1,700 research outputs found

    Fluid machines: Expanding the limits, past and future

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    During the 40 yr period from 1940 to 1980, the capabilities and operating limits of fluid machines were greatly extended. This was due to a research program, carried out to meet the needs of aerospace programs. Some of the events are reviewed. Overall advancements of all machinery components are discussed followed by a detailed examination of technology advancements in axial compressors and pumps. Future technology needs are suggested

    Anticoagulants for acute ischaemic stroke

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    Peer reviewedPublisher PD

    The great outdoors: how a green exercise environment can benefit all

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    The studies of human and environment interactions usually consider the extremes of environment on individuals or how humans affect the environment. It is well known that physical activity improves both physiological and psychological well-being, but further evidence is required to ascertain how different environments influence and shape health. This review considers the declining levels of physical activity, particularly in the Western world, and how the environment may help motivate and facilitate physical activity. It also addresses the additional physiological and mental health benefits that appear to occur when exercise is performed in an outdoor environment. However, people's connectedness to nature appears to be changing and this has important implications as to how humans are now interacting with nature. Barriers exist, and it is important that these are considered when discussing how to make exercise in the outdoors accessible and beneficial for all. The synergistic combination of exercise and exposure to nature and thus the 'great outdoors' could be used as a powerful tool to help fight the growing incidence of both physical inactivity and non-communicable disease. © 2013 Gladwell et al.; licensee BioMed Central Ltd

    Off-design correlation for losses due to part-span dampers on transonic rotors

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    Experimental data from 10 transonic fan rotors were used to correlate losses created by part-span dampers located near the midchord position on the rotor blades. The design tip speed of these rotors varied from 419 to 425 m/sec, and the design pressure ratio varied from 1.6 to 2.0. Additional loss caused by the dampers for operating conditions between 50 and 100 percent of design speed were correlated with relevant aerodynamic and geometric parameters. The resulting correlation predicts the variation of total-pressure-loss coefficient in the damper region to a good approximation

    Data summary and computer program for axial-flow pump rotor performance

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    Assembly of noncavitating blade element performance data for axial-flow pump rotor configurations has been collected and organized. Program facilitates handling large amounts of experimental data involved and may be used as data reduction program to process flow and performance measurements from other axial-flow pump configurations

    Creating adaptive and individual personalities in many characters without hand crafting behaviours

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    Believable characters significantly increase the immersion of users or players in interactive applications. A key component of believable characters is their personality, which has previously been implemented statically using the time consuming task of hand-crafting individuality for each character. Often personality has been modeled based on theories that assume behavior is the same regardless of situation and environment. This paper presents a simple affective and cognitive framework for interactive entertainment characters that allows adaptation of behavior based on the environment and emotions. Different personalities are reflected in behavior preferences which are generated based on individual experience. An initial version of the framework has been implemented in a simple scenario to explore which parameters have the greatest effect on agent diversity

    Immunoprophylaxis against respiratory syncytial virus (RSV) with palivizumab in children: a systematic review and economic evaluation

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    Objectives: To systematically review the effectiveness and cost-effectiveness of palivizumab for the prevention of respiratory syncytial virus (RSV) in children and examine prognostic factors to determine whether subgroups can be identified with important differences in cost-effectiveness. Data sources: Bibliographic databases were searched from inception to March 2007 for literature on the effectiveness and cost-effectiveness of prophylaxis with palivizumab. Review methods: The literature was systematically reviewed and current economic evaluations were analysed to identify which parameters were driving the different cost-effectiveness estimates. A probabilistic decision-analytical model was built to assess the cost-effectiveness of prophylaxis with palivizumab for children at risk of RSV infection and the parameters populated with the best estimates thought most applicable to the UK. We also constructed a new model, the Birmingham Economic Evaluation (BrumEE). Cost-effectiveness analyses were undertaken from both NHS and societal perspectives. Results: Two randomised controlled trials (RCTs) were identified. Prophylaxis with palivizumab for preterm infants without chronic lung disease (CLD) or children with CLD resulted in a 55% reduction in RSV hospital admission: 4.8% (48/1002) in the palivizumab group and 10.6% (53/500) in the no prophylaxis group (p=0.0004). Prophylaxis with palivizumab was associated with a 45% reduction in hospitalisation rate RSV among children with coronary heart disease (CHD). Hospitalisation rates for RSV were 5.3% (34/639) in the palivizumab group and 9.7% (63/648) in the no prophylaxis group (p=0.003). Of existing economic evaluations, 3 systematic reviews and 18 primary studies were identified. All the systematic reviews concluded that the potential costs of palivizumab were far in excess of any potential savings achieved by decreasing hospital admission rates, and that the use of palivizumab was unlikely to be cost-effective in all children for whom it is recommended, but that its continued use for particularly high-risk children may be justified. The incremental cost-effectiveness ratios (ICERs) of the primary studies varied 17-fold for life-years gained (LYG), from £25,800/ LYG to £404,900/LYG, and several hundred-fold for quality-adjusted life years (QALYs), from £3200/QALY to £1,489,700/QALY for preterm infants without CLD or children with CLD. For children with CHD, the ICER varied from £5300/LYG to £7900/LYG and from £7500/ QALY to £68,700/QALY. An analysis of what led to the discrepant ICERs showed that the assumed mortality rate for RSV infection was the most important driver. The results of the BrumEE confirm that palivizumab does not reach conventional levels of cost-effectiveness in any of the licensed indications if used for all eligible children. Conclusions: Prophylaxis with palivizumab is clinically effective for the reducing the risk of serious lower respiratory tract infection caused by RSV infection and requiring hospitalisation in high-risk children, but if used unselectively in the licensed population, the ICER is double that considered to represent good value for money in the UK. The BrumEE shows that prophylaxis with palivizumab may be cost-effective (based on a threshold of £30,000/QALY) for children with CLD when the children have two or more additional risk factors. Future research should initially focus on reviewing systematically the major uncertainties for patient subgroups with CLD and CHD and then on primary research to address the important uncertainties that remain

