Publications ORBi OA
Bookmark and Share    
Full Text
Peer Reviewed
See detailRise of oceanographic barriers in continuous populations of a cetacean: the genetic structure of harbour porpoises in Old World waters
Fontaine, Michaël C. ULg; Baird, Stuart J. E.; Piry, Sylvain et al

in BMC Biology (2007), 5

BACKGROUND: Understanding the role of seascape in shaping genetic and demographic population structure is highly challenging for marine pelagic species such as cetaceans for which there is generally ... [more ▼]

BACKGROUND: Understanding the role of seascape in shaping genetic and demographic population structure is highly challenging for marine pelagic species such as cetaceans for which there is generally little evidence of what could effectively restrict their dispersal. In the present work, we applied a combination of recent individual-based landscape genetic approaches to investigate the population genetic structure of a highly mobile extensive range cetacean, the harbour porpoise in the eastern North Atlantic, with regards to oceanographic characteristics that could constrain its dispersal. RESULTS: Analyses of 10 microsatellite loci for 752 individuals revealed that most of the sampled range in the eastern North Atlantic behaves as a 'continuous' population that widely extends over thousands of kilometres with significant isolation by distance (IBD). However, strong barriers to gene flow were detected in the south-eastern part of the range. These barriers coincided with profound changes in environmental characteristics and isolated, on a relatively small scale, porpoises from Iberian waters and on a larger scale porpoises from the Black Sea. CONCLUSION: The presence of these barriers to gene flow that coincide with profound changes in oceanographic features, together with the spatial variation in IBD strength, provide for the first time strong evidence that physical processes have a major impact on the demographic and genetic structure of a cetacean. This genetic pattern further suggests habitat-related fragmentation of the porpoise range that is likely to intensify with predicted surface ocean warming. [less ▲]

Detailed reference viewed: 29 (7 ULg)
Full Text
Peer Reviewed
See detailExperimental investigations on the behaviour of a composite frame after the loss of a column
Demonceau, Jean-François ULg; Jaspart, Jean-Pierre ULg

in Beale, R. G. (Ed.) Proceeding of the 6th International Conference on Steel and Aluminium Structures (2007, July 24)

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional loading, i.e. other accidental loads than ... [more ▼]

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional loading, i.e. other accidental loads than those already taken into consideration in the design process. According to Eurocodes and some other national design codes, the structural integrity of civil engineering structures should be ensured through appropriate measures but, in most of the cases, no precise practical guidelines on how to achieve this goal are provided. Even basic requirements to fulfil are generally not clearly expressed. An European RFCS project called “Robust structures by joint ductility” has been set up in 2004, for three years, with the aim to provide requirements and practical guidelines allowing to ensure the structural integrity of steel and composite structures under exceptional loading through an appropriate robustness. This project involves analytical, numerical and experimental investigations; in particular, one substructure test simulating the loss of a column in a composite building, because of an unexpected impact, was performed in September 2006 at the University of Liège. This paper describes the experimental test carried out at the University of Liège, as part of this European project, and the first interpretation of the results. [less ▲]

Detailed reference viewed: 52 (10 ULg)
Full Text
Peer Reviewed
See detailPromoter-dependent effect of IKK alpha on NF-kappa B/p65 DNA binding
Gloire, Geoffrey ULg; Horion, Julie; El Mjiyad, Nadia ULg et al

in Journal of Biological Chemistry (2007), 282(29), 21308-21318

IKK alpha regulates many chromatin events in the nuclear phase of the NF-kappa B program, including phosphorylation of histone H3 and removal of co-repressors from NF-kappa B-dependent promoters. However ... [more ▼]

IKK alpha regulates many chromatin events in the nuclear phase of the NF-kappa B program, including phosphorylation of histone H3 and removal of co-repressors from NF-kappa B-dependent promoters. However, all of the nuclear functions of IKK alpha are not understood. In this study, using mouse embryonic fibroblasts IKK alpha knock-out and reexpressing IKK alpha after retroviral transduction, we demonstrate that IKK alpha contributes to NF-kappa B/p65 DNA binding activity on an exogenous kappa B element and on some, but not all, endogenous NF-kappa B-target promoters. Indeed, p65 chromatin immunoprecipitation assays revealed that IKK alpha is crucial for p65 binding on kappa B sites of icam-1 and mcp-1 promoters but not on i kappa b alpha promoter. The mutation of IKK alpha putative nuclear localization sequence, which prevents its nuclear translocation, or of crucial serines in the IKK alpha activation loop completely inhibits p65 binding on icam-1 and mcp-1 promoters and rather enhances p65 binding on the i kappa b alpha promoter. Further molecular studies demonstrated that the removal of chromatin-bound HDAC3, a histone deacetylase inhibiting p65 DNA binding, is differentially regulated by IKK alpha in a promoter-specific manner. Indeed, whereas the absence of IKK alpha induces HDAC3 recruitment and repression on the icam-1 promoter, it has an opposite effect on the i kappa b alpha promoter, where a better p65 binding occurs. We conclude that nuclear IKK alpha is required for p65 DNA binding in a gene-specific manner. [less ▲]

