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The problem of guaranteed closed-loop guidance to a given set at a given time is studied for a linear dynamic control system described by differential equations with a fractional derivative of the Caputo type. The initial state is a priori unknown, but belongs to a given finite set. The information on the position of the system is received online in the form of an observation signal. The solvability of the guidance problem for the control system is analyzed using the method of Osipov–Kryazhimskii program packages. The paper provides a brief overview of the results that develop the program package method and use it in guidance problems for various classes of systems. This method allows us to connect the solvability condition of the guaranteed closed-loop guidance problem for an original system with the solvability condition of the open-loop guidance problem for a special extended system. Following the technique of the program package method, a criterion for the solvability of the considered guidance problem is derived for a fractional-order system. In the case where the problem is solvable, a special procedure for constructing a guiding program package is given. The developed technique for analyzing the guaranteed closed-loop guidance problem and constructing a guiding control for an unknown initial state is illustrated by the example of a specific linear mechanical control system with a Caputo fractional derivative. [ABSTRACT FROM AUTHOR]

Ground-based measurements of the vertical atmospheric electric field of the Earth sometimes show bay-like anomalies that precede some earthquakes. In some cases, these anomalies have even been accompanied by a change in the sign of the field under fair weather conditions. Possible causes of this phenomenon are typically attributed to anomalous changes in the electrical conductivity in the near-surface atmospheric layer, increased radon emission from the soil, etc. This paper proposes another mechanism of atmospheric electrical anomalies, which involves the entrainment of charged aerosols as well as light and heavy ions by air flows. Such flows can be produced due to small temperature anomalies observed before some seismic events. Theoretical analysis shows that anomalously strong electrical variations may occur even in the presence of weak air flows provided that they persist for a long time and a peculiar structure of the velocity field, which presumes vertical air circulation and particle exchange between different atmospheric layers. For this type of flows, an analytic solution is derived and spatial distributions of atmospheric electric perturbations are obtained. The results of calculations and estimates confirm that the proposed mechanism can explain the observation data. [ABSTRACT FROM AUTHOR]

Carotenoids belong to one of the most common classes of biological pigments. They are observed in either free form (dissolved in hydrophobic media) or as stoichiometric complexes with protein (carotenoproteins). An interaction between a carotenoid and a protein environment is determined mainly by the molecular conformation and dynamic behavior of a cofactor pigment. In this study, using molecular modeling methods, we have analyzed the whole set of alternative conformational states of cyclic side groups of carotenoids and evaluated the energy effects of their interaction with the conjugated backbone chain. The performed theoretical study resulted in the energy-sorted catalogue of alternative conformational states for biogenic cyclic carotenoids and their optical isomers. Conformational states described in this study can be used for a correct selection of initial conditions for the molecular modeling of carotenoproteins. [ABSTRACT FROM AUTHOR]

Abstract—It has been observed that strong earthquakes and volcanic eruptions are sometimes followed by geomagnetic oscillations with frequencies of 3.5–4.0 mHz. This paper describes the theoretical study of the probable cause of these phenomena, which is related to the vertical acoustic resonance between the Earth's surface and the thermosphere, produced by the propagation of the atmospheric wave corresponding to the acoustic branch generated by surface displacements. The propagation of two-dimensional (2D) harmonic acoustic wave is analyzed in a plane layered model of the atmosphere and ionosphere with oblique geomagnetic field. The altitude of the reflecting atmospheric layer corresponds to the region of a sharp temperature change in the vicinity of the thermosphere boundary ~80–90 km. The calculated fundamental resonant frequency is close to the observed oscillations. The obtained solution is used to calculate currents and electromagnetic perturbations in the atmosphere and ionosphere. Assuming thin-layer approximation for the ionospheric E-layer, we derive formulas describing the geomagnetic disturbances (GMD) in the ionosphere and on the Earth's surface. The GMD spectrum has a sharp peak at the frequency corresponding to the acoustic resonance. According to the calculations, close to the resonance frequency, the power spectral density of GMD on the ground can reach 5–30 nT2/Hz, which is consistent with the results of ground-based measurements. [ABSTRACT FROM AUTHOR]

The results of numerical simulation of a multiple-beam X-band klystron have been presented. The analysis of a new principle of constructing the interaction space that allows us to provide a high efficiency value without using second harmonic resonators has been given. The results of an experimental study of the developed 25-beam KIU-283 klystron with a peak power of 3.0 MW at a frequency of 9300 MHz with an electronic efficiency of 58% have been presented. [ABSTRACT FROM AUTHOR]

The production of adhesive compositions being a part of the technological complex that provides the manufacture of soundproof screens and other products with acoustic or vibration-resistant properties, consists of a number of experimental units and pilot plants. The organization of the technological process is determined by the range of manufactured products, as well as by the characteristics of the raw materials and other materials under use, which determines, to a considerable extent, the character and composition of the resulting industrial wastes. This experimental study is devoted to searching for reliable methods for water purification from the technological impurities of sulfur-containing compounds. According to the results of the experiments, based on data obtained in the course of the operation of laboratory-scale technological and industrial facilities, it has been shown that an efficient solution to the problem of water purification consists in a method of stepwise impurity removal, initially by means of an adsorption purification technique and, then, as affected by a catalytic complex based on calcium and molybdenum oxides. The production drains processed based on this method can be further disposed of with the use of standard biological wastewater treatment plants. [ABSTRACT FROM AUTHOR]

