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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 ▲]

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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 ▲]

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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 ▲]

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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 ▲]

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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 ▲]

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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 ▲]

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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 ▲]

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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 ▲]

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See detailẾtude de l’émergence des organisations pastorales et de leur rôle dans les processus de gestion partagée de la vallée de la Tarka dans les départements de Bermo et Dakoro (Centre sud du Niger)
IBRAHIM, Habibou

Doctoral thesis (2016)

Cette thèse vise à analyser les organisations pastorales et leurs rôles dans la gestion des conflits fonciers. En Afrique subsaharienne et particulièrement au Niger, le foncier est au centre des enjeux de ... [more ▼]

Cette thèse vise à analyser les organisations pastorales et leurs rôles dans la gestion des conflits fonciers. En Afrique subsaharienne et particulièrement au Niger, le foncier est au centre des enjeux de l’agro-pastoralisme. La sécurisation des droits d’accès aux ressources et des systèmes de tenure foncière sont essentiels pour la gestion et la résolution des conflits fonciers (Herrea et al., 2007). La région de Maradi constitue la zone de contact entre le Nord pastoral et le Sud agricole. Dans cette partie centrale où la pression foncière, aggravée par la croissance démographique, se pose avec acuité, le spectre des conflits fonciers est malheureusement devenu un phénomène chronique, une donnée permanente (GADO., 2000). La pluralité des normes et plusieurs sources de droit contribuent à complexifier le règlement des litiges fonciers entre acteurs dans les départements de Dakoro et Guidan Roumdji (Moutari., 2001). Or la dynamique globale des systèmes d’élevage est déterminée par la complémentarité des espaces agro-pastoraux. Cette complémentarité est remise en cause par ces pressions foncières et suscite des changements organisationnels dans les communautés du centre Sud du Niger (Yamba., 2004 ; 2000). C’est le rôle des associations pastorales à Dakoro et Bermo qui est l’objet de cette recherche. En effet les organisations paysannes en Afrique Subsaharienne et au Niger en particulier jouent un rôle important dans la définition des politiques agricoles et deviennent des conditions indiscutables de la réussite des actions à promouvoir à l’échelle locale (Courade et Deveze., 2006 ; Mercoiret, 2006 ; Mercoiret et al. 2004). La méthodologie de travail relève de l’approche ethnographique. Les outils et instruments d’enquête sont les questionnaires et les entretiens ouverts avec les acteurs locaux sur les dynamiques territoriales, les modes d’action des associations pastorales et les conflits fonciers. Les résultats viennent aussi des travaux et des documents des projets, des ONG et des rapports des services techniques de l’Etat. Pour un souci de fiabilité des données, nous avons tenu à réaliser des séances de restitution des données et de triangulations pour confronter les informations de diverses sources. Au total 104 personnes sont enquêtées dont 30 % auprès des associations. Ces investigations ont concerné aussi les secrétaires des commissions foncières, les préfets, les agents des projets et des ONG et le président du tribunal de Dakoro ainsi que les leaders pastoraux, les transhumants, les agriculteurs et associations pastorales. [less ▲]

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See detailCaractérisation et tests de traitement des déchets ménagers et boues de vidange par voie anaérobie et compostage pour la ville de Kinshas
Mindele Ukondalemba, Léonard ULg

Doctoral thesis (2016)

Dans les pays en développement (PED) en général et en République Démocratique du Congo en particulier, la problématique de l’assainissement (eaux usées et des déchets solides) constitue un enjeu majeur ... [more ▼]

Dans les pays en développement (PED) en général et en République Démocratique du Congo en particulier, la problématique de l’assainissement (eaux usées et des déchets solides) constitue un enjeu majeur pour les spécialistes et les autorités locales. Cette thèse a comme objectif général de faire une évaluation de l’état des lieux et de dégager des pistes possibles de traitements des déchets solides et liquides en vue de protéger les populations et de s’orienter vers des traitements qui respectent au mieux les principes du développement durable. Pour réaliser cet objectif, il a été question de caractériser les déchets municipaux solides, spécialement des déchets ménagers, par une méthode de caractérisation rapide, simple et peu couteuse. Pour ce qui concerne la gestion des eaux usées, spécialement les boues de vidange provenant de l’assainissement non collectif (ANC), par une méthode sociologique mobilisant des techniques d'enquêtes et d'observation sur site, qui a permis de bien comprendre les pratiques d'assainissement non collectif sur terrain dans le contexte de la République démocratique du Congo ; enfin d’un essai de traitement par une digestion anaérobie (ou co-digestion anaérobie) des déchets suivi du compostage (ou co-compostage).Parmi les modes de traitement de déchets, la digestion anaérobie paraît être une option attrayante pour la dégradation des déchets ménagers fermentescibles en produits utiles tels que le biogaz et le compost de haute qualité. De ce fait, nous avons mené une étude expérimentale comparative entre la digestion anaérobie des déchets ménagers fermentescibles uniquement et la co-digestion anaérobie des déchets ménagers fermentescibles et de boues de vidange de fosse septique. L’expérience a été conduite dans deux cuves de 80 litres. La digestion et la co-digestion anaérobies se sont déroulées à la température de 25°C et en deux étapes, de sorte que la première étape dans la cuve de 80 L, s’arrête à l'acidogenèse et que la deuxième étape se passe dans un autre digesteur de 10 L allant de l’acétogenèse à la méthanogenèse. Les résultats ont montré que 1,3 Nm3 de méthane sont produits à partir de la digestion anaérobie des déchets uniquement et 1,8 Nm3 de méthane sont produits à partir de la co-digestion des déchets et des boues de vidange, confirmant l’intérêt de la co-digestion.Les résultats préliminaires trouvés sont encourageants, notamment en matière de gain detemps dans la durée du processus. Le procédé a entre autres avantages de limiter la manipulation du déchet en cours de traitement et de fournir à la fin deux produits directement valorisables : le compost et le méthane. Bien entendu ces résultats préliminaires devront être validés par des essais à une échelle un peu plus grande avant de proposer de passer à des projets en vraie grandeur. Ainsi nous espérons que ce travail pourra contribuer à la relance des digesteurs anaérobies pour favoriser les énergies renouvelables tels que prôné ce dernier temps par la COP21 et ainsi éviter la déforestation intempestives des nos forets. Mots clés : assainissement non collectif, déchets solides fermentescibles, boue de vidange, co-digestion anaérobie, indicateur d'assainissement, digestion anaérobie, compost. [less ▲]

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See detailEvaluation des charges polluantes (domestiques et industrielles) arrivant au lac Kivu dans la ville de Bukavu, RD. Congo
Lina Aleke, Alex ULg

Doctoral thesis (2016)

Dans les pays en développement (PED) en général, et plus particulièrement en République Démocratique du Congo (RDC), le développement des villes et l'augmentation des populations urbaines se font avec une ... [more ▼]

Dans les pays en développement (PED) en général, et plus particulièrement en République Démocratique du Congo (RDC), le développement des villes et l'augmentation des populations urbaines se font avec une rapidité telle que l'accessibilité à l'eau potable et à l'assainissement de basepose un problème croissant de sante publique et de bien-être des populations. Le manque d'expertise et des moyens techniques et/ou financiers ne permet pas de mettre en place des programmes cohérents et adaptés aux réalités et défis que connaissent ces pays. C'est dans cette optique que la présente étude qui porte sur la caractérisation des eaux résiduaires domestiques et industrielles générées dans la ville de Bukavu, a été menée en vue d'évaluer les flux des pollutions arrivant dans le lac Kivu. Différents axes de recherche ont été ainsi exploités pour répondre a cet objectif. Ce sont :l'évaluation de l'assainissement non collectif (ANC),la caractérisation des flux polluants générés par les activités domestiques et industrielles, etl'analyse critique des atouts naturels (physiques, géologiques, hydrogéologiques, etc.) de la ville de Bukavu en vue de mettre sur pied des filières permettant un assainissement correctet la protection du lac Kivu. L'évaluation de l'assainissement a été basée sur une démarche sociologique faisant appel à des techniques d'enquêtes et d'observation deterrain. Une approche d’évaluation par un indicateur découlant de la combinaison des indicateurs mis en place au prorata des trois maillons composants une filière d’ANC (amont, intermédiaire et aval) a été utilisée. Les résultats obtenus montrent un faible niveau d'accès à l'eau potable et à l'assainissement de base qui serait lié à des facteurs historiques, physiques, politiques, et socio-économiques. De plus, un effort considérable reste à faire pour la gestion du maillon aval car la gestion des boues produites se fait pour le moment de manière non conforme. Par ailleurs, la densité de la population, en pleine croissance, nécessite une politique de construction de logements bien appropriée. Réalisée au niveau des émissaires domestiques (ITFM, Rukumbuka, PIR, Nyamugo et Bagira) et des rivières (Bwindi, Tshula, Wesha et Kahwa) qui traversent Bukavu, la caractérisation des flux de pollutions domestiques a été menéeau travers des méthodes physicochimiques et microbiologiques. Elle a permisd'apprécier l'importance des risques sanitaires qu'encourent les habitants de Bukavu dans leur quotidien, ainsi que l'ampleur des pressions que subit le lac qui en est le réceptacle. De la même manière, notre étude s'est intéressée aux flux produits des pollutions industrielles brassicoles et pharmaceutiques, suivant une approche physicochimique. Il ressort de ces analyses que les émissaires domestiques constituent le cadre de premier choix adopté par les habitants pour le rejet de leurs déchets. Ce faisant, les rivières de la ville font l'objet d'importantes pollutions engendrées par les activités domestiques, et constituent des égouts à ciel ouvert. Les flux évacués et arrivant quotidiennement dans le lac vont de 2165 kg (rivière Bwindi) à 5974 kg DBO5 (riviere Kahwa) en saison sèche, et de 5303 kg (rivière Bwindi) à 14270 kgDBO5 (rivière Kahwa) en saison de pluie, correspondant aux charges totales respectives de 7468 kg DBO5 et 20244 kg DBO5. Les flux des pollutions microbiologiques ont été évalués a 2,3.109 UFC/EH DBO5 pour la rivière Bwindi et 6.109 UFC/EH DBO5 pour la rivière Kahwa en ce qui concerne les coliformes fécaux, et 2800 œufs/EH DBO5 (rivière Bwindi) et 4185 œufs/EH DBO5 (rivièreKahwa) pour les parasites.En outre, 11 taxons de parasites ont été identifiés. Ce sont : Entamoeba coli, Giardia lamblia, Entamoeba histolytica, Ascaris sp. (taxon le plus distribué), Ankylostoma sp., Strongyloides sp., Trichuris trichiura, Hymenolepis nana, Hymenolepis diminuta, Taenia saginata et Schistosoma mansoni. Recevant les eaux de 4 de 5 émissaires domestiques étudiés, la rivière Kahwa s'est avérée comme la plus polluée des rivières de Bukavu. Concernant les pollutions industrielles, pour chaque litre de boisson (bières et boissons gazeuses confondues), la société brassicole Bralima utilise entre 4,7 et 5,7 l d'eau, avec une moyenne de 5,1 l.Les pollutions spécifiques s'établissent entre 1,2 et 1,6 kg DCO/hl, et 0,2 et 0,4 kg MES/hl de produits finis, avec unecharge globale évaluée 194,1 kgDCO par jour, avant traitement. L'abattement des pollutions dans la station d'épuration de cette société brassicole devrait être amélioré en vue de réduire ses pressions sur le lac et les risques sanitaires auxquels sont exposées les populations. Quant à la Pharmakina, la charge globale des pollutions, évaluée à 1229,2 kgDCO par jour, arrive dans le lac Kivu sans aucun traitement préalable, constituant ainsi de graves menaces environnementales et écologiques imputables à sa responsabilité. [less ▲]

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See detailPrincipal static wind loads within a rigorous methodology to the envelope reconstruction problem
Blaise, Nicolas ULg

Doctoral thesis (2016)

Static wind loads are being used for the design of large civil structures such as high-rise buildings, large roofs and long-span bridges. Once static wind loads are known, they are used through the ... [more ▼]

Static wind loads are being used for the design of large civil structures such as high-rise buildings, large roofs and long-span bridges. Once static wind loads are known, they are used through the iterative design process without repeating cumbersome dynamical analyses. In this framework, structural engineers can effectively focus on the structural sizing since static analyses are straightforward. No codified wind loads, however, exist for those large structures with unique shapes and there is no consensual view on how to formally derived them. For each new major project, the challenge consists therefore in deriving a relevant set of static wind loads. Obviously, these loads must provide the actual envelope values of structural responses of interest. This states the objective of the envelope reconstruction problem and constitutes the core of this thesis. The proposed developments to solve this problem are relevant for structures responding with a linear dynamic behavior to the buffeting action of synoptic winds in a stationary framework. The pioneering concept of Equivalent Static Wind Load is normally considered for the design. An extensive review points out two main limitations of the current formulations. They have been originally established in a Gaussian context, are associated with either a nodal or nodal-modal basis and do not have a formal definition. The proposed Conditional Expected Load method overcomes the three drawbacks by defining a Conditional Expected Static Wind Load. This novel approach presents a general rigorous formulation for linear structural behavior, irrespective of the basis used for the analysis and relevant in a non-Gaussian context. The method is particularized for a certain class of non-Gaussian processes through a bicubic translation model. This model covers a large range of non-Gaussianity in the random processes and therefore paves the way for the formal establishment of “non-Gaussian” static wind loads with a physical interpretation. Other kinds of static loads such as the covariance proper transformation loading modes and the modal inertial loads are additionally studied. Unfortunately, both sets of loads are simply relevant for two limit structural behaviors, quasi-static and resonant, respectively. Moreover, they do not adapt to the set of structural responses of interest. From both points of view, one key result from our study is the innovative concept of Principal Static Wind Load as a sound solution for the envelope reconstruction problem. The concept relies upon a robust mathematical foundation. These loads are determined by the singular value decomposition of a large set of equivalent static wind loads. This decomposition can be seen as a way to rank the most relevant load patterns for the envelope reconstruction problem. The principal static wind loads have also the added distinctive advantage to be flexible. They are, indeed, able to naturally adapt to the set of structural responses of interest. Finally, a complete methodology to solve the envelope reconstruction problem irrespective of the structure, its load-bearing system and its susceptibility to vibrations in a Gaussian or non-Gaussian context is rigorously conceptualized. The intrinsic controllability of a set of pertinent parameters provides a smart balance between over and underestimation of the actual envelope. Moreover, combinations of static wind loads are computed to speed-up the reconstruction of the envelope values. The problem of determining these combination coefficients is formulated as a constrained nonlinear optimization. Equivalent and principal static wind loads, covariance proper transformation loading modes and modal inertial loads are implemented within the proposed methodology. Three examples: a four-span bridge, a real-life large stadium roof and a low-rise building demonstrate that the envelope reconstruction accuracy is considerably improved with principal static wind loads and with combinations thereof. [less ▲]

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See detailPerturbations of interactome networks in acute lymphoblastic leukaemia: identification of EXT1 tumor suppressor as a Notch pathway regulator
Daakour, Sarah ULg

Doctoral thesis (2016)

Whole genome sequencing technologies have enabled the identification of mutations implicated in diseases including cancer. Recently, research efforts to compare and categorize mutations, genes expression ... [more ▼]

Whole genome sequencing technologies have enabled the identification of mutations implicated in diseases including cancer. Recently, research efforts to compare and categorize mutations, genes expression and genomic characteristics helped generating literature-curation databases. A large number of databases were developed to address data integration and standardization for human cancers, such as Catalogue Of Somatic Mutations In Cancer (COSMIC), The Cancer Genome Atlas (TCGA), International Cancer Genome Consortium, Integrative Onco Genomics (IntOGen). Although the identification of these mutations highlights “cancer causative genes”, it does not give a detailed explanation of molecular mechanisms leading to the development of cancer. Though, understanding mechanisms leading to cancer development and progression remains a challenge that requires further investigations. The great majority of mutated genes are found in liquid tumors such as leukemia and lymphomas. In the first part of this study, we reasoned that leukemia associated genes could be extended to additional candidates identified using interactomic approaches. We used protein-protein interaction (PPI) mapping strategies to explore information on cancer genes frequently mutated in Acute lymphoblastic leukemia (ALL). We first extracted mutational data associated to ALL, and used interactome mapping analysis for literature-curated interactions and yeast two-hybrid experimental data in order to identify potential novel target genes associated with ALL. We highlighted mutated hub proteins interconnected in an ALL-cancer gene products network and identified novel interacting partners that link key ALL-cancer driver gene products. We identified EXT1 tumor suppressor gene as a novel common interactor for NOTCH1 and FBXW7. In the second part of this study, we experimentally validated EXT1, as a novel player in the regulation of the Notch pathway. Our study thus provides a proof-of-concept on how systematic interactome approaches could allow identification of novel targeted genes and pathways associated to human cancer. [less ▲]

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See detailEpidemiological Study of Canine Leishmaniasis in Algeria and its Impact on the Human Visceral Leishmaniasis
Adel, Amal ULg

Doctoral thesis (2016)

Zoonotic visceral leishmaniasis (VL), caused by Leishmania infantum is a vector-borne disease, transmitted to humans by the bite of infected female phlebotomine sand flies. In absence of treatment the ... [more ▼]

