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See detailDevelopment of inversion techniques in Asteroseismology
Buldgen, Gaël ULg

Doctoral thesis (2017)

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See detailAdaptive capacity assessment of damselfishes (Pomacentridae)
Gajdzik, Laura ULg

Doctoral thesis (2017)

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See detailMagneto-optical investigation of superconducting hybrid structures
Brisbois, Jérémy ULg

Doctoral thesis (2017)

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See detailL'abandon de sanctuaires et le transfert de cultes en Grèce antique
Palamidis, Alaya ULg

Doctoral thesis (2017)

Dans la Grèce antique, les sanctuaires anciens comme les sanctuaires nouvellement fondés étaient censés continuer à être fréquentés indéfiniment. Cependant, ce n’était pas le cas de tous les lieux de ... [more ▼]

Dans la Grèce antique, les sanctuaires anciens comme les sanctuaires nouvellement fondés étaient censés continuer à être fréquentés indéfiniment. Cependant, ce n’était pas le cas de tous les lieux de culte: certains pouvaient être abandonnés, de même que les divinités qui y étaient honorées, tandis que d’autres divinités continuaient à être honorées à un emplacement différent. Ce travail vise en premier lieu à analyser les sources littéraires, épigraphiques et surtout archéologiques qui nous renseignent sur des tels abandons de sanctuaires et transferts de cultes. L’étude de deux types de déplacements de population, les synécismes et les métécismes, au cours desquels de tels abandons et transferts sont documentés, permet par la suite de réfléchir notamment aux raisons qui expliquent l’abandon de certains sanctuaires plutôt que d’autres. L’analyse des sources disponibles suggère que ni les abandons de sanctuaires, ni les transferts de culte n’étaient considérés comme la transgression d’une norme tacite ou orale et que ces phénomènes sont beaucoup plus courants que ce qui est généralement supposé. [less ▲]

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See detailMultifunctional Polyelectrolytes Bearing Pendant Catechol / Quinone for Energy and Environmental Applications
Patil, Nagaraj ULg

Doctoral thesis (2017)

The discovery of 3,4-dihydroxyphenyl-L-alanine (L-DOPA), a catechol-functionalized amino acid as major component in mussel adhesion proteins, has triggered enormous interest in mussel-mimetic adhesives ... [more ▼]

The discovery of 3,4-dihydroxyphenyl-L-alanine (L-DOPA), a catechol-functionalized amino acid as major component in mussel adhesion proteins, has triggered enormous interest in mussel-mimetic adhesives. The design of innovative bioinspired polymers-containing catechols has rapidly gained widespread utility in the (bio)material field, ascribed to the versatility of the catechol chemistry that allows anchoring (bio)polymers, biomolecules, nanoparticles (metals and metal oxides) and other compounds onto almost any kind of surfaces without any pre-treatment. Amongst the various synthetic protocols to incorporate catechol functionalities into (bio)polymers, the radical polymerization of catechol-bearing vinyl monomers in their protected form has proven to be a versatile technique to impart intrinsic physico–chemical properties of the catechol pendants to polymers after appropriate deprotection. Importantly, the scope of applications of catechol-bearing polymers can potentially be drastically increased by developing controlled radical polymerization (CRP) techniques of their protected vinyl monomers. Indeed, these techniques will enable to precisely design the polymer with the appropriate structure, molar mass and functionality that fit at best the target application. When this thesis started in 2013, only very limited examples of functional catechol-bearing polymers prepared by CRP were reported. The aim of this PhD thesis was to develop well-defined innovative catechol-containing (co)polymers that find applications in energy storage and environmental fields by employing function-oriented macromolecular engineering approaches. In this work, numerous catechol-protected monomers have been prepared and their CRP investigated to afford well-defined (co)polymers with controlled and tunable molar masses, compositions, functionalities, and architectures (homopolymers, statistical and block copolymers). The potential of these innovative catechol-containing (co)polymers was then explored for applications in energy storage (as active-material in lithium-ion half-cells) and environment (as protein fouling/antifouling coatings). [less ▲]

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See detailSearch for the signatures of mass-exchange episodes in massive binaries
Raucq, Françoise ULg

Doctoral thesis (2017)

Massive stars are known for their crucial role in our Universe, through their extreme stellar parameters, leading to a strong impact on their environment. However, there remain numbers of unanswered ... [more ▼]

Massive stars are known for their crucial role in our Universe, through their extreme stellar parameters, leading to a strong impact on their environment. However, there remain numbers of unanswered questions concerning the exact processes of their formation, their stability or the processes driving their strong stellar winds. In the context of this thesis work, we adress one of the most interesting of their peculiarities: their tendency to be part of binary of higher multiplicity systems. Whilst this multiplicity does help to solve some open issues by allowing us to study some of the fundamental properties of the stars, such as their minimum masses and radii as well as their stellar luminosities, it can also lead to interactions between the components of a system, which affect the subsequent evolution of the stars and give rise to additional open questions on the processes in place in such systems. Among the possible interactions taking place within close binary systems is the possibility of a transfer of mass and kinetic momentum through a Roche lobe overflow. This process has a huge impact on the subsequent evolution of both components and many aspects of this phenomenon are not well understood yet. The present work is devoted to the search for the signatures of such past mass-exchange episodes in a sample of four short-period massive multiple systems: HD 149404, LSS 3074, HD 17505 and HD 206267. We determined a new orbital solution for three of them. We then used phase-resolved spectroscopy to perform the spectral disentangling of the optical spectra of the components. The spectral disentangling is a mathematical tool which allows to separate the contributions of both components to the observed spectra of a system. We then analysed the reconstructed spectra with the CMFGEN atmosphere code to determine stellar parameters, such as the effective temperatures and surface gravities, and to constrain the surface chemical composition of each component. The first two parts of this dissertation are dedicated to the scientific background and the description of the numerical tools and methods used in this work. The third part presents our studies of the selected massive systems. We confirmed that the hypothesis of a past Roche lobe overflow episode is most plausible to explain the observed properties of the components of HD 149404. Photometric data permitted us to confirm that LSS 3074 is in an overcontact configuration, and a combined analysis with spectroscopy showed that the system has lost a significant fraction of its mass to its surroundings. We proposed several possible evolutionary pathways involving a Roche lobe overflow process to explain the current parameters of its components. We found no evidence of past mass-transfer episodes in the spectra of HD 17505 and showed that the current properties of its components can be explained by single star evolutionary models including rotational mixing. We found clues of binary interactions in the spectra of HD 206267, but suggested that the system did not experience a complete Roche lobe overflow episode at this stage of its evolution. [less ▲]

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See detailQuality evaluation of peach chips and anticancer activity of pectin extracted from chips dehydrated by explosion puffing drying
Lyu, Jian ULg

Doctoral thesis (2017)

The objectives of this research are to discriminate the overall quality level of peach and nectarine chips prepared by explosion puffing drying (EPD), determine the changes of texture and water soluble ... [more ▼]

The objectives of this research are to discriminate the overall quality level of peach and nectarine chips prepared by explosion puffing drying (EPD), determine the changes of texture and water soluble pectin (WSP) during EPD processing and study the anticancer activity of WSP on malignant mesothelioma (MM). Principle component analysis (PCA), Analytic hierarchy process (AHP), K-mean cluster and Discriminant analysis (DA) are used to distinguish the overall quality level of peach and nectarine chips and get the characteristic evaluation indicators, which of them (e. g. rehydration ratio and expansion ratio) are corresponding to texture properties of dehydrated products. Additionally, biochemical changes of the cell wall (e. g. pectin) are also related to texture changes. The investigate on the changes of texture and WSP at different stages of EPD processing in which osmotic dehydration (OD) was used as the pretreatment, show that OD with the appropriated concentration can improve the texture quality of dried products. The drying processing causes the degradation and structure modification of WSP, which can induce apoptosis in MM cells. EPD technology can be carried out as a potential pathway on modification of pectin, which may contribute to the development of a potential therapy against MM. [less ▲]

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See detailRhétorique du détournement vidéoludique. Le cas de Pokémon
Barnabé, Fanny ULg

Doctoral thesis (2017)

La présente recherche se situe au croisement de plusieurs traditions disciplinaires – les sciences du jeu, les études littéraires, la rhétorique, les cultural studies – et de plusieurs objets – le jeu, le ... [more ▼]

La présente recherche se situe au croisement de plusieurs traditions disciplinaires – les sciences du jeu, les études littéraires, la rhétorique, les cultural studies – et de plusieurs objets – le jeu, le détournement, les fanfictions, machinimas, speedruns, let’s plays et mods. Sans prétendre opérer ici leur synthèse ou leur conciliation, nous tenterons de dégager, entre ces différents domaines, de nouvelles ouvertures : nous montrerons, en circulant parmi eux, qu’ils sont pris dans des tensions, des dynamiques, des questionnements similaires et, surtout, centraux pour la compréhension de la culture populaire contemporaine. Plusieurs objectifs nous animent : définir le détournement et, à travers lui, éclairer sous un autre jour le fonctionnement du jeu ; développer un métadiscours à même de soutenir l’analyse des œuvres produites par les joueurs ; enfin, par la même occasion, défendre l’intérêt d’étudier de près ces œuvres amateurs, trop souvent délaissées par la recherche au profit des pratiques, et qui sont pourtant des épicentres essentiels autour desquels se développent les cultures ludiques. La poursuite de ces objectifs, toutefois, ne va pas sans soulever des questions complexes, qui traversent toute la thèse : quels parallèles et quelle frontière établir entre le détournement et le jeu ? Comment une œuvre est-elle reconnue, étiquetée, classée comme un détournement ? Qu’est-ce au juste qu’une œuvre dans un domaine où l’intertextualité, la reprise, la réinterprétation sont des normes ? Avec quels outils décrire les formes du détournement, et qu’ont en commun les genres disparates regroupés sous cette dénomination ? Nous traiterons ces diverses interrogations en deux temps. La première partie de la thèse, qui comporte deux sous-sections, en constituera le socle théorique : un premier chapitre y aborde les relations intimes entre jeu et détournement, tout en resituant notre recherche dans les différents champs qu’elle fait se croiser ; le second chapitre s’attache à la constitution d’un cadre métadiscursif inspiré de la rhétorique, visant à définir ce que pourraient être des « figures » du détournement vidéoludique. La deuxième partie, plus analytique, servira d’application au cadre précédemment construit, en montrant son utilité sur des études d’œuvres concrètes. Celles-ci sont réparties en trois grandes catégories : les détournements par le play (let’s plays, speedruns, tool-assisted speedruns et machinimas), les détournements du game (fanfictions et mods) et les recontextualisations (« Twitch plays… »). Par ailleurs, en guise de fil conducteur, toutes ces œuvres – de formes et de genres variés – auront pour point commun essentiel d’être dérivées d’un même univers fictionnel : celui de la licence Pokémon. [less ▲]

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See detailLes pathologies intestinales chirurgicales chez le cheval: activation neutrophilique, pronostic et complications postopératoires
Salciccia, Alexandra ULg

Doctoral thesis (2017)

Postoperative complications after colic surgery in horses remain of major concern as they are associated with non-negligible mortality rates. Many of these postoperative complications have an important ... [more ▼]

Postoperative complications after colic surgery in horses remain of major concern as they are associated with non-negligible mortality rates. Many of these postoperative complications have an important inflammatory component involving leukocytes, and particularly neutrophils, which represent the majority of granulocytes. Activated neutrophils produce reactive oxygen species and release inflammatory mediators and oxidative and proteolytic enzymes such as myeloperoxidase and elastase, which in turn will exacerbate pre-existing tissue lesions. This cascade of events will lead to the systemic inflammatory response syndrome. In an effort to improve the understanding of the systemic inflammatory reaction that follows colic surgery in horses, we described the time-trends of blood leukocytes and granulocytes counts and plasma myeloperoxidase and elastase concentrations during the perioperative period. Globally, survivor horses presented curves of blood leukocytes and granulocytes counts evolution lower and curve of evolution of plasma myeloperoxidase concentrations higher than those of non-survivor horses. These findings confirm the major influence of the inflammatory reaction on patient survival and allowed us to determine a prognostic value of blood leukocytes counts, a parameter easily available and routinely used in the aftercare of horses undergoing a colic surgery. We showed that in our population, non-survivor horses were more likely to have at least one blood leukocyte count inferior or equal to 3.9×10³/mm³ between 28 and 60 hours after surgery than survivor horses. Our following research, based on clinical studies, were directly or indirectly related to 2 common postoperative complications: incisional complications and ileus. In a study evaluating more than 600 exploratory laparotomies for colic, we showed that short laparotomy incisions, partially closed with interrupted vertical mattress sutures on the linea alba, and protected and supported by an abdominal bandage applied before the recovery from anaesthesia were associated with relatively low incisional complication and infection rates. These rates were respectively 9,52% and 5,31% after a single laparotomy and respectively 33,33% and 26,67% after repeat laparotomy. Bandage related complications occurred rarely. Risk factors of an incisional complication or infection in our population were prolonged anaesthesia duration, performing an enterotomy and postoperative intravenous lidocaine administration. The knowledge of these elements will certainly contribute to reduce the incidence of these complications in the future. Transabdominal ultrasonography of the small intestine is frequently used to diagnose and monitor a postoperative ileus. In order to improve the interpretation of ultrasonographic images after surgery, we determined the influence of general anaesthesia on these images. Using a protocol including horses anaesthetised for non-abdominal surgeries, we showed that although anaesthesia induces a physiologic ileus of short duration, expressed by a decreased of borborygmi without abdominal discomfort, its effects on the ultrasonographic images of the small intestine consisted mainly of a temporary increase (less than 12 hours) of the jejunal visualisation and diameter (with most of the observations remaining in the normal range) without thickening of the intestinal wall. Therefore the effects of general anaesthesia on ultrasonographic images of the small intestine can be distinguished from those of a pathological process. Our last study, including sound horses revealed that lidocaine, a molecule frequently used for treatment of postoperative ileus, may have a mild hypotensive effect on the arterial blood pressure and a mild prokinetic effect on the duodenum. Nevertheless, these results, original about the hypotensive effect, and controverted about the prokinetic effect, need to be confirmed in longer and larger studies. Our work has allowed us to bring some new elements leading to the improvement of our understanding of inflammatory processes related to the neutrophilic activation during the perioperative period of colic horses. Despite the improvement of methods of prevention, detection and treatment of postoperative complications, prognoses after this type of surgery still need to be enhanced. It seems that a huge work remains to be done to precisely determine the effects of various treatments, such as lidocaine. Numerous perspectives appear in the search of new molecules aiming to reduce the inflammatory reaction and to prevent or treat postoperative complications of horses undergoing colic surgery. [less ▲]

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See detailStatistical analysis of areal quantities in the brain through permutation tests
Winkler, Anderson ULg

Doctoral thesis (2017)

In this thesis we demonstrate that direct measurement and comparison across subjects of the surface area of the cerebral cortex at a fine scale is possible using mass conservative interpolation methods ... [more ▼]

In this thesis we demonstrate that direct measurement and comparison across subjects of the surface area of the cerebral cortex at a fine scale is possible using mass conservative interpolation methods. We present a framework for analyses of the cortical surface area, as well as for any other measurement distributed across the cortex that is areal by nature, including cortical gray matter volume. The method consists of the construction of a mesh representation of the cortex, registration to a common coordinate system and, crucially, interpolation using a pycnophylactic method. Statistical analysis of surface area is done with power-transformed data to address lognormality, and inference is done with permutation methods, which can provide exact control of false positives, making only weak assumptions about the data. We further report on results on approximate permutation methods that are more flexible with respect to the experimental design and nuisance variables, conducting detailed simulations to identify the best method for settings that are typical for imaging scenarios. We present a generic framework for permutation inference for complex general linear models (GLMs) when the errors are exchangeable and/or have a symmetric distribution, and show that, even in the presence of nuisance effects, these permutation inferences are powerful. We also demonstrate how the inference on GLM parameters, originally intended for independent data, can be used in certain special but useful cases in which independence is violated. Finally, we show how permutation methods can be applied to combination analyses such as those that include multiple imaging modalities, multiple data acquisitions of the same modality, or simply multiple hypotheses on the same data. For this, we use synchronised permutations, allowing flexibility to integrate imaging data with different spatial resolutions, surface and/or volume-based representations of the brain, including non-imaging data. For the problem of joint inference, we propose a modification of the Non-Parametric Combination (NPC) methodology, such that instead of a two-phase algorithm and large data storage requirements, the inference can be performed in a single phase, with more reasonable computational demands. We also evaluate various combining methods and identify those that provide the best control over error rate and power across. We show that one of these, the method of Tippett, provides a link between correction for the multiplicity of tests and their combination. [less ▲]

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See detailLANDSLIDE SUSCEPTIBILITY PREDICTION IN A MOUNTAINOUS CATCHMENT: THE NARANJO BASIN, WESTERN GUATEMALA
Estrada Orozco, Nick Kenner ULg

Doctoral thesis (2017)

In tropical mountain areas, landslides triggered by heavy rainfall represent a natural hazard, especially where meteorological events such as tropical cyclones are recurrent. Rainfall-triggered landslides ... [more ▼]

In tropical mountain areas, landslides triggered by heavy rainfall represent a natural hazard, especially where meteorological events such as tropical cyclones are recurrent. Rainfall-triggered landslides may also increase in highly seismic active areas. This is the case of Guatemala, located in the Circum-Pacific Belt and between Pacific and Atlantic Oceans, sources of cyclonic events. Although Guatemala is a region where landslides are a widespread phenomenon, landslide inventories, maps and quantitative susceptibility assessments that are useful for land use planners and decision makers are hitherto non-existent. The aim of this research is to produce quantitative landslide susceptibility assessments, using logistic regression multivariate statistical method. The study area is a watershed located in the department of San Marcos (western Guatemala), impacted by a tropical storm event in October 2005. A total of 766 landslides were identified and mapped using orthoimages from 2005. Then, 99 landslides were mapped in 2011 based on field data. The main landslide type is shallow landslide (61 % in 2005), while 39 % of those landslides from 2005 evolved into debris flows. In total, susceptibility models using multivariate probabilistic approach were developed for shallow landslides, evaluating two different strategies for the sample size of non-landslides events and three different numbers of input variable in the models. Susceptibility models were developed for debris flows dataset and the union of both dataset (shallow and debris flows). The comparison of the models and the associated susceptibility maps highlighted 6 significant input variables that are associated with landslide occurences - elevation, slope, aspect, profile curvature, planform curvature and distance to roads. Performance comparisons of models were also carried out. To validate the performance of the model results, the ROC curve was used, as well as the four-fold and confusion matrix plots. A susceptibility map was generated to display the results of the models in terms of probability values. A proposal and discussion on the operational use of susceptibility maps where cutoff values can be chosen to define the lowest and highest landslide susceptibility were also made. These will help land use planners in decision-making and in implementing protective measures. [less ▲]

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See detailHistoire évolutive du complexe Afzelia Smith (Leguminosae - Caesalpinioideae) dans les écosystèmes forestiers et savanicoles en Afrique tropicale
Donkpegan, Segbedji ULg

Doctoral thesis (2017)

The genus Afzelia Smith (Fabaceae, Caesalpinioideae) is known to have seven African tree species two of which are found in the Zambezian region, one is distributed in the Sudanian region and the four ... [more ▼]

The genus Afzelia Smith (Fabaceae, Caesalpinioideae) is known to have seven African tree species two of which are found in the Zambezian region, one is distributed in the Sudanian region and the four other are endemic to the Guineo-Congolian region. These taxa, of high commercial value, are difficult to identify. They are therefore marketed under the same "doussié" name. These difficulties of distinction can prove detrimental to the sustainable management of populations. The aim of this doctoral thesis is to characterize the evolutionary history of the Afzelia genus. More specifically, this study aims to: (i) evaluate the level of morphological divergences within the Afzelia genus and describe the phylogenetic relationships in order to quantify the reproductive isolation between taxa by highlighting the role of past climate change and / or ecological gradients in the speciation of the genus; (ii) proceed to an analysis of the spatial genetic diversity and structure of Afzelia spp.; (iii) identify and describe ecological, biotic and abiotic factors that may influence population-level gene flows of an Afzelia species (A. bipindensis). A morpho-genetic analysis of Afzelia species was carried out and confirmed the strong botanical resemblance between the taxa. The savannah species are diploid and have half the size of the genome of forest species that are tetraploid. The phylogenies of genes (nuclear and chloroplastic) differ from one another and do not allow the separation of tetraploid taxa from one another. Such differences can be generated as a result of episodes of ancestral hybridization between species. These hybridizations would probably be old and would have occurred between lineages of the forest species and A quanzensis (a species of the Zambezian savannahs) lineages. Polyploidy would have occurred between 7 and 9.4 million years in the evolutionary history of the genus. In addition, Bayesian assignment and reproductive isolation analyzes suggested interspecific crosses, but only in forest species distributed sympatrically. At a more limited spatial scale, we observed two well differentiated genetic groups in sympatry in A. bipindensis. These show a morphological differentiation and a phenological shift of flowering which can contribute to their reproductive isolation. This study highlighted some important points: the discovery of a polyploid complex within the Afzelia genus, the confirmation of the delimitation of the diploid savannah species and the need to revise the delimitation of forest tetraploid species. [less ▲]

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See detailCharacterizing Thiamine Status and Mechanisms of Thiamine Supplementation on Subacute Ruminal Acidosis Attenuation in Dairy Cows
Pan, Xiaohua ULg

Doctoral thesis (2017)

Dairy cows are often fed high grain diets to maximize milk production in today’s intensive management farms. However, overfeeding high grain diets increases the risk of subacute ruminal acidosis (SARA ... [more ▼]

Dairy cows are often fed high grain diets to maximize milk production in today’s intensive management farms. However, overfeeding high grain diets increases the risk of subacute ruminal acidosis (SARA), which is characterized by prolonged decrease in rumen pH and high levels of lipopolysaccharide (LPS). SARA challenge has been confirmed to severely impair animal health, production performance and farm profitability, and more and more attentions have been paid to prevent the occurrence of SARA in dairy industry worldwide. Our teams’ previous research found that thiamine supplementation relieved SARA in dairy cows, but the modes of action of thiamine in SARA attenuation are still unclear. In this context, this thesis was conducted to increase our understanding of relationships between SARA induction and thiamine, and to explore the mechanisms of thiamine supplementation on SARA attenuation by determining its effects on rumen fermentation, microbiome composition and anti-inflammatory response. Firstly, the first experiment in Chapter III demonstrated that thiamine status in rumen and blood were altered by SARA induction and thiamine deficiency occurred during SARA challenge. Regression analysis proved the ruminal thiamine content was positively related to pH and the concentrations of acetate in the rumen, and negatively correlated to the lactate contents, indicating the altered rumen fermentation would affect thiamine status. Secondly, the mRNA expression of thiamine transporters in ruminal epithelium (Chapter IV) and ruminal bacteria compositions (Chapter V) in SARA and control cows were detected. We found that thiamine concentration was positively correlated with Bacteroides, Ruminococcus 1, Ruminobacter, Pyramidobacter and Fibrobacter, and the decrease in these genera implied SARA challenge altered ruminal thiamine status by inhibiting the growth of thiamine synthesis related bacteria. The positive correlation between ruminal and blood thiamine, and the down-regulation of thiamine transporters’ expression in rumen epithelium indicated the reduced ruminal thiamine synthesis and thiamine absorption by SARA challenge resulted in low blood thiamine content of SARA cows. Thirdly, the effects of thiamine on rumen fermentation (Chapter III), anti-inflammatory response (Chapter IV) and microbiome composition (Chapter V) were evaluated to reveal its mechanisms on SARA attenuation. We found that thiamine supplementation promoted acetate-producing bacteria including Ruminococcus 1, Pyramidobacter, Succinivibrio and Bacteroides, and decreased bacteria positively related to ruminal lactate (Succiniclasticum and Ruminococcaceae NK4A214). Consequently, rumen fermentation was improved by reducing the accumulation of lactate and increasing ruminal pH. In addition, thiamine supplementation alleviated inflammatory response in rumen epithelium by reducing the release of LPS and phosphorylation of NFκB protein, which is conducive to SARA attenuation. In summary, this thesis had increased our understanding of thiamine nutrition in dairy cows, and provided a new control strategy for subacute ruminal acidosis in dairy cows. However, further investigations are needed to deeply understand the relationship between thiamine and SARA induction, such as the isolation and validation of thiamine synthesis bacteria affected by SARA challenge, as well as to figure out metabolic pathways through which SARA induction affects thiamine synthesis in the rumen. Moreover, the impacts of overfeeding high grain diets on intestinal thiamine absorption are still unclear and need to be illuminated in dairy cows. [less ▲]

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See detailOmics insights into rumen ureolytic bacterial community and urea metabolism in dairy cows
Jin, Di ULg

Doctoral thesis (2017)

Urea has been used in the diets of ruminants as a non-protein nitrogen source. Ureolytic bacteria are key organisms in the rumen producing urease enzymes to catalyze the breakdown of urea to ammonia (NH3 ... [more ▼]

Urea has been used in the diets of ruminants as a non-protein nitrogen source. Ureolytic bacteria are key organisms in the rumen producing urease enzymes to catalyze the breakdown of urea to ammonia (NH3), and the NH3 is used as nitrogen for microbial protein synthesis. In the rumen, hydrolysis of urea to NH3 occurs at a greater rate than NH3 can be utilized by rumen bacteria, and excess ammonia absorbed into blood may be harmful to the animals. Nowadays, little is known about the information of ureolytic microorganisms in the rumen, and the changes that occur in the rumen microbial and host metabolites induced by urea nitrogen have not been fully characterized. ‘Omics’ approaches, such as metagenomics and metabolomics have been applied to analyzing rumen microbial community and nutrients metabolism in dairy cows. The objective of this study is to investigate the rumen predominant ureolytic bacteria community and the mechanisms of urea utilization in ruminants using sequencing and metabolomics approaches. Firstly, an in vitro experiment trying to explore the ruminal ureolytic bacterial community was performed. Urea or acetohydroxamic acid were supplemented into the rumen simulation systems as the stimulator and inhibitor for ureolytic bacteria, respectively. The bacterial 16S rRNA genes were analyzed by Miseq sequencing and used to reveal the ureolytic bacteria by comparing different treatments. We found that urea supplementation significantly increased the proportion of ureC genes. The rumen ureolytic bacteria were abundant in the genera of Pseudomonas, Haemophilus, Neisseria, Streptococcus, Actinomyces, Bacillus and unclassified Succinivibrionaceae. Secondly, an in vivo experiment was taken to investigate differences in ureolytic bacterial composition between the rumen digesta and rumen wall based on ureC gene classification. Six dairy cows with rumen fistula were assigned to a two-period cross-over trial. One group was fed a total mixed ration without urea and the treatment group was fed rations plus 180 g urea per cow per day. Rumen bacterial samples from rumen content and rumen wall fractions were collected for ureC gene amplification and sequencing using Miseq. More than 55% of the ureC sequences did not affiliate with any known taxonomically assigned urease genes. The wall-adherent bacteria had a distinct ureolytic bacterial profile compared to the bacteria in the rumen content. The most abundant ureC genes were affiliated with Methylococcaceae, Clostridiaceae, Paenibacillaceae, Helicobacteraceae and Methylophilaceae families. Relative abundance of the operational taxonomic units (OTUs) affiliated with Methylophilus and Marinobacter genera were significantly higher in the bacteria on the rumen wall than that in the rumen content. Thirdly, based on the in vivo experiment, rumen fluid and blood samples were collected and analyzed using nuclear magnetic resonance spectroscopy and multivariate analysis of variance. Concentrations of valine, aspartate, glutamate, and uracil in the rumen, and urea and pyroglutamate in the plasma were increased after urea supplementation. Metabolic pathways include pantothenate and CoA biosynthesis, beta-alanine metabolism, valine, leucine, and isoleucine metabolism in the rumen, and urea and glutathione metabolism in the plasma were significantly increased by urea nitrogen. In conclusion, this study identified significant populations of ureolytic bacterial community that have not been recognized or studied previously in the rumen and provides a basis for obtaining regulatory targets to moderate urea hydrolysis in the rumen. The findings also provided novel information to aid understanding of the metabolic pathways affected by urea nitrogen in dairy cows, and could potentially help to guide efforts directed at improving the efficiency of urea utilization in the rumen. [less ▲]

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See detailSoil Acidification in Southern China: Spatio-temporal Evolution and Effects on Phosphorus Availability
Zhou, Xiaoyang ULg

Doctoral thesis (2017)

Rapid industrial development and intensive agriculture induced serious soil degradation in recent decades worldwide and specifically in China. In cropland, soil acidification and nutrient deficiency are ... [more ▼]

