18 research outputs found

    Electronic temperatures, densities and plasma X-ray emission of a 14.5 GHz Electron-Cyclotron Resonance Ion Source

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    We have performed a systematic study of the Bremsstrahlung emission from the electrons in the plasma of a commercial 14.5 GHz Electron-Cyclotron Resonance Ion Source. The electronic spectral temperature and the product of ionic and electronic densities of the plasma are measured by analyzing the Bremsstrahlung spectra recorded for several rare gases (Ar, Kr, Xe) as a function of the injected power. Within our uncertainty, we find an average temperature of ? 48 keV above 100W, with a weak dependency on the injected power and gas composition. Charge state distributions of extracted ion beams have been determined as well, providing a way to disentangle the ionic density from the electronic density. Moreover X-ray emission from highly charged argon ions in the plasma has been observed with a high-resolution mosaic crystal spectrometer, demonstrating the feasibility for high-precision measurements of transition energies of highly charged ions, in particular of the magnetic dipole (M1) transition of He-like of argon ions

    CLIMASTER: climatic change, farming systems, natural resources and regional development

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    CLIMASTER, is a comprehensive program built in a participative way, associating researchers, farmer organisations and water management offices, to tackle the issue of the interaction between the climatic change, the farming systems, the natural resources and the regional development. It concerns the 4 administrative regions of West France, Brittany, Basse Normandie, Poitou-Charentes and Pays de Loire, that present quite specific characteristics : Importance of coastal issues, large areas of wetlands; farming systems mainly devoted to animal breeding; water resources threatened by scarcity and anthropic impacts, environmental concerns. Although the interest of scientists on climatic changes focused rarely on this western region, it appears that farmers and water and natural resource managers in these regions have already to account for some impact of climatic changes, especially those linked to extreme conditions. The project is organised in 4 tasks. The first one attempts to assess the regional climatic changes (trend, increase of variability and extreme events). The second one analyses the way farmers account for climatic changes in their practices. The 3rd one analyses the impact of climatic changes on the natural resources, mainly quantitative and qualitative water resources, but also biodiversity. The last one analyses the position of farmers from the sociological and psycho-sociological perspectives. A series of cross seminars will be organised, focusing on some environmental objects, like wetlands, coastal issues, and the construction of management scenarios. One of the interests is to develop a shared perspective on the impact of climate changes between scientists, different stakeholders and local people. More than 10 research teams and 15 structures devoted to territorial development and farmer advising are involved in the project. The first steps of the project are described

    Landscape design for soir conservation under land use and climate change

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    Soils and landscapes evolve simultaneously. Soil evolution is controlled by redistribution and transformation processes influenced by topographic and climatic parameters, with also a major contribution of management strategies. The perennial landscape features have a strong influence on soil spatial distribution (geometry) and soil genesis. Building landscapes which enhance soil resilience to degradation processes and increase soil services appears as a promising way to adapt to forthcoming climatic and land use evolutions. The presentation aims to synthetize major results from a research program nicknamed Landsoil which focused on the evolution of agricultural soils over medium time scales (decades to centuries) in relation to changing conditions of land use and climate. Precise study of the soil 3D organization in three contrasted landscapes (Brittany, Touraine, Languedoc-Roussillon) enabled to link soil redistribution in space to landscape components (field geometry, hedges or ditches network) and their past evolution. A dynamic and high resolution spatial modeling approach was developed coupling erosion processes and soil organic matter evolution and was calibrated over past evolution using dating techniques (Cs137, C14, OSL). The resulting Landsoil model was afterwards applied in a prospective manner under different scenarios of land use and climate change over the 21th century. Indicators of soil vulnerability and soil resilience were defined and tested by the comparison of several prospective scenarios applied on a same landscape and by comparison of the contrasted landscape

    Protection IntĂ©grĂ©e des rotations avec Colza et blĂ© tendre : Conception et Ă©valuation multicritĂšres d’itinĂ©raires techniques Ă©conomes en produits phytosanitaires

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    Le projet PICOBLE avait pour objectif, en se plaçant Ă  l’échelle de l’itinĂ©raire technique, de contribuer Ă  la recherche de solutions permettant de rĂ©duire l’usage de produits phytosanitaires dans les systĂšmes de culture Ă  base de colza et de blĂ©. Il a permis de concevoir et de tester des ITK innovants pour diffĂ©rentes situations. Les rĂ©sultats obtenus concluent Ă  la possibilitĂ© d’une rĂ©duction des produits phytosanitaires de 30 Ă  40% sans affectation de la marge de l’agriculteur sur la base des hypothĂšses de prix prises, mais avec une rĂ©duction du volume de production de 10% pouvant affecter l’économie des filiĂšres avales. Les connaissances acquises permettent d’envisager de nouvelles pistes de rĂ©duction Ă  plus long terme mais elles nĂ©cessitent encore un travail considĂ©rable, il faudra en particulier aborder des Ă©chelles plus larges au niveau du systĂšme de culture ou du paysage.Integrated protection of crop rotation with winter oilseed rape (WOSR) and winter wheat: Conception and multicriteria evaluation of pesticides saver cropping practices The PICOBLE project was looking for knowledge and knowhow likely to contribute to a reduction of pesticides use in wheat and WOSR-based rotations, at the scale of annual cropping practices. New cropping techniques have been imagined, discussed and tested in the field before being assessed with a multi-criteria approach. A 30-40% reduction of the total amount of pesticides is possible, without X. Pinochet et al. 244 Innovations Agronomiques 28 (2013), 243-256 affecting the farmer economic result under given price hypothesis, but with a 10% reduction of the production, that might affect the economic competiveness of the connected industries. Results and knowledge produced during the project open new perspectives for further reductions on the longer term. Nevertheless, work is still needed and approaches have to be extended to cropping systems and landscapes scales

