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See detailElaboration d’un protocole in vitro de contournement des barrières d’incompatibilité génétique entre Phaseolus coccineus L. et P. vulgaris L.
Barikissou, Eugénie ULg

Doctoral thesis (2012)

L’amélioration du haricot commun Phaseolus vulgaris L. par hybridations interspécifiques avec P. coccineus L. nécessite l’utilisation de ce dernier comme parent femelle (♀). Mais ce croisement aboutit ... [more ▼]

L’amélioration du haricot commun Phaseolus vulgaris L. par hybridations interspécifiques avec P. coccineus L. nécessite l’utilisation de ce dernier comme parent femelle (♀). Mais ce croisement aboutit souvent à des avortements et ce, dès le stade globulaire. L’embryoculture permet d’obtenir, dans certains cas, des hybrides interspécifiques via la culture d’embryons isolés aux stades cordiforme âgé ou cotylédonaire, mais pas au stade globulaire. A ce dernier stade de développement, il a été possible d’obtenir des plantes chez le génotype NI 637 de P. vulgaris, via le protocole de culture de gousses. Mais l’absence de formation de racines chez les embryons germés, qui devraient évoluer en plantules, a limité le taux de réussite à un pourcentage de 3% de plantules en croissance. L’objectif de notre travail est d’améliorer ce taux afin de parvenir à sauver efficacement les embryons hybrides P. coccineus (♀) x P. vulgaris. Nous avons tout d’abord étudié les conditions de régénération in vitro des embryons obtenus par autofécondations, pour les appliquer ensuite aux embryons hybrides interspécifiques. Différents essais ont été réalisés sur base du protocole de culture de gousses. Ce protocole consiste à réaliser la culture de jeunes gousses successivement sur trois milieux à osmolarité décroissante et nommés : P00 (à 580 mosm), P01 (à 450 mosm) et P01 (à 350 mosm). Après une semaine de culture les embryons sont isolés des gousses puis transférés successivement sur les milieux G1 de maturation et germination, G6 de déshydratation, G7g d’induction de racines et G7c de développement en plantules. L’évaluation de ce protocole de culture de gousses chez trois génotypes : NI 637, NI 622 et X 484 de P. vulgaris et un génotype NI 16 de P. coccineus, nous a permis de confirmer les difficultés d’enracinement des embryons germés, comme rapportées auparavant chez NI 637. Toutefois, le retrait de la BAP (0,1 µM) du milieu G1 et la culture, au-dessus du milieu des embryons isolés, ont permis d’obtenir un taux de germination de 91%, c’est-à-dire un taux deux fois plus élevé par rapport au résultats rapportés antérieurement chez NI 637. La culture préalable des embryons en milieu G1 liquide a favorisé, après leur transfert successif sur les milieux gélosés G6, G7g et G7c, l’enracinement et le développement en plantules, en réduisant le brunissement du milieu et la formation de cals. Cela nous a permis d’obtenir un taux de 10% de plantules en croissance, taux trois fois plus élevé par rapport à celui rapporté auparavant en milieu gélosé. Toutes les plantules obtenues, par culture préalable en milieu liquide, ont développé des plantes adultes après un mois d’acclimatation. La culture des embryons en milieu gélosé et l’ajout du charbon actif dans les deux milieux G7g et G7c ont également permis de réduire le brunissement et la formation de cals. Cela a donné un taux de plantules en croissance de 60%, c’est-à-dire un taux 20 fois plus élevé par rapport à celui rapporté auparavant sans charbon actif. Le microbouturage de nœuds cotylédonaires, combiné au protocole de culture de gousses, a permis de régénérer des plantules chez tous les génotypes testés, avec un taux de régénération plus élevé chez NI 16 de P. coccineus (90%) par rapport à P. vulgaris (50%). Cela représente un taux de régénération trois fois plus élevé par rapport au résultat rapporté auparavant avec la culture de gousses seule chez le génotype NI 637 de P. vulgaris. La culture in vitro des embryons en cours d’avortement et isolés de l’ovule au stade cordiforme jeune, combinée au microbouturage de nœuds cotylédonaires, nous a permis d’obtenir, pour la première fois, une plantule hybride P. coccineus (NI 16) x P. vulgaris (NI 637). Notre protocole, qui combine le protocole de culture de gousses et le microbouturage de nœuds cotylédonaires, pourrait être une alternative intéressante pour le sauvetage d’embryons qui avortent au stade globulaire. [less ▲]

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See detailDegradation mechanisms of Prussian blue pigments in paint layers
Samain, Louise ULg

Doctoral thesis (2012)

Prussian blue is a modern synthetic pigment discovered in Berlin at the beginning of the eighteenth century. Prussian blue is a hydrated iron(III) hexacyanoferrate(II) complex and its color results from ... [more ▼]

Prussian blue is a modern synthetic pigment discovered in Berlin at the beginning of the eighteenth century. Prussian blue is a hydrated iron(III) hexacyanoferrate(II) complex and its color results from an intervalence charge transfer between the iron(II) and iron(III) ions when light is absorbed at ca. 700 nm. Because of both its highly intense color and its low cost, Prussian blue enjoyed immediate popularity among artists and was widely used as a pigment in paintings until the 1970's. However, the permanence of Prussian blue had already been questioned by the mid-eighteenth century, because it exhibits a tendency to fade in light and to turn green. The preparative methods were rapidly recognized as a contributory factor in the fading of the pigment. The main objective of this thesis is the identification of the degradation mechanisms of Prussian blue pigments in paint layers. Prussian blue was synthesized according to both ancient and modern preparation methods. A thorough analysis of the pigments revealed a dependency upon the type of synthesis, the crystallite size, and vacancy content, all properties that influence the local electronic and structural configurations of the iron ions in Prussian blue. The presence of nanocrystalline ferrihydrite as an undesirable iron containing reaction product was identified in Prussian blue pigments prepared according to eighteenth-century recipes. Discoloration upon light exposure in Prussian blue paint layers was induced by accelerated ageing. Pure Prussian blue painted in a dark shade is extremely light fast but fades when either painted in a lighter shade or mixed with white pigments. The fading of Prussian blue was attributed to a reduction of the iron(III) ions at the surface of the paint layer. A partial oxidation of Prussian blue in the entire paint layer was also observed. The analysis of works of art containing Prussian blue confirmed the combined oxidation and reduction of Prussian blue iron ions upon ageing. The study of alteration mechanisms in a painting pigment is essential both for conservation and historical studies in order to best preserve our cultural and artistic heritage with respect to an artist’s original intentions. [less ▲]

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See detailEtude pluridisciplinaire de l'implication bactérienne du phénomène de blanchissement des coraux Scléractiniaires (Indo-Pacifique)
Ladrière, Ophélie ULg

Doctoral thesis (2012)

Given the increasing number of coral diseases linked to the growing impact of global warming and human activities, the present research focused on the phenomenon of coral bleaching. The Scleractinian ... [more ▼]

Given the increasing number of coral diseases linked to the growing impact of global warming and human activities, the present research focused on the phenomenon of coral bleaching. The Scleractinian Cnidaria are the essential building blocks of the coral reef ecosystem, whose ecological, economic and societal interests are demonstrated. The symptom of bleaching has multiple and complex causes that are still unclear. It corresponds to the rupture of the mutualistic symbiosis between the coral and microalgae, called zooxanthellae, and can causes death of many corals. An assumption underlying this phenomenon suggests that corals are bleaching by the action of pathogenic bacteria, penetrating inside the coral tissues. However, this hypothesis seems quite controversial and the present work attempts to elucidate a set of issues surrounding this controversy. To do this, a multidisciplinary approach combining ecology (general and microbial) and molecular biology has been established through field and experimental studies. Using electron microscopy, morphological criteria were established to characterize the status of coral bleaching. Furthermore, this technique was also used to identify different types of bacteria within coral tissues. Their presence and their role within the coral holobiont were discussed. Several molecular biology techniques (DGGE, sequencing) have provided evidences on the non-specificity of bacterial communities associated with corals species, sampling sites and different status of bleaching. This non-specificity shows that the functions performed by bacteria in the coral holobiont could be the result of opportunistic bacteria from various taxonomic groups. The presence of Cyanobacteria in some corals, detected by microscopy and confirmed by molecular techniques, raises the question about their role within the holobiont and the alternative pathway that they offer for the symbiotic host compared with zooxanthellae. The issues of potential competition between these different symbionts or the benefit of this symbiotic diversity, in case of bleaching event, remain open. Transcriptomic genetics was used to study the response of coral facing a bacterial stress in different experimental conditions of temperature determining the expression of bacterial virulence. Studying the expression profile of genes involved in immunity of the coral allowed to understand the sequence of reactions and changes in resource allocation in response to different stages of bacterial infection. On this experiment, the first antimicrobial peptide of Scleractinia, the damicornin, has been identified and characterized. All these results suggest that the context of changes in environmental parameters is more important than the presence of pathogens itself. The bacteria would then act as an aggravating factor in a situation where the coral, already weakened and stressed, cannot defend itself adequately. Finally, the observation of an increase in cnidocytes in a coral species that has undergone bleaching, suggests that some coral species are able to shift to a more heterotrophic nutritional regime adapting to the lack of inputs caused by the significant loss of zooxanthellae. This would favor the resilience of coral. [less ▲]

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See detailImmuno-inflammatory mechanisms in refractory asthma
Manise, Maïté ULg

Doctoral thesis (2012)

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See detailApplications de la résonance magnétique nucléaire à la chimie des actinides et au retraitement des combustibles nucléaires.
Vidick, Geoffrey ULg

Doctoral thesis (2012)

This research work is dedicated to develop and bring to light the contribution of nuclear magnetic resonance (NMR) in the study of the actinide ions and their complexes in aqueous or in organic solvents ... [more ▼]

This research work is dedicated to develop and bring to light the contribution of nuclear magnetic resonance (NMR) in the study of the actinide ions and their complexes in aqueous or in organic solvents. We use several advanced NMR techniques. The dispersion of the longitudinal relaxation time T1 of solvent nuclei with the magnetic field (NMRD) yields information on the magnetic properties of paramagnetic actinide ions. The sensitivity of NMR to the exact nature of the ground state of actinide ions is also illustrated by detailed studies on the complexes of U, Np, Pu, Am and Cm in different oxidation states. It will be shown that the paramagnetic shifts induced by the actinide ions originate from both a through space dipolar contribution and a through bonds contact contribution. The latter gives access to delocalized unpaired electron densities that are directly related to the covalency of the actinide-ligand bonds. However, electronic densities can only be obtained after separation of the two contributions. This separation made thanks three different methods based on studies with variable temperature and by synthesizing highly symmetric and anisotropic complexes. The use of dipolar contribution can be, as for her, related to the geometry of complexes formed in solution. This method of determination of solution structure is illustrated in the case of four specially designed N-polyaromatic ligands actinide/lanthanide partitioning by liquid-liquid extraction, an essential step for the ultimate nuclear fuel reprocessing. Besides their structure determination, the use of NMR techniques allowed of determined the stoechiometry and speciation in solution of these complexes. [less ▲]

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See detailDispersal ability and speciation mechanisms in bryophytes
Hutsemekers, Virginie ULg

Doctoral thesis (2012)

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See detailÉvolution des effectifs des populations d’éléphants d’Afrique soudanosahélienne :enjeux pour leur conservation
Bouché, Philippe ULg

Doctoral thesis (2012)

The first objective of this thesis was to analyze the evolution of Sudano-Sahelian African elephant populations in a context of environmental challenges and increasing human demography. The second ... [more ▼]

The first objective of this thesis was to analyze the evolution of Sudano-Sahelian African elephant populations in a context of environmental challenges and increasing human demography. The second objective was to propose solutions for elephant conservation in the Sudano-Sahelian context. To fulfill these objectives, aerial surveys have been carried out in every protected area harboring a known population of elephants. This work was first implemented at a local level on several study cases and finally at a global level. Results of aerial surveys estimate the current elephant number at minimum 7,745 elephants, about 2% of the African elephant total population. This confirmed that the elephant populations have been progressively fragmented and confined to few protected areas representing 5% of the Soudano-Sahelian strip. The long term (four decades) elephant population trends has been studied by comparing our results with the database of the study area. The half of the monitored population collapse during the last 40 years. The viability of small elephant population of 200 elephants and below is critical and several of them collapsed. Contrasted local situation have been observed : if a number depletion is often observed, in some protected areas elephant populations are stable or increasing. Although, trends of other large mammals’ population is not linked to that of the elephants. This result allow to conclude that the elephant is not a good indicator of the abundance of other large mammals’ population. Causes of elephant populations’ depletion are both due to climate change (global drought) and socio-economic (human demography and land use pressure) issues. An appropriate and permanent field management, a better valorisation of elephants and the creation of negotiated corridors with local people could garantee the future of Sudano-Sahelian African elephants. [less ▲]

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See detailCaractérisation des espaces périurbains, morphologie actuelle et prospective
De Smet, Fabian ULg

Doctoral thesis (2012)

L’étalement urbain est un défi majeur pour nos territoires européens et plus spécifiquement belges. Il se concrétise par l’urbanisation massive de territoires périphériques de villes, appelés espaces ... [more ▼]

L’étalement urbain est un défi majeur pour nos territoires européens et plus spécifiquement belges. Il se concrétise par l’urbanisation massive de territoires périphériques de villes, appelés espaces périurbains. Cette urbanisation a des conséquences multiples, notamment en termes architecturaux et urbanistiques. Nous avons défini la forme périurbaine comme un état de l’évolution des espaces périurbains, formulé à partir de leurs composantes bâties et de leur organisation. Dans ce contexte, l’objectif principal de cette thèse est l’amélioration de la connaissance de la forme périurbaine. En d’autres termes, il s’agit de contribuer à l’émergence d’un cadre de réflexion sur l’actualité et l’avenir morphologique des espaces périurbains. Pour nous, il s’agit d’un préalable indispensable à la gestion des caractères architecturaux et urbanistiques de ces espaces. Afin d’apporter notre contribution à la construction de ce cadre de réflexion, nous avons structuré notre démarche scientifique autour de trois objectifs plus spécifiques. Ceux-ci structurent cette thèse. Le premier de ces objectifs est l’évaluation de la connaissance et de la reconnaissance des spécificités des espaces périurbains. Dans la première partie de cette thèse, nous nous sommes attaché à faire l’état de la connaissance des espaces périurbains et des concepts qui sont mobilisés pour les décrire. Ainsi, le second chapitre de notre dissertation dresse un bilan critique des connaissances relatives aux espaces périurbains. Dans le troisième chapitre, nous mettons en perspective le vocabulaire mobilisé dans leur description et leur gestion légale et opératoire. Le second objectif de cette thèse est le développement d’un outil d’analyse des tissus bâtis périurbains. Ainsi, le quatrième chapitre de la dissertation porte plus spécifiquement sur les formes périurbaines et leur analyse. Nous y développons la méthode d’observation et d’analyse morphologique de l’espace périurbain que nous avons construite et testée sur l’espace périurbain liégeois. Nous en explicitons le développement et en commentons les résultats. Cette méthode nous a permis de construire une typologie des tissus bâtis périurbains et, ainsi, de proposer un cadre de caractérisation de la forme périurbaine. Le troisième objectif est la proposition de scénarios prospectifs quant aux avenirs possibles de la forme périurbaine. Dans le cinquième chapitre de cette dissertation nous nous sommes intéressé à l’utilisation des résultats de la classification typologique à des fins de simulations prospectives. Sur base de ces résultats, nous avons construit des scénarios d’évolution potentielle de l’urbanisation périurbaine et de la forme périurbaine. [less ▲]

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See detail"Identification organisationnelle et changement: les logiques identitaires à l'épreuve du New Public Management"
Rondeaux, Giseline ULg

Doctoral thesis (2012)

Depuis près de 30 ans, nombre de pays se sont engagés dans la réforme de leur administration publique, inspirée du New Public Management (NPM), inspirant de multiples travaux et débats sur ses fondements ... [more ▼]

Depuis près de 30 ans, nombre de pays se sont engagés dans la réforme de leur administration publique, inspirée du New Public Management (NPM), inspirant de multiples travaux et débats sur ses fondements et ses déclinaisons, ses avantages et inconvénients, sa pertinence, ses paradoxes ou encore les difficultés liées à sa mise en oeuvre ou à son évaluation. Construit comme une critique des règles de l’administration bureaucratique, ce modèle managérial constitue une profonde remise en cause de celle-ci en termes d’organisation, de management, de GRH et de valeurs fondamentales. Les réformes inspirées du NPM sont aussi à la base d’une redéfinition de l’identité organisationnelle institutionnalisée de l’administration (Du Gay, 1996) : l’organisation s’interroge sur ce qu’elle est, ce qu’elle devient, ce qu’elle veut être, propulsant l’identité organisationnelle au premier plan des préoccupations. Alors que le processus de modernisation de l’administration vise à redéfinir la réponse à la question « qui sommes-nous en tant qu’organisation ? », de quelle manière les membres de celle-ci en font-ils l’expérience? Au travers de l’analyse de trois cas de réforme d’administrations publiques, notre thèse s’intéresse aux dynamiques d’identification à l’oeuvre en regard de la perception des évolutions du contexte par les individus. Nous mettons en évidence le lien qui existe entre les processus d’identification organisationnelle et deux dimensions spécifiques à chaque contexte en évolution : le caractère plus ou moins radical de changement d’identité organisationnelle institutionnalisée que suppose la réforme mise en œuvre, et le degré de maturité de ce processus de réforme, ou en d’autres termes la mesure dans laquelle la réforme est plus ou moins perceptible dans la transformation du contexte même. Au départ des différents éléments relevés dans chacun de nos terrains, notre thèse illustre concrètement comment la mise en œuvre d’un management polyphonique du processus de changement peut contribuer de manière positive à l’identification organisationnelle des membres de ces organisations en évolution. Cette approche mène à réfléchir autrement à la gestion du changement au travers de la prise en compte de cette diversité de positionnements identitaires. Elle conduit en outre à une réflexion plus large sur la mise en œuvre du NPM et sur l’administration publique de demain. [less ▲]

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See detailFeeding and ranging behavior of northern pigtailed macaques (Macaca leonina): impact on their seed dispersal effectiveness and ecological contribution in a tropical rainforest at Khao Yai National Park, Thailand
Albert, Aurélie ULg

Doctoral thesis (2012)

Southeast Asia experiences an exceptional loss of natural habitat due to a deforestation rate that strongly increased during the last decades. The first consequence is the loss of many animal and plant ... [more ▼]

Southeast Asia experiences an exceptional loss of natural habitat due to a deforestation rate that strongly increased during the last decades. The first consequence is the loss of many animal and plant species, threatened by their habitat degradation and by the loss of interactions necessary to the survival of the whole ecosystem. Large mammals and birds populations, the principal dispersal agent of some plant species, already collapsed massively due to hunting and habitat fragmentation and now threaten to die out. Among the large frugivorous species, primates are particularly vulnerable. Only few species, such as macaques, are able to survive in some man-made habitats, due to their opportunistic life-style. But, in the long term, habitat destruction, hunting and capture for local trade threaten their survival. The extinction of primates in Southeast Asian forests would be disastrous for many plant species as primates are among the major seed-dispersal agents. The study of Macaca, the only Cercopithecinae genus in Southeast Asia, could provide a better understanding of the role of cheek-pouched monkeys in tropical rainforest maintenance and restoration. In this study, we chose to focus on northern pigtailed macaques (Macaca leonina) as few studies were carried out on this species, making data concerning its ecology and behavior highly limited. Their seed dispersal capacity, although unknown, is potentially high and pigtailed macaques could be as good seed dispersers as sympatric frugivores. They seem to eat a large number of fruits of many plant species, process seeds with care, and range daily over large areas. Moreover they could have a role in forest maintenance and regeneration given that they seem to eat species with all seed sizes, belonging to all plant life forms present in the forest, and they are able to cross various habitat types (primary as well as secondary forests). After providing an outline of our current knowledge on seed dispersal by Cercopithecinae species and their specific role in forest regeneration, our aim was to highlight the importance of northern pigtailed macaques on seed dispersal and thus on forest regeneration by studying (1) how their eco-ethological characteristics can make them effective dispersers, from a quantitative and a qualitative point of view, (2) how the influence of biotic factors, such as resources and predation, on their activities and movements may impact their seed dispersal effectiveness, and (3) what role Macaca spp. can have in a seed dispersal assemblage. While following a troop of northern pigtailed macaques habituated to humans in Khao Yai National Park, Thailand, we recorded their behavior, travels, and consumed items, from dawn to dusk. Moreover, we studied the spatio-temporal distribution of fruits included in their diet, and the characteristics of their sleeping sites. Finally, we performed germination and viability tests on ingested seeds. Results showed that northern pigtailed macaques could disperse thousands of seeds, up to 58 mm in length, coming from the 126 fruit species they eat. Especially, they could disperse them from primary to secondary forest, thanks to handling techniques such as swallowing, spitting and dropping. Finally, the seed passage through their digestive tract mostly had a neutral or positive effect on seed germination and viability. Macaques observed in this study satisfied therefore most requirements defining effective seed dispersers in both quantitative and qualitative terms and we can conclude to the potential importance of Macaca leonina in the tropical rainforest regeneration. To confirm the seed dispersal effectiveness of M. leonina, we needed to make sure that its ranging behavior did not negatively affect dispersed seeds. Moreover, given the importance of human food in their diet, we wondered if this resource had a negative impact on seed dispersal. Our results showed that northern pigtailed macaques adapted their ranging pattern according to fruit availability. Moreover, during fruit scarcity, they shifted their diet from frugivorous to omnivorous with an important part of human food. However, human food did not seem to have an impact on seed dispersal in high fruit abundance periods where macaques had a large home range, traveled long distances and ate mainly fruits. However, in low fruit abundance periods, macaques decreased their home range size, traveled shorter distances and ate mainly human food. This latter could have a negative impact on the seed dispersal of some rare fructifying species. However, these species were eaten by many other animal species able to provide good dispersal services. Then, we showed that sleeping sites characteristics and pre-sleep behavior in M. leonina were influenced by the proximity of resources and the risk of predation. Given that macaques used few sleeping sites, defecated when they woke up and that all troop members slept concentrated in a small area, we think that they created a high seed density below the sleeping trees. This may be harmful for some seed species but may be beneficial for the ecosystem. Moreover, this pattern may be shown in other effective seed dispersers in the park. So as harmful for seeds it may be, it does not make pigtailed macaques less effective than other frugivores. Finally, we demonstrated that Macaca species are important associates in the seed dispersal assemblage found in Southeast Asian forests. Indeed they may disperse most plant species, usually more efficiently dispersed by other frugivores, and thus provide a significant complement in term of dispersal quantity. Moreover, they are sometimes the only frugivores able to disperse the seeds of some species, mainly large-seeded and/or protected ones, and may thus bring them a vital dispersal service. [less ▲]

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See detailModèles d'écoulements incompressibles en plan vertical appliqués aux structures du génie civil
Detrembleur, Sylvain ULg

Doctoral thesis (2012)

Le travail entrepris s’intègre complètement dans la filière d’étude propre au HACH, à savoir une interaction étroite entre modèles numériques et validation sur bases d’éléments issus de la modélisation ... [more ▼]

