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Search Results: 1 - 10 of 219513 matches for " C. Nones "
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Tunable Superconducting Properties of a-NbSi Thin Films and Application to Detection in Astrophysics
O. Crauste,C. A. Marrache-Kikuchi,L. Berge,S. Collin,Y. Dolgorouky,S. Marnieros,C. Nones,L. Dumoulin
Physics , 2011, DOI: 10.1007/s10909-010-0284-2
Abstract: We report on the superconducting properties of amorphous NbxSi1-x thin films. The normal-state resistance and critical temperatures can be separately adjusted to suit the desired application. Notably, the relatively low electron-phonon coupling of these films makes them good candidates for an "all electron bolometer" for Cosmological Microwave Background radiation detection. Moreover, this device can be made to suit both high and low impedance readouts.
Rejection of randomly coinciding 2ν2β events in ZnMoO4 scintillating bolometers
D. M. Chernyak,F. A. Danevich,A. Giuliani,M. Mancuso,C. Nones,E. Olivieri,M. Tenconi,V. I. Tretyak
Physics , 2013, DOI: 10.1051/epjconf/20136504002
Abstract: Random coincidence of 2{\nu}2{\beta} decay events could be one of the main sources of background for 0{\nu}2{\beta} decay in cryogenic bolometers due to their poor time resolution. Pulse-shape discrimination by using front edge analysis, the mean-time and \c{hi}2 methods was applied to discriminate randomly coinciding 2{\nu}2{\beta} events in ZnMoO4 cryogenic scintillating bolometers. The background can be effectively rejected on the level of 99% by the mean-time analysis of heat signals with the rise time about 14 ms and the signal-to-noise ratio 900, and on the level of 98% for the light signals with 3 ms rise time and signal-to-noise ratio of 30 (under a requirement to detect 95% of single events). Importance of the signal-to-noise ratio, correct finding of the signal start and choice of an appropriate sampling frequency are discussed.
Rejection of randomly coinciding events in ZnMoO$_4$ scintillating bolometers
D. M. Chernyak,F. A. Danevich,A. Giuliani,M. Mancuso,C. Nones,E. Olivieri,M. Tenconi,V. I. Tretyak
Physics , 2014, DOI: 10.1140/epjc/s10052-014-2913-4
Abstract: Random coincidence of events (particularly from two neutrino double beta decay) could be one of the main sources of background in the search for neutrinoless double beta decay with cryogenic bolometers due to their poor time resolution. Pulse-shape discrimination by using front edge analysis, mean-time and $\chi^2$ methods was applied to discriminate randomly coinciding events in ZnMoO$_4$ cryogenic scintillating bolometers. These events can be effectively rejected at the level of 99% by the analysis of the heat signals with rise-time of about 14 ms and signal-to-noise ratio of 900, and at the level of 92% by the analysis of the light signals with rise-time of about 3 ms and signal-to-noise ratio of 30, under the requirement to detect 95% of single events. These rejection efficiencies are compatible with extremely low background levels in the region of interest of neutrinoless double beta decay of $^{100}$Mo for enriched ZnMoO$_4$ detectors, of the order of $10^{-4}$ counts/(y keV kg). Pulse-shape parameters have been chosen on the basis of the performance of a real massive ZnMoO$_4$ scintillating bolometer. Importance of the signal-to-noise ratio, correct finding of the signal start and choice of an appropriate sampling frequency are discussed.
