2,159 research outputs found

    Broadband sensitivity enhancement of detuned dual-recycled Michelson interferometers with EPR entanglement

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    We demonstrate the applicability of the EPR entanglement squeezing scheme for enhancing the shot-noise-limited sensitivity of a detuned dual-recycled Michelson interferometers. In particular, this scheme is applied to the GEO\,600 interferometer. The effect of losses throughout the interferometer, arm length asymmetries, and imperfect separation of the signal and idler beams are considered

    Testicular infarction secondary to protein S deficiency: a case report

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    BACKGROUND: Protein S deficiency is an inherited cause of thrombophilia. We present the second reported case in the literature of a man developing testicular infarction secondary to protein S deficiency. CASE PRESENTATION: A 63 year old man presented with sudden onset of pain in his left hemi-scrotum. Despite oral warfarin therapy the plasma INR was only 1.4 at presentation. Doppler ultrasound scan of the scrotum confirmed absent blood flow to the left testis with increased echogenicity. Orchidectomy was performed to remove the necrotic testis. Post-operatively the patient did well and was referred to the Regional Haemophilia and Thrombosis Centre for further management. CONCLUSION: The case highlights a rare but potential complication of protein S deficiency and demonstrates the importance of adequate anticoagulation in these patients

    Fundamental Limitations of Cavity-assisted Atom Interferometry

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    Atom interferometers employing optical cavities to enhance the beam splitter pulses promise significant advances in science and technology, notably for future gravitational wave detectors. Long cavities, on the scale of hundreds of meters, have been proposed in experiments aiming to observe gravitational waves with frequencies below 1 Hz, where laser interferometers, such as LIGO, have poor sensitivity. Alternatively, short cavities have also been proposed for enhancing the sensitivity of more portable atom interferometers. We explore the fundamental limitations of two-mirror cavities for atomic beam splitting, and establish upper bounds on the temperature of the atomic ensemble as a function of cavity length and three design parameters: the cavity g-factor, the bandwidth, and the optical suppression factor of the first and second order spatial modes. A lower bound to the cavity bandwidth is found which avoids elongation of the interaction time and maximizes power enhancement. An upper limit to cavity length is found for symmetric two-mirror cavities, restricting the practicality of long baseline detectors. For shorter cavities, an upper limit on the beam size was derived from the geometrical stability of the cavity. These findings aim to aid the design of current and future cavity-assisted atom interferometers.Comment: 11 pages, 12 figure

    Effects of Exercise Intensity on Postexercise Endothelial Function and Oxidative Stress

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    Purpose. To measure endothelial function and oxidative stress immediately, 90 minutes, and three hours after exercise of varying intensities. Methods. Sixteen apparently healthy men completed three exercise bouts of treadmill running for 30 minutes at 55% V˙O2max (mild); 20 minutes at 75% V˙O2max (moderate); or 5 minutes at 100% V˙O2max (maximal) in random order. Brachial artery flow-mediated dilation (FMD) was assessed with venous blood samples drawn for measurement of endothelin-1 (ET-1), lipid hydroperoxides (LOOHs), and lipid soluble antioxidants. Results. LOOH increased immediately following moderate exercise (P<0.05). ET-1 was higher immediately after exercise and 3 hours after exercise in the mild trial compared to maximal one (P<0.05). Transient decreases were detected for ΔFMD/ShearAUC from baseline following maximal exercise, but it normalised at 3 hours after exercise (P<0.05). Shear rate was higher immediately after exercise in the maximal trial compared to mild exercise (P<0.05). No changes in baseline diameter, peak diameter, absolute change in diameter, or FMD were observed following any of the exercise trials (P>0.05). Conclusions. Acute exercise at different intensities elicits varied effects on oxidative stress, shear rate, and ET-1 that do not appear to mediate changes in endothelial function measured by FMD

    Bolstering Mission Success: Lessons Learned for Small Satellite Developers Adhering to Manned Spaceflight Requirements

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    This paper is meant to impart critical knowledge to new and upcoming spacecraft developers (universities, high schools, research centers, young commercial companies, etc.) regarding lessons learned that they can implement to create successful spacecraft missions. This perspective comes from NanoRacks, a “space access provider”, where we’ve gained enormous expertise on how to design and build to requirements driven by human-rated spaceflight. As we all know, operating in space is only half of the battle

    Feasibility of near-unstable cavities for future gravitational wave detectors

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    Near-unstable cavities have been proposed as an enabling technology for future gravitational wave detectors, as their compact structure and large beam spots can reduce the coating thermal noise of the interferometer. We present a tabletop experiment investigating the behaviour of an optical cavity as it is parametrically pushed to geometrical instability. We report on the observed degeneracies of the cavity's eigenmodes as the cavity becomes unstable and the resonance conditions become hyper-sensitive to mirror surface imperfections. A simple model of the cavity and precise measurements of the resonant frequencies allow us to characterize the stability of the cavity and give an estimate of the mirror astigmatism. The significance of these results for gravitational wave detectors is discussed, and avenues for further research are suggested.Comment: 11 pages, 8 figure

    A Systematic Review of the Acute Effects of Exercise on Immune and Inflammatory Indices in Untrained Adults

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    BACKGROUND: Cardiovascular disease (CVD) is the leading cause of global mortality. Although the incidence may be reduced with regular exercise, the health benefits of a single bout of exercise on selected CVD risk factors are not well understood. The primary objective of this review is to consider the transient effects of exercise on immune (neutrophil count) and inflammatory (interleukin-6 [IL-6], C-reactive protein [CRP]) markers in untrained adults. METHODS: MEDLINE, EMBASE, CINAHL, Sports Discus and Cochrane were searched for relevant studies published from January 1946 to May 2013. Randomised controlled or crossover studies which measured any of these parameters in untrained but otherwise healthy participants in the 48 h following about of exercise, less than 1 h in duration were included. RESULTS: Ten studies met the inclusion criteria. The results indicate a single bout of aerobic or resistance exercise of moderate to high intensity promotes an increase in IL-6 (145 %) and neutrophil counts (51 %). It appears that 30–60 min of moderate to high intensity exercise is necessary to elicit such changes although variables such as the mode, intensity and pattern of exercise also affect the response. The acute response of CRP within the included studies is equivocal. CONCLUSIONS: Although responses to CRP are inconsistent, a single bout of exercise can increase the activity of both circulating IL-6 and neutrophil counts in untrained adults. These immune and inflammatory responses to a single bout of exercise may be linked to a range of health benefits

    Partnered care: insights from economic theories of the firm

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    This paper offers ideas as to how economic theories of the firm might be used as a lens to inform the development of the Partnered Health Care Model of healthcare delivery in The Bahamas. The model is explained, concepts are offered and implications suggested
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