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See detailSpectral modelling of circular massive binary systems. Towards an understanding of the Struve-Sahade effect?
Palate, Matthieu ULg; Rauw, Grégor ULg

in Astronomy and Astrophysics (2012), 537

Context. Some secondary effects are known to introduce variations in spectra of massive binaries. These phenomena, such as the Struve-Sahade effect and the difficulties in determining properly the ... [more ▼]

Context. Some secondary effects are known to introduce variations in spectra of massive binaries. These phenomena, such as the Struve-Sahade effect and the difficulties in determining properly the spectral type have been reported and documented in the literature. <BR /> Aims: We simulate the spectra of circular massive binaries at different phases of the orbital cycle and account for the gravitational influence of the companion star on the shape and physical properties of the stellar surface. <BR /> Methods: We use the Roche potential to compute the stellar surface, von Zeipel theorem, and reflection effects to compute the surface temperature. We then interpolate in a grid of non-local thermodynamic equilibrium (NLTE) plan-parallel atmosphere model spectra to obtain the local spectrum at each surface point. We finally sum all the contributions, accounting for the reflection, Doppler shift, and limb-darkening to obtain the total spectrum. The computation is done for different orbital phases and for different sets of physical and orbital parameters. <BR /> Results: Our models reproduce the Struve-Sahade effect for several lines. Another effect on the surface temperature distribution is visible but the distribution predicted by our current model is not yet consistent with observations. <BR /> Conclusions: In some cases, the Struve-Sahade effect as well as more complex line intensity variations could be linked to blends of intrinsically asymmetric line profiles that are not appropriately treated by the deblending routine. Systematic variations in the lines of (nearly) contact systems are also predicted by the model. [less ▲]

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See detailVADE-MECUM des mammites bovines
Durel, Luc; Guyot, Hugues ULg; Theron, Léonard ULg

Book published by MED'COM (2012)

La mammite demeure la pathologie la plus préjudiciable à l'élevage des bovins laitiers. C'est une maladie multifactorielle fortement pénalisante pour l'éleveur: baisse de production, baisse de prix d ... [more ▼]

La mammite demeure la pathologie la plus préjudiciable à l'élevage des bovins laitiers. C'est une maladie multifactorielle fortement pénalisante pour l'éleveur: baisse de production, baisse de prix d'achat du lait, réformes anticipées, frais médicaux... Le lait étant par ailleurs au coeur de l'industrie alimentaire, la question de sa qualité reste primordiale et le vétérinaire a un rôle important à jouer. Ce Vade-Mecum des mammites bovines a pour vocation d'être un outil à la disposition du vétérinaire sur le terrain. Il aidera le praticien à analyser la situation pour laquelle il a été appelé, à proposer des solutions adaptées, tout en communiquant les connaissances nécessaires à l'éleveur pour emporter son adhésion et faire évoluer ses pratiques. L'ouvrage est divisé en 11 chapitres interdépendants explorant de façon approfondie chaque aspect du contrôle de la maladie, en s'appuyant sur les données les plus récentes: caractéristiques des mammites, approche clinique du troupeau, bâtiments, système de traite, alimentation et troubles métaboliques, traite, diagnostic étiologique, traitement en lactation, traitement hors lactation, réformes et gestion du troupeau, ou encore biosécurité. Ce livre raisonné et pragmatique trouvera sa place dans tous les véhicules des praticiens. [less ▲]

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See detailFast core rotation in red-giant stars as revealed by gravity-dominated mixed modes
Beck, Paul G; Montalban Iglesias, Josefa ULg; Kallinger, Thomas et al

in Nature (2012), 481

When the core hydrogen is exhausted during stellar evolution, the central region of a star contracts and the outer envelope expands and cools, giving rise to a red giant. Convection takes place over much ... [more ▼]

