Parameter selection for the supply system in a Pilger mill

The braking chamber in the supply system of a Pilger pipe mill is modernized. The influence of constant and variable parameters of the supply system on braking is studied. © 2013 Allerton Press, Inc

BBGKY kinetic approach for an e-e+gamma plasma created from the vacuum in a strong laser-generated electric field: The one-photon annihilation channel

In the present work a closed system of kinetic equations is obtained from the truncation of the BBGKY hierarchy for the description of the vacuum creation of an electron - positron plasma and secondary photons due to a strong laser field. This truncation is performed in the Markovian approximation for the one-photon annihilation channel which is accessible due to the presence of the strong external field. Estimates of the photon production rate are obtained for different domains of laser field parameters (frequency nu and field strength E). A huge quantity of optical photons of the quasiclassical laser field is necessary to satisfy the conservation laws of energy and momentum of the constituents (e-, e+, gamma) in this channel. Since the number of these optical photons corresponds to the order of perturbation theory, a vanishingly small photon production rate results for the optical region and strongly subcritical fields E << E_c. In the gamma-ray region nu <~ m the required number of laser photons is small and the production rate of photons from the one-photon annihilation process becomes accessible to observations for subcritical fields E <~ E_c. In the infrared region the photon distribution has a 1/k spectrum typical for flicker noise.Comment: 14 pages, 1 figure, one reference with referring text added and one citation correcte

A Hydrophobic Gate in an Ion Channel: The Closed State of the Nicotinic Acetylcholine Receptor

The nicotinic acetylcholine receptor (nAChR) is the prototypic member of the `Cys-loop' superfamily of ligand-gated ion channels which mediate synaptic neurotransmission, and whose other members include receptors for glycine, gamma-aminobutyric acid, and serotonin. Cryo-electron microscopy has yielded a three dimensional structure of the nAChR in its closed state. However, the exact nature and location of the channel gate remains uncertain. Although the transmembrane pore is constricted close to its center, it is not completely occluded. Rather, the pore has a central hydrophobic zone of radius about 3 A. Model calculations suggest that such a constriction may form a hydrophobic gate, preventing movement of ions through a channel. We present a detailed and quantitative simulation study of the hydrophobic gating model of the nicotinic receptor, in order to fully evaluate this hypothesis. We demonstrate that the hydrophobic constriction of the nAChR pore indeed forms a closed gate. Potential of mean force (PMF) calculations reveal that the constriction presents a barrier of height ca. 10 kT to the permeation of sodium ions, placing an upper bound on the closed channel conductance of 0.3 pS. Thus, a 3 A radius hydrophobic pore can form a functional barrier to the permeation of a 1 A radius Na+ ion. Using a united atom force field for the protein instead of an all atom one retains the qualitative features but results in differing conductances, showing that the PMF is sensitive to the detailed molecular interactions.Comment: Accepted by Physical Biology; includes a supplement and a supplementary mpeg movie can be found at http://sbcb.bioch.ox.ac.uk/oliver/download/Movies/watergate.mp

Self - Consistent Description of e+e-gamma Plasma Created from the Vacuum in a Strong Electric Laser Field

In the present work a closed system of kinetic equations is obtained for the description of the vacuum creation of an electron - positron plasma and secondary photons due to a strong laser field. An estimate for the photon energy distribution is obtained. In the Markovian approximation the photon distribution has a 1/k spectrum (flicker noise).Comment: 6 pages, contribution to Proceedings of the International Bogolyubov Conference, Dubna (Russia), August 21-27, 200

Inertial mechanism: dynamical mass as a source of particle creation

A kinetic theory of vacuum particle creation under the action of an inertial mechanism is constructed within a nonpertrubative dynamical approach. At the semi-phenomenological level, the inertial mechanism corresponds to quantum field theory with a time-dependent mass. At the microscopic level, such a dependence may be caused by different reasons: The non-stationary Higgs mechanism, the influence of a mean field or condensate, the presence of the conformal multiplier in the scalar-tensor gravitation theory etc. In what follows, a kinetic theory in the collisionless approximation is developed for scalar, spinor and massive vector fields in the framework of the oscillator representation, which is an effective tool for transition to the quasiparticle description and for derivation of non-Markovian kinetic equations. Properties of these equations and relevant observables (particle number and energy densities, pressure) are studied. The developed theory is applied here to describe the vacuum matter creation in conformal cosmological models and discuss the problem of the observed number density of photons in the cosmic microwave background radiation. As other example, the self-consistent evolution of scalar fields with non-monotonic self-interaction potentials (the W-potential and Witten - Di Vecchia - Veneziano model) is considered. In particular, conditions for appearance of tachyonic modes and a problem of the relevant definition of a vacuum state are considered.Comment: 51 pages, 18 figures, submitted to PEPAN (JINR, Dubna); v2: added reference

