Vol 20, No 3 (2024)

For the first time, an exact solution of the three-dimensional Wiener-Hopf integral equation is given, one-dimensional and two-dimensional versions of which are widely used in mixed, including contact problems. The equation in question can be abstractly represented as the action of a three-dimensional stamp on a four-dimensional half-space or layer. In the work, in relation to contact problems of mechanics, as well as seismology, an application of this method was found. It consists in the fact that along with two geometric coordinates, the time coordinate extending along the entire axis is taken as the third. It allows you to introduce a change of condition at zero for stresses, moving in the contact zone from their values to their velocities. Attempts at an analytical or numerical solution of this problem are not known to the authors. The results may be useful in the fields of using the Wiener-Hopf equation in probability theory and statistics, where one-dimensional variants are used, as well as in seismology. Just as in the two-dimensional case, a universal modeling method based on block elements is used in the study.

The results of the study of soil cover of the island part of the Don delta are represented. It is found that the main type of soil is alluvial; alluvial-meadow, meadow-alluvial, alluvial meadow-marsh and alluvial sandy soils on soil-forming rocks of different genesis are widely spread. The soil profile of alluvial soils is characterized by heterogeneity and clear horizontal layering with alternation of sandy layers with dark loamy interlayers, as well as layers of sandy-shell alluvium. According to the data of granulometric composition most of alluvial soils are represented by light loamy, medium loamy, sandy loam and sandy varieties. It was revealed that alluvial soils of light loamy, sandy loamy and sandy composition are characterized by humus content of 1.56-2.54%. In meadow-alluvial and alluvial meadow-marsh soils of medium-loamy and heavy loamy composition humus content in upper horizons does not exceed 3.15%, down the profile decreases to 0.84%. Distribution of carbonates (CaCO3) in the profile of alluvial soils does not have a general pattern, mainly they have low values not exceeding 6.2%. Density index for upper light loamy layers is 1.15-1.23 g/cm3, underlying sandy loamy and sandy layers not more than 1.08 g/cm3. For alluvial soils with more heavy granulometric composition does not exceed 1.54 g/cm3. It was noted that most of the studied alluvial soils are not saline, and have medium alkaline reaction of 8.0-8.2 in terms of pH.In the current period in the formation of alluvial soils the leading factor of soil formation is alluvial, in which the features of the alluvial strata and the way of alternation of layers of different granulometric composition have a significant impact on the direction of soil formation process in the structure of the soil profile of the islands. In general, along with the alluvial process, the formation of various subtypes and varieties of alluvial soils occurs during the development of such elementary soil-forming processes as floodplained, turf formation and gley formation.

The article, based on state statistics, conducted a study of the transformation of geography and trends in the development of migration of the population of the Southern Federal District. Using an interdisciplinary integrated approach, an analysis of migration flows, their directions, scale and intensity was carried out, the geography of migrations of the most migratoryly attractive subject of the district - Krasnodar Territory - was determined, and mapping of migration indicators was carried out using modern information technologies for studying space and visualization.It is shown that, despite the decrease in migration turnover due to the coronavirus pandemic, the long- term trend of positive migration dynamics in the Southern Federal District has remained, and in terms of the intensity of net migration in 2021, the macroregion took first place among all Russian districts.There have been no major changes in the geography of incoming and outgoing migration flows. Intra- Russian migration is characterized by a migration outflow of the population to the Central and Northwestern federal districts, and migrants from all other districts, but most of all from Siberia and the Far East, come to the southern macroregion. The main flows of international migrants come from citizens of the CIS countries, primarily from Ukraine, Armenia, Kazakhstan, Tajikistan, Uzbekistan, and Azerbaijan.A comparative analysis of the migration movement of the subjects of the Southern Federal District showed that in the macroregion Krasnodar Territory ranks first in terms of the volume and effectiveness of migration, and in terms of the intensity of migration movement, it exceeds the Russian average. To date, the steady trend of positive dynamics in the migration balance that has developed in Kuban since the middle of the last century has been preserved. However, there has been a significant decline in net migration. The main modern vector of intra-Russian migration flows is movement to Kuban from the northern regions of Russia, Siberia and the Far East. Most international migrants arrived in the Krasnodar region from CIS countries. During the study period, the main suppliers of cross-border migrants were Ukraine, Armenia and Kazakhstan.