When the core hydrogen is exhausted during stellar evolution, the central region of a star contracts and the outer envelope expands and cools, giving rise to a red giant. Convection takes place over much of the star's radius. Conservation of angular momentum requires that the cores of these stars rotate faster than their envelopes; indirect evidence supports this. Information about the angular-momentum distribution is inaccessible to direct observations, but it can be extracted from the effect of rotation on oscillation modes that probe the stellar interior. Here we report an increasing rotation rate from the surface of the star to the stellar core in the interiors of red giants, obtained using the rotational frequency splitting of recently detected `mixed modes'. By comparison with theoretical stellar models, we conclude that the core must rotate at least ten times faster than the surface. This observational result confirms the theoretical prediction of a steep gradient in the rotation profile towards the deep stellar interior. [less ▲]

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See detailLow-Flow, Low-Gradient Severe Aortic Stenosis Despite Normal Ejection Fraction Is Associated With Severe Left Ventricular Dysfunction as Assessed by Speckle-Tracking Echocardiography: A Multicenter Study.
Adda, J.; Mielot, C.; Giorgi, R. et al

in Circulation: cardiovascular imaging (2012)

Background- Low-flow low-gradient (LFLG) is sometimes observed in severe aortic stenosis (AS) despite normal ejection fraction, but its frequency and mechanisms are still debated. We aimed to describe the ... [more ▼]

Background- Low-flow low-gradient (LFLG) is sometimes observed in severe aortic stenosis (AS) despite normal ejection fraction, but its frequency and mechanisms are still debated. We aimed to describe the characteristics of patients with LFLG AS and assess the presence of longitudinal left ventricular dysfunction in these patients. Methods and Results- In a multicenter prospective study, 340 consecutive patients with severe AS and normal ejection fraction were studied. Longitudinal left ventricular function was assessed by 2D-strain and global afterload by valvulo-arterial impedance. Patients were classified according to flow and gradient: low flow was defined as a stroke volume index ≤35 mL/m(2), low gradient as a mean gradient ≤40 mm Hg. Most patients (n=258, 75.9%) presented with high-gradient AS, and 82 patients (24.1%) with low-gradient AS. Among the latter, 52 (15.3%) presented with normal flow and low gradient and 30 (8.8%) with LFLG. As compared with normal flow and low gradient, patients with LFLG had more severe AS (aortic valve area=0.7±0.12 cm(2) versus 0.86±0.14 cm(2)), higher valvulo-arterial impedance (5.5±1.1 versus 4±0.8 mm Hg/mL/m(2)), and worse longitudinal left ventricular function (basal longitudinal strain=-11.6±3.4 versus -14.8±3%; P<0.001 for all). Conclusions- LFLG AS is observed in 9% of patients with severe AS and normal ejection fraction and is associated with high global afterload and reduced longitudinal systolic function. Patients with normal-flow low-gradient AS are more frequent and present with less severe AS, normal afterload, and less severe longitudinal dysfunction. Severe left ventricular longitudinal dysfunction is a new explanation to the concept of LFLG AS. [less ▲]

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See detailAssessing the accuracy of the surface gravity determination in late-type stars with solar-like pulsators
Morel, Thierry ULg; Miglio, Andrea ULg

in Monthly Notices of the Royal Astronomical Society (2012), 419

The frequency of maximum oscillation power measured in dwarfs and giants exhibiting solar-like pulsations provides a precise, and potentially accurate, inference of the stellar surface gravity. An ... [more ▼]

The frequency of maximum oscillation power measured in dwarfs and giants exhibiting solar-like pulsations provides a precise, and potentially accurate, inference of the stellar surface gravity. An extensive comparison for about 40 well-studied pulsating stars with gravities derived using classical methods (ionization balance, pressure-sensitive spectral features or location with respect to evolutionary tracks) supports the validity of this technique and reveals an overall remarkable agreement with mean differences not exceeding 0.05 dex (although with a dispersion of up to ˜0.2 dex). It is argued that interpolation in theoretical isochrones may be the most precise way of estimating the gravity by traditional means in nearby dwarfs. Attention is drawn to the usefulness of seismic targets as benchmarks in the context of large-scale surveys. [less ▲]

