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Long-term trends and dependences on solar activity were derived for wave disturbances at mesopause altitudes (80−100 km) based on temperature variations obtained by spectral observations of the hydroxyl airglow at the Zvenigorod Science Station, Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, in 2000−2024, as well as by methods of statistical analysis. Their activities were determined by digital frequency filtering in three regions of wave periods, such as 0.7−2.0, 1.4−4.1, and 2.7−8.2 h with maxima at 1, 2, and 4 h. The root-mean-square values of temperature half-differences served as an indicator of wave activity. Both year-round and average seasonal (winter and summer) values were analyzed. According to the study results, the wave activity is characterized by positive trends with their dependence on the frequency band of disturbances (in winter, the trend is greater in the high-frequency band, and in summer, the trend is greater in the low-frequency band). The dependence on solar activity is positive. Its values are greater for the high-frequency band of disturbances, as well as in winter. [ABSTRACT FROM AUTHOR]

Using the statistical properties of the solution of the Fokker–Planck–Kolmogorov equation (FPK) for velocities and coordinates and using the vortex identification method, quantitative estimates of the distributions of various characteristics of cyclones and anticyclones (including lifetime, wind speed, size, characteristic forcing, and kinetic energy) depending on their intensity have been obtained. The calculations are based on ERA5 reanalysis data for the period 2010–2021. The vortex lifetimes estimated using the FPK correspond to the lifetimes obtained using the vortex identification method, and the theoretical distribution of cyclones by intensity practically coincides with those observed. The characteristics of vortices during their life cycle are also investigated. In general, all the characteristics of cyclones analyzed increase with their intensification. However, for intense anticyclones, the increase is not as pronounced as for cyclones. [ABSTRACT FROM AUTHOR]

Currently, digital technologies for modeling buildings and infrastructure are successfully used in international and national practice for the implementation of complex construction projects and large-scale programmes. At the same time, the transition to machine-readable standards, implemented in many countries to improve the quality of design documentation and automate its verification, faces serious methodological and technical challenges. First of all, these challenges are due to the complexity of digital models, as well as the variety of requirements formulated in natural languages and imposed on these models at the state, regional, departmental, and corporate levels. Attempts to create catalogs of requirements and software tools for their management and use generally have specific purposes and do not provide necessary completeness, normalization, consistency, interconnectedness, unambiguity, traceability, and validability of requirements description. In this regard, it seems reasonable to use formal methods for specification and verification of requirements that have proven themselves in system and software engineering. This paper provides a comparative analysis of software tools for automated verification of regulatory requirements in the construction domain. There is a growing interest in tools focused on international standards, such as Industry Foundation Classes (IFC) and Information Delivery Specification (IDS), that allow one to control the completeness of the object and attribute composition of models, as well as the clarification of acceptable domains of values values. However, the IDS standard is not formalized and does not enable the specification of requirements expressed in terms of arbitrary algebraic conditions. The EXPRESS object-oriented data modeling language, in which the IFC data schema is specified, seems promising for the formal specification and verification of requirements for digital models used in the construction industry. As a substantiation, it is shown that IDS specifications can be represented by logical expressions and EXPRESS functions, as well as that arbitrary algebraic conditions can be specified as EXPRESS declarative rules. To illustrate the proposed approach, we consider some examples of the formalization of requirements from national construction standards and sets of rules concerning the safety of buildings, structures, and processes. The possibility of harmonizing the proposed formal approach with the IDS standard by defining new facets for the representation of local, uniqueness, and global EXPRESS rules is also discussed. [ABSTRACT FROM AUTHOR]

The authors consider variational inequalities in the Hilbert space and two algorithms for their approximate solution: extrapolation from the past and operator extrapolation. Both algorithms have less computationally expensive iterations than the the classical extragradient algorithm: only one operator computation rather than two is needed. Non-asymptotic linear convergence rate estimates are proved for the variational inequalities with the Lipschitz continuous operators satisfying the generalized strict monotonicity condition. The results are new and improve the available estimates. [ABSTRACT FROM AUTHOR]

This work discusses the synthesis of magnetite nanoparticles using microfluidic method. The main characteristics of the resulting nanoparticles were investigated, including chemical composition, size distribution, saturation mass magnetization, and coercive force. To assess the possibility of using nanoparticles for medical and biological purposes, the hemolytic activity of a suspension of magnetite nanoparticles was studied. [ABSTRACT FROM AUTHOR]

A proton beam scanning system for silicon sample irradiation has been developed in the frame of the EG-5 accelerator upgrade project and joint work with Micron JSC and Angstrom JSC located in Zelenograd. Together with employees of SPE ESTO JSC (Zelenograd), an automated system has been developed, produced, and tested on the basis of the EG-5 electrostatic accelerator to carry out the technological operation of ion implantation of silicon wafers for the production of power electronics. The developed system is an experimental platform that allows varying the distribution of the sample surface coating during scanning with accelerated particles. [ABSTRACT FROM AUTHOR]

Based on a new mathematical framework and large multi-year multi-mission data sets, we reconstruct electric currents and magnetic fields around the dayside magnetopause and their dependence on the incoming solar wind, IMF, and geodipole tilt. The model architecture builds on previously developed mathematical frameworks and includes two separate blocks: for the magnetosheath and for the adjacent outer magnetosphere. Accordingly, the model is developed in two stages: 1) reconstruction of a best-fit magnetopause and underlying dayside magnetosphere, based on a simple shielded configuration, and 2) derivation of the magnetosheath magnetic field, represented by a sum of toroidal and poloidal terms, each expanded into spherical harmonic series of angular coordinates and powers of normal distance from the boundary. The spacecraft database covers the period from 1995 through 2022 and is composed of data from Geotail, Cluster, Themis, and MMS, with the total number of 1-min averages about 3 M. The modeling reveals orderly patterns of the IMF draping around the magnetosphere and of the magnetopause currents, controlled by the IMF orientation, solar wind pressure, and the Earth's dipole tilt. The obtained results are discussed in terms of the magnetosheath flux pile-up and the dayside magnetosphere erosion during periods of northward or southward IMF, respectively. [ABSTRACT FROM AUTHOR]

