536 research outputs found

    Socio-demographic characteristics, lifestyle factors and burden of morbidity associated with self-reported hearing and vision impairments in older British community-dwelling men: a cross-sectional study.

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    BACKGROUND: Hearing and vision problems are common in older adults. We investigated the association of self-reported sensory impairment with lifestyle factors, chronic conditions, physical functioning, quality of life and social interaction. METHODS: A population-based cross-sectional study of participants of the British Regional Heart Study aged 63-85 years. RESULTS: A total of 3981 men (82% response rate) provided data. Twenty-seven per cent (n = 1074) reported hearing impairment including being able to hear with aid (n = 482), being unable to hear (no aid) (n = 424) and being unable to hear despite aid (n = 168). Three per cent (n = 124) reported vision impairment. Not being able to hear, irrespective of use of hearing aid, was associated with poor quality of life, poor social interaction and poor physical functioning. Men who could not hear despite hearing aid were more likely to report coronary heart disease (CHD) [age-adjusted odds ratios (ORs) 1.89 (95% confidence interval 1.36-2.63)]. Vision impairment was associated with symptoms of CHD including breathlessness [OR 2.06 (1.38-3.06)] and chest pain [OR 1.58 (1.07-2.35)]. Vision impairment was also associated with poor quality of life, poor social interaction and poor physical functioning. CONCLUSIONS: Sensory impairment is associated with poor physical functioning, poor health and poor social interaction in older men. Further research is warranted on pathways underlying these associations

    Operationalizing Human Immunodeficiency Virus Cure-related Trials with Analytic Treatment Interruptions During the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Pandemic: A Collaborative Approach

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    Efforts to recognize and minimize the risk to study participants will be necessary to safely and ethically resume scientific research in the context of the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. These efforts are uniquely challenging in the context of human immunodeficiency virus (HIV) cure clinical trials, which often involve complex experimental therapy regimens and perhaps analytic treatment interruption, in which participants pause antiretroviral therapy. In this viewpoint, we discuss our approach to reopening an HIV cure trial in this context, with a focus on key considerations regarding study design, informed consent and participant education, and study implementation. These recommendations might be informative to other groups seeking to resume HIV cure research in settings similar to ours

    Laser ablation loading of a radiofrequency ion trap

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    The production of ions via laser ablation for the loading of radiofrequency (RF) ion traps is investigated using a nitrogen laser with a maximum pulse energy of 0.17 mJ and a peak intensity of about 250 MW/cm^2. A time-of-flight mass spectrometer is used to measure the ion yield and the distribution of the charge states. Singly charged ions of elements that are presently considered for the use in optical clocks or quantum logic applications could be produced from metallic samples at a rate of the order of magnitude 10^5 ions per pulse. A linear Paul trap was loaded with Th+ ions produced by laser ablation. An overall ion production and trapping efficiency of 10^-7 to 10^-6 was attained. For ions injected individually, a dependence of the capture probability on the phase of the RF field has been predicted. In the experiment this was not observed, presumably because of collective effects within the ablation plume.Comment: submitted to Appl. Phys. B., special issue on ion trappin

    Polymer-Layered Silicate Nanocomposites for Cryotank Applications

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    Previous composite cryotank designs have relied on the use of conventional composite materials to reduce microcracking and permeability. However, revolutionary advances in nanotechnology derived materials may enable the production of ultra-lightweight cryotanks with significantly enhanced durability and damage tolerance, as well as reduced propellant permeability. Layered silicate nanocomposites are especially attractive in cryogenic storage tanks based on results that have been reported for epoxy nanocomposite systems. These materials often exhibit an order of magnitude reduction in gas permeability when compared to the base resin. In addition, polymer-silicate nanocomposites have been shown to yield improved dimensional stability, strength, and toughness. The enhancement in material performance of these systems occurs without property trade-offs which are often observed in conventionally filled polymer composites. Research efforts at NASA Glenn Research Center have led to the development of epoxy-clay nanocomposites with 70% lower hydrogen permeability than the base epoxy resin. Filament wound carbon fiber reinforced tanks made with this nanocomposite had a five-fold lower helium leak rate than the corresponding tanks made without clay. The pronounced reduction observed with the tank may be due to flow induced alignment of the clay layers during processing. Additionally, the nanocomposites showed CTE reductions of up to 30%, as well as a 100% increase in toughness

    SARS-CoV-2 Vaccination in the Context of Ongoing HIV Cure-Related Research Studies

