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Nemertea is a phylum of bilaterally symmetrical, coelomate, unsegmented worms, also known as ribbon worms. Most species of the phylum Nemertea are marine predators that contain toxins in the single-celled glands of the proboscis and/or integument. Recent transcriptomic studies have shown that nemerteans from all taxonomic groups possess a wide range of putative protein and peptide toxins, while the proteomic data for these animals are highly limited. In this study, proteotranscriptomic analysis was used to investigate the major protein components of the poison of the nemertean Kulikovia alborostrata. We identified 146 transcripts of putative toxins in the transcriptome of K. alborostrata and five putative toxins among the secreted proteins and peptides of the mucus of the animal. The expression levels of cysteine-rich peptides found in the mucus with similarity to known toxins were evaluated in different parts of the body of the worm by quantitative real-time PCR. The high level of expression of investigated peptides in the integument indicate the protective function of these toxins. Overall, this supports the idea that the mucus of nemerteans is a valuable source of peptide and protein toxins.

Diode-pumped multi-mode graded-index (GRIN) fiber Raman lasers provide prominent brightness enhancement both in linear and half-open cavities with random distributed feedback via natural Rayleigh backscattering. Femtosecond laser-inscribed random refractive index structures allow for the sufficient reduction in the Raman threshold by means of Rayleigh backscattering signal enhancement by +50 + 66 dB relative to the intrinsic fiber level. At the same time, they offer an opportunity to generate Stokes beams with a shape close to fundamental transverse mode (LP01), as well as to select higher-order modes such as LP11 with a near-1D longitudinal random structure shifted off the fiber axis. Further development of the inscription technology includes the fabrication of 3D ring-shaped random structures using a spatial light modulator (SLM) in a 100/140 μm GRIN multi-mode fiber. This allows for the generation of a multi-mode diode-pumped GRIN fiber random Raman laser at 976 nm with a ring-shaped output beam at a relatively low pumping threshold (~160 W), demonstrated for the first time to our knowledge.

Results of designing the specialized RF elements library intended for use in the CMOS 180 nm process are presented. The RF library includes a set of RF MOSFETs for amplifiers and switches design, three types of varactors based on the MOS-structure, spiral inductors, MIM-capacitors and other elements. The RF library is intended for use in combination with CAD Cadence Virtuoso IC and is focused on designing a set of amplifiers, frequency oscillators and convertors, controlled attenuators and phase shifters microwave IP-blocks of the transceiver VLSI. A test chip is developed with using the presented RF library, focused on conducting research by probe methods and containing 13 types of basic elements and specialized structures for the RF characterization of the domestic CMOS 180 nm process.

Abstract The disorder‐to‐order (crystallization) process in phase‐change materials determines the speed and storage polymorphism of phase‐change memory devices. Only by clarifying the fine‐structure variation can the devices be insightfully designed, and encode and store information. As essential phase‐change parent materials, the crystallized Sb–Te binary system is generally considered to have the cationic/anionic site occupied by Sb/Te atoms. Here, direct atomic identification and simulation demonstrate that the ultrafast crystallization speed of Sb–Te materials is due to the random nature of lattice site occupation by different classes of atoms with the resulting octahedral motifs having high similarity to the amorphous state. It is further proved that after atomic ordering with disordered chemical occupation, chemical ordering takes place, which results in different storage states with different resistance values. These new insights into the complicated route from disorder to order will play an essential role in designing neuromorphic devices with varying polymorphisms.

