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The paper summarizes data on the historical activity of Ivan Grozny volcano (Iturup Island, Kuril Islands), including the results of original studies of sulfur hydrothermal and eruptive activities of the volcano since 2004. New chemical data on the volcanic edifice rocks and pyroclastics of the last explosive eruption in 2012–2013 are presented. The composition of the volcanic edifice rocks varies from andesites to dacitic andesites (58.16–61.42 wt % SiO2) of the medium potassium series (0.93–1.14 wt % K2O). Pyroclastics from the 2012–2013 explosive eruption chemically correspond to andesites (57.20–59.54 wt % SiO2) with moderate potassium contents (0.95–1.05 wt % K2O). According to microprobe studies, glasses have much more felsic compositions. The values obtained are similar to the geochemical compositions of the products of the 1973 and 1989 eruptions. Taking into account the dominant wind regime in central Iturup Island, the hazard from ashfalls from future eruptions of Ivan Grozny volcano is estimated, indicating the predominant ash spread in the northwestern, western, and southwestern directions. [ABSTRACT FROM AUTHOR]

We review 61 papers devoted to stellar magnetism and published in 2023. The main interest of researchers is focused on the search for new magnetic stars, monitoring the magnetic fields of CP stars and other types of objects. Interest in the study of radio and X-ray emission from magnetic stars has increased. Most of the new data are based on the Gaia astrometry, TESS, and Kepler photometry, and LAMOST low-resolution spectroscopy. [ABSTRACT FROM AUTHOR]

We continue the annual publications of the magnetic field measurements of chemically peculiar stars. Observations were carried out with the Main Stellar Spectrograph of the 6-m telescope at SAO RAS in 2016. We obtained 108 pairs of circularly polarized spectra for 64 stars. For five objects (HD 9050, HD 31592, HD 82093, HD 142502, and HD 190068), a magnetic field was discovered for the first time. We estimated the physical parameters (effective temperature , surface gravity , projected rotation velocity ) and the radial velocity for all the objects. [ABSTRACT FROM AUTHOR]

We establish exact order estimates for the approximations of the Sobolev classes W p , α r T d of periodic functions of numerous variables with bounded dominating mixed derivative. The approximations are performed by using trigonometric polynomials with spectra in step hyperbolic crosses, and the errors are estimated in the metric of the space B q , 1 T d , 1 ≤ p, q < ∞. [ABSTRACT FROM AUTHOR]

CLE (CLAVATA3/ENDOSPERM SURROUNDING REGION-related) peptides are systemic regulators of legume-rhizobium symbiosis that negatively control the number of nitrogen-fixing nodules. In Medicago truncatula, the expression of the MtCLE35 gene is activated in response to rhizobial inoculation and nitrate treatment, and its overexpression systemically inhibits nodulation. However, little is known about the molecular mechanisms underlying MtCLE35-mediated inhibition of nodulation. In order to elucidate target genes regulated by the MtCLE35-induced signaling cascade, we analyzed the transcriptome of MtCLE35-overexpressing roots inoculated by rhizobia using MACE (Massive Analysis of cDNA Ends) sequencing. Totally, 1390 genes were found to be differentially expressed between MtCLE35-overexpressing (35S::MtCLE35) and control (35S::GUS) roots after rhizobial inoculation, among them 268 genes were upregulated and 1122 genes were downregulated. Among downregulated genes, many known regulators of legume-rhizobia symbiosis were found. Genes upregulated in rhizobia-inoculated MtCLE35-overexpressing roots included ones associated with defense response and cellular redox status. Furthermore, stable transgenic plants overexpressing the MtCLE35 gene were obtained in this study, and gene expression qPCR analysis of selected differentially expressed genes in rhizobia-inoculated roots was performed in such plants. Collectively, our data suggest that overexpression of the MtCLE35 gene prevents the induction of nodulation program, which is accompanied by the expression of defense-related gene in MtCLE35-overexpressing rhizobia-inoculated M. truncatula roots. [ABSTRACT FROM AUTHOR]

The Rb–Sr age of glauconite and the U–Pb LA-ICP-MS age of detrital zircons from sandstones of the Riphean Okos Formation and the Vendian Ust-Pinega Formation were determined in the Keltmen-1 parametric borehole, drilled in the Vychegda trough of the Mezen syneclise in the northern part of European Russia. The model Rb–Sr age of glauconite (870–820 Ma) and the U–Pb age of the youngest detrital zircon (1005 ± 14 Ma) limit the time of accumulation of the Okos Formation to the first half of the Late Riphean, which is in good agreement with the biostratigraphic data available. The U–Pb age of the youngest detrital zircon from the lower part of the Ust-Pinega Formation suggests that accumulation of Late Vendian sandstones into the Mezen Basin began about 575 Ma. Thus, the duration of the stratigraphic hiatus between the Riphean and Vendian is estimated to be about 250–300 Ma. In the Late Riphean and Late Vendian, the Mezen basin was filled with terrigenous material of Archean–Late Proterozoic age (from 3.25 to 1.02 Ga), the sources of which were rocks of the Baltic Shield. In the lower part of the Ust-Pinega Formation, a population of detrital zircon of Vendian age (730–575 Ma) was discovered, a possible source of which could have been rocks of the Proto-Ural–Timan Orogen. [ABSTRACT FROM AUTHOR]

