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See detailObservation urbaine du quartier de Gerland à Lyon
Frankignoulle, Pierre ULg

Report (2008)

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See detailDoublecortin as a Marker of Adult Neuroplasticity in the Canary Song Control Nucleus Hvc
Balthazart, Jacques ULg; Boseret, Géraldine ULg; Konkle, A. T. et al

in European Journal of Neuroscience (2008), 27(4), 801-17

It is established that in songbirds the size of several brain song control nuclei varies seasonally, based on changes in cell size, dendritic branching and, in nucleus HVC, the incorporation of newborn ... [more ▼]

It is established that in songbirds the size of several brain song control nuclei varies seasonally, based on changes in cell size, dendritic branching and, in nucleus HVC, the incorporation of newborn neurons. In the developing and adult mammalian brain, the protein doublecortin (DCX) is expressed in postmitotic neurons and, as a part of the microtubule machinery, required for neuronal migration. We recently showed that in adult canaries, DCX-immunoreactive (ir) cells are present throughout the telencephalon, but the link between DCX and the active neurogenesis observed in songbirds remained uncertain. We demonstrate here that DCX labels recently born cells in the canary telencephalon and that, in parallel with changes in HVC volume, the number of DCX-ir cells is increased specifically in the HVC of testosterone-treated males compared with castrates, and in castrated testosterone-treated males paired with a female as compared with males paired with another male. The numbers of elongated DCX-ir cells (presumptive migrating neurons) and round multipolar DCX-ir cells (differentiating neurons) were also affected by the sex of the subjects and their photoperiodic condition (photosensitive vs photostimulated vs photorefractory). Thus, in canaries the endocrine state, as well as the social or photoperiodic condition independently of variation in steroid hormone action, affects the number of cells expressing a protein involved in neuronal migration specifically in brain areas that incorporate new neurons in the telencephalon. The DCX gene may be one of the targets by which testosterone and social stimuli induce seasonal changes in the volume of song nuclei. [less ▲]

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See detailFifty years of landscape evolution in Southwestern Mauritania by means of aerial photos
Niang, A. J.; Ozer, André ULg; Ozer, Pierre ULg

in Journal of Arid Environments (2008), 72(2), 97-107

South-western Mauritania is located in a semi-arid environment exposed to large rainfall variations and affected by a severe drought since the mid-1960s. The studied area includes the right bank of the ... [more ▼]

South-western Mauritania is located in a semi-arid environment exposed to large rainfall variations and affected by a severe drought since the mid-1960s. The studied area includes the right bank of the Senegal River and the southern extension of the Saharan sandy dunes and is based on the analysis of climatic data, field studies, and four aerial surveys realized since 1954. The climatic analysis shows that, after a strong decline of yearly rainfall started in the mid-1960s, a significant increase is observed from the early 1990s. In the meantime, dust storms frequency has dramatically increased while the threshold wind speed declined as a result of vegetation contraction. The comparison of the four mosaics of aerial photos reveals the major impact of both drought and human on recent environment changes with the strong decline of the forest, the reactivation of sandy soils and the apparition of large rice fields. If the increase of active dunes activity is likely to be a consequence of the persisting drought, forest decline is more likely to be attributed to fuel wood collection in a first time, then to the creation of rice fields since the late 1980s. Although the 2003 aerial photos show a timid return of vegetation in very limited and specific areas, field surveys show that wind erosion is still very important and water erosion is developing very rapidly because of the absence of vegetation cover. (C) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailMagnetocaloric effect in nano- and polycrystalline manganite La0.7Ca0.3MnO3
Pekala, Marek; Drozd, V.; Fagnard, Jean-François ULg et al

in Applied Physics A : Materials Science & Processing (2008), 90(2), 237-241

La0.7Ca0.3MnO3 samples were prepared in nano- and polycrystalline forms by the sol-gel and solid state reaction methods, respectively, and structurally characterized by synchrotron X-ray diffraction. The ... [more ▼]

La0.7Ca0.3MnO3 samples were prepared in nano- and polycrystalline forms by the sol-gel and solid state reaction methods, respectively, and structurally characterized by synchrotron X-ray diffraction. The magnetic properties determined by ac susceptibility and dc magnetization measurements are discussed. The magnetocaloric effect in this nanocrystalline manganite is spread over a broader temperature interval than in the polycrystalline case. The relative cooling power of the poly- and nanocrystalline manganites is used to evaluate a possible application for magnetic cooling below room temperature. [less ▲]

