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See detailJupiter’s polar auroral emissions-signatures of magnetic reconnection
Radioti, Aikaterini ULg; Gérard, Jean-Claude ULg; Grodent, Denis ULg et al

Conference (2007, August 23)

The polar auroral emissions at Jupiter can be divided into three regions fixed in mag- netic local time: the dawnside dark region, the poleward swirl region and the duskside active region in which flares ... [more ▼]

The polar auroral emissions at Jupiter can be divided into three regions fixed in mag- netic local time: the dawnside dark region, the poleward swirl region and the duskside active region in which flares and arc-like features are observed. Previous studies re- lated the polar emissions to the solar wind driven Dungey cycle and Vasyliunas flow cycle. Based on HST STIS and ACS images we study extensively the time variations of the morphology and brightness of various polar auroral features as well as their duration and reoccurrence. We magnetically map their location in the equatorial plane and we compare their spatial size and time scales with the reconnection events taking place in the Jovian magnetotail. We discuss the possibility that some polar auroral features are signatures of magnetic reconnection. [less ▲]

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See detailUsing survey data to resolve the exchange risk exposure puzzle
Muller, Aline ULg; Jongen, Ron; Verschoor, Willem

Conference (2007, August 22)

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See detailDevelopment and Layout of a ACC-System by means of Evolutionary Algorithms
Christen, Fréderic ULg

Scientific conference (2007, August 22)

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See detailDe genegeerde kunst
Meesters, Gert ULg

Article for general public (2007)

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See detailCost-benefit analysis of mass vaccination campaign against H5N1 in small scale production systems in Vietnam. Part I: Economical results in Long An province
Phan Dang, Thang ULg; Stéphanie Desvaux; Vu Dinh Ton et al

Poster (2007, August 19)

Highly Pathogenic Avian Influenza (HPAI) caused by H5N1 virus has become endemic in some developing countries and millions of birds have been culled with large economical and sociological impacts. Since ... [more ▼]

Highly Pathogenic Avian Influenza (HPAI) caused by H5N1 virus has become endemic in some developing countries and millions of birds have been culled with large economical and sociological impacts. Since the end of the first vaccination campaign in Vietnam limited outbreaks in non-vaccinated domestic poultry have been reported. However, the virus is still circulating as confirmed by routine surveillance programs. Vaccination is a useful tool to be used to eradicate the disease, but the cost-benefit impact of different strategy needs first to be addressed at local level, where implementation is decided. The aim of this study was to evaluate the cost-benefit impact of Vietnam mass vaccination program at local level. This poster presents the first step in the cost-benefit analysis: the partial economical analysis of the vaccination within Vietnam provinces. Only the results in Long An province (South) are presented here. [less ▲]

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See detailElectrografting method for forming and regulating a strong adherent nanostructured polymer coating
Jérôme, Robert ULg; Jérôme, Christine ULg; Serwas, Harry ULg et al

Patent (2007)

Electrografting method for forming and regulating a strongly adherent nanostructured polymer coating onto an electro-conductive surface profile characterized in that the surface profile is regulated by ... [more ▼]

Electrografting method for forming and regulating a strongly adherent nanostructured polymer coating onto an electro-conductive surface profile characterized in that the surface profile is regulated by electrodeposition of nanometre- and/or micrometre-scale nuclei onto the surface profile prior to or simultaneously to the formation of the polymer coating. [less ▲]

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See detailArchimedean copula estimation using Bayesian splines smoothing techniques
Lambert, Philippe ULg

in Computational Statistics & Data Analysis (2007), 51(12), 6307-6320

Copulas enable to specify multivariate distributions with given marginals. Various parametric proposals were made in the literature for these quantities, mainly in the bivariate case. They can be ... [more ▼]