Zoonotic visceral leishmaniasis (VL), caused by Leishmania infantum is a vector-borne disease, transmitted to humans by the bite of infected female phlebotomine sand flies. In absence of treatment the outcome is death. The disease is characterised by irregular fever bouts, loss of weight, hepatosplenomegaly and anaemia. It is endemic in the Indian sub-continent and in East Africa. In the Mediterranean region, it is present in rural areas, in villages, in mountain areas, but also in certain peri-urban zones, where the parasites survive in dogs and other mammals. In fact, domestic dogs are the principal reservoir of human VL and they also can develop a more generalised and fatal form of the disease, although more than half of the dogs remain asymptomatic, the individual outcome depending on both cellular and humoral immune responses. Both symptomatic and asymptomatic dogs can infect the phlebotomine vectors, thereby enabling the transmission to other dogs or to people. This is the main reason why early detection and treatment of infected animals is the best way to reduce the risk of infection and, as such, forms an essential component in the prevention and control of the human disease. Ideally, a so-called “gold standard” test is required to reliably and correctly determine the infectious status of an individual and/or the infection prevalence in a population in a certain region at a certain point in time. A gold-standard test provides an error-free classification of individuals as infected or infection-free. The discriminative power of a real-life test is quantified by measures of precision, more specifically the sensitivity and the specificity of the test. They vary in function of characteristics of the population studied. In the majority of cases, a gold standard test does not exist. In order to overcome this lack, use is made of reference tests. The latter are often imperfect (sensitivity and specificity below one) and they allow estimation of a so-called apparent prevalence rather than the actual true prevalence. A statistical solution to the problem of lack of gold standard test consists of a Bayesian approach, which allows us to combine data of a study with external (prior, independent) information, such as results from previous studies or expert opinion. This approach yields an estimate of the true prevalence, as well as estimates of the sensitivity and specificity of the tests used. This thesis attempts to contribute towards a better understanding of the epidemiology of visceral leishmaniasis in Algeria. More specifically, our general objective (Chapter 3) was to estimate the true prevalence of canine leishmaniasis, in a situation where a diagnostic gold standard test was unavailable, and to describe the epidemiological curve and profile of visceral leishmaniasis in the country. With this in mind, the work is organised in nine chapters. The first chapter outlines the importance of leishmaniasis (respectively visceral and canine) in terms of public health and veterinary public health and provides an overview of the current knowledge base on canine leishmaniasis. The second chapter is devoted to a description of the epidemiological methodology available for the estimation of the true prevalence and the test characteristics in the absence of gold standard test. Chapter 4 describes an epidemiological study conducted in the capital city Algiers, comprising 462 dogs subdivided in four groups according to their function (stray dogs, guard dogs, farm dogs and pet dogs). A Bayesian approach was used to estimate the true prevalence of canine leishmaniasis in the four groups and to evaluate three serological tests: an indirect immunofluorescence test (IFAT), a direct agglutination test (DAT) and a commercial rapid test on gel, based on the protein rK39 (PaGIA). We were able to demonstrate variability in the test performance characteristics in the different groups, and this in terms of sensitivity and specificity. IFAT, although it is an imperfect test, is nevertheless the test of choice when the dog population targeted consists of stray dogs, but its specificity drops to a unsatisfactory 65.2% (IC: 60.2-73.5%) when applied to farm dogs: the fact of living together with other animals may induce cross-reactions. Stray dogs also yielded the highest estimate for the true prevalence (11.7%), probably a consequence of their constant living outside, which increases the risk of exposure to infected phlebotomine vectors. Using the above results, a large-scale transversal survey was mounted in six towns of the littoral zone of Algeria (Chapter 5). Thus, a total of 2,184 farm dogs and guard dogs were sampled in two distinct periods using two serological tests: before and after the main vector season, using IFAT and DAT. Serial and parallel interpretation of the combined tests were compared to various other statistical methods in order to estimate the true prevalence and the sensitivity and specificity of the two tests. The latent class model of Hui and Walter based on conditional independence between the diagnostic tests was compared to a Bayesian model, which made it possible to include conditional dependency between tests, if required. The best-adjusted model estimated canine leishmaniasis prevalence between 11% and 38% with an increasing trend from west to east. IFAT sensitivity varied between 86% and 88% in the different localities, whereas specificity ranged between 65% and 87%. DAT was invariably less sensitive than IFAT, but had a better specificity: between 80% and 95% in function of locality and season. The results highlighted once more the danger of considering IFAT to be a gold standard test for canine leishmaniasis. Chapter 6 draws up an epidemiological profile of human zoonotic visceral leishmaniasis in Algeria, based on cases notified to the National Public Health Institute between 1998 and 2008. A total of 1,562 were found for this period. This translates into an incidence rate of 0.45 cases per 100,000 inhabitants, of which 81.4% were children between zero and four years of age. Splenomegaly, fever, pallor and pancytopenia were the principal clinical and biochemical signs. Antimonies are the first-line treatment drugs in paediatric wards and amphotericin B injections are the treatment of choice in adults. Severe under-declaration (less than one case in ten notified) was demonstrated thanks to a survey carried out in the paediatric, internal medicine and infectious diseases departments of the five university hospital centres in Algiers, which had an influx of patients from all four corners of the country. Results of both Chapter 5 and Chapter 6 revealed a concordance between human visceral leishmaniasis incidence rates and true prevalence of canine leishmaniasis, providing extra support for the hypothesis that dogs are the main reservoir of the disease. Motivated by the results of the two surveys (Chapters 4 and 5), Chapter 7 describes a literature review of the performance of IFAT when used to estimate the canine leishmaniasis prevalence in the Mediterranean basin. Chapters 8 and 9 present the general discussion and conclusions and recommendations of the overall contribution of this research effort. Even though this work only represent a small addition to knowledge body on visceral leishmaniasis, it allowed us to better describe and understand the epidemiology of visceral leishmaniasis in Algeria and to obtain true prevalence estimates of canine leishmaniasis in various towns in the littoral zone of the country. It showed us the importance of correctly identifying and defining the target population of surveys to obtain the best possible posterior estimates and to optimise control measures. This work also showed the efficacy of the application of appropriate statistical models in a Bayesian framework when confronted with the absence of a gold standard test. Chapter 10 summarizes all references cited in the thesis. [less ▲]

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See detailFlexibility services in the electrical system
Mathieu, Sébastien ULg

Doctoral thesis (2016)

The work presented in this thesis considers the electrical flexibility from the electric load to its usage as a commodity. The conception of the European electrical system has led to a large amount of ... [more ▼]

The work presented in this thesis considers the electrical flexibility from the electric load to its usage as a commodity. The conception of the European electrical system has led to a large amount of actors that are impacted by flexibility exchanges. This thesis proposes approaches to assess the impact of exchanging flexibility in the electrical system and analyzes the complex interactions resulting from these exchanges. The modeling techniques used to carry the analysis are optimization, game theory and agent-based modeling. The impacts on different parts of the electrical system are presented: the day-ahead energy market, the secondary reserve and the distribution system. Since flexibility is the base block of this thesis, two methods to obtain flexibility from actual consumption processes are broached: direct control of the loads and dynamic pricing. One chapter provides an example of how flexibility can be obtained by the direct control of a portfolio of heat pumps and another chapter studies the control of electric heaters and boilers via the use of a simple price signal. [less ▲]

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See detailStratégies innovantes d’adaptation à la variabilité et au changement climatiques au Sahel : cas de l’irrigation de complément et de l’information climatique dans les exploitations agricoles du Burkina Faso
Zongo, Bétéo ULg

Doctoral thesis (2016)

The Sahelian farmers, the scientific community, government and development partners are actively looking for new farming practices to mitigate the consequences of dry spells probably exacerbated by ... [more ▼]

The Sahelian farmers, the scientific community, government and development partners are actively looking for new farming practices to mitigate the consequences of dry spells probably exacerbated by climate changes. To contribute for this challenge, this research examines the issue of agricultural innovations’ adoption in the Sahelian and Sudano-Sahelian zones of Burkina Faso. Among promoting agricultural innovation, the study explored the possibilities to popularize the practice of supplemental irrigation from individual basins (ICBI) and the use of climate information (CI) in the farms. The approach developed is threefold. Data were collected from farm households through surveys and conducting experimentation of ICBI and use of CI in rainfed agriculture. In addition to the usual descriptive statistics, analysis of variance, the multinomial logit model was used to analyze the determinants of the agricultural innovations dissemination. Determining factors of farmers’ willingness to adopt ICBI were identified using a logistic model. The criteria for partial budgeting were used as tools for assessing the economic viability of ICBI. The Heckman model associated with the contingent valuation approach was used to analyze famers’ willingness to use CI. Simulations were made from a bio-economic model to test some policy instruments for the adoption of these new practices. After four decades of diffusion (1974-2013), the adoption rate is estimated at 69.3% for stone bunds, 49.1% for zaï, 26.2% for grass strips and less than 10% for half-moons, bunds land and mulching. The low level of farmers’ organization and access to agricultural services were the major constraints to their adoption. Over 65% of the farmers believe that ICBI is an effective way to mitigate the adverse effects of dry spells on crop yields. After three years, the experiments showed that this innovation in family farms increases maize yield by 1.08T/ha (88.3%). Maize production surplus achieved with ICBI can fill the monthly cereal requirements of 17 people on average and increases the gross margin by F 178,483 CFA compared to the situation without irrigation. The review of the net present value, internal rate of return and the net benefits increase ratio showed that the profitability to practice supplemental irrigation depends on the types of basins. From the sampled farmers, 93% of them required CI to guide their decision in planning agricultural activities. About 64% of the farmers are willing to pay for CI. The experiments reveal that the surplus of maize and sorghum yield obtained with the use of CI meets the monthly cereal requirement of 7 persons on average compared to traditional seasonal forecasts. The simulations indicate that the ICBI in middle year increases the expected income of 26.5% (F 133 030 CFA) compared to the situation without irrigation. The tested policies include six types of grant and the establishment of a system for granting credit to farm households to finance the supplementary irrigation device. The implementation of these policies should facilitate the adoption of ICBI at a larger scale. The researchers and development actors should pursue the experimentation on the combination of ICBI and CI. [less ▲]

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See detailIndirect quadrangular mesh generation and validation of curved finite elements
Johnen, Amaury ULg

Doctoral thesis (2016)

Among the different types of 3D finite element meshes, hexahedral meshes present properties that can be highly desirable, such as alignment with physical features or a lower computational cost. For this ... [more ▼]

Among the different types of 3D finite element meshes, hexahedral meshes present properties that can be highly desirable, such as alignment with physical features or a lower computational cost. For this reason and despite the maturity of the tetrahedral mesh generators, hexahedral mesh generation has always been a prolific research domain. Yet, there exists currently no robust algorithm capable of generating conformal all-hexahedral meshes with prescribed input size field on any arbitrary geometry. One difficulty that remains is that there exists no method to robustly assert that a hexahedron is valid. Indeed, linear hexahedra can be folded (tangled) in the same way than curvilinear tetrahedra. This thesis addresses two subjects. First, two original quadrangular mesh generation techniques are investigated, with the aim to generalize them to 3D. Both are indirect methods and thus consider the problem of combining pairs of triangles of an initial input triangular mesh. The first technique, called Blossom-Quad, computes the optimal solution of this problem with respect to a given quality criterion. As for any indirect method, the quality of the solution strongly depends on the location of the nodes in the initial triangular mesh. The generalization to 3D is however unclear and a second technique is investigated. This one aims at computing a near-optimal solution by using a look-ahead tree technique. The corresponding algorithm allows tuning the quality of the final mesh by choosing the depth of the tree as a parameter. This technique gives a promising way forward, especially as it is directly applicable in 3D. The second subject concerns the development of a method that permits to compute, with respect to any prescribed tolerance, the extrema of Jacobian-based quantities defined on finite elements of any order and type. Applied to the Jacobian determinant, this method allows to assert the validity of any (curvi-)linear finite element. This method is also applied to a quality measure that quantifies the pointwise anisotropy of the elements. Besides being very attractive for hexahedral mesh generation, this method is especially useful for the analysis of curvilinear finite element meshes. It can moreover be an important component of optimization techniques for achieving robustness. [less ▲]

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See detailMultiscale approach of spray retention on superhydrophobic plant surfaces
Massinon, Mathieu ULg

Doctoral thesis (2016)

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See detailLower Carboniferous shallow marine sequences from the Central Alborz Basin, Iran (north-eastern margin of Gondwana): sedimentology, biostratigraphy and rock– magnetic studies
Sardar Abadi, Mehrdad ULg

Doctoral thesis (2016)

The Lower Carboniferous Mobarak Formation records the development of a carbonate platform on the southern Paleo-Tethyan passive margin. This pervasive carbonate factory was deposited following the opening ... [more ▼]

The Lower Carboniferous Mobarak Formation records the development of a carbonate platform on the southern Paleo-Tethyan passive margin. This pervasive carbonate factory was deposited following the opening of the Paleo-Tethys Ocean into the Alborz Basin along the northern margin of Gondwana. The depositional facies range from the most proximal to the most distal and include coastal environments, inner ramp peritidal facies, peloidal to crinoidal shoals, storm to fair-weather influenced mid-ramps, proximal to distal shell beds and low energy outer ramps. Storms clearly played a dominant role in the distribution of skeletal and non-skeletal shoals on the carbonate ramp. Sedimentological analyses complemented with foraminiferal biostratigraphy reveal four events which are interpreted to represent the principal factors controlling carbonate platform evolution in the Alborz Basin during the Lower Carboniferous: 1) A transgression linked to global temperature rise in the Early Tournaisian (Middle Hastarain) resulted in the formation of thick-bedded argillaceous limestones. 2) the Hastarian–Ivorian boundary glaciation phase, 3) Upper Ivorian–Lower Viséan? tectonic block faulting. 4) the Viséan- Serpukhovian glaciation phase. The three foraminiferal assemblages encountered in the Tournaisian interval of the Mobarak Formation are restricted to specific periods within the Ivorian. The occurrence of specific foraminiferal taxa in Alborz is tightly governed by transgressions and migration of North Paleo–Tethyan biotic elements as response to the thermal period. We also combined proxies for ambient paleothermometry in addition to the indications for arid conditions and arid conditions and the presence of foraminiferal taxa with a North Paleo-Tethyan affinity in the Lower Carboniferous Mobarak Formation to suggest a paleo-position for the Alborz Basin at lower latitudes than approximately 45  –50  southern paleolatitude reported thus far. Magnetic susceptibility ( in ) was measured and compared with facies from the same sample. There is a clear link between  in and facies, and the average  in values are higher for distal facies than for proximal ones. The  in profile of Lower Carboniferous carbonate sequence reflects stratigraphic variations in response to relative sea level changes and detrital input. In the context of the sequence stratigraphic framework, the average  in values for lowstand and transgressive system tracts deposits are higher than for the highstand system tracts deposits. The clear link between  in and facies points to at least partly preserved primary  in signal, related to detrital inputs. In respect to the hysteresis measurements the in signal is mainly carried by low coercivity ferromagnetic minerals such as magnetite, with a mixture of relatively coarse grains (detrital fraction) and ultra-fine grains (probably formed during diagenesis). [less ▲]

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See detailCoating of crystallized Yttrium Orthoferrite (o-YFeO3) by wet deposition methods
Stevens, Frédéric ULg

Doctoral thesis (2016)

L’objectif de cette thèse est d’obtenir un dépôt d’orthoferrite d’yttrium orthorhombique sur substrat conducteur. Ceci, en vue de d’étudier de nouveaux catalyseurs potentiels pour le clivage ... [more ▼]

L’objectif de cette thèse est d’obtenir un dépôt d’orthoferrite d’yttrium orthorhombique sur substrat conducteur. Ceci, en vue de d’étudier de nouveaux catalyseurs potentiels pour le clivage photoélectrochimique de l’eau. Le clivage photoélectrochomique de l’eau produit dudihydrogène et du dioxygène grâce à l’énergie solaire et un catalyseur. Le dihydrogène et le dioxygène sont les combustibles d’une réaction exothermique. Transformer l’eau en ces deux composés est donc une méthode de stockage de l’énergie. Plusieurs semiconducteurs sont étudiés comme catalyseurs pour ce clivage. Cette thèse se concentre sur l’étude de l’un d’eux : l’orthoferrite d’yttrium orthorhombique (o-YFeO3), et sur deux méthodes de dépôt de ce matériau sur substrat conducteur : la méthode de déposition par plongée (dip-coating) et la pyrolyse d’une vaporisation ultrasoniquement générée (USP). Dans un premier temps, deux méthodes de synthèse del’o-YFeO3, sous forme de poudre, ont été envisagées : l’une basée sur des chlorures de fer et d’yttrium, l’autre basée sur les nitrates de ces mêmes métaux. Les éventuels problèmes de proportion ou de précipitations successives ont été respectivement dissipés par une étude de masse et une analyse de l’évolution du pH. Ces poudres, issues des chlorures ou des nitrates, ont permis de caractériser la proportion et la pureté des phases cristallines en fonction de la température de calcination par l’étude de la diffraction des rayons X (XRD) ; de caractériser l’énergie de la bande interdite (band gap optique) par la spectroscopie de réflectance diffuse (DRS) et d’en observer leur morphologie par les microscopies électroniques à balayage (SEM) ou en transmission (TEM). Toutes ces analyses nous ont poussés à continuer notre étude en nous focalisant sur la synthèse basée sur les nitrates et d’utiliser une température de calcination de 850°C. Ensuite, ces mêmes analyses (pH, XRD, DRS) ont permis d’estimer l’influence de l’ajout de différents composés organiques en cours de synthèsesur la cristallinité, la pureté, la température de calcination et l’énergie de la bande interdite de ces poudres. Cette thèse a montré que l’additif qui améliore au maximum ces propriétés est l’acide citrique. Dans le cas des poudres, dès 450°C – soit 400°C de moins que la même synthèse sans acide citrique – l’o-YFeO3est cristallisé. Les solutions qui seront utilisées pour les méthodes dedéposition seront donc composées à partir, entre autre, de nitrate de fer, de nitrate d’yttrium et d’acide citrique. La méthode dite du « dip-coating » consiste à plonger le substrat qu’on compte recouvrir dans une solution de précurseurs – composée, entre autre, des nitrates métalliques et d’acide citrique – de le ressortir recouvert d’un film mince de cette solution pour ensuite le chauffer et ainsi obtenir un dépôt du matériau désiré. De nombreux problèmes d’adhérence, de stabilité de solution, de quantité de matière, d’homogénéité de dépôt et de cristallisation de composé ont eu raison de nos efforts pour la mise au point de tels dépôts par cette technique. L’autre méthode de déposition utilisée durant cettethèse est l’«USP ». Cette technique vaporise une solution de précurseurs au moyen de vibrations ultrasoniques. Le brouillard ainsi généré est propulsé vers le substrat par du gaz sous pression. Le substrat, pendant ce processus, est placé sur une plaque chauffante. La solution vaporisée chauffera au fur et à mesure qu’elle se rapprochera du substrat. Cette technique implique l’ajustement de plusieurs paramètres qui définissent le type de composés qui atteindront le substrat. Cette thèse a abouti à la mise au point de ces différents paramètres qui ont permis d’obtenir un dépôt d’orthoferrite d’yttrium orthorhombique sur un substrat conducteur. Ce dépôt présente une activité photoélectrochimique en tant qu’anode pour le clivage de l’eau, mais ses performances ne permettent pas, dans son état actuel, de concurrencer les semiconducteurs précédement décrit par d’autres chercheurs. Une poursuite des travaux dans ce domaine devraient se focaliser sur le dopage et/ou la structuration contrôlée de l’orthoferrite d’yttrium. [less ▲]

