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See detailClassical and Bayesian inference in neuroimaging : Theory
Friston, Karl J; Penny, W.; Phillips, Christophe ULg et al

in Neuroimage (2002), 16(2), 465-483

This paper reviews hierarchical observation models, used in functional neuroimaging, in a Bayesian light. It emphasizes the common ground shared by classical and Bayesian methods to show that conventional ... [more ▼]

This paper reviews hierarchical observation models, used in functional neuroimaging, in a Bayesian light. It emphasizes the common ground shared by classical and Bayesian methods to show that conventional analyses of neuroimaging data can be usefully extended within an empirical Bayesian framework. In particular we formulate the procedures used in conventional data analysis in terms of hierarchical linear models and establish a connection between classical inference and parametric empirical Bayes (PEB) through covariance component estimation. This estimation is based on an expectation maximization or EM algorithm. The key point is that hierarchical models not only provide for appropriate inference at the highest level but that one can revisit lower levels suitably equipped to make Bayesian inferences. Bayesian inferences eschew many of the difficulties encountered with classical inference and characterize brain responses in a way that is more directly predicated on what one is interested in. The motivation for Bayesian approaches is reviewed and the theoretical background is presented in a way that relates to conventional methods, in particular restricted maximum likelihood (ReML). This paper is a technical and theoretical prelude to subsequent papers that deal with applications of the theory to a range of important issues in neuroimaging. These issues include; (i) Estimating nonsphericity or variance components in fMRI time-series that can arise from serial correlations within subject, or are induced by multisubject (i.e., hierarchical) studies. (ii) Spatiotemporal Bayesian models for imaging data, in which voxels-specific effects are constrained by responses in other voxels. (iii) Bayesian estimation of nonlinear models of hemodynamic responses and (iv) principled ways of mixing structural and functional priors in EEG source reconstruction. Although diverse, all these estimation problems are accommodated by the PEB framework described in this paper. [less ▲]

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See detailCandidate locus for familial abdominal aortic aneurysms by genome-wide DNA linkage analysis
Shibamura, H.; Buxbaum, S.; Olson, J. M. et al

in Circulation (2002), 106(19, Suppl. S), 168

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See detailFirst report on the presence in France of a B-chromosome polymorphism in Apodemus flavicollis
Ramalhinho, M. G.; Libois, Roland ULg

in Mammalia (2002), 66(2), 300-303

Observation of B chromosomes in Apodemus flavicollis in France (Massif central)

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See detailIce-dynamic conditions of Shirase Glacier, Antarctica, inferred from ERS SAR interferometry
Pattyn, Frank; De Rauw, Dominique ULg

in Journal of Glaciology (2002), 48(163), 559-565

The surface velocity field of Shirase Glacier, a fast-flowing East Antarctic outlet glacier, is determined from ERS synthetic aperture radar (SAR) images by means of speckle tracking using phase ... [more ▼]

The surface velocity field of Shirase Glacier, a fast-flowing East Antarctic outlet glacier, is determined from ERS synthetic aperture radar (SAR) images by means of speckle tracking using phase correlation, a technique which matches small image kernels of two complex SAR images by maximization of the local coherence. Velocity estimates are used to calculate surface strain rates, which are then used to calculate the large-scale, vertically integrated force balance and to determine the major stress components resisting the driving stress. For the whole glacier system, the driving stress is largely balanced by the basal drag, but with contributions from lateral drag up to 15% of the driving stress at the grounding line. Longitudinal stress gradients have only local importance to the balance of forces, limited to an area of a few square kilometers near the grounding line, where they resist the driving stress. In the grounded part of the glacier, >90% of the total ice velocity is due to basal sliding. Comparison with a balance-flux distribution of the Antarctic ice sheet suggests that the glacier in the downstream part of the Shirase drainage basin is close to equilibrium, showing a slight negative imbalance. [less ▲]

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See detailWater fluxes at an ocean margin in the presence of a submarine canyon
Skliris, Nikolaos ULg; Hecq, Jean-Henri ULg; Djenidi, Salim ULg

in Journal of Marine Systems (2002), 32(1-3), 239-251

A 3-D, unsteady, nonlinear, high-resolution model is used to estimate shelf/slope exchanges through Calvi Canyon (NW Corsica, Mediterranean Sea) in various regimes of stratification and wind patterns. To ... [more ▼]

