3,768 research outputs found

    Dendrochronological approach to the radial growth of okoume (Congo)

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    La croissance radiale de 4 sections d'okoumé du Congo provenant de 4 arbres différents est analysée. La présence dans la région d'au moins une saison sèche marquée permet de définir des cernes de croissance annuels. Ils sont mesurés et les courbes des largeurs de cernes sont confrontées de manière graphique afin de vérifier que l'année de formation attribuée à chaque cerne est exacte (interdatation). Le synchronisme est mauvais lorsque les courbes appartiennent à des arbres différents. Pour lever le doute quant à la validité de la délimitation des cernes annuels, une confrontation avec les enregistrements pluviométriques de Pointe Noire est tentée. Le résultat du test est positif et les limites de cernes établies au début de l'étude sont maintenues. L'approche dendrochronologique sur une espèce telle que l'okoumé est donc possible mais une vérification de l'interdatation par confrontation avec des données climatologiuqes est indispensable. Ce type d'approche conduisant à une datation absolue des cernes peut être d'un grand intérêt en écologie tropicale : elle permet en particulier de replacer les analyses biogéochimiques des cernes dans un cadre chronologique exact, ou encore d'apprécier la vitesse de progression des lisières forestières. (Résumé d'auteur

    Bohr's complementarity relation and the violation of the CP symmetry in high energy physics

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    We test Bohr's complementary relation, which captures the most counterintuitive difference of a classical and a quantum world, for single and bipartite neutral kaons. They present a system that is naturally interfering, oscillating and decaying. Moreover, kaons break the CP symmetry (C...charge conjugation, P...parity). In detail we discuss the effect of the CP violation on Bohr's relation, i.e. the effect on the "particle-like" information and the "wave-like" information. Further we show that the quantity that complements the single partite information for bipartite kaons is indeed concurrence, a measure of entanglement, strengthening our concept of entanglement. We find that the defined entanglement measure is independent of CP violation while it has been shown that nonlocality is sensitive to CP violation.Comment: 8 pages, 2 figure

    Troubles musculo-squelettiques : rôles des médecins-conseils et relations interprofessionnelles

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    INTRODUCTION: Musculoskeletal disorders (MSD) were responsible for 9.7 million days of sick leave in 2010 in France. They are also a leading cause of occupational exclusion. The objective was to study the role of medical advisers (Mas) in the care of patients with MSD and their interactions with general practitioners (GPs) and occupational health physicians (OPs). METHODS: We performed a qualitative study with semi-structured interviews with medical advisers from the Brittany region. Semistructured interviews were double-coded and were submitted to thematic analysis. RESULTS: Nine interviews were conducted with MAs from the general regime, agricultural regime, and independent workers regime. MAs described an increase in MSD, especially with complex forms. They explained that their activity was not limited to control, but that they also had an important role in limiting occupational exclusion. It is important to anticipate difficulties related to return to work in this setting. They reported contrasted but necessary relations with GPs who are at the centre of care. Return to work may require negotiation with OPs. CONCLUSION: Relations between MAs and GPs are partly based on control of prescriptions, which can create a climate of suspicion. Emphasizing the fight against occupational exclusion can provide new light on the role of MAs. Improving relations between MAs and GPs can be achieved by a better understanding of their respective roles

    Entanglement of Dirac fields in non-inertial frames

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    We analyze the entanglement between two modes of a free Dirac field as seen by two relatively accelerated parties. The entanglement is degraded by the Unruh effect and asymptotically reaches a non-vanishing minimum value in the infinite acceleration limit. This means that the state always remains entangled to a degree and can be used in quantum information tasks, such as teleportation, between parties in relative uniform acceleration. We analyze our results from the point of view afforded by the phenomenon of entanglement sharing and in terms of recent results in the area of multi-qubit complementarity.Comment: 15 pages, with 8 figures (Mar 2006); accepted to Physical Review A, July 2006 - slightly revise

    Theory and simulation of short-range models of globular protein solutions

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    We report theoretical and simulation studies of phase coexistence in model globular protein solutions, based on short-range, central, pair potential representations of the interaction among macro-particles. After reviewing our previous investigations of hard-core Yukawa and generalised Lennard-Jones potentials, we report more recent results obtained within a DLVO-like description of lysozyme solutions in water and added salt. We show that a one-parameter fit of this model based on Static Light Scattering and Self-Interaction Chromatography data in the dilute protein regime, yields demixing and crystallization curves in good agreement with experimental protein-rich/protein-poor and solubility envelopes. The dependence of cloud and solubility points temperature of the model on the ionic strength is also investigated. Our findings highlight the minimal assumptions on the properties of the microscopic interaction sufficient for a satisfactory reproduction of the phase diagram topology of globular protein solutions.Comment: 17 pages, 8 figures, Proc. of Conference "Structural Arrest Transitions in Colloidal Systems with Short-Range Attractions", Messina (ITALY) 17-20 December 200

    Multifaceted intervention to decrease the rate of severe postpartum haemorrhage: the PITHAGORE6 cluster-randomised controlled trial.: Intervention to decrease severe postpartum haemorrhage

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    International audienceOBJECTIVE: Decreasing the prevalence of severe postpartum haemorrhages (PPH) is a major obstetrical challenge. These are often considered to be associated with substandard initial care. Strategies to increase the appropriateness of early management of PPH must be assessed. We tested the hypothesis that a multifaceted intervention aimed at increasing the translation into practice of a protocol for early management of PPH, would reduce the incidence of severe PPH. DESIGN: Cluster-randomised trial. POPULATION: 106 maternity units in six French regions. METHODS: Maternity units were randomly assigned to receive the intervention, or to have the protocol passively disseminated. The intervention combined outreach visits to discuss the protocol in each local context, reminders, and peer reviews of severe incidents, and was implemented in each maternity hospital by a team pairing an obstetrician and a midwife. MAIN OUTCOME MEASURES: The primary outcome was the incidence of severe PPH, defined as a composite of one or more of: transfusion, embolisation, surgical procedure, transfer to intensive care, peripartum haemoglobin decrease of 4 g/dl or more, death. The main secondary outcomes were PPH management practices. RESULTS: The mean rate of severe PPH was 1.64% (SD 0.80) in the intervention units and 1.65% (SD 0.96) in control units; difference not significant. Some elements of PPH management were applied more frequently in intervention units-help from senior staff (P = 0.005), or tended to - second-line pharmacological treatment (P = 0.06), timely blood test (P = 0.09). CONCLUSION: This educational intervention did not affect the rate of severe PPH as compared with control units, although it improved some practices
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