References of "Doctoral thesis"
     in
Bookmark and Share    
See detailXérogels de carbone comme matériaux modèles pour l'étude du comportement électrochimique en tant qu'anodes de batteries Li-ion
Piedboeuf, Marie-Laure ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 19 (3 ULg)
Full Text
See detailIsolement et caractérisation de mutants affectés dans le transport d'électrons photosynthétique en anoxie chez la microalgue verte Chlamydomonas reinhardtii. Photoproduction d'hydrogène et Voie de biosynthèse de la phylloquinone.
Emonds-Alt, Barbara ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 15 (2 ULg)
Full Text
See detailIdentification de mécanismes moléculaires d’induction de la réponse immunitaire de type Th2 par les cellules dendritiques conventionnelles CD11b+ du poumon
Janss, Thibaut ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 93 (0 ULg)
Full Text
See detailLa viande des uns, la faune des autres. Analyse anthropologique de la conservation de la faune dans trois villages Badjoué de la zone forestière de l'Est-Cameroun
Dieudonné, Mélodie ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 25 (2 ULg)
Full Text
See detailL'apprentissage des conversations de conception. Analyse exploratoire des pratiques discursives et graphiques médiées par ordinateur.
Joachim, Guillaume ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 12 (1 ULg)
See detailDetection and characterization of transiting hot Jupiters
Delrez, Laetitia ULg

Doctoral thesis (2016)

Detailed reference viewed: 25 (3 ULg)
Full Text
See detail"Favorites of the Gods". The Seleucid Kings coping with the divine. A qualitative and quantitative approach of the numismatic evidence attesting the "discreet" divinization of the Seleucids"
Iossif, Panagiotis ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 17 (3 ULg)
Full Text
See detailOn the GMP production of [18]FUCB-H : Imaging neurotransmission
Warnier, Corentin ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 13 (1 ULg)
Full Text
See detailMécanismes moléculaires associés à l’induction de la pathogénicité chez Streptomyces scabies
Jourdan, Samuel ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 20 (1 ULg)
See detailHydrodynamics and bed stability at smooth-to-rough transitions. Experiments based on acoustic flow measurements
Duma, Diana ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 8 (3 ULg)
Full Text
See detailDevelopment of alternative methods to control aphids (Hemiptera: Aphididae): from wheat-pea intercropping to the use of semiochemical dispensers
Chevalier Mendes Lopes, Thomas ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 20 (7 ULg)
Full Text
See detailStructure and Dynamics of Ge-Se Liquids and Glasses under Pressure
Yildirim, Can ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 32 (3 ULg)
Full Text
See detailREFINEMENT OF PERI-ANAESTHESIA PRACTICES FOR LABORATORY ANIMAL CARE
Thomas, Aurélie ULg

Doctoral thesis (2016)

Detailed reference viewed: 4 (2 ULg)
Full Text
See detailDealing with storm impacts on the forest sector through integrated and systemic approaches at the regional level
Riguelle, Simon ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 25 (4 ULg)
See detailSynthesis of poly(ionic liquid)-type nanogels, by cobalt-mediated radical cross-linking copolymerization for coating applications
Weiss-Maurin, Mathilde ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 12 (2 ULg)
Full Text
See detailDevelopment and validation of analytical methods for quantifying isoflavones and equol in biological matrices
Daems, Frédéric ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 22 (2 ULg)
Full Text
See detailPerformance de l'indicateur Azote Potentiellement Lessivable pour l'évaluation de la gestion du nitrate en agriculture et du risque pour la qualité de l’eau
Vandenberghe, Christophe ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 40 (8 ULg)
Full Text
See detailRadiosynthesis and preclinical development of [18F]labeled tryptophan for human indoleamine 2,3-dioxygenase PET imaging
Henrottin, Jean ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 10 (3 ULg)
Full Text
See detailMethods and models for brain connectivity assessment across levels of consciousness
Amico, Enrico ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 22 (1 ULg)
Full Text
See detailMix and match: Essays on collective dynamics in nascent social entrepreneurship
Dufays, Frédéric ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 31 (8 ULg)
Full Text
See detailDynamics of ligands on gold surface to obtain Janus nanoclusters: A theoretical and experimental investigation
Lugo Preciado, Jesús Gustavo ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 14 (2 ULg)
Full Text
See detailCaractérisation multiscalaire de contaminations en éléments traces dans les sols : distribution spatiale et verticale, évaluation du transfert sol-plante-vers de terre et gestion potentielle par amendements organiques
Liénard, Amandine ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 31 (7 ULg)
Full Text
See detailLes conséquences civiles des polices administratives sur la vente immobilière. Etude comparée des droits wallon, flamand et bruxellois
Onclin, François ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 26 (11 ULg)
Full Text
See detailCaractérisation biochimique et structurale des tagatose-1,6-bisphosphate aldolases de classe I d’origine procaryotique
Freichels, Régine ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 17 (4 ULg)
Full Text
See detailBrain connectivity and sensory stimulation in disorders of consciousness
Heine, Lizette ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 17 (0 ULg)
Full Text
See detailL'ENSEIGNEMENT DU FRANÇAIS AUX ANGLOPHONES AU CAMEROUN : ANALYSE ET PROPOSITIONS DIDACTIQUES
Mouto Betoko, Christiane ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 38 (3 ULg)
Full Text
See detail« Le courtage associatif en développement et l’émergence de nouvelles élites rurales dans le Sud-Est marocain. Le cas de la région Drâa-Tafilalet »
Benidir, Mohammed ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 28 (4 ULg)
Full Text
See detailRôle du climat et de la compétition interspécifique dans la limitation de l'aire d'invasion d'Ambrosia artemisiifolia L. en Europe de l'Ouest
Ortmans, William ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 52 (14 ULg)
Full Text
See detailContribution to the study of the mineral hypothesis in relation to the Kashin-Beck disease in Tibet Autonomous Region
DERMIENCE, Michael ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 22 (2 ULg)
Full Text
See detailLe droit coutumier dans les ordres juridiques contemporains (19e-21e siècles). Étude comparative des pratiques judiciaires et de la doctrine
Braillon, Charlotte ULg

Doctoral thesis (2016)

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

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

Detailed reference viewed: 23 (5 ULg)
Full Text
See detailEntre traditions et innovations. La tête végétalisée dans les décors romains: origine, diffusion et signification d'un thème ornemental
Derwael, Stéphanie ULg

Doctoral thesis (2016)

La tête végétalisée est un témoin privilégié de la culture visuelle des Romains. Innovation de l’époque tardo-républicaine et proto-impériale, elle n’en demeure pas moins l’héritière du traitement formel ... [more ▼]

La tête végétalisée est un témoin privilégié de la culture visuelle des Romains. Innovation de l’époque tardo-républicaine et proto-impériale, elle n’en demeure pas moins l’héritière du traitement formel de figures telles que la Rankenfrau et le Rankengott et d’un symbolisme végétal séculaire. Elle évoque une nature naissante ou renaissante qui ne possède pas encore les frontières du cosmos ordonné, et fonctionne comme une épithète iconographique permettant de mettre en évidence un aspect particulier d’un personnage, tel le dieu Oceanus. L’étude des spécificités culturelles et des traditions iconographiques des différentes régions de l’Empire romain, couplée à la mise en série et à l’analyse contextualisée des documents, permet de mettre en évidence les formes de diffusion, de réception et d’appropriation de ce thème ornemental, de sa naissance à son assimilation par le monde chrétien. A côté de tendances relativement homogènes communes à l’Empire, se dessinent quelques courants particuliers, comme l’enrichissement nord-africain de la forme océanique, le renouveau oriental de la bordure à rinceau peuplé héritée de la tradition picturalisante hellénistique, ou « l’humanisation du végétal » gallo-germanique. Entre traditions et innovations, la tête végétalisée du monde romain développe des spécificités iconographiques pérennes qui lui confèrent une signification inhérente à toute forme d’hybridité végétale, tout en permettant à différentes visions du monde de s’exprimer en elle sans se dissoudre. [less ▲]

Detailed reference viewed: 25 (4 ULg)
See detailPrecision synthesis of poly(ionic liqui)s in aqueous media by cobalt-mediated radical polymerization
Cordella, Daniela ULg

Doctoral thesis (2016)

Poly(ionic liquid)s (PILs) are a subclass of polyelectrolytes that gained an enabling role in many fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids ... [more ▼]

Poly(ionic liquid)s (PILs) are a subclass of polyelectrolytes that gained an enabling role in many fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the flexibility and properties of macromolecules, and provide novel attractive functions. Recently, the precision design of novel PILs by controlled/living polymerization (CLP) techniques was intensively searched for developing emerging applications, such as those based on the self-assembly of block copolymers (BCPs). Indeed, combining the physicochemical properties of PILs with the self-assembly of BCPs is a route to easily produce innovative functional nanostructures that have a huge potential for many applications, e.g. for electrochemical devices, gas membranes, nanostructures materials, etc. Among the panel of poly(ionic liquid)-based block copolymers (PIL BCPs) that is available, vinyl imidazolium-based derivatives are highly attractive due their high charge density, the possibility to easily tune their properties by the nature of the alkyl chain, etc. However, when this PhD thesis started, their synthesis by direct polymerization of N-vinyl imidazolium-type monomers was challenging for most of the CLP techniques. Only few examples of vinyl imidazolium-based PIL BCPs were accessible by Reversible Addition Fragmentation Transfer (RAFT) polymerization or Cobalt-Mediated Radical Polymerization (CMRP), and in organic media exclusively. The aim of this PhD thesis was to develop a controlled radical polymerization technique for N-vinyl imidazolium-type monomers in water that would facilitate the precision synthesis of PIL BCPs in this green solvent under non-demanding experimental conditions. Due to its compatibility to water and to its high versatility, the CMRP process was used for that purpose. The synthetic challenges that we address in this thesis are (1) to perform the CMRP of N-vinyl imidazolium type monomers in water, (2) to prepare hydrosoluble but also amphiphilic all PIL BCPs in this green solvent, and (3) to simplify the process to facilitate its scaling-up. The potential of the innovative PILs developed during this thesis was then explored for applications in energy (as solid electrolytes for battery applications) and environment (as antibacterial coatings/materials). [less ▲]

Detailed reference viewed: 20 (4 ULg)
Full Text
See detailStochastic multi-scale modelling of MEMS
Lucas, Vincent ULg

Doctoral thesis (2016)

When studying Micro-Electro-Mechanical Systems (or MEMS) made of poly-crystalline materials, as the size of the device is only one or two orders of magnitude higher than the size of the grains, the ... [more ▼]

When studying Micro-Electro-Mechanical Systems (or MEMS) made of poly-crystalline materials, as the size of the device is only one or two orders of magnitude higher than the size of the grains, the structural properties exhibit a scatter at the macro-scale due to the existing randomness in the grain size, grain orientation, surface roughness... In order to predict the probabilistic behaviour at the structural scale, we investigated the recourse to a stochastic 3-scale approach in this thesis dissertation. Estimating the scatter in the response of the structure is studied at macro-scale based on stochastic finite elements along with Monte-Carlo simulations. To produce accurate results, the mesh size of the finite element approach should be small enough so that the heterogeneities can be captured. This can lead to overwhelming computation if the microstructure is directly considered, thus justifying the recourse to stochastic homogenisation to define a meso-scale random field. Based on a stochastic model of this random field, the variability of the response of the structure can be computed. In this work, the micro-scale uncertainties are modelled based on measurements provided by the IMT-Bucharest institute. These uncertainties are then propagated towards the macro-scale for 3 different problems. The first one serves the purpose of verification. The variability of the resonance frequency of a micro-beam is computed and compared to a reference numerical solution. The second problem extends the 3-scale approach to the thermo-elastic case. Thus the uncertainties of the quality factor of 3D beams are studied with a modelling of the anchor. Finally, the third problem aims at propagating surface roughness uncertainties on the resonance frequency of thin plates. [less ▲]

Detailed reference viewed: 17 (4 ULg)
Full Text
See detailElectric current crowding effects in microstructured superconductors
Adami, Obaïd-Allah ULg

Doctoral thesis (2016)

Many applications of modern electronic devices are based on thin film geometries including sharp turns, holes and exhibiting inhomogeneities. The inevitable detour of current streamlines around such ... [more ▼]

Many applications of modern electronic devices are based on thin film geometries including sharp turns, holes and exhibiting inhomogeneities. The inevitable detour of current streamlines around such obstacles cause an inhomogeneous current density profile giving rise to current crowding. The goal of my research is to highlight the current crowding effects in micro and nanopatterned superconducting films. [less ▲]

Detailed reference viewed: 44 (12 ULg)
Full Text
See detailEtude des rôles du produit d'expression du gène M138L du virus Myxoma dans la pathogénie de la myxomatose
Boutard, Bérengère ULg

Doctoral thesis (2016)

Myxoma virus belongs to the Poxviridae family and induces a severe and often lethal disease called myxomatosis in the European rabbit (Bertagnoli & Marchandeau, 2015). Numerous genes of the virus encode ... [more ▼]

Myxoma virus belongs to the Poxviridae family and induces a severe and often lethal disease called myxomatosis in the European rabbit (Bertagnoli & Marchandeau, 2015). Numerous genes of the virus encode for proteins with immunomodulatory functions (Spiesschaert et al., 2011; Zuniga, 2002). Among them, it has been demonstrated that the virus encodes for an α-2,3-sialyltransferase (Jackson et al., 1999; Markine-Goriaynoff et al., 2004b) that catalyzes the transfer of sialic acid to the N and O-glycans of glycoproteins and glycolipids (Varki & Schauer, 2009). Glycans, and especially sialic acids, are known to play significant roles in interactions and recognition between cells and between cells and viruses (Cohen & Varki, 2010; Raman et al., 2005; Vigerust & Shepherd, 2007). The aim of this thesis was to better understand the roles played by the viral α-2,3-sialyltransferase in the pathogenesis of myxomatosis. Using the Lausanne strain as parental strain, we have constructed strains deficient for the M138L gene encoding the α-2,3-sialyltransferase, and a revertant strain. Although no difference could be detected between the strains in vitro, the M138L knockout strains were highly attenuated in vivo. Especially, we observed more neutrophils at the beginning of infection and then an important mononuclear cells infiltrate in the dermis of the primary sites of infection for rabbits infected with the M138L knockout strains. We then wanted to determine which viral and / or cellular proteins were affected by the viral α-2,3-sialyltransferase, to check if their modification could explain the phenotype that we observed. We showed that the viral M-T7 protein was sialylated by the viral enzyme. M-T7 is a homologue of the interferon-γ receptor (Mossman et al., 1995) which is also able to bind and inhibit several chemokines, to block the chemokine gradient formation and to inhibit the inflammatory cells attraction towards the site of infection (Alcami, 2003; Lalani et al., 1997). However, we could not detect any effect of sialylation on the secretion or the activity of the M-T7 proteins purified from the four strains, either in vitro or in vivo. Altogether , these results show that the viral α-2,3-sialyltransferase is a virulence factor of the virus that could act directly or indirectly on several immunomodulatory viral proteins, and so on the immune cells attraction and adaptive immunity development. [less ▲]

Detailed reference viewed: 17 (2 ULg)
Full Text
See detailEtude des sémiochimiques volatils impliqués dans le mutualisme fourmis-pucerons
Fischer, Christophe ULg

Doctoral thesis (2016)

For decades, the mutualistic relationship that ant and aphids may present has fascinated entomologists, as evidenced by the abundant literature on the subject. The principles of this interaction are ... [more ▼]

For decades, the mutualistic relationship that ant and aphids may present has fascinated entomologists, as evidenced by the abundant literature on the subject. The principles of this interaction are simple: as long as their colony remains, aphids provide ants with a stable and abundant source of sugars, honeydew. In exchange, ants tend aphid colonies and provide them cleaning and protection against various natural enemies. Nevertheless, some aspects of this relationship remain misunderstood. This is for example the case of the factors influencing the search and the discovery of a potential partner, first step to any potential mutualistic interaction. The role held by volatile chemical cues, called semiochemicals, in this relationship is also misunderstood. The objective of this thesis is to improve understanding of the role played by volatile semiochemicals in this mutualistic relationship, especially during the partner search stage, both from the perspective of the ant and of the aphid. The black garden ant, Lasius niger L., and the black bean aphid, Aphis fabae Scop., constitute our biological model. The impact of volatile compounds on the search behavior of the ant has first been investigated. These compounds are from multiple origins, either directly emitted by the aphid or induced by its presence. First, the ability of ants to perceive E-β-farnesene, the main component of many aphid alarm pheromone, and to use it to locate aphid colonies has been highlighted. This compound has indeed shown attractiveness to ants, even at low doses corresponding to the emissions of an unstressed aphid colony. Then, the roles played by honeydew volatile compounds in ant attraction have been demonstrated. These compounds also allow ants to remotely discriminate different aphid species and to direct their searches accordingly. These semiochemicals are produced by honeydew microflora, and a particularly attractive bacterial strain, Staphylococcus xylosus, has been isolated from A. fabae honeydew. Finally, the active role of winged aphids, which are aphid’s dispersal form, in the search for a mutualistic partner was also studied. Aphids do not appear to be preferentially attracted toward a host plant frequented by ants or close an ant nest. Nevertheless, once a potential host plant reached, they remain longer on it in case of ant presence. This thesis highlights the importance of volatile semiochemicals and honeydew microflora in ant-aphid mutualistic relationships, thus completing by a new aspect an already well documented biological model. [less ▲]

Detailed reference viewed: 21 (4 ULg)
Full Text
See detailDevelopment of innovative and practical management tools to improve sustainability of milk production and quality of dairy products
Arnould, Valérie ULg

Doctoral thesis (2016)

In the current complex economical context, novel strategies are needed to help local dairy farmers to face the European dairy sector crisis. This thesis was initiated in the framework of ManageMilk ... [more ▼]

In the current complex economical context, novel strategies are needed to help local dairy farmers to face the European dairy sector crisis. This thesis was initiated in the framework of ManageMilk project and was globally aimed to investigate the possibility to develop some innovative and practical management tools helping dairy farmers in their daily decisions. To develop such management tools, several conditions must be fulfilled. Firstly, used data must be relevant. According to the literature, the milk composition, and in particular, the milk fatty acid (FA) profile, appears to be a suitable trait allowing useful information about the dairy cow’s health status or about the management system efficiency. These data must also be easily available at low cost from milk recording organization. Recently, the MIR spectrometry offers the possibility to build routinely cheaper and more important databases. To develop management tools, milk samples have to be collected using comparable sampling methods. Unfortunately, in order to decrease the milk quality control costs, the International Committee for Animal Recording allows alternative sampling schemes including the collection of samples from morning or evening only milkings. This alternative sampling scheme can interact with phenotypic and genetic parameters. Therefore, additionally to the development of conversion equations, this thesis is establishing if morning or evening only milkings are genetically different traits. Last condition concerns a useful phenotypic and genetic variability. Milk FA profile is, among others, altered by genetics. So, one paper of this thesis concerns the setup of a useful genetic evaluation model able to estimate accurately the genetic part of milk fat composition variations. Routine genetic evaluation of production traits in dairy cattle commonly uses random regression model (RRM). Recently, “splines” have been advocated as a good alternative to Legendre polynomials (LP) for analyzing test-day yields in RRM. Therefore, several models are compared. Obtained results show the possibility to propose a practical and robust method for estimating accurate daily major FA production from single milking, useful for a further development of practical management tools helping dairy farmers in their daily decisions. [less ▲]

Detailed reference viewed: 40 (4 ULg)
Full Text
See detailMESURES INCITATIVES A LA PRODUCTION COTONNIERE ET PERSPECTIVES DE LA PRIVATISATION DES FILIALES CMDT AU MALI
Koné, Bouréma ULg

Doctoral thesis (2016)

Cotton is the first export crop in Mali with 84,370 billion Fcfa in 2010 (INSTAT, 2010), but the production of this crop has huge problems due to external factors (prices of inputs and seed cotton) and ... [more ▼]

Cotton is the first export crop in Mali with 84,370 billion Fcfa in 2010 (INSTAT, 2010), but the production of this crop has huge problems due to external factors (prices of inputs and seed cotton) and internal (within payment to producers, internal debts of cooperatives). To boost cotton production during the years 2010/11 and 2011/12, the government had maintained the level of fertilizer subsidy at 50% of normal price on the market. In addition to this level of subsidy, the incentive price of 255Fcfa / kg was fixed to the producer and the National Union of Cotton Producers Cooperative Societies (NU-CPCS) facilitated the clearance of the internal debts of cooperatives. Despite the fall in world prices after 2011/12, the price of cotton seed remains little changed. The price stayed at 255 CFA francs / kg in 2012/13 and got back to 250 CFA francs / kg in 2013/14. The objective of this work is to analyze the effects of incentives factors cotton production with a view to the privatization of CMDT subsidiaries Surveys were conducted with a sample of 240 farms selected from the four zones of the CMDT zones based on two villages subsidiary during the years of 2008/09, 2010/11 and 2011/12. The results showed a positive trend in production (mainly due to an increase in the area) and in the income of cotton producers with a higher reimbursement rate of input credits under cultivation. The analysis of the Domestic Resource Cost (DRC) the Nominal protection coefficients (NPC) and the Effective (CPE) showed an improvement in thèse variables in 2011/12 with the incentive policy. An analysis of the determinants of the supply of cotton showed that only two variables were significant: the price cottonseed and payment period. The incentive factors are influenced by fiber market in 2011/12 which took a downward trend from the campaign. This incentive policy being favored by the market of fiber which is very unstable, it would be necessary to create conditions in which the producer can benefit from the price obtained on the quality of fiber to maintain the incentive policy for producers. For the privatization of Cotton Company, an upgrade of this company is necessary with the support of the Malian state. But this upgrade should not affect too much the selling price of sale of cotton that can bring new companies in a situation of too long term recovery of capital invested (long period of investment recovery). The privatization scheme as presented makes major companies more competitive. In order to reduce the operating costs a form of collaborative relationships among delivery companies would be required. Keywords: fertilizer subsidy, incentive price, cotton sector in Mali, privatization subsidiary, competitiveness. [less ▲]

