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See detailValidation of ACE-FTS v2.2 methane profiles from the upper troposphere to the lower mesosphere
De Mazière, Martine; Vigouroux, Corinne; Bernath, Peter et al

in Atmospheric Chemistry and Physics (2008), 9(9), 2421-2435

The ACE-FTS (Atmospheric Chemistry Experiment – Fourier Transform Spectrometer) solar occultation instrument that was launched onboard the Canadian SCISAT-1 satellite in August 2003 is measuring vertical ... [more ▼]

The ACE-FTS (Atmospheric Chemistry Experiment – Fourier Transform Spectrometer) solar occultation instrument that was launched onboard the Canadian SCISAT-1 satellite in August 2003 is measuring vertical profiles from the upper troposphere to the lower mesosphere for a large number of atmospheric constituents. Methane is one of the key species. The version v2.2 data of the ACE-FTS CH4 data have been compared to correlative satellite, balloon-borne and ground-based Fourier transform infrared remote sensing data to assess their quality. The comparison results indicate that the accuracy of the data is within 10% in the upper troposphere – lower stratosphere, and within 25% in the middle and higher stratosphere up to the lower mesosphere (<60 km). The observed differences are generally consistent with reported systematic uncertainties. ACE-FTS is also shown to reproduce the variability of methane in the stratosphere and lower mesosphere. [less ▲]

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See detailDétection et caractérisation de peptides obliques au sein de protéines amyloïdogéniques
Crowet, Jean-Marc ULg

Doctoral thesis (2008)

The study of amyloidogenic proteins is of interest in biochemistry because these proteins undergo conformational changes and aggregation. Both processes are largely implicated in several diseases ... [more ▼]

The study of amyloidogenic proteins is of interest in biochemistry because these proteins undergo conformational changes and aggregation. Both processes are largely implicated in several diseases including Alzheimer’s, Parkinson’s or Creutzfeldt-Jakob’s disease. These phenomena are not completely understood, either at a structural or energetical point of view. Tilted peptides are short protein fragment (11 to 19 residues) that adopt a tilted orientation when inserted into biological membranes and destabilise them. Recently, tilted peptides have been detected in two amyloidogenic proteins involved in neurodegenerative diseases; the amyloid β peptide responsible for Alzheimer’s disease, and the PrP protein that causes Creutzfeldt-Jakob’s disease. Tilted peptides could be responsible for the neurotoxic effects of these proteins. Due to their destabilising properties, they could interact directly with the membrane leading to cell death. Tilted peptides could also be involved in the transconformational process of the proteins. The aim of this work is to detect tilted fragments in other amyloidogenic proteins by molecular modelling and to study some of these peptides experimentally to evidence their lipid destabilizing properties, their structure and their toxicity. In addition, this work enable the design of an automatic method of detection for tilted peptides. Twenty-two tilted peptides from 18 different proteins have been detected among 53 amyloidogenic proteins and 7 peptides were tested experimentally. The results support the hypothesis that some tilted peptides could be involved in transconformational processes and/or cytotoxicity related to amyloidogenic proteins. [less ▲]

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See detailDu « Prof de gym » au « Prof d’éducation physique »
Cloes, Marc ULg

Conference given outside the academic context (2008)

La problématique récurrente, c'est la manque d'activité physique chez les jeunes. Une réflexion s'impose en collaboration avec les décideurs politiques, les responsables du sport et de l'éducation pour ... [more ▼]

La problématique récurrente, c'est la manque d'activité physique chez les jeunes. Une réflexion s'impose en collaboration avec les décideurs politiques, les responsables du sport et de l'éducation pour favoriser un style de vie plus actif et ainsi démontrer que l'activité physique, dont fait partie le sport, et la santé sont intimement liés. L'exposé est divisé en deux parties: (1) Jeu de questions/réponses avec quatre témoins privilégiés ayant tous plus de ving années d'expérience et qui travaillent dans des contextes très différents (niveau d'enseignement, réseau, types de populations différentes, quartiers populaires, écoles à discrimination positive); (2) Court exposé plus théorique. [less ▲]

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See detailDas Wildschwein und die geheimnisvolle Insel
Gerkens, Jean-François ULg

