Influence of Chronic Radiation Exposure on the Temporal Dynamics of Seeds Germination in Scots Pine Populations from the Bryansk Region Affected By the Chernobyl Accident

Temporal dynamics of seeds germination in Scots pine populations growing in theBryansk region of Russia radioactively contaminated as a result of the Chernobyl accident were investigated over a period of 8 years (2008-2015). In contrast to cytogenetic effects in Scots pine, we failed to detect any significant impact of chronic radiation exposure on time dynamics of seeds germination. Keywords: Scots pine, Chernobyl accident, chronic exposure, temporal dynamics, seeds germinatio

Modeling interactions between institutions of housing markets based on nonlinear functions of costs

Objective: to study the optimal pricing strategies of firms in the “realtor - bank - insurer” system under nonlinear cost functions.Methods: game theory, supply chain coordination, multi-criteria optimization. Results: the housing market is one of the most dynamically developing segments of the economy. Pricing patterns in this market are not always subject to market laws, since they are influenced by other factors, such as the availability of loans, the presence of agents, the rates in the insurance market, etc. To analyze the pricing processes, the authors consider a vertically integrated system of interaction of agents “realtor - bank - insurer”. A system of optimality conditions for housing market agents (realtor, bank, and insurer) under nonlinear cost functions is derived, corresponding to different types of scale effects. The results of numerical experiments are presented, showing the nature of price interdependencies in these markets in cases of convexity or concavity of the agents’ cost functions.Scientific novelty: in contrast to the “realtor - bank - insurer” system with linear cost functions, our study demonstrates the following insights: first, if all agents have concave cost functions, then the housing price, mortgage interest rate, and insurance rate are lower compared to the situation in which agents have convex cost functions; second, an increase in the intra-system commission rate leads to an increase in the price of the agent who pays the commission, and a decrease in the price of the agent who receives it; third, an increase in the commission rate causes a sharper reduction in the agent’s price if the agent has a convex cost function and the counterparty has a concave one, than in the opposite case.Practical significance: the results can be applied in the elaboration of state programs for the development of the housing market, mortgage subsidies and regulation of the insurance market; in addition, on the basis of our recommendations, firms in the “realtor - bank - insurer” system can make mutually beneficial decentralized decisions

Analysis of reflective game of agents in telecommunications market for a case of two reflective agents

Objective comparative analysis of reflexive and nonreflexive strategies of market agentsrsquo behavior in accordance with Stackelberg equilibrium. Methods game theory economic and mathematical modeling. Results modeling of information equilibria of the Russian telecommunications market is carried out. In the game of three oligopolists on arbitrary ranks of strategic reflection of two of them the possible variants of equilibria are analyzed the solution of all available variants of equilibria on arbitrary ranks of reflection at linear functions of demand and expenses is received. Modeling of information equilibria of the Russian telecommunications market showed possible strategies to improve the agentsrsquo market positions. Scientific novelty the equilibrium in the market of oligopoly with three agents is considered two of which reflect and the third acts in accordance with their ideas. The reflexive behavior of the oligopoly market agents leads to a significant shift in the market equilibrium in comparison with nonreflexive behavior while the strategy of the nonreflexive agent is ineffective in all cases since its market share decreases with an increase in the reflection rank. Practical significance the obtained informational equilibria can be used for comparison with the structure of the Russian telecommunications market to determine the type of the companiesrsquo reflexive behavior

Theoretical-game analysis of the variants of the fourth operator entering the telecommunication market of Russia

Objective: to analyze the possible distribution structures of mobile communication traffic and profit in the Russian telecommunications market for the entrance of a fourth mobile operator.Methods: game theory and economic and mathematical modeling.Results: the article examines the oligopolistic market of telecommunications services, whose participants are largely affected by the appearance of a new participant in the market. The main solutions of oligopolists were considered using game theory and reflection analysis. Based on the linear model of the game of oligopolistic market agents, possible variants of equilibriums in the market game of four oligopolists with different ranks of strategic reflection were investigated. The modeling of information balances between agents in the Russian telecommunications market was carried out, which was used to determine the possible strategies for improving the market positions of mobile operators. Analytical formulas for calculating the estimated variations and equilibrium distributions of market share and profit for a market of four agents were derived, which creates additional practical value. The conclusions were made that the size of marginal costs is a decisive advantage when entering the market. It was also determined that the operators with prospective views compared to others gain advantage in the market distribution. Scientific novelty: analytical formulas for calculating the estimated variations and equilibrium distributions of market shares and profits in the game of oligopoly are derived for the case of four agents with different cost functions.Practical significance: the calculated information equilibriums can be used to make comparisons with the Russian telecommunications market structure in order to determine the type of operators’ reflexive behavior. The developed models of information equilibrium and market agents’ behavior are also applicable to other Russian markets

