518 research outputs found

    Magnetic properties of (Fe1x_{1-x}Cox_x)2_2B alloys and the effect of doping by 5dd elements

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    We have explored, computationally and experimentally, the magnetic properties of \fecob{} alloys. Calculations provide a good agreement with experiment in terms of the saturation magnetization and the magnetocrystalline anisotropy energy with some difficulty in describing Co2_2B, for which it is found that both full potential effects and electron correlations treated within dynamical mean field theory are of importance for a correct description. The material exhibits a uniaxial magnetic anisotropy for a range of cobalt concentrations between x=0.1x=0.1 and x=0.5x=0.5. A simple model for the temperature dependence of magnetic anisotropy suggests that the complicated non-monotonous temperature behaviour is mainly due to variations in the band structure as the exchange splitting is reduced by temperature. Using density functional theory based calculations we have explored the effect of substitutional doping the transition metal sublattice by the whole range of 5dd transition metals and found that doping by Re or W elements should significantly enhance the magnetocrystalline anisotropy energy. Experimentally, W doping did not succeed in enhancing the magnetic anisotropy due to formation of other phases. On the other hand, doping by Ir and Re was successful and resulted in magnetic anisotropies that are in agreement with theoretical predictions. In particular, doping by 2.5~at.\% of Re on the Fe/Co site shows a magnetocrystalline anisotropy energy which is increased by 50\% compared to its parent (Fe0.7_{0.7}Co0.3_{0.3})2_2B compound, making this system interesting, for example, in the context of permanent magnet replacement materials or in other areas where a large magnetic anisotropy is of importance.Comment: 15 pages 17 figure

    Indicators for Women's Health in Developing Countries: What They Reveal and Conceal

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    Summary The health of women has recently resurfaced in the health policy debate and has tended to become viewed as important primarily because of its contribution to infant health. Maternal deaths are characterised by a range of fairly typical causes, all of which can normally be prevented with good obstetric medical services and antenatal care. The most widely used indicator, the maternal mortality rare, is closely associated with a range of socioeconomic determinants; most notably poverty and access to obstetric services, which suggests that medicine alone cannot solve the whole problem. Factors such as urbanization, female secondary education, contraceptive prevalence and fertility all appear to be important intermediate determinants, which highlight the fact that the problem is really rooted in a much wider one of the status and role of women in development. The indicator of the maternal mortality rate itself actually underestimates the true impact of fertility on women's health. The indicator of lifetime risk (of dying in childbirth) is much more relevant and it provides an even starker picture of differentials in health risks, and the role fertility plays in these risks. It puts fertility back into women's health and the object of measurement is women's lives rather than the disembodied event of birth. Resumé Indicateurs de la santé des femmes dans les pays en voie de développement: ce qu'ils révèlent et ce qu'ils cachent Le sujet de la santé des femmes remonte à la surface dans le débat concernant les politiques de santé; ce sujet a été censé important, du moins récemment, en raison principalement de sa contribution à la santé infantile. Les décès maternels sont caractérisés par une gamme de causes relativement typiques et qu'il est normalement possible d'éviter moyennant une bonne obstétrique médicale et des soins adéquats en période prénatale. L'indicateur le plus fréquemment employé, le taux de mortalité maternel, est étroitement lié à une gamme de déterminants socio?économiques, notamment la pauvreté et l'accès aux services obstétriques, qui suggèrent que l'accès à la médecine seule ne peut entièrement résoudre le problème. Les facteurs tels que l'urbanisation, l'enseignement secondaire des femmes, la disponibilité de la contraception et la fécondité sembleraient tous être des indicateurs d'ordre intermédiaire, et ceci aurait tendance à souligner le fait que le problème véritable est effectivement encastré dans un problème encore plus grave, à savoir celui du rôle et de la situation des femmes dans le développement. L'indicateur de mortalité maternelle sous?estime en fait l'impact véritable de la fertilité sur la santé des femmes. L'indicateur de risque à longueur de vie (de mourir durant un accouchement) est beaucoup plus approprié et offre une image encore plus déprimante des différentiels dans les risques à la santé, et du rôle que la fertilité joue dans ces risques. Cet indicateur remet en cause la fertilité au sein de la santé des femmes et en fait une mesure de la vie des femmes, à la place du simple événement qu'est tel ou tel accouchement. Resumen Indicadores de salud femenina en los países en desarrollo: lo que revelan y lo que ocultan El tema de la salud de la mujer ha resurgido recientemente en el debate sobre directivas de salud, y la tendencia ha sido considerarlo importante primordialmente por su contribución a la salud infantil. Las muertes maternales tienen una serie de causas bastante típicas, todas las cuales pueden normalmente ser evitadas con buenos servicios obstétricos y cuidados prenatales. El indicator más usado, la tasa de mortalidad maternal, está asociado a los determinantes socioeconómicos, notablemente la pobreza y la falta de acceso a los servicios ginecológicos, lo que sugiere que la medicina no puede resolver todo el problema por sí sola. Factores como la urbanización, la educación secundaria femenina, la prevalencia anticonceptiva y la fertilidad parecen ser importantes determinantes intermedios, y eso destaca el hecho de que el problema está realmente enraizado en otro mucho mas amplio: la condición y el papel de la mujer en el desarrollo. El indicador de la tasa de mortalidad maternal en realidad subestima el verdadero impacto de la fertilidad en la salud femenina. El indicador de riesgo vital: muerte de parto es mucho más significativo y da una imagen aún más severa de los diferenciales en riesgos de salud y el papel jugado por la fertilidad en esos riesgos. Pone a la fertilidad dentro de la salud femenina nuevamente, y lo que se mide es la vida de la mujer en vez del evento aislado del parto

