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See detailThe oxygen nightglow emissions of Venus: vertical distribution and role of collisional quenching
Gérard, Jean-Claude ULg; Soret, Lauriane ULg; Migliorini, Alessandra et al

Conference (2012, April)

The oxygen nightglow emissions of Venus: vertical distribution and role of collisional quenching J.-C. Gérard (1), L. Soret (1), A. Migliorini (2), G. Piccioni (2), and P. Drossart (3) (1) LPAP ... [more ▼]

The oxygen nightglow emissions of Venus: vertical distribution and role of collisional quenching J.-C. Gérard (1), L. Soret (1), A. Migliorini (2), G. Piccioni (2), and P. Drossart (3) (1) LPAP - Université de Liège - Belgium (jc.gerard@ulg.ac.be, 0032 4 366 9711), (2) INAF - Rome, Italy, (3) LESIA, Observatoire de Paris - Meudon, France Three-body recombination of atomic oxygen produces O2 molecules excited in different electronic states such as a 1∆g, b 1 􏰀+g , A 3 􏰀+u , c 1 􏰀uand A’ 3∆u, each with a specific quantum efficiency. When they radiate, optical transitions are observed in a wide range of wavelengths extending from the ultraviolet to the near infrared. In planetary atmospheres, spontaneous radiative deexcitation compete with collisional quenching with ambient molecules and atoms. As a consequence, the corresponding airglow emission profiles may significantly differ from each other in brightness and altitude of the emitting layer. We model the volume emission rates and limb profiles of the O2 Atmospheric Infrared (a 1∆-X 3 􏰀), Herzberg I (A 3 􏰀-X 3 􏰀), Herzberg II (c 1 􏰀-X 3 􏰀), Chamberlain (A’ 3∆-a 1∆) bands expected on the Venus night side. The quenching rates are taken from laboratory and observational planetary data and we apply two different methods to determine the oxygen and CO2 density profiles. One is based on recent analysis of data collected by instruments on board the Venus Express mission. The second one uses a one-dimensional chemical-diffusive model where the free parameters are the strength of turbulent transport and the downward flux of O atoms. Both approaches indicate that the calculated intensities of each transition range over several orders of magnitude and that differences are expected in the altitude of the maximum emission. These predictions will be compared with VIRTIS/Venus Express limb observations, which make it possible to derive the vertical distribution of the O2 emissions in the visible and infrared. These measurements suggest that no difference is observed between the altitude of the peak of the IR Atmospheric and Herzberg II bands. Conclusions will be drawn about the validity of the current set of quenching coefficients used in the model. [less ▲]

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See detailDamping identification of lightly damped linear dynamic systems using Common-base Proper Orthogonal Decomposition
Andrianne, Thomas ULg; Dimitriadis, Grigorios ULg

in Mechanical Systems & Signal Processing (2012), 28

This paper presents a new technique to identify the damping of linear systems. It is developed from the Proper Orthogonal Decomposition (POD) of the free response of the system and extended to the ... [more ▼]

This paper presents a new technique to identify the damping of linear systems. It is developed from the Proper Orthogonal Decomposition (POD) of the free response of the system and extended to the recently proposed Common-base POD (CPOD). The present application of CPOD considers simultaneously several free responses of the system to different initial conditions. The eigen-decomposition of the co-variance matrix leads to a unique vector basis which is likely to contain more information about the dynamics of the system than a vector basis obtained by the classic POD technique. The ability of the technique to estimate the mode shapes and the modal damping is demonstrated on a simulated mass-spring-damper system. Two different distributions of masses are considered in order to confront the CPOD analysis to the intrinsic limitation of POD, i.e. that the mode shapes are identified exactly only if the mass matrix is proportional to the identity matrix. It is shown that the identification of the damping is still possible when the modes are not orthonormal. The robustness of the technique is demonstrated in the presence of noise in the responses of the system and through an experimental application with comparison with other identifications techniques. [less ▲]

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See detailCalcium-induced conformational changes of the elicitor and membrane-active fengycin
Nasir, Mehmet Nail ULg; Lins, Laurence ULg; Ongena, Marc ULg et al

Poster (2012, April)

Fengycin is a natural lipopeptide synthetized by Bacillus subtilis strains. It is characterized by strong antifungal and low hemolytic activities. It seems also play a role in the promoting of elicitor ... [more ▼]

