12 research outputs found
ИССЛЕДОВАНИЕ ДИНАМИКИ СЕЛЕЙ НА ЭКСПЕРИМЕНТАЛЬНОМ СТЕНДЕ
Designed and manufactured a test stand for the dynamic characteristics of debris-flows and for physical modelling of debris-flows. The stand is a rectangular cross-section tray with a length of 3.0 m, a width of 0.25 m, a depth of 0.25 m. The slopes of the tray vary from 10o to 45o. Rods are installed in the tray to accommodate load cells for measuring pressure, speed and temperature. The process of moving the debris-flow through the transparent wall of the debris-flow tray is filmed by a high-speed video camera. During the experiment, the velocity and high- velocity pressure of water flow and artificial debris-flow were measured. The tray was installed with a slope of 12o. Water flow was started up on the tray (to measure the flow rate and the value of the velocity head, which were then used as reference values). Then the tray was put into the flow of the prepared debris-flow mixture. The debris-flow mixture was prepared from a dredged-crushed proluvial-deluvial deposits of Holocene age with a loamy aggregate with a density of 2210 kg/m3. The density of the prepared debris-flow mixture was 1756 kg/m3. Dynamic viscosity of the debris-flow mass measured by the Stokes method was 0.0498 Poise, kinematic viscosity of the debris-flow mass was 0.0928 Stokes. Data on the debris-flow velocity measured directly during its movement of the debris-flow is not enough. Therefore, methods for calculating the speed of a debris-flow slide in its are important. One of these methods is the method of calculating the debris-flow velocity by the magnitude of the speed head (on the traces of the debris-flow on the trunks of trees). That method is based on the formula of E. Torricelli. The results of the experiment showed that the measured debris-flow velocity, calculated from the magnitude of the velocity head, was lower than the measured velocity before the obstacle and higher than the measured velocity after the obstacle. The measured velocity of the debris-flow passage of the entire tray was close to the calculated one.Разработан и изготовлен стенд для исследования динамических характеристик селей и физического моделирования селей. Стенд представляет собой прямоугольный в поперечном сечении лоток длиной 3,0 м, шириной 0,25 м, глубиной 0,25 м. Уклоны лотка изменяются от 10о до 45о. Выше лотка устанавливается ёмкость, заполняемая водой или приготовленной селевой смесью. Для наблюдения за внутренней структурой селевого потока обе стенки селевого лотка выполнены прозрачными. В лотке могут быть установлены металлические штанги для размещения тензодатчиков для измерения давления, скорости и температуры. Процесс движения селя через прозрачную стенку селевого лотка снимается скоростной видеокамерой. В ноябре 2019 г. был проведён эксперимент по измерению скорости селя. Измерялись скорость и скоростной напор водного потока и искусственного грязекаменного селя. Лоток был установлен с уклоном 12о. По лотку был пущен водный поток (для измерения скорости потока и величины скоростного напора, которые затем использовались как эталонные значения). Затем по лотку был пущен поток из подготовленной селевой смеси. Селевая смесь была приготовлена из дресвяно-щебенистого элювиально-делювиального грунта возрастом QIV с суглинистым заполнителем (лёгкий и средний суглинок, до 30%) плотностью в естественном залегании 2210 кг/м3. Плотность суглинка – 1910 кг/м3. Дресва и щебень представлены алевролитом средней прочности плотностью 2210 кг/м3. Измеренная по методу Стокса динамическая вязкость селевой массы составила 0,0498 Пуаз. Рассчитанная кинематическая вязкость селевой массы составила 0,0928 Стокс. Поскольку данных о скорости селей, измеренных непосредственно во время его движения, недостаточно, особую важность приобретают методы расчёта скорости селя по его следам, определённые при полевых исследованиях после схода селя. Одной из таких методик является методика определения скорости селя по величине скоростного напора: по следам селя (обмазкам) на стволах деревьев и т.д. Эта методика основана на формуле Э. Торричелли. Результаты эксперимента показали: скорость грязекаменного селя, рассчитанная по величине скоростного напора, оказалась ниже измеренной скорости до препятствия и выше измеренной скорости после препятствия. Измеренная скорость прохождения селем всего лотка оказалась близка к рассчитанной.
Литература
Виноградов Ю.Б. Искусственное воспроизведение селевых потоков на экспериментальном полигоне в бассейне р. Чемолган // Селевые потоки: сборник. М.: Гидрометеоиздат, 1976. С. 3-7.
Виноградов Ю.Б. Этюды о селевых потоках. Л.: Гидрометеоиздат, 1980. 144 с.