The complex body-trace fossils of Vendian soft-bodied biota have been found for the first time in the Central Urals during the study of the Vilukha and Sinii Kamen members of the Chernyi Kamen Formation of the Upper Vendian Sylvitsa Group (Kos'va River area, Perm Krai of Russia). These sedimentary sequences were exposed along the valley of the Shirokovskii Reservoir. Among the fossils, the chuariomorpha-like species Beltanelliformis konovalovi, previously described from the Konovalovka Member of the Chernyi Kamen Formation, was identified. However, the morphological analysis of the new fossil material revealed a number of principal differences from representatives of the genus Beltanelliformis Menner, 1974. It was shown that the taxon B. konovalovi, most likely, does not belong to this genus and probably needs further revision, and, in turn, the fossil locality at the Shirokovskii Reservoir allows us to establish a new area with fossils of the Precambrian mobile organisms. [ABSTRACT FROM AUTHOR]

The data of long-term Roshydromet hydrochemical monitoring were used to establish space and time regularities in water quality variations in the Ural River. Trends in variations in the concentrations of various pollutants in river water over the period 1986–2021 were identified. The effect of the interannual and intra-annual dynamics of water flow on water quality was evaluated. It has been shown that there is no strict dependence of river water pollution on water abundance or the season of the year in the Ural River basin. It has been found that the level of river water pollution in both high-water and low-water periods shows a significant influence of point and diffuse pollution sources in different parts of the river network. [ABSTRACT FROM AUTHOR]

A technique to evaluate the degree of roundness of detrital zircons on a 5-point scale based on the preservation of crystal vertices, edges, and faces is presented. Based on measurements in individual grains, the integral roundness index Rs is calculated for a zircon grain set from various stratigraphic units. The obtained data make it possible to determine the proportion of different class grains in various sequences and to assess their similarity/difference degree, which can serve as an additional criterion for the differentiation of sedimentary sections. The proposed method is used to compare the roundness characteristics of detrital zircons from some Cimmeride sedimentary sequences in the Crimean Mountains. It is shown that relative to counterparts in the flysch sequences, sandstones of the Chenka sequence are characterized by a higher proportion of unrounded and weakly rounded zircons and a virtual absence of completely rounded grains. Value of Rs for the zircon grain set ranges from 3.41 and 3.95 for the Tauric Group to 2.55 for the Chenka sequence. Thus, Rs values in the sequences are marked by a significant difference, which is also confirmed by values of the mutual pair coefficient p calculated using the Kolmogorov–Smirnov test. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the effect of molding pressure on the characteristics of radioprotective composites based on polyethylene and boron carbide (B4C). Software simulation is applied to select a temperature range for heating a press mold of a given size. Experiments are performed to determine the required holding time of the composite and identify defects arising from various deviations from the optimal temperature parameters. The strength of samples under various molding pressure conditions is tested, and the optimal pressure is determined. A composite with the following mechanical characteristics under optimal molding conditions is obtained: density () g/cm3, bending strength MPa, and sound velocity in the composite () m/s. [ABSTRACT FROM AUTHOR]

The Antarctic Digital Magnetic Anomaly Project is an international research effort to construct a magnetic map of the continent based on ground, satellite, marine, and aeromagnetic surveys. This paper reports the magnetic mapping of the shelf zone in the SE part of the Wilhelm Archipelago, West Antarctica, based on magnetic surveys conducted with Zodiac boats. A spectacular feature of this area is the strong magnetic anomaly of the Antarctic Peninsula (AP) batholith, which was the product of subduction-related Mesozoic–Cenozoic arc magmatism on the former margin of Western Gondwana. We constructed and analyzed a detailed magnetic map of magnetic field anomalies using field observations of rock exposures on the islands and magnetic properties of rocks from laboratory data. The oldest volcanic rocks of Jurassic to Lower Cretaceous age relate to N-NE trending bands of negative magnetic field. The largest feature in the study area is an Upper Cretaceous/Paleogene granodiorite complex that produces a positive magnetic anomaly. Many smaller anomalies are also present over gabbroid bodies of Cretaceous age. Two-dimensional magnetic modeling shows that heterogeneities in the upper crust may have magnetic susceptibilities in the range of 0.005–0.13 SI. Magnetic field anomalies also delineate an orthogonal system of tectonic faults, including the main NE fault along the Penola Strait (sub-parallel to the AP coastline) and four intersecting faults. These fault systems may be associated with different stages of continental margin evolution along the Antarctic Peninsula. [ABSTRACT FROM AUTHOR]