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See detailRemembering the Past and Imagining the Future in Schizophrenia
D'Argembeau, Arnaud ULg; Raffard, Stéphane; Van der Linden, Martial ULg

in Journal of Abnormal Psychology (2008), 117(1), 247-51

It has been suggested that patients with schizophrenia experience a distorted sense of continuity of self across time. However, temporal aspects of self-processing have received little empirical attention ... [more ▼]

It has been suggested that patients with schizophrenia experience a distorted sense of continuity of self across time. However, temporal aspects of self-processing have received little empirical attention in schizophrenia. In this study, the authors investigated schizophrenic patients' ability to generate specific mental images of their personal past and future. Results showed that patients recalled fewer specific past events than did healthy controls and were even more impaired in generating specific future events. These deficits were associated with positive symptoms but were not associated with negative symptoms or with performances on verbal fluency tasks. It is suggested that schizophrenic patients' failures to project themselves into specific past and future episodes might be related to difficulties in retrieving contextual details from memory, as well as disturbance of the sense of subjective time. [less ▲]

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See detailTotal Joint Replacement after Glucosamine Sulphate Treatment in Knee Osteoarthritis: Results of a Mean 8-Year Observation of Patients from Two Previous 3-Year, Randomised, Placebo-Controlled Trials
Bruyère, Olivier ULg; Pavelka, K.; Rovati, L. C. et al

in Osteoarthritis and Cartilage (2008), 16(2), 254-60

OBJECTIVE: To assess the incidence of Total Joint Replacement (TJR) during the long-term follow-up of patients with knee osteoarthritis (OA) formerly receiving treatment with glucosamine sulphate or ... [more ▼]

OBJECTIVE: To assess the incidence of Total Joint Replacement (TJR) during the long-term follow-up of patients with knee osteoarthritis (OA) formerly receiving treatment with glucosamine sulphate or placebo. METHODS: Knee OA patients participating in two previous randomised, placebo-controlled, double-blind, 3-year trials of glucosamine sulphate and receiving treatment for at least 12 months, were systematically contacted to participate in a long-term follow-up retrospective assessment of the incidence of total knee replacement. RESULTS: Out of 340 patients with at least 12 months of treatment, 275 (i.e., 81%) could be retrieved and interviewed for the present evaluation: 131 formerly on placebo and 144 on glucosamine sulphate. There were no differences in baseline disease characteristics between groups or with the patients lost to follow-up. The mean duration of follow-up was approximately 5 years after trial termination and treatment discontinuation, making up a total of 2178 patient-years of observation (including treatment and follow-up). Total knee replacement had occurred in over twice as many patients from the placebo group, 19/131 (14.5%), than in those formerly receiving glucosamine sulphate, 9/144 (6.3%) (P=0.024, chi-square test), with a Relative Risk that was therefore 0.43 (95% confidence interval (CI): 0.20-0.92), i.e., a 57% decrease compared with placebo. The Kaplan Meier/Log-Rank test survival analysis confirmed a significantly decreased (P=0.026) cumulative incidence of total knee replacements in patients who had received glucosamine sulphate. A pharmacoeconomic analysis in a subgroup of subjects suggested that patients formerly on glucosamine sulphate had recurred to less symptomatic medications and use of other health resources than those from the placebo group during the last year of follow-up. CONCLUSIONS: Treatment of knee OA with glucosamine sulphate for at least 12 months and up to 3 years may prevent TJR in an average follow-up of 5 years after drug discontinuation. [less ▲]

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See detailCombien de litres de kérosène dans notre assiette?
Ozer, Pierre ULg; Perrin, Dominique ULg

Article for general public (2008)

L’aviation commerciale émet près de 5% des émissions mondiales de CO2 dues aux activités humaines. Sa part ne fait qu’augmenter et le développement de la mobilité internationale des biens et des personnes ... [more ▼]

L’aviation commerciale émet près de 5% des émissions mondiales de CO2 dues aux activités humaines. Sa part ne fait qu’augmenter et le développement de la mobilité internationale des biens et des personnes laisse présager une prolongation des tendances historiques de croissance du transport aérien. Avec comme conséquence, une assiette de plus en plus lourde en CO2 lorsque nos aliments proviennent de contrées lointaines par voie aérienne (kérosène). [less ▲]

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See detailNew methods of prenatal screening for trisomy 21
Capelle, Xavier ULg; Schaaps, Jean-Pierre ULg; Foidart, Jean-Michel ULg

in Revue Médicale de Liège (2008), 63(2), 82-6

Down syndrome is the most commonly recognized genetic cause of mental retardation. The risk of trisomy 21 is directly related to maternal age which can be viewed as the first screening test in the 1970's ... [more ▼]

