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See detailCLUPI, a high-performance imaging system on the ESA-NASA rover of the 2018 ExoMars mission to discover biofabrics on Mars
Josset, J.-L.; Westall, F.; Hofmann, B. A. et al

in EGU General Assembly Conference Abstracts (2012, April 01)

The scientific objectives of the ESA-NASA rover of the 2018 mission of the ExoMars Programme are to search for traces of past or present life and to characterise the near-sub surface. Both objectives ... [more ▼]

The scientific objectives of the ESA-NASA rover of the 2018 mission of the ExoMars Programme are to search for traces of past or present life and to characterise the near-sub surface. Both objectives require study of the rock/regolith materials in terms of structure, textures, mineralogy, and elemental and organic composition. The 2018 rover ExoMars payload consists of a suite of complementary instruments designed to reach these objectives. CLUPI, the high-performance colour close up imager, on board the 2018 ESA-NASA Rover plays an important role in attaining the mission objectives: it is the equivalent of the hand lens that no geologist is without when undertaking field work. CLUPI is a powerful, highly integrated miniaturized (<700g) low-power robust imaging system, able to operate at very low temperatures (-120°C). CLUPI has a working distance from 10cm to infinite providing outstanding pictures with a color detector of 2652x1768. At 10cm, the resolution is 7 micrometer/pixel in color. The focus mechanism and the optical-mechanical interface are a smart assembly in titanium that can sustain a wide temperature range. The concept benefits from well-proven heritage: Proba, Rosetta, MarsExpress and Smart-1 missions… Because the main science objective of ExoMars concerns the search for life, whose traces on Mars are likely to be cryptic, close up observation of the rocks and granular regolith will be critical to the decision as whether to drill and sample the nearby underlying materials. Thus, CLUPI is the essential final step in the choice of drill site. But not only are CLUPI's observations of the rock outcrops important, but they also serve other purposes. CLUPI, could observe the placement of the drill head. It will also be able to observe the fines that come out of the drill hole, including any colour stratification linked to lithological changes with depth. Finally, CLUPI will provide detailed observation of the surface of the core drilled materials when they are in the sample drawer at a spatial resolution of 15 micrometer/pixel in color. The close-up imager CLUPI on the ESA-NASA rover of the 2018 mission will be described together with its capabilities to provide important information significantly contributing to the understanding of the geological environment and could identify outstanding potential biofabrics (stromatolites...) of past life on Mars. [less ▲]

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See detailDes racines au faîte : Hubert Nyssen romancier
Durand, Pascal ULg

in Bon-A-Tirer : Revue Littéraire en Ligne (2012), 156

Aspects esthétiques et politiques de l'imaginaire romanesque d'Hubert Nyssen, par ailleurs fondateur des éditions Actes Sud.

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See detailThree quasi-stellar objects acting as strong gravitational lenses
Courbin, F.; Faure, C.; Djorgovski, S. G. et al

in Astronomy and Astrophysics (2012), 540

We report the discovery of three new cases of quasi-stellar objects (QSOs) acting as strong gravitational lenses on background emission line galaxies: SDSS J0827+5224 (z[SUB]QSO[/SUB] = 0.293, z[SUB]s ... [more ▼]

We report the discovery of three new cases of quasi-stellar objects (QSOs) acting as strong gravitational lenses on background emission line galaxies: SDSS J0827+5224 (z[SUB]QSO[/SUB] = 0.293, z[SUB]s[/SUB] = 0.412), SDSS J0919+2720 (z[SUB]QSO[/SUB] = 0.209, z[SUB]s[/SUB] = 0.558), SDSS J1005+4016 (z[SUB]QSO[/SUB] = 0.230, z[SUB]s[/SUB] = 0.441). The selection was carried out using a sample of 22,298 SDSS spectra displaying at least four emission lines at a redshift beyond that of the foreground QSO. The lensing nature is confirmed from Keck imaging and spectroscopy, as well as from HST/WFC3 imaging in the F475W and F814W filters. Two of the QSOs have face-on spiral host galaxies and the third is a QSO+galaxy pair. The velocity dispersion of the host galaxies, inferred from simple lens modeling, is between σ = 210 and 285 km s[SUP]-1[/SUP], making these host galaxies comparable in mass with the SLACS sample of early-type strong lenses. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Also based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #GO12233. [less ▲]

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See detailGlobal Modeling of X-Ray Spectra Produced in O-type Star Winds
Hervé, Anthony ULg; Rauw, Grégor ULg; Nazé, Yaël ULg et al

in Astrophysical Journal (2012), 748

High-resolution X-ray spectra of O-type stars revealed less wind absorption than expected from smooth winds with conventional mass-loss rates. Various solutions have been proposed, including porous winds ... [more ▼]

