However, good prospects are seen to improve conditions in the rural uplands in the future. Thus, different strategies should be implemented to fill the gap and improve the position of farmers. The study derives helpful recommendations for farmers keeping beef cattle to strongly develop their production, alleviate poverty, and improve their livelihoods. [less ▲]Detailed reference viewed: 69 (24 ULg) auditory sensitivity in birds: sex differences and noise impactsNoirot, Isabelle Doctoral thesis (2011)Detailed reference viewed: 18 (7 ULg) Synthèse, mise en forme et frittage de céramiques thermoélectriques de formulation In2-xGexO3Combe, Emmanuel Doctoral thesis (2011)Ce travail de thèse porte sur l’étude des relations procédé, micro/nanostructures et propriétés thermoélectriques de composés oxydes de formulation In2-xGexO3. Dans ce contexte, des techniques de synthèse ... [more ▼]Ce travail de thèse porte sur l’étude des relations procédé, micro/nanostructures et propriétés thermoélectriques de composés oxydes de formulation In2-xGexO3. Dans ce contexte, des techniques de synthèse des poudres par chimie douce (procédé citrate), de mise en forme en milieu liquide (coulage en moule poreux) et de frittage non conventionnel des céramiques (frittage micro-ondes) ont été développées. Par comparaison à des procédés d’élaboration classiques, le développement du procédé citrate a permis la préparation de microstructures homogènes permettant d’optimiser les propriétés de transport. La figure de mérite ZT des composés In2-xGexO3 atteint ainsi des valeurs supérieures à 0,3 à 1000 K. Afin de mieux contrôler la densification pendant le frittage, l’utilisation d’une technique de mise en forme par coulage en moule poreux a été expérimentée et des densités après frittage proches de la densité théorique ont pu être obtenues grâce à une mise en ordre optimisée des particules dans les composés crus. Le développement du frittage micro-ondes à ce type de matériau a par ailleurs permis d’obtenir des microstructures très fines (taille de grains inferieure à 500 nm). Un dispositif thermoélectrique (surface de 35 × 40 mm², 56 jambes) de formulations Ca3Co4O9 et In1.994Sn0.006O3 a été également réalisé. Celui-ci délivre une puissance de 480 mW pour un gradient de température de 550 K. Ces différentes études ouvrent des perspectives intéressantes dans l’élaboration de composés et de dispositifs thermoélectriques à base d’éléments oxydes présentant des performances accrues. [less ▲]Detailed reference viewed: 56 (8 ULg) Etude des propriétés physico-chimiques et technofonctionnelles des crèmes végétales en relation avec les conditions de reconstitutionAnihouvi, Prudent Placide Doctoral thesis (2011)In this work, an integrated approach was adopted to study vegetal creams in order to have a global understanding of their properties. This approach included: (i) the influence of fat and other ingredients ... [more ▼]In this work, an integrated approach was adopted to study vegetal creams in order to have a global understanding of their properties. This approach included: (i) the influence of fat and other ingredients of the formulation, particularly a low molecular weight surfactant, Tween 60 (ii) and the manufacturing process implemented for their preparation. The effect of fat was investigated by adopting an original approach that consisted in studying both the thermal and structural behavior of the non-emulsified fat (NEF) and the emulsified fat (EF). This clearly demonstrated the impact of the physicochemical characteristics of fat on the physicochemical and technofunctional properties of creams. It well established that small differences in the composition of fats may have great effects on the technofunctional behavior of creams. The influence of fat on the final properties of creams was mainly marked through the crystallization and melting behaviors of fat, and through the crystalline varieties formed during maturation. The effect of temperature on the stability of creams based on the physical evolution of the fat was also highlighted. The addition of tween 60 to the formulation significantly improved the properties of particle size, rheology, stability and whipping of creams. This improvement was the result of not only synergistic effect of surfactant molecules of buttermilk and tween 60 during emulsification but also desorption of proteins from the drop surfaces and modification of crystallization of the EF. The study of the influence of the process showed that the choice of the emulsification method and operating parameters are important considerations in the reconstitution of creams. It was shown that it was possible to modulate the properties of creams by only modifying the process. [less ▲]Detailed reference viewed: 35 (9 ULg) Analytical strategies for the detection of counterfeit erectile dysfunction drugsSacré, Pierre-Yves Doctoral thesis (2011)Since the late eighties, when it was first mentioned, the worldwide phenomenon of pharmaceutical counterfeiting is growing. Belgian customs often encounter presumed counterfeited medical products in ... [more ▼]Since the late eighties, when it was first mentioned, the worldwide phenomenon of pharmaceutical counterfeiting is growing. Belgian customs often encounter presumed counterfeited medical products in Belgian airports and ports because of their central position in Europe and their importance in the transit of goods. Further and deeper analyses are required to assess the counterfeit character of these goods and to provide a scientific basis for the eventual legal procedure. As reference laboratory for the federal agency for medicines and health products (FAMHP), the Scientific Institute of Public Health (IPH) frequently analyses illegal and counterfeit pharmaceutical preparations. The present research project was started with the objective of evaluating several existing methods and developing new analytical methods to detect counterfeit erectile dysfunction drugs. This thesis is focused on the analysis of illegal samples of phosphodiesterase type 5 inhibitors (PDE5-i) containing drugs because these are the most counterfeited pharmaceutical specialities in Belgium. The research was divided into a spectroscopic and a chromatographic part: Infrared based spectroscopies have already demonstrated their ability to detect counterfeit drugs. The first part of the study evaluates the capacity of each technique (mid-infrared (mid-IR), near-infrared (NIR) and Raman spectroscopy) separately and their combinations to discriminate genuine from illegal tablets. Then, the Classification And Regression Trees (CART) algorithm has been used to classify the different samples following the classification system of the Dutch National Institute for Public Health and the Environment (RIVM). The second spectroscopic approach used Raman microspectroscopy mapping to detect counterfeited Viagra®. This technique allows the detection of different compounds according to their Raman spectrum but also the study of the distribution of a selected ingredient among the core of a tablet. The chromatographic part consists of the development and validation of a new Ultra High Pressure Liquid Chromatography method coupled with a UV diode array detector (UHPLC-DAD) and compatible with mass spectrometry (MS) to detect and quantify the three authorised phosphodiesterase type 5 inhibitors (sildenafil, tadalafil and vardenafil) and five of their analogues in illegal pharmaceutical preparations. This method has been validated between +/- 5% acceptance limits using the total error approach and has been compared to the official Viagra® assay method. The ability of HPLC-UV impurity fingerprints to detect illegal samples and to predict whether a new unknown sample is genuine has also been evaluated. The developed analytical methods may be included in a general approach to detect counterfeit drugs containing PDE5-i. This generic approach may also be used to detect other types of counterfeited drugs but should therefore be adapted for each type of medicine. [less ▲]Detailed reference viewed: 88 (7 ULg) Introduction à la démarche spirituelle des moines errants de l'Egypte copte (250-451). Une étude fondée sur la "Mission de Paphnuce" et les principales sources littéraires du monachisme errant de l'époque concernéeMalevez, Marc Doctoral thesis (2011)Having given the definition of the words "monks" and "wanderer", the thesis try to demonstrate that the spiritual step as it is presented by Evagrius Ponticus corresponding to the reality that was in the ... [more ▼]Having given the definition of the words "monks" and "wanderer", the thesis try to demonstrate that the spiritual step as it is presented by Evagrius Ponticus corresponding to the reality that was in the spirit of the wanderer monks in Coptic Egypt and not a philosophical construction, based mainly on his experience outside Egypt. We will reconstitute and put in order the essential anachoristic monastic step, since the renouncement of marriage and fatherhood until the final getting of the Charism of the perfect and a saint on earth, as it appears from the main literary sources of that era. The thesis is also based on three Coptic manuscripts, three Arabic Manuscripts and five Ethiopian Manuscripts of the "Mission of Paphnutius", a travel story written in the fourth century. The thesis demonstrates also the characteristic idiorrhytmic and without doubt essentially reasonable of the step of the monks. [less ▲]Detailed reference viewed: 37 (9 ULg) Utilisation des composts de biodéchets ménagers pour l'amélioration de la fertilité des sols acides de la province de Kinshasa (République Démocratique du Congo)Mulaji Kyela, Crispin Doctoral thesis (2011)This work is part of the research for appropriate methods for sustainable management of the sandy soils of the province of Kinshasa (Democratic Republic of Congo), in order to ensure and guarantee the ... [more ▼]This work is part of the research for appropriate methods for sustainable management of the sandy soils of the province of Kinshasa (Democratic Republic of Congo), in order to ensure and guarantee the adequate food security. It consists of a scientic research of the use of composts produced from household organic waste in improving the quality of sandy soils to the province of Kinshasa. The general objective pursued in this work is to evaluate the impact of four repeated applications of organic matter from bio-waste compost on chemical and biochemical parameters dynamics in acid sandy soils and their productivity. A pilot composting on a small scale has been installed for the production of composts from municipal solid waste and characterization of composts obtained has revealed the agronomic potential that presents this material. The diagnosis of the condition agropedological soils revealed that soils of the three study sites are sandy classified as rubics arenoferrasols (dystrics), have excellent physical conditions for drainage, air circulation and root penetration possess variables charges colloids, show an acid reaction, low organic matter and low nutrient minerals contents. In addition, their water and nutrients retentions capacity are very limited, and are the main soil constraints to agricultural productivity of these soils. After four growing seasons in real environments, the study of the reaction with the soil organic amendments (20, 40, 60 t.ha-1 MB) gave satisfactory results. The provision of continuous additions of organic composts significantly increased the values of pH, TOC, CEC, SB eff and reduced the rate of exchangeable Al saturation in the three sites. With the highest dose T3 (60 t.ha-1 MB), the pH increased at least 0.8 units and the carbon content multiplied by 2.5 to 3 on the three sites. CEC values increased from 3.3 to 5.02 cmol(+)mg.kg-1 and the toxic aluminum saturation decreased more effective than 90%. Regarding biochemical parameters (microbial carbon & nitrogen, RB, RIS, APA, Unt, Ut), compost treatments induced a significant improvement in function and doses applied throughout the experiment. These contributions have induced microbial activity which contributed to the increase in soil nutrients (N, P, ...) by microbiological activities. The availability of nutrients and fourniture of carbon by the composts explain these increases. In addition, yields on different test plants (Glycine max L. Merr, Arachis hypogaea L. and Hibiscus sabbariffa L.) were positively influenced by the treatments of organic composts household wastes. Compared with mineral fertilizers, their fertilizing potential is not negligible. According to the results observed, doses ≥ 40 t.ha MB-1 should be to keep and maintain an acceptable level of fertility and yields potentiel of crops. But low doses were more efficient than high doses of agronomic point of view. Doses ≤ 20 t.ha-1 MB are recommended in annual crop and regular. Phosphorus was found to be the most limiting element to agricultural production of soil sites studied whatever of the types of amendments and cultures used. Finally, the study indicates that for reasons of efficiency, availability and funds increased production may be obtained through synergy between the composts used in small quantities and fertilizer mineral supplements. [less ▲]Detailed reference viewed: 100 (9 ULg) Contribution of cobalt-mediated radical polymerization to macromolecular engineering and photodynamic therapyHurtgen, Marie Doctoral thesis (2011)Cobalt-mediated radical polymerization (CMRP) is an emerging class of controlled radical polymerization technique based on the reversible deactivation of the propagating radicals by a cobalt complex. This ... [more ▼]Cobalt-mediated radical polymerization (CMRP) is an emerging class of controlled radical polymerization technique based on the reversible deactivation of the propagating radicals by a cobalt complex. This thesis aims at broadening the nature, the structure, the properties and the end-use of (co)polymers accessible by CMRP. The first part of this work is devoted to the synthesis of novel statistical, graft and block copolymers by CMRP. First, the statistical copolymerization of conjugated (n-butyl acrylate) with a non-conjugated one (vinyl acetate) has been successfully controlled by bis(acetylacetonato)cobalt(II). The optimal experimental conditions were then implemented to the copolymerization of vinyl acetate with poly(ethylene glycol) acrylate, which yielded (quasi-)diblock amphiphilic graft copolymers for potential biomedical applications in one step. CMRP also revealed successful for the synthesis of well-defined thermo-responsive copolymers based on poly(N-vinylcaprolactam), either amphiphilic or double-hydrophilic at room temperature. In the second part of this thesis, we investigated the potential of CMRP for the synthesis of new agents for cancer photodynamic therapy. The synthesis of such photosensitizers relied on the chain-end functionalization by [60]fullerene of water-soluble (co)polymers (or precursors) prepared by CMRP. The photodynamic activity of poly(vinyl alcohol)/C60, poly(N-vinylpyrrolidone-co-vinyl acetate)/C60 and poly(PEG acrylate-co-vinyl acetate)/C60 nanohybrids were assessed through photophysical and in vitro experiments. Also, the ability of the nanohybrids to avoid recognition by the immune system was evaluated by a protein adsorption test. Finally, some hints on how to improve the synthesis of the nanohybrids - and therefore, their photodynamic activity - were provided by a mechanistic study of the grafting onto C60 of macroradicals released by cobalt end-capped polymers [less ▲]Detailed reference viewed: 98 (65 ULg) Une expérience critique de la pensée. Essai sur les kantismes de Foucault (1961-1969/1978-1984)Bolmain, Thomas Doctoral thesis (2011)Ma thèse se propose de démontrer les points suivants : 1. La pensée de Foucault doit être rapportée comme à sa condition de possibilité philosophique à l’émergence historique de la pensée critique telle ... [more ▼]Ma thèse se propose de démontrer les points suivants : 1. La pensée de Foucault doit être rapportée comme à sa condition de possibilité philosophique à l’émergence historique de la pensée critique telle qu’elle est associée au nom de Kant : j'ai étudié, dans leurs modalités diverses, « les kantismes de Foucault » ; 2. Pour le comprendre, il est de première importance de se concentrer sur les deux extrêmes de son parcours philosophique (1961-1969 et 1978-1984) ; 3. Ce postulat en implique un autre, de nature méthodologique : le choix de privilégier une reconstruction conceptuelle plutôt que chronologique de l’œuvre de Foucault ; ainsi peut-on mettre en évidence la cohérence très forte qui anime son parcours, sous les discontinuités