Rapidly rotating second-generation progenitors for the blue hook stars of {\omega} Cen

Horizontal Branch stars belong to an advanced stage in the evolution of the oldest stellar galactic population, occurring either as field halo stars or grouped in globular clusters. The discovery of multiple populations in these clusters, that were previously believed to have single populations gave rise to the currently accepted theory that the hottest horizontal branch members (the blue hook stars, which had late helium-core flash ignition, followed by deep mixing) are the progeny of a helium-rich "second generation" of stars. It is not known why such a supposedly rare event (a late flash followed by mixing) is so common that the blue hook of {\omega} Cen contains \sim 30% of horizontal branch stars 10 , or why the blue hook luminosity range in this massive cluster cannot be reproduced by models. Here we report that the presence of helium core masses up to \sim 0.04 solar masses larger than the core mass resulting from evolution is required to solve the luminosity range problem. We model this by taking into account the dispersion in rotation rates achieved by the progenitors, whose premain sequence accretion disc suffered an early disruption in the dense environment of the cluster's central regions where second-generation stars form. Rotation may also account for frequent late-flash-mixing events in massive globular clusters.Comment: 44 pages, 8 figures, 2 tables in Nature, online june 22, 201

Relevant prior knowledge moderates the effect of elaboration during small group discussion on academic achievement

This study set out to test whether relevant prior knowledge would moderate a positive effect on academic achievement of elaboration during small-group discussion. In a 2 × 2 experimental design, 66 undergraduate students observed a video showing a small-group problem-based discussion about thunder and lightning. In the video, a teacher asked questions to the observing participants. Participants either elaborated by responding to these questions, or did not elaborate, but completed a

Psychological morbidity and health related quality of life after injury: multicentre cohort study

Purpose: To demonstrate the impact of psychological morbidity 1 month post-injury on subsequent post-injury quality of life (HRQoL) in a general injury population in the UK to inform development of trauma care and rehabilitation services. Methods: Multicentre cohort study of 16–70-year-olds admitted to 4 UK hospitals following injury. Psychological morbidity and HRQoL (EQ-5D-3L) were measured at recruitment and 1, 2, 4 and 12 months post-injury. A reduction in EQ-5D compared to retrospectively assessed pre-injury levels of at least 0.074 was taken as the minimal important difference (MID). Multilevel logistic regression explored relationships between psychological morbidity 1 month post-injury and MID in HRQoL over the 12 months after injury. Results: A total of 668 adults participated. Follow-up rates were 77% (1 month) and 63% (12 months). Substantial reductions in HRQoL were seen; 93% eported a MID at 1 month and 58% at 12 months. Problems with pain, mobility and usual activities were commonly reported at each time point. Depression and anxiety scores month post-injury were independently associated with subsequent MID in HRQoL. The relationship between depression and HRQoL was partly explained by anxiety and to a lesser extent by pain and social functioning. The relationship between anxiety and HRQoL was not explained by factors measured in our study. Conclusions: Hospitalised injuries result in substantial reductions in HRQoL up to 12 months later. Depression and anxiety early in the recovery period are independently associated with lower HRQoL. Identifying and managing these problems, ensuring adequate pain control and facilitating social functioning are key elements in improving HRQoL post-injury

Parental Monitoring During Early Adolescence Deters Adolescent Sexual Initiation: Discrete-Time Survival Mixture Analysis

We used discrete-time survival mixture modeling to examine 5,305 adolescents from the 1997 National Longitudinal Survey of Youth regarding the impact of parental monitoring during early adolescence (ages 14–16) on initiation of sexual intercourse and problem behavior engagement (ages 14–23). Four distinctive parental-monitoring groups were identified and labeled as “High,” “Increasing,” “Decreasing,” and “Low”. About 68% of adolescents received a high level of parental monitoring from ages 14 to 16 (High), 6 and 9% respectively exhibited an accelerated (Increasing) and a decelerated trajectory (Decreasing), and 17% had consistently low parental monitoring (Low). Relative to participants in the Low group, adolescents in the High group delayed sexual initiation by 1.5 years. Males, relative to females, were more likely to have had a low trajectory of parental monitoring, and were more likely to initiate sexual intercourse before age 14. In contrast to White Adolescents, Hispanics and Blacks were less likely to receive High parental monitoring, and had a higher rate of early sexual initiation before age 14. The study demonstrates the temporal relationship of parental monitoring with adolescent sexual initiation from a longitudinal perspective. An increase of parental monitoring across ages is accompanied with a decrease of sexual risk. The continual high level of parental monitoring from ages 14 to 16 also mitigated the risk of engagement in substance use and delinquent behaviors from ages 14 to 23

