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See detailFirst High-Angular Resolution L' Images of the β Pictoris Debris Disc with the VLT / NaCo
Milli, Julien; Mawet, Dimitri; Absil, Olivier ULg et al

in Booth, Mark; Matthews, Brenda; Graham, James (Eds.) Exploring the Formation and Evolution of Planetary Systems (2014, January 01)

Imaging debris discs in the L'-band (3.8 μm) is a difficult task. Quasi-static speckles from imperfect optics prevail below 1'' whereas background emission is the dominant noise source beyond that ... [more ▼]

Imaging debris discs in the L'-band (3.8 μm) is a difficult task. Quasi-static speckles from imperfect optics prevail below 1'' whereas background emission is the dominant noise source beyond that separation and is much larger than at shorter wavelengths. We demonstrate here the potential of the newly commissioned AGPM coronograph on VLT/NaCo combined with advanced star and sky subtraction technique based on Principal Component Analysis, and we analyze the morphology of the β Pictoris disc. [less ▲]

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See detailThe VLTi/PIONIER survey of southern TTauri disks
Anthonioz, F.; Ménard, F.; Pinte, C. et al

in Booth, Mark; Matthews, Brenda; Graham, James (Eds.) Exploring the Formation and Evolution of Planetary Systems (2014, January 01)

Studying the inner regions of protoplanetary disks (1-10 AU) is of importance to understand the formation of planets and the accretion process feeding the forming central star. Herbig AeBe stars are ... [more ▼]

Studying the inner regions of protoplanetary disks (1-10 AU) is of importance to understand the formation of planets and the accretion process feeding the forming central star. Herbig AeBe stars are bright enough to be routinely observed by Near IR interferometers. The data for the fainter T Tauri stars is much more sparse. In this contribution we present the results of our ongoing survey at the VLTI. We used the PIONIER combiner that allows the simultaneous use of 4 telescopes, yielding 6 baselines and 3 independent closure phases at once. PIONIER's integrated optics technology makes it a sensitive instrument. We have observed 22 T Tauri stars so far, the largest survey for T Tauri stars to this date. Our results demonstrate the very significant contribution of an extended component to the interferometric signal. The extended component is different from source to source and the data, with several baselines, offer a way to improve our knowledge of the disk geometry and/or composition. These results validate an earlier study by Pinte et al. 2008 and show that the dust inner radii of T Tauri disks now appear to be in better agreement with the expected position of the dust sublimation radius, contrary to previous claims. [less ▲]

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See detailTime-Resolved X-ray Spectroscopy of the Massive Binary delta Ori
Nichols, Joy S.; Nazé, Yaël ULg; Corcoran, M. F. et al

in American Astronomical Society Meeting Abstracts (2014, January 01)

We have obtained 500 ks of Chandra HETG observations of the massive binary delta Ori (O9.5II+unseen companion), one of the fundamental calibrators of the mass-luminosity-radius relation in the upper HR ... [more ▼]

We have obtained 500 ks of Chandra HETG observations of the massive binary delta Ori (O9.5II+unseen companion), one of the fundamental calibrators of the mass-luminosity-radius relation in the upper HR diagram. The program is intended to map the emission line parameters as the secondary moves through the wind of the primary star. Custom extraction techniques have been developed to create 12 time-resolved 40 ks spectra from these observations, each of which is properly calibrated for time and temperature effects. Emission line fluxes for these time slice spectra are presented, as well as phase analysis of the variability of the fluxes. We discuss the interpretation of the resulting data, such as colliding winds and occultation of various temperature regimes of the primary wind by the secondary. [less ▲]

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See detailThe Delta Ori Very Large Project: X-ray Emission and Stellar Variability
Corcoran, Michael F.; Nichols, J. S.; Moffat, A. F. et al

in American Astronomical Society Meeting Abstracts (2014, January 01)

Delt Ori is the nearest massive, single-lined eclipsing binary (O9. II+OB, $P=5^{d}.7324$). High resolution X-ray spectrometry combined with high-precision photometry from space offers a unique ... [more ▼]

Delt Ori is the nearest massive, single-lined eclipsing binary (O9. II+OB, $P=5^{d}.7324$). High resolution X-ray spectrometry combined with high-precision photometry from space offers a unique opportunity to geometrically measure the dynamics of the shocked gas around the primary star. We summarize our recent campaign of phase-constrained high-resolution X-ray spectra obtained with the CHANDRA/HETGS plus high-precision optical photometry with MOST. These observations provide local measurement of the distribution of the embedded, X-ray emitting shocks in the wind of an O star via radial velocity variations and occultation effects, along with standard $f/i$ ratio diagnostics, and enable us to look for correlations with the broad-band photometric variability. We discuss how these observations can help determine the primary star's clumping-corrected mass loss rate, and resolve critical uncertainties in our understanding of the connection between stellar and mass loss parameters. [less ▲]

