1,112 research outputs found

    Strangeness Production in pp,pA,AA Interactions at SPS Energies.HIJING Approach

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    In this report we have made a systematic study of strangeness production in proton-proton(pp),proton-nucleus(pA) and nucleus- nucleus(AA) collisions at CERN Super Proton Synchroton energies, using   HIJING   MONTE   CARLO   MODEL\,\,\, HIJING\,\,\, MONTE \,\,\,CARLO \,\,\,MODEL \\ (version HIJ.01HIJ.01). Numerical results for mean multiplicities of neutral strange particles ,as well as their ratios to negatives hadrons() for p-p,nucleon-nucleon(N-N),\,\,p-S,\,\,p-Ag,\,\,p-Au('min. bias')collisions and p-Au,\,\,S-S,\,\,S-Ag,\,\,S-Au ('central')collisions are compared to experimental data available from CERN experiments and also with recent theoretical estimations given by others models. Neutral strange particle abundances are quite well described for p-p,N-N and p-A interactions ,but are underpredicted by a factor of two in A-A interactions for Λ,Λˉ,KS0\Lambda,\bar{\Lambda}, K^{0}_{S} in symmetric collisions(S-S,\,\,Pb-Pb)and for Λ,Λˉ  \Lambda,\bar{\Lambda}\,\,in asymmetric ones(S-Ag,\,\,S-Au,\,\,S-W). A qualitative prediction for rapidity, transverse kinetic energy and transverse momenta normalized distributions are performed at 200 GeV/Nucleon in p-S,S-S,S-Ag and S-Au collisions in comparison with recent experimental data. HIJING model predictions for coming experiments at CERN for S-Au, S-W and Pb-Pb interactions are given. The theoretical calculations are estimated in a full phase space.Comment: 33 pages(LATEX),18 figures not included,available in hard copy upon request , Dipartamento di Fisica Padova,report DFPD-94-NP-4

    Effect of decreasing dietary crude protein on growth performance, feed efficiency and meat quality of finishing Charolais bulls

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    This study aimed to evaluate the effect of decreasing dietary crude protein (CP) on the performance of finishing Charolais bulls in the Italian rearing system. Animals were fed two diets, differing only in the CP level (low protein (LP), 13.5% CP versus control (CON), 15.0% CP). Dry matter (DM) intake (DMI) and animals\u2019 weights were recorded to obtain average daily gain (ADG) and feed conversion rate (FCR). Feed and fecal samples were collected to evaluate digestibility of diet components. Daily cost of the ration (DRC), feed cost per kg of daily weight gain (CDG) and daily gross margin (DGM) were calculated to analyze the possible benefits of decreasing the protein level. Meat quality analyses were also conducted. Higher DMI (10.6 versus 10 kg/d; p < 0.05) and ADG (1.47 versus 1.36 kg/d; p < 0.05) were observed for CON. No differences in FCR or digestibility were found. Even if the DRC was lower (p < 0.05) for the LP diet (2.26 versus 1.97 \u20ac; CON versus LP), no difference was reported for CDG and DGM. Meat lightness and redness were significantly lower and higher in the LP, respectively. To conclude, the CP requirement in these rearing conditions appeared to be higher than 13.5%

    The Role of Spleen and Liver Elastography and Color-Doppler Ultrasound in the Assessment of Transjugular Intrahepatic Portosystemic Shunt Function