The high level of power supply and technical provision of logging, along with advanced technologies, ensure the enterprise’s competitiveness. The current state of facilities and resources at forestry institutions in the regions is, as a rule, unsatisfactory. Significant engineering and technological backwardness of facilities and resources is due to the specifics of the modern structure of the forest sector. With the purpose of ensuring the production effectiveness of forestry institutions in the regions on the basis of increasing the level of power supply and technical provision for logging, it is necessary to carry out appropriate research. The methods for assessing the forest as an ecosystem are a relevant area of theoretical and applied research. There are 3 basic methods used in world and Russian practice in the assessment of natural resources: comparative, cost, and income. The methodology of cost estimate for natural resources provides a flexible system of indices, which allow assessing natural resources depending on the amount of available information and practical purposes. In terms of spatial economics we propose to develop a pilot project to improve the efficiency of production in the state autonomous forestry institutions of the Republic of Bashkortostan. The project is intended to provide practical guidance on the allocation of 2–3 groups of forestry institutions. We used an expert approach to assess the rating of forestries. Our earlier estimates for forestry enterprises in the Republic of Bashkortostan (state autonomous institutions) were used as the basis for it. The values of quantitative criteria include expert estimates and statistical information from numerous sources, such as reports, handbooks, results of surveys, interviews, etc. The criteria were divided into 2 groups: quantitative (availability of logging equipment, transport accessibility, calculated logging area) and qualitative (state of the logging equipment, repair depot, and management structure). According to the results of the integral assessment, the forestries are divided into 4 groups. Based on the assessment performed, it is advisable to identify the points of growth in the pilot project of modernization the facilities and resources of forestry enterprises. For citation: Konshakova S.A., Bulkhov N.A., Zaikin A.N., Kuznetsov S.G., Sivakov V.V. Assessment of the Development Potential of Forestry Enterprises of the Republic of Bashkortostan. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 202–214. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-202-214

Multimode fibers are attractive for high-power lasers if transverse modes are efficiently controlled. Here, a dielectric thin-film mirror (R~20%) is micro-fabricated on the central area of the end face of a 1 km multimode 100/140 µm graded-index fiber and tested as the output mirror of a Raman laser with highly multimode (M2~34) 940 nm diode pumping. In the cavity with highly reflective input FBG, Raman lasing of the Stokes wave at 976 nm starts at the threshold pump power of ~80 W. Mode-selective properties of mirrors with various diameters were tested experimentally and compared with calculations in COMSOL, with the optimum diameter found to be around 12 µm. The measured Raman laser output beam at 976 nm has a quality factor of M2~2 near the threshold, which confirms a rather good selection of the fundamental transverse mode. The power scaling capabilities, together with a more detailed characterization of the output beam’s spatial profile, spectrum, and their stability, are performed. An approximately 35 W output power with an approximately 60% slope efficiency and a narrow spectrum has been demonstrated at the expense of a slight worsening of beam quality to M2~3 without any sign of mirror degradation at the achieved intensity of >30 MW/cm2. Further power scaling of such lasers as well as the application of the proposed technique in high-power fiber lasers are discussed.

Introduction. Until relatively recently, all carbonate rocks have been divided into organogenic and chemogenic rocks. The former group includes those half-composed of skeletal remains, thus representing a biological problem. The group of chemogenic carbonate rocks initially included all carbonate rocks with a crystalline structure. Later, the “chemogenicity” of formation was attributed only to pelitomorphic and microgranular varieties, while pure crystalline structures were recognised as the result of secondary recrystallization. However, the purely chemical precipitation of carbonate material from ocean waters by exceeding the solubility limit appears to be impossible. It occurs either biogenously during the formation of carbonate skeletons or biochemically as a result of changes in the acidity or alkalinity of the medium. The latter is typically implemented due to a carbonate disequilibrium between, on the one hand, the dissolved bicarbonates of calcium and magnesium and, on the other, water-dissolved carbon dioxide. The removal of the latter by photosynthetic organisms disturbs the dynamic balance and leads to an increased alkalinity and precipitation of carbonates, firstly calcium and then magnesium ones at higher pH values. Along with plants, microbial communities perform a similar function.Aim. The paper presents the results of generalization and systematization of accumulated research data on the abovementioned forms.Materials and methods. In addition to literature materials, carbonate rocks of various ages — from the Vendian and Lower Cambrian of the Siberian platform to the Crimea Neogene and sediments of contemporary oceans — were examined using macro- and microscopic (mainly) methods of studying and describing specific objects.Results. Сoccoid, tubular and fibrous formations, i.e. particular bacterial “skeletons”, represent one precipitation form. At the same time, bacterial communities produce glycocalyx, representing an extracellular polymer substance, which forms a basis for submicroscopic precipitates of carbonate minerals. In this case, specific sheet- and plate-like carbonate material precipitates can be formed. The environments for implementing such mechanisms are highly diverse. Microbiolites can be formed in water bodies, including from fresh to substantially and even abnormally saline waters, in suspended matter and at the bottom of basins, both at the stage of sedimentation and during further diagenetic processes. The most famous example of the latter are various nodules.Conclusions. The processes of sediment formation and material deposition are somewhat different. The formation of a solid phase is determined by the biochemical activity of microbiota and, first of all, the creation of geochemical conditions that contribute to the appearance of a solid carbonate material. However, the fixation of this material in a sediment is implemented either in “skeletal” ball-shaped (coccolites) and tubular (tubiphytes) forms, or by precipitation as a result of absorption on glycocalyx, or by the formation of various — both isolated individual (thrombolite microclusters, oolites and oncolites) and laminar (stromatolites) — forms.

