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While many adolescents and young adults experiment with substances (e.g., alcohol, cigarette smoking, marijuana), recent research suggests that rural youth and young adults may be more at risk for substance use than their urban counterparts. This study was designed to examine the longitudinal relationships between rural adolescents' prosocial behaviors and substance use in young adulthood. Furthermore, we examined the potential mediating effects of adolescent substance use, academic investment, and delinquency. Rural youth (N = 531; 263 girls) were surveyed in grades 10-12 (Time 1; M age = 16.17; SD = 0.91) and again in early adulthood (Time 2). Measures of prosocial behaviors, substance use, academic investment, and deviant activities were assessed at Time 1. At Time 2, measures of marijuana use, cigarette smoking, and getting drunk were administered. Overall, the findings showed that rural adolescents who frequently exhibit prosocial behaviors are less likely to engage in substance use in young adulthood than those who exhibit relatively low levels of prosocial behaviors. These findings indicate that prosocial behaviors may have positive health consequences, establishing behavioral trajectories that lead to lower levels of risky health behaviors in adulthood in rural populations.

Context: Disparities in the prevalence, morbidity, and mortality of multiple mental health conditions have been described between rural and urban populations. However, there is limited information regarding differences in exposure to trauma and trauma-related mental health conditions in these populations. Given the number of veterans who are returning to rural communities after serving in Operation Enduring Freedom and Operation Iraqi Freedom, differences in trauma exposure are of particular relevance. Trauma exposure is related to a variety of mental health disorders including substance use disorders (SUD). Purpose: The objectives of this preliminary study were to describe lifetime military and nonmilitary trauma and to compare trauma history between rural and urban veterans in SUD treatment. Methods: Sixty adults in SUD treatment were enrolled at 3 Veterans Health Administration sites in Nebraska over a 3-month period in 2008. Subjects completed an interview with study staff, which assessed SUD diagnoses and childhood, lifetime, and military trauma. Rural or urban status was determined by self-report of childhood residence. Childhood trauma, lifetime trauma, and response to military trauma were compared between rural and urban veterans. Findings: Although there were no significant differences in trauma exposure between rural and urban groups, there was an association between specific types of trauma and measures typically associated with increased substance abuse severity and poorer SUD treatment outcome. Conclusion: This is the first study, to our knowledge, which compared trauma exposure between rural and urban veterans and identified an association between childhood trauma exposure and multiple SUD treatment attempts.

Environmental familiarization is a learning phenomenon embedded within most tasks used to study learning and motivation. Given its prevalence there is surprisingly little systematic behavioral research on factors affecting familiarization. The six experiments reported in the present report used rats' tendency to interact more with a novel object in a familiar than in a novel environment as a measure of environmental familiarization. We found that 3 min of exposure to the environment was sufficient to increase object interaction above unfamiliar controls even when testing occurred up to 48 h after initial exposure to the environment; 1- or 1.5-min of exposure was not sufficient. Also, in the brief 2 min test, 10 min of environment exposure did not appear to increase object interaction above the 3-min condition. The 3-min of environment exposure was sufficient for familiarization whether environment exposure occurred in one 3 min placement or two 1.5 min placements. Environmental familiarization as measured by object interaction was also sensitive to "interference" manipulations. That is, a distinct object present during initial exposure to the environment produced a level of object interaction in testing comparable to an unfamiliar control. Similarly, exposure to a second distinct alternate environment immediately "after", but not "before", initial exposure to the test environment partially disrupted environmental familiarization. In sum, object interaction might serve as a useful measure for studying processes mediating environmental familiarity.

Colloform textures have been described from many of the world's sulphide ore deposits and involve formation of distinct microcrystalline layers. These textures provide information related to sequential stages of ore formation, yet their mechanism of growth is poorly understood. This study has analysed a series of colloform samples from the Galmoy Zn + Pb mine, Ireland. Results indicate that the growth sequence is not always intuitive and layers that appear stratigraphic upon cursory observation may not be. The crystal preferred orientation (CPO) of discrete colloform layers abruptly switches between different orientation axes. Examination of the same layers using in situ laser sulphur isotope analysis reveals equally striking changes in [delta][sup.34]S signature between end-member bacteriogenic (-25[per thousand]) and hydrothermal (+10[per thousand]) sources. Although these results, combined with petrographic observation, allow the determination of a probable growth history, there is no correlation between shifting CPO and [delta][sup.34]S signature. Trace element analysis reveals changes in trace element sequestration between colloform layers. Cadmium- and chlorine-rich layers correspond to a hydrothermal sulphur source, whereas iron-rich layers correspond to a bacteriogenic sulphur source. In the absence of alternative mechanisms we suggest that the most likely factors influencing CPO changes are temperature and degree of supersaturation during two-fluid mixing.