628 research outputs found

    What is the evidence base of used aggregated antibiotic resistance percentages to change empirical antibiotic treatment? A scoping review

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    Contains fulltext : 251404.pdf (Publisher’s version ) (Open Access)OBJECTIVES: Antibiotic resistance requires continuous monitoring by experts to decide whether empirical antibiotic therapies (EATs) should be replaced by alternative antibiotics. The exact moment and criteria for this change are unclear and generally based on consensus between experts. This scoping review aims to identify from the literature the resistance thresholds used for a change in EAT and the criteria on which they are based. METHODS: Scoping review for which a comprehensive structured literature search was conducted. Rayyan, software for systematic reviews, was used for the screening of abstracts and titles. Data sources were Pubmed and a hand-search of reference lists and grey literature. Papers were eligible if they concerned any type of bacterial infectious disease and mentioned or defined antibiotic resistance thresholds for decision-making purposes for EAT. The inclusion and analysis of articles was done by two researchers; any conflicts were resolved through discussion or by consulting a third reviewer. RESULTS: We identified 3146 unique papers. Following title/abstract screening, 125 papers were comprehensively read, and 16 papers were included. The included papers gave thresholds for urinary tract infections, respiratory tract infections, meningitis, skin and soft tissue infections, gonorrhoea, and bone and joint infections. Six criteria were found that were commonly used to base the thresholds on. These were: disease severity, efficacy of treatment, adverse drug events, risk of Clostridioides difficile infection, costs, and increased resistance. The number of criteria used to define each threshold varied from one to six between papers. CONCLUSIONS: The thresholds used for EATs are few, commonly based on expert opinion estimates, and can therefore have broad ranges. Used criteria underlying reported thresholds are heterogenous and require standardization. Considering the rising trend in resistance, there is a clear need for rigid tools to determine thresholds in order to support guideline development with the best and timely evidence

    Global change and groundwater

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    Groundwater (contained in sediments and rocks) constitutes the planet’s predominant reserve of fresh water, commonly with storage times from decades to centuries and millennia. Groundwater resources thus provide an excellent ‘buffer’ against the effects of climate variability on surface-water supplies, because of the generally large and widely- distributed storage reserves of aquifer systems. But questions arise as to how naturally resilient are groundwater reserves themselves to global change, and whether we are doing enough to help conserve and protect them

    Significance of E-lesions in Hodgkin lymphoma and the creation of a new consensus definition:a report from SEARCH

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    The International Staging Evaluation and Response Criteria Harmonization for Childhood, Adolescent, and Young Adult Hodgkin Lymphoma (SEARCH for CAYAHL) seeks to provide an appropriate, universal differentiation between E-lesions and stage IV extranodal disease in Hodgkin lymphoma (HL). A literature search was performed through the PubMed and Google Scholar databases using the terms “Hodgkin disease,” and “extranodal,” “extralymphatic,” “E lesions,” “E stage,” or “E disease.” Publications were reviewed for the number of participants; median age and age range; diagnostic modalities used for staging; and the definition, incidence, and prognostic significance of E-lesions. Thirty-six articles describing 12 640 patients met the inclusion criteria. Most articles reported staging per the Ann Arbor (72%, 26/36) or Cotswolds modification of the Ann Arbor staging criteria (25%, 9/36), and articles rarely defined E-lesions or disambiguated “extranodal disease.” The overall incidence of E-lesions for patients with stage I-III HL was 11.5% (1330/11 602 unique patients). Available stage-specific incidence analysis of 3888 patients showed a similar incidence of E-lesions in stage II (21.2%) and stage III (21.9%), with E-lesions rarely seen with stage I disease (1.1%). E-lesions likely remain predictive, but we cannot unequivocally conclude that identifying E-lesions in HL imparts prognostic value in the modern era of the more selective use of targeted radiation therapy. A harmonized E-lesion definition was reached based on the available evidence and the consensus of the SEARCH working group. We recommend that this definition of E-lesion be applied in future clinical trials with explicit reporting to confirm the prognostic value of E-lesions.</p

    Flux noise in high-temperature superconductors

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    Spontaneously created vortex-antivortex pairs are the predominant source of flux noise in high-temperature superconductors. In principle, flux noise measurements allow to check theoretical predictions for both the distribution of vortex-pair sizes and for the vortex diffusivity. In this paper the flux-noise power spectrum is calculated for the highly anisotropic high-temperature superconductor Bi-2212, both for bulk crystals and for ultra-thin films. The spectrum is basically given by the Fourier transform of the temporal magnetic-field correlation function. We start from a Berezinskii-Kosterlitz-Thouless type theory and incorporate vortex diffusion, intra-pair vortex interaction, and annihilation of pairs by means of a Fokker-Planck equation to determine the noise spectrum below and above the superconducting transition temperature. We find white noise at low frequencies omega and a spectrum proportional to 1/omega^(3/2) at high frequencies. The cross-over frequency between these regimes strongly depends on temperature. The results are compared with earlier results of computer simulations.Comment: 9 pages, 4 PostScript figures, to be published in Phys. Rev.

