THE INITIAL ASSESSMENT OF A COMMUNITY-BASED INTERVENTION WITH MEXICAN-HERITAGE PARENTS IN BOOSTING THE EFFECTS OF A SUBSTANCE USE PREVENTION INTERVENTION WITH YOUTH.

Drawing from an ecodevelopmental framework, this article examines if adding a parenting component, Families Preparing the New Generation (Familias Preparando la Nueva Generación), to an efficacious classroom-based drug abuse prevention intervention, keepin'it REAL, will boost the effects of the youth intervention in preventing substance use for middle school Mexican-heritage students. Youth attending schools in a large urban area in the Southwestern U.S. (N = 462) were randomly assigned to 1 of 3 conditions: parent and youth, youth only, or control. Using ordinary least squares regression, changes in youth substance use outcomes were examined. Results indicate that youth whose parents also participated in prevention programming exhibited significantly lower use of alcohol, cigarettes, marijuana, and inhalants compared to youth who received only keepin'it REAL. These initial effects indicate that involving parents in prevention efforts can strengthen the overall efficacy of a youth prevention intervention. This article discusses specific implications for the design of prevention interventions, policy, and future research.

Drosophila increase exploration after visually detecting predators.

Novel stimuli elicit behaviors that are collectively known as specific exploration. These behaviors allow the animal to become more familiar with the novel objects within its environment. Specific exploration is frequently suppressed by defensive reactions to predator cues. Herein, we examine if this suppression occurs in Drosophila melanogaster by measuring the response of these flies to wild harvested predators. The flies used in our experiments have been cultured and had not lived under predator threat for multiple decades. In a circular arena with centrally-caged predators, wild type Drosophila actively avoided the pantropical jumping spider, Plexippus paykulli, and the Texas unicorn mantis, Phyllovates chlorophaena, indicating an innate defensive reaction to these predators. Interestingly, wild type Drosophila males also avoided a centrally-caged mock spider, and the avoidance of the mock spider became exaggerated when it was made to move within the cage. Visually impaired Drosophila failed to detect and avoid the Plexippus paykulli and the moving mock spider, while the broadly anosmic orco2 mutants were fully capable of detecting and avoiding Plexippus paykulli, indicating that these flies principally relied upon vison to perceive the predator stimuli. During early exploration of the arena, exploratory activity increased in the presence of Plexippus paykulli and the moving mock spider. The elevated activity induced by Plexippus paykulli disappeared after the fly had finished exploring, suggesting the flies were capable of habituating the predator cues. Taken together, these results indicate that despite being isolated from predators for decades Drosophila will visually detect these predators, retain innate defensive behaviors, respond by increasing exploratory activity in the arena rather than suppressing activity, and may habituate to normal predator cues.

Testing the hypothesis that treatment can eliminate HIV: a nationwide, population-based study of the Danish HIV epidemic in men who have sex with men.

BACKGROUND: Worldwide, approximately 35 million individuals are infected with HIV; about 25 million of these live in sub-Saharan Africa. WHO proposes using treatment as prevention (TasP) to eliminate HIV. Treatment suppresses viral load, decreasing the probability an individual transmits HIV. The elimination threshold is one new HIV infection per 1000 individuals. Here, we test the hypothesis that TasP can substantially reduce epidemics and eliminate HIV. We estimate the impact of TasP, between 1996 and 2013, on the Danish HIV epidemic in men who have sex with men (MSM), an epidemic UNAIDS has identified as a priority for elimination. METHODS: We use a CD4-staged Bayesian back-calculation approach to estimate incidence, and the hidden epidemic (the number of HIV-infected undiagnosed MSM). To develop the back-calculation model, we use data from an ongoing nationwide population-based study: the Danish HIV Cohort Study. FINDINGS: Incidence, and the hidden epidemic, decreased substantially after treatment was introduced in 1996. By 2013, incidence was close to the elimination threshold: 1·4 (median, 95% Bayesian credible interval [BCI] 0·4-2·1) new HIV infections per 1000 MSM and there were only 617 (264-858) undiagnosed MSM. Decreasing incidence and increasing treatment coverage were highly correlated; a treatment threshold effect was apparent. INTERPRETATION: Our study is the first to show that TasP can substantially reduce a country's HIV epidemic, and bring it close to elimination. However, we have shown the effectiveness of TasP under optimal conditions: very high treatment coverage, and exceptionally high (98%) viral suppression rate. Unless these extremely challenging conditions can be met in sub-Saharan Africa, the WHO's global elimination strategy is unlikely to succeed. FUNDING: National Institute of Allergy and Infectious Diseases.

A latent class analysis of urban American Indian youth identities.

