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See detailÉtude du mouvement autorotatif des grues sous vent turbulent
Vanvinckenroye, Hélène ULg

Master's dissertation (2014)

This work aims to study the motion of tower cranes subjected to turbulent wind. Tower cranes are structures composed of a rigid mast and a rotating jig. The jig may exhibit autorotations that could lead ... [more ▼]

This work aims to study the motion of tower cranes subjected to turbulent wind. Tower cranes are structures composed of a rigid mast and a rotating jig. The jig may exhibit autorotations that could lead to partial or total collapse of the structure. The crane is modeled by a single degree-of-freedom oscillator assuming a perfectly rigid jig rotating around a fixed point representing the jig-mast connection. In case of a unidirectional and spatially uniform velocity field, the problem presents strong similarities with a vertically excited pendulum. Three models are developed. The first one focuses on the behavior of the jig under some simplified assumptions, as a unidirectional and spatially uniform velocity field. This model aims to understand the behavior of the crane with a limited number of parameters. Depending on the shape of the velocity field, the response of the structure is characterized by the variance of the angular position and velocity, the percentage of autorotations, etc. In case of a deterministic and periodic wind velocity, the stability of the jig is represented in the amplitude-frequency parameter space and instability lobes can be highlighted for characteristic frequencies of the sollicitation. The intermediate and complete models raise the assumptions of the first model and define a realistic wind field characterized by its power spectral density. The stochastic process is studied thanks to Monte Carlo simulations. [less ▲]

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See detailrecherche de nouvelles potentialités des bacteries du genre Bacillus pour l'agriculture et l'agroalimentaire
Ait Kaki, Asma ULg

Doctoral thesis (2014)

L’exploration des échantillons en provenance de divers environnements de l’Est Algérien (du lac salé de Ain M’lila et de la rhizosphère d’une plante adjacente ; de l’eau de la source thermale d’Oued El ... [more ▼]

L’exploration des échantillons en provenance de divers environnements de l’Est Algérien (du lac salé de Ain M’lila et de la rhizosphère d’une plante adjacente ; de l’eau de la source thermale d’Oued El-Athmanya et du sol environnant ; de la rhizosphère de la plante Calendula officinalis, cultivée en serre à Setif) a abouti à l’obtention de 39 isolats de Bacillus et de Paenibacillus, dont 28 % sont sélectionnés pour leur capacité à inhiber la croissance de certaines moisissures phytopathogènes comme : Alternaria alternata, Aspergillus niger, Botrytis cinerea, Cladosporium cucumerinium, Fusarium oxysporium et Fusarium sp. Le calcul du taux d’inhibition de la croissance fongique par les isolats sélectionnés, réalisé, à titre d’exemple, sur F. oxysporium et B. cinerea, a permis d’obtenir des valeurs variant entre 39% et 84% suivant l’isolat. L’identification moléculaire des isolats sélectionnés par l’analyse d’ADN-16S et du gène « gyrase-A » a montré que les isolats de Ain M’lila appartiennent à Bacillus amyloliquefaciens, ceux isolés d’Oued El Athmanya sont : B. amyloliquefaciens, B. atrophaeus et B. mojavensis, enfin, les bactéries isolées de la rhizosphère de C. officinalis, sont : Paenibacillus polymyxa, B. velezensis, B. amyloliquefaciens et B. subtilis subsp. spizezenii. Les souches de Bacillus sélectionnées développent, dans les conditions de culture en fioles, des taux de sporulation importants variant entre 8 .108 et 27.108 spores/ml., alors que, le taux de sporulation chez P. polymyxa est insignifiant. Seuls les isolats de B. amyloliquefaciens sont capables de produire de la protéase. Cependant, l’activité cellulasique est observée chez toutes les espèces de Bacillus étudiées exceptant le B. atrophaeus qui a été le seul à produire de la chitinase. Toutes les espèces étudiées ont les mêmes capacités à produire les trois familles de lipopeptides (iturines, fengycines et surfactine), les siderophores et l’indole 3 acide acétique (IAA). Toutefois, le P. polymyxa (18SRTS) produit, dans les conditions expérimentales, une meilleure concentration d’IAA (54µg/ml). Par ailleurs, il est à mettre en exergue que, les B. amyloliquefaciens isolés du lac salé et de la source thermale produisent de nouvelles variantes de fengycines. En effet, il a été mis en évidence que le B. amyloliquefaciens (ET), produit de nouveaux homologues de fengycines A et B, ayant des chaines d’acides gras à 20 et à 18 atomes de carbone, respectivement, et deux nouvelles variantes de fengycines (fengycine X et Y) à cycles peptidiques dont la structure diffère de celle des fengycines conventionnelles. L’activité antifongique de certains isolats (B. amyloliquefaciens (ET), B. atrophaeus (6SEL), B. mojavensis (9SEL), B. amyloliquefaciens (9SRTS) et B. subtilis subsp. spizezenii (23SRTS)) sur milieux gélosés à base d’exsudats racinaires de tomate, de courgette et d’haricot, obtenus à différentes températures a été observée, vis-à-vis d’Alternaria alternata et de F. oxysporium. En complément, les souches B. atrophaeus (6SEL), B. amyloliquefaciens (9SRTS) et B. subtilis sub sp spizezenii (23SRTS), ont fait l’objet d’une production industrielle avec un taux de survie, après lyophilisation, très appréciable et leurs test in situ en serre et en champs sur le pois chiche a révélé une capacité intéressante de biofertilisation, de phytostimulation et de biocontrôle, ce qui justifie largement l’objectif assigné à cette recherche. [less ▲]