Le travail entrepris s’intègre complètement dans la filière d’étude propre au HACH, à savoir une interaction étroite entre modèles numériques et validation sur bases d’éléments issus de la modélisation physique. Les hypothèses restrictives du modèle intégré sur la hauteur (WOLF2D) ont été gommées par l’ajout de deux nouveaux modules permettant de calculer explicitement la distribution des variables hydrodynamiques sur la hauteur de l’écoulement. L’utilisation intensive du code bidimensionnel horizontal et les modélisations diverses et variées menées au moyen de ce module ont conduit à de nombreuses implémentations nouvelles dans ce code, permettant de traiter un nombre grandissant de situations complexes. L’utilisation d’un maillage structuré, même différentiable spatialement au moyen d’une technique multiblocs, ne permet cependant pas à l’utilisateur de représenter adéquatement certaines géométries complexes. Il ressort de ce constat que les techniques numériques à même de supprimer cette dépendance ont fait l’objet d’une partie de cette recherche, en permettant l’utilisation de contours quelconques qui ne respectent pas nécessairement la structure cartésienne du maillage. Ces développements ont tout naturellement conduit à la modélisation d’interactions de structures solides sur le fluide. D’autre part, le grand nombre de modèles hydrodynamiques spécifiques implémentés dans le code WOLF2D trahissent une volonté d’intégrer les variations verticales des composantes hydrodynamiques agglomérées par l’intégration sur la hauteur. Ces distributions peuvent, certes, être maîtrisées dans une certaine mesure, mais ne peuvent en aucun cas reproduire la dynamique complexe qui est observée dans la direction d’intégration de ce type de modèle. Par conséquent, la partie principale des recherches entreprises dans cette thèse est concentrée sur le développement d’un modèle bidimensionnel explicitement discrétisé sur la verticale (WOLF2DV) qui permet de combler le manque d’informations distribuées induit lors de l’élaboration d’un modèle bidimensionnel horizontal. L’obtention de ces informations a cependant un coût, puisque la structure et la technique de résolution du système d’équations est différente des modèles intégrés sur la hauteur ou sur la section et engendre des coûts de calcul supplémentaires. Afin de conserver la philosophie générale de la suite logicielle WOLF, qui se veut polyvalente et efficace même sur de grandes applications réelles, un effort considérable a été consenti lors de l’évaluation des techniques de résolution et de leur implémentation et ce, afin de conserver des temps de calcul acceptables. En outre, la volonté de s’affranchir de la discrétisation sur des maillages structurés transparaît également au niveau des recherches entreprises pour ce code explicitement discrétisé sur la verticale puisqu’un second challenge important a consisté en l’élaboration d’une technique de suivi d’interface adaptée. Finalement, les résultats probants et prometteurs fournis ont amené tout naturellement à étendre ce module bidimensionnel vers la troisième dimension et à ainsi représenter explicitement un écoulement tridimensionnel (WOLF3D). Compte tenu de la lourdeur de développement dans la troisième dimension, ce module est limité aux écoulements sous pression et constitue la base de recherches futures qui viseront à adjoindre à ce code une gestion de surface libre ou encore des modèles de turbulence. [less ▲]

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See detailAfter Melancholia: A Reappraisal of Second-Generation Diasporic Subjectivity in the Work of Jhumpa Lahiri
Munos, Delphine ULg

Doctoral thesis (2012)

While Jhumpa Lahiri’s work might be thought of as one of the most emblematic instances of the popularity of today’s Indian-American diasporic literature, it remains that its hyper-visibility coincides ... [more ▼]

While Jhumpa Lahiri’s work might be thought of as one of the most emblematic instances of the popularity of today’s Indian-American diasporic literature, it remains that its hyper-visibility coincides with an odd form of critical invisibility. This is not to say that critical interventions on Lahiri’s three books have been nonexistent, nor could they have been in view of the fact that the author won the Pulitzer Prize in 2000 for her first collection of short-stories, Interpreter of Maladies. But the vast majority of these readings takes as its premise that view that cultural assimilation and hybridity are still valid notions to investigate narratives focusing on members of the second generation, even as these descendants of migrants consider themselves Indian simply by virtue of their parents, so that they can only claim a second-hand knowledge of migration. Ignoring the difference between first and second-generation Indian-American diasporic experiences – and, what is more, overlooking the fact that the offspring of migrants, unlike their parents, “[do] not really have any other place [than the U.S.] to call home” (Lahiri) – such critical consensus ignores important aspects of Gogol’s complex trajectory in The Namesake. Worse, it proves highly unsatisfactory when it comes to discussing Lahiri’s recent collection of short stories, Unaccustomed Earth, in which the second generation’s accession to early middle age calls into question various preconceptions on heritage and transmission. Can it be then that what is passed on from one generation to the next organizes itself less around positive, than negative entities, that is, around categories such as the gap, the absent, and the unsaid? Taking its cue from Vijay Mishra’s understanding of the diasporic subjectivity in terms of an impossible mourning, my dissertation examines the ways in which Lahiri redefines the notions of belonging and arrival as regards the Indian-American second generation not in terms of cultural assimilation – which would hardly make sense for characters who were born in the U.S. in the first place – but in terms of a re-symbolization of the gaps in the parents’ migrant narratives, more particularly in terms of the “phantom loss” haunting transgenerational relationships between migrants and their offspring. While investigating the figures of emptiness, spectrality, and the message, my dissertation takes various psychoanalytic theories by Sigmund Freud, Julia Kristeva, Nicolas Abraham, Maria Torok and Jean Laplanche, among others, as its major methodological tools. As against a critical consensus that overemphasizes matters of culture, such theoretical framework aims to revaluate the power of the literary in Lahiri’s work. Although this dissertation extends, at times, to Lahiri’s three books, its four chapters boil down to a close reading of the three texts constituting the “Hema and Kaushik” trilogy, which also form part 2 of Lahiri’s 2008 collection of short stories, Unaccustomed Earth. Through these three narratives, which all traffic with the dead-mother metaphor, Lahiri can be seen to inscribe the dimension of mourning at the heart of her approach to “generational arrival.” The three short stories of “Hema and Kaushik” indeed bring to the fore some unacknowledged facets of the much-idealized diasporic experience, which forces us to revise the cultural scenarios through which today’s contemporary world constructs, even essentializes, the figure of the migrant as an emblem of ultimate freedom. My close reading of “Hema and Kaushik” falls into four parts. Part 1 looks at “Once in a Lifetime,” the first text of Lahiri’s trilogy, with a view to showing how the apostrophic form of the text opens up a space of mourning which might blur the boundaries between absence and presence, return and arrival, self and other, but also positions Kaushik, for Hema, as a transitionary figure whose absence might well prove crucial in letting Hema-as-narrator acquire her own generational voice. Part 2 is devoted to “Year’s End,” and investigates the ways in which Lahiri employs the Gothic to represent the second generation as being haunted by its own belatedness in relation to the first generation’s experiences. The psychoanalytic theories of Nicolas Abraham and Maria Torok, among others, will help me clarify how the dead-mother metaphor, in “Hema and Kaushik,” proves tightly interweaved with notions of transgenerational transmission, connection, and infiltration. Calling into question the possible unity of the “I” in the second text of the trilogy, Part 3 tracks the mole, so to speak, and bears witness to aspects of Lahiri’s work that are not all “in the words,” but “among the words,” to borrow Marcel Proust’s suggestive phrase, notably by revisiting aspects of “Once in a Lifetime” and “Years’ End” that are given a new significance through the interplay of the three texts of the trilogy. Relying on André Green’s concept of the “dead mother,” I will then propose an alternative reading of Lahiri’s trilogy in which Hema’s and Kaushik’s romance is only a surface-plot, enlisted to give representability to “the great unspeakable” of Hema’s life. In Part 4, Jean Laplanche’s description of the formation of the ego and the unconscious in relation to “early messages of the m/other” will allow me to look behind the curtain of transgenerational forms of melancholia, to that place where infinite longing is shown to organize itself not around any “real thing” but around a phantom entity whose idealization covers up the necessity to grapple with one’s involvement in a history of loss, which is also a history of guilt. [less ▲]

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See detailApplication of molecular tools to study the hydrogen production by the bacteria of the genus Clostridium
Calusinska, Magdalena ULg

Doctoral thesis (2012)

L’hydrogène moléculaire a un potential énorme comme futur vecteur énergétique car sa combustion n’est pas polluante. Cependant, les processus industriels actuels de production contribuent ... [more ▼]

L’hydrogène moléculaire a un potential énorme comme futur vecteur énergétique car sa combustion n’est pas polluante. Cependant, les processus industriels actuels de production contribuent substantiellement à l’effet de serre. Au contraire, une production d’H2 qui est neutre en CO2 peut être obtenue par la fermentation anaérobique obscure. Les bactéries du genre Clostridium peuvent fermenter les sucres en H2 et CO2 avec production d’ acide acétique et butyrique qui servent d’accepteurs principaux d’électrons. Cependant, en fonction de la souche/co-culture utilisée et des conditions de culture, des composés plus réduits peuvent être obtenus, par ex. l’éthanol, le lactate, ce qui réduit substantiellement le rendement final en H2. De plus, les différentes voies métaboliques et les circuits de régulation conduisant à la production d’H2 dans les clostridies ne sont pas bien connus. Dans cette étude, nous avons étudié deux sujets principaux. D’une part, nous avons étudié différentes co-cultures de Clostridium spp. dans des bioréacteurs produisant de l’H2. En suivant les co-cultures de C. butyricum et C. pasteurianum par FISH (Fluorescence in situ hybridisation) et qPCR (quantitative real-time PCR), nous avons montré que les deux espèces co-existent de manière stable durant la fermentation de différents sucres dans deux bioréacteurs. D’autre part, en utilisant Clostridium butyricum CWBI1009 comme modèle, nous avons étudié le métabolisme complexe de l’H2 chez les clostridies. La découverte de gènes nouveaux codant pour des hydrogènases [FeFe] dans les génomes séquencés a changé notre vue de la façon dont ces microbes produisent l’ H2. En effet, en utilisant différents outils moléculaires (2D-DIGE, RT-qPCR et RNA-seq), nous avons montré que dans différents conditions de milieu, différentes hydrogénases contribuent à la production d’H2. De plus, sous atmosphère d’N2 pendant la fermentation du glucose dans des conditions de pH non régulées, nous observons que la nitrogénase contribue à la production globale d’H2. De manière surprenante, alors que les clostridies semblent bien équipées pour produire de l’H2, elles n’ont probablement développé cette capacité que pour s’adapter rapidement aux variations de conditions, cad la diminution du pH. Donc, pour maintenir un pH intracellulaire constant, elles rejettent les protons (sans doute sous forme de H2) dans le milieu. Ainsi, elles se débarrassent de l’excès d’équivalents réducteurs produits pendant la fermentation du glucose. En résumé, nos résultats contribuent à une meilleure connaissance du métabolisme complexe de l’H2 chez les clostridies. Cependant, un défi pour le futur consiste à caractériser les enzymes responsables de ce métabolisme et, par bioengineering métabolique, de développer des systèmes microbiens optimaux pour la conversion de la biomasse en H2. [less ▲]

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See detailTraverser la Belgique ? De l'Indépendance au Plan Schlieffen (1839-1905)
Bechet, Christophe ULg

Doctoral thesis (2012)

La question des voies de communication belges liée à la politique de défense du pays et aux plans de guerre des puissances voisines n’avait encore jamais fait l’objet d’une recherche systématique pour ... [more ▼]

La question des voies de communication belges liée à la politique de défense du pays et aux plans de guerre des puissances voisines n’avait encore jamais fait l’objet d’une recherche systématique pour cette période importante qui s’étend de l’indépendance de la Belgique à l’aube du premier conflit mondial. L’étude de cette problématique est étroitement liée à celle des perceptions entretenues au sein des milieux diplomatiques et militaires des deux grandes puissances voisines de la Belgique ; la rivalité franco-allemande tout au long du 19e – début 20e siècle a en effet induit un questionnement continuel des diplomates et des hommes de guerre français et allemands sur le rôle de l’espace belge en cas de guerre future. Par un effet de balancier, ces perceptions étrangères ont elles-même influencé en retour les réflexions stratégiques de la diplomatie et du milieu militaire belge et in fine la politique défensive du pays. Afin de vaincre l’apparente hétérogénéité de l'objet d'étude comme les difficultés liées à la longueur de la période choisie, le concept de « traversée » du territoire belge entre la France et l’Allemagne s’est imposé comme l’axe de réflexion idéal, capable de réunir dans un même travail des événements divers de l’histoire militaire et diplomatique belge. Ainsi se détachent sur le « temps long » des constantes géopolitiques et géostratégiques liées à l’espace belge, à ses routes, chemins de fer et fortifications militaires. Les termini chronologiques choisis sont d’une part le traité des XXIV articles de 1839 et d’autre part le « Plan Schlieffen » (1905-1906). Néanmoins, pour des raisons d’unité, certaines thématiques débutent avant 1839 tandis que d’autres sont poursuivies jusqu’en 1914. C’est le cas de la problématique des nouvelles lignes de chemins de fer entre la Belgique, le Grand-Duché de Luxembourg et l’Allemagne, dont l’intérêt stratégique n’est pas évident si l’on choisit de s’arrêter arbitrairement à 1905. Pareillement, la problématique des plans du Génie belge pour interrompre les ponts de la Meuse et les tunnels ferroviaires en cas de conflit a été poursuivie jusqu’en 1914 pour conserver toute sa pertinence. En revanche, concernant l’étude des plans de guerre, la date de 1905-1906 a été privilégiée pour des raisons historiographiques justifiées dans notre introduction. Un des objectifs principaux de cette thèse est en effet de présenter et d’analyser l’évolution des plans français et prusso-allemands depuis 1839 dans leur relation avec la Belgique jusqu’au moment où l’on a dit admettre la violation de la neutralité belge comme un fait inéluctable. « Comment en est-on arrivé là ? », telle est la question à laquelle nous répondons. Sur le plan diplomatique, cette transition stratégique correspond aux débuts de l’Entente cordiale et à la conférence d’Algésiras, événements qui viennent complexifier la problématique du plan de guerre français par l’envoi hypothétique d’un corps expéditionnaire britannique appelé à opérer éventuellement en Belgique. En Allemagne, cette date charnière correspond à la retraite du général Alfred von Schlieffen. Un des autres aspects novateurs de cette thèse est d’étudier, parallèlement au processus d’élaboration des plans de guerre, l’évolution de l’infrastructure ferroviaire belge et de ses relations avec les pays limitrophes. Nous prouvons en définitive que l’évolution du réseau belgo-allemand, principalement dans la région Eifel/Ardennes, a eu une grande influence sur les plans d’Etat-major du début du 20e siècle. La fameuse « trouée du Luxembourg » les conduit à assumer progressivement le passage par la Belgique comme une future réalité de guerre. Enfin, malgré cette date charnière de 1905-1906, il nous a paru intéressant de problématiser ensuite dans un épilogue non exhaustif la question des plans français et allemands de l’immédiat avant-guerre, toujours en relation avec la traversée du territoire belge. Le chercheur y trouvera, nous le pensons, d’utiles pistes de réflexion pour des études ultérieures. [less ▲]

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See detailIngénierie génétique d'une β2-intégrine LFA-1 bovine résistante à la leucotoxine de Mannheimia haemolytica
Fett, Thomas ULg

Doctoral thesis (2012)

Domesticated bovines are known since decades to be prone to bacterial pneumonias. Among the causative agents, a consensus emerged stating that Mannheimia haemolytica is the most frequent bacterium ... [more ▼]

Domesticated bovines are known since decades to be prone to bacterial pneumonias. Among the causative agents, a consensus emerged stating that Mannheimia haemolytica is the most frequent bacterium isolated from bovine lungs throughout the world. Moreover, it appeared that its virulence specifically targets ruminant lungs in vivo and ruminant leucocytes in vitro. When the thesis was started, the two main actors underlying this species-specific virulence were known: the leukotoxin (LKT) on the pathogen side and the beta2-integrin LFA-1 on the host side. The objective of the thesis was to contribute to the understanding of the LKT/LFA 1 interaction at the molecular level. Using a between-species perspective, we showed that (i) the CD11a subunit of the LFA-1 heterodimer was not involved in the LKT-specificity for ruminant LFA-1, (ii) the EGF-3 module within the CD18 controls the susceptibility of any given CD18 to LKT and (iii) a non cleavable signal peptide conjugated to a LKT susceptible EGF-3-containing CD18 exacerbates LKT pronecrotic effects. [less ▲]

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See detailContribution à l'étude des propriétés tensioactives et membranaires d'esters dérivés de la glycine bétaïne
Nsimba Zakanda, Francis ULg

Doctoral thesis (2012)

The objective of this doctoral research is to contribute to the study of surface active and membrane properties of esters derived from glycine betaine. In this context, esters of glycine betaine ... [more ▼]

The objective of this doctoral research is to contribute to the study of surface active and membrane properties of esters derived from glycine betaine. In this context, esters of glycine betaine (alkylbétaïnate chlorides: CnBC, n = 10-16) were obtained using a new synthetic methodology. Glycine betaine (activated by thionyl chloride) and the primary fatty alcohols were used as basic raw materials for the chemical synthesis of CnBC. Some parameters to optimize the synthesis were studied, such as the nature of the organic solvent, the temperature, the molar ratio of reactants and the concentration of the latter in the reaction medium. Next, the surface active and membrane properties of CnBC were characterized using several instrumental techniques such as Langmuir film balance, isothermal titration calorimetry, fluorescence spectrometry and zeta potential and particle size measurements. Hexadécylbétaïnate chloride (C16BC) was synthesized with better performance under the following conditions: absence of a catalyst/base, a solvent of medium polarity (2-methyl-2-butanol), a temperature of 45°C, a molar ratio of betainyl chloride/1-hexadecanol of 3/1 and a concentration of reactants of 0.132 mol/L. Decylbetainate chloride (C10BC) dodecylbetainate chloride (C12BC) and tetradecylbetainate chloride (C14BC) were obtained using the optimal conditions for the synthesis of C16BC. Concerning the interfacial organization of CnBC, C10BC and C12BC did not form insoluble monolayers at the air-water at 20°C compared to their counterparts, C14BC and C16BC. The study of the monolayer of C16BC in various conditions of the aqueous subphase showed that the pH and monovalent anions (OHˉ, Brˉ, NO3ˉ, ClO4ˉ) did not influence the behavior of the monolayer compared to that in water with Clˉ as counterion while the temperature beyond 25°C, the divalent anions (HPO42-, SO42-) and the ionic strength of sodium sulfate (Na2SO4) affected it in term of interfacial area occupation of the molecules. Interactions between CnBC and model membranes have shown that in water, CnBC, regardless of the length of the alkyl chain, have highly penetreted into the negatively charged lipid monolayers (dipalmitoylphosphatidylserine and dipalmitoylphosphatidic acid), whereas their penetration was average and low into monolayers formed by lipids with small polar head (dipalmitoylphosphatidylethanolamine and cholesterol, CHOL) and lipid with large polar head (palmitoyloleoylphosphatidylcholine, POPC), respectively. In salted buffer, the adsorption of C16BC at the air-water interface and onto the surfaces of the lipid monolayers was instantaneous, and in all cases, the penetrating power was above the presumed pressure of biological membranes. C16BC formed miscible and stable mixtures with POPC and sphingomyelin while an almost ideal behavior was observed for its mixtures with CHOL. An affinity of C16BC for the membrane bilayer containing CHOL was also observed. The adsorption of CnBC onto the surfaces of bilayers was alkyl chain-dependent. C10BC, C14BC and C16BC did not significantly perturbed membranes even at high surfactant concnetrations compared to C12BC that has highly perturbed membranes without solubilizing them. In all cases, particles of positive charge and larger than those of membrane bilayers prepared were formed in the presence of high amounts of CnBC. [less ▲]

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See detailContribution à l'étude de la surveillance de la mécanique ventilatoire du nouveau-né ventilé.
RIGO, Vincent ULg

Doctoral thesis (2012)

Mechanical ventilation, still a major intervention to improve prognosis in newborns, requires careful monitoring of ventilated infants. This monitoring integrates different parameters. Its classical focus ... [more ▼]

Mechanical ventilation, still a major intervention to improve prognosis in newborns, requires careful monitoring of ventilated infants. This monitoring integrates different parameters. Its classical focus is on blood gases and their proxy (pulse oxymetry, transcutaneous oxygen and carbon dioxide content), and also includes physical assessment, thoracic imaging and appraisal of ventilator settings. Use of currently available on-line respiratory mechanics (RM) as displayed by ventilators seems limited given a large apparent variability. As current respiratory support strategies aim to reduce exposure to mechanical ventilation and to decrease ventilator associated lung injuries, additional continuous monitoring tools could benefit neonatal patients. In a review of advanced biomedical devices in use in the neonatal intensive care units and areas where improvement or evaluation is necessary, the National Institute for Child Health and Human Development underlines simple tools for continuous assessment of vital pulmonary functions at the bedside. This research aims at finding solutions to that problem. In a first step, different respiratory mechanics parameters (dynamic compliance –Cdyn, dynamic resistance –Rdyn, tidal volume –VT and the overdistension parameter C20/C) are obtained from ventilatory recordings of newborns under respiratory support with the most commonly used neonatal ventilator to evaluate their clinical relevance. Those data present a high variability and therefore lack precision. It is possible to mathematically decrease this variability by using parameters averaged over a few minutes and to obtain reproducible results. Continuous pressure, flow and volume data from the ventilator allow construction of pressure-volume, pressure-flow and flow-volume loops. From those loops, Cdyn, Rdyn and VT can be computed by the Mead-Whittenberger method. Those values when derived from respiratory cycles with good appearance significantly differ from ventilator values. Given the lack of precision of ventilator derived respiratory mechanics data, a new strategy is developed to obtain those parameters only from optimal looking respiratory cycles. A new software is designed to reconstruct waves and loops from the ventilator continuous recordings. This software individualises respiratory cycles and compute Cdyn and Rdyn (least mean square method), VT and C20/C. Using 10 sets of two recordings (one in Synchronized Intermittent Mandatory Ventilation and one in Assist/Control ventilatory modes), visual evaluation of 11274 respiratory cycles selects 4847 cycles considered optimal looking. Those assisted cycles present no or minimal leak, good hysteresis of the pressure-volume loop, and no abnormalities of the flow curves. The coefficients of variation of the respiratory mechanics parameters obtained with this method are significantly decreased, by 25-27% from the ventilator values for Rdyn, Cdyn and C20/C, and by 60% for VT. This increase in parameters precision is associated with an improved capacity to discriminate different values. Analysis of discordant values between ventilator and optimal respiratory cycles is relevant. In A/C mode, the VTs from the selected respiratory cycles are lower than values reported by the ventilator, suggesting that currently available VTs give incomplete information for adjustment of ventilator settings. In SIMV mode, the weak correlation between Cdyn from both methods leads to question the relevance of ventilator informations. The important scattering of ventilator C20/Cs out of classical values, and the absence of correlation with values from selected respiratory cycles demonstrate the lack of validity of ventilator C20/Cs. Overall, the results suggest that the use of data derived from selected respiratory cycles could underlie the conception of RM monitoring tools to support ventilatory management. To avoid the heavy workload associated with visual respiratory cycles’ selection, the software is improved to automatically identify optimal cycles. The positive predictive values and specificity of this selection are high. Respiratory mechanics parameters from cycles selected automatically are very concordant with those from visually selected cycles. The last step of this work assesses the software potential with analysis of 21 recordings from various clinical situations. The discriminating power of automatically selected respiratory cycles’ parameters is tested in an extended population. Trending abilities of those parameters are evaluated. Analyses of respiratory mechanics parameters derived from automatically selected cycles are able to demonstrate differences of 4.6-7.1% and more between parameters from two 10min recordings. Averaging data over 3-7min allows to determine a 10% difference. Parameters averaged over 10min allow detection of 10% changes in most patients. Those results should allow building trend curves with clinically and statistically significant informations. In conclusion, the continuous respiratory mechanics analysis software developed and evaluated in this work should give precise informations on the dynamic evolution of RM parameters. Functions integrated in the last version of the software give immediate research opportunities, and should lead to clinical application in a very near future. Those parameters could then complete current informations integrated in ventilatory management. [less ▲]

