Liquid crystal defects in the Landau-de Gennes theory in two dimensions-beyond the one-constant approximation

We consider the two-dimensional Landau-de Gennes energy with several elastic constants, subject to general $k$-radially symmetric boundary conditions. We show that for generic elastic constants the critical points consistent with the symmetry of the boundary conditions exist only in the case $k=2$. In this case we identify three types of radial profiles: with two, three of full five components and numerically investigate their minimality and stability depending on suitable parameters. We also numerically study the stability properties of the critical points of the Landau-de Gennes energy and capture the intricate dependence of various qualitative features of these solutions on the elastic constants and the physical regimes of the liquid crystal system

Code dependencies of pre-supernova evolution and nucleosynthesis in massive stars: Evolution to the end of core helium burning

Massive stars are key sources of radiative, kinetic and chemical feedback in the Universe. Grids of massive star models computed by different groups each using their own codes, input physics choices and numerical approximations, however, lead to inconsistent results for the same stars. We use three of these 1D codes – genec, kepler and mesa – to compute non-rotating stellar models of 15, 20 and 25 M⊙ and compare their nucleosynthesis. We follow the evolution from the main sequence until the end of core helium burning. The genec and kepler models hold physics assumptions used in large grids of published models. The mesa code was set up to use convective core overshooting such that the CO core masses are consistent with those obtained by genec. For all models, full nucleosynthesis is computed using the NuGrid post-processing tool mppnp. We find that the surface abundances predicted by the models are in reasonable agreement. In the helium core, the standard deviation of the elemental overproduction factors for Fe to Mo is less than 30 per cent – smaller than the impact of the present nuclear physics uncertainties. For our three initial masses, the three stellar evolution codes yield consistent results. Differences in key properties of the models, e.g. helium and CO core masses and the time spent as a red supergiant, are traced back to the treatment of convection and, to a lesser extent, mass loss. The mixing processes in stars remain the key uncertainty in stellar modelling. Better constrained prescriptions are thus necessary to improve the predictive power of stellar evolution models

Investor protection and asset prices

Empirical evidence suggests that investor protection has significant effects on ownership concentration and asset prices. We develop a dynamic asset pricing model to address the empirical regularities and uncover the underlying mechanisms at play. Our model features a controlling shareholder who endogenously accumulates control over a firm, and diverts a fraction of its output. In line with empirical evidence, better investor protection decreases stock holdings of controlling shareholders, increases stock mean-returns, and increases stock return volatilities when ownership concentration is sufficiently high. The model also predicts that better protection increases interest rates and decreases leverage

Electron-Electron Relaxation Effect on Auger Recombination in Direct Band Semiconductors

Influence of electron-electron relaxation processes on Auger recombination rate in direct band semiconductors is investigated. Comparison between carrier-carrier and carrier-phonon relaxation processes is provided. It is shown that relaxation processes are essential if the free path length of carriers doesn't exceed a certain critical value, which exponentially increases with temperature. For illustration of obtained results a typical InGaAsP compound is used

Investor protection and asset prices

Empirical evidence suggests that investor protection significantly affects ownership concentration and asset prices. We develop a dynamic asset pricing model to address the empirical regularities and uncover some of the underlying mechanisms at play. Our model features a controlling shareholder that endogenously accumulates control over a firm, and diverts a fraction of its output. Better investor protection decreases stock holdings of controlling shareholders, increases stock mean returns, and increases stock return volatilities when ownership concentration is sufficiently high, consistent with the related empirical evidence. The model also predicts that better protection increases interest rates and decreases the controlling shareholder's leverage. Received August 14, 2017; editorial decision January 15, 2019 by Editor Stijn Van Nieuwerburgh. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online

Role of hypoxia inducible factor HIF-1α in heart valves

The 2016 Albert Lasker Basic Medical Research Award and subsequently the 2019 Nobel Prize in Physiology or Medicine were awarded to William Kaelin, Jr., Sir Peter Ratcliffe, and Gregg Semenza for their work on how cells sense and adapt to hypoxic conditions. Their work showed that the changes in gene expression, cell metabolism, and tissue remodelling that occur in response to low oxygen concentrations are orchestrated by the transcription factor, hypoxia inducible factor-1α (HIF-1α). While the effects mediated by HIF-1α have been widely studied, its role in heart valves has only recently been investigated. These studies have shown that HIF-1α expression is evident in mechanisms that regulate the structure and function of heart valves. These include embryonic development, the regulation of the extracellular matrix, angiogenesis and the initiation of the calcification process. This review provides a background on the role and function of HIF-1α in response to hypoxia and a discussion of the available evidence of its involvement in the regulation of heart valves in health and disease

Supply Chain Performance Measurement Practices of Indian Industries

In any Industry the Supply chain performance plays a crucial role and it is vital in growth of the industry. Through this study an attempt is made to find some insight to the supply chain performance measurement practices of Indian industries through an exploratory survey. The study reveals almost all the respondents (84%) felt that supply chain performance measurement system employed in their organisation has a clear purpose. Also the study reveals that most supply chain performance measurement system provides high importance to quality measurements and includes both financial and non-financial indicators. The study gave clarity in understanding the objectives of implementing supply chain performance measurement systems and metrics (measures) used in supply chain performance measurement systems The Multivariate analysis revealed three factors emerged from this study are ‘Strategic Orientation’ followed by ‘Internal Focus’ and ‘Motivation and Control’

Modeling of Hysteresis and Magnetization Curves for Hexagonally Ordered Electrodeposited Nanowires

A computational model has been developed to investigate how the magnetostatic interactions affect the hysteresis and magnetization curves for hexagonal arrays of magnetic nanowires. The magnetization coupling between nanowires arises from the stray fields produced by the other nanowires composing the array such that the field at each nanowire is the sum of the external field and the interaction field with the other nanowires. Using only two adjustable parameters: the interaction between nearest neighbors and the width of the Gaussian distribution in switching fields centered around the measuredcoercivity, simulations are compared with the experimentally measuredhysteresis and magnetization curves for electrodepositedCo0.45 Fe0.55 alloy nanowires with diameters from 12 to 48 nm. Excellent agreement is found for all nanowire systems except for the largest diameter arrays where deviations from the Gaussian distribution of switching fields need to be considered