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See detailCoRoT's view on variable B8/9 stars: spots versus pulsations. Evidence for differential rotation in HD 174648
Degroote, P.; Acke, B.; Samadi, R. et al

in Astronomy and Astrophysics (2011), 536

Context. There exist few variability studies of stars in the region in the Hertzsprung-Russell diagram between the A and B-star pulsational instability strips. With the aid of the high precision ... [more ▼]

Context. There exist few variability studies of stars in the region in the Hertzsprung-Russell diagram between the A and B-star pulsational instability strips. With the aid of the high precision continuous measurements of the CoRoT space satellite, low amplitudes are more easily detected, making a study of this neglected region worthwhile. <BR /> Aims: We collected a small sample of B stars observed by CoRoT to determine the origin of the different types of variability observed. <BR /> Methods: We combine literature photometry and spectroscopy to measure the fundamental parameters of the stars in the sample, and compare asteroseismic modelling of the light curves with (differentially rotating) spotted star models. <BR /> Results: We found strong evidence for the existence of spots and differential rotation in HD 174648, and formulated hypotheses for their origin. We show that the distinction between pulsations and rotational modulation is difficult to make solely based on the light curve, especially in slowly rotating stars. The CoRoT space mission was developed and is operated by the French space agency CNES, with participation of ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany, and Spain.Based on observations made with the ESO telescopes at La Silla Observatory under the ESO Large Programme LP182.D-0356.Based on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.Appendix A is available in electronic form at <A href="http://www.aanda.org">http://www.aanda.org</A> [less ▲]

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See detailCOSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses. IX. Time delays, lens dynamics and baryonic fraction in HE 0435-1223
Courbin, F.; Chantry, Virginie ULg; Revaz, Y. et al

in Astronomy and Astrophysics (2011), 536

We present accurate time delays for the quadruply imaged quasar HE 0435-1223. The delays were measured from 575 independent photometric points obtained in the R-band between January 2004 and March 2010 ... [more ▼]

We present accurate time delays for the quadruply imaged quasar HE 0435-1223. The delays were measured from 575 independent photometric points obtained in the R-band between January 2004 and March 2010. With seven years of data, we clearly show that quasar image A is affected by strong microlensing variations and that the time delays are best expressed relative to quasar image B. We measured ΔtBC = 7.8 ± 0.8 days, ΔtBD = -6.5 ± 0.7 days and ΔtCD = -14.3 ± 0.8 days. We spacially deconvolved HST NICMOS2 F160W images to derive accurate astrometry of the quasar images and to infer the light profile of the lensing galaxy. We combined these images with a stellar population fitting of a deep VLT spectrum of the lensing galaxy to estimate the baryonic fraction, fb, in the Einstein radius. We measured fb = 0.65-0.10+0.13 if the lensing galaxy has a Salpeter IMF and fb = 0.45-0.07+0.04 if it has a Kroupa IMF. The spectrum also allowed us to estimate the velocity dispersion of the lensing galaxy, σap = 222 ± 34 km s-1. We used fb and σap to constrain an analytical model of the lensing galaxy composed of an Hernquist plus generalized NFW profile. We solved the Jeans equations numerically for the model and explored the parameter space under the additional requirement that the model must predict the correct astrometry for the quasar images. Given the current error bars on fb and σap, we did not constrain H0 yet with high accuracy, i.e., we found a broad range of models with χ2 < 1. However, narrowing this range is possible, provided a better velocity dispersion measurement becomes available. In addition, increasing the depth of the current HST imaging data of HE 0435-1223 will allow us to combine ourconstraints with lens reconstruction techniques that make use of the full Einstein ring that is visible in this object. Based on observations made with the 1.2 m Euler Swiss Telescope, the 1.5 m telescope of Maidanak Observatory in Uzbekistan, and with the 1.2 m Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. The NASA/ESA Hubble Space Telescope data was obtained from the data archive at the Space Telescope Science Institute, which is operated by AURA, the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS-5-26555.Light curves are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/536/A53 [less ▲]

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See detailIntroduction
Delfosse, Annick ULg

Conference (2011, December 01)

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See detailLa pensée "cycle de vie" au cœur des démarches d'éco-conception des procédés
Léonard, Angélique ULg

