Vortex in a relativistic perfect isentropic fluid and Nambu Goto dynamics

By a weak deformation of the cylindrical symmetry of the potential vortex in a relativistic perfect isentropic fluid, we study the possible dynamics of the central line of this vortex. In "stiff" material the Nanbu-Goto equations are obtainedComment: 11 pages, Accepted for publication in Physical Review

Job and Career Resources: Not Just for Public Libraries

This article examines the process of creating, from idea to implementation, a career resource center at the Georgia College and State University Library and Instructional Technology Center. This resource center consists of a collection of the latest sources of information on strategies for successful career matching and job searching, in addition to a computer with bookmarked websites for easy navigation of selected helpful websites and informative articles

The Origin of the Magellanic Stream

SHORTENED ABSTRACT: We present numerical investigations designed to critically test models of the origin of the Magellanic Stream. The most developed model is the tidal model which fails to reproduce several of its characteristic properties. We suggest an alternative model for the origin of the Stream which can explain all of its observed features and dynamics, as well as provide a strong constraint on the distribution of gas within the halo of the Milky Way. We propose that the Stream consists of material which was ram-pressure stripped from the Magellanic System during its last passage through an extended ionized disk of the Galaxy. This collision took place some 500 million years ago at a galacto-centric distance of about 65 kpc, and swept $\sim 20$\% of the least bound HI into the Stream. The gas with the lowest column density lost the most orbital angular momentum, and is presently at the tip of the Stream, having fallen to a distance of $\sim 20$ kpc from the Milky Way attaining a negative velocity of 200 \kms. To prevent the stripped material from leading the Magellanic Clouds and attaining too large an infall velocity, we postulate the existence of an extended dilute halo of diffuse ionized gas surrounding the Milky Way. If the halo gas is at the virial temperature of the potential well of the Milky Way, its thermal emission would contribute $\sim$ 40\% of the observed diffuse background radiation in the 0.5-1.0 keV (M) band, consistent with recent ROSAT measurements as well as pulsar dispersion measures. Ram pressure strippingComment: 20 pages in TeX format. Please request hardcopy of plots, tables and text from B

Ben A. Davis, Jr. to Dr. Silver, 9 February 1961

Professional correspondenc

The Return of a Judicial Artifact?: How the Supreme Court Could Examine the Question of the Nondelegation Doctrine’s Place in Future Cases

Undergraduate Textual or Investigativ

Colourful TFNP and Propositional Proofs

Recent work has shown that many of the standard TFNP classes - such as PLS, PPADS, PPAD, SOPL, and EOPL - have corresponding proof systems in propositional proof complexity, in the sense that a total search problem is in the class if and only if the totality of the problem can be efficiently proved by the corresponding proof system. We build on this line of work by studying coloured variants of these TFNP classes: C-PLS, C-PPADS, C-PPAD, C-SOPL, and C-EOPL. While C-PLS has been studied in the literature before, the coloured variants of the other classes are introduced here for the first time. We give a family of results showing that these coloured TFNP classes are natural objects of study, and that the correspondence between TFNP and natural propositional proof systems is not an exceptional phenomenon isolated to weak TFNP classes. Namely, we show that: - Each of the classes C-PLS, C-PPADS, and C-SOPL have corresponding proof systems characterizing them. Specifically, the proof systems for these classes are obtained by adding depth to the formulas in the corresponding proof system for the uncoloured class. For instance, while it was previously known that PLS is characterized by bounded-width Resolution (i.e. depth 0.5 Frege), we prove that C-PLS is characterized by depth-1.5 Frege (Res(polylog(n)). - The classes C-PPAD and C-EOPL coincide exactly with the uncoloured classes PPADS and SOPL, respectively. Thus, both of these classes also have corresponding proof systems: unary Sherali-Adams and Reversible Resolution, respectively. - Finally, we prove a coloured intersection theorem for the coloured sink classes, showing C-PLS ? C-PPADS = C-SOPL, generalizing the intersection theorem PLS ? PPADS = SOPL. However, while it is known in the uncoloured world that PLS ? PPAD = EOPL = CLS, we prove that this equality fails in the coloured world in the black-box setting. More precisely, we show that there is an oracle O such that C-PLS^O ? C-PPAD^O ? C-EOPL^O. To prove our results, we introduce an abstract multivalued proof system - the Blockwise Calculus - which may be of independent interest

The Preparation and Properties of Furyl Phenyl Ketimine

This ketimine has been prepared through the condensation of furonitrile with magnesium phenyl bromide, followed by treatment with ice and ammonium chloride at about -15 degrees C. The hydrochloride, a white solid, is rather quickly hydrolyzed to the corresponding ketone, benzoyl furane. The velocity of this hydrolysis and the basic strength of the free ketimine base are determined