4,872 research outputs found

    Variation in actual relationship among descendants of inbred individuals

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    In previous analyses, the variation in actual, or realized, relationship has been derived as a function of map length of chromosomes and type of relationship, the variation being greater the shorter the total chromosome length and the coefficient of variation being greater the more distant the relationship. Here, the results are extended to allow for the relatives' ancestor being inbred. Inbreeding of a parent reduces variation in actual relationship among its offspring, by an amount that depends on the inbreeding level and the type of mating that led to that level. For descendants of full-sibs, the variation is reduced in later generations, but for descendants of half-sibs, it is increased

    Empirical source noise prediction method with application to subsonic coaxial jet mixing noise

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    A general empirical method, developed for source noise predictions, uses tensor splines to represent the dependence of the acoustic field on frequency and direction and Taylor's series to represent the dependence on source state parameters. The method is applied to prediction of mixing noise from subsonic circular and coaxial jets. A noise data base of 1/3-octave-band sound pressure levels (SPL's) from 540 tests was gathered from three countries: United States, United Kingdom, and France. The SPL's depend on seven variables: frequency, polar direction angle, and five source state parameters: inner and outer nozzle pressure ratios, inner and outer stream total temperatures, and nozzle area ratio. A least-squares seven-dimensional curve fit defines a table of constants which is used for the prediction method. The resulting prediction has a mean error of 0 dB and a standard deviation of 1.2 dB. The prediction method is used to search for a coaxial jet which has the greatest coaxial noise benefit as compared with an equivalent single jet. It is found that benefits of about 6 dB are possible

    Tabulation and summary of thermodynamic effects data for developed cavitation on ogive-nosed bodies

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    Thermodynamic effects data for developed cavitation on zero and quarter caliber ogives in Freon 113 and water are tabulated and summarized. These data include temperature depression (delta T), flow coefficient (C sub Q), and various geometrical characteristics of the cavity. For the delta T tests, the free-stream temperature varied from 35 C to 95 C in Freon 113 and from 60 C to 125 C in water for a velocity range of 19.5 m/sec to 36.6 m/sec. Two correlations of the delta T data by the entrainment method are presented. These correlations involve different combinations of the Nusselt, Reynolds, Froude, Weber, and Peclet numbers and dimensionless cavity length

    Correlations by the entrainment theory of thermodynamic effects for developed cavitation in venturis and comparisons with ogive data

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    A semi-empirical entrainment theory was employed to correlate the measured temperature depression, Delta T, in a developed cavity for a venturi. This theory correlates Delta t in terms of the dimensionless numbers of Nusselt, Reynolds, Froude, Weber and Peclet, and dimensionless cavity length, L/D. These correlations are then compared with similar correlations for zero and quarter caliber ogives. In addition, cavitation number data for both limited and developed cavitation in venturis are presented

    Fractal Characterizations of MAX Statistical Distribution in Genetic Association Studies

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    Two non-integer parameters are defined for MAX statistics, which are maxima of dd simpler test statistics. The first parameter, dMAXd_{MAX}, is the fractional number of tests, representing the equivalent numbers of independent tests in MAX. If the dd tests are dependent, dMAX<dd_{MAX} < d. The second parameter is the fractional degrees of freedom kk of the chi-square distribution χk2\chi^2_k that fits the MAX null distribution. These two parameters, dMAXd_{MAX} and kk, can be independently defined, and kk can be non-integer even if dMAXd_{MAX} is an integer. We illustrate these two parameters using the example of MAX2 and MAX3 statistics in genetic case-control studies. We speculate that kk is related to the amount of ambiguity of the model inferred by the test. In the case-control genetic association, tests with low kk (e.g. k=1k=1) are able to provide definitive information about the disease model, as versus tests with high kk (e.g. k=2k=2) that are completely uncertain about the disease model. Similar to Heisenberg's uncertain principle, the ability to infer disease model and the ability to detect significant association may not be simultaneously optimized, and kk seems to measure the level of their balance

    Spectroscopy of quasar candidates from the case low-dispersion survey

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    Case Low-Dispersion Northern Sky Survey. Thirteen of them are quasars, ranging in redshift from 0.0786 to 2.67, with a median redshift of 2. CSO 203 is a broad absorption-line quasar, and CSO 38 may have substantial associated absorption in the cores of emission lines. Several other objects show some intervening absorption, and all of them are bright enough to make the follow-up studies practical. CSO 251 is a bright (~15m), previously uncataloged quasar. The remaining objects are Galactic stars, five subdwarfs, and one hot white dwarf (CSO 160)

    A response to “Likelihood ratio as weight of evidence: a closer look” by Lund and Iyer

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    Recently, Lund and Iyer (L&amp;I) raised an argument regarding the use of likelihood ratios in court. In our view, their argument is based on a lack of understanding of the paradigm. L&amp;I argue that the decision maker should not accept the expert’s likelihood ratio without further consideration. This is agreed by all parties. In normal practice, there is often considerable and proper exploration in court of the basis for any probabilistic statement. We conclude that L&amp;I argue against a practice that does not exist and which no one advocates. Further we conclude that the most informative summary of evidential weight is the likelihood ratio. We state that this is the summary that should be presented to a court in every scientific assessment of evidential weight with supporting information about how it was constructed and on what it was based

    The cosmic submillimeter background - A signature of the initial burst of galaxy formation?

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    We propose a heuristic model for the origin of the cosmic submillimeter background (SMB), reported by the Nagoya-Berkeley collaboration. The SMB is interpreted as a direct signature of an epoch of (initial) galaxy formation at z_(gf) ~ 10 - 15. The sources of the SMB are proposed to be dust-shrouded starburst protogalaxies, similar to the luminous IRAS galaxies at low redshifts. We interpret them as the progenitors of old stellar populations at low redshifts, ellipticals, bulges, and stellar components of the halos. The largest allowed time scales for the star formation in these models are in the range FWHM ~ 0.2 - 0.6 Gyr, for Ω _0 = 0.1; for Ω _0 = 1, the allowed widths are about a factor of two lower. In order not to overproduce the baryonic mass density, it is necessary that the IMF in these starbursts is biased towards high-mass stars; however, a substantial range in the IMF parameters is allowed. This postulated population of protogalaxies may be an important contributor to the diffuse soft x-ray background. The predicted surface density of protogalaxies would be in the range ~10-100 arcsec^(-2), which is consistent with all relevant anisotropy measurements available at this time
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