1,311 research outputs found
Frequency and Phase Synchronization in Neuromagnetic Cortical Responses to Flickering-Color Stimuli
In our earlier study dealing with the analysis of neuromagnetic responses
(magnetoencephalograms - MEG) to flickering-color stimuli for a group of
control human subjects (9 volunteers) and a patient with photosensitive
epilepsy (a 12-year old girl), it was shown that Flicker-Noise Spectroscopy
(FNS) was able to identify specific differences in the responses of each
organism. The high specificity of individual MEG responses manifested itself in
the values of FNS parameters for both chaotic and resonant components of the
original signal. The present study applies the FNS cross-correlation function
to the analysis of correlations between the MEG responses simultaneously
measured at spatially separated points of the human cortex processing the
red-blue flickering color stimulus. It is shown that the cross-correlations for
control (healthy) subjects are characterized by frequency and phase
synchronization at different points of the cortex, with the dynamics of
neuromagnetic responses being determined by the low-frequency processes that
correspond to normal physiological rhythms. But for the patient, the frequency
and phase synchronization breaks down, which is associated with the suppression
of cortical regulatory functions when the flickering-color stimulus is applied,
and higher frequencies start playing the dominating role. This suggests that
the disruption of correlations in the MEG responses is the indicator of
pathological changes leading to photosensitive epilepsy, which can be used for
developing a method of diagnosing the disease based on the analysis with the
FNS cross-correlation function.Comment: 21 pages, 14 figures; submitted to "Laser Physics", 2010, 2
Measurement of low turbulence levels with a thermoanemometer
The trend for decreasing the drag of aircraft is retention of laminar flow in the boundary layer over a large portion of the surface. The laminar boundary layer was studied in a low turbulence wind tunnel for low subsonic velocities. The method used and results of measurements of very low levels of turbulence are presented. Measurements were performed by a constant-resistance thermoanemometer
Calculation of equatorial currents
Many calculations of the stationary and seasonal currents in the nonequatorial regions of the oceans have been done using an earlier model published by Sarkisyan (1969). The references list several new publications in this series (Bulatov et al.; Demin, 1975). The detailed analysis and survey of the diagnostic calculations were published recently in English (Sarkisyan, 1977)...
Towards portable muography with small-area, gas-tight glass Resistive Plate Chambers
Imaging techniques that use atmospheric muons, collectively named under the
neologism "muography", have seen a tremendous growth in recent times, mainly
due to their diverse range of applications. The most well-known ones include
but are not limited to: volcanology, archaeology, civil engineering, nuclear
reactor monitoring, nuclear waste characterization, underground mapping, etc.
These methods are based on the attenuation or deviation of muons to image large
and/or dense objects where conventional techniques cannot work or their use
becomes challenging.
In this context, we have constructed a muography telescope based on "mini
glass-RPC planes" following a design similar to the glass-RPC detectors
developed by the CALICE Collaboration and used by the TOMUVOL experiment in the
context of volcano radiography, but with smaller active area (16 16
cm). The compact size makes it an attractive choice with respect to other
detectors previously employed for imaging on similar scales. An important
innovation in this design is that the detectors are sealed. This makes the
detector more portable and solves the usual safety and logistic issues for gas
detectors operated underground and/or inside small rooms. This paper provides
an overview on our guiding principles, the detector development and our
operational experiences. Drawing on the lessons learnt from the first
prototype, we also discuss our future direction for an improved second
prototype, focusing primarily on a recently adopted serigraphy technique for
the resistive coating of the glass plates.Comment: 8 pages, 7 figures, XV Workshop on Resistive Plate Chambers and
Related Detectors (RPC2020
Application of probability methods to research of one type of exotic options in diffusion model (B, S)- of the financial market
The decision of optimum hedging problem for the European options of purchase and sale of the exotic type when possible payments on options are limited by the set value is resulted. The formulas defining costs of options and also evolution in time of portfolios and capitals, i. e. hedging strategy and corresponding to them are obtained. Some properties of decisions are investigated
Proton-He elastic scattering at low energies
We present new accurate measurements of the differential cross section
and the proton analyzing power for proton-He
elastic scattering at various energies. A supersonic gas jet target has been
employed to obtain these low energy cross section measurements. The
distributions have been measured at = 0.99, 1.59,
2.24, 3.11, and 4.02 MeV. Full angular distributions of have been
measured at = 1.60, 2.25, 3.13, and 4.05 MeV. This set of
high-precision data is compared to four-body variational calculations employing
realistic nucleon-nucleon (NN) and three-nucleon (3N) interactions. For the
unpolarized cross section the agreement between the theoretical calculation and
data is good when a potential is used. The comparison between the
calculated and measured proton analyzing powers reveals discrepancies of
approximately 50% at the maximum of each distribution. This is analogous to the
existing `` Puzzle'' known for the past 20 years in nucleon-deuteron
elastic scattering.Comment: 22 pages, 9 figures, to be published in Physical Review C, corrected
reference 4
MAGNETIC SYSTEMS SIMULATION OF MAGNETOSTRICTIVE CONVERTERS OF LEVEL AND DENSITY IN ELCUT
The advantages of universal program packages, allowing to solve different types of field tasks are analized. It is proved that the simulation of the magnetic system of the magnetostrictive transducers of level and density in the ELCUT environment is reduced to the two-dimensional tasks solution - plane-parallel and axisymmetric. Issues of the magnetic system modeling of the magnetostrictive transducers of level and density of liquid environments using permanent magnets, in the program ELCUT are developed. Systematic constraints modeling the magnetic system of the magnetostrictive transducers of level and density in the ELCUT environment are revealed. The maps of the axial measurements of the interaction of magnets floats level and density of the brand UHDK40Т8АА. The measurements results of magnetic forces are grouped and graphically presented. The basic magnetic characteristics study results of a single annular magnet are partle given. A mathematical model of the ponderomotive forces of adjacent magnets of the magnetic systems MPUP the ELCUT environment is defined
Non-dissipative drag of superflow in a two-component Bose gas
A microscopic theory of a non-dissipative drag in a two-component superfluid
Bose gas is developed. The expression for the drag current in the system with
the components of different atomic masses, densities and scattering lengths is
derived. It is shown that the drag current is proportional to the square root
of the gas parameter. The temperature dependence of the drag current is studied
and it is shown that at temperature of order or smaller than the interaction
energy the temperature reduction of the drag current is rather small. A
possible way of measuring the drag factor is proposed. A toroidal system with
the drag component confined in two half-ring wells separated by two Josephson
barriers is considered. Under certain condition such a system can be treated as
a Bose-Einstein counterpart of the Josephson charge qubit in an external
magnetic field. It is shown that the measurement of the difference of number of
atoms in two wells under a controlled evolution of the state of the qubit
allows to determine the drag factor.Comment: 13 pages, 3 figures. This preprint is extended and substantially
revised variant of related preprint cond-mat/040456
Features of participants’s training for the worldskills competitions
In this paper, there are discussed questions and features of college’s students’s training for their participation in regional, national and world WorldSkills championships. It is describe that such training should rely not only on traditional Russian methods of preparing participants for professional competitions, but also on WorldSkills standardsРассматриваются вопросы и особенности подготовки студентов системы СПО к участию в региональных, национальных и мировых чемпионатах WorldSkills. Показано, что такая подготовка должна опираться не только на традиционные российские методики подготовки участников к профессиональным конкурсам, но и на стандарты WorldSkill
- …