2,374 research outputs found

    Bayesians Can Learn From Old Data

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    In a widely-cited paper, Glymour (Theory and Evidence, Princeton, N. J.: Princeton University Press, 1980, pp. 63-93) claims to show that Bayesians cannot team from old data. His argument contains an elementary error. I explain exactly where Glymour went wrong, and how the problem should be handled correctly. When the problem is fixed, it is seen that Bayesians, just like logicians, can indeed learn from old data.Astronom

    Astrometry with the ATF

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    A detailed study of the effects of gravitational radiation on the relative positions of objects was carried out with the hope that astrometric detection of gravitational radiation might be possible. The results are discouraging. It would appear that narrow-field instruments in the Astrometric Telescope Facility (ATF) class are still several orders of magnitude less accurate than would be required for this very delicate kind of measurement. However, the situation changes considerably when wide-field instruments are considered. An instrument such as POINTS ought to be able to detect gravitational radiation at this level with ease. The list of bright quasars has been augmented. Of particular interest is the finding of quasars near two open clusters and one planetary nebula. These would be useful in determining absolute parallaxes of these objects

    Orbital theories of outer planet satellites

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    An analytical theory of Mimas and Tethys was developed, retaining terms which produce perturbations of the order of + or - 10 km. The theory uses a novel set of variables, and was developed with the Hori-Lie algorithm, using the algebraic manipulation language TRIGMAN. the perturbations were implemented by means of FORTRAN subroutines produced by the computer

    IGDS/TRAP Interface Program (ITIP). Software Design Document

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    The preliminary design of the IGDS/TRAP Interface Program (ITIP) is described. The ITIP is implemented on the PDP 11/70 and interfaces directly with the Interactive Graphics Design System and the Data Management and Retrieval System. The program provides an efficient method for developing a network flow diagram. Performance requirements, operational rquirements, and design requirements are discussed along with sources and types of input and destination and types of output. Information processing functions and data base requirements are also covered

    Jefferys Family Bible - Accession 1688

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    The Jefferys Family Bibles consists of two bibles belonging to the Black Family and extended family of Rock Hill, SC. The bible contains genealogical entries and family records dating from 1800 through 1972 relating primarily to the Jeffreys and Jackson Family line, but also includes some connections to the Gilbert Family, Smith Family, Williams Family, and West Family. Wthin the pages of the Bible were several newspaper clippings and obituaries, funeral programs, notes, and other material. The Jefferys Family can trace their York County roots to James Jeffreys (1800-1883) who is buried in Old Settlers Cemetery in York, SC. He was one of the first settlers of the area. He was originally from Island of Alderney in the English Channel and made his way to Yorkville, SC in 1821 when the town had but a couple hundred inhabitants.https://digitalcommons.winthrop.edu/manuscriptcollection_findingaids/2664/thumbnail.jp

    Bayesian Nonparametric Shrinkage Applied to Cepheid Star Oscillations

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    Bayesian nonparametric regression with dependent wavelets has dual shrinkage properties: there is shrinkage through a dependent prior put on functional differences, and shrinkage through the setting of most of the wavelet coefficients to zero through Bayesian variable selection methods. The methodology can deal with unequally spaced data and is efficient because of the existence of fast moves in model space for the MCMC computation. The methodology is illustrated on the problem of modeling the oscillations of Cepheid variable stars; these are a class of pulsating variable stars with the useful property that their periods of variability are strongly correlated with their absolute luminosity. Once this relationship has been calibrated, knowledge of the period gives knowledge of the luminosity. This makes these stars useful as "standard candles" for estimating distances in the universe.Comment: Published in at http://dx.doi.org/10.1214/11-STS384 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

    Equivalence of the perturbation theories of Hori and Deprit

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    Equivalence of perturbation theories of Hori and Deprit, based on Poisson brackets, and computer calculations through sixth orde

    IGDS/TRAP Interface Program (ITIP). Detailed Design Specification (DDS)

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    The software modules which comprise the IGDS/TRAP Interface Program are described. A hierarchical input processing output (HIPO) chart for each user command is given. The description consists of: (1) function of the user command; (2) calling sequence; (3) moduls which call this use command; (4) modules called by this user command; (5) IGDS commands used by this user command; and (6) local usage of global registers. Each HIPO contains the principal functions performed within the module. Also included with each function are a list of the inputs which may be required to perform the function and a list of the outputs which may be created as a result of performing the function

    Vacuum Energy: Cosmological Constant or Quintessence?

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    For a flat universe presently dominated by smooth energy, either cosmological constant (LCDM) or quintessence (QCDM), we calculate the asymptotic collapsed mass fraction as function of the present ratio of smooth energy to matter energy R0\mathcal R_0. Identifying the normalized collapsed fraction as a conditional probability for habitable galaxies, we observe that the observed present ratio R0∼2\mathcal R_0 \sim 2 is likely in LCDM, but more likely in QCDM. Inverse application of Bayes' Theorem makes the Anthropic Principle a predictive scientific principle: the data implies that the prior probability for R0\mathcal R_0 must be essentially flat over the anthropically allowed range. Interpreting this prior as a distribution over {\em theories} lets us predict that any future theory of initial conditions must be indifferent to R0\mathcal R_0. This application of the Anthropic Principle does not demand the existence of other universes.Comment: 17 pages AAS LATEX, including 2 tables, 3 figures (Postscript

    Advances in understanding basic mechanisms of epilepsy and seizures

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    AbstractSixty years ago the clinical neurophysiology of epilepsy had progressed to the stage that it posed questions that could be addressed by major advances in cellular electrophysiology made around the that time. However, it took about 25–30 years to build up serious momentum in understanding the mechanisms of epileptic discharges. Over the past 2–3 decades developments in pharmacology and molecular biology have substantially increased the depth and complexity of our insights into the nervous system in general and the epileptic brain in particular. One of the biggest advances in our understanding of the brain is in its plasticity in the adult – that is its ability to modify its structure and function. The current state of play is that for most chronic epileptic foci it is possible to identify multiple differences from normal brain tissue in both the structure and function of neurons, neuronal networks and glia. This review will chart some of this progress to give an idea of the pace of advances over the decades
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