Робастное управление нелинейной системой

Now a theory basis robust managements make analysis methods robust stability and robust stabilization of linear objects. One set linear system, and stability of the whole family of the systems corresponding to initial (nominal) system in the presence of uncertainty is thus investigated not. Management problems, as a rule, are reduced to stabilization or optimum control problems at not set time of the termination of transient. It allows to use the frequency methods developed in the theory of automatic control [1]. Use of these methods for synthesis of operating influences for non-stationary nonlinear systems is impossible. In work optimum control for robust nonlinear system on the first approach is synthesized. There are living conditions of stabilizing management.В настоящее время основу теории робастного управления составляют методы анализа робастной устойчивости и робастной стабилизации линейных объектов. Исследуется не одна заданная линейная система, а устойчивость целого семейства систем, соответствующих исходной (номинальной) системе при наличии неопределенности. Задачи управления, как правило, сводятся к задачам стабилизации или оптимального управления при незаданном времени окончания переходного процесса. Это позволяет использовать частотные методы, разработанные в теории автоматического регулирования [1]. Использование этих методов для синтеза управляющих воздействий для нестационарных нелинейных систем невозможно. В работе синтезируется оптимальное управление для робастной нелинейной системы по первому приближению. Находятся условия существования стабилизирующего управления

Software Development to Assess the Dynamics of Stented Heart Vessel Rest enosis for ARM-Cardiologist

The article considered the database and the software developed on the basis of the authors' team previous studies devoted to the evaluation of restenosis dynamics of the stented heart vessels. This software is the part of ARM-Cardiologis

РЕЗУЛЬТАТЫ ПРИМЕНЕНИЯ ФОСФОМИЦИНА ДЛЯ ИМПРЕГНАЦИИ ОСТЕОЗАМЕЩАЮЩИХ МАТЕРИАЛОВ ПРИ ЛЕЧЕНИИ ХРОНИЧЕСКОГО ОСТЕОМИЕЛИТА

Aim – to evaluate in the experimental study in vitro the duration of antimicrobial activity of fosfomycin-impregnated bone cement and to study the dynamics of radiological and morphological changes depending on the local antibiotic therapy in two-stage treatment of chronic osteomyelitis in rabbits.Materials and methods. Duration of antimicrobial activity of bone cement (depuy cmw1 gentamicin) with fosfomycin in vitro was studied in comparison to cements with vancomycin and controls without additional antibiotics. Presence of the lysis zone of bacterial cultures was evaluated (Staphylococcus aureus ATCC6538 and ATCC33591, Klebsiella pneumoniae ATCC33495 and Escherichia coli ATCC25922) after application of 10 μl of the solution, collected from the cement samples after incubation for 24 hours. For the in vivo experiment, Chinchilla rabbits (n = 20) with local osteomyelitis of the tibia underwent two-stage treatment where substitution of the bone defect at stage I was performed with PMMA and stage II – with the bioresorbable material based on hydroxyapatite and triclacium phosphate (ReproBone). In an experience group (n = 10) before setting osteoreplacement materials with fosfomycin (group FOSFO), and by control (n = 10) – vancomycin (group VANCO). X-ray imaging was performed on the 1st and 21st day after installation of the cement spacer, and 45th day after substitution of the spacer with the bioresorbable material. Microbiological analysis of the samples was performed intraoperatively and on the 7th, 14th day after each stage. Histological study was conducted in both groups on the 14th, 21th day after stage I and 45th day after stage II of the treatment.Results. Maximal duration of antimicrobial activity in vitro was observed in samples of PMMA with fosfomycin whereas minimal – in control samples of gentamicin-based bone cement. Relief of the infection was attained in all animals while application of fosfomycin resulted in a more rapid elimination of the bacteria. Reaction of the adjacent tissue to the implanted material and results of X-ray imaging in both groups did not differ significantly. Long duration of the broad-spectrum antimicrobial activity of the bone cement with fosfomycin with the comparable perifocal reaction in vivo necessitates further study of the use of this antibiotic in bioresorbable materials for the treatment of osteomyelitis in clinical practice.Цель – оценить в эксперименте in vitro длительность антимикробной активности образцов импрегнированного фосфомицином костного цемента и изучить динамику рентгенологической и морфологической картины в зависимости от локальной антибактериальной терапии при двухэтапном лечении хронического остеомиелита у кроликов.Материал и методы. Изучали in vitro длительность антимикробной активности образцов импрегнированного фосфомицином костного цемента (depuy cmw1 gentamicin) в сравнении с импрегнацией ванкомицином и контрольными образцами без внесения дополнительного антибиотика. Оценивали наличие зоны лизиса бактериальной культуры (Staphylococcus aureus ATCC6538 и ATCC33591, Klebsiella pneumoniae ATCC33495 и Escherichia coli ATCC25922) в области нанесения 10 мкл инкубационного раствора после инкубации образца в течение 24 час. В эксперименте in vivo 20 кроликам породы Шиншилла c локальным очагом остеомиелита большеберцовой кости проводили двухэтапное лечение. На первом этапе костный дефект замещали костным цементом на основе полиметилметакрилата (ПММА), на втором этапе – биорезорбируемым материалом на основе гидроксиапатита и трикальцийфосфата (ReproBone). В опытной группе (n = 10) перед установкой остеозамещающие материалы импрегнировали фосфомицином (группа ФОСФО), а в контрольной группе (n = 10) – ванкомицином (группа ВАНКО). Рентгенологические исследования выполняли в первые и 21-е сутки после установки цементного спейсера, на 45-е сутки после удаления цементного спейсера и укладки биорезорбируемого материала. Бактериологические исследования выполняли интраоперационно, на 7-е и 14-е сутки после каждого этапа. Морфологические исследования выполняли в обеих группах на 14-е и 21-е сутки после первого этапа и на 45-е сутки после второго этапа лечения.Результаты. Максимальная продолжительность антимикробной активности in vitro установлена при использовании ПММА с фосфомицином, минимальная – для контрольных образцов из официнального гентамицин-содержащего цемента. В эксперименте in vivo у всех животных было достигнуто купирование инфекционного процесса, однако применение фосфомицина приводило к более быстрой эрадикации возбудителя. Реакции тканей, окружающих имплантированный материал, в обеих группах экспериментальных животных различались незначительно, рентгенологическая картина была схожей. Большая длительность антимикробного действия образцов костного цемента с фосфомицином в отношении широкого спектра возбудителей при сопоставимых перифокальных реакциях в эксперименте in vivo делает перспективным дальнейшее изучение данного антибиотика в составе остеозамещающих материалов при лечении остеомиелита в клинической практике

