δ15N in Birch and Pine Leaves in the Vicinity of a Large Copper Smelter Indicating a Change in the Conditions of Their Soil Nutrition

δ13C and δ15N were analyzed in the leaves of Pinus sylvestris L. and Betula spp. under the conditions of severe heavy metal (Zn, Cu, Cd, and Pb) contamination. Twenty-seven plots located near the Karabash copper smelter (Russia) were studied. No reliable correlation of 13C in tree leaves with the level of pollution was observed. δ15N, both in Pinus sylvestris and Betula spp., increased similarly in polluted areas. δ15N was increased by 2.3‰ in the needles of Pinus sylvestris and by 1.6‰ in the leaves of Betula spp. in polluted plots compared to the background ones. The probable reasons for the increase in δ15N were estimated using multiple regression. The regression model, which includes two predictors: δ15N in the humus horizon and the occurrence of roots in the litter, explains 33% of the total variability of δ15N in leaves. Thus, in ecosystems polluted with heavy metals, the state of trees is determined not only by the direct toxic effects of heavy metals but also by indirect ones associated with the features of plant mineral nutrition. This fact opens the way to the search for opportunities to control the state of plants in disturbed ecosystems by regulating the content of mineral nutrition elements. © 2022 by the authors

Theory of differential inclusions and its application in mechanics

The following chapter deals with systems of differential equations with discontinuous right-hand sides. The key question is how to define the solutions of such systems. The most adequate approach is to treat discontinuous systems as systems with multivalued right-hand sides (differential inclusions). In this work three well-known definitions of solution of discontinuous system are considered. We will demonstrate the difference between these definitions and their application to different mechanical problems. Mathematical models of drilling systems with discontinuous friction torque characteristics are considered. Here, opposite to classical Coulomb symmetric friction law, the friction torque characteristic is asymmetrical. Problem of sudden load change is studied. Analytical methods of investigation of systems with such asymmetrical friction based on the use of Lyapunov functions are demonstrated. The Watt governor and Chua system are considered to show different aspects of computer modeling of discontinuous systems

Study on the influence of the magnetron power supply on the properties of the silicon nitride films

Silicon nitride (Si3N4) films were deposited by magnetron sputtering of silicon target in (Ar+N2) atmosphere with refractive index 1.95 - 2.05. The results of Fourier transform infrared (FTIR) spectrophotometry showed Si-N bonds in the thin films with concentration 2.41·1023 - 3.48·1023 cm-3. Dependences of deposition rate, optical characteristics and surface morphology on rate of N2 flow and properties of magnetron power supply

Clinical and methodological aspects in the diagnosis of magnesium deficiency in patients with paroxysmal atrial fibrillation

Aim. To determine magnesium deficiency in patients with paroxysmal atrial fibrillation using a comprehensive clinical and laboratory approach. Methods. The prospective cohort study included 35 patients of the cardiology department of the Medical association «Novaya bolnitsa». The main group consisted of 22 patients with frequently recurrent paroxysmal atrial fibrillation, the control group - 13 patients without cardiac arrhythmias. The clinical status, Holter-monitoring of the electrocardiogram, the results of the clinical test for magnesium deficiency, laboratory parameters of calcium, magnesium in blood plasma and formed elements, magnesium in whole blood, free fatty acids and plasma osmolarity were evaluated. Results. The clinical score of magnesium deficiency was significantly higher in patients from the main group compared to the control [16.5 (11÷21) vs 13 (8÷15), p <0.001]. In the main group, there was a decrease of magnesium in the whole blood [0.55 (0.5÷0.59) vs 0.61 (0.58÷0.54), p=0.002] and inside the blood cells [0.68 (0.53÷1.29) vs 1.38 (1.29÷1.44), p <0.001]. In patients with atrial fibrillation there is a shift of the ratio of calcium to magnesium in blood plasma [2.5 (2.5÷3) vs 2.9 (2.8÷3.15), p=0.029] and intracellularly [4.85 (2.62÷9.3) vs 1.7 (1.4÷1.95), p=0.002]. The redistribution of calcium and magnesium is influenced not only by the initial concentration of cations, but also by free fatty acids. The best redistribution was obtained when the concentration of free fatty acids was 900 µmol/l, magnesium 1 mmol/l, and calcium 3 mmol/l, which is consistent with the optimal value of cations in the blood plasma. Conclusion. Patients with paroxysmal atrial fibrillation had a significantly lower magnesium content in whole blood and inside the blood cells; magnesium concentration in the cells and in whole blood closely correlated with the results of the clinical test for evaluating magnesium deficiency; intracellular magnesium content can be influenced by the complexing interaction with free fatty acids