In the experiments of Mössbauer spectroscopy, transmission electron microscopy (TEM) and atomic force microscopy (AFM) the morphology and structurization of the carbon phase, the charge state of europium and the dynamic properties of europium bis-phthalocyanine pyrolysed derivatives, including the Debye temperature, were revealed. It was found that the pyrolysis of europium bis-pthalocyanine resulted in the amorphous carbon matrix and nanoscaled graphene clusters both forming turbostratic carbon phase. The europium ions in the charge state Eu3+/Eu2+ were detected. The data indicated that localization of Eu ions took place between layers of graphenes similar to graphite intercalation compounds. It was shown that an isomeric shift, linewidths and the magnitude of the resonant absorption are essential characteristics of structural transformations at the pyrolysis of rare earth bis-phthalocyanines. [ABSTRACT FROM AUTHOR]

The greater transparency of the polymer obtained by adding a small amount of molecular iodine to the liquid photopolymerizing composition is satisfactorily explained by the formation of a π,σ-type charge transfer (CT) complex of oligocarbonate dimethacrylate with molecular iodine. The CT band at 360 nm absorbs a significant part of the actinic radiation such that the rate of the photolytic decomposition of the photoinitiator in the initial polymerization stage permits release of free volume from the polymer into the liquid part of the photopolymerizing composite. Layer-by-layer photopolymerization occurs at advanced stages due to the thin upper layers exposed to UV irradiation becoming steadily more transparent. [ABSTRACT FROM AUTHOR]

Predictive estimates of changes in the climatological boundary of the permafrost zone as a function of the average annual air temperature in the Bolshezemelskaya tundra under various global economy scenarios until the middle of the XXI century have been obtained. The permafrost climatological boundary shift in the northeasterly direction observed in the period from 1950 to 2010 was determined from the threshold average annual air temperature. According to the adjusted scenario forecasts obtained using the climate model, it will continue in the coming decades under any global economy scenario and is an inevitable consequence of the anthropogenic influence on the climate. The study results are important for assessing the prospects and development of a long-term observation network created to monitor the permafrost state and greenhouse gas fluxes in the Russian Federation. [ABSTRACT FROM AUTHOR]

Terbium orthoferrite (TbFeO3) perovskite demonstrates specific magnetic properties which are object of interest. Aggregated granular nanopowder of TbFeO3 particles of 85.6 nm were obtained by direct solution combustion method. The orthorhombic perovskite structure (space group Pbnm) of the terbium orthoferrite was confirmed by powder X-ray diffraction, Raman spectroscopy and 57Fe Mössbauer spectroscopy. The unusual granular morphology and mesoporous structure of the nanopowder were investigated by scanning electron microscopy and adsorption-structural analysis via low-temperature (77 K) adsorption-desorption of nitrogen with a total porosity of 0.0145 cm³/g and average pore width of 12 nm. The magnetic properties of TbFeO3 nanoparticles were thoughtfully studied, M = 34.2 emu/g at T = 10 K, Hc = 300 Oe. The onset of reorientation of the Fe3+ spin system at T ~ 18 K and the antiferromagnetic ordering of Tb3+ ions at T ~ 4 K were observed by vibrational magnetometry. Obtained results confirm the flexible paramagnetic to antiferromagnetic behavior of granular TbFeO3 nanopowder. Highlight: Granular nanopowder of TbFeO3 was obtain by direct solution combustion method. Aggregated granular morphology of perovskite TbFeO3 was confirmed. Magnetization of TbFeO3 granules is in pronounced dependence of temperature. [ABSTRACT FROM AUTHOR]

New homodimers of 1,2,3-triazolyl nucleoside analogs based on 6-methyluracil, which are linked by the polymethylene linker at the N(1) or N(3) atoms, were synthesized. Screening of in vitro antiviral activity against influenza A virus (H1N1) and Coxsackievirus B3 revealed the lead compound that in vitro inhibited the replication of Coxsackievirus B3 with a half-maximal inhibitory concentration (IC50) and a half-maximal cytotoxic concentration (CC50) of 30.1 and >374 µmol L−1, respectively. A dependence of the antiviral activity on the length of the polymethylene linker connecting the 6-methyluracil and 1,2,3-triazolyl-β-d-ribofuranosyl fragments was found. [ABSTRACT FROM AUTHOR]

The authors propose and investigate a new algorithm for solving variational inequalities in Hilbert spaces. The proposed iterative algorithm is regularized by the operator extrapolation method using the Halpern scheme. In terms of the amount of computation required for the iterative step, the algorithm has an advantage over the Korpelevich extragradient method and the method of extrapolation from the past. For variational inequalities with monotone, Lipschitz continuous operators acting in Hilbert space, a theorem on the strong convergence of the method is proved. [ABSTRACT FROM AUTHOR]

By covalent binding of 1,2,3-triazolyl nucleoside analogues by a polymethylene chain at the N3 atoms, a series of homodimers was synthesized, in which nucleic bases are replaced by quinazoline-2,4-dione moieties connected to the β-D-ribofuranose residues by 1,2,3-triazolylbutyl linkers. Screening of in vitro antiviral activity against influenza A (H1N1) and Coxsackie B3 viruses revealed a lead compound that showed high antiviral activity (IC50 = 11.6 μM) against influenza A/Puerto Rico/8/34 (H1N1) virus and a lead compound that exhibited high antiviral activity (IC50 = 12.2 μM) against enterovirus Coxsackie B3. [ABSTRACT FROM AUTHOR]

A series of new dimers of pyrimidine nucleoside analogues have been synthesized. The dimers are composed of two uracil or thymine fragments linked at N3 through a polymethylene bridge and bearing a β-D-ribofuranose residue linked to N1 of the nucleobase through a 1,2,3-triazolylalkyl spacer. Biological screening revealed that some of the synthesized dimers are active against influenza A (H1N1) virus and coxsackievirus B3 with IC50 values of 13 and 4.5 μM, respectively. [ABSTRACT FROM AUTHOR]

The INMIO-CICE hydrodynamic model of the Caspian Sea was used to calculate equilibrium river runoff and evaporation from the sea surface over a wide range of sea levels (from –85 to +50 m a.s.l.) for different climatic conditions: the Last Glacial Maximum (about 21 ka BP) and the pre-industrial climate (~1850). Data from the INMCM4.8 climate model were used as boundary conditions. It was found out that a river runoff of about 400 km3/yr was required in the Last Glacial Maximum to maintain the sea level at 35–50 m a.s.l. corresponding to the maximum values of the Khvalynian transgression. In the Last Glacial Maximum, evaporation from the sea surface decreased by 105–175 mm (12–22%), and a precipitation layer, according to the INMCM4.8 model, decreased by 50–70 mm (15–30%). These conditions caused the equilibrium runoff to decrease by about 10–20% compared to the pre-industrial conditions. Smaller absolute and relative changes corresponded to lower sea levels. The maximum evaporation decrease occurred at 5 m a.s.l. [ABSTRACT FROM AUTHOR]