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See detailContribution à l'amélioration de la production laitière et de la reproduction des vaches Ankole et croisées Ankole x Frisonne en territoire de Beni, République Démocratique du Congo
Katungu Kibwana, Denise ULg

Doctoral thesis (2016)

Eastern Democratic Republic of the Congo, especially Kivu, is a large pastoral region but the cattle numbers of which considerably decreased following the conflicts that the country underwent over the ... [more ▼]

Eastern Democratic Republic of the Congo, especially Kivu, is a large pastoral region but the cattle numbers of which considerably decreased following the conflicts that the country underwent over the past two decades, with important losses in breeding skills. Cattle breeding currently practiced in Kivu may be described as "great unknown". Data available in literature relate to old studies and focuse on peripheral areas from Kivu. This study aimed, at first, to establish a diagnosis on dairy cattle breeding inhabits in the east of the Democratic Republic of the Congo, especially in the provinces of North Kivu. This diagnosis based on the choices adopted by breeders according to animal genetic, constraints related to feeding, animal housing and the main reproductive characteristics of females. The other objective of the study was to test an improved farming method taking into account the perceived constraints highlighted with the diagnostic investigation. The proposal took into account the realities of the south, and thus was characterized by simplicity and speed of implementation, in the emergency context that the population lives daily in the region. 1. Breeding cattle and milk production in tropical environments: Case of eastern region of the Democratic Republic of the Congo. Inventory and perspectives. In East of Democratic Republic of the Congo, cattle breeding is based on exploitation of non-selected dairy cattle raised in extensive unimproved rearing system. Extensive breeding of traditional type is the bulk of the pastoral activities in the region and the country. The main factors limiting cattle breeding in this area of D.R. of the Congo, as in most tropical environments, consist in: (i) low genetic potential of African cattle with low level of production and (ii) poor farming conditions due to low feed quality and health coverage, precarious livestock housing, poor management of reproduction and animal genetic resources, and low breeders’ technicity. These factors affect productive and reproductive performance of animals. Low milk production arising does not allow breeders to provide their needs and cover milk needs of the population, thus leading to importation of large amounts of milk and its derived products. 2. Extensive farming practices and cattle performances of the local breed and crossed with exotic dairy breeds in the Democratic Republic of the Congo The study was conducted in Beni, Democratic Republic of the Congo. It aimed to highlight the breeding cattle system and dairy production levels of both local cows and cows crossed with exotic dairy breeds raised in the environment, and reproductive parameters (age at first calving, interval calving and fertility) as well as mortality rate of animals. The data, obtained from 8464 animals, including 4805 cows (2309 local vs 2496 crossed with Sahiwal and exotic dairy breeds - Friesian, Brown Swiss and Jersey considered ameliorative) were analyzed by chi-square test for categorical data, by generalized linear model based on the genetic type, forage quality and type of supplementation for continuous data, and by Anova-One-way for to test the effect of the degree of specialization and professionalism of breeders. Non-parametric data were analyzed by Spearman correlation test. All factors studied had a significant influence on milk production (P <0.001); calving interval, meanwhile, was significantly influenced by breed (P <0.002) and the type of supplementation (P= 0.011), age at first calving was only influenced by the breed (P <0.001). Milk production, age at first calving, calving interval, fecundity rate and mortality rates of local cattle were respectively 2.6 ± 0.17 l/d, 41.1 ± 1.02 mo, 22.6 ± 0.73 mo, 53.0% and 4.8% between 0 and 1 year and 3.6% between 1 and 2 years vs 6.1 ± 0.21 l/d, 32.5 ± 1.21 mo, 19.1 ± 0.87 mo, 44.8%, 6.7% between 0 and 1 year and 4.4% between 1 and 2 years, respectively, in crossed type. Forage supplementation had a significant effect on milk production compared to the situation with natural forage (1.6 l/d more, P <0.001), and by-products supplementation associated or not to mineral permitted an increase of 0.9 liter of milk production compared to the situation without supplementation (P= 0.041). Increased supplementation with or without the mineral reduced calving interval by 3.6 mo compared to the situation without supplementation, and by 2.5 mo compared to the simple supplementation (P= 0.011). The type of forage had no significant effect on calving interval. The mortality rate was significantly influenced by breed (P= 0.017). A significant interaction between the genetic type and forage type was observed on milk production (P <0.001). Some parameters studied were also influenced by degree of specialization of the breeders - calving interval (P= 0.04 in crossbred type and P <0.001 in local bred) - age of first calving in local bred (P= 0.015); and by degree of professionalization - age of first calving in local bred (P= 0.04) - calving interval (P= 0.08) and milk production in crossbred type (P= 0.04). 3. Effect of improved feeding and housing, and of Friesian blood level on milk production of Ankole x Friesian crossbred cows The study was carried out at the Vitolu/Misugho farm extension, in Beni territory, Democratic Republic of Congo. The objective of this study was to quantify the effects of rearing conditions (feeding and housing in stall of night), and of Friesian blood level on milk production of Ankole x Friesian crossbreds cows. Data were obtained from 30 cows. The birth weights of calves were compared between groups using a Student test. Using the SAS software (Statistical Analysis System, version 9.1.3), data on average daily milk production were analyzed using a mixed model (proc mixed), including the effects of treatment group, Friesian blood level, day in milk, and the simple interactions between these effects. Day in milk within animal was included as a repeated measurement, and a type 1 autoregressive covariance structure was associated to. Differences were considered significant at P <0.05. The indicators of variation were expressed as standard deviation. The experimental unit was the cow. All factors affected significantly daily milk production (P <0.001). The results of these analyzes show that average milk production was higher group offered the improved feed and housed in the stable (6.8 ± 0.31 l/d vs 5.2 ± 0.31 l/d in the control group cows housed in kraal at night, P <0.001). The pic of milk production was observed around the 79th and 96th days respectively in IG and CoG. In both groups, cows adapted their milk production for the rainfall regime and milk production was significantly higher during the rainy season. Lactation curve was very dependent on rainfall regime and did not follow the shape of a normal curve. Improved milk production and highest values were observed with >25% of Friesian blood level (5.3 ± 0.31 l/d to 6.6 ± 0.23 l/d, from 25 to 44%, P <0.001). Interactions between treatment (improved feed and housing) and Friesian blood level were also observed (P <0.001). The IG cows showed the highest milk production compared to the control group (milk productions of 5.8 ± 0.50; 7.0 ± 0.66 and 7.8 ± 0.70 l/d were obtained with 25, 38 and 44% of blood Friesian, respectively, in the treated group vs. 4.8 ± 0.23; 5.5 ± 0.23 and 5.4 ± 0.16 l/d in the control group, P <0.001). [less ▲]

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See detailRankine cycle based waste heat recovery system applied to heavy duty vehicles: topological optimization and model based control
Grelet, Vincent ULg

Doctoral thesis (2016)

standards force the original engine manufacturers to search for innovative solutions in order to reduce oil consumption. As an important part of the energy contained in the primary carrier (the fuel) is ... [more ▼]

standards force the original engine manufacturers to search for innovative solutions in order to reduce oil consumption. As an important part of the energy contained in the primary carrier (the fuel) is lost to the ambient through heat, it seems convenient to recover a part of this thermal energy and to turn it into fuel consumption reduction. Thermodynamic bottoming cycle such as the Rankine cycle could be used to meet this objective. Its popular use throughout the world for electricity generation makes it a natural candidate for on-board implementation in vehicles. However, a certain number of hurdles are still present before the system can be efficiently applied to heavy-duty trucks. In the last thirty years, numerous studies heave been carried out to evaluate the real potential of that kind of system on a vehicle but nothing has yet been commercialized. The heat sources to recover from, the constraints relative to the on-board application and the long and frequent transient behavior of the vehicle mean both the system architecture and its control strategy need to be optimized. The system optimization leads to a choice in terms of working fluid, heat sources and sinks, and components sizing in order to maximize power recovery and hence the fuel saving. The control plays a major role by using the capability of such a system to ensure an efficient and safe operation and limiting the interactions with the other vehicle sub-systems. In this thesis, a system design methodology is introduced to optimize the system architecture using complete model-based vehicle simulation. The constraints relative to the mobile application are taken into consideration to evaluate the potential of such a system. Modelbased control strategies for on controlled variable, namely the superheat level, are developed. Constrained by the implementation platform, different control frameworks ranging from PID to model predictive controllers or observer based controllers are developed to fit into a normal automotive electronic control unit. Most of these novel strategies were experimentally validated on a test rig developed during the thesis. [less ▲]

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See detailDynamique des flux de carbone entre l'atmosphère et des écosystèmes ouest-africains: cas des forêts et savanes sous climat soudanien au Bénin
Ago, Expédit Evariste ULg

Doctoral thesis (2016)

In West Africa as elsewhere in other parts of the world, natural and anthropogenic ecosystems are the main sources for energy, building poles and livestock fodder. They probably behave like some nets ... [more ▼]

In West Africa as elsewhere in other parts of the world, natural and anthropogenic ecosystems are the main sources for energy, building poles and livestock fodder. They probably behave like some nets carbon sinks, but there are only few studies that have focused on their carbon exchanges with the atmosphere. Preserving terrestrial ecosystems has proven essential to any emissions mitigation policy of green house gases, notably CO2. This thesis focuses on the analysis of the CO2 fluxes in three contrasting types of the ecosystem under a Sudanian climate in Benin. Specifically, it was a cultivated forest, a protected forest and a cultivated savannah. Turbulent CO2 fluxes were measured by an eddy-covariance system placed above the ecosystems. The measurements were made during variable periods of 17 months (cultivated forest), 18 months (protected forest) and 29 months (cultivated savannah). The three studied sites have been equipped by the hydro-meteorological observatory AMMA-CATCH and the national project Ouémé 2025. The CO2 fluxes data were completed by some meteorological measurements and by an inventory of dominating species the three sites. Fluxes were examined on the basis of the two main seasons imposed by the cycle of West African Monsoon. The spatial (local and regional) and temporal (hour, seasonal, annual and inter-annual) scales were considered according to the sites. Water was the main factor controlling the dynamic of the terrestrial West African ecosystems. At the daily scales, the radiation was the main driving variable of the net CO2 fluxes. Besides that radiation control, a clear relationship was observed between the net CO2 fluxes and the canopy conductance. A limited impact of saturation deficit was observed, notably during the afternoon. The soil moisture was the main factor governing the ecosystem respiration. However, no clear dependency of the ecosystem respiration on the temperature was observed at hourly scale. After long dry periods, the ecosystem respiration increased immediately in response to the first significant rains. The CO2 fluxes and the characteristics of the protected forest were always higher than those of the cultivated savannah at the daily and seasonal scales. At the annual scale, while the protected forest (Bellefoungou) and cultivated savannah (Nalohou) sequestered an average of 640 ± 50 and 232 ± 27 g C m-2, respectively considering the period of the measurements, the cultivated forest was in equilibrium with 29 ± 16 g C m-2. Overall, the three studied ecosystems were more efficient during morning and wet season than during afternoon and dry season. Finally, this study revealed that the inter-annual variability of the carbon sequestration by the cultivated savannah was mainly controlled by the ecosystem respiration variability in relation to the soil water content variation. [less ▲]

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See detailDe la magie au magique. Conscience, réalité-humaine et être-dans-le-monde chez Sartre (1927-1948)
Dassonneville, Gautier ULg

Doctoral thesis (2016)

This research deals with Sartre's early existential philosophy by resituating it in the field of French post-Comtian philosophy in the early twentieth century and by re-establishing an anthropological ... [more ▼]

This research deals with Sartre's early existential philosophy by resituating it in the field of French post-Comtian philosophy in the early twentieth century and by re-establishing an anthropological moment in which the issue of magic is explored in the psychological and social sciences. Following the different paths of the conceptual exchange through which the notion of magic becomes that the magical in Sartre's view, we study three poles of sartrian phenomenological ontology : intentional consciousness, human reality and being-in-the-world. The hypothesis advanced by this thesis is that the magical, according to different modes ranging from topicalization through obliteration, plays a determining role in the elaboration of existentialism whose genesis is traced here from Sartre's very first writings in 1927.  Faced with the legacy of a positivist anthropology in terms of an analytical methodology, Sartre privileges a synthetic approach and conceives consciousness in its affective and irrational aspects. Images of magical thought are called upon for rethinking openness to the world of consciousness and its relationship to itself and to Others. Returning to Sartrian anthropology, we question how consciousness can be grasped as an irreflexive and absolute spontaneity and how human reality is interpreted through its attitudes and behaviours; in particular through the way it faces its own freedom which is fundamentally and irremediably exposed to contradiction. This structure of human reality as existential project leads Sartre to reconsider being-in-the-world as based in originary dispossession through which ontology is brought back to the magical. [less ▲]

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See detailAspects socio-économiques et technique de la conservation du mouton Koundoum au Niger
Hamadou, Issa ULg

Doctoral thesis (2016)

Résumé Le mouton Koundoum représente le principal mouton à laine du Niger et est exclusivement élevé dans les îles et sur les bords du fleuve Niger, depuis la frontière du Mali jusqu’à Niamey. Il ... [more ▼]

Résumé Le mouton Koundoum représente le principal mouton à laine du Niger et est exclusivement élevé dans les îles et sur les bords du fleuve Niger, depuis la frontière du Mali jusqu’à Niamey. Il constitue une source de nourriture et de revenus pour les agriculteurs ruraux de cette zone. Cette race est reconnue pour sa production de laine et sa remarquable adaptation à l’humidité dans la vallée du fleuve Niger. Peu d’informations sont disponibles sur les caractéristiques de cette race alors qu’on assiste à une régression drastique de son effectif. La documentation des caractéristiques d’une race est importante pour son utilisation et sa conservation. Cette étude a été entreprise pour documenter (i) le système de production et les caractéristiques morphobiométriques du mouton Koundoum, (ii) les préférences des éleveurs et leur disposition à payer ou à recevoir une compensation pour les caractéristiques des ovins, (iii) les caractéristiques de reproduction du mouton Koundoum et (iv) les points de vue des parties prenantes potentielles susceptibles de contribuer à la réussite de la gestion et la conservation de la biodiversité des animaux d'élevage au Niger. Ainsi, pour caractériser la race et comprendre son contexte de production, une enquête a été menée auprès de 104 ménages dans quatre communes le long du fleuve Niger (Kollo, Tillabéry, Say et Tera) pendant la période d’août à décembre 2011. Neuf mesures corporelles, comprenant le poids vif, ont été prises sur 180 moutons Koundoum (101 femelles et 79 mâles). L’effectif des troupeaux de moutons varie de 2 à 60 têtes, avec une taille moyenne de huit animaux et les deux tiers des troupeaux comptant moins de 10 animaux. Principalement alimentés sur les pâturages naturels, 85,6% des troupeaux reçoivent des résidus de récolte en supplément. Seul l'accouplement naturel est pratiqué par les éleveurs et les soins vétérinaires sont limités aux anti-helminthiques et à une pharmacopée traditionnelle. L'affiliation fréquente des éleveurs à des associations professionnelles apparait comme un facteur favorable à la mise en œuvre d'un programme collectif de conservation. Le mouton Koundoum est de robe blanche ou noire, avec une fréquence plus élevée pour la couleur noire (75,6%). Les pendeloques sont présentes dans les deux sexes à des fréquences similaires, d’environ 14 %. Toutes les variables biométriques sont positivement et significativement corrélées entre elles. Le périmètre thoracique montre la meilleure corrélation avec le poids vif, tant chez les mâles que chez les femelles. Trois variables ont été sélectionnées pour la prédiction du poids vif: le périmètre thoracique, la hauteur au garrot et la longueur de la croupe. Il ressort de cette étude que la conservation in situ de la race Koundoum s’annonce comme très problématique, du fait du manque d’opportunités de marché pour la laine et de disposition des petits éleveurs à élever le mouton Koundoum en race pure. Dans le but d’objectiver ce dernier frein, la seconde étude, conduite dans la même zone de septembre 2012 à février 2013, caractérise les préférences des éleveurs pour les béliers reproducteurs et aborde leur disposition à contribuer au programme de conservation du mouton Koundoum à travers leur appréciation quantifiée des principales caractéristiques phénotypiques de la race. L'outil de l'empilement proportionnel est utilisé d'abord dans 11 groupes de discussion focalisée réunissant des éleveurs autour de la question des principaux critères de sélection de béliers reproducteurs. La méthode d'analyse conjointe multi-attributs est ensuite appliquée avec 168 propriétaires de moutons. L'estimation économétrique de la fonction d'utilité des éleveurs est réalisée avec un modèle logit conditionnel et la disposition à payer est calculée par le rapport entre chaque coefficient d’utilité des caractères et de l’attribut monétaire. Les résultats révèlent un fort rejet par les éleveurs des caractéristiques comme la laine et la robe noire et montre ainsi la faible acceptabilité d'un programme de conservation in situ. Quelques éleveurs avec une préoccupation particulière pour la conservation de la race, pour des motifs culturels, peuvent néanmoins adhérer à un tel programme de conservation, qui devrait être principalement fondé sur des stratégies ex situ. En vue de ces stratégies ex situ, il est nécessaire d’étudier les caractéristiques de reproduction chez le mouton Koundoum. La troisième étude a ainsi été conduite en station, à la ferme expérimentale et de recherche de la Faculté d’Agronomie de l’Université Abdou Moumouni de Niamey (Niger) pendant la période de décembre 2013 à avril 2014. L’étude a plus précisément déterminé les caractéristiques du cycle œstral de la brebis et quelques caractéristiques spermatiques du bélier de la race Koundoum du Niger. Ainsi, seize brebis et huit béliers Koundoum ont été utilisés pour cette étude. Les brebis ont été soumises à une observation biquotidienne de leur comportement sexuel en vue de détecter les œstrus, à l’aide de béliers boute-en-train. Les échantillons de sperme ont été recueillis à l’aide d’un vagin artificiel chez les béliers pendant les périodes d’œstrus des brebis. La motilité du sperme a été déterminée à l’aide d’un microscope et sa concentration à l’aide d’un spectrophotomètre. Sur les 16 brebis, 13 ont manifesté au moins une fois des comportements d’œstrus ayant une durée moyenne de 37,8 ± 5,8 heures avec une durée moyenne de cycle œstral de 18,1 ± 1,1 jours. La collecte de semence a pu être réalisée sur 4 béliers sur les 8 inclus dans le protocole. Les éjaculats collectés ont présenté un volume moyen de 1,03 ± 0,3 ml, une motilité de 3,4, et une concentration de 1322 ± 544 millions/ ml. La connaissance de la durée du cycle et de l’œstrus est un élément de base pour la maîtrise de la fonction sexuelle des brebis. La difficulté de collecte de la semence de béliers Koundoum devra être prise en compte dans les plans de conservation par cryogénisation de paillettes. Les informations obtenues à travers cette étude sont une base permettant de poser les premiers jalons du programme de conservation et d’amélioration de cette race. Enfin, une quatrième et dernière étude a été conduite de mars à avril 2014 pour examiner les points de vue des parties prenantes potentielles susceptibles de contribuer à la réussite de la gestion et la conservation de la biodiversité des animaux d'élevage au Niger. La recherche applique la méthodologie Q afin de révéler des discours consensuels et divergents. Après le développement de l'ensemble des affirmations sur le thème de la biodiversité (échantillon Q), les arrangements des affirmations ont été réalisées par les répondants à travers une échelle de Likert à 7 niveaux, de -3 à +3. L'analyse des données (les arrangements Q) avec le package qmethod sous le logiciel R a révélé trois points de vue distincts des parties prenantes sur l'importance de la biodiversité dans l'agriculture et l'élevage, l'équilibre entre le progrès et la conservation et les différentes méthodes de conservation. L'étude montre un consensus apparent sur l'importance de la biodiversité, qui est évidemment un sujet promu dans le pays. Derrière le consensus, différents discours sont définis qui semblent tous divisés par le même dilemme entre la conservation et le développement économique. Comprendre les différentes réponses et poids attribués à chacun des composants du dilemme guidera des campagnes de sensibilisation et aidera à identifier les intérêts divergents des parties prenantes. [less ▲]