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See detailAsteroseismology of old open clusters with Kepler: direct estimate of the integrated red giant branch mass-loss in NGC 6791 and 6819
Miglio, A.; Brogaard, K.; Stello, D. et al

in Monthly Notices of the Royal Astronomical Society (2012), 419

Mass-loss of red giant branch (RGB) stars is still poorly determined, despite its crucial role in the chemical enrichment of galaxies. Thanks to the recent detection of solar-like oscillations in G-K ... [more ▼]

Mass-loss of red giant branch (RGB) stars is still poorly determined, despite its crucial role in the chemical enrichment of galaxies. Thanks to the recent detection of solar-like oscillations in G-K giants in open clusters with Kepler, we can now directly determine stellar masses for a statistically significant sample of stars in the old open clusters NGC 6791 and 6819. The aim of this work is to constrain the integrated RGB mass-loss by comparing the average mass of stars in the red clump (RC) with that of stars in the low-luminosity portion of the RGB [i.e. stars with L≲L(RC)]. Stellar masses were determined by combining the available seismic parameters ν[SUB]max[/SUB] and Δν with additional photometric constraints and with independent distance estimates. We measured the masses of 40 stars on the RGB and 19 in the RC of the old metal-rich cluster NGC 6791. We find that the difference between the average mass of RGB and RC stars is small, but significant [? (random) ±0.04 (systematic) M[SUB]&sun;[/SUB]]. Interestingly, such a small ? does not support scenarios of an extreme mass-loss for this metal-rich cluster. If we describe the mass-loss rate with Reimers prescription, a first comparison with isochrones suggests that the observed ? is compatible with a mass-loss efficiency parameter in the range 0.1 ≲η≲ 0.3. Less stringent constraints on the RGB mass-loss rate are set by the analysis of the ˜2 Gyr old NGC 6819, largely due to the lower mass-loss expected for this cluster, and to the lack of an independent and accurate distance determination. In the near future, additional constraints from frequencies of individual pulsation modes and spectroscopic effective temperatures will allow further stringent tests of the Δν and ν[SUB]max[/SUB] scaling relations, which provide a novel, and potentially very accurate, means of determining stellar radii and masses. [less ▲]

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See detailThe spectral variability and magnetic field characteristics of the Of?p star HD 148937
Wade, G. A.; Grunhut, J.; Gräfener, G. et al

in Monthly Notices of the Royal Astronomical Society (2012), 419

We report magnetic and spectroscopic observations and modelling of the Of?p star HD 148937 within the context of the Magnetism in Massive Stars (MiMeS) Large Program at the Canada-France-Hawaii Telescope ... [more ▼]

