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See detailStructuration dans les milieux granulaires
Troupin, Charles ULg

Master's dissertation (2005)

L'objet de ce travail est l'étude des milieux granulaires soumis des oscillations sinusoïdales et des phénomènes de structurations qui peuvent s'y produire. Trois parties le composent : la première partie ... [more ▼]

L'objet de ce travail est l'étude des milieux granulaires soumis des oscillations sinusoïdales et des phénomènes de structurations qui peuvent s'y produire. Trois parties le composent : la première partie est une introduction générale o quelques propriétés des granulaires sont exposés et où quelques structures dissipatives sont comparées. La deuxième partie présente les différents modèles permettant de décrire les phénomènes de structurations dont traite le travail. La dernière partie consiste en une étude expérimentale réalisée au laboratoire du GRASP. L'étude des différents modèles a montré que, contrairement aux fluides ou aux solides, des équations d'évolution de la densité, la vitesse et la température n'étaient pas parfaitement établies, ceci étant du à la nature fortement dissipative des milieux granulaires. Une analyse du système a également révélé qu'une description de type "milieu continu" n'est pas parfaitement justifiée, car la séparation entre les échelles microscopiques et macroscopiques est assez floue dans les milieux granulaires. L'étude expérimentale a permis de reproduire la plupart des structurations décrites dans la littérature, malgré les nombreuses imperfections du dispositif employé (vibrations fournies par un haut-parleur). Quelques mesures de longueur d'onde des "patterns" en fonction de la fréquence ont été réalisées. L'étude des comportements d'une couche constituée de deux matériaux granulaires différents a révélé que les mêmes structurations que dans la couche homogène se produisent, les plus gros grains se plaçant sur au-dessus des plus petits. En conclusion, les milieux granulaires en général et des phénomènes de structuration en particulier sont des domaines très vastes en plein développements. Les aspects théorique, numérique et expérimental méritent chacun de faire l'objet de recherche. Ce travail permet de faire le point sur les connaissances actuelles dans le domaine et ouvre de nombreuses perspectives d'étude. [less ▲]

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See detailLe contexte d'édification du Sart Tilman
Frankignoulle, Pierre ULg

in Cahiers de l'Urbanisme (Les) (2005), (n°54-55), 18-23

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See detailTransmission of an undiagnosed sarcoma to recipients of kidney and liver grafts procured in a non-heart beating donor
Detry, Olivier ULg; De Roover, Arnaud ULg; de Leval, Laurence ULg et al

in Liver Transplantation (2005), 11(6), 696-699

Transmission of an undiagnosed cancer with solid organ transplantation is a rare but dreadful event. In this paper the authors report the transmission of an undiagnosed sarcoma to recipients of kidney and ... [more ▼]

Transmission of an undiagnosed cancer with solid organ transplantation is a rare but dreadful event. In this paper the authors report the transmission of an undiagnosed sarcoma to recipients of kidney and liver grafts procured in a Maastricht category 3 non-heart beating donor. To the authors' knowledge this case is the first report of such a transmission with a liver graft procured in a non-heart beating donor. The cancer transferal was diagnosed I year after transplantation in the recipients of the liver and of one kidney. The liver recipient died from multiple organ failure after a failed attempt of tumor resection. The kidney recipient underwent immunosuppression withdrawal and transplantectomy. Non-heart beating donors should not be particularly at risk for undiagnosed cancer transmission if the procurement is performed according to the same rules of careful inspection of the abdominal and thoracic organs. After diagnosis of donor cancer transmission, kidney recipients should have the graft removed, and immunosuppression should be interrupted. The management of liver graft recipients is very difficult in this setting, and long-term survival was very rarely reported. [less ▲]

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See detailObservation n°5 (cas particulier de Parsonage & Turner)
Wang, François ULg; Kaux, Jean-François ULg; Dive, Dominique ULg

in Correspondances en Nerf & Muscle (2005, June), (Numéro spécial), 20-23

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See detailMoems Packaging for Harsh environments
Loicq, Jerôme ULg

Conference (2005, May 31)

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See detailSensibilisation à une autre pédagogie : ateliers de pédagogie active
VIERSET, Viviane ULg

Book published by Presses de l'Université de Marrakech (2005)

Description des Ateliers de pédagogie et outils de travail pour professeur-relais en pédagogie universitaire. Préface du professeur JM De Ketele