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See detailA Feasibility Study of Direct Injection Spraying Technology for Small Scale Farms: Modeling and Design of A Process Control System
El Aissaoui, Abdellah ULg

Doctoral thesis (2016)

El Aissaoui Abdellah (2015). A feasibility study of direct injection spraying technology for Small Scale Farming: Modeling and design of a process control system. University of Liege-Gembloux Agro-Bio ... [more ▼]

El Aissaoui Abdellah (2015). A feasibility study of direct injection spraying technology for Small Scale Farming: Modeling and design of a process control system. University of Liege-Gembloux Agro-Bio Tech. Belgium. 176p., 11 tabl., 75 fig. The study aims to develop a process controller of direct injection spraying system (DIS) that can fit to carry out precise chemical application using variable rate application based on speed sensing in the context of small scale farming. It has the specific objectives of studying the feasibility of DIS by optimizing the hydraulic system and the process control designs as the main requirements for the best system reactivity and performance. The final design of DIS assessed to implement hydraulic system (hardware) and process controller (software) of a sprayer framework mounted on a rolling chariot propelled by walker operator. A logical approach is used of reviewing the state of art and formulating a specification book to develop a cost effective prototype to eventually adapt DIS expertise to the context of small scale farming. The demarche consists on giving low cost solution of variable rate technology to solve the technical problems related to usage and inefficiency of pesticide application mainly done by portable sprayers. The state of art gives a light on the development process of direct injection spraying technology (DIS) within the scope of precision agriculture progress. It also deals with technical options, advantages and problems related to DIS and control engineering solutions developed for improving spraying application efficiency and safety measures for human and environment. After that we have specified requirements of the researched DIS prototype by referring to existing art of DIS technologies and by diagnosing problems of chemical application in the context of small scale farming. It concerns specifically the technical requirements, setting values and performance of DIS process controller according to the working conditions of intensive cropping in small farming. The materials and methods consist on presenting the approach used for modeling the DIS prototype (splitting the problematic to the two main design aspects of hydraulic system and process control system) and evaluating it in laboratory conditions using simulated velocity data input. The data acquisition system is implemented for assessing the performance of DIS hydraulic and process controller performances. After that, the process controller is implemented in a cost effective electronic kit (box) to be mounted on a small sprayer framework propelled by worker. The hydraulic modeling of DIS served for optimizing the lag transport task as main problem of system reactivity performance and concentration process change. An algorithm is implemented in VB program to assess effect of hydraulic serial boom design (diameter and number of mounted nozzles in serial scheme) on flow dynamic to find compromise between lag transport, mixing ability (turbulence) and friction loss tasks that yield lateral and longitudinal uniformities application of standard boom layout. The modeling results showed lag transport and uniformity of respectively 2 s and 96 % for optimal conventional boom of 6 mm inner diameter having ten tip nozzles (ISO11003, 1.2 L/min~3bars). To solve systematic problem of lateral miss uniformity of serial boom layout (standard scheme), improved parallel boom layout (equidistant tubing lines of 4 mm diameter) is adopted for obtaining an even lag transport between nozzles. The test of parallel boom layout showed even lag transport approximating 1.5 s for ten mounted nozzles. The total response time of DIS is optimally improved to be within 2.5 s by installing electrical pumps close to boom and injecting chemical in suction side to the carrier pump assumed to perform online mixing without use of static mixer. The PID feedback controller is modeled in MATLABTM software. The process is considered as a first order process having a time constant of 0.2 s and a delay transport less than 2 s. Two control strategies of constant carrier flow control (CCFC) and total flow control (TFC) are modeled and implemented for test in laboratory conditions. Both strategies were tested and evaluated on the basis of different solicitations of variable speed input within the range of 0 - 2 m/s as a field working condition of walker operating a rolling sprayer chariot. Finally, on the basis of the results of modeling and experimental assessment, an affordable kit of PLC process controller and PWM modules for actuating carrier pump and metering pump is performed in compact electronic box for potential usage on small sprayer framework to be propelled by walker operator in agricultural field. The controller is based on a PLC microcontroller implemented for carrying out a constant carrier flow rate and a variable chemical injection rate proportionally to the operating speed. The prototype is tested for applying variable rate application using simulated step solicitations within the range of the operator working conditions of 0 - 2 m/s. The study showed the feasibility of implementing a cost effective process controller design for applying variable rate chemical in small farming context. The controller is adaptable for sprayer mounted on wheeled chariot to be propelled by worker assumed to walk at variable velocity. [less ▲]

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See detailAerothermodynamics of Pre-Flight and In-Flight Testing Methodologies for Atmospheric Entry Probes
Sakraker, Isil ULg

Doctoral thesis (2016)

Spacecraft, returning back to Earth, experience a very harsh environment during the encounter with the particles of the atmosphere. One of the major issues of the atmospheric entry is the extreme ... [more ▼]

Spacecraft, returning back to Earth, experience a very harsh environment during the encounter with the particles of the atmosphere. One of the major issues of the atmospheric entry is the extreme aerodynamic heating and the exothermic chemical reactions due to the gas-surface interaction at hypersonic free stream velocities. There is a constant effort by the space agencies to increase the understanding of the re-entry flight dynamics to optimize the spacecraft and especially its thermal protection system design. During the design process, ground tests and numerical tools are extensively used for their low cost and controlled environment abilities. However, real flight tests are indispensable for ground test and numerical tools validation. Due to high costs, such missions are rarely launched and thus there is an increasing interest in small affordable entry probes. Such platforms, once matured enough, may serve as an easily accessible tool to produce experimental data. It is the aim of this dissertation to propose tools to improve ground test capabilities and on the other hand to present the design, and using the developed tools, the testing of aerothermodynamic experimental payloads to collect flight data with a small entry probe. QARMAN (QubeSat for Aerothermodynamic Research and Measurements on AblatioN) is a triple unit CubeSat with ablative and ceramic thermal protection systems. It will perform an atmospheric entry with 7.7 km/s and a peak heat flux of 1.7 MW/m2. The aim of the in-flight experiments is to retrieve real flight data on ablator efficiency (temperature, pressure, recession) and temperature-pressure measurements for transition on the side panels. The peculiar squared geometry of QARMAN led to the development of a Flight-to-Ground Duplication methodology accounting for spacecraft geometries. It allows duplicating fully the stagnation region of a spacecraft with an arbitrary geometry in subsonic plasma wind tunnels. As a requirement of this methodology, free stream characterization techniques, specifically enthalpy measurement techniques are introduced. Experimental and numerical databases are built. A thorough ablation characterization campaign in VKI Plasmatron is conducted to provide input for building material response models. The cork P50 ablator is studied in terms of surface and sub-surface temperatures, emissivity, mass loss, char-pyrolysis layers, outgassing species and recession and swelling profiles. Similar in-flight experiments are proposed for QARMAN flight for in-depth temperature and pressure. Methods to build models for advanced data treatment are proposed. A full picture of post-flight analysis strategy is described for each study to relate the ground tools and flight data. [less ▲]

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See detailExperimental and Numerical Characterization of Damage and Application to Incremental Forming
Guzmán Inostroza, Carlos Felipe ULg

Doctoral thesis (2016)

Nowadays, product manufacturing can be divided into two groups: relatively simple products produced in a large production chain and complex (specialized) components produced in reduced batches. Within the ... [more ▼]

Nowadays, product manufacturing can be divided into two groups: relatively simple products produced in a large production chain and complex (specialized) components produced in reduced batches. Within the second group, prototyping through incremental sheet forming (ISF) has been subject of several studies. ISF refers to processes where the plastic deformation occurs by repeated contact with a relatively small tool. A crucial aspect in the ISF processes is that the final shape is determined only by the tool movement. The focus of this research is the single point incremental forming (SPIF) process variant, where a clamped sheet metal is deformed by using a relatively small spherical tool. SPIF has several advantages over traditional forming, such as the high formability attainable by the material. Different hypothesis haven been proposed to explain this behavior, but there is still not a clear and definitive understanding of the relation between the particular stress and strain state induced in the material during SPIF and the material degradation leading to localization or fracture. In this thesis, a fundamental research is proposed using the finite element (FE) code LAGAMINE, developed within the University of Liège. Numerical implementation and validation of the Gurson-Tvergaard-Needleman (GTN) damage model into this FE code is performed. An experimental test campaign is developed to characterize plastic and damage behavior and to validate the damage model for the DC01 steel grade. Finally, this damage model is applied to simulate the SPIF process in order to verify if it is capable to predict failure. The thesis discusses the material parameter identification for classical plasticity models, describing the anisotropy and hardening behavior of the sheet metal. The derivation of the equations of the numerical damage model and the efficiency of the implementation is presented in great detail. A methodology for the numerical parameter identification of the damage model is proposed, including microscopic measurements by optical microscopy and strain and displacement field measurements by digital image correlation (DIC). The identified Gurson model is applied to simulate standard SPIF geometries, like the line, cone and pyramid tests. The simulations are performed using the solid-shell element formulation and validated in terms of shape and force prediction. Literature reviews of the Gurson model and the SPIF process are also included. The experimental results show that the selected material (DC01 steel sheet) exhibits a slight anisotropic behavior and work-hardening stagnation on cyclic tests. The performed microscopic measurements are not representative of the actual damage, but they give a qualitative estimation of the physical mechanism of fracture. The initial porosity of the material was determined using optical microscopy measurements in the base material. The numerical implementation of the model is developed with all variables integrated in an implicit way, based on the backward Euler scheme. Nucleation, coalescence and shear extensions implementations are validated by results obtained from the literature. The macroscopic campaign allowed to identify the parameters for nucleation, coalescence and shear. An unique set of results matching all experiments was not possible to obtain, so different sets of parameters are retrieved following an approach that includes inverse modeling and sensitivity analysis. A numerical-experimental comparison of strain values in the loading direction shows that the model is able to correctly predict the strain distribution except during localization of the strain. Globally, the obtained set of material parameters is in good agreement with the experimental results. For SPIF FE simulations, the results of the shape prediction are in good agreement with the experimental results, both for the line and pyramid test. Nevertheless, the force prediction is too high compared to reference values. On the other hand, the GTN model is capable to detect failure in a pyramid and a cone, but the prediction is too premature compared to the experimental failure angle for the same material and geometry. An accurate prediction of failure for the SPIF process was not possible to achieve. The GTN model extended to shear presents inherent flaws that prevent an accurate prediction of the failure angle for the SPIF process. Hence, an extensive research on the damage mechanisms leading to fracture for SPIF cannot rely (only) on the GTN model. The classical coalescence model of the GTN model is insufficient to correctly predict failure. Hence, it is recommended that further analysis concentrates on the description of this particular stage of damage evolution. During the development of this thesis, a robust implementation of the GTN model into the FE code LAGAMINE was done, including an extensive experimental database of microscopic and macroscopic measurements for the DC01 steel sheet. Other phenomena can be explored thanks to this model. [less ▲]

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See detailCo-simulation of Electromagnetic Transients and Phasor Models of Electric Power Systems
Plumier, Frédéric ULg

Doctoral thesis (2016)

This study investigates and improves methods used for the combination of phasor and electromagnetic transients time domain simulations of power systems. It involves the study of the protocols of ... [more ▼]

This study investigates and improves methods used for the combination of phasor and electromagnetic transients time domain simulations of power systems. It involves the study of the protocols of computation, the comparison of the different kinds of boundary conditions used to represent one sub-system when simulating the other, and the interfacing of phasor and electromagnetic transients models. The Nordic system has been used to realize the tests. Illustrative simulation results are reported for the case of a single and of multiple boundary buses between the sub-systems. [less ▲]

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See detailSynthesis and Physical Properties of Helical Nanosized Quinoline-based Foldamers: Structure, dynamics and photoinduced electron transport
Li, Xuesong ULg

Doctoral thesis (2016)

Herein, synthesis, characterization and application (photoinduced electron transport) of nanosized quinoline-based foldamers have been explored. With double segment strategy, a variety of helical ... [more ▼]

Herein, synthesis, characterization and application (photoinduced electron transport) of nanosized quinoline-based foldamers have been explored. With double segment strategy, a variety of helical nanosized foldamers (up to 96 quinoline units) were successfully prepared based on 8-aminoquinoline-2-carboxylic acid monomer. The dynamic properties in gas phase and solution were investigated. Ion mobility mass spectrometry afforded access to the conformation state of foldamers in gas phase; DOSY and fluorescence anisotropy assessed the diffusion (translational and rotational, respectively) of foldamers in solution. All of these techniques revealed that quinoline-based foldamers are rigid and that helical conformation is conserved. Photoinduced electron transport through nanosized foldamer was also studied and the mechanism and the transport ratios were revealed. [less ▲]

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See detailEfficient methods for large-scale time-harmonic wave simulations
Marsic, Nicolas ULg

Doctoral thesis (2016)

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See detailCARRIÈRES MIGRATOIRES ET POLITIQUE D’INTÉGRATION DANS LA RÉGION DE MADRID. L’EXEMPLE DES MIGRANTS ADULTES DANS LA VILLE DE PARLA (2007-2012)
Brey, Elisa ULg

Doctoral thesis (2016)

This dissertation analyses the migratory carreers of adult migrants settled in the urban outskirts of Madrid, in Spain, during the first years of the economic crisis (2007-2012). The aim is to understand ... [more ▼]

This dissertation analyses the migratory carreers of adult migrants settled in the urban outskirts of Madrid, in Spain, during the first years of the economic crisis (2007-2012). The aim is to understand the dynamics of migratory carreers through the access to a residence permit, the labour and the housing market. To achieve this goal, semi-structured interviews have been conducted with migrants from Morocco, Romania, countries of Subsaharan Africa and the Andean Community (Ecuador, Colombia, Bolivia and Peru). Interviews and observations have also been conducted with leaders of local associations and representatives of municipal services to which migrants have access. A typology is proposed, considering that migratory carreers can adopt regular or informal dynamics, following the characteristics of a community or a society. [less ▲]

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See detailBeyond the Line: Murray Bail's Spatial Poetics
Herbillon, Marie ULg

Doctoral thesis (2016)

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See detailLa justice pénale internationale à l'épreuve des droits humains : étude de la privation de liberté devant la Cour pénale internationale
Deprez, Christophe ULg

Doctoral thesis (2016)

Entre instrument de protection des libertés fondamentales et menace à l'égard de ces mêmes libertés, l'activité pénale est un phénomène cerné de paradoxes. Les règles de protection des droits humains ont ... [more ▼]

Entre instrument de protection des libertés fondamentales et menace à l'égard de ces mêmes libertés, l'activité pénale est un phénomène cerné de paradoxes. Les règles de protection des droits humains ont notamment pour ambition de contenir ces paradoxes : en encadrant le pouvoir de contrainte que l'autorité répressive peut exercer sur les individus, ces normes essentielles doivent permettre de garantir une justice pénale qui demeure fidèle aux principes qu'elle entend défendre. Mais quelle peut bien être l'emprise des droits humains sur l'action du juge pénal international ? Dès lors que le droit international des droits de l'homme a été pensé et conçu pour circonscrire l'autorité des États, qu'en reste-t-il lorsqu'on cherche à l'appliquer – en particulier – à la Cour pénale internationale ? Dans quelle mesure et sur la base de quel(s) fondement(s) juridique(s) cet acteur répressif d'un genre nouveau est-il tenu au respect de règles auxquelles il n'a pas expressément souscrit ? Les spécificités de la justice pénale internationale – et, singulièrement, la gravité des crimes ayant favorisé son émergence – réclament-elles une adaptation du niveau de protection accordé aux suspects et accusés internationaux ? Quel accueil le Statut de la Cour pénale internationale et les règlements qui l'accompagnent réservent-ils aux standards pertinents, en particulier en matière de privation de liberté ? La jurisprudence de la Cour révèle-t-elle une pratique conforme à ces standards ? Le projet de recherche vise à apporter un éclairage sur l'ensemble de ces questions et, ainsi, à mettre la justice pénale internationale à l'épreuve des droits humains. [less ▲]

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See detailDiagnostic préalable à un contrat d'axe sur la ligne SNCB 40 Liège-Guillemins - Visé. Etude du potentiel de l'outil contrat d'axe en Wallonie et de la densification des gares de la ligne 40
Wilmotte, Pierre-François ULg

Master's dissertation (2016)

Le travail vise à alimenter la réflexion menée par le consortium Pluris - Trame - B. Bianchet à propos de l'élaboration d'un Schéma de Développement Territorial (SDT) pour l'arrondissement de Liège : d ... [more ▼]

