bluuebunny/crossref_metadata_2025 huggingface dataset:
Quasidifferentiability and Uniform Observability of Linear Time-Varying Singularly Perturbed Systems
Authors: Tsekhan O. B
Published: April 2024

For linear time-varying singularly perturbed systems (LTVSPS) with quasidifferentiable coefficients and a small parameter multiplying some derivatives, the problem of uniform observability is considered. Necessary and sufficient conditions for the quasidifferentiability of the set of output functions independent of the small parameter are proved, observability matrices independent of the small parameter for the slow subsystem and the family of fast subsystems associated with the LTVSPS are constructed, and a connection is established between them and the observability matrix of the original system. On the basis of the complete decomposition of the original LTVSPS with respect to the action of the group of linear nonsingular transformations, we prove rank sufficient conditions for the uniform observability of the LTVSPS that are independent of the small parameter and valid for all sufficiently small values of it. The conditions are expressed in terms of the observability matrices of the slow subsystem and the family of fast subsystems of smaller dimensions than the original LTVSPS.
On Asymptotics of the Spectrum of an Integral Operator with a Logarithmic Kernel of a Special Form
Authors: Polosin A. A.
Published: April 2024

We study the asymptotic behavior of the spectrum of an integral operator similarto an integral operator with a logarithmic kernel depending on the sum of arguments. Bya simple change of variables, the corresponding equation is reduced to an integral equation ofconvolution type defined on a finite interval (as is well known, such equations in the general casecannot be solved by quadratures). Next, using the Fourier transform, the equation is reduced toa conjugation problem for analytic functions and then to an infinite system of linear algebraicequations, the isolation of the main terms in which allows deriving a relation that determinesthe spectrum of the original problem.
Searching for Parameters of a Model with the Best Local Controllability
Authors: Velishchanskiy M. A. , Chetverikov V. N.
Published: April 2024

We study the problem of optimal choice of model parameters with respect to anyfunctional. Locally controllable affine systems and integral functionals depending on the programcontrol are considered. Local controllability of affine systems with nonnegative inputs isproved in the case where the columns multiplying the controls form a positive basis. For suchsystems, we introduce the local controllability coefficient and pose the problem of its maximizationdepending on the choice of model parameters. As an example, we consider a very simplifiedmodel of an underwater vehicle and study the problem of finding an arrangement of its controlpropellers in which the energy consumption of the vehicle is minimal.
Synthesis of new condensed pyrano[4,3-b]pyridines based on ethyl-3-aminopyrano[4,3-b]thieno[3,2-e]pyridine2-carboxylate derivative
Authors: Dabaeva V. V , Bagdasaryan M. R , Paronikyan E. G , Barkhudaryants I. M , Panosyan G. A , Stepanyan G. M , Dashyan Sh. Sh.
Published: April 2024

Methods for the synthesis of new fused pyrano[4,3- b ]pyridine derivatives based on the ethyl-3-amino-pyrano[4,3- b ]thieno[3,2- e ]pyridine-2-carboxylate derivative have been developed. The interaction reactions of the condensed 3-(phenoxycarbonyl)-amino derivative with primary and secondary amines have been studied. It has been established that in the case of primary amines, the reaction is accompanied by cyclization with the formation of fused pyrimidines. However, when secondary amines are used, the structure of the final product depends on the reaction conditions. The antibacterial properties of the synthesized compounds were studied.
Synthesis of 1-antipyryl-1H-pyrrol-2-ones by interaction N-antipyryl substituted enamines with oxalyl chloride
Authors: Denislamova E. S , Lyadov V. A , Makrushin D. E , Ryabov V. G , Dmitriev M. V , Maslivets A. N
Published: April 2024

Methyl 4-aryl-2-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1 H -pyrazol-4-ylamino)-4-oxo-2-butenoates react with oxalyl chloride to form methyl 3-aroyl-2-chloro-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1 H -pyrazol-4-yl)-4-hydroxy-5-oxo-2, 5-dihydro-1 H -pyrrole-2-carboxylates, which are hydrolyzed to methyl 3-aroyl1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1 H -pyrazol-4-yl)-2,4-dihydroxy-5-oxo-2,5-dihydro-1 H -pyrrole2-carboxylates, the structure of which was confirmed by X-ray diffraction analysis.
Mass-spectra of new heterocycles: XXV. electron impact study of N-[5-amino-2-thienyl]thioureas
Authors: Klyba L. V , Sanzheeva E. R , Nedolya N. A , Tarasova O. A
Published: April 2024

The mass spectra of previously unknown N -(5-amino-2-thienyl)thioureas obtained in one preparative step from propargylamines and isothiocyanates were studied for the first time, and the main patterns of their fragmentation under electron ionization conditions (70 eV) were revealed. All thienylthioureas studied form a molecular ion ( I rel 7-61%), whose general direction of fragmentation {with the exception of N -[5-(diethylamino)-2-thienyl]- N , N '-diphenylthiourea} is the breaking of the R1N-C(=S) bond with the formation of the [ M - R2NHCS]+ ion, the peak of which has a high intensity ( I rel 35-85%). The dominant direction of fragmentation of the molecular ion N -[5-(diethylamino)-2-thienyl]- N , N '-diphenylthiourea is associated with the degradation of the thiophene cycle by C2-S and C4-C5 bonds. For N -(5-pyrrolidine-1-yl-2-thienyl)- and N -(5-piperidine-1yl-2-thienyl)thioureas are characterized by the course of intensive specific rearrangement processes, manifested in the appearance of unexpected channels of primary fragmentation of the molecular ion, the main of which is the elimination of the molecule N , N '-dimethylcarbodiimide.
Synthesis of phenylcycloalkylpolycarboxylic acids
Authors: Firstova A. A , Kofanov E. R
Published: April 2024

