Home – Home – Jornals – Avtometriya 2022 number 5

The Kamchatka Peninsula is one of the most tectonically active regions in the world, where intensive and diverse modern volcanic activity takes place. In the recent decade, a substantial progress in the investigation of deep structures beneath Kamchatka has been achieved owing to numerous tomography studies based on seismological data provided by permanent stations and temporary networks deployed in some key areas. The goal of this review is summarizing and systematizing dozens of separate multiscale geophysical studies in Kamchatka and constructing an integral model of volcano-feeding systems. An important part of this review contains the description of results of various seismic studies related to the Klyuchevskoy group volcanoes, which can now be considered one of the best studied volcanic areas in the world. The results of the regional-scale seismic tomography reveal the existence of the Pacific slab window, which determines the particular activity of the Klyuchevskoy group volcanoes. Middle-scale tomography studies have found traces of an ascending hot mantle flow that passes through the slab window, reaches the bottom of the crust below Shiveluch Volcano and then propagates laterally toward the Klyuchevskoy group. Seismic models of the entire crust in the area of the Klyuchevskoy group were used to identify different mechanisms of magmatic feeding of three most active volcanoes: Klyuchevskoy, Bezymianny, and Tolbachik. The data of local networks deployed on several volcanoes of Kamchatka were used to image the magma sources in the upper crust, which are directly responsible for the current eruption activity. The comparison of the results for the Kamchatkan volcanoes with tomography models of several other volcanoes of the world allowed determining some common features and differences in feeding active magmatic systems.

Along the submeridional seismic and magnetotelluric profiles, crossing the junction zone of the Kyrgyz Range and the Chu basin of the Northern Tien Shan, the models of density, Poisson’s ratio, elastic modulus, silica content, temperature, and porosity have been constructed. Based on the complex analysis of the constructed profiles of physicomechanical rock properties, a geological-geophysical lens model has been constructed. This model addresses the sources of geophysical anomalies (found at the northern border of the lens) and possible mechanisms of the lens formation.

Detection of common quasiperiodicities in the paleointensity behavior and lengths of polarity intervals of the Earth’s magnetic field was carried out. The paleointensity data were analyzed in the 170 Ma-present day interval. Behavior of the lengths of geomagnetic polarity intervals was investigated within the interval spanning the entire Phanerozoic (540 Ma-present age). It was found that the spectrum of the main paleointensity variations and polarity interval lengths is discrete and includes quasiperiodic variations with characteristic times of 15, 8, 5, and 3 Ma. The characteristic times of these quasiperiodic variations in the geomagnetic field at the beginning and end of the Phanerozoic differed not more than 10%. The spectral density of quasiperiodic changes in the geomagnetic field changed cyclically over geological time. The connection between the behavior of the amplitudes of paleointensity variations, the lengths of geomagnetic polarity intervals, and their spectral density is shown. The spectral density of quasiperiodic paleointensity variations (geomagnetic activity) was relatively high in the 150-40 Ma interval (Cretaceous-early Paleogene). At this time, the amplitudes of paleointensity variations and the lengths of geomagnetic polarity intervals increased. Within the intervals spanning 170-150 Ma and 30 Ma-present age, the quasiperiodic variations of paleointensity were barely expressed against its background noise variations, while the amplitudes of paleointensity variations and the lengths of polarity intervals were decreasing. Alternations of the time intervals in which paleointensity variations acquired either a quasiperiodic or noise character took place during the evolution of the geomagnetic field.

The self-excited oscillator describing high-frequency excitations of a drillstring with high amplitudes of torsional oscillations has been presented. The self-excited oscillator is characterized by discrete degrees of freedom. Fundamentally, the work of the self-excited oscillator is based on the idea of the maximum cutting force during the destruction of rock by PDC bits and the results of laboratory studies by M.I. Vorozhtsov, K.I. Borisov, G.P. Cherepanov. The differential equations of the non-autonomous self-excited oscillator are based on the results of laboratory studies. A typical dynamic mode of the self-excited oscillator operation has been presented. The results have been compared with experimental data.

In the present paper we demonstrate that most sulfides of the studied deposits of the Archean Sumozero-Kenozero greenstone belt within the Karelian Craton on the Fennoscandian Shield have nonzero Δ³³S values. This indicates that proportions of seawater sulfate and elemental sulfur in Mecoarchean included into the ores and resulting from UV photolysis, are different. Our results show that systematics of sulfur isotopes of sulfides generally reflects the mixing of mass-independently fractionated sulfur reservoirs with positive and negative Δ³³S values. Pyrite is depleted in ³⁴S isotope, which was interpreted as evidence for microbial sulfate reduction. Variations in the positive Δ³³S anomalies of the Leksa deposit and the general tendency for Δ³³S sulfide content to increase with stratigraphic levels in certain boreholes most likely reflect the change in temperature and the fluid mixing throughout the life of the hydrothermal system. The presence of sulfides with strongly negative Δ³³S anomalies suggests that atmospheric sulfur and seawater sulfate, rather than volcanic sulfur, were the prevailing source for mineral systems of the studied deposits. The presented data require the Mesoarchean seawater to contain sulfates at least locally.