Significant degradation of the Agrakhan Bay on the eastern coast of the Terek River delta has occurred in the course of the 20th century as a result of the combined action of natural and anthropogenic factors. Comprehensive studies conducted by the authors in 2018–2020 have made it possible to describe the main causes of this degradation, characterize the current state of the reservoir, and establish scientific bases under recommendations for its improvement. It has been demonstrated that as a result of partial drying and reduction of water surface area the bay has lost its former importance as a spawning and rearing water body providing the West Caspian region with the younglings of valuable commercial fish species. By 2018, the catches decreased by ten times compared to the early 20th century with sturgeons having almost totally disappeared. The state of the northern part of the bay, which has transformed into a group of shallow water bodies almost entirely separated from each other and from the sea is particularly unfavourable. The study of hydrological and morphological, hydrobiological, fishery-related and hydrochemical parameters has shown that the improvement of the wetlands at the former bay site is possible. Detailed analysis of the water balance using multivariate limnological calculations has shown that there is enough water for watering and partial restoration of the water bodies of the Agrakhan Bay hydrographic system. Clearing of silted and overgrown canals, deepening and berming of the remaining water bodies, and directing the necessary amounts of river water into Northern and Southern Agrakhan Bay (in accordance with the calculated delivery schedule) will allow reduction of the overgrowing and siltation of water bodies, restore the water exchange between them, improve water quality, revive the fishery industry in the region, improve the habitats of many rare and protected animal species, and increase the recreational attractiveness of the region. [ABSTRACT FROM AUTHOR]

The Agrakhan Bay of the Caspian Sea is a unique hydrographic and environmentally valuable object at the mouth of the Terek River. At the beginning of the 20th century, it was a typical sea bay; however, by the 21st century, it lost the features of a marine area and a single water body and was divided into two parts with their specific hydrographic network, water regime, landscapes, biota, and anthropogenic load. Rehabilitation of the wetlands of the former sea bay requires urgent and scientifically grounded measures, as well as good knowledge of the causes and features of its rapid degradation and data on its current hydrological-morphological and hydroecological state. In 2018–2020, the authors carried out a series of field reconnaissance, geodetic, hydrometric, botanical, and hydrochemical works in this part of the mouth, created a network of stations, took numerous water samples and bottom soil samples, and analyzed them in laboratories. A vast array of data from Roshydromet (Russian Hydrometeorological Service) stations, as well as multi-temporal cartographic materials and satellite images, have been accumulated and studied; a multilayer GIS and various maps, empirical dependencies, diagrams, and graphs have been constructed; the results of studies by outside specialists have been considered. This study has made it possible to comprehensively describe the current state of the former Agrakhan Bay, build a depth map, a landscape map, a map of bottom sediments, a map of macrophytes, and a map of hydrochemical parameters, describe the water regime and water balance of the main water bodies of the former bay, determine the relationships between the main hydrological and morphological characteristics, etc. Patterns, causes, long-term stages, and parameters of the unfavorable morphodynamics of the Agrakhan Bay in the 20th century and at the very beginning of the 21st century have been studied. This has made it possible to justify measures for partial restoration of the hydrological and ecological potential of the water bodies of the former Agrakhan Bay. [ABSTRACT FROM AUTHOR]

The Arctic is warming faster than any other region on Earth. Putting this rapid warming into perspective is challenging because instrumental records are often short or incomplete in polar regions and precisely-dated temperature proxies with high temporal resolution are largely lacking. Here, we provide this long-term perspective by reconstructing past summer temperature variability at Yamal Peninsula – a hotspot of recent warming – over the past 7638 years using annually resolved tree-ring records. We demonstrate that the recent anthropogenic warming interrupted a multi-millennial cooling trend. We find the industrial-era warming to be unprecedented in rate and to have elevated the summer temperature to levels above those reconstructed for the past seven millennia (in both 30-year mean and the frequency of extreme summers). This is undoubtedly of concern for the natural and human systems that are being impacted by climatic changes that lie outside the envelope of natural climatic variations for this region. A 7,638 yr summer temperature reconstruction based on subfossil trees buried in the Siberian Arctic shows that recent warming is unprecedented and interrupted a multi-millennial cooling trend. [ABSTRACT FROM AUTHOR]

