2,779 research outputs found

    What could keep young people away from alcohol and cigarettes? Findings from the UK Household Longitudinal Study

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    BACKGROUND: Adolescents are vulnerable to risky behaviours that are likely to co-occur. We examined whether happiness, awareness of alcohol- or smoking-related harm or the size of friendship networks would be longitudinally associated with young people's risky behaviours. METHODS: We used available cases (N=1,729) from adolescents aged between 10 and 15 who participated in waves 2 and 3 of the UK Longitudinal Household Study that has annually collected population representative data from 40,000 UK households. The outcome variable was patterns of cigarette and alcohol use among adolescents (1= persistent non-use; 2= ex-use; 3= initiation; 4= persistent use) that we derived by tabulating current alcohol or cigarette use at waves 2 and 3. Explanatory variables were scores on participants' perception of overall happiness, awareness of harm due to alcohol and cigarette use, and supportive friendship network size, collected at wave 2. Covariates were participants' sex, age, base level of self-reported health status, reported religious affiliation, and household social position. All estimates were corrected for the complex survey design and non-response. Multinomial logistic regression was used to test assumed associations by taking persistent cigarette and alcohol use as the reference category. RESULTS: Findings showed higher happiness scores were longitudinally associated with adolescents' persistent non-use (RRR=1.06, 95% CI=1.01-1.13). Awareness of alcohol or cigarette use-related harm was longitudinally associated with persistent non-use (RRR=1.24, 95% CI 1.15-1.35) as well as initiation of alcohol or cigarette use (RRR=1.21, 95% CI=1.11-1.32). CONCLUSION: Joint interventions to promote happiness and harm awareness could help young adolescents from engaging with drinking alcohol or smoking cigarettes

    Using piloted simulation to measure pilot workload of landing a helicopter on a small ship

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    When conducting landings to a ship's deck in strong winds, helicopter pilot workload is often dominated by the turbulence within the ship's airwake. Previous studies have shown that larger ships create more aggressive airwakes and simulated flight trials had shown that it can be easier to land to a smaller ship than a large one. However, there are helicopter-enabled ships that are less than 100m in length and these will have significantly greater ship motion in rough seas than a large ship. The study reported in this paper has used a motion-base flight simulator to evaluate the pilot workload when landing to three geometrically similar ships of lengths 100m, 150m and 200m. Ship motion software has been used to create realistic deck displacements for sea states 4, 5 and 6, which are consistent with the increasing wind speed over the deck. It has been shown that the 100m ship was the most difficult to land to, with deck motion being the limiting factor. The next most difficult ship to land to was the 200m ship, with airwake turbulence being the limiting factor. The 150m ship generated the lowest pilot workload. The study has demonstrated that when ship motion is excessive, as it will be with small ships in rough seas, pilot workload will be dominated by deck motion during a landing task, but as the ship gets larger and more stable, airwake disturbances will dominate. It is clear from this study that realistic ship motion is essential when using piloted flight simulation to conduct simulated ship-helicopter operations

    The Development and Use of A Piloted Flight Simulation Environment for Rotary-Wing Operation to the Queen Elizabeth Class Aircraft Carriers

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    Flight simulation is being used to inform the First of Class Flight Trials for the UK’s new Queen Elizabeth Class (QEC) aircraft carriers. The carriers will operate with the Lockheed Martin F-35B Lightning II fighter aircraft, i.e. the Advanced Short Take-Off and Vertical Landing variant of the F-35. The rotary wing assets that are expected to operate with QEC include Merlin, Wildcat, Chinook and Apache helicopters. An F-35B flight simulator has been developed and is operated by BAE Systems at Warton Aerodrome. The University of Liverpool is supporting this project by using Computational Fluid Dynamics (CFD) to provide the unsteady air flow field that is required in a realistic flight simulation environment. This paper is concerned with a research project that is being conducted using the University’s research simulator, HELIFLIGHT-R, to create a simulation environment for helicopter operations to the QEC. The paper briefly describes how CFD has been used to model the unsteady airflow over the 280m long aircraft carrier and how this is used to create a realistic flight simulation environment. Results are presented from an initial simulation trial in which test pilots have used the HELIFLIGHT-R simulator to conduct simulated helicopter landings to two landing spots on the carrier, one in a disturbed air flow and the other in clean air. As expected, the landing to the spot in disturbed air flow requires a greater pilot workload, shows greater deviation in its positional accuracy and requires more control activity. This initial trial is the first of a planned series of simulated helicopter deck landings for different wind angles and magnitudes

    The Queen Elizabeth Class Aircraft Carriers: Airwake Modelling and Validation for ASTOVL Flight Simulation

