2,989 research outputs found

    Equivalent random analysis of a buffered optical switch with general interarrival times

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    We propose an approximate analytic model of an optical switch with fibre delay lines and wavelength converters by employing Equivalent Random Theory. General arrival traffic is modelled by means of Gamma-distributed interarrival times. The analysis is formulated in terms of virtual traffic flows within the optical switch from which we derive expressions for burst blocking probability, fibre delay line occupancy and mean delay. Emphasis is on approximations that give good numerical efficiency so that the method can be useful for formulating dimensioning problems for large-scale networks. Numerical solution values from the proposed analysis method compare well with results from a discrete-event simulation of an optical burst switch

    Core noise measurements on a YF-102 turbofan engine

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    Core noise from a YF-102 high bypass ratio turbofan engine was investigated through the use of simultaneous measurements of internal fluctuating pressures and far field noise. Acoustic waveguide probes, located in the engine at the compressor exit, in the combustor, at the turbine exit, and in the core nozzle, were employed to measure internal fluctuating pressures. Spectra showed that the internal signals were free of tones, except at high frequency where machinery noise was present. Data obtained over a wide range of engine conditions suggest that below 60% of maximum fan speed the low frequency core noise contributes significantly to the far field noise

    Cognition and Economic Outcomes in the Health and Retirement Survey

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    Dimensions of cognitive skills are potentially important but often neglected determinants of the central economic outcomes that shape overall well-being over the life course. There exists enormous variation among households in their rates of wealth accumulation, their holdings of financial assets, and the relative risk in their chosen asset portfolios that have proven difficult to explain by conventional demographic factors, the amount of bequests they receive or anticipating giving, and the level of economic resources of the household. These may be cognitively demanding decisions at any age but especially so at older ages. This research examines the association of cognitive skills with wealth, wealth growth, and wealth composition for people in their pre and post-retirement years.

    Bridging the second gap in translation: a case study of barriers and facilitators to implementing Patient-initiated Clinics into secondary care

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    Rationale: Patient-initiated Clinics (PIC) have been found to be safe and have patient and service benefits in terms of satisfaction and cost. This paper reports our experiences of implementing PIC and the practical challenges of translating research into practice.Methods: The Knowledge to Action framework was used to inform the design of implementation plans in three different departments in one secondary healthcare organisation. A focused ethnographic approach was utilised to collect data on barriers and facilitators to implementation which were analysed using iterative qualitative analytic techniques. The Promoting Action on Research Implementation in Health Services framework was used to develop the analysis and data presentation. Results: The success of implementation was mixed across the three departments. Despite evidence of effectiveness, contextual issues at a department level, such as empowered leadership and team members, trust in colleagues and patients and capacity to make changes, impacted on the progress of implementation. Discussion: Patient-initiated Clinics can offer a useful and feasible alternative for follow-up care of some groups of patients with long-term conditions in secondary care and can be implemented through strong leadership and teamwork and a positive attitude to change. Although Implementation Science as an emerging field offers useful tools and theoretical support, its complexity may create additional challenges to implementation of specific interventions and so further contribute to the second gap in translation

    A pilot study of megestrol acetate and ibuprofen in the treatment of cachexia in gastrointestinal cancer patients.

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    Advanced gastrointestinal cancer patients with weight loss and an acute-phase response (n = 15) were given megestrol acetate (480 mg day(-1)) and ibuprofen (1200 mg day(-1)) for 6 weeks. Overall, there was an increase in body weight (P = 0.01) and a reduction in C-reactive protein concentrations (P = 0.02), with no change in total body water (P = 0.24) over this period. This regimen may be an effective non-toxic treatment for cancer cachexia and is worthy of further study

    Oral health and pathology: a macrophage account.

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    Macrophages are present in healthy oral mucosa and their numbers increase dramatically during disease. They can exhibit a diverse range of phenotypes characterised as a functional spectrum from pro-inflammatory to anti-inflammatory (regulatory) subsets. This review illustrates the role of these subsets in the oral inflammatory disease lichen planus, and the immunosuppressive disease oral squamous cell carcinoma (SCC). We conclude that the role of macrophages in driving progression in oral disease identifies them as potential therapeutic targets for a range of oral pathologies

    Effect of suspension systems on the physiological and psychological responses to sub-maximal biking on simulated smooth and bumpy tracks

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    The aim of this study was to compare the physiological and psychological responses of cyclists riding on a hard tail bicycle and on a full suspension bicycle. Twenty males participated in two series of tests. A test rig held the front axle of the bicycle steady while the rear wheel rotated against a heavy roller with bumps (or no bumps) on its surface. In the first series of tests, eight participants (age 19 – 27 years, body mass 65 – 82 kg) were tested on both the full suspension and hard tail bicycles with and without bumps fitted to the roller. The second series of test repeated the bump tests with a further six participants (age 22 – 31 years, body mass 74 – 94 kg) and also involved an investigation of familiarization effects with the final six participants (age 21 – 30 years, body mass 64 – 80 kg). Heart rate, oxygen consumption (VO<sub>2</sub>), rating of perceived exertion (RPE) and comfort were recorded during 10 min sub-maximal tests. Combined data for the bumps tests show that the full suspension bicycle was significantly different (P < 0.001) from the hard tail bicycle on all four measures. Oxygen consumption, heart rate and RPE were lower on average by 8.7 (s = 3.6) ml · kg<sup>-1</sup> · min<sup>-1</sup>, 32.1 (s = 12.1) beats · min<sup>-1</sup> and 2.6 (s = 2.0) units, respectively. Comfort scores were higher (better) on average by 1.9 (s = 0.8) units. For the no bumps tests, the only statistically significant difference (P = 0.008) was in VO<sub>2</sub>, which was lower for the hard tail bicycle by 2.2 (s = 1.7) ml · kg-1 · min<sup>-1</sup>. The results indicate that the full suspension bicycle provides a physiological and psychological advantage over the hard tail bicycle during simulated sub-maximal exercise on bumps
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