619 research outputs found
Innovations of the Beginning of the Sixth Millennium BC in the Northern Pontic Steppe
This study focuses on the pottery-bearing ("Neolithic") sites of the northern Azov Sea region. The vessels ornamented with comb imprints appeared there in the sixth millennium BC. In the light of a recent re-dating of the Rakushechny Yar site sequence, the sites of the northern Azov region appeared to be the earliest evidence for this innovation. The innovation in the ceramic assemblage is accompanied by an innovative lithic tool set. The latter included macro-blades and fan-shaped end-scrapers, which were previously unknown in the studied region. Their reanalysis (including new field work at the single-layer site of Chapaevka) helped formulate a hypothesis of maritime transmission of comb-ornamented ceramics in the Black and Azov Sea. This hypothesis will stimulate further discussions regarding the ways of Neolithization in Eastern Europe. It underlines the connections between Balkan "classic"Neolithic and pottery-bearing sites of the Ukrainian Steppe. The impressed ware from Makri and other mainland Greek sites is treated as the closest analogy to the finds of the northern Azov Sea region
Thermochemistry of Al-Si-Fe(Co, Ni) Ternary Melts
The thermochemical properties of Al-Co-Si liquid alloys remain unexplored. Therefore, to estimate the interaction characteristics of liquid Al-Co-Si alloys we have simulated the mixing enthalpies, using the regular approximation and applying "geometric" model by Bonnier-Caboz
Hydrothermal synthesis of zeolites from coal fly ash
The fly ash, from the combustion of coal to produce energy and heat, is an industrial waste, in which large accumulations represent a serious environmental threat. To reduce the environmental burden and improve the economic benefits of energy production, the science and industry focus on the transformation of coal combustion byproducts into new functional materials. The fly ash was studied by modern analytical methods. As a result of the hydrothermal reaction, several types of zeolites were synthesised from the fly ash: analcime, faujasite (zeolite X) and gismondine (zeolite P). It was shown that the experimental conditions (temperature, reaction time and alkali concentration) have a significant influence on the type of zeolite and its content in the reaction products. The series of experiments resulted in building approximate crystallisation field of zeolites and other phases as the first stage of the formation of ceramic membrane and other materials
Photodynamic inactivation of gramicidin channels: a flash-photolysis study
AbstractPhotosensitized inactivation of ionic channels formed by gramicidin in the planar bilayer lipid membrane (BLM) has been studied upon exposure of the BLM to single flashes of visible light in the presence of tetrasulphonated aluminium phthalocyanine. The gramicidin photoinactivation is inhibited by the addition of unsaturated phospholipids to the membrane-forming solution as well as by the addition of azide to the bathing solution, consistent with involvement of singlet oxygen. The characteristic time of the photoinactivation (T) does not change markedly under these conditions. Moreover, T remains nearly constant upon alteration of the flash energy and the photosensitizer concentration. The value of T appears to be sensitive to the gramicidin concentration and to the factors affecting the open time of the gramicidin channels, namely the temperature and the solvent used in the membrane-forming solution. The photoinactivation is not observed with covalent gramicidin dimers. The equations derived from the model of Bamberg and Laeuger (J. Membrane Biol. (1973) 11, 177–194), describing the relaxation of the gramicidin-induced conductance after a sudden distortion of the dimer-monomer equilibrium, are shown to explain consistently the time course of the photoinactivation provided that the damage of the gramicidin molecules leads to deviation from the equilibrium
Verifying the chronology of Ukrainian Neolithic
This paper addresses the earliest Neolithic phases in Ukraine: aspects relating to the chronology, methods and time of Neolithisation. In general, the earliest Neolithisation relates to the times of the Linear Pottery culture. Nevertheless, Ukraine has numerous eco-zones so the process could have been different in other zones. The authors emphasize that the key to getting closer to solving this problem is the chronology-re-dating and validation program. Hitherto dates of one culture or period of culture have been treated against each other. This article presents a small series of AMS from well-defined contexts of four sites, previously dated by the Kyiv radiocarbon facility. The results are compared with existing dates in order to establish the validity of existing chronologies for the Neolithic of Ukraine. Obtained results allowed the authors to conclude that the Kyiv dates should not be obligatorily treated as wrong. Furthermore, the authors reopened the discussion to establish what was the role of LBK and Azov-Dnieper culture communities in spreading farming and herding in Ukraine during the second half of the VIth millennium BC
Investment development of Russian regions backed up by natural monopolies
The article considers the issues of the relationship between business investment activities and the economic and social development of the regions.
Based on the statistical data analysis it is shown that the decrease in investment activities negatively affects all key indicators of regional development after a short period of time.
The article shows that a peculiarity defining Russian economy is that its significant part is actually controlled by natural monopolies. At the same time, they are strongly sensitive to all the problems of socioeconomic development of the country's territories and, therefore, are parties concerned in ensuring sustainable and qualitative growth of regional economies.
Today many of the natural monopolies implement large-scale investment programs with allocated substantial resources. The analysis of these investment programs showed that they all contain components that contribute to the development of the region where the manufacturing facilities or transportation capacities of these companies are located.
It is concluded that a systemic state investment policy aimed at stimulating real investments, rather than "portfolio" ones, is required to address the problem of sustainable economic growth.peer-reviewe
Capital accounting and liabilities problems in the context of economic processes reforming and international financial reporting standards introducing
Reform in the Russian Federation raises a number of problems, including the regulation of capital and liabilities accounting. The object of the study is the International Financial Reporting Standards impact on the domestic accounting system development, reflecting the economic processes globalisation and digitalisation, the emergence of new accounting objects and increasing requirements for the reporting quality. The essence of newly emerging accounting categories was analysed in the article, the definitions of “liabilities” in the International Financial Reporting Standards and domestic practice were compared. It was identified, that gaps in the capital and liability accounting caused by the lack of a unified conceptual apparatus, the presence of estimated values, the use of an accountant professional judgment that affects the information quality in reporting, the backlog of legislative regulation in terms of accounting for digital objects as authorized capital. The accounting and reporting issues in the reporting of operations of the business social orientation were considered. Possible ways of solving the liability accounting problems are presented, including the conceptual apparatus unification, the accounts chart modernisation, the development of recommendations regarding the application of the accountant professional judgment, the expansion of requirements for the information list on the economic entity activities presented in the accounting (financial) statements, and the International Financial Reporting Standards application
The interaction of phthalocyanine with planar lipid bilayers Photodynamic inactivation of gramicidin channels
AbstractThe effect of phthalocyanines, the potent photodynamic sensitizers, on the electric properties of the bilayer lipid membrane (BLM) is studied. It is shown, that tetrasulfonated, as well as trisulfonated, aluminium phthalocyanine do not alter the conductance of BLM, but elicit certain changes in the boundary potential difference, which points in favor of dye adsorption on BLM. Under the conditions of intense visible light irradiation, the phthalocyanines cause an increase in the conductance, resulting in the irreversible breakdown of BLM, formed from soy bean phosphati-dylcholine, but fail to change the conductance of BLM, formed from diphytanoilphosphatidylcholine. The phthalocyanine-sensitized inactivation of gramicidin channels incorporated into BLM is observed under the conditions of weak visible light irradiation using an He-Ne laser. The photodynamic blockage of model ionic channels is considerably suppressed after oxygen depletion. The phenomenon consists of a marked reduction of a number of open channels, probably due to photomodification of tryptophan residues, essential for gramicidin functioning. The mechanism of the channel inactivation, involving the photosensitized reaction of the II type, and the relevance to the interaction of sensitizers with biomembranes, is discussed
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