972 research outputs found

    Space shuttle: Verification of transition reentry corridor at high angles of attack and determination of transition aerodynamic characteristics and subsonic aerodynamic characteristics at low angles of attack for the Boeing H-32 booster

    Get PDF
    Experimental aerodynamic investigations were made in a transonic wind tunnel on a 1/150-scale model of the Boeing H-32 space shuttle booster configuration. The purpose of the test was: (1) to verify the transonic reentry corridor at high angles of attack; (2) to determine the transonic aerodynamic characteristics; and (3) to determine the subsonic aerodynamic characteristics at low angles of attack. Test variables included configuration buildup, horizontal stabilizer settings of 0 and -20 deg, elevator deflections of 0 and -30 deg, and wing spoiler settings of 60 deg

    Australian GP attitudes to clinical practice guidelines and some implications for translating osteoarthritis care into practice

    Get PDF
    Abstract Clinical practice guidelines (CPGs) have been shown to improve processes of care and health outcomes, but there is often a discrepancy between recommendations for care and clinical practice. We sought to explore general practitioner attitudes toward CPGs, in general and specifically for osteoarthritis (OA) with the implications for translating OA care into practice. A self-administered questionnaire was conducted in January 2013 of a sample of 228 GPs in New South Wales and South Australia. Seventy-nine GPs returned questionnaires (response rate 35%). Nearly all GPs considered that CPGs support decision making in practice (94%) and medical education (92%). Very few respondents regarded CPGs as a threat to clinical autonomy, and most recognised that individual patient circumstances must be taken into account. Shorter CPG formats were preferred over longer and more comprehensive formats, with preferences being evenly divided amongst respondents for short, 2-3 page summaries, flowcharts or algorithms and single page checklists. GPs considered accessibility to CPGs to be important, and electronic formats were popular. Familiarity and use of The Royal Australian College of General Practitioners OA Guideline was poor with most respondents either not aware of it (30%: 95% CI 27% - 41%), had never used it (19%; 95% CI 12% - 29%), or rarely used it (34%; 95% CI 25% - 45%). If CPGs are to assist with the translation of evidence into practice, they must be easily accessible and in a format that encourages use. Key words: arthritis, primary care, evidence-based medicine, decision making Summary statement What is known about the topic? • Clinical practice guidelines (CPGs) can improve processes of care and health outcomes, however, there is often a gap between evidence-based recommendations for care and clinical practice. What does this paper add? • A better understanding of GP attitudes toward CPGs helps to explain potential barriers to the uptake of evidence-based practice and provides guidance on remedial action that may lead to better health outcomes.a National Health and Medical Research Council Program Grant (Australia, no.568612

    Crisis management during anaesthesia: problems associated with drug administration during anaesthesia

    Get PDF
    © 2005 BMJ Publishing Group Ltd.BACKGROUND: Modern anaesthetic practice relies upon the administration of a wide range of potent drugs given by a variety of routes, at times in haste or under conditions of stress. Problems associated with drug administration make up the largest group of incidents reported during anaesthesia, with outcomes including major morbidity and death. It was decided to examine the role of a structured approach to the diagnosis and management of drug problems under anaesthesia. OBJECTIVES: To examine the role of a previously described core algorithm "COVER ABCD–A SWIFT CHECK", supplemented by a specific sub-algorithm for drug problems, in the detection and management of drug problems occurring in association with anaesthesia. METHODS: The potential performance of this structured approach for the relevant incidents among the first 4000 incidents reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual performances as reported by the anaesthetists involved. RESULTS: Among the first 4000 reports received by AIMS there were 1199 reports which detailed 1361 incidents involving the use of drugs. Contributing factors named included errors of judgement (20%), lack of attention (17%), and drugs deemed to have been given in haste. Major morbidity or prolonged stay ensued in over one quarter of reports and 15 patients (1.25%) died. Drug overdose, side effects, and allergic reactions accounted for the majority of serious outcomes. CONCLUSION: It was judged that the use of the COVER–ABCD algorithm during the course of an anaesthetic, properly applied, would prevent many drug related incidents from occurring. The sub-algorithm presented here provides a systematic framework for detecting the causes of drug related incidents.A D Paix, M F Bullock, W B Runciman and J A Williamso

    Shape sensing of variable stiffness soft robots using electrical impedance tomography