Abstract—Anomalous variations in radon emissions from the soil are sometimes observed before and after strong earthquakes. In this paper, we theoretically analyze the known hypothesis that these variations in radioactive emanations in the surface layer of the atmosphere cause variations in the vertical background current in the atmosphere with subsequent changes in the electron density in the lower ionosphere. For this purpose, we will first assess the relation between radon emission variations and the vertical atmospheric current flowing into the ionosphere. Then we will solve a model problem concerning the spatial distribution of plasma density and electric field perturbations occurring in the E-layer of the ionosphere caused by an inflowing vertical current. It was believed that the current flowing into this layer contains only an electron component and is attenuated only by the recombination of electrons. The estimate of the maximum variation is at least 3–5 orders of magnitude smaller than the observed anomalous variations, which allows us to conclude that this hypothesis is not plausible. [ABSTRACT FROM AUTHOR]

We analyze theoretically ultra-low frequency electromagnetic noise caused by deformations of seabed and porous coastal rocks subjected to incident long oceanic waves. A variable pressure on the seabed due to propagation of long gravity waves (LGWs) gives rise to variations in pore pressure gradient followed by groundwater filtration in pores and channels of porous rocks. These processes result in the generation of telluric electric currents in water-saturated porous rock of the seashore due to electrokinetic effect. In the model a displacement of the sea surface in LGWs is described in the "shallow water" approximation. A set of basic equations describing rock strain and electrokinetic effect is solved in quasi-static approximation. The telluric electric field in the porous rocks of coastal zone are found as a function of depth and distance to the coastline at different frequencies of LGWs. The theoretical analysis has shown that telluric electric noise produced by the LGW can exceed the level of natural electric noise during geomagnetically quiet period in a coastal strip about several tens of meters. [ABSTRACT FROM AUTHOR]

Abstract—Analysis of the topography and functional activity of central and peripheral monoaminergic neurons is one of the priorities of neurosciences, since these neurons play a key role in the regulation of the most important functions of the brain and internal organs. After the development of methods for detecting monoaminergic neurons in the 1960s–1980s (histo-fluorescence, immunocytochemistry), numerous studies were performed to map monoaminergic neurons and describe their phenotype. Fundamentally new opportunities for studying monoaminergic neurons have appeared in the last ten years following the synthesis of a fluorescent ligand of membrane transporters of monoamines—4-[4-(dimethylamino) styryl)-N-methylpyridinium iodide (ASP+), which allows staining of living monoaminergic neurons. Our work aimed to expand the spectrum of ASP+ use in the study of central and peripheral monoaminergic neurons. When doing this, (1) we developed a method for ASP+ staining of living dopaminergic neurons in a primary culture of the mouse embryonic mesencephalon, which can be used for testing antiparkinsonian drugs in cell models of Parkinson's disease; (2) using ASP+, we developed a method for assessing the permeability of the cerebrospinal fluid-brain barrier for monoamines and for mapping the monoaminergic neurons involved in the exchange of monoamines between the cerebrospinal fluid and the brain; (3) we showed that the systemic administration of ASP+ allows in vivo mapping of peripheral monoaminergic neurons and cells of peripheral organs expressing monoamine transporters; and (4) we showed that ASP+ cannot be used to assess the formation of the blood-brain barrier during ontogeny. [ABSTRACT FROM AUTHOR]

Methods are presented for synthesis of composite materials based on resorcinol–formaldehyde polymer and phosphorus-containing vermiculite with simultaneous introduction of calcium carbonate into the reaction mixture. The composition and structure of sorbents have been determined by IR spectroscopy, X-ray powder diffraction, scanning electron microscopy, low-temperature nitrogen adsorption, and positron annihilation spectroscopy. The sorption characteristics of the composites have been studied using the example of methylene blue adsorption and strontium extraction from aqueous solutions under static conditions. The results of strontium sorption have been calculated using the Freundlich, Langmuir, and Langmuir–Freundlich equations. The strontium distribution coefficients have been calculated at pH 6–7; it has been shown that the Kd of the sorbent with phosphorus-containing vermiculite and calcium carbonate is higher than the Kd of the known model resorcinol–formaldehyde sorbent. The degree of inhomogeneity of the sorbent surface, as well as the sorption constant and the maximum sorption value, have been determined. The dependence of the limiting sorption on the degree of inhomogeneity and the number of defects during positron annihilation (Ne+) have been demonstrated. The ionization constants and the capacity of surface functional groups have been determined by potentiometric titration. [ABSTRACT FROM AUTHOR]

We consider the problem of finding the derivative of a function, which is a classical problem of mathematical analysis. The values of the function are measured continuously over a finite time interval with some error. We propose an algorithm for the approximate calculation of a Caputo fractional derivative from the measurement values based on the methods of feedback control theory. First, the problem of calculating the fractional derivative is replaced by an inverse problem for a control system. Then the method of dynamic inversion is applied to the inverse problem, which allows us to construct a real-time solution algorithm stable under information noises and computational errors. The algorithm is based on N. N. Krasovskii's extremal aiming method, which is widely known in the theory of guaranteed control, and on a local modification of A. N. Tikhonov's classical regularization method with a smoothing functional. The order of convergence of the proposed algorithm is obtained, and a numerical example illustrating the application of the developed technique for calculating Caputo fractional derivatives of specific functions in real time is considered. [ABSTRACT FROM AUTHOR]

