1,846 research outputs found

    The impact of culturally competent diabetes care interventions for improving diabetes-related outcomes in ethnic minority groups : a systematic review

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    Aim  To examine the evidence on culturally competent interventions tailored to the needs of people with diabetes from ethnic minority groups. Methods  MEDLINE (NHS Evidence), CINAHL and reference lists of retrieved papers were searched from inception to September 2011; two National Health Service specialist libraries were also searched. Google, Cochrane and DARE databases were interrogated and experts consulted. Studies were included if they reported primary research on the impact of culturally competent interventions on outcome measures of any ethnic minority group with diabetes. Paper selection and appraisal were conducted independently by two reviewers. The heterogeneity of the studies required narrative analysis. A novel culturally competent assessment tool was used to systematically assess the cultural competency of each intervention. Results  Three hundred and twenty papers were retrieved and 11 included. Study designs varied with a diverse range of service providers. Of the interventions, 64% were found to be highly culturally competent (scoring 90–100%) and 36% moderately culturally competent (70–89%). Data were collected from 2616 participants on 22 patient-reported outcome measures. A consistent finding from 10 of the studies was that any structured intervention, tailored to ethnic minority groups by integrating elements of culture, language, religion and health literacy skills, produced a positive impact on a range of patient-important outcomes. Conclusions  Benefits in using culturally competent interventions with ethnic minority groups with diabetes were identified. The majority of interventions described as culturally competent were confirmed as so, when assessed using the culturally competent assessment tool. Further good quality research is required to determine effectiveness and cost-effectiveness of culturally competent interventions to influence diabetes service commissioners

    On time and the quantum-to-classical transition in Jordan-Brans-Dicke quantum gravity

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    Any quantum theory of gravity which treats the gravitational constant as a dynamical variable has to address the issue of superpositions of states corresponding to different eigenvalues. We show how the unobservability of such superpositions can be explained through the interaction with other gravitational degrees of freedom (decoherence). The formal framework is canonically quantized Jordan-Brans-Dicke theory. We discuss the concepts of intrinsic time and semiclassical time as well as the possibility of tunneling into regions corresponding to a negative gravitational constant. We calculate the reduced density matrix of the Jordan-Brans-Dicke field and show that the off-diagonal elements can be sufficiently suppressed to be consistent with experiments. The possible relevance of this mechanism for structure formation in extended inflation is briefly discussed.Comment: 10 pages, Latex, ZU-TH 15/93, BUTP-93/1

    Arrow of time in a recollapsing quantum universe

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    We show that the Wheeler-DeWitt equation with a consistent boundary condition is only compatible with an arrow of time that formally reverses in a recollapsing universe. Consistency of these opposite arrows is facilitated by quantum effects in the region of the classical turning point. Since gravitational time dilation diverges at horizons, collapsing matter must then start re-expanding ``anticausally" (controlled by the reversed arrow) before horizons or singularities can form. We also discuss the meaning of the time-asymmetric expression used in the definition of ``consistent histories". We finally emphasize that there is no mass inflation nor any information loss paradox in this scenario.Comment: Many conceptual clarifications include

    Quantum Theory and Time Asymmetry

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    The relation between quantum measurement and thermodynamically irreversible processes is investigated. The reduction of the state vector is fundamentally asymmetric in time and shows an observer-relatedness which may explain the double interpretation of the state vector as a representation of physical states as well as of information about them. The concept of relevance being used in all statistical theories of irreversible thermodynamics is shown to be based on the same observer-relatedness. Quantum theories of irreversible processes implicitly use an objectivized process of state vector reduction. The conditions for the reduction are discussed, and I speculate that the final (subjective) observer system might even be carried by a spacetime point.Comment: Latex version of a paper published in 1979 (with minor revisions), 18 page

