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See detailThe neon content of nearby B-type stars and its implications for the solar model problem
Morel, Thierry ULg; Butler, K.

in Astronomy and Astrophysics (2008), 487

The recent downward revision of the solar photospheric abundances now leads to severe inconsistencies between the theoretical predictions for the internal structure of the Sun and the results of ... [more ▼]

The recent downward revision of the solar photospheric abundances now leads to severe inconsistencies between the theoretical predictions for the internal structure of the Sun and the results of helioseismology. There have been claims that the solar neon abundance may be underestimated and that an increase in this poorly-known quantity could alleviate (or even completely solve) this problem. Early-type stars in the solar neighbourhood are well-suited to testing this hypothesis because they are the only stellar objects whose absolute neon abundance can be derived from the direct analysis of photospheric lines. Here we present a fully homogeneous NLTE abundance study of the optical Ne I and Ne II lines in a sample of 18 nearby, early B-type stars, which suggests log É (Ne) = 7.97 ± 0.07 dex (on the scale in which log É [H] = 12) for the present-day neon abundance of the local interstellar medium (ISM). Chemical evolution models of the Galaxy only predict a very small enrichment of the nearby interstellar gas in neon over the past 4.6 Gyr, implying that our estimate should be representative of the Sun at birth. Although higher by about 35% than the new recommended solar abundance, such a value appears insufficient by itself to restore the past agreement between the solar models and the helioseismological constraints. Appendices A and B are only available in electronic form at http://www.aanda.org Table [see full text] is also 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/487/307 [less ▲]

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See detailVariation of delta(9)-desaturase activity in dairy cattle
Soyeurt, Hélène ULg; Dehareng, Frédéric; Mayeres, Patrick et al

in Journal of Dairy Science (2008), 91(8), 3211-3224

The endogenous production of unsaturated fatty acids (FA), particularly some monounsaturated FA (%MONO) and nearly all conjugated linoleic acids, is regulated by the 9-desaturase activity. The aims of ... [more ▼]

The endogenous production of unsaturated fatty acids (FA), particularly some monounsaturated FA (%MONO) and nearly all conjugated linoleic acids, is regulated by the 9-desaturase activity. The aims of this study were to assess the variation of this enzymatic activity within lactation, across dairy breeds, and to estimate its genetic parameters. The ratios of C14:1 cis-9 to C14:0, C16:1 cis-9 to C16:0, and C18:1 cis to C18:0 were calculated from FA contents predicted by mid-infrared spectrometry. Variance components and standard errors were estimated using average information REML. The multitrait mixed model included as fixed effects herd × test date × class of lactation number, class of days in milk × class of lactation number, class of age × class of lactation number, and regressions on breed composition. Four random effects were also included: animal genetic effect, 2 permanent environments (within and across lactations), and residual effect. Under the assumption that the calculated ratios are an approximate measurement of 9-desaturase activity, this study showed different sources of variation for this enzymatic activity. A slight difference was observed within lactation. The ratios of C14:1 cis-9 to C14:0 and C16:1 cis-9 to C16:0 increased as a function of days in milk. Differences across 7 dairy breeds were observed. The values of 9-desaturase indices observed for Jersey and Brown-Swiss cows were lower compared with Holstein. The opposite was observed for dual-purpose Belgian Blue cows. Values of heritability for the ratios of C14:1 cis-9 to C14:0, C16:1 cis-9 to C16:0, and C18:1 cis to C18:0 were 20, 20, and 3%, respectively. Negative genetic correlations observed between fat or protein contents and the 3 indices suggested that an increased activity of 9-desaturase could inhibit the synthesis of fat and protein in bovine milk. Negative correlations were also observed between fat or protein contents and the contents of 3 studied unsaturated FA in milk fat (C14:1 cis-9, C16:1 cis-9, and C18:1 cis). The positive genetic correlations observed between %MONO and the ratios of C14:1 cis-9 to C14:0 (0.72), C16:1 cis-9 to C16:0 (0.62), and C18:1 cis to C18:0 (0.97) showed that %MONO is linked to the 9-desaturase activity. [less ▲]

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See detailThe first orbital solution for the massive colliding-wind binary HD 93162 (=WR 25)
Gamen, R.; Gosset, Eric ULg; Morrell, N. I. et al

in Revista Mexicana de Astronomia y Astrofisica Conference Series (2008, August 01)