We proposed an approach to the creation of a flight laboratory based on an unmanned aerial vehicle for researching algorithms for processing digital images for the problem of closed-ranged photogrammetry. Information on the developed on-board optoelectronic measuring system for recording experimental images is presented. Examples of the images obtained and the results of their processing are shown. We presented the results of the measurement error estimate for the created system. [ABSTRACT FROM AUTHOR]

Abstract—In recent years, the supra-long Yamal tree-ring chronology has been significantly extended and became much more reliable. This article characterizes the sample wood used to build the longest absolutely dated Siberian Larch tree-ring chronology of the Subarctic area, i.e. from 6748 BC to 2019 AD, for a total continuous period of 8768 years. The ecological value of the temporal and spatial distribution of the dated trees are presented, and their potential use for application in various field of natural sciences and humanities are discussed. [ABSTRACT FROM AUTHOR]

The effect of electron fluxes from the Earth's radiation belts on satellites made of dielectric materials is studied theoretically. Spherical shaped nanosatellites of the BLITS and BLITS-M types are considered as a model. An analytical solution is obtained for the dependence of the electric field on the distance to the center of the satellite. Empirical formulas are used for the electron flux density and the track length in matter depending on the electron energy. The energy losses of incident electrons in the Debye shielding layer that surrounds the satellite, as well as the appearance of radiation conductivity in the surface layer of the dielectric, are taken into account. The reasons for the nonmonotonic dependence of the electric field on the satellite radius are established. Despite the fact that the electric field inside the satellite is smaller than the electrical breakdown threshold of the solid dielectric, it can be assumed that the dielectric micro-breakdown can occur in the surface layer of the dielectric and near inhomogeneities. [ABSTRACT FROM AUTHOR]

A specific formulation of the “classical” problem of mathematical analysis is considered. This is the problem of calculating the derivative of a function. The purpose of this work is to construct an algorithm for the approximate calculation of the Caputo-type fractional derivative based on the methods of control theory. The input data of the algorithm is represented by inaccurate measured function values at discrete, frequently enough, times. The proposed algorithm is based on two aspects: a local modification of the Tikhonov regularization method from the theory of ill-posed problems and the Krasovskii extremal shift method from the guaranteed control theory, both of which ensure the stability to informational noises and computational errors. Numerical experiments were carried out to illustrate the operation of the algorithm. [ABSTRACT FROM AUTHOR]

We consider the trajectory tracking problem for a dynamical system described by nonlinear fractional differential equations with an unknown input disturbance. Based on regularization methods and constructions from guaranteed positional control theory, we propose an information noise- and computational error-robust algorithm solving the problem for the case in which only part of the system parameters can be measured. [ABSTRACT FROM AUTHOR]

Transient luminous events (TLEs) such as sprites, blue jets (BJs) and elves have been studied intensively during the last three decades, and much is now known of their properties. This progress is caused by several factors including satellite optical observations, ground-based measurements of sprite-produced electromagnetic fields, the use of high-speed video observations and telescopic cameras with high resolution that enables one to trace the dynamics of sprite and BJ development. In this paper, we review various types of TLEs, including recently discovered dancing sprites, gnomes, ultraviolet (UV) atmospheric flashes and other effects. The sprite initiation, visible evolution, streamer structure, and their relationship with intra-cloud (IC) process are discussed. Considerable study has been given to ULF/ELF measurements which can provide us with important information on the delayed sprite generation and the role played by IC processes in the perturbation of the lower ionosphere above the sprite. A set of electrodynamic and transport kinetic equations describing the TLEs are complicated because the number densities, mobilities of electrons and ions, reaction constants and other parameters are strongly dependent on altitude. Because of this, the majority of theoretical study of TLEs and other large-scale optical phenomena at high altitude are based on numerical modeling of the basic kinetic, transport and electrodynamic equations describing TLEs evolution, whereas the analytical theory remains a formidable task to be accomplished. In this paper, we review a few analytical results, which have been recently derived from simple physical models of the TLEs phenomena. In the remainder of this paper, we focus our attention on the properties of UV flashes in the mesosphere, which have been observed onboard Russian microsatellites "Universitetsky-Tanyana" and "Vernov." Such a kind of optical flash is referred to as a transient atmospheric event, which differs from the TLEs in optical energy, duration and other parameters. [ABSTRACT FROM AUTHOR]

