825 research outputs found

    Embracing virtual outpatient clinics in the era of COVID-19

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    The response to the COVID-19 pandemic has raised the profile and level of interest in the use, acceptability, safety and effectiveness of virtual outpatient consultations and telemedicine. These models of care are not new but a number of challenges have so far hindered widespread take up and endorsement of these ways of working. With the response to the COVID-19 pandemic, remote and virtual working and consultation have become the default. This paper explores our experience of and learning from virtual and remote consultation and questions how this experience can be retained and developed for the future

    Quadratic Lagrangians and Topology in Gauge Theory Gravity

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    We consider topological contributions to the action integral in a gauge theory formulation of gravity. Two topological invariants are found and are shown to arise from the scalar and pseudoscalar parts of a single integral. Neither of these action integrals contribute to the classical field equations. An identity is found for the invariants that is valid for non-symmetric Riemann tensors, generalizing the usual GR expression for the topological invariants. The link with Yang-Mills instantons in Euclidean gravity is also explored. Ten independent quadratic terms are constructed from the Riemann tensor, and the topological invariants reduce these to eight possible independent terms for a quadratic Lagrangian. The resulting field equations for the parity non-violating terms are presented. Our derivations of these results are considerably simpler that those found in the literature

    Detection of X-ray galaxy clusters based on the Kolmogorov method

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    The detection of clusters of galaxies in large surveys plays an important part in extragalactic astronomy, and particularly in cosmology, since cluster counts can give strong constraints on cosmological parameters. X-ray imaging is in particular a reliable means to discover new clusters, and large X-ray surveys are now available. Considering XMM-Newton data for a sample of 40 Abell clusters, we show that their analysis with a Kolmogorov distribution can provide a distinctive signature for galaxy clusters. The Kolmogorov method is sensitive to the correlations in the cluster X-ray properties and can therefore be used for their identification, thus allowing to search reliably for clusters in a simple way

    SANEPIC: A Map-Making Method for Timestream Data From Large Arrays

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    We describe a map-making method which we have developed for the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) experiment, but which should have general application to data from other submillimeter arrays. Our method uses a Maximum Likelihood based approach, with several approximations, which allows images to be constructed using large amounts of data with fairly modest computer memory and processing requirements. This new approach, Signal And Noise Estimation Procedure Including Correlations (SANEPIC), builds upon several previous methods, but focuses specifically on the regime where there is a large number of detectors sampling the same map of the sky, and explicitly allowing for the the possibility of strong correlations between the detector timestreams. We provide real and simulated examples of how well this method performs compared with more simplistic map-makers based on filtering. We discuss two separate implementations of SANEPIC: a brute-force approach, in which the inverse pixel-pixel covariance matrix is computed; and an iterative approach, which is much more efficient for large maps. SANEPIC has been successfully used to produce maps using data from the 2005 BLAST flight.Comment: 27 Pages, 15 figures; Submitted to the Astrophysical Journal; related results available at http://blastexperiment.info/ [the BLAST Webpage

    Do patients accurately represent their experiences after hip and knee replacements?

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    Background To investigate discrepancies, if any, between the complications that patients report on the patient-reported outcome measures (PROMs) questionnaire and what is formally recorded in their medical records. Methodology A retrospective analysis of PROMs-reported complications was performed at a single elective center for all patients who had an elective primary total knee or hip replacement between April 2016 and March 2017. Corresponding patient medical records were then analyzed to correlate the PROMs with any documentation of postoperative complications, which similar to the PROMs data were categorized into wound complications, urinary complications, readmission, and further operative procedures. Results A set of 54 complete patient records were compared to the corresponding PROMs data. The combined overall positive predictive value was 0.47 while the overall negative predictive value was 0.91. Concordance between patients and the medical records was 70.4% for wound complication, 66.7% for urinary complications, 83.3% for readmission, and 96.3% for reoperation. Conclusion PROMs data are becoming increasingly important in auditing and planning healthcare provision. This study highlights a significant level of discrepancy between the PROMs-reported complication rates and those documented in the medical records. There is a visible disparity between patient perception and the medical definition of postoperative complications. Further patient education and empowerment are required in preparation for arthroplasty

    All-sky convolution for polarimetry experiments

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    We discuss all-sky convolution of the instrument beam with the sky signal in polarimetry experiments, such as the Planck mission which will map the temperature anisotropy and polarization of the cosmic microwave background (CMB). To account properly for stray light (from e.g. the galaxy, sun, and planets) in the far side-lobes of such an experiment, it is necessary to perform the beam convolution over the full sky. We discuss this process in multipole space for an arbitrary beam response, fully including the effects of beam asymmetry and cross-polarization. The form of the convolution in multipole space is such that the Wandelt-Gorski fast technique for all-sky convolution of scalar signals (e.g. temperature) can be applied with little modification. We further show that for the special case of a pure co-polarized, axisymmetric beam the effect of the convolution can be described by spin-weighted window functions. In the limits of a small angle beam and large Legendre multipoles, the spin-weight 2 window function for the linear polarization reduces to the usual scalar window function used in previous analyses of beam effects in CMB polarimetry experiments. While we focus on the example of polarimetry experiments in the context of CMB studies, we emphasise that the formalism we develop is applicable to anisotropic filtering of arbitrary tensor fields on the sphere.Comment: 8 pages, 1 figure; Minor changes to match version accepted by Phys. Rev.

    Political Leadership as Statecraft? Aligning Theory with Praxis in Conversation with British Party Leaders

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    How should prime ministerial and party leadership be understood and assessed? One leading approach posits that we should assess them in terms of whether they achieve statecraft, that is, winning and maintain office in government. This article supplements and then assesses that theory by drawing from Pawson and Tilley’s (1997) concept of the realistic interview, in which practitioners are deployed as co-researchers to assess and revise theory. Unprecedented interviews with British party leaders were therefore undertaken. The article provides new empirical support for the framework because many of the key generative mechanisms identified within the neo-statecraft model were present in an analysis of the interviews. The interviews also allowed the limitations of the model to be demarcated. Statecraft focusses purely on cunning leadership where the aim is to maximise power and influence. This differs from leadership by conscious where the aim is to achieve normative goals

    28 -- 40 GHz variability and polarimetry of bright compact sources in the QUIJOTE cosmological fields

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    We observed 51 sources in the Q-U-I JOint TEnerife (QUIJOTE) cosmological fields which were brighter than 1 Jy at 30 GHz in the Planck Point Source Catalogue (version 1), with the Very Large Array at 28 -- 40 GHz, in order to characterise their high-radio-frequency variability and polarization properties. We find a roughly log-normal distribution of polarization fractions with a median of 2%, in agreement with previous studies, and a median rotation measure (RM) of \approx 1110 rad m2^{-2} with one outlier up to \approx 64000 rad m2^{-2} which is among the highest RMs measured in quasar cores. We find hints of a correlation between the total intensity flux density and median polarization fraction. We find 59% of sources are variable in total intensity, and 100% in polarization at 3σ3\sigma level, with no apparent correlation between total intensity variability and polarization variability. This indicates that it will be difficult to model these sources without simultaneous polarimetric monitoring observations and they will need to be masked for cosmological analysis.Comment: 17 pages, 14 figures, accepted to MNRA
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