The study analyzes the long-term average annual OH* temperature trend, the values of which were obtained from nighttime spectral measurements of hydroxyl airglow bands at Zvenigorod research station (56° N, 37° E) from 1957 to 2022. At present, this OH* temperature series, which reflects the thermal state of the mesopause region, is the longest in the world. On its basis, the linear trend and response of temperature to changes in solar activity are estimated both in general for the entire data set and for individual time intervals. In the first case, the trend was –0.23 ± 0.04 K/year. In the second case, the analysis showed a strong cooling in the mesopause region (–0.53 ± 0.34 K/yr) until the 1970s, which subsequently slowed to –0.14 ± 0.03 K/yr. Comparison of the results with other measurements and model calculations shows that the latter have lower trend values. It is suggested that the causes of the temperature trend, in addition to the increase in greenhouse gases, the main one being CO2, can be due to long-term changes in the dynamics of the upper atmosphere. [ABSTRACT FROM AUTHOR]

The kinetics of austenite decay and the modeling of thermal welding cycles on the installation of high-frequency currents of various sections of the thermal influence zone of medium-carbon medium-alloy steels were studied. The change in hardness and toughness at metal heating temperatures of 170°C to 1300°C is presented. The mechanical properties of the simulated thermal influence zone and the real welded joint are compared. [ABSTRACT FROM AUTHOR]

Technological aspects of creating a new brand of high-strength steel in the modern industrial conditions of the Magnitogorsk Iron and Steel Works are considered. [ABSTRACT FROM AUTHOR]

High power impulse magnetron sputtering (HiPIMS) parameters such as the frequency, duration and amplitude of the discharge current pulses can be adjusted over a wide range to change the energy conditions for coating formation. This in turn leads to changes in the structure and properties of the deposited coatings. Measurement of the energy flux onto the substrate during high power pulse magnetron sputtering of copper is the subject of this paper. It is shown that for a fixed peak discharge current and average discharge power, a significant increase in the energy transferred to the coating can be achieved by reducing the duration of the current pulses. In this case, both the total energy flux onto the substrate and the normalized energy transferred per unit volume of the coating will be increased. The reasons for the increase in energy are examined in the paper. The ability to control the energy transferred to the coating by adjusting the HiPIMS pulse parameters is demonstrated. [ABSTRACT FROM AUTHOR]

In the case of loss-of-coolant accidents (LOCAs) at a tokamak fusion reactor (TFR) due to the outflow of water from the cooling system of the first wall/blanket or the divertor into the vacuum vessel, free hydrogen can be released as a result of high-temperature oxidation of beryllium and, to a lesser extent, tungsten and carbon that make up the surface of the vacuum vessel walls and divertor. In a number of accident scenarios, air from the containment rooms can also enter the vacuum vessel. At sufficiently high concentrations of hydrogen in the resulting steam–gas mixture in the vacuum vessel, a fire or explosion can occur, which threatens the structural integrity of the reactor. The most important phenomenon affecting the formation of the region with an increased hydrogen concentration is hydrogen stratification. Therefore, the safety analysis of a TFR, including the promising Russian TFR, should include numerical estimates of the possibility of stratification of hydrogen released during an accident. The article presents a physical model that makes it possible to estimate the characteristic parameters and location of the region with an increased hydrogen content in the LOCA accompanied by the entry of air into the vacuum vessel. [ABSTRACT FROM AUTHOR]

Water insoluble calcium hydroxide Ca(OH)2 or calcium carbonate CaCO3 react with aqueous solution of (1-hydroxyethylidene)diphosphonic acid and nitrilotrimethylenephosphonic acid to form poorly soluble calcium (1-hydroxyethylidene)diphosphonate trihydrate and calcium nitrilotrimethylenephosphonate trihydrate, respectively. The reaction of calcium chloride CaCl2 with the disodium salt of ethylenediaminetetraacetic acid afforded poorly soluble calcium ethylenediaminetetraacetate hexahydrate. The reaction of suspensions of complexes of (1-hydroxyethylidene)calcium diphosphonate trihydrate, calcium ethylenediaminetetetraacetate hexahydrate and calcium nitrilotrimethylenephosphonate trihydrate with 2-aminoethanol led to the formation of water-soluble (1-hydroxyethylidene)bis(2-aminoethanol)calcium diphosphonate, tris(2-aminoethanol)calcium nitrilotrimethylenephosphonate, and bis(2-aminoethanol)calcium ethylenediaminetetraacetate, respectively. The molecular structure of calcium ethylenediaminetetraacetate hexahydrate was characterized by single-crystal X-ray diffraction method. [ABSTRACT FROM AUTHOR]

5-Alkyl-substituted derivatives of 1-(2-hydroxyethyl)-4,6-dimethyl-1H-pyrimidin-2-one (1) are synthesized for the first time. Pyrimidine 1 is an active pharmaceutical ingredient of the burn drug Xymedon, which has pronounced hepatoprotective properties. The cytotoxicity and cytoprotective properties of the synthesized pyrimidines against the Chang Liver cell line of hepatocytes are evaluated. It is shown that the introduction of an alkyl substituent into the pyrimidine ring of Xymedon have a significant negative impact on the hepatoprotective properties. [ABSTRACT FROM AUTHOR]

Ti1 – xAlxN coatings with different Al content (x = 0.1–0.43) are grown on WC–Co substrates by dual high-power impulse magnetron sputtering in the Ar/N2 atmosphere. The coating resistance to high-temperature oxidation is determined. For this, the phase composition change is investigated by synchrotron radiation during heating in the air from room temperature to 1100°С. Mechanical properties (hardness, elastic modulus, plasticity index, and plastic deformation resistance) are determined by nanoindentation of coatings before and after heating to 1100°С. X-ray diffraction patterns demonstrate the formation of the TiO2 phase on the surface of all coatings, while the formation temperature and the phase type (brookite or rutile) depend on the Al content in the coating. All coatings are not subject to spinodal decomposition into the TiN and AlN phases after heating to 1100°С. The Ti0.57Al0.43N coating possesses the highest heat resistance; it undergoes the smallest change in the phase composition and mechanical properties after the high-temperature treatment. [ABSTRACT FROM AUTHOR]

