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Participants in a statewide family preservation program were classified on the basis of income level and enrollment in public assistance. These variables, along with other economic, parent, and child risk factors, were used to predict the probability of out-of-home placements at the close of this intervention program. Results revealed that neither low income nor receiving public assistance was predictive of having a child removed from the home. Higher levels of child-centered risk and parent-centered risk were the only consistent predictors of placement outcomes. Additional analyses revealed that family characteristics (e.g., history of psychiatric care, prior child placements, and involvement with the legal system) also were typical of families experiencing out-of-home placements. This study challenges the stereotype of low-income or welfare families being at greater risk of having a child removed from their home. Findings are discussed in the context of recent welfare reform initiatives and implications for future family policy research.  相似文献   
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The idea that there are certain "laws" of learning (similarity, contrast, contiguity) can be traced to Aristotle. He maintained that external stimuli cause small movements in the vessels to the dominant heart, the vestiges of which can be linked to one another. Aristotle's laws of learning were incorporated into the writings of Hobbes, Locke, and Berkeley, men who said nothing about the physiological correlates of mental associations. This left the door open for David Hartley to combine mental associationism with the Newtonian idea that sensations can cause minute particle vibrations in the nerves. Hartley's amalgam of psychology, philosophy, and neurology was first presented in 1746, as a "trial balloon" at the end a little-known monograph on a treatment for kidney stones. It was repeated three years later in his better-known Observations on Man. In many ways, modern psychobiological connectionism can be traced back to Hartley's Conjectures of 1746, in which Aristotle's original thoughts were modified with then current ideas about functions of the mind and the nervous system.  相似文献   
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ABSTRACT. Average monthly price data from twelve hinterland markets and the Houston port price for wheat are studied in a cointegration framework using the Engle-Granger "two-step" procedure and Johansen's maximum likelihood procedure. Out-of-sample forecasts from an error correction model are compared to those from a vector autoregression fit to levels and a univariate autoregression fit to first differences. This comparison suggests that modeling these (cointegrated) data as a levels vector autoregression, rather than as an error-correction process, results in significantly higher error bias, but lower error variance, at long horizons.  相似文献   
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ABSTRACT. Total cleared area in a von Thünen land-use model drives an atmosphere externality which depresses agricultural productivity uniformly throughout the region. Exogenous events that encourage clearance and use of a larger cultivated area (output price or population increase) exacerbate the externality. Imposition of a simple, corrective tax on land rents does not reverse these patterns but does mitigate the increase in the externality and leaves cultivators with higher incomes than they would obtain without the tax. We examine an optimal tax on land rents, designed to maximize the social value of land rents in the region, and an output tax.  相似文献   
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A multi-regional framework is developed in order to analyze net migration over time to all 10 Canadian provinces within an integrated system of equations. "An extended gravity model is the basis for the equation specification and the use of constrained econometric estimation techniques allows for the provincial interdependence of the migration decision while at the same time ensuring that an important system-wide requirement is respected." The model is estimated using official Canadian data for the 1960s and 1970s. "The results suggest the predominance of the push factor for interprovincial migration for most provinces, although net migration to the Atlantic provinces is also shown to be subject to pull forces from the rest of the country." The effects of wage rate variables, unemployment, and political disturbances in Quebec on inter-provincial migration are noted.  相似文献   
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