1,931 research outputs found

    Cardiopulmonary exercise testing in children with Cystic Fibrosis : one centre’s experience

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    Exercise testing is increasingly being used as a prognostic indicator in Cystic Fibrosis (CF) but it is reported to be underutilised in UK CF centres, particularly in children. Here, we evaluated the CPET results of our children with CF at the CF annual review and its possible clinical value

    Influence of controlled fluid shear on nucleation rates in glycine aqueous solutions

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    The nucleation of glycine was investigated in supersaturated aqueous solutions exposed to well-controlled fluid shear under isothermal conditions. Shear rates between 25 s-1 and 1000 s-1 were studied using Couette and capillary flow devices. Induction times were obtained from imaging, transmission and scattering measurements, or visual monitoring. Great care was taken to eliminate any seeding in order to avoid secondary nucleation preceding formation of first crystals through primary nucleation. The observed induction times of sheared solutions were considerably lower than those of unsheared solutions. Increasing the average shear rate was found to reduce the mean induction time through a power law relationship. A detailed statistical analysis showed that the number of experimental repetitions used was sufficient to obtain statistically significant trends for the system studied. Induction times appeared to closely follow a probability distribution based on a previously published model of Jiang and ter Horst. Using their model, where the induction time is related to the rate of formation of primary nuclei and the time it takes them to grow to the size where the secondary nucleation becomes significant, it was found that both the primary nucleation rate and the growth time were strongly dependent on the shear rate imposed

    Monolithic integrated high-T.sub.c superconductor-semiconductor structure

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    A method for the fabrication of active semiconductor and high-temperature superconducting device of the same substrate to form a monolithically integrated semiconductor-superconductor (MISS) structure is disclosed. A common insulating substrate, preferably sapphire or yttria-stabilized zirconia, is used for deposition of semiconductor and high-temperature superconductor substructures. Both substructures are capable of operation at a common temperature of at least 77 K. The separate semiconductor and superconductive regions may be electrically interconnected by normal metals, refractory metal silicides, or superconductors. Circuits and devices formed in the resulting MISS structures display operating characteristics which are equivalent to those of circuits and devices prepared on separate substrates

    Method for making a monolithic integrated high-T.sub.c superconductor-semiconductor structure

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    A method for the fabrication of active semiconductor and high-temperature perconducting devices on the same substrate to form a monolithically integrated semiconductor-superconductor (MISS) structure is disclosed. A common insulating substrate, preferably sapphire or yttria-stabilized zirconia, is used for deposition of semiconductor and high-temperature superconductor substructures. Both substructures are capable of operation at a common temperature of at least 77 K. The separate semiconductor and superconductive regions may be electrically interconnected by normal metals, refractory metal silicides, or superconductors. Circuits and devices formed in the resulting MISS structures display operating characteristics which are equivalent to those of circuits and devices prepared on separate substrates

    Pollutant dispersion in a developing valley cold-air pool

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    Pollutants are trapped and accumulate within cold-air pools, thereby affecting air quality. A numerical model is used to quantify the role of cold-air-pooling processes in the dispersion of air pollution in a developing cold-air pool within an alpine valley under decoupled stable conditions. Results indicate that the negatively buoyant downslope flows transport and mix pollutants into the valley to depths that depend on the temperature deficit of the flow and the ambient temperature structure inside the valley. Along the slopes, pollutants are generally entrained above the cold-air pool and detrained within the cold-air pool, largely above the ground-based inversion layer. The ability of the cold-air pool to dilute pollutants is quantified. The analysis shows that the downslope flows fill the valley with air from above, which is then largely trapped within the cold-air pool, and that dilution depends on where the pollutants are emitted with respect to the positions of the top of the ground-based inversion layer and cold-air pool, and on the slope wind speeds. Over the lower part of the slopes, the cold-air-pool-averaged concentrations are proportional to the slope wind speeds where the pollutants are emitted, and diminish as the cold-air pool deepens. Pollutants emitted within the ground-based inversion layer are largely trapped there. Pollutants emitted farther up the slopes detrain within the cold-air pool above the ground-based inversion layer, although some fraction, increasing with distance from the top of the slopes, penetrates into the ground-based inversion layer.Peer reviewe

