2,585 research outputs found

    Personality and Cognitive Ability as Predictors of Effective Performance at Work

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    Abstract Conclusions about the validity of cognitive ability and personality measures based on meta-analyses published mostly in the past decade are reviewed at the beginning of this article. Research on major issues in selection that affect the use and interpretation of validation data are then discussed. These major issues include the dimensionality of personality, the nature and magnitude of g in cognitive ability measures, conceptualizations of validity, the nature of the job performance domain, trade-offs between diversity and validity, reactions to selection procedures, faking on personality measures, mediator and moderator research on test-performance relationships, multilevel issues, Web-based testing, the situational framing of test stimuli, and the context in which selection occurs

    Advanced extravehicular activity systems requirements definition study. Phase 2: Extravehicular activity at a lunar base

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    The focus is on Extravehicular Activity (EVA) systems requirements definition for an advanced space mission: remote-from-main base EVA on the Moon. The lunar environment, biomedical considerations, appropriate hardware design criteria, hardware and interface requirements, and key technical issues for advanced lunar EVA were examined. Six remote EVA scenarios (three nominal operations and three contingency situations) were developed in considerable detail

    Ice-Tethered Profiler observations of the double-diffusive staircase in the Canada Basin thermocline

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    Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): C00A02, doi:10.1029/2008JC004829.Six Ice-Tethered Profilers (ITP), deployed in the central Canada Basin of the Arctic Ocean between 2004 and 2007, have provided detailed potential temperature and salinity measurements of a double-diffusive staircase at about 200–300 m depth. Individual layers in the staircase are of order 1 m in vertical height but appear to extend horizontally for hundreds of kilometers, with along-layer gradients of temperature and salinity tightly related. On the basis of laboratory-derived double-diffusive flux laws, estimated vertical heat fluxes through the staircase are in the range 0.05–0.3 W m−2, only about one tenth of the estimated mean surface mixed layer heat flux to the sea ice. It is thus concluded that the vertical transport of heat from the Atlantic Water in the central basin is unlikely to have a significant impact to the Canada Basin ocean surface heat budget. Icebreaker conductivity-temperature-depth data from the Beaufort Gyre Freshwater Experiment show that the staircase is absent at the basin periphery. Turbulent mixing that presumably disrupts the staircase might drive greater flux from the Atlantic Water at the basin boundaries and possibly dominate the regionally averaged heat flux.Funding for construction and deployment of the prototype ITPs was provided by the National Science Foundation Oceanographic Technology and Interdisciplinary Coordination (OTIC) Program and Office of Polar Programs (OPP) under grant OCE-0324233. Continued support for the ITP field program and data analysis has been provided by the OPP Arctic Sciences Section under awards ARC-0519899, ARC-0631951, ARC-0713837, and internal WHOI funding

    Acoustic detection of oceanic double-diffusive convection : a feasibility study

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    Author Posting. © American Meteorological Society, 2010. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 27 (2010): 580-593, doi:10.1175/2009JTECHO696.1.The feasibility of using high-frequency acoustic scattering techniques to map the extent and evolution of the diffusive regime of double-diffusive convection in the ocean is explored. A scattering model developed to describe acoustic scattering from double-diffusive interfaces in the laboratory, which accounted for much of the measured scattering in the frequency range from 200 to 600 kHz, is used in conjunction with published in situ observations of diffusive-convection interfaces to make predictions of acoustic scattering from oceanic double-diffusive interfaces. Detectable levels of acoustic scattering are predicted for a range of different locations in the world’s oceans. To corroborate these results, thin acoustic layers detected near the western Antarctic Peninsula using a multifrequency acoustic backscattering system are shown to be consistent with scattering from diffusive-convection interfaces.TR is grateful to the Natural Sciences and Engineering Research Council of Canada Discovery Grant and University Faculty Award Programs, which support her work at Dalhousie University

    Laboratory observations of double-diffusive convection using high-frequency broadband acoustics

