Simulations and cosmological inference: A statistical model for power spectra means and covariances

We describe an approximate statistical model for the sample variance distribution of the non-linear matter power spectrum that can be calibrated from limited numbers of simulations. Our model retains the common assumption of a multivariate Normal distribution for the power spectrum band powers, but takes full account of the (parameter dependent) power spectrum covariance. The model is calibrated using an extension of the framework in Habib et al. (2007) to train Gaussian processes for the power spectrum mean and covariance given a set of simulation runs over a hypercube in parameter space. We demonstrate the performance of this machinery by estimating the parameters of a power-law model for the power spectrum. Within this framework, our calibrated sample variance distribution is robust to errors in the estimated covariance and shows rapid convergence of the posterior parameter constraints with the number of training simulations.Comment: 14 pages, 3 figures, matches final version published in PR

Behavioural early-life exposures and body composition at age 15 years

BACKGROUND/OBJECTIVES: Previous studies have demonstrated associations between some early-life exposures and later obesity, but most have used body mass index in childhood or adulthood as the outcome. The objective of this study was to investigate whether early-life exposures were associated with directly measured fat and lean mass in adolescence. SUBJECTS/METHODS: This study used data on 4750 mother–offspring pairs, collected as a part of the Avon Longitudinal Study of Parents and Children, Bristol, UK between 1991 and 1992; associations between behavioural exposures occurring from conception up to 5 years of age (maternal and paternal smoking during pregnancy, breastfeeding, age at introduction to solids, dietary patterns and physical inactivity during early childhood) and offspring body composition measured by dual-energy X-ray absorptiometry at ~ 15 years were assessed. RESULTS: After full adjustment for potential confounders, maternal smoking during pregnancy, having a junk food diet and spending more time watching television in early childhood were all associated with higher fat mass at age 15, whereas maternal smoking, having a healthy diet and playing computer games more frequently in early childhood were all associated with a higher lean mass at age 15. Associations with paternal smoking were generally weaker for both fat and lean mass, but as there was no strong statistical evidence for maternal vs paternal differences, confounding by social factors rather than a direct effect of maternal smoking cannot be ruled out. Early feeding was not associated with fat or lean mass at age 15. CONCLUSIONS: This study does not provide compelling evidence for associations between most early-life factors and body composition in adolescence. However, possible associations with dietary patterns and physical inactivity in early childhood require further investigation in other cohorts that have direct measurements of adolescent body composition.SD Leary, DA Lawlor, G Davey Smith, MJ Brion and AR Nes

The tracking of active travel and its relationship with body composition in UK adolescents

AbstractBackgroundTo examine the tracking of active travel through adolescence, and its association with body mass index (BMI) and fat mass at age 17 in a UK cohort.MethodsWe analysed data collected from the Avon Longitudinal Study of Parents and Children (ALSPAC). The analyses include all participants with self-reported travel mode to school at ages 12, 14 and 16 years, and measured height, weight and body composition at age 17 (n=2,026). Tracking coefficients were calculated for individual travel behaviours (including walking and cycling) through adolescence using Generalised Estimating Equations. Linear regression analyses examined associations between travel pattern (consistently passive, consistently active, active at two time points or active at one time point), BMI, and DXA-measured fat mass (expressed as internally derived standard deviation scores) at 17 years. Analyses were adjusted for height (where appropriate), sex, age, parental social class, and maternal education with interaction terms to assess sex differences.ResultsThere was substantial tracking in active travel through adolescence, with 38.5% of males and 32.3% of females consistently walking or cycling to school. In males, a consistently or predominantly active travel pattern was associated with a lower BMI SD score at age 17 (consistently active: adjusted β=−0.23; 95% CI −0.40, −0.06; active at two time points: adjusted β−0.30; 95% CI −0.50, −0.10) compared to those with a consistently passive pattern. No associations were seen in females.ConclusionsMaintenance of active travel behaviours throughout adolescence may help to protect against the development of excess BMI in males. In addition to encouraging the adoption of active travel to school, public health messages should aim to prevent drop out from active travel to promote good health in youth

Epidemiology of Lead Poisoning in Cattle

The case histories of lead poisoning diagnosed in 63 herds of cattle over the past five years were studied. The toxicosis was found to be most prominent during the spring months and resulted in a 61 percent fatality rate. The clinical signs observed involved mainly the central nervous and gastrointestinal systems, as did the post mortem findings. The mean tissue lead levels were determined and correlated with the source of the toxicant

Unbiased Global Optimization of Lennard-Jones Clusters for N <= 201 by Conformational Space Annealing Method

We apply the conformational space annealing (CSA) method to the Lennard-Jones clusters and find all known lowest energy configurations up to 201 atoms, without using extra information of the problem such as the structures of the known global energy minima. In addition, the robustness of the algorithm with respect to the randomness of initial conditions of the problem is demonstrated by ten successful independent runs up to 183 atoms. Our results indicate that the CSA method is a general and yet efficient global optimization algorithm applicable to many systems.Comment: revtex, 4 pages, 2 figures. Physical Review Letters, in pres

The characteristics of sexual abuse in sport: A multidimensional scaling analysis of events described in media reports

Most research on sexual abuse has been conducted within family settings (Fergusson & Mullen, 1999). In recent years, following several high profile convictions and scandals, research into sexual abuse has also encompassed institutional and community settings such as sport and the church (Gallagher, 2000; Wolfe et al., 2003). Research into sexual abuse in sport, for example, began with both prevalence studies (Kirby & Greaves, 1996; Leahy, Pretty & Tenenbaum, 2002) and qualitative analyses of the processes and experiences of athlete sexual abuse (Brackenridge, 1997; Cense & Brackenridge, 2001, Toftegaard Nielsen, 2001). From such work, descriptions of the modus operandi of abusers in sport, and the experiences and consequences for athlete victims, have been provided, informing both abuse prevention work and coach education. To date, however, no study has provided empirical support for multiple associations or identified patterns of sex offending in sport in ways that might allow comparisons with research-generated models of offending outside sport. This paper reports on an analysis of 159 cases of criminally defined sexual abuse, reported in the print media over a period of 15 years. The main aim of the study was to identify the nature of sex offending in sport focusing on the methods and locations of offences. The data were analysed using multidimensional scaling (MDS), as a data reduction method, in order to identify the underlying themes within the abuse and explore the inter-relationships of behaviour, victim and context variables. The findings indicate that there are specific themes that can be identified within the perpetrator strategies that include ‘intimate’, ‘aggressive’, and ‘’dominant’ modes of interaction. The same patterns that are described here within the specific context of sport are consistent with themes that emerge from similar behavioural analyses of rapists (Canter & Heritage, 1990; Bishopp, 2003) and child molester groups (Canter, Hughes & Kirby, 1998). These patterns show a correspondence to a broader behavioural model – the interpersonal circumplex (e.g., Leary 1957). Implications for accreditation and continuing professional education of sport psychologists are noted

Superconducting Rebalance Accelerometer

A multi-axis accelerometer which utilizes a magnetically-suspended, high-TC proof mass is under development. The design and performance of a single axis device which is stabilized actively in the axial direction but which utilizes ring magnets for passive radial stabilization is discussed. The design of a full six degree-of-freedom device version is also described

Multiple Sclerosis Patient Sequence Variation In Epstein-Barr Virus Nuclear Antigen 1

No abstract availabl