Promene trofičkog stanja u reci Dnjepar i njihov uticaj na zajednicu riba

Ispitivane su promene structure zajednica fitoplanktona i riba, kao i koncentracije azota i fosfora u međugraničnoj reci Dnjepar. Konstatovano je da je koncentracija mineralnog azota najvažniji factor akumulacije antropogenog zagađenja nizvodno u ispitivanim delovima reke Dnjepar. Ukupna količina riba se povecala nizvodno sa povećanjem trofičkog statusa reke. U isto vreme prosečna individualne težina se nizvodno smanjivala

Organization of virtual interaction in the context of the coronavirus pandemic

The organization of the educational process should be carried out taking into account the epidemiological situation and following the requirements that are due to quarantine measures. The leadership of vocational schools is looking for ways to conduct classes in a safe environment, assessing the potential risks for teachers and students. Higher schools implement the possibilities of electronic technologies as a factor in ensuring the safety of subjects of the educational process for communication between students and teachers at a distance. The purpose of the article is to review the experience of organizing virtual interaction between students and teachers within the framework of e-learning during the spread of coronavirus infection. The article reveals the possibilities of electronic technologies that allow communicating at a remote distance. The preparation of students in critical conditions is carried out using various electronic means that promote active interaction. The results of the study reflect the opinion of students of higher educational institutions about the use of virtual interaction tools. The results obtained using the Likert scale allow us to say that the majority of the respondents are active participants in virtual interaction and are ready to continue to communicate using the presented means despite the existing difficulties

Tunable Bose-Einstein condensation and roton-like excitation spectra with dipolar exciton-polaritons in crossed fields

We develop the many-body theory of dipolar exciton-polaritons in an optical microcavity in crossed transverse electric and in-plane magnetic fields. Even for relatively weak fields, we reveal the existence of two minima in the bare lower-polariton dispersion, which give rise to the tuneable transition between the polariton Bose-Einstein condensate and that of excitons, produced by the competition between these minima. We predict that such dipolar condensate exhibits a roton-maxon character of the excitation spectrum, never before observed for polaritons. We show that upon the transition between the two condensation regimes, the weak correlations in the polariton gas give way to the intermediate interparticle correlations characteristic for excitons, and that the transition is accompanied by a sharp quenching of photoluminescence as the lifetime is increased by several orders of magnitude. While in the polariton regime, the luminescence peak corresponding to the condensate is shifted to a non-zero angle. The angular dependence of the two-photon decay time in the Hanbury Brown and Twiss experiment is calculated and used as a tool to evidence the formation of the macroscopically-coherent state. Our proposal opens opportunities towards manipulating the superfluid properties and extended-range dipole-dipole correlations of exciton-polariton condensates.Comment: 16 pages, 6 figure

Fauna composition and diurnal dynamics of bloodsucking mosquitos abundance of Dnipropetrovsk region

Наведено дані про видовий склад кровосисних комарів Дніпропетровської області та встановлено домінантні види. Досліджено добову динаміку чисельності кровосисних комарів, виділено чотири періоди добової активності для району дослідження. Проведено порівняльний аналіз фауни родини Culicidae трьох агрокліматичних районів. Отриманий матеріал може бути використаний для ефективного проведення заходів з обмеження чисельності кровосисних комарів на території області. Приведены данные о видовом составе кровососущих комаров Днепропетровской области и установлены доминирующие виды. Изучена суточная динамика численности кровососущих комаров района исследования, выделены четыре периода суточной активности. Проведен сравнительный анализ фауны семейства Culicidae трех агроклиматических районов. Полученный материал может быть использован для эффективного проведения мероприятий по ограничению численности кровососущих комаров на территории области.Species composition of mosquitoes in Dnipropetrovs’k region is presented and dominating species are established. Diurnal dynamics of bloodsucking mosquitos’ number was studied. Four periods of daily activity were marked out. Comparative analysis of Culicidae fauna in three agricultural climatic areas was made. Data obtained may be used for effective measures of the mosquitos’ limitation in the region

Quantitative and qualitative analysis of sunflower pollen (<i>Helianthus</i> L.) and it’s use in breeding work

Background. In breeding work, it is necessary to take into account such an important feature as male sterility of the hybrids obtained. If a plant has visually visible anthers and pollen, the quality of the pollen grains themselves may be low. It is necessary to carry out not only a visual analysis, but also a cytological study of pollen in order to properly assess the reproductive potential of plants.Materials and methods. Wild species, some cultivars, lines and hybrids of sunflower from the collection of the N. I. Vavilov All-Russian Institute of Plant Genetic Resources were taken as objects of research. The plants were grown on the fields of Kuban Experiment Station. Pollen was collected from preinsulated inflorescences, fixed in FAA solution and stained with acetocarmine. The ratio of fertile pollen grains to the total number of pollen grains (in %) was calculated, the diameter of the pollen grains was measured, and variability curves were drawn.Results. Mature pollen grains in sunflower are rounded, tricolpate-poral, threecelled; the average pollen diameter in cultivated sunflower is 28–32 μm; in wild species, the range is from 20– 22 μm to 32–34 μm. All accessions were divided into three groups. Fertile: high level of fertility (75–99%) and low morphological heterogeneity of pollen; the variation curve for the average diameter was characterized by one distinct peak. Most of the studied accessions were included here: cultivars, most of the lines and some of the wild species. Semi-fertile: the number of well-stained pollen grains is below 75%; there are differences in the degree of staining and size of the pollen; the variation curve had additional peaks. This group included some of the lines, hybrids and wild species. The greatest morphological heterogeneity was observed in the group of perennial interspecific hybrids. Sterile: pollen grains were absent or were observed very sporadically.Conclusion. To assess the fertility of plants, it is important not only to determine the degree of staining in pollen grains, but also to rank them by diameter and construct variation curves to reveal morphological heterogeneity of pollen