The first results of U–Th–Pb isotope dating of detrital zircons (dZr) from the Chenka sandstones of the Cimmerides of Mountainous Crimea are presented. Carboniferous–Triassic dZr dominate among dZr from Chenka sandstones. Analysis of previously obtained sets of dZr ages from the age and lithologically different formations of Cimmerides of Mountainous Crimea has revealed certain regularities in the change in the time of the provenance signal and, accordingly, of the provenance areas, whose erosion products compose the studied formations. A comparison of the obtained of U–Pb ages of dZr from Chenka sandstones with similar dates obtained for sandstones from the Upper Triassic–Jurassic formations has shown that the provenance signals of the Chenka sandstones and Upper Triassic–Lower Jurassic flysch strata are different, but the provenance signals of the Chenka sandstones and Middle–Upper Jurassic coarse clastic strata are similar. Detrital zircons from the Chenka sandstones show that the parameters of the Th–U distribution in them are intermediate between those from sandstones of flysch and coarse-grained strata, respectively. In general, the isotope-geochronological and geochemical data we obtained and some features of the internal structure of dZr grains from the Chenka sandstones can be used as a strong argument in favor of considering Chenka sandstones as an independent stratigraphic unit with an age not older than the Middle Jurassic. The similarity of the characteristics of dZr grains from sandstones of the Chenka sandstones with those from Middle–Upper Jurassic sandstones casts doubt on the correlations of the Chenka sandstones with a number of lithologically similar units of the southwestern regions of Mountainous Crimea, specified as Early Jurassic in age based on finds of fossil remains. [ABSTRACT FROM AUTHOR]

Chemically peculiar (CP) stars of early spectral types are the only Main-Sequence objects of the Hertzsprung–Russel diagram that have strong magnetic fields covering the entire surface of a star and maintaining a stable structure on a scale of at least decades. The origin and evolution of magnetic fields of CP stars are still a subject of discussion, despite significant progress in the field of observation of stellar magnetic fields and their theoretical description. This situation has developed not least because of the problem of accurately determining the age of CP stars. We performed a review of magnetic fields of CP stars in the Orion OB1 association and five intermediate-age clusters ( Per, Pleiades, NGC 7092, and IC 4756) and found evidence of a strong decrease in the proportion and strength of magnetic fields of CP stars relative to normal stars of the same spectral types. The found dependences can serve as confirmation of the fossil nature of large-scale magnetic fields of stars. The conclusions of this paper are based on the measurements of more than 800 spectra obtained in the period from 2013 to 2023 with the Main Stellar Spectrograph of the 6-m BTA Telescope for about 100 stars. [ABSTRACT FROM AUTHOR]

The light curves for almost 50 thousand stars with magnitudes have been obtained over 2.5 years at SAO RAS in the process of conducting an exoplanet survey in roughly -sized fields around the white dwarfs WD 0009 501 and GRW 708247. In this paper we present a catalog of variable stars that have been found in the considered regions. Periodogram analysis was used as the main variation search method. The catalog includes 150 periodic variable stars: 113 of them have been known previously, and for the remaining 37 variations have been discovered for the first time. These stars were classified according to the nature of the variations into four eclipsing variable and three pulsating types, as well as rotating stars. We present the periods and variation amplitudes in the range of and , determined from the investigated data. [ABSTRACT FROM AUTHOR]

The first results of the U–Th–Pb isotope dating of detrital zircons (dZr, N = 130, n = 91) from the middle Danian sandstones (63.9–65.3 Ma) of the Cretaceous–Eocene Novorossiisk–Anapa flysch widely developed in the Sochi synclinorium (southern slope of the Western Caucasus) are presented. The maximum and minimum dZr age is 2973 ± 12 Ma and 318 ± 3 Ma, respectively; weighted average age of the four youngest dZr is ~322 ± 7 Ma. There are no signs of erosion products of the Jurassic magmatites involved in the structure of the Greater Caucasus and Crimean Mountains into the sedimentary basin, where the Novorossiisk–Anapa flysch was formed. The results have revealed a high degree of similarity between the provenance signals of the Danian sandstones from the Novorossiisk–Anapa flysch, some Paleogene–Neogene and Early Quaternary (Early Pleistocene) sandstones of the Western Caucasus and Western Cis-Caucasia, red-colored Upper Permian and Lower Triassic sandstones of the Moscow syneclise, as well as Late Quaternary alluvium at lower reaches of the Don and Volga rivers draining vast expanses of the Russian Plate. These facts suggest: (1) the absence of eroded mountain structures of the Greater Caucasus and Crimea in the middle Danian; (2) the main volume of detrital material composing the Novorossiisk–Anapa flysch was formed due to the recycling of Permian–Triassic and younger sequences of the Russian Plate. [ABSTRACT FROM AUTHOR]

We review the stellar magnetism studies published in 2022. We analyzed a total of 75 papers, which focus mostly on the study of magnetic fields in chemically peculiar and active cool stars. In the latter, migration of magnetic spots and change of their configuration is observed. Projects of spectrographs and spectropolarimeters for new big telescopes are also presented. [ABSTRACT FROM AUTHOR]

The paper presents magnetic field measurements and physical parameters for 96 stars. Observations were carried out in 2015 with the 6-m BTA telescope using the Main Stellar Spectrograph (MSS). By analyzing circularly polarized spectra, the magnetic fields of the stars HD 653, HD 8855, HD 94603, HD 188101 (KIC 6065699), HD 189160, HD 195464, and BD+44 4130 were discovered for the first time. No systematic measurement errors were detected. [ABSTRACT FROM AUTHOR]

