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See detailDimethyl sulfide and dimethylsulfoniopropionate profiles in sea ice during winter in the Weddell Sea
Uhlig, C.; Tison, J.-L.; Rintala, J. et al

Conference (2014, March)

This study presents profiles of the organic sulphur components dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in sea ice cores collected during the AWECS (Antarctic Winter Ecosytem Climate ... [more ▼]

This study presents profiles of the organic sulphur components dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) in sea ice cores collected during the AWECS (Antarctic Winter Ecosytem Climate Study) cruise on RV Polarstern (ANT29-6) in the Weddell Sea. DMS is a semi-volatile sulfur component and under discussion to be climate active, as its oxidation products might act as cloud condensation nuclei - thus cooling the atmosphere. It is produced by enzymatic cleavage of the precursor DMSP, which is synthesized by various types of phytoplankton and serves for example as compatible solute and cryoprotectant. Due to the physico-chemical conditions given, i.e. the high salinity and the icy matrix, sea ice as habitat favors production of high levels of DMSP by the inhabiting microalgae. DMSP and DMS are frequently found in high concentrations in sea ice during spring and summer. The aim of this study was to investigate DMS(P) levels in winter sea ice as data for the winter season is yet scarce, but is of importance for global budgeting. Preliminary results of our study show that DMS(P) production in sea ice in the Weddell Sea is also significant during winter. This stands in contrast to previous measurements in Arctic winter sea ice (CFL-IPY cruise in the Circumpolar Flaw Lead Polynya), where DMS(P) concentrations were very low. Possible explanations for the differences between DMS(P) levels in the Arctic and Antarctic might be the different snow cover and thus insulation, light regimes and also microbial community structure within the ice. DMS(P) levels were generally correlated with chlorophyll a concentrations, although the details are complex and seem to be influenced by species composition and species specific DMSP/Chla ratios. The DMS profiles mirrored the permeability of the sea ice following DMSP in the impermeable areas while showing losses to the ice surface and ice-water interface in the more permeable regions. Winter DMS(P) profiles are furthermore compared to data collected during the following spring cruise of RV Polarstern (ANT29-7) in the Weddell Sea. [less ▲]

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See detailThe Dimethylsulfide Cycle in the Eutrophied Southern North Sea: A Model Study Integrating Phytoplankton and Bacterial Processes
Gypens, N; Borges, Alberto ULg; Speeckaert, Gaëlle ULg et al

in Plos One (2014), 9(1)(e85862 DOI: 10.1371/journal.pone.0085862),

We developed a module describing the dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) dynamics, including biological transformations by phytoplankton and bacteria, and physico-chemical ... [more ▼]

We developed a module describing the dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) dynamics, including biological transformations by phytoplankton and bacteria, and physico-chemical processes (including DMS air-sea exchange). This module was integrated in the MIRO ecological model and applied in a 0D frame in the Southern North Sea (SNS). The DMS(P) module is built on parameterizations derived from available knowledge on DMS(P) sources, transformations and sinks, and provides an explicit representation of bacterial activity in contrast to most of existing models that only include phytoplankton process (and abiotic transformations). The model is tested in a highly productive coastal ecosystem (the Belgian coastal zone, BCZ) dominated by diatoms and the Haptophyceae Phaeocystis, respectively low and high DMSP producers. On an annual basis, the particulate DMSP (DMSPp) production simulated in 1989 is mainly related to Phaeocystis colonies (78%) rather than diatoms (13%) and nanoflagellates (9%). Accordingly, sensitivity analysis shows that the model responds more to changes in the sulfur:carbon (S:C) quota and lyase yield of Phaeocystis. DMS originates equally from phytoplankton and bacterial DMSP-lyase activity and only 3% of the DMS is emitted to the atmosphere. Model analysis demonstrates the sensitivity of DMS emission towards the atmosphere to the description and parameterization of biological processes emphasizing the need of adequately representing in models both phytoplankton and bacterial processes affecting DMS(P) dynamics. This is particularly important in eutrophied coastal environments such as the SNS dominated by high non-diatom blooms and where empirical models developed from data-sets biased towards open ocean conditions do not satisfactorily predict the timing and amplitude of the DMS seasonal cycle. In order to predict future feedbacks of DMS emissions on climate, it is needed to account for hotspots of DMS emissions from coastal environments that, if eutrophied, are dominated not only by diatoms. [less ▲]

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See detailDimethylsulfoniopropionate (DMSP) cell quota of key Southern North Sea spring diatoms and Phaeocystis globosa
Speeckaert, Gaëlle ULg; Gypens, Nathalie; Lancelot, Christiane et al

Poster (2015, April)

Dimethylsulfide (DMS) in the ocean results of complex transformations of dimethylsulfoniopropionate (DMSP) produced by phytoplankton under different controls, including microbial transformation pathways ... [more ▼]

Dimethylsulfide (DMS) in the ocean results of complex transformations of dimethylsulfoniopropionate (DMSP) produced by phytoplankton under different controls, including microbial transformation pathways. The phytoplankton composition is an important factor of variability due to the species dependence of the DMSP production and conversion to DMS. To better appraise the link between phytoplankton diversity and the DMS(P) cycling in the Southern North Sea we present measurements of the DMSP cell quota of key spring phytoplankton species (Skeletonema costatum, Thalassiosira rotula, Rhizosolenia delicatula, Asterionella glacialis, Nitzschia closterium, Chaetoceros debilis, Chaetoceros socialis and Phaeocystis globosa) isolated from the North Sea and maintained in non-limiting and axenic laboratory culture conditions. Results are discussed with regards to literature data and hypothesis currently used in DMS(P) biogeochemical models. [less ▲]