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    This paper outlines progress towards the development of a high-fidelity piloted flight simulation environment for the UK’s Queen Elizabeth Class (QEC) aircraft carriers which are currently under construction. It is intended that flight simulation will be used to de-risk the clearance of the F-35B Lightning-II to the ship, helping to identify potential wind-speeds/directions requiring high pilot workload or control margin limitations prior to First of Class Flight Trials. Simulated helicopter launch & recovery trials are also planned for the future. The paper details the work that has been undertaken at the University of Liverpool to support this activity, and which draws upon Liverpool’s considerable research experience into simulated launch and recovery of maritime helicopters to single-spot combat ships. Predicting the unsteady air flow over and around the QEC is essential for the simulation environment; the very large and complex flow field has been modelled using Computational Fluid Dynamics (CFD) and will be incorporated into the flight simulators at the University of Liverpool and BAE Systems Warton for use in future piloted simulation trials. The challenges faced when developing airwake models for such a large ship are presented together with details of the experimental setup being prepared to validate the CFD predictions. Finally, the paper describes experimental results produced to date for CFD validation purposes and looks ahead to the piloted simulation trials of aircraft launch and recovery operations to the carrier

    The Development, Validation, and Integration of Aircraft Carrier Airwakes for Piloted Flight Simulation

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    This thesis reports on an investigation into the effects of ship airwake upon piloted aircraft operating to the United Kingdom’s newly commissioned Queen Elizabeth Class (QEC) aircraft carriers. Piloted flight simulation has been used to inform operation of aircraft to the ship, helping to identify potential wind-speeds/directions requiring high pilot workload prior to First of Class Flight Trials (FOCFT) aboard HMS Queen Elizabeth. The air flow over the QEC was generated using full-scale, time-accurate Computational Fluid Dynamics (CFD) at a range of wind azimuths, with the resultant airwakes incorporated into the flight simulators at both the University of Liverpool and BAE Systems Warton, enabling unsteady aerodynamic loads to be imposed upon rotary-wing and fixed-wing aircraft models, respectively. An additional CFD airwake was generated around a US Navy LHA helicopter carrier, and a comparison was made with real-world anemometer data in an attempt to validate the CFD method used for QEC. LHA at-sea measurements were found to be unreliable for CFD validation due to the inherent unpredictability of at-sea testing. As a result, an experimental validation experiment was recommended to validate the QEC CFD airwakes. A comparison was also made between LHA and QEC, with the twin-island QEC found to have increased turbulence gradient across the flight deck when compared with the single-island LHA. A description is given of the development of a novel Acoustic Doppler Velocimetry (ADV) experiment in a recirculating water channel, for which a 1:202 scale (1.4m) physical model of QEC was produced. To ensure spatial accuracy of ADV probe measurements during validation, an electronic, programmable three degree-of-freedom traverse system has also been incorporated into the water channel, allowing automated positioning of the ADV probes along the SRVL glideslope with sub-millimetre accuracy. Finally, the validated CFD airwakes were incorporated into the HELIFLIGHT-R piloted flight simulator at Liverpool, for which a QEC simulation environment has been developed. Two former Royal Navy test pilots then performed a series of landings to the deck of the QEC in a Sikorsky SH-60 Seahawk, to demonstrate this newly developed capability at Liverpool, and to provide an initial assessment of pilot workload in varying wind speeds and azimuths, prior to real-world FOCFTs. The findings of this initial flight testing is reported in this thesis, as are conclusions and recommendations for future work

    Pills and prayers: a comparative qualitative study of community conceptualisations of pre-eclampsia and pluralistic care in Ethiopia, Haiti and Zimbabwe.

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    BACKGROUND: Pre-eclampsia is a leading cause of preventable maternal and perinatal deaths globally. While health inequities remain stark, removing financial or structural barriers to care does not necessarily improve uptake of life-saving treatment. Building on existing literature elaborating the sociocultural contexts that shape behaviours around pregnancy and childbirth can identify nuanced influences relating to pre-eclampsia care. METHODS: We conducted a cross-cultural comparative study exploring lived experiences and understanding of pre-eclampsia in Ethiopia, Haiti and Zimbabwe. Our primary objective was to examine what local understandings of pre-eclampsia might be shared between these three under-resourced settings despite their considerable sociocultural differences. Between August 2018 and January 2020, we conducted 89 in-depth interviews with individuals and 17 focus group discussions (n = 106). We purposively sampled perinatal women, survivors of pre-eclampsia, families of deceased women, partners, older male and female decision-makers, traditional birth attendants, religious and traditional healers, community health workers and facility-based health professionals. Template analysis was conducted to facilitate cross-country comparison drawing on Social Learning Theory and the Health Belief Model. RESULTS: Survivors of pre-eclampsia spoke of their uncertainty regarding symptoms and diagnosis. A lack of shared language challenged coherence in interpretations of illness related to pre-eclampsia. Across settings, raised blood pressure in pregnancy was often attributed to psychosocial distress and dietary factors, and eclampsia linked to spiritual manifestations. Pluralistic care was driven by attribution of causes, social norms and expectations relating to alternative care and trust in biomedicine across all three settings. Divergence across the contexts centred around nuances in religious or traditional practices relating to maternal health and pregnancy. CONCLUSIONS: Engaging faith and traditional caregivers and the wider community offers opportunities to move towards coherent conceptualisations of pre-eclampsia, and hence greater access to potentially life-saving care

    Geographic Coincidence of Increased Malaria Transmission Hazard and Vulnerability Occurring at the Periphery of two Tanzanian Villages.