    Brillouin scattering studies in Fe3_3O4_4 across the Verwey transition

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    Brillouin scattering studies have been carried out on high quality single crystals of Fe3_3O4_4 with [100] and [110] faces in the temperature range of 300 to 30 K. The room temperature spectrum shows a surface Rayleigh wave (SRW) mode at 8 GHz and a longitudinal acoustic (LA) mode at 60 GHz. The SRW mode frequency shows a minimum at the Verwey transition temperature TVT_V of 123 K. The softening of the SRW mode frequency from about 250 K to TVT_V can be quantitatively understood as a result of a decrease in the shear elastic constant C44_{44}, arising from the coupling of shear strain to charge fluctuations. On the other hand, the LA mode frequency does not show any significant change around TVT_V, but shows a large change in its intensity. The latter shows a maximum at around 120 K in the cooling run and at 165 K in the heating run, exhibiting a large hysteresis of 45 K. This significant change in intensity may be related to the presence of stress-induced ordering of Fe3+^{3+} and Fe2+^{2+} at the octahedral sites, as well as to stress-induced domain wall motion.Comment: 14 pages, 3 figures, accepted in Physical Review B 200

    Birmingham’s Eastside story: making steps towards sustainability?

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    Sustainability has come to play a dominant discursive role in the UK planning system, particularly relating to urban regeneration. The purpose of this paper is to evaluate the role that sustainability plays in a major regeneration programme, known as Eastside, currently underway in Birmingham, the UK. That this £6 billion redevelopment is now widely talked about by such key players as Birmingham City Council and the Regional Development Agency, Advantage West Midlands, as having a central sustainability agenda points to the growing importance of the ideal of sustainability in planning and regeneration agendas. In this paper, we investigate in detail how and why sustainability has become part of the planning discourse for Eastside and critically evaluate what impact, if any, this is having on public policy decision-making

    Responses of male Greater Prairie-Chickens to wind energy development

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    Citation: Winder, V. L., Gregory, A. J., McNew, L. B., & Sandercock, B. K. (2015). Responses of male Greater Prairie-Chickens to wind energy development. Condor, 117(2), 284-296. doi:10.1650/condor-14-98.1Renewable energy resources have received increased attention because of impacts of fossil fuels on global climate change. In Kansas, USA, optimal sites for wind energy development often overlap with preferred habitats of the Greater Prairie-Chicken (Tympanuchus cupido), a lek-mating prairie grouse of conservation concern. We tested for potential effects of energy development on male Greater Prairie-Chickens in north-central Kansas. We captured males at 23 leks located 0.04 to 28 km from wind turbines during a 2-yr preconstruction period (2007-2008) and a 3-yr postconstruction period (2009-2011). First, we tested for effects of proximity to turbines, habitat, and lek size on annual probability of lek persistence and changes in male numbers. We predicted that energy development might result in behavioral avoidance of areas close to turbines, resulting in increased rates of lek abandonment and fewer males attending surviving leks. We found that distance to turbine had a negative effect on lek persistence for leks,8 km from turbines during the postconstruction period, supporting the 8-km buffer zone recommended by the U.S. Fish and Wildlife Service as an offset for wind energy projects. Additionally, lek persistence was positively related to number of males counted at a lek and with grassland cover surrounding the lek. Second, we tested for effects of wind energy development on male body mass. We predicted that degraded habitat conditions might result in decreased body mass for males attending leks near turbines during the postconstruction period. Male body mass was similar to 2% lower during the postconstruction period, but distance to turbine did not affect body mass. Additional study is needed to determine whether short-term effects of turbines on lek persistence influence population viability of Greater Prairie-Chickens
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