Analysis shows that the occurrences of ore gold of different formational types and ages widespread in the Republic of Tyva are related to the intricate and long geologic history of this region. The Tyva region is of polycyclic development; in the period from the Precambrian to the Cenozoic, there were stages of subduction, accretion-collision, and rifting processes accompanied by volcanism of different types and a wide manifestation of granitoid magmatism. Gold metallogeny was discretely developed throughout the geologic history of the region and was most widely manifested at the island arc stage (570-510 Ma), in connection with the formation of gold-bearing pyrite-polymetallic deposits. The late Cambrian-Ordovician period of granitoid magmatism was also productive for gold mineralization: It was marked by the formation of porphyry Au-Cu-Mo deposits, proper gold deposits, and gold-skarn, gold-quartz, and gold-beresite ore occurrences. Several gold-bearing clusters confined to different structure-formational zones are distinguished in the Tuva area. To date, gold contents of commercial interest have been identified in the Tardanskoe gold deposit with Au reserves of 7371.8 kg, in the gold-bearing Kyzyl-Tashtyg pyrite-polymetallic deposit with estimated Au reserves of 15.08 tons and Ag reserves of ~700 tons, and in the gold-bearing Ak-Sug porphyry Cu-Mo deposit with C₂ gold reserves of 83 tons and silver reserves of 368 tons. In the course of prospecting and revision performed at many gold ore clusters in recent years, additional information about the high endogenous-gold potential of the Republic of Tyva has been obtained. There are a number of objects promising for commercial reserves of endogenous gold, such as The Kara-Bel’dir gold ore cluster with C₁ and C₂ gold reserves of 22.8 tons, the Aldan-Maadyr gold ore cluster with predicted P₂ gold resources of 38 tons and Р₃ gold resources of 80 tons, the Eiligkhem ore cluster with predicted P₃ gold resources of 36 tons, the Kyzyk-Chadr ore cluster with predicted Р₁ + Р₂ gold resources of 39.7 tons and silver resources of 198 tons at the Kyzyk-Chadr deposit, and the East Tannu-Ola ore district with Au resources of 68.3 tons. Thus, the intricate geologic development of the Tyva area and various geologic events, including large-scale magmatic processes, led to the formation of both gold and gold-bearing deposits and ore occurrences, which give reason to anticipate revealing of large commercial reserves of endogenous gold and the development of gold mining industry in the republic.

This study describes a procedure for estimating the distribution of hydrocarbon resources by fields with different amounts of reserves and by the number of pools in each field. Such estimation is important for predicting the exploration efficiency. The procedure first uses a simulation model for generating a population of hydrocarbon pool sizes. Then, the spatial distribution of pools over a petroleum basin is modeled as a nonstationary Poisson point field. When generating a field population in the basin, each field is considered a geometric object consisting of several pools according to the principle of their mutual geometric location. The proposed model was used to estimate the two-dimensional distribution of the number of fields and the amount of resources in them by the reserve sizes and by the number of pools in each field. The proposed assessment was made for oil resources in the West Siberian petroleum province.

From the viewpoint of modern knowledge, the geological structure of the Upper Jurassic-Neocomian clinoform complex, its regional seismogeological model has been constructed, and the criteria to locate oil accumulation zones (OAZ) and specific oil-promising prospects have been identified. All these factors made it possible to provide a significant increase in oil resources.

The paper presents a new robust video watermarking method. Its main idea consists in adding temporal sinusoidal sequences to each pixel of the video signal. The two-dimensional field of their phases corresponds to the watermark image. Simple and fast algorithms for embedding and extracting watermarks are described. The results of experimental studies demonstrate the high watermark extraction quality, robustness to some attacks, including temporal desynchronization, and high visual quality of the protected video.

In a space of tree-structured object representations, the accuracy of object classification in terms of an error probability depending on the amount of processed information is studied. For a given set of objects, the lower bound to the average error probability as a function of the average mutual information between the objects and the decisions about their classes is given. Using multilevel discriminant functions in the set of object representations, a guided search algorithm for an object class-label decision is proposed, and a computational profit of the guided search relative to the exhaustive search is shown analytically. In the source datasets of face and signature objects given by the grayscale images as well as in an ensemble of these datasets, we calculate the experimental dependences of the average error probability and the average mutual information on the algorithm parameter which defines the above-mentioned computational profit. Also, for both source datasets and their ensemble, we give numerical values of the lower bounds to the error probability that allow us to estimate the redundancy of the algorithm error probability for different values of the computational profit.

