2,265 research outputs found

    SESAME, a third generation synchrotron light source for the Middle East region

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    Developed under the auspices of UNESCO, SESAME is being established as an autonomous international research centre in the Middle East/Mediterranean region. It will have as its centrepiece a 2.5 GeV third Generation synchrotron light source with 13 straight sections for insertion devices and an emittance of 26.6 nm-rad. It will provide intense radiation from the IR to hard X-rays to a community that is expected to exceed 1000 users a few years after the start of operation in 2008

    Vorticism in aeronautics

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    Since the war there has been a considerable advance in knowledge on the subject of the airfoil and its behavior. The theory is now sufficiently advanced to make it possible to predict and to calculate certain results which previously could only be attained by direct experiment. The vortex theory receives special attention

    IDENTIFICATION OF THE POP-UP ACCELERATION WAVEFORM SIGNAL: A CASE STUDY

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    The purpose of this case study was to assess the feasibility of using accelerometers to identify and analyse the acceleration waveform signals of the pop-up movement. An experienced male recreational surfer performed 10 dry-land pop-ups with accelerometers (1000 Hz) attached to the sacrum and lateral aspect of each shank. The waveform signals of the pop-up were successfully identified at each instrumentation site using a combination of acceleration and video data. Several movement events that occurred during the pop-up were also able to be detected within each of the mean resultant acceleration signals. These findings suggest that accelerometers can viably be used to detect and analyse the waveform signals of the pop-up. This provides initial evidence that accelerometers are a suitable tool for collecting kinematic data of surfing performances

    Measurement of Plane Stress States using Electromagnetic-Acoustic Transducers

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    Assessment of structural safety requires knowledge of the shape of any defect and the stresses acting on it. Ultrasonics can be used to measure applied stress since there is a (small) change in velocity with stress. However the problem becomes more difficult when measuring residual stress. Here the influence of other factors such as variation in microstructure must be accounted for. For example, one method is to measure the percent difference in velocity of orthogonally polarized shear waves (the acoustic birefringence B). When the material symmetry and stress axes coincide [1], B=Bo+CaD where Be is the birefringence in the unstressed state, Ca is the acoustoelastic constant and D is the difference of principal stresses. The usual procedure is to measure B at a “reference” location where stresses are known, and assume homogeneity of microstructure

    Evaluation of Pooled Serum and ‘Meat-Juice’ in a Salmonella ELISA for Pig Herds

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    Samples of ‘meat-juice’, serum, caecal contents and carcase swabs from 420 pigs from 20 finishing farms were tested for Salmonella bacteriologically and serologically by ELISA on individual samples or on pools of serum or meat juice. In addition pooled floor faeces were taken from the finishing pens on the farm of origin

    High impact activity is related to lean but not fat mass:findings from a population-based study in adolescents

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    Background Objective measures of physical activity calibrated against energy expenditure may have limited utility in studying relationships with musculoskeletal phenotypes. We wished to assess an alternative approach using an accelerometer calibrated according to impact loading. Methods Of the 17-year olds from the Avon Longitudinal Study of Parents and Children (ALSPAC), 732 wore Newtest accelerometers while performing day-to-day activities for a mean of 5.8 days. Outputs were categorized as light, moderate, high and very high impact, based on the thresholds identified in 22 adolescents during graded activities. In subsequent regression analyses, activity data and fat mass were normalized by log transformation. Results The number of counts relating to high impact activity was ∼2% that of light impact activity, and 33% greater in boys when compared with girls. High impact activity was more strongly related to lean mass [light: 0.033 (95% CI −0.023 to 0.089), moderate: 0.035 (95% CI −0.010 to 0.080) and high: 0.044 (95% CI 0.010 to 0.078)] (β = SD change in outcome per doubling in activity, height adjusted, boys and girls combined). In contrast, lower impact activity was more strongly related to fat mass [light: −0.069 (95% CI −0.127 to −0.011), moderate: −0.060 (95% CI −0.107 to −0.014) and high: −0.033 (95% CI −0.069 to 0.003)]. In a more fully adjusted model including other activity types and fat/lean mass, lean mass was related to only high activity (boys and girls combined), whereas fat mass was related to only moderate activity (girls only). Conclusions Using an accelerometer calibrated according to impact loading revealed that high impact activity is related to lean but not fat mass

    Comparison of two commercial ELISA kits and bacteriology for Salmonella monitoring in pig herds

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    Samples of ‘meat-juice’ and serum from 170 pigs from 20 finishing farms were tested for Salmonella using two commercial ELISA kit tests. In parallel samples from caecal contents and pooled pen faeces from the farm were tested by culture. Both ELISA’s gave significantly correlated results with each other but only ELISA B, at a 20 % calculated OD % on ‘meat juice’, gave a result which correlated significantly with the percentage of positive pen faeces. None of the ELISA tests correlated with caecal positives and the 10 % cut-off level was shown to be unsuitable for monitoring commercial herds

    Australian Aboriginal Birth Cohort study: follow-up processes at 20 years

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    Background: In 1987, a prospective study of an Australian Aboriginal Birth Cohort was established focusing on the relationships of fetal and childhood growth with the risk of chronic adult disease. However as the study is being conducted in a highly marginalized population it is also an important resource for cross-sectional descriptive and analytical studies. The aim of this paper is to describe the processes of the third follow up which was conducted 20 years after recruitment at birth. Methods: Progressive steps in a multiphase protocol were used for tracing, with modifications for the expected rural or urban location of the participants. Results: Of the original 686 cohort participants recruited 68 were untraced and 27 were known to have died. Of the 591 available for examination 122 were not examined; 11 of these were refusals and the remainder were not seen for logistical reasons relating to inclement weather, mobility of participants and single participants living in very remote locations. Conclusion: The high retention rate of this follow-up 20 years after birth recruitment is a testament to the development of successful multiphase protocols aimed at overcoming the challenges of tracing a cohort over a widespread remote area and also to the perseverance of the study personnel. We also interpret the high retention rate as a reflection of the good will of the wider Aboriginal community towards this study and that researchers interactions with the community were positive. The continued follow-up of this life course study now seems feasible and there are plans to trace and reexamine the cohort at age 25 years.Susan Sayers, Gurmeet Singh, Dorothy Mackerras, Megan Lawrance,Wendy Gunthorpe, Lisa Jamieson, Belinda Davison, Kobi Schutz and Joseph Fit
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