Determination of Total Antioxidant Content in Various Drinks by Amperometry

In the present work the total content of phenolic antioxidants in juice of some fruit and vegetables, in wines, water extracts of tea and herb were measured by amperometry. Efficiency of the method allowed determining the total antioxidant content in their binary and multimixes, including processes of frosting-defrosting and juice diluting as well. The deviation of experimentally received values of the total antioxidant content in some drink mixes from the values calculated proceeding from the additivity principle of the antioxidant content in separate drinks has been revealed

Interdisciplinary Studies of Jet Systems using Euler Methodology and Computational Fluid Dynamics Technologies

This study aims to conduct interdisciplinary research using computerized solutions to inventive problems in fluidics. The chosen direction of work relates to the scientific search for new opportunities for extremal control of the thrust vector within a complete geometric sphere (with the range of rotation angle change for the thrust vector being ±180° in any direction). This study assesses the prospects for the emergence of patentable innovative solutions for maneuverable unmanned vehicles. One of the most urgent tasks is to increase the process efficiency in forming fluid medium flow, expanding opportunities for controlling this flow parameter. The research uses an interdisciplinary approach with simulation modeling. The authors of the paper reveal new possibilities for using an ejector with two curved mixing chambers to create special jet units. Calculations (CFD) have confirmed the performance of the simulator ejector when controlling the thrust vector with 90° and 180° rotation. Manufacturing physical micromodels used additive technologies to allow simulation modeling under laboratory conditions. Using “data mining” methods, it was shown for the first time that, based on Euler’s ideas and methodology, it is possible to create a new methodology for teaching and solving inventive problems. The research results apply to power engineering and unmanned vehicles. Some results of scientific studies can be used to create special computer programs working together with artificial intelligence to create advanced techniques and technologies. Doi: 10.28991/HIJ-2023-04-04-01 Full Text: PD

Развитие макропруденциального регулирования банковского кредитования физических лиц в России

The article highlights the use of macroprudential instruments by the Bank of Russia that regulate the population Lending of the Russian banking sector. The purpose of the work is to study the theoretical background and practical results of using indicators of the total cost of credit and the debt load of the population to ensure stability of the banking sector. The authors used methods of qualitative and quantitative analysis of scientific publications, regulatory sources, retrospective statistics. The study showed that initially, the regulator introduces new macroprudential instruments as recommended, and subsequently transfers them to mandatory. The regulatory mechanism is based on the ratio dependence of the bank capital adequacy on the actual values of the total loan cost and debt load of the borrower - individual. The mortgage debt to collateral value ratio supports the housing mortgage lending regulation process. The authors concluded that the banking sector’s reaction to the introduction of the total credit cost indicator is more prominent than the introduction of the debt burden indicator. When the Bank of Russia obliged to take into account the full cost of the loan when measuring capital adequacy, banks were not able to increase capital; they reduced high-risk lending. The practice of macroprudential regulation of credit risks in the banking sector is complemented by the introduction of credit holidays for borrowers - individuals, who are struggling because of the pandemic. The obtained theoretical and practical results can be used in the development of the financial stability regulation practice in Russia, at the micro-level - when designing and changing credit policy.Статья посвящена применению Банком России макропруденциальных инструментов, регулирующих кредитные операции российского банковского сектора с населением. Цель работы - исследовать теоретические предпосылки и практические результаты использования показателей полной стоимости кредита и долговой нагрузки населения для обеспечения стабильности банковского сектора. Использованы методы качественного и количественного анализа научных публикаций, нормативно-правовых источников, ретроспективных статистических данных. Исследование показало, что новые макропруденциальные инструменты регулятор первоначально вводит как рекомендуемые, а в дальнейшем переводит в обязательные. Механизм регулирования основан на зависимости показателей достаточности банковского капитала от фактических значений показателей полной стоимости кредита и долговой нагрузки заемщика - физического лица. Регулирование ипотечного жилищного кредитования дополнено использованием показателя, характеризующего соотношение между ипотечным долгом и стоимостью обеспечения. Сделан вывод, что реакция банковского сектора на введение показателя полной стоимости кредита более выраженная, чем на введение показателя долговой нагрузки. С введением механизма определения достаточности банковского капитала в зависимости от показателя полной стоимости кредита физическому лицу в условиях ограниченных возможностей банков увеличивать собственные средства пропорционально растущей величине рисков банки сократили выдачи высокорискованных кредитов. На фоне пандемии коронавируса практику макропруденциального регулирования кредитного риска банковского сектора дополняет административное введение кредитных каникул в связи с возможным снижением доходов заемщиков - физических лиц. Полученные теоретические и практические результаты могут быть использованы при развитии практики регулирования финансовой стабильности российского банковского сектора, на микроуровне - при формировании и корректировке кредитной политики