Akbari M.,Kazan Federal University |
Andrianov S.N.,Tatarstan Academy of science |
Kalachev A.A.,Kazan Federal University
Laser Physics | Year: 2017
The frequency conversion of light has proved to be an important instrument for communication, spectroscopy, imaging and information processing. We theoretically study the frequency conversion of a single photon via its interaction with a λ-type atom coupled to a microdisk. We show that the frequency conversion efficiency approaches unity even in the case of an interaction between clockwise and counterclockwise modes in the microdisk due to surface imperfections. By the use of the Schrieffer-Wolff transformation, we get an effective Hamiltonian that allows us to investigate the dynamics of the system and obtain time and probability of frequency conversion in different conditions.
Askeyev A.,Tatarstan Academy of science |
Askeyev O.,Tatarstan Academy of science |
Yanybaev N.,Bashkir State Nature Reserve |
Askeyev I.,Tatarstan Academy of science |
And 3 more authors.
Environmental Biology of Fishes | Year: 2017
Studies on assemblages of freshwater fishes along elevational gradients of rivers are lacking, even in Europe. In this paper we have explored the entire range of elevational gradients existing in the European part of Russia. We analyzed how fish biodiversity (species richness, abundance, diversity indices) at 435 river sites differed by elevation. The impact of elevation on the distribution of freshwater fish species was analyzed using regression and ordination methods. For the first time for a large area of Eastern Europe, optimum points and niche breadth for fish species along altitude gradients were estimated. Our analyses showed: (1) species richness and Shannon index decreased in the upper part of the gradient; fish abundance showed a unimodal response to elevation; highest numbers were found at elevations between 250 and 500 m; (2) ordination analysis demonstrated an upstream-downstream gradient of the fish assemblages; (3) regression analysis showed significant preferences for elevation by 19 species, all of which were monotonic; (4) optimum and niche breadth (tolerance) were highly variable between species; only five species (brown trout, grayling, common minnow, bullhead and stone loach) were encountered at elevations above 650 m; and (5) in our region, the habitat of grayling was higher in the mountains, and its abundance (numbers) at extreme elevations was greater, than brown trout. These results show how fish assemblages differ with elevation. Our findings identify the data that can be used for regional environmental monitoring of the state of small rivers and for aquatic conservation. © 2017 Springer Science+Business Media Dordrecht
PubMed | University of Tübingen, Tatarstan Academy of science, Museu de Historia de Barcelona, State Office for Cultural Heritage Management Baden Wurttemberg and 4 more.
Type: Journal Article | Journal: Cell host & microbe | Year: 2016
Ancient DNA analysis has revealed an involvement ofthe bacterial pathogen Yersinia pestis in several historical pandemics, including the second plague pandemic (Europe, mid-14(th) century Black Death until the mid-18(th) century AD). Here we present reconstructed Y.pestis genomes from plague victims of the Black Death and two subsequent historical outbreaks spanning Europe and its vicinity, namely Barcelona, Spain (1300-1420 cal AD), Bolgar City, Russia (1362-1400 AD), and Ellwangen, Germany (1485-1627 cal AD). Our results provide support for (1) a single entry of Y.pestis in Europe during the Black Death, (2) a wave of plague that traveled toward Asia to later become the source population for contemporary worldwide epidemics, and (3) the presence of an historical European plague focus involved in post-Black Death outbreaks that is now likely extinct.
Krinari G.A.,Kazan Federal University |
Khramchenkov M.G.,Kazan Federal University |
Rakhmatulina Y.,Tatarstan Academy of science
Russian Geology and Geophysics | Year: 2014
A difference-spectrum method is proposed for the qualitative assessment of changes of illite-smectite structures accompanying the flooding of oil reservoirs. The method permits one to get an open system and reduce the application of procedures based on Markov's chain formalism. A computer simulation is made to obtain spectra by subtracting the spectrum of an ethylene glycol-saturated sample from the spectrum of an air-dried preparation throughout the entire range of concentrations of illite and smectite components with a short-range order factor R = 0 or R = 3.It has been established that only in the presence of filtration are the maximum and minimum of the spectra in the range of 12.5-9.4 A complicated by a number of local extrema, whose position is specified by the structure of intermediate phases. The flooding process first involves mixed-layer phases with R = 0, leading to a partial segregation of the structures into phase with one and two networks of interlayer H2O. When the secondary mica particles break, phases with R = 3 appear along the boundaries of nanoblocks, first only with 1 H2O and then only with 2 H2O in labile interspaces. Their coexistence with the phases R = 0 in the sample proves the existence of percolation effects due to two-phase filtration in the porous medium. The fully flooded reservoir is always dominated by a mechanical mixture of illite-smectite phases of different nature with R = 0 and with different ratios of components. Transformation of mica that can drastically reduce oil production begins long before the appearance of flooding zones, which are revealed by standard logging methods. © 2014 .
Askeyev O.V.,Tatarstan Academy of science |
Sparks T.H.,University of Life Sciences in Poznań |
Askeyev I.V.,Tatarstan Academy of science |
Tishin D.V.,Kazan Federal University |
Tryjanowski P.,University of Life Sciences in Poznań
Global Ecology and Biogeography | Year: 2010
Aim To examine whether change in the timing of a large number of phenological events and their response to temperature differs between trophic levels during the period 1988-2008.Location In the vicinity of Kazan, Tatarstan Republic, Russia (55°45' N, 49°08' E).Methods Observations of the dates of first events of 22 plant phases, 8 insect phases, 3 herpetofauna phases and 26 migrant bird phases were examined using regression to assess changes over time and response to temperature. Differences between trophic levels were assessed using ANOVA.Results In comparison to studies from western Europe, relatively few phenological series (15) revealed a significant advance over time, but a much larger number (37), including all the herpetofauna and nearly all the plants, showed a response to temperature. Trends in birds were, on average, twice as great as those for plants, but plants had a significantly greater temperature response. Over the study period local temperatures had not risen significantly but some phenological change was still evident.Main conclusions Phenological change has been less marked in the eastern edge of Europe than in western and central Europe. This is compatible with a lack of significant local warming during the study period. A large number of species show strong responses to temperature so will be expected to advance if/when local temperatures do increase. In contrast to results from elsewhere in Europe, early events were not the most temperature responsive, suggesting local adaptation preventing precocious behaviour and the consequent dangers of sub-zero temperatures. © 2010 Blackwell Publishing Ltd.
