32 research outputs found

    Phenotypic association among performance, feed efficiency and methane emission traits in Nellore cattle.

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    Enteric methane (CH4) emissions are a natural process in ruminants and can result in up to 12% of energy losses. Hence, decreasing enteric CH4 production constitutes an important step towards improving the feed efficiency of Brazilian cattle herds. The aim of this study was to evaluate the relationship between performance, residual feed intake (RFI), and enteric CH4 emission in growing Nellore cattle (Bos indicus). Performance, RFI and CH4 emission data were obtained from 489 animals participating in selection programs (mid-test age and body weight: 414±159 days and 356±135 kg, respectively) that were evaluated in 12 performance tests carried out in individual pens (n = 95) or collective paddocks (n = 394) equipped with electronic feed bunks. The sulfur hexafluoride tracer gas technique was used to measure daily CH4 emissions. The following variables were estimated: CH4 emission rate (g/day), residual methane emission and emission expressed per mid-test body weight, metabolic body weight, dry matter intake (CH4/DMI), average daily gain, and ingested gross energy (CH4/GE). Animals classified as negative RFI (RFI0). Nonetheless, more efficient animals emitted more CH4/DMI and CH4/GE (P < 0.0001), suggesting that the difference in daily intake between animals is a determinant factor for the difference in daily enteric CH4 emissions. In addition, animals classified as negative RFI emitted less CH4 per kg mid-test weight and metabolic weight (P = 0.0096 and P = 0.0033, respectively), i.e., most efficient animals could emit less CH4 per kg of carcass. In conclusion, more efficient animals produced less methane when expressed as g/day and per kg mid-test weight than less efficient animals, suggesting lower emissions per kg of carcass produced. However, it is not possible to state that feed efficiency has a direct effect on enteric CH4 emissions since emissions per kg of consumed dry matter and the percentage of gross energy lost as CH4 are higher for more efficient animals

    Status and prospects of discovery of 0νββ decay with the CUORE detector

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    In this contribution we present the achievements of the CUORE experiment so far. It is the first tonne-scale bolometric detector and it is in stable data taking since 2018. We reached to collect about 1800 kg×yr of exposure of which more than 1ton×year have been analysed. The CUORE detector is meant to search for the neutrinoless double β decay (0νββ) of the 130Te isotope. This is a beyond Standard Model process which could establish the nature of the neutrino to be Dirac or a Majorana particle. It is an alternative mode of the two-neutrinos double β decay, a rare decay which have been precisely measured by CUORE in the 130Te. We found no evidence of the 0νββ and we set a Bayesian lower limit of 2.2×1025yr on its half-life. The expertise achieved by CUORE set a milestone for any future bolometric detector, including CUPID, which is the planned next generation experiment searching for 0νββ with scintillating bolometers

    A first test of CUPID prototypal light detectors with NTD-Ge sensors in a pulse-tube cryostat

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    CUPID is a next-generation bolometric experiment aiming at searching for neutrinoless double-beta decay with ~250 kg of isotopic mass of 100^{100}Mo. It will operate at \sim10 mK in a cryostat currently hosting a similar-scale bolometric array for the CUORE experiment at the Gran Sasso National Laboratory (Italy). CUPID will be based on large-volume scintillating bolometers consisting of 100^{100}Mo-enriched Li2_2MoO4_4 crystals, facing thin Ge-wafer-based bolometric light detectors. In the CUPID design, the detector structure is novel and needs to be validated. In particular, the CUORE cryostat presents a high level of mechanical vibrations due to the use of pulse tubes and the effect of vibrations on the detector performance must be investigated. In this paper we report the first test of the CUPID-design bolometric light detectors with NTD-Ge sensors in a dilution refrigerator equipped with a pulse tube in an above-ground lab. Light detectors are characterized in terms of sensitivity, energy resolution, pulse time constants, and noise power spectrum. Despite the challenging noisy environment due to pulse-tube-induced vibrations, we demonstrate that all the four tested light detectors comply with the CUPID goal in terms of intrinsic energy resolution of 100 eV RMS baseline noise. Indeed, we have measured 70--90 eV RMS for the four devices, which show an excellent reproducibility. We have also obtained outstanding energy resolutions at the 356 keV line from a 133^{133}Ba source with one light detector achieving 0.71(5) keV FWHM, which is -- to our knowledge -- the best ever obtained when compared to γ\gamma detectors of any technology in this energy range.Comment: Prepared for submission to JINST; 16 pages, 7 figures, and 1 tabl