Copulas enable to specify multivariate distributions with given marginals. Various parametric proposals were made in the literature for these quantities, mainly in the bivariate case. They can be systematically derived from multivariate distributions with known marginals, yielding e.g. the normal and the Student copulas. Alternatively, one can restrict his/her interest to a sub-family of copulas named Archimedean. They are characterized by a strictly decreasing convex function on (0, 1) which tends to +infinity at 0 (when strict) and which is 0 at 1. A ratio approximation of the generator and of its first derivative using B-splines is proposed and the associated parameters estimated using Markov chains Monte Carlo methods. The estimation is reasonably quick. The fitted generator is smooth and parametric. The generated chain(s) can be used to build "credible envelopes" for the above ratio function and derived quantities such as Kendall's tau, posterior predictive probabilities, etc. Parameters associated to parametric models for the marginals can be estimated jointly with the copula parameters. This is an interesting alternative to the popular two-step procedure which assumes that the regression parameters are fixed known quantities when it comes to copula parameter(s) estimation. A simulation study is performed to evaluate the approach. The practical utility of the method is illustrated by a basic analysis of the dependence structure underlying the diastolic and the systolic blood pressures in male subjects. (C) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailHerstellung von neuen strahlenhärtenden Bindemitteln
Detrembleur, Christophe ULg; Weikard, Jan; Greszta-Frank, Dorota et al

Patent (2007)

Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung neuartiger Bindemittel, die unter Einwirkung aktinischer Strahlung mit ethylenisch ungesättigten Verbindungen unter Polymerisation ... [more ▼]

Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung neuartiger Bindemittel, die unter Einwirkung aktinischer Strahlung mit ethylenisch ungesättigten Verbindungen unter Polymerisation reagierende Gruppen und gegebenenfalls auch gegenüber Isocyanaten reaktive Gruppen aufweisen, sowie deren Verwendung in Beschichtungsmitteln. [less ▲]

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See detailCrystal structure of the Bacillus subtilis penicillin-binding protein 4a, and its complex with a peptidoglycan mimetic peptide
Sauvage, Eric ULg; Duez, Colette ULg; Herman, Raphaël ULg et al

in Journal of Molecular Biology (2007), 371(2), 528-539

The genome of Bacillus subtilis encodes 16 penicillin-binding proteins (PBPs) involved in the synthesis and/or remodelling of the peptidoglycan during the complex life cycle of this sporulating Gram ... [more ▼]

The genome of Bacillus subtilis encodes 16 penicillin-binding proteins (PBPs) involved in the synthesis and/or remodelling of the peptidoglycan during the complex life cycle of this sporulating Gram-positive rod-shaped bacterium. PBP4a (encoded by the dacC gene) is a low-molecular mass PBP clearly exhibiting in vitro DD-carboxypeptidase activity. We have solved the crystal structure of this protein alone and in complex with a peptide (D-alpha'-aminopymelyl-epsilon-D-alanyl-D-alanine) that mimics the C-terminal end of the Bacillus peptidoglycan stem peptide. PBP4a is composed of three domains: the penicillin-binding domain with a fold similar to the class A 13-lactamase structure and two domains inserted between the conserved motifs 1 and 2 characteristic of the penicillin-recognizing enzymes. The soaking of PBP4a in a solution Of D-alpha-aminopymelyl-epsilon-D-alanyl-D-alanine resulted in an adduct between PBP4a and a D-alpha-aminopimelyl-epsilon-D-alanine dipeptide and an unbound D-alanine, i.e. the products of acylation of PBP4a by D-alpha-aminopymelyl-epsilon-D-alanyl-D-alanine with the release of a D-alanine. The adduct also reveals a binding pocket specific to the diaminopimelic acid, the third residue of the peptidoglycan stem pentapeptide of B. subtilis. This pocket is specific for this class of PBPs. (C) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailAuroral streamers and magnetic flux closure
Hubert, Benoît ULg; Kauristie, K.; Amm, O. et al

in Geophysical Research Letters (2007), 34(15),

On 7 December 2000 at 2200 UT an auroral streamer was observed to develop above Scandinavia with the IMAGE-FUV global imagers. The ionospheric equivalent current deduced from the MIRACLE-IMAGE ... [more ▼]

