20,368 research outputs found

    Towards a National Injury Costing System?:Lessons from a Public-Private Injury Costing Pilot Study in South Africa

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    South Africa has extremely high incidence rates of fatal and non-fatal injuries due to interpersonal violence, pedestrian–motor vehicle collisions, burns, falls and other unintentional causes. Whilethe actual cost associated with these injuries remains relatively unknown, the estimated direct cost of the medical treatment, rehabilitation and administration of these victims may run into billionsof rands. This public–private injury costing pilot study (hereafter the study) was conducted at a tertiary public health facility in Johannesburg, South Africa (hereafter the public facility). The studyattempted to facilitate further costing capacity through skills transfers from personnel at a sentinel private health facility in Johannesburg (hereafter the private hospital) to selected personnel withinthe identified public facility, and through the determination of the partial baseline direct medical cost of the treatment of gun shot wounds, pedestrian–motor vehicle collision injuries, falls and burns at the public facility. Both the capacity building component and the actual study werecomplicated by a number of obstacles, including limited personnel, poor costing and billing capacity, underdeveloped billing documentation and recording procedures, and limited levels of investment in the general practice of injury costing in the public health sector itself. This articleexamines the practical challenges facing further attempts to describe the cost of injuries in South Africa. It concludes with several critical reflections on concerns associated with an uncritical pursuit of the roll-out of a national injury costing system, which may have a negative impact on service delivery to the very populations that encounter injuries as a public health sector priority

    Research and Theory Towards a National Injury Costing System?:Lessons from a Public-Private Injury Costing Pilot Study in South Africa

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    South Africa has extremely high incidence rates of fatal and non-fatal injuries due to interpersonal violence, pedestrian–motor vehicle collisions, burns, falls and other unintentional causes. While the actual cost associated with these injuries remains relatively unknown, the estimated direct cost of the medical treatment, rehabilitation and administration of these victims may run into billions of rands. This public–private injury costing pilot study (hereafter the study) was conducted at a tertiary public health facility in Johannesburg, South Africa (hereafter the public facility). The study attempted to facilitate further costing capacity through skills transfers from personnel at a sentinel private health facility in Johannesburg (hereafter the private hospital) to selected personnel within the identified public facility, and through the determination of the partial baseline direct medical cost of the treatment of gun shot wounds, pedestrian–motor vehicle collision injuries, falls and burns at the public facility. Both the capacity building component and the actual study were complicated by a number of obstacles, including limited personnel, poor costing and billing capacity, underdeveloped billing documentation and recording procedures, and limited levels of investment in the general practice of injury costing in the public health sector itself. This article examines the practical challenges facing further attempts to describe the cost of injuries in South Africa. It concludes with several critical reflections on concerns associated with an uncritical pursuit of the roll-out of a national injury costing system, which may have a negative impact on service delivery to the very populations that encounter injuries as a public health sector priority

    Earth’s albedo and its symmetry

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    Abstract The properties of Earth's albedo and its symmetries are analyzed using twenty years of space-based Energy Balanced And Filled product of Clouds and the Earth's Radiant Energy System measurements. Despite surface asymmetries, top of the atmosphere temporally & hemispherically averaged reflected solar irradiance R appears symmetric over Northern/Southern hemispheres. This is confirmed with the use of surrogate time-series, which provides margins of 0.1±0.28Wm?2 for possible hemispheric differences supported by Clouds and Earth's Radiant System data. R time-series are further analyzed by decomposition into a seasonal (yearly and half yearly) cycle and residuals. Variability in the reflected solar irradiance is almost entirely (99%) due to the seasonal variations, mostly due to seasonal variations in insolation. The residuals of hemispherically averaged R are not only small, but also indistinguishable from noise, and thus not correlated across hemispheres. This makes yearly and sub-yearly timescales unlikely as the basis for a symmetry-establishing mechanism. The residuals however contain a global trend that is large, as compared to expected albedo feedbacks. It is also hemispherically symmetric, and thus indicates the possibility of a symmetry enforcing mechanism at longer timescales. To pinpoint precisely which parts of the Earth system establish the hemispheric symmetry, we create an energetically consistent cloud-albedo field from the data. We show that the surface albedo asymmetry is compensated by asymmetries between clouds over extra-tropical oceans, with southern hemispheric storm-tracks being 11% cloudier than their northern hemisphere counterparts. This again indicates that, assuming the albedo symmetry is not a result of chance, its mechanism likely operates on large temporal and spatial scales

