661 research outputs found

    Five critical quality criteria for artificial intelligence-based prediction models

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    To raise the quality of clinical artificial intelligence (AI) prediction modelling studies in the cardiovascular health domain and thereby improve their impact and relevancy, the editors for digital health, innovation, and quality standards of the European Heart Journal propose five minimal quality criteria for AI-based prediction model development and validation studies: complete reporting, carefully defined intended use of the model, rigorous validation, large enough sample size, and openness of code and software

    The decay constants of pseudoscalar mesons in a relativistic quark model

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    The decay constants of pseudoscalar mesons are calculated in a relativistic quark model which assumes that mesons are made of a valence quark antiquark pair and of an effective vacuum like component. The results are given in terms of quark masses and of some free parameters entering the expression of the internal wave functions of the mesons. By using the pion and kaon decay constants Fπ+=130.7 MeV, FK+=159.8 MeVF_{\pi^+}=130.7~MeV,~F_{K^+}=159.8~MeV to fix the parameters of the model one gets 60 MeVFD+185 MeV, 95 MeVFDs230 MeV, 80 MeVFB+205 MeV60~MeV\leq F_{D^+}\leq 185~MeV,~95~MeV\leq F_{D_s}\leq230~MeV,~80~MeV\leq F_{B^+}\leq205~MeV for the light quark masses mu=5.1 MeV, md=9.3 MeV, ms=175 MeVm_u=5.1~MeV,~m_d=9.3~MeV,~m_s=175~MeV and the heavy quark masses in the range: 1. GeVmc1.6 GeV, 4.1 GeVmb4.5 GeV1.~GeV\leq m_c\leq1.6~GeV,~4.1~GeV\leq m_b\leq4.5~GeV. In the case of light neutral mesons one obtains with the same set of parameters Fπ0138 MeV, Fη 130 MeV,Fη 78 MeVF_{\pi^0}\approx 138~MeV,~F_\eta\approx~130~MeV,F_{\eta'} \approx~78~MeV. The values are in agreement with the experimental data and other theoretical results.Comment: 11 pages, LaTe

    Di-electron and two-photon widths in charmonium

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    The vector and pseudoscalar decay constants are calculated in the framework of the Field Correlator Method. Di-electron widths: Γee(J/ψ)=5.41\Gamma_{ee}(J/\psi)=5.41 keV, Γee(ψ(3686))=2.47\Gamma_{ee}(\psi'(3686))=2.47 keV, Γee(ψ(3770))=0.248\Gamma_{ee}(\psi''(3770))=0.248 keV, in good agreement with experiment, are obtained with the same coupling, αs=0.165\alpha_s=0.165, in QCD radiative corrections. We show that the larger αs=0.191±0.004\alpha_s=0.191\pm 0.004 is needed to reach agreement with experiment for Γγγ(ηc)=7.22\Gamma_{\gamma\gamma}(\eta_c)=7.22 keV, Γγγ(χ(3P0))=3.3\Gamma_{\gamma\gamma} (\chi(^3P_0))=3.3 keV, Γγγ(χ(3P2))=0.54\Gamma_{\gamma\gamma}(\chi(^3P_2))= 0.54 keV, and also for Γ(J/ψ3g)=59.5\Gamma(J/\psi\to 3g)=59.5 keV, Γ(J/ψγ2g)=5.7\Gamma(J/\psi\to \gamma 2g)=5.7 keV. Meanwhile even larger αs=0.238\alpha_s=0.238 gives rise to good description of Γ(ψ3g)=52.7\Gamma(\psi'\to 3g)=52.7 keV, Γ(ψγ2g)=3.5\Gamma(\psi'\to \gamma 2g)= 3.5 keV, and provides correct ratio of the branching fractions: B(J/ψlighthadrons)B(ψlighthadrons)=0.24.\frac{\mathcal{B}(J/\psi\to light hadrons)}{\mathcal{B}(\psi'\to light hadrons)}=0.24.Comment: 8 pages, no figure

    Leptonic widths of high excitations in heavy quarkonia

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    Agreement with the measured electronic widths of the ψ(4040)\psi(4040), ψ(4415)\psi(4415), and Υ(11019)\Upsilon (11019) resonances is shown to be reached if two effects are taken into account: a flattening of the confining potential at large distances and a total screening of the gluon-exchange interaction at r\ga 1.2 fm. The leptonic widths of the unobserved Υ(7S)\Upsilon(7S) and ψ(5S)\psi(5S) resonances: Γe+e(Υ(7S))=0.11\Gamma_{e^+e^-}(\Upsilon (7S))=0.11 keV and Γ(ψ(5S))0.54\Gamma(\psi(5S))\approx 0.54 keV are predicted.Comment: 11 pages revtex