Studies of the properties of ZnxFe3 –xO4 (x = 0, 0.25, 0.5, 0.75, 1.0) magnetic nanoparticles synthesized by a modified hydrothermal method are presented in comparison with the properties of the same nanoparticles stabilized with polyacrylic acid ZnxFe3 –xO4@PAA. The structure, size, morphology, and magnetic properties of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT IR), physical properties measurements (PPMS), and Mössbauer spectroscopy. The synthesized nanoparticles are single-phase, without additional impurities, have a narrow size distribution and are in the superparamagnetic phase. From the (XRD) measurements, it was found that with an increase in the Zn content from x = 0 to x = 1.0, the sizes of the nanoparticles were increasing from 17 to 33 nm. Analysis of the Mössbauer spectroscopy data showed that when doped with Zn ions from x = 0 to x =1.0, the sizes of the nanoparticles were decreasing from 15 to 5 nm. The results of the Mössbauer studies showed that both ZnxFe3 –xO4 and ZnxFe3 –xO4@PAA has a core/shell type structure in which the core is magnetically ordered, whereas the shell does not have magnetic ordering. Mössbauer studies indicate that the coating of citric acid particles leads to their isolation from each other, reducing or eliminating interactions between particles, reducing the thickness of the paramagnetic shell, and thereby increasing the diameter of the core, which is in a magnetically ordered state. [ABSTRACT FROM AUTHOR]

Steam oxidation of beryllium dust, which will inevitably be formed and accumulated in the vacuum chamber of the ITER thermonuclear reactor, can occur in emergency situations associated with the water flow from the cooling system of the first wall or divertor into the vacuum chamber (LOCA-type accident). This process is accompanied by the release of free hydrogen, which creates a risk of fire or explosion when mixing with air. The safety analysis of a thermonuclear reactor should include numerical estimates of the degree of oxidation and the amount of hydrogen released. The paper presents an engineering model that allows, with a given steam content in the volume of the chamber, to determine the rate of hydrogen production during the oxidation of beryllium dust layers and the total amount of hydrogen formed during an accident. An analytical assessment of the oxidation rate of the dust layer is carried out. [ABSTRACT FROM AUTHOR]

Various methods of cluster analysis are used for identifying large-scale atmospheric circulation regimes (weather regimes (WRs)). In this paper we compare the four most commonly used clustering methods: k-means (KM), Ward's hierarchical clustering (HW), Gaussian mixture model (GM), and self-organizing maps (SOMs) to analyze WRs in the Euro-Atlantic (EAT) region. The data used for identifying WRs are 500 hPa geopotential height fields (z500) from the ERA5 reanalysis for 1940–2022. Four classical wintertime WRs are identified by the KM method—two regimes associated with positive and negative phases of the North Atlantic Oscillation (NAO+ and NAO–), a regime associated with the Scandinavian blocking (SB), and a regime characterized by elevated pressure over the Northern Atlantic. For summer months, the KM method gets WRs that are similar in spatial structure to the classical winter ones. The SOM method yields results that are almost identical to the results of the KM method. Unlike KM and SOM methods, HW and GM do not fully catch the spatial structure of all of the four classical winter EAT WRs and their summer analogues. Compared to WRs of the KM and SOM methods, WRs obtained by HW and GM methods explain less z500 variance; they have different occurrences, persistence, and transition features. Summer and winter WRs obtained by HW and GM methods are less similar to each other compared to WRs provided by the KM method. Average spatial correlation coefficients between mean z500 fields of WRs obtained by KM and HW methods are 0.76 in winter and 0.83 in summer; 0.70 in winter and 0.72 in summer for KM and GM methods; and 0.41 in winter and 0.44 in summer for the regimes compared between HW and GM methods, respectively. There are statistically significant trends of the seasonal occurrence of WRs found by some of the studied clustering methods—a positive trend for the occurrence of the NAO+ regime and a negative trend for the occurrence of the NAO-regime. [ABSTRACT FROM AUTHOR]

A study has been made of changes in some characteristics of daily precipitation in Russia for the winter and summer seasons in the 20th and 21st centuries using Coupled Model Intercomparison Project Phase 6 (CMIP6) climate models. In the modern period, model data are compared with data from meteorological stations and ERA5 reanalysis. For winter and summer, changes in mean seasonal precipitation, the number of days with precipitation, and the frequency of extreme precipitation are analyzed. For the modern period 1991–2020, according to empirical data, in winter on the territory of Russia, a significant increase in seasonal precipitation amounts and the frequency of days with extreme precipitation on the Far East coast and in the central part of European Russia (ER) are detected. A decrease in the frequency of days with precipitation at most meteorological stations in Russia by 4–6 days/10 years is also noted. In summer, an increase in precipitation amounts and the frequency of days with precipitation is found in Western Siberia and on the coasts of the Sea of Okhotsk and the Pacific Ocean. A decrease in the amount and frequency of precipitation is obtained for southern ER and the south of Eastern Siberia. Climate models, on average for the ensemble, show an increase in the relative amounts of precipitation and the extreme precipitation frequency over most of the Russia territory in winter, and these trends may intensify in the coming decades. In summer, on the contrary, for southern ER, as a whole, there is a slight decrease in the seasonal precipitation totals and the number of days with precipitation. However, strong intermodel differences, especially in the summer season, do not allow us to draw unambiguous conclusions about changes in precipitation characteristics in Russia in the next 30 years. By the end of the 21st century, changes will become more pronounced. For example, in ER and northern Siberia, a noticeable increase in winter precipitation amounts and the frequency of extreme precipitation may occur. By the end of the 21st century, a slight decrease in the precipitation totals and the number of days with precipitation is possible in summer in ER. [ABSTRACT FROM AUTHOR]

