The Dynamics and Light Curves of Beamed Gamma Ray Burst Afterglows

The energy requirements of gamma ray bursts have in past been poorly constrained because of three major uncertainties: The distances to bursts, the degree of burst beaming, and the efficiency of gamma ray production. The first of these has been resolved, with both indirect evidence (the distribution of bursts in flux and position) and direct evidence (redshifted absorption features in the afterglow spectrum of GRB 970508) pointing to cosmological distances. We now wish to address the second uncertainty. Afterglows allow a statistical test of beaming, described in an earlier paper. In this paper, we modify a standard fireball afterglow model to explore the effects of beaming on burst remnant dynamics and afterglow emission. If the burst ejecta are beamed into angle zeta, the burst remnant's evolution changes qualitatively once its bulk Lorentz factor Gamma < 1/zeta: Before this, Gamma declines as a power law of radius, while afterwards, it declines exponentially. This change results in a broken power law light curve whose late-time decay is faster than expected for a purely spherical geometry. These predictions disagree with afterglow observations of GRB 970508. We explored several variations on our model, but none seems able to change this result. We therefore suggest that this burst is unlikely to have been highly beamed, and that its energy requirements were near those of isotropic models. More recent afterglows may offer the first practical applications for our beamed models.Comment: 18 pages, uses emulateapj.sty, four embedded postscript figures. Submitted to The Astrophysical Journal, 199

Advanced turbine engine mainshaft lubrication system investigation. Part 2 - Detailed face seals performance, mass spectroscopic study of a test fluid, and supplementary test data Final report

Face seal performance, mass spectroscopic test fluid study and supplementary test data for supersonic turbine engine mainshaft lubrication syste

In the Service of Citizenship: A Study of Student Involvement in Community Service

I learn more through my volunteer work than I ever do in any of my classes at school. Talking to people from diverse backgrounds provides so much insight that people just can\u27t imagine. I study all these different theories in political science and sociology, but until you get a chance to see how the social world influences people\u27s everyday lives, it just doesn\u27t have that much meaning. I have been involved in volunteer work ever since I was in high school, and I\u27ll probably continue to do stuff like Habitat [for Humanity] until I\u27m old and gray. I get a lot out of working to serve others, and it\u27s a good feeling to know that I have helped someone even if it\u27s in some small way. It helps me to cherish people more and understand what life is all about

Microbiological methods for the water recovery systems test, revision 1.1

Current microbiological parameters specified to verify microbiological quality of Space Station Freedom water quality include the enumeration of total bacteria, anaerobes, aerobes, yeasts and molds, enteric bacteria, gram positives, gram negatives, and E. coli. In addition, other parameters have been identified as necessary to support the Water Recovery Test activities to be conducted at the NASA/MSFC later this year. These other parameters include aerotolerant eutrophic mesophiles, legionellae, and an additional method for heterotrophic bacteria. If inter-laboratory data are to be compared to evaluate quality, analytical methods must be eliminated as a variable. Therefore, each participating laboratory must utilize the same analytical methods and procedures. Without this standardization, data can be neither compared nor validated between laboratories. Multiple laboratory participation represents a conservative approach to insure quality and completeness of data. Invariably, sample loss will occur in transport and analyses. Natural variance is a reality on any test of this magnitude and is further enhanced because biological entities, capable of growth and death, are specific parameters of interest. The large variation due to the participation of human test subjects has been noted with previous testing. The resultant data might be dismissed as 'out of control' unless intra-laboratory control is included as part of the method or if participating laboratories are not available for verification. The purpose of this document is to provide standardized laboratory procedures for the enumeration of certain microorganisms in water and wastewater specific to the water recovery systems test. The document consists of ten separate cultural methods and one direct count procedure. It is not intended nor is it implied to be a complete microbiological methods manual

The Teaching Consultants\u27 Workshop

This paper describes the Teaching Consultants\u27 Workshop offered in the Teaching Consultation Program in the University of Kentucky Community College System. Faculty members from different campuses, who have been recognized by their colleagues as outstanding teachers and who have attended a training workshop, serve as consultants. The consultants attend the workshop after completing the information collection phase in work with individual clients. Consultants present their clients to each other through collected data and videotape, and discuss alternative teaching strategies that might be used in each case

