10,655 research outputs found

    Thrice weekly nocturnal in-centre haemodiafiltration: a 2-year experience

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    Background: Adequate control of plasma phosphate without phosphate binders is difficult to achieve on a thrice-weekly haemodialysis schedule. The use of quotidian nocturnal dialysis is effective but not practical in the in-centre setting. This quality improvement project was set up as an exercise allowing the evaluation of small-solute clearance by combining convection with extended-hour dialysis in a thrice-weekly hospital setting. Methods: A single-centred, prospective analysis of patients' electronic records was performed from August 2012 to July 2014. The duration of haemodiafiltration was increased from a median of 4.5 to 8 h. Dialysis adequacy, biochemical parameters and medications were reviewed on a monthly basis. A reduction in plasma phosphate was anticipated, so all phosphate binders were stopped. Results: Since inception, 14 patients have participated with over 2,000 sessions of dialysis. The pre-dialysis phosphate level fell from a mean of 1.52 ± 0.4 to 1.06 ± 0.1 mmol/l (p < 0.05). The average binder intake of 3.26 ± 2.6 tablets was eliminated. A normal plasma phosphate range has been maintained with increased dietary phosphate intake and no requirement for intradialytic phosphate supplementation. Conclusion: Phosphate control can be achieved without the need for binders or supplementation on a thrice-weekly in-centre haemodiafiltration program

    Numerical Investigation of Installed Jet Noise Sensitivity to Lift and Wing/Engine Positioning

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.As the turbofan engines of modern transport aircraft have increasingly larger bypass ratios, by necessity to avoid longer undercarriage, the engine must be installed closer to the wing. This then has the potential of interaction between the jet flow and a deployed flap. This interaction can be an important noise source when the high-lift systems are deployed, as at approach and take-off. Investigating the parameters that have a strong influence on the installation noise penalty can help in identifying noise reduction measures. In this paper Wall-Modelled Large Eddy Simulations (WMLES), combined with the FfowcsWilliams and Hawkings (FW-H) sound extrapolation method, are performed to reproduce three experimental cases, with the aim of isolating the different contributions of flap angle and trailing-edge/jet-axis distance h. The first case (DOAK), consisting of a single jet installed near a horizontal flat plate, confirms the fundamental mechanisms of jet-surface interaction and jet-surface reflection in the absence of lift. The second case (DLR-F16), with a coaxial jet installed under a high-lift wing, reveals the trailing-edge/jet-axis distance h as the dominant parameter, with a possible influence of the flap angle at low frequencies. The third case (SYMPHONY) is used to study the interaction of a coaxial jet with a full aircraft geometry using Fourier decomposition of the pressure near-field to analyse the effects on sound sources and radiation

    Mechanical Evidence of the Orbital Angular Momentum to Energy Ratio of Vortex Beams

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    We measure, in a single experiment, both the radiation pressure and the torque due to a wide variety of propagating acoustic vortex beams. The results validate, for the first time directly, the theoretically predicted ratio of the orbital angular momentum to linear momentum in a propagating beam. We experimentally determine this ratio using simultaneous measurements of both the levitation force and the torque on an acoustic absorber exerted by a broad range of helical ultrasonic beams produced by a 1000-element matrix transducer array. In general, beams with helical phase fronts have been shown to contain orbital angular momentum as the result of the azimuthal component of the Poynting vector around the propagation axis. Theory predicts that for both optical and acoustic helical beams the ratio of the angular momentum current of the beam to the power should be given by the ratio of the beam’s topological charge to its angular frequency. This direct experimental observation that the ratio of the torque to power does convincingly match the expected value (given by the topological charge to angular frequency ratio of the beam) is a fundamental result

    Telehealth: acceptability, clinical interventions and quality of life in peritoneal dialysis

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    Introduction: Telehealth technologies are being widely adopted across the globe for management of long-term conditions. There are limited data on its use, effectiveness and patient experience in end-stage renal disease. The aim of this pilot project was to explore patient acceptability of technology and evaluate its effect on clinical interventions and quality of life in patients undergoing peritoneal dialysis. Methods: Peritoneal dialysis patients were provided with computer tablets (PODs). PODs contained a knowledge database with treatment- and symptom-based questionnaires that generated alerts for the clinical team. Alerts were reviewed daily and followed up by a telephone call or clinic visit. Interventions were at the discretion of clinicians. Data were recorded prospectively and quality of life and Quebec User Evaluation of Satisfaction with assistive Technology questionnaires evaluated at the start and end of the programme. Results: In all, 22 patients have participated over 15 months. The mean age was 61.6 years and PODs were utilised for an average of 341.9 days with 59.1% choosing to continue beyond the study period. We received a total of 1195 alerts with an average of 2.6 alerts per day. A total of 36 admissions were avoided and patients supported to self-manage on 154 occasions. Quebec User Evaluation of Satisfaction with assistive Technology scores remained high throughout the programme although no improvement in quality of life was seen. Discussion: Telehealth is useful to monitor patients with renal failure on peritoneal dialysis. It is acceptable across age groups and provides an additional resource for patients to self-manage. Satisfaction scores and retention rates suggest a high level of acceptability