This work reports on data on a moderate effusive-explosive eruption of a summit crater of Alaid volcano (Atlasova Island, Northern Kuril Islands) observed from September 10 to December 1, 2022. Based on satellite and visual data, it was determined that the strombolian-vulcanian activity resulted in two lava flows, 2.6- and 1-km long, that outflowed onto the southern slope of the volcano and at least 16 emissions occurred to heights of 2.5 to 6 km a.s.l. The ash plumes spread out mainly in the southeast and east-southeast directions with their maximum length reaching 300–530 km. The eruption posed a danger to local airlines. The lava outflow provoked the formation of lahars that descended along the southern slope of the volcano and reached the island coast. The alluvial fan formed from mudflow masses partially deposited beyond the coastline, causing accretion of the island land. [ABSTRACT FROM AUTHOR]

The influence of the addition of Bi to the dilute ferromagnetic semiconductor (Ga,Mn)As on its electronic structure as well as on its magnetic and structural properties has been studied. Epitaxial (Ga,Mn)(Bi,As) layers of high structural perfection have been grown using low-temperature molecular-beam epitaxy. Post-growth annealing of the samples improves their structural and magnetic properties and increases the hole concentration in the layers. Hard X-ray angle-resolved photoemission spectroscopy reveals a strongly dispersing band in the Mn-doped layers, which crosses the Fermi energy and is caused by the high concentration of Mn-induced itinerant holes located in the valence band. An increased density of states near the Fermi level is attributed to additional localized Mn states. In addition to a decrease in the chemical potential with increasing Mn doping, we find significant changes in the valence band caused by the incorporation of a small atomic fraction of Bi atoms. The spin–orbit split-off band is shifted to higher binding energies, which is inconsistent with the impurity band model of the band structure in (Ga,Mn)As. Spectroscopic ellipsometry and modulation photoreflectance spectroscopy results confirm the valence band modifications in the investigated layers. [ABSTRACT FROM AUTHOR]

The Puchezh–Katunki crater is located in the central part of the East European Platform in the area of the Gorky Reservoir, has a diameter of ~80 km, and is morphologically expressed by the central uplift of the basement (Vorotilov knoll) and the ring depression surrounding it, on the periphery of which there is a ring terrace. The crater is filled with various coptogenic (explosive (?)) formations: breccias of various types and bodies of suevites and tagamites. The results of studying the U‒Th‒Pb isotope system of detrital zircon grains from variegated explosive Puchezh breccias in the northwestern part of the ring terrace (three samples) are presented. The weighted average of the three youngest U‒Pb dates of detrital zircons from all studied samples is 258 ± 7 Ma, which corresponds to the Late Permian. We take this date as the lower age limit of the Puchezh breccias. The age sets of detrital zircon grains from the studied samples and from (1) crystalline rocks of the Vorotilov knoll and suevites of the ring depression and (2) Upper Permian–Lower Triassic sandstones of the Zhukov Ravine reference section (Moscow Syneclise) were compared. The absence of zircon grains, whose U‒Th‒Pb isotope system is similar to the parameters of those from the rocks of the Vorotilov knoll and suevites among the detrital zircons from the Puchezh breccia indicates the local nature of the Puchezh–Katunki explosion, the impact-thermal impact of which did not affect the detrital zircons in rocks of the marginal part of the ring terrace of the crater. A high degree of similarity of the age sets of detrital zircon grains from the lens of redeposited sandstones of the Puchezh breccias and Upper Permian rocks of the Zhukov Ravine section indicates that the Puchezh breccias were formed mainly due to the reworking of the Upper Permian–Lower Triassic sequences underlying the explosive formations. We consider the Uralian paleo-orogenic belt as the main provenance area for the deposits of the central regions of the East European Platform in the stratigraphic interval close to the Permian–Triassic boundary. The deposits were formed as a result of a high degree of mixing and averaging of clastic material of sedimentary flows containing the Uralian and Asha provenance signals. [ABSTRACT FROM AUTHOR]

A set of methods (seismoacoustic profiling, analysis of continuous borehole sections, stratigraphic studies on malacofauna, and radioisotope age dating) was used to identify the Novocaspian, Mangyshlakian, Khvalynian, Atelian, Hyrkanian, and Upper Khazarian horizons in the Upper Quaternary deposits of the Northern Caspian shelf. Based on AMS radiocarbon and uranium-thorium dating, the time of their accumulation is determined, respectively, in the intervals of 0 to 8.5, 8.5 to 13, 13 to 50/60, 50 to 70, >60 to 120 and more than 120 000 years ago. [ABSTRACT FROM AUTHOR]

Estimates that are accurate by order of magnitude have been obtained for some characteristics of the linear and nonlinear approximations of the isotropic classes of the Nikol'skii–Besov-type B p , θ ω of periodic functions of several variables in the spaces Bq,1, 1 ≤ q ≤ ∞. A specific feature of those spaces, as linear subspaces of Lq, is that the norm in them is "stronger" than the Lq-norm. [ABSTRACT FROM AUTHOR]

