1,116 research outputs found

    Heavy χQ2\chi_{Q_2} tensor mesons in QCD

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    The masses and decay constants of the ground state heavy χQ2(Q=b,c)\chi_{Q2}(Q=b,c) tensor mesons are calculated in the framework of the QCD sum rules approach. The obtained results on the masses are in good consistency with the experimental values. Our predictions on the decay constants can be verified in the future experiments.Comment: 7 Pages and one Tabl

    Sensitive Observations of Radio Recombination Lines in Orion and W51: The Data and Detection of Systematic Recombination Line Blueshifts Proportional to Impact Broadening

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    Sensitive spectral observations made in two frequency bands near 6.0 and 17.6 GHz are described for Orion and W51. Using frequency switching we were able to achieve a dynamic range in excess of 10,000 without fitting sinusoidal or polynomial baselines. This enabled us to detect lines as weak as TA 1mKinthesestrongcontinuumsources.Hydrogenrecombinationlineswith_{A} ~1mK in these strong continuum sources. Hydrogen recombination lines with \Delta n$ as high as 25 have been detected in Orion. In the Orion data, where the lines are stronger, we have also detected a systematic shift in the line center frequencies proportional to linewidth that cannot be explained by normal optical depth effects.Comment: 22 pages, 13 figures. Accepted for publication in Astrophysics and Space Scienc

    The Effect of Sources on the Inner Horizon of Black Holes

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    Single pulse of null dust and colliding null dusts both transform a regular horizon into a space-like singularity in the space of colliding waves. The local isometry between such space-times and black holes extrapolates these results to the realm of black holes. However, inclusion of particular scalar fields instead of null dusts creates null singularities rather than space-like ones on the inner horizons of black holes.Comment: Final version to appear in PR

    Maternal and child health after injuries: a two-year follow-up of a nationally representative sample

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    Objective: The objective of this study was to examine the association between childhood injury and health outcomes among survivors and their mothers using a national survey in the United States (US). Study design: This was a longitudinal analysis of a nationally representative sample. Methods: Secondary analysis of the 1997–2013 Medical Expenditure Panel Survey (MEPS) was performed. Children (aged 2–18 years) with or without injuries were followed up for two years. Injuries captured in the study were those associated with at least one hospitalization, emergency department visit, or office-based visit. Outcome measures were child and maternal general and mental health status. Multiple mixed-logistic regressions were used with suboptimal health defined as the response of poor or fair health versus good, very good, or excellent health. Results: Of the 63,422 children analyzed, 3251 (4.9%) were injured, representing 3.6 million US children. Injured children were more likely to be male, white, and older than those without injuries (P < 0.01). About a fifth of injured children suffered head injuries. Injuries were strongly associated with suboptimal general and mental health status in children (adjusted odds ratios [AORs], 1.35 and 1.36, respectively, P < 0.05). Mothers of children with injuries were also more likely to report suboptimal mental health (AOR, 1.30, P < 0.05). Conclusion: Injuries among children are associated with lasting adverse effects in general and mental health. To improve health outcomes of pediatric injuries, further follow-up care may be needed to ensure that they return to pre-injury health levels. These results highlight the importance of primary prevention and the long-term impact of injuries on the health of children and their mothers

    EPR-Bell Nonlocality, Lorentz Invariance, and Bohmian Quantum Theory

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    We discuss the problem of finding a Lorentz invariant extension of Bohmian mechanics. Due to the nonlocality of the theory there is (for systems of more than one particle) no obvious way to achieve such an extension. We present a model invariant under a certain limit of Lorentz transformations, a limit retaining the characteristic feature of relativity, the non-existence of absolute time resp. simultaneity. The analysis of this model exemplifies an important property of any Bohmian quantum theory: the quantum equilibrium distribution ρ=ψ2\rho = |\psi |^2 cannot simultaneously be realized in all Lorentz frames of reference.Comment: 24 pages, LaTex, 4 figure

    Patient reported outcome of adult perioperative anaesthesia in the United Kingdom: a cross-sectional observational study

