Properties of the Young Milky Way Globular Cluster Whiting 1 from Near-Infrared Photometry

Whiting 1 is a member of the fast-growing group of young globular clusters in the Milky Way halo. Preliminary estimates of its fundamental parameters have been provided using optical photometry and low resolution spectroscopy. In an attempt to strengthen our knowledge of Whiting 1, in this study we employ a complementary approach. Isochrone fitting method was applied on the Near-Infrared Color-Magnitude Diagram and yields an age t=5.7$\pm$0.3 Gyr, metallicity $z$=0.006$\pm$0.001 ([Fe/H]=$-$0.5$\pm$0.1) and distance modulus $(m-M)_0$=17.48$\pm$0.10. Our results confirm that Whiting 1 is a young and moderately metal-rich globular cluster. It is one of the youngest from the Sgr dSph. We fitted an Elson, Fall and Freeman (EFF) profile to the near-infrared number counts, and measured cluster core radius $r_c$=9.1${\prime\prime}$$\pm$3.9${\prime\prime}$. Two probable eclipsing variables in the cluster were found from multi-epoch $V$ band photometry. Finally, an unknown galaxy cluster was identified on our $K$ vs. $(J-K)$ color-magnitude diagram. It has a redshift z$\sim$1, and it is located at about 1${\prime}$ from the center of Whiting 1 at $\alpha_{J2000}=02^{h} 02^{m} 56.6^{s}$, $\delta_{J2000}=-03^{\circ} 16{\prime} 09{\prime\prime}$, contaminating the cluster photometry.Comment: Accepted for publication in MNRAS, 6 pages, 8 figure

Intranight variability of 3C 454.3 during its 2010 November outburst

Context. 3C 454.3 is a very active flat spectrum radio quasar (blazar) that has undergone a recent outburst in all observed bands, including the optical. Aims. In this work we explore the short-term optical variability of 3C 454.3 during its outburst by searching for time delays between different optical bands. Finding one would be important for understanding the evolution of the spectrum of the relativistic electrons, which generate the synchrotron jet emission. Methods. We performed photometric monitoring of the object by repeating exposures in different optical bands (BVRI). Occasionally, different telescopes were used to monitor the object in the same band to verify the reliability of the smallest variations we observed. Results. Except on one occasion, where we found indications of a lag of the blue wavelengths behind the red ones, the results are inconclusive for most of the other cases. There were either no structures in the light curves to be able to search for patterns, or else different approaches led to different conclusions.Comment: 4 pages, 4 figures. Accepted for publication in A&

METHODOLOGICAL PROBLEMS OF STATISTICAL STUDY OF REGIONAL TOURISM AND TOURIST EXPENDITURE

1 The aim of the work is the analysis of the problems of regional tourism statistics. The subject of the research is the tourism expenditure, the specificity of their recording and modeling

Methodological problems of statistical study of regional tourism and tourist expenditure

The aim of the work is the analysis of the problems of regional tourism statistics. The subject of the research is the tourism expenditure, the specificity of their recording and modeling. The methods of statistical observation and factor analysis are used. The article shows the features and directions of statistical methodology of tourism. A brief review of international publications on statistical studies of tourist expenditure is made. It summarizes the data from different statistical forms and shows the positive and negative trends in the development of tourism in Russia. It is concluded that the tourist industry in Russia is focused on outbound tourism rather than on inbound or internal. The features of statistical accounting and statistical analysis of tourism expenditure in Russian and international statistics are described. To assess the level of development of regional tourism the necessity of use the coefficient of efficiency of tourism. The reasons of the prevalence of imports over exports of tourism services are revealed using the data of the balance of payments. This is due to the raw material orientation of Russian exports and low specific weight of the account "Services" in the structure of the balance of payments. The additive model is also proposed in the paper. It describes the influence of three factors on the changes in tourist expenditure. These factors are the number of trips, the cost of a trip and structural changes in destinations and travel purposes. On the basis of the data from 2012-2013 we estimate the force and the direction of the influence of each factor. Testing of the model showed that the increase in tourism exports caused by the combined positive impact of all three factors, chief of which is the growing number of foreigners who visited Russia during the concerned period. © 2015 The Journal of Economic Theory

On the Possible Application of Tubercles on Pumping Impeller to Decrease Hydraulic Resistance

This article is devoted to the biomimicry engineering approaches. The main idea of a tubercle technology and its advantage are presented. The conveniences of the usage of pumping impellers with tubercles in the main pipeline transport were formulated. It was also suggested to make profound learning of application of the tubercle technology in rotating devices

Разработка методики энергетической оценки эксплуатационных режимов работы силового электрооборудования

RU: В данной статье на базе исследования потерь активной мощности в асинхронном электродви- гателе с короткозамкнутым ротором в функции загрузки на валу и температуры окружающей среды и теплового износа его изоляции разработана методика единой оценки процессов потерь электрической энергии и расхода ресурса изоляционной конструкции в электродвигателе в еди- ницах энергии