Detailed reference viewed: 18 (4 ULg)
Full Text
See detailANALYSE DE LA DEMANDE EN CHARBON DE BOIS PAR LES MÉNAGES URBAINS DE BUJUMBURA AU BURUNDI
Sabuhungu, Emery Gaspard ULg

Doctoral thesis (2016)

The objective of this study is to evaluate the demand for charcoal by urban households in Bujumbura in order to make recommendations ensuring the security of household energy and environmental protection ... [more ▼]

The objective of this study is to evaluate the demand for charcoal by urban households in Bujumbura in order to make recommendations ensuring the security of household energy and environmental protection. To achieve this objective, the analysis of the related documentation and collection of secondary data were carried out in order to formulate specific objectives, hypotheses and the methodology used in the course of this study. The specific objectives are: to analyze the structure, operation and market performance of the charcoal market in the city of Bujumbura and to compare this market to the cities of Lubumbashi and Kigali; to determine the charcoal consumption pattern by urban households in Bujumbura; to identify the factors which influence the demand for charcoal by urban households in Bujumbura; to evaluate the demand for charcoal by urban households in Bujumbura. The assumptions made in this study are: the charcoal market in the city of Bujumbura is a competitive and effective market; charcoal is the dominating cooking fuel used by urban households in Bujumbura and is consumed exclusively or in combination with others; an urban household’s demand for charcoal in Bujumbura is essentially based on household income, the size of household, eating habits (preparation of food that requires a long cooking time), the frequency of use of carbon and the possession or not of improved cooking stoves; the demand for charcoal by urban households in Bujumbura is high and this leads to significant annual deforestation. Three surveys were conducted to collect primary data. The first survey, with the specific objective of analysing the charcoal market in Bujumbura, was conducted among the key players of the charcoal value chain produced in the communes of Mugamba and Muramvya and consumed in the city of Bujumbura. The remaining two surveys, with the specific objective of analysing the consumption of charcoal by households, were conducted among households-users of charcoal of different standards of living in three areas of the city of Bujumbura (areas Buterere, Cibitoke and Rohero). The results indicate that the charcoal market is competitive. The production, the commercialisation and the consumption of charcoal allow the creation of positive value added all along the charcoal value chain. The use of cooking fuels by households in Bujumbura shows that they have not yet achieved an energy transition. In fact, 83% of those surveyed only use charcoal; 12% combine charcoal and electricity and 5% combine charcoal and firewood. The results revealed that the main factors influencing households demand for charcoal are: household income, the price of charcoal, household size, number of cooking sessions per day, frequency of preparation of cassava leaves and the possession or not of improved braziers. To solve the energy and environmental problem, a rehabilitation of woodland, an implementation of the best techniques of woodland planting with the most adaptable species on productive land, a greater penetration of substitutable energy to wood fuel such as gas or electricity, a growth in the use of improved cooking stoves in households and greater efficiency in wood carbonisation will help reduce the number of hectares of deforestation for wood energy needs. [less ▲]

Detailed reference viewed: 30 (10 ULg)
Full Text
See detailThe Chemistry of New Garlic-Derived Organosulfur Compounds and the Molecular Basis of Olfaction »
Dethier, Bérénice ULg

Doctoral thesis (2016)

Garlic is a very popular condiment that has been used around the world for centuries. It is also a source of a remarkably extensive range of organosulfur compounds, whose chemistry is the focus of this ... [more ▼]

Garlic is a very popular condiment that has been used around the world for centuries. It is also a source of a remarkably extensive range of organosulfur compounds, whose chemistry is the focus of this thesis. The central reaction in formation of these compounds is the enzymatic cleavage of alk(en)yl cysteine sulfoxides by alliinases, which leads to sulfenic acids. The latter can then undergo condensation and rearrangement into various organosulfur compounds. Three aspects of the chemistry of garlic have been investigated in this thesis. First, little studied, minor organosulfur compounds in extracts of freshly chopped garlic were studied. These higher molecular weight compounds (MW 150–550) can be conveniently studied using state-of-the-art Liquid Chromatography-Mass Spectrometry (LC-MS) and Direct Analysis in Real Time-Mass Spectrometry (DART-MS) techniques. Novel garlic-derived compounds were studied and the structure of one representative compound containing a five-membered thiolane ring, ajothiolane, was determined by spectroscopic methods, using synthetic analogues as spectroscopic standards. The fate of compounds in a garlic extract over time was also studied, since the new, higher mass sulfur compounds are slowly formed by rearrangement of smaller metabolites a few days after maceration of the garlic. A second part of this thesis provides hands-on methods for the analysis and preparation of key garlic metabolites. The isolation and/or synthesis of alliin, alliinase and vinyldithiins have been optimized, and are proposed as turnkey procedures for future work. Finally, in an effort to explain the unique odor of garlic-related thiols and sulfides (in garlic breath, sweat, etc.), the interactions between odorants and olfactory receptors have been studied. Work described in this thesis contributed to this larger project by designing and synthesizing model macrocyclic odorants to resolve the mechanism of olfaction at the receptor level. The conclusions, arguing against the plausibility of the so-called “vibration theory of olfaction”, have been published as a foundation for future work on olfactory detection of thiols and other sulfur-containing compounds. [less ▲]

Detailed reference viewed: 38 (4 ULg)
Full Text
See detailCanine idiopathic pulmonary fibrosis : improvement of the phenotype characterization and search for biomarkers and for etiologic agents
Roels, Elodie ULg

Doctoral thesis (2016)

Canine idiopathic pulmonary fibrosis (CIPF) is a progressive parenchymal lung disease of unknown origin, mainly described in old-aged West Highland white terriers (WHWTs). It is characterized by exercise ... [more ▼]

Canine idiopathic pulmonary fibrosis (CIPF) is a progressive parenchymal lung disease of unknown origin, mainly described in old-aged West Highland white terriers (WHWTs). It is characterized by exercise intolerance, cough and dyspnoea/tachypnea with a progressive deterioration until death from respiratory insufficiency. CIPF shares clinical features with human idiopathic pulmonary fibrosis (IPF), while tomodensitometric and histopathological findings do not appear to be exactly the same. Over the past 10 years, several studies have been performed to improve our knowledge about CIPF. However, this disease is still misunderstood and clinicians are dealing with several challenges including the absence of clinical or biological markers for estimating the presence, severity or progression of the disease and related comorbidities such as pulmonary hypertension, the absence of etiologic agent, and the absence of targeted therapy. Consequently, the aims of the present project were (1) to investigate whether high-resolution computed tomography (HRCT) of the lungs obtained under sedation can be used for the diagnosis and for the follow-up of the disease, (2) to study a new echocardiographic parameter for the diagnosis of precapillary pulmonary hypertension induced by CIPF, (3) to study the potential roles of 2 chemokines of interest, CCL2 and CXCL8, as biomarkers of fibrosis and as actors in the pathogenesis of the disease, (4) to determine breed variation of basal blood concentrations of the same chemokines, vascular endothelial growth factor (VEGF), and serotonin, and (5) to search for the presence of herpesvirus as a possible etiologic agent. [less ▲]

Detailed reference viewed: 16 (3 ULg)
Full Text
See detailClostridium difficile a new zoonotic agent? Assessment of human transmission potential of hypervirulent strains of Clostridium difficile through food products consumption
Rodriguez Diaz, Cristina ULg

Doctoral thesis (2016)

Clostridium difficile is a spore-forming anaerobic bacterium recognised as a major human pathogen responsible for pseudomembranous colitis and nosocomial-antibiotic associated diarrhea. Traditionally ... [more ▼]

Clostridium difficile is a spore-forming anaerobic bacterium recognised as a major human pathogen responsible for pseudomembranous colitis and nosocomial-antibiotic associated diarrhea. Traditionally, hospitals were considered the main reservoirs for infection. However, in the last years the incidence, deaths, complications and costs of C. difficile infection (CDI) have been rising, not only in healthcare facilities, but also within the community. In the community, it has been detected in a growing number of CDI cases in previously healthy individuals without antimicrobial exposure, hospital stay or any other classical risk factors. Furthermore, the disease has been repeatedly described in younger patients, including children. Some hypotheses have been proposed to explain this peak of community cases, the most obvious being that nowadays more attention is given to CDI surveillance. In the last years, diarrhea due to C. difficile disease might have gone undiagnosed, and in many cases went unreported, particularly in the community. Since 2004, severe outbreaks of CDI have been documented increasingly in the United States, Canada and in Europe. These outbreaks have been associated with the emergence of a novel strain, known as PCR-ribotype 027, characterised by higher than usual levels of toxins A and B production, and the presence of a third toxin named CDT or binary toxin. This strain type is also characterised by its resistance to both erythromycin and fluoroquinolones (i.e. moxifloxacin, gatifloxacin and levofloxacin). However, according to the latest hospital surveillance studies in Europe, since 2010 there is a decrease in the incidence rates of PCR-ribotype 027 while other PCR-ribotypes, including PCR-ribotypes 014, 020, 001, 002, 078 and 015 are increasing. Person to person contact is one source proposed for the spread in the community, occurring after visiting hospitalised patients or residents in long-term care facilities. Employees of these health-care settings can also carry spores and contaminate their entourage. The second hypothesis is contamination from the environment, following visits to a potentially contaminated place, such as hospitals or nursing homes. The two most important potential sources of CDI in the community, which have been demonstrated by investigations in the last decade are animals and foods. While C. difficile is also known as enteric pathogen in some food producing and companion animal species, there are several reports describing the presence of the bacterium in the intestinal contents of apparently healthy animals. Moreover, data published recently suggests animals as an important source of human CDI, which can spread disease through environmental contamination, direct or indirect contact, or food contamination, including carcass and meat contamination at slaughter or in the case of crops, through the use of organic animal manure. By definition, zoonoses are infectious diseases that can be transmitted directly or indirectly between animals and humans, through direct contact or close proximity with infected animals, or through the environment. Foodborne zoonotic pathogens are transmitted via the consumption of contaminated food or drink water. The first description of C. difficile in domestic animals and their environments dates from 1974 and possible foodborne transmission was reported for the first time in 1982. However, nowadays the importance of C. difficile as zoonotic disease remains largely unknown. The "One Health" concept is a worldwide strategy, which recognises that the health of humans and animals is connected and also depends on the environment. The present dissertation is a 5 year national study that has investigated the presence of C. difficile in animals and food, from “farm-totable”. The study was also extended to humans resident in a nursing home and in two hospitals in Belgium and in Spain. The characterisation of the isolates obtained has ultimately allowed comparison of the PCR-ribotype distribution in the different European hospitals, as well as with the PCR-ribotype distribution found in animals and foods. This work explores how C. difficile spreads among human patients, animals, foods and the environment to better understand the potential of the bacterium as a zoonotic or foodborne infectious agent. [less ▲]

Detailed reference viewed: 103 (3 ULg)
See detailFrom Statistical to Biological Interactions via Omics Integration
Bessonov, Kyrylo ULg

Doctoral thesis (2016)

The XXI century opened a new ‘Big Data’ era in which, thanks to rapid technological advancements and appearance of high throughput technologies, vast amounts of omics data (e.g., transcriptomic, genomic ... [more ▼]

The XXI century opened a new ‘Big Data’ era in which, thanks to rapid technological advancements and appearance of high throughput technologies, vast amounts of omics data (e.g., transcriptomic, genomic, etc.) are generated every day. This thesis mainly focuses on solving the problems related diverse omics data integration and interaction identification tasks. Particular attention is given to useful knowledge extraction in the context of complex diseases including pathological mechanisms with the development of software tools and pipelines. The diseases covered included glioblastoma multiforme, asthma, and ankylosing spondylitis. Interactions detection in genomic data requires standardization of the protocols. In Chapter 3, we tested the impact of different settings in a genome-wide association interaction (GWAI) study. Some of the settings included marker selection strategy, the LD pruning, lower order effects adjustment, analytical tool. We were able to show that even small changes in each setting can have drastic impacts requiring careful assessment of proper settings and results comparisons across several analysis protocols. The greatest impact was attributed to the input dataset composition highlighting the importance of the marker selection strategy and use of prior knowledge. Expression of genes can be affected by nearby (‘cis’) or distant (‘trans’) genotypes. Thus, we developed methodology to identify complex trans/cis regulatory mechanisms between expression and genotype data in the context of asthma (CAMP data). Significant overlap between ‘trans’ and ‘cis’ gene regulatory components related to immune and signaling pathways was clearly identified matching asthma disease pathology. The semi-parametric Model-Based Multifactor Dimensionality Reduction (MB-MDR) method was applied for the first time in the context eQTL study achieving low false discovery and family-wise error rates (FDR and FWER). Identification of a meaningful data structure from omics data is a pressing topic nowadays. Gene regulatory networks (GRN) conveniently summarize large amounts of data allowing for useful knowledge generation. GRN inference is especially attractive for deciphering of complex diseases mechanisms allowing biologists to formulate a better hypothesis. We were able to generate GRNs from a single source (e.g., microarray expression data) using conditional inference forest (CIF) with more attractive features compared to classical Random-Forest (RF) including unbiased node variable selection even in the context of highly correlated variables particularly relevant in transcriptomics. The CIF methods provided attractive features and performance characteristics coupled to valuable pathological insights into type 1 diabetes. [less ▲]

Detailed reference viewed: 48 (6 ULg)
Full Text
See detailCONTRIBUTION A L’ETUDE DE L’ECHOGRAPHIE INTERVENTIONNELLE DU RACHIS CHEZ LE CHIEN : MISE AU POINT DE TECHNIQUES ECHOGUIDEES POUR LES PONCTIONS SOUS-ARACHNOÏDIENNES ET ANALYSE DE LEUR APPLICATION
Etienne, Anne-Laure ULg

Doctoral thesis (2016)

SUMMARY Percutaneous ultrasound guidance has become a routine procedure in veterinary medicine in domestic animals. It allows precise placement of the needle in the desired target. Punctures of the ... [more ▼]

SUMMARY Percutaneous ultrasound guidance has become a routine procedure in veterinary medicine in domestic animals. It allows precise placement of the needle in the desired target. Punctures of the subarachnoid space in dogs are frequently carried out in veterinary practice for diagnostic purposes. In these procedures, the placement of the needle into the subarachnoid space (atlanto-occipital or lumbar) is commonly performed blindly by feeling the bony anatomical landmarks but this can be laborious or even impossible in some patients as reported in human medicine. The topic of this study is ultrasound guidance for the placement of the needle during puncture of the subarachnoid space. The needle placement can be done under ultrasound guidance according to two methods. The "indirect guidance" is a method of deferred ultrasound guidance. The "direct guidance" is a real time procedure in which the operator holds the needle in one hand and the ultrasound probe in the other. It allows direct visualization of the needle (if direct guidance), the target structure, adjacent tissues (including vascular structures) and potential injectate while minimizing the risk of complications. Punctures of the subarachnoid space are carried out by placing the needle in the cisterna magna or in the caudal lumbar subarachnoid space (between the fifth and sixth lumbar vertebrae). The cisternal puncture is most frequently used in practice but presents greater risk of iatrogenic lesions of the brain stem. The lumbar puncture is technically more difficult and is frequently contaminated by iatrogenic blood. Cerebrospinal fluid punctures have several clinical applications. They allow to collect cerebrospinal fluid for diagnostic testing, to realize myelograms or myeloscanners by injecting contrast medium and to perform spinal anesthesia or analgesia by injecting one or more substance(s) blocking the conduction of the spinal nerves. Subarachnoid lumbar puncture is used commonly in the dog for cerebrospinal fluid collection and/or myelography. Percutaneous ultrasound anatomy of the lumbar region in the dog and a technique for ultrasound-guided lumbar puncture were described in the first study. Ultrasound images obtained ex- vivo and in-vivo were compared with anatomic sections and used to identify the landmarks for ultrasound-guided lumbar puncture. The ultrasound-guided procedure was established on cadavers and then applied in-vivo on eight dogs. The anatomic landmarks for the ultrasound-guided puncture, which should be identified using the parasagittal oblique ultrasound image, were the articular processes of the fifth and sixth lumbar vertebrae and the interarcuate space. The spinal needle was directed under direct ultrasound-guidance toward the triangular space located between the contiguous articular processes of the fifth and sixth lumbar vertebrae and then advanced to enter the vertebral canal. Using these precise ultrasound anatomic landmarks, an ultrasound-guided technique for lumbar puncture is applicable to dogs. Cisternal puncture in dogs and cats is commonly carried out. Percutaneous ultrasound anatomy of the cisternal region in the dog and the cat and an indirect technique for ultrasound-guided cisternal puncture were described in the second study. Ultrasound images obtained ex-vivo and in-vivo were compared with anatomic sections and used to identify the landmarks for ultrasound-guided cisternal puncture. The ultrasound-guided procedure was established in cadavers and then applied in- vivo in seven dogs and two cats. The anatomic landmarks for the ultrasound-guided puncture were the cisterna magna, the spinal cord, the two occipital condyles on transverse images, the external occipital crest and the dorsal arch of the first cervical vertebra on longitudinal images. Using these ultrasound anatomic landmarks, an indirect ultrasound-guided technique for cisternal puncture is applicable to dogs and cats. The standard technique for placing a needle into the canine lumbar subarachnoid space is primarily based on the palpation of anatomic landmarks and the use of probing movements of the needle. However, this technique can be challenging for novice operators. The aim of the third observational, prospective, ex vivo, feasibility study was to compare ultrasound-guided versus standard anatomic landmark approaches for novices performing needle placement into the lumbar subarachnoid space using dog cadavers. Eight experienced operators validated the canine cadaver model as usable for training landmark and ultrasound-guided needle placement into the lumbar subarachnoid space based on realistic anatomy and tissue consistency. With informed consent, 67 final year veterinary students were prospectively enrolled in the study. Students had no prior experience in needle placement into the lumbar subarachnoid space nor use of ultrasound. Each student received a short theoretical training about each technique before the trial and then attempted blind landmark-guided and ultrasound-guided techniques on randomized canine cadavers. After having performed both procedures, the operators completed a self-evaluation questionnaire about their performance and self-confidence. Total success rates for students were 48% and 77% for the landmark- and ultrasound-guided technique, respectively. Ultrasound guidance significantly increased total success rate when compared to the landmark-guided technique and significantly reduced the number of attempts. With ultrasound guidance self-confidence was improved, without bringing any significant change in duration of the needle placement procedure. Findings indicated that the use of ultrasound guidance and cadavers is a feasible method for training novice operators in needle placement into the canine lumbar subarachnoid space after short theoretical training. Ultrasound-guided techniques for needle placement in the cisterna magna and in the lumbar subarachnoid space were described in the dog. The aim of the fourth observational, prospective, ex-vivo study was to compare the impact of ultrasound guidance for the cisternal versus lumbar needle placement using dog cadavers. With informed consent, 83 operators were prospectively enrolled in the study. They were divided in four groups depending on experience. Each operator received a short theoretical training about each technique before the trial and then attempted a cisternal and lumbar punctures with blind landmark-guided and ultrasound-guided techniques on randomized canine cadavers. The lumbar ultrasound-guidance was direct while the cisternal ultrasound-guidance was indirect. After having performed each procedure, the operators completed a self-evaluation questionnaire about their previous experience, their performance and their self-confidence. The ultrasound guidance significantly increased total success rate in both areas compared with the blind technique but more significantly in the lumbar region. The cisternal ultrasound guidance significantly improved the number of attempts, the time needed to perform the procedure and the self-confidence in inexperienced and experienced operators. The lumbar ultrasound guidance significantly increased the self-confidence in inexperienced and experienced operators and significantly decreased the number of attempts in inexperienced operators. The first cause of failure cited was different according to the location of the puncture and was related to the nature of ultrasound guidance. Findings indicated that the use of ultrasound guidance by novice and experienced operators improved different parameters according to the location of the needle placement. This study demonstrated that inexperienced operators are able to use ultrasound guidance after a short theoretical teaching session in an ex-vivo context and this supports the use of ultrasound-guidance for learning and teaching purposes. The study of the impact of ultrasound guidance for needle placement procedures described in this work could be developed and studied for other technically difficult or risky procedures on dogs. If the benefits of ultrasound guidance demonstrated ex-vivo in this work are transferable to the clinical conditions, punctures of the subarachnoid injections would be less « scary » for novice operators and become routine procedures applicable by a large numbers of veterinarians. [less ▲]

Detailed reference viewed: 17 (0 ULg)
Full Text
See detail"Saisir l'État". Les conflits d’héritage, la justice et la place du droit à Cotonou.
Andreetta, Sophie ULg

