Penza State University

The article analyzes the role of youth associations in the formation and development of youth social activity in modern Russia. Based on the generalization of empirical data from Russian sociological studies, the article examines the levels of youth involvement in social activities, motivational factors, and institutional forms of social activity. The article also explores the role of youth associations in the formation and development of youth social activity in modern Russia. It is argued that youth associations are an important institution for socialization, civic education, and the prevention of deviant behavior. The article demonstrates that participation in youth organizations contributes to the development of civic identity, responsibility, and social engagement. The article concludes that youth organizations are a key resource for socialization and civic development.

A detailed analysis of the structure and dynamics of mortality from ischemic heart disease among the population of the Penza Region in 2023-2024 was conducted based on data from the Promed registry. Age and sex characteristics of lethality, territorial distribution of death cases, structure of initial causes, and immediate causes of death and pathological conditions were studied. A decrease in the percentage of deaths from IHD in 2024 (24.86%) with a predominance of deaths in senile age (43.0%) was revealed. Regularities between three categories of causes of death and age groups were established. The results can be used to improve the organization of cardiological care in the region. The relevance of the problem is due to the high rate of mortality from IHD, while fluctuations in regional indicators demonstrate the influence of local factors and the need for territorially-oriented approaches.

The improvement of electrophysical and electrochemical processing technologies is a key task for modern mechanical engineering, especially in the production of high-precision parts of complex shapes, such as turbine blades and molds. One of the promising directions is the use of processing methods with profile electrodes with vertical feed, which provides increased accuracy, process stability and reduced tool wear. However, the issues of dynamic modeling of such a drive, which are critically important for predicting the behavior of the system and optimizing its operation, have not been sufficiently studied. The purpose of this work is to develop a dynamic model of the vertical feed drive of the profiling electrode and analyze its transients to optimize technological parameters. The study presents a detailed kinematic drive scheme. The methodology is based on a strict energy approach to reducing the parameters of the kinematic target to the motor shaft. Based on the obtained equations of motion, a computer model has been developed in the Simulink environment. The results of modeling transients during direct start-up confirmed the stability of the system and the correctness of the selected parameters. The analysis revealed the oscillatory nature of the transient process caused by elastic bonds, and showed a smooth transition to a steady state with a slight overshoot, which is acceptable for high-precision positioning tasks. An effective linear model of an electromechanical actuator is presented, which has proven its adequacy as a basic tool. The analysis showed that in order to further improve the accuracy of the predictive ability of the model, it is necessary to take into account significant nonlinear factors: variable stiffness, kinematic gaps, temperature deformations and gradual wear of nodes.

Sexual reproduction is a hallmark of most eukaryotes, yet hybridization can lead to alternative reproductive strategies, such as hybridogenesis. During hybridogenesis, found in the European water frog (Pelophylax esculentus) complex, one of the parental genomes is eliminated during gametogenesis, and the other one propagates clonally to gametes. We analyzed diploid hybrid males from populations common for hybrids and Pelophylax lessonae (L-E systems) from the eastern part of their distribution range. All but one hybrid produced spermatocytes and spermatids with Pelophylax ridibundus chromosomes, suggesting premeiotic elimination of P. lessonae genome and endoreplication of the P. ridibundus genome. We also observed spermatocytes with 13 or 26 univalents, indicating alterations in genome elimination and endoreplication. By comparing spermatocytes with germ cell genome composition, we suggest that genome elimination and endoreplication do not occur in adult males. Further, we examined introgressions using mitochondrial and nuclear genetic markers and comparative genomic hybridization. Most hybrids carried P. ridibundus and P. lessonae haplogroups, but five had Pelophylax cf. bedriagae mitochondrial DNA. In one hybrid, we revealed introgression of P. ridibundus chromosomal segments on P. lessonae chromosome. Although L-E systems are generally considered as stable, our results indicate variability in hybrid male gametogenesis, which may be related to introgressive hybridization.

