40,105 research outputs found

    Writing in Response to Reading: Correspondences About Books

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    Pointlike electric charge in gravitational field theory

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    The existence of charged elementary 'point particles' still is a basically unsolved puzzle in theoretical physics. The present work takes a fresh look at the problem by including gravity---without resorting to string theory. Using Einstein's equations for the gravitational fields in a general static isotropic metric with the full energy-momentum tensor (for the charged material mass and the electromagnetic fields) as the source term, a novel exact solution with a well-defined characteristic radius emerges where mass and charge accumulate: rc=rero/2r_{\rm c}{=}\sqrt{r_{\rm e}r_o/2}---with re=Q2 ⁣/4πϵomc2r_{\rm e}{=}Q^2\!/4\pi\epsilon_omc^2 being the 'classical' radius associated with the total charge QQ and where ro=2mG/c2r_o{=}2mG/c^2 is the Schwarzschild radius belonging to the observable mass mm (for the electron one has re1015r_{\rm e}{\approx}10^{-15}m and ro1057r_o{\approx}\,10^{-57}m). The resulting 'Einstein-Maxwell' gravitational electron radius can also be written as rc=Pαer_{\rm c}{=}\ell_{\rm P}\sqrt{\alpha_{\rm e}}, where P=G/c31035\ell_{\rm P}{=}\sqrt{\hbar G/c^3}{\approx}10^{-35}m is the fundamental Planck length and αe=e2 ⁣/4πϵoc1/137\alpha_{\rm e}{=}e^2\!/4\pi\epsilon_o\hbar c{\approx}1/137 the fine-structure constant, which yields rcelectron=1.38063×1036r_{\rm c}^{\rm electron}{=}1.38063{\times}10^{-36}m.Comment: 13 pages, 2 figure

    Reflections on a Snowy Day

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    World Religion Database

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    This article reviews the new database released by Brill entitled World Religion Database (WRD). It compares WRD to other religious demography tools available and rates the database on a 5 point scale

    Calming the Storm: The Story of a Second Grade Writing Project

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    \u27Art\u27 They Can\u27t See, Lines, Anatomy of Decomposing, October on Danford Creek, Wing Bone, and Taxidermy

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    The following document includes a selection and submission for the Hilltop Review. Within the file the reader will find five (5) poems and one (1) micro fiction piece. The poems are titled \u27Art\u27 They Can\u27t See, Lines, Anatomy of Decomposing, October on Danford Creek, and Wing Bone. These poems incorporate darkness, illness, social issues, and a manifestation and exploration of the human condition. The Microfiction text titled Taxidermy, details the interaction between two siblings showcasing the younger sister\u27s mental illness by detailing the delusional and obsessive behavior of this character. These texts have been workshopped under the instruction of poets, William Olsen & Nancy Eimers and Fiction writer, Thisbe Nissen at Western Michigan University

    Unemployment durations after temporary work: Evidence for Great Britain and Germany

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    Unemployment durations are determined by a number of factors. According to mainstream economics theory, unemployment durations are shorter in a more flexible labour market. In this paper, we hypothesize that workers who had a temporary contract before the spell of unemployment will experience shorter spells of unemployment than workers who had a permanent contract before. We adopt a flexible hazard rate model with a nonparametric baseline to analyse data on unemployment spells in Germany and Great Britain for the period 1991-2001. The two datasets allow for an international comparison of the institutional differences between the two countries. We find no evidence of shorter unemployment spells for previous temporary workers neither in Great-Britain nor in Germany. Results suggest that a labour market policy of promoting temporary work will not necessarily lead to lower unemployment since these policies increase the probability of becoming unemployed without being able to fulfil the promise of shorter unemployment spells.unemployment duration, temporary employment, job search model, nonparametric hazard model, Great-Britain, Germany

    Non-standard employment and mobility in the Netherlands

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    In the last 25 years the number of flexible jobs has been expanding in most European countries. For example, in the Netherlands in 1995, about 11 per cent of workers was working in a fixed-term temporary job and about 37 per cent of workers was working in a part-time job. Seven years later, in 2002 these percentages had increased to 14 per cent and 44 per cent. It should be noted however, that the increase in temporary jobs already reached 13 per cent in 1998 and is fairly stable since, whereas the percentage of part-time jobs is still increasing in 2002. For the purpose of this paper, the focus will be on several forms of contractual flexibilisation: temporary contracts , small part-time contracts , on-call and replacement contracts, casual and seasonal work and work with temporary work agencies. These jobs are all defined as non-standard employment.The labour market in the Netherlands is characterised by quite some mobility between the various labour market states. The high mobility rates between non-standard and standard jobs, except for the small jobs and on-call contracts as part of non-standard employment, provide arguments for defending the hypothesis that the Dutch labour market is not characterised by a clear-cut segmentation of non-standard and standard jobs. An important finding is that there is a high degree of path dependence in labour market transitions. Earlier experience in standard employment increases the transition probabilities into standard employment, both for the nonemployed and for non-standard workers. Earlier experience in either non-standard or non-standard employment also reduces the probability of ‘falling back’ into nonemployment. Previous unemployment does not reduce the chances of finding a job for the nonemployed but does reduce the chances of finding a standard job for non-standard workers.job mobility; non-standard employment; panel data; Netherlands

    Studying Organisational Topology with Simple Computational Models

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    The behaviour of many complex systems is influenced by the underlying network topology. In particular, this applies to social systems in which people or organisational units collaboratively solve problems. Network rewiring processes are one useful tool in understanding the relationship between network topology and behaviour. Here we use the Kawachi network rewiring process, together with three simple simulation models of organisational collaboration, to investigate the network characteristics that influence performance. The simulation models are based on the Assignment Problem, the Kuramoto Model from physics, and a novel model of collaborative problem-solving which involves finding numbers with certain characteristics, the existence of which is guaranteed by Lagrange\'s Theorem. For all three models, performance is best when the underlying organisational network has a low average distance between nodes. In addition, the third model identified long-range connectivity between nodes as an important predictor of performance. The commonly-used clustering coefficient, which is a measure of short-range connectivity, did not affect performance. We would expect that long-range network connectivity would also influence the behaviour of other complex systems displaying global self-synchronization. The paper also demonstrates the utility of simple computational models in studying issues of organisational topology.Network Rewiring, Small World Networks, Self-Synchronization, Agent Simulation, Collaboration, Problem Solving
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