Large-volume silicic volcanism in Kamchatka: Ar–Ar and U–Pb ages, isotopic, and geochemical characteristics of major pre-Holocene caldera-forming eruptions

The Kamchatka Peninsula in far eastern Russia represents the most volcanically active arc in the world in terms of magma production and the number of explosive eruptions. We investigate large-scale silicic volcanism in the past several million years and present new geochronologic results from major ignimbrite sheets exposed in Kamchatka. These ignimbrites are found in the vicinity of morphologically-preserved rims of partially eroded source calderas with diameters from ∼ 2 to ∼ 30 km and with estimated volumes of eruptions ranging from 10 to several hundred cubic kilometers of magma. We also identify and date two of the largest ignimbrites: Golygin Ignimbrite in southern Kamchatka (0.45 Ma), and Karymshina River Ignimbrites (1.78 Ma) in south-central Kamchatka. We present whole-rock geochemical analyses that can be used to correlate ignimbrites laterally. These large-volume ignimbrites sample a significant proportion of remelted Kamchatkan crust as constrained by the oxygen isotopes. Oxygen isotope analyses of minerals and matrix span a 3‰ range with a significant proportion of moderately low-δ18O values. This suggests that the source for these ignimbrites involved a hydrothermally-altered shallow crust, while participation of the Cretaceous siliceous basement is also evidenced by moderately elevated δ18O and Sr isotopes and xenocryst contamination in two volcanoes. The majority of dates obtained for caldera-forming eruptions coincide with glacial stages in accordance with the sediment record in the NW Pacific, suggesting an increase in explosive volcanic activity since the onset of the last glaciation 2.6 Ma. Rapid changes in ice volume during glacial times and the resulting fluctuation of glacial loading/unloading could have caused volatile saturation in shallow magma chambers and, in combination with availability of low-δ18O glacial meltwaters, increased the proportion of explosive vs effusive eruptions. The presented results provide new constraints on Pliocene–Pleistocene volcanic activity in Kamchatka, and thus constrain an important component of the Pacific Ring of Fire

Dynamical mean-field approach to materials with strong electronic correlations

We review recent results on the properties of materials with correlated electrons obtained within the LDA+DMFT approach, a combination of a conventional band structure approach based on the local density approximation (LDA) and the dynamical mean-field theory (DMFT). The application to four outstanding problems in this field is discussed: (i) we compute the full valence band structure of the charge-transfer insulator NiO by explicitly including the p-d hybridization, (ii) we explain the origin for the simultaneously occuring metal-insulator transition and collapse of the magnetic moment in MnO and Fe2O3, (iii) we describe a novel GGA+DMFT scheme in terms of plane-wave pseudopotentials which allows us to compute the orbital order and cooperative Jahn-Teller distortion in KCuF3 and LaMnO3, and (iv) we provide a general explanation for the appearance of kinks in the effective dispersion of correlated electrons in systems with a pronounced three-peak spectral function without having to resort to the coupling of electrons to bosonic excitations. These results provide a considerable progress in the fully microscopic investigations of correlated electron materials.Comment: 24 pages, 14 figures, final version, submitted to Eur. Phys. J. for publication in the Special Topics volume "Cooperative Phenomena in Solids: Metal-Insulator Transitions and Ordering of Microscopic Degrees of Freedom

The study of economic features of taxation of profits of organizations in Russian Federation in the 2010

This article presents the main results of research on the topic of The research of the economic features of the corporate profit tax in the Russian Federation in the 2010s. The paper provides an overview of the international practice of the evolution of corporate profit taxation. Corporate profit tax is not optimal, since it distorts the decisions made by the company: about the source of funding (if interests on loans can be deducted from corporate profit tax base), about dividend payments (if the classical system with double taxation of distributed profits is applied), investment decisions, etc. In the framework of this work, the economic effects of distortions caused by the corporate profit tax in the Russian Federation and methods of their minimization will be analyzed, and the estimation of the scale of this distortions will be provided

NEURAL NETWORKS ART WITH SEVERAL FIELDS BY NEURAL

На основе нейронной сети адаптивной резонансной теории (АРТ) разработана архитектура и алгоритмы функционирования стабильно-пластичной дискретной нейронной сети АРТ с несколькими полями. Новая нейронная сеть предназначена для ускорения процессов обнаружения сигналов, ведущих к рискам сбоев, при моделировании цифровых устройств.На основі нейронної мережі адаптивної резонансної теорії (АРТ) розроблена архітектура та алгоритми функціонування стабільно-пластичної дискретної нейронної мережі АРТ з декількома полями. Нова нейронна мережа призначена для прискорення процесів виявлення сигналів, провідних до ризиків збоїв, при моделюванні цифрових пристроїв.Based on neural network adaptive resonance theory (ART) architecture and algorithms developed stable operation of plastic-discrete neural network ART with several fields. A new neural network is designed to accelerate the processes of signal detection, leading to risk failure, in the simulation digital devices