3,293 research outputs found
An economic assessment of alternative antimicrobial use scenarios on pig farms
This paper explores the theoretical economic outcome of management changes that result in different levels of antimicrobial use (AMU) in two types of UK pig farm. A static farm economic pig production model (FEPM) was used on a representative âTop-thirdâ most profitable farm and a representative âMid-rangeâ profitable farm. Three AMU theoretical management scenarios were investigated; (a) management changes leading to a reduction of AMU by 35% (AMU35); (b) more extensive management changes leading to a reduction of AMU by 95% (AMU95); and (c) implementing depopulation of the herd (AMU Depop). A sensitivity analysis was conducted to determine the effect of increases or decreases in pig revenue and feed price on farm gross margin under these scenarios. Over a single year, the AMU35 scenario was estimated to have a small positive impact (+3%) on both farm types. The other two AMU reduction scenarios had higher AMU reduction on farms but required higher variable cost and hence they resulted in lower farm profitability. There was a substantial reduction (up to â50%) in farm gross margin under these two AMU reduction scenarios in the modeled short-term time-period. The impact of the alternative AMU scenarios was slightly higher on a farm representing the âTop-thirdâ farm type, reducing farm gross margin further by 7% compared to the âMid-rangeâ farm. Nevertheless, both farm types stay profitable under all three AMU scenarios. The results showed that in the modeled short-term implementing management changes that result in a reduction of on-farm AMU by 35% had a good economic outcome. In practice, the other two scenarios would be considered as longer-term strategies. Although both require higher initial costs to implement, the improved biosecurity and hygiene will benefit from lower disease occurrence for a longer term. Farm gross margins were, however, found to be highly sensitive to changes on market prices especially increasing feed prices. An increase of more than 15% in feed price moved a profitable farm into a loss-making farm. It will be economically challenging for uptakes of these, or similar, AMU reduction scenarios on farms if the market prices become un-favorable to pig farmers
Altered maternal profiles in corticotropin-releasing factor receptor 1 deficient mice
BACKGROUND: During lactation, the CNS is less responsive to the anxiogenic neuropeptide, corticotropin-releasing factor (CRF). Further, central injections of CRF inhibit maternal aggression and some maternal behaviors, suggesting decreased CRF neurotransmission during lactation supports maternal behaviors. In this study, we examined the maternal profile of mice missing the CRF receptor 1 (CRFR1). Offspring of knockout (CRFR1-/-) mice were heterozygote to offset possible deleterious effects of low maternal glucocorticoids on pup survival and all mice contained a mixed 50:50 inbred/outbred background to improve overall maternal profiles and fecundity. RESULTS: Relative to littermate wild-type (WT) controls, CRFR1-/- mice exhibited significant deficits in total time nursing, including high arched-back, on each test day. Consistent with decreased nursing, pups of CRFR1-deficient dams weighed significantly less than WT offspring. Licking and grooming of pups was significantly higher in WT mice on postpartum Day 2 and when both test days were averaged, but not on Day 3. Time off nest was higher for CRFR1-/- mice on Day 2, but not on Day 3 or when test days were averaged. Licking and grooming of pups did not differ on Day 2 when this measure was examined as a proportion of time on nest. CRFR1-/- mice showed significantly higher nest building on Day 3 and when tests were averaged. Mean pup number was almost identical between groups and no pup mortality occurred. Maternal aggression was consistently lower in CRFR1-/- mice and in some measures these differences approached, but did not reach significance. Because of high variance, general aggression results are viewed as preliminary. In terms of sites of attacks on intruders, CRFR1-/- mice exhibited significantly fewer attacks to the belly of the intruder on Day 5 and when tests were averaged. Performance on the elevated plus maze was similar between genotypes. Egr-1 expression differences in medial preoptic nucleus and c-Fos expression differences in bed nucleus of stria terminalis between genotype suggest possible sites where loss of gene alters behavioral output. CONCLUSION: Taken together, the results suggest that the presence of an intact CRFR1 receptor supports some aspects of nurturing behavior
Myocardial infarction with normal coronary arteries: a case report and review of the literature