Scientific conference (2008, May 06)

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See detailLa régénération des friches industrielles à Liège et à Sheffield
Guilliams, P.; Halleux, Jean-Marie ULg

Conference (2008, May 06)

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See detailL'astronomie dans le monde
Manfroid, Jean ULg

Article for general public (2008)

Rayons cosmiques exceptionnels; Un GRB record; Cassini frôle Encelade; Exoplanètes en transit; Une naine brune très froide; Trou noir intermédiaire; Aminoacétonitrile interstellaire; Aspects cachés de ... [more ▼]

Rayons cosmiques exceptionnels; Un GRB record; Cassini frôle Encelade; Exoplanètes en transit; Une naine brune très froide; Trou noir intermédiaire; Aminoacétonitrile interstellaire; Aspects cachés de Jupiter; N132D; [less ▲]

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See detailTransiting exoplanets from the CoRoT space mission. I. CoRoT-Exo-1b: a low-density short-period planet around a G0V star
Barge, P.; Baglin, A.; Auvergne, M. et al

in Astronomy and Astrophysics (2008), 482

Context: The pioneer space mission for photometric planet searches, CoRoT, steadily monitors about 12 000 stars in each of its fields of view. Transit candidates can be detected early in the processing of ... [more ▼]

Context: The pioneer space mission for photometric planet searches, CoRoT, steadily monitors about 12 000 stars in each of its fields of view. Transit candidates can be detected early in the processing of the data and before the end of a run of observation. Aims: We report the detection of the first planet discovered by CoRoT and characterizing it with the help of follow-up observations. Methods: Raw data were filtered from outliers and residuals at the orbital period of the satellite. The orbital parameters and the radius of the planet were estimated by best fitting the phase folded light curve with 34 successive transits. Doppler measurements with the SOPHIE spectrograph permitted us to secure the detection against binaries and to estimate the mass of the planet. Results: The accuracy of the data is very high with a dispersion in the 2.17 min binned phase-folded light curve that does not exceed ~3.×10[SUP]-4[/SUP] in flux unit. The planet orbits a mildly metal-poor G0V star of magnitude V=13.6 in 1.5 days. The estimated mass and radius of the star are 0.95±0.15 M[SUB]o[/SUB] and 1.11±0.05 R[SUB]o[/SUB]. We find the planet has a radius of 1.49±0.08 R_Jup, a mass of 1.03±0.12 M_Jup, and a particularly low mean density of 0.38±0.05 g cm[SUP]-3[/SUP]. The CoRoT space mission, launched on Dec. 27th, 2006, was developed and is operated by the CNES, with participation of the Science Program of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany and Spain. Based in part on observations with the SOPHIE spectrograph at Obs. de Haute Provence, France. Table [see full text] is only available in electronic form at http://www.aanda.org Individual photometric measurements are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/482/L17 [less ▲]

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See detailTransiting exoplanets from the CoRoT space mission. II. CoRoT-Exo-2b: a transiting planet around an active G star
Alonso, R.; Auvergne, M.; Baglin, A. et al

in Astronomy and Astrophysics (2008), 482

Context: The CoRoT mission, a pioneer in exoplanet searches from space, has completed its first 150 days of continuous observations of ~12 000 stars in the galactic plane. An analysis of the raw data ... [more ▼]

