Genetics of pathological gambling

Pathological gambling (PG) is an impulse control disorder and a model behavioral addiction. Familial factors have been observed in clinical studies of pathological gamblers, and twin studies have demonstrated a genetic influence contributing to the development of PG. Serotonergic, noradrenergic, and dopaminergic dysfunction have been reported as biological factors contributing to the pathophysiology of PG. Molecular genetic techniques have been used to investigate the role of genetic factors in PG. Molecular genetic research has identified specific allele variants of candidate genes corresponding to these neurotransmitter systems to be associated with PG. Associations have been reported between pathological gamblers and allele variants of polymorphisms at dopamine receptor genes, the serotonin transporter gene, and the monoamine-oxidase A gene. Although preliminary data suggest that some of these differences are gender-specific, more research needs to be performed to substantiate gender-specific genetic contributions to the development of pathological gambling. The review of the current findings on genetics of PG suggests that liability to PG is in part mediated by genetic factors. Additional studies are needed to replicate and extend these findings, as well as to better understand the influence of specific allelic variants to differences in biological and behavioral functioning.     

Sexual Compulsivity and Sexual Behaviors Among Gay and Bisexual Men and Lesbian and Bisexual Women

Within the existing body of research, the information pertaining to sexual compulsivity (SC) among women, both homo- and heterosexual, remains rather limited in comparison to men. The aim of this study was to assess the prevalence of SC in a community sample of gay and bisexual men and lesbian and bisexual women and to identify differences in sexual practices based on classification as sexually compulsive within gender. Supporting previous research, the findings indicated that gay and bisexual men were significantly higher in SC when compared to lesbian and bisexual women. Similarly, sexually compulsive gay and bisexual men were more likely to report drug use with sex than their non-sexually compulsive peers, suggesting that “party n' play” may play a larger role for men with SC. In addition, the findings demonstrated empirical support for the proposition that lesbian and bisexual women with symptoms of SC were more likely to engage in specialized sexual behaviors in comparison to their non-sexually compulsive peers. These data suggest that SC manifests differently in gay, lesbian, and bisexual men and women.     

A weak convergence criterion for constructing changes of measure

Based on a weak convergence argument, we provide a necessary and sufficient condition that guarantees that a nonnegative local martingale is indeed a martingale. Typically, conditions of this sort are expressed in terms of integrability conditions (such as the well-known Novikov condition). The weak convergence approach that we propose allows to replace integrability conditions by a suitable tightness condition. We then provide several applications of this approach ranging from simplified proofs of classical results to characterizations of processes conditioned on first passage time events and changes of measures for jump processes.     

Exact optimal experimental designs with constraints

The experimental design literature has produced a wide range of algorithms optimizing estimator variance for linear models where the design-space is finite or a convex polytope. But these methods have problems handling nonlinear constraints or constraints over multiple treatments. This paper presents Newton-type algorithms to compute exact optimal designs in models with continuous and/or discrete regressors, where the set of feasible treatments is defined by nonlinear constraints. We carry out numerical comparisons with other state-of-art methods to show the performance of this approach.