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See detailBiogeographic variations in wood mice: Testing for the role of morphological variation as a line of least resistance to evolution
Renaud, Sabrina; Quere, Jean Pierre; Michaux, Johan ULg

in Cox, Philippe; Hautier, Lionel (Eds.) Cambridge Studies in Morphology and Molecules: New Paradigms in Evolutionary Biology ‘Evolution of the Rodents: Advances in Phylogeny, Paleontology and Functional Morphology’ (2015)

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See detailCorporate Disclosures, Information Asymmetry and Stock-Market Liquidity in France
Sougné, Danielle ULg; Ajina, Aymen; Lakhal, Faten

in Journal of Applied Business Research (2015), Vol 31(4),

This paper aims at studying the effect of corporate disclosures on information asymmetry and stock-market liquidity in France. Specifically, the purpose of this paper is to highlight the importance of ... [more ▼]

This paper aims at studying the effect of corporate disclosures on information asymmetry and stock-market liquidity in France. Specifically, the purpose of this paper is to highlight the importance of information included in the annual reports on investor’s behavior. This is proxied by the information asymmetry component of the bid-ask spread and stock market liquidity. Our sample includes 196 French listed firms over a period ranging from 2004 to 2007. We opt for an explanatory study using OLS regressions to examine the nature of the relationship between information disclosed in annual reports and bid-ask spreads a proxy for information asymmetry and stock market liquidity. The results show that the extent of corporate disclosures in annual reports positively influences the liquidity of the French market and negatively affects the adverse selection component of the bid-ask spread. This effect is further confirmed by the commitment to IFRS by French-listed firms from 2005. The decomposition of the total score in the sub-indices shows that non-financial and financial information are important in trading decisions while strategic information may be attractive only for long-term positions [less ▲]

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See detailGlucosinolates and by-products in rapeseed meal related to hydrothermal processing
Quinsac, A.; Carré, P.; Fauconnier, Marie-Laure ULg et al

Poster (2015, July)

Background: For safety reasons, rapeseed meal (RSM) is usually desolventized with strong hydrothermal treatments, leading to various levels of residual glucosinolates (GSL), and protein solubility. The ... [more ▼]

Background: For safety reasons, rapeseed meal (RSM) is usually desolventized with strong hydrothermal treatments, leading to various levels of residual glucosinolates (GSL), and protein solubility. The RSM nutritional quality may be then lowered for monogastrics, due to GSL breakdown products whose reliable and “easy to use” indicators lack. [less ▲]

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See detailComparison of experimental results and numerical modelling of unreinforced load-bearing masonry structures subjected to earthquake loading
Mordant, Christophe ULg; Denoël, Vincent ULg; Degée, Hervé

in Proceedings of the SECED 2015 Conference: Earthquake Risk and Engineering towards a Resilient World (2015, July)

This paper presents a comparison of experimental tests results on unreinforced load-bearing masonry structures subjected to earthquake loading with numerical predictions. First, simple walls are submitted ... [more ▼]

This paper presents a comparison of experimental tests results on unreinforced load-bearing masonry structures subjected to earthquake loading with numerical predictions. First, simple walls are submitted to cyclic and shaking table tests. Some of them include soundproofing devices in order to investigate their influence on the general behaviour in static and dynamic conditions. Additional walls with an opening and T-shaped walls are then tested under cyclic loading. The study is focused on the frame effect, the contribution of the perpendicular wall to the global strength and the efficiency of the connection. These aspects are also studied through shaking table tests on two masonry frames with T- or L-shaped piers. The main information is expressed in terms of force-displacement curves, mechanical properties and energy dissipation for the cyclic tests. The shaking table tests provide results in terms of dynamic and mechanical properties. Comparison of the results with numerical predictions is finally performed thanks to the software TREMURI. [less ▲]

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See detailSpectroscopic survey of Kepler stars. I. HERMES/Mercator observations of A- and F-type stars
Niemczura, E.; Murphy, S. J.; Smalley, B. et al

in Monthly Notices of the Royal Astronomical Society (2015), 450

The Kepler space mission provided near-continuous and high-precision photometry of about 207,000 stars, which can be used for asteroseismology. However, for successful seismic modelling it is equally ... [more ▼]