Казаков Н.А., Генсиоровский Ю.В., Боброва Д.А., Окопный В.И., Казакова Е.Н., Рыбальченко С.В. Условия формирования связных селей при слабых осадках и распределение динамических характеристик в селевом потоке // Геориск. 2015. № 4. С. 12-16.
Степанов Б.С., Степанова Т.С. Механика селей: эксперимент, теория, методы расчета. М.: Гидрометеоиздат, 1991. 379 с.
Vinogradova T.A., Vinogradov A.Yu. The experimental debris flows in the Chemolgan river basin. Natural Hazards. 2017. Vol. 88. Iss. 1. Supplement. P. 189-198. DOI: 10.1007/s11069-017-2853-z
Wei F., Yang H., Hu K., Hong Y., Li X. Two methods for measuring internal velocity of debris flows in laboratory // WIT Transactions on Engineering Sciences. 2012. Vol 73. р. 61-71. DOI: 10.2495/DEB12006
Self-reflection technologies to design the developmental environment for the professional formation of sports teachers
The significance of this article lies in the fact that the problem of modifying the forms, methods and means of implementing the content of education, training and retraining of personnel for the sphere of physical education, sports and tourism always comes first among other pedagogical problems. To improve the educational process and, specifically, educational activities is an essential objective of all the system of education. The article presents the results of a study of the role, place and function of self-reflection in educational activities, as well as in the formation of a sports teacher’s professional thinking based on self-reflective culture of solving professional problems. Based on the logical-substantive analysis, the article shows that the mechanism of self-reflective thinking is mandatory for the formation of the methodological culture of future specialists’ professional thinking in the implementation of the curriculum content of physical education universities; it has been proved that activation of self-reflection during training leads to the fact that the learner makes his own activity as the object of his influence, he begins to purposefully change, improve or rebuild it. In addition, the article substantiates that the modern practice of education, training and retraining of personnel for the field of physical education, sports and tourism requires constant creative improvement of the teaching staff of higher education, which provides solutions to modern educational problems, the resolution of which will prepare competitive specialists for the open labour market; the analysis of a great number of scientific literature sources shows that psych didactics of developmental education should be based on activation of self-reflection, as a special way and means of forming self-reflective culture of sports teachers; the introduction of self-reflection in the educational process determines the improvement of the methodological culture and the personal inclusion of students, which undoubtedly leads to an increase in their professional competence
Results of the COVID-19 mental health international for the general population (COMET-G) study.
INTRODUCTION: There are few published empirical data on the effects of COVID-19 on mental health, and until now, there is no large international study. MATERIAL AND METHODS: During the COVID-19 pandemic, an online questionnaire gathered data from 55,589 participants from 40 countries (64.85% females aged 35.80 ± 13.61; 34.05% males aged 34.90±13.29 and 1.10% other aged 31.64±13.15). Distress and probable depression were identified with the use of a previously developed cut-off and algorithm respectively. STATISTICAL ANALYSIS: Descriptive statistics were calculated. Chi-square tests, multiple forward stepwise linear regression analyses and Factorial Analysis of Variance (ANOVA) tested relations among variables. RESULTS: Probable depression was detected in 17.80% and distress in 16.71%. A significant percentage reported a deterioration in mental state, family dynamics and everyday lifestyle. Persons with a history of mental disorders had higher rates of current depression (31.82% vs. 13.07%). At least half of participants were accepting (at least to a moderate degree) a non-bizarre conspiracy. The highest Relative Risk (RR) to develop depression was associated with history of Bipolar disorder and self-harm/attempts (RR = 5.88). Suicidality was not increased in persons without a history of any mental disorder. Based on these results a model was developed. CONCLUSIONS: The final model revealed multiple vulnerabilities and an interplay leading from simple anxiety to probable depression and suicidality through distress. This could be of practical utility since many of these factors are modifiable. Future research and interventions should specifically focus on them
Novel Bis-Ammonium Salts of Pyridoxine: Synthesis and Antimicrobial Properties
A series of 108 novel quaternary bis-ammonium pyridoxine derivatives carrying various substituents at the quaternary nitrogen’s and acetal carbon was synthesized. Thirteen compounds exhibited antibacterial and antifungal activity (minimum inhibitory concentration (MIC) 0.25–16 µg/mL) comparable or superior than miramistin, benzalkonium chloride, and chlorhexidine. A strong correlation between the lipophilicity and antibacterial activity was found. The most active compounds had logP values in the range of 1–3, while compounds with logP > 6 and logP < 0 were almost inactive. All active compounds demonstrated cytotoxicity comparable with miramistin and chlorhexidine on HEK-293 cells and were three-fold less toxic when compared to benzalkonium chloride. The antibacterial activity of leading compound 5c12 on biofilm-embedded Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli or Pseudomonas aeruginosa was comparable or even higher than that of the benzalkonium chloride. In vivo 5c12 was considerably less toxic (LD50 1705 mg/kg) than benzalkonium chloride, miramistine, and chlorhexidine at oral administration on CD-1 mice. An aqueous solution of 5c12 (0.2%) was shown to be comparable to reference drugs efficiency on the rat’s skin model. The molecular target of 5c12 seems to be a cellular membrane as other quaternary ammonium salts. The obtained results make the described quaternary bis-ammonium pyridoxine derivatives promising and lead molecules in the development of the new antiseptics with a broad spectrum of antimicrobial activity
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Results of the COVID-19 mental health international for the health professionals (COMET-HP) study: depression, suicidal tendencies and conspiracism.
