3,389 research outputs found

    Spectrally resolved observations of atmospheric emitted radiance in the H2O rotation band

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    This paper presents the project Earth Cooling by Water Vapor Radiation, an observational programme, which aims at developing a database of spectrally resolved far infrared observations, in atmospheric dry conditions, in order to validate radiative transfer models and test the quality of water vapor continuum and line parameters. The project provides the very first set of far-infrared spectral downwelling radiance measurements, in dry atmospheric conditions, which are complemented with Raman Lidar-derived temperature and water vapor profiles

    Search for spontaneous muon emission from lead nuclei

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    We describe a possible search for muonic radioactivity from lead nuclei using the base elements ("bricks" composed by lead and nuclear emulsion sheets) of the long-baseline OPERA neutrino experiment. We present the results of a Monte Carlo simulation concerning the expected event topologies and estimates of the background events. Using few bricks, we could reach a good sensitivity level.Comment: 12 pages, 4 figure

    Electron/pion separation with an Emulsion Cloud Chamber by using a Neural Network

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    We have studied the performance of a new algorithm for electron/pion separation in an Emulsion Cloud Chamber (ECC) made of lead and nuclear emulsion films. The software for separation consists of two parts: a shower reconstruction algorithm and a Neural Network that assigns to each reconstructed shower the probability to be an electron or a pion. The performance has been studied for the ECC of the OPERA experiment [1]. The e/πe/\pi separation algorithm has been optimized by using a detailed Monte Carlo simulation of the ECC and tested on real data taken at CERN (pion beams) and at DESY (electron beams). The algorithm allows to achieve a 90% electron identification efficiency with a pion misidentification smaller than 1% for energies higher than 2 GeV

    Uncovering the signaling pathway behind extracellular guanine-induced activation of NO System: New perspectives in memory-related disorders

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    Mounting evidence suggests that the guanine-based purines stand out as key player in cell metabolism and in several models of neurodegenerative disorders, such as Parkinson's and Alzheimer's diseases. Guanosine (GUO) and guanine (GUA) are extracellular signaling molecules derived from the breakdown of the correspondent nucleotide, GTP, and their intracellular and extracellular levels are regulated by the fine-tuned activity of two major enzymes, purine nucleoside phosphorylase (PNP) and guanine deaminase (GDA). Noteworthy, GUO and GUA, seem to play opposite roles in the modulation of cognitive functions, such as learning and memory. Indeed GUO, despite exerting neuroprotective, anti-apoptotic and neurotrophic effects, causes a decay of cognitive activities, whereas GUA administration in rats results in working memory improvement (prevented by L-NAME pre-treatment). This study was designed to investigate, in a model of SH-SY5Y neuroblastoma cell line, the signal transduction pathway activated by extracellular GUA. Altogether, our results showed that: (i) in addition to an enhanced phosphorylation of ASK1, p38 and JNK, likely linked to a non-massive and transient ROS production, the PKB/NO/sGC/cGMP/PKG/ERK cascade seems to be the main signaling pathway elicited by extracellular GUA; (ii) the activation of this pathway occurs in a pertussis-toxin sensitive manner, thus suggesting the involvement of a putative G protein coupled receptor; (iii) the GUA-induced NO production, strongly reduced by cell pre-treatment with L-NAME, is negatively modulated by the EPAC-cAMP-CaMKII pathway, which causes the over-expression of GDA that, in turn, reduces the levels of GUA. These molecular mechanisms activated by GUA may be useful to support our previous observation showing that GUA improves learning and memory functions through the stimulation of NO signaling pathway, and underscore the therapeutic potential of oral administration of guanine for treating memory-related disorders

    Prospect for Charge Current Neutrino Interactions Measurements at the CERN-PS

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    Tensions in several phenomenological models grew with experimental results on neutrino/antineutrino oscillations at Short-Baseline (SBL) and with the recent, carefully recomputed, antineutrino fluxes from nuclear reactors. At a refurbished SBL CERN-PS facility an experiment aimed to address the open issues has been proposed [1], based on the technology of imaging in ultra-pure cryogenic Liquid Argon (LAr). Motivated by this scenario a detailed study of the physics case was performed. We tackled specific physics models and we optimized the neutrino beam through a full simulation. Experimental aspects not fully covered by the LAr detection, i.e. the measurements of the lepton charge on event-by-event basis and their energy over a wide range, were also investigated. Indeed the muon leptons from Charged Current (CC) (anti-)neutrino interactions play an important role in disentangling different phenomenological scenarios provided their charge state is determined. Also, the study of muon appearance/disappearance can benefit of the large statistics of CC muon events from the primary neutrino beam. Results of our study are reported in detail in this proposal. We aim to design, construct and install two Spectrometers at "NEAR" and "FAR" sites of the SBL CERN-PS, compatible with the already proposed LAr detectors. Profiting of the large mass of the two Spectrometers their stand-alone performances have also been exploited.Comment: 70 pages, 38 figures. Proposal submitted to SPS-C, CER

    Proposal for taking data with the KLOE-2 detector at the DAΦ\PhiNE collider upgraded in energy

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    This document reviews the physics program of the KLOE-2 detector at DAΦ\PhiNE upgraded in energy and provides a simple solution to run the collider above the ϕ\phi-peak (up to 2, possibly 2.5 GeV). It is shown how a precise measurement of the multihadronic cross section in the energy region up to 2 (possibly 2.5) GeV would have a major impact on the tests of the Standard Model through a precise determination of the anomalous magnetic moment of the muon and the effective fine-structure constant at the MZM_Z scale. With a luminosity of about 103210^{32}cm2^{-2}s1^{-1}, DAΦ\PhiNE upgraded in energy can perform a scan in the region from 1 to 2.5 GeV in one year by collecting an integrated luminosity of 20 pb1^{-1} (corresponding to a few days of data taking) for single point, assuming an energy step of 25 MeV. A few years of data taking in this region would provide important tests of QCD and effective theories by γγ\gamma\gamma physics with open thresholds for pseudo-scalar (like the η\eta'), scalar (f0,f0f_0,f'_0, etc...) and axial-vector (a1a_1, etc...) mesons; vector-mesons spectroscopy and baryon form factors; tests of CVC and searches for exotics. In the final part of the document a technical solution for the energy upgrade of DAΦ\PhiNE is proposed.Comment: 19 pages, 8 figure

    Emulsion sheet doublets as interface trackers for the OPERA experiment

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    New methods for efficient and unambiguous interconnection between electronic counters and target units based on nuclear photographic emulsion films have been developed. The application to the OPERA experiment, that aims at detecting oscillations between mu neutrino and tau neutrino in the CNGS neutrino beam, is reported in this paper. In order to reduce background due to latent tracks collected before installation in the detector, on-site large-scale treatments of the emulsions ("refreshing") have been applied. Changeable Sheet (CSd) packages, each made of a doublet of emulsion films, have been designed, assembled and coupled to the OPERA target units ("ECC bricks"). A device has been built to print X-ray spots for accurate interconnection both within the CSd and between the CSd and the related ECC brick. Sample emulsion films have been extensively scanned with state-of-the-art automated optical microscopes. Efficient track-matching and powerful background rejection have been achieved in tests with electronically tagged penetrating muons. Further improvement of in-doublet film alignment was obtained by matching the pattern of low-energy electron tracks. The commissioning of the overall OPERA alignment procedure is in progress.Comment: 19 pages, 19 figure
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