The Kepler space mission provided near-continuous and high-precision photometry of about 207,000 stars, which can be used for asteroseismology. However, for successful seismic modelling it is equally important to have accurate stellar physical parameters. Therefore, supplementary ground-based data are needed. We report the results of the analysis of high-resolution spectroscopic data of A- and F-type stars from the Kepler field, which were obtained with the HERMES spectrograph on the Mercator telescope. We determined spectral types, atmospheric parameters and chemical abundances for a sample of 117 stars. Hydrogen Balmer, Fe I, and Fe II lines were used to derive effective temperatures, surface gravities, and microturbulent velocities. We determined chemical abundances and projected rotational velocities using a spectrum synthesis technique. The atmospheric parameters obtained were compared with those from the Kepler Input Catalogue (KIC), confirming that the KIC effective temperatures are underestimated for A stars. Effective temperatures calculated by spectral energy distribution fitting are in good agreement with those determined from the spectral line analysis. The analysed sample comprises stars with approximately solar chemical abundances, as well as chemically peculiar stars of the Am, Ap, and Lambda Boo types. The distribution of the projected rotational velocity, Vsini, is typical for A and F stars and ranges from 8 to about 280 km/s, with a mean of 134 km/s. [less ▲]

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See detailHölder Continuity and Wavelets
Simons, Laurent ULg

Doctoral thesis (2015)

There exist a lot of continuous nowhere differentiable functions, but these functions do not have the same irregularity. Hölder continuity, and more precisely Hölder exponent, allow to quantify this ... [more ▼]

There exist a lot of continuous nowhere differentiable functions, but these functions do not have the same irregularity. Hölder continuity, and more precisely Hölder exponent, allow to quantify this irregularity. If the Hölder exponent of a function takes several values, the function is said multifractal. In the first part of this thesis, we study in details the regularity and the multifractality of some functions: the Darboux function, the Cantor bijection and a generalization of the Riemann function. The theory of wavelets notably provides a tool to investigate the Hölder continuity of a function. Wavelets also take part in other contexts. In the second part of this thesis, we consider a nonstationary version of the classical theory of wavelets. More precisely, we study the nonstationary orthonormal bases of wavelets and their construction from a nonstationary multiresolution analysis. We also present the nonstationary continuous wavelet transform. For some irregular functions, it is difficult to determine its Hölder exponent at each point. In order to get some information about this one, new function spaces based on wavelet leaders have been introduced. In the third and last part of this thesis, we present these new spaces and their first properties. We also define a natural topology on them and we study some properties. [less ▲]

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See detailTransnational routes for hyper-local practices. Homemade food of Moroccan migrant women in Italy.
Mescoli, Elsa ULg

Conference (2015, June 22)

Stemming from a doctoral research on the culinary practices of a group of Moroccan migrant women living in the north of Italy, this paper will focus on some narratives and habits concerning homemade food ... [more ▼]

Stemming from a doctoral research on the culinary practices of a group of Moroccan migrant women living in the north of Italy, this paper will focus on some narratives and habits concerning homemade food. This food was the result of the combination of hyper-local and transnational practices. In fact, preparing some food at home instead of buying it (bread, for example) was possible also thanks to the use of some ingredients that were bought in or coming from Morocco. The issue at stake was that of control: a control exerted at a hyper-local level (in one’s home) on procedures and at a transnational level (by personally knowing ingredients’ producers) on food elements. This combination let women prepare some representative food of their memory by using the traditional techniques learnt from their mothers and by excluding intermediations. Homemade food translated the reassuring utopia of keeping a link with a cultural belonging in spite of migration and of reducing the fear of being contaminated by the unknown products of the diversity. Some ethnographic data will be presented to show these dynamics, and they will be supported by the visual material collected through participant observation. [less ▲]

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See detailEngager le littéraire : le cas Sartre/Fanon
Cormann, Grégory ULg

Conference (2015, June 20)

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See detailModel polyQ proteins based on the beta-lactamase BlaP: How non-polyQ regions influence the polyQ length-dependent aggregation process
Huynen, Céline ULg

Doctoral thesis (2015)

Neurodegenerative amyloid diseases are fatal disorders representing an important human health and economic burden. Amongst them, nine disorders are classified as polyglutamine (polyQ) diseases, for which ... [more ▼]

