Complexification of Gauge Theories

For the case of a first-class constrained system with an equivariant momentum map, we study the conditions under which the double process of reducing to the constraint surface and dividing out by the group of gauge transformations $G$ is equivalent to the single process of dividing out the initial phase space by the complexification $G_C$ of $G$. For the particular case of a phase space action that is the lift of a configuration space action, conditions are found under which, in finite dimensions, the physical phase space of a gauge system with first-class constraints is diffeomorphic to a manifold imbedded in the physical configuration space of the complexified gauge system. Similar conditions are shown to hold in the infinite-dimensional example of Yang-Mills theories. As a physical application we discuss the adequateness of using holomorphic Wilson loop variables as (generalized) global coordinates on the physical phase space of Yang-Mills theory.Comment: 25pp., LaTeX, Syracuse SU-GP-93/6-2, Lisbon DF/IST 6.9

Common variants near MC4R are associated with fat mass, weight and risk of obesity.

To identify common variants influencing body mass index (BMI), we analyzed genome-wide association data from 16,876 individuals of European descent. After previously reported variants in FTO, the strongest association signal (rs17782313, P = 2.9 x 10(-6)) mapped 188 kb downstream of MC4R (melanocortin-4 receptor), mutations of which are the leading cause of monogenic severe childhood-onset obesity. We confirmed the BMI association in 60,352 adults (per-allele effect = 0.05 Z-score units; P = 2.8 x 10(-15)) and 5,988 children aged 7-11 (0.13 Z-score units; P = 1.5 x 10(-8)). In case-control analyses (n = 10,583), the odds for severe childhood obesity reached 1.30 (P = 8.0 x 10(-11)). Furthermore, we observed overtransmission of the risk allele to obese offspring in 660 families (P (pedigree disequilibrium test average; PDT-avg) = 2.4 x 10(-4)). The SNP location and patterns of phenotypic associations are consistent with effects mediated through altered MC4R function. Our findings establish that common variants near MC4R influence fat mass, weight and obesity risk at the population level and reinforce the need for large-scale data integration to identify variants influencing continuous biomedical traits

Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk

The microstructure of reaction-bonded silicon carbide

SIGLEAvailable from British Library Document Supply Centre- DSC:D58941/87 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Associations between executive attention and objectively measured physical activity in adolescence : findings from ALSPAC, a UK cohort

Studies of relationships between physical activity and children's attention skills are often constrained by small samples, lack of objective measurements and lack of control for confounders. The present study explores the relationship using objective measures of physical activity from a large birth cohort which permits both longitudinal and cross-sectional analyses. Data from 4755 participants (45% male) with valid measurement of physical activity (total volume and intensity) by accelerometry at age 11 from the Avon Longitudinal Study of Parents and Children (UK) were analysed. Attention was evaluated by the Test of Everyday Attention for Children (TEA-Ch) at 11 years and by the Cognitive Drug Research (CDR) computerised cognitive assessment system at 13 years. Males engaged in an average of 29 min (SD 17) of daily moderate-to-vigorous physical activity (MVPA) at age 11 years compared with 18 min (SD 12) among females. In unadjusted models, higher total volume of physical activity was associated with lower performance across attention tasks. When total volume of physical activity and potential confounding variables were controlled for, higher MVPA was associated with better performance at both 11 and 13 years. Correction for regression dilution approximately doubled the standardised β coefficients. We observed complex associations but results suggest that MVPA may be beneficial for attention processes in adolescence, especially in males. This has implications for interventions aimed at improving executive attention but may also be supportive of the benefits of physical activity for educational and mental health outcomes