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    To the Editors: The SARS-CoV-2 pandemic has affected research efforts worldwide. Previously, we described our strategy to mitigate COVID-19 transmission risk during an ongoing HIV cure-related clinical trial. SARS-CoV-2 vaccines recently have been authorized for emergency use and will become available to people with HIV imminently. As a result, researchers must determine how to adjust study protocols to incorporate the likelihood that participants may be vaccinated

    Long Distance Contribution to sdγs \to d\gamma and Implications for ΩΞγ,BsBdγ\Omega^-\to \Xi ^-\gamma, B_s \to B_d^*\gamma and bsγb \to s\gamma

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    We estimate the long distance (LD) contribution to the magnetic part of the sdγs \to d\gamma transition using the Vector Meson Dominance approximation (V=ρ,ω,ψi)(V=\rho,\omega,\psi_i). We find that this contribution may be significantly larger than the short distance (SD) contribution to sdγs \to d\gamma and could possibly saturate the present experimental upper bound on the ΩΞγ\Omega^-\to \Xi^-\gamma decay rate, ΓΩΞγMAX3.7×109\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma} \simeq 3.7\times10^{-9}eV. For the decay BsBdγB_s \to B^*_d\gamma, which is driven by sdγs \to d\gamma as well, we obtain an upper bound on the branching ratio BR(BsBdγ)<3×108BR(B_s \to B_d^*\gamma)<3\times10^{-8} from ΓΩΞγMAX\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma}. Barring the possibility that the Quantum Chromodynamics coefficient a2(ms)a_2(m_s) be much smaller than 1, ΓΩΞγMAX\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma} also implies the approximate relation 23igψi2(0)mψi212gρ2(0)mρ2+16gω2(0)mω2\frac{2}{3} \sum_i \frac{g^2_{\psi_i}(0)}{m^2_{\psi_i}} \simeq \frac{1}{2} \frac{g^2_\rho(0)}{m^2_\rho} + \frac{1}{6}\frac{g^2_\omega(0)}{m^2_\omega}. This relation agrees quantitatively with a recent independent estimate of the l.h.s. by Deshpande et al., confirming that the LD contributions to bsγb \to s\gamma are small. We find that these amount to an increase of (4±2)%(4\pm2)\% in the magnitude of the bsγb \to s \gamma transition amplitude, relative to the SD contribution alone.Comment: 16 pages, LaTeX fil

    Exclusive Higgs Boson Production with bottom quarks at Hadron Colliders

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    We present the next-to-leading order QCD corrected rate for the production of a scalar Higgs boson with a pair of high p_T bottom and anti-bottom quarks at the Tevatron and at the Large Hadron Collider. Results are given for both the Standard Model and the Minimal Supersymmetric Standard Model. The exclusive b-bbar-h production rate is small in the Standard Model, but it can be greatly enhanced in the Minimal Supersymmetric Standard Model for large tan(beta), making b-bbar-h an important discovery mode. We find that the next-to-leading order QCD results are much less sensitive to the renormalization and factorization scales than the lowest order results, but have a significant dependence on the choice of the renormalization scheme for the bottom quark Yukawa coupling.Comment: 27 pages, 17 figures, RevTeX

    Primordial nucleosynthesis with a varying fine structure constant: An improved estimate

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    We compute primordial light-element abundances for cases with fine structure constant alpha different from the present value, including many sources of alpha dependence neglected in previous calculations. Specifically, we consider contributions arising from Coulomb barrier penetration, photon coupling to nuclear currents, and the electromagnetic components of nuclear masses. We find the primordial abundances to depend more weakly on alpha than previously estimated, by up to a factor of 2 in the case of ^7Li. We discuss the constraints on variations in alpha from the individual abundance measurements and the uncertainties affecting these constraints. While the present best measurements of primordial D/H, ^4He/H, and ^7Li/H may be reconciled pairwise by adjusting alpha and the universal baryon density, no value of alpha allows all three to be accommodated simultaneously without consideration of systematic error. The combination of measured abundances with observations of acoustic peaks in the cosmic microwave background favors no change in alpha within the uncertainties.Comment: Phys. Rev. D accepted version; minor changes in response to refere

    Weight and age at weaning influence pancreatic size and enzymatic capacity

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    Many pig producers are moving towards early weaning in an effort to minimise disease transfer from sow to piglet. However, it is possible that the digestive function of early-weaned pigs may be immature and incapable of digesting many feedstuffs. The present study was designed to examine some of the factors that might influence pancreatic enzymic function in the weaned pig
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