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See detailLes jeunes Belges francophones et le génocide des Juifs. Les enseignements d’une perspective de socialisation politique
Grandjean, Geoffrey ULg

Doctoral thesis (2012)

La mémoire du génocide des Juifs est encore vivace dans nos sociétés contemporaines. Ce fait passé apparaît fréquemment dans l’actualité au rythme des commémorations régulièrement organisées. Mais que ... [more ▼]

La mémoire du génocide des Juifs est encore vivace dans nos sociétés contemporaines. Ce fait passé apparaît fréquemment dans l’actualité au rythme des commémorations régulièrement organisées. Mais que peut-il signifier aujourd’hui pour de jeunes générations qui en prennent connaissance à l’école, en famille, par la visite de lieux de mémoire ou encore par de multiples œuvres cinématographiques ? Les impacts de ces connaissances sont ainsi très peu étudiés, notamment en termes d’apprentissage d’attitudes et de comportements politiques chez des jeunes amenés à devenir les citoyens de demain. En s’inscrivant dans le champ de la socialisation politique, l’objectif de cette étude est justement d’analyser les conséquences de ces connaissances. Pour ce faire, de jeunes Belges francophones ont été rencontrés dans le cadre de groupes de discussion. L’analyse des échanges montre que ces jeunes ont tenu différentes expressions sociales et politiques à partir de discussions portant uniquement sur le génocide des Juifs. En soulignant l’importance du souvenir, en témoignant de multiples émotions et en mobilisant toute une série de valeurs, ils ont envisagé la transmission de ce fait passé. Par ailleurs, leurs connaissances et leurs perceptions de l’univers politique ainsi que la façon dont ils envisagent leur participation politique interrogent leur rapport au pouvoir politique. En explorant l’univers mental des jeunes à partir de la thématique du génocide des Juifs, leur prise de conscience des cheminements politiques conduisant à un tel fait est mise en perspective. C’est aussi l’éventualité de sa répétition ou encore l’effacement de sa mémoire dans la dynamique des générations qui est mis en questions et en débats. [less ▲]

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See detailDirect imaging, photometry and spectroscopy of gravitationally lensed quasars
Ricci, Davide ULg

Doctoral thesis (2012)

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See detailEsthétique, affectivité et réflexivité. Essai sur la dimension interculturelle de l'anthropologie existentielle de Jean-Paul Sartre
Nke, Fridolin ULg

Doctoral thesis (2012)

Using existential anthropology in understanding contemporary history I try to reveal the value of the Sartrean model of intentional consciousness in understanding the human relationships and the political ... [more ▼]

Using existential anthropology in understanding contemporary history I try to reveal the value of the Sartrean model of intentional consciousness in understanding the human relationships and the political conflicts of our time. I examine the cultural aspects of Sartre’s thought. Sartre’s existential anthropology of the historical real-life refers to a complex philosophical method inspired by Husserl’s phenomenology, Freud’s psychoanalysis and Marx’s dialectic. It aims at understanding individual’s imaginary and behavior. Using that method, not only are we able to reveal the structure of people’s intentions in building and defending their personal and national interests, but also can we manifest the imaginary that constitute what Sartre designates by Dog’s mind, that meant criminal’s and racist’s beliefs. Sartre used his method in understanding writers as Baudelaire, Flaubert or Genet, who was also a criminal. Our intention is to apply psycho-analysis in understanding great figures of human history, such as Hitler, the “Dog” of our time, so that we shall be able to built harmless intercultural relationships. [less ▲]

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See detailÉvaluation de l’impact de l’extrapolation de bioréacteur sur la physiologie de Yarrowia lipolytica pour la production de lipase
Kar, Tambi ULg

Doctoral thesis (2012)

Les travaux entrepris au cours de cette thèse visent à mettre en place une méthodologie globale d’extrapolation de bioréacteurs. Le procédé de production de lipase par Yarrowia lipolytica a été plus ... [more ▼]

Les travaux entrepris au cours de cette thèse visent à mettre en place une méthodologie globale d’extrapolation de bioréacteurs. Le procédé de production de lipase par Yarrowia lipolytica a été plus particulièrement investigué, compte tenu de la complexité du système biologique et des paramètres physico-chimiques mis en œuvre. En effet, ce procédé met en œuvre une levure dite non conventionnelle dans un réacteur multiphasique G-L-L comprenant un substrat hydrophobe (le méthyloléate étant utilisé comme source de carbone renouvelable). Du fait du caractère strictement aérobie de ce type de levure, le transfert d’oxygène est un paramètre critique pour ce procédé. Dans un premier temps, l’ensemble des paramètres physico-chimiques clés du procédé ont été investigués (c’est-à-dire la dispersion du méthyloléate, les fluctuations en oxygène dissous et en pH). Cette évaluation a été menée en se basant sur des paramètres physico-chimiques (mélange du réacteur, transfert d’oxygène,…), mais également sur base de paramètres biologiques (synthèse et excrétion de la lipase, activation du gène lip2,…). Cette première étude a démontré que le paramètre critique était la fluctuation de l’oxygène dissous, ce paramètre menant à une réduction du rendement spécifique en lipase, liée à une atténuation de l’activité du gène lip2 codant pour la lipase extracellulaire de Y. lipolytica. Ce paramètre est d’autant plus important que les amplitudes des fluctuations en oxygène dissous sont amplifiées lors du processus de montée en échelle pour l’extrapolation du procédé. L’efficacité de dispersion du substrat hydrophobe (méthyloléate) au sein du milieu aqueux ne semble pas avoir d’impact sur l’efficacité du procédé, la levure sécrétant un biosurfactant permettant de stabiliser la dispersion. Les fluctuations en pH ont également peu d’impact sur le rendement de production de lipase, mais des observations au microscope ont révélé un début de dimorphisme cellulaire. Cette observation démontre la complexité de la réponse du système biologique face aux conditions de procédé. L’impact des fluctuations en oxygène dissous sur l’activité du gène lip2 a été confirmé par des analyses plus poussées en PCR quantitative (RT-qPCR). La deuxième partie du travail a donc été focalisée sur l’optimisation du transfert d’oxygène. Cette optimisation n’est pas triviale si on considère le phénomène de formation de mousse important lorsque la dispersion G-L au sein du réacteur est trop fine. Deux stratégies antimousse ont donc été envisagées : l’une mettant en œuvre l’ajout d’antimousse chimique et l’autre l’emploi d’un briseur de mousse mécanique. Cette dernière méthode s’est révélée inefficace du fait de la formation d’une couche de mousse persistante entre la surface du liquide et la turbine du briseur de mousse. Des analyses en cytométrie en flux ont permis d’observer un phénomène de dimorphisme qui semble lié au passage des cellules microbiennes au travers de cette couche de mousse, ce qui diminue le rendement en lipase. L’ajout d’antimousse chimique a donc été retenu et le transfert d’oxygène a pu être optimisé en fonction de contraintes de formation de mousse en considérant un enrichissement progressif de l’air d’entrée en oxygène pur. La dernière partie du travail a consisté à estimer l’extrapolation du procédé en prenant en compte à la fois les contraintes physico-chimiques du système (optimisation du transfert d’oxygène et limitation de la formation de mousse), ainsi que les contraintes biologiques. Cette extrapolation a tout d’abord été estimée au niveau de réacteurs scale-down permettant de reproduire les défauts d’écoulement généralement rencontrés au niveau industriel. De manière surprenante, cette étude a démontré que suite à l’adaptation physiologique des micro-organismes aux conditions d’écoulement, les problèmes de formation de mousse étaient de moins en moins marqués au cours de la montée en échelle du procédé. Cette observation va à l’encontre des calculs du génie chimique qui prédisent une augmentation du volume de mousse généré suite à la montée en volume des bioréacteurs et a été validée au niveau d’un bioréacteur pilote de 500L. Cela nous mène à conclure que la présence d’hétérogénéités au sein du volume réactionnel ne doit pas forcément être considérée comme un facteur négatif et pourrait au contraire être exploitée afin d’améliorer les performances des procédés et le design des bioréacteurs. [less ▲]

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See detailStructuration de la diversité génétique du genre Milicia: taxonomie, phylogéographie, dynamique des populations
Daïnou, Kasso ULg

Doctoral thesis (2012)

Characterizing population genetic structure using phylogeographic approach contributes to understanding of evolutionary processes that affect plant populations. The present study investigated how past ... [more ▼]

Characterizing population genetic structure using phylogeographic approach contributes to understanding of evolutionary processes that affect plant populations. The present study investigated how past environmental variations can shape the spatial genetic diversity of an African timber tree species, Milicia excelsa (Welw) C.C. Berg. Given that plant responses to disturbances are closely linked to life history traits, this research also aimed to describe relationships between the reproductive traits of M. excelsa and its population genetic structure. Phylogeographic analyses were performed throughout the range of M. excelsa using nuclear and chloroplastic markers. Ecological characterization was conducted for a single population located in south-East Cameroon. Since M. excelsa is similar to the other species of its genus, M. regia (A. Chev) C.C. Berg, we first performed a morphogenetic comparison of these two taxa. The results confirmed an important morphological similarity between the two species with very rare discriminating criteria. In fact Bayesian assignment methods and reproductive isolation patterns suggest the occurrence of interspecific hybridization, which appeared to be unidirectional: hybrids displayed the M. regia morphotype. Because M. regia is known to be more adapted to humid tropical forests, one may expect it to occur in the Congo basin zone. However, its range is restricted to the western part of West Africa while M. excelsa occurs from Guinea-Conakry to Zimbabwe. Interestingly, in the case of M. excelsa, Central and West African specimens had no shared haplotype. This result was unexpected because long gene dispersal distances were found in Cameroonian populations, as expected from the behaviours of the main dispersal animals we identified, the bat Eidolon helvum and the parrots Psittacus erithacus and Agapornis swindernianus. In general, despite the likelihood for long distance seed dispersal, distinct genetic clusters were identified over West and Central Africa and their location may support the forest refugia hypothesis. In addition a phylogeographical signal was detected in chloroplast DNA indicating a prolonged separation between West and Central Africa populations with an accumulation of new mutations. At a smaller spatial scale, patterns of genetic structure also seemed to be weakly influenced by divergent reproduction times among sympatric individuals. The level of genetic diversity in the study populations falls within the range of values calculated for other tropical tree species. If phylogeography helps to infer population history, it also requires ecological or biological information to confirm some uncertainties. Such detailed data were often lacking to completely interpret numerous of our results. The present study raised new questions and led to new perspectives for further investigation both in phylogeography and botany. [less ▲]

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See detailEtude de l'autofloculation dans un Chenal Algal à Haut Rendement (CAHR)
Baya, Dehenould Guy ULg

Doctoral thesis (2012)

Dans la technique du Chenal Algal à Haut Rendement (CAHR), l’effluent récupéré est très riche en microalgues. Les caractéristiques particulières de ce système (faible profondeur, faible temps de séjour ... [more ▼]

Dans la technique du Chenal Algal à Haut Rendement (CAHR), l’effluent récupéré est très riche en microalgues. Les caractéristiques particulières de ce système (faible profondeur, faible temps de séjour, agitation mécanique) combinées avec la présence d’ions inorganiques dans l’effluent sont les principaux éléments qui favorisent le développement intensif d’algues. Le rejet d’un tel effluent sans récupération préalable des microalgues est nuisible aux ressources biologiques terrestres et aquatiques et, plus généralement à l’ensemble des écosystèmes naturels. Par ailleurs, les microalgues peuvent être valorisées à des fins alimentaires ou d’extraction de sous-produits à valeur ajoutée. De plus, la récupération de la biomasse algale permettrait la réutilisation possible de la fraction liquide en irrigation notamment. Dans ce contexte, la récolte de la biomasse algale issue du CAHR constitue un enjeu majeur. Cependant, la petite taille des microalgues, la faible densité et les concentrations limitées rencontrées dans le CAHR comparées à celles de bioréacteurs industriels soulèvent un problème de rentabilité économique pour leur récupération en raison des énormes volumes d’eau à traiter. Les techniques usuelles de récupération de ces biomasses (en particulier par centrifugation) ont des coûts prohibitifs vis-à-vis de la valeur des produits récupérés. Dans ce cadre l’autofloculation qui est définie comme la formation et le rassemblement spontané de microalgues se présente comme une alternative aux problèmes rencontrés par les techniques conventionnelles de récupération des algues. C’est dans cette dynamique de recherche de s’inscrit cette thèse dont l’objectif est de déterminer les mécanismes impliqués dans l’autofloculation ainsi que les conditions optimales nécessaires à la réalisation de ce phénomène. Ce document est divisé en six grands chapitres : Les deux premiers chapitres sont consacrés à une revue des connaissances sur CAHR et la biomasse algale se développant dans ce système d’épuration. Également, un état de l’art concernant les méthodes de récolte de la biomasse algale notamment l’autofloculation est réalisé. Les simulations réalisées dans le chapitre III grâce à notre modèle thermodynamique de calcul de l’indice de saturation (IS) de différents composés mettent en évidence que les phosphates de calcium et formes substituées (Octacalcium phosphate, Ca4H(PO4)3; phosphate de calcium amorphe, Ca3(PO4)2; Hydroxyapatite, Ca5(PO4)3(OH); fluoroapatite, Ca5(PO4)3F et chloroapatite, Ca5(PO4)3Cl) sont les principaux composés inorganiques susceptibles d’être impliqués dans l’autofloculation. Le chapitre IV est consacré à la caractérisation des charges de surface, du potentiel zêta et des points isoélectriques de quelques phosphates de calcium et de la biomasse algale qui se développe dans le CAHR. Ces trois caractéristiques ont été déterminées respectivement par titrage colloïdal, par la méthode électrophorétique et par la méthode de Park et Regalbuto (1995) (détermination du pH d’équilibre à charge élevée). Cette étude a permis de conclure que la neutralisation des charges de surface des algues par les phosphates de calcium est probablement un moteur de l’autofloculation. Dans le chapitre V, des essais d’autofloculation simulée sur une biomasse provenant du CAHR et d’un milieu de culture ont été réalisés. Cette étude a essentiellement porté sur la détermination des concentrations optimales en ions calciums et orthophosphates, mais également sur la détermination des rapports de masse et de charge optimum entre les phosphates de calcium et algues pour une floculation maximale de la biomasse. Les résultats obtenus démontrent que les rendements d’autofloculation simulée sont très sensibles aux variations des concentrations en Ca2+ et PO43- et qu’il est indispensable de déterminer les concentrations optimales en ions calciums et orthophosphates pour obtenir les rendements maximums. En outre, les résultats permettent également de conclure que la neutralisation des charges des algues par les phosphates de calcium (purs ou substitués) se fait avec une stœchiométrie 1:1. Les doses de floculant nécessaires sont donc liées à la charge et peuvent être déterminées a priori sur cette base. Enfin, le chapitre VI porte sur le suivi expérimental de l’évolution de la biomasse algale dans une installation pilote et une installation réelle de traitement d’effluents par culture de microalgues installées au campus d’Arlon (eaux usées synthétiques) et Marrakech (eaux usées domestiques prétraitées). Les paramètres physiques, chimiques et biologiques ont été investigués, suivant les variations des conditions du milieu. Les résultats obtenus démontrent que l’installation de l’autofloculation entraine une déstabilisation du CAHR et une réduction de l’activité photosynthétique des algues. Ainsi, nous avons à notre disposition pour une eau de composition donnée, les outils pour prévoir la quantité d’algues qui pourra être récupérée sans ajouts de réactifs, encore faut il pouvoir gérer le réacteur pour atteindre ces conditions dans un délai court. [less ▲]

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See detailIsolation and identification of antioxidant phytochemicals from Cuban species of the genera Erythroxylum P. Browne and Pluchea Cass
Perera Cordova, Wilmer ULg

Doctoral thesis (2012)

Phytochemicals showing antioxidant properties are largely recognized as beneficial to human health and disease prevention. Cuba is well known for having a rich flora with a high percentage of endemic ... [more ▼]

Phytochemicals showing antioxidant properties are largely recognized as beneficial to human health and disease prevention. Cuba is well known for having a rich flora with a high percentage of endemic species; it is considered as an interesting source of plant species for searching bioactive metabolites. Polar and non-polar extracts were prepared by fractionation from macerations in ethanol: H2O (7:3 v/v) from several Cuban plant species. The antioxidant capacity and the concentration in phenolic compounds were assayed in these extracts. The native species Pluchea carolinensis (Jacq.) G. Don., Pluchea odorata (L.) Cass. and Pluchea rosea Godfrey were identified as the most promising sources of antioxidants. The n-butanol extracts obtained by reflux from endemic Erythroxylum alaternifolium A. Rich. var. alaternifolium, var. parvifolium and suborbiculare also displayed high antioxidant capacity and high levels in phenolic compounds. The antioxidant capacity and the phenolic content of hydroalcoholic macerations from leaves, inflorescences, stems and roots of species of the genus Pluchea were also compared. Leaf extracts followed by inflorescence extracts showed the highest values of antioxidant capacity. The species P. carolinensis was used as a model to evaluate the antioxidant capacity in two locations and two phenological stages and also for monitoring the antioxidant capacity over some months. Natural adult specimens presented a higher phenolic content, as well as higher antioxidant capacity than young and cultivated specimens. Maximal antioxidant capacity and concentrations in phenolics were recorded in January, September and December; over the blooming stage (March), the antioxidant capacity was minimal. Two different solvents of extraction and two methods were also screened for extracting the maximal concentrations in antioxidants. Hydroalcoholic extractions showed higher antioxidant capacity than ethanolic ones. However, no difference in antioxidant capacity were measured between the two methods of extraction. The antioxidant capacity of P. carolinensis was also measured in leaves of plantlets micro-propagated on three different in vitro culture media and it was compared with leaves of young specimens grown ex-vitro. The inclusion of a cytokinin in culture media increased the antioxidant capacity of the leaf extracts of plantlets grown in vitro. However, the antioxidant capacity of plantlets grown in vitro was lower than that of young specimens grown ex-vitro. Additionally, several phenolic compounds were isolated from the species studied. Two flavonol glycosides were isolated from n-butanol leaf extract of Erythroxylum alaternifolium var. alaternifolium. Moreover, 22 phenolic compounds (including 9 phenolic acids and 13 flavonoids) were also identified from leaf, inflorescence and stem extracts of the three Pluchea species. All of them are reported for the first time in Cuban Pluchea species. In addition, rosmarinic acid, ferulic acid, quercetagetin, herbacetin, quercitrin, eupalitin and 3-methyl-quercetagetin were described for the first time in the genus Pluchea. The antioxidant capacity of each of these compounds was evaluated. The results suggested that most of these phytochemicals have an important contribution to the antioxidant capacity found in plant extracts. [less ▲]

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See detailEtude des mécanismes cellulaires et moléculaires à l'origine du phénomène des DOMS (Delayed-Onset Muscle Soreness) consécutif à l'exercice excentrique.
Hody, Stéphanie ULg

Doctoral thesis (2012)

Tous, nous avons déjà ressenti diverses sensations de courbatures après avoir réalisé un exercice musculaire intense et/ou inhabituel. Ces douleurs musculaires d’apparition retardée et d’intensité ... [more ▼]

Tous, nous avons déjà ressenti diverses sensations de courbatures après avoir réalisé un exercice musculaire intense et/ou inhabituel. Ces douleurs musculaires d’apparition retardée et d’intensité variable sont désignées scientifiquement par l’acronyme « DOMS » pour « Delayed-Onset Muscle Soreness ». Le rôle particulier du mode de contraction excentrique dans la survenue des DOMS est largement accepté. Rappelons que l’exercice excentrique est caractérisé par l’association paradoxale des phénomènes opposés d’allongement musculo-tendineux et de développement tensionnel. Dès lors, les contraintes mécaniques accompagnant les contractions excentriques peuvent entraîner diverses altérations de l’ultrastructure musculaire qui se manifestent par une série de symptômes cliniques rendant les DOMS invalidants sur le plan fonctionnel. Or, le caractère discriminant de l’évaluation excentrique et l’efficacité rééducative de l’exercice excentrique dans plusieurs types de pathologies de l’appareil locomoteur ont formellement été démontrées. Dans ces conditions et bien qu’elles disparaissent spontanément après quelques jours de récupération, les DOMS retardent fréquemment la mise en route de programmes de réadaptation ou d’entraînement sportif. Actuellement, à l’analyse de la littérature, on ne peut que constater l’absence de solution thérapeutique susceptible d’atténuer significativement l’intensité des DOMS et de leurs conséquences fonctionnelles associées. Paradoxalement, l’exercice excentrique lui-même, lorsqu’il est proposé en conditions sous-maximales progressivement intensifiées, semble constituer la seule prévention réellement efficace, capable de prévenir l’apparition des DOMS. Malgré la littérature abondante consacrée à la description du phénomène des DOMS, aucune théorie unifiée n’est actuellement disponible pour expliquer la survenue différée des sensations douloureuses et les signes associés. L’efficacité d’un entraînement spécifique dans la prévention des DOMS a été confirmée par de nombreux travaux mais la nature de cet effet protecteur reste sujette à conjectures. Ce travail vise à une meilleure connaissance des mécanismes cellulaires et moléculaires impliqués dans le phénomène des DOMS survenant après la réalisation d’un exercice excentrique. Au cours de ce travail, nous avons donc tenté de contribuer à répondre aux questions suivantes : (1) Quels sont les corrélats biochimiques correspondants à l’apparition des DOMS suite à l’exécution d’exercices excentriques ? (2) Quels sont les mécanismes responsables de la variabilité interindividuelle des réponses à l’exercice excentrique ? (3) Quelles sont les adaptations induites par l’entraînement excentrique permettant de prévenir l’apparition des DOMS ? L’originalité de notre travail réside dans la mise au point d’un protocole expérimental chez l’humain associant la provocation de DOMS au moyen d’un dynamomètre isocinétique, le prélèvement de tissus musculaires humains par biopsie à l’aiguille et l’analyse protéomique comparative de ceux-ci par la méthode du 2D-DIGE. Nos travaux suggèrent qu’une plus grande sensibilité aux microlésions induites par l’exercice excentrique s’expliquerait par une prédominance de fibres rapides de type glycolytique et qu’un entraînement excentrique visant à prévenir les DOMS induirait une transition des fibres rapides de type glycolytique vers des fibres plus oxydatives. Le modèle humain, utilisé dans ce travail, nous a également permis de définir des indices de fatigue permettant de prédire l’ampleur de la réponse de la CK et de suggérer l’existence d’un effet protecteur controlatéral. Toutefois, les limites de l’expérimentation humaine ne nous permettent pas d’envisager une « manipulation » du système expérimental. Si on veut dépasser le stade expérimental d’observation encore possible chez l’humain et aborder le stade de stimulation et/ou d’invalidation par exemple, le recours à un modèle animal s’impose de lui-même. [less ▲]

