O. T. Johnson

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The "thinning" operation on a discrete random variable is the natural discrete analog of scaling a continuous variable, i.e., multiplying it by a constant. We examine the role and properties of thinning in the context of information-theoretic inequalities for Poisson approximation. The classical Binomial-to-Poisson convergence, often referred to as the "law(More)
Cell behavior is three-dimensional (3-D), even when it takes place on a flat surface. Migrating cells form pseudopods on and off the substratum, and the cell body undergoes height changes associated with a 1 min behavior cycle. Inside the cell, the nucleus has a 3-D migratory cycle, and vesicles move up and down in the z-axis as a cell locomotes. For these(More)
Fisher information plays a fundamental role in the analysis of Gaussian noise channels and in the study of Gaussian approximations in probability and statistics. For discrete random variables, the scaled Fisher information plays an analogous role in the context of Poisson approximation. Our first results show that it also admits a minimum mean squared error(More)
BACKGROUND High cholesterol is identified as a major risk factor for chronic non-communicable diseases, especially cardiovascular and cerebrovascular diseases. Monitoring trends of cholesterol levels and comparing trends across population groups are important to assess population distribution and risks related to cholesterol change over time. Cholesterol(More)
Subjects balanced a dowel rod on the right or left index finger while speaking, while remaining silent, and while humming a melody. In males balancing times for the right hand decreased with concurrent verbalization. Verbalization had no effect on left hand performance in males, nor on either hand in females. Concurrent humming had no effect on performance(More)
Elevated total plasma homocysteine (tHcy) in humans is associated with cardiovascular disease but prevention trials have failed to confirm causality. Reported reasons for this association have been that homocysteine and its major genetic determinant methylenetetrahydrofolate reductase (MTHFR) may have an effect on HDL and Apolipoprotein (Apo) A1 levels. We(More)
We present the first X-ray spectrum obtained by the Low Energy Transmission Grating Spectrometer (LETGS) aboard the Chandra X-ray Observatory. The spectrum is of Capella and covers a wavelength range of 5–175Å (2.5–0.07 keV). The measured wavelength resolution, which is in good agreement with ground calibration, is ∆λ ≃ 0.06Å (FWHM). Although in-flight(More)