    Effect of integrated care for sick listed patients with chronic low back pain: economic evaluation alongside a randomised controlled trial

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    Objective To evaluate the cost effectiveness, cost utility, and cost-benefit of an integrated care programme compared with usual care for sick listed patients with chronic low back pain

    Mesons with Beauty and Charm: Spectroscopy

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    Applying knowledge of the interaction between heavy quarks derived from the study of ccc\overline{c} and bbb\overline{b} bound states, we calculate the spectrum of cbc\overline{b} mesons. We compute transition rates for the electromagnetic and hadronic cascades that lead from excited states to the 1S0^1\text{S}_0 ground state, and briefly consider the prospects for experimental observation of the spectrum.Comment: 32 pages + 2 uuencoded PostScript figures Fermilab-Pub-94/032-

    Spin Effects in Two Quark System and Mixed States

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    Based on the numeric solution of a system of coupled channels for vector mesons (SS- and DD-waves mixing) and for tensor mesons (PP- and FF-waves mixing) mass spectrum and wave functions of a family of vector mesons qqˉq\bar{q} in triplet states are obtained. The calculations are performed using a well known Cornell potential with a mixed Lorentz-structure of the confinement term. The spin-dependent part of the potential is taken from the Breit-Fermi approach. The effect of singular terms of potential is considered in the framework of the perturbation theory and by a configuration interaction approach (CIA), modified for a system of coupled equations. It is shown that even a small contribution of the DD-wave to be very important at the calculation of certain characteristics of the meson states.Comment: 12 pages, LaTe

    Anti‐cN‐1A autoantibodies are absent in juvenile dermatomyositis

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    Objectives: To assess anti‐cytosolic 5′‐nucleotidase 1A (cN‐1A/NTC51A) autoantibodies in children with juvenile dermatomyositis (JDM) and healthy controls, using three different methods of antibody detection, as well as verification of the results in an independent cohort. / Methods: Anti‐cN‐1A reactivity was assessed in 34 Dutch JDM patients and 20 healthy juvenile controls by a commercially available full‐length cN‐1A ELISA, a synthetic peptide ELISA and by immunoblotting using a lysate from cN‐1A expressing HEK‐293 cells. Sera from JDM patients with active disease and in remission were analysed. An independent British cohort of 110 JDM patients and 43 healthy juvenile controls was assessed by an in‐house full‐length cN‐1A ELISA. / Results: Anti‐cN‐1A reactivity was not present in JDM patients’ sera or in healthy controls when tested with the commercially available full‐length cN‐1A ELISA or by immunoblotting, both in active disease and in remission. Also, in the British JDM cohort anti‐cN‐1A reactivity was not detected. Three Dutch JDM patients tested weakly positive for one of the three synthetic cN‐1A peptides measured by ELISA. / Conclusion: JDM patients and young healthy individuals do not show anti‐cN‐1A reactivity as assessed by different antibody detection techniques

    A Brief Etymology of the Collateral Circulation

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    It is well known that the protective capacity of the collateral circulation falls short in many individuals with ischemic disease of the heart, brain and lower extremities. In the past fifteen years, opportunities created by molecular and genetic tools, together with disappointing outcomes in many “angiogenic” trials, has led to a significant increase in the number of studies that focus on: 1) understanding the basic biology of the collateral circulation; 2) identifying the mechanisms that limit the collateral circulation’s capacity in many individuals; 3) devising methods to measure collateral extent, which has been found to vary widely among individuals; and 4) developing treatments to increase collateral blood flow in obstructive disease. Unfortunately, accompanying this increase in reports has been a proliferation of vague terms used to describe the disposition and behavior of this unique circulation, as well as the increasing miss-use of well-ensconced ones by new (and old) students of the collateral circulation. With this in mind, we provide a brief glossary of readily understandable terms to denote the formation, adaptive growth, and mal-adaptive rarefaction of the collateral circulation. We also propose terminology for several newly discovered processes that occur in the collateral circulation. Finally, we include terms used to describe vessels that are sometimes confused with collaterals, as well as terms describing processes active in the general arterial-venous circulation when ischemic conditions engage the collateral circulation. We hope this brief review will help unify the terminology used in collateral research

    A Spectator-Quark-Model for the Photoproduction of Kaons

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    A simple model for the photoproduction of kaons off protons with a lambda hyperon in the final state is presented. In a quark model, the interaction is modelled by the pair-creation of the (anti-) strange quarks in the final state which recombine with the three quarks of the proton to form the lambda and kaon. The calculated scattering cross sections for photon energies up to E_\gamma = 1.9 \; \mbox{GeV} are compared to experiment. The pair-creation process is found to have a significant contribution to the total cross section.Comment: 16 pages, LaTex, 10 figures included; packed with 'uufiles' utilit
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