The goal of registering point clouds in a 3D space is to find an orthogonal transformation that maximizes the consistent overlap of two point clouds. The most common registration method using purely geometric characteristics is the Iterative Closest Points (ICP) algorithm. The disadvantage of the classical ICP variants is the dependence on the initial location of the point clouds. Coarse registration algorithms are used to find a suitable initial registration of two clouds. In this paper, we propose a new algorithm for extracting common parts and coarse registration of point clouds.

In this paper, we propose a new two-level method for combining image segmentation maps based on minimizing the two-objective quality functional. The functional is formed as a weighted sum of the information redundancy measure and variation of information computed from the original image and the combined segmentation map. Applying such a measure, we obtain an image partition that provides a compromise between the objectives of minimizing the number of outlined informationally important segments and minimizing the information difference between the original image and the resulting partition. The proposed method improves the result of segmentation in comparison with the method for combining partitions based on the criterion of the minimum information redundancy.

The article deals with the issues of image restoration when only a part of observations subjected to additive noise regularly placed in the original image is available. In other words, the problem of restoration of a thinned image is solved (based on pilot pixels). Pixels themselves are mixed with the white Gaussian noise. To solve this problem, special modifications of nonlinear filters are synthesized based on deep doubly stochastic Gaussian models. The results obtained allow us to draw a conclusion about the effectiveness of the proposed filters in comparison with linear methods and traditional algorithms. The study shows that images can be reconstructed based on only 50% of information using a doubly stochastic model, resulting in a relative error of only 9%.

A technique for eliminating the influence of the image interpolation effect in the algorithm of estimating image spatial deformations is proposed. The technique is considered for similarity measures of images used in the synthesis of algorithms, in particular, the mean square of the inter-frame difference, the inter-frame correlation coefficient, and the Shannon mutual information. Calculated expressions for compensating the influence of bilinear and bicubic interpolation are obtained. The developed technique is also applicable to other similarity measures used in the development of algorithms for estimating spatial deformations of images, as well as any interpolations: spline, using Lagrange and Newton polynomials, power functions, etc.

The technology of constructing a recursive filter on a non-uniform grid of samples with parameter identification on test images is discussed. This filter is the IIR-filter that has a physical feasibility problem. To overcome it, a multi-step procedure is implemented. Unfortunately, identifying the best filter in terms of a given criterion does not guarantee that a recursive implementation of that filter will be stable. In the paper, for the considered iterative scheme, stability conditions are obtained. It has been experimentally confirmed that if, these conditions are met, it is possible to achieve a high quality of the correction. Based on the obtained criteria, a technology for correcting defocusing with control over the stability of estimates is proposed. The results of image correction showing the effectiveness of the technology are presented.

The article explores the reliability of training samples used to train convolutional neural networks for the diagnosis of pulmonary diseases. It is shown that the sample, in which 3500 X-ray pictures of healthy patients and the same number of pictures of patients with tuberculosis, is very heterogeneous. When training on different parts of the sample and recognizing its various parts, significantly different results are obtained.

An image compression technology based on machine learning is developed. Segmentation of the original image into discarded and stored zones is applied. An algorithm of compression of stored zones based on the nested coverage of the image is used. Discarded zones are replaced by a reliable fake during decompression. Machine-learning algorithms based on autoencoders, convolutional and adversarial neural networks are used at all stages of compression technology (segmentation, pixel approximation of stored zones, fake of discarded zones, etc.). Computational experiments are performed to study the proposed compression technology and the included machine learning algorithms in natural images. The results of computational experiments confirm the prospects of the proposed technology for problems related to digital image compression.

A two-stage method for adaptive traffic signal control based on an estimate of the predicted weighted traffic flow passing through an intersection is proposed. At the first stage, we estimate the travel time required for each vehicle to pass the intersection using an artificial neural network model and estimate the predicted traffic flow through the intersection for a given phase of the traffic signal cycle. At the second step, a weighted flow estimate is formed, which takes into account the waiting time of vehicles. The proposed method for choosing the traffic signal phase is based on maximizing the weighted traffic flow. The results of experimental studies allow us to conclude that the proposed approach outperforms the classical approaches and state-of-the-art methods of traffic signal control based on reinforcement learning.