OBJECTIVE: This study examined sources of indigenous identity among urban American Indian youth that map the three theoretical dimensions of a model advanced by Markstrom: identification (tribal and ethnic heritage), connection (through family and reservation ties), and involvement in traditional culture and spirituality. METHOD: Data came from self-administered questionnaires completed by 208 urban American Indian students from five middle schools in a large metropolitan area in the Southwest. RESULTS: Descriptive statistics showed most youth were connected to multiple indicators on all three dimensions of indigenous identity: native parental heritage, native best friends, past and current reservation connections, involvement with cultural practices, tribal language and spirituality, and alignment with native and mainstream cultural orientations. A latent class analysis identified five classes. There were two larger groups, one with strong native heritage and the highest levels of enculturation, and another that was more bicultural in orientation. The remaining three groups were smaller and about equal in size: a highly acculturated group with mixed parental ethnic heritage, those who had strong native heritage but were culturally disengaged, and a group with some mixed ethnic heritage that was low on indicators of enculturation. Evidence for the validity of the latent classes came from significant variations across the classes in scores on an American Indian ethnic identity (modified Phinney) scale, the students' open-ended descriptions of the main sources of their indigenous identities, and the better academic grades of classes that were more culturally engaged. CONCLUSIONS: Despite the challenges of maintaining cultural identities in the urban environment, most youth in this sample expressed a strong sense of indigenous identity, claimed personal and parental tribal heritage, remained connected to reservation communities, and actively engaged in Native cultural and spiritual life.

Long-term effects of the keepin' it REAL model program in Mexico: substance use trajectories of Guadalajara middle school students.

In the face of rising rates of substance use among Mexican youth and rapidly narrowing gender differences in use, substance use prevention is an increasingly urgent priority for Mexico. Prevention interventions have been implemented in Mexico but few have been rigorously evaluated for effectiveness. This article presents the long term effects of a Mexico-based pilot study to test the feasibility of a linguistically specific (Mexican Spanish) adapted version of keepin' it REAL, a school-based substance abuse prevention model program. University affiliated researchers from Mexico and the US collaborated on the study design, program implementation, data collection, and analysis. Students and their teachers from two middle schools (secundarias) in Guadalajara participated in this field trial of Mantente REAL (translated to Spanish). The schools were randomly assigned to treatment and control conditions. The sample of 431 students reported last 30 day substance use at three times (one pretest and two posttests). Changes in substance use behaviors over time were examined using growth curve models. Long term desired intervention effects were found for alcohol and marijuana use but not for cigarettes. The intervention effects were greater for girls than for boys in slowing the typical developmental increase over time in alcohol use. Marijuana effects were based on small numbers of users and indicate a need for larger scale studies. These findings suggest that keepin' it REAL is a promising foundation for cultural program adaptation efforts to create efficacious school-based universal prevention interventions for middle school students in Mexico.

Theoretical foundations for traditional and generalized sensitivity functions for nonlinear delay differential equations.

In this paper we present new results for differentiability of delay systems with respect to initial conditions and delays. After motivating our results with a wide range of delay examples arising in biology applications, we further note the need for sensitivity functions (both traditional and generalized sensitivity functions), especially in control and estimation problems. We summarize general existence and uniqueness results before turning to our main results on differentiation with respect to delays, etc. Finally we discuss use of our results in the context of estimation problems.

Standard Error Computations for Uncertainty Quantification in Inverse Problems: Asymptotic Theory vs. Bootstrapping.

We computationally investigate two approaches for uncertainty quantification in inverse problems for nonlinear parameter dependent dynamical systems. We compare the bootstrapping and asymptotic theory approaches for problems involving data with several noise forms and levels. We consider both constant variance absolute error data and relative error which produces non-constant variance data in our parameter estimation formulations. We compare and contrast parameter estimates, standard errors, confidence intervals, and computational times for both bootstrapping and asymptotic theory methods.

High throughput screening for cyanovirin-N mimetics binding to HIV-1 gp41.

The human immunodeficiency virus type-1 (HIV-1) envelope glycoprotein gp41 is an important mediator of viral entry into host cells. Previous studies showed that the virucidal protein cyanovirin-N (CV-N) bound to both gp120 and gp41, and that this binding was associated with its antiviral activity. We constructed an HTS assay based on the interaction of europium-labeled CV-N with recombinant glycosylated gp41 ectodomain to support identification of small-molecule mimetics of CV-N that might be developed as antiviral drug leads. Primary screening of over 107,000 natural product extracts in the assay yielded 347 confirmed hits. Secondary assays eliminated extracts that bound directly to labeled CV-N or for which the simple sugars mannose and N-acetylglucosamine blocked the interaction with gp41 (lectin activity). Extracts were further prioritized based on anti-HIV activity and other biological, biochemical, and chemical criteria. The distribution of source organism taxonomy of active extracts was analyzed, as was the cross-correlation of activity between the CV-N-gp41 binding competition assay and the previously reported CV-N-gp120 binding competition assay. A limited set of extracts was selected for bioassay-guided fractionation.