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See detailContribution à la mission CoRoT et à la recherche d'exoplanètes par la méthode des transits photométriques
Gillon, Michaël ULg

Doctoral thesis (2006)

In this thesis, we present our contributions to the CoRoT mission and to the search for exoplanets with the photometric transit method. We developped a spectroscopic analysis method, APASS, which allows ... [more ▼]

In this thesis, we present our contributions to the CoRoT mission and to the search for exoplanets with the photometric transit method. We developped a spectroscopic analysis method, APASS, which allows to obtain a precise determination of atmospheric physical parameters and abundances for stars with an unnegligeable rotational speed. We present APASS and the high-precision results we obtained for main target stars of the asteroseismological part of the CoRoT mission. Our results are in agreement with those obtained by other authors using different analysis methods, while beeing more precise. Furthermore, they show that the use of a spectroscopic analysis method based on equivalent widths measurements by gaussian or Voigt profiles fitting should be avoided for stars whose rotational velocity is significantly higher then the Sun’s, and that a method using synthetic spectra fitting for which the convolution is a free parameter should be prefered. Next, we investigate the potential of extrasolar planet transit surveys. We show that CoRoT has a very high potential for the detection of close-in giant planets, better than the one of the KEPLER mission. This latter reveals to be better for the detection of terrestrial planets. Nevertheless, CoRoT could detect a few giant telluric planets of short orbital period, provided that this kind of object is frequent in our galaxy. For ground-based surveys, our results based on the use of large telescopes and wide-field cameras seem to indicate that an important potential is also available from the ground. These results are nevertheless less reliable, mainly because of the lack of knowledge about the influence of systematic effects, and additional investigations using actual data will be necessary. We present then the deconvolution method MCS and the way we adapted it to planetary transit photometry. We present the results we obtained after analysis of actual data for OGLE-TR-123 (VLT/FORS2 data) and OGLE-TR-132 (VLT/FORS2 and NTT/SUSI2 data). These results are very encouraging and demonstrate the high potential of MCS for this kind of high-precision analysis. Finally, we present the future improvements we intend to install to obtain a still higher level of precision and to increase the speed of analysis. [less ▲]

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See detailPour une théorie du corps reltionnel
Gauthier, Jean-Marie ULg

in Psychosomatique : y croire ou pas (2006), XXXVII 1/06(Septembre 2006), 105-114

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See detailUltimate limit state design technology for aluminum multi-hull ship structures
PAIK, Jeom; HUghes, Owen; Rigo, Philippe ULg

in Transactions - Society of Naval Architects and Marine Engineers (2006), 113

The present paper is a summary of recent research and developments related to some core ultimate limit state (ULS) technologies for design and strength assessment of aluminum multi-hull ship structures ... [more ▼]

The present paper is a summary of recent research and developments related to some core ultimate limit state (ULS) technologies for design and strength assessment of aluminum multi-hull ship structures, jointly undertaken by Pusan National University, Virginia Tech, U.S. Naval Surface Warfare Center and Alcan Marine. An extensive study on the subject has been undertaken by the authors theoretically, numerically and experimentally. Methods to analyze hull girder loads I load effects, stiffened panel ultimate strength and hull girder ultimate strength of aluminum multi-hull ship structures are developed in the present study. Application examples of the methodologies for the ULS structural design and strength assessment of a hypothetical 120m long all aluminum catamaran fast ship structure are presented. Important insights and conclusions developed from the present study are summarized. Some of the comparisons have shown that 5383 called Sealium (a patented Alcan Marine alloy) is superior to the standard aluminum alloy 5083 in terms of material properties, ULS characteristics and welding performance. It is our hope that the methods developed from the present study will be useful for ULS design and strength assessment of aluminum multi-hull ship structures. [less ▲]

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See detailSerum plant sterols and atherosclerosis: is there a place for statin-ezetimibe combination?
Radermecker, Régis ULg; Scheen, André ULg

in Journal of the American College of Cardiology (2006), 47(7), 1496-71497-8

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See detailCombined spastic paresis of both gastrocnemius and femoral quadriceps muscles in Belgian blue calves
Janda, Jozef; Uyttenhoef, Aude; Vandeputte, Sébastien ULg et al

Conference (2006)

