179 research outputs found

    Public attitudes in England towards the sharing of personal data following a mass casualty incident : a cross-sectional study

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    Objectives: To assess public attitudes towards data sharing to facilitate a mental health screening programme for people caught up in a mass casualty incident. Design: Two, identical, cross-sectional, online surveys, using quotas to ensure demographic representativeness of people aged 18–65 years in England. Participants were randomly allocated to consider a scenario in which they witness a terrorism-related radiation incident or mass shooting, after which a police officer records their contact details. Setting: Participants were drawn from an online panel maintained by a market research company. Surveys were conducted before and immediately after a series of terrorist attacks and a large tower block fire occurred in England. Participants: One thousand people aged 18–65 years participated in each survey. Main outcome measures: Three questions asking participants if it would be acceptable for police to share their contact details, without asking first, with ‘a health-related government organisation, so they can send you a questionnaire to find out if you might benefit from extra care or support’, ‘a specialist NHS team, to provide you with information about ways to get support for any physical or mental health issues’ and ‘your GP, so they can check how you are doing’. Results: A minority of participants reported that it would be definitely not acceptable for their details to be shared with the government organisation (n=259, 13.0%), the National Health Service (NHS) (n=141, 7.1%) and their general practitioner (GP) (n=166, 8.3%). There was a small, but significant increase in acceptability for the radiation incident compared with the mass shooting. No major differences were observed between the preincident and postincident surveys. Conclusions: Although most people believe it is acceptable for their details to be shared in order to facilitate a mental health response to a major incident, care must be taken to communicate with those affected about how their information will be used

    Quantum diffraction and interference of spatially correlated photon pairs generated by spontaneous parametric down-conversion

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    We demonstrate one- and two-photon diffraction and interference experiments utilizing parametric down-converted photon pairs (biphotons) and a transmission grating. With two-photon detection, the biphoton exhibits a diffraction-interference pattern equivalent to that of an effective single particle that is associated with half the wavelength of the constituent photons. With one-photon detection, however no diffraction-interference pattern is observed. We show that these phenomena originate from the spatial quantum correlation between the down-converted photons.Comment: 4 pages, 5 figure

    Spectroscopy by frequency entangled photon pairs

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    Quantum spectroscopy was performed using the frequency-entangled broadband photon pairs generated by spontaneous parametric down-conversion. An absorptive sample was placed in front of the idler photon detector, and the frequency of signal photons was resolved by a diffraction grating. The absorption spectrum of the sample was measured by counting the coincidences, and the result is in agreement with the one measured by a conventional spectrophotometer with a classical light source.Comment: 11 pages, 5 figures, to be published in Phys. Lett.

    Reconstruction of the Dark Energy equation of state

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    One of the main challenges of modern cosmology is to investigate the nature of dark energy in our Universe. The properties of such a component are normally summarised as a perfect fluid with a (potentially) time-dependent equation-of-state parameter w(z)w(z). We investigate the evolution of this parameter with redshift by performing a Bayesian analysis of current cosmological observations. We model the temporal evolution as piecewise linear in redshift between `nodes', whose ww-values and redshifts are allowed to vary. The optimal number of nodes is chosen by the Bayesian evidence. In this way, we can both determine the complexity supported by current data and locate any features present in w(z)w(z). We compare this node-based reconstruction with some previously well-studied parameterisations: the Chevallier-Polarski-Linder (CPL), the Jassal-Bagla-Padmanabhan (JBP) and the Felice-Nesseris-Tsujikawa (FNT). By comparing the Bayesian evidence for all of these models we find an indication towards possible time-dependence in the dark energy equation-of-state. It is also worth noting that the CPL and JBP models are strongly disfavoured, whilst the FNT is just significantly disfavoured, when compared to a simple cosmological constant w=−1w=-1. We find that our node-based reconstruction model is slightly disfavoured with respect to the Λ\LambdaCDM model.Comment: 17 pages, 5 figures, minor correction

    Infinite systems of non-colliding generalized meanders and Riemann-Liouville differintegrals

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    Yor's generalized meander is a temporally inhomogeneous modification of the 2(ν+1)2(\nu+1)-dimensional Bessel process with ν>−1\nu > -1, in which the inhomogeneity is indexed by κ∈[0,2(ν+1))\kappa \in [0, 2(\nu+1)). We introduce the non-colliding particle systems of the generalized meanders and prove that they are the Pfaffian processes, in the sense that any multitime correlation function is given by a Pfaffian. In the infinite particle limit, we show that the elements of matrix kernels of the obtained infinite Pfaffian processes are generally expressed by the Riemann-Liouville differintegrals of functions comprising the Bessel functions JνJ_{\nu} used in the fractional calculus, where orders of differintegration are determined by ν−κ\nu-\kappa. As special cases of the two parameters (ν,κ)(\nu, \kappa), the present infinite systems include the quaternion determinantal processes studied by Forrester, Nagao and Honner and by Nagao, which exhibit the temporal transitions between the universality classes of random matrix theory.Comment: LaTeX, 35 pages, v3: The argument given in Section 3.2 was simplified. Minor corrections were mad

