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Newly available geographical information from the Panel Study of Income Dynamics (PSID) is used to estimate a variety of relationships involving high-poverty metropolitan census tracts. The longitudinal data from the PSID show a great deal of geographical mobility even for persistently poor adults, with as many as one fourth of certain groups of these entering and leaving poor urban census tracts in a year. At the same time, solution of the transition matrices for various groups—whites and blacks of various income classes, in families with and without children, living in different types of census tracts—in the early 1980s shows the gradual emptying out of poor urban tracts, particularly of whites and blacks in families without children. As a consequence, despite the great degree of geographical “churning,” poor urban areas gradually become poorer, blacker, and the home of a larger share of black families with children. Some of these aggregate trends had been noticed by researchers comparing these areas in the 1970 and 1980 censuses; our more up-to-date results demonstrate the relationships between the micro and macro data.  相似文献   
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I propose and test a theoretical framework that explains institutional change in international relations. Like firms in markets, international institutions are affected by the underlying characteristics of their policy areas. Some policy areas are prone to produce institutions facing relatively little competition, limiting the outside options of member states and impeding redistributive change. In comparison, institutions facing severe competition will quickly reflect changes in underlying state interests and power. To test the theory empirically, I exploit common features of the Bretton Woods institutions—the International Monetary Fund and World Bank—to isolate the effect of variation in policy area characteristics. The empirical tests show that, despite having identical membership and internal rules, bargaining outcomes in the Bretton Woods institutions have diverged sharply and in accordance with the theory.  相似文献   
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Most studies that have focused on female serial killers (FSKs), although informative, have examined limited sample sizes. We consulted mass media reports of demographics, motives, methods, mental health, and victim characteristics of 64 FSKs who committed their crimes in the US from 1821 to 2008. Consistent with other studies, our data showed that FSKs were typically White, educated, have been married, and held a caregiving role (e.g. mother, health care worker). Nearly 40% of FSKs in this sample experienced some form of mental illness. Their most common motive for murder was financial gain, and their most common method of killing was poisoning. FSKs knew all or most of their victims, and most were related to their victims. In all cases, FSKs targeted at least one victim who was a child, elderly, or infirm – those who had little chance of fighting back. We interpret these killers’ behaviors from clinical and evolutionary angles.  相似文献   
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Four fluorescent fingerprint powders (RedWop?, GreenWop?, Basic Yellow?, and Yellow Powder?) were evaluated as a marker for blow fly larvae. Administration methods included ingestion (high vs. low concentration) or topical. Ingestion of high concentrations of Basic Yellow? and RedWop? caused higher larval mortality. Basic Yellow? delayed development and adult emergence while RedWop? and Yellow Powder? had a significant effect on particular stages of development, however, emergence time was not altered. Optimal administration is through ingestion at low concentration levels (<10%) or topically, with GreenWop? demonstrating minimal adverse effects. Optimum wavelength for discrimination between powders was 450 nm. This research can aid in investigative training to increase visibility of larval and pupal blow flies. It can also be used in entomological studies to differentiate between larval blow flies (or other dipteran) species or individuals to further understand complex interactions and behavior during larval development.  相似文献   
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