A gender comparison of HIV and drug use across the rural-urban continuum

Despite the central role of women drug users in escalating AIDS statistics, there is still a limited number of studies that examine the roles of gender and drug use type in HIV seroprevalence. This lacuna in the research literature has led to significant gaps in researchers' understanding of how and to what extent women may differ in their drug-using and HIV risk behaviors compared to their better-studied male counterparts. This study, derived from a sample of 3,555 out-of-treatment drug users residing in three South Florida urban and rural communities, attempts to compare the drug usage and needle and sexual risk behaviors of male and female drug users that put them at risk for HIV infection. The overall seropositivity rate for women drug users was 26.5% compared to 19.5% for their male counterparts. Results of multivariate analyses indicate that females compared to males were 1.4 times more likely to be HIV seropositive. Risk behaviors associated with this elevated seropositivity include living arrangements, homeless status, drug use, sexual trading behaviors, and history of STDs. Furthermore, there was a strong linear relationship between drug use type and HIV seroprevalence among women drug users. Compared to those who were neither crack smokers nor injectors of illicit drugs, those who were crack smokers only were 2 times more likely to be HIV seropositive, while those who were both crack smokers and injectors were 5 times more likely to be HIV seropositive, and those who were injectors only were 6 times more likely to be HIV seropositive. These findings indicate that among women, drug abuse and its associated risk behaviors, increase the vulnerability of this population for HIV and thus render them an extremely important priority population on which to focus HIV prevention and public health efforts and programs.     

Nonparametric bootstrapping for hierarchical data

Nonparametric bootstrapping for hierarchical data is relatively underdeveloped and not straightforward: certainly it does not make sense to use simple nonparametric resampling, which treats all observations as independent. We have provided some resampling strategies of hierarchical data, proved that the strategy of nonparametric bootstrapping on the highest level (randomly sampling all other levels without replacement within the highest level selected by randomly sampling the highest levels with replacement) is better than that on lower levels, analyzed real data and performed simulation studies.     

《歧路灯》词语杂释

清代长篇白话小说《歧路灯》，是研究18世纪中原官话的不可多得的语料。由于各种原因，以往学界对它缺乏足够的重视，以至于其中十分丰富的方言俚语都很少有人问津。对该书中“投词”、“信惯”、“撞头撞脑”、“黄金入柜”、“扣”、“开拨”、“嫌择”七个词语加以诠释，对《歧路灯》的语言研究略有裨益。     

Sample Size and Power Calculations for Left-Truncated Normal Distribution

Abstract

Sample size calculation is an important component in designing an experiment or a survey. In a wide variety of fields—including management science, insurance, and biological and medical science—truncated normal distributions are encountered in many applications. However, the sample size required for the left-truncated normal distribution has not been investigated, because the distribution of the sample mean from the left-truncated normal distribution is complex and difficult to obtain. This paper compares an ad hoc approach to two newly proposed methods based on the Central Limit Theorem and on a high degree saddlepoint approximation for calculating the required sample size with the prespecified power. As shown by use of simulations and an example of health insurance cost in China, the ad hoc approach underestimates the sample size required to achieve prespecified power. The method based on the high degree saddlepoint approximation provides valid sample size and power calculations, and it performs better than the Central Limit Theorem. When the sample size is not too small, the Central Limit Theorem also provides a valid, but relatively simple tool to approximate that sample size.     

杨绛小说中的贤妻良母形象

杨绛出于对民族传统文化和人伦道德的尊崇和切身体验 ,在小说中塑造出一批贤妻良母形象 ,着力从她们身上发掘出流传久远的贤良美德 ,并以她们的人性美、人情美 ,映照出周围可笑可讽的的人和事。这些活生生的人物形象不仅能给人以美感和道德启示 ,还填补了文学史上的某些缺憾。