78 research outputs found

    Study of the N=50 major shell effect close to 78^{78}Ni : First evidence of a weak coupling structure in 83_32^{83}\_{32}Ge_51\_{51} and three-proton configuration states in 81_31^{81}\_{31}Ga_50\_{50}

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    New levels were attributed to 81_31^{81}\_{31}Ga_50\_{50} and 83_32^{83}\_{32}Ge_51\_{51} which were fed by the ÎČ\beta-decay of their respective mother nuclei 81_30^{81}\_{30}Zn_51\_{51} and 83_31^{83}\_{31}Ga_52\_{52} produced by fission at the "PARRNe" ISOL set-up installed at the Tandem accelerator of the Institut de Physique Nucl\'eaire, Orsay. We show that the low energy structure of 81_31^{81}\_{31}Ga_50\_{50} and 83_32^{83}\_{32}Ge_51\_{51} can easily be explained within the natural hypothesis of a strong energy gap at N=50 and a doubly-magic character for 78^{78}Ni.Comment: 2 pages, pdf file, To be published in the Proceedings of "International Symposium on Structure of Exotic Nuclei and Nuclear Forces (SENUF 06)", March 2006, Tokyo, Japa

    Release properties of UCx_x and molten U targets

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    The release properties of UCx_x and molten U thick targets associated with a Nier- Bernas ion source have been studied. Two experimental methods are used to extract the release time. Results are presented and discussed for Kr, Cd, I and Xe

    Ion sources at GANIL

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    International audienceThe GANIL produces since many years heavy ion beams with Electron Cyclotron Resonance ion sources. Different facilities have been constructed during the last years in order to allow experiments in a large range of energy (from some tens of kV to 100 MeV/nucleon). The list of available ions has been greatly extended with the construction of the SPIRAL1 facility that produces and accelerates radioactives ions . An overview of the different developments made at GANIL for stable and radioactive ion beam production including the sources for the SPIRAL2 project is given in this paper

    UCx_x target design for the SPIRAL 2 project and the ALTO project

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    ACC NESTERInternational audienceTwo ways of production of radioactive beams using uranium carbide targets are taken into consideration: fission induced by fast neutrons and by bremsstrahlung radiation. For the SPIRAL 2 project, the fission of 238U in uranium carbide target will be induced by a neutron flow created by bombarding a carbon converter with a 40 MeV high intensity deuteron beam. Calculations and design of the target in order to reach 1013 fissions/s with good release time have been done. The second way is the photofission using an electron beam. In 2005 the ALTO project (AccĂ©lĂ©rateur LinĂ©aire AuprĂšs du Tandem d'Orsay) will give a 50 MeV/10ÎŒ\muA electron beam. This facility will allow more than 1011 fissions/s. In this case, the electron beam hits the target without converter. Calculations realised in order to estimate the production are used to choose the best target shape. For the two cases some R & D on targets to improve release is described

    Finding Homogeneity in Heterogeneity—A New Approach to Quantifying Landscape Mosaics Developed for the Lao PDR

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    A key challenge for land change science in general and research on swidden agriculture in particular, is linking land cover information to human–environment interactions over larger spatial areas. In Lao PDR, a country facing rapid and multi-level land change processes, this hinders informed policy- and decision-making. Crucial information on land use types and people involved is still lacking. This article proposes an alternative approach for the description of landscape mosaics. Instead of analyzing local land use combinations, we studied land cover mosaics at a meso-level of spatial scale and interpreted these in terms of human–environmental interactions. These landscape mosaics were then overlaid with population census data. Results showed that swidden agricultural landscapes, involving 17% of the population, dominate 29% of the country, while permanent agricultural landscapes involve 74% of the population in 29% of the territory. Forests still form an important component of these landscape mosaics

    Assessing regional farming system diversity using a mixed methods typology: the value of comparative agriculture tested in broadacre Australia

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    Most farm and farmer typologies focus on specific aspects and use standard structural and socio-economic indicators. Regional assessments of agricultural diversity based on farming systems are rarely done, as detailed and representative information is difficult to collect. The discipline of comparative agriculture addresses these challenges but remains little known, and seldom applied to broadacre situations. This study demonstrates in Western Australia the value of its mixed methods and multi-disciplinary concepts to determine the level and nature of regional farming system heterogeneity. The typology built comprised six farming systems based on 36 farms that represented half the farming population of a 4000 km 2 area (broadacre rainfed systems dominated by winter cereals and sheep, Mediterranean climate). The farm groups corresponding to these farming systems differed across 36 variables representing biophysical, technical, and social aspects at varied spatial and temporal scales. Results were compared with five sets of farm clusters produced through multivariate clustering procedures commonly employed to build typologies. These farm clusters differed across fewer variables than the farm groups of the comparative agriculture typology. The analytical, methodological and conceptual tools used in comparative agriculture to solve the challenges associated with the holistic study of farming system heterogeneity are discussed. These included basing data collection and analysis on an empirical approach that assessed groups of farms rather than individuals, solving data scarcity through a range of qualitative techniques, and progressively informing the choice of typology criteria. Comparative agriculture thus provides an alternative to standard typology paradigms that deserves wider application

    Culture du paysage, gouvernance territoriale et mise en tourisme dans des montagnes rurales de l&8217;Asie méridionale (Népal, Inde, Chine, Laos, Vietnam)

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    Five case studies are presented, all located in highland regions of South Asia and inhabited by ethnic minorities (India, Nepal, China, Laos, Vietnam), in order to analyze the consequences of narratives, actions and transformations of governance via the landscape. How does the landscape become, through tourism, a "way of seeing" territories, how does it foster renewed governance of these territories? After having shown how the use of landscape resources leads to the development of a landscape culture via tourism, we will see that the landscape occupies various places in the processes of territorial governance. A final typology will be based on three criteria : consciousness of the landscape, governance process, and tourism expansion
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