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See detailLe redoublement scolaire rend-il les élèves plus agressifs? Etude quasi-expérimentale sur le redoublement scolaire en début de secondaire et ses conséquences sur l’agressivité
Mathys, Cécile ULg; Véronneau, Marie-Hélène; Lecocq, Aurélie

Conference (2014, May)

Le taux de redoublement scolaire est particulièrement élevé en Belgique. Bien que ses effets concernant les performances académiques soient régulièrement étudiés, les conséquences du redoublement scolaire ... [more ▼]

Le taux de redoublement scolaire est particulièrement élevé en Belgique. Bien que ses effets concernant les performances académiques soient régulièrement étudiés, les conséquences du redoublement scolaire sur l’adaptation psychosociale des élèves fait encore peu l’objet de recherches rigoureuses, notamment concernant le niveau d’agressivité des élèves qui ont vécu un redoublement. Par ailleurs, l’entrée en enseignement secondaire coïncide avec l’affirmation de nouveaux statuts sociaux pour les élèves et l’agressivité peut être une façon d’établir une hiérarchie au sein des groupes de pairs. L’objectif de cette étude est d’examiner si le redoublement scolaire affecte à court terme le niveau d’agressivité d’élèves se situant au début de leur cursus d’enseignement secondaire. Un protocole quasi-expérimental a été utilisé et deux groupes d’élèves comparables (doublants et promus) ont pu être crées grâce à des scores de propension sur base de 26 variables collectées. Des mesures auto-rapportées et standardisées ont été administrées sur deux semestres et un échantillon de 72 élèves provenant d’un établissement secondaire typique de la Fédération Wallonie-Bruxelles (moy. âge = 12.9 ans, 47.2% de filles, 70% d’origine belge) a été identifié. Des analyses univariées réalisées par SPSS (F (1,67) = 6,98, p = 0,01) révèlent que durant l’année suivant le redoublement scolaire, les élèves ayant doublé ne montrent pas de diminution de leur niveau d’agressivité (t (35) = 0,50, ns), contrairement aux élèves ayant été promus (t (32) = 3,32, p = 0,01). En outre, ces résultats sont significativement « palpables » comme l’indique la taille de l’effet plutôt élevée (d = .64). Ces résultats sont discutés en termes d’implications, notamment concernant l’importance de continuer à maintenir un statut social pour les élèves ayant vécu une expérience de redoublement au début de leur cursus en enseignement secondaire, contrairement aux élèves qui ont été promus. [less ▲]

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See detailGrade retention at the transition to secondary school: A quasi-experimental study of its consequences on relationships with parents and peers
Lecocq, Aurélie; Mathys, Cécile ULg; Véronneau, Marie-Hélène

Conference (2014, May)

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See detailDeterminant of fat mass percentage and absolute fat-free mass in preterm infants at the time of hospital discharge
Simon, Laure; Frondas-Chauty, Anne; SENTERRE, Thibault ULg et al

in American Journal of Clinical Nutrition (2014), 100(1), 98-104

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See detailMicroRNA Targeting of CoREST controls polarization of migrating cortical neurons
Volvert; Prévot, Pierre-Paul; Close, Pierre ULg et al

in Cell Reports (2014), 7(4), 1168-83

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See detailEntre recettes du Soi et recettes de l'Autre. Ethnographie de pratiques culinaires marocaines à Sesto San Giovanni (Milan, Italie)
Mescoli, Elsa ULg

Doctoral thesis (2014)

La thèse porte sur les processus de subjectivation d’un groupe de femmes marocaines résidant dans la ville de Sesto San Giovanni, dans le nord de l’Italie. Elsa Mescoli considère les habitudes ... [more ▼]

La thèse porte sur les processus de subjectivation d’un groupe de femmes marocaines résidant dans la ville de Sesto San Giovanni, dans le nord de l’Italie. Elsa Mescoli considère les habitudes alimentaires et les pratiques culinaires de ces femmes et de leurs familles, facteurs qui agissent dans la construction de soi à plusieurs niveau : celui intime, en contexte domestique ; celui partagé/contesté, en contexte publique. L’étude se situe au croisement entre l’anthropologie de l’alimentation, l’anthropologie de la culture matérielle et l’anthropologie des migrations. En fait, ces processus sont analysés en adoptant une perspective praxéologique, c’est-à-dire en portant l’attention sur la matérialité. La thèse met en évidence les « ingrédients » concrets de la définition de soi des femmes considérées, ainsi que de leurs rapports interpersonnels et « interculturels ». [less ▲]

