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Search Results: 1 - 10 of 135537 matches for " Igor V. Sergienko "
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Identification of Patients at High Cardiovascular Risk
Igor V. Sergienko, PhD, ScD,Saule J. Urazalina, PhD,Valery V. Kukharchuk, PhD, ScD,Yuri A. Karpov, PhD, ScD
International Journal of BioMedicine , 2012,
Abstract: Objective: To identify individuals at high cardiovascular risk (CVR) to check for an additional estimate of CVR with the use of the ESH/ESC Guidelines (2003, 2007) in patients earlier classified as being at low and moderate risk on SCORE . Material and methods: The study included 600 people (155 men and 445 women) with low and moderate cardiovascular risk on the SCORE scale. All patients were examined with duplex scanning of the carotid arteries (DSCA) to the determined of the thickness of the intima – media (IMT), the presence of atherosclerotic plaques (ASP); it has also been performed sphygmographic computer (SC) with automatic estimation of brachial-ankle pulse wave velocity (baPWV), biochemical analysis of blood lipid spectrum. Results: The frequency of ASP was 59.5% (357 out of 600), and a thickening of thecomplex "intima-media" (IMT)> 0.9 mm was detected in only 5% of the cases (28 persons out of 600), that indicated a slight contribution to the magnitude of the risk of such parameters as the IMT. The total number of patients with signs of preclinicallesions of the arterial wall (the presence of ASP and/or increased baPWV) was 337 (56% of 600). Our results showed that the presence of subclinical atherosclerosis is in itself a risk factor. Conclusion: The usage of instrumental methods of research (DSCA, SC) allowed to detect 32% of individuals with high CVR from 600 previously classified as low and moderate risk on SCORE scale. In our opinion, the proposed algorithm is convenient and easy to use for transfer of the patients into high-risk group.
Synthesis, characterization, spectroscopic and crystallographic investigation of metal complexes of N-benzyl-N-nitrosohydroxylamine  [PDF]
Olga Kovalchukova, Ali Sheikh Bostanabad, Vladimir Sergienko, Irina Polyakova, Igor Zyuzin, Svetlana Strashnova
Open Journal of Inorganic Chemistry (OJIC) , 2013, DOI: 10.4236/ojic.2013.31001
Abstract:

New metal complexes of N-benzyl-N-nitrosohy-droxylamine (BNHA) are isolated and characterized by elemental analysis, IR and UV-VIS spectroscopy. Spectrophotometric titration of aqueous solutions of BNHА by salts of some transition metals allowed to calculate the composition and formation constants of the metal complexes. The crystal structure of Cu (BNHА)2 is studied by X-ray diffraction. The Cu atom is coordinated by four O atoms of two bidentate ligands, which close 5-membered chelate rings. The N-O (1.306 ? - 1.320 ?) and N-N (1.274 ? and 1.275? ) bond lengths indicate that π electrons are delocalized over the chelating groups. Complexes form stacks with intermolecular Cu…N contacts equal to 3.118 ? and 3.306 ?.

General Patterns of Spatial Distribution of the Integral Characteristics of Benthic Macrofauna of the Northwestern Pacific and Biological Structure of Ocean  [PDF]
Igor V. Volvenko
Open Journal of Ecology (OJE) , 2014, DOI: 10.4236/oje.2014.44020
Abstract:

Horizontal (geographic) and vertical (geonemic) spatial distribution of the integral properties of a large multispecies assemblage (1306 species of fish and invertebrate with body size ≥ 1 cm) from northwest Pacific sea bottom is investigated. There are total number and biomass, average animal size (mean individual weight), species diversity (Shannon’s index) and its components: species richness and evenness (Pielou’s index), i.e. generalized parameters describing benthic macrofauna as a whole. Correlations of these parameters with distance from shore and depth have been found as well as very weak latitudinal zonality display in the region. Even such well-known generalization as Humboldt-Wallace’s law and Bergman’s rule has no noticeable manifestations here. Earlier similar, but not identical, regularities were discovered in the northwest Pacific pelagic water layer. Collation of what there is in the two different sea zones results in new supplements to Zenkevich-Bogorov’s concept of biological structure of the ocean.

