22 research outputs found

    The accuracy of merging approximation in generalized St. Petersburg games

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    Merging asymptotic expansions of arbitrary length are established for the distribution functions and for the probabilities of suitably centered and normalized cumulative winnings in a full sequence of generalized St. Petersburg games, extending the short expansions due to Cs\"org\H{o}, S., Merging asymptotic expansions in generalized St. Petersburg games, \textit{Acta Sci. Math. (Szeged)} \textbf{73} 297--331, 2007. These expansions are given in terms of suitably chosen members from the classes of subsequential semistable infinitely divisible asymptotic distribution functions and certain derivatives of these functions. The length of the expansion depends upon the tail parameter. Both uniform and nonuniform bounds are presented.Comment: 30 pages long version (to appear in Journal of Theoretical Probability); some corrected typo

    Forest Biomass Observation: Current State and Prospective

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    With this article, we provide an overview of the methods, instruments and initiatives for forest biomass observation at a global scale. We focus on the freely available information provided by both remote and in-situ observations. The advantages and limitation of various space borne methods, including optical, radar (C, L and P band) and LiDAR, as well as respective instruments available on the orbit (MODIS, Proba-V, Landsat, Sentinel-1, Sentinel-2 , ALOS PALSAR, Envisat ASAR) or expecting (BIOMASS, GEDI, NISAR, SAOCOM-CS) are discussed. We emphasize the role of in-situ methods in the development of a biomass models, providing calibration and validation of remote sensing data. We focus on freely available forest biomass maps, databases and empirical models. We describe the functionality of Biomass.Geo-Wiki.org portal, which provides access to a collection of global and regional biomass maps in full resolution with unified legend and units overplayed with high-resolution imagery. The Forest-Observation-System.net is announced as an international cooperation to establish a global in-situ forest biomass database to support earth observation and to encourage investment in relevant field-based observations and science. Prospects of unmanned aerial vehicles in the forest inventory are briefly discussed. The work was partly supported by ESA IFBN project (contract 4000114425/15/NL/FF/gp)

    Nature of Sonoluminescence: Noble Gas Radiation Excited by Hot Electrons in "Cold" Water

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    We show that strong electric fields occurring in water near the surface of collapsing gas bubbles because of the flexoelectric effect can provoke dynamic electric breakdown in a micron-size region near the bubble and consider the scenario of the SBSL. The scenario is: (i) at the last stage of incomplete collapse of the bubble the gradient of pressure in water near the bubble surface has such a value and sign that the electric field arising from the flexoelectric effect exceeds the threshold field of the dynamic electrical breakdown of water and is directed to the bubble center; (ii) mobile electrons are generated because of thermal ionization of water molecules near the bubble surface; (iii) these electrons are accelerated in ''cold'' water by the strong electric fields; (iv) these hot electrons transfer noble gas atoms dissolved in water to high-energy excited states and optical transitions between these states produce SBSL UV flashes in the trasparency window of water; (v) the breakdown can be repeated several times and the power and duration of the UV flash are determined by the multiplicity of the breakdowns. The SBSL spectrum is found to resemble a black-body spectrum where temperature is given by the effective temperature of the hot electrons. The pulse energy and some other characteristics of the SBSL are found to be in agreement with the experimental data when realistic estimations are made.Comment: 11 pages (RevTex), 1 figure (.ps

    Upbringing of Student Teachers in Extracurricular Activities in the Context of Distance Learning

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    Introduction of distance technologies is necessary in the professional training of students, despite various assessments of its effectiveness. The purpose of the study is to develop the students’ upbringing system in a distance format and experimentally prove its impact on the main directions of future teachers’ upbringing, in comparison with off-line extracurricular activities. 156 undergraduate students took part in the experiment. Experimental research is the author’s paradigm for the formation of youth upbringing in extracurricular activities, which includes six synergistically interrelated areas. The students’ upbringing system developed in the study was tested in two formats of implementation: in off-line format at the first stage of the study and in distance format at the second stage. The statistical data obtained confirm the effectiveness of extracurricular activities for the formation of the future teachers’ upbringing only in off-line format. The introduction of distance technologies in the implementation of upbringing extracurricular activities does not have a positive effect on students, but in some areas has an opposite negative effect. The practical significance of the study is determined by the introduction of a self-analysis and monitoring system into the educational process through the use of Facebook and VKontakte social networks

    Immunohistochemical expression of nanog protein in prostate cancer cells of distinct grade groups [ИММУНОГИСТОХИМИЧЕСКАЯ ЭКСПРЕССИЯ БЕЛКА NANOG В КЛЕТКАХ РАКА ПРЕДСТАТЕЛЬНОЙ ЖЕЛЕЗЫ РАЗЛИЧНЫХ ПРОГНОСТИЧЕСКИХ ГРУПП]

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    Prostate cancer is the most common type of cancer among men, which is mainly due to extensive use of screening tests and high total number of prostate biopsies. Verification of tumors with poorer prognosis is the primary goal of prostate cancer management. The study was aimed to determine the clinical and morphological associations and the prognostic value of the Nanog protein expression in prostate cancer of distinct Grade Groups. We used the prostate tissue specimens obtained during surgery, and the biopsy specimens, the total of 89 cases. Histological and immunohistochemical assessment was performed using antibodies to Ki-67 and Nanog. Correlations between the expression of markers and the Grade Groups were revealed using the Spearman's rank correlation coefficient, and the correlation with clinical and morphological characteristics was determined using the chi-squared test (χ2). There was a positive correlation between the expression of Ki-67 and Nanog, and the Grade Group numerical order (rs = 0.619, p < 0.001 and rs = 0.786, p < 0.001 respectively). We managed to find the relationship between the high Nanog expression and the extraprostatic extension (p = 0.041). High expression of Nanog protein in the prostate cancer cells was associated with a higher-grade adenocarcinoma and indicated a poor prognosis. © 2020 Pirogov Russian National Research Medical University. All rights reserved
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