High-resolution X-ray spectra of O-type stars revealed less wind absorption than expected from smooth winds with conventional mass-loss rates. Various solutions have been proposed, including porous winds, optically thick clumps, or an overall reduction of the mass-loss rates. The latter has a strong impact on the evolution of the star. Our final goal is to analyze high-resolution X-ray spectra of O-type stars with a multi-temperature plasma model in order to determine crucial stellar and wind parameters such as the mass-loss rate, the CNO abundances, and the X-ray temperature plasma distribution in the wind. In this context we are developing a modeling tool to calculate synthetic X-ray spectra. We present here the main ingredients and physics necessary for such a work. Our code uses the most recent version of the AtomDB emissivities to compute the intrinsic emissivity of the hot plasma as well as the CMFGEN model atmosphere code to evaluate the opacity of the cool wind. Following the comparison between two formalisms of stellar wind fragmentation, we introduce, for the first time in X-rays, the effects of a tenuous inter-clump medium. We then explore the quantitative impact of different model parameters on the X-ray spectra such as the position in the wind of the X-ray emitting plasma. For the first time, we also show that the two formalisms of stellar wind fragmentation yield different results, although the differences for individual lines are small and can probably not be tested with the current generation of X-ray telescopes. As an illustration of our method, we compare various synthetic line profiles to the observed O VIII λ18.97 line in the spectrum of ζ Puppis. We illustrate how different combinations of parameters can actually lead to the same morphology of a single line, underlining the need to analyze the whole spectrum in a consistent way when attempting to constrain the parameters of the wind. [less ▲]

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See detailDamping rates of solar-like oscillations across the HR diagram. Theoretical calculations confronted to CoRoT and Kepler observations
Belkacem, K.; Dupret, Marc-Antoine ULg; Baudin, F. et al

in Astronomy and Astrophysics (2012), 540

The space-borne missions CoRoT and Kepler are providing a rich harvest of high-quality constraints on solar-like pulsators. Among the seismic parameters, mode damping rates remains poorly understood and ... [more ▼]

The space-borne missions CoRoT and Kepler are providing a rich harvest of high-quality constraints on solar-like pulsators. Among the seismic parameters, mode damping rates remains poorly understood and are thus barely used to infer the physical properties of stars. Nevertheless, thanks to the CoRoT and Kepler spacecrafts it is now possible to measure damping rates for hundreds of main-sequence and thousands of red-giant stars with unprecedented precision. By using a non-adiabatic pulsation code including a time-dependent convection treatment, we compute damping rates for stellar models that are representative of solar-like pulsators from the main-sequence to the red-giant phase. This allows us to reproduce the observations of both CoRoT and Kepler, which validates our modeling of mode damping rates and thus the underlying physical mechanisms included in the modeling. By considering the perturbations of turbulent pressure and entropy (including the perturbation of the dissipation rate of turbulent energy into heat) by the oscillation in our computation, we succeed in reproducing the observed relation between damping rates and effective temperature. Moreover, we discuss the physical reasons for mode damping rates to scale with effective temperature, as observationally exhibited. Finally, this opens the way for the use of mode damping rates to probe turbulent convection in solar-like stars. [less ▲]

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See detailEvidence for a physically bound third component in HD 150136
Mahy, Laurent ULg; Gosset, Eric ULg; Sana, H et al

in Astronomy and Astrophysics (2012), 540

Context. HD 150136 is one of the nearest systems harbouring an O3 star. Although this system was considered for a long time as a binary, more recent investigations have suggested the possible existence of ... [more ▼]

Context. HD 150136 is one of the nearest systems harbouring an O3 star. Although this system was considered for a long time as a binary, more recent investigations have suggested the possible existence of a third component. <BR /> Aims: We present a detailed analysis of HD 150136 to test its triple nature. In addition, we investigate the physical properties of the individual components of this system. <BR /> Methods: We analysed high-resolution, high signal-to-noise data collected through multi-epoch runs spread over ten years. We applied a disentangling program to refine the radial velocities and to obtain the individual spectra of each star. With the radial velocities, we computed the orbital solution of the inner system, and we describe the main properties of the orbit of the outer star such as the preliminary mass ratio, the eccentricity, and the orbital-period range. With the individual spectra, we determined the stellar parameters of each star by means of the CMFGEN atmosphere code. <BR /> Results: We offer clear evidence that HD 150136 is a triple system composed of an O3V((f[SUP]∗[/SUP]))-3.5V((f[SUP]+[/SUP])), an O5.5-6V((f)), and an O6.5-7V((f)) star. The three stars are between 0-3 Myr old. We derive dynamical masses of about 64, 40, and 35 M[SUB]&sun;[/SUB] for the primary, the secondary and the third components by assuming an inclination of 49° (sin[SUP]3[/SUP]i = 0.43). It currently corresponds to one of the most massive systems in our galaxy. The third star moves with a period in the range of 2950 to 5500 d on an outer orbit with an eccentricity of at least 0.3. However, because of the long orbital period, our dataset is not sufficient to constrain the orbital solution of the tertiary component with high accuracy. <BR /> Conclusions: We confirm there is a tertiary star in the spectrum of HD 150136 and show that it is physically bound to the inner binary system. This discovery makes HD 150136 the first confirmed triple system with an O3 primary star. Table 1 is available in electronic form at <A href="http://www.aanda.org">http://www.aanda.org</A> [less ▲]

