3,221 research outputs found

    CMB Lensing Power Spectrum Biases from Galaxies and Clusters using High-angular Resolution Temperature Maps

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    The lensing power spectrum from cosmic microwave background (CMB) temperature maps will be measured with unprecedented precision with upcoming experiments, including upgrades to ACT and SPT. Achieving significant improvements in cosmological parameter constraints, such as percent level errors on sigma_8 and an uncertainty on the total neutrino mass of approximately 50 meV, requires percent level measurements of the CMB lensing power. This necessitates tight control of systematic biases. We study several types of biases to the temperature-based lensing reconstruction signal from foreground sources such as radio and infrared galaxies and the thermal Sunyaev-Zel'dovich effect from galaxy clusters. These foregrounds bias the CMB lensing signal due to their non-Gaussian nature. Using simulations as well as some analytical models we find that these sources can substantially impact the measured signal if left untreated. However, these biases can be brought to the percent level if one masks galaxies with fluxes at 150 GHz above 1 mJy and galaxy clusters with masses above M_vir = 10^14 M_sun. To achieve such percent level bias, we find that only modes up to a maximum multipole of l_max ~ 2500 should be included in the lensing reconstruction. We also discuss ways to minimize additional bias induced by such aggressive foreground masking by, for example, exploring a two-step masking and in-painting algorithm.Comment: 14 pages, 14 figures, to be submitted to Ap

    Self-monitoring for improving control of blood pressue in patients with hypertension

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    The objective of this review is to determine the effect of SBPM in adults with hypertension on blood pressure control as compared to OBPM or usual care

    Promoting the achievement of looked after children and young people across Cardiff

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    As of March 2017, there were 5,955 children and young people in care in Wales. Across the Central South Consortium (Bridgend, Cardiff, Merthyr Tydfil, Rhondda Cynonn Taf and Vale of Glamorgan) there were 2,170 children and young people looked after. The majority of these children are in care as a result of birth families being unable to provide a level of care that meets their emotional and well-being needs. Children and young people who are in or have experienced care remain one of the lowest performing groups in terms of educational outcomes. In 2016, eleven per cent of young people in Wales achieved A* to C grade at GCSE. Care leavers can experience poorer employment and health outcomes after leaving school compared to their peers; for example, 45% of young people who were looked after were not engaged in education, training or employment (NEET) or not in touch with their local authority on their 19th birthday in 2015. This compares with around 4.9% of all other children who leave school at the end of Year 13. However, the education and achievement of children and young people in care is currently the focus of renewed policy, research and practice attention across Wales. The Social Services and Wellbeing (Wales) Act 2014 provides the legal framework for improving the well-being of people who need care and support. A national strategic approach to improving outcomes for children looked after is underway with a focus on promoting and improving collaborative working across agencies, identifying and sharing good practice and making improvements where they are needed. The purpose of this report is to share practice in selected in Cardiff schools that is contributing to improved outcomes and school experiences for children and young people in care

    Zebrafish cerebrospinal fluid mediates cell survival through a retinoid signaling pathway

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    Cerebrospinal fluid (CSF) includes conserved factors whose function is largely unexplored. To assess the role of CSF during embryonic development, CSF was repeatedly drained from embryonic zebrafish brain ventricles soon after their inflation. Removal of CSF increased cell death in the diencephalon, indicating a survival function. Factors within the CSF are required for neuroepithelial cell survival as injected mouse CSF but not artificial CSF could prevent cell death after CSF depletion. Mass spectrometry analysis of the CSF identified retinol binding protein 4 (Rbp4), which transports retinol, the precursor to retinoic acid (RA). Consistent with a role for Rbp4 in cell survival, inhibition of Rbp4 or RA synthesis increased neuroepithelial cell death. Conversely, ventricle injection of exogenous human RBP4 plus retinol, or RA alone prevented cell death after CSF depletion. Zebrafish rbp4 is highly expressed in the yolk syncytial layer, suggesting Rbp4 protein and retinol/RA precursors can be transported into the CSF from the yolk. In accord with this suggestion, injection of human RBP4 protein into the yolk prevents neuroepithelial cell death in rbp4 loss-of-function embryos. Together, these data support the model that Rbp4 and RA precursors are present within the CSF and used for synthesis of RA, which promotes embryonic neuroepithelial survival

    Promoting the achievement of looked after children and young people across the Central South Consortium in Wales

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    As of March 2017, there were 5,955 children and young people in care in Wales. Across the Central South Consortium (Bridgend, Cardiff, Merthyr Tydfil, Rhondda Cynonn Taf and Vale of Glamorgan) there were 2,170 children and young people looked after. The majority of these children are in care as a result of birth families being unable to provide a level of care that meets their emotional and well-being needs. Children and young people who are in or have experienced care remain one of the lowest performing groups in terms of educational outcomes. In 2016, eleven per cent of young people in Wales achieved A* to C grade at GCSE. Care leavers can experience poorer employment and health outcomes after leaving school compared to their peers; for example, 45% of young people who were looked after were not engaged in education, training or employment (NEET) or not in touch with their local authority on their 19th birthday in 2015. This compares with around 4.9% of all other children who leave school at the end of Year 13. However, the education and achievement of children and young people in care is currently the focus of renewed policy, research and practice attention across Wales. The Social Services and Wellbeing (Wales) Act 2014 provides the legal framework for improving the well-being of people who need care and support. A national strategic approach to improving outcomes for children looked after is underway with a focus on promoting and improving collaborative working across agencies, identifying and sharing good practice and making improvements where they are needed. The purpose of this report is to share practice in selected in Central South Consortium (CSC) schools that is contributing to improved outcomes and school experiences for children and young people in care

