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See detailQuantifications naturelles projectivement équivariantes
Radoux, Fabian ULg

Scientific conference (2006, September 28)

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See detailQue les 4x4 arrêtent leur char
Balthasar, Jean-Pierre; Collignon, Fabrice; De Wit, Pierre et al

Article for general public (2006)

Des 4x4 dans la ville, est-ce bien raisonnable? Ce qui est certain, c'est que les SUV et leurs conducteurs représentent pour les autres usagers de la voie publique un danger disproportionné. Un article ... [more ▼]

Des 4x4 dans la ville, est-ce bien raisonnable? Ce qui est certain, c'est que les SUV et leurs conducteurs représentent pour les autres usagers de la voie publique un danger disproportionné. Un article récent du «British Medical Journal» rapporte que les conducteurs de SUV (Sport Utility Vehicle ou véhicule utilitaire de sport; on désigne ici ces véhicules 4x4 de luxe très à la mode) sont quatre fois plus nombreux à conduire en téléphonant (l'appareil à la main, sans «mains-libres») que la moyenne des conducteurs. Ils sont aussi plus nombreux à conduire sans ceinture. Le sentiment de sécurité procuré par le véhicule inciterait le conducteur à prendre plus de risques. [less ▲]

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See detailFeasibility study of the modernization of Wielingen class frigates
Marchal, Jean ULg; Hage, André ULg; Dessart, Christophe et al

(2006, September 25)

The research group MRN04 has made a study of modernization of frigates of the Belgian Navy. The modernization includes fitting out of a landing area for an 11 tonnes helicopter, modifying the ... [more ▼]

The research group MRN04 has made a study of modernization of frigates of the Belgian Navy. The modernization includes fitting out of a landing area for an 11 tonnes helicopter, modifying the superstructure to solve the problems of cracks and reducing the radar cross section. The proposal of the group MRN04 consists of widening and stiffness the stern deck in order to permit landing of a helicopter, surrounding the existing superstructure by a new envelop having a better furtivity. The resistance of the helicopter landing area and the rigidity of the superstructure has been estimated by structural computations by finite elements method, which permits to choose the most adequate structure. Once the weight of the new elements is known, a new estimation of the weight is established. It permits to calculate the draft and the trim, and serves as the data to calculate the ship resistance. In fact, the speed of the frigate, as a crucial point, should not decrease too much. The ship resistance will be obtained by means of model tests in the towing tank in the University of Liège. The study shows the possibility to lay out a landing area for a helicopter of 11 tonnes as well as to decrease significantly the radar cross section, without severe reduction of the frigate speed. [less ▲]

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See detailTranscriptional activation of cyclooxygenase-2 by tumor suppressor p53 requires nuclear factor-kappaB
Benoit, Valérie; de Moraes, E.; Dar, N. A. et al

in Oncogene (2006), 25(42), 5708-5718

Overexpression of cyclooxygenase-2 (Cox-2) is thought to exert antiapoptotic effects in cancer. Here we show that the tumor suppressor p53 upregulated Cox-2 in esophageal and colon cancer cell lines by ... [more ▼]

Overexpression of cyclooxygenase-2 (Cox-2) is thought to exert antiapoptotic effects in cancer. Here we show that the tumor suppressor p53 upregulated Cox-2 in esophageal and colon cancer cell lines by inducing the binding of nuclear factor-kappaB (NF-kappaB) to its response element in the COX-2 promoter. Inhibition of NF-kappaB prevented p53 induction of Cox-2 expression. Cooperation between p53 and NF-kappaB was required for activation of COX-2 promoter in response to daunomycin, a DNA-damaging agent. Pharmacological inhibition of Cox-2 enhanced apoptosis in response to daunomycin, in particular in cells containing active p53. In esophageal cancer, there was a correlation between Cox-2 expression and wild-type TP53 in Barrett's esophagus (BE) and in adenocarcinoma, but not in squamous cell carcinoma (P < 0.01). These results suggest that p53 and NF-kappaB cooperate in upregulating Cox-2 expression, promoting cell survival in inflammatory precursor lesions such as BE. [less ▲]

