364 research outputs found

    Association between vitamin D deficiency and long hospital stay in geriatric acute care unit: results from a pilot cohort study

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    Finding a biomarker of long length-of-stay (LOS) would provide a simple solution to target frail older inpatients at such risk. The aim of this study was to determine whether serum 25-hydroxyvitamin D (25OHD) deficiency, defined as serum concentration <25 nmol/L, was associated with long LOS among inpatients admitted to a geriatric acute care unit. Three hundred and six older inpatients (mean age 84.6 +/- 6.4 years, 61.8 % women) were consecutively included in this longitudinal prospective cohort study. Patients were separated into two groups according to LOS tertiles: highest tertile (>= 14 days; n = 120) versus the other two tertiles combined (<14 days; n = 186). Serum 25OHD deficiency (58.3 vs. 38.7 %, P = 0.001) and the prevalence of male gender (58.3 vs. 28.5 %, P < 0.001) were higher among inpatients with the highest LOS compared with those with lower LOS. Serum 25OHD deficiency [odds ratio (OR) = 2.22, P = 0.001 for unadjusted model; OR = 1.87, P = 0.012 for fully adjusted model) and male gender (OR = 2.87, P < 0.001 for unadjusted model; OR = 2.64, P = 0.001 for full model) were associated with a high LOS. Vitamin D deficiency and male gender were risk factors for a long LOS in this pilot study. Using these risk factors to identify inpatients at risk of long LOS may be helpful in adapting early care plans, and thus improving inpatients\u27 health and shortening LOS

    Transport and cooling of singly-charged noble gas ion beams

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    The transport and cooling of noble gas singly-charged ion beams by means of a Radio Frequency Quadrupole Cooler Buncher (RFQCB) have been studied at the LIMBE low energy beam line of the GANIL facility. Ions as light as 4He+^{4}He^+ have been cooled and stored before their extraction in bunches using H2H_2 as buffer gas. Bunches characteristics have been studied as a function of the parameters of the device. Sizeable transmissions of up to 10 % have been obtained. A detailed study of the lifetime of ions inside the buncher has been performed giving an estimate of the charge exchange cross-section. Results of a microscopic Monte-Carlo transport code show reasonable agreement with experimental data.Comment: 13 figure

    Lifetimes of C-60(2-) and C-70(2-) dianions in a storage ring

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    C-60(2-) and C-70(2-) dianions have been produced by electrospray of the monoanions and subsequent electron pickup in a Na vapor cell. The dianions were stored in an electrostatic ring and their decay by electron emission was measured up to 1 s after injection. While C-70(2-) ions are stable on this time scale, except for a small fraction of the ions which have been excited by gas collisions, most of the C-60(2-) ions decay on a millisecond time scale, with a lifetime depending strongly on their internal temperature. The results can be modeled as decay by electron tunneling through a Coulomb barrier, mainly from thermally populated triplet states about 120 meV above a singlet ground state. At times longer than about 100 ms, the absorption of blackbody radiation plays an important role for the decay of initially cold ions. The tunneling rates obtained from the modeling, combined with WKB estimates of the barrier penetration, give a ground-state energy 200 +/- 30 meV above the energy of the monoanion plus a free electron and a ground-state lifetime of the order of 20 s. (c) 2006 American Institute of Physics

    GANIL operation status and upgrade of SPIRAL1

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    International audienceThe GANIL facility (Caen, France) is dedicated to the acceleration of heavy ion beams for nuclear physics, atomic physics, radiobiology and material irradiation. The production of stable and radioactive ion beams for nuclear physics studies represents the main part of the activity. The exotic beams are produced by the Isotope Separation On-Line method with SPIRAL1 facility. It is running since 2001, producing and post-accelerating radioactive ion beams. The review of the operation from 2001 to 2011 is presented. Because of the physicist demands, the facility is about to be improved with the project Upgrade SPIRAL1. The goal of the project is to extend the range of post-accelerated exotic beams available. The upgrade of the "Système de Production d'Ions Radioactifs en Ligne" phase I (SPIRAL1) is in progress and should be ready by 2015

    MONOBOB II : Latest results of monocharged ions source for SPIRAL2 project

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    Original publication available at http://www.jacow.orgInternational audienceAmong the sources which can be installed in the radioactive ion production module of SPIRAL II, a singly-charged ECRIS has been chosen to produce ions from gaseous elements. Its characterization is under way on a test bench at GANIL. Extraction, transport and response time results are presented

    Nuclear structure and reaction studies at SPIRAL

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    The SPIRAL facility at GANIL, operational since 2001, is described briefly. The diverse physics program using the re-accelerated (1.2 to 25 MeV/u) beams ranging from He to Kr and the instrumentation specially developed for their exploitation are presented. Results of these studies, using both direct and compound processes, addressing various questions related to the existence of exotic states of nuclear matter, evolution of new "magic numbers", tunnelling of exotic nuclei, neutron correlations, exotic pathways in astrophysical sites and characterization of the continuum are discussed. The future prospects for the facility and the path towards SPIRAL2, a next generation ISOL facility, are also briefly presented.Comment: 48 pages, 27 figures. Accepted for publication in Journal of Physics

    Production of multi-charged phosphorus ions with ecris 'SUPERSHyPIE' at GANIL

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    The Ganil's Ion Production Group tested the source SUPERSHyPIE123 for theproduction of phosphorus n+ ion beams. The SUPERSHyPIE ecris is used for many testsof multi-charged ion production and supply ion beams for LIMBE4 (low energie beamline). This ion source works with a 14.5ghz RF power injected by a circular waveguide inthe axis of the sourc

    Primary processes: from atoms to diatomic molecules and clusters

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    International audienceThis article presents a short review of the main progresses achieved at the GANIL facilities during the last thirty years in the field of ion-atom and ion-diatomic molecule collisions. Thanks to the wide range of projectile energies and species available on the different beam lines of the facility, elementary processes such as electron capture, ionization and excitation have been extensively studied. Beside primary collision mechanisms, the relaxation processes of the collision partners after the collision have been another specific source of interest. Progresses on other fundamental processes such as Young type interferences induced by ion-molecule collisions or shake off ionization resulting from nuclear beta decay are also presented. 1. Introduction For the electronic structures of atoms and molecules, precise theoretical knowledge and high-resolution experimental data are available. But the complete understanding of dynamic processes in atomic collisions remains a challenge, due to large theoretical problems in describing time-dependent many-particle reactions, and to experimental difficulties in performing complete experiments in which all relevant quantities are accessible. Elementary collisions involving ions, atoms and molecules play an important role in many gaseous and plasma environments, where they provide both the heating and cooling mechanisms. The study of such collisions is thus not only of fundamental importance, it is also essential for the understanding of large-scale systems such as astrophysical plasmas, planetary atmospheres, gas discharge lasers, semiconductor processing plasmas, and fusion plasmas. Collisions between ions and atoms (or simple molecules) give also access to the elementary processes responsible for energy transfer in ion-matter and ion-biological molecule collisions. Complete knowledge of these elementary processes is thus of primordial importance for ion induced modification of materials as well as for radiolysis, radiotherapy and biological damages due to radiation exposure
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