Detailed reference viewed: 71 (9 ULg)
Full Text
See detailBulletin agrométéorologique - Situation fin juin 2007
Tychon, Bernard ULg; Schyns, Virginie; Denis, Antoine ULg et al

in Bulletin Agrométéorologique (2007), 6(1), 1-4

Detailed reference viewed: 16 (1 ULg)
Full Text
Peer Reviewed
See detailEffect of tibolone on breast cancer cell proliferation in postmenopausal ER+ patients: Results from STEM trial
Kubista, E.; Gomez, JVMP; Dowsett, M. et al

in Clinical Cancer Research : An Official Journal of the American Association for Cancer Research (2007), 13(14), 4185-4190

Purpose: Tibolone is a selective tissue estrogenic activity regulator, approved for the treatment of vasomotor symptoms in postmenopausal women. We have done an exploratory, double-blind, randomized ... [more ▼]

Purpose: Tibolone is a selective tissue estrogenic activity regulator, approved for the treatment of vasomotor symptoms in postmenopausal women. We have done an exploratory, double-blind, randomized, placebo-controlled pilot trial to investigate the tissue-specific effects of 2.5 mg tibolone on breast cancer in postmenopausal women, in particular on tissue proliferation (STEM, Study of Tibolone Effects on Mamma carcinoma tissue). Experimental Design: Postmenopausal women with initially stage I/II, estrogen receptor-positive (ER+) primary breast cancer, were randomly assigned to 14 days of placebo or 2.5 mg/d tibolone. Core biopsies of the primary tumor were obtained before and after treatment. Ki-67 and apoptosis index were analyzed in baseline and corresponding posttreatment specimen. Results: Of 102 enrolled patients, 95 had evaluable data. Baseline characteristics were comparable between both treatment groups. Breast cancer cases are mainly invasive (99%), stage I or II (42% and 50% respectively), and ER+ (99%). Median intratumoral Ki-67 expression at baseline was 13.0%, in the tibolone group and 17.8% in the placebo group, and decreased to 12.0% after 14 days of tibolone while increasing to 19.0% in the placebo group. This change from baseline was not significantly different between tibolone and placebo (Wilcoxon test; P = 0.17). A significant difference was observed between the treatment groups when the median change from baseline apoptosis index was compared between the treatment groups (tibolone, 0.0%; placebo, +0.3%; Wilcoxon test; P = 0.031). The incidence of adverse effects was comparable. Conclusions: In ER+ breast tumors, 2.5 mg/d tibolone given for 14 days has no significant effect on tumor cell proliferation. [less ▲]

Detailed reference viewed: 13 (0 ULg)
Full Text
Peer Reviewed
See detailGoogle Earth et Windows Live Search Maps: Analyse fonctionnelle et comparaison
Lonchay, Matthieu ULg

in Bulletin de la Société Géographique de Liège (2007), 49

« Google Earth » and « Windows Live Maps » are two services of web mapping recently developed by two competitive American corporations: « Google » and « Microsoft Corporation ». These services, whose ... [more ▼]

« Google Earth » and « Windows Live Maps » are two services of web mapping recently developed by two competitive American corporations: « Google » and « Microsoft Corporation ». These services, whose working requires specific computer technologies, provide a visualization of the Earth using an assemblage of satellite images and aerial photographs. This article is written to try to establish a functional analysis and a comparison of free versions of these two services of web mapping based on their technical characteristics, qualities of their sources, levels of provided functionalities and additional possibilities of paying versions. [less ▲]

Detailed reference viewed: 370 (30 ULg)
Full Text
See detailLateral-torsional Buckling of Ferritic Stainless Steel Beams in Case of Fire
Lopes, Nuno; Vila Real, Paulo; Da Silva, Luis et al

in Proceedings of the first International Conference on the Art of Resisting Extreme Natural Forces (2007, July 12)

This work presents a numerical study of the behaviour of ferritic stainless steel Ibeams subjected to lateral-torsional buckling and compares the obtained results with the beam design curves of Eurocode 3 ... [more ▼]