Specific nature of the integrative (complex) effect of environmental factors on hazelnut cultivars in the Russian humid subtropics

Corylus pontica K. Koch is a valuable nut crop. The expediency of the crop’s large-scale cultivation calls for measuring the parameters of agroclimatic indicators, ranging in variability, intensity, and duration of their impact. Environmental factors were assessed using phenological techniques based on recording the flowering and fruiting dates, recognized as the function demonstrating the complex effect of these factors on the hazelnut yield throughout the crop’s perennial cycle. Climate change urges the selection of adaptable cultivars for such areas where limiting factors are turning into stressors. Dependence of hazel cultivars on climate indicators (air temperature and humidity, and total precipitation) was observed in the phases of harvest formation. The crop’s genotypic diversity contributed to the specific nature of the complex effect produced by environmental factors. Peculiar responses of hazel plants to weather conditions in both flowering and fruiting phases were instigated by the biology of their development. Flowering started in January and depended on air temperature and humidity. Fruiting was affected by air temperatures and precipitation amounts (in July/August). Dependencies between yield and weather were well expressed, with module values of 0.86–1.0 (p &lt; 0.05). The effect size of limiting factors is better measured with the coefficient of determination (%), a direct indicator of the correlations between harvest and weather factors. Flowering (I–III) under unpredictable conditions is regarded as a “critical” stage in the ontogenesis of hazel trees. No less critical is the fruiting phase, occurring simultaneously with the setting and differentiation of generative organs for the next year’s yield. Registration of limiting factors and their variations over the perennial plant cycle made it possible to recommend cvs. ‘Cherkesskiy-2’, ‘Anastasiya’, ‘Kristina’ and ‘Viktoriya’ as adaptable to the subtropics of Krasnodar Territory

HUMUS GAZHEVYH FLOODPLAIN SOILS OF SOUTHERN PRIANGARYE

In the South Angara Region in special conditions formed gazhevye soil. They inherited soil from carbonate rocks and groundwater. Soil- matter rocks are represented by the Upper Cambrian dolomite and gypsum. These soils are characterized by a high content of gypsum in gazhevyh horizons. On the content of soil organic matter are nizkogumusnym and-moderate soils

The peculiarities of oral cavity and its subjective estimation of women with PCOS

The article presents the results of research the aim of which was describing of the peculiarities of oral cavity and its subjective estimation by women with PCOS. On the sample of 50 subjects with PCOS (diagnosed in accordance with Rotterdam consensus] we used the following: oral cavity examination: Gingeval Index, CPITN calculations and WHO questionnaires on oral cavity health for adults. As a result of oral cavity examination we have not found any serious pathology, but 20 % of patients demonstrated gingival bleeding. At the same time, the self-estimation of oral cavity conditions by women with PCOS was "satisfactory" in 34 %, "good" - in 44 % and "excellent" in 22 %. The indices recommended by WHO for estimation of oral cavity conditions (CPITN and GI] were generally within the normal ranges and characterized oral cavity status of the women with PCOS as good. However, in PCOS patients with high degree of gum bleeding the CPITN and GI indexes were increased, and these patients reported that they visited а dentist more frequently. Changes in the condition of the oral cavity in PCOS were not associated with any specific behavior of women in the care of teeth and oral cavity. The authors suggest that additional investigation of microbiome should be done for further more comprehensive analysis of oral cavit