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See detailMatter Matters
Farah, Jihad ULg

Article for general public (2014)

This article presents the book Radicals' City, then it investigates in what way Fregonese and Brand's analytical framework could serve as an innovative approach for analyzing middle-eastern cities and the ... [more ▼]

This article presents the book Radicals' City, then it investigates in what way Fregonese and Brand's analytical framework could serve as an innovative approach for analyzing middle-eastern cities and the role their urban environments' materiality plays in their evolution. [less ▲]

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See detailDétermination des propriétés de couches dans le béton à l'aide d'un géoradar commercial à hautes fréquences: approche pic-à-pic et analyse fréquentielle du coefficient de réflexion
Van der Wielen, Audrey ULg; Nguyen, Frédéric ULg; Courard, Luc ULg

in Annales du Bâtiment et des Travaux Publics (2014)

The Ground Penetrating Radar (GPR) is an efficient tool for the non-destructive inspection of concrete structures. It is widely used for the detection of rebars or humid zones or for evaluating the ... [more ▼]

The Ground Penetrating Radar (GPR) is an efficient tool for the non-destructive inspection of concrete structures. It is widely used for the detection of rebars or humid zones or for evaluating the thickness of elements. But when an element contains a thin layer, the radar waves are submitted to multiple reflections on the interfaces and the layer appears in the radargram as a single reflection, whose detailed analysis can allow determining the thickness and the permittivity of the thin layer. Two approaches were considered in this paper. In the first one, the analysis is based on the peak-to-peak reflection amplitude. The second approach uses a frequency analysis of the reflection coefficient, whose amplitude and phase can then be calculated for several frequencies. With this method, the thickness and permittivity of the layer can in theory be simultaneously determined. Both methods were numerically validated through finite difference simulations and experimentally tested on concrete samples containing an air layer of variable thickness. We showed that the frequency analysis allowed to reach a higher precision in the parameters estimation for a limited additional computing cost. The method efficiency depends on the conditions and is optimal for layers with a high permittivity presenting a large contrast with the matrix. [less ▲]

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See detailConsciousness and Unconsciousness: An EEG Perspective
Noirhomme, Quentin ULg; Laureys, Steven ULg

in Clinical EEG and Neuroscience (2014), 45

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See detailA 3400 year lacustrine paleoseismic record from the North Anatolian Fault, Turkey: Implications for bimodal recurrence behavior
Avsar, Ulas; Hubert, Aurelia ULg; De Batist, Marc et al

in Geophysical Research Letters (2014), 41(2), 377-384

High-resolution physical, geochemical, and geochronological analyses on the sedimentary sequence of Yeniçağa Lake, located in a fault-bounded basin along the North Anatolian Fault, reveal fingerprints of ... [more ▼]

High-resolution physical, geochemical, and geochronological analyses on the sedimentary sequence of Yeniçağa Lake, located in a fault-bounded basin along the North Anatolian Fault, reveal fingerprints of paleoearthquakes. A robust sediment chronology, spanning the last 3400 years, is constructed by radiocarbon dating and time-stratigraphical correlation with the precisely dated Sofular Cave speleothem record. Yeniçağa sedimentary sequence contains 11 seismically induced event deposits characterized by siliciclastic-enriched intervals. Some of the event deposits are also associated with implications of sudden lake deepening, which may be related to coseismic subsidence. The paleoearthquake series having an average recurrence interval of ca. 260 years are interrupted by two possible seismic gaps of ca. 420 and 540 years. [less ▲]

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See detailCharacterization of Lactobacillus strains isolated from Algerian children faeces for their probiotic properties
Bahri, F.; Lejeune, Annick ULg; Dubois-Dauphin, R. et al

in African Journal of Microbiology Research [=AJMR] (2014), 8(3), 297-303

Lactic acid bacteria termed probiotics have preventive as well as curative effects on several types of diarrhoea of different aetiologies. The main objective of this study was to screen lactobacilli ... [more ▼]