This study was aimed at evaluating the neuroprotective effect of N-docosahexaenoyldopamine (DHA-DA), an endogenous bioactive lipid of the neurolipin family, on mesencephalic dopaminergic neurons of mouse fetuses in a cell culture under exposure to 1-methyl-4-phenylpyridinium+ (MPP+), a specific neurotoxin for catecholaminergic neurons. The state of neurons in the experiment (MPP+) and in the control (0.9% NaCl) was estimated according to three parameters: the number of surviving dopaminergic neurons, the length of the neurites, and the total content of dopamine in the neurons. DHA-DA was shown to have a dose-dependent neuroprotective effect on degenerating dopaminergic neurons under the influence of MPP+. DHA-DA at concentrations of 0.5 μM or lower does not have a neuroprotective effect. However, at higher concentrations it has a neuroprotective effect, preventing the death of dopaminergic neurons and the degradation of neuritis. At a concentration of 1 μM, DHA-DA protects the neuron cell bodies from degradation to a higher extent than their processes, whereas at a concentration 2 μM it protects and/or stimulates to a greater extent the growth of processes of the surviving neurons. In addition, DHA-DA reduces significantly the loss of dopamine in neurons under exposure to MPP+. Thus, it is shown that DHA-DA has a dose-dependent neuroprotective effect on degenerating dopaminergic neurons. [ABSTRACT FROM AUTHOR]

Quasi-optimal algorithms for information processing are synthesized for navigation systems of mobile ground objects using the methods of the Markov estimation theory of random processes. The novelty of these algorithms lies in the possibility to solve the problem of detecting radio signals of satellite radio navigation systems at the input of the receiving equipment together with the problem of adaptive estimation of parameters of these signals and the problem of identifying the parameters of the model of mobile ground objects. A structural diagram of the navigation system is developed based on the synthesized algorithms. [ABSTRACT FROM AUTHOR]

In this paper we analyze theoretically the effect of geomagnetic field on rotation of passive conductive satellites of a spherical shape such as Russian-Australian satellite WESTPAC or Russian satellite Larets. The main cause of this effect is the generation of eddy currents and satellite magnetic moment, which interact with the Earth's magnetic field. The analytical solutions have been derived for orbital and intrinsic magnetic moments of satellite, which result from a translatory motion of an Earth-orbiting satellite and from a satellite spin around axes passing through its center of mass. An arbitrary relation between skin layer depth and satellite radius is assumed. Both a torque acting on satellite in geomagnetic field and the changes in its angular velocity are derived. The satellite orbiting the Earth in a circular orbit with an arbitrary tilt of the orbital plane is studied having regard to rotation of the vector of geomagnetic dipole moment. A characteristic time it takes for the angular velocity of the satellite to decrease exponentially is estimated. Peculiarities of residual irregular vibrations of the satellite angular velocity are examined. [ABSTRACT FROM AUTHOR]

The article discusses remote methods for the description of the intraseasonal dynamics of soil and vegetation moisture. The field moisture content of the soil and vegetation cover is described by an integral indicator that takes into account the moisture content of the upper soil horizon (5–10 cm), grass phytomass, and leaves of trees and shrubs. The integrated field moisture demonstrates a reliable association with the normalized differential water index (NDWI); the determination coefficient R2 reaches values of 0.91 for individual classes of tracts. The most significant factors determining the loss of moisture during the summer period are the amount of photosynthetically active phytomass, the potential influx of solar radiation during the study period, and the moisture reserve in the soil and vegetation at the beginning of the growing season. These factors describe 67% of the NDWI difference between May and August 2016 in forest areas and 89% in the steppes. The results can be used to search for fire hazardous areas in the steppes and forests, as well as for the monitoring of vineyards. [ABSTRACT FROM AUTHOR]

The conditions of Al2O3-coating deposition in a high-current discharge with an evaporating crucible anode and an additional hollow ionization-system anode are investigated. Using probe diagnostics and optical spectroscopy, it is determined that an additional hollow anode provides an increase in the ion-current density on the surface of the coatings by ~2 times and an increase in the atomic-oxygen concentration by 1.6–2.6 times. The nanocrystalline Al2O3 coatings are deposited by the method of reactive anodic evaporation and the range of operating parameters is determined within which the α-Al2O3 phase is synthesized at a temperature of 600°C. [ABSTRACT FROM AUTHOR]

For a system of nonlinear fractional differential equations, the problem of reconstruction of an unknown input action is considered. An algorithm for its solution, stable to information interference and computational errors, is proposed. This algorithm is based on regularization methods and construction of the dynamic inversion theory. Dynamic reconstruction of the input action is carried out using the residual method, which does not require introducing auxiliary model systems. [ABSTRACT FROM AUTHOR]

In the northern part of the Siberian Platform, east of the Anabar Shield, several massifs of alkaline rocks with carbonatites identified (Tomtor, Bogdo, Promezhutochnyi) and projected according to geophysical data (Bualkalakh, Chuempe, Uele) form a large alkaline–carbonatite province. The first data on the composition of alkaline rocks of the Bogdo massif indicate that the latter belong to a group of feldspathoid rocks of basic composition: rischorrites, biotite–aegirine liebenerite syenites, carbonatized pseudo-leucite nepheline syenites with symplectites, and nepheline–feldspar aggregates. Sphene grains were extracted from various rocks of the Bogdo massif, and their U‒Pb age was determined using the SHRIMP-II secondary-ion microprobe. The calculated U‒Pb age is 394.4 ± 3.2 Ma, which is similar to the age of the Tomtor massif and the age of the rocks of the Kola alkaline province. One of the reasons for the manifestation of alkaline plume magmatism on this territory may be the effect of the peripheral zone of the African Large Low Shear Velocity Province ("Tuzo") on the Baltic area and Siberia during the Devonian age. [ABSTRACT FROM AUTHOR]