évidentes qui l’affectent ; 4. La cohérence philosophique de la pensée de Foucault est liée à trois éléments : - l’unité d’une méthode, d’une certaine attitude de la pensée (nominalisme matérialiste réalisé dans la forme d’une archéo-généalogie) ; - l’insistance d’une question toujours posée dans le cadre de l’interrogation critique et d’une reprise partielle des motifs du transcendantal et surtout de la finitude ; cette question se résume du passage de la critique de la question anthropologique classique (Qu’est-ce que l’homme ?) à une enquête portant sur les modes d’être historiques du sujet (Que sommes-nous aujourd’hui ?) ; - la reprise constante de trois concepts qui font le cœur de la conceptualité philosophique moderne et qui forment chez Foucault un réseau à la relative systématicité : ceux d’expérience, de pensée et de critique ; 5. Le concept d’expérience est la pierre de touche de toute l’œuvre de Foucault : seule sa reconstruction patiente permet de saisir, de décrire et d’élaborer de manière satisfaisante la manière de penser qui est la sienne, dans son rapport critique à la pensée de Kant. Une fois rapportée à sa condition historique de possibilité, l'oeuvre de Kant, on comprend à la fois la nécessité conceptuelle de la proposition philosophique de Foucault mais aussi, par suite, les limites de sa proposition éthico-politique. C'est ce que j'ai nommé le nihilisme achevé ou positif de Foucault, la pure exigence d'une transformation micro-politique indéterminée et non-fondée de l'état de choses donné. Aller plus loin que celle-ci supposerait de reprendre la question philosophique directrice de Foucault - comment la transformation du sujet dans l’histoire vers un surcroît d’autonomie s’articule-t-elle à sa finitude radicale ? - aux abords de la dialectique, et en particulier en fonction de concepts critiqués par l'auteur, ceux de négativité et de totalité. [less ▲]Detailed reference viewed: 85 (24 ULg) Nanostructuration induced by self-organization of polystyrene nanospheres as a template for the controlled growth of functional materialsColson, Pierre Doctoral thesis (2011)In the last few years, nanosphere lithography emerged as an inexpensive, material specific and high-output nanostructure fabrication process to manufacture arrays of periodic structures. The goal of this ... [more ▼]In the last few years, nanosphere lithography emerged as an inexpensive, material specific and high-output nanostructure fabrication process to manufacture arrays of periodic structures. The goal of this thesis was centered on both parts of the nanosphere lithography process, namely first the optimization of monolayer colloidal masks prepared by spin coating of monodisperse polystyrene (PS) nanospheres and secondly the use of these masks to develop new attractive applications in various fields. In order to assess the quality of the manufactured colloidal crystal masks, we developed a computerized image analysis procedure (Matlab) based on SEM micrographs. We successfully performed the different stages of the image analysis in such a way to discriminate and identify each nanosphere. As a quantification of order in the self-organized nanospheres, we chose to determine the percentage of hexacoordinated nanospheres by computing the distances between each of them. We applied experimental design to spin coating to evaluate the efficiency of this method to extract and model the relationships between the experimental parameters and the degree of ordering in the particles monolayers. We identified adequate spin coating parameters to synthesize large defect-free domains, reaching up to 200 μm2, which is the highest value ever reported for samples prepared by spin coating. Statistical analysis highlighted that rapid substrate acceleration and high rotation rates are necessary to get large, well-ordered areas. We also studied the surfactant concentration usually added to the beads suspension or the use of reactive ion etching (RIE) process to modify the masks. By using PS nanosphere templates (490 nm or 250 nm diameter), we successfully manufactured large arrays of L10-Fe50Pt50 and Co nanotriangles with uniform sizes. In addition to crystallographic and microstructural characterizations, we evaluated the magnetic properties of the nanostructures both from a qualitative (MFM) and quantitative (SQUID) point of view. The magnetic stability of the single-domain FePt nanodots was evidenced by focused MOKE analysis. This is of major importance for further use in magnetic storage applications and has never been reported yet. The soft magnetic Co nanodots displayed either single domain or vortex domains states, depending on the magnetization direction. The MOKE hysteresis loops revealed an increased coercive field compared with thin films. This is probably due to a specific magnetization reversal process caused by the shape of the nanodots. Oxide nanostructures were then manufactured. The polystyrene templates (490 nm diameter) were used for the guided hydrothermal growth of well-aligned ZnO nanowires. The control of the spacing between the nanowires combined with high c-axis preferred orientation led to higher dye loading values compared with continuous unpatterned films. This was undoubtedly attributed to an increased accessible surface area due to the patterning. Moreover, the increased roughness due to the patterning induced a higher water contact angle compared with an unpatterned ZnO nanowire array. Reversible superhydrophylicity to hydrophobicity was observed and controlled by successive UV illumination and O2 annealing. The achievements attained in this work have brought a significant contribution to the field of nano- and microfabrication. New pathways were opened for interesting future work with respect to continued fundamental and applied research. [less ▲]Detailed reference viewed: 229 (46 ULg) Experimental and numerical study of the factors influencing the performances of magnetic screens made of high temperature superconductorsFagnard, Jean-François Doctoral thesis (2011)In this thesis, we investigate in details the magnetic shielding processes in high temperature superconductors. We aim at predicting and measuring the influence of the parameters governing the ... [more ▼]In this thesis, we investigate in details the magnetic shielding processes in high temperature superconductors. We aim at predicting and measuring the influence of the parameters governing the superconducting behaviour (e.g., the critical current density Jc and its field dependence) on the magnetic flux penetration inside hollow cylinders. Three objectives are pursued. The first objective is to characterize the performances of cylindrical magnetic shields made of various high temperature superconductors (Bi-2223, Bi-2212, Y-123) for several external parameters that can be directly controlled in the experiments. These include the temperature, the geometry of the magnetic screen, the amplitude of the applied magnetic field, its orientation (H // or ⊥ cylinder axis) and its frequency (in the case of an AC excitation). The focus has been put on the effect of the sweep rate of the applied magnetic field, dBapp/dt, on the threshold magnetic flux density, Blim, above which the magnetic shielding is no longer efficient. We show that the curve of dBapp/dt vs. Blim can be directly related to the E(J) constitutive law and we explain how the field dependence of the critical current density affects the relationship between both curves. A wide range of electric field levels is investigated in this thesis thanks to the use of a number of experimental techniques. The experimental set-ups required for these investigations are described in a separate chapter where the performances and limitations of each set-up is put forward. The second objective of the thesis is to confront experimental data and numerical simulations using models of increasing complexity. We present two numerical models that take into account the strongly non-linear E(J) relationship characterizing the superconducting behaviour. The first numerical model is based on the Brandt algorithm. This model is able to describe magnetic shielding experiments which involve time-varying magnetic fields on (i) infinite samples subjected to transverse magnetic fields or on (ii) samples of finite size in axisymmetric geometries subjected to axial magnetic fields. The second model is based on a finite element method (using the GetDP software). This model can be used for both axisymmetric 2D modelling and full 3D modelling. In the latter case, it provides extremely useful information for understanding configurations where the applied magnetic field and the hollow cylinder do not present a particular symmetry. Both 2D and 3D models are able to provide current and field distributions in the superconductor. The confrontation between experimental and modelling results allows us to better understand how physical properties (critical temperature Tc, critical current density Jc, ...) and geometry affect the magnetic shielding performances (shielding factor SF, threshold induction Blim). Conversely, we present three different practical procedures using either the analytical Bean model or a 2D numerical model in order to determine the constitutive law parameters of the superconducting materials from data measured on hollow cylinders. As a third objective, we aim at investigating how the different types of HTS magnetic screens of moderate dimensions (a few cubic centimetres) could be scaled up in order to provide larger shielded volumes. Three methods are explored. The first method to build larger magnetic screens (typically ten(s) of centimetres) is to find means to assemble several (pieces of) superconducting hollow cylinders to obtain a large shielding enclosure. Experiments are carried out on superconducting cylinders cut either along or perpendicular to their axis. The influence of the cut width and the angle of the applied magnetic field with respect to the cut plane are studied. Modellings are carried out on shorter cylinders in order to understand how the presence of the cut modifies the current distribution and thus the magnetic shielding properties. The second method consist in characterizing the magnetic shielding of several hollow cylinders made with the same superconducting material but having different sizes. This helps us in determining whether the manufacturing process is able to provide large cylinders with good magnetic shielding performances. In a last method, we investigate an architecture of superconducting magnetic screens that differs from those based on bulk hollow cylinders. The idea is to exploit the high Jc-performances of superconducting tapes (based on thin film technology) to build magnetic shielding structures which can be easily scalable. The measurement results obtained on such structures are promising as the actual limitation seems to be geometrical. Using more superconducting tapes in order to achieve a higher aspect ratio should give magnetic shields which are as efficient as bulk cylinders. [less ▲]Detailed reference viewed: 47 (12 ULg) Le contexte urbain et climatique des risques hydrologiques de la ville de Butembo (Nord Kivu/RDC)Muhindo, Sahani Doctoral thesis (2011)Butembo, a small town in the humid tropical region, is a typical case of, a city with an exceptionally rapid population growth. The spontaneous concentration of populations due to uncontrolled migration ... [more ▼]Butembo, a small town in the humid tropical region, is a typical case of, a city with an exceptionally rapid population growth. The spontaneous concentration of populations due to uncontrolled migration on a relatively small territory has led to urban sprawl. Soil sealing of large areas caused by a rapid spatial expansion of the town has generated environmental problems that affect the urban structure. The city is facing diverse hydrological risks. Progressive and regressive gully development accelerates and increasingly affects water availability. In recent years, the urban area faces floods, perceived locally as exceptional. The remobilization of old landslides locally causes damage. Since its inception, Butembo has never had an objective reference map. The only ones which are available are manually drawn. It is known that land use planning can fight effectively against most major risks in so far as the elements that govern their occurrence are known and that the areas at risk can be located and defined on the basis of objective and scientific criteria. The main goal of this thesis is to produce a map of and for the city of Butembo which can help to support decision making or at least to understand the reasons of the environmental degradation in the urban area. In that direction, this thesis leads to editing a map of hydrological risks. It is based on approaches combining remote sensing and terrain activities. A detailed analysis of rainfall events is made to see if the rains did influence the environmental problems in the town of Butembo. The results reveal an exceptional urban expansion. The urban sprawl of Butembo increased from 2,39 km² in 1957 to 85,83 km² in 2008, approximately 54 % of 158,95 km². This increase in urban area is the result of exceptional population growth in the town. Indeed, the population rose from 9 653 in 1957 to 581 449 inhabitants in 2008. This urbanization has resulted in a new land use with all the consequences on the urban landscape. Since 1957 valley and hillslope gullying remained all the time confined spatially within the diachronic urbanized expansions. Urbanization precedes the development of gullies and these are confined to areas where the runoff coefficient increased by urbanization. For the time being, there is not yet fusion between progressive and regressive gullies. In the future, flooding threats all the flat valley bottoms in the case nothing is done. Landslides are active and are in the creep phase. 11 of the 16 landslides inventoried are partially co-triggered by seismic. Finally, the damage to the urban structure cannot be ascribed to changes in the rainfall pattern over the 30 last years. All the rains of recent years are normal for the city as their recurrence time is under 6 years. The main cause of environmental problems within the city is urbanization. Remediation methods require intervention not only in the field of runoff evacuation. The problems must also be tackled upstream, on the slopes, using all the techniques that can prevent or reduce the generation of runoff. [less ▲]Detailed reference viewed: 95 (12 ULg) Identification et caractérisation de bactériocines produites par deux bactéries lactiques (Enterococcus faecium CWBI-B1430 et Enterococcus mundtii CWBI-B1431) isolées à partir de fromages frais artisanaux péruviensAguilar Galvez, Ana Consuelo Doctoral thesis (2011)A screening of lactic acid bacteria (LAB) with bacteriocin-like inhibitory activity against Listeria monocytogenes was performed. The screening was conducted in 27 traditional artisanal-produced cheeses ... [more ▼]A screening of lactic acid bacteria (LAB) with bacteriocin-like inhibitory activity against Listeria monocytogenes was performed. The screening was conducted in 27 traditional artisanal-produced cheeses obtained from different Peruvian regions. Two thousand two hundred and seventy seven strains (2277) were isolated, of which 20 exhibited bacteriocin-like inhibitory activity, two strains stand out for having higher activity against listeria, as well as stability at pH value of 2-11 and a thermal stability. The two strains were identified using 16 S ribosomal DNA method, and were registered in the GenBank database of NCBI (National Center for Biotechnology Information). These were Enterococcus faecium CWBI-B1430 (accession number EF591817) and Enterococcus mundtii CWBI-B1431 (accession number EF591816). Two of the major factors concerned in a potential health risk associated with the genus Enterococcus were evaluated, and it was demonstrated that they were sensitive to vancomycin and showed no hemolytic activity. Genetic studies showed the presence of four putative bacteriocin genes in both strains, these were enterocin A, enterocin B, enterocin P, and mundticin KS. The reverse transcription-PCR analysis was realized, the expression of the bacteriocin genes enterocin A, enterocin B, and mundticin KS in CWBI-B1430 was showed, while bacteriocin genes enterocin P and mundticin KS was demonstrated in CWBI-B1431. These results are the first report of the expression of mundticin KS in E. faecium and enterocin P in E. mundtii. Also, the expression was studied at different temperatures, unlike the enterocin P, where only a positive signal was obtained at 12 and 