heavy metals, Polycyclic Aromatic Hydrocarbons (PAH) and inorganic contaminants, among others. Upon installation, the site was monitored under natural recharge conditions. Results from water content sensors installed in the VMS reveal quick rises in water content as a response to rainfall events to depths reaching 3.65m. From such water fluctuations, macropore, micropore, matrix and preferential flow mechanisms are identified. At greater depths, slower flow dynamics and matrix mechanisms are dominant. Results from sampled waters across the vadose zone reveal the existence of two predominant chemical facies at different depths, which are related with water infiltration flow mechanisms. Ni is identified as the main contaminant that is leaching across the vadose zone. Subsequent to such initial monitoring period, a saline tracer test was infiltrated on site and monitored via surface, cross-borehole ERT methods and the VMS to simulate the transport of a contaminant across the vadose zone. Results from a short term monitoring period (5 days) reveal the formation of a plume in the first meter of the subsurface. Slow vertical flow through matrix is found to be dominant. Measurements carried out 105 days after tracer infiltration vertical transport of the tracer towards depths that reached 4m. Results obtained from the VMS indicate that the tracer has reached such depths through the activation of matrix and fracture flow mechanisms following frequent rainfall episodes. The implementation of the setup has provided detailed information about water flow dynamics and chemistry across the vadose zone, as well as the spatial characterization of structures and tracer distribution in the subsurface. From such outcome, it can be concluded that this setup could be used to improve site conceptual models which are essential for developing risk assessments and remediation plans. [less ▲]

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See detailL'injonction de payer
Berthe, Aude ULg

Doctoral thesis (2016)

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See detailMethods and models for brain connectivity assessment across levels of consciousness
Amico, Enrico ULg

Doctoral thesis (2016)

The human brain is one of the most complex and fascinating systems in nature. In the last decades, two events have boosted the investigation of its functional and structural properties. Firstly, the ... [more ▼]

The human brain is one of the most complex and fascinating systems in nature. In the last decades, two events have boosted the investigation of its functional and structural properties. Firstly, the emergence of novel noninvasive neuroimaging modalities, which helped improving the spatial and temporal resolution of the data collected from in vivo human brains. Secondly, the development of advanced mathematical tools in network science and graph theory, which has recently translated into modeling the human brain as a network, giving rise to the area of research so called Brain Connectivity or Connectomics. In brain network models, nodes correspond to gray-matter regions (based on functional or structural, atlas-based parcellations that constitute a partition), while links or edges correspond either to structural connections as modeled based on white matter fiber-tracts or to the functional coupling between brain regions by computing statistical dependencies between measured brain activity from different nodes. Indeed, the network approach for studying the brain has several advantages: 1) it eases the study of collective behaviors and interactions between regions; 2) allows to map and study quantitative properties of its anatomical pathways; 3) gives measures to quantify integration and segregation of information processes in the brain, and the flow (i.e. the interacting dynamics) between different cortical and sub-cortical regions. The main contribution of my PhD work was indeed to develop and implement new models and methods for brain connectivity assessment in the human brain, having as primary application the analysis of neuroimaging data coming from subjects at different levels of consciousness. I have here applied these methods to investigate changes in levels of consciousness, from normal wakefulness (healthy human brains) or drug-induced unconsciousness (i.e. anesthesia) to pathological (i.e. patients with disorders of consciousness). [less ▲]

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See detailProfessionalization of Human Resource Management in Social Enterprises
Moreau, Charlotte ULg

Doctoral thesis (2016)

Social enterprises put the human being at the heart of their functioning. But managing human beings, and consequently managing human resources, remains poorly developed and studied in social enterprises ... [more ▼]

Social enterprises put the human being at the heart of their functioning. But managing human beings, and consequently managing human resources, remains poorly developed and studied in social enterprises. However, the social enterprise sector is currently undergoing important changes: increased complexity of legal and institutional frameworks; focus on impact evaluation; transformation of public funding schemes; increased competition, etc. Those evolutions question the functioning of social enterprises and strongly impact their human resource management (HRM) practices. A movement towards professionalization of social enterprises is observed. In this doctoral thesis, we focus on the topic of HRM professionalization in social enterprises. First, we clarified our understanding of the black box of professionalization. We developed a conceptual model composed of three dimensions, the HR tools, the HR function and the HR philosophy, which together allowed apprehending HRM professionalization. Then, the data collection was achieved through a methodology mixing quantitative and qualitative approaches. Indeed, a large quantitative survey was conducted by sending a questionnaire to the Belgian French-speaking social enterprises working with at least ten workers. In parallel, in-depth case studies were performed in four voluntary very different social enterprises, as the objective was to observe the diversity of the HR practices. The results of those mixed-methodologies offer a wealth of learning opportunities and allow for a better apprehension of HRM and its evolution in social enterprises. An important diversity in the HR practices is observed. A certain level of formalization has to be highlighted but the real stakes lay elsewhere. The deeper issues in terms of HRM professionalization occur around the HR function, i.e. the roles of the HR actors, but above all around the philosophy underlying the HR evolutions. Indeed, social enterprises seem constructed, even implicitly, around a critical choice that impacts the whole organization and its functioning. That critical choice can be conceived as the internal concretization of the organization’s larger mission and is thus specific to each social enterprise. The paths of HRM professionalization and its different dimensions are strongly influenced by these critical choices. In social enterprises, the critical choices act as a filter toward the potential external pressures. Furthermore, critical choices are the results of an evolving compromise between different logics. If new logics arise, the critical choice is challenged, leading to strong questionings of HR issues among others. Critical choices are subject to an important legitimization and power stakes between the actors. Finally, these different elements let us think that the classic perspectives on HRM (universalistic, contingency and configurational) are hardly appropriate here. Consequently, we offer a new approach, a “processual” perspective to study the paths of HRM professionalization by considering the contexts surrounding the social enterprise, their internal characteristics, the power stakes around those questions and the evolution of all these elements through time. The contributions of this work include the “processual” approach, the conceptual model or the analysis of a poorly studied phenomenon. [less ▲]