Fengycin is a natural lipopeptide synthetized by Bacillus subtilis strains. It is characterized by strong antifungal and low hemolytic activities. It seems also play a role in the promoting of elicitor activities of other compounds. The target of the biological activities of fengycin is supposed to be plasma membrane of sensitive cells. Even though the natural fengycin from has been discovered 25 years ago, nowadays, there is an increase of interest for this compound because of its potent applications. Until 15 years ago, the primary structure of fengycin was a matter of open debate before the publication of the corrected structure obtained by nuclear magnetic resonance and mass spectroscopy techniques. Although the infrared and ultraviolet absorption spectra of the lipopeptide were measured, no detailed analysis of these data was performed probably because of the unconventional sequence of the lipopeptide making these kinds of analyses complicated. In this work, our attempt was to analyze the conformational properties of fengycin as well as the calcium-induced changes using two complementary spectroscopic methods, Fourrier transformed infrared spectroscopy (FTIR) and circular dichroism (CD). In a first step, we have characterized the conformational properties of pure fengycin. The lipopeptide adopts turn conformation in trifluoroethanol, a membrane-mimicking solvent. D-aminoacids seem to be involved in intra molecular hydrogen bonds. In a second step, we have investigated the role played by Ca2+ ions on the possible conformational changes of fengycin. The addition of calcium gives rise to important modifications of the conformation. As fengycin has two glutamate residues, calcium is supposed to bind to their side chains. In conclusion, we have demonstrated that the conformation of fengycin is closely depending of the environment and the presence of calcium ions play an important role on the conformational changes of the lipopeptide. Moreover, spectra obtained both FTIR and CD methods ascertain the presence of turn conformation. [less ▲]

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See detailHigher-Moment Risk Exposures in Hedge Funds
Lambert, Marie ULg; Hübner, Georges ULg; Papageorgiou, Nicolas

Conference (2012, April)

The paper singles out the key roles of US equity skewness and kurtosis in the determination of the market premia embedded in Hedge Fund returns. We propose a conditional higher-moment asset pricing model ... [more ▼]

The paper singles out the key roles of US equity skewness and kurtosis in the determination of the market premia embedded in Hedge Fund returns. We propose a conditional higher-moment asset pricing model with location, trading and higher-moment factors in order to describe the dynamics of the Equity Hedge (Market Neutral, Short Selling and Long/Short strategies), Event Driven, Relative Value, and Funds of Hedge Funds styles. The volatility, skewness and kurtosis implied in the US options markets are used by Hedge Fund managers as instruments to anticipate market movements. Managers should adjust their market exposure in response to variations in the implied higher moments. We show that higher-moment premia improve a conditional asset pricing model both in terms of explanatory power (R-squares and Schwarz criterion) and specification errors across all Hedge Fund styles. [less ▲]

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See detailBiological variations during a race cycling
LE GOFF, Caroline ULg; Kaux, Jean-François ULg; Goffaux, Sébastien et al

in Biomedica 2012 (2012, April)

Background: The metabolic and cardiac impact of a cycling effort on blood biology is not very well described in the literature. We aimed to measure the concentration of different biomarkers (cardiac and ... [more ▼]

Background: The metabolic and cardiac impact of a cycling effort on blood biology is not very well described in the literature. We aimed to measure the concentration of different biomarkers (cardiac and metabolic) released during an international cycling race. Materials and Methods: Venous blood samples of 15 young men (25.1 ± 6.4 y.o.) were collected just before (T1), just after (T2), 3 hours (T3) after an international cycling race of 176 kilometers in Belgium for the determination of cardiac and metabolic biomarkers: red blood cells (RBC) haemoglobin (HgB) creatinin (Cr) highly sensitive troponin T (hsTnT) myoglobin (MYO) NT-proBNP All automated assays were performed according to the manufacter’s specifications. For the statistical analysis, an Anova calculated with the Statistica Software version 9.1 was used. Results: •RBC and HgB levels varied significantly between T0 and T3 (respectively p=0.0026, and p=0.002) (Fig. 1 and 2). • Cr concentration also varied significantly between all times (T0-T1:p<0.0001, T1-T3:p=0.0326 and T0-T3 p=0.0001)(Fig.3). These changes might be related to renal flow depletion during exercise. •MYO increased significantly between T0 and T1 (p<0.0001), but quickly decreased between T1 and T3, however the T3 level stay higher than T0 (p=0.014) (Fig.4). •The stress delivered from the physical activity performed during the race induced a significant variation of hsTnT which increased significantly between T0 and T1 (p<0.0001) and stayed higher 3 hours after the end of the exercise (T0-T3: p<0.0001) (Fig.5) . •The intense exercise delivery by the race induced a significant variation of NT-proBNP, that followed the same kinetic of hsTnT but in smaller proportion. We noticed variations statistically significant between T0 and T1 and between T0 and T3 for NT-proBNP (Fig.6). •These increases of cardiac biomarkers were significant but reasonable and could not allow us to talk about cellular necrosis or irreversible injury. Conclusions: Our results show that stress generated by a cycling race could be the cause for the different metabolic variations observed. Troponin T stays without a doubt the most specific marker for stress related to myocardial tissue. Its increase can then be considered as being of interest. [less ▲]