Since the discovery, with EINSTEIN, of strong X-ray emission associated with HD 93162, this object was recurrently predicted by some authors to be a colliding-wind binary system. However, radial-velocity ... [more ▼]

Since the discovery, with EINSTEIN, of strong X-ray emission associated with HD 93162, this object was recurrently predicted by some authors to be a colliding-wind binary system. However, radial-velocity variations that would prove the suspected binary nature have never been found so far. We spectroscopically monitored this object in order to investigate its possible variability and to provide an answer to the above-mentioned discordance. We derived radial velocities from spectroscopic data acquired mainly between 1994 and 2006, and searched for periodicities. For the first time, periodic radial-velocity variations are detected. Our analysis definitively shows that the Wolf-Rayet star WR 25 is actually an eccentric binary system with a probable period of about 208 days. [less ▲]

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See detailTowards an Understanding of the Of?p star HD 191612: Optical Spectroscopy
Howarth, I. D.; Walborn, N. R.; Lennon, D. J. et al

in Revista Mexicana de Astronomia y Astrofisica Conference Series (2008, August 01)

We have acquired extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and HeI lines show strongly variable emission which is extremely reproducible on a ... [more ▼]

We have acquired extensive optical spectroscopy of the early-type magnetic star HD 191612 (O6.5f?pe-O8fp). The Balmer and HeI lines show strongly variable emission which is extremely reproducible on a well-determined 538-d period. Metal lines and HeII absorptions (including many selective emission lines, but excluding HeII lambda 4686 Å emission) are nearly constant in line strength, but are variable in velocity. The radial-velocity variations establish a double-lined binary orbit with P_{orb} = 1542d, e = 0.44; by elimination, rotational modulation of a magnetically constrained plasma is left as by far the most likely `clock' underlying the 538-d changes. The implied rotation period shows that slow rotators can easily be hidden in the O-star population, with gaussian-like `turbulence' dominating the line widths. [less ▲]

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See detailGravitational Lensing, Dark Matter and the Optical Gravitational Lens Experiment
Surdej, Jean ULg; Claeskens, Jean-François ULg; Delacroix, Christian ULg et al

in Matagne, N.; Cugnon, Joseph; Lansberg, Jean-Philippe (Eds.) American Institute of Physics Conference Proc. Volume 1038 (2008, August 01)

After briefly reviewing the history of gravitational lensing, we recall the basic principles of the theory. We then describe and use a simple optical gravitational lens experiment which has the virtue of ... [more ▼]

After briefly reviewing the history of gravitational lensing, we recall the basic principles of the theory. We then describe and use a simple optical gravitational lens experiment which has the virtue of accounting for all types of image configurations observed so far among the presently known gravitational lens systems. Finally, we briefly present the 4m International Liquid Mirror Telescope project in the context of a photometric monitoring of multiply imaged quasars. [less ▲]

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See detailA transiting planet among 23 new near-threshold candidates from the OGLE survey - OGLE-TR-182
Pont, F.; Tamuz, O.; Udalski, A. et al

in Astronomy and Astrophysics (2008), 487

By re-processing the data of the second season of the OGLE survey for planetary transits and adding new mesurements on the same fields gathered in subsequent years with the OGLE telescope, we have ... [more ▼]

By re-processing the data of the second season of the OGLE survey for planetary transits and adding new mesurements on the same fields gathered in subsequent years with the OGLE telescope, we have identified 23 new transit candidates, recorded as OGLE-TR-178 to OGLE-TR-200. We studied the nature of these objects with the FLAMES/UVES multi-fiber spectrograph on the VLT. One of the candidates, OGLE-TR-182, was confirmed as a transiting gas giant planet on a 4-day orbit. We characterised it with further observations using the FORS1 camera and UVES spectrograph on the VLT. OGLE-TR-182b is a typical ``hot Jupiter'' with an orbital period of 3.98 days, a mass of 1.01 ± 0.15~M_Jup and a radius of 1.13[SUP]+0.24[/SUP][SUB]-0.08[/SUB]~R_Jup. Confirming this transiting planet required a large investment in telescope time with the best instruments available, and we comment on the difficulty of the confirmation process for transiting planets in the OGLE survey. We delineate the zone were confirmation is difficult or impossible, and discuss the implications for the CoRoT space mission in its quest for transiting telluric planets. Based on observations made with the FORS1 camera and the FLAMES/UVES spectrograph at the VLT, ESO, Chile (programmes 076.C-0706 and 177.C-0666) and 1.3-m Warsaw Telescope at Las Campanas Observatory, Chile. [less ▲]

