Coordinate space proton-deuteron scattering calculations including Coulomb force effects

We present a practical method to solve the proton-deuteron scattering problem at energies above the three-body breakup threshold, in which we treat three-body integral equations in coordinate space accommodating long-range proton-proton Coulomb interactions. The method is examined for phase shift parameters, and then applied to calculations of differential cross sections in elastic and breakup reactions, analyzing powers, etc. with a realistic nucleon-nucleon force and three-nucleon forces. Effects of the Coulomb force and the three-nucleon forces on these observables are discussed in comparing with experimental data.Comment: 15 pages, 14 figures, submitted to PR

First-Principles Calculations at Constant Polarization

We develop an exact formalism for performing first-principles calculations for insulators at fixed electric polarization. As shown by Sai, Rabe, and Vanderbilt (SRV) [N. Sai, K. M. Rabe, and D. Vanderbilt, Phys. Rev. B {\bf 66}, 104108 (2002)], who designed an approximate method to tackle the same problem, such an approach allows one to map out the energy landscape as a function of polarization, providing a powerful tool for the theoretical investigation of polar materials. We apply our method to a system in which the ionic contribution to the polarization dominates (a broken-inversion-symmetry perovskite), one in which this is not the case (a III-V semiconductor), and one in which an additional degree of freedom plays an important role (a ferroelectric phase of KNO$_3$). We find that while the SRV method gives rather accurate results in the first case, the present approach provides important improvements to the physical description in the latter cases.Comment: 4 pages, 4 figure

The Dense Plasma Torus Around the Nucleus of an Active Galaxy NGC 1052

A subparsec-scale dense plasma torus around an active galactic nucleus (AGN) is unveiled. We report on very-long-baseline interferometry (VLBI) observations at 2.3, 8.4, and 15.4 GHz towards the active galaxy NGC 1052. The convex spectra of the double-sided jets and the nucleus imply that synchrotron emission is obscured through free--free absorption (FFA) by the foreground cold dense plasma. A trichromatic image was produced to illustrate the distribution of the FFA opacity. We found a central condensation of the plasma which covers about 0.1 pc and 0.7 pc of the approaching and receding jets, respectively. A simple explanation for the asymmetric distribution is the existence of a thick plasma torus perpendicular to the jets. We also found an ambient FFA absorber, whose density profile can be ascribed to a spherical distribution of the isothermal King model. The coexistence of torus-like and spherical distributions of the plasma suggests a transition from radial accretion to rotational accretion around the nucleus.Comment: 10 pages, to appear in Publ. Astron. Soc. Japan, vol.53, No.2 (2001

Numerical Computation of Thermoelectric and Thermomagnetic Effects

Phenomenological equations describing the Seebeck, Hall, Nernst, Peltier, Ettingshausen, and Righi-Leduc effects are numerically solved for the temperature, electric current, and electrochemical potential distributions of semiconductors under magnetic field. The results are compared to experiments.Comment: 4 pages, 7 figures. Submitted to Proceedings of XVII International Conference on Thermoelectrics (ICT98), 1998 Nagoya, Japa

Molecular and Genetic Determinants of Glioma Cell Invasion.

A diffusely invasive nature is a major obstacle in treating a malignant brain tumor, "diffuse glioma", which prevents neurooncologists from surgically removing the tumor cells even in combination with chemotherapy and radiation. Recently updated classification of diffuse gliomas based on distinct genetic and epigenetic features has culminated in a multilayered diagnostic approach to combine histologic phenotypes and molecular genotypes in an integrated diagnosis. However, it is still a work in progress to decipher how the genetic aberrations contribute to the aggressive nature of gliomas including their highly invasive capacity. Here we depict a set of recent discoveries involving molecular genetic determinants of the infiltrating nature of glioma cells, especially focusing on genetic mutations in receptor tyrosine kinase pathways and metabolic reprogramming downstream of common cancer mutations. The specific biology of glioma cell invasion provides an opportunity to explore the genotype-phenotype correlation in cancer and develop novel glioma-specific therapeutic strategies for this devastating disease