A 3-D, unsteady, nonlinear, high-resolution model is used to estimate shelf/slope exchanges through Calvi Canyon (NW Corsica, Mediterranean Sea) in various regimes of stratification and wind patterns. To evaluate the alongshore and cross-shore fluxes within the canyon area as well as the water exchanges between the canyon and Calvi Bay, volume transports are computed at the sides of two closed, interconnected boxes encompassing the canyon on the shelf and slope domains. Model results show that water transports between Calvi Bay and the open sea are determined by flow modifications in the canyon area. The mean horizontal flow deviates southwestward upstream of the canyon, generating an onshore transport in the western part of Calvi Bay. Within the canyon, the circulation is cyclonic and is responsible for an offshore transport downstream of the canyon and in the eastern part of the bay. The effect of stratification is shown to limit the vertical extent of the influence of canyon topography so that the alongshore flow above the canyon is quasi-undisturbed in strong stratified conditions, resulting in weak cross-shore exchange. Wind events are shown to be responsible for a strong increase of cross-shore transports between the bay and the canyon area. (C) 2002 Elsevier Science B.V All rights reserved. [less ▲]

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See detailDifferential sensitivity of two insect GABA-gated chloride channels to dieldrin, fipronil and picrotoxinin
Le Corronch, Hervé; Alix, Philippe ULg; Hue, B

in Journal of Insect Physiology (2002), 48

In the central nervous system of both vertebrates and invertebrates inhibitory neurotransmission is mainly achieved through activation of gamma-aminobutyric acid (GABA) receptors. Extensive studies have ... [more ▼]

In the central nervous system of both vertebrates and invertebrates inhibitory neurotransmission is mainly achieved through activation of gamma-aminobutyric acid (GABA) receptors. Extensive studies have established the structural and pharmacological properties of vertebrate GABA receptors. Although the vast majority of insect GABA-sensitive responses share some properties with vertebrate GABAA receptors, peculiar pharmacological properties of these receptors led us to think that several GABA-gated chloride channels are present in insects. We describe here the pharmacological properties of two GABA receptor subtypes coupled to a chloride channel on dorsal unpaired median (DUM) neurones of the adult male cockroach. Long applications of GABA induce a large biphasic hyperpolarization, consisting of an initial transient hyperpolarization followed by a slow phase of hyperpolarization that is not quickly desensitized. With GABA, the transient hyperpolarization is sensitive to picrotoxinin, fipronil and dieldrin whereas the slow response is insensitive to these insecticides.When GABA is replaced by muscimol and cis-4-aminocrotonic acid (CACA) a biphasic hyperpolarization consisting of an initial transient hyperpolarization followed by a sustained phase is evoked which is blocked by picrotoxinin and fipronil. Exposure to dieldrin decreases only the early phase of the muscimol and CACA-induced biphasic response, suggesting that two GABA-gated chloride channel receptor subtypes are present in DUM neurones. This study describes, for the first time, a dieldrin resistant component different to the dieldrin- and picrotoxinin-resistant receptor found in several insect species. [less ▲]

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See detailStripkritiek in Vlaanderen
Kempeneers, Michel; Meesters, Gert ULg

in Kreatief (2002), 36(2), 4-15

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See detailCryopreservation For The Elimination Of Cucumber Mosaic And Banana Streak Viruses From Banana (Musa Spp.)
Helliot, Bertrand; Panis, B.; Poumay, Y. et al

in Plant Cell Reports (2002), 20(12), 1117-1122

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See detailDetection Of Apple Chlorotic Leaf Spot Virus Using A 5 ' Nuclease Assay With A Fluorescent 3 ' Minor Groove Binder-Dna Probe
Vendrame, Marina; Kummert, Jean; Lepoivre, Philippe ULg et al

in Journal of Virological Methods (2002), 104(1), 99-106

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See detailRapid And Homogenous Detection Of Apple Stem Pitting Virus By Rt-Pcr And A Fluorogenic 3 ' Minor Groove Binder-Dna Probe
Salmon, Marc ULg; Vendrame, Marina; Kummert, Jean et al

in European Journal of Plant Pathology (2002), 108(8), 755-762

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See detailRevue bibliographique: les methodes chimiques d'identification et de classification des champignons.
Verscheure, M.; Lognay, Georges ULg; Marlier, M.