    Observational constraints on conformal time symmetry, missing matter and double dark energy

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    The current concordance model of cosmology is dominated by two mysterious ingredients: dark matter and dark energy. In this paper, we explore the possibility that, in fact, there exist two dark-energy components: the cosmological constant Λ\Lambda, with equation-of-state parameter wΛ=−1w_\Lambda=-1, and a `missing matter' component XX with wX=−2/3w_X=-2/3, which we introduce here to allow the evolution of the universal scale factor as a function of conformal time to exhibit a symmetry that relates the big bang to the future conformal singularity, such as in Penrose's conformal cyclic cosmology. Using recent cosmological observations, we constrain the present-day energy density of missing matter to be ΩX,0=−0.034±0.075\Omega_{X,0}=-0.034 \pm 0.075. This is consistent with the standard Λ\LambdaCDM model, but constraints on the energy densities of all the components are considerably broadened by the introduction of missing matter; significant relative probability exists even for ΩX,0∼0.1\Omega_{X,0} \sim 0.1, and so the presence of a missing matter component cannot be ruled out. As a result, a Bayesian model selection analysis only slightly disfavours its introduction by 1.1 log-units of evidence. Foregoing our symmetry requirement on the conformal time evolution of the universe, we extend our analysis by allowing wXw_X to be a free parameter. For this more generic `double dark energy' model, we find wX=−1.01±0.16w_X = -1.01 \pm 0.16 and ΩX,0=−0.10±0.56\Omega_{X,0} = -0.10 \pm 0.56, which is again consistent with the standard Λ\LambdaCDM model, although once more the posterior distributions are sufficiently broad that the existence of a second dark-energy component cannot be ruled out. The model including the second dark energy component also has an equivalent Bayesian evidence to Λ\LambdaCDM, within the estimation error, and is indistinguishable according to the Jeffreys guideline.Comment: Revised version emphasising a different version of the underlying symmetry, as published in JCA

    Tidal Dwarf Galaxies at Intermediate Redshifts

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    We present the first attempt at measuring the production rate of tidal dwarf galaxies (TDGs) and estimating their contribution to the overall dwarf population. Using HST/ACS deep imaging data from GOODS and GEMS surveys in conjunction with photometric redshifts from COMBO-17 survey, we performed a morphological analysis for a sample of merging/interacting galaxies in the Extended Chandra Deep Field South and identified tidal dwarf candidates in the rest-frame optical bands. We estimated a production rate about 1.4 {\times} 10^{-5} per Gyr per comoving volume for long-lived TDGs with stellar mass 3 {\times} 10^{8-9} solar mass at 0.5<z<1.1. Together with galaxy merger rates and TDG survival rate from the literature, our results suggest that only a marginal fraction (less than 10%) of dwarf galaxies in the local universe could be tidally-originated. TDGs in our sample are on average bluer than their host galaxies in the optical. Stellar population modelling of optical to near-infrared spectral energy distributions (SEDs) for two TDGs favors a burst component with age 400/200 Myr and stellar mass 40%/26% of the total, indicating that a young stellar population newly formed in TDGs. This is consistent with the episodic star formation histories found for nearby TDGs.Comment: 9 pages, 5 figures, Accepted for publication in Astrophysics & Space Scienc

    Use of Nonantiretroviral Medications That May Impact Neurocognition: Patterns and Predictors in a Large, Long-Term HIV Cohort Study