Down syndrome is the most commonly recognized genetic cause of mental retardation. The risk of trisomy 21 is directly related to maternal age which can be viewed as the first screening test in the 1970's. New strategies for Down syndrom, have emerged with higher sensitivity and lower false-positive rate. These strategies are based on sonographic and maternal serum markers. The most specific but complex strategy is based on the integrated test, i.e., the integration of the quadruple test performed in the second trimester to the first trimester combined screening: for a 85% detection rate, the false positive rate is estimated to 0.9%. This strategy deprives the patient of an early diagnosis. Alternatives strategies do exist which can perform similar detection rate but with increasing false positive rate. To date Down syndrom, screening has not been coordinated by a national body; it would be usefull to ensure the sonographist formation, perform quality audit and decrease variations in practice. [less ▲]

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See detailThe Chitobiose-Binding Protein, DasA, Acts as a Link between Chitin Utilization and Morphogenesis in Streptomyces Coelicolor
Colson, Séverine ULg; van Wezel, G. P.; Craig, Matthias ULg et al

in Microbiology (2008), 154(Pt 2), 373-82

Streptomycetes are mycelial soil bacteria that undergo a developmental programme that leads to sporulating aerial hyphae. As soil-dwelling bacteria, streptomycetes rely primarily on natural polymers such ... [more ▼]

Streptomycetes are mycelial soil bacteria that undergo a developmental programme that leads to sporulating aerial hyphae. As soil-dwelling bacteria, streptomycetes rely primarily on natural polymers such as cellulose, xylan and chitin for the colonization of their environmental niche and therefore these polysaccharides may play a critical role in monitoring the global nutritional status of the environment. In this work we analysed the role of DasA, the sugar-binding component of the chitobiose ATP-binding cassette transport system, in informing the cell of environmental conditions, and its role in the onset of development and in ensuring correct sporulation. The chromosomal interruption of dasA resulted in a carbon-source-dependent vegetative arrest phenotype, and we identified a second DasR-dependent sugar transporter, in addition to the N-acetylglucosamine phosphotransferase system (PTS(GlcNAc)), that relates primary metabolism to development. Under conditions that allowed sporulation, highly aberrant spores with many prematurely produced germ tubes were observed. While GlcNAc locks streptomycetes in the vegetative state, a high extracellular concentration of the GlcNAc polymer chitin has no effect on development. The striking distinction is due to a difference in the transporters responsible for the import of GlcNAc, which enters via the PTS, and of chitin, which enters as the hydrolytic product chitobiose (GlcNAc(2)) through the DasABC transporter. A model explaining the role of these two essentially different transport systems in the control of development is provided. [less ▲]

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See detailBulk high-Tc superconductors with drilled holes: how to arrange the holes to maximize the trapped magnetic flux?
Lousberg, Grégory ULg; Ausloos, Marcel ULg; Vanderbemden, Philippe ULg et al

in Superconductor Science and Technology (2008), 21

Drilling holes in a bulk high-Tc superconductor enhances the oxygen annealing and the heat exchange with the cooling liquid. However, drilling holes also reduces the amount of magnetic flux that can be ... [more ▼]

Drilling holes in a bulk high-Tc superconductor enhances the oxygen annealing and the heat exchange with the cooling liquid. However, drilling holes also reduces the amount of magnetic flux that can be trapped in the sample. In this paper, we use the Bean model to study the magnetization and the current line distribution in drilled samples, as a function of the hole positions. A single hole perturbs the critical current flow over an extended region that is bounded by a discontinuity line, where the direction of the current density changes abruptly. We demonstrate that the trapped magnetic flux is maximized if the centre of each hole is positioned on one of the discontinuity lines produced by the neighbouring holes. For a cylindrical sample, we construct a polar triangular hole pattern that exploits this principle; in such a lattice, the trapped field is ∼20% higher than in a squared lattice, for which the holes do not lie on discontinuity lines. This result indicates that one can simultaneously enhance the oxygen annealing, the heat transfer and maximize the trapped field. [less ▲]