Two-phase gas-particle flow over a flat plate of finite thickness in a channel at a high subsonic velocity and supersonic transverse flow past a cylinder are considered. The leading edge of the plate is wedge-shaped or represents a smooth bluntness of constant radius. The wedge surface and the front bluntness are specified both smooth and rough. The roughness is modeled by a two-dimensional profile based on an experiment. Spherical particles and a mixture of particles in the form of ellipsoids of revolution, rectangular prisms, prisms with flat-cut vertices, and tetrahedrons are considered. The parameters of each of the forms vary. The impact interaction model proposed earlier and consistent with the experimental data on the coefficients of restitution of the center-of-mass velocity is used to determine the translational and rotational velocities of non-spherical particles after rebound. Along with monosized particles, a dispersed phase with a spread of particles in size is considered. The role of the studied factors of random nature which affect the flow pattern and the dispersed phase parameters is found. [ABSTRACT FROM AUTHOR]

This paper presents the results of magnetic field measurements for 19 chemically peculiar stars in three open star clusters IC 4756, Per, NGC 7092. More than 80 spectra of circularly polarized radiation were obtained with the Main Stellar Spectrograph (MSS) at the 6-m BTA telescope of SAO RAS. It was found that the magnetic field value in these clusters is more than three times less than in the young Orion OB1 association. Apparently, unique conditions developed in this association allowed the generation of super-strong magnetic field during the formation of stars. [ABSTRACT FROM AUTHOR]

The power capability of Li-ion batteries has become increasingly limiting for the electrification of transport on land and in the air. The specific power of Li-ion batteries is restricted to a few thousand W kg−1 due to the required cathode thickness of a few tens of micrometers. We present a design of monolithically-stacked thin-film cells that has the potential to increase the power ten-fold. We demonstrate an experimental proof-of-concept consisting of two monolithically stacked thin-film cells. Each cell consists of a silicon anode, a solid-oxide electrolyte, and a lithium cobalt oxide cathode. The battery can be cycled for more than 300 cycles between 6 and 8 V. Using a thermo-electric model, we predict that stacked thin-film batteries can achieve specific energies >250 Wh kg−1 at C-rates above 60, resulting in a specific power of tens of kW kg−1 needed for high-end applications such as drones, robots, and electric vertical take-off and landing aircrafts. Lithium-ion batteries require a minimum cathode thickness of a few tens of micrometers, which limits their specific power. Here, the authors predict that stacked thin-film batteries with 0.15-2 µm thin cathodes can achieve a tenfold increase in specific power to over 10 kW kg−1 and demonstrate the design concept in two monolithically stacked thin-film cells. [ABSTRACT FROM AUTHOR]

The paper presents the first results of the ongoing spectropolarimetric monitoring of magnetic fields of stars, whose chemically peculiar nature has been previously revealed with the 1-m SAO RAS telescope. We selected the sample candidates using the photometric data of the Kepler and TESS space missions. The efficiency of the method of searching for new CP stars based on photometric light curves has been confirmed. We present the magnetic field measurements and estimate the atmospheric parameters of the objects under study. [ABSTRACT FROM AUTHOR]

The choice of design and operational parameters of vortex dust collectors (VDC) influences energy costs for ensuring the required dust collection efficiency at a given volumetric cleaned gas productivity. Data on the most expedient VDC design parameters are presented. Based on analytical relationships and computer simulation data, a method for calculating hydraulic resistance of the newly designed VDC and its separating capacity has been developed. [ABSTRACT FROM AUTHOR]

Macroscopic fossils as composite molds and casts of Ediacara-type soft-bodied organisms were found in the Dzhezhim Formation of the Timan Range for the first time. Among them, representatives of palaeopascichnids, arboreomorphs, chuariomorphids, microbial colonies, and trace fossils were identified. This finding of such a large number of various Ediacaran fossils on the Timan Range not only develops our understanding of their paleogeographic range but also clarifies the age limits of the deposition of the Dzhezhim Formation, the stratigraphic position of which in the Upper Precambrian section was controversial. [ABSTRACT FROM AUTHOR]

We searched again for a radial (vertical) gradient of the longitudinal magnetic field of the chemically peculiar star CVn. We considered the history of magnetic studies of this object demonstrating large differences in the data obtained with different methods. Such differences can be explained by the fact that the magnetic field sharply drops (by 2 orders stronger than in the case of a dipole structure) with height in the atmosphere. The spectroscopic, spectropolarimetric, and photometric data indicate that the large- and small-scale structure of the atmosphere of CVn has not changed over more than 90 years of observations. [ABSTRACT FROM AUTHOR]

