A Comparison of Some Methods for the Selection of a Common Eigenvector Model for the Covariance Matrices of Two Groups

Two new nonparametric common principal component model selection procedures based on bootstrap distributions of the vector correlations of all combinations of the eigenvectors from two groups are proposed. The performance of these methods is compared in a simulation study to the two parametric methods previously suggested by Flury in 1988, as well as modified versions of two nonparametric methods proposed by Klingenberg in 1996 and then by Klingenberg and McIntyre in 1998. The proposed bootstrap vector correlation distribution (BVD) method is shown to outperform all of the existing methods in most of the simulated situations considered.     

Power analysis for clustered non-continuous responses in multicenter trials

Power analysis for multi-center randomized control trials is quite difficult to perform for non-continuous responses when site differences are modeled by random effects using the generalized linear mixed-effects model (GLMM). First, it is not possible to construct power functions analytically, because of the extreme complexity of the sampling distribution of parameter estimates. Second, Monte Carlo (MC) simulation, a popular option for estimating power for complex models, does not work within the current context because of a lack of methods and software packages that would provide reliable estimates for fitting such GLMMs. For example, even statistical packages from software giants like SAS do not provide reliable estimates at the time of writing. Another major limitation of MC simulation is the lengthy running time, especially for complex models such as GLMM, especially when estimating power for multiple scenarios of interest. We present a new approach to address such limitations. The proposed approach defines a marginal model to approximate the GLMM and estimates power without relying on MC simulation. The approach is illustrated with both real and simulated data, with the simulation study demonstrating good performance of the method.     

Matching in sexual experience for married, cohabitating, and dating couples

The present study examined heterosexual romantic partners' number of intercourse partners prior to the initiation of their relationship to determine if a significant positive correlation (matching) occurred between partners, and if this matching was associated with their level of love, satisfaction with, and commitment to the relationship. One hundred and six couples who were dating, cohabitating, or married participated in this study. Results indicated that, with the exception of cohabitating couples, romantic partners showed a significant level of matching in the prior number of intercourse partners. Further, among the married couples, a higher discrepancy between men's and women's number of previous intercourse partners was related to lower levels of love, satisfaction, and commitment in the relationship.     

Male bisexuality and condom use at last sexual encounter: results from a national survey

Relatively little is known about condom use among bisexual men as separate and distinct from exclusively homosexual and heterosexual men. Most previous research on bisexual men has relied on non-probabilistic, high risk samples with limited generalizability. We examined the relationship between male behavioral bisexuality and condom use in the 2002 cycle of the National Survey of Family Growth (NSFG). Bisexually-active men positively differed from heterosexually- and homosexually-active men on every indicator of confounding risk. However, bisexually-active men did not report using condoms less often than other men during their last sexual encounters with males and females. Indeed, with female partners, bisexually-active men reported higher rates of condom use than other men. These relationships remained when all sociodemographic and confounding risk factors were held constant. Our results suggest that caution must be used when making assumptions about condom use in the general population of bisexual men from non-probabilistic samples.     

Differences by gender, ethnicity, and acculturation in the efficacy of the keepin' it REAL model prevention program

This study examined whether the efficacy of keepin' it REAL, a model program for substance use prevention in schools, was moderated by gender, ethnicity, and acculturation. Gender differences in program efficacy may arise through boys' higher risk of drug use, inadequate attention to girls' developmental issues, or cultural factors like polarized gender expectations. Data came from a randomized trial in 35 Phoenix, Arizona, middle schools involving 4,622 mostly Latino 7th graders. Using multi-level mixed models and multiple imputation missing techniques, results for the total sample showed no gender differences in program effects on recent substance use, but the program was more effective in fostering boys' than girls' anti-drug norms. Subgroup analyses demonstrated several more beneficial program effects for boys than girls (less alcohol and cigarette use and stronger anti-drug norms), but only among less acculturated Latinos. There were no gender differences in program effects among more acculturated Latinos, nor among non-Latino whites.     