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See detailWhat is the Role for Regulatory T-Cells after Nonmyeloablative conditioning
Humblet-Baron, S.; CASTERMANS, Emilie ULg; Vanbellighen, J.-F. et al

in Biology of Blood & Marrow Transplantation (2008, February), 14(2), 136-137

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See detailPartially Segregated Neural Networks for Spatial and Contextual Memory in Virtual Navigation
Rauchs, G.; Orban, Pierre ULg; Balteau, Evelyne ULg et al

in Hippocampus (2008), 18(5), 503-518

Finding our way in a previously learned, ecologically valid environment concurrently involves spatial and contextual cognitive operations. The former process accesses a cognitive map representing the ... [more ▼]

Finding our way in a previously learned, ecologically valid environment concurrently involves spatial and contextual cognitive operations. The former process accesses a cognitive map representing the spatial interactions between all paths in the environment. The latter accesses stored associations between landmark objects and their milieu. Here, we aimed at dissociating their neural basis in the context of memory-based virtual navigation. To do so, subjects freely explored a virtual town for 1 h, then were scanned using fMRI while retrieving their way between two locations, under four navigation conditions designed to probe separately or jointly the spatial and contextual memory components. Besides prominent commonalities found in a large hippocampo-neocortical network classically involved in topographical navigation, results yield evidence for a partial dissociation between the brain areas supporting spatial and contextual components of memory-based navigation. Performance-related analyses indicate that hippocampal activity mostly supports the spatial component, whereas parahippocampal activity primarily supports the contextual component. Additionally, the recruitment of contextual memory during navigation was associated with higher frontal, posterior parietal and lateral temporal activity. These results provide evidence for a partial segregation of the neural substrates of two crucial memory components in human navigation, whose combined involvement eventually leads to efficient navigation behavior within a learned environment. (c) 2008 Wiley-Liss, Inc. [less ▲]

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See detailUtilisation des prises de vue aérienne à basse altitude pour le suivi des activités hydro-agricoles – Cas du Bassin du Kou
Wellens, Joost ULg; Diallo, M.; Dakouré, D. et al

Scientific conference (2008, January 29)

Le bassin du Kou, situé dans le sud-ouest du Burkina Faso, est depuis quelques décennies le théâtre de différentes formes de conflits liés à toute une série de problèmes que l’on rencontre généralement ... [more ▼]

Le bassin du Kou, situé dans le sud-ouest du Burkina Faso, est depuis quelques décennies le théâtre de différentes formes de conflits liés à toute une série de problèmes que l’on rencontre généralement dans des zones irriguées. Dans le bassin du Kou, les aménagements hydro-agricoles recensés couvrent une superficie otale de près de 3.200 ha ; il s’agit pour l’essentiel de périmètres privés formant la ceinture maraîchère et horticole de Bobo-Dioulasso et d’un grand périmètre de 1.200 ha réalisé par l’Etat à Bama et spécialisé dans la production du riz. Le développement d’une filière fruits et légumes sous l’impulsion de l’initiative privée est un trait caractéristique de la production irriguée dans la région. Outre l’abondance en eau liée à la présence de sources importantes, d’une nappe phréatique facilement exploitable, d’un cours d’eau pérenne et un hivernage à caractère sub-humide, la plupart des utilisateurs d’eau se retrouvent régulièrement en pénurie d’eau suite à l’extension non contrôlée de l’agriculture irriguée. Ceci a conduit les gestionnaires du bassin à rechercher des outils de contrôle et de suivi. A partir de plus de 300 prises de vue aérienne ‘amateurs’ à basse altitude, ayant une résolution de 0,8 m., une image d’occupation détaillée des sols a pu être élaborée. Des logiciels de mosaïquage, de traitement d’images et de SIG ont permis la construction d’une seule image géoréférencée. Les parcelles agricoles irriguées ont ainsi pu être délimitées. Leurs occupations ont été comparées et complétées avec les résultats d’un recensement hydro-agricole exhaustif organisé au même moment. Cette technique permet un suivi spatial des activités agricoles à moindre coût par rapport à l’acquisition des images satellites à haute résolution. L’approche est également moins sensible aux influences atmosphériques non-prévisibles dans la programmation des images satellites. Elle répond avec une précision largement suffisante aux objectifs de suivi et contrôle des parcelles irriguées demandés par les gestionnaires du bassin. [less ▲]

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See detailImproved one-dimensional numerical simulation of transient mixed flow in water pipes network
Kerger, François ULg; Archambeau, Pierre ULg; Erpicum, Sébastien ULg et al

in Proceedings of the 2nd ENVITAM PhD Day (2008, January 29)

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See detailStyle beyond Borders: Language in Recent Nigerian Fiction
Tunca, Daria ULg

Doctoral thesis (2008)

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