    Effects of surface vibrations on interlayer mass-transport: ab initio molecular dynamics investigation of Ti adatom descent pathways and rates from TiN/TiN(001) islands

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    We carry out density-functional ab initio molecular dynamics (AIMD) simulations of Ti adatom (Tiad) migration on, and descent from, TiN -faceted epitaxial islands on TiN(001) at temperatures T ranging from 1200 to 2400 K. Adatom-descent energy-barriers determined via ab initio nudged-elastic-band calculations at 0 Kelvin suggest that Ti interlayer transport on TiN(001) occurs essentially exclusively via direct hopping onto a lower layer. However, AIMD simulations reveal comparable rates for Tiad descent via direct-hopping vs. push-out/exchange with a Ti island edge atom for T >= 1500 K. We demonstrate that the effect is due to surface vibrations, which yield considerably lower activation energies at finite temperatures by significantly modifying the adatom push/out-exchange reaction pathway.Comment: 13 Figure

    Reframing Gender Justice in an Unequal, Volatile World: IDS’ Directions for Future Research on Gender and Sexuality in Development

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    At a time of major changes in global politics and trends, and major shifts in international development following the establishment of the global Sustainable Development Goals in Agenda 2030, the Gender and Sexuality cluster at the Institute of Development Studies engaged in collaborative discussions and consultations over nine months with partner organisations, networks, external experts and policymakers. Following this process through most of 2016, this brief outlines our priority directions for future research on gender and sexuality in development in an increasingly unequal, polarised and volatile world.UK Department for International Developmen

    Rechargeable Batteries of the Future—The State of the Art from a BATTERY 2030+ Perspective

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    The development of new batteries has historically been achieved through discovery and development cycles based on the intuition of the researcher, followed by experimental trial and error—often helped along by serendipitous breakthroughs. Meanwhile, it is evident that new strategies are needed to master the ever-growing complexity in the development of battery systems, and to fast-track the transfer of findings from the laboratory into commercially viable products. This review gives an overview over the future needs and the current state-of-the art of five research pillars of the European Large-Scale Research Initiative BATTERY 2030+, namely 1) Battery Interface Genome in combination with a Materials Acceleration Platform (BIG-MAP), progress toward the development of 2) self-healing battery materials, and methods for operando, 3) sensing to monitor battery health. These subjects are complemented by an overview over current and up-coming strategies to optimize 4) manufacturability of batteries and efforts toward development of a circular battery economy through implementation of 5) recyclability aspects in the design of the battery

    Developing a European longitudinal and interprofessional curriculum for clinical reasoning