    The polarizability model for ferroelectricity in perovskite oxides

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    This article reviews the polarizability model and its applications to ferroelectric perovskite oxides. The motivation for the introduction of the model is discussed and nonlinear oxygen ion polarizability effects and their lattice dynamical implementation outlined. While a large part of this work is dedicated to results obtained within the self-consistent-phonon approximation (SPA), also nonlinear solutions of the model are handled which are of interest to the physics of relaxor ferroelectrics, domain wall motions, incommensurate phase transitions. The main emphasis is to compare the results of the model with experimental data and to predict novel phenomena.Comment: 55 pages, 35 figure

    A flexible low-cost, high-precision, single interface electrical impedance tomography system for breast cancer detection using FPGA

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    Typically, in multi-frequency Electrical Impedance Tomography (EIT) systems, a current is applied and the voltages developed across the subject are detected. However, due to the complexity of designing stable current sources, there has been mention in the literature of applying a voltage to the subject whilst measuring the consequent current flow. This paper presents a comparative study between the two techniques in a novel design suitable for the detection of breast cancers. The suggested instrument borrows the best features of both the injection of current and the application of voltage, circumventing their limitations. Furthermore, the system has a common patient-electrode interface for both methodologies, whilst the control of the system and the necessary signal processing is carried out in a field programmable gate array (FPGA). Through this novel system, wide-bandwidth, low-noise, as well as high-speed (frame rate) can be achieved

    Exercise to preserve beta cell function in recent-onset type 1 diabetes mellitus (EXTOD) - a study protocol for a pilot randomized controlled trial

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    BACKGROUND: Exercise has a beta cell preserving effect in patients with type 2 diabetes. This benefit of exercise has not been examined in type 1 diabetes. Significant beta cell function is present at the time of diagnosis of type 1 diabetes and therefore studies of beta cell preservation are ideally conducted immediately after diagnosis.Many of the variables required to design and power such a study are currently unknown. The aim of EXTOD is to obtain the information required to design a formal study of exercise and beta cell preservation in newly diagnosed patients with type 1 diabetes. METHODS: Barriers to exercise will initially be assessed in a qualitative study of newly diagnosed patients. Then, sixty newly diagnosed adult type 1 diabetes patients will be randomized to either conventional treatment or exercise, stratified on beta cell function and fitness. The exercise group will be encouraged to increase their level of activity to a minimum of 150 minutes of moderate to vigorous intensity exercise per week, aiming for 240 minutes per week of exercise for 12 months. Beta cell function will be measured by meal-stimulated C peptide. Primary outcomes are recruitment, adherence to exercise, loss to follow-up, and exercise levels in the non-intervention arm (contamination). The secondary outcome of the study is rate of loss of beta cell function. DISCUSSION: The outcomes of the EXTOD study will help define the barriers, uptake and benefits of exercise in adults newly diagnosed with type 1 diabetes. This information will enable design of a formal study to assess the effect of exercise on beta cell preservation in newly diagnosed patients with type 1 diabetes. TRIAL REGISTRATION: Current controlled trials ISRCTN91388505.Funding is provided by the Research for Patient Benefit (RfPB) stream of the National Institute for Health Research UK

    Weighing Obscured and Unobscured Quasar Hosts with the Cosmic Microwave Background

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    We cross-correlate a cosmic microwave background (CMB) lensing map with the projected space densities of quasars to measure the bias and halo masses of a quasar sample split into obscured and unobscured populations, the first application of this method to distinct quasar subclasses. Several recent studies of the angular clustering of obscured quasars have shown that these objects likely reside in higher-mass halos compared to their unobscured counterparts. This has important implications for models of the structure and geometry of quasars, their role in growing supermassive black holes, and mutual quasar/host galaxy evolution. However, the magnitude and significance of this difference has varied from study to study. Using data from \planck, \wise, and SDSS, we follow up on these results using the independent method of CMB lensing cross-correlations. The region and sample are identical to that used for recent angular clustering measurements, allowing for a direct comparison of the CMB-lensing and angular clustering methods. At z∼1, we find that the bias of obscured quasars is bq=2.57±0.24, while that of unobscured quasars is bq=1.89±0.19. This corresponds to halo masses of log(Mh/M⊙h−1)=13.24+0.14−0.15 (obscured) and log(Mh/M⊙h−1)=12.71+0.15−0.13 (unobscured). These results agree well with with those from angular clustering (well within 1σ), and confirm that obscured quasars reside in host halos ∼3 times as massive as halos hosting unobscured quasars. This implies that quasars spend a significant portion of their lifetime in an obscured state, possibly more than one half of the entire active phase

    Ab initio phonon dispersion curves and interatomic force constants of barium titanate

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    The phonon dispersion curves of cubic BaTiO_3 have been computed within a first-principles approach and the results compared to the experimental data. The curves obtained are very similar to those reported for KNbO_3 by Yu and Krakauer [Phys. Rev. Lett. 74, 4067 (1995)]. They reveal that correlated atomic displacements along chains are at the origin of the ferroelectric instability. A simplified model illustrates that spontaneous collective displacements will occur when a dozen of aligned atoms are coupled. The longitudinal interatomic force constant between nearest neighbour Ti and O atoms is relatively weak in comparison to that between Ti atoms in adjacent cells. The small coupling between Ti and O displacements seems however necessary to reproduce a ferroelectric instability.Comment: 12 pages, 4 figure
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