1,687 research outputs found

    Adverse childhood experiences during childhood and academic attainment at age 7 and 11 years: an electronic birth cohort study

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    Objectives Adverse childhood experiences (ACEs) have a negative impact on childhood health, but their impact on education outcomes is less well known. We investigated whether or not ACEs were associated with reduced educational attainment at age 7 and 11 years. Study design The study design used in the study is a population-based electronic cohort study. Methods We analysed data from a total population electronic child cohort in Wales, UK. ACEs (exposures) were living with an adult household member with any of (i) serious mental illness, (ii) common mental disorder (CMD), (iii) an alcohol problem; (iv) child victimisation, (v) death of a household member and (vi) low family income. We used multilevel logistic regression to model exposure to these ACEs and not attaining the expected level at statutory education assessments, Key Stage (KS) 1 and KS2 separately, adjusted for known confounders including perinatal, socio-economic and school factors. Results There were 107,479 and 43,648 children included in the analysis, with follow-up to 6–7 years (KS1) and 10–11 years (KS2), respectively. An increased risk of not attaining the expected level at KS1 was associated with living with adult household members with CMD (adjusted odds ratio [aOR]: 1.13 [95% confidence interval [CI]: 1.09–1.17]) or an alcohol problem (adjusted odds ratio [aOR]: 1.16 [95% confidence interval [CI]: 1.10–1.22]), childhood victimisation (adjusted odds ratio [aOR]: 1.58 [95% confidence interval [CI]: 1.37–1.82]), death of a household member (adjusted odds ratio [aOR]: 1.14 [95% confidence interval [CI]: 1.04–1.25]) and low family income (adjusted odds ratio [aOR]: 1.92 [95% confidence interval [CI]: 1.84–2.01]). Similar results were observed for KS2. Children with multiple adversities had substantially increased odds of not attaining the expected level at each educational assessment. Conclusion The educational potential of many children may not be achieved due to exposure to adversity in childhood. Affected children who come in to contact with services should have relevant information shared between health and care services, and schools to initiate and facilitate a coordinated approach towards providing additional support and help for them to fulfil their educational potential, and subsequent economic and social participation

    The Landau Pole and Zâ€ČZ^{\prime} decays in the 331 bilepton model

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    We calculate the decay widths and branching ratios of the extra neutral boson Zâ€ČZ^{\prime} predicted by the 331 bilepton model in the framework of two different particle contents. These calculations are performed taken into account oblique radiative corrections, and Flavor Changing Neutral Currents (FCNC) under the ansatz of Matsuda as a texture for the quark mass matrices. Contributions of the order of 10−1−10−210^{-1}-10^{-2} are obtained in the branching ratios, and partial widths about one order of magnitude bigger in relation with other non- and bilepton models are also obtained. A Landau-like pole arise at 3.5 TeV considering the full particle content of the minimal model (MM), where the exotic sector is considered as a degenerated spectrum at 3 TeV scale. The Landau pole problem can be avoid at the TeV scales if a new leptonic content running below the threshold at % 3 TeV is implemented as suggested by other authors.Comment: 20 pages, 5 figures, LaTeX2

    Stability of the Scalar Potential and Symmetry Breaking in the Economical 3-3-1 Model

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    A detailed study of the criteria for stability of the scalar potential and the proper electroweak symmetry breaking pattern in the economical 3-3-1 model, is presented. For the analysis we use, and improve, a method previously developed to study the scalar potential in the two-Higgs-doublet extension of the standard model. A new theorem related to the stability of the potential is stated. As a consequence of this study, the consistency of the economical 3-3-1 model emerges.Comment: to be published in EPJ C, 13 page

    Facility for studying the effects of elevated carbon dioxide concentration and increased temperature on crops

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    The requirements for the experimental study of the effects of global climate change conditions on plants are outlined. A semi-controlled plant growth facility is described which allows the study of elevated CO2 and temperature, and their interaction on the growth of plants under radiation and temperature conditions similar to the field. During an experiment on winter wheat (cv. Mercia), which ran from December 1990 through to August 1991, the facility maintained mean daytime CO2 concentrations of 363 and 692 cm3 m-3 for targets of 350 and 700 cm3 m-3 respectively. Temperatures were set to follow outside ambient or outside ambient +4-degrees-C, and hourly means were within 0.5-degrees-C of the target for 92% of the time for target temperatures greater than 6-degrees-C. Total photosynthetically active radiation incident on the crop (solar radiation supplemented by artifical light with natural photoperiod) was 2% greater than the total measured outside over the same period

    Chromomagnetic Dipole Moment of the Top Quark Revisited

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    We study the complete one-loop contributions to the chromagnetic dipole moment ΔÎș\Delta\kappa of the top quark in the Standard Model, two Higgs doublet models, topcolor assited technicolor models (TC2), 331 models and extended models with a single extra dimension. We find that the SM predicts ΔÎș=−0.056\Delta\kappa = - 0.056 and that the predictions of the other models are also consitent with the constraints imposed on ΔÎș\Delta\kappa by low-energy precision measurements.Comment: 20 pages, 5 figures, Updat