Context: The CoRoT mission, a pioneer in exoplanet searches from space, has completed its first 150 days of continuous observations of ~12 000 stars in the galactic plane. An analysis of the raw data identifies the most promising candidates and triggers the ground-based follow-up. Aims: We report on the discovery of the transiting planet CoRoT-Exo-2b, with a period of 1.743 days, and characterize its main parameters. Methods: We filter the CoRoT raw light curve of cosmic impacts, orbital residuals, and low frequency signals from the star. The folded light curve of 78 transits is fitted to a model to obtain the main parameters. Radial velocity data obtained with the SOPHIE, CORALIE and HARPS spectrographs are combined to characterize the system. The 2.5 min binned phase-folded light curve is affected by the effect of sucessive occultations of stellar active regions by the planet, and the dispersion in the out of transit part reaches a level of 1.09×10[SUP]-4[/SUP] in flux units. Results: We derive a radius for the planet of 1.465 ± 0.029 R_Jup and a mass of 3.31 ± 0.16 M_Jup, corresponding to a density of 1.31 ± 0.04 g/cm^3. The large radius of CoRoT-Exo-2b cannot be explained by current models of evolution of irradiated planets. Based on observations obtained with CoRoT, a space project operated by the French Space Agency, CNES, with participation of the Science Programme of ESA, ESTEC/RSSD, Austria, Belgium, Brazil, Germany and Spain; and on observations made with SOPHIE spectrograph at Observatoire de Haute Provence, France (PNP.07 A.MOUT), CORALIE, and HARPS spectrograph at ESO La Silla Observatroy (079.C-0127/F)). Table 2 is only available in electronic form at http://www.aanda.org [less ▲]

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See detailTransiting exoplanets from the CoRoT space mission. III. The spectroscopic transit of CoRoT-Exo-2b with SOPHIE and HARPS
Bouchy, F.; Queloz, D.; Deleuil, M. et al

in Astronomy and Astrophysics (2008), 482

We report on the spectroscopic transit of the massive hot-Jupiter CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE and HARPS. By modeling the radial velocity anomaly occurring during the ... [more ▼]

We report on the spectroscopic transit of the massive hot-Jupiter CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE and HARPS. By modeling the radial velocity anomaly occurring during the transit due to the Rossiter-McLaughlin (RM) effect, we determine the sky-projected angle between the stellar spin and the planetary orbital axis to be close to zero lambda = 7.2 ± 4.5 deg, and we secure the planetary nature of CoRoT-Exo-2b. We discuss the influence of the stellar activity on the RM modeling. Spectral analysis of the parent star from HARPS spectra are presented. Observations made with SOPHIE spectrograph at Observatoire de Haute Provence, France (PNP.07A.MOUT) and HARPS spectrograph at ESO La Silla Observatory (079.C-0127(F)). The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brasil, ESA, Germany, and Spain. [less ▲]

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See detailLa Convention d'Aarhus garantit-elle le droit à la protection de l'environnement ?
Delnoy, Michel ULg

in Aménagement - Environnement (2008), n° spécial des 30 ans de la revue

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See detailRobotics and neuroscience: A rhythmic interaction
Ronsse, Renaud; Lefèvre, Philippe; Sepulchre, Rodolphe ULg

in Neural Networks (2008), 21(4), 577-583

At the crossing between motor control neuroscience and robotics system theory, the paper presents a rhythmic experiment that is amenable both to handy laboratory implementation and simple mathematical ... [more ▼]

At the crossing between motor control neuroscience and robotics system theory, the paper presents a rhythmic experiment that is amenable both to handy laboratory implementation and simple mathematical modeling. The experiment is based on an impact juggling task, requiring the coordination of two upper-limb effectors and some phase-locking with the trajectories of one or several juggled objects. We describe the experiment, its implementation and the mathematical model used for the analysis. Our underlying research focuses on the role of sensory feedback in rhythmic tasks. In a robotic implementation of our experiment, we study the minimum feedback that is required to achieve robust control. A limited source of feedback, measuring only the impact times, is shown to give promising results. A second field of investigation concerns the human behavior in the same impact juggling task. We study how a variation of the tempo induces a transition between two distinct control strategies with different sensory feedback requirements. Analogies and differences between the robotic and human behaviors are obviously of high relevance in such a flexible setup. [less ▲]

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See detailLe cerveau dans tous ses etats.
Moonen, Gustave ULg; Ansseau, Marc ULg; Scheen, André ULg

in Revue Médicale de Liège (2008), 63(5-6), 229-30

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See detailAlgal blooms: emerging problem for health and sustainable use of surface waters
Wilmotte, Annick ULg; Descy, Jean-Pierre; Vyverman, Wim

Report (2008)

The BBLOOMS project was a two-year program, which was primarily proposed to make a first assessment of the extent of present cyanobacterial blooms in Belgium and of the potential threat for the surface ... [more ▼]