Nigrostriatal dopaminergic neurons (DNs), involved in the regulation of motor function, are characterized by a high plasticity. Indeed, at the death of up to 50% of DNs in Parkinson's disease, the survived neurons provide normal regulation. This study was aimed to determine whether the vesicle cycle proteins, syntaxin Ia (Syn Ia), synaptotagmin I (Syt I), Rab5a, and complexins I and II (Cmpx I and II) are involved in the mechanisms of neuroplasticity in the substantia nigra, which mainly contains cell bodies and processes of the DNs. In the neurotoxic models of Parkinson's disease in mice, it was shown that, at the degeneration of up to 50% of DNs, the content of Syt I, Syn Ia, and Cmpх I and II, involved in vesicle exocytosis, does not change in the substantia nigra as a whole but is compensatorily increased in individual survived DNs. Thus, the data obtained in this study suggest that the impairment of motor behavior, which occurs at the death of half of the nigrostriatal DNs, is not caused by the impairment of the production of vesicle cycle proteins in the survived DNs. [ABSTRACT FROM AUTHOR]

The paper theoretically studies the process of formation of volume charge in a spacecraft body under action of electron fluxes of Earth's radiation belts and other cosmic particles, as well as the generation of induction currents caused by geomagnetic variations. The BLITS and BLITS-M satellites, which have a spherical configuration manufactured entirely of dielectric materials as well as the metal WESTPAC satellite, are considered. The relative simplicity of the form of a dielectric satellite allows one to obtain an analytical solution to the problem and calculate the distribution of fields and charges inside and on its surface. This solution shows that after the establishment of the stationary mode, charges accumulate mainly in a narrow layer near the satellite surface. According to the obtained estimates for low orbits, the electric field strength in this layer is below the threshold value corresponding to the breakdown of uniform dielectric in laboratory conditions. Nevertheless, one can expect the appearance of local electrical breakdowns and microdestructions in the dielectric during increasing solar activity accompanied by an increase in cosmic-ray fluxes. From this point of view, space experiments, in which dielectric destruction was observed during long-term exposure to radiation, can be interpreted as the result of accumulation of microdestructions similarly to fatigue destruction of materials under long-term load. For passive satellites similar to WESTPAC manufactured of conductive materials, the magnetic moment of induction currents in the spacecraft body is estimated. According to these estimates, the interaction of this moment with the geomagnetic field leading to the precession of the axis of the satellite's rotation is most significant for Pc5 geomagnetic pulsations. [ABSTRACT FROM AUTHOR]

For a controlled dynamical system described by nonlinear fractional differential equations, we consider the problem of dynamic reconstruction of an unknown disturbance from approximate measurements of the trajectory. For this problem, we construct an algorithm based on Krasovskii's extremal shift method and find its convergence rate. [ABSTRACT FROM AUTHOR]

The mechanism of the generation of the geomagnetic field disturbance accompanying tsunami wave propagation is considered. Electric currents in the marine environment and the ionosphere are the source of the disturbance. The current in the marine environment arises as a result of its motion in the tsunami wave, while the current in the ionosphere occurs due to the occurrence of an acoustic-gravity wave (AGW) propagating from the atmosphere on the ionosphere. The source of the AGW is the vertical displacement of the surface of the marine environment during tsunami-wave propagation in it. Although the ionospheric conductance is significantly smaller than the conductivity of the marine environment, the current value in it may considerably exceed the current value in the marine environment due to the exponential growth in the AGW amplitude during AGW upward propagation. The spatial distribution of a disturbance in the induction of the magnetic field of electric currents flowing in the marine environment and in the ionosphere is obtained with allowance for their mutual inductance. It is shown that the generation of the ionospheric electric current considerably changes the characteristics of the geomagnetic field disturbance induced by a tsunami wave. Calculations have demonstrated the possibility of space monitoring of tsunami waves with the use of satellites to record disturbances of the geomagnetic field. [ABSTRACT FROM AUTHOR]

Methods of producing intermetallic compounds of p and d metals are reviewed. [ABSTRACT FROM AUTHOR]

An algorithm for designing AC generators based on class E amplifiers for inductive powering systems of batteryless implants was proposed. Parameters of three different inductive powering systems were calculated using the suggested algorithm. Each system used a pair of symmetric antennas with inductances of 3.4, 7.29, and 12.27 μH, respectively. The energy transfer efficiency and the output power of the inductive powering system based on class E amplifier were calculated as functions of the axial distance between the transmitter and the receiver for each of the three antenna pairs. The efficiencies of the systems built around antennas with inductances of 3.4 and 7.29 μH were found to be higher than 90% for axial distances in the range from 10 to 25 mm. It was found that the class E amplifier should be tuned at the minimum rather than the medium distance between the antennas. [ABSTRACT FROM AUTHOR]