<p>Abstract</p> <p>Introduction</p> <p>Although acute myocardial infarction is generally associated with obstructive coronary artery disease, myocardial infarction associated with normal coronary arteries is a well-known condition. The overall prevalence rate of myocardial infarction with normal coronary arteries is considered to be low, varying from 1% to12% depending on the definition of "normal" coronary arteries.</p> <p>Case presentation</p> <p>We describe here a case of a 49-year-old woman with a history of prior myocardial infarction who continued to be asymptomatic after a 10-year follow-up, in the absence of a high-risk profile for adverse outcomes. She was studied with multi-slice coronary computed tomography and whole-body angiography, which showed normal coronary and extra-coronary arteries.</p> <p>Conclusion</p> <p>This case report raises two important issues. First, the possible role of multi-slice computed tomography/coronary angiography in the risk- and prognosis assessment of patients with known or suspected coronary artery disease. Second, the important role played by long-term pharmacological therapy in patients with prior myocardial infarction and normal coronary arteries.</p
Genetic parameters for faecal egg count, packed-cell volume and body-weight in Santa InĂȘs lambs
Worm infection is one of the main factors responsible for economic losses in sheep breeding in Brazil. Random regression analysis was used to estimate genetic parameters for the factors faecal egg-count (FEC), packed-cell volume (PCV) and body weight (BW) in Santa InĂȘs lambs. Data from 119 female, offspring of nine rams, were collected between December, 2005 and December, 2006, from the experimental flock of Embrapa Tabuleiros Costeiros, the Brazilian Agricultural Research Corporation located in Frei Paulo, SE, Brazil. After weaning, females were drenched until the faecal egg count had dropped to zero. Two natural challenges were undertaken. FEC heritability was extremely variable, this increasing from 0.04 to 0.27 in the first challenge and from 0.01 to 0.52 during the second. PCV heritability peaks were 0.31 and 0.12 in the first and second challenges, respectively. In the second challenge, BW heritability was close to 0.90. The genetic correlations among these traits did not differ from zero. There is the possibility of increasing parasite resistance in Santa InĂȘs by selecting those animals with lower FEC. Selection to increase resistance will not adversely affect lamb-growth, although lambs with a slow growth-rate may be more susceptible to infection
The EMBLA survey - metal-poor stars in the Galactic bulge
Cosmological models predict the oldest stars in the Galaxy should be found closest to the centre of the potential well, in the bulge. The Extremely Metal-poor BuLge stars with AAOmega survey (EMBLA) successfully searched for these old, metal-poor stars by making use of the distinctive SkyMapper photometric filters to discover candidate metal-poor stars in the bulge. Their metal-poor nature was then confirmed using the AAOmega spectrograph on the Anglo-Australian Telescope. Here we present an abundance analysis of 10 bulge stars with â2.8 < [Fe/H] < â1.7 from MIKE/Magellan observations, in total determining the abundances of 22 elements. Combining these results with our previous high-resolution data taken as part of the Gaia-ESO Survey, we have started to put together a picture of the chemical and kinematic nature of the most metal-poor stars in the bulge. The currently available kinematic data are consistent with the stars belonging to the bulge, although more accurate measurements are needed to constrain the starsâ orbits. The chemistry of these bulge stars deviates from that found in halo stars of the same metallicity. Two notable differences are the absence of carbon-enhanced metal-poor bulge stars, and the α element abundances exhibit a large intrinsic scatter and include stars which are underabundant in these typically enhanced elements.LMH and MA have been supported by the Australian Research Council (grant FL110100012). ARC acknowledges support from the European Union FP7 programme through ERC grant number 320360. DY is supported through an Australian Research Council Future Fellowship (FT140100554). Research on metal-poor stars with SkyMapper is supported through Australian Research Council Discovery Projects grants DP120101237 and DP150103294 (PI: Da Costa). This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This paper includes data gathered with the 6.5 metre Magellan Telescopes located at Las Campanas Observatory, Chile.This is the final version of the article. It first appeared from Oxford University Press via http://dx.doi.org/10.1093/mnras/stw100
