13 resultados para coral sol

em Université de Lausanne, Switzerland


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Reef-building corals form essential, mutualistic endosymbiotic associations with photosynthetic Symbiodinium dinoflagellates, providing their animal host partner with photosynthetically derived nutrients that allow the coral to thrive in oligotrophic waters. However, little is known about the dynamics of these nutritional interactions at the (sub)cellular level. Here, we visualize with submicrometer spatial resolution the carbon and nitrogen fluxes in the intact coral-dinoflagellate association from the reef coral Pocillopora damicornis by combining nanoscale secondary ion mass spectrometry (NanoSIMS) and transmission electron microscopy with pulse-chase isotopic labeling using [(13)C]bicarbonate and [(15)N]nitrate. This allows us to observe that (i) through light-driven photosynthesis, dinoflagellates rapidly assimilate inorganic bicarbonate and nitrate, temporarily storing carbon within lipid droplets and starch granules for remobilization in nighttime, along with carbon and nitrogen incorporation into other subcellular compartments for dinoflagellate growth and maintenance, (ii) carbon-containing photosynthates are translocated to all four coral tissue layers, where they accumulate after only 15 min in coral lipid droplets from the oral gastroderm and within 6 h in glycogen granules from the oral epiderm, and (iii) the translocation of nitrogen-containing photosynthates is delayed by 3 h. IMPORTANCE: Our results provide detailed in situ subcellular visualization of the fate of photosynthesis-derived carbon and nitrogen in the coral-dinoflagellate endosymbiosis. We directly demonstrate that lipid droplets and glycogen granules in the coral tissue are sinks for translocated carbon photosynthates by dinoflagellates and confirm their key role in the trophic interactions within the coral-dinoflagellate association.

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(Résumé de l'ouvrage) Résister aux extrémismes racistes et xénophobes : c'est dans une telle perspective que cet ouvrage s'inscrit. Ecrit à plusieurs voix, dans une pluralité d'approches historique, théologique, témoignages..., ce livre aide chaque lecteur à débusquer la tentation du rejet de l'autre, à se forger une opinion sur cette question, à nourrir ses engagements, à discerner les chemins de sa fidélité ; il appelle aussi chaque communauté à devenir lieu de guérison, de réconciliation et de pardon. Le livre ne fait pas de l'Evangile une valeur d'où le lecteur déduirait des valeurs opposables à l'idéologie de l'extrême droite, mais il le recentre sur l'essentiel : la rencontre avec le Christ, l'écoute de sa Parole qui toujours et d'abord appelle à sa propre conversion. C'est donc fondamentalement une parole théologique qui résonne ici."

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Times Cited: 0 References: 0 Citation MapAbstract : Background: Chemotherapy followed by autologous stem cell transplantation (ASCT) is the standard treatment for relapsed DLBCL. No study has compared salvage therapies and evaluated maintenance post ASCT.Methods: DLBCL CD 20+ in first relapse or pts refractory after first therapy were randomized between R ICE (rituximab, ifosfamide, etoposide, carboplatinum) or R DHAP (rituximab dexamethasone cytarabine cisplatinum). Responding patients received BEAM and ASCT then randomized between observation or maintenance with rituximab every 2 m for 1 yr (Gisselbrecht J Clin Oncol; 2010).Results: Analysis was made on 477 pts (R ICE: 243 pts; R DHAP: 234 pts): 255 relapses >12m, 213 refractory/early relapses; 306 pts had prior rituximab; secondary(s) IPI 0-1: 281 pts; s IPI 2-3:181pts. There was no difference in response rate between R ICE 63.6% and R DHAP 64.3%. There was no difference between R ICE and R DHAP at 4 yrs for EFS (26% vs 37% p=0.2) and OS (43% vs 51%, p=0.3). Factors affecting 4 yrs EFS, PFS and OS were: prior treatment with rituximab; early relapse< 12 m; s IPI 2-3. ASCT was performed in 255 pts and 242 randomized for maintenance: 122 pts rituximab (R), 120 pts observation (O). Distribution between R/O arms were respectively: median age 54 /53 yrs, Male 76/83; female 46/37; secondary IPI 0-1: 84/81; sIPI 2-3: 36/36. 89/76 relapses >12m., 33/41 refractory/early relapses. Median follow up was 44 m with 111 events. 4 yrs EFS was 52.8 % (CI 46-59) with 63% (CI 56-69) OS. There was no difference in EFS, PFS and OS between R and O arms. In multivariate analysis, sIPI2-3 significantly affected EFS, PFS, OS (p=0.0004). Women (83pts) had a better 4 yrs EFS 63% than male (159pts) 37% (p=0.01). The difference was only in the R arm (p=0.004). Gender was an independent prognostic factor in the R arm. Toxicity was mild with 12% SAE versus 4% for R /O respectively.Conclusions: There was no difference between R ICE and R DHAP and between post ASCT maintenance with R or O. Women did significantly better after ASCT with rituximab. Early relapses to upfront rituximab-based chemotherapy have a poor prognosis.