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See detailXMM-Newton observations of the massive colliding wind binary and non-thermal radio emitter Cyg OB2#8A [O6If+O5.5III(f)]
De Becker, Michaël ULg; Rauw, Grégor ULg; Sana, H. et al

in Monthly Notices of the Royal Astronomical Society (2006), 371(3), 1280-1294

We report on the results of four XMM-Newton observations separated by about ten days from each other of Cyg OB2 #8A [O6If + O5.5III(f)]. This massive colliding wind binary is a very bright X-ray emitter ... [more ▼]

We report on the results of four XMM-Newton observations separated by about ten days from each other of Cyg OB2 #8A [O6If + O5.5III(f)]. This massive colliding wind binary is a very bright X-ray emitter-one of the first X-ray emitting O-stars discovered by the Einstein satellite-as well as a confirmed non-thermal radio emitter whose binarity was discovered quite recently. The X-ray spectrum between 0.5 and 10.0 keV is essentially thermal, and is best fitted with a three-component model with temperatures of about 3, 9 and 20 MK. The X-ray luminosity corrected for the interstellar absorption is rather large, i.e. about 1034 erg s(-1). Compared to the 'canonical' L-X/L-bol ratio of O-type stars, Cyg OB2 # 8A was a factor of 19-28 overluminous in X-rays during our observations. The EPIC spectra did not reveal any evidence for the presence of a non-thermal contribution in X-rays. This is not unexpected considering that the simultaneous detections of non-thermal radiation in the radio and soft X-ray (below 10.0 keV) domains is unlikely. Our data reveal a significant decrease in the X-ray flux from apastron to periastron with an amplitude of about 20 per cent. Combining our XMM Newton results with those from previous ROSAT-PSPC and ASCA-SIS observations, we obtain a light curve suggesting a phase-locked X-ray variability. The maximum emission level occurs around phase 0.75, and the minimum is probably seen shortly after the periastron passage. Using hydrodynamic simulations of the wind-wind collision, we find a high X-ray emission level close to phase 0.75, and a minimum at periastron as well. The high X-ray luminosity, the strong phase-locked variability and the spectral shape of the X-ray emission of Cyg OB2 # 8A revealed by our investigation point undoubtedly to X-ray emission dominated by colliding winds. [less ▲]

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See detailOn the nature of the hard X-ray source IGR J2018+4043
Bykov, Andrei Mikhailovich; Krassilchtchikov, Alexandre Mikhailovich; Uvarov, Yuri Alexandrovich et al

in Astrophysical Journal (2006), 649(1, Part 2), 21-24

We found a very likely counterpart to the recently discovered hard X-ray source IGR J2018 + 4043 in the multiwavelength observations of the source field. The source, originally discovered in the 20-40 keV ... [more ▼]

We found a very likely counterpart to the recently discovered hard X-ray source IGR J2018 + 4043 in the multiwavelength observations of the source field. The source, originally discovered in the 20-40 keV band, is now confidently detected also in the 40-80 keV band, with a flux of (1.4 +/- 0.4) x 10(-11) ergs cm(-2) s(-1). A 5 ks Swift observation of the IGR J2018 + 4043 field revealed a hard pointlike source with an observed 0.5-10 keV flux of 3.4(-0.8)(+0.7) x 10(-12) ergs cm(-2) s(-1) (90% confidence level) at alpha = 20(h)18(m)38(s).55, delta = +40 degrees 41'00.4" (with a 4".2 uncertainty). The combined Swift-INTEGRAL spectrum can be described by an absorbed power-law model with photon index Gamma = 1.3 +/- 0.2 and N-H = 6.1(-2.2)(+3.3) x 10(22) cm(-2). In archival optical and infrared data we found a slightly extended and highly absorbed object at the Swift source position. There is also an extended VLA 1.4 GHz source peaked at a beamwidth distance from the optical and X-ray positions. The observed morphology and multiwavelength spectra of IGR J2018 + 4043 are consistent with those expected for an obscured accreting object, i.e., an AGN or a Galactic X-ray binary. The identification suggests possible connection of IGR J2018 + 4043 to the bright gamma-ray source GEV J2020 + 4023 detected by COS B and CGRO EGRET. [less ▲]

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See detailRecent investigations on the behaviour of buildings after the loss of a column
Demonceau, Jean-François ULg; Luu, Nguyen Nam Hai ULg; Jaspart, Jean-Pierre ULg

in Dubina, Dan; Ungureanu, Viorel (Eds.) Steel: a new and traditional material for building (2006, September 20)

