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The rapid growth of public debt in developing countries in recent years and the increasing risks associated with this process emphasize the importance of research in this area. The article examines one of the key aspects of public debt management — the structure of creditors’ debt portfolio. The object of the study is the public debt of four countries of Central Asia and three countries of the South Caucasus. The states of this region are important foreign economic partners of Russia, their contribution to mutual trade and realization of joint projects is growing. Their role in the global and regional economy is also expanding, including participation in major transport and logistics projects designed to increase the connectivity of Eurasia. The study is based on the data of international organizations on the total volume of public debt, debt to individual external creditors and the dynamics of macroeconomic indicators. The article examines changes in the structure of the main groups of creditors for each country over three long-term periods and analyzes similarities and differences in the observed structural shifts. It also decomposes the indicator of public debt dynamics and estimates the contribution of the economic growth factor and the effects of changes in countries’ debt to certain groups of creditors. The study identified the following key trends in public debt structural changes: 1) the declining role of bilateral loans from developed and developing countries since the 2000s; 2) the continued strong influence of debt raised from international financial organizations and development banks in most countries throughout the period under study; 3) in a number of countries, a gradual increase in market sources of debt financing (domestic and Eurobonds); the increasing role of loans from China — in the Kyrgyz Republic and the Republic of Tajikistan, etc. The study identifies reasons for these structural changes, and concludes with a discussion of the risks associated with the observed shifts in the structure of public debt.

Cathode materials with mixed ion-electron conductivity (MIEC) are necessary for the development of low or intermediate temperature solid oxide fuel cells. Perovskite and perovskite-related materials are promising candidates on this role. In the review the conductivity and the thermal expansion of materials with various types of perovskite-related structures such as pure perovskite, double perovskite, brownmillerite and Ruddlesden-Popper phases have been compared. And the literature data on the values of the electronic and ionic conductivities, the oxygen diffusion coefficient, and the thermal expansion coefficient of various compositions have been collected. It was shown that the disordered cubic perovskites possess the higher electronic conductivity whereas the layered perovskites and materials with the Ruddlesden-Popper structure have higher ionic conductivity and lower value of thermal expansion.

The article highlights the issues of creating with the necessary accuracy a planned control on the industrial site of the engineering structures under construction using satellite technologies and total stations. Depending on the design features of the engineering structures under construction, as well as the technological scheme for the installation of building constructions and industrial equipment, various schemes for creating such control are considered, based on the application of the inverse linear-angular notch. Errors in the source data are one of the main errors that affect the accuracy of geodetic constructions, including the solution of the inverse linear-angular notch. When creating a geodetic network in several stages, the errors of the initial data of the first stage affect the values of the root-mean-square errors (RMS) of determining the position of the second stage points, the errors of which affect the value of the RMS of the position of the third stage points, etc. The reason for their occurrence is the errors of geodetic measurements that occur at each stage of control creating, as well as the stability violation of the points during the production of excavation, construction and installation works. When determining the coordinates of a separate project point at the stage of its removal in-situ by a total station, the entire network is not equalized in the vast majority of cases, and the coordinates of the starting points to which the total station is oriented are considered error-free. As a result, the RMS determination of the points coordinates of the control network or the removal of the design points of the elements of building structures and equipment will also be considered satisfying the requirements, i.e. the measurement accuracy will be artificially overestimated and will not correspond to the actual one obtained. This is due to the fact that the accumulation of errors in the initial data is not taken into account when the number of steps (stages) of control creating increases. The purpose of this work is to analyze the influence of measurement errors and initial data when creating a geodetic control on an industrial site by several stages of its construction based on inverse linear-angular notches and a priori estimation of the accuracy of the determined points position.