Neurodegenerative amyloid diseases are fatal disorders representing an important human health and economic burden. Amongst them, nine disorders are classified as polyglutamine (polyQ) diseases, for which no treatment is yet available. They are all characterized by the pathological expansion of a poly(CAG) sequence, above a specific threshold, within the coding sequence of nine unrelated genes, translated in nine polyQ proteins. The polyQ expansion, the only common point, is the critical determinant for polyQ disease development by triggering protein aggregation into amyloid fibrils. More recent studies however indicate that the protein context modulates the polyQ-induced aggregation process and the disease phenotype. The objectives of my thesis are to deeper investigate the molecular determinants of the complex interplay between the propensity of the polyQ tract to trigger protein aggregation and the modulating role of non-polyQ regions in order to allow the identification of strategies to interfere with the pathological aggregation process. For that purpose, model polyQ proteins, referred to as BlaP-polyQ chimeras, based on the β-lactamase BlaP and polyQ sequences (23 – 79Q) inserted at two positions (197, in between or not unstructured peptides, or 216), are used and their aggregation properties are characterized under several conditions. We first observe that the polyQ length is determinant for BlaP-polyQ chimera aggregation. Indeed, there is a Q-threshold for the aggregation into amyloid fibrils and for fibril elongation. Above this threshold, the aggregation in solution and the elongation rate increase with the length of the polyQ tract, with an exponential rise-to-maximum and a linear regression, respectively, independently of the conformation of the BlaP moiety, and of the position of the polyQ tract within BlaP. Longer polyQ tracts are likely to have a larger conformational flexibility allowing them to more easily adopt an amyloid-aggregation prone conformation. However, the Q-threshold for fibril elongation is much lower than for fibril formation in solution: the polyQ tract requires a larger conformational flexibility to nucleate the formation of fibrils than to elongate them. Secondly, the Q-threshold for fibril formation is lower once the BlaP moiety is unfolded, and BlaP-polyQ chimeras aggregate faster into amyloid fibrils under conditions favoring the unfolding of the BlaP moiety. The native structure of BlaP is likely to impose conformational constraints to moderate and long polyQ tracts that block and decrease, respectively, their propensity to form fibrils. The effects of constraints decrease with the polyQ length. Thirdly, BlaP chimeras with the polyQ tract in position 216 have an increased propensity to trigger the nucleation and the elongation of amyloid fibrils compared to chimeras with the polyQ in position 197. Advanced studies confirm that the propensity of the polyQ tract to aggregate into amyloid fibrils is linked to the conformational flexibility of the polyQ tract, which depends on (i) the polyQ length, (ii) the location of the polyQ tract within BlaP, i.e., a terminal location or embedded within a protein domain, and (iii) the structural properties of the polyQ flanking regions. Finally, we observe that the whole region flanking the polyQ tract in position 197 at its N-terminus has an anti-aggregating property that fully counterbalances the pro-aggregating property of that flanking at the C-terminus. The former imposes strong conformational constraints to the polyQ tract that reduce its conformational flexibility and hence its aggregation propensity. Moreover, these regions are likely to differently affect the solubility of the polyQ protein and hence the driving force for insoluble aggregation. Altogether, our data also suggest that BlaP chimeras aggregate via the commonly described nucleation-dependent polymerization mechanism during which the aggregation is first triggered by polyQ-polyQ interactions, and then a subsequent slight reorganization of the BlaP moiety is required for conversion of aggregates into amyloid fibrils. Based on these results, we should allow the development of therapeutic strategies, targeting specifically the molecular features of the complex interplay between the polyQ and non-polyQ regions during the nucleation and/or elongation of the pathological aggregation of polyQ proteins. [less ▲]

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See detailPourquoi se mobiliser pour la planète rouge?
Stiepen, Arnaud ULg

Conference given outside the academic context (2015)

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See detailDes co-enquêteurs coriaces. Quand l'explicitation du travail de terrain complique les choses
Vangeebergen, Thomas ULg

Conference (2015, June 18)

La souplesse et la plasticité des problématiques abordées sont sans doute parmi les attraits majeurs que peuvent présenter les recherches qualitatives. Cette ouverture à une reconfiguration permanente des ... [more ▼]

La souplesse et la plasticité des problématiques abordées sont sans doute parmi les attraits majeurs que peuvent présenter les recherches qualitatives. Cette ouverture à une reconfiguration permanente des questions de recherches réside (entre autres) dans la place que l'on accorde aux acteurs. Plus que des « informateurs », ceux-ci peuvent participer véritablement à l'enquête, et sont alors en fait à la manoeuvre autant que le chercheur. D'acteurs, ils gagnent alors le statut de co-enquêteur. En nous renvoyant nos propres questions, en les reformulant, en les faisant apparaître sous un angle différent, les acteurs contribuent à (re)dessiner nos recherches. [less ▲]

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See detailCompétition partisane, changement climatique et écologie politique : convergences et conflits sur les thématiques politiques
Piet, Grégory ULg

in Flipo, Fabrice (Ed.) Les actes du Colloque "Penser l'écologie politique" (2015, June 16)

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See detailEtude de la sémaphorine virale codée par le gène A3 de l’herpèsvirus alcélaphin 1
Myster, Françoise

Doctoral thesis (2015)

