1,006 research outputs found

    Relay Based Robot For Automated Isolating Systems Used In Steering Gear Of A Ship : Comparative Performance Analysis With Manual System

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    According to SOLAS, it is mandatory to provide all sailing vessels with an efficient main steering gear as well as an auxiliary steering gear. For turning the ship to the left (port side) or to the right (starboard side), while sailing, the steering gear is used. The requirement is that the main steering gear should be power operated except in the case of very small vessels/ships. The steering gear control system is the equipment by which helm orders/autopilot orders are transferred from the wheelhouse to the power units of the steering gear. The Steering Gear control system consists of the electrical wiring, electrical motors, hydraulic pumps, piping, receivers, transmitters, and control equipment. This paper focuses on relay based Robot for automated isolating Systems used in Steering Gear of a Ship and the comparison of the performance of a manual isolating system and Automatic Isolating system with robotic relay logic control. An experimental hardware prototype is designed and developed to compare the performance of steering gear isolating systems. The developed hardware is tested successfully and found that, it is better with respect to the following features. Fault Isolation time. Independent operation. Operation of steering gear in various healthy and faulty conditions

    Quantum phase transitions of light

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    Recently, condensed matter and atomic experiments have reached a length-scale and temperature regime where new quantum collective phenomena emerge. Finding such physics in systems of photons, however, is problematic, as photons typically do not interact with each other and can be created or destroyed at will. Here, we introduce a physical system of photons that exhibits strongly correlated dynamics on a meso-scale. By adding photons to a two-dimensional array of coupled optical cavities each containing a single two-level atom in the photon-blockade regime, we form dressed states, or polaritons, that are both long-lived and strongly interacting. Our zero temperature results predict that this photonic system will undergo a characteristic Mott insulator (excitations localised on each site) to superfluid (excitations delocalised across the lattice) quantum phase transition. Each cavity's impressive photon out-coupling potential may lead to actual devices based on these quantum many-body effects, as well as observable, tunable quantum simulators. We explicitly show that such phenomena may be observable in micro-machined diamond containing nitrogen-vacancy colour centres and superconducting microwave strip-line resonators.Comment: 11 pages, 5 figures (2 in colour

    Using molecular data for epidemiological inference: assessing the prevalence of Trypanosoma brucei rhodesiense in Tsetse in Serengeti, Tanzania

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    Background: Measuring the prevalence of transmissible Trypanosoma brucei rhodesiense in tsetse populations is essential for understanding transmission dynamics, assessing human disease risk and monitoring spatio-temporal trends and the impact of control interventions. Although an important epidemiological variable, identifying flies which carry transmissible infections is difficult, with challenges including low prevalence, presence of other trypanosome species in the same fly, and concurrent detection of immature non-transmissible infections. Diagnostic tests to measure the prevalence of T. b. rhodesiense in tsetse are applied and interpreted inconsistently, and discrepancies between studies suggest this value is not consistently estimated even to within an order of magnitude. Methodology/Principal Findings: Three approaches were used to estimate the prevalence of transmissible Trypanosoma brucei s.l. and T. b. rhodesiense in Glossina swynnertoni and G. pallidipes in Serengeti National Park, Tanzania: (i) dissection/microscopy; (ii) PCR on infected tsetse midguts; and (iii) inference from a mathematical model. Using dissection/microscopy the prevalence of transmissible T. brucei s.l. was 0% (95% CI 0–0.085) for G. swynnertoni and 0% (0–0.18) G. pallidipes; using PCR the prevalence of transmissible T. b. rhodesiense was 0.010% (0–0.054) and 0.0089% (0–0.059) respectively, and by model inference 0.0064% and 0.00085% respectively. Conclusions/Significance: The zero prevalence result by dissection/microscopy (likely really greater than zero given the results of other approaches) is not unusual by this technique, often ascribed to poor sensitivity. The application of additional techniques confirmed the very low prevalence of T. brucei suggesting the zero prevalence result was attributable to insufficient sample size (despite examination of 6000 tsetse). Given the prohibitively high sample sizes required to obtain meaningful results by dissection/microscopy, PCR-based approaches offer the current best option for assessing trypanosome prevalence in tsetse but inconsistencies in relating PCR results to transmissibility highlight the need for a consensus approach to generate meaningful and comparable data