Introduction. Concepts describing bacterial effects on mineral formation and, first of all, on the formation of carbonate deposits, started to appear late in the 19th century both in Russia and globally. The precipitation of materials was demonstrated to take place directly at the sedimentation stage and continue in the formed precipitate during diagenetic processes. Research in this direction has recently intensified. Rocks and their constituent parts formed as a result of bacterial activity have been referred to as “biosedimentary structures” or “microbiolites”.Aim. The paper presents the results of generalization and systematization of accumulated research data on the abovementioned forms.Materials and methods. In addition to literature materials, carbonate rocks of various ages – from the Vendian and Lower Cambrian of the Siberian platform to the Crimea Neogene and sediments of contemporary oceans – were examined using macro- and microscopic (mainly) methods of studying and describing specific objects. Article 1 considers the main morphological types of such carbonate formations, both in the form of individual structural components of sedimentary rocks and rocks themselves with peculiar structural characteristics.Results. Two main morphological groups of carbonate microbiolites were identified and characterized. The first group represents individual and independent forms of carbonate material, both of calcite, highly magnesian-dolomite and even pure magnesite composition. This type includes mineralized precipitates of bacterial forms represented by coccolites, tubules, filaments, as well as by plate and sheet structures – mineralized glycocalyx traces. In addition, this group features isolated carbonate objects, familiar to lithologists, including oolites, oncolites, microclusters of pelitomorphic carbonate materials, thrombolites and, apparently, such specific formations as tubiphytes, etc. The second group includes laminated forms of stromatolites with their specific internal structure, as well as mineralized microbial films and mats with a complex structure, etc.Conclusions. In the overwhelming majority of cases, microbiolites are formed at the sedimentation stage, and their morphology and type are determined by specific paleogeographic and paleoclimatic conditions.

The paper describes the method that makes it possible to set up aeroballistic tests to study the aerodynamic characteristics of high-speed objects in conditions where there is an intense self-illumination (solid light) of the object. At the same time, the accuracy of external photogrammetric measurements of the spatial linear coordinates of the center of mass that meets the requirements of aerodynamic testing is provided.

The paper describes ballistic test site equipment used for studying the physical and mechanical properties of materials exposed to intense dynamic loads. To study the properties of shock-compressed substances, explosive shock wave generators based on powerful condensed explosives are used. The methods of dispersal of the used strikers in different throwing modes with different types of guns are briefly described. The methodological development in cannon experiments on light-gas guns is given, in which the conditions of safe acceleration of the strikers in the barrels of the guns and the loading parameters of the latter which provide the required collision speeds of the striker and the target are confirmed. Numerical and experimental results of testing the selected throwing modes are presented.

