2,156 research outputs found
Birthweight and risk markers for type 2 diabetes and cardiovascular disease in childhood: the Child Heart and Health Study in England (CHASE).
AIMS/HYPOTHESIS: Lower birthweight (a marker of fetal undernutrition) is associated with higher risks of type 2 diabetes and cardiovascular disease (CVD) and could explain ethnic differences in these diseases. We examined associations between birthweight and risk markers for diabetes and CVD in UK-resident white European, South Asian and black African-Caribbean children.
METHODS: In a cross-sectional study of risk markers for diabetes and CVD in 9- to 10-year-old children of different ethnic origins, birthweight was obtained from health records and/or parental recall. Associations between birthweight and risk markers were estimated using multilevel linear regression to account for clustering in children from the same school.
RESULTS: Key data were available for 3,744 (66%) singleton study participants. In analyses adjusted for age, sex and ethnicity, birthweight was inversely associated with serum urate and positively associated with systolic BP. After additional height adjustment, lower birthweight (per 100 g) was associated with higher serum urate (0.52%; 95% CI 0.38, 0.66), fasting serum insulin (0.41%; 95% CI 0.08, 0.74), HbA1c (0.04%; 95% CI 0.00, 0.08), plasma glucose (0.06%; 95% CI 0.02, 0.10) and serum triacylglycerol (0.30%; 95% CI 0.09, 0.51) but not with BP or blood cholesterol. Birthweight was lower among children of South Asian (231 g lower; 95% CI 183, 280) and black African-Caribbean origin (81 g lower; 95% CI 30, 132). However, adjustment for birthweight had no effect on ethnic differences in risk markers.
CONCLUSIONS/INTERPRETATION: Birthweight was inversely associated with urate and with insulin and glycaemia after adjustment for current height. Lower birthweight does not appear to explain emerging ethnic difference in risk markers for diabetes
Hypermatrix factors for string and membrane junctions
The adjoint representations of the Lie algebras of the classical groups
SU(n), SO(n), and Sp(n) are, respectively, tensor, antisymmetric, and symmetric
products of two vector spaces, and hence are matrix representations. We
consider the analogous products of three vector spaces and study when they
appear as summands in Lie algebra decompositions. The Z3-grading of the
exceptional Lie algebras provide such summands and provides representations of
classical groups on hypermatrices. The main natural application is a formal
study of three-junctions of strings and membranes. Generalizations are also
considered.Comment: 25 pages, 4 figures, presentation improved, minor correction
The Gluon Propagator without lattice Gribov copies
We study the gluon propagator in quenched lattice QCD using the Laplacian
gauge which is free of lattice Gribov copies. We compare our results with those
obtained in the Landau gauge on the lattice, as well as with various
approximate solutions of the Dyson Schwinger equations. We find a finite value
for the renormalized zero-momentum propagator
(taking our renormalization point at 1.943 GeV), and a pole mass MeV.Comment: Discussion of the renormalized gluon propagator and of the Laplacian
gauge fixing procedure extended. Version to appear in Phys. Rev. D. 15 pages,
8 figure
Elevated expression of artemis in human fibroblast cells is associated with cellular radiosensitivity and increased apoptosis
Copyright @ 2012 Nature Publishing GroupThis article has been made available through the Brunel Open Access Publishing Fund.Background: The objective of this study was to determine the molecular mechanism(s) responsible for cellular radiosensitivity in two human fibroblast cell lines 84BR and 175BR derived from two cancer patients. Methods: Clonogenic assays were performed following exposure to increasing doses of gamma radiation to confirm radiosensitivity. γ-H2AX foci assays were used to determine the efficiency of DNA double strand break (DSB) repair in cells. Quantitative-PCR (Q-PCR) established the expression levels of key DNA DSB repair proteins. Imaging flow cytometry using Annexin V-FITC was used to compare artemis expression and apoptosis in cells. Results: Clonogenic cellular hypersensitivity in the 84BR and 175BR cell lines was associated with a defect in DNA DSB repair measured by the γ-H2AX foci assay. Q-PCR analysis and imaging flow cytometry revealed a two-fold overexpression of the artemis DNA repair gene which was associated with an increased level of apoptosis in the cells before and after radiation exposure. Over-expression of normal artemis protein in a normal immortalised fibroblast cell line NB1-Tert resulted in increased radiosensitivity and apoptosis. Conclusion: We conclude elevated expression of artemis is associated with higher levels of DNA DSB, radiosensitivity and elevated apoptosis in two radio-hypersensitive cell lines. These data reveal a potentially novel mechanism responsible for radiosensitivity and show that increased artemis expression in cells can result in either radiation resistance or enhanced sensitivity.This work was supported in part by The Vidal Sassoon Foundation USA. This article is made available through the Brunel Open Access Publishing Fund
Modelling the nucleon wave function from soft and hard processes
Current light-cone wave functions for the nucleon are unsatisfactory since
they are in conflict with the data of the nucleon's Dirac form factor at large
momentum transfer. Therefore, we attempt a determination of a new wave function
