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In the paper, we prove probabilistic analogs of the universal approximation theorems and link continuous random variables of a certain type and monotonic feedforward artificial neural networks with one-dimensional input, output and one hidden layer. In particular, we show that any continuous infinitely divisible random variable can be successfully approximated with a mix of logistic distributions. Based on the theorems proved in the current paper, we develop a new approach for developing Monte Carlo methods combined with artificial neural networks for pricing options in Lévy models. In contrast to straightforward incorporation of neural networks into Monte Carlo methods, we approximate the cumulative distribution function, but not its inverse. Moreover, we give a clear probabilistic interpretation of the constructed approximator that helps us simulate the Lévy process by using only separate components of our neural network., Author(s): Oleg Kudryavtsev [sup.1] [sup.2], Natalia Danilova [sup.1] [sup.2] Author Affiliations: (1) InWise Systems, LLC, , Rostov-on-Don, Russia (2) https://ror.org/01tv9ph92, grid.182798.d, 0000 0001 2172 8170, I.I.Vorovich Institute of Mathematics, Mechanics [...]

Abstract To date, pulmonary fibrosis remains an unmet medical need. In this study, we evaluated the potency of mesenchymal stromal cell (MSC) secretome components to prevent pulmonary fibrosis development and facilitate fibrosis resolution. Surprisingly, the intratracheal application of extracellular vesicles (MSC-EVs) or the vesicle-depleted secretome fraction (MSC-SF) was not able to prevent lung fibrosis when applied immediately after the injury caused by bleomycin instillation in mice. However, MSC-EV administration induced the resolution of established pulmonary fibrosis, whereas the vesicle-depleted fraction did not. The application of MSC-EVs caused a decrease in the numbers of myofibroblasts and FAPa+ progenitors without affecting their apoptosis. Such a decrease likely occurred due to their dedifferentiation caused by microRNA (miR) transfer by MSC-EVs. Using a murine model of bleomycin-induced pulmonary fibrosis, we confirmed the contribution of specific miRs (miR-29c and miR-129) to the antifibrotic effect of MSC-EVs. Our study provides novel insights into possible antifibrotic therapy based on the use of the vesicle-enriched fraction of the MSC secretome.

The paper presents a method for calculating a portfolio with a guaranteed return at a given confidence level. The portfolio is calculated using a sample of the returns of the assets included in the portfolio. The problem is considered in a nonparametric statistical setting, that is, the assumptions were not made on the distribution law of the return vector, and a parametric statistical setting with normal law distribution. The main elements of the method are an ellipsoid of minimum volume containing a given number of sample elements and a method for calculating it. The minimum size ellipsoid containing a sample has long been used in mathematical statistics to obtain robust estimates of the mean and covariance matrix, as well as in machine learning, so its application for an optimal portfolio looks natural., Author(s): Grigory Beliavsky [sup.1], Natalia Danilova [sup.1] Author Affiliations: (1) grid.182798.d, 0000 0001 2172 8170, Vorovich Institute of Mathematics, Mechanics and Computer Sciences, South Federal University, , Milchakova st., 8a, [...]

Biosurfactants are one of the promising biotechnological products applied in agriculture. Their use, however, is currently far from economically viable, due to the expensive feedstock for the growth of microorganisms. The solution to this problem can be to reduce the cost of production by using organic waste as a nutrient substrate. In this study, oil-containing wastes were considered as substrates - waste frying sunflower oil and petroleum-contaminated soil. At the first stage of research, we screened native waste microorganisms capable of synthesizing biosurfactants. As a result of the study, strains with the ability to form biosurfactants were isolated. Six strains (A, B, C, D, E, F) were isolated from waste frying sunflower oil, two strains (A1, B1) were isolated from petroleum-contaminated soil. The highest yield of biosurfactants is typical for strains A and A1 - 0.429 and 0.502 mg ml-1, while the best ratio of biosurfactant mass to cell biomass is typical for strains A1 and E - 0.9 and 0.6. The most effective producer of biosurfactants turned out to be strain E with an emulsifying activity of E24 equal to 80% and a surface tension of the culture liquid of 27.1 mN m-1.