This work presents a numerical study of the behaviour of ferritic stainless steel Ibeams subjected to lateral-torsional buckling and compares the obtained results with the beam design curves of Eurocode 3. New formulae, for the lateraltorsional buckling, that approximate better the real behaviour of ferritic stainless steel structural elements in case of fire are proposed. These new formulae were based on numerical simulations using the program SAFIR, which was modified to take into account the material properties of the stainless steel. [less ▲]

Detailed reference viewed: 28 (1 ULg)
Full Text
See detailAvoir le véhicule vert
Bay, Maud ULg; Ozer, Pierre ULg; Perrin, Dominique ULg et al

Article for general public (2007)

L'argument est séduisant d'acquérir un nouveau véhicule, plus propre en émission de CO2, mais il faut aussi se débarrasser de son ancien. Attention au bilan CO2 total de l'opération ! [...] De plus en ... [more ▼]

L'argument est séduisant d'acquérir un nouveau véhicule, plus propre en émission de CO2, mais il faut aussi se débarrasser de son ancien. Attention au bilan CO2 total de l'opération ! [...] De plus en plus d'entreprises s'emparent des problématiques environnementales pour vanter leurs produits "plus écologiques". Il faut bien avouer que, suite au film d'Al Gore sur le réchauffement climatique et aux interventions très médiatisées de Nicolas Hulot sur l'urgence écologique, le sujet est très à la mode dans notre pays. D'autant plus qu'au cours des trois dernières années de divers constructeurs automobiles devenues très "vertes" nous incitent à remplacer notre ancien véhicule "polluant" par un nouveau, plus économe en carburant et donc plus propre également en émissions de CO2. Certes l'argument est séduisant. Il faut cependant prendre garde de ne pas oublier que la production, le transport, le marketing et le démantèlement d'un nouveau véhicule émettent aussi beaucoup de CO2 et doivent donc être pris en compte dans le "bilan CO2" total de l'opération. [...] [less ▲]

Detailed reference viewed: 96 (21 ULg)
Full Text
See detailNonvisual brain responses to light exposure in human as assessed by functional magnetic resonance imaging
Vandewalle, Gilles ULg

Doctoral thesis (2007)

La lumière influence profondément la physiologie humaine, en plus de permettre la vision. Elle constitue le synchronisateur principal des rythmes circadiens et induit des effets physiologiques immédiats ... [more ▼]

La lumière influence profondément la physiologie humaine, en plus de permettre la vision. Elle constitue le synchronisateur principal des rythmes circadiens et induit des effets physiologiques immédiats. Ces effets concernent des fonctions non-visuelles telles que la régulation du rythme veille/sommeil, de la température corporelle, de fonctions endocrinologiques, de l’éveil et des performances. Plusieurs études de ces effets réalisées chez l’animal et chez l’homme ont montré l’implication d’un système de photoréception non-visuel sensible surtout aux courtes longueurs d’onde (~470nm ; bleu). Ce système utilise les photorécepteurs classiques (cônes et bâtonnets), en plus de cellules ganglionnaires rétiniennes (CGR) intrinsèquement photosensibles, et exprimant la mélanopsine. Ces CGR se connectent à de nombreux noyaux sous-corticaux et corticaux, ce qui suggère un rôle du système non-visuel dans de nombreuses fonctions cérébrales. Cependant, au delà de ces projections rétiniennes directes, les autres régions du cerveau impliquées sont très peu connues. Une étude en tomographie par émission de positons (TEP), réalisée à l’Université de Liège, a démontré que l’effet éveillant d’une lumière nocturne intense (>8000lux) pouvait moduler l’activité cérébrale liée à une tâche attentionnelle. Cette étude, ainsi que quelques données d’EEG, résume notre connaissance des mécanismes cérébraux impliqués dans le système non-visuel chez l’homme. De plus, la majorité des études sur ces effets ont été entreprises la nuit. Nous avons réalisé trois études en imagerie fonctionnelle par résonance magnétique (IRMf) utilisant des expositions lumineuses diurnes pour mieux caractériser le système cérébral non-visuel chez l’homme. L’IRMf bénéficie d’une meilleure résolution spatiale et temporelle que la TEP et permet la caractérisation d’activités cérébrales liées à un processus cognitif précis. La première étude met en évidence des réponses cérébrales liées à une tâche attentionnelle avant et après une exposition lumineuse intense (>7000lux) de 21min. L’amélioration de l’éveil subjectif induite par la lumière est liée à une augmentation de l’activité thalamique. De plus, la lumière augmente l’activité d’un réseau de régions corticales impliquées dans la tâche, prévenant les diminutions d’activités observées en obscurité continue. Ces augmentations déclinent en quelques minutes après l’arrêt de la lumière, en suivant des dynamiques diverses spécifiques à chaque région. Ces premiers résultats suggèrent que, via une modulation de l’activité de structures sous-corticales régulant l’éveil, la lumière peut promouvoir dynamiquement l’activité corticale de réseaux impliqués dans un processus cognitif non-visuel. La deuxième étude montre que de courtes expositions (18min) à des lumières monochromatiques (3x1013ph/cm2/s) bleues (470nm) ou vertes (550nm) affectent différemment les réponses cérébrales liées à une tâche de mémoire de travail. La lumière bleue augmente les réponses cérébrales ou, du moins, prévient les diminutions observées sous lumière verte dans des cortex pariétaux et frontaux impliqués dans la mémoire de travail, ainsi que dans le thalamus. Ces résultats montrent qu’une lumière monochromatique peut rapidement influencer les fonctions cognitives et suggèrent que ces effets sont induits via un système de photoréception qui utilise la mélanopsine. Ces résultats démontrent qu’une exposition lumineuse diurne peut moduler l’activité cérébrale non-visuelle liée à deux fonctions cognitives complexes. La lumière agit rapidement en fonction de la région cérébrale et de la longueur d’onde considérées. Les sensibilités aux différentes longueurs d’ondes suggèrent l’implication d’un système de photoréception utilisant la mélanopsine. XXX. Les résultats suggèrent également une implication étendue de la lumière dans la régulation des fonctions cérébrales chez l’homme et soutiennent son utilisation pour contrecarrer la somnolence diurne et traiter des désordres circadiens et psychiatriques. [less ▲]

