912 research outputs found
Effects of non-steroidal growth implant and dietary zilpaterol hydrochloride on growth and carcass characteristics of feedlot lambs
The effects of steroidal growth implants alone or in combination with ÎČ-adrenergic agonist feed additives have not been studied thoroughly in mutton sheep in South African feedlot conditions. This study investigated the effects of a non-steroidal growth implant zeranol (RalgroÂź), alone or in combination with zilpaterol hydrochloride (ZilmaxÂź), on growth performance, carcass characteristics, and selected meat quality traits in 160 SA Mutton Merino ram lambs fed in a commercial feedlot. The experimental design consisted of two Ralgro treatment groups x two Zilmax treatments x two Zilmax feeding periods x 20 animals per treatment group. Lambs were randomly allocated to eight treatment groups, of which one half were implanted with Ralgro after arrival, followed by feed supplementation with Zilmax at two Zilmax feeding periods during the finisher phase, compared with negative control treatments (e.g. no Ralgro or Zilmax; Ralgro + no Zilmax; or no Ralgro + Zilmax). All lambs were fed the grower ration traditionally used by the commercial feedlot, which contained 16.89% crude protein (CP) and 2.94 Mcal/kg dry matter (DM). Zilmax was supplemented in the feed at 40 mg per animal per day and fed for 18 days or 25 days, plus three days withdrawal. Lambs that did not receive the Zilmax treatment were fed the basal diet without Zilmax feed supplementation. Ralgro significantly increased average daily gains (ADG) and cold carcass mass (CCM) of lambs. Lambs supplemented with Zilmax during the finisher phase had higher ADG, greater CCM and increased dressing percentage by ca.1.1% compared with those in the control group. Lambs fed Zilmax for 25 days had higher CCM than those fed for 18 days. The duration of the Zilmax treatment also decreased hide weight, fat thickness and shear force values (tenderness). Zilmax increased ADG and CCM in lambs, particularly if combined with Ralgro implants during the growing phase. The results from this study indicate that the combination of Ralgro implants with Zilmax feed supplementation during the finisher phase had additive effects and increased ADG and CCM of feedlot lambs.Keywords: Growth performance, meat quality, South African Mutton Merino, sheep, RalgroÂź, Zilmax
Exact Renormalization Group for O(4) Gauged Supergravity
We study exact renormalization group (RG) in O(4) gauged supergravity using
the effective average action formalism. The nonperturbative RG equations for
cosmological and newtonian coupling constants are found. It is shown the
existence of (nonstable) fixed point of these equations. The solution of RG
equation for newtonian coupling constant is qualitatively the same as in
Einstein gravity(i.e. it is growing at large distances).Comment: Latex file, 11 page
Comparison between the effects of zilpaterol hydrochloride and R-salbutamol fed during the finishing period on the growth and carcass characteristics of feedlot cattle
This study aimed to compare the effects of feeding 60 mg of the ÎČ-adrenergic agonist, zilpaterol
HCl (ZilmaxÂź), per steer per day versus feeding 120 mg of the ÎČ-adrenergic agonist, R-salbutamol
(SalbutamateÂź10%), per steer per day for the last 30 days of the finishing period on the growth,
efficiency, and carcass characteristics of 228 typical South African feedlot steers in a completely
randomised control study. The steers were slaughtered at the same abattoir after a 3-day withdrawal
period. The growth and feedlot parameters included starting mass, slaughter mass, average daily
gain, live mass gain, and lean carcass gain. The carcass characteristics included warm (WCW) and
cold carcass mass (CCW), carcass length (CL), subcutaneous fat thickness measured over the 13th
rib (SCF), dressing percentage, carcass compactness, carcass classification score, age code, and
fat code using the South African carcass classification system. The inclusion of zilpaterol HCl as a
feed additive resulted in higher growth and efficiency, with an ADG of 1.3 kg/day (P <0.05) in steers
fed zilpaterol HCl compared to 1.1 kg/day for steers fed R-salbutamol. Steers in the zilpaterol HCl
experimental group had a 12.5 kg higher average slaughter mass, yielding ~3 kg higher calculated
lean gain than steers fed R-salbutamol. Steers fed zilpaterol HCl yielded better carcass
characteristics of 11.4 kg higher CCW and marginally longer carcasses compared to steers fed Rsalbutamol.