Doctoral thesis (2016)

Tout comme de nombreux autres États sur le continent africain, le Bénin a entrepris, à partir des années 1990, une large réforme de ses services publics dans laquelle la justice occupe une place centrale ... [more ▼]

Tout comme de nombreux autres États sur le continent africain, le Bénin a entrepris, à partir des années 1990, une large réforme de ses services publics dans laquelle la justice occupe une place centrale. Parmi les premiers textes à faire l’objet d’une révision figure le Code des personnes et de la famille, censé promouvoir l’égalité des sexes, contrairement au droit « coutumier » jusque-là applicable à la majorité des familles. Avec les conflits d’héritage comme porte d’entrée, cette recherche avait pour objectif de réfléchir à l’appropriation de ce nouveau texte par différents types d’acteurs. En effet, les questions liées à la gestion et à la répartition de l’héritage sont fréquemment source de conflits à Cotonou et dans les localités voisines. De nombreuses familles saisissent les cours et tribunaux. Dans un contexte où les services publics sont souvent associés à la corruption et aux pratiques informelles, cette thèse envisage les spécificités du système judicaire béninois, la question de la place du droit pour les citoyens, dans le travail des juges et le fonctionnement des tribunaux, démontrant ainsi que les règles officielles sont loin d’être systématiquement contournées dans les administrations africaines. [less ▲]

Detailed reference viewed: 57 (13 ULg)
Full Text
See detailGlobal changes, human activities and (re-) emerging of mosquito-borne pathogens: diversity, ecology and control of potential vectors
Boukraa, Slimane ULg

Doctoral thesis (2016)

Worldwide, mosquitoes (Diptera: Culicidae) are known as potential vectors of pathogens that cause infectious diseases, affecting both humans and animals, such as malaria, dengue, chikungunya, West Nile ... [more ▼]

Worldwide, mosquitoes (Diptera: Culicidae) are known as potential vectors of pathogens that cause infectious diseases, affecting both humans and animals, such as malaria, dengue, chikungunya, West Nile fever and dirofilariasis. In terms of morbidity and mortality, mosquitoes are considered as the most dangerous animals confronting mankind. Indeed, over three billion people live at risk of becoming infected by a mosquito-borne disease. Focus on mosquitoes has greatly increased not only in the tropic areas but also in the Palearctic region like Europe and Mediterranean areas. Researches on re-emerging vector-borne diseases are become a major issue in human and animal health worldwide, both in the North and South hemisphere. The spread in space and time of these many vector-borne diseases is strongly influenced by environmental factors (landscape, location and abundance of hosts and vectors, etc.) and climate (temperature, humidity, etc.) that influence population dynamics of the vector and the reservoir hots of pathogens. The acquisition of bio-ecological and taxonomic knowledges of mosquitoes is nevertheless an essential step for the understanding, preventing and management of current risks of the (re)-emergence of mosquito-borne parasites and mainly the preparation and prevention against future threats. The absence of vaccine and treatments against most of mosquito-borne diseases implies efficient vector control strategies, which are up to date mainly based on the use of chemical insecticides. However, most vectors develop resistance against currently used products whereas new chemical compounds was limited firstly by financial costs in research and development, and secondly by the toxicity of derivatives to human population, biodiversity, and environment. The exploitation of new methods, such as the use of microbial communities (mainly bacteria or entomopathogenic fungi) for vector control, will be therefore a promoted strategy at the global level. This doctoral thesis focuses on five main objectives: (i) to inventory and identify mosquito fauna in the livestock areas and their surroundings, especially in the equestrian farms; (ii) to study the population genetic structure of the potential vector complex Cx. pipiens s.l.; iii) to study the phylogeny and the origin of exotic mosquito species (Ae. albopictus & Ae. koreicus) as well as the potential tracks of their introduction; (iv) to know the bioecology and spatiotemporal dynamic of potential vectors; and finally (v) to suggest a biocontrol tool that can prevent and fight the proliferation of mosquitoes especially potential vectors and those causing nuisance problems. Obtained results in this thesis allowed highlighting identification and record of new mosquito species in the studied areas. It also allowed updating the list of mosquito fauna in the two countries, Belgium (31 species including three invasive mosquitoes) and Algeria (53 species including four new records form this research: Culex brumpti, Coquillettidia richiardii, Cq. Buxtoni and Uranotaenia balfouri). The phylogenetic analyses (COI and ND4) performed during this thesis allowed to confirm that Aedes koreicus and Ae. japonicas complex constitute two distinct species. In addition, given the phylogenetic analyses (COI and ND5 genes) and information about the origin of used tires inspected during this study in Belgium, Ae. albopictus was very probably reintroduced from the United States. In both Belgium and Algeria, this work permitted identifying and confirming the presence of different molecular forms of the Cx. pipiens complex: Cx. pipiens form pipiens, Cx. pipiens f. molestus as well as their hybrid form. Medical and veterinary importance of identified mosquito species and the risk of (re-)emerging of mosquito-borne diseases in Belgium and Algeria are discussed. Finally, the endosymbiont bacteria Pseudomonas seemed to be an interesting candidate for paratransgenic bacteria in order to reduce and/or inhibit the transmission of pathogens by mosquito vectors. [less ▲]

Detailed reference viewed: 188 (5 ULg)
Full Text
See detailCaractérisation phénotypique, morphologique et fonctionnelle des éosinophiles résidents du poumon
Raulier, Stéfanie ULg

Doctoral thesis (2016)

Eosinophils have long been considered as destructive effector cells implicated in parasitic infections and allergic reactions such as asthma. This traditional restrictive view of eosinophils has now been ... [more ▼]

Eosinophils have long been considered as destructive effector cells implicated in parasitic infections and allergic reactions such as asthma. This traditional restrictive view of eosinophils has now been considerably extended. Indeed, beside their pro-inflammatory functions, eosinophils are also able to finely shape local innate and adaptative immune responses. Moreover, recent studies indicate that steady-state resident eosinophils are now thought to contribute to immune homeostasis at mucosal sites such as the gut. In the normal lung, resident eosinophils (rEOS) have been little-studied so far. Here, we report that in mice, steady-state pulmonary rEOS are parenchymal Siglec-Fint CD125int cells characterized by a ring-shaped nucleus. [less ▲]

Detailed reference viewed: 27 (4 ULg)
Full Text
See detailVers une transition durable des quartiers urbains. Formulation d'un modèle d'innovation applicable à la politique des quartiers.
Ruelle, Christine ULg

Doctoral thesis (2016)

La thèse démontre que la transition durable se produit de manière très inégale dans les quartiers urbains. Elle explore alors la question de l'action publique et de la manière dont les pouvoirs publics ... [more ▼]

La thèse démontre que la transition durable se produit de manière très inégale dans les quartiers urbains. Elle explore alors la question de l'action publique et de la manière dont les pouvoirs publics pourraient soutenir cette transition durable dans les quartiers. En particulier, le potentiel de la "politique des quartiers" est analysé et des amélioration sont proposées. La recherche-action est ensuite mobilisée pour pour enrichir cette politique de nouveaux instruments d'action, plus adaptés pour engager les habitants dans la dynamique de transition durable de leur quartier. [less ▲]

Detailed reference viewed: 40 (7 ULg)
Full Text
See detailNumerical Assessment of Non-Lethal Projectile Thoracic Impacts
Nsiampa Ndompetelo, ULg

Doctoral thesis (2016)

Anti-personnel Non-Lethal Weapons (NLW) are weapons that are designed to impart sufficient effect onto a person in order to deter uncivil, suspect or hazardous behaviour with a low probability of severe ... [more ▼]

Anti-personnel Non-Lethal Weapons (NLW) are weapons that are designed to impart sufficient effect onto a person in order to deter uncivil, suspect or hazardous behaviour with a low probability of severe or fatal injury. They are used both by military and law enforcement in situations of low-intensity conflicts like riot control, access denial, peacekeeping missions i.e. situations where the use of lethal force is not appropriate nor desired. The most used of these weapons are the Kinetic Energy Non-Lethal Weapons (KENLW). The underlying principle of KENLW is to launch a projectile with a mass varying between 5 g and 140 g at initial velocity up to 160 m/s, which by a mechanical action on the target, will cause enough physical pain to incapacitate or repel the target. But their use is not without risk as in practice, the impacts of Kinetic Energy Non-Lethal (KENL) projectiles on the human thorax resulted in injuries, some of the them were severe even fatal. Therefore there is a need to develop methods of assessment. These assessment methods are essential in order to help deciders in charge of non- lethal weapon procurement with technical information so they can choose the best product (weapon or projectile) available on the market; to give relevant information to the manufacturers in either developing new weapons or projectiles that are more effective, or improving the existing ones, and finally to the end-users (military or police forces) of these weapons, information on operational distance of engagement. In practice, it has been observed that the thorax is the body region where the impacts of KNL projectiles led to more significant injuries than other parts of the body apart from the head which is never targeted at. Therefore in the present thesis, only assessment of thoracic impacts is investigated. Besides tests on PMHS (Post Mortem Human Subjects), animals or human surrogates, one powerful tool that is used nowadays to assess the thoracic impacts is the finite element method (FEM). It has many advantages like the capability of accounting for complex geometries or complex material modelling and its cost-effectiveness. It also gives insight into physical variables (stresses, strains,...) inside the material which are inaccessible by other means. It helps for a better understanding of the injury mechanism. Moreover, it helps to reduce cadavers or animal testings. In the present thesis, only FEM is considered as tool for injury risk assessment. On the one hand, a thorax finite element (FE) model, the SHTIM (Surrogate Human Thorax Impact Model) has been developed for the injury risk assessment. Number of assumptions has been made relative to the thorax geometry and the material characteristics are based on literature. The model has been validated thanks to the results of experiments carried out by professor C. Bir. A viscous injury criterion was defined as the parameter relevant for the occurrence of the thorax skeletal injury. This criterion is used in the present thesis for the prediction of the thoracic injury outcome. On the other hand, FE models of six projectiles have been developed where most of material characteristics were taken from the literature. For the 40 mm sponge grenades, a new method of characterizing the deformable nose has been developed. The projectile FE models were validated by comparing numerical results to experimental results obtained from real firing tests of the projectile against a rigid wall structure. These firing tests have been performed within the Department ABAL. Good correspondence was found. Once the thorax FE model and the projectile FE models validated, numerical simulations of the impact between the thorax and the projectile were performed. Using the viscous injury criterion, risk assessment of the thorax impacts was carried out. For each projectile, a critical velocity was determined which thanks to the retardation can be linked to a minimum firing distance, the safe distance. This is the distance below which an impact will result in a higher risk of skeletal thoracic injury. This information is very important for the end-users (military, police). Moreover comparison of the performance of different KENL projectiles was carried out. Few years ago, the Department ABAL acquired a thorax mechanical surrogate, the 3RBID (3 Rib Ballistic Impact Dummy) for the prediction of thoracic injury. It was an opportunity to compare both surrogates and to see if the SHTIM results are consistent with the 3RBID results. Good correspondence has been found especially for projectiles with larger diameter like the 40 mm sponge grenades. [less ▲]

Detailed reference viewed: 21 (1 ULg)
See detailCell death signaling in cancer cells treated by Photodynamic Therapy
Fettweis, Grégory ULg

Doctoral thesis (2016)

Glioblastoma multiformes (GBMs) are an extremely aggressive and infiltrating type of brain cancer. Despite heavy therapies and extensive fundamental and applied research, the median survival of patients ... [more ▼]

Glioblastoma multiformes (GBMs) are an extremely aggressive and infiltrating type of brain cancer. Despite heavy therapies and extensive fundamental and applied research, the median survival of patients remains about 15 months after diagnosis for over a decade. Therefore, there is an emergency to find new approaches and therapeutic targets for treating this cancer. Photodynamic therapy (PDT) recently demonstrated a high potential in the treatment of GBM. Moreover, GBMs induced cell death by PDT is dependent of an atypical RIP3-dependent programmed necrosis. In parallel, GBMs activate a pro-survival autophagic pathway in order to recycle PDT-damaged structures and organelles. In our PhD thesis, we investigated the regulation of this autophagic process and found that TSC2 protein had an important role in autophagy activation by PDT. Indeed, PDT treatment quickly activates the kinase MK2, which phosphorylates TSC2 on serine 1254. We then showed that phosphorylation of this serine was crucial for autophagy activation, which makes TSC2 a crucial pro-survival factor in GBMs treated with PDT. Finally, we demonstrated that protein 14-3-3 ζ (YWHAZ) interacts with TSC2 and protects TSC2 serine 1254 phosphorylation from phosphatase actions after PDT. In the same time we conducted a proteomic analysis on RIP3 immunoprecipitate. The major implication of this analysis is the demonstration that RIP3 interacts with TSC2 and YWHAZ. Finally, we showed that RIP3 interacts better with the non-phosphorylated form of TSC2 than with the phosphorylated form, suggesting a RIP3 interference in the TSC2-dependent autophagy activation process. These data were submitted for publication in "Scientific Reports". In the second part of this thesis, we also investigated the influence of RIP3 expression on osteosarcoma (U2OS) cell death. U2OS expressing or not RIP3 were treated with PDT and cell death mechanisms have been investigated. We first demonstrated that in both cell lines, apoptosis was the major cell death mechanism. Secondly, we noticed an over-activation of various caspases in cells expressing RIP3 despite a stronger resistance to PDT. This could be explained by a lower activation of autophagy in cells not expressing RIP3. Thirdly, we showed that in RIP3 expressing cells, residual necrosis was RIP1-dependent. We therefore suggest that RIP3 is able to influence the cell death process. These data were published in "Laser in surgery and medicine." [less ▲]

Detailed reference viewed: 5 (3 ULg)
Full Text
See detailOn Generalized Hölder-Zygmund Spaces
Kreit, Damien ULg

Doctoral thesis (2016)

To study the regularity of functions, many functional spaces have been introduced during the 20th century. Among them, let us mention the Hölder-Zygmund spaces \Lambda^{\alpha}(\R^{d}) and the Besov ... [more ▼]

To study the regularity of functions, many functional spaces have been introduced during the 20th century. Among them, let us mention the Hölder-Zygmund spaces \Lambda^{\alpha}(\R^{d}) and the Besov spaces B_{p,q}^{\alpha}(\R^{d}) where \alpha>0 somehow indicates the regularity of their elements (p,q\in ]0,+\infty]). The Hölder-Zygmund spaces are particular cases of Besov spaces in the sense that \Lambda^{\alpha}(\R^{d})=B_{\infty,\infty}^{\alpha}(\R^{d}). A generalization of Besov spaces has been introduced in the middle of the seventies and is still studied nowadays. This new type of space allows a deepest study of the regularity of functions. In this thesis, we start from this generalization in order to introduce a generalization of Hölder-Zygmund spaces. The first aim of this thesis is to show that most classical properties of Hölder-Zygmund spaces can be transposed to their generalized version. Among others, a complete characterization of these spaces in terms of wavelet coefficients is proved, which opens their use in the context of the signal analysis. The second aim of this thesis is to introduce a generalized version of the pointwise Hölder spaces similarly to their global version. We then show that most properties of the global spaces can be transposed to their generalized pointwise version. Finally, we study the regularity of some financial stochastic processes. [less ▲]

Detailed reference viewed: 28 (8 ULg)
Full Text
See detailInfluence du conditionnement et de la déshydratation mécanique sur le séchage des boues d'épuration
Pambou, Yvon-Bert ULg

Doctoral thesis (2016)

Wastewater treatment plants generate a byproduct which is found in the form of a colloidal suspension, known under the generic term of sludge. At present time, its valorization after a treatment step is a ... [more ▼]

Wastewater treatment plants generate a byproduct which is found in the form of a colloidal suspension, known under the generic term of sludge. At present time, its valorization after a treatment step is a topical environmental issue. This work focuses on the study of the impact of the conditioning step, i.e., the addition of chemicals such as coagulants and flocculants, on the mechanical dewatering and thermal drying steps. The coagulant used (polyaluminum chloride) is combined with a cationic polymer type (flocculant), ranging from linear to complex structures (branched and cross-linked), two of the four flocculants tested with the coagulant are linear structures only differing by their molecular weight. Specifically, the study highlights the role of polyaluminum chloride (PAX-14) as a co-activating agent of the water release during the flocculation stage, when it is combined with the polymer. To better understand the link between this flocculation stage and mechanical dewatering and drying performances, many conditioning ways have been studied and the flocculated sludge obtained was dewatered under a constant pressure using a normalized filtration-expression cell. The dewatered cake obtained after the filtration stage was then characterized in terms of dry solids content, textural properties, desorption isotherms, and finally submitted to a convective drying post-treatment, after the sample was extruded through a circular diameter of 14 mm and cut at a height of a same length, yielding cylindrical samples with a mass of around 2.5 g. Results show that, dual conditioning by applying PAX-14 as a coagulant is an excellent way to improve the cake dryness after the mechanical dewatering step. The interaction between the liquid suspension with polyaluminum chloride and the flocculant offers more attractive yields compared with the use of single conditioning to flocculate the bio-material. Moreover, the efficiency of the two linear flocculants including the use of PAX-14, were shown to produce rather similar performances, while for the same coagulant coupled with trendy or branched macromolecules produce significant differences in terms of increase in dry solids content of the dewatered cake, differences for which the polymer having the highest degree of cross-linking appears to be more beneficial to remove more water contained in the floc after filtration. Sorption isotherms, curves reflecting the hygroscopicity of the product were carried out on the dewatered samples using the DVS equipment (Dynamic Vapor Sorption). Firstly, these experiments confirmed that, curves obtained for wastewater sludge exhibit a sigmoidal shape characteristic of type II, and secondly, an impact of dual PAX-14/polymer conditioning on hydro-textural properties remains difficult to assess. Based on the statistical parameters, GAB equation appears the best formulation to model the sludge sorption isotherms of the Grosses-battes wastewater treatment plant. By studying the texture evolution of sludge for different levels of cake dryness, this work has compared the sludge mechanical properties from the four conditioning types. Globally, results show a more pronounced firmness of the dewatered cake when using the couple PAX-14/polymer in the flocculation stage compared to the single conditioning one. However, from the determined sludge texture parameters it seems difficult to argue that the contribution of both coagulant and cross-linked polymers is better than the association involving aluminum polymerized salt and linear flocculants. Finally, it can be noted that the effects of under or overdosing of chemical can lead to the destruction of material and then, a decrease of sludge cohesion drying rate can be observed. In order to access at the effect of the dual PAX-14/polymer conditioners on drying behavior of sludge samples, some characteristics associated with drying kinetics were compared. According to the statistical analysis, the most significant results were obtained by the association involving PAX-14 and the use of cross-linked flocculants, for which, the polymer which has the highest degree of cross-linking provides a better propensity to remove water contained into flocs after filtration. Linear polymers were shown to produce the same performance. During drying, the texture of the material evolves, including shrinkage and voids development. By X-ray microtomography, this phenomenon has been characterized. The curves of shrinkage volume exhibited a linear decrease with two straight line periods, which the transition seems to be correlated to the sludge water behavior. On the first period, the shrinkage volume can be correlated to the quantity of evaporated water. The texture of the solid material does not hamper the shrinkage process. However, during the second period, the structure of solid stiffens and then influences the shrinkage phenomenon: water is replaced by air and porosity is created. This period corresponds to a phase of decreasing deformation rate (ε) marking the gradual rigidifying of the matrix until no further deformation was observed, the solid was totally rigidified. After drying, the final volume reduction was found to be close to 70% of the initial sample volume for linear and cross-linked flocculants combined with PAX-14, while it was around 75% of the sample initial volume in the case of branched flocculant co-conditioning with the sample coagulant. According to this result, shrinkage depends on both the nature of the sludge and the polyelectrolyte types or dosage. An impact was also found of chemical conditioners on the evolution of porosity. For sludge flocculated by single conditioning, it appears that the porosity was centered on the solid material while for dual conditioning a porosity structured in slats, was identified. This difference in internal structure of the porosity explains the difference in drying kinetics, including the modification of the exchange surfaces available and the average distance of transfer, allowing acceleration or a slow-down of the water removal. [less ▲]

Detailed reference viewed: 70 (5 ULg)
Full Text
See detailInsect pathogenic Aspergillus species in mosquito (Diptera: Culicidae) control compared to Metarhizium anisopliae
Bawin, Thomas ULg

Doctoral thesis (2016)

Many mosquito (Diptera: Culicidae) species are vectors responsible for the transmission of infectious diseases of medical and veterinary importance. Risk for infection considerably increased during the ... [more ▼]