Lactic acid bacteria termed probiotics have preventive as well as curative effects on several types of diarrhoea of different aetiologies. The main objective of this study was to screen lactobacilli strains having probiotic traits, isolated from Algerian healthy children faeces on the purpose of using them further in children diarrheal illnesses. One hundred and twenty (120) lactic acid bacteria isolates were selected from faecal samples of healthy Algerian children aged between five and ten years. Gram positive rods and catalase negative bacteria (52 isolates) were screened, in vitro, for their probiotic potential properties including ability to survive in simulated gastro-intestinal conditions, adherence to Caco-2 cells and their antimicrobial activity. The results show that only five strains resisted in simulated gastric juice at pH 1.5 and pepsin. Four of them were resistant to simulated intestinal conditions at pH 8 and pancreatin and have a good adherence. In the end, three of them were retained as they display interesting probiotic profiles characterized by a strong antimicrobial effect against some intestinal pathogenic bacteria. They were identified by 16S rDNA sequencing as Lactobacillus plantarum F12, Lactobacillus brevis G6 and Lactobacillus paracasei B13. [less ▲]

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See detailLa totalité en science et en art
Dondero, Maria Giulia ULg

in Dondero, Maria Giulia; Beyaert-Geslin, Anne (Eds.) Arts et sciences. Approches sémiotiques et philosophiques des images (2014)

Mon étude vise à explorer la notion de totalité en sciences mathématiques et en art afin d’éclaircir le rôle de la perception dans les deux domaines. J’aborderai dans un premier temps la conception de ... [more ▼]

Mon étude vise à explorer la notion de totalité en sciences mathématiques et en art afin d’éclaircir le rôle de la perception dans les deux domaines. J’aborderai dans un premier temps la conception de démonstration visuelle en réfléchissant sur les notions d’hypoicône et de diagramme selon la philosophie mathématique de C.S. Peirce, pour ensuite tester ces notions dans un autre champ, celui des oeuvres d’art (peinture, sculpture, art environnemental). Si dans l’art comme dans les mathématiques, chaque trait appartenant à une configuration visuelle participe d’une totalité et doit occuper la bonne place pour que la totalité puisse fonctionner en tant que telle, la différence est que la totalité est démontable et répétable en mathématiques tandis que dans l’art pictural elle est normalement considérée comme définitive, unique et sacralisée a priori. Dans cet article j'étudie également de formes de totalité plus complexes (sculpture et art environnemental) où la totalité est à construire a posteriori. [less ▲]

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See detailComment les futurs enseignants du secondaire conçoivent-ils l’évaluation formative et ses difficultés de mise en œuvre ?
Goffin, Christelle ULg; Renson, Jean-Marie ULg; Fagnant, Annick ULg

Conference (2014, January)

Plusieurs études portant sur les conceptions relatives à l’évaluation montrent que la fonction formative de l’évaluation semble présente chez la plupart des enseignants du primaire et du secondaire ... [more ▼]

Plusieurs études portant sur les conceptions relatives à l’évaluation montrent que la fonction formative de l’évaluation semble présente chez la plupart des enseignants du primaire et du secondaire. L’étude présentée ici s’appuie sur une analyse de contenu réalisée auprès de 66 futurs enseignants qui se destinent au secondaire supérieur (grades 10-12) en Belgique francophone. Il leur a été demandé d’expliquer pourquoi il est considéré que l’évaluation fait partie intégrante de l’enseignement / apprentissage. Hormis un étudiant, tous font référence aux fonctions de diagnostic et / ou de régulation de l’évaluation. Mais seuls 11 étudiants mentionnent l’idée de régulation interactive. Enfin, une majorité d’étudiants anticipent des difficultés quant à la conception et la correction des évaluations, avec un pourcentage relativement plus élevé d’étudiants fréquentant une section littéraire (versus section scientifique). [less ▲]

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See detailPolitique budgétaire et décision politique: gérer un système fédéral complexe
Piron, Damien ULg

in Revue Nouvelle (2014), 69(1), 61-71

En Belgique, la décision politique repose depuis la fin du XIXème siècle sur le modèle consociatif: des compromis sont conclus entre les "piliers" issus des clivages philosophique et économique. L ... [more ▼]

En Belgique, la décision politique repose depuis la fin du XIXème siècle sur le modèle consociatif: des compromis sont conclus entre les "piliers" issus des clivages philosophique et économique. L'intégration européenne et la fédéralisation redessinent néanmoins cette méthode de gouvernement, ainsi que le montre la comparaison des politiques d'assainissement des finances publiques conduites par les gouvernements Dehaene Ier et Di Rupo. Le modèle fédéral engendre en effet une multiplication du nombre d'acteurs impliqués dans la prise de décision, ce qui complique l'élaboration de compromis. Il appartient donc aux acteurs politiques de maintenir le système belge gouvernable en imaginant des procédures adaptées à cette nouvelle réalité. [less ▲]

