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See detailVariational Bayesian inversion of the equivalent current dipole model in EEG/MEG
Kiebel, S. J.; Daunizeau, J.; Phillips, Christophe ULg et al

in Neuroimage (2008), 39(2), 728-741

In magneto- and electroencephalography (M/EEG), spatial modelling of sensor data is necessary to make inferences about underlying brain activity. Most source reconstruction techniques belong to one of two ... [more ▼]

In magneto- and electroencephalography (M/EEG), spatial modelling of sensor data is necessary to make inferences about underlying brain activity. Most source reconstruction techniques belong to one of two approaches: point source models, which explain the data with a small number of equivalent current dipoles and distributed source or imaging models, which use thousands of dipoles. Much methodological research has been devoted to developing sophisticated Bayesian source imaging inversion schemes, while dipoles have received less such attention. Dipole models have their advantages; they are often appropriate summaries of evoked responses or helpful first approximations. Here, we propose a variational Bayesian algorithm that enables the fast Bayesian inversion of dipole models. The approach allows for specification of priors on all the model parameters. The posterior distributions can be used to form Bayesian confidence intervals for interesting parameters, like dipole locations. Furthermore, competing models (e.g., models with different numbers of dipoles) can be compared using their evidence or marginal likelihood. Using synthetic data, we found the scheme provides accurate dipole localizations. We illustrate the advantage of our Bayesian scheme, using a multi-subject EEG auditory study, where we compare competing models for the generation of the N100 component. (C) 2007 Elsevier Inc. All rights reserved. [less ▲]

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See detailEnjeux cognitifs de l’esquisse dans la littérature européenne du XIXe siècle
Stienon, Valérie ULg

in @nalyses : Revue de Critique et de Théorie Littéraire (2008)

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See detailSolar Concentrator
Habraken, Serge ULg; Defise, Jean-Marc ULg; Collette, Jean-Paul ULg

Patent (2008)

A combination of lens and mirror for solar concentration is presented.Collection efficiency, uniformity and compactness are the main goals

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See detailStochastic excitation of non-radial modes. I. High-angular-degree p modes
Belkacem, Kevin ULg; Samadi, R.; Goupil, Marie-José et al

in Astronomy and Astrophysics (2008), 478

Context: Turbulent motions in stellar convection zones generate acoustic energy, part of which is then supplied to normal modes of the star. Their amplitudes result from a balance between the efficiencies ... [more ▼]

Context: Turbulent motions in stellar convection zones generate acoustic energy, part of which is then supplied to normal modes of the star. Their amplitudes result from a balance between the efficiencies of excitation and damping processes in the convection zones. Aims: We develop a formalism that provides the excitation rates of non-radial global modes excited by turbulent convection. As a first application, we estimated the impact of non-radial effects on excitation rates and amplitudes of the high-angular-degree modes that are observed on the Sun. Methods: A model of stochastic excitation by turbulent convection was developed to compute the excitation rates and then successfully applied to solar radial modes. We generalise this approach to the case of non-radial global modes. This enables us to estimate the energy supplied to high-(l) acoustic modes. Qualitative arguments, as well as numerical calculations, are used to illustrate the results. Results: We find that non-radial effects for p modes are non-negligible: - For high-n modes (i.e. typically n > 3) and for high values of l, the power supplied to the oscillations depends on the mode inertia. - For low-n modes, independent of the value of l, the excitation is dominated by the non-radial components of the Reynolds stress term. Conclusions: Our numerical investigation of high-l p modes shows that the validity of the present formalism is limited to l < 500 due to the spatial separation of scale assumption. Thus, a model for very high-l p-mode excitation rates calls for further theoretical developments; however, the formalism is valid for solar g modes, which will be investigated in a paper in preparation. [less ▲]

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See detailHard X-ray emission from eta Carinae
Leyder, Jean-Christophe ULg; Walter, R.; Rauw, Grégor ULg

in Astronomy and Astrophysics (2008), 477

Context: If relativistic particle acceleration takes place in colliding-wind binaries, hard X-rays and gamma-rays are expected through inverse Compton emission, but to date these have never been ... [more ▼]

