Benchmarking the Particle Background in the Large Hadron Collider Experiments

Background benchmarking measurements have been made to check the low-energy processes which will contribute via nuclear reactions to the radiation background in the LHC experiments at CERN. Previously these processes were only evaluated with Monte Carlo simulations, estimated to be reliable within an uncertainty factor of 2.5. Measurements were carried out in an experimental set-up comparable to the shielding of ATLAS, one of the general-purpose experiments at LHC. The absolute yield and spectral measurements of photons and neutrons emanating from the final stages of the hadronic showers were made with a Bi_4Ge_3O_{12} (BGO) detector. The particle transport code FLUKA was used for detailed simulations. Comparison between measurements and simulations show that they agree within 20% and hence the uncertainty factor resulting from the shower processes can be reduced to a factor of 1.2

Cosmological hydrodynamical simulations of galaxy clusters: X-ray scaling relations and their evolution

We analyse cosmological hydrodynamical simulations of galaxy clusters to study the X-ray scaling relations between total masses and observable quantities such as X-ray luminosity, gas mass, X-ray temperature, and $Y_{X}$. Three sets of simulations are performed with an improved version of the smoothed particle hydrodynamics GADGET-3 code. These consider the following: non-radiative gas, star formation and stellar feedback, and the addition of feedback by active galactic nuclei (AGN). We select clusters with $M_{500} > 10^{14} M_{\odot} E(z)^{-1}$, mimicking the typical selection of Sunyaev-Zeldovich samples. This permits to have a mass range large enough to enable robust fitting of the relations even at $z \sim 2$. The results of the analysis show a general agreement with observations. The values of the slope of the mass-gas mass and mass-temperature relations at $z=2$ are 10 per cent lower with respect to $z=0$ due to the applied mass selection, in the former case, and to the effect of early merger in the latter. We investigate the impact of the slope variation on the study of the evolution of the normalization. We conclude that cosmological studies through scaling relations should be limited to the redshift range $z=0-1$, where we find that the slope, the scatter, and the covariance matrix of the relations are stable. The scaling between mass and $Y_X$ is confirmed to be the most robust relation, being almost independent of the gas physics. At higher redshifts, the scaling relations are sensitive to the inclusion of AGNs which influences low-mass systems. The detailed study of these objects will be crucial to evaluate the AGN effect on the ICM.Comment: 24 pages, 11 figures, 5 tables, replaced to match accepted versio

Mass\u2013metallicity relation from cosmological hydrodynamical simulations and X-ray observations of galaxy groups and clusters

Recent X-ray observations of galaxy clusters show that the distribution of intra-cluster medium (ICM) metallicity is remarkably uniform in space and time. In this paper, we analyse a large sample of simulated objects, from poor groups to rich clusters, to study the dependence of the metallicity and related quantities on the mass of the systems. The simulations are performed with an improved version of the smoothed-particle-hydrodynamic GADGET-3 code and consider various astrophysical processes including radiative cooling, metal enrichment and feedback from stars and active galactic nuclei (AGNs). The scaling between the metallicity and the temperature obtained in the simulations agrees well in trend and evolution with the observational results obtained from two data samples characterized by a wide range of masses and a large redshift coverage. We find that the iron abundance in the cluster core (r < 0.1R500) does not correlate with the temperature nor presents a significant evolution. The scale invariance is confirmed when the metallicity is related directly to the total mass. The slope of the best-fitting relations is shallow (\u3b2 \u2dc -0.1) in the innermost regions (r < 0.5R500) and consistent with zero outside. We investigate the impact of the AGN feedback and find that it plays a key role in producing a constant value of the outskirts metallicity from groups to clusters. This finding additionally supports the picture of early enrichment

Rate effects in high-resolution drift chambers

The impact of high counting rates on the spatial resolution of cylindrical drift tubes is investigated in detail and the results are compared with simulations. Electronics effects and space-charge effects are quantitatively analysed. A spatial resolution of $\sigma < 80\,\mu\mathrm{m}$ can be achieved even at rates as high as 1500\,Hz/cm wire length (300\,kHz per wire)

Resolution limits of drift tubes

Measurements of the drift-tube response to charged particle tracks are compared with a complete simulation. The measured resolution of typically 80\,$\mu$m agrees well with the simulation and allows the individual factors limiting the resolution such as diffusion, charge deposit fluctuations, gas gain fluctuations and signal processing to be studied. The results with respect to the dependence of the drift chamber resolution on gas gain, gas pressure and electronics parameters are reported

Front-end electronics for drift tubes in a high-rate environment

A front-end electronics readout for drift tubes in a high-rate environment is presented. This system allows us to encode several pieces of information (leading edge time, trailing edge time, signal charge and piled-up hits from multiple tracks) into a single readout channel that is presented to the TDC. The advantage of active baseline restoration compared to bipolar signal shaping is discussed

Dependence of Drift Tube Performance on the Anode Wire Diameter

Cylindrical pressurized drift tubes with different anode wire diameters wereoperated in a 170~GeV muon test beam. The dependences of spatialresolution, efficiency and streamer probability on the anode wirediameter were measured. The resolution measurements are compared with a simulation

Viability of transcervical embryo transfer in goats.