Abstract Multimode fibres provide a promising platform for boosting the capacity of fibre links and the output power of fibre lasers. The complex spatiotemporal dynamics of multimode beams may be controlled in spatial and temporal domains via the interplay of nonlinear, dispersive and dissipative effects. Raman nonlinearity induces beam cleanup in long graded-index fibres within a laser cavity, even for CW Stokes beams pumped by highly-multimode laser diodes (LDs). This leads to a breakthrough approach for wavelength-agile high-power lasers. However, current understanding of Raman beam cleanup is restricted to a small-signal gain regime, being not applicable to describing realistic laser operation. We solved this challenge by experimentally and theoretically studying pump-to-Stokes beam conversion in a graded-index fibre cavity. We show that random mode coupling, intracavity filtering and Kerr self-cleaning all play a decisive role for the spatio-spectral control of CW Stokes beams. Whereas the depleted LD pump radiation remains insensitive to them.

This work analyses the development of reefs, which represent thick morphologically expressed carbonate massifs created by the activity of frame-forming organisms. Major stages in the development of reefs include the periods of Early Cambrian, Ordovician, Silurian-Devonian, Late Viséan-Serpukhovian and Permian, the upper boundaries of which are generally determined by mass extinction events.The main reef builders during the Early Cambrian were archaeocyatha and epiphytaceans, while Ordovician reefs were created by sponges, stromatoporoids, tabulata and bryozoans. Stromatoporoid, tabulata, rugose and, to a lesser extent, bryozoans were the reef builders during the longest Silurian-Devonian period. Bryozoans and corals served as the frame-forming organisms for Upper Viséan-Serpukhovian reefs. However, during the Permian, reefs were built primarily by sponges and, to a lesser extent, by bryozoans and corals.It is shown that there is no strict correspondence between the termination of reef formation and the beginning of extinction events. During extinction periods, potential reef builders did exist, although beyond the reef biocoenosis structure. Similarly, the beginning of reef formation occurs somewhat later than the appearance of the corresponding frame-forming organisms. Apparently, it takes time for organisms to develop such a biocoenosis that could trigger the formation of reef ecosystems. Reef ecosystems are stable under relatively constant external conditions, changes in which cause first the degradation of the biocoenosis and then the extinction of its constituent organisms. Therefore, the process of reef formation is terminated before the actual extinction of organisms.

Light propagation in multimode fibers is known to experience various nonlinear effects, which are being actively studied. One of the interesting effects is the brightness enhancement at the Raman conversion of the multimode beam in graded index (GRIN) fiber due to beam cleanup at Raman amplification and mode selective feedback in the Raman laser cavity based on fiber Bragg gratings (FBGs) with special transverse structure. It is also possible to explore random distributed feedback based on Rayleigh backscattering on natural refractive index fluctuations in GRIN fibers, but it is rather weak, requiring very high power multimode pumping for random lasing. Here, we report on the first realization of femtosecond pulse-inscribed arrays of weak randomly spaced FBGs in GRIN fibers and study Raman lasing at its direct pumping by highly multimode (M2~34) 940-nm laser diodes. The fabricated 1D–3D FBG arrays are used as a complex output mirror, together with the highly reflective input FBG in 1-km fiber. Above threshold pump power (~100 W), random lasing of the Stokes beam at 976 nm is obtained with output power exceeding 28 W at 174 W pumping. The beam quality parameter varies for different arrays, reaching M2~2 at the linewidth narrowing to 0.1–0.2 nm due to the interference effects, with the best characteristics for the 2D array.

Crystalline transition-metal chalcogenides are the focus of solid state research. At the same time, very little is known about amorphous chalcogenides doped with transition metals. To close this gap, we have studied, using first principle simulations, the effect of doping the typical chalcogenide glass As2S3 with transition metals (Mo, W and V). While the undoped glass is a semiconductor with a density functional theory gap of about 1 eV, doping results in the formation of a finite density of states (semiconductor-to-metal transformation) at the Fermi level accompanied by an appearance of magnetic properties, the magnetic character depending on the nature of the dopant. Whilst the magnetic response is mainly associated with d-orbitals of the transition metal dopants, partial densities of spin-up and spin-down states associated with arsenic and sulphur also become slightly asymmetric. Our results demonstrate that chalcogenide glasses doped with transition metals may become a technologically important material.