Changes in colon gene expression associated with increased colon inflammation in interleukin-10 gene-deficient mice inoculated with Enterococcus species
Matthew PG Barnett, Warren C McNabb, Adrian L Cookson, Shuotun Zhu, Marcus Davy, Bianca Knoch, Katia Nones, Alison J Hodgkinson, Nicole C Roy
BMC Immunology , 2010, DOI: 10.1186/1471-2172-11-39
Abstract: At 12 weeks of age, total RNA extracted from intact colon was hybridized to Agilent 44 k mouse arrays. Differentially expressed genes were identified using linear models for microarray analysis (Bioconductor), and these genes were clustered using GeneSpring GX and Ingenuity Pathways Analysis software. Intestinal inflammation was increased in Il10-/- mice as a result of inoculation, with the strongest effect being in the EF and EF·CIF groups. Genes differentially expressed in Il10-/- mice as a result of EF or EF·CIF inoculation were associated with the following pathways: inflammatory disease (111 genes differentially expressed), immune response (209 genes), antigen presentation (11 genes, particularly major histocompatability complex Class II), fatty acid metabolism (30 genes) and detoxification (31 genes).Our results suggest that colonic inflammation in Il10-/- mice inoculated with solutions containing Enterococcus strains is associated with gene expression changes similar to those of human IBD, specifically CD, and that with the EF·CIF inoculum in particular this is an appropriate model to investigate food-gene interactions relevant to human CD.The term 'Inflammatory Bowel Disease' (IBD) refers to a heterogeneous collection of conditions characterized by chronic inflammation of the gastrointestinal tract, and includes Crohn's Disease (CD) and Ulcerative Colitis (UC) [1]. While there is some overlap in disease pathology, CD and UC also have distinct pathologic features; CD can, for example, affect any part of the gastrointestinal tract, whereas UC is confined to the colon and rectum, often causing diarrhea. The inflammation seen in CD is typically discontinuous, segmental and involves all layers of the intestinal wall. In UC, inflammation tends to be continuous and superficial, only affecting the mucosal layer of the colonic wall [2].The exact etiology and pathogenesis of IBD is still unclear, although there is strong epidemiological evidence for a genetic contribu
Background suppression in massive TeO$_2$ bolometers with Neganov-Luke amplified light detectors
N. Casali,L. Dumoulin,A. Giuliani,M. Mancuso,P. de Marcillac,S. Marnieros,S. S. Nagorny,C. Nones,E. Olivieri,L. Pagnanini,L. Pattavina,S. Pirro,D. Poda,C. Rusconi,K. Sch?effner,M. Tenconi
Physics , 2015,
Abstract: Bolometric detectors are excellent devices for the investigation of neutrinoless double-beta decay (0$\nu\beta\beta$). The observation of such decay would demonstrate the violation of lepton number, and at the same time it would necessarily imply that neutrinos have a Majorana character. The sensitivity of cryogenic detectors based on TeO$_2$ is strongly limited by the alpha background in the region of interest for the 0$\nu\beta\beta$ of $^{130}$Te. It has been demonstrated that particle discrimination in TeO$_2$ bolometers is possible measuring the Cherenkov light produced by particle interactions. However an event-by-event discrimination with NTD-based light detectors has to be demonstrated. We will discuss the performance of a highly-sensitive light detector exploiting the Neganov-Luke effect for signal amplification. The detector, being operated with NTD-thermistor and coupled to a 750 g TeO$_2$ crystal, shows the ability for an event-by-event identification of electron/gamma and alpha particles. The extremely low detector baseline noise, RMS 19 eV, demonstrates the possibility to enhance the sensitivity of TeO$_2$-based 0$\nu\beta\beta$ experiment to an unprecedented level.
Potential of a next generation neutrinoless double beta decay experiment based on ZnMoO4 scintillating bolometers
J. W. Beeman,F. A. Danevich,V. Ya. Degoda,E. N. Galashov,A. Giuliani,V. V. Kobychev,M. Mancuso,S. Marnieros,C. Nones,E. Olivieri,G. Pessina,C. Rusconi,V. N. Shlegel,V. I. Tretyak,Ya. V. Vasiliev
Physics , 2011, DOI: 10.1016/j.physletb.2012.03.009
Abstract: The search for neutrinoless double beta decay probes lepton number conservation with high sensitivity and investigates the neutrino nature and mass scale. Experiments presently in preparation will cover the quasi-degeneracy region of the neutrino mass pattern. Probing the so-called inverted hierarchy region requires improved sensitivities and next-generation experiments, based either on large expansions of the present searches or on new ideas. We examine here the potential of a novel technology relying on ZnMoO4 scintillating bolometers, which can provide an experiment with background close to zero in the ton x year exposure scale. The promising performance of a pilot detector is presented, both in terms of energy resolution and background control. A preliminary study of the sensitivities of future experiments shows that the inverted hierarchy region is within the reach of the technique here proposed. A realistic phased approach program towards a next-generation search is presented and briefly discussed.