Detailed reference viewed: 46 (7 ULg)
Full Text
See detailCalcul de la résistance au feu d'ouvrages d'art en intégrant l'éclatement du béton
Franssen, Jean-Marc ULg; Hanus, François ULg; Dotreppe, Jean-Claude ULg

Scientific conference (2007, July 06)

Les ouvrages en béton présentent en général une bonne résistance au feu. Toutefois, dans certaines situations, l'apparition de phénomènes d'éclatement peut mener à une réduction rapide et marquée de la ... [more ▼]

Les ouvrages en béton présentent en général une bonne résistance au feu. Toutefois, dans certaines situations, l'apparition de phénomènes d'éclatement peut mener à une réduction rapide et marquée de la résistance des éléments concernés. Les tunnels, qui sont souvent soumis à des incendies de très forte intensité, subissent très souvent la perte de leurs premières couches intérieures pouvant conduire à la mise à nu des armatures. dans cet article, on montre comment le logiciel SAFIR peut être utilisé pour effectuer une analyse de risque en intégrant des valeurs plausibles de l'éclatement. ce concept sera illustré par l'examen d'une structure particulière. [less ▲]

Detailed reference viewed: 358 (11 ULg)
Full Text
See detailIntergrated Exercices on Environmental Issues : a presentation of an interdisciplinary learning process at the University of Liège
Melard, François ULg

Scientific conference (2007, July 04)

Presentation of an interdisciplinary seminar in a master of environmental Sciences and Management at the University of Liège.

Detailed reference viewed: 14 (1 ULg)
Full Text
Peer Reviewed
See detailLe fonctionnement concret d’un quartier de détention pour femmes : ressorts organisationnels et implications sur l’identité personnelle des surveillants
Dubois, Christophe ULg

in SociologieS (2007)

The organizational mechanisms of the “even and odd phenomenon” in a Belgian prison for women and its implications on the prison guards identities. <br />The “even and odd prison guards phenomenon” is ... [more ▼]

The organizational mechanisms of the “even and odd phenomenon” in a Belgian prison for women and its implications on the prison guards identities. <br />The “even and odd prison guards phenomenon” is famous all around Belgian prisons. The following case study will specifically focus on how the staff is distributed in two homogeneous guard teams: one is referred to as “socially-oriented” and the other as "security-oriented". First, we will determine the mechanisms of the organizational rules and regulation within the prison district. Second, we will concentrate on how prison guards construct their own personal identity. We believe this work will contribute to a better understanding of the prison guard profession. [less ▲]

Detailed reference viewed: 75 (23 ULg)
Full Text
See detailSeismic study of the Alpha Centauri binary system using the minimisation algorithm of Levenberg-Marquarth
Ozel, N.; Dupret, Marc-Antoine ULg; Baglin, A.

in SF2A-2007: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics held in Grenoble, France, July 2-6, 2007, Eds.: J. Bouvier, A. Chalabaev, and C. Charbonnel, p.545 (2007, July 01)

