Unbiased estimation of the parameter of a selected binomial population

The problem is to estimate the parameter of a selected binomial population. The selction rule is to choose the population with the greatest number of successes and, in the case of a tie, to follow one of two schemes: either choose the population with the smallest index or randomize among the tied populations. Since no unbiased estimator exists in the above case, we employ a second stage of sampling and take additional observations on the selected population. We find the uniformly minimum variance unbiased estimator (UMVUE) under the first tie break scheme and we prove that no UMVUE exists under the second. We find an unbiased estimator with desirable properties in the case where no UMVUE exists.     

Subjective Versus Objective Definitions of Homelessness: Are there Differences in Risk Factors among Heavy-Drinking Women?

Investigations with homeless populations have focused on those living on the streets or in shelters; few have examined phenomena based on respondents’ self-definitions as homeless or not. This investigation examined similarities and differences among risk factors (including mental health, substance abuse, religion/spirituality, social support, and risky sexual behaviors) using two definitions of homelessness: one where place of residence defined individuals as homeless (the ‘objective’ or traditional, definition) and another where respondents defined themselves as homeless (the ‘subjective’ definition). Data come from the baseline survey of the NIAAA-funded “Sister-to-Sister” study (n = 339) of heavy-drinking women. Subjectively defined homelessness was associated with higher rates of mental health and substance use disorders, lower rates of condom use, higher rates of trading sex for food, and less social support. Objectively defined homelessness was associated with higher rates of drinking in abandoned buildings, on the streets, and in public restrooms, more new sexual partners, and higher rates of trading sex for heroin and speedballs. Investigations failing to ask for subjective information may misattribute some factors to homelessness which may overestimate the effect of various factors on homelessness. Investigators should ask respondents to define their homelessness, or they lose an important dimension of the concept of homelessness.

望文生义的恶果

比窦娥还冤 1996年,笔者何震在加拿大职业发展学院北京分部做Bernard Liu先生的助手时,来自加拿大的Roseanne走进我的办公室和我聊天。我们聊得很投机,我指着桌子上的很多文件对她说：“平时工作太忙,我希望自己每天能工作24个小时,因为有一些不是很重要的但是必须做的工作总是抽不出时间”。Roseanne当时的回答是：“Henry（笔者的英文名字）,whatashame!”直到今天,我还清楚地记得我当时心里的一股无名怒火,     

元前文献图籍所载黄河河源

有关黄河河源的概念,古代各种史学、地理、以及宗教文献都有相关记载。早期文献中提出的重源潜流的概念,也为塑造河源空间概念留下了发挥余地。及至唐朝,各种类书、笔记、野史关于位于境外的河源的著述沿用了上述文献中已有的地理知识,并融入了佛教世界观的空间概念以及唐代实地考察的纪录,逐渐构成了河源这一多元化的空间想象。本文探讨了不同知识框架对唐代河源记载的影响,以及在几幅现存宋代地图上所反映出的相关影响。这类文献资料有助于我们理解中古地理知识的深化与演变,以及后代地图上展示河源的更丰富的地图表现形式。     

Gender and returns to promotion: The role of social and power relations

This study extends a theoretical framework of structural resources and vulnerabilities to an examination of individual promotion outcomes. Promotions of 454 individuals to administrative and professional staff positions in one higher education organization are analyzed. The findings confirm that both individual and structural resources are important for explaining the administrative level achieved by promotion in this setting. Although the returns to resouces do not vary by gender, women receive significantly less return to their promotions than men do to theirs. These findings underscore the importance of examining not only individual and structural resources but also the role of gender in the social and power relations that influence the promotion of women and men in organizations.     

Interhousehold Transfers of Goods and Services and Reported Well-Being Among Polish Households

Analyses of data from 600 households in the province of Lubin, Poland, five years after the economic transformation indicated the transfers of goods and services between households to be quite prevalent, with households with high levels of resources giving goods and services and those with low levels of resources receiving goods and services. The receipt of such transfers does not improve the living conditions of the receiving households relative to those who do not receive help; in fact, those receiving help report lower levels of satisfaction than those not receiving assistance.     

Exiting shelter: an epidemiological analysis of barriers and facilitators for families

This study examines the role of individual- and family-level factors in predicting the length of shelter stays for homeless families. Interviews were conducted with all families exiting one of six emergency family shelters in Worcester, Massachusetts, between November 2006, and November 2007. Analyses, using an ordinary least squares regression model, find that families with a positive alcohol or drug screen in the year prior stay 85 days longer than those without a positive screen; families leaving shelter with a housing subsidy stay 66 days longer than those leaving without a subsidy. Demographic factors, education, employment, health, and mental health are not found to predict shelter stay duration. Consistent with prior research, housing resources relate to families' time in shelter; with the exception of a positive substance abuse screen, individual-level problems are not related to their time in shelter. Efforts to expand these resources at the local, state, and national levels are a high priority.     

Load-Oriented Order Release (LOOR) revisited: bringing it back to the state of the art

In the workload control literature, the Load-Oriented Order Release (LOOR) approach has been neglected since its robustness was questioned at the end of the 1990s. This paper revisits LOOR and evaluates whether its performance can be improved in two ways. First, an intermediate pull release mechanism is added to avoid starvation between periodic release events. This mechanism was recently shown to be effective at improving the performance of a state-of-the-art release method known as LUMS COR. Second, an integer linear programming model is used to manage the trade-off between the timing and load balancing functions of order release. The two refinements are assessed using simulations of different shop configurations, which allow us to evaluate robustness. Results demonstrate that the refinements contribute to improving the performance of LOOR such that it can even outperform LUMS COR. Perhaps counter-intuitively, putting more emphasis on load balancing than on the urgency of individual orders is shown to lead to a lower percentage of tardy orders. Overall, the improvements mean that concerns about LOOR’s robustness are no longer valid – it now appears suitable for a wide range of shops found in practice.