9,930 research outputs found

    List Size, Standards and Perfromance in General Practice - A Pilot Study in the South East Thames Region

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    This is a report of a piolt study carried out among 155 general practitioner trainers in South East Thames region. Similar pilot studies have been carried out among trainers in four other regions on England. Separate reports have been prepared for each of the five regions, together with a summary report comparing the findings among the regions. The pilot studies were funded by the DHSS and carried out by staff of the Health Services Research Unit at the University of Kent at Camterbury

    Structural characterization of YBa(2)Cu(3)O(7)/Y(2)O(3) composite films

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    Using 4-circle x-ray diffraction and transmission electron microscopy we have studied the microstructure and in-plane orientation of the phases present in thin film composite mixtures of YBa(2)Cu(3)O(7) and Y(2)O(3). We see a high degree of in-plane orientation and have verified a previous prediction for the in-plane order of Y(2)BaCuO(5) on (110) MgO. Transmission electron microscopy shows the composite films to be a mixture of two phases, with YBCO grain sizes of 1 micron. We have also compared our observations of the in-plane order to the predictions of a modified near coincidence site lattice model.Comment: To be published in Journal of Materials Research, (4 pages, 4 jpeg figures

    Radar scattering from desert terrains, Pisgah/Lavic Region, California: Implications for Magellan

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    A major component of the 1988 Mojave Field Experiment involved the simultaneous acquisition of quad-polarization multifrequency airborne Synthetic Aperture Radar (SAR) imaging radar data and ground measurements thought to be relevant to the radar scattering behavior of a variety of desert surfaces. In preparation for the Magellan mission to Venus, the experiment was designed to explore the ability of SAR to distinguish types of geological surfaces, and the effects of varying incidence angles on the appearance of such surfaces. The airborne SAR system acquired images at approx. 10 m resolution, at 3 incidence angles (30, 40, 50 degs) and at 3 wavelengths (P:68 cm, L:24 cm, C:5.6 cm). The polarimetric capabilities of the instrument allow the simulation of any combination of transmit and receive polarizations during data reduction. Calibrated trihedral corner reflectors were deployed within each scene to permit absolute radiometric calibration of the image data. Initial analyses of this comprehensive radar data set is reported, with emphasis on implications for interpretation of Magellan data

    Advanced flight deck/crew station simulator functional requirements

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    This report documents a study of flight deck/crew system research facility requirements for investigating issues involved with developing systems, and procedures for interfacing transport aircraft with air traffic control systems planned for 1985 to 2000. Crew system needs of NASA, the U.S. Air Force, and industry were investigated and reported. A matrix of these is included, as are recommended functional requirements and design criteria for simulation facilities in which to conduct this research. Methods of exploiting the commonality and similarity in facilities are identified, and plans for exploiting this in order to reduce implementation costs and allow efficient transfer of experiments from one facility to another are presented

    Results of literature search on dielectric properties and electron interaction phenomena related to spacecraft charging

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    The objective of the literature search was to determine the required material properties and electron interaction parameters needed for modeling charge buildup and breakdown in insulators. A brief overview of the results of the literature search is given. A partial list of the references covered is included in a bibliography. Although inorganic insulators were also considered in the search, coverage is limited to the organics, primarily Kapton and Teflon

    Solar cell radiation response near the interface of different atomic number materials

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    The response of cobalt 60 irradiated N/P silicon solar cells was measured as a function of the atomic number of the medium adjacent to the cell and the direction of the gamma ray beam. The interpositioning of various thicknesses of aluminum between the adjacent material and the cell had the effect of moving the cell to various locations in an approximate monatomic numbered medium. Using this technique the solar cell response was determined at various distances from the interface for gold and beryllium. The results were compared with predictions based upon ionization chamber measurements of dose perturbations in aluminum and found to agree within five percent. Ionization chamber data was then used to estimate the influence of various base contact materials

    Automated clinical system for chromosome analysis

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    An automatic chromosome analysis system is provided wherein a suitably prepared slide with chromosome spreads thereon is placed on the stage of an automated microscope. The automated microscope stage is computer operated to move the slide to enable detection of chromosome spreads on the slide. The X and Y location of each chromosome spread that is detected is stored. The computer measures the chromosomes in a spread, classifies them by group or by type and also prepares a digital karyotype image. The computer system can also prepare a patient report summarizing the result of the analysis and listing suspected abnormalities

    The Redshift Distribution of FIRST Radio Sources at 1 mJy

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    We present spectra for a sample of radio sources from the FIRST survey, and use them to define the form of the redshift distribution of radio sources at mJy levels.We targeted 365 sources and obtained 46 redshifts (13 per cent of the sample). We find that our sample is complete in redshift measurement to R ∼18.6\sim 18.6, corresponding to z∼0.2z\sim 0.2. Early-type galaxies represent the largest subset (45 per cent) of the sample and have redshifts 0.15\la z \la 0.5 ; late-type galaxies make up 15 per cent of the sample and have redshifts 0.05\la z \la 0.2; starbursting galaxies are a small fraction (∼6\sim 6 per cent), and are very nearby (z\la 0.05). Some 9 per cent of the population have Seyfert1/quasar-type spectra, all at z\ga 0.8, and there are 4 per cent are Seyfert2 type galaxies at intermediate redshifts (z∼0.2z\sim 0.2). Using our measurements and data from the Phoenix survey, we obtain an estimate for N(z)N(z) at S1.4GHz≥1S_{1.4 \rm {GHz}}\ge 1 mJy and compare this with model predictions. At variance with previous conclusions, we find that the population of starbursting objects makes up \la 5 per cent of the radio population at S ∼1\sim 1 mJy.Comment: 20 pages, sumbitted to MNRA

    Effect of Gravitational Lensing on Measurements of the Sunyaev-Zel'dovich Effect

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    The Sunyaev-Zel'dovich (SZ) effect of a cluster of galaxies is usually measured after background radio sources are removed from the cluster field. Gravitational lensing by the cluster potential leads to a systematic deficit in the residual intensity of unresolved sources behind the cluster core relative to a control field far from the cluster center. As a result, the measured decrement in the Rayleigh-Jeans temperature of the cosmic microwave background is overestimated. We calculate the associated systematic bias which is inevitably introduced into measurements of the Hubble constant using the SZ effect. For the cluster A2218, we find that observations at 15 GHz with a beam radius of 0'.4 and a source removal threshold of 100 microJy underestimate the Hubble constant by 6-10%. If the profile of the gas pressure declines more steeply with radius than that of the dark matter density, then the ratio of lensing to SZ decrements increases towards the outer part of the cluster.Comment: 11 pages, 3 figures, submitted to ApJ
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