Multimoment Hydrodynamics in Problem on Flow around a Sphere: Entropy Interpretation of the Appearance and Development of Instability  [PDF]
Igor V. Lebed
Open Journal of Fluid Dynamics (OJFD) , 2014, DOI: 10.4236/ojfd.2014.42015
Abstract:

Multimoment hydrodynamics equations are applied to investigate the phenomena of appearance and development of instability in problem on a flow around a solid sphere at rest. The simplest solution to the multimoment hydrodynamics equations coincides with the Stokes solution to the classic hydrodynamics equations in the limit of small Reynolds number values, . Solution  to the multimoment hydrodynamics equations reproduces recirculating zone in the wake behind the sphere having the form of an axisymmetric toroidal vortex ring. The  solution remains stable while the entropy production in the system exceeds the entropy outflow through the surface confining the system. The passage of the first critical value  is accompanied by the  solution stability loss. The  solution, when loses its stability, reproduces periodic pulsations of the periphery of the recirculating zone in the wake behind the sphere. The  and  solutions to the multimoment hydrodynamics equations interpret a vortex shedding. After the second critical value  is reached, the  solution at the periphery of the recirculating zone and in the far wake is replaced by the  solution. In accordance with the  solution, the periphery of the recirculating zone periodically detached from the core and moves downstream in the form of a vortex ring. After the attainment of the third critical value , the  solution at the periphery of the recirculating zone and in the far wake is replaced by the  solution. In accordance with the  solution, vortex rings penetrate into each other and form the continuous vortex sheet in the wake behind the sphere. The replacement of one unstable flow regime by another unstable regime is governed the tendency of the system to discover the fastest path to depart from the state of statistical equilibrium. Having lost the stability, the system does not reach a new stable position. Such a scenario differs from the ideas of classic hydrodynamics, which interprets the development of instability in terms of bifurcations from one stable state to another stable state. Solutions to the multimoment hydrodynamics equations indicate the direction of instability development, which qualitatively reproduces the experimental data in a wide range of Re values. The problems encountered by classic hydrodynamics when interpreting the observed instability development process are solved on the way toward an increase in the number of principle hydrodynamic values.

