Marijuana use and depression

The primary goal of this study is to examine the association between marijuana use and adult depressive symptomatology. The key independent variables examined are age of marijuana initiation, frequency of current marijuana use, the use of other licit and illicit drugs, and whether marijuana was used to cope with problems. The relationships among these variables are assessed using data from the Young Men and Drugs Survey (n = 1,941), a nationally representative sample of men from the 1944-1954 birth cohort. Results show that early marijuana initiation appears to be weakly associated with increased depression in adulthood. This effect, however, is mediated by educational attainment, employment status, marital status, and other drug use, notably alcohol and tobacco use. Adult frequency of marijuana use is not significantly associated with increased depression in adulthood. Finally, marijuana users who use the drug to cope with problems are more depressed than those who do not use to cope with problems.     

Policy challenges for child welfare in the new century

Recent changes in public policy reflect increased efforts to scapegoat poor women and children and to polarize the objectives of child protection and family preservation. This article challenges various stakeholders in the child welfare field to move beyond the quick-fix solutions and bureaucratic overregulation precipitated by horror stories of child abuse in the media. The new century presents an opportunity to pursue differential intervention strategies that protect children while empowering poor families and communities.     

Experiments with incentives in telephone surveys

In an effort to counter the problem of noncooperation, survey organizations are offering incentives to respondents with increasing frequency, some at the outset of the survey, as has traditionally been done in mail surveys, and some only after the person has refused, in an attempt to convert the refusal. This article reports on a series of experiments carried out over a period of about 2 years with a monthly telephone survey, the Survey of Consumer Attitudes, in an effort to increase response rates or reduce interviewer effort. We report on experiments with prepaid versus promised incentives; advance letters; and advance letters with prepaid incentives; and we also report on the effects of incentives on response quality, sample composition, response bias, interviewer and respondent expectations, and costs.     

网上交易中诚信交易激励机制设计

网上交易中日益增长的欺诈行为阻碍了人们参与网上交易的积极性.激励参与方在网上交易中诚信交易非常必要,而现有的简单反馈机制难以实现激励诚信交易的功能.提出了一种新的网上交易市场中激励诚信交易的机制——注册押金和交易保证金制度.该机制不仅把交易前的交易保证金与交易方信誉指数结合起来防范交易方欺诈,而且重构了每次交易可获得的信誉指数计算方法以激励交易方在长期中保持诚信.通过对该机制下交易方行为的博弈分析,证明了诚信不仅是单阶段博弈的纳什均衡策略,还是长期博弈的子博弈完美纳什均衡策略.最后,通过随机选取eBay市场的交易数据,对机制进行了模拟,并验证了其有效性.     

An application of multiple objective linear programming to media selection

A multiple objective linear programming (MOLP) method utilizing interval criterion weights is applied to the problem of media selection. Using this technique, it is possible to analyze a problem more explicitly in terms of the several objectives inherent in many media selection situations. In order to illustrate the interval criterion weights approach, a multiple objective hierarchical media selection model is presented and its computer results discussed. In addition to being able to deal more directly with different decision criteria, a distinguishing feature of the mathematical analysis applied here is that its output enables the media-planner to be presented with a small cluster of candidate media schedules (rather than just one). Then, from this list, the media-planner should be in a position to qualitatively make a final choice as a close approximation to his optimal solution.     

A decomposition technique for quantifying real process performance

A decomposition technique for quantifying the impacts of changes in product mix and process performance on aggregate process-related indicators is presented. Through application of the technique, the real performance of a process can be quantified. Changes in real performance over time can be monitored to provide useful information for process evaluation and production planning. Two case studies, one related to the aggregate defective rate for an assembly line of an integrated circuit fabrication plant and the other to the aggregate inventory turnover for a tyre distribution company, are presented to illustrate the application of the technique.     

A generating algorithm for linear trend-free and nearly linear trend-free block designs

The theory and properties of trend-free (TF) and nearly trend-free (NTF) block designs are wel1 developed. Applications have been hampered because a methodology for design construction has not been available.

This article begins with a short review of concepts and properties of TF and NTF block designs. The major contribution is provision of an algorithm for the construction of linear and nearly linear TF block designs. The algorithm is incorporated in a computer program in FORTRAN 77 provided in an appendix for the IBM PC or compatible microcomputer, a program adaptable also to other computers. Three sets of block designs generated by the program are given as examples.

A numerical example of analysis of a linear trend-free balanced incomplete block design is provided.     

EFFECTS OF OVERWEIGHT ON RISKY SEXUAL BEHAVIOR OF ADOLESCENT GIRLS

We use data from the National Longitudinal Survey of Adolescent Health to estimate effects of adolescent girls' overweight on their propensity to engage in risky sexual behavior. We estimate single equation, two‐stage, and sibling fixed‐effects models. We consider both absolute weight and weight relative to other girls in the individual's school. We focus on vaginal intercourse without a condom, any type of sexual activity while under the influence of alcohol, and anal intercourse. Our findings confirm previous research indicating that overweight or obese girls are less likely than their recommended‐weight counterparts to be sexually active. As a result, they are less likely to have vaginal intercourse without a condom. However, overweight or obese girls are not less likely to have sex under the influence of alcohol, and once they have had vaginal intercourse, their consistency of condom use is no different from that of their recommended‐weight peers. The most striking finding is that overweight or obese girls are at least 15% more likely than their recommended‐weight peers to have ever had anal intercourse regardless of whether they have ever had vaginal sexual intercourse. The results from this study underscore the importance of using multifaceted and contemporary measures of risky sexual behavior and have implications for the health and well‐being of adolescent girls. (JEL I12, J13)     

Accounting for unsafe sex: Interviews with men who have sex with men

Semi‐structured one‐on‐one interviews with 102 gay and bisexual men were conducted to examine the reasoning processes men use to exempt themselves from practicing safe sex. Qualitative analysis of the interviews revealed the following recurring themes: (a) Many men who were in couple relationships avoided condom use for reasons involving intimacy or trust, or because both partners were HIV‐negative; (b) unsafe sex sometimes occurred inadvertently or involuntarily; (c) negative moods and self‐images were associated with unsafe sex; (d) by “intuiting” that their partner was HIV‐negative, participants exempted themselves from the need for safe sex; and (e) when the boundary between safe and unsafe was unclear, participants used a combination of unofficial and official guidelines to determine what is safe.