Objective: assessment of the resistance of the body of athletes-divers to the hyperbaric oxygen toxicity on indicators of the heart rate variability (HRV). Materials and methods. The study involved 38 healthy athletes-divers aged 23 to 32 years. Before the session of hyperbaric oxygenation (HBO), the test subject was measured the blood pressure and pulse by the method of oscillometry while he was sitting at rest, after which a five-minute recording of HRV in sitting position at rest was made. After that, the two test subjects were placed together, sitting with a physician in a pressure (decompression) chamber, where an absolute pressure of 0.25 MPa was created. The test subjects were given 100 % medical oxygen to breathe, their pulse and blood pressure were measured every 15 minutes, and their cardiac output (CO) was calculated by the Starr formula. When there was an increasing tendency of the CO, and also after 75 minutes of oxygen breathing, the test subjects were taken out of the pressure chamber. Immediately after leaving the pressure chamber, the HRV of the test subjects was recorded. According to the results of measurement of hemodynamic parameters, the test subjects were divided into 3 groups. The first group — unstable, whose CO began to increase in the first 45 minutes of HBO, the second group included those whose CO began to increase from 46 to 75 minutes, the third group included test subjects whose CO did not increase. Results. HRV analysis showed the most significant reliable (p < 0.001) VLF spectrum power (ms2) and relative VLF power (%), as well as Alpha 2 after HBO in the first group of test subjects (unstable) compared to the initial parameters and other groups, which reflects the activation of the sympathetic nervous system and suprasegmental structures of the brain. The essence of changes in the HRV time domain indicators (decrease in SNS index, pNN50 (%), PNS index) confirms the presence of pronounced sympathicotonia in the first group. Conclusions: the three most significant metrics (VLF (ms2), VLF (%) and Alpha 2) were determined with high confidence (p < 0.001), which have a moderate negative correlation (–0.70 < r < –0.30) with the level of divers’ resistance to the to the hyperbaric oxygen toxicity. Observations of athletes with high stability showed that they were characterized by changes in hemodynamics of the vagotonic type, while unstable ones were characterized by the sympathicotonic type of regulation. Evaluation of the results showed amoderate correlation between HRV and symptom of oxygen toxicity on divers and is recommended for a reliable (p < 0.05) diagnosis.

Objective: to improve the methodology of timely functional body’s reserves assessment, to reduce the probability of an infectious disease in divers during the training and competition period in the countries with severe climate. Materials and methods: We performed the mathematical and statistical analysis of the examination data and the frequency of infectious diseases in 2018-2019 in 47 male divers (mean age 30,5±3,56). Th e study involved volumetric compression oscillometry (VKO) and heart rate variability (HRV). Results: in the volumetric compression oscillometry and heart rate variability analysis, we determined the most signifi cant (p

Relevance of the researchis caused by the fact that currently in the Russian Federation, for servicing mining and development of minerals, it is necessary to perform survey and geodetic works, by the results of which arrays of geospatial data are formed.They are the basis for the design and arrangement of oil and gas fields and are the source information for three-dimensional modeling of the earth's surface, geological structures of deposits and infrastructure of pipeline systems. Besides, geospatial data is necessary for preparation of documents for state cadastral registration and registration of land use rights. Based on this, the article sets scientific and technical task: analyze the possibilities of using various methods of providing geospatial information GIS pipeline systems with data for 3D modeling of the studied fields and pipelines. Corporate GIS is filled with data on the state of pipeline transport, using information from space survey systems with high and medium spatial resolution, as well as shooting materials from unmanned aerial vehicles and aerial laser scanning. Monitoring of pipeline systems is carried out as well using ground-based geodetic survey data. One of most common types of modern geodetic equipment is high-precision and accurate electronic total stations that allow you obtain geospatial information on terrain and anthropogenic objects bothin terms of plan and height. The height component is determined as result of performing trigonometric leveling. The use of the trigonometric leveling method is especially relevant when working in rough terrain and adverse conditions, in particular in regions of the Extreme North. The aim of the research is toanalyze the possibilities of using various methods of providing geospatial information for GIS pipeline systems: satellite surveys with different spatial resolutions, unmanned aerial vehicles and aerial laser scanningdata, trigonometric leveling of classes III and IV with the use of high-precision electronic total stations in the formation of geospatial data arrays of main pipeline monitoring systems. Methods: decoding of aerospace images, experimental research in field with space survey materials, unmanned aerial vehicles and aerial laser scanningdata, use of high-precision levels and electronic total stations for trigonometric leveling, geoinformation technologies Results. Quality of geospatial information for GIS monitoring of pipeline systems was evaluated. The work shown that the data from remote sensing of the Earth with different spatial resolutions, unmanned aerial vehicles and aerial laser scanning allow forming arrays of geospatial data necessary for services operating pipeline systems, providing planned linking with sufficient accuracy; when creating high-altitude geodetic justification, when accuracy needs be increased to class III and IV, instead of time-consuming geometric leveling, it is advisable to supplement arrays with information, obtained by trigonometric leveling using high-precision electronic tacheometers.

