6,963 research outputs found

    Optimizing diagnostic imaging through skills mix: costs and opportunities

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    YesIncreasing diagnostic capacity is a national priority to expedite the timeliness and appropriateness of patient treatment interventions. Imaging, encompassing a range of technologies including X-ray, Computer Tomography, Magnetic Resonance Imaging and ultrasound, is a key diagnostic service and central to decision making in most, if not all, disease pathways. However, imaging is an expensive discipline accounting for an estimated 3-5% of the annual NHS budget. As a result, it is imperative that we maximize service efficiency while optimizing patient outcomes

    The Impact of New EUV Diagnostics on CME-Related Kinematics

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    We present the application of novel diagnostics to the spectroscopic observation of a Coronal Mass Ejection (CME) on disk by the Extreme Ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. We apply a recently developed line profile asymmetry analysis to the spectroscopic observation of NOAA AR 10930 on 14-15 December 2006 to three raster observations before and during the eruption of a 1000km/s CME. We see the impact that the observer's line-of-sight and magnetic field geometry have on the diagnostics used. Further, and more importantly, we identify the on-disk signature of a high-speed outflow behind the CME in the dimming region arising as a result of the eruption. Supported by recent coronal observations of the STEREO spacecraft, we speculate about the momentum flux resulting from this outflow as a secondary momentum source to the CME. The results presented highlight the importance of spectroscopic measurements in relation to CME kinematics, and the need for full-disk synoptic spectroscopic observations of the coronal and chromospheric plasmas to capture the signature of such explosive energy release as a way of providing better constraints of CME propagation times to L1, or any other point of interest in the heliosphere.Comment: Accepted to appear in Solar Physics Topical Issue titled "Remote Sensing of the Inner Heliosphere". Manuscript has 14 pages, 5 color figures. Movies supporting the figures can be found in http://download.hao.ucar.edu/pub/mscott/papers/Weathe

    Solar activity during Skylab: Its distribution and relation to coronal holes

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    Solar active regions observed during the period of Skylab observations (May 1973-February 1974) were examined for properties that varied systematically with location on the sun, particularly with respect to the location of coronal holes. Approximately 90 percent of the optical and X-ray flare activity occurred in one solar hemisphere (136-315 heliographic degrees longitude). Active regions within 20 heliographic degrees of coronal holes were below average in lifetimes, flare production, and magnetic complexity. Histograms of solar flares as a function of solar longitude were aligned with H alpha synoptic charts on which active region serial numbers and coronal hole boundaries were added

    Scattering from a Domain Wall in a Spontaneously Broken Gauge Theory

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    We study the interaction of particles with a domain wall at a symmetry-breaking phase transition by perturbing about the domain wall solution. We find the particulate excitations appropriate near the domain wall and relate them to the particles present far from the wall in the uniform broken and unbroken phases. For a quartic Higgs potential we find analytic solutions to the equations of motion and derive reflection and transmission coefficients. We discover several bound states for particles near the wall. Finally, we apply our results to the electroweak phase transition in the standard model.Comment: 48 pages, 10 figures, LaTeX / epsf, revised to include references to earlier related wor

    On red shifs in the transition region and corona

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    We present evidence that transition region red-shifts are naturally produced in episodically heated models where the average volumetric heating scale height lies between that of the chromospheric pressure scale height of 200 km and the coronal scale height of 50 Mm. In order to do so we present results from 3d MHD models spanning the upper convection zone up to the corona, 15 Mm above the photosphere. Transition region and coronal heating in these models is due both the stressing of the magnetic field by photospheric and convection `zone dynamics, but also in some models by the injection of emerging magnetic flux.Comment: 8 pages, 9 figures, NSO Workshop #25 Chromospheric Structure and Dynamic

    Tidal effects and the Proximity decay of nuclei

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    We examine the decay of the 3.03 MeV state of 8^8Be evaporated from an excited projectile-like fragment following a peripheral heavy-ion collision. The relative energy of the daughter α\alpha particles exhibits a dependence on the decay angle of the 8^8Be^*, indicative of a tidal effect. Comparison of the measured tidal effect with a purely Coulomb model suggests the influence of a measurable nuclear proximity interaction.Comment: 5 pages, 4 figure

    Purely gravito-magnetic vacuum space-times

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    It is shown that there are no vacuum space-times (with or without cosmological constant) for which the Weyl-tensor is purely gravito-magnetic with respect to a normal and timelike congruence of observers.Comment: 4 page

    Attending to conditions that facilitate intercultural competence: A reciprocal service-learning approach

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    Although service-learning can support the development of intercultural competence, it has also maintained power differentials, reinforced privileged perspectives, and strengthened deficit thinking. Recent research has investigated the conditions within service-learning associated with positive change in diversity-related attitudes. We extend that work, conceptualizing a reciprocal service-learning (RSL) approach that integrates conditions posited by contact theory and the process model of intercultural competence into service-learning’s core features of reflection and reciprocity. In an RSL approach, transformational reciprocity at the participant level supports cultural awareness, interdependence, and parity between participant groups. We created an RSL experience and measured change in three attitudes fundamental to the development of intercultural competence with quantitative pre- and post-surveys. Results indicate that both participant groups—native English-speaking undergraduate students and international English language learners—experienced significant growth. This study responds to calls for quantitative pre- and post-research methods and the assessment of outcomes for all service-learning participants

    Axistationary perfect fluids -- a tetrad approach

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    Stationary axisymmetric perfect fluid space-times are investigated using the curvature description of geometries. Attention is focused on space-times with a vanishing electric part of the Weyl tensor. It is shown that the only incompressible axistationary magnetic perfect fluid is the interior Schwarzschild solution. The existence of a rigidly rotating perfect fluid, generalizing the interior Schwarzschild metric is proven. Theorems are stated on Petrov types and electric/magnetic Weyl tensors.Comment: 12 page
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