Vital spectra are one of the most biologically important population characteristics. Currently, the study of the vital signs of rare species, which include the object of study Tulipa biebersteiniana Schult. et Schult. fil. (Liliaceae), is becoming increasingly actual. This work is devoted to the study of the vitality of specimens and the vital structure of coenopopulations of T. biebersteiniana in different parts of the Ergeni Upland. The study was carried out during two growing seasons (2022‒2023) in five coenopopulations from different plant communities confined to light chestnut soils of varying degrees of salinity. The vitality of specimens in the studied coenopopulations of T. biebersteiniana, estimated by the IVI index, varied widely – from 0.448 to 1.686. At the same time, the difference between the maximum values of individual vitality of specimens in most coenopopulations was greater in the second year of the study. The vitality values of the studied T. biebersteiniana cenopopulations, expressed by the IVC index, ranged from 0.800 to 1.270, which is consistent with the data provided in the literature. The dynamics of the values of the vitality index of T. biebersteiniana coenopopulations revealed a clinal character, increasing from the northern to the southern part of the Ergeni Upland. The highest values of the vitality index in the coenopopulations of T. biebersteiniana in the southern part of the Ergeni indicate the most favorable conditions for realizing the potential of the species in this part of the upland. The conditions of the second year of research, which were wetter and with a higher temperature during the period of plant growth and development, contributed to an increase in the vitality of both specimens and coenopopulations of T. biebersteiniana. The studied coenopopulations of T. biebersteiniana belonged to the vital type “prosperous”.

Ecotone ecosystems “water-land” are natural ecosystems formed at the interface of interaction between two environments: aquatic and terrestrial, have a specific structure, functioning regimes, and stability mechanisms. Detailed research of the ecotone systems of the storage ponds of Kalmykia is necessary for the preservation of the gene pool of steppe and desert biota.The Keltrikan reservoir belongs to the Sostinskie lakes system, located in the southeast of the Republic of Kalmykia. The study of the water body and the surrounding territories was carried out according to the ecotone concept of V.S. Zaletaev. Studies had shown that by 2023, the area of the water surface of the Keltrikan reservoir decreased by 2.8 times compared to 2009. It was found that the waters of the Keltrikan reservoir have high mineralization, reaching up to 169 g/l, with the salinization type being sulfate-sodium-chloride. Research had shown the Keltrikan reservoir, being the most distant from the Sostinskie lakes network, is highly dependent on water supply from the Chogray water storage. For the first time, structural-functional blocks of the ecotone system were described for this water body, the depth of occurrence and mineralization of groundwater in each block were determined, geobotanical descriptions of the blocks were performed, their floristic and phytocenotic composition and biological productivity were identified. It was found that the general species richness of the Keltrikan reservoir ecotone has 45 species of higher flowering plants, belonging to 33 genera and 11 families. The most numerous families are Chenopodiaceae (42.2%), Brassicaceae (15.6%), Poaceae (13.3%), Asteraceae (6.7%). Annuals and perennials dominate in the flora, but the edificators of the ecotone flora of the Keltrican reservoir are dwarf semishrubs and shrubs. Most plant species belong to xerophytes and mesophytes.

