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See detailFe-2(II)(PO4)(OH), a synthetic analogue of wolfeite
Hatert, Frédéric ULg

in Acta Crystallographica Section C-Crystal Structure Communications (2007), 63(Part 12), 119-121

This paper reports the hydrothermal synthesis and crystal structure refinement of diiron(II) phosphate hydroxide, Fe-2(II)(PO4)(OH), obtained at 1063 K and 2.5 GPa. This phosphate is the synthetic ... [more ▼]

This paper reports the hydrothermal synthesis and crystal structure refinement of diiron(II) phosphate hydroxide, Fe-2(II)(PO4)(OH), obtained at 1063 K and 2.5 GPa. This phosphate is the synthetic analogue of the mineral wolfeite, and has a crystal structure topologically identical to those of minerals of the triplite-triploidite group. The complex framework contains edge-and corner-sharing FeO4(OH) and FeO4(OH)(2) polyhedra, linked via corner-sharing to the PO4 tetrahedra (average P-O distances are between 1.537 and 1.544 angstrom). Four five-coordinated Fe sites are at the centers of distorted trigonal bipyramids (average Fe-O distances are between 2.070 and 2.105 angstrom), whereas the coordination environments of the remaining Fe sites are distorted octahedra (average Fe-O distances are between 2.146 and 2.180 angstrom). The Fe-O distances are similar to those observed in natural Mg-rich wolfeite, except for two Fe-O bond distances, which are significantly longer in synthetic Fe-2(2+) (PO4)(OH). [less ▲]

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See detailObservations and asteroseismic analysis of the rapidly pulsating hot B subdwarf PG 0911+456
Randall, Suzanna K.; Green, Elizabeth M.; Van Grootel, Valérie ULg et al

in Astronomy and Astrophysics (2007), 476

Aims:The principal aim of this project is to determine the structural parameters of the rapidly pulsating subdwarf B star PG 0911+456 from asteroseismology. Our work forms part of an ongoing programme to ... [more ▼]

Aims:The principal aim of this project is to determine the structural parameters of the rapidly pulsating subdwarf B star PG 0911+456 from asteroseismology. Our work forms part of an ongoing programme to constrain the internal characteristics of hot B subdwarfs with the long-term goal of differentiating between the various formation scenarios proposed for these objects. So far, a detailed asteroseismic interpretation has been carried out for 6 such pulsators, with apparent success. First comparisons with evolutionary theory look promising, however it is clear that more targets are needed for meaningful statistics to be derived. Methods: The observational pulsation periods of PG 0911+456 were extracted from rapid time-series photometry using standard Fourier analysis techniques. Supplemented by spectroscopic estimates of the star's mean atmospheric parameters, they were used as a basis for the “forward modelling” approach in asteroseismology. The latter culminates in the identification of one or more “optimal” models that can accurately reproduce the observed period spectrum. This naturally leads to an identification of the oscillations detected in terms of degree ℓ and radial order k, and infers the structural parameters of the target. Results: The high S/N low- and medium resolution spectroscopy obtained led to a refinement of the atmospheric parameters for PG 0911+456, the derived values being T_eff = 31 940 ± 220 K, log g = 5.767 ± 0.029, and log He/H = -2.548 ± 0.058. From the photometry it was possible to extract 7 independent pulsation periods in the 150-200 s range with amplitudes between 0.05 and 0.8% of the star's mean brightness. There was no indication of fine frequency splitting over the 68-day time baseline, suggesting a very slow rotation rate. An asteroseismic search of parameter space identified several models that matched the observed properties of PG 0911+456 well, one of which was isolated as the “optimal” model on the basis of spectroscopic and mode identification considerations. All the observed pulsations are identified with low-order acoustic modes with degree indices ℓ = 0,1,2 and 4, and match the computed periods with a dispersion of only 0.26%, typical of the asteroseismological studies carried out to date for this type of star. The inferred structural parameters of PG 0911+456 are T_eff = 31 940 ± 220 K (from spectroscopy), log {g} = 5.777 ± 0.002, Mast/Msun = 0.39 ± 0.01, log{M_env/Mast} = -4.69 ± 0.07, R/Rsun = 0.133 ± 0.001 and L/Lsun = 16.4 ± 0.8. We also derive the absolute magnitude MV = 4.82 ± 0.04 and a distance d = 930.3 ± 27.4 pc. [less ▲]

