120 research outputs found

    Maximally smooth Dirichlet interpolation from complete and incomplete sampling on the unit circle

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    This paper introduces a cost function for the smoothness of a continuous periodic function, of which only some samples are given. This cost function is important e.g. when associating samples in frequency bins for problems such as analytic singular or eigenvalue decompositions. We demonstrate the utility of the cost function, and study some of its complexity and conditioning issues

    Effect size and statistical power in the rodent fear conditioning literature - A systematic review

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    <div><p>Proposals to increase research reproducibility frequently call for focusing on effect sizes instead of p values, as well as for increasing the statistical power of experiments. However, it is unclear to what extent these two concepts are indeed taken into account in basic biomedical science. To study this in a real-case scenario, we performed a systematic review of effect sizes and statistical power in studies on learning of rodent fear conditioning, a widely used behavioral task to evaluate memory. Our search criteria yielded 410 experiments comparing control and treated groups in 122 articles. Interventions had a mean effect size of 29.5%, and amnesia caused by memory-impairing interventions was nearly always partial. Mean statistical power to detect the average effect size observed in well-powered experiments with significant differences (37.2%) was 65%, and was lower among studies with non-significant results. Only one article reported a sample size calculation, and our estimated sample size to achieve 80% power considering typical effect sizes and variances (15 animals per group) was reached in only 12.2% of experiments. Actual effect sizes correlated with effect size inferences made by readers on the basis of textual descriptions of results only when findings were non-significant, and neither effect size nor power correlated with study quality indicators, number of citations or impact factor of the publishing journal. In summary, effect sizes and statistical power have a wide distribution in the rodent fear conditioning literature, but do not seem to have a large influence on how results are described or cited. Failure to take these concepts into consideration might limit attempts to improve reproducibility in this field of science.</p></div

    Measuring smoothness of real-valued functions defined by sample points on the unit circle

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    In the context of extracting analytic eigen- or singular values from a polynomial matrix, a suitable cost function is the smoothness of continuous, real, and potentially symmetric periodic functions. This smoothness can be measured as the power of the derivatives of that function, and can be tied to a set of sample points on the unit circle that may be incomplete. We have previously explored the utility of this cost function, and here provide refinements by (i) analysing properties of the cost function and (ii) imposing additional constraints on its evaluation

    On the creation of thermal equations of state for use in Dioptas

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    Dioptas is a widely used software package for integrating and analysing 2-dimensional diffraction images. To help interpret the integrated diffraction profiles it produces, Dioptas users can input files that parameterise a material's thermal equation of state (EoS), enabling the positions of the Bragg peaks from that material to be calculated as a function of pressure and temperature. However, care is needed to ensure that these input files correctly describe the thermal EoS of interest. Here we describe the thermal EoS model used by Dioptas and show how existing thermal EoS should be reparameterised so as to be used correctly in Dioptas. Input EoS files suitable for use with Dioptas are provided for the following commonly-used pressure calibrants and pressure transmitting media: Al, Au, Cu, Mo, Nb, Pt, Ta, hcp-Fe, MgO, NaCl-B1, NaCl-B2, KCl-B2, and Ne.</p

    Building and sustaining Work Engagement – A participatory action intervention to increase Work Engagement in nursing staff

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    This study evaluated whether a participatory action research intervention with nursing staff on acute care older people NHS wards in the UK was effective for increasing work engagement. Mediation analyses between job resources, (social support, influence in decision-making), job demands, work-related needs (autonomy, competence, relatedness), and work engagement explored the presumed psychological mechanisms underlying the intervention. A nonrandomised, matched control group, pre-test, post-test design involved three intervention and five control wards. A significant decrease in relatedness, and a borderline significant decrease in competence, was observed in the intervention group compared to the control group, with no effect on work engagement (N=45). Work-related needs mediated between resources and work engagement, supporting the Job Demands-Resources model and Self-Determination Theory as an underlying explanatory theory. Intervention implementation was difficult, highlighting the need for participant and organisational readiness for change, and strong management support. This is the first known study to apply participatory techniques to increase work engagement in nursing staff and explore the underlying explanatory psychological mechanisms, offering a novel means of taking work engagement research forward. Crucially, it highlights the challenges involved in intervention research and the importance of including evaluations of intervention implementation alongside statistical evaluations to avoid erroneous conclusions

    Protocol for a retrospective, controlled cohort study of the impact of a change in Nature journals' editorial policy for life sciences research on the completeness of reporting study design and execution

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    In recent years there has been increasing concern about the rigor of laboratory research. Here we present the protocol for a study comparing the completeness of reporting of in vivo and in vitro research carried in Nature Publication Group journals before and after the introduction of a change in editorial policy (the introduction of a set of guidelines for reporting); and in similar research published in other journals in the same periods. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11192-016-1964-8) contains supplementary material, which is available to authorized users
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