557 research outputs found
Regional differences in overweight: an effect of people or place?
Objective: To examine UK country and English regional differences in childhood overweight (including obesity) at 3 years and determine whether any differences persist after adjustment for individual risk factors. Design: Nationally representative prospective study. Setting: England, Wales, Scotland and Northern Ireland. Participants: 13 194 singleton children from the UK Millennium Cohort Study with height and weight data at age 3 years. Main outcome measure: Overweight (including obesity) was defined according to the International Obesity TaskForce cut-offs for body mass index, which are age and sex specific. Results: At 3 years of age, 23% (3102) of children were overweight or obese. In univariable analyses, children from Northern Ireland (odds ratio 1.30, 95% confidence interval 1.14 to 1.48) and Wales (1.26, 1.11 to 1.44) were more likely to be overweight than children from England. There were no differences in overweight between children from Scotland and England. Within England, children from the East (0.71, 0.57 to 0.88) and South East regions (0.82, 0.68 to 0.99) were less likely to be overweight than children from London. There were no differences in overweight between children from other English regions and children from London. These differences were maintained after adjustment for individual socio-demographic characteristics and other risk factors for overweight. Conclusions: UK country and English regional differences in early childhood overweight are independent of individual risk factors. This suggests a role for policies to support environmental changes that remove barriers to physical activity or healthy eating in young children
Large extra dimensions, the galaxy power spectrum and the end of inflation
We consider the production of gravitational KK modes via cosmological
photon-photon and electron-positron annihilation in models with large
factorisable extra dimensions. We place constraints on this production using
recent results from a joint analysis of the power spectra of the 2dF Galaxy
Redshift Survey (2dFGS) and the cosmic microwave background (CMB) anisotropies.
We obtain a more accurate upper limit for the temperature corresponding to
matter-radiation equality and show that, even for the case of 6 extra
dimensions and a fundamental scale of 1 TeV, a period of inflation is required
that ends at a temperature much lower than that of the QCD phase transition.Comment: 12 pages, 2 figures, hadronic branching+typos corrected,accepted in
JHE
An ecological role for assortative mating under infection?
Wildlife diseases are emerging at a higher rate than ever before meaning that understanding their potential impacts is essential, especially for those species and populations that may already be of conservation concern. The link between population genetic structure and the resistance of populations to disease is well understood: high genetic diversity allows populations to better cope with environmental changes, including the outbreak of novel diseases. Perhaps following this common wisdom, numerous empirical and theoretical studies have investigated the link between disease and disassortative mating patterns, which can increase genetic diversity. Few however have looked at the possible link between disease and the establishment of assortative mating patterns. Given that assortative mating can reduce genetic variation within a population thus reducing the adaptive potential and long-term viability of populations, we suggest that this link deserves greater attention, particularly in those species already threatened by a lack of genetic diversity. Here, we summarise the potential broad scale genetic implications of assortative mating patterns and outline how infection by pathogens or parasites might bring them about. We include a review of the empirical literature pertaining to disease-induced assortative mating. We also suggest future directions and methodological improvements that could advance our understanding of how the link between disease and mating patterns influences genetic variation and long-term population viability.Funding was provided by Marie Curie Fellowship and
NERC PhD Studentship
Maternal health, pregnancy and birth outcomes for women involved in care proceedings in Wales: a linked data study
Background: Under the Children Act 1989, local authorities in Wales, UK, can issue care proceedings if they are concerned about the welfare of a child, which can lead to removal of a child from parents. For mothers at risk of child removal, timely intervention during pregnancy may avert the need for this and improve maternal/fetal health; however, little is known about this specific population during the antenatal period. The study examined maternity characteristics of mothers whose infants were subject to care proceedings, with the aim of informing preventative interventions targeted at high risk mothers. Methods: Anonymised administrative data from Cafcass Cymru, who provide child-focused advice and support for family court proceedings in Wales, were linked to population-based maternity and health records held within the Secure Anonymised Information Linkage Databank. Linked data were available for 1111 birth mothers of infants involved in care proceedings between 2015 and 2018. Findings were benchmarked with reference to an age-deprivation-matched comparison group (n = 23,414), not subject to care proceedings but accessing maternity services during this period. Demographic characteristics, maternal health, reproductive history, interaction with midwifery services, and pregnancy and birth outcomes were examined. Descriptive and statistical tests of independence were used. Results: Half of the women in the cohort (49.4%) resided in the most deprived areas. They were more likely to be younger at entry to motherhood (63.5% <21 years-of-age compared to 42.7% in the comparison group), to have mental health (28.6% compared to 8.2%) and substance use issues (10.4% compared to 0.6%) and to smoke (62.7% compared to 24.8%) during pregnancy. The majority first engaged with maternity services within their first trimester of pregnancy (63.5% compared to 84.4%). Babies were more likely to be born preterm (14.2% compared to 6.7%) and, for full-term babies, to have low birthweights (8.0% compared to 2.8%). Conclusion: This novel linkage study highlights multiple vulnerabilities experienced by pregnant mothers who have experienced care proceedings concerning an infant. Policy and practice colleagues require a clearer picture of women’s needs if child protection and health services are to offer effective services which prevent the need for family court proceedings and infant removal