Conference (2011, December 01)

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See detailA multi-epoch XMM-Newton campaign on the core of the massive Cygnus OB2 association
Rauw, Grégor ULg

in Astronomy and Astrophysics (2011), 536

Context. Cyg OB2 is one of the most massive associations of O-type stars in our Galaxy. Despite the large interstellar reddening towards Cyg OB2, many studies, spanning a wide range of wavelengths, have ... [more ▼]

Context. Cyg OB2 is one of the most massive associations of O-type stars in our Galaxy. Despite the large interstellar reddening towards Cyg OB2, many studies, spanning a wide range of wavelengths, have been conducted to more clearly understand this association. X-ray observations provide a powerful tool to overcome the effect of interstellar absorption and study the most energetic processes associated with the stars in Cyg OB2. <BR /> Aims: We analyse XMM-Newton data to investigate the X-ray and UV properties of massive O-type stars as well as low-mass pre-main sequence stars in Cyg OB2. <BR /> Methods: We obtained six XMM-Newton observations of the core of Cyg OB2. In our analysis, we pay particular attention to the variability of the X-ray bright OB stars, especially the luminous blue variable candidate Cyg OB2 #12. <BR /> Results: We find that X-ray variability is quite common among the stars in Cyg OB2. Whilst short-term variations are restricted mostly to low-mass pre-main sequence stars, one third of the OB stars display long-term variations. The X-ray flux of Cyg OB2 #12 varies by 37%, over timescales from days to years, whilst its mean log L[SUB]X[/SUB]/L[SUB]bol[/SUB] amounts to - 6.10. <BR /> Conclusions: These properties suggest that Cyg OB2 #12 is either an interacting-wind system or displays a magnetically confined wind. Two other X-ray bright O-type stars (MT91 516 and CPR2002 A11) display variations that suggest they are interacting wind binary systems. Based on observations collected with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).Full Table 2 and Table 4 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/536/A31">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/536/A31</A> [less ▲]

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See detailTransiting exoplanets from the CoRoT space mission - XIX. CoRoT-23b: a dense hot Jupiter on an eccentric orbit
Rouan, D.; Parviainen, H.; Moutou, C. et al

in Astronomy and Astrophysics (2011), 537

We report the detection of CoRoT-23b, a hot Jupiter transiting in front of its host star with a period of 3.6314 \pm 0.0001 days. This planet was discovered thanks to photometric data secured with the ... [more ▼]

We report the detection of CoRoT-23b, a hot Jupiter transiting in front of its host star with a period of 3.6314 \pm 0.0001 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite, combined with spectroscopic radial velocity (RV) measurements. A photometric search for possible background eclipsing binaries conducted at CFHT and OGS concluded with a very low risk of false positives. The usual techniques of combining RV and transit data simultaneously were used to derive stellar and planetary parameters. The planet has a mass of Mp = 2.8 \pm 0.3 MJup, a radius of Rpl = 1.05 \pm 0.13 RJup, a density of \approx 3 g cm-3. RV data also clearly reveal a non zero eccentricity of e = 0.16 \pm 0.02. The planet orbits a mature G0 main sequence star of V =15.5 mag, with a mass M\star = 1.14 \pm 0.08 M\odot, a radius R\star = 1. 61 \pm 0.18 R\odot and quasi-solar abundances. The age of the system is evaluated to be 7 Gyr, not far from the transition to subgiant, in agreement with the rather large stellar radius. The two features of a significant eccentricity of the orbit and of a fairly high density are fairly uncommon for a hot Jupiter. The high density is, however, consistent with a model of contraction of a planet at this mass, given the age of the system. On the other hand, at such an age, circularization is expected to be completed. In fact, we show that for this planetary mass and orbital distance, any initial eccentricity should not totally vanish after 7 Gyr, as long as the tidal quality factor Qp is more than a few 105, a value that is the lower bound of the usually expected range. Even if Corot-23b features a density and an eccentricity that are atypical of a hot Jupiter, it is thus not an enigmatic object. [less ▲]

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See detailLa production de biohydrogène à partir de substrats carbohydratés : état de l'art
Hiligsmann, Serge ULg; Beckers, Laurent ULg; Masset, Julien ULg et al

in Récents progrès en génie des procédés (2011, December 01)