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See detailTotal Electron Content reconstruction using triple frequency GNSS signals
Spits, Justine ULg

Doctoral thesis (2012)

Nowadays, Global Navigation Satellite System (GNSS) provide accurate three dimensional positioning and navigation anywhere and anytime on the Earth’s surface and are being utilized in numerous civilian ... [more ▼]

Nowadays, Global Navigation Satellite System (GNSS) provide accurate three dimensional positioning and navigation anywhere and anytime on the Earth’s surface and are being utilized in numerous civilian and military applications. The US Global Positioning System (GPS) is currently being modernized to transmit radio signals on an additional third frequency, while the European Galileo is a newly developed system which will transmit on three civil frequency bands. One of the major error sources affecting GNSS is the delay caused when the signals pass through the ionosphere on their way to the Earth’s surface. This delay is inversely proportional to the square of the carrier frequency, and directly proportional to the Total Electron Content (TEC) of the ionosphere. In the last 20 years, several techniques using dual frequency GNSS measurements have been developed to estimate the TEC. With these techniques, systematic errors are confined to at least - 2.5 and 2.5 TECU for a mid-latitude site, and to at least - 5.5 and 5 TECU for a low-latitude location. In the last decades, knowledge about the ionosphere has grown considerably thanks to the use of GNSS measurements, and in turn the GNSS have highly benefited from this improved knowledge. Nowadays the availability of triple frequency GNSS signals enables the development of new processing techniques. We have therefore dedicated this work to developing a TEC reconstruction methodology based on triple frequency GNSS measurements and aimed at improving the accuracy of the final TEC values with regards to existing techniques. The structure of this study is as follows. Firstly, we provide information about GNSS, focusing on concepts, definitions and assumptions which will be used throughout this study. Then, we introduce the concepts of ionospheric propagation of radio signals and give a review of the literature on existing techniques used to extract the TEC with dual frequency GNSS measurements. We further present the complete design of the triple frequency TEC reconstruction methodology. We start by giving the set of combinations which allows us to resolve the original integer ambiguities, then we address the principles of TEC reconstruction, and finally we give an accuracy assessment of the computed TEC values. We also present an innovative technique to calibrate the satellite and receiver code hardware delays. We continue with testing the features developed on a simulated GPS and Galileo observation dataset, as well as on a real GIOVE observation dataset. Finally, we conclude this work by providing a critical overview of our investigations and suggesting various improvements of the current limitations. [less ▲]

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See detailIdentification of Pythium species inducing common bean (Phaseolus vulgaris L.) root rot symptoms and development of backcrosses to improve the level of varietal resistance to this disease
Nzungize Rusagara, John ULg

Doctoral thesis (2012)

The common bean (Phaseolus vulgaris L.) is the most important food legume grown worldwide. It is a prioritary crop in various countries of East Africa and is grown mainly by small farmers for home ... [more ▼]

The common bean (Phaseolus vulgaris L.) is the most important food legume grown worldwide. It is a prioritary crop in various countries of East Africa and is grown mainly by small farmers for home consumption, the excess being sold in markets. Important yield losses of common bean induced by root rot diseases have been identified in several countries in East Africa including Rwanda. This is partly explained by the intensification of the cultivation of beans, the absence of rotations, the practice of continuous cultivation of this legume, and decline in soil fertility. Although bean root rot symptoms are caused by a number of soil borne pathogens depending on environmental conditions, Pythium spp. are the fungal pathogens most frequently associated with severe epidemics in eastern Africa. Studies on root rot have indicated that continuous cropping of beans, a common practice in eastern Africa, exacerbates the problem. This work was undertaken to improve the varietal resistance of common bean to limit the damages caused by Pythium in Rwanda. An analysis of the diversity of Pythium species associated with root rot was conducted through collect of samples of common bean plants throughout the country and through the characterization of the Pythium species causing root rot. The collected samples were used to isolate 96 typical Pythium colonies which were classified into 16 Pythium species according to their respective molecular sequences of the ribosomal ITS fragments. Molecular characterization using the ITS-DNA sequences was also carried out on samples isolated on infected beans roots. The study of the distribution of each species identified within the samples analyzed, revealed that Pythium vexans is the most widespread taxon in the different common bean producing areas in Rwanda. Pathogenicity tests of the 16 identified Pythium species were performed on a set of 10 common bean varieties. The results showed that all identified Pythium species were pathogenic to common bean: they all induce symptoms of root rot under controlled conditions. However, the common bean varieties used in this investigation showed differences in their reaction to inoculation with the 16 Pythium species. At the end of this work of the characterization of Pythium species isolated in Rwanda, a scheme for improving varietal resistance has been implemented. It is based on a backcross protocol assisted by molecular marker (PYAA 19800). Recurrent parents are composed of three common bean varieties traditionally grown in Rwanda while the two donor parents are a resistant variety of the Mesoamerican gene pool and a resistant variety of Andean pool. The progeny obtained after the backcrossing program was subjected to the pathogenicity trials by inoculating with a strain of Pythium ultimum in controlled conditions in order to verify the effectiveness of this improvement protocol. These trials have shown that in the offspring all the individuals showing the presence of the marker gene were also resistant to Pythium with very low levels of severity at the end of inoculation tests. [less ▲]

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See detailGouverner la maternité au Bénin. Les difficiles conditions d'application des politiques sanitaires dans le territoire de la Pendjari
Sambiéni, N'Koué Emmanuel ULg

Doctoral thesis (2012)

La Zone Sanitaire de Tanguiéta, partie intégrante du système de santé au Bénin, expérimente, depuis la décentralisation de ce système, la gestion autonome de l’offre de soins de santé moderne dans toutes ... [more ▼]

La Zone Sanitaire de Tanguiéta, partie intégrante du système de santé au Bénin, expérimente, depuis la décentralisation de ce système, la gestion autonome de l’offre de soins de santé moderne dans toutes ses dimensions. Elle est particulièrement ingénieuse dans la production d’initiatives de soins au profit des mères engagées dans l’enfantement, avec le soutien de l’Etat et des partenaires du secteur de la santé. Cet engagement est justifié officiellement par la situation critique des indicateurs de Santé Maternelle traduisant une morbidité et une mortalité élevées. La ZST est tout d’abord un espace socioculturel d’une particularité remarquable, comparée au reste du pays, du fait même de sa position géographique, de son identité culturelle pendjarienne et de son histoire sociopolitique. C’est de son identité socioculturelle et sociopolitique qu’elle revendique son autonomie technico-administrative dans la fourniture des soins de santé. La curiosité intellectuelle de cette recherche socioanthropologique est de comprendre comment la demande et les soins aux femmes qui « veulent donner la vie » sont véritablement « structurés » et « gouvernés » dans cet espace socioculturel et médical. « Habitus maternel » et « gouvernementalité» sont utilisés à la fois comme concepts et comme postures méthodologiques et épistémologiques afin de décrypter et d’analyser « l’ordre » et « le progrès » dans ces logiques et pratiques obstétricales. Suivant une méthodologie essentiellement qualitative, la recherche a duré quatre ans, avec une longue présence sur le terrain, consistant en des observations dans les maternités et dans les familles ainsi que des entretiens avec les différents acteurs participant aux soins. Cette recherche nous apprend que dans l’ordre traditionnel, l’enfantement a été historiquement et socialement géré par des institutions laissant une place assez faible à l’expression de l’individu, qu’il soit le père ou la mère de l’enfant en construction bio-sociale. A l’heure actuelle, les maternités modernes ont toujours du mal à prendre le pas sur ces institutions dans le contrôle des soins avant, pendant et après l’accouchement. Malheureusement, affaiblies par les différentes influences sociales, ces institutions apparaissent socialement et techniquement incapables de contenir et de régler le mal de la grossesse et de l’accouchement. La maternité, tant dans son état traditionnel que moderne, demeure encore morbide et mortelle. L’Etat et ses institutions d’encadrement et d’offre de soins maternels, peu connectés aux réalités socioculturelles, s’avèrent constamment dépendants des agences des Nations Unies et des autres partenaires privés, producteurs de stratégies le plus souvent d’ordre idéologique et militant. La Stratégie Nationale de Réduction de la Mortalité Maternelle et Néonatale et l’Initiative Femme pour Femme, respectivement élaborées au Ministère de la Santé et au niveau de la Zone Sanitaire, révèlent le rendez-vous manqué dans la rencontre programmée entre usagers des maternités et offre de soins dans la planification sanitaire. La maternité, avec ses multiples acteurs en négociation permanente sans consensus, est conflictuelle et souvent détournée de sa mission. Elle empile régulièrement des stratégies tout en chassant constamment ses premiers bénéficiaires et en mettant les enjeux sanitaires en arrière-plan. Pour une « Maternité Sans Risques » dans les espaces traditionnel et moderne, il faudra chercher et comprendre comment, dans la nébuleuse des institutions qui les gèrent dans ces deux registres, les femmes peuvent renforcer leurs positions légitimes dans la négociation pour l’orientation des soins obstétricaux essentiels et d’urgence. Il conviendra enfin d’étudier les conditions pour une lecture effective du risque obstétrical dans l’environnement social des femmes. [less ▲]

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See detailMachine learning-based feature ranking: Statistical interpretation and gene network inference
Huynh-Thu, Vân Anh ULg

Doctoral thesis (2012)

Machine learning techniques, and in particular supervised learning methods, are nowadays widely used in bioinformatics. Two prominent applications that we target specifically in this thesis are biomarker ... [more ▼]

Machine learning techniques, and in particular supervised learning methods, are nowadays widely used in bioinformatics. Two prominent applications that we target specifically in this thesis are biomarker discovery and regulatory network inference. These two problems are commonly addressed through the use of feature ranking methods that order the input features of a supervised learning problem from the most to the less relevant for predicting the output. This thesis presents, on the one hand, methodological contributions around machine learning-based feature ranking techniques and on the other hand, more applicative contributions on gene regulatory network inference. Our methodological contributions focus on the problem of selecting truly relevant features from machine learning-based feature rankings. Unlike the p-values returned by univariate tests, relevance scores derived from machine learning techniques to rank the features are usually not statistically interpretable. This lack of interpretability makes the identification of the truly relevant features among the top-ranked ones a very difficult task and hence prevents the wide adoption of these methods by practitioners. Our first contribution in this field concerns a procedure, based on permutation tests, that estimates for each subset of top-ranked features the probability for that subset to contain at least one irrelevant feature (called CER for "conditional error rate"). As a second contribution, we performed a large-scale evaluation of several, existing or novel, procedures, including our CER method, that all replace the original relevance scores with measures that can be interpreted in a statistical way. These procedures, which were assessed on several artificial and real datasets, differ greatly in terms of computing times and the tradeoff they achieve in terms of false positives and false negatives. Our experiments also clearly highlight that using model performance as a criterion for feature selection is often counter-productive. The problem of gene regulatory network inference can be formulated as several feature selection problems, each one aiming at discovering the regulators of one target gene. Within this family of methods, we developed the GENIE3 algorithm that exploits feature rankings derived from tree-based ensemble methods to infer gene networks from steady-state gene expression data. In a second step, we derived two extensions of GENIE3 that aim to infer regulatory networks from other types of data. The first extension exploits expression data provided by time course experiments, while the second extension is related to genetical genomics datasets, which contain expression data together with information about genetic markers. GENIE3 was best performer in the DREAM4 In Silico Multifactorial challenge in 2009 and in the DREAM5 Network Inference challenge in 2010, and its extensions perform very well compared to other methods on several artificial datasets. [less ▲]

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See detailDynamique associative et réduction de la pauvreté rurale: une étude comparative de villages inégalement couverts par des Organisations Non Gouvernementales dans la province du Bandundu et dans l’hinterland de Kinshasa.
Nganda Afumba, Jean Pierre ULg

Doctoral thesis (2012)

Comme bon nombre de pays en développement, la République Démocratique du Congo observe, depuis le début des années 90, un développement sans précédent du mouvement associatif, particulièrement des ... [more ▼]

Comme bon nombre de pays en développement, la République Démocratique du Congo observe, depuis le début des années 90, un développement sans précédent du mouvement associatif, particulièrement des organisations non gouvernementales de développement. Dans un environnement où les pouvoirs publics sont quasi inexistants, ces dernières sont considérées par certains comme des instruments efficaces de réduction de la pauvreté, et par d’autres comme des opportunistes évoluant aux dépens de la misère des gens. La présente recherche se propose de faire une étude comparative entre, d’une part, des ménages de deux villages de l’hinterland de Kinshasa largement couverts par des ONG, et d’autre part, des ménages de deux autres villages dans le Bandundu ne bénéficiant d’aucune intervention d’ONG. Cette étude a pour but la compréhension, l’analyse et l’appréciation empirique de la pertinence de la stratégie de développement et de réduction de la pauvreté rurale orientée vers la promotion des organisations associatives du type ONG, et in fine suggère un outil susceptible d’améliorer les interventions visant la réduction de la pauvreté rurale. [less ▲]

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See detailContribution à l’identification de l’agent étiologique de l’entéropathie épizootique du lapin
Huybens, Nathalie ULg

Doctoral thesis (2012)

Epizootic rabbit enteropathy (ERE) is a pathology of the digestive system inducing economic loss in rabbit husbandry throughout Europe. The aetiological agent is unknown at the present time but a ... [more ▼]

Epizootic rabbit enteropathy (ERE) is a pathology of the digestive system inducing economic loss in rabbit husbandry throughout Europe. The aetiological agent is unknown at the present time but a reference inoculum (TEC4) reproduces the pathology. This inoculum contains an extremely rich bacterial flora. Several methods were used to reduce this bacterial flora while retaining virulence: centrifugation on discontinuous sucrose gradient, cellular adherence and treatment with chloroform/ethanol, antibiotics and an acid buffer. The flora of the obtained fractions were analyzed using traditional bacteriological techniques: identification of cultivable species, counting of colony forming units (CFU) and direct bacterioscopic exam after Gram coloration. Then, molecular biology was used to compare inocula, fractions and negative control. Three methods were used to find sequences present in virulent inocula and absent from non virulent inocula and negative controls. Twenty-two restriction enzymes were used to compare the 16SrDNA restriction profile (Amplified Ribosomal DNA Restriction Analysis or ARDRA). Hypervariable regions V3 and V6 to V8 were studied by Denaturating Gradient Gel Electrophoresis (DGGE). Finally, Random Amplification of Polymorphic DNA (RAPD) was used on the inocula, fractions and negative controls. Only the RAPD allow the obtainment of sequences specific to virulent inoculum. Unfortunately, a study on field samples did not confirm the link between the sequences and ERE. For one of the two identified sequences, a bacterial strain carrier was isolated. The strain was inoculated into rabbits but no clinical signs of ERE were observed. Samples of stools, blood and serum were collected during an experimental ERE infection. The evolution of fecal bacterial flora was studied using DGGE to follow the evolution of flora over the course of the disease. Unfortunately, neither specific bands nor specific band patterns appeared to be linked to the disease. Seven bacterial species were detected in the blood samples of three inoculated rabbits at day two post inoculation, confirming the hypothesis that bacteriemia occurs early on ERE infection. Finally, six fractions were analysed by pyrosequencing of the 16SrDNA gene. The aim was to find one or several species present in the virulent inocula but absent or less numerous in the nonvirulent inocula and control. The richness and diversity of all the inocula is equal or superior to human feces. As expected, the flora identified by pyrosequencing was different from the cultivable flora. However, no genera or species was specifically linked to the virulent inocula. The resolution of this technique was inadequate to identify the aetiological agent of ERE. A higher number of samples and sequences could at best restrain the identification to one genus. [less ▲]

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See detailEssays on the complex relationships between Innovation and Performance in service firms, with particular reference to financial services: An intellectual capital perspective
Mention, Anne-Laure ULg

Doctoral thesis (2012)

Service sector firms have long been neglected in innovation studies despite their increasing importance for economy. However, recent research has revealed that service firms do innovate although they ... [more ▼]

Service sector firms have long been neglected in innovation studies despite their increasing importance for economy. However, recent research has revealed that service firms do innovate although they follow distinct paths and reach different outcomes than those of the manufacturing sector. Measuring the effects of innovation on performance has thus become an essential concern for both policy‐makers and business leaders. This dissertation specifically contributes to the current debate on the effects of innovation on performance at firm‐level in the service sector by shedding more light on the characteristics of these complex relationships and by defining its underlying mechanisms. For these purposes, an intellectual capital perspective is adopted. This dissertation first takes a broad sector approach to services, focusing on potentially innovative core service activities, and relying on the concept of relational capital, it explores the most commonly reported feature of innovation in services, which is the openness of the innovation process. As prior research indicates that there is a diversity of innovation patterns in services, the dissertation then concentrates on financial service firms. Besides their own significance, financial firms play a critical role in the proper functioning of the entire economy. Focusing on this specific industry, the dissertation further delineates the innovation process into its constitutive elements, referring to human, structural and relational capital concepts. The setting for most of the empirical studies is Luxembourg, which allows benefitting from the peculiarities of this small, open, international but highly innovative economy dominated by service firms. This dissertation mainly concludes that adopting an open strategy for innovation activities brings differentiated results according to the partners involved, with some contrast observed between market, science and competitor co‐operation. When examining how resources mobilized in the innovation process interact to affect performance in financial services, the dominant role of relational capital emerges. Furthermore, the examination unveils the interaction effects between the constitutive elements of intellectual capital and confirms the importance of the orientation towards innovation, in its various facets, in financial firms. Overall, this dissertation shows that adopting an intellectual capital perspective to understand the innovation process, to reveal its main ingredients and to disentangle its effects on performance can be insightful. [less ▲]

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See detailPracticing local culture as a vehicle of integration? Creative collaborations and Brussels’ Zinneke Parade.
Costanzo, Joseph ULg

Doctoral thesis (2012)

Immigrant integration, and socio-economic cohesion more broadly, continue to be top priorities at many levels of governance in Europe and are long-standing fixtures of scholarly, political and public ... [more ▼]

Immigrant integration, and socio-economic cohesion more broadly, continue to be top priorities at many levels of governance in Europe and are long-standing fixtures of scholarly, political and public debate across Europe and North America. Although integration and culture have been dominant themes in contemporary European and American social science and humanities literatures, their intersections—particularly involving immigrant participation in local arts and cultural activities—remain understudied. Through the use of mixed-methods research, my doctoral thesis addresses how participating in such creative activities serves as a vehicle for integration. This topic is examined within the context of the European capital city-region of Brussels, and provokes further inquiry into the role of place in integration and identity-making particularly within a context in which there is no universal or normative local identity. With the onsite support of local experts, artistic and cultural actors and the public at large, I examine the ‘creative collaboration’ of Zinneke Parade 2010—a biennial socio-cultural and urban project with origins in the Brussels 2000 European Capital of Culture Programme (ECoC). Though politicians and community organizers frequently cite Zinneke as an exemplary project of the Brussels-Capital Region, to date, no formal study has been conducted neither into its role in bridging many of the city’s socio-linguistic, spatial and economic divides nor into its role as a source for building local networks, social, cultural, economic or otherwise. Finally, this work is unique in its treatment of migrant and ethnic minority identity representations in an explicitly non-ethno-cultural event. In its biennial parade, Zinneke purposefully does not re-present separate ethno-cultural pasts, but instead reflects the identities of collective and creative efforts of today’s local Bruxellois. Fielded throughout 2010 and early 2011, in-depth interviews, combined with short as well as detailed questionnaires, form the basis of data which I have collected to answer the question: Does practicing local culture facilitate integration? [less ▲]

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See detailAssessing the impacts of technical and structure choices on groundwater model performance using a complex synthetic case
Wildemeersch, Samuel ULg

Doctoral thesis (2012)

According to the European Water Framework Directive (2000/60/EC) and the specific Groundwater Directive (2006/188/EC), Member States have to manage groundwater at the groundwater body scale and in an ... [more ▼]

According to the European Water Framework Directive (2000/60/EC) and the specific Groundwater Directive (2006/188/EC), Member States have to manage groundwater at the groundwater body scale and in an integrated way. Given the objectives of “good quantitative and qualitative status” of groundwater for 2015 stated by the Directive, end-users want to know the quantitative and qualitative evolution of groundwater for several scenarios. Physically-based and spatially-distributed groundwater flow and transport models constitute useful management tools in this context since they take explicitely into account the heterogeneity and the physical processes occuring in the subsurface for predicting system responses to future stress factors. However, at such a scale, groundwater flow and transport modelling is challenging due to (1) the complexity of geological and hydrogeological contexts, (2) the uneven level of characterisation knowledge, and (3) the representativity of measured parameters. Furthermore, such models require long execution times. As a consequence, a series of choices and simplifications are made for dealing with these issues. Therefore, the outstanding question is to know whether endusers’expectations can be met in spite of such choices and simplifications. This work focuses on choices and simplifications related to spatial discretisation and saturation–pressure relations in the unsaturated one. The influence of stress factor time resolution is also tested. Considering this general context, the objective of the present work is to evaluate the influence of some model technical (spatial discretisation) and structure (saturation–pressure relations) uncertainties on model results, parameter sensitivities, and optimisation performance in order to provide guidelines for model development. This is performed using a synthetic case inspired by typical groundwater bodies of Wallonia (Belgium). This synthetic case is used for obtaining reference observations in terms of flow rates and hydraulic heads. These reference observations are then compared with their simulated equivalent produced by simplified models differing by their spatial discretisation, their saturation–pressure relations in the unsaturated zone, or the time resolution of their stress factors. The simplified models are then ranked using several performance criteria measuring the discrepancies between reference observations and their simulated equivalent. This ranking leads to guidelines for large-scale groundwater flow model development with respect to typical end-users’ expectations. Whatever the time resolution of stress factors, the quantitative and qualitative analyses performed indicate that coarsening horizontal spatial discretisation deteriorates mainly the simulation of flow rates, coarsening vertical spatial discretisation deteriorates mainly the simulation of hydraulic heads, and (over)simplifying saturation–pressure relations in the unsaturated zone significantly impair the simulation of both flow rates and hydraulic heads. Although optimisation can compensate for errors induced by model technical and structure uncertainties, the improvement of model fit is limited, especially for the coarsest models. Furthermore, with respect to end-users’ expectations, the weighted least-square objective function is not always the most relevant criteria for optimising models. Therefore, it is essential to use specific performance criteria for evaluating model performance depending on the objectives of the study. The ideal would be to develop an end-users objective function for including such performance criteria in the optimisation process and stop the optimisation process once performance criteria would have reached the values specified by the end-users with respect to the objectives of the study. [less ▲]