37°C. All other enterocin showed positive signal at 12, 30, 37 and 42°C. The production of bacteriocins on a small scale, in both strains was studied. It was investigate the influence of initial pH (4.5, 5.0, 5.5, 6.0, 6.5 and 7.0), temperature (25, 30 and 37°C) and oxygen level (anaerobic, microaerobic and aerobic). The conditions for maximizing the production of bacteriocins are : initial pH of 7.0, at 37 °C, and microaerobic conditions for CWBI-B1430 strain; initial pH of 6.5, at 37 °C, and an aerobic condition for CWBI-B1431. The influence of the source of carbon and nitrogen, as well as their concentration in the bacteriocin production, was studied. The study of the production of short-chain fatty acids by these strains of multiproducing bacteriocins, showed the propionic acid as the most important. The purification study confirmed that the two bacteria in question are multi-producing of bacteriocins, as shown by the obtained chromatograms, showing different molecular weights, different charge and hydrophobicity level. The results of in situ application of the two selected strains or their supernatant does not show the same efficiency as those obtained in vitro. Factors such as temperature and food composition may be the origin of these results. Therefore, we propose the use of both strains in the food industry, for being multi-producing bacteriocins, have broad spectrum of inhibition and because the substances that produce have functional properties that are useful in the food industry. [less ▲]Detailed reference viewed: 198 (15 ULg) THE ROLE OF CUSTOMER PERCEIVED EMPLOYEE EMOTIONAL COMPETENCE IN SERVICE ENCOUNTERSDelcourt, Cécile Doctoral thesis (2011)The present dissertation is based on three studies, sharing one common theme: employee emotional competence (EEC). The overall aim of this dissertation is to examine the effect of customer perceptions of ... [more ▼]The present dissertation is based on three studies, sharing one common theme: employee emotional competence (EEC). The overall aim of this dissertation is to examine the effect of customer perceptions of employee emotional competence on their evaluations of critical service encounters. To achieve this goal, each study builds a theoretical framework and presents empirical assessments of aspects of the issue under consideration. While psychology scholars have conceptualized, measured, and evaluated the impact of EEC in work-related relationships (i.e., internal perspective of EEC), the role of EEC in customer-related relationships (i.e., service encounters) has received little attention by marketing scholars. We argue in this dissertation that a customer perspective of EEC is necessary to examine EEC in such context. Recent studies in the service literature have suggested that EEC could be valuable in service encounters–especially in critical service encounters since customers want employees to recognize the uniqueness of their personal experience (Price et al., 1995b). Given the potential influential role of EEC in a marketing context, researchers have called for further investigation (Kidwell et al., 2011; Verbeke et al., 2008). Therefore, this dissertation approaches the concept of EEC by first focusing on emotional competence (i.e., the actual demonstration of emotionally competent behaviors by the employee) instead of emotional intelligence (i.e., the potential one employee has to demonstrate emotionally competent behaviors). In this respect, we examine customer perceptions–rather than employee perceptions or supervisor perceptions of EEC–since these last measures are subject to important biases and since only customers can evaluate if the employee has actually displayed emotionally competent behaviors during the service encounter. More specifically, the focus is on the exploration of EEC and its effects on customer outcomes. Based on a review of the literature from various disciplines and research streams, comprehensive models are constructed, summarizing theoretical propositions and hypotheses. The first study examines in a field study the impact of customer perceptions of EEC on customer satisfaction and loyalty in high-contact services. The mediating role of rapport is examined. We found that EEC influence both customer satisfaction and loyalty. Rapport mediates both relationships. The second study aims to conceptualize EEC in service encounters and to develop a short, valid, and reliable measure based on that conceptualization. By using a rigorous scale development procedure, we define EEC as customer perceptions of employees’ abilities to perceive, understand, and regulate customer emotions in a service encounter to ensure harmonious encounters. This measure of EEC is strongly related to key customer outcomes such as customer satisfaction. The third study aims to understand in an experimental design the role of EEC compared to employee technical competence (ETC) in emotionally charged service encounters. We found that EEC moderates the relationship between ETC and customer outcomes such as negative customer emotions, rapport, and service encounter satisfaction. When EEC is low, the impact of ETC on those variables is low or even non significant. When EEC is high, ETC strongly influences those customer outcomes. Together, the three studies provide rich insights on the impact of EEC on customer outcomes in a service encounter context. To improve the customer’s experience in service encounters, managers should encourage their contact employees to display emotionally competent behaviors by perceiving, understanding, and regulating customer emotions. When employees have high EEC, the impact of ETC on customers is the highest. Rapport mediates the relationship between EEC and key customer outcomes such as customer satisfaction and loyalty. [less ▲]Detailed reference viewed: 103 (9 ULg) Power Line Conductors, a Contribution to the Analysis of their Dynamic BehaviourGuérard, Suzanne Doctoral thesis (2011)Detailed reference viewed: 43 (7 ULg) Entre Union européenne et Région wallonne : multiplicité des échelons de pouvoir et subsidiarité territoriale Analyse de la subsidiarité territoriale au travers des directives Seveso, IPPC, responsabilité environnementale et de leurs mesures de transposition en Région wallonne.Hanson, Sophie Doctoral thesis (2011)La Région wallonne s’inscrit dans un contexte organisationnel particulier. D’une part, elle constitue une composante d’un État membre de l’Union européenne. D’autre part, elle fait partie d’un État à ... [more ▼]La Région wallonne s’inscrit dans un contexte organisationnel particulier. D’une part, elle constitue une composante d’un État membre de l’Union européenne. D’autre part, elle fait partie d’un État à structure fédérale comportant une entité fédérale, des entités fédérées et des collectivités locales (provinces, communes). Il est permis de s'interroger, dans ce contexte, sur la nature des relations que peut entretenir la Région wallonne avec les entités gravitant autour d’elle. Le principe de subsidiarité, dans sa fonction territoriale, peut constituer une clé de lecture dans la mesure où il est indissociable des systèmes institutionnels multi-niveaux. Il implique que ce soit l’échelon qui est le plus proche des citoyens qui soit privilégié afin de remplir une tâche. Si toutefois, il ne parvient pas à rencontrer un objectif déterminé, l’échelon supérieur peut intervenir s’il peut satisfaire ce dernier de manière plus efficace. La question centrale qui a guidé la recherche a donc été de savoir, au travers de l’exemple de la Région wallonne, si les rapports entre les échelons de pouvoir, de la commune à l’Union européenne s’effectuent en application du principe de subsidiarité, dans sa fonction territoriale. Trois directives européennes importantes ressortissant au domaine de l'environnement (Seveso, IPPC et responsabilité environnementale) ainsi que leurs mesures de transposition en Région wallonne ont été examinées à l'aune de ce principe. [less ▲]Detailed reference viewed: 55 (13 ULg) Des projets aux réseaux: la construction d'un compromisVandenborne, Emilie Doctoral thesis (2011)Cette thèse étudie la construction en réseaux des projets. Elle a pour objet une sociologie de l’action en réseaux appuyée d’une sociologie des normes et d’une sociologie de l’acteur-réseau. Elle ... [more ▼]Cette thèse étudie la construction en réseaux des projets. Elle a pour objet une sociologie de l’action en réseaux appuyée d’une sociologie des normes et d’une sociologie de l’acteur-réseau. Elle interroge les comportements collectifs autour de projets au sein du secteur biotechnologique. La question centrale qui se pose est celle de l’apparition de nouvelles formes de gouvernance réticulaire à partir d’une configuration par projets. [less ▲]Detailed reference viewed: 85 (29 ULg) Avant Hergé. Etude des premières apparitions de bande dessinée en Belgique francophone (1830-1914).Paques, Frédéric Doctoral thesis (2011)Detailed reference viewed: 77 (11 ULg) Conception et synthèse de nouveaux complexes de ruthénium pour la formation catalytique de liaisons C–CBorguet, Yannick Doctoral thesis (2011)During the last decade, catalytic methods enabling the formation of single and multiple C–C bonds have sparked a major interest from the Chemists community. Among them, olefin metathesis has emerged as a ... [more ▼]During the last decade, catalytic methods enabling the formation of single and multiple C–C bonds have sparked a major interest from the Chemists community. Among them, olefin metathesis has emerged as a powerful tool, opening unique routes to synthesize organic compounds and polymers. This is mainly due to the advent of well-defined ruthenium–benzylidene complexes first developed by Grubbs and co-workers in the early 1990’s. Since then, countless structural alterations have been made to these archetypal compounds in order to tailor their activity, stability, solubility, . . . However, the synthesis of these derivatives may be tedious and costly since it almost systematically requires the use of the Grubbs 1st generation catalyst as a starting material. Therefore, non-proprietary catalysts with high activity are still eagerly sought. This thesis is mainly focused on the design of straightforward and reliable syntheses of new complexes derived from the homobimetallic molecular scaffold (I) first reported by Severin in 2005. Our first aim was to enhance the catalytic activity of such compounds in olefin metathesis and in controlled radical reactions. [less ▲]Detailed reference viewed: 70 (12 ULg) Le Dictionnaire au second degré. Socio-logiques d'un détournement générique.Saint-Amand, Denis Doctoral thesis (2011)Detailed reference viewed: 41 (11 ULg) Rôle des moustiques Culicidae, de leurs communautés microbiennes et des réservoirs vertébrés, dans la transmission des arbovirus à MadagascarRaharimalala, Fara Nantenaina Doctoral thesis (2011)These last ten years, Indian Ocean islands have been the theatre of severe epidemics of arboviroses. However, little information was available about the local dynamics of the virus transmission and ... [more ▼]These last ten years, Indian Ocean islands have been the theatre of severe epidemics of arboviroses. However, little information was available about the local dynamics of the virus transmission and identity of the vector species and vertebrates réservoirs involved. Madagascar island was chosen for its high endemic biodiversity, contrasting climatic conditions and drastic changes in habitats due to an increase anthropic pressure. These factors increase the epidemiological risks of infectious diseases. In this context, our objective was to characterize the role of Culicidae as major vectors, the associated microbial communities, and wild vertebrates (lémurs) as potential réservoirs in the transmission arboviroses. Molecular techniques allowed udpdating the biogeography of Aedes and showed the dominance of Aedes albopictus competent to chikungunya virus. Other mosquitoes captured belonged to Culex antennatus, Culex decens, Culex quinquefasciatus et Mansonia uniformis. The bacterium Wolbachia was detected in most mosquito especies,but Culex antennatus. Searching of arboviruses by qRT‐PCR revealed infection of Culex antennatus and lemurs (Lepilemur edwardsi et Eulemur rufus) by the rift valley fever virus. [less ▲]Detailed reference viewed: 20 (1 ULg) Contribution to the epidemiology of bovine tuberculosis in northern EcuadorProaño Perez, Freddy Doctoral thesis (2011)See attached document, page viiDetailed reference viewed: 14 (3 ULg) Impact des facteurs de contexte sur le design des systèmes de contrôle de gestion dans les collectivités locales béninoises: Une approche contingenteTogodo Azon, Degodo Aimé Doctoral thesis (2011)Très peu d’études empiriques ont analysé les facteurs qui influencent le design des systèmes de contrôle de gestion dans les collectivités locales de l’Afrique au Sud du Sahara. La présente recherche, qui ... [more ▼]Très peu d’études empiriques ont analysé les facteurs qui influencent le design des systèmes de contrôle de gestion dans les collectivités locales de l’Afrique au Sud du Sahara. La présente recherche, qui prend pour cadre le Bénin, explore les facteurs qui influencent le design des systèmes de contrôle de gestion dans les communes béninoises. Pour ce faire, nous avons développé six chapitres complémentaires articulés en trois parties. Dans une première partie, nous avons fait un état de la littérature qui aboutit à un modèle conceptuel. Ce modèle présente les différents outils de contrôle de gestion et les facteurs organisationnels et extra-organisationnels susceptibles d’influencer le choix des outils. La deuxième partie est une étude empirique hypothético-déductive à base de questionnaires sur soixante-dix communes béninoises. Dans cette partie, nous avons présenté les caractéristiques des systèmes de contrôle de gestion utilisés dans les communes béninoises et identifié les facteurs institutionnels et socioculturels qui influencent la configuration organisationnelle et le design des systèmes de contrôle de gestion dans les collectivités locales béninoises. La troisième partie est une étude empirique inductive qui présente trois études de cas. Ces études de cas, utilisées en complément et en approfondissement de l’analyse quantitative, ont révélé le rôle capital que joue le style de management adopté par les autorités locales dans la gestion du changement organisationnel et dans la maitrise des pressions politiques locales. Enfin, la recherche s’achève en dégageant les principales implications de notre modélisation sur l’introduction de la Nouvelle Gestion Publique en Afrique sub-saharienne et sur le type de décentralisation choisi par le Bénin. [less ▲]Detailed reference viewed: 88 (11 ULg) Génétique de la neuropathie laryngée récurrente chez le chevalDupuis, Marie-Capucine Doctoral thesis (2011)Recurrent laryngeal neuropathy (RLN), known as « roaring » or « whistling », has been considered as the most important equine airway disease of the horse. It can cause abnormal respiratory noise during ... [more ▼]Recurrent laryngeal neuropathy (RLN), known as « roaring » or « whistling », has been considered as the most important equine airway disease of the horse. It can cause abnormal respiratory noise during fast exercise, secondary to a reduced abduction of the left arytenoid cartilage, which may impair performance. Despite significant research into the disease, some aspects, such as etiology and pathogenesis, remain unknown. Several papers suggest a genetic basis but molecular studies have never been reported. Using the EquineSNP50 Beadchip, we genotyped 234 cases (196 Warmbloods, 20 Trotters, 14 Thoroughbreds and 4 Draft Horses), 228 breed-matched controls and 69 parents. Linkage disequilibrium and population structure were quantified before performing single marker and haplotype-based association studies, as well as family-based linkage analyses. Two genome-wide suggestive loci were identified on chromosomes 21 and 31, driven by the enrichment of a “protective” haplotype in controls compared to cases. Our study indicates that predisposition to RLN has a complex determinism, probably involving a high number of genes, of which the candidates on chromosome 21 and 31 may have the largest effects. We performed a copy-number variants analysis on the same data. After characterization of the regions harbouring these variants, an association study with RLN was conducted. A duplication on chromosome 10 was identified in ten affected horses and two unphenotyped parents that were sharing a long haplotype. This work provides novel insights in the genetic determinism of NLR and opens new field of research. If the genuine