The Dynamic Tensions of Service Learning in Higher Education: A Philosophical Perspective

Senior faculty in a peace and justice program at a small liberal arts college reject the efforts of a student affairs professional to help the faculty connect their teaching to practice through service activities in the local community. One faculty member openly wonders how out-of-class activities such as community service have anything to do with interdisciplinary theories of social justice. A director of an office of community service is upset because the provost has decided to develop a Center for Community Service Learning. The director sees this as an attempt to usurp the good work of student affairs and feels that attempts to engage faculty will be difficult, if not futile. A department chair in an American Thought and Language program at a large research university asks an associate professor being considered for promotion to full professor to explain in writing to the promotion and tenure committee the relevance of his research on service learning. Both the chair and the committee are apprehensive about service learning as a legitimate area of scholarly inquiry. And finally, a local social service agency in a university town has had its till of student volunteers after repeatedly receiving complaints from clients about patronizing attitudes expressed by the students

Young red supergiants and the near infrared light appearance of disk galaxies

Disk galaxies often show prominent nonaxisymmetric features at near-infrared wavelengths. Such features may indicate variations in the surface density of stellar mass, contributions from young red supergiants in star forming regions, or substantial dust obscuration. To distinguish among these possibilities, we have searched for spatial variations in the 2.3 micron photometric CO index within the disks of three nearby galaxies (NGC 278, NGC 2649, & NGC 5713). This index measures the strength of the absorption bands of molecular CO in stellar atmospheres, and is strong in cool, low surface-gravity stars, reaching the largest values for red supergiants. We observe significant spatial CO index variations in two galaxies (NGC 278 & NGC 5713), indicating that the dominant stellar population in the near-infrared is not everywhere the same. Central CO index peaks are present in two galaxies; these could be due to either metallicity gradients or recent star formation activity. In addition, significant azimuthal CO index variations are seen in NGC 278. Because strong azimuthal metallicity gradients are physically implausible in disk galaxies, these features are most naturally explained by the presence of a young stellar population. The fraction of 2 micron light due to young stellar populations in star forming regions can be calculated from our data. Overall, young stellar populations can contribute ~3% of a (normal) galaxy's near infrared flux. Locally, this fraction may rise to ~33%. Thus, young stars do not dominate the total near infrared flux, but can be locally dominant in star forming regions, and can bias estimates of spiral arm amplitude or other nonaxisymmetric structures in galaxies' mass distributions.Comment: 28 pages including 3 postscript figures. A fourth figure is in jpeg format. Uses AASTeX. Accepted for publication in The Astronomical Journa

The Teaching Consultants\u27 Workshop

This paper describes the Teaching Consultants\u27 Workshop offered in the Teaching Consultation Program in the University of Kentucky Community College System. Faculty members from different campuses, who have been recognized by their colleagues as outstanding teachers and who have attended a training workshop, serve as consultants. The consultants attend the workshop after completing the information collection phase in work with individual clients. Consultants present their clients to each other through collected data and videotape, and discuss alternative teaching strategies that might be used in each case

Natural Resource Inventory and Management Recommendations Whites Mill Property Salford Township, Montgomery County

The Whites Mill Tract, approximately 100 acres in size, was purchased by Salford Township in 1998 as open space. It is located in a forested landscape comprising about 10,000 acres that stretches across upper Montgomery and Bucks Counties. Because of the extensive contiguous forested area, this region is the target of several efforts to protect the natural resources and its ecological integrity (see Figure 1). The Natural Lands Trust (NLT) and the Montgomery County Conservancy have collaborated to secure conservation easements on the 1700 acre Musser Scout Reservation in the Unami Creek Valley. NLT is also working with Milford Township, Bucks County to extend protection efforts upstream along the Unami and Ridge Valley Creeks. Marlborough Township, Montgomery County recently purchased the Camp Skymount property, which is located about three-quarters mile upstream from Whites Mill pond. NLT\u27s Fulshaw-Craeg Preserve is located approximately one mile downstream. In addition NLT holds conservation easements on a number of private properties in the area