Synthesis previously undescribed tri- and tetracarboxylic acids containing aromatic and alicyclic fragments. It is known that some compounds with a phenylcycloaliphatic fragment are potential therapeutic agents for the treatment of cancer, Alzheimer’s disease, and some other diseases.
The povarov reaction in the synthesis of N-polycyclic compounds with a tetrahydroquinoline fragment
Authors: Limantseva R. M , Savchenko R. G , Odinokov V. N , Tolstikov A. G
Published: April 2024

The review is devoted to the analysis of the data synthesized biologically active tetrahydroquinoline derivatives based on the Povarov reaction and its three-component modification over the past 8 years.
Synthesis and properties for enaminoketoamides of 2,2-dimethyl-2,3-dihydrobenzo[f]isoquinoline series
Authors: Mikhailovskii A. G , Peretyagin D. A
Published: April 2024

The reaction of 1-R-6,6-dimethyl-5,6-dihydrobenzo[ f ]pyrrolo[2,1- a ]isoquinoline-8,9-diones (R = H, morpholinocarbonyl) with ammonia, morpholine, aniline and 1-naphtylamine proceeds with opening of dioxopyrroline cycle and forming enaminoketoamides. The conditions of reaction depends on the nature of nucleophile: ammonia and morpholine readily react at 20°C, the reaction with aromatic amines requires reflux in glacial acetic acid.
Interaction of 3-(2-pyridyl)-1,2,4-triazine-5-carbonitriles with 2-amino-4-aryloxazoles in the absence of water
Authors: Rammohan Aluru , Krinochkin A. P , Kopchuk D. S , Shtaitz Ya. K , Sharafieva E. R , Gaviko V. S , Zyryanov G. V , Chupakhin O. N
Published: April 2024

Recently we described the solvent-free interaction of 5-aryl-3-(2-pyridyl)-1,2,4-triazine-5-carbonitriles and 2-amino-4-aryloxazoles to form 4,5-diaryl-3-hydroxy-2,2'-bipyridine-6-carbonitriles. It turned out that under absolute (anhydrous) conditions this reaction resulted in the formation of two products, namely, the previously described 4,5-diaryl-3-hydroxy-2,2'-bipyridine-6-carbonitriles (yields up to 44%) and 4,5-diaryl-2,2'-bipyridine-6-carbonitriles (yields up to 32%).
Reaction of 2-hydroxy-5-methylacetophenone chalcones with guanidine in the presence of hydrogen peroxide
Authors: Mamedov I. G. , Khrustalev V. N.
Published: April 2024

In the presented work, the reaction of two 2-hydroxy-5-methylacetophenone chalcones and guanidine was investigated in the presence of hydrogen peroxide. Depending on the structure of the chalcones a 4.6-diaryl-2-aminopyrimidine or flavanol was obtained. The structures of the obtained products were elucidated by NMR spectroscopy and X-ray crystallography. Reaction route formation of compounds was proposed.
Interaction of 1,2,4-triazine-5-carbonitriles with 5-hydroxyethylsulfanyl- and 5-hydroxyethoxyethylsulfanyl-3-amino-1,2,4-triazoles
Authors: Krinochkin A. P. , Ladin E. D. , Shtaitz Ya. K. , Kudryashova E. A. , Kopchuk D. S. , Gorbunov E. B. , Shafran Yu. M. , Zyryanov G. V. , Rusinov V. L.
Published: April 2024

The solvent-free interaction of 1,2,4-triazine-5-carbonitriles with first synthesized 5-hydroxyethylsulfanyland 5-hydroxyethoxyethylsulfanyl-3-amino-1,2,4-triazoles at heating has been studied. It was shown that the presence of these substituents at the C5 position of 1,2,4-triazole changes the direction of the reaction, and 5-amino-1,2,4-triazines are formed as the main products, while the products of the ipso -substitution of the C5-cyano group containing the moiety of the substituted 1,2,4-triazole were isolated only as by-products. In the case of using 1,2,4-triazole with a fragment of monoethylene glycol at C5 position of triazine, the formation of a complex mixture of products occurred.
Coupled electroreduction of CO2 and H+ in the presence of substituted salts of 2,2'-bipyridine
Authors: Okina E. V. , Klimaeva L. A. , Chugunov D. B. , Kostryukov S. G. , Kozlov A. Sh. , Tarasova O. V. , Yudina A. D.
Published: April 2024

The possibility of conjugate electroreduction of carbon dioxide and hydrogen in the presence of 2,2'-bipyridine and its N -substituted salts in the presence of acids with different pKa values was studied. It was revealed how the strength of the acid affects the efficiency of the process; in particular, it was determined that the presence of methylsulfonic acid in the system promotes the conjugate formation of hydrogen and the reduction of carbon dioxide to formic acid. Probable mechanisms for the reactions occurring have been proposed.
Seminar “New organic functional materials”
Authors: Kashina M. V. , Kinzhalov M. A.
Published: April 2024

The “New Organic Functional Materials” seminar took place at St. Petersburg University as part of the All-Russian Conference featuring international participation that centered on “Ideas and Legacy of A.E. Favorsky in Organic Chemistry” from July 3-6, 2023. The seminar featured reports on organic materials possessing luminescent, photosensitizing, magnetic, conductive properties, and biological activity. The event also discussed innovative techniques for synthesizing functional organic molecules and their crystallochemical design. The review includes concise annotations of the reports and relevant references to the speakers’ works.
CAUSES OF THERMAL SUFFOSION ATTENUATION ON THE BESTYAKH TERRACE OF THE LENA RIVER, CENTRAL YAKUTIA
Authors: Gagarin L. A. , Olenchenko V. V. , Pavlova N. A.
Published: April 2024