nature of these loci is confirmed in independent cohorts, identifying the causative genes may increase our understanding of RLN pathogenesis. Assuming that RLN is very polygenic, predictive diagnosis and selection may be more effective using a genomic selection type of approach. [less ▲]Detailed reference viewed: 32 (13 ULg) Etudes sur le syntagme nominal en néo-égyptien: l'article zéro, la possession attributive et le changement de genreNéven, Laurence Doctoral thesis (2011)Le syntagme nominal offre de nombreuses possibilités de recherches. Les études peuvent se concentrer sur des syntagmes nominaux simples ou complexes et s’intéresser aux différents éléments qui les ... [more ▼]Le syntagme nominal offre de nombreuses possibilités de recherches. Les études peuvent se concentrer sur des syntagmes nominaux simples ou complexes et s’intéresser aux différents éléments qui les composent. De même, les relations syntaxiques entre deux ou plusieurs syntagmes nominaux peuvent faire l’objet d’une attention particulière et les recherches peuvent se focaliser sur une langue ou un état de langue spécifique, ou, au contraire, s’envisager dans une perspective typologique prenant en compte un nombre plus ou moins élevé de langues. Dans le cadre de ma thèse de doctorat, j’ai décidé de me concentrer sur le néo-égyptien et d’étudier trois points essentiels qui sont la détermination, la possession et le genre. Le premier chapitre de ce travail s’est intéressé à la détermination des substantifs et plus particulièrement aux articles. L’originalité de cette partie réside dans le fait de proposer et de montrer l’existence d’un article zéro qui peut être intégré au paradigme des articles. Celui-ci se distingue dès lors d’une absence d’article. L’opposition entre ces deux concepts repose sur certains critères fondamentaux. Il faut ainsi que le syntagme nominal précédé de zéro puisse commuter avec un syntagme nominal précédé d’un article défini et/ou indéfini. Il doit également se trouver dans un environnement syntaxique similaire et offrir à l’ensemble une signification particulière. J’ai constaté qu’il existait des alternances entre l’article défini, indéfini et zéro (apposition, générique et vocatif). Si ce n’est dans le cas du générique, l’usage d’un zéro n’est pas significatif. J’ai également étudié l’emploi des déterminants au sein de certaines constructions spécifiques et de catégories de noms (abstraits, collectifs, comptables, de fonction, massifs et propres). Seuls les noms abstraits, comptables et massifs font usage d’un zéro significatif. L’article défini sert à spécifier l’entité ou à référer à une entité connue à la fois du locuteur et de l’interlocuteur. L’article indéfini réfère également à une entité particulière, mais spécifique ou non. Enfin, l’article zéro est utilisé lorsque l’on veut référer à une entité homogène et dénote une non-quantification absolue. L’opposition à deux membres, c’est-à-dire entre l’article défini et zéro s’est révélée pertinente dans le cas des noms abstraits et des noms comptables ; et l’opposition à trois membres, c’est-à-dire entre l’article défini, l’article indéfini et zéro s’est révélée pertinente avec les noms massifs. Il semble donc que la présence d’un article zéro soit principalement liée à certaines catégories de substantifs et ne réponde pas à des critères syntaxiques selon sa présence dans telle ou telle construction. L’objectif de mon chapitre II était d’offrir une classification des divers procédés permettant d’exprimer la possession attributive en néo-égyptien. L’examen de ces moyens formels s’est réalisé en se fondant sur trois points principaux : l’environnement syntaxique et sémantique, l’influence du genre littéraire et/ou du registre de texte et l’évolution diachronique. L’opposition entre l’article possessif et le pronom suffixe est principalement une opposition de registre textuel, mais elle peut également être d’ordre syntaxique ou sémantique. L’opposition entre l’article possessif et le pronom indépendant concerne la définition des possédés. Le pronom indépendant est employé lorsque le substantif est indéfini ou précédé du démonstratif. La préposition m-di prendra le relais du pronom indépendant dans l’expression de la possession attributive, mais les prémices de ce remplacement fonctionnel ne sont pas perceptibles avant la fin de la 20e dynastie. En revanche, l’opposition entre le génitif direct et le génitif indirect est quasi inexistante. En effet, le génitif direct n’est guère plus productif et se limite pour la majeure partie aux titres de fonctions. L’objectif de mon dernier chapitre était de montrer qu’ont existé en égyptien ancien des changements ou des variations de genre. Cette étude ne pouvait se prétendre exhaustive en regard du corpus délimité. J’ai donc voulu poser les premiers jalons et proposer des hypothèses qui expliqueraient certains de ces changements ou de ces flottements. En me fondant principalement sur la contribution de Michel Roché, concernant les variations du genre en langue française, j’ai établi cinq schémas prenant en compte les différentes possibilités. Les principaux arguments qui m’ont été utiles pour l’analyse du genre sont les articles ou leurs substituts et l’accord du pseudo-participe et du pronom de rappel (pronom suffixe). Cela m’a permis de mettre en exergue plusieurs mots qui ont connu un flottement dans l’attribution du genre avec un retour au genre originel (principalement des parties du corps), ainsi que des substantifs qui ont changé de genre entre le néo-égyptien et le démotique (AH.t et btA). Le mot dmi « ville », quant à lui, correspond peut-être à un dédoublement de genre dans lequel le nouveau lexème dmi.t se spécifie sémantiquement. Enfin, l’emprunt de mots sémitiques a également provoqué des confusions dans le genre des noms et plus spécifiquement parmi les substantifs qui originellement se terminent par un –t appartenant au radical. J’ai proposé plusieurs hypothèses pour expliquer ces changements ou flottements de genre. Il s’agit de l’absence ou la rareté du déterminant, des changements phonétiques, de la proximité formelle et sémantique de deux substantifs et de l’emprunt à des langues étrangères. [less ▲]Detailed reference viewed: 36 (11 ULg) Contribution to the study of waste heat recovery systems on commercial truck diesel engines.Espinosa, Nicolas Doctoral thesis (2011)Detailed reference viewed: 88 (17 ULg) SEISMICALLY RETROFITTING AND UPGRADING RC-MRF BY USING EXPANDED METAL PANELSPhung Ngoc, Dung Doctoral thesis (2011)Reinforced concrete moment resisting frames (RC-MRFs) have been widely used as the main structural resisting systems for over 30 years based on their capacity in resisting both gravity loads and lateral ... [more ▼]Reinforced concrete moment resisting frames (RC-MRFs) have been widely used as the main structural resisting systems for over 30 years based on their capacity in resisting both gravity loads and lateral forces like winds or earthquakes and on low cost of construction. However, there have been still many existing RC-MRFs not designed according to any modern seismic code. This may lead to some undesired failures under a rather low intensity earthquake. There are several existing retrofitting systems available for seismically retrofitting RC-MRFs, such as steel braces, steel plate or RC shear walls, base isolators…In those, some are able to increase the stiffness, strength, deformation and energy absorbing capacity of the structures and some are able to reduce the influence of the seismic actions on the structure. Despite having advantage in increasing the stiffness and strength for the buildings, the use of bulky systems like RC shear walls to retrofit buildings under seismic actions becomes more limited due to its complication in erection and high costs for foundation. The use of lighter retrofitting systems such as steel braces or shear walls made from steel or aluminium… has been becoming more favourable. Made from sheet steel or various alloys by cutting and simultaneous stretching cold, expanded metal is considered as a macro-foam material. An expanded metal panel (EMP) with rectangular dimensions of 1.25m x 2.5m having many rhomb shape stitches with different geometrical sizes is the popular product. Currently it is employed primarily in the areas of protection (fencing, gates) and architecture. The final goal of this study is to consider a new application different in the field of civil engineering and more specifically that of the earthquake resistance of buildings. The work plan includes two main parts. This first part will set the EMP over existing techniques and see if its use is justified in the context of earthquake resistance. In addition, a more detailed description of the EMP is considered. In this way, the different data required for modelling the new resistance system are known and analyzes, tests and comparisons can be made in order to validate the use of EMP in the context of earthquake resistance. A complete study on pure shear behaviour of EMP under monotonic and quasi-static cyclic loading has been developed including experimental, theoretical and numerical investigations. To apply EMP in seismically retrofitting RC-MRFs, thirty two RC-MRFs have been designed according to two codes EC2 and EC8. The seismic performance of the studied frames has been evaluated using Pushover and NLTH analyses. For the frames designed according to EC2 or EC8 with low ductility, some prominent deficiencies are found, such as incomplete load path or the soft-story failure. Based on the knowledge of deficiencies of the existing frames, many attempts to exploit EMP to seismically retrofit the existing frames have been made. All frames designed according to EC2 and EC8 with Low Ductility Class need to retrofit because they cannot reach the target displacements due to premature failure of beam-column joints. To seismically retrofit them by using EMP, a design procedure based on Direct Displacement Based Design (DDBD) has been proposed. The design is an iterative procedure, starting with the selection of the target displacements at the top based on the results from Pushover analysis. They are usually less than the limit displacements at which RC frames collapse due to crushing of the concrete at beam-column joints. These displacements are also the target ones for the retrofitted frames. The results from design procedure proposed are significantly affected by some typical factors such as selected target displacements and capacity of the existing frames contributing to overall resistance of the retrofitted frames, equivalent viscous damping of the EMP and MRFs as well as geometrical dimensions of the existing frames. The retrofitted design results, assessed by Pushover and NLTH analyses, have indicated that DDDB is a useful tool to design EMP to seismically retrofit the existing frames. With EMP, all retrofitted frames can reach target displacements under design earthquakes without any brittle failure, not like the original frames. However, EMP cannot improve the behaviour of the beam-column joints. Under the earthquakes greater than design ones, failure of the nodes is still observed in all retrofitted frames. The comparison of the seismic performance of the frames before and after being retrofitted has shown that EMP is able to reduce the influence of the earthquake on the original frames by increasing their strength and stiffness and by absorbing the seismic energy. Proposed design procedure of connection between EMP and the frame elements is applicable. This was verified in the experiments when connecting EMP with the steel testing frames. The design approach for the connection is based on Capacity Design, all starting with the maximum resistance of the bars in a rhomb-shape stitch of the EMP and the tension field action developed in the EMP during shear loading. However, it is necessary to perform tests on the connections between EMP and the RC beams and columns. Also, improved practical details can be developed. [less ▲]Detailed reference viewed: 84 (9 ULg) Contribution to Entanglement Theory, Applications in Atomic Systems and Cavity QEDGillet, Jérémie Doctoral thesis (2011)We introduce in this thesis two entanglement detection criteria, the Schrödinger-Robertson partial transpose inequality, which can be implemented experimentally in a variety of systems and generalized N ... [more ▼]We introduce in this thesis two entanglement detection criteria, the Schrödinger-Robertson partial transpose inequality, which can be implemented experimentally in a variety of systems and generalized N-qubit concurrences, which can be used to evaluate multipartite entanglement in N-qubit mixed states. Then, we investigate ways to experimentally produce entanglement by giving a theoretical model which successfully describes the dipole blockade effect. We study its possible applications in systems of two and three two-level atoms as well as its relations with the EITeffect in systems of two three-level atoms. Finally, we show the possibility of two-photon processes in a system of two two-level atoms embedded in a cavity by using perturbation theory and a full master equation approach. We unveil interesting features of blockade and transparency in such cavity QED systems. [less ▲]Detailed reference viewed: 46 (12 ULg) Etude des protéines régulées par le froid chez une bactérie antarctique : approche protéomique et biochimique de la psychrophiliePiette, Florence Doctoral thesis (2011)Detailed reference viewed: 27 (11 ULg) Implication des cellules Natural Killer (NK) dans le développement des lésions associées à l'infection par les papillomavirus humains (HPV)Renoux, Virginie Doctoral thesis (2011)Persistent infections with high-risk papillomavirus (HPV) are associated with more than 25% of cancers induced by infectious agents. Nevertheless, the two vaccines preventing HPV infection have no ... [more ▼]Persistent infections with high-risk papillomavirus (HPV) are associated with more than 25% of cancers induced by infectious agents. Nevertheless, the two vaccines preventing HPV infection have no therapeutic efficacy and it has been estimated that there will be no measurable decline of HPV-associated tumours before 2040. The immune system is able to control, at least partially, HPV infection and subsequent tumour development. Around 90% of HPV-infected women will clear the virus within two years, but the immune effectors responsible for this viral clearance are unknown. Hence, the aim of this study was to determine if Natural Killer (NK) cells could play a role in the immune response against HPV infection and related cancers. The first part of this work was focused on the in vitro interaction of NK cells with L1 and L1L2 Virus Like Particles (VLP) of HPV16. We observed that, in the presence of HPV-VLP, NK cells displayed a higher cytotoxic activity against HPV+ cells by increasing the exocytosis of their cytotoxic granules and by secreting TNF-α and IFN-γ. NK cell activation was correlated with a fast entry of HPV-VLP by macropinocytosis and we determined that cell surface CD16 expression was necessary for HPV internalization, but also for degranulation and cytokine production. In the second part, to understand the molecular mechanisms of HPV-VLP stimulation, we investigated the signalling pathways operating in NK cells to trigger their cytotoxic activity in the presence of viral particles. We observed that the MAP kinases ERK and p38 were phosphorylated in the presence of both L1 and L1L2 HPV-VLP. Using specific inhibitors, we demonstrated that phosphorylation of these MAPK was required for degranulation and cytokine secretion by NK cells in the presence of VLP. In conclusion, NK cell activity could be an important player in the immune response contributing to viral clearance and to regression of HPV-induced cervical lesions. [less ▲]Detailed reference viewed: 59 (15 ULg) Modélisation spatialement distribuée et physiquement basée d’écoulements hydrologiques et hydrodynamiques pour l’aide à la gestion d’ouvrages hydrauliquesKhuat Duy, Bruno Doctoral thesis (2011)La gestion des ressources en eau constitue une préoccupation qui prend une place de plus en plus importante dans nos sociétés. Les événements climatiques extrêmes subis ces dernières années (pluies ... [more ▼]La gestion des ressources en eau constitue une préoccupation qui prend une place de plus en plus importante dans nos sociétés. Les événements climatiques extrêmes subis ces dernières années (pluies diluviennes mais également sécheresses) montrent toute la nécessité d’une meilleure compréhension des phénomènes en cause afin de mettre en place une gestion efficace des ressources. Ces études passent notamment par le