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See detailImplementation and Preliminary Evaluation of an ISP-Driven Informed Path Selection
Saucez, Damien; Donnet, Benoît ULg; Bonaventure, Olivier

in ACM CoNEXT conference (2007, December)

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See detailStabilization of Collective Motion in Three Dimensions : A Consensus Approach
Scardovi, Luca; Leonard, Naomi; Sepulchre, Rodolphe ULg

in Proceedings of 46th IEEE Conference on Decision and Control (2007, December)

This paper proposes a methodology to stabilize relative equilibria in a model of identical, steered particles moving in three- dimensional Euclidean space. Exploiting the Lie group structure of the ... [more ▼]

This paper proposes a methodology to stabilize relative equilibria in a model of identical, steered particles moving in three- dimensional Euclidean space. Exploiting the Lie group structure of the resulting dynamical system, the stabilization problem is reduced to a consensus problem on the Lie algebra. The resulting equilibria correspond to parallel, circular and helical formations. We rst derive the stabilizing control laws in the presence of all-to-all communication. Providing each agent with a consensus estimator, we then extend the results to a general setting that allows for unidirectional and time-varying communication topologies. [less ▲]

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See detailLe financement public des cultes et de la laïcité
Husson, Jean-François ULg

in Politique : Revue de Débats (2007), (52), 14-17

This article summarizes the public financing of religious and philosophical communities in Belgium. It discusses the way theses means are shared and the future of this model.

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See detailPredatory boreholes in Tournaisian (Lower Carboniferous) spiriferid brachiopods
Mottequin, Bernard ULg; Sevastopulo, George

in Budd, G. E.; Streng, M.; Daley, A. C. (Eds.) et al Programme with abstracts of the 51st Palaeontological Association Annual Meeting (2007, December)

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See detailQuestions de didactique des langues étrangères, du FLE (cycle de conf.)
Defays, Jean-Marc ULg

Scientific conference (2007, December)

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See detailAutonomous rigid body attitude synchronization
Sarlette, Alain ULg; Sepulchre, Rodolphe ULg; Leonard, Naomi

in Proceedings of the 46th IEEE Conference on Decision and Control (2007, December)

This paper studies some extensions to the decentralized attitude synchronization of identical rigid bodies. Considering fully actuated Euler equations, the communication links between the rigid bodies are ... [more ▼]

This paper studies some extensions to the decentralized attitude synchronization of identical rigid bodies. Considering fully actuated Euler equations, the communication links between the rigid bodies are limited and the available information is restricted to relative orientations and angular velocities. In particular, no leader nor external reference dictates the swarm's behavior. The control laws are derived using two classical approaches of nonlinear control - tracking and energy shaping. This leads to a comparison of two corresponding methods which are currently considered for distributed synchronization - consensus and stabilization of mechanical systems with symmetries. [less ▲]

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See detailLégende de la Carte Numérique des Sols de Wallonie - version 2
Bah, Boubacar Billo ULg; Legrain, Xavier ULg; Engels, Patrick ULg et al

Book published by Unité de Science du Sol - GxABT - ULg - 2ème éd. revue et corrigée (2007)

Cette synthèse commente la structure et le contenu de la légende de la Carte Numérique des Sols de Wallonie (CNSW), réalisée dans le cadre du Projet de Cartographie Numérique des Sols de Wallonie (PCNSW).