IntroductionThe current study aimed to investigate the rates of anxiety, clinical depression, and suicidality and their changes in health professionals during the COVID-19 outbreak.Materials and methodsThe data came from the larger COMET-G study. The study sample includes 12,792 health professionals from 40 countries (62.40% women aged 39.76 ± 11.70; 36.81% men aged 35.91 ± 11.00 and 0.78% non-binary gender aged 35.15 ± 13.03). Distress and clinical depression were identified with the use of a previously developed cut-off and algorithm, respectively.Statistical analysisDescriptive statistics were calculated. Chi-square tests, multiple forward stepwise linear regression analyses, and Factorial Analysis of Variance (ANOVA) tested relations among variables.ResultsClinical depression was detected in 13.16% with male doctors and 'non-binary genders' having the lowest rates (7.89 and 5.88% respectively) and 'non-binary gender' nurses and administrative staff had the highest (37.50%); distress was present in 15.19%. A significant percentage reported a deterioration in mental state, family dynamics, and everyday lifestyle. Persons with a history of mental disorders had higher rates of current depression (24.64% vs. 9.62%; p < 0.0001). Suicidal tendencies were at least doubled in terms of RASS scores. Approximately one-third of participants were accepting (at least to a moderate degree) a non-bizarre conspiracy. The highest Relative Risk (RR) to develop clinical depression was associated with a history of Bipolar disorder (RR = 4.23).ConclusionsThe current study reported findings in health care professionals similar in magnitude and quality to those reported earlier in the general population although rates of clinical depression, suicidal tendencies, and adherence to conspiracy theories were much lower. However, the general model of factors interplay seems to be the same and this could be of practical utility since many of these factors are modifiable
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The effect of different degrees of lockdown and self-identified gender on anxiety, depression and suicidality during the COVID-19 pandemic: Data from the international COMET-G study.
IntroductionDuring the COVID-19 pandemic various degrees of lockdown were applied by countries around the world. It is considered that such measures have an adverse effect on mental health but the relationship of measure intensity with the mental health effect has not been thoroughly studied. Here we report data from the larger COMET-G study pertaining to this question.Material and methodsDuring the COVID-19 pandemic, data were gathered with an online questionnaire from 55,589 participants from 40 countries (64.85% females aged 35.80 ± 13.61; 34.05% males aged 34.90±13.29 and 1.10% other aged 31.64±13.15). Anxiety was measured with the STAI, depression with the CES-D and suicidality with the RASS. Distress and probable depression were identified with the use of a previously developed cut-off and algorithm respectively.Statistical analysisIt included the calculation of Relative Risk (RR), Factorial ANOVA and Multiple backwards stepwise linear regression analysis RESULTS: Approximately two-thirds were currently living under significant restrictions due to lockdown. For both males and females the risk to develop clinical depression correlated significantly with each and every level of increasing lockdown degree (RR 1.72 and 1.90 respectively). The combined lockdown and psychiatric history increased RR to 6.88 The overall relationship of lockdown with severity of depression, though significant was small.ConclusionsThe current study is the first which reports an almost linear relationship between lockdown degree and effect in mental health. Our findings, support previous suggestions concerning the need for a proactive targeted intervention to protect mental health more specifically in vulnerable groups
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Results of the COVID-19 mental health international for the general population (COMET-G) study.
