4,316 research outputs found

    The comparison of hearing loss among diabetic and non-diabetic patients

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    Introduction: The prevalence of Diabetes Mellitus is steadily increasing. This is a multi- systemic abnormality, causing side- effects which are mainly irreversible. Hearing loss is one of the common symptoms, and there are many studies, with contradictory results. Aim of this study was to compare the hearing loss among diabetic with non- diabetic patients. Material and Methods: In this study 50 diabetic patients were chosen randomly from those overt diabetic patients referred to the Diabetes clinic in Gorgan hospital northern Iran, 50 other patients who referred to the 5th Azar hospital, with any other ENT complaint were also randomly chosen as control group. The case and control groups were matched. Demographic questionnaires were filled for each subjects in case and control groups, and those with intervening factors were omitted from this study. Data were analyzed using SPSS. Results: In this study 66% and 34% of participants were men and women respectively. The age distribution of the patient were 15-75 years. The hearing loss among diabetic patients and non- diabetic subjects were 16% and 5% respectively, which showed that the diabetic patient has3.2 times more possibility to acquire hearing problem. It was also shown, that there was a direct correlation between increasingage and hearing loss. More women are at risk, of getting hearingloss than men. The hearing loss also has a correlation with the duration of disease onset and the consumption of Glibanclamid. Conclusion The careful periodical assessment of hearing loss, and the application of hearing facilities to improve the qualityof diabetic patients life is recommended due to chronic and irreversible Symptom of the disease

    Similarities Between Classical Timelike Geodesics in a Naked Reissner-Nordstrom Singularity Background and the Behaviour of Electrons in Quantum Theory

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    It is generally assumed that naked singularities must be physically excluded, as they could otherwise introduce unpredictable influences in their future null cones. Considering geodesics for a naked Reissner-Nordstrom singularity, it is found that the singularity is effectively clothed by its repulsive nature. Regarding electron as naked singularity, the size of the clothed singularity (electron) turns out to be classical electro-magnetic radius of the electron, to an observer falling freely from infinity, initially at rest. The size shrinks for an observer falling freely from infinity, with a positive initial velocity. For geodetic parameters corresponding to negative energy there are trapped geodesics. The similarity of this picture with that arising in the Quantum Theory is discussed.Comment: 8 pages, 6 figure

    On computing joint invariants of vector fields

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    A constructive version of the Frobenius integrability theorem -- that can be programmed effectively -- is given. This is used in computing invariants of groups of low ranks and recover examples from a recent paper of Boyko, Patera and Popoyvich \cite{BPP}

    Time-resolved terahertz dynamics in thin films of the topological insulator Bi2_{2}Se3_3

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    We use optical pump--THz probe spectroscopy at low temperatures to study the hot carrier response in thin Bi2_2Se3_3 films of several thicknesses, allowing us to separate the bulk from the surface transient response. We find that for thinner films the photoexcitation changes the transport scattering rate and reduces the THz conductivity, which relaxes within 10 picoseconds (ps). For thicker films, the conductivity increases upon photoexcitation and scales with increasing both the film thickness and the optical fluence, with a decay time of approximately 5 ps as well as a much higher scattering rate. These different dynamics are attributed to the surface and bulk electrons, respectively, and demonstrate that long-lived mobile surface photo-carriers can be accessed independently below certain film thicknesses for possible optoelectronic applications.Comment: 4+ pages, 3 figures. Submitte

    Framework for better living with HIV in England

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    Duration: April 2007 - May 2009 Sigma Research was funded by Terrence Higgins Trust to co-ordinate the development of a framework to address the health, social care, support and information needs of people with diagnosed HIV in England. It has now been published as the Framework for better living with HIV in England. The over-arching goal of the framework is that all people with diagnosed HIV in England "are enabled to have the maximum level of health, well-being, quality of life and social integration". In its explanation of how this should occur the document presents a road map for social care, support and information provision to people with diagnosed HIV in England. By establishing and communicating aims and objectives, the framework should build consensus and provide a means to establish how interventions could be prioritised and coordinated. The key drivers for the framework were clearly articulated ethical principles, agreed by all those who sign up to it, and an inclusive social development / health promotion approach. Sigma Research worked on the framework with a range of other organisations who sent representatives to a Framework Development Group (see below for membership). The framework is evidence-based and seeks to: Promote and protect the rights and well-being of all people with HIV in England. Maximise the capacity of individuals and groups of people with HIV to care for, advocate and represent themselves effectively. Improve and protect access to appropriate information, social support, social care and clinical services. Minimise social, economic, governmental and judicial change detrimental to the health and well being of people with HIV. Alongside the development of the framework, Sigma Research undertook a national needs assessment among people with diagnosed HIV across the UK called What do you need?. These two projects informed and supported each other. Framework Development Group included: African HV Policy Network Black Health Agency George House Trust NAM NAT (National AIDS Trust) Positively Women Terrence Higgins Trus

    Passive radiative "thermostat" enabled by phase-change photonic nanostructures

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    A thermostat senses the temperature of a physical system and switches heating or cooling devices on or off, regulating the flow of heat to maintain the system's temperature near a desired setpoint. Taking advantage of recent advances in radiative heat transfer technologies, here we propose a passive radiative "thermostat" based on phase-change photonic nanostructures for thermal regulation at room temperature. By self-adjusting their visible to mid-IR absorptivity and emissivity responses depending on the ambient temperature, the proposed devices use the sky to passively cool or heat during day-time using the phase-change transition temperature as the setpoint, while at night-time temperature is maintained at or below ambient. We simulate the performance of a passive nanophotonic thermostat design based on vanadium dioxide thin films, showing daytime passive cooling (heating) with respect to ambient in hot (cold) days, maintaining an equilibrium temperature approximately locked within the phase transition region. Passive radiative thermostats can potentially enable novel thermal management technologies, e.g. to moderate diurnal temperature in regions with extreme annual thermal swings

    High-Temperature Refractory Metasurfaces for Solar Thermophotovoltaic Energy Harvesting

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    Solar energy promises a viable solution to meet the ever-increasing power demand by providing a clean, renewable energy alternative to fossil fuels. For solar thermophotovoltaics (STPV), high-temperature absorbers and emitters with strong spectral selectivity are imperative to efficiently couple solar radiation into photovoltaic cells. Here, we demonstrate refractory metasurfaces for STPV with tailored absorptance and emittance characterized by in-situ high-temperature measurements, featuring thermal stability up to at least 1200 C. Our tungsten-based metasurface absorbers have close-to-unity absorption from visible to near infrared and strongly suppressed emission at longer wavelengths, while our metasurface emitters provide wavelength-selective emission spectrally matched to the band-edge of InGaAsSb photovoltaic cells. The projected overall STPV efficiency is as high as 18% when employing a fully integrated absorber/emitter metasurface structure, much higher than those achievable by stand-alone PV cells. Our work opens a path forward for high-performance STPV systems based on refractory metasurface structures.Comment: Preprint, 31 pages, 5 figures, 5 supporting figure
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