1,207 research outputs found

    The KATRIN Pre-Spectrometer at reduced Filter Energy

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    The KArlsruhe TRItium Neutrino experiment, KATRIN, will determine the mass of the electron neutrino with a sensitivity of 0.2 eV (90% C.L.) via a measurement of the beta-spectrum of gaseous tritium near its endpoint of E_0 =18.57 keV. An ultra-low background of about b = 10 mHz is among the requirements to reach this sensitivity. In the KATRIN main beam-line two spectrometers of MAC-E filter type are used in a tandem configuration. This setup, however, produces a Penning trap which could lead to increased background. We have performed test measurements showing that the filter energy of the pre-spectrometer can be reduced by several keV in order to diminish this trap. These measurements were analyzed with the help of a complex computer simulation, modeling multiple electron reflections both from the detector and the photoelectric electron source used in our test setup.Comment: 22 pages, 12 figure

    The leadership component of Kelly’s Mobilisation Theory : contribution, tensions, limitations and further development

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    This reassessment of Kelly’s analysis of the relationship of activist leadership to collective action within the overall jigsaw of mobilisation theory draws on social movement literature, studies by industrial relations scholars utilising aspects of Kelly’s approach – including this author’s own work – and related research on union leadership within collective mobilisation. In the process, it identifies and celebrates how Kelly’s work, whilst contributing a distinct and substantive actor-related approach, recognised that leadership is one ingredient amongst other factors, including important structural opportunities and constraints. It considers three potential ambiguities/tensions within Kelly’s conceptualisation of leadership related to the social construction of workers’ interests, spontaneity of workers’ action and the ‘leader/follower’ interplay. The review also identifies two important limitations, related to the union member/bureaucracy dynamic and the role of left-wing political leadership, and concludes by signalling different forms of leadership relationships on which further refinement and development would be fruitful

    Contested resources: unions, employers, and the adoption of new work practices in US and UK telecommunications

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    The pattern of adoption of high-performance work practices has been explained in terms of strategic contingency and in terms of union presence. We compare the post-deregulation/privatization changes in work practice at AT&T, Bell Atlantic and British Telecom. On the basis of these cases, we argue that the choice of new work practices should be understood as a consequence not only of the company's resources or changes in its environment, nor of a simple union presence, but also as a consequence of the practices' effects on union power, the nature of the union's engagement, and the union's strategic choices

    Spatial patterning of soil microbial communities created by fungus‐farming termites

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    Spatially overdispersed mounds of fungus‐farming termites (Macrotermitinae) are hotspots of nutrient availability and primary productivity in tropical savannas, creating spatial heterogeneity in communities and ecosystem functions. These termites influence the local availability of nutrients in part by redistributing nutrients across the landscape, but the links between termite ecosystem engineering and the soil microbes that are the metabolic agents of nutrient cycling are little understood. We used DNA metabarcoding of soils from Odontotermes montanus mounds to examine the influence of termites on soil microbial communities in a semi‐arid Kenyan savanna. We found that bacterial and fungal communities were compositionally distinct in termite‐mound topsoils relative to the surrounding savanna, and that bacterial communities were more diverse on mounds. The higher microbial alpha and beta diversity associated with mounds created striking spatial patterning in microbial community composition, and boosted landscape‐scale microbial richness and diversity. Selected enzyme assays revealed consistent differences in potential enzymatic activity, suggesting links between termite‐induced heterogeneity in microbial community composition and the spatial distribution of ecosystem functions. We conducted a large‐scale field experiment in which we attempted to simulate termites’ effects on microbes by fertilizing mound‐sized patches; this altered both bacterial and fungal communities, but in a different way than natural mounds. Elevated levels of inorganic nitrogen, phosphorus and potassium may help to explain the distinctive fungal communities in termite‐mound soils, but cannot account for the distinctive bacterial communities associated with mounds

    Beyond Teenage and Young Adult Cancer Care: Care Experiences of Patients Aged 25-39 Years Old in the UK National Health Service.

