82 research outputs found

    System and method for improved rotor tip performance

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    The present invention discloses systems and methods for the performance enhancement of rotary wing aircraft through reduced torque, noise and vibration. In one embodiment, a system includes a sail having an aerodynamic shape positioned proximate to a tip of the rotor blade. An actuator may be configured to rotate the sail relative to the blade tip. a A control system receives information from a rotorcraft system and commands the actuator to rotate the sail to a predetermined favorable rotor blade operating condition. In another embodiment, a method includes configuring the rotorcraft in a selected flight condition, communicating input signals to a control system operable to position sails coupled to tips of blades of a rotor assembly, processing the input signals according to a constraint condition to generate sail positional information, and transferring the sail positional information to the sail

    System and method for improved rotor tip performance

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    Embodiments of systems and methods for enhancing the performance of rotary wing aircraft through reduced torque, noise and vibration are disclosed. In one embodiment, a method includes configuring the rotorcraft in a selected flight condition, communicating input signals to a control system operable to position sails coupled to tips of blades of a rotor assembly, processing the input signals according to a constraint condition to generate sail positional information, and transferring the sail positional information to the sail. Alternately, input signals may be communicated to a control system operable to position a plurality of sails, each sail having an aerodynamic shape and positioned proximate to a tip portion of the rotor blade. The input signals may be configured to rotate each sail about a longitudinal axis into a corresponding pitch angle independently of the other sails

    Associations of physical activity and quality of life in parapneumonic effusion patients

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    Introduction Little is known about activity behaviours and quality of life (QoL) of patients with parapneumonic pleural effusions (PPE) after hospital discharge. This study is a secondary analysis of a randomised trial (dexamethasone versus placebo) for hospitalised patients with PPE. We: 1) described the patients’ activity behaviour patterns and QoL measured at discharge and at 30 days post-discharge; and 2) examined the association between activity behaviours and QoL scores. Methods Activity behaviour (7-day accelerometry; Actigraph GT3X+) and QoL (Medical Outcomes Study Short-Form 36) were assessed. Repeated measures analysis of covariance controlling for baseline values and a series of linear regression models were undertaken. Results 36 out of 53 eligible participants completed accelerometry assessments. Despite modest increases in light physical activity (+7.5%) and some domains of QoL ( \u3e 2 points) from discharge to 30 days post-discharge, patients had persistently high levels of sedentary behaviour ( \u3e 65% of waking wear time) and poor QoL ( ⩽ 50 out of 100 points) irrespective of treatment group ( p=0.135–0.903). Increasing moderate-to-vigorous physical activity was associated with higher scores on most QoL domains ( p=0.006–0.037). Linear regression indicates that a clinically important difference of 5 points in physical composite QoL score can be achieved by reallocating 16.1 min·day−1 of sedentary time to moderate-to-vigorous physical activity. Conclusion Patients with PPE had low levels of physical activity and QoL at discharge and 30 days post-discharge irrespective of treatment. Moderate-to-vigorous physical activity participation was associated with higher QoL scores. Increasing moderate-to-vigorous physical activity following discharge from the hospital may be associated with improvements in QoL. © The authors 2023

    Results of the NFIRAOS RTC trade study

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    With two large deformable mirrors with a total of more than 7000 actuators that need to be driven from the measurements of six 60x60 LGS WFSs (total 1.23Mpixels) at 800Hz with a latency of less than one frame, NFIRAOS presents an interesting real-time computing challenge. This paper reports on a recent trade study to evaluate which current technology could meet this challenge, with the plan to select a baseline architecture by the beginning of NFIRAOS construction in 2014. We have evaluated a number of architectures, ranging from very specialized layouts with custom boards to more generic architectures made from commercial off-the-shelf units (CPUs with or without accelerator boards). For each architecture, we have found the most suitable algorithm, mapped it onto the hardware and evaluated the performance through benchmarking whenever possible. We have evaluated a large number of criteria, including cost, power consumption, reliability and flexibility, and proceeded with scoring each architecture based on these criteria. We have found that, with today’s technology, the NFIRAOS requirements are well within reach of off-the-shelf commercial hardware running a parallel implementation of the straightforward matrix-vector multiply (MVM) algorithm for wave-front reconstruction. Even accelerators such as GPUs and Xeon Phis are no longer necessary. Indeed, we have found that the entire NFIRAOS RTC can be handled by seven 2U high-end PC-servers using 10GbE connectivity. Accelerators are only required for the off-line process of updating the matrix control matrix every ~10s, as observing conditions change

    Impact Factor: outdated artefact or stepping-stone to journal certification?

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    A review of Garfield's journal impact factor and its specific implementation as the Thomson Reuters Impact Factor reveals several weaknesses in this commonly-used indicator of journal standing. Key limitations include the mismatch between citing and cited documents, the deceptive display of three decimals that belies the real precision, and the absence of confidence intervals. These are minor issues that are easily amended and should be corrected, but more substantive improvements are needed. There are indications that the scientific community seeks and needs better certification of journal procedures to improve the quality of published science. Comprehensive certification of editorial and review procedures could help ensure adequate procedures to detect duplicate and fraudulent submissions.Comment: 25 pages, 12 figures, 6 table

    A gender-sensitised weight-loss and healthy living program for men with overweight and obesity in Australian Football League settings (Aussie-FIT): A pilot randomised controlled trial