The BBLOOMS project was a two-year program, which was primarily proposed to make a first assessment of the extent of present cyanobacterial blooms in Belgium and of the potential threat for the surface water resources. In this study, we addressed several aspects: (i) the extent and phenology of nuisance blooms in multiple-use Belgian surface waters, (ii) the taxonomic diversity of bloom-forming cyanobacteria, using traditional and genetic tools, (iii) the use of genetic markers to estimate whether the organisms are potentially toxic, (iv) the measurement of toxin concentration in field samples, and (v) the relationship between environmental variables and nuisance blooms in selected water bodies. Most field samples came from 4 reference lakes (Blaarmeersen lake in Flanders and three pre-dam lakes of Eau d’Heure in Wallonia) that were monitored intensively for 2 years. Twenty-three samples were taken for Blaarmeersen, in a continuous manner. Seventy-three samples were studied for the Eau d’Heure complex, but only when proliferations were observed. Additional samples were provided by summer samplings in a series of small lakes in Flanders carried out by the University of Gent. As this was insufficient to obtain a global view of the phenomenon, we have built BLOOMNET, a network of water managers and users, who received information about cyanobacterial blooms and how to collect them for subsequent analysis. The network contributed about forty samples from all regions. [less ▲]

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See detailLearrn-Nett, un réseau pour la formation des enseignants. Une communauté de pratique ?
Lebrun, M.; Deschryver, N.; Charlier, B. et al

in Charnet, Chantal; Ghersi, Claire; Monino, Jean-Louis (Eds.) Le défi de la qualité dans l'enseignement supérieur : vers un changement de paradigme. Actes du XXVe Colloque de l'Association Internationale de Pédagogie Universitaire (AIPU) (2008, May)

Il y a plus de 10 ans, le réseau LEARN-NETT naissait de la rencontre de professeurs en sciences de l’éducation et était financé pendant trois ans, d’abord au niveau belge puis par la Communauté Européenne ... [more ▼]

Il y a plus de 10 ans, le réseau LEARN-NETT naissait de la rencontre de professeurs en sciences de l’éducation et était financé pendant trois ans, d’abord au niveau belge puis par la Communauté Européenne. Leur préoccupation ? Outre la formation aux usages des TIC dans les pratiques de formation, oeuvrer à la qualité de la formation pédagogique des futurs enseignants en les rendant davantage capables de travailler en équipe (apprentissage de la collaboration à distance) et d’assurer leur propre développement professionnel. Un élément particulier ? Le réseau LEARN-NETT est toujours actif. Ce mini-colloque sera décliné en trois parties. (1) Le dispositif pédagogique LEARN-NETT : les lignes de forces restées stables depuis 10 ans et les aspects qui ont évolué en fonction des avancées technopédagogiques. (2) Une des valeurs ajoutées de ce dispositif : la formation des tuteurs. Comment les tuteurs apprennent-ils leur fonction, développent-ils leurs compétences dans ce dispositif ? (3) Les bénéfices pour les différents acteurs de LEARN-NETT (enseignantschercheurs, tuteurs …), les perspectives nouvelles liées aux développements pédagogiques et technologiques, les conditions de survie et de développement d’un tel réseau et l’impact institutionnel d’un tel projet comme catalyseur de l’innovation pédagogique. [less ▲]

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See detailTowards a Two-Tier Internet coordinate system to mitigate the impact of Triangle Inequality Violations
Kaafar, Mohamed Ali ULg; Gueye, Cheikh Ahmadou Bamba ULg; Cantin, François ULg et al

in Lecture Notes in Computer Science (2008, May), 4982

Routing policies or path inflation can give rise to violations of the Triangle Inequality with respect to delay (RTTs) in the Internet. In network coordinate systems, such Triangle Inequality Violations ... [more ▼]