    Get PDF
    Soft robotic systems offer benefits over traditional rigid systems through reduced contact trauma with soft tissues and by enabling access through tortuous paths in minimally invasive surgery. However, the inherent deformability of soft robots places both a greater onus on accurate modelling of their shape, and greater challenges in realising intraoperative shape sensing. Herein we present a proprioceptive (self-sensing) soft actuator, with an electrically conductive working fluid. Electrical impedance measurements from up to six electrodes enabled tomographic reconstructions using Electrical Impedance Tomography (EIT). A new Frequency Division Multiplexed (FDM) EIT system was developed capable of measurements of 66 dB SNR with 20 ms temporal resolution. The concept was examined in two two-degree-of-freedom designs: a hydraulic hinged actuator and a pneumatic finger actuator with hydraulic beams. Both cases demonstrated that impedance measurements could be used to infer shape changes, and EIT images reconstructed during actuation showed distinct patterns with respect to each degree of freedom (DOF). Whilst there was some mechanical hysteresis observed, the repeatability of the measurements and resultant images was high. The results show the potential of FDM-EIT as a low-cost, low profile shape sensor in soft robots

    LaryngoTORS: a novel cable-driven parallel robotic system for transoral laser phonosurgery

    Get PDF
    Transoral laser phonosurgery is a commonly used surgical procedure in which a laser beam is used to perform incision, ablation or photocoagulation of laryngeal tissues. Two techniques are commonly practiced: free beam and fiber delivery. For free beam delivery, a laser scanner is integrated into a surgical microscope to provide an accurate laser scanning pattern. This approach can only be used under direct line of sight, which may cause increased postoperative pain to the patient and injury, is uncomfortable for the surgeon during prolonged operations, the manipulability is poor and extensive training is required. In contrast, in the fiber delivery technique, a flexible fiber is used to transmit the laser beam and therefore does not require direct line of sight. However, this can only achieve manual level accuracy, repeatability and velocity, and does not allow for pattern scanning. Robotic systems have been developed to overcome the limitations of both techniques. However, these systems offer limited workspace and degrees-of-freedom (DoF), limiting their clinical applicability. This work presents the LaryngoTORS, a robotic system that aims at overcoming the limitations of the two techniques, by using a cable-driven parallel mechanism (CDPM) attached at the end of a curved laryngeal blade for controlling the end tip of the laser fiber. The system allows autonomous generation of scanning patterns or user driven freepath scanning. Path scan validation demonstrated errors as low as 0.054±0.028 mm and high repeatability of 0.027±0.020 mm (6×2 mm arc line). Ex vivo tests on chicken tissue have been carried out. The results show the ability of the system to overcome limitations of current methods with high accuracy and repeatability using the superior fiber delivery approach

    Living apart, losing sympathy? How neighbourhood context affects attitudes to redistribution and to welfare recipients

    Get PDF
    Rising levels of income inequality have been directly linked to rising levels of spatial segregation. In this paper, we explore whether rising segregation may in turn erode support for the redistributive policies of the welfare state, further increasing levels of inequality – a form of positive feedback. The role of the neighbourhood has been neglected in attitudes research but, building on both political geography and ‘neighbourhood effects’ literatures, we theorise that neighbourhood context may shape attitudes through the transmission of attitudes directly and through the accumulation of relevant knowledge. We test this through multilevel modelling of data from England on individual attitudes to redistribution in general and to welfare benefit recipients in particular. We show that the individual factors shaping these attitudes are quite different and that the influence of neighbourhood context also varies as a result. The findings support the idea that neighbourhood context shapes attitudes, with the knowledge accumulation mechanism likely to be the more important. Rising spatial segregation would appear to erode support for redistribution but to increase support for welfare recipients – at least in a context where the dominant media discourse presents such a stigmatising image of those on welfare benefits

    Lumen shape reconstruction using a soft robotic balloon catheter and electrical impedance tomography

    Get PDF
    Incorrectly sized balloon catheters can lead to increased post-surgical complications, yet even with preoperative imaging, correct selection remains a challenge. With limited feedback during surgery, it is difficult to verify correct deployment. We propose the use of integrated impedance measurements and Electrical Impedance Tomography (EIT) imaging to assess the deformation of the balloon and determine the size and shape of the surrounding lumen. Previous work using single impedance measurements, or pressure data and analytical models, whilst demonstrating high sizing accuracy, have assumed a circular cross section. Here we extend these methods by adding a multitude of electrodes to detect elliptical and occluded lumen and obtain EIT images to localise deformations. Using a 14 Fr (5.3 mm) catheter as an example, numerical simulations were performed to find the optimal electrode configuration of two rings of 8 electrodes spaced 10 mm apart. The simulations predicted that the maximum detectable aspect ratio decreased from 0.9 for a 14mm balloon to 0.5 at 30mm. The sizing and ellipticity detection results were verified experimentally. A prototype robotic balloon catheter was constructed to automatically inflate a compliant balloon while simultaneously recording EIT and pressure data. Data were collected in experiments replicating stenotic vessels with an elliptical and asymmetrical profile, and the widening of a lumen during angioplasty. After calibration, the system was able to correctly localise the occlusion and detect aspect ratios of 0.75. EIT images further localised the occlusion and visualised the dilation of the lumen during balloon inflation

