Discovery of the most isolated globular cluster in the local universe

We report the discovery of two new globular clusters in the remote halos of M81 and M82 in the M81 Group based on Hubble Space Telescope archive images. They are brighter than typical globular clusters (MV = -9.34 mag for GC-1 and M_V = -10.51 mag for GC-2), and much larger than known globular clusters with similar luminosity in the MilkyWay Galaxy and M81. Radial surface brightness profiles for GC-1 and GC-2 do not show any features of tidal truncation in the outer part. They are located much farther from both M81 and M82 in the sky, compared with previously known star clusters in these galaxies. Color-magnitude diagrams of resolved stars in each cluster show a well-defined red giant branch (RGB), indicating that they are metal-poor and old. We derive a low metallicity with [Fe/H] $\simeq -2.3$ and an old age ~14 Gyr for GC-2 from the analysis of the absorption lines in its spectrum in the Sloan Digital Sky Survey in comparison with the simple stellar population models. The I-band magnitude of the tip of the RGB for GC-2 is 0.26 mag fainter than that for the halo stars in the same field, showing that GC-2 is ~400 kpc behind the M81 halo along our line of sight. The deprojected distance to GC-2 from M81 is much larger than any other known globular clusters in the local universe. This shows that GC-2 is the most isolated globular cluster in the local universe.Comment: 6 pages with 5 figure

Acoustical Analysis of a Desktop Personal Computer System

This thesis investigates acoustical and psychoacoustical emissions of a desktop computer system by attempting to understand, measure, and attenuate computer noise. Five cooling fans were examined: the CPU fan, the GPU fan, the PSU fan, a rear case fan, and a front case fan. The fans were tested individually, outside of the computer then installed within. The fully operating computer was also tested. Attenuation techniques tested were: installing acoustic insulation, software modification, and hardware modification. After experimentation was performed, the following was determined: acoustic insulation did not appear to be a viable noise reduction technique; CPU fan software modification for the purpose of noise reduction is not effective but does reduce power use; and hardware modification was not a useful technique when the case fans were installed in the fully operating computer because they were overpowered by the other noise sources present

Task Interrupted By A Poisson Process

We consider a task which has a completion time T (if not interrupted), which is a random variable with probability density function (pdf) f(t), t\u3e0. Before it is complete, the task may be interrupted by a Poisson process with rate lambda. If that happens, then the task must begin again, with the same completion time random variable T, but with a potentially different realization. These interruptions can reoccur, until eventually the task is finished, with a total time of W. In this paper, we will find the Laplace Transform of W in several special cases

Exploring Cognitive Maps through Sketching

Abstract Periodic testing has been found to improve the accuracy of participants’ cognitive maps when an onscreen map is provided, however, it is unclear whether the same results would occur without the onscreen map. The current study investigated whether drawing a map periodically while exploring the virtual environment Silcton would improve cognitive map accuracy. Participants explored Silcton and were stopped every 4 minutes to either sketch a map of Silcton, identify items seen in Silcton, or colour an unrelated picture, and a baseline group was not stopped. All groups drew a final sketch map and completed a direction estimation task. Results indicated that periodic testing using sketching led to significantly more accurate final sketch maps when compared to periodic testing using identified items but did not result in more accurate sketches across other groups or improved direction estimation scores. Accurate and inaccurate mappers demonstrated improved, but differing, accuracy across sketch development

Images of American women in war: Protector or protected?

This study analyzes the prevalent historic and contemporary images of American women in war. Evidence suggests that while men have been endowed with the responsibilities of the protector, women have been more comfortably considered as society\u27s protected. Chapter One provides a review of the relevant literature. It assesses the construction, endurance and implications of gender images, as well as the protector-protected relationship, in the American Military. Chapters Two and Three analyze the images of women over the history of American conflicts. It reveals that the images and roles of women as protected are subject to a process of expansion and contraction. In Chapter Four, this framework is applied to the 1991 Persian Gulf War. Despite an expanded military role, women both on the homefront, and on the battle front, were portrayed by the media as the protected. This finding was reinforced by the case study of Gulf War POW, Melissa Rathbun-Nealy, which includes a content analysis and personal interview. The Persian Gulf War failed to yield significant changes in the role or perception of women in the military. It could be argued that this is the result of the endurance of the image of women as protected. Thus, the Gulf War conformed to the historical pattern set out in Chapters Two and Three in that after its conclusion there was a significant contraction in the role of women. Further, the image of women as protected reasserted itself in postwar discourse. This conclusion is a departure from many popular and scholarly assessments.Dept. of History, Philosophy, and Political Science. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1995 .N36. Source: Masters Abstracts International, Volume: 34-06, page: 2230. Adviser: Martha Lee. Thesis (M.A.)--University of Windsor (Canada), 1996