283 research outputs found

    Peut-on retrouver son chemin ? Résoudre les errances dans les suites du Roman comique

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    Deux suites du Roman comique datant du XVIIe siècle sont étudiées, celle dite d’Offray et celle de Préchac, afin de déterminer comment elles répondent à l’inachèvement du texte de Scarron. On observe dans quelle mesure elles proposent une continuation qui achève ou une suite qui rejoue

    Status of a Supersymmetric Flavour Violating Solution to the Solar Neutrino Puzzle with Three Generations

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    We present a general study of a three neutrino flavour transition model based on the supersymmetric interactions which violate R-parity. These interactions induce flavour violating scattering reactions between solar matter and neutrinos. The model does not contain any vacuum mass or mixing angle for the first generation neutrino. Instead, the effective mixing in the first generation is induced via the new interactions. The model provides a natural interpretation of the atmospheric neutrino anomaly, and is consistent with reactor experiments. We determine all R-parity violating couplings which can contribute to the effective neutrino oscillations, and summarize the present laboratory bounds. Independent of the specific nature of the (supersymmetric) flavour violating model, the experimental data on the solar neutrino rates and the recoil electron energy spectrum are inconsistent with the theoretical predictions. The confidence level of the χ2\chi^2-analysis ranges between 104\sim 10^{-4} and 103\sim 10^{-3}. The incompatibility, is due to the new SNO results, and excludes the present model. We conclude that a non-vanishing vacuum mixing angle for the first generation neutrino is necessary in our model. We expect this also to apply to the solutions based on other flavour violating interactions having constraints of the same order of magnitude.Comment: 17 pages, Latex fil

    Impact of front line relative dose intensity for methotrexate and comorbidities in immunocompetent elderly patients with primary central nervous system lymphoma

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    Primary central nervous system lymphomas (PCNSL) are non-Hodgkin lymphomas strictly localized to the CNS, occurring mainly in elderly patients with comorbidities. Current treatment in fit patients relies on high-dose methotrexate and high-dose cytarabine. The aim of this study was to evaluate the efficacy and feasibility of this treatment in elderly patients and to assess potential prognostic factors associated with survival. We conducted a retrospective study in two centers between January 2008 and September 2015 including 35 elderly immunocompetent patients who received first-line treatment with high-dose methotrexate. With a median follow-up of 19.8 months (range: 1.7-73.4 months), median overall survival (OS) was 39.5 months (95% confidence interval (95% CI): 18.3-60.7) and median progression-free survival (PFS) was 25.8 months (95% CI: 5.2-46.4). In univariate analysis, administration of high-dose cytarabine and achieving a relative dose intensity for methotrexate > 75% were associated with increased OS (p = 0.006 and p = 0.003, respectively) and PFS (p = 0.003 and p = 0.04, respectively) whereas comorbidities, defined by a CIRS-G score ≥ 8, were associated with decreased OS and PFS (p = 0.02 and p = 0.04, respectively). A high MSKCC score was associated with decreased OS (p = 0.02). In multivariate analysis, administration of high-dose cytarabine was associated with increased OS and PFS (p = 0.02 and p = 0.007, respectively). Comorbidities and relative dose intensity for methotrexate are important for the prognosis of elderly patients with PCNSL. These results must be confirmed in prospective trials

    Measurements of high-energy neutron-induced fission of (nat)Pb and (209)Bi

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial License 3.0, which permits unrestricted use, distribution, and reproduction in any noncommercial medium, provided the original work is properly citedThe CERN Neutron Time-Of-Flight (n_TOF) facility is well suited to measure low cross sections as those of neutron-induced fission in subactinides. The cross section ratios of (nat)Pb and (209)Bi relative to (235)U and (238)U were measured using PPAC detectors and a fragment coincidence method that allows us to identify the fission events. The present experiment provides first results for neutron-induced fission up to 1 GeV. Good agreement is found with previous experimental data below 200 MeV. The comparison with proton-induced fission indicates that the limiting regime where neutron-induced and proton-induced fission reach equal cross sections is close to 1 GeV

    Resonance capture cross section of 207Pb

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    The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77(8)% to the solar abundance of 207Pb. This corresponds to an r-process component of 23(8)%, which is important for deriving the U/Th ages of metal poor halo stars.Comment: 7 pages, 3 figures, to be published in Phys. Rev.

    Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN - N-TOF

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    The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN - n-TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards

    Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA

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    Deep-inelastic positron-proton interactions at low values of Bjorken-x down to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons are studied with the H1 experiment at HERA. The inclusive cross section for pi^0 mesons produced at small angles with respect to the proton remnant (the forward region) is presented as a function of the transverse momentum and energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x. Measurements are also presented of the transverse energy flow in events containing a forward pi^0 meson. Hadronic final state calculations based on QCD models implementing different parton evolution schemes are confronted with the data.Comment: 27 pages, 8 figures and 3 table

    Measurement of Leading Proton and Neutron Production in Deep Inelastic Scattering at HERA

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    Deep--inelastic scattering events with a leading baryon have been detected by the H1 experiment at HERA using a forward proton spectrometer and a forward neutron calorimeter. Semi--inclusive cross sections have been measured in the kinematic region 2 <= Q^2 <= 50 GeV^2, 6.10^-5 <= x <= 6.10^-3 and baryon p_T <= MeV, for events with a final state proton with energy 580 <= E' <= 740 GeV, or a neutron with energy E' >= 160 GeV. The measurements are used to test production models and factorization hypotheses. A Regge model of leading baryon production which consists of pion, pomeron and secondary reggeon exchanges gives an acceptable description of both semi-inclusive cross sections in the region 0.7 <= E'/E_p <= 0.9, where E_p is the proton beam energy. The leading neutron data are used to estimate for the first time the structure function of the pion at small Bjorken--x.Comment: 30 pages, 9 figures, 2 tables, submitted to Eur. Phys.
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