113 research outputs found

    Hypertension prevalence and awareness in older Irish adults: Evidence from the Irish Longitudinal Study on Ageing (TILDA)

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    Introduction: Hypertension prevalence is increasing worldwide: population ageing and an increase in the prevalence of obesity are contributing to this rise. Hypertension is a major modifiable risk factor for stroke, coronary heart disease, end stage renal disease and has been associated with cognitive impairment. The aim of this study is to determine the prevalence of hypertension and to identify determinants of awareness of hypertension in older Irish adults. Methods: The Irish Longitudinal Study on Ageing (TILDA) is a population based prospective cohort study representative of community living adults. Each member of the Irish population aged 50 years and older had an equal probability of participation in the study. Face to face interviews and objective health assessments were conducted between Oct 2009 and July 2011. Descriptive statistics and logistic regression analysis were used to calculate prevalence and determinants of awareness of hypertension. Survey weights were applied to the estimates to adjust for selection and non-response bias in the survey. Results: The household response rate was 62%. Of the 8,175 respondents who took part in the study 5857 (71.6%) completed a comprehensive health assessment including blood pressure measurement. Hypertension was defined as a mean systolic blood pressure (SBP) ≄140mmHg and/or a mean diastolic blood pressure (DBP) ≄90mmHg and/or currently taking antihypertensive medications. The overall prevalence of hypertension was 64% (95% CI 62-65%) in those aged 50 years and older. Hypertension prevalence was higher in men than in women (69% vs 59%, p<.007) and prevalence increased with age to 87% (95% CI 84-89%) in those aged 75 years and older. Of those classified as hypertensive 55% (95% CI 53-57%) self-reported a previous doctor’s diagnosis of hypertension. Strong determinants of awareness included older age, female sex, overweight and obesity. Conclusions: This study documents a high prevalence of hypertension in adults aged 50 years and older in Ireland and identifies a low level of awareness of hypertension in this group. Raising awareness of hypertension is a major public health challenge. These findings provide reliable information which can contribute to practice and policy aimed at decreasing the prevalence of hypertension

    A comparative high-resolution study of predissociation linewidths in the Schumann-Runge bands of O2

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    Results are presented of a comparative study in which three distinct high-resolution experimental techniques (vacuum-ultraviolet laser spectroscopy, laser-induced fluorescence spectroscopy and vacuum-ultraviolet Fourier-transform spectroscopy) were used to study predissociation in the Schumann-Runge bands of O2 B 3Σ⎯u(vâ€Č)←X 3Σ⎯g(v″) with vâ€Č=13 and 14. Our measurements are the first to be performed at high resolution for these levels and represent a significant advance on previous knowledge, characterizing completely the fine-structure and rotation dependencies of the B 3Σ⎯u(v=13 and 14)-state predissociation for the first time. The measured fine-structurespecific linewidths will result in significant improvements in the parameterization of models describing predissociation of the B-state and will have an impact on the development of realistic photochemical models of the terrestrial atmosphere. Good agreement was found between linewidths measured using vacuum-ultraviolet laser spectroscopy and laser-induced fluorescence spectroscopy, but unexpected difficulties arose in determining quantitative linewidths using vacuum-ultraviolet Fourier-transform spectroscopy. For each experimental technique, the instrumental resolution had to be carefully controlled and monitored in order to ensure reliable interpretation of the measured spectra.The collaborative aspects of this research have been partially supported by reciprocal U.S.-Australian Cooperative Research Grants provided by the National Science Foundation ~U.S.! and the Department of Industry, Technology and Commerce ~Australia!. The measurements at SRI International were partially supported by grants from the Atmospheric Sciences Division of NSF and from the Stratospheric Chemistry Division of NASA. The measurements at the Photon Factory were supported in part by a NSF Division of Atmospheric Sciences Grant No. ATM-91-16552 to Harvard College Observatory, and by the NASA Upper Atmospheric Research Program under Grant No. NAG5-484 to the Smithsonian Astrophysical Observatory. We also acknowledge the support of the Paul Instrument Fund of the Royal Society for the development of the VUV-FT spectrometer. The FTS measurements were made with the approval of the Photon Factory Advisory Committee ~94G367!. K.Y. thanks the Japan Society for the Promotion of Science for support

    Kaon-Nucleon Scattering Amplitudes and Z∗^*-Enhancements from Quark Born Diagrams

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    We derive closed form kaon-nucleon scattering amplitudes using the ``quark Born diagram" formalism, which describes the scattering as a single interaction (here the OGE spin-spin term) followed by quark line rearrangement. The low energy I=0 and I=1 S-wave KN phase shifts are in reasonably good agreement with experiment given conventional quark model parameters. For klab>0.7k_{lab}> 0.7 Gev however the I=1 elastic phase shift is larger than predicted by Gaussian wavefunctions, and we suggest possible reasons for this discrepancy. Equivalent low energy KN potentials for S-wave scattering are also derived. Finally we consider OGE forces in the related channels KΔ\Delta, K∗^*N and K∗Δ^*\Delta, and determine which have attractive interactions and might therefore exhibit strong threshold enhancements or ``Z∗^*-molecule" meson-baryon bound states. We find that the minimum-spin, minimum-isospin channels and two additional K∗Δ^*\Delta channels are most conducive to the formation of bound states. Related interesting topics for future experimental and theoretical studies of KN interactions are also discussed.Comment: 34 pages, figures available from the authors, revte

    NN Core Interactions and Differential Cross Sections from One Gluon Exchange

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    We derive nonstrange baryon-baryon scattering amplitudes in the nonrelativistic quark model using the ``quark Born diagram" formalism. This approach describes the scattering as a single interaction, here the one-gluon-exchange (OGE) spin-spin term followed by constituent interchange, with external nonrelativistic baryon wavefunctions attached to the scattering diagrams to incorporate higher-twist wavefunction effects. The short-range repulsive core in the NN interaction has previously been attributed to this spin-spin interaction in the literature; we find that these perturbative constituent-interchange diagrams do indeed predict repulsive interactions in all I,S channels of the nucleon-nucleon system, and we compare our results for the equivalent short-range potentials to the core potentials found by other authors using nonperturbative methods. We also apply our perturbative techniques to the NΔ\Delta and ΔΔ\Delta\Delta systems: Some ΔΔ\Delta\Delta channels are found to have attractive core potentials and may accommodate ``molecular" bound states near threshold. Finally we use our Born formalism to calculate the NN differential cross section, which we compare with experimental results for unpolarised proton-proton elastic scattering. We find that several familiar features of the experimental differential cross section are reproduced by our Born-order result.Comment: 27 pages, figures available from the authors, revtex, CEBAF-TH-93-04, MIT-CTP-2187, ORNL-CCIP-93-0

    Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

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    We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society

    Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

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    The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

    All-sky search for long-duration gravitational wave transients with initial LIGO

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    We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

    Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

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    [no abstract available

    All-sky search for long-duration gravitational wave transients with initial LIGO

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    We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

    Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b

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    We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society
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