References of "2012"
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See detailUpdate on laboratory diagnosis of acute viral gastroenteritis.
HUYNEN, Pascale ULg

Conference (2012, January 12)

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See detailgender issues in ISRD survey
Gavray, Claire ULg

Conference (2012, January 11)

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See detailAbiotic and biotic control of methanol exchanges in a temperate mixed forest
Laffineur, Quentin ULg; Aubinet, Marc ULg; Schoon, N. et al

in Atmospheric Chemistry and Physics (2012), 12

Methanol exchanges over a mixed temperate forest in the Belgian Ardennes were measured for more than one vegetation season using disjunct eddy-covariance by a mass scanning technique and Proton Transfer ... [more ▼]

Methanol exchanges over a mixed temperate forest in the Belgian Ardennes were measured for more than one vegetation season using disjunct eddy-covariance by a mass scanning technique and Proton Transfer Reaction Mass Spectrometry (PTR-MS). Half-hourly methanol fluxes were measured in the range of −0.6 μgm−2 s−1 to 0.6 μgm−2 s−1, and net daily methanol fluxes were generally negative in summer and autumn and positive in spring. On average, the negative fluxes dominated (i.e. the site behaved as a net sink), in contrast to what had been found in previous studies. An original model describing the adsorption/desorption of methanol in water films present in the forest ecosystem and the methanol degradation process was developed. Its calibration, based on field measurements, predicted a mean methanol degradation rate of −0.0074 μgm−2 s−1 and a half lifetime for methanol in water films of 57.4 h. Biogenic emissions dominated the exchange only in spring, with a standard emission factor of 0.76 μgm−2 s−1. The great ability of the model to reproduce the long-term evolution, as well as the diurnal variation of the fluxes, suggests that the adsorption/desorption and degradation processes play an important role in the global methanol budget. This result underlines the need to conduct long-term measurements in order to accurately capture these processes and to better estimate methanol fluxes at the ecosystem scale. [less ▲]

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See detailAuroral evidence of Io's control over the magnetosphere of Jupiter
Bonfond, Bertrand ULg; Grodent, Denis ULg; Gérard, Jean-Claude ULg et al

in Geophysical Research Letters (2012), 39

Contrary to the case of the Earth, the main auroral oval on Jupiter is related to the breakdown of plasma corotation in the middle magnetosphere. Even if the root causes for the main auroral emissions are ... [more ▼]

Contrary to the case of the Earth, the main auroral oval on Jupiter is related to the breakdown of plasma corotation in the middle magnetosphere. Even if the root causes for the main auroral emissions are Io's volcanism and Jupiter's fast rotation, changes in the aurora could be attributed either to these internal factors or to fluctuations of the solar wind. Here we show multiple lines of evidence from the aurora for a major internally-controlled magnetospheric reconfiguration that took place in Spring 2007. Hubble Space Telescope far-UV images show that the main oval continuously expanded over a few months, engulfing the Ganymede footprint on its way. Simultaneously, there was an increased occurrence rate of large equatorward isolated auroral features attributed to injection of depleted flux tubes. Furthermore, the unique disappearance of the Io footprint on 6 June appears to be related to the exceptional equatorward migration of such a feature. The contemporary observation of the spectacular Tvashtar volcanic plume by the New-Horizons probe as well as direct measurement of increased Io plasma torus emissions suggest that these dramatic changes were triggered by Io's volcanic activity. [less ▲]

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See detailGouverner la maternité au Bénin. Les difficiles conditions d'application des politiques sanitaires dans le territoire de la Pendjari
Sambiéni, N'Koué Emmanuel ULg

Doctoral thesis (2012)

The Tanguieta health district, an important component of the Benin health care system, has been experiencing since the decentralization of the system autonomous management of modern health care at all ... [more ▼]