Rapid industrial development and intensive agriculture induced serious soil degradation in recent decades worldwide and specifically in China. In cropland, soil acidification and nutrient deficiency are often associated with increased use of nitrogen (N) fertilizers. Soil acidification can lead to reduction of phosphorus (P) availability, even though with high inputs of P fertilizer. The studies presented in the thesis deal with spatio-temporal evolution of soil pH in different soil types and land uses in southern China and effects of soil acidification on soil P availability. Evolution of inorganic P fractions in Red Soil was characterized upon fertilization trials, as a response to long-term fertilization and soil acidity changes. The first focus of the thesis deals with spatio-temporal evolution and main factors of soil acidification in different soil types, parent materials and land uses of Southern China. Firstly, data from 20 monitoring sites under 25-year fertilization on Paddy Soil were investigated to research changes of pH. Paddy Soil pH significantly declined from 1988-1998, then stabilized from 1998-2013 with conventional fertilization. Chemical N fertilization, manure application, soil available N and total N increases were significantly correlated with soil pH. Secondly, changes of pH in Red Soil and Paddy Soil were assessed in 32 monitoring sites of Hunan Province (Southern China) under 10-year fertilization in order to analyze soil acidification in different soil types and agro-systems. Soil pH decline was observed in Paddy Soils under rice-vegetable rotation but not observed in Paddy Soil under continuous cropping with rice. Soil pH significantly declined in Red Soil with high initial soil pH. Thirdly, spatio-temporal characteristics of soil pH were investigated by comparison of soil pH between 1982 and 2014 in Qiyang County (Hunan Province). Average topsoil pH declined of 0.58 units between the two surveys. Soil pH in the south was lower than in the north both in 1982 and 2014. Land use and parent materials are the main drivers of differences in the soil pH changes in Qiyang County. Soil pH declined significantly in forest and upland crop over non-alkaline parent materials during 1982-2014 period. Chemical N fertilizer application can have generated 12-42 kmol H+ ha-1yr-1, which is much higher than removal by crop harvest. Reduction of chemical N fertilization and return of straws to field should be conducted to reduce H+ production and supplement base cations in Qiyang County. The second approach studied evolution of inorganic P fractions in Red Soil under 25-year fertilization, and available P and inorganic P fractions responses to various soil acidity levels. Inorganic P fractions increased under P fertilization from 1990-2015, especially Ca2-P, Ca8-P and Al-P, but inorganic P fractions significantly decreased without P fertilization. Contributions of soil properties (SOC, C:P ratio and N:P ratio) and cumulative P apparent balance (CPAB) to inorganic P fractions were ≥ 95%, while interaction of CPAB and soil properties made greater contributions than did any single factor. Soil dissolved inorganic P (DIP) decreased with rising pH value, and a minimum DIP was observed between pH 5.5 and 6.5. Olsen-P, Ca-P and Al-P increased significantly with pH between 3.4 and 5.0. Soil with pH <5.0 P availability was much lower than soil with pH ≥5.0. Managing soil acidity is a key issue regarding availability of P in Red Soil of China and our results suggest that at least a pH of 5.0 should be targeted. [less ▲]

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See detailCaractérisation des argiles utilisées dans le secteur de la terre cuite de la région de Marrakech en vue d'améliorer la qualité des produits
El Boudour El Idrissi, Hicham ULg

Doctoral thesis (2017)

The purpose of this study is to characterize the clay raw materials being exploited and used in the earthenware sector (pottery and building materials) of Marrakech region. It aims to improve product ... [more ▼]

The purpose of this study is to characterize the clay raw materials being exploited and used in the earthenware sector (pottery and building materials) of Marrakech region. It aims to improve product quality in 12 sites within a radius of 10 to 80 km around the city of Marrakech, where are active more than 850 potters spread over about 550 workshops. This characterization also aims at establishing a database on the properties of the raw materials of Marrakech and on the characteristics of the products. This will help in the selection of the most suitable materials, which generate the least defects, in restoring the historical sites of the city and in linking archaeological ceramics with their possible source of clayey material. A total of 34 samples of clay raw materials were collected from the various studied sites. 26 ceramic pastes were formed from these raw materials. Ceramic pastes have been characterized for their particle size (semi-wet sieving and laser particles size), chemical (XRF) and mineralogical compositions (XRD), plasticities (Atterberg limits), carbonate content (Bernard's calcimetry), drying behaviour (Bigot curve) and loss on ignition. The fired products were characterized by firing shrinkage, water porosity, compressive and flexural strengths and by SEM combined with EDX. The studied ceramic pastes show a large particle size variation: clay (18-66%), silt (12-53%) and sand (5-65%). Mineralogically, they are composed mainly of clay minerals (25-60%), quartz (20-55%), feldspars (5-35%), carbonates (≤15%), diopside (5-10%) and hematite (1-3%). Clay minerals are formed by illite (10-40%), kaolinite (5-15%), interstratified (≤10%), talc and pyrophyllite (≤10%), vermiculite (5%) and chlorite (≤5%). The chemical composition shows that the majority of the pastes are composed of SiO2 (48-74%), Al2O3 (12-20%), Fe2O3 (3-8%), CaO (0.4-8%), K2O (2-5%), MgO (0.5-3.5%), Na2O (0.1-2%), TiO2 (0.8-1.2%), P2O5 (≤ 0.4%) and MnO (≤ 3%). Plasticity varies from one paste to another with plasticity indices between 15 and 32. The shrinkage on drying is between 4 and 10%. For a firing temperature of 1050°C, the firing shrinkage of the various pastes is between 0.5 and 5%. The mineral transformations during firing are very diversified from one sample to another and from one site to another. The comparison of the obtained results shows that granulometry, mineralogy and degree of diagenesis are the main factors controlling plasticity. We showed a relationship between the properties of the pastes (particle size, mineralogy and plasticity) and the type of product. We proposed solutions for each of the many observed defects (poor quality of raw material, lime blowing, lime efflorescence, inadequate drying procedure, cracking, blisters, black hearts, crazing and poor ovens quality). In addition, this study valuated the clay raw materials of the Marrakech region for the use in the field of production of building materials. [less ▲]

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See detailPlant traits variability within and among populations in the context of calcareous grassland restoration
Harzé, Mélanie ULg

Doctoral thesis (2017)

In Western Europe, abandonment of traditional forms of agriculture has caused the fragmentation of semi-natural grasslands, affecting ecosystems functioning as well as population survival. Habitat ... [more ▼]

In Western Europe, abandonment of traditional forms of agriculture has caused the fragmentation of semi-natural grasslands, affecting ecosystems functioning as well as population survival. Habitat restoration has become a crucial aspect of grasslands conservation, and one of the main issues is evaluating restoration success and setting appropriate criteria to do so. Indicators used to judge whether a restoration has been successful may concern a wide range of organisms. They may be defined at different geographical scales and may concern various levels of biodiversity organization. Among them, population parameters are less represented despite their usefulness. To consider restoration as a success, restored populations of targeted species should demonstrably possess characteristics allowing their dispersal, reproduction, growth and adaptation to the environment. In this thesis, the use of plant population parameters for evaluating grassland restoration was assessed based on a literature review. Then, the success of calcareous grassland restoration was determined regarding colonization of restored grasslands by five calcareous grasslands species; Helianthemum nummularium, Hippocrepis comosa, Potentilla tabernaemontani, Sanguisorba minor and Scabiosa columbaria. Population establishment and intra-specific functional trait variability in response to the environment were observed and compared among restored and reference populations of those species, through field inventories and in-situ traits measurements in calcareous grasslands of south Belgium. Moreover, a glasshouse experiment was set-up with the aim to evaluate the intra-specific variability in response to drought stress in reference populations of P. tabernaemontani. The results indicated that population parameters were less well studied for evaluating grassland restoration success compared to indicators related to ecosystems and communities. The population parameters used to assess the success of calcareous grassland restoration showed that the study species colonized restored sites and established new populations. The fitness of the restored populations was very high. High intra-specific trait variability was highlighted at a very local scale in the reference habitat. Individuals exhibited high leaf dry matter content (LDMC), low specific leaf area (SLA) and low vegetative height in relation to low soil depth and high potential incident radiation (PDIR). These environmental variables are possibly linked to the availability of soil moisture. Further, the relationship between traits and environmental variables was not always consistent in restored sites. However, the intra-specific variability of plant traits was similar in the reference and restored grasslands. Finally, the findings from the glasshouse experiment suggested that individuals originating from drier parts of calcareous grasslands better survive drought stress.   The overall conclusion of this thesis is rather optimistic concerning restored populations of the five specialist plant species studied, specifically regarding their colonization, persistence and response to the environment or to potential climate change. The conclusions must, however, be modified depending on the reference ecosystem used as a model. This approach has to be integrated into a multi-scales and a multi-species approach to fully evaluate restoration outputs. Yet, this thesis has contributed to the understanding of population responsiveness to habitat restoration, as well as to the evaluation of restoration success of calcareous grasslands in Belgium. [less ▲]

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See detailQUALITY IMPROVEMENT OF POTATO STEAMED BREAD USING FOOD HYDROCOLLOIDS
Liu, Xingli ULg

Doctoral thesis (2017)

Nowadays, there is an increasing interest for composite or gluten-free products due to some economic, nutritional reasons or the number of the celiac patient. The estimated prevalence of Celiac disease is ... [more ▼]

Nowadays, there is an increasing interest for composite or gluten-free products due to some economic, nutritional reasons or the number of the celiac patient. The estimated prevalence of Celiac disease is about 1% of the general population, and it affects persons of any age, race, and ethnic group. Steamed bread is a traditional staple food of China, and has been consumed for at least 2000 years, taking up almost 40% of wheat consumption, and the popularity is increasing around the world. However, most traditional wheat steamed bread lack essential nutrients, including lysine, dietary fiber, vitamins, and minerals, etc. Therefore, the use of composite flour for steamed bread making has attracted great attention. Potato (Solanum tuberosum) is one of the most widely planted vegetables worldwide and is the only tuber used as a major food crop. Potato has a balanced amino acid composition, high total vitamin and mineral levels, and also contains phytochemicals such as polyphenols, polyamines, and carotenoids. However, the replacement of wheat flour is a major challenge for food technologist to produce the steamed bread with desirable quality and technological properties because that gluten is important to retain gas to obtain the desired volume and texture in a dough system. It is essential to form a strong protein network required for the desired viscoelasticity, and the easiest way to ensure the viscoelasticity properties is via the use of food hydrocolloids. Therefore, the aim of this work was to study the quality improvement of potato steamed bread using food hydrocolloids. Firstly, the influence of potato flour on dough rheological properties and quality of steamed bread showed that the dough stability and specific volume of steamed bread were significantly decreased with the potato flour proportions increasing. Then we carried out the comparative study of the nutritional quality of steamed and baked breads from four potato cultivars because that the steamed and baked breads were two type of staple food in eastern and western countries, respectively. The results showed that potato flour addition increased the contents of dietary fiber, potassium, vitamin C, and total polyphenol contents and antioxidant activity. Hongmei was the optimum choose of the studied four cultivars, followed by Blue Congo, Shepody, and Atlantic, in terms of nutritional value. For the same cultivar, the nutritional value of steamed bread was higher than that of baked bread. Secondly, the effect of different food hydrocolloids on the dough rheology and steamed bread quality parameters in composite and gluten-free formulations based on potato flour was studied. Compared to control, the food hydrocolloids addition significantly increased tightly bound water population, water absorption, starch gelatinization temperature, dough viscoelasticity, recovery percentage and development height. Little adhesion and aggregation of starch were observed and the density of potato protein bands was decreased when food hydrocolloids were added, suggesting that some aggregation formed between starch-hydrocolloids or proteins-hydrocolloids. Moreover, steamed breads with food hydrocolloids presented higher specific volume, lower hardness, and lower estimated glycemic index. In conclusion, food hydrocolloids showed the potential as a gluten replacement in composite or gluten-free potato steamed bread, particularly HPMC. Thirdly, we optimized the formulations of gluten-free potato steamed bread. The optimal gluten-free steamed bread could be produced by adding 4.84 g/100g pregelatinized potato flour (PGPF), 1.68 g/100g hydroxypropylmethylcellulose (HPMC), 5.87 g/100g egg white protein (EWP) and 69.69 g/100g water based on potato flour, and this optimal bread was compatible with regular wheat bread in key sensory properties. Moreover, the optimized solid phase microextraction parameters (sample weight 2.42 g, extraction time 60 min, and extraction temperature 50°C) were adopted to determine the volatile compounds of gluten-free potato steamed bread. 72 volatile compounds were detected in the dough and crumb. The contents of alcohols, acids and esters increased significantly with the fermentation time increasing, which would improve the aroma of steamed bread. However, further investigations are needed to elucidate the underlying mechanisms of action and the interactions with dough components and making additives. The other studies should be focused on technological approaches to improve steamed bread quality, which involved different flour particles, high pressure technology and application of sourdough. [less ▲]

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See detailThe behavior of pesticide during beer brewing and the toxicity of pesticide using state-of-the-art omic tools
Kong, Zhiqiang ULg

Doctoral thesis (2017)

Beer is an extremely popular beverage worldwide, representing the third-most popular drink after water and tea. And barley is the major raw material used for beer production. However, various combinations ... [more ▼]

Beer is an extremely popular beverage worldwide, representing the third-most popular drink after water and tea. And barley is the major raw material used for beer production. However, various combinations of pesticides are widely used at several stages of barley culti¬vation and during post-harvest storage to control pest and fungal disease. Hence, traces of these pesticides might remain in the beer produced from the treated ingredients. Hence, monitoring trace levels of pesticide residues during beer brewing and investigated the effects of pesticide residue on the quality of beer is essential. First, the behavior and fate of 3 pesticides (triadimefon, malathion, and dichlorvos) and the main metabolites (triadimenol and malaoxon) during barley storage or beer processing were assessed using a pilot-plant equipment. The residues of all products were determined using liquid chromatography coupled with tandem mass spectrometry. Field investigation of the dissipation rate kinetics for triadimefon and malathion during storage indicated that their half-life was twice as high when 5 times the recommended dosage was used. Milling had little effect on removing dichlorvos and malathion residues, whereas they were substantially removed when the spent grains were mashed. The calculated processing factors after processing were all <1, indicating that the residual ratios of dichlorvos and malathion were reduced during the entire process. In conclusion, storage and processing extensively reduced pesticide residue levels in barley and beer; however, greater focus needs to be paid to the toxicity of their metabolites in commercial by-products. Then we selected the triadimefon as the target fungicide to further study its behavior, the dissipation kinetics of TF during fermentation mediated by two different yeast strains, Saccharomyces cerevisiae IAPPST 1401 (Y1) and CICC 1202 (Y2), and found that Y2 promoted the degradation of TF. Response surface methodology was used to optimize fermentation process variables, in order to achieve the maximum removal rate of TF and the minimum production of its corresponding metabolite, triadimenol (TN). Triadimefon is also a widely used triazole fungicide with one chiral carbon center, Stereoselective degradation of triadimefon was found during barley storage, the half-life of S-(+)-triadimefon was 36.5d, 31.5d and 30.1d, while R-(-)-traidmefon was 69.3d, 53.3d and 33d under 4°C, 25°C and 40°C, respectively. During brewing process, both enantiomers of triadimefon were easily degraded. After fermentation, little triadimefon detected in the beer, while RS-(+) and SS-(-)-triadimenol were detectable. This research provides accurate information for evaluating the risk of food safety. Furthermore, we investigated the effect of triadimefon affect the quality and flavor of the fermented beer, The effect of triadimefon on yeast growth and the sensory quality of beer were studied. There were significant differences in sensory quality between beer samples fermented with and without triadimefon based on data obtained with an electronic tongue and nose. Such an effect was most likely underlain by changes in yeast fermentation activity, including decreased utilization of maltotriose and most amino acids, reduced production of isobutyl and isoamyl alcohols, and increased ethyl acetate content in the fungicide treated samples. Furthermore, yeast metabolic profiling by phenotype microarray and UPLC/TOF-MS showed that triadimefon caused significant changes in the metabolism of glutathione, phenylalanine and sphingolipids, and in sterol biosynthesis. Thus, triadimefon negatively affects beer sensory qualities by influencing the metabolic activity of S. cerevisiae during fermentation, emphasizing the necessity of stricter control over fungicide residues in brewing by the food industry. [less ▲]

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See detailRôle des lymphocytes T TCR γδ dans la progression des lésions associées à l'infection par les papillomavirus humains
Van Hede, Dorien ULg

Doctoral thesis (2017)

Cervical cancer was the fourth most frequent cancer in women in 2012, with the majority of cases occurring in less developed countries. Although this cancer is induced by Human Papillomavirus (HPV ... [more ▼]

Cervical cancer was the fourth most frequent cancer in women in 2012, with the majority of cases occurring in less developed countries. Although this cancer is induced by Human Papillomavirus (HPV) infections that have a high prevalence, only a very few percentage of infected women will developed this disease. Host immune defenses are essential to clear infection and to kill virus-infected transformed cells. Indeed, majority of infected women clear the virus within two years while immunocompromised patients are more likely to develop cervical preneoplastic lesions and cancers. γδ T cells have been shown to protect against the formation of squamous cell carcinoma (SCC) in several models. Nowadays, the contribution of γδ T cells in HPV associated uterine cervical SCC is unknown. Here we investigated the impact of γδ T cells in a transgenic mouse model of carcinogenesis induced by HPV16-oncoproteins. Surprisingly, γδ T cells promoted the development of HPV16-oncoprotein-induced lesions. These oncoproteins induced a decrease in epidermal Skint-1 expression and modification of the associated anti-tumor Vγ5+ γδ T cells (or DETC), which were joined by other γδ T cell subsets actively producing IL-17. Consistent with a proangiogenic role, γδ T cells promoted the formation of blood vessels in the dermis underlying the HPV-induced lesions. In human cervical, IL-17+ γδ T cells could be only observed at the cancer stage (SCC) (but not in less advanced cervical lesions), where HPV oncoproteins are highly expressed, supporting the clinical relevance of our observations in mice. Overall, our results suggest that HPV16-oncoproteins induce a reorganization of the local epithelial-associated γδ T cell Subpopulations thereby promoting angiogenesis and cancer development. [less ▲]

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See detailSpatial diversification of agroecosystems towards biological control of insect pests: A focus on intercropping and wildflower strips
Hatt, Séverin ULg

Doctoral thesis (2017)

Facing the limits of input-intensive agriculture, agroecology aims at thinking ways to design a sustainable agriculture that is economically viable and socially relevant. It notably invites to mobilize ... [more ▼]

Facing the limits of input-intensive agriculture, agroecology aims at thinking ways to design a sustainable agriculture that is economically viable and socially relevant. It notably invites to mobilize ecological processes within agroecosystems in order to enhance the delivery of ecosystem services towards reducing the use of external inputs – among others insecticides. For enhancing biological control of insect pests, a strategy is to spatially diversify agroecosystems at the field scale. Whereas increasing plant diversity could directly negatively affect pest development on the one hand (i.e. bottom-up effect), providing flowering features could allow the enhancement of natural enemies and their direct effect on pest populations on the other hand (i.e. top-down effect). The present thesis focused on intercropping (i.e. the cultivation of at least two crop species simultaneously in a same field) as a way to diversify crop habitat, and the sowing of wildflower strips as a non-crop feature. A systematic analysis of the literature revealed that, in most of studies, wheat (Triticum aestivum L.)-based intercropping allows a reduction of insect pests on crops, without necessarily favouring their natural enemies, compared to pure-stands. Besides, the provision of flowering resources, by for instance sowing wildflower strips, can attract and support flower visiting predators and parasitoids. Hence, in a first set of field experiments, combining the two tactics of increasing crop diversity and providing flowering resources was tested. First in China, wheat crop was associated with oilseed rape (Brassica napus L.), but it neither allowed reducing aphid (Hemiptera: Aphididae) abundance nor enhancing their natural enemies compared to pure stands. Instead, aphid density – independently from the treatments – affected natural enemy abundance, and interspecific relations between aphids and their natural enemies were observed. Second in Belgium, wildflower strips were sown within a wheat field, which led to a reduction of aphid density in wheat plots in between flowering features and an increase of aphidophagous hoverflies (Diptera: Syrphidae) compared to pure-stand wheat. Nevertheless, the presence of flowering strips did not affect the other natural enemies, i.e. lacewings (Neuroptera: Chrysopidae), ladybeetles (Coleoptera: Coccinellidae) and parasitoid wasps (Hymenoptera: Braconidae). Therefore, a second set of field experiments focussed on ways to compose mixtures of wild flowers attractive to a diversity of natural enemies. Flower functional traits were considered due to their effect on insect behaviour. First, the hypothesis that mixtures with high functional diversity attract and support a high abundance and diversity of aphid flower visiting predators was tested. This hypothesis was not verified. Instead, the high density in the plots of some flower species (especially the Asteraceae Leucanthemum vulgare Lam.) known to be attractive to flower visitors was supposed to have overwhelmed the effect of functional diversity. Second, a methodology was developed to identify which flower traits significantly affect natural enemy abundance – in this experiment parasitoids of oilseed rape beetle pests (i.e. Meligethes spp. [Coleoptera: Nitidulidae] and Ceutorhynchus spp. [Coleoptera: Curculionidae]) – in flower mixtures. Among seven traits, visual traits (i.e. colour, ultra-violet reflectance) and the one related to food availability (i.e. corolla morphology) were found to significantly affect parasitoid abundance. These results highlight that (i) increasing plant diversity at the field scale can – but not systematically – favour a reduction of insect pests, (ii) including flowering features can enhance some – but not all – of their natural enemies, and (iii) in order to compose flower mixes attractive to natural enemies, specific flower traits – rather than functional diversity at the mixture level – can be considered. These results are discussed in a broader perspective. Indeed, strategies to spatially diversify crop and non-crop habitats in agroecosystems are various, as well as the ways to compose, manage and design such habitats. Also, processes at larger scales than the field may be determinant. Moreover, insects are not the only pests, and pests are not the only biotic or abiotic elements that need to be regulated in agroecosystems. Controlling multiple pests simultaneously but also enhancing the provision of multiple regulating services represent challenges for future research in agriculture. [less ▲]

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See detailCrop water productivity of winter wheat at multi-scale and its improvements over the Huang-Huai-Hai Plain, China
Liu, Qin ULg

Doctoral thesis (2017)

Droughts and water shortage are generally accepted to be one of the most critical problems faced by worldwide agriculture, and it is so especially in China where agricultural production and prosperity are ... [more ▼]

Droughts and water shortage are generally accepted to be one of the most critical problems faced by worldwide agriculture, and it is so especially in China where agricultural production and prosperity are largely dependent on the timely, adequate and proper distribution of rainfall. The analysis of water productivity is becoming very critical in light of population growth, food security and increasing pressure on water resources. However, there is limited understanding of the spatio-temporal variation of crop water productivity (CWP) from the rotation system and its key influencing factors in Huang-Huai-Hai Plain (3H Plain) in which there is an over-exploitation of groundwater region and where future warmer and drought conditions will intensify crop water demand. As the largest water user, agricultural sector is facing a challenge to produce more crops with less water. Consequently, 3H Plain faced the double threat of both making contributions of high and stable yield to government and improving CWP of winter wheat through reducing water consumption. The overall ambition of this thesis was to investigate to what extent the grain yield and crop water productivity for winter wheat can respond to climate change and drought across the 3H Plain. In our study, a combined dataset composed of a historical 54-year time series and the RCP 8.5 scenario from 40 meteorological stations was provided by the China Meteorological Administration. Among these 40 stations we selected 12 stations with more detailed information available. The minimal data sets required for model operation include daily climatic variables, soil information and management information collected from the China Soil Scientific Database. Finally, we also used satellite data to estimate water productivity mainly involved in MODIS products including MOD11A1 (land surface temperature/surface emissivity), MOD13A2 (NDVI) and MCD43B3 (surface albedo). We used SPEI-PM method, DSSAT-CERES-Wheat model and SEBAL model to explore the characteristics in grain yield and crop water productivity for winter wheat in response to climate change and drought associated with their improvements across the 3H Plain. Our work demonstrated the investigation that an increase of ET0 was predicted leading to subsequent drought rise in frequency, duration, severity and intensity under the RCP 8.5 scenario. The cumulative probability of the simulated yield reduction was detected to be higher during jointing to heading stage in northern than southern region due to water stress and changes in the management inputs. The lower CWP was mainly situated in the low plain-hydropenia irrigable land and dry land (zone2) and the hill-wet hot paddy field (zone6), which suggests that it is an important issue and opportunity for improving agricultural water management in the water-scarce 3H Plain. The spatial increase of yield principally controlled increase of water productivity in north agricultural sub-regions and the spatial increase of water productivity was more governed by increment of yield than the reduction of ETa in other agricultural sub-regions. It will be adopted to develop feasible straw mulching, regulated deficit irrigation, and soil water storage and preservation to reduce pressure on groundwater over-exploitation, especially for winter wheat in the 3H Plain. In our work, major agronomic consequences have been drawn regarding the reform of the common agricultural policy in Huang-Huai-Hai Plain, China. Researchers are encouraged to further investigations into how to implement these practices with emphasis of improving the sustainability of these agro-ecosystems. [less ▲]

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See detailGENETIC DIVERSITY AND FACULTATIVE SYMBIONTS INFECTION PATTERNS OF TWO RHOPALOSIPHUM APHIDS
Guo, Jianqing ULg

Doctoral thesis (2017)

Aphids, during the long-term evolution, kept their genetic traits for continuation of the species while some variations caused by selection, migration, mutation, and genetic drift occurred meanwhile to ... [more ▼]

Aphids, during the long-term evolution, kept their genetic traits for continuation of the species while some variations caused by selection, migration, mutation, and genetic drift occurred meanwhile to adapt to novel environments. The differentiation takes place not only among species but could also be observed within species that finally contributes to the population genetic diversity. However, the migrant behavior of aphid can enhances the gene flow among populations, as a result, decreasing the genetic variation. Additionally, insect such as aphids usually hold the mutualistic relationships with endosymbionts which may affect the adaptive characteristics of the host aphid. Both Corn leaf aphid Rhopalosiphum maidis (F.) (Hemiptera: Aphididae) and Bird cherry-oat aphid Rhopalosiphum padi (L.) (Hemiptera: Aphididae) are worldwidely severe pests that attack cereal crops such as maize, barley, wheat, sorghum and oats. They suck the phloem and can transmit viruses including Maize dwarf mosaic virus (MDMV) and Barley yellow dwarf virus (BYDV), the main virus of maize and barley, which may result in serious damage for the yield and quality of the host plant. Moreover, one aphid species usually exerts genetic differentiation among populations which is related to factors such as geographic conditions, host plants and life history. Hence, it is necessary to have a clear understanding of the genetic structure and variation among geographic populations to further explore the historical expanding routes and occurrence of these pests and design efficient control strategies. Targeting the genetic divergence among populations of two Rhopalosiphum aphids, 32 populations of R. padi and 38 populations of R. maidis were collected on maize from most regions of China as well as some countries in Europe. The sequencing results of two mitochondrial (COI and COII) and one nuclear (EF-1α) genes indicated that a high level of gene flow existed among the populations of R. maidis in terms of geographic locations, proving the migratory capacity of this aphid. With regard to R. padi, high genetic diversity were found between the populations from China and Europe based on combined COI-COII, however, the genetic diversification among Chinese populations and European populations were low, which illustrated that the length of geographic distance may play an important role in genetic diversity. The infection patterns of seven facultative symbionts (Serratia symbiotica, Hamiltonella defensa, Regiella insecticola, Rickettsia, Spiroplasma, Wolbachia and Arsenophonus) in R. padi and R. maidis were investigated as well. Both aphids were found to have wide symbiotic associations with variant symbionts. Unlike Acyrthosiphum pisim (H.) which is frequently infected with S. symbiotica, R. insecticola, Rickettsia and Spiroplasma were dominant facultative symbionts in these two Rhopalosiphum aphids. The results also indicated that the geographic conditions such as latitude of collecting locations may have an effect on the distribution of facultative symbionts, implying the adaptive function of the facultative symbionts to various environmental conditions on their host aphids. Considering the population diversity within species, we also tested the survival and reproduction rates of two R. maidis populations (i.e. Beijing and Mangshi) on barley and maize of small (10 cm) and high (50 cm) size. Direct observation method was used and none of the populations could survive on maize of small size whereas they were capable to develop on maize of high size, but with much lower growing speeds compared with barley on which both populations showed the best performances. In addition, Beijing population was found to perform significantly better than Mangshi population which may be related to the infection of facultative symbionts. We hypothesize that the lethality on small maize may result from the secondary metabolites synthesized to be more abundant in young maize seedlings. [less ▲]

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See detailDevelopment and applications of CRISPR-Cas9 and RNAi for rice and wheat agronomic traits improvement
Sun, Yongwei ULg

Doctoral thesis (2017)

Genome editing technologies enable precise modifications of DNA sequences in vivo and offer a great promise for harnessing plant genes in crop improvement. The precise manipulation of plant genomes relies ... [more ▼]