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See detailBarrier towards vortex redistribution in a partially nanopatterned superconductor
Shaw, Gorky ULg

Scientific conference (2012, April 01)

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See detailRossiter-McLaughlin effect measurements for WASP-16, WASP-25 and WASP-31★
Brown, D J A; Cameron, A Collier; Anderson, D R et al

in Monthly Notices of the Royal Astronomical Society (2012)

We present new measurements of the Rossiter-McLaughlin (RM) effect for three Wide Angle Search for transiting Planets (WASP) planetary systems, WASP-16, WASP-25 and WASP-31, from a combined analysis of ... [more ▼]

We present new measurements of the Rossiter-McLaughlin (RM) effect for three Wide Angle Search for transiting Planets (WASP) planetary systems, WASP-16, WASP-25 and WASP-31, from a combined analysis of their complete sets of photometric and spectroscopic data. We find a low-amplitude RM effect for WASP-16 (T[SUB]eff[/SUB]= 5700 ± 150 K), suggesting that the star is a slow rotator and thus of an advanced age, and obtain a projected alignment angle of ?. For WASP-25 (T[SUB]eff[/SUB]= 5750 ± 100 K), we detect a projected spin-orbit angle of λ= 14°.6 ± 6°.7. WASP-31 (T[SUB]eff[/SUB]= 6300 ± 100 K) is found to be well aligned, with a projected spin-orbit angle of λ= 2°.8 ± 3°.1. A circular orbit is consistent with the data for all three systems, in agreement with their respective discovery papers. We consider the results for these systems in the context of the ensemble of RM measurements made to date. We find that whilst WASP-16 fits the hypothesis of Winn et al. that 'cool' stars (T[SUB]eff[/SUB] < 6250 K) are preferentially aligned, WASP-31 has little impact on the proposed trend. We bring the total distribution of the true spin-orbit alignment angle, ψ, up to date, noting that recent results have improved the agreement with the theory of Fabrycky & Tremaine at mid-range angles. We also suggest a new test for judging misalignment using the Bayesian information criterion, according to which WASP-25 b's orbit should be considered to be aligned. [less ▲]

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See detailUse of ionic liquids for biocatalytic synthesis of sugar derivatives
Galonde, Nadine ULg; Nott, Katherine ULg; Debuigne, Antoine ULg et al

in Journal of Chemical Technology & Biotechnology (2012), 87(4), 451-471

Sugar-based compounds are widely used in pharmaceuticals, cosmetics, detergents and food. They are mainly produced by chemical methods, but the use of enzymes as ‘a greener alternative’ to organic ... [more ▼]

Sugar-based compounds are widely used in pharmaceuticals, cosmetics, detergents and food. They are mainly produced by chemical methods, but the use of enzymes as ‘a greener alternative’ to organic synthesis has been investigated for more than 20 years. Due to the low polar substrate solubility in organic solvents compatible with enzymes, research has focused on the application of substitutes for biocatalysis, especially ionic liquids (ILs). After introducing the main properties of ILs and especially their ability to solubilize sugars, this review focuses on one of their applications, the biocatalytic synthesis of carbohydrate derivatives. In this context, they can be used in pure IL systems, in IL/IL systems or in IL/organic solvent systems. Finally, this review provides an update on the environmental fate of ILs. Their exploitation in ‘green’ processes is still limited due to their low degradability but research is currently under way to design new more ‘eco-friendly’ ILs. [less ▲]

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See detailDynamique forestière et enrichissements forestiers. Site de Mbang. Rapport n° 8.
Doucet, Jean-Louis ULg; Amandé, Jean; Bracke, Charles et al

Report (2012)

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See detailNatural Killer cells - role in local tumor growth and metastasis
Langers, Inge ULg; Renoux, Virginie ULg; Thiry, Marc ULg et al

in Biologics: Targets and Therapy (2012)

Historically, the name of Natural Killer (NK) cells came from their natural ability to kill tumor cells in vitro. From the seventies to date, accumulating data highlighted the importance of NK cells in ... [more ▼]

