Opportunities for woman-initiated HIV prevention methods among female sex workers in southern China

Rapid changes in China over the past two decades have led to significant problems associated with population migration and changing social attitudes, including a growing sex industry and concurrent increases in STIs and HIV. This article reports results of an exploratory study of microbicide acceptability and readiness and current HIV prevention efforts among female sex workers in two rural and one urban town in Hainan and Guangxi Provinces in southern China. The study focused on these women's knowledge and cultural understandings of options for protecting themselves from exposure to STIs and HIV, and the potential viability and acceptability of woman-initiated prevention methods. We report on ethnographic elicitation interviews conducted with women working within informal sex-work establishments (hotels, massage and beauty parlors, roadside restaurants, boarding houses). We discuss implications of these findings for further promotion of woman-initiated prevention methods such as microbicides and female condoms among female sex workers in China.     

Correlates of perceived effectiveness of the Safe Schools/Healthy Students Initiative

A three-level growth-curve model was applied to estimate perceived impact growth trajectories, using multi-year data from project and school surveys on outcome and program implementation collected from 59 sites and approximately 1165 participating schools in the Safe Schools and Healthy Students Initiative. Primary interest is to determine whether and how project-level and school-level correlates affect schools’ perceptions of the Initiative's effectiveness over time when the effects of the pre-grant environmental conditions, grant operations, and near-term outcomes are considered. Coordination and service integration, comprehensive programs and activities for early childhood development, and change in school involvement were found to be significant predictors of school-perceived overall impact when the effect of poverty was considered. Partnership functioning, perceived importance of school resources, and school involvement were found to be significant predictors of school-perceived impact on substance use prevention when the effect of poverty was considered.     

The effect of visualization method on the performance of simulated microsurgery tasks

The operating microscopes may be a significant cause of fatigue and discomfort in surgeons. The need for the microscope to be placed over the operating field forces surgeons to remain at the microscope's eyepieces at an uncomfortable posture for the entirety of the surgery. This study compared the effects on microsurgical task performance for four visualization methods: a monocular microscope, a binocular microscope, a three-dimensional (3D) flat-panel television display and a two-dimensional (2D) flat-panel television display. Eleven subjects each performed two microsurgical tasks and their performance was documented by video camera. The statistical analysis performed indicated utilization of the microscope as a visualization method increased subject performance. No significant difference in performance between the 2D and stereoscopic visualization methods.     

A Minimum Distance Estimation Approach to the Two-Sample Location-Scale Problem

As reported by Kalbfleisch and Prentice (1980), the generalized Wilcoxon test fails to detect a difference between the lifetime distributions of the male and female mice died from Thymic Leukemia. This failure is a result of the test's inability to detect a distributional difference when a location shift and a scale change exist simultaneously. In this article, we propose an estimator based on the minimization of an average distance between two independent quantile processes under a location-scale model. Large sample inference on the proposed estimator, with possible right-censorship, is discussed. The mouse leukemia data are used as an example for illustration purpose.     

治理通货膨胀预期应成为宏观政策关注的新视角

通货膨胀既可以是供求失衡导致的，也可以是货币膨胀导致的。在世界经济迅猛发展的今天，通货膨胀发生发展的机理也存悄然发生着变化，正是这些变化，使得通货膨胀对社会经济的影响已经前置到通货膨胀预期对经济发展的影响。本文以中国经济企稳过程为真实背景，初步探讨通货膨胀预期的负效应及治理的政策路径，尽管存在个案特征，但仍不失为一种分析思路。     

Enduring an Economic Crisis: The Effect of Macroeconomic Shocks on Intragenerational Mobility in Japan

After the burst of its "bubble" economy in 1989, Japan experienced an astonishingly long economic recession whose gravity surpassed any seen in the industrialized world since the 1930s. While this recession is likely to have important consequences on the well-known workplace arrangements and career mobility patterns in that country, systematic analyses of such consequences are nearly absent. This study examines changes in the rates and directions of job mobility in Japan using work history data collected in 2005 from a nationally representative sample of men and women. I find evidence that Japanese firms have largely retained the core elements of the permanent employment system. The norm that stresses men's loyalty to their employers, however, appears to have weakened, resulting in higher voluntary job turnover among male workers. In addition, the gender gap in lifetime mobility processes has narrowed, but not because Japanese women have gained opportunities in the workplace. Rather, economic stagnation has led to greater fluctuations in employment and wages over men's life course, thereby closing the gender gap. Beyond illustrating the changing stratification process in Japan, the findings have general implications for understanding how economic crises impact employment relations, institutional transformations, and social change in advanced industrialized countries.     

HOW WELL DO SELECTION MODELS PERFORM? ASSESSING THE ACURACY OF ART AUCTION PRE-SALE ESTIMATES

Art auction catalogs provide a pre-sale prediction interval for the price each item is expected to fetch. When the owner consigns art work to the auction house, a reserve price is agreed upon, which is not announced to the bidders. If the highest bid does not reach it, the item is brought in. Since only the prices of the sold items are published, analysts only have a biased sample to examine due to the selective sale process. Relying on the published data leads to underestimating the forecast error of the pre-sale estimates. However, we were able to obtain several art auction catalogs with the highest bids for the unsold items as well as those of the sold items. With these data we were able to evaluate the accuracy of the predictions of the sale prices or highest bids for all item obtained from the original Heckman selection model that assumed normal error distributions as well as those derived from an alternative model using the t(2) distribution, which yielded a noticeably better fit to several sets of auction data. The measures of prediction accuracy are of more than academic interest as they are used by auction participants to guide their bidding or selling strategy, and similar appraisals are accepted by the US Internal Revenue Services to justify the deductions for charitable contributions donors make on their tax returns.     

Methodological problems and policy implications in Vietnamese refugee research

This article is written with 2 objectives: 1) to describe some of the critical methodological problems encountered in research with Vietnamese refugees in San Diego, California, about whom few studies have been conducted previous to their arrival in 1975; and 2) to discuss the policy implications of research beset with these difficulties, some of which are unique to studies of refugee populations per se, while others are common to research on small ethnic minorities in general. This article focuses on 4 major issues: 1) the quality of refugee studies, 2) the purpose and functions of such research, 3) the ethical dilemmas of studying refugees, and 4) public policy implications of refugee research. Recommendations are offered to resolve some of these issues which would call for policy changes both in the ways that refugee research is conducted and in the training of researchers themselves.     

Estimating age-specific incidence of dementia using prevalent cohort data

In prospective cohort studies individuals are usually recruited according to a certain cross-sectional sampling criterion. The prevalent cohort is defined as a group of individuals who are alive but possibly with disease at the beginning of the study. It is appealing to incorporate the prevalent cases to estimate the incidence rate of disease before the enrollment. The method of back calculation of incidence rate has been used to estimate the incubation time from HIV infection to AIDS. The time origin is defined as the time of HIV infection. In aging cohort studies, the primary time scale is age of disease onset, subjects have to survive certain years to be enrolled into the study, thus creating left truncation (delay entry). The current methods usually assume that either the disease incidence is rare or the excess mortality due to disease is small compared to the healthy subjects. By far the validity of the results based on these assumptions has not been examined. In this paper, a simple alternative method is proposed to estimate dementia incidence rate before enrollment using prevalent cohort data with left truncation. Furthermore simulations are used to examine the performance of the estimation of disease incidence under different assumptions of disease incidence rates and excess mortality hazards due to disease. As application, the method is applied to the prevalent cases of dementia from the Honolulu Asia Aging Study to estimate dementia incidence rate and to assess the effect of hypertension, Apoe 4 and education on dementia onset.