    Reading the Complex Skipper Butterfly Fauna of One Tropical Place

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    BACKGROUND: An intense, 30-year, ongoing biodiversity inventory of Lepidoptera, together with their food plants and parasitoids, is centered on the rearing of wild-caught caterpillars in the 120,000 terrestrial hectares of dry, rain, and cloud forest of Area de Conservacion Guanacaste (ACG) in northwestern Costa Rica. Since 2003, DNA barcoding of all species has aided their identification and discovery. We summarize the process and results for a large set of the species of two speciose subfamilies of ACG skipper butterflies (Hesperiidae) and emphasize the effectiveness of barcoding these species (which are often difficult and time-consuming to identify). METHODOLOGY/PRINCIPAL FINDINGS: Adults are DNA barcoded by the Biodiversity Institute of Ontario, Guelph, Canada; and they are identified by correlating the resulting COI barcode information with more traditional information such as food plant, facies, genitalia, microlocation within ACG, caterpillar traits, etc. This process has found about 303 morphologically defined species of eudamine and pyrgine Hesperiidae breeding in ACG (about 25% of the ACG butterfly fauna) and another 44 units indicated by distinct barcodes (n = 9,094), which may be additional species and therefore may represent as much as a 13% increase. All but the members of one complex can be identified by their DNA barcodes. CONCLUSIONS/SIGNIFICANCE: Addition of DNA barcoding to the methodology greatly improved the inventory, both through faster (hence cheaper) accurate identification of the species that are distinguishable without barcoding, as well as those that require it, and through the revelation of species "hidden" within what have long been viewed as single species. Barcoding increased the recognition of species-level specialization. It would be no more appropriate to ignore barcode data in a species inventory than it would be to ignore adult genitalia variation or caterpillar ecology

    The Multi-Object, Fiber-Fed Spectrographs for SDSS and the Baryon Oscillation Spectroscopic Survey

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    We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5-m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Lyman-alpha absorption of 160,000 high redshift quasars over 10,000 square degrees of sky, making percent level measurements of the absolute cosmic distance scale of the Universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber spectrographs utilize a simple optical layout with reflective collimators, gratings, all-refractive cameras, and state-of-the-art CCD detectors to produce hundreds of spectra simultaneously in two channels over a bandpass covering the near ultraviolet to the near infrared, with a resolving power R = \lambda/FWHM ~ 2000. Building on proven heritage, the spectrographs were upgraded for BOSS with volume-phase holographic gratings and modern CCD detectors, improving the peak throughput by nearly a factor of two, extending the bandpass to cover 360 < \lambda < 1000 nm, and increasing the number of fibers from 640 to 1000 per exposure. In this paper we describe the original SDSS spectrograph design and the upgrades implemented for BOSS, and document the predicted and measured performances.Comment: 43 pages, 42 figures, revised according to referee report and accepted by AJ. Provides background for the instrument responsible for SDSS and BOSS spectra. 4th in a series of survey technical papers released in Summer 2012, including arXiv:1207.7137 (DR9), arXiv:1207.7326 (Spectral Classification), and arXiv:1208.0022 (BOSS Overview

    An Analysis of the Legal, Social, and Political Issues Raised by Asbestos Litigation

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    This Special Project examines the most important issues of the asbestos problem and advocates a congressional solution (1) to relieve the courts of the thousands of present and potential asbestos cases, (2) to protect future claimants\u27 rights to adequate compensation, and (3) to provide for equitable participation by all responsible parties, which, in addition to asbestos manufacturers,include the federal government, insurance companies, and the tobacco industry. The first six parts of the Special Project examine the various issues of asbestos litigation: theories of liability in products liability suits against asbestos manufacturers, causation,defenses, statutory limitations on actions, collateral estoppel, and punitive damages. The Special Project then discusses in parts VIII,IX, and X the methods used by asbestos manufacturers to attempt to spread their liability through asserting insurer liability, the exclusive remedy of workers\u27 compensation, and indemnity and contribution from the United States. Finally, the Special Project evaluates and analyzes recent developments in the asbestos litigation area, including proposals for federal legislative compensation programs and business alternatives available to asbestos manufacturers facing enormous asbestos-related liabilities... This Special Project critically has examined the most important issues concerning the asbestos problem. It has considered the complex legal, legislative, and social questions that society must confront in order to resolve this predicament. Only swift action by Congress in the form of a fair and comprehensive compensation scheme for victims of asbestos-related disabilities will initiate a solution to this difficult and pervasive problem
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