Many mosquito (Diptera: Culicidae) species are vectors responsible for the transmission of infectious diseases of medical and veterinary importance. Risk for infection considerably increased during the last decades due to climate changes and increasing global trade. Vector control is essential for public health management. Integrated pest management is now promoted due to harmful side effects of the chemical insecticides classically used for mosquito control and insect resistance development. This PhD thesis takes part in the selection process of insect pathogenic fungi. Three biological models (Aspergillus clavatus Desmazieres, Aspergillus flavus Link, and Metarhizium anisopliae (Metschnikoff) Sorokin) were selected and investigated regarding their spore insecticidal activity, mode of action, and selectivity. Throughout this scheme, the use of agricultural materials and derivatives in fermentation processes was emphasized. Production methods and insecticidal potential of the fungi were first investigated. On the one hand, the two Aspergillus species were compared to M. anisopliae regarding their spore production when cultured on agro-industrial substrates (white rice and wheat bran) and their insecticidal effect on larvae of the southern house mosquito, Culex quinquefasciatus Say. Our results showed that both substrates are suitable to culture the three insect pathogenic fungal species; but wheat bran-based media increased from 3 to 7-fold the spore yields in solid-state compared to white rice-based media. Also, insect pathogenic Aspergillus species were suggested to yield in similar spore levels in such conditions (in a range of 10^9 spores per g of substrate) and be as virulent against mosquito larvae compared to M. anisopliae. On the other hand, a bioreactor design intended to support large-scale production on agricultural materials by combining the technological advantages of submerged and solid-state fermentations was implemented using A. clavatus. This system allowed facility in recuperation and purification of spores (confined on a packed solid substrate) that retained virulence against mosquito larvae; but also metabolites (contained in a circulating liquid medium) that showed insecticidal effect. The mechanisms responsible for the insecticidal effects of the spores, and their selectivity were then investigated. On the one hand, the invasion routes of A. clavatus spores on mosquito larvae were investigated by light and electron microscopy. Histological observations suggest that toxins secreted by active germinating spores of A. clavatus in the digestive tract altered the larval tissues, leading to necrosis and causing larval death. Fungal proliferation and sporulation then occurred during a saprophytic phase. Such action mode also probably occurred in the case of the two other species. On the other hand, the insecticidal activity of the fungi was assessed against the pea aphid, Acyrthosiphon pisum Linnaeus. Adult A. pisum aphids were susceptible (increased mortality and decreased reproductive potential) to the three fungal species. As a consequence, these fungi would probably be able to infect a broad spectrum of insect hosts (whatever terrestrial or aquatic) once released in the environment. The implications of the results for mosquito control and application strategies are finally discussed, and perspectives for future works proposed. [less ▲]

Detailed reference viewed: 38 (9 ULg)
Full Text
See detailNovel Methods for the Detection of Functional Brain Activity using 17O MRI
Möllenhoff, Klaus ULg

Doctoral thesis (2016)

Detailed quantitative information about metabolic processes plays a crucial role in the potential cure and for treatment of many diseases such as Alzheimer’s disease or brain tumours. In the last decades ... [more ▼]

Detailed quantitative information about metabolic processes plays a crucial role in the potential cure and for treatment of many diseases such as Alzheimer’s disease or brain tumours. In the last decades, radioactive tracers such as 15O have been used to quantify CMRO2 with PET imaging and this is regarded as the gold standard. However, such methods are complicated and expensive as a consequence of the short half-life (2 min) of 15O and inherently include radiation exposure and invasive measurements such as blood probes to probe cerebral blood flow (CBF). Fick’s principle of arteriovenous oxygen difference [1] connects CMRO2 and CBF via the measure of oxygen extraction fraction (OEF). The main goal of this work is to achieve non-invasive measures of OEF based on magnetic resonance imaging (MRI) to quantify CMRO2 allowing straightforward and comfortable patient handling. MRI enables studies of large cohorts of healthy volunteers due to noninvasive measurements and a lack of radioactivity. This can be achieved first by quantitative relaxation time mapping of the transverse relaxation time (T2) of venous blood only in proton (1H) MRI or by a measurement following inhalation of 17O gas and recording the signal curve of directly detected 17O signal. Unfortunately, the most abundant isotope of oxygen (16O) has a zero spin system, and cannot be detected with NMR experiments. In contrast, 17O, a stable isotope with a half-integer spin (I=5/2), can be detected by MR. Fortuitously, however, in MRI it is only visible in the form of metabolically generated H17 2 O and not as a gas. The low natural abundance of 17O, of only 0.037% (of the oxygen atoms) and the low NMR sensitivity (2.9% that of 1H) gives rise to the need for ultra-high-field MRI to reach a significant SNR per unit time. Natural abundance images of a healthy male volunteer were acquired in vivo after having gained written consent within a clinical trial of a 9.4T MRI system (Siemens AG, Erlangen, Germany) [2, 3]. These natural abundance images, which reflect the 17O bound to protons as H17 2 O and thus, the amount of water, are compared to 1H-based quantitative water content imaging. For further studies, the voxelwise knowledge of the quantitative water content is necessary to quantify CMRO2 based on the 17O signal behaviour. To achieve that, methods which were originally used on 1.5T scanners had to be adapted for the use at higher field strengths to overcome RF field inhomogeneities [4–11]. New correction methods were developed based on a well known correlation between tissue T1 and proton density (PD) to estimate the receive bias field properly. These methods were tested for quantitative water content determination. Averaged results in grey (GM) and white matter (WM) respectively of 10 healthy volunteers are H2OWM=70.3 1.4 %, H2OGM=84.7 1.5 %„ T1WM=918 24 ms and T1GM=1509 14 ms. Further, 1H-based imaging methods called QUIXOTIC [12–14] and TRUST [15] appeared in the literature. These methods are based on changes of the proton transverse relaxation rate T2 with different oxygen saturation levels. Quantitative values of venous blood T2 were acquired using a so-called T2prep module or a multi-echo spin echo readout. While the first method suffers from long acquisition times the latter one from large echo-spacing of the spin echoes and stimulated echo effects. Both disadvantages were overcome using an adiabatic multi-shot multi-echo spin echo sequence, which does not suffer from stimulated echo effects and due to the multi-shot capabilities, the echo-spacing is reduced [16]. Mean values in GM of four healthy volunteers are found to be venous oxygenation Yv=0.61 0.03, T2=54 4 ms, CMRO2=174 13 mol/100g min and CBF=53 3 ml/100g min. [less ▲]

Detailed reference viewed: 34 (4 ULg)
Full Text
See detailETUDE DE LA DYNAMIQUE DE LA DESERTIFICATION DANS LE BASSIN VERSANT DE LA MOULOUYA EN INTEGRANT LES DONNEES ISSUES DE LA TELEDETECTION ET LES DONNEES SOCIO-ECONOMIQUES
Mokhtari, Noureddine ULg

Doctoral thesis (2016)

La recherche sur la désertification et la dégradation de l’environnement est très complexe et vise la mise en relation entre les ressources de l’environnement, leurs limites de durabilité et des usages ... [more ▼]

La recherche sur la désertification et la dégradation de l’environnement est très complexe et vise la mise en relation entre les ressources de l’environnement, leurs limites de durabilité et des usages qui se font de ces ressources par l’homme en tant qu’agent économique qui vise à améliorer son bien-être. Dans le bassin versant de la Moulouya caractérisé par un climat essentiellement aride à semi-aride, une augmentation sensible de la population et une forte hausse de la demande en ressources naturelles, le problème de la désertification se pose en termes d’adaptation des besoins de la population aux contraintes du milieu en vue de maintenir la durabilité des ressources. Dans ce sens, le challenge consiste en un double objectif, premièrement l’évaluation de la désertification à travers l’analyse de l’état de dégradation du milieu et deuxièmement, l’étude des causes de cette dégradation moyennant des enquêtes axées sur les pratiques agricoles et la formulation de propositions d’actions à entreprendre pouvant être utilisés de manière opérationnelle par les acteurs locaux et les pouvoirs publics. Ainsi, le suivi de la dynamique des phénomènes biophysiques liés à la désertification s’est fait essentiellement à travers l’étude de l’évolution du climat et de la qualité de la végétation à l’échelle de l’ensemble de la zone étudiée (NDVI) et au niveau d’une zone d’intérêt pour la recherche (occupation du sol). Pour la végétation, le suivi spatio-temporel de la végétation a montré pour les trois sources de données à basse résolution utilisées (GIMMS, MEDOKADS et SPOT) des évolutions similaires de l’indice de végétation NDVI. Malgré les différences entre les amplitudes de variation du NDVI, liées essentiellement aux spécificités des algorithmes de traitement, les trois séries données conservent la même tendance stationnaire au cours du temps. D’une manière générale, les fluctuations du NDVI mises en évidence à l’aide des données NDVI à basse résolution reflètent principalement les variations spatio-temporelles en quantité et en qualité des précipitations d’une année par rapport à une autre et ne montrent aucune tendance particulière concernant la qualité de la végétation. L’identification des zones sensibles à la désertification, réalisée sur la base de l’approche MEDALUS, a montré que les zones fragiles et critiques totalisent 61% de la superficie du bassin versant, soit une superficie d’environ 3,25 millions d’Ha. Spatialement, les zones sensibles à la dégradation se trouvent aussi bien dans la Basse Moulouya que dans les Hauts Plateaux et la vallée de Missour constitués essentiellement de parcours steppiques. L’analyse de la dynamique d’occupation du sol à travers l’utilisation des images satellites (LANDSAT) pour la commune de Tissaf, choisie comme zone d’intérêt pour la recherche, a révélé une dégradation qualitative de la végétation. En effet, de grandes superficies d’Alfa dense à très dense (végétation climacique) se sont dégradées pour se retrouver dans la classe d’Alfa faiblement dense, soit une diminution de l’ordre de 16.199 Ha sur 20 ans. L’analyse des causes de la dégradation des parcours au niveau de la commune de Tissaf à travers l’étude de la productivité des parcours et du système d’élevage pastoral a révélé que le capital, en tant que facteur de production, joue un rôle important dans les stratégies d’utilisation des ressources fourragères « gratuites » issues des parcours collectifs. Ainsi, les grands éleveurs sédentaires ou semi-nomades disposant d’importants fonds propres et grâce à une utilisation plus opportuniste des parcours collectifs paraissent profiter davantage de ces ressources (46.478,15 UF) par rapport aux petits éleveurs sédentaires et transhumants (5.148,70 UF et 18.714,40 UF). Les petits éleveurs qui adaptent l’effectif de leur cheptel en fonction des conditions du milieu (décapitalisation en période de sécheresse) semblent profiter moins en quantité et en qualité des ressources pastorales disponibles. En guise de conclusion, la thèse propose des scénarios d’adaptation des systèmes de production agricoles qui peuvent être utilisés d’une manière opérationnelle par les acteurs locaux et les pouvoirs publics en vue d’orienter les stratégies de développement et d’investissement vers les secteurs rentables économiquement et qui respectent en même temps l’environnement. [less ▲]

Detailed reference viewed: 76 (12 ULg)
See detailLes itinéraires cliniques en support aux mesures transversales d’organisation des soins au patient : expérience de gestion de projet bottom-up
ERPICUM, Marie ULg

Doctoral thesis (2016)

Our work contributes to the study of the health care organization’s evolution, by an integrating approach of clinical, research and teaching fields, in a bottom-up project management which aims ... [more ▼]

Our work contributes to the study of the health care organization’s evolution, by an integrating approach of clinical, research and teaching fields, in a bottom-up project management which aims integration of multidisciplinary and transversal care processes. From a research project was born a service project for the development of a blood management program in cardiac surgery. This project led to the development of a clinical pathway in cardiac surgery. The methodology of clinical pathways has been integrated in the new institutional strategic plan; the concept of “Care pathways” is developed to reinforce the implementation of "patient's pathway" and "Integrated Care" measures. This concept also finds an echo in the legislative and accreditation standards. Our researches and projects highlight the value of nurses for the integration of research and clinical care process. This approach is taught to Public Health Science Master’s students through educational missions in the Advanced Practice Nursing Science. [less ▲]

Detailed reference viewed: 25 (2 ULg)
Full Text
See detailInterferences between non-proliferation and science: ‘exporting’ dual-use know-how and technology in conformity with security imperatives
Charatsis, Christos ULg

Doctoral thesis (2016)

Chapter 1 introduces the reasoning underpinning the study: what are the main drivers and the overall objective for undertaking this intellectual endeavour. It also sets the main questions to be answered ... [more ▼]

Chapter 1 introduces the reasoning underpinning the study: what are the main drivers and the overall objective for undertaking this intellectual endeavour. It also sets the main questions to be answered and a hypothesis to be verified. Chapter 2 sets the scene where the study evolves. What is the role of research and what is the mission of different types of research organisations in today’s environment? The chapter discusses also the definitions of related terms such as Research and Development as these are entrenched in texts with universal applicability. Chapter 3 illuminates the role of knowledge from a proliferation point of view. What are the obligations stemming from legally binding treaties for industry and academia? The chapter also offers a comparative analysis of the multilateral export control regimes including main principles, control lists and terminology used. The concluding section attempts to explain the dual-use problem by providing a definition of dual-use research. Chapter 4 explains the main policies applying for EU funded research by focusing on the dissemination and use of research results for practical and commercial purposes. The chapter offers an analysis of the EU legal framework governing technology transfers of dual-use items. Following that, the main scenarios where trade controls come into play in a research context are discussed. Finally, the chapter offers an analysis of a case study exemplifying the interpretation and implementation of provisions and terms discussed all over the study. The H5N1 case study brings to the fore the differences between the EU and US in the oversight of dual-use research. Chapter 5 presents an assessment of the US trade controls towards academia. How do the US authorities interpret the fundamental research exemption? What is a ‘deemed export’ and how does it affect academic research? How the term ‘publicly available information’ should be understood? Chapter 6 sheds light on the role of internal controls in complying with the law and their nature as discretionary measures. The chapter provides a summary of the main principles and key elements of an Internal Compliance Programme (ICP). Then, it highlights the main steps required for designing and implementing ICPs. Chapter 7 examines the export compliance practices followed by firms, universities and public research organisations. In doing so, it identifies challenges encountered and compliance mechanisms used in different research environments. Chapter 8 sets forward a method for identifying export controls risks in the initial phase of development of an internal compliance structure. The risk identification method builds on international standards and previous experience for tackling export control concerns in a research setting. To that effect, an international public research organisation, the European Commission Joint Research Centre is used as a test case. Finally, chapter 9 compiles the main findings of the study responding also to the main questions set forth in the introductory chapter. [less ▲]

Detailed reference viewed: 42 (3 ULg)
Full Text
See detailAn efficient and flexible software tool for genome-wide association interaction studies
Van Lishout, François ULg

Doctoral thesis (2016)

Humans are made up of approximately 3.2 billion base pairs, out of which about 62 million can vary from one individual to another. These particular base pairs are called single nucleotide polymorphisms ... [more ▼]

Humans are made up of approximately 3.2 billion base pairs, out of which about 62 million can vary from one individual to another. These particular base pairs are called single nucleotide polymorphisms (SNPs). It is well known that some particular combination of SNP values increase dramatically the risk of contracting certain type of disease, like Crohn's disease, Alzheimer, diabetes and cancer, just to name a few. However, there are still a lot of new discoveries to make and specialized software is required for this task. It has been shown that individual SNPs cannot account for much of the heritability on their own. Therefore, this PhD thesis is dedicated to interaction studies, the purpose of which is to identify pairs of SNPs and/or environmental factors that might regulate the susceptibility to the disease under investigation. Model-Based Multifactor Dimensionality Reduction (MB-MDR) is a powerful and flexible methodology to perform interaction analysis, while minimizing the amount of false discoveries. Before this thesis, the only available implementation was an R-package taking days to analyze a dataset composed of just hundred of SNPs. However, a typical dataset contains hundreds of thousands or millions of SNPs, even after data cleaning and quality control. The aim of this thesis is to write a software able to analyze such datasets within a few days with the MB-MDR methodology. In other words, the goal is to get 10^8 times faster than the R-package, while still remaining powerful, flexible and keeping the amount of false discoveries low. Several contributions were needed to reach this goal and are presented in this thesis. First, a new software was written from scratch in C++, in order to be able to optimize every single computation, instead of relying on too generic functions as was the case for the R-package. Second, the methodology itself was improved, irrespective of the programming language. Indeed, MB-MDR is based on the maxT algorithm (introduced by Westfall&Young in 1993) to assess significance of the results and it can be customized for interaction analysis. A first major contribution of this PhD work, called Van Lishout's implementation of maxT, was introduced in 2011. The parallel version of this algorithm enables to analyze a dataset composed of hundred thousands of SNPs within a few days. The most important contribution of this thesis, called the gammaMAXT algorithm, was introduced in 2014. The parallel version enables to analyze a dataset composed of one million SNPs within one day. In this thesis, we also propose a new viewpoint to handle population stratification and correct for covariates. Many simulated and real-life data analysis are provided, to highlight the flexibility of the software and its ability to find interesting results from a biological point of view. The latest version, called mbmdr-4.4.1.out, can be downloaded freely at http://www.statgen.ulg.ac.be with the corresponding documentation. [less ▲]

Detailed reference viewed: 50 (15 ULg)
Full Text
See detailLa question urbaine revisitée. Analyse socio-politique comparée de la régulation publique des inégalités environnementales
Lejeune, Zoé ULg

Doctoral thesis (2016)

Les inégalités environnementales forment un relatif « impensé » de la plupart des politiques publiques qui sont aujourd’hui mises en place dans nos villes. S’il apparaît qu’il y a une sous-estimation de ... [more ▼]

Les inégalités environnementales forment un relatif « impensé » de la plupart des politiques publiques qui sont aujourd’hui mises en place dans nos villes. S’il apparaît qu’il y a une sous-estimation de cet enjeu de la part des autorités politiques au sens large, il nous a semblé utile de mieux comprendre les processus socio-politiques à l’œuvre. C’est un double mouvement que nous interrogeons dans la thèse. D’une part, quels sont les processus « sociétaux », collectifs qui contribuent à la production de phénomènes inégalitaires en matière environnementale ? D’autre part, quels sont les dispositifs socio-politiques qui se dessinent afin d’y trouver une solution collective et politique ? La première approche privilégiée pose la question des conditions sociétales de la formation et de l’émergence des inégalités environnementales : distribution des charges environnementales, inégale participation dans la vie publique et collective et inégalités socio-spatiales. Cette première question nous a conduit à mobiliser les données du Baromètre social de la Wallonie 2012 et son module de questions sur l’environnement. La seconde grande question interroge les modalités de la gestion collective et publique des inégalités environnementales, à savoir les solutions mises en place aujourd’hui pour y faire face. Cette analyse se propose dès lors d’étudier les modalités de la régulation publique des inégalités environnementales dans une perspective comparative internationale face à la transformation de l’action collective et publique urbaine. Pour ce faire, nous avons réalisé des enquêtes de terrain qualitatives (entretiens semi-dirigés) dans plusieurs villes, en Angleterre (Sheffield) et en Belgique (Liège). Celles-ci nous ont conduit à proposer un modèle conceptuel de lecture de la régulation publique des inégalités environnementales en milieu urbain. [less ▲]

Detailed reference viewed: 34 (10 ULg)
Full Text
See detailRhodococcus erythropolis T902.1 as a bioaugmentation starter: mechanisms, constrains and potentialities for the hydrocarbon degradation
Masy, Thibaut ULg

Doctoral thesis (2016)

Since the advent of the industrial revolution in the 19th century, anthropogenic activities and lack of environmental concern gave birth to numerous contaminated areas. Amongst released pollutants ... [more ▼]

Since the advent of the industrial revolution in the 19th century, anthropogenic activities and lack of environmental concern gave birth to numerous contaminated areas. Amongst released pollutants, hydrocarbons (HC) are the most widespread in the environment but they can also constitute a carbon source for numerous microorganisms. Therefore, bioremediation (i.e. the use of microorganisms to degrade pollutants) appears as an ecologically- and cost-effective technique compared to chemical or physical treatments. This biotreatment technology often relies either on stimulating indigenous microorganisms already present in soil (biostimulation) or on adding specific microbial degraders (bioaugmentation) to enhance the natural attenuation of contaminants. However, there is a need for improved understanding of the causes that can lead to its failure or its low efficiency, such as diverse environmental constraints or poor adaptation ability of laboratory-cultivated microorganisms. Amongst bacteria studied, Rhodococcus sp. has been previously described as a potential candidate for bioaugmentation due to its ability to degrade a broad range of organic pollutants, to produce biosurfactants, which improves pollutant bioavailability, and to rapidly adapt to many environmental stresses (e.g. desiccation, low temperature, high salinity). The main objective of this work is thus to assess the potentiality and limitations in the use of a specific strain, Rhodococcus erythropolis T902.1, to degrade HC (from simple n-alkanes to polyaromatic) in diverse field conditions. The factors limiting such a process have to be identified and, as much as possible, overcome. A first bioaugmentation experiment in microcosms aimed at identifying these constrains in carbon and clay-rich soils contaminated with heating oil. This treatment was successful in strongly polluted soil, since the addition of the strain T902.1 helped in redirecting the limited quantity of available oxygen towards a higher HC degradation and also correlated with a higher proportion of degrading genes in bioaugmented soils, compared to biostimulated and control ones. However, this effect decreased with time as T902.1 development was curtailed by competition and potentially predation from the endogenous flora. In addition, HC were heterogeneously distributed and this hampered the detection of a real degradation in lowest polluted soils. As a result, inoculation should be targeted to highly polluted areas (e.g. contaminant source zones), but it requires controlling soil heterogeneity.   We thus resorted to electrical resistivity tomography (ERT), to describe this heterogeneity and to monitor bacterial HC degradation activity. This geophysical tool could discriminate lithological heterogeneities that were artificially introduced in a 2 m³ pilot. Compared to a first insufficient biostimulation phase, the introduction of R. erythropolis T902.1 in this pilot led to a HC depletion of almost 80% (6900 to 1600 ppm) in 3 months in the injection zone, where pollutants were less bioavailable. Simultaneously, HC mineralization and biosurfactant production were deduced from the monitoring of ERT, biological and physicochemical parameters. In another study, R. erythropolis T902.1 could form stable biofilms on the materials constituting draining pavement structures, which allowed its long-term survival in a real parking lot and improved the decontamination of runoff water drained through this structure during pollution tests carried out at a pilot scale. This indicates that the strain could be widely used in other decontaminating systems and not only in soil. Furthermore, this biofilm formation could be triggered by an appropriate pre-adaptation of the cells before their injection in the polluted environment, to ensure a higher ecological robustness of the inoculum, compared to the one observed in the microcosm experiment. A third constrain is the poor or slow degrading activity toward some recalcitrant compounds, such as polyaromatic HC (PAH). Metallic nanoparticles synthesized by a sol-gel process were considered as potential catalysts for the improvement of degradation kinetics. Iron nanoparticles boosted the bacterial catalytic activity of the strain T902.1 in liquid cultures containing biphenyl as the sole carbon source. Following results suggested that the iron encapsulated in the porous silica matrix, was progressively attracted by siderophores (heterobactins) produced by the strain. However, this hypothesis has still to be confirmed by further analyses. From these experiments, R. erythropolis T902.1 globally proved to compete and improve degradation rates in highly polluted soils compared to biostimulation, even under low oxygen and nutrient contents. Notably, the production of trehalolipidic biosurfactants enhances HC bioavailability for their further uptake by the strain and surrounding microorganisms. Furthermore, this strain forms stable biofilms on several supports, which increases its lifespan and paves the way for many applications in bioremediation systems. Finally, it can also be used in synergy with sol-gel iron nanoparticles to treat recalcitrant compounds such as PAH and some chlorinated aromatics, but this combination needs to be further tested in more complex media, such as soil or waste water. [less ▲]