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    The goal of malaria elimination necessitates an improved understanding of any fine-scale geographic variations in transmission risk so that complementary vector control tools can be integrated into current vector control programmes as supplementary measures that are spatially targeted to maximize impact upon residual transmission. This study examines the distribution of host-seeking malaria vectors at households within two villages in rural Tanzania. Host-seeking mosquitoes were sampled from 72 randomly selected households in two villages on a monthly basis throughout 2008 using CDC light-traps placed beside occupied nets. Spatial autocorrelation in the dataset was examined using the Moran's I statistic and the location of any clusters was identified using the Getis-Ord Gi* statistic. Statistical associations between the household characteristics and clusters of mosquitoes were assessed using a generalized linear model for each species. For both Anopheles gambiae sensu lato and Anopheles funestus, the density of host-seeking females was spatially autocorrelated, or clustered. For both species, houses with low densities were clustered in the semi-urban village centre while houses with high densities were clustered in the periphery of the villages. Clusters of houses with low or high densities of An. gambiae s.l. were influenced by the number of residents in nearby houses. The occurrence of high-density clusters of An. gambiae s.l. was associated with lower elevations while An. funestus was also associated with higher elevations. Distance from the village centre was also positively correlated with the number of household occupants and having houses constructed with open eaves. The results of the current study highlight that complementary vector control tools could be most effectively targeted to the periphery of villages where the households potentially have a higher hazard (mosquito densities) and vulnerability (open eaves and larger households) to malaria infection

    Use, Practices and Attitudes of Sports Nutrition and Strength and Conditioning Practitioners towards Tart Cherry Supplementation

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    This is the final version. Available from MDPI via the DOI in this record. No new data were created or analyzed in this study. Data sharing is not applicable to this article.Tart cherry (TC) supplementation has been shown to accelerate post-exercise recovery, enhance endurance performance and improve sleep duration and quality. This study aimed to identify the use, practices and attitudes of sports nutrition and strength and conditioning practitioners towards tart cherry supplementation. Thirty-five practitioners anonymously completed an online survey investigating their use, practices and attitudes towards tart cherry supplements. Forty-six percent of the responders were currently recommending TC supplements, 11% had previously recommended TC supplements and 26% have not previously recommended TC supplements but were planning on doing so in the future. Of those recommending TC, 50% recommended or were planning on recommending TC supplements to enhance exercise recovery and 26% to improve sleep duration and quality. Acute supplementation and daily use during multi-day competition or demanding training blocks with a 2–3-day pre-load were the most reported supplementation recommendations (28% and 18%, respectively). Fifty-two percent of responders indicated uncertainty about the daily polyphenol dose to recommend as part of a TC supplementation protocol. Despite the high use and interest from sports nutrition and strength and conditioning practitioners in TC supplements, their practices did not align with the protocols found to be effective within the literature

    The Role of Modelling and Simulation in the Preparations for Flight Trials Aboard the Queen Elizabeth Class Aircraft Carriers

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    This paper provides a brief overview of how modelling and simulation has been used to inform preparations for First of Class Flight Trials (FOCFT) aboard HMS Queen Elizabeth, the first of the United Kingdom’s two new Queen Elizabeth Class aircraft carriers, from the perspective of a collaborative research programme undertaken by industry and academia to develop high-fidelity simulations of the carrier’s ‘airwake’.  Computer modelling of the unsteady air flow over the carrier, and of the aircraft flight dynamics, have been integrated into high-fidelity flight simulators at BAE Systems Warton, and at the University of Liverpool.  The Queen Elizabeth Class (QEC) carriers have primarily been designed to operate the Short Take-Off and Vertical Landing (STOVL) variant of the Lockheed Martin F-35 Lightning II multirole fighter aircraft and will also operate a range of rotary-wing assets.  Computational Fluid Dynamics (CFD) has been used to compute the time-varying air flow over and around the 280m long ship, along the F-35B landing approach path and up to 400m astern of the ship.  The paper shows a selection of results from the full-scale CFD analysis, and the results from a small-scale experiment that was conducted to provide confidence in the validity of the computed airwakes.  The QEC airwakes have been employed by BAE Systems in its fixed-wing flight simulator at Warton, where test pilots have conducted simulated deck landings for a variety of wind over deck conditions, so providing experience for F-35B test pilots and the ship’s Flying Control (FLYCO) crew ahead of FOCFT, which will be conducted later this year.  Airwakes have also been implemented in the HELIFLIGHT-R flight simulator at the University of Liverpool, where helicopter landings to the QEC have been simulated using a generic medium-weight maritime-helicopter model. A selection of results from the helicopter flight simulator trials is presented in terms of the workload ratings reported by test pilots, and these are related to the characteristics of the computed airwake at the landing spots tested.  The paper demonstrates how modelling and simulation can be used to reduce both the risk and cost of flight trials, by informing the FOCFT planning process, and by highlighting, in advance of the trials, which wind speed and azimuth combinations may require more focus.  </jats:p
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