1,746 research outputs found

    Designing dual-plate meteoroid shields: A new analysis

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    Physics governing ultrahigh velocity impacts onto dual-plate meteor armor is discussed. Meteoroid shield design methodologies are considered: failure mechanisms, qualitative features of effective meteoroid shield designs, evaluating/processing meteoroid threat models, and quantitative techniques for optimizing effective meteoroid shield designs. Related investigations are included: use of Kevlar cloth/epoxy panels in meteoroid shields for the Halley's Comet intercept vehicle, mirror exposure dynamics, and evaluation of ion fields produced around the Halley Intercept Mission vehicle by meteoroid impacts

    Disaster warning system: Satellite feasibility and comparison with terrestrial systems. Volume 1: Executive summary

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    The Disaster Warning System (DWS) is a conceptual system which will provide the National Weather Service (NWS) with communication services in the 1980s to help minimize losses caused by natural disasters. The object of this study is a comparative analysis between a terrestrial DWS and a satellite DWS. Baseline systems satisfying the NOAA requirements were synthesized in sufficient detail so that a comparison could be made in terms of performance and cost. The cost of both baseline systems is dominated by the disaster warning and spotter reporting functions. An effort was undertaken to reduce system cost through lower-capacity alternative systems generated by modifying the baseline systems. By reducing the number of required channels and modifying the spotter reporting techniques, alternative satellite systems were synthesized. A terrestrial alternative with the coverage reduced to an estimated 95 percent of the population was considered

    Practice-based Reflection: Considerations for Re-engineering Secondary Healthcare in New Zealand

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    Re-engineering is the "buzz" word of the nineties. Re-engineering has been successful in industry. Now the principals of re-engineering are being applied to healthcare. Considerations for re-engineering secondary healthcare in New Zealand will be examined in this literature review, which is divided into two sections. The first section provides the aims of the literature review, my background interest and knowledge of the topic, it's relevance to nursing practice, plans for addressing the literature review, and proposed sources of information. Section two illustrates the learning contract to manage the task of conducting the literature review. It identifies timelines for managing the project and agreed arrangements for communication with my mentor. Finally, a report will address my progress in relation to my learning contract articulating insights gained and hopes and dreams for successfully incorporating process re-engineering in my area of nursing and midwifery practice in the future

    Neonatal hearing screening: modelling cost and effectiveness of hospital- and community-based screening

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    This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Children with congenital hearing impairment benefit from early detection and management of their hearing loss. These and related considerations led to the recommendation of universal newborn hearing screening. In 2001 the first phase of a national Newborn Hearing Screening Programme (NHSP) was implemented in England. Objective of this study was to assess costs and effectiveness for hospital and community-based newborn hearing screening systems in England based on data from this first phase with regard to the effects of alterations to parameter values. METHODS: DESIGN: Clinical effectiveness analysis using a Markov Model. OUTCOME MEASURE: quality weighted detected child months (QCM). RESULTS: Both hospital and community programmes yielded 794 QCM at the age of 6 months with total costs of 3,690,000 pound sterling per 100,000 screened children in hospital and 3,340,000 pound sterling in community. Simulated costs would be lower in hospital in 48% of the trials. Any statistically significant difference between hospital and community in prevalence, test sensitivity, test specificity and costs would result in significant differences in cost-effectiveness between hospital and community. CONCLUSION: This modelling exercise informs decision makers by a quantitative projection of available data and the explicit and transparent statements about assumptions and the degree of uncertainty. Further evaluation of the cost-effectiveness should focus on the potential differences in test parameters and prevalence in these two settings.This work was undertaken by the Evaluation Team for the Implementation Pilot of Newborn Hearing Screening in England which received funding from the Department of Health

    Cochlear SGN neurons elevate pain thresholds in response to music.

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    The C-tactile (CLTM) peripheral nervous system is involved in social bonding in primates and humans through its capacity to trigger the brain’s endorphin system. Since the mammalian cochlea has an unusually high density of similar neurons (type-II spiral ganglion neurons, SGNs), we hypothesise that their function may have been exploited for social bonding by co-opting head movements in response to music and other rhythmic movements of the head in social contexts. Music provides one of many cultural behavioural mechanisms for ‘virtual grooming’ in that it is used to trigger the endorphin system with many people simultaneously so as to bond both dyadic relationships and large groups. Changes in pain threshold across an activity are a convenient proxy assay for endorphin uptake in the brain, and we use this, in two experiments, to show that pain thresholds are higher when nodding the head than when sitting still

    An XQuery-based Model Transformation Language

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    In this paper we propose a framework for model transformation in XQuery. Our proposal aims to provide the elements for using XQuery as a transformation language. With this aim, our framework provides a mechanism for automatically obtaining an XQuery library for a given meta-model. Meta-models are defined as XML schemas, and the XQuery library serves to query and create elements of an XML Schema. Transformations abstract from XML representation, in the sense of, elements from meta-models are encapsulated by XQuery functions. We have also studied how to use our framework for model validation. Source and target models and transformations are validated by considering constraints. The framework has been tested with a case study of transformation in UML, where the XML-based representation of models is achieved by the standardized language XMI

    3D pic simulations of collisionless shocks at lunar magnetic anomalies and their role in forming lunar swirls

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    The authors would like to thank the Science and Technology Facilities Council for fundamental physics and computing resources that were provided by funding from STFC’s Scientific Computing Department, and would like to thank the European Research Council (ERC 2010 AdG Grant 267841) and FCT (Portugal) grants SFRH/BD/75558/2010 for support.Investigation of the lunar crustal magnetic anomalies offers a comprehensive long-term data set of observations of small-scale magnetic fields and their interaction with the solar wind. In this paper a review of the observations of lunar mini-magnetospheres is compared quantifiably with theoretical kinetic-scale plasma physics and 3D particle-in-cell simulations. The aim of this paper is to provide a complete picture of all the aspects of the phenomena and to show how the observations from all the different and international missions interrelate. The analysis shows that the simulations are consistent with the formation of miniature (smaller than the ion Larmor orbit) collisionless shocks and miniature magnetospheric cavities, which has not been demonstrated previously. The simulations reproduce the finesse and form of the differential proton patterns that are believed to be responsible for the creation of both the "lunar swirls" and "dark lanes." Using a mature plasma physics code like OSIRIS allows us, for the first time, to make a side-by-side comparison between model and space observations. This is shown for all of the key plasma parameters observed to date by spacecraft, including the spectral imaging data of the lunar swirls. The analysis of miniature magnetic structures offers insight into multi-scale mechanisms and kinetic-scale aspects of planetary magnetospheres.Publisher PDFPeer reviewe
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