This paper presents the results of thermal suffosion study in the Ulakhan-Taryn Creek valley, Central Yakutia, where intrapermafrost groundwater is discharged. Interpretation of satellite images and analysis of field data from landscape surveys, electrical resistivity tomography studies and ground temperature observations were used to determine the factors contributing to the attenuation of thermal suffosion in sandy deposits of the IV (Bestyakh) terrace of the Lena River. Successional stages of revegetation in the accumulation zones of sands washed off by subsurface flow were examined. Vegetation succession was found to modify geocryological conditions in the groundwater discharge area, sometimes leading to its complete freezing. Conditions favorable both for permafrost aggradation and degradation may develop, depending on the landscape type. Ground temperature data indicate that the active layer thickness in sands at a thermal suffosion site covered by sparse pine forest is 3.5 m, while the mean annual permafrost temperature at the depth of zero annual amplitude is –0.2°С. In 2014, a subaerial talik began to form at this site, the bottom of which lowered from 3.5 m down to 6.0 m. At a larch site with tussocks, the active layer thickness is within 0.5–0.8 m and the mean annual permafrost temperature is about –2.0°С. An ERT survey provided information on the current permafrost and groundwater conditions, where groundwater discharge has ceased. A scenario is proposed describing the changes in the discharge area caused by permafrost disturbance above an aquifer. Formation of an underground cavity and collapse of the overlying permafrost layer resulting in characteristic depressions and sinkholes at the surface promote ground freezing in the discharge zone. Mechanical blocking the flow paths reduces the flow velocity promoting the restoration of permafrost and cutting off the area of soil removal by thermal suffosion. Further on, this attenuates the thermal suffosion. Its active phase can shift spatially due to thawing the pore ice in the permafrost in contact with the confined aquifer, widening soil voids and forming new flow pathways. Thus, attenuation of thermal suffosion on the Bestyakh Terrace of the Lena River results from the combination of internal (impeded flow) and external (vegetation succession) factors.
MODELING OF PORE WATER PRESSURE IN FREEZING DISPERSED SOILS DURING MOISTURE MIGRATION
Authors: Bicheng Zhou , Brushkov A. V. , JiaBo Hu
Published: April 2024

Frost heaving of soils is the main cause of engineering accidents in cold regions, but the current experimental as well as numerical studies focus on frost heaving deformation of soils, while there are fewer numerical studies on the main factors causing frost heaving deformation: pore water pressure. In this study, new calculation formulas of pore water pressure for saturated frozen soil are obtained by solving Gibbs free energy equation, and a thermo-hydraulic coupling model under different boundary conditions is constructed to calculate the pore water pressure values and water flow during water migration process. The results showed: (1) the pore water pressure of freezing soil with the ice lens is about ten times that without the ice lens, and the calculated results agree with the previous known experimental results; (2) The temperature of the cold end directly determines the upper limit of the pore water pressure value of freezing soil; (3) Pore water pressure decreases with depth much faster than the rate of temperature decrease.
USING A NEURAL NETWORK TO IDENTIFY TERRITORIES AT RISK OF NATURAL EMERGENCIES
Authors: Vadachkoria O. A.
Published: April 2024

A digital model has been developed on the basis of a set of geological, engineering geological and digital terrain maps for machine learning of a neural network using the content of a map of natural processes for the Sochi territory. The description of natural processes in the preparation of input data for neural network training is based on the results of research on the Southern slope of the Greater Caucasus ridge. The neural network is based on the input and hidden matrices that distribute the input training signal at the output into the constituent elements of events with acceptable accuracy achieved during training. The author has developed his own library with functions that implement the development of a neural network, which has expanded the possibilities for solving target tasks. A set of programs has been created to work with the neural network. The territories of possible manifestations of landslide processes constructed by the neural network are well correlated with the available landslide maps and areas of identified deformations of engineering structures. The completed work can become a convenient tool for developers of territorial planning documents in the functional zoning of the territory.
CORTISOL LEVEL AND Na+/K+-ATPASE ACTIVITY DURING GROWTH AND DEVELOPMENT OF JUVENILE DAUBED SHANNY LEPTOCLINUS MACULATUS (FRIES, 1838) IN THE ARCTIC
Authors: Rendakov N. L. , Kaivarainen E. I. , Pekkoeva S. N. , Murzina S. A. , Nikerova K. M.
Published: April 2024

The dynamics of cortisol level and Na+/K+-ATPase (NKA) activity that are associated with the maintenance of cell ion homeostasis was studied in skeletal muscles of juvenile circumpolar fish daubed shanny Leptoclinus maculatus (Fries, 1838), an ecologically significant representative of the ichthyofauna of the Arctic Svalbard archipelago. It has been established that the level of cortisol and NKA activity decrease during the development of daubed shanny juveniles from L2 stage pelagic juveniles of L5 stage, which are mainly demersal. The results obtained suggest that cortisol may be involved in the regulation of the activity of one of the main osmoregulatory factors, NKA. This may be important for the growth and adaptation of pelagic juveniles of daubed shanny to the demersal habitat during postembryonic development in the Arctic.
APPLICATION OF BIOMARKER FATTY ACIDS OF ROE AND FILLETS TO DETERMINE THE ORIGIN OF STERLET (ACIPENSER RUTHENUS, LINNAEUS, 1758)
Authors: Rudchenko A. E. , Chuprov S. M. , Sushchik N. N.
Published: April 2024

Significant differences were found in the fatty acid composition of roe and muscle tissue (fillet) of starlet (Acipenser ruthenus, Linnaeus, 1758) from Yenisei River and aquaculture farms associated with different food sources. Roe and muscle tissue of sterlet from the natural habitat were characterized by significantly higher levels of fatty acids – biomarkers of diatoms and bacterial matter. Sterlet grown in aquaculture conditions had in the composition of fatty acids significantly higher percentages of oleic and linoleic acids, as well as fatty acids, biomarkers of marine copepods. For the first time, it was proposed to use the calculation of the ratio of the percentage of several biomarker fatty acids and set threshold values for determining the origin of sturgeon roe and fillet from the natural habitat and aquaculture.
THE LIFETIME OF COLOUR MORPHS IN THE POLYMORPHIC POPULATIONS OF THE MOLE VOLE AND THE HYPOTHESIS OF ADAPTIVE POLYMORPHISM
Authors: Vasil’ev A. G. , Bol’shakov V. N. , Vasil’eva I. A. , Sineva N. V.
Published: April 2024