We report magnetic and spectroscopic observations and modelling of the Of?p star HD 148937 within the context of the Magnetism in Massive Stars (MiMeS) Large Program at the Canada-France-Hawaii Telescope. 32 high signal-to-noise ratio circularly polarized (Stokes V) spectra and 13 unpolarized (Stokes I) spectra of HD 148937 were acquired in 2009 and 2010. A definite detection of a Stokes V Zeeman signature is obtained in the grand mean of all observations [in both least-squares deconvolved (LSD) mean profiles and individual spectral lines]. The longitudinal magnetic field inferred from the Stokes V LSD profiles is consistently negative, in contrast to the essentially zero field strength measured from the diagnostic null profiles. A period search of new and archival equivalent width measurements confirms the previously reported 7.03 d variability period. The variation of equivalent widths is not strictly periodic: we present evidence for evolution of the amount or distribution of circumstellar plasma. Interpreting the 7.03 d period as the stellar rotational period within the context of the oblique rotator paradigm, we have phased the equivalent widths and longitudinal field measurements. The longitudinal field measurements show a weak sinusoidal variation of constant sign, with extrema out of phase with the Hα variation by about 0.25 cycles. From our constraint on v sin i≤ 45 km s[SUP]-1[/SUP], we infer that the rotational axis inclination i≤ 30°. Modelling the longitudinal field phase variation directly, we obtain the magnetic obliquity β= 38[SUP]+17[/SUP][SUB]-28[/SUB]° and dipole polar intensity B[SUB]d[/SUB]= 1020[SUP]-380[/SUP][SUB]+310[/SUB] G. Simple modelling of the Hα equivalent width variation supports the derived geometry. The inferred magnetic configuration confirms the suggestion of Nazé et al., who proposed that the weaker variability of HD 148937 as compared to other members of this class is a consequence of the stellar geometry. Based on the derived magnetic properties and published wind characteristics, we find a wind magnetic confinement parameter η[SUB]*[/SUB]≃ 20 and rotation parameter W= 0.12, supporting a picture in which the Hα emission and other line variability have their origin in an oblique, rigidly rotating magnetospheric structure resulting from a magnetically channelled wind. [less ▲]

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See detailThe remarkable surface homogeneity of the Dawn mission target (1) Ceres
Carry, Benoît; Vernazza, Pierre; Dumas, Christophe et al

in Icarus (2012), 217

Dwarf-planet (1) Ceres is one of the two targets, along with (4) Vesta, that will be studied by the NASA Dawn spacecraft via imaging, visible and near-infrared spectroscopy, and gamma-ray and neutron ... [more ▼]

Dwarf-planet (1) Ceres is one of the two targets, along with (4) Vesta, that will be studied by the NASA Dawn spacecraft via imaging, visible and near-infrared spectroscopy, and gamma-ray and neutron spectroscopy. While Ceres' visible and near-infrared disk-integrated spectra have been well characterized, little has been done about quantifying spectral variations over the surface. Any spectral variation would give us insights on the geographical variation of the composition and/or the surface age. The only work so far was that of Rivkin and Volquardsen ([2010], Icarus 206, 327) who reported rotationally-resolved spectroscopic (disk-integrated) observations in the 2.2-4.0 μm range; their observations showed evidence for a relatively uniform surface.Here, we report disk-resolved observations of Ceres with SINFONI (ESO VLT) in the 1.17-1.32 μm and 1.45-2.35 μm wavelength ranges. The observations were made under excellent seeing conditions (0.6″), allowing us to reach a spatial resolution of ˜75 km on Ceres' surface. We do not find any spectral variation above a 3% level, suggesting a homogeneous surface at our spatial resolution. Slight variations (about 2%) of the spectral slope are detected, geographically correlated with the albedo markings reported from the analysis of the HST and Keck disk-resolved images of Ceres (Li et al. [2006], Icarus 182, 143; Carry et al. [2008], Astron. Astrophys. 478, 235). Given the lack of constraints on the surface composition of Ceres, however, we cannot assert the causes of these variations. [less ▲]

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See detailConsumer valuation of improved rice parboiling technologies in Benin
Matty, Demont; Zossou, Enangnon ULg; Pieter, Rutsaert et al

in Food Quality & Preference (2012), 23(1), 63-70

In Benin, traditional parboiling is still widely practiced among rice processors, resulting in inferior grain quality. A new parboiler was introduced to improve the milling yield and intrinsic quality of ... [more ▼]

