Латинська Америка в дослідженнях російських етнографів за останні тридцять років

Статья посвящена истории исследований в области латиноамериканистики российскими и советскими учёными на примере научной деятельности сотрудников Института этнографии им. Н. Н. Миклухо-Маклая АН СССР (московское и ленинградское отделения).The article is dedicated to the Latin American researches provided by the Russian and Soviet scientists illustrated with the scientific activities of the representatives of the Soviet Academy of Science’s Myklukho-Maklai Ethnographical Institute (Moscow and Leningrad branches)

A Double-Mode RR Lyrae Star with a Strong Fundamental Mode Component

NSVS 5222076, a thirteenth magnitude star in the Northern Sky Variability Survey, was identified by Oaster as a possible new double-mode RR Lyrae star. We confirm the double-mode nature of NSVS 5222076, supplementing the survey data with new V band photometry. NSVS 5222076 has a fundamental mode period of 0.4940 day and a first overtone period of 0.3668 day. Its fundamental mode light curve has an amplitude twice as large as that of the first overtone mode, a ratio very rarely seen. Data from the literature are used to discuss the location in the Petersen diagram of double-mode RR Lyrae stars having strong fundamental mode pulsation. Such stars tend to occur toward the short period end of the Petersen diagram, and NSVS 5222976 is no exception to this rule.Comment: 14 pages, 4 figures, To be published in the March, 2006, issue of PAS

Термопружний стан шаруватих термочутливих циліндрів і куль за конвективно-променевого теплообміну

Розроблено методику розв’язування одновимірних статичних задач термопружності для шаруватих циліндрів і куль за конвективно-променевого нагрівання з урахуванням лінійної залежності коефіцієнтів теплопровідності та довільного характеру залежності інших фізико-механічних характеристик від температури. Задачі теплопровідності зведено, незалежно від кількості шарів, до розв’язування системи двох нелінійних алгебричних рівнянь. У задачах термопружності неперервні в межах кожного шару коефіцієнти рівнянь апроксимовано кусково-сталими функціями. Проведено числовий аналіз температурних полів і напружень у двошарових тілах.The method for solving one-dimensional static thermoelasticity problems is developed for layered cylinders and spheres under convective and radiation heating, taking into account linear dependence of heat conductivity coefficients and arbitrary character of dependence of other physical and mechanical characteristics on a temperature. Problems of heat conductivity have been reduced to the system of two nonlinear algebraic equations regardless of the number of layers. In the thermoelasticity problems the continuous within every layer coefficients of equations are approximated by piecewise constant functions. The numerical analysis of the temperature fields and stresses is conducted for two-layered bodies.Разработана методика решения одномерных статических задач термоупругости для слоистых цилиндров и сфер при конвективно-лучевом нагреве с учетом линейной зависимости коэффициентов теплопроводности и произвольного характера зависимости других физико-механических характеристик от температуры. Задачи теплопроводности сведены, независимо от количества слоев, к решению системы двух нелинейных алгебраических уравнений. В задачах термоупругости непрерывные в пределах каждого слоя коэффициенты уравнений аппроксимированы кусочно-постоянными функциями. Проведен численный анализ температурных полей и напряжений в двухслойных телах

Phase-fluctuating 3D condensates in elongated traps

We find that in very elongated 3D trapped Bose gases, even at temperatures far below the BEC transition temperature Tc, the equilibrium state will be a 3D condensate with fluctuating phase (quasicondensate). At sufficiently low temperatures the phase fluctuations are suppressed and the quasicondensate turns into a true condensate. The presence of the phase fluctuations allows for extending thermometry of Bose-condensed gases well below those established in current experiments.Comment: 5 pages REVTeX, 3 figures, misprints correcte

Распределение металлической фазы в синтетических алмазах типа «карбонадо»

Studying of a structural structure synthetic «carbonado» is spent by a method of electronic scanning microscopy. It is established, that the surface «carbonado» is covered by the large diamond crystals reaching 200 microns, having obviously expressed structure of growth. On a surface of these crystals observed drops of metal-catalyst (nickel) of a submicronic range. It is established, that the structure synthetic «carbonado» represents interpenetrating skeletons from diamond and ceramic-metal phases

