814 research outputs found
Neonatal oxytocin administration and weaning onto a gruel based diet reduce weight loss at weaning and enhance gastric leptin expression
Administering oxytocin to neonatal rats has positive long-term effects on growth and development (Uvnas-Moberg and Petersson, 2005). These effects include a reduction in the stress response to weaning, increased post-weaning feed intake and alterations in the expression of gastrointestinal (GI) hormones regulating feed intake (Uvnas-Moberg et al., 1998; Sohlstrom et al., 1999). Two GI hormones of importance in regulating feed intake are ghrelin and leptin, which have antagonistic actions. Ghrelin expression is increased in response to fasting and leptin expression increases rapidly in response to feed intake. Since weaning the piglet is associated with stress and growth restriction, this study examined whether oxytocin given to young pigs could reduce the extent of the post-weaning growth check, along with any associated changes in ghrelin and leptin expression
Animal welfare indicators for sheep during sea transport: The effect of voyage day and time of day
Ensuring the well-being of animals during transport is becoming an increasingly important societal concern. The Australian livestock export industry recognises the need for comprehensive monitoring and reporting on animal welfare during sea transport. It is predicted that pen-side assessments of sheep can be used to monitor environmental conditions, resource access, and animal health and behavioural outcomes throughout a sea voyage. Pen-side assessments by observation are non-invasive and practical to apply in an industry setting. This study monitored sheep using a pilot list of welfare indicators during two sea voyages from Australia to the Middle East, in contrasting seasons. Sheep behaviour, environment and resources were recorded three times daily via pen-side observations of six pens of Merino wethers (castrated males), repeated over three decks for each voyage. Behavioural outcomes were examined for the effect of sampling frequency on group assessments. The number of behavioural measures were reduced via Principal Component (PC) analysis. The primary three PC factors were tested against the time of sampling and pen location after accounting for the effect of environmental- and resource-based predictor variables. PC 1 (24.0 % of the total variance) described activity levels, with sheep on Voyage B being more active in the morning and resting or recumbent in the middle of the afternoon and evening. PC 2 (14.7 %) reflected heat responses with the majority of the variation in these data accounted for by changes in Wet Bulb Globe Temperature (WBGT) and manure pad moisture. The heat responses described by PC 2 also varied by voyage day (p < 0.001) and time point (p < 0.001). PC 3 scores (9.5 %) reflected flight distances and feeding behaviour and strongly correlated to WBGT and pellet consumption per head per day. Feeding behaviour generally became more competitive, and flight distances reduced as both voyages progressed. Results indicate that a comprehensive welfare monitoring protocol requires repeated daily sampling throughout a voyage. The findings of this study are pertinent for developing a sampling strategy to assess sheep welfare during sea transport
Aerial Survey Estimates of Abundance of the Eastern Chukchi Sea Stock of Beluga Whales (Delphinapterus leucas) in 2012
The eastern Chukchi Sea (ECS) stock of beluga whales is one of three stocks in western Alaska that are co-managed by the National Marine Fisheries Service and the Alaska Beluga Whale Committee. Abundance of this stock was estimated as 3710 in 1991 from incomplete data. Analysis of data from satellite-linked time-depth recorders (SDRs) attached to belugas in summer concentration areas of the ECS and Beaufort Sea (BS) stocks provided an overview of beluga distribution and movements and allowed the identification of an area (140˚ W to 157˚ W in the BS) and a time period (19 July – 20 August) in which the distributions of the two stocks do not overlap. Aerial survey data were collected by the Aerial Surveys of Arctic Marine Mammals (ASAMM) project in that region and time period in 2012. We used those data in a line transect analysis that estimated there were 5547 (CV = 0.22) surface-visible belugas in the study area. Data from SDRs were used to develop correction factors to account for animals that were missed because they were either outside of the study area or diving too deep to be seen, resulting in a total abundance estimate of 20 752 (CV = 0.70). The average annual Alaska Native subsistence harvest from the ECS stock (57) is about 0.3% of the population estimate. Without data collected by the ASAMM project and from satellite-linked tags, this analysis would not have been possible. Additional surveys and tagging of ECS belugas are warranted.Le stock de bélugas de l’est de la mer des Tchouktches (EMT) figure parmi