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See detailBrûlons (un peu) les business plans !
Dufays, Frédéric ULg

Article for general public (2014)

L’impact du business plan sur la performance de l’entrepreneur est contesté. Souvent considéré comme une obligation, le business plan a-t-il dès lors encore une utilité ? Nous montrons qu'outre sa ... [more ▼]

L’impact du business plan sur la performance de l’entrepreneur est contesté. Souvent considéré comme une obligation, le business plan a-t-il dès lors encore une utilité ? Nous montrons qu'outre sa fonction de support de réflexion pour l'entrepreneur, le business plan constitue un signal pour les parties prenantes (et les investisseurs en particulier), et permet dès lors de construire une légitimité pour l'entrepreneur, qui peut faciliter le processus d'acquisition de ressources. [less ▲]

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See detailAssessing tropical forage species used as pig feed ingredients in the western provinces of the Democratic Republic of the Congo
Kambashi Mutiaka, Bienvenu ULg

Doctoral thesis (2014)

The use of forage species to feed pig goes back to immemorial times. If forage is no longer used in industrial farms with genetically-improved breeds, its accounts for an important part of pig diets in ... [more ▼]

The use of forage species to feed pig goes back to immemorial times. If forage is no longer used in industrial farms with genetically-improved breeds, its accounts for an important part of pig diets in smallholder pig production systems in tropical areas including the Western provinces of the Democratic Republic of the Congo (DRC). The aim of this research thesis was to assess the relevancy of the use of local forage resources as a strategy to reduce reliance of pig production systems on concentrate feed ingredients in tropical environment, by identifying plant species available to smallholders with interesting nutritional value that could partly replace concentrates in the diets. First, smallholder pig production systems in two western provinces of the DRC were characterized and the most used forage species in pigs identified. Their nutritional value was determined using an in vitro model of the pig’s gastro-intestinal tract. It was concluded that Manihot esculenta, Ipomoea batatas, Moringa oleifera, and legume species exhibit an interesting profile for feeding pigs while grasses, Eichhornia crassipes, Acacia mangium and Cajanus cajan should be discouraged. Feeding values of Psophocarpus scandens, Vigna unguiculata, Stylosanthes guianensis, and Pueraria. phaseoloides were measured by assessing the voluntary feed intake of forage hays-based diets and their digestibility. Finally, the economic impact of feeding Psophocarpus scandens, Vigna unguiculata, and Stylosanthes guianensis, was measured through growth performance, carcass quality, and production costs determination. It is concluded that although forage species reduce the nutritive value and the growth of animals, the investigated legumes do not impact negatively the economical balance of concentrate-fed pigs when forage accounts for approx. 10 % of the diet. The ability of some forage species to improve performances of animals fed ill-balanced diets as usually practiced by smallholder farmers in the DRC should be investigated as it is suspected that under less favourable conditions, conclusions on the usefulness of forage legumes in pigs might be more positive [less ▲]

