25,125 research outputs found

    ∗\ast-SDYM fields and heavenly spaces: II. Reductions of the ∗\ast-SDYM system

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    Reductions of self-dual Yang-Mills (SDYM) system for ∗\ast-bracket Lie algebra to the Husain-Park (HP) heavenly equation and to sl(N,{\boldmath{C}) SDYM equation are given. An example of a sequence of su(N)su(N) chiral fields (N≥2N\geq 2) tending for N→∞N\to\infty to a curved heavenly space is found.Comment: 18 page

    Exploring knowledge exchange: a useful framework for practice and policy

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    Knowledge translation is underpinned by a dynamic and social knowledge exchange process but there are few descriptions of how this unfolds in practice settings. This has hampered attempts to produce realistic and useful models to help policymakers and researchers understand how knowledge exchange works. This paper reports the results of research which investigated the nature of knowledge exchange. We aimed to understand whether dynamic and fluid definitions of knowledge exchange are valid and to produce a realistic, descriptive framework of knowledge exchange. Our research was informed by a realist approach. We embedded a knowledge broker within three service delivery teams across a large mental health organisation, each of whom was grappling with specific challenges. The knowledge broker participated in the team's problem-solving process and collected observational fieldnotes. We also interviewed the team members. Observational and interview data were analysed quantitatively and qualitatively in order to determine and describe the nature of the knowledge exchange process in more detail. This enabled us to refine our conceptual framework of knowledge exchange. We found that knowledge exchange can be understood as a dynamic and fluid process which incorporates distinct forms of knowledge from multiple sources. Quantitative analysis illustrated that five broadly-defined components of knowledge exchange (problem, context, knowledge, activities, use) can all be in play at any one time and do not occur in a set order. Qualitative analysis revealed a number of distinct themes which better described the nature of knowledge exchange. By shedding light on the nature of knowledge exchange, our findings problematise some of the linear, technicist approaches to knowledge translation. The revised model of knowledge exchange which we propose here could therefore help to reorient thinking about knowledge exchange and act as a starting point for further exploration and evaluation of the knowledge exchange process

    On a low energy bound in a class of chiral field theories with solitons

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    A low energy bound in a class of chiral solitonic field theories related the infrared physics of the SU(N) Yang-Mills theory is established.Comment: Plain Latex, 8 pages, no figure

    Type I singularities and the Phantom Menace

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    We consider the future dynamics of a transient phantom dominated phase of the universe in LQC and in the RS braneworld, which both have a non-standard Friedmann equation. We find that for a certain class of potentials, the Hubble parameter oscillates with simple harmonic motion in the LQC case and therefore avoids any future singularity. For more general potentials we find that damping effects eventually lead to the Hubble parameter becoming constant. On the other hand in the braneworld case we find that although the type I singularity can be avoided, the scale factor still diverges at late times.Comment: More references added. Final PRD versio

    Numerical Investigation of Monopole Chains

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    We present numerical results for chains of SU(2) BPS monopoles constructed from Nahm data. The long chain limit reveals an asymmetric behavior transverse to the periodic direction, with the asymmetry becoming more pronounced at shorter separations. This analysis is motivated by a search for semiclassical finite temperature instantons in the 3D SU(2) Georgi-Glashow model, but it appears that in the periodic limit the instanton chains either have logarithmically divergent action or wash themselves out.Comment: 14 pages, 6 figures; v2 minor changes, published versio

    An industry-level analysis of potential intangible and economic impacts affecting Australian pork producers during an emergency animal disease control program

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    Emerging and transboundary diseases have been responsible for dramatic impacts on human health, the economy, trade, animal health and biodiversity in Australia and around the world. The Australian pig industry’s health status provides it with a competitive advantage. Freedom from major transboundary diseases – such as foot-and-mouth disease and classical swine fever – secures access to international markets and enables producers to invest in their businesses free from the complication of major disease incursions, ensures the industry’s future sustainability and allows it to meet community standards for food production. Planning for a disease response is driven by many factors. Among these factors, the cost of the response is often the single most important driving factor. However, cost involves more than the actual financial cost of the response. It involves a number of intangible elements and the views of a diverse range of stakeholders. For example, human health, environmental and sociological consequences need to be considered. Currently, a unifying framework for such decision-making is unavailable. Application of a newly developed framework to several diseases that concern the Australian pig industry will facilitate dialogue on what is the best response to minimize the impact of incursions of such diseases. This novel framework for economic analysis of animal health emergencies incorporates risk assessment, tangible and intangible elements and a value-added cost-benefit analysis. These case studies assess the comparability, applicability and accountability of different response actions through producer perspectives. An example of the application of this framework for a disease which threatens the Australian pig industry will be presented

    Resummed Quantum Gravity

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    We present the current status of the a new approach to quantum general relativity based on the exact resummation of its perturbative series as that series was formulated by Feynman. We show that the resummed theory is UV finite and we present some phenomenological applications as well.Comment: 4 pages, 1 figure; presented at ICHEP0

    Multiple Gluon Effects in q+qˉ→t+tˉ+Xq+\bar q\to t+\bar t + X at FNAL Energies: Semi-Analytical Results

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    We apply our Yennie-Frautschi-Suura exponentiated cross section formulas for the parton processes q + {^(} \bar q {^)}{^\prime} \ra q{^\prime}{^\prime} + {^(} \bar q {^)}{^\prime}{^\prime}{^\prime} + n(G) to the process q + \bar q \ra t + \bar t + n(G) at FNAL energies, where G is a QCD gluon. We use semi-analytical methods to compute the ratio rexp=σexp/σBr_{exp}=\sigma_{exp}/\sigma_B, where σexp\sigma_{exp} is our soft gluon YFS exponentiated cross section and σB\sigma_B is the Born cross section. For mt=0.176(0.199)m_t= 0.176(0.199)TeV, we get rexp=1.65(1.48)r_{exp}=1.65(1.48), respectively, for q=uq=u for example. These results are not inconsistent with the recent observations by CDF and D0.Comment: 6 pages, latex replaces postscript at archiver's reques
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