les trois stocks de l’ouest de l’Alaska à être gérés conjointement par le National Marine Fisheries Service et l’Alaska Beluga Whale Committee. À partir de données incomplètes, l’abondance de ce stock a été estimée à 3 710 en 1991. L’analyse des données recueillies à l’aide d’enregistreurs de profondeur temporelle satellitaires (SDR) fixés aux bélugas dans les zones de concentration estivales de l’EMT et de la mer de Beaufort (MB) a permis d’obtenir un aperçu de la répartition et du déplacement des bélugas ainsi que de cerner une zone (de 140˚ O à 157˚ O dans la MB) et une période (du 19 juillet au 20 août) pour lesquelles la répartition des deux stocks ne se chevauchent pas. Le projet Aerial Surveys of Arctic Marine Mammals (ASAMM) a permis de recueillir des données à partir de levés aériens pour la région et la période concernées en 2012. Grâce à une analyse de lignes interceptées, ces données ont permis d’estimer qu’il y avait 5 547 (CV = 0,22) bélugas visibles à la surface dans la zone à l’étude. Les données en provenance de SDR ont servi à mettre au point des facteurs de correction pour tenir compte des bélugas qui n’ont pas été captés, soit parce qu’ils se trouvaient en dehors de la zone visée par l’étude, soit parce qu’ils plongeaient trop loin pour être vus, ce qui s’est traduit par une estimation totale d’abondance de 20 752 (CV = 0,70) bélugas. La prise de subsistance annuelle moyenne de stock (57) par les Autochtones de l’Alaska dans l’EMT correspond à environ à 0,3 % de l’estimation de la population. Cette analyse n’aurait pu être possible sans les données prélevées par le projet ASAMM et les SDR. D’autres levés et l’étiquetage des bélugas de l’EMT s’imposent
The contribution of qualitative behavioural assessment to appraisal of livestock welfare
Animal welfare is increasingly important for the Australian livestock industries, to maintain social licence to practice as well as ensuring market share overseas. Improvement of animal welfare in the livestock industries requires several important key steps. Paramount among these, objective measures are needed for welfare assessment that will enable comparison and contrast of welfare implications of husbandry procedures or housing options. Such measures need to be versatile (can be applied under a wide range of on- and off-farm situations), relevant (reveal aspects of the animal’s affective or physiological state that is relevant to their welfare), reliable (can be repeated with confidence in the results), relatively economic to apply, and they need to have broad acceptance by all stakeholders. Qualitative Behavioural Assessment (QBA) is an integrated measure that characterises behaviour as a dynamic, expressive body language. QBA is a versatile tool requiring little specialist equipment suiting application to in situ assessments that enables comparative, hypothesis-driven evaluation of various industry-relevant practices. QBA is being increasingly used as part of animal welfare assessments in Europe, and although most other welfare assessment methods record ‘problems’ (e.g. lameness, injury scores, and so on), QBA can capture positive aspects of animal welfare (e.g. positively engaged with their environment, playfulness). In this viewpoint, we review the outcomes of recent QBA studies and discuss the potential application of QBA, in combination with other methods, as a welfare assessment tool for the Australian livestock industries
Review of livestock welfare indicators relevant for the Australian live export industry
Animal welfare is an important issue for the live export industry (LEI), in terms of economic returns, community attitudes and international socio-political relations. Mortality has traditionally been the main welfare measure recorded within the LEI; however, high mortality incidents are usually acted upon after adverse events occur, reducing the scope for proactive welfare enhancement. We reviewed 71 potential animal welfare measures, identifying those measures that would be appropriate for use throughout the LEI for feeder and slaughter livestock species, and categorised these as animal-, environment- and resource-based. We divided the live export supply chain into three sectors: (1) Australian facilities, (2) vessel and (3) destination country facilities. After reviewing the relevant regulations for each sector of the industry, we identified 38 (sector 1), 35 (sector 2) and 26 (sector 3) measures already being collected under current practice. These could be used to form a ‘welfare information dashboard’: a LEI-specific online interface for collecting data that could contribute towards standardised industry reporting. We identified another 20, 25 and 28 measures that are relevant to each LEI sector (sectors 1, 2, 3, respectively), and that could be developed and integrated into a benchmarking system in the future
Melting of the glacier base during a small-volume subglacial rhyolite eruption: evidence from Blahnukur, Iceland.
