76 research outputs found

    Equilibrium configurations of two charged masses in General Relativity

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    An asymptotically flat static solution of Einstein-Maxwell equations which describes the field of two non-extreme Reissner - Nordstr\"om sources in equilibrium is presented. It is expressed in terms of physical parameters of the sources (their masses, charges and separating distance). Very simple analytical forms were found for the solution as well as for the equilibrium condition which guarantees the absence of any struts on the symmetry axis. This condition shows that the equilibrium is not possible for two black holes or for two naked singularities. However, in the case when one of the sources is a black hole and another one is a naked singularity, the equilibrium is possible at some distance separating the sources. It is interesting that for appropriately chosen parameters even a Schwarzschild black hole together with a naked singularity can be "suspended" freely in the superposition of their fields.Comment: 4 pages; accepted for publication in Phys. Rev.

    Intergenerational Community-Based Research and Creative Practice: Promoting Environmental Sustainability in Jinja, Uganda

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    This article critically reflects on the methodological approach developed for a recent project based in Jinja, Uganda, that sought to generate new forms of environmental knowledge and action utilizing diverse forms of creative intergenerational practice embedded within a broader framework of community-based participatory research. This approach provided new opportunities for intergenerational dialogue in Jinja, generated increased civic environmental engagement, and resulted in a participant-led campaign to share knowledge regarding sustainable biomass consumption. We term this approach intergenerational community-based research and creative practice. We discuss the advantages of this model while also reflecting throughout on the challenges of the approach

    Effect of the 3K background radiation on ultrahigh energy cosmic rays

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    In this work we re-examine the opacity of the cosmic background radiation to the propagation of extremely high energy cosmic rays. We use the continuous energy loss approximation to provide spectral modification factors for several hypothesized cosmic ray sources. Earlier problems with this approximation are resolved including the effects of resonances other than the Δ\Delta.Comment: 13 pages revtex, 3 figures. To appear in Phys. Rev.

    Attitudes to long-term care in multiple sclerosis.

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    At a recent conference workshop, a group of specialist nurses examined their attitudes towards individuals with multiple sclerosis moving into long-term care. This article summarises how the group members examined their attitudes, the literature reviewed and what was learnt by sharing experiences. It also suggests how nurses could promote positive attitudes towards, and ease, the transition of patients into long-term residential care
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