59,572 research outputs found

    A Note on the Importance of Weak Convergence Rates for SPDE Approximations in Multilevel Monte Carlo Schemes

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    It is a well-known rule of thumb that approximations of stochastic partial differential equations have essentially twice the order of weak convergence compared to the corresponding order of strong convergence. This is already known for many approximations of stochastic (ordinary) differential equations while it is recent research for stochastic partial differential equations. In this note it is shown how the availability of weak convergence results influences the number of samples in multilevel Monte Carlo schemes and therefore reduces the computational complexity of these schemes for a given accuracy of the approximations.Comment: 16 pages, 3 figures, updated to version published in the Proceedings of MCQMC1

    Commissioning of the 1.4 Mev/u High Current Heavy Ion Linac at Gsi

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    The disassembly of the Unilac prestripper linac of the Wideroe type took place at the beginning of 1999. An increase of more than two orders of magnitude in particle number for the most heavy elements in the SIS had to be gained. Since that time the new High Current Injector (HSI) consisting of H-type RFQ and DTL-structures for dual beam operation was installed and successfully commissioned. The High Charge Injector (HLI) supplied the main linac during that time. Simultaneously conditioning and running in of the rf-transmitters and rf-structures were done. The HSI commissioning strategy included beam investigation after each transport and acceleration section, using a versatile diagnostic test stand. Results of the extensive commissioning measurements (e.g. transverse emittance, bunch width, beam transmission) behind LEBT, RFQ, Super Lens, IH tank I and II and stripping section will be discussed. An 40Ar1+ beam coming from a MUCIS ion source was used to fill the linac up to the theoretical space charge limit. Routine operation started in November 1999.Comment: Linac 2000, FR201, 5 pages, 8 figure

    Sellars on Descartes

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    This essay is a critical assessment of Sellars' interpretation and criticism of Descartes. It argues that Sellars made several mistakes in his view of Descartes, although the general thrust of his critique is sound

    Kelly\u27s Rock Of Gibralter

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    Kelly, Kentucky! Stop here three minutes. Next stop Hopkinsville. A town like a million others. Hay, feed and grain shed and a dinky little station. A small boy, whose pants were patched with flesh, and a dog mooching on the platform. Everyone on the day coach gives Kelly one look and one sigh and pulls in his neck. Just another three-minute stop

    The Rationality of Humility

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    In this paper I explore humility as a paradigm, with reference to recent debates over the morality and rationality of emotions, and to the relation between religion and emotion. In Ancient Greek ethics, humility did not yet play a role; with the rise of Christianity, however, it becomes one of the cardinal virtues -- only to disappear again with the onset of modernity. Against a culture-pessimistic interpretation of this development, this article begins by characterising the relation between virtue and emotion, before reconstructing the inner rationality of humility and showing how it can be traced through several transformations to a modern ethics of responsibility. Against this background, possible manifestations of the humble attitude in the present are made plausible

    Black hole masses in active galaxies

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    This contribution reviews two topics of current interest in the study of black hole demographics in active galaxies: Can the stellar velocity dispersions of quasar host galaxies be measured? And can we constrain the black hole mass function below 10^6 M_⊙

    Healthy Steps at 15: The Past and Future of an Innovative Preventive Care Model for Young Children

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    Evaluates a model for preventive pediatric care for children up to age 3 that relies on mid-level specialists, including the program's spread, operating costs, funding, challenges, and potential effects of healthcare reform. Includes site profiles