For the first time, different lifetime was established in representatives of three colour morphs (brown, bicolor, black) in 10 populations of the Mole Vole of the Volga region, the Urals and the Trans-Urals. With the longest life span of the species – 5 years, numerically dominant morphs in the population are able to live 1–4 years longer than the accompanying ones. Spearman’s correlation coefficient between the longest life span of morphs and their proportion in the population was Rsp = 0.81. A number of morphofunctional features of colour morphs have been identified. The results obtained have general biological significance, confirming the hypothesis of adaptive polymorphism, and allowing us to evaluate the evolutionary and ecological mechanisms of the formation of selective advantages of morphs (as probable ecomorphs), using them as a natural model of the initial stage of sympatric formation in different parts of the range.
NON-CATALYTIC DOMAINS OF DNA POLYMERASE λ: INFLUENCE ON ENZYME ACTIVITY AND ITS REGULATION
Authors: Maltseva Ekaterina A. , Rechkunova Nadejda I. , Lavrik Olga. I.
Published: April 2024

DNA polymerase λ (Polλ) belongs to the same structural X-family as DNA polymerase β, the main polymerase of base excision repair. The role of Polλ in this process remains not fully understood. A significant difference between the two DNA polymerases is the presence of an extended non-catalytic N-terminal region in the Polλ structure. The influence of this region on the interaction of Polλ with DNA and multifunctional proteins, poly(ADP-ribose)polymerase 1 (PARP1) and replication protein A (RPA), was studied in detail for the first time. The data obtained suggest that non-catalytic Polλ domains play a suppressor role both in relation to the polymerase activity of the enzyme and in interaction with DNA and PARP1.
SYNTHETIC PEPTIDE FRAGMENTS OF THE TOXIN WTX REDUCE BLOOD PRESSURE IN RATS UNDER GENERAL ANESTHESIA
Authors: Severyukhina M. S. , Ismailova A. M. , Shaykhutdinova E. R. , Dyachenko I. A. , Egorova N. S. , Murashev A. N. , Tsetlin V. I. , Utkin Yu. N.
Published: April 2024

Previously, it was shown that the non-conventional toxin WTX from the venom of the cobra Naja kaouthia, when administered intravenously, caused a decrease in blood pressure (BP) and an increase in heart rate (HR) in rats (Ogay et al., 2005). To identify the site of the toxin molecule responsible for these effects, we studied the influence of synthetic peptide fragments of the WTX on BP and HR in normotensive male Sprague Dawley rats under general anesthesia induced by Telazol and Xylazine. It was found that peptides corresponding to the WTX central polypeptide loop, stabilized by a disulfide bond, at intravenous injection at concentrations from 0.1 to 1.0 mg/ml caused a dose-dependent decrease in BP, the HR increasing only in the first 5–10 minutes after administration. Thus, WTX fragments corresponding to the central polypeptide loop reproduce the decrease in blood pressure caused by the toxin.
DENTAL ANOMALY IN HAPALODECTES DUX (HAPALODECTIDAE, MESONYCHIA) FROM THE LATE PALEOCENE OF MONGOLIA
Authors: Lopatin A. V.
Published: April 2024

The holotype of Hapalodectes dux Lopatin, 2001 from the Upper Paleocene of Mongolia (Tsagan-Khushu locality, Naran Bulak Formation, Zhigden Member) is a lower jaw with complete dentition, showing healed alveoli in place of the right P3. Examination of the holotype using X-ray microtomography revealed a rare dental anomaly previously unknown in fossil mammals, namely the presence of the inverted (positioned upside down and rotated lingual side labially) impacted premolar inside the dentary. The cause of this anomaly may be an aberration of a tooth bud location or an injury.
ENVIRONMENTS IN THE CENTRAL NORWEGIAN-GREENLAND BASIN DURING NEGLACIATION IN THE LAST 5 THOUSAND YEARS
Authors: Matul A. G. , Kazarina G. Kh.
Published: April 2024

A comparison of the new results on diatom micropaleontology with the available paleooceanological data on core PS1243-2 and global/regional paleoclimate archives made it possible to assume that neoglaciation in the central Norwegian-Greenland Basin near the Arctic front began no later than 4500 years ago. From this level, the Arctic front gradually approached the study area. There was a decrease in the influence of the mixed Arctic-Norwegian water, and the conditions on the surface became more contrasting, with an increase in signs of Arctic or North Atlantic (from the Norwegian Current) water. The moments of the greatest contrast are noted during short-term warmings of the Late Holocene.
PHYSICO-CHEMICAL CONDITIONS FOR THE FORMATION OF PRODUCTIVE MINERAL ASSOCIATIONS OF GOLD DEPOSITS OF THE TAIMYR-NORTH EARTH ORGEN
Authors: Borovikov A. A. , Proskurnin V. F. , Palyanova G. A. , Petrov O. V. , Bortnikov N. S.
Published: April 2024

For the first time, based on the data of the study of fluid inclusions, the PTX parameters of the formation of gold mineralization of the Taimyr-Severozemelsky orogen were established. The temperature of formation of gold ores covers the range from 310 to 105°C, the pressure was not lower than 110–96 MPa. The ore-forming fluids were characterized by NaCl + KCl + H2O + CO2 + CH4 + N2 composition and salinity up to 9.7 wt. % in equiv. NaCl. The composition of native gold (fineness varies from 960 to 550‰) and minerals of productive mineral associations has been determined. Ore-forming fluids of gold-sulfide-quartz ore occurrences of the accretionary Schrenk-Fadeevskaya zone (Yasnenskoye and Malinovskoye in North-East Taimyr) are more oxidized and less saline compared to the gold-quartz occurrences of the orogenic type of the Mininsko-Bolshevitskaya myogeoclinal zone (Nizhnelitkenskoye, Vidimoe, Nerpichye).
NEOTECTONIC DISLOCATIONS AT THE BARENTS SEA SHELF AND THEIR GENESIS ACCORDING TO THE MORPHOMETRY OF BATHYMETRY, SEISMIC SECTIONS AND THE DEEP MANTLE STRUCTURE
Authors: Sokolov S. Yu. , Abramova A. S. , Shkarubo S. I.
Published: April 2024