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See detailMoyens et fins: de Gramsci à Lefort
Mancuso, Eva ULg

Scientific conference (2014, April 30)

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See detailA new analysis of the optical polarisation alignments of quasars
Pelgrims, Vincent ULg

Poster (2014, April 30)

Introduction of a new statistical method dedicated to the analysis of polarisation orientations and presentation of some results of its application to the sample of optical polarisation measurements of ... [more ▼]

Introduction of a new statistical method dedicated to the analysis of polarisation orientations and presentation of some results of its application to the sample of optical polarisation measurements of 355 quasars. [less ▲]

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See detailEstimation and approximation in nonlinear dynamic systems using quasilinearization
Frasso, Gianluca ULg; Jaeger, Jonathan ULg; Lambert, Philippe ULg

E-print/Working paper (2014)

Nonlinear (systems of) ordinary differential equations (ODEs) are common tools in the analysis of complex one-dimensional dynamic systems. In this paper we propose a smoothing approach regularized by a ... [more ▼]

Nonlinear (systems of) ordinary differential equations (ODEs) are common tools in the analysis of complex one-dimensional dynamic systems. In this paper we propose a smoothing approach regularized by a quasilinearized ODE-based penalty in order to approximate the state functions and estimate the parameters defining nonlinear differential systems from noisy data. Within the quasilinearized spline based framework, the estimation process reduces to a conditionally linear problem for the optimization of the spline coefficients. Furthermore, standard ODE compliance parameter(s) selection criteria are easily applicable and conditions on the state function(s) can be eventually imposed using soft or hard constraints. The approach is illustrated on real and simulated data. [less ▲]

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See detailLe cheminement vers un Empire napoléonien (1800-1804)
Genin, Vincent ULg

Conference given outside the academic context (2014)

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See detailRetrieval of HCHO from MAX-DOAS measurements at the high-altitude alpine station of Jungfraujoch (46.5°N, 8.0°E)
Hendrick, François; Fayt, Caroline; Franco, Bruno ULg et al

Conference (2014, April 30)

Formaldehyde (HCHO) plays an important intermediate role in the atmospheric photo-oxidation pathways. It is produced during the oxidation of methane and many non-methane volatile organic compounds (NMVOCs ... [more ▼]

Formaldehyde (HCHO) plays an important intermediate role in the atmospheric photo-oxidation pathways. It is produced during the oxidation of methane and many non-methane volatile organic compounds (NMVOCs) which participate to the formation of tropospheric ozone and secondary organic aerosols. HCHO is also directly released by biomass burning and fossil fuel combustion and to a lesser extent by vegetation. Measuring this species is therefore of major importance for air quality and climate change monitoring. In this presentation, HCHO near-surface concentrations and vertical column densities are retrieved from MAX-DOAS measurements performed at the high-altitude station of Jungfraujoch (3580m asl) in the Swiss Alps from July 2010 till December 2012. Although being most of the time located in the free troposphere, this station can be temporarily affected by pollution events originating from the valley, leading to a local increase of air pollutant concentrations. The capability of the MAX-DOAS technique to retrieve HCHO in such high-altitude location is investigated. The spatial representativeness and the impact of cloud cover on the measurements is also discussed. For verification purpose, our retrievals are compared to collocated FTIR observations, taking into account the difference in vertical resolution between both techniques. Simulations from the 3D-CTM IMAGES are also used to further assess the observed seasonal and diurnal cycles of HCHO surface concentration and vertical column. [less ▲]

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See detailLD-based haplotype encoding scheme with iterative pruning principal component analysis (ipPCA) to retrieve population substructures
Chaichoompu, Kridsadakorn ULg; Fouladi, Ramouna ULg; Wangkumhang, Pongsakorn et al

Poster (2014, April 29)

Objective To identify and differentiate between subpopulations using a rich set of genetic markers, as using reduced sets of genetic markers for these purposes can become challenging, especially when ... [more ▼]