Susceptibility of the In-shell Brazil Nut Mycoflora and Aflatoxin Contamination to Ozone Gas Treatment during Storage
Barbara Nantua Evangelista Giordano,Janaina Nones,Vildes Maria Scussel
Journal of Agricultural Science , 2012, DOI: 10.5539/jas.v4n8p1
Abstract: The effect on fungi load, toxigenic Aspergillus strains and aflatoxin (AFL) contamination of stored in-shell Brazil nut (Bertholletia excelsa H.B.K.) ozone (O3) gas treated were evaluated. Groups of nuts obtained from retail market were submitted to O3 atmosphere at different concentrations (10, 14, 31.5 mg/l) and stored for 180 days. The O3 treatment affected Brazil nuts mycoflora growth, reduced their moisture content (mc) and degraded AFLs. From the three O3 concentrations applied, 31 mg/l (5 hours exposition) was able to successfully destroy fungi contamination (initial: 4.83 logcfu/g to ng-no grow), including the Aspergillus flavus and A. parasiticus species, since Day One after application. On the other hand, they were still able to grow, at the lower O3 concentrations (10; 14 mg/l), however only in the first days of storage and at reduced number though (from 4.83 to 3.5/3.3 logcfu/g, respectively). Despite of the O3 concentrations applied, AFLs were not detected in all nut samples O3 treated since Day One of application up to the method LOQ of 1.34 μg/kg except for 10 mg/kg). As expected, a reduction of mc (9.43 to 7.32 %) and aw (0.82 to 0.63) due to gas stream application was registered throughout the storage period, which increased with the O3 time of exposure resulting cruncher Brazil nuts. Apart from low cost and simple technology to be applied during storage in-land or in containers before shipping, O3 treatment it is a promising alternative for contamination control and is environment friendly.
Surface-sensitive macrobolometers for the identification of external charged particles
Luca Foggetta,Andrea Giuliani,Claudia Nones,Marisa Pedretti,Samuele Sangiorgio
Physics , 2009, DOI: 10.1063/1.1894608
Abstract: We report the performance of two prototype TeO2 macrobolometers, operated at ~25 mK, able to identify events due to energy deposited at the detector surface. This capability is obtained by thermally coupling thin Ge active layers to the main energy absorber of the bolometer, and is demonstrated by irradiating the detectors with alpha particles. The temperature variations of the main absorber and of the active layer are measured independently with doped Ge thermistors. These results show clearly that an intrinsic limitation of monolithic low temperature calorimeters, e.g., the impossibility to give information about event position, can be efficiently overcome using composite structures.
