423 research outputs found

    SOME CHANGES REQUIRED TO INCREASE THE PUBLIC'S UTILIZATION OF PREVENTIVE DENTISTRY *

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65250/1/j.1752-7325.1968.tb03923.x.pd

    An experimental study of the behavior of supervisors given high and low power over their subordinates.

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    Thesis (Ph.D.)--Boston University N.B.: page 73 appear to be missing from the physical thesis. We believe that this is a page numbering error on the author's part, and no actual content is missing.An experimental study of the behavior of supervisors given high and low power over their subordinates This study permitted an exploration under specific conditions of the behavior of persons with high power. The definition of power used here was first formulated by Hymovitch, as: the ability of any person in an interpersonal relationship to reward or punish the other person in the relationship in some particular way in some particular situation. Focal points for the theory were two constructs, (1) the power-ratio, within any two person relationship, defined as: the power of one person over a second as compared in some way to the power of the second over the fist, and (2) the maximal-needed power, defined as:a state where an individual higher in the power-ratio perceives that all of his needs, over which the person lower has control, are being satisfied by the person lower in the power-ratio. Theoretical considerations seemed to indicate that persons who varied in distance from the maximal-needed power would accordingly vary in their behavior toward subordinates. An experiment was designed to test formulations about the behavior of persons with high power. In the experimental situation, subjects met in fifteen groups of four and were told they were to work on a problem involving the assessment of persons from autobiographical sketches. They were told that one of them was to be selected on a chance basis as supervisor, the other three would serve as subordinates. They were further instructed that in some of these experiments the supervisor would have high power to recommend rewards for subordinates, while in other experiments he would have low power. In each group, the four subjects were then separated for the remainder of the experiment, and each received instructions that telling them they had high power to recommend rewards for the subordinates; the other two were told they had low power. Each subject then received notes apparently written by each of his subordinates but actually prepared in advance by the experimenter. The notes he received were a hostile notes, a praise note and a neutral note, each coupled with equally inaccurate evaluations of the characters described in the autographical sketches. The supervisor (i.e., each subject) according to instructions, compared these evaluations with "correct" evaluations, and then answered each supposed subordinate. After the experiment, each subject was asked through a questionaire to recommend each subordinate for financial rewards to which he felt the subordinate was entitled. The size of the reward varied between zero and ten dollars. Several weeks after the experimental session, subjects were requested to fill out an autocratic-democratic ideology scale. The data for the experiment were tabulated from (1) a codification of the analysis of notes communicated by all subjects and (2) an analysis of the questionaire. [Truncated

    Robertson-Walker fluid sources endowed with rotation characterised by quadratic terms in angular velocity parameter

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    Einstein's equations for a Robertson-Walker fluid source endowed with rotation Einstein's equations for a Robertson-Walker fluid source endowed with rotation are presented upto and including quadratic terms in angular velocity parameter. A family of analytic solutions are obtained for the case in which the source angular velocity is purely time-dependent. A subclass of solutions is presented which merge smoothly to homogeneous rotating and non-rotating central sources. The particular solution for dust endowed with rotation is presented. In all cases explicit expressions, depending sinusoidally on polar angle, are given for the density and internal supporting pressure of the rotating source. In addition to the non-zero axial velocity of the fluid particles it is shown that there is also a radial component of velocity which vanishes only at the poles. The velocity four-vector has a zero component between poles

    Slowly, rotating non-stationary, fluid solutions of Einstein's equations and their match to Kerr empty space-time

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    A general class of solutions of Einstein's equation for a slowly rotating fluid source, with supporting internal pressure, is matched using Lichnerowicz junction conditions, to the Kerr metric up to and including first order terms in angular speed parameter. It is shown that the match applies to any previously known non-rotating fluid source made to rotate slowly for which a zero pressure boundary surface exists. The method is applied to the dust source of Robertson-Walker and in outline to an interior solution due to McVittie describing gravitational collapse. The applicability of the method to additional examples is transparent. The differential angular velocity of the rotating systems is determined and the induced rotation of local inertial frame is exhibited

    Reconstruction of Black Hole Metric Perturbations from Weyl Curvature

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    Perturbation theory of rotating black holes is usually described in terms of Weyl scalars ψ4\psi_4 and ψ0\psi_0, which each satisfy Teukolsky's complex master wave equation and respectively represent outgoing and ingoing radiation. On the other hand metric perturbations of a Kerr hole can be described in terms of (Hertz-like) potentials Κ\Psi in outgoing or ingoing {\it radiation gauges}. In this paper we relate these potentials to what one actually computes in perturbation theory, i.e ψ4\psi_4 and ψ0\psi_0. We explicitly construct these relations in the nonrotating limit, preparatory to devising a corresponding approach for building up the perturbed spacetime of a rotating black hole. We discuss the application of our procedure to second order perturbation theory and to the study of radiation reaction effects for a particle orbiting a massive black hole.Comment: 6 Pages, Revtex

    Kerr-AdS and its Near-horizon Geometry: Perturbations and the Kerr/CFT Correspondence