Valeev R.M.,Kazan Federal University |
Khabibullin M.Z.,Tatarstan Academy of science |
Saidasheva E.A.,Kazan Federal University |
Nurgalieva L.A.,Kazan Federal University
Journal of Sustainable Development | Year: 2015
The urgency of the problem under investigation is caused by the increased interest of modern researchers in the problems of interethnic and interconfessional interaction. The aim of the research consists in the objective representation of history of the missionary departments of the Kazan Theological Academy, the study of the educational, scientific and public work of its teachers and graduates, the analysis of scientific works on history, ethnography, language and culture of the Turkic, Finno-Ugrian and Mongolian peoples of the Middle Volga region in Kazan in the second half of the XIX - the beginning of the XX centuries. The Kazan Theological Academy was one of the largest religious and educational, missionary, ethnic and political institutions in Russia and, at the same time, one of the leading centers for studying history, culture, ethnography and language of the Turkic, Finno-Ugrian and Mongolian people in the second half of the XIX - the beginning of the XX centuries. The article deals with the scientific and educational activity of the only missionary departments of the Kazan Theological Academy in Russia (1842 - 1921), the contribution of such great teachers as N.I. Ilminsky, G.S. Sablukov, E.A. Malov, V.T. Timofeev, N.P. Ostroumov, M.A. Mashnov to the process of studying history, ethnography, language and culture of the peoples of the Middle Volga in Kazan in the second half of XIX - the beginning of XX centuries and to the covering of Islam and Christianity problems. The teachers of the Kazan Theological Academy made a great contribution to the historical, confessional, ethnic and political study of the Turkic, Finno-Ugrian and Mongolian people of Russia, and, moreover, they helped to preserve and develop the languages, form national education and promote integration of the people into a single cultural, educational and informational space of the Russian state. The professors of the missionary departments revealed and collected a huge amount of various materials (historical, linguistic and ethnographic) about the Tatars, the Maris, the Chuvashes, the Udmurts and the Mordvas, which are of great importance for the research of the sources of the modern international and interconfessional relations in the Republic of Tatarstan and the Russian Federation. The article can be useful for all people who are interested in the modern ethnic and political processes in the Russia Federation. © 2015 by the authors.
Askeyev O.,Tatarstan Academy of science |
Askeyev I.,Tatarstan Academy of science |
Askeyev A.,Tatarstan Academy of science |
Monakhov S.,Tatarstan Academy of science |
Yanybaev N.,Bashkir State Nature Reserve
Environmental Biology of Fishes | Year: 2015
Fish assemblages and environmental variables were studied in 245 sites in small and mid-sized rivers of the Tatarstan Republic. The basic aim of this investigation was to model the habitat requirements of the 26 most common freshwater fish species at the eastern edge of Europe since the spatial variation of the assemblages of these fish species is little understood there. The impact of environmental factors on species distribution using both presence-absence and abundance data was analyzed with regression methods and ordination methods, which are widely used by European ichthyologists elsewhere. Ordination analysis demonstrated an upstream-downstream gradient of the fish assemblages. Regression analysis indicated that basic predictors of species preference were elevation and “size” of river. For the first time in Eastern Europe, optimum points and niche breadth for fish species along basic environmental gradients were estimated. Niche breadth (tolerance) was highly variable between species. Generally, estimated relationships between environmental factors and the probability of fish presence and abundance were consistent with known fish ecology. © Springer Science+Business Media Dordrecht 2014.
Khusainov A.,Kazan Federal University |
Suleymanov D.,Tatarstan Academy of science
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013
This paper describes a speech identification system for the Tatar, English and Russian languages. It also presents a newly created Tatar speech corpus, which is used for building a language model. The main idea is to investigate the potential of basic phonotactic approaches (i.e. PRLM-approach) when working with the Tatar language. The results indicate that the proposed system can be successfully employed for identifying the Tatar, English and Russian languages. © 2013 Springer International Publishing.
Ivanov V.,Kazan Federal University |
Ivanov V.,National University of Science and Technology "MISIS" |
Ivanov V.,Tatarstan Academy of science
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014
We propose a method that facilitates a process of semiautomatic FrameNet construction. The method requires Google Books NGram dataset and WordNet or another thesaurus for a particular language. We evaluated the method for Russian ngrams. Due to a huge amount of available data the method does not require sophisticated natural language processing techniques (e.g. for word sense disambiguation), and it shows a promising result. © Springer International Publishing Switzerland 2014.
Vershinin A.A.,Tatarstan Academy of science |
Ignat'ev Y.A.,Tatarstan Academy of science
Eurasian Soil Science | Year: 2011
The characteristics of the respiration activity of leached chernozems under different land uses were studied. The use of soil-conservation technologies of crop cultivation led to an increase in the basal and substrate-induced respiration and in the content of the carbon of the microbial biomass. With respect to the microbial activity and the sustainability of the microbial pool, the soils were arranged into the following order: virgin soils → soils treated with soil-conservation technologies → soils treated with traditional methods. © 2011 Pleiades Publishing, Ltd.