Maternal-calf relationships and their influence on calves up to 120 days
Objectives. To research parental behavior and measure the weight of Nelore and Guzerat calves up to 120 days of age, collecting data from birth up to the first lactation. Materials and methods. Seven different corporal positions were considered to obtain specific data for each of the following categories: time to stand (TP), time to intend to feed after standing (TPTM), weight at birth (PN), weight at 120 days (P120), and time in contact with the calf (TCC). Additionally, independent variables were also evaluated, organized by class: weight at birth (CPN), number of calvings (CNP), order of calving in relation with the herd (CLPR), time of calving (CHP), and finally, hindering to feed (CTAT). Results. There was a significant result in favor of the Nelore race over the Guzerat race. The statistical averages for Nelore and Guzerat were: Time to stand averaged 71 and 153 minutes; time to intend to feed after standing, 39 minutes for Nelore and of 114 minutes for Guzerat. For variable weight at 120 days, Nelore reached an average of 122 kg, and Guzerat 109 kg. For the time in contact with the calf variable there was no significant variance between races. Conclusions. Results showed the superiority of the Nelore race, considering it better adapted to local environmental conditions. Key words: Behavior, calves, suckling, well being (Source: CAB)
Maternal-calf relationships and their influence on calves up to 120 days
Objectives. To research parental behavior and measure the weight of Nelore and Guzerat calves up to 120 days of age, collecting data from birth up to the first lactation. Materials and methods. Seven different corporal positions were considered to obtain specific data for each of the following categories: time to stand (TP), time to intend to feed after standing (TPTM), weight at birth (PN), weight at 120 days (P120), and time in contact with the calf (TCC). Additionally, independent variables were also evaluated, organized by class: weight at birth (CPN), number of calvings (CNP), order of calving in relation with the herd (CLPR), time of calving (CHP), and finally, hindering to feed (CTAT). Results. There was a significant result in favor of the Nelore race over the Guzerat race. The statistical averages for Nelore and Guzerat were: Time to stand averaged 71 and 153 minutes; time to intend to feed after standing, 39 minutes for Nelore and of 114 minutes for Guzerat. For variable weight at 120 days, Nelore reached an average of 122 kg, and Guzerat 109 kg. For the time in contact with the calf variable there was no significant variance between races. Conclusions. Results showed the superiority of the Nelore race, considering it better adapted to local environmental conditions.
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Key words: Behavior, calves, suckling, well being (Source: CAB)
A single low-energy, iron-poor supernova as the source of metals in the star SMSS J 031300.36-670839.3
The element abundance ratios of four low-mass stars with extremely low
metallicities indicate that the gas out of which the stars formed was enriched
in each case by at most a few, and potentially only one low-energy, supernova.
Such supernovae yield large quantities of light elements such as carbon but
very little iron. The dominance of low-energy supernovae is surprising, because
it has been expected that the first stars were extremely massive, and that they
disintegrated in pair-instability explosions that would rapidly enrich galaxies
in iron. What has remained unclear is the yield of iron from the first
supernovae, because hitherto no star is unambiguously interpreted as
encapsulating the yield of a single supernova. Here we report the optical
spectrum of SMSS J031300.36- 670839.3, which shows no evidence of iron (with an
upper limit of 10^-7.1 times solar abundance). Based on a comparison of its
abundance pattern with those of models, we conclude that the star was seeded
with material from a single supernova with an original mass of ~60 Mo (and that
the supernova left behind a black hole). Taken together with the previously
mentioned low-metallicity stars, we conclude that low-energy supernovae were
common in the early Universe, and that such supernovae yield light element
enrichment with insignificant iron. Reduced stellar feedback both chemically
and mechanically from low-energy supernovae would have enabled first-generation
stars to form over an extended period. We speculate that such stars may perhaps
have had an important role in the epoch of cosmic reionization and the chemical
evolution of early galaxies.Comment: 28 pages, 6 figures, Natur
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