938 research outputs found

    Rates for the reactions antiproton-proton --> pi phi and gamma phi

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    We study antiproton-proton annihilation at rest into πϕ\pi\phi and ÎłÏ•\gamma\phi. Rescattering by K∗‟K+K∗K‟\overline{K^*}K+K^*\overline{K} and ρ+ρ−\rho^{+}\rho^{-} for p‟p→πϕ\overline{p}p\rightarrow\pi\phi states is sizable, of order (0.90 to 2.6)×10−4(0.90\, {\rm to}\,2.6)\times 10^{-4} in the branching ratio, but smaller than experiment. For p‟pâ†’ÎłÏ•\overline{p}p\rightarrow\gamma\phi the rescattering contributions are negligible, but the ÎłÏ•\gamma\phi channel is well explained by a ρϕ\rho\phi intermediate state combined with vector meson dominance.Comment: 12 pages, plain latex, 2 postscript figures available upon request, PSI-PR-93-2

    Branching Ratio and CP Asymmetry of B_s \to K^*_0(1430)\pi Decays in the PQCD Approach

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    In the two-quark model supposition for K0∗(1430)K_0^{*}(1430), the branching ratios and the direct CP-violating asymmetries for decays Bˉs0→K0∗0(1430)π0,K0∗+(1430)π−\bar B_s^0\to K^{*0}_0(1430)\pi^0, K^{*+}_0(1430)\pi^- are studied by employing the perturbative QCD factorization approach. We find that although these two decays are both tree-dominated, the ratio of their penguin to tree contributions are very different: there is only a few percent for the decay Bˉs0→K0∗+(1430)π−\bar B_s^0\to K^{*+}_0(1430)\pi^-, while about 37% in scenario I, even 51% in scenario II for the decay Bˉs0→K0∗0(1430)π0\bar B_s^0\to K^{*0}_0(1430)\pi^0. It results that these two decays have very different values in the branching ratios and the direct CP asymmetries. The branching ratio of the decay Bˉs0→K0∗+(1430)π−\bar B_s^0\to K^{*+}_0(1430)\pi^- is at the order of 10−510^{-5}, and its direct CP asymmetry is about (20-30)%. While for the decay Bˉs0→K0∗0(1430)π0\bar B_s^0\to K^{*0}_0(1430)\pi^0, its direct CP-violating asymmetry is very large and about 90%, but it is difficult to measure it, because the branching ratio for this channel is small and only 10−710^{-7} order.Comment: 8pages, 2figure

    Multivariate Anisotropic Interpolation on the Torus

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    We investigate the error of periodic interpolation, when sampling a function on an arbitrary pattern on the torus. We generalize the periodic Strang-Fix conditions to an anisotropic setting and provide an upper bound for the error of interpolation. These conditions and the investigation of the error especially take different levels of smoothness along certain directions into account

    Systematic Theoretical Search for Dibaryons in a Relativistic Model

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    A relativistic quark potential model is used to do a systematic search for quasi-stable dibaryon states in the uu, dd, and ss three flavor world. Flavor symmetry breaking and channel coupling effects are included and an adiabatic method and fractional parentage expansion technique are used in the calculations. The relativistic model predicts dibaryon candidates completely consistent with the nonrelativistic model.Comment: 12 pages, latex, no figure

    A Dispersive Analysis on the f0(600)f_0(600) and f0(980)f_0(980) Resonances in ÎłÎłâ†’Ï€+π−,π0π0\gamma\gamma\to\pi^+\pi^-, \pi^0\pi^0 Processes

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    We estimate the di-photon coupling of f0(600)f_0(600), f0(980)f_0(980) and f2(1270)f_2(1270) resonances in a coupled channel dispersive approach. The f0(600)f_0(600) di-photon coupling is also reinvestigated using a single channel TT matrix for ππ\pi\pi scattering with better analyticity property, and it is found to be significantly smaller than that of a qˉq\bar qq state. Especially we also estimate the di-photon coupling of the third sheet pole located near KˉK\bar KK threshold, denoted as f0III(980)f_0^{III}(980). It is argued that this third sheet pole may be originated from a coupled channel Breit-Wigner description of the f0(980)f_0(980) resonance.Comment: 24 pages and 13 eps figures. A nuerical bug in previous version is fixed. Some results changed. References and new figures added. Version to appear in Phys. Rev.

