Biomedical subjects

J F Nicoll

Publications and source records attributed to J F Nicoll.

6 recordsLinked to original sources

PubMed1998

Cosmological implications of a large complete quasar sample.

Objective and reproducible determinations of the probabilistic significance levels of the deviations between theoretical cosmological prediction and direct model-independent observation are made for the Large Bright Quasar Sample [Foltz, C., Chaffee, F. H., Hewett, P. C., MacAlpine, G. M., Turnshek, D. A., et al. (1987) Astron. J. 94, 1423-1460]. The Expanding Universe model as represented by the Friedman-Lemaitre cosmology with parameters qo = 0, Lambda = 0 denoted as C1 and chronometric cosmology (no relevant adjustable parameters) denoted as C2 are the cosmologies considered. The mean and the dispersion of the apparent magnitudes and the slope of the apparent magnitude-redshift relation are the directly observed statistics predicted. The C1 predictions of these cosmology-independent quantities are deviant by as much as 11sigma from direct observation; none of the C2 predictions deviate by >2sigma. The C1 deviations may be reconciled with theory by the hypothesis of quasar "evolution," which, however, appears incapable of being substantiated through direct observation. The excellent quantitative agreement of the C1 deviations with those predicted by C2 without adjustable parameters for the results of analysis predicated on C1 indicates that the evolution hypothesis may well be a theoretical artifact.

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PubMed1992

Apparent nonlinearity of the redshift-distance relation in infrared astronomical satellite galaxy samples.

The Hubble (linear) redshift-distance law predicts values for directly observed quantities that are quite deviant from their actual values in infrared astronomical satellite (IRAS) galaxy samples. These samples are objectively defined, have modern measurements, are presently the largest such samples to which the Hubble law is theoretically applicable, and are otherwise generally considered to be statistically appropriate. The Hubble law predicts in particular that the dispersion in log flux will be much greater than it is observed to be. This type of deviation is fundamentally incapable of explanation via the assumption of any physically known type of perturbation. The Lundmark (quadratic) redshift-distance law predicts values for these directly observed quantities that are consistent with, and in fact quite close to, their actual values in the same samples. The predictions of a cubic law are typically deviant from observation but somewhat less so than those of the Hubble law. The Lundmark law accurately predicts the deviations from observation of statistical estimates predicated on either the Hubble or the cubic law. Parallel predictions for the latter laws for the results of statistical estimation predicated on the alternative laws are typically quite inaccurate. The Hubble and Lundmark laws are predicted at the low redshifts of the IRAS galaxy samples by generic big bang cosmology (BBC) and chronometric cosmology (CC), respectively. The present results confirm earlier studies of a variety of objectively defined samples of discrete sources in other wave bands that were contraindicative of BBC and indicative of CC.

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PubMed1982

Spatial homogeneity and redshift-distance laws.

Spatial homogeneity in the radial direction of low-redshift galaxies is subjected to Kafka-Schmidt V/V(m) tests using well-documented samples. Homogeneity is consistent with the assumption of the Lundmark (quadratic redshift-distance) law, but large deviations from homogeneity are implied by the assumption of the Hubble (linear redshift-distance) law. These deviations are similar to what would be expected on the basis of the Lundmark law. Luminosity functions are obtained for each law by a nonparametric statistically optimal method that removes the observational cutoff bias in complete samples. Although the Hubble law correlation of absolute magnitude with redshift is reduced considerably by elimination of the bias, computer simulations show that its bias-free value is nevertheless at a satistically quite significant level, indicating the self-inconsistency of the law. The corresponding Lundmark law correlations are quite satisfactory satistically. The regression of redshift on magnitude also involves radial spatial homogeneity and, according to R. Soneira, has slope determining the redshift-magnitude exponent independently of the luminosity function. We have, however, rigorously proved the material dependence of the regression on this function and here exemplify our treatment by using the bias-free functions indicated, with results consistent with the foregoing argument.

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PubMed1980

Statistical invalidation of the Hubble law.

An optimal nonparametric technique for elimination of the observation cutoff bias, on the assumption of a given theoretical cosmology, is applied to the redshift-magnitude and redshift-angular diameter relationships in objectively specified large galaxy samples. The estimates obtained on the assumptions of linear and square redshift-distance laws are uniformly and strongly favorable to the square law. The question of whether the relative inferiority of the linear law can scientifically be ascribed to ancillary extragalactic phenomena is addressed by nonparametric crosstesting of the alternative hypotheses. Each law is used to predict the results of a statistical analysis based on the alternative law by using the given data and computer simulations. The result is that the square law predicts with statistical exactitude the results of the analyses of the linear law; but the linear law predicts with near certainty that the fit of the square law will be much worse than is observed. In the absence of independent validation of a variety of ancillary hypotheses that have been adduced in connection with the linear law, it seems necessary to conclude that the Hubble law lacks an objective statistical foundation.

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PubMed1978

Observational validation of the chronometric cosmology: The redshift-magnitude relation for quasi-stellar objects.

A statistical study is made of the redshift-magnitude relation for a recent comprehensive catalogue of quasi-stellar objects. The chronometric theory, although devoid of free parameters such as the q(0) and Lambda of the expansion theory, provides an excellent fit to the observed relation. The expansion theory does not provide an empirically meaningful fit.

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PubMed1975

Phenomenological analysis of observed relations for low-redshift galaxies.

Maximum-likelihood estimates are made for the exponent p in the phenomenological redshift-distance relation z [unk] r(p) for galaxies at redshifts less, similar0.03, on the basis of redshift (z)-magnitude (m)-apparent diameter (theta) observations given in the Reference Catalogue of Bright Galaxies [de Vaucouleurs, G. & de Vaucouleurs, A. (1964)]. The estimates are in the range 1.96 </= p </= 2.04 for the full sample of 742 galaxies having m - z - theta data, with dispersions less, similar0.08, and in a similar but broader range for various subsamples. Explicit allowance for an observational cut-off in apparent magnitude in the m - z relation reinforces the result that p approximately 2. Independent estimation based on a cut-off independent generalized Kafka-Schmidt V/V(m) test for a subsample in conservatively limited redshift and magnitude ranges, yields p = 2.05.

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