développement de logiciels de simulation basés sur des modèles hydrologiques et hydrodynamiques fiables capables de représenter correctement les phénomènes réels mis en jeu. Cette thèse contribue à la mise en place d’un outil de modélisation spatialement distribuée et physiquement basée d’écoulements hydrologiques et hydrodynamiques, destiné notamment à fournir une aide précieuse pour la gestion d’ouvrages hydrauliques. Chaque composante de modélisation du circuit hydrologique, depuis la pluie jusqu’à l’exutoire de la rivière, est examinée. Des améliorations ou développements plus fondamentaux sont alors proposés pour améliorer la qualité de modélisation. Entre autres, cette thèse aborde en profondeur des sujets tels que la prise en compte de la microtopographie dans la représentation des phénomènes de surface (stockage dans les dépressions, écoulement en ruisselets, relations hauteurs-section-volume…), le calcul de l’infiltration (modèle à fronts multiples, effet de l’occupation du sol…) ou l’écoulement dans la couche hypodermique (écoulement saturé/non saturé, mise en pression…). Les recherches et développements portent également sur l’écoulement dans les axes de concentration (création d’un réseau de rivières cohérent à la fois avec le modèle numérique de terrain et les levés précis sur site, exploitation adéquate des données de section, modélisation efficace des ouvrages en charge ou non…). La modélisation des surfaces imperméables (avec séparation des zones égouttées ou non) est également abordée de façon détaillée, dans le cadre d’une application sur un bassin versant instrumenté de 130 km². Cette application envisage aussi bien la modélisation d’un événement ponctuel que des simulations à long terme. Enfin, l’étude d’un bassin peu instrumenté permet de montrer la large applicabilité et sa capacité à servir de support efficace dans la gestion des rivières et des ouvrages hydrauliques associés. [less ▲]Detailed reference viewed: 30 (5 ULg) Mathematical modeling of biogeochemical processes associated to a coccolithophorid (Emiliania huxleyi) bloom - Study of the seasonal and long-term variability of biogeochemical properties in the Black Sea using a Data Interpolating Variational Analysis (DIVA)Joassin, Pascal Doctoral thesis (2011)A OD biogeochemical model has been developed to represent coccolithophorid physiological features concerned by carbon export (primary production, active DOC excretion, TEP formation, and calcification ... [more ▼]A OD biogeochemical model has been developed to represent coccolithophorid physiological features concerned by carbon export (primary production, active DOC excretion, TEP formation, and calcification) and susceptible to be sensitive to varying pCO2. The model is initially calibrated and validated using a large set of biogeochemical data monitored during Emiliania huxleyi blooms induced in a mesocosm experiment, under present-day pCO2 conditions. Afterwards, impacts of varying pCO2 conditions on Emiliania huxleyi physiology are investigated using biogeochemical variables monitored in mesocosms under low and high pCO2 conditions. The methodology promotes a double approach: the recalibration model parameters’ that optimizes the representation of observations from low and high pCO2 treatments, and the utilization of a RM ANOVA procedure to indicate significant differences between biogeochemical variables monitored during blooms induced in low and high pCO2 treatments. Since the early 1970’s, the Black Sea ecosystem has suffered significant ecological alterations, essentially caused by anthropogenic impacts. Dam constructions on the Danube River in combination with heavy nutrients discharge via the riverine run-off lead to strong modifications of its physical and biogeochemical properties, with final consequences consisting in an enhancement of the typical anoxic state of the deep waters. The long-term evolution of key biogeochemical variables (oxygen, hydrogen sulfide, and chlorophyll) has been studied through the reconstruction of horizontal fields, using long time data series and the DIVA interpolating tool. In addition, the examination during the best sampled period (1986-1993) of these biogeochemical variables’ fields, completed with nitrates and phosphates fields, highlighted seasonal and horizontal variability within typical sections of their profiles. [less ▲]Detailed reference viewed: 34 (6 ULg) Etude comparée de l’écologie de deux espèces jumelles de Chiroptères (Mammalia : Chiroptera ) en Belgique: l’oreillard roux (Plecotus auritus) (Linn., 1758) et l’oreillard gris (Plecotus austriacus ) (Fischer, 1829).Motte, Gregory Doctoral thesis (2011)Introduction The purpose of this study is to verify one of the principal rules of ecology: the principle of exclusive competition, by using the sibling species of long-eared bats present in Belgium as a ... [more ▼]Introduction The purpose of this study is to verify one of the principal rules of ecology: the principle of exclusive competition, by using the sibling species of long-eared bats present in Belgium as a model: the brown long-eared bat (Plecotus auritus) and the grey long-eared bat (Plecotus austriacus). Two similar species present in the same region and, what is more, share the same roost, must differ according to certain aspects of their ecological niche in order to be able to co-exist (MacNab 1971). In order to determine the resource sharing mechanisms between the two species, we have compared the three important dimensions of their ecological requirements: the use of trophic resources by means of faecal analysis and the use of space and time by radio-tracking. Trophic resources One hundred and thirty samples (4688 droppings, 6388 occurrences) taken from 5 single-species colonies of P. austriacus, 5 single-species colonies of P. auritus and from a mixed colony have been taken into account in the analysis of the summer diet. With the help of a first model constructed with the aid of generalized linear regressions, we have shown that, independently of the cohabitation conditions (single-species and mixed colonies), the two species have similar dietary requirements. Qualitatively, the same types of prey are consumed : Lepidoptera, Diptera (Craneflies, Cyclorrhapha and others Diptera), Coleoptera, Arachnids and Dermaptera. Small quantitative differences of between 3% to 8%, were seen to exist : P. austriacus consumes slightly more Coleoptera and Lepidoptera and fewer Craneflies than P. auritus. With the help of a second model enabling interspecific comparison of the diet according to whether the animal belonged to the single-species colonies or the mixed colony, we were able to show that the differences were more marked. When P. austriacus belong to single-species colonies, with reference to single-species colonies of P. auritus, predicted value indicate that they consume more Coleoptera (+ 5,0 %, p = 0,001) Lepidoptera (+ 14,4 %, p < 0,0005) and fewer Arachnids (- 8,3 %, p < 0,0005), Dermaptera (- 8,8%, p < 0,0005) and Craneflies (- 9,5 %, p = 0,009). This leads us to believe that the proportion of non-flying or diurnal prey gleaned by P. auritus is 2,5 times greater than that of P. austriacus. On the other hand, when P. austriacus belongs to the mixed colony, in reference to the P. austriacus single-species colonies, it changed its feeding behaviour. The predicted consumption of Arachnids and Dermaptera is higher, 14,5 % (p < 0,0005) and 11,3 % (p < 0,0005) respectively, while the consumption of Lepidoptera is much less (- 25,6 %, p < 0,0005). The syntopic P. austriacus also consume more craneflies (+ 7,9 %, p = 0,034) but fewer Coleoptera (-11,1 %, p = 0,009). This shows that P. austriacus posesses surprising adaptation abilities. The diet of the P. auritus of the mixed colony in relation to the single-species P. auritus, only showed slight variations on the other hand : - 7% (p = 0,006) for the Cyclorrhapha and - 4% (p = 0,002) for the Dermaptera. In syntopy, the study of seasonal variations has shown that the quantitative differences were significant at the end of gestation and lactation when the energy requirement is at its highest. In June, P. austriacus consumes more Arachnids (p = 0,046), in July, more Arachnids (p = 0,020) and fewer Lepidoptera (p = 0,020). In August, they consume more Dermaptera (p = 0.019), fewer Coleoptera (p = 0.032) and Lepidoptera (p = 0.034). Winter trophic ecology Our study has also led to the discovery of a little-known aspect of the ecology of chiroptera: winter trophic ecology. The results have shown that long-eared bats consume at least 70% of their prey which they capture by gleaning (Spiders, Dermaptera, Cyclorrhapha). These results have made it possible to confirm that the two species possess the ability to glean their prey. Spatial and temporal resources Twenty-two Plecotus were used for the analysis : seven P. auritus in Gozin, six P. austriacus in Gembes, five P. auritus and four P. austriacus in Pondrome (mixed colony). Eighty-four nights of monitoring corresponding to the discovery of 111 hunting grounds were used for the analyses. The results show that the use of space by P. auritus and P. austriacus contain similarities. The distance of the hunting grounds, the number of grounds visited per night, the duration of their use, their surface and the individual area of daily activity are similar. In the same way, contrary to what the literature suggests, it seems that P. auritus possesses the ability to exploit the open or semi-open areas like the meadows surrounded by linear woodland elements, while P. austriacus possesses the ability to exploit equally well the closed areas such as woods. In syntopy, the two species showed a different selection of habitats (grasslands, leafy woods,, gardens, edges for P. auritus and leafy or coniferous woods, gardens and edges for P. austriacus), P. auritus spending 64% of hunting time above the grassland against 83% in the woods for P. austriacus. On the other hand, in comparison with the two single-species colonies, the division of hunting time around the roost is more spread out in terms of space and the number of hunting grounds visited by night is more important. No difference in the exploitation of temporal resources was detected; the later departures from the Gozin colony were attributed to the presence of artificial lighting placed in front of the roost. The mechanisms allowing resources partitioning In the case of single-species colonies we have shown the existence of trophic resources partitioning. In fact, P. austriacus showed a diet less rich in Arachnids, Dermaptera, Craneflies and richer in Coeloptera and Lepidoptera than P. auritus. However, in syntopy, P. austriacus clearly modified its diet by consuming more Arachnids and Dermaptera to the detriment of Coleoptera and Lepidoptera. The consumption in Arachnids and Dermaptera remains higher than those of single-species P. auritus. Whether for single-species colonies or mixed colonies, trophic resources partitioning is quite evident. As requirements in terms of syntopy were modified, the results lead us to assume that inter-specific competition exists between this sibling species. The differences observed in the diet are probably dictated by a different use of the habitats. Indeed, in relation with the ecology of prey, the results of habitats use have made it possible to show that habitat partitioning occurs between the two species of long-eared bat. Our results therefore constitute a good illustration of the principle of competitive exclusion. Whether in the case of single-species colonies or mixed colonies, the two species share the trophic and spatial resources which allow them to co-exist. Recommendations for the conservation of the species To satisfy the requirements of the summer diet, it is necessary to maintain a network of diverse habitats composed of gardens, meadowlands, humid zones, hedges, bushes, tree alignments, leafy or mixed woodlands, preferably hygrophilous, allowing for the development of undergrowth and clearings. The results of the selection of surface habitats have globally confirmed the importance of these habitats used as hunting grounds. The selection of linear habitats such as tree-lines, hedges, bushes and edges also show the importance of ecological networks and the potentially damaging effects of the fragmentation of habitats on the bat population. In order to integrate the spatial requirements of P. austriacus, we recommend the establishment of a minimum protection perimeter of 3500 metres around the nest. With regard to P. auritus, it would be judicious to protect a minimum perimeter of a radius of 2000 metres. [less ▲]Detailed reference viewed: 57 (9 ULg) Optimization Methods for the design and production of Naval StructuresBay, Maud Doctoral thesis (2011)In the past decades the marine industry has undergone significant evolution and the production of large passenger ships faced dramatic changes. The size, the complexity and the security standards of the ... [more ▼]In the past decades the marine industry has undergone significant evolution and the production of large passenger ships faced dramatic changes. The size, the complexity and the security standards of the ships have increased and the ship-owners have become less and less willing to wait once the order is placed. In the meantime, due to growing intense competition, the shipyards have had to improve their efficiency and master their production costs: they progressively moved from manufacture to automated production processes. As a consequence, the shipyards have now to meet this difficult challenge: produce more complex ships, cheaper and faster. In the first part of the thesis we consider the structural optimization problem that arises in the early design phase of a project. Given a vessel overall dimensions and form, structural optimization consists in defining the scantling of the structure’s constitutive elements so as to minimize its total weight or cost, while taking weight, robustness and security issues into account. Designers have to make the most adequate choices within a very short period of time. The decisions made during the design phase have a major impact on the final structure and on its production cost. We propose new algorithms to compute near-optimal solutions of the discrete structural optimization problem. In the second part of the thesis, we turn to the building process of large ships and we present new methods to improve production facility management of shipyards. The ship building process requires the production and the assembly of tens, or even hundreds of thousands of steel elements. We define a space and time allocation problem that arises in assembly halls producing large building blocks and we develop algorithms for its solution. A successful implementation of a flexible and robust application is nowadays in use at a shipyard. [less ▲]Detailed reference viewed: 39 (7 ULg) Financement de l'entrepreneuriat rural dans la Région du Centre au CamerounAhouissou, Brice Anicet Doctoral thesis (2011)L’une des principales contraintes des micros entrepreneurs ruraux est l’absence de structures de financement adaptées susceptibles de favoriser leur accès au financement à moindre coût avec des conditions ... [more ▼]L’une des principales contraintes des micros entrepreneurs ruraux est l’absence de structures de financement adaptées susceptibles de favoriser leur accès au financement à moindre coût avec des conditions moins contraignantes. Face à ce problème, il convient de se demander s’il n’est pas possible de développer des stratégies de financement adaptées aux micros entrepreneurs ruraux. C’est la réponse à cette question qui a servi de fil conducteur à ce travail. L’objectif global de la recherche est d’apporter une contribution à l’identification et à la réduction des principales contraintes auxquelles les entrepreneurs ruraux sont confrontés dans le financement de leurs activités. La méthodologie mise en œuvre s’est appuyée sur le suivi mensuel de 50 micros entrepreneurs pendant une année. Une enquête de validation a été organisée à la fin du suivi auprès de 141 micros entreprises, 19 usuriers et 21 Etablissements de microfinance (EMF). La mauvaise estimation des besoins de trésorerie, les taux d’intérêts élevés des crédits octroyés, les délais courts des remboursements, les faibles montants des emprunts sont les principales contraintes des micros entrepreneurs ruraux dans l’accès au financement mises en exergue dans cette recherche. Ces difficultés des micros entreprises sont, entre autres, dues à l’offre inadéquate des structures de financement formelles. En conclusion, il est proposé la mise en place d’un fonds de refinancement des EMF et la mise en œuvre d’un modèle de financement adapté à l’entrepreneuriat rural dans la région du Centre. [less ▲]Detailed reference viewed: 105 (25 ULg) Sustainable energy conversion through the use of Organic Rankine Cycles for waste heat recovery and solar applicationsQuoilin, Sylvain Doctoral thesis (2011)This thesis contributes to the knowledge and the characterization of small-scale Organic Rankine Cycles (ORC). It is based on experimental data, thermodynamic models and case studies. The experimental ... [more ▼]This thesis contributes to the knowledge and the characterization of small-scale Organic Rankine Cycles (ORC). It is based on experimental data, thermodynamic models and case studies. The experimental studies include: 1. A prototype of small-scale waste heat recovery ORC using an open-drive oil-free scroll expander, declined in two successive versions with major improvements. 