Investigations were carried out concerning the influence of modifying additives on the formulations of carbamide formaldehyde resin of CFR-KhTP grade, used for the development of the noise-absorbing materials. The qualitative interdependence of the speed reduction of the formulations' thermal curing on the amount of introduced modification agent was found. The preliminary results showed the application potential of the tetramethylthiuram disulfide as the modifying agent of the carbamide formaldehyde resin. [ABSTRACT FROM AUTHOR]

A device for wireless powering of battery-free implants with 500-mW power consumption is considered. The design of the device is described. The device provides relatively high stability of operation (power drop less than 10%) in the case of coil misalignment typical of medical applications (up to 20 mm). The results of engineering tests and tests with a tissue-like phantom (isotonic solution) are presented. [ABSTRACT FROM AUTHOR]

A labeled norepinephrine analogue was prepared by bromination of norepinephrine with subsequent debromination with tritium or deuterium gas. The yield of tritiated norepinephrine was 10-20% with a molar radioactivity of 27 Ci/mmol. The biological activity of tritiated norepinephrine was evaluated by analyzing its specific capture by noradrenergic neutrons in thick sections of the brainstem and midbrain of Wistar rats, and in a suspension of cells of pheochromocytoma PC12 expressing the membrane transporter of norepinephrine. It is shown that tritium-labeled norepinephrine synthesized by the proposed method does not differ in biological activity from the natural norepinephrine. [ABSTRACT FROM AUTHOR]

We analyze theoretically two possible sources of co-seismic electromagnetic response to the propagation of various types of seismic waves caused either by the electrokinetic phenomena or geomagnetic inductive effect. The differences between these two generation mechanisms have been examined for different types of seismic waves (P, S, and Rayleigh-Love). Theoretical relationships describing the dependence of the co-seismic signal amplitude, polarization and apparent impedance on the earthquake seismic moment and magnitude have been derived as a function of distance. We indicate an observational possibility to discriminate seismo-electrokinetic and seismo-magnetic effects and to estimate their contribution into a recorded co-seismic electromagnetic signal. Magnitudes and polarization of these signals are shown to depend strongly on the type of seismic wave and local crust parameters, such as streaming potential coupling coefficient, conductivity, inhomogeneity, etc. Co-seismic electromagnetic signals, though not directly applied for earthquake prediction, contain a useful information on local crustal phenomena, and can be used to identify “sensitive” zones perspective for the monitoring of precursory electromagnetic disturbances. [ABSTRACT FROM AUTHOR]

The effect of the symmetrical coil couple geometry on the value of lateral coil misalignment that corresponds to zero coupling in inductive energy transfer systems was studied. It was shown that the distance between coil turns and the number of coil turns have rather small effect on the zero-coupling distance. Increasing the outer diameter of the coils was shown to be the only way to increase the zero-coupling distance at given parameters of the system. It was found that changes in the outer diameter of the coils had more significant effect on the zero-coupling distance when the outer diameter was more than twice as great as the inner diameter. [ABSTRACT FROM AUTHOR]

We study the external magnetic-field perturbations caused by flows of a conducting incompressible liquid which streamlines a dielectric sphere moving in it. An analytical solution of the problem is obtained for the case of a potential flow of liquid and an arbitrary orientation of the external magnetic field. Angular distribution of the magnetic and electric field perturbations, as well as the dependence of their amplitudes on distance, are examined. The directions in which the magnetic and electric components of the perturbations are the maximum are determined. Temporal dependences and the spectra of electromagnetic signals are analyzed for different parameters of the problem. The results of analytical research are illustrated by numerical calculations. [ABSTRACT FROM AUTHOR]

The control-package method is applied to solve the problem of constructing guaranteed positional guidance for a linear control dynamical system with a delay under incomplete information about the initial state. The problem is solved for the case when the initial state is contained in a compact functional set. A solvability criterion and a method for the construction of a guidance program package are proposed. The proposed procedure is applied to a particular linear control system of delayed differential equations. [ABSTRACT FROM AUTHOR]

The problem of guaranteed closed-loop guidance by a given time under incomplete information on the initial state is studied for a dynamical control system with delay by means of the method of open-loop control packages. A solvability criterion is proved for this problem in the case of a finite set of admissible initial states. The proposed technique is illustrated by a specific linear control system of differential equations with delay. [ABSTRACT FROM AUTHOR]

The subject of the present study is a tubular fractionating tower in which the heat exchange pipes and the intertubular space together function as contact devices, while the process of fractionation itself occurs in the film mode; the tubular space fulfills the functions of a stripping section, while the intertubular space serves as a rectifying section and condenser for use in the formation of distillate. As a result of mass transfer, the steam phase is enriched with low-boiling components and the liquid phase with high-boiling components. The study is designed to develop methods of calculating and simulating processes in a fractionating tower with integrated heat exchange. Through the use of the results of the study, the energy consumption and metal content of the equipment may both be reduced. [ABSTRACT FROM AUTHOR]

A game control problem for a parabolic differential equation with memory is considered. An algorithm for its solution based on Krasovskii's method of extreme shift and the method of stable paths is proposed. [ABSTRACT FROM AUTHOR]

