U.S. Election Assistance Commission Urban-Rural Study: Final Report

In May, the U.S. Election Assistance Commission released a report comparing election administration in urban and rural jurisdictions. The survey uncovered more similarities than differences, in part because many small, urban jurisdictions have more in common with rural offices than with very large metropolitan ones. The size of the registered voter population seemed to influence administration more than did the degree of urbanization.The report was based on a national survey of local election administrators that focused on voter-outreach efforts and office personnel -- topics identified by a working group of election officials and researchers as likely to vary based on a jurisdiction's urbanization

A conjectural generating function for numbers of curves on surfaces

I give a conjectural generating function for the numbers of $\delta$-nodal curves in a linear system of dimension $\delta$ on an algebraic surface. It reproduces the results of Vainsencher for the case $\delta\le 6$ and Kleiman-Piene for the case $\delta\le 8$. The numbers of curves are expressed in terms of five universal power series, three of which I give explicitly as quasimodular forms. This gives in particular the numbers of curves of arbitrary genus on a K3 surface and an abelian surface in terms of quasimodular forms, generalizing the formula of Yau-Zaslow for rational curves on K3 surfaces. The coefficients of the other two power series can be determined by comparing with the recursive formulas of Caporaso-Harris for the Severi degrees in $\P_2$. We verify the conjecture for genus 2 curves on an abelian surface. We also discuss a link of this problem with Hilbert schemes of points.Comment: amslatex 13 page

X-ray and optical observations of three clusters of galaxies: Abell 901, Abell 1437, and Abell 3570

We analyse three clusters of galaxies, Abell 901 (z=0.17), Abell 1437 (z=0.13) and Abell 3570 (z=0.037). They have low to intermediate X-ray fluxes and an irregular morphology in the ROSAT All-Sky Survey (RASS). These clusters are chosen to test the abilities and limitations of the RASS in terms of cluster fluxes and cluster morphologies. Therefore some ``worst'' cases are used here. X-ray observations with the ROSAT/HRI and optical spectroscopic observations are carried out. The ROSAT/HRI observations, which have a much better spatial resolution than the RASS, reveal in two of the three cases a significantly different morphology than seen in the RASS. The reasons are point sources which could not be resolved in the RASS and were therefore confused with the cluster emission. For A3570 we could confirm the relaxed state of the cluster by the optical determination of a small velocity dispersion. In the cluster with the lowest flux (Abell 901) the countrate measurement is strongly affected by point sources, in the two other cases the countrate measurements of the RASS are reliable, i.e. they are reproduced by the ROSAT/HRI measurement. We conclude that for clusters with a flux of a few times 10^{-12} erg/cm^2/s or smaller, which show at the same time a non-relaxed morphology, the flux measurement of the RASS can be seriously affected by fore- or background sources. We point out that an all-sky survey of a second ABRIXAS mission would provide a much clearer source distinction for low-flux clusters and thus a much improved countrate determination.Comment: 8 pages (incl. 6 figures), accepted for publication in A&A (Suppl.

On a filtered multiplicative basis of group algebras

Let $K$ be a field of characteristic $p$ and $G$ a nonabelian metacyclic finite $p$-group. We give an explicit list of all metacyclic $p$-groups $G$, such that the group algebra $KG$ over a field of characteristic $p$ has a filtered multiplicative $K$-basis. We also present an example of a non-metacyclic 2-group $G$, such that the group algebra $KG$ over any field of characteristic 2 has a filtered multiplicative $K$-basis.Comment: 10 pages, AMS-Te

Extension of the Brinkman-Rice picture and the Mott transition

In order to explain the metal-Mott-insulator transition, the Brinkman-Rice (BR) picture is extended. In the case of less than one as well as one electron per atom, the on-site Coulomb repulsion is given by U={kappa}{rho}^2U_c by averaging the electron charge per atom over all atomic sites, where {kappa} is the correlation strength of U, {rho} is the band filling factor, and U_c is the critical on-site Coulomb energy. The effective mass of a quasiparticle is found to be m*/m=1/{1-{kappa}^2{rho}^4} for 0<{kappa}{rho}^2<1 and seems to follow the heat capacity data of Sr_{1-x}La_xTiO_3 and YBa_2Cu_3O_{7-delta} at {kappa}=1 and 0<{kappa}{rho}^2<1. The Mott transition of the first order occurs at {kappa}{rho}^2=1 and a band-type metal-insulator transition takes place at {kappa}{rho}^2=0. This Mott transition is compared with that in the d=infinity Hubbard model. The effective mass for 2D-DOS instead of the vHs can be used for the mechanism of high T_c superconductivity.Comment: RevTex, Physica C, Vol. 341-348, 259-260 (2000

Neutrino Experiments : Highlights

This article consists of two parts. The first section presents the highlights on the goals of neutrino physics, status of the current neutrino experiments and future directions and program. The second section describes the theme, program and research efforts for the TEXONO Collaboration among scientists from Taiwan and China.Comment: 7 pages, 7 figure; Invited Contributions to the Proceedings of ``The Fifth International Workshop on Particle Physics Phenomenology (PPP2000)'

Critical exponents at the superconductor-insulator transition in dirty-boson systems

I obtain the inverse of the correlation length exponent at the superfluid-Bose glass quantum critical point as a series in small parameter $\sqrt{d-1}$, with d being the dimensionality of the system, and compute the first two terms using a novel field-theoretic technique. For d=2 I find $\nu_s = 0.81$ and $\nu_c = 1.03$, for short-range and Coulomb interactions between bosons, respectively. When combined with the exact values of the dynamical critical exponents $z_s = d$ and $z_c = 1$, these results are in quantitative agreement with the experiments on onset of superfluidity in $^4 He$ in porous glasses, and on superconductor-insulator transition in homogeneous metallic films, in support of the dirty-boson theory fot the latter. Higher-order calculation of the exponents and of the universal conductivity is discussed.Comment: 4 pages, RevTex, eq. 10 correcte