369 research outputs found
Particularities of gastroduodenal pathology in children, associated with cytotoxic CAGA-positive strains of Helicobacter pylori.
The aim of the study was to investigate the characteristics of inflammatory gastroduodenal diseases in children, associated with CagA-positive strains of H. pylori. We observed 283 children aged 7 to 17 years with chronic gastroduodenal pathology in exacerbation stage; endoscopic examination of the esophagus, stomach and duodenum was performed, total Ig M, A, G to Ag SagA H. pylori protein in blood serum by ELISA was determined. The study group included 156 patients infected with cytotoxic CagA (+) strains of H. pylori (H. pylori-positive status), comparison group - 59 (20,9%) patients with H. pylori-negative status. It was shown that 55.1% of patients observed were infected with cytotoxic CagA (+) strains of H. pylori. The intensity of clinical symptoms and the severity of inflammatory changes in stomach and duodenum mucosa in children with H. pylori infection is associated with cytotoxic strains of CAG A H. pylori. Presence of extensive gastritis (34,6%; p<0,05), lymphoid hyperplasia (16,0%; p <0,05), turbid mucus in the gastric lumen are the special features of endoscopic changes in children with H. pylori-positive status
Development of the Metal Rheology Model of High-temperature Deformation for Modeling by Finite Element Method
It is shown that when modeling the processes of forging and stamping, it is necessary to take into account not only the hardening of the material, but also softening, which occurs during hot processing. Otherwise, the power parameters of the deformation processes are precisely determined, which leads to the choice of more powerful equipment. Softening accounting (processes of stress relaxation) will allow to accurately determine the stress and strain state (SSS) of the workpiece, as well as the power parameters of the processes of deformation. This will expand the technological capabilities of these processes. Existing commercial software systems for modeling hot plastic deformations based on the finite element method (FEM) do not allow this. This is due to the absence in these software products of the communication model of the component deformation rates and stresses, which would take into account stress relaxation. As a result, on the basis of the Maxwell visco-elastic model, a relationship is established between deformation rates and stresses. The developed model allows to take into account the metal softening during a pause after hot deformation. The resulting mathematical model is tested by experiment on different steels at different temperatures of deformation. The process of steels softening is determined using plastometers. It is established experimentally that the model developed by 89 ... 93 % describes the rheology of the metal during hot deformation. The relationship between the components of the deformation rates and stresses is established, which allows to obtain a direct numerical solution of plastic deformation problems without FED iterative procedures, taking into account the real properties of the metal during deformation. As a result, the number of iterations and calculations has significantly decreased
От идеи к синтезу модели образовательного стандарта подготовки ученых в аспирантуре
In a Quintessence form an idea and sequence is considered the synthesized decision of paradoxical problems in the system of preparation of research and scientifically-pedagogical workers of higher qualification.В квинтэссентной форме рассмотрено идею и последовательность синтезированного решения парадоксальных проблем в системе подготовки научных и научно-педагогических работников высшей квалификации
Methodological aspects of monitoring implementation in public sector organizations
In this paper the monitoring implementation is considered in systemic and process approaches, in these approaches monitoring is integrated into controlling and planning functions, respectively. It was proved that for indicative management integration with organizing function is required. This statement is based on monitoring place in the overall indicative management system and its methodological basi
Quantum Kinetic Evolution of Marginal Observables
We develop a rigorous formalism for the description of the evolution of
observables of quantum systems of particles in the mean-field scaling limit.
The corresponding asymptotics of a solution of the initial-value problem of the
dual quantum BBGKY hierarchy is constructed. Moreover, links of the evolution
of marginal observables and the evolution of quantum states described in terms
of a one-particle marginal density operator are established. Such approach
gives the alternative description of the kinetic evolution of quantum
many-particle systems to generally accepted approach on basis of kinetic
equations.Comment: 18 page
The von Neumann Hierarchy for Correlation Operators of Quantum Many-Particle Systems
The Cauchy problem for the von Neumann hierarchy of nonlinear equations is
investigated. One describes the evolution of all possible states of quantum
many-particle systems by the correlation operators. A solution of such
nonlinear equations is constructed in the form of an expansion over particle
clusters whose evolution is described by the corresponding order cumulant
(semi-invariant) of evolution operators for the von Neumann equations. For the
initial data from the space of sequences of trace class operators the existence
of a strong and a weak solution of the Cauchy problem is proved. We discuss the
relationships of this solution both with the -particle statistical
operators, which are solutions of the BBGKY hierarchy, and with the
-particle correlation operators of quantum systems.Comment: 26 page
On the solutions of the nonlinear Liouville hierarchy
We investigate the initial-value problem of the non-linear Liouville
hierarchy. For the general form of the interaction potential we construct an
explicit solution in terms of an expansion over particle clusters whose
evolution is described by the corresponding-order cumulant of evolution
operators of a system of finitely many particles. For the initial data from the
space of integrable functions the existence of a strong solution of the Cauchy
problem is proved.Comment: 9 page
Towards Rigorous Derivation of Quantum Kinetic Equations
We develop a rigorous formalism for the description of the evolution of
states of quantum many-particle systems in terms of a one-particle density
operator. For initial states which are specified in terms of a one-particle
density operator the equivalence of the description of the evolution of quantum
many-particle states by the Cauchy problem of the quantum BBGKY hierarchy and
by the Cauchy problem of the generalized quantum kinetic equation together with
a sequence of explicitly defined functionals of a solution of stated kinetic
equation is established in the space of trace class operators. The links of the
specific quantum kinetic equations with the generalized quantum kinetic
equation are discussed.Comment: 25 page
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