Context: If relativistic particle acceleration takes place in colliding-wind binaries, hard X-rays and gamma-rays are expected through inverse Compton emission, but to date these have never been unambiguously detected. Aims: To detect this emission, observations of eta Carinae were performed with INTEGRAL, leveraging its high spatial resolution. Methods: Deep hard X-ray images of the region of eta Car were constructed in several energy bands. Results: The hard X-ray emission previously detected by BeppoSax around eta Car originates from at least 3 different point sources. The emission of eta Car itself can be isolated for the first time, and its spectrum unambiguously analyzed. The X-ray emission of eta Car in the 22-100 keV energy range is very hard (Gamma ~= 1 ± 0.4) and its luminosity is 7 × 10^33 erg s^-1. Conclusions: The observed emission is in agreement with the predictions of inverse Compton models, and corresponds to about 0.1% of the energy available in the wind collision. eta Car is expected to be detected in the GeV energy range. [less ▲]

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See detailDistribution of the O[SUB]2[/SUB] infrared nightglow observed with VIRTIS on board Venus Express
Gérard, Jean-Claude ULg; Saglam, Adem ULg; Piccioni, G. et al

in Geophysical Research Letters (2008), 35

We present characteristics of the statistical horizontal distribution of the O[SUB]2[/SUB] infrared nightglow over most of the southern hemisphere observed with the VIRTIS instrument over a period ... [more ▼]

We present characteristics of the statistical horizontal distribution of the O[SUB]2[/SUB] infrared nightglow over most of the southern hemisphere observed with the VIRTIS instrument over a period spanning nearly 11 months of low solar activity. We show that the distribution is inhomogeneous with the regions of brightest emission reaching ~3 MegaRayleighs (MR) located at low latitude near and dawnward of the midnight meridian. The hemispherically averaged nadir brightness is 1.3 MR, in very good agreement with earlier ground based observations. We show that the dayside supply of O atoms is sufficient to produce the observed global O[SUB]2[/SUB] nightglow if approximately 50% of the dayside O production is carried to the nightside by the subsolar to antisolar global circulation. Limb profiles observed at northern mid-latitudes exhibit large intensity variations over short time periods. Calculations with a one-dimensional chemical diffusive model produce an airglow peak at 96 km, in agreement with the limb observations. The atomic oxygen density derived from the best fits to O[SUB]2[/SUB] airglow limb profiles reaches a maximum of 1.8-3.5 × 10[SUP]11[/SUP] cm[SUP]-3[/SUP] at 104 km. [less ▲]

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See detailL'astronomie dans le monde
Manfroid, Jean ULg

Article for general public (2008)

Vénus Express : une nouvelle vision de la météorologie vénusienne; Mercure et la sonde Messenger; Satellites de Saturne; Jets X solaires; Matériaux prébiotiques sur Titan; Systèmes planétaires jeunes ... [more ▼]

Vénus Express : une nouvelle vision de la météorologie vénusienne; Mercure et la sonde Messenger; Satellites de Saturne; Jets X solaires; Matériaux prébiotiques sur Titan; Systèmes planétaires jeunes; Naines blanches; Premières étoiles; Galaxies naines; H_3^+ extragalactique; H_3^+ extragalactique et planètes chaudes; [less ▲]

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See detailApproximations of Lovász extensions and their induced interaction index
Marichal, Jean-Luc; Mathonet, Pierre ULg

in Discrete Applied Mathematics (2008), 156(1), 11-24

The Lovasz extension of a pseudo-Boolean function f : (0, 1)(n) -> R is defined on each simplex of the standard triangulation of [0, 1](n) as the unique affine function (f) over cap : [0, 1](n) -> R that ... [more ▼]