Le travail vise à alimenter la réflexion menée par le consortium Pluris - Trame - B. Bianchet à propos de l'élaboration d'un Schéma de Développement Territorial (SDT) pour l'arrondissement de Liège : d'une part, étudier le potentiel des quartiers de gare en région liégeoise et, d'autre part, à voir si l'outil des "Contrats d'axe", développés en France, pourrait être pertinent dans le cadre wallon. La recherche a été appliquée à un axe ferroviaire de la région de Liège. [less ▲]

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See detailStimuli-responsive self-assembled macromolecular systems with potential drug delivery applications: structural characterization by Small-Angle Neutron Scattering
Joset, Arnaud ULg

Doctoral thesis (2016)

Colloids are known since the early 19th century but they have mainly sparked interest since the last few decades thanks to their use in biomedical applications or in the design of new materials. The aim ... [more ▼]

Colloids are known since the early 19th century but they have mainly sparked interest since the last few decades thanks to their use in biomedical applications or in the design of new materials. The aim of this thesis is the study of stimuli-responsive colloids by Small-Angle Neutron Scattering (SANS). The stimuli may be the pH, the temperature, the addition of a ligand or of metallic ions or a combination of them. SANS is a useful technique which provides information about the internal structure of nano-objects but also, if appropriate conditions are met, about the organization of the objects in solution. Several samples built from the auto-assembly of block copolymers and liposomes have been prepared. The macroscopic cross sections have been modeled with the aim to infer the main structural parameters of the samples: the global size, the polydispersity, the structure and volume occupied by the hydrophilic and hydrophobic components inside the nano-objects. The SANS measurements have been performed as a function of the intensity of the stimulus, in order to quantify the evolution of the structural parameters. The first experimental part focuses on micellar samples built from sequenced block copolymers. The blocks may be biodegradable (e.g., poly(ε-caprolactone)), biocompatible (e.g., poly(ethylene oxide)), pH-sensitive (e.g., poly(2 vinylpyridine), poly(acrylic acid)) or temperature-sensitive (e.g., poly(N-isopropylacrylamide)). The influence of the concentration and the formation of bridges between micelles have been investigated through the analysis of metallo-supramolecular micellar gels resulting from the self-assembling of polystyrene-block-poly(tert-butylacrylate) PS-b-PtBA-tpy (tpy stands for terpyridine) block copolymers in the presence of transition metal ions. The second part focuses on the analysis of liposomes interacting with an increasing concentration of Randomly Methylated β-cyclodextrins (RAMEB). This part is divided into two chapters. The first one deals with liposomes mainly composed of dimyristoylphosphatidylcholine (DMPC) and the second one investigates the effects of cholesterol doping on the same DMPC liposomes interacting with RAMEB. [less ▲]

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See detailLa disponibilité et le prix du foncier à vocation économique: quel impact sur le développement économique en Wallonie?
Vandermeer, Marie-Caroline ULg

Doctoral thesis (2016)

This doctoral dissertation concerns the policy of land production related to economic land in Wallonia. This policy corresponds to the development of economic estates by public authorities, through ... [more ▼]

This doctoral dissertation concerns the policy of land production related to economic land in Wallonia. This policy corresponds to the development of economic estates by public authorities, through economic development agencies, to accommodate businesses. It is based on the argument according to which the availability of land – cheap if possible – is an essential factor in territorial attractiveness and competitiveness. The reflections presented in this dissertation originate from the discrepancy between this argument and the scientific literature devoted to regional development. Indeed, unlike elected representatives and economic development agencies, scholars active in the field of regional sciences only very rarely refer to the impact of the land markets on levels of development. Rather than focusing on the theme of land prices and land availability, regional scientists underline the importance of intangible factors such as innovation, education, integration into networks, territorial identity, strategic management or governance. In view of this difference, it seems appropriate to assess the spatial and economic effectiveness of the Walloon policy of land production. To do this, our wish is to objectify the real role of the availability and the price of economic land on territorial development. The first part of the dissertation develops a reflection on the literature dedicated to the relationships between land and property markets and regional development. It leads to highlight the need to develop knowledge on the impact of land and property markets on business competitiveness, regional attractiveness and economic development. The second part is devoted to the study of the availability of economic land and aims to assess the spatial effectiveness and the economic effectiveness of policies which offer an important quantity of economic land. To do this, statistical analyses were conducted on two study areas: the Northwest Europe and Belgium. As regards spatial effectiveness, the results underline significant national differentials in terms of land consumption on the one hand, while highlighting the economic sprawl that characterises France and Belgium on the other hand. As regards economic effectiveness, our results show that the impact of the development of economic estates on growth depends largely on regional contexts. Our analyses identified three regional profiles. First, urban regions, where land availability only plays a marginal role, most likely owing to the presence of numerous activities that are not very extensive spatially, yet very productive in terms of added value. Secondly, intermediate regions, where the availability of economic land has a real impact on development. However, it would appear that the profile of these regions is adapted to the presence of activities which, like logistics, generate a limited amount of jobs and added value per surface unit. Thirdly, rural regions, where the opening of land to urbanisation does not deliver the desired results. In these regions, the availability of land is not a sufficient condition for economic growth and job creation. However, we have to precise that the Belgian rural regions are rather similar to intermediate regions, probably thanks to their good connectivity. The third part concerns the study of the economic land prices. It tends to assess the impact of these prices on company property costs. The developed statistical analysis is based on annual accounts of companies with one reporting unit localised in Walloon economic estates. Results suggest that property costs are rather low. On average, they represent 1.4% of all their operational costs and 5.4% of their added-values. By contrast, labour costs are eight times higher. In addition, our analyses suggest that an increase in land prices would have a limited impact on property costs. These results tend to invalidate the hypothesis that low land prices are a key determinant of regional development. Although, property costs are highly dependent on the business sector and the size of firms. For instance, for logistic companies and small firms, property costs represent more than 10% of their added-values and 2% to 5% of their operational costs. These results tend to highlight the fact that high land prices can have a negative impact on the development of these companies. As a final point, our conclusion discusses the recommendation that economic land supply policies must be adapted according to both, the profile of the territories and the profile of the firms. Indeed, in urban regions, land supply policies aiming to supply an important land supply at low price is probably inefficient from an economic standpoint. By contrast, economic development can be expected in intermediate regions with active land policies dedicated to land-intensive activities. Moreover, a specific attention should be paid to small companies. [less ▲]

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See detailApproche contingente du design du système d’information comptable dans les PMI tunisiennes : une étude fondée sur les équations structurelles
Ghorbel, Jihene ULg

Doctoral thesis (2016)

Malgré les recherches sur le système d’information comptable dans les PME, les résultats trouvés sont mitigés et contradictoires. Ainsi, nous essayons à travers ce travail de contribuer au débat relatif ... [more ▼]

Malgré les recherches sur le système d’information comptable dans les PME, les résultats trouvés sont mitigés et contradictoires. Ainsi, nous essayons à travers ce travail de contribuer au débat relatif au design du système d’information comptable dans les PMI des pays en voie de développement comme la Tunisie. En effet, le système d'information comptable, considéré comme un facteur de compétitivité des entreprises, fournit aux gestionnaires l'information comptable pertinente pour les aider dans leur prise de décision. Nous nous intéressons à une série de facteurs structurels et comportementaux susceptibles de mieux cerner le design du système d’information comptable. Une étude empirique menée par l'adoption de la technique du questionnaire auprès de 221 entreprises tunisiennes opérant exclusivement dans le secteur industriel montre que le design du système d'information comptable est influencé par plusieurs facteurs contextuels, en utilisant les méthodes des équations structurelles. [less ▲]

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See detailValidation of a Multiplex HPLC MS/MS assay for the measurement of steroid hormones
Rademaker, Gilles ULg

Master's dissertation (2016)

Facing an improvement of the quality assurance in all the laboratory, the validation of methods has become a step that cannot be got round. The objective of this work is the validation of a Protein ... [more ▼]

Facing an improvement of the quality assurance in all the laboratory, the validation of methods has become a step that cannot be got round. The objective of this work is the validation of a Protein-Precipitation HPLC-MS/MS method for the measurement of steroid hormones (Aldosterone, Androstenedione, Cortisol, 17-OH Progesterone, DHEAS and Testosterone). To achieve this purpose, a precision, recovery, linearity, carry over assay and a limit of quantification are performed. After collection of the data, results are calculated and statistically analysed. They allow to set boundaries to the method and to understand more easily how we could improve it. The results show that the method is effective for all hormones except the aldosterone, for which the method still has to be improved. Moreover, a comparison of the analysis of the testosterone between Cobas and HPLC MS/MS is made. In the lab, this hormone is analysed with Cobas but a transition to the HPLC MS/MS can be done because the results are satisfactory. [less ▲]

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See detailL'identité sourde : entre handicap, culture et stigmate
Darcis, Coralie ULg

Master's dissertation (2016)

De tout temps la surdité a été appréhendée d’un point de vue médical par les sciences, avec comme objectif de rendre l’ouïe à ceux ne l’ayant pas. Cependant, depuis plus d’une vingtaine d’années, certains ... [more ▼]

De tout temps la surdité a été appréhendée d’un point de vue médical par les sciences, avec comme objectif de rendre l’ouïe à ceux ne l’ayant pas. Cependant, depuis plus d’une vingtaine d’années, certains auteurs des sciences sociales s’intéressent à cet objet d’un point de vue culturel : la surdité en tant que culture. Des auteurs se penchent également sur la notion d’ « identité sourde », supposée recouvrir une réalité homogène. Cependant, plusieurs auteurs écrivent sur le sujet, tout en montrant la complexité de la réalité couverte par cette expression. Dès lors, si l’expression « identité sourde » ne correspond pas un bloc monolithique, que recouvre-t-elle actuellement en Belgique francophone ? Pour répondre à cette première question, il est tout d’abord nécessaire de s’en poser une seconde : comment et autour de quelles dynamiques l’identité de la personne sourde se construit-elle ? Dans ce mémoire, nous chercherons donc à apporter des réponses à ces deux questions à travers, d’une part, la construction d’une revue de la littérature scientifique traitant du sujet et, d’autre part, l’analyse d’un matériau empirique récolté auprès de différents informateurs sourds et entendants. [less ▲]

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See detailInfluence du tabagisme sur la santé parodontale
SALHI, Leila ULg

Master of advanced studies dissertation (2016)

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See detailFunction-based Analyses of Bacterial Symbionts Associated with the Brown Alga Ascophyllum nodosum and Identification of Novel Bacterial Hydrolytic Enzyme Genes
Martin, Marjolaine ULg

Doctoral thesis (2016)

Marine macroalgae are highly colonized by microorganisms, with which they maintain a close relationship characterized by both beneficial and detrimental interactions. Alga-associated bacteria have notably ... [more ▼]

Marine macroalgae are highly colonized by microorganisms, with which they maintain a close relationship characterized by both beneficial and detrimental interactions. Alga-associated bacteria have notably developed a range of enzymes enabling them to colonize the host surface and to use algal biomass as a carbon source. The hydrolytic potential of these bacteria, however, has been investigated almost solely at individual scale. Studies have shown the ability of some seaweed-associated bacterial strains to hydrolyze lipids, algal-cell-wall polysaccharides, and other sugars. In this work we aimed to investigate the hydrolytic potential of the bacterial microbiota associated with the brown alga Ascophyllum nodosum. For this we employed two complementary function-based approaches: functional metagenomics applied to this microbiota and functional analysis of the cultivable fraction thereof. By functional metagenomics, we identified numerous esterase genes, a beta-glucosidase gene, and an endocellulase gene. The cellulase was purified and biochemically characterized, showing interesting biotechnological features such as halotolerance and activity at low temperature. Furthermore, we assigned tentative origins to the identified genes, thus getting a glimpse of the bacterial taxa associated with the studied alga. Secondly, we investigated the cultivable surface microbiota associated with three A. nodosum samples. More than 300 bacteria were isolated, assigned to a bacterial taxon and screened for algal-polysaccharide-degrading enzymes (agarase, iota-carrageenase, kappa-carrageenase, and alginate lyases). This allowed the identification of several polysaccharolytic isolates, some of them likely to be new strains or novel species, belonging to two classes: the Flavobacteriia and the Gammaproteobacteria. Subsequently, we constructed and screened two plurigenomic libraries, each produced with the genomes of five representative isolates of each class, and identified several functional genes. With this work we highlight the presence of A. nodosum-associated bacterial taxa likely to entertain a privileged relation with seaweeds and having developed a range of hydrolytic activities assumed to enable them to associate with algae. We also provide information (taxa, abundances, genomic potential) on macroalgal-polysaccharide-degrading bacteria, in which interest has grown over the last ten years. [less ▲]

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See detailUrban megaprojects-based approach in urban planning: from isolated objects to shaping the city:The case of Dubai
Aoun, Oula ULg

Doctoral thesis (2016)

Urban megaprojects are at the core of cities’ re-imaging and marketing. As large-scale development projects, they are considered as a globalization product, marked by a search for spectacle and visibility ... [more ▼]

Urban megaprojects are at the core of cities’ re-imaging and marketing. As large-scale development projects, they are considered as a globalization product, marked by a search for spectacle and visibility. In Dubai, UMPs have constituted in recent years the main tool in drawing a city image that aims to compete with the world global cities. Through UMPs, an economy based on spectacle and fascination is being deployed, within a complex system of governance that encompasses family ties, business logic and individualist visions. UMPS are not exceptions or isolated developments, they are in Dubai, a mean through which the city is expanding and being managed. UMPs are here the backbone public planning instrument to what we can call a UMPs-based approach to planning and development. Paradoxically, it is these very large projects, usually associated to urban fragmentation that allow, through their form and processes, the emergence of forms of regulation that articulate actors, institutions, interests, resources, spaces and scales. These adaptations and negotiations are orchestrated in a strategic pilotage manner, through informal, often unveiled ad hoc regulatory spaces. The ultimate goal is to ensure a certain synchronization between temporalities and project through a continuous logic of complementarity and competitiveness. [less ▲]

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See detailẾtude de l’émergence des organisations pastorales et de leur rôle dans les processus de gestion partagée de la vallée de la Tarka dans les départements de Bermo et Dakoro (Centre sud du Niger)
Ibrahim, Habibou ULg

Doctoral thesis (2016)

Cette thèse vise à analyser les organisations pastorales et leurs rôles dans la gestion des conflits fonciers. En Afrique subsaharienne et particulièrement au Niger, le foncier est au centre des enjeux de ... [more ▼]

Cette thèse vise à analyser les organisations pastorales et leurs rôles dans la gestion des conflits fonciers. En Afrique subsaharienne et particulièrement au Niger, le foncier est au centre des enjeux de l’agro-pastoralisme. La sécurisation des droits d’accès aux ressources et des systèmes de tenure foncière sont essentiels pour la gestion et la résolution des conflits fonciers (Herrea et al., 2007). La région de Maradi constitue la zone de contact entre le Nord pastoral et le Sud agricole. Dans cette partie centrale où la pression foncière, aggravée par la croissance démographique, se pose avec acuité, le spectre des conflits fonciers est malheureusement devenu un phénomène chronique, une donnée permanente (GADO., 2000). La pluralité des normes et plusieurs sources de droit contribuent à complexifier le règlement des litiges fonciers entre acteurs dans les départements de Dakoro et Guidan Roumdji (Moutari., 2001). Or la dynamique globale des systèmes d’élevage est déterminée par la complémentarité des espaces agro-pastoraux. Cette complémentarité est remise en cause par ces pressions foncières et suscite des changements organisationnels dans les communautés du centre Sud du Niger (Yamba., 2004 ; 2000). C’est le rôle des associations pastorales à Dakoro et Bermo qui est l’objet de cette recherche. En effet les organisations paysannes en Afrique Subsaharienne et au Niger en particulier jouent un rôle important dans la définition des politiques agricoles et deviennent des conditions indiscutables de la réussite des actions à promouvoir à l’échelle locale (Courade et Deveze., 2006 ; Mercoiret, 2006 ; Mercoiret et al. 2004). La méthodologie de travail relève de l’approche ethnographique. Les outils et instruments d’enquête sont les questionnaires et les entretiens ouverts avec les acteurs locaux sur les dynamiques territoriales, les modes d’action des associations pastorales et les conflits fonciers. Les résultats viennent aussi des travaux et des documents des projets, des ONG et des rapports des services techniques de l’Etat. Pour un souci de fiabilité des données, nous avons tenu à réaliser des séances de restitution des données et de triangulations pour confronter les informations de diverses sources. Au total 104 personnes sont enquêtées dont 30 % auprès des associations. Ces investigations ont concerné aussi les secrétaires des commissions foncières, les préfets, les agents des projets et des ONG et le président du tribunal de Dakoro ainsi que les leaders pastoraux, les transhumants, les agriculteurs et associations pastorales. [less ▲]

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See detailBaldassarre Turini da Pescia, une vie au service de l’art. Le rôle et les contacts artistiques d’un familier des Médicis dans la Rome du Cinquecento
Trizzullo, Eva ULg

Master's dissertation (2016)

« Giulio intanto, essendo molto dimestico di messer Baldassarri Turrini da Pescia, fatto il disegno e modello […] un palazzo » : Vasari célèbre ici la commande la plus brillante de Baldassarre Turini ... [more ▼]