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    Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Experiments in Fluids 46 (2009): 355-364, doi:10.1007/s00348-008-0570-9.High-frequency broadband (200-300 kHz) acoustic scattering techniques have been used to observe the diffusive regime of double-diffusive convection in the laboratory. Pulse compression signal processing techniques allow 1) centimetre-scale interface thickness to be rapidly, remotely, and continuously measured, 2) the evolution, and ultimate merging, of multiple interfaces to be observed at high-resolution, and 3) convection cells within the surrounding mixed layers to be observed. The acoustically measured interface thickness, combined with knowledge of the slowly-varying temperatures within the surrounding layers, in turn allows the direct estimation of double-diffusive heat and buoyancy fluxes. The acoustically derived interface thickness, interfacial fluxes and migration rates are shown to support established theory. Acoustic techniques complement traditional laboratory sampling methods and provide enhanced capabilities for observing the diffusive regime of double-diffusion in the ocean.Funding for this project was provided by the Ocean Acoustics program at the Office of Naval Research, and by the WHOI Cecil and Ida Greene Technology Award

    Explaining counterterrorism in the UK: Normal politics, securitized politics or performativity of the neoliberal state?

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    This paper seeks to explore the politics of counter terrorism in the UK. It argues that for a number of reasons, counter terrorism policy has been separated off from other policy areas and seen as securitised, exceptional or just different. The paper argues that such a separation from “normal” politics is problematic, both conceptually and empirically. It argues that much can be gained by considering counter terrorism policy through the lenses, concepts and debates which feature in other areas of British politics. The paper then examines two such lenses/debates – depoliticisation and neoliberalism. An argument is developed that counter terrorism policy is not, in the main, depoliticised, but rather overt, politicised and visible. This prominence, it is argued, is due to the ways in which neoliberalism has reduced many of the traditional roles of the state. Drawing on the work of Wacquant and Hall, the paper argues that in the absence of such traditional roles, counter terrorism offers the state an opportunity to perform its own “stateness”, to visibly display its sovereign power in a context of ever more (self-imposed) diminished powers

    Status Report of the DPHEP Study Group: Towards a Global Effort for Sustainable Data Preservation in High Energy Physics

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    Data from high-energy physics (HEP) experiments are collected with significant financial and human effort and are mostly unique. An inter-experimental study group on HEP data preservation and long-term analysis was convened as a panel of the International Committee for Future Accelerators (ICFA). The group was formed by large collider-based experiments and investigated the technical and organisational aspects of HEP data preservation. An intermediate report was released in November 2009 addressing the general issues of data preservation in HEP. This paper includes and extends the intermediate report. It provides an analysis of the research case for data preservation and a detailed description of the various projects at experiment, laboratory and international levels. In addition, the paper provides a concrete proposal for an international organisation in charge of the data management and policies in high-energy physics

    A Measurement of Rb using a Double Tagging Method

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    The fraction of Z to bbbar events in hadronic Z decays has been measured by the OPAL experiment using the data collected at LEP between 1992 and 1995. The Z to bbbar decays were tagged using displaced secondary vertices, and high momentum electrons and muons. Systematic uncertainties were reduced by measuring the b-tagging efficiency using a double tagging technique. Efficiency correlations between opposite hemispheres of an event are small, and are well understood through comparisons between real and simulated data samples. A value of Rb = 0.2178 +- 0.0011 +- 0.0013 was obtained, where the first error is statistical and the second systematic. The uncertainty on Rc, the fraction of Z to ccbar events in hadronic Z decays, is not included in the errors. The dependence on Rc is Delta(Rb)/Rb = -0.056*Delta(Rc)/Rc where Delta(Rc) is the deviation of Rc from the value 0.172 predicted by the Standard Model. The result for Rb agrees with the value of 0.2155 +- 0.0003 predicted by the Standard Model.Comment: 42 pages, LaTeX, 14 eps figures included, submitted to European Physical Journal
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