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Multistage ranked-set sampling (MRSS) is a generalization of ranked-set sampling in which multiple stages of ranking are used. It is known that for a fixed distribution under perfect rankings, each additional stage provides a gain in efficiency when estimating the population mean. However, the maximum possible efficiency for the MRSS sample mean relative to the simple random sampling sample mean has not previously been determined. In this paper, we provide a method for computing this maximum possible efficiency under perfect rankings for any choice of the set size and the number of stages. The maximum efficiency tends to infinity as the number of stages increases, and, for large numbers of stages, the efficiency-maximizing distributions are symmetric multi-modal distributions where the number of modes matches the set size. The results in this paper correct earlier assertions in the literature that the maximum efficiency is bounded and that it is achieved when the distribution is uniform.  相似文献   
23.
It has long been recognized that women are at a higher risk than men to develop depression and that such risk is particularly associated with reproductive cycle events. Recent long-term, prospective studies have demonstrated that the transition to menopause is associated with higher risk for new onset and recurrent depression. A number of biological and environmental factors are independent predictors for depression in this population, including the presence of hot flushes, sleep disturbance, history of severe premenstrual syndrome or postpartum blues, ethnicity, history of stressful life events, past history of depression, body mass index, socioeconomic status and the use of hormones and antidepressants. Accumulated evidence suggests that ovarian hormones modulate serotonin and noradrenaline neurotransmission, a process that may be associated with underlying pathophysiological processes involved in the emergence of depressive symptoms during periods of hormonal fluctuation in biologically predisposed subpopulations. Transdermal estradiol and serotonergic and noradrenergic antidepressants are efficacious in the treatment of depression and vasomotor symptoms in symptomatic, midlife women. The identification of individuals whom might be at a higher risk for depression during menopausal transition could guide preventive strategies for this population.  相似文献   
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This study evaluates the social and demographic structure of poverty migration during the 1985–90 period based on an analysis of recent census data. Particular attention is given to the roles of two policy-relevant factors that are proposed to be linked to poverty migration. The first of these is the role of immigration from abroad and its effect on the net out-migration of longer-term residents with below-poverty incomes, from States receiving the highest volume of immigrants. Such a response, it is argued, could result from job competition or other economic and social costs associated with immigration. The second involves the poverty population magnet effect associated with State welfare benefits (AFDC and Food Stamp payments) which has come under renewed scrutiny in light of the impending reform of the federal welfare program. The impact of both of these factors on interstate poverty migration is evaluated in a broader context that takes cognizance of other sociodemographic subgroups, and State-level attributes that are known to be relevant in explaining internal migration. This research employs an exceptionally rich data base of aggregate migration flows, specially tabulated from the full migration sample of the 1990 US census (based on the residence 5 years ago question). It also employs an analysis technique, the nested logit model, which identifies separately the push and pull effects of immigration, welfare benefits, and other State attributes on the migration process. Our findings are fairly clear. The high volume of immigration to selected US Statesdoes affect a selective out-migration of the poverty population, which is stronger for whites, Blacks and other non-Asian minorities as well as the least-educated. These results are consistent with arguments that internal migrants are responding to labor market competition from similarly educated immigrants. Moreover, we found that the impact of immigration occurs primarily as a push rather than a reduced pull. In contrast, State welfare benefits exert only minimal effects on the interstate migration of the poverty population—either as pulls or pushes, although some demographic segments of that population are more prone to respond than others. In addition to these findings, our results reveal the strong impact that a State's racial and ethnic composition exerts in both retaining and attracting migrants of like race and ethnic groups. This suggests the potential for a greater cross-state division in the US poverty population, by race and ethnic status.Data Used: 1990 US census tabulations of full migration (residence 5 years ago) sample. Note: Detailed 1990 census statistics on migration of the poverty and nonpoverty populations for individual states can be found in: William H. Frey Immigration and Internal Migration for US States: 1990 Census Findings by Poverty Status and Race, Population Studies CenterResearch Report No. 94-320.This research is supported by the University of Wisconsin Institute for Research on Poverty Small Grants Program and by NICHD grant No. R01 HD29725. The migration data for this paper were prepared at the Population Studies Center, University of Michigan from 1990 US Census files. The authors acknowledge Cathy Sun for computer programming assistance, and Ron Lue-Sang for preparing maps and graphics.  相似文献   
25.
Urban scholars and planners look to evidence of recent gains in the number of nontraditional households as a potential source of increase to the population sizes and tax bases of declining central cities. While it is now well established that substantial gains in the numbers of small, nontraditional households have occurred since the 1950s, it has not been demonstrated that: (a) these households are more likely to relocate in the city than traditional family households (husband-wife with children under 18); or (b) their cityward relocation patterns will significantly alter trends toward smaller city household populations. This paper addresses these questions by examining changes in city-suburb migration stream rates by household type over periods 1955–60, 1965–70 and 1970–75 for large metropolitan areas, and assesses their implications for potential changes in the aggregate sizes of city household populations.  相似文献   
26.
Population movement and city-suburb redistribution: An analytic framework   总被引:1,自引:0,他引:1  
William H. Frey 《Demography》1978,15(4):571-588
This paper introduces an analytic framework that can be used to assess the relationships between individual movement differentials and place characteristics, on the one hand, and aggregate mobility levels and city-suburb population change (in size or composition), on the other. Application of this framework using census data for individual metropolitan areas allows the analyst to decompose population changes due to net migration into contributing mobility streams and their component rates which are subject to unique community and individual influences. The paper provides both theoretical and empirical rationale for the framework, illustrates its use with 1970 census data, and discusses its implications for empirical research on city-suburb population redistribution.  相似文献   
27.
For some youth in foster care, the closest family or family‐like relationships are with the foster parents with whom they have lived for extended periods of time. Nonetheless, child welfare agencies often do not explore these relationships and the potential they may hold for youth for legal permanence through adoption or guardianship. Recognizing that social workers often lack resources to help them initiate permanency conversations, Casey Family Services, a direct service child welfare agency in the USA, developed a tool that social workers can use to explore youth's sense of emotional security with their foster parents and foster parents' sense of claiming and attachment with youth in their care. The research literature that suggests that emotional security is a critical component of successful permanence provided the foundation for the development of the Belonging and Emotional Security Tool (BEST). When used with youth and foster parents, the BEST was found to advance meaningful permanency conversations. The authors provide case examples of its use and discuss future directions for using the BEST and broadening its application.  相似文献   
28.
This paper examines the development of John Dewey's critique of Marxism. We trace the development of Dewey's critique from his early political writings and his political encounter with Leon Trotsky to his mature critique. We also examine how Dewey's concerns anticipate ideas expressed in the contemporary discussion of Marxian morality and how this discussion helps clarify Dewey's concerns.  相似文献   
29.
The effect of a confidentiality reminder was tested during atelephone survey of the general public of a metropolitan area.One-half of the sample was administered the reminder just priorto the demographic questions; the other half of the sample didnot receive the treatment. The results showed no significantdifferences on the distribution of nonsubstantive responsesbetween the two groups. There was some evidence that the confidentialityreminder had a negative effect on data quality.  相似文献   
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