Crustal structure below Popocat\'epetl Volcano (Mexico) from analysis of Rayleigh waves

An array of ten broadband stations was installed on the Popocat\'epetl volcano (Mexico) for five months between October 2002 and February 2003. 26 regional and teleseismic earthquakes were selected and filtered in the frequency time domain to extract the fundamental mode of the Rayleigh wave. The average dispersion curve was obtained in two steps. Firstly, phase velocities were measured in the period range [2-50] s from the phase difference between pairs of stations, using Wiener filtering. Secondly, the average dispersion curve was calculated by combining observations from all events in order to reduce diffraction effects. The inversion of the mean phase velocity yielded a crustal model for the volcano which is consistent with previous models of the Mexican Volcanic Belt. The overall crustal structure beneath Popocat\'epetl is therefore not different from the surrounding area, and the velocities in the lower crust are confirmed to be relatively low. Lateral variations of the structure were also investigated by dividing the network into four parts and by applying the same procedure to each sub-array. No well-defined anomalies appeared for the two sub-arrays for which it was possible to measure a dispersion curve. However, dispersion curves associated with individual events reveal important diffraction for 6 s to 12 s periods which could correspond to strong lateral variations at 5 to 10 km depth

Determination of Fluorescence Polarization and Absorption Anisotropy in Molecular Complexes Having Threefold Rotational Symmetry

The current work concerns investigation of the polarization properties of complex molecular ensembles exhibiting threefold (C3) rotational symmetry, particularly with regard to the interplay between their structure and dynamics of internal energy transfer. We assume that the molecules or chromophores in such complexes possess strongly overlapped spectra both for absorption and fluorescence. Such trimeric structures are widely found in biological preparations, as for example the trimer of C-phycocyanin (C-PC). Higher order aggregates, e.g. hex-amers and three-hexamer rods, are also investigated and compared with the trimer case. The theory addresses both steady-state and 8-pulse excitation and establishes some links between them. Monochromophoric, bichro-mophoric and trichromophoric molecular complexes are individually examined. For steady-state excitation, analytical formulas are reported for the degree of fluorescence polarization and absorption anisotropy. It is shown that the polarization is dependent on the chromophore inclination relative to the symmetry axis, the relative efficiencies of absorption and fluorescence by chromophores of different spectral types, and the rates of energy equilibration. To assess the validity of the theory, it has been applied to C-PC aggregates. Here it was found that different C-PC aggregates provide practically identical polarization response. For S-pulse excitation we give analytical formulas for determination of the fluorescence depolarization, and also the depolarization associated with absorption recovery, both for a monochromophoric trimer and some particular cases of bichromophoric trimer. More complicated systems are analyzed by computer modeling. Thus it transpires that the initial polarization anisotropy r(t = 0) takes the value 0.4 for all considered aggregates; the long-time limit r(t →∞) has about the same value as is associated with steady-state excitation. We also show that with steady-state excitation the degree of fluorescence polarization is practically equal for various C3 aggregates of C-PC, and that the major factor determining the polarization is the chromophore orientation relative to the symmetry axis

Surface wave tomography across Afar, Ethiopia: crustal structure at a rift triple-junction zone

The Afar Depression in northeast Africa contains the rift triple-junction between the Nubia, Arabia and Somalia plates. We analyze Rayleigh wave group velocity from 250 regional earthquakes recorded by 40 broadband stations to study the crustal structure across Afar and adjacent plateau regions in northern Ethiopia. The dispersion velocities are inverted to obtain surface wave tomographic maps for periods between 5 and 25 seconds, sensitive to approximately the top 30 km of the lithosphere. The tomographic maps show a significant low dispersion velocity anomaly (>20%) within the upper crust, below the site of recent dyke intrusions (2005–present) in the Dabbahu and Manda-Hararo magmatic segments. Similar low velocity regions are imaged where magma intrusion in the Afar crust has been inferred over the last decade from seismicity or volcanic eruptions. We invert two group velocity curves to compare the S-wave velocity structure of the crust within an active magmatic segment with that of adjacent areas; the active region has a low velocity zone (Vs ∼ 3.2 km/s), between about 6–12 km, which we infer to be due to the presence of partial melt within the lower crust

Further Remarks on Extra Roots of Rayleigh Equation and Somigliana Waves

The extra roots of the Rayleigh equation for an elastichalfspace contribute to the solution only for large enough values of thePoisson coefficient (a > 0.309). One of them corresponds to leaking modeswith the phase velocity less than the velocity of the longitudinal wave.A similar wave with distinct dispersion may exists in the case where anelastic halfspace is covered by a thin layer with lower velocities of elasticwaves. The thickness of a layer should be not too small in comparisonwith the wave length

Applications of artificial intelligence to identify fake accounts: Psychological and legal aspects

This article analyzes the threats posed by the proliferation of fake accounts in today's information society. The authors consider the history of the emergence and development of this problem, as well as the ways proposed by governments and the international scientific community to address it. In search of a viable solution, they compare various methods for limiting the spread of fake accounts. They suggest using artificial intelligence technology as a promising alternative. As a training basis for AI, the authors propose analyzing the behavioral motivations of those who create fake accounts, in order to utilize a trained behavioral analytics system to combat fakes automatically. Along with key principles for using behavioral metrics, the authors provide various examples that illustrate the feasibility and effectiveness of their proposed solution. Special attention is paid to the legal aspects of implementing the proposed solution, as the process of detecting fake accounts is intricately linked to the processing of biometric and other personal data. The requirements for the storage and processing of personal data are becoming stricter every year. Therefore, in order to limit the spread of fake accounts, it is essential to find a solution that complies with information legislation

