Analysis of optical magnetoelectric effect in GaFeO_3

We study the optical absorption spectra in a polar ferrimagnet GaFeO_3. We consider the E1, E2 and M1 processes on Fe atoms. It is shown that the magnetoelectric effect on the absorption spectra arises from the E1-M1 interference process through the hybridization between the 4p and 3d states in the noncentrosymmetry environment of Fe atoms. We perform a microscopic calculation of the spectra on a cluster model of FeO_6 consisting of an octahedron of O atoms and an Fe atom displaced from the center with reasonable values for Coulomb interaction and hybridization. We obtain the magnetoelectric spectra, which depend on the direction of magnetization, as a function of photon energy in the optical region 1.0-2.5 eV, in agreement with the experiment.Comment: 18 pages, 5 figure

Effect of Stress on Irradiation-induced Creep and Swelling of Fe-18Cr-10Ni-Ti Steel Pressurized Specimens Irradiated in the BOR-60 Reactor

The paper presents the data on the effect of stress of various signs on the irradiationinduced creep strain and swelling of austenitic Fe-18Cr-10Ni-Ti steel pressurized specimens. The pressurized specimens of standard and contoured geometry were irradiated in the BOR-60 reactor up to the damage dose of 90 and 36 dpa, accordingly,under various stress levels applied. Presented are the data resulted from TEM investigations of pressurized specimens performed with the use of the transmission electron microscope

New way of laparoscopic intracorporeal term-terminal invagination ileotransverse anastomosis

Background. Laparoscopic surgery becomes a standard treatment for many surgical diseases. Defects of a stapler laparoscopic mechanical suture during the formation of an anastomosis after hemicolectomy are detected in 18% of observed cases.Objective. Development, substantiate reproducibility and safety of a manual intracorporeal term-terminal invagination ileotransverse anastomosis method after performing the right laparoscopic hemicolectomy.Material and Methods. Authors presented a description of the technique and their own experience of performing laparoscopic hemicolectomy on the right with the formation of a manual original anastomosis in 10 patients with pathology of the right half of the colon. Eight patients (80.0%) had a malignant tumor of the right half of the colon, 1 patient (10.0%) showed multiple polyps of the cecum and the ascending part of the colon, 1 patient (10.0%) developed a cystic-solid submucosa tumor of the ileocecal angle. One patient had metastatic lung disease at the time of establishing diagnosis. The postoperative follow-up period was 7–18 months.Results. There were no conversions to open surgery. All operations (n = 10) were ended completely laparoscopically – right hemicolectomy with standard D2 lymph node dissection. In one patient, we revealed intraoperatively the spread of the tumor to the gallbladder, which required additional cholecystectomy. The duration of the operation was 122.5 ± 10.7 min.; median blood loss was 107 ± 5.2 ml. At the time of follow-up all patients are alive.Conclusion. The technique is universal in the surgical treatment of patients with various pathologies of the right half of the colon

Common Carotid Artery Occlusion and Double-Nucleated Cellular Structures In The Rat Sensorimotor Cerebral Cortex

The aim of the study. To study the double-nucleated cellular structures of the brain sensorimotor cortex (SMC) of sexually mature white rats after a 40-minute occlusion of the common carotid arteries.Methods. Acute ischemia was simulated in white Wistar rats by 40-minute occlusion of the common carotid arteries (OCCA). We performed comparative morphometric evaluation of cyto-, dendro-, synapto-, and glioar-chitectonics of the neocortex in intact animals (n=5), and 1 (n=5), 3 (n=5), and 7 days (n=5) after OCCA. We used Nissl, hematoxylin and eosin staining, and immunohistochemical reactions for NSE, MAP-2, HSP-70, p38, caspase-3, GFAP, AIF1, and Ki-67. Numerical density of pyramidal neurons, oligodendrocytes (ODCs), mi-croglyocytes (MGCs), presence of dystrophic and necrobiotic neurons with one or more nucleoli, hetero- and dikaryons were assessed. Statistical hypotheses were tested using Statistica 8.0 software.Results. The percentage of dystrophic and necrobiotic neurons, nerve cells with two nuclei or two or more nucleoli, the total number (proliferation) and percentage of hypertrophic astrocytes, ODCs and MGCs increased significantly after OCCA. The total numerical density of SMC neurons decreased by 26.4% (P=0.001) in layer III and by 18.5% in layer V (Mann-Whitney U Test; P=0.01) after OCCA throughout the observation period. Pathological and compensatory changes were diffusely focal and more pronounced in layer III of the neocortex. The density of bi-nucleated heterokaryons and dikaryons remained unchanged on days 1 and 3 after OCCA vs control and was 3.5 (1.5-4.0)/mm2, and increased to 6.5 (5.0-8.5)/mm2 on day 7 (Mann-Whitney U Test; P=0.002). This increase occurred along with a higher density of ODCs and MGCs than in the control. The maximum number of neurons with two or more nucleoli was also noted in layer III and V during this period.Conclusion. After 40-minute OCCA in SMC, parallel to the dystrophic and necrobiotic changes of pyramidal neurons and activation of neuroglial cells, there was an increase in the formation of heterokaryons and neurons with amplified nucleolus. These changes were considered as a variant of neuronal response to ischemic damage

Electromagnetically induced magnetochiral anisotropy in a resonant medium

Chirality has been extensively studied for well over a century, and its potential applications range from optics to chemistry, medicine, and biology. Ingenious experiments have been designed to measure this naturally small effect. Here we discuss the possibility of producing a medium having a large chiral effect by using the ideas of coherent control. The coherent fields resonant with appropriate transitions in atomic or molecular systems can be used to manipulate the optical properties of a medium. We demonstrate experimentally very large magnetochiral anisotropy by using electromagnetic fields in atomic Rb vapors.Peer reviewedPhysic