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See detailDiminution de l'hyperventilation d'exercise par le blocage des recepteurs beta-adrenergiques
Scheen, André ULg; Juchmes, J.; Cession-Fossion, A.

in Comptes Rendus des Séances de la Société de Biologie et de ses Filiales (1976), 170(1), 220-3

In normal subjects, beta-adrenergic blockage by propranolol or pindolol reduces exercise hyperventilation (40 to 60% VO2 max).

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See detailDiminution de la consommation maximum d'oxygene apres blocage des recepteurs beta-andrenergiques
Scheen, André ULg; Juchmes, J.; Lennes, G. et al

in Archives Internationales de Physiologie et de Biochimie (1976), 84(5), 915-23

VO2 max, maximum oxygen uptake, has been measured in 4 normal young men, before and after beta-adrenergic blockade (0.5 to 5 mg Pindolol by mouth). Pindolol induces bradycardia and reduces VO2 max. A ... [more ▼]

VO2 max, maximum oxygen uptake, has been measured in 4 normal young men, before and after beta-adrenergic blockade (0.5 to 5 mg Pindolol by mouth). Pindolol induces bradycardia and reduces VO2 max. A statistically significant positive correlation appears between posology of Pindolol and bradycardia, this posology and reduction of VO2 max, and finally between bradycardia and reduction of VO2 max. These correlations indicate that the reduction of VO2 max is best explained by a circulatory limitation of oxygen supply to active muscles. [less ▲]

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See detailDiminution de la secretion d'adrenaline au cours de la diete hypocalorique protelique chez l'obese.
Scheen, André ULg; Cession-Fossion, A.; Scheen, Myriam ULg et al

in Annales d'Endocrinologie (1981), 42(6), 531-6

The protein-supplemented fasting induces a progressive but moderate decrease in blood glucose (-26%) and a marked rise in plasma free fatty acids levels (+ 43%). Nevertheless the secretion of epinephrine ... [more ▼]

The protein-supplemented fasting induces a progressive but moderate decrease in blood glucose (-26%) and a marked rise in plasma free fatty acids levels (+ 43%). Nevertheless the secretion of epinephrine by the adrenal medulla, as indirectly estimated by the ratio of the basal urinary elimination to the recovery percentage from the urine of an epinephrine infusion, shows a significant decrease (- 36%) during the protein diet. Thus the enhanced lipolysis does not result from an adrenergic overactivity but merely depends upon the marked reduction in the plasma insulin level (- 38%). [less ▲]

Detailed reference viewed: 83 (1 ULg)
See detailDiminution de volume d'un macro-adénome à ACTH (silencieux) sous Cabergoline
Khalife, A.; Ronci, N.; Stevenaert, Achille ULg et al

in XVIIème Congrès de la Société Française d'Endocrinologie - Abstract book (1999)

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See detailLa diminution des intrants dans la production des céréales
Roisin, Christian; Goffart, Jean-Pierre; Frankinet, Marc et al

in Fumure et protection phytosanitaire des céréales (1999, February 24)

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See detailLa diminution des intrants dans la production des céréales
Roisin, Christian; Goffart, Jean-Pierre; Frankinet, Marc et al

in Fumure et protection phytosanitaire des céréales (1998, February 27)

Detailed reference viewed: 13 (0 ULg)
Peer Reviewed
See detailDinámica de la excreción natural del Virus de la Leucosis Bovina en semen de toros infectados naturalmente
Rossich, L.; Gutiérrez, G.; Rodriguez, Sabrina ULg et al

Poster (2008, September 22)

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See detailDinámica de la infección perinatal con Virus de la Leucosis Bovina en el rodeo lechero
Rossich, G.; Gutiérrez, G.; Rodriguez, Sabrina ULg et al

Poster (2008, September 22)

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See detailDinamica e pluralismo culturale nell’area di Bruxelles
Martiniello, Marco ULg

in Galissot, R.; Rivera, A. (Eds.) Pluralismo culturale in Europa (1995)

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See detailDinámicas locales de la conservación in situ de la diversidad de tubérculos andinos en el microcentro Candelaria
Terrazas, A. F.; Baudoin, Jean-Pierre ULg; Duran, G.

Conference given outside the academic context (2004)

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See detailDinamicas locales en la conservation in situ de la diversidad genética de tuberculos andinos cultivados en el microcentro de Candelaria
Terrazas, A. F.; Baudoin, Jean-Pierre ULg; Duran, G.

in Plant Genetic Resources Newsletter (2007), 152

Detailed reference viewed: 15 (10 ULg)
See detaildinanderie
George, Philippe ULg

in Dictionnaire d’Histoire de l’art du Moyen Age occidental (2009)

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See detailDinant/Anseremme: Trou Magrite
Noiret, Pierre ULg

in Chronique de l'Archéologie wallonne (1993), 1

Detailed reference viewed: 21 (0 ULg)