265 research outputs found

    Dislocation core field. I. Modeling in anisotropic linear elasticity theory

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    Aside from the Volterra field, dislocations create a core field, which can be modeled in linear anisotropic elasticity theory with force and dislocation dipoles. We derive an expression of the elastic energy of a dislocation taking full account of its core field and show that no cross term exists between the Volterra and the core fields. We also obtain the contribution of the core field to the dislocation interaction energy with an external stress, thus showing that dislocation can interact with a pressure. The additional force that derives from this core field contribution is proportional to the gradient of the applied stress. Such a supplementary force on dislocations may be important in high stress gradient regions, such as close to a crack tip or in a dislocation pile-up

    Direct identification of extended defects as vortex pinning centers in melt textured YBa2Cu3O7-Y2BaCuO5 composites

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    Single domain YBa2Cu3O7-Y2BaCuO5 melt textured ceramic composites have revealed a very rich microstructure, which has usually impeded, by using standard measurements, to evaluate the contribution of each defect to the enhancement of the critical current. We have measured the inplane magnetoresistance anisotropy and the anisotropic in-plane inductive critical currents and we show that together with the microstructural TEM analysis, the contribution of the different extended pinning centers can be separated. These results have allowed us to infer the kind of microstructure modifications required to improve the critical current. In particular, we present an isostatic pressing deformation technique as a very promising post-processing treatment to strongly increase the critical currents of these composites.Peer Reviewe

    Comparison between classical potentials and ab initio for silicon under large shear

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    The homogeneous shear of the {111} planes along the direction of bulk silicon has been investigated using ab initio techniques, to better understand the strain properties of both shuffle and glide set planes. Similar calculations have been done with three empirical potentials, Stillinger-Weber, Tersoff and EDIP, in order to find the one giving the best results under large shear strains. The generalized stacking fault energies have also been calculated with these potentials to complement this study. It turns out that the Stillinger-Weber potential better reproduces the ab initio results, for the smoothness and the amplitude of the energy variation as well as the localization of shear in the shuffle set

    Calcitization of aragonitic bryozoans in Cenozoic tropical carbonates from East Kalimantan, Indonesia

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    © The Author(s) 2016. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The file attached is the published version of the article

    Patterns of medication errors involving pediatric population reported to the French Medication Error Guichet

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    Background: Medication error is a global threat to patient safety, particularly in pediatrics. Yet, this issue remains understudied in this population, in both hospital and community settings. Objectives: To characterize medication errors involving pediatrics reported to the French Medication Error Guichet, and compare them with medication errors in adults, in each of the hospital and community settings. Methods: This was a retrospective secondary data analysis of medication errors reported throughout 2013-2017. Descriptive and multivariate analyses were performed to compare actual and potential medication error reports between pediatrics (aged 18 and <60 years). Two subanalyses of actual medication errors with adverse drug reaction (ADR), and serious ADR were conducted. Results: We analyzed 4,718 medication error reports. In pediatrics, both in hospital (n=791) and community (n=1,541) settings, antibacterials for systemic use (n=121, 15.7%; n=157, 10.4%, respectively) and wrong dose error type (n=391, 49.6%; n=549, 35.7%, respectively) were frequently reported in medication errors. These characteristics were also significantly more likely to be associated with reported errors in pediatrics compared with adults. In the hospital setting, analgesics (adjusted odds ratio (aOR)=1.59; 95% confidence interval (CI) 1.03:2.45), and blood substitutes and perfusion solutions (aOR=3.74; 95%CI 2.24:6.25) were more likely to be associated with reported medication errors in pediatrics; the latter drug class (aOR=3.02; 95%CI 1.59:5.72) along with wrong technique (aOR=2.28; 95%CI 1.01:5.19) and wrong route (aOR=2.74; 95%CI 1.22:6.15) error types related more to reported medication errors with serious ADR in pediatrics. In the community setting, the most frequently reported pediatric medication errors involved vaccines (n=389, 25.7%). Psycholeptics (aOR=2.42; 95%CI 1.36:4.31) were more likely to be associated with reported medication errors with serious ADR in pediatrics. Wrong technique error type (aOR=2.71; 95%CI 1.47:5.00) related more to reported medication errors with ADR in pediatrics. Conclusions: We identified pediatric-specific medication error patterns in the hospital and community settings. Our findings inform focused error prevention measures, and pave the way for interventional research targeting the needs of this population

    Site testing for submillimetre astronomy at Dome C, Antarctica

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    Over the past few years a major effort has been put into the exploration of potential sites for the deployment of submillimetre astronomical facilities. Amongst the most important sites are Dome C and Dome A on the Antarctic Plateau, and the Chajnantor area in Chile. In this context, we report on measurements of the sky opacity at 200 um over a period of three years at the French-Italian station, Concordia, at Dome C, Antarctica. We also present some solutions to the challenges of operating in the harsh polar environ- ment. Dome C offers exceptional conditions in terms of absolute atmospheric transmission and stability for submillimetre astron- omy. Over the austral winter the PWV exhibits long periods during which it is stable and at a very low level (0.1 to 0.3 mm). Higher values (0.2 to 0.8 mm) of PWV are observed during the short summer period. Based on observations over three years, a transmission of around 50% at 350 um is achieved for 75% of the time. The 200-um window opens with a typical transmission of 10% to 15% for 25% of the time. Dome C is one of the best accessible sites on Earth for submillimetre astronomy. Observations at 350 or 450 {\mu}m are possible all year round, and the 200-um window opens long enough and with a sufficient transparency to be useful. Although the polar environment severely constrains hardware design, a permanent observatory with appropriate technical capabilities is feasible. Because of the very good astronomical conditions, high angular resolution and time series (multi-year) observations at Dome C with a medium size single dish telescope would enable unique studies to be conducted, some of which are not otherwise feasible even from space

    e-Pilly TROP Maladies infectieuses tropicales

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    L’e-Pilly TROP est un ouvrage d’infectiologie tropicale destinĂ© aux mĂ©decins et aux Ă©tudiants en mĂ©decine des pays francophones du Sud. La prise en compte des diffĂ©rents niveaux de la pyramide sanitaire dans ces pays le rend aussi accessible aux infirmiers des centres de santĂ© communautaires urbains et des structures de santĂ© intermĂ©diaires des zones rurales. Par dĂ©finition, les Pays En DĂ©veloppement accroissant progressivement leurs capacitĂ©s de diagnostic biologique et de traitement, les outils de prise en charge correspondent aux moyens des niveaux pĂ©riphĂ©riques comme Ă  ceux des niveaux hospitaliers de rĂ©fĂ©rence
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