162 research outputs found
Provenance of clay minerals in the sediments from the pliocene productive series, western south caspian basin
The research work presents clay mineral composition in the sediment of the Pliocene Productive Series from western South Caspian Basin and identify potential source areas for the different research regions. The Productive Series is a main reservoir unit in the South Caspian Basin and divided into a lower division and an upper division. The clay mineral assemblages document coinciding changes in provenance. At the time of the deposition of the Lower Division, the Russian Platform was a potential source area for the Absheron Peninsula and drained by Palaeo-Volga River. However, at the time deposition of the Upper Division three different sediment source could be identified for the three research areas: Absheron Peninsula – the Russian Platform was drained by the Palaeo-Volga; South Absheron Offshore Zone – the Greater Caucasus was drained by the Palaeo Samur River; Baku Archipelago – the Lesser Caucasus was drained by the Palaeo-Kura River
Inverse System in The Category of Intuitionistic Fuzzy Soft Modules
This paper begins with the basic concepts of soft module. Later, we introduce inverse system in the category of intutionistic fuzzy soft modules and prove that its limit exists in this category. Generally, limit of inverse system of exact sequences of intutionistic fuzzy soft modules is not exact. Then we define the notion which is first derived functor of the inverse limit functor. Finally, using methods of homology algebra, we prove that the inverse system limit of exact sequence of intutionistic fuzzy soft modules is exact
Palaeo-environmental evolution of Central Asia during the Cenozoic: new insights from the continental sedimentary archive of the Valley of Lakes (Mongolia)
The Valley of Lakes basin (Mongolia) contains a unique continental sedimentary archive, suitable for constraining the influence of tectonics and climate change on the aridification of Central Asia in the Cenozoic. We identify the sedimentary provenance, the (post)depositional environment and the palaeo-climate based on sedimentological, petrographical, mineralogical, and (isotope) geochemical signatures recorded in authigenic and detrital silicates as well as soil carbonates in a sedimentary succession spanning from ~34 to 21 Ma. The depositional setting was characterized by an ephemeral braided river system draining prograding alluvial fans, with episodes of lake, playa or open-steppe sedimentation. Metamorphics from the northern adjacent Neoarchean to late Proterozoic hinterlands provided a continuous influx of silicate detritus to the basin, as indicated by K-Ar ages of detrital muscovite (~798-728 Ma) and discrimination function analysis. The authigenic clay fraction is dominated by illite-smectite and “hairy” illite (K-Ar ages of ~34-25 Ma), which formed during coupled petrogenesis and precipitation from hydrothermal fluids originating from major basalt flow events (~32-29 and ~29-25 Ma). Changes in hydroclimate are recorded in [delta]18O and [delta]13C profiles of soil carbonates and in silicate mineral weathering patterns, indicating that comparatively humid to semi-arid conditions prevailed in the late(st) Eocene, changing into arid conditions in the Oligocene and back to humid to semi-arid conditions in the early Miocene. Aridification steps are indicated at ~34-33, ~31, ~28 and ~23 Ma and coincide with some episodes of high-latitude ice-sheet expansion inferred from marine deep-sea sedimentary records. This suggests that long-term variations in the ocean-atmosphere circulation patterns due to pCO2 fall, reconfiguration of ocean gateways and ice-sheet expansion in Antarctica could have impacted the hydroclimate and weathering regime in the basin. We conclude that the aridification in Central Asia was triggered by reduced moisture influx by westerly winds driven by Cenozoic climate forcing and the exhumation of the Tian Shan and Altai Mountains and modulated by global climate events
The origin, conditions and mechanism for the formation of alpine-type hyperbasites of the Lesser Caucasus
The problem of hyperbasites origin is one of the widely discussed topics in geology. This is because they often appear when no expected. Their development does not correspond to the general regularities of the geological complexes’ development. Therefore, when problematic instances of hyperbasites appear, discussion is inevitable. This is due to the imperfections of existing concepts, which are not without flaws. The essence of this concept lies in the fact that during the rotation of the Earth around its axis, geodynamic forces are formed. The hyperbasites complex by its nature belongs to deep igneous formations formed at the initial stage of development of volcano-plutonic processes, where the composition of magmatic products was not subject to decomposition. In general, the origin of igneous rocks is associated with deep anomalous processes, which were formed under the influence of geodynamic forces, where decompression of mantle matter occurs, causing a catastrophic increase in the volume of mantle matter, as well as the associated development of volcanoplutonic processes. Hyperbasites are formed both in divergent and convergent zones of the Earth’s crust. The main factor for their formation is high pressure – deep thermodynamic conditions, where there are no favorable thermodynamic conditions for the complete separation of magmatic melts by composition. The emergence of hypermafic rocks on the surface is associated with geotectonic or denudation processes. Denudation processes can expose only those hypermafic formations that are located at the site of formation. These zones include ancient platforms, sheets, terranes, etc., which were cut by deep erosion processes. As for those hyperbasic formations that are classified as alpinotype hyperbasites, they were moved to the structure of the Alps-Himalayan folded zone from the basement with a collision with subsequent geotectonic processes, where they formed in the bed of the Paleotethys Ocean, both in the process of divergence and convergence. The noted pattern of formation and the mechanism of formation of alpine-type hyperbasites clearly corresponds to the patterns of development of geodynamic forces in the face of the Earth, also with natural laws, which are the main factors in the evolution of the Earth’s crust. From the standpoint of KDEZK, the origin, mechanism of formation, as well as the form of distribution of alpinotype hypermafic rocks of the Lesser Caucasus occurred in the Paleotethys bed, under different thermodynamic conditions and at depths. Further, as a result of the collision, it participated in the formation of folded zones of the Lesser Caucasus. Within the Lesser Caucasus, two genetic types of hypermafic rocks are exposed. Some of them correspond to the convergent zone of the Tethys paleocean, while others correspond to divergent zones. In terms of ore content, the most promising are those hypermafic rocks that are genetically related to convergent zones
Inheritance of cleistogamy in interspecific hybridization of Gossypium barbadense L.