We investigate an unusual sequence and peculiar features of magnetotail changes during a storm‐range substorm initiated by the interplanetary shock. Auroral observations and measurements at several favorably distributed magnetospheric spacecraft allowed the construction of an adaptive time‐dependent magnetospheric model to quantitatively characterize the configurational changes and mapping variations. Several passages of low‐altitude spacecraft in polar orbits near midnight help reveal the magnetic configuration of the nightside tail‐dipole transition region. In this event, an intense auroral and convection activity (accompanied by an up to 1,500 nT increase in the SuperMag AL‐index index) emerged in the highly compressed magnetosphere after the passage of interplanetary shock followed by strongly southward interplanetary magnetic field (IMF). This directly driven phase of the activity continued for an hour and resulted in the formation of a hybrid magnetic configuration with dipolarized midtail and stretched field lines in the transition region. Observations of energetic particle isotropy boundary latitudes near midnight are consistent with the modeled magnetic configuration. In concert with a downward turn of the solar wind (SW) flow, and weakening of the IMF driver and convection, an unusual stretching signature of the inner magnetosphere magnetic field was observed as close as at r ∼ 5 to 7 Re; which resulted mostly from an increasing downward tilt of the thin azimuthal current. Classic substorm breakup signatures commenced at fairly low, ∼60° magnetic latitude, deep in the closed field line region, in association with the current sheet upward motion. It was followed by strong stepwise poleward auroral expansion. We discuss how these signatures deviate from standard substorm scenarios and may be potentially imparted by the aforementioned changes in SW flow direction and pressure. Key Points: Strong substorm with −50 nT storm‐like SymH variation and anomalies in the sequence of dynamical configurational changes of magnetotailThe magnetotail attained a highly stretched configuration, consistent with observed isotropy boundary locations near midnightChanges of solar wind flow orientation could potentially affect the dynamics of the magnetotail by modifying the instability threshold [ABSTRACT FROM AUTHOR]

A quantitative model of the magnetosheath (MS) magnetic structure is developed, using a multi‐year set of Geotail, Themis, Cluster, and MMS magnetometer and plasma instrument data. The MS database is created using an identification algorithm, based on observed magnetic field magnitudes and proton densities, normalized by their concurrent interplanetary values, followed by additional filtering with the help of standard bow shock (BS) and magnetopause (MP) models. The model architecture is based on the toroidal/poloidal formalism and a coordinate system that naturally accounts for the tailward flaring of both boundaries. The magnetic field expansions include 960 free coefficients, derived by fitting the model to a grand data set, split into independent training and validation subsets with 1,291,380 and 411,933 1‐min records, respectively. The model faithfully reproduces basic types of the interplanetary magnetic field (IMF) wrapping around the MP. Regular IMF sectors result in strongly dawn‐dusk asymmetric draping, with much larger magnitudes at the quasi‐perpendicular dusk side of BS, and weaker at the quasi‐parallel dawn side, where the MS field lines are bent and dragged tailward. Except in the case of the flow‐aligned IMF orientation, the subsolar field steadily grows toward the MP, and the effect is clearly IMF Bz‐dependent: the field and its gradient are larger (smaller) for northward (southward) IMF Bz, implying a pile‐up of the magnetic flux in the first case and stronger reconnection in the second. Model distributions of the MS field magnitude reveal local depressions, associated with polar cusps near the high‐latitude limits of data coverage. Plain Language Summary: The terrestrial magnetosheath is a relatively wide transition region, separating our planet's magnetosphere from the undisturbed flow of magnetized solar wind. Due to the sudden compression of the incoming plasma flow at the bow shock and high conductivity of the magnetosheath medium, the relatively weak magnetic field of interplanetary origin undergoes abrupt compression and drapes around the magnetosphere boundary, the magnetopause. Huge amounts of archived spacecraft data accumulated in the world data centers during past decades of space flight made it possible to develop quantitative models of the magnetosheath magnetic field, based on direct in situ observations. This paper presents first results of such a modeling study, providing a closed analytical representation of the magnetosheath magnetic field, driven by input from upstream monitors of the interplanetary medium. Key Points: A closed empirical model of the magnetosheath magnetic field is developed, based on satellite data and a flexible mathematical architectureDriven by interplanetary parameters and dipole tilt, the model faithfully reproduces basic features of the IMF draping around the magnetopauseNorthward (southward) IMF results in higher (lower) subsolar fields, indicating magnetic flux pile‐up (stronger reconnection), respectively [ABSTRACT FROM AUTHOR]

We thank Lauri Holappa, Jone Peter Reistad and Anders Ohma for their interest in our research and for having published their comments, referred hereafter as HEA2023. Here we present our counterarguments to the points presented in HEA2023. We explain the observed excess of AL values for different polarities of IMF By over different IMF Bx polarities by an additional negative IMF Bz, which exist due to the 7.25‐degree tilt of the solar equatorial plane to the ecliptic plane. We emphasize again that the AL index strongly depends on the dipole tilt, so that under the same driving conditions is more than twice larger during non‐tilted dipole periods than at solstices. The IMF Bx component, depending on its polarity, moves the magnetotail plasma sheet away from or toward the equatorial plane, and thus changes the effective dipole tilt angle. That change may be a cause of the asymmetric response of the AL‐index to positive or negative values of the IMF Bx. Key Points: AL index is strongly modulated by the dipole tilt angle under the same coupling functionIMF Bx component affects the effective dipole tilt and, hence, may affect the AL‐indexThe contention that AL index is strongly modulated by the IMF By during large dipole tilt periods is not that evident [ABSTRACT FROM AUTHOR]

The warming in the first half of the 20th century in the Northern Hemisphere (NH) (early 20th century warming (ETCW)) was comparable in magnitude to the current warming, but occurred at a time when the growth rate of the greenhouse gas (GG) concentration in the atmosphere was 4–5 times slower than in recent decades. The mechanisms of the early warming are still a subject of discussion. The ETCW was most pronounced in the high latitudes of the NH, and the recent reconstructions consistently indicate a significant negative anomaly of the Arctic sea ice area during early warming period linked with enhanced Atlantic water inflow to the Arctic and amplified warming in high latitudes of the NH. Assessing the contributions of internal variability and external natural and anthropogenic factors to this climatic anomaly is key for understanding historical and modern climate dynamics. This paper considers mechanisms of ETCW associated with various internal variability and external anthropogenic and natural factors. An analysis of the findings on the topic of long-term studies of climate variations in the NH during the period of instrumental observations does not allow one to attribute the ETCW to one particular mechanism of internal climate variability or external forcing of the climate. Most likely, this event was caused by a combined effect of long-term climatic fluctuations in the North Atlantic and the North Pacific with a noticeable contribution of external radiative forcing associated with a decrease in volcanic activity, changes in solar activity, and an increase in GG concentration in the atmosphere due to anthropogenic emissions. Furthermore, this climate variation in high latitudes of the NH has been enhanced by a number of positive feedbacks. An overview of existing research is given, as are the main mechanisms of internal and external climate variability in the NH in the early 20th century. Despite the fact that the internal variability of the climate system is apparently the main mechanism that explains the ETCW, the quantitative assessment of the contribution of each factor remains uncertain, since it significantly depends on the initial conditions in the models and the lack of instrumental data in the early 20th century, especially in polar latitudes. [ABSTRACT FROM AUTHOR]