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See detailMinireview: the neuroendocrine regulation of puberty: is the time ripe for a system biology approach?
Ojeda, Sergio; Lomniczi, Alejandro; Mastronardi, Claudio et al

in Endocrinology (2006), 147

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See detailNeuroendocrine mechanisms controlling female puberty: new approaches, new concepts.
Ojeda, S.; Roth, C.; Mungenast, A. et al

in International Journal of Andrology (2006), 29

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See detailPhotography as diagnosis of contemporaneity
Dondero, Maria Giulia ULg

in Baetens, Jan; Van Gelder, Hilde (Eds.) Critical Realism in Contemporary Art. Around Allan Sekula’s Photography (2006)

Cet article porte sur l’efficacité politique d’une série photographique qui problématise des questions socioculturelles contemporaines telles l’immigration, l’exploitation et l’éthique du travail. L’image ... [more ▼]

Cet article porte sur l’efficacité politique d’une série photographique qui problématise des questions socioculturelles contemporaines telles l’immigration, l’exploitation et l’éthique du travail. L’image photographique devient une ressource dans les mains des acteurs sociaux et fait fonction de diagnostic des tensions du contemporain. La photographie permet de «reconnaître à travers» (c’est-à-dire « diagnostiquer ») et de formuler des jugements. Le potentiel sémantique du diagnostic engendré par cette série et la force illocutoire des jugements qui y sont inscrits fonctionnent comme une sorte d’« argumentation par images ». L’analyse de cette série photographique, réalisée par le photographe et théoricien Allan Sekula, nous a amené à nous interroger sur la relation entre image, corpus, genres d’afférence et statuts (documentaire et artistique). [less ▲]

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See detail“Questions particulières du droit de l'exécution des sentences et plus généralement des décisions des arbitres”
Wautelet, Patrick ULg

in Keutgen, Guy (Ed.) La sentence arbitrale (2006)

This paper addresses specific quesitons in relation to the arbitral award. A first question dealt with, concerned the consequences and effects an arbitral award may have before a state court grants it ... [more ▼]

This paper addresses specific quesitons in relation to the arbitral award. A first question dealt with, concerned the consequences and effects an arbitral award may have before a state court grants it exequatur. Two sub-questions are discussed : whether such award may have res judicata, and, if yes, what consequences may follow from the res judicata and second whether provisional measures may be ordered on the basis of the award before the exequatur is granted. In a second chapter, attention is devoted to the seminal question of the possibility to enforce an award which has been annulled. This is done by exploring the effects of a request for annulment on the effects of an award and then discussing the consequences the annulment proper may have on the award. Finally, the position of the award debtor is also discussed in relation to enforcement proceedings. In particular, the possibility for the debtor to file a negative declaratory action and to request to be joined in enforcement proceedings are discussed. [less ▲]

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See detailReactivity of penicillin-binding proteins with peptidoglycan-mimetic beta-lactams: what's wrong with these enzymes?
Josephine, Helen R.; Charlier, Paulette ULg; Davies, Christopher et al

in Biochemistry (2006), 45(51), 15873-83

Beta-lactams exert their antibiotic action through their inhibition of bacterial DD-peptidases (penicillin-binding proteins). Bacteria, in general, carry several such enzymes localized on the outside of ... [more ▼]

Beta-lactams exert their antibiotic action through their inhibition of bacterial DD-peptidases (penicillin-binding proteins). Bacteria, in general, carry several such enzymes localized on the outside of their cell membrane to catalyze the final step in cell wall (peptidoglycan) synthesis. They have been classified into two major groups, one of high molecular weight, the other of low. Members of the former group act as transpeptidases in vivo, and their inhibition by beta-lactams leads to cessation of bacterial growth. The latter group consists of DD-carboxypeptidases, and their inhibition by beta-lactams is generally not fatal to bacteria. We have previously shown that representatives of the former group are ineffective at catalyzing the hydrolysis/aminolysis of peptidoglycan-mimetic peptides in vitro [Anderson et al. (2003) Biochem. J. 373, 949-955]. The theme of these experiments is expanded in the present paper where we describe the synthesis of a series of beta-lactams (penicillins and cephalosporins) containing peptidoglycan-mimetic side chains and the kinetics of their inhibition of a panel of penicillin-binding proteins spanning the major classes (Escherichia coli PBP 2 and PBP 5, Streptococcus pneumoniae PBP 1b, PBP 2x and PBP 3, the Actinomadura R39 DD-peptidase, and the Streptomyces R61 DD-peptidase). The results of these experiments mirror and expand the previous results with peptides. Neither peptides nor beta-lactams with appropriate peptidoglycan-mimetic side chains react with the solubilized constructs of membrane-bound penicillin binding proteins (the first five enzymes above) at rates exceeding those of generic analogues. Such peptides and beta-lactams do react at greatly enhanced rates with certain soluble low molecular weight enzymes (R61 and R39 DD-peptidases). The former result is unexpected and interesting. Why do the majority of penicillin-binding proteins not recognize elements of local peptidoglycan structure? Possible answers are discussed. That this question needs to be asked casts fascinating shadows on current studies of penicillin-binding proteins for new drug design. [less ▲]