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    Background: Recent evidence shows that sport settings can act as a powerful draw to engage men in weight loss. The primary objective of this pilot study was to test feasibility of delivering and evaluating preliminary efficacy of Aussie-FIT, a weight loss program for overweight/obese men delivered in Australian Football League settings, in preparation for a future definitive trial. Methods and Findings: This 6-month pilot trial took place in Perth, Australia. Participants were overweight/obese (BMI > 28 kg/m2), middle-aged (35-65 years old) men. Participants were recruited in May 2018 and the intervention took place between June and December 2018. The intervention involved 12 weekly 90-minute face-to-face sessions, incorporating physical activity, nutrition, and behaviour change information and practical activities delivered by coaches at two clubs. Data were collected at baseline and immediately post-intervention. For trial feasibility purposes, 6-month follow-ups were completed. Outcomes were differences in weight loss (primary outcome), and recruitment and retention rates, self-reported measures (e.g., psychological well-being), device-measured physical activity, waist size, and blood pressure at 3-months. Within three days of advertising at each club, 426 men registered interest; 306 (72%) were eligible. Men were selected on first-come first-served basis (n = 130; M age = 45.8, SD = 8; M 17 BMI = 34.48 kg/m2, SD = 4.87) and randomised by a blinded researcher. Trial retention was 86% and 63% at 3- and 6-month follow-ups (respectively). No adverse events were reported. At 3 months, mean difference in weight between groups, adjusted for baseline weight and group, was 3.3kg (95% CI 1.9, 4.8) in favour of the intervention group (p < 0.001). The intervention group’s moderate-to-vigorous physical activity (MVPA) was higher than the control group by 8.54 mins/day (95% CI 1.37, 15.71, p = 0.02). MVPA among men attracted to Aussie-FIT was high at baseline (intervention arm 35.61 min/day, control arm 38.38 min/day), which may have limited the scope for improvement. Conclusions: Aussie-FIT was feasible to deliver; participants increased physical activity, decreased weight, and reported improvements in other outcomes. Issues with retention were a limitation of this trial. In a future, fully powered randomised controlled trial (RCT), retention could be improved by conducting assessments outside of holiday seasons

    Guidelines for the use of diagnostic imaging in musculoskeletal (MSK) pain conditions affecting the lower back, knee and shoulder: a scoping review

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    Musculoskeletal (MSK) pain is one of the most common reasons for primary care consultation, particularly pain in the lower back (LBP), knee, and shoulder. The use of diagnostic imaging for musculoskeletal pain is increasing but it is unclear whether this increase is justified based on clinical practice guideline (CPG) recommendations. Aim To identify and map the content of CPGs that inform the use of diagnostic imaging in those with non-traumatic LBP, knee, and shoulder pain in primary and intermediate care in the UK. Design and Setting A scoping review of CPGs. Methods This scoping review was conducted and is reported in accordance with PRISMA guidance. A broad search strategy included electronic searches of MEDLINE, CINAHL, PsychINFO and SPORTDiscus from 2009 to the 17th April 2019. This was conducted alongside a search of guideline repositories and was combined with a snowball search of Google, relevant professional bodies and use of social media. Results 31 relevant CPGs were included. Routine use of diagnostic imaging for those with non-traumatic LBP, knee or shoulder pain is generally discouraged in primary care or intermediate care. Diagnostic imaging should be reserved for when specific or serious pathology is suspected or where the person is not responding to initial non-surgical management and the imaging result is expected to change clinical management decisions. Conclusion Diagnostic imaging should not be routinely requested in primary or intermediate care for non-traumatic LBP, knee, or shoulder pain. CPGs do not justify the increasing imaging rates in the UK for musculoskeletal pain

    Whole shaft visibility and mechanical performance for active MR catheters using copper-nitinol braided polymer tubes

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    <p>Abstract</p> <p>Background</p> <p>Catheter visualization and tracking remains a challenge in interventional MR.</p> <p>Active guidewires can be made conspicuous in "profile" along their whole shaft exploiting metallic core wire and hypotube components that are intrinsic to their mechanical performance. Polymer-based catheters, on the other hand, offer no conductive medium to carry radio frequency waves. We developed a new "active" catheter design for interventional MR with mechanical performance resembling braided X-ray devices. Our 75 cm long hybrid catheter shaft incorporates a wire lattice in a polymer matrix, and contains three distal loop coils in a flexible and torquable 7Fr device. We explored the impact of braid material designs on radiofrequency and mechanical performance.</p> <p>Results</p> <p>The incorporation of copper wire into in a superelastic nitinol braided loopless antenna allowed good visualization of the whole shaft (70 cm) <it>in vitro </it>and <it>in vivo </it>in swine during real-time MR with 1.5 T scanner. Additional distal tip coils enhanced tip visibility. Increasing the copper:nitinol ratio in braiding configurations improved flexibility at the expense of torquability. We found a 16-wire braid of 1:1 copper:nitinol to have the optimum balance of mechanical (trackability, flexibility, torquability) and antenna (signal attenuation) properties. With this configuration, the temperature increase remained less than 2°C during real-time MR within 10 cm horizontal from the isocenter. The design was conspicuous <it>in vitro </it>and <it>in vivo</it>.</p> <p>Conclusion</p> <p>We have engineered a new loopless antenna configuration that imparts interventional MR catheters with satisfactory mechanical and imaging characteristics. This compact loopless antenna design can be generalized to visualize the whole shaft of any general-purpose polymer catheter to perform safe interventional procedures.</p
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