The Lovasz extension of a pseudo-Boolean function f : (0, 1)(n) -> R is defined on each simplex of the standard triangulation of [0, 1](n) as the unique affine function (f) over cap : [0, 1](n) -> R that interpolates f at the n + 1 vertices of the simplex. Its degree is that of the unique multilinear polynomial that expresses f. In this paper we investigate the least squares approximation problem of an arbitrary Lovasz extension (f) over cap by Lovasz extensions of (at most) a specified degree. We derive explicit expressions of these approximations. The corresponding approximation problem for pseudo-Boolean functions was investigated by Hammer and Holzman [Approximations of pseudo-Boolean functions; applications to game theory, Z. Oper. Res. 36(1) (1992) 3-21] and then solved explicitly by Grabisch et al. [Equivalent representations of set functions, Math. Oper. Res. 25(2) (2000) 157-178], giving rise to an alternative definition of Banzhaf interaction index. Similarly we introduce a new interaction index from approximations of (f) over cap and we present some of its properties. It turns out that its corresponding power index identifies with the power index introduced by Grabisch and Labreuche [How to improve acts: an alternative representation of the importance of criteria in MCDM, Internat. J. Uncertain. Fuzziness Knowledge-Based Syst. 9(2) (2001) 145-157]. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailMyeloperoxidase Assay in Plasma and Peritoneal Fluid of Horses with Gastrointestinal Disease
Grulke, Sigrid ULg; Franck, Thierry ULg; Gangl, Monika et al

in Canadian Journal of Veterinary Research = Revue Canadienne de Recherche Vétérinaire (2008), 72(1), 37-42

Gastrointestinal disorders, especially strangulating intestinal obstructions, are still a major cause of illness and death in the horse. Circulating lipopolysaccharides may activate both neutrophils and ... [more ▼]

Gastrointestinal disorders, especially strangulating intestinal obstructions, are still a major cause of illness and death in the horse. Circulating lipopolysaccharides may activate both neutrophils and monocytes. The activated neutrophils release myeloperoxidase (MPO), a specific enzyme with strong oxidative activity. The aim of this study was to evaluate MPO concentrations in the plasma and peritoneal fluid (PF) of horses with colic and to check the hypothesis that these concentrations would be higher in a case of strangulating obstruction than in cases of nonstrangulating disease. By using a specific enzyme-linked immunosorbent assay for equine MPO, we determined the MPO concentrations in horses admitted to a clinic for colic. Horses with nonstrangulating or strangulating obstruction of the large intestine (NSLI or SLI), strangulating obstruction of the small intestine (SSI), or inflammatory bowel disease (IBD) were compared with healthy horses. The horses with SLI, SSI, or IBD had significantly higher MPO levels in plasma and PF than did those in the other 2 groups. The mean plasma level was significantly higher in the horses with NSLI than in the healthy horses. High MPO values in PF indicated necrotic bowel. These results show that neutrophil activation occurs during nonstrangulating and strangulating intestinal obstruction in horses and that the plasma and PF MPO concentrations may be a marker of the severity of the disease. [less ▲]

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See detailRêve et obsessions. Ambiguïté narrative et thèmes récurrents dans l’œuvre de Blutch
Paques, Frédéric ULg

in 9e Art : Les Cahiers du Musée de la Bande Dessinée (2008), 14(janvier 2008),

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See detailPotentiel thérapeutique du coenzyme Q10
Pincemail, Joël ULg; Defraigne, Jean-Olivier ULg

in Journal de Cardiologie [= JDC] = Tijdschrift voor Cardiologie [= TVC] (2008), 1

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See detailCombining Ionosonde and GPS TEC Data to Assess NeQuick Formulation
Bidaine, Benoît ULg

Report (2008)

The main topic which was investigated during the mission is related to the validation of the NeQuick model using different data sets. The discussions were based on former work dealing with the comparison ... [more ▼]

The main topic which was investigated during the mission is related to the validation of the NeQuick model using different data sets. The discussions were based on former work dealing with the comparison of the first version of the model recommended by the ITU-R and its second version recently published. In addition the NeQuick formulation and its physical behaviour were discussed considering the bottomside and topside representations and the interaction between both. This will constitute the basis for future investigation of ingestion techniques using NeQuick as well as the ionospheric correction algorithm for Galileo single frequency users. [less ▲]