IntroductionThere are few published empirical data on the effects of COVID-19 on mental health, and until now, there is no large international study.Material and methodsDuring the COVID-19 pandemic, an online questionnaire gathered data from 55,589 participants from 40 countries (64.85% females aged 35.80 ± 13.61; 34.05% males aged 34.90±13.29 and 1.10% other aged 31.64±13.15). Distress and probable depression were identified with the use of a previously developed cut-off and algorithm respectively.Statistical analysisDescriptive statistics were calculated. Chi-square tests, multiple forward stepwise linear regression analyses and Factorial Analysis of Variance (ANOVA) tested relations among variables.ResultsProbable depression was detected in 17.80% and distress in 16.71%. A significant percentage reported a deterioration in mental state, family dynamics and everyday lifestyle. Persons with a history of mental disorders had higher rates of current depression (31.82% vs. 13.07%). At least half of participants were accepting (at least to a moderate degree) a non-bizarre conspiracy. The highest Relative Risk (RR) to develop depression was associated with history of Bipolar disorder and self-harm/attempts (RR = 5.88). Suicidality was not increased in persons without a history of any mental disorder. Based on these results a model was developed.ConclusionsThe final model revealed multiple vulnerabilities and an interplay leading from simple anxiety to probable depression and suicidality through distress. This could be of practical utility since many of these factors are modifiable. Future research and interventions should specifically focus on them
Recommended from our members
Results of the COVID-19 mental health international for the health professionals (COMET-HP) study: depression, suicidal tendencies and conspiracism.
INTRODUCTION: The current study aimed to investigate the rates of anxiety, clinical depression, and suicidality and their changes in health professionals during the COVID-19 outbreak. MATERIALS AND METHODS: The data came from the larger COMET-G study. The study sample includes 12,792 health professionals from 40 countries (62.40% women aged 39.76 ± 11.70; 36.81% men aged 35.91 ± 11.00 and 0.78% non-binary gender aged 35.15 ± 13.03). Distress and clinical depression were identified with the use of a previously developed cut-off and algorithm, respectively. STATISTICAL ANALYSIS: Descriptive statistics were calculated. Chi-square tests, multiple forward stepwise linear regression analyses, and Factorial Analysis of Variance (ANOVA) tested relations among variables. RESULTS: Clinical depression was detected in 13.16% with male doctors and 'non-binary genders' having the lowest rates (7.89 and 5.88% respectively) and 'non-binary gender' nurses and administrative staff had the highest (37.50%); distress was present in 15.19%. A significant percentage reported a deterioration in mental state, family dynamics, and everyday lifestyle. Persons with a history of mental disorders had higher rates of current depression (24.64% vs. 9.62%; p < 0.0001). Suicidal tendencies were at least doubled in terms of RASS scores. Approximately one-third of participants were accepting (at least to a moderate degree) a non-bizarre conspiracy. The highest Relative Risk (RR) to develop clinical depression was associated with a history of Bipolar disorder (RR = 4.23). CONCLUSIONS: The current study reported findings in health care professionals similar in magnitude and quality to those reported earlier in the general population although rates of clinical depression, suicidal tendencies, and adherence to conspiracy theories were much lower. However, the general model of factors interplay seems to be the same and this could be of practical utility since many of these factors are modifiable
The effect of different degrees of lockdown and self-identified gender on anxiety, depression and suicidality during the COVID-19 pandemic: Data from the international COMET-G study.
INTRODUCTION: During the COVID-19 pandemic various degrees of lockdown were applied by countries around the world. It is considered that such measures have an adverse effect on mental health but the relationship of measure intensity with the mental health effect has not been thoroughly studied. Here we report data from the larger COMET-G study pertaining to this question. MATERIAL AND METHODS: During the COVID-19 pandemic, data were gathered with an online questionnaire from 55,589 participants from 40 countries (64.85% females aged 35.80 ± 13.61; 34.05% males aged 34.90±13.29 and 1.10% other aged 31.64±13.15). Anxiety was measured with the STAI, depression with the CES-D and suicidality with the RASS. Distress and probable depression were identified with the use of a previously developed cut-off and algorithm respectively. STATISTICAL ANALYSIS: It included the calculation of Relative Risk (RR), Factorial ANOVA and Multiple backwards stepwise linear regression analysis RESULTS: Approximately two-thirds were currently living under significant restrictions due to lockdown. For both males and females the risk to develop clinical depression correlated significantly with each and every level of increasing lockdown degree (RR 1.72 and 1.90 respectively). The combined lockdown and psychiatric history increased RR to 6.88 The overall relationship of lockdown with severity of depression, though significant was small. CONCLUSIONS: The current study is the first which reports an almost linear relationship between lockdown degree and effect in mental health. Our findings, support previous suggestions concerning the need for a proactive targeted intervention to protect mental health more specifically in vulnerable groups