6,245 research outputs found

    Single-spin azimuthal asymmetries in electroproduction of neutral pions in semi-inclusive deep-inelastic scattering

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    A single-spin asymmetry in the azimuthal distribution of neutral pions relative to the lepton scattering plane has been measured for the first time in deep-inelastic scattering of positrons off longitudinally polarized protons. The analyzing power in the sinφ moment of the cross section is 0.019±0.007(stat)±0.003(syst). This result is compared to single-spin asymmetries for charged pion production measured in the same kinematic range. The π^0 asymmetry is of the same size as the π^+ asymmetry and shows a similar dependence on the relevant kinematic variables. The asymmetry is described by a phenomenological calculation based on a fragmentation function that represents sensitivity to the transverse polarization of the struck quark

    Measurement of the Beam-Spin Azimuthal Asymmetry Associated with Deeply-Virtual Compton Scattering

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    The beam-spin asymmetry in hard electroproduction of photons has been measured. The data have been accumulated by the HERMES experiment at DESY using the HERA 27.6 GeV longitudinally polarized positron beam and an unpolarized hydrogen-gas target. The asymmetry in the azimuthal distribution of the produced photons in the angle φ relative to the lepton scattering plane was determined with respect to the helicity state of the incoming positron beam. The beam-spin analyzing power in the sinφ moment was measured to be -0.23±0.04(stat)±0.03(syst) in the missing-mass range below 1.7 GeV. The observed asymmetry is attributed to the interference of the Bethe-Heitler and deeply virtual Compton scattering processes

    Response maxima in time-modulated turbulence: Direct Numerical Simulations

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    The response of turbulent flow to time-modulated forcing is studied by direct numerical simulations of the Navier-Stokes equations. The large-scale forcing is modulated via periodic energy input variations at frequency ω\omega. The response is maximal for frequencies in the range of the inverse of the large eddy turnover time, confirming the mean-field predictions of von der Heydt, Grossmann and Lohse (Phys. Rev. E 67, 046308 (2003)). In accordance with the theory the response maximum shows only a small dependence on the Reynolds number and is also quite insensitive to the particular flow-quantity that is monitored, e.g., kinetic energy, dissipation-rate, or Taylor-Reynolds number. At sufficiently high frequencies the amplitude of the kinetic energy response decreases as 1/ω1/\omega. For frequencies beyond the range of maximal response, a significant change in phase-shift relative to the time-modulated forcing is observed.Comment: submitted to Europhysics Letters (EPL), 8 pages, 8 Postscript figures, uses epl.cl

    High Sensitivity Search for v_e’s from the Sun and Other Sources at KamLAND

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    Data corresponding to a KamLAND detector exposure of 0.28 kton yr has been used to search for ν̅ _e’s in the energy range 8.3 < E_(ν̅e) < 14.8  MeV. No candidates were found for an expected background of 1.1±0.4 events. This result can be used to obtain a limit on ν̅_e fluxes of any origin. Assuming that all ν̅_e flux has its origin in the Sun and has the characteristic ^8B solar ν_e energy spectrum, we obtain an upper limit of 3.7×10^2  cm^(-2) ^(s-1) (90% C.L.) on the ν̅_e flux. We interpret this limit, corresponding to 2.8×10^(-4) of the standard solar model ^8B ν_e flux, in the framework of spin-flavor precession and neutrino decay models

    Renalase, a catecholamine-metabolising enzyme?

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    Recently, a new FAD-dependent amine oxidase, renalase, was described. It was secreted by the kidney into the blood and shown to have significant cardiovascular actions, which were attributed to its catecholamine-metabolising activity. The authors concluded that renalase might be an important regulatory factor in human (patho)physiology. The catecholamine-metabolising activity of renalase in plasma contrasts with previous investigations where catecholamines were found to be stable in human plasma, provided autoxidation is prevented by an antioxidant. The claim of catecholamine-metabolising activity of renalase was based on the generation of H2O2 during incubation of the enzyme with catecholamines. Careful inspection and calculations of the data lead to the conclusion that the rate of H2O2 generation is far too low to be ascribed to enzymatic conversion of catecholamines by renalase. Renalase may well have important cardiovascular functions, but there is no proof that its actions are mediated through catecholamine-metabolising activity

    Response to “Does amantadine have a protective effect against COVID-19?”

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    What can Parkinson’s disease teach us about COVID-19?

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    ExplorEnz: the primary source of the IUBMB enzyme list

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    ExplorEnz is the MySQL database that is used for the curation and dissemination of the International Union of Biochemistry and Molecular Biology (IUBMB) Enzyme Nomenclature. A simple web-based query interface is provided, along with an advanced search engine for more complex Boolean queries. The WWW front-end is accessible at http://www.enzyme-database.org, from where downloads of the database as SQL and XML are also available. An associated form-based curatorial application has been developed to facilitate the curation of enzyme data as well as the internal and public review processes that occur before an enzyme entry is made official. Suggestions for new enzyme entries, or modifications to existing ones, can be made using the forms provided at http://www.enzyme-database.org/forms.php

    Rectifying Public Morals in Interwar Japan

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    This study of growing restrictions on cafés in Japan during the 1920s and 1930s provides a case study of moral regulation as a form of politics defined in a broad sense. Governmental authorities cracked down on cafés which they perceived to be the source of threats to established social norms and gender roles posed by « modem », Western trends of the 1920s. The repression demonstrates that Japan's prewar crisis was as much domestic and social as it was international and political. The Japanese police had played a social role in moral regulation since the Meiji period (1868-1912), but this was further expanded in the conflict over modernity.Cette étude porte sur les restrictions croissantes imposées aux cafés dans le Japon des années 1920 et 1930. Elle présente un cas de police des mœurs comme un aspect de la politique, au sens large du terme. Les autorités gouvernementales réprimèrent les cafés parce qu'elles voyaient l'origine des menaces que la vogue « moderne » inspirée de l'Occident faisait peser sur les normes sociales et les rôles sexuels établis. La répression montre que la crise japonaise d'avant-guerre était tout autant interne et sociale qu'internationale et politique. La police japonaise intervenait dans la régulation des mœurs depuis l'ère Meiji (1868-1912), mais le conflit relatif à la modernité donna une nouvelle expansion à ce rôle
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