94,886 research outputs found
STRIGOL - A string oriented language
Reference manual on Strigol program for data strings and string manipulation language
A Color-Magnitude Diagram for a Globular Cluster In the Giant Elliptical Galaxy NGC 5128
The Hubble Space Telescope has been used to obtain WFPC2 (V,I) photometry for
a large sample of stars in the outer halo of the giant elliptical NGC 5128 (d =
4 Mpc). The globular cluster N5128-C44, at the center of the Planetary Camera
field, is well enough resolved to permit the construction of a color-magnitude
diagram (CMD) for it which covers the brightest two magnitudes of the giant
branch. The CMD is consistent with that of a normal old, moderately
low-metallicity ([Fe/H] = -1.30 globular cluster, distinctly more metal-poor
than most of the field halo stars at the same projected location (which average
[Fe/H] ~ -0.5). This is the most distant globular cluster in which direct
color-magnitude photometry has been achieved to date, and the first one
belonging to a giant E galaxy.Comment: 12 pages, LaTeX, including 5 postscript figures; submitted to
Astronomical Journa
Fishes of the Mountain Province Section of the Ouachita River
A survey of the fishes of the mountain province section of the Ouachita River from the headwaters to Remmel Dam using field collections, literature records, and museum collections showed the ichthyofauna to be made up of 80 species representing 16 families. Fourteen species not previously reported from the mountain province section of the river were collected in this survey. These species include Ichthyomyzon gagei, Nocomis asper, Notropis ortenburgeri, N. rubellus, Pimephales promelas, Moxostoma carinatum, Noturus taylori, Fundulus notatus, Lepomis humilis, Etheostoma histrio, E. proeliare, Percina maculata, P. nasuta, and P. uranidea. The Nocomis specimens were the first collected from the Ouachita River system and the discovery of Noturus taylori represents a major range extension
Detecting binocular 3-D motion in static 3-D noise: No effect of viewing distance.
Relative binocular disparity cannot tell us the absolute 3-D shape of an object, nor its 3-D trajectory if it is moving, unless the visual system has independent access to how far away the object is at any moment. Indeed, as the viewing distance is changed, the same disparate retinal motions will correspond to very different real 3-D trajectories. In this paper we were interested in whether binocular 3-D motion detection is affected by viewing distance. We used a visual search task in which the observer is asked to detect a target dot, moving in 3-D, amidst 3-D stationary distractor dots. We found that distance does not affect detection performance. Motion-in-depth is consistently harder to detect than the equivalent lateral motion, for all viewing distances. For a constant retinal motion with both lateral and motion-in-depth components, detection performance is constant despite variations in viewing distance that produce large changes in the direction of the 3-D trajectory. We conclude that binocular 3-D motion detection relies on retinal, not absolute visual signals
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