Illicit substance use among university students from seven European countries: A comparison of personal and perceived peer use and attitudes towards illicit substance use

Objective: To compare European students' personal use and approval of illicit substance use with their perceptions of peer behaviours and attitudes, and investigate whether perceptions of peer norms are associated with personal use of illicit substances and attitudes. Method: This study used baseline data fromthe Social Norms Intervention for the prevention of Polydrug usE (SNIPE) project involving 4482 students from seven European countries in 2012. Students completed an online surveywhich included questions on personal and perceived peer illicit substance use and personal and perceived peer attitude towards illicit substances. Results: 8.3% of students reported having used illicit substances at least once in their life. 49.7% of students perceived that the majority of their peers have used illicit substances more frequently than themselves. The perception was significantly associated with higher odds for personal illicit substance use (OR: 1.97, 95% CI: 1.53–2.54). The perception that the majority of peers approve illicit substance use was significantly associated with higher odds for personal approval of illicit substance use (OR: 3.47, 95% CI: 2.73–4.41). Conclusion: Students commonly perceived that their peers used illicit subtances more often than themselves. We found an association between the perceived peer norms/attitudes and reported individual behaviour/ attitudes

The interfascicular matrix enables fascicle sliding and recovery in tendon, and behaves more elastically in energy storing tendons

While the predominant function of all tendons is to transfer force from muscle to bone and position the limbs, some tendons additionally function as energy stores, reducing the cost of locomotion. Energy storing tendons experience extremely high strains and need to be able to recoil efficiently for maximum energy storage and return. In the equine forelimb, the energy storing superficial digital flexor tendon (SDFT) has much higher failure strains than the positional common digital extensor tendon (CDET). However, we have previously shown that this is not due to differences in the properties of the SDFT and CDET fascicles (the largest tendon subunits). Instead, there is a greater capacity for interfascicular sliding in the SDFT which facilitates the greater extensions in this particular tendon (Thorpe et al., 2012). In the current study, we exposed fascicles and interfascicular matrix (IFM) from the SDFT and CDET to cyclic loading followed by a test to failure. The results show that IFM mechanical behaviour is not a result of irreversible deformation, but the IFM is able to withstand cyclic loading, and is more elastic in the SDFT than in the CDET. We also assessed the effect of ageing on IFM properties, demonstrating that the IFM is less able to resist repetitive loading as it ages, becoming stiffer with increasing age in the SDFT. These results provide further indications that the IFM is important for efficient function in energy storing tendons, and age-related alterations to the IFM may compromise function and predispose older tendons to injury

Self-energy and Self-force in the Space-time of a Thick Cosmic String

We calculate the self-energy and self-force for an electrically charged particle at rest in the background of Gott-Hiscock cosmic string space-time. We found the general expression for the self-energy which is expressed in terms of the $S$ matrix of the scattering problem. The self-energy continuously falls down outward from the string's center with maximum at the origin of the string. The self-force is repulsive for an arbitrary position of the particle. It tends to zero in the string's center and also far from the string and it has a maximum value at the string's surface. The plots of the numerical calculations of the self-energy and self-force are shown.Comment: 15 pages, 4 Postscript figures, ReVTe

The Value of Information for Populations in Varying Environments

The notion of information pervades informal descriptions of biological systems, but formal treatments face the problem of defining a quantitative measure of information rooted in a concept of fitness, which is itself an elusive notion. Here, we present a model of population dynamics where this problem is amenable to a mathematical analysis. In the limit where any information about future environmental variations is common to the members of the population, our model is equivalent to known models of financial investment. In this case, the population can be interpreted as a portfolio of financial assets and previous analyses have shown that a key quantity of Shannon's communication theory, the mutual information, sets a fundamental limit on the value of information. We show that this bound can be violated when accounting for features that are irrelevant in finance but inherent to biological systems, such as the stochasticity present at the individual level. This leads us to generalize the measures of uncertainty and information usually encountered in information theory

Magnetic Moments of JP=3/2+J^P=3/2^+ Heavy Baryons Using Effective Mass and Screened Charge Scheme

Magnetic moments of heavy charmed baryons with $J^P=3/2^+$ are predicted employing the concept of effective quark mass and screened charge of quark. We also extend our scheme to predict the $3/2^+ --> 1/2^+$ transition magnetic moments. A comparison of our results with the predictions obtained in recent models is presented.Comment: 19 pages, Accepted for publication in EPJ-

Genetic and clinical analyses of psychosis spectrum symptoms in a large multiethnic youth cohort reveal significant link with ADHD

Psychotic symptoms are not only an important feature of severe neuropsychiatric disorders, but are also common in the general population, especially in youth. The genetic etiology of psychosis symptoms in youth remains poorly understood. To characterize genetic risk for psychosis spectrum symptoms (PS), we leverage a community-based multiethnic sample of children and adolescents aged 8–22 years, the Philadelphia Neurodevelopmental Cohort (n = 7225, 20% PS). Using an elastic net regression model, we aim to classify PS status using polygenic scores (PGS) based on a range of heritable psychiatric and brain-related traits in a multi-PGS model. We also perform univariate PGS associations and evaluate age-specific effects. The multi-PGS analyses do not improve prediction of PS status over univariate models, but reveal that the attention deficit hyperactivity disorder (ADHD) PGS is robustly and uniquely associated with PS (OR 1.12 (1.05, 1.18) P = 0.0003). This association is driven by subjects of European ancestry (OR = 1.23 (1.14, 1.34), P = 4.15 × 10−7) but is not observed in African American subjects (P = 0.65). We find a significant interaction of ADHD PGS with age (P = 0.01), with a stronger association in younger children. The association is independent of phenotypic overlap between ADHD and PS, not indirectly driven by substance use or childhood trauma, and appears to be specific to PS rather than reflecting general psychopathology in youth. In an independent sample, we replicate an increased ADHD PGS in 328 youth at clinical high risk for psychosis, compared to 216 unaffected controls (OR 1.06, CI(1.01, 1.11), P = 0.02). Our findings suggest that PS in youth may reflect a different genetic etiology than psychotic symptoms in adulthood, one more akin to ADHD, and shed light on how genetic risk can be investigated across early disease trajectories

Gender norms and social norms: differences, similarities and why they matter in prevention science.

Two streams of theory and practice on gender equity have begun to elide. The first is work conducted to change social norms, particularly using theory that emerged from studies in social psychology. The second is work done on gender norms, emerging historically from feminist scholars working to counter gender inequality. As these two streams of work intersect, conceptual clarity is needed to understand differences and similarities between these two traditions. Increased clarity will improve efforts to address harmful norms and practices. In this article, we review similarities and differences between social and gender norms, reviewing the history of the concepts and identifying key tension points of contrast. We identified six areas of comparison that might be helpful for practitioners working for the promotion of global health as they make sense of social and gender norms. We then offer a definition of gender norms for practitioners and researchers working at the intersection between these two theories. Our definition draws from the two different streams of thought of how norms influence people's actions, acknowledging the double nature of gender norms: beliefs nested in people's minds and embedded in institutions that profoundly affect health-related behaviours and shape differential access to health services

Genetic and clinical analyses of psychosis spectrum symptoms in a large multiethnic youth cohort reveal significant link with ADHD

Psychotic symptoms are not only an important feature of severe neuropsychiatric disorders, but are also common in the general population, especially in youth. The genetic etiology of psychosis symptoms in youth remains poorly understood. To characterize genetic risk for psychosis spectrum symptoms (PS), we leverage a community-based multiethnic sample of children and adolescents aged 8–22 years, the Philadelphia Ne