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Search Results: 1 - 10 of 276078 matches for " E. V. Demidova "
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Forecasting Method for Grouped Time Series with the Use of k-Means Algorithm
N. N. Astakhova,L. A. Demidova,E. V. Nikulchev
Computer Science , 2015, DOI: 10.12988/ams.2015.55391
Abstract: The paper is focused on the forecasting method for time series groups with the use of algorithms for cluster analysis. $K$-means algorithm is suggested to be a basic one for clustering. The coordinates of the centers of clusters have been put in correspondence with summarizing time series data the centroids of the clusters. A description of time series, the centroids of the clusters, is implemented with the use of forecasting models. They are based on strict binary trees and a modified clonal selection algorithm. With the help of such forecasting models, the possibility of forming analytic dependences is shown. It is suggested to use a common forecasting model, which is constructed for time series the centroid of the cluster, in forecasting the private (individual) time series in the cluster. The promising application of the suggested method for grouped time series forecasting is demonstrated.
Rheumatoid Factor Positivity Is Associated with Increased Joint Destruction and Upregulation of Matrix Metalloproteinase 9 and Cathepsin K Gene Expression in the Peripheral Blood in Rheumatoid Arthritic Patients Treated with Methotrexate
Elena V. Tchetina,Natalia V. Demidova,Dmitry E. Karateev,Eugeny L. Nasonov
International Journal of Rheumatology , 2013, DOI: 10.1155/2013/457876
Abstract: We evaluated changes in gene expression of mTOR, p21, caspase-3, ULK1, TNFα, matrix metalloproteinase (MMP)-9, and cathepsin K in the whole blood of rheumatoid arthritic (RA) patients treated with methotrexate (MTX) in relation to their rheumatoid factor status, clinical, immunological, and radiological parameters, and therapeutic response after a 24-month follow-up. The study group consisted of 35 control subjects and 33 RA patients without previous history of MTX treatment. Gene expression was measured using real-time RT-PCR. Decreased disease activity in patients at the end of the study was associated with significant downregulation of TNFα expression. Downregulation of mTOR was observed in seronegative patients, while no significant changes in the expression of p21, ULK1, or caspase-3 were noted in any RA patients at the end of the study. The increase in erosion numbers observed in the seropositive patients at the end of the follow-up was accompanied by upregulation of MMP-9 and cathepsin K, while seronegative patients demonstrated an absence of significant changes in MMP-9 and cathepsin K expression and no increase in the erosion score. Our results suggest that increased expression of MMP-9 and cathepsin K genes in the peripheral blood might indicate higher bone tissue destruction activity in RA patients treated with methotrexate. The clinical study registration number is 0120.0810610. 1. Introduction Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial hyperplasia, mononuclear cell infiltration, bone erosion, and joint destruction. Early diagnosis and immediate aggressive treatment are required for the amelioration of progressive joint damage and patient disability [1, 2]. Methotrexate (MTX) is the most conventional disease-modifying antirheumatic drug (DMARD) for RA, with the best efficacy and the fewest adverse effects [3, 4]. However, only approximately 30% of patients respond to MTX treatment [5, 6]. The identification of patients who are less responsive to MTX could avoid delays in adjusting their treatment and prevent future irreversible joint damage [7]. Rheumatoid factor (RF) is a part of the 2010 American College of Rheumatology (ACR) classification criteria for RA [8]. RF is an autoantibody directed against the Fc portion of IgG and is associated with disease persistence and progressive joint destruction [9–11]. However, the data related to RF status in treatment response to MTX is inconsistent, as some studies reported no association between RF positivity and treatment efficacy [12–21], while others
On the Feasibility of Low-Background Ge-NaI Spectrometer for Neutrino Magnetic Moment Measurement
A. G. Beda,E. V. Demidova,A. S. Starostin,M. B. Voloshin
Physics , 1997,
Abstract: We analyze the possibility of using a low-background Ge-NaI spectrometer in a reactor experiment for a search for neutrino magnetic moment down to $3 \times 10^{-11}$ of the electron magneton. The properties of the so-far existing Ge low-background spectrometers are discussed and additional sources of background in a reactor experiment at a small depth are estimated. These estimates place specific requirements on the design of the spectrometer. The results of preliminary background measurements at a small depth of 5 m.w.e. with a dedicated spectrometer built in ITEP are reported.
