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See detailL’interférence de l’ARN (ARNi): un mécanisme fondamental longtemps ignoré
Cornet, Anne ULg

Conference (2006, December 05)

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See detailInterference Fragmentation Functions and Transverse Spin Studies.
Courtoy, Aurore ULg; Bacchetta, Alessandro; Radici, Marco

Conference (2012)

We report on the extraction of dihadron fragmentation functions (DiFF) from the semi- inclusive production of two hadron pairs in back-to-back jets in e+e− annihilation. A nonzero asymmetry in the ... [more ▼]

We report on the extraction of dihadron fragmentation functions (DiFF) from the semi- inclusive production of two hadron pairs in back-to-back jets in e+e− annihilation. A nonzero asymmetry in the correlation of azimuthal orientations of opposite π+π− pairs is related to the transverse polarization of fragmenting quarks through a significant polarized DiFF. A combined analysis of this asymmetry and the spin asymmetry in the SIDIS process ep↑ → e′(π+π−)X has led to the first extraction of the u and d-flavor transversity parton distribution function in the framework of collinear factorization. [less ▲]

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See detailInterference in the light emitted by a single tunneling atom
Martin, John ULg; Braun, Daniel

Poster (2008, July)

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See detailInterférence négative du travail sur la famille et stress au travail : impact du support organisationnel perçu
Hansez, Isabelle ULg; Stinglhamber, Florence; Hanin, Dorothée

in Pettersen, N.; Boudrias, J. S.; Savoie, A. (Eds.) Entre tradition et innovation, comment transformons-nous l'univers de travail? Actes du 15ème congrès de Psychologie du Travail et des Organisations de Langue Française (2008)

Le modèle de Karasek (1979) est l’un des modèles le plus utilisé dans les recherches sur le lien travail-famille et sur le stress professionnel. Parmi les variables qu’il inclut, figurent le support ... [more ▼]

Le modèle de Karasek (1979) est l’un des modèles le plus utilisé dans les recherches sur le lien travail-famille et sur le stress professionnel. Parmi les variables qu’il inclut, figurent le support social du supérieur et des collègues. À notre connaissance, peu d’études ont essayé d’analyser le lien entre l’interférence travail-famille, le stress négatif et d’autres sources de support social tel que le support perçu de l’organisation. Or, en accord avec la méta-analyse de Rhoades & Eisenberger en 2002, nous faisons l’hypothèse que le support organisationnel perçu joue un rôle central dans le lien entre les caractéristiques du travail, l’interférence négative travail-famille et le stress négatif qui en découle. Notre étude s’est réalisée dans un hôpital belge auprès de 266 membres du personnel soignant. Le questionnaire utilisé comprend : le Job Content Questionnaire de Karasek; l’échelle de support organisationnel perçu de Eisenberger (1986), l’échelle d’interférence négative du travail sur la famille (SWING, Geurts, 2004) et le stress négatif (SPPN, Hansez et al., 2004). Il en résulte que le support organisationnel perçu joue un rôle central dans les relations entre certaines caractéristiques du travail, l’interférence négative travail-famille et le stress par le biais d’une double médiation. En outre, l’effet négatif des exigences de travail sur le support organisationnel perçu est modéré par la latitude de décision que les employés peuvent avoir dans leur travail. Les résultats suggèrent qu’introduire le support organisationnel perçu dans des modèles liés aux relations travail-famille enrichirait les deux courants de recherche envisagés dans cette étude. En outre, le type de modèle utilisé dans cette recherche pourrait aussi être appliqué à d’autres types de variables dépendantes (e.g. la performance au travail). [less ▲]

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See detailInterference of a secondary task on procedural learning in children
Lejeune, Caroline ULg; Desmottes, Lise ULg; Catale, Corinne ULg et al

in Belgian Brain Congress 2012: Abstract Book (2012, October 27)

Introduction Procedural learning is generally considered as involving different learning phases, with cognitive resources playing an important role only during the initial learning step. Through repeated ... [more ▼]

