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"An empirical test of the effects of exogenous shocks upon a region's population size is conducted in the framework of an equilibrium locational model. The model emphasizes the separation of endogenous from exogenous factors, a point omitted in most empirical studies of aggregate migration. Exogenous changes are manifested in the local relative cost of living and the local relative unemployment rate. Hypotheses are tested using a national sample of youth, in addition to census, data [for the United States]. Surprisingly, a simple measure of the size of shock to a regional economy has the greatest explanatory power compared to more sophisticated measures based on prior business cycles." 相似文献
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Norman R. Cloutier 《Journal of regional science》1988,28(3):415-419
ABSTRACT. The distribution of above-median income groups can be described accurately by OLS regression of the Pareto distribution. The excellent fit of log-linear regression has led some researchers to conclude that extrapolated income measures in the open end of the distribution are reliable. The analysis of income distribution data for metropolitan areas reveals: (1) that OLS tends to consistently overestimate the number of families in the tail, and (2) that the overestimation can have serious implications for hypothesis testing. 相似文献
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"This paper presents a two-sector dynamic model of regional population change. The model contains a migration equation, an earnings equation, and an amenity equation for each region. In the context of this model, migration is seen as a disequilibrium process through which the regional populations move towards equilibrium positions. Migration occurs when one region is perceived to be superior to the other on the basis of its earnings and amenity levels. Equilibrium is achieved when population movements between the regions eliminate any differences in their relative attractiveness. A comparative-static analysis of the model is presented to analyze the effects of policy changes and exogenous shocks on the distribution of population among the regions." The geographical focus is on the United States. 相似文献
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A palaeoecological approach was undertaken to investigate the last 400 years of change in vegetation, fire, nutrient mobility, lake productivity and erosion associated with Aboriginal and European land-use practices in a forested environment in eastern Victoria. Melaleuca ericifolia scrub, although present prior to European settlement, has expanded around Lake Curlip in the last 200 years, primarily due to the action of fire on a forest already weakened by drought. A fern understorey has declined in extent and a more open aspect has developed in the forest. Fire has been a major component of vegetation dynamics in the historical period. Erosion rates were comparatively low and associated with fire during prehistoric times, but after European settlement its increase is more closely related to land clearance and flooding than fire. The response of vegetation to both anthropogenic and natural influences changed during the historical period. Although fire is an integral part of vegetation change, it is not an over-riding effect at Lake Curlip. Drain construction in the swamp has reduced the impact that any accumulation of pasture improvement chemicals may have had on eutrophication of the lake. 相似文献
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Glass finds from the first Bulgarian capital, Pliska, have been analysed by instrumental neutron activation analysis. The analytical data, together with previous results from analysis of glass samples from the second Bulgarian capital, Preslav, were subjected to cluster and discriminant analysis. The local origin of part of the analysed samples was proven and some conclusions about the technology of production were possible. 相似文献
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