The paper presents the results of searching and studying magnetic fields of 4 chemically peculiar stars in the Pleiades open cluster and 21 CP stars in the kinematic group of the same name. Observations were carried out at the 6-m BTA SAO RAS telescope with a circular polarization analyzer. Four stars with anomalously strong silicon lines were previously specified in the Pleiades cluster. We did not find a magnetic field in any of them. The Pleiades group contains seven non-magnetic HgMn stars and 14 potentially magnetic Ap/Bp stars of various types. We detected or confirmed magnetic fields in eight objects. The fraction of magnetic CP stars is 57 relative to Ap/Bp. Not a single object was found in the group, in which the longitudinal magnetic field would exceed 2 kG. [ABSTRACT FROM AUTHOR]

We report eight new exoplanet candidates discovered at the Special Astrophysical Observatory of the Russian Academy of Sciences using the transit technique. Photometric observations were performed with a 50-cm robotic telescope during the second half of 2020. Transits with depths of and periods were detected in – stars. All the stars considered are dwarfs with radii (with an uncertainty of up to for a single star). We use simulations to estimate the candidate radii (all are greater than 1.4 times the Jovian radius), semi-major axes of their orbits (0.012–0.035 AU), and other orbital parameters. We report the transit light curves for two stars obtained in 2022 based on individual observations. [ABSTRACT FROM AUTHOR]

Abstract—We present a review of the papers written in the research field of stellar magnetism in 2021. The instruments, observation, and data analysis methods, photometry, spectroscopy, and spectropolarimetry results are considered. We present new data on magnetic fields of chemically peculiar stars and other objects of various types. [ABSTRACT FROM AUTHOR]

The transport of neutrons and γ quanta of various energies through a polymer composite based on tungsten-filled track membranes is studied. Expressions describing the attenuation coefficients of γ quanta and neutrons in the developed polymer composite are obtained. The change in the intensity of beams of γ quanta and neutrons when passing through a periodic layered structure consisting of polymer composite layers with tungsten and pure tungsten depending on the number of layers is investigated. [ABSTRACT FROM AUTHOR]

We studied the columns of boreholes and of sediment cores in the Taman shelf area and on the Caucasian continental slope, which reveal shallow and deep-water facies of the interglacial Karangat horizon. Shallow-water deposits include clayey and sandy-shell varieties, containing stenohaline marine mollusk fauna. Deep-water deposits are sapropel and coccolith layers with marine flora of diatom algae and coccolithophorids. [ABSTRACT FROM AUTHOR]

The paper presents data on granites and gneisses recovered by Kulindinskaya-1 hole drilled in the central part of the Siberian Craton. The biotite granites retain a porphyritic texture, correspond to I-type according to their compositional features, are enriched in LREE and moderately depleted in HREE, and have negative Eu, Sr, and Nb and positive Zr anomalies. The U−Pb zircon age of the granites is Neoarchean (2525 ± 10 Ma), with single cores of zircon grains dated at about 2.6 Ga, which likely suggests a crustal source of the granitic magmas. The model age TNd(DM) = 2.77 Ga of the granite shows that the crust from which the initial melts were derived had been formed shortly before the melting episode. In terms of age and all characteristics, the granites are close to those of the Yurubchen massif, which was drilled through in the western part of the Tunguska superterrane. The biotite gneiss was apparently derived from sedimentary rocks and was heavily reworked when the granites were emplaced. The enrichment of the gneiss in Cr and Ni is probably inherited from the sedimentary protolith, whereas the REE, HFSE, and LILE concentrations and distribution in the gneiss are similar to those of the granite. The concordant (D < 1%) U−Pb zircon ages (according to LA-ICP-MS data) broadly vary from 3284 to 2620 Ma, with two major peaks at 2717 and 2678 Ma. The model age of the gneiss TNd(DM) = 2.91 Ga confirms a contribution of the ancient crustal component to the sedimentary protolith of the rock. The minimum age of the detrital zircon, 2.62 Ga, determines the maximum age limit for sedimentation, and the minimum age limit is set by the age of the granite intrusions at 2.53 Ga. According to our data, the Archean gneisses and granites recovered by the Kulindinskaya-1 drillhole probably compose the eastern part of the Neoarchean Tunguska superterrane. Ereminskaya-101 drillhole, which was drilled 20 km northeast of Kulindinskaya-1, recovered gneisses with model ages TNd(DM) from 2.30 to 2.37 Ga, which belong to the adjacent Taimyr−Baikal suture zone with widespread Paleoproterozoic rocks. The contrasting crustal history of the adjacent complexes provides grounds to suggest that they were tectonically combined, which is an additional reason to consider the Taimyr−Baikal suture zone as a Paleoproterozoic collisional orogen. [ABSTRACT FROM AUTHOR]

We establish the exact-order estimates for the best orthogonal trigonometric approximations of the Nikol'skii–Besov classes B 1 , θ r (T d), 1 ≤ θ ≤ ∞, of periodic functions of one and many variables with predominant mixed derivative in the space Bθ, 1 (T d). In the multidimensional case, d ≥ 2, we establish the exact-order estimates for the approximations of the indicated classes of functions by their step-hyperbolic Fourier sums and determine the orders of orthoprojection widths in the same space. The behaviors of the corresponding approximation characteristics of the Sobolev classes W 1 , α r (T d) with d ∈ {1, 2} are also investigated. [ABSTRACT FROM AUTHOR]