« Giulio intanto, essendo molto dimestico di messer Baldassarri Turrini da Pescia, fatto il disegno e modello […] un palazzo » : Vasari célèbre ici la commande la plus brillante de Baldassarre Turini. Cette villa somptueuse et décorée par les talentueux élèves de Raphaël n’est pas l’unique réalisation dont il souligne les qualités. Des tableaux commandés à Léonard de Vinci, une chapelle où intervint Raffaello da Montelupo, des liens d’amitié avec Raphaël : Turini est souvent présent dans le récit vasarien. Dans mon mémoire, je me suis penchée sur le rôle artistique de ce personnage, qui n’avait que sporadiquement suscité l’attention des spécialistes. Fondant ma recherche sur une abondante documentation archivistique, essentiellement épistolaire, conservée à l’Archivio di Stato de Florence, j’ai voulu montrer comment, à l’occasion de plusieurs commandes pontificales, Turini se vit confier des fonctions d’intermédiaire artistique. Il supervisa des projets de grande ampleur et entra ainsi en contact avec les artistes les plus remarquables de son temps. J’ai mis en lumière ses premiers pas en tant que proche collaborateur du pape et de sa famille, notamment en tant qu’ambassadeur de Laurent de Médicis à Rome. Dès 1514, ses lettres révèlent des contacts fréquents avec le sculpteur Baccio Bandinelli ou l’orfèvre Caradosso. Léon X sollicita son expertise pour l’organisation de sa fastueuse entrée à Florence en 1515. L’année 1518 correspond à l’apogée de la carrière de Turini et à l’affirmation de son rôle de médiateur artistique. Dans l’effervescence artistique liée au mariage très stratégique de Laurent de Médicis avec la nièce de François Ier, la cour pontificale gratifia le roi d’une série de cadeaux diplomatiques. Parmi eux, quatre tableaux au moins furent commandés à Raphaël. Les lettres échangées avec le secrétaire de Laurent témoignent de l’ampleur des prérogatives de Turini, qui sut faire apprécier sa grande efficacité pratique. En contact permanent avec Raphaël et son atelier, il agissait comme une personne de référence, informant le duc de la progression des commandes et prenant même en charge l’envoi des œuvres vers la France. C’est ainsi qu’il obtint la très haute fonction de dataire apostolique, qui lui conféra un statut privilégié au sein de la curie. Loin d’être écarté de la sphère artistique, il se vit alors confier la responsabilité de mobiliser des fonds nécessaires à la construction de l’église nationale des Florentins à Rome. Cette nomination marqua aussi le début de contacts étroits et ininterrompus entre Turini et Raphaël. Fait significatif : c’est Turini que le grand artiste désigna comme son exécuteur testamentaire. Par la suite, Turini favorisa le travail des élèves de Raphaël auprès du pape, encourageant leur intervention dans les Stanze, et les employant au même moment à la décoration de sa propre villa. À son tour, Clément VII nomma Turini nonce apostolique et lui confia le soin de réceptionner le salaire de Giulio Romano pour son travail dans la Salle de Constantin au Palais du Vatican. Enfin, dans un geste ultime de fidélité envers ses principaux protecteurs, Turini supervisa la réalisation des tombes de Léon X et de Clément VII en l’église Santa Maria sopra Minerva. Une nouvelle fois, sa correspondance révèle un profil de véritable homme de terrain, et un personnage autoritaire et influent auprès des artistes. [less ▲]

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See detailPour une sociologie de la littérature en milieu minoritaire. Analyse des discours (méta)littéraires associés à la littérature acadienne
Nicaise, Nicolas ULg

Doctoral thesis (2016)

Plus qu’un objet stabilisé, notre parti-pris est d’étudier, dans cette thèse, le phénomène de la littérature en milieu minoritaire en cherchant à montrer, par une approche systémique, comment la ... [more ▼]

Plus qu’un objet stabilisé, notre parti-pris est d’étudier, dans cette thèse, le phénomène de la littérature en milieu minoritaire en cherchant à montrer, par une approche systémique, comment la littérature acadienne se structure et s’institutionnalise. C’est à partir de l’étude d’un réseau d’acteurs et d’instances ainsi que des pratiques discursives littéraires et (méta)littéraires qui construisent cette littérature qu’il nous apparaît possible d’interroger – aux croisements de multiples courants théoriques empruntés à la sociologie de la littérature –, les relations complexes entre textes et contexte. L’objectif n’est donc pas seulement de modéliser un milieu littéraire, mais de dégager, à partir des textes de multiples acteurs du milieu, les configurations poétiques, les représentations discursives comme les conditions et les paramètres de fonctionnement du milieu. Pour autant, il ne s’agit pas d’isoler un milieu littéraire, mais d’observer comment celui-ci émerge et intègre un système plus vaste en questionnant nos représentations du littéraire. [less ▲]

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See detailMarket Dynamics in the Financial Industry - Essays on Interdependence and Market Timing
Biell, Elisabeth ULg

Doctoral thesis (2016)

The global financial crisis and the subsequent sovereign crisis are painful reminders of how the standards of financial markets are profoundly challenged in times of crisis. The main lesson is that the ... [more ▼]

The global financial crisis and the subsequent sovereign crisis are painful reminders of how the standards of financial markets are profoundly challenged in times of crisis. The main lesson is that the structural changes and the increased risk of shock transmissions require a more accurate risk assessment that captures the complexity of market dynamics. Based on an empirical approach, this thesis aims at loosening a priori assumptions common in literature in order to develop new methodologies that are more robust and more flexible to the dynamics of changing market conditions. The first aspect of market dynamics addressed in this thesis is the dependence structure of financial markets. The connectedness of the banking and sovereign sectors is dynamically assessed on the basis of daily CDS spreads using complex networks. We turn away from the traditional linear correlation measures and use copula theory to account for extreme events and tail dependence, which is crucial when studying credit and default risk. Through the calculation of minimum spanning trees, our methodology evaluates the transmission pattern of shocks over time and their propagation across geopolitical borders. Going beyond the analysis of simple interdependence, we apply a structural break analysis to measure a contagion index that captures increased co-movements in the network. This thesis tackles a second aspect of market dynamics which relates to major events in the life of a company affecting a company’s market value. By means of operational loss events and cross-listing decisions, we illustrate our refined event study technique that overcomes the drawback of a priori assumptions about the event date. In addition to the reaction magnitude, our approach investigates the point in time when most of the market reaction takes place by highlighting two variables: the start and the length of stock markets' responses. [less ▲]

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See detailContribution à l’étude de la morphologie et du développement de l’encéphale, en particulier du cervelet, chez le mouton
Salouci, Moustafa ULg

Doctoral thesis (2016)

De nombreuses maladies virales émergentes chez le mouton génèrent des anomalies congénitales au niveau du système nerveux central (SNC), or, peu d'informations sont disponibles dans la littérature sur ... [more ▼]

De nombreuses maladies virales émergentes chez le mouton génèrent des anomalies congénitales au niveau du système nerveux central (SNC), or, peu d'informations sont disponibles dans la littérature sur l’anatomie et le développement du cerveau du mouton, en particulier en ce qui concerne le cervelet. Par ailleurs, il s’avère que le mouton pourrait représenter un bon modèle expérimental animal pour l’étude de certaines pathologies survenant pendant le développement embryonnaire de l’encéphale. Au cours de cette thèse, nous avons présenté les résultats d’une série de dissections de l’encéphale du mouton afin de confronter nos résultats aux descriptions d’anatomie classique et de comparer ces résultats avec le bovin qui est souvent considéré comme animal de référence quand on parle de « ruminants ». Ensuite, nous nous sommes intéressés au développement de deux types de cellules au sein du cervelet, qui sont très peu connues chez le mouton. Ce travail a été réalisé en deux phases. La première a consisté à étudier le développement des cellules de Purkinje dans des coupes de cervelet de fœtus à différents âges de gestation et colorées à l'hématoxyline-éosine, violet de crésyl ou Klüver-Barrera. Au cours de cette étude, nous avons observé les cellules de Purkinje dès le 100ème jour de gestation. Des degrés variables de développement des cellules de Purkinje ont été observés dans différentes zones du cervelet. Nos résultats suggèrent que le développement des cellules de Purkinje débute dans les régions caudales du cervelet et dans le vermis avant de concerner les hémisphères cérébelleux. L'alignement des cellules de Purkinje était très régulier dans les régions caudales du cervelet. Une absence partielle des cellules de Purkinje dans les régions rostrales du cervelet a été observée chez les fœtus et l'adulte. Dans la première semaine après la naissance, certaines cellules de Purkinje ectopiques ont été observées dans la substance blanche du cervelet. Au cours de la seconde partie de notre thèse. Nous avons étudié le développement des astrocytes qui constituent la plus grande population de cellules gliales dans le cerveau et jouent des rôles très importants dans le développement du système nerveux central. Cette étude a été réalisée au moyen d’une technique immunohistochimique. L'utilisation du marqueur de la GFAP (protéine acide glio-fibrillaire) a montré plusieurs variations dans le degré de développement des astrocytes dans les différentes zones du cervelet du mouton pendant la vie fœtale. Au cours du 60ème jour de gestation, les astrocytes se trouvent au niveau du toit du quatrième ventricule. Pendant leur développement, les cellules radiales se transforment en astrocytes (cellules de Bergman) à partir du 100ème jour de gestation. Nos observations suggèrent que le développement des astrocytes débute au niveau de la substance blanche des zones ventrales des parties caudales du cervelet. Ceux-ci se distribuent ensuite dans les régions les plus rostrales du cervelet. Ce développement commence dans le vermis avant d’atteindre les hémisphères cérébelleux. Certaines similitudes ont été confirmées pour de nombreux aspects développementaux entre l’homme et le mouton dans le cadre de l’utilisation du mouton en tant que modèle animal. Les résultats obtenus durant cette thèse ont permis de mieux comprendre le développement normal des cellules de Purkinje et des astrocytes. Ils permettent de compléter les connaissances déjà acquises sur le développement du cervelet et d’établir des bases importantes pour de futures études portant sur les fonctions et la physiologie des astrocytes et des cellules de Purkinje ainsi que les modifications pouvant survenir lors de pathologie tant chez l’homme que chez le mouton. [less ▲]

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See detailTranscendentalism and Sublime (Post)Nature in American Literature: From Self-Discovery to Self-Destruction
Lombard, David ULg

Master's dissertation (2016)

Using the philosophy of Transcendentalism and the aesthetics of the sublime as comparative elements, this master thesis provides a diachronical analysis of a delimited corpus of (Native) American ... [more ▼]

Using the philosophy of Transcendentalism and the aesthetics of the sublime as comparative elements, this master thesis provides a diachronical analysis of a delimited corpus of (Native) American literature, which discusses representations of the (post)natural world and the self, aimed at drawing ecocritical conclusions. The author considers literary works from various genres—travelogues, essays, memoirs, novels, poems and non-fiction works—that were written by authors coming from significantly different periods. [less ▲]

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See detailLa politique de soins de santé aux personnes âgées en Belgique: Perspectives de finances publiques
Piron, Damien ULg

Master of advanced studies dissertation (2016)

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See detailMechanical design, control and optimization of a hybrid solar microgrid for rural electrification and heat supply in sub-Saharan Africa
Altés Buch, Queralt ULg

Master's dissertation (2016)

This thesis aims at developing, optimizing and controling a hybrid solar microgrid for rural electrification and heat supply in sub-Saharan Africa. The considered system includes PV, Parabolic Trough ... [more ▼]

This thesis aims at developing, optimizing and controling a hybrid solar microgrid for rural electrification and heat supply in sub-Saharan Africa. The considered system includes PV, Parabolic Trough Collectors, Organic Rankine Cycle and LPG generator, as well as chemical battery storage and thermal energy storage. The work focuses on multiple aspects of the ongoing development of solar hybrid microgrids for the rural electrification of remote areas in Lesotho. These aspects range from very specific improvements (the mechanical design of a high expansion ratio expander) to the more global evaluation of their impact once included into a complex micro-grid system. Special attention has also been paid to the links between thermal and electrical demands. The main contributions of this thesis are: – The mechanical design of a high expansion ratio scroll expander, involving drawing, machining and assembly of the parts. – The detailed model of an organic Rankine cycle with the purpose of evaluating the improvement brought by the high expansion ratio scroll expander and mapping the ORC performance. – A building model developed to predict the thermal loads of a health clinic in rural communities of Lesotho. The developed lumped-parameter model can be used for various building typologies and communities. The model is designed to be as generic and simple as possible, and contrasts with the data-intensive models generally proposed in the literature. – The gathering of monitoring and weather data relative to a health clinic in Lesotho, and their use for the calibration of the building model. – A microgrid model built by interconnecting all of its subcomponent models. A rule- based control strategy is developed, accounting for interactions between thermal and electrical loads, and dispatching heat and power flows of each component in order to cover the demand while minimizing the fuel consumption. – A particle-swarm optimization model used to optimize the microgrid under different cost assumptions and control strategies. The above models prove that the system performs better with the developed high expansion ratio expander. The maximum output power of the ORC is increased by 33%, and the fuel consumption of the microgrid is reduced by 25%. For the studied community of Ha Nkau in Lesotho, the determined optimal system infrastructure is composed of PV (65 kW) and batteries (259 kWh) only, and the optimum control strategy achieves a levelized cost of electricity of 0.202 USD/kWh. Fuel consumption is mainly due to the burner, which supplies all the thermal load because no other heating system is selected by the optimization. [less ▲]

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See detailCritical Life: Bergson, Canguilhem and the Critical Investigation of Life and the Living
Wong, Tai Tak Andy ULg

Doctoral thesis (2016)

The objective of my research is to offer a critical investigation of life and the living according to Bergson and Canguilhem. The ‘critical’ perspective in this investigation refers to the exploration of ... [more ▼]

The objective of my research is to offer a critical investigation of life and the living according to Bergson and Canguilhem. The ‘critical’ perspective in this investigation refers to the exploration of the difficulty, controversy and significance of the problematic concept of life in these two different forms of philosophy of life. For Bergson and Canguilhem, it is life that generates questions about knowledge of life and the living. Although Bergson and Canguilhem develop their metaphysical and epistemological approaches of life respectively, they both stand for the reciprocity between life and knowledge. Throughout this critical investigation of their philosophies of life, I would argue that there is continuity between Bergson and Canguilhem on their reflections of the knowledge and thought of life. However, thus far, there has been no recent research that has concentrated on this discussion and clarified the difference between them. This investigation, for this reason, is an attempt to understand the concept of life according to Bergson and Canguilhem from a critical perspective. [less ▲]

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See detailPerformance and Robustness of Nonlinear Systems Using Bifurcation Analysis
Detroux, Thibaut ULg

Doctoral thesis (2016)

Nonlinear vibrations can be frequently encountered in engineering applications, and take their origin from different sources including contact, friction or large displacements. Other manifestations of ... [more ▼]

Nonlinear vibrations can be frequently encountered in engineering applications, and take their origin from different sources including contact, friction or large displacements. Other manifestations of nonlinearities are peculiar phenomena such as amplitude jumps, quasi-periodic oscillations and isolated response curves. These phenomena are closely related to the presence of bifurcations in the frequency response, which dictate the system's dynamics. While recent progress has been achieved to develop tools for nonlinear modal analysis of industrial applications, bifurcation analysis was still limited to reduced models and academic case studies. Along with the lack of an efficient algorithm to detect and study bifurcations, bifurcation analysis for design purposes also remained unexplored. The fundamental contribution of this doctoral thesis is the development of a new methodology for the detection, characterization and tracking of bifurcations of large-scale mechanical systems. To this end, an extension of the harmonic balance (HB) method is proposed. Taking advantage of the efficiency of the HB method for the continuation of nonlinear normal modes and frequency responses, this extension allows for robust computation of bifurcation curves in the system's parameter space. A validation of the methodology is performed on the strongly nonlinear model of an Airbus Defence & Space spacecraft, which possesses an impact-type nonlinear device consisting of multiple mechanical stops limiting the motion of an inertia wheel mounted on an elastomeric interface. The second main contribution is the development of a new vibration absorber, the nonlinear tuned vibration absorber (NLTVA), which generalizes Den Hartog's equal-peak method to nonlinear systems. The absorber is demonstrated to exhibit unprecedented performance for the mitigation of nonlinear resonances. In a second step, the HB-based bifurcation methodology is utilized to characterize the performance regions of the NLTVA, and to ensure its robustness with respect to parameter uncertainties. [less ▲]

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See detailÉtude des anthocyanes de l’Hibiscus sp
Beye, Cheikh ULg

Doctoral thesis (2016)

Très répandues dans le règne végétal, les anthocyanes sont le sujet d'un grand nombre d'études. Celles-ci abordent en général les aspects concernant leur instabilité vis-à-vis des conditions dans ... [more ▼]

Très répandues dans le règne végétal, les anthocyanes sont le sujet d'un grand nombre d'études. Celles-ci abordent en général les aspects concernant leur instabilité vis-à-vis des conditions dans lesquelles elles sont employées ou l'effet bénéfique de leur consommation sur certaines pathologies chroniques. Provenant de nombreux types de fruits et légumes comestibles, elles sont extraites en vue de leur utilisation comme colorant alimentaire naturel. C'est ce dernier aspect qui a été le sujet principal de ce travail dont l'objectif était de montrer que les calices d’Hibiscus sabdariffa (H. sabdariffa) pouvaient être utilisés comme matière première pour la fabrication de colorant. Les deux principaux cultivars provenant du Sénégal présentent des différences significatives du point de vue de leur contenu en anthocyanes sur le plan qualitatif et quantitatif. L'influence des conditions de culture sur la concentration en anthocyanes a été mise en évidence. Une technique chromatographique a été utilisée pour concentrer les anthocyanes. Les résultats provenant d'expériences faites en batch agité avec une résine macroporeuse ont permis de déterminer les paramètres tels que le temps de contact nécessaire à l'atteinte de l'équilibre, la capacité d'adsorption maximale et de conclure que la résine utilisée avait une capacité d'adsorption élevée pour les anthocyanes. Suite à la fabrication du colorant, une partie importante de la masse de calices restait inutilisée alors qu'elle contenait encore des substances valorisables. Leur caractérisation a permis de montrer que les résidus des calices d'H. sabdariffa pourraient être valorisés par la production de pectines destinées au marché des additifs alimentaires, d'oligosaccharides à effet prébiotique ou de biocarburants. [less ▲]

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See detailLe macrobenthos de substrats meubles en zone infralittorale Corse - Indice et méthodologie adaptée pour un diagnostic écologique facilité
Donnay, Annick ULg

Doctoral thesis (2016)

At the time where the safeguarding and the conservation of the environment are a need for the Man, various ecological quality indicators are currently followed to evaluate the human influences; among ... [more ▼]

