Residence choices of Hispanic neighborhoods in Nevada

A well-known characteristic of Hispanic in the U.S. is their tendency to concentrate their settlement area in distinct locations. This study merges aggregate data of localities with micro observations to estimate the joint decisions of residential location and homeownership choice for Hispanics. To address the possibility that the disturbances in the regression may be correlated within groups, we apply a bivarite probit framework clustered by localities (PUMAs), using the Public Use Micro Statistics of Census 2000 data for Nevada. The results suggests that Hispanics choose to live in Hispanic enclaves are characterized by lower income, less English fluency, lower educational attainments and recent migration. Assessing the interaction of the homeownership decisions and location choice, we find that these two residential decisions are simultaneously determined and they have significantly positive effects on each other

Levinson theorem in two dimensions

A two-dimensional analogue of Levinson's theorem for nonrelativistic quantum mechanics is established, which relates the phase shift at threshold(zero momentum) for the $m$th partial wave to the total number of bound states with angular momentum $m\hbar(m=0,1,2,...)$ in an attractive central field.Comment: LaTeX, no figur

Levinson theorem for Dirac particles in one dimension

The scattering of Dirac particles by symmetric potentials in one dimension is studied. A Levinson theorem is established. By this theorem, the number of bound states with even (odd) parity, $n_+$ ($n_-$), is related to the phase shifts $\eta_+(\pm E_k)$ [$\eta_-(\pm E_k)$] of scattering states with the same parity at zero momentum as follows: $$\eta_\pm(\mu)+\eta_\pm(-\mu)\pm{\pi\over 2}[\sin^2\eta_\pm(\mu) -\sin^2\eta_\pm(-\mu)]=n_\pm\pi.$$ The theorem is verified by several simple examples.Comment: REVTeX, 17 pages, no figur

On the partial wave amplitude of Coulomb scattering in three dimensions

The partial wave series for the Coulomb scattering amplitude in three dimensions is evaluated in a very simple way to give the closed result.Comment: revtex, 6 pages, no figur

Anisotropic harmonic oscillator in a static electromagnetic field

A nonrelativistic charged particle moving in an anisotropic harmonic oscillator potential plus a homogeneous static electromagnetic field is studied. Several configurations of the electromagnetic field are considered. The Schr\"odinger equation is solved analytically in most of the cases. The energy levels and wave functions are obtained explicitly. In some of the cases, the ground state obtained is not a minimum wave packet, though it is of the Gaussian type. Coherent and squeezed states and their time evolution are discussed in detail.Comment: revtex, 14 pages, no figure, two more references adde