Parameters of blood pressure during stress test in young elite athletes

It is known that in children at rest, BP values depend on height, but this aspect is not taken into account when analyzing the maximum BP during exercise.Objective: to determine the maximum value of BP in young elite athletes, depending on height and gender.Materials and methods: 2313 (age 15.5 ± 1.4 years, 45% of young men) young elite athletes, members of national teams of the Russian Federation in 40 sports, were examined. All subjects underwent bicycle ergometry according to the PWC170 protocol, blood pressure was measured manually at each stage of the load, and its maximum values were determined during the entire test.Results: The maximum BP values in boys were higher than in girls: systolic blood pressure (SBP) 195 ± 25 vs 175 ± 20 mmHg, p &lt; 0.001, diastolic blood pressure (DBP) 80 ± 11 vs 80 ± 10 mm Hg, p &lt; 0.05. A relationship was found between the maximum value of blood pressure on load and growth (r = 0.55; p &lt; 0.001). Normative tables are proposed for assessing the maximum values of SBP and load, depending on growth.Conclusion: In young elite athletes, the maximum BP value during VEM according to the PWC170 protocol depends not only on gender, but also on height. The maximum values of SBP during exercise in tall young elite athletes can reach 250 mm Hg in boys and 210 mm Hg in girls

МЕТОДИКА ОПРЕДЕЛЕНИЯ ИЗОТОПНЫХ ОТНОШЕНИЙ Cu И Zn МЕТОДОМ МК ИСП-МС С ИСПОЛЬЗОВАНИЕМ СМОЛЫ AG MP-1

The isotopic composition of copper is of great interest for researchers in various fields of science, geochemistry and hydrology in particular, wherein the consideration is being given to the variations in the isotopic composition of the Earth's crust, extraterrestrial matter, and water basins, as well as to the origin and transfer of matter. Zn isotopes appear to be promising for identifying the sources and pathways of the environmental pollution. The aim of this study involves the refinement and validation of the zinc and copper isotopic ratio determination methodology covering the whole process from sample digestion to MC ICP-MS measurements. For this reason, as well as to assess the suitability of the methodology for the analysis of environmental samples, Zn and Cu isotopic analysis of the BHVO-2, BCR-2 and AGV2 USGS certified reference materials has been performed. The method for determination of Cu and Zn stable isotope ratios by multi-collector inductively coupled plasma mass spectrometry in environmental samples is developed. The application of the AG MP1 resin with optimized layer parameters (resin bed height 3.5 cm, diameter 1 cm) provides the highpurity Cu and Zn fractions. The method is characterized by high throughput and adequate analytical figures of merit when using the standardsample bracketing technique for mass bias correction. The procedural blanks related to chemical dissolution and ion exchange procedures are lower than 1 and 3 ng for Cu and Zn, respectively, assuring no blank effect on the isotopic composition of samples. The accuracy and precision obtained for Cu and Zn isotope measurements in the BHVO2, BCR2 and AGV2 geological certified reference materials demonstrate good agreement with the reference values published. © 2022 Institute of the Earth's Crust. All rights reserved.ААААА181180530900458; Ministry of Education and Science of the Russian Federation, Minobrnauka: 075-15-2021-680; Russian Science Foundation, RSF: 18-77-10024The work of Okuneva T.G. is supported by the Russian Science Foundation (project 18-77-10024), the rest authors are supported by the state assignment of the IGG UB RAS ААААА181180530900458. Isotopic analyses are performed at the "Geoanalitik" Shared Research Facilities of the IGG UB RAS. The reequipment and comprehensive development of the "Geoanalitik" Shared Research Facilities of the IGG UB RAS is financially supported by the grant of the Ministry of Science and Higher Education of the Russian Federation (Agreement 075-15-2021-680).authors are supported by the state assignment of the IGG UB RAS ААААА 猃?猃猃稃爃眃甃爃笃爃爃瘃?稁 Isotopic analyses are performed at the 㘀Geoanalitik ? Shared Research Facilities of the IGG UB RAS. The reequipment and comprehensive development of the 㘀Geoanalitik 㘀 Shared Research Facilities of the IGG UB RAS is 퀀inancially supported by the grant of the Ministry of Science and Higher Education of the Russian Federation (Agreement 075-15-2021-680).FUNDING: The work of Okuneva T.G. is supported by the Russian Science Foundation (project 18-77-10024), the res