Therefore, the overall growth, feedlot performance, and carcass characteristics were
higher in the zilpaterol HCl-fed steers than in R-salbutamol-fed steers.http://www.sasas.co.zaam2024Animal and Wildlife SciencesSDG-02:Zero Hunge
Factors affecting success of conservation translocations of terrestrial vertebrates: a global systematic review
Translocationâmoving individuals for release in different locationsâis among the most important conservation interventions for increasing or re-establishing populations of threatened species. However, translocations often fail. To improve their effectiveness, we need to understand the features that distinguish successful from failed translocations. We assembled and analysed a global database of translocations of terrestrial vertebrates (n = 514) to assess the effects of various design features and extrinsic factors on success. We analysed outcomes using standardised metrics: a categorical success/failure classification; and population growth rate. Probability of categorical success and population growth rate increased with the total number of individuals released but with diminishing returns above about 20â50 individuals. Positive outcomesâcategorical success and high population growthâwere less likely for translocations in Oceania, possibly because invasive species are a major threat in this region and are difficult to control at translocation sites. Rates of categorical success and population growth were higher in Europe and North America than elsewhere, suggesting the key role of context in positive translocation outcomes. Categorical success has increased throughout the 20th century, but that increase may have plateaued at about 75% since about 1990. Our results suggest there is potential for further increase in the success of conservation translocations. This could be best achieved by greater investment in individual projects, as indicated by total number of animals released, which has not increased over time.Shane D. Morris, Barry W. Brook, Katherine E. Moseby, Christopher N. Johnso
Tumour inflammatory infiltrate predicts survival following curative resection for node-negative colorectal cancer
<b>Background</b>: A pronounced tumour inflammatory infiltrate is known to confer a good outcome in colorectal cancer. Klintrup and colleagues reported a structured assessment of the inflammatory reaction at the invasive margin scoring low grade or high grade. The aim of the present study was to examine the prognostic value of tumour inflammatory infiltrate in node-negative colorectal cancer.
<b>Methods</b>: Two hundred patients had undergone surgery for node-negative colorectal cancer between 1997 and 2004. Specimens were scored with Jassâ and Klintrupâs criteria for peritumoural infiltrate. Pathological data were taken from the reports at that time.
<b>Results</b>: Low-grade inflammatory infiltrate assessed using Klintrupâs criteria was an independent prognostic factor in node-negative disease. In patients with a low-risk Petersen Index (n = 179), low-grade infiltrate carried a threefold increased risk of cancer death. Low-grade infiltrate was related to increasing T stage and an infiltrating margin.
<b>Conclusion</b>: Assessment of inflammatory infiltrate using Klintrupâs criteria provides independent prognostic information on node-negative colorectal cancer. A high-grade local inflammatory response may represent effective host immune responses impeding tumour growth
A Compact Beam Stop for a Rare Kaon Decay Experiment
We describe the development and testing of a novel beam stop for use in a
rare kaon decay experiment at the Brookhaven AGS. The beam stop is located
inside a dipole spectrometer magnet in close proximity to straw drift chambers
and intercepts a high-intensity neutral hadron beam. The design process,
involving both Monte Carlo simulations and beam tests of alternative beam-stop
shielding arrangements, had the goal of minimizing the leakage of particles
from the beam stop and the resulting hit rates in detectors, while preserving
maximum acceptance for events of interest. The beam tests consisted of
measurements of rates in drift chambers, scintilation counter hodoscopes, a gas
threshold Cherenkov counter, and a lead glass array. Measurements were also
made with a set of specialized detectors which were sensitive to low-energy
neutrons, photons, and charged particles. Comparisons are made between these
measurements and a detailed Monte Carlo simulation.Comment: 39 pages, 14 figures, submitted to Nuclear Instruments and Method
Anion exchange membrane soil nitrate predicts turfgrass color and yield.
