2,998 research outputs found

    Improving health-related quality of life in single-sided deafness: a systematic review and meta-analysis

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    Unilateral severe-to-profound hearing loss, or single-sided deafness (SSD), impairs listening abilities supported by the use of two ears, including speech perception in background noise and sound localisation. Hearing-assistive devices can aid listening by re-routing sounds from the impaired to the non-impaired ear or by restoring input to the impaired ear. A systematic review of the literature examined the impact of hearing-assistive devices on the health-related quality of life (HRQoL) of adults with SSD as measured using generic and disease-specific instruments. A majority of studies used observational designs, and the quality of the evidence was low to moderate. Only two studies used generic instruments. A mixed-effect meta-analysis of disease-specific measures suggested that hearing-assistive devices have a small-to-medium impact on HRQoL. The Speech, Spatial and Qualities of Hearing Scale and the Health Utilities Index Mark 3 (HUI3) were identified as instruments that are sensitive to device-related changes in disease-specific and generic HRQoL, respectively

    Computational Electromagnetic Modeling of SansEC(Trade Mark) Sensors

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    This paper describes the preliminary effort to apply computational design tools to aid in the development of an electromagnetic SansEC resonant sensor composite materials damage detection system. The computational methods and models employed on this research problem will evolve in complexity over time and will lead to the development of new computational methods and experimental sensor systems that demonstrate the capability to detect, diagnose, and monitor the damage of composite materials and structures on aerospace vehicles

    Transport and Reaction Processes in Soil

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    In order to register agrochemicals in Europe it is necessary to have a detailed understanding of the processes in the environment that break down agrochemicals. The existing framework for environmental assessment includes a consideration of soil water movement and microbial breakdown of products in soil and these processes are relatively understood and represented in models. However the breakdown of agrochemicals by the action of light incident on the soil surface by a process termed photolysis is not so well represented in models of environmental fate. The problem brought by Syngenta (one of the worlds leading agrochemical companies) to the workshop was how to include the effects of light degradation of chemicals into predictive models of environmental fate. Photolysis is known to occur in a very thin layer at the surface of soil. The workshop was asked to consider how the very rough nature of the upper surface of a ploughed field might affect the degradation of chemicals by sunlight. The discussions were directed down two avenues: - firstly to determine how the very small distances over which photolysis occurs might be adequately incorporated into models of transport in soils and, - secondly to consider how the rough surface might modify the illumination of the surface and hence alter degradation. The rate of degradation by photolysis is measured in the laboratory by illuminating a thin, typically about 1 or 2 mm, layer of soil with very strong xenon lamps. The amount of chemical is measured at various intervals and is fitted to a first-order process. Field experiments where the chemical is sprayed on a bare field show evidence of photolysis indicated by biphasic degradation patterns and the presence of breakdown products only formed by photolysis. This report addresses methods for mathematically modelling the action of photolysis on particular relevant chemical species. We start with a general discussion of mechanisms that transport chemicals within soil §2. There is an existing computational model exploited by Syngenta for such modelling and we discuss how this performs and the predictions that can be derived using it §3. The particular mechanism of photolysis is then considered. One aspect of this mechanism that is investigated is how the roughness of the surface of the soil could be adequately incorporated into the modelling. Some results relating to this are presented §4.2. Some of the original experimental data used to derive aspects of the model of photolysis are revisited and a simple model of the process presented and shown to fit the data very well §5. By considering photolysis with a constant diffusion coefficient various analytical results are derived and general behaviour of the system outlined. This simple model is then applied to real field-based data and shown to give very good fit when simply extended to account for the moisture variations by utilising moisture dependent diffusion coefficients derived from the existing computational model §5.3. Some consequences of the simple model are then discussed §6

    Vestibular Contributions to Human Memory

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    The vestibular system is an ancient structure which supports the detection and control of self-motion. The pervasiveness of this sensory system is evidenced by the diversity of its anatomical projections and the profound impact it has on a range of higher level functions, particularly spatial memory. The aim of this thesis was to better characterise the association between the vestibular system and human memory; while many studies have explored this association from a biological perspective few have done so from a psychological one. In Chapter 1, evidence was drawn from 101 neuro-otology patients to show that vestibular dysfunction can exert a direct negative effect on memory and allied cognitive processes, independently of age and comorbid psychiatric and fatigue symptoms. In Chapters 3 and 4, the separability of these cognitive, psychiatric and fatigue symptoms was further demonstrated in eight traumatic brain injury patients who, following a programme of daily vestibular stimulation, showed cognitive improvement and electrophysiological modulation in the absence of psychiatric or fatigue-related changes. Finally in Chapter 5, a set of normative experiments indicated that, beyond any generic arousal effect (unspecific to any particular cognitive process), visual memory can utilise temporally coincident vestibular activation to help individuate one memory from another. Together these findings help clarify the range of and manner in which vestibular signals interact with visual short-term memory and allied cognitive processes. The findings also have clinical implications for the diagnosis and management of vestibular, neuropsychiatric and amnesic conditions

    Open Circuit Resonant (SansEC) Sensor Technology for Lightning Mitigation and Damage Detection and Diagnosis for Composite Aircraft Applications