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See detailCaractérisation multiscalaire de contaminations en éléments traces dans les sols : distribution spatiale et verticale, évaluation du transfert sol-plante-vers de terre et gestion potentielle par amendements organiques
Liénard, Amandine ULg

Doctoral thesis (2016)

Human economic and technological development has a negative impact on the environment. The soil is not spared from this growing threat through its role in the environmental interface. Once degraded as a ... [more ▼]

Human economic and technological development has a negative impact on the environment. The soil is not spared from this growing threat through its role in the environmental interface. Once degraded as a result of contamination, it can no longer fulfill its ecosystem functions such as the protection of ecosystems, food production or preservation of the quality of surface water and groundwater. The studies presented in the thesis are on soil contaminated by atmospheric fallouts enriched by trace elements. This type of contamination increases the natural levels of contaminants in soils and particularly in surface horizons to exceed the maximum levels set by legislation. The first axe of research concerns the assessment of contamination at a landscape scale around a former zinc-lead ore-treatment plant. The spatial distribution of cadmium, lead and zinc in the topsoil (0-20 cm) was characterized using 247 samples taken in crop, grassland and forest on three major types of loam soils representative of the study area Sclaigneaux (Wallonia, Belgium). The distribution of contaminants is explained by the distance to the source of contamination, direction of dominant winds, land use and soil type. Subsequently, 22 soil profiles were sampled within the study area to estimate the vertical transfer of contaminants. Based on various indexes of contamination, no migration along the profiles has been demonstrated. Only some more clay horizons presented contaminant levels that increased relative to their upper horizons. The second approach studied the soil-plant transfer and soil-plant-worm transfer of contaminants. First, a field study of the quality of grains of barley (Hordeum vulgare L.) harvested in the study area Sclaigneaux was performed. It appears that the concentration of cadmium in the grain meets quality standards for placing the cereals on the market. However, 78% and 94% of zinc and cadmium, respectively, concentrations measured in grains exceed the expected levels of a non-impacted environment by human activity. Secondly, a study on microcosms was conducted with soils of agricultural parcels around Sclaigneaux on which two crops (faba bean, Vicia faba L. and corn, Zea mays L.) were grown and where earthworms (Eisenia fetida (Savigny)) were introduced. The life traits of E. fetida such as mortality and adult weight were not affected by the levels of contaminants unlike the presence of plants which limit their reproduction (weight and number of cocoons). Moreover, the presence of E. fetida in microcosms influenced the mobility and bioavailability of contaminants. The third approach deals with metal contaminations in vegetable gardens and their management using organic amendments. This method of stabilization aims to decrease the labile fraction of soil contaminants and further reduce their transfer to plants. To do so, two vegetables (spinach, Spinacia oleracea L. and lettuce, Lactuca sativa L.) were grown on contaminated garden soils enriched in various amendments sold in garden centers. The major finding of this study is that management by amendments does not allow a systematic decrease in the soluble fraction contaminants. This is mainly due to the direct intake of rapidly mobilized trace elements produced by the addition of some of the studied amendments. [less ▲]

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See detailDynamics of ligands on gold surface to obtain Janus nanoclusters: A theoretical and experimental investigation
Lugo Preciado, Jesús Gustavo ULg

Doctoral thesis (2016)

We performed a joint computational – experimental investigation of the dynamics of ligand exchange on gold nanoclusters (GNC) surface with the aim to understand how to control the structural and optical ... [more ▼]

