894 research outputs found

    Observation of Scaling Violations in Scaled Momentum Distributions at HERA

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    Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of xx and Q2Q^2 using the ZEUS detector. The evolution of the scaled momentum, xpx_p, with Q2,Q^2, in the range 10 to 1280 GeV2GeV^2, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of Q2Q^2.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

    The AMS-02 Time of Flight System. Final Design

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    The AMS-02 detector is a superconducting magnetic spectrometer that will operate on the International Space Station. The time of flight (TOF) system of AMS-02 is composed by four scintillator planes with 8, 8, 10, 8 counters each, read at both ends by a total of 144 phototubes. This paper describes the new design, the expected performances, and shows preliminary results of the ion beam test carried on at CERN on October 2002.Comment: 4 pages, 6 EPS figures. Proc. of the 28th ICRC (2003

    The AMS-02 RICH Imager Prototype - In-Beam Tests with 20 GeV/c per Nucleon Ions -

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    A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2<Z<~45 in various beam conditions and using different radiators. The charge Z and velocity beta resolutions have been measured.Comment: 4 pages, contribution to the ICRC 200

    The Time of Flight System of the AMS-02 Space Experiment

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    The Time-of-Flight (TOF) system of the AMS detector gives the fast trigger to the read out electronics and measures velocity, direction and charge of the crossing particles. The new version of the detector (called AMS-02) will be installed on the International Space Station on March 2004. The fringing field of the AMS-02 superconducting magnet is 1.0÷2.51.0\div2.5 kG where the photomultiplers (PM) are installed. In order to be able to operate with this residual field, a new type of PM was chosen and the mechanical design was constrained by requiring to minimize the angle between the magnetic field vector and the PM axis. Due to strong field and to the curved light guides, the time resolution will be 150÷180150\div180 ps, while the new electronics will allow for a better charge measurement.Comment: 5 pages, 4 figures. Proc. of 7th Int. Conf. on Adv. Tech. and Part. Phys., 15-19 October 2001,Como (Italy

    The Central Temperature of the Sun can be Measured via the 7^7Be Solar Neutrino Line

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    A precise test of the theory of stellar evolution can be performed by measuring the difference in average energy between the neutrino line produced by 7Be{\rm ^7Be} electron capture in the solar interior and the corresponding neutrino line produced in a terrestrial laboratory. The high temperatures in the center of the sun broaden the line asymmetrically, FWHM = 1.6~keV, and cause an average energy shift of 1.3~keV. The width of the 7^7Be neutrino line should be taken into account in calculations of vacuum neutrino oscillations.Comment: RevTeX file, 9 pages. For hardcopy with figure, send to [email protected]. Institute for Advanced Study number AST 93/4

    Sonoluminescence in Neutron Stars

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    After a brief discussion of a possible relationship between the electroweak phase transition in highly compressed matter and gravitational collapse, we examine the speculative possibility that the electroweak phase transition might be contemporarily occurring in processes in neutron stars. We conjecture that adiabatic compression of neutron star matter due to focusing of the energy from a supernova bounce into a very small volume could result in extreme densities, and Fermi levels or temperature above O\cal{O} (100 GeV). We propose a qualitative scenario for sonoluminescence in neutron stars and discuss possible observable consequences.Comment: 10 pages, LATEX format (requires worldsci.sty style file

    Marked efficacy of Rituximab in multifocal motor neuropathy associated with chronic lymphocytic leukemia

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    The authors describe a patient who presented a multifocal motor neuropathy (MMN) associated with a high anti-ganglioside antibody (anti-GM1 and anti-GD1) titer at the clinical onset of a B-cell chronic lymphocytic leukemia (B-CLL). Immunomodulation (IVIg plus cyclosporine) resulted in a neurological improvement and reduced anti-ganglioside antibody titers, both of which remained stable for at least six years. After this period, the patient had a severe relapse of the neuropathy, which was independent of the clinical course of the B-CLL. Both IVIg and cyclophosphamide were ineffective, and the patient became tetraplegic within six months; in the meantime, the patient displayed an increased antiganglioside antibody titer. Treatment with rituximab (RTX), which is designed to selectively inhibit B cell function, resulted in a dramatic, prompt and long-lasting neurological improvement as well as a reduced anti-ganglioside antibody titer. Although there are no previous reports of MMN in patients with B-CLL, the efficacy of RTX in the treatment of MMN in this patient may be considered remarkable. The expansion of B-cell clones may be a prerequisite for RTX effectiveness in MMN, and in dysimmune neuropathies in general

    Design of a large dynamic range readout unit for the PSD detector of DAMPE

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    A large dynamic range is required by the Plastic Scintillator Detector (PSD) of DArk Matter Paricle Explorer (DAMPE), and a double-dynode readout has been developed. To verify this design, a prototype detector module has been constructed and tested with cosmic rays and heavy ion beams. The results match with the estimation and the readout unit could easily cover the required dynamic range

    Marked efficacy of rituximab in multifocal motor neuropathy associated with chronic lymphocytic leukemia

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    The authors describe a patient who presented a multifocal motor neuropathy (MMN) associated with a high anti-ganglioside antibody (anti-GM1 and anti-GD1) titer at the clinical onset of a B-cell chronic lymphocytic leukemia (B-CLL). Immunomodulation (IVIg plus cyclosporine) resulted in a neurological improvement and reduced anti-ganglioside antibody titers, both of which remained stable for at least six years. After this period, the patient had a severe relapse of the neuropathy, which was independent of the clinical course of the B-CLL. Both IVIg and cyclophosphamide were ineffective, and the patient became tetraplegic within six months; in the meantime, the patient displayed an increased antiganglioside antibody titer. Treatment with rituximab (RTX), which is designed to selectively inhibit B cell function, resulted in a dramatic, prompt and long-lasting neurological improvement as well as a reduced antiganglioside antibody titer. Although there are no previous reports of MMN in patients with B-CLL, the eficacy of RTX in the treatment of MMN in this patient may be considered remarkable. The expansion of B-cell clones may be a prerequisite for RTX effectiveness in MMN, and in dysimmune neuropathies in general
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