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    Traditional methods to protect composite aircraft from lightning strike damage rely on a conductive layer embedded on or within the surface of the aircraft composite skin. This method is effective at preventing major direct effect damage and minimizes indirect effects to aircraft systems from lightning strike attachment, but provides no additional benefit for the added parasitic weight from the conductive layer. When a known lightning strike occurs, the points of attachment and detachment on the aircraft surface are visually inspected and checked for damage by maintenance personnel to ensure continued safe flight operations. A new multi-functional lightning strike protection (LSP) method has been developed to provide aircraft lightning strike protection, damage detection and diagnosis for composite aircraft surfaces. The method incorporates a SansEC sensor array on the aircraft exterior surfaces forming a "Smart skin" surface for aircraft lightning zones certified to withstand strikes up to 100 kiloamperes peak current. SansEC sensors are open-circuit devices comprised of conductive trace spiral patterns sans (without) electrical connections. The SansEC sensor is an electromagnetic resonator having specific resonant parameters (frequency, amplitude, bandwidth & phase) which when electromagnetically coupled with a composite substrate will indicate the electrical impedance of the composite through a change in its resonant response. Any measureable shift in the resonant characteristics can be an indication of damage to the composite caused by a lightning strike or from other means. The SansEC sensor method is intended to diagnose damage for both in-situ health monitoring or ground inspections. In this paper, the theoretical mathematical framework is established for the use of open circuit sensors to perform damage detection and diagnosis on carbon fiber composites. Both computational and experimental analyses were conducted to validate this new method and system for aircraft composite damage detection and diagnosis. Experimental test results on seeded fault damage coupons and computational modeling simulation results are presented. This paper also presents the shielding effectiveness along with the lightning direct effect test results from several different SansEC LSP and baseline protected and unprotected carbon fiber reinforced polymer (CFRP) test panels struck at 40 and 100 kiloamperes following a universal common practice test procedure to enable damage comparisons between SansEC LSP configurations and common practice copper mesh LSP approaches. The SansEC test panels were mounted in a LSP test bed during the lightning test. Electrical, mechanical and thermal parameters were measured during lightning attachment and are presented with post test nondestructive inspection comparisons. The paper provides correlational results between the SansEC sensors computed electric field distribution and the location of the lightning attachment on the sensor trace and visual observations showing the SansEC sensor's affinity for dispersing the lightning attachment

    Growing Up in Civil Rights Richmond: A Community Remembers

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    Published on the occasion of the exhibition Growing Up in Civil Rights Richmond: A Community Remembers, Joel and Lila Harnett Museum of Art, University of Richmond Museums, January 17 to May 10, 2019. Organized by the University of Richmond Museums, the exhibition was developed by Ashley Kistler, independent curator, and Laura Browder, Tyler and Alice Haynes Professor of American Studies, University of Richmond. The exhibition, related programs, and publication are made possible in part with funds from the Louis S. Booth Arts Fund and with support from the University’s Cultural Affairs Committee. The printed exhibition catalogue was made possible in part with support from the Elizabeth Firestone Graham Foundation. Published by University of Richmond Museums, Richmond, Virginia. Edited by N. Elizabeth Schlatter, University of Richmond Museums, and Ashley Kistler, independent curator. Designed by DELANO Creative, Richmond, Virginia Printed by Worth Higgins & Associates Inc., Richmond, Virginia. Cover: Brian Palmer (American, born 1964), Deborah Taylor, Franklin Military Academy (formerly East End High School), 2017, archival inkjet print on paper, 30 x 40 inches, lent courtesy of the artist.https://scholarship.richmond.edu/exhibition-catalogs/1006/thumbnail.jp

    A Hindbrain Inhibitory Microcircuit Mediates Vagally-Coordinated Glucose Regulation

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    Neurons in the brainstem dorsal vagal complex integrate neural and humoral signals to coordinate autonomic output to viscera that regulate a variety of physiological functions, but how this circuitry regulates metabolism is murky. We tested the hypothesis that premotor, GABAergic neurons in the nucleus tractus solitarius (NTS) form a hindbrain micro-circuit with preganglionic parasympathetic motorneurons of the dorsal motor nucleus of the vagus (DMV) that is capable of modulating systemic blood glucose concentration. In vitro, neuronal activation or inhibition using either excitatory or inhibitory designer receptor exclusively activated by designer drugs (DREADDs) constructs expressed in GABAergic NTS neurons increased or decreased, respectively, action potential firing of GABAergic NTS neurons and downstream synaptic inhibition of the DMV. In vivo, DREADD-mediated activation of GABAergic NTS neurons increased systemic blood glucose concentration, whereas DREADD-mediated silencing of these neurons was without effect. The DREADD-induced hyperglycemia was abolished by blocking peripheral muscarinic receptors, consistent with the hypothesis that altered parasympathetic drive mediated the response. This effect was paralleled by elevated serum glucagon and hepatic phosphoenolpyruvate carboxykinase 1 (PEPCK1) expression, without affecting insulin levels or muscle metabolism. Activity in a hindbrain inhibitory microcircuit is sufficient to modulate systemic glucose concentration, independent of insulin secretion or utilization
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