Abstract: The improvement in the mechanical properties of PMS-1 copper powder under the action of low-pressure high-frequency induction-discharge plasma is considered. [ABSTRACT FROM AUTHOR]

The conditions for the nucleation of stress corrosion cracks in linear and compressor station gas pipeline sections were considered. The potential for the use of pipes with a smaller diameter and a thicker wall in compressor station pipelines to create favorable stressed state conditions that promote the arrest, etching, and stabilization of stress corrosion cracks was shown. The fractographic inspection of pipe fragments with stress corrosion cracks allowed us to reveal an overload that was unrelated to the increase in the internal pressure of the given gas pipeline section. This overload was a major cause of such events as the reinitiation and propagation of stress corrosion cracks to a depth of nearly 50% of the pipe wall thickness. The overload itself was presumably caused by a construction factor connected with the position of a pipe on a pipeline route and its possible deformation (pinching) owing to soil and thermal instabilities. [ABSTRACT FROM AUTHOR]

It is shown that the monitoring of the stressed state of pipelines with the use of a method based on the evaluation of magnetic properties of a pipe metal allows one to solve completely the problems of improving the reliability of a pipeline system of compressor shops, namely, evaluate the stressed state of pipelines, to detect stress concentration zones, monitor the change of stresses in a construction just during the repair of a pipeline and adjustment of pipeline supports, and optimize the character of the reduction in the stress level. [ABSTRACT FROM AUTHOR]

Due to the increased operating time of operated compressor stations (CSs) and the current safety requirements, the engineering state of the pipelines of CSs must be surveyed to confirm the possibility of their further operation (extension of the operating life). The available factual material shows that the failure of an operated pipeline is either directly related to the effect of an unrated static or dynamic load that was the primary reason for the failure or is due to the presence of flaws that facilitate the appearance of an unrated load. The presence of an enhanced level of stresses may be a consequence of several factors, including errors in design; violation of the rules of assembly of structural elements; and operating conditions related to variation in the height positions of pipeline segments due to soil instability or subsidence and also due to buckling of supports. The latter factors are traditionally indicated as probable causes of overload for pipelines located in northern regions that are located on sandy soils and under conditions of deep freezing of soils. An evaluation of the actual level of stresses of production pipelines of compressor stations (CSs) and a comparison of the parameters of the stressed states of CSs located in different regions enables one to assess the effect of climatic factors on the operating conditions of pipelines. In this study, based on an analysis of the parameters of the stressed state obtained using magnetic methods for measuring stresses, the load level of pipelines is assessed on a scale from individual segments of a pipeline to a comprehensive assessment of plant piping. [ABSTRACT FROM AUTHOR]

Advances in the development of in-tube nondestructive testing (INT) have allowed obtainment of comprehensive quantitative information that concerns the state of an operational gas pipeline at the moment of inspection and characterizes the quantity, location, and dimensions of flaws. By means of repeated testing, it is possible to assess changes in the state of an operational gas pipeline during the time period between inspections, thus showing the dynamics of corrosive damageability on the time scale and under conditions of commercial operations (within the limits of sensitivity and resolution of the flaw detectors used). In this study, the INT results for a segment of a multistrand pipeline from the Krasnotur’ insk compressor station to the Lyaly a compressor station collected in 2000–2004 with ДMT-1400 and ДMTII-1400 magnetic-pig flaw detectors are considered. On the basis of the analysis of the INT results characterizing the development of corrosion and stress-corrosion damageability at the moment of inspection, the possibilities and conditions for the use of the obtained data for comparative assessment of the changes in corrosion-related damageability of gas pipelines are considered. According to the collected information, there is no evidence that stress-corrosion damageability is enhanced during the period between two inspections and that corrosion and stress-corrosion damageability are superimposed (observation of etched longitudinal grooves during second inspection). [ABSTRACT FROM AUTHOR]

The possibility of assessing parameters of a stressed state from changes in magnetic properties is considered. Such an option would allow determining the sign and magnitude of the effective stresses. Generalized indicators of the stress state of a pipe’s cross section may include data on maximum, minimum, and average “pointlike” stress in the investigated cross section, the amplitudes of extreme values, and the average stresses in the segments of the investigated cross section. It is shown that application of such generalized characteristics of a pipeline’s stress state allows one to sequentially change the scale (selection) of the evaluated segment and compare technological-equipment units through the use of the advantages of the local testing of stresses in combination with averaged parameters of a pipeline’s segment that has a respective scale. [ABSTRACT FROM AUTHOR]

Magnetic nondestructive testing techniques were used to inspect and estimate the level and distribution of residual circular stresses in tubes used in construction of main gas pipelines in the initial state before operation. Tests were carried out on two double-seamed tubes of dimensions 1420 × 15.7 mm and 1420 × 18.7 mm and on two single-seamed tubes of dimensions 1420 × 15.7 mm, including stress measurements in three cross sections for each tube. [ABSTRACT FROM AUTHOR]