1,362 research outputs found

    Proximal femoral fracture in a man resulting from modern clipless pedals: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>The use of clipless pedals amongst recreational cyclists has become increasingly popular in recent years. We describe a hip fracture, that was sustained due to inadequate set up of such pedals. To the best of our knowledge, this has only been described once before, and this was in the non-English language medical literature.</p> <p>Case Report</p> <p>A 38-year-old Caucasian man who was a club cyclist sustained a displaced intracapsular fracture of the hip whilst cycling. As a direct result of the incorrect set-up of his clipless pedals he was unable to release his feet whilst slowing to a halt. This resulted in a loss of balance and subsequent fall with a direct impact onto his left hip. The resulting fracture was managed successfully with early closed reduction and fixation. At six month review he was walking unaided without pain but, as yet, has been unable to return to cycling.</p> <p>Conclusion</p> <p>This case highlights the dangers of clipless pedals even in experienced cyclists, and underlines the importance of proper information for their correct setup to minimise the risk of potentially serious injuries, especially in the region of the hip.</p

    Satellite mapping in cities and below cities: how good is it now?

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    Global navigation satellite systems (GNSS) have existed since the launch of the US global positioning system constellation in 1978. There is an increasing need for better maps in the digital age, particularly for buried utilities. One of the most convenient methods for creating accurate maps is the use of navigation satellites for positioning. However, built-up urban areas are not ideal for the use of this positioning technology. This paper provides an update on the situation regarding GNSS and assesses how new satellites and signals are contributing to better positioning availability by carrying out a test in a controlled environment. The results show that using combined satellite systems improves availability in urban canyons in some cases, but not in all scenarios. In addition, pipeline mapping technology has been tested and been shown to be an effective means of mapping pipes deep under the ground over short distances

    The Stokes Phenomenon and Quantum Tunneling for de Sitter Radiation in Nonstationary Coordinates

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    We study quantum tunneling for the de Sitter radiation in the planar coordinates and global coordinates, which are nonstationary coordinates and describe the expanding geometry. Using the phase-integral approximation for the Hamilton-Jacobi action in the complex plane of time, we obtain the particle-production rate in both coordinates and derive the additional sinusoidal factor depending on the dimensionality of spacetime and the quantum number for spherical harmonics in the global coordinates. This approach resolves the factor of two problem in the tunneling method.Comment: LaTex 10 pages, no figur

    Current Practice in Vitamin D Management in Allogeneic Hematopoietic Stem Cell Transplantation: A Survey by the Transplant Complications Working Party of the European Society for Blood and Marrow Transplantation

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    Beyond its impact on bone health, numerous studies have investigated the immune-regulatory properties of vitamin D and shown how its deficiency can affect outcomes in allogeneic hematopoietic stem cell transplantation (HSCT), particularly in acute or chronic graft-versus-host disease. This survey, carried out by the Transplant Complications Working Party of the European Society for Blood and Marrow Transplantation (EBMT), describes the current clinical practice discrepancies across the EBMT HSCT programs. We therefore recommend the development of evidence-based guidelines to standardize evaluation criteria and to harmonize the management of vitamin D deficiency in patients undergoing allogeneic HSCT

    Estimation of coronary wave intensity analysis using noninvasive techniques and its application to exercise physiology

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    Wave intensity analysis (WIA) has found particular applicability in the coronary circulation where it can quantify traveling waves that accelerate and decelerate blood flow. The most important wave for the regulation of flow is the backward-traveling decompression wave (BDW). Coronary WIA has hitherto always been calculated from invasive measures of pressure and flow. However, recently it has become feasible to obtain estimates of these waveforms noninvasively. In this study we set out to assess the agreement between invasive and noninvasive coronary WIA at rest and measure the effect of exercise. Twenty-two patients (mean age 60) with unobstructed coronaries underwent invasive WIA in the left anterior descending artery (LAD). Immediately afterwards, noninvasive LAD flow and pressure were recorded and WIA calculated from pulsed-wave Doppler coronary flow velocity and central blood pressure waveforms measured using a cuff-based technique. Nine of these patients underwent noninvasive coronary WIA assessment during exercise. A pattern of six waves were observed in both modalities. The BDW was similar between invasive and noninvasive measures [peak: 14.9 ± 7.8 vs. -13.8 ± 7.1 × 10(4) W·m(-2)·s(-2), concordance correlation coefficient (CCC): 0.73, P < 0.01; cumulative: -64.4 ± 32.8 vs. -59.4 ± 34.2 × 10(2) W·m(-2)·s(-1), CCC: 0.66, P < 0.01], but smaller waves were underestimated noninvasively. Increased left ventricular mass correlated with a decreased noninvasive BDW fraction (r = -0.48, P = 0.02). Exercise increased the BDW: at maximum exercise peak BDW was -47.0 ± 29.5 × 10(4) W·m(-2)·s(-2) (P < 0.01 vs. rest) and cumulative BDW -19.2 ± 12.6 × 10(3) W·m(-2)·s(-1) (P < 0.01 vs. rest). The BDW can be measured noninvasively with acceptable reliably potentially simplifying assessments and increasing the applicability of coronary WIA

    Stationary Black Holes: Uniqueness and Beyond

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    The spectrum of known black-hole solutions to the stationary Einstein equations has been steadily increasing, sometimes in unexpected ways. In particular, it has turned out that not all black-hole-equilibrium configurations are characterized by their mass, angular momentum and global charges. Moreover, the high degree of symmetry displayed by vacuum and electro-vacuum black-hole spacetimes ceases to exist in self-gravitating non-linear field theories. This text aims to review some developments in the subject and to discuss them in light of the uniqueness theorem for the Einstein-Maxwell system.Comment: Major update of the original version by Markus Heusler from 1998. Piotr T. Chru\'sciel and Jo\~ao Lopes Costa succeeded to this review's authorship. Significantly restructured and updated all sections; changes are too numerous to be usefully described here. The number of references increased from 186 to 32
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