3,938 research outputs found

    Variable mixer propulsion cycle

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    A design technique, method and apparatus are delineated for controlling the bypass gas stream pressure and varying the bypass ratio of a mixed flow gas turbine engine in order to achieve improved performance. The disclosed embodiments each include a mixing device for combining the core and bypass gas streams. The variable area mixing device permits the static pressures of the core and bypass streams to be balanced prior to mixing at widely varying bypass stream pressure levels. The mixed flow gas turbine engine therefore operates efficiently over a wide range of bypass ratios and the dynamic pressure of the bypass stream is maintained at a level which will keep the engine inlet airflow matched to an optimum design level throughout a wide range of engine thrust settings

    Reduction of Ion Heating During Magnetic Reconnection by Large-Scale Effective Potentials

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    The physical processes that control the partition of released magnetic energy between electrons and ions during reconnection is explored through particle-in-cell simulations and analytical techniques. We demonstrate that the development of a large-scale parallel electric field and its associated potential controls the relative heating of electrons and ions. The potential develops to restrain heated exhaust electrons and enhances their heating by confining electrons in the region where magnetic energy is released. Simultaneously the potential slows ions entering the exhaust below the Alfv\'enic speed expected from the traditional counterstreaming picture of ion heating. Unexpectedly, the magnitude of the potential and therefore the relative partition of energy between electrons and ions is not a constant but rather depends on the upstream parameters and specifically the upstream electron normalized temperature (electron beta). These findings suggest that the fraction of magnetic energy converted into the total thermal energy may be independent of upstream parameters

    Examining the complementarity between the ERIC compilation of implementation strategies and the behaviour change technique taxonomy: A qualitative analysis

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    BACKGROUND: Efforts to generate evidence for implementation strategies are frustrated by insufficient description. The Expert Recommendations for Implementing Change (ERIC) compilation names and defines implementation strategies; however, further work is needed to describe the actions involved. One potentially complementary taxonomy is the behaviour change techniques (BCT) taxonomy. We aimed to examine the extent and nature of the overlap between these taxonomies. METHODS: Definitions and descriptions of 73 strategies in the ERIC compilation were analysed. First, each description was deductively coded using the BCT taxonomy. Second, a typology was developed to categorise the extent of overlap between ERIC strategies and BCTs. Third, three implementation scientists independently rated their level of agreement with the categorisation and BCT coding. Finally, discrepancies were settled through online consensus discussions. Additional patterns of complementarity between ERIC strategies and BCTs were labelled thematically. Descriptive statistics summarise the frequency of coded BCTs and the number of strategies mapped to each of the categories of the typology. RESULTS: Across the 73 strategies, 41/93 BCTs (44%) were coded, with \u27restructuring the social environment\u27 as the most frequently coded (n=18 strategies, 25%). There was direct overlap between one strategy (change physical structure and equipment) and one BCT (\u27restructuring physical environment\u27). Most strategy descriptions (n=64) had BCTs that were clearly indicated (n=18), and others where BCTs were probable but not explicitly described (n=31) or indicated multiple types of overlap (n=15). For some strategies, the presence of additional BCTs was dependent on the form of delivery. Some strategies served as examples of broad BCTs operationalised for implementation. For eight strategies, there were no BCTs indicated, or they did not appear to focus on changing behaviour. These strategies reflected preparatory stages and targeted collective cognition at the system level rather than behaviour change at the service delivery level. CONCLUSIONS: This study demonstrates how the ERIC compilation and BCT taxonomy can be integrated to specify active ingredients, providing an opportunity to better understand mechanisms of action. Our results highlight complementarity rather than redundancy. More efforts to integrate these or other taxonomies will aid strategy developers and build links between existing silos in implementation science

    Baseline incidence of adverse birth outcomes and infant influenza and pertussis hospitalisations prior to the introduction of influenza and pertussis vaccination in pregnancy: a data linkage study of 78 382 mother-infant pairs, Northern Territory, Australia, 1994-2015