In Benin, traditional parboiling is still widely practiced among rice processors, resulting in inferior grain quality. A new parboiler was introduced to improve the milling yield and intrinsic quality of local rice. We conducted Vickrey second price auctions to elicit rural Beninese consumers’ willingness to pay for rice obtained through the new parboiler and two locally innovated parboilers. The individual auctions were followed by a group discussion during which consensus was reached on socially acceptable prices. Relative to traditionally parboiled rice, consumers were willing to pay price premiums of 9–13% for rice obtained through a local parboiler using a container of which the bottom is a perforated metal, 27% for rice obtained through a local parboiler using wooden sticks at the bottom of the pot, and 25–34% for rice parboiled through the improved parboiler. Bids were influenced by the presentation order of the products according to perceived quality. Bids were also higher when participants had been informed on the benefits of improved parboiling techniques, which is a crucial insight for developing marketing and communication strategies for this improved quality product. Group bids were not significantly different from individual bids which suggests that the latter are within the range of socially acceptable prices defined through group consensus. [less ▲]

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See detailla méthode conductive selon Petho
Battisti, Oreste ULg

Learning material (2012)

introduction et illustration par un film de la méthode conductive selon Petho, avec le film "je veux le faire tout seul"

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See detailReconstruction of a human mitochondrial complex I mutation in the unicellular green alga Chlamydomonas.
Larosa, Véronique ULg; Coosemans, Nadine ULg; Motte, Patrick ULg et al

in Plant Journal (The) (2012), 70

Defects in complex I (NADH:ubiquinone oxidoreductase) are the most frequent cause of human respiratory disorders. The pathogenicity of a given human mitochondrial mutation can be difficult to demonstrate ... [more ▼]

Defects in complex I (NADH:ubiquinone oxidoreductase) are the most frequent cause of human respiratory disorders. The pathogenicity of a given human mitochondrial mutation can be difficult to demonstrate because the mitochondrial genome harbors large numbers of polymorphic base changes that have no pathogenic significance. In addition, mitochondrial mutations are usually found in the heteroplasmic state, which could hide the biochemical effect of the mutation. We propose that the unicellular green alga Chlamydomonas could be used to study such mutations because (1) respiratory-deficient mutants are viable and mitochondrial mutations are found in the homoplasmic state, (2) transformation of the mitochondrial genome is feasible, (3) Chlamydomonas complex I is close to that of humans. To illustrate that, we have introduced a Leu157Pro substitution in the Chlamydomonas ND4 subunit of complex I of two different recipient strains by biolistic transformation, demonstrating that site-directed mutagenesis of the Chlamydomonas mitochondrial genome is possible. This substitution did not lead to any respiratory enzyme defect when it is present in the heteroplasmic state in a patient presenting chronic progressive external ophthalmoplegia. When present in the homoplasmic state in the alga, the mutation does not prevent the assembly of the 950 kDa whole complex I which conserves nearly all the NADH dehydrogenase activity of the peripheral arm. However, the NADH:duroquinone oxidoreductase activity is strongly reduced, suggesting that the substitution could affect ubiquinone fixation to the membrane domain. The in vitro defects are correlated in vivo with a decrease in dark respiration and growth rate. [less ▲]

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See detailA finite volume based data transfer method for remeshing. Application to metal forming problems
Bussetta, Philippe ULg; Ponthot, Jean-Philippe ULg

in Proceedings of the 18th International Symposium on Plasticity & Its Current Applications (2012, January)

The resolution of many nonlinear solid mechanical problems with the Finite Elements Method requires remeshing when very large deformations occur. The remeshing operation is divided into two parts: the ... [more ▼]

The resolution of many nonlinear solid mechanical problems with the Finite Elements Method requires remeshing when very large deformations occur. The remeshing operation is divided into two parts: the generation of the new mesh and the data transfer from the old to the new mesh. In dynamic plasticity problems, two kinds of fields have to be transferred: the first is defined thanks to the nodal values and the second one is defined at the integration points. These two kinds of fields are transferred thanks to an original computation of the Data Transfer Method based on the Finite Volume Elements. This method is compared to another one using Mortar Elements to solve metal forming problems. [less ▲]

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See detailÉtienne Klein, "Le Small Bang des nanotechnologies"
Thoreau, François ULg

in Esprit (Paris, France : 1932) (2012), 381

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See detailPersonality modulation of (un)conscious processing: Novelty seeking and performance following supraliminal and subliminal reward cues
Bustin, Gaëlle ULg; Quoidbach, Jordi; Hansenne, Michel ULg et al