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    Background. Understanding the patient perspective on healthcare is central to the evaluation of quality. This study measured selected patient-reported outcomes after anaesthesia in order to identify targets for research and quality improvement. Methods. This cross-sectional observational study in UK National Health Service hospitals, recruited adults undergoing non-obstetric surgery requiring anaesthesia care over a 48 h period. Within 24 h of surgery, patients completed the Bauer questionnaire (measuring postoperative discomfort and satisfaction with anaesthesia care), and a modified Brice questionnaire to elicit symptoms suggestive of accidental awareness during general anaesthesia (AAGA). Patient, procedural and pharmacological data were recorded to enable exploration of risk factors for these poor outcomes. Results. 257 hospitals in 171 NHS Trusts participated (97% of eligible organisations). Baseline characteristics were collected on 16,222 patients; 15,040 (93%) completed postoperative questionnaires. Anxiety was most frequently cited as the worst aspect of the perioperative experience. Thirty-five per cent of patients reported severe discomfort in at least one domain: thirst (18.5%; 95% CI 17.8-19.1), surgical pain (11.0%; 10.5-11.5) and drowsiness (10.1%; 9.6-10.5) were most common. Despite this, only 5% reported dissatisfaction with any aspect of anaesthesia-related care. Regional anaesthesia was associated with a reduced burden of side-effects. The incidence of reported AAGA was one in 800 general anaesthetics (0.12%) Conclusions. Anxiety and discomfort after surgery are common; despite this, satisfaction with anaesthesia care in the UK is high. The inconsistent relationship between patient-reported outcome, patient experience and patient satisfaction supports using all three of these domains to provide a comprehensive assessment of the quality of anaesthesia care

    Equilibration processes in the Warm-Hot Intergalactic Medium

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    The Warm-Hot Intergalactic Medium (WHIM) is thought to contribute about 40-50 % to the baryonic budget at the present evolution stage of the universe. The observed large scale structure is likely to be due to gravitational growth of density fluctuations in the post-inflation era. The evolving cosmic web is governed by non-linear gravitational growth of the initially weak density fluctuations in the dark energy dominated cosmology. Non-linear structure formation, accretion and merging processes, star forming and AGN activity produce gas shocks in the WHIM. Shock waves are converting a fraction of the gravitation power to thermal and non-thermal emission of baryonic/leptonic matter. They provide the most likely way to power the luminous matter in the WHIM. The plasma shocks in the WHIM are expected to be collisionless. Collisionless shocks produce a highly non-equilibrium state with anisotropic temperatures and a large differences in ion and electron temperatures. We discuss the ion and electron heating by the collisionless shocks and then review the plasma processes responsible for the Coulomb equilibration and collisional ionisation equilibrium of oxygen ions in the WHIM. MHD-turbulence produced by the strong collisionless shocks could provide a sizeable non-thermal contribution to the observed Doppler parameter of the UV line spectra of the WHIM.Comment: 13 pages, 4 figures, accepted for publication in Space Science Reviews, special issue "Clusters of galaxies: beyond the thermal view", Editor J.S. Kaastra, Chapter 8; work done by an international team at the International Space Science Institute (ISSI), Bern, organised by J.S. Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke

    BICCO-Net II. Final report to the Biological Impacts of Climate Change Observation Network (BICCO-Net) Steering Group

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    • BICCO-Net Phase II presents the most comprehensive single assessment of climate change impacts on UK biodiversity to date. • The results provide a valuable resource for the CCRA 2018, future LWEC report cards, the National Adaptation Programme and other policy-relevant initiatives linked to climate change impacts on biodiversity

    Scaling anomaly in cosmic string background

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    We show that the classical scale symmetry of a particle moving in cosmic string background is broken upon inequivalent quantization of the classical system, leading to anomaly. The consequence of this anomaly is the formation of single bound state in the coupling interval \gamma\in(-1,1). The inequivalent quantization is characterized by a 1-parameter family of self-adjoint extension parameter \omega. It has been conjectured that the formation of loosely bound state in cosmic string background may lead to the so called anomalous scattering cross section for the particles, which is usually seen in molecular physics.Comment: 4 pages,1 figur

    Impacts of climate change on national biodiversity population trends

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    Climate change has had well-documented impacts on the distribution and phenology of species across many taxa, but impacts on species’ abundance, which relates closely to extinction risk and ecosystem function, have not been assessed across taxa. In the most comprehensive multi-taxa comparison to date, we modelled variation in national population indices of 501 mammal, bird, aphid, butterfly and moth species as a function of annual variation in weather variables, which through time allowed us to identify a component of species’ population growth that can be associated with post-1970s climate trends. We found evidence that these climate trends have significantly affected population trends of 15.8% of species, including eight with extreme (> 30% decline per decade) negative trends consistent with detrimental impacts of climate change. The modelled effect of climate change could explain 48% of the significant across-species population decline in moths and 63% of the population increase in winged aphids. The other taxa did not have significant across-species population trends or consistent climate change responses. Population declines in species of conservation concern were linked to both climatic and non-climatic factors respectively accounting for 42 and 58% of the decline. Evident differential impacts of climate change between trophic levels may signal the potential for future ecosystem disruption. Climate change has therefore already driven large-scale population changes of some species, had significant impacts on the overall abundance of some key invertebrate groups and may already have altered biological communities and ecosystems in Great Britain
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