Genome editing technologies enable precise modifications of DNA sequences in vivo and offer a great promise for harnessing plant genes in crop improvement. The precise manipulation of plant genomes relies on the induction of DNA double-strand breaks (DSBs) by sequence-specific nucleases (SSNs) to initiate DNA repair reactions that are based on either non-homologous end joining (NHEJ) or homology-directed repair (HDR). NHEJ can result in frame-shift mutations that often create genetic knockouts. These knockout lines are useful for functional and reverse genetic studies but also have applications in agriculture. HDR has a variety of applications as it can be used for gene replacement, gene stacking, and for creating various fusion proteins. An overview of development and applications of precise GT in plants using SSNs systems is presented in Chapter I. Cereals high in amylose content (AC) and resistant starch (RS) offer potential health benefits. Starch branching enzyme (SBE) plays a major role in determining the fine structure and physical properties of starch. Here, we use CRISPR/Cas9 technology to generate targeted mutagenesis in SBEI and SBEIIb in rice. The frequencies of obtained homozygous or bi-allelic mutant lines with indels in SBEI and SBEIIb in T0 generation were from 26.7 to 40%. SbeII mutants showed higher proportion of long chains presented in debranched amylopectin, significantly increased AC and RS content to as higher as 25.0% and 9.8%, respectively. The details of results are presented in Chapter IV Complete knockouts and loss-of-function mutations are very valuable in defining gene functions, their applications in crop improvement are somewhat limited because many agriculturally important traits are conferred by point mutations or a change of gene expression levels. Development of a technology that enables gene replacement rather than gene inactivation will greatly facilitate plant breading. In this study, we report an efficient method to introduce multiple discrete point mutations in the rice ALS gene using CRISPR/Cas9-mediated homologous recombination. We not only generated homozygous herbicide resistance rice plants in one generation, but also demonstrated that the presented strategy is feasible and effective in precise gene replacement by using CRISPR/Cas9 system to facilitate crop genetic improvement. The details of results are presented in Chapter V Aphids are major agricultural pests which cause significant yield losses of wheat each year in China. Present attempts to improve the aphid resistance of wheat through conventional breeding in China are being confronted by slow progress due to lack of aphid resistant wheat germplasm, the complexity of plant-aphid interactions and the rapid development of resistant pest biotypes. An overview of the engineering of plants for aphid resistance is presented in chapter II. We identify a gene (23028) related to aphid ingestion and digestion from the aphid, S. avenae. Aphids fed on plant material expressing double-stranded RNA (dsRNA) specific to 23028 and C002 show a decline in growth, reproduction and survival rates. The details of results presented in the chapter VI. [less ▲]

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See detailStrategies of host defense and viral counter defense: analysis of Fusarium graminearium responses to FgHV1 infection
Wang, Shuangchao ULg

Doctoral thesis (2017)

Viruses that selectively infect fungi are named fungal viruses or mycoviruses. Fungal viruses exist in all major groups of fungi and are important in both fundamental research and biological control of ... [more ▼]

Viruses that selectively infect fungi are named fungal viruses or mycoviruses. Fungal viruses exist in all major groups of fungi and are important in both fundamental research and biological control of plant pathogens. Fusarium graminearum hypovirus 1 (FgHV1) was the first virus isolated from F. graminearum belonging to the hypoviridae family. FgHV1 was supposed to encode two open reading frames, which had high sequence identities with Cryphonectria hypovirus 1 and 2 (CHV1 and CHV2). F. graminearum strain infected with FgHV1 showed lower growth rate and reduced conidia production, but with no pathogenicity change. To elucidate the host defense and viral counter defense mechanism, we analyzed the F. graminearum stress responses to FgHV1 infection from several aspects. In the first part, we preliminarily elucidated the RNA silencing mechanism of the F. graminearum/hypovirus system from a small RNA (sRNA) perspective. The length distributions of F. graminearum sRNA were altered by FgHV1 infection, especially 24-nt sRNA. Extensive FgHV1-derived sRNAs were detected, yielding the first high resolution map of sRNA from mycoviruses. In particular, the RNA silencing-related genes FgDicer1 and FgRdRp5 were predicted targets of FgHV1- and FgHV2-derived siRNAs, possibly revealing a novel anti-RNA silencing strategy employed by mycoviruses. In the second part, we performed genome-wide expression analysis to reveal stress-related genes with expression changes in response to FgHV1 infection. A total of 248 differentially expressed genes were identified. Cellular redox regulation related genes were the most affected categories in F. graminearum challenged with FgHV1. Then we verified that FgHV1 encoded protein 20 (p20) could induce the H2O2 accumulation and hypersensitive response in Nicotiana benthamiana leaves. In the last part, our experiments confirmed that p20 functioned as a RNA silencing suppressor (RSS) with the agroinfiltration-mediated technique, making p20 the third RSS identified in mycoviruses. By incorporating single strand sRNA, p20 could suppress host RNA silencing. Globally, the defense responses of F. graminearum to FgHV1 infection were studied all-around and in-depth. On the other hand, FgHV1 developed counter defense strategies to protect from invasion resistance. [less ▲]

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See detailImprovement of the ChIP-seq technique for histone posttranslational modifications through enhanced laboratory protocols and data processing methods
Laczik, Miklos ULg

Doctoral thesis (2017)

Massively parallel sequencing has rapidly become the dominant technique in various omics studies as it provides an unequalled amount of high quality quantitative data for a reasonable cost that is ... [more ▼]

Massively parallel sequencing has rapidly become the dominant technique in various omics studies as it provides an unequalled amount of high quality quantitative data for a reasonable cost that is decreasing ever since the first next generation sequencers appeared. Subsequently, chromatin immunoprecipitation coupled with massively parallel sequencing (ChIP-seq) is the prevailing method of choice for investigating protein–DNA interactions in a genome-wide manner. Bioinformatics tools are also evolving quickly to meet the increasing demands of processing huge amounts of ChIP-seq data and to open the way for novel techniques and insights. However areas still exist that could benefit from improved wet-lab and dry-lab methods. One such area is data visualisation and interpretation; another is the ChIP-seq study of histone posttranslational modifications, especially the research of inactive histone marks which tend to produce diffuse broad enrichments instead of point-source peaks. Achieving proper enrichment and unbiased analysis in such histone mark studies proves to be a great challenge. In this doctoral thesis we show how we addressed these issues on both the level of bioinformatics and the level of sample processing methods. We present our innovative analysis tools we developed to this end, among others a highly customisable, feature rich viewer for next generation sequencing data visualisation, and an analysis pipeline specifically aimed to handle broad enrichments from ChIP-seq studies of (inactive) histone marks. We propose specific software and specific peak calling settings to detect a range of histone modifications accurately, and we describe the way to determine the optimal settings. Along the pipeline we also present a protocol designed to enhance enrichments and facilitate peak detection in broad peak studies typical of inactive histone marks. We demonstrate how this method affects various enrichment types and propose potential applications that could benefit from it. Furthermore we show diverse achievements with the analysis pipeline, including the interpretation of the aforementioned wet-lab method, and the development of an automated ChIP-seq protocol optimised for low cell numbers. [less ▲]

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See detailField border flowering strips as a source of valuable compounds
Paul, Aman ULg

Doctoral thesis (2017)

Intensification of agricultural practices has caused irreversible damage to environment during the last few years. Several consumers are now deviating towards healthier diets produced from eco-friendly ... [more ▼]

Intensification of agricultural practices has caused irreversible damage to environment during the last few years. Several consumers are now deviating towards healthier diets produced from eco-friendly and sustainable agricultural systems. In this regard, the possibilities of utilizing edible biomass originating from sustainable agricultural practices have gained recent attention. The underutilized edible plants, especially their seeds could be one of the interesting alternates, as some of these seeds are not only nutritious, but could also be produced using sustainable practices. Similarly, edible insects represent another category of biomass which are rich in nutrients and could be produced sustainably. The seeds from underutilized edible plants and the edible insects could be simultaneously harvested using a sustainable agricultural system involving field border flowering strips. Field border flowering strip is a part of agricultural landscape that is reserved for herbaceous vegetation. These strips are popularly grown throughout the world to enhance biodiversity. The main objective of this thesis is to utilize seeds from some of the plants grown as field border flowering strips and insects that find refuge in these plants for the provision of food and health promoting substances. From the literature reviewed in chapter two, it was observed that: (1). Most plants that are grown in field border flowering strips are edible, and their aerial parts have been extensively analyzed for chemical composition. However, there is a scarcity of literature evaluating chemical composition/food utilization of the seeds from plants that are grown as field border flowering strips. So, the primary objective of this thesis is to investigate the nutritional and health promoting potential of the seeds from some plants that are grown in these strips. (2). A number of grasshopper species find refuge in field border flowering strips. Several grasshopper species are considered edible throughout the world and they are interesting source of nutrients. So the secondary objective of this thesis is to screen some edible grasshopper species that are present in field border flowering strips, analyze their nutritional value, and investigate possibilities to establish their commercial rearing for ensuring year-long availability of edible biomass. The research strategy adopted to achieve the objectives of this thesis is mentioned in chapter three. This chapter includes details about the selection of raw materials (both plant seeds and insects), and subsequent analysis. Chapter four contains the detail about the materials and methods used for analysis during this study. Chapter five includes details about the investigations on edible insects. Chorthippus parallelus Zetterstedt species grasshoppers were shortlisted for detailed investigation due to their high densities in field border flowering strips. This insect species was analyzed for proximate composition, amino acid profile, fatty acid profile and mineral profile. Moreover the toxicity of these insects was also evaluated using two different models. Results indicated that these insects could be consumed as an alternate source of proteins (69%) and omega-3 fatty acid rich lipids (10%). Rearing trials done during this study indicates that commercial rearing could be developed to produce sufficient and safe biomass for human consumption. The selection of seeds from three plant species (Achillea millefolium L., Anthriscus sylvestris (L). Hoffm. and Prunella vulgaris L.), for detailed analysis on the basis of lipid content and fatty acid profile has been mentioned in chapter six. Chapter seven, eight and nine include the details about the composition and anti-oxidant activity of A. millefolium, A. sylvestris and P. vulgaris seeds, respectively. Proximate composition, lipid profile, amino acid profile, mineral profile, lignocellulosic profile, phenolic profile and phytate content of the three plant seeds were investigated during this study. Two new phenolic acids were discovered originating from P. vulgaris seeds. These compounds were named amolsamic acid A and amolsamic acid B. Discovery of these compounds was the true highlight of this thesis. All the three plant seeds were found to contain substantial level of total phenolics (0.8-2.6%) and interesting phenolic profiles (dominated by chlorogenic acid, rosmarinic acids and related compounds). Keeping this in mind, the detailed anti-oxidant activity (including anti-radical scavenging, horseradish peroxidase response modulation, cellular anti-oxidant, myeloperoxidase response modulation and anti-lipid peroxidation activity) of their respective seed extracts was also analyzed. Results obtained during this study indicate that A. millefolium, A. sylvestris and P. vulgaris seeds not only contain interesting level of nutrients, but their extracts also exhibit significant anti-radical scavenging, horseradish peroxidase response modulation, cellular anti-oxidant (IC50 values order: P. vulgaris>A. sylvestris>A. millefolium) and myeloperoxidase response modulation activity (IC50 values order: A. sylvestris>A. millefolium>P. vulgaris for both direct and SIEFED assay). The main conclusions (chapter ten) of this PhD dissertation are: (1). C. parallelus insects could be viewed as an alternative source of nutrients to diversify human diets. The preliminary rearing studies done during this study indicate that commercial rearing could be developed for generation of substantial (and safe) biomass to support human consumption. (2). A. millefolium, A. sylvestris and P. vulgaris seeds could be included in food formulations (or consumed as whole) as a source of proteins, lipids, minerals and phenolics. P. vulgaris seeds could also be used for the extraction of two new phenolic constituents (amolsamic acid A and amolsamic acid B). The first investigations involving A. millefolium, A. sylvestris and P. vulgaris seeds realized during this study, indicate that seed extract (or whole seeds) from all three plants could possibly be consumed for the prevention of neutrophil and myeloperoxidase mediated damage in human body. [less ▲]

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See detailLa ligue d'Action française: mode d'organisation et pratiques culturelles, sociales et politiques (1905-1936)
Schmidt, Anne-Catherine ULg

Doctoral thesis (2017)

Notre thèse se décline en une approche chronologico-thématique autour de trois pôles majeurs. Il s'agit, tout d'abord d'une démonstration qui entend établir un tableau aussi précis que possible de la ... [more ▼]

Notre thèse se décline en une approche chronologico-thématique autour de trois pôles majeurs. Il s'agit, tout d'abord d'une démonstration qui entend établir un tableau aussi précis que possible de la structure, des rouages et de l'implantation des organisations d'AF à Paris et en province. L'objectif est ensuite d'analyser les grandes matrices de l'engagement militant mais aussi et surtout leurs évolutions successives en lien avec un contexte politico-diplomatique extrêmement mouvant. Il s'agit pour chaque période donnée de chercher à comprendre ce qui constitue l'engagement au sein de la ligue dans une approche résolument tournée vers la base militante. Enfin, il faut réfléchir à la place et au rôle de l'AF dans la nébuleuse royaliste et nationaliste de son temps afin de comprendre les jeux d'alliance et de concurrence entre les diverses organisations mais aussi dans quelle mesure et de quelle manière la ligue d'AF s'est intégrée au répertoire d'action collective de son temps tout en participant à son renouvellement. Le choix de notre découpage chronologique répond à des nécessités à la fois contextuelles et propres à l'histoire de l'Action française. Au cours de la première période, de 1905 à 1914, on assiste à une structuration rapide et continue de l'appareil d'action intellectuelle et militante. Les rouages nationaux et locaux de la ligue se mettent en place et les matrices de l'engagement militant sont diffusées par l'intermédiaire du quotidien et contribuent à influencer l'opinion publique. A cette époque, l'AF est presque seule dans le champ nationaliste mais doit se positionner au sein du monde royaliste. Pendant la Grande Guerre, les structures de la ligue sont désorganisées. L'objectif principal est alors de continuer à diffuser le journal ce qui n'empêche pas la ligue d'utiliser le temps de guerre pour tenter de nouvelles méthodes de propagande notamment dans l'armée. La période 1914-1918 permet aussi à l'AF de se respectabiliser en choisissant la voie de l'Union sacrée. Elle reste malgré tout une organisation particulièrement surveillée d'autant plus que son influence dans l'opinion publique s'accroît. Après-guerre, l'AF se réorganise partout en province. Au cours de la période 1919-1926, elle fait l'expérience de la vie parlementaire et glisse, de fait, vers une sorte de conservatisme contre lequel elle s'est initialement constituée. Ses échecs électoraux couplés à l'influence croissante des communistes dans la vie publique contribuent à relancer son activisme militant mais pas suffisamment selon certains de ses membres qui suivent alors Georges Valois dans la dissidence du Faisceau. L'AF doit également faire face à l'apparition d'une nouvelle concurrence nationaliste avec la naissance des Jeunesses Patriotes. En 1926, elle est confrontée à la plus grave crise de son histoire : sa condamnation pontificale. Au cours de la période 1927-1929, la ligue cherche à rebondir et à maintenir son implantation et ses activités dans un contexte, par ailleurs, globalement défavorable. Les résultats sont extrêmement nuancés selon les régions mais, dans l'ensemble, il n'y a pas d'écroulement de sa structure militante même si les difficultés financières de la ligue sont de plus en plus importantes. Au tournant des années 1930, la crise économique aggrave encore ces difficultés mais contribue aussi à créer un contexte favorable à un nouvel épisode de flambée ligueuse. Au cours de la période 1933-1936, l'AF connaît un regain de vitalité dont le paroxysme se situe au moment du 6 février 1934. Cela étant, cet épisode démontre également les limites et les faiblesses du phénomène ligueur nationaliste en France. [less ▲]

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See detailModulation strategies of integrated HVAC systems used in residential buildings for demand-side management at different scales
Georges, Emeline ULg

Doctoral thesis (2017)

The integration of renewable energy sources in the electricity production mix has an important impact on the management of the electricity grid, due to their intermittency. In particular, to ensure grid ... [more ▼]

The integration of renewable energy sources in the electricity production mix has an important impact on the management of the electricity grid, due to their intermittency. In particular, to ensure grid balancing, there is a rising need for flexibility, both on the supply and demand sides. A possible solution to help achieve grid balancing is the smart modulation of the electrical load in a "demand following supply" scheme through demand-side management. In this context, the objective of this doctoral thesis is to assess the amount of flexibility that can be harvested from the management of residential thermostatically-controlled loads and, in particular, through the use of heat pumps and storage. To that end, a modeling and control framework is developed to define efficient and scalable optimal load modulation strategies. The flexibility potential is investigated in different contexts: day-ahead electricity market, matching of decentralized electricity production and provision of ancillary services. Different scales are considered, from a single building to several thousand buildings. [less ▲]

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See detailAlle origini della conservazione in Belgio: il contributo originale di Louis Van der Swaelmen
Rapalo, Maria Chiara ULg

Doctoral thesis (2017)

La recherche proposée s’intègre dans le cadre d'une collaboration entre l'Italie et la Belgique portant sur les questions de la conservation et de la protection du paysage, lies au thème de l'urbanisme ... [more ▼]

La recherche proposée s’intègre dans le cadre d'une collaboration entre l'Italie et la Belgique portant sur les questions de la conservation et de la protection du paysage, lies au thème de l'urbanisme. L’objectif de cette collaboration est de mettre en évidence les contributions d’échelles diverses qui, dans le contexte belge, ont contribué à l'émergence des directives internationales actuelles dans le domaine de la conservation et de la protection des centres historiques et du paysage. Ces dernières années, le concept de paysage a fait l’objet d’une attention croissante de la part d'universitaires et d'experts appartenant à différentes disciplines. Au cours du XXe siècle, ce concept a connu une importante évolution au contact de ces disciplines ; en résulte ce que l’on nomme aujourd’hui le paysage urbain historique, qui est « le résultat d’une stratification historique de valeurs et caractères culturels et naturels qui vont au-delà de la notion de centre historique ou ensemble, jusqu'à inclure le contexte urbain le plus large et son emplacement (setting) géographique » (ajouter référence). Prenant en compte les perceptions et relations visuelles, les pratiques et valeurs sociales et culturelles, les processus économiques et les dimensions immatérielles du patrimoine liés à la diversité et l'identité des différentes cultures locales, l'approche du paysage urbain historique soutient les communautés dans leur quête de développement et d'adaptation, tout en conservant les caractéristiques et les valeurs liées à leur histoire, leur mémoire collective et leur environnement. Dès l’entre-deux-guerres, plusieurs personnalités ont abordé le problème des sites à partir de domaines jusque là distincts au profit d’une vision globale, liant les instances historique et esthétique de la ville et donc, la protection et la restauration du patrimoine et celle du paysage. Avec d’autres personnalités remarquables, tel Charles Buls, l’architecte-paysagiste Louis Van der Swaelmen a joué, dans le contexte belge, un rôle essentiel dans cette évolution de la culture de la conservation de la seule prise en compte des monuments à celle de la dimension urbaine. Avant tout connu comme planificateur et architecte-paysagiste urbain dans le cadre du Mouvement Moderne – dont il a été l'un des promoteurs –, Louis Van der Swaelmen est l’auteur des premières cités-jardins belges dans le premier tiers du XXe siècle. A ce jour, il est considéré comme l'un des acteurs principaux de la reconstruction d'une Belgique en grande partie détruite par l'artillerie allemande. En effet, après une période d'exil aux Pays-Bas lors de la Première Guerre mondiale, il rassemble une abondante documentation qui servira de base théorique non seulement aux travaux de reconstruction, mais aussi au développement du nouveau. En revanche, il est peu connu pour sa mobilisation en faveur de la protection et de la conservation des sites. Pourtant, on peut affirmer que Louis Van der Swaelmen fait partie des architectes qui ont conduit au changement de l'image du paysage belge, à un moment significatif de l'histoire architecturale nationale et européenne. L'objectif de cette étude a été non seulement d'examiner la figure de Louis Van Der Swaelmen en tant qu’architecte-paysagiste, personnalité émergente dans le contexte du développement urbain et précurseur du Mouvement Moderne belge, mais surtout de restituer sa culture architecturale et sa pensée dans le contexte national et international de la conservation, avec l’émergence de l’intérêt pour les sites et paysages. L’oeuvre de Van de Swaelmen se développe à une période particulière de l'histoire de la Belgique, où la construction d’une identité, notamment à travers la formation d’un esprit artistique national, est essentielle. Sur la scène internationale, les bases d'une conservation des sites, étroitement liés à l'évolution de la société dans son ensemble, ont été posées. Les contributions théoriques liées à la période complexe de la seconde moitié du XIXe siècle jusqu'aux années 1930 ont été essentielles, avec la conférence d'Athènes de 1931 et le Congrès du CIAM de 1933. Parmi celles-ci émergent les réflexions de Victor Hugo en France, de Goethe en Allemagne, de John Ruskin et du mouvement Arts and Crafts de William Morris en Grande-Bretagne, les études sur la culture historique de l'espace urbain de Camillo Sitte, la théorie du Kunstwollen de Alois Riegl ou encore les progrès dans le domaine de l'esthétique allemande de Gottfried Semper et les théories de Friedrich Theodor Vischer. Toutes ces expériences ont contribué, d'une façon plus ou moins visible, à l'évolution des mécanismes d’élaboration des directives internationales dans le domaine de la conservation et de la protection des centres historiques et du paysage. On peut donc considérer que Louis Van der Swaelmen a été formé dans un contexte très stimulant, non seulement par les contributions européennes dans le domaine de la conservation, mais aussi par les influences importantes anglaises, françaises, allemandes et néerlandaises qui ont marqué, après la Première Guerre mondiale, le monde de la planification urbaine et de la conservation dans le contexte belge. L’étude a été également l’occasion de comprendre et définir les points de contact entre les théories de conservation et celles de l'urbanisme, qui aujourd'hui, selon une vision simpliste de la réalité, sont considérées dans certains cas comme éloignées voire opposées. L'un des objectifs a été, par conséquent, contribuer à l'idée qu'au contraire, l’acte de la conservation et le projet du nouveau (soit en milieu urbain ou non), ne sont que des moments différents et complémentaires du même acte culturel. [less ▲]

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See detailL'art de la médiation scolaire. Entre ambiguïté et interprétations
Dethier, Baptiste ULg

Doctoral thesis (2017)

La thèse porte sur la construction de la politique de médiation scolaire menée en Belgique francophone et sa mise en œuvre concrète par de nouveaux agents chargés de l’interpréter : les médiateurs ... [more ▼]

La thèse porte sur la construction de la politique de médiation scolaire menée en Belgique francophone et sa mise en œuvre concrète par de nouveaux agents chargés de l’interpréter : les médiateurs scolaires. Dans un milieu scolaire où les acteurs, internes et externes aux établissements, sont multiples, les médiateurs sont appelés à prendre en charge des problèmes scolaires tels que la violence, le décrochage et l’absentéisme dans un cadre ambigu et, par conséquent, sujet à interprétation. La thèse rend compte du contexte organisationnel dans lequel les médiateurs s’inscrivent et de la mise en œuvre de cette politique. Baptiste Dethier analyse leur travail à l’aide de la métaphore du travail « artistique », c’est-à-dire comme un ensemble de procédures, de connaissances et de règles encadrant l’exercice d’une activité créative. Tout d’abord, cette activité est construite à partir d’orientations de sens – et non de prescriptions – données par l’État, les médiateurs scolaires étant chargés de les interpréter, grâce à une autonomie partiellement contrôlée. Ensuite, ces interprétations sont analysées grâce aux discours des médiateurs, reflétant la forte hétérogénéité dans la mise en œuvre de la politique de médiation scolaire ainsi que les controverses qui animent en permanence la fonction de médiateur. Enfin, à travers l’analyse des pratiques concrètes des médiateurs, il apparaît qu’elles consistent : d’une part, en la création de mises en scène spécifiques destinées à produire chez les bénéficiaires un état particulier de sensibilité ; d’autre part, comme autant de mises à l’épreuve de leur intégrité « artistique » et des principes dont ils se revendiquent. La thèse montre que les médiateurs scolaires se distinguent moins par ce qu’ils font que par la façon dont ils en parlent. Dès lors, la place de la place de la médiation et de la fonction de médiateur dans la division du travail au sein des organisations scolaires est questionnée. Celle-ci s’y trouve éclatée et ambigüe, entre contre-culture bousculant les équilibres historiques du système et participation au maintien de la forme scolaire traditionnelle. [less ▲]

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See detailImpact of spatio-temporal sahde on crop growth and productivity, perspectives for temperate agroforestry
Artru, Sidonie ULg

Doctoral thesis (2017)

Currently, silvoarable agroforestry is receiving renewed interest in Europe, as a land use system that allows for combining the production of commodities with a range of non-commodity outputs, such as ... [more ▼]

Currently, silvoarable agroforestry is receiving renewed interest in Europe, as a land use system that allows for combining the production of commodities with a range of non-commodity outputs, such as environmental protection. Despite the potential of this practice, it remains rarely implemented in Northwestern Europe. One of the obstacles in the adoption of silvoarable agroforestry systems is the lack of quantitative knowledge on the long term performance of different crops when they are competing for resources with trees. In the face of a wide range of possibilities, it remains difficult to obtain a clear overview of overall system functioning. In this thesis, we simplify this complexity by focusing our research questions on the resource of light, based on the assumption that in Belgian climatic conditions light is likely to be the predominant constraint for understorey crops in a silvoarable agroforestry system. With regard to this resource, we develop our research in order to gain insights into the growth mechanisms and final yield of shaded winter wheat and sugar beet crops. We address these questions using an artificial shade system, which has been developed to reproduce the effect of the heterogeneous spatio-temporal pattern of light observed under late-flushing trees in an agroforestry system, isolated from the competition effects for water and nutrients. The shade structures recreate two shade environments: continuous and periodic. The continuous shade treatment leads to shade throughout the entire day, while the periodic shade treatment induces an intermittent shade period, which varies during the day and according to structure orientation. Winter wheat responded to the late application of both shade treatments with a significant decrease in grain yield, which was partly compensated for by an increase in grain protein content. When shaded, sugar beet compensated through morphological adaptations of the aboveground part of the plant, and by a decrease in the final root dry matter and sugar yield. Overall, for both crops, the magnitude of the final yield repercussion varied with the level and period of shade application. Additionally, an arable plot bordered by a row of poplar trees was selected to evaluate the effect of real trees on the winter wheat. The reduction in the final grain yield follows a gradient, from underneath the trees to the centre of the field. Notwithstanding that interactions other than light competition may have occurred, the maximum yield reduction observed under the trees never reaches the level of decrease which is observed under the continuous shade treatment simulated by the artificial shade arrangement. This experimental approach with winter wheat was complemented by a modelling study, in which we evaluate the ability of the STICS crop model to simulate crops growing under dynamic shade. The results highlight the limits of the STICS model when it is used to simulate crop growth under contrasted shade conditions. Finally, we propose agroecology as a conceptual framework for developing sustainable and profitable agroforestry systems in Europe, and reflect on agricultural practices, food systems, and research methodologies. [less ▲]

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See detailEtude de la gestion des ressources génétiques ovines et caractérisation de leurs marchés en région périurbaine de Ouagadougou, Burkina Faso
Tindano, Kisito ULg

Doctoral thesis (2017)

Sheep production in Burkina Faso supplies internal consumption and exportation markets, in countries of West Africa (Côte d’Ivoire, Ghana, Nigeria, and Benin). In this region, sheep have both economic and ... [more ▼]