Ionizing radiation, higher plants, and radioprotection: From acute high doses to chronic low doses

© 2018 Caplin and Willey. Understanding the effects of ionizing radiation (IR) on plants is important for environmental protection, for agriculture and horticulture, and for space science but plants have significant biological differences to the animals from which much relevant knowledge is derived. The effects of IR on plants are understood best at acute high doses because there have been; (a) controlled experiments in the field using point sources, (b) field studies in the immediate aftermath of nuclear accidents, and (c) controlled laboratory experiments. A compilation of studies of the effects of IR on plants reveals that although there are numerous field studies of the effects of chronic low doses on plants, there are few controlled experiments that used chronic low doses. Using the Bradford-Hill criteria widely used in epidemiological studies we suggest that a new phase of chronic low-level radiation research on plants is desirable if its effects are to be properly elucidated. We emphasize the plant biological contexts that should direct such research. We review previously reported effects from the molecular to community level and, using a plant stress biology context, discuss a variety of acute high-and chronic low-dose data against Derived Consideration Reference Levels (DCRLs) used for environmental protection. We suggest that chronic low-level IR can sometimes have effects at the molecular and cytogenetic level at DCRL dose rates (and perhaps below) but that there are unlikely to be environmentally significant effects at higher levels of biological organization. We conclude that, although current data meets only some of the Bradford-Hill criteria, current DCRLs for plants are very likely to be appropriate at biological scales relevant to environmental protection (and for which they were intended) but that research designed with an appropriate biological context and with more of the Bradford-Hill criteria in mind would strengthen this assertion. We note that the effects of IR have been investigated on only a small proportion of plant species and that research with a wider range of species might improve not only the understanding of the biological effects of radiation but also that of the response of plants to environmental stress

Contribution for the derivation of a soil screening value (SSV) for uranium, using a natural reference soil

In order to regulate the management of contaminated land, many countries have been deriving soil screening values (SSV). However, the ecotoxicological data available for uranium is still insufficient and incapable to generate SSVs for European soils. In this sense, and so as to make up for this shortcoming, a battery of ecotoxicological assays focusing on soil functions and organisms, and a wide range of endpoints was carried out, using a natural soil artificially spiked with uranium. In terrestrial ecotoxicology, it is widely recognized that soils have different properties that can influence the bioavailability and the toxicity of chemicals. In this context, SSVs derived for artificial soils or for other types of natural soils, may lead to unfeasible environmental risk assessment. Hence, the use of natural regional representative soils is of great importance in the derivation of SSVs. A Portuguese natural reference soil PTRS1, from a granitic region, was thereby applied as test substrate. This study allowed the determination of NOEC, LOEC, EC20 and EC50 values for uranium. Dehydrogenase and urease enzymes displayed the lowest values (34.9 and ,134.5 mg U Kg, respectively). Eisenia andrei and Enchytraeus crypticus revealed to be more sensitive to uranium than Folsomia candida. EC50 values of 631.00, 518.65 and 851.64 mg U Kg were recorded for the three species, respectively. Concerning plants, only Lactuca sativa was affected by U at concentrations up to 1000 mg U kg1. The outcomes of the study may in part be constrained by physical and chemical characteristics of soils, hence contributing to the discrepancy between the toxicity data generated in this study and that available in the literature. Following the assessment factor method, a predicted no effect concentration (PNEC) value of 15.5 mg kg21dw was obtained for U. This PNEC value is proposed as a SSV for soils similar to the PTRS1

25 years after the accident at the Chernobyl nuclear power plant: Radioecological lessons