We performed a joint computational – experimental investigation of the dynamics of ligand exchange on gold nanoclusters (GNC) surface with the aim to understand how to control the structural and optical properties of GNC through the design of their ligand shell. Our computational studies were carried out in the framework of the Kohn – Sham implementation of density functional theory in quantum chemistry. We analyzed the main features of UV – Vis spectra computed at the TD – DFT / CAM – B3LYP level for the Au13, Au25, and Au28 metallic cores protected by thiolate, chloride, and phosphine ligands. Our results show that it is possible to tune the energy of the lowest absorption band of gold clusters by ligand shell engineering in order to control the charge redistribution between ligand shell and metallic core. In parallel we synthesized a set of Au25(ATP)x(TP)18 – x clusters with different ATP/TP ratios using an adapted Demessence protocol by combining 4ATP (4 – aminothiophenol) and TP (thiophenol) ligands. ESI – MS measurements evidence that for these mixed ligand shells the Au25 nuclearity is preserved. However, the addition of the DDT (1 – dodecanethiol) ligand in the mixture leads to nanoparticle formation. FT – IR spectroscopy confirms the absorption of two different ligands on the gold surface and SAXS shows that we have a good correlation between the distance between two clusters and the length of the ligand protecting them. Furthermore, we collaborated with the Institut Charles Gerhardt in the Université de Montpellier, France whose experimental results show that several n – heterocyclic carbenes (NHC) bearing different groups on the N atoms exhibit similar reactivity when protecting a gold nanosurface. The formation of the bis(NHC) AuI gold complexes is evidenced by 13C NMR. In order to complement and interpret the experimental results, we carried out a computational study of the adsorption of a single NHC on Au38 which acts as a model for the gold surface, as well as of the fully NHC ligated Au38 cluster. The joint experimental – theoretical study, in particular the comparison between computed and 13C NMR spectra allows proposing a possible mechanism explaining the formation of [NHC – Au – NHC]+ complexes and the erosion experienced by the nanoparticle. Finally, we carried out a comparison of the mode of binding and the structural and optical properties of the fully ligated PH3 and NHC GNC with metallic cores of different nuclearities. Our computations show that the Au – P bond is weaker than the Au – NHC one. Additionally, our study confirms that the ligand – to – metal charge transfer is an important parameter for understanding the electronic transitions and the UV – Vis spectra in these clusters. Our computations on the PH3 – Au38 set of complexes show that there is a site selectivity for the reactivity for the PH3 interacting on the Au38 surface which allows predicting where the PH3 is likely to be adsorbed. This selectivity is not observed in the case of the binding of a single NHC ligand on the surface of the Au38 cluster. [less ▲]

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See detailETUDE FONCTIONNELLE DES FACTEURS D’ÉPISSAGE SR D’ARABIDOPSIS THALIANA
Stankovic, Nancy ULg

Doctoral thesis (2016)

Dans ce travail, nous avons montré que la protéine RSZ22, est une protéine hautement dynamique. Cette protéine fait partie de la sous-famille des protéines RSZ d’Arabidopsis et est l’homologue de la ... [more ▼]

Dans ce travail, nous avons montré que la protéine RSZ22, est une protéine hautement dynamique. Cette protéine fait partie de la sous-famille des protéines RSZ d’Arabidopsis et est l’homologue de la protéine SRSF7 humaine. Elle possède un domaine RRM, un domaine RS et entre les deux un domaine de liaison au RNA Zn-knuckle de type CCHC. L’utilisation des approches de FRAP (Fluorescence Recovery After Photobleaching) et de FLIP (Fluorescence Loss In Photobleaching) ont permis d’étudier la dynamique de cette protéine mais aussi sa capacité de navette entre le noyau et le cytoplasme comme son homologue humain SRSF7. Ces études ont été réalisées avec RSZ22 fusionnée à la GFP et surexprimée transitoirement dans des cellules foliaires mais aussi en transformation stable chez Arabidopsis (Rausin et al., 2010; Tillemans et al., 2006). Dans cette étude, nous avons montré que RSZ22, comme les protéines de la famille SR, est une protéine navette. Par analyses de FLIP-shuttling nous avons pu établir des cinétiques d'exportation et confirmer que les protéines SR végétales utilisent le récepteur CRM1/XPO1 comme voie d’exportation. Sa mobilité dépend du niveau de phosphorylation et de la concentration en ATP de la cellule. La complémentarité des techniques de surexpression en transformation transitoire et de l’expression stable ayant été démontrée (Rausin et al., 2010), nous nous y sommes référés pour notre étude de dynamique des protéines nucléaires. Nous avons également cherché à évaluer les rôles des domaines d’accrochage au RNA de RSZ22 dans sa localisation et sa dynamique. Par mutagenèse dirigée, nous avons modifié les acides aminés conservés connus pour jouer un rôle dans les interactions avec le RNA (Clery et al., 2008; Hargous et al., 2006; Lunde et al., 2007; Maris et al., 2005; Phelan et al., 2012). Nos résultats montrent que les domaines Zn-knuckle et RRM fonctionnels ne sont pas nécessaires à la localisation nucléaire de la protéine RSZ22, ni à sa localisation en speckles. La dynamique nucléocytoplasmique de la protéine RSZ22 n’est pas altérée par la mutation des motifs Zn-knuckle et RNP1. Cependant, les protéines mutées de RSZ22 répondent différemment aux traitements par la LMB. En effet, celles-ci ne sont plus « retenues » dans le noyau après un tel traitement et continuent d’être exportées vers le cytoplasme. Sachant que la LMB est un inhibiteur spécifique de la voie CRM1/XPO1, ce dernier récepteur est impliqué dans l’exportation des protéines SR en interaction avec le RNA (Williams et al., 2008). Dans la suite des recherches réalisées au sein du laboratoire, nous avons étudié la dynamique nucléo-cytoplasmique des protéines SR, en étudiant la sous-famille SRSF1-like. Chez Arabidopsis thaliana, cette famille se compose des protéines SR34, SR34a, SR34b et SR30 et possède deux domaines RRM et un domaine RS. Comme RSZ22, SR34 et SR34a font la navette entre le noyau et le cytoplasme. Nous formulons ainsi l’hypothèse que comme son homologue humain SRSF1, SR34 pourrait être impliquée dans l’exportation du mRNA vers le cytoplasme. Nous avons analysé les rôles des différents domaines de SR34 par mutagénèse dirigée. Nous avons montré que le domaine RS de la protéine SR34 est nécessaire pour la localisation nucléaire et la stabilité de la protéine. Les motifs de liaison au RNA sont impliqués dans l’exportation de SR34 par la voie CRM1/XPO1. Par la technique du double hybride en levure, une interaction entre SR34 et SR45 a pu être mise en évidence et confirmée par FLIM-FRET (Fluorescence-Lifetime Imaging Microscopy - Fluorescence Resonance Energy Transfert). L’analyse des interactions entre SR45 et les protéines SR34 mutantes montre l’importance des différents domaines de la protéine dans les interactions protéine-protéine. [less ▲]