A dissipative soliton mode-locked Yb-doped fiber laser is investigated experimentally and numerically from the point of view of generating ultra-broadband ultrashort pulses. An energy up to 2.2 nJ and a spectral bandwidth over 60 nm (at the −10 dB level) were obtained experimentally without dispersion compensation in the cavity. Almost a 100-fold compression coefficient has been achieved, so the resulting pulse duration was 149 fs. The numerical simulation has shown that a further scaling up to 3.5 nJ and a 100 nm spectral bandwidth is possible by reducing the low power transmission coefficient of the NPE-based SAM and increasing the amplification. At the same time, the tolerance of the SAM to a low power radiation is responsible for the transition to a multi-pulse operation regime.

Development of a method for calculating the optimal mode of conducting a train in terms of energy saving meet the safety requirements and schedules. The method of calculation must solve the assigned tasks without significant time spent on the calculation. To implement this method of calculation was used a simplified model of the train as a controlled system. The existing mathematical and algorithmic methods for solving isoperimetric problems of finding the optimal solution in the presence of restrictions on resources were the information base for methodology development. Scientific works of domestic and foreign scientists, professional periodicals, materials of scientific and practical conferences, methodical and normative materials, currently in force on Ukrainian Railways. The results of these studies were used to create simulators on the basis of computer technology for the training of locomotive drivers. The scientific novelty of the proposed calculation method consists in applying the simplified calculations of the status of the train as a controlled system, without the use of differential equations of motion that allows to significantly increase the speed of the calculations. This, in turn, will solve the problems of finding optimal control in real time, taking into account changing conditions during the movement of the train. The practical significance of the obtained results is the use of such a calculation method that does not require significant time for its implementation and can be used as a subsystem of the on-board train control system capable of per-forming calculations taking into account changes in the current train situation.

There are five great cycles of reef formation in Paleozoic — Early Cambrian, Middle—Late Ordovician, Silu-rian—Devonian, Late Visean—Serpukhovian and Permian. Their upper limits are determined by the corresponding periods of biotic crises and mass extinction events which have been at the borders of the Middle—Late Cambrian, Or-dovician—Silurian, Frasnian—Famenian, Serpukhovian—Baskirian, Permian—Triassic. Cycles differ in the reef prevalence within the planet, in the composition and group diversity of reef-building biota and the duration of reef formation. The longest Silurian—Devonian and Permian cycles are divided with periods of relative decrease in the intensity of reef building into two parts and these periods are clearly observed. These are second order cycles. The bases of this division are global paleogeographic and paleoclimatic causes, and at the beginning of Devon, perhaps, in addition to these reasons, an important role was played by the global biotic event — the appearance of terrestrial biota and, accordingly, a certain redistribution of the flow of nutrients from the ocean to land. In all cases, third-order cycles have been established, the formation of which is determined by purely regional-geological reasons, such as sea level fluctuations, salinity of basins, which are fixed by the overlap of reefs with terrigenous, clay or saline rocks. Similar role is played by the volcanism, as explosive activity stops the growth of reefs.

Subject of research. The upper Permian reefs of the Yangtze block of southern China are considered. Among them there are two species which differ in location in the basin and the nature of the internal structure.Methods and results. On the basis of geological and lithological methods of research it is shown that the main rift builders were a variety of sponges, whith a lesser extent bryozoans and wide development of non-carcass organisms. Along with relatively simple buildings (biostromes), the reefs in the strict sense of this term are also established. The beginning of reef formation is fixed by the accumulation of detritus of echinoderms with micro-grain cemented material. Reef formation ended until the end of Permian, before bulk biota extinction on the border of Permian and Triassic although potentially reef-building organisms still existed.Conclusion. The events that led to the great mass extinction were preceded by certain changes, which primarily destroyed the system of reef biocenosis, which led to the cessation of the formation of reefs with the continued existence of individual groups of organisms.

