1,045 research outputs found

    System development of the Screwworm Eradication Data System (SEDS) algorithm

    Get PDF
    The use of remotely sensed data is reported in the eradication of the screwworm and in the study of the role of the weather in the activity and development of the screwworm fly. As a result, the Screwworm Eradication Data System (SEDS) algorithm was developed

    Evidence for Intrinsic Redshifts in Normal Spiral Galaxies

    Full text link
    The Tully-Fisher Relationship (TFR) is utilized to identify anomalous redshifts in normal spiral galaxies. Three redshift anomalies are identified in this analysis: (1) Several clusters of galaxies are examined in which late type spirals have significant excess redshifts relative to early type spirals in the same clusters, (2) Galaxies of morphology similar to ScI galaxies are found to have a systematic excess redshift relative to the redshifts expected if the Hubble Constant is 72 km s-1 Mpc-1, (3) individual galaxies, pairs, and groups are identified which strongly deviate from the predictions of a smooth Hubble flow. These redshift deviations are significantly larger than can be explained by peculiar motions and TFR errors. It is concluded that the redshift anomalies identified in this analysis are consistent with previous claims for large non-cosmological (intrinsic) redshifts.Comment: Accepted for publication at Astrophysics&Space Science. 36 pages including 8 tables and 7 figure

    Intrinsic Redshifts and the Tully-Fisher Distance Scale

    Full text link
    The Tully-Fisher relationship (TFR) has been shown to have a relatively small observed scatter of ~ +/-0.35 mag implying an intrinsic scatter < +/-0.30 mag. However, when the TFR is calibrated from distances derived from the Hubble relation for field galaxies scatter is consistently found to be +/-0.64 to +/-0.84 mag. This significantly larger scatter requires that intrinsic TFR scatter is actually much larger than +/-0.30 mag, that field galaxies have an intrinsic TFR scatter much larger than cluster spirals, or that field galaxies have a velocity dispersion relative to the Hubble flow in excess of 1000 km s-1. Each of these potential explanations faces difficulties contradicted by available data and the results of previous studies. An alternative explanation is that the measured redshifts of galaxies are composed of a cosmological redshift component predicted from the value of the Hubble Constant and a superimposed intrinsic redshift component previously identified in other studies. This intrinsic redshift component may exceed 5000 km s-1 in individual galaxies. In this alternative scenario a possible value for the Hubble Constant is 55-60 km s-1 Mpc-1.Comment: 15 pages, Astrophysics&Space Science - Accepted for publicatio

    Pollen amount and distribution in relation to seed set of male-sterile Triticum aestivum

    Get PDF
    LD2668 .T4 1967 A715Master of Scienc

    The Wolf effect and the Redshift of Quasars

    Full text link
    We consider a simple model, based on currently accepted models for active galactic nuclei, for a quasi-stellar object (QSO or ``quasar'') and examine the influence that correlation- induced spectral changes (``The Wolf Effect'') may have upon the redshifts of the optical emission lines.Comment: 13 pages, 3 figures. To be published in J. European Optical Soc. A: Pure and Applied Optic

    Configurational entropy of Wigner crystals

    Get PDF
    We present a theoretical study of classical Wigner crystals in two- and three-dimensional isotropic parabolic traps aiming at understanding and quantifying the configurational uncertainty due to the presence of multiple stable configurations. Strongly interacting systems of classical charged particles confined in traps are known to form regular structures. The number of distinct arrangements grows very rapidly with the number of particles, many of these arrangements have quite low occurrence probabilities and often the lowest-energy structure is not the most probable one. We perform numerical simulations on systems containing up to 100 particles interacting through Coulomb and Yukawa forces, and show that the total number of metastable configurations is not a well defined and representative quantity. Instead, we propose to rely on the configurational entropy as a robust and objective measure of uncertainty. The configurational entropy can be understood as the logarithm of the effective number of states; it is insensitive to the presence of overlooked low-probability states and can be reliably determined even within a limited time of a simulation or an experiment.Comment: 12 pages, 8 figures. This is an author-created, un-copyedited version of an article accepted for publication in J. Phys.: Condens. Matter. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The definitive publisher-authenticated version is available online at 10.1088/0953-8984/23/7/075302.

    The Distribution of Redshifts in New Samples of Quasi-stellar Objects

    Get PDF
    Two new samples of QSOs have been constructed from recent surveys to test the hypothesis that the redshift distribution of bright QSOs is periodic in log(1+z)\log(1+z). The first of these comprises 57 different redshifts among all known close pairs or multiple QSOs, with image separations \leq 10\arcsec, and the second consists of 39 QSOs selected through their X-ray emission and their proximity to bright comparatively nearby active galaxies. The redshift distributions of the samples are found to exhibit distinct peaks with a periodic separation of 0.089\sim 0.089 in log(1+z)\log(1+z) identical to that claimed in earlier samples but now extended out to higher redshift peaks z=2.63,3.45z = 2.63, 3.45 and 4.47, predicted by the formula but never seen before. The periodicity is also seen in a third sample, the 78 QSOs of the 3C and 3CR catalogues. It is present in these three datasets at an overall significance level 10510^{-5} - 10610^{-6}, and appears not to be explicable by spectroscopic or similar selection effects. Possible interpretations are briefly discussed.Comment: submitted for publication in the Astronomical Journal, 15 figure

    Globular Clusters as Candidates for Gravitational Lenses to Explain Quasar-Galaxy Associations

    Full text link
    We argue that globular clusters (GCs) are good candidates for gravitational lenses in explaining quasar-galaxy associations. The catalog of associations (Bukhmastova 2001) compiled from the LEDA catalog of galaxies (Paturel 1997) and from the catalog of quasars (Veron-Cetty and Veron 1998) is used. Based on the new catalog containing 8382 pairs, we show that one might expect an increased number of GCs around irregular galaxies of types 9 and 10 from the hypothesis that distant compact sources are gravitationally lensed by GCs in the halos of foreground galaxies. The King model is used to determine the central surface densities of 135 GCs in the Milky Way. The distribution of GCs in central surface density was found to be lognormal.Comment: 22 pages, 4 figure
    corecore