The results of numerical simulation based on the Mie theory of the superresonance effect for a dielectric sphere with a low refractive index are presented. Water is used as a material of the mesoscale sphere. It is shown that not only the previously studied weakly dissipative mesoscale spheres made of a material with a “medium” (about 1.5) and high (more than 2) refractive index, but also a low one (about 1.3) support the high-order Fano resonance effect associated with internal Mie modes. In this case, the intensities of resonant peaks for both magnetic and electric fields in the vicinity of the poles of the sphere can reach extremely high values of the order of 10⁶-10⁷ for a water droplet with a Mie size parameter of about 70.

We studied the communities of soil surface Coleoptera (Carabidae et Tenebrionidae) in the mountain hollows of Altai (Kurai and Chuya) and Tuva (Ulug-Khem and Ubsu-Nur; in the latter, the arid western sector and the more humid eastern sector were studied). Collections were made in the same habitats at intervals of about 60 years: in 1962-1963 and in 2018-2020. Climate changes over this period were analyzed. In general, the climate of the characterized steppe depressions retained the features of sharply continental, with negative mean annual temperatures, moisture deficit and high frequency of fluctuations of all parameters. In all regions an increase in average annual temperatures and in the last 10-20 years an increase in annual precipitation has been observed, most strongly in the Ulug-Khem hollow, creating preconditions for reduction of aridity of ecological conditions. Over 60 years, the number of beetles of the studied taxa has changed several times, sometimes by more than an order of magnitude. At the same time, the number of representatives of the more xerophilic Tenebrionidae family fell, while the number of the more mesophilic Carabidae increased. When comparing the proportion of tenebrionids in the population of different habitats in the 1960s with their proportion in 2018-2020, a sharp, several-fold decrease in their participation in the communities is observed in almost all cases. More beetle species with a more northern or broader (polyzonal and/or transpalaearctic) distribution are becoming more common in the Tuva basins. Such species are found in both humid and arid regions. These changes in species compositions and soil-dwelling beetle communities may reflect mitigating climatic conditions due to some increase in precipitation in the studied region. The mean values of the indices of species diversity and abundance do not differ in general for the “before” and “now” ecosystem states. There are also no reliable differences for total species richness and total abundance. But there are noticeable interannual differences for some diversity indices calculated for Altai ecosystems in 2018 and 2020. This may indicate that differences between the overall diversity indices of ground beetle communities in dry and wet years overlap the long-term trend caused by climate change, and populations of species with different life strategies in the communities respond quickly to these changes without losing the overall structural complexity of the animal population.

The ecological patterns of landscape differentiation of the fauna and bird population of the northern taiga of Central Siberia at altitudes of 100-1000 m a. s. l. have been analyzed. m. In 2002-2020 surveyed flat right bank of the river basin Lena and low-mountain areas of the Putorana Plateau and Vilyui Plateau. The route accounting method was used on transects of unlimited width. The commonality of the taxonomic structure and species composition of the nesting avifauna, numbering 156 species, is high. A number of species ( n = 14) were first recorded nesting at a distance of 100-250 km from the known boundaries of their ranges. The taxonomic structure of the nesting avifauna corresponds to the zonal and landscape features of the taiga of North Asia with the dominance of species from the orders of passeriformes, shorebirds, anseriformes, falconiformes, totaling 83 %. The avifauna of the northern taiga of Central Siberia is formed in a system of common zonal and altitudinal-belt patterns, unites species ecologically associated with forest and shrub vegetation, meadow, water, and mountain habitats. The most significant in the formation of the avifauna are the species of the Siberian (40 %) fauna type, boreal and boreal-hypoarctic zonal-landscape groups (41 %). The average population density of birds in the northern taiga larch forests is 261 ind./kmІ, in aquatic-semiaquatic habitats 8.5 ind./1 km of coastline. The bird population of larch forests is dominated numerically by the kuksha, willow, talovka, zarnichka, brown thrush, finch, common tap dance, baby bunting. Among the dominants of water and semiaquatic habitats there are 17 species, incl. wigeon, common teal, common tern, carrier, fifi, haley, glaucous gull, arctic tern.

