667 research outputs found

    VUV-Vis optical characterization of Tetraphenyl-butadiene films on glass and specular reflector substrates from room to liquid Argon temperature

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    The use of efficient wavelength-shifters from the vacuum-ultraviolet to the photosensor's range of sensitivity is a key feature in detectors for Dark Matter search and neutrino physics based on liquid argon scintillation detection. Thin film of Tetraphenyl-butadiene (TPB) deposited onto the surface delimiting the active volume of the detector and/or onto the photosensor optical window is the most common solution in current and planned experiments. Detector design and response can be evaluated and correctly simulated only when the properties of the optical system in use (TPB film + substrate) are fully understood. Characterization of the optical system requires specific, sometimes sophisticated optical methodologies. In this paper the main features of TPB coatings on different, commonly used substrates is reported, as a result of two independent campaigns of measurements at the specialized optical metrology labs of ENEA and University of Tor Vergata. Measured features include TPB emission spectra with lineshape and relative intensity variation recorded as a function of the film thickness and for the first time down to LAr temperature, as well as optical reflectance and transmittance spectra of the TPB coated substrates in the wavelength range of the TPB emission

    Efficacy of dupilumab in atopic comorbidities associated with moderate-to-severe adult atopic dermatitis

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    Background: Dupilumab is an anti-IL-4Rα antibody used in the treatment of patients with moderate-to-severe atopic dermatitis (msAD). This study explored the potential benefit of dupilumab in perennial allergic rhinoconjunctivitis (PAR) and perennial allergic asthma (PAA) caused by indoor allergens in adults with msAD. Methods: This multicentric, prospective, observational, real-life study included adult patients with msAD who had been treated with dupilumab in 16 Italian care centres. Efficacy outcomes regarding AD, PAR and PAA were collected at baseline and 16 weeks. Safety was also assessed. Results: We enrolled 123 patients with msAD. Between baseline and 16 weeks of treatment, the following measurements decreased statistically significantly: Eczema Area and Severity Index, SCOring AD, Patient-Oriented Eczema Measure, pruritus score, sleep score, Dermatology Life Quality Index and IgE. Dupilumab treatment in patients with comorbid PAR (n = 41) was associated with significant improvements in PAR disease control (measured using a Rhinitis Control Scoring System) and in PAR Quality of life (QoL) (measured using the Rhinoconjunctivitis QoL Questionnaire scores). In 32 patients with comorbid PAA, dupilumab significantly improved PAA control (measured using the Asthma Control Test and five-item Asthma Control Questionnaire scores) and disease-related QoL (measured using the Asthma QoL Questionnaire scores). Thirty-five patients (28.5%) developed conjunctivitis during the study period. Conclusion: These results support the benefits of dupilumab for adult patients with PAR and/or PAA associated with msAD

    π\piNN coupling and two-pion photoproduction on the nucleon

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    Effects of non-resonant photoproductions arising from two different πNN\pi NN couplings are investigated in the γN→ππN\gamma N\to\pi\pi N reaction. We find that the pseudoscalar (PS) πNN\pi NN coupling is generally preferable to the pseudovector (PV) πNN\pi NN coupling and particularly the total cross sections are successfully described by the model with the PS πNN\pi NN coupling. In order to see the difference between the two couplings, we also show the results of invariant mass spectra and helicity-dependent cross sections in various isospin channels calculated with the PS and PV couplings.Comment: 35 pages, 11 figures, minor changes and version to be published in Phys.Rev.

    Multiproxy investigation of the last 2,000 years BP marine paleoenvironmental record along the western Spitsbergen margin

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    A reconstruction of the last 2,000 years BP of environmental and oceanographic changes on the western margin of Spitsbergen was performed using a multidisciplinary approach including the fossil assemblages of diatoms, planktic and benthic foraminifera and calcareous nannofossils and the use of geochemistry (X-ray fluorescence spectroscopy, X-ray diffraction). We identified two warm periods (2,000–1,600 years BP and 1,300–700 years BP) that were associated with the Roman Warm Period and the Medieval Warm Period that alternate with colder oceanic conditions and sea ice coverage occurred during the Dark Ages (1,600–1,300 years BP) and the beginning of the Little Ice Age. During the Medieval Warm Period the occurrence of ice-rafted debris and Aulocoseira spp., a specific diatom genus commonly associated with continental freshwater, suggests significant runoff of meltwaters from local glaciers

    WARP: a WIMP double phase Argon detector

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    The WARP programme for dark matter search with a double phase argon detector is presented. In such a detector both excitation and ionization produced by an impinging particle are evaluated by the contemporary measurement of primary scintillation and secondary (proportional) light signal, this latter being produced by extracting and accelerating ionization electrons in the gas phase. The proposed technique, verified on a 2.3 liters prototype, could be used to efficiently discriminate nuclear recoils, induced by WIMP's interactions, and measure their energy spectrum. An overview of the 2.3 liters results and of the proposed 100 liters detector is shown.Comment: Proceeding for IDM200

    A search for the analogue to Cherenkov radiation by high energy neutrinos at superluminal speeds in ICARUS

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    The OPERA collaboration has claimed evidence of superluminal {\nu}{_\mu} propagation between CERN and the LNGS. Cohen and Glashow argued that such neutrinos should lose energy by producing photons and e+e- pairs, through Z0 mediated processes analogous to Cherenkov radiation. In terms of the parameter delta=(v^2_nu-v^2_c)/v^2_c, the OPERA result implies delta = 5 x 10^-5. For this value of \delta a very significant deformation of the neutrino energy spectrum and an abundant production of photons and e+e- pairs should be observed at LNGS. We present an analysis based on the 2010 and part of the 2011 data sets from the ICARUS experiment, located at Gran Sasso National Laboratory and using the same neutrino beam from CERN. We find that the rates and deposited energy distributions of neutrino events in ICARUS agree with the expectations for an unperturbed spectrum of the CERN neutrino beam. Our results therefore refute a superluminal interpretation of the OPERA result according to the Cohen and Glashow prediction for a weak current analog to Cherenkov radiation. In particular no superluminal Cherenkov like e+e- pair or gamma emission event has been directly observed inside the fiducial volume of the "bubble chamber like" ICARUS TPC-LAr detector, setting the much stricter limit of delta < 2.5 10^-8 at the 90% confidence level, comparable with the one due to the observations from the SN1987A.Comment: 17 pages, 6 figure

    Discovery of underground argon with low level of radioactive 39Ar and possible applications to WIMP dark matter detectors

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    We report on the first measurement of 39Ar in argon from underground natural gas reservoirs. The gas stored in the US National Helium Reserve was found to contain a low level of 39Ar. The ratio of 39Ar to stable argon was found to be <=4x10-17 (84% C.L.), less than 5% the value in atmospheric argon (39Ar/Ar=8x10-16). The total quantity of argon currently stored in the National Helium Reserve is estimated at 1000 tons. 39Ar represents one of the most important backgrounds in argon detectors for WIMP dark matter searches. The findings reported demonstrate the possibility of constructing large multi-ton argon detectors with low radioactivity suitable for WIMP dark matter searches.Comment: 6 pages, 2 figures, 2 table
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