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See detailCharacterisation of bio-insecticide proteins in industrial residues from pea seeds (Pisum sativum L.)
Cuertero Diaz, Gaetan; Colinet, Frederic; Portetelle, Daniel ULg et al

in Abstract book (2006)

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See detailEffects of long-term population fluctuations in a top predator on invertebrate community composition in Alpine ponds
Wissinger, Scott; Whiteman, Howard; Denoël, Mathieu ULg

Conference (2006)

At our remote study site in central Colorado, the population size of tiger salamanders (Ambystoma tigrinum nebulosum) has fluctuated cyclically over the past 20 years from fewer than 100 to over 5000 ... [more ▼]

At our remote study site in central Colorado, the population size of tiger salamanders (Ambystoma tigrinum nebulosum) has fluctuated cyclically over the past 20 years from fewer than 100 to over 5000 individuals. Comparative data between ponds with and without salamanders, and experimental studies suggest that this species is a keystone predator on benthic and planktonic prey communities. Here we present long-term community data that reveal taxon- and habitat-specific correlations in the population size of benthic and planktonic prey with fluctuations in salamander populations. Changes in the abundance of planktonic, but not benthic invertebrates in temporary habitats were correlated with fluctuations in the abundance of salamanders. In permanent ponds, we observed order-of-magnitude changes in benthic biomass that are negatively correlated with salamander abundance. Among the large-bodied and potentially most vulnerable benthic invertebrates (odonates, caddisflies, beetles, water bugs), several species exhibited negatively coupled cycles, but others fluctuated little or out of phase with changes in salamander abundance. The absence of major shifts in benthic community composition in permanent ponds is probably a result of conflicting predation pressures exerted by different year classes of salamanders. Salamander gut samples suggest that ontogenetic shifts in diet might explain why cyclic fluctuations in the abundance of this predator had only minor impacts on benthic community composition despite having major effects on invertebrate biomass. [less ▲]

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See detailStudy of precursors responsible for off-flavor formation during storage of potato flakes.
Laine, G.; Göbel, Cornelia; du Jardin, Patrick ULg et al

in Journal of Agricultural and Food Chemistry (2006), 54

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See detailMechanisms of cohort suppression and population fluctuation in tiger salamanders
Whiteman, Howard; Wissinger, Scott; Denoël, Mathieu ULg

Conference (2006)

The mechanisms underlying population fluctuation have been well studied in mammals and insects but less research has focused on amphibians. Yet, the current global decline of amphibians equires that we ... [more ▼]

The mechanisms underlying population fluctuation have been well studied in mammals and insects but less research has focused on amphibians. Yet, the current global decline of amphibians equires that we understand these mechanisms, and be able to distinguish between anthropogenically induced declines and natural population fluctuations. We have followed a marked population of the Arizona tiger salamander, Ambystoma tigrinum nebulosum, for over 16 years during which time the population has completed two “boom and bust” cycles, generated by a dominant cohort that appears to suppress larval recruitment until it senesces. We tested two hypotheses for this suppression, cannibalism and resource depression, using a series of meso- and microcosm experiments. We found significant lethal and sublethal (behavior, diet, growth rates) effects of cannibalism by large larvae and paedomorphic adults on hatchling and 1st-year larvae, suggesting that both cannibalism and the threat of cannibalism are important in cohort suppression. Resource depression experiments revealed that paedomorphic adults did not affect larval survival, diet, or growth, despite reduced prey densities, because paedomorphs mainly reduced large bodied prey, whereas hatchlings fed primarily on smaller benthic and zooplanktonic invertebrates. Future experiments will determine how hatchlings are impacted by boom cohorts that are more similar in size and diet. Our results lend insight into the mechanisms underlying fluctuations in this population, and suggest that a better understanding of natural population fluctuations will aid amphibian conservation efforts. [less ▲]

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