In this article, the problem of specialization of rock ferns to the effects of environmental factors, realized at the morphological and anatomical level, is considered. The purpose of the article was to analyze the anatomical and morphological structure of the homosporous fern Woodsia glabella to identify its correlation with the petrophytic lifestyle in high latitudes. Woodsia glabella is a Holarctic species collected in the Komi Republic, in the Yugyd-va National Park in the clefts of rocks with moss cover. Based on the study, it was found that this obligate lithophyte (hazmophyte) has a relationship between structural features and extreme living conditions on damp rocks at different levels of the organization. At the organismal and organ levels, this is the nanism of sporophytes, which allows the rosette short-rhizomatous biomorph to occupy a warmer ground-level ecological niche; “bunch” biomorph, long-lasting leaf petioles, protecting the kidneys from the drying effects of cold winds, high temperatures, excessive insolation and transpiration; bunch is also involved in the accumulation of its own humus, providing geophitization, in which bryophilia plays an important role; leaf feathering which increases the overall photosynthetic surface in vegetation conditions during a short summer; a summer-green phenorhythmotype adequate to the climate; a tendency to deciduous and the ability to switch to sporulation in the early phases of ontogenesis with sporangia maturing at different times. At the cellular and tissue level, these are thin feather plates; large, chloroplast-containing epidermal cells with sinuous anticlinal walls; hypostomaticity; homogeneous loose mesophyll; low values of the dry weight of the plates; a small number of relatively large stomata per unit area; the presence of phlobafenes in the petioles that increase the resistance of the fern to changing environmental conditions. This study can shed light on the solution of many issues facing modern botany: the problems of structural evolution of plants, which are based on the processes of differentiation and specialization, diagnostics of species, adaptiogenesis, the doctrine of life forms, etc.

Coregonus sardinella Valenciennes in the Khatanga River basin (Taymyr Peninsula) was considered as a component of ichthyocenosis and was never the subject of special study. As well-known published materials show, Coregonus sardinella in the Khatanga River basin are represented by semi-anadromous, lacustrine and lacustrine-river forms. In this work the features of the size and age structure characteristics, fecundity, migration and fishing in modern conditions of the semi-anadromous form of Coregonus sardinella are analyzed. During the study period (2010-2018) fish with a length of 186 to 364 mm and a mass of 54 to 442 g have been spotted in the spawning stock of semi-anadromous Coregonus sardinella in the Khatanga River basin; an average of 275 mm in length and 163 g in weight at the age of 5+ to 15+ years. Males slightly prevailed over females in numbers (57.3 and 42.7 % respectively). The individual absolute fecundity (IAF) has been shown to vary from 4.6 to 36.7 thousand of eggs, on average 13.4 thousand of eggs, during the period 2010-2018. Individual relative fecundity (IRF) varied from 37.5 to 172 pcs/g of body weight, on average 88.4 pcs/g. The boundaries of the main spawning grounds were clarified, which are located on the section of the Kheta River from its mouth to the mouth of the Boganida River (a tributary of the Kheta River, 414 km from the mouth) and the Khatanga River, 20 km from the confluence of the Kheta and Kotuy rivers.

Trematodes of Plagiorchis genus are widespread endoparasites with a life cycle involving several hosts. The present work on the study of the second intermediate hosts of the genus Plagiorchris was carried out in the basin of Chany Lake, located in the forest-steppe of Western Siberia, where pass the migration routes of many species of aquatic and near-water birds - the final hosts of these trematodes. The work was carried out in 2014-2015 in the reed zone of the Fadikha Lake, which is the habitat of the first intermediate hosts of plagiorchids - snails. Representatives of the classes Insecta, Malacostraca, Gastropoda were studied to identify the potential second intermediate hosts of the genus Plagiorchis. In the Chany Lake basin, metacercariae of Plagiorchis genus (P. elegans и P. multiglandularis) were found only in insects from the order Odonata: the largest part of infected were larvae of Sympetrum vulgatum (68 %), followed by species S. flaveolum (18 %), S. sanguineum (9 %) and Aeshna serrata (5 %). The prevalence of metacercariae of the detected trematode species for 4 Odonata species during the study years varied in the range from 3.3 to 45.5 %, the intensity of invasion - from 2 to 4 trematodes per 1 odonate larva. Infection with metacercariae increased with the age of odonate larvae. The tendency of a positive relationship between the infection (prevalence) of the first (snails) and the second (odonate larvae) intermediate hosts was revealed. A reliable relationship has been established between the prevalence of the invasion of odonate larvae and the abundance of their populations, which varies throughout the season. Seasonal changes in the infection of odonates with metacercariae of Plagiorchris genus are associated with the phenology of these insects: periods of increased infection were recorded on the eve of the mass emergence of odonates, when the number of odonate larvae in the reservoir is extremely high, and vice versa, periods of decline in infection were noted after the mass metamorphosis of odonates.

