592 research outputs found
Renormalized theory of the ion cyclotron turbulence in magnetic field--aligned plasma shear flow
The analytical treatment of nonlinear evolution of the shear-flow-modified
current driven ion cyclotron instability and shear-flow-driven ion cyclotron
kinetic instabilities of magnetic field--aligned plasma shear flow is
presented. Analysis is performed on the base of the nonlinear dispersion
equation, which accounts for a new combined effect of plasma turbulence and
shear flow. It consists in turbulent scattering of ions across the shear flow
with their convection by shear flow and results in enhanced nonlinear
broadening of ion cyclotron resonances. This effect is found to lead to the
saturation of ion cyclotron instabilities as well as to the development of
nonlinear shear flow driven ion cyclotron instability. 52.35.RaComment: 21 page
Numerical simulation of high-current ion beam acceleration and charge compensation in magnet-isolated systems
Metal-insulator transition induced by 16O -18O oxygen isotope exchange in colossal negative magnetoresistance manganites
The effect of 16O-18O isotope exchange on the electric resistivity was
studied for (La(1-y)Pr(y))0.7Ca0.3MnO3 ceramic samples. Depending on y, this
mixed perovskite exhibited different types of low-temperature behavior ranging
from ferromagnetic metal (FM) to charge ordered (CO) antiferromagnetic
insulator. It was found that at y=0.75, the substitution of 16O by 18O results
in the reversible transition from a FM to a CO insulator at zero magnetic
field. The applied magnetic field (H >= 2 T) transformed the sample with 18O
again to the metallic state and caused the increase in the FM transition
temperature Tc of the 16O sample. As a result, the isotope shift of Tc at H = 2
T was as high as 63 K. Such unique sensitivity of the system to oxygen isotope
exchange, giving rise even to the metal-insulator transition, is discussed in
terms of the isotope dependence of the effective electron bandwidth which
shifts the balance between the CO and FM phases.Comment: 5 pages (RevTeX), 2 eps figures included, to appear in J. Appl. Phys.
83, (1998
Possibilities of using naftidrofuryl in the therapy of cerebrovascular diseases: Literature review and the authors’ observations
The efficacy of naftidrofuryl in treating cerebrovascular diseases is analyzed on the basis of a review of the Russian and foreign literature. Naftidrofuryl is a seroton 5-HT2 receptor antagonist and acts on brain energy metabolism mainly during hypoxia or ischemia. The results of preclinical studies proving the antispasmodic and neuroprotective properties of the drug and its capacity to normalize microcirculation in hypoxia are briefly considered. Experimental findings served as a basis for further studies of the efficacy of naftidrofuryl in patients with stroke, chronic cerebral ischemia, or vascular dementia. The use of naftidrofuryl (dusopharm) was demonstrated to statistically significantly enhance the efficiency of rehabilitation in post-stroke patients and to be followed by significant psychoemotional improvement. According to a Cochrane review, the naftidrofuryl-treated patients with vascular dementia showed a tendency towards better executive and cognitive functions, behavior, and mood. The drug was noted to have a positive effect on the health of patients with chronic cerebral ischemia.The authors provide the data of their trial of naftidrofuryl used in patients with dyscirculatory encephalopathy, which have confirmed its efficacy in this category of patients. The data available in the literature suggest that oral naftidrofuryl has a good tolerability and safety profile in patients with cerebrovascular diseases
Future teachers’ training for learners’ individual projects management
© 2016 by iSER, International Society of Educational Research.The relevance of the issue considered in the article concerning the training of future teachers in the higher education institution for learners’ project and research activity as an obligatory component of professional pedagogical education is caused by current trends of social development which sets new tasks for school – keen interest in exceptional and talented children, in the peculiarities of their abilities advancement in the course of education. The leading method of the designated research is the method of content and procedural modeling of higher education institution students vocational competences connected with the arrangement of learners’ project activity. The article contains the experience of future language and literature teachers’ methodical training content development to implement learners’ individual projects arrangement. The authors lay emphasis on the procedural component of future teacher’s vocational training – a step-by-step training aimed to model learners’ individual projects arrangement in the form of an educational project or educational research. The offered material may be useful for bachelors, masters, graduate students trained according to humanitarian programs approved for teachers’ training institutes, as well as for language and literature teachers
Semantic features of the phraseological units with the component light within the artistic discourse
Conduct lexical and semantic analysis on the concept light in the artistic discourse of postmodern fictio
Natural Afforestation on Abandoned Agricultural Lands during Post-Soviet Period: A Comparative Landsat Data Analysis of Bordering Regions in Russia and Belarus