New information on the presence of 27 rare, protected or little-studied species and subspecies of birds (greylag and red-breasted geese, common shelduck, gadwall, common pochard, Eurasian oystercatcher, pied avocet, black-winged stilt, Eurasian golden-plover, Eurasian curlew, sanderling, common greenshank, yellow-legged, great black-headed, Mediterranean, slender-billed, and little gulls, Caspian tern, European turtle-dove, great white and dalmatian pelicans, squacco heron, glossy ibis, Eurasian spoonbill, lesser spotted and white-tailed eagles, Eurasian hobby) obtained in the Temryuk region (Eastern Azov region) in different seasons of 2022-2023. The coast of the bay is a stopping place on the spring migration of Eurasian oystercatcher, pied avocet, Eurasian golden-plover, Eurasian curlew, sanderling, common greenshank, common shelduck, slender-billed gull, and Caspian tern; in the fall - pied avocet, sanderling, and Caspian tern. Information about the migration of the sanderling at the end of March has been obtained for the first time. The location of the concentration of Caspian tern and slender-billed gull has been identified. The glossy ibis, the number of which is growing, the black-winged stilt, and the great black-headed gull remain in the spring-summer period in the flooded rice fields. Harvested rice fields provide valuable habitat for Eurasian spoonbills during their fall migration. Information about a large aggregation of red-breasted goose in rice fields in January 2023 is presented for the first time. The great black-headed gull is found on estuaries in all seasons. The common pochard, gadwall, little gull, and Dalmatian pelican stop at the estuaries during the migration period. The migration of the lesser spotted eagle at the end of September and the migration of a large flock of great white pelican in May were recorded in this area for the first time. The squacco heron, which is disturbance tolerant, is common in reed habitats of estuaries and irrigation canals.

Fucoidans are sulfated heteropolysaccharides from brown seaweed, known for anticoagulant, anti- inflammatory, antiviral and other properties. The method of administration and the dosage form of the medicinal substance have a significant impact on the bioavailability of the drug, as well as on its metabolism in the body.The purpose of the work was to evaluate the effect of fucoidan from Fucus vesiculosus on the indicators of the antioxidant system in mice with experimental streptozotocin-induced diabetes when administered intragastrically and externally.To evaluate the antioxidant properties of fucoidan in vivo , diabetes mellitus was developed in mice by intraperitoneal administration of streptozotocin and a 1% solution of nicotinic acid. Fucoidan in two dosage forms was administered for 10 days after the formation of the pathology at a dose of 50 mg/kg in the form of tablets intragastrically and 10 mg per animal in the form of an ointment when applied externally. To assess the antioxidant status of animals, the concentration of thiobarbituric acid-reactive products (TBA-RP) in the blood plasma, the level of reduced glutathione (GSH) and catalase activity (CAT) in the erythrocytes were determined.In mice with streptozotocin-induced diabetes against the background of pathology, the process of lipid peroxidation intensified and the effectiveness of the antioxidant system decreased. Fucoidan from F. vesiculosus suppresses systemic oxidative stress in mice with induced type 2 diabetes mellitus. This is achieved due to the inhibition of excessive generation of pro-oxidants (TBA-RP) and a protective effect on the factors of the antioxidant defense system (catalase activity and glutathione content). To the greatest extent, fucoidan, when administered intragastrically, prevents the formation of pro-oxidants, while when applied externally, it has a protective effect to a greater extent due to the activation of antioxidants.

В 2022 г. в состав Российской Федерации вошли новые южные регионы - Донецкая Народная Республика, Луганская Народная Республика, Запорожская и Херсонская области. Новые регионы - это не только территории, но и люди, новые россияне, в том числе и научное сообщество, которым вместе со всей Россией предстоит не только решать текущие проблемы и купировать угрозы, но и думать о будущем, восстанавливать исторические регионы Новороссии. Именно этим вопросам, поиску их решения и была посвящена международная конференция «Стратегические проблемы, угрозы и риски Азовского бассейна и Приазовья». Формат конференции был задан несколько лет назад, и всегда основной вопрос, обсуждаемый научным сообществом на площадке Южного научного центра Российской академии наук, - это развитие юга России. Именно этим проблемам много лет большое внимание уделял член-корреспондент РАН Дмитрий Геннадьевич Матишов (1966-2015) - основатель и первый директор Азовского филиала Мурманского морского биологического института РАН, Института аридных зон ЮНЦ РАН, кафедры океанологии Южного федерального университета. Памяти выдающегося ученого и организатора науки была посвящена международная конференция, проведенная в Ростове-на-Дону при неизменной поддержке Российского центра научной информации (РЦНИ - РФФИ)