6,329 research outputs found

    The changes in chemical composition during development of the bovine nuchal ligament

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    Whole bovine nuchal ligaments, or portions thereof (in the case of commercially valuable animals), were obtained from 45 animals (28 fetal and 17 postnatal) ranging in age from 110 days of gestation to 10 yr. Insoluble elastin was quantitatively prepared from the fresh ligaments by extraction with hot alkali and by a combination of multiple extractions with alkaline buffer and then repeated autoclaving. When adult samples were examined, the yields of insoluble residue by these two methods were very similar, but with young fetal samples the second method gave significantly higher values, because of incomplete purification of the elastin residue. The changes in the concentration of collagen, alkali-insoluble elastin, and DNA have been examined. DNA concentration, and, thus, cell population density, fell progressively during the fetal period of development, to reach a steady value soon after birth. Collagen appeared in appreciable quantities before elastin, but its concentration was rapidly halved at about the time of birth. Insoluble elastin concentration was low until the end of the 7th fetal month, at which time it began to rise rapidly. The rate of increase in elastin concentration remained high throughout the next 10–12 wk, by which time the adult value had been reached. Quantitative studies, on the basis of the whole ligament, showed that the total cell content rises to a maximum at birth, but falls soon after to a level about half that at birth. Total collagen production and elastin deposition continue at a steady, maximal rate over the interval from 235 days of gestation to the end of the 1st postnatal month. It is concluded that the immediate postnatal period would be the most favorable phase in which to attempt the isolation of the soluble precursor elastin

    Results of tests of a 0.010- and 0.015-scale models of space shuttle orbiter configurations 3 and 3A in the Ames Research Center 3.5 foot hypersonic wind tunnel (OA23)

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    Longitudinal and lateral-directional stability and control characteristics were evaluated at Mach numbers of 5.3, 7.3 and 10.3 at angles of attack up to 50 degrees with Beta = 0 degrees and, for a few cases, Beta = 5 degrees. Component force data, fuselage base pressures and shadowgraph patterns were recorded

    Towards a virtual comminution machine

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    Towards the end of the 1990s readily available personal computers became sufficiently powerful - when combined with an efficient numerical code - to use discrete element modelling (DEM) in two dimensions for models involving a few hundred to a few thousand particles in commercially available packages. Some proprietary codes reported up to 200,000 particles [Herbst, J.A., Nordell, L., 2001. Optimization of the design of sag mill internals using high fidelity simulation. In: Vancouver, B.C., Barratt, D.J., Allan, M.J., Mular, A.L. (Eds.), Proceedings of the SAG Conference, University of British Columbia, IV, 150-164; Cleary, P.W., 2001a. Charge behaviour and power consumption in ball mills: Sensitivity to mill operating conditions, liner geometry and charge composition. Int. J. Min. Process. 63, 79-114 and Cleary, P.W., 2001b. Recent advances in DEM modelling of tumbling mills. Minerals Eng. 14, 1295-1319]. In early 2000, JKMRC and CSIRO-MIS agreed to an informal collaboration with the objective of testing various DEM approaches against detailed process measurements. The initial collaboration demonstrated that 3D-DEM using spheres was sufficiently realistic for flow patterns and power estimation within tumbling mills. The results were reported in papers which were presented at SAG 2001 and in the technical literature [Morrison, R.D., Cleary, P.W., Valery, W., 2001. Comparing power and performance trends from DEM and JK modelling. SAG 2001, Department of Mining and Minerals Process Engineering. University of British Columbia, Vancouver, 284-300; Cleary, P.W., Morrison, R., Morrell, S., 2003. Comparison of DEM and experiment for a scale model SAG mill. Int. J. Min. Process. 68, 129-165]. The commencement of the CRC for Sustainable Resource Processing in 2003 provided an opportunity to formalize the collaboration and bring increased resources to bear. The objective of this collaboration is to develop a virtual comminution machine (VCM). The VCM will allow a comminution machine design which exists as a suitably detailed design in a 3D Computer aided design file (CAD) to simulate processing an ore (which has been characterised by suitable test work) to predict progeny, power consumption, wear and even machine component loadings. This paper reports on the substantial progress made to date towards a practical Virtual Comminution Machine

    Eliminating artefacts in polarimetric images using deep learning

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    Polarization measurements done using Imaging Polarimeters such as the Robotic Polarimeter are very sensitive to the presence of artefacts in images. Artefacts can range from internal reflections in a telescope to satellite trails that could contaminate an area of interest in the image. With the advent of wide-field polarimetry surveys, it is imperative to develop methods that automatically flag artefacts in images. In this paper, we implement a Convolutional Neural Network to identify the most dominant artefacts in the images. We find that our model can successfully classify sources with 98 per cent true positive and 97 per cent true negative rates. Such models, combined with transfer learning, will give us a running start in artefact elimination for near-future surveys like WALOP

    Results of investigations on an 0.015-scale 140A/B configuration of the Rockwell International space shuttle orbiter (model 49-O) in the NASA/Ames Research Center 3.5-foot hypersonic wind tunnel (OA36)

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    The results of wind tunnel tests of the 140A/B configuration components are reported for the fuselage, canopy, elevons, bodyflaps, pods, engine nozzles, rudder, vertical tail, and wing. The test facility, and data reduction procedures are described. Test results for each component are graphed, and tabulated source data are included

    Transportability of tertiary qualifications and CPD: A continuing challenge for the global health workforce

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    Background: In workforces that are traditionally mobile and have long lead times for new supply, such as health, effective global indicators of tertiary education are increasingly essential. Difficulties with transportability of qualifications and cross-accreditation are now recognised as key barriers to meeting the rapidly shifting international demands for health care providers. The plethora of mixed education and service arrangements poses challenges for employers and regulators, let alone patients; in determining equivalence of training and competency between individuals, institutions and geographical locations. Discussion: This paper outlines the shortfall of the current indicators in assisting the process of global certification and competency recognition in the health care workforce. Using Organisation for Economic Cooperation and Development (OECD) data we highlight how International standardisation in the tertiary education sector is problematic for the global health workforce. Through a series of case studies, we then describe a model which enables institutions to compare themselves internally and with others internationally using bespoke or prioritised parameters rather than standards. Summary: The mobility of the global health workforce means that transportability of qualifications is an increasing area of concern. Valid qualifications based on workplace learning and assessment requires at least some variables to be benchmarked in order to judge performance. © 2012 Saltman et al.; licensee BioMed Central Ltd

    Democracy and development

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