8,984 research outputs found

    High-pressure/high-temperature synthesis of transition metal oxide perovskites

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    Perovskite and related Ruddlesden-Popper type transition metal oxides synthesised at high pressures and temperatures during the last decade are reviewed. More than 60 such new materials have been reported since 1995. Important developments have included perovskites with complex cation orderings on A and B sites, multiferroic bismuth-based perovskites, and new manganites showing colossal magnetoresistance (CMR) and charge ordering properties

    A Quantum Computing Algorithm for Smoothed Particle Hydrodynamics

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    This paper presents a quantum computing algorithm for the determination of function and gradient approximations in the Smoothed Particle Hydrodynamics (SPH) method. The SPH operators and domain discretisation are encoded in a quantum register using a careful normalisation procedure. The SPH summation is then performed via an inner product of quantum registers. This approach is tested in a classical sense for the kernel sum and first and second gradients of a function, using both the Gaussian and Wendland kernel functions, with comparisons for various register sizes made against analytical results. Error convergence is exponential in the number of qubits. It is hoped that this one-dimensional work will provide the foundation for a more general SPH algorithm, eventually leading to the highly efficient simulation of complex engineering problems on emerging quantum computers

    Impact of stout-link smearing in lattice fermion actions

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    The impact of stout-link smearing in lattice fermion actions is examined through the consideration of the mass and renormalization functions of the overlap quark propagator over a variety of smeared configurations. Up to six sweeps of stout-link smearing are investigated. For heavy quark masses, the quark propagator is strongly affected by the smearing procedure. For moderate masses, the effect appears to be negligible. A small effect is seen for light quark masses, where dynamical mass generation is suppressed through the smearing procedure.Comment: 7 pages, 3 figures, presented at the XXVII International Symposium on Lattice Field Theory - LAT2009, July 26-31 2009, Peking University, Beijing, Chin

    Stout-link smearing in lattice fermion actions

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    The properties of the momentum space quark propagator in Landau gauge are studied for the overlap quark action in quenched lattice QCD. Numerical calculations are performed over four ensembles of gauge configurations, where three are smeared using either 1, 3, or 6 sweeps of stout-link smearing. We calculate the non-perturbative wave function renormalization function Z(p)Z(p) and the non-perturbative mass function M(p)M(p) for a variety of bare quark masses. We find that the wave-function renormalization function is slightly sensitive to the number of stout-link smearing sweeps. For the mass function we find the effect of the stout-link smearing algorithm to be small for moderate to light bare quark masses. For a heavy bare quark mass we find a strong dependence on the number of smearing sweeps.Comment: 8 pages, 4 figure

    Low-lying Odd-parity States of the Nucleon in Lattice QCD

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    The world's first examination of the odd-parity nucleon spectrum at light quark masses in 2+1 flavor lattice QCD is presented. Configurations generated by the PACS-CS collaboration and made available through the ILDG are used, with the lightest pion mass at 156 MeV. A novel method for tracking the individual energy eigenstates as the quark mass changes is introduced. The success of this approach reveals the flow of the states towards the physical masses. Using the correlation matrix method, the two lowest-energy states revealed are found to be in accord with the physical spectrum of Nature.Comment: 5 page

    Roper Resonance in 2+1 Flavor QCD

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    The low-lying even-parity states of the nucleon are explored in lattice QCD using the PACS-CS collaboration 2+1-flavor dynamical-QCD gauge-field configurations made available through the International Lattice Datagrid (ILDG). The established correlation-matrix approach is used, in which various fermion source and sink smearings are utilized to provide an effective basis of interpolating fields to span the space of low-lying energy eigenstates. Of particular interest is the nature of the first excited state of the nucleon, the N1/2+N{1/2}^{+} Roper resonance of P11P_{11} pion-nucleon scattering. The Roper state of the present analysis approaches the physical mass, displaying significant chiral curvature at the lightest quark mass. These full QCD results, providing the world's first insight into the nucleon mass spectrum in the light-quark regime, are significantly different from those of quenched QCD and provide interesting insights into the dynamics of QCD.Comment: 7 pages, 5 figures. Revised version with new results to appear in PL

