24,142 research outputs found
The Deep SWIRE Field III. WIYN Spectroscopy
We present the results of spectroscopy using HYDRA on the WIYN 3.5m telescope
of objects in the deep SWIRE radio field. The goal of the project was to
determine spectroscopic redshifts for as many of the brighter objects in the
field as possible, especially those detected in the radio and at 24 microns.
These redshifts are primarily being used in studies of galaxy evolution and the
connection of that evolution to AGN and star-formation. Redshifts measured for
365 individual objects are reported. The redshifts range from 0.03 to 2.5,
mostly with z < 0.9. The sources were selected to be within the WIYN HYDRA
field of approximately 30' in radius from the center of the SWIRE deep field,
10h46m00s, 59d 01'00" (J2000). Optical sources for spectroscopic observation
were selected from a r-band image of the field. A priority list of
spectroscopic targets was established in the following order: 20cm detections,
24 micron detections, galaxies with r < 20 and the balance made up of fainter
galaxies in the field. We provide a table listing the galaxy positions,
measured redshift and error, and note any emission lines that were visible in
the spectrum. In practice almost all the galaxies with r < 19 were observed
including all of the radio sources and most of the 24 microns sources with r <
20 and a sample of radio sources which had fainter optical counterparts on the
r-band image.Comment: 6 pages, 3 tables, 2 figures, full electronic tables at
http://www.aoc.nrao.edu/~fowen/papers/SWIRE/WIYNpaper3/, accepted ApJ Suppl
Serie
Forming collaborative parent-teacher relationships to increase parental involvement
This document reviews and summarizes the importance of parentteacher relationships and parental involvement in education. Both benefits and barriers will be discussed. Strategies and plans are provided as suggestions for teachers working with diverse populations. The importance of collaborative relationships and parental involvement are discussed for parents and teachers of children who are deaf or hard of hearing
Physiological Aspects of Genetics
A considerable amount of evidence indicates that desoxyribonucleic acid is capable of duplicating itself, a property also possessed by genes. (By a self-duplicating material, we mean one which plays some essential role in its own production.) Watson & Crick (1) have proposed a new structure for desoxyribonucleic acid which not only takes into account the existing analytical and x-ray diffraction data but also seems capable of explaining the mechanism of duplication. Their model consists of two helical chains coiled around the same axis, the purine and pyrimidine bases on the inside, the phosphate groups on the outside. The chains are held together by hydrogen bonds between the bases, the adenine residues of either chain being bonded specifically to thymine in the other, and similarly guanine to cytosine. The sequence of bases along one chain is not restricted, but once fixed the sequence along the other chain is determined. This complementarity, which is the most novel feature of the structure, suggests that duplication takes place by separation of the two chains, followed by the synthesis of its complement alongside each chain. The model is supported by recent x-ray diffraction studies (2, 3)
Current Star Formation in Post-Starburst Galaxies?
Radio continuum observations are a probe of star formation in galaxies, and
are unaffected by dust extinction. Observations of the distant rich cluster Cl
0939+4713 have detected radio galaxies classified as post-starburst (``k+a'')
on the basis of their optical spectra, and presumably this situation arises
from heavily dust-obscured star formation (Smail et al. 1999). We present the
results of a radio continuum survey of post-starburst galaxies identified from
the Las Campanas Redshift Survey by Zabludoff et al. (1996). This sample was
selected using very stringent criteria, and therefore provides an estimate on
the incidence of potential star formation in galaxies whose optical spectra
exhibit the strongest post-starburst features. We detected two of fifteen such
galaxies at radio luminosities consistent with moderate levels of star
formation. This result underscores the potential importance of dust extinction
when investigating star formation in galaxies.Comment: Replaced with corrected version of Table
A 20cm VLA Survey of Abell Clusters of Galaxies VI. Radio/Optical Luminosity Functions
From a statistically complete sample of 188 radio galaxies in Abell clusters,
we examine the radio/optical correlations, the FR I/II division, and the
univariate and bivariate luminosity functions. As suggested by Owen (1993), the
FR I/II division is shown to be a strong function of the optical luminosity of
the host galaxy (proportional to L_opt^2). This dependence is also seen in the
bivariate luminosity function, which suggests that the evolutionary tracks of
radio sources and/or the initial conditions in the source are governed by the
host galaxy properties. The probability for detecting radio emission increases
with optical luminosity. The optical dependence is clearly separated in the
integral luminosity functions which can be used as a constraint to models of FR
I radio power evolution. Additionally, the source counts from the integrated
univariate radio luminosity function (RLF) are consistent with our suggestion
in paper V that radio sources may be a transient phenomenon which occurs in all
elliptical galaxies at some time (or several times) over their lifetime. We
find no statistically significant differences in the luminosity functions
between rich cluster samples and radio sources not selected to reside in
clusters. These results suggest that all radio galaxies live in similar
environments in that the optical luminosity and the properties of the host
galaxy are the most important parameters which affect radio source formation
and evolution.Comment: 21 pages LaTeX, 3 tables, 12 figures. To appear in July 1996 A
Vesicular stomatitis virus glycoprotein is necessary for H-2-restricted lysis of infected cells by cytotoxic T lymphocytes
Vesicular stomatitis virus (VSV) elicited cytotoxic thymus-derived lymphocytes (CTLs) in mice of the BALB/c and three congenic strains (BALB.b, BALB.k, BALB.HTG). CTL lysis of VSV-infected fibroblasts from the four strains was restricted by the target cells' major histocompatibility complex (H-2). Target cells were also infected with two temperature-sensitive mutants of VSV, tsM and tsG in which, respectively, the viral matrix protein and glycoprotein are not expressed at 39 degrees (restrictive temperature) on the infected cell's surface membrane. At the restrictive temperature, cells infected with wild-type VSV or tsM were lysed by CTLs, but cells infected with tsG were not. The requirement for the glycoprotein on the target cell was also evident from the ability of antisera to the glycoprotein to block completely CTL lysis of VSV-infected cells
A study of the evolution of concentration in the pharmaceutical industry for the United Kingdom. Studies: Evolution of concentration and competition series
Quantum stress tensor for massive vector field in the space-time of a cylindrical black hole
The components of the renormalized quantum Energy-Momentum tensor for a
massive vector field coupled to the gravitational field configuration of a
static Black-String are analytically evaluated using the Schwinger-DeWitt
approximation. The general results are employed to investigate the pointwise
energy conditions for the quantized matter field, and it is shown that they are
violated at some regions of the spacetime, in particular the horizon of the
black hole.Comment: 4 pages, 3 figure
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