3,571 research outputs found

    Rosenfeld, Bergmann, Dirac and the Invention of Constrained Hamiltonian Dynamics

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    In a paper appearing in Annalen der Physik in 1930 Leon Rosenfeld invented the first procedure for producing Hamiltonian constraints. He displayed and correctly distinguished the vanishing Hamiltonian generator of time evolution, and the vanishing generator of gauge transformations for general relativity with Dirac electron and electrodynamic field sources. Though he did not do so, had he chosen one of his tetrad fields to be normal to his spacetime foliation, he would have anticipated by almost thirty years the general relativisitic Hamiltonian first published by Paul Dirac.Comment: 5 pages, to appear in the Proceedings of the Eleventh Marcel Grossmann Meetin

    Using Co-Production in Interventions to Reduce Health Inequalities: A Qualitative Study of Process and Impact

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    This thesis explores the use and impact of co-production in the development and implementation of interventions to reduce health inequalities. My empirical research focuses on the use of co-production in an intervention designed to reduce inequality in access to antenatal care (the Community REACH intervention). Despite improvements in health, health inequalities remain prevalent worldwide. Co-production has been widely advocated in public health discourse because of its potential to address health inequalities. Co-production involves active participation of individuals and communities in designing, developing, and implementing interventions, services, or initiatives through equal and reciprocal relationships. Despite the promise of co-production, there is a lack of empirical evidence concerning process and impact, specifically in translating theory into practice and identifying factors that influence implementation. This thesis used qualitative research and combined observations and interviews to identify factors that supported or hindered the use of co-production in the Community REACH intervention. The study developed fidelity indicators to assess adherence to co-production principles and practices. Reciprocity, a foundational principle of co-production, was found to be key for successful implementation and facilitated other co-production elements. Collaborative practices were characterised by power imbalances connected to differences in disciplinary practices and insufficient attention dedicated to relationship‐building. This points to the need for a deliberate focus on relational practices to develop reciprocal relations and inclusive environments. Without these it was difficult for the various actors involved to establish shared understanding, negotiate roles, encourage social interactions among participants, and ensure a consistent high-fidelity co-production approach. The study also found that participating in a co-production process created a valuable community resource of volunteers who had strengthened their social networks and developed their capabilities and confidence to access new opportunities. The study also found that those who participated in the co-production process strengthened their social networks, developed their capabilities and their confidence to access new opportunities, and together became a valuable community resource of volunteers. Fidelity indicators developed in this study identify critical factors in the co-production process and potential solutions to avoid or address them, offering a systematic framework that leaves room for creativity in co-production. Future research should develop this set of fidelity indicators further

    A generalized Schroedinger equation for loop quantum cosmology

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    A temporally discrete Schroedinger time evolution equation is proposed for isotropic quantum cosmology coupled to a massless scalar source. The approach employs dynamically determined intrinsic time and produces the correct semiclassical limit.Comment: 5 pages, to appear in the Proceedings of the Eleventh Marcel Grossmann Meetin

    Gauge transformations in the Lagrangian and Hamiltonian formalisms of generally covariant theories

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    We study spacetime diffeomorphisms in Hamiltonian and Lagrangian formalisms of generally covariant systems. We show that the gauge group for such a system is characterized by having generators which are projectable under the Legendre map. The gauge group is found to be much larger than the original group of spacetime diffeomorphisms, since its generators must depend on the lapse function and shift vector of the spacetime metric in a given coordinate patch. Our results are generalizations of earlier results by Salisbury and Sundermeyer. They arise in a natural way from using the requirement of equivalence between Lagrangian and Hamiltonian formulations of the system, and they are new in that the symmetries are realized on the full set of phase space variables. The generators are displayed explicitly and are applied to the relativistic string and to general relativity.Comment: 12 pages, no figures; REVTeX; uses multicol,fancyheadings,eqsecnum; to appear in Phys. Rev.

    "Functional electrical stimulation (FES) impacted on important aspects of my life" - A qualitative exploration of chronic stroke patients' and carers' perceptions of FES in the management of dropped foot.

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    Our purpose was to explore the impact of functional electrical stimulation (FES), as applied in the management of dropped foot, on patients with chronic stroke and their carers. A qualitative phenomenological study was undertaken. Participants were recruited from the Lothian FES clinic. Data were collected by using semistructured face-to-face interviews and analysed by using the framework of interpretative phenomenological analysis (IPA). Thirteen patients and nine carers consented to participate in the study. The overarching theme that emerged from the data was that "FES impacted on important aspects of my life." Four subthemes were identified: 1) "Walking with FES is much better"; 2) "FES helped regain control of life"; 3) "Feeling good comes with using FES"; and 4) "FES is not perfect but it is of value." This study provides insights into the perceptions of patients and carers of the impact of FES. These results have implications for clinicians delivering an FES service for the management of dropped foot after stroke. © Informa Healthcare. USA, Inc

    Do NHS walk-in centres in England provide a model of integrated care?

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    PURPOSE: To undertake a comprehensive evaluation of NHS walk-in centres against criteria of improved access, quality, user satisfaction and efficiency. CONTEXT: Forty NHS walk-in centres have been opened in England, as part of the UK governments agenda to modernise the NHS. They are intended to improve access to primary care, provide high quality treatment at convenient times, and reduce inappropriate demand on other NHS providers. Care is provided by nurses rather than doctors, using computerised algorithms, and nurses use protocols to supply treatments previously only available from doctors. DATA SOURCES: Several linked studies were conducted using different sources of data and methodologies. These included routinely collected data, site visits, patient interviews, a survey of users of walk-in centres, a study using simulated patients to assess quality of care, analysis of consultation rates in NHS services near to walk-in centres, and audit of compliance with protocols. CONCLUSION & DISCUSSION: The findings illustrate many of the issues described in a recent WHO reflective paper on Integrated Care, including tensions between professional judgement and use of protocols, problems with incompatible IT systems, balancing users' demands and needs, the importance of understanding health professionals' roles and issues of technical versus allocative efficiency
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