Poster (2012, January)

This study provides evidence that personality traits associated with responsiveness to conscious reward cues also influence responsiveness to unconscious reward cues. Participants with low and high levels ... [more ▼]

This study provides evidence that personality traits associated with responsiveness to conscious reward cues also influence responsiveness to unconscious reward cues. Participants with low and high levels of Novelty Seeking (NS) performed updating tasks in which they could either gain 1 euro or 5 cents. Gains were presented either supraliminally or subliminally at the beginning of each trial. Results showed that low NS participants performed better in the high-reward than in the low-reward condition, whereas high NS participants’ performance did not differ between reward conditions. Interestingly, we found that low NS participants performed significantly better when rewards were presented unconsciously, whereas high NS participants’ performance did not differ whether reward cues were presented subliminally or supraliminally. Our findings highlight the necessity to take personality into account in unconscious cognition research. They also suggest that whether implicit and explicit motives have similar or complementary influences might be determined by individual differences. [less ▲]

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See detailInternet-Based Investing at the Edge of Chaos
Choffray, Jean-Marie ULg

E-print/Working paper (2012)

This paper presents a simple, seven-step approach, to surviving on World Street: an investment environment characterized by high frequency trading system; over leveraged shadow entities and hedge funds ... [more ▼]

This paper presents a simple, seven-step approach, to surviving on World Street: an investment environment characterized by high frequency trading system; over leveraged shadow entities and hedge funds; flash crashes, incompetent management, reverse merger frauds, dot bubble 2.0 IPOs and stealth central banks’ actions. Its goal is to help you design efficient investment strategies while protecting your assets. It is based on a personal research conducted over the last ten years, involving hundreds of observations, investment simulations and actual decisions. [less ▲]

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See detailA real-time assessment of the ship design complexity
Caprace, Jean-David ULg; Rigo, Philippe ULg

in Computer-Aided Design (2012), 44

The paper introduces an innovative complexity metric for passenger ships taking into account the shape complexity of steel parts, the assembly complexity and the material complexity. The goal is to ... [more ▼]

The paper introduces an innovative complexity metric for passenger ships taking into account the shape complexity of steel parts, the assembly complexity and the material complexity. The goal is to provide the designer with such information throughout the design process so that an efficient design is obtained at the first design run. Real-time assessment of complexity and quality measurements is rather imperative to ensure efficient and effective optimality search, and to allow real-time adjustment of requirements during the design. Application and validation on a real passenger ship show that the new method is effective in giving a complementary aid to decision process for ship designers. [less ▲]

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See detail(G)astronomie - Comète glacée
Nazé, Yaël ULg

Article for general public (2012)

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See detailRestructurations d'entreprises et reconversion territoriale. Vers une institutionnalisation adaptative.
Naedenoen, Frédéric ULg; Pichault, François ULg

in Revue Française de Gestion (2012), 38(n°220), 133-147

The usual way of analyzing the challenges of territorial governance in a restructuring context lies on a planning vision of industrial strategies: once the announcement is operated, a series of events ... [more ▼]

The usual way of analyzing the challenges of territorial governance in a restructuring context lies on a planning vision of industrial strategies: once the announcement is operated, a series of events will occur following a sequential path. Few territorial studies refer to emergent restructuring processes or even to dramatic strategic reorientations. By comparing the evolving practices of two territorial actors, directly concerned with the strategic jolts of the restructuring process undertaken by the ArcelorMittal steel group, this paper scrutinizes the conditions under which one of them seems to answer this changing context with more efficacy than the other. The emphasis is put on what we propose to call a process of ‘adaptive institutionalization”, in which the actor in charge of territorial governance is able to cope with contextual variations while maintaining the stakeholders involved. [less ▲]

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