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    We conducted probabilistic data linkage of three population datasets for the Northern Territory (NT), Australia, to describe the incidence of preterm births, stillbirths, low birthweight and small for gestational age (SGA) per 1000 NT births; and influenza and pertussis hospitalisations per 1 00 000 NT births in infants <7 months of age, in a pre-maternal vaccination era. The Perinatal Trends dataset (1994–2014) formed the cohort of 78 382 births. Aboriginal mother–infant pairs (37%) had disproportionately higher average annual rates (AR) for all adverse birth outcomes compared to their non-Aboriginal counterparts; rate ratios: preterm births 2.2 (AR 142.4 vs. 64.7); stillbirths 2.3 (AR 10.8 vs. 4.6); low birthweight 2.9 (AR 54 vs. 19); and SGA 1.7 (AR 187 vs. 111). Hospitalisation (2000–2015) and Immunisation Register datasets (1994–2015), showed that influenza hospitalisations (n = 53) and rates were 42.3 times higher in Aboriginal infants (AR 254 vs. 6); and that pertussis hospitalisations (n = 37) were 7.1 times higher in Aboriginal infants (AR 142.5 vs. 20.2) compared to non-Aboriginal infants. These baseline data are essential to assess the safety and effectiveness of influenza and pertussis vaccinations in pregnant women from the NT. Remote living Aboriginal women and infants stand to benefit the most from these vaccines.This study was funded by a National Health and Medical Research Council (NHMRC) Project Grant (APP1091491). LMc was supported by an Australian Postgraduate Award scholarship provided by Charles Darwin University of the Northern Territory and an Enhanced Living scholarship provided by Menzies as part of the Doctor of Philosophy (PhD) program. TS holds a Career Development Fellowship from the NHMRC (GNT 1111657). MJB was supported by an NHMRC Early Career Fellowship (GNT1088733)

    Normative Alethic Pluralism

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    Some philosophers have argued that truth is a norm of judgement and have provided a variety of formulations of this general thesis. In this paper, I shall side with these philosophers and assume that truth is a norm of judgement. What I am primarily interested in here are two core questions concerning the judgement-truth norm: (i) what are the normative relationships between truth and judgement? And (ii) do these relationships vary or are they constant? I argue for a pluralist picture—what I call Normative Alethic Pluralism (NAP)—according to which (i) there is more than one correct judgement-truth norm and (ii) the normative relationships between truth and judgement vary in relation to the subject matter of the judgement. By means of a comparative analysis of disagreement in three areas of the evaluative domain—refined aesthetics, basic taste and morality—I show that there is an important variability in the normative significance of disagreement—I call this the variability conjecture. By presenting a variation of Lynch’s scope problem for alethic monism, I argue that a monistic approach to the normative function of truth is unable to vindicate the conjecture. I then argue that normative alethic pluralism provides us with a promising model to account for it

    A study of blood contamination of Siqveland matrix bands

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    AIMS To use a sensitive forensic test to measure blood contamination of used Siqveland matrix bands following routine cleaning and sterilisation procedures in general dental practice. MATERIALS AND METHODS: Sixteen general dental practices in the West of Scotland participated. Details of instrument cleaning procedures were recorded for each practice. A total of 133 Siqveland matrix bands were recovered following cleaning and sterilisation and were examined for residual blood contamination by the Kastle-Meyer test, a well-recognised forensic technique. RESULTS: Ultrasonic baths were used for the cleaning of 62 (47%) bands and retainers and the remainder (53%) were hand scrubbed prior to autoclaving. Overall, 21% of the matrix bands and 19% of the retainers gave a positive Kastle-Meyer test, indicative of residual blood contamination, following cleaning and sterilisation. In relation to cleaning method, 34% of hand-scrubbed bands and 32% of hand-scrubbed retainers were positive for residual blood by the Kastle-Meyer test compared with 6% and 3% respectively of ultrasonically cleaned bands and retainers (P less than 0.001). CONCLUSIONS: If Siqveland matrix bands are re-processed in the assembled state, then adequate pre-sterilisation cleaning cannot be achieved reliably. Ultrasonic baths are significantly more effective than hand cleaning for these items of equipment
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