NMR and LDA evidence for spiral magnetic order in the chain cuprate LiCu2O2

We report on {6,7}Li nuclear magnetic resonance measurements of the spin-chain compound LiCu2O2 in the paramagnetic and magnetically ordered states. Below T about 24 K the NMR lineshape presents a clear signature of incommensurate (IC) static modulation of the local magnetic field consistent with an IC spiral modulation of the magnetic moments. {7}Li NMR reveals strong phason-like dynamical fluctuations extending well below 24 K. We hypothesize that a series of phase transitions at 24.2, 22.5, and 9 K reflects a "Devil's staircase" type behavior generic for IC systems. LDA based calculations of exchange integrals reveal a large in-chain frustration leading to a magnetical spiral.Comment: 4 pages, 4 figure

Language training courses as a form of interaction between the university and business

Today, universities are quite actively establishing various forms of interaction with business, including in the field of establishing language training courses within the framework of education transfer. Here the author presents a unique experience of business interaction in the person of the Moscow Law firm and the Center for Innovative Educational and Language Strategies of the Department of English and Professional Communication of the Financial University under the Government of the Russian Federation. This research aims to study the experience of designing and implementing online language training courses «English for lawyers» for lawyers practicing international law. As it is an on-going project, the author presents the first results of the study (May – June 2023). The development of educational tracks of the course determined the reference to the ideas of personality oriented and CLIL approaches. When verifying the content of education, the author relied on the initial language proficiency level of the students and on the author’s experience in teaching Legal English, in addition, on author’s developments, materials from authentic textbooks, legal websites and newspapers, court archives available on court websites, etc. The task set by the client – the development of communication skills in the field of Legal English – largely determined the choice of teaching methods. Here the author provides parts of classes based on: case method, business and role-playing games, elements of an inverted class, etc. The obtained primary results not only testify to the effectiveness of the work done in the course of interaction between the university and business, but also allow us to foresee promising directions in the given direction, for instance: the opening of new and promising areas of training of bachelor and master students that meet the latest trends in labour market development, etc

General Relativistic Effect of Gravitomagnetic Charge on Pulsar Magnetosphere and Particle Acceleration in a Polar Cap

We study magnetospheric structure surrounding rotating magnetized neutron star with nonvanishing NUT (Newman-Tamburino-Unti) parameter. For the simplicity of calculations Goldreich-Julian charge density is analyzed for the aligned neutron star with zero inclination between magnetic field, gravitomagnetic field and rotation axis. From the system of Maxwell equations in spacetime of slowly rotating NUT star, second-order differential equation for electrostatic potential is derived. Analytical solution of this equation indicates the general relativistic modification of an accelerating electric field and charge density along the open field lines by the gravitomagnetic charge. The implication of this effect to the magnetospheric energy loss problem is underlined. In the second part of the paper we derive the equations of motion of test particles in magnetosphere of slowly rotating NUT star. Then we analyze particle motion in the polar cap and show that NUT parameter can significantly change conditions for particle acceleration.Comment: 21 pages, 6 figures, accepted for publication in Ap

Variations in geoacoustic emissions in a deep borehole and its correlation with seismicity

Continuous geoacoustic emission (GAE) measurements were acquired using a three-component geophone placed in a borehole at a depth of near 1000 m at Petropavlovsk-Kamchatsky starting in August 2000. Using geophones consisting of magneto-elastic crystal ferromagnetic sensors, and installed at such a depth allows measurement of natural geoacoustic background with signal amplitude less than 1×10-4 m/s3 in frequency band from 3 to 1500 Hz. According to the data from a 4-year survey period the characteristics of diurnal geoacoustic variations change before every earthquake with MLH≥ 5.0 that occurs at a distance of less than 300 km from the observation point or before each earthquake with MLH≥5.5 occurring at distance R≤550 km from the observation point. The changes in GAE regime correlate with the strongest earthquakes that occurred during survey period. Measurements of the natural electromagnetic field of the Earth were carried out simultaneously with the help of an underground electric antenna. The behavior of GAE in aseismic periods appears to be related to the effect of diurnal variations of the natural electromagnetic field

Correction of artificial jumps in the historical geomagnetic measurements of Coimbra Observatory, Portugal

