873 research outputs found

    Simulation evaluation of a low-altitude helicopter flight guidance system adapted for a helmet-mounted display

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    A computer aiding concept for low-altitude helicopter flight was developed and evaluated in a real-time piloted simulation. The concept included an optimal control trajectory-generation algorithm based upon dynamic programming and a helmet-mounted display (HMD) presentation of a pathway-in-the-sky, a phantom aircraft, and flight-path vector/predictor guidance symbology. The trajectory-generation algorithm uses knowledge of the global mission requirements, a digital terrain map, aircraft performance capabilities, and advanced navigation information to determine a trajectory between mission way points that seeks valleys to minimize threat exposure. The pilot evaluation was conducted at NASA ARC moving base Vertical Motion Simulator (VMS) by pilots representing NASA, the U.S. Army, the Air Force, and the helicopter industry. The pilots manually tracked the trajectory generated by the algorithm utilizing the HMD symbology. The pilots were able to satisfactorily perform the tracking tasks while maintaining a high degree of awareness of the outside world

    The Effect of Instrument Assisted Soft Tissue Mobilization on Improving Joint Range of Motion in Active Individuals: A Critically Appraised Topic

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    CLINICAL SCENARIO In all activities that require physical movement, whether in athletics or in other daily tasks, it is important for joints to have adequate range of motion and flexibility. Soft tissue restrictions are very common pathologies in healthcare. Although a decrease in myofascial range of motion can arise from a variety of reasons such as biomechanical deformities, autoimmune diseases, or age, it is often caused by overtraining or musculoskeletal injuries in active populations. Instrument assisted soft tissue mobilization techniques are gaining popularity to assist in treating various soft tissue injuries and musculoskeletal pathologies. The belief is that by applying a stimulus to the soft tissue around a joint, it will increase the number of fibroblasts, through localized inflammation, and result in a realignment of collagen fibers2. While some studies have shown positive outcomes of instrument assisted soft tissue mobilization (IASTM), there has been limited evidence to determine the efficacy of this modality in improving joint range of motion (ROM)

    Bostonia. Volume 3

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    Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

    Communicating the relevance of paleo research in the current societal environment

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    It is not an easy task for paleoscientists to communicate the relevance of their research to policy makers and funders. However, an increase in catastrophic environmental calamities related to climate change (e.g. landslide, droughts, flooding) demands a response both in terms of policy-making and future governmental decisions. Often, climate change in the recent past was linked to major shifts in human behavior, which masks the relative contribution of humans and nature. For example, the 4.2 ka BP aridification event was so severe that it may have triggered the collapse of several large civilizations (the Old Kingdom in Egypt and the Akkadian Empire in Mesopotamia; Gibbons 1993). Compilations of long-term records of past variability can help reduce the uncertainties on past, present and future climate changes, and thus support informed societal decisions. Therefore, policymakers should (and some may argue, must) consider the long-term perspective provided by paleoscience research

    E-learning as a tool for knowledge transfer through traditional and independent study at two UK higher educational institutes: a case study

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    Much has been made of the advances in computer aided learning activities. Websites, virtual campus, the increased use of Web CT and chat rooms and further advances in the use of WebCT are becoming more commonplace in UK universities. This paper looks for ways of changing higher education students’ perception of the usefulness of recommended internet web sites for learning purposes, with the intention of increasing the usage rate of recommended module web-sites. The change could represent an adaptation of the existing, well-known technology to change students’ perception regarding its potentially formative role. Subsequently, the outcomes from this preliminary research could be used in order to enhance the quality of the Internet use for teaching and learning purposes

    A 10-year experience of infection following carotid endarterectomy with patch angioplasty

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    ObjectiveAlthough infection following carotid endarterectomy is rare, consequences of this seldom seen complication can be devastating. Polyester, polytetrafluoroethylene (PTFE), and vein patches have all been used by many institutions for patch angioplasty, each with reported cases of infection following surgery. Our institution has preferentially used PTFE for the majority of cases, and here, we report our experience with postoperative infection following endarterectomy over the last decade.MethodsFrom January 2000 through July 2009, we treated infections following carotid endarterectomy in 25 patients.ResultsOf the 25 patients undergoing treatment for postoperative infection, 21 had PTFE patches placed during the initial surgery. The remaining four consisted of two polyester patches and two bovine pericardial patches. Twenty-three of the 25 initial endarterectomies were performed at our institution, and the other two were referrals. The majority of cases (56%) were due to gram-positive organisms, with only two cases being polymicrobial. The interval from the original surgery to clinical presentation ranged from 7 days to 85 months, with 20 patients (80%) presenting within 60 days of the first operation. Thirteen patients underwent incision and drainage with antibiotics, and 12 patients underwent definitive surgical treatment. Four received patch excision with vein patch angioplasty, four received patch excision with vein interposition, and four received sternocleidomastoid flaps. The 30-day stroke rate was 8%, and the freedom from recurrent infection was 100% at a mean follow-up of 32 months.ConclusionInfection following carotid endarterectomy occurs <1% of the time; however, the potential for morbidity is significant. Our results show that most infections following PTFE patch angioplasty occur in the early postoperative period (<60 days) and that simple drainage with antibiotics may be an adequate form of treatment in select cases

    Safe and just operating spaces for regional social-ecological systems

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    Humanity faces a major global challenge in achieving wellbeing for all, while simultaneously ensuring that the biophysical processes and ecosystem services that underpin wellbeing are exploited within scientifically informed boundaries of sustainability. We propose a framework for defining the safe and just operating space for humanity that integrates social wellbeing into the original planetary boundaries concept (Rockström et al., 2009a,b) for application at regional scales. We argue that such a framework can: (1) increase the policy impact of the boundaries concept as most governance takes place at the regional rather than planetary scale; (2) contribute to the understanding and dissemination of complexity thinking throughout governance and policy-making; (3) act as a powerful metaphor and communication tool for regional equity and sustainability. We demonstrate the approach in two rural Chinese localities where we define the safe and just operating space that lies between an environmental ceiling and a social foundation from analysis of time series drawn from monitored and palaeoecological data, and from social survey statistics respectively. Agricultural intensification has led to poverty reduction, though not eradicated it, but at the expense of environmental degradation. Currently, the environmental ceiling is exceeded for degraded water quality at both localities even though the least well-met social standards are for available piped water and sanitation. The conjunction of these social needs and environmental constraints around the issue of water access and quality illustrates the broader value of the safe and just operating space approach for sustainable development

    Design and flight evaluation of an integrated navigation and near-terrain helicopter guidance system for night-time and adverse weather operations

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    NASA and the U.S. Army have designed, developed, and flight evaluated a Computer Aiding for Low Altitude Helicopter Flight (CALAHF) guidance system. This system provides guidance to the pilot for near terrain covert helicopter operations. It automates the processing of precision navigation information, helicopter mission requirements, and terrain flight guidance. The automation is presented to the pilot through symbology on a helmet-mounted display. The symbology is a 'pilot-centered' design which preserves pilot flexibility and authority over the CALAHF system's automation. An extensive flight evaluation of the system has been conducted using the U.S. Army's NUH-60 STAR (Systems Testbed for Avionics Research) research helicopter. The evaluations were flown over a multiwaypoint helicopter mission in rugged mountainous terrain, at terrain clearance altitudes from 300 to 125 ft and airspeeds from 40 to 110 knots. The results of these evaluations showed that the pilots could precisely follow the automation symbology while maintaining a high degree of situational awareness
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