Topology dependent quantities at the Anderson transition

The boundary condition dependence of the critical behavior for the three dimensional Anderson transition is investigated. A strong dependence of the scaling function and the critical conductance distribution on the boundary conditions is found, while the critical disorder and critical exponent are found to be independent of the boundary conditions

Anderson transition in the three dimensional symplectic universality class

We study the Anderson transition in the SU(2) model and the Ando model. We report a new precise estimate of the critical exponent for the symplectic universality class of the Anderson transition. We also report numerical estimation of the $\beta$ function.Comment: 4 pages, 5 figure

Universality of the critical conductance distribution in various dimensions

We study numerically the metal - insulator transition in the Anderson model on various lattices with dimension $2 < d \le 4$ (bifractals and Euclidian lattices). The critical exponent $\nu$ and the critical conductance distribution are calculated. We confirm that $\nu$ depends only on the {\it spectral} dimension. The other parameters - critical disorder, critical conductance distribution and conductance cummulants - depend also on lattice topology. Thus only qualitative comparison with theoretical formulae for dimension dependence of the cummulants is possible

Pulmonary arterial hypertension (PAH) from autopsy study: T-cells, B-cells and mastocytes detection as morphological evidence of immunologically mediated pathogenesis.

Background: Pulmonary arterial hypertension (PAH) is characterized by severe vascular remodelling, resulting in increased pulmonary vascular resistance with cardiac hypertrophy and heart failure. However, the diagnosis of PAH is often inaccurate. Many cases of PAH are incorrectly diagnosed or missed, and they are often associated with death. The aim of this study was to verify the morphological and histological criteria of fatal cases of PAH and evaluate the lymphocytic populations associated to lesions with reactive neo-angiogenesis. Methods: Pulmonary lung sections from 10 cases of sudden unexpected death (SUD) in the absence of previously diagnosed diseases and in an apparent state of well-being, with final histological post autopsy diagnosis of PAH were collected. The pathological findings were compared using ten controls from non-pathological lung from deaths from other causes. The autopsies included 4 males (40%) and 6 females (60%) with an average age of 52.1 ± 10.1 years. Sections stained with hematoxylin and eosin (H&amp;E) were revised for a morphological diagnosis. Subsequently, serial sections were performed and stained with immunohistochemistry for anti-CD20 (B-lymphocytes), anti-CD3 (T-lymphocytes), anti-CD4 (T-helper lumphocytes), anti-CD8 (T-cytotoxic lymphocytes) and anti-CD117/C-Kit (mast cells/MCs) to detect inflammatory infiltrate and different ratios of cell-type. Statistical analysis was conducted using a paired t-test looking at 100 cells in 3 different tissue samples representative of vascular lesion and 3 different random normal lung parenchyma fields without lesion (from 10 normal control lungs), to identify specific lymphocyte subpopulations in inflammatory infiltrates. Results: There was a significant percentage increase of CD20 (p &lt; 0.001), CD8 (p = 0.002), CD4 (p &lt; 0.001), and CD117/C-Kit positive (C-Kit+; p &lt; 0.001) cells mainly detected around wall vessels; while increased MCs positivity and C-Kit+ were observed especially in alveolar septa. In addition, reactive angiomatosis was observed. Conclusions: The inflammatory infiltrate should be included for a correct diagnosis of PAH besides the vascular remodelling. The inflammatory infiltrate seems to be implicated as a main factor in the pathogenesis. This finding is important to rule out secondary pulmonary hypertension, to identify SUDs of unknown causes and to add new elements to the literature that can explain the immunologically related pathogenesis of PAH

Symmetry, dimension and the distribution of the conductance at the mobility edge

The probability distribution of the conductance at the mobility edge, $p_c(g)$, in different universality classes and dimensions is investigated numerically for a variety of random systems. It is shown that $p_c(g)$ is universal for systems of given symmetry, dimensionality, and boundary conditions. An analytical form of $p_c(g)$ for small values of $g$ is discussed and agreement with numerical data is observed. For $g > 1$, $\ln p_c(g)$ is proportional to $(g-1)$ rather than $(g-1)^2$.Comment: 4 pages REVTeX, 5 figures and 2 tables include

Fluctuations of the Lyapunov exponent in 2D disordered systems

We report a numerical investigation of the fluctuations of the Lyapunov exponent of a two dimensional non-interacting disordered system. While the ratio of the mean to the variance of the Lyapunov exponent is not constant, as it is in one dimension, its variation is consistent with the single parameter scaling hypothesis