10,645 research outputs found

    MACRO results on atmospheric neutrinos

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    We discuss the final results of the MACRO experiment on atmospheric neutrino oscillations. The data concern event topologies with average neutrino energies of ~3 and ~50 GeV. Multiple Coulomb Scattering of the high energy muons was used to estimate the neutrino energy event by event. The angular distributions, the L/E_nu distribution, the particle ratios and the absolute fluxes all favor nu_mu --> nu_tau oscillations with maximal mixing and Delta m^2 ~0.0023 eV^2. Emphasis is given to measured ratios which are not affected by Monte Carlo (MC) absolute normalization; a discussion is made on MC uncertainties. A preliminary search for possible Lorentz invariance violation contributions to atmospheric neutrino oscillations is presented and discussed.Comment: 4 pages, 6 figures. Paper presented at the NOW 2004 Workshop, Conca Specchiulla, Otranto, Italy, September 200

    Neutrino physics and astrophysics with the MACRO detector

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    After a brief presentation of the MACRO detector we discuss the data on atmospheric neutrinos and neutrino oscillations, on high energy (E> 1 GeV) neutrino astronomy, on indirect searches for WIMPs and low energy (E >7 MeV) stellar collapse neutrinos.Comment: 8 pages, 7 figures. Invited paper at the Chacaltaya Meeting on Cosmic Ray Physics, La Paz, 23-27 July, 200

    Nuclear Track Detectors for Environmental Studies and Radiation Monitoring

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    Several improvements were made for Nuclear Track Detectors (NTDs) used for environmental studies and for particle searches. A new method was used to determine the bulk etch rate of CR39 and Makrofol NTDs. It is based on the simultaneous measurement of the diameter and of the height of etch-pit cones caused by relativistic heavy ions (158 A GeV Pb(82+) and In(49+) ions) and their fragments. The use of alcohol in the etching solution improves the surface quality of NTDs and it raises their thresholds. The detectors were used for the determination of nuclear fragmentation cross sections of Iron and Silicon ions of 1.0 and 0.41 GeV/nucleon. These measurements are important for the determination of doses in hadron therapy and for doses received by astronauts. The detectors were also used in the search of massive particles in the cosmic radiation, for the determination of the mass spectrum of cosmic rays and for the evaluation of Po(210) alpha decay and of natural radon concentrations.Comment: 7 pages, 5 EPS figures. Presented at the 10th Topical Seminar on Innovative Particle and Radiation Detectors, 1-5 October 2006, Siena, Ital

    New results on the limit for the width of the exotic Theta^+ resonance

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    We investigate the impact of the \Theta^+(1540) resonance on differential and integrated cross sections for the reaction K^+d{\to}K^0pp, where experimental information is available at kaon momenta below 640 MeV/c. The calculation utilizes the J\"ulich KN model and extensions of it that include contributions from a \Theta^+(1540) state with different widths. The evaluation of the reaction K^+d{\to}K^0pp takes into account effects due to the Fermi motion of the nucleons within the deuteron and the final three-body kinematics. We conclude that the available data constrain the width of the \Theta^+(1540) to be less than 1 MeV.Comment: 5 pages, 5 figures, updated version, accepted for publication in Phys. Lett.

    A higher Angiogenin expression is associated with a non-nuclear Maspin location in laryngeal carcinoma

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    Objectives. In numerous malignancies, angiogenin (ANG) and Maspin are important proangiogenic and antiangiogenic regulators, respectively. The aim of this study was to identify potential relationships between the biological roles of these two proteins in laryngeal squamous cell carcinoma (LSCC). Methods. Immunohistochemical staining for ANG and Maspin was performed on specimens from 76 consecutive LSCC patients treated with surgery alone, considering the subcellular pattern of Maspin expression. Univariate and multivariate statistical models were used for prognostic purposes. Results. On univariate analysis, a different level of ANG expression was seen for patients stratified by subcellular Maspin expression pattern: the mean ANG expression was higher in cases with a nonnuclear MASPIN expression than in those with a nuclear pattern (P=0.002). Disease-free survival (DFS; in months) differed significantly when patients were stratified by N stage (P=0.01). Patients whose Maspin expression was nonnuclear (i.e., it was cytoplasmic or there was none) had a significantly higher recurrence rate (P<0.001), and shorter DFS (P=0.01) than those with a nuclear Maspin pattern. The mean ANG expression was significantly higher in cases with loco-regional recurrent disease (P=0.007); and patients with an ANG expression 655.0% had a significantly shorter DFS than those with an ANG expression <5.0% (P=0.007). On multivariate analysis, ANG expression 655.0% was a significant, independent, negative prognostic factor in terms of DFS (P=0.041). Conclusion. Our results support the hypothesis that a higher ANG expression is associated with a nonnuclear Maspin expression pattern in patients with LSCC. Further studies are needed to clarify the relationship between the ANG and Maspin pathways, and their potential diagnostic and therapeutic role in LSCC
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