Use of Glauconite in Potato Cultivation Technology

In intensive technologies of cultivation of potatoes, the need for trace elements is increasing. The concentration of trace elements in plants is very small, but the importance of these elements in biochemical processes is difficult to overestimate. The deficiency of trace elements is the root cause of many functional disorders. Trace elements in plants are part of enzymes, stimulate and accelerate plant development, increase resistance to adverse environmental conditions, etc. Also, with their shortage, crop productivity decreases. The use of natural minerals, such as glauconite, containing trace elements, allows improving comprehensive nutrition and increase productivity. Getting early production of high quality potatoes in the summer is important and relevant in the modern world. The use of glauconite in the conditions of the Moscow region, along with fertilizers and irrigation, allows obtaining high-quality products and increasing productivity by 6.3... 29.0%

The crust and upper mantle structure of central and West Antarctica from Bayesian inversion of Rayleigh Wave and receiver functions

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 123 (2018): 7824-7849, doi:10.1029/2017JB015346.We construct a new seismic model for central and West Antarctica by jointly inverting Rayleigh wave phase and group velocities along with P wave receiver functions. Ambient noise tomography exploiting data from more than 200 seismic stations deployed over the past 18 years is used to construct Rayleigh wave phase and group velocity dispersion maps. Comparison between the ambient noise phase velocity maps with those constructed using teleseismic earthquakes confirms the accuracy of both results. These maps, together with P receiver function waveforms, are used to construct a new 3‐D shear velocity (Vs) model for the crust and uppermost mantle using a Bayesian Monte Carlo algorithm. The new 3‐D seismic model shows the dichotomy of the tectonically active West Antarctica (WANT) and the stable and ancient East Antarctica (EANT). In WANT, the model exhibits a slow uppermost mantle along the Transantarctic Mountains (TAMs) front, interpreted as the thermal effect from Cenozoic rifting. Beneath the southern TAMs, the slow uppermost mantle extends horizontally beneath the traditionally recognized EANT, hypothesized to be associated with lithospheric delamination. Thin crust and lithosphere observed along the Amundsen Sea coast and extending into the interior suggest involvement of these areas in Cenozoic rifting. EANT, with its relatively thick and cold crust and lithosphere marked by high Vs, displays a slower Vs anomaly beneath the Gamburtsev Subglacial Mountains in the uppermost mantle, which we hypothesize may be the signature of a compositionally anomalous body, perhaps remnant from a continental collision.National Science Foundation Grant Numbers: PLR‐1142518, PLR‐1246712, PLR 1246151, PLR‐1246416, PLR‐1744883, PLR‐ 17448832019-03-2

THE THEORY OF LEGAL FACTS IN VARIOUS LEGAL SYSTEMS

The article provides an overview of the process of the theory of legal facts formation and development in various legal systems. The perception features of this theory in the continental Western Europe countries, the Anglo-Saxon legal system, as well as in Russia are revealed. The conclusion is made that currently in Russia there is an active development of the theory of legal facts. It is filled with new content and elements. Great importance is attached to the study of large factual systems that identified by Russian jurists

Application of Surface wave methods for seismic site characterization

Surface-wave dispersion analysis is widely used in geophysics to infer a shear wave velocity model of the subsoil for a wide variety of applications. A shear-wave velocity model is obtained from the solution of an inverse problem based on the surface wave dispersive propagation in vertically heterogeneous media. The analysis can be based either on active source measurements or on seismic noise recordings. This paper discusses the most typical choices for collection and interpretation of experimental data, providing a state of the art on the different steps involved in surface wave surveys. In particular, the different strategies for processing experimental data and to solve the inverse problem are presented, along with their advantages and disadvantages. Also, some issues related to the characteristics of passive surface wave data and their use in H/V spectral ratio technique are discussed as additional information to be used independently or in conjunction with dispersion analysis. Finally, some recommendations for the use of surface wave methods are presented, while also outlining future trends in the research of this topic

Charlson comorbidity index in predicting deaths in COVID-19 patients

Aim. To assess the clinical performance and factors associated with inhospital mortality in patients with coronavirus disease 2019 (COVID-19).Material and methods. Our results are based on data from hospital charts of inpatients hospitalized in the Asinovskaya District Hospital in the period from March 11, 2020 to December 31, 2020, with a verified COVID-19 by polymerase chain reaction. The study included 151 patients, the median age of which was 66,2 (50- 92) years (women, 91; 60,3%). The study endpoints were following hospitalization outcomes: discharge or death. Depending on the outcomes, the patients were divided into 2 groups: the 1st group included 138 patients (survivors), while the 2nd one included 13 patients (death). To objectify the severity of multimorbidity status, the Charlson comorbidity index was used. The final value was estimated taking into account the patient age by summing the points assigned to a certain nosological entity using a calculator table.Results. Hypertension was recorded in the majority of patients — 79,5%, chronic kidney disease — in 61,1%. The prevalence of type 2 diabetes and coronary artery disease was high — 31,8% each. Prior myocardial infarction was diagnosed in 11,3% of cases. The prevalence of percutaneous coronary intervention and coronary bypass surgery was 5,3% and 3,3%, respectively. Stroke was detected in 9,3% of participants. Prior chronic pulmonary pathologies in COVID-19 patients were rare (asthma — 3,3%, chronic obstructive pulmonary disease — 2,0%). In order to predict the death risk in COVID-19 patients, a logistic regression analysis was performed, which showed that age and Charlson comorbidity index were the most significant predictors.Conclusion. Independent factors of inhospital mortality were age and Charlson’s comorbidity index. The risk assessment model will allow clinicians to identify patients with a poor prognosis at an earlier disease stage, thereby reducing mortality by implementing more effective COVID-19 treatment strategies in conditions with limited medical resources