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    AimsAdolescents and young adults aged 15-39 years with cancer face unique medical, practical and psychosocial issues. In the UK, principal treatment centres and programmes have been designed to care for teenage and young adult patients aged 13-24 years in an age-appropriate manner. However, for young adults (YAs) aged 25-39 years with cancer, little access to age-specific support is available. The aim of this study was to examine this possible gap by qualitatively exploring YA care experiences, involving patients as research partners in the analysis to ensure robust results.Materials and methodsWe conducted a phenomenological qualitative study with YAs diagnosed with any cancer type between ages 25 and 39 years old in the last 5 years. Participants took part in interviews or focus groups and data were analysed using inductive thematic analysis. Results were shaped in an iterative process with the initial coders and four YA patients who did not participate in the study to improve the rigor of the results.ResultsSixty-five YAs with a range of tumour types participated. We identified seven themes and 13 subthemes. YAs found navigating the healthcare system difficult and commonly experienced prolonged diagnostic pathways. Participants felt under-informed about clinical details and the long-term implications of side-effects on daily life. YAs found online resources overwhelming but also a source of information and treatment support. Some patients regretted not discussing fertility before cancer treatment or felt uninformed or rushed when making fertility preservation decisions. A lack of age-tailored content or age-specific groups deterred YAs from accessing psychological support and rehabilitation services.ConclusionsYAs with cancer may miss some benefits provided to teenagers and young adults in age-tailored cancer services. Improving services for YAs in adult settings should focus on provision of age-specific information and access to existing relevant support

    Generating Performance Portable Code using Rewrite Rules: From High-Level Functional Expressions to High-Performance OpenCL Code

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    Computers have become increasingly complex with the emergence of heterogeneous hardware combining multicore CPUs and GPUs. These parallel systems exhibit tremendous computational power at the cost of increased programming effort resulting in a tension between performance and code portability. Typically, code is either tuned in a low-level imperative language using hardware-specific optimizations to achieve maximum performance or is written in a high-level, possibly functional, language to achieve portability at the expense of performance. We propose a novel approach aiming to combine high-level programming, code portability, and high-performance. Starting from a high-level functional expression we apply a simple set of rewrite rules to transform it into a low-level functional representation, close to the OpenCL programming model, from which OpenCL code is generated. Our rewrite rules define a space of possible implementations which we automatically explore to generate hardware-specific OpenCL implementations. We formalize our system with a core dependently-typed λ-calculus along with a denotational semantics which we use to prove the correctness of the rewrite rules. We test our design in practice by implementing a compiler which generates high performance imperative OpenCL code. Our experiments show that we can automatically derive hardware-specific implementations from simple functional high-level algorithmic expressions offering performance on a par with highly tuned code for multicore CPUs and GPUs written by experts

    Cultural Orientations of sport managers

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    Various interpretations of sport management are cultural constructs underpinned by core assumptions and values held by members of professional communities. Sport managers world wide share common problems, but differ in how they resolve them. These universal differences emerge from the relationships they form with other people, and their attitude to time, activities and the natural environment. This paper examines the role of sport managers’ cultural orientations in the interpretation and practice of sport management. Using a multiple dimension model (Hampden-Turner and Trompenaars, 2000) it sketches the cultural profiles of fifteen sport managers from seven countries. A combination of methods was employed including questionnaires, interviews and participant observation. It is contended that the culture of sport management concerns a social process by which managers get involved in reconciling seven fundamental cultural dilemmas in order to perform tasks and achieve certain ends. Thus, a knowledge of the cultural meaning of sport management in a particular country would equip sport managers with a valuable tool in managing both the cultural diversity of their own work forces and in developing appropriate cross-cultural skills needed for running international events, marketing campaigns, sponsorship deals and joint ventures

    ​Residential mobility:Towards progress in mobility health research

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    Research into health disparities has long recognized the importance of residential mobility as a crucial factor in determining health outcomes. However, a lack of connectivity between the health and mobility literatures has led to a stagnation of theory and application on the health side, which lacks the detail and temporal perspectives now seen as critical to understanding residential mobility decisions. Through a critical re-think of mobility processes with respect to health outcomes and an exploitation of longitudinal analytical techniques, we argue that health geographers have the potential to better understand and identify the relationship that residential mobility has with health.“The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 615159 (ERC Consolidator Grant DEPRIVEDHOODS, Socio-spatial inequality, deprived neighbourhoods, and neighbourhood effects)”OLD Urban Renewal and Housin
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