    A Systematic Analysis of Supernova Light in Gamma-Ray Burst Afterglows

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    We systematically reanalyzed all Gamma-Ray Burst (GRB) afterglow data published through the end of 2002, in an attempt to detect the predicted supernova light component and to gain statistical insight on its phenomenological properties. We fit the observed photometric light curves as the sum of an afterglow, an underlying host galaxy, and a supernova component. The latter is modeled using published multi-color light curves of SN 1998bw as a template. The total sample of afterglows with established redshifts contains 21 bursts (GRB 970228 - GRB 021211). For nine of these GRBs a weak supernova excess (scaled to SN 1998bw) was found, what makes this to one of the first samples of high-z core collapse supernovae. Among this sample are all bursts with redshifts less than ~0.7. These results strongly support the notion that in fact all afterglows of long-duration GRBs contain light from an associated supernova. A statistics of the physical parameters of these GRB-supernovae shows that SN 1998bw was at the bright end of its class, while it was not special with respect to its light curve shape. Finally, we have searched for a potential correlation of the supernova luminosities with the properties of the corresponding bursts and optical afterglows, but we have not found such a relation.Comment: 25 pages, 7 figures, accepted by ApJ; revised, shortened and updated compared to version 1; Title slightly changed; all figures showing individual afterglow light curves removed, as advised by the referee; conclusions unchange

    Classical and quantum LTB model for the non-marginal case

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    We extend the classical and quantum treatment of the Lemaitre-Tolman-Bondi (LTB) model to the non-marginal case (defined by the fact that the shells of the dust cloud start with a non-vanishing velocity at infinity). We present the classical canonical formalism and address with particular care the boundary terms in the action. We give the general relation between dust time and Killing time. Employing a lattice regularization, we then derive and discuss for particular factor orderings exact solutions to all quantum constraints.Comment: 23 pages, no figures, typos correcte

    Entanglement and the Thermodynamic Arrow of Time

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    We discuss quantum entanglement in the context of the thermodynamic arrow of time. We review the role of correlations in entropy-decreasing events and prove that the occurrence of a transformation between two thermodynamic states constitutes a new type of entanglement witness, one not defined as a separating plane in state space between separable and entangled states, but as a physical process dependent on the local initial properties of the states. Extending work by Partovi, we consider a general entangled multipartite system that allows large reversals of the thermodynamic arrow of time. We describe a hierarchy of arrows that arises from the different correlations allowed in a quantum state and examine these features in the context of Maxwell's Demon. We examine in detail the case of three qubits, and also propose some simple experimental demonstrations possible with small numbers of qubits.Comment: 10 pages with 9 figure

    Quantum cosmology with big-brake singularity

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    We investigate a cosmological model with a big-brake singularity in the future: while the first time derivative of the scale factor goes to zero, its second time derivative tends to minus infinity. Although we also discuss the classical version of the model in some detail, our main interest lies in its quantization. We formulate the Wheeler-DeWitt equation and derive solutions describing wave packets. We show that all such solutions vanish in the region of the classical singularity, a behaviour which we interpret as singularity avoidance. We then discuss the same situation in loop quantum cosmology. While this leads to a different factor ordering, the singularity is there avoided, too.Comment: 24 pages, 7 figures, figures improved, references added, conceptual clarifications include

    Early optical observations of GRBs by the TAROT telescopes: period 2001-2008

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    The TAROT telescopes (Telescopes a Action Rapide pour les Objets Transitoires) are two robotic observatories designed to observe the prompt optical emission counterpart and the early afterglow of gamma ray bursts (GRBs). We present data acquired between 2001 and 2008 and discuss the properties of the optical emission of GRBs, noting various interesting results. The optical emission observed during the prompt GRB phase is rarely very bright: we estimate that 5% to 20% of GRBs exhibit a bright optical flash (R<14) during the prompt gamma-ray emission, and that more than 50% of the GRBs have an optical emission fainter than R=15.5 when the gamma-ray emission is active. We study the apparent optical brightness distribution of GRBs at 1000 s showing that our observations confirm the distribution derived by other groups. The combination of these results with those obtained by other rapid slewing telescopes allows us to better characterize the early optical emission of GRBs and to emphasize the importance of very early multi-wavelength GRB studies for the understanding of the physics of the ejecta.Comment: 13 pages, 2 color figures, 5 b&w figures. Accepted for publication in Astronomical Journa
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