The article refers to the review and analysis of Russia’s relations with Central and East Asian countries, special attention is paid to understanding the prospects of future cooperation, especially in economic and military-strategic areas. Thus, the Russian economic cooperation in the oil and energy trade with the countries of East Asia and the Far Eurasian economic integration with the countries of Central Asia form a positive economic «climate» between the regions, as well as provide stability and prospects of cooperation. However cooperation and interaction generates not only incentives for the development, but also evoke some problems and challenges, which will be mentioned in this article.

The distribution in the geological section of two groups of sedimentary rocks, siliceous and carbonate rocks of different composition — has been examined. Acid-base conditions of external geospheres have been reconstructed in consideration of the peculiar conditions of the formation of rocks of different material composition. The acidic environments have been shown to be such conditions in the Archean period, the alkaline environments — in the Proterozoic, and slightly alkaline — in the Phanerozoic. At the same time, in the Archean the weathering was purely chemical, prebiogenic, which determined the intense removal of iron and silica from the basic igneous rocks that covered the surface of the early Earth. The emergence of cyanobacterial photosynthesizing communities, utilization of carbon dioxide led to the change to alkaline environment, which determined the accumulation of magnesites and dolomites. The diverse biota of the Phanerozoic caused the formation of pH values close to modern. The mechanisms and forms of the deposition of carbonate and siliceous materials changed alongside with the evolution of life.

We present our recent experimental results on the pulsed regimes of Raman conversion of highly multimode laser diode (LD) pump radiation into the 1st and higher order Stokes radiation in multimode graded-index fibers. Three different linear cavities of Raman fiber laser with the modulation of losses (by acousto-optic modulator, AOM) or gain (by LD current) are explored and compared. An LD with wavelength of 976 nm is used for pumping enabling Raman lasing at wavelength of the 1st (1018 nm) and 2nd (1064 nm) Stokes orders. At ~27.2-kHz repetition rate corresponding to the laser cavity round-trip frequency (i.e., in the mode-locking regime), nanosecond pulses have been observed for both Stokes orders having the highest peak power of ~300 W in the scheme with bulk AOM and the shortest duration of 5–7 ns in the scheme with fiber-pigtailed AOM. At the same time, the beam quality of generated pulses is greatly improved as compared to that for pump diode (M2 > 20) reaching the best value (M2 = 2.05) for the 2nd order Stokes beam in the scheme with the gain modulation and demonstrating also the most stable regime.

Nemertea is a phylum of nonsegmented worms (supraphylum: Spiralia), also known as ribbon worms. The members of this phylum contain various toxins, including peptide toxins. Here, we provide a transcriptomic analysis of peptide toxins in 14 nemertean species, including Cephalothrix cf. simula, which was sequenced in the current study. The summarized data show that the number of toxin transcripts in the studied nemerteans varied from 12 to 82. The most represented groups of toxins were enzymes and ion channel inhibitors, which, in total, reached a proportion of 72% in some species, and the least represented were pore-forming toxins and neurotoxins, the total proportion of which did not exceed 18%. The study revealed that nemerteans possess a much greater variety of toxins than previously thought and showed that these animals are a promising object for the investigation of venom diversity and evolution, and in the search for new peptide toxins.

Purpose. The resonant overvoltage arises in main electrical networks as a result of random coincidence of some parameters of circuit and its mode and it may exist for a relatively long time. Therefore, the traditional means of limitation of short duration commutation surges are not effective in this case. The study determines conditions of appearance and development of non-sinusoidal mode after switching idle autotransformer to the overhead line of extra high voltage. The purpose of the paper is to choice measures for prevention overvoltage, too. Methodology. The study has used the result of extra high voltage line testing, the methods of electric circuit theory and the simulation in the MATLAB & Simulink package. Results. The simulation model of the extra high voltage transmission line for the study of resonant non-sinusoidal overvoltage is developed. The conditions for the appearance of resonant circuits in the real power line are found and harmonic frequency in which overvoltage arises are obtained. The study proposes using the controlled switching device as a measure to prevent resonance surges and determines the appropriate settings. Originality. The expression for calculation of resonant length of extra high voltage line was derived. The special investigation of processes in the resonant circuit of the extra high voltage transmission line for higher harmonic components of voltage is carried out. The program of switching for control apparatus that prevents non-sinusoidal overvoltage has been developed at the first time. Practical value. The using of the proposed settings of controlled switchgear will prevent the occurrence of hazardous resonant surge on higher harmonic components of voltage.