GEMMA experiment: three years of the search for the neutrino magnetic moment
A. G. Beda,V. B. Brudanin,E. V. Demidova,V. G. Egorov,D. V. Medvedev,M. V. Shirchenko,A. S. Starostin,Ts. Vylov
Physics , 2009, DOI: 10.1134/S1547477110060063
Abstract: The result of the 3-year neutrino magnetic moment measurement at the Kalinin Nuclear Power Plant with the GEMMA spectrometer is presented. Antineutrino-electron scattering is investigated. A high-purity germanium detector of 1.5 kg placed at a distance of 13.9 m from the 3 GW(th) reactor core is used in the spectrometer. The antineutrino flux is 2.7E13 1/scm/s. The differential method is used to extract (nu-e) electromagnetic scattering events. The scattered electron spectra taken in 5184+6798 and 1853+1021 hours for the reactor ON and OFF periods are compared. The upper limit for the neutrino magnetic moment < 3.2E-11 Bohr magneton at 90% CL is derived from the data processing.
Formation of 24Mg* in the Splitting of 28Si Nuclei by 1-GeV Protons
A. A. Vasenko,N. D. Galanina,K. E. Gusev,V. S. Demidov,E. V. Demidova,I. V. Kirpichnikov,A. Yu. Sokolov,A. S. Starostin,N. A. Khaldeeva
Physics , 2006, DOI: 10.1134/S0021364006180172
Abstract: The 28Si(p, p' gamma)24Mg reaction has been studied at the ITEP accelerator by the hadron-gamma coincidence method for a proton energy of 1 GeV. Two reaction products are detected: a 1368.6-keV gamma-ray photon accompanying the transition of the 24Mg* nucleus from the first excited state to the ground state and a proton p' whose momentum is measured in a magnetic spectrometer. The measured distribution in the energy lost by the proton in interaction is attributed to five processes: the direct knockout of a nuclear alpha cluster, the knockout of four nucleons with a total charge number of 2, the formation of the DeltaSi isobaric nucleus, the formation of the Delta isobar in the interaction of the incident proton with a nuclear nucleon, and the production of a pi meson, which is at rest in the nuclear reference frame. The last process likely corresponds to the reaction of the formation of a deeply bound pion state in the 28P nucleus. Such states were previously observed only on heavy nuclei. The cross sections for the listed processes have been estimated.
The first result of the neutrino magnetic moment measurement in the GEMMA experiment
A. G. Beda,V. B. Brudanin,E. V. Demidova,V. G. Egorov,M. G. Gavrilov,M. V. Shirchenko,A. S. Starostin,Ts. Vylov
Physics , 2007, DOI: 10.1134/S1063778807110063
Abstract: The first result of the neutrino magnetic moment measurement at the Kalininskaya Nuclear Power Plant (KNPP) with the GEMMA spectrometer is presented. An antineutrino-electron scattering is investigated. A high-purity germanium detector of 1.5 kg placed 13.9 m away from the 3 GW reactor core is used in the spectrometer. The antineutrino flux is $2.73\times 10^{13} \nu_e / cm^2 / s$. The differential method is used to extract the $\nu$-e electromagnetic scattering events. The scattered electron spectra taken in 6200 and 2064 hours for the reactor ON and OFF periods are compared. The upper limit for the neutrino magnetic moment $\mu_\nu < 5.8\times 10^{-11}$ Bohr magnetons at 90{%} CL is derived from the data processing.
