Subbarrier absorption in a stationary superlattice

The calculation of the interband absorption coefficient was carried out in the classical case, when the frequency of light was assumed to bind two miniband subbarrier states of different bands. The influence of two dimensional Mott excitons on this absorption was studied and a comparison was made with the experiment. All of these considerations were done taking into account the photon wave vector (the phase spatial heterogeneity). The basic traits of the energy spectra of superlattice semiconductors, their kinetic and optical properties, and possible means of electromagnetic wave intensification were examined. By the density matrix method, a theory of electrical and electromagnetic properties of superlattices was suggested

Interdisciplinary Approach to the Mental Lexicon: Neural Network and Text Extraction From Long-term Memory

The paper touches upon the principles of mental lexicon organization in the light of recent research in psycho- and neurolinguistics. As a focal point of discussion two main approaches to mental lexicon functioning are considered: modular or dual-system approach, developed within generativism and opposite single-system approach, representatives of which are the connectionists and supporters of network models. The paper is an endeavor towards advocating the viewpoint that mental lexicon is complex psychological organization based upon specific composition of neural network. In this regard, the paper further elaborates on the matter of storing text in human mental space and introduces a model of text extraction from long-term memory. Based upon data available, the author develops a methodology of modeling structures of knowledge representation in the systems of artificial intelligence

Self-Adjointness of Generalized MIC-Kepler System

We have studied the self-adjointness of generalized MIC-Kepler Hamiltonian, obtained from the formally self-adjoint generalized MIC-Kepler Hamiltonian. We have shown that for \tilde l=0, the system admits a 1-parameter family of self-adjoint extensions and for \tilde l \neq 0 but \tilde l <{1/2}, it has also a 1-parameter family of self-adjoint extensions.Comment: 11 pages, Latex, no figur

Origin of second-harmonic generation in the incommensurate phase of K2SeO4

We show that a ferroelectric phase transition takes place in the incommensurate phase of the K2SeO4 crystal. The ferroelectric character of the IC phase explains the second-harmonic generation observed in the corresponding temperature range.Comment: 5 pages, 1 figur

Effect of CPAP therapy on left atrial remodeling in patients with paroxysmal atrial fibrillation and obstructive sleep apnea undergoing pulmonary vein isolation

Aim. To study the isolated effect of obstructive sleep apnea (OSA) on left atrial (LA) remodeling in patients with paroxysmal atrial fibrillation (AF) who underwent pulmonary vein (PV) ablation and concomitant severe and moderate OSA.Material and methods. A subanalysis of echocardiographic data was performed in 50 patients with paroxysmal AF and moderate/severe OSA who underwent PV isolation and were followed up for 12 months (main group, 33; control group, 17). The clinical efficacy of catheter ablation was assessed after the end of the threemonth blind period. The following echocardiographic parameters were included in the subanalysis: anterior-posterior LA dimension, LA volume, LA volume index (LAVI), and pulmonary artery systolic pressure (PASP).Results. After 12 months, the control group showed a significant increase in the anterior-posterior LA dimension (40,5 (40-42) mm vs 42 (40-45) mm, p=0,037), LA volume (68,5 (58-74,5) ml vs 69 (63-89) ml, p=0,006), LAVI (35,0 (29-37) ml/m2 vs 35,5 (32-41,5) ml/m2, p=0,005) and PASP (27 (25-30) vs 30 (29-33), p=0,004). Intragroup analysis of patients not receiving continuous positive airway pressure (CPAP) therapy and without recurrent AF did not reveal significant changes in LA size (anterior-posterior LA dimension — 40 (40-42) mm vs 40 (40- 41) mm, p=0,317; LA volume — 63 (58-71) ml vs 64 (61-69) ml, p=0,509; LAVI — 32 (29-36) ml/m2 vs 33 (31-34) ml2, p=0,509).Conclusion. In patients with paroxysmal AF and concomitant moderate to severe OSA who underwent AF catheter treatment, the absence of CPAP therapy is not associated with a significant increase in the linear and volume LA dimensions in the absence of AF recurrence

Заболеваемость раком кожи в Красноярском крае

Scin neoplasms are among the most common oncological diseases with the prevalence of basalioma. The paper рresents statistical analysis of the data of skin cancer morbidity and mortality rates in Krasnoyarsk Region summarized for the period since 1999 until 2007. In structure of the skin cancer morbidity defines a share basalioma and squamous cell carcinoma.Новообразования кожи занимают одно из первых мест в структуре онкологических заболеваний. Подавляющую часть среди онкологической патологии составляет базально-клеточный рак кожи. Проведен статистический анализ заболеваемости раком кожи в Красноярском крае, исследована ее динамика и структура за период с 1999 по 2007 г. В структуре заболеваемости раком кожи определена доля базалиомы и плоскоклеточного рака

Частотные характеристики полосковых модулей формирования квазихаотических сигналов на основе объемных нелинейно- оптических кристаллов