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    The reference standard for assessing transjugular intrahepatic portosystemic shunt (TIPS) function is venography with portosystemic pressure gradient (PPG) measurement. This procedure is invasive and expensive; thus, we assessed the feasibility, reproducibility and diagnostic accuracy of color-Doppler ultrasound (CDUS) and spleen and liver stiffness (LS) measurements for identifying TIPS dysfunction. Twenty-four patients (15 undergoing TIPS placement and nine undergoing TIPS revision) consecutively underwent CDUS examination and LS and spleen stiffness (SS) determination by transient elastography (TE) and point shear-wave elastography (pSWE). All parameters were taken before TIPS placement/revision (1\u201315 d before) and 24 h after, just before revision by venography. pSWE inter-observer agreement was assessed by intra-class correlation coefficient (ICC). CDUS and elastographic data were correlated (Pearson coefficient) with pressure gradients (hepatic venous pressure gradient [HVPG], PPG). Main determinants of TIPS dysfunction were investigated by linear regression. Forty-nine paired examinations were performed in total: 49 (100%) SS reliable measurements by pSWE and 38 (88%) by TE. The ICC for pSWE values was 0.90 (95% confidence interval [CI] 0.81\u20120.94). SS values significantly correlated with HVPG and PPG (R = 0.51, p = 0.01). The area under the Receiver-Operating Characteristic (AUROC) curve of SS for diagnosing TIPS dysfunction was 0.86 (95% CI 0.70\u20120.96) using a 25 kPa cutoff. At multivariate analysis, the flow direction of the intrahepatic portal vein branches and SS values were independently associated to TIPS dysfunction. The intrahepatic portal vein branches flow direction and SS value are two simple, highly sensitive parameters accurately excluding TIPS dysfunction. SS measurement by pSWE is feasible, reproducible and both positively and significantly correlates with HVPG and PPG values

    Influence of Ageing Time and Method on Beef Quality and Safety

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    The effectiveness of dry ageing with regard to retaining meat quality is still subject to debate. At 4 d post mortem, samples of boneless strip loins were excised from young Charolais carcasses and then stored for a further 26 d in a cooler, either vacuum-packaged (VP) or dried-aged (DA). Loin samples were also dissected 7 d post mortem as a control treatment (CT). Chemical, instrumental and microbiological data (n = 18) were determined in longissimus dorsi and underwent ANOVA to estimate the differences in the ageing fixed factor split into two orthogonal contrasts: control vs. aged and VP vs. DA. Ageing loss (both surface dehydration and water purge) was greater in DA compared to VP samples, resulting in the lowest moisture content and highest crude protein and fat percentage in DA loins. The ageing method did not affect meat surface colour, except for redness, which had the lowest value in DA samples. Meat tenderness improved a similar amount following both VP and DA ageing treatments. Compared to the control, prolonged ageing raised both the peroxide value and the total microbial count, especially in DA samples, though both remained within the recommended limits. In summation, both ageing methods improved beef meat tenderisation, preserving its shelf life

    Cloning, purification, and biochemical characterization of an esterase from Aspergillus nidulans

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    A large accumulation of agro-industrial waste from different segments is generated daily and is often not properly managed. There are now other fronts in research to give a destination to these residues; these studies are generally aimed at obtaining new and better enzymes and the formulation of enzymatic cocktails that contain (for example, cellulases and hemicellulases) responsible for the degradation of lignocellulosic material. The plant cell wall is mainly composed of cellulose, hemicellulose, and lignin, forming a complex structure. Xylan is one of the main constituents of hemicellulose. To degrade this structure, enzymatic hydrolysis must occur synergistically with xylanolytic enzymes, such as endo-beta-1,4-xylanases, -xylosidases, and acetyl xylan esterase (AXE). In the current work, we reported the purification and biochemical characterization of an acetyl xylan esterase (AxeCE3) from Aspergillus nidulans. The axeCE3 gene was cloned into the pEXPYR vector and transformed into A. nidulans A773 for protein expression. The enzyme AxeCE3 was purified and characterized for its biochemical properties. AxeCE3 showed activity over a wide range of pH (3.0-9.0) and temperature (30-70 °C), with maximum activity at 55 °C, pH 7.0. Regarding the stability at temperature, AxeCE3 showed values above 90% of residual activity after 24 h of incubation at 45 and 50 °C. In relation to stability at pH, AxeCE3 maintained more than 90% of its residual activity after being incubated at 25 °C for 24 h between the pH range 3.0 to 9.0. It was also verified the effect of possible inhibitors (ethylenediamine tetraacetic acid (EDTA), Furfural, and 5- Hydroxymethylfurfural (5-HMF)) on the enzyme activity. AxeCE3 maintained 88% of relative activity at 5 mM EDTA, 43% and 82% at 50 mM furfural and 5-HMF, respectively. The results showed that AxeCE3 has interesting properties to use in the development in the formulation of enzymatic cocktails for the hydrolysis of lignocellulosic residues.The work was supported by the following: FAPESP (São Paulo Research Foundation, grants: 2014/50884 and 2018/07522-6) and National Institute of Science and Technology of Bioethanol, INCT, CNPq (grant: 465319/2014-9) and process 301963/2017-7. Research scholarships were granted to RCA and DA by FAPESP (Grant No: 2020/00081-4 and No: 2020/15510-8), to GSA by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Finance Code 001).info:eu-repo/semantics/publishedVersio