Against the background of the war in Ukraine, the COVID-19 pandemic has waned from public consciousness as the threat of the virus to health is outweighed by safety concerns during the war. Pandemic restrictions in the European region are being lifted despite low vaccination rates in Central and Eastern European countries and a lack of effective containment strategies. However, Central and Eastern European countries are influenced most by the flow of refugees from neighboring Ukraine where a triple health crisis occurs: an overloaded health system, an ongoing COVID-19 pandemic, and the war. The aim: to review the progress regarding viral surveillance technologies that use genomics, digital, and informational tools, to find the gap in the literature and formulate policy recommendations for continuing surveillance in the context of permacrisis. Unstructured search was conducted through scientific (PubMed and Google Scholar databases) and grey literature using the keywords. The paper highlights aspects of war-related problems of infectious diseases control in Europe, new challenges in healthcare connected with COVID-19 pandemic and war in Ukraine and provides discussion on the role of innovative surveillance systems in tackling infection outbreaks (with COVID-19 pandemic as an example). The paper overviews perspectives of the implementation of the discussed measures. Future COVID-19 outbreaks and new variants are possible. Complex adaptive system models, new tools, and the next level of health and digital intelligence are needed to provide timely and valuable insights. Combining lessons learned from the COVID-19 pandemic, the threat of war, and the need for continuous outbreaks surveillance, new public health and digital intelligence tools must be designed and implemented at regional, European, and global levels. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 virus, which causes coronavirus disease 2019 (COVID-19), apart from respiratory manifestations, is able to directly affect the cardiovascular system. Therefore, different from general population target values of blood pressure might be beneficial for the patients with COVID-19. The aim of this study was to investigate whether conventional blood pressure control was associated with the severity of COVID-19. From 260 patients that were hospitalised to the unit subdivision of stable patients of COVID-center between March, 2020, and December, 2020, 163 patients with confirmed infection with SARS-CoV-2 virus and hypertension were selected. The patients were distributed by hypertension control: blood pressure <140/90 mmHg (n=94) and blood pressure ≥140/90 mmHg (n=69). Routine instrumental and laboratory investigations were registered and analysed. The patients were diagnosed and treated according to national and European guidelines. The information about the control of blood pressure was taken from the patients’ medical records. The group of patients with controlled hypertension had higher prevalence of females (p=0.03), 10 years higher median of age (p<0.01) and lower frequency of obesity (p=0.04). The patients with controlled hypertension had lower median of pulmonary injury (p=0.04) and lower frequency of SpO2<92% (p=0.02). Glomerular filtration rate <60 ml/min and proteinuria were detected significantly more frequently in the patients with controlled hypertension (p=0.02). In the presented study blood pressure below 140/90 mmHg before the admission to the hospital was associated with a lower degree of pulmonary injury but with the higher frequency of nephropathy signs. Urine test and blood creatinine monitoring might be beneficial for the patients with COVID-19 and hypertension. [ABSTRACT FROM AUTHOR]

Data from the AIRS satellite infrared spectrometer and NCEP reanalysis are used to study the formation of the ozone miniholes (OMHs) and their influence on the levels of UV radiation (UVR) from May 22 to 24, 2021, in the middle and southern parts of the Volga region and the south of Urals and Western Siberia, and from March 16 to 18, 2022, in the northwest of the European Russia. These OMHs form due to the anticyclone-caused tropopause rise and the transport of ozone-depleted air masses from the subtropics. In the former period, in the OMH region with negative total ozone (TO) anomalies up to ~20% of the average values over 2003 to 2021, the positive UVR anomalies attained 40–60%, and the UV index increased from ~6 to ~8. In the latter period, in the OMH region with negative TO anomalies up to ~ −40%, the positive UVR anomalies attained 40–60%, and the UV index increased from ~1 to ~2. The UVR flux calculations with an original radiation model confirmed the UVR increase in the OMH region revealed using satellite observations. [ABSTRACT FROM AUTHOR]

Quantitative estimates are obtained for regional features of the frequency distribution of extreme temperature, precipitation, and wind anomalies in the winter months in the Northern Hemisphere extratropical zone, associated with atmospheric circulation regimes (henceforth regimes) in the Euro-Atlantic sector. Using k-means cluster analysis for the daily geopotential height fields from the ERA5 reanalysis for 1979–2021, four most characteristic winter atmospheric circulation regimes are identified in the Euro-Atlantic sector corresponding to the North Atlantic Oscillation (NAO) in the positive (NAO+) and negative (NAO−) phases, Scandinavian blocking (SCAND), and the regime with anomalously high pressure over the North Atlantic and low pressure over Europe (ATL). Trends in the frequency of occurrence and in structures of regimes are analyzed. The NAO+ and NAO− regimes turned out to be asymmetrical in spatial structure with significantly different frequencies of occurrence (33% and 19%, respectively). The associated extreme weather anomaly fields are also asymmetric. For all regimes, an asymmetric response in the frequency of occurrence of positive and negative temperature anomalies is noted. Over the period under study, no statistically significant trends are found in the seasonal average frequency of occurrence of the regimes, or in the seasonal average fields of the regimes in the region of the geopotential height anomaly extremes, probably indicating the stability of these regimes under recent climate changes. [ABSTRACT FROM AUTHOR]

We consider the problem of passive acoustic direction finding with a linear microphone array in the presence of intense interference. It is assumed that a useful signal, as well as interference, is broadband and has an arbitrary time shape. It is also assumed that interference at various microphones differs only by the delay and amplitude. Such a scenario is realized when detecting a weak acoustic source against the background of intense local source (interference). The former and the latter can be represented by a small unmanned aerial vehicle and, e.g., a helicopter, respectively. For the considered scenario, we propose an algorithm, which is based on the maximum-likelihood method in the frequency domain. The proposed algorithm is studied on the basis of numerical models using the spectra of the experimentally obtained useful signal and interference. The achievable accuracies of the noise direction finding for various parameters of the problem are obtained. [ABSTRACT FROM AUTHOR]

