1,016 research outputs found

    Modeling of "groove" rolling defect on internal surface of pipes at lengthwise rolling

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    The research has been conducted in pipe forming at rolling off by lengthwise rolling mill with stub mandrel; the patterns of change in dimensionless parameters were determined, which characterize deformation in side angle depending on http://www.multitran.ru/c/m.exe?t=424995_2_1elongation ratio. The model of formation of lengthwise groove on internal surface of pipes has been proposed

    Образование в эпоху «экономики знаний»

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    Features of modern economy as "economy of knowledge" are defined. The changes happening in education in the conditions of strengthening of a role of knowledge in economic life of society are considered. Tasks of modern universities in production of knowledge are characterized, connection of the state, universities and business is shown. The main directions of development of modern education in the conditions of emergence of new educational technologies and pressure of market forces are proved. Proposals of rectors of higher education institutions about revival of engineering education in the Russian Federation are systematized.Определены особенности современной экономики как «экономики знаний». Рассмотрены изменения, происходящие в образовании в условиях усиления роли знаний в экономической жизни общества. Охарактеризованы задачи современных университетов в производстве знаний, показана связь государства, университетов и бизнеса. Обоснованы основные направления развития современного образования в условиях появления новых образовательных технологий и давления рыночных сил. Систематизированы предложения ректоров вузов о возрождении инженерного образования в РФ

    Streptococcus pyogenes: phenomenon of nonimmune binding of human immunoglobulins and its role in pathology

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    M and M-like proteins represent the main pathogenicity factors of Streptococcus pyogenes, a widely spread and potentially lethal bacterial pathogen. These proteins provide resistance of the microbe to innate and adaptive immune response, due to attraction of specific human proteins to the streptococcal surface. Nonimmune binding of immunoglobulins G (IgG) and A (IgA) via their Fc domains to M and M-like proteins was described over 40 years ago, but its role for the pathogenicity of Streptococcus pyogenes is far from definite resolution. The discovery of this phenomenon should be considered among quite significant achievements of modern microbiology, since it had a huge impact upon development of innovative approaches, technologies and tools for microbiological, immunological and molecular diagnostics. It also promoted fundamental studies in pathogenesis of distinct infectious states and their complications caused by S. pyogenes. The non-immune binding of host immunoglobulins was previously suggested to be important mainly in immune conditions on the surface of mucous membranes and their secretions, but not in blood plasma, whereas other studies have pointed to significance of this phenomenon in protecting microbes from phagocytosis in non-immune blood of the host. It was also shown that the effect of Fc-binding causes increased pathogenicity of streptococci both in primary focus of infection, and during chronical course of the process, thus contributing to development of autoimmune diseases caused by S. pyogenes infection and leading to tissue damage in experimental animals. The experimental autoimmune process can be prevented by administering purified Fc fragments of immunoglobulins to the animals, blocking this process at the early stages of its development. A significant place in pathogenesis of IgA nephropathy (IgAN) belongs to streptococcal diseases. IgAN has been described as a mesangial proliferative process, due to initial IgA-Fcα deposition in renal mesangium cells. The data from literature describe successful modeling of individual IgAN traits, and expand our understanding of pathogenic properties and functions of Fcα binding receptor M proteins of S. pyogenes. The data reviewed in the article also presume the relevance of recently proposed ideas about an important role of non-immune Ig binding in streptococcal diseases, even in cases that differ in their development mechanism. These studies, including possible search for tools and techniques of preventive and potentially therapeutic applications, require additional efforts to study the binding of Fc fragments of IgG and IgA to M and M-like proteins of Streptococcus pyogenes

    Electrical discharges in the atmosphere of Venus

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    Data received from Venera 11 and 12 experiments involving the electrical activity of the atmosphere of Venus show that the electrical discharges occur in the cloud layer. Their energy is roughly the same as in terrestrial lightning, but with a pulse repetition frequency of the discharges which is much greater

    Dynamics of the Free Surface of a Conducting Liquid in a Near-Critical Electric Field

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    Near-critical behavior of the free surface of an ideally conducting liquid in an external electric field is considered. Based on an analysis of three-wave processes using the method of integral estimations, sufficient criteria for hard instability of a planar surface are formulated. It is shown that the higher-order nonlinearities do not saturate the instability, for which reason the growth of disturbances has an explosive character.Comment: 19 page

    Comparative performance of MRI-derived PRECISE scores and delta-radiomics models for the prediction of prostate cancer progression in patients on active surveillance

