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See detailQuels modes de gouvernance pour la PMI tunisienne? Les enseignements de la littérature
Ghorbel, Jihene ULg; Van Caillie, Didier ULg

Conference (2012, April 02)

Les Petites et Moyennes Entreprises (PME), et tout particulièrement les Petites et Moyennes Industries (PMI), constituent un des piliers de l’économie tunisienne. Néanmoins, malgré l’abondance des études ... [more ▼]

Les Petites et Moyennes Entreprises (PME), et tout particulièrement les Petites et Moyennes Industries (PMI), constituent un des piliers de l’économie tunisienne. Néanmoins, malgré l’abondance des études consacrées aux PME dans le monde, rares sont les recherches scientifiques qui portent sur les spécificités des PME industrielles dans ce contexte géographique donné. Simultanément, face au phénomène de mondialisation croissante de l'économie et aux crises économiques et financières qui marquent la vie économique mondiale en cette première décennie du nouveau millénaire, un consensus émerge dans la littérature conduisant au constat que les PME et les PMI doivent impérativement renforcer et améliorer à la fois leurs systèmes de contrôle et de gouvernance si elles veulent jouer un rôle majeur dans leur tissu économique respectif et si elles souhaitent consolider leur crédibilité auprès de l'ensemble de leurs partenaires externes (banquiers, Pouvoirs Publics, organes de contrôle externes, ...). Notre contribution se propose dès lors, à partir d’une analyse de la littérature relativement limitée spécifique à l'objet de recherche particulier que constitue la PMI tunisienne, de mettre en évidence les spécificités de la PMI tunisienne et ses conséquences sur le design d'un système de gouvernance qui permettrait d'asseoir leur crédibilité et donc leur assise dans le paysage économique tunisien. [less ▲]

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See detailInstitutional Change and Legislative Stability: Explicit and Contested Decision-Making in the EU Council (1995-2010)
Van Aken, Wim ULg

E-print/Working paper (2012)

In contrast to general expectations the growth of EU membership as well as European treaty reform has not had any significant impact on the Council’s overall legislative and roll call activity. On the ... [more ▼]

In contrast to general expectations the growth of EU membership as well as European treaty reform has not had any significant impact on the Council’s overall legislative and roll call activity. On the basis of a new dataset representing the total population of public roll calls and recorded votes in the Council this paper explains why the EU Council has been so successful in guaranteeing legislative and roll call stability between 1995 and 2010. The quantitative and qualitative analysis finds that frontloading legislation, changing voting behaviour, reinforcement of existing coalition patterns and the successful adjustment of newer Member States to the EU Council have contributed to the EU Council’s decision-making capacity during the observed 16 years. In explaining the apparent contradiction between institutional change and the Council’s legislative stability this paper contributes to our knowledge of the functioning, the decision-making processes and the geography of contestation in the EU Council. [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 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 detailBarrier towards vortex redistribution in a partially nanopatterned superconductor
Shaw, Gorky ULg

Scientific conference (2012, April 01)

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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 detailMilk production of Holsteins under Mediterranean conditions: case of the Tunisian population
Ben Gara, Abderrahmen; Borni, Jemmali; Hammami, Hedi ULg et al

in Rekik, Boulbaba (Ed.) Milk Production (2012)

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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 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 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 detailDivision IV / Working Group on Massive Stars
Puls, Joachim; Leitherer, Claus; Owocki, Stan et al

in Transactions of the International Astronomical Union, Series B (2012), 28

Our Working Group (WG) studies massive, luminous stars, both individually and in resolved and unresolved populations, with historical focus on early-type (OB) stars, A-supergiants, and Wolf-Rayet stars ... [more ▼]