Sheep production in Burkina Faso supplies internal consumption and exportation markets, in countries of West Africa (Côte d’Ivoire, Ghana, Nigeria, and Benin). In this region, sheep have both economic and socio-cultural importance. While production is mainly located in the rural area, it is nevertheless noted that suburban livestock is developing, in particular around the capital city of Ouagadougou. Suburban production differs from rural livestock production, in particular by the actors involved, the economic orientation of production as well as by the availability of resources and production factors (services, inputs, land and capital). This context leads to the search for genetic resources favourable to this environment production, allowing for an optimisation of the activity. This implies a specific management of these resources. However, there is no information on how farmers in the suburban area manage their sheep genetic resources and on the sustainability of this management. Aiming to fill this information gap, this work focuses on (i) the characteristics of sheep farms in Ouagadougou suburbs and in neighbouring rural areas, (ii) the sheep traits, that have an impact on the their price, and finally (iii) the relative importance of some traits in the choice of breeding ram by breeders. In order to characterise sheep farming in the suburban area of Ouagadougou in terms of socio-economic motivations, breeding practices, including genetic resources management, and in order to better understand the dynamics of the sector, a survey was conducted among 80 breeders in the area. The results showed that the sector essentially comprises two categories of livestock, with almost half (42.5%) of the breeders who can be described as traditional livestock keepers. The latter breeders are illiterate at 94.1% and have no non-agricultural economic activities (88.2%). They don’t have sheltered enclosures (70.6) and their sheep don’t receive systematic deworming (61.8%). They keep Mossi sheep (88.2%) and their main selection objective is rusticity (64.7%). The other category includes 50% of the livestock keepers. These tend to intensify production through the use of better infrastructures (enclosures, shelters), better feeding and systematic de-worming of animals (87.5%). They report keeping animals for generation of additional income and they practice crossbreeding. Their main selection objective is to improve the young growth and adult weight. Reproduction is generally characterised by a lack of mating control, especially during the dry season when the animals are allowed to graze freely. This phenomenon, in the context of the practice of crossbreeding by some breeders, creates negative externalities for breeders preferring the purity of their herd for rusticity motives. This also undermines the sustainability of the systems by an uncontrolled increase in the share of Fulani genetics in herds and the loss of sources of Mossi pure breed. To investigate the possibility for the rural area to constitute a source for purebred Mossi sheep for the suburban area, another survey was conducted among 63 livestock keepers in the region of the Central Plateau of Burkina Faso. This study showed that sheep in this area are kept in sedentary systems and the Mossi sheep is the most encountered. A selective breeding strategy can be found for all breeders through the choice of males. The most cited selection objectives were the improvement of the adult weight (84.1%), the young growth (79.4%) and the maintenance of the rusticity (73%). In agreement with their goal of improving the weight and growth of animals, Mossi sheep females are often crossed with Fulani ram. These males are eliminated from the herd after the birth of the first crossbred lambs, while the latter are subsequently used for breeding. By removing the Fulani males after a short period of use, management appears to be better mastered and more sustainable compared to the suburban area, but leads to reconsider the notion of "purebred" in the region, as the management of breeders includes the mixed use of available breeds. However, with regard to the use of this area as a source of replacement females, if farmers appear to be willing to sell females to other farmers, the size of their herds doesn’t allow the sale of large numbers because of their own replacement needs. Added to this is the tendency expressed by some farmers to only sell to farmers they know, in hopes of reciprocity, hence for social rather than commercial motives. Consumer market demand for different phenotypic traits was investigated through a monitoring of market transactions (revealed preference surveys) and surveys among sheep exporters and butchers. A total of 338 transactions were monitored over three different periods (the Muslim Eid al-Adha feast period, Christmas and New Year period and a neutral period). The interviews involved 25 exporters and 15 butchers, who were asked about the characteristics of the animals quested for and their purchase localities. Survey results showed that exporters have preferences for large-framed and good body conditions animals while local butchers mark their preferences for small-framed and low-fitness animals. Markets are categorised into collection, assembly and terminal markets through which animals pass before reaching the final consumer. The revealed preferences have shown that phenotypic traits such as coat colour, weight and height at the withers have a highly significant (p<0.001) influence on prices. The weight has shown a non-linear, increasing influence on prices with increasing marginal income per kg of live weight. The purchase period, which is embedded with the purchase motive, also showed a highly significant (p<0.001) influence on prices, showing a superiority of the prices during the Eid al-Adha, but no difference between prices during the Christmas and New Year period and the neutral periods. Finally, the purchase period and coat colour showed highly significant interactions with the weight, the white-coloured animals and the Eid al-Adha period having better valorised the increase in weight. This study sheds light on the links between markets and demands for a certain orientation of sheep genetic resources. It is suggested, for example, that an improvement on the basis of higher weight and white colour criteria, which are more valued on the market, would rather favour a niche market linked to feasts periods and exports, and some breeders benefiting improved livestock resources. On the contrary, an improvement towards rusticity for small-framed animals would supply a more ordinary market, contributing to food security of households and an income generation for a wider range of sheep producers. In this market context, a final study aimed at highlighting the trade-off that breeders are willing to make for the improvement of the different traits, whether "productive" or "adaptive". A stated choice experience, taking into account the traits such as weight, colour, susceptibility to diseases and the feed requirement, was carried out with 137 breeders. These farmers mainly use natural grazing (82.5% of the farmers involved). Crossbreeding is observed in 23.4% of farmers. The highest willingness to pay (WTP) was observed for resistance to diseases with 261€. However, among the farmer practicing crossbreeding, there was an apparent preference for susceptibility to disease with a WTP of 45€. A significant WTP was also revealed for the white coat colour (21€) then preferred to the bicoloured. The preference for large-framed animals compared to medium-framed ones was significant but relatively lower than preferences for white coat colour and resistance to diseases. On the other hand, farmers showed indifference for the transition from the medium body size to the small body size. For all traits, farmers practicing crossbreeding showed a preference for extreme levels compared to intermediate levels. Two trends emerged from this study: on the one hand, farmers willing to take the risk of reducing resistance to diseases in order to increase productivity; on the other hand, those with greater risk aversion, strongly willing to spend to gain resistance to diseases. The case of crossbreeding farmers suggests an interesting double preference, demonstrating a WTP for opposed traits being considered as typical of one breed or the other, then depreciating the intermediate traits indicating the possibility of a crossbred. All the studies indicate that the management of sheep genetic resources in Ouagadougou's suburban area, although it does not really present threats to the different breeds in its present state, nevertheless shows signs, particularly from the market, that could hamper the sustained use of small-framed and environmentally adapted sheep. It is therefore necessary to find a strategy to better organise this management to make it sustainable. The establishment of a terminal crossbreeding scheme involving suburban and rural livestock farmers is a possible strategy. This nevertheless requires truly commercial livestock at the end of the scheme and means to overcome certain constraints raised in this thesis. [less ▲]

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See detailDroplet microfluidics for single-cell manipulation
Van Loo, Stéphanie ULg

Doctoral thesis (2017)

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See detailMulti-instrument study of the hourly pulsations in Saturn's magnetophere
Palmaerts, Benjamin ULg

Doctoral thesis (2017)

The exploration of the magnetospheres of Jupiter and Saturn has revealed various periodic processes. Some periodicities are related to the planetary rotation while some others are characterized by a short ... [more ▼]

The exploration of the magnetospheres of Jupiter and Saturn has revealed various periodic processes. Some periodicities are related to the planetary rotation while some others are characterized by a short period. In Saturn's magnetosphere, periodicities of about one hour have been reported in the measurements of charged particle fluxes, plasma wave emissions, magnetic field strength and auroral emission brightness. The frequency, the spatial distribution and the magnetospheric process generating these hourly periodicities are still unknown. Similar short-period pulsations have been also observed in Jupiter's magnetosphere, suggesting that these 1-hour periodicities are the signature of a fundamental process in the magnetospheres of these two giant planets. In this thesis, I performed a thorough analysis of these hourly periodicities at Saturn using the data sets of several instruments on board the Cassini spacecraft in orbit around the giant planet since 2004. First I made a survey of the quasi-periodic 1-hour energetic electron pulsations observed in Saturn's magnetosphere between 2004 and 2014 by the Cassini particle instrumentation. These pulsations appear in the electron fluxes at energies between a hundred keV up to several MeV. The survey includes 720 pulsed electron events observed in the outer magnetosphere over a wide range of latitudes and local times, revealing that this phenomenon is common and frequent in Saturn's magnetosphere. A statistical analysis on the morphological properties of the pulsed events suggests a high-latitude source for the pulsed energetic electrons. I also investigated the simultaneous signatures of the electron pulsations in the radio emissions and the magnetic field measured by Cassini. The results of the multi-instrument study support the scenario of a high-latitude electron source and suggest a possible relation with the auroral processes. Images of Saturn's auroral emissions, which display the ionospheric response to magnetospheric dynamics, have been investigated to highlight any hourly pulsations. A high-latitude auroral spot exhibits quasi-periodic brightening with a periodicity of around 60 minutes. This auroral spot is associated with the magnetospheric cusp and high-latitude magnetopause reconnection in the lobes. Pulsed dayside magnetopause reconnection is likely a common triggering process for the cusp auroral brightening and for the high-latitude energetic electron pulsations. Finally, analysis of the plasma environment with low-energy electron measurements provided evidence of the presence of energetic electron pulsed events in the close vicinity of the magnetopause. Therefore it is suggested that processes at the magnetopause, most likely magnetic reconnection induced by instabilities, generate the hourly electron pulsations located at low latitude. The multi-instrument study achieved in my thesis sets constraints on the origin of the pulsed electron events and bring forward our current understanding on the hourly pulsations in Saturn's magnetosphere. [less ▲]

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See detailRégulation de voies de signalisation par deux acteurs de la voie Nonsense-mediated Decay, Dhx34 et Nbas: la cas particulier de l'adénohypophyse.
Windhausen, Thomas ULg

Doctoral thesis (2017)

In eukaryotes, biosynthesis of functional mRNAs is the core process of genetic expression and is monitored by highly conserved pathways that prevent appearance of aberrant mRNAs. Amongst them the Nonsense ... [more ▼]

In eukaryotes, biosynthesis of functional mRNAs is the core process of genetic expression and is monitored by highly conserved pathways that prevent appearance of aberrant mRNAs. Amongst them the Nonsense-Mediated Decay (NMD) pathway is the surveillance mechanism that detects and degrades mRNAs containing premature termination codons (PTCs). The translation of transcripts containing such nonsense codon within the coding sequence would leads to the production of C-terminally truncated proteins that could exhibit dominant negative or gain-of-function activities. The NMD is thus a key determinant of the phenotypic outcome of numerous diseases involving PTCs such as the β-thalassemia, the Duchenne muscular dystrophy or even some cancers. In addition to its quality control function degrading aberrant mRNA, the NMD is also involved in the abundance regulation of several physiological transcripts. For example the NMD is involved in the regulation of the concentration of splicing factors in a process called AS-NMD (Alternative splicing- Nonsense-mediated Decay), establish a threshold for some stress responses such as the UPR pathway (Unfolded Protein Response) and constitute a defence mechanism against ARN(+) viruses. Despite tremendous studies, the study of the developmental and physiological impact of the NMD pathway is restrained due to the early lethality of the mammals embryos that underwent knock-out of one of the NMD actor. As an alternative model we propose Danio rerio which as a vertebrate with external development and a large panel of genetic inactivation methods is a wonderful model for developmental studies and represent a excellent tool to study the NMD pathway. Initial studies in zebrafish conducted by morpholino knock-down, showed that depletion of upf1, upf2, smg5, smg6, dhx34 or nbas leads to the NMD blockage and induce similar developmental defects mainly in brain, eyes and somites. Moreover, it’s has been showed that as in mammals the NMD in fish also implicated in the regulation of natural transcripts. We present here a functional study of two key actors of the NMD, Dhx34 and Nbas, in the interesting case of the pituitary gland development. In the present study, we shed light on the NMD pathway importance for the developmental process of the pituitary gland. Using in situ hybridization confirmed by RT-qPCR quantification, we observed that the NMD inactivation thought inhibition of two crucial actors of this surveillance pathway, Dhx34 and Nbas, lead to a hypertrophy of the gland coupled with a promotion of the anterior cell fates and a repression of the posterior fates at 2 dpf. We proved that this endocrine deregulation is due to a late general increase of the Sonic Hedgehog and Delta-Notch signalling during AH formation. In addition to previous works, our results show that the NMD pathway is required to control the activity diverse signalling pathways involved in the developmental process. As confirmation, we could observe serious abnormalities in a variety of tissues such as underdeveloped eyes, intestine, liver and skeleton, defects in brain, somites and vascular patterning. [less ▲]

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See detailDesign and Management of Freight Transport Networks: Intermodal Transport and Externalities
Mostert, Martine ULg

Doctoral thesis (2017)

Transportation of goods contributes to the economic development of societies but it generates negative impacts on its environment called negative externalities. In its White Paper on Transport, the ... [more ▼]

Transportation of goods contributes to the economic development of societies but it generates negative impacts on its environment called negative externalities. In its White Paper on Transport, the European Commission encourages the flow transfer from road to more environmentally friendly modes like rail or inland waterways (IWW). This objective can be reached by the development of intermodal transport. A literature review on transport externalities and their valorization methods highlights the small number of studies related to the general modeling of transport externalities through dedicated mathematical formulas. However, the latter are important for identifying the key parameters that influence transport competitiveness in terms of externalities. This is demonstrated by analyzing two external cost functions for road and rail. The location of intermodal terminals stands out from the environmental perspective as one of the most important competitiveness factors of intermodal transport regarding road. An innovative mathematical model for the location of terminals and allocation of flows between road and intermodal rail and IWW transport is developed. The model is based on a bi-objective formulation which evaluates the trade-offs between transport operational costs and CO2 emissions. Economies of scale of intermodal transport are integrated. The model is applied to the Belgian network. Results indicate that terminal locations are relatively stable, whatever the optimized economic or environmental objective. The type of terminal located changes according to the followed strategy. Minimizing CO2 emissions leads to an increased use of intermodal transport. The impact of transport on air pollution is also evaluated. On the Belgian case, an economic optimization of transport operational costs is compared to an environmental optimization of transport air pollution external costs. The intervention of public authorities through a taxation policy for trucks is also studied. Results show that the introduction of road taxes leads to a more intensive use of intermodal transport than in the absence of taxes. The maximum intermodal market share is observed when air pollution external costs are minimized. Finally, a new model which considers other intermodal chains than the traditional “road-rail/IWW-road” modeling is applied on experimental data at the European level. The model allows to choose between any direct transport by one mode (road, rail or IWW), and any intermodal transport of up to three modes. Results indicate that several connections may benefit from the use of other combinations of modes than the “road-rail/IWW-road” combination. [less ▲]

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See detailDevelopment of non-linear Electro-Thermo-Mechanical Discontinuous Galerkin formulations
Homsi, Lina ULg

Doctoral thesis (2017)

A coupled Electro-Thermo-Mechanical Discontinuous Galerkin (DG) method is developed considering the non-linear interactions of electrical, thermal, and mechanical fields. The numerical properties of the ... [more ▼]

A coupled Electro-Thermo-Mechanical Discontinuous Galerkin (DG) method is developed considering the non-linear interactions of electrical, thermal, and mechanical fields. The numerical properties of the DG are demonstrated, such as uniqueness, consistency, stability and the optimal convergence rate. The framework is applied to simulate the response of smart composite materials, where the shape memory effect is triggered by the Joule effect. [less ▲]

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See detailApplication of wavelet transforms to geosciences: Extraction of functional and frequential information
Deliège, Adrien ULg

Doctoral thesis (2017)

It is now well-known that there exist functions that are continuous but nowhere differentiable. Still, it appears that some of them are less “irregular” than others. The pointwise regularity of a function ... [more ▼]

It is now well-known that there exist functions that are continuous but nowhere differentiable. Still, it appears that some of them are less “irregular” than others. The pointwise regularity of a function can be characterized by its Hölder exponent at each point. For the sake of practicability, it is more appropriate to determine the “size” of the sets of points sharing a same exponent, through their Hausdorff measure. By doing so, one gets the multifractal spectrum of a function, which characterizes in particular its monofractal or multifractal nature. The first part of this work is based on the so-called “wavelet leaders method” (WLM), recently developed in the context of multifractal analysis, and aims at its application to concrete situations in geosciences. First, we present the WLM and we insist particularly on the major differences between theory and practice in its use and in the interpretation of the results. Then, we show that the WLM turns out to be an efficient tool for the analysis of Mars topography from a unidimensional and bidimensional point of view; the first approach allowing to recover information consistent with previous works, the second being new and highlighting some areas of interest on Mars. Then, we study the regularity of temperature signals related to various climate stations spread across Europe. In a first phase, we show that the WLM allows to detect a strong correlation with pressure anomalies. Then we show that the Hölder exponents obtained are directly linked to the underlying climate and we establish criteria that compare them with their climate characteristics as defined by the Köppen-Geiger classification. On the other hand, the continuous version of the wavelet transform (CWT), developed in the context of time-frequency analysis, is also studied in this work. The objective here is the determination of dominant periods and the extraction of the associated oscillating components that constitute a given signal. The CWT allows, unlike the Fourier transform, to obtain a representation in time and in frequency of the considered signal, which thus opens new research perspectives. Moreover, with a Morlet-like wavelet, a simple reconstruction formula can be used to extract components. Therefore, the second part of the manuscript presents the CWT and focuses mainly on the border effects inherent to this technique. We illustrate the advantages of the zero-padding and introduce an iterative method allowing to alleviate significantly reconstruction errors at the borders of the signals. Then, we study in detail the El Niño Southern Oscillation (ENSO) signal related to temperature anomalies in the Pacific Ocean and responsible for extreme climate events called El Niño (EN) and La Niña (LN). Through the CWT, we distinguish its main periods and we extract its dominant components, which reflect well-known geophysical mechanisms. A meticulous study of these components allows us to elaborate a forecasting algorithm for EN and LN events with lead times larger than one year, which is a much better performance than current models. After, we generalize the method used to extract components by developing a procedure that detects ridges in the CWT. The algorithm, called WIME (Wavelet-Induced Mode Extraction), is illustrated on several highly non-stationary examples. Its ability to recover target components from a given signal is tested and compared with the Empirical Mode Decomposition. It appears that WIME has a better adaptability in various situations. Finally, we show that WIME can be used in real-life cases such as an electrocardiogram and the ENSO signal. [less ▲]

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See detailDesign of reprocessable poly(ɛ-caprolactone)-based shape-memory materials
Defize, Thomas ULg

Doctoral thesis (2017)

Shape-memory polymers (SMPs) are remarkable materials able to switch from a temporary shape to their initial permanent shape by crossing a thermal transition, e.g. glass or melting transition. Efficient ... [more ▼]

Shape-memory polymers (SMPs) are remarkable materials able to switch from a temporary shape to their initial permanent shape by crossing a thermal transition, e.g. glass or melting transition. Efficient shape-memory effect is notably observed for chemically cross- linked semi-crystalline polymers. Chemical networks of semi-crystalline poly(ε-caprolactone) (PCL) are widely studied for the development of SMPs especially when biomedical applications are foreseen. As these SMPs are irreversibly cross-linked material, their (re)processing is quite limited since they cannot be molten or solubilized after cross-linking. This prevents any recycling. Thereby, using reversible cross-linking reactions allowing the formation or cleavage of the network upon a selected stimulus raise tremendous interest for the development of smart SMPs. Chemically cross-linked but remarkably (re)processable shape-memory polymers (SMP) were designed by crosslinking poly(ε-caprolactone) (PCL) stars via reversible cycloaddition reactions. The thermo-reversible Diels-Alder (DA) reaction between furan and maleimide was investigated to crosslink the PCL matrix. However, the relatively low retro DA temperature of the furan-maleimide adducts led to some inelastic deformation during shape memory tensile cycles. In order to get rid of this drawback, two alternative approaches were investigated, i.e. the substitution of the DA reaction firstly by the efficient triazolinedione click chemistry, especially the very fast and reversible Alder-ene reaction of 1,2,4-triazoline-3,5- dione (TAD) with indole compounds and secondly by a photo-reversible reaction, typically the photo-induced (2+2) cycloaddition of coumarins. With these networks, the typical shape memory properties of PCL networks (high fixity and recovery ratios) were preserved while upon an external (light or stress) stimulus, the PCL network can be (re)processed efficiently. [less ▲]

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See detailEtude descriptive et relationnelle des facteurs de risque d’infécondité et d’infertilité des vaches laitières au sud Viet Nam
Nguyen, Kien Cuong ULg

Doctoral thesis (2017)

Increasing milk production is a key issue for Vietnam. Improving milk production involves controlling direct or indirect factors responsible for this. These factors are genetics, feed, environment, and ... [more ▼]

Increasing milk production is a key issue for Vietnam. Improving milk production involves controlling direct or indirect factors responsible for this. These factors are genetics, feed, environment, and reproductive performance. The identification and control of individual or collective factors responsible for reproductive performance is therefore an important step in improving milk production. The general objective of our study is to describe the milk and reproductive performances of dairy smallholding in Vietnam and to analyze the effects of risk factors on reproductive performance. The specific objectives are:(1) to describe the physiological and pathological characteristics of genital tract of culled dairy cows in dairy smallholding; (2) to specify the fecundity and fertility of heifers and dairy cows of small dairy farms; (3) to identify the postpartum (PP) reproductive disorders of cows in dairy smallholders (4) to analyze the effects of individual and environmental risk factors on the reproductive performance of heifers and cows; and (5) to analyze the risk factors for the postpartum (PP) reproductive disorders of cows. The first work of our study was conducted from February to August 2012 on 507 culled crossbred Holstein Friesian (HF) x Lai Sind (LS) dairy cows at two slaughterhouses in HCMC. Age and body condition score (BCS) of cows were determined prior to slaughter. A visual examination of vulva region was also performed to identify the presence of eventual discharges. Then, vaginoscopic examination was performed to determine the presence of discharges and pneumovagina or even urovagina. After slaughter, the uterus was incised to examine the contents. Oviducts were observed to identify abnormalities. The ovaries were collected to evaluate eventual structures (number and diameter of follicles, corpus luteum - CL and cysts) using an ultrasound (KX5200, 6.5 MHz linear probe). The results of this study revealed some important pathological characteristics of examined cows. Nearly half (44.4%) of examined cows had a BCS lower than 2.5. The prevalence of pneumovagina and urovagina was 33.1% and 14.7%, respectively; age and BCS have had a significant effect on the prevalence of these pathologies. The frequencies of vaginal discharges and abnormal uterine contents were 12.1% and 5.4%, respectively. 226 out of 507 examined cows (44.6%) were in anœstrus. The frequencies of functional pathological anœstrus, cystic, pyometral and gestation were 37.3%, 2.0%, 0.4% and 4.9%, respectively. Type 0 and I anœstrus have been more often observed in cows with low BCS and in cows aged less than 6 years. The results of the first work reinforced us in the need to set up specific monitoring of small dairy farms at HCMC. The total of 232 heifers and 244 cows (261 lactations) of 35 small farms in Cu Chi district, HCMC were observed during the years 2013 and 2014. The animals are kept permanently indoors. Their diet consists of fodder (Pennisetum purpureum or natural grass and rice straw), concentrates and by-products (spent grain and cassava waste). Each farm was monitored monthly for reproduction of heifers and cows by transrectal palpation, ultrasound (KX5200, 6.5 MHz linear probe) and vaginoscopy. Reproductive data (dates and type of calving, calf sex, complications, results of clinical examinations, date of heat, date of insemination), milk production (daily average milk yield per cow), BCS and weight of heifers were updated at each visit. The reproductive performance was assessed by fecundity and fertility parameters. The fecundity of heifers and cows was calculated by (1) birth to conception interval (heifers) (or age at conception – AC) or calving to conception interval (cows) (or days open - DO), (2) birth to first service (heifers) (or age at first service – AFS) or calving to first service (cows) (or waiting period - WP) and (3) days between first and last service (DFLS). The fertility of heifers and cows was determined by (1) number of services per conception (NSC), (2) conception rate at first service (CRFS) and (3) overall conception rate (CR). The prevalence of PP disorders (dystocia, retained placenta or RP, clinical endometritis, urovagina, cysts and anœstrus) was also determined. The monthly temperature and humidity index (THI) for the years 2013 - 2014 has been calculated. The body weight and average daily gain of heifer at 6, 12 and 16 months of age were 159, 280 and 351 kg and 690, 646 and 705 g/day respectively. The average daily milk yield per cow was 11.6 (± 0.5) kg. The average duration of lactation was 368 (± 100) days. The overall mean of AFS, DFLS and AC of heifers was 479 (± 80), 38 (± 80) and 517 (± 114) days, respectively. The NSC, CR and CRFS was 1.8 (± 1.4), 55% and 58%, respectively. A significant decrease in AFS and AC according to the year of birth and a significant increase in AFS with a heavier weight (> 320 kg) at first AI were observed. CRFS of heifers inseminated in 2013 was higher than that of heifers inseminated in 2014 (64% vs 50%, P <0.05). The monthly CR in heifers was negatively correlated with the monthly THI during observed period (P = 0.003). The overall mean of WP, DFLS, DO of cows was 109 (±52), 133 (±114) and 242 (±129), respectively. The mean for NSC, CR and CRFS was 4.3 (±2.7), 23 % and 14 %. A significant decrease in WP, DFLS, DO and NSC with an increase according to the year of calving was observed in this study. Calving occurring during rainy season was accompanied by a significant increase in WP. The presence of PP disorders was accompanied by an increase in WP (108 vs 98 days), DO (249 vs 216 days) and NSC (4.7 vs 3.9). A decrease in BCS between calving and day 60th (C60) and between day 60th and 120th PP resulted in a significant increase in WP and DO. The decrease in BCS between C60 also leaded to a significant reduction in CRFS (8 vs 18%, P <0.05). The year and season of insemination, and the BCS at insemination had a significant effect on the NSC and CR of cows. There was a negative correlation between monthly CR in cows and THI (r = -0645, P = 0.02). A total of 353 calvings and PP periods of 302 cows were observed. The prevalence of dystocia, RP, clinical endometritis, urovagin, PP anestrus and ovarian cysts was 24.4%, 16.4%, 19.2%, 5.6%, 49.9% and 6.3%, respectively. The primiparous cows had 1.7 times more risk of dystocia than the multiparous cows (29.9% vs 20.4%, P <0.05). Cows that calved in 2014 or in rainy season had 6 or 2.1 times more than risk of dystocia than cows that calved in 2013 (P <0.001) or in dry season (P <0.01), respectively. The frequency of RP was higher in 2014 than in 2013 (21.8% vs. 11.7%, P <0.01). Cows that calved in 2014 or in rainy season showed more frequently clinical endometritis than cows that calved in 2013 (OR = 3.03, P = 0.001) or in dry season (OR = 3.78, P <0.001). Dystocia (OR = 2.8; P = 0.003) and RP (OR = 4.7, P = 0.001) were the major risk factors of clinical endometritis. The difficult calving, clinical endometritis and insufficient BCS at calving (< 3) or day 30th in PP were accompanied by an increase in risk of type I anestrus. In conclusion, the reproductive performance was satisfactory for heifers, but poor for cows. The infertility and PP anestrus are the major factors responsible for this situation. Heat stress and under-nutrition are the major causes of infertility and PP anestrus. Moreover, the frequency of reproductive disorders (dystocia, RP, clinical endometritis and PP anestrus) is also important in this study. Dystocia and RP are the risk factors for clinical endometritis and this disorder also had a negative effect on fertility and resumption of ovarian activity in cows. [less ▲]

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See detailNouvelles combinaisons thérapeutiques pour améliorer l'efficacité anti-tumorale de l'inhibition d'HDAC5
Hendrick, Elodie ULg

Doctoral thesis (2017)

En oncologie, les 18 membres de la famille des déacétylases d’histone (HDAC) représentent des cibles thérapeutiques d’intérêt croissant. En effet, de nombreuses molécules pharmacologiques ciblant ... [more ▼]

En oncologie, les 18 membres de la famille des déacétylases d’histone (HDAC) représentent des cibles thérapeutiques d’intérêt croissant. En effet, de nombreuses molécules pharmacologiques ciblant l’activité enzymatique de ces protéines (HDACi) montrent des effets anti-tumoraux intéressants in vitro et in vivo ainsi que dans de nombreux essais cliniques sur des patients souffrant de pathologies cancéreuses solides et hématologiques. A ce jour, 4 de ces molécules (Vorinostat®, l’Istodax®, Beleodaq® et le Farydak®) sont d’ailleurs approuvées par la FDA et l’EMA pour le traitement de patients souffrant, notamment, de différents types de lymphomes et de myélomes. Aujourd’hui, les oncologues s’intéressent au développement d’inhibiteurs d’HDAC plus sélectifs avec comme objectifs de maintenir et d’améliorer l’effet anti-tumoral tout en diminuant la toxicité et en réduisant les potentiels effets non désirés. Dans cette optique, il convient de déterminer plus finement les relations qu’il existe entre l’inhibition spécifique d’une HDAC et les effets anti- tumoraux observés et ce, afin d’identifier la (les) HDAC d’intérêt à cibler en thérapie anti-cancéreuse. Dans ce travail, nous nous sommes focalisés sur le rôle et les mécanismes d’action de l’histone déacétylase 5 (HDAC5) dans les cellules cancéreuses. Nos résultats démontrent que l’inhibition sélective d’HDAC5 module l’expression de protéines du complexe I de la chaîne respiratoire mitochondriale, de protéines pro- et anti- oxydantes et des protéines impliquées dans le métabolisme de métaux tel que le métabolisme de stockage du fer labile. Par conséquent, la déplétion d’HDAC5 induit une production accrue d’espèces réactives de l’oxygène (ROS) mitochondriaux accentués par la présence accrue de fer labile intracellulaire disponible pour la réaction de Fenton. Cette accumulation accrue de ROS induit une mort cellulaire par apoptose et un processus d’autophagie de type mitophagie (dégradation sélective des mitochondries endommagées et productrice de ROS). La déplétion d’HDAC5 dans des cellules cancéreuses modifie également le métabolisme énergétique dépendant du glucose et de la glutamine. Nous avons effectivement observé d’une part, une augmentation de l’import du glucose dirigé vers la voie des pentoses phosphates assurant une production de NADPH, force réductrice du glutathion permettant ainsi de contrecarrer le stress oxydant et d’autre part, une glutamino-dépendance nécessaire au maintien des besoins énergétiques de la cellule. Par conséquent, des cellules déplétées en HDAC5 dont l’apport en glucose ou en glutamine est contrecarré par des inhibiteurs métaboliques utilisés en clinique, meurent de manière significative par apoptose in vitro et diminuent la croissance de tumeurs in vivo, suggérant que des stratégies combinatoires couplant l’inhibition sélective d’HDAC5 à des inhibiteurs du métabolisme énergétique actuellement testés en essai clinique pourraient être proposées comme nouvelle stratégie combinatoire en thérapie anti-cancéreuse. [less ▲]

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See detailLes constructions relatives du néo-égyptien. Une approche fonctionnelle
Sojic, Nathalie ULg

Doctoral thesis (2017)

Cette dissertation doctorale se propose d’étudier les constructions relatives du néo-égyptien suivant une approche fonctionnelle. Elle offre une première étude large de la relativisation pour cet état de ... [more ▼]

