Results of the 1997 Illinois Deer Hunter Survey

Administrative ReportReport issued on: July 17, 200

Normal subgroups of diffeomorphism and homeomorphism groups of R^n and other open manifolds

We determine all the normal subgroups of the group of C^r diffeomorphisms of R^n, r = 1,2,...,infinity, except when r=n+1 or n=4, and also of the group of homeomorphisms of R^n (r=0). We also study the group A_0 of diffeomorphisms of an open manifold M that are isotopic to the identity. If M is the interior of a compact manifold with nonempty boundary, then the quotient of A_0 by the normal subgroup of diffeomorphisms that coincide with the identity near to a given end e of M is simple.Comment: This version corrects an error regarding the diffeomorphism groups of R^1, since the line has two ends, in contrast to higher dimension

Zero temperature black holes in semiclassical gravity

The semiclassical Einstein equations are solved to first order in $\epsilon = \hbar/M^2$ for the case of an extreme or nearly extreme Reissner-Nordstr\"{o}m black hole perturbed by the vacuum stress-energy of quantized free fields. It is shown that, for realistic fields of spin 0, 1/2, or 1, any zero temperature black hole solution to the equations must have an event horizon at $r_h < |Q|$, with $Q$ the charge of the black hole. It is further shown that no black hole solutions with $r_h < |Q|$ can be obtained by solving the semiclassical Einstein equations perturbatively.Comment: 7 pages, to appear in the Proceedings of the Ninth Marcel Grossmann Meeting, change in titl

Explant Analysis of Total Disc Replacement

Explant analysis of human disc prostheses allow early evaluation of the host response to the prosthesis and the response of the prosthesis from the host. Furthermore, early predictions of failure and wear can be obtained. Thus far, about 2-3% of disc prostheses have been removed. Observed wear patterns are similar to that of appendicular prostheses including abrasions/scratching, burnishing, surface deformation, fatigue, and embedded debris. Chemically the polymeric components have shown little degradation in short-term implantation. In metal on metal prostheses the histologic responses consist of large numbers of metallic particles with occasional macrophages and giant cells. Only rare cases of significant inflammatory response from polymeric debris have been seen

Correlation patterns from massive phonons in 1+1 dimensional acoustic black holes: A toy model

Transverse excitations in analogue black holes induce a mass like term in the longitudinal mode equation. With a simple toy model we show that correlation functions display a rather rich structure characterized by groups of parallel peaks. For the most part the structure is completely different from that found in the massless case.Comment: 40 pages, 13 figures. Minor changes and corrections Phys. Rev. D versio