956 research outputs found

    Unified Models of Molecular Emission from Class 0 Protostellar Outflow Sources

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    Low mass star-forming regions are more complex than the simple spherically symmetric approximation that is often assumed. We apply a more realistic infall/outflow physical model to molecular/continuum observations of three late Class 0 protostellar sources with the aims of (a) proving the applicability of a single physical model for all three sources, and (b) deriving physical parameters for the molecular gas component in each of the sources. We have observed several molecular species in multiple rotational transitions. The observed line profiles were modelled in the context of a dynamical model which incorporates infall and bipolar outflows, using a three dimensional radiative transfer code. This results in constraints on the physical parameters and chemical abundances in each source. Self-consistent fits to each source are obtained. We constrain the characteristics of the molecular gas in the envelopes as well as in the molecular outflows. We find that the molecular gas abundances in the infalling envelope are reduced, presumably due to freeze-out, whilst the abundances in the molecular outflows are enhanced, presumably due to dynamical activity. Despite the fact that the line profiles show significant source-to-source variation, which primarily derives from variations in the outflow viewing angle, the physical parameters of the gas are found to be similar in each core.Comment: MNRAS 12 pages, 16 figure

    Women's experiences of factors that facilitate or inhibit gestational diabetes self-management

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    BACKGROUND: Gestational diabetes rates have increased dramatically in the past two decades and this pattern of increase appears to relate primarily to the obesity epidemic, older maternal age and migration from world areas of high GDM risk. Women from disadvantaged and migrant backgrounds are most at risk of developing and of mismanaging this condition. The aim of the study was to explore the factors that facilitated or inhibited gestational diabetes self-management among women in a socially deprived area. METHODS: Fifteen pregnant women, with a diagnosis of gestational diabetes, were purposively recruited for this study. Qualitative semi structured interviews and 1 focus group were conducted when participants were approximately 28–38 weeks gestation. The study’s theoretical framework was based on interpretative phenomenology and data was analysed using a thematic analysis approach. RESULTS: Women in this study identified a number of factors that complicated their task of GDM self-management. Barriers included: (1) time pressures; (2) physical constraints; (3) social constraints; (4) limited comprehension of requirements, and (5) insulin as an easier option. Factors facilitating GDM self-management included: thinking about the baby and psychological support from partners and families. CONCLUSION: Women from low socio economic and migrant backgrounds often struggle to comprehend GDM self-management requirements. To improve adherence to management plans, these women require educational and supportive services that are culturally appropriate and aimed at a low level of literacy

    Development and initial testing of a GDM information website for multi-ethnic women with GDM

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    BACKGROUND: Gestational diabetes mellitus (GDM) affects approximately 5–15 % of pregnant women in Australia. Highest rates are seen among women who are obese, from specific ethnic backgrounds and low socio-economic circumstance. These features also impact on uptake of self-management recommendations. GDM that is not well managed can give rise to serious pregnancy complications. The aim of this project was to develop and test an intervention to improve knowledge of GDM and GDM self-management principles. METHODS: A web-based intervention, consisting of resources aimed at a low level of literacy, was developed and tested among multi-ethnic women at a metropolitan hospital in Melbourne Australia. A basic one-group pre-test/post-test design was used to explore the impact of the intervention on knowledge, in 3 domains: (1) Knowledge of GDM; (2) food values, and;(3) GDM self-management principles. Questionnaire data was analysed using Statistical Package for the Social Sciences (SPSS), version 21.0. Fisher’s exact test was used to test for an improvement in each knowledge scale. RESULTS: Twenty-one women with GDM, from multi-ethnic backgrounds, participated in the testing of the intervention. Results indicated that the intervention was effective at improving knowledge scores and this effect was greatest in the first domain, knowledge of GDM. Although some improvement of knowledge scores occurred in the other two domains, food values and self-management principles, these improvements were less than expected. This finding may relate to a number of misunderstandings in the interpretation of the web resource and survey questions. These issues will need to be resolved prior to proceeding to a clinical trial. CONCLUSION: Initial results from this study look promising and suggest that with some improvements, the intervention could prove a useful adjunct support for women with GDM from multi-ethnic and low socio-economic backgrounds. Conducting a randomised controlled trial is feasible in the future and will provide a useful means of examining efficacy of the intervention

    Improving and disaggregating N2O emission factors for ruminant excreta on temperate pasture soils

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    pre-printCattle excreta deposited on grazed grasslands are a major source of the greenhouse gas (GHG) nitrous oxide (N2O). Currently, many countries use the IPCC default emission factor (EF) of 2% to estimate excreta-derived N2O emissions. However, emissions can vary greatly depending on the type of excreta (dung or urine), soil type and timing of application. Therefore three experiments were conducted to quantify excreta-derived N2O emissions and their associated EFs, and to assess the effect of soil type, season of application and type of excreta on the magnitude of losses. Cattle dung, urine and artificial urine treatments were applied in spring, summer and autumn to three temperate grassland sites with varying soil and weather conditions. Nitrous oxide emissions were measured from the three experiments over 12 months to generate annual N2O emission factors. The EFs from urine treated soil was greater (0.30–4.81% for real urine and 0.13–3.82% for synthetic urine) when compared with dung (− 0.02–1.48%) treatments. Nitrous oxide emissions were driven by environmental conditions and could be predicted by rainfall and temperature before, and soil moisture deficit after application; highlighting the potential for a decision support tool to reduce N2O emissions by modifying grazing management based on these parameters. Emission factors varied seasonally with the highest EFs in autumn and were also dependent on soil type, with the lowest EFs observed from well-drained and the highest from imperfectly drained soil. The EFs averaged 0.31 and 1.18% for cattle dung and urine, respectively, both of which were considerably lower than the IPCC default value of 2%. These results support both lowering and disaggregating EFs by excreta type.This research was financially supported under the National Development Plan, through the Research Stimulus Fund, administered by the Department of Agriculture, Food and the Marine (Grant numbers RSF10/RD/SC/716 and 11S138)

    Proteomic Insights into the Hidden World of Phloem Sap Feeding

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    The physical interface between a phloem-feeding insect and its host plant is a single cell buried deep within the plant tissue. As such, the molecular interactions between these notorious agricultural pests and the crop plants upon which they feed are diffi cult to study. ‘Omic’ technologies have proved crucial in revealing some of the fascinating detail of the molecular interplay between these partners. Here we review the role of proteomics in identifying putative components of the secreted saliva of phloem-feeding insects, particularly aphids, and discuss the limited knowledge concerning the function of these proteins
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