Induced spin texture in semiconductor/topological insulator heterostructures

We show that a semiconductor thin film can acquire a non-trivial spin texture due to the proximity effect induced by a topological insulator. The effect stems from coupling to the topological surface states and is present even when the insulator is doped. We propose a semiconductor/topological insulator heterostructure as a device that allows measuring interface properties and probing surface states in uncompensated samples. We also find that the topological insulator surface modes can be significantly broadened and shifted by the presence of metallic contacts.Comment: 6 pages, 2 figures, published versio

Nodal/Antinodal Dichotomy and the Two Gaps of a Superconducting Doped Mott Insulator

We study the superconducting state of the hole-doped two-dimensional Hubbard model using Cellular Dynamical Mean Field Theory, with the Lanczos method as impurity solver. In the under-doped regime, we find a natural decomposition of the one-particle (photoemission) energy-gap into two components. The gap in the nodal regions, stemming from the anomalous self-energy, decreases with decreasing doping. The antinodal gap has an additional contribution from the normal component of the self-energy, inherited from the normal-state pseudogap, and it increases as the Mott insulating phase is approached.Comment: Corrected typos, 4.5 pages, 4 figure

The psychosocial impact of vaginal delivery and cesarean section in primiparous women

The aim of this study was to identify how the method of delivery and birth experience interfere with maternal psychological status early after puerperium. We conducted a prospective study on 148 women after puerperium from November 2017 to January 2018 in Bucur Maternity Hospital. Women that delivered vaginally mobilized in the first 6 hours in 73.7% of the cases, but for cesarean section after 12- 24 hours in 43.6% of the cases. Women described good support from the obstetrician in 58.1% of the cases. 90.5% of the women reported that the method of delivery did not have an impact on infant care and 73% had no lactation problems. The majority described little trauma, in 32.4% of the cases. 70.3% of the patients reported that they wanted to have more children and 59.5% of them desired the same method of delivery. Negative feelings, lactation, and taking care of the baby were not influenced in this study by the method of delivery, but by prematurity of birth and the complications that women experienced at birth

Pheochromocytoma – clinical manifestations, diagnosis and current perioperative management

Pheochromocytoma is a neuroendocrine tumor characterized by the excessive production of catecholamines (epinephrine, norepinephrine, and dopamine). The diagnosis is suspected due to hypertensive paroxysms, associated with vegetative phenomena, due to the catecholaminergic hypersecretion. Diagnosis involves biochemical tests that reveal elevated levels of catecholamine metabolites (metanephrine and normetanephrine). Functional imaging, such as 123I-metaiodobenzylguanidine scintigraphy (123I-MIBG), has increased specificity in identifying the catecholamine-producing tumor and its metastases. The gold-standard treatment for patients with pheochromocytoma is represented by the surgical removal of the tumor. Before surgical resection, it is important to optimize blood pressure and intravascular volume in order to avoid negative hemodynamic events

Spin relaxation in a generic two-dimensional spin-orbit coupled system

We study the relaxation of a spin density injected into a two-dimensional electron system with generic spin-orbit interactions. Our model includes the Rashba as well as linear and cubic Dresselhaus terms. We explicitly derive a general spin-charge coupled diffusion equation. Spin diffusion is characterized by just two independent dimensionless parameters which control the interplay between different spin-orbit couplings. The real-time representation of the diffuson matrix (Green's function of the diffusion equation) is evaluated analytically. The diffuson describes space-time dynamics of the injected spin distribution. We explicitly study two regimes: The first regime corresponds to negligible spin-charge coupling and is characterized by standard charge diffusion decoupled from the spin dynamics. It is shown that there exist several qualitatively different dynamic behaviors of the spin density, which correspond to various domains in the spin-orbit coupling parameter space. We discuss in detail a few interesting phenomena such as an enhancement of the spin relaxation times, real space oscillatory dynamics, and anisotropic transport. In the second regime, we include the effects of spin-charge coupling. It is shown that the spin-charge coupling leads to an enhancement of the effective charge diffusion coefficient. We also find that in the case of strong spin-charge coupling, the relaxation rates formally become complex and the spin/charge dynamics is characterized by real time oscillations. These effects are qualitatively similar to those observed in spin-grating experiments [Weber et al., Nature 437, 1330 (2005)].Comment: 18 pages, 7 figure