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See detailThe effect of youth employment quotas on the job finding rates of young people in Wallonia
Fonder, Muriel; Lejeune, Bernard ULg

Conference (2005, May 26)

In april 2000, the Belgian federal government launched a special labor market program, whose prominent characteristic was the obligation for companies to occupy in their labor force a certain quota of ... [more ▼]

In april 2000, the Belgian federal government launched a special labor market program, whose prominent characteristic was the obligation for companies to occupy in their labor force a certain quota of young people. Based on a sample of more 100,000 young Walloon job seekers (Wallonia is the French-speaking region of Belgium), the aim of this paper is to evaluate whether or not this program has really improved the youth insertion in the labour market, compared to what would have prevailed in the absence of the program. The effect of the program is evaluated through discrete duration models, and estimated by ‘difference in differences’, looking at the individual trajectory on the labor market of young job seekers, before and after the setting up of the program, for the program target group and for a control group. The empirical results show that the program had a modest positive effect for mid-skilled job seekers, but very little effect for unskilled job seekers. On the other hand, as it could be expected, a strong deadweight effect is observed for the skilled young job seekers. [less ▲]

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See detailEvaluation of a high-resolution regional climate simulation over Greenland
Lefebre, Filip; Fettweis, Xavier ULg; Gallée, Hubert et al

in Climate Dynamics (2005), 25(1), 99-116

A simulation of the 1991 summer has been performed over south Greenland with a coupled atmosphere–snow regional climate model (RCM) forced by the ECMWF re-analysis. The simulation is evaluated with in ... [more ▼]

A simulation of the 1991 summer has been performed over south Greenland with a coupled atmosphere–snow regional climate model (RCM) forced by the ECMWF re-analysis. The simulation is evaluated with in-situ coastal and ice-sheet atmospheric and glaciological observations. Modelled air temperature, specific humidity, wind speed and radiative fluxes are in good agreement with the available observations, although uncertainties in the radiative transfer scheme need further investigation to improve the model’s performance. In the sub-surface snow-ice model, surface albedo is calculated from the simulated snow grain shape and size, snow depth, meltwater accumulation, cloudiness and ice albedo. The use of snow metamorphism processes allows a realistic modelling of the temporal variations in the surface albedo during both melting periods and accumulation events. Concerning the surface albedo, the main finding is that an accurate albedo simulation during the melting season strongly depends on a proper initialization of the surface conditions which mainly result from winter accumulation processes. Furthermore, in a sensitivity experiment with a constant 0.8 albedo over the whole ice sheet, the average amount of melt decreased by more than 60%, which highlights the importance of a correctly simulated surface albedo. The use of this coupled atmosphere–snow RCM offers new perspectives in the study of the Greenland surface mass balance due to the represented feedback between the surface climate and the surface albedo, which is the most sensitive parameter in energy-balance-based ablation calculations. [less ▲]

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See detailLa Chine et les nouveaux médias
Hermans, Michel ULg

Article for general public (2005)

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See detailSynthesis of new substituted poly(ε-caprolactone)s by comination of ring-opening polymerization, atom transfer radical addition and click reaction
Lecomte, Philippe ULg; Riva, Raphaël ULg; Schmeits, Stephanie ULg et al

Poster (2005, May 19)

During the last few years, a great research effort has been devoted to the synthesis of aliphatic polyesters, e.g. poly(ε-caprolactone) and polylactides. Indeed, their remarkable properties of ... [more ▼]