The existing fundamental similarities in the chemistry of structurally related carbon and silicon compounds have been demonstrated. Stable silicon analogs of ethylene, silenes or silaethylenes R2C=SiR2 and disilenes R2Si=SiR2, as well as ethyne (acetylene) analogs, disilynes RSi≡SiR, have been considered. A number of unique branched (bulky) organic and organosilicon substituents have been described; the introduction of such substituents to double- or triple-bonded silicon atoms makes it possible to protect the latter from the action of atmospheric oxygen and moisture and prevent secondary dimerization (oligomerization) processes. Examples are given of steric protection for obtaining kinetically stable unsaturated silicon compounds which were characterized by IR, NMR, and UV-Vis spectroscopy and X-ray analysis. [ABSTRACT FROM AUTHOR]

Virtually unlimited volumes of serpentine resources stimulate search for new procedures for its processing, including those involving thermal activation. Along with the calcination parameters (temperature, time), the crystal-chemical features of the initial serpentines are an important factor. They predetermine the sequence of the formation of new phases in the course of thermolysis and the content of these phases in the heat treatment product. The influence of the calcination temperature on the thermal decomposition of a serpentine mineral, antigorite, was studied by differential scanning calorimetry, X-ray diffraction analysis, and Mössbauer spectroscopy. Amorphous antigorite is not formed in the course of thermolysis, and the intermediate amorphous magnesia–silicate phase is a mixture of two dehydroxylates differing in the ability to react with acid solutions. The activity of the calcination products was determined by two different methods. The optimum calcination temperature is 750°C; it ensures the maximal content of the amorphous active magnesia–silicate phase. [ABSTRACT FROM AUTHOR]

The studies were performed with samples from different horizons of soddy podzolic soils (Albic Retisols) and typical chernozem (Haplic Chernozems) collected under natural lands and arable fields. The carbon contents in structural (particulate organic matter of 2–0.05 mm in size (CPOM) and mineral-associated organic matter of <0.05 mm in size (CMAOM)) and process (potentially mineralizable organic matter (C0) and microbial biomass (Cmic)) pools were determined. In the humus horizon of virgin and arable Albic Retisols, the CPOM, CMAOM, C0, and Cmic pools contained 38 and 24, 56 and 72, 5.9 and 5.6, and 1.2 and 1.3% of Corg, respectively. The sizes of these pools in virgin and arable Haplic Chernozems amounted to 42 and 30, 53 and 68, 3.6 and 2.8, and 0.5 and 0.5% of Corg, respectively. Despite a low weight of the POM fraction, the emission potential of CPOM pool is comparable to that of the CMAOM pool having the large MAOM fraction. A method for quantitative separation of soil organic matter (SOM) into active, intermediate (slow), and passive pools is proposed. The size of the SOM active pool is assessed according to the Сmic and C0 contents; the size of the passive pool, according to the content of chemically non-oxidizable organic matter in CPOM and CMAOM fractions. The intermediate pool size is estimated according to the difference between the total organic carbon and the sum of the active and passive pools. The active, intermediate, and passive pools of the studied soils contained 1–7, 51–81, and 13–48% of Corg, respectively, without any significant differences between different land uses. [ABSTRACT FROM AUTHOR]

Worsening safety of aircraft exposed to lightning discharges is associated, among other things, with a change in the mechanical characteristics of the alloys from which the aircraft fuselage is made. To analyze the impact of discharges on experimental samples, a current-pulse generator has been developed that simulates stages of lightning development. The results of processing the information obtained are presented and conclusions are drawn about changes in the structure and characteristics of the samples studied depending on the discharge parameters. [ABSTRACT FROM AUTHOR]

Experimental seasonal forecasts using the INM-CM5 climate model have been applied as the input data for the temperature–time phenological model of birch pollination. A test method has been developed within the framework of the joint model for the seasonal forecasting of the time of the beginning of birch pollen dispersion in the European territory of Russia. Verification of this method on seasonal retrospective forecasts of the INM-CM5 model (in 1991–2019) has shown an adequate reproduction of the days of the beginning of birch pollen season simulated for the same period based on ERA5 reanalysis. The mean systematic errors are ±2 days, and the spatial correlation coefficients exceed +0.84. The forecasts of the date of pollen dispersion beginning in 2022 simulated from the experimental operational seasonal forecasts using the INM-CM5 model with a monthly lead time and with a zero lead time are also evaluated. It is shown that the errors in forecasting the onset of pollen dispersion are ±5–10 days, with smaller errors of forecasts with a 1-month lead time. The results allow us to conclude that the seasonal forecast of the surface temperature based on the INM-CM5 model can be used as input information for the temperature–time phenological model for the operational forecast of the start time of birch pollen dispersion in the European territory of Russia. [ABSTRACT FROM AUTHOR]

The characteristics of the sea ice conditions in the seas of the Russian Arctic during the period of satellite measurements were studied, and quantitative estimates of their changes in the second half of the 21st century were obtained based on the results of the CMIP6 climate model ensemble using non-mitigation and moderate mitigation scenarios of anthropogenic impact, SSP585 and SSP245, respectively. It has been revealed that the dates of closing (DOC) of the sea ice cover and the length of the open water season (LOWS) are in general successfully reproduced by an ensemble of models. It is shown that DOC will be observed on the average about one month and ten days later under SSP245 scenario and two months later under the SSP585 scenario in 2061–2080 compared to period 1981–2020. At the same time, the increase of LOWS is more than 2.5 months under SSP245 scenario and almost four months under the SSP585 scenario. The most significant changes in DOC are expected in the northern parts of the Barents and Kara seas and in the northwestern part of the Laptev Sea: 2–2.5 months and 2.5–3 months later for the SSP245 and SSP585 scenarios, respectively. [ABSTRACT FROM AUTHOR]

Natural allylpolyalkoxybenzenes were used to synthesize polyalkoxychalcones featuring various conformations, including β-methyl-substituted S-trans-conformers and tetralone derivatives with restricted S-cis conformation. Antiproliferative antitubulin activity and cyto-toxicity of these compounds were studied using a sea urchin embryo model and human cancer cell lines. S-trans-Restricted chalcone 3y was found to exhibit high activity in the inhibition of cancer cell growth by microtubule destabilization with IC50 = 0.02–0.04 µmol L−1. [ABSTRACT FROM AUTHOR]