Thermodynamic approach on the condensation risk in built environment

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Worldwide energy consumption in residential and public buildings represents almost one third of primary energy. It is one of the larger contributors to fossil fuel use and the carbon dioxide production. Therefore, many countries are currently developing projects for the implementation of measures aimed at energy efficiency for built environment aiming targets of consumption reduction of 15% to 30%. However, less careful implementation of some measures for energy conservation is creating problems of water condensation in both, the newly constructed and the old buildings. Those are problems that created a bad perception regarding energy conservation measures, and also resulted in serious quality problems in built ambient. The main goal of this work is to evaluate the condensation risk in built environment and the influence on the energy consumption of the “inside” thermal insulation placement. A single-zone time-dependent mathematical model is developed based on specific parameters characterizing buildings´ use for commercial purposes. Numerical solutions are determined for commercial buildings over the course of a year. Suitable low cost strategies for energy conservation are developed to avoid condensation and mould growth for a typical classroom at the Federal University of Paraná, Curitiba, PR, Brazil, and to prevent further degradation in problem buildings.dc201

A Polynomial Spectral Calculus for Analysis of DG Spectral Element Methods

We introduce a polynomial spectral calculus that follows from the summation by parts property of the Legendre-Gauss-Lobatto quadrature. We use the calculus to simplify the analysis of two multidimensional discontinuous Galerkin spectral element approximations

Double stripe ordering in Nd0.5Sr0.5MnO3 determined by resonant soft x-ray scattering

7 pages, 8 figures.-- PACS number(s): 75.47.Lx, 78.70.Ck, 71.30.+hWe have studied the low-temperature ordered phase of Nd0.5Sr0.5MnO3 by resonant soft x-ray scattering at the Mn L2,3 edges. Strong resonances were observed at (0 0) and ( 0 0) reflections, which are resolved in momentum space. Azimuthal scans reveal a periodicity for both resonances, the minimum intensity being almost zero. The two reflections show a very different energy dependence which extends in the whole energy region of the Mn L-edge. The (0 0) reflection originates from the anisotropy induced on the d-symmetry projected density of states owing to the local tetragonal distortion at one of the two crystallographic inequivalent Mn sites (the so-called Mn3+ ions in the conventional ionic description). This is similar to the resonance observed at the Mn K edge. We propose that the ( 0 0) reflection, which has not its counterpart either on the Mn K-edge resonant scattering or on the magnetic scattering, is originated by anisotropy of the d-symmetry projected density of the so-called Mn4+ sublattice. In this way, the latter reflection could denote a pure orbital ordering in this sublattice.We are thankful for the financial support from the Spanish CICyT Project No. MAT2005-04562 and from D.G.A. We also acknowledge ESRF and ID08 beamline for granting beam time.Peer reviewe

Momentum relaxation in a semiconductor proximity-coupled to a disordered s-wave superconductor: effect of scattering on topological superconductivity

We study the superconducting proximity effect between a conventional semiconductor and a disordered s-wave superconductor. We calculate the effective momentum relaxation rate in the semiconductor due to processes involving electron tunneling into a disordered superconductor and scattering off impurities. The magnitude of the effective disorder scattering rate is important for understanding the stability of the topological (chiral p-wave) superconducting state that emerges in the semiconductor, since disorder scattering has a detrimental effect and can drive the system into a non-topological state. We find that the effective impurity scattering rate involves higher-order tunneling processes and is suppressed due to the destructive quantum interference of quasi-particle and quasi-hole trajectories. We show that, despite the fact that both the proximity-induced gap and the effective impurity scattering rate depend on interface transparency, there is a large parameter regime where the topological superconducting phase is robust against disorder in the superconductor. Thus, we establish that the static disorder in the superconductor does not suppress the proximity induced topological superconductivity in the semiconductor.Comment: 5 pages, 2 figure