We report measurements of π+ and π0 meson photoproduction from longitudinally spin-polarised protons by an energy tagged (0.73-2.3 GeV) and linearly polarised photon beam. A close to complete solid angle coverage for the reaction products was provided by the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The double-polarisation observable G is extracted from Maximum Likelihood fits to the data, enabling the first accurate determination for the reaction γ→p→→π+n, while also significantly extending the kinematic coverage for γ→p→→π0p. This large data set provides an important constraint on the properties and spectrum of excited nucleon states decaying to Nπ in the mass range from 1.4 to 2.2 GeV, as well as for background (non-resonant) photoproduction processes. The considerable improvement achieved in the description of the observable G within the SAID and Bonn-Gatchina approaches after implementation of our data, illustrates that the partial-wave analyses now significantly extend the knowledge on Nπ photoproduction amplitudes at W>1.8 GeV. A partial-wave analysis using the new high-precision data set has a large impact on the extracted properties of high-spin nucleon excited states.

Over the last two decades, the scientific community and industry have made huge efforts to develop environmental protection technologies. In particular, the scarcity of drinking water has prompted the investigation of several physico-chemical treatments, and synergistic effects have been observed in hyphenated techniques. Herein, we report the first example of water treatment under simultaneous hydrodynamic cavitation and plasma discharge with the intense generation of radicals, UV light, shock waves and charged particles. This highly reactive environment is well suited to the bulk treatment of polluted water (i.e. E. coli disinfection and organic pollutant degradation). We have developed a new prototype and have efficiently applied this hybrid technology to water disinfection and the complete degradation of methanol in water with the aim of demonstrating its scalability. We have analyzed the mechanisms of water disinfection under the abovementioned conditions and verified them by measuring cavitation noise spectra and plasma emission spectra. We have also used the degradation of textile dyes and methanol solutions as an indicator for the formation of radicals.

The polarization observables T,E,P,H, and G in photoproduction of η mesons off protons are measured for photon energies from threshold to W=2400 MeV (T), 2280 MeV (E), 1620 MeV (P,H), or 1820 MeV (G), covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, JüBo, and BnGa partial-wave analyses. A refit within the BnGa approach including further data yields precise branching ratios for the Nη decay of nucleon resonances. A Nη-branching ratio of 0.33±0.04 for N(1650)1/2− is found, which reduces the large and controversially discussed Nη-branching ratio difference of the two lowest mass JP=1/2−-resonances significantly. Keywords: Baryon spectroscopy, Meson photoproduction, Polarization observables

Solid oxide fuel cells (SOFC) are promising, environmentally friendly energy sources. Many works are devoted to the study of materials, individual aspects of SOFC operation, and the development of devices based on them. However, there is no work covering the entire spectrum of SOFC concepts and designs. In the present review, an attempt is made to collect and structure all types of SOFC that exist today. Structural features of each type of SOFC have been described, and their advantages and disadvantages have been identified. A comparison of the designs showed that among the well-studied dual-chamber SOFC with oxygen-ion conducting electrolyte, the anode-supported design is the most suitable for operation at temperatures below 800 °C. Other SOFC types that are promising for low-temperature operation are SOFC with proton-conducting electrolyte and electrolyte-free fuel cells. However, these recently developed technologies are still far from commercialization and require further research and development.