The paper contains original data on the composition and structure of Oligochaeta communities in the zone of influence of wastewater from a pulp and paper industry (the Vychegda River, the Northern Dvina River basin). 40 species and forms of oligochaetes have been identified. We found species having been earlier identified only in tributaries, in floodplain water bodies and in lakes of the Vychegda River basin. By the diversity index (Shannon index (H_N) and Simpson index (D_S)), evenness index (Pielow index (E)), and Whittaker (βw ) indices, the studied section of the river exceeds the control section by the species diversity. There is a significant increase in abundance and biomass of oligochaetes in comparison with section higher up the river. Based on the correlation analysis between the quantitative development indicators of oligochaetes with the environmental parameters (type of substrate, presence of algal growths and macrophyte, depth, chemical composition), the assessment of biotopic confinement of species (F_j) and conjugate between species (r_A), we found out that the distribution of oligochaetes in the study area largely depends on the type of substrate. According to the obtained results on the assessment of diversity and distribution of oligochaetes in the zone of influence of wastewater from a pulp and paper industry, the appearance of technogenic parts with artificial substrate along the shore line leads to changes in the composition, diversity and quantitative development characteristics of benthic organisms.

An analysis of the variability in the development of Scutellaria baicalensis Georgi (Lamiaceae) plants collected from natural habitats (Zabaikalsky Krai, Amur Region, Primorye) and grown under the same culture conditions (Novosibirsk) is given. It has been established that in S. baicalensis, under new growing conditions, interpopulation differences in morphological characteristics and the timing of the onset of phenophases developed in nature are preserved. Data analysis shows the existence of significant differences ( t > 3) between the steppe Zabaykalsky and forest Primorsky cenopolations (CP) in plant height, number of pairs of leaves, number of shoots both in nature and during introduction. The flowering period in the Zabaykalsky CP comes earlier, compared to the Primorsky CP, both in nature and in culture. In Zabaykalsky CP in culture, individuals bloom in early July. In the Primorsky CP, the flowering period begins at the end of July-August, the seed ripening period is extended, especially in the first years of introduction. The formation of steppe Zabaykalsky and forest Primorsky ecotypes can be assumed.

The article presents the results of the analysis of the peculiarities of renewal of woody vegetation after a crown fire which broke out in 2010 in the beech-yew forest in the Termenlik district (965 m a. s. l.) on the south-eastern slope of Gimrinskiy Khrebet in the Foothill Dagestan (East Caucasus). For the description of the changes which occurred on the post-fire spot in 2019 there have been arranged eight sample areas (SA) 100 square metres each (10 × 10 m). A geobotanical description of the sample area has been conducted according to the generally accepted method which included the definition of the microrelief, the species composition (species richness) of the trees, their distribution in the layers and biometric parameters. For each treespecies there has been revealed a projective cover in percentage as well as the abundance, the sequence of penetration and distribution, the dynamics of the development of the above-ground part and there have been evaluated the results of their competitive interaction. Owing to the appearance of new species of seed origin with accelerated growth in the composition of the forest stand, such as Populus tremula L., Salix caprea L., Acer campestre L., Fraxinus excelsior L., a suggestion has been made about the change of the succession trend and the formation of a new reformed cenosis without participation of the basic dominant species of the primary forest, namely Fagus orientalis Lipsky., Carpinus caucasica L., Taxus baccata L., Acer platanoides L. There has been offered a method of mechanical removal of the dominant species P. tremula leading to the enhancement of the competitive advantages of the pioneer species characteristic of this locality. It is believed that such a method will lead to an increase in the competitive advantages of other species with a predictable consequence. Thus, in the studied community of the burned area, vegetation development will change towards the initial beech-yew forest for this area, and not a community dominated by aspen.

The paper summarizes the results of field studies of carbon dioxide and methane fluxes in peatland ecosystems on the territory of license areas of the Salym group of oil fields (Khanty-Mansi Autonomous Okrug). The largest fluxes of carbon dioxide and methane are observed in mesotrophic and eutrophic bogs, which are characterized by the maximum of biomass storages. Significant negative CO₂ fluxes (-1161.6 mg CO₂ m^-2∙h^-1) associated with photosynthesis have been recorded here, but they also have a high emission component of carbon exchange (ecosystem respiration) (more than 680 mg CO₂ m^-2∙h^-1). Methane emission reaches 23.9 mg CH₄ m^-2∙h^-1. In oligotrophic bogs, in the daytime, fluxes of СО₂ in range from -400 to -600 mg CO₂ m^-2∙h^-1 were recorded, and at night from + 160 to +840 mg CO₂ m^-2∙h^-1. Methane fluxes from hummocks in oligotrophic bog complexes were up to 1.1 mg CH₄ m^-2∙h^-1, and from decreases 3.9 mg CH₄ m^-2∙h^-1 from hollows. Large carbon dioxide and methane fluxes were registered from the surface of clear-cuts at a pine-dwarf-shrub-sphagnum bog, where, depending on the ground cover, the release of CO₂ can be from +46 to +480 mg CO₂ m^-2∙h^-1, and emission of CH₄ - up to 4.6 mg CH₄ m^-2∙h^-1.