Detailed reference viewed: 57 (8 ULg)
Full Text
See detailThree Essays on Market Liquidity in Equity Markets
Bazgour, Tarik ULg

Doctoral thesis (2016)

Over the past decades, market liquidity has been a major issue for stock market participants and even becomes one of the most important challenges since the recent financial crisis. In this context, this ... [more ▼]

Over the past decades, market liquidity has been a major issue for stock market participants and even becomes one of the most important challenges since the recent financial crisis. In this context, this dissertation is centered on this topic and presents three empirical essays incorporating liquidity considerations in three different subfields of Finance, namely, asset pricing, portfolio allocation and mutual fund timing. The first essay (Chapter 2) is related to asset pricing and demonstrates that liquidity and quality are priced characteristics in the stock market, but their pricing is conditional on market volatility conditions. The second essay (Chapter 3) is devoted to portfolio allocation and shows that aggregate market liquidity shocks has a significant influence on optimal portfolio allocations. In addition, it emphasizes that liquidity-responsive strategies could be a valuable tool for investors and portfolio managers to actively manage risks and capture return opportunities. The third essay (Chapter 4) focuses rather on mutual fund timing and examines what style liquidity timing skills may mutual fund managers possess. This study highlights that, in anticipation of aggregate market liquidity changes, mutual funds do not switch their investments between stocks and cash but they rather switch between only small and large stocks. Overall, the main message to take away from this research is that investors and portfolio managers should take into consideration both the liquidity of their individual stocks and the liquidity of the market as a whole. [less ▲]

Detailed reference viewed: 37 (4 ULg)
Full Text
See detail“The Sweet Smell of Chemistry” - Characterization of volatile mixtures from Life Sciences
Stefanuto, Pierre-Hugues ULg

Doctoral thesis (2016)

From a Separation Science standpoint, Life Sciences represent a broad source of complex compound mixtures that require powerful analytical strategies to be considered when characterization is aimed. The ... [more ▼]

From a Separation Science standpoint, Life Sciences represent a broad source of complex compound mixtures that require powerful analytical strategies to be considered when characterization is aimed. The depiction of the complex volatile organic compound (VOC) component of these mixtures is an important part of such characterization. The aim of this doctoral work was to develop a versatile analytical approach to resolve such VOC samples. For the characterization of complex VOC mixtures, comprehensive two-dimensional gas chromatography (GC×GC) is the method of choice. The combination of two GC separation columns offers higher peak capacity than single dimension GC (1D GC). Moreover, the hyphenation of GC×GC to a mass spectrometer provides an extra dimension of identification, especially when high-resolution (HR) time-of-flight mass spectrometers (TOFMS) is used. However, the optimization of the GC×GC conditions is not straightforward. Currently, there are no defined strategies to obtain the best capabilities these instruments, not only in terms of the optimization of the separation itself, but also mainly in terms of data processing efficiency. The first section of this work was devoted to the evaluation of theoretical aspects and the definition of a specific optimization strategy for GC×GC separation. The first part dealt with the heavily debated concept of ‘orthogonality’ was specifically investigated by means of a metric calculation, the Orthogonality Index (OI), linked to a new nomenclature describing the separation space usage. The second part was focused on the development of an optimization strategy for the sampling and the chromatographic separation of VOCs, as well as the processing of large sets of GC×GC data. This was conducted on complex beer aroma headspace replicates for sampling method selection, peak dispersion optimization, and robust multivariate statistical treatment. The third part of this theoretical investigation relied on the implementation of fast-GC conditions for GC×GC separation. The idea was to evaluate the effect of combining short columns, fast modulation, high temperature ramping, and high flow on GC×GC efficiency for explosive headspace analyses. In the second section, the focus was directed to challenging applications in the area of thanatochemistry, i.e. the chemistry of death, especially considering the volatile fraction of cadaveric decomposition, a complex chemical process releasing numerous VOCs. In this context, soil surrounding decomposing remains, headspace of cadavers, and more “specific” matrices (i.e. synthetic solutions and internal gas from decomposition) were analyzed by GC×GC TOFMS. Major attention was dedicated to the development of an analytical and data mining procedures for these complex VOC samples with emphasis on the study of the impact of different parameters on the cadaveric decomposition process. [less ▲]

Detailed reference viewed: 33 (8 ULg)
Full Text
See detailDe l'activation des politiques d'emploi à l'agitation des chômeurs
Beuker, Laura ULg

Doctoral thesis (2016)

• Ce travail de thèse a pour objet la traduction et la mise en œuvre concrète du Plan d’accompagnement et de suivi des demandeurs d’emploi par les conseillers emploi (FOREm et Actiris) et par les ... [more ▼]

• Ce travail de thèse a pour objet la traduction et la mise en œuvre concrète du Plan d’accompagnement et de suivi des demandeurs d’emploi par les conseillers emploi (FOREm et Actiris) et par les facilitateurs (ONEm) en Belgique francophone. Ceux-ci sont effectivement situés en première ligne dans la mise en « actes » et en « mots » de cette mesure d’activation. Notre entrée dans les pratiques d’accompagnement et de suivi des demandeurs d’emploi repose sur une démarche empirique foncièrement qualitative. Le travail de terrain s’est déroulé entre janvier 2013 et février 2014. Il repose sur une immersion au sein de huit sites, et articule la réalisation d’entretiens semi-directifs, la récolte de documents internes et l’observation d’entretiens. Prenant appui sur les apports de l’Economie des conventions, de la Nouvelle sociologie économique et de la Sociologie des groupes professionnels, ce travail met en exergue l’idée selon laquelle plutôt que « d’activer » les demandeurs d’emploi, il est question « d’agiter » ces derniers… [less ▲]

Detailed reference viewed: 26 (4 ULg)
Full Text
See detailNumerical Modeling and Experimental Identification of Mistuned Multi-Stage Bladed Assemblies
Nyssen, Florence ULg

Doctoral thesis (2016)

In turbomachinery, low pressure compressors are composed of a succession of bladed disks. To reduce the mass and increase the performance of the aircraft engines, one-piece multi-stage units of bladed ... [more ▼]

In turbomachinery, low pressure compressors are composed of a succession of bladed disks. To reduce the mass and increase the performance of the aircraft engines, one-piece multi-stage units of bladed disks have been recently developed. But these one-piece technologies are challenging for the mechanical design due to exacerbated effects of mistuning (i.e., mode localization and forced response amplification). In the thesis, an experimental method for the identification of mistuning in multi-stage bladed structures is proposed and validated. Numerical modeling methods are proposed to reduce computational times for the statistical predictions of the forced response amplification. A characterization of the interstage coupling is performed and a criterion is proposed to predict in advance if a multi-stage analysis is necessary. [less ▲]

Detailed reference viewed: 42 (9 ULg)
Full Text
See detailStudy of the ORF63 gene of Murid herpesvirus 4
Latif, Muhammad Bilal ULg

Doctoral thesis (2016)

Detailed reference viewed: 11 (2 ULg)
Full Text
See detailCharacterization, dynamics and trophic ecology of macrofauna associated to seagrass macrophytodetritus accumulations (Calvi Bay, Mediterranean Sea)
Remy, François ULg

Doctoral thesis (2016)

Posidonia oceanica meadows are a major coastal Mediterranean ecosystem. Although highly productive this Mediterranean marine flower plant is not much consumed by herbivore organisms. During autumnal ... [more ▼]

Posidonia oceanica meadows are a major coastal Mediterranean ecosystem. Although highly productive this Mediterranean marine flower plant is not much consumed by herbivore organisms. During autumnal senescence, most (up to 90%) of the foliar primary production of P. oceanica ends in the “detrital compartment”. These dead leaves, also called “macrophytodetritus”, begin to degrade immediately inside the meadow, but a large amount will be rapidly exported to adjacent unvegetated accumulation zones, such as bare sand patches. Associated to drift macroalgae, living detached P. oceanica shoots, micro-organisms and fine sediment, these macrophytoderitus form what we call “exported P. oceanica litter”. This exported litter is a highly dynamic habitat for a whole community of invertebrates: meiofauna (38µm < size < 500µm) and macrofauna (size ≥ 500µm) on which we focused on. This dynamic nature of exported litter could play a major structuring role in terms of abundance, diversity and trophic ecology of this vagile macrofauna community at a seasonal, annual or spatial scale, but also during stochastic, brief and very strong perturbations: resource pulses. In this context, this PhD Thesis had 7 main objectives: i. Characterize for the first time exhaustively the macrofauna community. ii. Evaluate the spatiotemporal changes occurring at two different time scales in the detritus themselves and in the macrofauna community. iii. Relating these variations with measured environmental parameters. iv. Experimentally demonstrate the stratification occurring in a stable P. oceanica litter accumulation and the impact of this stratification on environmental conditions and on the macrofauna. v. Experimentally demonstrate the impact of resource pulses on the exported P. oceanica litter macrofauna community. vi. Unravel for the first time the global P. oceanica litter macrofauna food web using gut contents examinations and stable isotopes (C and N). vii. Evaluate the spatiotemporal changes of diet preferences of this community and determine if the observed changes are really synonym of true diet changes. This PhD Thesis demonstrated that exported P. oceanica litter was mainly composed of dead P. oceanica leaves (70-80%). It followed the natural annual cycle of P. oceanica and presented a maximum abundance in autumn just after leaves senescence. Measured environmental parameters also showed important variations linked to different factors such as force and direction of the wind, litter abundance and probably temperature. The continuous presence of the vagile macrofauna community throughout the year was demonstrated as well. This community was composed of 115 species and largely dominated by arthropods (77%), followed by annelids (12%) and mollusks (7%), while other taxa were much more anecdotal. Even if diversity is quite important, only a few species dominate largely the community. Indeed, 19 species represent more than 90% of the total abundance. One species to keep in mind: Gammarella fucicola, the most typical dominant and abundant amphipod species, representing 40-50% of the total abundance. In addition to this general pattern, litter vagile macrofauna presented important seasonal and annual variations. In the case of several species, these variations could be linked to some measured environmental parameters, but we had to recognize that most species did not seem to be influenced by environmental parameters measured during this PhD. However, oxygen concentration was the most important environmental parameter, potentially influencing 7 of the 19 most dominant and abundant species. The experimentally demonstrated physico-chemical stratification occurring inside litter accumulations was strongly related to this oxygen parameter. Indeed we demonstrated that several species were distributed in the different layers of a litter accumulation according to oxygen concentration and to a lesser extent, to nutrients concentration (mostly NH4). Besides, smaller time scale sampling allowed the identification of several stormy events corresponding to the definition of resource pulses. These pulses were demonstrated to play a potentially important role on the structure of the macrofauna community, favoring importantly the detritivore species and hypoxia tolerant species. It was also demonstrated that resource pulses could induce diet switching increasing the consumption of dead P. oceanica leaves just after the events, potentially increasing the litter decomposition by the macrofauna. The trophic web described in this PhD Thesis was composed of several trophic levels, from the primary herbivore/detritivore consumer, to second order carnivore predators. Different dietary preferences were highlighted, but major information was that dead P. oceanica leaves were ingested by a majority (85%) of the sampled species. Moreover, stable isotope analysis confirmed that P. oceanica litter was assimilated by most primary consumers and this “detrital signal” could be identified to the upper trophic levels, which is an argument in favor of the importance of macrofauna as major dead P. oceanica leaves decomposers. This also highlighted their potential role in terms of organic matter transfer from the P. oceanica meadow itself to the Mediterranean coastal food webs. Seasonal variations were observed in terms of trophic niches, and SIAR mixing model confirmed that this variability was sometimes caused by real diet modifications, potentially linked to the variable availability of food sources. This PhD Thesis, combining standardized sampling at two different time scales, trophic web analysis (gut contents and stable isotopes) and original experimentation allowed us to describe a diverse and abundant macrofauna community associated to P. oceanica exported litter, its temporal variations, potential responses to resource pulses as well as the link existing between some species and measured environmental parameters. This PhD also described the food web of this community and demonstrated the importance of dead P. oceanica leaves as food source for many invertebrates composing this community. These invertebrates thus seemed to play an important role in both litter decomposition and organic matter flux from the P. oceanica meadow to the Mediterranean coastal food webs. [less ▲]

Detailed reference viewed: 86 (20 ULg)
Full Text
See detailSolid-supported synthesis of peptidoglycan fragments and their biological evaluation
Simon, Justine ULg

Doctoral thesis (2016)

In this work, a new methodology for the synthesis of peptidoglycan fragments containing (2S,6R)-A2pm is proposed. Thanks to a solid phase platform, cross metathesis was achieved between two easily ... [more ▼]

In this work, a new methodology for the synthesis of peptidoglycan fragments containing (2S,6R)-A2pm is proposed. Thanks to a solid phase platform, cross metathesis was achieved between two easily manufactured chiral synthons, allylglycine anchored to a resin and vinylglycine derivatives. Due to the need of fragments for the study of the peptidoglycan recycling, this modular efficient platform could be useful to synthesize diverse derivatives of other peptides and muropeptides containing (2S,6R)-A2pm. In the framework of this project, (S)-Ala-γ-(R)-Glu-(2S,6R)-A2pm-(R)-Ala and γ-(R)-Glu-(2S,6R)-A2pm were synthesized. Their interactions with the R39 peptidase were studied by X-ray diffraction. According to the crystallographic results, (S)-Ala-γ-(R)-Glu-(2S,6R)-A2pm-(R)-Ala 1 is a reversible covalent binding inhibitor of R39. These data are supported by an enzymatic study using the thioesterase activity of the R39 peptidase on (R)-S2d. Because of the specific affinity for the R enantiomer of thioesters, the enantioselective synthesis of (R)-S2d is described that makes use of the coupling agent T3P. A chromatographic method is proposed to evaluate the degree of thioester racemization. The kinetics of the interaction between the thioester and different PBPs were studied and a protocol for microtiter plate-based assays is developed allowing the screening of compound libraries for inhibitors of PBPs. In the future, the synthesized peptidoglycan fragments will be used as reference compounds in the framework of the NetRBI project. [less ▲]

Detailed reference viewed: 51 (11 ULg)
Full Text
See detailLe passé en France au XVIIe siècle. Représentations, usages et transferts des savoirs historiques
Saal, Caroline ULg

Doctoral thesis (2016)

La majeure partie des études sur le passé au XVIIe siècle se porte sur l’historiographie, sur la théorie de l’histoire et sur son écriture à cette époque. Grâce au développement de l’histoire des idées et ... [more ▼]

La majeure partie des études sur le passé au XVIIe siècle se porte sur l’historiographie, sur la théorie de l’histoire et sur son écriture à cette époque. Grâce au développement de l’histoire des idées et de l’histoire culturelle, de nouvelles approches ont émergé. Pour l’histoire moderne française, elles prennent essentiellement la forme d’études de figures souvenirs et de leur prégnance dans une culture donnée. Mais deux postulats m’ont invitée à travailler autrement, hors des pratiques historiennes et sans choisir a priori de figures-souvenirs. Le premier tient à l’acquisition des savoirs historiques. La connaissance que possède une personne sur le passé de la communauté humaine résulte d’une multitude de vecteurs et de médias, de nature et d’objectifs divers, et, plus encore, elle résulte de leur croisement. Le second postulat provient des innovations en histoire des savoirs de ces dernières années : une société ancienne repose sur un système de pensée et sur une configuration des savoirs distincte de la nôtre. Pour travailler sur les savoirs sous l’Ancien Régime, il faut appréhender l’altérité d’un ancien régime des savoirs et, plutôt que de rechercher la généalogie de disciplines, regarder à l’œuvre ces savoirs mixtes, aux nombreuses ramifications, la manière de les créer, de se les approprier et de les utiliser. Certes, Reinhart Koselleck et Kristof Pomian avaient déjà produit d’importants enseignements sur les processus. On a longtemps considéré qu’ils avaient probablement tout dit. Il fallait pourtant vérifier la percolation de ces enseignements au-delà des génies créateurs et des penseurs institués. Cette thèse étudie ces processus dans des opérations d’appropriation des savoirs historiques au sein des publics alphabétisés et la compréhension de ces savoirs en société : les pamphlets « historiés » de la Fronde, les conférences du Bureau d’Adresse de Théophraste Renaudot et des estampes ludiques – jeux de carte et jeux de l’oie historiques. Elle démontre le rôle de ces imprimés de forme brève comme lieux d’acculturation des savoirs historiques, mettant à disposition un prêt-à-penser sur le passé. S’inspirant des grilles de lecture des théories de la pensée complexe, développée entre autres par Edgar Morin, elle éclaire la pluralité des questions que se posaient les hommes de l’époque moderne sur leur passé, et les liens entre ces questions, leur lieu social d’émergence, les pratiques de la connaissance et les paradigmes culturels. [less ▲]

Detailed reference viewed: 64 (13 ULg)
Full Text
See detailLa gestion des ressources humaines au sein des ONG internationales: les relations siège-filiale dans un contexte instable (le cas du Burundi)
Hakizumukama, Alexis ULg

Doctoral thesis (2016)

Executive summary Applied to different contexts, the approach to management and HRM practices initially operative, considered by some as the essential and universal key to organizational success, may face ... [more ▼]

Executive summary Applied to different contexts, the approach to management and HRM practices initially operative, considered by some as the essential and universal key to organizational success, may face some contextual constraints and lead to conflicting results. Now, the local context brings to the subsidiary of international organizations little or no opportunities for the Headquarters. At the same time, the local context adds specific constraints. The consideration of these opportunities and constraints by the officials of the subsidiary is a real managerial challenge for them. This implies much more than a simple transfer of what has always worked well elsewhere. This questioning of the success of the universalist perspective pushes us to diagnose other possible ways to suggest for the approach to management and HRM practices that could better accommodate the local management. Our study is particularly concerned with international NGOs operating in sub-Saharan Africa and Burundi in particular. Our theoretical argument mobilizes universalist, culturalist and institutionalist approaches. Our study concerns only the subsidiaries of international NGOs and not their Headquarters. Note that throughout our work, the word "Siège" means the Headquarters and not the local management of the subsidiary. To mark this distinction, we opt to write it with a capital "S". Based on a contextualist analysis of five case studies of subsidiaries of international NGOs, we find that, upon their arrival or within the first years of implementation of the subsidiary, the leaders of these international subsidiaries almost always opt for a relational or even paternalistic model of management. Indeed, this model allows a gain in confidence and the establishement of strong relationships between the expats and the locals, and between volunteers and employees. The latter model also helps to react or deal with the complexity of an unstable local context (civil war, hatred and ethnic conflicts, distrust versus foreigners, oral tradition culture, lack of separation between work and family life, lack of some skills in the labor market and poverty of the population). Beyond the local constraints, pressure from the Headquarters, and the donors' requirements often result in the evolution of the business model implemented during the establishment period. But toward what model is moving the subsidiary, why, how and what are the implications for HRM practices? This is the series of questions we try to answer throughout this work. To get there, we pay special attention to the power games, the identification of the most influential players, the relationships, the mechanisms of prevention and / or of conflict management and the mobilization around the common goal. Our study shows that the managers of subsidiaries have two possible choices of a position: control logic or adaptation logic. The results of our research argue for the second option to be the most favorable to take into consideration the local context and to contribute to the emergence of consistent and very innovative HRM practices. Our work shows that the model based on the adaptation logic is more effective when the appropriation of the Headquarters rule by the members of the subsidiary is dominated by joint regulation mechanisms, and when the management of the subsidiary is polyphonic for what concerns managing the evolution of contextual factors. In fact, the latter mechanisms lead to the organization, in due time, to a genuine process of organizational change. The polyphonic style is generally characterized by flexibility, autonomy, accountability, collaboration, cooperation within teams and the search for compromise to satisfy the essential interests of the different stakeholders, including those at Headquarters. However, we note that some managers, guided by rational mimicry derived from the culture of their country of origin and their experience elsewhere, tried control-based management resulting in the domination of regulatory mechanisms either autonomous or controlled. Our observation is that the control-based management model leads the subsidiary in a logic of submission or circumvention of the rules and practices developed by the parent company. This management model quickly faces major resistance from certain groups of stakeholders who feel that their interests are threatened. For example, internal conflicts occur in these subsidiaries at the expense of the cooperation and the achievement of desired results. Highlighting the importance of the local context and the relationships Headquarters- subsidiaries together with the role of the management style in the evolution of HRM practices in the local management of international NGOs working in unstable and specific context (land and sector insufficiently studied up to now), this study brings a great contribution to international management and intercultural management theory in general and sub-Saharan Africa in particular. [less ▲]

