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Search Results: 1 - 10 of 462229 matches for " A. Nikolaev "
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Innovative antihypertensive therapy in the light of completed clinical trials
N. A. Nikolaev
Rational Pharmacotherapy in Cardiology , 2009,
Abstract: The innovative approaches to antihypertensive pharmacotherapy and advantages of modern antihypertensive drugs are discussed on the basis of randomized controlled trial. The recommendations for usage of different class of antihypertensive drugs including their combinations are presented.
Kato expansion in quantum canonical perturbation theory
A. S. Nikolaev
Physics , 2015,
Abstract: This work establishes a connection between canonical perturbation series in quantum mechanics and a Kato expansion for the resolvent of the Liouville superoperator. Our approach leads to an explicit expression for a generator of a block-diagonalizing Dyson's ordered exponential in arbitrary perturbation order. Unitary intertwining of perturbed and unperturbed averaging superprojectors allows for a description of ambiguities in the generator and block-diagonalized Hamiltonian. We compare the efficiency of the corresponding computational algorithm with the efficiencies of the Van Vleck and Magnus methods for high perturbative orders.
Low-lying energy spectrum of the cerium dimer
A. V. Nikolaev
Physics , 2011, DOI: 10.1103/PhysRevA.84.012512
Abstract: The electronic structure of Ce2 is studied in a valence bond model with two 4f electrons localized at two cerium sites. It is shown that the low-lying energy spectrum of the simplest cerium chemical bond is determined by peculiarities of the occupied 4f states. The model allows for an analytical solution which is discussed along with the numerical analysis. The energy spectrum is a result of the interplay between the 4f valence bond exchange, the 4f Coulomb repulsion and the spin-orbit coupling. The calculated ground state is the even \Omega=\Lambda=\Sigma=0 level, the lowest excitations situated at 30 K are the odd \Omega=\Lambda=\Sigma=0 state and the $^{3} 6_5$ doublet (\Omega=\pm5,\, \Lambda=\pm6,\, \Sigma=\mp1). The calculated magnetic susceptibility displays different behavior at high and low temperatures. In the absence of the spin-orbit coupling the ground state is the ${}^3 \Sigma_g^-$ triplet. The results are compared with other many-electron calculations and experimental data.
Empirical Normalization for Quadratic Discriminant Analysis and Classifying Cancer Subtypes
Mark A. Kon,Nikolay Nikolaev
Statistics , 2012, DOI: 10.1109/ICMLA.2011.160
Abstract: We introduce a new discriminant analysis method (Empirical Discriminant Analysis or EDA) for binary classification in machine learning. Given a dataset of feature vectors, this method defines an empirical feature map transforming the training and test data into new data with components having Gaussian empirical distributions. This map is an empirical version of the Gaussian copula used in probability and mathematical finance. The purpose is to form a feature mapped dataset as close as possible to Gaussian, after which standard quadratic discriminants can be used for classification. We discuss this method in general, and apply it to some datasets in computational biology.
On stationary solutions of KdV and mKdV equations
A. V. Faminskii,A. A. Nikolaev
Mathematics , 2015,
Abstract: Stationary solutions on a bounded interval for an initial-boundary value problem to Korteweg--de~Vries and modified Korteweg--de~Vries equation (for the last one both in focusing and defocusing cases) are constructed. The method of the study is based on the theory of conservative systems with one degree of freedom. The obtained solutions turn out to be periodic. Exact relations between the length of the interval and coefficients of the equations which are necessary and sufficient for existence of nontrivial solutions are established.
