3,989 research outputs found

    Skyrmions from calorons

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    We derive a one-parameter family of gauged Skyrme models from Yang-Mills theory on S1×R3S^1\times\mathbb{R}^3, in which skyrmions are well-approximated by calorons and monopoles. In particular we study the spherically symmetric solutions to the model with two distinct classes of boundary conditions, and compare them to calorons and monopoles. Calorons interpolate between instantons and monopoles in certain limits, and we observe similar behaviour in the constructed gauged Skyrme model in the weak and strong coupling limits. This comparison of calorons, monopoles, and skyrmions may be a way to further understand the apparent relationships between skyrmions and monopoles on R3\mathbb{R}^3.Comment: References added & minor corrections. Matches journal version. 39 pages, 12 figure

    Linking Gun Availability to Youth Gun Violence

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    Fault detection, identification and accommodation techniques for unmanned airborne vehicles

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    Unmanned Airborne Vehicles (UAV) are assuming prominent roles in both the commercial and military aerospace industries. The promise of reduced costs and reduced risk to human life is one of their major attractions, however these low-cost systems are yet to gain acceptance as a safe alternate to manned solutions. The absence of a thinking, observing, reacting and decision making pilot reduces the UAVs capability of managing adverse situations such as faults and failures. This paper presents a review of techniques that can be used to track the system health onboard a UAV. The review is based on a year long literature review aimed at identifying approaches suitable for combating the low reliability and high attrition rates of today’s UAV. This research primarily focuses on real-time, onboard implementations for generating accurate estimations of aircraft health for fault accommodation and mission management (change of mission objectives due to deterioration in aircraft health). The major task of such systems is the process of detection, identification and accommodation of faults and failures (FDIA). A number of approaches exist, of which model-based techniques show particular promise. Model-based approaches use analytical redundancy to generate residuals for the aircraft parameters that can be used to indicate the occurrence of a fault or failure. Actions such as switching between redundant components or modifying control laws can then be taken to accommodate the fault. The paper further describes recent work in evaluating neural-network approaches to sensor failure detection and identification (SFDI). The results of simulations with a variety of sensor failures, based on a Matlab non-linear aircraft model are presented and discussed. Suggestions for improvements are made based on the limitations of this neural network approach with the aim of including a broader range of failures, while still maintaining an accurate model in the presence of these failures

    Stories of opportunity, challenges, and hardship in Irish men aged 65 and over

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    Introduction: There is a long and complex history of migration from Ireland to Britain. However both the impact of migration and dislocation, and the reasons for leaving Ireland mean that this population in Britain require a specific focus as a group in terms of mental health and wellbeing. The aging male population in particular experience a greater burden of socioeconomic and health issues compared to those born in Britain, and experience higher levels of mental health issues. There is currently a gap in the research in terms of eliciting personal accounts from this population and examining this through a psychological or mental health lens. Methods: Five semi-structured interviews were carried out with older Irish men living in London, recruited through an organisation that supports this population. Interviews were analysed using thematic and performative narrative analysis. Results: Findings suggested that these men storied their experiences in unique ways according to their personal, social, and cultural contexts. The narrative accounts explored demonstrate a focus on stories around work, labour, masculinity, place in the community, bodies and disabilities, and migration and home. The performative analysis applied to the interviews illuminates the multiple and dynamic ways in which participants story their lives and identities. Discussion: These findings were discussed in relation to relevant literature on mental health, general health, and community. The findings were also discussed in terms of their implications for and applications to the field of clinical psychology and the therapeutic encounter in general

    The future of UAS: standards, regulations, and operational experiences [workshop report]

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    This paper presents the outcomes of "The Future of UAS: Standards, Regulations and Operational Experiences" workshop, held on the 7th and 8th of December, 2006 in Brisbane, Queensland, Australia. The goal of the workshop was to identify recent international activities in the Unmanned Airborne Systems (UAS) airspace integration problem. The workshop attracted a broad cross-section of the UAS community, including: airspace and safety regulators, developers, operators and researchers. The three themes of discussion were: progress in the development of standards and regulations, lessons learnt from recent operations, and advances in new technologies. This paper summarises the activities of the workshop and explores the important outcomes and trends as perceived by the authors

    Developing strategic learning alliances: partnerships for the provision of global education and training solutions

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    The paper describes a comprehensive model for the development of strategic alliances between education and corporate sectors, which is required to ensure effective provision of education and training programmes for a global market. Global economic forces, combined with recent advances in information and communication technologies, have provided unprecedented opportunities for education providers to broaden the provision of their programmes both on an international scale and across new sectors. Lifelong learning strategies are becoming increasingly recognized as an essential characteristic of a successful organization and therefore large organizations have shown a preparedness to invest in staff training and development. The demands for lifelong learning span a wide range of training and educational levels from school-level and vocational courses to graduate-level training for senior executive
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