Remote monitoring of natural afforestation processes on abandoned agricultural lands is crucial for assessments and predictions of forest cover dynamics, biodiversity, ecosystem functions and services. In this work, we built on the general approach of combining satellite and field data for forest mapping and developed a simple and robust method for afforestation dynamics assessment. This method is based on Landsat imagery and index-based thresholding and specifically targets suitability for limited field data. We demonstrated method’s details and performance by conducting a case study for two bordering districts of Rudnya (Smolensk region, Russia) and Liozno (Vitebsk region, Belarus). This study area was selected because of the striking differences in the development of the agrarian sectors of these countries during the post-Soviet period (1991-present day). We used Landsat data to generate a consistent time series of five-year cloud-free multispectral composite images for the 1985–2020 period via the Google Earth Engine. Three spectral indices, each specifically designed for either forest, water or bare soil identification, were used for forest cover and arable land mapping. Threshold values for indices classification were both determined and verified based on field data and additional samples obtained by visual interpretation of very high-resolution satellite imagery. The developed approach was applied over the full Landsat time series to quantify 35-year afforestation dynamics over the study area. About 32% of initial arable lands and grasslands in the Russian district were afforested by the end of considered period, while the agricultural lands in Belarus’ district decreased only by around 5%. Obtained results are in the good agreement with the previous studies dedicated to the agricultural lands abandonment in the Eastern Europe region. The proposed method could be further developed into a general universally applicable technique for forest cover mapping in different growing conditions at local and regional spatial levels
Analysis of model for assessing the road train movement stability
In this paper, we conduct a mathematical analysis of the model of ensuring the road trains movement stability by changing the design of coupling devices to determine the critical characteristic parameters of the road trains, which result in the loss of en-route directional stability under external action. The concept of the model was to separate the process of yawing of the road trains and its elements (due to external perturbing action) on the highway into several typical stages. The main parameters of the stages (the displacement amplitude and rotation angle of the road trains elements in relation to the driving direction) were determined based on the initial conditions of the road trains movement, the force and duration of the external action. The most dangerous areas of external action application to the road trains were determined in this paper. The maximum permissible exposure limit should not exceed 0.5-1.0% of the road trains trailer momentum, with duration having the greater effect than the amount of impact. The results obtained can be used in mechanical engineering to improve the road trains performance. © Published under licence by IOP Publishing Ltd
A review and test of predictive models for the bioaccumulation of 5 radiostrontium in fish. 6 7
Natural Afforestation on Abandoned Agricultural Lands during Post-Soviet Period: A Comparative Landsat Data Analysis of Bordering Regions in Russia and Belarus
Remote monitoring of natural afforestation processes on abandoned agricultural lands is crucial for assessments and predictions of forest cover dynamics, biodiversity, ecosystem functions and services. In this work, we built on the general approach of combining satellite and field data for forest mapping and developed a simple and robust method for afforestation dynamics assessment. This method is based on Landsat imagery and index-based thresholding and specifically targets suitability for limited field data. We demonstrated method’s details and performance by conducting a case study for two bordering districts of Rudnya (Smolensk region, Russia) and Liozno (Vitebsk region, Belarus). This study area was selected because of the striking differences in the development of the agrarian sectors of these countries during the post-Soviet period (1991-present day). We used Landsat data to generate a consistent time series of five-year cloud-free multispectral composite images for the 1985–2020 period via the Google Earth Engine. Three spectral indices, each specifically designed for either forest, water or bare soil identification, were used for forest cover and arable land mapping. Threshold values for indices classification were both determined and verified based on field data and additional samples obtained by visual interpretation of very high-resolution satellite imagery. The developed approach was applied over the full Landsat time series to quantify 35-year afforestation dynamics over the study area. About 32% of initial arable lands and grasslands in the Russian district were afforested by the end of considered period, while the agricultural lands in Belarus’ district decreased only by around 5%. Obtained results are in the good agreement with the previous studies dedicated to the agricultural lands abandonment in the Eastern Europe region. The proposed method could be further developed into a general universally applicable technique for forest cover mapping in different growing conditions at local and regional spatial levels
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