On 7 December 2000 at 2200 UT an auroral streamer was observed to develop above Scandinavia with the IMAGE-FUV global imagers. The ionospheric equivalent current deduced from the MIRACLE-IMAGE Scandinavian ground-based network of magnetometers is typical of a substorm-time streamer. Observations of the proton aurora using the SI12 imager onboard the IMAGE satellite are combined with measurements of the ionospheric convection obtained by the SuperDARN radar network to compute the dayside merging and nightside flux closure rates. On the basis of this and other similar events, it is found that auroral streamers appear during the period of most intense flux closure in the magnetotail, most often shortly after substorm onset. The ionospheric convection velocity, as measured by SuperDARN, appears to be reduced in the vicinity of the streamer, suggesting de-coupling of magnetospheric and ionospheric plasma flows in the region of enhanced ionospheric conductance. [less ▲]

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See detailNiedrigviskose allophanate mit aktinisch härtbaren gruppen
Detrembleur, Christophe ULg; Weikard, Jan; Greszta-Franz, Dorota et al

Patent (2007)

Die vorliegende Erfindung betrifft niedrigviskose Umsetzungsprodukte von Polyisocyanaten, die aktivierte unter Einwirkung aktinischer Strahlung mit ethylenisch ungesättigten Verbindungen unter ... [more ▼]

Die vorliegende Erfindung betrifft niedrigviskose Umsetzungsprodukte von Polyisocyanaten, die aktivierte unter Einwirkung aktinischer Strahlung mit ethylenisch ungesättigten Verbindungen unter Polymerisation reagierende Gruppen enthalten, ein Verfahren zu ihrer Herstellung sowie deren Verwendung in Beschichtungsmitteln. [less ▲]

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See detailVotre assiette a fait le tour du monde
Ozer, Pierre ULg

Article for general public (2007)

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See detailLattice of subalgebras in the finitely generated varieties of MV-algebras
Teheux, Bruno ULg

in Discrete Mathematics (2007), 307(17-18), 2261-2275

In this paper, we use the theory of natural duality to study subalgebra lattices in the finitely generated varieties of MV-algebras, With this tool, we obtain the dual atomicity of these lattices, and ... [more ▼]

In this paper, we use the theory of natural duality to study subalgebra lattices in the finitely generated varieties of MV-algebras, With this tool, we obtain the dual atomicity of these lattices, and characterize the members of these varieties in which every subalgebra is an intersection of maximal subalgebras. Then, we determine the algebras that have a modular or distributive lattice of subalgebras. [less ▲]

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See detailUn coach pour nos entreprises
Nondonfaz, Robert ULg

Article for general public (2007)

Nécessité pour chaque entreprise de se faire "coacher" pour repréciser les pistes d'amélioration

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See detailNonaqueous electrokinetic chromatography-electrospray ionization mass spectrometry using anionic cyclodextrins
Mol, Roelof; Servais, Anne-Catherine ULg; Fillet, Marianne ULg et al

in Journal of Chromatography. A (2007), 1159(1-2), 51-57

The set-up of an on-line method for coupling nonaqueous electrokinetic chromatography (NAEKC) and electrospray ionization mass spectrometry (ESI-MS) is presented. It allows the use of the single-isomer ... [more ▼]

The set-up of an on-line method for coupling nonaqueous electrokinetic chromatography (NAEKC) and electrospray ionization mass spectrometry (ESI-MS) is presented. It allows the use of the single-isomer derivative anionic cyclodextrins heptakis(2,3-di-O-methyl-6-O-sulfo)-beta-cyclodextrin (HDMS-beta-CD) and heptakis(2.3-di-O-acetyl-6-O-sulfo)-beta-cyclodextrin (HDAS-beta-CD) for chiral and achiral separations of positively charged analytes. The effect of the cyclodextrins (CDs) on the MS signal intensities of model compounds was studied. When a voltage is applied over the CE capillary, the overall mobility of the CDs is towards the inlet vial preventing CDs from entering the ion source. However, the sodium counter ions of the CDs still enter the ion source and appeared to cause ionization suppression. Nevertheless, significant analyte signals could still be detected with detection limits in the sub-mu g/ml. System parameters such as sheath liquid composition and flow rate, nebulizing gas pressure, capillary position in the sprayer and the drying gas flow and temperature were studied and optimized. The selection of a relatively low nebulizing gas pressure appeared to be important to achieve optimum sensitivity. The chiral selectivity of the NAEKC-ESI-MS system could be improved by addition of camphorsulfonate to the background electrolyte. Using mixtures of drugs and drug-related compounds, the NAEKC-ESI-MS system is shown to offer potential for (chiral) drug profiling. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailThe field high-amplitude SX Phoenicis variable BL Camelopardalis: results from a multisite photometric campaign. I. Pulsation
Rodríguez, E.; Fauvaud, S.; Farrell, J. A. et al