    A conceptual framework for secure mobile health

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    Mobile health is characterised by its diversity of applicability, in a multifaceted and multidisciplinary healthcare delivery continuum. In an environment of rapid change with the increasing development of mobile health, issues related to security and privacy must be well thought out. The different competing tensions in the development of mobile health from the device technologies and associated regulation, to clinical workflow and patient acceptance, require a framework for security that reflects the complex structure of this emerging field. There are three distinct associated elements that require investigation: technology, clinical, and human factors. Each of these elements consists of multiple aspects and there are specific risk factors to be addressed successively and co-dependently in each case. The fundamental approach to defining a conceptual framework for secure use of mobile health requires systematic identification of properties for the tensions and critical factors which impact these elements. The resulting conceptual framework presented here can be used for new critique, augmentation or deployment of mobile health solutions from the perspective of data protection and security

    Protocol for electrophysiological monitoring of carotid endarterectomies.

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    Near zero stroke rates can be achieved in carotid endarterectomy (CEA) surgery with selective shunting and electrophysiological neuromonitoring. though false negative rates as high as 40% have been reported. We sought to determine if improved training for interpretation of the monitoring signals can advance the efficacy of selective shunting with electrophysiological monitoring across multiple centers, and determine if other factors could contribute to the differences in reports. Processed and raw beta band (12.5-30 Hz) electroencephalogram (EEG) and median and tibial nerve somatosensory evoked potentials (SSEP) were monitored in 668 CEA cases at six surgical centers. A decrease in amplitude of 50% or more in any EEG or SSEP channel was the criteria for shunting or initiating a neuroprotective protocol. A reduction of 50% or greater in the beta band of the EEG or amplitude of the SSEP was observed in 150 cases. No patient showed signs of a cerebral infarct after surgery. Selective shunting based on EEG and SSEP monitoring can reduce CEA intraoperative stroke rate to a near zero level if trained personnel adopted standardized protocols. We also found that the rapid administration of a protective stroke protocol by attending anesthesiologists was an important aspect of this success rate

    Readability, presentation and quality of allergy-related patient information leaflets: a cross sectional and longitudinal study

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    Objective: Patient information leaflets (PILs) are widely used to reinforce or illustrate health information and to complement verbal consultation. The objectives of the study were to assess the readability and presentation of PILs published by Allergy UK, and to conduct a longitudinal assessment to evaluate the impact of leaflet amendment and revision on readability. Methods: Readability of Allergy UK leaflets available in 2013 was assessed using Simple Measure of Gobbledegook (SMOG) and Flesch-Kincaid Reading Grade Formula. Leaflet presentation was evaluated using the Clear Print Guidelines of the Royal National Institute of Blind People (RNIB) and the Patient Information Appraisal System developed by the British Medical Association (BMA). Changes in the leaflets’ readability scores over five years were investigated. Results: 108 leaflets, covering a wide range of allergic conditions and treatment options, were assessed. The leaflets had average SMOG and Flesch-Kincaid scores of 13.9 (range 11-18, SD 1.2) and 10.9 (range 5-17, SD 2.1) respectively. All leaflets met the RNIB Clear Print guidelines, with the exception of font size which was universally inadequate. The leaflets scored on average 10 (median 10, range 7-15) out of a maximum of 27 on the BMA checklist. The overall average SMOG score of 31 leaflets available in both 2008 and 2013 had not changed significantly. The process of leaflet revision resulted in 1% change in readability scores overall, with a predominantly upward trend with six leaflets increasing their readability score by >10% and only three decreasing by >10%. Conclusion: Allergy-related patient information leaflets are well presented but have readability levels that are higher than those recommended for health information. Involving service users in the process of leaflet design, together with systematic pre-publication screening of readability would enhance the accessibility and comprehensibility of written information for people with allergy and their careers