    Dynamic Scaling and Two-Dimensional High-Tc Superconductors

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    There has been ongoing debate over the critical behavior of two-dimensional superconductors; in particular for high Tc superconductors. The conventional view is that a Kosterlitz-Thouless-Berezinskii transition occurs as long as finite size effects do not obscure the transition. However, there have been recent suggestions that a different transition actually occurs which incorporates aspects of both the dynamic scaling theory of Fisher, Fisher, and Huse and the Kosterlitz-Thouless-Berezinskii transition. Of general interest is that this modified transition apparently has a universal dynamic critical exponent. Some have countered that this apparent universal behavior is rooted in a newly proposed finite-size scaling theory; one that also incorporates scaling and conventional two-dimensional theory. To investigate these issues we study DC voltage versus current data of a 12 angstrom thick YBCO film. We find that the newly proposed scaling theories have intrinsic flexibility that is relevant to the analysis of the experiments. In particular, the data scale according to the modified transition for arbitrarily defined critical temperatures between 0 K and 19.5 K, and the temperature range of a successful scaling collapse is related directly to the sensitivity of the measurement. This implies that the apparent universal exponent is due to the intrinsic flexibility rather than some real physical property. To address this intrinsic flexibility, we propose a criterion which would give conclusive evidence for phase transitions in two-dimensional superconductors. We conclude by reviewing results to see if our criterion is satisfied.Comment: 14 page

    First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons

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    We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/gamma* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/gamma* branching ratio to hadrons to be (0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)egamma* production, this product is found to be (4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters

    Calsequestrin as a risk factor in Graves’ hyperthyroidism and Graves’ ophthalmopathy patients

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    Background: The pathogenesis of Graves’ ophthalmopathy (GO), Graves’ hyperthyroidism (GH) and the mechanisms for its link to thyroid autoimmunity are poorly understood. Our research focuses on the role of the skeletal muscle calcium binding protein calsequestrin (CASQ1) in thyroid. We measured the concentration of the CASQ1 protein correlating levels with parameters of the eye signs, CASQ1 antibody levels and CASQ1 gene polymorphism rs3838284. Methods: CASQ1 protein was measured by quantitative Western Blotting. The protein concentrations were expressed as pmol/mg total protein by reference to CASQ1 standards. Results: Western blot analysis showed the presence of two forms of CASQ1 in the thyroid. The mean concentration of CASQ1 protein was significantly reduced in patients with Graves’ disease, compared to thyroid from control subjects with multi-nodular goitre or thyroid cancer. Although in patients with GO it was lower than that, compared with patients with GH this difference was not significant. Reduced CASQ1 in Graves’ thyroid correlated with the homozygous genotype of the rs3838284 CASQ1 polymorphism. Conclusions: Decreased CASQ1 in the thyroid of patients with Graves’ disease compared to thyroid from control subjects is not explained but may reflect consumption of the protein during an autoimmune reaction against CASQ1 in the thyroid

    Search for Higgs Bosons in e+e- Collisions at 183 GeV

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    The data collected by the OPAL experiment at sqrts=183 GeV were used to search for Higgs bosons which are predicted by the Standard Model and various extensions, such as general models with two Higgs field doublets and the Minimal Supersymmetric Standard Model (MSSM). The data correspond to an integrated luminosity of approximately 54pb-1. None of the searches for neutral and charged Higgs bosons have revealed an excess of events beyond the expected background. This negative outcome, in combination with similar results from searches at lower energies, leads to new limits for the Higgs boson masses and other model parameters. In particular, the 95% confidence level lower limit for the mass of the Standard Model Higgs boson is 88.3 GeV. Charged Higgs bosons can be excluded for masses up to 59.5 GeV. In the MSSM, mh > 70.5 GeV and mA > 72.0 GeV are obtained for tan{beta}>1, no and maximal scalar top mixing and soft SUSY-breaking masses of 1 TeV. The range 0.8 < tanb < 1.9 is excluded for minimal scalar top mixing and m{top} < 175 GeV. More general scans of the MSSM parameter space are also considered.Comment: 49 pages. LaTeX, including 33 eps figures, submitted to European Physical Journal

    Measurement of the Strong Coupling alpha s from Four-Jet Observables in e+e- Annihilation

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    Data from e+e- annihilation into hadrons at centre-of-mass energies between 91 GeV and 209 GeV collected with the OPAL detector at LEP, are used to study the four-jet rate as a function of the Durham algorithm resolution parameter ycut. The four-jet rate is compared to next-to-leading order calculations that include the resummation of large logarithms. The strong coupling measured from the four-jet rate is alphas(Mz0)= 0.1182+-0.0003(stat.)+-0.0015(exp.)+-0.0011(had.)+-0.0012(scale)+-0.0013(mass) in agreement with the world average. Next-to-leading order fits to the D-parameter and thrust minor event-shape observables are also performed for the first time. We find consistent results, but with significantly larger theoretical uncertainties.Comment: 25 pages, 15 figures, Submitted to Euro. Phys. J.
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