25,567 research outputs found

    Thinking and acting both locally and globally: new issues for school development planning

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    Managing multiple morbidity in mid-life: a qualitative study of attitudes to drug use

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    OBJECTIVE: To examine attitudes towards drug use among middle aged respondents with high levels of chronic morbidity. DESIGN: Qualitative study with detailed interviews. SETTING: West of Scotland. PARTICIPANTS: 23 men and women aged about 50 years with four or more chronic illnesses. MAIN OUTCOME MEASURE: Participants' feelings about long term use of drugs to manage chronic multiple morbidity. RESULTS: Drugs occupied a central place in the way people managed their comorbidities. Respondents expressed an aversion to taking drugs, despite acknowledging that they depended on drugs to live as "normal" a life as possible. Respondents expressed ambivalence to their drugs in various ways. Firstly, they adopted both regular and more flexible regimens and might adhere to a regular regimen in treating one condition (such as hypertension) while adopting a flexible regimen in relation to others, in response to their experience of symptoms or varying demands of their daily life. Secondly, they expressed reluctance to take drugs, but an inability to be free of them. Thirdly, drugs both facilitated performance of social roles and served as evidence of an inability to perform such roles. CONCLUSIONS: Insight into the considerable tension experienced by people managing complex drug regimens to manage multiple chronic illness may help medical carers to support self care practices among patients and to optimise concordance in their use of prescribed drugs

    Mechanistic and Correlative Models of Ecological Niches

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    The suite of factors that drives where and under what conditions a species occurs has become the focus of intense research interest. Three general categories of methods have emerged by which researchers address questions in this area: mechanistic models of species’ requirements in terms of environmental conditions that are based on first principles of biophysics and physiology, correlational models based on environmental associations derived from analyses of geographic occurrences of species, and process-based simulations that estimate occupied distributional areas and associated environments from assumptions about niche dimensions and dispersal abilities. We review strengths and weaknesses of these sets of approaches, and identify significant advantages and disadvantages of each. Rather than identifying one or the other as ‘better,’ we suggest that researchers take great care to use the method best-suited to each specific research question, and be conscious of the weaknesses of any method, such that inappropriate interpretations are avoided

    Characterizing the uncertainty in holddown post load measurements

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    In order to understand unexpectedly erratic load measurements in the launch-pad supports for the space shuttle, the sensitivities of the load cells in the supports were analyzed using simple probabilistic techniques. NASA engineers use the loads in the shuttle's supports to calculate critical stresses in the shuttle vehicle just before lift-off. The support loads are measured with 'load cells' which are actually structural components of the mobile launch platform which have been instrumented with strain gauges. Although these load cells adequately measure vertical loads, the horizontal load measurements have been erratic. The load measurements were simulated in this study using Monte Carlo simulation procedures. The simulation studies showed that the support loads are sensitive to small deviations in strain and calibration. In their current configuration, the load cells will not measure loads with sufficient accuracy to reliably calculate stresses in the shuttle vehicle. A simplified model of the holddown post (HDP) load measurement system was used to study the effect on load measurement accuracy for several factors, including load point deviations, gauge heights, and HDP geometry

    Hidden supersymmetry of domain walls and cosmologies

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    We show that all domain-wall solutions of gravity coupled to scalar fields for which the worldvolume geometry is Minkowski or anti-de Sitter admit Killing spinors, and satisfy corresponding first-order equations involving a superpotential determined by the solution. By analytic continuation, all flat or closed FLRW cosmologies are shown to satisfy similar first-order equations arising from the existence of ``pseudo-Killing'' spinors.Comment: 4 pages, v2:minor improvements, refs added, version to appear in PR

    Integration of ground and on-board system for terminal count

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    The development of an integrated ground and onboard system for Space Shuttle terminal count management is discussed. The criteria considered in designing this system are outlined. Examples of problems encountered in the process of maturing the design are presented

    Massive Gravity in Three Dimensions

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    A particular higher-derivative extension of the Einstein-Hilbert action in three spacetime dimensions is shown to be equivalent at the linearized level to the (unitary) Pauli-Fierz action for a massive spin-2 field. A more general model, which also includes `topologically-massive' gravity as a special case, propagates the two spin 2 helicity states with different masses. We discuss the extension to massive N{\cal N}-extended supergravity, and we present a `cosmological' extension that admits an anti-de Sitter vacuum.Comment: Minor corrections plus a further correction to discussion of supersymmetry in adS vacua, Version to be publishe

    Gravitons in Flatland

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    We review some features of three-dimensional (3D) massive gravity theories. In particular, we stress the role of the Schouten tensor, explore an analogy with Lovelock gravity and discuss renormalizabilty.Comment: 11 pages, Contribution to proceedings of the workshop {\it Cosmology, the Quantum Vacuum and Zeta Functions} in celebration of the 60th birthday of Emilio Elizalde; Barcelona, 8-10 March, 2010. Additional references in v

    More on Massive 3D Gravity

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    We explore the space of static solutions of the recently discovered three-dimensional `New Massive Gravity' (NMG), allowing for either sign of the Einstein-Hilbert term and a cosmological term parametrized by a dimensionless constant λ\lambda. For λ=1\lambda=-1 we find black hole solutions asymptotic (but not isometric) to the unique (anti) de Sitter vacuum, including extremal black holes that interpolate between this vacuum and (a)dS2×S1_2 \times S^1. We also investigate unitarity of linearized NMG in (a)dS vacua. We find unitary theories for some dS vacua, but (bulk) unitarity in adS implies negative central charge of the dual CFT, except for λ=3\lambda=3 where the central charge vanishes and the bulk gravitons are replaced by `massive photons'. A similar phenomenon is found in the massless limit of NMG, for which the linearized equations become equivalent to Maxwell's equations.Comment: 25 pages, 4 figures; v2: minor improvements and extensions, references added; v3: version to appear in PR
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