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See detailLa conditionnalité environnementale dans la politique agricole commune. Analyse de l'intégration de la politique de protection de l'environnement au sein de la politique agricole commune
Habran, Maxime ULg

Doctoral thesis (2014)

Pierre angulaire de la construction européenne, la politique agricole commune (PAC) est à l’origine mise en place dans le but d’assurer l’autosuffisance alimentaire de la Communauté européenne. L’objectif ... [more ▼]

Pierre angulaire de la construction européenne, la politique agricole commune (PAC) est à l’origine mise en place dans le but d’assurer l’autosuffisance alimentaire de la Communauté européenne. L’objectif, rapidement atteint, laisse dans son sillage des stocks et excédents considérables ainsi que des dépenses communautaires importantes. Le mode de production agricole basé sur un modèle productiviste montre rapidement ses limites, obligeant les Etats membres à une réorientation de la PAC. Cette politique sera modifiée et réformée à de nombreuses reprises. La reconnaissance de la protection de l’environnement comme politique transversale contraint les Etats membres à l’adapter. D’une politique productiviste, elle devient attentive aux considérations environnementales, intégrant ces dernières dans chacune des réformes, allant même jusqu’à lier l’octroi de paiement au respect de règles essentiellement environnementales. Cette recherche présente la manière dont s’articule la relation entre les deux politiques autour de la notion de conditionnalité environnementale. A travers une étude minutieuse de chaque réforme de la PAC, une analyse de transversalité permet de saisir les enjeux et les motivations de l’intégration environnementale. [less ▲]

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See detailLe gingembre, antiémétique de premier choix dans la pratique officinale
Angenot, Luc ULg

in Pharma-Sphère (2014), 18(195), 30-31

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See detailThe Belgian Tetris: assessing the political impact of metaphors on citizens' perceptions of Belgian federalism
Perrez, Julien ULg; Reuchamps, Min

Conference (2014, June 20)

In the literature, the political impact of metaphors has often been taken for granted from metaphor analysis in political discourse, be it elite discourse or media discourse. However, a more global ... [more ▼]

In the literature, the political impact of metaphors has often been taken for granted from metaphor analysis in political discourse, be it elite discourse or media discourse. However, a more global understanding of what this political impact could consist of, is still lacking from the current research agenda. As Koller (2009:121) puts it: “metaphor helps construct particular aspects of reality and reproduce (or subvert) dominant schemas.” To be able to account for how metaphors, through discourses, actively shape the political reality, it is important to look at the relationships between metaphorical discourses and their environment. Based on the idea that metaphors do not only reflect the perceived reality, but also function as cues through which citizens come to understand complex political processes and through which they shape political behaviors, the aim of this study is precisely to look at how specific metaphors might impact on the citizens’ framing of Belgian federalism. To measure the impact of metaphors on the citizens’ political representations and attitudes, we developed an experimental set-up based on an article published in the Belgian newspaper Le Soir (13-14 July 2013) in which Belgian federalism was deliberately compared to a Tetris game. The original article included a picture and a text (208 words), which were used as authentic experimental material. For this experiment, we distinguished three experimental conditions and one control condition. In the first experimental condition (full condition), the participants were exposed to the original article (including the text and the picture). In the second and third experimental conditions, the participants were respectively exposed either to the text (text condition) or the picture (picture condition). In the control condition, the participants weren’t exposed to any metaphorical material at all. In the second stage of the experiment, the participants were asked to achieve three interrelated tasks: (i) a free description task, based on a free description of their own perception of Belgian federalism, (ii) an association task, in which they had to select a picture which they found the most appropriate to describe Belgian federalism, and finally (iii) a questionnaire measuring the participants’ political knowledge of Belgian federalism and attitudes towards its future development. In a post-test held four weeks after the first experiment, the three tasks of the second stage have been replicated. This experiment has been conducted in autumn 2013 among 400 students. Comparing the various experimental conditions will make it possible (i) to measure the impact of the Tetris metaphor on the citizens’ perceptions and representations of Belgian federalism, (ii) to assess to what extent the different metaphorical media differently contribute to this impact and (iii) to measure the long-term impact of this metaphor on the citizens’ political representations and attitudes. In answering these questions, this study will contribute to a better understanding of the role and functions metaphors play in political discourse, and more globally in our everyday political interactions. [less ▲]

