Soil-derived branched glycerol dialkyl glycerol tetraethers (brGDGTs) in marine river fan sediments have a potential use for determining changes in the mean annual temperature (MAT) and pH of the ...river watershed soils. Prior to their incorporation in marine sediments, the compounds are transported to the marine system by rivers. However, emerging evidence suggests that the brGDGTs in freshwater systems can be derived from both soil run-off and in situ production. The production of brGDGTs in the river system can complicate the interpretation of the brGDGT signal delivered to the marine system. Therefore, we studied the distribution of brGDGT lipids in suspended particulate matter (SPM) of the Yenisei River. Chromatographic improvements allowed quantification of the recently described hexamethylated brGDGT isomer, characterized by having two methyl groups at the 6/6′ instead of the 5/5′ positions, in an environmental dataset for the first time. This novel compound was the most abundant brGDGT in SPM from the Yenisei. Its fractional abundance correlated well with that of the 6-methyl isomer of the hexamethylated brGDGT that contains one cyclopentane moiety. The Yenisei River watershed is characterized by large differences in MAT (>11°C) as it spans a large latitudinal range (46–73°N), which would be expected to be reflected in brGDGT distributions of its soils. However, the brGDGT distributions in its SPM show little variation. Furthermore, the reconstructed pH values are high compared to the watershed soil pH. We, therefore, hypothesize that the brGDGTs in the Yenisei River SPM are predominantly produced in situ and not primarily derived from erosion of soil. This accounts for the absence of a change in the temperature signal, as the river water temperature is more stable. Using a lake calibration, the reconstructed temperature values agree with the mean summer temperatures (MST) recorded. The brGDGTs delivered to the sea by the Yenisei River during this season are thus not soil-derived, possibly complicating the use of brGDGTs in marine sediments for palaeoclimate reconstructions.
The distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in soils has been shown to correlate with pH and mean annual air temperature. Because of this dependence brGDGTs have ...found an application as palaeoclimate proxies in coastal marine sediments, based on the assumption that their distribution is not altered during the transport from soils to marine systems by rivers. To study the processes acting on the brGDGT distributions, we analysed the full suite of brGDGTs, including the recently described 6-Me brGDGTs, in both the suspended particulate matter (SPM) of the Siberian Yenisei River and the SPM and sediments of its outflow in the Kara Sea. The brGDGT distribution in the SPM of the Yenisei River was fairly constant and characterized by high abundances of the 6-Me brGDGTs, reflecting their production at the neutral pH of the river water. However, the brGDGT distribution showed marked shifts in the marine system. Firstly, in the Yenisei River Mouth, the fractional abundance of the 6-Me brGDGTs decreases sharply. The brGDGT signature in the Yenisei River Mouth possibly reflects brGDGTs delivered during the spring floods that may carry a different distribution. Also, coastal cliffs were shown to contain brGDGTs and to influence especially those sites without major river inputs (e.g. Khalmyer Bay). Further removed from the river mouth, in-situ production of brGDGTs in the marine system influences the distribution. However, also the fractional abundance of the tetramethylated brGDGT Ia increases, resulting in a distribution that is distinct from in-situ produced signals at similar latitudes (Svalbard). We suggest that this shift may be caused by preferential degradation of labile (riverine in-situ produced) brGDGTs and the subsequent enrichment in less labile (soil) material. The offshore distribution indeed agrees with the brGDGT distribution encountered in a lowland peat. This implies that the offshore Kara Sea sediments possibly carry a soil-dominated signal, indicating potential for palaeoclimate reconstructions at this site.
Both in the river system and coastal cliffs, brGDGTs were much more abundant than crenarchaeol, an archaeal isoprenoid GDGT, resulting in high (>0.93) Branched and Isoprenoid Tetraether (BIT) index values. Moving downstream in the marine sediments, a decrease in brGDGT concentrations, coeval with an increase in crenarchaeol, resulted in decreasing BIT index values. This decrease correlates with changes in bulk proxies for terrigenous input (δ13Corg, C/N), confirming the use of the BIT index to trace the delivery of river-transported and coastal cliff-derived terrigenous organic matter.