    Guiding the Way to Gamma-Ray Sources: X-ray Studies of Supernova Remnants

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    Supernova remnants have long been suggested as a class of potential counterparts to unidentified gamma-ray sources. The mechanisms by which such gamma-rays can arise may include emission from a pulsar associated with a remnant, or a variety of processes associated with energetic particles accelerated by the SNR shock. Imaging and spectral observations in the X-ray band can be used to identify properties of the remnants that lead to gamma-ray emission, including the presence of pulsar-driven nebulae, nonthermal X-ray emission from the SNR shells, and the interaction of SNRs with dense surrounding material.Comment: 16 pages, 11 figures, To appear in the proceedings of the workshop: "The Nature of the Unidentified Galactic Gamma-Ray Sources" held at INAOE, Mexico, October 2000, (A.Carraminana, O. Reiner and D. Thompson, eds.

    New evidence for strong nonthermal effects in Tycho's supernova remnant

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    For the case of Tycho's supernova remnant (SNR) we present the relation between the blast wave and contact discontinuity radii calculated within the nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is demonstrated that these radii are confirmed by recently published Chandra measurements which show that the observed contact discontinuity radius is so close to the shock radius that it can only be explained by efficient CR acceleration which in turn makes the medium more compressible. Together with the recently determined new value Esn=1.2×1051E_{sn}=1.2\times 10^{51} erg of the SN explosion energy this also confirms our previous conclusion that a TeV gamma-ray flux of (2−5)×10−13(2-5)\times 10^{-13} erg/(cm2^2s) is to be expected from Tycho's SNR. Chandra measurements and the HEGRA upper limit of the TeV gamma-ray flux together limit the source distance dd to 3.3≀d≀43.3\leq d\leq 4 kpc.Comment: 5 pages, 4 figures. Accepted for publication in Astrophysics and Space Science, Proc. of "The Multi-Messenger Approach to High-Energy Gamma-ray Sources (Third Workshop on the Nature of Unidentified High-Energy Sources)", Barcelona, July 4-7, 200

    On the spherical-axial transition in supernova remnants

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    A new law of motion for supernova remnant (SNR) which introduces the quantity of swept matter in the thin layer approximation is introduced. This new law of motion is tested on 10 years observations of SN1993J. The introduction of an exponential gradient in the surrounding medium allows to model an aspherical expansion. A weakly asymmetric SNR, SN1006, and a strongly asymmetric SNR, SN1987a, are modeled. In the case of SN1987a the three observed rings are simulated.Comment: 19 figures and 14 pages Accepted for publication in Astrophysics & Space Science in the year 201

    Cross-sectional and longitudinal voxel-based grey matter asymmetries in Huntington's disease

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    Huntington's disease (HD) is a progressive neurodegenerative disorder that can be genetically confirmed with certainty decades before clinical onset. This allows the investigation of functional and structural changes in HD many years prior to disease onset, which may reveal important mechanistic insights into brain function, structure and organization in general. While regional atrophy is present at early stages of HD, it is still unclear if both hemispheres are equally affected by neurodegeneration and how the extent of asymmetry affects domain-specific functional decline. Here, we used whole-brain voxel-based analysis to investigate cross-sectional and longitudinal hemispheric asymmetries in grey matter (GM) volume in 56 manifest HD (mHD), 83 pre-manifest HD (preHD), and 80 healthy controls (HC). Furthermore, a regression analysis was used to assess the relationship between neuroanatomical asymmetries and decline in motor and cognitive measures across the disease spectrum. The cross-sectional analysis showed striatal leftward-biased GM atrophy in mHD, but not in preHD, relative to HC. Longitudinally, no net 36-month change in GM asymmetries was found in any of the groups. In the regression analysis, HD-related decline in quantitative-motor (Q-Motor) performance was linked to lower GM volume in the left superior parietal cortex. These findings suggest a stronger disease effect targeting the left hemisphere, especially in those with declining motor performance. This effect did not change over a period of three years and may indicate a compensatory role of the right hemisphere in line with recent functional imaging studies

    The spectral gap for some spin chains with discrete symmetry breaking

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    We prove that for any finite set of generalized valence bond solid (GVBS) states of a quantum spin chain there exists a translation invariant finite-range Hamiltonian for which this set is the set of ground states. This result implies that there are GVBS models with arbitrary broken discrete symmetries that are described as combinations of lattice translations, lattice reflections, and local unitary or anti-unitary transformations. We also show that all GVBS models that satisfy some natural conditions have a spectral gap. The existence of a spectral gap is obtained by applying a simple and quite general strategy for proving lower bounds on the spectral gap of the generator of a classical or quantum spin dynamics. This general scheme is interesting in its own right and therefore, although the basic idea is not new, we present it in a system-independent setting. The results are illustrated with an number of examples.Comment: 48 pages, Plain TeX, BN26/Oct/9
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