Quasifree kaon-photoproduction from nuclei in a relativistic approach
We compute the recoil polarization of the lambda-hyperon and the photon
asymmetry for the quasifree photoproduction of kaons in a relativistic
impulse-approximation approach. Our motivation for studying polarization
observables is threefold. First, polarization observables are more effective
discriminators of subtle dynamics than the unpolarized cross section. Second,
earlier nonrelativistic calculations suggest an almost complete insensitivity
of polarization observables to distortions effects. Finally, this insensitivity
entails an enormous simplification in the theoretical treatment. Indeed, by
introducing the notion of a ``bound-nucleon propagator'' we exploit Feynman's
trace techniques to develop closed-form, analytic expressions for all
photoproduction observables. Moreover, our results indicate that polarization
observables are also insensitive to relativistic effects and to the nuclear
target. Yet, they are sensitive to the model parameters, making them ideal
tools for the study of modifications to the elementary amplitude --- such as in
the production, propagation, and decay of nucleon resonances --- in the nuclear
medium.Comment: 15 pages and 6 figures - submitted to PR
Quantum circuits for spin and flavor degrees of freedom of quarks forming nucleons
We discuss the quantum-circuit realization of the state of a nucleon in the
scope of simple symmetry groups. Explicit algorithms are presented for the
preparation of the state of a neutron or a proton as resulting from the
composition of their quark constituents. We estimate the computational
resources required for such a simulation and design a photonic network for its
implementation. Moreover, we highlight that current work on three-body
interactions in lattices of interacting qubits, combined with the
measurement-based paradigm for quantum information processing, may also be
suitable for the implementation of these nucleonic spin states.Comment: 5 pages, 2 figures, RevTeX4; Accepted for publication in Quantum
Information Processin
High-field magnetization study of the S = 1/2 antiferromagnetic Heisenberg chain [PM Cu(NO)(HO)] with a field-induced gap
We present a high-field magnetization study of the = 1/2
antiferromagnetic Heisenberg chain [PM Cu(NO)(HO)]. For
this material, as result of the Dzyaloshinskii-Moriya interaction and a
staggered tensor, the ground state is characterized by an anisotropic
field-induced spin excitation gap and a staggered magnetization. Our data
reveal the qualitatively different behavior in the directions of maximum and
zero spin excitation gap. The data are analyzed via exact diagonalization of a
linear spin chain with up to 20 sites and on basis of the Bethe ansatz
equations, respectively. For both directions we find very good agreement
between experimental data and theoretical calculations. We extract the magnetic
coupling strength along the chain direction to 36.3(5) K and determine
the field dependence of the staggered magnetization component .Comment: 5 pages, 2 figures (minor changes to manuscript and figures
Mirror Manifolds in Higher Dimension
We describe mirror manifolds in dimensions different from the familiar case
of complex threefolds. We emphasize the simplifying features of dimension three
and supply more robust methods that do not rely on such special characteristics
and hence naturally generalize to other dimensions. The moduli spaces for
Calabi--Yau -folds are somewhat different from the ``special K\"ahler
manifolds'' which had occurred for , and we indicate the new geometrical
structures which arise. We formulate and apply procedures which allow for the
construction of mirror maps and the calculation of order-by-order instanton
corrections to Yukawa couplings. Mathematically, these corrections are expected
to correspond to calculating Chern classes of various parameter spaces (Hilbert
schemes) for rational curves on Calabi--Yau manifolds. Our results agree with
those obtained by more traditional mathematical methods in the limited number
of cases for which the latter analysis can be carried out. Finally, we make
explicit some striking relations between instanton corrections for various
Yukawa couplings, derived from the associativity of the operator product
algebra.Comment: 44 pages plus 3 tables using harvma
Conformal Field Theories in Six-Dimensional Twistor Space
This article gives a study of the higher-dimensional Penrose transform
between conformally invariant massless fields on space-time and cohomology
classes on twistor space, where twistor space is defined to be the space of
projective pure spinors of the conformal group. We focus on the 6-dimensional
case in which twistor space is the six-quadric Q in CP^7 with a view to
applications to the self-dual (0,2)-theory. We show how spinor-helicity
momentum eigenstates have canonically defined distributional representatives on
twistor space (a story that we extend to arbitrary dimension). These give an
elementary proof of the surjectivity of the Penrose transform. We give a direct
construction of the twistor transform between the two different representations
of massless fields on twistor space (H^2 and H^3) in which the H^3s arise as
obstructions to extending the H^2s off Q into CP^7.
We also develop the theory of Sparling's `\Xi-transform', the analogous
totally real split signature story based now on real integral geometry where
cohomology no longer plays a role. We extend Sparling's \Xi-transform to all
helicities and homogeneities on twistor space and show that it maps kernels and
cokernels of conformally invariant powers of the ultrahyperbolic wave operator
on twistor space to conformally invariant massless fields on space-time. This
is proved by developing the 6-dimensional analogue of the half-Fourier
transform between functions on twistor space and momentum space. We give a
treatment of the elementary conformally invariant \Phi^3 amplitude on twistor
space and finish with a discussion of conformal field theories in twistor
space.Comment: 37 pages, 3 figures, in v2 a number of inaccuracies are removed and
the discussion is improved; in v3, one reference added;v4 extra
acknowledgemen
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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