5,689 research outputs found

    Design of a Torque Current Generator for Strapdown Gyroscopes

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    The design, analysis, and experimental evaluation of an optimum performance torque current generator for use with strapdown gyroscopes, is presented. Among the criteria used to evaluate the design were the following: (1) steady-state accuracy; (2) margins of stability against self-oscillation; (3) temperature variations; (4) aging; (5) static errors drift errors, and transient errors, (6) classical frequency and time domain characteristics; and (7) the equivalent noise at the input of the comparater operational amplifier. The DC feedback loop of the torque current generator was approximated as a second-order system. Stability calculations for gain margins are discussed. Circuit diagrams are shown and block diagrams showing the implementation of the torque current generator are discussed

    From Egyptian Desert to Scottish Highlands – the radiographic study of a Twenty-Fifth Dynasty coffin and mummy bundle from the Perth Museum and Art Gallery, Scotland

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    Since 1936, the Perth Museum and Art Gallery, Scotland, has curated a wrapped ancient Egyptian human mummy within a wooden anthropoid coffin. In June 2013, funding was procured to transport the mummy and coffin to the University of Manchester for radiographic study, whereby information regarding the life and death of the individual was sought.The mummy and coffin were imaged using digital radiography (DR) and computed tomography (CT) at the Royal Manchester Children’s Hospital. The process revealed that the bundle contained the mummified remains of a single human individual, which had suffered extensive skeletal disruption. This paper focuses on the radiographic analysis of the artefact

    Detection of antibody-dependent complement mediated inactivation of both autologous and heterologous virus in primary HIV-1 infection

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    Specific CD8 T-cell responses to human immunodeficiency virus type 1 (HIV-1) are induced in primary infection and make an important contribution to the control of early viral replication. The importance of neutralizing antibodies in containing primary viremia is questioned because they usually arise much later. Nevertheless antienvelope antibodies develop simultaneously with, or even before, peak viremia. We determined whether such antibodies might control viremia by complement-mediated inactivation (CMI). In each of seven patients studied, antibodies capable of CMI appeared at or shortly after the peak in viremia, concomitantly with detection of virus-specific T-cell responses. The CMI was effective on both autologous and heterologous HIV-1 isolates. Activation of the classical pathway and direct viral lysis were at least partly responsible. Since immunoglobulin G (IgG)-antibodies triggered the CMI, specific memory B cells could also be induced by vaccination. Thus, consideration should be given to vaccination strategies that induce IgG antibodies capable of CMI

    Post-mortem restorations in ancient Egyptian animal mummies using imaging

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    Animal mummy bundles in museum collections are evaluated through the application of imaging and are categorised as true, those containing skeletal remains, and pseudo, those containing non-skeletal remains. True mummies exhibited a variety of compositions, and frequently contained less than one complete individual despite the external appearance; an explanation for which has been ancient forgery. The analysis of animal mummy bundles in the Ancient Egyptian Animal Bio Bank, University of Manchester, suggested that in some instances this explanation may be inaccurate. This paper discusses nine mummy bundles, which displayed a variety of post-mortem modifications interpreted in two ways: the necessity for physical completion and the concept of the mummy bundle (rather than the content) as the primary representation of the deceased

    GaN directional couplers for integrated quantum photonics

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    Large cross-section GaN waveguides are proposed as a suitable architecture to achieve integrated quantum photonic circuits. Directional couplers with this geometry have been designed with aid of the beam propagation method and fabricated using inductively coupled plasma etching. Scanning electron microscopy inspection shows high quality facets for end coupling and a well defined gap between rib pairs in the coupling region. Optical characterization at 800 nm shows single-mode operation and coupling-length-dependent splitting ratios. Two photon interference of degenerate photon pairs has been observed in the directional coupler by measurement of the Hong-Ou-Mandel dip with 96% visibility.Comment: 4 pages, 5 figure

    End stage renal disease and survival in people with diabetes:a national database linkage study

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    © The Author 2014. Published by Oxford University Press on behalf of the Association of Physicians. Funding This work was supported by the Wellcome Trust through the Scottish Health Informatics Programme (SHIP). The SHIP is collaboration between the Universities of Aberdeen, Dundee, Edinburgh, Glasgow and St Andrews and the Information Services Division of National Health Service National Service Scotland. Funding for diabetes register linkage and data extraction was provided by the Chief Scientist’s Office of the Scottish Government. The Scottish Diabetes Research Network receives financial support from National Health Services Research Scotland. The Scottish Renal Registry is funded by the Information Services Division of National Health Service National Services Scotland but relies heavily on the goodwill of the contributing renal units who spent a large amount time working with Scottish Renal Registry staff to ensure that the data held within the register are accurate and complete.Peer reviewedPublisher PD

    Mid-infrared Hall effect in thin-film metals: Probing the Fermi surface anisotropy in Au and Cu

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    A sensitive mid-infrared (MIR, 900-1100 cm-1, 112-136 meV) photo-elastic polarization modulation technique is used to measure simultaneously Faraday rotation and circular dichroism in thin metal films. These two quantities determine the complex AC Hall conductivity. This novel technique is applied to study Au and Cu thin films at temperatures down to 20 K and magnetic fields up to 8 T. The Hall frequency is consistent with band theory predictions. We report the first measurement of the MIR Hall scattering rate, which is significantly lower than that derived from Drude analysis of zero magnetic field MIR transmission measurements. This difference is qualitatively explained in terms of the anisotropy of the Fermi surface in Au and Cu.Comment: 14 pages of text, 5 figure
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