Quantum Transparency of Barriers for Structure Particles

Penetration of two coupled particles through a repulsive barrier is considered. A simple mechanism of the appearance of barrier resonances is demonstrated that makes the barrier anomalously transparent as compared to the probability of penetration of structureless objects. It is indicated that the probabilities of tunnelling of two interacting particles from a false vacuum can be considerably larger than it was assumed earlier.Comment: Revtex, 4 pages, 4 figure

Mathematical modelling of liquid meniscus shape in cylindrical micro-channel for normal and micro gravity conditions

Mathematical model of liquid meniscus shape in cylindrical micro-channel of the separator unit of condensing/separating system is presented. Moving liquid meniscus in the 10 μm cylindrical microchannel is used as a liquid lock to recover the liquid obtained by condensation from the separators. The main goal of the liquid locks to prevent penetration of a gas phase in the liquid line at the small flow rate of the condensate and because of pressure fluctuations in the vapor-gas-liquid loop. Calculation of the meniscus shape has been performed for liquid FC-72 at different values of pressure difference gas - liquid and under normal and micro gravity conditions

Resonant enhanced diffusion in time dependent flow

Explicit examples of scalar enhanced diffusion due to resonances between different transport mechanisms are presented. Their signature is provided by the sharp and narrow peaks observed in the effective diffusivity coefficients and, in the absence of molecular diffusion, by anomalous transport. For the time-dependent flow considered here, resonances arise between their oscillations in time and either molecular diffusion or a mean flow. The effective diffusivities are calculated using multiscale techniques.Comment: 18 latex pages, 11 figure

A conserved alternative splice in the von Recklinghausen neurofibromatosis (NF1) gene produces two neurofibromin isoforms, both of which have GTPase-activating protein activity

Sequence analysis has shown significant homology between the catalytic regions of the mammalian ras GTPase-activating protein (GAP), yeast Ira1p and Ira2p (inhibitory regulators of the RAS-cyclic AMP pathway), and neurofibromin, the protein encoded by the NF1 gene. Yeast expression experiments have confirmed that a 381-amino-acid segment of neurofibromin, dubbed the GAP-related domain (GRD), can function as a GAP. Using the RNA polymerase chain reaction with primers flanking the NF1-GRD, we have identified evidence for alternative splicing in this region of the NF1 gene. In addition to the already published sequence (type I), an alternative RNA carrying a 63-nucleotide insertion (type II) is present in all tissues examined, although the relative amounts of types I and II vary. The insertion is conserved across species but is not present in GAP, IRA1, or IRA2. GenBank searches have failed to identify significant similarity between the inserted sequence and known DNA or protein sequences, although the basic amino acid composition of the insertion shares features with nuclear targeting sequences. Expression studies in yeasts show that despite the partial disruption of the neurofibromin-IRA-GAP homology by this insertion, both forms of the NF1-GRD can complement loss of IRA function. In vivo assays designed to compare the GAP activity of the two alternatively spliced forms of the NF1-GRD show that both can increase the conversion of GTP-bound ras to its GDP-bound form, although the insertion of the 21 amino acids weakens this effect. The strong conservation of this alternative, splicing suggests that both type I and II isoforms mediate important biological functions of neurofibromin

On the characterisation of a Bragg spectrometer with X-rays from an ECR source

Narrow X-ray lines from helium-like argon emitted from a dedicated ECR source have been used to determine the response function of a Bragg crystal spectrometer equipped with large area spherically bent silicon (111) or quartz (10$\bar{1}$) crystals. The measured spectra are compared with simulated ones created by a ray-tracing code based on the expected theoretical crystal's rocking curve and the geometry of the experimental set-up.Comment: Version acceptee (NIM

Examination of the astrophysical S-factors of the radiative proton capture on 2H, 6Li, 7Li, 12C and 13C

Astrophysical S-factors of radiative capture reactions on light nuclei have been calculated in a two-cluster potential model, taking into account the separation of orbital states by the use of Young schemes. The local two-body potentials describing the interaction of the clusters were determined by fitting scattering data and properties of bound states. The many-body character of the problem is approximatively accounted for by Pauli forbidden states. An important feature of the approach is the consideration of the dependence of the interaction potential between the clusters on the orbital Young schemes, which determine the permutation symmetry of the nucleon system. Proton capture on 2H, 6Li, 7Li, 12C, and 13C was analyzed in this approach. Experimental data at low energies were described reasonably well when the phase shifts for cluster-cluster scattering, extracted from precise data, were used. This shows that decreasing the experimental error on differential elastic scattering cross sections of light nuclei at astrophysical energies is very important also to allow a more accurate phase shift analysis. A future increase in precision will allow more definite conclusions regarding the reaction mechanisms and astrophysical conditions of thermonuclear reactions.Comment: 40p., 9 fig., 83 ref. arXiv admin note: substantial text overlap with arXiv:1005.1794, arXiv:1112.1760, arXiv:1005.198

СТРУКТУРНО-ВЕЩЕСТВЕННАЯ МОДЕЛЬ СТАНОВЛЕНИЯ КИМБЕРЛИТОВОЙ ТРУБКИ НЮРБИНСКАЯ (СРЕДНЕ-МАРХИНСКИЙ РАЙОН ЯКУТСКОЙ АЛМАЗОНОСНОЙ ПРОВИНЦИИ)

The paper presents the results of comprehensive study of the primary diamond deposit of the Nyurbinskaya pipe in the Yakutian diamondiferous province. It is established, that the pipe is confined to the fault junction of four directions and is composed of the kimberlite of four phases. Analysis of different faults and tectonic fracturing allowed to reconstruct the tectonic stress fields acting at the stage of the kimberlite body formation and to determine their occurrence sequence in time. The data obtained about regularities of the Nyurbinskaya pipe compositional structure and results of geologo-structural studies are combined in a single structural-compositional model of the deposit formation. Peculiarities of the fault network operation during the deposit formation stage are confirmed by experimental results using polarization-optical method. The model allowed to formulate the basic structural characteristics of the prospecting works object within which the formation of kimberlite body type of the Nyurbinskaya pipe is possible and to determine the elements of the fault network which are promising for the kimberlite pipes discovery.В статье представлены результаты комплексного изучения коренного месторождения алмазов трубка Нюрбинская. Установлено, что трубка приурочена к узлу разломов четырех направлений и сложена кимберлитами четырех фаз. Анализ разноранговых разрывных нарушений и тектонической трещиноватости позволил восстановить поля тектонических напряжений, действовавшие на этапе формирования кимберлитового тела и определить последовательность их проявления во времени. Полученные данные о закономерностях вещественного строения трубки Нюрбинской и результаты геолого-структурных исследований объединены в рамках единой структурно-вещественной модели формирования месторождения. Особенности функционирования разрывной сети на этапе формирования месторождения подтверждены результатами экспериментов с использованием поляризационно-оптического метода. Полученная модель позволила сформулировать признаки, определяющие основные структурные характеристики объекта поисковых работ, в пределах которого возможно формирование кимберлитовых тел типа трубки Нюрбинской, и на их основании выделить те элементы разломной сети (разломные узлы), которые являются перспективными для обнаружения кимберлитовых трубок

Physical culture as a mean for prophylaxis and traetment deseases

This article examines features of physical culture’s impacts on the human organism and represented information about reasons of passive relationship between physical culture and human organismВ данной статье рассмотрены особенности влияния физических нагрузок на организм человека и представлены данные о причинах пассивного отношения к занятиям физической культурой и положительном влиянии физической культуры на здоровье человек