Studies of the inheritance and and variability of chasmo- and cleistogamous types of cotton flower on the base of intraspecies hybridization of Gossypium barbadense L. are an urgent genetical task, whose applications involve plant breeding and seed industry. The purpose of our study was to determine the genetic control of this trait on the base of the regularity of alternative chasmo- and cleistogamous types of flowers in intraspecific hybrids of G. barbadense species. It is of theoretical and practical significance in the development of isogenic forms, lines, and varieties with the fully closed cleistogamous type of flowers, possessing important commercial traits. A pioneering method was elaborated for determining the genetic control of chasmo- and cleistogamous types of flowers in inrtaspecific hybridization of Gossypium barbadense L., which was a continuation of our studies on interspecific cotton hybridization. Two strategies were applied to the genetic analysis of hybrids: (1) paired reciprocal hybrids F1, F2 and (2) backcrossed hybrids Fb. On the grounds of these strategies, we determined the inheritance mode of flower types in reciprocal hybrids F1, which possessed the c1cg1Cg2cg2 genotype with chasmogamous flowers without reciprocal difference. The classes segregated in F2 as follows: 1 (cg1cg1Cg2Cg2) : 2 (cg1cg1Cg2cg2) : 1 (cg1cg1cg2cg2), where cleistogamy was double recessive (This trait shows the complete dominance inheritance pattern.) Segregation into two phenotypic classes occurs in the 3:1 ratio, i.e., three plants with chasmogamous flowers per one cleistogamous. The segregation Fb is 1:1; i.e., 1 chasmogamous : 1 cleistogamous. Thus, cotton chasmogamy is inherited in F2 according to the Mendelian law in a completely dominant manner: 3:1, which is proven by the Fb cross
Эпидемиология коронарных аномалий отхождения и разветвления и их клиническая значимость
Purpose. Until the mid-20th century they could be discovered only during autopsy, it means after death. With the introduction of coronary angiography it become possible to find them in a living person. Later on, new modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) enhanced futher our abilities. It is very important to discover coronary anomalies in a living person, because some of them could lead to sudden cardiac death (SCD). In fact, coronary artery anomalies are the second main cause of the SCD in young athletes. Another importance is driven by the fact, that some of them could lead to lifethreatening complications during cardiac surgery when unknown before the operation.Methods. We prospectively reviewed all coronary angiography films from 2011 to 2016 in our center. Coronary anomalies were reviewed and classified by two independent experienced operators. Patients with congenital heart disease and coronary fistulas were excluded.Results. Out of 5055 patients 148 (2.9%) had coronary artery anomalies of origin and distribution. Those were 120 men (81.1%) and 28 women (18.9%) with an age range between 29 to 88 years. The three most common anomalies were myocardial bridge (48.7%), separate origin of the conus branch (13.5%) and separate origin of the LAD and LCX (8.1%).Conclusion. In our study we found more or less the same types and incidence rates of coronary artery anomalies as in the world literature. We had apparently higher rates of myocardial bridges, compared to average number on angiography studies, but very close to authopsy study rates.Цель исследования. До середины XX века аномалии обнаруживались только во время аутопсии, т.е. после смерти больного. Диагностика аномалий у живого человека стала возможной благодаря коронарной ангиографии. Позже КТ и МРТ совершенствовали эти возможности. Очень важно диагностировать аномалии коронарных сосудов у живого человека, так как некоторые из них могут спровоцировать внезапную сердечную смерть. У молодых атлетов аномалии коронарных сосудов – вторая основная причина, приводящая к внезапной сердечной смерти. С другой стороны, проблема актуальна и для кардиохирургии, так как дооперационная диагностика некоторых аномалий коронарных артерий может предотвратить нежелательные угрожающие жизни осложнения во время кардиохирургических операций.Материал и методы. Мы проспективно просмотрели все ангиографические фильмы нашего центра с 2011 по 2016 г. Коронарные аномалии были выявлены и классифицированы двумя независимыми опытными специалистами. Пациенты с врожденными аномалиями сердца и с коронарными фистулами были исключены из исследования.Результаты. Из 5055 обследованных пациентов 148 (2,9%) имели аномалии отхождения и разветвления коронарных артерий. Из них было 120 (81,1%) мужчин и 28 (18,9%) женщин в возрасте от 29 до 88 лет. Тремя самыми распространенными аномалиями оказались мышечные мостики (48,7%), отдельное отхождение конусной ветви (13,5%) и отдельное отхождение передней межжелудочковой ветви и огибающей ветви (8,1%).Заключение. В нашем исследовании мы нашли более или менее те же виды и частоту встречаемости коронарных аномалий, как и в мировой литерате. Но в то же время мы получили более высокий уровень мышечных мостиков по сравнению с остальными ангиографическими исследованиями, что очень близко к цифрам с аутопсий
