Biomass production in experimental grasslands of different species richness during three years of climate warming

in Biogeosciences Discussions (2007), 4

Here we report on the single and combined impacts of climate warming and species richness on the biomass production in experimental grassland communities. Projections of a future warmer climate have ... [more ▼]

Here we report on the single and combined impacts of climate warming and species richness on the biomass production in experimental grassland communities. Projections of a future warmer climate have stimulated studies on the response of terrestrial ecosystems to this global change. Experiments have likewise addressed the importance of species numbers for ecosystem functioning. There is, however, little knowledge on the interplay between warming and species richness. During three years, we grew experimental plant communities containing one, three or nine grassland species in 12 sunlit, climate-controlled chambers in Wilrijk, Belgium. Half of these chambers were exposed to ambient air temperatures (unheated), while the other half were warmed by 3 degrees C (heated). Equal amounts of water were added to heated and unheated communities, so that warming would imply drier soils if evapotranspiration was higher. Biomass production was decreased due to warming, both aboveground (-29%) and belowground (-25%), as negative impacts of increased heat and drought stress in summer prevailed. Complementarity effects, likely mostly through both increased aboveground spatial complementarity and facilitative effects of legumes, led to higher shoot and root biomass in multi-species communities, regardless of the induced warming. Surprisingly, warming suppressed productivity the most in 9-species communities, which may be attributed to negative impacts of intense interspecific competition for resources under conditions of high abiotic stress. Our results suggest that warming and the associated soil drying could reduce primary production in many temperate grasslands, and that this will not necessarily be mitigated by efforts to maintain or increase species richness. [less ▲]

SHIP2 controls PtdIns(3,4,5)P3 and PKB activity in response to oxidative stress

in Cellular Signalling (2007), 19

Reactive oxygen species (ROS) are known to be involved in redox signalling pathways that may contribute to normal cell function as well as disease progression. The tumour suppressor PTEN and the inositol ... [more ▼]

Reactive oxygen species (ROS) are known to be involved in redox signalling pathways that may contribute to normal cell function as well as disease progression. The tumour suppressor PTEN and the inositol 5-phosphatase SHIP2 are critical enzymes in the control of PtdIns(3,4,5)P(3) level. It has been reported that oxidants, including those produced in cells such as macrophages, can activate downstream signalling via the inactivation of PTEN. The present study evaluates the potential impact of SHIP2 on phosphoinositides in cells exposed to sodium peroxide. We used a model of SHIP2 deficient mouse embryonic fibroblasts (MEFs) stimulated by H(2)O(2): at 15 min, PtdIns(3,4,5)P(3) was markedly increased in SHIP2 -/- cells as compared to +/+ cells. In contrast, no significant increase in PtdIns(3,4)P(2) could be detected at 15 or 120 min incubation of the cells with H(2)O(2) (0.6 mM). PKB activity was also upregulated in SHIP2 -/- cells as compared to +/+ cells in response to H(2)O(2). SHIP2 add back experiments in SHIP2 -/- cells confirm its critical role as a lipid phosphatase in the control of PtdIns(3,4,5)P(3) level in response to H(2)O(2). We conclude that SHIP2 lipid phosphatase activity plays an important role in the metabolism PtdIns(3,4,5)P(3) which is demonstrated in oxygen stressed cells [less ▲]

L'"étranger" au pays de sumer à l'époque de la troisième dynastie d'Ur

in Riaud, Jean (Ed.) L'étranger dans la Bible et ses lectures (2007)

L’Art mosan: Liège et son pays à l’époque romane (du XIe au XIIIe siècle)

Book published by Editions du Perron (2007)

Du XIe au XIIIe siècle, le pays de Liège connut un essor économique et artistique sans précédent. Sur le territoire du vaste diocèse de Liège, le long de la Meuse - qui a donné son nom à l'art mosan - s ... [more ▼]

Du XIe au XIIIe siècle, le pays de Liège connut un essor économique et artistique sans précédent. Sur le territoire du vaste diocèse de Liège, le long de la Meuse - qui a donné son nom à l'art mosan - s'est développé un art créatif et prestigieux. Ce volume rédigé, sous la direction de Benoît Van den Bossche et avec la collaboration de Jacques Barlet, par de grands spécialistes européens et américains offre un large panorama de cette production artistique, replacée dans son contexte historique, politique et économique. Tenant compte des acquis de la recherche de ces vingt dernières années et des perspectives qu'ils ouvrent, il explore l'architecture, l'orfèvrerie, la sculpture, les manuscrits, la vitrerie, la céramique, la numismatique, l'épigraphie, la musique et l'armurerie. [less ▲]

Ionospheric and geomagnetic conditions during periods of degraded GPS position accuracy : 2. RTK events during disturbed and quiet geomagnetic conditions

in Advances in Space Research (2007), 39(5), 881-888

A seven-year survey of Campylobacter contamination in meat at different production stages in Belgium

in International Journal of Food Microbiology (2007), 116(1), 35-45

The presence of Campylobacter was assessed in different samples of poultry, pork and beef meat and carcasses from slaughterhouses, production plants and retail level. An introductory study from 1997 to ... [more ▼]

The presence of Campylobacter was assessed in different samples of poultry, pork and beef meat and carcasses from slaughterhouses, production plants and retail level. An introductory study from 1997 to 1999, had the purpose of establishing the optimum dilution to detect changes in prevalence and allowed a semi-quantitative estimation of poultry and pork contamination. Following this, between 2000 and 2003, 4254 samples were taken in order to study the trends. The poultry matrixes represented the greatest number and the most highly contaminated samples, with 30.9% (in 0.01 g) positive samples, 18.7% (in 1 g), 46.9% (in 25 g) and 19.6% (in 0.01 g) for broiler carcasses, broiler fillets, prepared chicken and layer carcasses, respectively. Broiler carcasses and fillets sampled at retail level were significantly less contaminated than samples from production plants. Pork, beef and veal samples were rarely contaminated and, where contamination existed, it was at a low prevalence (maximum 5.0%). The high and unvarying prevalence of Campylobacter in poultry necessitates the implementation of intervention measures at the primary production level, in addition to methods of minimizing cross-contamination at the processing level. A survey plan in line with the present study could be used in the future to monitor the effects of the planned measures and performance objectives and to follow the evolution of Campylobacter contamination at all stages of the food chain, in accordance with European legislation. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

Spondylodiscite compliquée d'un abcès du psoas

in Revue Médicale Suisse (2007), 3(101), 620-621

Computed tomography anatomy of the equine metacarpo-phalangeal joint

Poster (2007)

Pharmacologie clinique des bisphosphonates : revue de littérature axée sur le tiludronate chez le cheval.

in Annales de Médecine Vétérinaire (2007), 151

Présentation D-STAR - Micro-satellite (Leodium) & station radio-amateur ULg

Scientific conference (2007)