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See detailETUDE SUR LA REALISATION ET LES COMPLICATIONS DE LA CESARIENNE DANS LA RACE BLANC BLEU BELGE
Djebala, Salem ULg

Master of advanced studies dissertation (2016)

La césarienne est une chirurgie importante en Wallonie. Pour faire le point sur cette intervention chirurgicale et les complications post-opératoires qui en découlent ; deux enquêtes ont été adressées aux ... [more ▼]

La césarienne est une chirurgie importante en Wallonie. Pour faire le point sur cette intervention chirurgicale et les complications post-opératoires qui en découlent ; deux enquêtes ont été adressées aux vétérinaires ruraux et aux éleveurs de Blanc-bleu Belge exerçant dans cette région. Ces deux enquêtes traitent différents points, notamment : la détection et la surveillance des vêlages, la préparation de la césarienne (box à césarienne, tonte ou rasage, asepsie), les différentes techniques, les matériaux et les médicaments utilisés pour réaliser une césarienne ainsi que les soins et les complications postopératoires observées. Les résultats de ces deux enquêtes ont permis de constater la diversité des pratiques, mais également, le fait qu’un certain nombre d’entre elles s’écartent des recommandations académiques ou bibliographiques habituelles. Ces deux enquêtes ont permis aussi de mettre en relation les différentes pratiques des éleveurs et des vétérinaires avec les complications post-opératoires observées. A l’issus de ces enquêtes, des recommandations ont été formulées afin d’exclure les mauvaises pratiques habituelles des vétérinaires et des éleveurs et de réduire le pourcentage des complications postopératoires recensées sur le terrain. Ces enquêtes nous ont permis aussi de pointer du doigt certains points obscurs qui feront l’objet de nouvelles perspectives de recherche. [less ▲]

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See detailCaractérisation biochimique et structurale des tagatose-1,6-bisphosphate aldolases de classe I d’origine procaryotique
Freichels, Régine ULg

Doctoral thesis (2016)

La réaction d’addition catalysée par la D-tagatose-1,6-bisphosphate aldolase (TBPA) de classe I n’est pas spécifique. A partir du dihydroxyacétone phosphate et du D-glycéraldéhyde-3-phosphate, la TBPA ... [more ▼]

La réaction d’addition catalysée par la D-tagatose-1,6-bisphosphate aldolase (TBPA) de classe I n’est pas spécifique. A partir du dihydroxyacétone phosphate et du D-glycéraldéhyde-3-phosphate, la TBPA génère quatre D-cétohexoses-1,6-bisphosphate qui diffèrent au niveau des carbones 3 et 4 : D-tagatose-1,6-bisphosphate, D-fructose-1,6-bisphosphate, D-psicose-1,6-bisphosphate et D-sorbose-1,6-bisphosphate. Dans le cadre de ce travail, nous contribuons à la compréhension du contrôle stéréochimique de cette enzyme en identifiant des acides aminés impliqués dans sa spécificité. Pour ce faire, une analyse in silico a été réalisée afin de sélectionner des TBPA présentant des particularités dans le site actif. Des alignements de séquences montrent que la lysine à la position 125, décrite comme importante pour la catalyse, est remplacée par une arginine dans une seule TBPA : celle de Streptococcus porcinus. Les paramètres cinétiques révèlent que cette arginine entraine un changement de spécificité en faveur du D-tagatose-1,6-bisphosphate alors que la lysine correspondante est importante pour une spécificité élargie. Cependant, l’arginine diminue fortement l’activité de clivage et de formation des D-cétohexoses-1,6-bisphosphate. La détermination de la structure par cristallographie des rayons-X aide à comprendre le rôle de l’arginine dans la TBPA de S. porcinus. Finalement, des études HPLC révèlent que toutes les TBPA synthétisent principalement du D-tagatose-1,6-bisphosphate et du D-fructose-1,6-bisphosphate. [less ▲]

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See detailBrain connectivity and sensory stimulation in disorders of consciousness
Heine, Lizette ULg

Doctoral thesis (2016)

This thesis explores brain connectivity and sensory stimulation in patients with disorders of consciousness (DOC). These are serious conditions where massive brain damage can lead to a dissociation ... [more ▼]

This thesis explores brain connectivity and sensory stimulation in patients with disorders of consciousness (DOC). These are serious conditions where massive brain damage can lead to a dissociation between arousal and awareness (e.g., UWS and MCS). Part I explores brain connectivity. We highlight that brain function and structure are intimately related to each other, and to consciousness. The decrease in brain function can be used to distinguish between the clinically indicated states of consciousness. Part II evaluates passive sensory stimulations. Preferred stimuli may have the power to momentarily enhance brain function, and behavioral responses. [less ▲]