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional events. According to Eurocodes and some ... [more ▼]

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under exceptional events. According to Eurocodes and some different 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. An European RFCS project entitled “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 events through an appropriate robustness. In particular, one substructure test simulating the loss of a column in a composite building will be performed at Liège University. The present paper described first analytical and numerical studies carried out at Liège University as part of this European project. [less ▲]

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See detailUn été exceptionnel ?
Balthasar, Jean-Pierre; Collignon, Fabrice; De Wit, Pierre et al

Article for general public (2006)

Quel été ! Que de records ! Après l'été 2003, le plus chaud jamais observé en Europe au cours de ces cinq derniers siècles, le mois de juillet 2006 a de nouveau pulvérisé les records de températures ... [more ▼]

Quel été ! Que de records ! Après l'été 2003, le plus chaud jamais observé en Europe au cours de ces cinq derniers siècles, le mois de juillet 2006 a de nouveau pulvérisé les records de températures enregistrés en Belgique depuis 1833, avec près de 6°C au dessus de la normale. Le mois d'août exécrable fut par contre le plus sombre depuis le début des observations météorologiques en Belgique. Et le centre de la ville de Liège, comme d'autres localités du pays, a été fortement inondé à deux reprises en six semaines suite à des pluies diluviennes que certains qualifient de tropicales. [...] [less ▲]

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See detailOptimisation objective de paramètres en écoulements turbulents à surface libre sur maillage multibloc
Erpicum, Sébastien ULg

Doctoral thesis (2006)

The chronology of the theoretical and numerical researches outlined in this text is closely linked to our attachment to the physical modelling and to the practical concerns related to important hydraulic ... [more ▼]

The chronology of the theoretical and numerical researches outlined in this text is closely linked to our attachment to the physical modelling and to the practical concerns related to important hydraulic projects. The various applications carried out daily in the HACH , several of the being presented here, enabled to identify the ways to improve the existing numerical models of WOLF , as well as needs in new representation potentialities. The most of the developments described in this text were born from there, with as main objective to increase the capacities of the HACH’s models to help to the management and the design of hydraulic constructions. The hydraulic structures design, and the main part of the practical problems related to free surface flows hydrodynamics, requires both large and small scales studies, with reliable models locally suited to the represented phenomena, and thus variable in a single study depending on the particular point examined. On another hand, the shape and working optimization of hydraulic structures requires robust calibration tools allowing an objective approach. The latter have to be linked to simulation software with modelling capacities and computation times in agreement with the optimization requirements. Both these assessments specify the framework of the researches of this thesis and are at the roots of the definition of the objectives of this work. The first chapters of developments aim to describe the numerical framework of the WOLF package, and more particularly the 1D and 2D models. The rationalization of the computation times for large scale one-dimensional simulations is improved at this stage by implementing in the 1D solver an implicit time integration scheme in parallel to the existing explicit one. Similarly, some improvements have been brought to the solver WOLF2D. They concern the automatic extension of the computation domain regarding the wet and dry cells, the treatment of the slope and roughness source terms with an energetic approach, the water volume conservation as well as the reorganization of the equations resolution scheme in order to be totally free in the choice of the mathematical model to solve. The enrichment of the modelling potentialities of the WOLF software is then pursued by setting, implementing and applying an original turbulence model suited to the specific characteristics of the depth integrated flow modelling. In order to get over the computer and modelling limitations inherent in the use of a single mesh size to model a 2D domain, developments have been carried out to allow the realisation of two-dimensional computations on a structured Cartesian grid composed of several areas with different mesh sizes. In the same way, developments have been carried out to use the whole of the mathematical models available in WOLF2D simultaneously and automatically in a single simulation. The ultimate step of these developments consisted in linking the 1D and the 2D models in a single computation. Following all these steps of developments of hydrodynamic models, a suitable tool for parameters automatic calibration has been set up. Usable with any solver of the WOLF package, it allows the calibration of the whole of the physical parameters present in the hydrodynamic solvers, as well as the resolution of any calibration or optimization problem with these models. The final parallelisation of this Genetic Algorithms based tool opens the door to complex applications, such as the hydraulic design of structures on the basis of two-dimensional simulations of free surface turbulent flows on multiblock grid. At each step, the validation of the developments is rigorously performed through the comparison of the numerical results with those from test cases, theoretical or experimental, original or from the literature. Several practical applications examples illustrate the whole of the developed modelling potentialities and prove their applicability and efficiency facing the most of practical problems encountered by hydraulic engineers. [less ▲]