During the last few years, a great research effort has been devoted to the synthesis of aliphatic polyesters, e.g. poly(ε-caprolactone) and polylactides. Indeed, their remarkable properties of biodegradability and biocompatibility pave the way to many new applications in the biomedical field and as substitutes for non degradable polymers. In order to tailor the polyester properties, the grafting of functional groups along the polymer backbone is highly desirable. For the last few years, CERM has reported on the synthesis and the (co)polymerization of novel ε-caprolactones γ-substituted by various functional groups, e.g., ketal, ketone, olefin, protected alcohol and carboxylic acid. Nevertheless, the grafting of a specific functional group onto the aliphatic polyester backbone requires the synthesis of the parent substituted ε-caprolactone. There is accordingly a need for a strategy that would use a unique substituted ε-caprolactone, followed by derivatization by well-established reactions, so making available a wide range of pendent functional groups, polymeric or not. The derivatization reactions have however to be quantitative under mild conditions to prevent the aliphatic polyester from degrading. Moreover, these reactions must be compatible with the functional groups of interest, e.g., hydroxyl and carboxylic acid, in order to avoid the use of cumbersome protection/deprotection reactions. This communication aims at reporting that a-chloro-e caprolactone (αCLεCL) can be easily copolymerized with εCL into poly(αCLεCL-co-εCL) copolymers, which are precursors for various aliphatic polyesters, by using either Atom Transfer Radical Addition (ATRA) or Click reactions. The number of steps is limited whatever the "Click" or the "ATRA" strategy under consideration. In both cases, mild conditions have been found, such that degradation is minimized. Pendent hydroxyl, carboxylic acid and epoxide groups have been attached without using any protection/deprotection reaction. This strategy has been implemented for the synthesis of amphiphilic poly(εCL-g-ethylene oxide) graft copolymers, that have been used to prepare poly(D,L-lactide) nanoparticles for drug delivery applications. [less ▲]

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See detailBulletin agrométéorologique - Avril 2005
Tychon, Bernard ULg; Ozer, Pierre ULg; De Longueville, Florence ULg et al

in Bulletin Agrométéorologique (2005), 4(1), 1-5

L’hiver météorologique (décembre 2004 à février 2005) peut être caractérisé de normal, tout comme les mois de mars et avril qui lui ont succédé. La situation des cultures d’hiver est également normale ... [more ▼]

L’hiver météorologique (décembre 2004 à février 2005) peut être caractérisé de normal, tout comme les mois de mars et avril qui lui ont succédé. La situation des cultures d’hiver est également normale, avec des rendements qui s’annoncent généralement supérieurs à ceux de 2003 et de 2004 pour le froment d’hiver. Dans le cas de l’orge d’hiver, les estimations de rendements n’atteignent pas les résultats de 2004 mais dépassent largement les rendements observés en 2003. Il est prématuré d’émettre des prévisions pour les cultures printanières. [less ▲]

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See detailSuivi de l'état de l'AGRIculture WALlonne par TELédétection (projet SAGRIWATEL)
Tychon, Bernard ULg; Istasse, Alain

Conference (2005, May 11)

Le projet de recherche et développement sur le « Suivi de l’Etat l’Agriculture Wallonne par Télédétection (SAGRIWATEL) » entamé en janvier 2003 est réalisé dans le cadre d’une étroite collaboration entre ... [more ▼]

Le projet de recherche et développement sur le « Suivi de l’Etat l’Agriculture Wallonne par Télédétection (SAGRIWATEL) » entamé en janvier 2003 est réalisé dans le cadre d’une étroite collaboration entre une équipe de scientifiques provenant de différents organismes de recherche wallons (Centre Wallon de Recherches Agronomiques, Université de Liège, Université Catholique de Louvain, Faculté Universitaire des Sciences Agronomiques de Gembloux) et l’Administration Wallonne de l’Agriculture (DGA). Il vise à mettre en place pour l’Administration Wallonne de l’Agriculture des outils de suivi de l’agriculture tant pour ce qui concerne ses activités de production que pour ce qui concerne ses activités en lien avec la protection du milieu (mesures agro-environnementales). Ces outils sont conçus, selon les cas, pour du contrôle, de l’encadrement ou encore pour le suivi global de l’évolution de l’agriculture à l’échelle de la région wallonne. Le système vise à valoriser la base de données du Système Intégré de Gestion et de Contrôle (SIGC) qui est en mesure de fournir des informations pour des applications autres que celles pour lesquelles il a été conçu. En association avec de l’information satellite ou aérienne et des modèles de croissance des cultures une série d’applications concrètes ont été élaborées pour : - la prévision des productions agricoles - la délimitation de zones à stress hydrique - le repérage et l’estimation de surfaces ou de longueurs de bandes enherbées, haies,… - le repérage de la couverture hivernale des sols - le repérage du sens du labour - le suivi des successions culturales - le suivi de la diversité des cultures - l’évolution de la taille des parcelles - … Le système bénéficie de l’apport du SIGC graphique qui fonctionne en Belgique de manière opérationnelle depuis 1997. L’utilisation originale qui est faite du SIGC dans cette étude constitue une nouvelle valorisation de ce système cartographique au départ destiné uniquement à du contrôle des déclarations des agriculteurs. L’approche est intéressante car elle permet un meilleur suivi de l’état de l’agriculture pour l’Administration avec un outil dont elle a la maîtrise, lui permettant de répondre rapidement aux demandes, notamment de l’Europe. En outre, l’outil s’est révélé rapidement opérationnel et adaptable à de nouvelles demandes ce qui constitue un avantage non négligeable quand l’on analyse les fréquentes évolutions de la PAC de ces dernières années. Enfin, l’approche optimise les informations transmises par les agriculteurs lors de leur déclaration PAC, leur évitant des pertes de temps dans des demandes de renseignement répétitives conduisant en quelque sorte à une simplification administrative. L’accès à l’information au sein de la Direction Générale de l’Agriculture se fera via une interface WEB-GIS. Un prototype sera opérationnel dans moins de deux mois. Il est prévu qu’à terme, d’autres Institutions Wallonnes et les agriculteurs wallons euxmêmes puissent bénéficier de cette avancée technologique. [less ▲]