Current Status and Future Perspectives of the LUCIFER Experiment
J. W. Beeman,F. Bellini,P. Benetti,L. Cardani,N. Casali,D. Chiesa,M. Clemenza,I. Dafinei,S. Di Domizio,F. Ferroni,A. Giachero,L. Gironi,A. Giuliani,C. Gotti,M. Maino,S. Nagorny,S. Nisi,C. Nones,F. Orio,L. Pattavina,G. Pessina,G. Piperno,S. Pirro,E. Previtali,C. Rusconi,M. Tenconi,C. Tomei,M. Vignati
Advances in High Energy Physics , 2013, DOI: 10.1155/2013/237973
Abstract: In the field of fundamental particle physics, the neutrino has become more and more important in the last few years, since the discovery of its mass. In particular, the ultimate nature of the neutrino (if it is a Dirac or a Majorana particle) plays a crucial role not only in neutrino physics, but also in the overall framework of fundamental particle interactions and in cosmology. The only way to disentangle its ultimate nature is to search for the neutrinoless double beta decay. The idea of LUCIFER is to combine the bolometric technique proposed for the CUORE experiment with the bolometric light detection technique used in cryogenic dark matter experiments. The bolometric technique allows an extremely good energy resolution while its combination with the scintillation detection offers an ultimate tool for background rejection. The goal of LUCIFER is not only to build a background-free small-scale experiment but also to directly prove the potentiality of this technique. Preliminary tests on several detectors containing different interesting DBD emitters have clearly demonstrated the excellent background rejection capabilities that arise from the simultaneous, independent, double readout of heat and scintillation light. 1. State of the Art The double beta transition, which is the rarest nuclear weak process, takes place between two even-even isobars, when the decay to the intermediate nucleus is energetically forbidden due to the pairing interaction, which opens a gap between the even-even and the odd-odd mass parabolas in a given isobaric chain. The two-neutrino decay conserves the lepton number and was originally proposed by Goeppert-Mayer in 1935 [1]. It is a second-order weak process—that explains its low rate—and it has been observed for a dozen of nuclei, with lifetimes in the range of 1018–1022?y [2]. Besides the two-neutrino decay, a much more intriguing process, the so-called neutrinoless double beta decay 0 -DBD [3–6], was proposed by Furry [7] shortly after the Majorana theory of the neutrino [8]. In this case, the simultaneous transformation of two neutrons into two protons is accompanied by the emission of two electrons and nothing else. The main feature of 0 -DBD is just the violation of the lepton number. In the modern (standard model) perspective, this is as important as the violation of the baryon number. In full generality, we can imagine this process as a mechanism capable of creating electrons in a nuclear transition. It is remarkable that 0 -DBD is not necessarily due to the exchange of Majorana neutrinos (mass mechanism) as a leading
Double-beta decay investigation with highly pure enriched $^{82}$Se for the LUCIFER experiment
J. W. Beeman,F. Bellini,P. Benetti,L. Cardani,N. Casali,D. Chiesa,M. Clemenza,I. Dafinei,S. Di Domizio,F. Ferroni,L. Gironi,A. Giuliani,C. Gotti,M. Laubenstein,M. Maino,S. Nagorny,S. Nisi,C. Nones,F. Orio,L. Pagnanini,L. Pattavina,G. Pessina,G. Piperno,S. Pirro,E. Previtali,C. Rusconi,K. Sch?ffner,C. Tomei,M. Vignati
Physics , 2015, DOI: 10.1140/epjc/s10052-015-3822-x
Abstract: The LUCIFER project aims at deploying the first array of enriched scintillating bolometers for the investigation of neutrinoless double-beta decay of $^{82}$Se. The matrix which embeds the source is an array of ZnSe crystals, where enriched $^{82}$Se is used as decay isotope. The radiopurity of the initial components employed for manufacturing crystals, that can be operated as bolometers, is crucial for achieving a null background level in the region of interest for double-beta decay investigations. In this work, we evaluated the radioactive content in 2.5 kg of 96.3\% enriched $^{82}$Se metal, measured with a high-purity germanium detector at the Gran Sasso deep underground laboratory. The limits on internal contaminations of primordial decay chain elements of $^{232}$Th, $^{238}$U and $^{235}$U are respectively: $<$61 $\mu$Bq/kg, $< $110 $\mu$Bq/kg and $<$74 $\mu$Bq/kg at 90\% C.L.. The extremely low-background conditions in which the measurement was carried out and the high radiopurity of the $^{82}$Se allowed us to establish the most stringent lower limits on the half-lives of double-beta decay of $^{82}$Se to 0$^+_1$, 2$^+_2$ and 2$^+_1$ excited states of $^{82}$Kr of 3.4$\cdot$10$^{22}$ y, 1.3$\cdot$10$^{22}$ y and 1.0$\cdot$10$^{22}$ y, respectively, with a 90\% C.L..
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