Cette dissertation doctorale se propose d’étudier les constructions relatives du néo-égyptien suivant une approche fonctionnelle. Elle offre une première étude large de la relativisation pour cet état de langue sous l’angle de la variation linguistique. Elle comprend deux grandes parties : les chapitres 1 à 4 sont théoriques, les chapitres 5 à 9 constituent la recherche à proprement parler. Le chapitre 10 conclut l’ensemble. Le premier chapitre (Ch. 1) propose un état de la question des études relatives aux constructions relatives en égyptien ancien et met en avant le manque criant de vision d’ensemble des descriptions et des études proposées jusqu’à présent, tous états de langue confondus. Le chapitre suivant (Ch. 2) définit le cadre théorique dans lequel s’inscrit l’étude, à savoir les bases conceptuelles et terminologiques issues du fonctionnalisme en linguistique. J’y fais également le point sur le recours, en égyptologie, à ces théories. Le troisième chapitre (Ch. 3) est consacré à la délimitation et à la description du corpus, l’accent étant mis sur la variation linguistique (en diachronie et en synchronie dynamique). Je propose ensuite (Ch. 4) un préambule ou un excursus relatif à la définition des « parties du discours », catégories d’après lesquelles sont classées les unités qui composent la phrase. La plupart des études fonctionnelles, dont la présente, ont pour objet l’une de ces catégories. Le cinquième chapitre (Ch. 5) offre une vue d’ensemble des constructions relatives et constructions apparentées en égyptien ancien (ancien, moyen et néo). La description, très générale, vise à rendre compte de leurs principales caractéristiques typologiques et des particularités de la langue étudiée. Le chapitre suivant (Ch. 6) est consacré à l’histoire du système : il en présente les grandes tendances distributionnelles aux stades de la langue antérieurs au néo-égyptien. Cette synthèse montre l’existence de jeux d’oppositions à l’œuvre à une époque donnée et permet d’en constater l’évolution au stade concerné. Dans un autre chapitre, (Ch. 7) j’examine en détail l’expression de la négation dans les relatives. Après y avoir exposé les facteurs de variation spécifique à l’évolution de la négation, je propose une taxonomie fonctionnelle des constructions relatives négatives en néo-égyptien. Plus loin (Ch. 8), je me penche sur l’épineuse question de la valeur sémantique des relatives introduites par nty (« vraies » relatives) et de celles introduites par iw (relatives « virtuelles », c’est-à-dire des circonstancielles fonctionnant comme des relatives). Ma démarche, issue d’une réflexion critique à partir des études menées sur les différents types de relatives dans d’autres langues, m’amène à suggérer que, contrairement à ce qui a été dit pour l’égyptien ancien, leur distribution ne dépend pas uniquement de la définition de l’antécédent ou de la nature du relateur, mais que la valeur sémantique – contingente ou non – de la construction relativisée joue un rôle tout aussi important. Cette nouvelle façon d’aborder le problème permet d’apporter une explication quant à la grammaticalisation observée dans la distribution de ces constructions. L’avant dernier chapitre (Ch. 9) propose une étude approfondie de l’omission du pronom de rappel de l’antécédent dans les relatives du néo-égyptien. J’y recours aux concepts d’échelle d’accessibilité à la relativisation élaborée par Keenan & Comrie (1977), d’échelle d’accessibilité cognitive d’Ariel (1990) et aux travaux d’Hawkins (1999, 2004) relatifs à la structure informationnelle de la phrase complexe. Ce faisant, je définis des contextes particulièrement favorables à une omission, et démontre aussi que ces omissions sont en partie motivées par des facteurs extralinguistiques. Le dernier chapitre (Ch. 10) fait office de conclusion générale. Il fait le point sur l’apport des chapitres précédents et sur les différents types de variations mis en évidence dans cette étude. [less ▲]

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See detailCaractérisation des amidons de sorgho et de mil perlé cultivés dans le Sahara algérien
Boudries, Nadia ULg

Doctoral thesis (2017)

Starches of sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.)) cultivated in Tidikelt (In Salah) and Ahaggar (Tamanrasset), were the subject of a characterization study. The ... [more ▼]

Starches of sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.)) cultivated in Tidikelt (In Salah) and Ahaggar (Tamanrasset), were the subject of a characterization study. The approach consists of the isolation of starches, the determination of physico-chemical and functional properties and the study of enzymatic hydrolysis modification. The starches with a rate ranging from 63.1 to 66.8 % were isolated according to the alkaline method. The purity of the obtained starches is satisfactory (91.4-96.7 %).However the extraction yield remains average (59.1-61.2 %). The physical properties (color, shape and size of the granules), chemical composition (moisture, starch and amylose) and rheological properties (solubility, swelling power and viscosity) of the isolated starches were determined. Important results were obtained highlighting interesting functional properties of these starches. Indeed, the average diameter of native starches granules had reached 18 and 10µm for sorghum and pearl millet respectively. These values are lower than those of others regions cultivars and close to those of corn and cassava. The amylose content (23.0 and 27.1 %) revealed that the analyzed cereals are normal varieties. The analysis of viscosity showed a very high peak viscosity that is reached rapidly. The DSC analysis has revealed higher gelatinization temperatures, attributed to high maturity temperatures. The X-rays diffraction patterns show the type A characteristic of cereals and allowed deducing the relative degrees of cristallinity. The kinetic studies of hydrolysis showed that the sorghum and pearl millet starches present susceptibility for hydrolysis in presence of fungal, bacterial and human amylases. However, this susceptibility varies according to the treatment used with the integral grinding (flour) and to enzyme source. The experimental conditions allowing to enzymatic hydrolysis reactions of isolated starches to follow the Michaelis-Menten model were determined and kinetic constants (KM and Vmax) were calculated. The HPAEC-PAD profiles of oligosaccharides in sorghum starches hydrolysates were determinated for highlight the amylases activities. The study demonstrated the potential of sorghum and pearl millet starches and considers their applications and bioprocessing. [less ▲]

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See detailLes Hormones Glycoprotéiques: de la Clinique à la Recherche.
VALDES SOCIN, Hernan Gonzalo ULg

Doctoral thesis (2017)

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See detailGestion du changement organisationnel lié à la mise en oeuvre des TIC dans les Douanes africaines: Etude du cas du PVS dans les Douanes ivoiriennes.
N'Dri, Koffi Jacques ULg

Doctoral thesis (2017)

Given the importance of customs revenues in the budgets of African countries, the use of Information and Communication Technologies (ICT) in order to adapt techniques and methods of control to the needs ... [more ▼]

Given the importance of customs revenues in the budgets of African countries, the use of Information and Communication Technologies (ICT) in order to adapt techniques and methods of control to the needs of facilitation of international trade is a major challenge. In this context, this work investigates what become of the technical potentialities of ICTs when confronted to the contextual characteristics of the environment in which they are to be implemented. This is the main purpose of this research that is based on the study of the case of the PVS system in the Customs administration of Côte d’Ivoire. The work is a unique "embedded" case study, in an interpretativist epistemological positioning and an abductive approach. It feeds on data from various sources; but, it is based mainly on semi-structured interviews. The research uses the Actor Network Theory (ANT) as a framework for observation and thematic analysis. The general result is that, the system is implemented but it lacks to convey organizational transformations and coexists with former manual practices. By discussion of these results, two original contributions are made concerning the factors that influence the effective realization of the objectives of organizational change related to ICT implementation in the African Customs. On the one hand, contrary to the national cultural differentiation perspective that is often used in similar work in the African context, the research points out the important role of organizational variables; namely, organizational cultural values. And, on the other hand, in line with its interpretativist positioning, the research underlines the way the process is managed as a determining factor for the results that come out. So, at the managerial level, research highlights the shortcomings of the “top-down” style of management. But above all, from this perspective, it proposes concrete ways of correcting these deficiencies through three recommendations: the application of a polyphonic management model (based on the principles of ANT); the reduction of cultural conflicts; and the rooting of managerial instrumentation in the cultural characteristics of the social environment. [less ▲]

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See detailL’INHIBITION DE LA MÉTHYLTRANSFÉRASE EZH2 DU COMPLEXE RÉPRESSEUR POLYCOMB FAVORISE LA RÉPONSE ANTI-TUMORALE DES MACROPHAGES M2 DIRIGÉE CONTRE LES CELLULES DU MÉSOTHÉLIOME PLEURAL MALIN
Hamaïdia, Malik ULg

Doctoral thesis (2017)

Context: Malignant pleural mesothelioma (MPM) is an aggressive neoplasm affecting mesothelial cells from the pleura, pericardium and peritoneum. The disease is closely associated to asbestos exposure ... [more ▼]

Context: Malignant pleural mesothelioma (MPM) is an aggressive neoplasm affecting mesothelial cells from the pleura, pericardium and peritoneum. The disease is closely associated to asbestos exposure. Despite of rules to reduce workplace exposure to asbestos, incidence of mesothelioma is predicted to increase until 2020. Since MPM is resistant to conventional cancer therapies such as surgery, irradiation and chemotherapy, development of new options is urgently needed. In my project, I investigate the ability of immunotherapy to improve patients' outcome. My hypothesis postulates that tumor cells are tightly controlled by the immune system. In fact, clinical evidence indicates that tumor infiltration by tumor associated macrophages (TAMs) correlates with poor prognosis in malignant mesothelioma (MM). By attenuating the immune response, TAMs indeed promote survival of MM cells. TAMs share properties with alternative macrophages (M2) and are activated by anti-inflammatory (e.g. IL-10) or Th2-associated (i.e. IL-4, IL-13) cytokines. In contrast, classical (M1) macrophages are stimulated by interferon (IFN)-γ and microbial components (e.g. LPS). Aim: We hypothesized that macrophage activation is mediated by a transcriptional program tightly regulated by epigenetic modifications. We focused on the Polycomb Repressive Complex 2 (PRC2) EZH2 lysine methyltransferase responsible for trimethylation of histone H3 at lysine 27 (H3K27me3). Results: Our data show that inhibition of EZH2 reduces phagocytic activity by M2-polarised macrophages. Moreover, the cytotoxicity of supernatants conditioned by M2-macrophages is increased in presence of the EZH2 inhibitor. Finally, inhibition of EZH2 enhances the tumoricidal potential of M2 macrophages towards MM cells. We further demonstrate that macrophage killing activity requires superoxide radicals (O2.-) and peroxynitrites (ONOO-) derivatives produced by the NADPH oxidase system. Conclusion: EzH2 inhibition implements the tumoricidal potential of macrophages and may therefore improve the efficacy of immunotherapy of MM patients. [less ▲]

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See detailClimate change and insect pests: Impact on carbon dioxide increase on aphid behavior and semiochemistry
Boullis, Antoine ULg

Doctoral thesis (2017)

There is no longer any doubt on the incidence of rising carbon dioxide (CO2) concentration on global change. Climate modifications are responsible of perturbations in interactions between living organisms ... [more ▼]

There is no longer any doubt on the incidence of rising carbon dioxide (CO2) concentration on global change. Climate modifications are responsible of perturbations in interactions between living organisms. This research topic is in the light of scientists since several decades and is considered to be of major interest in the understanding of future ecosystems’ functioning. In this prospect, interactions between insect herbivores and their natural enemies have received little attention under a climate change scope, while they are of paramount importance in the proper equilibrium of agro-ecosystems. As the efficacy of natural enemies is governed largely by behavioral mechanisms, changes in the predators’ behaviors but also in those related to prey defenses can change the dynamics of insect populations. As aphids are considered as one of the main crop pests in temperate regions, relative literature on impact of increases in atmospheric CO2 concentrations on aphid population dynamic now exists. However, few publications about their chemical ecology are reported. Aphids are using many chemical signals to communicate with each other or in their interactions with higher trophic levels. Here, I tempted to identify the impact of an increase in atmospheric CO2 concentration on the interactions between aphids and their natural enemies mediated by semiochemicals. Aspects of phytovirus transmission by aphids were also covered. After being involved in three literature reviews, I was interested in the aphid alarm signaling which strongly supports aphid-predators interactions. In the pea aphid Acyrthosiphon pisum (Harris), this signaling is mediated by a pheromone, namely the (E)-β-farnesene. For my experiments, I took into consideration the importance of all the steps that this molecule has to pass by, from its production into the emitter individual to the induced behavioral response of the receivers. The results obtained during these experiments highlighted an imbalance in aphid chemical communication for populations grown under elevated CO2 conditions, by modifications in several steps of the signal (decrease in pheromone production, emission and associated behavior). The results obtained here were supported by previous studies indicating that increases in CO2 concentration reduce the aphid escape behavior, which makes them potentially more susceptible to predation. We know that many plant pathogens are dependent on aphid dispersal to spread, so it is of major importance to predict how these insect vectors could be affected by forecasted climate. I thus carried my interest on the ability of aphids to transmit phytoviruses under changing atmosphere. Using another aphid model, the green peach aphid Myzus persicae (Sulzer), we have not observed any modifications in terms of virus and aphid spread in laboratory trials when tested under either actual or forecasted CO2 concentration. However, the viral transmission efficiency via aphids is increased under CO2-enriched atmosphere. Finally, the host searching behavior of an aphid predator was studied. The efficiency of natural enemies of insect pests is mainly driven by their ability to find food sources or oviposition sites in their environment. The conducted study highlighted the preference of the hoverfly Episyrphus balteatus De Geer towards aphid colonies grown under actual CO2 levels, suggesting modifications in chemical cues guiding hoverflies to a suitable oviposition site, due to increase of CO2. The results and knowledge obtained during these studies will add novel information on how a major component of climate change may impact tritrophic interactions and thus the efficiency of natural enemies of insect herbivores in biological control scope. [less ▲]

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See detailCaractérisation et élaboration d'un outil de surveillance des cuvettes oasiennes et de leurs alentours par télédétection et système d'information
Karimou Barké, Mahamadou Salifou ULg

Doctoral thesis (2017)

Situées en zone semi-aride, les cuvettes oasiennes du centre-est du Niger sont des agro-écosystèmes à hautes potentialités. C’est seulement à l’intérieur de ces dernières que l’agriculture est possible ... [more ▼]

Situées en zone semi-aride, les cuvettes oasiennes du centre-est du Niger sont des agro-écosystèmes à hautes potentialités. C’est seulement à l’intérieur de ces dernières que l’agriculture est possible durant toute l’année. Ces cuvettes oasiennes ont connu de nombreux investissements de la part de plusieurs ONGs et projets au cours des dernières années. Cependant, elles sont souvent peu connues par ces acteurs du développement du fait de leur grand nombre et de leur extrême diversité. Cette thèse cherche à réduire cette méconnaissance à travers les activités suivantes: • évaluer les performances de trois méthodes de classification d’images appliquées à la détection de ces cuvettes oasiennes dans le Département de Gouré. Ces méthodes sont l’analyse pixellaire, l’analyse texturale et l’analyse par objet. Elles sont appliquées à des images SPOT 5-THX de 2.5 m de résolution ; • caractériser la forme des cuvettes oasiennes avec deux indices morphologiques (l’indice de compacité de Gravelius et l’indice fractale de leurs contours) ainsi que leurs orientations en utilisant les secteurs de la rose de vent comme repères ; • évaluer les contraintes et potentialités liées aux unités de paysage des cuvettes et de leurs alentours pour l’ensemble des cuvettes oasiennes à partir des extensions de ces unités de paysage, élaborer des indicateurs spatiaux de caractérisation des cuvettes ; • analyser la dynamique de l’occupation des sols de cuvettes oasiennes et de leurs alentours en utilisant les images Landsat 5-TM de 1984, les images SPOT 3 de 1996 et les images SPOT 5-THX de 2013. • proposer un outil de monitoring et une esquisse de système expert orienté à partir des données récoltées par ce biais sur l’ensemble des cuvettes de la zone d’étude. L’évaluation des résultats montre que l’approche par objet (précision globale égale à 97.12%, coefficient Kappa égal à 0.97) est plus performante que celles utilisant la texture (précision globale égale à 89.61%, coefficient Kappa égal à 0,90) et l’analyse par pixel (précision globale égale à 80.58 %, coefficient Kappa égal à 0.80). Une première information originale, à savoir le nombre, la position et la surface de l’ensemble des cuvettes sur la zone d’étude est fournie. Le nombre total de cuvettes oasiennes dans le Département de Gouré est ainsi estimé à 10717. Cet inventaire de ces lieux stocks de ressources est une première étape obligatoire pour leur caractérisation morphologique et pour l’évaluation de leurs potentialités agricoles. L’indice de forme de Gravelius met en évidence une certaine diversité de leurs contours : des cuvettes circulaires (9%), ovales (47%), amiboïdes (11%), étirées (18%) et très étirées ou étirées-amiboïdes (16%). La dimension fractale permet de distinguer trois classes de cuvette selon le degré de lissage de ces contours : très lissées (39%), lissées (50%) et moyennement lissées (10%). Le lissage est interprété ici comme un indicateur d’éolisation des pourtours des cuvettes. Enfin la détermination de l’orientation des grands axes des cuvettes a permis d’identifier quatre secteurs majeurs : E-W (23%), N-S (21%), NE-SW (22%) et SE-NW (34%). Ces analyses morphologiques et d’orientation appliquées pour la première fois à l’ensemble des cuvettes oasiennes du Département de Gouré offrent des éléments permettant de comprendre les processus d’ensablement des cuvettes oasiennes dans cette zone. L’analyse des indicateurs des potentialités naturelles à la mise en valeur agricole montre que les cuvettes oasiennes sont des espaces multi-usages, avec des aptitudes en arboriculture, maraîchage, en natron et en foresterie selon les unités géomorphologiques. Le pourcentage des surfaces cultivables est faible pour 45.8% des cuvettes et fort à très fort pour seulement 3.9 %. Celui des surfaces boisées est très fort sur 61.6 % des cuvettes soit 51.4 % en superficie. Les cuvettes possédant un sol nu à natron et/ou une nappe d’eau affleurante représentent 17.6 % des cuvettes. Quant aux indicateurs de risque de dégradation, ils montrent que 3.3 % et 0.5 % des cuvettes ont respectivement une menace d’ensablement fort et très fort à moyen terme. Alors qu’à terme immédiat, c’est respectivement 3% et 0.8 % des cuvettes dont la menace d’ensablement est fort et très fort. Concernant l’évolution récente de ces milieux, les superficies des cuvettes oasiennes ont régressé de 46783 ha en 1984, à 40831 ha en 1996 et 34553 ha en 2013. Inversement, leur nombre a augmenté de 1984 (8911) à 2013 (10717). Ceci s’explique certes pour partie par les résolutions différentes des images satellitaires utilisées, mais surtout par la fragmentation de certaines cuvettes du fait de leur dégradation et la création de nouvelles cuvettes par l’érosion éolienne. Cette dynamique est accentuée par celle de l’occupation humaine des paysages. Les abords des cuvettes et des vallées sèches constitués souvent d’édifices dunaires sont de plus en plus occupés par les cultures pluviales qui les exposent davantage à l’érosion. En 1984, les édifices dunaires et vallées sèches à culture pluviale représentent 295697 ha alors, qu’en 1996 et 2013, elles occupent respectivement 368153 ha et 423876 ha. Les systèmes d’information à référence spatiale esquissés permettent d’observer et de suivre la totalité des cuvettes oasiennes. Ce système, conçu en utilisant le langage UML, a permis non seulement d’établir des relations entre les indicateurs de potentiel valorisable et de dégradation mais aussi des informations supplémentaires récoltées sur le terrain (village, marché, zone de fixation biologique et mécanique des dunes). Ils offrent un accès aisé à ces indicateurs grâce à une interface informatique. À travers des requêtes sur cette base de données, les cuvettes à menace très forte nécessitant une intervention urgente pour leur conservation ont été mises en évidence ainsi que les variables explicatives du niveau d’exploitation des cuvettes. [less ▲]

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See detailUtilisation du D-galactose et du D-tagatose chez Bacillus sp.: Etude des protéines GalM et PBP4a de B. subtilis et B. amyloliquefaciens et Etude de la voie catabolique PTS-dépendante du D-tagatose chez B. licheniformis.
Van der Heiden, Edwige ULg

Doctoral thesis (2017)

Cette thèse s’intéresse à la métabolisation de deux sources de carbones, le galactose et le tagatose, dans des souches du genre Bacillus. La première partie de la thèse vise à montrer le rôle de GalM, une ... [more ▼]

Cette thèse s’intéresse à la métabolisation de deux sources de carbones, le galactose et le tagatose, dans des souches du genre Bacillus. La première partie de la thèse vise à montrer le rôle de GalM, une galactose mutarotase, dans la métabolisation du galactose chez B. subtilis ATCC 21332 et B. amyloliquefaciens FZB42. Le gène galM est organisé en opéron avec le gène dacC qui code pour un PBP de faible poids moléculaire, le PBP4a. Des mutants ponctuels et de délétion ont été générés dans le but d’étudier l’implication des produits de cet opéron dans la formation de biofilms in vitro, dans le remodelage de la paroi bactérienne et dans la colonisation de racines de plantes (plants de tomate et Arabidopsis thaliana). Une différence significative de colonisation a été mise en évidence entre la souche sauvage de B. amyloliquefaciens FZB42 et son double mutant uniquement sur les racines de plants de tomate. Toutefois, il pourrait s’agir d’un effet indirect lié à la méthode. Après analyse des muropeptides composant le peptidoglycane isolé en phase végétative, aucun rôle in vivo n’a pu être attribué au PBP4a. Cependant, l’attachement de cette protéine à la membrane de la bactérie a pu être mis en évidence. Une couronne de charges positives en surface du domaine II du PBP4a est responsable de cette localisation. La seconde partie de la thèse présente la voie de métabolisation du tagatose découverte chez B. licheniformis. Cette source de carbone est transportée et phosphorylée par les composants du système phosphotransférase (PTS) : EIIAT AG (TagM) et EIIBCT AG (TagL). La fonctionnalité du cluster de gènes identifié dans le génome de la bactérie a été démontrée par des expériences de supplémentation dans deux souches initialement incapables de métaboliser cette source de carbone : B. subtilis et E. coli. Le tagatose est phosphorylé durant son transport au niveau du carbone C1. Le tagatose-1-phosphate, présent principalement sous la forme -pyranose, est ensuite phosphorylé par l’enzyme TagK, une tagatose-1-phosphate kinase. Les paramètres cinétiques de l’enzyme ont été déterminés et la spécificité en faveur du tagatose-1-phosphate a été démontrée. Le tagatose 1,6-bisphosphate généré par TagK est hydrolysé en DHAP et G3P par GatY, une tagatose 1,6-bisphosphate aldolase de classe II. [less ▲]

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See detailCattle grazing dynamics under contrasted pasture characteristics at temporal and spatial scales
Andriamandroso, Andriamasinoro ULg

Doctoral thesis (2017)

Grassland constitutes an important and a low-cost food source for grazing livestock. Optimal management should consider both forage resource productivity and animal needs. For cattle, grazing is a normal ... [more ▼]

Grassland constitutes an important and a low-cost food source for grazing livestock. Optimal management should consider both forage resource productivity and animal needs. For cattle, grazing is a normal behavior displayed in an attempt to eat the amount of forage to fulfill their nutritive requirements for maintenance and production. It is the most time-consumed activity of cows reared in pasture-based systems. With the increase of herd size, on one hand, farmers have been constrained to integrate innovative tools and techniques, such as milking robot, to improve the production system in particular to reduce the labor cost. On the other hand, such change might reduce time allocated for grazing on pasture. However pasture-based systems constitute a real pillar for sustainability as they are socially acceptable and environmentally profitable as they play an important role on ecosystem services and biodiversity provision. Studying grazing processes at individual level, which finally is the key point of animal-plant interactions, is a valuable research domain to enhance the knowledge about this mechanism and to feed decision support tools. This thesis aimed to link the changes in pasture characteristics to the grazing behavior of cattle in order to better understand the grazing strategy under different pasture characteristics and forage allowances. To allow an individual monitoring, sensor technology has integrated within farms and livestock researches to monitor many physical variables, inducing the emergence of precision livestock farming approach. Different types of sensors were designed, and already commercialized for some, primarily for physiological status detections such as heat, parturition or diseases. Grazing behaviors could be monitored using pressure, electromyography, acoustic or accelerometric sensors by classifying posture and movements of the animal into unitary behaviors (grazing, ruminating, resting, walking, etc.) and finer behavior such as chews and bites through jaw movements’ detection. When compared to real observation, detection accuracies of these behaviors were variable according to the type of sensor, its position on the animal during data acquisition on pasture, the data recording frequency, the time-window and the method dedicated to the post-recording data analysis. State-of-the-art analysis demonstrated a great performance of accelerometers for unitary behaviors and bites detection. An inertial measurement unit, integrating accelerometer, gyroscope and location sensors, was used for recording cattle movements during grazing at high sampling rate (100Hz). It allows a correct detection of grass intake and rumination behaviors with an average accuracy of 91% using 1-second time-window when calibrating and validating the detection algorithm. Deeper analysis of accelerometric signal allowed us to detect bites and chews performed during grazing and ruminating. Effects of pasture heights on grazing bites characteristics were differentiated by a higher frequency when pasture is at a lower height. Finally when combined to geographical information, a similar pattern was observed for cattle grazing on the same spot confirming their herd movement during grazing in terms of bites location. Differences were visible under different pasture heights but not significant. Such bites location, combined with continuous monitoring of cattle behaviors, through use of sensors, should be furtherly linked with more pasture characteristics, if possible with the same accuracy, and monitored on longer period in order to obtain a complete coverage of cattle grazing strategy and the effect of contrasted environment in order to purpose valuable tool for a better grazing management. [less ▲]

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See detailImprovement of genetic evaluation systems for maternally influenced traits and multi-breed livestock populations
Vanderick, Sylvie ULg

Doctoral thesis (2017)

Animal breeding programs are designed to genetically improve livestock populations over many generations to enhance farm sustainability and competitiveness. Genetic improvement is achieved by selecting ... [more ▼]

Animal breeding programs are designed to genetically improve livestock populations over many generations to enhance farm sustainability and competitiveness. Genetic improvement is achieved by selecting genetically superior animals, based on estimated breeding values, to be the parents of the next generation. These estimated breeding values are calculated by solving mixed model equations characterizing appropriate statistical genetic evaluation models. To guarantee effective genetic selection, genetic evaluation models must be tailored to the specific characteristics of the traits and population under evaluation. This PhD thesis focused on the development of genetic evaluation models suitable for categorical maternally influenced traits and for multi-breed populations. Appropriate genetic animal models were developed and assessed: (1) for two categorical maternally influenced traits based on calving ease scores from Walloon Holstein dairy cattle and on lamb survival data from a New Zealand sheep population; (2) for two multi-breed populations based on milk yield records of New Zealand purebred and crossbred dairy cattle, and on purebred and crossbred calving ease scores from Walloon Belgian Blue and Holstein cattle. Results showed that (1) fitting maternal effects was required to avoid biasing the estimated breeding values, and there was no clear advantage in using non-linear mixed models instead of linear mixed models for the genetic analysis of the two categorical maternal traits studied; (2) breed-dependent breeding values could be estimated using the proposed multi-breed models, and that combining purebred and crossbred data had a positive influence on the accuracy of the breeding values of purebred animals. Finally, part of the research presented in this thesis contributed to the development of the genetic evaluation systems currently used in Walloon Region of Belgium and in New Zealand. [less ▲]

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See detailAnalyse Économique des Échanges Intra et Extracommunautaires de l'Union Économique et Monétaire Ouest-Africaine
Soma, Sassiémiké Abdoul Kader ULg

Doctoral thesis (2017)

Résumé de la thèse Le passage de l’Union Économique et Monétaire Ouest-Africaine (UEMOA) à une union douanière en janvier 2000 témoigne de la volonté des pays membres à promouvoir et à intensifier les ... [more ▼]

Résumé de la thèse Le passage de l’Union Économique et Monétaire Ouest-Africaine (UEMOA) à une union douanière en janvier 2000 témoigne de la volonté des pays membres à promouvoir et à intensifier les échanges commerciaux au sein de la zone. Plus de 15 ans après la création de ce vaste marché, les chiffres du commerce intra-communautaire ne sont guère encourageants. En effet, le ratio d’échanges intra-UEMOA stagne autour de 12%, nettement en dessous de ses échanges avec ses partenaires de l’UE et des 7 autres pays de la CEDEAO. La présente thèse a d’abord investigué le poids des barrières dans les échanges intra-UEMOA relativement à celles dans les échanges avec l’Europe et les autres pays de la CEDEAO. Les résultats montrent l’existence de plus de barrières dans les échanges avec l’UE et la CEDEAO que dans les échanges intra-UEMOA. Mieux, la faiblesse des échanges intra-communautaires doit être résorbée moins par la réduction des barrières dans les échanges mutuels que l’amélioration des facteurs d’offre et de demande. Ensuite, nous avons montré que la faiblesse des échanges intra-UEMOA est liée à leur mauvaise structure. En effet, les résultats montrent que les flux croisés de biens similaires entre pays de l’UEMOA sont faibles et leur augmentation permettrait non seulement de stimuler les échanges intra-communautaires, mais également de créer un effet multiplicateur du commerce sur la croissance. Enfin, après avoir analysé la dynamique de la croissance, du commerce et des investissements directs étrangers dans l’UEMOA, nous montrons que s’il existe une dynamique positive de long terme entre la croissance et le commerce, les IDE sont par contre défavorables à la croissance de long terme. Les recommandations vont dans le sens d’orienter davantage les IDE vers les secteurs de transformations capables de générer plus de productivité à long terme. [less ▲]

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See detailContribution à la mise en place d’une plateforme de transgénèse chez la volaille domestique: culture, cryopréservation et ingénierie génétique de cellules germinales primordiales.
Tonus, Céline ULg

Doctoral thesis (2017)

Primordial germ cells (PGCs) are the intermediate of choice for domestic fowl transgenesis and genome editing. These can support large transgenes insertions and, as precursors of the germline, can ... [more ▼]

