592 research outputs found

    Whole genome integrity and enhanced developmental potential in ram freeze-dried spermatozoa at mild sub-zero temperature

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    Freeze-dried spermatozoa typically shows a reduction in fertility primarily due to the DNA damage resulting from the sublimation process. In order to minimize the physical/mechanical damage resulting from lyophilization, here we focused on the freezing phase, comparing two cooling protocols: (i) rapid-freezing, where ram sperm sample is directly plunged into liquid nitrogen (LN-group), as currently done; (ii) slow-freezing, where the sample is progressively cooled to − 50 °C (SF-group). The spermatozoa dried in both conditions were analysed to assess residual water content by Thermal Gravimetric Analysis (TGA) and DNA integrity using Sperm Chromatin Structure Assay (SCSA). TGA revealed more than 90% of water subtraction in both groups. A minor DNA damage, Double-Strand Break (DSB) in particular, characterized by a lower degree of abnormal chromatin structure (Alpha-T), was detected in the SF-group, comparing to the LN-one. In accordance with the structural and DNA integrity data, spermatozoa from SF-group had the best embryonic development rates, comparing to LN-group: cleaved embryos [42/100 (42%) versus 19/75 (25.3%), P < 0.05, SL and LN respectively] and blastocyst formation [7/100 (7%) versus 2/75 (2.7%), P < 0.05, SF and LN respectively]. This data represents a significant technological advancement for the development of lyophilization as a valuable and cheaper alternative to deep-freezing in LN for ram semen

    Projected Quasi-particle Perturbation theory

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    The BCS and/or HFB theories are extended by treating the effect of four quasi-particle states perturbatively. The approach is tested on the pairing hamiltonian, showing that it combines the advantage of standard perturbation theory valid at low pairing strength and of non-perturbative approaches breaking particle number valid at higher pairing strength. Including the restoration of particle number, further improves the description of pairing correlation. In the presented test, the agreement between the exact solution and the combined perturbative + projection is almost perfect. The proposed method scales friendly when the number of particles increases and provides a simple alternative to other more complicated approaches

    Estimation of the exposure for the air shower detection mode of EUSO-SPB1

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    EUSO-SPB1 was a balloon-borne pathfinder mission of the JEM-EUSO (Joint Experiment Missions for the Extreme Universe Space Observatory) program. A 12-day long flight started from New Zealand on April 25th, 2017 on-board the NASA's Super Pressure Balloon. With capability of detecting EeV energy air showers, the data acquisition was performed using a 1 m^2 two-Fresnel-lens UV-sensitive telescope with fast readout electronics in the air shower detection mode over ~30 hours at ~16--30 km above South Pacific. Using a variety of approaches, we searched for air shower events. Up to now, no air shower events have been identified. The effective exposure, regarding the role of the clouds in particular, was estimated based on the air shower and detector simulations together with a numerical weather forecast model. Compared with the case assuming the fully clear atmosphere conditions, more than ~60% of showers are detectable regardless the presence of the clouds. The studies in the present work will be applied in the follow-up pathfinders and in the future full-scale missions in the JEM-EUSO program

    NEMO: A Project for a km3^3 Underwater Detector for Astrophysical Neutrinos in the Mediterranean Sea

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    The status of the project is described: the activity on long term characterization of water optical and oceanographic parameters at the Capo Passero site candidate for the Mediterranean km3^3 neutrino telescope; the feasibility study; the physics performances and underwater technology for the km3^3; the activity on NEMO Phase 1, a technological demonstrator that has been deployed at 2000 m depth 25 km offshore Catania; the realization of an underwater infrastructure at 3500 m depth at the candidate site (NEMO Phase 2).Comment: Proceeding of ISCRA 2006, Erice 20-27 June 200

    Measurement of the atmospheric muon flux with the NEMO Phase-1 detector

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    The NEMO Collaboration installed and operated an underwater detector including prototypes of the critical elements of a possible underwater km3 neutrino telescope: a four-floor tower (called Mini-Tower) and a Junction Box. The detector was developed to test some of the main systems of the km3 detector, including the data transmission, the power distribution, the timing calibration and the acoustic positioning systems as well as to verify the capabilities of a single tridimensional detection structure to reconstruct muon tracks. We present results of the analysis of the data collected with the NEMO Mini-Tower. The position of photomultiplier tubes (PMTs) is determined through the acoustic position system. Signals detected with PMTs are used to reconstruct the tracks of atmospheric muons. The angular distribution of atmospheric muons was measured and results compared with Monte Carlo simulations.Comment: Astrop. Phys., accepte

