784 research outputs found
sj-pdf-1-ahp-10.1177_08901171221088849 – Supplemental Material for Barriers and Facilitators to Lung Cancer Screening: A Physician Survey
No full textSupplemental Material, sj-pdf-1-ahp-10.1177_08901171221088849 for Barriers and Facilitators to Lung Cancer Screening: A Physician Survey by Margaret Lowenstein, Leah Karliner, Jennifer Livaudais-Toman, Steven Gregorich, Ana I. Velazquez, Maya Vijayaraghavan, Judith M.E. Walsh and Celia P. Kaplan in American Journal of Health Promotion</p
Pentaquarks
No full textI discuss the recent experimental and theoretical developments following the discovery of the theta**+ pentaquark - an exotic uudds over bar baryon resonance observed in the K N channel by several experiments, and an exotic Xi*****- (ddssu over bar ) reported by NA49 at CERN. I focus on the theoretical interpretation of the data, both in terms of quark and chiral degrees of freedom, on the predictions for related exotic states, and on several unresolved questions raised by the experimental data, such why some experiments observe the pentaquarks and other do not, the apparently extremely narrow width of the theta**+ and the determination of its parity. I also describe the likely properties of the proposed heavy-quark pentaquarks - an anticharmed exotic baryon theta//c (uuddc over bar ) and theta //b**+, (uuddb over bar ), which are expected to be extremely narrow or even stable against strong decays. H1 recently reported observation of a possible theta//c candidate in D*****- p channel. Pentaquarks are also being searched for in e**+e**- annihilation and gammagamma collisions in the LEP data and at B- factories
Doubly Heavy Tetraquarks and Baryons
No full textDuring the last three years strong experimental evidence from B and charm factories has been accumulating for the existence of exotic hadronic quarkonia, narrow resonances which cannot be made from a quark and an antiquark. Their masses and decay modes show that they contain a heavy quark-antiquark pair, but their quantum numbers are such that they must also contain a light quark-antiquark pair. The theoretical challenge has been to determine the nature of these resonances. The main possibilities are that they are either "genuine tetraquarks", i.e. two quarks and two antiquarks within one confinement volume, or "hadronic molecules" of two heavy-light mesons. In the last few months there as been more and more evidence in favor of the latter. I discuss the experimental data and its interpretation and provide fairly precise predictions for masses and quantum numbers of the additional exotic states which are naturally expected in the molecular picture but have yet to be observed. In addition, I provide arguments in favor of the existence of an even more exotic state – a hypothetical deuteron-like bound state of two heavy baryons. I also consider “baryon-like" states QQ' q¯q¯′, which if found will be direct evidence not just for near-threshold binding of two heavy mesons, but for genuine tetraquarks with novel color networks. I stress the importance of experimental search for doubly-heavy baryons in this context
Heavy exotic quarkonia and doubly heavy baryons
No full textDuring the last three years strong experimental evidence from B and charm factories has been accumulating for the existence of exotic hadronic quarkonia, narrow resonances which cannot be made from a quark and an antiquark. Their masses and decay modes show that they contain a heavy quark-antiquark pair, but their quantum numbers are such that they must also contain a light quark-antiquark pair. The main theoretical challenge has been to determine the nature of these resonances. The main possibilities are that they are either “genuine tetraquarks”, i.e. two quarks and two antiquarks within one confinement volume, or “hadronic molecules” of two heavy-light mesons. In the last few months there is more and more evidence in favor of the latter. In addition, there exist narrow resonances such as X(3872) which are not exotic but are closely related to the exotic states. Most likely such states are a mixture of hadronic molecules and excited quarkonia. I discuss the experimental data and its interpretation and provide fairly precise predictions for masses and quantum numbers of the additional exotic states which are naturally expected in the molecular picture but have yet to be observed. In addition, I provide arguments in favor of the existence of an even more exotic state – a hypothetical deuteron-like bound state of two heavy baryons. I also consider “baryon-like” states QQ′q̄q̄′, which if found will be direct evidence not just for near-threshold binding of two heavy mesons, but for genuine tetraquarks with novel color networks. I also stress the importance of experimental search for doubly-heavy baryons which are intimately connected with doubly heavy exotics
Pentaquarks and doubly heavy exotic mesons
No full textI discuss the experimental evidence for and theoretical interpretation of the new mesons and baryons with two heavy quarks. These include doubly-heavy baryons, exotic hadronic quarkonia and most recently a manifestly exotic pentaquark-like doubly heavy baryon with a minimal quark content uudc̄ discovered by LHCb, whose mass, decay mode and width are in agreement with a prediction based on a physical picture of a deuteron-like Σc D̄* “hadronic molecule”
A novel strong competitive inhibitor of complex I
No full textAbstractAlkaline incubation of NADH results in the formation of a very potent inhibitor of complex I (NADH:ubiquinone oxidoreductase). Mass spectroscopy (molecular mass equal to 696) and absorption spectroscopy suggest that the inhibitor is derived from attachment of two oxygen atoms to the nicotinamide moiety of NADH. The inhibitor is competitive with respect to NADH with a Ki of about 10−8M. The inhibitor efficiently suppresses NADH-oxidase, NADH-artificial acceptor reductase, and NADH-quinone reductase reactions catalyzed by submitochondrial particles, as well as the reactions catalyzed by either isolated complex I or the three subunit flavoprotein fragment of complex I
The Rule in the Light of Two-Dimensional QCD
No full textWe calculate in QCD the ratios of baryonic matrix elements of and four-fermion operators, with a view to understanding better the mechanism of enhancement in QCD. We find relatively small suppressions of both the scalar-scalar and vector-vector these results, in view of a suggestion that gluon condensation may be an important contributing factor in the enhancement seen in QCD. At the technical level, our calculation of the vector-vector operator matrix element requires a treatment of the time dependence of the QCD soliton which had not been developed in previous phenomenological calculations within this model.We calculate in QCD the ratios of baryonic matrix elements of and four-fermion operators, with a view to understanding better the mechanism of enhancement in QCD. We find relatively small suppressions of both the scalar-scalar and vector-vector four-fermion operators. We discuss the possible implications of these results, in view of a suggestion that gluon condensation may be an important contributing factor in the enhancement seen in QCD. At the technical level, our calculation of the vector-vector operator matrix element requires a treatment of the time dependence of the QCD soliton which had not been developed in previous phenomenological calculations within this model
Pentaquarks: Status Report
No full textI discuss the recent experimental and theoretical developments following the discovery of the Theta/sup positive pentaquark, an exotic uuddsmacron baryon resonance observed in the KN channel by several experiments, and an exotic Xi*/sup -$/(ddssumacron) reported by NA49 at CERN. I focus on the theoretical interpretation of the data, both in terms of quark and chiral degrees of freedom, on the predictions for related exotic states, and on several unresolved questions raised by the experimental data, such as why some experiments observe the pentaquarks and other don't, the apparently extremely narrow width of the Theta/sup positive and the determination of its parity. I also describe the likely properties of the proposed heavy-quark pentaquarks, an anticharmed exotic baryon Theta/sub c/ (uuddcmacron) and Theta/sub b//sup positive (uuddbmacron), which are expected to be extremely narrow or even stable against strong decays. H1 recently reported observation of a possible Theta/sub c/ candidate in D*e/sup positive /sup negative annihilation and gammagamma collisions in the LEP data and at B- factories
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