The action of an electron beam on crystals of tetramethylethylenediaminium nitrilotriacetate [HMe2NCH2CH2NMe2H]2+[HN(CH2COOH)(CH2COO)2]–2, ammonium heptamolybdate tetrahydrate (NH4)6Mo7O24‧4H2O, and polymeric zinc nitrilotrimethylenephosphonate trihydrate (ZnH4L‧3H2O)n, on a lamellar crystal of 2,2'-(ethylenedioxy)di(ethylaminium) trifluoroacetate CF3C(O)O‒+H3N(CH2CH2O)2CH2CH2NH3+‒O(O)CCF3, and on films of the monoethanolaminium salt of ethylenediaminetetraacetic acid [Н3NCH2CH2OH]+2[(OOCCH2)2NCH2CH2N(CH2COOH)2]2– was studied. A Tescan VEGA II electron microscope was used as an exposure tool. The microrelief was examined at magnifications from 500× to 50000×. The survey was carried out at an accelerating voltage of 20 kV and a working distance of 2–8 mm, using secondary (SE) and backscattered (BSE) electron detectors. A copper–nickel alloy and silicate glass were used as the substrate material for the films. The crystals and films were irradiated with an electron beam of various powers, forming an area 20 × 20 μm in size. At low power, the area dimensions are strictly 20 × 20 μm, and the surface remains relatively flat. An increase in the power or in the exposure time while maintaining the power causes an increase in the size by 5 to 34%. The maximum impact causes the formation of defects in the form of cracks, swellings, bubbles, holes, and craters. The elevation of the surface increases with increasing radiation dose. [ABSTRACT FROM AUTHOR]

An analysis of interannual variability in the surface air temperature of the summer season for individual regions of Russia, as well as for most of its territory between 1930 and 2020, has been performed. For the analysis, average daily air temperature data from 526 stations of the Roshydromet observation network and the ECMWF-ERA and NOAA-CIRES reanalyses are used. Based on the meteorological station's observations and on the calculated number of days with extreme temperature values, the spatiotemporal distribution of ground air temperature for some summer months and for the summer season as a whole are evaluated. It is established that, over the past 60 years, the number of days with extremely high temperatures increased by a factor of 1.5 in most of Russia, with the largest number of such days occurring in July. Both the secular records of average monthly air temperature in the summer months as well as the absolute maximum temperature are established to be extreme. For the 30-year-long periods of instrumental observations, the maximum air temperature exceeded +39°C in some regions of Russia. It is shown that abnormally hot years have been unprecedented in the history of meteorological observations in Russia in terms of both record temperature values and the duration. The temperature regime of most areas of Russia is characterized by a spatiotemporal inhomogeneity. The analysis of temporal variation of extreme air temperature values suggests that the circumpolar and high-mountain areas are characterized by a fall in temperature in the summer months, whereas the temperate climate zones and southern regions of the country undergo a rise in temperature. It is established that, at the end of the 20th century and the early 21st century, the number of days with extremely high surface air temperature increased in the territory of Russia, which may be a precondition for the occurrence of dangerous meteorological phenomena. [ABSTRACT FROM AUTHOR]

A low-energy (cold) ion population of ionospheric origin is often present in the Earth's magnetic tail alongside with a thermal (hot) ion population. The presence of cold ions introduces small-scale effects in the dynamics of magnetic reconnection owing to their small gyroradius. Hall electric fields at the reconnection separatrices demagnetize and accelerate inflowing cold ions in the direction perpendicular to the local magnetic field. Once cold ions have passed through the accelerating layer, they enter the exhaust and continue to follow regular E × B drift motion. The overlap of cold ion trajectories produces a partial ring distribution function. A simple analytical model is proposed, pointing to the regular formation of these crescent-looking distribution functions, which we denote "crescent echoes." We performed two-dimensional particle-in-cell simulations to investigate these cold ion velocity space signatures in the reconnection exhaust. We carried out the simulations with various cold ion proportions relative to the hot ion component. In the reference run with very small, but non-negligible cold ion density, the distribution functions are very close to that from the analytical model. The reference run results are contrasted with the dynamics in the cold ion-dominated plasma in which ion–ion or lower-hybrid modes might develop. We conclude that an increased density of cold ions leads to blurring of the crescent echoes into a more thermal distribution due to wave activity development. [ABSTRACT FROM AUTHOR]

The atmospheric air quality in Ufa from 2017 to 2020 is analyzed. The effect the meteorological factors have on the pollution level in this period is considered. The analysis is based on instrumental measurements at nine stations from Roshydromet state observation network. The daily values of the atmospheric pollution parameter are calculated. Trends in variations in the level of atmospheric pollution by different admixtures are determined. The method of wavelet transforms is used to determine the characteristic periods of oscillations in the pollution level. Based on the cross-wavelet analysis, relations are identified between the air pollution level and the basic meteorological parameters of the atmosphere. The average concentrations of sulfur dioxide, xylenes, and toluene increased in 2017–2020. The level of atmospheric pollution is high during calm weather, weak winds, and temperature inversions. The observed changes in urban atmospheric pollution make it possible to estimate how different anthropogenic factors influence the qualitative composition of atmospheric air. [ABSTRACT FROM AUTHOR]

The paper discusses active screen plasma nitriding (ASPN) of AISI 316 L austenitic stainless steel without the use of hydrogen. It is shown that hydrogen-free plasma nitriding with double-folded active screen provides the formation of hard diffusion layers at 570 °С. In the case of conventional plasma nitriding without the use of the active screen, the diffusion layers are obtained at 600 °С and have lower length and hardness. The increase in the ASPN process time from 30 to 360 min results in the thickness growth of the nitrided layers from 10 to 90 μm and the growth in the S phase (expanded austenite) content. The time increase of the ASPN process is accompanied by the reduction in the corrosion resistance of 316 L austenitic stainless steel. But at a relatively short process time (30 min), when the thickness of diffusion layers does not exceed 10–20 μm, the corrosion resistance even slightly improves at a simultaneous hardness growth and wear rate reduction. As a result, high-temperature and high-speed hydrogen-free plasma nitriding is demonstrated for 316 L austenitic stainless. [ABSTRACT FROM AUTHOR]