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See detailLes conséquences civiles des polices administratives sur la vente immobilière. Etude comparée des droits wallon, flamand et bruxellois
Onclin, François ULg

Doctoral thesis (2016)

On observe une influence grandissante des polices administratives sur le droit des contrats. La police administrative désigne l'ensemble des pouvoirs qui sont accordés, par ou en vertu d'une disposition ... [more ▼]

On observe une influence grandissante des polices administratives sur le droit des contrats. La police administrative désigne l'ensemble des pouvoirs qui sont accordés, par ou en vertu d'une disposition législative, aux autorités administratives et qui permettent de restreindre les droits et libertés des individus en vue d'assurer le maintien de l'ordre public. A côté de la police administrative générale qui tend à assurer le maintien de la sécurité, de la salubrité et de la tranquillité publiques, de nombreuses polices administratives spéciales se sont développées. Ces dernières visent à prévenir des troubles spécifiques, dont l'objet est défini par chaque législation particulière. Lors de la mise en œuvre de sa compétence, le législateur de police recourt à différents procédés. Il en résulte que de nombreuses contraintes de police encerclent les opérations contractuelles qui portent sur des biens immeubles. La recherche entreprise a toutefois limité son champ d’étude à la vente immobilière étant donné qu’il s’agit de l’acte de droit civil le plus fréquent et le plus souvent encadré par les polices administratives des biens. La législation de police renforce parfois la violation des exigences qu’elle impose d’une sanction administrative ou pénale. L’exercice se complique lorsqu’il s’agit d’apprécier les conséquences civiles des polices administratives. Dans ce cas, il convient à la fois de se référer à la théorie générale des obligations et à l’éventuelle sanction civile qui est aménagée par la législation de police. Tel est précisément l’objet de cette thèse, à savoir l’étude des conséquences, sur le plan civil, des polices administratives sur la vente immobilière. La thèse se structure en deux parties. La première a examiné la situation dans laquelle les polices administratives influencent la formation de la vente. La seconde avait, quant à elle, pour objet d’apprécier la mesure dans laquelle ces mêmes polices ont un impact sur les effets de la vente. Le système de répartition des compétences mis en place au sein du fédéralisme belge impose une recherche comparée. Celle-ci est entreprise en droit interne. De nombreuses polices administratives ont été, pour d’importantes parties, régionalisées. Elles ressortissent dès lors à la compétence du législateur régional. Pour cette raison, la recherche a été étendue aux droits wallon, flamand et bruxellois. Le droit des obligations et des contrats demeure, sous réserve de certaines exceptions, de la compétence de l’autorité fédérale. Lorsque la sanction civile est étudiée, il en résulte une tension entre, d’une part, la compétence du législateur fédéral et, d’autre part, celle du législateur de police. La rigidité de cette division des compétences engendre des difficultés. [less ▲]

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See detailL'ENSEIGNEMENT DU FRANÇAIS AUX ANGLOPHONES AU CAMEROUN : ANALYSE ET PROPOSITIONS DIDACTIQUES
Mouto Betoko, Christiane ULg

Doctoral thesis (2016)

Au Cameroun, l’école est la garante de la politique du bilinguisme officiel qui vise à faire de tous les citoyens camerounais des individus parfaitement bilingues, afin de garantir leur intégration sur ... [more ▼]

Au Cameroun, l’école est la garante de la politique du bilinguisme officiel qui vise à faire de tous les citoyens camerounais des individus parfaitement bilingues, afin de garantir leur intégration sur l’ensemble du territoire national. Les élèves anglophones apprennent donc le français, leur deuxième langue officielle (LO2), comme toutes les autres disciplines, tout au long de leur cursus secondaire. En classes terminales, l’un des objectifs prioritaires de l’enseignement de la LO2 (French) est de préparer les élèves à intégrer les milieux universitaires et/ou socioprofessionnels majoritairement implantés en zone francophone. Néanmoins, dans ce contexte, l’atteinte des objectifs scolaires du bilinguisme constitue une problématique imputable à de nombreuses inadéquations inhérentes au sous-système éducatif anglophone. C’est dans cette optique que nous nous sommes demandé comment allier « objectifs scolaires du bilinguisme » et « méthodologie de l’enseignement du French» pour une préparation effective de notre public cible à son intégration dans son milieu de vie au sortir du secondaire. Ainsi, nous avons inscrit cette étude dans le champ épistémologique de la didactique du français langue étrangère, domaine disciplinaire qui fait de la connaissance des publics le point de départ de tout projet de formation en langues étrangères. Ceci dit, nous défendons la thèse selon laquelle la prise en compte des besoins réels des principaux acteurs devrait constituer l’étape préalable à la mise au point des projets de réforme tels la réforme du système éducatif et par ricochet, des programmes de formation que connaît actuellement l’éducation au Cameroun. Ayant constaté que l’environnement sociolinguistique où se déroulent l’enseignement et l’apprentissage du French n’est pas sans conséquence directe sur la mise en application du bilinguisme scolaire, nous avons jugé nécessaire de comprendre les politiques linguistique et éducative du milieu d’étude. Ainsi, dans la première partie de ce travail, il convenait de s’interroger sur le mode d’emploi réel des langues officielles, particulièrement en ce qui concerne l’usage de la langue française dans la société camerounaise ; de comprendre la problématique de la formation bilingue au Cameroun ; de questionner la place des langues maternelles à l’école ; d’analyser les failles du sous-système éducatif anglophone en matière d’enseignements des langues officielles ; et enfin, de mener une réflexion didactique sur les programmes de français II. Dans la deuxième partie de ce travail, nous avons mis en exergue l’importance de la prise en compte des caractéristiques des principaux acteurs de la salle de classe dans l’élaboration des programmes de formation. Les profils de ces acteurs étant absents des directives institutionnelles, nous les avons questionnés pour mettre leurs caractéristiques au grand jour. Pour ce faire, nous avons mené une enquête de terrain dans les deux régions qui constituent la zone anglophone (Nord-Ouest et Sud-Ouest) et, dans une région de la zone francophone (Centre). La récolte des données s’est faite par le biais de deux questionnaires (un pour les enseignants et un pour les élèves en classes terminales) et d’une grille d’observation des pratiques de classe. La méthode utilisée est l’analyse quantitative et descriptive des données statistiques. À travers la discussion des résultats obtenus sur la terrain d’enquête, nous avons validé l’hypothèse générale émise au départ, stipulant qu’il y a actuellement une inadéquation entre les objectifs scolaires du bilinguisme et la méthodologie mise en œuvre pour les atteindre en classes terminales du sous-système éducatif anglophone. À travers cette démonstration, nous avons tout simplement touché du doigt la réalité selon laquelle l’atteinte des objectifs visés dans le cadre du bilinguisme ne peut se faire sans avoir établie, au préalable, les besoins réels des principaux acteurs de la salle de classe. [less ▲]