    An Inward-Facing Conformation of a Putative Metal-Chelate–Type ABC Transporter

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    The crystal structure of a putative metal-chelate–type adenosine triphosphate (ATP)–binding cassette (ABC) transporter encoded by genes HI1470 and HI1471 of Haemophilus influenzae has been solved at 2.4 angstrom resolution. The permeation pathway exhibits an inward-facing conformation, in contrast to the outward-facing state previously observed for the homologous vitamin B12 importer BtuCD. Although the structures of both HI1470/1 and BtuCD have been solved in nucleotide-free states, the pairs of ABC subunits in these two structures differ by a translational shift in the plane of the membrane that coincides with a repositioning of the membrane-spanning subunits. The differences observed between these ABC transporters involve relatively modest rearrangements and may serve as structural models for inward- and outward-facing conformations relevant to the alternating access mechanism of substrate translocation

    Occupations and geographical distribution of mesothelioma in Switzerland 1989-2018 - record linkage of an asbestos-exposed population with the Swiss National Cohort

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    OBJECTIVE We investigated the possibility of linking the data of the Swiss Laboratory for Particle Analysis (Silag), a valuable but incomplete data source in the field of asbestos-related diseases, to the Swiss National Cohort (SNC). With the resulting comprehensive dataset, we intended to provide a source for further research in the field. We also conducted preliminary analyses of data focusing on occupations and regional distribution of malignant pleural mesothelioma cases. METHODS Data of asbestos-exposed individuals available from the Silag were anonymously linked with the SNC by means of deterministic record linkage. From this linkage, data on occupation classified according to the international standard classification of occupations (ISCO) as well as the canton of residence in Switzerland could be retrieved. RESULTS Of 838 eligible individuals from the Silag data, 788 (94.0%) could be linked to the SNC database, including 476 mesothelioma cases. In 340 cases of the latter, data on occupation and industries were available. Although the majority of them were blue-collar workers, a significant proportion (n = 44, 12.9%) had executive professions. The Canton of residence in 1990 was established in 430 of subjects with mesothelioma. A cluster could be identified in eastern Switzerland, especially in the canton of Glarus. CONCLUSIONS It was possible to link the datasets to a large extent thereby creating a data source for further research. Of note, the linkage provided data on occupation of a selection of mesothelioma cases in Switzerland

    Spatial stochastic resonance in 1D Ising systems

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    The 1D Ising model is analytically studied in a spatially periodic and oscillatory external magnetic field using the transfer-matrix method. For low enough magnetic field intensities the correlation between the external magnetic field and the response in magnetization presents a maximum for a given temperature. The phenomenon can be interpreted as a resonance phenomenon induced by the stochastic heatbath. This novel "spatial stochastic resonance" has a different origin from the classical stochastic resonance phenomenon.Comment: REVTex, 5 pages, 3 figure

    Linguistic expert creation in online health practices

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    In this chapter, we explore how the construction of an expert identity varies across online e-health settings with different socio-technological features. Our methodology is qualitative in nature and draws on insights from discourse analysis, in particular positioning theory. Results show that four aspects of creating expertise are vital: the embeddedness of the posi-tioning strategies in the online health context, the interplay between these strategies within each setting, the interactivity of the medium, and the fact that not only professionals, but also clients and laypeople construct their expertise. The results reveal that previously found strategies to create expertise (e.g., using jargon or showing empathy) could be confirmed in our corpus, and that the interplay of several strategies is in fact needed to create credible and trustworthy expert identities for all participants involved. This interplay varies accord-ing to the practice

    Adaptation of the Stanford technique for treatment of bulky cutaneous T-cell lymphoma of the head

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