Non-reciprocal light scattering by lattice of magnetic vortices

We report on experimental study of optical properties of two-dimensional square lattice of triangle Co and CoFe nanoparticles with a vortex magnetization distribution. We demonstrate that intensity of light scattered in diffraction maxima depends on the vorticity of the particles magnetization and it can be manipulated by applying an external magnetic field. The experimental results can be understood in terms of phenomenological theory.Comment: 10 pages, 4 figure

Redistribution of ions within the active layer and upper permafrost, Yamal, Russia

A landslide-affected slope was chosen to study the ionic migration in the active layer and upper portion of permafrost. The research was conducted in two stages, in 1994 and 2001. Several boreholes, in dry and wet environments of the shearing surface of a 1989-landslide, were drilled. A background borehole on an undisturbed site was sampled as well. Each sample, collected from the core, underwent a conventional chemical cation-anion analysis. The results showed desalinization of the active layer and upper permafrost, which occurred in 7 years. Different migration rates noted for various salts determine change of ionic composition from marine pattern to continental, because mobile ions are washed away by surface and subsurface runoff, while the less mobile ones are accumulating in the upper portion of the active layer due to capillary rise and at the active layer base on a geochemical barrier

Anti-vortex state in cross-like nanomagnets

We report on results of computer micromodelling of anti-vortex states in asymmetrical cross-like ferromagnetic nanostructures and their practical realization. The arrays of cobalt crosses with 1 mkm branches, 100 nm widths of the branches and 40 nm thicknesses were fabricated using e-beam lithography and ion etching. Each branch of the cross was tapered at one end and bulbous at the other. The stable formation of anti-vortex magnetic states in these nanostructures during magnetization reversal was demonstrated experimentally using magnetic force microscopy.Comment: 19 pages, 9 figure

ВЛИЯНИЕ ТОНАЛЬНОСТИ НОВОСТЕЙ НА КУРС БИТКОИНА

The authors assess the impact of the emotional tonality of bitcoin news on its exchange rate. In particular, we studied the hypothesis of the impact of the readability index of the news text on the volatility of bitcoin. Despite the fact that excessive volatility threatens bitcoin not to become a successful currency, many scientists are interested in the determinants of such volatility. Factors such as speculative investments or the attention of the society are the drivers of the volatility of the exchange rate of bitcoin. In this regard, the question of studying the impact of news on the bitcoin exchange rate is relevant. The purpose of this paper is to assess the impact of the emotional tonality of bitcoin news on its exchange rate. The empirical base of the study was quite extensive since it includes more than 1330 news from the Thomson Reuters information base for the period from 19.08.2011 to 16.08.2016 on the bitcoin market. The research methodology includes the sentiment analysis conducted by using the dictionary MacDonald and Loughran and also the analysis of the interdependence of time series-based causal analysis using the test of Granger causation. We present three hypotheses about the impact of news on the bitcoin exchange rate. During the study, two of them were confirmed. We proved the first hypothesis that the negative news had a more significant impact than positive ones, taking into account the five time-lags. The second hypothesis about the impact of positive tonality in the news on the bitcoin exchange rate, using the Granger test for causation, was not confirmed, since the positive values of this test were obtained in two time-lags out of five. We can confirm that the third hypothesis was proved — the high readability index has an impact on the bitcoin volatility for the entire studied period, taking into account all five time-lags. Thus, the assumption about the impact of the emotional tonality of news on the bitcoin exchange rate can be confirmed.Оценивается влияние эмоциональной тональности новостей о биткоине на его курс. В частности, исследуется, влияет ли индекс читабельности текста новостей на волатильность биткоина. Несмотря на то что чрезмерная волатильность угрожает биткоину не стать успешной валютой, многие ученые заинтересованы в детерминантах такой волатильности. Такие факторы, как спекулятивные инвестиции или внимание общества, являются драйверами изменчивости курса биткоина. В связи с этим вопрос исследования влияния новостей на курс биткоина является актуальным. Цель данной работы состоит в том, чтобы оценить влияние эмоциональной тональности новостей о биткойне на его курс. Эмпирическая база исследования довольно объемная, поскольку включает в себя более 1330 новостей из информационной базы Thomson Reuters за период с 19.08.2011 по 16.08.2016 г. по рынку биткоина. Методология исследования включает анализ тональности, проведенный с использованием словаря МакДональда и Лоугрэна, также проведен анализ взаимозависимости временных рядов на основе каузального анализа с применением теста Грэнджера на причинность.В статье поставлены три гипотезы о влиянии новостей на курс биткоина. В ходе исследования получили подтверждение две из них. Доказана первая гипотеза о более значительном влиянии негативных новостей, чем позитивных с учетом пяти лагов. Вторая гипотеза о влиянии положительной тональности в новостях на курс в результате применения теста Грэнджера на причинность не подтвердилась, поскольку положительные значения данного теста были получены в двух лагах из пяти. Также была доказана третья гипотеза о том, что высокий индекс читабельности оказывает влияние на волатильность биткоина за весь изученный период с учетом всех пяти лагов. Таким образом, предположение о влиянии эмоционального освещения новостей на курс биткоина подтвердилось

Barium Titanate Nanoparticles for Biomarker Applications

A tetragonal crystal structure is required for barium titanate nanoparticles to exhibit the nonlinear optical effect of second harmonic light generation (SHG) for use as a biomarker when illuminated by a near-infrared source. Here we use synchrotron XRD to elucidate the tetragonal phase of commercially purchased tetragonal, cubic and hydrothermally prepared barium titanate (BaTiO3) nanoparticles by peak fitting with reference patterns. The local phase of individual nanoparticles is determined by STEM electron energy loss spectroscopy (EELS), measuring the core-loss O K-edge and the Ti L3-edge energy separation of the t2g, eg peaks. The results show a change in energy separation between the t2g and eg peak from the surface and core of the particles, suggesting an intraparticle phase mixture of the barium titanate nanoparticles. HAADF-STEM and bright field TEM-EDX show cellular uptake of the hydrothermally prepared BaTiO3 nanoparticles, highlighting the potential for application as biomarkers