    Measuring change in vulnerable adolescents: Findings from a peer education evaluation in South Africa

    Get PDF
    Introduction: In the context of poverty and HIV and AIDS, peer education is thought to be capable of providing vulnerable youth with psychosocial support as well as information and decision-making skills otherwise limited by scarce social and material resources. As a preventative education intervention method, peer education is a strategy aimed at norms and peer group influences that affect health behaviours and attitudes. However, too few evaluations of peer-led programmes are available,and they frequently fail to reflect real differences between those who have been recipients of peer education and those who have not. This article reports on an evaluation of a pilot peer-led intervention, entitled Vhutshilo, implemented on principles agreed upon through a collaborative effort in South Africa by the Harvard School of Public Health and the Centre for theSupport of Peer Education (the Rutanang collaboration). Vhutshilo targeted vulnerable adolescents aged 14–16 years living in some of South Africa’s under-resourced communities. Methodology: The research design was a mixed-method (qualitative and quantitative), longitudinal, quasi-experimental evaluation. Tools used included a quantitative survey questionnaire (n ¼ 183) and semi-structured interviews (n ¼ 32) with beneficiaries of peer education. Surveys were administered twice forbeneficiaries of peer education (n ¼ 73), immediately after completion of the programme (post-test) and 4 months later (delayed post-test), and once for control group members (n ¼ 110). The three main  methodological limitations in this study were the use of a once-off control group assessment as the baseline for comparison, without a pre-test, due to timing and resource constraints; a small sample size (n ¼ 183), which reduced the statistical power of the evaluation; and the unavailability of existing tested survey questions to measure the impact of peer education and its role in behaviour change. Findings: This article reports on the difficulties of designing a comprehensive evaluation within time and financial constraints, critically evaluates survey design with multi-item indicators, and discusses six statistically significant changes observed in Vhutshilo participants out of a 92-point survey. Youth struggling with poor quality education and living in economically fraught contexts with little social support, nonetheless, showed evidence of having greater knowledge of support networks and an expanded emotional repertoire by the end of the Vhutshilo programme, and 4 months later. At both individual and group level, many with low socio-economic status showed great improvement with regard to programme indicator scores. Conclusion: For the poorest adolescents, especially those living in the rural parts of South Africa, peer education has the potential to change future orientation, attitudes and knowledge regarding HIV and AIDS, including an intolerance for multiple concurrent partnerships. When well organised and properly supported, peer education programmes (and the Vhutshilo curriculum, in particular) provide vulnerable youth with opportunities to develop  psychosocial skills and informational resources that contribute to the changing of norms, attitudes and behaviours. However, the article also flags the need for effective peer education evaluations that take into account limited financial resources and that possess tested indicators of programme effectiveness

    A Soft Inflatable Robot Driven by Hydraulic Folded Pouch Actuators for Minimally Invasive Surgery

    Get PDF
    This paper presents a soft, inflatable, cable-driven parallel robot (CDPR) for Minimally Invasive Surgery. The CDPR has 5 degrees of freedom and is driven by 6 cables and 6 hydraulic folded actuators. The actuator utilizes a folded chamber to pull a cable. The robot comprises a soft hexagonal variable-stiffness scaffold with a welded internal triangular support, which increases the stiffness of the robot when pressurized. The fabrication methodology is demonstrated in detail. A test platform is designed to obtain the characteristics of the folding actuator. The relationship between input liquid volume and actuator displacement can be predicted well by a geometry-based method. The displacement output of the actuator can reach 22 mm, which is nearly twice its length in its zero-volume folded state. Robot repeatability tests show mean and root mean square errors below 0.3 mm. The robot is made from plastic laminate sheets of thickness 120 μm and can deploy from 100 mm in length and 14 mm in diameter when folded, into an inflatable hollow hexagonal prism with 29 mm side length and 78 mm edge length. Deployment in a colon phantom is demonstrated and simulated surgery is conducted to validate the robot performance
    • …
    corecore