Hydrogen is being considered as an ideal and clean energy carrier. The recent advances to produce biohydrogen from renewable sources such as biomass and particularly by fermentation of carbohydrate-rich ... [more ▼]

Hydrogen is being considered as an ideal and clean energy carrier. The recent advances to produce biohydrogen from renewable sources such as biomass and particularly by fermentation of carbohydrate-rich substrates from agriculture and agro-industries appear promising. Such a process enables both organic waste treatment and renewable energy production to be coupled. The paper presents the state of the art about the different hydrogen-producing microorganisms and the parameters that have been investigated in order to improve the hydrogen production yields and rates. [less ▲]

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See detailSprache und Dialekt in der Euregio Maas-Rhein
Vromans, Joseph ULg

Scientific conference (2011, December 01)

The Meuse-Rhine Euregion (the Region of Aachen, the German-speaking Community of Belgium, the Belgian Province of Liège, the Belgian Province of Limburg and the southern part of the Dutch Province of ... [more ▼]

The Meuse-Rhine Euregion (the Region of Aachen, the German-speaking Community of Belgium, the Belgian Province of Liège, the Belgian Province of Limburg and the southern part of the Dutch Province of Limburg) is an interesting area from a linguistic point of view: the official languages of the three countries in in the Euregion are Dutch (in Belgium and the Netherlands), French (in Belgium) and German (in Belgium and Germany); regional languages / dialects are Limburgish (which is recognised as a regional language in Dutch Limburg), Ripuarian and Walloon. [less ▲]

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See detailChronique bibliographique - Supplément 2000-2004
Veymiers, Richard ULg; Bricault, Laurent; Budischovsky, Marie-Christine et al

in Veymiers, Richard; Bricault, Laurent (Eds.) Bibliotheca Isiaca II (2011)

Chronique bibliographique qui, sur le modèle de "l’Inventaire Bibliographique des Isiaca" (IBIS), publié dans les "ÉPRO" entre 1972 et 1991, recense, avec un commentaire critique, les publications ... [more ▼]

Chronique bibliographique qui, sur le modèle de "l’Inventaire Bibliographique des Isiaca" (IBIS), publié dans les "ÉPRO" entre 1972 et 1991, recense, avec un commentaire critique, les publications touchant aux cultes isiaques entre 2000 et 2004. [less ▲]

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See detailLa doble historia de "El convidado de papel"
Ceballos Viro, Alvaro ULg

in Revista de Literatura (2011), 73(146), 595-622

This article sets out to question the textual history of _El convidado de papel_, a novel by Benjamín Jarnés. The differences between the two firsts editions of this novel, published in 1928 and 1935, are ... [more ▼]

This article sets out to question the textual history of _El convidado de papel_, a novel by Benjamín Jarnés. The differences between the two firsts editions of this novel, published in 1928 and 1935, are more complex than has hitherto been assumed. They also allow to reconstruct a different plot from the one that can be found in literary histories. In its original version, _El convidado de papel_ was not only a peculiar _Bildungsroman_, but also a typical _doppelgänger_ narrative. Therefore, it contained a dense web of intertextual references which Jarnés deliberately eliminated in the second edition of the novel. These intertextual references stimulate the search for new sources as well as the re-evaluation of the precise mode of influence attributed to familiar sources. [less ▲]

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See detailComparison of bovine and human O26 EHEC strains by the Whole Genome PCR Scanning
Bardiau, Marjorie ULg; Ogura, Y.; Mainil, Jacques ULg et al

Conference (2011, December)

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See detailValorisation de la Carte Numérique des Sols de Wallonie et d’une base de données disponible en analyse de sols, dans le cadre de l’évaluation du risque de pollution des eaux souterraines par les pesticides
Bah, Boubacar Billo ULg; Vanclooster, Marnik; Oger, Robert ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(S2), 709-726

This study shows how the Digital Soil Map of Wallonia and the associated soil database Aardewerk can be combined with the MetaPEARL model to assess the sensitivity of agricultural soils to pesticide ... [more ▼]