The Tanguieta health district, an important component of the Benin health care system, has been experiencing since the decentralization of the system autonomous management of modern health care at all levels. It is particularly ingenious in generating health care initiatives in favor of mothers engaged in childbirth, with the support of the State and its partners from the health sector. This commitment is officially justified by the critical situation of maternal health indicators, which are high mortality and morbidity rates. The Tanguieta health district is first a socio-cultural entity of remarkable uniqueness compared to other parts of the country, due to its geographical location, its pandjarian cultural identity and its sociopolitical history. On the basis of this very cultural and sociopolitical identity, the district claims its technical and administrative autonomy in the provision of health care. The intellectual curiosity of this socio-anthropological research was to understand how demand and health care for women who want “to give life” are structured and governed in this socio-cultural and medical area. “Maternal habitus” and “gouvernementality” have been at the same time concepts and methodological and epistemological aspects for decoding and analyzing “order” and “progress” in these logical and obstetrical practices. Essentially qualitative, the research was four years long during which I was mostly in the field observing in maternity hospitals and families, and interviewing various stakeholders involved in care. In this area, traditional institutions have been managing childbirth leaving a narrow space for parents to actively participate in the process of birth giving. Modern maternity hospitals are still struggling for the control of health care during and after childbirth. Unfortunately, traditional institutions are weakened by many social influences and therefore are unable to protect adequately childbirth. Consequently, traditional and modern maternity hospitals are still fatal and morbid. Having little knowledge of socio-cultural realities, the state and its maternal health care supervision institutions, are constantly depending on United States agencies and other private partners, providers of ideological and militant strategies. The National Strategy for the Reduction of Maternal and Neonatal Mortality and the Initiative Woman for Woman developed by the Health Ministry and the zonal management team of the Tanguieta health district underscore a missed rendezvous in the scheduled meeting between the users of maternity hospitals and treatment delivery in the planning of health care. All both elaborate plan. The maternity hospital, with its numerous actors in permanent negotiation without consensus, is conflict bound and often turned away from its mission. It is regularly inserting strategies while at the same time evicting its first beneficiaries and putting the health stakes in the background. For Safe Motherhood in traditional and modern spaces, we have to understand how women always engaged in such a morbid and fatal undertaking can strengthen their legitimate situation in the negotiation for obtaining essential and immediate obstetric health care among the cloud of institutions that control them. We have also to study how can traditional obstetric actors convince themselves of obstetric risks. [less ▲]

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See detailHow to optimally load a set of containers into an aircraft
Schyns, Michael ULg; Limbourg, Sabine ULg; Laporte, Gilbert

E-print/Working paper (2012)

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See detailValidation of Analytical Methods
Rozet, Eric ULg; Hubert, Philippe ULg

Scientific conference (2012, January 10)

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See detailMachine learning-based feature ranking: Statistical interpretation and gene network inference
Huynh-Thu, Vân Anh ULg

Doctoral thesis (2012)

Machine learning techniques, and in particular supervised learning methods, are nowadays widely used in bioinformatics. Two prominent applications that we target specifically in this thesis are biomarker ... [more ▼]

Machine learning techniques, and in particular supervised learning methods, are nowadays widely used in bioinformatics. Two prominent applications that we target specifically in this thesis are biomarker discovery and regulatory network inference. These two problems are commonly addressed through the use of feature ranking methods that order the input features of a supervised learning problem from the most to the less relevant for predicting the output. This thesis presents, on the one hand, methodological contributions around machine learning-based feature ranking techniques and on the other hand, more applicative contributions on gene regulatory network inference. Our methodological contributions focus on the problem of selecting truly relevant features from machine learning-based feature rankings. Unlike the p-values returned by univariate tests, relevance scores derived from machine learning techniques to rank the features are usually not statistically interpretable. This lack of interpretability makes the identification of the truly relevant features among the top-ranked ones a very difficult task and hence prevents the wide adoption of these methods by practitioners. Our first contribution in this field concerns a procedure, based on permutation tests, that estimates for each subset of top-ranked features the probability for that subset to contain at least one irrelevant feature (called CER for "conditional error rate"). As a second contribution, we performed a large-scale evaluation of several, existing or novel, procedures, including our CER method, that all replace the original relevance scores with measures that can be interpreted in a statistical way. These procedures, which were assessed on several artificial and real datasets, differ greatly in terms of computing times and the tradeoff they achieve in terms of false positives and false negatives. Our experiments also clearly highlight that using model performance as a criterion for feature selection is often counter-productive. The problem of gene regulatory network inference can be formulated as several feature selection problems, each one aiming at discovering the regulators of one target gene. Within this family of methods, we developed the GENIE3 algorithm that exploits feature rankings derived from tree-based ensemble methods to infer gene networks from steady-state gene expression data. In a second step, we derived two extensions of GENIE3 that aim to infer regulatory networks from other types of data. The first extension exploits expression data provided by time course experiments, while the second extension is related to genetical genomics datasets, which contain expression data together with information about genetic markers. GENIE3 was best performer in the DREAM4 In Silico Multifactorial challenge in 2009 and in the DREAM5 Network Inference challenge in 2010, and its extensions perform very well compared to other methods on several artificial datasets. [less ▲]

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See detailLe travailleur migrant
Pieret, Denis ULg

Conference given outside the academic context (2012)

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See detailPlasmon-Enhanced Sub-Wavelength Laser Ablation: Plasmonic Nanojets
Valev, V.K.; Denkova, D.; Zheng, X. et al

in Advanced Materials (2012), 24

Plasmonic hotspots are regions on the surface of metal nanostructures where light causes very strong oscillation of the electrons. Because electron oscillations constitute an electric current and because ... [more ▼]