At the time where the safeguarding and the conservation of the environment are a need for the Man, various ecological quality indicators are currently followed to evaluate the human influences; among those the soft-bottom macrofauna. On the basis of some of their characteristics, the calculation of various biotic indices makes possible to qualify the meadow. However, before this qualification, the analysis of the macrobenthos is long and tedious. Two problems involved in their study exist: 1. In Corsica, the classically calculated biotic indices do not give an account of the existence of impacted settlements in oligotrophic coastal area and subjected to weak human influences. 2. The length of their study related to the difficulty of identification prevented a prompt response to the decision makers. To solve these problems, the adaptation of the calculation of a biotic index to the Corsican environmental conditions as well as the means of limiting the length of studies of the soft-bottom macrobenthos is required. For the adaptation of an index and to give an account of the natural variability of the settlements, eight habitats linked with settlements were defined around Corsica. Then, the J’MAMBI, based on the polluo-sensitivity of species, the richness, the diversity of the settlements and their equitability was developed, with references of good and bad ecological conditions for each habitats type. The application of this index makes possible to highlight fine variations in ecological qualities. To facilitate the identification and to decrease the time of soft-bottom macrobenthos’ study, the principle of taxonomic sufficiency is applied to the J’MAMBI. This principle makes possible to bring to the decision makers and to managers of such environmental studies, a facility diagnosis and a prompt response. Around the island, the identification at the "family" level is sufficient to give an account of ecological quality definite by a work to the "species" level. Thanks to "Benthic Methodology Simplification" or BeMSi, coupling the J’MAMBI and the facilitated identification, the two posed problems were solved. The utility of this methodology was put ahead within the framework of fish-farming survey, of outfall survey, of bay survey. Its sensitivity is also sufficient compared to other indices based on other indicators like the posidonia. Thank to this study, two types of research are possible: • The fundamental research grouping the "species" level identification and the J’MAMBI in order to improve the specific knowledge of microbenthic settlements and their reaction under or without disturbances. • The applied research using the BeMSi in order to obtain a general overview of the ecological quality status of an area and to help with decision making. In the future, it would be interesting to apply the results of this thesis to long temporal series of data and to other geographical areas in order to confirm the robustness of the index and the methodology developed. [less ▲]

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See detailRéseau de copies artistiques autour de la tombe de Pahéry d'Elkab
Devillers, Alisée ULg

Master's dissertation (2016)

Il s'agissait, à travers ce mémoire de fin de master, de s'intéresser à la question de l’artiste en Égypte antique en abordant le cas de Pahéry d'Elkab, qui s’est représenté en tant que peintre (« sS-qd » ... [more ▼]

Il s'agissait, à travers ce mémoire de fin de master, de s'intéresser à la question de l’artiste en Égypte antique en abordant le cas de Pahéry d'Elkab, qui s’est représenté en tant que peintre (« sS-qd ») et chef des travaux dans la tombe de son grand-père, le héros de guerre Ahmose fils d’Abana (EK - pour Elkab - 5), et qui, par la suite, est devenu gouverneur d’Elkab et d’Esna, soit une carrière peu banale pour un artiste. Grâce à son statut de nomarque, Pahéry a pu faire réaliser sa propre tombe, qui porte de multiples traces de son ancienne activité professionnelle de peintre. Cette chapelle funéraire, la EK 3, se trouve au centre d’un réseau de copies artistiques suffisamment bien documenté que pour permettre de retracer avec précision la transmission de motifs iconographiques et textuels d’une tombe à l’autre. Cette thématique des copies, qui a servi de base documentaire pour aborder une véritable individualité artistique fut par ailleurs l’occasion de proposer une brève comparaison transculturelle entre l’ère pharaonique et la Renaissance italienne. La tombe de Pahéry d’Elkab a, dans un premier temps, été décrite et analysée, en cherchant à déterminer la situation chronologique, la carrière et la généalogie de son propriétaire. Différents termes et concepts relatifs au processus de « copie » ont ensuite été définis, avec une attention particulière à la « copie d’invention » – ou emprunt créatif, – un procédé essentiel pour comprendre la conception égyptienne de la notion de « créativité ». Ensuite, ont été envisagées tour à tour les tombes d’Ahmose, fils d’Abana (EK 5) et d’Ounsou (TT A4), toutes deux vraisemblablement réalisées par Pahéry lui-même. La tombe TT A4, située dans la nécropole thébaine mais dont on a aujourd’hui perdu la localisation précise, bien que certains fragments en soient aujourd’hui conservés au Musée du Louvre, s’est avérée particulièrement intéressante dans la mesure où son analyse permet de suggérer que Pahéry a réutilisé pour son propre monument funéraire des éléments iconographiques et textuels qu’il avait précédemment mis au point dans l’exercice de son ancienne profession de « sS-qd », dans la tombe d’Ounsou. Dans un troisième temps, ce sont les tombes voisines de Sétaou, chef des prêtres de Nekhbet qui a commandité une version du programme iconographique de la EK 3 remise au goût du jour de l’époque ramesside, et de Réneny, ancien gouverneur d’Elkab, qui ont été abordées. En reprenant l’organisation générale et le concept des scènes agricoles de cette dernière chapelle et en utilisant la forme monocamérale traditionnelle des tombes de l’antique Nekheb (actuelle Elkab), Pahéry s’est volontairement intégré dans le paysage monumental et historique de la nécropole d’Elkab. En guise de conclusion, l’analyse comparée des différentes modalités de copies observées, ainsi que de leurs motivations, a été replacée dans le cadre conceptuel de l’« intericonicité », récemment introduit en Égyptologie, afin de dépasser les limites et les connotations – souvent négatives et restrictives – de la notion habituelle de « copie ». La personnalité singulière de Pahéry d’Elkab a en outre été comparée à celle de Giorgio Vasari, un autre artiste – certes nettement plus récent – qui eut également à cœur de mettre en scène son individualité dans un monument destiné à sa postérité et à sa commémoration. A cet égard, la comparaison avec la Renaissance, une époque qui vit tout à la fois un recours très important au processus de la copie et le développement – ou à tout le moins le renouvellement – d’un véritable statut de l’artiste, s’est déjà révélée très stimulante et éclairante pour étudier un cas issu de l’Égypte antique. [less ▲]

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See detailCaractérisation de la niche édaphique des espèces cupro-cobalticoles du katanga (R.D. Congo) en vue de leur conservation et de leur valorisation dans des stratégies de phytostabilisation
Boisson, Sylvain ULg

Doctoral thesis (2016)

Natural metalliferous habitats represent unique study cases for scientific research as geopedology, biology and eco-evolution of metallophytes. Southeastern Democratic Republic of Congo hosts among the ... [more ▼]

Natural metalliferous habitats represent unique study cases for scientific research as geopedology, biology and eco-evolution of metallophytes. Southeastern Democratic Republic of Congo hosts among the most important copper and cobalt deposits of the world, having a high economic value. Copper and cobalt outcroups have been formed during billion years by geological successions. More than one hundred hills are now scattered in an area of 300 km long and 50 km large in vegetation matrix consisting on an open forest called Miombo. This area is called Katangan Copperbelt. At the top of hills, the close proximity between the deposit and the soil surface lead to a high concentration of bioavailable copper and cobalt in soil solution exceeding the tolerance threshold of most of plants. More than 550 taxa including 10 % are identified as endemics and compose two distinct herbaceous plant formations: the steppic savanna is found on the lowest minralised soils and the steppe occurs in the highest mineralized soils at the top of hills. Mining activities have dramatic consequences on environement and public health, leading to the destruction of natural meatlliferous habitats and to the creation of anthropogenic polluted sites. Considering the threat on endemic plant species of the Katangan Copperbelt, several in situ and ex situ conservation strategies have been implemented for the last ten years in collaboration with several institutions. Furthermore, metallophytes constitute remarkable resources for the biotechnologies such as phytoremediation due to their metal tolerance or their accumulation ability. Anthropogenic metalliferous sites of the Katangan Copperbelt could be considered for the conservation of metallophyte with a perspective of remediation of polluted soils. Both challenges require the characterization of the environmental factors determining the distribution of plant species in natural sites and their performance in anthropogenic sites. This thesis aims at characterising the edaphic niche of metallophytes from the Katangan Copperbelt in order to propose actions combining the conservation of metallophyte and the phytostabilisation of polluted soils. The first axis focused on the study of two fundamental concepts in ecology, the theory of ecological niche and the concept of edaphic endemism, in order to understand the plant-soil relationships. Threatened endemic species were chosen as study case to determine the cause of the restricted distributions of metallophytes on metalliferous soils. The second axis tested the success of the establishment of endemic metallophytes in phytostabilisation strategies using the grass Microchloa altera. An assessment of the potential of other grasses was performed based on the specific criterions needed in phytostabilisation in order to identify candidate species for conservation–phystabilisation strategies. [less ▲]

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See detailShallow geothermal energy: effect of in-situ conditions on borehole heat exchanger design and performance
Radioti, Georgia ULg

Doctoral thesis (2016)

The in-situ conditions are critical for the performance of Borehole Heat Exchangers (BHEs). However, in practice they are often not adequately considered, overwhelming the potential of these systems. This ... [more ▼]

The in-situ conditions are critical for the performance of Borehole Heat Exchangers (BHEs). However, in practice they are often not adequately considered, overwhelming the potential of these systems. This thesis focuses on the accurate estimation of the in-situ characteristics and on their influence on the design and the behaviour of BHEs based on an in-situ study of an heterogeneous bedrock in a semi-urban environment (campus of the University of Liege, Liege, Belgium). The experimental site consists of four double-U BHEs, of about 100 m long, installed over a surface area of 32 m² and equipped with fiber optic cables. Several temperature measurements and Distributed Thermal Response Tests (DTRTs) were conducted in situ in a period of four years, including a long-duration DTRT (heating phase of 7 months), during which temperature was measured by the fiber optics in all the four boreholes. These measurements create a unique data set, that allows to investigate the BHE behaviour for longer heating periods, to study the effect of various factors on the temperature field evolution at the heterogeneous bedrock at the in-situ scale and to evaluate the contribution of temperature borehole logging to the optimisation of BHEs. The effect of urbanisation is studied based on the in-situ measurements and on 3D numerical modelling and its influence on the design is expressed in terms of the maximum extracted power. The subsurface characteristics are correlated with the measured fiber optic profiles and the potential of temperature borehole logging for optimising the design of BHEs in practise is presented. The accuracy of the thermal response test results in the case of insufficient test rig insulation is investigated and recommendations are provided regarding the interpretation of the data by the widely applied Infinite Line Source model. The in-situ measurements during the long-duration DTRT are presented and analysed, together with a 3D numerical model of the test. In this case-study, the possible variation of the effective thermal conductivity along the layers and the air temperature variations during the test do not seem to have a dominant effect on the BHE behaviour during the whole heating phase. The controlling factors for the temperature field evolution in the surrounding rock mass (bedrock heterogeneity, the air temperature variations, the distance to the heating source and the thermal effects at the borehole bottom end) are detected in the measured profiles and their influence is discussed. [less ▲]

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See detailContribution to the study of african swine fever in the Democratic Republic of Congo: epidemiological and virological approaches
Mulumba Mfumu Kazadi, Léopold ULg

Doctoral thesis (2015)

Les résultats de cette thèse sont présentés sous la forme d’un ensemble cohérent de quatre études. 1. – Caractérisation moléculaire des souches du virus de la peste porcine africaine (PPA) impliquées dans ... [more ▼]

Les résultats de cette thèse sont présentés sous la forme d’un ensemble cohérent de quatre études. 1. – Caractérisation moléculaire des souches du virus de la peste porcine africaine (PPA) impliquées dans la persistance de l’infection en Afrique centrale (République Démocratique du Congo, RDC). Entre 1997 et 2000, sur 350 prélèvements de sang et organes provenant des porcs apparemment sains, 73 porcs (20,8%) avaient les anticorps dirigés contre la peste porcine africaine (PPA). Au cours de la même enquête, des organes prélevés sur les carcasses des porcs provenant d’une ferme familiale avec des mortalités constatées ont permis la détection de l’ADN du virus de la PPA. La caractérisation du virus a permis d’établir une similarité génétique avec des souches d’Afrique de l’Ouest, notamment du Nigeria et du Ghana. 2. – Estimation de la prévalence de la peste porcine africaine en République Démocratique du Congo et évaluation de la sensibilité et de la spécificité de trois tests ELISA en condition de terrain. Une étude a été menée sur 495 porcs domestiques apparemment en bonne santé de la RDC afin de déterminer le niveau d’exposition au virus de la PPA sur la base de 3 tests ELISA utilisant respectivement comme antigène la protéine VP72 soit sous forme brute (CP72) ou soit sous forme recombinante (rp72) et la protéine p30 recombinante (rp30). En outre, une PCR ciblant la région conservée du gène B646L codant pour la protéine de capside VP72 a été utilisée afin de déterminer l'exposition en fonction du stade de l'infection virus de la PPA. La prévalence apparente (PA) calculée avec les tests ELISA variait de 10% (48/482) avec la RP30 à 22,3% (79/354) avec la rp72. Basé sur des résultats positifs reproduits au moins par deux tests de diagnostic, la PA globale a été estimé à 17% (55/328). Parmi 495 animaux testés par PCR, l’ADN du virus de la PPA a été détecté chez 7 animaux (1,4%), dont 5 porcs séropositifs. En outre, en considérant le test ELISA CP72 comme référence, la sensibilité et la spécificité relatives des tests ELISA rp72 et rp30 ont été estimées sur un sous-ensemble de 328 porcs pour lesquels les résultats à tous les tests étaient disponibles. Le test ELISA rp72 avait une sensibilité relative de 93,5% (IC à 95%: 82,1 à 98,6) et une spécificité relative de 88,0% (IC à 95%: 83,6 à 91,5). Le test ELISA rp30 avait une sensibilité relative de 34,8% (IC à 95%: 21,3 à 50,2) et une spécificité relative de 93,7% (IC à 95%: 89,7 à 95,9). La combinaison globale de la PCR et des trois tests ELISA a révélé que 62% des cas positifs avaient au moins un de leur résultat confirmé par un autre test. Le test ELISA rp72 peut être recommandé dans le dépistage à grande échelle de la maladie dans les zones endémiques de PPA en Afrique comme une alternative au test ELISA de CP72. En outre, le test ELISA de rp30 peut être recommandé pour la confirmation à tout stade de l'infection, y compris dans les plus précoces en parallèle avec la PCR. 3 – La caractérisation génétique des isolats du virus de la PPA impliquées dans les foyers en République Démocratique du Congo, entre 2005 et 2012, révèle une co-circulation de trois Génotypes : I, IX et XIV et 16 variants du virus. L’étude a portée sur 62 pièces anatomiques de rates, ganglions hépato-gastriques, reins, cœurs, poumons, foies et estomacs provenant des 57 carcasses des porcs dont 54 provenant de foyers et 3 provenant des points d’abattage des marchés. L’ensemble représente 25 foyers au total. Ces foyers concernent 5 Provinces de la RDC, dont notamment l’Equateur, le Bas-Congo, le Katanga et Kinshasa. L’étude a révélé la co-circulation de 3 génotypes (I, IX et XIV) et 16 variants du virus. 4 - Immunisation des porcs des races Africaines avec le virus OURT88/3 du Génotype I induit une protection contre l’infection avec deux souches virulentes du Génotype I. La souche atténuée OURT88/3 du virus de la PPA, de genotype I, a déjà démontré son pouvoir protecteur chez les porcs domestiques de races européennes envers les isolats virulents du virus de la PPA. Pour déterminer si les réponses immunitaires protectrices pourraient également être induites chez des porcs de races indigènes de de la région Kinshassa en République démocratique du Congo, nous avons immunisé un groupe de 8 porcs avec la souche atténuée OURT88/3 et infecté les porcs 21 jours plus tard avec la souche virulente OURT88/1 du même génotype. Parmi les 8 porcs, 4 ont été protégés contre l’infection. Trois des 8 porcs sont morts du virus de la PPA et un 4ième est mort de cause inconnue. Les 4 porcs restants ont survécu à une seconde infection avec une souche virulente RDC 085/10 du virus de la PPA, de même génotype. Deux groupes contrôles de porcs non immunisés ont été infectés par la souche OURT88/1 ou la souche RDC 085/10 et ont développé des signes cliniques aigus de la PPA. Ils avaient des niveaux élevés de génome viral dans le sang. [less ▲]

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See detailEstimation of diet digestibility and intake by grazing ruminants through near infrared reflectance spectroscopy analysis of faeces. Application in various contexts of livestock production
Decruyenaere, Virginie ULg

Doctoral thesis (2015)

Grazing is the most economical feeding scheme for ruminants. Grazing management, however, is often difficult for breeders, particularly because of a lack of knowledge about grass availability and quality ... [more ▼]

Grazing is the most economical feeding scheme for ruminants. Grazing management, however, is often difficult for breeders, particularly because of a lack of knowledge about grass availability and quality. There are methods for assessing the quantitative and qualitative characteristics of grass, but they are difficult to apply in the case of grazing ruminants. Near infrared reflectance spectroscopy (NIRS) is based on the absorption of infrared light by organic matters to provide NIRS spectra. These NIRS spectra can be correlated with the chemical or biological composition of samples in order to develop calibrations that can be used as predictive models. The primary objective of this PhD thesis was to study the potential of NIRS applied to faeces (FNIRS) in order to predict the characteristics of the diets of grazing herbivores. The particular focus was on the in vivo organic matter digestibility, voluntary intake and botanical composition of ingested diets. The main results of the study show that FNIRS has great portential for estimating in vivo digestibility and voluntary intake by grazing ruminants and that faeces are a good indicator of ingested diets. Based on both large or small and varied databases, the results suggest that FNIRS spectral libraries could be developed for characterising ruminant feed intake. The accuracy of the FNIRS models in estimating in vivo digestibility and voluntary intake is similar to or better than that of other methods usually used to assess these parameters. FNIRS could also be used to predict ruminants’ diet composition in terms of plant species. These predictions should be used only for ranking, however, because of the current lack of accurate procedures for determining diet selection individually. NIRS applied to faeces can be used to predict the in vivo characteristics of forage with sufficient accuracy. The prediction error of NIRS calibrations depends on the accuracy and precision of the reference data. The prediction of in vivo digestibility and intake is sufficiently repeatable compared with the procedure using the reference method. Intake is more difficult to predict with sufficient precision and is more closely linked to animal variability and to uncertainty of the FNIRS models. The major difficulty in using this method lies in generating the diet-faecal pairs as reliably as possible. FNIRS calibrations for predicting in vivo diet characteristics are derivative calibrations. The sample analysed for reference values (diet samples) differs from the samples submitted to NIRS analyses (faeces). With regard to research on forages, in vivo trials with animals confined in pens or digestibility crates appears to be the best reference method for generating FNIRS calibrations. Future work will involve developing FNIRS calibrations for predicting independent datasets and using them to create decision-support tools for improving diverse grazing management schemes. The major focus should be to compare different feeding strategies rather than to obtain an exact estimate of feed intake values. As a low-cost and rapid prediction technique, FNIRS could contribute significantly to the development of a methodology that would help improve our knowledge of forage and animal variability. [less ▲]