Tephrochronology

Tephrochronology is the use of primary, characterized tephras or cryptotephras as chronostratigraphic marker beds to connect and synchronize geological, paleoenvironmental, or archaeological sequences or events, or soils/paleosols, and, uniquely, to transfer relative or numerical ages or dates to them using stratigraphic and age information together with mineralogical and geochemical compositional data, especially from individual glass-shard analyses, obtained for the tephra/cryptotephra deposits. To function as an age-equivalent correlation and chronostratigraphic dating tool, tephrochronology may be undertaken in three steps: (i) mapping and describing tephras and determining their stratigraphic relationships, (ii) characterizing tephras or cryptotephras in the laboratory, and (iii) dating them using a wide range of geochronological methods. Tephrochronology is also an important tool in volcanology, informing studies on volcanic petrology, volcano eruption histories and hazards, and volcano-climate forcing. Although limitations and challenges remain, multidisciplinary applications of tephrochronology continue to grow markedly

Ventral and dorsal striatal dopamine efflux and behavior in rats with simple vs. co-morbid histories of cocaine sensitization and neonatal ventral hippocampal lesions

xposing animal models of mental illness to addictive drugs provides an approach to understanding the neural etiology of dual diagnosis disorders. Previous studies have shown that neonatal ventral hippocampal lesions (NVHL) in rats produce features of both schizophrenia and addiction vulnerability. Objective This study investigated ventral and dorsal striatal dopamine (DA) efflux in NVHL rats combined with behavioral sensitization to cocaine. Methods Adult NVHL vs. SHAM-operated rats underwent a 5-day injection series of cocaine (15 mg/kg/day) vs. saline. One week later, rats were cannulated in nucleus accumbens SHELL, CORE, or caudate–putamen. Another week later, in vivo microdialysis sampled DA during locomotor testing in which a single cocaine injection (15 mg/kg) was delivered. Results NVHLs and cocaine history significantly increased behavioral activation approximately 2-fold over SHAM-saline history rats. DA efflux curves corresponded time dependently with the cocaine injection and locomotor curves and varied significantly by striatal region: Baseline DA levels increased 5-fold while cocaine-stimulated DA efflux decreased by half across a ventral to dorsal striatal gradient. However, NVHLs, prior cocaine history, and individual differences in behavior were not underpinned by differential DA efflux overall or within any striatal region.Conclusion Differences in ventral/dorsal striatal DA efflux are not present in and are not required for producing differential levels of acute cocaine-induced behavioral activation in NVHLs with and without a behaviorally sensitizing cocaine history. These findings suggest other neurotransmitter systems, and alterations in striatal network function post-synaptic to DA transmission are more important to understanding the interactive effects of addictive drugs and mental illness

Stroke secondary prevention, a non-surgical and non-pharmacological consensus definition : results of a Delphi study

OBJECTIVE: Evidence supporting lifestyle modification in vascular risk reduction is limited, drawn largely from primary prevention studies. To advance the evidence base for non-pharmacological and non-surgical stroke secondary prevention (SSP), empirical research is needed, informed by a consensus-derived definition of SSP. To date, no such definition has been published. We used Delphi methods to generate an evidence-based definition of non-pharmacological and non-surgical SSP. RESULTS: The 16 participants were members of INSsPiRE (International Network of Stroke Secondary Prevention Researchers), a multidisciplinary group of trialists, academics and clinicians. The Elicitation stage identified 49 key elements, grouped into 3 overarching domains: Risk factors, Education, and Theory before being subjected to iterative stages of elicitation, ranking, discussion, and anonymous voting. In the Action stage, following an experience-based engagement with key stakeholders, a consensus-derived definition, complementing current pharmacological and surgical SSP pathways, was finalised: Non-pharmacological and non-surgical stroke secondary prevention supports and improves long-term health and well-being in everyday life and reduces the risk of another stroke, by drawing from a spectrum of theoretically informed interventions and educational strategies. Interventions to self-manage modifiable lifestyle risk factors are contextualized and individualized to the capacities, needs, and personally meaningful priorities of individuals with stroke and their families