In this article, Nikolai Polevoy’s play Parasha Sibiryachka (1840) is analyzed as an instrument of influence on Emperor Nicholas I. The plot of the play in this perspective can be understood as a ...direct appeal to the authorities to grant mercy and change the fate of the disgraced writer. Polevoy encodes an anecdote from the early history of Alexander the First’s reign into the signs of Nicholas the First’s «scenario of power», expecting that each of these signs will be correctly read in the Emperor’s box. However, Polevoy’s plan did not come to fruition, and Parasha Sibiryachka did not lead to any radical changes in the life of its author, despite its theatrical success and attention from the tsar. The cause of this, as explained in the article, was crisis of the paternalistic model of the theater economy, in which a high patron remained the only source of capitalization for the author’s work. The case of Parasha Sibiryachka simultaneously shows that new (probably, market) mechanisms of the theater economy, which were theoretically described by Polevoy himself, had not yet taken shape in Russia by the beginning of the 1840s. The article proposes Leib-kucher Petra III, an 1800 play by A. von Kotzebue, together with the incredible biographical anecdote associated with it, as both an inspiration for Polevoy’s strategy and the source of his play. The German playwright was sent to Siberia and then returned to Petersburg and showered with favors for his play, which somewhat resembles Parasha Sibiryachka on the levels of composition and plot. The failure of Polevoy’s attempt to play the “Kotzebue scenario” is described in the article as a symptom of the changed economic relations in the Russian theater. DOI: 10.31168/2305-6754.2019.8.2.9
Nowadays material science involves powerful 3D imaging techniques such as X-ray computed tomography that generates high-resolution images of different structures. These methods are widely used to ...reveal information about the internal structure of geological cores; therefore, there is a need to develop modern approaches for quantitative analysis of the obtained images, their comparison, and classification. Topological persistence is a useful technique for characterizing the internal structure of 3D images. We show how persistent data analysis provides a useful tool for the classification of porous media structure from 3D images of hydrocarbon reservoirs obtained using computed tomography. We propose a methodology of 3D structure classification based on geometry-topology analysis via persistent homology.
Eutrophication is a major ecological problem and affects and endangers freshwater bodies, making assessment of the trophic status of water bodies crucial for their restoration and sustainable use. ...Lake Baikal is affected by a number of environmental stressors, including coastal eutrophication. Daily measurements of concentrations of nutrients, dissolved oxygen (DO), chlorophyll-a (Chl-a), weekly measurements of algae abundance and biomass in the open water season in June-December 2020, and measurements of concentrations of nutrients at 2–7-day intervals in June-October 2021 were made in the littoral of the South Baikal for the first time. It was shown that nitrate and phosphate concentrations decreased by July-August, their minimum content was maintained until September, concentrations began to increase in October and reached a maximum in December. The maximum abundance and biomass of algae and chlorophyll concentrations were only observed in early July. Storm situations increased the content of nitrogen, phosphorus and DO in water, the duration of their influence was not more than 2 days. A correlation matrix revealed significant positive correlations of NO3−-DO, phosphate (SPR)-NO3−, SRP-DO and biomass-Chl-a and strong negative correlations between water temperature (Tw)-DO, Tw-NO3−, Tw-total nitrogen (TN) and Tw-SRP. Based on SRP and NO3− concentrations and TN:TP ratios, it was concluded that algal development was limited to nitrogen and phosphorus in summer. The trophic status of the Southern Baikal littoral zone was assessed using classifications based on TN, TP, NO3−, SRP, Chl-a content and algal biomass, as well as the Carlson index (TSI) and probabilistic assessment. The results of assessments using different methods of trophic status determination showed that the Baikal littoral zone in the study area belongs to the oligotrophic type with minor elements of mesotrophy. According to the saprobity index, water purity of littoral waters varies within the oligosaprobic and β-mesosaprobic zones and corresponded to quality classes II and III (clean and moderate purity); the system demonstrates a high capacity for self-purification.
•Changing distribution of 15 brGDGTs in the outflow of Selenga River into Lake Baikal.•Linear mixing and in situ production or degradation of brGDGTs occurs in the outflow.•The lake brGDGT signal is ...produced in situ, or is a mix from high- and lowland rivers.•The lake brGDGT signal exported is distinct from the downstream Yenisei River.