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2002), 6(3), 131-142

For few years, advancements of molecular methods and analytical techniques enabled scientists to realise a classification of microorganisms based on biochemical characteristics. This classification ... [more ▼]

For few years, advancements of molecular methods and analytical techniques enabled scientists to realise a classification of microorganisms based on biochemical characteristics. This classification, called chemotaxonomy, includes molecular methods and chemical methods which provide additional data and lead to a better identification and/or classification. [less ▲]

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See detailSpray pattern simulation model for standardisation of boom behaviour tests.
Lebeau, Frédéric ULg; Bouchat, X.; Ruter, R. et al

in Aspects of Applied Biology (2002), (66),

Simulation models of spray pattern are required for the dynamic behaviour assessment of sprayer booms. The reasons are their ease of use and their independence regarding variable operating conditions such ... [more ▼]

Simulation models of spray pattern are required for the dynamic behaviour assessment of sprayer booms. The reasons are their ease of use and their independence regarding variable operating conditions such as liquid properties and nozzle state, which interfere with the discrimination between various dynamic behaviours properties. Although such models have been developed for many decades, no international consensus has been reached on their use in a standardised test procedure. A consensual model is tested in the scope of standardisation specific needs. It uses ISO-5682/1 spray table measurements of the static distributions to compute three 2-D distribution at three heights using a filtered back-projection algorithm. These distributions are interpolated to generate a 3-D matrix of repartition at various heights. This 3-D matrix is used as nozzle distribution description in a dynamic distribution model where the dynamic distribution is computed as a summation of the static distribution at successive positions. The model kernel was found suitable to predict the repartition under a moving boom. [less ▲]

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See detailUtilisation du bootstrap pour les problèmes statistiques liés à l'estimation des paramètres.
Palm, Rodolphe ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2002), 6(3),

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See detailCréation d'un site Internet d'Evidence-Based Medicine.
Delvenne, Catherine ULg; Pasleau, Françoise ULg

in Médi-Sphère (2002), (67), 41-43

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See detailInsert'Prof. Pour un dispositif de formation favorisant une insertion réussie dans la vie professionnelle
Beckers, Jacqueline ULg; Andrianne, Sabine; Bourguignon, Luc et al

in Actes du 2e congrès des chercheurs en éducation (2002)

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See detailLa résolution des litiges transfrontaliers avec l'e-investisseur : questions choisies
Boularbah, Hakim ULg

in La protection de l'investisseur et de l'e-investisseur (2002)

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See detailColumnar defects acting as passive internal field detectors
Silhanek, Alejandro ULg; Civale, L.; Avila, M. A.

in Physical Review. B : Condensed Matter (2002), 65(17),

We have studied the angular dependence of the irreversible magnetization of several YBa2Cu3O7 and 2H-NbSe2 single crystals with columnar defects tilted off the c axis. At high magnetic fields, the ... [more ▼]

We have studied the angular dependence of the irreversible magnetization of several YBa2Cu3O7 and 2H-NbSe2 single crystals with columnar defects tilted off the c axis. At high magnetic fields, the irreversible magnetization M-i(Theta) exhibits a well-known maximum when the applied field is parallel to the tracks. As the field is decreased below Hsimilar to0.02H(c2), the peak shifts away from the tracks' direction toward either the c axis or the ab planes. We demonstrate that this shift results from the misalignment between the external and internal field directions due to the competition between anisotropy and geometry effects. [less ▲]

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See detailGeology, palaeobotany and palynology of the Northeastern part of the Ardenne, Belgium
Steemans, Philippe ULg; Vanguestaine, M.; Gerrienne, Philippe ULg

Book published by Paleopalyno. Paléobot. Micropal. (2002)

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See detailMPEG: Standards for Digital Video MPEG Activities in Belgium
Van Droogenbroeck, Marc ULg

in Revue HF (2002), 2

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