Improving Treatment Through Research Directing Attention to the Role of Development in Adolescent Treatment Success

Treatment of adolescents with alcohol use problems can be as successful as in adults, but the success often is short-lived, with most treated adolescents relapsing within a few months. Developmental differences among adolescents may contribute to this high rate of relapse, and treatment approaches that pay direct attention to the patients’ developmental status may improve outcomes. To date, studies assessing adolescent alcohol treatment rarely have investigated the association between developmental stage and outcome. In addition, even experts do not fully agree on the developmentally appropriate outcomes that should be evaluated in adolescent treatment studies. Research methods and variables used to assess the outcome of adolescent alcohol treatment often rely on those used in treatment studies of adults. Developmental factors that may directly influence adolescents’ amenability to treatment, such as pubertal status, psychological development (e.g., executive mental functions), social relationships, and developmental transitions, have not been adequately investigated. Studies using concepts from developmental science are needed to determine how individual characteristics, various contextual influences (e.g., from peers, family, or the social environment), and the interactions of these factors influence alcohol use behavior, amenability to treatment, and treatment outcomes. Knowledge gained in studies directly examining developmental factors should help in the design of more effective treatment programs with lower relapse rates

Colloidal diffusion and hydrodynamic screening near boundaries

The hydrodynamic interactions between colloidal particles in small ensembles are measured at varying distances from a no-slip surface over a range of inter-particle separations. The diffusion tensor for motion parallel to the wall of each ensemble is calculated by analyzing thousands of particle trajectories generated by blinking holographic optical tweezers and by dynamic simulation. The Stokesian Dynamics simulations predict similar particle dynamics. By separating the dynamics into three classes of modes: self, relative and collective diffusion, we observe qualitatively different behavior depending on the relative magnitudes of the distance of the ensemble from the wall and the inter-particle separation. A simple picture of the pair-hydrodynamic interactions is developed, while many-body-hydrodynamic interactions give rise to more complicated behavior. The results demonstrate that the effect of many-body hydrodynamic interactions in the presence of a wall is much richer than the single particle behavior and that the multiple-particle behavior cannot be simply predicted by a superposition of pair interactions

An Extended Theoretical Framework for the Concept of the Derivative

This paper extends the theoretical framework for exploring student understanding of the concept of the derivative, which was developed by Zandieh (2000). We expand upon the con-cept of a physical representation for the derivative by extending Zandieh’s map of the territory to provide higher resolution in regions that are of interest to those operating in a physical context. We also introduce the idea of ”thick ” derivatives, which are ratios of small but not infinitesimal changes, which are practically equivalent to the true derivative. Key words: derivative, theoretical framework, physical, experiment In this theoretical report we extend the theoretical framework for exploring student understand-ing of the concept of the derivative which was developed by Zandieh (2000). We expand upon the concept of a physical representation for the derivative. As with Zandieh’s original framework, this work is not meant to explain how or why students learn as they do, nor to propose a learning trajectory. Rather, this work extends Zandieh’s map of the territory, to provide higher resolution in regions that are of interest to those working with derivatives in a physical context. In addition to focusing on the physical context, we discuss challenges that have arisen in applying Zandieh’

Abuse Experiences in a Community Sample of Young Adults: Relations With Psychiatric Disorders, Sexual Risk Behaviors, and Sexually Transmitted Diseases

This study documents significant associations among lifetime abuse experiences, psychiatric diagnoses, and sexual risk behaviors in a multiethnic community sample of young men and women (N = 1803) in South Florida. Self-report data were collected via structured interviews as part of a longitudinal follow-up of a larger school-based study. Participants were grouped according to extent of lifetime abuse experiences. Cumulative lifetime abuse experiences were associated with increased risk for a broad range of individual lifetime psychiatric disorders, as well as cumulative lifetime psychiatric disorders. Both cumulative abuse experiences and cumulative psychiatric disorders were independently associated with (a) higher levels of sexual risk behaviors and (b) higher risk for lifetime sexually transmitted diseases (STDs). Implications for selective prevention of sexual risk behaviors and STDs among young adults with histories of abuse and psychiatric disorders are discussed