The Coimbra Magnetic Observatory (International Association of Geomagnetism and Aeronomy code COI) in Portugal has a long history of observation of the geomagnetic field, spanning almost 150 yr since the first geomagnetic measurements in 1866. These long instrumental geomagnetic records provide very important information about variability of geomagnetic elements and indices, their trends and cycles, and can be used to improve our knowledge on the sources that drive variations of the geomagnetic field: liquid core dynamics (internal) and solar forcing (external). <br><br> However, during the long life of the Coimbra Observatory, some inevitable changes in station location, instrument's park and electromagnetic environment have taken place. These changes affected the quality of the data collected at COI causing breaks and jumps in the series of geomagnetic field components and local K index. Clearly, these inhomogeneities, typically shift-like (step-like) or trend-like, have to be corrected or, at least, minimized in order for the data to be used in scientific studies or to be submitted to international databases. <br><br> In this study, the series of local K index and declination of the geomagnetic field are analysed: the former because it allows direct application of standard homogenization methods and the latter because it is the longest continuous series produced at COI. For the homogenization, visual and statistical tests (e.g. standard normal homogeneity test) have been applied directly to the local geomagnetic K index series (from 1951 to 2012). The homogenization of the monthly averages of declination (from 1867 to 2012) has been done using visual analysis and statistical tests applied to the time series of the first differences of declination values, as an approximation to the first time derivative. This allowed not only estimating the level of inhomogeneity of the studied series but also detecting the highly probable homogeneity break points. These points have been cross-checked with the metadata, and the COI series have been compared with reference series from the nearest geomagnetic stations and, in the case of declination series, from the recent geomagnetic field model COV-OBS to set up the required correction factors. As a result, the homogenized series measured in COI are considered to be essentially free of artificial shifts starting from the second half of the 20th century, and ready to be used by the scientific community

The Indicative Potential of the Forest-Tundra Landscape Component

In order to expand the possibilities of soil-cover remote monitoring and improve prognostic models of active-layer depth dynamics in connection with global climatic changes, the verification of correspondence between plant and soil components of subarctic landscapes is necessary. This is most relevant for the forest-tundra zone,where the variety and mosaicity of soils and vegetation is great due to its ecotonic position. The purpose of this work was to study the relationship of vegetation with the characteristics of cryogenic soils and the dynamics of the active layer in forest-tundra landscapes. Data were obtained during monitoring studies at key sites in diverse landscapes of forest-tundra in the vicinity of Labytnangi. It was revealed that the thickness of the organogenic horizons, as well as the value of the moss phytomass, determine the active-layer thickness. A close connection with relief and soils allows the use of vegetation as an indicator of the soil texture and the depth of active-layer occurrence and features. Keywords: plant communities, cryogenic soils, active layer, landscape, forest-tundra, Western Siberi

Changes of the body functions during long-term hypokinesia

Prolonged hypokinesis (100-170 days) studied in 2000 rats kept in cages limiting their mobility provoked considerable changes in the gaseous and energetic metabolism: an elevation of the total gaseous metabolism and of the rate of O2 requirement by the muscles (in the late periods of hypokinesis) and a change in the intensity of tissue respiration of the liver and myocardium. There also proved to be a reduction in the level of phosphorylation and separation of oxidative phosphorylation in the myocardium, liver, and partially in the skeletal muscle. Prolonged hypokinesia led to changes in tissue metabolism: a disturbance of development of the animals, a marked delay and an increase in the weight of the organism and the muscular system, and disturbances of the mineral and protein metabolism. Prolonged hypokinesis also lead to exhaustion of the hypothalamus-hypophysis-adrenal cortex system

External Electromagnetic Fields of a Slowly Rotating Magnetized Star with Gravitomagnetic Charge

We study Maxwell equations in the external background spacetime of a slowly rotating magnetized NUT star and find analytical solutions for the exterior electric fields after separating the equations of electric field into angular and radial parts in the lowest order approximation. The star is considered isolated and in vacuum, with dipolar magnetic field aligned with the axis of rotation. The contribution to the external electric field of star from the NUT charge is considered in detail.Comment: 6 pages, 2 figures, accepted for publication in Astrophysics and Space Scienc