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See detailIdentification d'effecteurs de la signalisation Delta/Notch dans la différenciation des cellules endocrines du système digestif
Flasse, Lydie ULg

Doctoral thesis (2012)

Les cellules endocrines du système digestif incluent les cellules pancréatiques, regroupées en ilots de Langherhans et les cellules entéroendocrines, disséminées tout le long de l’épithélium du tube ... [more ▼]

Les cellules endocrines du système digestif incluent les cellules pancréatiques, regroupées en ilots de Langherhans et les cellules entéroendocrines, disséminées tout le long de l’épithélium du tube digestif. Un disfonctionnement de ces cellules peut être à l’origine de graves maladies, en conséquence les cellules endocrine du tractus digestif font l’objet de nombreuses études. Une connaissance précise du mode de fonctionnement mais aussi du développement et de la différenciation de ces cellules est requise afin de pouvoir élaborer de nouveaux traitements. Bien que ces deux populations de cellules endocrines soient situées dans des organes distincts, elles présentent de nombreuses similarités. Ces similitudes se retrouvent au niveau des hormones produites mais également au niveau des facteurs de transcription et des voies de signalisation impliquées dans le développement de ces cellules. La signalisation Notch joue un rôle primordial dans le contrôle de la différenciation des cellules endocrines pancréatiques et intestinales, chez la souris et le zebrafish. L’objectif de ce travail consiste à mieux comprendre les étapes précoces de la différenciation endocrine en recherchant des effecteurs de type ARP/ASCL de la voie de signalisation Delta/Notch, impliqués dans le développement endocrine du tractus digestif. Dans le pancréas, nous montrons que le facteur ascl1b est le premier marqueur pancréatique endocrine à apparaître. Ce facteur qui appartient à la famille des ASCL, est requis pour initier la différenciation de la lignée endocrine. Le facteur neurod1, appartenant à la famille des ARP, agit plus tardivement dans le développement de cette lignée afin de permettre le maintien du programme de différenciation endocrine. Nous démontrons que ces deux facteurs agissent séquentiellement dans les précurseurs endocrines pour promouvoir leur différenciation. La perte simultanée de ces deux facteurs conduit à l’absence totale de cellules endocrine. Dans le tractus gastro-intestinal, nous montrons que la signalisation Delta/Notch réprime le destin sécréteur en inhibant l’expression du facteur ascl1a. La présence de ce facteur est absolument requise pour la différenciation de l’ensemble des cellules sécrétrice. ascl1a est à la base de la cascade de facteur de transcription contrôlant la différenciation des cellules entéroendocrines. Nous montrons également que, dans cet organe, neurod1 régule la différenciation de certains types de cellules entéroendocrines. Parallèlement à cette étude des facteurs ARP/ASCL, nous avons mis en évidence la fonction d’un nouveau régulateur de la différenciation endocrine pancréatique: rfx6. Ce facteur est exclusivement exprimé dans la lignée endocrine chez le zebrafish. En l’absence de rfx6, les précurseurs endocrine sont bloqués dans leur différenciation et s’accumulent. Ce facteur est donc requis pour la différenciation terminale des précurseurs endocrines. [less ▲]

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See detailReal-time Simultaneous Modelling and Tracking of Articulated Objects
Declercq, Arnaud ULg

Doctoral thesis (2012)

In terms of capability, there is still a huge gap between the human visual system and existing computer vision algorithms. To achieve results of su cient quality, these algorithms are generally extremely ... [more ▼]

In terms of capability, there is still a huge gap between the human visual system and existing computer vision algorithms. To achieve results of su cient quality, these algorithms are generally extremely specialised in the task they have been designed for. All the knowledge available during their implementation is used to bias the output result and/or facilitate the initialisation of the system. This leads to increased robustness but a lower reusability of the code. In most cases, it also majorly limits the freedom of the user by constraining him to a limited set of possible interactions. In this thesis, we propose to go in the opposite direction by developing a general framework capable of both tracking and learning objects as complex as articulated objects. The robustness will be achieved by using one task to assist the other. The method should be completely unsupervised with no prior knowledge about the appearance or shape of the objects encountered (although, we decided to focus on rigid and articulated objects). With this framework, we hope to provide directions for a more di cult and distant goal: that of completely eliminating the time consuming prior design of object models in computer vision applications. This long term target will allow the reduction of the time and cost of implementing computer vision applications. It will also provide a larger freedom in the range of objects that can be used by the program. Our research focuses on three main aspects of this framework. The rst one is to create an object description e ective on a wide variety of complex objects and able to assist the object tracking while being learnt. The second is to provide both tracking and learning methods that can be executed simultaneously in real-time. This is particularly challenging for tracking when a large number of features are involved. Finally, our most challenging task and the core of this thesis, is to design robust tracking and learning solutions able to assist each other without creating counter-productive bias when one of them fails. [less ▲]

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See detailExperimental and Numerical Investigations of the Aeroelastic Stability of Bluff Structures
Andrianne, Thomas ULg

Doctoral thesis (2012)

The study of the dynamic interactions between the wind and civil engineering structures has become increasingly important over the last few decades. Most of these structures are aerodynamically "bluff ... [more ▼]

The study of the dynamic interactions between the wind and civil engineering structures has become increasingly important over the last few decades. Most of these structures are aerodynamically "bluff" and are becoming more flexible. Bluff-body aeroelasticity is a very challenging research area due to the unsteadiness and nonlinearity of the aerodynamic loading. This thesis presents the investigation of three aeroelastic phenomena affecting bluff-bodies: Vortex Induced Vibration (VIV), Galloping and Torsional Flutter. For each instability, extensive experimental studies are carried out in the wind tunnel. Innovative analysis, based on the Common-base Proper Orthogonal Decomposition (CPOD) method is used to study the flow visualization data. The VIV phenomenon is studied on a flexible tube with a circular cross-section, supported from its midpoint. A CPOD-based input-output model is developed to describe the system. The galloping instability is studied on a generic bridge section. A complete analysis of the aeroelastic behaviour of the structure is presented and a new polynomial empirical model is developed, which reflects accurately the nonlinear nature of the system. The torsional flutter phenomenon is extensively studied for two different structures: a generic bridge deck and a rectangular cylinder. The Motion Induced Vortex is identified as the fundamental cause of this aeroelastic phenomenon, on the basis of the analysis of the flow around the oscillating rectangle. In addition, it is demonstrated that the quasi-steady theory is not adapted to estimate the onset velocity of torsional flutter. Finally, a 2D aeroelastic simulation code, based on the Discrete Vortex Method (DVM) is developed. The non-linear aerodynamics around the body are well reproduced, allowing the simulation of all the aeroelastic instabilities investigated experimentally. [less ▲]

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See detailSpatial and temporal responses of marine gastropods and biofilms to urban wastewater pollution in a Mediterranean coastal area
Vermeulen, Simon ULg

Doctoral thesis (2012)

The increasing human pressure exerted along coastlines and the subsequent increase in the delivery of pollutants at sea is a matter of concern worldwide. Urban wastewaters contain a variety of pollutants ... [more ▼]

The increasing human pressure exerted along coastlines and the subsequent increase in the delivery of pollutants at sea is a matter of concern worldwide. Urban wastewaters contain a variety of pollutants (mainly N, P, and trace elements) which can be involved in the launching of eutrophication. This complex process is able to fundamentally alter the integrity of coastal ecosystems thereby impairing the sustainability of economic activities and involving health risks for human through the consumption of sea products. Eutrophication is considered for more than 40 years as a pervasive process and a priority issue for the preservation of the health status of coastal ecosystems. The Mediterranean Sea supports high economic pressures in relation with the continuously increasing number of inhabitants and tourists in coastal areas. The physico-chemical (e.g. oligotrophy, microtidal regime) features of waters make them sensitive to eutrophication and several heavily urbanized areas have been experiencing adverse effects of this process for decades (e.g. biodiversity losses, Harmful Algal Blooms, fishes’ kills,…etc). Nowadays, smaller localities discharging insufficiently treated or raw wastewaters at sea also begin to report eutrophication problems especially during summer months when the number of tourists considerably increases the resident populations. National monitoring programs generally focus on priority areas by using either toxicological (e.g. trace metals in molluscs) and / or structural (e.g. phytoplankton biomasses) parameters to follow the evolution of already impacted water bodies. However, if the most deleterious effects of eutrophication are well known, little information is actually available regarding the early symptoms of the process. The identification of time- and cost-efficient indicators along with analytical procedures that would deliver early warning signals of pollution is therefore required to assist local authorities in the implementation of environmental policies. This research aimed at implementing some easy-to-use and efficient tools to detect the impact of urban wastewater pollution in Mediterranean coastal areas. A new set of potential early bioindicators has been identified. The gastropods Patella caerulea and Monodonta turbinata inhabiting the Mediterranean rocky midlittoral zone and epilithic biofilms were selected as good candidates for monitoring purpose. Biofilms which are microbenthic communities mainly composed of microalgae have been used for decades in freshwater systems as early indicators of pollution. In contrast, marine biofilms have largely been neglected and little is known regarding their composition, their physiology, and the way they react to wastewater pollution. We focused our studies on the Calvi Bay (NW Mediterranean, France) which is, regarding the anthropogenic pressure exerted on its coastal fringe, representative of other moderately urbanized areas of the Mediterranean basin. The Calvi Bay area is indeed among the preferred summer destinations by tourists in Corsica and is influenced by a single point source of pollution which is secondary-treated urban wastewater. A control vs. impacted sites approach has been used to assess the responses of the selected bioindicators to wastewater pollution. Our first task was to characterize the nature and amounts of the main pollutants (nutrients, trace elements) discharged in the Calvi Bay. Since nutrient measurements are commonly used to infer into the trophic status of water bodies, we assessed whether this parameter was reliable to detect the influence of wastewater discharge in the study area. The main pollutants discharged at sea were ammonium, phosphorus and iron. Amounts considerably increased during summer months (July and August) which was related to the high frequentation of the Calvi Bay area by tourists. Measurements of nutrient concentrations in seawater samples from controls and impacted sites did not allow evidencing the influence of wastewater inputs. In contrast, the high spatial and temporal resolution achieved through a small scale sampling design conducted in a small harbour impacted by wastewater discharges showed large spatial variability in the dispersion of effluents and hourly variations in the amounts of pollutants. The extrapolation of these results at the scale of the Calvi Bay may have explained our failure to detect the pollution by using samples collected punctually in space and time. These results suggested that the use of bioindicators that integrate the variable influence of nutrient pulses was required to evidence pollution. We focused our second study on a toxicological approach to detect the bioavailability of anthropogenically-derived nutrients in the midlittoral zone of the Calvi Bay and of the Marseille harbour. Multi-spatial scales and seasonal dual C and N stable isotope analyses were performed on the limpet Patella caerulea, the snail Monodonta turbinata, epilithic biofilms, and the macroalga Rissoella verruculosa. All bioindicators exhibited strongly elevated δ15N values at impacted sites compared to pristine ones, which revealed the influence of wastewater pollution in the midlittoral zone and the biological availability of anthropogenically-derived nitrogen at the base of the food web. Gastropods provided a time-integrated response reflecting the control vs. impacted status of sites. Results indicated that one sampling campaign per year should be sufficient to evidence wastewater pollution likely because of the slow turnover rate of gastropods’ muscles. Macroalgae showed a reliable but less consistent signal of wastewater pollution compared to other indicators. Only epilithic biofilms tended to show the occurrence of nutrient pulses during the tourist season which suggested that wastewater discharges may have influenced the composition and / or the physiology of communities. However the sampling of biofilms developed on natural rocky substrates was destructive and did not allow investigating the fine biological structure of communities and thus to fully understand the output of community scale parameters such as stable isotopes. We therefore recommended using biofilms grown on artificial substrates to circumvent this problem. We then allowed biofilms to develop on glass slides which are the most currently used artificial substrates in freshwater systems. Our task was to find out the most suitable technique to isolate and identify benthic diatoms which are common colonizers on newly available substrates. The species-specific tolerance to pollution of diatoms has been used for decades in the assessment of the health status of freshwater bodies. However, little is known on their marine counterparts and on their ability to evidence wastewater pollution. A specific and time-cost-efficient technique was implemented for the processing of lightly silicified benthic marine diatoms from Mediterranean oligotrophic areas. This was achieved through the multiple comparisons of existing protocols used either in sea- or fresh-waters. We finally investigated, by means of mesocosm deployed in situ and field experiments, the responses of biofilms developed on glass slides to a range of urban wastewater exposures. Colonization experiments lasted for 24 days in summer conditions. A multi-parametric assessment was conducted using a combination of toxicological and structural approaches applied to different biological scales. Toxicological parameters such as C-N stable isotopes, C:N:P ratios, and Trace Elements were measured at the community scale while the structural parameters were considered at the community (standing crops), assemblage (densities of the main autotroph and heterotroph organisms), and the genus (diatoms) scales. The mesocosm experiments were highly efficient to demonstrate the good potential of biofilms as early indicators of wastewater pollution. The impact of wastewater pollution was mainly identified at the community and the genus (diatoms) scales. Standing crops and the C-N stable isotopes were the most useful parameters showing respectively a stimulation of microalgal biomasses (i.e. eutrophication) and the bioavailability of wastewater-derived nitrogen even at low pollution levels. At the genus scale, the composition of diatoms’ assemblages changed markedly especially in the most polluted mesocosms. Results notably highlighted the proliferation of the small-sized individuals of Entomoneis which was thought to outcompete the larger diatoms belonging to the genus Mastogloia for nutrient uptake. The responses of biofilms to pollution largely differed between mesocosm and field experiments. Nevertheless, standing crop parameters corroborated results obtained in mesocosms allowing to assume an influence of wastewater pollution in the Calvi Bay. Field samples were generally characterized by the presence of well developed hydrozoan colonies which were only seldom reported at mesocosm sites. The presumably impacted site also exhibited the highest densities in other heterotrophic eukaryote groups (e.g. nematodes, polychaetes, foraminifers) and primary producers. We interpreted these results either as a top-down effect or as an increase in habitat complexity. The genus scale determination of diatoms’ assemblages showed a decrease in the relative abundances of Mastogloia at the impacted site which was in accordance with results from the mesocosm experiments. The highest density values were also observed for Cylindrotheca at impacted site. The last part of this research gathers the multiple spatial and temporal responses provided by the selected bioindicators to urban wastewater pollution in order to validate their future routine use in the context of monitoring programs. The occurrence of potential confusion sources in the interpretation of data was critically reviewed. The time-cost-efficiency of the tested parameters was then evaluated in order to assist environmental managers in their choices of biofilm-based techniques for detecting wastewater pollution. Finally since biofilms exhibited some strong accumulations of toxic elements, ecological hypotheses dealing with the trophic role of biofilms and the transfer of pollutants through the food webs are provided. [less ▲]

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See detailNumerical schemes for tracer studies in shallow shelf seas
Mercier, Christophe ULg

Doctoral thesis (2012)

Nowadays, tracers have revealed to be an invaluable integrated tool to investigate the different thematics related to coastal areas, shallow shelf seas or estuaries. In this work, they are used in ... [more ▼]

Nowadays, tracers have revealed to be an invaluable integrated tool to investigate the different thematics related to coastal areas, shallow shelf seas or estuaries. In this work, they are used in combination with a parallel scalable Fortran90 implementation of a 3D hydrodynamic model to study the transport of mud within the Belgian Coastal Zone. The results obtained illustrate the need for tools to understand the interactions between such highly energetic coastal areas and the sediment dynamics. The Constituent Age and Residence time Theory (CART), originally applied to passive tracers, is therefore extended to describe the sediments and used to quantify their rates of resuspension and horizontal transport. This application reveals some numerical issues that may degrade the reliability of the results. The different numerical parameterizations are thus revisited starting with the use of advection schemes, and especially, the Total Variation Diminishing (TVD) schemes built along the line defined by Harten. It is shown that the blind application of the usual TVD schemes and associated flux limiters can lead to non-TVD solutions when applied to complex geometries. Spatial and/or temporal variations of the bathymetry can indeed break the TVD property. Hopefully, really TVD schemes can be recovered by taking these variations into account in the formulation of the flux limiters. Even if its Eulerian formulation eases the implementation of CART into existing models, it is shown that CART's computation procedure lacks a numerical framework for a robust application. To address this, we enforce the consistency, defined as the requirement that the integration scheme does not introduce errors in the age field when aging is the only active process. Unfortunately, this does not guarantee the absence of overshootings. While it does not seem feasible to ensure a TVD behavior of the age field, appropriate modifications of the flux/slope limiters are derived here to prevent the occurrence of age values outside the physically acceptable range. On the bases of the solutions obtained after the advection of any numbers of tracers using high-order non-linear schemes, several control or global variables can be built. Even if the independent advection schemes used are specifically built to produce profiles free from the numerical artifacts that can spoil the physical meaning of the results, such global/control variables can exhibit these unwanted behaviors. This problematic is firstly treated with regard to the TVD schemes built from Harten's theorem. But guaranteeing the TVD property is not always feasible. Alternatively, appropriate modifications of the flux/slope limiters are implemented here to enforce a maximum principle for any global/control variable built as first-order homographic function of its components. [less ▲]

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See detailRole of NF-κB p65 subunit phosphorylation by ATM in DNA damage-regulated gene expression
Sabatel, Hélène ULg

Doctoral thesis (2012)

DNA damage, induced by several genotoxic agents, challenge genome integrity. Among the different types of DNA lesions, DNA double-strand breaks (DSB) are the most deleterious. Indeed, if not correctly ... [more ▼]

DNA damage, induced by several genotoxic agents, challenge genome integrity. Among the different types of DNA lesions, DNA double-strand breaks (DSB) are the most deleterious. Indeed, if not correctly repaired, they can lead to cell death or carcinogenesis. Upon DSB, cells activate a complex signaling network, the DNA damage response (DDR), to counteract those threats. The DDR coordinates DSB repair, checkpoint activation, apoptosis and transcription factors regulation, including NF-κB.   NF-κB family is composed of 5 proteins (RelA/p65, RelB, c-Rel, p105/p50 and p100/p52) which assemble in dimers to form active NF-κB transcription factor. In resting cells, NF-κB complexes are bound to inhibitor proteins such as IκBα, and maintained inactive in the cytoplasm. Classical NF-κB activation requires activation of IκB kinase (IKK) complex, which phosphorylates IκBα, finally leading to its degradation. NF-κB transcription factor is then free to translocate to the nucleus where it regulates a wide array of target genes. NF-κB is an important regulator of diverse cellular processes, including immune response, inflammation, cell survival, proliferation, differentiation, adhesion and apoptosis. NF-κB activation is associated to several pathogenesis and especially contributes to the growth and malignancy of cancer cells. NF-κB also affects the tumor response to many types of chemotherapy and ionizing radiation. Therefore the understanding of the regulation mechanisms of this transcription factor represent a major concern.   This work was interested in the regulation mechanism of DSB-induced NF-κB via the direct phosphorylation of the NF-κB subunit p65 by ATM kinase, the main mediator protein of the DDR. Indeed, rapidly activated in response to DSB, this kinase phosporylates a huge amount of substrates involved in different cellular functions. It had been previously shown that ATM was required for DSB-induced NF-κB activation by acting at two levels. On the one hand, activated ATM phosphorylates the IKK regulatory subunit NEMO. On the other hand, ATM is important for TAK1 activation and TRAF6 poly-ubiquitination, two steps necessary for full IKK complex activation too. The present work therefore highlighted a third ATM-mediated NF-κB regulation mechanism. This study showed that following DNA damage, the phosphorylation of p65 on Ser547 by ATM lead to the lower expression of a set of specific genes mainly involved in inflammation. Phosphorylated p65 was shown to interact with the co-repressor HDAC1, leading to specific promoter deacetylation and subsequent decreased gene expression.   In a second time, we also showed for the first time the requirement of MDC1 protein in DNA damage-induced NF-κB activation. MDC1 protein is mainly described as playing an important role in DSB-induced nuclear foci, which consist in large protein structures that assemble at the site of the DSB. Nevertheless, it appeared in this study that the role of MDC1 in NF-κB activation pathway is foci-independent. [less ▲]

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See detailDiversity and endemism of Murinae rodents in Thai limestone karsts: a genetic approach
Latinne, Alice ULg

Doctoral thesis (2012)

Limestone karsts are characterized by an important species richness and high levels of endemic species of plants, vertebrates and invertebrates adapted to this extreme environment. However, in Southeast ... [more ▼]

Limestone karsts are characterized by an important species richness and high levels of endemic species of plants, vertebrates and invertebrates adapted to this extreme environment. However, in Southeast Asia, karst ecosystems suffer from a considerable lack of scientific data and remain widely unknown despite their high biological importance. Combining field investigations with phylogeographic and phylogenetic analyses based on several kinds of molecular markers, this thesis aims at exploring the diversity and endemism of Murinae rodents in limestone karsts of Thailand. Thai limestone karsts host two endemic Murinae rodent species, Leopoldamys neilli and Niviventer hinpoon. This thesis reveals that L. neilli is more largely distributed in Thailand than indicated by previous records available in the literature. The species has been recorded in numerous limestone karsts of Thailand with the exception of its peninsular area. L. neilli has also been discovered in central Laos. Moreover our niche modeling study indicates that large tracts of suitable habitat for this species may also occur in several regions of Indochina. L. neilli populations are highly fragmented and a deep genealogical divergence among its lineages is observed. Both mitochondrial and nuclear markers support a large-scale population structure of four main groups (west, centre, north and northeast) and a strong finer structure within each of these groups. These results indicate that L. neilli populations are isolated on karsts such as on islands and that migrations among them are reduced. Our findings also suggest that the current phylogeographic pattern of this species results from the fragmentation of a widespread ancestral population and that vicariance has played a significant role in the evolutionary history of L. neilli. These deep vicariant events that occurred during Plio-Pleistocene are related to the formation of the Central Plain of Thailand. Moreover, the western populations of L. neilli are genetically and morphologically highly divergent from the other populations and could represent a separate species. This strong phylogeographic pattern is not observed for other Murinae species with lower levels of ecological specialization such as Leopoldamys edwardsi and Rattus tanezumi. Finally, this thesis provides preliminary information about the diet of L. neilli and indicates that plants of the Solanaceae family constitute an important part of its diet. The phylogeographic structure of N. hinpoon is not similar to the one of L. neilli. In contrast to L. neilli, N. hinpoon is confined to central Thailand and mitochondrial markers used in this study indicated that this species is genetically homogenous and characterized by a single mitochondrial lineage. Valuable data to refine the conservation status of L. neilli and N. hinpoon, two species currently listed as Data Deficient on the IUCN Red List have been gathered during this study. Three main threats to the long-term subsistence of L. neilli have been identified: (1) the high fragmentation of its population, (2) the large-scale destruction of limestone karsts in Southeast Asia, and (3) the intense trapping of this species for human consumption in northeastern Thailand. Therefore we propose to consider L. neilli as “Near threatened” on the IUCN Red List. However, if the western lineage of L. neilli represents a separate species, it should be listed as “Vulnerable”. Due to its small distribution range and the high threats that its habitat is facing in central Thailand, N. hinpoon would also be qualified as “Vulnerable” on the IUCN Red List. In addition to karst endemic species, this thesis reveals that Thai limestone karsts host high levels of Murinae rodent diversity. A sequence-based species delimitation method completed by the analysis of the level of genetic divergence was used to define species boundaries within our rodent samples collected in limestone karsts. A total of 12 described Murinae species, corresponding to 17 putative species based on our genetic criteria, were encountered in limestone karsts of Thailand. Most of these species are associated to forest ecosystems. Therefore this study suggests that limestone karsts could play a key role in the preservation of the rodent biodiversity by providing refuges for the forest-dwelling Murinae rodents in deforested regions. An important cryptic diversity has been detected within the traditionally recognized species Maxomys surifer and Berylmys bowersi. They could be considered as species complex and require further taxonomic work. The potential distribution of Leopoldamys edwardsi and Leopoldamys sabanus, two species also distributed in Thailand, has been investigated using niche modeling techniques. The predicted distribution ranges of these two species suggest a clear geographical separation between them, with the potential distribution of L. edwardsi being limited to the northern part of Indochina while L. sabanus is mainly distributed in the Sundaic region. Our findings also suggest that these two species could have survived in large areas of Southeast Asia during Quaternary ice ages without large scale extinction and that no drastic modification of the distribution of these species will occur in the future due to climate changes. In conclusion, using various genetic approaches, this work gains important insights into the Murinae rodent diversity of Thai limestone karsts and represents the first detailed study of karst endemic rodent species in Southeast Asia. [less ▲]