Detailed reference viewed: 62 (13 ULg)
Full Text
See detailImproving probiotic viability and functionality by bioreactors engineering
Nguyen, Huu Thanh ULg

Doctoral thesis (2016)

There is a growing market for probiotic bacteria, but their production is still the subject to technical limitations, i.e. susceptibility to the stress conditions found during upstream and downstream ... [more ▼]

There is a growing market for probiotic bacteria, but their production is still the subject to technical limitations, i.e. susceptibility to the stress conditions found during upstream and downstream operations. In this work, we have investigated the effect of cultivation and drying conditions on Bifidobacterium bifidum MG 25628, a probiotic bacteria being particularly sensitive to bioprocessing conditions. Previous results have shown that microbial physiology, and the ability of microbes to cope with stress, is dependent of the growth rate and the growth phase. It is also known that the preliminary exposure of microbial cells to sub-lethal stress enhance its robustness. Accordingly, the effect of the exposure of B. bifidum in a two-compartment reactor designed in order to expose the strain to different temperature conditions was investigated. We found that the exposure of B. bifidum at 42°C for 1h at the onset of the stationary phase enhanced significantly survival after freeze-drying. It appeared that the increase in cell survival was attributed to the induction of the synthesis and an exopolysaccharide layer surrounding the cells. The method involving the exposure of the strain to sub-lethal temperature stress was further successfully scaled-up to a bioreactor volume of 2000 L. EPS synthesis can also be stimulated by sparing the bioreactor with carbon dioxide. In this context, we investigated the EPS yield in two specific bioreactor designs for the intensification of the CO2 gas-liquid mass transfer, i.e. a trickle bed and a falling-film microreactor. Depending of the operating conditions, these two bioreactor configurations led to a significant improvement in EPS synthesis (around 21 g/L). Extensive comparative proteomic analysis confirmed the impact on CO2 mass transfer on cell physiology, notably by enhancing the intracellular concentration of two key enzymes implied in carbonate uptake, i.e. phosphoenolpyruvate carboxylase and carbamoyl phosphate synthase. Taken altogether, these results point out that biochemical engineering parameters can be used as a very efficient strategy for improving probiotic robustness. Additionally, this non-GMO approach is more suited to the consumer expectations. [less ▲]

Detailed reference viewed: 97 (19 ULg)
Full Text
See detailLa portabilité du statut personnel dans l’espace européen : De l’émergence d’un droit fondamental à l’élaboration d’une méthode de la reconnaissance
Pfeiff, Silvia ULg

Doctoral thesis (2016)

Opposer un refus de reconnaissance au statut personnel d’un individu revient à renier une partie de son identité. Le fait que des citoyens européens puissent subir les inconvénients liés à la survenance ... [more ▼]

Opposer un refus de reconnaissance au statut personnel d’un individu revient à renier une partie de son identité. Le fait que des citoyens européens puissent subir les inconvénients liés à la survenance d’un statut ‘boiteux’ lors de l’exercice de leur liberté de circulation est-il compatible avec les droits et libertés garantis par la Convention européenne des droits de l’homme et les Traités européens ? Cette question était à l’origine de notre recherche doctorale. Celle-ci nous a menés à nous interroger sur l’étendue des droits et libertés européens, tels qu’ils découlent de la jurisprudence de la Cour européenne des droits de l’homme et de la Cour de justice de l’Union européenne, et à explorer les pistes de solutions que recèle aujourd’hui le droit européen en tant que cadre supranational pour l’ensemble des États membres. Sous l’impulsion motrice de la Cour européenne des droits de l’homme et de la Cour de justice de l’Union européenne, la protection de la portabilité du statut personnel a connu ces dernières années des développements sans précédent. Il s’imposait dès lors de dégager les lignes directrices de cette importante œuvre prétorienne. Celles-ci s’imposent, de lege lata, aux États membres dès lors qu’ils envisagent de refuser de reconnaître le statut personnel d’un citoyen européen cristallisé dans un autre État membre. Il peut, à notre sens, être déduit de cette jurisprudence qu’un refus de reconnaissance du statut personnel constitue une ingérence dans le droit à la vie privée et familiale, lorsque la personne concernée nourrissait une confiance légitime en la permanence de son statut. Un tel refus risque également, par ricochet, de priver la personne de certains droits patrimoniaux liés à son statut, tel un droit successoral ou une créance alimentaire. La reconnaissance pourrait alors devenir un préalable nécessaire au respect de ses biens et, par conséquent, son refus constituer une ingérence à ce droit fondamental. Dans certaines circonstances, le refus de reconnaissance peut également porter atteinte au principe d’égalité ainsi qu’au droit à un procès équitable, pour autant que le statut personnel découle d’une décision judiciaire. Enfin, la discontinuité du statut personnel peut constituer une entrave à la liberté de circulation et porter atteinte à la citoyenneté européenne. Dès lors, l’existence d’un droit fondamental du citoyen européen à la permanence de son statut personnel acquis dans un État membre nous paraît s’inscrire dans la droite ligne des principes fixés par les deux Hautes juridictions européennes. Ce droit n’est cependant pas absolu. La jurisprudence tant strasbourgeoise que luxembourgeoise admet – dans des mesures comparables au demeurant – que l’État d’accueil puisse refuser de reconnaître le statut personnel acquis à l’étranger, pour autant que cela s’avère nécessaire à la protection de son intérêt légitime. Ces considérations nous ont amenés à conclure que les motifs abstraits de refus de reconnaissance traditionnellement retenus en droit international privé ne devraient plus permettre de justifier, à eux seuls, un refus de reconnaissance dans le contexte intra-européen. Ainsi, nous pensons que l’État d’accueil ne devrait plus pouvoir refuser de reconnaître un statut cristallisé dans un autre État membre pour le seul motif qu’il n’a pas été établi conformément à la loi désignée par sa règle de conflit, ou que l’État membre d’origine ne pré-sente pas de liens jugés suffisants avec la personne concernée. Si le refus de reconnaissance ne s’appuie pas, en outre, sur la volonté de protéger un intérêt légitime du for, il ne répondrait pas aux critères fixés par la jurisprudence européenne. En effet, le respect d’une règle abstraite de conflit de lois ou d’une exigence de liens suffisants ne paraît pas constituer un objectif légitime suffisant aux yeux des deux Cours européennes. La protection de ces règles abstraites ne semble, au demeurant, pas proportionnée à l’atteinte portée au droit à la permanence du statut personnel. De lege lata, nous estimons que seules l’exception de fraude, entendue très étroitement, et l’exception d’ordre public pourraient justifier, à elles seules, un refus de reconnaissance. Le cadre général ainsi posé, nous nous sommes consacrés dans la seconde partie de notre recherche – que nous avons voulue créative – à tenter de tracer, à la lumière de la jurisprudence européenne, les contours d’une méthode européenne de la reconnaissance. Cette méthode est une variante de ce qu’il est communément admis d’appeler la, ou les méthode(s) de la reconnaissance. La variante que nous préconisons est construite sur le principe selon lequel, afin d’assurer la portabilité du statut personnel au sein de l’Union européenne, la reconnaissance du statut cristallisé dans un État membre doit être la règle et les refus de reconnaissance l’exception, qu’il appartient à l’État d’accueil de justifier. En application de la méthode européenne de la reconnaissance, l’autorité d’accueil doit reconnaître le statut personnel d’une personne dès que celui-ci a été cristallisé dans un acte émanant d’une autorité publique d’un État membre, matériellement compétente pour ce faire, sans devoir vérifier au préalable sa validité. Elle peut cependant refuser de reconnaître le statut étranger si, et seulement si, ce refus apparaît nécessaire à la sauvegarde d’un intérêt fondamental de l’État d’accueil. Ce refus de reconnaissance prend alors la forme d’une exception européenne d’ordre public. Celle-ci systématise la mise en balance entre l’atteinte portée au droit à la permanence du statut personnel et l’intérêt légitime de l’État d’accueil poursuivi par le refus de reconnaissance. De surcroît, si l’État d’accueil est internationalement compétent pour ce faire, il peut annuler le statut étranger dans les mêmes conditions que l’État d’origine. Dans le cadre du contentieux de l’annulation, la validité du statut étranger est alors appréciée au regard des règles applicables dans l’ordre juridique d’origine, en tenant tout particulièrement compte des motifs de couverture éventuelle des nullités et de la titularité des personnes autorisées à soulever celle-ci. La méthode proposée pourrait, à notre sens, être traduite dans un Règlement européen, ce qui faciliterait incontestablement sa mise en œuvre. Afin de vérifier la faisabilité de la méthode européenne proposée, nous avons testé son application sur les situations potentiellement boiteuses épinglées lors d’un examen de droit comparé portant sur la circulation de quatre éléments du statut personnel au sein de quatre États membres. Les éléments du statut personnel sélectionnés étaient le nom de fa-mille, le mariage, le partenariat enregistré et le lien de filiation biologique. L’examen a porté sur les droits belge, français, allemand et anglais. Il a permis de mettre en évidence quelques-uns des atouts et faiblesses de la méthode proposée, que nous avons exposés dans le dernier chapitre de notre thèse et que nous résumons ci-dessous. La méthode européenne de la reconnaissance présente l’avantage d’offrir une réponse unique à la question de la portabilité du statut personnel. La distinction méthodologique traditionnellement retenue en fonction de la nature judiciaire ou non de l’acte à reconnaître est abandonnée. Elle permet d’éviter une grande partie des situations potentiellement boiteuses épinglées lors de notre examen de droit comparé, notamment en écartant le contrôle conflictuel et les autres motifs abstraits de refus de reconnaissance. La question de la qualification du statut établi à l’étranger se pose par conséquent avec moins d’acuité. Par ailleurs, elle met un terme à plusieurs débats actuels référencés au cours de nos travaux et apporte une réponse à des situations de vide juridique. Le postulat de la reconnaissance simplifie la circulation du statut personnel, puisque ce n’est qu’en cas de doute sur la compatibilité de l’accueil avec l’ordre public du for que l’autorité saisie procèdera à un examen plus approfondi de la situation qui lui est présentée. Dans la grande majorité des situations, le statut personnel circulera sans aucun réel contrôle au fond. L’approche concrète promue par la méthode proposée suscite cependant une difficulté particulière, qui n’existe pas, ou seulement dans une moindre mesure, dans l’application des règles abstraites de droit international privé étudiées. Il s’agit de la résolution des statuts inconciliables. Les approches traditionnelles, consistant à donner priorité au statut cristallisé dans l’ordre juridique d’accueil ou à appliquer un critère temporel, sont en effet écartées en faveur d’une approche concrète mettant en balance tous les intérêts en cause. S’agissant d’une méthode classiquement utilisée pour résoudre les conflits de droits fondamentaux, on connaît les difficultés et critiques auxquelles elle s’expose. De manière plus générale, la méthode européenne de la reconnaissance impose aux autorités nationales d’intégrer la logique européenne dans leur raisonnement, lorsqu’elles sont saisies de la question de la reconnaissance d’un élément du statut personnel cristallisé à l’intervention d’une autorité publique d’un État membre. Ce faisant, elle devrait réduire la survenance de statuts personnels boiteux et contribuer ainsi à faciliter la circulation des citoyens européens. Cette recherche s’inscrit dès lors à la croisée du droit de la famille, du droit international privé, du droit européen et des droits fondamentaux. [less ▲]

Detailed reference viewed: 42 (0 ULg)
Full Text
See detailExploration des structures représentationnelles sous-tendant les souvenirs et projections futures autobiographiques
Demblon, Julie ULg

Doctoral thesis (2016)

La capacité de se projeter mentalement dans le futur est une faculté de l’esprit humain qui reste encore mal comprise, bien qu’elle fasse l’objet d’un intérêt croissant dans la communauté scientifique ... [more ▼]

La capacité de se projeter mentalement dans le futur est une faculté de l’esprit humain qui reste encore mal comprise, bien qu’elle fasse l’objet d’un intérêt croissant dans la communauté scientifique. Des recherches récentes montrent que la mémoire épisodique est impliquée dans la capacité d’imaginer le futur, en délivrant les éléments sensoriels et contextuels issus d’expériences passées. Pour imaginer des événements futurs, l’individu recombine de manière flexible ces éléments afin de créer des représentations nouvelles et originales. Toutefois, nous en savons encore peu sur les autres structures qui sous-tendent les représentations du futur. Dans ce contexte, l’objectif général de cette thèse de doctorat fut de mettre en évidence les structures représentationnelles qui sous-tendent la capacité à anticiper le futur et à se souvenir du passé, et d’évaluer dans quelle mesure des principes organisationnels communs structurent ces deux types de représentations. Dans une étude précédente, nous avons montré que les représentations d’événements futurs viennent rarement à l’esprit des individus de façon isolée mais sont souvent associées à d’autres représentations sur base de leur thématique et de leur structure causale, formant ainsi des clusters d’événements (D’Argembeau & Demblon, 2012, Cognition, 125(2), 160-167). Ces données suggèrent que l’imagination du futur implique des connaissances de plus haut niveau de conceptualisation (telles que des connaissances relatives à des buts ou des connaissances abstraites sur soi-même) qui organisent la production des pensées futures épisodiques. Le premier objectif de ce travail de thèse fut d’examiner dans quelle mesure cette structuration des projections futures spécifiques sous forme de clusters est un mode d’organisation utilisé naturellement par les individus lorsqu’ils imaginent l’avenir. Nous avons ensuite utilisé la neuroimagerie fonctionnelle dans le but de préciser la nature des connaissances qui sous-tendent l’organisation des souvenirs et des projections futures en clusters d’événements. Dans une troisième étude, nous avons examiné les liens entre les réseaux de souvenirs et de projections futures et l’identité personnelle. Enfin, nous avons évalué dans quelle mesure la valeur affective des représentations contribue à l’organisation des souvenirs et des pensées futures. Dans l’ensemble, nos résultats montrent que les souvenirs et projections futures épisodiques sont rarement représentés de manière isolée, mais impliquent fréquemment des séquences d’événements autobiographiques véhiculant une signification personnelle de plus haut niveau. [less ▲]

Detailed reference viewed: 10 (0 ULg)
Full Text
See detailOn Vulnerability and Vulnerabilities of Incident Reporting
Rossignol, Nicolas ULg

Doctoral thesis (2016)

This PhD thesis – composed of a series of five papers tied together by an introduction and conclusions – explores the functioning of an Incident Reporting System used in a high-risk organization. It aims ... [more ▼]

This PhD thesis – composed of a series of five papers tied together by an introduction and conclusions – explores the functioning of an Incident Reporting System used in a high-risk organization. It aims at understanding how safety is actually constructed by and through this reporting system and what it actually does to the meaning of safety when it prescribes a set of sociotechnical practices. From a conceptual point of view, this PhD thesis departs from classical risk or vulnerability analyses which tend to measure factors in order to produce what are supposed to be “objective” results and “manageable” recommendations for decision makers. By relying on a constructivist understanding of vulnerability, this research explores and characterizes situations and events the consequences of which are ambiguous and the probabilities of which are uncertain. It thus broadens the scope of classical risk or vulnerability analyses and complements it with a qualitative and discourse-based attention to organizational, cultural and ethical questions. [less ▲]

Detailed reference viewed: 42 (9 ULg)
See detailModeling in Air Transportation: Cargo Loading and Itinerary Choice
Lurkin, Virginie ULg

Doctoral thesis (2016)

We examine two problems as part of this dissertation. The first is a cargo loading problem. The aim is to load a set of containers and pallets into a cargo aircraft that serves multiple airports. Our work ... [more ▼]

We examine two problems as part of this dissertation. The first is a cargo loading problem. The aim is to load a set of containers and pallets into a cargo aircraft that serves multiple airports. Our work is the first to model cargo transport as a series of trips consisting of several legs at the end of which pickup and delivery operations might occur. This problem is crucial for airlines because in an attempt to reduce their costs, most airlines prefer to load as many containers as possible, even if all the loaded containers do not have the same final destination. Our results demonstrate that it is possible to quickly find near optimal or excellent feasible loading plans, and that our approach leads to substantial savings with respect to typical manual approaches currently used in practice. The second problem we examine involves the estimation of itinerary choice models that include price variables and correct for price endogeneity using a control function that uses several types of instrumental variables. The motivation for developing these models is to demonstrate the importance of accounting for price endogeneity and to estimate different price sensitivities as a function of advance purchase periods. This is important as the airline industry can use our results to incorporate different customer segments as revealed through high-yield and low-yield booking curves when evaluating the profitability of airline schedules. Results based on Continental U.S. markets for May 2013 departures showed that models that fail to account for price endogeneity overestimate customers' value of time and result in biased price estimates and incorrect pricing recommendations. The advanced models estimated (nested logit and ordered generalized extreme value (OGEV) models) are shown to outperform the baseline multinomial logit model with regard to statistical tests and behavioral interpretations. Additionally, results show that price sensitivities vary as a function of advance purchase periods, with those purchasing high-yield products being less price sensitive than those purchasing low-yield products (across any advance purchase periods) and those purchasing closer to departure being less price sensitive. Results also indicate that inter-alternative competition is strong for itineraries that share similar departure times. Finally, as part of the itinerary choice model developed in this dissertation, we estimate highly refined departure time of day preferences. Results are intuitive and show that departure time of day preferences vary across many dimensions including the length of haul, direction of travel, number of time zones crossed, departure day of week, and itinerary type (i.e., outbound, inbound, and one-way itineraries). To the best of our knowledge, these curves represent the most refined publicly-available estimates of airline passengers' time of day preferences. [less ▲]

Detailed reference viewed: 72 (9 ULg)
Full Text
See detailSexual attraction in lady beetles: fundamentals and applications
Fassotte, Bérénice ULg

Doctoral thesis (2016)

Sustainable agriculture relies on the development of environmentally friendly methods of crop production. Therefore, alternative solutions are required to decrease insecticide use and to promote the ... [more ▼]

Sustainable agriculture relies on the development of environmentally friendly methods of crop production. Therefore, alternative solutions are required to decrease insecticide use and to promote the efficacy of natural enemies against insect pests. Investigating the sexual behavior of lady beetles is of practical relevance, because these insects could be used to reduce plant-feeding insect populations in crop fields by taking advantage of their predatory behavior. In this context, the objective of this PhD thesis was twofold: (1) a fundamental research that focuses on the identification of the sex pheromone of Harmonia axyridis (Pallas) and (2) an applied approach aimed at elaborating semiochemicals slow-release dispensers with these compounds, in order to attract individuals in cultivated fields. We have demonstrated that virgin females of H. axyridis display a typical male-calling behavior in presence of prey, which is associated with the release of a pheromonal blend that is highly attractive for conspecific males. Dynamic headspace sampling and subsequent chemical analyses allowed the characterization of this sex pheromone. Finally, we focused on the development of a formulation releasing a combination of semiochemicals that attract aphid predators. The formulation, composed of alginate beads, was optimized under laboratory conditions. The release rate of the formulation was assessed by dynamic headspace sampling coupled with adsorbent trapping. The formulation was efficient at attracting two natural enemies of aphids. All these results are discussed in the context of sustainable agriculture, with the use of semiochemicals, and especially pheromones, as potential tools to enhance current cropping systems. In near future, the application of such molecules, based on strong knowledge of insect olfaction, is expected to increase considerably with the development of new methods aimed at attracting predators and/or parasitoids. In addition, improvements of experimental devices, such as the elaboration of slow release dispensers, are suggested in the last chapter of this PhD thesis. [less ▲]

Detailed reference viewed: 67 (33 ULg)
Full Text
See detailImpact de l'incertitude sur la gouvernance des institutions de microfinance: cas de coopératives burundaises
Niyungeko, Thadée ULg

Doctoral thesis (2016)

The microfinance sector has attracted increasing attention particularly in literature and in political circles in recent years. Microfinance is seen as a key means for the poors to access to financial ... [more ▼]

