13,157 research outputs found

    Attitudes and access to lung volume reduction surgery for COPD: a survey by the British Thoracic Society.

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    OBJECTIVE: Lung volume reduction surgery for emphysema leads to improved survival in appropriately selected individuals, and it is therefore recommended in national and international guidelines for this group of patients. Despite this, fewer than 100 patients undergo the procedure each year in the UK. Our objective was to establish whether this reflects concerns about morbidity and mortality or difficulties in the referral pathway. DESIGN AND SETTING: We conducted a survey of members of the British Thoracic Society by email to investigate this in the second half of 2013. The survey included questions about access to investigations, the indications for lung volume reduction surgery (LVRS), whether a multidisciplinary meeting discussed eligibility of patients for LVRS and what the morbidity and mortality associated with the procedure was. RESULTS: There were 65 responses, 82% from respiratory physicians. Roughly half of the respondents were either unsure about the risks of death or prolonged (>30 days) hospital stay involved or significantly over-estimated them. In total, 70% did not have a specific multidisciplinary team to discuss the management of patients with advanced chronic obstructive pulmonary disease (COPD). There was no consensus as to which patients with COPD should undergo a CT scan to evaluate them for possible surgery. CONCLUSIONS: Patients with COPD require a systematic and multidisciplinary approach to assessment for LVRS and these survey data suggest that work is needed to deliver this evidence-based therapy in a consistent and comprehensive way across the UK

    Challenges to smartphone applications for melanoma detection

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    This commentary addresses the emerging market for health-related smartphone applications. Specific to dermatology, there has been a significant increase not only in applications that promote skin cancer awareness and education but also in those meant for detection. With evidence showing that 365 dermatology-related applications were available in 2014--up from 230 in 2012--and that 1 in 5 patients under the age of 50 have used a smartphone to help diagnose a skin problem, there is clearly a large subset of patients participating in this growing trend. Therefore, we are obligated to take a closer look into this phenomenon. Studies have shown that applications are inferior to in-person consultations with one study showing that 3 out of 4 applications incorrectly classified 30% or more melanomas as low-risk lesions. Although the FDA gained regulatory oversight over mobile health applications in 2012 and recently released their statement in 2015, their reach only extends to cover a selected portion of these applications, leaving many unregulated as they continue to be marketed toward our patients. Dermatologists should be updated on our current situation in order to properly counsel patients on the risks and benefits of these applications and whether they are acceptable for use. © 2016 by the article author(s)

    Using HINODE/Extreme-Ultraviolet Imaging Spectrometer to confirm a seismologically inferred coronal temperature

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    The Extreme-Ultraviolet Imaging Spectrometer on board the HINODE satellite is used to examine the loop system described in Marsh et al. (2009) by applying spectroscopic diagnostic methods. A simple isothermal mapping algorithm is applied to determine where the assumption of isothermal plasma may be valid, and the emission measure locii technique is used to determine the temperature profile along the base of the loop system. It is found that, along the base, the loop has a uniform temperature profile with a mean temperature of 0.89 +- 0.09 MK which is in agreement with the temperature determined seismologically in Marsh et al. (2009), using observations interpreted as the slow magnetoacoustic mode. The results further strengthen the slow mode interpretation, propagation at a uniform sound speed, and the analysis method applied in Marsh et al. (2009). It is found that it is not possible to discriminate between the slow mode phase speed and the sound speed within the precision of the present observations

    Phase-resolved far-ultraviolet HST spectroscopy of the peculiar magnetic white dwarf RE J0317-853

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    We present phase resolved FUV HST FOS spectra of the rapidly rotating, highly magnetic white dwarf RE J0317-853. Using these data, we construct a new model for the magnetic field morphology across the stellar surface. From an expansion into spherical harmonics, we find the range of magnetic field strengths present is 180-800MG. For the first time we could identify an absorption feature present at certain phases at 1160A as a ``forbidden'' 1s_0 -> 2s_0 component, due to the combined presence of an electric and magnetic field.Comment: 15 pages including 4 figures. Accepted for publication in ApJ Letter

    Accurate Reaction-Diffusion Operator Splitting on Tetrahedral Meshes for Parallel Stochastic Molecular Simulations

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    Spatial stochastic molecular simulations in biology are limited by the intense computation required to track molecules in space either in a discrete time or discrete space framework, meaning that the serial limit has already been reached in sub-cellular models. This calls for parallel simulations that can take advantage of the power of modern supercomputers; however exact methods are known to be inherently serial. We introduce an operator splitting implementation for irregular grids with a novel method to improve accuracy, and demonstrate potential for scalable parallel simulations in an initial MPI version. We foresee that this groundwork will enable larger scale, whole-cell stochastic simulations in the near future.Comment: 33 pages, 10 figure

    Quantum Discord and Quantum Computing - An Appraisal

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    We discuss models of computing that are beyond classical. The primary motivation is to unearth the cause of nonclassical advantages in computation. Completeness results from computational complexity theory lead to the identification of very disparate problems, and offer a kaleidoscopic view into the realm of quantum enhancements in computation. Emphasis is placed on the `power of one qubit' model, and the boundary between quantum and classical correlations as delineated by quantum discord. A recent result by Eastin on the role of this boundary in the efficient classical simulation of quantum computation is discussed. Perceived drawbacks in the interpretation of quantum discord as a relevant certificate of quantum enhancements are addressed.Comment: To be published in the Special Issue of the International Journal of Quantum Information on "Quantum Correlations: entanglement and beyond." 11 pages, 4 figure

    An astronomical search for evidence of new physics: Limits on gravity-induced birefringence from the magnetic white dwarf RE J0317-853

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    The coupling of the electromagnetic field directly with gravitational gauge fields leads to new physical effects that can be tested using astronomical data. Here we consider a particular case for closer scrutiny, a specific nonminimal coupling of torsion to electromagnetism, which enters into a metric-affine geometry of space-time. We show that under the assumption of this nonminimal coupling, spacetime is birefringent in the presence of such a gravitational field. This leads to the depolarization of light emitted from extended astrophysical sources. We use polarimetric data of the magnetic white dwarf REJ0317−853{RE J0317-853} to set strong constraints on the essential coupling constant for this effect, giving k^2 \lsim (19 {m})^2 .Comment: Statements about Moffat's NGT modified. Accepted for publication in Phys.Rev.

    Symmetric three-particle motion in Stokes flow: equilibrium for heavy spheres in contrast to "end-of-world" for point forces

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    A stationary stable solution of the Stokes equations for three identical heavy solid spheres falling in a vertical plane is found. It has no analog in the point-particle approximation. Three spheres aligned horizontally at equal distances evolve towards the equilibrium relative configuration while the point particles collapse onto a single point in a finite time.Comment: 4 pages, 7 figure
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