    Science of atmospheric phenomena with JEM-EUSO

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    The main goal of the JEM-EUSO experiment is the study of Ultra HighEnergy Cosmic Rays (UHECR, 10^19 - 10^21 eV ), but the method which will be used (detection of the secondary light emissions induced by cosmic rays in the atmosphere) allows to study other luminous phenomena. The UHECRs will be detected through the measurement of the emission in the range between 290 and 430 m, where some part of Transient Luminous Events (TLEs) emission also appears. This work discusses the possibility of using the JEM-EUSO Telescope to get new scientific results on TLEs. The high time resolution of this instrument allows to observe the evolution of TLEs with great precision just at the moment of their origin. Thepaper consists of four parts: review of the present knowledge on the TLE, presentation of the results of the simulations of the TLE images in the JEM-EUSO telescope, results of the Russian experiment Tatiana-2 and discussion of the possible progress achievable in this field with JEM-EUSO as well as possible cooperation with other space projects devoted to the study of TLE-TARANIS and ASIM. In atmospheric physics, the study of TLEs became one of the main physical subjects of interest after their discovery in 1989. In the years 1992 - 1994 detection was performed fromsatellite, aircraft and space shuttle and recently from the International Space Station. These events have short duration (milliseconds) and small scales (km to tens of km) and appear at altitudes 50 - 100 km. Their nature is still not clear and each new experimental data can be useful for a better understanding of these mysterious phenomena.Fil: Adams, J. H.. University of Alabama in Huntsville; Estados UnidosFil: Ahmad, S.. Ecole Polytechnique; FranciaFil: Albert, J. N.. Univ Paris-Sud; FranciaFil: Allard, D.. Univ Paris Diderot; FranciaFil: Anchordoqui, L.. University of Wisconsin-Milwaukee; Estados UnidosFil: Andreev, V.. University of California; Estados UnidosFil: Anzalone, A.. INAF - Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo; ItaliaFil: Arai, Y.. High Energy Accelerator Research Organization (KEK); JapónFil: Asano, K.. Tokyo Institute of Technology; JapónFil: Ave Pernas, M.. Universidad de Alcala (UAH); EspañaFil: Barrillon, P.. Univ Paris-Sud; FranciaFil: Batsch, T.. Skobeltsyn Institute of Nuclear Physics; RusiaFil: Bayer, J.. University of Tubingen; AlemaniaFil: Bechini, R.. Universita’ di Torino; ItaliaFil: Belenguer, T.. Instituto Nacional de Tecnica Aeroespacial (INTA); EspañaFil: Bellotti, R.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Belov, K.. University of California; Estados UnidosFil: Berlind, A. A.. Vanderbilt University; Estados UnidosFil: Bertaina, M.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Biermann, P. L.. Karlsruhe Institute of Technology (KIT); AlemaniaFil: Biktemerova, S.. Joint Institute for Nuclear Research; RusiaFil: Blaksley, C.. Univ Paris Diderot; FranciaFil: Blanc, N.. Swiss Center for Electronics and Microtechnology (CSEM); SuizaFil: Blecki, J.. Space Research Centre of the Polish Academy of Sciences (CBK; PoloniaFil: Blin-Bondil, S.. Ecole Polytechnique; FranciaFil: Blumer, J.. Karlsruhe Institute of Technology (KIT),; AlemaniaFil: Bobik, P.. Institute of Experimental Physics; EslovaquiaFil: Bogomilov, M.. University of Sofia; BulgariaFil: Bonamente, M.. University of Alabama in Huntsville; Estados UnidosFil: Supanitsky, Alberto Daniel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: The JEM-EUSO Collaboration

    An evaluation of the exposure in nadir observation of the JEM-EUSO mission

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    We evaluate the exposure during nadir observations with JEM-EUSO, the Extreme Universe Space Observatory,on-board the Japanese Experiment Module of the International Space Station. Designed as a mission to explore the extreme energy Universe from space, JEM-EUSO will monitor the Earth's nighttime atmosphere to record the ultraviolet light from tracks generated by extensive air showers initiated by ultra-high energy cosmic rays. In the present work, we discuss the particularities of space-based observation and we compute the annual exposure in nadir observation. The results are based on studies of the expected trigger aperture and observational duty cycle, as well as, on the investigations of the effects of clouds and different types of background light. We show that the annual exposure is about one order of magnitude higher than those of the presently operating ground-based observatories.Fil: Adams, J. H.. University of Alabama in Huntsville; Estados UnidosFil: Ahmad, S.. Universite Paris Sud; FranciaFil: Albert, J. N..Fil: Allard, D.. Universite Paris Diderot - Paris 7; FranciaFil: Ambrosio, M.. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Anchordoqui, L.. Medical College Of Wisconsin; Estados UnidosFil: Anzalone, A.. INAF; ItaliaFil: Arai, Y.. High Energy Accelerator Research Organization (KEK); JapónFil: Aramo, C..Fil: Asano, K.. Interactive Research Center of Science, Tokyo Institute of Technology; JapónFil: Ave, M.. Universidad de Santiago de Compostela; EspañaFil: Barrillon, P.. Universite de Paris; FranciaFil: Batsch, T.. National Centre for Nuclear Research; PoloniaFil: Bayer, J.. University of Tubingen; AlemaniaFil: Belenguer, T.. j Instituto Nacional de Técnica Aeroespacial (INTA); EspañaFil: Bellotti, R.. Universita’ degli Studi di Bari Aldo Moro and INFN; ItaliaFil: Berlind, A. A.. Vanderbilt University; Estados UnidosFil: Bertaina, M.. Universita di Torino; ItaliaFil: Biermann, P. L.. Karlsruhe Institute of Technology (KIT); AlemaniaFil: Biktemerova,. Joint Institute for Nuclear Research; RusiaFil: Blaksley, C.. Universite de la Sorbona Nouvelle; FranciaFil: Blecki, J.. Space Research Centre of the Polish Academy of Sciences (CBK); PoloniaFil: Blin-Bondil, S.. Universite de Paris; FranciaFil: Blumer, J.. Karlsruhe Institute of Technology (KIT),; AlemaniaFil: Bobik, P.. Institute of Experimental Physics; EslovaquiaFil: Bogomilov, M.. St. Kliment Ohridski University of Sofia; BulgariaFil: Bonamente, M.. University of Alabama in Huntsville; Estados UnidosFil: Briz, S.. Universidad Carlos III de Madrid,; EspañaFil: Supanitsky, Alberto Daniel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin
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