Experimental Study of the Acoustic Field Generated by a 50 MeV Electron Beam in Water
V. B. Bychkov,V. S. Demidov,E. V. Demidova,A. N. Ermakov,O. D. Ershova,B. S. Ishkhanov,V. P. Maslyany,A. Yu. Sokolov,N. A. Khaldeeva
Physics , 2006,
Abstract: At the MSU SINP electron accelerator, a space-time dependence of the acoustic pressure generated in water by an electron beam of 50 MeV energy was obtained. Measurements were carried out in 100 points located along the line parallel to the beam axis at the distance of 6.5 cm from the axis. At a two-dimensional diagram (distance-time) two signal tracks were observed from two sound sources: a cylindrical acoustic antenna generated by the electron beam, and an area of the beam entrance cap which divides the water medium from the air.
Discrete tunneling in granulated substances and other similar mediums
E. S. Demidov,N. E. Demidova
Physics , 2013,
Abstract: Work is devoted to physics of current transport in a wide class of the hetero-phase granulated mediums and similar systems with set of metal or semi-conductor granules, quantum dots or potential wells in which the exit from Coulomb blockade tunneling regime can be not observable because of irreversible breakdown and destruction of structure of medium. Such systems also concern and the condensed mediums with short distanced atoms of transition elements. In article for small and average electric fields the analytical decision of a stationary problem of discrete electronic transport through a chain of as much as big number of metal granules in area Coulomb tunneling blockade is performed. It is deduced the exponential law of growth of a current with electric field in such granulated systems. The characteristic feature of discrete tunneling in such medium is the volt-ampere characteristic type I exp(V/(N+1)kT) with great value N>> 1. Examples of application of the theory for explanation of current transport in porous silicon, synthesised by ionic implantation of nitrogen in silicon layers of nitride of silicon or glass like amorphous semiconductors are resulted.
Spiral patterns in planetesimal circumbinary disks
Tatiana V. Demidova,Ivan I. Shevchenko
Physics , 2014, DOI: 10.1088/0004-637X/805/1/38
Abstract: Planet formation scenarios and the observed planetary dynamics in binaries pose a number of theoretical challenges, especially in what concerns circumbinary planetary systems. We explore the dynamical stirring of a planetesimal circumbinary disk in the epoch when the gas component disappears. For this purpose, following theoretical approaches by Heppenheimer (1978) and Moriwaki and Nakagawa (2004), we develop a secular theory for the dynamics of planetesimals in circumbinary disks. If the binary is eccentric and its components have unequal masses, a spiral density wave is generated, engulfing the disk on the secular timescale, which may exceed 10^7 yr, depending on the problem parameters. The spiral pattern is transient; thus, its observed presence may betray system's young age. We explore the pattern both analytically and in numerical experiments. The derived analytical spiral is a modified lituus; it matches the numerical density wave in the gas-free case perfectly. Using the SPH scheme, we explore the effect of residual gas on the wave propagation.
Brightness Oscillations in Models of Young Binary Systems with Low-Mass Secondary Components
T. Demidova,V. Grinin,N. Sotnikova
Physics , 2011, DOI: 10.1134/S1063773710070054
Abstract: We consider a model for the cyclic brightness variations of a young star with a low-mass companion that accretes matter from the remnants of a protostellar cloud. At small inclinations of the binary orbit to the line of sight, the streams of matter and the density waves excited in the circumbinary disk can screen the primary component of the binary from the observer. To study these phenomena, we have computed grids of hydrodynamic models for binary systems by the SPH method based on which we have constructed the phase light curves as a function of the rotation angle of the apsidal line relative to the observer. The model parameters were varied within the following ranges: the component mass ratio q = 0.01-0.1 and the eccentricity e = 0-0.5. We adopted optical grain characteristics typical of circumstellar dust. Our computations have shown that the brightness oscillations with orbital phase can have a complex structure. The amplitudes and shapes of the light curves depend strongly on the inclination of the binary orbit and its orientation relative to the observer and on the accretion rate. The results of our computations are used to analyze the cyclic activity of UX Ori stars.
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