Cherenkov radiation emitted by ultrafast laser pulses and the generation of coherent polaritons

We report on the generation of coherent phonon polaritons in ZnTe, GaP and LiTaO$_{3}$ using ultrafast optical pulses. These polaritons are coupled modes consisting of mostly far-infrared radiation and a small phonon component, which are excited through nonlinear optical processes involving the Raman and the second-order susceptibilities (difference frequency generation). We probe their associated hybrid vibrational-electric field, in the THz range, by electro-optic sampling methods. The measured field patterns agree very well with calculations for the field due to a distribution of dipoles that follows the shape and moves with the group velocity of the optical pulses. For a tightly focused pulse, the pattern is identical to that of classical Cherenkov radiation by a moving dipole. Results for other shapes and, in particular, for the planar and transient-grating geometries, are accounted for by a convolution of the Cherenkov field due to a point dipole with the function describing the slowly-varying intensity of the pulse. Hence, polariton fields resulting from pulses of arbitrary shape can be described quantitatively in terms of expressions for the Cherenkov radiation emitted by an extended source. Using the Cherenkov approach, we recover the phase-matching conditions that lead to the selection of specific polariton wavevectors in the planar and transient grating geometry as well as the Cherenkov angle itself. The formalism can be easily extended to media exhibiting dispersion in the THz range. Calculations and experimental data for point-like and planar sources reveal significant differences between the so-called superluminal and subluminal cases where the group velocity of the optical pulses is, respectively, above and below the highest phase velocity in the infrared.Comment: 13 pages, 11 figure

Phi meson production in Au+Au and p+p collisions at sqrt (s)=200 GeV

We report the STAR measurement of Phi meson production in Au+Au and p+p collisions at sqrt (s)=200 GeV. Using the event mixing technique, the Phi spectra and yields are obtained at mid-rapidity for five centrality bins in Au+Au collisions and for non-singly-diffractive p+p collisions. It is found that the Phi transverse momentum distributions from Au+Au collisions are better fitted with a single-exponential while the p+p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that Phi production in central Au+Au collisions is suppressed relative to peripheral collisions when scaled by the number of binary collisions. The systematics of versus centrality and the constant Phi/K- ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for Phi production.Comment: 6 pages, 3 figures, submitted to Phys. Rev. Let

Kaon Production and Kaon to Pion Ratio in Au+Au Collisions at \snn=130 GeV

Mid-rapidity transverse mass spectra and multiplicity densities of charged and neutral kaons are reported for Au+Au collisions at \snn=130 GeV at RHIC. The spectra are exponential in transverse mass, with an inverse slope of about 280 MeV in central collisions. The multiplicity densities for these particles scale with the negative hadron pseudo-rapidity density. The charged kaon to pion ratios are $K^+/\pi^- = 0.161 \pm 0.002 {\rm (stat)} \pm 0.024 {\rm (syst)}$ and $K^-/\pi^- = 0.146 \pm 0.002 {\rm (stat)} \pm 0.022 {\rm (syst)}$ for the most central collisions. The $K^+/\pi^-$ ratio is lower than the same ratio observed at the SPS while the $K^-/\pi^-$ is higher than the SPS result. Both ratios are enhanced by about 50% relative to p+p and $\bar{\rm p}$+p collision data at similar energies.Comment: 6 pages, 3 figures, 1 tabl

Energy and system size dependence of \phi meson production in Cu+Cu and Au+Au collisions

We study the beam-energy and system-size dependence of \phi meson production (using the hadronic decay mode \phi -- K+K-) by comparing the new results from Cu+Cu collisions and previously reported Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV measured in the STAR experiment at RHIC. Data presented are from mid-rapidity (|y|<0.5) for 0.4 < pT < 5 GeV/c. At a given beam energy, the transverse momentum distributions for \phi mesons are observed to be similar in yield and shape for Cu+Cu and Au+Au colliding systems with similar average numbers of participating nucleons. The \phi meson yields in nucleus-nucleus collisions, normalised by the average number of participating nucleons, are found to be enhanced relative to those from p+p collisions with a different trend compared to strange baryons. The enhancement for \phi mesons is observed to be higher at \sqrt{s_NN} = 200 GeV compared to 62.4 GeV. These observations for the produced \phi(s\bar{s}) mesons clearly suggest that, at these collision energies, the source of enhancement of strange hadrons is related to the formation of a dense partonic medium in high energy nucleus-nucleus collisions and cannot be alone due to canonical suppression of their production in smaller systems.Comment: 20 pages and 5 figure

Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration

Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (p_T), elliptic flow, two-particle correlations, non-statistical fluctuations, and suppression of particle production at high p_T. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted to Nuclear Physics A as a regular article; v3 has minor changes in response to referee comments. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Creation of the precision magnetic spectrometer SCAN-3

The new JINR project [1] is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article

Measurement of the t-channel single top quark production cross section in pp collisions at √s =7 TeV

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