Introduction Procedural learning is generally considered as involving different learning phases, with cognitive resources playing an important role only during the initial learning step. Through repeated practice, the skill becomes progressively more automatic and the involvement of controlled cognitive functions is progressively reduced (Anderson, 2000;Doyon and Benali, 2005;Beaunieux et al., 2006). This view has been supported by studies in which the mirror-tracing paradigm was used to evaluate procedural learning, demonstrating the implication of the executive mechanisms in the first phase of perceptuomotor learning (Rouleau, 2002;Brosseau et al., 2007). However, from a developmental perspective, little is known about the progression of learning in procedural tasks, as well as about the role played by the explicit cognitive processes during learning in children. We recently showed that the cognitive mechanisms involved during the procedural task differed between age groups (Lejeune et al., in press). Indeed, we observed that 7-year-old children performed the procedural task in a less controlled fashion than 10-year-olds, who used a more conscious strategy, which permits them to reach better performance levels. The aim of the present study was to confirm the differential implication of explicit mechanisms in procedural learning in children by using a dual-task paradigm. Objective The present study used a dual-task paradigm in order to further investigate the role played by explicit mechanisms during the early and final stages of procedural learning in two ages-groups (7- and 10 year-olds). An auditory interference task was introduced at the beginning and at the end of the procedural learning phase. According to Sun, Merrill, and Peterson (2001), the introduction of an interference task should affect more the explicit processes than the implicit processes, the latter being more automatic. Thus, we predict that performance would be altered by in the dual-task condition only during the first phase of learning, and not during the automation phase. Furthermore, considering that the cognitive mechanisms underlying procedural learning would be different between 7- and 10-year-old children, we predicted that the impact of the dual-task would differ between the two aged-groups: the dual-task condition should affect performance in 10-year-old children but not in the 7-year-old group. Method Seventy-six children were presented with a Mirror Tracing task under single or dual-task conditions. For the Mirror Tracing task, we conformed to the procedure used in previous studies in children (Vicari et al., 2005;Prehn-Kristensen et al., 2009) and we opted for a 5 points star with the double outline of 1 cm. The instruction was to follow the contour of the figure in order to “catch” different picture without leaving the limits of the contour. There were two learning sessions; the task included 10 trials, with a short break (2 min) between trials, and a second 10 trial session was conducted after a one-week delay. In dual-task condition, participants had to perform the procedural learning task while performing at the same time the interference auditory task (which consisted to answer to questions presented continuously). Results Results showed that completion time and accuracy during the mirror tracing task improved with each successive trial in both groups: all children learned the procedural skill regardless of their age and the experimental condition. As predicted, results showed that the impact of the dual-task differed between aged-groups during the first learning phase. While 10-year-old children were significantly slower and less accurate in the dual-task condition than 10-year-old children in the single-task condition, no difference between learning conditions was revealed in the 7-year-old group. Interestingly, at the end of learning (trials 19 and 20), the interference effect had disappeared: there was no impact of the secondary task on procedural performance, whatever the age-group. Discussion In this study, we explored with a dual-task paradigm the role played by explicit mechanisms during the early and final stages of procedural learning in two age-groups (7- and 10 year-olds). During the first learning step, 10-year-old children in the single-task condition used a conscious strategy to perform the task, which permits them to reach better performance levels than 10-year-old children in the dual-task condition (which prevents them from using their controlled cognitive processes). On the contrary, no impact of the interference task was observed in 7-year-old children, who performed the mirror tracing task similarly in the single- and dual-task conditions. This result supports our hypothesis that, in the beginning of a perceptuo-motor learning task, youngest children perform the procedural task in a more implicit fashion comparatively to older children. Thus, while performance of 10-year-old children is congruent with a top-down conception of procedural learning (i.e., performance in the first learning stages would be sustained by high-level explicit mechanisms), this is not the case for youngest children whose explicit mechanisms are not yet mature. So, our results confirm that the involvement of explicit learning mechanisms is not a “necessary condition” for motor skill learning to occur, a point of view supported by the bottom-up skill learning approach which postulates that explicit declarative knowledge is not necessarily associated with procedural skill learning and that the knowledge acquired could be stored in an implicit mode from the beginning of learning (Karmiloff-Smith, 1992;Sun et al., 2001). [less ▲]

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See detailL'interférence virale chez les Alphaherpesvirinae
Meurens, François; Muylkens, Benoît ULg; Schynts, Frédéric et al

in Virologie (2003), 7

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See detailLes interférences analytiques : les anticorps hétérophiles
Cavalier, Etienne ULg

Conference given outside the academic context (2006)

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See detailLes interférences analytiques dans les dosages immunologiques
Cavalier, Etienne ULg

Conference given outside the academic context (2006)

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See detailLes interférences entre le divorce et les pensions de retraite et de survie: le point de la question
Michiels, Olivier ULg

in Divorce : Actualité Juridique, Sociale et Fiscale (2002), 7

L'article examine les conséquences du divorce sur le droit à la pension de retraite et à la pension de survie.