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    Clinical reasoning is a complex and crucial ability health professions students need to acquire during their education. Despite its importance, explicit clinical reasoning teaching is not yet implemented in most health professions educational programs. Therefore, we carried out an international and interprofessional project to plan and develop a clinical reasoning curriculum with a train-the-trainer course to support educators in teaching this curriculum to students. We developed a framework and curricular blueprint. Then we created 25 student and 7 train-the-trainer learning units and we piloted 11 of these learning units at our institutions. Learners and faculty reported high satisfaction and they also provided helpful suggestions for improvements. One of the main challenges we faced was the heterogeneous understanding of clinical reasoning within and across professions. However, we learned from each other while discussing these different views and perspectives on clinical reasoning and were able to come to a shared understanding as the basis for developing the curriculum. Our curriculum fills an important gap in the availability of explicit clinical reasoning educational materials both for students and faculty and is unique with having specialists from different countries, schools, and professions. Faculty time and time for teaching clinical reasoning in existing curricula remain important barriers for implementation of clinical reasoning teaching

    β-Microseminoprotein Endows Post Coital Seminal Plasma with Potent Candidacidal Activity by a Calcium- and pH-Dependent Mechanism

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    The innate immune factors controlling Candida albicans are mostly unknown. Vulvovaginal candidiasis is common in women and affects approximately 70–75% of all women at least once. Despite the propensity of Candida to colonize the vagina, transmission of Candida albicans following sexual intercourse is very rare. This prompted us to investigate whether the post coital vaginal milieu contained factors active against C. albicans. By CFU assays, we found prominent candidacidal activity of post coital seminal plasma at both neutral and the acid vaginal pH. In contrast, normal seminal plasma did not display candidacidal activity prior to acidification. By antifungal gel overlay assay, one clearing zone corresponding to a protein band was found in both post coital and normal seminal plasma, which was subsequently identified as β-microseminoprotein. At neutral pH, the fungicidal activity of β-microseminoprotein and seminal plasma was inhibited by calcium. By NMR spectroscopy, amino acid residue E71 was shown to be critical for the calcium coordination. The acidic vaginal milieu unleashed the fungicidal activity by decreasing the inhibitory effect of calcium. The candidacidal activity of β-microseminoprotein was mapped to a fragment of the C-terminal domain with no structural similarity to other known proteins. A homologous fragment from porcine β-microseminoprotein demonstrated calcium-dependent fungicidal activity in a CFU assay, suggesting this may be a common feature for members of the β-microseminoprotein family. By electron microscopy, β-microseminoprotein was found to cause lysis of Candida. Liposome experiments demonstrated that β-microseminoprotein was active towards ergosterol-containing liposomes that mimic fungal membranes, offering an explanation for the selectivity against fungi. These data identify β-microseminoprotein as an important innate immune factor active against C. albicans and may help explain the low sexual transmission rate of Candida

    Toward Rare-Earth-Free Permanent Magnets: A Combinatorial Approach Exploiting the Possibilities of Modeling, Shape Anisotropy in Elongated Nanoparticles, and Combinatorial Thin-Film Approach

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    The objective of the rare-earth free permanent magnets (REFREEPM) project is to develop a new generation of high-performance permanent magnets (PMs) without rare earths. Our approach is based on modeling using a combinatorial approach together with micromagnetic modeling and the realization of the modeled systems (I) by using a novel production of high-aspect-ratio (>5) nanostructrures (nanowires, nanorods, and nanoflakes) by exploiting the magnetic shape anisotropy of the constituents that can be produced via chemical nanosynthesis polyol process or electrodeposition, which can be consolidated with novel processes for a new generation of rare-earth free PMs with energy product in the range of 60 kJ/m3 < (BH)max < 160 kJ/m3 at room temperature, and (II) by using a high-throughput thin-film synthesis and high-throughput characterization approach to identify promising candidate materials that can be stabilized in a tetragonal or hexagonal structure by epitaxial growth on selected substrates, under various conditions of pressure, stoichiometry, and temperature. In this article, we report the progress so far in selected phases.This work is supported by European Commission (REFREEPERMAG project) grant number GA-NMP3-SL-2012-280670
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