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See detailOptical spectroscopy of X-Mega targets - V. The spectroscopic binary HD 93161 A and its visual companion HD 93161 B
Nazé, Yaël ULg; Antokhin, I. I.; Sana, H. et al

in Monthly Notices of the Royal Astronomical Society (2005), 359(2), 688-698

We present the analysis of an extensive set of high-resolution spectroscopic observations of HD 93161, a visual binary with a separation of 2 arcsec. HD 93161 A is a spectroscopic binary, with both ... [more ▼]

We present the analysis of an extensive set of high-resolution spectroscopic observations of HD 93161, a visual binary with a separation of 2 arcsec. HD 93161 A is a spectroscopic binary, with both components clearly detected throughout the orbit. The primary star is most probably of spectral type O8V, while the secondary is likely an O9V. We obtain the first orbital solution for this system, characterized by a period of 8.566 +/- 0.004 d. The minimum masses of the primary and secondary stars are 22.2 +/- 0.6 and 17.0 +/- 0.4 M-., respectively. These values are quite large, suggesting a high inclination of the orbit. The second object, HD 93161 B, displays an O6.5V(f) spectral type and is thus slightly hotter than its neighbour. This star is at first sight single but presents radial velocity variations. Finally, we study HD 93161 in the X-ray domain. No significant variability is detected. The X-ray spectrum is well described by a 2T model with kT(1) similar to 0.3 keV and kT(2) similar to 0.7 keV. The X-ray luminosity is rather moderate, without any large emission excess imputable to a wind interaction. [less ▲]

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See detailIndividual and combined effects of dosages of azoxystrobin and epoxiconazole in wheat
Moreau, Jean-Marc; Bodson, Bernard ULg; Maraite, H. et al

in Communications in Agricultural and Applied Biological Sciences (2005, May 10), 70(3), 91-99

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See detailSelectivity lists of pesticides to beneficial arthropods for IPM programs in carrot--first results.
Hautier, L.; Jansen, J.-P.; Mabon, N. et al

in Communications in Agricultural and Applied Biological Sciences (2005, May 10), 70(4), 547-558

In order to improve IPM programs in carrot, 7 fungicides, 12 herbicides and 9 insecticides commonly used in Belgium were tested for their toxicity towards five beneficial arthropods representative of most ... [more ▼]

In order to improve IPM programs in carrot, 7 fungicides, 12 herbicides and 9 insecticides commonly used in Belgium were tested for their toxicity towards five beneficial arthropods representative of most important natural enemies encountered in carrot: parasitic wasps- Aphidius rhopalosiphi (De Stefani-Perez) (Hym., Aphidiidae), ladybirds - Adalia bipunctata (L.) (Col., Coccinellidae), hoverfly - Episyrphus balteatus (Dipt., Syrphidae), rove beetle - Aleochara bilineata (Col., Staphyllinidae) and carabid beetle - Bembidion lampros (col., Carabidae). [less ▲]

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See detailDissolved Inorganic Carbon dynamics in the northern Bay of Biscay during a Coccolithophore bloom
Harlay, Jérôme ULg; van der Zee, Claar; Schiettecatte, Laure-Sophie et al