The paper provides a comprehensive analysis of the morphometric attribute “general curvature” for the bathymetry of the Barents Sea, seismic and seismoacoustic data containing in the wave field patterns tectonic faults emerging to the surface, a fault network of the sedimentary cover confirmed by seismic surveys, and seismotomographic data showing the heterogeneous deep structure by the distribution of seismic wave velocities in the upper mantle. The analysis of these data showed the presence of a causal relation between rheologically heterogeneous and mobile blocks of the upper mantle and the crystalline part of the Earth’s crust with the deep fault network, emerging on the bottom surface and being a relief-forming factor that forms characteristic domains with different textures performed by the morphometric attribute “general curvature”.
ANOMALOUS SEISMIC NOISES FROM THE DECEMBER 9, 2020 MW = 5.6 KUDARA EARTHQUAKE IN THE BAIKAL BASIN
Authors: Dobrynina A. A. , Sankov V. A. , Bornyakov S. A. , Korol S. A. , Sankov A. V.
Published: April 2024

Studies have been conducted on the variations of ambient noise recorded by broadband and short-period seismic stations in the area of South Baikal before and after the large December 9, 2020 Kudara earthquake with Mw = 5.6. 10 days before the earthquake, there was a gradual increase of oscillation amplitudes in the frequency range from 0.01 to 0.1 Hz, with an increasing background observed also during 4 days after the main shock (period from 01.12.2020 to 13.01.2021). The maximum amplitude increase is 19.5 against the background. During this time, there were recorded 48 aftershocks. The analysis of direction of particle motion in seismic waves over the reporting period showed an abrupt change in the orientation of oscillations, which is fully consistent with the azimuth for the main shock epicenter. The analysis of seismograms over the next period (from December 13) did not show similar effects in the ambient noise field. Apparently, the ambient noise field reflected the process of slow faulting before the earthquake and after the main shock with subsequent attenuation.
TRACE ELEMENT COMPOSITION OF THE WATERS OF THE KOLYMA RIVER MOUTH SECTION
Authors: Savenko A. V. , Savenko V. S. , Efimov V. A. , Pokrovsky O. S.
Published: April 2024

The content of ions of the main salt composition and 50 dissolved trace elements (Li, Rb, Cs, Be, Sr, Ba, Mn, Fe, Co, Ni, Cu, Zn, Cd, Tl, Pb, Al, Sc, Ga, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ti, Zr, Hf, Th, U, F, B, Si, Ge, P, V, As, Sb, Cr, Se, Mo, W) in the waters of the Kolyma River mouth section the spring–summer flood decline and on the summer–autumn period was determined. A close positive correlation was established between the dissolved trace elements concentrations in the waters of the Kolyma River and of the rivers in the White and Kara seas catchment areas. Differences in the concentrations of dissolved trace elements in the river waters of the Russian Arctic are generally proportional to the ratio of their mineralization values.
EDIACARA-TYPE BIOTA IN THE UPPER PRECAMBRIAN OF TIMAN RANGE (DZHEZHIM-PARMA HILL, THE KOMI REPUBLIC)
Authors: Kolesnikov A. V. , Latysheva I. V. , Shatsillo A. V. , Kuznetsov N. B. , Kolesnikov A. S. , Desiatkin V. D. , Romanyuk T. V.
Published: April 2024

The macroscopic fossils, an Ediacara-type composite moulds and casts, were found in the Dzhezhim Formation of the Timan Range for the first time. Among them, the representatives of palaeopascichnids, frondomorphs, chuariomorph colonies, arumberiamorph structures as well as trace fossils were diagnosed. Finding of a large number of various Ediacaran fossils on Timan Range both develops the understanding of their palaeogeographic range, and also clarifies the age limits of the deposition of the Dzhezhim Formation, whose stratigraphic position in the Upper Precambrian section was controversial.
ABOUT SOME PROBLEMS AND SOLUTIONS IN 3D MODELING OF OIL AND GAS FIELD DEVELOPMENT PROCESSES
Authors: Zakirov E. S.
Published: April 2024

The article discusses the existing problems and original author’s solutions to the problems of 3D computer modeling of the processes of development of natural hydrocarbon deposits. The transition from laboratory experiments, 3D geological modeling to the creation of 3D filtration models of the reservoir, their subsequent adaptation to the actual data of the development history is considered. The use of a refined 3D model to optimize the economic performance of the operation of the developed field is discussed. In fact, the approach to the unpopulated management of oil and gas field development using a constantly adapting 3D model of the reservoir is justified.
SULFIDE SULFUR ISOTOPE SOURCES OF THE NEOARCHEAN IRON ORE DEPOSITS IN THE KOSTOMUKSHA GREENSTONE BELT, KARELIA (RUSSIA)
Authors: Vysotskiy S. V. , Khanchuk A. I. , Velivetskaya T. A. , Ignatiev A. V. , Aseeva A. V. , Nesterova N. S.
Published: April 2024

