151 research outputs found

    Up-beat UK: a programme of research into the relationship between coronary heart disease and depression in primary care patients.

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    Coronary heart disease and depression are both common health problems and by 2020 will be the two leading causes of disability worldwide. Depression has been found to be more common in patients with coronary heart disease but the nature of this relationship is uncertain. In the United Kingdom general practitioners are now being remunerated for case-finding for depression in patients with coronary heart disease, however it is unclear how general practitioners should manage these patients. We aim to explore the relationship between coronary heart disease and depression in a primary care population and to develop an intervention for patients with coronary heart disease and depression

    Design and characterisation of the new CIS115 sensor for JANUS, the high resolution camera on JUICE

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    JUICE, the Jupiter Icy Moon Explorer, is a European Space Agency L-class mission destined for the Jovian system. Due for launch in 2022, it will begin a science phase after its transit to Jupiter that will include detailed investigations of three of the Galilean moons: Ganymede, Callisto and Europa. JUICE will carry payloads to characterise the Jovian environments, divided into in situ, geophysical and remote sensing packages. A key instrument in the remote sensing package is JANUS, an optical camera operating over a wavelength range of 350 nm to 1064 nm. JANUS will be used to study the external layers of Jupiter’s atmosphere, the ring system and the planetary bodies. To achieve the science goals, resolutions of better than 5 m per pixel are required for the highest resolution observations during the 200 km altitude orbit of Ganymede, whilst the system is operated with a signal to noise ratio of better than 100. Jupiter’s magnetic field is a dominant object in the solar system, trapping electrons and other charged particles leading to the radiation environment around Jupiter being very hostile, especially in the regions closest to Jupiter in the Ganymede orbit. The radiation tolerance of the focal plane detector in JANUS is therefore a major concern and radiation testing is vital to confirm its expected performance after irradiation will meet requirements set by the science goals. JANUS will be using a detector from e2v technologies plc, the CMOS Imaging Sensor 115 (CIS115), which is a device manufactured using 0.18 μm Imaging CMOS Process with a 2000 by 1504 pixel array each 7 μm square. The pixels have a 4T pinned photodiode pixel architecture, and the array is read out through four differential analogue outputs. This paper describes the preliminary characterisation of the CIS115, and results obtained with the CIS107 precursor sensor

    Semilocal Topological Defects

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    Semilocal defects are those formed in field theories with spontaneously broken symmetries, where the vacuum manifold MM is fibred by the action of the gauge group in a non-trivial way. Studied in this paper is the simplest such class of theories, in which M≃S2N−1M\simeq S^{2N-1}, fibred by the action of a local U(1)U(1) symmetry. Despite MM having trivial homotopy groups up to π2N−2\pi_{2N-2}, this theory exhibits a fascinating variety of defects: vortices, or semilocal strings; monopoles (on which the strings terminate); and (when N=2N=2) textures, which may be stabilised by their associated magnetic field to produce a skyrmion.Comment: 28pp, DAMTP-HEP-92-2

    Where are the Hedgehogs in Nematics?

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    In experiments which take a liquid crystal rapidly from the isotropic to the nematic phase, a dense tangle of defects is formed. In nematics, there are in principle both line and point defects (``hedgehogs''), but no point defects are observed until the defect network has coarsened appreciably. In this letter the expected density of point defects is shown to be extremely low, approximately 10−810^{-8} per initially correlated domain, as result of the topology (specifically, the homology) of the order parameter space.Comment: 6 pages, latex, 1 figure (self-unpacking PostScript)

    Adherence to General Diabetes and Foot Care Processes, with Prompt Referral, Are Associated with Amputation-Free Survival in People with Type 2 Diabetes and Foot Ulcers:: A Scottish National Registry Analysis

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    AIMS: To compare different packages of care across care providers in Scotland on foot-related outcomes. METHODS: A retrospective cohort study with primary and secondary care electronic health records from the Scottish Diabetes Registry, including 6,845 people with type 2 diabetes and a first foot ulcer occurring between 2013 and 2017. We assessed the association between exposure to care processes and major lower extremity amputation and death. Proportional hazards were used for time-to-event univariate and multivariate analyses, adjusting for case-mix characteristics and care processes. Results were expressed in terms of hazard ratios with 95% confidence intervals. RESULTS: 2,243 (32.7%) subjects had a major amputation or death. Exposure to all nine care processes at all ages (HR = 0.63; 95% CI: 0.58-0.69; p 70 years (HR = 0.88; 0.78-0.99; p = .03) were associated with longer major amputation-free survival. Waiting time ≥ 12 weeks between ulceration and clinic attendance was associated with worse outcomes (HR = 1.59; 1.37-1.84; p 70 years, minor amputations were associated with improved major amputation-free survival (HR = 0.69; 0.52-0.92; p = .01). CONCLUSIONS: Strict adherence to a standardised package of general diabetes care before foot ulceration, timely foot care after ulceration, and specific treatment pathways were associated with longer major amputation-free survival among a large cohort of people with type 2 diabetes in Scotland, with a larger impact on older age groups

    Universality and Critical Phenomena in String Defect Statistics

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    The idea of biased symmetries to avoid or alleviate cosmological problems caused by the appearance of some topological defects is familiar in the context of domain walls, where the defect statistics lend themselves naturally to a percolation theory description, and for cosmic strings, where the proportion of infinite strings can be varied or disappear entirely depending on the bias in the symmetry. In this paper we measure the initial configurational statistics of a network of string defects after a symmetry-breaking phase transition with initial bias in the symmetry of the ground state. Using an improved algorithm, which is useful for a more general class of self-interacting walks on an infinite lattice, we extend the work in \cite{MHKS} to better statistics and a different ground state manifold, namely RP2\R P^2, and explore various different discretisations. Within the statistical errors, the critical exponents of the Hagedorn transition are found to be quite possibly universal and identical to the critical exponents of three-dimensional bond or site percolation. This improves our understanding of the percolation theory description of defect statistics after a biased phase transition, as proposed in \cite{MHKS}. We also find strong evidence that the existence of infinite strings in the Vachaspati Vilenkin algorithm is generic to all (string-bearing) vacuum manifolds, all discretisations thereof, and all regular three-dimensional lattices.Comment: 62 pages, plain LaTeX, macro mathsymb.sty included, figures included. also available on http://starsky.pcss.maps.susx.ac.uk/groups/pt/preprints/96/96011.ps.g

    Penetrometry of granular and moist planetary surface materials: Application to the Huygens landing site on Titan

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    The Huygens probe landed on the then unknown surface of Titan in January 2005. A small, protruding penetrometer, part of the Surface Science Package (SSP), was pushed into the surface material measuring the mechanical resistance of the ground as the probe impacted the landing site. We present laboratory penetrometry into room temperature surface analogue materials using a replica penetrometer to investigate further the nature of Titan's surface and examine the sensor's capabilities. The results are then compared to the flight instrument's signature and suggest the Titan surface substrate material consists of sand-sized particles with a mean grain size ~2 mm. A possible thin 7 mm coating with mechanical properties similar to terrestrial snow may overlie this substrate, although due to the limited data we are unable to detect any further layering or grading within the near-surface material. The unusual weakening with depth of the signature returned from Titan has, to date, only been reproduced using a damp sand target that becomes progressively wetter with depth, and supports the suggestion that the surface may consist of a damp and cohesive material with interstitial liquid contained between its grains. Comparison with terrestrial analogues highlights the unusual nature of the landing site material
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