Physical Sciences and Mathematics Commons^™

Trace Fossils Of Shallow Subtidal To Dunal Ichnofacies In Bahamian Quaternary Carbonates, H. Allen Curran, Brian White

Geosciences: Faculty Publications

Pleistocene and Holocene carbonate grainstones or calcarenites capping the islands of the Bahamas commonly contain distinctive animal and/or plant trace fossils. Three ichnocoenoses within the Skolithos and Psilonichnus ichnofacies are recognized in the transition from sediments deposited in the shallow shelf environment, commonly associated with coral reefs, to sediments of the coastal dune environment. Analog relationships between the trace fossils and modern tracemakers can be established in many cases, and this correspondence strengthens the interpretive model. Ophiomorpha

and Skolithos linearis characterize beds deposited in shallow shelf settings. Psilonich- nus upsilon, the fossil burrow of the ghost crab Ocypode quadrata …

Discovery Of A Lyα Galaxy Near A Damped Lyα Absorber At Z = 2.3, James D. Lowenthal, Craig J. Hogan, Richard F. Green, Adeline Caulet, Bruce E. Woodgate, Larry Brown, Craig B. Foltz

Astronomy: Faculty Publications

We report the detection of a galaxy associated with the damped Lyα absorbing cloud seen at z = 2.309 toward the QSO PHL 957 (zem = 2.681). The galaxy was discovered in deep Fabry-Perot narrow-band CCD frames and was subsequently imaged spectroscopically. In addition to a strong but narrow Lyα emission line (FLyα = 5.6 × 10-16 ergs s-1 cm-2, FWHM ∼ 700 km s-1) and weaker C IV and He II lines, the object shows continuum at V ∼ 24, with a slope (in Fν) rising slightly toward the red, similar to what is seen in high-redshift radio galaxies; …

Study Of The Effect Of Relativistic Time Dilation On Cosmic Ray Muon Flux - Undergraduate Modern Physics Experiment, Nalini Easwar, Douglas A. Macintire

Physics: Faculty Publications

An experiment to study the effect of relativistic time dilation on secondary muon fluxes observed at different altitudes is described in this article. Muons, produced as secondary particles from the interaction of primary cosmic rays with the upper atmosphere, form a natural and abundant source of subatomic ``clocks'' moving at very high speeds. The measured muon flux on a mountain relative to that measured at sea level can be compared to predictions from calculations that take into account the relativistic time dilation in the muon frame. Situations under which such an experiment can be successfully performed are explored with a …

Emission From The Z = 2 Damped Lyα Absorber Toward Q1215 + 333, Richard Elston, Jill Bechtold, James Lowenthal, Marcia Rieke

Astronomy: Faculty Publications

We have detected narrow emission lines at 1.118 μm and 1.456 μm in the spectrum of the z = 2.606 quasar Q1215 + 333, corresponding to [O II] λ3727 and Hβ at z = 1.9984, the redshift of a damped Lyα absorber toward this quasar. The intensity of the Hβ line is 7.6 ± 2 × 10-16 ergs cm-2 s-1, which corresponds to a line luminosity of 5 × 1042 ergs s-1 h-2100 (q0 = 0.5). If we assume that the photoionization producing the emission is due purely to massive star formation with a Salpeter initial mass function, we find …

Systematic Variation Of Transport And Thermodynamic Properties With Degree Of Reduction In Nd1.85ce0.15cuo4-, Nathanael A. Fortune, K. Murata, M. Ishibashi, Y. Yokoyama, Y. Nishihara

Physics: Faculty Publications

Superconductivity only occurs in Nd1.85Ce0.15CuO4- after heat treatment in a reducing at- mosphere; yet we find the oxygen loss during reduction to be remarkably small. To better understand the physical role of reduction, we have systematically varied the degree of reduction in a series of ceramic samples by varying the partial pressures of oxygen and argon in the reducing atmosphere, keeping the total pressure constant. We find that small increases in the degree of reduction strongly increase the apparent carrier density and the superconducting Meissner fraction. We also find that there is an optimal degree of reduction to produce a …

The Stratigraphy And Ichnology Of A Submarine Cave In The Exuma Cays, Bahamas, H. Allen Curran, Robert F. Dill

Geosciences: Faculty Publications

Reprinted from: Roger J. Bain (ed.), 1991, Proceedings of the Fifth Symposium on the Geology of the Bahamas: San Salvador, Bahamian Field Station.