Primordial germ cells (PGCs) are the intermediate of choice for domestic fowl transgenesis and genome editing. These can support large transgenes insertions and, as precursors of the germline, can transmit a genetic modification to the next generation. Moreover, given the difficulties for cryopreserving avian gametes (spermatozoa and, above all, oocytes), PGCs represent the material of choice for germplasm preservation in these species. Despite the obvious advantages of PGCs use, recently described related technologies appear generally as more difficult to pursue, and as less effective than expected. In this context, we have developed and optimized some of them which appear as essential for carrying complex chicken genome engineering projects. We first focused on improving the effectiveness of culture and cryopreservation of PGCs. By developing a culture method in inserts, ending up with an efficiency close to 40 %, we were able to isolate and long-term cultivate chickens PGCs from 3 commercial breeds and 2 Belgian endangered local breeds. The cells showed all the characteristics of the PGCs in terms of morphology, markers' expression and gonadal migration. We also applied a cryopreservative vitrification method, which showed results superior to those obtained by conventional slow freezing. During the last part of this work, we genetically engineered PGCs to obtain stable transfectants expressing GFP. These transfectants allowed us to examine long-term gonadal colonization and germline transgene transmission. We also tested a Cre recombinase-mediated site-specific cassette exchange method. As a final result, we have developed the methods and know-how mandatory to allow efficient harvesting, expansion, genetic engineering, reimplantation and cryopreservation of chicken PGCs, and we have shown the possibility of germline transmission of a long term cultured and genetically modified PGCs line. [less ▲]

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See detailImpact de l'influence sociale de l'équipe dirigeante sur la culture de responsabilité des médecins dans les Centres Hospitaliers Universitaires Algériens
Bounazef, Djida ULg

Doctoral thesis (2017)

This research analyses the impact of leaders’ social influence on physicians’ culture of accountability through the study of organisational values and practices in hospitals. It analyses the impact of ... [more ▼]

This research analyses the impact of leaders’ social influence on physicians’ culture of accountability through the study of organisational values and practices in hospitals. It analyses the impact of social identity, values normalisation, conformism, practices of post-new public management and quality of interactional climate on the sensitization of social values, behaviours and actions. The research model refers to the works of Tajfel/Turner, Lewin and Schein/Hofstede. It analyses strength of hospital culture, existence of sub-cultures, importance of informal authority and power pressures’ perception between leaders and physicians. Results highlight strength of social values, level of attachment, culture of accountability’s perception and strength of motivation to shared accountability’s factors of 380 physicians in 5 different University Hospitals. [less ▲]

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See detailUse of end-of-waste foamed fibers and aggregates into a cementitious mortar
Coppola, Bartolomeo ULg

Doctoral thesis (2017)

Durability and sustainability of cementitious materials are two important issues in the field of construction materials. Durability is defined as the ability of cementitious materials to resist weathering ... [more ▼]

Durability and sustainability of cementitious materials are two important issues in the field of construction materials. Durability is defined as the ability of cementitious materials to resist weathering action, chemical attack, abrasion or any other process of deterioration. The use of fibers is a viable solution to partially overcome the brittle behavior of such materials. At the same time it is demonstrated that fibers, by reducing cracking phenomena, allow to face the durability related issues. Different fibers have been used according to the aims of composite materials: high strength fibers are generally used for structural purposes (toughness increase) while low modulus synthetic fibers are mainly used to avoid plastic shrinkage cracking. The effectiveness of fibers reinforcing action lies mainly on the fiber/matrix interactions. Three types of interactions can be recognized: i) physical and/or chemical adhesion; ii) friction and iii) mechanical anchorage induced by deformations on the fiber surface (e.g. crimps, hooks, twisted or deformed fibers in general). Sustainability can be identified according to the definition of sustainable development stated in 1987 by Brundtland et al.: “the development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. Sustainable development should take into account economic growth, social equality and environmental protection. The construction industry involves all these fields: the main concerns are raw materials consumption and CO2 emissions during cement production. Moreover, also the plastic production and disposal present several environmental issues. Once again, raw materials consumption and the speed with which these materials became waste. Thus, seen the aforementioned drawbacks related to cementitious materials, this Ph.D. was aimed to study the possibility of using end-ofwaste materials (i.e when waste ceases to be waste and becomes a secondary raw material) for the production of synthetic fibers and aggregates characterized by improved mechanical interactions with the cementitious matrix. To this extent, fibers and aggregates with a rough and porous surface, able to offer interlocking positions for the cementitious matrix, were produced in laboratory by melt extrusion-foaming process. Moreover, some chemical treatments (alkaline hydrolysis and sol-gel deposition of nanosilica) were performed on fibers, to improve chemical adhesion with the cement paste. Finally, taking into account the need for reducing the consumption of raw materials, foamed fibers and aggregates were produced starting from a polymeric end-of-waste material made of a polyolefins blend (HDPE, LDPE and PP). Alkaline hydrolysis promoted the creation of interlocking positions on fiber surface but the best behavior was recognized for fibers with nano-silica particles on the surface. In this case, a denser ITZ and a great amount of hydration products were observed by SEM investigations. Pull-out tests confirmed the better performances of treated fibers: a higher pull-out peak load was achieved and an increase of pull-out energy was evident. Subsequently, a foam extrusion process was used to manufacture polymeric fibers (both virgin and recycled) with a rough surface, to improve mechanical friction with the cementitious matrix. Optimizing foaming agent quantity and processing parameters was possible to produce fibers having adequate surface texture and diameter to be used in fiber reinforced mortars. Although fiber reinforced mortars workability decreases at increasing fiber volume fraction, the results demonstrated that this happens to a lower extent for mortars containing foamed fibers. Fibers mechanical properties decreased at increasing fibers porosity but fiber reinforced mortars mechanical properties, flexural and compressive strength, were not influenced by fibers addition nor their morphology. The rougher surface gives rise to a better fiber/matrix adhesion, as confirmed by pull-out tests. Durability investigations on the fiber reinforced mortars reported good results for capillary water absorption, sulfate attack and plastic shrinkage cracking. In particular, fibers length and volume fraction are key parameters in controlling plastic shrinkage cracking. Moreover, mortar samples containing foamed fibers displayed a better control of shrinkage cracking: cracks opening was delayed and the improved fiber/matrix bond was able to reduce crack width, compared to mortars containing smooth fibers. Finally, lightweight artificial aggregates (LWAs) were produced, starting from foamed strands. At increasing LWAs substitution, a sharp decrease of density was achieved. Also workability and mechanical properties decreased, but a more ductile behaviour was recognizable. Thermal conductivity and water vapor resistance were proportional to mortars density which obviously decreased at increasing natural sand substitutions. Moreover, the use of aggregates porosity as reservoir of internal curing water showed promising preliminary results. In brief, the results of this study demonstrate that engineered fibers with improved fiber/matrix bond allow to optimize (i.e. to reduce) fibers volume fraction in cementitious mortars. Foamed fibers characteristics can be in turn optimized by changing the manufacturing process conditions. Benefits could be not only in the control of plastic shrinkage cracking but also in the workability of fresh mortars, mechanical strength and durability of the hardened composite. In addition, using end-of-waste materials a more sustainable product can be obtained. In particular, replacing natural aggregates with plastic aggregates, is possible to reduce raw materials consumption and improve mortar properties (mainly unit weight, thermal conductivity and water vapor permeability). [less ▲]

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See detailDiscrimination of mercury contamination sources and pathways using Hg stable isotopes in the European seabass, Dicentrarchus labrax
Cransveld, Alice ULg

Doctoral thesis (2017)

Mercury (Hg) is a persistent toxic compound whose amount in the global biosphere has at least tripled since industrialization. The biogeochemical cycle of mercury is particularly complex because elemental ... [more ▼]

Mercury (Hg) is a persistent toxic compound whose amount in the global biosphere has at least tripled since industrialization. The biogeochemical cycle of mercury is particularly complex because elemental mercury is very volatile, has a long residence time in the atmosphere and thus can potentially reach locations that are very distant from the initial emission source. Since the 70’s, many international organisations (OECD, EU, UNEP) have implemented different policies to reduce Hg pollution. However, for these policies to be efficient, the polluters/Hg sources have to be fully assessed and identified. So, there is a crucial need to trace Hg sources and to assess the quantitative impact of local versus global Hg sources on ecosystems. Recently, the study of the seven Hg stable isotopes has emerged as a new promising technique affording to explore the Hg cycle both in situ and in laboratory. Mercury stable isotopes display both mass dependent fractionation (MDF, reported as δ202Hg) and mass independent fractionation (MIF, reported as Δ199Hg and Δ201Hg). The combination of both values should allow to trace back sources and pathways of Hg and methylmercury (MeHg). But, so far, few studies have considered Hg isotopes in marine vertebrates. Thus, the general objective of this thesis was to study a marine predator, the European seabass, Dicentrarchus labrax, to explore the possibility of using mercury stable isotopes to investigate Hg sources and pathways in European coastal waters. Our specific objectives were to characterize the Hg profile (THg, MeHg and isotopy) of wild populations of seabass, to assess whether Hg isotopes differed between populations and could give indications on Hg sources, with special attention paid to differentiate local versus global Hg sources. We also wanted to explore internal variation of Hg profiles by comparing several tissues. And, we wanted to validate our interpretations of in situ results by experimentally evaluating the potential fractionation between muscle and liver tissues of D. labrax, and between the diet and fish tissues. To fulfill our objectives, we split the thesis in 3 axes. First, juvenile seabass were collected in seven geographically distinct locations: the Agiasma lagoon in the northern Aegean Sea (AeS), the North Sea (NS) along Belgian and English coasts, the Seine estuary (SE), the Turkish coast of the Black Sea (BS), the Marano and Grado lagoons in the northern Adriatic Sea (NAS), the Portuguese lagoon, Ria de Aveiro, at two distinct sites: a very contaminated one (RAC) and a least contaminated one (RAR). v Our results showed seabass displayed extremely variable THg (Total mercury) concentrations amongst locations. Environmental contamination of the fish habitats seemed to be the main driving factor of THg concentrations in their tissues. Then, we showed that the populations also had distinct Hg isotopic niches (using SIBER on Hg stable isotopes, a premiere!), and that Hg isotopes (Δ199Hg and δ202Hg) could be used as a discriminating tool. We showed that Hg isotopes also told more about the origin of THg contaminating juvenile seabass: Δ199Hg values indicated a rather coastal MeHg source while δ202Hg could be linked with the global versus local Hg origin. Some populations like AeS were thought to be affected mainly by background, global Hg source, while other sites such as RAC (and SE and NAS) that were more heavily contaminated, would undergo a strong influence of local contamination. The previous observations were made in muscle tissue. Since different tissues often have distinct turnover times and different affinity for pollutants, the second axis of this thesis aimed at comparing liver and muscle results. So, we investigated the liver tissue of the very same individuals than in axis 1. The THg RATIO (THgliver/THgmuscle) was very variable amongst populations. We found that Hg organotropism (affinity for different organs) was influenced by the overall contamination level and maybe also by the food regime (via the %MeHg in diet). The Hg isotope composition also differed between muscle and liver of wild seabass. Hg speciation was most probably not the only cause of such a difference, and there was certainly an internal fractionating process (MDF). We even found serious indication of mercury demethylation happening in seabass, although demethylation in fish had yet to be proven. This is what our 3rd axis addressed. We exposed captive juvenile seabass to environmentally relevant THg concentrations through the diet. Observations confirmed in situ results: Hg organotropism depends on the %MeHg in diet, and THg RATIOs < 1 are to be related to the extremely small proportion of inorganic Hg in the seabass diet. Most of all, we found strong and concordant indications of demethylation process occurring in seabass that would be responsible for the systematically distinct δ202Hg values observed between muscle and liver. In conclusion, our findings constitute the first large scale Hg stable isotope study, on a single fish species, from European coastal waters. They demonstrate the interest and relevance of using Hg stable isotopes to investigate the Hg cycle and sources on both small and large scales and show the possibility to differentiate between global and local Hg sources. This takes a crucial sense in the current context where tracing Hg contamination sources is necessary to implement efficient environmental policies. [less ▲]

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See detailModélisation spatiale de la production fourragère en zone pastorale nigérienne
Garba, Issa ULg

Doctoral thesis (2017)

This work was carried out on the pastoral zone of Niger, the main objective was to contribute to the improvement of the methods of forage yields predicting mainly in the Sahel and especially in Niger ... [more ▼]

This work was carried out on the pastoral zone of Niger, the main objective was to contribute to the improvement of the methods of forage yields predicting mainly in the Sahel and especially in Niger. This is specifically to validate the model BIOMASAH of ARC; test the MEIA model; to establish a reference model by multiple linear regression; test the similarity method and finally compare the methods. The work was carried out on the one hand with the data measured on the ground by the MEIA from 2001 to 2012, reel rainfall of Niger observations network, meteorological parameters from ECMWF and also with satellite images as SPOT NDVI VEGETATION and MODIS, RFE2 of FEWS NET. Validation of BIOMASAH model was made by t and Wilcoxon tests to compare reel biomass and outputs of the model. Pearson, Kendall and Spearman correlation testing was also made. The MEIA model performance was tested by confronting the results between and within SPOT VEGETATION and MODIS sensors, by comparing R² and RMSE from the integral and maximum NDVI as a predictor of forage yield. Average comparisons by parametric and nonparametric tests were also made to compare the results. The reference model (RM) was produced by multiple linear regression with stepwise method. The selection of variables was based on adjusted R² and RMSE and the LOOCV leave one out cross validation to calculate R² for validation, we made also systematic diagnosis of residues for better characterization of the model. The similarity method was performed using the R², MAD and RMSE as a criterion, the profile of the vegetation growth period of each pixel was plotted for all years. Then we compare the profile of the target year with those of other years to identify the similar year. One hand the results of similarity were compared with actual data with the Pearson correlation test, Spearman and Kendall and secondly using t and Wilcoxon tests to compare means. Comparison of models was made on the basis of R², Adjusted R² and RMSE. Model BIOMASAH result on significant difference between average (p <0.001). Pearson correlations, Kendall and Spearman are low. Regarding the MEIA model, globally R² (0.56) is best, there’s no difference to use MODIS NDVI or SPOT vegetation, the RMSE is 367 kg.ha-1. R² and RMSE vary greatly from one year to another. On a global scale the multiple linear model gave a good R² adjusted (0.69) and RMSE (282 kg / ha) the difference between the calculated and the RMSE of validation is 2.72 kg. Comparing averages of the similarity to the real ones showed that there are no significant differences (p <0.001) for R² with the differences are significant against the same threshold for the MAD and RMSE. The Comparison of the models shows that the multiple linear regression one (reference model) is the best. Research should continue with index like LAI, FARAR and EVI. [less ▲]

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See detailGénération d’une librairie de mutants de Bacillus licheniformis 749/I par l’insertion aléatoire d’un transposon pour identifier les gènes impliqués dans l’induction de la β-lactamase BlaP
Lebrun, Sarah ULg

Doctoral thesis (2017)

La production de la b-lactamase BlaP chez Bacillus licheniformis 749/I est induite par la présence d’un antibiotique à noyau b-lactame (b-lactamine) dans le milieu extérieur. Le récepteur membranaire ... [more ▼]

La production de la b-lactamase BlaP chez Bacillus licheniformis 749/I est induite par la présence d’un antibiotique à noyau b-lactame (b-lactamine) dans le milieu extérieur. Le récepteur membranaire BlaR1 détecte la présence de la b-lactamine et transmet un signal vers le cytoplasme. La protéine BlaR1 est composée de deux domaines : le domaine C-terminal (BlaR-CTD) exposé à l’extérieur de la cellule qui détecte la présence de l’antibiotique et le domaine N-terminal membranaire (BlaR-NTD) agissant comme un transducteur et un amplificateur du signal perçu par le domaine senseur. En présence de b-lactamine, l’acylation de BlaR-CTD par l’antibiotique entraîne un changement conformationnel des segments transmembranaires menant à l’activation de la boucle L3 de BlaR-NTD. Le répresseur BlaI, qui réprime la transcription du gène blaP, est inactivé par liaison d’un coactivateur, le dipeptide D-Glu--mA2pm issu de la dégradation du peptidoglycane à l’extérieur de la cellule. La voie d’entrée de ce dipeptide n’est pas connue ainsi que le locus blaR2 impliqué dans l’induction de la b-lactamase. L’objectif principal de ce travail est l’identification du locus blaR2 par la construction d’une banque aléatoire de mutants par transposition. La première étape du travail était la mise au point de la transformation de Bacillus licheniformis 749/I par un plasmide possédant une origine thermosensible et porteur d’un transposon modifié. Un clone recombinant a été obtenu par la méthode de transformation de protoplastes avec de l’ADN sous forme concatémère. Une banque d’environ 11.300 clones a été générée et validée. Une méthode de criblage sur boite via un test iodométrique a mis en évidence cinq mutants sur l’entièreté de la banque présentant une différence d’induction par rapport à la souche sauvage. L’identification des insertions chromosomique du transposon a été réalisée par PCR inverse et par AP-PCR et a permis d’identifier trois clones insérés dans le gène blaR1 et deux dans le gène blaP. Ces mutants sont tous différents entre eux. Une seconde stratégie a été envisagée en vue d’identifier le locus blaR2 par complémentation du mutant chimique blaR2- par l’ADN génomique isssus des mutants de la souche sauvage générés à partir du transposon. La souche blaR2- a été transformée cependant, aucun événement de recombinaison n’a pu être observé. Sur base de ces expériences, la question de l’identification du locus blaR2 reste en suspens. Néanmoins, au cours de l’isolement des clones contenant le transposon, nous avons mis en évidence des clones présentant des colonies possédant un phénotype « luisant » par rapport à l’aspect mat de la souche sauvage. Un gène codant pour une estérase (Bl-EstA) a été ainsi identifié et le produit du gène étudié. Bl-EstA appartient à la famille des lipases « hormone-sensitive lipase like_1 » (Famille IV de la classification d’Arpigny et Jaeger (1999)) et possède toutes les caractéristiques des a/b hydrolases. Bl-EstA est sous la forme dimérique en solution et peut adopter différents comportements cinétiques en fonction des substrats qu’elle hydrolyse : une cinétique Michaélienne classique, allostérique ainsi qu’une inhibition par le substrat. Ces comportements impliquent, au moins, la présence d’un site régulateur. Enfin, l’inactivation de Bl-EstA par les alcools n’est pas favorable à son utilisation pour des réactions de transestérifications et dès lors pour des applications industrielles. [less ▲]

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See detailDevelopment of Mass Spectrometry based Analytical Tools for Animal Venoms Characterization
Echterbille, Julien ULg

Doctoral thesis (2017)

Animal venoms and toxins are now recognized as major sources of bioactive molecules that may be tomorrow’s new drug leads. Their complexity and their potential as drug sources have been demonstrated by ... [more ▼]

Animal venoms and toxins are now recognized as major sources of bioactive molecules that may be tomorrow’s new drug leads. Their complexity and their potential as drug sources have been demonstrated by application of modern analytical technologies, which have revealed venoms to be vast peptide combinatorial libraries. Structural as well as pharmacological diversity is immense, and mass spectrometry is now one of the major investigative tools for the structural investigation of venom components. The present work is dedicated to the development of new mass spectrometry-based methodologies for the study of animal venoms. The first methodology depicts an original approach to sequence snake toxins in a higher throughput way after an orthogonal separation of the crude venom. The second analytical development is devoted to decipher disulfide connectivity in cone snails’ toxins through a combination of partial reduction/oxidation followed by ion mobility separation of the semi-reduced/oxidized species and CID fragmentation. The last part of this work is focused on the capture of ligands of nAChRs in complex mixtures of peptides, especially in cone snail venoms. A new ligand has been discovered and fully characterized. [less ▲]

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See detailGovernance of plant health and management of crop diversity - the case of common bean health management among members of the association Croqueurs de Carottes
Klaedtke, Stephanie ULg

Doctoral thesis (2017)

All over the globe, networks of seed growers are cultivating crop diversity in fields and gardens. Their contribution to the maintenance of this diversity has been studied, but research has widely left ... [more ▼]

All over the globe, networks of seed growers are cultivating crop diversity in fields and gardens. Their contribution to the maintenance of this diversity has been studied, but research has widely left aside their management of plant health. The governance of bean health practiced by an association of artisanal seed companies, Croqueurs de Carottes, is approached as a case study in the objective of specifying how management of crop diversity and governance of plant health are articulated. Their concern for the governance of bean health is elucidated from an agroecological perspective, taking an interdisciplinary and transformative approach. Actor-network theory constitutes the backbone of the thesis, situated between agronomy and sociology and drawing upon a threefold research device: on-farm experiments, semi-directive interviews and participant observation. The Croqueurs' approach to bean health is described as in situ approach, in which plant populations are considered healthy if they are able to live with potential plant pathogens and adapt to their growing environments. Relying on ecological interactions, competences of plant health management are distributed throughout the production system. Both for plant health and crop diversity management, a seed lot is determined by a complex system of interactions. A clear boundary distinguishing plant populations from their growing environment cannot be drawn. This implies (i) that plant health must be judged upon in situ in the plants' growing environment and (ii) that the governance of plant health must be considered at the collective scale. [less ▲]

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See detailMonitoring Lions (Panthera leo) using Digital 3D Models of their Tracks
Marchal, Antoine ULg

Doctoral thesis (2017)

As the Earth may be entering a new human-influenced geological time, the Anthropocene, the pressure on biodiversity due to increasing human populations and activities is unprecedented. Monitoring animal ... [more ▼]

As the Earth may be entering a new human-influenced geological time, the Anthropocene, the pressure on biodiversity due to increasing human populations and activities is unprecedented. Monitoring animal populations is essential to gain demographic data and assess their viability. Because of the difficulties linked to invasive methods that involve direct observation or handling, many researchers have explored alternative approaches such as using tracks. Tracks are the material by-product of the interaction between terrestrial animals and their physical environment due to gravity. The interpretation of tracks exists since the dawn of mankind and is a crucial factor for human evolution. As an integral part of hunting, the art of tracking involves cognitive thinking that may well be part of the origin of science. However, monitoring species through their tracks is controversial due to several reasons: unreliable recording techniques limited to two-dimensions, manipulator bias, substrate variation, misidentification of the foot from which each track originates, and subjective identification of the age, sex and/or individual. The aim of this thesis was to evaluate the possibility of monitoring lions Panthera leo through digital three-dimensional (3D) models of their tracks. The first step was to assess close-range digital photogrammetry as a low-cost, rapid, practical and reliable field technique for the digital 3D modelling of lion paws, tracks and trails. A trail, that is a continuous sequence of tracks made by the same individual, reflects the morphology and kinematics of that individual. The use of traditional morphometrics enabled the extraction of variables such as distances, angles and areas from the digital 3D trails originating from individuals of known age, sex and/or identity. When comparing adult lions walking at the same gait (i.e. same kinematics), the trail variables provided sufficient information to identify the sex and individual. The digital solution permitted the extraction of more variables than the usual pace, stride and straddle. These additional variables enabled a better discrimination between the sexes and individuals. As for the paw and track morphology, traditional morphometrics conveys limited information about the geometric structure, and fails to quantify the shape variations along curves and surfaces. To overcome these drawbacks, geometric morphometrics allowed the extraction of the form (i.e. size and shape) by means of superimposed fixed landmarks, and curve- and surface-slider semi-landmarks. Using fixed landmarks, the paws and tracks presented enough shape variation to identify their position along the anteroposterior (front or hind) and mediolateral (right or left) axes. We used fixed landmarks, with and without curve- and surface-sliders, on paws and tracks from lions of known age, sex and/or identity. The identification of the age and sex from the paws, and the age, sex and individual from the tracks achieved higher accuracies when using size and shape variables together rather than independently. The information from curves and surfaces offered an advantage for the identification from the tracks but not from the paws. Due to the variation in anatomy, paw morphology and individuality in walking, tracks and trails contain information about the individual lion that created them. Recent advances in digital close-range photogrammetry and geometric morphometrics allow the recording and extraction of that information, which can then provide data to help monitor lion populations using a non-invasive approach. [less ▲]

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See detailInactivation of DNA damage repair provides additional efficacy to the treatment of thyroid cancer
Neelature Sriramareddy, Sathyanarayana ULg

Doctoral thesis (2017)

Incidence of thyroid cancer has increased steadily over the last several decades. This type of neoplasm accounts for the majority of deaths due to endocrine cancers. The most frequent form, well ... [more ▼]

Incidence of thyroid cancer has increased steadily over the last several decades. This type of neoplasm accounts for the majority of deaths due to endocrine cancers. The most frequent form, well-differentiated thyroid cancer, is characterized by disease persistence, recurrence and a lack of response to radioiodine-131. With survival rates of 9 weeks to 5 months, anaplastic thyroid cancer has very poor prognosis. To provide additional efficacy to the treatment of thyroid cancer, we investigated the mechanisms of DNA damage and repair. We found that thyroid cancer cells undergo mitosis in presence of unrepaired DNA damage. To proliferate and survive, these cells repair DNA lesions very efficiently using homologous recombination (HR) and non-homologous end joining (NHEJ). Pharmacological inhibition of these pathways significantly increases apoptosis of thyroid cancer cells. This thesis thus demonstrates that targeting DNA damage repair pathways might have therapeutic value in relapsing and advanced thyroid cancers. [less ▲]

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See detailMusique et plaisanterie. Ethnographie de trois groupes sociaux (coolooji, ñeeñɓe et mbiruuji) à Djéwol (Mauritanie)
Sow, Aboubakry ULg

Doctoral thesis (2017)

The village of Djéwol (Mauritania) is located on the right bank of the Sénégal river and its' population is estimated to approximately 9000 inhabitants that are split to two communities, the Haalpulaar ... [more ▼]

The village of Djéwol (Mauritania) is located on the right bank of the Sénégal river and its' population is estimated to approximately 9000 inhabitants that are split to two communities, the Haalpulaar and the Soninké who are organinized into hierarchies. Straddling on both communities are the ñeeñɓe (social mediators) and the riimayɓe (servants), who are the main producers and actors of music. Although sometimes they declare themselves to be Haalpulaar, other times, they call themselves Soninké, mainly because of bilingualism and versatility of their music. For this reason, the ñeeñɓe and riimayɓe are conveyed to all manifestations and festivities that punctuate the life of the village. On such occasions, other genres of music are also played by coolooji (social protesters) and the mbiruuji (fighters), both of these being marginal subclasses who are constantly in conflict with the ñeeñɓe. Based on my position of researcher/musian/haalpulaar/dimo (noble) originating from this village and on my personal journey, while using a reflexive method, I will question the rôle and the place in the society of the three actors previously mentioned : The coolooji, the ñeeñɓe and the mbiruuji. Starting with an ethnological description and an anthropological analysis of the different operating modes of yano (pleasantry procedure) – which allow the denɗiraagal (similar to pleasantry) to be set into motion or not – in their articulation of music, it will be a matter of asking ourselves in which way the the coolooji, the ñeeñɓe and the mbiruuji define themselves and contribute to defining others through yano and music. Thus, the first part of this thesis suggests, beyond the presentation of the historical and social context of the community and Djéwol village, adopting a synoptic perspective on the Haalpulaar and Soninké music of the region near the Sénégal river. The second part, however, will focus on the origin of the different types of relations in jiidugal (kin) and of denɗiraagal (related of pleasantry) which proceed by using the yano, as well as the musical art associated with the later. Finally, the last part will be dedicated to analyzing the interactions, conflicting or not, as well as the absence of interactions between the coolooji, the ñeeñɓe and the mbiruuji while highlighting the similarities and the differences between these three significant figures. In conclusion, the situation will be analyzed in the light of the contemporary reconfigurations and of the evolution of the bounds tied between the denɗiraagal and the surrounding social networks. Le village de Djéwol (Mauritanie) se situe sur la rive droite du fleuve Sénégal et compte aujourd’hui 9000 habitants se répartissant en deux communautés, haalpulaar et soninké, fortement hiérarchisées en leur sein. À cheval sur les deux communautés, se trouvent les ñeeñɓe (médiateurs sociaux) et les riimayɓe (serviteurs) qui sont les principaux producteurs et acteurs de musique. Ceux-ci se déclarent tantôt haalpulaar tantôt soninké, notamment en raison de leur bilinguisme et de la polyvalence de leurs musiques. À ce titre, les ñeeñɓe et les riimayɓe sont conviés à toutes les manifestations et festivités qui rythment la vie du village. En ces occasions, d’autres genres de musiques sont également pratiqués par les coolooji (contestataires sociaux) et les mbiruuji (lutteurs), deux « sous-groupes marginaux » qui sont constamment en conflit avec les ñeeñɓe. En m’appuyant, de manière réflexive, sur ma position de chercheur/musicien/haalpulaar/dimo (noble) originaire du village et sur mon parcours, j’interrogerai le rôle et la place dans la société de trois des acteurs mentionnés : les coolooji, les ñeeñɓe et les mbiruuji. À partir de la description ethnographique et de l’analyse anthropologique des divers modes opératoires du yano (procédé de plaisanterie) – qui permettent d’activer ou de désactiver le denɗiraagal, parenté à plaisanterie – dans leur articulation avec la musique, il s’agira de se demander de quelle manière les coolooji, les ñeeñɓe et les mbiruuji se définissent et contribuent à définir autrui à travers le yano et la musique. Ainsi, la première partie de cette thèse proposera, au-delà de la présentation du contexte historique et social de la commune et du village de Djéwol, un regard synoptique sur les musiques haalpulaar et soninké de la région du fleuve Sénégal. La deuxième partie s’intéressera quant à elle à l’origine des différents types de parenté jiidugal (parenté) et de denɗiraagal (parenté à plaisanterie) procédant par le yano, ainsi qu’à l’art musical associé à ce dernier. Enfin, la dernière partie, consacrée à l’analyse des interactions, conflictuelles ou non, et de l’absence d’interactions entre les coolooji, les ñeeñɓe, et les mbiruuji, mettra en évidence les similitudes et les différences entre ces trois figures. La situation sera finalement analysée à la lumière des reconfigurations contemporaines et de l’évolution des liens de denɗiraagal sur les réseaux sociaux. [less ▲]