Solvent-free aerosol jet printing has been investigated for fabricating metallic and semiconductor (gas-sensitive) microstructures based on copper nanoparticles on alumina, borosilicate glass, and silicon substrates. The synthesis of nanoparticles was carried out using a spark discharge directly in the printing process without the stage of preparing nano-ink. Printed lines with a width of 100–150 µm and a height of 5–7 µm were formed from submicron agglomerates consisting of primary nanoparticles 10.8 ± 4.9 nm in size with an amorphous oxide shell. The electrical resistivity, surface morphology, and shrinkage of printed lines were investigated depending on the reduction sintering temperature. Sintering of copper oxides of nanoparticles began at a temperature of 450 °C in a hydrogen atmosphere with shrinkage at the level of 45–60%. Moreover, aerosol heat treatment was used to obtain highly conductive lines by increasing the packing density of deposited nanoparticles, providing in-situ transformation of submicron agglomerates into spherical nanoparticles with a size of 20–50 nm. Copper lines of spherical nanoparticles demonstrated excellent resistivity at 5 μΩ·cm, about three times higher than that of bulk copper. In turn, semiconductor microstructures based on unsintered agglomerates of oxidized copper have a fairly high sensitivity to NH3 and CO. Values of response of the sensor based on non-sintered oxidized copper nanoparticles to ammonia and carbon monoxide concentration of 40 ppm were about 20% and 80%, respectively.

The article deals with the problem of identifying specific com­petencies of Master in dentistry. The results of the analysis of domestic and foreign scientific literature, legal documents regulating the implementation of competence-based approach in higher medical education is presented, international experience in the modernization of higher education, including medical, on the basis of changes in the educational paradigm on competence approach is studied. In the process of identifying set of special competences of Master of dentistry, the main ideas of the existing professional Standards in Dentistry were used. A worked out set of special competences reflects peculiarities of the profession in accordance with the algorithm, aimed to help dental patient in a vicious circle from disease prevention to rehabilitation after diseases, the latter includes legal, methodical, social and managerial aspects of the professional activities of a dentist.

The paper shows possibility to use Paris-Erdogan equation for simulation of fatigue crack growth under random loading. In the considered equation effective stress intensity factor range was introduced. The introduced methodology for crack growth simulation is based on the concept of a “basic” random loading. The discussed methodology included consideration of overloads influence on the fatigue crack growth. The theoretical models are based on the experimental researches of fatigue crack growth under random loading that have realized during specimens fatigue tests of two Al-based alloys (D16АТ - the same as 2024-T3, and В95АТВ - 7075-T6). In all cases the random loading has been considered as Gaussian processes of cyclic loading with introduced and discussed parameters of the investigated processes.

The paper shows the possibility of using Paris-Erdogan equation for simulation fatigue crack growth under random loading. The considered equation has introduced the effective stress intensity factor range. The introduced methodology for crack growth simulation is based on the concept of a “basic” random loading. The discussed methodology included consideration of overloads influence on the fatigue crack growth. The theoretical model is based on the experimental researches of fatigue crack growth under random loading that have been realized during specimens fatigue tests of two Al-based alloys (D16chАТ - the same as 2024-T3, and В95АТВ - 7075-T6). In the tests the specimens of a center cracked panel were used. In all cases the random loading has been considered as Gaussian processes of cyclic loading with introduced and discussed parameters of investigated processes. As a result of investigations the model for estimation crack growth period in the different random of irregular cyclic loads was introduced.

Direct transformation of chemical energy of fuel to energy with use Solid Oxide Fuel Cells (SOFC) is perspective technology of highly effective, non-polluting power. Individual fuel cells are multilayered heterostructure on a basis ionic conductivity the solid electrolyte, consisting of materials with various properties and type of conductivity. It the material of electrolyte should possess high only ionic conductivity and to be gastight materials of electrodes should have high electronic and ionic conductivity, catalalyic activity and possess sufficient porosity for delivery and to tap of reagents on three-phase, where are basic reactions to not create diffuses difficulties and to not limit course of a current.

The first measurements of the beam-target-helicity-asymmetries E and G in the photoproduction of ω-mesons off protons at the CBELSA/TAPS experiment are reported. E (G) was measured using circularly (linearly) polarised photons and a longitudinally polarised target. E was measured over the photon energy range from close to threshold (Eγ=1108 MeV) to Eγ=2300 MeV and G at a single energy interval of 1108

Data on the polarization observables T, P, and H for the reaction γp→pπ0 are reported. Compared to earlier data from other experiments, our data are more precise and extend the covered range in energy and angle substantially. The results were extracted from azimuthal asymmetries measured using a transversely polarized target and linearly polarized photons. The data were taken at the Bonn electron stretcher accelerator ELSA with the CBELSA/TAPS detector. Within the Bonn-Gatchina partial wave analysis, the new polarization data lead to a significant narrowing of the error band for the multipoles for neutral-pion photoproduction.