32 research outputs found
Phenotypic association among performance, feed efficiency and methane emission traits in Nellore cattle.
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
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
CUPID is a next-generation bolometric experiment aiming at searching for
neutrinoless double-beta decay with ~250 kg of isotopic mass of Mo. It
will operate at 10 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 Mo-enriched LiMoO 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 Ba source with one light detector achieving
0.71(5) keV FWHM, which is -- to our knowledge -- the best ever obtained when
compared to 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 LiMoO scintillating bolometers for CUPID and CROSS experiments
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, Bq/kg, level of the LMO crystals
radioactive contamination by Th and Ra.Comment: Prepared for submission to JINST; 23 pages, 9 figures, and 4 table
Real-Time Detection of Covert Channels in Highly Virtualized Environments
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
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 Decay of Te with CUORE
CUORE is a large scale cryogenic experiment searching for neutrinoless double beta decay () in Te. The CUORE detector is made of natural tellurium, providing the possibility of rare event searches on isotopes other than Te. In this work we describe a search for neutrinoless positron emitting electron capture () decay in Te with a total TeO exposure of 355.7 kg yr, corresponding to 0.2405 kg yr of Te. Albeit with two final state electrons represents the most promising channel, the emission of a positron and two 511-keV s make 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 yr at 90% Credibility Interval (C.I.). After unblinding we find no evidence of signal and set a 90% C.I. Bayesian lower limit of yr on Te half-life. This result improves by an order of magnitude the existing limit from the combined analysis of CUORE-0 and Cuoricino