This study shows how the Digital Soil Map of Wallonia and the associated soil database Aardewerk can be combined with the MetaPEARL model to assess the sensitivity of agricultural soils to pesticide transfer into underground water tables in Wallonia (Southern Belgium). MetaPEARL is based on an analytical expression which describes the concentration of leached pesticides at the soil profile bottom depending on available data on soil characteristics, climate and pesticide properties. The results show an important soil sensitivity to pesticide transfer with a coefficient of retention on organic matter (Kom) very weak (about 10 dm3.kg-1) or with a relatively high half-life time (DT50 about 60 days). In this case, the pesticide is weakly retained by soil organic matter or slowly degraded and then stays available in the soil and can be quickly leached during rainfalls. In other respects, the pesticide sensitivity to leaching is strongly correlated with soil texture and its organic matter content. It is also observed that the concentration of leached pesticide is strongly depending of the rainfall surplus (water flux into the soil or hydrous balance). A sensitivity analysis has shown that the model is very sensitive to soil thickness, to organic matter content, to the bulk density of the mineral fraction by textural classes and of the organic matter. Therefore, these pedological variables have to be assessed with the highest precision to avoid adding further uncertainty to the predictions obtained. On the basis of the most sensitive soil variables, the analysis of “spatial” uncertainty related to the results delivered by MetaPEARL, due to the consideration of an unique representative value by soil type and by region (deterministic approach), shows that this approach tends to under-estimate the concentration of pesticide leached in the soil. And that compared to the use of a stochastic simulation (probabilistic approach) which takes into account the soil characteristic variability within a given soil type. This stochastic approach allows also the calculation of a more relevant threshold of risk probability (percentile) which can be compared to an imposed standard in view to enhance a sustainable management of natural resources. [less ▲]

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See detailFormation initiale des enseignants à l'éveil scientifique: comment en faire une occasion d'apprentissage pour tous?
Beckers, Jacqueline ULg; Simons, Germain; Crahay, Marcel ULg et al

in Beckers, Jacqueline; Crahay, Marcel (Eds.) Approche par compétences et réduction des inégalités d'apprentissage entre élèves : de l'analyse des situations scolaires à la formation de enseignants (2011)

L'approche par compétences en sciences prônée par le décret nécessite de travailler la démarche scientifique en classe de façon complète : poser une question, formuler une hypothèse, chercher des ... [more ▼]

L'approche par compétences en sciences prônée par le décret nécessite de travailler la démarche scientifique en classe de façon complète : poser une question, formuler une hypothèse, chercher des résultats, expérimentaux ou non, exploiter ces résultats et conclure provisoirement. Cette façon de travailler est complexe et la façon dont l'enseignant va mettre en oeuvre les choses peut engendrer ou non des inégalités d'un élève à l'autre. Cet article est le récit d'une formation initiale d'enseignants du primaire. [less ▲]

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See detailLes conditions de vie extrêmes sur la planète et exobiologie
Cayol, Jean-Luc; Ollivier, Bernard; Alazard, Didier et al

in Bertrand, Jean-Claude; Caumette, Pierre; Lebaron, Philippe (Eds.) et al Ecologie microbienne (2011)

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See detailGuide destiné à la formation d’animateurs pour les « animations pédagogiques »
Schiffers, Bruno ULg; Gilson, Julien; Prunier, Emmanuelle et al

Book published by édité par le COLEACP (2011)

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See detailL'identité wallonne aujourd'hui
Jacquemain, Marc ULg

in Germain, P.; Robaye, R. (Eds.) L'Etat de la Wallonie. Portrait d'un pays et de ses habitants (2011)

L'article fait le point sur le sentiment d'appartenance à la Wallonie et comment il a évolué au sein de la population au sein des quinze dernières années. Il remet en évidence la complémentarité naturelle ... [more ▼]

L'article fait le point sur le sentiment d'appartenance à la Wallonie et comment il a évolué au sein de la population au sein des quinze dernières années. Il remet en évidence la complémentarité naturelle entre le sentiment belge et le sentiment wallon. Il montre que le sentiment d'appartenance est évolutif, qu'il dépend non seulement de l'actualité mais des stratégies d'acteurs politique, économiques ou médiatiques. Il fait aussi l'hypothèse que l'identité wallonne, en terme de contenus, se définit davantage par un modèle socio-économique partagé que par des symboles et qu'elle ne présente donc pas de caractère d'identité nationale. [less ▲]

