A Characterization of a Matric-Variate Exponential Distribution

Suppose S is a positive definite m x m random matrix and S> Ω denotes the event that S—Ω is positive definite, Ω being a constant positive definite matrix. Under very mild regularity conditions, we show that the constraint Pr(S>Ω₁+Ω₂ | S>Ω₂) = Pr(S>Ω₁) implies that S has a Wishart distribution on m+ 1 degrees of freedom.     

Industrialization and Social Stratification*

This paper reviews the current state of knowledge about the effects of industrialization upon systems of social stratification. Taking societies as the unit of observation, we consider the relationships between level of industrialization and (1) the distribution of status characteristics in the population (the structure of stratification); (2) the pattern of interrelations among status characteristics (the process of stratification); and (3) the form of linkages between status characteristics and other aspects of social behavior (the consequences of stratification). A set of propositions is specified, a few of which are empirically well established but most of which yet require empirical testing.     

An integrative intervention for promoting recovery from extramarital affairs

The discovery or disclosure of an extramarital affair can have a devastating impact on partners, both individually and on the relationships. Research suggests that affairs occur relatively frequently in relationships and are a common presenting problem in couple therapy. However, despite their prevalence, there is little empirical treatment research in this area, and most therapists describe this problem as one of the more difficult to treat. In this study, we used a replicated case-study design to explore the efficacy of an integrative treatment designed to help couples recover from an affair. Six couples entered and completed treatment. The majority of these couples were less emotionally or maritally distressed at the end of treatment, and the injured partners reported greater forgiveness regarding the affair. Details of the intervention, suggested adaptations of the treatment, and areas for future research are discussed.     

Gender and racial/ethnic differences in predicting adolescent sexual risk: athletic participation versus exercise

Though often conflated, informal physical exercise and organized athletic participation have very different implications for adolescent sexual risk outcomes. The purpose of this research is to disaggregate strenuous exercise from sports, examine how each is associated with sexual risk, and explain the observed differences using the conceptual lens of cultural resource theory. Using a nationally representative sample of over 16,000 public and private high school students, we employ logistic regression to test hypotheses about the gender-specific and race-specific effects of strenuous exercise and athletic participation on adolescent sexual risk behavior. The results show that both forms of physical activity buffer sexual risk for girls. Strenuous exercise is associated with increased odds of sexual risk for boys. Sports and race interact to influence boys' sexual risk outcomes: Athletic participation is associated with lowered odds of sexual risk for white male adolescents, but heightened odds of sexual risk for black male adolescents.     

Reports of childhood sexual abuse by adolescents and young adults: stability over time

The consistency of childhood sexual abuse (CSA) reporting was explored in this study. Two-hundred seventeen adolescents and young adults (ages 14-24) enrolled in urban health care clinics completed self-report questionnaires assessing CSA and other problem behaviors at enrollment and at 7 months. Results indicated that the stability of CSA self-report at two time points was poor (58% consistent nonreporters of CSA, 20% consistent reporters, 22% inconsistent reporters). Consistent and inconsistent reporters were differentiated on risk measures. Adolescents who endorsed more items from the CSA scale were five times more likely to be consistent reporters. In sum, adolescent CSA reporting was quite inconsistent over time. Using multi-item scales and assessing CSA at two time points enhances accuracy of reporting.     

An analysis of VDT monitor placement and daily hours of use for female bifocal users

A population of 72 bifocal wearers was studied to determine the relationship between VDT (video display terminal) placement for those who reported musculoskeletal pain and those who did not. The mean hours worked was 50.4 minutes (p=0.003) greater for those who reported head/neck pain versus those who did not and 48.6 minutes (p=0.004) greater for those who reported shoulder/arm pain that those who did not. There was no statistically significant difference between the means of monitor height, distance, or angle for those who reported pain symptoms versus those who did not. This study indicates that, self reported pain symptoms are correlated with hours of VDT work and that there appears to be a threshold at approximately five hours for pain symptoms among bifocal wearers. No such correlation can be made for monitor placement     

The value of information concept applied to data systems

Cost-benefit analysis has a considerable literature in which information systems have been patently ignored. This reflects the considerable difficulties of applying the theory to information systems, and the state-of-the art remains relatively as Koopmans described it some 19 years ago (1957). A bar to further development would appear to be the lack of an applicable value-of-information concept. This paper seeks to clarify the issues and provide a robust theoretical and data analysis framework that will cover most situations. The approach here is to separate explicitly the dimensions of cost from those of information benefit, and examine the implications. The Null Information Benefit condition emerges as a special theoretical case, but potentially a most important one in applications. This case together with the Pareto optimum defines a large class of such problems that can be handled by the decision criteria and data analysis techniques tabulated and discussed here. The selection of input data techniques defines the limits of later project justification and may be crucial to the political viability of the projects throughout its life. Finally, the general management vs information systems management relationships are discussed in terms of this situation.