Effect of Composition on Electrical and Optical Properties of Thin Films of Amorphous GaxSe100−x Nanorods
We report the electrical and optical studies of thin films of a-GaxSe100−x nanorods (x = 3, 6, 9 and 12). Thin films of a-GaxSe100−x nanorods have been synthesized thermal evaporation technique. DC electrical conductivity of deposited thin films of a-GaxSe100−x nanorods is measured as a function of temperature range from 298 to 383 K. An exponential increase in the dc conductivity is observed with the increase in temperature, suggesting thereby a semiconducting behavior. The estimated value of activation energy decreases on incorporation of dopant (Ga) content in the Se system. The calculated value of pre-exponential factor (σ0) is of the order of 101 Ω−1 cm−1, which suggests that the conduction takes place in the band tails of localized states. It is suggested that the conduction is due to thermally assisted tunneling of the carriers in the localized states near the band edges. On the basis of the optical absorption measurements, an indirect optical band gap is observed in this system, and the value of optical band gap decreases on increasing Ga concentration
Multicolor Layer-by-Layer films using weak polyelectrolyte assisted synthesis of silver nanoparticles
Tunable 3D 2D magnetism in the MnBi2Te4 Bi2Te3 m topological insulators family
Feasibility of many emergent phenomena that intrinsic magnetic topological insulators (TIs) may host depends crucially on our ability to engineer and efficiently tune their electronic and magnetic structures. Here we report on a large family of intrinsic magnetic TIs in the homologous series of the van der Waals compounds (MnBi2Te4)(Bi2Te3)m with m = 0, ⋯, 6. Magnetic, electronic and, consequently, topological properties of these materials depend strongly on the m value and are thus highly tunable. The antiferromagnetic (AFM) coupling between the neighboring Mn layers strongly weakens on moving from MnBi2Te4 (m = 0) to MnBi4Te7 (m = 1) and MnBi6Te10 (m = 2). Further increase in m leads to change of the overall magnetic behavior to ferromagnetic (FM) one for (m = 3), while the interlayer coupling almost disappears. In this way, the AFM and FM TI states are, respectively, realized in the m = 0, 1, 2 and m = 3 cases. For large m numbers a hitherto-unknown topologically nontrivial phase can be created, in which below the corresponding critical temperature the magnetizations of the non-interacting 2D ferromagnets, formed by the MnBi2Te4 building blocks, are disordered along the third direction. The variety of intrinsic magnetic TI phases in (MnBi2Te4)(Bi2Te3)m allows efficient engineering of functional van der Waals heterostructures for topological quantum computation, as well as antiferromagnetic and 2D spintronics.This work is supported by Saint Petersburg State University project for scientific investigations (ID No. 51126254, https://spin.lab.spbu.ru) and Russian Science Foundation (Grant no. 18-12-00062 in part of the photoemission measurements and 18-12-00169 in part of calculations of topological invariants, investigation of dependence of the electronic spectra on SOC strength, and tight-binding band structure calculations). Russian Foundation for Basic Research (Grant nos. 20-32-70179 and 18-52-06009) and Science Development Foundation under the President of the Republic of Azerbaijan (Grant no. EIF-BGM-4-RFTF-1/2017-21/04/1-M-02) are acknowledged. We also acknowledge the support by the Basque Departamento de Educacion, UPV/EHU (Grant no. IT-756-13), Spanish Ministerio de Ciencia e Innovación (Grant no. PID2019-103910GB-I00), the Fundamental Research Program of the State Academies of Sciences (line of research III.23.2.9) and Tomsk State University competitiveness improvement program (project no. 8.1.01.2018). I.P.R. acknowledge support from Ministry of Education and Science of the Russian Federation (State Task No. 0721-2020-0033) (tight-binding calculations). The calculations were performed in Donostia International Physics Center and in the Research park of St. Petersburg State University Computing Center (http://cc.spbu.ru).Peer reviewe
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