Sum rules for charmed baryon masses

The measured masses of the three charge states of the charmed $\Sigma_c$ baryon are found to be in disagreement with a sum rule based on the quark model, but relying on no detailed assumptions about the form of the interaction. This poses a significant problem for the charmed baryon sector of the quark model. Other relations among charmed baryon masses are also discussed.Comment: 5 pages, latex, no figure

Comment on Octet Baryon Magnetic Moments in the Chiral Quark Model with Configuration Mixing

The importance of exchange currents, and of conserving isotopic spin at both the quark and baryon levels in application of the chiral quark model to any calculation of baryon magnetic moments is emphasized.Comment: 5 pages, Latex fil

Global variability of water vapor and condensate from SSM/I

In the three years since its launch, the Special Sensor Microwave Imager (SSM/I) provided the beginnings of a data set crucial to the study of the Earth's global hydrologic cycle. Investigations with SSM/I centered largely on two themes: (1) an analysis of the variability in atmospheric moisture as a signature of dynamic and kinematic processes, and (2) development of high quality data sets for determining moisture balance and, eventually, diabatic heating on regional and planetary scales. To date, most of the emphasis has been on the precipitable water field since algorithms for this quantity appear to be the most mature. In addition, researchers began work with liquid water, precipitating ice and ocean surface wind stress fields. The retrievals used in these studies are from algorithms developed by Wentz (RSS Tech Rpt. 1989) and Spencer (1988 JTECH)

Hedge funds and investor protection regulation

A recent Securities and Exchange Commission (SEC) ruling requiring hedge fund advisers to register with the SEC aims to foster conduct and compliance to better protect hedge fund investors. This article focuses on investor protection regulation, considering its goals and likely costs and benefits. After reviewing some alternative regulatory approaches, the author examines the current U.S. regulatory structure for hedge funds, which has, perhaps unwittingly, separated hedge fund investors into two distinct classes -- retail and wholesale -- defined by wealth levels. ; The SEC's recent ruling reflects its concern about the growing "retailization" of hedge funds -- the increasing ability of less qualified (retail) investors to access hedge fund investments -- as general wealth levels rise and as more affordable investments, such as funds of hedge funds (FoFs), proliferate. In addition, institutional investors have increased their investments in hedge funds, exposing even more individual investors, at least indirectly, to a type of risk they may be unfamiliar with. ; The author believes that the costs of increased regulatory protection for hedge fund investors will ultimately prove to outweigh the benefits, and he argues that hedge fund investment strategies be made more, not less, accessible to a broader array of retail investors. In particular, he recommends that the SEC consider authorizing FoFs under a regulatory structure that better enables hedge funds to pursue absolute-return strategies so that retail investors can benefit from them.Hedge funds

Time (in)dependence in general relativity

We clarify the conditions for Birkhoff's theorem, that is, time-independence in general relativity. We work primarily at the linearized level where guidance from electrodynamics is particularly useful. As a bonus, we also derive the equivalence principle. The basic time-independent solutions due to Schwarzschild and Kerr provide concrete illustrations of the theorem. Only familiarity with Maxwell's equations and tensor analysis is required.Comment: Revised version of originally titled "Kinder Kerr", to appear in American Journal of Physic

Mixing of Xi_c and Xi_c' Baryons

The mixing angle between the Xi_c and Xi_c' baryons is shown to be small, with a negligible shift in the Xi_c masses.Comment: One missprint corrected. The numerator of Eq. (12) should read {2[(Sigma_c^{*++}-Sigma_c^{++})-(Xi_c^{*+}-Xi_c^{'+})]} The correct equation was used in the calculation so no other change is mad

Indestructibility of compact spaces

In this article we investigate which compact spaces remain compact under countably closed forcing. We prove that, assuming the Continuum Hypothesis, the natural generalizations to $\omega_1$-sequences of the selection principle and topological game versions of the Rothberger property are not equivalent, even for compact spaces. We also show that Tall and Usuba's "$\aleph_1$-Borel Conjecture" is equiconsistent with the existence of an inaccessible cardinal.Comment: 18 page

Infusion extractor

This invention relates to an apparatus and method of removing desirable constituents from an infusible material by infusion extraction. A piston operating in a first chamber draws a solvent into the first chamber where it may be heated, and then moves the heated solvent into a second chamber containing the infusible material, where infusion extraction takes place. The piston then moves the solvent containing the extract through a filter into the first chamber, leaving the extraction residue in the second chamber. The method is applicable to operation in low or micro-gravity environments