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See detailScène d'énonciation et posture d'auteur: la mise en scène de soi dans la critique littéraire de Baudelaire
Mogollon Zapata, Juan Manuel ULg

Doctoral thesis (2015)

Il y aurait un Baudelaire réaliste, un décadent, un classique, un catholique, un révolutionnaire, un réactionnaire et même un postmoderne. Les images attribuées à l’auteur se superposent selon l’époque ... [more ▼]

Il y aurait un Baudelaire réaliste, un décadent, un classique, un catholique, un révolutionnaire, un réactionnaire et même un postmoderne. Les images attribuées à l’auteur se superposent selon l’époque, le lieu et les courants esthétiques et politiques dans lesquels il a été lu. Mais quelle image Baudelaire construit-il de lui-même dans ses textes critiques ? Comment s’y présente-t-il à son public ? Pour mieux cerner le visage littéraire de cette figure changeante et paradoxale, l’étude proposée ici cherche à démontrer qu’il existe bel et bien dans la critique littéraire de Baudelaire un travail de mise en scène de soi qui ne peut se comprendre qu’à partir des diverses scènes d’énonciation que le poète-critique a capitalisées tout au long de sa carrière. Cela soulève la question de la relation entre, d’un côté, la présentation de soi et la scène de parole dans laquelle elle s’inscrit et qu’elle aide à construire, et de l’autre, entre cette mise en scène discursive de soi et les stratégies de positionnement de l’auteur à l’intérieur du champ littéraire. Dans quelle mesure ce travail de présentation de soi est-il redevable de la "situation de discours" dans laquelle il s’énonce ? Et, corollairement, dans quelle mesure relève-t-il d’une stratégie de positionnement littéraire ? Dès que l’on constate que le choix d’une posture, ou de diverses postures au fil du temps, est à la fois lié à une scène d’énonciation, à une étape socioprofessionnelle et à un répertoire de rôles et de modèles prêts à être investis, on entre dans la logique de construction d’une œuvre, mais aussi d’une identité littéraire. [less ▲]

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See detailTranscriptomic analysis of pancreatic cells in zebrafish
Tarifeño Saldivia, Estefanía ULg

Doctoral thesis (2015)

Pancreas is a mixed gland composed of endocrine and exocrine tissues and plays a crucial role in the metabolism of all vertebrates. The endocrine cells are mainly grouped into the islets of Langerhans and ... [more ▼]

Pancreas is a mixed gland composed of endocrine and exocrine tissues and plays a crucial role in the metabolism of all vertebrates. The endocrine cells are mainly grouped into the islets of Langerhans and secrete distinct hormones, such as glucagon (α-cell), insulin (β-cell), somatostatin (δ-cell) and ghrelin (ε-cell). Diabetes occurs when insulin production by the β-cells is unable to counteract increase of glycemia. The goal of the first part of my thesis was to determine the transcriptomic signatures of each pancreatic cell type in zebrafish in order to identify novel cell type-specific regulatory genes that might be crucial for their differentiation and/or physiology. Pancreatic acinar cells, ductal cells as well as the endocrine α-, β- and δ-cells were isolated from different transgenic adult zebrafish using FACS and RNA-seq was performed from these highly purified cell types. Comparison between the RNA-seq datasets allowed us to highlight all genes (protein coding and non-coding genes) with enriched expression in each cell type and to identify new markers of the mature pancreatic cells in zebrafish. In order to establish the expression blueprint of pancreatic endocrine and exocrine cells conserved from fish to mammals, we compared the pancreatic transcriptomes from zebrafish, mouse and human. Using pancreatic RNA-seq data available in databases, we determined the set of genes displaying enriched expression in endocrine and exocrine cells of human and mouse. Comparison of these data with the zebrafish pancreatic endocrine and exocrine data revealed the genes with conserved expression among vertebrates. Most of the transcription factors previously known to be important for pancreatic cell differentiation are included in this set of conserved genes. This interspecies comparative analysis highlighted genes with evolutionary conserved expression whose pancreatic function is still unknown, but also revealed striking differences in gene expression patterns between species. The goal of the second part of my thesis was to understand the global transcriptional change produced by the loss-of-function of pax6b in pancreatic endocrine cells during pancreas development in zebrafish. We performed RNA-seq from purified pancreatic endocrine cells from wild-type and mutant (pax6b sa0086 null allele) zebrafish embryos at 27 hpf. By comparing the transcriptome of wild-type and mutant endocrine cells, we identified thousands of genes differentially expressed. Notably, we observed that the expression level of the pancreatic hormones was affected as it was reported in murine models. These analyses have revealed the transcriptional network regulated by pax6b in endocrine cells during differentiation. These analyses highlighted many unknown pax6b targets and novel regulators possibly involved in pancreatic function. Future functional analyses will be needed to further investigate the function of the novel regulators identified by this study. [less ▲]

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See detailLe vécu des femmes magistrates en Belgique francophone. Analyse d'une profession sous l'angle des rapports sociaux de sexe. Représentativité, profils et pouvoir
Cornet, Adeline ULg

Doctoral thesis (2015)

Sachant qu’historiquement l’exercice de la Justice a été réservé aux hommes, et que les femmes n'ont accès, en Belgique, que depuis un peu moins de 70 ans à la magistrature ; la question centrale de cette ... [more ▼]

Sachant qu’historiquement l’exercice de la Justice a été réservé aux hommes, et que les femmes n'ont accès, en Belgique, que depuis un peu moins de 70 ans à la magistrature ; la question centrale de cette recherche doctorale s’attache à étudier l’impact de l’arrivée des femmes dans la magistrature et de leur exercice de cette fonction régalienne et de pouvoir, ainsi que de leur vécu personnel et professionnel. Choix a été fait d’aborder cette question centrale suivant une méthodologie qualitative et l’utilisation de récits de vie ; et les résultats obtenus y répondent à travers trois grands axes analytiques pouvant être résumés en trois questions : 1/ Combien sont ces magistrates et « où sont-elles » ? Quelle a été l'évolution numérique des femmes dans la magistrature au cours du temps ? Quels postes et quelles fonctions occupent-elles ? 2/ Qui sont les magistrates et comment se définissent-elles ? Quels sont leurs profils et leurs trajectoires professionnelles ? Quel sens, quelles significations donnent les magistrates à leur profession et à la place qu'elle tient dans leur vie ? Quel est leur vécu ? 3/ Quelle vision ont les magistrates du pouvoir ? Et comment se positionnent-elles face à cet attribut central de leur profession ? Ces analyses, réalisées à travers la comparaison des parcours et vécus des quarante-neuf magistrates interrogées, se veulent être une première étude de genre de cette profession visant à connaître qui sont ces magistrates, la place qu'elles occupent dans la profession, la manière dont elles l'envisagent et lui donnent sens. [less ▲]

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See detailEcologie et connaissances ethnozoologiques de quelques espèces d'oiseaux gibiers menaces des ecosytèmes du Sud du Bénin
Lougbegnon, Olou Toussaint ULg

Doctoral thesis (2015)

The natural areas of the south of Benin under subequatorial climate are diversified in resident birds’ species as well as migratory one. Some of them are hunted for food and therapeutic purposes by ... [more ▼]

The natural areas of the south of Benin under subequatorial climate are diversified in resident birds’ species as well as migratory one. Some of them are hunted for food and therapeutic purposes by grassroots communities. The most used are Guttera pucherani, Dendrocygna viduata, Egretta alba, Egretta ardesiaca, Porphyrio alleni et Porphyrio porphyrio. In order to reduce pressure on biodiversity in this part of Benin and to implement the sustainable conservation of birds’ species, this study on ecology and ethno-zoological knowledge of hunted bird species was carried out in the forest areas and the Ramsar sites 1017 and 1018. Field prospections were conducted from 2009 to 2012. The birds’ inventory method used was based on listening point techniques of 15 minutes. Data analysis were analyzed through the computation of bird species abundances, the establishment of maps distribution of the species, the habitat description and the modeling of the climatic niche of these species under climatic models CCCMA (Canadian Centre for Climate Modeling and Analysis) and CSIRO (Commonwealth Scientific and Industrial Research Organization) using MAXENT3.3.2. The ethno-zoological knowledge of the birds species were assessed through individual and groups survey and allowed to calculate the use values of the different part of the birds’ species according to the socio-cultural groups, sex and age. Moreover a logistic binary regression was carried out to determine the socio-economic factors which affect bird species exploitation by the grassroots communities. Results of modeling showed that among the variables selected for the prediction of the climatic models, distance from river, altitude appeared as the environmental variable which more contributed to the prediction of the models (with an average of 74.32 % and 12.94%). Projection under CCCMA and CSIRO in 2050, showed a progression of the favorable areas to Dendrocygna viduata, Porphyrio alleni, Porphyrio alleni, Egretta ardesiaca while it showed a regression of the favorable areas to Egretta alba. The estimated uses values showed that the ethno-zoological knowledge on the bird species differed according to the ethnic groups. Birds are used for food, medicinal and magico-mystics purposes. The magico-mystics and food were the most frequent used categories. Homogeneity of knowledge was found among the informants regarding the ethnic group as well as for the sex with respectively 0.66 and 0.7 for the use diversity value (ID) and use equitability value (IE). No significant difference was found between the informant for the use diversity value (ID) and use equitability value (IE). This study helps to build a database on 6 birds’ species and can be used for bird game ranching and game farming in Benin. [less ▲]

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See detailLe financement de l’agriculture au Bénin : stratégies de gestion et d’adaptation des exploitations agricoles
Sossou, Comlan Hervé ULg

Doctoral thesis (2015)

Benin is highly dominated by agriculture: about 80 % of the population are rural and involved in farming activities. The challenge now is to create suitable conditions for the improvement and ... [more ▼]

Benin is highly dominated by agriculture: about 80 % of the population are rural and involved in farming activities. The challenge now is to create suitable conditions for the improvement and competitiveness of farming systems and the creation of small and medium enterprises along the different chains of agricultural value. One such challenge involves facilitating the access of farmers and other stakeholders, to input markets, products and especially financial services. This highlights the need to establish an optimal framework for financing agricultural activities based on lessons learned from current experiences and using the best recent institutional innovations in the field. This thesis focuses on the issue of funding for agriculture and strategies developed by producers and other stakeholders including the public sector. To understand agricultural activities financing problems in rural areas, a research was conducted from 2010 to 2014. The research targets are farms and their access to financial services. A survey of 475 farms was conducted in 2011. In 2014, a deepening phase was performed on 40 farms. Research results revealed that financial needs of farms are not totally satisfied. The loans granted are small amounts, mostly. Productive investments that constitute investments in medium and long term, which can lead to significant improvements in agricultural production, are almost unsatisfied. Moreover, analysis showed that income determines access to credit. This factor reflects to a certain level the ability of farmers to provide the financial guarantees required by microfinance institutions. Also, producer's ability to invest and to provide the required guarantees, his loyalty and compliance with the rules of microfinance institutions (MFIs) facilitate access to high loan amounts. Analysis also showed that credit rationing affects a large number of producers. The consequence of this rationing is the reduction in agricultural inputs use, in hired labour, in acreage, etc. And therefore, decrease in yields and producers incomes. In summary, current conditions offered by microfinance institutions is not conducive to agricultural development and livelihoods improvement of rural populations. It is therefore necessary to rethink agricultural activities funding and develop a sustainable financing mechanism for both producers and funding agencies. To this end, the initiative for the establishment of a National Fund for Agricultural Development (NFAD) should be accelerated to allow farmers easier access to credit and adequate. [less ▲]

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See detailEtude des principes supranationaux de prévention des conflits armés - Exemple du système éducatif primaire de Prishtina (Kosovo)
Pierre, Alexia ULg

Doctoral thesis (2015)

The Unmik, United Nations Mission in Kosovo, was launched in the aftermath of mass violations of War Law and of International Humanitarian Law, perpetrated by the Republika Srpska against the Albanian ... [more ▼]

The Unmik, United Nations Mission in Kosovo, was launched in the aftermath of mass violations of War Law and of International Humanitarian Law, perpetrated by the Republika Srpska against the Albanian civilian of Kosovo. The Unmik was mandated to prevent the interethnic violence and to neutralise the roots of conflict, and to let emerge a new society where intercommunity antagonisms do not exist anymore. The mass education appears to be a tool that leads to a sustainable development of society. Therefore, the International Community links education and conflict prevention due to the role of education in social integration and development, and through specific contents. The supranational principles of education to conflict prevention are framed by an international framework, mostly developed in the nineties. Finally, education was at stake and was instrumentalised by the nationalist propagandas during the conflict between Serbs and Albanian in Kosovo. The main object of this research is to explore the way these principles of education to conflict prevention are operationalized in the primary public education system in Kosovo, through the study case of the main city Prishtina. The premise is that the operationalization can carry some boundaries to the complete expression of these supranational principles. The first step was dedicated to the research of the supranational principles in a normative and legislative corpus of local texts. The second step was a study of the expression of the principles of prevention in the primary public schools of Prishtina and with some members of the education system of Kosovo. This work highlights the sustainability of the operationalized principles on the formal and structural stages, due to the integration in the local normative and legislative frame. However, the operationalization can lead to an incomplete or a limited expression of the principles of an education involved in the conflict prevention. The top down approach of the Unmik and its lack of practical application of the principles are important elements in the limited expression of these principles. The boundaries are linked to the failure in questioning the education model applied in Kosovo as well, and to the assumptions it carries. Finally, the inadequate support to the educational staff and the inadequacy of this education model to the specificities of Kosovo are equally major factors of the limited operationalization of the supranational principles of conflict prevention in the primary schools of Prishtina. [less ▲]

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See detailEtude des apports de l'épidémiologie participative à l'évaluation des systèmes de surveillance en santé animale
Calba, Clémentine ULg

Doctoral thesis (2015)

Les systèmes de surveillance en santé animale sont mis en place dans le but de répondre à des enjeux de santé publique et de santé animale, ils permettent également de limiter les pertes économiques et de ... [more ▼]

Les systèmes de surveillance en santé animale sont mis en place dans le but de répondre à des enjeux de santé publique et de santé animale, ils permettent également de limiter les pertes économiques et de préserver la biodiversité. Du fait de l’importance capitale de ces systèmes tant au niveau national qu’international, il est fondamental de mettre en place des évaluations régulières et pertinentes afin de s’assurer de leurs performances, mais également dans le but de déterminer si les ressources fournies sont utilisées de manière optimale. Différents guides ont été développés afin d’accompagner les évaluateurs dans cette démarche, en santé animale tout comme en santé humaine, décrivant avec plus ou moins de détails comment identifier et mesurer les différents attributs d’évaluation (e.g. sensibilité, représentativité). Les processus d’évaluation proposés et actuellement appliqués présentent cependant certaines limites, telles qu’un manque de flexibilité dans la prise en compte du contexte, et la faible prise en considération des aspects socio-économiques de la surveillance. Pour pallier ces manques, il a été proposé d’utiliser des approches participatives afin de déterminer les perceptions, attentes et besoins des différents acteurs impliqués dans la surveillance. L’objectif de ce travail de recherche était ainsi de déterminer l’apport de l’épidémiologie participative à l’évaluation des systèmes de surveillance en santé animale. Afin de déterminer les attributs d’évaluation pour lesquels la mise en place d’approches participatives peut apporter une valeur ajoutée, un travail de revue et d’analyse critique des méthodes actuellement utilisées pour leur mesure a été réalisé. Ce travail a permis d’identifier trois niveaux d’utilisation possibles de l’épidémiologie participative : (i) la mesure d’un attribut d’évaluation dans son ensemble, (ii) l’appui à la collecte de données nécessaires à l’estimation de l’attribut d’évaluation, et (iii) la collecte d’informations complémentaires permettant d’interpréter les résultats de l’évaluation. Pour ce travail, deux attributs ont été sélectionnés : l’acceptabilité, qui réfère à la volonté des acteurs de participer à la surveillance et pour lequel une méthodologie d’évaluation participative complète a été développée ; les bénéfices non-monétaires, qui réfèrent aux conséquences positives directes et indirectes produites par le système pour les utilisateurs et pour lequel une méthodologie de collecte de données nécessaires à son estimation a été développée. Ces méthodologies ont été appliquées dans deux études de cas : le système de surveillance de la peste porcine africaine en Corse (étude pilote), et le système de surveillance de la tuberculose bovine en Belgique. Ces travaux ont permis de mettre en avant la faisabilité d’utiliser des approches participatives dans des contextes développés, avec des acteurs variés tels que les éleveurs, les services vétérinaires ou encore les agents de laboratoires. Ils ont également permis d’aboutir à une méthodologie participative globale pour mesurer l’acceptabilité : « AccePT » (Acceptability Participatory Toolkit). Concernant les bénéfices non-monétaires, l’utilisation d’une méthode d’estimation contingente associée à un empilement proportionnel a permis d’identifier les informations sanitaires d’intérêt pour les éleveurs, et d’estimer la valeur économique de ces informations pour ces acteurs. Cependant, la méthode développée nécessite encore des ajustements. Faisant suite à ces différents travaux, les bénéfices liés à l’application de l’épidémiologie participative pour l’évaluation des systèmes de surveillance en santé animale ont pu être mis en avant. En effet, celle-ci permet de formuler des recommandations pour l’amélioration de la surveillance basées sur le contexte et prenant en considération les perceptions, attentes et besoins des différents acteurs impliqués. Par une implication directe des acteurs dans le processus d’évaluation au travers des entretiens ouverts, elle permet d’aboutir à une meilleure acceptabilité de celui-ci. Elle offre également l’opportunité de collecter des données complémentaires sur le contexte général dans lequel la surveillance est mise en place, sur le système ainsi que sur des attributs d’évaluation différents des attributs ciblés à l’origine, tels que l’offre de formation et la communication. Cette implication directe des acteurs aide également au renforcement du sentiment d’appartenance des parties prenantes au système de surveillance ciblé, ainsi qu’à une sensibilisation des acteurs vis-à-vis du fonctionnement de ce système et des maladies ciblées. Ces bénéfices sont malgré tout à contrebalancer avec les limites et biais de ces approches, tels que le temps nécessaire à la mise en place et à l’analyse des entretiens et la sélection des participants. L’application de méthodes et d’outils participatifs dans le cadre de la surveillance permet ainsi d’optimiser l’évaluation de ces systèmes. Cependant, leur intérêt dépendra fortement du contexte dans lequel les outils seront appliqués, ainsi que des contraintes liées au processus d’évaluation. [less ▲]

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