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See detailLarge-Scale Fire Test of Unprotected Cellular Beam Acting in Membrane Action
Vassart, Olivier; Bailey, C. G.; Hawes, M. et al

in Journal of Structural Fire Engineering (2011), 2(4), 259-268

This paper describes a full scale fire test performed the 27th of February 2010 on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in ... [more ▼]

This paper describes a full scale fire test performed the 27th of February 2010 on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in the central part of the floor are made of cellular beams. The natural fire was created by a wood crib fire load of 700 MJ/m2 and the 9 × 15 m floor survived the fire that peaked at 1000°C and lasted for 90 minutes. Blind predictions of the air temperature development by the software OZone and of the structural behaviour by the software SAFIR which proved quite satisfactory are also described. [less ▲]

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See detailEvaluation of organic dust components cytotoxicity on thp1 monocytes-derived-macrophages using high content analysis
Ramery, Eve ULg; O'Brien, Peter James

in Veterinary Clinical Pathology (2011, December), 40(4), 583

Background: Organic dust contains pathogen associated molecular patterns (PAMPs) which can induce, following chronic exposure, significant airway diseases. Mononuclear phagocytes are key protecting cells ... [more ▼]

Background: Organic dust contains pathogen associated molecular patterns (PAMPs) which can induce, following chronic exposure, significant airway diseases. Mononuclear phagocytes are key protecting cells of the respiratory tract. Several studies have investigated the effects of PAMPs, and mainly endotoxins, on cytokine production. However the sub-lethal cytotoxicity of organic dust components on macrophages has not been tested yet. The novel technology of high content analysis (HCA) is already used to assess subclinical drug-induced toxicity. It combines the capabilities of flow cytometry, intracellular fluorescence probes, and image analysis and enables to perform rapid multiple analysis in large numbers of samples. Objectives: The purpose of the present study was, by using HCA, to investigate the cytotoxicity of the 3 major PAMPs contained in organic dust, ie. endotoxin (LPS), peptidoglycan (PGN) and β-glucans (zymosan) on THP-1 monocyte-derived macrophages. Methods: LPS was used at concentrations of 0.005, 0.01, 0.02, 0.05, 0.1 and 1 μg/ml; PGN and zymosan were used at concentrations of 1, 5, 10, 50, 100 and 500 μg/ml. Cells were exposed to PAMPs for 24 hours. In addition, the oxidative burst and the phagocytic capabilities of the cells were tested. Results: An overlap between PGN intrinsic fluorescence and red/far-red fluorescent dyes occurred, rendering the evaluation of some parameters impossible for PGN. LPS induced sub-lethal cytotoxicity at the lowest dose (from 10 ng/ml). However, the most spectacular changes occurred with zymosan. In addition, zymosan, but not LPS, induced phagosome maturation and oxidative burst. Conclusions: Given the fact that β-glucans can be up to 100 fold more concentrated in organic dust than LPS, these results suggest that β-glucans could play a major role in macrophages impairment following heavy dust exposure and will deserve further investigation in the near future. [less ▲]

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See detailRelaxation schemes for min max generalization in deterministic batch mode reinforcement learning
Fonteneau, Raphaël ULg; Ernst, Damien ULg; Boigelot, Bernard ULg et al

in 4th International NIPS Workshop on Optimization for Machine Learning (OPT 2011) (2011, December)

We study the min max optimization problem introduced in [Fonteneau, 2011] for computing policies for batch mode reinforcement learning in a deterministic setting. This problem is NP-hard. We focus on the ... [more ▼]

We study the min max optimization problem introduced in [Fonteneau, 2011] for computing policies for batch mode reinforcement learning in a deterministic setting. This problem is NP-hard. We focus on the two-stage case for which we provide two relaxation schemes. The first relaxation scheme works by dropping some constraints in order to obtain a problem that is solvable in polynomial time. The second relaxation scheme, based on a Lagrangian relaxation where all constraints are dualized, leads to a conic quadratic programming problem. Both relaxation schemes are shown to provide better results than those given in [Fonteneau, 2011]. [less ▲]

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See detailLotze en Amérique. Le renouveau réaliste en philosophie chez Santayana
Boccaccini, Federico ULg

Conference (2011, December)

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