Cohort profile: the DASH (determinants of adolescent social well-being and health) study, an ethnically diverse cohort

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The Effect of Different Magnetospheric Structures on Predictions of Gamma-ray Pulsar Light Curves

The second pulsar catalogue of the Fermi Large Area Telescope (LAT) will contain in excess of 100 gamma-ray pulsars. The light curves (LCs) of these pulsars exhibit a variety of shapes, and also different relative phase lags with respect to their radio pulses, hinting at distinct underlying emission properties (e.g., inclination and observer angles) for the individual pulsars. Detailed geometric modelling of the radio and gamma-ray LCs may provide constraints on the B-field structure and emission geometry. We used different B-field solutions, including the static vacuum dipole and the retarded vacuum dipole, in conjunction with an existing geometric modelling code, and constructed radiation sky maps and LCs for several different pulsar parameters. Standard emission geometries were assumed, namely the two-pole caustic (TPC) and outer gap (OG) models. The sky maps and LCs of the various B-field and radiation model combinations were compared to study their effect on the resulting LCs. As an application, we compared our model LCs with Fermi LAT data for the Vela pulsar, and inferred the most probable configuration in this case, thereby constraining Vela's high-altitude magnetic structure and system geometry.Comment: 6 pages, 4 figures, conference article, appears in Proceedings of SAIP2012, the 57th Annual Conference of the South African Institute of Physics, edited by Johan Janse van Rensburg, ISBN: 978-1-77592-070-

High Energy Neutrinos and Photons from Curvature Pions in Magnetars

We discuss the relevance of the curvature radiation of pions in strongly magnetized pulsars or magnetars, and their implications for the production of TeV energy neutrinos detectable by cubic kilometer scale detectors, as well as high energy photons.Comment: 19 pages, 4 figures, to appear in JCA

Nonlinear wave interaction and spin models in the MHD regime

Here we consider the influence on the electron spin in the MHD regime. Recently developed models which include spin-velocity correlations are taken as a starting point. A theoretical argument is presented, suggesting that in the MHD regime a single fluid electron model with spin correlations is equivalent to a model with spin-up and spin-down electrons constituting different fluids, but where the spin-velocity correlations are omitted. Three wave interaction of 2 shear Alfven waves and a compressional Alfven wave is then taken as a model problem to evaluate the asserted equivalence. The theoretical argument turns out to be supported, as the predictions of the two models agree completely. Furthermore, the three wave coupling coefficients obey the Manley-Rowe relations, which give further support to the soundness of the models and the validity of the assumptions made in the derivation. Finally we point out that the proposed two-fluid model can be incorporated in standard Particle-In-Cell schemes with only minor modifications.Comment: 8 page

Perceived parenting and psychological well-being in UK ethnic minority adolescents

Background: Warm, caring parenting with appropriate supervision and control is considered to contribute to the best mental health outcomes for young people. The extent to which this view on ‘optimal’ parenting and health applies across ethnicities, warrants further attention. We examined associations between perceived parental care and parental control and psychological well-being among ethnically diverse UK adolescents.<p></p> Methods: In 2003 a sample of 4349 pupils aged 11–13 years completed eight self-reported parenting items. These items were used to derive the parental care and control scores. Higher score represents greater care and control, respectively. Psychological well-being was based on total psychological difficulties score from Goodman's Strengths and Difficulties Questionnaire, increasing score corresponding to increasing difficulties.<p></p> Results: All minority pupils had lower mean care and higher mean control scores compared with Whites. In models stratified by ethnicity, increasing parental care was associated with lower psychological difficulties score (better mental health) and increasing parental control with higher psychological difficulties score within each ethnic group, compared with reference categories. The difference in psychological difficulties between the highest and lowest tertiles of parental care, adjusted for age, sex, family type and socio-economic circumstances, was: White UK =−2.92 (95% confidence interval −3.72, −2.12); Black Caribbean =−2.08 (−2.94, −1.22); Nigerian/Ghanaian =−2.60 (−3.58, −1.62); Other African =−3.12 (−4.24, −2.01); Indian =−2.77 (−4.09, −1.45); Pakistani/ Bangladeshi =−3.15 (−4.27, −2.03). Between ethnic groups (i.e. in models including ethnicity), relatively better mental health of minority groups compared with Whites was apparent even in categories of low care and low autonomy. Adjusting for parenting scores, however, did not fully account for the protective effect of minority ethnicity.<p></p> Conclusions: Perceived quality of parenting is a correlate of psychological difficulties score for all ethnic groups despite differences in reporting. It is therefore likely that programmes supporting parenting will be effective regardless of ethnicity.<p></p&gt