Help Fill the Word Gap!

Our language suffers from a word shortage. There are literally thousands of new phenomena that make modern life increasingly frustrating because we lack the words to aid us in dealing with them. This is because our surroundings change faster than our wordsmiths can provide us with the verbal handles needed to manipulate them

Reas\u27ning But To Err

Americans are great hobbyists. For the unimaginative there are supermarket style hobby shops where they can get pretanned leather, premolded plaster, preselected and prepolished stones for jewelry-making, ad infinitum. Then there are shops for collectors of different kinds, such as philatelists and numismatists. But there are some hobbies for which there are no corner shops, and upon which no financial empires are likely to be built. I know a man who collects railroad locomotives, another who presses the leaves of Chinese trees (which are hard to come by these days), and yet another who collects spider webs and mounts them on black velvet. I, too, am a collector, species logophilia - I collect words

Bose-Einstein Condensates in Superlattices

We consider the Gross--Pitaevskii (GP) equation in the presence of periodic and quasi-periodic superlattices to study cigar-shaped Bose--Einstein condensates (BECs) in such potentials. We examine spatially extended wavefunctions in the form of modulated amplitude waves (MAWs). With a coherent structure ansatz, we derive amplitude equations describing the evolution of spatially modulated states of the BEC. We then apply second-order multiple scale perturbation theory to study harmonic resonances with respect to a single lattice substructure as well as ultrasubharmonic resonances that result from interactions of both substructures of the superlattice. In each case, we determine the resulting system's equilibria, which represent spatially periodic solutions, and subsequently examine the stability of the corresponding wavefunctions by direct simulations of the GP equation, identifying them as typically stable solutions of the model. We then study subharmonic resonances using Hamiltonian perturbation theory, tracing robust spatio-temporally periodic patterns

Revisiting He-like X-ray Emission Line Plasma Diagnostics

A complete model of helium-like line and continuum emission has been incorporated into the plasma simulation code Cloudy. All elements between He and Zn are treated, any number of levels can be considered, and radiative and collisional processes are included. This includes photoionization from all levels, line transfer including continuum pumping and destruction by background opacities, scattering, and collisional processes. The model is calculated self-consistently along with the ionization and thermal structure of the surrounding nebula. The result is a complete line and continuum spectrum of the plasma. Here we focus on the ions of the He I sequence and reconsider the standard helium-like X-ray diagnostics. We first consider semi-analytical predictions and compare these with previous work in the low-density, optically-thin limit. We then perform numerical calculations of helium-like X-ray emission (such as is observed in some regions of Seyferts) and predict line ratios as a function of ionizing flux, hydrogen density, and column density. In particular, we demonstrate that, in photoionized plasmas, the $R$-ratio, a density indicator in a collisional plasma, depends on the ionization fraction and is strongly affected by optical depth for large column densities. We also introduce the notion that the $R$-ratio is a measure of the incident continuum at UV wavelengths. The $G$-ratio, which is temperature-sensitive in a collisional plasma, is also discussed, and shown to be strongly affected by continuum pumping and optical depth as well. These distinguish a photoionized plasma from the more commonly studied collisional case.Comment: 28 pages, 7 figures, accepted to Ap

Global Fits of the CKM Matrix

We report upon the present status of global fits to Cabibbo-Kobayashi-Maskawa matrix.Comment: 3 pages, 3 figures invited talk presented at EPS conference, Aachen July 17-2

Renal homotransplantation with venous outflow or infusion of antigen into the portal vein of dogs or pigs: Transplantation at portal site

Kidneys were transplanted in mongrel dogs so that renal venous drainage was into the portal system of the hosts. Thirty-one recipients were not treated, 11 were given one dose of 3 mg of azathioprine per kg, and 11 were given 2 mg of azathioprine per day. Survival was not statistically increased compared with that in three comparable series in which renal venous drainage was into the vena cava, nor were the histopathological findings favorably altered in the “portal” kidneys. The injection of semisoluble antigen into the portal vein at the same time as renal transplantation at the caval site, had an effect no different from that if the antigen were given systemically during caval site transplantation. The conclusion that drainage of grafts into the portal vein was not beneficial was reached in 20 pigs evenly divided between the portal and vena caval sites, and in 12 pairs of dog to pig or pig to dog xenografts. Thus, none of these experiments has identified an advantage of antigen delivery into the portal as opposed to the systemic venous system. © 1977 by The Williams & Wilkins Co