Elastic oscillations of water column in the 2003 Tokachi-oki tsunami source: in-situ measurements and 3-D numerical modelling

International audienceDuring the 2003 Tokachi-Oki tsunamigenic earthquake the real-time JAMSTEC observatory obtained records which provided a unique opportunity to have a look deep inside the tsunami source. Considering water column as a compressible medium we processed the bottom pressure records in order to estimate amplitude, duration and velocity of bottom displacement. Spectral analysis of the records revealed a clear manifestation of the low-frequency elastic oscillations of water column. We also presented 3-D finite-difference numerical model developed in the framework of linear potential theory of ideal compressible fluid to better understand dynamical processes in the tsunami source. The model reproduces position of the main spectral maximum rather correctly. However, due to neglecting of crust elasticity and to lack of exact knowledge of spatiotemporal laws of bottom motion, there is an essential difference between in-situ observed and computed spectra

Tetrahedron maps, Yang-Baxter maps, and partial linearisations

We study tetrahedron maps, which are set-theoretical solutions to the Zamolodchikov tetrahedron equation, and Yang-Baxter maps, which are set-theoretical solutions to the quantum Yang-Baxter equation. In particular, we clarify the structure of the nonlinear algebraic relations which define linear (parametric) tetrahedron maps (with nonlinear dependence on parameters), and we present several transformations which allow one to obtain new such maps from known ones. Furthermore, we prove that the differential of a (nonlinear) tetrahedron map on a manifold is a tetrahedron map as well. Similar results on the differentials of Yang-Baxter and entwining Yang-Baxter maps are also presented. Using the obtained general results, we construct new examples of (parametric) Yang-Baxter and tetrahedron maps. The considered examples include maps associated with integrable systems and matrix groups. In particular, we obtain a parametric family of new linear tetrahedron maps, which are linear approximations for the nonlinear tetrahedron map constructed by Dimakis and M\"uller-Hoissen [arXiv:1708.05694] in a study of soliton solutions of vector Kadomtsev-Petviashvili (KP) equations. Also, we present invariants for this nonlinear tetrahedron map.Comment: 23 pages; v2: new results and references added, minor corrections mad

Contribution of nonlinearity in tsunami generated by submarine earthquake

International audienceRapid co-seismic bottom displacements during strong submarine earthquake give rise to intensive low-frequency elastic oscillations of water layer. Nonlinear energy transfer from the elastic oscillations to long gravitational waves may provide an additional contribution to tsunami. The nonlinear tsunami generation mechanism is examined analytically. Finiteness of bottom elasticity is taken into account. General parameters responsible for amplitude and energy of the nonlinear contribution to tsunami wave are revealed

The Relationship between the Digital Economy and Financial Policy in the Russian Federation: Ways to Improve

At present, the development and implementation of new information and communication technologies in all sectors of the economy is of great importance in the leading countries. In full measure, this trend also takes place in the Russian Federation (RF), where the digital economy (DE) is developing.   The main goal of the study is to, based on the relationship between the formation of the digital economy and the improvement of financial policy, firstly, to analyze this interaction.   Secondly, on this basis, to develop ways to accelerate the formation of the DE, as well as to increase the effectiveness of the FP at the federal and regional levels. Because of the study, we considered it possible and necessary to supplement with a number of positions the list of tasks already available in a number of official documents for the formation of the digital economy and the conduct of financial policy

Comparison of machine learning methods for analysis of ulcerative colitis proteomic data

Ulcerative colitis is a chronic inflammatory disease of the gastrointestinal system, affecting adults and children. Its cause is unknown, and the knowledge of reliable biomarkers is limited, especially for children. That makes the search for new biomarkers and pushing forth the analysis of the available data particularly challenging. We investigate proteomic data from children patients as a promising source, and tackle the problem implementing the recently developed parenclitic network approach to machine learning algorithms that solve classification task for proteomic data from healthy and diseased. We expect our approach to be applicable to other gastrointestinal diseases

Coherent population trapping in ruby crystal at room temperature

Observation of coherent population trapping (CPT) at ground-state Zeeman sublevels of $Cr^{3+}$-ion in ruby is reported. The experiments are performed at room temperature by using both nanosecond optical pulses and nanosecond trains of ultrashort pulses. In both cases sharp drops in the resonantly induced fluorescence are detected as the external magnetic field is varied. Theoretical analysis of CPT in a transient regime due to pulsed action of optical pulses is presented.Comment: 4 pages, 4 figures, submitted to PR