Although observations of recent volcanic eruptions beneath Vatnajokull, Iceland have improved the understanding of ice deformation and meltwater drainage, little is known about the processes that occur at the glacier base. We present observations of the products of a small-volume, effusive subglacial rhyolite eruption at Blahnukur, Torfajokull, Iceland. Lava bodies, typically 7 m long, have unusual conical morphologies and columnar joint orientations that suggest emplacement within cavities melted into the base of a glacier. Cavities appear to have been steep-walled and randomly distributed. These features can be explained by a simple model of conductive heat loss during the ascent of a lava body to the glacier base. The released heat melts a cavity in the overlying ice. The development of vapour-escape pipes in the waterlogged, permeable breccias surrounding the lava allows rapid heat transfer between lava and ice. The formed meltwater percolates into the breccias, recharging the cooling system and leaving a steam-filled cavity. The slow ascent rates of intrusive rhyolitic magma bodies provide ample time for a cavity to be melted in the ice above, even during the final 10 m of ascent to the glacier base. An equilibrium cavity size is calculated at which melting is balanced by creep closure. This is dependent upon the heat input and the difference between glaciostatic and cavity pressure. The cavity sizes inferred from Blahnukur are consistent with a pressure differential of 2-4 MPa, suggesting that the ice was at least 200 m thick. This is consistent with the volcanic stratigraphy, which indicates that the ice exceeded 350 m in thickness. Although this is the first time that a subglacial cavity system of this type has been reconstructed from an ancient volcanic sequence, it shares many characteristics with the modern firn cave system formed by fumarolic melting within the summit crater of Mount Rainier, Washington. At both localities, it appears that localised heating at the glacier base has resulted in heterogeneous melting patterns. Despite the different rheological properties of ice and firn, similar patterns of cavity roof deformation are inferred. The development of low-pressure subglacial cavities in regions of high heat flux may influence the trajectory of rising magma, with manifold implications for eruptive mechanisms and resultant subglacial volcanic landforms
Healthcare-associated outbreak of meticillin-resistant Staphylococcus aureus bacteraemia: role of a cryptic variant of an epidemic clone
BACKGROUND
New strains of meticillin-resistant Staphylococcus aureus (MRSA) may be associated with changes in rates of disease or clinical presentation. Conventional typing techniques may not detect new clonal variants that underlie changes in epidemiology or clinical phenotype.
AIM
To investigate the role of clonal variants of MRSA in an outbreak of MRSA bacteraemia at a hospital in England.
METHODS
Bacteraemia isolates of the major UK lineages (EMRSA-15 and -16) from before and after the outbreak were analysed by whole-genome sequencing in the context of epidemiological and clinical data. For comparison, EMRSA-15 and -16 isolates from another hospital in England were sequenced. A clonal variant of EMRSA-16 was identified at the outbreak hospital and a molecular signature test designed to distinguish variant isolates among further EMRSA-16 strains.
FINDINGS
By whole-genome sequencing, EMRSA-16 isolates during the outbreak showed strikingly low genetic diversity (P < 1 × 10(-6), Monte Carlo test), compared with EMRSA-15 and EMRSA-16 isolates from before the outbreak or the comparator hospital, demonstrating the emergence of a clonal variant. The variant was indistinguishable from the ancestral strain by conventional typing. This clonal variant accounted for 64/72 (89%) of EMRSA-16 bacteraemia isolates at the outbreak hospital from 2006.
CONCLUSIONS
Evolutionary changes in epidemic MRSA strains not detected by conventional typing may be associated with changes in disease epidemiology. Rapid and affordable technologies for whole-genome sequencing are becoming available with the potential to identify and track the emergence of variants of highly clonal organisms
A complete 3D numerical study of the effects of pseudoscalar-photon mixing on quasar polarizations
We present the results of three-dimensional simulations of quasar
polarizations in the presence of pseudoscalar-photon mixing in the
intergalactic medium. The intergalactic magnetic field is assumed to be
uncorrelated in wave vector space but correlated in real space. Such a field
may be obtained if its origin is primordial. Furthermore we assume that the
quasars, located at cosmological distances, have negligible initial
polarization. In the presence of pseudoscalar-photon mixing we show, through a
direct comparison with observations, that this may explain the observed large
scale alignments in quasar polarizations within the framework of big bang
cosmology. We find that the simulation results give a reasonably good fit to
the observed data.Comment: 15 pages, 8 figures, significant changes, to appear in EPJ
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