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See detailExperimental study of the hydraulic behaviour of Piano Key Weirs
Machiels, Olivier ULg

Doctoral thesis (2012)

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See detailModélisation régionale des écoulements souterrains et du transport de nitrates dans le bassin de la Dyle amont
Cesar, Emilie ULg

Master's dissertation (2012)

Les objectifs principaux de cette étude visaient à, d’une part, recalibrer le modèle hydrogéologique d’écoulement préexistant du bassin de la Dyle amont en distribuant spatialement la recharge et, d’autre ... [more ▼]

Les objectifs principaux de cette étude visaient à, d’une part, recalibrer le modèle hydrogéologique d’écoulement préexistant du bassin de la Dyle amont en distribuant spatialement la recharge et, d’autre part, étudier la pollution diffuse en nitrates en considérant un flux massique associé aux eaux d’infiltration variant spatialement. Le modèle WetSpass a été utilisé pour calculer la recharge moyenne annuelle distribuée sur le bassin. La technique HFEMC implémentée dans code SUFT3D a été utilisée pour modéliser les écoulements souterrains et le transport de nitrates. La modélisation du transport de nitrates dans les eaux souterraines a été effectuée en considérant plusieurs scénarios simplifiés d’intrants, de 1950 à 2010. L’approche classique de détermination des écoulements a été combinée à la technique des « mixing cells » pour modéliser le transport de solutés. Ce travail a démontré la faisabilité de l’association, à l’échelle du bassin de la Dyle amont, du modèle WetSpass et du code SUFT3D pour la modélisation des écoulements souterrains et du transport de nitrates. [less ▲]

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See detailEtude de l’implication du microARN miR-146a dans
Halkein, Julie ULg

Doctoral thesis (2012)

La cardiomyopathie du péripartum (PPCM) est une maladie mortelle qui touche certaines femmes entre le dernier mois de la grossesse et jusqu’à 5 mois après l’accouchement. Ces femmes présentent des ... [more ▼]

La cardiomyopathie du péripartum (PPCM) est une maladie mortelle qui touche certaines femmes entre le dernier mois de la grossesse et jusqu’à 5 mois après l’accouchement. Ces femmes présentent des symptômes d’hypertension et un dysfonctionnemment du ventricule gauche. A la fois l’endothélium et les cardiomyocytes sont affectés dans le cœur des patientes atteintes de la PPCM et il a été récemment montré que le fragment de 16 kDa de la prolactine (PRL 16K) était un facteur majeur dans la pathophysiologie de la maladie. Dans notre laboratoire, nous travaillons depuis des années sur les mécanismes d’action de la PRL 16K. Nous nous intéressons également aux microARN (miARN), ces régulateurs de l’expression des gènes décrits pour être impliqués dans la plupart des processus physiologiques et pathologiques tels que l’angiogenèse ou les maladies cardiovasculaires. Ils sont également décrits depuis peu pour pouvoir être sécrétés par une cellule productrice et transférés à une cellule receveuse, via des microvésicules, afin d’y jouer un rôle. Au cours de ce travail, nous avons mis en évidence que la PRL 16K est capable d’induire l’expression de miR-146a au sein des cellules endothéliales via l’activation de NF-B et d’induire son transfert via des microvésicules appelées exosomes. Ces exosomes endothéliaux sont capable d’interagir avec les cardiomyocytes et le contenu en miR-146a y est transféré. Au sein des cellules endothéliales, miR-146a possède des propriétés anti-angiogènes. Il réprime la prolifération et favorise l’apoptose des cellules endothéliales. Parmi ses gènes cibles potentiels, nous validons NRAS via lequel miR-146a pourrait médier une partie de ses effets. Au sein des cardiomyocytes, nous avons mis en évidence un rôle de miR-146a dans la répression du métabolisme corrélé à une diminution de l’expression d’ErbB4. Nous avons ensuite montré le rôle central tenu par miR-146a dans un modèle murin de souris développant la PPCM. On retrouve dans le cœur de ces souris un niveau augmenté de miR-146a et un niveau diminué d’ErbB4 et de NRAS. De plus, l’inhibition de miR-146a dans ces souris PPCM, via l’injection d’oligonucléotides anti-sens, permet de restaurer le phénotype sain des souris PPCM. On observe une restauration de l’activité cardiaque ainsi qu’une normalisation des niveaux d’expression de miR-146a et de ses gènes cibles. Chez la femme présentant une PPCM, les niveaux cardiaques de miR-146a et d’ErbB4 sont également dérégulés. Ces résultats suggèrent que miR-146a tient un rôle central dans la pathophysiologie de la PPCM et permet d’expliquer la dualité d’action de la PRL 16K sur les cellules endothéliales et les cardiomyocytes. Enfin, les miARN extracellulaires présents dans le plasma constituent des biomarqueurs de choix pour le diagnostic d’un grand nombre de pathologies. Ainsi, nous avons mis en évidence un niveau d’expression plasmatique significativement plus élevé chez les patientes atteintes d’une PPCM comparé à celui de femmes saines ainsi que de patientes présentant également de l’insuffisance cardiaque dû à une cardiomyopathie dilatée. En conclusion, en plus d’être un facteur impliqué de façon centrale dans la pathophysiologie de la PPCM et constituant dès lors une cible thérapeutique intéressante, miR-146a permet un diagnostic spécifique de la maladie. [less ▲]

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See detailIntérêt du broutage des haies et bandes boisées pour les bovins sur parcours en Wallonie
Vandermeulen, Sophie ULg

Master's dissertation (2012)

The establishment of agri-environmental measures in Wallonia promotes hedges and woody strips planting in the agricultural landscape. This study aimed at evaluating the influence of trees and shrubs ... [more ▼]

The establishment of agri-environmental measures in Wallonia promotes hedges and woody strips planting in the agricultural landscape. This study aimed at evaluating the influence of trees and shrubs access on the feeding behaviour of grazing heifers and determining the feeding value of woody species. The second objective was to assess the anti-parasitical effect of these ligneous forages. For 4 consecutive weeks from April to May 2012, 12 dairy heifers were equally distributed among two different groups: one with an open access to a woody hedge (experimental group) and the other not (control group). The feeding behavior of heifers was recorded during days of 10 hours, in relation to the available herbaceous biomass. At the end of the experiment, a faeces analysis was used to assess the presence and the number of parasites infesting heifers. The leaves of 12 woody species harvested in late May 2012 were analyzed for their chemical composition and their in vitro ruminal fermentability using a gas test. The results were compared to those obtained for white clover and ryegrass. The feeding behavior of heifers was influenced by their access to woody species. Indeed, grazing time of control animals (59.8%) was superior to animals that could browse the hedge (54.8%). The experimental animals browsed the ligneous when the pasture herbaceous biomass was the lowest (0.22 kg DM/kgBW*ha), namely the second week of the experiment only. During this week, browsing time represented 3.72% of the time spent on pasture. Faeces parasites analysis showed a significantly lower infestation of trichostrongyles in experimental animals. The chemical composition and kinetic parameters of in vitro ruminal fermentation varied significantly among woody species. The CP content ranged from 14.3% in Viburnum opulus to 31.9% in Sambucus nigra. Fraxinus excelsior had a CP content of 24.5% and a maximum gas production of 120ml/gDM. These values were similar to the values obtained for ryegrass (26.4% CP and 132.2 ml /gDM). The highest maximum gas volume produced was reached for Populus nigra (135.5 ml /gDM) and was equivalent to ryegrass. In conclusion, in the grazing conditions in Wallonia, browsing can be considered as complementary feeding for cattle on pasture with hedges. Indeed, some woody species appear promising for livestock nutrition such as Sambucus nigra, Fraxinus excelsior or Populus nigra. This work is a preliminary study in the sylvopastoral area. Future studies should be explored to confirm the results obtained in this study and to deepen knowledge of this area. [less ▲]

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See detailNarration et jeu vidéo. Pour une exploration des univers fictionnels
Barnabé, Fanny ULg

Master's dissertation (2012)

This dissertation is devoted to the study of the various terms through which the video game as a medium can build a narrative. First of all, it is quite relevant to note that traditional narratologic ... [more ▼]

This dissertation is devoted to the study of the various terms through which the video game as a medium can build a narrative. First of all, it is quite relevant to note that traditional narratologic tools are not suitable to describe every aspect of video game narrativity. Indeed, contrary to what some researchers say, this medium does not necessarily limits itself to imitating literature and cinema in order to build a narrative (which would therefore consist merely of texts and cutscenes): it is also able to convey narrative information through purely ludic elements (a setting can reveal the past of a character, the interface can or cannot be integrated into the fiction etc.). Moreover, these "narrativisation elements" (as named by Sébastien Genvo ) make sense only when they are activated i.e. acknowledged by the video game player: the gamer’s attitude is therefore a variable which is to be taken account in the study of video game narrative. However, if the video game narrative only exists in the form of potentiality possibly updatable by the player, how could we define precisely a corpus that would set apart narrative games from those radically devoid of narrative? With what tangible elements could we study an object that varies according to the receiver who activates it? The reflexion of this work shows that these methodological difficulties cannot be solved thanks to the traditional narratology tools – unless distorting them until they become inoperative. The thesis sustained here consists of calling into question the validity of the notion of narrative (as a linear sequence of events) because this latter is neither able to render all the "narrativisation elements" nor the player’s influence on the narration. The notion of fiction world then stands in for the notion of narrative. This concept designates a particular form of narration, displayed on several dimensions and in which the linear narrative is one aspect among others. More precisely, the universe is divided into three key notions (borrowed from Etienne Armand Amato ): the cosmos, the diegesis and the ludiegesis. In order to test the effectiveness of this new conception of the narrative and to establish a first approach of the field through the new vision that it allows, this dissertation suggests to take an inventory and describe the main "narrativisation elements" that can occur in the construction of a diegesis. Forteen of these can be counted: the cutscenes, the texts, the avatar, the characters, the intertextual references, the paratext, the interface, the camera, the objects, the environment, the objectives, the sounds, the gameplay and the variations introduced by the player (the manipulation of the rules and the choices). The conception of the narration as a universe (i.e an arrangement of elements that the player has to organize into a hierarchy, and not a succession of events) permits to consider the possibility to "load" with narrative these different game levels and the consequences of this investment on the story which is vehicled this way. Moreover, this reformulation favors the acknowledgement of the player in the elaboration of the narrative, since it authorizes a new conception of the story, which no longer appears like a "whole to receive", but like an "area to explore". [less ▲]

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See detailDétermination du rôle de l'uPAR dans la signalisation du VEGF
Paques, Cécile ULg

Master's dissertation (2012)

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See detailDéveloppement d’un procédé biotechnologique de production de molécules à note verte à partir de feuilles de betterave
Gigot, Cédric ULg

Doctoral thesis (2011)

La grande richesse des feuilles de betterave en 13-HPL (entre 10 et 12 UE1/g de poids frais), une enzyme produisant le (3Z)-hexénol, le (2E)-hexénal et le n-hexanal, fait de ce substrat un candidat ... [more ▼]

La grande richesse des feuilles de betterave en 13-HPL (entre 10 et 12 UE1/g de poids frais), une enzyme produisant le (3Z)-hexénol, le (2E)-hexénal et le n-hexanal, fait de ce substrat un candidat potentiel pour le développement d’un procédé biotechnologique de production d’arômes alimentaires. Maillon essentiel du système de défense des plantes, l’enzyme 13-HPL est inductible par des stimuli externes et son expression dépend de l’âge et de l’état physiologique de la plante. Au cours de ce travail, l’optimisation de l’expression de cette enzyme au sein du végétal a été étudiée préalablement au développement d’un procédé industriel visant à exploiter ce substrat. Ce procédé comprend successivement quatre opérations chimiques : une hydrolyse d’huile végétale riche en acides gras insaturés, une oxydation de ces acides, un clivage par les 13-HPLs et une purification des aldéhydes et des alcools synthétisés. Selon nos résultats, l’étape limitante de ce procédé est la synthèse d’aldéhydes qui présente, dans des conditions optimales de réaction, une capacité de production maximale de 0,502mM à l’échelle pilote (100L). L’inhibition suicide par le substrat et l’instabilité combinée de l’enzyme et de ces produits de réaction réduisent le taux de clivage des aldéhydes. La mise au point d’un système d’extraction des arômes volatils par flux gazeux et d’une alimentation fedbatch en substrat permet de réduire l’impact limitant de ces facteurs et d’accroître la capacité de production à 1,37mM. Afin de mieux comprendre les mécanismes réactionnels, l’enzyme 13-HPL de la betterave a été séquencée et clonée dans un vecteur procaryote permettant de disposer d’une source d’activité enzymatique indépendante des contraintes du milieu extérieur. L’utilisation de ces techniques a permis de développer un procédé bivalent (à la fois de source microbienne et végétale) de production d’arôme exploitable au sein de l’industrie alimentaire. [less ▲]

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See detailÉvaluation du niveau de stress du cheval en compétition et en milieu hospitalier : Mesures comportementales, physiologiques et appréciation du tempérament
Peeters, Marie ULg

Doctoral thesis (2011)

Both in humans and in animals, stress is sometimes considered as useful for the accomplishment of certain tasks. But it might also have a negative influence on health, welfare or safety. We often impose ... [more ▼]

Both in humans and in animals, stress is sometimes considered as useful for the accomplishment of certain tasks. But it might also have a negative influence on health, welfare or safety. We often impose on our domestic horses a lifestyle very different from their natural one. As soon as we interact with this animal, either during manipulations or in competition, we face him to various stressors. This stress can affect their health, their well-being as well as their sportive performances. Horses’ stress might also lead to a lack of safety for people handling them (horsemen, riders, breeders, veterinarian,...). Stress can be assessed by various indirect ways. Among all responses possibly shown by horses submitted to a stressor, we mainly focused on behavioural responses and on a physiological response: changes in cortisol secretion. Our first goal was to validate the use of saliva for free cortisol level determination. Secondly, we used this technique to assess stress level of both horses and riders during equestrian competitions. We compared riders’ and horses’ stress levels and we examined the potential relationship between the stress levels and the competition performances. The results showed that cortisol levels significantly increased during competition, both in horses and riders. The best performances were achieved by riders with the smallest increase in cortisol during competition. And, more surprisingly, the best performances were achieved by horses with highest cortisol increase. In this study, stress of both partners seems to have an opposite influence on their performances during competition: positive effects for horses (‘eustress’) but negative effects for riders (‘distress’). It would be interesting to test these measurements under other competition conditions. We also have tested the relationship between the horse’s temperament (scored by the owner), the stress levels in competition and the obtained performances. It came out that a higher increase in cortisol is more related to some ‘excitement’ rather than anxiety, and was mainly found in curious, motivated and active horses. This stress follow-up in competition should improve the welfare of the horse and his rider, and should probably also enhance performances achieved by the pair. In clinical settings, we identified the stress-related behaviours, that use to lead to a low ‘easiness of manipulation’. We also tested the relationship between temperament assessed by the owners, by the clinic staff and the stress-related behaviours. More particularly, we observed a predictive effect of a simple test (weigh scale test) on the appearance of these stress-related behaviours. This test would allow clinicians to anticipate potential difficulties during examinations and to prevent deriving injuries. Improving the stress measurement techniques and horses’ temperament assessment is essential for domestic horse welfare studies, as they occur in hospital, during competition, or in other stressful situations. Using physiological stress measurements, as salivary cortisol, is very useful and more reliable if they are used in conjunction with ethological methods.  [less ▲]

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See detailLes pestivirus à l'interface faune sauvage-faune domestique: pathogénie chez l'isard gestant et épidémiologie dans la région Provence-Alpes-Côte d'Azur
Martin, Claire ULg

Doctoral thesis (2011)

Dans les Alpes du Sud de la France, des diminutions de populations de chamois (Rupicapra rupicapra) ont été rapportées. Or, depuis une dizaine d’année, des pestivirus ont causé de fortes mortalités dans ... [more ▼]

Dans les Alpes du Sud de la France, des diminutions de populations de chamois (Rupicapra rupicapra) ont été rapportées. Or, depuis une dizaine d’année, des pestivirus ont causé de fortes mortalités dans des populations d’isards des Pyrénées (Rupicapra pyrenaica). Bien que les signes cliniques associés à cette infection aient été caractérisés chez cette espèce, la pathogénie chez les animaux gestants est peu étudiée. De plus, des transmissions inter-espèces ont régulièrement été incriminées dans l’épidémiologie des pestiviroses ; ceci particulièrement au niveau des alpages où des contacts fréquents sont décrits entre ruminants sauvages et domestiques. Les objectifs de ce travail de thèse ont donc été, dans un premier temps, d’étudier la pathogénie de l’infection à pestivirus chez des isards et plus particulièrement ses effets sur la gestation. Dans un second temps, nous avons étudié l’épidémiologie de l’infection dans différentes zones de la région Provence-Alpes-Côte d’Azur (PACA), tout d’abord chez des ruminants sauvages, puis à l’interface entre les ruminants sauvages et domestiques partageant les mêmes alpages (...). [less ▲]

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See detailProcessus d'externalisation graphique dans les activités cognitives complexes : le cas de l’esquisse numérique en conception architecturale individuelle et collective
Safin, Stéphane ULg

Doctoral thesis (2011)

This thesis investigates the modalities of creating external representations in complex cognitive activities, especially graphical representations: the explanatory diagrams, annotations of documents or ... [more ▼]

This thesis investigates the modalities of creating external representations in complex cognitive activities, especially graphical representations: the explanatory diagrams, annotations of documents or drawings make it possible to formulate ideas, to synthesize information, to communicate and to reason. This work seeks to understand in depth the processes involved in graphic expression, and the impact of representation supports on this activity. For this purpose, it addresses the original concept of digital sketch in the field of architectural design. This concept aims to allow the architect to draw freehand sketches, in an entirely digital environment, but in a «natural» way, as with its traditional tools. The idea is to take advantage of the ease of use of the pen, while exploiting the capabilities of simulation or representation of the digital medium. The freehand sketch is indeed known as an essential tool for the design: thanks to its fluidity, its immediacy and the freedom it allows, it supports efficiently the creative phases of ideation. It is also a powerful tool for document annotation in collaborative design and project review. This work analyzes the interest and the contribution of digital sketching in architectural design, but also stresses the constraints it vehicles as an instrument of individual and collective thought. It also seeks to identify the impact of electronic pen as a mode of interaction on the cognitive and graphical activities in design tasks. This thesis is based on three original empirical studies on the use of digital sketching environments. It describes the logic of graphical externalization, compares the characteristics of digital and traditional sketches, identifies the cognitive functions of representations transformations and makes explicit the role of the graphical modality in collaborative remote design. [less ▲]

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See detailFirst-principles study of multiferroic materials : BiFeO3 and Bi2FeCrO6
Goffinet, Marco ULg

Doctoral thesis (2011)

The present work is devoted to an ab-initio characterization, using planewave and localized basis sets, of multiferroic and magnetoelectric materials. After a general description of the underlying ... [more ▼]

The present work is devoted to an ab-initio characterization, using planewave and localized basis sets, of multiferroic and magnetoelectric materials. After a general description of the underlying concepts and computational techniques, we focus on BiFeO3, which is probably the most intensively studied multiferroic. We start our investigation by comparing the ability of different exchange-correlation functionals (LSDA(+U), GGA and hybrid) to accurately describe the most fundamental properties of BiFeO3 (crystallographic structure, electronic band structure, magnetism, phonons at Gamma, Born effective charges). Next we present infrared reflectivity and Raman spectra obtained from first-principles and compare them to experimental data. We then extend the study of the dynamical properties of BiFeO3 to the whole Brillouin zone by analyzing the phonon band structure, density of states and interatomic force constants. We also use combined Einstein and Debye models to fit the specific heat as obtained from first-principles and compare it to experimental data. The final part of this thesis is devoted to the investigation of pressure driven spin phase transitions in Bi2FeCrO6 . [less ▲]

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See detailLand conversion for industrialization and its impacts on household livelihood strategies in Hung Yen province, northern Vietnam
Nguyen, Thi Dien ULg

Doctoral thesis (2011)

This thesis is about the impact of land conversion for industrialization on household livelihood strategies in Hung Yen province, northern Vietnam. The study shows that land conversion is generating a ... [more ▼]

This thesis is about the impact of land conversion for industrialization on household livelihood strategies in Hung Yen province, northern Vietnam. The study shows that land conversion is generating a household landholdings decline while boosting the land market. After land conversion, 16% of laborers in the surveyed households find employment in industrial factories while 52% find jobs in the informal sector. Because of land conversion, rather than being net food producers, peasant households have become net food purchasers. Meantime, food safety in industrial areas is threatened by increasing environmental pollution. The findings also demonstrate that 51.9% of the surveyed households choose diversification as a livelihood strategy while 35.6% of them shift entirely to non-farm strategies. Among the affected peasant groups, households with a non-farm background that lost less than 50% of their agricultural land are likely to be in a better position to engage in lucrative non-farm jobs. Land conversion is causing a complex agrarian transformation in Vietnam. On the one hand, it generates a mechanism of social differentiation which is determined by land alteration and capital accumulation from high earning non-farm activities. On the other hand, peasant livelihood strategies, thanks to adaptation and innovation, have mitigated the impacts of land conversion and reveal the persistence of a peasant economy. [less ▲]

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See detailLa médiation par les objets en design industriel - Perspectives pour l'ingénierie de conception
Elsen, Catherine ULg

Doctoral thesis (2011)

The preliminary ideation phase, determining more than 70 % of a project’s total costs, is a crucial part of the design process. It usually gathers several actors around the innovative solving process of a ... [more ▼]