The first results of the geochronological dating of the specific sill-like gabbrodiorite–granodiorite intrusive bodies within the areal extent of the Paleoproterozoic Ladoga complex, singled out at an early stage of the tectono–metamorphic evolution of the Svecofennides in the southeastern part of the Fennoscandian Shield are presented. Their affinity to the fold-and-thrust paragenetic assemblage of the Meyeri zone, which separates the northern and southern domains of the Ladoga region, in the shape of plated or tabular-like magmatic bodies that fill the feather joints of low-angle thrust faults, is shown. The results of zircon dating by two technologies of the U–Pb method, indicating the time span of the early kinematic stage of the Svecofennian tectogenesis and the according plutonic igneous and metamorphic events at ca. 1.87 Ga, as well as the time limit of the imprinted folding event of the second deformation stage at about 1.83 Ga, are compared. [ABSTRACT FROM AUTHOR]

Abstract—We present the magnetic field measurements results for 74 stars observed in 2014. The sample of objects consists of chemically peculiar and standard stars. Observations were carried out with the 6-m BTA telescope of SAO RAS using the Main Stellar Spectrograph (MSS). Magnetic field for HD 168481, HD 184961, HD 187128 and HD 214923 were discovered for the first time by analyzing the circularly polarized spectra. [ABSTRACT FROM AUTHOR]

The results of computer modeling of gas dynamics of a swirl dust collector with various designs of the axial-vane swirler of secondary flow are presented. It is shown that maximum dust collection efficiency with minimal energy consumption can be achieved by installing curved vanes with variable crosssectional area in the intervane space of the axial-vane swirler of secondary flow. [ABSTRACT FROM AUTHOR]

New results of U–Th–Pb isotopic dating of detrital zircon grains from the sandstones of the Upper Tauric Formation of the Crimean Mountains, belonging to the Lower Jurassic part of the Tauric Group, are presented. Comparison of the obtained age sets of detrital zircon grains with similar data for the clastic rocks of both lower and higher stratigraphic levels of the Cimmerides of the Crimean Mountains shows a significant difference between them. This reflects radical changes in the sources of sediment supply for the studied strata, which took place at the Triassic–Jurassic boundary and at the beginning of the Middle Jurassic. During the Late Triassic–Jurassic time, the sedimentary basins of the Crimean Mountains were formed directly on the southern (in present-day coordinates) continental margin of the East European segment of Eurasia. During the Late Triassic, the vast Scythian–Tauric megabasin was located here. Mostly shallow-water sediments accumulated in its northern part, in the Scythian sedimentary basin, and flysch deposition took place in its southern part, in the Tauric deep-water sedimentary basin. The clastic components of the flysch are dominated by the products of destruction of the crystalline basement complexes of the Sarmatian segment of the East European craton (EEC), the equivalents of the crystalline complexes exposed at present within the Ukrainian Shield and the Voronezh crystalline massif. The clastic material was supplied to the Tauric basin in transit via the Scythian basin. At the Late Triassic and Early Jurassic boundary, detrital material from the EEC ceased flowing into the Tauric sedimentary basin. But detrital material, the primary sources of which were the crystalline complexes of Gondwana and the peri-oceanic complexes of the Rheic and Paleo-Tethys oceans, started to flow into it. This means that the paleogeographic situation on the southern margin of the East European segment of Eurasia changed dramatically during the Early Jurassic. The Scythian–Tauric megabasin as it existed during the Late Triassic disappeared. The Dobrogea–Crimea Uplift emerged in its northern part (Scythian sedimentary basin). However, no significant changes in the depositional environment took place in its southern part (Tauric sedimentary basin). Deep-water flysch accumulation continued there during the Early Jurassic. This inherited sedimentary basin is hereinafter referred to as Late Tauric to emphasize the difference of its sedimentary fill from the fill of the Tauric basin. At the boundary of the Early and Middle Jurassic or at the very beginning of the Middle Jurassic, sediment accumulation ceased in the Late Tauric sedimentary basin, and the Upper Triassic and Lower Jurassic strata, successively accumulated in the Tauric and Late Tauric basins, underwent deformations. Later, the system of subbasins of the Crimean Mountains formed on the basement composed of these deformed complexes during the Middle and Late Jurassic. The clastic material that accumulated in the system of subbasins of the Crimean Mountains during the Middle and Late Jurassic was mostly of local (regional) origin, but a new source of detrital material, which supplied Permian–Triassic detrital zircon grains to these subbasins, appeared in addition. [ABSTRACT FROM AUTHOR]

We obtain order estimates for the M-dimensional Kolmogorov widths of the Nikol'skii–Besov classes of periodic functions of many variables with predominant mixed derivative in the metric of the space of quasicontinuous functions (QC-space). [ABSTRACT FROM AUTHOR]

Abstract—Based on our previous and recent magnetic field observations of a chemically peculiar star 53 Cam with the 6-m telescope and literary sources, we can make a conclusion that its magnetic field structure differs from a simple dipole. At the same time the results of measurements from hydrogen lines are described by a simple dipole model. However, data obtained from metallic lines (including magnetic mapping methods) point to a more complex field structure. We performed new observations of the magnetic field in the Balmer series hydrogen lines in the near UV-range. These peculiarities may show that the field strength increases with depth in the atmosphere of 53 Cam. [ABSTRACT FROM AUTHOR]