A new population of recently quenched elliptical galaxies in the SDSS

We use the Sloan Digital Sky Survey to investigate the properties of massive elliptical galaxies in the local Universe (z\leq0.08) that have unusually blue optical colors. Through careful inspection, we distinguish elliptical from non-elliptical morphologies among a large sample of similarly blue galaxies with high central light concentrations (c_r\geq2.6). These blue ellipticals comprise 3.7 per cent of all c_r\geq2.6 galaxies with stellar masses between 10^10 and 10^11 h^{-2} {\rm M}_{\sun}. Using published fiber spectra diagnostics, we identify a unique subset of 172 non-star-forming ellipticals with distinctly blue urz colors and young (< 3 Gyr) light-weighted stellar ages. These recently quenched ellipticals (RQEs) have a number density of 2.7-4.7\times 10^{-5}\,h^3\,{\rm Mpc}^{-3} and sufficient numbers above 2.5\times10^{10} h^{-2} {\rm M}_{\sun} to account for more than half of the expected quiescent growth at late cosmic time assuming this phase lasts 0.5 Gyr. RQEs have properties that are consistent with a recent merger origin (i.e., they are strong `first-generation' elliptical candidates), yet few involved a starburst strong enough to produce an E+A signature. The preferred environment of RQEs (90 per cent reside at the centers of < 3\times 10^{12}\,h^{-1}{\rm M}_{\sun} groups) agrees well with the `small group scale' predicted for maximally efficient spiral merging onto their halo center and rules out satellite-specific quenching processes. The high incidence of Seyfert and LINER activity in RQEs and their plausible descendents may heat the atmospheres of small host halos sufficiently to maintain quenching.Comment: 26 pages, 9 figures. Revised version; accepted for publication in MNRA

Massive stars at low metallicity: Evolution and surface abundances of O dwarfs in the SMC

We study the evolution, rotation, and surface abundances of O-type dwarfs in the Small Magellanic Cloud. We analyzed the UV and optical spectra of twenty-three objects and derived photospheric and wind properties. The observed binary fraction of the sample is ~ 26%, which is compatible with more systematic studies, if one considers that the actual binary fraction is potentially larger owing to low-luminosity companions and that the sample excluded obvious spectroscopic binaries. The location of the fastest rotators in the H-R diagram indicates that these could be several Myr old. The offset in the position of these fast rotators compared with the other stars confirms the predictions of evolutionary models that fast-rotating stars tend to evolve more vertically in the H-R diagram. Only one star of luminosity-class Vz, expected to best characterize extreme youth, is located on the ZAMS, the other two stars are more evolved. The distribution of nitrogen abundance of O and B stars suggests that the mechanisms responsible for the chemical enrichment of slowly rotating massive stars depends only weakly on the star's mass. We confirm that the group of slowly rotating N-rich stars is not reproduced by the evolutionary tracks. Our results call for stronger mixing in the models to explain the range of observed N abundances. All stars have an N/C ratio as a function of stellar luminosity that matches the predictions of the stellar evolution models well. More massive stars have a higher N/C ratio than the less massive stars. Faster rotators show on average a higher N/C ratio than slower rotators. The N/O versus N/C ratios agree qualitatively well with those of stellar evolution models. The only discrepant behavior is observed for the youngest two stars of the sample, which both show very strong signs of mixing, which is unexpected for their evolutionary status.Comment: Accepted for publication in A&A (43 pages, 60 figures

Metabolism and regulation of canonical histone mRNAs: life without a poly(A) tail

The canonical histone proteins are encoded by replication-dependent genes and must rapidly reach high levels of expression during S phase. In metazoans the genes that encode these proteins produce mRNAs that, instead of being polyadenylated, contain a unique 3' end structure. By contrast, the synthesis of the variant, replication-independent histones, which are encoded by polyadenylated mRNAs, persists outside of S phase. Accurate positioning of both histone types in chromatin is essential for proper transcriptional regulation, the demarcation of heterochromatic boundaries and the epigenetic inheritance of gene expression patterns. Recent results suggest that the coordinated synthesis of replication-dependent and variant histone mRNAs is achieved by signals that affect formation of the 3' end of the replication-dependent histone mRNAs

Music Education as a Path to Positive Youth Development: An El Sistema-Inspired Program

The El Sistema music education philosophy links positive individual and social development through musical education. This study is a longitudinal examination of the impact of participation in an El Sistema-inspired program, the Miami Music Project, on positive youth development. We hypothesized that over the course of a school year, participation in ensemble-based after-school music programming would significantly enhance factors associated with positive youth development. Specifically, we evaluated social emotional constructs aligned with the Five Cs of Positive Youth Development: Competence, Confidence, Caring, Character, and Connection. Results revealed that participants showed significant increases across all five Cs over the course of the year. Additionally, findings showed that Miami Music Project students showed greater enhancements over time in Character, Competence and Caring when compared to a group of youth who did not participate in music education. This study presents empirical documentation of the numerous meaningful social and emotional enhancements that participation in an El Sistema-inspired program is engendering among youth. In this type of rigorous orchestral model of musical instruction, youth seem to acquire not only cognitive benefits but also a host of social and emotional enhancements, ostensibly from learning in an environment that requires disciplined social cohesion. These findings provide insight into the holistic approach foundational to the El Sistema philosophy and adds to our overall understanding of musical instruction in important ways