Desirable nitrogen (N) management practices for turfgrass supply sufficient N for high quality turf while limiting excess soil N. Previous studies suggested the potential of anion exchange membranes (AEMs) for predicting turfgrass color, quality, or yield. However, these studies suggested a wide range of critical soil nitrate-nitrogen (NO3-N) values across sample dates. A field experiment, in randomized complete block design with treatments consisting of nine N application rates, was conducted on a mixed species cool-season turfgrass lawn across two growing seasons. Every 2 wk from May to October, turfgrass color was assessed with three different reflectance meters, and soil NO3-N was measured with in situ AEMs. Cate-Nelson models were developed comparing relative reflectance value and yield to AEM desorbed soil NO3-N pooled across all sample dates. These models predicted critical AEM soil NO3-N values from 0. 45 to 1.4 micro g cm-2 d-1. Turf had a low probability of further positive response to AEM soil NO3-N greater than these critical values. These results suggest that soil NO3-N critical values from AEMs may be applicable across sample dates and years and may serve to guide N fertilization to limit excess soil NO3-N
On the Progenitors of Core-Collapse Supernovae
Theory holds that a star born with an initial mass between about 8 and 140
times the mass of the Sun will end its life through the catastrophic
gravitational collapse of its iron core to a neutron star or black hole. This
core collapse process is thought to usually be accompanied by the ejection of
the star's envelope as a supernova. This established theory is now being tested
observationally, with over three dozen core-collapse supernovae having had the
properties of their progenitor stars directly measured through the examination
of high-resolution images taken prior to the explosion. Here I review what has
been learned from these studies and briefly examine the potential impact on
stellar evolution theory, the existence of "failed supernovae", and our
understanding of the core-collapse explosion mechanism.Comment: 7 Pages, invited review accepted for publication by Astrophysics and
Space Science (special HEDLA 2010 issue
Simulating MOS science on the ELT: Lyα forest tomography
Mapping the large-scale structure through cosmic time has numerous applications in studies of cosmology and galaxy evolution. At zââłâ2, the structure can be traced by the neutral intergalactic medium (IGM) by way of observing the Lyα forest towards densely sampled lines of sight of bright background sources, such as quasars and star-forming galaxies. We investigate the scientific potential of MOSAIC, a planned multi-object spectrograph on the European Extremely Large Telescope (ELT), for the 3D mapping of the IGM at zââłâ3. We simulated a survey of 3ââČâzââČâ4 galaxies down to a limiting magnitude of mrââŒâ25.5 mag in an area of 1 degree2 in the sky. Galaxies and their spectra (including the line-of-sight Lyα absorption) were taken from the lightcone extracted from the Horizon-AGN cosmological hydrodynamical simulation. The quality of the reconstruction of the original density field was studied for different spectral resolutions (Râ=â1000 and Râ=â2000, corresponding to the transverse typical scales of 2.5 and 4 Mpc) and signal-to-noise ratios (S/N) of the spectra. We demonstrate that the minimum S/N (per resolution element) of the faintest galaxies that a survey like this has to reach is S/Nâ=â4. We show that a survey with this sensitivity enables a robust extraction of cosmic filaments and the detection of the theoretically predicted galaxy stellar mass and star-formation rate gradients towards filaments. By simulating the realistic performance of MOSAIC, we obtain S/N(Tobs,âR,âmr) scaling relations. We estimate that âČ35 (65) nights of observation time are required to carry out the survey with the instrumentâs high multiplex mode and with a spectral resolution of Râ=â1000 (2000). A survey with a MOSAIC-concept instrument on the ELT is found to enable the mapping of the IGM at zâ> â3 on Mpc scales, and as such will be complementary to and competitive with other planned IGM tomography surveys
Electroweak instantons as a solution to the ultrahigh energy cosmic ray puzzle
We propose a scenario in which a simple power-like primary spectrum for
protons with sources at cosmological distances leads to a quantitative
description of all the details of the observed cosmic ray spectrum for energies
from 10^{17} eV to 10^{21} eV. As usual, the ultrahigh energy protons with
energies above E_{GZK} ~ 4 x 10^{19} eV loose a large fraction of their
energies by the photoproduction of pions on the cosmic microwave background,
which finally decay mainly into neutrinos. In our scenario, these so-called
cosmogenic neutrinos interact with nucleons in the atmosphere through Standard
Model electroweak instanton-induced processes and produce air showers which are
hardly distinguishable from ordinary hadron-initiated air showers. In this way,
they give rise to a second contribution to the observed cosmic ray spectrum --
in addition to the one from above mentioned protons -- which reaches beyond
E_{GZK}. Since the whole observed spectrum is uniquely determined by a single
primary injection spectrum, no fine tuning is needed to fix the ratio of the
spectra below and above E_{GZK}. The statistical analysis shows an excellent
goodness of this scenario. Possible tests of it range from observations at
cosmic ray facilities and neutrino telescopes to searches for QCD
instanton-induced processes at HERA.Comment: 14 pages, 7 figure
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