In this paper the experimental study of frequency dependences of scattering matrix coefficients of strip modules based on a coplanar strip line with partial dielectric filling in the form of bulk non-linear optical crystals of quartz, potassium titanium phosphate (KTP), zinc germanium diphosphide, lithium niobate has been performed. The appearance of the effect of forming quasi- chaotic oscillations in modules containing KTiOPO4, ZnGeP2, LiNbO3 bulk crystals when LFM signals are fed at fast switching of incident wave direction in the receiving and transmitting tract of the vector network analyzer is demonstrared. Parameters of comparative characterization of crystal materials are introduced. The complete phase of the modulus transmission coefficient is determined.  The analysis of its physical sense is made, followed by processing complete phase shift, which provides the possibility to develop the algorithm of estimating the frequency dependence of crystal’s relative permittivity. The studied modules may be used as formers of quasi- chaotic microwave signals. Arutyunyan A. A., Malyutin N. D., Malyutin G. A., Podzyvalov S. N., Yudin N. N. Frequency characteristics of strip modules of the quasi- chaotic signals formation based on bulk nonlinear optical crystals. Ural Radio Engineering Journal. 2023;7(3):227–249. (In Russ.) DOI: 10.15826/urej.2023.7.3.001В работе проведено экспериментальное исследование частотных зависимостей коэффициентов матрицы рассеяния полосковых модулей на основе копланарной полосковой линии с частичным диэлектрическим заполнением в виде объемных нелинейно-оптических кристаллов кварца SiO2, титанил-фосфата калия KTiOPO4 (KTP), дифосфида цинка германия ZnGeP2, ниобата лития LiNbO3. Показано возникновение эффекта формирования квазихаотических колебаний в модулях, содержащих объемные кристаллы KTiOPO4, ZnGeP2, LiNbO3 при подаче на вход ЛЧМ-сигналов с быстрым переключением направления падающей волны в тракте приема-передачи векторного анализатора цепей. Введены параметры для сравнительной характеристики материалов кристаллов. Определена полная (развернутая) фаза коэффициента передачи модулей. Проведены анализ ее физического смысла и обработка полной фазы, позволившая построить алгоритм оценки частотной зависимости относительной диэлектрической проницаемости кристаллов. Исследованные модули могут выполнять функцию формирователей квазихаотических сигналов СВЧ. Арутюнян А. А., Малютин Н. Д., Малютин Г. А., Подзывалов С. Н., Юдин Н. Н. Частотные характеристики полосковых модулей формирования квазихаотических сигналов на основе объемных нелинейно- оптических кристаллов. Ural Radio Engineering Journal. 2023;7(3):227– 249. DOI: 10.15826/urej.2023.7.3.001

On a Generalized Kepler-Coulomb System: Interbasis Expansions

This paper deals with a dynamical system that generalizes the Kepler-Coulomb system and the Hartmann system. It is shown that the Schr\"odinger equation for this generalized Kepler-Coulomb system can be separated in prolate spheroidal coordinates. The coefficients of the interbasis expansions between three bases (spherical, parabolic and spheroidal) are studied in detail. It is found that the coefficients for the expansion of the parabolic basis in terms of the spherical basis, and vice-versa, can be expressed through the Clebsch-Gordan coefficients for the group SU(2) analytically continued to real values of their arguments. The coefficients for the expansions of the spheroidal basis in terms of the spherical and parabolic bases are proved to satisfy three-term recursion relations.Comment: 24 pages, Latex, LYCEN 941

Measurement of Dielectric Suppression of Bremsstrahlung

In 1953, Ter-Mikaelian predicted that the bremsstrahlung of low energy photons in a medium is suppressed because of interactions between the produced photon and the electrons in the medium. This suppression occurs because the emission takes place over on a long distance scale, allowing for destructive interference between different instantaneous photon emission amplitudes. We present here measurements of bremsstrahlung cross sections of 200 keV to 20 MeV photons produced by 8 and 25 GeV electrons in carbon and gold targets. Our data shows that dielectric suppression occurs at the predicted level, reducing the cross section up to 75 percent in our data.Comment: 11 pages, format is postscript file, gzip-ed, uuencode-e

Coordination as a function of skill level in the gymnastics longswing

The purpose of this study was to investigate the nature of inter-joint coordination at different levels of skilled performance to: (1) distinguish learners who were successful versus unsuccessful in terms of their task performance; (2) investigate the pathways of change during the learning of a new coordination pattern and (3) examine how the learner’s coordination patterns relate to those of experts in the longswing gymnastics skill. Continuous relative phase of hip and shoulder joint motions was examined for longswings performed by two groups of novices, successful (n = 4) and unsuccessful (n = 4) over five practice sessions, and two expert gymnasts. Principal component analysis showed that during longswing positions where least continuous relative phase variability occurred for expert gymnasts, high variability distinguished the successful from the unsuccessful novice group. Continuous relative phase profiles of successful novices became more out-of-phase over practice and less similar to the closely in-phase coupling of the expert gymnasts. Collectively, the findings support the proposition that at the level in inter-joint coordination a technique emerges that facilitates successful performance but is not more like an expert’s movement coordination. This finding questions the appropriateness of inferring development towards a “gold champion” movement coordination