Regimes of quantum degeneracy in trapped 1D gases

We discuss the regimes of quantum degeneracy in a trapped 1D gas and obtain the diagram of states. Three regimes have been identified: the BEC regimes of a true condensate and quasicondensate, and the regime of a trapped gas of Tonks (gas of impenetrable bosons). The presence of a sharp cross-over to the BEC regime requires extremely small interaction between particles. We discuss how to distinguish between true and quasicondensates in phase coherence experiments.Comment: 4 pages, 1 eps figur

Cognitive Spectrum Management in Dynamic Cellular Environments: : A Case-Based Q-Learning Approach

This paper examines how novel cellular system architectures and intelligent spectrum management techniques can be used to play a key role in accommodating the exponentially increasing demand for mobile data capacity in the near future. A significant challenge faced by the artificial intelligence methods applied to such flexible wireless communication systems is their dynamic nature, e.g. network topologies that change over time. This paper proposes an intelligent case-based Q-learning method for dynamic spectrum access (DSA) which improves and stabilises the performance of cognitive cellular systems with dynamic topologies. The proposed approach is the combination of classical distributed Q-learning and a novel implementation of case-based reasoning which aims to facilitate a number of learning processes running in parallel. Large scale simulations of a stadium small cell network show that the proposed case-based Q-learning approach achieves a consistent improvement in the system quality of service (QoS) under dynamic and asymmetric network topology and traffic load conditions. Simulations of a secondary spectrum sharing scenario show that the cognitive cellular system that employs the proposed case-based Q-learning DSA scheme is able to accommodate a 28-fold increase in the total primary and secondary system throughput, but with no need for additional spectrum and with no degradation in the primary user QoS

Damping of low-energy excitations of a trapped Bose condensate at finite temperatures

We present the theory of damping of low-energy excitations of a trapped Bose condensate at finite temperatures, where the damping is provided by the interaction of these excitations with the thermal excitations. We emphasize the key role of stochastization in the behavior of the thermal excitations for damping in non-spherical traps. The damping rates of the lowest excitations, following from our theory, are in fair agreement with the data of recent JILA and MIT experiments. The damping of quasiclassical excitations is determined by the condensate boundary region, and the result for the damping rate is drastically different from that in a spatially homogeneous gas.Comment: 10 pages RevTeX, correction of the misprints and addition of the sentence clarifying the result for quasiclassical excitationscorrection of the misprints and addition of the sentence clarifying the result for quasiclassical excitation

Bose-Einstein condensation in quasi2D trapped gases

We discuss BEC in (quasi)2D trapped gases and find that well below the transition temperature $T_c$ the equilibrium state is a true condensate, whereas at intermediate temperatures $T<T_c$ one has a quasicondensate (condensate with fluctuating phase). The mean-field interaction in a quasi2D gas is sensitive to the frequency $\omega_0$ of the (tight) confinement in the "frozen" direction, and one can switch the sign of the interaction by changing $\omega_0$. Variation of $\omega_0$ can also reduce the rates of inelastic processes, which opens prospects for tunable BEC in trapped quasi2D gases.Comment: 4 revtex pages, 1 figure, text is revised, figure improve

Calibrating the Cepheid Period-Luminosity relation from the infrared surface brightness technique I. The p-factor, the Milky Way relations, and a universal K-band relation

We determine Period-Luminosity relations for Milky Way Cepheids in the optical and near-IR bands. These relations can be used directly as reference for extra-galactic distance determination to Cepheid populations with solar metallicity, and they form the basis for a direct comparison with relations obtained in exactly the same manner for stars in the Magellanic Clouds, presented in an accompanying paper. In that paper we show that the metallicity effect is very small and consistent with a null effect, particularly in the near-IR bands, and we combine here all 111 Cepheids from the Milky Way, the LMC and SMC to form a best relation. We employ the near-IR surface brightness (IRSB) method to determine direct distances to the individual Cepheids after we have recalibrated the projection factor using the recent parallax measurements to ten Galactic Cepheids and the constraint that Cepheid distances to the LMC should be independent of pulsation period. We confirm our earlier finding that the projection factor for converting radial velocity to pulsational velocity depends quite steeply on pulsation period, p=1.550-0.186*log(P) in disagrement with recent theoretical predictions. We delineate the Cepheid PL relation using 111 Cepheids with direct distances from the IRSB analysis. The relations are by construction in agreement with the recent HST parallax distances to Cepheids and slopes are in excellent agreement with the slopes of apparent magnitudes versus period observed in the LMC.Comment: Accepted for publication by Astronomy and Astrophysics. 15 pages, 11 figure