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See detailBulletin agrométéorologique - Août 2006
Tychon, Bernard ULg; Ozer, Pierre ULg; De Longueville, Florence ULg et al

in Bulletin Agrométéorologique (2006), 5(5),

L’année 2006 restera dans les annales comme étant une année exceptionnelle au niveau météorologique tant par son printemps froid que par son mois de juillet très sec et son mois d’août particulièrement ... [more ▼]

L’année 2006 restera dans les annales comme étant une année exceptionnelle au niveau météorologique tant par son printemps froid que par son mois de juillet très sec et son mois d’août particulièrement pluvieux. Ces conditions exceptionnelles rendent très délicates les prévisions de rendement. Il faut signaler que les rendements estimés sont ceux sur pieds et ils ne prennent pas en considération les pertes dues aux mauvaises conditions de récolte. Les rendements prévus pour les principales cultures de printemps restent très proches des moyennes calculées sur les 5 dernières années. [less ▲]

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See detailL'a priori fonctionnel. Étude de l'influence de Wittgenstein sur la pensée de Michel Bitbol
Pieret, Denis ULg

Master's dissertation (2006)

Un même constat unit Wittgenstein et Bitbol, l’un le dresse vis-à-vis du langage et l’autre vis-à-vis de la physique classique : des présupposés dus à la forme prédicative de la proposition nous poussent ... [more ▼]

Un même constat unit Wittgenstein et Bitbol, l’un le dresse vis-à-vis du langage et l’autre vis-à-vis de la physique classique : des présupposés dus à la forme prédicative de la proposition nous poussent à chercher la substance derrière le substantif. Ce que Wittgenstein montre, et que Bitbol voit dans les bouleversements apportés par la mécanique quantique, c’est que le point de vue divin que l’on pouvait prétendre adopter, était en réalité l’illusion d’un point de vue. Même si Kant nous avait déjà mis en garde contre cette illusion, l’usage du comme si pour maintenir l’idée de nature comme idéal régulateur permettait de constituer une physique qui, que l’on fût dupe ou non, ambitionnait de donner une "image de l’univers assez complète pour englober vraiment l’observateur-théoricien en train de dépeindre l’univers". Mais les obstacles que dresse la mécanique quantique rendent désormais ce projet illusoire. La position du réaliste scientifique se révèle être une tentative impossible pour prendre sur le monde un "point de vue de nulle part", comme le dit Putnam. [less ▲]

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See detailRecherche de symbioses chimiosynthétiques et/ou digestives chez des crustacés associés aux bois coulés
Hoyoux, Caroline ULg

Master of advanced studies dissertation (2006)

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See detailDéveloppement de modèles analytiques pour la prédiction du comportement élastique des assemblages mécaniques à broches dans la construction en bois
Ly, Dong Phuong Lam ULg

Doctoral thesis (2006)

A general procedure for the evaluation of the mechanical properties of structural joints, named “component method”, is now available from intensive research works at the European level. This procedure ... [more ▼]

