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Identification of tephra and its allocation (association) with known eruptive events allows obtainng chronostratigraphic markers, on the basis of which an age scale for dating glacial strata can be developed. To determine the sources of ash in the ice core obtained in 2022 during drilling of glacier in the crater of the Ushkovsky volcano in Kamchatka, the chemical composition of volcanic glass in individual ash particles was analyzed. The accuracy of determination of the volcanic glass composition was verified by analyzing of international standard samples of volcanic and synthetic glass. Based on a comparison of the data we obtained with published data on the composition of tephra glasses from the present-day eruptions in Kamchatka, we determined affiliation of each tephra horizon to specific volcano-source. We have found that the main source of tephra in the ice core of the Ushkovsky Glacier is the Kliuchevskoi volcano, which is the closest and the most productive one among the Kamchatka volcanoes. Ash particles from Bezymyannyi volcano were identified in two horizons. A mixed population of particles was found in one of the horizons, including the ash particles from volcanoes Kizimen, Kliuchevskoi and Bezymyannyi. Analysis of published data on the chronology and distribution of ash plumes from known eruptive events made it possible to confidently correlate the tephra horizon at a depth of 762–777 cm with the initial phase of the eruption of the Kizimen volcano in late 2010–early 2011. Ash from the uppermost tephra buried in the glacier at depths of 89–94 cm belongs to the Bezymyannyi volcano eruption, which the most likely occurred in October 2020. Single particles with rhyolitic composition of glass in the sample from the depth of 348–354 cm may belong to the eruption of the Shiveluch volcano in December 2018. The results of our work can be used on further studying of the ice core from the Ushkovsky volcano, in particular for comparison and correlation with the chronostratigraphic data obtained by glacio-chemical and isotope methods.

Retinopathy of prematurity (ROP) is a complex and unresolved problem in pediatric ophthalmology, leading to visual disability. Low birth weight and prematurity are the main risk factors, and they form the basis of clinical recommendations for screening for ROP in all children under 35 weeks of gestational age and weighing less than 2000 g. However, many researchers point to other risk factors that can be divided into maternal, prenatal and perinatal. In this review, we consider maternal diabetes mellitus as a risk factor for ROP. Changes in the retina in premature infants and mothers with diabetes mellitus have some common features, since pathological angiogenesis occurs at the basis of these diseases. In addition, diabetes is a risk factor for preterm birth, and prematurity is a leading cause of neonatal morbidity, including the development of ROP. This suggests that maternal diabetes mellitus may have both direct and indirect effects on the development of ROP. To develop predictive models, an understanding of risk factors for ROP, the pathophysiology of retinal vascular diseases, and diseases of prematurity is necessary.

One of the crucial factors affecting the safety and regularity of state and civil aviation flights is the meteorological situation. The European territory of Russia is most characterized by dangerous meteorological phenomena associated with cumulonimbus clouds: shower, thunderstorms, hail, accompanied by high atmospheric turbulence. Currently, meteorological radar stations are an indispensable source of information about the weather situation for air transport. The criteria for the classification of meteorological phenomena used in modern radar stations are formed for each event separately and are based on knowledge only about the altitude distribution of radar reflectivity and air temperature, despite the fact that radar data assess the wind characteristics of the atmosphere. It is shown that optimization of the classification criteria for the mentioned meteorological phenomena should be realized by generalization of the criteria and their construction in accordance with the theory of statistical hypothesis distinction, as well as by additional use of information on atmospheric turbulence. Based on the analysis of radar signals reflected from the meteorological events of shower, thunderstorm, and hail, probability distributions of reflectivity and specific dissipation rate of turbulent energy were obtained. Statistical analysis of probability distribution densities was carried out for: the maximum value of reflectivity Zmax, its dependence on height H(Zmax), as well as the maximum specific dissipation rate of turbulent energy EDRmax and the value H(EDRmax). The classification criterion based on the maximum probability functional was chosen to determine the structure of classification algorithms and decision rules. At the same time under the acceptable confidence is accepted the value of the probability of correct classification not lower than 0.8. For the accepted criterion the decision thresholds are constructed and the complete matrices of classification probabilities are calculated. The results of calculations showed that the worst informativeness in the classification of dangerous meteorological events of cumulonimbus cloudiness have parameters H(Zmax), H(EDRmax). Parameters Zmax, EDRmax have greater separating ability, but even for them the confidence of classification is unacceptable. In the article to increase the confidence of classification the joint use of features in the form of multivariate probability distribution densities of information parameters was applied. The best results are achieved when three p(Zmax,H(Zmax),EDRmax) and four p(Zmax,H(Zmax),EDRmax,H(EDRmax)) features are used. In the probability matrices for these cases, the maximum and acceptable at 0.8 level of probabilities of correct classification are achieved. Thus, the expansion of the feature space due to atmospheric turbulence is justified in the problem under consideration. These results will be refined with increasing observation time and will vary for different climatic zones. In general, the decision thresholds for classifying dangerous meteorological events of cumulonimbus cloudiness should be adaptive.

