FUSE Observations of the Cygnus Loop: OVI Emission from a Nonradiative Shock

We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of a Balmer filament in the northeast region of the Cygnus Loop supernova remnant. The data consist of one spectrum obtained through the 30"x30" (LWRS) aperture and three spectra at adjacent positions obtained through the 4"x20" (MDRS) aperture. The nonradiative shocks in the region giving rise to these faint optical filaments produce strong OVI 1032,1038 emission, which is detected in all the spectra. The OVI emission is resolved by FUSE into a strong component centered at 0 km/s, and weaker components centered at +/- 140 km/s. The MDRS spectra allow us to study the variation of OVI emission in the post-shock structure. We find that the zero velocity emission is associated directly with the Balmer filament shock, while the high velocity emission comes from a more uniformly distributed component elsewhere along the line of sight. We also find that the shocks producing the emission at +/- 140 km/s have velocities between 180 km/s and 220 km/s, if we assume that the ram pressure driving them is the same as for the zero velocity component shock. In the context of the cavity model for the Cygnus Loop, the interaction of the blast wave with the spherical shell that forms most of the cavity wall can naturally give rise to the similar red and blue-shifted components that are observed.Comment: LaTeX uses aaspp4.sty, 18 pages + 5 PostScript figures. Accepted for publication in the Astrophysical Journa

Session Types in a Linearly Typed Multi-Threaded Lambda-Calculus

We present a formalization of session types in a multi-threaded lambda-calculus (MTLC) equipped with a linear type system, establishing for the MTLC both type preservation and global progress. The latter (global progress) implies that the evaluation of a well-typed program in the MTLC can never reach a deadlock. As this formulated MTLC can be readily embedded into ATS, a full-fledged language with a functional programming core that supports both dependent types (of DML-style) and linear types, we obtain a direct implementation of session types in ATS. In addition, we gain immediate support for a form of dependent session types based on this embedding into ATS. Compared to various existing formalizations of session types, we see the one given in this paper is unique in its closeness to concrete implementation. In particular, we report such an implementation ready for practical use that generates Erlang code from well-typed ATS source (making use of session types), thus taking great advantage of the infrastructural support for distributed computing in Erlang.Comment: This is the original version of the paper on supporting programming with dyadic session types in AT

Bureaucratic influence in congressional roll-call voting

The focus of this dissertation is on one of the many relationships that exist between the bureaucracy and government: decision-making by elected representatives and the political influence of government employees on their decision-making. Specifically, it is with bureaucrats and the degree to which they may utilize political influence to create a disproportionate influence over government policy and decision-making in the United States House of Representatives. I argue that the inherent qualities of bureaucrats suggest that they are significant and influential constituency for representatives. They are an identifiable constituency to representatives, and have the means and opportunity to wield political influence. Therefore, I suggest that bureaucrats are a reelection constituency for representatives. My analysis suggests that representatives do indeed respond to government employees as a reelection constituency. The findings illustrate several conclusions. First, bureaucrats have a moderating effect on the roll-call fiscal conservatism of representatives. Secondly, the election cycle is revealed to have a mediating effect on this bureaucratic effect. I demonstrate that representatives are more responsive to bureaucrats in the midterm congresses than in presidential congresses. Finally, I identify a party effect on bureaucratic influence that suggests that Republicans representatives that are more attentive to government employees than Democrats. I suggest that Democratic House members are already relatively liberal in their roll-call behavior on fiscal policy and a natural constituency for bureaucrats. Conversely, Republicans may discover that they can cultivate this core constituency for their reelection efforts by become more moderate in their roll-call fiscal conservatism

Extraction of energy from gravitational waves by laser interferometer detectors

In this paper we discuss the energy interaction between gravitational waves and laser interferom- eter gravitational wave detectors. We show that the widely held view that the laser interferometer gravitational wave detector absorbs no energy from gravitational waves is only valid under the approximation of a frequency-independent optomechanical coupling strength and a pump laser without detuning with respect to the resonance of the interferometer. For a strongly detuned interferometer, the optical-damping dynamics dissipates gravitational wave energy through the interaction between the test masses and the optical field. For a non-detuned interferometer, the frequency-dependence of the optomechanical coupling strength causes a tiny energy dissipation, which is proved to be equivalent to the Doppler friction raised by Braginsky et.al.Comment: 20 pages, 7 figure

A high resolution UV absorption spectrum of supernova ejecta in SN1006

We report a high resolution, far-ultraviolet, STIS E140M spectrum of the strong, broad Si II, III, and IV features produced by the ejecta of SN1006 seen in absorption against the background Schweizer-Middleditch star. The spectrum confirms the extreme sharpness of the red edge of the redshifted Si II 1260 A feature, supporting the idea that this edge represents the location of the reverse shock moving into the freely expanding ejecta. The expansion velocity of ejecta at the reverse shock is measured to be 7026 +-3(relative) +-10(absolute) km/s. If the shock model is correct, then the expansion velocity should be decreasing at the observable rate of 2.7 +-0.1 km/s per year. The pre-shock velocity, post-shock velocity, and post-shock velocity dispersion are all measured from the Si II 1260 A feature, and consistency of these velocities with the shock jump conditions implies that there is little or no electron heating in this fast (2680 km/s) Si-rich shock.Comment: 9 pages, 5 embedded postscript fig

The Topographical Influences on the Campaigns in Middle and West Tennessee during the First Year of the Civil War

Preface: This study is an attempt to evaluate the role played by topography in the results of the campaign in West and Middle Tennessee during the first year of the War Between the States. In mid-nineteenth century America, roads were poor and communication was extremely slow. The use of the telegraph was not yet widespread; mountains and rivers still presented formidable barriers to travel, and the chief means of movement for troops was by railroad, steamboat, horseback, and on foot. As the main source for primary materials for this thesis I have relied on the War of the Rebellion, A Compilation of the Official Records of the Union and Confederate Armies. The Atlas which accompanies these records has also been invaluable for material relating to troop movements and positions as well as for use as a source for portions of the maps included in this project. It is hoped that the maps will aid the reader in understanding the topography of the localities with which the study is concerned. The maps are not drawn to scale but are used to show troop movements in respect to prominent relief features and political boundaries. I am deeply indebted to Doctor Stanley J. Folmsbee of the University of Tennessee History Department, who suggested the subject of this thesis and provided inspiration and guidance during its preparation. I would also like to express my appreciation to Doctor Ralph W. Haskins and Doctor H. C. Amick, whose painstaking examination and helpful comments have contributed greatly to this study

The Woodbine Formation

Geological Science

The Schwarz boundary value problem for boundary values in the sense of distributions

We construct solutions to the Schwarz boundary value problem on the unit disk and the upper half-plane when the boundary condition is with respect to boundary values in the sense of distributions.Comment: currently under revie