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See detailAn Arbitrary Lagrangian Eulerian Formulation for the Numerical Simulation of Forming Processes
Boman, Romain ULg; Papeleux, Luc ULg; Ponthot, Jean-Philippe ULg

in International Workshop 2007: Advancements in Design Optimization of Materials, Structures and Mechanical Systems (2007, December)

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See detailProgresse-t-on en enseignement des langues étrangères?
Defays, Jean-Marc ULg

Scientific conference (2007, December)

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See detailLa circonscription fédérale : un placebo administré à un malade incurable?
Bouhon, Frédéric ULg

E-print/Working paper (2007)

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See detailIntussen aan de kersttafel...
Ozer, Pierre ULg; Perrin, Dominique ULg

Article for general public (2007)

De afgelopen weken heb ik de reclamefolders van mijn dichtstbijzijnde hypermarkt uitgeplozen om een fijn dineetje samen te stellen. Hierna volgt het resultaat voor acht personen, met tussen haakjes het ... [more ▼]

De afgelopen weken heb ik de reclamefolders van mijn dichtstbijzijnde hypermarkt uitgeplozen om een fijn dineetje samen te stellen. Hierna volgt het resultaat voor acht personen, met tussen haakjes het aantal kilometers dat elk ingrediënt heeft afgelegd om naar België te komen en de hoeveelheid CO2 in kilogram die het transport geproduceerd heeft. Ik heb vooral ingrediënten gekozen die met het vliegtuig worden aangevoerd, want luchttransport produceert gemiddeld zestig keer meer CO2 dan vervoer over zee. [less ▲]

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See detailIon Beam Induced Luminescence & Cultural Heritage
Calvo Del Castillo, Helena ULg

Scientific conference (2007, December)

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See detailNoël en famille ou 15 litres de pétrole
Ozer, Pierre ULg; Perrin, Dominique ULg

Article for general public (2007)

La semaine précédant Noël, j’ai décortiqué les publicités de mon hypermarché le plus proche pour préparer le repas familial tant attendu. Et voici ce que j’ai pu concocter pour huit personnes avec, entre ... [more ▼]

La semaine précédant Noël, j’ai décortiqué les publicités de mon hypermarché le plus proche pour préparer le repas familial tant attendu. Et voici ce que j’ai pu concocter pour huit personnes avec, entre parenthèses, les kilomètres parcourus entre le pays de production et la Belgique ainsi que les kilogrammes de CO2 émis uniquement pour le transport aérien intercontinental de ces produits achetés. L’analyse se focalise sur le transport par voie aérienne puisque celui-ci émet, en moyenne, 60 fois plus de CO2 que le transport par voie maritime. [less ▲]

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See detailApproche ethnopharmacologique de plantes utilisées en médecine traditionnelle au Cambodge dans le traitement des maladies infectieuses, des fièvres et du paludisme
Cheng, S. K.; Chea, Aun; Hout, Sothera et al

in Ethnopharmacologia (2007), 40

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See detailEndometrial vessel maturation in women exposed to levonorgestrel-releasing intrauterine system for a short or prolonged period of time
Ravet, Stéphanie ULg; Labied, Soraya ULg; Blacher, Silvia ULg et al

in Human Reproduction (2007), 22(12), 3084-3091

BACKGROUND: Levonorgestrel-releasing intrauterine system (LNG-IUS), although inserted to reduce heavy menstruation, causes irregular early transient bleeding. The objective of the study was to document ... [more ▼]

BACKGROUND: Levonorgestrel-releasing intrauterine system (LNG-IUS), although inserted to reduce heavy menstruation, causes irregular early transient bleeding. The objective of the study was to document quantitative changes in endometrial vessels of short- (< or =3 months) and long-term (> or =12 months) LNG users. The area, density and maturation of endometrial vessels were quantified in 19 endometrial biopsies of women with LNG-IUS and in 10 normally ovulating patients during mid-luteal phase. METHODS: Vessel maturation was evaluated by double immunostaining using anti-von Willebrand factor (endothelial cell marker) and anti-alpha Smooth Muscle Actin (vascular smooth muscle cells) antibodies. Vessel area, number and density were quantified with a novel computer-assisted image analysis system. RESULTS: Endometrium exposed to LNG-IUS for 1-3 months displayed a 11.5-fold increase in small naked vessel number. The partially mature vessel (alphaSMA partially positive) number increased six times. After long-term LNG-IUS treatment, the immature and partially mature vessel number remained four times higher than in the control group. Vessel area and density also increased dramatically in a time-dependent pattern with LNG-IUS use. CONCLUSIONS: Levonorgestrel affects blood vessel number, area, density and maturation in a time-dependent pattern that may explain the early transient increase in breakthrough bleeding with the LNG-IUS. [less ▲]

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