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See detailInterférences entre phonologie et syntaxe en pathologie développementale du langage
Parisse, Christophe; Maillart, Christelle ULg

in Langage et l'Homme (Le) : Recherches Pluridisciplinaires sur le Langage (2006), 41

We compare three theories (pure phonological theory, surface theory, and mapping theory) about language developmental disorders considering that phonological difficulties are the main reason for the ... [more ▼]

We compare three theories (pure phonological theory, surface theory, and mapping theory) about language developmental disorders considering that phonological difficulties are the main reason for the children’s disorders. First, we identified the linguistic parameters (salience, phonological complexity, syntactic complexity, lexical/functional, semantic/syntactic) that are fundamental to these theories. Then we tested the validity of these parameters by testing them against results obtained by SLI children and control children. Nine syntactic categories were tested (determiner, noun, verb, etc.) No theory could fully explain the results obtained. Some linguistic parameters (eg. phonological complexity) are very interesting but fail to explain all results. Some other parameters (eg. salience) turned out to be inadequate to explain the results of French-speaking children. [less ▲]

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See detailInterferogram Stitching applied to the surface metrology of millimeter–wave and micrometer-wave reflectors
Roose, Stéphane ULg

in Slangen, Pierre; Cerruti, Christine (Eds.) Proc. SPIE 6341, Speckle06: Speckles, From Grains to Flowers (2006, September)

This paper addresses the interferometric measurements performed on PLANCK Secondary reflector-Flight Model (SRFM) during the cryo-optical test at the Centre Spatial de Liege in Belgium. It was requested ... [more ▼]

This paper addresses the interferometric measurements performed on PLANCK Secondary reflector-Flight Model (SRFM) during the cryo-optical test at the Centre Spatial de Liege in Belgium. It was requested to measure the changes of the surface figure error (SFE) with respect to the best ellipsoid, between 293 K and 50 K, with a 1 μm RMS accuracy. To achieve this, Infra Red interferometry has been selected and a dedicated thermo mechanical set-up has been constructed. One emphasizes on the solutions adopted to cope with high surface slopes appearing at cryogenic temperature. Indeed, detector resolution has been exploited to resolve high density fringes at the expense of the aperture. A stitching procedure has been implemented to reconstruct the full aperture measurement with success. Test results are presented. [less ▲]

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See detailAn interferometric camera : ESPI and Photorefractivity
Deveuster, Christophe; Georges, Marc ULg

Conference (1998, May 12)

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See detailInterferometric Constraints on Gravity Darkening with Application to the Modeling of Spica A & B
Aufdenberg, J. P.; Ireland, M. J.; Mérand, A. et al

in Hartkopf, W. I.; Guinan, E. F.; Harmanec, P. (Eds.) Binary Stars as Critical Tools & Tests in Contemporary Astrophysics (2007, August 01)

In 2005 we obtained very precise interferometric measurements of the pole-on rapid rotator Vega (A0 V) with the longest baselines of the Center for High Angular Angular Resolution (CHARA) Array and the ... [more ▼]

In 2005 we obtained very precise interferometric measurements of the pole-on rapid rotator Vega (A0 V) with the longest baselines of the Center for High Angular Angular Resolution (CHARA) Array and the Fiber Linked Unit for Optical Recombination (FLUOR). For the analysis of these data, we developed a code for mapping sophisticated PHOENIX model atmospheres on to the surface of rotationally distorted stars described by a Roche-von Zeipel formalism. Given a setof input parameters for a star or binary pair, this code predicts the interferometric visibility, spectral energy distribution and high-resolution line spectrum expected for the system. For the gravity-darkened Vega, our model provides a very good match to the K-band interferometric data, a good match to the spectral energy distribution -- except below 160 nm -- and a rather poor match to weak lines in the high dispersion spectrum where the model appears overly gravity darkened. In 2006, we used the CHARA Array and FLUOR to obtain high precision measurements of the massive, non-eclipsing, double-line spectroscopic binary Spica, a 4-day period system where both components are gravity darkened rapid rotators. These data supplement recent data obtained with the Sydney University Stellar Interferometer. Our study follows the classic 1971 study by Herbison-Evans et al. who resolved Spica as a binary with the Narrabri Intensity Interferometer. We will report on our progress modelling the new interferometric and archival spectroscopic data, with the goal towards better constraining the apsidal constant. [less ▲]