Disorder of the formation of the cavum septum pellucidum (CSP) occurs in a wide range of pathologies of the brain. Its identification from 18 to 37 weeks is a necessary rule of prenatal screening, which must also be performed in postnatal studies of premature infants. Unimaged CSP should be considered as a potential indicator of cerebral dysfunction and such severe malformations as agenesis (dysgenesis) of the corpus callosum, holoprosencephaly (HPE), schizencephaly, Aicardi syndrome, hydrocephalus and septo-optic dysplasia (SOD). A special place in the differential diagnosis of unimaged CSP is represented by SOD, lobar HPE, and its mild subtype - septopreoptic HPE. The literature describes the isolated absence of SP, without finding other signs related to HPE or SOD, as a variant of development. However, the neurological outcome in these children varies from normal to delayed development of the nervous system by different degrees, so this statement remains controversial. The article discusses in detail the anatomy, physiology, pathology of the septal region, the role of echographic studies in the antenatal and postnatal periods, and the correlation of the detected changes with the clinical picture.

To prevent the spread of COVID-19, to ensure the safety of ourselves and others, personal protective equipment — various types of masks — has firmly entered our daily lives. Purpose to conduct a clinical and sociological study of the severity of the dry eye syndrome in medical personnel and medical students against the background of the use of personal protective equipment and to assess the possibilities of its correction using tear replacement therapy. Materials and methods. 138 medical staff and 149 students were analyzed. A survey was conducted to identify risk factors for the development of the dry eye syndrome. The total tear production was determined using the Schirmer I test at the beginning and after 8 hours of the working day in medical personnel and students before and after a 6-hour lesson. To study the possibility of correcting the dry eye syndrome, students were offered instillations of the tear substitute Gylan 0.18 % 3 times a day. At this stage of the study, 2 questionnaires were used to assess the severity of DES symptoms: OSDI and DEQ, Schirmer I test. Results. Most of the study participants noted the constant wearing of masks (86.4 % of doctors and 84.8 % of nurses). At the beginning of the study, 45.1 % of doctors and 51.9 % of nursing staff, 45.6 % of students had indicators of total tear production below the reference values. At the end of working hours, doctors (90.9 %), nurses (88.6 %) and students (69.2 %) showed a decrease in the total tear production of varying severity. The use of a tear substitute made it possible to increase the indicators of total tear production: 10 days after treatment, an increase was observed in 45.7 % of cases (but the values were in the range of 10—14 mm), in 31.4 % of cases they reached 15 mm or more and exceeded the initial values (p < 0.05); reduce the symptoms of dry eye: the number of students with DEQ questionnaire syndrome dry eye at the beginning of the study (62.9 %) decreased by 3.2 times. Conclusions: the conducted study allows us to speak about the currently available riskfactorfor the development of the dry eye syndrome: personal respiratory protective equipment has a negative impact on the indicators of total tear production. Appointment of tear replacement therapy allowed to improve the functional indicators of tears and quality of life. It is necessary to develop and implement measures aimed at identifying and preventing the development of the dry eye syndrome not only among medical personnel, but also among the population as a whole.