2. A prototype of hermetic scroll expander tested on vapor test rig designed for that purpose. The achieved performance are promising, with expander overall isentropic effectivenesses higher than 70% and cycle efficiencies comparable or higher than the typical efficiencies reported in the scientific literature for the considered temperature range. New steady-state semi-empirical models of each component are developed and validated with the experimental data. The global model of the ORC prototype allows predicting its performance with a good accuracy and can be exploited to simulate possible improvements or alternative cycle configurations. Dynamic models of the cycle are also developed for the purpose of evaluating the system's reaction to transient conditions. These models are used to define and compare different control strategies. The issues of cycle optimization and fluid selection are treated using the steady-state semi-empirical models. The thermodynamic optimization of such cycles is first demonstrated by practical examples. Furthermore, three different methods for fluid selection are proposed, investigated and compared. Their respective advantages and fields of application are described. Finally, two prospective studies of small-scale ORC systems are proposed. The first one is a solar ORC designed for the rural electrification of remote regions in Africa. This prototype aims at competing with the photovoltaic technology, with the advantage of generating hot water as by-product. The second prospective study deals with the recovery of highly transient heat sources. Advanced regulation strategies are proposed to address the practical issues inherent to such systems. These strategies are compared with the state-of-the-art strategies and show a non-negligible potential of performance improvement. [less ▲]Detailed reference viewed: 2753 (75 ULg) Compétitivité des filières rizicoles burundaises: le riz de l'Imbo et le riz des maraisGahiro, Léonidas Doctoral thesis (2011)Le riz est une culture récente, pratiquée surtout dans la plaine de l'Imbo et dans les marais de moyenne altitude du Burundi. D'une part, les ressources disponibles et les technologies de production ... [more ▼]Le riz est une culture récente, pratiquée surtout dans la plaine de l'Imbo et dans les marais de moyenne altitude du Burundi. D'une part, les ressources disponibles et les technologies de production rendent le riz de l'Imbo plus compétitif que le riz des marais. D'autre part, la majorité des qualités locales s'avèrent moins compétitives que celles importées de l'Asie et la Tanzanie. [less ▲]Detailed reference viewed: 138 (26 ULg) Contribution au développement d'un dispositif expérimental d'atomes froids de fer et spectroscopie à ultra-haute résolution de cet atomeKrins, Stéphanie Doctoral thesis (2011)Le présent travail est dédié à la conception, la modélisation et l'implémentation d'un dispositif expérimental visant, pour la toute première fois, à piéger et à refroidir par laser des atomes de fer ... [more ▼]Le présent travail est dédié à la conception, la modélisation et l'implémentation d'un dispositif expérimental visant, pour la toute première fois, à piéger et à refroidir par laser des atomes de fer. Dans ce cadre, une contribution majeure au développement de ce dispositif est rapportée ici. Cette contribution comprend notamment la mise en place de dispositifs de stabilisation laser sub-MHz adaptés aux transitions spécifiques de l'atome de fer à 372 et 358 nm, ainsi que l'implémentation d'un ralentisseur Zeeman sur des faisceaux de ces atomes issus d'un four à haute température. Par ailleurs, des déterminations à ultra-haute résolution de grandeurs spectroscopiques fondamentales liées aux effets isotopiques et de structure hyperfine des transitions à 372 nm et 373.7 nm du fer sont rapportées pour la toute première fois. Une comparaison extrêmement précise de la position de la raie du fer à 358 nm par rapport à la raie de l'iode moléculaire R(90)3-10 à 13957.8542 cm-1 est également présentée. Cette comparaison met à disposition avec la précision requise la dernière donnée spectroscopique qui était inconnue dans la littérature scientifique pour une mise au point optimale du refroidissement laser d'atomes de fer. Elle ouvre la voie à l'implémentation finale du dispositif présenté dans ce travail. [less ▲]Detailed reference viewed: 28 (8 ULg) Residual Stress in Veneering CeramicMAINJOT, Amélie Doctoral thesis (2011)Detailed reference viewed: 3 (0 ULg) On the dichotomic collective behaviors of large populations of pulse-coupled firing oscillatorsMauroy, Alexandre Doctoral thesis (2011)The study of populations of pulse-coupled firing oscillators is a general and simple paradigm to investigate a wealth of natural phenomena, including the collective behaviors of neurons, the ... [more ▼]The study of populations of pulse-coupled firing oscillators is a general and simple paradigm to investigate a wealth of natural phenomena, including the collective behaviors of neurons, the synchronization of cardiac pacemaker cells, or the dynamics of earthquakes. In this framework, the oscillators of the network interact through an instantaneous impulsive coupling: whenever an oscillator fires, it sends out a pulse which instantaneously increments the state of the other oscillators by a constant value. There is an extensive literature on the subject, which investigates various model extensions, but only in the case of leaky integrate-and-fire oscillators. In contrast, the present dissertation addresses the study of other integrate-and-fire dynamics: general monotone integrate-and-fire dynamics and quadratic integrate-and-fire dynamics. The main contribution of the thesis highlights that the populations of oscillators exhibit a dichotomic collective behavior: either the oscillators achieve perfect synchrony (slow firing frequency) or the oscillators converge toward a phase-locked clustering configuration (fast firing frequency). The dichotomic behavior is established both for finite and infinite populations of oscillators, drawing a strong parallel between discrete-time systems in finite-dimensional spaces and continuous-time systems in infinite-dimensional spaces. The first part of the dissertation is dedicated to the study of monotone integrate-and-fire dynamics. We show that the dichotomic behavior of the oscillators results from the monotonicity property of the dynamics: the monotonicity property induces a global contraction property of the network, that forces the dichotomic behavior. Interestingly, the analysis emphasizes that the contraction property is captured through a 1-norm, instead of a (more common) quadratic norm. In the second part of the dissertation, we investigate the collective behavior of quadratic integrate-and-fire oscillators. Although the dynamics is not monotone, an “average” monotonicity property ensures that the collective behavior is still dichotomic. However, a global analysis of the dichotomic behavior is elusive and leads to a standing conjecture. A local stability analysis circumvents this issue and proves the dichotomic behavior in particular situations (small networks, weak coupling, etc.). Surprisingly, the local stability analysis shows that specific integrate-and-fire oscillators exhibit a non-dichotomic behavior, thereby suggesting that the dichotomic behavior is not a general feature of every network of pulse-coupled oscillators. The present thesis investigates the remarkable dichotomic behavior that emerges from networks of pulse-coupled integrate-and-fire oscillators, putting emphasis on the stability properties of these particular networks and developing theoretical results for the analysis of the corresponding dynamical systems. [less ▲]Detailed reference viewed: 86 (16 ULg) L'influence des pairs sur le développement des comportements normatifs et antisociaux chez l'adolescent délinquantMathys, Cécile Doctoral thesis (2011)Detailed reference viewed: 16 (3 ULg) Study of the ecology, population structure and dynamic of the macroalgae Codium elisabethae in Faial (Azores) with underwater visible imagery.Sirjacobs, Damien Doctoral thesis (2011)Codium elisabethae O.C. Schmidt is a dark green globose macroalgae isolating an internal sea water volume in a lumen. Codium elisabethae is endemic to the Macaronesian region and is very similar to Codium ... [more ▼]Codium elisabethae O.C. Schmidt is a dark green globose macroalgae isolating an internal sea water volume in a lumen. Codium elisabethae is endemic to the Macaronesian region and is very similar to Codium bursa C. Agardh whose distribution range spans the West-European, North-Western African and Mediterranean coasts and which was proposed as a potential indicator of coastal environmental changes based on the study of its ecology, revealing its long lifespan. Until recently, relatively little was known on Codium elisabethae as compared to the more widespread Codium bursa. To fill this gap, the present research aimed at producing an accurate description of the ecology and population dynamics of Codium elisabethae occupying the rocky shores of the Monte da Guia Special Area of Conservation (SAC)/Natura 2000 network (Faial, Azores). To achieve this, two reference sites were selected for long term monitoring: a sheltered no-go reserve exhibiting a dense Codium elisabethae population (Caldeirinhas), and a location experiencing more exposed conditions holding a sparser population (Ponta Furada). First, environmental conditions experimented by benthic organisms were extensively quantified and interpretated in regard to topographical particularities of each site. The study of reproduction dynamics showed a persistent summer fertility and an important vegetative reproduction. Important nutrient concentration ratio was found between the Codium elisabethae lumen water and surrounding sea water (mean ratios: nitrates: 5.7; ammonium: 3.4; phosphates: 3.1). In situ counting’s and size measurements revealed much higher densities of young recruits in the site of the Caldeirinhas (order of 20 ind/m²) than in the one of Ponta Furada (order of 1/m), for both summer and winter. Secondly, underwater visible imagery was exploited as an efficient and non-invasive alternative to classical in situ population estimation. Between August 2003 and November 2005, fifteen seabed photo coverages were collected by scuba-divers. Subsequent image processing consisted in mosaicing, interactive identification, and automatic change detection methods. This allowed quantifying the seasonal fluctuations of population structures (density, percentage cover and biomass) and of population dynamics (growth, recruitment, mortality and primary production). Chi-square tests of image-derived estimates and in situ measurements confirmed the validity of a centimeter precision for the estimation of population structure of individuals above 4 cm diameter. Important variability of population structure and density was observed within the sites at small spatial scales. Significant differences of population structure and dynamics parameters are demonstrated between two close-by but contrasting coastal habitats. Population density showed a sharp reduction in autumn 2003 and did not recover fully in spring and summer 2004. During the following year, population of the protected site maintained density and biomass, while at the exposed site population density dropped. In contrast with conclusions from earlier studies on the Azorian Codium elisabethae and on the Mediterranean Codium bursa, the present study revealed higher biomass (34 - 730 g dry wt.m-²), growth rates (up to 2.5 cm/month in summer) and primary production (0.53 – 11.5 g dry wt.m-².day-1), and demonstrated the seasonal fluctuations of these parameters for the studied Azorian Codium elisabethae population. The lifespan of Codium elisabethae was estimated to reach at least 7 years in the SAC of Monte da Guia based on an integration of average seasonal growth rates measured by imagery on extended population samples. This study demonstrates the high potential of registered underwater photomosaics time-series for long term surveys of macroalgae populations. This work provides also a strong framework to further developments and applicability to other species, which should be helpful to strengthen our current understanding of benthic ecosystem processes. [less ▲]Detailed reference viewed: 134 (37 ULg) Io's interaction with Jupiter's magnetosphereDols, Vincent Doctoral thesis (2011)Io, the innermost Galilean moon of Jupiter, is the most volcanic body of the solar system. This volcanism is responsible for a tenuous atmosphere composed mainly of S, O and SO2. This atmosphere is ... [more ▼]Io, the innermost Galilean moon of Jupiter, is the most volcanic body of the solar system. This volcanism is responsible for a tenuous atmosphere composed mainly of S, O and SO2. This atmosphere is constantly bombarded by the plasma that co-rotates with the magnetic field of Jupiter, producing new ions and perturbing locally the magnetic field. This local perturbation is responsible for auroral emissions in the atmosphere of Jupiter, at the foot of Io’s flux tube. The spacecraft Galileo made five flybys of Io between 1995 and 2001 at very low altitude (~100’s km) and made plasma and magnetic field measurements that reveal the complexity of Io’s interaction with Jupiter. Past studies have tackled the modeling of this interaction using different complementary approaches, each shedding a new light on the issue but each involving some simplifications. The MHD models (Linker et al., 1998) are based on an a priori parameterization of the ionization in the atmosphere, generally assuming spherical symmetry and a single atmospheric and plasma species (representative of O and S). They ignore the important effect of the cooling of electrons as well as the multi-species composition of both the plasma and the atmosphere. The two-fluid approach (Saur et al., 1999) computes precisely the ionization and collisions in the atmosphere of Io but make the assumption of a constant magnetic field, limiting the self-consistency of the model and potentially introducing large quantitative errors. We combine a multi-species chemistry model of the interaction that includes atomic and molecular species with a self-consistent Hall-MHD calculation of the flow and magnetic perturbation to model as self-consistently as possible the plasma variables along the different flybys of Io by the Galileo probe. [less ▲]Detailed reference viewed: 18 (4 ULg) MODELISATION DE L’ACTIVITE DES BACTERIES DU SOUFRE EN LAGUNAGEHarerimana, Casimir Doctoral thesis (2011)Detailed reference viewed: 54 (10 ULg) Signal transduction in photodynamic therapy-mediated cell deathCoupienne, Isabelle Doctoral thesis (2011)Les glioblastomes sont des tumeurs du cerveau comptant parmi les plus fréquentes et les plus agressives. En effet, l’espérance de vie médiane des patients est d’environ quinze mois après diagnostic ... [more ▼]Les glioblastomes sont des tumeurs du cerveau comptant parmi les plus fréquentes et les plus agressives. En effet, l’espérance de vie médiane des patients est d’environ quinze mois après diagnostic. Malgré d’intenses recherches et l’utilisation de traitements combinant la chirurgie, la radiothérapie et la chimiothérapie, le pronostic des patients n’a guère évolué depuis une vingtaine d’années. Ces tumeurs sont caractérisées par la présence de diverses altérations génétiques et, généralement, par une activation constitutive du facteur de transcription NF-κB. Étant un régulateur majeur de l’apoptose et de la survie cellulaire, ce facteur pourrait jour un rôle central dans la résistance des glioblastomes aux diverses thérapies. Au cours de ce travail, nous avons étudié les effets de l’inhibition du NF-κB sur