Investigation of Changing Volt-Ampere Characteristics of AlGaInP Heterostructures with Multiple Quantum Wells under Ionizing Radiation

The results of research into degradation of volt-ampere characteristics of light emitting diodes produced on the base of AlGaInP heterostructures with multiple quantum wells are presented on the example of light emitting diodes (emission wavelengths 623 nm and 590 nm) under gamma quantum and fast neutron radiation in passive powering mode. The shifts of volt-ampere characteristics into the higher voltage range have been observed in conditions of increasing neutron fluence and radiation dose. The observed increase in the resistance of ohmic contacts is caused by the rising resistance of adjacent area, which in its turn results from the changing mobility of charge carriers. The latter varies with the growth of introduced defects under irradiation. Two different areas of current generation have been identified. A mechanism of current generation depends on injected charge carriers in the range of mid-level electron injection. Moreover, the range of high electron injection is distinguished by changing resistance of light emitting diode cores alongside with current generation conditioned by charge carrier injection

Conceptualization of user activities in the social network in the conditions of distance education

No artigo, as mídias sociais são analisadas através do foco de entender este último como um espaço virtual da mídia, o que reflete indicadores identificados dos usuários como: interesse, desejo, entusiasmo e direção dos processos de integração. A relevância do estudo é determinada pelo desenvolvimento insuficiente e inconsistência dos conceitos e resultados empíricos da pesquisa sobre os processos de diferenciação da comunidade das redes sociais e seu papel nas condições da educação a distância. Foram utilizados os métodos filosóficos, de análise e hermenêutica: interpretação, conceituação, análise comparativa. Como base teórica e metodológica, utilizamos o aparato categórico da filosofia social, matemática, teoria da prática, pragmatismo, epistemologia social. Utilizamos abordagens para extrair a atividade de grupos de usuários em uma rede social de várias camadas: 1) extrair grupos em cada camada separadamente e, em seguida, combinar comunidades em todas as camadas; 2) primeiro transformar a rede social em uma camada e, em seguida, procurar diferentes grupos dentro

Clinical and laboratory indicators in pregnant women with preeclampsia

The objective of this study is to compare clinical and laboratory indicators in pregnant women with preeclampsia (PE) compared with women with physiological pregnancy. The study group included 209 women with physiological pregnancy and 250 pregnant women with PE. We studied coagulogram data, biochemical blood analysis, and the level of systolic and diastolic blood pressure before and during pregnanc

Online Education after the Pandemic: Student Problems and Opportunities Research Using Big Data Tools

This paper presents a scientifically based approach to analyzing large volumes of data from digital traces of students on social networks, which allows you to effectively identify emerging and most discussed problems among students, as well as highlight pain points that provide opportunities for growth, development of universities and improvement of the characteristics of the educational process, support for students etc. The study is based on a thematic analysis of messages published in university communities on the VKontakte social network using big data tools. The study results showed that Russian university students still face a number of challenges, including weak technical infrastructure at universities, a digital divide in access to online education, and negative attitudes towards distance learning.The scientific problem of the study is the contradiction between the existing volume of unstructured data of students’ digital traces in social networks and the lack of a scientifically-based and proven methodological approach to the analysis and evaluation of this voluminous data, which creates obstacles to fundamental research into the relationship between students’ activity in social networks and their satisfaction quality of the educational process. The practical focus is determined in conducting data analysis using big data tools. The findings and evidence-based implications are useful for developing innovative strategies and tools for assessing and supporting students.The results show that the use of big data tools for tracking trends based on digital traces of students on social networks provides highly accurate analytical data and can become the basis for identifying problematic situations in individual universities and the industry as a whole, for data-driven decision-making and management

LEDs based upon AlGaInP heterostructures with multiple quantum wells: comparison of fast neutrons and gammaquanta irradiation

The paper presents the research results of watt and volt characteristics of LEDs based upon AlGaInP heterostructures with multiple quantum wells in the active region. The research is completed for LEDs (emission wavelengths 624 nm and 590 nm) under irradiation by fast neutron and gamma-quanta in passive powering mode. Watt-voltage characteristics in the average and high electron injection areas are described as a power function of the operating voltage. It has been revealed that the LEDs transition from average electron injection area to high electron injection area occurs by overcoming the transition area. It disappears as it get closer to the limit result of the irradiation LEDs that is low electron injection mode in the entire supply voltage range. It has been established that the gamma radiation facilitates initial defects restructuring only 42% compared to 100% when irradiation is performed by fast neutrons. Ratio between measured on the boundary between low and average electron injection areas current value and the contribution magnitude of the first stage LEDs emissive power reducing is established. It is allows to predict LEDs resistance to irradiation by fast neutrons and gamma rays

Dynamics of Students’ Opinions in the Context of the Transition to Online Learning Based on Social Network Data