Background. The relevance of the problem of developing new methods for efficient control of THz radiation characteristics is dictated by the needs of the development of THz technology. For practical purposes, the ability to control the polarization and intensity of THz radiation in nanostructured media and change their magneto-optical properties under the influence of an external magnetic field is important. However, in the THz range there are no materials that have the ability to influence the state of radiation polarization in a non-reciprocal manner. The magneto-optical activity of nanosystems with combined magnetic and plasmonic functions can be significantly increased by enhancing the electromagnetic field associated with plasmon resonance, and magnetic functionality allows controlling plasmonic properties using an external magnetic field. Excitation of surface magnetoplasmons-polaritons in graphene and graphene structures dramatically changes the magneto-optical response, and this makes graphene a unique platform for magneto-optical phenomena controlled by surface magnetoplasmons-polaritons. Aim. The purpose of this work is to develop new methods for efficient control of THz radiation characteristics and numerical study of the influence of gyrotropy and excitation of surface magnetoplasmons-polaritons on the parameters (polarization) of the scattering field on magnetoplasmonic graphene gratings in the THz frequency range. Methods. This important scientific problem related to modeling the scattering of THz waves on magnetoplasmonic graphene gratings and investigation of the characteristics of the scattered THz radiation can be solved by automated modeling tools using the CST MWS software package based on the solution (by the finite element method in the frequency domain) of the electrodynamic diffraction problem. Results. Magnetoplasmonic gratings of graphene nanoribbons in a perpendicular external magnetic field were selected as the object of analysis, their models were developed in the CST MWS software package, and the possibility of resonant frequency tuning was shown. The results of modeling 3D e-Field scattering patterns of normally and at an angle of 30° incident plane wave of p- or s-polarization on the cell of the magnetoplasmonic graphene nanoribbone grating, as well as the calculation of the ratio of the amplitudes of the horizontal and vertical components Ex/Ey of the scattered field and the axial ratio AR at the cross-section points (φ = 0°) of the main lobe of 3D e-Field scattering patterns at resonant frequencies are obtained. Methods of magnetic control of the polarization of scattered THz radiation based on the selection of operating frequencies corresponding to the magnetoplasmons-polaritons resonances are revealed, and the possibility of transforming the linear polarization of the incident wave, depending on the magnitude of the external magnetic field, is shown, while the transmitted wave can have elliptical polarization (the polarization ellipse is elongated), the reflected wave can have elliptical polarization close to circular. Conclusion. The possibility of magnetic control of the polarization of scattered THz radiation on magnetoplasmonic graphene gratings makes it possible to create integrated photonic devices for telecommunications, THz communications and visualization, biomedical technologies, sensors, including biosensors, and optoelectronics.

The aim of the study is to identify mechanisms through which students’ emotional well-being influences their academic motivation within a multinational university context. The article explores sociocultural factors related to ethnicity, traditions, and the dynamics of intercultural interaction. Findings demonstrate that internal cognitive motives reinforce the personal dimension of well-being, while pressure from ethnocultural norms increases maladaptive strategies – such as avoidance and external prestige motives – which lead to emotional distress. Scientific novelty lies in the integrative approach that combines models of emotional well-being and academic motivation with cross-cultural and metacognitive analysis, allowing the identification of moderation mechanisms specific to multinational settings. Results show that a high level of emotional well-being, grounded in a sense of competence and autonomy, is a key predictor of intrinsic academic motivation; whereas sociocultural directivity shifts the motivational balance toward external regulation. The conclusions highlight the need to promote interethnic tolerance, metacognitive self-regulation, and inclusive educational practices to build sustainable student motivation.

в статье рассматриваются средства повышения уровня мотивации и заинтересованности учеников в изучении английского языка в дистанционном форме. Рассматриваются такие средства, как геймификация учебного процесса, интерактивные задания и система вознаграждения.

The quantitative determination of the amount of chlorophylls in the grass ofthe Agastache rugosa by spectrophotometrywas carried out. Optimal pigment extraction conditions have been developed to maximize the yield of the target compounds.It has been shown that effective extraction is achieved using 95% ethyl alcohol (raw material:extractant ratio 1:30), a grinding degreeof 1 mm and an extraction timeof 90 minutes. Chlorophyll a has been identified as the dominant pigment (analytical wavelength 664±2 nm). The maximum amountof chlorophylls in the grass of the wrinkled mulberry was 9.30%, which indicates the prospectsof this plant asa source of valuable pigments.

Background. Transformation of the morphology of the post-infarction myocardium changes the electrical characteristics of the heart muscle, increasing the risk of life-threatening arrhythmias. Objective . The aim of the study was to compare the structural and electrical features of the heart muscle in post-infarction patients. Design and methods. The study participants were 105 (85.4 %) patients who had suffered an MI, aged 56.7±8.4 years. Six months after the MI, the patients underwent cardiac magnetic resonance imaging (MRI) (GE SIGNA Voyager tomograph, GE HealthCare, USA) with the introduction of a contrast agent — gadoteric acid. Six and 12 months after the MI, the patients underwent multi-day electrocardiogram monitoring (MMEKG) for 72 hours. Results. According to MMEKG, unstable paroxysms of VT were registered in 9 (6.8 %) patients. Frequent (>30/h) ventricular extrasystoles (VE) were correlated with the percentage of scar zone — r=0.679 (p=0.0101), the mass of the heterogeneous zone — r=0.721 (p=0.00951). An association was established between polymorphic VE with the presence of areas of microvascular obstruction r=0.812 (p=0.0095) and intramyocardial hemorrhage r=0.798 (p=0.0114). Most parameters of autonomic regulation and heart rate turbulence showed a moderate negative relationship with the scar mass. According to the data of univariate regression analysis, risk markers of unstable VT were established: scar zone mass, end-diastolic size, turbulence slope, SDNN variability parameter. Conclusion. Predictors of unstable runs of ventricular tachycardias within 12 months after myocardial infarction are the mass of the scar zone, the values of the left ventricular end-diastolic diameter, the values of the turbulence slope and the SDNN variability parameter.