In this paper we provide primary data on multi-isotope sulfur composition of the Neoarchean BIF sulfides of the Kostomuksha greenstone belt in Karelia (the Karelian Craton on Fennoscandian Shield). These sulfides formed at 2760–2740 Ma. Pyrite associated with fine-grained magnetite showed negative δ34S values (up to –7.8‰) and positive Δ33S values (up to +0.7‰). At the same time, pyrrhotite of vein-disseminated ores associated with shale demonstrated both negative δ34S (up to –6‰), and Δ33S values (up to –0.46‰). Based on the obtained data we assume that sulfur for the BIF sulfides was transported from three reservoirs: - atmospheric (photolytic), hydrospheric (seawater sulfate), and magmatogenic. Sulfur isotope ratios in sulfides preserved the evidence of interaction between abiological (atmospheric, hydrothermal) and biological processes (dissimilatory microbial reduction) that occurred during the formation of iron ore deposits of the Kostomuksha greenstone belt in Karelia.
NEW GEOCHRONOLOGICAL AND ISOTOPE DATA ON MESOZOIC GRANITOIDS OF EASTERN TRANSBAIKALIA
Authors: Naryzhnova A. V. , Khromykh S. V. , Kruk N. N. , Kotler P. D.
Published: April 2024

Eastern Transbaikalia is a unique rare-metal province of Russia. Most of the studied deposits are associated with granitoid intrusions. Despite the high degree of knowledge of regional magmatism, a number of questions remain related to both the belonging of specific massifs to magmatic complexes and the correlation of certain complexes within various structural-formation zones. This paper compares the material composition and age of several petrotypical and parapetrotypical massifs classified as Late Mesozoic complexes distributed within the Aginskaya, Prishilkinskaya, and Argunskaya structural-formational zones of Eastern Transbaikalia. Based on the results of U-Pb dating, two stages of granitoid magmatism have been established: 1) the end of the Middle – the beginning of the Late Jurassic (163–156 million years ago) and 2) the beginning of the Early Cretaceous (142 million years ago). It is shown that the closely aged rocks of the Borshchovochny, Amudzhikano-Sretensky and Shakhtama complexes have similar material characteristics, while the rocks of the Kukulbey complex (from three massifs) vary in composition. Elevated δ18O values (from +10.8‰ to +11.9 ‰) for the rocks of the Jurassic complexes indicate their formation mainly due to the melting of crustal material, and lower δ18O values (from +9.8 ‰ up to +10.3‰) for the Early Cretaceous granitoids suggest the contribution of a mantle source to their genesis.
STRUCTURE OF THE EARTH’S CRUST OF THE LAPTEV SEA CONTINENTAL MARGIN AND THE ADJACENT PART OF THE EURASIAN BASIN
Authors: Piskarev A. L. , Kaminsky V. D. , Poselov V. A. , Bezumov D. V. , Zholondz S. M. , Kireev A. A. , Ovanesian G. I. , Savin V. A. , Smirnov O. E.
Published: April 2024

A 3D model of the Earth’s crust for the Laptev Sea continental margin and the adjacent part of the Eurasian Basin was built using the latest seismic and gravity data. The thickness of the Earth’s crust in the research area equals 7–11 km, which corresponds to a highly extended continental or oceanic crust. Basement formation and sedimentation in this area most likely began in the Late Jurassic. The south-eastern part of the Eurasian Basin is separated from the rest of the basin by a dextral shear zone, the displacement along which during the Paleogene was more than 100 km.
RUNOFF FORMATION SETTINGS: MULTIFACETED RESEARCH IN TESTBED CATCHMENTS (THE USSURI R. HEADWATERS)
Authors: Gartsman B. I. , Shamov V. V. , Gubareva T. S. , Lupakov S. Yu. , Kozhevnikova N. K. , Bugaets A. N. , Bodeskul A. G. , Lutsenko T. N. , Pshenichnikova N. F. , Gonchukov L. V.
Published: April 2024

The results of long-term field studies on small watersheds in the upper reaches of the Ussuri River (Primorsky Krai, Russia) are presented. In virtue of modern observation means, a unique dataset was obtained to effectively reflect the complicated processes of runoff formation in small low-mountain river basins. The tools of geochemical and hydrological modeling were jointly used to describe the watersheds’ behavior, and an assessment of the genetic components of the river flow was carried out, that made it possible to deeper research the processes and settings of runoff formation, and to evaluate the factors determining the accuracy of runoff modeling.
ENERGY OF TORNADOES AND LANDSPOUTS
Authors: Golitsyn G. S. , Chernokulsky A. V. , Vazaeva N. V.
Published: April 2024

According to the data on the sizes and intensity of tornadoes and landspouts, their characteristic times and forcings are found. Depending on the intensity, the average times vary by a factor of 3 and the forcings by a factor of 6. The energy of the vortices has been estimated and is expressed, among other things, in TNT equivalent mass units.
NEW DATA ON THE AGE OF MAGMATIC ROCKS OF THE ALPHA-MENDELEEV RISE (ARCTIC OCEAN): RESULTS OF ISOTOPIC U/Pb DATING OF ZIRCONS
Authors: Skolotnev S. G. , Fedonkin M. A. , Korniychuk A. V.
Published: April 2024

The age of magmatic rocks of the basic composition sampled at the Alpha-Mendeleev Rise in the Arctic Ocean with the help of a research submarine was studied, based on the measurement of the U/Pb age of zircons separated from them. Early Cretaceous rocks of the moderately alkaline series, formed at the turn of 112 million years, are most common on the Rise. These rocks contain a large number of ancient xenogenic zircons, the age analysis of which shows that the subalkaline melts interacted with the crust at two levels: with the horizon of Early Cretaceous sandstones and with rocks of the Late Archean crystalline basement with an age of 2675.1 ± 11.6 million years. They also contain a small number of younger zircons with an age of 83–87 million years, which probably arose during the recrystallization of Early Cretaceous zircons under the influence of Late Cretaceous magmatism.
EVIDENSE OF RICE CULTIVATION IN THE PRIMORYE IN MIDDLE AGE
Authors: Razzhigaeva N. G. , Ganzey L. A. , Grebennikova T. A. , Prokopets S. D. , Moreva O. L. , Poperechny D. M.
Published: April 2024