The article presents the results of the analysis of users’ sentiment in social networks, performed using big data tools. The research was aimed at developing the methodology, which enables to analyze the content of social networks, assess students’ attitude to the transition to online learning in conditions of COVID-19 pandemic, identify dynamics and main trends in student satisfaction with the quality of educational process. We explored about 2 million posts and comments posted in university social networks (more than 1000 university public pages) for the period from Sept 2020 to July 2021. Special attention was paid to the problems of communication between students and teachers, strategies to solve them, an emotional reaction. PolyAnalyst software was applied for data precleaning. It has been found that the main problem affecting the quality of education is a change in the mechanisms of interaction between students and teachers. Based on student publications in social networks, we have identified the strategies for adapting students to online learning. We came to a conclusion that teachers’ support of students is crucial in preventing and solving social and academic problems in conditions of online learning. One of the ways to improve interaction between students and teachers, raise students’ involvement is using discussion forums, chats in messengers for academic purposes, and providing teachers’ methodical support

Digital footprint in predicting school graduates’ educational strategy

This research article aims at evaluating the results of the school graduates’ educational strategy transformation with the help of digital footprint data. The analysis of official and unofficial Internet communities of universities in the social network «VKontakte» shows that their active users are school graduates, who thus receive the necessary information about the university. The method presented can become a promising tool to forecast the demand for higher education. The study covers the period from 2019 to 2021, a total of 502 thousand user profiles having been identified, 246 thousand accounts included in the final sample. The results show that during the analyzed period the number of user subscriptions to university communities has decreased in all Russian regions. The orientation towards universities located in other regions has also changed: these were more popular before the pandemic, being subscribed to by the majority of students, whereas after the spread of COVID-19, most of the graduates began to choose universities located in their native region. A significant limitation of this method is that a number of profiles are closed, which logically does not allow to use them in further analysis. The results of the study show, however, high validity and wide opportunities for the use of the digital footprint method when predicting young people’s educational trajectory and planning the enrollment campaign, both on the scale of the university and the whole country.В исследовательской статье с использованием данных цифровых следов оцениваются результаты трансформации образовательной стратегии учащихся 11-х классов средней школы. Анализ официальных и неофициальных вузовских интернет-сообществ в социальной сети «ВКонтакте» показал, что их активными пользователями являются выпускники школ, которые таким образом получают необходимую информацию о высшем учебном заведении. Представленный в статье метод использования цифровых следов может стать перспективным инструментом прогнозирования спроса на высшее образование. Проведенное исследование охватило период с 2019 года по 2021 год, всего было идентифицировано 502 тысячи профилей пользователей, в финальную выборку попали 246 тысяч аккаунтов. Результаты показали, что за анализируемый период произошло сокращение числа подписок пользователей на вузовские сообщества. Данный процесс наблюдался во всех российских регионах. Также изменилась ориентация на вузы, расположенные в других регионах. Если до пандемии большинство учащихся подписывалось на сообщества вузов, находящихся в другом регионе, то после нее большая часть выпускников стала выбирать вузы родного региона. Существенным ограничением метода использования цифровых следов является то, что ряд профилей относится к закрытым, и это не позволяет использовать их в дальнейшем анализе. Тем не менее результаты исследования показали высокую валидность и широкие возможности использования метода цифровых следов в предсказании образовательной траектории молодежи и планировании приемной кампании в масштабах как вуза, так и страны в целом

Integrative Neuropsychological Characteristics of Subcortical-Frontal Brain Regions as a Schizophrenia Liability Factor

Para estudiar las características de las regiones cerebrales subcórtico-frontal, se investigaron la función y la evaluación de su relación con la vulnerabilidad a la esquizofrenia en 59 pacientes y 23 controles, empleando los métodos neuropsicológicos de Luria. El análisis estableció anormalidades bilaterales de la función de las zonas lobulares prefrontal y frontal profunda en pacientes comparados con los controles. Estas anormalidades eran más predominantes en el hemisferio izquierdo. Las coeficientes de correlación punto-biserial de algunos indicadores neuropsicológicos integrativos con la vulnerabilidad a la esquizofrenia eran de 0,39 ± 0,11 y 0,28 ± 0,09, respectivamente. Los datos obtenidos llevan a la discusión de los indicadores neuropsicológicos integrativos de regiones subcortical-frontales del cerebro que se revelan como marcadores potenciales de vulnerabilidad a la esquizofrenia y confirma el papel de la asimetría estructural y funcional del cerebro en la patogénesis de la esquizofrenia.In order to study neuropsychological characteristics of subcortical-frontal brain regions function and assessment of their relation with vulnerability to schizophrenia 59 patients and 23 controls were investigated using Luria’s neuropsychological methods. The analysis established bilateral abnormalities of the function of prefrontal and profound frontal lobe zones in patients as compared with controls. These abnormalities were more predominate in the left hemisphere. Point biserial correlation coefficients of determined integrative neuropsychological indicators with liability to schizophrenia were 0.39 ± 0.11 and 0.28 ± 0.09, for the left and right brain zones respectively. The obtained data permits discussion of the integrative neuropsychological indicators of subcorticalfrontal brain regions as potential markers of liability to schizophrenia and confirms the role of structural and functional brain asymmetry in the pathogenesis of schizophrenia