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See detailAssessing microbial diversity changes associated with different tillage and crop residue managements: study case in a loamy soil
Degrune, Florine ULg

Doctoral thesis (2017)

The major challenge of modern agriculture is to produce enough food for the growing population, and at the same time, minimize environmental harm. To meet this challenge, Agroecology aims to replace non ... [more ▼]

The major challenge of modern agriculture is to produce enough food for the growing population, and at the same time, minimize environmental harm. To meet this challenge, Agroecology aims to replace non-renewable external inputs with ecological processes to diversify the ecosystem services and attenuate the dis-services of agriculture. In this light, the ability to manage the soil microbiota, that has great effects on soil quality, is receiving attention. Plowing, the most widely used tillage practice in intensive agriculture has proven its efficiency in maximizing crop productivity, but its long term detrimental effects on soil quality, such as soil erosion and organic matter loss, have called for alternative tillage practices. However, the success of the implementation of these practices in Europe is still debated. In the upper part of Wallonia (Belgium), the soil is highly fertile and 80% of land is occupied mostly by intensive cropping systems. To date in Walloon cropping systems, few studies have explored the soil microbiota in association with different soil managements. Here, we used a meta-barcoding approach to explore differences in soil microbial community structure under two contrasting tillage regimes, conventional (CT) and reduced tillage (RT), either with or without crop residue retention. The effects of these soil treatments were explored at different depths and during the growing season of two crops. Our work demonstrated clear differences in microbial diversity between tillage regimes, but no clear differences between residue management practices. The observed differences appeared to be associated with differences in physical (e.g. structure and moisture) and chemical (nutrients) soil properties. Notably, the nutrient concentrations and moisture were higher under CT than under RT. Overall, soil under CT had higher or similar microbial diversity than under RT. Analysis of β-diversity revealed differences in the taxonomic structure of microbial communities. Certain microbial groups were more abundant under CT than under RT and vice versa. For example, mycorrhizal fungi, economically and ecologically important in agroecosystems, were more abundant under RT. Finally, the magnitude of tillage effects on the microbial diversity varied strongly with the sampling depth, whereas it varied moderately with the growing season. This work highlighted CT was not necessarily unfavourable in maintaining microbial diversity when compared to RT. However, the study raises new questions regarding the impacts of microbial diversity changes on soil functioning. We encourage researchers to undertake further investigations into the functional role of microbiota in order to improve our understanding of agroecosystem functioning and its sustainability. [less ▲]

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See detailOffline Policy-search in Bayesian Reinforcement Learning
Castronovo, Michaël ULg

Doctoral thesis (2017)

This thesis presents research contributions in the study field of Bayesian Reinforcement Learning — a subfield of Reinforcement Learning where, even though the dynamics of the system are un- known, the ... [more ▼]

This thesis presents research contributions in the study field of Bayesian Reinforcement Learning — a subfield of Reinforcement Learning where, even though the dynamics of the system are un- known, the existence of some prior knowledge is assumed in the form of a distribution over Markov decision processes. In this thesis, two algorithms are presented: OPPS (Offline Prior- based Policy Search) and ANN-BRL (Artificial Neural Networks for Bayesian Reinforcement Learning), whose philosophy consists to analyse and exploit the knowledge available beforehand prior to interacting with the system(s), and which differ by the nature of the model they make use of. The former makes use of formula-based agents introduced by Maes et al. in (Maes, Wehenkel, and Ernst, 2012), while the latter relies on Artificial Neural Networks built via SAMME (Stagewise Additive Modelling using a Multi-class Exponential loss function) — an AdaBoost algorithm developed by Zhu et al. in (Zhu et al., 2009). Moreover, we also describe a comprehensive benchmark which has been created to compare Bayesian Reinforcement Learning algo- rithms. In real life applications, the choice of the best agent to fulfil a given task depends not only on their performances, but also on the computation times required to deploy them. This benchmark has been designed to identify the best algorithms by taking both criteria into account, and resulted in the development of an open-source library: BBRL (Benchmarking tools for Bayesian Reinforcement Learning) (https://github.com/mcastron/BBRL/wiki). [less ▲]

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See detailLa participation et l’Appropriation à l’épreuve des pouvoirs dans les projets ruraux à Cobly (Atacora-Bénin). Une approche socio-historique
Gbénahou, Hervé Bonaventure Mêtonmassé ULg

Doctoral thesis (2017)

Generally, projects are analyzed when they still ongoing or just at the end. Similarly, the analysis of power issues is generally being focused, in projects cases, on the problems of coordination and ... [more ▼]

Generally, projects are analyzed when they still ongoing or just at the end. Similarly, the analysis of power issues is generally being focused, in projects cases, on the problems of coordination and conflicting relations and their foundations. This doctoral thesis goes a little at the antipodes of these studies. First, it questions closed projects. Afterwards, even if it integrates the conflicting vision of power because of the closed nature of the projects, it additionally uses an alternative approach of power based on "powers of action". Concretely, it takes interest in the projects that the Dutch and Belgian agencies have carried out in the municipality of Cobly in the North-West of Benin. To do so, it closely looks at the participation systems and the appropriation mechanisms designed and implemented in the constituted arenas. It also questions the intervention frameworks and the projects publicizing process. Plus, it seeks to know how the beneficiaries use, the supports that directly reach them or they "hijack", for their empowerment. In doing so, it has taken the option to refocus reflection on the causes of problems and the actors really concerned. The methodological approach used for this research is a mix of sociohistory and biographical approach. It clearly appears, from the results and analyzes made, that the forms of formalized partnerships, the use of participation and the otherness of introduced clustering models have led to "negative" organizational governance, approximate results and differential appropriation's. The various mediated powers and the feelings they have left at actors’ level, have played a great role in these objectified situations. Socio-historical literature requires that the stakes associated with the interactions made possible by the projects, the participation modalities and the fundamentals of POs governance been co-constructed. Similarly, it asks that the learning systems and the capacities of the beneficiaries be constantly put into perspective through oriented decision-making processes. This literature also reveals that the scales generally used to evaluate the impact of projects have always rendered elusive, not only their real effects on the "Powers to act" of the beneficiaries, but also and above all, the effects of the powers they reinforce, on the trajectories of life of beneficiaries. [less ▲]

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See detailTrees and shrubs influence the behaviour of grazing cattle and rumen fermentation
Vandermeulen, Sophie ULg

Doctoral thesis (2017)

Hedgerows and woody strips have been used to enclose fields but declined due to the loss of a direct economic value, abandonment of traditional management techniques and agricultural intensification ... [more ▼]

Hedgerows and woody strips have been used to enclose fields but declined due to the loss of a direct economic value, abandonment of traditional management techniques and agricultural intensification. Nowadays, shrubs and trees on pastures are promoted again through environment-friendly policies and the interest in using them as forage for ruminant increases in both temperate and tropical ecosystems. Woody plants on farmland could yield a wide range of ecosystem services and provide benefits for farmers and their animals such as forage supply to livestock, animal protection against severe weather and reduced parasitic infestation. Moreover, shifts in digestive physiology can be observed that will in turn affect the welfare and the performances of the animal and the production system as a whole. Therefore, in order to contribute to the development of sustainable systems using shrubs and trees as a feed component in its full right, the aim of this work was to investigate the influence of trees and shrubs on the behaviour of grazing cattle and their selectivity towards woody species, and to determine the changes induced by temperate and tropical shrub and tree species on rumen fermentation. Firstly, the behaviour of grazing dairy heifers was recorded during the whole grazing season as well as their selectivity towards temperate woody species in a hedge. It was concluded that having access to a hedge influenced the behaviour of grazing cattle, as the animals ingested woody plants in each season but mostly when the available pasture biomass was lower. The most selected species were Carpinus betulus, Corylus avellana, Cornus sanguinea and Crataegus monogyna. Secondly, the chemical composition, in vitro rumen fermentation profile and protein precipitation capacity (PPC) of the temperate shrub and tree species were measured. The analyses showed that Fraxinus excelsior presented the most interesting profile in terms of chemical composition and in vitro fermentation production. Among the preferred species, C. monogyna and C. avellana produced lower CH4 and the latest had the highest PPC. Thirdly, three newly-developed cultivars of the tropical Desmanthus genus were studied for their effects on in vitro rumen fermentation including potential to reduce CH4. Desmanthus leptophyllus and D. bicornutus had the highest anti-methanogenic potential, and D. bicornutus was more digestible. In conclusion, both temperate and tropical shrub and tree fodder are promising to supplement cattle with good quality forage. Cattle can browse woody species voluntarily, however, further investigations are needed to provide relevant practical recommendations on how to manage this resource adequately in order to balance intake by the animal and regrowth capacity of the plant. The impact of management strategies relying on cutting and preservation should also be assessed. Moreover, benefits of shrubs and trees on pastures beyond the animal feeding and nutrition are still poorly characterized while, in an agroecological perspective, they can contribute to a significant improvement of the sustainability of ruminant production systems. [less ▲]

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See detailStratégies linguistiques et identitaires en Belgique : Approche interdisciplinaire des catégorisations, discours et représentations des usages en interaction de francophones vivant en Flandre et de néerlandophones vivant en Wallonie
Dassargues, Alix ULg

Doctoral thesis (2017)

Depuis le XIXème siècle qui a vu s’épanouir le concept de « peuple » sur des critères ethniques et linguistiques, les langues et les identités collectives sont souvent associées. Ce principe s’actualise ... [more ▼]

Depuis le XIXème siècle qui a vu s’épanouir le concept de « peuple » sur des critères ethniques et linguistiques, les langues et les identités collectives sont souvent associées. Ce principe s’actualise notamment dans les identités régionales de Belgique. À l’heure où celles-ci prennent de plus en plus de poids dans une Belgique fédérale en voie de délitement, il convient de s’intéresser aux individus en situation d’allophonie au sein de ces régions unilingues. Ces individus, de plus en plus isolés par la définition dominante des identités subnationales belges, doivent presque nécessairement mettre en place des stratégies linguistiques et identitaires dans leurs interactions sociales. Afin d’étudier ces stratégies linguistiques et identitaires, notre thèse s’articule autour de deux questions de recherche contiguës. Tout d’abord, il s’agit d’expliciter comment des francophones vivant en Flandre et des néerlandophones vivant en Wallonie conceptualisent les/la langue(s) et les/ l’identité(s). Après avoir défini les modalités de conception et les différents contenus de ces concepts, l’analyse se concentre sur les stratégies linguistiques et identitaires que ces informateurs disent mettre en place en situation d’interaction. En convoquant la sociolinguistique, la linguistique cognitive, la psychologie sociale et la sociologie de l’identité, cette thèse se veut interdisciplinaire afin de mettre en lumière au mieux les liens entre langue(s) et identité(s) au sein du processus d’identification de l’individu. [less ▲]

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See detailExploiting random projections and sparsity with random forests and gradient boosting methods - Application to multi-label and multi-output learning, random forest model compression and leveraging input sparsity
Joly, Arnaud ULg

Doctoral thesis (2017)

Within machine learning, the supervised learning field aims at modeling the input-output relationship of a system, from past observations of its behavior. Decision trees characterize the input-output ... [more ▼]

Within machine learning, the supervised learning field aims at modeling the input-output relationship of a system, from past observations of its behavior. Decision trees characterize the input-output relationship through a series of nested ``if-then-else'' questions, the testing nodes, leading to a set of predictions, the leaf nodes. Several of such trees are often combined together for state-of-the-art performance: random forest ensembles average the predictions of randomized decision trees trained independently in parallel, while tree boosting ensembles train decision trees sequentially to refine the predictions made by the previous ones. The emergence of new applications requires scalable supervised learning algorithms in terms of computational power and memory space with respect to the number of inputs, outputs, and observations without sacrificing accuracy. In this thesis, we identify three main areas where decision tree methods could be improved for which we provide and evaluate original algorithmic solutions: (i) learning over high dimensional output spaces, (ii) learning with large sample datasets and stringent memory constraints at prediction time and (iii) learning over high dimensional sparse input spaces. A first approach to solve learning tasks with a high dimensional output space, called binary relevance or single target, is to train one decision tree ensemble per output. However, it completely neglects the potential correlations existing between the outputs. An alternative approach called multi-output decision trees fits a single decision tree ensemble targeting simultaneously all the outputs, assuming that all outputs are correlated. Nevertheless, both approaches have (i) exactly the same computational complexity and (ii) target extreme output correlation structures. In our first contribution, we show how to combine random projection of the output space, a dimensionality reduction method, with the random forest algorithm decreasing the learning time complexity. The accuracy is preserved, and may even be improved by reaching a different bias-variance tradeoff. In our second contribution, we first formally adapt the gradient boosting ensemble method to multi-output supervised learning tasks such as multi-output regression and multi-label classification. We then propose to combine single random projections of the output space with gradient boosting on such tasks to adapt automatically to the output correlation structure. The random forest algorithm often generates large ensembles of complex models thanks to the availability of a large number of observations. However, the space complexity of such models, proportional to their total number of nodes, is often prohibitive, and therefore these modes are not well suited under stringent memory constraints at prediction time. In our third contribution, we propose to compress these ensembles by solving a L1-based regularization problem over the set of indicator functions defined by all their nodes. Some supervised learning tasks have a high dimensional but sparse input space, where each observation has only a few of the input variables that have non zero values. Standard decision tree implementations are not well adapted to treat sparse input spaces, unlike other supervised learning techniques such as support vector machines or linear models. In our fourth contribution, we show how to exploit algorithmically the input space sparsity within decision tree methods. Our implementation yields a significant speed up both on synthetic and real datasets, while leading to exactly the same model. It also reduces the required memory to grow such models by exploiting sparse instead of dense memory storage for the input matrix. [less ▲]

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See detailComment le changement climatique influence-t-il la croissance du hêtre (Fagus sylvatica L.) le long du gradient bioclimatique de la Belgique ? Une approche dendroécologique.
Latte, Nicolas ULg

Doctoral thesis (2017)

Health anomalies (e.g., worsening crown conditions) on beech (Fagus sylvatica L.) observed throughout Europe since the 1990s have raised growing concerns among foresters, particularly about the future ... [more ▼]

Health anomalies (e.g., worsening crown conditions) on beech (Fagus sylvatica L.) observed throughout Europe since the 1990s have raised growing concerns among foresters, particularly about the future behavior of the species in the face of climate change. This PhD research examined the relationship between beech and its environment in the context of global changes using dendroecology, combination of dendrochronology and forest ecology. The radial growth was used to evaluate the effects of global changes, particularly climate change, on beech development and vitality over time along a bioclimatic gradient in Belgium. Various analyses were carried out using dendrochronological tools (pointer years, mean sensitivity, growth-climate correlation, etc.) and modeling approaches (linear and non-linear mixed models, partial least squares regression, etc.) considering several scales: tree, stand and region. Results show that climate predominantly influenced beech growth since the mid-20th century and did so rather uniformly across Belgium. Beech mean sensitivity increased mainly in response to the higher frequency and intensity of summer heat waves and spring droughts. Isolated but pronounced annual growth reductions induced a gradual diminution of mean growth. The increasing influence of climate progressively concealed the effect of local site growing conditions inducing strong between-sites synchronization along the bioclimatic gradient. Increasing mean sensitivity and decreasing mean growth were more pronounced in lowlands than in uplands, and for a given site, older trees are more affected than younger ones. Although mean sensitivity increases and mean growth decreases naturally with age, the climate change effect was much more important than the age effect. Furthermore, within a tree, along the main stem, climate sensitivity slightly decreased from breast height to crown base and strongly increased from crown base to tree top. These results were interpreted based on ecophysiological knowledge of beech. The influences of silviculture, soil compaction and nitrogen deposition (as part of atmospheric pollution) as well as the consequences of the past and future climate change on beech were discussed. Comparisons with other studies in Europe highlighted that beech is affected on a large part of its natural distribution range (except in high altitude and high latitude). Contrary to what one might think, beech is not only affected in the southern limit (Mediterranean). Although growing conditions are more favorable in Belgium, beech has also more to lose. Beech has coped with global change up to now. Although its climate sensitivity increased and its mean growth decreased, diebacks observed these last years in Belgium were scarce and generally scattered. However, considering the upcoming climate change, the phytosanitary risk will undeniable increased. Forest policy should now integrate that risk and prepare managers to anticipate and prevent it. [less ▲]

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See detailDevelopment and implementation of a methodology for hybrid fire testing applied to concrete structures with elastic boundary conditions
Sauca, Ana ULg

Doctoral thesis (2017)

Fire tests remain a precious tool to comprehend the behavior of structures under accidental fire conditions. The common practice in fire testing is to isolate the tested element in a furnace in which the ... [more ▼]

Fire tests remain a precious tool to comprehend the behavior of structures under accidental fire conditions. The common practice in fire testing is to isolate the tested element in a furnace in which the mechanical support conditions are maintained constant throughout the test. However, such tests fail to capture the effect of the structure surrounding the element of interest when this effect cannot be realistically modeled by a free or fixed support condition. It has been observed in large-scale tests that the behavior of entire structures under fire is different compared with the behavior observed in traditional tests on isolated elements. This indicates the importance of capturing accurately the boundary conditions between the element and the remainder of the structure when characterizing the behavior of this element in fire. The literature describes a few attempts at performing fire tests under realistic boundary conditions. In the latter, the tests were still performed on isolated elements but the boundary conditions were updated during the test taking into account the characteristics of the remainder structure. This technique, called hybrid testing, represents an appealing solution to test structural elements under realistic boundary conditions. Hybrid testing is a methodology which offers the advantage of testing singular structural elements (or a group of structural elements) named physical substructure PS while at the same time considering the characteristics of the remainder substructure named numerical NS, thus allowing to model realistic boundary conditions. Pioneering work has been done in the seismic field where this technique is now well described, but the implementation of this methodology for structural fire testing raises important challenges due to the specificities of the field. A few hybrid fire tests have been performed in the past on columns and slabs. Their analysis shows that they all use a similar methodology, which is referred to as the first generation method in this work. The objective of the thesis was to develop and implement a hybrid fire testing methodology on a reinforced concrete beam extracted from a moment resisting frame. Initially, it was intended to build on the first generation method, but after its detailed analysis in the development stage it has been observed that the process can be unstable. The value of the stiffness ratio between the numerical substructure and the physical substructures has been identified as critical in governing the stability of the test, dictating whether the hybrid test needs to be applied in displacement control or force control. This is a severe drawback of the first generation method, as the stiffness ratio is unknown and changing during the test; besides different degrees-of-freedom can require different procedures during the test. Therefore, it has been shown that the first generation method should not be applied as it can lead to instability prematurely during the tests. To overcome the drawbacks of the first generation method, the objective was to develop a new technique that leads to interface equilibrium and compatibility while at the same time is unconditionally stable (i.e. independently of the stiffness ratio). Thus a novel methodology was developed and applied to the case of a concrete beam (PS) being part of a concrete moment resisting frame (NS). The novel method makes use of the PS’s stiffness in addition to the NS’s stiffness as it was the case in the first generation method. The stiffness matrix of the PS is unknown during the test therefore the initial tangent stiffness matrix is considered during the calculations. The latter choice influences the value of the time step to be adopted during the test. Every time step the boundary conditions are updated and it will be discussed how the chosen value can influence the results. A predetermined matrix is used to describe the behavior of the NS during the hybrid fire tests. This approach does not capture the nonlinearity of the remainder but at the same time the implementation is relative simple and the negative effect of the time calculation is eliminated. The procedure to compute the predetermined matrix of the NS is presented in this thesis. One possible direction in the future development of hybrid fire testing is to model the NS in the finite element model. The algorithm of the proposed method is developed and implemented in nonlinear finite element software SAFIR in order to perform virtual hybrid fire tests. The same algorithm is translated in order to be implemented by the company in charge of the control system at the CERIB furnace facility. The thesis also presents a traditional fire test that has been performed on the beam, in order to highlight the differences when testing structural element without and with the real boundary conditions. For the hybrid test, three degrees-of-freedom are controlled at the interface. The furnace facility has an important role to perform successful test where the equilibrium and compatibility are ensured and no instability occurs during the test. The impediments encountered during the tests will be discussed along with the recommendation for a successful hybrid fire test. [less ▲]

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See detailReforming of toluene formed during the gasification of biomass with alumina based catalysts prepared by aqueous sol-gel processes
Claude, Vincent ULg

Doctoral thesis (2017)

Summary in english: The gasification of biomass into bio-syngas (CO+H2) usually goes along with the formation of tars (toluene, naphthalene) which can cause technical problems at the outlet of the reactor ... [more ▼]

Summary in english: The gasification of biomass into bio-syngas (CO+H2) usually goes along with the formation of tars (toluene, naphthalene) which can cause technical problems at the outlet of the reactor. The reforming of these tars via primary catalysts (inside the reactor) or secondary catalysts (outside the reactor) currently appears as the most interesting way from practical and economical point of views. The use of catalysts made of metallic nanoparticles deposited on y-Al2O3 is an efficient combination for tar reforming applications. During this project, an aqueous sol-gel method for the synthesis of y-Al2O3 supports is developed. In the aim of developing catalysts with metallic nanoparticles finely dispersed, supports of y-Al2O3 are modified with a functionalized silicon precursor (3-(2-aminoethylamino)propyltrimethoxysilane, EDAS). The addition of EDAS modifies the properties of y-Al2O3. Samples prepared with other silicon precursors (non-functionalized or functionalized with other chains than the ones of EDAS) highlight that the reactivity of the precursor influences the crystallinity of the support. The presence of a functionalized chain modifies the shape of the crystallites, which leads to a narrower pore size distribution centered on 4 nm and to a higher specific surface area of the support. In order to orientate the project towards the development of either primary or secondary catalysts, catalytic tests are performed with 8000 ppmv of toluene under primary conditions (T = 750-850 °C) with either y-Al2O3 or olivine supports, doped with either 2 wt. % Ni or 10 wt. % Fe. The olivine, known as primary catalyst of reference, shows better performances. In the case of y-Al2O3, the low loading of Ni leads to the formation of a spinel of NiAl2O4 which shows low reducibility, and the doping with Fe favors the y-Al2O3 to a-Al2O3 phase transition of the support. Therefore, the next studies focuse on the development of 10 wt. % Ni/y-Al2O3 catalysts tested in secondary conditions. The reduction of catalysts entirely composed of NiAl2O4 only starts at T = 680 °C during H2- TPR measurements. However, these samples are reduced during the catalytic reforming of 24.000 ppmv of toluene at T = 650 °C. It is demonstrated that under these conditions, toluene is a better reducing agent than H2 or CO, and that the reduction of NiAl2O4 oxide with toluene enables its conversion with a very little formation of coke. For bulk NiO, reduced at low temperatures (T ~ 450 °C), the catalyst does not take advantage of the anti-coking effect brought by the phenomenon of special reduction by toluene, which leads to a quick deactivation of the catalyst by formation of carbon deposit. The addition of a surfactant (stearic acid) during the aqueous sol-gel synthesis efficiently modifies the morphology (mesopores, macropores) of Ni/y-Al2O3 catalysts. Despite a much higher catalytic activity, attributed to a better diffusion of the gaseous reagents, the sample shows a much higher sensibility towards deactivation by coking. It is hypothesized that this weakness is the consequence of the combination of several facts: loss of balance between the reaction rates of toluene cracking and the rates of dissociation-migration of the HO* and O* species + better reducibility of the catalyst, which avoids the phenomenon of special reduction by toluene + presence of large pores, which do not prevent the growth of filamentous carbon. A vast screening of catalysts composed of 10 % Ni/y-Al2O3 and doped with metals (Cu, Mn, Fe, Mo or Mn) or oxides (CaO, K2O, MgO or CeO2) is performed. The samples doped with Mn, Mo, Ca ou K show the most interesting catalytic activities and resistances against coking. It is to notice that, for an identical amount, the samples doped with two different elements (Co+Mo, Mn+Mo, Ca+K or Ce+K) show better catalytic performances compared to those doped with only one type of dopant. The tests of the best catalysts in long-term conditions (30 h) or in presence of H2S are promising. Hence, these catalysts might be adequate for industrial applications. Résumé français: La gazéification de biomasse en bio-syngas (CO+H2) s’accompagne généralement de formation de goudrons (toluène, naphtalène) qui peuvent causer des problèmes techniques en aval du réacteur. Le reformage de ces goudrons via un catalyseur primaire (à l’intérieur du réacteur) ou secondaire (en sortie du réacteur) apparaît actuellement comme la méthode la plus intéressante d’un point de vue pratique et économique. L’utilisation de catalyseurs constitués de nanoparticules métalliques supportées sur y-Al2O3 est une association efficace pour le reformage catalytique de goudrons. Une méthode de synthèse de support y-Al2O3 par voie sol-gel aqueuse est mise au point durant ce projet. Dans l’optique de synthétiser des catalyseurs composés de nanoparticules métalliques finement dispersées, des supports en y-Al2O3 sont modifiés avec un précurseur de silice fonctionnalisé : l’EDAS (3-(2-aminoéthylamino)propyltriméthoxysilane). L’addition d’EDAS modifie les propriétés texturales du support y-Al2O3. Des échantillons préparés avec d’autres types de précurseurs de silice (non-fonctionnalisés ou fonctionnalisés avec d’autres chaînes que celle présente dans l’EDAS) mettent en évidence le fait que la réactivité du précurseur de silice influence la cristallinité du support. La présence d’une chaîne fonctionnalisée modifie quant à elle la forme des cristallites d’alumine, menant ainsi à une distribution de taille de mésopores plus étroite et centrée à 4 nm et une plus grande surface spécifique du support. Afin de déterminer quel type de catalyseurs synthétiser (primaires ou secondaires), le reformage catalytique de 8000 ppmv de toluène en conditions primaires (T = 750-850 °C) est effectué avec des supports constitués de γ-Al2O3 ou d’olivine, dopés avec 2 % Ni ou 10 % Fe. L’olivine, catalyseur primaire de référence, présente de meilleurs résultats pour le reformage du toluène. Dans le cas de y-Al2O3, le faible dopage en Ni conduit à la formation d’un spinelle NiAl2O4 difficile à réduire, et le dopage avec Fe favorise la transition de phase de y-Al2O3 vers a-Al2O3. Les travaux suivants sont donc axés sur le développement de catalyseurs de type 10 % Ni/y-Al2O3 testés en conditions secondaires. La réduction de catalyseurs constitués d’une unique phase de NiAl2O4 ne s’initie qu’à partir de T = 680 °C lors de mesures en température programmée sous H2 (TPR). Cependant, ceux-ci sont réduits lors du reformage catalytique de 24.000 ppmv de toluène à T = 650 °C. Il est démontré que dans ces conditions, le toluène est un meilleur agent réducteur que H2 ou CO, et que la réduction des espèces NiAl2O4 par le toluène permet de convertir celui-ci en syngas tout en prévenant la formation de coke. Lors de la présence de NiO réduit à plus basse température (T ~ 450 °C), le catalyseur ne tire pas avantage du phénomène de réduction spécial des oxydes métalliques par le toluène, ce qui entraîne ainsi la désactivation rapide du catalyseur par cokage. L’ajout d’un surfactant (acide stéarique) lors de la préparation par voie sol-gel aqueuse s’avère efficace afin de modifier la morphologie (mésopores, macropores) de catalyseurs Ni/y-Al2O3. Malgré une activité catalytique nettement plus élevée, attribuée à une meilleure diffusion des réactifs, l’échantillon montre des tendances beaucoup plus importantes à se désactiver par cokage. On émet l’hypothèse que cette faiblesse est due à une combinaison de plusieurs faits: déséquilibre entre la réaction de cracking du toluène et les réactions de dissociation-migration des espèces HO* et O* + meilleure réductibilité empêchant de tirer avantage du phénomène de réduction spécial par le toluène + présence de larges pores ne restreignant pas la croissance de carbone filamentaire. Un large screening de catalyseurs 10 % Ni/y-Al2O3 dopés avec des métaux (Cu, Mn, Fe, Mo ou Mn) ou des oxydes (CaO, K2O, MgO ou CeO2) est effectué. Les échantillons contenant les éléments Mn, Mo, Ca ou K s’avèrent les plus intéressants de par leur activité catalytique et leur résistance au cokage. Pour une même quantité massique ajoutée, les échantillons constitués d’associations de dopants (Co+Mo, Mn+Mo, Ca+K ou Ce+K) affichent de meilleures performances catalytiques que ceux effectués avec un seul dopant. Les résultats obtenus avec les meilleurs catalyseurs lors de tests catalytiques de longue durée (30 h) ou en présence de H2S sont prometteurs. Ceci porte à croire que ces catalyseurs pourraient convenir à une application industrielle. [less ▲]

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See detailThe interplay of regional systems of innovation, strategic alliances and open innovation
Segers, Jean ULg

Doctoral thesis (2017)

Modern biotechnology is a driving force and a full grown industry in the international economy with ongoing and rapid innovations. The emphasis of this dissertation is on the valorization of red biotech ... [more ▼]