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See detailNietzsche & la neurologie
JEDIDI, Haroun ULg

Master of advanced studies dissertation (2016)

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See detail« Le courtage associatif en développement et l’émergence de nouvelles élites rurales dans le Sud-Est marocain. Le cas de la région Drâa-Tafilalet »
Benidir, Mohammed ULg

Doctoral thesis (2016)

Cette recherche appréhende le renouvellement des élites sur fond de courtage associatif en développement dans les arènes locales de la région de Drâa-Tafilalet dans le Sud-Est du Maroc. Sur la base d’une ... [more ▼]

Cette recherche appréhende le renouvellement des élites sur fond de courtage associatif en développement dans les arènes locales de la région de Drâa-Tafilalet dans le Sud-Est du Maroc. Sur la base d’une enquête ethnographique, nous tenterons de comprendre les processus individuels et collectifs du courtage associatif dans le domaine du développement local. Dans cette région présaharienne, le courtage associatif s’avère être un phénomène composite et imbriqué avec des structures tribales, notabiliaires, associatives, bureaucratiques et politiques. Par ailleurs, le courtage associatif prend deux formes principales : la première est liée à la rétribution matérielle qui favorise la mobilité socioprofessionnelle grâce à l’intermédiation pour la mise en œuvre projets de développement. La seconde est relative à la rétribution symbolique et politique, qui permet aux courtiers associatifs de négocier des positions de leadership en vue d’accéder au rang d’élite. Les profils sociologiques et politiques des courtiers associatifs attestent de l’émergence d’un nouveau groupe élitaire homogène. Celui-ci adopte une stratégie de redéploiement qui emprunte de nouvelles voies d’intermédiation lors de la conduite de projets de développement. L’étude révèle enfin l’existence de conflits à en juger par l’affrontement entre de nouvelles élites rurales et les élites politiques en place lors de la gestion des affaires publiques villageoises. Il s’ensuit de ce qui précède une recomposition des relations de pouvoir dont notamment le renforcement des capacités de l’État en matière de cooptation et de régulation des arènes compétitives entre courtiers. [less ▲]

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See detailPertes et Reconstructions Identitaires des Foyers Post-Divorce
Bullens, Quentin ULg

Doctoral thesis (2016)

La présente étude s’intéresse au parcours des foyers post-divorce via deux objectifs. Premièrement, nous voulons mettre en avant les éléments organisateurs permettant à ces foyers de passer d’un état à un ... [more ▼]

La présente étude s’intéresse au parcours des foyers post-divorce via deux objectifs. Premièrement, nous voulons mettre en avant les éléments organisateurs permettant à ces foyers de passer d’un état à un autre. Pour ce faire, nous recourons à la méthode par théorisation ancrée, bien qu’en nous en écartant partiellement. Deuxièmement, nous cherchons à savoir quels sont les champs lexicaux qui peuvent être extraits des transcriptions d’entretiens avec ces foyers. Pour ce second objectif, nous recourons à la méthode Alceste, via le logiciel Iramuteq. Celui-ci nous permet un croisement des données d’entretiens avec des métadonnées issues notamment du FACES-III et du Jeu du Pique-Nique. Tous ces éléments sont discutés au regard des apports de la littérature scientifique. Mais aussi, au regard de la clinique du deuil, à laquelle il est fait appel pour éclairer ces parcours. En outre, nous contextualisons les notions de famille, mariage et divorce dans une perspective historique prenant ses bases au Moyen Âge. [less ▲]

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See detailRôle du climat et de la compétition interspécifique dans la limitation de l'aire d'invasion d'Ambrosia artemisiifolia L. en Europe de l'Ouest
Ortmans, William ULg

Doctoral thesis (2016)

