35,982 research outputs found

    A global protocol for monitoring of coral bleaching

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    Coral bleaching and subsequent mortality represent a major threat to the future health and productivity of coral reefs. However a lack of reliable data on occurrence, severity and other characteristics of bleaching events hampers research on the causes and consequences of this important phenomenon. This article describes a global protocol for monitoring coral bleaching events, which addresses this problem and can be used by people with different levels of expertise and resources

    The Limit Behavior Of The Trajectories of Dissipative Quadratic Stochastic Operators on Finite Dimensional Simplex

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    The limit behavior of trajectories of dissipative quadratic stochastic operators on a finite-dimensional simplex is fully studied. It is shown that any dissipative quadratic stochastic operator has either unique or infinitely many fixed points. If dissipative quadratic stochastic operator has a unique point, it is proven that the operator is regular at this fixed point. If it has infinitely many fixed points, then it is shown that ω\omega- limit set of the trajectory is contained in the set of fixed points.Comment: 14 pages, accepted in Difference Eq. App

    Evaluation of the electrochemical O2 concentrator as an O2 compressor

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    A program was successfully completed to analytically and experimentally evaluate the feasibility of using an electrochemical oxygen (O2) concentrator as an O2 compressor. The electrochemical O2 compressor (EOC) compresses 345 kN/sq m (50 psia) O2 generated on board the space vehicle by the water electrolysis subsystem (WES) in a single stage to 20,700 kN/sq m (3000 psia) to refill spent extravehicular equipment O2 bottles and to eliminate the need for high pressure O2 storage. The single cell EOC designed, fabricated, and used for the feasibility testing is capable of being tested at O2 pressures up to 41,400 kN/sq m (6000 psia). A ground support test facility to test the EOC cell was designed, fabricated, and used for the EOC feasibility testing. A product assurance program was established, implemented, and maintained which emphasized safety and materials compatibility associated with high pressure O2 operation. A membrane development program was conducted to develop a membrane for EOC application. Data obtained using a commercially available membrane were used to guide the development of the membranes fabricated specifically for an EOC. A total of 15 membranes were fabricated

    Development of Thermal Testing Techniques at High Solar Intensities Final Report, 13 Aug. 1965 - 13 May 1967

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    Solar energy simulation techniques for testing spacecraft thermal performanc

    Lump Sum versus Annuity: Choices of Kentucky Farmers during the Tobacco Buyout Program

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    Our study uses the data collected during the implementation of the tobacco buyout program in Kentucky to evaluate how rural households, diverse in income, age, family structure, location, education level, and other characteristics, made a choice between annuities and a lump-sum payment. Subjects in our field experiment did not have to retire or change their employment, as did subjects in many field studies of the choice between annuities and lump-sum payments, which allowed us to evaluate the relationship between the option choice and a decision whether to exit the tobacco market. Our results suggest that while discounted utility theory gives acceptable predictions of the farmers’ behavior, other factors have to be taken into consideration. First, there are consistent biases that describe individual intertemporal behavior, such as availability bias or acquiescence bias. Second, there is a certain degree of heterogeneity in individual intertemporal preferences that correlates with their personal characteristics, such as education and production status. Third, our analysis revealed that the decision to exit the tobacco market positively correlated with the decision to take a lump-sum payment.annuity, family business system, intertemporal choice, lump sum, tobacco buyout, Agribusiness, Consumer/Household Economics, Institutional and Behavioral Economics, Marketing, G11, H31, J10,

    An X-ray survey of 9 algol systems

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    The observed X-ray luminosities seen from an Einstein survey of nine Algol like systems are similar to those found by Pallavicini, et al. (1981) for single or widely separated rapidly rotating late stars, but fall an order of magnitude below those seen from RS CVn stars with similar orbital periods and spectral types. It is concluded that the X-ray emission is most probably associated with a hot coronae surrounding the secondary. Possible explanations for the lower luminosity of the Algol systems relative to the RS CVn systems are considered

    The 805s X-ray pulsar H2252-035

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    The X-ray flux from the 3.6 hr binary system H2252-035 is shown to be modulated at a period of 805s. The spectrum is consistent with either a 1.4 photon index power law or 20 keV thermal model. A 560t0r-350 eV equivalent width iron line is seen at approximately 6.7 keV. The possibility that this system contains a slowly rotating neutron star is discussed
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