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See detailTriple negative tumors accumulate significantly less methylglyoxal specific adducts than other human breast cancer subtypes
Chiavarina, Barbara ULg; Nokin, Marie-Julie; Durieux, Florence ULg et al

in Oncotarget (2014)

Metabolic syndrome and type 2 diabetes are associated with increased risk of breast cancer development and progression. Methylglyoxal (MG), a glycolysis by- product, is generated through a non-enzymatic ... [more ▼]

Metabolic syndrome and type 2 diabetes are associated with increased risk of breast cancer development and progression. Methylglyoxal (MG), a glycolysis by- product, is generated through a non-enzymatic reaction from triose-phosphate intermediates. This dicarbonyl compound is highly reactive and contributes to the accumulation of advanced glycation end products. In this study, we analyzed the accumulation of Arg-pyrimidine, a MG-arginine adduct, in human breast adenocarcinoma and we observed a consistent increase of Arg-pyrimidine in cancer cells when compared with the non-tumoral counterpart. Further immunohistochemical comparative analysis of breast cancer subtypes revealed that triple negative lesions exhibited low accumulation of Arg-pyrimidine compared with other subtypes. Interestingly, the activity of glyoxalase 1 (Glo-1), an enzyme that detoxifies MG, was significantly higher in triple negative than in other subtype lesions, suggesting that these aggressive tumors are able to develop an efficient response against dicarbonyl stress. Using breast cancer cell lines, we substantiated these clinical observations by showing that, in contrast to triple positive, triple negative cells induced Glo-1 expression and activity in response to MG treatment. This is the first report that Arg- pyrimidine adduct accumulation is a consistent event in human breast cancer with a differential detection between triple negative and other breast cancer subtypes. [less ▲]

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See detailLe français cadien, un français acadien? Enjeux sociaux d’une parenté linguistique
Arrighi, Laurence; Urbain, Emilie ULg

Conference (2014, June 20)

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See detailImprovement of data quality for Diffusion Kurtosis Imaging and application to clinical neurological research
André, Elodie ULg

Doctoral thesis (2014)

Understanding human brain function and dysfunction is one of the major challenges of our century. One of the most popular methods to achieve this goal is in vivo magnetic resonance imaging. In particular ... [more ▼]

