托木斯克国立大学

Early Devonian magmatism in the Minusinsk trough of the Altai-Sayan Large Igneous province provides a critical record of regional geologic history. In this study, we determined the U-Pb baddeleyite isotope age, major and trace element geochemistry, and Sr-Nd isotope composition of igneous rocks in the Uryup sector of Minusinsk trough, with the aim of constraining their magmatic origin. The volcanic succession is divided, from base to top, into three Suites: (1) the Bazyr Suite, composed of basalts, trachybasalts, basaltic trachyandesites, transitional tephrites-trachybasalts, and phonotephrites; (2) the Beresh Suite, consisting of trachybasalts, basaltic trachyandesites, phonotephrites, tephriphonolites, and feldspathoid ijolites; and (3) the Ashpan Suite, comprising basalts, trachybasalts, and basaltic trachyandesites. The Early Devonian age of these Suites, established in previous geological and palaeontological studies, is confirmed here by new U-Pb geochronological data on baddeleyite obtained by ID-TIMS. Rare-element concentrations in all mafic rocks, regardless of alkalinity, vary widely, showing features typical of both oceanic island basalts and island arc basalts. Compared with sub-alkalic counterparts, alkalic mafic rocks contain abundant nepheline phenocrysts (up to 30 wt.%) and are enriched in Na2O, Al2O3, Rb, Ba, Th, U, K, Nb, REE, and radiogenic Sr, while exhibiting similar and only slightly variable radiogenic Nd values. We propose a model in which all Uryup sector rocks were derived from a single sub-alkalic basaltic parental melt generated in the asthenospheric mantle by the influence of a mantle plume on fragments of ancient supra-subduction lithospheric mantle. Geochemical and isotopic variations are inconsistent with a simple comagmatic relationship between sub-alkalic and alkalic rocks or with fractional crystallization as the sole controlling process. Bazyr sub-alkalic basaltic magmas experienced simultaneous fractional crystallization and contamination by silicate crust. Beresh phonotephrites, tephriphonolites, and feldspathoid ijolites formed from differentiated sub-alkalic melts through carbonate contamination, possibly within the continental crust.

This article provides the first comprehensive description and assessment of environmental changes in a unique natural transboundary region-South-Eastern Altai, which is located in the arid territories of Russia and Mongolia. This region of Asia is rightfully included in the high-mountain Third Pole (Roof of the World). In three key areas, Tsambagarav Massif (Mongolia), Mongun-Taiga Massif, and North-Chuya Ridge (Russia), the following are considered: (1) the latest dynamics of glaciers from the early 1960s (beginning of regular instrumental observations) to the present day; (2) climate change and land use systems; and (3) the characteristics of the biota and the causes of its dynamics. The article concludes with a consideration of (4) population adaptation models.

Samples of hydroxyapatite modified with strontium ions were synthesized. The amount of doped ions during the synthesis varied from 0.1 to 0.5 mol. The phases were identified and their crystallographic parameters were determined using X-ray phase and X-ray structural analysis. It was found that there is an isomorphic substitution of calcium ions by strontium ions in the samples of strontium- modified hydroxyapatite. The surface of the samples was studied using scanning electron microscopy and X-ray spectral microanalysis and an assessment was made of the quantitative distribution of chemical elements on the surface: strontium is uniformly distributed over the surface of the synthesized samples. An assessment of the antibacterial properties in relation to Escherichia coli and Staphylococcus aureus bacteria was carried out. All samples have bactericidal properties.

Introduction. The challenges associated with the digital transformation of the university en-vironment are becoming increasingly significant in the current context of the growing prevalence of distance and hybrid learning formats. Aim. The present study aims to analyse students' digital commu-nication in both formal and informal educational contexts, as well as to identify its thematic and emo-tional structures based on digital footprints. Methodology and research methods. The research is grounded in systemic and socio-communicative approaches, which enable communication to be understood as a multi-layered socio-pedagogical system. The empirical data comprise over four million messages and comments collected from university online environments, analysed using automated topic and senti-ment analysis tools. Methods from digital linguistics, statistical validation, and case study analysis of university communities were employed. Results and scientific novelty. For the first time, this study identi-fies stable types of digital interaction based on an extensive collection of digital footprints from students at Russian universities. These footprints reflect emotional fluctuations, responses to external events, and characteristics of self-organisation within the networked educational environment. A conceptual model is presented that systematises the levels of university communication-formal, informal, networked, and analytical-as a methodological tool for analysing digital communication. Practical significance. The re-search findings can be applied to the management of university educational environments, the analysis of academic motivation and students' emotional states, and the design of monitoring programmes and support systems for students' digital well-being.

The genus Ptilodontella Kiriakoff, 1967 (the type species Bombyx cucullina Denis & Schiffermüller, 1775) has been separated from the synonymy with the genus Ptilodon Hübner, 1822 (the type species Phalaena camelina Linnaeus, 1758) and reinstated as a distinct genus (stat. rev.) based on differences in male and female genitalia. Additionally, a new species, Ptilodontella albertisp. n., has been described from the Greater and Lesser Caucasus and the Pontic Mountains spanning northern Turkey, with the type locality in the Republic of South Ossetia. This new species differs from its close relatives Ptilodontella cucullina (Denis & Schiffermüller, 1775) comb. rev. and Ptilodontella saerdabensis (Daniel, 1938) comb. n. in the shape of antennal rami and the genitalia of both sexes. Variability in wing patterns among species is demonstrated and is regarded as an unreliable feature for distinguishing the three species. The distribution boundary between the new species and P. cucullina lies between the lowland Pontic steppe and the foothills of the Greater Caucasus, while the boundary between the new species and P. saerdabensis is situated between the Lesser Caucasus and the Alborz Mountains. None of these species are found to fly sympatrically.