2,646 research outputs found

    EFFECTS OF CHIGGER MITE (ACARI: TROMBICULIDAE) INFECTIONS ON AMEIVA (SQUAMATA: TEIIDAE) FROM THE ANGUILLA BANK

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    We examined 152 Ameiva plei from four sites on Anguilla and from Scrub Island, a nearby satellite, and 12 A. corax from Little Scrub Island, another Anguillian satellite, generated indices of condition by dividing mass (g) by SVL (mm), and quantified degrees of eutrombiculid chigger mite infections by measuring the total areas (mm2) of each lizard covered by one or more clusters of mites. Prevalence in infected A. plei (N = 77) varied significantly by site, but frequencies of infected males and females within sites did not differ signifi cantly. Indices of condition of infected and mite-free lizards did not differ significantly, nor was area covered by mites significantly correlated with condition, suggesting that mite infections are relatively asymptomatic. All Ameiva corax were infected, and area covered by mites was not significantly correlated with condition. Indices of condition for A. corax were signifi cantly lower than for infected A. plei, probably refl ecting the poorer condition of lizards occupying a food-deficient habitat

    Kinetic isolation tether experiment

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    Progress was made on the analysis of tether damping and on experimentation of the control system on the laboratory simulator. The damping analysis considers the dynamics of a long tether connecting two spacecraft in Earth orbit, one of the spacecraft having dominant mass. In particular, it considers the material damping of the tether. The results show that, with properly chosen tether material and braiding structure, longitudinal vibration of the tethered system is well damped. A particularly effective method of implementing attitude control for tethered satellites is to use the tether tension force to generate control torques by moving the tether attach point relative to the satellite center of mass. A scaled, one dimensional laboratory simulation of the KITE mission was built and preliminary experiments of the proposed attitude control system were performed. The simulator was built to verify theoretical predictions of attitude controllability, and to investigate the technological requirements in order to implement this concept. A detailed description of the laboratory apparatus is provided, and in addition, the results of the preliminary experiments are presented and discussed

    Australian mining industry: Credit and market tail risk during a crisis period

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    Industry risk is important to equities investors in determining portfolio mix. It is also important to lenders in managing credit portfolio risk. This article focuses on the mining industry in Australia, that country’s largest industry by exports. The study concentrates on extreme credit and market risk, to determine the riskiness of the mining industry relative to the broader market, with a focus on the Global Financial Crisis (GFC) period and the use tail risk metrics. These include Conditional Value at Risk (CVaR) for measuring market risk and Conditional Distance to Default (CDD) for measuring credit risk. Based on these metrics, the study finds market risk for mining shares to be higher than the broader market, but that the gap narrows during the crisis. From a credit perspective, despite higher volatility experienced by the mining industry, the default risk is lower than the broader market, due to the greater distance between mining entities’ asset and debt values

    New perspectives on bank risk in Malaysia

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    Stable banks in individual ASEAN countries are essential to the economic stability of the ASEAN region as these countries move towards the goal of greater financial integration in the region. This study comprehensively explores bank risk in Malaysia as compared to the ASEAN region over an 18-year period which includes the Asian and Global Financial Crises. Metrics used include non-performing loans (NPLs), conditional distance to default (CDD which focuses on tail risk of asset volatility and is the authors own measure of bank default based on an extension to the Merton distance to default (DD) model) and a tail risk (TR) measure being the difference between DD and CDD asset volatility. DD is usually applied to corporate customers of banks but has been applied in the literature to banks themselves, which is the approach used for CDD in this study. Multiple regression analysis is undertaken to assess the impact of CDD on returns. The regression and default results are compared between small and large banks. Malaysian banks were found to have consistently lower risk than the ASEAN region, with smaller Malaysian banks exhibiting greater risk than larger banks during non-crisis periods, but to a lesser degree during crisis periods

    Malaysian equities: A sector analysis of risk and normality

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    This study uses Value at Risk (VaR) and Conditional Value at Risk (CVaR) metrics to measure the relative riskiness of sectors for Malaysian equities. VaR is a widely used volatility measure, but only measures risk below a specified threshold, whereas CVaR looks at risk beyond that threshold. The study finds that the relative risk of sectors changes with changing economic circumstances as measured by VaR, but remains significantly the same as measured by CVaR. Parametric (normally distributed) measures of VaR are compared to nonparametric measures, and it is found, consistently across all sectors, that parametric measures are not suitable measures of volatility for Malaysian equities due to a large spread in tail risk

    The human side of automation: experience in clinical pharmacology

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