The microfinance sector has attracted increasing attention particularly in literature and in political circles in recent years. Microfinance is seen as a key means for the poors to access to financial services. Nevertheless, one of the challenges of microfinance institutions lies in their governance. To study the governance of microfinance institutions, many authors recommend to consider not only their diversity related to their natures and their missions, but also the context of the country in which they operate. However, existing works have not fully taken into account the contextual factors in the study of the governance of MFIs. This thesis contributes to bridge these gaps. It is in this sense of a specific and suitable approach to microfinance institutions. It analyzes the impact of the uncertainty related to an internal armed conflict in Burundi cooperatives. This research shows that face of uncertainty, policymakers are faced with the decision-making problems in compliance with the rules. Conflicts of interest arise, the paradoxes in the roles of directors or in inter-organizational relationships are observed. The results of this research also show the limits of volunteer principle in cooperative organizations in times of uncertainty. To cope with uncertainty, cooperatives undertaking various coping strategies despite their organizational similarities. They further develop inter-organizational relationships in search of legitimacy and scope of expression. Belonging to the network and the pressures of supervisor push these organizations to adopt isomorphic structures and practices. This thesis is a first milestone in the studies on the governance of cooperatives under uncertainty. It goes beyond the Burundian context by formulating hypotheses to be tested in future studies and in other places. [less ▲]

Detailed reference viewed: 54 (10 ULg)
Full Text
See detailLe billonnage cloisonné en agriculture des montagnes: évaluation et facteurs d'acceptation. Cas des Hauts Plateaux de l'Ouest-Cameroun
Djoukeng, Henri Grisseur ULg

Doctoral thesis (2016)

In the Western Highlands of Cameroon as in all other regions of the world where mountain agriculture is practiced, erosion and runoff pose a real threat to the sustainable preservation of natural ... [more ▼]

In the Western Highlands of Cameroon as in all other regions of the world where mountain agriculture is practiced, erosion and runoff pose a real threat to the sustainable preservation of natural resources. Generally, plots located on the slopes of the mountains in the Western Highlands have either become less productive or totally unproductive; this situation is exasperated by the scarcity of arable land which is largely attributed to cultural practices that do not take into account soil and water conservation methods. To better quantify the impacts of erosion and runoff on the different functions assigned to agriculture and agricultural holdings, this thesis has implemented tied ridging which is an unused soil and water conservation technique. We have thus compared the effectiveness of the existing soil preparation methods (ridging along the steepest slopes and flatbed cultivation) with tied ridging on two operating slopes namely 11% and 29%. The results showed a significant difference between the current practice (flatbed and ridging along the steepest slopes) and tied ridging in terms of soil loss (p = 0.003), yields (p = 0.003), and runoff water (p < 0.001). Under sole cropping of potato on a hectare of land, the tied ridging led to: (i) increase in populations of cultivated plants by 7%, (ii) significant reduction of runoff (lowered by a factor of seven) and soil loss (lowered by a factor of five), (iii) increase in yields by 80%, (iv) increase in farmer’s profitability by approximately 908388 FCFA.ha-1. The tied ridging needed 41% extra work regardless the slope of the land on which it was practiced. The tied ridging showed undeniable advantages: the stress of additional work was offset by the gain in yields for producer; additional work created additional job opportunities for the community; and tied ridging improved the conservation of soil and water for a healthy environment. Although the technique has several advantages, the provision of financial means for its implementation could be a negative point, because family labor supply is generally insufficient for its realization and the hired labor is expensive. Further work was dedicated to measuring the rate of adoption of the tied ridging technique and analysis of the determinants for adoption. The study showed that exploiting land ownership by farmers is a key factor in the implementation of soil conservation techniques. The results showed tied ridging adoption rates of 93% and 62% for dignitaries and other farmers respectively. Overall, access to land, operating slopes, and adoption of soil and water conservation techniques were significantly influenced by agronomic potentials of plots and socio-economic situation of farmers (p <0.05). Finally, in order to quantify the overall impact of tied ridging on the quality of surface water, we measured the proportion of sediments migrating from plots under the three soil preparation methods and entering to the river’s bed. The collected and measured sediments consisted of soil, plant residues, and other wastes (chemical packages, plastic casing used for irrigation, and food packages). The results showed that tied ridging cultivation method significantly reduced siltation of the Méloh River (p<0.05). Compared to 2012 and 2013, quantities of sediment decreased by 66% in 2014, the year in which the tied ridging technique was adopted on 75% of the plots. Thus the flatbed and ridging along the steepest slopes soil preparation methods are the principal cause of siltation and pollution of the Méloh River. The results of this research led to the following prospective approaches for improvement: (i) test the tied ridging technique with other crops and with different inter mounds’ spacing, (ii) study the facilitation of access to credit and creating farmer's organizations for promoting the adoption of tied ridging, (iii) test other soil and water conservation techniques such as live hedges, direct-sowing mulch-based crop (agroecology), and agroforestry, and (iv) conduct general limnologic studies of watersheds. The general limnology studies the surface waters according to their seasonal variations, and their physico-chemical and biological aspects. [less ▲]

Detailed reference viewed: 86 (23 ULg)
See detailLes femmes entrepreneures au Maroc : Quels sont les facteurs individuels et contextuels qui influencent leur activité ? Une étude comparative entre trois profils de femmes entrepreneures
Salman, Noura ULg

Doctoral thesis (2016)

L’entrepreneuriat féminin, en tant que vecteur de croissance et d’emploi suscite l’intérêt des décideurs politiques, économiques et académiques (De Bruin et al. 2007 ; Arasti, 2008 ; Lebègue, 2010 ... [more ▼]

L’entrepreneuriat féminin, en tant que vecteur de croissance et d’emploi suscite l’intérêt des décideurs politiques, économiques et académiques (De Bruin et al. 2007 ; Arasti, 2008 ; Lebègue, 2010 ; Hugues et al. 2012). Dans cette perspective, notre thèse a comme objectif d’identifier les principaux facteurs individuels/personnels et contextuels susceptibles d’influencer l’activité entrepreneuriale des femmes marocaine. A partir d’une étude comparative entre trois profils de femmes entrepreneures : les femmes chefs d’entreprises, les femmes en professions libérales et les femmes coopératrices, nous avons cherché à comprendre comment un ensemble de facteurs peuvent être favorable ou défavorable à l’activité entrepreneuriale des femmes marocaines. Dans ce cadre, une série d’interviewés qualitatives (60 interviews) ont été réalisées entre 2011 et 2013. Pour réaliser cette enquête nous nous somme appuyés sur un ensemble de propositions de recherches élaborées à partir de notre cadre théorique. En s’inscrivant dans une perspective féministe, notre analyse s’appuie essentiellement sur l’analyse du genre. Cinq groupes de facteurs ont été retenus pour notre recherche, à savoir : les facteurs personnels, les facteurs familiaux, les facteurs institutionnels, les facteurs professionnels ainsi que les facteurs socioculturels. Notre analyse permet à la fois d’appréhender l’influence des facteurs ci-dessus sur l’activité entrepreneuriale des femmes dans le contexte marocain mais, aussi, la particularité de leur expérience via une lecture en termes de genre. Nous résultats indiquent, que des facteurs personnels, en particulier les motivations personnelles, et les facteurs familiaux (le soutien du conjoint et le réseau familial) constituent les principaux leviers pour les femmes entrepreneures marocaines. Par contre les facteurs institutionnels (l’administration et le financement externe), les facteurs professionnels notamment les clients et enfin les facteurs socioculturels sont les principaux freins pour les femmes entrepreneures marocaines. Nous résultats indiquent ainsi, des caractéristiques similaires aux trois groupes de femmes entrepreneures. Mais également, des différences importantes entre les trois catégories. Cela témoigne de la réalité plurielle de l’entrepreneuriat féminin au Maroc, qui peut susciter un intérêt auprès des praticiens et des théoriciens de ce phénomène. [less ▲]

Detailed reference viewed: 76 (5 ULg)
Full Text
See detailSTUDY AND CHARACTERIZATION OF MAGNETIC AND MULTIFERROIC MATERIALS BY FIRST-PRINCIPLES CALCULATIONS
Garcia Castro, Andrés Camilo ULg

Doctoral thesis (2016)

In the last fifteen years, multifunctional materials, and more specifically, multi- functional oxides have been widely studied due to its wide range of properties. Properties that go from ... [more ▼]

In the last fifteen years, multifunctional materials, and more specifically, multi- functional oxides have been widely studied due to its wide range of properties. Properties that go from superconductivity to ferroelectricity passing through mag- netism and multiferroism have been reported. Nonetheless, the fluoride family was left aside and little information is known about its possible ferroelectricity or mul- tiferroism. In this Ph.D thesis, we explored the electronic, vibrational, structural and magnetic properties of fluoride perovskite-based compounds. To such pur- poses, We performed ab-initio calculations based in the density-functional theory (DFT) as implemented in VASP and CRYSTAL codes. Our first step was to perform vibrational analyses in a large set of fluoroper- ovskites ABF3. Based on the results, we proposed a model that establishes an A-site geometrically driven ferroelectric vibrational instability in fluorides. Our studies reveal a different behavior as a function of isotropic pressure for NaBF3 with respect to oxides (e.g. BaTiO3) with B = Ca, V, Mn, and Zn. For these compounds we found an increase of the ferroelectric instability as a function of hydrostatic pressure. This probably due to the “transformation” of eigendisplace- ments responsible for the mode that creates the corresponding instability. In particular, an increase of ionic A-site radii present a strong influence in FE-polar instability. We also have shown, based on our first-principles calculations and symmetry theory analysis that all post-perovskites ABX3 with an active magnetic B-site cation can exhibit a noncollinear magnetic configuration, which happens to be allowed by symmetry. With these findings, the magnetic properties found exper- imentally were clarified for this particular high-pressure phase perovskite found at the Earth’s mantle. Additionally, We have predicted that NaMnF3 suffers a structural phase transition under pressure to a post-perovskite phase, where non- collinear ferromagnetism and large magnetic moment components are obtained within this high-pressure phase.. Going beyond, We have shown that it is possible to achieve multiferroic-induced state in NaMnF3 under epitaxial strain at compressive or tensile strain. We found a nonlinear behavior of the ferroelectric instability as well as a non-linear piezo- electric response as a function of epitaxial strain. The later completely different as the one found in oxide perovskites. Similarly, an out-of-plane polarization was observed, a property that has not been observed in oxides. We observed a Na + Mn sites cooperative ferroelectric ordering for compressive strain against a pure A-site geometrically driven ferroelectricity at tensile values of the ac-strain. Magnetic ordering reveals a non-collinear ground state with the GzAxFy repre- sentation. Even more interesting, and non-linear magnetoelectric coupling was found under the strained Pna1 ground state becoming the first known multifer- roic/magnetoelectric perovskite fluoride. Later, in order to go further, We studied the electronic and structural proper- ties of novel heterostructures based on oxyfluorides (KTaO3)n/(KBF3)l B = Zn and Ni interfaces. We found that the orbital levels splitting at the interfaces is strongly modified by the O–B–F coordination. The polar catastrophe phenomena also takes place in the oxyfluoride interfaces similarly to oxide heterostructure, however, we found that less number of layers are needed in order to achieve the insulator-to-metal transition when comparing to SrTiO3/LaAlO3 superlat- tices. We observed that the magnetism in the KTaO3/KNiF3 exhibits a moment magnitude modulations. Nevertheless, the magnetic structure keeps the G-type antiferromagnetism such as in the bulk former compound. Surprisingly, we ob- served a large k3-Rashba type splitting in at the oxyfluoride interfaces, at least four times larger than the one reported in SrTiO3/LaAlO3 interface and twice of the KTaO3-based transistor. In conclusion, we observed that fluorides-perovskites are good prototypes for multifunctional properties as oxides. Therefore, based on the results reported in this thesis, we expect that experimentalist and theoreticians can be motivated in characterization of fluorides, which can lead to a new set of unexplored materials with potential novel applications in electronics. [less ▲]

Detailed reference viewed: 77 (6 ULg)
Full Text
See detailDocteur
Poskin, Antoine ULg

Doctoral thesis (2016)

During summer 2011, cattle presented severe hyperthermia combined with dropped milk yield and diarrhoea from unknown origin. In October 2011, blood was collected from cattle presenting these clinical ... [more ▼]

During summer 2011, cattle presented severe hyperthermia combined with dropped milk yield and diarrhoea from unknown origin. In October 2011, blood was collected from cattle presenting these clinical signs in Schmallenberg, a small city in West Germany. A new Orthobunyavirus, responsible for these unspecific clinical signs was identified and named Schmallenberg virus (SBV). Upon November 2011, an epizootic outbreak of abortion, stillbirths and malformed new-born was observed in bovine, ovine and caprine herds in Europe due to transplacental transmission of SBV to the foetus. The SBV vectors are small hematophagous midges of the gender Culicoides. This work contributed to estimate the impact of the SBV epidemic in Belgium (Study 1). On the basis of farmer’s observations, between 0.5% and 4% of calves were aborted, stillborn or malformed due to SBV in 2011-2012. Abortions and stillbirths were not clear consequences of the SBV outbreak in cattle. In sheep, between 11% and 19% of lambs were aborted, stillborn or malformed due to SBV in 2011-2012. Deformed animal was the most important finding of SBV outbreak at herd level and an essential condition for the farmer to send suspected samples to the National Reference Laboratory (NRL) for SBV analysis. The results gathered from the study indicate that SBV surveillance and monitoring should be implemented by SBV RNA detection with rRT-PCR in organs collected from stillborn and deformed calves and lambs born in big herds. The high impact of SBV highlighted in the Study 1 was putatively explained by unknown host supporting the SBV activity. In this respect, the role of pigs had never been evaluated. This was essential considering the suggested role of the domestic pigs in the life- cycle of the SBV-closely related Akabane virus (AKAV) (Huang et al., 2003). The absence of RNAemia after experimental infection of piglets with SBV realized in the Study 2 of the i thesis suggests the absence of obvious role of domestic pigs in SBV life-cycle. The absence of RNAemia is indeed a strong indication that further spread of SBV from the pigs to the Culicoides during a blood meal of the vector is not likely to occur, therefore making impossible an SBV transmission. The limited and temporary seroconversion observed after SBV inoculation in only half of the inoculated piglets and the absence of seroconversion reported in a limited number of field collected samples support this consideration. To prevent SBV progression, it was crucial to further study the pathogenesis of SBV. The Study 1 proved that the most important clinical impact of SBV was the consequence of the malformed new-born; hereto it was particularly crucial to improve the knowledge on the development of the SBV-related teratogenic effects. In this respect, experimental infection of pregnant sheep with SBV constituted an appropriate research approach. An experimental model was therefore essential to standardize. This thesis contributed to the standardization of in vivo experiments (in collaboration with another working group) by determining the minimum infectious dose of an SBV infectious inoculum. This reference infectious serum must contain approximately 20 TCID50 to induce a homogeneous effective infection in sheep. This dose is rather low and could be inoculated by a single Culicoides under natural conditions. Beyond this minimum infectious dose, no dose dependent effect was observed in productively inoculated ewes, either in the duration of the RNAemia, the quantity of SBV RNA detected by rRT–PCR in the blood, or in the number of SBV RNA copies present in the organs collected at necropsy. The experimental model developed (partly) in the Study 3 was used to inoculate pregnant ewes at day 45 and 60 of gestation, and increase the knowledge on SBV transplacental transmission. The inoculation induced the persistence of SBV RNA in placental organs until birth. Schmallenberg virus RNA was recovered from the organs collected at birth from the lambs of both groups. However, the chance to obtain SBV RNA positive placental ii organs was significantly higher when the infectious inoculum was inoculated at day 60 of gestation. Positive organs in lambs included CNS and muscle, but no malformation was observed in new-born lambs. This absence of malformations suggests that SBV inoculation must occur earlier than the day 45 of gestation to produce teratogenic effects in sheep. Also, the persistence of SBV RNA in the foetal envelope is indicative of a putative mean for SBV overwintering. The Study 4 highlighted a 6 month persistent seroconversion in the absence of SBV surinfection. In the meantime, SBV circulation drastically dropped on the field and the absence of SBV circulation could induce the sheep to become seronegative under natural conditions. In the Study 5, the experimental model developed in the Study 3 was used to demonstrate that one single SBV inoculation can induce a protective immunity in sheep that persists during a minimum period of 15 months. This experiment highlights that 2 successive periods of SBV circulation, spared of one year, is not likely to induce malformations on the field the second year. Based on the experience gathered with the closely related AKAV, recurrent outbreaks of congenital events can be expected for a long period. Vaccination of seronegative animals could be used to prevent the deleterious effects of SBV in case of SBV re-emergence. During this epidemic, different surveillance approaches including syndromic surveillance, sentinel herd surveillance, cross-sectional seroprevalence studies and pathogen surveillance in vectors have proven their utility and complementarity and should be considered to continue in the future in order to monitor the SBV dynamic. [less ▲]

Detailed reference viewed: 35 (5 ULg)
Full Text
See detailDevelopment and validation of analytical methods based on GC-MS/MC Triple Quadrupole instrument for the analysis of POPs in food and feed matrices
Calaprice, Chiara ULg

Doctoral thesis (2016)

This thesis focused on the development and validation of analytical methods for the de-tection and quantification of Persistent Organic Pollutants (POPs) in biological matrices, namely food and feed ... [more ▼]

This thesis focused on the development and validation of analytical methods for the de-tection and quantification of Persistent Organic Pollutants (POPs) in biological matrices, namely food and feed samples. POPs are a group of chemical compounds listed after the Stockholm Convention in 2001, with demonstrated toxicity and dangerousness for envi-ronment, animals and humans. In this work of thesis, special attention was reserved to some selected POPs: polychlo-rodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), usually referred to as “dioxins”, and polychlorinated biphenyls (PCBs), as there is a big concern about these contaminants in Taranto, a city in the Southern Italy very close to Bari, my home town. Taranto, indeed, is characterized by a large industrial area with a steel mill, several incin-erators and a refinery in few kilometre radius (Di Leo et al., 2014). This work has been done in collaboration with the University of Liège (Belgium) where a consolidated exper-tise in the field of POP measurements was available, especially in terms of dioxin anal-yses. In Chapter 1 the main steps, from sample preparation to data elaboration, of a validated confirmatory method for dioxin and PCB detection in food and feed using gas chromatog-raphy coupled to tandem mass spectrometry Triple Quad instrument (GC-MS/MS Triple Quad) have been described. This method was developed at the University of Liège in the framework of the last updates of the EU Regulation that in 2014 allowed confirmatory quantitative analysis of dioxins with Triple Quad. This method was the starting point of this work of thesis, because it was used for all dioxin and PCB quantifications. In Chapter 2 and chapter 3 alternative clean-up approaches for dioxin analysis in fatty food matrices have been developed using different automated systems. These works have been done in the framework of solvent and time saving for high throughput analytical methods in dioxin analysis. In chapter 2, an already existing automated system, DEXTechTM from LCTech GmbH (LCTech GmbH, Bahnweg 41, 84405 Dorfen, Germany) was used for sample clean-up, but a completely new clean-up approach was developed with this. GC-MS/MS Triple Quad instrument, as well as Magnetic Sector High Resolution Mass Spectrometry (HRMS) instrument were employed for final quantification, to demonstrate the suitability of our newly developed clean-up approaches whatever the instrumental detection. In Chapter 3 PowerPrepTM automated system from Fluid Management System (FMS Inc., 580 Pleasant Street, Watertown, MA 02472, USA) was used and our routine sample clean-up approach was modified in order to enhance the efficiency and to reduce cost and solvent consumption of the analysis. In Chapter 4 the main method for dioxin analysis was adapted for the integration of Dechloranes in the list of the analytes targeted in the regular control for dioxins in food and feed. Dechloranes are a family of 6 organo-chlorinated compounds with structure similar to Mirex, also called Dechlorane, a POP listed in the Stockholm convention. Dechloranes have been found in human blood of people from Europe (Brasseur et al., 2014) and in this work an analytical method for Dechlorane detection was developed and validated to investigate food as a possible route of exposure for humans in Europe, where no production plant has been identified so far. The analytical method was used to analyse 88 food and feed real sample and to give an idea of Dechlorane daily dietary intake. [less ▲]

Detailed reference viewed: 50 (6 ULg)
Full Text
See detailStudy of the genetic structure of the African buffalo populations (Syncerus caffer): Impact of its high mobility and of the population fragmentation on its distribution and its interactions with humans
Smitz, Nathalie ULg

Doctoral thesis (2016)

The African continent still hosts a unique diversified megafaunal community. However, phylogeographical patterns of African species have not yet been largely studied, as compared to the North American and ... [more ▼]