Among gammaherpesvirus, the Macavirus genus is composed of viruses associated to malignant catarrhal fever (MCF) and other phylogenetically related viruses. MCF is a frequently fatal lymphoproliferative ... [more ▼]

Among gammaherpesvirus, the Macavirus genus is composed of viruses associated to malignant catarrhal fever (MCF) and other phylogenetically related viruses. MCF is a frequently fatal lymphoproliferative disease. Three macaviruses inducing MCF have been entirely sequenced: alcelaphine herpesvirus 2 (AlHV-2), ovine herpesvirus 2 (OvHV-2) and alcelaphine herpesvirus 1 (AlHV-1). Sheep carries OvHV-2 asymptomatically while wildebeest is infected with AlHV-1 without developing any clinical signs or lesions. Both viruses represent the most studied macaviruses. In susceptible ruminants, OvHV-2 and AlHV-1 induce the sheep-associated form and the wildebeest-derived form of MCF (WD-MCF), respectively. Economic consequences of WD-MCF are significant in sub-Saharan Africa. WD-MCF is characterized by the proliferation and infiltration of lymphoblastoid T cells surrounding blood vessels and can be considered as a model for peripheral T cell lymphoma caused by a virus. Rabbits are used as experimental model to study MCF. This species develops clinical signs and lesions that they are indistinguishable from those observed in other susceptible species. Until recently, available data on WD-MCF pathogenesis were limited to the simple description clinical signs and lesions. Recently, it was demonstrated that CD8+ T cells proliferate and that this cellular expansion is associated with a severe increase of the viral load in PBMC and lymphoid organs (Dewals et al., 2008). The cloning of the AlHV-1 genome as an infectious and pathogenic bacterial artificial chromosome (BAC) has greatly facilitated the study of individual gene of AlHV-1 (Dewals et al., 2006). Among herpesviruses, viral semaphorins can only be found in members of the Macavirus genus. OvHV 2 encodes Ov3, and AlHV-2 and AlHV-1 encode A3, both genes encoding a semaphorin homolog. Semaphorins are proteins characterized by a conserved amino-terminal domain, the SEMA domain. The roles of the semaphorins on cytoskeleton dynamics have been widely studied. Viral semaphorins could mediate immune evasion mechanisms or viral dissemination and could be involved in specific properties of macaviruses. The first study of the present thesis was dedicated to the investigation of the pathogenesis of WD-MCF and the role of latency. We investigated the distribution of the AlHV-1 infection in the lesions and demonstrated that the infiltration of CD8+ T cells in different lymphoid and non-lymphoid organs and tissues is directly associated with a non-productive viral infection. The second study focused on the A3 gene of AlHV-1 and its potential functions during WD-MCF. We showed that the A3 gene is expressed during the early phase of the viral infection and encodes a functional semaphorin that was termed AlHV-sema. AlHV-sema was able to induce cell retraction. Despite the observed independent acquisition of pox- and herpesvirus semaphorins, AlHV-sema inhibited phagocytosis by dendritic cells and migration to the draining lymph node through mechanisms similar to poxvirus semaphorin. AlHV-sema could also facilitate viral dissemination or confer immune evasion functions. Next, we investigated whether AlHV-sema could affect WD-MCF induction. We did not observe any effect of the absence of AlHV-sema expression during the development of WD-MCF after rabbit nasal infection. Macaviruses are swine and ruminant gammaherpesviruses responsible for a latent asymptomatic infection in their natural species. The development of MCF in other ruminant susceptible species is due to cross-species transmission. During evolution, the gene selection in susceptible species is certainly reduced due to the fact that these species are dead-end hosts. Thus, it is difficult to address the role of AlHV-1 specific genes in MCF as these genes have evolved in other species. Nevertheless, we brought in this work important insight for our understanding of the pathogenesis of WD-MCF and we identified AlHV-sema as a potential immunoevasion factor. DEWALS B., MYSTER F., PALMEIRA L., GILLET L., ACKERMANN M., VANDERPLASSCHEN A. Ex vivo bioluminescence detection of alcelaphine herpesvirus 1 infection during malignant catarrhal fever. J. Virol., 2011, 85, 6941-6954. MYSTER F., PALMEIRA L., SOREL O., BOUILLENNE F., DEPAUW E., SCHWARTZ-CORNIL I., VANDERPLASSCHEN A., DEWALS B.G. Viral semaphorin inhibits dendritic cell phagocytosis and migration but is not essential for gamma-herpesvirus-induced lymphoproliferation in malignant catarrhal fever. J. Virol., 2015. [less ▲]

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