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids found in several environments, including soils, rivers and lakes, whose distribution varies with temperature and pH, although this dependence is apparently not the same for the different environments. Mixing of brGDGT sources may thus complicate palaeoenvironmental reconstruction. The extent to which brGDGTs in a lake outflow reflect the distribution delivered by upstream rivers was studied for Lake Baikal (Russia), one of the largest freshwater lakes worldwide. Fifteen brGDGTs in suspended particulate matter (SPM) of the Selenga River and its outflow from the lake were quantified. The river and lake SPM had rather different distributions. The riverine distribution was still apparent in the SPM of the lake surface water 5km from the river mouth, but shifts in the distribution were already apparent in the SPM of the surface water after 1km. Based on the brGDGT distributions of the SPM of the Selenga outflow and that of the lake, conservative mixing between the river and the lake brGDGT distributions could not fully explain the observed shifts in distributions. Both preferential degradation and in situ production of brGDGTs in the surface and, especially, bottom water of the river outflow were potentially responsible. This implies that a riverine lipid distribution delivered to a lake can be modified prior to being transported downstream. The lacustrine brGDGT distribution, that possibly could have reflected a mixture of mountainous and Selenga River SPM, was not recognized in downstream Yenisei River SPM. The watershed of Lake Baikal thus does not seem to contribute to the brGDGTs transported to the marine system. As many large rivers have major lakes in their watershed, this has implications for palaeoclimate reconstruction from river fan sediments globally.
This study revises the δ18O and δ2H status of Lake Baikal. The mean values of δ18O and δ2H varied from −15.9 to −15.5‰ and from −123.2 to 122.2‰, respectively, for the past 30 yr. The isotopic ...composition of the lake remained more ‘‘light” compared to the regional precipitation and rivers inflows. The isotopic composition of the lake has begun to change since ca.1920 after the Little Ice Age; however, Lake Baikal still has not reached the isotopically steady state in the present. The calculated composition of the steady-state should be −12.3‰ for δ18O and −103.6‰ for δ2H. If regional climate parameters do not change dramatically, Lake Baikal will reach these values in ca. 226 yr. Based on isotopic fingerprints of the upper (0 to 150 m) and near-bottom layers (ca. 150 m from the bottom floor), the renewal in the southern and central basins of Lake Baikal has occurred recently compared to the northern Baikal basin, and the size of the mixing-cell of downwelling is close to 30 km.
Forest fires lead to the serious damage of ecological state and national economy of the country. This problem is especially relevant for Siberians. According to Greenpeace, Siberian forest fires in ...2019 reached record levels in the entire history of observation in terms of burning area and the amount of carbon dioxide emitted into the atmosphere. It leads not only to a deterioration in the health of Siberians, but also to environmental problems of the region. Note that the large-scale fire-prevention measures entails enormous financial costs. Therefore, economical, ecological and mathematical modeling of the situations, arose in forest fires countering, becomes actual. The paper is devoted to optimal control problem of forest fires fighting. Its prototype is the well-known Parks model. To investigate the model, we apply the modern programming language Julia, which is designed to mathematical calculations and numerical studies. We made an extensive computational experiment in this model and a numerical analysis of corresponding optimal control problems. The obtained results were examined both on the adequacy of the model, and on the possibility of using the Julia language and the included solvers of mathematical problems.
Chain retailing is one of the most actively developing sectors of the Russian economy. Moreover, its condition has long been at a sufficiently high level of development to consider in detail the ...technology of an integrated, systematic arrangement of marketing analysis work. Modern practice shows that traditional retailers operating in classic trading formats do not pay enough attention to progressive marketing tools. According to the leaders of the grocery chain retailing, marketing efforts in this segment of the retail market are ineffective. In addition, current events related to the pandemic are making their own adjustments to the development of retail in the food market. It is this segment of the chain business that suffered the greatest losses. The article deals with the analysis of the state of the grocery retailing in the pandemic and post-pandemic periods. Marketing actions and tools used by representatives of the chain retailing, as well as its arrangement in the context of new trade formats are analyzed. The possibility of applying a new strategy of interaction between grocery retail representatives and suppliers, manufacturers is considered. Marketing ways of increasing the efficiency of retail chains in the grocery market are suggested.
This article analyzes two of the main aspects of Nikolay Nekrasov's poem for children, “Grandpa Mazai and the Hares” (1871)–the pedagogical and the ecological. The article demonstrates that this ...story about the rescue of hares during the spring flood, which is a standard selection in poetry readers in Russia, was intended as a graphic illustration of the “economic perspective” from which social elites viewed the Russian peasantry. But the story was so vivid and unusual that the economic aspect overshadowed the ecological issues. This article shows that this poem, addressed to children, was the first ecological text in Russian literature to posit a new type of attitude toward wild animals. Nekrasov's ecological model took shape in dialogue with a variety of discourses extant at the time–about education, biology, and hunting. The poet's work was elevated into the literary canon as an example of lyrics about “love for one's little brothers.” But its message was greatly simplified over time, as other writers who aimed their work solely at children adopted it and gradually transformed “Grandpa Mazai” into just one of many texts that advocated for the humane treatment of animals.
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