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See detailDroits de succession et de mutation par décès
Bourgeois, Marc ULg; Douny, Raphaël ULg; Gustin, Manuel ULg et al

in Chroniques notariales (2012)

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See detailL'ancien institut de stomatologie à Bavière en sursis
Charlier, Sébastien ULg

in Nouvelles du Patrimoine (Les) (2012), 135

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See detailEditorial
Bullens, Quentin ULg

in Carnet de Notes sur les Maltraitances Infantiles (2012), 1

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See detailPrediction of the cross-section capacity of hot-rolled profiles using the direct strength method and the continuous strength method
Li, Yongzhen ULg; Rossi, Barbara ULg

in Chan, S.L.; Shu, G.P. (Eds.) Proceedings of seventh International Conference on Advances in Steel Structures (2012, April)

Material yielding on one hand and local buckling on the other hand limit the cross-section capacity of steel structural members. Current structural design codes use the concept of cross-section ... [more ▼]

Material yielding on one hand and local buckling on the other hand limit the cross-section capacity of steel structural members. Current structural design codes use the concept of cross-section classification to determine the cross-section resistance of hot-rolled profiles. In this system, the Effective Width Method (EWM) is employed to account for local buckling effects for slender, class 4, cross-sections. Alternative design methods for treatment of local buckling in metallic cross-sections have been proposed, including the Direct Strength Method (DSM), developed for cold-formed steel structural profiles, and, recently, the Continuous Strength Method (CSM). The DSM is based on the assumption that the strength can be predicted from the ratio of the yield strength to the elastic critical load in conjunction with a strength curve for the entire cross-section. Thus it is essentially an extension of the use of column curves for global buckling, but with application to local buckling instability. The CSM is a deformation-based design approach which is based on a continuous relationship between cross-sectional slenderness and cross-section deformation capacity and a rational exploitation of strain hardening. This paper is focused on the evaluation of the cross-sectional resistance of hot-rolled structural profiles. Test data from literature experimental programmes have been gathered and analysed to compare the predictions from the DSM and CSM design approaches. [less ▲]

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See detailPlatelet-rich plasma to treat jumper’s knee: preliminary results
Kaux, Jean-François ULg; CROISIER, Jean-Louis ULg; SIMONI, Paolo ULg et al

in Biomedica 2012 (2012, April)

Introduction: Tendinopathies, especially jumper’s knee, often remain rebel to conservative treatments. Several experimental studies have shown the healing properties of platelet and their growth factors ... [more ▼]

Introduction: Tendinopathies, especially jumper’s knee, often remain rebel to conservative treatments. Several experimental studies have shown the healing properties of platelet and their growth factors. Researches have specifically demonstrated the platelets action as mediator and/or enhancer of tissue healing. The aim of our study was to investigate the effect of 1 injection of PRP in patients suffering from chronic jumper’s knee. Our protocol was approved by Ethic Committee of University and University Hospital of Liège. Methods: Patients performed imaging (US and MRI) and functional assessments, and a clinical examination using an algometer, before treatment and 6 weeks after PRP treatment. They were also invited to answer to questionnaire relative to pain and functional status. PRP was obtained from autologous blood using an apheresis system (COM.TEC, Fresenius). The injection of 6mL of PRP was realised without local anaesthesia into the proximal insertion of the patellar tendon. A 48h rest-time was recommended after infiltration. Afterwards, a submaximal eccentric reeducation was initiated 1 week after infiltration 3 times a week during 5 weeks. In case of pain, anti-inflammatory drugs were prohibited and patient were encouraged to take class I or II painbrakers. Results: At this time, 10 patients with jumper’s knee were included in our study. Pre-injection tests revealed pain of the upper part of the patellar tendon just below the patella, associated with loss of function. Imaging exams confirmed diagnosis. Six weeks post-injection, the clinical status was improved in all patients, with a significant decrease of algo-functional scores. The pain reported during functional assessments was decreased (in particular for the eccentric actions), yet no significant improvement of physical performances was observed. We found no significant differences between imaging exams before and 6 weeks after PRP injection. Conclusion: One in situ injection of PRP clinically improved patients with jumper’s knee 6 weeks after treatment. All the 10 patients reported a decrease of pain during day-life and through physical activities. However nor functional performances neither imaging were improved. [less ▲]

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See detailhe influence of transformational leadership on commitment: New underlying processes
Marique, Géraldine; Stinglhamber, Florence; Hanin, Dorothée et al

Poster (2012, April)