    Effect of continuous gamma-ray exposure on performance of learned tasks and effect of subsequent fractionated exposures on blood-forming tissue

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    Sixteen monkeys trained to perform continuous and discrete-avoidance and fixed-ratio tasks with visual and auditory cues were performance-tested before, during, and after 10-day gamma-ray exposures totaling 0, 500, 750, and 1000 rads. Approximately 14 months after the performance-test exposures, surviving animals were exposed to 100-rad gamma-ray fractions at 56-day intervals to observe injury and recovery patterns of blood-forming tissues. The fixed-ratio, food-reward task performance showed a transient decline in all dose groups within 24 hours of the start of gamma-ray exposure, followed by recovery to normal food-consumption levels within 48 to 72 hours. Avoidance tasks were performed successfully by all groups during the 10-day exposure, but reaction times of the two higher dose-rate groups in which animals received 3 and 4 rads per hour or total doses of 750 and 1000 rads, respectively, were somewhat slower

    Multidimensional collaboration; reflections on action research in a clinical context

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    This paper reflects on the challenges and benefits of multidimensional collaboration in an action research study to evaluate and improve preoperative education for patients awaiting colorectal surgery. Three cycles of planning, acting,observing and reflecting were designed to evaluate practice and implement change in this interactive setting, calling for specific and distinct collaborations. Data collection includes: observing educational interactions; administering patient evaluation questionnaires; interviewing healthcare staff, patients and carers; patient and carer focus groups; and examining written and audiovisual educational materials. The study revolves around and depends on multi-dimensional collaborations. Reflecting on these collaborations highlights the diversity of perspectives held by all those engaged in the study and enhances the action research lessons. Successfully maintaining the collaborations recognises the need for negotiation, inclusivity, comprehension, brokerage,and problem-solving. Managing the potential tensions is crucial to the successful implementation of changes introduced to practice and thus has important implications for patients’ well-being. This paper describes the experiences from an action research project involving new and specific collaborations, focusing on a particular healthcare setting. It exemplifies the challenges of the collaborative action research process and examines how both researchers and practitioners might reflect on the translation of theory into educational practices within a hospital colorectal department. Despite its context-specific features, the reflections on the types of challenges faced and lessons learned provide implications for action researchers in diverse healthcare settings across the world

    Genome sequence of the Chlamydophila abortus variant strain LLG

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    Chlamydophila abortus is a common cause of ruminant abortion. Here we report the genome sequence of strain LLG, which differs genotypically and phenotypically from the wild-type strain S26/3. Genome sequencing revealed differences between LLG and S26/3 to occur in pseudogene content, in transmembrane head/inc family proteins, and in biotin biosynthesis genes

    High Spatial Resolution Thermal-Infrared Spectroscopy with ALES: Resolved Spectra of the Benchmark Brown Dwarf Binary HD 130948BC

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    We present 2.9-4.1 micron integral field spectroscopy of the L4+L4 brown dwarf binary HD 130948BC, obtained with the Arizona Lenslets for Exoplanet Spectroscopy (ALES) mode of the Large Binocular Telescope Interferometer (LBTI). The HD 130948 system is a hierarchical triple system, in which the G2V primary is joined by two co-orbiting brown dwarfs. By combining the age of the system with the dynamical masses and luminosities of the substellar companions, we can test evolutionary models of cool brown dwarfs and extra-solar giant planets. Previous near-infrared studies suggest a disagreement between HD 130948BC luminosities and those derived from evolutionary models. We obtained spatially-resolved, low-resolution (R~20) L-band spectra of HD 130948B and C to extend the wavelength coverage into the thermal infrared. Jointly using JHK photometry and ALES L-band spectra for HD 130948BC, we derive atmospheric parameters that are consistent with parameters derived from evolutionary models. We leverage the consistency of these atmospheric quantities to favor a younger age (0.50 \pm 0.07 Gyr) of the system compared to the older age (0.79 \pm 0.22 Gyr) determined with gyrochronology in order to address the luminosity discrepancy.Comment: 17 pages, 9 figures, Accepted to Ap

    Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer

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    The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 μ\mum). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feedforward approach to stabilize the path length fluctuations seen by the LBTI nuller.Comment: SPIE conference proceeding

    Video recording true single-photon double-slit interference

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    As normally used, no commercially available camera has a low-enough dark noise to directly produce video recordings of double-slit interference at the photon-by-photon level, because readout noise significantly contaminates or overwhelms the signal. In this work, noise levels are significantly reduced by turning on the camera only when the presence of a photon has been heralded by the arrival, at an independent detector, of a time-correlated photon produced via parametric down-conversion. This triggering scheme provides the improvement required for direct video imaging of Young's double-slit experiment with single photons, allowing clarified versions of this foundational demonstration. Further, we introduce variations on this experiment aimed at promoting discussion of the role spatial coherence plays in such a measurement. We also emphasize complementary aspects of single-photon measurement, where imaging yields (transverse) position information, while diffraction yields the transverse momentum, and highlight the roles of transverse position and momentum correlations between down-converted photons, including examples of "ghost" imaging and diffraction. The videos can be accessed at http://sun.iwu.edu/~gspaldin/SinglePhotonVideos.html online.Comment: 7 pages, 8 figure
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