Self-perception of Gambling Problems among Adolescents Identified as At-risk or Problem Gamblers

The relative influence of perceived familial addictive behaviors and personal gambling behaviors on adolescents' self-perceptions of gambling problems was examined. Students from five high schools in Connecticut (N = 3,886) were surveyed. Of those between the ages of 14 and 17 who scored two or more on the South Oaks Gambling Screen--Revised for Adolescents (n = 532; 72% male; 43% Caucasian), 14.3% reported having a current or past problem with gambling. Wagering larger amounts in a single day, gambling on a daily basis, and perceived presence of a family member with a gambling problem were associated with increased odds of self-perception of a gambling problem. Thus, adolescents who may be less likely to be identified for prevention efforts (due to lack of engagement in high stakes gambling or the real/perceived absence of a problematic gambler in the home) appear less likely to perceive a gambling problem. To advance prevention and treatment strategies, the apparent discrepancy between adolescents' self-perceptions and objective reports of problem gambling behaviors warrants further investigation.     

The Transitional Discharge Model: comparing implementation in Canada and Scotland

Effective discharge planning is needed to facilitate clients' transition from psychiatric hospital wards to community care. Previous studies have shown that client outcomes can be improved by using a Transitional Discharge Model (TDM) that includes peer support and an extension of inpatient-practitioner relationships that are introduced prior to discharge. However, countries vary in many ways that may affect implementation of the model. This article describes some of the similarities and differences related to introducing transitional discharge in two countries: Canada and Scotland. It is important to elucidate facilitators and challenges in implementing the TDM to identify and disseminate strategies to aid implementation. Implications for future implementation of the model are also discussed.     

Do hostile sexual beliefs affect men's perceptions of sexual-interest messages?

This study tested the distorted cognitions component of Hall and Hirschman's (1991) quadripartite model of sexual aggression. Men (N = 107) with and without hostile sexual beliefs viewed erotic slides with a female partner who provided one of four patterns of feedback: clear disinterest, token disinterest, compliant interest, and clear interest. Hostile men reported fewer differences between women, were unresponsive to their partner's perceived embarrassment, and reported a consistent positive mood regardless of her feedback. Conversely, nonhostile men were more responsive to feedback, mirrored the partner's embarrassment, and experienced a less positive mood when she communicated clear disinterest in the erotica. These findings support the distorted cognitions component of the quadripartite model of sexual aggression. The authors also discuss the strengths and limitations of this study's methodology.     

Examining the correlates of engagement and disengagement coping among help-seeking battered women

This study examined several potential correlates of engagement and disengagement coping, including abuse-related factors, socioeconomic and social coping resources, and childhood trauma variables among a sample of battered women (N = 388). Relationship abuse frequency, particularly psychological aggression, and peritraumatic dissociation were the strongest positive predictors of the use of disengagement coping. Social coping resources, including tangible support and appraisals of social support and belonging, were associated with higher engagement coping and lower disengagement coping. A positive association was also found between interparental domestic violence and disengagement coping, and negative associations were found between both childhood physical and sexual abuse and engagement coping. Results suggest that coping strategies used by battered women are multidetermined and deserve further exploration.     

Unplanned sexual activity as a consequence of alcohol use: a prospective study of risk perceptions and alcohol use among college freshmen

OBJECTIVE: The authors' goal was to show how risk perceptions regarding unplanned sexual activity following alcohol use are prospectively related to subsequent alcohol consumption. PARTICIPANTS: Undergraduate students (N = 380) completed questionnaires at 2 time points during their freshman year. METHODS: In the middle of the academic year (T1), students estimated their risk of engaging in unplanned sex and reported their alcohol use during the previous term. Four months later (T2), they again reported alcohol use and indicated whether they had engaged in unplanned sex since T1. RESULTS: Students who consumed more alcohol at T1 rated their risk of unplanned sex more highly, suggesting relative accuracy. Those with higher risk perceptions consumed more alcohol at T2 (controlling for T1 use), suggesting that they maintained the high-risk behavior. Last, those who were unrealistically optimistic (ie, estimated low risk at T1 yet had unplanned sex by T2) reported greater alcohol use at T2. CONCLUSIONS: These findings highlight the role that risk perceptions regarding sexual activity may play in college students' alcohol use.