2,459 research outputs found

    Interface-induced heavy-hole/light-hole splitting of acceptors in silicon

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    The energy spectrum of spin-orbit coupled states of individual sub-surface boron acceptor dopants in silicon have been investigated using scanning tunneling spectroscopy (STS) at cryogenic temperatures. The spatially resolved tunnel spectra show two resonances which we ascribe to the heavy- and light-hole Kramers doublets. This type of broken degeneracy has recently been argued to be advantageous for the lifetime of acceptor-based qubits [Phys. Rev. B 88 064308 (2013)]. The depth dependent energy splitting between the heavy- and light-hole Kramers doublets is consistent with tight binding calculations, and is in excess of 1 meV for all acceptors within the experimentally accessible depth range (< 2 nm from the surface). These results will aid the development of tunable acceptor-based qubits in silicon with long coherence times and the possibility for electrical manipulation

    Outpatient antibiotic prescription trends in the United States: A national cohort study

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    OBJECTIVETo characterize trends in outpatient antibiotic prescriptions in the United StatesDESIGNRetrospective ecological and temporal trend study evaluating outpatient antibiotic prescriptions from 2013 to 2015SETTINGNational administrative claims data from a pharmacy benefits manager PARTICIPANTS. Prescription pharmacy beneficiaries from Express Scripts Holding CompanyMEASUREMENTSAnnual and seasonal percent change in antibiotic prescriptionsRESULTSApproximately 98 million outpatient antibiotic prescriptions were filled by 39 million insurance beneficiaries during the 3-year study period. The most commonly prescribed antibiotics were azithromycin, amoxicillin, amoxicillin/clavulanate, ciprofloxacin, and cephalexin. No significant changes in individual or overall annual antibiotic prescribing rates were found during the study period. Significant seasonal variation was observed, with antibiotics being 42% more likely to be prescribed during February than September (peak-to-trough ratio [PTTR], 1.42; 95% confidence interval [CI], 1.39–1.61). Similar seasonal trends were found for azithromycin (PTTR, 2.46; 95% CI, 2.44–3.47), amoxicillin (PTTR, 1.52; 95% CI, 1.42–1.89), and amoxicillin/clavulanate (PTTR, 1.78; 95% CI, 1.68–2.29).CONCLUSIONSThis study demonstrates that annual national outpatient antibiotic prescribing practices remained unchanged during our study period. Furthermore, seasonal peaks in antibiotics generally used to treat viral upper respiratory tract infections remained unchanged during cold and influenza season. These results suggest that inappropriate prescribing of antibiotics remains widespread, despite the concurrent release of several guideline-based best practices intended to reduce inappropriate antibiotic consumption; however, further research linking national outpatient antibiotic prescriptions to associated medical conditions is needed to confirm these findings.Infect Control Hosp Epidemiol 2018;39:584–589</jats:sec

    Effective antibiotic conservation by emergency antimicrobial stewardship during a drug shortage

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    We present the first description of an antimicrobial stewardship program (ASP) used to successfully manage a multi-antimicrobial drug shortage. Without resorting to formulary restriction, meropenem utilization decreased by 69% and piperacillin-tazobactam by 73%. During the shortage period, hospital mortality decreased (P=.03), while hospital length of stay remained unchanged.Infect Control Hosp Epidemiol 2017;38:356–359</jats:p

    Key Factors in the Medical Examination Product Design and Development Using Human Cell Image Totems

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    The industry of cultural creativity has a significant influence on the overall economy of a country. The development and application of cultural and creative products in different fields are growing more diverse. In the field of medicine, cultural and creative products can deliver more than aesthetic functions. They can bring healing benefits for patients with different symptoms in different age groups. Creative product designs that combine medicine and cultural/artistic creativity can make medical products warmer and friendlier to users. Focusing on the creative design of medical examination products, this study aims to provide references for more creative and friendly design of medical examination products to help reduce the fear and anxiety of patients when using such products. In this study, micro images of human cells are converted into totems as design elements for the design and development of cultural and creative products. These image totems not only represent the lively cellular world inside human body but also add aesthetics to the product design and make the products look warmer and friendlier to users. The research methods of literature survey, expert interview survey, and analytic hierarchy process (AHP) to first find out the factors in the medical product design using image totems of human cell mutation and reproduction and then measure the relative weight of each factor. Hopefully, the findings of this study can provide references for the creative design and development of medical examination products and help to enhance the design effectiveness. &nbsp; &nbsp; Keywords: cultural creativity industry, medical examination, products with healing effects, expert interview, analytic hierarchy process (AHP

    Systematic errors in strong gravitational lensing reconstructions, a numerical simulation perspective

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    We present the analysis of a sample of twenty-four SLACS-like galaxy-galaxy strong gravitational lens systems with a background source and deflectors from the Illustris-1 simulation. We study the degeneracy between the complex mass distribution of the lenses, substructures, the surface brightness distribution of the sources, and the time delays. Using a novel inference framework based on Approximate Bayesian Computation, we find that for all the considered lens systems, an elliptical and cored power-law mass density distribution provides a good fit to the data. However, the presence of cores in the simulated lenses affects most reconstructions in the form of a Source Position Transformation. The latter leads to a systematic underestimation of the source sizes by 50 per cent on average, and a fractional error in H0H_{0} of around 25−19+3725_{-19}^{+37} per cent. The analysis of a control sample of twenty-four lens systems, for which we have perfect knowledge about the shape of the lensing potential, leads to a fractional error on H0H_{0} of 12−3+612_{-3}^{+6} per cent. We find no degeneracy between complexity in the lensing potential and the inferred amount of substructures. We recover an average total projected mass fraction in substructures of fsub<1.7−2.0×10−3f_{\rm sub}<1.7-2.0\times10^{-3} at the 68 per cent confidence level in agreement with zero and the fact that all substructures had been removed from the simulation. Our work highlights the need for higher-resolution simulations to quantify the lensing effect of more realistic galactic potentials better, and that additional observational constraint may be required to break existing degeneracies.Comment: Accepted by MNRA

    Flavor and Spin Contents of the Nucleon in the Quark Model with Chiral Symmetry

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    A simple calculation in the framework of the chiral quark theory of Manohar and Georgi yields results that can account for many of the ''failures'' of the naive quark model: significant strange quark content in the nucleon as indicated by the value of σπN,\sigma _{\pi N}, the u‾\overline{u}-d‾\overline{d} asymmetry in the nucleon as measured by the deviation from Gottfried sum rule and by the Drell-Yan process, as well as the various quark contributions to the nucleon spin as measured by the deep inelastic polarized lepton-nucleon scatterings.Comment: figure has been separated from tex file. No other changes. Preprint CMU-HEP94-3

    Piezoelectric control of the magnetic anisotropy via interface strain coupling in a composite multiferroic structure

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    We investigate theoretically the magnetic dynamics in a ferroelectric/ferromagnetic heterostructure coupled via strain-mediated magnetoelectric interaction. We predict an electric field-induced magnetic switching in the plane perpendicular to the magneto-crystalline easy axis, and trace this effect back to the piezoelectric control of the magnetoelastic coupling. We also investigate the magnetic remanence and the electric coercivity
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