Routing policies or path inflation can give rise to violations of the Triangle Inequality with respect to delay (RTTs) in the Internet. In network coordinate systems, such Triangle Inequality Violations (TIVs) will introduce inaccuracy, as nodes in this particular case could not be embedded into any metric space. In this paper, we consider these TIVs as an inherent and natural property of the Internet; rather than trying to remove them, we consider characterizing them and mitigating their impact on distributed coordinate systems. In a first step, we study TIVs existing in the Internet, using different metrics in order to quantify various levels of TIVs’ severity. Our results show that path lengths do have an effect on the impact of these TIVs. In particular, the shorter the link between any two nodes is, the less severe TIVs involved in are. In a second step, we do leverage our study to reduce the impact of TIVs on coordinate systems. We focus on the particular case of the Vivaldi coordinate system and we explore how TIVs may impact its accuracy and stability. In particular, we observed correlation between the (in)stability and high effective error of nodes’ coordinates with respect to their involvement in TIVs situations. We finally propose a Two-Tier architecture opposed to a flat structure of Vivaldi that do mitigate the effect of TIVs on the distances predictions. [less ▲]

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See detailA way to deal with model-plant mismatch for a reliable diagnosis in transient operation
Borguet, Sébastien ULg; Dewallef, Pierre ULg; Léonard, Olivier ULg

in Journal of Engineering for Gas Turbines & Power (2008), 130(3),

Least-squares health parameter identification techniques, such as the Kalman filter, have been extensively used to solve diagnosis problems. Indeed, such methods give a good estimate provided that the ... [more ▼]

Least-squares health parameter identification techniques, such as the Kalman filter, have been extensively used to solve diagnosis problems. Indeed, such methods give a good estimate provided that the discrepancies between the model prediction and the measurements are Zero-mean, white, Gaussian random variables. In a turbine engine diagnosis, however this assumption does not always hold due to the presence of biases in the model. This is especially true for a transient operation. As a result, the estimated parameters tend to diverge from their actual values, which strongly degrades the diagnosis. The purpose of this contribution is to present a Kalman filter diagnosis tool where the model biases are treated as an additional random measurement error. The new methodology is tested on simulated transient data representative of a current turbofan engine configuration. While relatively simple to implement, the newly developed diagnosis tool exhibits a much better accuracy than the original Kalman filter in the presence of model biases. [less ▲]

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See detail« Usages de l’ordinateur et apports des médias et des TIC en enseignement » : Construction d’un curriculum de cours destiné aux futurs enseignants de la Communauté française de Belgique
Fontaine, Perrine ULg; Denis, Brigitte ULg

in Charnet, Chantal; Ghersi, Claire; Monino, Jean-Louis (Eds.) Actes du XXVe Colloque de l'Association Internationale de Pédagogie Universitaire (AIPU). Le défi de la qualité dans l'enseignement supérieur : vers un changement de paradigme. Thème 2 (2008, May)

L’étude de Feyens (2006) met en évidence une série de problèmes liés à la mise en œuvre du cours « Usages de l’ordinateur et apports des médias et des TIC en enseignement » dans le cadre de la formation ... [more ▼]

L’étude de Feyens (2006) met en évidence une série de problèmes liés à la mise en œuvre du cours « Usages de l’ordinateur et apports des médias et des TIC en enseignement » dans le cadre de la formation de futurs enseignants (instituteurs et professeurs de l’enseignement secondaire inférieur) en Communauté française de Belgique. Par exemple, l’absence de curriculum officiel de formation, pas de titre spécifique requis chez les enseignants en charge de ce cours, … Un des axes du projet HETICE (Hautes Écoles et Technologies de l’Information et de la Communication pour l’Éducation) mené par le Centre de Recherche sur l’Instrumentation, la Formation et l’Apprentissage (CRIFA) de l’Université de Liège s’attelle actuellement à la mise au point d’un tel curriculum, à la formation des enseignants dispensant ce cours et à l’évaluation de son impact sur leurs pratiques de formation. Cet article traite d’une série d’actions entreprises pour développer ce curriculum et de leurs premiers résultats : une analyse des besoins, une contextualisation de la problématique de la formation initiale des futurs enseignants, une réflexion sur les usages et la plus-value des TIC, un sondage sur les pratiques des TIC effectives des enseignants dans leurs activités d’enseignement/apprentissage et l’élaboration d’une première mouture du curriculum tenant compte de différentes facettes et de la triple concordance entre les objectifs poursuivis, les activités d’apprentissage proposées et l’évaluation. [less ▲]

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