Game-Theoretic Model for the Interaction of the Online Course Design Process Participants within the University

Активное развитие рынка цифровых образовательных ресурсов и, в частности, онлайн-курсов (ОК), используемых в системе высшего образования, определяет актуальность проблемы повышения конкурентоспособности ОК как рыночных продуктов. Значимую роль в создании качественных конкурентоспособных ОК играет организационно-правовая система взаимодействия между авторами и университетом. Данная статья посвящена разработке теоретико-игровой модели взаимодействия между участниками процесса создания ОК, позволяющей выявить оптимальные (взаимовыгодные) варианты и условия партнерского взаимодействия авторов ОК и университета. Для представления этого взаимодействия в терминах теории игр проанализированы особенности создания ОК и рассмотрены подходы к применению теории игр в инновационной сфере. Впервые предложена математическая игровая модель типовой ситуации создания и коммерциализации ОК с участием университета и автора – университетского работника. Представленная типовая ситуация создания и коммерциализации ОК классифицирована как динамическая, конечная, парная, неантагонистическая, некооперативная игра с полной совершенной информацией. Методом обратной индукции было найдено равновесие Нэша, совершенное на подыграх, и определен профиль оптимальных стратегий. Анализ решения выявил условия, при которых оптимальным оказывается партнерское взаимодействие авторов онлайн-курсов и университета. Полученные результаты могут быть использованы университетом в качестве инструмента для обоснования и формирования стратегии взаимовыгодного сотрудничества с авторами ОК, позволят находить или усовершенствовать формы этого взаимодействия.The market of digital educational resources and, in particular, online courses for the higher education system is actively developing. A significant role in creating a high-quality competitive online course is played by the organizational and legal system of interaction between authors and the university. This research article aims at developing a game-theoretical model of interaction between the participants of online course creating process in order to identify optimal (mutually beneficial) options and conditions for partnership interaction between the authors of online courses and the university. To represent the interaction between the authors and the university in terms of game theory, there are analyzed the specific features of creating an online course. The authors are the first to construct a mathematical game model for a typical situation of commercializing an online course within the university-and-author interaction. This situation is interpreted as a dynamic finite paired non-antagonistic non-cooperative game with complete perfect information. The Nash equilibrium, perfect on subgames, is found by the method of backward induction; the profile of optimal strategies is determined. The analysis of the results can help to substantiate, form and improve the strategy of mutually beneficial cooperation between the authors of the online course and the university

AUTOIMMUNE ORIGIN OF SARCOIDOSIS: DETERMINATION OF SPECIFIC IMMUNE COMPLEXES IN PATIENTS WITH RESPIRATORY SARCOIDOSIS

The etiology of sarcoidosis is not completely understood. A hypothesis exists about the relationship between sarcoidosis and a complex of pathological autoimmune reactions that occur under the influence of triggering factors. In this study, specific immune complexes in the blood plasma of patients have been determined, which can indirectly reveal the causes of the disease.The study included 33 patients with lung sarcoidosis (I group), compared to 24 healthy donors who served as a control group (II group). The patients underwent standard examination. Their blood plasma was investigated by the dynamic light scattering method with addition of tuberculosis antigens (ESAT-6/SFP-10) and “lung healthy tissue extract”. Statistical analysis was performed using the Statistica 7.0 program. Test results were considered significant at p &lt; 0.05.Аccording to the data obtained, addition of ESAT-6/SFP-10 to patient’s blood plasma almost did not lead to the formation of immune complexes in most samples. Meanwhile, development of such complexes after addition of “lung tissue extract” was revealed in all the patients. The immune complexes were not detected in any donor from control group after stimulation with both kinds of antigens (p &lt; 0.01).The data on distinct formation of immune complexes with the addition of “lung healthy tissue extract” in patients with lung sarcoidosis may be considered an indirect evidence for occurrence of autoimmune reaction under the influence of some pathogenic factors. Absence of de novo immune complex formation after addition of tuberculosis antigens (ESAT-6/SFP-10) makes it unlikely any direct effects of tuberculosis bacteria upon development of sarcoidosis