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See detailInterferometric fringes projection system for 3D profilometry and relief investigation
Moreau, Vincent; Laboury, Dimitri ULg; Tilkens, Bernard et al

in Optical Methods for Arts and Archaeology, Proceedings of SPIE, Vol. 5857 (2005)

We present a new 3D full-frame profilometer based on structured laser light projection method. This device takes advantage of the polarization states splitting technique for producing and shifting ... [more ▼]

We present a new 3D full-frame profilometer based on structured laser light projection method. This device takes advantage of the polarization states splitting technique for producing and shifting multiple sinusoidal Young’s interference patterns that are projected on the inspected surface. The principle of the technique is presented and we discuss the advantages of monochromatic light projection method as a mean to overcome ambient lighting for in-situ measurement. Some results that we obtained on objects from the Egyptian Department of the British Museum are presented to demonstrate that 3D laser profilometry is a worthwhile technique for epigraphic investigations where naked-eye inspections fail. [less ▲]

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See detailAn interferometric study of the Fomalhaut inner debris disk II. Keck Nuller mid-infrared observations
Mennesson, B.; Absil, Olivier ULg; Lebreton, J. et al

in Astrophysical Journal (2013), 763

We report on high contrast mid-infrared observations of Fomalhaut obtained with the Keck Interferometer Nuller (KIN) showing a small resolved excess over the level expected from the stellar photosphere ... [more ▼]

We report on high contrast mid-infrared observations of Fomalhaut obtained with the Keck Interferometer Nuller (KIN) showing a small resolved excess over the level expected from the stellar photosphere. The measured null excess has a mean value of 0.35% +/- 0.10% between 8 and 11 microns and increases from 8 to 13 microns. Given the small field of view of the instrument, the source of this marginal excess must be contained within 2AU of Fomalhaut. This result is reminiscent of previous VLTI K-band observations, which implied the presence of a ~ 0.88% excess, and argued that thermal emission from hot dusty grains located within 6 AU from Fomalhaut was the most plausible explanation. Using a parametric 2D radiative transfer code and a Bayesian analysis, we examine different dust disk structures to reproduce both the near and mid-infrared data simultaneously. While not a definitive explanation of the hot excess of Fomalhaut, our model suggests that the most likely inner few AU disk geometry consists of a two-component structure, with two different and spatially distinct grain populations. The 2 to 11 microns data are consistent with an inner hot ring of very small (~ 10 to 300 nm) carbon-rich grains concentrating around 0.1AU. The second dust population consists of larger grains (size of a few microns to a few tens of microns) located further out in a colder region where regular astronomical silicates could survive, with an inner edge around 1AU. From a dynamical point of view, the presence of the inner concentration of sub-micron sized grains is surprising, as such grains should be expelled from the inner planetary system by radiation pressure within only a few years. This could either point to some inordinate replenishment rates (e.g. many grazing comets coming from an outer reservoir) or to the existence of some braking mechanism preventing the grains from moving out. [less ▲]

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See detailAn Interferometric Study of the Fomalhaut Inner Debris Disk. I. Near-Infrared Detection of Hot Dust with VLTI/VINCI
Absil, Olivier ULg; Mennesson, Bertrand; Le Bouquin, Jean-Baptiste et al

in Astrophysical Journal (2009), 704

The innermost parts of dusty debris disks around main-sequence stars are currently poorly known due to the high contrast and small angular separation with their parent stars. Using near-infrared ... [more ▼]

The innermost parts of dusty debris disks around main-sequence stars are currently poorly known due to the high contrast and small angular separation with their parent stars. Using near-infrared interferometry, we aim to detect the signature of hot dust around the nearby A4 V star Fomalhaut, which has already been suggested to harbor a warm dust population in addition to a cold dust ring located at about 140 AU. Archival data obtained with the VINCI instrument at the VLTI are used to study the fringe visibility of the Fomalhaut system at projected baseline lengths ranging from 4 m to 140 m in the K band. A significant visibility deficit is observed at short baselines with respect to the expected visibility of the sole stellar photosphere. This is interpreted as the signature of resolved circumstellar emission, producing a relative flux of 0.88% ± 0.12% with respect to the stellar photosphere. While our interferometric data cannot directly constrain the morphology of the excess emission source, complementary data from the literature allow us to discard an off-axis point-like object as the source of circumstellar emission. We argue that the thermal emission from hot dusty grains located within 6 AU from Fomalhaut is the most plausible explanation for the detected excess. Our study also provides a revised limb-darkened diameter for Fomalhaut (theta_LD = 2.223 ± 0.022 mas), taking into account the effect of the resolved circumstellar emission. Based on observations made with ESO Telescopes at the Paranal Observatory (public VINCI commissioning data). [less ▲]