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    Objectives: To compare the performance of the PRECISE scoring system against several MRI-derived delta-radiomics models for predicting histopathological prostate cancer (PCa) progression in patients on active surveillance (AS). // Methods: The study included AS patients with biopsy-proven PCa with a minimum follow-up of 2 years and at least one repeat targeted biopsy. Histopathological progression was defined as grade group progression from diagnostic biopsy. The control group included patients with both radiologically and histopathologically stable disease. PRECISE scores were applied prospectively by four uro-radiologists with 5–16 years’ experience. T2WI- and ADC-derived delta-radiomics features were computed using baseline and latest available MRI scans, with the predictive modelling performed using the parenclitic networks (PN), least absolute shrinkage and selection operator (LASSO) logistic regression, and random forests (RF) algorithms. Standard measures of discrimination and areas under the ROC curve (AUCs) were calculated, with AUCs compared using DeLong’s test. // Results: The study included 64 patients (27 progressors and 37 non-progressors) with a median follow-up of 46 months. PRECISE scores had the highest specificity (94.7%) and positive predictive value (90.9%), whilst RF had the highest sensitivity (92.6%) and negative predictive value (92.6%) for predicting disease progression. The AUC for PRECISE (84.4%) was non-significantly higher than AUCs of 81.5%, 78.0%, and 80.9% for PN, LASSO regression, and RF, respectively (p = 0.64, 0.43, and 0.57, respectively). No significant differences were observed between AUCs of the three delta-radiomics models (p-value range 0.34–0.77). // Conclusions: PRECISE and delta-radiomics models achieved comparably good performance for predicting PCa progression in AS patients

    A versatile cryogenic system for liquid argon detectors

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    Detectors for direct dark matter search using noble gases in liquid phase as detection medium need to be coupled to liquefaction, purification and recirculation systems. A dedicated cryogenic system has been assembled and operated at the INFN-Naples cryogenic laboratory with the aim to liquefy and purify the argon used as active target in liquid argon detectors to study the scintillation and ionization signals detected by large SiPMs arrays. The cryogenic system is mainly composed of a double wall cryostat hosting the detector, a purification stage to reduce the impurities below one part per billion level, a condenser to liquefy the argon, a recirculation gas panel connected to the cryostat equipped with a custom gas pump. The main features of the cryogenic system are reported as well as the performances, long term operations and stability in terms of the most relevant thermodynamic parameters.Comment: Prepared for submission to JINST - LIDINE2022 September 21-23, 2022 - University of Warsaw Librar

    Solar neutrino detection in a large volume double-phase liquid argon experiment

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    Precision measurements of solar neutrinos emitted by specific nuclear reaction chains in the Sun are of great interest for developing an improved understanding of star formation and evolution. Given the expected neutrino fluxes and known detection reactions, such measurements require detectors capable of collecting neutrino-electron scattering data in exposures on the order of 1 ktonne yr, with good energy resolution and extremely low background. Two-phase liquid argon time projection chambers (LAr TPCs) are under development for direct Dark Matter WIMP searches, which possess very large sensitive mass, high scintillation light yield, good energy resolution, and good spatial resolution in all three cartesian directions. While enabling Dark Matter searches with sensitivity extending to the "neutrino floor" (given by the rate of nuclear recoil events from solar neutrino coherent scattering), such detectors could also enable precision measurements of solar neutrino fluxes using the neutrino-electron elastic scattering events. Modeling results are presented for the cosmogenic and radiogenic backgrounds affecting solar neutrino detection in a 300 tonne (100 tonne fiducial) LAr TPC operating at LNGS depth (3,800 meters of water equivalent). The results show that such a detector could measure the CNO neutrino rate with ~15% precision, and significantly improve the precision of the 7Be and pep neutrino rates compared to the currently available results from the Borexino organic liquid scintillator detector.Comment: 21 pages, 7 figures, 6 table

    Development Of Software–Hardware System for Real Time Simulation of Electric Power System with Smart Grids

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    The design and research of electric power system (EPS) with smart grids (SG), which are the current world trend of modern electric power industry, requires solving a large number of non-trivial tasks. The developed technical solutions and used equipment are novel for the world practice. Therefore, their implementation requires carefulanalysis and an individual approach to research that provides an assessment of the impact of new network elements on the power system. All of this puts requirements on the tools and methods of research used to solve such problems. At present, digital systems for modelling EPS with SG based on the application of numerical methods are used as such tools. However, despite the high level of these developments, it has drawbacks. The use of incomplete and invalid information obtained by digital tools can lead to the wrong design and operational decision in real power system, which can cause blackouts. The alternative approach for solving the problem of detailed simulation of EPS with SG is the creation of hybrid system based on the principle of combining different modelling methods. Hybrid Real-Time Power System Simulator (HRTSim) is developed based on this approach and presented in the paper
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