The African continent still hosts a unique diversified megafaunal community. However, phylogeographical patterns of African species have not yet been largely studied, as compared to the North American and European species. Moreover, nowadays, the African ecosystems suffer of considerable anthropogenic pressures and of severe climatic modifications. Wildlife population fragmentation resulting from habitat loss, drought, poaching and diseases is currently threatening many African species survivals. The present thesis aimed at investigating the phylogeography and the population genetic structure of the African buffalo (Syncerus caffer) at different spatio-temporal scales (phylogeographical scale vs demographic scale), based on different molecular markers (mtDNA D-Loop region, 17 microsatellites and a large set of ‘Single Nucleotide Polymorphisms’ (SNPs)). The African buffalo is an emblematic key species and provides a powerful model to enhance our understanding of the African biogeography and the species conservation requirements. The aim of the first part of the present work was to reconstruct the evolutionary history of the African buffalo based on the study of the mtDNA D-Loop hypervariable region. More particularly, we aimed at studying the impact of the Quaternary climatic fluctuations on the species distribution (i.e. phylogeographical scale). Moreover, one of our purposes was also to investigate the taxonomic controversies linked to the extreme within species morphological variability, using molecular tools. From a sample set including all four morphologically recognized subspecies roaming the sub-Saharan African continent (hereafter called ecophenotypes), two taxonomic units were supported by genetics. The genetic discontinuity was located between the West-Central (S. c. nanus, S. c. brachyceros and S. c. aequinoctialis) and the South-Eastern populations (S. c. caffer). The low amount of genetic differentiation within each of these two units, or lineages, was attributed to a recent (in evolutionary term) Pleistocene expansion in both lineages, with rapid adaptation to a variety of habitats. Using both microsatellites and a large set of SNPs, the second part of the present thesis aimed at investigating the impact of human activities and recent climatic changes on the population structure of the species (i.e. demographic scale). While mtDNA did not allowed to distinguish finer sub-structuration within the two identified lineages, suggesting high female gene flow at an evolutionary timescale, these last molecular markers allowed to identify eight different populations at the continental level: two in West-Central Africa, three in Eastern and three in Southern Africa. Both ancient (Neolithic revolution) and recent anthropogenic activities were proposed to have shaped the demographic population structure observed in Southern and Eastern Africa. Recently, two of these populations were shown to be under significant genetic drift, following severe demographic bottlenecks. In these two cases, the sharp reduction in the size of the populations was proposed to be linked to disease eradication campaigns and to overharvesting during civil wars. Nevertheless, they did not display a significant loss in heterozygosity, indicating that they are still genetically healthy. Interestingly, at the contact region between the S. c. caffer and the S. c. aequinoctialis savanna ecophenotypes, a population displaying a shared genetic pool was also identified, corroborating the existence of hybrids between the different forms (intermediate morphological characteristics). In conclusion, using various genetic approaches and molecular markers, the present work gained insights into the taxonomy and the evolutionary history of the African buffalo, as well as in its conservation management requirements. [less ▲]

Detailed reference viewed: 33 (9 ULg)
See detailDéveloppement de procédés sol-gel de fabrication de matériaux de batterie
Eskenazi, David ULg

Doctoral thesis (2016)

Différents procédés, installations et moyens d'analyse ont été développés pour la fabrication de matériaux de batterie Li-ion par procédé sol-gel. Leur objectif est de faciliter l'utilisation industrielle ... [more ▼]

Différents procédés, installations et moyens d'analyse ont été développés pour la fabrication de matériaux de batterie Li-ion par procédé sol-gel. Leur objectif est de faciliter l'utilisation industrielle de ces matériaux. Il s'agit d'un réacteur continu de fabrication de xérogels de carbone sous forme de billes, d'un réacteur de nitruration de phosphates, et d'une technique d'analyse thermique couplée à de la spectrométrie de masse. [less ▲]

Detailed reference viewed: 25 (1 ULg)
Full Text
See detailModel-Based Prediction of the Response to Vascular Filling Therapy
Pironet, Antoine ULg

Doctoral thesis (2016)

Vascular filling is one of the most frequent interventions in intensive care units. Its expected effect is to increase cardiac output. However, this increase is only observed in approximately 50 % of ... [more ▼]

Vascular filling is one of the most frequent interventions in intensive care units. Its expected effect is to increase cardiac output. However, this increase is only observed in approximately 50 % of cases. In addition, excessive vascular filling can lead to deleterious effects, such as pulmonary oedema, which increase length of ventilation, stay, mortality and cost. Clinicians are thus looking for indices to provide a priori knowledge of the effect of vascular filling. This thesis focuses on a mathematical model-based approach to predict the response to vascular filling. Mathematical models are sets of equations representing the behaviour of a given system as, for instance, the cardiovascular system. To understand the concept of vascular filling, basic elements of cardio-vascular anatomy and physiology are presented in the first part of this thesis. Then, fur- ther details about vascular filling therapy are given, as well as the current indices used by clinicians to predict its effects. The static indices are easy to obtain, but do not perform well. The dynamic indices, based on cardio-pulmonary interac- tions, perform better, but are difficult and highly invasive to implement clinically. A new index, total stressed blood volume, also seems to perform well, but is not easy to obtain clinically. This work develops and then uses models of the cardio- vascular system to make this parameter available to clinicians. Building on the elements of physiology provided in the first part, the second part of this thesis describes ways to model the components of the cardio-vascular system as lumped elements, such as chambers, valves and resistances. Two mod- els of the cardio-vascular system, comprising respectively three and six cham- bers, are built from such elements. These two models involve a small number of parameters, including the total stressed volume in the model. The third part of this thesis describes the potential and methods to identify the parameters of the two cardio-vascular system models. Parameter identifica- tion aims at finding the parameter values that make model simulations as close as possible to measured data. The available data is thus first described, accord- ing to whether it is collected in an experimental laboratory or an intensive care unit. Then, it is mathematically demonstrated that all model parameters can the- oretically be identified from data available in an intensive care unit. However, practically speaking, some parameters are difficult to identify, because they have little influence on the simulations, or have the same effect as other parameters. Fi- nally, computational methods to perform parameter identification are presented and compared. The last part of this thesis presents two applications of the cardio-vascular system models to experimental data. First, all parameters of the six-chamber cardio-vascular system model are identified from data recorded during a preload reduction experiment. This result provides the first quantitative validation of the six-chamber model in transient conditions. Second, all parameters of the three-chamber cardio-vascular system model, including total stressed volume, are identified from data recorded during vascular filling experiments. The total stressed volume parameter is shown to be systematically related to the change in cardiac output after vascular filling. This last index thus provides, for the first time, a model-based means of predicting the response to vascular filling. [less ▲]

Detailed reference viewed: 50 (17 ULg)
Full Text
See detailApplication de l’échographie à l’étude de la dynamique folliculaire lors de l’oestrus induit chez la vache Azawak au Niger
Moussa Garba, Mahamadou ULg

Doctoral thesis (2016)

Le Niger dispose d’énormes potentialités en matière d’élevage bovin notamment. Mieux exploitées et gérées, elles pourraient améliorer de manière très significative les performances des races locales. Les ... [more ▼]

Le Niger dispose d’énormes potentialités en matière d’élevage bovin notamment. Mieux exploitées et gérées, elles pourraient améliorer de manière très significative les performances des races locales. Les faibles performances de production et de reproduction qui caractérisent le bétail nigérien sont imputables à plusieurs facteurs, notamment les déficiences alimentaires, le mauvais état sanitaire et le faible potentiel génétique des races locales. L’alimentation du cheptel dont dépendent les productions, reste largement tributaire du régime des pluies dont les faibles quantités généralement enregistrées rendent aléatoire la production fourragère. De même, le faible taux de couverture sanitaire entraine la persistance de certaines maladies (PPCB, pasteurellose, tuberculose, parasitoses, mammites..) contribuant ainsi à la baisse des performances de production et de reproduction. La race bovine Azawak, la meilleure laitière produit à peine 7 à 8 litres de lait par jour. Au cours de ces dernières décennies, plusieurs stratégies et programmes de développement ont été élaborés et mis en oeuvre en vue de valoriser les productions animales. Cependant, la mise en oeuvre de ces stratégies et programmes de développement n’a pas permis d’améliorer la performance du secteur de l’élevage et certains indicateurs comme la consommation de viande et de lait par habitant ont diminué de manière drastique. En dépit d’un cheptel bovin numériquement important (+ de 11 millions de têtes), le Niger enregistre un déficit laitier important. La production locale est loin de couvrir les besoins de la population. La présente étude est une contribution visant à terme à augmenter la production laitière par le recours à l’insémination artificielle dont il restait cependant à : - faire le point sur les caractéristiques et performances de reproduction de Bos indicus ; - évaluer les caractéristiques physiologiques et pathologiques du tractus génital de la femelle Bos indicus ; - décrire par échographie les caractéristiques de la croissance folliculaire et de l’ovulation chez des femelles Azawak dont l’oestrus a été induit par une PGF2α ou par des progestagènes. La documentation sur les caractéristiques et performances de reproduction des zébus africains est peu nombreuse. Ainsi, une synthèse a été réalisée pour dresser l’état des lieux des connaissances dans le domaine de la reproduction de Bos indicus. Compte tenu des faibles performances de reproduction de Bos indicus, et pour recourir à l’insémination artificielle, divers traitements hormonaux sont envisagés. Ce travail a également actualisé les résultats potentiels offerts par l’insémination artificielle réalisée sur chaleurs naturelles ou induites. L’infécondité est une des caractéristiques de l’élevage bovin en Afrique se traduisant par un allongement de l’âge du premier vêlage et de l’intervalle entre vêlage. Elle limite le progrès génétique et la rentabilité des élevages de Bos indicus. Pour comprendre si les pathologies du tractus reproducteur constituent un facteur de risque d’infécondité dans le bétail nigérien, une étude a été conduite à l’abattoir de Niamey au Niger. Elle a concerné 500 tractus génitaux de 500 femelles zébus (Bos indicus) appartenant à quatre races bovines (Azawak, Bororo, Djelli, Goudali). Ces vaches et génisses, âgées en moyenne de 8 ± 2,5 ans, ont eu une note d’état corporel moyenne de 1,6 ± 0,6 et un poids moyen de carcasse de 113 ± 21 kg. Aucune différence significative n’a été observée entre les races étudiées en ce qui concerne le diamètre du col (3,4 ± 1,1 cm), la longueur du col (8,1 ±2,5 cm) et des cornes (21,6 ± 5,2 cm), le diamètre des cornes (1,6 ± 0,5 cm), la longueur et la largeur de l’ovaire droit (19,8 ± 4,4 mm et 11,2 ± 3,8 mm) et de l’ovaire gauche (18,8 ± 4,5 mm et 10,2 ± 3,3mm) et le poids des ovaires gauche et droit (2,5 ± 1,6 et 2,9 g ± 1,8 g respectivement). Ces données sont d’une manière générale, inférieures à celles classiquement rapportées pour le genre Bos taurus. Diverses pathologies de l’appareil génital (kystes, infections utérines, free-martinisme, pyomètre) ont été observées sur 10,4 % des tractus génitaux. La fréquence observée des pathologies donne à penser qu’elles ne constituent pas un facteur de risque majeur de l’infécondité. Ce résultat à amener à étudier l’effet des traitements hormonaux sur la croissance folliculaire et l’ovulation. En effet, la croissance folliculaire jusqu’à l’ovulation après synchronisation et induction des chaleurs au moyen de PGF2α et de progestagènes a été appréciée par échographie chez 42 vaches en lactation de race Azawak. Ces animaux issus de la station de Toukounous ont été ensuite inséminés deux fois (à 12 heures et à 24 heures) 5 après la détection de l’oestrus sur respectivement 16 et 11 femelles traitées à la PGF2α et aux progestagènes. Cette investigation à permis de noter les constats suivants : Les taux moyens d’induction ont été de 81 % dans les deux traitements. Le délai moyen d’apparition de l’oestrus est apparu significativement plus long après injection d’une PGF2α (84,8 ± 26,0 heures) qu’après retrait du PRID (59,2 ± 5,8 heures). La durée moyenne de l’oestrus a été plus courte après son induction au moyen de la PGF2α (12,6 ± 2,6 heures) que du progestagène (22,9 ± 2,7 heures) ; Le délai d’ovulation à partir des chaleurs n’a pas été significativement différent chez les animaux traités à la PGF2α (30,3 heures) et aux progestagènes (28,4 heures) ; Le taux de gestation après une injection de PGF2α (31,2 %) a été inférieur à celui obtenu après utilisation du protocole à base de progestagènes associé à une injection de PGF2α et d’eCG (54,5 %). Les intervalles observés entre les traitements et l’oestrus et l’ovulation permettent de préconiser une insémination plus précoce des animaux traités au moyen de progestagènes qu’avec une PGF2α. [less ▲]

Detailed reference viewed: 54 (7 ULg)
Full Text
See detailRégulation de la transcription du virus T-lymphotrope humain de type I (HTLV-1) par le complexe MiniChromosome Maintenance 2-7 (MCM2-7)
Barez, Pierre-Yves ULg

Doctoral thesis (2016)

First oncogenic retrovirus discovered, the human T-lymphotropic virus type 1 (HTLV-1) infects approximately 5 to 10 millions of individuals worldwide. HTLV-1 is the etiological agent of adult T-cell ... [more ▼]

First oncogenic retrovirus discovered, the human T-lymphotropic virus type 1 (HTLV-1) infects approximately 5 to 10 millions of individuals worldwide. HTLV-1 is the etiological agent of adult T-cell leukemia and a neurodegenerative disorder called HAM/TSP (HTLV-1 associated myelopathy/Tropical spastic paraparesis). The HTLV-1 Tax protein interacts with the minichromosome maintenance MCM2-7 helicase, through the amino-terminal part of MCM3. This interaction accelerates firing of late DNA replication origins (ORI) in infected cells. Since Tax acts on the long terminal repeat (LTR), we hypothesized that the MCM2-7 complex could also be recruited to the viral promoter. Using chromatin immunoprecipitation, we show that MCM2-7 indeed interacts with LTR sequences. However, loading of the MCM complex does not fire DNA replication in an autonomous plasmid replication assay. In contrast, MCM2-7 activates viral transcription in luciferase reporter assays and in the context of a proviral clone. Short hairpin RNA interference of MCM2-7 inhibits LTR-driven Tax transactivation in lymphocytes. Finally, siRNAs targeting MCM3 reduce viral transcription in HTLV-1 infected cell lines. Together, our data thus indicate that the presence of the MCM2-7 complex on the HTLV-1 promoter is involved in viral transcription. [less ▲]

Detailed reference viewed: 24 (12 ULg)
Full Text
See detailTherapy of Adult T-cell Leukemia by inhibition of the DNA repair mechanisms
Carpentier, Alexandre ULg

Doctoral thesis (2016)

The Tax oncoprotein plays a central role in viral persistence and pathogenesis of human T-cell leukemia virus type 1 (HTLV-1). Indeed, Tax transforms primary cells and induces tumors in transgenic mouse ... [more ▼]

The Tax oncoprotein plays a central role in viral persistence and pathogenesis of human T-cell leukemia virus type 1 (HTLV-1). Indeed, Tax transforms primary cells and induces tumors in transgenic mouse models. Mechanistically, Tax accelerates the S phase of the cell cycle by firing late replication origins. This modification of the replication timing program induces an oncogenic stress that generates DNA damage such as double-strand breaks. Tax thus provides a selective advantage that promotes proliferation but also exposes host cells to potentially harmful clastogenic damage. How Tax-expressing cells handle this oncogenic stress is currently unknown. In this thesis, we show that Tax-expressing cells activate the DNA Damage Response (DDR). We quantified the repair efficiencies of DNA double-strand breaks. We demonstrate that Tax induces the recruitment of DNA repair core proteins (Ku70, RAD51 and RAD52) on chromatin. We further show that the efficiency of homologous recombination (HR) is inhibited by Tax. In contrast, non-homologous end joining (NHEJ) and single-strand annealing (SSA) are activated in the presence of Tax. Taking advantage of the addiction of Tax-expressing cells on improved DNA repair, we show that pharmacological inhibition of these pathways in HTLV-1 infected lymphocytes leads to an accumulation of DNA damage and apoptosis. We propose a novel therapeutic approach for the treatment of ATL based on the use of inhibitors targeting DNA repair pathways. [less ▲]

Detailed reference viewed: 60 (17 ULg)
Full Text
See detailExpression des propriétés biologiques des substances humiques de lixiviats sur le développement racinaire de ligneux
Tahiri, Abdelghani ULg

Doctoral thesis (2016)

Humic substances (HS) are a dark-colored heterogeneous organic compounds originated from microbial decomposition and chemical degradation of organic matter. The exact structure and composition of HS ... [more ▼]

Humic substances (HS) are a dark-colored heterogeneous organic compounds originated from microbial decomposition and chemical degradation of organic matter. The exact structure and composition of HS macromolecules are not totally elucidated due to their complexity and their structural heterogeneity. They have long been recognized as plant growth promoting substances, particularly with regard to influencing nutrient uptake, root growth and architecture and by improving soil structure. However, the molecular mechanisms through which HS influence plant physiology are not well understood and must be deepened. The aim of this doctoral thesis is to obtain deeper understanding of the biological activity exerted by HS extracted from landfill leachates in comparaison to a commercial formulation extracted from leonardite on roots growth of woody plants in relation to their chemical characterization and mechanisms of action. Three experimental approach have been carried out. The first one concerns a comparative chemical characterization of total HS and derived fractions, separated in function of their solubility and molecular weight, was performed using elemental analysis, UV-vis, FT-IR and 1H NMR spectroscopy and MALDI-TOF mass spectrometry. Obtained results indicate that HS of both origins were basically similar regarding the presence of their chemical structures but, differ mainly in their relative abundance. The second, concerns the development of an in vitro culture model to study the biological activity of HS on the development of root system of two woody pioneer species. The data obtained showed that the effect of HS depends on plant species, concertation, mode of application and source of HS. If the high molecular weight fraction (HA) was effective at promoting root development, the lower ones (FA and OM) inhibit it in function of the concentration used. Finally, a molecular approach was investigated to study some molecular mechanisms that plant act in response to HS comparing the expression of four genes (ABCB1, ABCB19, GS and ADH) implicated respectively in auxin, nitrogen and carbon metabolisms. Obtained data show that HS and their HA fractions influence root growth and development apparently by influencing different mechanism of regulation associated with polar auxin transport, the incorporation of inorganic nitrogen as glutamate, carbon metabolism and abiotic stress responses. Results presented in this thesis showed that landfill leachates HS especially their HA fraction can be valued as bio-stimulant of plant growth. [less ▲]

Detailed reference viewed: 41 (10 ULg)
Full Text
See detailDEVELOPMENT OF PHARMACOLOGICAL TOOLS FOR THE IDENTIFICATION OF G PROTEIN-COUPLED RECEPTORS LIGANDS
Gilissen, Julie ULg

Doctoral thesis (2016)

G protein-coupled receptors (GPCRs) represent the protein family most successfully targeted for treating human diseases. They couple to G proteins to mobilize second messenger pathways that lead to ... [more ▼]

G protein-coupled receptors (GPCRs) represent the protein family most successfully targeted for treating human diseases. They couple to G proteins to mobilize second messenger pathways that lead to cellular responses and ultimately to physiological changes. However many are poorly characterized with few ligands reported or remain completely orphans. Therefore, there is a growing need for screening-compatible and sensitive assays in order to identify new ligands. The present project aims at developing pharmacological tools to characterize the pharmacology and physiology of GPCRs. Our approach rely on i) development of receptor models and assays for the identification of ligands, ii) screening of chemical and virtual small molecules libraries and iii) analysis of structure-activity relationships study of active molecules. The project has been divided in two parts. To set-up assays for the evaluation of GPCRs activation, we selected the understudied succinate receptor 1 (SUCNR1) that is proposed to affect cellular metabolism and pathophysiology of diseases in multiple organs. Nevertheless the receptor has never been validated as a drug target because very few ligands have been described. So, developing pharmacological tools for SUCNR1 remains of great interest in therapeutic drug discovery. First, we have started by examining SUCNR1 signaling pathways in HEK293 cells. Our investigations have highlighted the efficient coupling to Gαi and thus the negative modulation of intracellular cAMP levels. Consequently we have implemented an assay sensitive to cAMP variations to identify ligands able to induce SUCNR1 activation. However, an important drawback to track agonists for Gαi-coupled receptors is the mandatory stimulation of cAMP levels. Inducers such as forskolin must be used and are sources of variations and errors. In order to avoid these artifacts we have set-up and validated a cAMP-inducer free method based on the GloSensor biosensor. This real time assay was amenable to high-throughput screening for the detection of Gαi-coupled receptors agonists. The strategy monitoring basal cAMP levels compared to the stimulated cAMP levels allowed to decrease recording time and artifcats from forskolin use, leading to the identification of fewer false positives and unidentified false negatives. Although both methods found agonists in the chemical library screened, no active new scaffolds on SUCNR1 were discovered. We infer that this method could facilitate the study and screening of Gαi-coupled receptors for active ligands. Secondly, given the interesting potential of SUCNR1 for promising therapeutic advances, we have carried out the study of the receptor interaction with its natural ligand, succinate. We have optimized the previous three-dimensional model for SUCNR1 binding pocket by means of more detailed structure-activity relationships study of succinate related molecules. The study of structure-activity relationships performed by Pierre Geubelle, in parallel to this work, allowed the deduction of the structural elements required to be active on SUCNR1. Thus we have defined a pharmacophore for activity on the receptor and subsequently evaluated various cycloalkanes. With our cAMP assay, Pierre Geubelle has highlighted the (1R, 2S)-1,2-cyclopropanedicarboxylate to be able to activate SUCNR1. We confirmed the activity of this compound on SUCNR1 capacity to recruit arrestin 3 and determined the pharmacological properties of this new ligand as SUCNR1 agonist, in vitro and in vivo. To confirm our in vitro results, we have also assessed the hypertensive properties of this cyclic analogue. Intravenous addition at the dose of 0.1 mg.kg-1 in rats has been demonstrated to increase blood pressure in the same range as succinate. Consequently we have demonstrated that (1R, 2S)-1,2-cyclopropanedicarboxylate could be regarded as an original synthetic full agonist for SUCNR1. In addition, the pharmacophore for SUCNR1 should help to generate synthetic compounds characterized by an increased potency and/or efficacy compared to succinate. [less ▲]

Detailed reference viewed: 93 (3 ULg)