Индекс финансового страха на рынке цифровых финансовых активов

The relevance of the research topic is due to the increasing role of non-traditional financial instruments that contribute to financial instability. Therefore, various indicators are required to reflect the situation in the digital financial assets market, the volatility quotes, and the level of investor confidence. The aim of the study is to develop and test on empirical data a generalized indicator of financial instability (financial fear index) in the digital financial assets market. The novelty of the research lies in the adaptation of the classic model of building the volatility index to the cryptocurrency market.The authors use statistical methods for collecting and processing data, analyzing time series, weighing, designing economic indicators. The paper summarizes the results of modern research on the correlation between digitalization and financial instability. The authors conclude that at certain short periods of 2020 the ruble-dollar volatility was comparable or even higher than the ruble-bitcoin one. In addition, there is much less fear and uncertainty in the cryptocurrency market today than there was at the end of 2018. The main result of the study is the financial fear index model based on the method of calculating the weighted average option price of the underlying asset and hedging of price risks. The model has been tested using data on the bid and ask prices of cryptocurrencies at a specific point in time. Estimates have been obtained indicating the growing instability in the digital financial asset market. The authors offer recommendations regarding the index threshold values, which indicate the level of investors’ fear.Актуальность темы исследования диктуется возрастающей ролью нетрадиционных финансовых инструментов, которые вносят свой вклад в уровень финансовой нестабильности. Поэтому необходимы разнообразные индикаторы, позволяющие отображать ситуацию на рынке цифровых финансовых активов, волатильность котировок и уровень доверия инвесторов. Цель исследования — разработка и апробация на эмпирических данных обобщающего индикатора финансовой нестабильности (индекса финансового страха) на рынке цифровых финансовых активов. Новизна исследования заключается в адаптации классической модели построения индекса волатильности к рынку криптовалют. В работе использованы статистические методы сбора и обработки данных, анализа временных рядов, взвешивания, конструирования экономических показателей. Обобщены результаты современных исследований по взаимосвязи цифровизации и финансовой нестабильности. Сделан вывод, что в определенные непродолжительные периоды 2020 г. волатильность рубля к доллару была сопоставима или даже выше, чем к биткоину. Кроме того, на самом криптовалютном рынке сегодня намного меньше страха и неопределенности, чем было в конце 2018 г. Главный результат исследования — модель индекса финансового страха, основанная на применении метода расчета средневзвешенной опционной цены базисного актива и хеджирования ценовых рисков. Тестирование модели осуществлено по данным о заявочных ценах на покупку, продажу криптовалюты на определенный момент времени. Получены оценки, свидетельствующие о нарастании нестабильности на рынке цифровых финансовых активов. Сформулированы рекомендации в отношении пороговых значений индекса, по которым можно определить уровень страха инвесторов

Antiferromagnetic Bloch line driven by spin current as room-temperature analog of a fluxon in a long Josephson junction

Antiferromagnets (AFMs) are promising materials for future high-frequency field-free spintronic applications. Self-localized spin structures can enhance their capabilities and introduce new functionalities to AFM-based devices. Here we consider a domain wall (DW), a topological soliton that bridges a connection between two ground states, similar to a Josephson junction (JJ) link between two superconductors. We demonstrate the similarities between DWs in bi-axial AFM with easy-axis primary anisotropy, driven by a spin current, and long Josephson junctions (LJJs). We found that the Bloch line (BL) in DWs resembles the fluxon state of JJs, creating a close analogy between the two systems. We propose a scheme that allows us to create, move, read, and delete such BLs. This transmission line operates at room temperature and can be dynamically reconfigured in contrast to superconductors. Results of a developed model were confirmed by micromagnetic simulations for Cr$_2$O$_3$ and DyFeO$_3$, i.e., correspondingly with weak and strong in-plane anisotropy. Overall, the proposed scheme has significant potential for use in magnetic memory and logic devices.Comment: 8 pages, 5 figures; Published in Physical Review Applie

Разработка комбинированной системы отопления жилых домов и коммунальных объектов в сельской местности

В статье рассмотрена проблема создания комбинированной системы отопления жилых домов и коммунальных объектов в сельской местности, альтернативной системе отопления при использовании природного газа. Проведен поиск возможных вариантов источников энергии, разработана методика оптимизации режима работы комбинированной системы отопления. Для этого определено необходимое количество энергии и составлен алгоритм работы системы автоматизации

Spin-Hall nanooscillator based on an antiferromagnetic domain wall

We propose here a high-frequency spin-Hall nano-oscillator based on a simple magnetic texture, such as a domain wall, located in an antiferromagnet with easy-axis anisotropy type. We show that the spin current, polarized along the anisotropy axis, excites a conical precession of the N\'eel vector in such a domain wall, which allows obtaining a robust ac output signal, -- contrary to the planar precession in an uniform uniaxial antiferromagnet, where ac output is hard to achieve. The frequency of the auto-oscillations is easily tunable by the applied current up to the THz range, and the threshold current vanishes for pure uniaxial antiferromagnet. By micro-magnetic simulations, we demonstrate that the pinning of the domain wall is crucial for the oscillator design, which can be achieved in nano-constriction layout of the free layer.Comment: 7 pages, 5 figures. Brief explanation of the dynamics near the threshold is added at P.