    Associations céréale-légumineuses multi-services

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    Depuis plusieurs dĂ©cennies, l’évolution de l’agriculture en France est, dans un certain nombre de rĂ©gions de grande culture et d’élevage marquĂ©e fortement par la simplification des assolements accompagnĂ©e d’un usage accru des intrants et la standardisation des itinĂ©raires techniques. Le challenge est maintenant de concevoir des agroĂ©cosystĂšmes plus diversifiĂ©s dans l’objectif d’une gestion Ă©cologique des parcelles cultivĂ©es devant se traduire par une amĂ©lioration de la productivitĂ© et la stabilitĂ© des systĂšmes face Ă  divers alĂ©as et la fourniture de diffĂ©rents services Ă©co-systĂ©miques. Ce projet a explorĂ© l’augmentation de la diversitĂ© cultivĂ©e au sein de la parcelle via des associations cĂ©rĂ©ale-lĂ©gumineuse. Il a montrĂ© la diversitĂ© des services que l’on peut en attendre en agriculture biologique et en agriculture conventionnelle, en systĂšme cĂ©rĂ©alier et en systĂšme d’élevage. Ces associations permettent de rĂ©pondre Ă  la fois Ă  des enjeux de production, de rĂ©duction des intrants, de rĂ©duction des impacts environnementaux des cultures, de stabilitĂ© face Ă  des alĂ©as biotiques et abiotiques. Le cƓur du projet a consistĂ© a testĂ© diffĂ©rents leviers d’actions pour aider Ă  l’orientation des performances de ces associations pour diffĂ©rents objectifs. Les atouts et contraintes d’adoption Ă  l’échelle des filiĂšres (notamment pour les collecteurs) ont Ă©tĂ© aussi mis en Ă©vidence et quantifiĂ©s

    Associations céréale-légumineuse multi-services

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    Depuis plusieurs dĂ©cennies, l’évolution de l’agriculture en France est, dans un certain nombre de rĂ©gions de grande culture et d’élevage marquĂ©e fortement par la simplification des assolements accompagnĂ©e d’un usage accru des intrants et la standardisation des itinĂ©raires techniques. Le challenge est maintenant de concevoir des agroĂ©cosystĂšmes plus diversifiĂ©s dans l’objectif d’une gestion Ă©cologique des parcelles cultivĂ©es devant se traduire par une amĂ©lioration de la productivitĂ© et la stabilitĂ© des systĂšmes face Ă  divers alĂ©as et la fourniture de diffĂ©rents services Ă©co-systĂ©miques. Ce projet a explorĂ© l’augmentation de la diversitĂ© cultivĂ©e au sein de la parcelle via des associations cĂ©rĂ©ale-lĂ©gumineuse. Il a montrĂ© la diversitĂ© des services que l’on peut en attendre en agriculture biologique et en agriculture conventionnelle, en systĂšme cĂ©rĂ©alier et en systĂšme d’élevage. Ces associations permettent de rĂ©pondre Ă  la fois Ă  des enjeux de production, de rĂ©duction des intrants, de rĂ©duction des impacts environnementaux des cultures, de stabilitĂ© face Ă  des alĂ©as biotiques et abiotiques. Le coeur du projet a consistĂ© a testĂ© diffĂ©rents leviers d’actions pour aider Ă  l’orientation des performances de ces associations pour diffĂ©rents objectifs. Les atouts et contraintes ’adoption Ă  l’échelle des filiĂšres (notamment pour les collecteurs) ont Ă©tĂ© aussi mis en Ă©vidence et quantifiĂ©s

    Mitral valve disease−morphology and mechanisms

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    International audienceMitral valve disease is a frequent cause of heart failure and death. Emerging evidence indicates that the mitral valve is not a passive structure, but−even in adult life−remains dynamic and accessible for treatment. This concept motivates efforts to reduce the clinical progression of mitral valve disease through early detection and modification of underlying mechanisms. Discoveries of genetic mutations causing mitral valve elongation and prolapse have revealed that growth factor signalling and cell migration pathways are regulated by structural molecules in ways that can be modified to limit progression from developmental defects to valve degeneration with clinical complications. Mitral valve enlargement can determine left ventricular outflow tract obstruction in hypertrophic cardiomyopathy, and might be stimulated by potentially modifiable biological valvular-ventricular interactions. Mitral valve plasticity also allows adaptive growth in response to ventricular remodelling. However, adverse cellular and mechanobiological processes create relative leaflet deficiency in the ischaemic setting, leading to mitral regurgitation with increased heart failure and mortality. Our approach, which bridges clinicians and basic scientists, enables the correlation of observed disease with cellular and molecular mechanisms, leading to the discovery of new opportunities for improving the natural history of mitral valve disease
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