According to the results of studies of the Vasyugan River in July 2019 and 2021 the species composition, taxonomic structure, dominant complex, abundance and biomass, indices of phytoplankton biodiversity were established for the first time. 166 species and intraspecific taxa of algae from 8 divisions have been identified, green algae (Chlorophyta division) form the basis of species richness. The dominant phytoplankton complex includes centric diatoms, green algae and non-heterocyst cyanoprokaryotes. Biodiversity indices indicate high species richness, close to average complexity and evenness of the phytoplanktocenosis structure. The trophic status of the river corresponds to the eutrophic category of waters, the water quality ranges from class 3 “satisfactory purity” to class 4 “polluted”.

An analysis of the phenological development of 13 taxa of North American maples for 2013-2020 was carried out. on the basis of the collection of the South Ural Botanical Garden-Institute of the Ufa Federal Research Center of the Russian Academy of Sciences. The sum of positive, effective and active temperatures, as well as the sum of precipitation required for the onset of the main phenophases, has been established. Most phenophases depend on weather conditions, except for the phases of the beginning and end of flowering, fruit ripening - they are genetically determined. This explains the large difference in the sum of temperatures and precipitation at the beginning of these phases in different species. The sum of positive temperatures at the beginning of flowering is 11-497 °C, the amount of precipitation is 33-80 mm. At the end of flowering, the sum of positive temperatures at the beginning of flowering is 149-722 °C, the amount of precipitation is 43-112 mm. The number of positive temperatures attributable to the phenophase of fruit ripening varies from 693 to 2662 °C, the amount of precipitation by this time is from 47.5 to 315 mm. The duration of vegetation of North American maples in Ufa, depending on the species, ranges from 140 (A. tschonoskii) to 172 days (A. rubrum ‘Sommer Red′).

Toxicity of bottom sediments from some areas of the Peter the Great Gulf has been studied using bioassay with embryos and larvae of the sand dollar Scaphechinus mirabilis (Agassiz, 1864). Based on the calculation of the integral toxicity index (ITI), different inhibition rates of early larval development are identified in elutriate from the bottom sediments. The effects are the most negative in the coastal zone of the Vladivostok in Gornostay Bay (Ussuriysky Bay) and in the Kozmina Bay (the Nakhodka Bay). Larvae in elutriate from the were characterized by significant anomalies, and the ITI was maximal (ITI = 10). A high percentage of abnormally developed larvae was detected in a sample from Podyapolsky Bay (ITI = 6.08). The results of the study confirm the decrease in the anthropogenic press on the Peter the Great Gulf, except for of local areas adjacent to sea ports and a reclaimed solid domestic waste landfill.

To date, compounds having an adamantane moiety have found wide application in the pharmaceutical industry. Despite the fact that most biologically active adamantyl-bearing derivatives contain substituents in the first position of the adamantane molecule, some derivatives with substituents in the second position have also shown valuable pharmacological properties. While 1-adamantanecarboxylic acid is an inexpensive and commercially available reagent, its 2-substituted analogue is substantially less available, and therefore, the development and optimization of approaches to the synthesis of 2-adamantanecarboxylic acid are of great importance. In this work, a three-stage method for the synthesis of 2-adamantanecarboxylic acid has been optimized, based on the Corey-Chaykovsky reaction of 2-adamantanone with trimethylsulphoxonium iodide in the presence of potassium hydroxide, followed by acid-catalyzed opening of the oxirane ring and oxidation of aldehyde 9 to the target carboxylic acid. The total yield of the target product is 70 %.

The dianion generated by the reduction of terephthalonitrile with sodium in liquid ammonia arylates di- and trifluorobenzonitrites replacing the ortho - and para -fluorine atoms, as well as the para -hydrogen atom, with the para -cyanophenyl fragment. The orientation of the interaction, the structure of the resulting fluorinated 4,4'- and 2,4'-dicyanodiphenyls, and reaction productivity are determined by the location and number of fluorine atoms in the starting benzonitrile.

1-Alkoxy-3-imidazolines derived from stable nitroxide radicals, as well as nitroxide radicals themselves, bearing the 2-pyridyl substituent in position 2, under mild conditions undergo acid-catalyzed rearrangement with the fragmentation of the imidazoline ring and the formation of imidazo[1,5-a]pyridine. This rearrangement does not occur in superacid media due to the protective protonation of the nitrogen atom of the pyridyl substituent.