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    Background: Neurocognitive impairment is a frequent and often disabling comorbidity of HIV infection. In addition to antiretroviral therapies, individuals with HIV infection may commonly use nonantiretroviral medications that are known to cause neurocognitive adverse effects (NC-AE). The contribution of NC-AE to neurocognitive impairment is rarely considered in the context of HIV and could explain part of the variability in neurocognitive performance among individuals with HIV. Setting: Women’s Interagency HIV Study, a prospective, multisite, observational study of US women with and without HIV. Methods: After a literature review, 79 medications (excluding statins) with NC-AE were identified and reported by Women’s Interagency HIV Study participants. We examined factors associated with self-reported use of these medications over a 10-year period. Generalized estimating equations for binary outcomes were used to assess sociodemographic, behavioral, and clinical characteristics associated with NC-AE medication use. Results: Three thousand three hundred women (71% with HIV) and data from ~42,000 visits were studied. HIV infection was associated with NC-AE medication use (odds ratio = 1.52; 95% confidence interval: 1.35 to 1.71). After adjustment for HIV infection status, other predictors of NC-AE medication use included having health insurance, elevated depressive symptoms, prior clinical AIDS, noninjection recreational drug use, and an annual household income of <$12,000 (Ps < 0.004). NC-AE medication use was less likely among women who drank 1–7 or 8–12 alcoholic drinks/week (vs. abstaining) (P < 0.04). Conclusions: HIV infection was associated with NC-AE medication use, which may influence determinations of HIV-associated neurocognitive impairment. Providers should consider the impact of NC-AE medications when evaluating patients with HIV and concurrent neurocognitive symptoms

    Degree of Polypharmacy and Cognitive Function in Older Women with HIV

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    The number of people with HIV (PWH) experiencing age-associated comorbidities including those treated with medications and cognitive impairment is increasing. We examined associations between polypharmacy and cognition in older women with HIV (WWH) given their vulnerability to this comorbidity. Cross-sectional analysis capitalizing on Women's Interagency HIV Study data collected between 2014 and 2017. WWH meeting the following criteria were analyzed: age ≥50 years; availability of self-reported non-antiretroviral therapy (ART) medications data; and neuropsychological data. The number of non-ART medications used regularly in the prior 6 months was summed. Polypharmacy was categorized as none/low (0-4), moderate (5-9), or severe (≥10). Multivariable linear regression analyses examined polypharmacy-cognition (T-score) associations in the total sample and among virally suppressed (VS; < 20 copies/mL)-WWH after covariate adjustment for enrollment site, income, depressive symptoms, substance use (smoking, heavy alcohol, marijuana, crack, cocaine, and/or heroin), the Veterans Aging Cohort Study index (indicators of HIV disease and organ system function, hepatitis C virus serostatus), ART use, nadir CD4 count, and specific ART drugs (efavirenz, integrase inhibitors). We included 637 women (median age = 55 years; 72% Black). Ninety-four percent reported ART use in the past 6 months and 75% had HIV RNA <20 copies/mL. Comorbidity prevalence was high (61% hypertension; 26% diabetes). Moderate and severe polypharmacy in WWH were 34% and 24%. In WWH, severe polypharmacy was associated with poorer executive function (p = .007) and processing speed (p = .01). The same pattern of findings remained among VS-WWH. Moderate polypharmacy was not associated with cognition. Moderate and severe polypharmacy were common and associated with poorer executive function and processing speed in WWH. Severe polypharmacy may be a major contributor to the persistence of domain-specific cognitive complications in older WWH above and beyond the conditions that these medications are used to treat

    Time-integrated luminosity recorded by the BABAR detector at the PEP-II e+e- collider

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    This article is the Preprint version of the final published artcile which can be accessed at the link below.We describe a measurement of the time-integrated luminosity of the data collected by the BABAR experiment at the PEP-II asymmetric-energy e+e- collider at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and in a continuum region below each resonance. We measure the time-integrated luminosity by counting e+e-→e+e- and (for the ϒ(4S) only) e+e-→μ+μ- candidate events, allowing additional photons in the final state. We use data-corrected simulation to determine the cross-sections and reconstruction efficiencies for these processes, as well as the major backgrounds. Due to the large cross-sections of e+e-→e+e- and e+e-→μ+μ-, the statistical uncertainties of the measurement are substantially smaller than the systematic uncertainties. The dominant systematic uncertainties are due to observed differences between data and simulation, as well as uncertainties on the cross-sections. For data collected on the ϒ(3S) and ϒ(2S) resonances, an additional uncertainty arises due to ϒ→e+e-X background. For data collected off the ϒ resonances, we estimate an additional uncertainty due to time dependent efficiency variations, which can affect the short off-resonance runs. The relative uncertainties on the luminosities of the on-resonance (off-resonance) samples are 0.43% (0.43%) for the ϒ(4S), 0.58% (0.72%) for the ϒ(3S), and 0.68% (0.88%) for the ϒ(2S).This work is supported by the US Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), the Commissariat à l’Energie Atomique and Institut National de Physique Nucléaire et de Physiquedes Particules (France), the Bundesministerium für Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (The Netherlands), the Research Council of Norway, the Ministry of Education and Science of the Russian Federation, Ministerio de Ciencia e Innovación (Spain), and the Science and Technology Facilities Council (United Kingdom). Individuals have received support from the Marie-Curie IEF program (European Union) and the A.P. Sloan Foundation (USA)
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