Plasmonic hotspots are regions on the surface of metal nanostructures where light causes very strong oscillation of the electrons. Because electron oscillations constitute an electric current and because electric currents heat up the material the same way an electric stove heats up in the kitchen, the plasmonic hotspots are extremely hot. So hot that they can melt the gold in a spot much smaller than the wavelength of light. We were successfully able to demonstrate that this tiny little pool of molten gold can give rise to the smallest nanojets ever observed. [less ▲]

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See detailResearch on crude protein and digestibility of Arnica montana L. using conventional NIR spectrometry and hyperspectral imaging NIR
Dale, Laura ULg; Fernandez, Juan Antonio; Vermeulen, Philippe et al

in Journal of Food, Agriculture & Environment (2012), 10(1), 391-396

Arnica montana L. (AM) is considered a medicinal plant, used as hay in feed ration. The aim of this study is to assess the prediction of protein content and in vitro organic matter digestibility value in ... [more ▼]

Arnica montana L. (AM) is considered a medicinal plant, used as hay in feed ration. The aim of this study is to assess the prediction of protein content and in vitro organic matter digestibility value in grass mixtures containing Arnica montana L., and in a second step to check if these values have a positive or negative influence in the mixtures. Crude protein has been selected because it is one of the most important quality parameters of forages as nutritional element used in animal feeding. The protein is required on a daily basis for maintenance, lactation, growth and reproduction, but is important for agriculture too, because a high content of protein makes it an important source of feed. The digestibility is also important, because it refers to the extent to which a feedstuff is absorbed in the animal body as it passes through an animal’s digestive tract. In this study, the Weende system (the Kjeldahl method) for the protein content, together with the enzymatic technique for digestibility, was applied and used in combination with non-destructive methods, like those based on the Near Infrared Spectroscopy (NIRS) or the Near Infrared Hyperspectral Imaging. Based on NIR imaging system data, the PLS-DA was used to discriminate between the classes with AM and classes without AM, as well as to build a model that could be used to predict the composition of mixtures. More than 99% correct prediction for AM was obtained. The crude protein content of the hay determined by classical method decrease from the type of meadow Agrostis capillaris L. - Festuca rubra L. (15.22%) until to the pure sample of Arnica montana L. (11.19%); however, the digestibility was highest in the pure sample of Arnica montana L. (84.13%) and lowest in samples from the type of meadow Agrostis capillaris L. - Festuca rubra L. (57.18%) or in samples with the participation of Arnica montana L. This study should lead to a more important point, which is to verify whether the medicinal properties of Arnica montana L. can be transferred or not to milk production through the dairy cow feed. [less ▲]

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See detailA convenient route for the dispersion of carbon nanotubes in polymers: Application to the preparation of electromagnetic interference (EMI) absorbers
Thomassin, Jean-Michel ULg; Vuluga, Daniela; Alexandre, Michaël ULg et al

in Polymer (2012), 53(1), 169-174

A new dispersion technique has been implemented which consists in the polymerization of a monomer in the presence of CNTs in a bad solvent of the polymer. During its formation, the polymer precipitates ... [more ▼]

A new dispersion technique has been implemented which consists in the polymerization of a monomer in the presence of CNTs in a bad solvent of the polymer. During its formation, the polymer precipitates and entraps all the CNTs. Thanks to the establishment of a suitable CNTs dispersion, this method promotes much higher electrical conductivity in the resulting nanocomposite than more conventional techniques, i.e. melt-mixing and co-precipitation. Moreover, the quantity of solvent required is much lower than in the co-precipitation method that makes this process industrially viable. One potential application of these nanocomposites has been demonstrated by the preparation of foams using the supercritical CO2 technology that present very high electromagnetic interference (EMI) absorbing properties since more than 90% of the incoming power being absorbed in the foam. [less ▲]

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See detailLower-Order Effects Adjustment in Quantitative Traits Model-Based Multifactor Dimensionality Reduction
Mahachie John, Jestinah ULg; Cattaert, Tom ULg; Van Lishout, François ULg et al

in PLoS ONE (2012)

Identifying gene-gene interactions or gene-environment interactions in studies of human complex diseases remains a big challenge in genetic epidemiology. An additional challenge, often forgotten, is to ... [more ▼]

