1,089 research outputs found

    Utilisation d'ions lithium pour l'analyse des surfaces et des couches minces

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    Dans la tendance actuelle à utiliser des ions plus lourds que les particules α en rétrodiffusion élastique (domaine d'énergie de l'ordre du MeV), l'emploi d'ions lithium apparaît constituer une amélioration notable des caractéristiques essentielles de la méthode. Ceci est particulièrement vrai en ce qui concerne la résolution en profondeur, avec le maintien de la résolution des détecteurs, pour ce type d'ions. Nous présentons ici, en même temps qu'une étude comparative des performances analytiques des ions Li et d'autres particules, quelques applications en montrant l'intérêt dans l'étude des surfaces et des couches minces. Parmi les applications les plus caractéristiques, citons, pour des échantillons épais, l'étude simultanée de la composition des couches d'oxydation anodique formées à la surface d'aluminium et du comportement de l'impureté majeure du bain de formation. Dans les études de couches minces, outre la détermination précise de la stoechiométrie des couches diélectriques AlN, SiO, Al2O3, des effets d'implantation pourront être étudiés, comme l'oxygène dans les couches SiO

    Possible fabrication techniques and welding specifications for the external cylinder of the CMS coil

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    The Compact Muon Solenoid (CMS) is one of the experiments, which are being designed in the framework of the Large Hadron Collider (LHC) project at CERN. The design field of the CMS magnet is 4 T, the magnetic length is 12.5 m and the free aperture is 6 m in diameter. This is achieved with a 4 layer and 5 module superconducting Al- stabilized coil energized at a nominal current of 20 kA at 4.5 K. In the CMS coil the structural function is ensured, unlike in other existing Al-stabilized thin solenoids, both by the Al-alloy reinforced conductor and the external cylinder. The calculated stress level in the cylinder at operating conditions is particularly severe. In this paper the different possible fabrication techniques are assessed and compared and a possible welding specification for this component is given. (9 refs)

    Pharmacological therapies in post stroke recovery: Recommendations for future clinical trials

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    Stroke is a leading cause of serious long-term disability in adults and is the second leading cause of death worldwide. Early reperfusion and neuroprotection techniques have been the focus of much effort with the aim of very acute treatment of the stroke. Targeting different mechanisms, pharmacological therapies have the potential to reduce disability in a large fraction of patients who survive the acute stroke. The brain's capacity to reorganize after stroke through plasticity mechanisms can be modulated by pharmacological agents. A number of therapeutic interventions are under study, including small molecules, growth factors, and monoclonal antibodies. Recently it has been shown that the SSRI fluoxetine improved motor deficit in patients with ischaemic stroke and hemiplegia which appeared to be independent of the presence of depression. In this context, it is of major importance to support innovative research in order to promote the emergence of new pharmacological treatments targeting neurological recovery after stroke, as opposed to acute de-occlusion and neuroprotection. This paper is the work of a group of 14 scientists with aim of (1) addressing key areas of the basic and clinical aspects of human brain plasticity after stroke and potential pharmacological targets for recovery, (2) asking questions about the most appropriate characteristics of clinical trials testing drugs in post stroke recovery and (3) proposing recommendations for future clinical trials. © 2013 Springer-Verlag Berlin Heidelberg

    Intervention and revision: Expertise and interaction in text mediation

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    Many EAL (English as an Additional Language) scholars enlist text mediators’ support when faced with the challenges of writing for international publication. However, the contributions these individuals are able to make in improving scientific manuscripts remains unclear, especially when language professionals such as English teachers do this work. In this article, we explore this topic by examining how three mediators employed their very different expertise and brought different processes to bear on the same discussion section of a medical manuscript written by a novice scholar in China. We find that successfully mediated texts are often the result of an interplay between the mediator’s expertise and the relationship between the participants. Our findings contradict those of previous studies that question the role of English teachers in this process and have the potential to inform both text mediation practices and revision studies

    The CMS conductor

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    The Compact Muon Solenoid (CMS) is one of the experiments, which are being designed in the framework of the Large Hadron Collider (LHC) project at CERN, the design field of the CMS magnet is 4 T, the magnetic length is 13 m and the aperture is 6 m. This high magnetic field is achieved by means of a 4 layer, 5 modules superconducting coil. The coil is wound from an Al-stabilized Rutherford type conductor. The nominal current of the magnet is 20 kA at 4.5 K. In the CMS coil the structural function is ensured, unlike in other existing Al-stabilized thin solenoids, both by the Al-alloy reinforced conductor and the external former. In this paper the retained manufacturing process of the 50-km long reinforced conductor is described. In general the Rutherford type cable is surrounded by high purity aluminium in a continuous co-extrusion process to produce the Insert. Thereafter the reinforcement is joined by Electron Beam Welding to the pure Al of the insert, before being machined to the final dimensions. During the manufacture the bond quality between the Rutherford cable and the high purity aluminium as well as the quality of the EB welding are continuously controlled by a novel ultrasonic phased array system. The dimensions of the insert and the final conductor are measured by laser micrometer. (8 refs)

    Imaging Oxygen Distribution in Marine Sediments. The Importance of Bioturbation and Sediment Heterogeneity

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    The influence of sediment oxygen heterogeneity, due to bioturbation, on diffusive oxygen flux was investigated. Laboratory experiments were carried out with 3 macrobenthic species presenting different bioturbation behaviour patterns:the polychaetes Nereis diversicolor and Nereis virens, both constructing ventilated galleries in the sediment column, and the gastropod Cyclope neritea, a burrowing species which does not build any structure. Oxygen two-dimensional distribution in sediments was quantified by means of the optical planar optode technique. Diffusive oxygen fluxes (mean and integrated) and a variability index were calculated on the captured oxygen images. All species increased sediment oxygen heterogeneity compared to the controls without animals. This was particularly noticeable with the polychaetes because of the construction of more or less complex burrows. Integrated diffusive oxygen flux increased with oxygen heterogeneity due to the production of interface available for solute exchanges between overlying water and sediments. This work shows that sediment heterogeneity is an important feature of the control of oxygen exchanges at the sediment–water interface

    The use of positive behaviour support plans in mental health inpatient care: a mixed methods study

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    An international drive is to minimise restrictive practices in mental healthcare. Positive behaviour support Plans (PBSPs) help staff prevent behaviour which would require restrictive intervention. Originating in learning disability services, data within mental healthcare are limited. To evaluate PBSPs within a mental health‐inpatient service; understand mental health nurses’ and relatives’ attitudes to them and understand the barriers and facilitators for their use in routine mental healthcare. Mixed methods ‐ quality‐ratings and interviews with relatives and nurses. PBSPs were poorly implemented. Relatives and nurses valued the potential of PBSPs to facilitate holistic care, though no relative had contributed to one and not every eligible patient had one. Barriers to their use included confusion around positive behaviour support, including how, when and for whom PBSPs should be used, and difficulties describing the function of a behaviour. The potential of PBSPs to improve mental healthcare is recognised. However, there are barriers to their use which should be addressed to ensure that PBSPs have been properly implemented before their impact on patient care can be assessed. Mental health professionals implementing PBSPs should engage with relatives and patients, gain organizational commitment and ensure that those involved understand fully the positive behaviour support approach
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