Arterial hypertension associated with somatic pathology in present-day practice of internal diseases  [PDF]
Yurii A. Nikolaev, Igor M. Mitrofanov, Vladimir Ya. Polyakov, Nina. A. Dolgova
Health (Health) , 2014, DOI: 10.4236/health.2014.61015
Abstract: Dynamics of regional and gender features of occurrence of arterial hypertension associated with diseases of gallbladder, biliary ducts and pancreas for 2003-2011 was analyzed. There researched 23,310 patients (9111 males and 14,188 females) treated in clinic of scientific centre of clinical and experimental medicine SB RAMS. Occurrence of such combination, depending on gender, residence (the Novosibirsk region (NR) or Yakutia) as well as in age subgroups (16-39, 40-59 and over 60) was estimated. Occurrence of arterial hypertension associated with diseases of gallbladder, biliary ducts and pancreas was observed more in male of Subgroup I, living in NR and Yakutia. In 2003-2008 in female of Subgroup III, living in NR comorbidity pathology was observed more frequently than in male. In Subgroup III in female of NR occurrence of combined pathology was maximum (36.6%) 2006-2008, in female of Yakutia38.5% in 2003-2005. Dependence of occurrence of combined pathology on residence was observed in male. In 2003-2011 in male of Yakutia combined pathology was observed frequently than in male of NR. Occurrence of comorbidity pathology, depending on gender and age was typical for inhabitants of NR. In Group I comorbidity pathology was frequently observed in male, in Group IIIin female. It is necessary to develop regional strategies for observing patients with combined pathologies to improve prevention, rehabilitation and treatment of patients with arterial hypertension associated with diseases of gallbladder, biliary ducts and pancreas.
Monte-Carlo study of the phase transition in the AA-stacked bilayer graphene
A. A. Nikolaev,M. V. Ulybyshev
Physics , 2014,
Abstract: Tight-binding model of the AA-stacked bilayer graphene with screened electron-electron interactions has been studied using the Hybrid Monte Carlo simulations on the original double-layer hexagonal lattice. Instantaneous screened Coulomb potential is taken into account using Hubbard-Stratonovich transformation. G-type antiferromagnetic ordering has been studied and the phase transition with spontaneous generation of the mass gap has been observed. Dependence of the antiferromagnetic condensate on the on-site electron-electron interaction is examined.
Puzzle of the gamma-alpha and other phase transitions in cerium
A. V. Nikolaev,A. V. Tsvyashchenko
Physics , 2012, DOI: 10.3367/UFNe.0182.201207b.0701
Abstract: We discuss recent research on the phase transitions in cerium under pressure, including new experiments on the gamma-alpha transition, which indicate that it is a hidden structural phase transition.
Selective hydrogenation of phenylacetylene on gold nanoparticles
S. A. Nikolaev,V. V. Smirnov
Gold Bulletin , 2009, DOI: 10.1007/BF03214932
Abstract: This work investigates 2.5 – 30 nm gold nanoparticles immobilized on Al2O3. It shows that they possess high activity and stability in selective hydrogenation of phenylacetylene into styrene from a phenylacetylene-styrene mixture at 423 K. Strong dependences of the activity and selectivity of Au/ Al2O3 on the gold size were revealed: as the size of supported gold nanoparticles was decreased from 30 to 2.5 nm, the TOF of phenylacetylene hydrogenation increased from 0.028 to 0.142 s 1 and the selectivity of styrene formation increased by an order of magnitude. The nature of the identified dependences is discussed in terms of “Geometric” and “Electronic” size-effect points.
Theory of Distinct Crystal Structures of Polymerized Fullerides AC60, A=K, Rb, Cs: the Specific Role of Alkalis
K. H. Michel,A. V. Nikolaev
Physics , 2000, DOI: 10.1103/PhysRevLett.85.3197
Abstract: The polymer phases of AC60 form distinct crystal structures characterized by the mutual orientations of the (C60-)n chains. We show that the direct electric quadrupole interaction between chains always favors the orthorhombic structure Pmnn with alternating chain orientations. However the specific quadrupolar polarizability of the alkali metal ions leads to an indirect interchain coupling which favors the monoclinic structure I2/m with equal chain orientations. The competition between direct and indirect interactions explains the structural difference between KC60 and RbC60, CsC60.
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