Self-Organized States in Cellular Automata: Exact Solution

The spatial structure, fluctuations as well as all state probabilities of self-organized (steady) states of cellular automata can be found (almost) exactly and {\em explicitly} from their Markovian dynamics. The method is shown on an example of a natural sand pile model with a gradient threshold.Comment: 4 pages (REVTeX), incl. 2 figures (PostScript

Infinite volume limit of the Abelian sandpile model in dimensions d >= 3

We study the Abelian sandpile model on Z^d. In dimensions at least 3 we prove existence of the infinite volume addition operator, almost surely with respect to the infinite volume limit mu of the uniform measures on recurrent configurations. We prove the existence of a Markov process with stationary measure mu, and study ergodic properties of this process. The main techniques we use are a connection between the statistics of waves and uniform two-component spanning trees and results on the uniform spanning tree measure on Z^d.Comment: First version: LaTeX; 29 pages. Revised version: LaTeX; 29 pages. The main result of the paper has been extended to all dimensions at least 3, with a new and simplyfied proof of finiteness of the two-component spanning tree. Second revision: LaTeX; 32 page

Abelian Sandpile Model on the Honeycomb Lattice

We check the universality properties of the two-dimensional Abelian sandpile model by computing some of its properties on the honeycomb lattice. Exact expressions for unit height correlation functions in presence of boundaries and for different boundary conditions are derived. Also, we study the statistics of the boundaries of avalanche waves by using the theory of SLE and suggest that these curves are conformally invariant and described by SLE2.Comment: 24 pages, 5 figure

Fine Structure of Avalanches in the Abelian Sandpile Model

We study the two-dimensional Abelian Sandpile Model on a square lattice of linear size L. We introduce the notion of avalanche's fine structure and compare the behavior of avalanches and waves of toppling. We show that according to the degree of complexity in the fine structure of avalanches, which is a direct consequence of the intricate superposition of the boundaries of successive waves, avalanches fall into two different categories. We propose scaling ans\"{a}tz for these avalanche types and verify them numerically. We find that while the first type of avalanches has a simple scaling behavior, the second (complex) type is characterized by an avalanche-size dependent scaling exponent. This provides a framework within which one can understand the failure of a consistent scaling behavior in this model.Comment: 10 page

Neutron and synchrotron X-ray powder study of copper(II) chloride complex with deuterated 1-ethyltetrazole

The structure of the copper(II) chloride complex with deuterated 1-ethyltetrazole has been investigated in the temperature range of 2-290 K using neutron and synchrotron X-ray powder diffraction. The compound was found to exhibit structural transformation at ca 180 K, without change of space group and main structural motif. At higher temperatures, the complex reveals positional disorder of the ethyl group, whereas no disorder is observed at lower temperatures. Temperature dependence of the lattice parameters, obtained from synchrotron X-ray data, showed main lattice changes at the transformation, explained by structural features of the complex. From the magnetic measurements, the effect of the disorder on paramagnetic behaviour of the compound was found. Detailed structural data of the compound at 2 and 290 K, obtained from neutron powder diffraction data, are reported. © by Oldenbourg Wissenschaftsverlag, München

Комплексы противотуберкулезных антибиотиков с сульфатом-ацетатом целлюлозы

Water-insoluble complexes of antituberculosis antibiotics (AB) kanamycin (CNMC), amikacin (AMCC) and capreomycin (CPRMC), traditionally used parenterally, with cellulose acetate sulphate in the form of sodium salt (Na-SAC) were obtained. The possibility of their immobilization on the activated carbon (AC) to create a tablet form of AB was demonstrated. The composition of the complexes was determined depending on the medium pH and the order of solutions components mixing. It was shown that with decreasing pH from 6 to 1 due to an increase in the number of protonated amine groups in AB molecules, the number of contacts with polymer macromolecules increases and the amount of cellobiosic units in the complex’s composition increases as well: in the case of CNMC and AMCC from one to three and to four in the case of CPRMC. The electrostatic nature of the complexation is confirmed by the corresponding bands’ shifts in the IR spectra: Na-SAC sulfate groups and the antibiotic amino groups. It was established in vitro that the Na-SAC–CNMC complexes and their compositions with activated carbon are not only equivalent, but also have the double activity of the standard (injectable) form of CNMC in the relation to tuberculosis mycobacterium. The resulting compositions can be recommended for in vivo testing as a new form of aminoglycoside antibiotics for oral administration.Получены водонерастворимые полимерные комплексы противотуберкулезных антибиотиков (АБ) канамицина (КНМЦ), амикацина (АМКЦ) и капреомицина (КПРМЦ), традиционно применяемых парентерально, с сульфатом-ацетатом целлюлозы в форме натриевой соли (Na-САЦ). Показана возможность их иммобилизации на активированном угле (АУ) для создания таблетированной формы АБ. Определен состав комплексов в зависимости от рН среды и порядка смешения растворов компонентов. Показано, что с уменьшением рН от 6 до 1 вследствие увеличения числа протонированных аминогрупп в молекулах АБ увеличивается число контактов с макромолекулами полимера и количество целлобиозных звеньев, участвующих в образовании комплекса, возрастает: в случае КНМЦ и АМКЦ от одного до трех и до четырех в случае КПРМЦ. Электростатический характер комплексообразования подтвержден фактом смещения полос, принадлежащих сульфатным Na-САЦ и аминогруппам антибиотиков, в ИК-спектрах комплексов. Установлено in vitro, что комплекы Na-CAЦ–КНМЦ и их композиции с активированным углем превышают активность стандартной (инъекционной) формы КНМЦ в два раза по отношению к микобактериям туберкулеза. Полученные композиции можно рекомендовать для проведения испытаний in vivo в качестве новой формы аминогликозидных антибиотиков для перорального применения

