308 research outputs found

    Computability of Probability Distributions and Distribution Functions

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    We define the computability of probability distributions on the real line as well as that of distribution functions. Mutual relationships between the computability notion of a probability distribution and that of the corresponding distribution function are discussed. It is carried out through attempts to effectivize some classical fundamental theorems concerning probability distributions. We then define the effective convergence of probability distributions as an effectivization of the classical vague convergence. For distribution functions, computability and effective convergence are naturally defined as real functions. A weaker effective convergence is also defined as an effectivization of pointwise convergence

    Necessity to Measure PCBs and Organochlorine Pesticide Concentrations in Human Umbilical Cords for Fetal Exposure Assessment

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    Three types of tissue samples—umbilical cord (UC), umbilical cord serum (CS), and maternal serum (MS)—have often been used to assess fetal exposure to chemicals. In order to know the relationship of contamination between mothers and fetuses, we measured persistent chemicals in comparable sets of the three tissue samples. Also, we analyzed the association between the chemicals in maternal and fetal tissues to know which tissue is the best sample for fetal exposure assessment. On a wet basis, the chemical concentrations were of the order MS > CS > UC, except for some chemicals such as cis-chlordane and endosulfan. On a lipid basis, the concentrations in UC were nearly equal or often higher than in MS, but the concentrations in CS were usually lower than in others. Hexachlorocyclohexanes and penta-, hexa-, and heptachlorinated biphenyls showed an association between the concentrations in UC versus MS, and UC versus CS. These chemicals also showed high correlation coefficients between the chemical concentrations in UC of first babies and maternal age. These chemicals were closely related to each other when grouped on the basis of their concentrations using cluster analysis. In conclusion, we insist that UC is the best sample to assess fetal contamination status of persistent chemicals. There is a possibility that the assessment based on the contamination levels in CS result in an underestimation

    Random Iteration Algorithm for Graph-Directed Sets

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    A random iteration algorithm for graph-directed sets is defined and discussed. Similarly to the Barnsley-Elton\u27s theorem, it is shown that almost all sequences obtained by this algorithm reflect a probability measure which is invariant with respect to the system of contractions with probabilities

    Death Rate of Survivors in Nagasaki at Early Time of A-Bomb Explosion

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    The death rate of survivors at early time after A-bomb explosion was analyzed with the A-bomb disaster survey in Nagasaki city. Survivors who were alive September 1st, 1945 was 20,746 persons, in which 17,869 persons (86.1%) had information for the analysis. The death rate in 1945 of survivors exposed in their houses at less than 1,199 m from the hypocenter was higher than those exposed not in their houses. The death rate of survivors in 1946 decreased rapidly, although that of survivors exposed at less than 1,199 m from the hypocenter was still high

    Evaluation of antixenosis in soybean against <i>Spodoptera litura</i> by dual-choice assay aided by a statistical analysis model: Discovery of a novel antixenosis in Peking

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    The method for evaluating soybean (Glycine max) antixenosis against the common cutworm (Spodoptera litura) was developed based on a dual-choice assay aided by a statistical analysis model. This model was constructed from the results of a dual-choice assay in which Enrei, a soybean cultivar susceptible to S. litura, was used as both a standard and a test leaf disc for 2nd–5th instar larvae. The statistical criterion created by this model enabled the evaluation of the presence of antixenosis. This method was applied to four soybean varieties, including Tamahomare (susceptible), Himeshirazu (resistant), IAC100 (resistant), and Peking (unknown), as well as Enrei. Subsequently, the degrees of antixenosis were also compared by F-test, followed by maximum likelihood estimation (MLE). According to the results, the antixenosis of Tamahomare, Himeshirazu, and IAC100 was statistically reevaluated and Peking exhibited a novel antixenosis, which was stronger for 3rd–5th instar larvae than for 2nd instar
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