Understanding human brain function and dysfunction is one of the major challenges of our century. One of the most popular methods to achieve this goal is in vivo magnetic resonance imaging. In particular, diffusion-weighted (DW) imaging has become a standard tool to non-invasively study white matter structure in vivo. The main contributions of this work can be divided in two parts. The first part deals with the development of pre-processing methods to improve image quality and the accuracy of diffusion tensor and diffusion kurtosis-derived parameters. First, we describe and evaluate a novel method to correct data misalignment due to subject motion. Using an iterative model-based ap- proach, individual diffusion images are realigned to their own theoretical pair, rather than to the unweighted image. A recently developed advanced measure of tensor distance was used as a stopping criterion. The accuracy of the method is tested via a simulated diffusion tensor imaging data set. We have shown here that our procedure is a reliable and efficient way to correct subject motion during DW acquisitions, and that with a proper acquisition setup, it performs better than standard coregistration procedures. Next, we studied the influence of noise in diffusion kurtosis imaging. Two noise correction approaches are proposed and applied to a pool of 25 sub- jects to evaluate inter-subject variability and the impact of noise correc- tion. Additionally, data were acquired on a single subject with different head positions within the coil and different acquisition scheme to evaluate the impact of noise correction on within-subject variability. Results show a strong impact of noise correction on the estimated mean kurtosis, while the estimation of fractional anisotropy and mean diffusivity were less affected. Both within- and between-subject signal-to-noise (SNR) related variability of the mean kurtosis estimate is considerably reduced after correction for the noise bias, leading to more accurate and reproducible measures. In this work, we have proposed a straightforward method that improves the accu- racy of diffusion kurtosis metrics. Diffusion kurtosis imaging acquisitions at higher spatial resolution are made possible, which increases the chances to make valuable inferences in group analysis.The second part of this thesis deals with a clinical application of these meth- ods. A large group of patients with early-stage Parkinson’s disease was in- vestigated with diffusion kurtosis imaging and compared with a group of age- and sex-matched healthy volunteers using voxel-based analysis. Kur- tosis metrics show more sensitivity to white matter changes than standard diffusion metrics. Significant differences were found in posterior cerebral areas as well as subcortical regions like the putamen, and are therefore promising results. [less ▲]

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See detailGrowth of Chlorella in the presence of organic carbon: A photobioreactor study
Miazek, Krystian ULg; Goffin, Dorothée ULg; Richel, Aurore ULg et al

Scientific conference (2014, June 19)

In this study, the effect of organic carbon supplementation at low light intensity on Chlorella sorokiniana growth was evaluated. Addition of 1 g/L of acetate to media gave the highest growth rate and ... [more ▼]

In this study, the effect of organic carbon supplementation at low light intensity on Chlorella sorokiniana growth was evaluated. Addition of 1 g/L of acetate to media gave the highest growth rate and provided stable high biomass culture during prolonged cultivation time. Glucose at 1 – 5 g/L also improved biomass growth rate, although stability of high biomass culture could not be achieved. Overall, the presence of organic carbon can considerably enhance Chlorella growth when low light intensity is applied. [less ▲]

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See detailRésultats et conséquences des élections du 25 mai 2014
Verjans, Pierre ULg

Conference given outside the academic context (2014)

Comparer trois élections qui ont eu lieu le même jour dans quatre entités fédérées différentes entre elles synchroniquement et diachroniquement permet d'avoir une vue d'ensemble des mouvements électoraux ... [more ▼]

Comparer trois élections qui ont eu lieu le même jour dans quatre entités fédérées différentes entre elles synchroniquement et diachroniquement permet d'avoir une vue d'ensemble des mouvements électoraux et de leurs conséquences politiques aux niveaux régionaux, fédéral et européen. [less ▲]

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See detailA wavelet-based analysis of surface air temperature regularity
Deliège, Adrien ULg; Nicolay, Samuel ULg

Conference (2014, June 19)

The aim of the talk is to present the "wavelet transform microscope" and the wavelet leaders method to show that surface air temperature signals of weather stations selected in Europe are monofractal, i.e ... [more ▼]

The aim of the talk is to present the "wavelet transform microscope" and the wavelet leaders method to show that surface air temperature signals of weather stations selected in Europe are monofractal, i.e. all the points have the same Hölder (regularity) exponent. This study reveals that the information obtained in this way are richer than previous works studying long range correlations in meteorological stations. The approach presented here allows to bind the Hölder exponents with the pressure anomalies, and such a link does not exist with methods previously carried out. Moreover, this regularity is a signature of the type of climate the stations are associated to: indeed, it is possible to establish a climate classification of weather stations in Europe which matches the Köppen-Geiger climate classification. A blind test is performed in order to confirm the results, which can be partly explained by the influence of the North Atlantic Oscillation. This result could give rise to new criteria to determine the efficiency of current climatic models. [less ▲]

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See detailAneignung Herrenloser Sachen
Gerkens, Jean-François ULg

Scientific conference (2014, June 19)

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