    Performance of ALICE pixel prototypes in high energy beams

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    The two innermost layers of the ALICE inner tracking system are instrumented with silicon pixel detectors. Single chip assembly prototypes of the ALICE pixels have been tested in high energy particle beams at the CERN SPS. Detection efficiency and spatial precision have been studied as a function of the threshold and the track incidence angle. The experimental method, data analysis and main results are presented.Comment: 10 pages, 9 figures, contribution to PIX2005 Workshop, Bonn (Germany), 5-8 September 200

    Beam Test Performance and Simulation of Prototypes for the ALICE Silicon Pixel Detector

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    The silicon pixel detector (SPD) of the ALICE experiment in preparation at the Large Hadron Collider (LHC) at CERN is designed to provide the precise vertex reconstruction needed for measuring heavy flavor production in heavy ion collisions at very high energies and high multiplicity. The SPD forms the innermost part of the Inner Tracking System (ITS) which also includes silicon drift and silicon strip detectors. Single assembly prototypes of the ALICE SPD have been tested at the CERN SPS using high energy proton/pion beams in 2002 and 2003. We report on the experimental determination of the spatial precision. We also report on the first combined beam test with prototypes of the other ITS silicon detector technologies at the CERN SPS in November 2004. The issue of SPD simulation is briefly discussed.Comment: 4 pages, 5 figures, prepared for proceedings of 7th International Position Sensitive Detectors Conference, Liverpool, Sept. 200

    Discriminant analysis of pyrrolizidine alkaloid contamination in bee pollen based on near-infrared data from lab-stationary and portable spectrometers

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    Bee pollen may be contaminated with pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs), which are mainly detected by liquid chromatography coupled to tandem mass spectrometry (LC\u2013MS/MS), even though the use of fast near-infrared (NIR) spectroscopy is an ongoing alternative. Therefore, the main challenge of this study was to assess the feasibility of both a lab-stationary (Foss) and a portable (Polispec) NIR spectrometer in 60 dehydrated bee pollen samples. After an ANOVA-feature selection of the most informative NIR spectral data, canonical discriminant analysis (CDA) was performed to distinguish three quantitative PA/PANO classes (\ub5g/kg): 400, high. According to the LC\u2013MS/MS analysis, 77% of the samples were contaminated with PAs/PANOs and the sum content of the 17 target analytes was higher than 400\ua0\ub5g/kg in 28% of the samples. CDA was carried out on a pool of 18 (Foss) and 22 (Polispec) selected spectral variables and allowed accurate classification of samples from the low class as confirmed by the high values of Matthews correlation coefficient ( 65 0.91) for both NIR spectrometers. Leave-one-out cross-validation highlighted precise recognition of samples characterised by a high PA/PANO content with a low misclassification rate (0.02) as false negatives. The most informative wavelengths were within the 2400\ua0nm regions for Foss and > 1500\ua0nm for Polispec that could be associated with cyclic amines, and epoxide chemical structures of PAs/PANOs. In sum, both lab-stationary and portable NIR systems are reliable and fast techniques for detecting PA/PANO contamination in bee pollen
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