    Two Cases of Compound Fracture of the Leg

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    Absolute Calibration of the Radio Astronomy Flux Density Scale at 22 to 43 GHz Using Planck

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    The Planck mission detected thousands of extragalactic radio sources at frequencies from 28 to 857 GHz. Planck's calibration is absolute (in the sense that it is based on the satellite's annual motion around the Sun and the temperature of the cosmic microwave background), and its beams are well characterized at sub-percent levels. Thus Planck's flux density measurements of compact sources are absolute in the same sense. We have made coordinated VLA and ATCA observations of 65 strong, unresolved Planck sources in order to transfer Planck's calibration to ground-based instruments at 22, 28, and 43 GHz. The results are compared to microwave flux density scales currently based on planetary observations. Despite the scatter introduced by the variability of many of the sources, the flux density scales are determined to 1-2% accuracy. At 28 GHz, the flux density scale used by the VLA runs 3.6% +- 1.0% below Planck values; at 43 GHz, the discrepancy increases to 6.2% +- 1.4% for both ATCA and the VLA.Comment: 16 pages, 4 figures and 4 table

    The effect of surface treatment on delamination for a nylon interleaving material

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    One method of controlling delamination and increasing the inter-lamina toughness in composite laminates is the use of thermoplastic interleaving films, primarily to absorb energy. In this study the effect of controlling the surface energy of a nylon interleaving film on the interlaminar fracture toughness was investigated. It was found that as the surface energy of the nylon increased so did the Mode I delamination resistance. Surface energy was measured via dynamic contact angle measurements and delamination resistance via double cantilever beam specimens. It was concluded that control of the surface energy of the interleaving material is paramount in controlling delamination. © Institute of Materials Engineering Australasia Ltd

    Ray-optical negative refraction and pseudoscopic imaging with Dove-prism arrays

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    A sheet consisting of an array of small, aligned Dove prisms can locally (on the scale of the width of the prisms) invert one component of the ray direction. A sandwich of two such Dove-prism sheets that inverts both transverse components of the ray direction is a ray-optical approximation to the interface between two media with refractive indices +n and –n. We demonstrate the simulated imaging properties of such a Dove-prism-sheet sandwich, including a demonstration of pseudoscopic imaging

    Evolutionary design of a full-envelope full-authority flight control system for an unstable high-performance aircraft

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    The use of an evolutionary algorithm in the framework of H1 control theory is being considered as a means for synthesizing controller gains that minimize a weighted combination of the infinite norm of the sensitivity function (for disturbance attenuation requirements) and complementary sensitivity function (for robust stability requirements) at the same time. The case study deals with a complete full-authority longitudinal control system for an unstable high-performance jet aircraft featuring (i) a stability and control augmentation system and (ii) autopilot functions (speed and altitude hold). Constraints on closed-loop response are enforced, that representing typical requirements on airplane handling qualities, that makes the control law synthesis process more demanding. Gain scheduling is required, in order to obtain satisfactory performance over the whole flight envelope, so that the synthesis is performed at different reference trim conditions, for several values of the dynamic pressure, used as the scheduling parameter. Nonetheless, the dynamic behaviour of the aircraft may exhibit significant variations when flying at different altitudes, even for the same value of the dynamic pressure, so that a trade-off is required between different feasible controllers synthesized at different altitudes for a given equivalent airspeed. A multiobjective search is thus considered for the determination of the best suited solution to be introduced in the scheduling of the control law. The obtained results are then tested on a longitudinal non-linear model of the aircraft
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