Thanks to the CoRoT mission, we are going to get seismic data of very high precision for many stars. Throughout the method of asteroseismology these data will allow us to constrain the physical ... [more ▼]

Thanks to the CoRoT mission, we are going to get seismic data of very high precision for many stars. Throughout the method of asteroseismology these data will allow us to constrain the physical description of stellar interiors with unprecedented precision. In this context, we have developed a general tool which allows us to find stellar models fitting a set of seismic constraints (the oscillations frequencies) and non-seismic constraints (e.g. the luminosity, the effective temperature, ...). This tool follows the algorithm of Levenberg-Marquarth which seeks the fundamental parameters of the stellar model (e.g. the mass, the age, the helium abundance, the mixing-length parameter,ldots). We apply it to a specific case: the alpha Cen binary system. Taking into account all observational constraints available for this binary system, we succeed to find models entering between the one or two sigma error box of the observational constraints. [less ▲]

Detailed reference viewed: 16 (1 ULg)
Full Text
See detailFirst Results from SuperWASP
Street, R. A.; Collier Cameron, A.; Maxted, P. et al

in Transiting Extrapolar Planets Workshop (2007, July 01)

We present a summary of the first results from the SuperWASP survey, including the detection of two new transiting exoplanets. We summarize our candidate selection procedure and the process by which we ... [more ▼]

We present a summary of the first results from the SuperWASP survey, including the detection of two new transiting exoplanets. We summarize our candidate selection procedure and the process by which we eliminated many false positives prior to radial velocity observations carried out with the Sophie spectrograph at the Observatoire de Haute-Provence. These data confirmed the discovery of two new transiting hot Jupiters, while rejecting 23 other targets. The two confirmed planets, WASP-1b & WASP-2b, respectively orbit F7V and K1V host stars with periods of 2.52 days and 2.15 days. The mass of WASP-1b is constrained to the range 0.80-0.98 M_{Jup} and the planet appears to be `bloated' with a radius of at least 1.33 R_{Jup}. WASP-2b has a mass between 0.81-0.95 M_{Jup} and a radius in the range 0.65-1.26 R_{Jup}. [less ▲]

Detailed reference viewed: 15 (1 ULg)
Full Text
See detailDECPHOT: An Optimal Deconvolution-based Photometric Reduction Method
Gillon, Michaël ULg; Magain, Pierre ULg; Chantry, Virginie ULg et al

in Transiting Extrapolar Planets Workshop (2007, July 01)

A high accuracy photometric reduction method is needed to take full advantage of the potential of the transit method for the detection and characterization of exoplanets, especially in deep crowded fields ... [more ▼]

A high accuracy photometric reduction method is needed to take full advantage of the potential of the transit method for the detection and characterization of exoplanets, especially in deep crowded fields. In this context, we present DECPHOT, a new deconvolution-based photometry algorithm able to deal with a very high level of crowding and large variations of seeing. It also increases the resolution of astronomical images, an important advantage for the discrimination of false positives in transit photometry. [less ▲]

Detailed reference viewed: 69 (18 ULg)
Full Text
See detailThe asteroseismic analysis of the pulsating sdB Feige 48 revisited
Van Grootel, Valérie ULg; Charpinet, Stéphane; Fontaine, Gilles et al

Conference (2007, July)

We present a new detailed analysis of the short period pulsating sdB star Feige 48, based on the same observations than in our previous work (Charpinet et al., 2005, A&A 443, 251) but with our new codes ... [more ▼]

We present a new detailed analysis of the short period pulsating sdB star Feige 48, based on the same observations than in our previous work (Charpinet et al., 2005, A&A 443, 251) but with our new codes including the rotation of the star. Feige 48 is supposed to be a relatively fast rotator, showing a fine structure in its pulsation spectrum about 28 µHz on three groups in the 9 frequencies. On the other side, Feige 48 belongs to a close binary system (likely with a white dwarf) where the orbital period is 9.02 +/- 0.03h (S. O'Toole 2004). With our new codes including the rotation (for a given rotation law, we calculate associated multiplets for each frequency with the perturbative approach on the first order), avoiding us to make assumptions about the m=0 modes, we were able to fit all the 9 periods together, leading to sligthly different estimations for the structural parameters of Feige 48 than in our previous work. Moreover, the rotation of the star is found to be solid with a period of 32,540s <=> 9.038h, very close to the orbital period of the system determined by spectroscopy, confirming the reasonable assumption that the system is tidally locked. In this context, it was possible to exclude that Feige 48 has a fast rotating core in term of much poorer merit functions. [less ▲]

Detailed reference viewed: 6 (1 ULg)