    Magnetism, FeS colloids, and Origins of Life

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    A number of features of living systems: reversible interactions and weak bonds underlying motor-dynamics; gel-sol transitions; cellular connected fractal organization; asymmetry in interactions and organization; quantum coherent phenomena; to name some, can have a natural accounting via physicalphysical interactions, which we therefore seek to incorporate by expanding the horizons of `chemistry-only' approaches to the origins of life. It is suggested that the magnetic 'face' of the minerals from the inorganic world, recognized to have played a pivotal role in initiating Life, may throw light on some of these issues. A magnetic environment in the form of rocks in the Hadean Ocean could have enabled the accretion and therefore an ordered confinement of super-paramagnetic colloids within a structured phase. A moderate H-field can help magnetic nano-particles to not only overcome thermal fluctuations but also harness them. Such controlled dynamics brings in the possibility of accessing quantum effects, which together with frustrations in magnetic ordering and hysteresis (a natural mechanism for a primitive memory) could throw light on the birth of biological information which, as Abel argues, requires a combination of order and complexity. This scenario gains strength from observations of scale-free framboidal forms of the greigite mineral, with a magnetic basis of assembly. And greigite's metabolic potential plays a key role in the mound scenario of Russell and coworkers-an expansion of which is suggested for including magnetism.Comment: 42 pages, 5 figures, to be published in A.R. Memorial volume, Ed Krishnaswami Alladi, Springer 201

    Trial baseline characteristics of a cluster randomised controlled trial of a school-located obesity prevention programme; the Healthy Lifestyles Programme (HeLP) trial

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    BACKGROUND: We have developed a healthy lifestyles programme (HeLP) for primary school aged children (9-10 years), currently being evaluated in a definitive cluster randomised controlled trial. This paper descriptively presents the baseline characteristics of trial children (BMI, waist circumference, % body fat, diet and physical activity) by gender, cluster level socio-economic status, school size and time of recruitment into the trial. METHODS: Schools were recruited from across the South West of England and allocated 1:1 to either intervention (HeLP) or control (usual practice) stratified by the proportion of children eligible for free school meals (FSM, \u3c19%, =19%) and school size (one Year 5 class, \u3e1 Year 5 class). The primary outcome is change in body mass index standard deviation score (BMI sds) at 24 months post-randomisation. Secondary outcomes are BMI sds at 18 months, waist circumference and percentage body fat sds at 18 and 24 months, proportion of children classified as underweight, overweight and obese at 18 and 24 months, physical activity (for a sub-sample) and food intake at 18 months. RESULTS: At baseline 11.4% and 13.6% of children were categorised as overweight or obese respectively. A higher percentage of girls than boys (25.3% vs 24.8%) and children from schools in FSM category 2 (28.2% vs 23.2%) were overweight or obese. Children were consuming a mean (range) of 4.15 (0-13) energy dense snacks (EDS) and 3.23 (0-9) healthy snacks (HS) per day with children from schools in FSM category 2 consuming more EDS and negative food markers and less HS and positive food markers. Children spent an average 53.6 min per day (11.9 to 124.8) in MVPA and thirteen hours (779.3 min) per day (11 h to 15 h) doing less than \u27light\u27 intensity activity. Less than 5% of children achieved the Departments of Health\u27s recommendation of 60 min of MVPA every day. CONCLUSION: We have excellent completeness of baseline data for all measures and have achieved compliance to accelerometry not seen before in other large scale studies. Our anthropometric baseline data is representative of local and national data for children this age and reflects the gender and socio-economic variations expected of children this age in relation to physical activity and weight status. TRIAL REGISTRATION: ISRCTN15811706 (1/05/2012)

    Are We Overestimating Physical Activity Prevalence in Children?

