A feasibility approach for constructing combinatorial designs of circulant type

In this work, we propose an optimization approach for constructing various classes of circulant combinatorial designs that can be defined in terms of autocorrelation. The problem is formulated as a so-called feasibility problem having three sets, to which the Douglas–Rachford projection algorithm is applied. The approach is illustrated on three different classes of circulant combinatorial designs: circulant weighing matrices, D-optimal matrices of circulant type, and Hadamard matrices with two circulant cores. Furthermore, we explicitly construct two new circulant weighing matrices, a CW(126, 64) and a CW(198, 100), whose existence was previously marked as unresolved in the most recent version of Strassler’s table.     

Contract design and insurance fraud: an experimental investigation

This paper experimentally examines the impact of contract design on insurance fraud. We test how fraud behavior varies for insurance contracts with full coverage, a straight deductible or claim-dependent premiums (bonus-malus contracts), in a setup where rational and selfish individuals have an incentive to always claim the maximum possible indemnity. We find a substantial impact of contractual arrangements: Deductible contracts lead to a greater extent to claim build-up than full coverage contracts. In contrast, bonus-malus contracts that entail the same net gains from fraud as deductible contracts do not increase claim build-up. Thus, our results indicate that bonus-malus contracts may be superior to deductible contracts for behavioral reasons.     

Probabilistic population projections for countries with generalized HIV/AIDS epidemics

In 2015, the United Nations (UN) issued probabilistic population projections for all countries up to 2100, by simulating future levels of total fertility and life expectancy and combining the results using a standard cohort component projection method. For the 40 countries with generalized HIV/AIDS epidemics, the mortality projections used the Spectrum/Estimation and Projection Package (EPP) model, a complex, multistate model designed for short-term projections of policy-relevant quantities for the epidemic. We propose a simpler approach that is more compatible with existing UN projection methods for other countries. Changes in life expectancy are projected probabilistically using a simple time series regression and then converted to age- and sex-specific mortality rates using model life tables designed for countries with HIV/AIDS epidemics. These are then input to the cohort component method, as for other countries. The method performed well in an out-of-sample cross-validation experiment. It gives similar short-run projections to Spectrum/EPP, while being simpler and avoiding multistate modelling.     

Cohort Differences in Parental Financial Help to Adult Children

In this article, we examine birth cohort differences in parents’ provision of monetary help to adult children with particular focus on the extent to which cohort differences in family structure and the transition to adulthood influence these changes. Using data from the Health and Retirement Study from 1994 to 2010, we compare financial help to children of three respondent cohorts as the parents in these birth cohorts from ages 53–58 to 57–62. We find that transfers to children have increased among more recent cohorts. Two trends—declining family size and children’s delay in marriage—account for part of the increase across cohorts. However, other trends, such as the increase in the number of stepchildren and increasing child’s income level, tend to decrease the observed cohort trend.     

Changing land tenure patterns in Scotland: A time for reform?

Land tenure patterns throughout Britain have changed significantly. The popularity of the traditional agricultural tenancy has declined and in response to legislative and policy developments landowners have become reluctant to enter into long-term tenancy arangements with tenants. The result has been a growth in a number of short term leases. In response, legislative reform took place in England and Wales during 1995 and introduced a farm business tenancy. It provides for greater freedom to negotiate individual agreements. However, Scotland has been excluded. This paper illustrates that Scotland has experienced similar changes to those observed elsewhere and that the main short term lease (limited partnership tenancy) currently popular with Scottish landowners is fraught with legal and administrative difficulties. The limited partnership tenancy is not a suitable alternative to the traditional agricultural tenancy and as such there may be a case for the extension of the farm business tenancy to Scotland.     

Exercise self-regulation among older women participating in a heart disease-management intervention

Using behavioral self-regulation processes may facilitate exercise among older women with heart disease. Data from women in a heart disease-management program (n = 658, mean 73 years), was used to explore associations among exercise self-regulation components (i.e., choosing to improve exercise and observing, judging, and reacting to one's behavior) and exercise capacity. General linear models showed that choosing exercise predicted higher exercise self-regulation scores postprogram and 8 months later. In turn, these scores predicted greater improvements in exercise capacity concurrently and 8 months later. Interaction analyses revealed that the effect of self-regulation on exercise capacity was stronger among women who chose to work on exercise.     

Research-in-Progress Sessions Create a More Inclusive and Engaging Regional Conference

The Pacific Sociological Association annual meeting recently added a new session type called the Research-in-Progress (RIP) session. The purpose of adding these sessions was to provide an opportunity for attendees to present research still in formative stages of completion in order to get useful feedback. Presentations ranged from doctoral dissertation proposals to nearly completed research. Early experience from RIP session organizers and discussants is that these sessions were lively and engaging, sparking a great deal of audience participation. Feedback from presenters indicated that they received useful feedback. Based on our initial experience with the RIP sessions, we believe they are a beneficial addition to the meetings.     

Anabolic-Androgenic Steroids and Condom Use: Potential Mechanisms in Adolescent Males

Previous research has revealed a significant bivariate relationship between anabolic-androgenic steroid (AAS) use and reduced condom use among adolescent boys. However, to date, no known studies have explored the psychological mechanisms that may explain this relationship. Thus, the current study sought to examine two possible mediators in the association between AAS and condom use: depressive symptoms and substance use. Data were extracted from a nationally representative sample of U.S. adolescents. Participants were 3,780 U.S. high school boys who responded to self-report items assessing a number of health behaviors, including symptoms of depression, substance use, AAS use, and use of condoms during their most recent act of intercourse. Both depression and substance use were significant mediators in the relationship between AAS and condom use. However, when these effects were contrasted, the indirect effect of substance use was significantly stronger in magnitude than the effect of depression. Although AAS use was associated with sexual risk behaviors among adolescent boys, significant variance in this relationship was accounted for by elevated levels of depression and substance use, with substance use demonstrating a particularly salient pathway.     

Risky Business: Is There an Association between Casual Sex and Mental Health among Emerging Adults?

A multiethnic sample of single, heterosexual, emerging-adult college students (N = 3,907) ages 18 to 25, from 30 institutions across the United States, participated in a study about identity, culture, psychological well-being, and risky behaviors. Given ongoing debates about the connection between casual sex and psychological adjustment, in the current study we assessed the cross-sectional association of participation in casual sex with psychological well-being and distress. A greater proportion of men (18.6%) compared to women (7.4%) reported having had casual sex in the month prior to assessment. Structural equation modeling indicated that casual sex was negatively associated with well-being (ß = .20, p < .001) and positively associated with psychological distress (ß = .16, p < .001). Gender did not moderate these associations. For emerging-adult college students, engaging in casual sex may elevate risk for negative psychological outcomes.