18,111 research outputs found

    Policy-induced Internal Migration: An Empirical Investigation of the Canadian Case

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    We investigate the influence of public policy on interprovincial migration in Canada using new aggregated migration data for 1974-1996, the longest period studied so far. We consider the consequences of regional variation in a variety of policies, and also investigate the effects of certain extraordinary events in Quebec and in the Atlantic provinces. The results indicate that while the changing bias in the unemployment insurance system may have induced some people to move to the relatively high unemployment Atlantic region, the resulting flows are likely too small to have altered regional unemployment rates. In contrast, political events in Quebec in the 1970's and the closing of the cod fishery in 1992 appear to be associated with large changes in migration patterns.migration, regional disparity, public policy, unemployment insurance, conditional logit, taxation data

    What do we Know about the Relationship between Regionalized Aspects of the Unemployment Insurance System and Internal Migration in Canada?

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    The purpose of this paper is to critically review the past four decades of empirical research on the relationship between internal migration and regional variation in the generosity of Canada’s unemployment insurance system. It has long been argued that because the Canadian insurance system is more generous towards people who live in relatively disadvantaged regions, it retards the out-migration that is part of the market process, thereby slowing economic development and contributing to the persistence of regional inequality in earned incomes. The survey shows, however, that there is no evidence in the empirical literature that regional variation in the generosity of the insurance system has altered internal migration patterns in Canada in a substantial manner.regional variation in unemployment insurance generosity, internal migration, interprovincial migration, earned income, comprehensive income differentials, index of insurance generosity, labour market attachment, conditional logit model

    Changes in insulin and insulin signaling in Alzheimer\u27s disease: Cause or consequence?

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    Individuals with type 2 diabetes have an increased risk for developing Alzheimer’s disease (AD), although the causal relationship remains poorly understood. Alterations in insulin signaling (IS) are reported in the AD brain. Moreover, oligomers/fibrils of amyloid-β (Aβ) can lead to neuronal insulin resistance and intranasal insulin is being explored as a potential therapy for AD. Conversely, elevated insulin levels (ins) are found in AD patients and high insulin has been reported to increase Aβ levels and tau phosphorylation, which could exacerbate AD pathology. Herein, we explore whether changes in ins and IS are a cause or consequence of AD

    Bigger Bursts From Merging Neutron Stars

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    GRB 990123 may have radiated more than one solar mass equivalent in just its gamma emissions. Though this may be within the upper limit of the binding energy available from neutron stars in the Schwarzschild metric, it is difficult to imagine a process with the required efficiency of conversion to gamma rays. Neutron stars of ~10 solar mass are permitted in the Yilmaz metric. A merger of two neutron stars of maximum mass could release approximately 10 solar mass equivalent binding energy.Comment: 5 pages, 1 figure, submitted to ApJ Letter

    Planetary image conversion task

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    The Planetary Image Conversion Task group processed 12,500 magnetic tapes containing raw imaging data from JPL planetary missions and produced an image data base in consistent format on 1200 fully packed 6250-bpi tapes. The output tapes will remain at JPL. A copy of the entire tape set was delivered to US Geological Survey, Flagstaff, Ariz. A secondary task converted computer datalogs, which had been stored in project specific MARK IV File Management System data types and structures, to flat-file, text format that is processable on any modern computer system. The conversion processing took place at JPL's Image Processing Laboratory on an IBM 370-158 with existing software modified slightly to meet the needs of the conversion task. More than 99% of the original digital image data was successfully recovered by the conversion task. However, processing data tapes recorded before 1975 was destructive. This discovery is of critical importance to facilities responsible for maintaining digital archives since normal periodic random sampling techniques would be unlikely to detect this phenomenon, and entire data sets could be wiped out in the act of generating seemingly positive sampling results. Reccomended follow-on activities are also included

    Dirichlet Process Hidden Markov Multiple Change-point Model

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    This paper proposes a new Bayesian multiple change-point model which is based on the hidden Markov approach. The Dirichlet process hidden Markov model does not require the specification of the number of change-points a priori. Hence our model is robust to model specification in contrast to the fully parametric Bayesian model. We propose a general Markov chain Monte Carlo algorithm which only needs to sample the states around change-points. Simulations for a normal mean-shift model with known and unknown variance demonstrate advantages of our approach. Two applications, namely the coal-mining disaster data and the real United States Gross Domestic Product growth, are provided. We detect a single change-point for both the disaster data and US GDP growth. All the change-point locations and posterior inferences of the two applications are in line with existing methods.Comment: Published at http://dx.doi.org/10.1214/14-BA910 in the Bayesian Analysis (http://projecteuclid.org/euclid.ba) by the International Society of Bayesian Analysis (http://bayesian.org/

    Scaling behavior in economics: II. Modeling of company growth

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    In the preceding paper we presented empirical results describing the growth of publicly-traded United States manufacturing firms within the years 1974--1993. Our results suggest that the data can be described by a scaling approach. Here, we propose models that may lead to some insight into these phenomena. First, we study a model in which the growth rate of a company is affected by a tendency to retain an ``optimal'' size. That model leads to an exponential distribution of the logarithm of the growth rate in agreement with the empirical results. Then, we study a hierarchical tree-like model of a company that enables us to relate the two parameters of the model to the exponent β\beta, which describes the dependence of the standard deviation of the distribution of growth rates on size. We find that β=lnΠ/lnz\beta = -\ln \Pi / \ln z, where zz defines the mean branching ratio of the hierarchical tree and Π\Pi is the probability that the lower levels follow the policy of higher levels in the hierarchy. We also study the distribution of growth rates of this hierarchical model. We find that the distribution is consistent with the exponential form found empirically.Comment: 19 pages LateX, RevTeX 3, 6 figures, to appear J. Phys. I France (April 1997
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