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See detailIsolation of an amylolytic chrysophyte, Poterioochromonas sp. from the digestive tract of the termite R. santonensis
Tarayre, Cédric ULg; Bauwens, Julien ULg; Brasseur, Catherine ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18(1),

The aim of this work was the isolation and cultivation of amylolytic protists living in the digestive tract of the termite Reticulitermes santonensis (Feytaud). A chrysophyte identified as ... [more ▼]

The aim of this work was the isolation and cultivation of amylolytic protists living in the digestive tract of the termite Reticulitermes santonensis (Feytaud). A chrysophyte identified as Poterioochromonas sp. was isolated in a special medium containing rice grains as a source of carbon and nitrogen. Then, the protist was grown in a medium containing starch as a carbon source, tryptone, and a phosphate buffer at different pH values (5, 6 and 7). Yeast extract was added or not. Ciprofloxacin was used to avoid the bacterial development. Other antibiotics were also tested but showed an inhibitive effect on the growth of Poterioochromonas sp. Yeast extract allowed reaching 1.9 (pH 5), 2.3 (pH 6) and 2.2 (pH 7) times higher final cell concentrations, and 2.8 (pH 5), 2.8 (pH 6) and 2.2 (pH 7) times higher biomass yields. The starch concentration did not decrease in the medium until 3 and 4 days of culture, with and without yeast extract, respectively. Eight days of culture were necessary for hydrolyzing the starch completely, with and without yeast extract. Maltose and maltotriose were detected in the culture media and were hydrolyzed progressively. Maximal maltose concentrations were 0.68, 0.66 and 0.51 g.l-1 in the medium containing yeast extract. Maltotriose concentrations were only 0.17, 0.14 and 0.12 g.l-1. Other glucose oligomers were also detected but in lower quantities. It was determined that the protist developed a weak amylase activity, particularly at a weakly acidic pH (5-6). Such a pH also allowed a better growth of the protist. A maximal amylase activity of 112 nkat.l-1 was measured with yeast extract at pH 5. No other enzymatic activity (protease, cellulase or xylanase) was detected except amylase. The degradation products of starch which were obtained by enzymatic hydrolysis allow the identification of α-amylase, amyloglucosidase and possibly β-amylase activities. [less ▲]

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See detailImprove the characterization of tropical forests to improve management: policy brief
Gourlet-Fleury, Sylvie; Aleman, Julie; Bayol, Nicolas et al

Report (2014)

CoForChange has shown that management plans based on timber stock recovery are not enough to ensure the sustainability of these production forests. The variability of forest characteristics and their ... [more ▼]

CoForChange has shown that management plans based on timber stock recovery are not enough to ensure the sustainability of these production forests. The variability of forest characteristics and their different responses to disturbance should be considered in management decisions. [less ▲]

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See detailLa voix n'est pas infatigable
Tréger, Isabelle; Remacle, Angélique ULg

in L'Orthophoniste (2014), 335

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See detailAutomated analysis of background EEG and reactivity during therapeutic hypothermia in comatose patients after cardiac arrest
Noirhomme, Quentin ULg; Lehembre, Rémy; Lugo, Zulay et al

in Clinical EEG and Neuroscience : Official Journal of the EEG and Clinical Neuroscience Society (ENCS) (2014)

Visual analysis of electroencephalography (EEG) background and reactivity during therapeutic hypothermia provides important outcome information, but is time-consuming and not always consistent between ... [more ▼]

Visual analysis of electroencephalography (EEG) background and reactivity during therapeutic hypothermia provides important outcome information, but is time-consuming and not always consistent between reviewers. Automated EEG analysis may help quantify the brain damage. Forty-six comatose patients in therapeutic hypothermia, after cardiac arrest, were included in the study. EEG background was quantified with burst-suppression ratio (BSR) and approximate entropy, both used to monitor anesthesia. Reactivity was detected through change in the power spectrum of signal before and after stimulation. Automatic results obtained almost perfect agreement (discontinuity) to substantial agreement (background reactivity) with a visual score from EEG-certified neurologists. Burst-suppression ratio was more suited to distinguish continuous EEG background from burst-suppression than approximate entropy in this specific population. Automatic EEG background and reactivity measures were significantly related to good and poor outcome. We conclude that quantitative EEG measurements can provide promising information regarding current state of the patient and clinical outcome, but further work is needed before routine application in a clinical setting. [less ▲]

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