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See detailCLÉS, Code Liégeois d'Évolution Stellaire
Scuflaire, Richard ULg; Théado, Sylvie; Montalban Iglesias, Josefa ULg et al

in Astrophysics & Space Science (2008), 316

CLÉS is an evolution code recently developed to produce stellar models meeting the specific requirements of studies in asteroseismology. It offers the users a lot of choices in the input physics they want ... [more ▼]

CLÉS is an evolution code recently developed to produce stellar models meeting the specific requirements of studies in asteroseismology. It offers the users a lot of choices in the input physics they want in their models and its versatility allows them to tailor the code to their needs and implement easily new features. We describe the features implemented in the current version of the code and the techniques used to solve the equations of stellar structure and evolution. A brief account is given of the use of the program and of a solar calibration realized with it. [less ▲]

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See detailDoes preoperative somatostatin analog treatment improve surgical cure rates in acromegaly? A new look at an old question.
Beckers, Albert ULg

in Journal of Clinical Endocrinology and Metabolism (2008), 93(8), 2975-2977

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See detail18F LABELING OF BIOMOLECULES USING CLICK CHEMISTRY FOR PET APPLICATIONS : SYNTHETIC DEVELOPMENTS
Thonon, David ULg; Flagothier, Jessica ULg; Paris, Jérôme ULg et al

in Drugs of the Future (2008, August), 33(A), 235

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See detailTuberculose intramédullaire. À propos d’un cas
Litré, Claude Fabien ULg; Pech Gourg, G; Acosta Diaz, U et al

in Neuro-Chirurgie (2008), 54(4), 545-7

Les manifestations neurologiques de la tuberculose restent rares, même si ces dernières années ont été marquées par une augmentation de ces pathologies, du fait, notamment, de la pandémie du VIH. Le ... [more ▼]

Les manifestations neurologiques de la tuberculose restent rares, même si ces dernières années ont été marquées par une augmentation de ces pathologies, du fait, notamment, de la pandémie du VIH. Le tuberculome intramédullaire reste une localisation exceptionnelle. Nous rapportons ici le cas d’un patient adulte non séropositif pour le virus VIH et non immunodéprimé présentant un tuberculome intramédullaire, découvert devant un tableau de compression médullaire lente. Nous discuterons le diagnostic radiologique, la nécessité ou non d’un traitement chirurgical, ainsi que les suites cliniques et, notamment, fonctionnelles. Notre expérience nous porte à croire que l’approche combinée de la chirurgie et de l’antibiothérapie paraît être la meilleure alternative. [less ▲]

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See detailDry heathlands and sandy open grasslands in a suburban environment in the south of Brussels (Belgium) : Assessment of the conservation status
Taymans, Julien ULg; Mahy, Grégory ULg

Poster (2008, August)

The Brabant sablo-limoneux region is located in the south and near Brussels, in the phytogeographic district of Brabant (Atlantic domain). This region is characterized by a high diversity of local ... [more ▼]

The Brabant sablo-limoneux region is located in the south and near Brussels, in the phytogeographic district of Brabant (Atlantic domain). This region is characterized by a high diversity of local ecological conditions due to the alternance of important tertiary sand outcrops and quaternary silty layers. The agro-sylvo-pastoral activities, which were practiced on these sandy and sand-silty soils for centuries, caused the evolution of the climactic forest into semi-natural habitats such as dry heathland, sandy grassland and grassheath. The evolution of the heathland distribution from 1770 to the present has been studied on the scale of the Dyle hydrographic subbasin (43.000 ha). It is characterized by an important regression of this habitat in the study area (from 1460 ha in 1770 to 72 ha in 2006), mainly due to Pinus sylvestris orchards, and more recently, to urbanisation caused by the proximity of Brussels. A generalized ageing and an environmental closing characterize the evolution of heathland physiognomy since the middle of the 20th century. The phytosociology of heathlands, sandy grasslands and grassheaths has been characterized and 19 groups of vegetation have been differentiated. Among the 393 listed higher plant species, more than 30 are of great conservation interest in the regional context. A hierarchisation of restoration priorities has been established on the scale of the studied hydrographic subbasin and management measures have been proposed. [less ▲]

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See detailImpact of different spectroscopic datasets on CH4 retrievals from Jungfraujoch FTIR spectra
Duchatelet, Pierre ULg; Mahieu, Emmanuel ULg; Demoulin, Philippe ULg et al