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    Background: Physical activity guidelines state that children should achieve at least 60 minutes of moderate to vigorous physical activity (MVPA) on each day of the week. Accurate assessment of adherence to these guidelines should, ideally, include measurement over 7 days. When less than 7 days of data are available, researchers often report the average minutes of MVPA per day as a proxy for 7-day measurement. The aim of this study was to compare prevalence estimates generated by average MVPA per day versus MVPA assessed over 7 days. Methods: Data were collected as part of the Healthy Lifestyles Programme. One class from each school was randomized to wear a GENEActiv accelerometer for 8 days. The percentages of children achieving an average of =60 minutes of MVPA per day and those achieving =60 minutes of MVPA on each of 7 days were calculated. Results: A total of 807 children provided 7 days of data. When the average MVPA per day was calculated, 30.6% (n = 247) of children accumulated =60 minutes of MVPA per day. Only 3.2% (n = 26) accumulated =60 minutes of MVPA on every day of the week. Conclusion: Previous studies utilizing average MVPA per day are likely to have overestimated the percentage of children meeting recommendations

    Detailed statistical analysis plan for a cluster randomised controlled trial of the Healthy Lifestyles Programme (HeLP), a novel school-based intervention to prevent obesity in school children

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    Background The Healthy Lifestyles Programme (HeLP) trial is being conducted to determine whether a novel school-based intervention is effective and cost-effective in preventing obesity in 9–10 year-old children. This article describes the detailed statistical analysis plan for the HeLP trial, including an amendment (and rationale for amendment) made to originally planned sensitivity analyses. Methods and design The HeLP trial is a definitive, pragmatic, superiority, cluster randomised controlled trial with two parallel groups and blinded outcome assessment. This update article describes in detail (1) the primary and secondary outcomes, (2) the statistical analysis principles (including which children will be included in each analysis, how the clustered nature of the study design will be accounted for, which covariates will be included in each analysis, how the results will be presented), (3) planned sensitivity analyses, planned subgroup analyses and planned adherence-adjusted analyses for the primary outcome, (4) planned analyses for the secondary outcomes and (e) planned longitudinal analyses. Trial registration International Standard Randomised Controlled Trial Number (ISRCTN) register: ISRCTN15811706. Registered on 1 May 2012

    Children’s Compliance With Wrist-Worn Accelerometry Within a Cluster-Randomized Controlled Trial: Findings From the Healthy Lifestyles Programme

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    Purpose: The purpose of this study was to assess children’s compliance with wrist-worn accelerometry during a randomized controlled trial and to examine whether compliance differed by allocated condition or gender. Methods: A total of 886 children within the Healthy Lifestyles Programme trial were randomly allocated to wear a GENEActiv accelerometer at baseline and 18-month follow-up. Compliance with minimum wear-time criteria (=10 h for 3 weekdays and 1 weekend day) was obtained for both time points. Chi-square tests were used to determine associations between compliance, group allocation, and gender. Results: At baseline, 851 children had usable data, 830 (97.5%) met the minimum wear-time criteria, and 631 (74.1%) had data for 7 days at 24 hours per day. At follow-up, 789 children had usable data, 745 (94.4%) met the minimum wear-time criteria, and 528 (67%) had complete data. Compliance did not differ by gender (baseline: ?2 = 1.66, P = .2; follow-up: ?2 = 0.76, P = .4) or by group at follow-up (?2 = 2.35, P = .13). Conclusion: The use of wrist-worn accelerometers and robust trial procedures resulted in high compliance at 2 time points regardless of group allocation, demonstrating the feasibility of using precise physical activity monitors to measure intervention effectiveness

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
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