Our Working Group (WG) studies massive, luminous stars, both individually and in resolved and unresolved populations, with historical focus on early-type (OB) stars, A-supergiants, and Wolf-Rayet stars. Our group also studies lower mass stars (e.g., central stars of planetary nebulae and their winds) which display features similar or related to those present in massive stars, and thus may improve our understanding of the physical processes occurring in massive stars. In recent years, massive red supergiants that evolve from hot stars have been included into our activities as well. We emphasize the role of massive stars in other branches of astrophysics, particularly regarding the First Stars, long duration Gamma-Ray bursts, formation of massive stars and their feedback on star formation in general, pulsations of massive stars, and starburst galaxies. [less ▲]

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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 detailL'impact de la divulgation d'informations sur la liquidité du marché français
Ajina, Aymen ULg; Sougné, Danielle ULg; Lakhal, Faten

in Finance et Stratégies de Développement (2012)

This paper examines the relationship between the quality of financial disclosure and the French stock-market liquidity. Based on a sample of 196 firms over a period from 2004 to 2007, we find that there ... [more ▼]

This paper examines the relationship between the quality of financial disclosure and the French stock-market liquidity. Based on a sample of 196 firms over a period from 2004 to 2007, we find that there is a positive and statistically significant relationship between the quality of Annual Reports and market liquidity. This result should encourage French authorities to develop the informational environment as an indispensable means to prevent the risk of illiquidity. [less ▲]

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See detailDiscrimination thresholds of the reverberation in large volumes by naïve listeners
Billon, Alexis ULg; Embrechts, Jean-Jacques ULg

in Proceedings of the Acoustics 2012 Nantes conference (2012, April)

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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 detailThe Venus nitric oxide nightglow vertical distribution : update, new features and modelling
Stiepen, Arnaud ULg; Gérard, Jean-Claude ULg; Soret, Lauriane ULg et al

Poster (2012, April)

Ultraviolet (UV) spectra of the delta (190-240 nm) and gamma (225-270 nm) bands of the nitric oxide (NO) molecule have been measured in the atmosphere of the Venus night side with the Spectroscopy for ... [more ▼]

Ultraviolet (UV) spectra of the delta (190-240 nm) and gamma (225-270 nm) bands of the nitric oxide (NO) molecule have been measured in the atmosphere of the Venus night side with the Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) instrument on board Venus Express (VEX). Excited NO molecules on the night side of the planet find their source in the radiative recombinaison of O(3P) and N(4S) atoms produced on the dayside by Extreme Ultraviolet (EUV) solar photons that cause photodissociation of CO2 and N2 molecules. We analyse with an improved statistics the behaviour of the vertical emission profile of the NO nightglow. We also present a method used to retrieve and analyse the volume emission rate. We describe the dependence of the vertical distribution with latitude and local time and its variability. New features in the vertical distribution of the NO emission such as double peaks are also exhibited. Furthermore, we use a one-dimensional chemical-diffusive model to compare the major features of the calculated O2 1.27 microm and NO UV emissions profiles with those observed with SPICAV. [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 detailPoroelastic Center of Dilation Revisited
Huynen, Alexandre ULg

Master of advanced studies dissertation (2012)

In both elasticity and poroelasticity, the nucleus of strain is usually used to refer to a singular solution such as the point force, the force dipole, the centers of rotation and dilation, etc. These ... [more ▼]

In both elasticity and poroelasticity, the nucleus of strain is usually used to refer to a singular solution such as the point force, the force dipole, the centers of rotation and dilation, etc. These fundamentals solutions constitute the building blocks for various problems of practical importance and are, therefore, relatively well understood. However, a comparison of the original elastic solution for the center of dilation with the classic Lamé solution reveals an unexpected dependence of the center of dilation solution on the Poisson’s ratio. This inconsistency is investigated by means of two alternative representations of the singularity and leads to the identification of a compressed zone inside the singularity. The poroelastic equivalent to this nucleus of strain is shown to be the superposition of the elastic one with drained material parameters and an instantaneous point fluid source associated with a finite volume of fluid that is expelled from the compressed region inside the singularity and is injected in the porous medium. [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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