Poster (2008, August)

Methane (CH4) is released in the atmosphere by natural processes (e.g. wetlands, termites) as well as by anthropogenic activities (e.g. fossil fuel exploitation, rice agriculture, biomass burning, etc ... [more ▼]

Methane (CH4) is released in the atmosphere by natural processes (e.g. wetlands, termites) as well as by anthropogenic activities (e.g. fossil fuel exploitation, rice agriculture, biomass burning, etc). Due to its high warming potential and its relatively long chemical lifetime (~9 years), atmospheric methane plays a major role in the radiative forcing responsible of the greenhouse effect. Methane also affects climate by influencing tropospheric ozone and stratospheric water. The cycle of methane is complex and to understand it requires a complete study of its emissions and its budget of sources and sinks. High quality methane data sets are needed to perform such studies. CH4 vertical distributions as well as total and partial column time series can be retrieved from high-resolution ground-based FTIR spectra, using, e.g., the SFIT-2 algorithm which implements the Optimal Estimation Method of Rodgers. A set of 5 microwindows - located in the 2 to 5.5 µm range and jointly adopted by all partners involved in the European HYMN project (www.knmi.nl/samenw/hymn/) - are fitted simultaneously during the retrieval procedure. Although this approach provides relatively high information content, CH4 retrieved profiles very often present large oscillations in the troposphere, which might result partly from inappropriate or inconsistent spectroscopic parameters. Significant improvements on retrieval quality could be reached by using more accurate CH4 spectroscopic parameters. This contribution compares 3 different sets of CH4 spectroscopic parameters (including HITRAN 2004 and 2 versions where HITRAN 2004 have been updated by recent laboratory measurements), which have been tested using one year of high resolution FTIR solar observations performed at the International Scientific Station of the Jungfraujoch (Swiss Alps, 46.5°N, 8.0 °E, 3580m a.s.l.). The impact of these different spectroscopic datasets on retrieved CH4 partial columns and vertical profiles, as well as on the fitting quality (residuals) and on the error budget characterizing our CH4 products will be evaluated and discussed. [less ▲]

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See detailEvaluation de l’impact des propriétés tensioactives et d’hydrophobicité de surface sur le transfert gaz-liquide au sein d’un réacteur biphasique et son extrapolation
Gillet, Sébastien ULg

Poster (2008, August)

L’objectif du travail était d’une part d’évaluer la faisabilité d’une extrapolation du système et d’autre part de mieux comprendre l’impact des constituants de ce système biphasique sur le transfert de ... [more ▼]

L’objectif du travail était d’une part d’évaluer la faisabilité d’une extrapolation du système et d’autre part de mieux comprendre l’impact des constituants de ce système biphasique sur le transfert de masse gaz-liquide.En proposant une méthode d’estimation en continu de la stabilité de l’émulsion biphasique, ce travail permet de conclure à la possibilité d’un passage à une échelle plus grande.Pour mieux comprendre l’impact de la biomasse et du surfactant sur les mécanismes impliqués dans le transfert, une approche basée sur trois types de mesures est proposée. Cette approche, simple dans sa mise en oeuvre, présente l’avantage de se baser sur des mesures réelles, permettant de prendre en compte certains facteurs ignorés par les modèles mathématiques fournis dans la littérature. Le travail met en évidence une diminution du “ kLa ” au cours de la “ vie ” d’un réacteur biphasique. De plus, les mécanismes responsables de cette diminution ont également pu être identifiés. [less ▲]

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See detailAnalysis of ergosterol and the main Alternaria mycotoxins in cereals from endemic and non endemic KBD areas in TAR
Lognay, Georges ULg; Denis, Quentin; Chasseur, Camille et al

Conference (2008, August)

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See detailPlacing the academic library at the center of veterinary PhD students' training
Brouwir, Christine ULg; Vandenput, Sandrina ULg; Maas, Michel et al

in Journal of the European Association for Health Information and Libraries (2008, August), 4(3), 18-20

For several years academic librairies have been actively involved in information literacy instruction. However, the required competences are different for PhD students and in the case of the Veterinary ... [more ▼]

For several years academic librairies have been actively involved in information literacy instruction. However, the required competences are different for PhD students and in the case of the Veterinary Faculty of the University of Liège (Belgium), good Faculty-Librarian collaborations have been developed. Specific targeted courses and training sessions concerning information literacy have been officially incorporated in the PhD curriculum, with the main objective being to help PhD students to be autonomous and efficient in the elaboration of scientific publications, an essential stage of their scientific career. [less ▲]