Historically, the name of Natural Killer (NK) cells came from their natural ability to kill tumor cells in vitro. From the seventies to date, accumulating data highlighted the importance of NK cells in host immune response against cancer and in therapy-induced anti-tumor response. The recognition and the lysis of tumor cells by NK cells are regulated by a complex balance of inhibitory and activating signals. This review summarizes NK cell mechanisms to kill cancer cells, their role in host immune responses against tumor growth or metastasis and their implications in anti-tumor immunotherapies via cytokines, antibodies or in combination with other therapies. The regulatory role of NK cells in autoimmunity is also discussed. [less ▲]

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See detailPrésentation des résultats de la recherche SAFE
Reiter, Sigrid ULg; Marique, Anne-Françoise ULg; de Meester, Tatiana

Conference given outside the academic context (2012)

Présentation des résultats de la recherche SAFE et d'un outil interactif permettant à différentes catégories d'utilisateurs d'estimer les consommations d'énergie relatives à leur logement et à leur ... [more ▼]

Présentation des résultats de la recherche SAFE et d'un outil interactif permettant à différentes catégories d'utilisateurs d'estimer les consommations d'énergie relatives à leur logement et à leur déplacements, à les comparer et à trouver des pistes concrètes d'amélioration. [less ▲]

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See detailMechanical Ventilation During Anaesthesia: Pathophysiology and Clinical Implications
Dresse, Caroline; JORIS, Jean ULg; HANS, Grégory ULg

in Trends in Anaesthesia and Critical Care (2012), 2(2), 71-75

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See detailMapping error due to image geometric correction.
Hallot, Eric ULg; Cornet, Yves ULg; Hallot, Pierre ULg

Poster (2012, April)

Nowadays, image processing and GIS tools are more accessible and available to all. Most of diachronical or historical studies use the image geometric correction with several documents like old maps, plans ... [more ▼]

Nowadays, image processing and GIS tools are more accessible and available to all. Most of diachronical or historical studies use the image geometric correction with several documents like old maps, plans or aerial photographs. They are usually based on low-order polynomial equation to perfom these kinds of simplistic uses. Most of commercial softwares provide us a total or by ground control points RMSE but they don’t offer a overview of the spatial error distribution. More this does not guarantee that its significance for the other points of the image. Do not consider these errors can lead to erroneous observations and misinterpretations like historical moving streams or bank erosion rate. Using a least square adjustment (LSA), allow to recalculate the transformation equation from the pairs of control points coordinates. Assuming that residuals are spatially auto-correlated, we can build error vectors whose direction and magnitude symbolize the error at each point of the image. By another way, LSA manage the precision during transformation process by using a stochastic model in addition of the mathematical model during the transformation. This gives us variance on parameters of the transformation. Knowing the precision of all elements and variance/covariance matrix on transformation parameters, we apply variance propagation on the model. As an output, we obtain confidence ellipses on each transformed points, thus a spatial distribution of error for the entire image. Moreover, this leads us to determine statistically if observed movement are significant or not. The represent error is a complex problem that cannot be solved with a quick fix. In this work, we present an interesting example of using well-known topographic methods to solve image processing problems. [less ▲]

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See detailTwo distinct origins of long-term learning effects in verbal short-term memory?
Majerus, Steve ULg; Oberauer, K.

Conference (2012, April)

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See detailQuerelles d’écrivains (XIXe-XXIe siècles) : de la dispute à la polémique, dans COnTEXTES, revue de sociologie de la littérature
Stienon, Valérie ULg; Groupe de contact FNRS Contextes en sociologie de la littérature

Book published by Université de Liège (2012)

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See detailMeasuring the phase of the scattering amplitude with vortex beams
Ivanov, Igor ULg

in Physical Review. D : Particles and Fields (2012), 85(7), 07600110

We show that colliding vortex beams instead of (approximate) plane waves can lead to a direct measurement of how the overall phase of the plane wave scattering amplitude changes with the scattering angle ... [more ▼]

We show that colliding vortex beams instead of (approximate) plane waves can lead to a direct measurement of how the overall phase of the plane wave scattering amplitude changes with the scattering angle. Since vortex beams are coherent superpositions of plane waves with different momenta, their scattering amplitude receives contributions from plane wave amplitudes with distinct kinematics. These contributions interfere, leading to the measurement of their phase difference. Although interference exists for any generic wave packet collision, we show that using vortex beams dramatically enhances sensitivity to the phase in comparison with nonvortex beams. Since the overall phase is inaccessible in a plane wave collision, this measurement would be of great importance for a number of topics in hadronic physics, for example, meson production in the resonance region, physics of nucleon resonances, and small angle elastic hadron scattering. [less ▲]

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See detailInorganic carbon dynamics in coastal arctic sea ice and related air-ice CO2 exchanges
Geilfus, Nicolas-Xavier ULg; Tison, J.-L.; Carnat, G. et al

Poster (2012, April)

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