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La présente publication s'intéresse à un nouveau domaine de recherche des politiques environnementales. Elle se propose de théoriser et d'analyser le sous-sol comme une ressource naturelle potentiellement menacée. Le sous-sol suisse est depuis quelques années l'objet d'une forte intensification des demandes d'utilisation. Une pression démographique croissante s'exerce sur le Plateau, entrainant une augmentation du nombre d'infrastructures. Parallèlement, l'accroissement général de la valeur des terrains dans les villes pousse à une utilisation accrue de l'espace souterrain. Les progrès techniques rendent possible l'implantation d'infrastructures dans presque tous les contextes géologique. Enfin, la volonté politique et sociale de voir certains ouvrages ou substances, comme les déchets nucléaires, enterrés peut s'avérer déterminante. L'approche théorique privilégiée dans cette étude pour aborder le thème de la gestion durable de l'exploitation du sous-sol est celle, développée à l'IDHEAP, des « Régimes institutionnels de ressources » (RIR). Cette démarche se caractérise par sa volonté d'aborder la gestion d'une ressource de manière globale, en faisant fi des découpages territoriaux et institutionnels. Les résultats de l'analyse des juridictions cantonales et fédérales indiquent un risque clair de surexploitation de la ressource. En cause, le flou qui règne autour de la définition des droits de propriété du sous-sol et la faible coordination des politiques publiques concernées. L'étude se conclut sur une mise en perspective des possibilités de régulation qui s'offrent aux décideurs politiques, s'ils décident de prendre en charge le risque de surexploitation du sous-sol.

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In terrestrial snakes, many cases of intraspecific shifts in dietary habits as a function of predator sex and body size are driven by gape-limitation - and hence, are most common in species that feed on relatively large prey, and exhibit a wide body-size range. Our data on seasnakes reveal an alternative mechanism for intraspecific niche partitioning, based on sex-specific seasonal anorexia induced by reproductive activities. Turtle-headed seasnakes (Emydocephalus annulatus) on coral reefs in the New Caledonian Lagoon feed entirely on the eggs of demersal-spawning fishes. DNA sequence data (cytochrome b gene) on eggs that we palpated from stomachs of 37 snakes showed that despite this ontogenetic-stage specialization, the prey come from a taxonomically diverse array of species including damselfish (41% of samples, at least 5 species), blennies (41%, 4 species) and gobies (19%, 5 species). The composition of snake diets shifted seasonally (with damselfish dominating in winter but not summer), presumably reflecting seasonality of fish reproduction. That seasonal shift affects male and female snakes differently, because reproduction is incompatible with foraging. Adult female seasnakes ceased feeding when they became heavily distended with developing embryos in late summer, and males ceased feeding while they were mate-searching in winter. The sex divergence in foraging habits may be amplified by sexual size dimorphism; females grow larger than males, and larger snakes (of both sexes) feed more on damselfish (which often lay their eggs in exposed sites) than on blennies and gobies (whose eggs are hidden within narrow crevices). Specific features of reproductive biology of coral-reef fish (seasonality and nest type) have generated intraspecific niche partitioning in these seasnakes, by mechanisms different from those that apply to terrestrial snakes.

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The most prominent pattern in global marine biogeography is the biodiversity peak in the Indo-Australian Archipelago. Yet the processes that underpin this pattern are still actively debated. By reconstructing global marine paleoenvironments over the past 3 million years on the basis of sediment cores, we assessed the extent to which Quaternary climate fluctuations can explain global variation in current reef fish richness. Comparing global historical coral reef habitat availability with the present-day distribution of 6316 reef fish species, we find that distance from stable coral reef habitats during historical periods of habitat loss explains 62% of the variation in fish richness, outweighing present-day environmental factors. Our results highlight the importance of habitat persistence during periods of climate change for preserving marine biodiversity.

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[Table des matières] Résumé. Zusammenfassung. 1. Introduction. 2. Intégrer le genre dans les études de médecine : la " Success Story " néerlandaise. 2.1 En amont du projet national de 2002-2005. 2.1.1 L'étude pilote menée à l'Université Radboud à la fin des années 1990. 2.2 Integrating Gender into the Core Curriculum: le déroulement du projet national (2002-2005). 3. Enseignement prégradué en médecine à Lausanne: quelle place pour le genre ? Etat des lieux pour l'année académique 2009-2010. 3.1 Inventaire: quelques fleurs dans le désert ? 3.2 La situation lausannoise à l'aune des exigences du projet néerlandais. 3.3 L'organisation de l'enseignement à l'École de médecine de Lausanne suite à la réforme des années 2000. 3.4 Le développement des études genre à l'Université de Lausanne et en Suisse: quel impact sur la médecine ? 4. Inclure le genre dans les études prégraduées de médecine : le cadre au niveau suisse. 4.1 Quelles possibilités de soutien au niveau des instruments nationaux de pilotage de la formation médicale prégraduée ? 5. Quelles possibilités de transfert ? Des questions pour l'avenir. 5.1 Comment transférer l'expérience néerlandaise? 5.2 Quelles activités pourraient être entreprises au niveau national ? 6. Annexes.