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    We investigate linear perturbations of spin-s fields in the Kerr-AdS black hole and in its near-horizon geometry (NHEK-AdS), using the Teukolsky master equation and the Hertz potential. In the NHEK-AdS geometry we solve the associated angular equation numerically and the radial equation exactly. Having these explicit solutions at hand, we search for linear mode instabilities. We do not find any (non-)axisymmetric instabilities with outgoing boundary conditions. This is in agreement with a recent conjecture relating the linearized stability properties of the full geometry with those of its near-horizon geometry. Moreover, we find that the asymptotic behaviour of the metric perturbations in NHEK-AdS violates the fall-off conditions imposed in the formulation of the Kerr/CFT correspondence (the only exception being the axisymmetric sector of perturbations).Comment: 26 pages. 4 figures. v2: references added. matches published versio

    The SPORTSMART study: a pilot randomised controlled trial of sexually transmitted infection screening interventions targeting men in football club settings

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    Background: Uptake of chlamydia screening by men in England has been substantially lower than by women. Non-traditional settings such as sports clubs offer opportunities to widen access. Involving people who are not medically trained to promote screening could optimise acceptability. Methods: We developed two interventions to explore the acceptability and feasibility of urine-based sexually transmitted infection (STI) screening interventions targeting men in football clubs. We tested these interventions in a pilot cluster randomised control trial. Six clubs were randomly allocated, two to each of three trial arms: team captain-led and poster STI screening promotion; sexual health adviser-led and poster STI screening promotion; and poster-only STI screening promotion (control/comparator). Primary outcome was test uptake. Results: Across the three arms, 153 men participated in the trial and 90 accepted the offer of screening (59%, 95% CI 35% to 79%). Acceptance rates were broadly comparable across the arms: captain-led: 28/56 (50%); health professional-led: 31/46 (67%); and control: 31/51 (61%). However, rates varied appreciably by club, precluding formal comparison of arms. No infections were identified. Process evaluation confirmed that interventions were delivered in a standardised way but the control arm was unintentionally ‘enhanced’ by some team captains actively publicising screening events. Conclusions: Compared with other UK-based community screening models, uptake was high but gaining access to clubs was not always easy. Use of sexual health advisers and team captains to promote screening did not appear to confer additional benefit over a poster-promoted approach. Although the interventions show potential, the broader implications of this strategy for UK male STI screening policy require further investigation

    Second order gauge invariant gravitational perturbations of a Kerr black hole

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    We investigate higher than the first order gravitational perturbations in the Newman-Penrose formalism. Equations for the Weyl scalar ψ4,\psi_4, representing outgoing gravitational radiation, can be uncoupled into a single wave equation to any perturbative order. For second order perturbations about a Kerr black hole, we prove the existence of a first and second order gauge (coordinates) and tetrad invariant waveform, ψI\psi_I, by explicit construction. This waveform is formed by the second order piece of ψ4\psi_4 plus a term, quadratic in first order perturbations, chosen to make ψI\psi_I totally invariant and to have the appropriate behavior in an asymptotically flat gauge. ψI\psi_I fulfills a single wave equation of the form TψI=S,{\cal T}\psi_I=S, where T{\cal T} is the same wave operator as for first order perturbations and SS is a source term build up out of (known to this level) first order perturbations. We discuss the issues of imposition of initial data to this equation, computation of the energy and momentum radiated and wave extraction for direct comparison with full numerical approaches to solve Einstein equations.Comment: 19 pages, REVTEX. Some misprints corrected and changes to improve presentation. Version to appear in PR

    Towards a methodology for cluster searching to provide conceptual and contextual "richness" for systematic reviews of complex interventions: case study (CLUSTER)

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    Background Systematic review methodologies can be harnessed to help researchers to understand and explain how complex interventions may work. Typically, when reviewing complex interventions, a review team will seek to understand the theories that underpin an intervention and the specific context for that intervention. A single published report from a research project does not typically contain this required level of detail. A review team may find it more useful to examine a “study cluster”; a group of related papers that explore and explain various features of a single project and thus supply necessary detail relating to theory and/or context. We sought to conduct a preliminary investigation, from a single case study review, of techniques required to identify a cluster of related research reports, to document the yield from such methods, and to outline a systematic methodology for cluster searching. Methods In a systematic review of community engagement we identified a relevant project – the Gay Men’s Task Force. From a single “key pearl citation” we conducted a series of related searches to find contextually or theoretically proximate documents. We followed up Citations, traced Lead authors, identified Unpublished materials, searched Google Scholar, tracked Theories, undertook ancestry searching for Early examples and followed up Related projects (embodied in the CLUSTER mnemonic). Results Our structured, formalised procedure for cluster searching identified useful reports that are not typically identified from topic-based searches on bibliographic databases. Items previously rejected by an initial sift were subsequently found to inform our understanding of underpinning theory (for example Diffusion of Innovations Theory), context or both. Relevant material included book chapters, a Web-based process evaluation, and peer reviewed reports of projects sharing a common ancestry. We used these reports to understand the context for the intervention and to explore explanations for its relative lack of success. Additional data helped us to challenge simplistic assumptions on the homogeneity of the target population. Conclusions A single case study suggests the potential utility of cluster searching, particularly for reviews that depend on an understanding of context, e.g. realist synthesis. The methodology is transparent, explicit and reproducible. There is no reason to believe that cluster searching is not generalizable to other review topics. Further research should examine the contribution of the methodology beyond improved yield, to the final synthesis and interpretation, possibly by utilizing qualitative sensitivity analysis
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