    Twelve-crystal prototype of Li2_2MoO4_4 scintillating bolometers for CUPID and CROSS experiments

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    An array of twelve 0.28 kg lithium molybdate (LMO) low-temperature bolometers equipped with 16 bolometric Ge light detectors, aiming at optimization of detector structure for CROSS and CUPID double-beta decay experiments, was constructed and tested in a low-background pulse-tube-based cryostat at the Canfranc underground laboratory in Spain. Performance of the scintillating bolometers was studied depending on the size of phonon NTD-Ge sensors glued to both LMO and Ge absorbers, shape of the Ge light detectors (circular vs. square, from two suppliers), in different light collection conditions (with and without reflector, with aluminum coated LMO crystal surface). The scintillating bolometer array was operated over 8 months in the low-background conditions that allowed to probe a very low, μ\muBq/kg, level of the LMO crystals radioactive contamination by 228^{228}Th and 226^{226}Ra.Comment: Prepared for submission to JINST; 23 pages, 9 figures, and 4 table

    Real-Time Detection of Covert Channels in Highly Virtualized Environments

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    Part 3: INFRASTRUCTURE SECURITYInternational audienceDespite extensive research, covert channels are a principal threat to information security. Covert channels employ specially-crafted content or timing characteristics to transmit internal information to external attackers. Most techniques for detecting covert channels model legitimate network traffic. However, such an approach may not be applicable in dynamic virtualized environments because traffic for modeling normal activities may not be available.This paper describes Observer, a real-time covert channel detection system. The system runs a secure virtual machine that mimics the vulnerable virtual machine so that any differences between two virtual machines can be identified in real time. Unlike other detection systems, Observer does not require historic data to construct a model. Experimental tests demonstrate that Observer can detect covert channels with a high success rate and low latency and overhead

    Twelve-crystal prototype of Li2MoO4 scintillating bolometers for CUPID and CROSS experiments

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    An array of twelve 0.28 kg lithium molybdate (LMO) low-temperature bolometers equipped with 16 bolometric Ge light detectors, aiming at optimization of detector structure for CROSS and CUPID double-beta decay experiments, was constructed and tested in a low-background pulse-tube-based cryostat at the Canfranc underground laboratory in Spain. Performance of the scintillating bolometers was studied depending on the size of phonon NTD-Ge sensors glued to both LMO and Ge absorbers, shape of the Ge light detectors (circular vs. square, from two suppliers), in different light collection conditions (with and without reflector, with aluminum coated LMO crystal surface). The scintillating bolometer array was operated over 8 months in the low-background conditions that allowed to probe a very low, μBq/kg, level of the LMO crystals radioactive contamination by 228Th and 226Ra

    Search for Neutrinoless β+EC\beta^+EC Decay of 120^{120}Te with CUORE

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    CUORE is a large scale cryogenic experiment searching for neutrinoless double beta decay (0νββ0\nu\beta\beta) in 130^{130}Te. The CUORE detector is made of natural tellurium, providing the possibility of rare event searches on isotopes other than 130^{130}Te. In this work we describe a search for neutrinoless positron emitting electron capture (0νβ+EC0\nu\beta^+EC) decay in 120^{120}Te with a total TeO2_2 exposure of 355.7 kg \cdot yr, corresponding to 0.2405 kg \cdot yr of 120^{120}Te. Albeit 0νββ0 \nu \beta^-\beta^- with two final state electrons represents the most promising channel, the emission of a positron and two 511-keV γ\gammas make 0νβ+EC0\nu\beta^+EC decay signature extremely clear. To fully exploit the potential offered by the detector modularity we include events with different topology and perform a simultaneous fit of five selected signal signatures. Using blinded data we extract a median exclusion sensitivity of 3.410223.4 \cdot 10^{22} yr at 90% Credibility Interval (C.I.). After unblinding we find no evidence of 0νβ+EC0\nu\beta^+EC signal and set a 90% C.I. Bayesian lower limit of 2.910222.9 \cdot 10^{22} yr on 120^{120}Te half-life. This result improves by an order of magnitude the existing limit from the combined analysis of CUORE-0 and Cuoricino
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