The invasion process is classically described from a temporal point of view, where a species overcomes a defined number of barriers. First, a species has to get through the geographical barrier, i.e., be ... [more ▼]

The invasion process is classically described from a temporal point of view, where a species overcomes a defined number of barriers. First, a species has to get through the geographical barrier, i.e., be introduced in the new area. Once introduced, the species has to survive new environmental conditions and reproduce successfully. When the environmental barrier is overcome, i.e. when the species is able to reproduce and its populations are self-sufficient, it is considered as naturalized. To finally be considered as invasive, the species has to overcome the dispersal barrier and spread across landscapes. Within a given continent, a species could have overcome a variable number of barriers depending on the considered area. At a given moment, depending on the geographical area, one can observe non-naturalized populations, naturalized populations that are not invasive, and invasive populations. This geographical variation may be the result of an environmental variation across the continent. The common ragweed (Ambrosia artemisiifolia L.) invasion in Western Europe is a good opportunity to study this aspect of invasion biology. The invasion history and the species distribution are well documented, and highlight a geographical variation of the invasion dynamics. This is particularly clear in Western Europe, where there is a contrast between the highly invaded zone of the Rhône valley in France, and more northern areas such as the North of France, Belgium, and the Netherlands. In this work, we tested the hypothesis that the current invasion area is limited northwards, because of an unfavorable local climate or a too strong interspecific competition. In order to answer this general objective, four different questions were asked: 1) Is the climate and/or the interspecific competition causing a variation in plant performances across Western Europe?; 2) In an agricultural context north to the current invaded range, is the local climate allowing the establishment and the reproduction of newly introduced populations?; 3) What is the role of seed morphological variability in the invasion of areas with rigorous climatic conditions?; and 4) What is the role of the priority effect in the species establishment within a ruderal community? No clear limit to the colonization of areas beyond the current invaded range was found in this study. The local climate and the interspecific competition did not appear to limit the naturalization or spread of the species north to the current invaded range, be it in agricultural or ruderal situations. Results showed that once introduced in an agricultural habitat outside the current invaded range, the species was able to establish self-sustaining populations. On average, each plant produced a number of descendants equal to 273 ± 18.4 (mean ± standard error). In ruderal habitats, populations already exist in Belgium and in Southern Netherlands, and are able to produce a high quantity of seeds: on average, the measured plants carried 222 ± 32.0 seeds. The measured plant performances were similar to those measured within the invaded area. The findings of this work are consistent with those of other authors that questioned the “non-naturalized” species status in Belgium, and illustrate how temporally dynamic invasions are. The results showed the importance of the timing in the colonization of disturbed habitats. When the species started its development a few weeks before the rest of the community, its performance gain was higher than that of other ruderal Asteraceae species: its above ground biomass was 30.5 ± 1.94 times higher, and the number of flower heads 570 ± 160 times more important. The high variability of the species observed all along this work is probably playing an important role in the invasion success. The high morphological variability of the seeds seems to widen the range of environmental conditions the species is able to colonize. This study suggests a great invasion potential north to the current invaded area in Western Europe. In this uncertain situation, it appears critical to create an early detection system of the species in Belgium. Early detection may allow the eradication of the species before the invasion becomes as problematic as in France. Awareness campaigns should be encouraged in Belgium in order to avoid that new occurrences of the species remain unnoticed. [less ▲]

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See detailContribution to the study of the mineral hypothesis in relation to the Kashin-Beck disease in Tibet Autonomous Region
DERMIENCE, Michael ULg

Doctoral thesis (2016)

A little known disease called Kashin-Beck disease (KBD) plagues the poor and rural populations in the Tibet Autonomous Region (T.A.R.) and in other provinces of the People’s Republic of China. It is an ... [more ▼]

A little known disease called Kashin-Beck disease (KBD) plagues the poor and rural populations in the Tibet Autonomous Region (T.A.R.) and in other provinces of the People’s Republic of China. It is an endemic and chronic osteochondropathy affecting long bones and joints, sometimes as soon as of the early childhood. Although the etiology of this disease is not clearly established, little doubt remains as to the implication of multiple environmental factors. Intoxication by mycotoxins in cereals and by organic acids in water, deficiencies in selenium and iodine, are all factors having a place in the multifactorial etiology hypothesized. In T.A.R., diet, notably, differentiates the rural community, affected by KBD, from the other communities (nomads and city-dwellers), who remain unaffected. Because more than one chemical element is essential to a healthy bone metabolism, and because there is scarce data, if not any, on the topic, this thesis had to primary objective to investigate the mineral and trace element dietary status of young Tibetan children living in areas endemic for KBD. The first logical action step led us to determine which elements are involved in bone and joints metabolism through an exhaustive review of the scientific literature. Thirty elements were highlighted, and a dozen was deemed relevant in this context. An exploratory study on the Tibetan food composition concluded on a high risk of introducing important bias by using the existing food composition tables for nutritional assessment in T.A.R. Being inescapable tools, a specific food composition table was elaborated for our area of investigation with the close collaboration of the China National Center for Food Safety Risk Assessment (CFSA). During a scientific internship of 7 month in the CFSA, 19 chemical elements were analyzed in not less than 1119 samples of sixteen traditional foods and beverages of rural T.A.R. In order to assess the nutritional status of the children, a cross-sectional study was implemented. 250 preschool children aged 3 to 5 years old from three rural counties around Lhasa were enrolled. They were interviewed twice, at six month of interval, via the 24-hour recall method. The results suggest several imbalances in their dietary mineral intakes compared to the Chinese recommendations. Sodium and manganese intakes are too high, while they are too low for potassium, calcium, zinc, copper and selenium. The Tibetan diet is rich in fiber and in phytic acid, which are susceptible to decrease the bioavailability and to aggravate the deficiencies of the later elements. For this reason, we conducted an animal experimentation on a rat model to assess the apparent digestibility, the fecal excretion and the urinary excretion of minerals and trace elements in the traditional Tibetan dish called tsampa pag. This traditional dish consisting of roasted barley flour mixed with yak butter tea is the mainstay of the Tibetan diet. The results of this experiment suggest low bone mineral density, a possible secondary copper deficiency, and a possible manganese excess in rats that consumed tsampa pag. In view of the results presented, it would be interesting to compare the mineral intake between children living in endemic areas and in non-endemic areas. It would also be interesting to include more of elements known to affect bone metabolism in future studies. [less ▲]