la mort cellulaire des glioblastomes induite en réponse à un traitement par PDT, dont l’efficacité repose sur la production d’espèces réactives de l’oxygène suite à la présence simultanée d’un photosensibilisateur, de lumière et d’oxygène. Ainsi, nos résultats montrent que les cellules dans lesquelles le NF-κB est inhibé présentent une sensibilité accrue au traitement par rapport aux cellules non-inhibées. De plus, cette augmentation de mort cellulaire est majoritairement due à de la nécrose. Le traitement par PDT conduit également à l’apparition d’autophagie cytoprotectrice dont l’inhibition améliore l’efficacité du traitement. Nous nous sommes ensuite focalisés sur la mort par nécrose et avons démontré l’implication de la kinase RIP3 dans la mort nécrotique induite par PDT. Il est apparu que l’oxygène singulet produit au cours du traitement était à l’origine de la nécrose RIP3-dépendante. Cependant, les intermédiaires transductionnels et la manière dont le NF-κB exerce ses effets anti-nécrotiques demeurent encore inconnus. Enfin, afin de mieux comprendre le rôle joué par RIP3 dans la mort induite par PDT, nous avons utilisé la lignée d’ostéosarcome U2OS, déficiente en cette protéine, et au sein de laquelle nous en avons restauré l’expression. De manière surprenante, les cellules sauvages se sont révélées plus sensibles au traitement que les U2OS exprimant RIP3. De plus, la lignée RIP3-U2OS montre un taux d’apoptose supérieur à celui de son homologue sauvage. Cette divergence peut en partie s’expliquer par une induction d’autophagie plus importante au sein des RIP3-U2OS. Celle-ci, pouvant être un mécanisme pro-survie, peut leur conférer une protection contre la mort cellulaire en facilitant l’élimination des organelles endommagés. Enfin, nous avons déterminé que les cellules sauvages présentent un taux de nécrose plus important que les cellules RIP3-U2OS en réponse au traitement. Nos résultats ont dont permis de prouver (i) que l’inhibition du NF-κB améliorait la sensibilité des glioblastomes à la mort cellulaire induite par un traitement par 5-ALA-PDT, (ii) que celle-ci était, dans ce cas, majoritairement de la nécrose RIP3-dépendante et (iii) de mettre au jour un rôle pour RIP3 dans la régulation de l’apoptose et de l’autophagie induites par PDT. [less ▲]Detailed reference viewed: 24 (16 ULg) La résilience des banques libanaises : analyse de certains aspects de la gestion des risques dans le cadre de l'accord de BâleEl Khoury, Ghada Doctoral thesis (2011)Located in an environment of high uncertainty, supervisors in Lebanon have decided to comply with regulations issued by the Basel Accords and to monitor the new Basel Committee prudential framework. This ... [more ▼]Located in an environment of high uncertainty, supervisors in Lebanon have decided to comply with regulations issued by the Basel Accords and to monitor the new Basel Committee prudential framework. This thesis focuses on the Lebanese banking sector and on Basel II specific aspects in the Lebanese context. Four research areas are covered : 1. Evaluation of the capitalization level of Lebanese banks as required by Basel II prudential standards. 2. Lebanese sovereign risk analysis and its impact on the sustainability of banks through the measurement of probability of default of the Lebanese state on its Eurobonds denominated in U.S. dollars. 3. Examining the question of bank balance sheet procyclicality generated by the accounting and prudential framework, and by contextual factors specific to the resilience of the Lebanese banking sector. 4. Evaluation of the adaptation level of the Lebanese banking sector to new risk management approaches by estimating the probability that banks will well manage their risks. From a comparative analysis of the regulatory and economic capital, we found that 14 banks have a high economic capital relative to regulatory capital under Basel II in 2005. We also observed that the risks faced by Lebanese banks are primarily related to credit risk and sovereign risk in particular. Applying the valuation model of default risk, developed by Merrick (2001), and based on a review of scientific literature, we proposed a synthetic measure of credit risk of the Lebanese US dollar denominated Eurobonds. The results show that changes in the probability of default and recovery rates are explained by the trust vis-à-vis the market and state. Based on a review of the scientific literature, we have developed theories of economic fluctuations and financial instability. The analyses of procyclicality in the Lebanese context have shown that the factors leading to a balance sheet procyclicality in the Lebanese banking sector are atypical. We have also shown the resilience of the Lebanese banking sector to recent shocks and crises. Through a survey conducted between November 2009 and February 2010, we assessed the level of adaptation of the Lebanese banking sector to new risk management approaches. The results show that some banks have become more aware of the importance of developing proper risk management practices. Therefore, other banks remain in a precarious stage. [less ▲]Detailed reference viewed: 111 (5 ULg) Extension of the Liège Intranuclear Cascade Model to the 2-15 GeV Incident Energy RangePedoux, Sophie Doctoral thesis (2011)The Liège Intra-Nuclear Cascade model (INCL4) has been shown to be quite successful for the description of spallation reactions. However its validity domain is limited to an upper incident energy of ~2 ... [more ▼]The Liège Intra-Nuclear Cascade model (INCL4) has been shown to be quite successful for the description of spallation reactions. However its validity domain is limited to an upper incident energy of ~2 GeV, because inelastic elementary processes are restricted to the excitation and de-excitation of the Delta resonance. In this thesis, the INCL4 model is extended to higher incident energy. This is realised by including other inelastic elementary collisions, direct multipion production in elementary nucleon-nucleon and pion-nucleon collisions. This is somehow opposite to the usual extension to high energy of such models, as it is usually realised by including excitation of heavier baryonic resonances. Experimental data and isospin symmetry have been exploited in the implementation of multipion channels, but we could not avoid to introduce specific models for the energy-momentum and charge repartition on the final pions. The predictions of the modified model for production of protons, neutrons and charged pions by proton and pion beams off nuclei are compared with experimental data. A short study on nuclear fragmentation is also presented. [less ▲]Detailed reference viewed: 31 (5 ULg) Bouncing droplets, the role of deformationsTerwagne, Denis Doctoral thesis (2011)Nowadays, innovative applications such as "lab-on-a-chip", micro-reactors or biological chips are developed for industry, biology or medicine. Capillary issues are encountered which are not yet fully ... [more ▼]Nowadays, innovative applications such as "lab-on-a-chip", micro-reactors or biological chips are developed for industry, biology or medicine. Capillary issues are encountered which are not yet fully understood. It is therefore essential to open up ways to manipulate tiny amounts of liquid in order to mix them, encapsulate them or to create emulsions. The bouncing droplets on an oscillating liquid interface allow their manipulation. Indeed, under certain conditions, droplets can bounce indefinitely on a bath surface as long as the squeezed air film which separates the drop from the bath is renewed at each bounce. We chose to study deformable droplets on a non-deformable bath. The droplets are deformable because they are large or made of a low viscous oil, the liquid of the bath being highly viscous silicone oil. We investigated how the deforma- tions, the stability and the trajectories of the droplets depends on the forcing parameters such as the frequency and the amplitude of the oscillation. We also studied the possibility of mixing and emulsifying droplets on the bath. Finally, we showed the effect of the deformation of the bath on these bouncing droplets and studied the trajectories of walking droplets [1] which are used as a model for quantum-like particles [2-5]. In this manuscript, we reported an exploration of the droplets behavior as a function of the ability of the bath and/or the droplet to deform. Depending on the forcing frequency, specific deformation modes are excited on the bouncing droplets. We used these modes to rationalize their bouncing stability and to create double emulsions in a compound droplet. Then, we determined numerically the complex bifurcation diagrams of the trajectories of a bouncing droplet thanks to a model based on a spring. On a low viscous bath, we evidenced the importance of its deformation. We showed that a walker exists as soon as the droplet experiences, once every two oscillation periods, a jump high enough to trigger a Faraday wave. As a consequence, we have to take the bouncing droplets into account when looking for an alternative way to manipulate them or as a model of quantum-like particles. The bouncing droplets still exhibit lots of intriguing behaviors which have yet to be explained. They can therefore remain the focus of future works. [less ▲]Detailed reference viewed: 67 (18 ULg) Impact des oiseaux granivores sur les céréales les plus cultivées au Burundi: cas du rizNasasagare, Régine Pacis Doctoral thesis (2011)Detailed reference viewed: 41 (4 ULg) Application de la spectroscopie Raman à l’analyse de colorants sur fibres de coton dans le contexte de la criminalistiqueLepot, Laurent Doctoral thesis (2011)Forensic examination of textile fibres is based on fibre morphology and on fibre material and dyes characterization. Cotton is the most frequently used fibre in textiles but also the most encountered in ... [more ▼]Forensic examination of textile fibres is based on fibre morphology and on fibre material and dyes characterization. Cotton is the most frequently used fibre in textiles but also the most encountered in casework. While man-made fibres show various morphologies and materials, cotton is a natural cellulosic fibre with constant morphology. Cotton fibres examination can consequently be summarized in the characterization of fibre dyes. However forensic needs require non-destructive, fast and sensitive techniques. For fibres microspectrophotometry (MSP) is the commonly used technique and the obtained UV-Vis absorption spectrum reflects dyes used to colour the fibre. Any other technique suitable for dye characterization is thus helpful to reinforce MSP results on cotton fibres. Raman spectroscopy is a fast non-destructive technique, easy to integrate into the fibre analytical sequence without any additional sample preparation. Moreover it provides specific molecular information and seems convenient for the study of coloured molecules. This work allowed to demonstrate the potential of the technique in dyed cotton fibres examination through the characterization of pure dyes but also the ability to detect different components in dye mixtures. In order to help dye identification spectral databases were built using Raman spectra collected in the present work. Unfortunately such a database will never be exhaustive and the identification of an unknown dye would be compromised. An interesting option is to identify the general chemical class of the unknown dye, especially to evaluate its rarity. The recognition of some dye chemical classes has been made by the mean of characteristic peaks but this method remains somewhat subjective. This subjectivity can be bypassed using chemometric techniques; they are able to predict chemical class membership on the basis of Raman specific information. Some experiments have been performed on Raman spectra using PCA models and the SIMCA classification tool. [less ▲]Detailed reference viewed: 121 (27 ULg) Impacts des changements climatiques passés et présents sur la génétique et la démographie du Cincle plongeur (Cinclus cinclus)Hourlay, Frederic Doctoral thesis (2011)Climate change is emerging as the greatest threat to natural communities in many, if not most, of the world’s ecosystems in coming decades. Numerous studies have revealed present and probable future ... [more ▼]Climate change is emerging as the greatest threat to natural communities in many, if not most, of the world’s ecosystems in coming decades. Numerous studies have revealed present and probable future consequences that climate change will have on many animal and vegetal species. According to these studies, birds could be affected, mostly negatively, in various ways : distribution, abundance, phenology, ethology ... The purpose of this work is to determine how the White-throated Dipper (Cinclus cinclus), a Palearctic, temperate, passerine bird that is exclusively associated with flowing water, reacted to the climate changes that occurred during the Pleistocene, and how climate change currently affects this species : - For this purpose, we conducted a phylogeographic study : we analysed three fragments of mtDNA (i.e. fragments coding for cytochrome b, ND2 and domains II and III of the controle region) from 106 tissue samples originating from 24 dipper populations, mostly located in the Western Palearctic. - The second part of this work consisted in analysing ringing recoveries and nest-boxes frequentation from a dippers population settled on the river Syre and its tributaries (Luxemburg) and followed from 1979 to 2001. Populations census were also conducted on different water courses in Luxemburg, in order to determine dipper habitat preferences. 1. Phylogeography of the dipper in the Western Palearctic region In spite of a low genetic variability, the results of our phylogeographic study reveal a complex phylogeographic structure for this species with at least five distinct lineages for the Western Palearctic region. As for many species of the Western Palearctic fauna and flora, this genetic structure is probably linked to the isolation of populations in different southern refuges during glacial periods. Furthermore, the isolation of populations in Scandinavia and/or Eastern regions, but also in Morocco and probably in Corsica, was accentuated by ecological and biogeographic barriers during Quaternary interglacial periods. During glacial periods, Italy, Sicily and the Balkano-Carpathian region acted as major refuge zones for the dipper. At the end of the last ice age, Western Europe was repopulated by dippers from a refuge located in Italy and, probably, South-East France, while Eastern Europe was recolonised by Balkano-Carpathian birds. A large contact zone between these two lineages was evidenced and extends from Luxembourg to Hungary. Finally, our results indicate the need to clarify the taxonomic status of the dipper, especially concerning the European subspecies whose validity appears uncertain. 