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See detailAn interferometric study of the Fomalhaut inner debris disk. III. Detailed models of the exozodiacal disk and its origin
Lebreton, J; van Lieshout, R; Augereau, J-C et al

in Astronomy and Astrophysics (2013), 555

Context. Debris disks are thought to be extrasolar analogues to the Solar System planetesimal belts. The star Fomalhaut harbors a cold debris belt at 140AU comparable to the Edgeworth-Kuiper belt, as well ... [more ▼]

Context. Debris disks are thought to be extrasolar analogues to the Solar System planetesimal belts. The star Fomalhaut harbors a cold debris belt at 140AU comparable to the Edgeworth-Kuiper belt, as well as evidence for a warm dust component, unresolved by single-dish telescopes, that is suspected to be a bright analogue to the Solar System's zodiacal dust. Aims. Interferometric observations obtained with the VLTI/VINCI instrument and the Keck Interferometer Nuller have identi fied near- and mid-infrared excesses attributed respectively to hot and warm exozodiacal dust residing in the inner few AU of the Fomalhaut environment. We aim to characterize the properties of this double inner dust belt and to unveil its origin. Methods.We perform parametric modelling of the exozodiacal disk ("exozodi") using the GRaTer radiative transfer code in order to reproduce the interferometric data, complemented by mid- to far-infrared photometric measurements from Spitzer and Herschel. A detailed treatment of sublimation temperatures is introduced to explore the hot population at the size-dependent sublimation rim. We then use an analytical approach to test successively several source mechanisms for the dust and suspected parent bodies. Results. A good fi t to the multi-wavelength data is found by two distinct dust populations: (1) a population of very small (0.01 to 0.5 µ m) and therefore unbound, hot dust grains con ned in a narrow region ( ~0.1 - 0.3 AU) at the sublimation rim of carbonaceous material; (2) a population of bound grains at 2AU that is protected from sublimation and has a larger mass despite its fainter flux level. We propose that the hot dust is produced by the release of small carbon grains following the disruption of dust aggregates that originate from the warm component. A mechanism such as gas braking is required to further con ne the small grains for long enough. In situ dust production could hardly be ensured for the age of the star and we conclude that the observed amount of dust is triggered by intense dynamical activity. Conclusions. Fomalhaut may be representative of exozodis that are currently being surveyed at near and mid-infrared wavelengths worldwide. We propose a framework for reconciling the "hot exozodi phenomenon" with theoretical constraints: the hot component of Fomalhaut is likely the "tip of the iceberg" as it could derive from the more massive, but fainter, warm dust component residing near the ice line. This inner disk exhibits interesting morphology and can be considered a prime target for future exoplanet research. [less ▲]

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See detailInterférométrie de speckle en infrarouge thermique
Vandenrijt, Jean-François ULg; Georges, Marc ULg

in Résumés du Huitième colloque francophone Méthodes et Techniques Optiques pour l'Industrie (2007, November)

L’utilisation de l'interférométrie de speckle (ESPI) sur des objets opaques diffusants à une longueur d’onde de 10 µm en utilisant une caméra thermographique commerciale est présentée pour la première ... [more ▼]

L’utilisation de l'interférométrie de speckle (ESPI) sur des objets opaques diffusants à une longueur d’onde de 10 µm en utilisant une caméra thermographique commerciale est présentée pour la première fois à notre connaissance. L’idée d’utiliser une longueur d’onde plus grande que les longueurs d’onde visibles habituelles est de rendre les mesures de déplacements par des techniques holographiques moins sensibles aux perturbations extérieures. Dans cet article, nous discutons certains aspect particuliers dûs à l’accroissement de la longueur d’onde dans le domaine thermique de 10 µm. Nous montrons ensuite les résultats de mesures de rotations dans le plan d’une plaque métallique. Nous avons utilisé la technique du décalage de phase pour obtenir des mesures quantitatives qui sont corrélées par des mesures menées en parallèle avec un théodolite. [less ▲]

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