Embryo transfer consists in the deposition of the embryo in the recipient uterus. The results of recipient?s fertility vary widely depending on the origin of these embryos: fresh or cryopreserved and produced in vivo or in vitro. Typically, pregnancy rates ranging from 40 to 80% are reported. The objective of this study was to test the feasibility of non-surgical embryo transfer of goat fresh embryos.Proceedings of the 29th Annual Meeting of the Brazilian Embryo Technology Society (SBTE); Gramado, RS, Brazil, August 20th to 23rd, 2015, and 31st Meeting of the European Embryo Transfer Association (AETE); Ghent, Belgium, September 11th and 12th, 2015. Abstract

One and two dimensional analysis of 3pi correlations measured in Pb+Pb interactions

3pi- correlations from Pb+Pb collisions at 158 GeV/c per nucleon are presented as measured by the focusing spectrometer of the NA44 experiment at CERN. The three-body effect is found to be stronger for PbPb than for SPb. The two-dimensional three-particle correlation function is also measured and the longitudinal extension of the source is larger than the transverse extension

Route of Oxytocin administration and nonsurgical embryo recovery in Santa Inês ewes after induction synchronous estrus.

Abstract: Oxytocin has been used to promote cervical dilation with the objective to access uterus both in artificial insemination and transcervical embryo recovery in sheep and goats. The objective of this study was to test the effect of two routes of oxytocin administration on nonsurgical embryo recovery efficiency in Santa Inês ewes after induction of synchronous estrus. A total of 46 pluriparous ewes randomly chosen after weaning received intravaginal sponges (60 mg MAP; Progespon®,Syntex, Buenos Aires, Argentina) for six days plus 200 IU eCG (Novormon 5000®, Syntex, Buenos Aires, Argentina) i.m. and 37.5 ?g d-cloprostenol (Prolise®, ARSA S.R.L., Buenos Aires, Argentina) latero-vulvar, 24 h before sponge removal. Estrus was monitored twice daily after sponge removal and ewes were naturally mated by fertile rams while in estrus. Embryo recovery was attempted by cervical route (Theriogenology, 86:144-151, 2016) at day 7 after estrus onset. A total of 46 ewes that showed estrus received 37.5 ?g d-cloprostenol latero-vulvar and 1 mg estradiol benzoate (Estrogin®, Biofarm, São Paulo, Brazil) i.m. 16 h before embryo recovery and 50 IU oxytocin (5 mL; Ocitocina Forte UCB®, São Paulo, Brazil) 20 min before embryo recovery by i.v. (T1; n = 21) or intravaginal route (T2; n = 21). T2 ewes were kept in anterior bipedal position when sponge applicator was gently introduced into the vulva and vagina and oxytocin was instilled in the vaginal fornix. Applicator was then immediately removed and ewes came back to quadrupedal position. Qualitative data were analyzed by chi-square test, while quantitative data were evaluated by one way ANOVA, both at 5% significance. Overall estrus response was 95.6% (44/46). Two ewes showed estrus later than the others and were not used. Interval to estrus and estrus duration were similar (P > 0.05) for T1 (46.4 ± 11.9 h and 33.8 ± 12.6 h) and T2 (48.0 ± 9.8 h and 31.6 ± 10.8 h) ewes, respectively. Successful uterine flushing was equal to T1 (12/21) and T2 ewes (12/21). Fluid recovery rate was 96.4 and 96.5% for T1 and T2 ewes, respectively (P > 0.05). The duration of the embryo recovery was similar (P > 0.05) for T1 (24.1 ± 5.7 min) and T2 ewes (23.2 ± 5.3 min). The average total structures recovered was 0.9 ± 0.4 for T1 and 0.5 ± 0.5 for T2 ewes (P > 0.05). Results of this study showed that nonsurgical transcervical embryo recovery can be efficiently done in some ewes; a higher number of individuals is needed to conclude that transcervical embryo recovery can be efficiently done in ewes and surgery embryo collections can be avoided in near to 60% of pluriparous Santa Inês ewes; and that the route of oxytocin administration did not affect the parameters evaluated.Proceedings of the 30th Annual Meeting of the Brazilian Embryo Technology Society (SBTE); Foz do Iguaçu, PR, Brazil, August 25th to 27th, 2016, and 32nd Meeting of the European Embryo Transfer Association (AETE); Barcelona, Spain, September 9th and 10th, 2016