We have obtained the exact-order estimates for some approximative characteristics of the Sobolev classes W p , α r and Nikоl'skii–Besov classes B p , θ r of periodic functions of one and several variables in the norm of the space B∞,1. Properties of the linear operators realizing the orders of the best approximation for the classes B ∞ , θ r in this space by trigonometric polynomials generated by a set of harmonics with "numbers" from step hyperbolic crosses are investigated. [ABSTRACT FROM AUTHOR]

The article describes the operating modes of a dust-collecting filter of an industrial aspiration system. The kinetics of the total pressure drop across the filter during its emergency operation (clogging of the structure with dust) is analyzed. A mathematical model for determining the duration of the filter operation before the onset of intensive dust slip through the filter in the absence of filter regeneration for a low-dispersed highly concentrated dust and gas flow has been developed. [ABSTRACT FROM AUTHOR]

We obtain the exact-order estimates for the orthoprojection widths and similar approximating characteristics of the Sobolev classes W p , α r and Nikol'skii–Besov classes B p , θ r of periodic functions of one and several variables in the norm of the space B1,1. In addition, it is established that the sequence of norms of linear operators realizing the orders of the best approximations for the classes B 1 , θ r in the space B1,1 with the help of trigonometric polynomials with "numbers" of harmonics from step hyperbolic crosses is unbounded in the many-dimensional case. [ABSTRACT FROM AUTHOR]

We obtain the exact-order estimates for the orthoprojection widths and similar approximating characteristics of the Sobolev classes W p , α r and Nikol'skii–Besov classes B p , θ r of periodic functions of one and several variables in the norm of the space B1,1. In addition, it is established that the sequence of norms of linear operators realizing the orders of the best approximations for the classes B 1 , θ r in the space B1,1 with the help of trigonometric polynomials with "numbers" of harmonics from step hyperbolic crosses is unbounded in the many-dimensional case. [ABSTRACT FROM AUTHOR]

This paper is devoted to the study of gas-and-dust disks around young AB stars in the association Orion OB1. The observed spectral flux values of these stars in the wavelength range of 0.36–100 μm are determined. We used the results of multicolor photometric observations in the -bands, as well as data from the WISE and IRAS catalogs. It is shown that many program stars have radiation excesses in the far IR range. It is assumed that such an excess may be the result of the formation of a gas-dust disk around the program stars similar to those for Vega-type stars. [ABSTRACT FROM AUTHOR]

Chlamydomonas and other microalgae are capable of assimilating exogenous organic compounds. Additional carbon and energy sources affect different aspects of cell physiology. Simultaneous comparison of an auto- and mixotrophic batch of Chlamydomonas cultures indicates that acetate strongly stimulates the growth rate as well as the activity of respiration and photosynthesis in the exponential growth phase. In the middle of exponential growth, mixotrophy was characterized by a decrease in chlorophyll content that was followed by its elevation in the stationary phase. Chlamydomonas metabolomic profiles detected with GS-MS differed significantly as a result of trophic conditions. The maximum distinction was also observed in the middle of the exponential phase. The main feature of autotrophic cells is a higher carbohydrate content. Under the presence of acetate, cells demonstrated an intensive accumulation of fatty acids. This phenomenon is possibly related to the stimulation of lipid synthesis in the presence of additional sources of acetyl groups and by a higher content of carboxylates that were the result of elevated respiration. In the late stationary phase, mixotrophic cells exhibited a metabolomic shift towards autotrophy, probably due to acetate exhaustion. The importance of autotrophy at later stages of batch culture development correlated with chlorophyll accumulation in the early stationary phase. Thus, complicated trophic-induced metabolic and physiological alterations were revealed in Chlamydomonas cells during growth. [ABSTRACT FROM AUTHOR]

We establish the exact-order estimates for some approximating characteristics of the classes W p , α r and B p , θ r of periodic functions of one and many variables in the norm of the space B∞,1. [ABSTRACT FROM AUTHOR]

In 2020–2021 the palaeopascichnid fossils were found in the Krasnaya Gorka Site (Shirokovsky Reservoir, Kosva River area, Perm Region), a type Vendian fossil locality (problematic discoidal casts and arumberiamorph structures) for the Central Urals discovered by Yu.R. Bekker in 1972. In the stratigraphical context, the fossil locality is associated with Chernyi Kamen Formation of the Upper Vendian Sylvitsa Group. The results of morphometric analysis of palaeopascichnid fossils made possible to distinguish three morphological types: Palaeopascichnus delicatus, Yelovichnus gracilis, and Palaeopascichnus linearis. Finding of a large number of palaeopascichnid fossils both develops the understanding of their palaeobiology and taphonomy, and also demonstrates that palaeontological potential of the type fossil locality and one of the most representative section of the Chernyi Kamen Formation has not entirely been realized. [ABSTRACT FROM AUTHOR]