in Astronomy and Astrophysics (2007), 471

Context: BL Cam is an extreme metal-deficient field high-amplitude SX Phe-type variable where a very complex frequency spectrum is detected, with a number of independent nonradial modes excited, unusual ... [more ▼]

Context: BL Cam is an extreme metal-deficient field high-amplitude SX Phe-type variable where a very complex frequency spectrum is detected, with a number of independent nonradial modes excited, unusual among the high-amplitude pulsators in the Lower Classical Instability Strip. Aims: An extensive and detailed study has been carried out to investigate the pulsational content and properties of this object. Methods: The analysis is based on 283 h of CCD observations obtained in the Johnson V filter, during a long multisite photometric campaign carried out along the Northern autumn-winter of 2005-2006. Additionally, multicolour BI photometry was also collected to study the phase shifts and amplitude ratios, between light curves obtained in different filters, for modal discrimination of the main excited modes. Results: The detailed frequency analysis revealed a very rich and dense pulsational content consisting of 25 significant peaks, 22 of them corresponding to independent modes: one is the already known main periodicity f[SUB]0[/SUB] = 25.5765 cd[SUP]-1[/SUP] (Delta V = 153 mmag) and the other 21 are excited modes showing very small amplitudes. Some additional periodicities are probably still remaining in the residuals. This represents the most complex spectrum ever detected in a high-amplitude pulsator of this type. The majority of the secondary modes suspected from earlier works are confirmed here and, additionally, a large number of new peaks are detected. The amplitude of the main periodicity f[SUB]0[/SUB] seems to be stable during decades, but the majority of the secondary modes show strong amplitude changes from one epoch to another. The suspected fundamental radial nature of the main periodicity of BL Cam is confirmed, while the secondary peak f[SUB]1[/SUB] = 25.2523 cd[SUP]-1[/SUP] is identified as a nonradial mixed mode g[SUB]4[/SUB] with l = 1. The radial double-mode nature, claimed by some authors for the main two frequencies of BL Cam, is not confirmed. Nevertheless, the frequency f[SUB]6[/SUB] = 32.6464 cd[SUP]-1[/SUP] could correspond to the first radial overtone. [less ▲]

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See detailRevised instability domains of SPB and beta Cephei stars
Miglio, Andrea ULg; Montalban Iglesias, Josefa ULg; Dupret, Marc-Antoine ULg

in Communications in Asteroseismology (2007), 151

The excitation of pulsation modes in beta Cephei and Slowly Pulsating B stars is known to be very sensitive to opacity changes in the stellar interior where T Ë 2 × 10[SUP]5[/SUP] K. In this region ... [more ▼]

The excitation of pulsation modes in beta Cephei and Slowly Pulsating B stars is known to be very sensitive to opacity changes in the stellar interior where T Ë 2 × 10[SUP]5[/SUP] K. In this region differences in opacity up to Ë 50% can be induced by the choice between OPAL and OP opacity tables, and between two different metal mixtures (Grevesse & Noels 1993 and Asplund et al. 2005). We have extended the non-adiabatic computations presented in Miglio et al. (2007) towards models of higher mass and pulsation modes of degree l = 3, and we present here the instability domains in the HR- and log P-log Teff diagrams resulting from different choices of opacity tables, and for three different metallicities. [less ▲]

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See detailEffect of convective outer layers modeling on non-adiabatic seismic observables of delta Scuti stars
Montalban Iglesias, Josefa ULg; Dupret, Marc-Antoine ULg

in Astronomy and Astrophysics (2007), 470

Context: The identification of pulsation modes in delta Scuti stars is mandatory for constraining the theoretical stellar models. The non-adiabatic observables used in the photometric identification ... [more ▼]