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See detail3D finite‐element modeling for the magnetization of bulk high‐Tc drilled superconductors
Lousberg, Grégory ULg

Poster (2008, August)

Article associé : Numerical simulation of the magnetization of high-temperature superconductors: a 3D finite element method using a single time-step iteration

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See detailPoly(caprolactone)/clay masterbatches prepared in supercritical CO2 as efficient clay delamination promoters in poly(styrene-co-acrylonitrile)
Urbanczyk, Laetitia ULg; Calberg, Cédric ULg; Benali, Samira et al

in Journal of Materials Chemistry (2008), 18(39), 4623-4630

Poly(styrene-co-acrylonitrile) (SAN)/clay nanocomposites with a high degree of clay exfoliation were prepared upon melt blending of pre-exfoliated poly(-caprolactone) (PCL)/organoclay masterbatches in a ... [more ▼]

Poly(styrene-co-acrylonitrile) (SAN)/clay nanocomposites with a high degree of clay exfoliation were prepared upon melt blending of pre-exfoliated poly(-caprolactone) (PCL)/organoclay masterbatches in a Brabender-type internal mixer. These highly filled masterbatches were synthesized by a one-pot process using supercritical carbon dioxide as a polymerization medium. During their dispersion into SAN, PCL is expected to act as a compatibilizer at the polymer–clay interface as it is miscible with the host matrix under these conditions. Reference nanocomposites based on direct melt mixing of the commercial organoclay were also prepared for the sake of comparison. The superiority of the masterbatch route in term of clay delamination efficiency has been evidenced by XRD analysis, visual and TEM observations. The effect of the nanocomposite morphology on the polymer properties was then investigated. A substantial improvement of the fire behaviour and a decrease in gas permeability have been observed for the nanocomposite containing the highest level of clay exfoliation, accompanied with a higher brittleness as evidenced by traction and impact tests. [less ▲]

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See detailCharacterization of the porous structure of biodegradable scaffolds obtained with supercritical CO2 as foaming agent
Léonard, Angélique ULg; Calberg, Cédric ULg; Kerckhofs, Greet ULg et al

in Journal of Porous Materials (2008), 15(4), 397-403

Poly(ε-caprolactone) foams were prepared, via a batch process, by using supercritical CO2 as foaming agent. Their porous structure was characterized through mercury porosimetry, helium and mercury ... [more ▼]

Poly(ε-caprolactone) foams were prepared, via a batch process, by using supercritical CO2 as foaming agent. Their porous structure was characterized through mercury porosimetry, helium and mercury pycnometry, scanning electron microscopy (SEM) and X-ray microtomography observations coupled with image analysis. The pore size distributions obtained by these two latter techniques show that the pore structure is more homogeneous when the foaming process is performed under a high CO2 saturation pressure (higher than 250 bars). [less ▲]

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See detailMesoporous TiO2 thin films for photovoltaic applications
Dewalque, Jennifer ULg; Mathieu, Xavier; Decroly, André et al

Poster (2008, August)

Thin films of nanocrystalline, mesostructured titanium dioxide are very promising materials to build low cost and efficient photovoltaic devices. TiO2 present a high chemical stability and electronic ... [more ▼]

Thin films of nanocrystalline, mesostructured titanium dioxide are very promising materials to build low cost and efficient photovoltaic devices. TiO2 present a high chemical stability and electronic properties such as photo-induced electronic transfer properties associated with the anatase phase. For many applications, highly porous nanostructured thin films with accessible pores are preferable to dense ones. Indeed, high accessible porosity leads to high surface area increasing the electron transfer surface. [less ▲]

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See detailLocal Identification of Voltage Emergency Situations
Vournas, Costas; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2008), 23(3), 1239-1248

This paper proposes a simple procedure to identify the onset of long-term voltage instability from the time evolution of the distribution voltages controlled by load tap changers. The moving average of ... [more ▼]

This paper proposes a simple procedure to identify the onset of long-term voltage instability from the time evolution of the distribution voltages controlled by load tap changers. The moving average of sampled measurements is computed and used to trigger local emergency signals. The method is validated on voltage signals obtained from time simulation of a realistic test system. The ability to identify instability in the critical area is demonstrated in three test cases. [less ▲]

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