Poster (2005, May 02)

In the framework of the Belgian global change programme, we have developed a project devoted to the study of the inorganic carbon cycle in the Bay of Biscay where coccolithophore blooms occur frequently ... [more ▼]

In the framework of the Belgian global change programme, we have developed a project devoted to the study of the inorganic carbon cycle in the Bay of Biscay where coccolithophore blooms occur frequently. The study focuses on processes associated with the oceanic production and dissolution of calcium carbonate and related CO2 fluxes. Real time remote sensing allowed to localize the coccolithophore bloom that the R.V. Belgica visited in June 2004 during a multidisciplinary scientific cruise. We will present vertical profiles of pH, Talk, along with other parameters (salinity, temperature, chlorophyll a and phaeopigments) and 14C incorporation experiments. Inorganic carbon fluxes will be discussed in the photic zone, in correlation with the biological activity of phytoplankton (biological and carbonate pumps). [less ▲]

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See detailBallistic-diffusive heat conduction at nanoscale: GENERIC approach [rapid communication]
Grmela, M.; Lebon, Georgy ULg; Dauby, Pierre ULg et al

in Physics Letters A (2005), 339

Heat conduction in nanosize systems has to be studied in settings involving microscopic details that are not seen in the classical Fourier theory. G. Chen has suggested [Phys. Rev. Lett. 86 (2001) 2297] a ... [more ▼]

Heat conduction in nanosize systems has to be studied in settings involving microscopic details that are not seen in the classical Fourier theory. G. Chen has suggested [Phys. Rev. Lett. 86 (2001) 2297] a combination of the Cattaneo setting in which the velocity of the heat propagation is finite and the kinetic theory setting in which phonons are seen as heat carriers. In this Letter we show that if the Cattaneo and the kinetic theories are combined in a way that preserves the structure expressing their compatibility with thermodynamics (GENERIC structure) then both the Cattaneo and the kinetic equations become modified. The modified Cattaneo equations involve the term introduced by Chen and, in addition, new terms that are nonlinear in quantities that disappear at equilibrium. The kinetic equation is modified by new terms involving gradients of the heat flux and the local temperature. [less ▲]

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See detailConvection-pulsation coupling. I. A mixing-length perturbative theory
Grigahcène, A.; Dupret, Marc-Antoine ULg; Gabriel, Maurice ULg et al

in Astronomy and Astrophysics (2005), 434

We present in details a time-dependent convection treatment in the frame of the Mixing-Length Theory (MLT). Following the original ideas by Unno (1967, PASJ, 19, 140), this theory has been developed by ... [more ▼]

We present in details a time-dependent convection treatment in the frame of the Mixing-Length Theory (MLT). Following the original ideas by Unno (1967, PASJ, 19, 140), this theory has been developed by Gabriel et al. (1974, Bull. Ac. Roy. Belgique, Classe des Sciences, 60, 866) and Gabriel (1996, Bull. Astron. Soc. India, 24, 233). In this paper, we present it in a united form, we detail the basic derivations and approximations and give final improvements. A new perturbation of the energy closure equation is proposed for the first time, making it possible to avoid the occurrence of short wavelength spatial oscillations of the thermal eigenfunctions. This theory accounts for the perturbation of the convective flux, the turbulent Reynolds stress and the turbulent kinetic energy dissipation. It has been numerically implemented in a non-radial non-adiabatic pulsation code and the first results published in a Letter by Dupret et al. (2004a, A&A, 414, L17) indicate that the theory predicts the observed red border of the lower end of the instability strip and the driving mechanism of the recently discovered gamma Dor stars. [less ▲]

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See detailL'astronomie dans le monde
Manfroid, Jean ULg

Article for general public (2005)

A-t-on vu des planètes extrasolaires?, Sedna, Mars, Ceinture de Kuiper, L'anneau de Neptune Liberté en péril, Extinctions, GRBs, Collisions lointaines, Galaxie de la Grande Ourse, Sources de rayons gamma ... [more ▼]

A-t-on vu des planètes extrasolaires?, Sedna, Mars, Ceinture de Kuiper, L'anneau de Neptune Liberté en péril, Extinctions, GRBs, Collisions lointaines, Galaxie de la Grande Ourse, Sources de rayons gamma au centre de la Voie Lactée [less ▲]

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