Modern biotechnology is a driving force and a full grown industry in the international economy with ongoing and rapid innovations. The emphasis of this dissertation is on the valorization of red biotech, i.e. pharmaceutical and healthcare applications. Belgium has firmly established itself as an international red biotechnology country, with a world class biotechnology industry in the Flanders and Wallonia bioRegions. Developing a domestic biotechnology industry - and hence new biotechnology firms - can be influenced by regional policy. The pharmaceutical-biotechnology regional and sectoral innovation system is characterized as an international and dynamic network architecture involving numerous players engaged in drug discovery. Regional governments and dedicated public and private network organizations have supported emerging new biotechnology firms by providing critical resources and by promoting an institutional environment that has enabled partnerships between universities, highly specialized research centers, small science based academic spin-offs and corporate spin-outs and large global pharmaceutical companies. Both policy and big firms look at the new biotechnology firms from a strategic point of view. The policy objective is the emergence of new and sustainable firms in the region; the big firms objective is the filling or renewal of the pipelines of products. New biotechnology firms are both beneficiaries and targets of strategic partnering alliances with large and global (bio)pharmaceutical companies. A number of the Belgian new biotechnology firms hold a nodal position as “ most preferred partner ” with multiple alliances in dynamic R&D networks. They have a high degree of integration into global technological networks through strategic alliances. Strategic alliances and open innovation are commonly leveraged. Despite their small size and relative immaturity, some of the new biotechnology firms are able to adopt innovative business models by providing R&D and services to large biopharmaceutical companies and by cooperating with them through open innovation. [less ▲]

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See detailThree Essays on Conditional Accounting Conservatism
Boussaid, Nabila ULg

Doctoral thesis (2017)

Accounting conservatism is one of the oldest concepts in accounting, yet it is one of the most controversial topics nowadays. While there is little debate on the existence of accounting conservatism ... [more ▼]

Accounting conservatism is one of the oldest concepts in accounting, yet it is one of the most controversial topics nowadays. While there is little debate on the existence of accounting conservatism practices, the drivers and the implications of these accounting practices show considerable divergence between accounting researchers and standard setters (such as FASB/IASB). In their 2010 conceptual frameworks, the FASB and IASB removed conservatism from the qualitative characteristics of financial reporting. This decision has been the subject of considerable criticism from accounting researchers and has sparked a new debate on the mechanisms driving accounting conservatism as well as its benefits to market participants. This dissertation contributes to this new debate by providing three empirical essays on accounting conservatism. The first essay (Chapter 2) is part of the literature investigating the relation between accounting conservatism and corporate governance mechanisms. It documents that board attributes are important determinants of conservatism in financial reporting of French firms. The second essay (Chapter 3) extends the previous study and examines how the relation between board attributes and accounting conservatism varies across three European countries, namely, France, Germany and the UK. This essay emphasizes that the relationship between board characteristics and accounting conservatism is country dependent. Taken together, these two essays expand our understanding of how corporate governance mechanisms influence accounting quality. The third essay (Chapter 4) focuses rather on the informational benefits of accounting conservatism to financial market participants. This essay shows, in particular, that accounting conservatism improves the performance of analysts’ forecasts as well as the stock market liquidity. Overall, the main message to take away from this research is that accounting conservatism is closely related to corporate governance mechanisms and offers a powerful tool to provide verifiable information. [less ▲]

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See detailEmergence du sujet-entrepreneur au Cameroun. L'engagement entrepreneurial saisi par la réappropriation subjective d'expériences socio-biographiques
Amougou, Gérard ULg

Doctoral thesis (2017)

Cette recherche traite de la dynamique de subjectivation portée par la figure du sujet-entrepreneur, évoluant en dehors du sérail étatique au Cameroun. Son expérience biographique laisse percevoir un ... [more ▼]

Cette recherche traite de la dynamique de subjectivation portée par la figure du sujet-entrepreneur, évoluant en dehors du sérail étatique au Cameroun. Son expérience biographique laisse percevoir un modèle d’engagement dit entrepreneurial qui l’inscrit au cœur de l’histoire sociale et politique en cours. Le récit de vie laisse percevoir un souci pressant de réalisation de soi qui le pousse à relativiser les supports institutionnels classiques, et non moins contraignantes, de socialisation. Durant son parcours, la démarcation de ces dernières conduit à la répugnance d’une carrière administrative « tranquille » et est assortie d’un discours critique sur la politique du ventre. Cette démarcation serait en outre au cœur d’une rupture biographique qui l’astreint à s’engager, de manière individualisée, à la promotion d’une société utopique à partir de son champ professionnel. Son engagement présente une variété de typologies d’action liées à la sensibilité et aux convictions personnelles, à l’expérience acquise au cours de la trajectoire biographique, et à l’orientation donnée à l’activité. Cette variété d’actions trouve un lieu commun dans le besoin de subvertir l’ordre sociopolitique dominant en vue de promouvoir l’avènement d’une cité alternative. En cela, les logiques d’action du sujet-entrepreneur s’inscrivent dans une dynamique historique de subjectivation qui informe les processus d’individualisation. [less ▲]

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See detailLe moment de l'illusion dans la déhiscence du sujet et de son monde. Perspectives anthropo-téléologiques depuis Kant et Winnicott.
Notturni, Loris ULg

Doctoral thesis (2017)

Quelle pourrait être la raison pour laquelle les philosophes, d'habitude si labiles et si doctes sur tous les sujets, sont si peu enclins à se pencher sur un berceau ? Pourquoi, la plupart du temps, les ... [more ▼]

Quelle pourrait être la raison pour laquelle les philosophes, d'habitude si labiles et si doctes sur tous les sujets, sont si peu enclins à se pencher sur un berceau ? Pourquoi, la plupart du temps, les philosophes éludent-ils dans leur discours sur la subjectivité humaine ses débuts et sa fin, c'est-à-dire son histoire réelle ? Le présent travail n'a pas l'ambition de répondre à ces questions mais de pallier ce manque : élucider de manière originale l'histoire de la subjectivité humaine vivante et fournir les moyens pour en rendre compte de manière consistante. En philosophie contemporaine, et plus particulièrement en phénoménologie, tout se passe souvent comme si la notion de subjectivité constituait, à l'instar de l'objectivité, autant une évidence souveraine qu'un simple concept opératoire. Mais, paradoxalement, lorsque le philosophe prononce le mot : « subjectivité », il ne nous met rien sous les yeux, et l'on pourrait aller jusqu'à se demander si la réalité de ce concept a d'autres conditions formelles et matérielles que sa propre énonciation. Pour notre part, nous suspecterions bien plutôt que l'opérativité technique et la « souveraineté » ontologique de cette notion de subjectivité s'appuient toutes deux et en secret sur un réalisme métaphysique implicite du sujet, caractéristique de la Modernité et dont nous sommes toujours tributaires, réalisme alimenté en sous-main par d'incessants réaménagements sémantiques et d'innombrables effets de polysémie. Lorsque l'on emploie le mot « subjectivité », de quoi parle-t-on exactement ? Nous tenterons de clarifier cette question afin de pouvoir y répondre. Notre travail de recherche vise à réinterroger ce réalisme chronique de la subjectivité humaine en redéfinissant cette notion à la lumière de sa propre histoire. En ce qui nous concerne, le ressort initial de ce projet philosophique fut la coïncidence heureuse entre, d'une part, les interrogations cliniques issues de l'observation empirique des débuts de l'invidualité subjective humaine par un pédiatre anglais, Donald Woods Winnicott (1896-1971) et, d'autre part, la redéfinition radicale que la pensée critique d'Emmanuel Kant (1724-1804) a infligée à cette notion de subjectivité. Cette simple coïncidence thématique ne justifie pas à elle seule une recherche doctorale. Le motif essentiel légitimant la convocation d'auteurs aussi étrangers l'un à l'autre tient, avant toute chose, dans la nécessité des problèmes qu'ils ont dégagés dans leurs champs disciplinaires respectifs à propos de la subjectivité humaine. Pour résumer de manière générale, nous dirions à ce stade que la nécessité problématique principale qui, selon nous, croise les trajectoires intellectuelles kantienne et winnicottienne est la redéfinition de la notion de subjectivité à partir d'une autre notion, elle-même redéfinie : celle d'illusion. Selon nous, cette révision se diffracte sur trois plans épistémologiques différents, de complexité différente et non réductibles l'un à l'autre : premièrement, la subjectivité entendue comme objet possible d'une science pure a priori serait une illusion ; deuxièmement, l'illusion serait un mode constitutif de l'esprit subjectif dans ses rapports à certains objets, la subjectivité se définissant ici par son activité judicatoire ; troisièmement, l'illusion serait constituante du rapport de la subjectivité à elle-même et à son monde, entendue comme subjectivité humaine vivante. Ces trois « thèses » ne sont recevables qu'à la condition de bien entendre que les notions de subjectivité et d'illusion ont, à chaque niveau, des acceptions différentes. Notre étude visera à redéfinir ces deux notions et rendre manifeste leur intimité épistémologique, phénoménologique et génétique. Enfin, notre contribution personnelle permettra de montrer, preuves à l'appui, qu'il y a une filiation méthodologique, implicite et souterraine, jusqu'ici passée totalement inaperçue, entre Kant et Winnicott. En bref, nous affirmons que la pensée clinique de Winnicott et, plus particulièrement, son approche clinique de la genèse empirique de l'individualité subjective humaine dans le temps, se présente comme une réactualisation inaperçue et originale (à l'insu de l'auteur lui-même) des opérateurs épistémologiques et phénoménologiques et, d'une manière générale, du mode de pensée que Kant déploie dans la Critique de la faculté de juger. Enfin, nous montrerons que le concept d'illusion chez Winnicott, dont l'opérativité épistémologique et phénoménologique s'inscrit dans le droit fil de la pensée critique kantienne et de l'anthropologie hégélienne, réverbère un mode légitime d'appréciation de la subjectivité humaine vivante qui pourrait être d'une utilité précieuse pour l'anthropologie philosophique. En résumé, notre travail personnel s'est développé à partir de deux sources principales : la pensée clinique winnicottienne, entendue comme structure élective de phénomènes et de problèmes nécessaires, et la pensée critique kantienne, entendue comme garant épistémologique mettant à notre disposition une méthodologie fiable et puissante. Il ne s'agit ni d'une thèse « sur » Kant, ni d'une thèse « sur » Winnicott, mais d'un travail philosophique personnel réalisé à partir de l'intérêt suscité par ces auteurs et leurs démarches respectives. La première partie consistera en un préambule historique, guidé par une question capitale : par quels processus historiques et idéologiques la notion d'illusion, lourdement marquée par son passé métaphysique et diverses acceptions péjoratives remontant à l'Antiquité, en est-elle arrivée à être assumée au dix-huitième siècle chez Kant comme un opérateur épistémologique de premier plan, à savoir une disposition transcendantale de notre esprit (entendu comme faculté de connaissance) ? Dans la deuxième partie, nous développerons deux questions. La première, d'ordre épistémologique, pourrait être résumée comme suit : à quelle consistance épistémologique peut prétendre une description de la subjectivité humaine vivante ? La seconde question, dont la teneur sera essentiellement phénoménologique, sera la suivante : à partir de quand, comment et à quelles occasions la subjectivité humaine en vient-elle à prendre conscience d'elle-même en tant que subjectivité vivante et singulière dans les relations qu'elle entretient avec le monde, d'une part, auquel elle appartient et, d'autre part, duquel elle se différencie ? Une fois le cadre posé dans les termes de la méthodologie kantienne de la Critique de la faculté de juger, nous réactualiserons notre interrogation de la subjectivité humaine vivante et de son histoire à partir de la pensée clinique de Winnicott, tout en prenant la mesure de la consistance de son propos, grâce et par-delà Kant. La double question qui guidera la troisième partie se présentera comme suit : d'une part, quelles sont les questions épistémologiques qui émergent de la pratique pédopsychanalytique de Winnicott et, d'autre part, à quel point cette pratique, co-extensive à un champ disciplinaire spécifique, permet-elle de renouveler en profondeur, par son approche théorico-expérimentale et les questions nécessaires qui en émergent, la réflexion philosophique sur la subjectivité, son émergence et sa réalité ? [less ▲]

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See detailAERODYNAMIC AND AEROELASTIC MODELING OF HORIZONTAL AXIS WIND TURBINES USING PANEL METHODS
Prasad, Chandra Shekhar ULg

Doctoral thesis (2017)

Wind energy is one of the most reliable renewable energy sources and constitutes a viable alternative to fossil and nuclear fuels for the generation of electricity. Over the last couple of decades the ... [more ▼]

Wind energy is one of the most reliable renewable energy sources and constitutes a viable alternative to fossil and nuclear fuels for the generation of electricity. Over the last couple of decades the increasing demand for wind energy has resulted in increasingly large and sophisticated wind turbines. Accurate but efficient aerodynamic and aeroelastic modelling at the design stage has become a key issue. The surface panel and vortex lattice methods are efficient aerodynamic modelling tools that are routinely employed in design calculations by the aerospace industry. They constitute a good compromise between fidelity and computational cost in the preliminary design and optimization phase. However, these approaches have not been widely adopted for wind turbine modelling due to their inability to represent separated flow. The main objective of this thesis is the development of a 3D unsteady viscous-inviscid interaction technique that couples panel methods to a boundary layer solution and can be used to model separated flow over the blades of a wind turbine rotor. The technique is based on a quasi-3D, quasi-steady integral boundary layer solution, coupled to a 3D unsteady surface panel method by means of a two-way interaction scheme. The boundary layer solution results in an estimate of the separation line on the suction surface of the blade. A separated shear layer made up of doublet panels is shed from this line and allowed to propagate freely at the local flow velocity, exactly like the wake shed at the trailing edge. Aerodynamic pressure and load predictions obtained from this method are validated through comparison to experimental measurements from the NREL phase VI wind turbine. The thesis also describes the development of a complete methodology for the unsteady aeroelastic and aeroservoelastic modeling of horizontal axis wind turbines at the design stage. The methodology is based on the implementation of unsteady aerodynamic modeling, advanced control strategies and nonlinear finite element calculations in the Siemens LMS Samcef for Wind Turbines design package. The aerodynamic modelling is carried out by means of the unsteady Vortex Lattice Method. The complete methodology is used to perform full aeroservoelastic simulations of a 2MW prototype wind turbine model. [less ▲]

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See detailDEVELOPMENT OF FUNCTIONAL MICELLES FROM BIODEGRADABLE AMPHIPHILIC BLOCK COPOLYMERS FOR DRUG DELIVERY AND TUMOUR THERAPY
Gulfam, Muhammad ULg

Doctoral thesis (2017)

Drug delivery systems in the size range of ~ 10-250 nm are enabling tools for the site-specific targeting and controlled release applications. To take advantage of these capabilities, various nanocarriers ... [more ▼]

Drug delivery systems in the size range of ~ 10-250 nm are enabling tools for the site-specific targeting and controlled release applications. To take advantage of these capabilities, various nanocarriers e.g., micelles, dendrimers, liposomes, nanoparticles, nanocapsules, nanotubes, and nanogels have been designed for drug delivery. Specifically, micelle-based drug carrier systems have emerged as promising tools for site-specific delivery and controlled release applications. Despite several advantages over conventional drugs, some limitations of micelle-based drug delivery have also been reported. These drawbacks include low stability in vivo, poor penetration, modest accumulation in tumor tissues, and inadequate control over drug release. To overcome these limitations, stimuli-responsive or smart polymeric nanocarriers have been developed for drug delivery and tumour therapy, previously. The most well-known internal stimuli in cancerous regions include higher acidity associated with dysregulated metabolism in tumour tissues, elevated levels of glutathione in the cytosol and nucleus of cancer cells, and altered degradative enzymes in the lysosomes, and reactive oxygen species in the mitochondria. These intrinsic microenvironments can be exploited as internal stimuli to attain active drug release in the tumor tissues or cancer cells. Particularly, the reducing potential inside the cancer cells is considerably higher than found in the extracellular environment and bloodstream. Therefore, such varying redox potential can be exploited for tumor specific drug delivery and controlled release applications. Various types of redox-responsive micelles have been developed previously. Generally, redox responsive micelles have disulfide linkages that undergo rapid cleavage in the presence of reducing agents in the intracellular components, however, are stable at oxidizing extracellular environment. The redox-responsive disulfide bridges can be incorporated into nanocarriers by placing multiple disulfide bonds in the hydrophobic backbone or by conjugating therapeutic agents to the side chain of the polymer via a disulfide linker. Another strategy to construct redox-responsive linkages is to crosslink the polymeric nanocarriers with a disulfide crosslinker. It has been studied that polymeric micelles can dissociate, especially upon administration when they are diluted below their critical micelle concentration. The stability of polymeric micelles can be enhanced by chemical crosslinking. Various types of crosslinked micelles can be prepared subjected to the localisation of the crosslinking, e.g. shell crosslinked micelles, and core crosslinked micelles. Introducing redox-responsive bridges by disulfide crosslinker may not only provide stability to nanocarriers against dilutions during circulation, but also render them responsive to reduction conditions. Specifically, redox-responsive core-crosslinked micelles have demonstrated good stability and better ‘stealth’ properties, however, the hydrophobic cores of most of the existing core-crosslinked micelles have been based on non-degradable polymers such as polyacrylamide or polyacrylate. The non-degradable constituent of the block copolymer may cause complications in clinical applications. Therefore, reduction-responsive core-crosslinked micelles comprising entirely of biologically inert or biocompatible and biodegradable polymers would be better candidates for drug delivery and controlled release application. To overcome these limitations, micelles based on polyesters (a class of aliphatic biodegradable polymers) can used for drug delivery application. In the last few decades, various FDA approved aliphatic polyesters e.g. poly(lactic-co-glycolic acid) (PLGA), poly(ε-caprolactone), and poly(lactic acid), have been intensively studied to exploit their potential in drug, gene and protein delivery and controlled release applications. However, most of these polyesters lack functional groups which make it difficult to incorporate redox-responsive linkages to core-crosslink their micelles. To address these issues, we have synthesized functional biodegradable and biocompatible block copolymers based on mPEG-b-poly(εCL-co-αClεCL). The pendent chloro groups of the block copolymer were converted into azides using nucleophilic substitution reaction to produce mPEG-b-poly(εCL-co-αN3CL) block copolymer as a precursor of reactive polymeric micelles. The synthesized polymers were characterized by NMR, FT-IR and size exclusion chromatography (SEC). Micelles were prepared using dialysis method and methotrexate (an anticancer drug) was loaded into the hydrophobic core of the reactive micelles. Micelles were subsequently crosslinked by a redox-responsive bis-alkyne ethyl disulfide crosslinker. The size distributions and morphology of core-crosslinked micelles were assessed using dynamic light scattering (DLS) and transmission electron microscopy. The drug release studies were performed under simulated non-reducing and reducing conditions. Cellular uptake studies in human breast cancer cells (MCF7 cells) were performed using Oregon-green loaded core-crosslinked micelles. The MTX-loaded core-crosslinked micelles were assessed for their cytotoxicity in human breast cancer cells by MTT assays. The apoptosis inducing potential of MTX-loaded core-crosslinked micelles was analysed using Hoechst/PI assays and was further probed by annexin-V/PI assays. The data from these studies indicate that drug release from these cross-linked micelles can be controlled and that the redox-responsive micelles are more effective carriers for MTX than non-cross-linked analogues in the cell-lines tested. In another strategy, a multifunctional amphiphilic block copolymer based on α-amine-PEG-b-poly(εCL-co-αN3εCL) was synthesized and subsequently was used to conjugate methotrexate on the hydrophilic block for receptor mediated targeting of breast cancer cells. Cellular uptake studies revealed 2.3-fold higher uptake of MTX-conjugated micelles as compared with un-conjugated micelles. The blank micelles showed low cytotoxicities in breast cancer cells, however, MTX-conjugated micelles exhibited greater antitumor activities in contrast to free-MTX. We hypothesize that these functional micelles could be potentially powerful nanocarriers for stimuli-responsive controlled release, active tumour targeting and therapy. [less ▲]

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See detailTHE IMPACT OF SURFACTANTS ON VEGETBLE WHIPPED CREAM PROPERTIES IN RELATION WITH THE EMPLOYED FAT
Petrut, Raul Flaviu ULg

Doctoral thesis (2017)

Vegetable whipped creams are nowadays a popular alternative to the traditional dairy whipped creams. The emulsions standing at the base of vegetable whipped creams are classified as O/W emulsions. During ... [more ▼]

Vegetable whipped creams are nowadays a popular alternative to the traditional dairy whipped creams. The emulsions standing at the base of vegetable whipped creams are classified as O/W emulsions. During whipping air is incorporated and entrapped by a fat crystallize network. This is achieved by the fat droplets interaction through the partial coalescence mechanism. Hence the presence of a crystalline fat phase is imperative within the formulation of the whipped cream. In order to control the partial coalescence and stabilize both the emulsion and the whipped cream, emulsifiers are required. Therefore in such systems, proteins and LMW surfactants coexists and dictate the degree and rate of partial coalesce. This allows the tailoring of the sensorial attributes and physico-chemical properties of the whipped cream (e.g. stability, overrun, texture). Nevertheless the impact of the components on the whipped cream properties has to be understood as a whole and not as individual effects of fats, proteins and LMW surfactants. [less ▲]

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See detailDépolution des sédiments d’une mangrove de l’estuaire du Wouri : évaluation du potentiel de microflores.
Semboung Lang, Firmin ULg

Doctoral thesis (2017)

L’importance des écosystèmes de mangroves n’est plus à démontrer dans l’équilibre naturel des côtes des régions tropicales. Elles constituent un écosystème particulier et jouent un rôle important dans la ... [more ▼]

L’importance des écosystèmes de mangroves n’est plus à démontrer dans l’équilibre naturel des côtes des régions tropicales. Elles constituent un écosystème particulier et jouent un rôle important dans la production de la biomasse. Mais l’exploitation excessive du bois des palétuviers, les pollutions diverses suite à l’exploitation pétrolière et gazière, sont autant de facteurs qui contribuent à la dégradation des forêts de mangroves. Ainsi, entre 1980 et 2000, environ 35% de la superficie mondiale des mangroves a disparu. La pollution a entraîné une dégradation considérable des mangroves. Une quantité grandissante de déchets résultant des activités urbaines, industrielles et agricoles et de l’exploitation en mer du pétrole et du gaz est rejetée sans aucun traitement dans la mer et se retrouve au niveau des mangroves. Les déversements accidentels d’hydrocarbures en mer entraînent une grave pollution des mangroves et la pollution marine provenant des navires est une menace qui va sans doute s’accroître avec le développement de l’exploitation pétrolière. L’objectif de cette thèse était de mettre au point une méthode de dépollution par voie biologique des sédiments de mangroves pollués par les hydrocarbures. Il s’agissait plus précisément d’évaluer les capacités intrinsèques de dégradation de la microflore spécifique endogène, de comparer le potentiel de dégradation de cette microflore avec d’autres souches pures connues pour leur capacité à dégrader les hydrocarbures et enfin d’évaluer les différentes techniques de biodégradation adaptées pour l’élimination des hydrocarbures dans les sédiments de mangroves. Des procédés biologiques adaptés ont été mis en œuvre au cours de ce travail pour restaurer les écosystèmes de mangroves. Différentes techniques de traitements biologiques impliquant la microflore spécifique endogène ont été mises en œuvre. L’évaluation du potentiel de dégradation de cette microflore a été réalisée par rapport à trois souches pures exogènes. Les résultats obtenus ont montré que le potentiel de dégradation de la microflore spécifique est comparable à celui de Rhodococcus erythropolis lorsqu’on augmente sa concentration dans les sédiments (107 CFU.g-1 de matière sèche). La croissance de cette microflore est accélérée avec la présence des nutriments tels l’azote et le phosphore. Ce qui relève davantage le taux de dégradation des hydrocarbures. Le taux de dégradation obtenu en combinant les traitements par bioaugmentation de la microflore spécifique endogène et biostimulation (86%) nous ont amené à proposer cette méthode pour dépolluer les sédiments de mangroves. L’utilisation de la microflore spécifique endogène évite de travailler avec des souches exogènes qui nous exposent aux problèmes écologiques et éthiques liés à leur utilisation. [less ▲]

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See detailLe travail de la décision. Les processus de l'application des peines en Belgique francophone
Bastard, Joséphine ULg

Doctoral thesis (2017)

Cette recherche porte sur la prise de décision des tribunaux de l’application des peines (TAP), considérée au sein de la série d’actions qui la rend possible. Les décisions de libération anticipée de ... [more ▼]

Cette recherche porte sur la prise de décision des tribunaux de l’application des peines (TAP), considérée au sein de la série d’actions qui la rend possible. Les décisions de libération anticipée de prison se construisent en effet dans des processus longs, en interdépendance avec les acteurs institutionnels dans les établissements pénitentiaires, l’administration centrale en charge des « petites sorties » qui servent à préparer les projets de réinsertion, et les TAP qui finalement valident ou informent ces processus par leur décision motivée. La thèse rend compte de la complexité de la décision collective, en suivant le passage du droit de l’application des peines dans ses trois organisations, la prison, l’administration centrale et le TAP, le long des situations de travail des acteurs. La méthode est inductive, et l’enquête qualitative, constituée d’entretiens semi-directifs, d’observations des acteurs au travail, de lectures approfondies des dossiers et d’observations d’audiences des TAP. L’ensemble de ces matériaux permettent de suivre tous les agents, supports ou lieux de la décision et de reconstituer la trajectoire des cas de l’application des peines, en portant attention aux documents, aux pratiques et finalement au partage de sens entre les acteurs. La thèse vise ainsi à montrer que la décision ne se réduit pas à une situation ou un moment, mais qu’elle est le produit d’un processus, organisationnel, de partage de pratique et de sens, créant les routines de l’action collective. La multiplicité des acteurs sont autant d’épreuves à franchir pour les cas, produisant des jugements multiples sur l’individu et permettant notamment la justification de la décision. La juridictionnalisation, seulement partielle de l’application des peines, introduite en 2006, montre ainsi en pratique un traitement administratif et centralisé des demandes, un système de décision complexifié, qui crée des verrous supplémentaires sans désactiver ceux qui lui préexistaient. [less ▲]

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See detailDevelopment of molecular tools for rapid detection and quantification of indoor airborne molds to assess their impact on public health
Libert, Xavier ULg

Doctoral thesis (2017)

Currently, contamination of the indoor environment by fungi is suggested to be a public health problem, although scientific evidence on the causal link is still limited. The monitoring of indoor airborne ... [more ▼]

Currently, contamination of the indoor environment by fungi is suggested to be a public health problem, although scientific evidence on the causal link is still limited. The monitoring of indoor airborne fungal contamination is a common tool to help understanding the link between fungi in houses and respiratory problems. Classical monitoring methods, based on cultivation and microscopic identification, have some limitations. For example, uncultivable or dead fungi (“unknown” fraction) cannot be identified, although they could have an impact on human health. In this context, molecular tools seem to be a valuable alternative. In this PhD work, different molecular tools were developed, from simplex to multiplex, to detect and identify indoor airborne fungi. The goal was to improve the detection of fungal contaminants, including the “unknown” fraction, as compared to the currently used classical monitoring methods. The necessary air sampling and DNA extraction protocols, adapted to the downstream molecular monitoring methods have also been developed. Through the application of the developed tools to specific case studies, we aimed to improve the current knowledge on fungal contamination. At first, we developed a specific ITS-based SYBR®green real-time PCR (qPCR) assay for Aspergillus versicolor, a species frequently observed in indoor air and known to be allergenic. Additionally, an ITS-based qPCR assay was developed for the specific detection of Exophiala jeanselmei, a pathogenic yeast suspected to be a part of the “unknown fraction”. The performance of these qPCR methods was assessed. This comparison demonstrated that SYBR®green qPCR assays can be used as a molecular alternative for monitoring of contaminated samples while eliminating the need for culturing and thereby considerably decreasing the required analysis time. However, qPCR has some limitations especially concerning the discrimination of genetically close species and multiplexing. The first issue was addressed through the use of post-qPCR high resolution melting (HRM) analysis, providing a proof-of-concept for this approach, using 3 closely related Aspergillus, i.e., A. versicolor, Aspergillus creber and Aspergillus sydowii. This HRM tool will allow a more accurate monitoring of these closely related indoor air contaminants, thereby contributing to an improved insight in the causal link between the specific presence of these species and health issues. The multiplexing issue was overcome through a Luminex xMAP® assay, developed for the simultaneous detection of the 10 most frequently in indoor air found fungi. All the species identified with the classical method were also detected with the xMAP® assay, however in a shorter time frame, and using less sample material. This assay will improve the communication with the involved medical team and the patient. To provide scientific evidence for the causal link between indoor airborne fungi and health problems, the full diversity needs however to be identified. This cannot be achieved by using a targeted assay. Therefore, next generation sequencing (NGS) could offer a valuable alternative as an open approach multiplex monitoring method. An NGS-based metagenomics approach was used to investigate the “unknown” agents in air samples of offices in contact with air-conditioning reservoirs and showed the first detection of E. jeanselmei in indoor air. Finally, a metagenomics analysis was performed to investigate the indoor airborne fungal diversity in contaminated residences in Brussels where people with health problems were living. This demonstrated that NGS could contribute to improved data concerning the indoor airborne fungal diversity, as compared to the currently used classical methods. The methods developed in this PhD work and the insights obtained are a first step for a better understanding of the causal link between indoor airborne fungi and public health. [less ▲]

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