The layer of displaced paleosol was found in a section under a rampart in the South Ussuriysk Fortress, that was presumably used for rice farming. The paleosol was periodically flooded, as evidenced by the presence of diatoms of different ecologies. Buliform rice phytoliths were found in the paleosol. A series of radiocarbon dates was obtained, that made it possible to restore the chronology of events. Finding of cryptotephra B-Tm of the Baitoushan (946/947 CE) made it possible to determine that the rice field existed in the period between the middle of the 10th century and the construction of the fortress at the beginning of the 12th century. The soil was transferred from the floodplain where soil profiles formed in the Middle-Late Holocene under drier conditions than in the Middle Ages. The moisture increase in the Medieval Warm Period was favorable for the development of agriculture, including rice cultivation. The deposits formed during severe floods overlapped both the cultural layers and the paleosol of the rice field. Perhaps this was one of the reasons for cessation of rice cultivation along with climate change towards cooling and a decrease in precipitation.
POST-TECTOGENIC EVENTS AND EXHUMATION PROCESSES IN SVEKOKARELIDES OF THE LADOGA REGION
Authors: Morozov Yu. A. , Matveev M. A. , Smulskaya A. I. , Kulakovsky A. L.
Published: April 2024

Elements of the structure of the Svecokarelian pericratonic zone of the Karelian Massif (SE Fennoscandia), formed after the main events of the Svekofennian tectogenesis, have been identified and characterized. Dated age intervals of the orogenic stage and post-orogenic extensional collapse manifestation, determined the depth levels of the corresponding structures and visualized the scheme of differentiated exhumation of the deep complexes of the post-Proterozoic Savo-Ladoga movable zone. Approximate estimations of exhumation rates of deep material at certain stages of the Precambrian evolution of this zone are given.
EQUILIBRIUM FORMS OF AN INITIALLY CURVED BERNOULLI–EULER BEAM IN ELECTRIC AND THERMAL FIELDS
Authors: Morozov N. F. , Indeitsev D. A. , Mozhgova N. V. , Lukin A. V. , Popov I. A.
Published: April 2024

On the basis of a geometrically nonlinear model of a Bernoulli-Euler beam, the influence of the amplitude and shape of the initial curvature on the nature and stability of the static equilibrium positions of the system under conditions of electrostatic and thermal effects has been studied. With the help of numerical methods of the theory of bifurcations, a complete parametric analysis of the diagrams of evolution of equilibrium positions for beams with initial curvature in terms of symmetric and asymmetric lower modes of free vibrations is performed. The regions in the parameter space of the values of the axial force of a mechanical or temperature nature and the strength of the electrostatic field, in which the elastic system has the property of bistability, are determined. The prospect of using the considered class of structures with projected geometry perturbations as sensitive elements of high-precision microelectromechanical sensors of various physical quantities is noted.
SUPER-SENSITIVE REGISTRATION OF POLYFUNCTIONAL MAGNETIC NANOMATERIALS FOR THE RAPID DETERMINATION OF MOLECULAR MARKERS OF DISEASES
Authors: Orlov A. V. , Malkerov Yu. A. , Skirda A. M. , Novichikhin D. O. , Znoyko S. L. , Bragina V. A. , Nikitin P. I.
Published: April 2024

Magnetic particles (MPs) based on superparamagnetic iron oxide nanocrystals are increasingly used in modern research for the development of express technologies for high-precision determination of the concentration of biomolecules. In this work, we developed a universal method for using MPs as polyfunctional agents that perform several different functions in one analysis for topical issues of biochemical and medical diagnostics, based on the original technology of ultrasensitive detection of nonlinear magnetic nanomaterials. The method was tested for the rapid quantitative registration of cardiac markers and SARS-CoV-2-associated molecular markers in complex matrices. The proposed method is promising for creating test systems for prehospital monitoring, particularly for emergency molecular diagnostics in patients with suspected acute myocardial infarction, as well as for the rapid detection of coronavirus infection.
VECTOR S-PARAMETRIC ANALYSIS OF SIGNAL PHASE DYNAMIC RADIO IMAGES
Authors: Shadinov S. S. , Kostin M. S. , Konyashkin G. V. , Korchagin A. S. , Romanovsky M. Yu. , Guseyn-zade N. G.
Published: April 2024

A vector method for recording phase-dynamic radio images is proposed by forming and numerically analyzing the S-parametric scattering matrix of multidisciplinary signatures of material media and objects. The key advantages of aperture capture of signal radio images by the method of frequency-synthesized power spectral density function of a scattered wave radio profile are determined. On the basis of a vector analyzer of microwave circuits and broadband antennas of the Vivaldi type, an experimental laboratory installation for signal registration of time-scale radio images in the spectral region of 0.03…6.0 GHz has been built. The dependences of the influence of the angular characteristics of the object on the spectral-temporal structure of the formation of phase-dynamic radio images have been experimentally established. As a time-scale postprocessing of radio images, a method of cepstral transformation of S-parametric characteristics with convolution of basic signatures in the radiogenic of the irradiated object is proposed. A series of cepstral convolutions of phase-dynamic radio images was obtained, establishing a functional relationship between the change of the signature of an object in time with its radio genome.
NEW MARKERS FOR DETERMINATION OF CAROTENOID MOLECULES ISOMERISM USING RAMAN SPECTROSCOPY
Authors: Vasimov D. D. , Ashikhmin A. A. , Bolshakov M. A. , Moskovskiy M. N. , Gudkov S. V. , Yanykin D. V. , Novikov V. S.
Published: April 2024

The paper presents an analysis of the experimental and calculated Raman spectra of plant and bacterial carotenoids: neurosporin, spheroiden, lycopene, spirilloxanthin, β-carotene, lutein, ζ-carotene, α-carotene and γ-carotene. A number of characteristic features in the Raman spectra of carotenoids are described for the first time, which make it possible to determine the structure of end groups of molecules and to distinguish their isomers.
GENERATION OF RECTANGULAR NANOSECOND ELECTROMAGNETIC PULSES WITH A PICOSECONDS RISE FRONT
Authors: Garnov Corresponding Member of the RAS S. V. , Bulgakova V. V. , Dolmatov T. V. , Ushakov A. A. , Bukin V. V.
Published: April 2024