The preliminary ideation phase, determining more than 70 % of a project’s total costs, is a crucial part of the design process. It usually gathers several actors around the innovative solving process of a complex problem : it merges their complementary expertise, the use of mediating objects as well as a mysterious part of creativity in order to reach a solution if not innovative, at least satisfactory. With the introduction of always more powerful Computer Aided Design tools, industrial design sees its every-day practices drastically evolving : these software still not support designers during their preliminary design phases and free-hand sketches, on the other hand, encounter increasing difficulties to meet today time-to-market pressures. This thesis analyzes free-hand sketches’ and CAD tools’ respective and complementary strengths as supports to preliminary design phases. Advanced design engineering concepts, nurturing the study of the particular articulation existing between both mediating objects, are associated with dedicated Human Factors methodologies for the analysis of every-day professional practices. The research project draws its main qualitative and quantitative results from three field studies and two experimentations, bringing together more than forty professional designers and three design companies. Its multi-disciplinary approach leads to models and recommendations that directly nurture the definition of a new design support system. The specifications tend to respect, augment or, on the contrary, reject some aspects of these mediating objects and aim at supporting a design process always in respect with designers’ constraints and real needs. Beyond the concepts of our support system, we discuss some results that are of interest for communities of design engineering and human-computer interaction. Among these results are : - the extension of the preliminary design phase’s boarders ; - the non-dichotomous approach of rough and detailed mediating objects ; - the coexistence of two design moves : in addition to Schön’s «see-transform-see» theory, the externalization of a strong mental image or a strong pre-inventive form explains the early uses of CAD tools ; - the study of tool’s uses and misuses and graphic and semantic contents of external representations all along the design process, reintroduced in a simplified four-steps model ; the study of shifts occurring between 2D and 3D representations and their implications for the system’s automatization ; - and, at the strokes’ scale, the study of the exploitable key-features and the strokes’ cycles and their implications for the temporality of assistance. The thesis also discusses the added-value of its theoretical and methodological background for the materialization of a design-engineering community that articulates designer, mediating objects, design process and end-users in a coherent system, sound basis for the specification of adapted and adopted design support systems. [less ▲]

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See detailAstrophysical parameters and multiplicity of massive stars: a mathematical approach
Mahy, Laurent ULg

Doctoral thesis (2011)

Often quoted for their crucial role in the ecology of galaxies, massive stars remain mysterious. The exact process leading to their formation, their stability or their stellar winds are so many questions ... [more ▼]

Often quoted for their crucial role in the ecology of galaxies, massive stars remain mysterious. The exact process leading to their formation, their stability or their stellar winds are so many questions which are still unanswered. Since the lifetime of these objects is too short to allow them to move far away from their birth places, the large majority of massive stars are located in young open clusters or in OB associations. The observations of massive stars in these locations thus provide with promising information on their formation mechanisms. One of the most interesting properties, in this context, is their multiplicity. Indeed, the proportion of multiple systems, the values of orbital periods, of eccentricities, or of mass ratios are parameters directly linked to the formation mechanism and to the dynamical interactions occurring during the earliest stages of their existence. Moreover, constraining this multiplicity with a sufficient accuracy allows to obtain a better determination of the nature and physical parameters of massive stars. The present work is devoted to the study of the O star populations located in the young open cluster NGC2244 and in the surrounding Mon OB2 association as well as in several OB associations of the Cygnus complex. We establish not only the multiplicity of about thirty stars but also their fundamental parameters such as their masses or their N content. However, the complexity of observed spectra of multiple systems makes these objects difficult to investigate. Their analysis thus requires the development and the utilization of mathematical tools such as the "disentangling" which allows to separate the spectra of the components from the observed ones or such as the Doppler tomography which aims at mapping the wind interactions seen in some binary systems. The first part of this dissertation is dedicated to the development and to the characterization of these mathematical methods whilst the second part focuses on the study of populations of massive stars. We refine the orbital and physical parameters of systems already known as multiple. In this context, the analysis of the two components of LZ Cep system reveals modified abundances for the secondary star, confirming a mass transfer from the secondary towards to primary. We also detect for the first time a third star in the HD150136 system. This object, composed of an O3, an O5.5 and an O6.5, constitutes a new test to apply these mathematical methods and thus to better constrain the physical properties of the system as well as those of each component. Moreover, we find, in the population of NGC2244, of Mon OB2 and of the Cygnus OB associations, six new binary systems and derive the orbital solutions for five of them. These results show that NGC2244 hosts only one long-period binary and none with a short period whilst four short-period and no long-period systems are detected in the Cygnus complex. This obvious lack of short-period system in NGC2244 contrasts with the O star populations in other young open clusters such as NGC6231 or IC 2944. Besides the multiplicity, the fundamental parameters such as the N content also allows us to, notably, adapt the so-called Hunter-diagram to galactic O stars. Moreover, we have obtained photometric data for six O-type stars in NGC2244 and Mon OB2 with the CoRoT satellite. These data of unprecedented quality allow us to detect the presence, in the O star light curves, of red noise which is supposed to originate from either the sub-surface convection zone, the granulation or an onset of clumping in the winds of the stars. We also highlight the existence of non-radial pulsations in the light curve of Plaskett’s Star as well as a hot spot located between the two components of that system. In addition, numerous frequencies, extracted from the CoRoT light curves, reveal, for some of the observed stars, solar-like oscillations or beta Cephei-like pulsations. This analysis thus gives a first observational constraint on the bright end of the massive star instability strip. [less ▲]

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See detailBeef cattle systems in the context of sustainable agriculture in Bac Kan province, the Northern Mountainous Region of Vietnam
Hoang, Thi Huong Tra ULg

Doctoral thesis (2011)

Among livestock types, beef cattle production is ranked as a very important sub-sector in the extremely harsh natural conditions characterising the northern uplands of Vietnam, where ethnic minorities are ... [more ▼]

Among livestock types, beef cattle production is ranked as a very important sub-sector in the extremely harsh natural conditions characterising the northern uplands of Vietnam, where ethnic minorities are often concentrated on land resources which are not hospitable to crops. To help local people to escape from poverty, many organisations have initiated development projects featuring beef cattle production, but it still remains under-developed, hence the generally high level of poverty faced by farmers. <br /> <br />Thus, the study aims to assess the characteristics and appropriateness of beef cattle feeding systems, which are compared from the point of view of sustainability. <br /> <br />Stratified sampling was used to select 97 households within free-range, part-time grazing, and cut-and-carry feeding systems, which were surveyed in Bac Kan province between 2007 and 2009. The collection of field data was implemented using various survey instruments such as structured questionnaires and interview guides. Data processing consisted in descriptive statistics, correlations between the variables, and the calculation of socio-economic indicators. Based on the sample surveyed, the differences between the three systems of cattle management were highlighted. <br /> <br />Access to grazing land and its topography, the ethnicity of the communities, the relative importance of agricultural and forest production, and opportunities for off-farm employment were all factors influencing the cattle systems. Those using the “cut-and-carry” fodder system are practicing the most efficient husbandry style among the systems from both the social and economic points of view, except for lack of proper management and use of cattle manure. Manure use for cultivation in this system was limited because of the predominantly steep slope lands and the habits of the indigenous peoples. Animal manure utility was evaluated as less important in the cut-and-carry system compared to other systems practiced in the lowlands. <br /> <br />However, good prospects are seen to improve conditions in the rural uplands in the future. Thus, different strategies should be implemented to fill the gap and improve the position of farmers. The study derives helpful recommendations for farmers keeping beef cattle to strongly develop their production, alleviate poverty, and improve their livelihoods. [less ▲]

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See detailauditory sensitivity in birds: sex differences and noise impacts
Noirot, Isabelle ULg

Doctoral thesis (2011)

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See detailSynthèse, mise en forme et frittage de céramiques thermoélectriques de formulation In2-xGexO3
Combe, Emmanuel ULg

Doctoral thesis (2011)

Ce travail de thèse porte sur l’étude des relations procédé, micro/nanostructures et propriétés thermoélectriques de composés oxydes de formulation In2-xGexO3. Dans ce contexte, des techniques de synthèse ... [more ▼]

Ce travail de thèse porte sur l’étude des relations procédé, micro/nanostructures et propriétés thermoélectriques de composés oxydes de formulation In2-xGexO3. Dans ce contexte, des techniques de synthèse des poudres par chimie douce (procédé citrate), de mise en forme en milieu liquide (coulage en moule poreux) et de frittage non conventionnel des céramiques (frittage micro-ondes) ont été développées. Par comparaison à des procédés d’élaboration classiques, le développement du procédé citrate a permis la préparation de microstructures homogènes permettant d’optimiser les propriétés de transport. La figure de mérite ZT des composés In2-xGexO3 atteint ainsi des valeurs supérieures à 0,3 à 1000 K. Afin de mieux contrôler la densification pendant le frittage, l’utilisation d’une technique de mise en forme par coulage en moule poreux a été expérimentée et des densités après frittage proches de la densité théorique ont pu être obtenues grâce à une mise en ordre optimisée des particules dans les composés crus. Le développement du frittage micro-ondes à ce type de matériau a par ailleurs permis d’obtenir des microstructures très fines (taille de grains inferieure à 500 nm). Un dispositif thermoélectrique (surface de 35 × 40 mm², 56 jambes) de formulations Ca3Co4O9 et In1.994Sn0.006O3 a été également réalisé. Celui-ci délivre une puissance de 480 mW pour un gradient de température de 550 K. Ces différentes études ouvrent des perspectives intéressantes dans l’élaboration de composés et de dispositifs thermoélectriques à base d’éléments oxydes présentant des performances accrues. [less ▲]

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See detailEtude des propriétés physico-chimiques et technofonctionnelles des crèmes végétales en relation avec les conditions de reconstitution
Anihouvi, Prudent Placide ULg

Doctoral thesis (2011)

In this work, an integrated approach was adopted to study vegetal creams in order to have a global understanding of their properties. This approach included: (i) the influence of fat and other ingredients ... [more ▼]

In this work, an integrated approach was adopted to study vegetal creams in order to have a global understanding of their properties. This approach included: (i) the influence of fat and other ingredients of the formulation, particularly a low molecular weight surfactant, Tween 60 (ii) and the manufacturing process implemented for their preparation. The effect of fat was investigated by adopting an original approach that consisted in studying both the thermal and structural behavior of the non-emulsified fat (NEF) and the emulsified fat (EF). This clearly demonstrated the impact of the physicochemical characteristics of fat on the physicochemical and technofunctional properties of creams. It well established that small differences in the composition of fats may have great effects on the technofunctional behavior of creams. The influence of fat on the final properties of creams was mainly marked through the crystallization and melting behaviors of fat, and through the crystalline varieties formed during maturation. The effect of temperature on the stability of creams based on the physical evolution of the fat was also highlighted. The addition of tween 60 to the formulation significantly improved the properties of particle size, rheology, stability and whipping of creams. This improvement was the result of not only synergistic effect of surfactant molecules of buttermilk and tween 60 during emulsification but also desorption of proteins from the drop surfaces and modification of crystallization of the EF. The study of the influence of the process showed that the choice of the emulsification method and operating parameters are important considerations in the reconstitution of creams. It was shown that it was possible to modulate the properties of creams by only modifying the process. [less ▲]

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See detailAnalytical strategies for the detection of counterfeit erectile dysfunction drugs
Sacré, Pierre-Yves ULg

Doctoral thesis (2011)

Since the late eighties, when it was first mentioned, the worldwide phenomenon of pharmaceutical counterfeiting is growing. Belgian customs often encounter presumed counterfeited medical products in ... [more ▼]

Since the late eighties, when it was first mentioned, the worldwide phenomenon of pharmaceutical counterfeiting is growing. Belgian customs often encounter presumed counterfeited medical products in Belgian airports and ports because of their central position in Europe and their importance in the transit of goods. Further and deeper analyses are required to assess the counterfeit character of these goods and to provide a scientific basis for the eventual legal procedure. As reference laboratory for the federal agency for medicines and health products (FAMHP), the Scientific Institute of Public Health (IPH) frequently analyses illegal and counterfeit pharmaceutical preparations. The present research project was started with the objective of evaluating several existing methods and developing new analytical methods to detect counterfeit erectile dysfunction drugs. This thesis is focused on the analysis of illegal samples of phosphodiesterase type 5 inhibitors (PDE5-i) containing drugs because these are the most counterfeited pharmaceutical specialities in Belgium. The research was divided into a spectroscopic and a chromatographic part: Infrared based spectroscopies have already demonstrated their ability to detect counterfeit drugs. The first part of the study evaluates the capacity of each technique (mid-infrared (mid-IR), near-infrared (NIR) and Raman spectroscopy) separately and their combinations to discriminate genuine from illegal tablets. Then, the Classification And Regression Trees (CART) algorithm has been used to classify the different samples following the classification system of the Dutch National Institute for Public Health and the Environment (RIVM). The second spectroscopic approach used Raman microspectroscopy mapping to detect counterfeited Viagra®. This technique allows the detection of different compounds according to their Raman spectrum but also the study of the distribution of a selected ingredient among the core of a tablet. The chromatographic part consists of the development and validation of a new Ultra High Pressure Liquid Chromatography method coupled with a UV diode array detector (UHPLC-DAD) and compatible with mass spectrometry (MS) to detect and quantify the three authorised phosphodiesterase type 5 inhibitors (sildenafil, tadalafil and vardenafil) and five of their analogues in illegal pharmaceutical preparations. This method has been validated between +/- 5% acceptance limits using the total error approach and has been compared to the official Viagra® assay method. The ability of HPLC-UV impurity fingerprints to detect illegal samples and to predict whether a new unknown sample is genuine has also been evaluated. The developed analytical methods may be included in a general approach to detect counterfeit drugs containing PDE5-i. This generic approach may also be used to detect other types of counterfeited drugs but should therefore be adapted for each type of medicine. [less ▲]

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See detailIntroduction à la démarche spirituelle des moines errants de l'Egypte copte (250-451). Une étude fondée sur la "Mission de Paphnuce" et les principales sources littéraires du monachisme errant de l'époque concernée
Malevez, Marc ULg

Doctoral thesis (2011)

Having given the definition of the words "monks" and "wanderer", the thesis try to demonstrate that the spiritual step as it is presented by Evagrius Ponticus corresponding to the reality that was in the ... [more ▼]

Having given the definition of the words "monks" and "wanderer", the thesis try to demonstrate that the spiritual step as it is presented by Evagrius Ponticus corresponding to the reality that was in the spirit of the wanderer monks in Coptic Egypt and not a philosophical construction, based mainly on his experience outside Egypt. We will reconstitute and put in order the essential anachoristic monastic step, since the renouncement of marriage and fatherhood until the final getting of the Charism of the perfect and a saint on earth, as it appears from the main literary sources of that era. The thesis is also based on three Coptic manuscripts, three Arabic Manuscripts and five Ethiopian Manuscripts of the "Mission of Paphnutius", a travel story written in the fourth century. The thesis demonstrates also the characteristic idiorrhytmic and without doubt essentially reasonable of the step of the monks. [less ▲]

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See detailUtilisation des composts de biodéchets ménagers pour l'amélioration de la fertilité des sols acides de la province de Kinshasa (République Démocratique du Congo)
Mulaji Kyela, Crispin ULg

Doctoral thesis (2011)

This work is part of the research for appropriate methods for sustainable management of the sandy soils of the province of Kinshasa (Democratic Republic of Congo), in order to ensure and guarantee the ... [more ▼]

This work is part of the research for appropriate methods for sustainable management of the sandy soils of the province of Kinshasa (Democratic Republic of Congo), in order to ensure and guarantee the adequate food security. It consists of a scientic research of the use of composts produced from household organic waste in improving the quality of sandy soils to the province of Kinshasa. The general objective pursued in this work is to evaluate the impact of four repeated applications of organic matter from bio-waste compost on chemical and biochemical parameters dynamics in acid sandy soils and their productivity. A pilot composting on a small scale has been installed for the production of composts from municipal solid waste and characterization of composts obtained has revealed the agronomic potential that presents this material. The diagnosis of the condition agropedological soils revealed that soils of the three study sites are sandy classified as rubics arenoferrasols (dystrics), have excellent physical conditions for drainage, air circulation and root penetration possess variables charges colloids, show an acid reaction, low organic matter and low nutrient minerals contents. In addition, their water and nutrients retentions capacity are very limited, and are the main soil constraints to agricultural productivity of these soils. After four growing seasons in real environments, the study of the reaction with the soil organic amendments (20, 40, 60 t.ha-1 MB) gave satisfactory results. The provision of continuous additions of organic composts significantly increased the values of pH, TOC, CEC, SB eff and reduced the rate of exchangeable Al saturation in the three sites. With the highest dose T3 (60 t.ha-1 MB), the pH increased at least 0.8 units and the carbon content multiplied by 2.5 to 3 on the three sites. CEC values increased from 3.3 to 5.02 cmol(+)mg.kg-1 and the toxic aluminum saturation decreased more effective than 90%. Regarding biochemical parameters (microbial carbon & nitrogen, RB, RIS, APA, Unt, Ut), compost treatments induced a significant improvement in function and doses applied throughout the experiment. These contributions have induced microbial activity which contributed to the increase in soil nutrients (N, P, ...) by microbiological activities. The availability of nutrients and fourniture of carbon by the composts explain these increases. In addition, yields on different test plants (Glycine max L. Merr, Arachis hypogaea L. and Hibiscus sabbariffa L.) were positively influenced by the treatments of organic composts household wastes. Compared with mineral fertilizers, their fertilizing potential is not negligible. According to the results observed, doses ≥ 40 t.ha MB-1 should be to keep and maintain an acceptable level of fertility and yields potentiel of crops. But low doses were more efficient than high doses of agronomic point of view. Doses ≤ 20 t.ha-1 MB are recommended in annual crop and regular. Phosphorus was found to be the most limiting element to agricultural production of soil sites studied whatever of the types of amendments and cultures used. Finally, the study indicates that for reasons of efficiency, availability and funds increased production may be obtained through synergy between the composts used in small quantities and fertilizer mineral supplements. [less ▲]

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See detailContribution of cobalt-mediated radical polymerization to macromolecular engineering and photodynamic therapy
Hurtgen, Marie ULg

Doctoral thesis (2011)

Cobalt-mediated radical polymerization (CMRP) is an emerging class of controlled radical polymerization technique based on the reversible deactivation of the propagating radicals by a cobalt complex. This ... [more ▼]

Cobalt-mediated radical polymerization (CMRP) is an emerging class of controlled radical polymerization technique based on the reversible deactivation of the propagating radicals by a cobalt complex. This thesis aims at broadening the nature, the structure, the properties and the end-use of (co)polymers accessible by CMRP. The first part of this work is devoted to the synthesis of novel statistical, graft and block copolymers by CMRP. First, the statistical copolymerization of conjugated (n-butyl acrylate) with a non-conjugated one (vinyl acetate) has been successfully controlled by bis(acetylacetonato)cobalt(II). The optimal experimental conditions were then implemented to the copolymerization of vinyl acetate with poly(ethylene glycol) acrylate, which yielded (quasi-)diblock amphiphilic graft copolymers for potential biomedical applications in one step. CMRP also revealed successful for the synthesis of well-defined thermo-responsive copolymers based on poly(N-vinylcaprolactam), either amphiphilic or double-hydrophilic at room temperature. In the second part of this thesis, we investigated the potential of CMRP for the synthesis of new agents for cancer photodynamic therapy. The synthesis of such photosensitizers relied on the chain-end functionalization by [60]fullerene of water-soluble (co)polymers (or precursors) prepared by CMRP. The photodynamic activity of poly(vinyl alcohol)/C60, poly(N-vinylpyrrolidone-co-vinyl acetate)/C60 and poly(PEG acrylate-co-vinyl acetate)/C60 nanohybrids were assessed through photophysical and in vitro experiments. Also, the ability of the nanohybrids to avoid recognition by the immune system was evaluated by a protein adsorption test. Finally, some hints on how to improve the synthesis of the nanohybrids - and therefore, their photodynamic activity - were provided by a mechanistic study of the grafting onto C60 of macroradicals released by cobalt end-capped polymers [less ▲]

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See detailUne expérience critique de la pensée. Essai sur les kantismes de Foucault (1961-1969/1978-1984)
Bolmain, Thomas ULg

Doctoral thesis (2011)

Ma thèse se propose de démontrer les points suivants : 1. La pensée de Foucault doit être rapportée comme à sa condition de possibilité philosophique à l’émergence historique de la pensée critique telle ... [more ▼]

Ma thèse se propose de démontrer les points suivants : 1. La pensée de Foucault doit être rapportée comme à sa condition de possibilité philosophique à l’émergence historique de la pensée critique telle qu’elle est associée au nom de Kant : j'ai étudié, dans leurs modalités diverses, « les kantismes de Foucault » ; 2. Pour le comprendre, il est de première importance de se concentrer sur les deux extrêmes de son parcours philosophique (1961-1969 et 1978-1984) ; 3. Ce postulat en implique un autre, de nature méthodologique : le choix de privilégier une reconstruction conceptuelle plutôt que chronologique de l’œuvre de Foucault ; ainsi peut-on mettre en évidence la cohérence très forte qui anime son parcours, sous les discontinuités évidentes qui l’affectent ; 4. La cohérence philosophique de la pensée de Foucault est liée à trois éléments : - l’unité d’une méthode, d’une certaine attitude de la pensée (nominalisme matérialiste réalisé dans la forme d’une archéo-généalogie) ; - l’insistance d’une question toujours posée dans le cadre de l’interrogation critique et d’une reprise partielle des motifs du transcendantal et surtout de la finitude ; cette question se résume du passage de la critique de la question anthropologique classique (Qu’est-ce que l’homme ?) à une enquête portant sur les modes d’être historiques du sujet (Que sommes-nous aujourd’hui ?) ; - la reprise constante de trois concepts qui font le cœur de la conceptualité philosophique moderne et qui forment chez Foucault un réseau à la relative systématicité : ceux d’expérience, de pensée et de critique ; 5. Le concept d’expérience est la pierre de touche de toute l’œuvre de Foucault : seule sa reconstruction patiente permet de saisir, de décrire et d’élaborer de manière satisfaisante la manière de penser qui est la sienne, dans son rapport critique à la pensée de Kant. Une fois rapportée à sa condition historique de possibilité, l'oeuvre de Kant, on comprend à la fois la nécessité conceptuelle de la proposition philosophique de Foucault mais aussi, par suite, les limites de sa proposition éthico-politique. C'est ce que j'ai nommé le nihilisme achevé ou positif de Foucault, la pure exigence d'une transformation micro-politique indéterminée et non-fondée de l'état de choses donné. Aller plus loin que celle-ci supposerait de reprendre la question philosophique directrice de Foucault - comment la transformation du sujet dans l’histoire vers un surcroît d’autonomie s’articule-t-elle à sa finitude radicale ? - aux abords de la dialectique, et en particulier en fonction de concepts critiqués par l'auteur, ceux de négativité et de totalité. [less ▲]

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See detailNanostructuration induced by self-organization of polystyrene nanospheres as a template for the controlled growth of functional materials
Colson, Pierre ULg

Doctoral thesis (2011)

