1,045 research outputs found
System development of the Screwworm Eradication Data System (SEDS) algorithm
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
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
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
LD2668 .T4 1967 A715Master of Scienc
The Wolf effect and the Redshift of Quasars
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
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
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
. The first of these comprises 57 different redshifts among all
known close pairs or multiple QSOs, with image separations 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 in identical to that claimed
in earlier samples but now extended out to higher redshift peaks 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 -
, 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
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
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