Objective To identify and differentiate between subpopulations using a rich set of genetic markers, as using reduced sets of genetic markers for these purposes can become challenging, especially when similar geographic regions are involved or when spurious patterns are likely to exist. Method Single Nucleotide Polymorphisms (SNPs) are commonly used to capture variations between populations and often genome-wide SNP data are pruned based on linkage disequilibrium (LD) patterns. Notably, haplotype composition and the pattern of LD between markers may vary between larger populations but may also play a role within more confined geographic regions. Indeed, knowledge about haplotypes in unrelated individuals can reveal useful information about genetic ancestry. Here, we use iterative pruning principal component analysis (ipPCA) [1] to identify and characterize subpopulations in an unsupervised way. As input data, either pruned genome-wide SNP data are used (using PLINK 1.9 with the "indep-pairwise" option, window size = 100k, r2 < 0.25) or multilocus haplotype information derived from the genome-wide SNP panel (using BEAGLE 3.3.2 to infer haplotype). These approaches are applied to real-life data from 992 Thai individuals [2]. Result Preliminary results indicate that ipPCA applied to pruned SNP data or ipPCA that explicitly uses multilocus information (haplotypes) give complementary information about population substructure for geographically confined populations such as the Thai samples in this study. Both methods address different aspects of population structure. Detailed simulation studies are needed to identify the optimal scenarios for haplotype-based ipPCA. Conclusion In this work, we propose to combine an LD-based haplotype encoding scheme with the ipPCA machinery to retrieve fine population substructures. Despite the complexities that are associated with haplotype inference, added value can be obtained when the LD structure between SNPs is exploited in the search for relevant population strata. References 1. Intarapanich, A., et al., Iterative pruning PCA improves resolution of highly structured populations. BMC Bioinformatics, 2009. 10: p. 382. 2. Wangkumhang, P., et al., Insight into the peopling of Mainland Southeast Asia from Thai population genetic structure. PLoS One, 2013. 8(11): p. e79522. [less ▲]

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See detailÉtude des Culicoides Latreille (Diptera: Ceratopogonidae) vecteurs d'agents pathogènes: état des lieux des espèces belges, de leurs micro-habitats larvaires et de leurs préférences trophiques
Zimmer, Jean-Yves ULg

Doctoral thesis (2014)

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are the biological vectors of many recently described pathogens in Northern Europe, including the Bluetongue and Schmallenberg viruses ... [more ▼]

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are the biological vectors of many recently described pathogens in Northern Europe, including the Bluetongue and Schmallenberg viruses. These arboviral diseases have led to considerable economic loss in sheep and cattle livestock. However, many uncertainties remain regarding the distribution, biology, and ecology of these vectors. This research project had three main objectives. The first objective was to conduct an inventory of the different Culicoides species on different Belgian farms and on wetlands, using light traps. Many more Culicoides were caught in the vicinity of buildings than in meadows; this finding seemed to be influenced by the density of hosts near the trap and the opening of buildings. The Obsoletus complex was predominant inside buildings and in the meadows of farms; however, the meadows exhibited greater species diversity. The oligotrophic species C. impunctatus, a potential vector of several pathogens, was particularly abundant in peat bogs. The traps that were used herein enabled the identification of three species that have not previously been reported in Belgium, bringing the total number of Belgian species to 52. The second objective was to identify and characterize larval microhabitats of the main Belgian species of Culicoides, and to study the distribution of coprophilous species (C. chiopterus and C. dewulfi) in meadows. Ten Belgian cattle farms were monitored for two consecutive years, and sixteen substrates conducive to the larval development of these biting midges were identified. The most significant finding was that different types of silage residues (e.g., corn, grass, beet pulp, and their combinations) were favourable to the larvae of the two species that compose the Obsoletus complex. A larval microhabitat that is appropriate to these two species was also identified, for the first time, directly inside a barn: specifically, within the dried dung stuck to the barn walls and resulting from the partial removal of used litter. Therefore, Culicoides could complete their life cycle in the vicinity of the stables, which might explain the persistence of the virus from one year to the next despite harsh winters. Influences of the carbon-to-nitrogen ratio, lignin, insoluble fibre, magnesium, and calcium on the presence of larvae were also examined. The third objective was to study the feeding preferences of the species C. obsoletus. This species is prevalent on Belgian farms and has considerable medical and veterinary relevance. Behavioural analyses were performed under field and laboratory conditions, respectively through a flight tunnel containing potential hosts (human, calf, sheep and chicken) and a two-choice olfactometer containing volatile extracts of host skin. The field experiment revealed the preference of C. obsoletus females for large hosts, probably caused by greater emission of carbon dioxide. In contrast, these midges were more attracted to volatile organic compounds released from the skin surface of chicken and sheep during the laboratory experiment. This study contributed to improve the fundamental knowledge of Palaearctic species of the genus Culicoides, and highlighted promising avenues to control these biting midges. Knowledge of the breeding sites of Culicoides could thus allow substrates to be monitored and control or hygiene measures to be implemented, while preventing new sites from being created. A better understanding of the vector-host interactions may aid in developing new strategies to control adult midges, while improving understanding of the pathogen transmission cycle and the epidemiology of associated diseases. [less ▲]