We review our recent experimental results on the cascaded Raman conversion of highly multimode laser diode (LD) pump radiation into the first- and higher-order Stokes radiation in multimode graded-index fibers. A linear cavity composed of fiber Bragg gratings (FBGs) inscribed in the fiber core is formed to provide feedback for the first Stokes order, whereas, for the second order, both a linear cavity consisting of two FBGs and a half-open cavity with one FBG and random distributed feedback (RDFB) via Rayleigh backscattering along the fiber are explored. LDs with different wavelengths (915 and 940 nm) are used for pumping enabling Raman lasing at different wavelengths of the first (950, 954 and 976 nm), second (976, 996 and 1019 nm) and third (1065 nm) Stokes orders. Output power and efficiency, spectral line shapes and widths, beam quality and shapes are compared for different configurations. It is shown that the RDFB cavity provides higher slope efficiency of the second Stokes generation (up to 70% as that for the first Stokes wave) with output power up to ~30 W, limited by the third Stokes generation. The best beam quality parameter of the second Stokes beam is close to the diffraction limit (M2~1.3) in both linear and half-open cavities, whereas the line is narrower (

The possibilities of the use of acoustic energy generators in various industries. We describe the structure and operation of a piston compressor acoustic gas. The generalized formula for the case of absence of radiation and the pipe with a sharp edge at the free end, which allows to establish a connection between the pressure and velocity of the gas in the plenum at the fundamental harmonic

The article presents an analysis of resources that can be used to test users who study the SQL language. Also, the article describes plan and result of the attack on web applications for learning the SQL language. There are some weaknesses of web applications in terms of their ability to verify the correctness of the compilation of SQL queries, which are also describes here. The conclusion deals with is made about the expediency of developing a specialized test system for verifying the correctness of writing SQL-queries.

Nemertea is a phylum of marine worms whose members bear various toxins, including tetrodotoxin (TTX) and its analogues. Despite the more than 30 years of studying TTXs in nemerteans, many questions regarding their functions and the mechanisms ensuring their accumulation and usage remain unclear. In the nemertean Kulikovia alborostrata, we studied TTX and 5,6,11-trideoxyTTX concentrations in body extracts and in released mucus, as well as various aspects of the TTX-positive-cell excretion system and voltage-gated sodium (Nav1) channel subtype 1 mutations contributing to the toxins’ accumulation. For TTX detection, an immunohistological study with an anti-TTX antibody and HPLC-MS/MS were conducted. For Nav1 mutation searching, PCR amplification with specific primers, followed by Sanger sequencing, was used. The investigation revealed that, in response to an external stimulus, subepidermal TTX-positive cells released secretions actively to the body surface. The post-release toxin recovery in these cells was low for TTX and high for 5,6,11-trideoxyTTX in captivity. According to the data obtained, there is low probability of the targeted usage of TTX as a repellent, and targeted 5,6,11-trideoxyTTX secretion by TTX-bearing nemerteans was suggested as a possibility. The Sanger sequencing revealed identical sequences of the P-loop regions of Nav1 domains I–IV in all 17 studied individuals. Mutations comprising amino acid substitutions, probably contributing to nemertean channel resistance to TTX, were shown.

The informative and in the whole interesting and useful book of James Wilson and, in particular, a principal scheme of the standard facial zones are analyzed. The book is shown to reflect only one and not most important carbonate sedimentation environments. The very environment is commonly used as an absolute etalon, reference to which does not demand any additional proves.