Handgun carrying among white youth increasing in the United States: new evidence from the national survey on drug use and health 2002–2013

The objective of the present study was to examine trends and correlates of handgun carrying among adolescents ages 12–17 in the United States. Data was derived from the National Survey on Drug Use and Health (NSDUH) involving non-Hispanic White, African American, and Hispanic respondents ages 12–17 (n = 197,313) and spanning the years 2002–2013. Logistic regression was used to examine significance of trend year and correlates of previous 12-month handgun carrying. The overall self-reported prevalence of handgun carrying was 3.4%. The prevalence of handgun carrying during 2004–2005 was significantly higher for African-Americans (4.39%) compared to non-Hispanic Whites (3.03%). However, by 2012–2013, non-Hispanic Whites (4.08%) completely diverged and reported carrying handguns significantly more than both African-American (2.96%) and Hispanic (2.82%) youth. Male gender and a number of externalizing behaviors were significant correlates of handgun carrying; however, we also found evidence of differential correlates with regard to such factors as drug selling, parental affirmation, and income by race/ethnicity. To our knowledge, this is the largest study of handgun carrying among youth in the United States. Findings indicate that although at historically low levels handgun carrying is on the rise but only among non-Hispanic Whites. Differential correlates among racial/ethnic groups suggest prevention programming and policies may need modifications depending on group and geographic locale targeted.R25 DA030310 - National Institute on Drug Abuse at the National Institutes of Healt

Trends and correlates of substance use disorders among probationers and parolees in the United States 2002–2014

BACKGROUND: Substance use and crime/recidivism are irrevocably linked. We explore the nuances of this association by highlighting the prevalence, trends, and correlates of substance use dsorders in a large group of probationers/parolees. METHODS: We examined SUDs among probationers and parolees in the United States using data from the National Study on Drug Use and Health (NSDUH). Logistic regression models were computed to examine eight distinct outcomes: alcohol abuse, illicit drug abuse, marijuana/hashish abuse, comorbid alcohol and illicit drug abuse, alcohol dependence, illicit drug dependence, marijuana/hashish dependence, and comorbid alcohol and illicit drug dependence. RESULTS: Probationers/parolees have high prevalence rates across all SUDs categories and these trends have been relatively constant. Prevalence rates for alcohol abuse and dependence are two to six times higher than for marijuana and other illicit drug abuse and dependence. Key correlates of substance abuse for probationers/parolees include: age, gender, race/ethnicity, education, income, risk propensity, crime/violence measures, and comorbid substance abuse. Similar correlates were found for substance dependence, in addition to employment and mental health treatment. CONCLUSIONS: This study indicates that SUDs are higher among probationer/parolees as compared to their non-supervised counterparts − between four and nine times higher − and these levels have changed little in recent years. Effectively responding to SUDs in this population may enhance adherence to supervision requirements, prevent recidivism, and improve public safety. We may be better served using limited funds for further development of evidence-based policies and programs, such as drug courts, which demonstrate reductions in both drug use and recidivism

Trends and correlates of marijuana use among late middle-aged and older adults in the United States, 2002–2014

BACKGROUND: Recent trend studies suggest that marijuana use is on the rise among the general population of adults ages 18 and older in the United States. However, little is known about the trends in marijuana use and marijuana-specific risk/protective factors among American adults during the latter part of adulthood. METHOD: Findings are based on repeated, cross-sectional data collected from late middle-aged (ages 50–64) and older adults (ages 65 and older) surveyed as part of the National Survey on Drug Use and Health between 2002 and 2014. RESULTS: The prevalence of past-year marijuana use among late middle-aged adults increased significantly from a low of 2.95% in 2003 to a high of 9.08% in 2014. Similarly, the prevalence of marijuana use increased significantly among older adults from a low of 0.15% in 2003 to a high of 2.04% in 2014. Notably, the upward trends in marijuana use remained significant even when accounting for sociodemographic, substance use, behavioral, and health-related factors. We also found that decreases in marijuana-specific protective factors were associated with the observed trend changes in marijuana use among late middle-aged and older adults, and observed a weakening of the association between late-middle aged marijuana use and risk propensity, other illicit drug use, and criminal justice system involvement over the course of the study. CONCLUSIONS: Findings from the present study provide robust evidence indicating that marijuana use among older Americans has increased markedly in recent years, with the most evident changes observed between 2008 and 2014

A flexible and parallelizable approach to genome-wide polygenic risk scores.

The heritability of most complex traits is driven by variants throughout the genome. Consequently, polygenic risk scores, which combine information on multiple variants genome-wide, have demonstrated improved accuracy in genetic risk prediction. We present a new two-step approach to constructing genome-wide polygenic risk scores from meta-GWAS summary statistics. Local linkage disequilibrium (LD) is adjusted for in Step 1, followed by, uniquely, long-range LD in Step 2. Our algorithm is highly parallelizable since block-wise analyses in Step 1 can be distributed across a high-performance computing cluster, and flexible, since sparsity and heritability are estimated within each block. Inference is obtained through a formal Bayesian variable selection framework, meaning final risk predictions are averaged over competing models. We compared our method to two alternative approaches: LDPred and lassosum using all seven traits in the Welcome Trust Case Control Consortium as well as meta-GWAS summaries for type 1 diabetes (T1D), coronary artery disease, and schizophrenia. Performance was generally similar across methods, although our framework provided more accurate predictions for T1D, for which there are multiple heterogeneous signals in regions of both short- and long-range LD. With sufficient compute resources, our method also allows the fastest runtimes

Electronic structure of warm dense copper studied by ultrafast x-ray absorption spectroscopy

We use time-resolved x-ray absorption spectroscopy to investigate the unoccupied electronic density of states of warm dense copper that is produced isochorically through the absorption of an ultrafast optical pulse. The temperature of the superheated electron-hole plasma, which ranges from 4000 to 10 000 K, was determined by comparing the measured x-ray absorption spectrum with a simulation. The electronic structure of warm dense copper is adequately described with the high temperature electronic density of state calculated by the density functional theory. The dynamics of the electron temperature is consistent with a two-temperature model, while a temperature-dependent electron-phonon coupling parameter is necessary