Исследование методов оценивания стабильности взаимного поведения стохастических процессов

The sensitivity of some methods for estimating the mutual dynamic stability of stochastic processes with given correlative properties was studied in relation to the phase detuning between the processes. Two classes of normally distributed random stochastic processes are considered: the processes with short-term correlation and the processes with a long-term correlation, characterized by the specified Hurst coefficients.На примере тестовых процессов с заданными корреляционными свойствами исследована чувствительность методов оценивания стабильности взаимной динамики стохастических процессов к фазовой расстройке между ними. Рассмотрены два класса нормально распределенных стохастических случайных процессов: процессы с кратковременной зависимостью и процессы с долговременной зависимостью, характеризующиеся заданным показателем Херста

Исследование методов оценивания стабильности взаимного поведения стохастических процессов

The sensitivity of some methods for estimating the mutual dynamic stability of stochastic processes with given correlative properties was studied in relation to the phase detuning between the processes. Two classes of normally distributed random stochastic processes are considered: the processes with short-term correlation and the processes with a long-term correlation, characterized by the specified Hurst coefficients.На примере тестовых процессов с заданными корреляционными свойствами исследована чувствительность методов оценивания стабильности взаимной динамики стохастических процессов к фазовой расстройке между ними. Рассмотрены два класса нормально распределенных стохастических случайных процессов: процессы с кратковременной зависимостью и процессы с долговременной зависимостью, характеризующиеся заданным показателем Херста

Исследование взаимной динамики стохастических нормально распределенных процессов при аддитивной амплитудной расстройке между ними

The joint analysis of several signals is essential for better understanding of the principles underlying the complex systems dynamics. We consider three methods for estimating the stability of the relative dynamics of two surrogate processes. The first one is based on calculation of the phase synchronization coefficient S and the second one on estimation of the cross-conditional entropy CE. The third approach uses the average value of the coherence function of the two processes - the coherence coefficient C. We study the sensitivity of these methods in relation to the amplitude randomization between test processes. All methods are applied to analyze two types of normally distributed random stochastic processes, with either short-term correlations characterized by finite correlation time or long-term correlations with theoretically infinite correlation time characterized by Hurst exponents. In our research, we generate two copies of the surrogate process with either short-term or long-term correlations. Then we attribute the additive white noise to one of these copies at first with the uniform distribution and then with the Gaussian distribution and the same variance. Next, we calculate the coefficients that characterize the mutual behavior of the two test processes and estimate their statistical characteristics. It is found that the sensitivity of all methods to Gaussian additive noise is higher than that of uniform one. We show that processes with long-term correlation react more actively to the additive amplitude noise then processes with short-term correlation. The influence of Hurst exponent value for the processes with long-term correlation is expressed for the coefficients S and C. The influence of correlation time is demonstrated for the coefficients S and СЕ. Our results may be useful in investigations of the mutual dynamics of two processes belonging to the considered types. Функционирование сложных систем возможно характеризовать совместными статистическими характеристиками порождаемых этими системами сигналов. Рассмотрены три подхода к оцениванию стабильности взаимного поведения двух тестовых процессов. Первый подход основан на расчете коэф­фициента фазовой синхронизации (КФС) между процессами. Второй метод базируется на определении взаимной условной энтропии (ВУЭ) процессов. Согласно третьему методу для оценивания стабильности взаимной динамики процессов используется среднее значение функции когерентности (ФК). Исследована чувствительность указанных методов к аддитивной амплитудной расстройке между процессами. Рас­ смотрены два типа процессов: с кратковременной зависимостью и заданным временем корреляции (ВК) и с долговременной зависимостью, определяемой значением показателя Херста. В исследованиях генерирова­лись две копии процесса с известными корреляционными свойствами. Затем в одну из копий вносилась ад­дитивная амплитудная помеха с независимыми отсчетами, подчиняющимися равномерному или нормаль­ ному распределению с одинаковой дисперсией. Для каждого типа помехи и каждого значения ее интенсив­ности оценивались статистические характеристики КФС, ВУЭ и ФК. Выявлено, что чувствительность рассмотренных методов к нормально распределенной расстройке выше, чем к равномерной. При этом процессы с долговременной зависимостью активнее реагируют на аддитивную амплитудную расстройку, чем процессы с кратковременной зависимостью. Влияние показателя Херста для процессов с долговременной зависимостью выражено для КФС и ФК. ВК процессов с кратковременной зависимостью влияет на КФС и ВУЭ. Полученные результаты позволяют обоснованно выбрать необходимый метод анализа взаимной динамики процессов, принадлежащий к рассмотренным в настоящей статье типам.

Interplay of non-linear elasticity and dislocation-induced superfluidity in solid Helium-4

The mechanism of the roughening induced partial depinning of gliding dislocations from Helium-3 impurities is proposed as an alternative to the standard "boiling off". We give a strong argument that Helium-3 remains bound to dislocations even at large temperatures due to very long equilibration times. A scenario leading to the similarity between elastic and superfluid responses of solid Helium-4 is also discussed. Its main ingredient is a strong suppression of the superfluidity along dislocation cores by dislocation kinks (D. Aleinikava, et. al., arXiv:0812.0983). These kinks, on one hand, determine the temperature and Helium-3 dependencies of the generalized shear modulus and, on the other hand, control the superfluid response. Several proposals for theoretical and experimental studies of solid Helium-4 are suggested.Comment: final version accepted to the special JLTP issue on Supersolid, 16 pages, 6 figures: typos corrected, more explanations give