A general procedure for the evaluation of the mechanical properties of structural joints, named “component method”, is now available from intensive research works at the European level. This procedure allows the analytical prediction of the resistance, but also of the stiffness and the deformation capacity, of structural joints under external forces (axial or shear forces, bending moments …). The component method is nowadays integrated as a reference procedure in two European de-sign codes, respectively for steel structures (EC3 [EN1993]) and steel-concrete composite structures (EC4 [EN1994]). However, its potential scope is much larger and present studies are aimed to apply to situations as joints in fire, joints under seismic loading, joints under exceptional loads (Robustness Project) …. More recently, a research project [CTI-2004] has succeeded in applying the component method to the investigation of the elastic behaviour of mechanical joints in timber construction. That is the result of the collaboration of CTIB-TCHN (Belgian Institute for Wood Technology) and University of Liège. The main principle of the component method is the following: • identification of constitutive components subjected to tension, compression or shear in the joint; • determination of the mechanical behaviour of these individual components; • "assembling" components so as to derive the mechanical properties of the whole joint. In the present paper, timber joints with dowel fasteners are considered. Two components may be identified: • "dowel" component (dowel fastener in bending and shear); • embedding component (timber member in embedding). The "dowel" component is known from past researches, whereas little information is available for the embedding component. EC5 [EN1995] proposes formulation to predict the behaviour for joints composed of these two components; but it only depends on two factors: the dowel diameter and the timber density. The influence probably significant of the grain direction (material strongly anisotropy) and the thickness of the connected members are for instance neglected. Experimental, numerical and analytical investigations have recently been performed by Uni-versity of Liège in collaboration with CTIB-TCHN so as to propose another formulation more precise for joints. Experimental results, performed by CTIB-TCHN, have been used as refer-ence for the development of numerical model and, then, analytical model. The application of the component method to the prediction of the elastic behaviour of timber joints consist of two steps: • "local" investigation on components that is to develop analytical models for the pre-diction of the elastic behaviour of components; • "global" investigation on joints that is to develop analytical models for the prediction of the elastic behaviour of joints. The application of the component method to timber joints with dowel fasteners is a first step towards the use of this concept in future to others mechanical joints (screw, punched metal plate, nail, bolt …). In this case, others components may be derived to cover the field of ap-plication expected. [less ▲]

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See detailAh, la bonne pomme...
Ozer, Pierre ULg

Article for general public (2006)

Certifiée «bio», elle a fait 15 000 kilomètres en avion, kérosène compris. Elles sont belles, rondes, colorées et appétissantes à l'envi. Elles nous viennent d'Argentine ou de Nouvelle-Zélande. Ce sont ... [more ▼]

Certifiée «bio», elle a fait 15 000 kilomètres en avion, kérosène compris. Elles sont belles, rondes, colorées et appétissantes à l'envi. Elles nous viennent d'Argentine ou de Nouvelle-Zélande. Ce sont les pommes certifiées «bio» que nous proposent actuellement nos supermarchés... [less ▲]

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See detailInforme de investigación (misión de septiembre 2005 a abril 2006): Los usos del territorio en la Vía Parque Isla de Salamanca (Colombia), un diagnóstico para el desarrollo ecoturístico.
Escobar Jimenez, Kelly ULg

Report (2006)

Analizar las posibilidades que existen en un Espacio Habitado de Alto Valor Ecológico (EHAVE) para proponer el ecoturismo como un tipo de desarrollo sostenible y participativo y como una forma de ... [more ▼]

Analizar las posibilidades que existen en un Espacio Habitado de Alto Valor Ecológico (EHAVE) para proponer el ecoturismo como un tipo de desarrollo sostenible y participativo y como una forma de valorización de la naturaleza y la cultura, requiere de un diagnóstico de los usos ancestrales y contemporáneos que las poblaciones locales hacen en el territorio. En la Vía Parque Isla de Salamanca las prácticas y los saberes de las poblaciones locales y de otros actores involucrados en el manejo del territorio pueden estar relacionadas o ir contraposición con la utilización turística del lugar, es por esta razón que intentamos conocerlas y mirar sus potencialidades culturales, sociales e institucionales, así como, analizar los escenarios de negociación y conflicto a los que se enfrenta un pretendido uso eco turístico del lugar. En este artículo se identifican tres usos del territorio que compiten con el uso turístico: subsistencia, investigación-conservación y explotación económica, cada uno de ellos es descrito y alternativamente relacionado con las actividades turísticas que se presentan en diferentes escenarios del parque natural que también son explicadas al detalle en la última sección del texto. [less ▲]

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See detailEscourgeon et Orge d'hiver fourragers
Monfort, Bruno; Herman, Jean-Luc; Couvreur, Luc et al

in Livre Blanc: Céréales - Gembloux - Informations avant les semis (2006, September 07)

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See detailLe froment d'hiver
Herman, Jean-Luc; Vancutsem, Françoise ULg; Couvreur, Luc et al

in Céréales Gembloux - Informations avant les semis (2006, September 07)

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See detailLa qualité des froments d'hiver en 2006?
Sinnaeve, Georges; Lenartz, Jonathan; Vancutsem, Françoise ULg et al

in Céréales Gembloux - Informations avant les semis (2006, September 07)

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