For the analysis of fluorine in difficult-to-burn and complex organofluorine compounds, special additives have been developed to ensure complete decomposition of the substances. Using a spectrophotometric technique based on the formation of а fluoride complex with lanthanum alizarin complexone, various organofluorine compounds have been analyzed with fluorine content of 1.5 to 70 % containing heteroelements in their structures: sulphur, chlorine, bromine, phosphorus, boron, selenium, tellurium in various combinations, as well as metals. The error of determination was established to be not higher than 0.5 abs. %

The effect of leuzea (Rhaponticum carthamoides) and cranberry (Vaccinium oxycoccus) meal extracts composition at a dose of (70 + 500) mg/kg, as well as individual active substances (ecdisten and ursolic acid) in equivalent doses, on the biochemical parameters of physical endurance (lactate, glucose) in the forced swim test on CD-1 male mice is investigated. It has been established that the developed composition exhibits pharmacological effects similar to those of the individual active substances promoting a decrease in the concentration of glucose (in blood) and lactate (in blood and in muscles).

The formation of a complex of magnesium and 4-ethylterpiridyl-(N-tert-butyl-N-(1-diethylphosphone-2,2-dimethylpropyl))-nitroxide alkoxyamine (SG1-tpy) was investigated by means of NMR spectroscopy. The stoichiometry of the complex was determined by constructing the Job’s plot. The homolysis rate constant of the alkoxyamine used was determined by means of EPR spectroscopy, and the activation energy was estimated. Polystyrene was obtained by radical controlled polymerization, and its molecular weight characteristics were studied by gel-permeation chromatography. When magnesium trifluoroacetate is added to the polymer solution, the molecular weight of the polymer increases, which indicates the formation of the complex. Polystyrene was also synthesized using the complex form of the initiator. It is shown that all the obtained polymers are narrowly dispersed, polydispersity is less than 1.5.

Copolymer of 2-(4-acryloylpiperazin-1-yl)methyl)-9H-thioxanthen-9-one and methyl methacrylate was synthesized by radical polymerization. This copolymer has high molecular weight characteristics and is capable of forming long-lived anion radical states of the pendant thioxanthenone groups during electrochemical reduction. Using a combination of electrochemical and optical methods, it has been shown that the electronic states of the pendant groups are located within the band gap of methyl methacrylate and may promote the Frenkel mechanism of conductivity in dielectric thin films used in resistive memory devices.

Mass spectrometric characteristics of N-alkyl-4-nitro-1,2,3-triazoles were investigated using a gas chromatograph with a quadrupole mass spectrometric detector in the mode of electron ionization (70 eV). The stability of the molecular ion was studied depending on the position, structure and nature of the alkyl substituent at the endocyclic nitrogen atoms of nitrotriazole heterocycle. N2-alkyl-4-nitro-1,2,3-triazoles were found to have the highest stability and molecular ion intensity, independently of the alkyl substituent in the structure of the compound. The pathways of molecular ion fragmentation are proposed for the compounds under consideration, and characteristic ions are identified. Molecular ion fragmentation in N-alkyl-4-nitro-1,2,3-triazoles was discovered to start with the elimination of the exocyclic NO₂ group, followed by detachment of the respective alkyl substituent and generation of the cation radical of 1,2,3-triazole. Fragmentation of non-substituted cation radical of 1,2,3-triazole proceeds through characteristic detachment of N atom or neutral molecules N₂ and HCN. In turn, the ionic decay of bulky alkyl substituents (cyclohexyl and benzyl radicals) leads to a group of characteristic ions with high relative intensity. In general, the findings demonstrate that mass spectrometry can be efficiently used for robust identification of structural isomerism ( N1-, N2- and N3-isomers) of alkyl-4-nitro-1,2,3-triazoles and the products of their decomposition.

Vitrinite concentrates of coal at different stages of metamorphism are studied by means of scanning electron microscopy and X-ray diffraction analysis. The results show that the cleaves and fractures on the surface of maceral particles have a structure characteristic of vitreous amorphous bodies for the whole metamosphism series. An increase in metamorphism degree is accompanied by an increase in the electrical conductivity of vitrinite particles and a decrease in the reflectivity with respect to electrons due to a decrease in the content of oxygen atoms. It is shown by means of X-ray diffraction that vitrinites have a turbostratic carbon structure, formed by polyarene layers with the interlayer spacing (d₀₀₂) decreasing from 3.64 to 3.50 Å with an increase in metamorphism stage, at the same time an increase in the dimensions of structured vitrinite fragments - height (L_c) andd width (L_a) of arene layer packets - is observed. A linear dependence is revealed between d₀₀₂ and vitrinite reflectance.