About Appearance of the Irreversibility  [PDF]
Igor V. Lebed
Open Journal of Fluid Dynamics (OJFD) , 2014, DOI: 10.4236/ojfd.2014.43023
Abstract: The inevitability of arising in equations of kinetics and hydrodynamics irreversibility not contained in original equations of classic mechanics is substantiated. It is established that transfer of information about the direction of system evolution from initial conditions to resulting equations is the consequence of losing information about the position of an individual particle in space, which takes place at roughening description. It is shown that the roughening with respect to impact parameters of colliding particles is responsible for appearance of the irreversibility in resulting equations. Direct equations of kinetics and hydrodynamics are the result of roughening distribution functions with respect to impact parameters of particles, which have not yet reached the domain of their interaction. The direct equations are valid for the progressive direction of timing on the time axis pointing from the past to the future. Reverse equations of kinetics and hydrodynamics are the result of roughening distribution functions with respect to impact parameters of particles, which have already left the domain of their interaction. The reverse equations are valid for the progressive direction of timing on the time axis pointing from the future to the past.
Kinetic Foundation for the Multimoment Hydrodynamics Equations  [PDF]
Igor V. Lebed
Open Journal of Fluid Dynamics (OJFD) , 2015, DOI: 10.4236/ojfd.2015.51010
Abstract: The equations for the pair distribution functions are derived directly from the second equation of the Bogolyubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy. The derivation is fulfilled within the frameworks of the multiscale method. The equations for the pair distribution functions are the kinetic foundation for the multimoment hydrodynamics equations. Solutions to the equations for the pair distribution functions predetermine the possibility of constructing the hydrodynamics equations with an arbitrary number of principle hydrodynamic values specified beforehand. The tendency to increase the number of principal hydrodynamic values is caused by the necessity of interpreting the behavior of the system after the loss of stability. Solutions to the classic hydrodynamics equations constructed for only three principle hydrodynamic values are unable to predict the direction of instability evolution. Solutions to the multimoment hydrodynamics equations are capable of reproducing correctly the phenomenon of emergence and development of instability.
The Concept of Information Support for Bi-oresource and Ecosystem Research in the North-West Pacific: Theory and Practical Implementation  [PDF]
Igor V. Volvenko
Natural Resources (NR) , 2016, DOI: 10.4236/nr.2016.71004
Abstract: The first part of the article provides an overview of the theoretical evidence, the main provisions, and the implementation strategy of information support for bioresource and ecosystem research in the north-west Pacific, which has been conducted over the past 20 years in the Russian Far East Research Institute TINRO-Center. In short, the concept consists of a combination of the following four assertions: 1) For the steady and sustainable development of the Russian Far East, the entire Russian Federation and the Asia-Pacific Region in general, environmental, food, economic, and other security is required, which cannot be achieved without the rational use of bioresources based on the ecosystem approach to the management of aquatic bioresources. 2) For the inventory, appraisal, monitoring, forecasting of the state of and management the natural water resources when applying this approach, statistically relevant quantitative information is required on the greatest possible number of constituents of marine biocenosis of the north-western Pacific for the longest possible period of time, which is only available at the TINRO-Center. 3) This valuable data should be organized into databases, based on which geo-information and other electronic information systems are prepared, and based on these map atlases and reference books on natural water resources, using automated workplaces created especially for this. 4) The resulting unique information support will be of great value not only for practical purposes, but also for science, both applied and fundamental. Next comes a summary of the many years of work on the practical implementation of this concept and the key achievements in this field obtained by the TINRO-Center by the end of 2015 are reviewed. At the end, some plans for the near future are outlined.
Data assimilation using a hybrid ice flow model
D. N. Goldberg,O. V. Sergienko
The Cryosphere , 2011, DOI: 10.5194/tc-5-315-2011
Abstract: Hybrid models, or depth-integrated flow models that include the effect of both longitudinal stresses and vertical shearing, are becoming more prevalent in dynamical ice modeling. Under a wide range of conditions they closely approximate the well-known First Order stress balance, yet are of computationally lower dimension, and thus require less intensive resources. Concomitant with the development and use of these models is the need to perform inversions of observed data. Here, an inverse control method is extended to use a hybrid flow model as a forward model. We derive an adjoint of a hybrid model and use it for inversion of ice-stream basal traction from observed surface velocities. A novel aspect of the adjoint derivation is a retention of non-linearities in Glen's flow law. Experiments show that in some cases, including those nonlinearities is advantageous in minimization of the cost function, yielding a more efficient inversion procedure.
Data assimilation using a hybrid ice flow model
D. N. Goldberg,O. V. Sergienko
The Cryosphere Discussions , 2010, DOI: 10.5194/tcd-4-2201-2010
Abstract: Hybrid models, or depth-integrated flow models that include the effect of both longitudinal stresses and vertical shearing, are becoming more prevalent in dynamical ice modeling. Under a wide range of conditions they closely approximate the well-known First Order stress balance, yet are of computationally lower dimension, and thus require less intensive resources. Concomitant with the development and use of these models is the need to perform inversions of observed data. Here, an inverse control method is extended to use a hybrid flow model as a forward model. We derive an adjoint of a hybrid model and use it for inversion of ice-stream basal traction from observed surface velocities. A novel aspect of the adjoint derivation is a retention of non-linearities in Glen's flow law. Experiments show that including those nonlinearities is advantageous in minimization of the cost function, yielding a more efficient inversion procedure.
Spatial-Dispersion Cancellation in Quantum Interferometry
D. S. Simon,A. V. Sergienko
Physics , 2009, DOI: 10.1103/PhysRevA.80.053813
Abstract: We investigate cancellation of spatial aberrations induced by an object placed in a quantum coincidence interferometer with type-II parametric down conversion as a light source. We analyze in detail the physical mechanism by which the cancellation occurs, and show that the aberration cancels only when the object resides in one particular plane within the apparatus. In addition, we show that for a special case of the apparatus it is possible to produce simultaneous cancellation of both even-order and odd-order aberrations in this plane.
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