AdS_3/LCFT_2 - Correlators in Cosmological Topologically Massive Gravity

For cosmological topologically massive gravity at the chiral point we calculate momentum space 2- and 3-point correlators of operators in the postulated dual CFT on the cylinder. These operators are sourced by the bulk and boundary gravitons. Our correlators are fully consistent with the proposal that cosmological topologically massive gravity at the chiral point is dual to a logarithmic CFT. In the process we give a complete classification of normalizable and non-normalizeable left, right and logarithmic solutions to the linearized equations of motion in global AdS_3.Comment: 39 pages + appendices, 1 eps figure, v2: minor changes in text in 4.1.2, corrected typo in (2.31

Absorbing-state phase transitions in fixed-energy sandpiles

We study sandpile models as closed systems, with conserved energy density $\zeta$ playing the role of an external parameter. The critical energy density, $\zeta_c$, marks a nonequilibrium phase transition between active and absorbing states. Several fixed-energy sandpiles are studied in extensive simulations of stationary and transient properties, as well as the dynamics of roughening in an interface-height representation. Our primary goal is to identify the universality classes of such models, in hopes of assessing the validity of two recently proposed approaches to sandpiles: a phenomenological continuum Langevin description with absorbing states, and a mapping to driven interface dynamics in random media. Our results strongly suggest that there are at least three distinct universality classes for sandpiles.Comment: 41 pages, 23 figure

Термические свойства композиционных волокон состава целлюлоза-хитозан

Cellulose-chitosan composite fibers were obtained by the method of wet spinning from joint solutions in phosphoric acid. Thermogravimetry (TG), differential thermogravimetry (DTG) and differential scanning calorimetry (DSC) methods have been used to evaluate their thermal properties in the range of 20-600 °C in air atmosphere. It was found that the temperature of the maximum decomposition rate of composite fibers lies between the temperatures characteristic of individual components. It is shown that the addition of chitosan to cellulose leads to an increase in the mass of the carbon residue and gives the cellulosic fibers a self-extinguishing property. The observed effect is explained by the uniform distribution of cellulose and chitosan macromolecules and their aggregates separated by interphase layers in each other, in which a net of interpenetrating segments of both polymer macromolecules is represented. This provides the incombustibility for composite fibers with a chitosan content of more than 20 % and maintaining the integrity of the fibers after processing them with a solvent of chitosan-acetic acid.Получены композиционные волокна состава целлюлоза-хитозан по способу мокрого формования из совместных растворов в ортофосфорной кислоте. Методами термогравиметрии (ТГ), дифференциальной термогравиметрии (ДТГ) и дифференциальной сканирующей калориметрии (ДСК) проведена оценка их термических свойств в интервале 20-600 оС в атмосфере воздуха. Установлено, что температура максимальной скорости разложения композиционных волокон лежит между температурами, характерными для индивидуальных компонентов. Показано, что добавление к целлюлозе хитозана приводит к росту массы карбонизованного остатка и придает целлюлозным волокнам свойство самозатухаемости. Дано объяснение наблюдаемому эффекту, обусловленному достижением равномерного распределения друг в друге макромолекул целлюлозы и хитозана и их агрегатов, разделенных межфазными слоями, в которых реализована сетка зацеплений взаимопроникающих сегментов макромолекул обоих полимеров, что обеспечивает появление у композиционных волокон негорючести при содержании хитозана более 20 % и сохранение целостности волокон после их обработки растворителем хитозана - уксусной кислотой

ПОЛИМЕРНЫЕ КОМПЛЕКСЫ ЦЕФАЛОСПОРИНОВЫХ АНТИБИОТИКОВ С СУЛЬФАТОМ АЦЕТАТОМ ЦЕЛЛЮЛОЗЫ

The state-of the-art in antibiotics modification is the development of acid resistant dosage forms for per oral treatment. This article is about the synthesis of complexes of ceftriaxone and cefotaxime, 3rd generation antibiotics of cephalosporines family, with new water-soluble cellulose derivative – acetate sulfate sodium salt. The composition of complexes was established by UV- and FTIR-spectroscopy. Stable in acid media tablet dosage form of antibiotics was prepared by the immobilization of complexes on activated carbon. Release of the major quantity of antibiotics was proved by HPLC method to be in alkaline media modeling the intestine.В настоящее время актуальна направленная модификация антибиотиков с целью создания кислоторезистентных лекарственных форм, пригодных для перорального применения. В настоящей работе были синтезированы полимерные комплексы цефалоспориновых антибиотиков третьего поколения цефтриаксона и цефотаксима с водорастворимым производным целлюлозы – сульфатом ацетатом в форме натриевой соли. Полученные комплексы охарактеризованы методами УФ- и ИК-спектроскопии. Путем иммобилизации комплекса на активированном угле получены кислотоустойчивые таблетированные лекарственные формы для перорального применения, которые могут быть предложены для проведения доклинических и клинических испытаний.