Identifying gene-gene interactions or gene-environment interactions in studies of human complex diseases remains a big challenge in genetic epidemiology. An additional challenge, often forgotten, is to account for important lower-order genetic effects. These may hamper the identification of genuine epistasis. If lower-order genetic effects contribute to the genetic variance of a trait, identified statistical interactions may simply be due to a signal boost of these effects. In this study, we restrict attention to quantitative traits and bi-allelic SNPs as genetic markers. Moreover, our interaction study focuses on 2- way SNP-SNP interactions. Via simulations, we assess the performance of different corrective measures for lower-order genetic effects in Model-Based Multifactor Dimensionality Reduction epistasis detection, using additive and co-dominant coding schemes. Performance is evaluated in terms of power and familywise error rate. Our simulations indicate that empirical power estimates are reduced with correction of lower-order effects, likewise familywise error rates. Easy-to-use automatic SNP selection procedures, SNP selection based on ‘‘top’’ findings, or SNP selection based on p-value criterion for interesting main effects result in reduced power but also almost zero false positive rates. Always accounting for main effects in the SNP-SNP pair under investigation during Model-Based Multifactor Dimensionality Reduction analysis adequately controls false positive epistasis findings. This is particularly true when adopting a co-dominant corrective coding scheme. In conclusion, automatic search procedures to identify lower-order effects to correct for during epistasis screening should be avoided. The same is true for procedures that adjust for lower-order effects prior to Model-Based Multifactor Dimensionality Reduction and involve using residuals as the new trait. We advocate using ‘‘on-the-fly’’ lower-order effects adjusting when screening for SNP-SNP interactions using Model-Based Multifactor Dimensionality Reduction analysis. [less ▲]

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See detailL’État burkinabè, le “droit à l'éducation” et les enfants au travail
Wouango, Joséphine ULg

Conference (2012, January 05)

« L’enseignement de base est obligatoire pour tous les enfants de six ans à seize ans », ainsi stipule l’article 4 de la Loi d’Orientation de l’Éducation au Burkina Faso. Dans cette communication, nous ... [more ▼]

« L’enseignement de base est obligatoire pour tous les enfants de six ans à seize ans », ainsi stipule l’article 4 de la Loi d’Orientation de l’Éducation au Burkina Faso. Dans cette communication, nous partirons d’une expérience d’offre et de demande scolaire dans une zone rurale du centre-est du Burkina Faso. Nous verrons comment l’école, de par son fonctionnement interne et sa structuration, a transformé l’engouement en désaffection. Cette expérience rurale n’est pas isolée. Elle nous permet ensuite d’interroger le système scolaire burkinabè contemporain : ses curricula, son fonctionnement interne, sa sélection et sa finalité. Enfin, nous examinerons dans quelle mesure cette école-là peut être une alternative au “travail des enfants”, dont l’élimination semble être une priorité politique depuis une quinzaine d’années. La présente communication s’inspire d’une recherche doctorale en cours. [less ▲]

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See detailHow the DNA damage response determines the fate of HTLV-1 Tax-expressing cells
Boxus, Mathieu ULg; Willems, Luc ULg

in Retrovirology (2012), 9(2),

How the Human T lymphotropic virus type 1 (HTLV-1) Tax protein stimulates proliferation while triggering cell cycle arrest and senescence remains puzzling. There is also a debate about the ability of Tax ... [more ▼]

How the Human T lymphotropic virus type 1 (HTLV-1) Tax protein stimulates proliferation while triggering cell cycle arrest and senescence remains puzzling. There is also a debate about the ability of Tax to activate or inhibit the DNA damage response. Here, we comment on these different activities and propose a conceptual rationale for the apparently conflicting observations. [less ▲]

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See detailInteraction of HTLV-1 Tax with minichromosome maintenance proteins accelerates the replication timing program
Boxus, Mathieu ULg; Twizere, Jean-Claude ULg; Legros, Sébastien et al

in Blood (2012), 119

The Tax oncoprotein encoded by the Human T-cell leukemia virus type 1 (HTLV-1) plays a pivotal role in viral persistence and pathogenesis. HTLV-1 infected cells proliferate faster than normal lymphocytes ... [more ▼]

The Tax oncoprotein encoded by the Human T-cell leukemia virus type 1 (HTLV-1) plays a pivotal role in viral persistence and pathogenesis. HTLV-1 infected cells proliferate faster than normal lymphocytes, expand through mitotic division and accumulate genomic lesions. Here, we show that Tax associates with the minichromosome maintenance MCM2-7 helicase complex and localizes to origins of replication. Tax modulates the spatiotemporal program of origin activation and fires supplementary origins at the onset of S phase. Thereby, Tax increases the DNA replication rate, accelerates S phase progression but also generates a replicative stress characterized by the presence of genomic lesions. Mechanistically, Tax favors p300 recruitment and histone hyperacetylation at late replication domains advancing their replication timing in early S phase. [less ▲]

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