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See detailVulgariser et distinguer. Stratégies médiatiques autour du discours théorique
Provenzano, François ULg

in Discours et la Langue (Le) (2012), 2(2), 199-209

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See detailL'invité du mois : Jean-François Husson, secrétaire général du CRAIG (Centre de Recherche en Action publique, Intégration et Gouvernance)
Depret, Alain; Husson, Jean-François ULg

Article for general public (2012)

Interview accordée au périodique de l'Union des Villes et Communes de Wallonie sur les activités du CRAIG et sur plusieurs de mes sujets de recherche : finances locales, gouvernance locale, financement ... [more ▼]

Interview accordée au périodique de l'Union des Villes et Communes de Wallonie sur les activités du CRAIG et sur plusieurs de mes sujets de recherche : finances locales, gouvernance locale, financement des cultes. [less ▲]

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See detailIntroduction générale
Bouhon, Frédéric ULg; Reuchamps, Min ULg

in Bouhon, Frédéric; Reuchamps, Min (Eds.) Les systèmes électoraux de la Belgique (2012)

Cette introduction ouvre un ouvrage collectif consacré aux systèmes électoraux de la Belgique. Elle insiste sur le caractère multidisciplinaire de l'étude des questions électorales qui est proposée dans ... [more ▼]

Cette introduction ouvre un ouvrage collectif consacré aux systèmes électoraux de la Belgique. Elle insiste sur le caractère multidisciplinaire de l'étude des questions électorales qui est proposée dans le livre et en présente le plan. [less ▲]

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See detailChargement de marchandises dans un avion cargo: le cas des marchandises nécessitant des précautions particulières
Schyns, Michael ULg; Limbourg, Sabine ULg; Kleyntssens, Thomas ULg

Conference (2012, April)

D'une part, les entreprises de transport aérien ont acheminé en 2010 plus d’un tiers de la valeur des exportations mondiales. D'autre part, le chargement des avions est une opération complexe soumise à de ... [more ▼]

D'une part, les entreprises de transport aérien ont acheminé en 2010 plus d’un tiers de la valeur des exportations mondiales. D'autre part, le chargement des avions est une opération complexe soumise à de nombreuses contraintes et peu d'outils sont disponibles pour aider les loadmasters à trouver la meilleure disposition des conteneurs dans les avions. Limbourg, Schyns et Laporte (2011) ont proposé un modèle à variables entières pour traiter les problèmes élémentaires. Notre travail est une extension de ces travaux. Nous considérons des chargements spéciaux qui impliquent des précautions particulières (produits dangereux, animaux, produits réfrigérés, aliments périssables, ...) ainsi que le transport de marchandises de plus grande taille. L’ajout de ces deux types de contraintes se justifie par la grande fréquence de ces situations dans des problèmes réels rencontrés par nos partenaires industriels. Le problème résultant est très complexe et nous proposons un outil pour le résoudre. [less ▲]

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See detailEcouter le bruit, faire entendre la gêne
Colon, Paul-Louis ULg

in Communications (2012), (90), 95-107

Noise issues and ordinary listening have long been adressed separately in the social sciences. This paper argues in favor of the usefulness of an integrated approach to both, from the standpoint of an ... [more ▼]

Noise issues and ordinary listening have long been adressed separately in the social sciences. This paper argues in favor of the usefulness of an integrated approach to both, from the standpoint of an ethnographic investigation on the perception and management of sonic environment which was carried out in French-speaking Belgium. This heuristic approach – combining listening and noise – makes it possible to describe the process of when the feeling of annoyance comes about and the ability for annoyed people to express it. [less ▲]

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See detailUse of ionic liquids for biocatalytic synthesis of sugar derivatives
Galonde, Nadine ULg; Nott, Katherine ULg; Debuigne, Antoine ULg et al

in Journal of Chemical Technology & Biotechnology (2012), 87(4), 451-471

Sugar-based compounds are widely used in pharmaceuticals, cosmetics, detergents and food. They are mainly produced by chemical methods, but the use of enzymes as ‘a greener alternative’ to organic ... [more ▼]

Sugar-based compounds are widely used in pharmaceuticals, cosmetics, detergents and food. They are mainly produced by chemical methods, but the use of enzymes as ‘a greener alternative’ to organic synthesis has been investigated for more than 20 years. Due to the low polar substrate solubility in organic solvents compatible with enzymes, research has focused on the application of substitutes for biocatalysis, especially ionic liquids (ILs). After introducing the main properties of ILs and especially their ability to solubilize sugars, this review focuses on one of their applications, the biocatalytic synthesis of carbohydrate derivatives. In this context, they can be used in pure IL systems, in IL/IL systems or in IL/organic solvent systems. Finally, this review provides an update on the environmental fate of ILs. Their exploitation in ‘green’ processes is still limited due to their low degradability but research is currently under way to design new more ‘eco-friendly’ ILs. [less ▲]

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