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See detailLe partenariat public/privé dans le monde de l'école...
Grignard, Sophie ULg

in Education Santé (2008), 230

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See detailMidsagittal Jaw Movement Analysis for the Scoring of Sleep Apneas and Hypopneas
Senny, Frédéric ULg; Destiné, Jacques ULg; Poirrier, Robert ULg

in IEEE Transactions on Biomedical Engineering (2008), 55(1), 87-95

Given the importance of the detection and classification of sleep apneas and hypopneas (SAHs) in the diagnosis and the characterization of the SAH syndrome, there is a need for a reliable noninvasive ... [more ▼]

Given the importance of the detection and classification of sleep apneas and hypopneas (SAHs) in the diagnosis and the characterization of the SAH syndrome, there is a need for a reliable noninvasive technique measuring respiratory effort. This paper proposes a new method for the scoring of SAHs based on the recording of the midsagittal jaw motion (MJM, mouth opening) and on a dedicated automatic analysis of this signal. Continuous wavelet transform is used to quantize respiratory effort from the jaw motion, to detect salient mandibular movements related to SAHs and to delineate events which are likely to contain the respiratory events. The classification of the delimited events is performed using multilayer perceptrons which were trained and tested on sleep data from 34 recordings. Compared with SAHs scored manually by an expert, the sensitivity and specificity of the detection were 86.1% and 87.4%, respectively. Moreover, the overall classification agreement in the recognition of obstructive, central, and mixed respiratory events between the manual and automatic scorings was 73.1%. The MJM signal is hence a reliable marker of respiratory effort and allows an accurate detection and classification of SAHs. [less ▲]

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See detailThe Hazar pull-apart along the East Anatolian Fault: Structure and active deformation
Hubert, Aurelia ULg; Garcia, D; Moernaut, J et al

Conference (2008, January)

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See detailHerbe, diguettes, pesticides et pomme de terre
Maugnard, Alexandre; Bodson, Bernard ULg; Goffart, Jean-Pierre et al

in Phytoma : La Défense des Végétaux (2008), 611

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See detailLes landes et pelouses sur sable du Brabant sablo-limoneux (Deuxième partie)
Taymans, Julien ULg; Mahy, Grégory ULg

in Parcs & Réserves (2008), 62(4), 4-12

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See detailEvidence for a Role of Early Oestrogens in the Central Processing of Sexually Relevant Olfactory Cues in Female Mice
Pierman, S.; Douhard, Quentin ULg; Bakker, Julie ULg

in European Journal of Neuroscience (2008), 27(2), 423-31

We previously found that female aromatase knockout (ArKO) mice showed less investigation of socially relevant odours as well as reduced sexual behaviour. We now ask whether these behavioural deficits ... [more ▼]

We previously found that female aromatase knockout (ArKO) mice showed less investigation of socially relevant odours as well as reduced sexual behaviour. We now ask whether these behavioural deficits might be due to an inadequate processing of odours in female ArKO mice. Therefore, we exposed female ArKO mice to same- and opposite-sex urinary odours and determined the expression of the immediate early gene c-Fos along the main and accessory olfactory projection pathways. We included ArKO males in the present study as we previously observed that they show female-typical detection thresholds of urinary odours, suggesting a role for perinatal oestrogens in these behavioural responses. No sex or genotype differences were observed in the olfactory bulb after urine exposure. By contrast, sex differences in c-Fos responses were observed in wild-type (WT) mice following exposure to male urine in the more central regions of the olfactory pathway; only WT females showed a significant Fos induction in the amygdala, central medial pre-optic area and ventromedial hypothalamus. However, ArKO females did not show a c-Fos response to male odours in the ventromedial hypothalamus, suggesting that the processing of male odours is affected in ArKO females and thus that oestrogens may be necessary for the development of neural responses to sexually relevant odours in female mice. By contrast, c-Fos responses to either male or oestrous female urine were very similar between ArKO and WT males, pointing to a central role of androgen vs. oestrogen signalling in the male circuits that control olfactory investigation and preferences. [less ▲]

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