BACKGROUND: Climate change has a significant impact on population health, morbidity, and mortality rates. Studies of the current characteristics of warming and cooling periods occurring during the warm and cold seasons of the year on the Crimean Peninsula will help fill existing gaps in information on the near-surface temperature regime of the peninsula. On the basis of the conducted studies, it is possible to develop approaches to adaptation to climate risks, which include measures to reduce excess mortality from the effects of heat and cold waves. AIM: To determine qualitative and quantitative indicators, as well as the conditions of occurrence and consequences of warming and cooling periods on the Crimean Peninsula during the warm and cold periods of the year. METHODS: The study used standard statistical processing methods and visualization of the obtained results. To determine seasonal warming and cooling periods for the period 2006–2023, thresholds were calculated using the 5% and 95% percentiles of the seasonal distribution of daily temperatures. RESULTS: The greatest variability in temperature is observed in the cold season, with an increase in the number and duration of warming periods and a decrease in the number and duration of cooling periods. The study period is characterized by extreme temperature minima (−33.6 ℃) and maxima (38.6 ℃), which are dangerous for the most vulnerable groups of the population, including half of the peninsula's residents. Because the threshold values for warming periods are lower (compared with mainland indicators), hot events on the peninsula will be tolerated much more easily than in the mainland part of southern Russia. This contributes to the development of year-round climatotherapy centers with comfortable conditions in not only coastal but also mainland locations. For ensuring the economic security of the region, significant factors are the dependence of the peninsula's water and electricity supply on the size of the tourist flow, as well as spring cooling periods with negative air temperatures lasting more than three days, which directly affect the diversity of agricultural crops and their yields. CONCLUSION: A current assessment of the characteristics of seasonal warming and cooling periods on the Crimean Peninsula, using the 5% and 95% percentiles of the seasonal distribution of daily temperatures, made it possible to identify time periods characterized by the maximum risks of negative impact of extreme temperatures on human health on the Crimean Peninsula.
It is known that logistic regression, which is used to establish statistical relationships between a dichotomous response Y (takes two values Y = 0 and Y = 1) and a quantitative predictor X, has an applicability condition, namely, the relationship between the logit of the probability of Y = 1 and predictor X should be linear. This condition is not always met, and verification is required for each specific actual (epidemiological) dataset. However, there is a situation in logistic regression in which the condition of its applicability is met automatically. For this to happen, the values of predictor X in the groups Y = 0 and Y = 1 should be normally distributed with equal variances. In this paper, we investigate the shape of the relationship between the logit of the probability of Y = 1 and X for different variants of a normally distributed X with equal and unequal variances at various ratios between the variances and means of normal distributions. The results of comparing calculations by logistic regression with observed data for these variants are presented, as well as the results when the applicability condition of logistic regression is violated.
BACKGROUND: In the current context of information overload, physical inactivity, and disruptions in diet and nutrition among students, it is important to monitor the dynamics of physical development and the functional state of the respiratory system, as it is the system most vulnerable to the effects of extreme natural and climatic conditions. AIM: To study the dynamics of the functional state of the respiratory system in Yakut young men over the past decade. To conduct a comparative analysis of respiratory parameters in the examined students with normal and excess body weight. METHODS: The study included young men of Yakut ethnicity aged 18 to 21 years (93 participants in 2010 and 90 in 2020–2022). Morphometric parameters (body length and body weight (BW), chest circumference, and body mass index) were determined. The functional state of the external respiratory system was assessed using the Valenta+ hardware and software system and the Spiro-S-100 portable spirograph. RESULTS: The findings showed that over the past decade, there was a trend toward decreased respiratory bronchial patency (FEF75), which determines the adequacy of gas exchange in the lungs. This change was associated with a significant increase in BW in students in 2021–2022 compared with their peers in 2010. A comparative analysis of external respiration parameters in students with different body weights in 2021–2022 revealed reduced airflow in the respiratory bronchioles and a significantly lower expiratory reserve volume in students with excess body weight relative to students with normal body weight, which to a certain extent creates a risk of obstructive and restrictive pulmonary ventilation disorders. CONCLUSION: A significant increase in BW in students over the past 10 years is accompanied by negative changes in lung volumes and airway patency, which reduces the functional capacity of the respiratory system.
BACKGROUND: This article focuses on identifying the most significant markers of the formation of neurophysiological mechanisms underlying sensorimotor responses in children during different developmental periods (5–7 years and 8–12 years). AIM: To identify the most significant neurophysiological markers based on electroencephalography, sensory, and endogenous evoked potentials in sensorimotor reactions in children of different ages using regression models. METHODS: The inclusion criteria were parental and child consent to participate in the study, the presence of benign epileptiform patterns of childhood on the electroencephalogram, and the child’s ability to perform the study test tasks. The exclusion criteria were acute and chronic diseases of a neurological or psychiatric profile, including epileptic encephalopathy and developmental encephalopathy, and a history of injuries to the central and peripheral nervous systems. Electroencephalography, sensory and endogenous evoked potentials were used as markers of the activity of neurophysiological mechanisms that form sensorimotor reactions in children. Linear regression analysis was used to identify the most significant electrophysiological markers of the forming neurophysiological mechanisms in children aged 5 to 12 years. RESULTS: The findings showed that the most significant indicators characterizing the age-related formation of neurophysiological mechanisms that ensure children’s interaction with the environment are the alpha rhythm of the electroencephalogram recorded in the specific zones of the cerebral hemispheres of the corresponding sensory system and the latency of the P300 evoked potential. CONCLUSION: Based on the data obtained, models were proposed for the dependence of the latency of the P300 potential and the frequency of the basic rhythm on the child’s age, reflecting age-related neurophysiological characteristics.
BACKGROUND: Acid-base balance (pH) is one of the key parameters of the body's internal environment. This indicator changes most dynamically in the gastrointestinal tract, where sharp fluctuations in acidity are not a random process, but a finely regulated and vital mechanism. Each section of the gastrointestinal tract functions within a strictly defined pH range, which ensures efficient digestion of food, destruction of pathogenic microorganisms, and absorption of nutrients. Another important function of the gastrointestinal tract is the binding of heavy metal ions from food and water. To address this issue, new, highly effective sorbents are being developed. A promising source for their creation is raw materials of animal origin, in particular, the horns of cattle and antlers of reindeer. The materials obtained from them demonstrate high sorption activity with respect to toxic ions, which opens up possibilities for their use both in a new generation of enterosorbents for detoxification and in environmental purification systems. AIM: To study the influence of temperature and pH on the sorption capacity of reindeer antler tissue. METHODS: Biopolymer samples (reindeer antler tissue) were selected as the study objects. Direct potentiometry was used in the study. RESULTS: According to the studies, the sorption activity of reindeer antler bone tissue depends on temperature and pH of the medium. Specifically, with an increase in pH, a decrease in the adsorption of Zn2+ ions is observed, while the adsorption of Pb2+ ions, conversely, increases. It was also noted that the pH of the medium has a positive effect on the binding capacity coefficients of both metals. In turn, an increase in temperature leads to a decrease in the sorption capacity constants for Pb2+ and Zn2+ ions. CONCLUSION: The results of the study confirm the scientific and practical importance of studying natural biopolymers as functional sorbents and create the basis for further developments in the field of medical biotechnology, toxicology, and environmental hygiene.