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See detailCode du développement territorial et politique foncière
Fontaine, Pierre; Halleux, Jean-Marie ULg

Conference (2014, April 28)

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See detailMuti-scale methods with strain-softening: damage-enhanced MFH for composite materials and computational homogenization for cellular materials with micro-buckling
Wu, Ling ULg; Nguyen, Van Dung ULg; Doghri, Issam et al

Scientific conference (2014, April 28)

Materials used in the aerospace industry, as composite or foamed materials are multiscale in nature. To predict the macroscopic behaviour of structures made of such materials, the micro-scopic responses ... [more ▼]

Materials used in the aerospace industry, as composite or foamed materials are multiscale in nature. To predict the macroscopic behaviour of structures made of such materials, the micro-scopic responses should also be computed within a nested scheme. This is particularly true when non-linear behaviours are modelled, or when the failure and post failure analyses are sought. In this work, multi-scale methods with strain softening are developed in the contexts of damage modelling for composite laminates and of buckling analyses in cellular materials. First, an anisotropic gradient–enhanced continuum damage model is embedded in a mean–field homogenization (MFH) process for elasto-plastic composites. The homogenization procedure is based on the newly developed incremental secant mean-field homogenization formulation, for which the residual stress and strain states reached in the phases upon a fictitious elastic unloading are considered as starting point to apply the secant method. The mean stress fields in the phases are then computed using isotropic secant tensors, which are naturally used to define the Linear Comparison–Composite The resulting multi– scale model is then applied to study the damage process at the meso–scale of laminates, and in particular the damaging of plies in a composite stack. By using the gradient–enhanced continuum damage model, the problem of losing uniqueness upon strain softening is avoided. Second, an efficient multi–scale finite element framework capturing the buckling instabilities in cellular materials is developed. As a classical multi–scale computational homogenization scheme loses accuracy with the apparition of the macroscopic localizations resulting from the micro–buckling, the second order multi–scale computational homogenization scheme is considered. This second–order computational framework is enhanced with the following novelties so that it can be used for cellular materials. At the microscopic scale, the periodic boundary condition is used because of its efficiency. As the meshes generated from cellular materials exhibit a large void part on the boundaries and are not conforming in general, the classical enforcement based on the matching nodes cannot be applied. A new method based on the polynomial interpolation2 without the requirement of the matching mesh condition on opposite boundaries of the representative volume element (RVE) is developed. Next, in order to solve the underlying macroscopic Mindlin strain gradient continuum of this second–order scheme by the displacement–based finite element framework, the treatment of high order terms is based on the discontinuous Galerkin (DG) method to weakly impose the C1-continuity. Finally, as the instability phenomena are considered at both scales of the cellular materials, the path following technique is adopted to solve both the macroscopic and microscopic problems. [less ▲]

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See detailLong-wave infrared digital holographic interferometry with diffuser or point source illuminations for measuring deformations of aspheric mirrors
Vandenrijt, Jean-François ULg; Thizy, Cédric ULg; Queeckers, Patrick et al

in Optical Engineering : The Journal of the Society of Photo-Optical Instrumentation Engineers (2014), 53(11), 112309

Long-wave infrared digital holographic interferometry with CO2 laser and microbolometer arrays has been developed for testing the large deformations of space reflectors. The setup considered is a ... [more ▼]

Long-wave infrared digital holographic interferometry with CO2 laser and microbolometer arrays has been developed for testing the large deformations of space reflectors. The setup considered is a Mach–Zehnder, associated to the digital holography reconstruction of the wavefront in the inline configuration with phase shifting. Two possibilities exist for illuminating the tested reflector: either with a point source (similarly to classical interferometry) or an extended source (with a diffuser). This paper presents the development of a modular setup which allows comparing both in the case of a parabolic mirror [less ▲]

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See detailTentatives de réflexion sémiotique et psychanalytique au sujet du voile islamique
Demoulin, Laurent ULg

E-print/Working paper (2014)

La sémiotique et la psychanalyse sont peut-être de nature à enrichir le débat sur l'interdiction du voile islamique dans les lieux publics.

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See detailThe age of river-transported carbon: new data from African catchments and a global perspective
Marwick, TR; Tamooh, F; Teodoru, C et al

Conference (2014, April 27)

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