Mixing-induced anisotropic correlations in molecular crystalline systems

We investigate the structure of mixed thin films composed of pentacene (PEN) and diindenoperylene (DIP) using X-ray reflectivity and grazing incidence X-ray diffraction. For equimolar mixtures we observe vanishing in-plane order coexisting with an excellent out-of-plane order, a yet unreported disordering behavior in binary mixtures of organic semiconductors, which are crystalline in their pure form. One approach to rationalize our findings is to introduce an anisotropic interaction parameter in the framework of a mean field model. By comparing the structural properties with those of other mixed systems, we discuss the effects of sterical compatibility and chemical composition on the mixing behavior, which adds to the general understanding of interactions in molecular mixtures.Comment: 5 pages, 5 figures, accepted by Phys. Rev. Let

Search for Important Weak Interaction Nuclei in Presupernova Evolution

A search is made for the most important electron captures and beta-decays after core silicon buring in massive stars. A nuclear statistical equilibrium code is used to compute isotopic abundances. Electron capture and beta-decay rates are estimated for the 150 most abundant istopes in a simplifiec fashion which generally includes the strongest transitions. These estimates are made for nuclei in the fp-shell and use techniques similar to Fuller, Fowler, & Newman (1982a), and are compared to them. The general behaviour of Y is examined. These methods are then used to follow a typical stellar trajectory, seeking the most important weak interactions during the formation of the iron core. Ranked lists of nuclei are given, to prioritize more detailed studies of individual nuclei. Beta-decays are found to be an important modification to the evolution below Y = 0.4 as the core approaches a state dynamic equilibrium between electron captures and beta-decays

Gamow-Teller strength distributions in fp-shell nuclei

We use the shell model Monte Carlo method to calculate complete 0f1p-shell response functions for Gamow-Teller (GT) operators and obtain the corresponding strength distributions using a Maximum Entropy technique. The approach is validated against direct diagonalization for 48Ti. Calculated GT strength distributions agree well with data from (n,p) and (p,n) reactions for nuclei with A=48-64. We also calculate the temperature evolution of the GT+ distributions for representative nuclei and find that the GT+ distributions broaden and the centroids shift to lower energies with increasing temperature

Analytical in vitro approach for studying cyto- and genotoxic effects of particulate airborne material

In the field of inhalation toxicology, progress in the development of in vitro methods and efficient exposure strategies now offers the implementation of cellular-based systems. These can be used to analyze the hazardous potency of airborne substances like gases, particles, and complex mixtures (combustion products). In addition, the regulatory authorities require the integration of such approaches to reduce or replace animal experiments. Although the animal experiment currently still has to provide the last proof of the toxicological potency and classification of a certain compound, in vitro testing is gaining more and more importance in toxicological considerations. This paper gives a brief characterization of the CULTEX® Radial Flow System exposure device, which allows the exposure of cultivated cells as well as bacteria under reproducible and stable conditions for studying cellular and genotoxic effects after the exposure at the air–liquid or air–agar interface, respectively. A commercial bronchial epithelial cell line (16HBE14o-) as well as Salmonella typhimurium tester strains were exposed to smoke of different research and commercial available cigarettes. A dose-dependent reduction of cell viability was found in the case of 16HBE14o- cells; S. typhimurium responded with a dose-dependent induction of revertants. The promising results recommend the integration of cellular studies in the field of inhalation toxicology and their regulatory acceptance by advancing appropriate validation studies

Electron capture on iron group nuclei

We present Gamow-Teller strength distributions from shell model Monte Carlo studies of fp-shell nuclei that may play an important role in the pre-collapse evolution of supernovae. We then use these strength distributions to calculate the electron-capture cross sections and rates in the zero-momentum transfer limit. We also discuss the thermal behavior of the cross sections. We find large differences in these cross sections and rates when compared to the naive single-particle estimates. These differences need to be taken into account for improved modeling of the early stages of type II supernova evolution

Presupernova collapse models with improved weak-interaction rates

Improved values for stellar weak interaction rates have been recently calculated based upon a large shell model diagonalization. Using these new rates (for both beta decay and electron capture), we have examined the presupernova evolution of massive stars in the range 15-40 Msun. Comparing our new models with a standard set of presupernova models by Woosley and Weaver, we find significantly larger values for the electron-to-baryon ratio Ye at the onset of collapse and iron core masses reduced by approximately 0.1 Msun. The inclusion of beta-decay accounts for roughly half of the revisions, while the other half is a consequence of the improved nuclear physics. These changes will have important consequences for nucleosynthesis and the supernova explosion mechanism.Comment: 4 pages, 2 figure

Practical solution to the Monte Carlo sign problem: Realistic calculations of 54Fe

We present a practical solution to the "sign problem" in the auxiliary field Monte Carlo approach to the nuclear shell model. The method is based on extrapolation from a continuous family of problem-free Hamiltonians. To demonstrate the resultant ability to treat large shell-model problems, we present results for 54Fe in the full fp-shell basis using the Brown-Richter interaction. We find the Gamow-Teller beta^+ strength to be quenched by 58% relative to the single-particle estimate, in better agreement with experiment than previous estimates based on truncated bases.Comment: 11 pages + 2 figures (not included

Перспективы социально-экономического развития Крыма при использовании возобновляемых источников энергии

Социально-экономическое развитие городов и регионов Крыма ориентировано на региональное развитие в зависимости от специфических особенностей каждого из них. Оно должно включать в себя усиление социальной ориентации экономики и решение целого комплекса социально-экономических проблем, обеспечение повышения жизненного уровня населения

PENGARUH STOCK SPLIT TERHADAP HARGA SAHAM DI BURSA EFEK INDONESIA (BEI) (Studi Empiris Pada Perusahaan Yang Melakukan Stock Split Pada Tahun 2015-2018)

In Indonesia, the announcement of a stock split becomes meaningful for investors and potential investors in terms of decision making. Stock split is a form of information that is carried out by issuers to increase the number of shares outstanding. The reason for issuers to do a stock split is that the price of the shares is not too high and is easily reached by investors and can increase liquidity. The purpose of this research is to look at the effect of stock split on stock prices by looking at abnormal return movements and trading volume activity. The population in this study were 58 companies listed on the Indonesian Stock Exchange that did a stock split in 2015-2018, while the sample in this study was 27 companies. Sampling was done by puposive sampling and data analysis techniques using Uji-t paired simple t-test. based on analysis with a significant level of 5%, it can be seen that the abnormal return shows the results of p-value (0.062)> a (0.05), which means that Ho is accepted and Hi is rejected, or there is no influence between abnormal returns before and after the stock split. In stock trading volume (TVA), shows the results of p-value (0.017) <a (0.05) which means that Ho is rejected and Hi is accepted, or there is an influence between trading volume activity before and after the stock split