26,309 research outputs found

    Dying to go to court: demanding a legal remedy to end-of-life uncertainty

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    Visual Attention to Radar Displays

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    A model is described which predicts the allocation of attention to the features of a radar display. It uses the growth of uncertainty and the probability of near collision to call the eye to a feature of the display. The main source of uncertainty is forgetting following a fixation, which is modelled as a two dimensional diffusion process. The model was used to predict information overload in intercept controllers, and preliminary validation obtained by recording eye movements of intercept controllers in simulated and live (practice) interception

    Spatial imaging of modifications to fluorescence lifetime and intensity by individual Ag nanoparticles

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    Highly ordered periodic arrays of silver nanoparticles have been fabricated which exhibit surface plasmon resonances in the visible spectrum. We demonstrate the ability of these structures to alter the fluorescence properties of vicinal dye molecules by providing an additional radiative decay channel. Using fluorescence lifetime imaging microscopy (FLIM), we have created high resolution spatial maps of the molecular lifetime components; these show an order of magnitude increase in decay rate from a localized volume around the nanoparticles, resulting in a commensurate enhancement in the fluorescence emission intensity.Comment: 3 pages, 2 figures, submitted Applied Physics Letter

    Plasmonic engineering of metal nanoparticles for enhanced fluorescence and Raman scattering

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    We have investigated the effects of tuning the localized surface plasmon resonances (LSPRs) of silver nanoparticles on the fluorescence intensity, lifetime, and Raman signal from nearby fluorophores. The presence of a metallic structure can alter the optical properties of a molecule by increasing the excitation field, and by modifying radiative and non-radiative decay mechanisms. By careful choice of experimental parameters we have been able to decouple these effects. We observe a four-fold increase in fluorescence enhancement and an almost 30-fold increase in decay rate from arrays of Ag nanoparticles, when the LSPR is tuned to the emission wavelength of a locally situated fluorophore. This is consistent with a greatly increased efficiency for energy transfer from fluorescence to surface plasmons. Additionally, surface enhanced Raman scattering (SERS) measurements show a maximum enhancement occurs when both the incident laser light and the Raman signal are near resonance with the plasmon energy. Spatial mapping of the SERS signal from a nanoparticle array reveals highly localized differences in the excitation field resulting from small differences in the LSPR energy.Comment: Submitted to Plasmonics (Springer

    Photosynthetic Gas Exchange in the Closed Ecosystem for Space. Phase II, Part III. Screening for Thermophilic Algae and Mutation Studies

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    An algal screening and mutation study was undertaken to obtain algae superior to Chlorella 71105 for use in a photosynthetic gas exchanger. Of the forty-four thermophilic algae studied, eighteen appeared to have growth rates as great as Chlorella 71105. Optimization of the physical and chemical environments of these strains is recommended as a way to further improve growth rates and concomitant oxygen production. The mutation study revealed that Chlorella 71105 is relatively resistant to germicidal ultraviolet radiation. No high temperature mutants of Chlorella 71105 were found

    Investigations on Deposit Formation in the Holes of Diesel Injector Nozzles

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    Current developments in fuels and emissions regulations are resulting in an increasingly severe operating environment for diesel fuel injection systems. The formation of deposits within the holes or on the outside of the injector nozzle can affect the overall system performance. The rate of deposit formation is affected by a number of parameters, including operating conditions and fuel composition. For the work reported here an accelerated test procedure was developed to evaluate the relative importance of some of these parameters in a high pressure common rail fuel injection system. The resulting methodology produced measurable deposits in a custom made injector nozzle on a single cylinder engine. The results indicate that fuels containing 30%v/v and 100% Fatty Acid Methyl Ester (FAME), that does not meet EN 14214 produced more deposit than an EN590 petroleum diesel fuel. Overall, the addition of zinc to the fuel had the biggest effect on deposit formation and resulted in a 12.2% decrease in Indicated Mean Effective Pressure (IMEP). The effects of zinc were unexpectedly reduced when it was added to fuel containing 30%v/v biodiesel. Reducing the common-rail pressure with 30%v/v biodiesel (no added zinc) increased the loss in IMEP. Raising the air and fuel temperatures by 40°C and 30°C respectively showed no bigger loss in IMEP. The results indicate that deposit formation may continue after engine shut down. © 2011 Society of Automotive Engineers of Japan, Inc. and SAE International

    Profitability and Long-term Survival of Community Banks: Evidence from Texas

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    This study examines the impact of distance among competing bank locations on market their pricing behavior. A general spatial autoregressive model that nests both spatial autoregressive and spatial error models is used to examine the impact of distance on pricing behavior of 686 non-metro banks in Texas. Results show that non-metro banks exercise market power in pricing their products. An increase in spatial competition may reduce profitability and challenge long term survival of small community based financial institutions.Financial Economics,

    Market Power in Non-Metro Banking

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    Banks in non-metropolitan areas compete in a spatially-differentiated environment. This paper estimates a structural model of the supply and demand of banking services in which pricing power depends on the distance between rival banks. A spatial econometric model finds that approximately 38.0% of economic surplus derives from spatial market power.Financial Economics,
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