The emission of carbon dioxide from the soil is an urgent problem, as it not only contributes to climate change, but also affects the reduction of the carbon pool in the soil, which negatively affects its fertility. Cultivation of crops with fast growth, high biomass and atmospheric carbon fixation capacity is effective in terms of reducing soil carbon dioxide emissions and organic carbon storage. The purpose of this work was to evaluate greenhouse gas emissions from the cultivation of industrial hemp (Cannabis sativa L., 1753) in different temperature regimes – 15ºС, 20ºС and 30ºС. Soil without plants was used as a control. The respiration activity of the soil microbial community was assessed on the 1st, 7th, 14th, 28th, 42nd, 56th, 70th, 84th and 98th days of incubation. Biomass of plants was measured on the 98th day. It was established that there were no differences in the respiration activity of the control soil and the soil under industrial hemp (Cannabis sativa L., 1753) at the beginning of the experiment, however, from the 14th day, the respiration activity was significantly lower in the soil without plants. The influence of the temperature regime on respiration activity was established after 56 days of the experiment. The influence of the temperature regime of vegetation on the morphometric parameters of hemp has been established: the largest biomass of plants was found at a colder incubation temperature (15ºС). It has been established that the emission of greenhouse gases from the soil during the cultivation of industrial hemp (Cannabis sativa L., 1753) is higher compared to pure soil and depends on the temperature regime.

The article is devoted to the identification of symbolic markers and perception of the cognitive model of the space of the northern cities of the Republic of Sakha (Yakutia). The definition of “northern cities” is constructed based on the results of a study to identify various aspects of identity (national, territorial, ethnocultural) and is used by the authors when defining all cities of Yakutia. The main tools for constructing and regulating the cognitive map of a city are city monuments associated with historical memory and acting as components of state policy and a nation-building tool. The main research methods were historical and cognitive analysis and the method of questionnaire survey. The novelty of the article is a cross-cultural study of the perception of urban monuments as symbolic markers of urban space. The authors observe a difference in the perception of the symbolism of urban space between generational groups. It is concluded that each city, depending on its geographical and economic location, local characteristics, and national identity, has its own specific set of symbolic markers in the cognitive map of the city. The findings will contribute to the systematic study of the value attitudes of residents of modern Russian cities. Multilevel models of symbolic images associated with both national and territorial identities are being built.

The paper considers the problem of optimal control in models with disorder and provides the computational scheme of its solution. The proposed method is based on replacing the disorder with its estimate by the stopping time. The calculations take place on the binary tree with nodes divided into two classes. The division of tree nodes into two classes is carried out using a decision rule associated either with testing two hypothesis, or with the optimal stopping of a Markov process developing on a binary tree. The estimate of the disorder is the moment at which the walk on the tree is placed in a node of the first class for the first time. The example of the optimal control problem is related to the problem of quantile hedging of a payoff. [ABSTRACT FROM AUTHOR]

Aim. The aim of the research is to study the symbolic capital of northern cities (semiotic potential) contained in "urban texts" and the influence of the historical memory of a multiethnic region on the political process of the region and the country as a whole, through a comprehensive and interdisciplinary study of the symbolic space of cities in the Republic of Sakha (Yakutia). Methods. The study used the cognitive approach, the method of space-time analysis, and the method of historicism and questionnaire survey. Symbolic space as a text is a heterogeneous content. Results. The results of the study show the importance of a symbolic resource as a brand tool, first, depending on the political context and introduction into the collective memory through a constant "reminder" of its importance and significance in the socio- -cultural and everyday life of citizens. The resulting databases of monuments served as the basis for compiling a virtual album of monuments and art objects in the cities of the Republic of Sakha (Yakutia). The research results can practically be applied in the field of education, politics, culture, in the study and promotion of the cultural and historical heritage of the regions of Russia. Conclusions. The urgent problem is the task of preserving the accumulated experience and values, places of memory, relics of the past, as well as ideas about the past that are stored in the memory of its inhabitants and the transfer of this knowledge to the younger generation. [ABSTRACT FROM AUTHOR]