The area affected by the Chernobyl accident has become a unique test site where long-term ecological and biological consequences of a drastic change in a range of environmental factors as well as trends and intensity of selection are studied in natural settings. The consequences of the Chernobyl accident for biota varied from an enhanced rate of mutagenesis to damage at the ecosystem level. The severity of radiation effects was strongly dependent on the dose received in the early period after the accident. The most exposed phytocenoses and soil animals’ communities exhibited dose dependent alterations in the species composition and reduction in biological diversity. These findings make a valuable contribution to scientific and public understanding of the environmental risks of ionizing radiation and to debates on the environmental costs, benefits and risks of nuclear energy

Development of an approach to assess critical doses and dose rates for cultivated plants

The aim of this work is to develop methods for an assessment of critical doses and dose rates that can result in significant radiation-induced effects in agrocenoses. This is realized on an example of cultivated plants which are one of the main components of agroecosystems. Available information on dose dependences in such umbrella endpoints as reproduction, survival, morbidity, alterations in morphological and biochemical processes, genetic effects in crops, vegetables, fruit trees, etc are gathered from papers issued mainly in Russian scientific press during last 50 years. Data are maintained as database in MS Access that contains about 10000 records at the moment. As critical exposure values, doses are considered producing 50% changes of biological effect at acute impact (ED50), or dose rates resulting in 10% changes at chronic exposure of plants (EDR10). The critical doses and dose rates for agrocenosis estimated from available information on reproduction and survival are presented here. Primary data are assesed for their quality according to several criteria. Three models (linear, logariphmic, logistic) for dose-effect relationship are tested for an applicability to fit a dose-effect dependence taking account of their goodness-of-fit and robustness of ED50 and EDR10 estimates

Structural analysis of oligopoly market based on the reflective game model by the example of telecommunication market in Russia

Objective to analyze the possible structures of the oligopoly market distribution by the example of telecommunication industry in terms of the agentsrsquo reflexive behavior. nbsp Methods game theory economicmathematical modeling. Results the article states that one of the first objects in the game theory is an oligopoly market. Based on the analysis of game theory studies it was found that there is a need to achieve information equilibrium in reflexive games of three agents in the oligopoly market. To solve this problem we analyzed all possible representations of the agents leading to the set of games in the Russian telecommunications market for three agents OJSC ldquoMTSrdquo OJSC ldquoMegafonrdquo and OJSC ldquoVympelcomrdquo. Three reflection grades were studied 1 representations of the agent about other agents 2 representations of the agentrsquos perception of other agents about it and 3 representations of the agent about what its competitors think about the first agentrsquos opinion about the other two. As a result the general patterns were revealed of the expressions of conjectural variations in each case it was proved that further detailing of the reflection is not needed. As a result of calculations the models of informational equilibriums of the Russian telecommunication market were constructed for that the averaged values of the demand and cost functions parameters functions of cellular communication operators were taken. It was also revealed that in 2015 the actual telecommunication market in the Russian Federation qualitatively i.e. by the ratio of market shares was close to equilibrium on condition of first rank reflexive behavior for the case when the market leader OJSC ldquoMTSrdquo represents its counterparties ndash OJSC ldquoMegafonrdquo and OJSC ldquoVympelcomrdquo ndash as the driven agents. Scientific novelty the analytical expressions for the information equilibrium parameters issues and profits of the agents aggregate output and prices are obtained in the oligopoly market with a linear demand function linear cost functions of agents with equal marginal and fixed costs for arbitrary reflection grades. Practical significance the obtained set of informational equilibriums may be used to compare it to the actual equilibriums of the Russian telecommunications market to assess the reflection grades of its agents

Analysis of demand curves in the stock and financial markets of monopolistic competition

Objective to identify patterns of monopolistic competition as applied to markets of household appliances consumer loans and insurance products in Russia. Methods econometric modeling trending regression analysis analysis of statistical significance. Results the statistical analysis of trends in the market of household appliances insurance and credit markets has been carried out the statistical significance and adequacy of the models has been assessed adequate and accurate regression models of price trends of household appliances and electronics have been developed as well as of the interest rates of consumer loans and insurance rates for loan debts. Scientific novelty the actual patterns of decreasing demand curves for household appliances consumer loans and insurance products were found for the relevant markets in the Russian Federation in 2009ndash2014. Practical significance the model can be used for solving problems of optimal planning strategies of retailers insurers and banks. nbs