ПОБУДОВА МОДЕЛІ МІНІМІЗАЦІЇ ФІНАНСОВИХ РИЗИКІВ МАШИНОБУДІВНИХ ПІДПРИЄМСТВ

The article is based on a financial condition indicators system, which assesses the financial risk of the enterprise, and their grouping according to the nature of the impact on the enterprise financial position. The following financial risks groups have been identified: the inappropriate capital structure, inefficient financial activity, liquidity decline, ineffective operating activities, the imbalances in cash flows and ineffective investment activities risks. Each group of indicators is selected by the "center of gravity"one representative method to construct a model for assessing the financial risk in the enterprise level. It is determined that representative indicators in identifying the financial risk in an enterprise level are: coefficient of autonomy, coefficient of turnover of capital, absolute liquidity ratio, return on sales, net cash flow ratio, total return on investment.At the next stage of constructing a model for enterprise financial risks minimizing using expert method, representative indicators are measured according to their informativity for assessing financial risk at the enterprise. Taking into account the indicators significance, a machine-building enterprises assessment financial risk model was constructed on the basis of the enterprise financial risk level indicators-representatives additive convolution with their significance weight coefficients correction.The functional dependencies between the indicators are determined given the direct and inverse nature of the link between the indicators that characterize the machine-building enterprises financial risk, using correlation-regression analysis. An optimization model for machine-building enterprises financial risks minimizing was built on the principle of limiting financial risks. Optimizing the model means getting the maximum integral index value of the financial risk neutralization level. To this end, the Kuhn-Tucker theorem is used. As a result of model optimization it was revealed that from the point of view the financial risks at machine-building enterprises level minimizing, the optimum values of financial indicators are: for the coefficient of autonomy — 0.41; for the capital turnover coefficient — 31,0; for the coefficient of absolute liquidity — 0,45; for a profitability ratio of sales — 0,29; for the coefficient of sufficiency of net cash flow — 0,60; for the coefficient of total return on investment — 0,28. The established norms of financial indicators provide financial risk minimization at machine-building enterprises.Построены модель оценки уровня финансовых рисков на машиностроительных предприятиях, а также модель минимизации финансовых рисков машиностроительных предприятий. Определены оптимальные значения финансовых нормативов: коэффициента автономии, оборачиваемости капитала, абсолютной ликвидности, рентабельности продаж, достаточности чистого денежного потока, совокупной рентабельности инвестиций, соблюдение которых снизит уровень финансовых рисков на предприятиях, обеспечит эффективность их деятельности, финансовую устойчивость, ликвидность и платежеспособность.Побудовано систему показників фінансового стану, за якими оцінюється фінансовий ризик підприємства, та здійснено їхнє групування за характером впливу на фінансовий стан підприємства. Виділено такі групи фінансових ризиків: ризик нераціональної структури капіталу, ризик неефективної фінансової діяльності, ризик зниження ліквідності, ризик неефективної операційної діяльності, ризик незбалансованості грошових потоків і ризик неефективної інвестиційної діяльності. Для побудови моделі оцінки рівня фінансового ризику на підприємстві з кожної групи показників обрано по одному репрезентативному методом «центру ваг». Визначено, що репрезентативними показниками при ідентифікації рівня фінансового ризику на підприємстві є: коефіцієнт автономії, коефіцієнт оборотності капіталу, коефіцієнт абсолютної ліквідності, коефіцієнт рентабельності продажів, коефіцієнт достатності чистого грошового потоку, сукупна рентабельність інвестицій.На наступному етапі побудови моделі мінімізації фінансових ризиків підприємства з використанням експертного методу проранговано репрезентативні показники за їхнього інформативністю для оцінки фінансового ризику на підприємстві. З урахуванням значимості показників побудовано модель оцінки фінансових ризиків машинобудівних підприємств на основі адитивної згортки показників-репрезентантів рівня фінансового ризику підприємства з коригуванням на вагові коефіцієнти їхньої значимості.Ураховуючи прямий і обернений характер зв’язку між показниками, що характеризують рівень фінансового ризику машинобудівних підприємств, з використанням кореляційно-регресійного аналізу, визначено функціональні залежності між показниками. Побудовано оптимізаційну модель мінімізації фінансових ризиків машинобудівних підприємств, в основу якої закладено принцип лімітування фінансових ризиків. Оптимізація моделі означає отримання максимального значення інтегрального показника рівня нейтралізації фінансового ризику. Для цього використано теорему Куна — Таккера. У результаті оптимізації моделі виявлено, що з позиції мінімізації рівня фінансових ризиків на машинобудівних підприємствах оптимальними значеннями фінансових показників є: для коефіцієнта автономії — 0,41; для коефіцієнта оборотності капіталу — 31,0; для коефіцієнта абсолютної ліквідності — 0,45; для коефіцієнта рентабельності продажів — 0,29; для коефіцієнта достатності чистого грошового потоку — 0,60; для коефіцієнта сукупної рентабельності інвестицій — 0,28. Установлені нормативи фінансових показників забезпечують мінімізацію фінансового ризику на машинобудівних підприємствах