Context: The identification of pulsation modes in delta Scuti stars is mandatory for constraining the theoretical stellar models. The non-adiabatic observables used in the photometric identification methods depend, however, on convection modeling in the external layers. Aims: We determine how the treatment of convection in the atmospheric and sub-atmospheric layers affects the mode identification and what information about the thermal structure of the external layers can be obtained from amplitude ratios and phase lags in Strömgren photometric bands. Methods: We derive non-adiabatic parameters for delta Scuti stars by using, for the first time, stellar models with the same treatment of convection in the interior and in the atmosphere. We compute classical non-gray mixing length models, and as well non-gray ``full spectrum of turbulence'' (FST) models. Furthermore, we compute the photometric amplitudes and phases of pulsation by using the colors and the limb-darkening coefficients as derived from the same atmosphere models as used in the stellar modeling. Results: We show that the non-adiabatic phase-lag is mainly sensitive to the thermal gradients in the external layers, hence to the treatment of convection, and that this sensitivity is also clearly reflected in the multi-color photometric phase differences. [less ▲]

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See detailMultisite Observations of delta Scuti Stars 7 Aql and 8 Aql (a New delta Scuti Variable): The Twelfth STEPHI Campaign in 2003
Fox Machado, L.; Michel, Eric; Pérez Hernández, F. et al

in Astronomical Journal (The) (2007), 134

We present an analysis of the pulsation behavior of the delta Scuti stars 7 Aql (HD 174532) and 8 Aql (HD 174589), a new variable star, observed in the framework of the STEPHI XII campaign during 2003 ... [more ▼]

We present an analysis of the pulsation behavior of the delta Scuti stars 7 Aql (HD 174532) and 8 Aql (HD 174589), a new variable star, observed in the framework of the STEPHI XII campaign during 2003 June and July; 183 hr of high-precision photometry were acquired by using four-channel photometers at three sites on three continents during 21 days. The light curves and amplitude spectra were obtained following a classical scheme of multichannel photometry. Observations in different filters were also obtained and analyzed. Six and three frequencies have been unambiguously detected above a 99% confidence level in the range 190-300 muHz and 100-145 muHz in 7 Aql and 8 Aql, respectively. A comparison of observed and theoretical frequencies shows that 7 Aql and 8 Aql may oscillate with p-modes of low radial orders, typical among delta Scuti stars. In terms of radial oscillations the range of 8 Aql goes from n=1 to 3, while for 7 Aql the range spans from n=4 to 7. Nonradial oscillations have to be present in both stars as well. The expected range of excited modes according to a nonadiabatic analysis goes from n=1 to 6 in both stars. [less ▲]

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See detailDelayed information flow effect in economy systems. An ACP model study
Miskiewicz, J.; Ausloos, Marcel ULg

in Physica A-Statistical Mechanics and its Applications (2007), 382(1), 179-186

Applying any strategy requires some knowledge about the past state of the system. Unfortunately in the case of economy. collecting information is a (difficult, expensive and time consuming process ... [more ▼]

Applying any strategy requires some knowledge about the past state of the system. Unfortunately in the case of economy. collecting information is a (difficult, expensive and time consuming process. Therefore, the information about the system is usually known only at the end of some well-defined intervals, e.g. through company, national bank inflation data and Gross Domestic Product (GDP) reports, etc. They describe a (market) situation in the past. The time delay is specific to the market branch. It can be very short (e.g. stock market offer is updated every minute or so and this information is quasi-immediately available) or long, like months in the case of agricultural markets, when the decisions are taken based on the results from the previous harvest. The analysis of the information flow delay can be based oil the Ausloos-Clippe-Pekalski (ACP) model of spatial evolution of economic systems. The entities can move on a (square) lattice and when meeting take one of the two following decisions: merge or create a new entity. The decision is based on the system state, which is known with some time delay. The effect of system's feedback is hereby investigated. We consider the case of company distribution evolution in a heterogeneous field. The information flow time delay implies different final states, including cycles; it is like a control parameter in a logistic map. (C) 2007 Elsevier BN. All rights reserved. [less ▲]

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