In the last few years, nanosphere lithography emerged as an inexpensive, material specific and high-output nanostructure fabrication process to manufacture arrays of periodic structures. The goal of this ... [more ▼]

In the last few years, nanosphere lithography emerged as an inexpensive, material specific and high-output nanostructure fabrication process to manufacture arrays of periodic structures. The goal of this thesis was centered on both parts of the nanosphere lithography process, namely first the optimization of monolayer colloidal masks prepared by spin coating of monodisperse polystyrene (PS) nanospheres and secondly the use of these masks to develop new attractive applications in various fields. In order to assess the quality of the manufactured colloidal crystal masks, we developed a computerized image analysis procedure (Matlab) based on SEM micrographs. We successfully performed the different stages of the image analysis in such a way to discriminate and identify each nanosphere. As a quantification of order in the self-organized nanospheres, we chose to determine the percentage of hexacoordinated nanospheres by computing the distances between each of them. We applied experimental design to spin coating to evaluate the efficiency of this method to extract and model the relationships between the experimental parameters and the degree of ordering in the particles monolayers. We identified adequate spin coating parameters to synthesize large defect-free domains, reaching up to 200 μm2, which is the highest value ever reported for samples prepared by spin coating. Statistical analysis highlighted that rapid substrate acceleration and high rotation rates are necessary to get large, well-ordered areas. We also studied the surfactant concentration usually added to the beads suspension or the use of reactive ion etching (RIE) process to modify the masks. By using PS nanosphere templates (490 nm or 250 nm diameter), we successfully manufactured large arrays of L10-Fe50Pt50 and Co nanotriangles with uniform sizes. In addition to crystallographic and microstructural characterizations, we evaluated the magnetic properties of the nanostructures both from a qualitative (MFM) and quantitative (SQUID) point of view. The magnetic stability of the single-domain FePt nanodots was evidenced by focused MOKE analysis. This is of major importance for further use in magnetic storage applications and has never been reported yet. The soft magnetic Co nanodots displayed either single domain or vortex domains states, depending on the magnetization direction. The MOKE hysteresis loops revealed an increased coercive field compared with thin films. This is probably due to a specific magnetization reversal process caused by the shape of the nanodots. Oxide nanostructures were then manufactured. The polystyrene templates (490 nm diameter) were used for the guided hydrothermal growth of well-aligned ZnO nanowires. The control of the spacing between the nanowires combined with high c-axis preferred orientation led to higher dye loading values compared with continuous unpatterned films. This was undoubtedly attributed to an increased accessible surface area due to the patterning. Moreover, the increased roughness due to the patterning induced a higher water contact angle compared with an unpatterned ZnO nanowire array. Reversible superhydrophylicity to hydrophobicity was observed and controlled by successive UV illumination and O2 annealing. The achievements attained in this work have brought a significant contribution to the field of nano- and microfabrication. New pathways were opened for interesting future work with respect to continued fundamental and applied research. [less ▲]

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See detailExperimental and numerical study of the factors influencing the performances of magnetic screens made of high temperature superconductors
Fagnard, Jean-François ULg

Doctoral thesis (2011)

In this thesis, we investigate in details the magnetic shielding processes in high temperature superconductors. We aim at predicting and measuring the influence of the parameters governing the ... [more ▼]

In this thesis, we investigate in details the magnetic shielding processes in high temperature superconductors. We aim at predicting and measuring the influence of the parameters governing the superconducting behaviour (e.g., the critical current density Jc and its field dependence) on the magnetic flux penetration inside hollow cylinders. Three objectives are pursued. The first objective is to characterize the performances of cylindrical magnetic shields made of various high temperature superconductors (Bi-2223, Bi-2212, Y-123) for several external parameters that can be directly controlled in the experiments. These include the temperature, the geometry of the magnetic screen, the amplitude of the applied magnetic field, its orientation (H // or ⊥ cylinder axis) and its frequency (in the case of an AC excitation). The focus has been put on the effect of the sweep rate of the applied magnetic field, dBapp/dt, on the threshold magnetic flux density, Blim, above which the magnetic shielding is no longer efficient. We show that the curve of dBapp/dt vs. Blim can be directly related to the E(J) constitutive law and we explain how the field dependence of the critical current density affects the relationship between both curves. A wide range of electric field levels is investigated in this thesis thanks to the use of a number of experimental techniques. The experimental set-ups required for these investigations are described in a separate chapter where the performances and limitations of each set-up is put forward. The second objective of the thesis is to confront experimental data and numerical simulations using models of increasing complexity. We present two numerical models that take into account the strongly non-linear E(J) relationship characterizing the superconducting behaviour. The first numerical model is based on the Brandt algorithm. This model is able to describe magnetic shielding experiments which involve time-varying magnetic fields on (i) infinite samples subjected to transverse magnetic fields or on (ii) samples of finite size in axisymmetric geometries subjected to axial magnetic fields. The second model is based on a finite element method (using the GetDP software). This model can be used for both axisymmetric 2D modelling and full 3D modelling. In the latter case, it provides extremely useful information for understanding configurations where the applied magnetic field and the hollow cylinder do not present a particular symmetry. Both 2D and 3D models are able to provide current and field distributions in the superconductor. The confrontation between experimental and modelling results allows us to better understand how physical properties (critical temperature Tc, critical current density Jc, ...) and geometry affect the magnetic shielding performances (shielding factor SF, threshold induction Blim). Conversely, we present three different practical procedures using either the analytical Bean model or a 2D numerical model in order to determine the constitutive law parameters of the superconducting materials from data measured on hollow cylinders. As a third objective, we aim at investigating how the different types of HTS magnetic screens of moderate dimensions (a few cubic centimetres) could be scaled up in order to provide larger shielded volumes. Three methods are explored. The first method to build larger magnetic screens (typically ten(s) of centimetres) is to find means to assemble several (pieces of) superconducting hollow cylinders to obtain a large shielding enclosure. Experiments are carried out on superconducting cylinders cut either along or perpendicular to their axis. The influence of the cut width and the angle of the applied magnetic field with respect to the cut plane are studied. Modellings are carried out on shorter cylinders in order to understand how the presence of the cut modifies the current distribution and thus the magnetic shielding properties. The second method consist in characterizing the magnetic shielding of several hollow cylinders made with the same superconducting material but having different sizes. This helps us in determining whether the manufacturing process is able to provide large cylinders with good magnetic shielding performances. In a last method, we investigate an architecture of superconducting magnetic screens that differs from those based on bulk hollow cylinders. The idea is to exploit the high Jc-performances of superconducting tapes (based on thin film technology) to build magnetic shielding structures which can be easily scalable. The measurement results obtained on such structures are promising as the actual limitation seems to be geometrical. Using more superconducting tapes in order to achieve a higher aspect ratio should give magnetic shields which are as efficient as bulk cylinders. [less ▲]

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See detailLe contexte urbain et climatique des risques hydrologiques de la ville de Butembo (Nord Kivu/RDC)
Muhindo, Sahani ULg

Doctoral thesis (2011)

Butembo, a small town in the humid tropical region, is a typical case of, a city with an exceptionally rapid population growth. The spontaneous concentration of populations due to uncontrolled migration ... [more ▼]

Butembo, a small town in the humid tropical region, is a typical case of, a city with an exceptionally rapid population growth. The spontaneous concentration of populations due to uncontrolled migration on a relatively small territory has led to urban sprawl. Soil sealing of large areas caused by a rapid spatial expansion of the town has generated environmental problems that affect the urban structure. The city is facing diverse hydrological risks. Progressive and regressive gully development accelerates and increasingly affects water availability. In recent years, the urban area faces floods, perceived locally as exceptional. The remobilization of old landslides locally causes damage. Since its inception, Butembo has never had an objective reference map. The only ones which are available are manually drawn. It is known that land use planning can fight effectively against most major risks in so far as the elements that govern their occurrence are known and that the areas at risk can be located and defined on the basis of objective and scientific criteria. The main goal of this thesis is to produce a map of and for the city of Butembo which can help to support decision making or at least to understand the reasons of the environmental degradation in the urban area. In that direction, this thesis leads to editing a map of hydrological risks. It is based on approaches combining remote sensing and terrain activities. A detailed analysis of rainfall events is made to see if the rains did influence the environmental problems in the town of Butembo. The results reveal an exceptional urban expansion. The urban sprawl of Butembo increased from 2,39 km² in 1957 to 85,83 km² in 2008, approximately 54 % of 158,95 km². This increase in urban area is the result of exceptional population growth in the town. Indeed, the population rose from 9 653 in 1957 to 581 449 inhabitants in 2008. This urbanization has resulted in a new land use with all the consequences on the urban landscape. Since 1957 valley and hillslope gullying remained all the time confined spatially within the diachronic urbanized expansions. Urbanization precedes the development of gullies and these are confined to areas where the runoff coefficient increased by urbanization. For the time being, there is not yet fusion between progressive and regressive gullies. In the future, flooding threats all the flat valley bottoms in the case nothing is done. Landslides are active and are in the creep phase. 11 of the 16 landslides inventoried are partially co-triggered by seismic. Finally, the damage to the urban structure cannot be ascribed to changes in the rainfall pattern over the 30 last years. All the rains of recent years are normal for the city as their recurrence time is under 6 years. The main cause of environmental problems within the city is urbanization. Remediation methods require intervention not only in the field of runoff evacuation. The problems must also be tackled upstream, on the slopes, using all the techniques that can prevent or reduce the generation of runoff. [less ▲]

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See detailIdentification et caractérisation de bactériocines produites par deux bactéries lactiques (Enterococcus faecium CWBI-B1430 et Enterococcus mundtii CWBI-B1431) isolées à partir de fromages frais artisanaux péruviens
Aguilar Galvez, Ana Consuelo ULg

Doctoral thesis (2011)

A screening of lactic acid bacteria (LAB) with bacteriocin-like inhibitory activity against Listeria monocytogenes was performed. The screening was conducted in 27 traditional artisanal-produced cheeses ... [more ▼]

A screening of lactic acid bacteria (LAB) with bacteriocin-like inhibitory activity against Listeria monocytogenes was performed. The screening was conducted in 27 traditional artisanal-produced cheeses obtained from different Peruvian regions. Two thousand two hundred and seventy seven strains (2277) were isolated, of which 20 exhibited bacteriocin-like inhibitory activity, two strains stand out for having higher activity against listeria, as well as stability at pH value of 2-11 and a thermal stability. The two strains were identified using 16 S ribosomal DNA method, and were registered in the GenBank database of NCBI (National Center for Biotechnology Information). These were Enterococcus faecium CWBI-B1430 (accession number EF591817) and Enterococcus mundtii CWBI-B1431 (accession number EF591816). Two of the major factors concerned in a potential health risk associated with the genus Enterococcus were evaluated, and it was demonstrated that they were sensitive to vancomycin and showed no hemolytic activity. Genetic studies showed the presence of four putative bacteriocin genes in both strains, these were enterocin A, enterocin B, enterocin P, and mundticin KS. The reverse transcription-PCR analysis was realized, the expression of the bacteriocin genes enterocin A, enterocin B, and mundticin KS in CWBI-B1430 was showed, while bacteriocin genes enterocin P and mundticin KS was demonstrated in CWBI-B1431. These results are the first report of the expression of mundticin KS in E. faecium and enterocin P in E. mundtii. Also, the expression was studied at different temperatures, unlike the enterocin P, where only a positive signal was obtained at 12 and 37°C. All other enterocin showed positive signal at 12, 30, 37 and 42°C. The production of bacteriocins on a small scale, in both strains was studied. It was investigate the influence of initial pH (4.5, 5.0, 5.5, 6.0, 6.5 and 7.0), temperature (25, 30 and 37°C) and oxygen level (anaerobic, microaerobic and aerobic). The conditions for maximizing the production of bacteriocins are : initial pH of 7.0, at 37 °C, and microaerobic conditions for CWBI-B1430 strain; initial pH of 6.5, at 37 °C, and an aerobic condition for CWBI-B1431. The influence of the source of carbon and nitrogen, as well as their concentration in the bacteriocin production, was studied. The study of the production of short-chain fatty acids by these strains of multiproducing bacteriocins, showed the propionic acid as the most important. The purification study confirmed that the two bacteria in question are multi-producing of bacteriocins, as shown by the obtained chromatograms, showing different molecular weights, different charge and hydrophobicity level. The results of in situ application of the two selected strains or their supernatant does not show the same efficiency as those obtained in vitro. Factors such as temperature and food composition may be the origin of these results. Therefore, we propose the use of both strains in the food industry, for being multi-producing bacteriocins, have broad spectrum of inhibition and because the substances that produce have functional properties that are useful in the food industry. [less ▲]

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See detailTHE ROLE OF CUSTOMER PERCEIVED EMPLOYEE EMOTIONAL COMPETENCE IN SERVICE ENCOUNTERS
Delcourt, Cécile ULg

Doctoral thesis (2011)

The present dissertation is based on three studies, sharing one common theme: employee emotional competence (EEC). The overall aim of this dissertation is to examine the effect of customer perceptions of ... [more ▼]

The present dissertation is based on three studies, sharing one common theme: employee emotional competence (EEC). The overall aim of this dissertation is to examine the effect of customer perceptions of employee emotional competence on their evaluations of critical service encounters. To achieve this goal, each study builds a theoretical framework and presents empirical assessments of aspects of the issue under consideration. While psychology scholars have conceptualized, measured, and evaluated the impact of EEC in work-related relationships (i.e., internal perspective of EEC), the role of EEC in customer-related relationships (i.e., service encounters) has received little attention by marketing scholars. We argue in this dissertation that a customer perspective of EEC is necessary to examine EEC in such context. Recent studies in the service literature have suggested that EEC could be valuable in service encounters–especially in critical service encounters since customers want employees to recognize the uniqueness of their personal experience (Price et al., 1995b). Given the potential influential role of EEC in a marketing context, researchers have called for further investigation (Kidwell et al., 2011; Verbeke et al., 2008). Therefore, this dissertation approaches the concept of EEC by first focusing on emotional competence (i.e., the actual demonstration of emotionally competent behaviors by the employee) instead of emotional intelligence (i.e., the potential one employee has to demonstrate emotionally competent behaviors). In this respect, we examine customer perceptions–rather than employee perceptions or supervisor perceptions of EEC–since these last measures are subject to important biases and since only customers can evaluate if the employee has actually displayed emotionally competent behaviors during the service encounter. More specifically, the focus is on the exploration of EEC and its effects on customer outcomes. Based on a review of the literature from various disciplines and research streams, comprehensive models are constructed, summarizing theoretical propositions and hypotheses. The first study examines in a field study the impact of customer perceptions of EEC on customer satisfaction and loyalty in high-contact services. The mediating role of rapport is examined. We found that EEC influence both customer satisfaction and loyalty. Rapport mediates both relationships. The second study aims to conceptualize EEC in service encounters and to develop a short, valid, and reliable measure based on that conceptualization. By using a rigorous scale development procedure, we define EEC as customer perceptions of employees’ abilities to perceive, understand, and regulate customer emotions in a service encounter to ensure harmonious encounters. This measure of EEC is strongly related to key customer outcomes such as customer satisfaction. The third study aims to understand in an experimental design the role of EEC compared to employee technical competence (ETC) in emotionally charged service encounters. We found that EEC moderates the relationship between ETC and customer outcomes such as negative customer emotions, rapport, and service encounter satisfaction. When EEC is low, the impact of ETC on those variables is low or even non significant. When EEC is high, ETC strongly influences those customer outcomes. Together, the three studies provide rich insights on the impact of EEC on customer outcomes in a service encounter context. To improve the customer’s experience in service encounters, managers should encourage their contact employees to display emotionally competent behaviors by perceiving, understanding, and regulating customer emotions. When employees have high EEC, the impact of ETC on customers is the highest. Rapport mediates the relationship between EEC and key customer outcomes such as customer satisfaction and loyalty. [less ▲]

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See detailEntre Union européenne et Région wallonne : multiplicité des échelons de pouvoir et subsidiarité territoriale Analyse de la subsidiarité territoriale au travers des directives Seveso, IPPC, responsabilité environnementale et de leurs mesures de transposition en Région wallonne.
Hanson, Sophie ULg

Doctoral thesis (2011)

La Région wallonne s’inscrit dans un contexte organisationnel particulier. D’une part, elle constitue une composante d’un État membre de l’Union européenne. D’autre part, elle fait partie d’un État à ... [more ▼]

La Région wallonne s’inscrit dans un contexte organisationnel particulier. D’une part, elle constitue une composante d’un État membre de l’Union européenne. D’autre part, elle fait partie d’un État à structure fédérale comportant une entité fédérale, des entités fédérées et des collectivités locales (provinces, communes). Il est permis de s'interroger, dans ce contexte, sur la nature des relations que peut entretenir la Région wallonne avec les entités gravitant autour d’elle. Le principe de subsidiarité, dans sa fonction territoriale, peut constituer une clé de lecture dans la mesure où il est indissociable des systèmes institutionnels multi-niveaux. Il implique que ce soit l’échelon qui est le plus proche des citoyens qui soit privilégié afin de remplir une tâche. Si toutefois, il ne parvient pas à rencontrer un objectif déterminé, l’échelon supérieur peut intervenir s’il peut satisfaire ce dernier de manière plus efficace. La question centrale qui a guidé la recherche a donc été de savoir, au travers de l’exemple de la Région wallonne, si les rapports entre les échelons de pouvoir, de la commune à l’Union européenne s’effectuent en application du principe de subsidiarité, dans sa fonction territoriale. Trois directives européennes importantes ressortissant au domaine de l'environnement (Seveso, IPPC et responsabilité environnementale) ainsi que leurs mesures de transposition en Région wallonne ont été examinées à l'aune de ce principe. [less ▲]

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See detailDes projets aux réseaux: la construction d'un compromis
Vandenborne, Emilie ULg

Doctoral thesis (2011)

Cette thèse étudie la construction en réseaux des projets. Elle a pour objet une sociologie de l’action en réseaux appuyée d’une sociologie des normes et d’une sociologie de l’acteur-réseau. Elle ... [more ▼]

Cette thèse étudie la construction en réseaux des projets. Elle a pour objet une sociologie de l’action en réseaux appuyée d’une sociologie des normes et d’une sociologie de l’acteur-réseau. Elle interroge les comportements collectifs autour de projets au sein du secteur biotechnologique. La question centrale qui se pose est celle de l’apparition de nouvelles formes de gouvernance réticulaire à partir d’une configuration par projets. [less ▲]

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See detailConception et synthèse de nouveaux complexes de ruthénium pour la formation catalytique de liaisons C–C
Borguet, Yannick ULg

Doctoral thesis (2011)

During the last decade, catalytic methods enabling the formation of single and multiple C–C bonds have sparked a major interest from the Chemists community. Among them, olefin metathesis has emerged as a ... [more ▼]

During the last decade, catalytic methods enabling the formation of single and multiple C–C bonds have sparked a major interest from the Chemists community. Among them, olefin metathesis has emerged as a powerful tool, opening unique routes to synthesize organic compounds and polymers. This is mainly due to the advent of well-defined ruthenium–benzylidene complexes first developed by Grubbs and co-workers in the early 1990’s. Since then, countless structural alterations have been made to these archetypal compounds in order to tailor their activity, stability, solubility, . . . However, the synthesis of these derivatives may be tedious and costly since it almost systematically requires the use of the Grubbs 1st generation catalyst as a starting material. Therefore, non-proprietary catalysts with high activity are still eagerly sought. This thesis is mainly focused on the design of straightforward and reliable syntheses of new complexes derived from the homobimetallic molecular scaffold (I) first reported by Severin in 2005. Our first aim was to enhance the catalytic activity of such compounds in olefin metathesis and in controlled radical reactions. [less ▲]

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See detailRôle des moustiques Culicidae, de leurs communautés microbiennes et des réservoirs vertébrés, dans la transmission des arbovirus à Madagascar
Raharimalala, Fara Nantenaina ULg

Doctoral thesis (2011)

These last ten years, Indian Ocean islands have been the theatre of severe epidemics of arboviroses. However, little information was available about the local dynamics of the virus transmission and ... [more ▼]

These last ten years, Indian Ocean islands have been the theatre of severe epidemics of arboviroses. However, little information was available about the local dynamics of the virus transmission and identity of the vector species and vertebrates réservoirs involved. Madagascar island was chosen for its high endemic biodiversity, contrasting climatic conditions and drastic changes in habitats due to an increase anthropic pressure. These factors increase the epidemiological risks of infectious diseases. In this context, our objective was to characterize the role of Culicidae as major vectors, the associated microbial communities, and wild vertebrates (lémurs) as potential réservoirs in the transmission arboviroses. Molecular techniques allowed udpdating the biogeography of Aedes and showed the dominance of Aedes albopictus competent to chikungunya virus. Other mosquitoes captured belonged to Culex antennatus, Culex decens, Culex quinquefasciatus et Mansonia uniformis. The bacterium Wolbachia was detected in most mosquito especies,but Culex antennatus. Searching of arboviruses by qRT‐PCR revealed infection of Culex antennatus and lemurs (Lepilemur edwardsi et Eulemur rufus) by the rift valley fever virus. [less ▲]

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See detailContribution to the epidemiology of bovine tuberculosis in northern Ecuador
Proaño Perez, Freddy ULg

Doctoral thesis (2011)

See attached document, page vii

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See detailImpact des facteurs de contexte sur le design des systèmes de contrôle de gestion dans les collectivités locales béninoises: Une approche contingente
Togodo Azon, Degodo Aimé ULg

Doctoral thesis (2011)

Très peu d’études empiriques ont analysé les facteurs qui influencent le design des systèmes de contrôle de gestion dans les collectivités locales de l’Afrique au Sud du Sahara. La présente recherche, qui ... [more ▼]

Très peu d’études empiriques ont analysé les facteurs qui influencent le design des systèmes de contrôle de gestion dans les collectivités locales de l’Afrique au Sud du Sahara. La présente recherche, qui prend pour cadre le Bénin, explore les facteurs qui influencent le design des systèmes de contrôle de gestion dans les communes béninoises. Pour ce faire, nous avons développé six chapitres complémentaires articulés en trois parties. Dans une première partie, nous avons fait un état de la littérature qui aboutit à un modèle conceptuel. Ce modèle présente les différents outils de contrôle de gestion et les facteurs organisationnels et extra-organisationnels susceptibles d’influencer le choix des outils. La deuxième partie est une étude empirique hypothético-déductive à base de questionnaires sur soixante-dix communes béninoises. Dans cette partie, nous avons présenté les caractéristiques des systèmes de contrôle de gestion utilisés dans les communes béninoises et identifié les facteurs institutionnels et socioculturels qui influencent la configuration organisationnelle et le design des systèmes de contrôle de gestion dans les collectivités locales béninoises. La troisième partie est une étude empirique inductive qui présente trois études de cas. Ces études de cas, utilisées en complément et en approfondissement de l’analyse quantitative, ont révélé le rôle capital que joue le style de management adopté par les autorités locales dans la gestion du changement organisationnel et dans la maitrise des pressions politiques locales. Enfin, la recherche s’achève en dégageant les principales implications de notre modélisation sur l’introduction de la Nouvelle Gestion Publique en Afrique sub-saharienne et sur le type de décentralisation choisi par le Bénin. [less ▲]

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