2. Dipper demography – Influence of climate change and other anthropic pertubations Results obtained from the analysis of demographic and morphologic variables of the Luxemburger population are in agreement with results obtained from other European populations. Differences observed between these populations are mostly due to climate and habitat quality differences. However, other factors could also partly explain these differences. As for other places in Europe, nest boxes installation dramatically increased dippers population size on the river Syre. Our results also suggest that the installation of nest boxes could influence some demographic and morphologic variables, probably as a result of population increase. But, above all, our results show how temperatures and precipitations affect these variables, and particularly laying dates. Climatic changes that occurred during the last decades provoked earlier laying dates. Whereas clutch size and nest size remained unchanged, the Luxemburger population size decreased during the same period, as observed for other European populations. The main cause to this decrease should be an increase of environmental instability inducing notably a decrease of food ressources for dippers. As a result, we observed a significant decrease of females body weight during this period. Climate change will also probably have a serious impact on dipper genetic diversity, leading to the disappearance of the most southern populations and eventually of certain genetic clades. The results obtained concerning the taxonomic status of the dipper and its demography could be useful in the framework of a conservation program, if necessary. In this perspective, the development of habitat suitability prediction tools, as the one we developed, could also be very helpful. [less ▲]Detailed reference viewed: 34 (8 ULg) Study of the Cape Ghir upwelling filament using variational data analysis and regional numerical modelTroupin, Charles Doctoral thesis (2011)Aim: Upwelling filaments are shallow, elongated structures of cool waters often visible in the regions of coastal upwelling. The present thesis aims to improve our knowledge on the mechanisms responsible ... [more ▼]Aim: Upwelling filaments are shallow, elongated structures of cool waters often visible in the regions of coastal upwelling. The present thesis aims to improve our knowledge on the mechanisms responsible for the generation of filaments. Location: the study is centered on the Canary Current Upwelling system, located off northwest Africa, in particular around Cape Ghir (30°38'N, 9°53'W), where these filaments are frequently observed. Methods: - We compiled historical in situ data to build a high-resolution climatology of temperature and salinity in the region of interest using the Data Interpolating Variational Analysis (\diva) method. - We ran the experiments with the numerical model ROMS to investigate the processes responsible for the filament generation. - We collected in situ measurements during a cruise in August-September 2009, in the frame of the CAIBEX project, in the filament area and analyzed them to get a detailed description of the Cape Ghir filament, its variability and its biogeochemical characteristics. - We computed anomalies of several variables with respect to a long-term mean to examine the time-evolution of the Canary Current Upwelling system. Results: The climatology showed improvements with respect to existing products, especially in the coastal area, and was a valuable asset to provide initial and boundary conditions for the numerical model. The results of the simulations underlined the role of the wind in the filament generation and confirmed our assumption of a mechanism based on the potential vorticity balance. Preliminary analysis of the cruise data allowed us to characterize the filament physical and biological properties, in particular we observed the signal of a subsurface (at a depth of 300~m) anticyclonic eddy on the northern flank of the filament, also present in the numerical model outputs. Anomalies for the year 2010 revealed a widespread warming over the tropical and subtropical Atlantic Ocean and a diminution of the upwelling activity. We attributed these anomalies to a weakening of the winds, itself related to a strongly negative North Atlantic Oscillation (NAO) index. [less ▲]Detailed reference viewed: 84 (26 ULg) Unveiling the internal structure and evolution of massive stars through their pulsation modesGodart, Mélanie Doctoral thesis (2011)Stars in the night sky are not as quiet as they seem. A human being wandering on Earth few billions years ago would have seen a different night sky, with different stars forming different constellations ... [more ▼]Stars in the night sky are not as quiet as they seem. A human being wandering on Earth few billions years ago would have seen a different night sky, with different stars forming different constellations. Moving forward in time, he would have been the witness of stellar evolution as some stars would have suddenly shined while others disappeared forever. Hard to realize at a time scale of human life, stars are born, evolve, and die in a limited lifetime which can last only a few million years for the most massive to trillion years for the less massive. Fortunately, it is not necessary to wait that long to study the formation and evolution of stars. Stellar evolution can be studied on shorter time scales, on thousands of stars, at various evolutionary stages. This is of great importance as stars shape the Universe and produce the chemical elements at the origin of life. Probing the internal structure of stars is however very challenging due to the opacity barrier of their superficial layers. One way to get around this issue is to study and interpret stellar pulsations. As seismologists extract information about Earth interior trough the study of earthquakes, asteroseismologists can study the internal structure of stars by studying their oscillations. In this thesis, this technique is used to study the internal structure and evolution of massive stars which are at least eight times more massive than our Sun and which have a spectral type between O and B. The first part of this work is devoted to the determination of the $\kappa$-mechanism instability domains for massive stars. In order to extend the computations to the post-main sequence phase of evolution, we develop a numerical technique in which the non-adiabatic computations for the stellar core are made, independently than for the envelope, within the quasi-adiabatic and the asymptotic treatment. In a second step, we investigate the pulsations modes in O main sequence stars and in B post-main sequence stars. The presence of g-modes in post-main sequence stars is closely related to the internal structure of the star and we study the effects of several physical factors on the occurrence of these modes. Finally, the last part of this work is dedicated to the characterization of strange mode pulsations. In particular, we focus on strange modes having an adiabatic counterpart, which are trapped into a superficial cavity. The effect of the model atmosphere on the excitation is investigated in addition to the characterization of their eigenfunctions. [less ▲]Detailed reference viewed: 24 (8 ULg) Narrateur, personnage et leceur virtuel: vers une méthode d'analyse intra-relationnelleGoin, Emilie Master's dissertation (2011)Dans l'étude d'un possible dialogisme entre les instances internes au récit que sont le narrateur, le personnage et le lecteur virtuel (soit l'instance de lecture présupposée par le texte), ce travail ... [more ▼]Dans l'étude d'un possible dialogisme entre les instances internes au récit que sont le narrateur, le personnage et le lecteur virtuel (soit l'instance de lecture présupposée par le texte), ce travail pose notamment les questions des subjectivèmes, de leur assemblage en point de vue et des articulations de points de vue hétérogènes: comment peut-on les repérer, identifier différentes formes d'assemblage/articulation et déterminer leur force illocutoire? [less ▲]Detailed reference viewed: 71 (8 ULg) Des indications sur un détour. Les rapports entre Althusser et SpinozaMancuso, Eva Master's dissertation (2011)Detailed reference viewed: 76 (11 ULg) Caractérisation des effets de température dans la zone endommagée autour de tunnels de stockage de déchets nucléaires dans des roches argileusesDizier, Arnaud Doctoral thesis (2011)La solution du stockage des déchets nucléaires de haute activité et de longue durée de vie dans les couches argileuses profondes comporte de nombreuses incertitudes. Pour combler celles-ci de nombreux ... [more ▼]La solution du stockage des déchets nucléaires de haute activité et de longue durée de vie dans les couches argileuses profondes comporte de nombreuses incertitudes. Pour combler celles-ci de nombreux projets européens sont réalisés de façon à les minimiser. Le projet TIMODAZ (Thermal Impact On the Damaged Zone Around a Radioactive Waste Disposal in Clay Host Rocks) étudie l'influence de la température sur la zone endommagée. Cette zone correspond à une zone soumise à la redistribution des contraintes lors de l'excavation constituant un lieu de développement de micro et macro fractures. Cet endommagement mécanique est complété par un endommagement thermique lors de la pose des canisters qui vont émettre de la chaleur durant des milliers d'années et donc provoquer une augmentation de la température du massif argileux. Cette élévation de température de l'argile peut faire apparaitre des déformations plastiques thermiques de contraction. Cette nouvelle plasticité peut contribuer au développement de la zone endommagée. L'objectif de ce travail est donc de caractériser la zone endommagée autour des tunnels souterrains, construits dans l'Argile de Boom, soumis à des élévations de température induites par les déchets nucléaires. Durant ce travail, une loi de comportement thermo-mécanique est implémentée. Celle-ci se base sur un "modèle à chapeau" étendu à la thermo-plasticité. Ce modèle comprend la combinaison d'un modèle à frottement interne, d'un critère Cam-Clay et d'un critère de rupture à la traction. Ce modèle est étendu à la température et en particulier à la thermo-plasticité en considérant les travaux de Sultan. Les paramètres thermo-hydro-mécaniques de l'Argile de Boom sont identifiés et servent à la modélisation d'expériences de laboratoire et in situ. Ces expériences consistent en outres en un cylindre creux, en l'expérience de chauffage ATLASIII et en l'expérience à grande échelle PRACLAY. Ces trois expériences ont pour objectif d'étudier l'Argile de Boom d'une petite échelle à une plus grande représentative du massif argileux. L'étude du comportement dans la zone élastique et plastique est également prise en compte via ces différentes expériences. Les résultats, avec différentes lois de comportement, montrent que l'influence de la thermo-plasticité est faible mais non négligeable vis-à-vis des déformations déviatoriques engendrées par l'excavation. [less ▲]Detailed reference viewed: 87 (10 ULg) InSAR Applied to the Study of Active Volcanic and Seismic Areas in AfricaWauthier, Christelle Doctoral thesis (2011)Two active volcanic areas situated in immature portions of the East African Rift System (EARS): the Lake Kivu (Dem. Rep. of Congo) and Lake Natron (Tanzania) regions, which are located in the western and ... [more ▼]Two active volcanic areas situated in immature portions of the East African Rift System (EARS): the Lake Kivu (Dem. Rep. of Congo) and Lake Natron (Tanzania) regions, which are located in the western and eastern branch, respectively, are still poorly known. Both areas indeed lack of ground-based networks, due to security problems or difficult field accessibility. The Lake Kivu area includes two volcanoes erupting frequently: the Nyamulagira and Nyiragongo volcanoes. The SAR database covering these volcanoes in- cludes data from JERS, ERS-1&2, ENVISAT, ALOS, RADARSAT-1&2 satellites back from year 1996. SAR Interferometry (InSAR) is thus applied to study the ground de- formations. MT-InSAR approaches, such as the ”‘StaMPS”’ method, are used to give us new complementary information to better constrain the previous established eruption models, or gain new insights on eruptions missed by the conventional InSAR, as well as on magmatic and tectonic activity. When enough constrains are available, the ground displacements are modeled using a 3D-Mixed Boundary Elements Method combined with a neighborhood algorithm. Hence, the 1996, 2002, 2004 and 2010 eruptions of Nyamu- lagira are modeled. The modeling results, coupled with the StaMPS MT-InSAR results, bring new insights concerning the magma plumbing system of this poorly known volcano and its eruptive mechanisms. The collapse of the eastern flank of Nyamulagira, along the NNW-trend fractures network linking Nyamulagira and Nyiragongo volcanoes, can also be identified. InSAR also captures the ground displacements associated with the January 2002 Nyiragongo eruption. The modeling of this major event evidences a deep magma intrusion beneath the Lake Kivu. Such intrusions should be taken into account for hazard assessment. The magma could indeed finds its way to the Lake Kivu floor, as evidenced by the presence of several old phreato-magmatic cones, and causes a lake overturn. The low dikes overpressures found in the North Kivu and Lake Natron areas indicate that, although the rift is considered as immature, the rift extension is driven by the supply of magma from depth, rather than by the tectonics. A new criterion to identify the rifting stage is found to be the stress state. In the southern part of the rift, tectonic activity dominates, indicating that the tectonics is probably driving the rift opening there. [less ▲]Detailed reference viewed: 71 (6 ULg) Dynamique des transactions foncières et vulnérabilité rurale au Niger : cas des communes rurales de Tchadoua et YaouriLawali Mani, Sitou Doctoral thesis (2011)Summary In Niger, agriculture is the principal activity of the rural populations. Unfortunately the access to the land becomes very difficult to the farmers in the center-south of the country. This area ... [more ▼]Summary In Niger, agriculture is the principal activity of the rural populations. Unfortunately the access to the land becomes very difficult to the farmers in the center-south of the country. This area is confronted to the space saturation and the emergence of the land transactions whose causes, process and impacts on the agricultural households are little known. The study undertaken in the rural municipality of Tchadoua and Yaouri aimed at analyzing the dynamics of the land transactions in bond with the rural vulnerability in terms of the stakes of access and management of the grounds, but also their securisation. The problems were studied with a multidisciplinary approach. The analyses (quantitative and qualitative) were carried out on the basis of the data collected in the village areas of Maijanguero and Gomba through cards of investigations and semi-structured interviews with a sample of 30% of the households. We also used participatory observations of agricultural practices and consultation of different sources of documentation. Administration and others authorities have been also interviewed aswel as members of the land commissions and the intermediaries of the transactions. The results obtained show that the problem of access and management of the land in these agricultural areas is an important concern for rural producers. The land blocking due to the strong demographic pressure and the increase of economic stakes (crop rent) influence the excessive parceling out of the grounds and the individualization of the farms. This individualization supports consequently, the emergence of the commercial land speculations for the profit of the economic operators installed from now in logic of monopolization of grounds. The purchase, the pledge and the lease constitute the principal access modes to the ground instead of old forms of solidarity (gift, loan). Also, the new agrarian initiatives of assistance appear and take part in the improvement of the socio-economic conditions of the rural households. The results also made it possible to highlight a diversity of trajectories of the exploitations. The land ‘’monetarisation’’ influenced strongly the land management and reinforced the exclusion of the vulnerable groups. The strong changes of technical transformation and farming system are observed. It as revealed as the land accumulation or ‘’décapitalisation’’ depends of the type of farm, its strategy and its revenue. Indeed, three tendencies become apparent from the trajectories: great manufacturing units with dominant commercial accumulate land, use the hired labor work and araw cash crop (souchet); a strong land ‘’decapitalisation’’ at the extremely vulnerable and without viable strategy of adaptation in the long term. Lastly, the small farm witch made a diversification and a strong intensification, and there resist to the multiple attempts of land spoliation. These last constitute a model of stable and durable farm whose strategy is based primarily on the agricultural intensification through effective and less expensive agroforestry practices to increase their production and their land capital. The informel and discrete character of land transactions and the networks of intermediation by which are negotiated the land sales accentuate the land insecurity and contribute to increase the land prices. The analysis of the securisation practices of the land rights proves that legal formalization though timid, reduced considerably the frequency of the rural conflicts and offers agricultural opportunities of investments. However, the land commissions encounter difficulties which, slow down the generalization of the legal formalization of transactions. All things considered, the land problem remains a central stake of development thus, the securisation of the land rights of the rural poor must be a priority of the priorities to reach a durable food safety. It is thus urgent to make the land commissions more operational in their giving the means of operation in order to ensure a broad diffusion of the procedures of formalization for more impact and also encouraging the producers through small subsidies to practice the carrying agri-environmental measurements. [less ▲]Detailed reference viewed: 83 (20 ULg)