136,639 research outputs found

    Mood and creativity: an appraisal tendency perspective

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    There is a strong relationship between the mood one is in, and the way one performs creatively. Previous research has shown that this relationship is complex. In this paper we argue that this complexity partly lies in a faulty conceptualization of mood. We will argue that an appraisal tendency perspective on moods will help to further clarify the relationship between mood and creativity. To support this argument we will highlight some inconsistencies in previous research, and use the appraisal tendency perspective on mood to develop predictions that help explain these inconsistencies and develop new directions for mood-creativity research. Future research is required to assess the accuracy of these predictions

    A Cosmic Watershed: the WVF Void Detection Technique

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    On megaparsec scales the Universe is permeated by an intricate filigree of clusters, filaments, sheets and voids, the Cosmic Web. For the understanding of its dynamical and hierarchical history it is crucial to identify objectively its complex morphological components. One of the most characteristic aspects is that of the dominant underdense Voids, the product of a hierarchical process driven by the collapse of minor voids in addition to the merging of large ones. In this study we present an objective void finder technique which involves a minimum of assumptions about the scale, structure and shape of voids. Our void finding method, the Watershed Void Finder (WVF), is based upon the Watershed Transform, a well-known technique for the segmentation of images. Importantly, the technique has the potential to trace the existing manifestations of a void hierarchy. The basic watershed transform is augmented by a variety of correction procedures to remove spurious structure resulting from sampling noise. This study contains a detailed description of the WVF. We demonstrate how it is able to trace and identify, relatively parameter free, voids and their surrounding (filamentary and planar) boundaries. We test the technique on a set of Kinematic Voronoi models, heuristic spatial models for a cellular distribution of matter. Comparison of the WVF segmentations of low noise and high noise Voronoi models with the quantitatively known spatial characteristics of the intrinsic Voronoi tessellation shows that the size and shape of the voids are succesfully retrieved. WVF manages to even reproduce the full void size distribution function.Comment: 24 pages, 15 figures, MNRAS accepted, for full resolution, see http://www.astro.rug.nl/~weygaert/tim1publication/watershed.pd

    Superfluid vortices in neutron stars

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    A microscopic, quantum mechanical model for neutron vortices in the crust of a neutron star is presented. After a brief introduction to the Bogoliubov- de Gennes equations, which form the basis for our calculations, we present results for density distributions, vortex core sizes and vortex energies, both for an isolated neutron vortex and for the case when the vortex core overlaps with a cylindrical nucleus. Earlier results on the vortex core size are confirmed, indicating a much less dramatic variation of the vortex core size with density than predicted by the BCS formula.Comment: 28 pages, 8 figures. To appear in Astronomy & Astrophysic

    A gradient bound for free boundary graphs

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    We prove an analogue for a one-phase free boundary problem of the classical gradient bound for solutions to the minimal surface equation. It follows, in particular, that every energy-minimizing free boundary that is a graph is also smooth. The method we use also leads to a new proof of the classical minimal surface gradient bound

    One-loop renormalisation of N=1/2 supersymmetric gauge theory

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    We show that N=1/2 supersymmetric gauge theory is renormalisable at one loop, but only after gauge invariance is restored in a non-trivial fashion.Comment: 11 pages, including 3 figures. Plain TeX. Uses Harvmac and epsf. Minor changes and reference adde

    The Effects of Medicaid and Medicare Reforms on the Elderly’s Savings and Medical Expenditures

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    We study a model in which retired single people optimally choose consumption, medical spending and saving while facing uncertainty about their health, lifespan and medical needs. This uncertainty is partially offset by insurance provided by the government and private institutions. We first show how well the model matches important features of the data and we analyze the degree of insurance provided by current programs. We then analyze the effects of some reforms, meant to capture changes in Medicaid and Medicare, on savings and medical expenditures.
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