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See detailLe droit coutumier dans les ordres juridiques contemporains (19e-21e siècles). Étude comparative des pratiques judiciaires et de la doctrine
Braillon, Charlotte ULg

Doctoral thesis (2016)

The study questions the concept of customary law and its interventions in contemporary legal orders. From an historical perspective, it offers to approach this question at the light of a comparison ... [more ▼]

The study questions the concept of customary law and its interventions in contemporary legal orders. From an historical perspective, it offers to approach this question at the light of a comparison between the legal doctrine (theory of customary law) and the judicial practice (decision on the content of customary law). After a preliminary part dedicated to a synthesis of the legal grounds of customary law in contemporary legal orders, the first part of the study analyses the developments of a theory of customary law in legal doctrines, after the era of the Ancien Regime. A second part compares doctrinal creations to contemporary practices, through a selection of case studies, mainly in the practice of colonial law in the Belgian Congo and in the case law of the International Court of Justice. These first case studies share an expression of the theory of customary law in practice: whereas the practictioner may unofficially step in the creation of customary law, the decision is grounded, at least to all appearances, on this theory. The third and last part of the study, on the other hand, presents several cases, also selected from the contemporary practice, where judicial decisions share the fact that they are grounded on moral elements – which are not considered in the theory –, and therefore illustrates a more explicit intervention of the magistrates. These cases originate in the case law of the public prosecutor’s court in the Belgian Congo and the International Criminal Tribunal for the ex-Yougoslavia. [less ▲]

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See detailActivation de la coagulation par la Transition Epithélio-Mésenchymateuse: impact sur la colonisation métastatique
Bourcy, Morgane ULg

Doctoral thesis (2016)

Au cours de la cascade métastatique, des cellules tumorales quittent la tumeur primaire et envahissent le sang (Cellules Tumorales Circulantes, CTCs) pour former des métastases dans des organes ... [more ▼]

Au cours de la cascade métastatique, des cellules tumorales quittent la tumeur primaire et envahissent le sang (Cellules Tumorales Circulantes, CTCs) pour former des métastases dans des organes secondaires. Le processus métastatique est hautement sélectif et seule une faible proportion de CTCs survit dans la circulation et colonise les sites secondaires pour former des métastases. Les cellules tumorales subissent des changements phénotypiques qui leur procurent des propriétés migratoires et invasives ainsi que des capacités de survie accrue leur permettant de franchir ces différentes étapes. A ce jour, il est largement accepté que les processus de Transition Epithélio-Mésenchymateuse (TEM) sont impliqués dans cette plasticité cellulaire et participent à la libération et à la biologie des CTCs. Des données de la littérature indépendantes ainsi que des résultats du laboratoire suggèrent, par ailleurs, que les processus de coagulation pourraient favoriser les étapes précoces de la dissémination métastatique (survie, persistance, arrêt et extravasation). Au cours de ce travail de doctorat, nous avons examiné l’acquisition potentielle de propriétés pro-coagulantes par les CTCs dérivées d’une TEM impliquant l’expression du Facteur Tissulaire (FT), l’initiateur cellulaire clé de la cascade de coagulation. De telles propriétés coagulantes permettraient la formation d’une matrice de fibrine protectrice autour des CTCs favorisant, ainsi, leur survie dans la circulation sanguine et la colonisation métastatique. A l’aide de divers modèles cellulaires in vitro, nous avons montré que les processus de TEM sont associés à une expression accrue du FT et à des propriétés pro-coagulantes. Ensuite, nous avons fonctionnellement lié les processus de TEM à ces régulations en y impliquant des facteurs de transcription de la TEM, ZEB1 et Snail. De plus, en utilisant des modèles de métastases expérimentales, nous avons montré que l’axe TEM/FT/coagulation procure aux CTCs des propriétés de survie et des capacités de colonisation métastatique accrues. Enfin, nous avons apporté une validation clinique à ces résultats en observant des CTCs positives pour le FT et la vimentine, un marqueur mésenchymateux, dans le sang de patientes atteintes d’un cancer du sein métastatique. L’ensemble de nos résultats met en évidence un nouvel axe de régulation TEM/FT permettant une activation locale de la coagulation par les CTCs TEM+ favorisant la colonisation métastatique précoce. [less ▲]

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