661 research outputs found
Five critical quality criteria for artificial intelligence-based prediction models
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
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 to fix the parameters of the
model one gets for the light quark masses
and the heavy quark masses in the
range: . In the case of
light neutral mesons one obtains with the same set of parameters
. 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
The vector and pseudoscalar decay constants are calculated in the framework
of the Field Correlator Method. Di-electron widths:
keV, keV,
keV, in good agreement with experiment, are obtained with the same coupling,
, in QCD radiative corrections. We show that the larger
is needed to reach agreement with experiment for
keV, keV, keV, and
also for keV,
keV. Meanwhile even larger gives rise to good description of
keV, keV, and
provides correct ratio of the branching fractions: Comment: 8 pages, no figure
Leptonic widths of high excitations in heavy quarkonia
Agreement with the measured electronic widths of the ,
, and 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 and
resonances: keV and
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
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
Applying knowledge of the interaction between heavy quarks derived from the
study of and bound states, we calculate the
spectrum of mesons. We compute transition rates for the
electromagnetic and hadronic cascades that lead from excited states to the
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
Based on the numeric solution of a system of coupled channels for vector
mesons (- and -waves mixing) and for tensor mesons (- and -waves
mixing) mass spectrum and wave functions of a family of vector mesons
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 -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
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.
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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.
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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
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
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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