respecting theoretical ideas on its parameterization and satisfying the
following constraints: It should provide a soft Feynman contribution to the
proton's form factor in agreement with data; it should be consistent with
current parameterizations of the valence quark distribution functions and
lastly it should provide an acceptable value for the \jp \to N \bar N decay
width. The latter process is calculated within the modified perturbative
approach to hard exclusive reactions. A simultaneous fit to the three sets of
data leads to a wave function whose -dependent part, the distribution
amplitude, shows the same type of asymmetry as those distribution amplitudes
constrained by QCD sum rules. The asymmetry is however much more moderate as in
those amplitudes. Our distribution amplitude resembles the asymptotic one in
shape but the position of the maximum is somewhat shifted.Comment: 32 pages RevTex + PS-file with 5 figures in uu-encoded, compressed
fil
Infrared behavior of the gluon propagator in lattice Landau gauge: the three-dimensional case
We evaluate numerically the three-momentum-space gluon propagator in the
lattice Landau gauge, for three-dimensional pure-SU(2) lattice gauge theory
with periodic boundary conditions. Simulations are done for nine different
values of the coupling , from (strong coupling) to (in the scaling region), and for lattice sizes up to . In the
limit of large lattice volume we observe, in all cases, a gluon propagator
decreasing for momenta smaller than a constant value . From our data
we estimate MeV. The result of a gluon propagator
decreasing in the infrared limit has a straightforward interpretation as
resulting from the proximity of the so-called first Gribov horizon in the
infrared directions.Comment: 14 pages, BI-TP 99/03 preprint, correction in the Acknowledgments
section. To appear in Phys.Rev.
Slavnov-Taylor identities in Coulomb gauge Yang-Mills theory
The Slavnov-Taylor identities of Coulomb gauge Yang-Mills theory are derived
from the (standard, second order) functional formalism. It is shown how these
identities form closed sets from which one can in principle fully determine the
Green's functions involving the temporal component of the gauge field without
approximation, given appropriate input.Comment: 20 pages, no figure
Entrepreneurial sons, patriarchy and the Colonels' experiment in Thessaly, rural Greece
Existing studies within the field of institutional entrepreneurship explore how entrepreneurs influence change in economic institutions. This paper turns the attention of scholarly inquiry on the antecedents of deinstitutionalization and more specifically, the influence of entrepreneurship in shaping social institutions such as patriarchy. The paper draws from the findings of ethnographic work in two Greek lowland village communities during the military Dictatorship (1967–1974). Paradoxically this era associated with the spread of mechanization, cheap credit, revaluation of labour and clear means-ends relations, signalled entrepreneurial sons’ individuated dissent and activism who were now able to question the Patriarch’s authority, recognize opportunities and act as unintentional agents of deinstitutionalization. A ‘different’ model of institutional change is presented here, where politics intersects with entrepreneurs, in changing social institutions. This model discusses the external drivers of institutional atrophy and how handling dissensus (and its varieties over historical time) is instrumental in enabling institutional entrepreneurship
The ACS Virgo Cluster Survey. XII. The Luminosity Function of Globular Clusters in Early Type Galaxies
We analyze the luminosity function of the globular clusters (GCs) belonging
to the early-type galaxies observed in the ACS Virgo Cluster Survey. We have
obtained estimates for a Gaussian representation of the GC luminosity function
(GCLF) for 89 galaxies. We have also fit the GCLFs with an "evolved Schechter
function", which is meant to reflect the preferential depletion of low-mass
GCs, primarily by evaporation due to two-body relaxation, from an initial
Schechter mass function similar to that of young massive clusters. We find a
significant trend of the GCLF dispersion with galaxy luminosity, in the sense
that smaller galaxies have narrower GCLFs. We show that this narrowing of the
GCLF in a Gaussian description is driven by a steepening of the GC mass
function above the turnover mass, as one moves to smaller host galaxies. We
argue that this behavior at the high-mass end of the GC mass function is most
likely a consequence of systematic variations of the initial cluster mass
function. The GCLF turnover mass M_TO is roughly constant, at ~ 2.2 x 10^5
M_sun in bright galaxies, but it decreases slightly in dwarfs with M_B >~ -18.
We show that part of the variation could arise from the shorter dynamical
friction timescales in smaller galaxies. We probe the variation of the GCLF to
projected galactocentric radii of 20-35 kpc in the Virgo giants M49 and M87,
finding that M_TO is essentially constant over these spatial scales. Our fits
of evolved Schechter functions imply average dynamical mass losses (Delta) over
a Hubble time that fall in the range 2 x 10^5 <~ (Delta/M_sun) < 10^6 per GC.
We agree with previous suggestions that if the full GCLF is to be understood in
more detail GCLF models will have to include self-consistent treatments of
dynamical evolution inside time-dependent galaxy potentials. (Abridged)Comment: 46 pages, 20 figures, 6 tables. Accepted for publication in ApJS.
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