A method for generation of ultra-wideband electromagnetic pulses with a nanosecond duration and a picosecond rise time has been studied. The emitter is a horn antenna with a photoconductive switch irradiated by laser pulses. It has been shown that the duration of ultra-wideband electromagnetic pulses is determined by the length of the antenna and the semiconductor material, and the rising front is determined by the front of the laser pulses used to initiate the photoconductive switch. The work shows typical pulse durations of ~1 ns with a rising edge of up to ~34 ps.
A NEW BIODEGRADABLE PROMOTER OF METHANE HYDRATE FORMATION
Authors: Mel’nikov V. P. , Molokitina N. S. , Drachuk A. O. , Pletneva K. A. , Kibkalo A. A. , Grigor’ev B. V. , Pandey G.
Published: April 2024

The course of active development of the Arctic zone of the Russian Federation by companies of the fuel and energy complex implies the development of new methods and approaches to storage and transportation of natural gas in order to reduce the negative impact on the ecosystems of cold regions while maintaining the economic feasibility of its use. This paper proposes a method for optimising the technology of transporting and storing natural gas in the form of gas hydrates using soya lecithin as a promoting additive. Experimental methods show that soya lecithin additive at a concentration of 0.5 wt. % is not inferior to the most effective hydrate formation promoter – sodium dodecyl sulphate at a concentration of 0.1 wt. %. However, a comparison of the environmental characteristics shows a clear advantage for soya lecithin. It is also shown that the synthesis of methane hydrate from ground frozen solutions of soya lecithin is at least three times faster than from liquid solutions.
AMINO DERIVATIVES OF ACRIDINE: SYNTHESIS, STUDY OF ANTICHOLINESTERASE AND ANTIOXIDANT ACTIVITIES
Authors: Shchepochkin A. V. , Uglova A. F. , Utepova I. A. , Gradoblyanskaya E. S. , Averkov M. A. , Kovaleva N. V. , Rudakova E. V. , Boltneva N. P. , Serebryakova O. G. , Makhaeva G. F. , Charushin V. N. , Chupakhin O. N.
Published: April 2024

A simple and accessible approach to the synthesis of new amine derivatives of acridine based on the direct C–H functionalization methodology was developed. The inhibitory effect of the synthesized compounds on cholinesterases and carboxylesterases, as well as their antioxidant activity, was studied. A moderate inhibition of BChE by the morpholine and pyrazole derivatives of acridine and a high anti-BChE activity of the N-methyl-piperazine one were shown.
THE SKIES ARE FALLING: MATHEMATICS FOR NON-MATHEMATICIANS
Authors: Vavilov N. A. , Khalin V. G. , Yurkov A. V.
Published: April 2024

Mathematical education, both mass education, and university education of non-mathematicians, are in an abominable state, and rapidly degrading. We argue that the instruction of non-mathematicians should be dramatically reformed both as substance and style. With traditional approach, such a transformation would take decades, with unclear results. But we do not have this time. The advent of Computer Algebra Systems gives the mathematics community a chance to reverse the trend. We should make a serious attempt to seize this opportunity. In the present paper we describe one such project of reform implemented at the St Petersburg State University.
ELEMENTARY INVARIANTS FOR QUANTIFIED PROBABILITY LOGIC
Authors: Speranski S. O.
Published: April 2024

Let QPL be the two-sorted probabilistic language proposed in [8], which expands the well-known ‘polynomial’ language described in [3, Section 6] by adding quantifiers over events. We show that all atomless spaces have the same QPL-theory, and this theory is decidable. Also we introduce the notion of elementary invariant for QPL and use it for obtaining exact complexity upper bounds for some interesting probabilistic theories.
EXISTENCE AND RELAXATION OF SOLUTIONS FOR A DIFFERENTIAL INCLUSION WITH MAXIMAL MONOTONE OPERATORS AND PERTURBATIONS
Authors: Tolstonogov A. A.
Published: April 2024

A differential inclusion with a time-dependent maximal monotone operator and a perturbation is studied in a separable Hilbert space. The perturbation is the sum of a time-dependent single-valued operator and a multivalued mapping with closed nonconvex values. A particular feature of the single-valued operator is that its sum its with the identity operator multiplied by a positive square-integrable function is a monotone operator. The multivalued mapping is Lipschitz continuous with respect to the phase variable. We prove the existence of a solution and the density in the corresponding topology of the solution set of the initial inclusion in the solution set of the inclusion with the convexified multivalued mapping. For these purposes, new distances between maximal monotone operators are introduced.
ON SUBSPACES OF AN ORLICZ SPACE SPANNED BY INDEPENDENT IDENTICALLY DISTRIBUTED FUNCTIONS
Authors: Astashkin S. V.
Published: April 2024

Subspaces of an Orlicz space LM generated by probabilistically independent copies of a function \(f \in {{L}_{M}}\), \(\int_0^1 {f(t){\kern 1pt} dt} = 0\), are studied. In terms of dilations of f, we get a characterization of strongly embedded subspaces of this type and obtain conditions that guarantee that the unit ball of such a subspace has equi-absolutely continuous norms in LM. A class of Orlicz spaces such that for all subspaces generated by independent identically distributed functions these properties are equivalent and can be characterized by Matuszewska–Orlicz indices is determined.
STUDY OF VOLTERRA INTEGRO-DIFFERENTIAL EQUATIONS BY METHODS OF SEMIGROUP THEORY
Authors: Rautian N. A.
Published: April 2024

The abstract Volterra integro-differential equations are investigated, which are operator models of problems of viscoelasticity theory. The class of equations under consideration also includes the Gurtin-Pipkin integro-differential equations describing the process of heat propagation in media with memory. The sums of decreasing exponents or sums of Rabotnov functions with positive coefficients can be considered in particular as the kernels of integral operators, which are widely used in the theory of viscoelasticity and heat propagation theory.