296 research outputs found
STARE velocity at large flow angles: is it related to the ion acoustic speed?
International audienceThe electron drift and ion-acoustic speed in the E region inferred from EISCAT measurements are compared with concurrent STARE radar velocity data to investigate a recent hypothesis by Bahcivan et al. (2005), that the electrojet irregularity velocity at large flow angles is simply the product of the ion-acoustic speed and the cosine of an angle between the electron flow and the irregularity propagation direction. About 3000 measurements for flow angles of 50Β°?70Β° and electron drifts of 400?1500 m/s are considered. It is shown that the correlation coefficient and the slope of the best linear fit line between the predicted STARE velocity (based solely on EISCAT data and the hypothesis of Bahcivan et al. (2005)) and the measured one are both of the order of ~0.4. Velocity predictions are somewhat better if one assumes that the irregularity phase velocity is the line-of-sight component of the EΓB drift scaled down by a factor ~0.6 due to off-orthogonality of irregularity propagation (nonzero effective aspect angles of STARE observations)
Volume cross section of auroral radar backscatter and RMS plasma fluctuations inferred from coherent and incoherent scatter data: a response on backscatter volume parameters
Norway and Finland STARE radar measurements in the eastward auroral
electrojet are combined with EISCAT CP-1 measurements of the electron
density and electric field vector in the common scattering volume to
investigate the variation of the auroral radar volume cross section (VCS)
with the flow angle of observations (radar look direction with respect to
the <I><B>E</B></I>×<I><B>B</I></B> electron drift). The data set available consists of ~6000 points
for flow angles of 40β85Β° and electron drifts between 500
and 2000 m s<sup>β1</sup>. The EISCAT electron density <I>N(h)</I>-profile data are used
to estimate the effective electron density, aspect angle and thickness of
the backscattering layer. It is shown that the flow angle variation of the
VCS is rather weak, only ~5 dB within the range of the considered
flow angles. The VCS values themselves respond almost linearly to the square
of both the electron drift velocity magnitude and the effective electron
density. By adopting the inferred shape of the VCS variation with the flow
angle and the VCS dependence upon wavelength, the relative amplitude of
electrostatic electron density fluctuations over all scales is estimated.
Inferred values of 2β4 percent react nearly linearly to the electron drift
velocity in the range of 500β1000 m s<sup>β1</sup> but the rate of increase slows
down at electron drifts >1000 m s<sup>β1</sup> and density fluctuations of ~5.5
percent due to, perhaps, progressively growing nonlinear wave losses
Π Π²ΠΎΠΏΡΠΎΡΡ ΠΎ ΡΡΠΈΡ ΠΈΠ½Π΅Π»Π»ΠΎΡΠΊΠΎΠΏΠΈΠΈ Π±ΠΎΡΠΎΠ²ΠΎΠΉ Π΄ΠΈΡΠΈ
The purpose of the research is analyzing ways and factors of trichinellosis causative agent Trichinella pseudospiralis transmitted in the Russian Federation. Materials and methods. The main trichinellosis monitoring stages, methods of veterinary and sanitary examination for trichinellosis, and parameters for neutralization of the pathogen are given. Results and discussion. The most likely circulation patterns of trichinellosis pathogen T. pseudospiralis in natural and synanthropic biocenoses, and the key links that ensure the activity of infection foci are presented.Π¦Π΅Π»Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ β Π°Π½Π°Π»ΠΈΠ· ΠΏΡΡΠ΅ΠΉ ΠΈ ΡΠ°ΠΊΡΠΎΡΠΎΠ² ΠΏΠ΅ΡΠ΅Π΄Π°ΡΠΈ Π²ΠΎΠ·Π±ΡΠ΄ΠΈΡΠ΅Π»Ρ ΡΡΠΈΡ
ΠΈΠ½Π΅Π»Π»Π΅Π·Π° Trichinella pseudospiralis Π² Π ΠΎΡΡΠΈΠΉΡΠΊΠΎΠΉ Π€Π΅Π΄Π΅ΡΠ°ΡΠΈΠΈ. ΠΠ°ΡΠ΅ΡΠΈΠ°Π»Ρ ΠΈ ΠΌΠ΅ΡΠΎΠ΄Ρ. ΠΡΠΈΠ²Π΅Π΄Π΅Π½Ρ ΠΎΡΠ½ΠΎΠ²Π½ΡΠ΅ ΡΡΠ°ΠΏΡ ΠΌΠΎΠ½ΠΈΡΠΎΡΠΈΠ½Π³Π° ΡΡΠΈΡ
ΠΈΠ½Π΅Π»Π»Π΅Π·Π°, ΠΌΠ΅ΡΠΎΠ΄Ρ Π²Π΅ΡΠ΅ΡΠΈΠ½Π°ΡΠ½ΠΎ-ΡΠ°Π½ΠΈΡΠ°ΡΠ½ΠΎΠΉ ΡΠΊΡΠΏΠ΅ΡΡΠΈΠ·Ρ Π½Π° ΡΡΠΈΡ
ΠΈΠ½Π΅Π»Π»Π΅Π· ΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡ ΠΎΠ±Π΅Π·Π²ΡΠ΅ΠΆΠΈΠ²Π°Π½ΠΈΡ Π²ΠΎΠ·Π±ΡΠ΄ΠΈΡΠ΅Π»Ρ. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈ ΠΎΠ±ΡΡΠΆΠ΄Π΅Π½ΠΈΠ΅. ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ Π½Π°ΠΈΠ±ΠΎΠ»Π΅Π΅ Π²Π΅ΡΠΎΡΡΠ½ΡΠ΅ ΡΡ
Π΅ΠΌΡ ΡΠΈΡΠΊΡΠ»ΡΡΠΈΠΈ Π²ΠΎΠ·Π±ΡΠ΄ΠΈΡΠ΅Π»Ρ ΡΡΠΈΡ
ΠΈΠ½Π΅Π»Π»Π΅Π·Π° T. pseudospiralis Π² ΠΏΡΠΈΡΠΎΠ΄Π½ΠΎΠΌ ΠΈ ΡΠΈΠ½Π°Π½ΡΡΠΎΠΏΠ½ΠΎΠΌ Π±ΠΈΠΎΡΠ΅Π½ΠΎΠ·Π°Ρ
, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΎΡΠ½ΠΎΠ²Π½ΡΠ΅ Π·Π²Π΅Π½ΡΡ, ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°ΡΡΠΈΠ΅ ΡΡΠ½ΠΊΡΠΈΠΎΠ½ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΠΎΡΠ°Π³ΠΎΠ² ΠΈΠ½Π²Π°Π·ΠΈΠΈ
Sphere rolling on the surface of a cone
We analyse the motion of a sphere that rolls without slipping on a conical
surface having its axis in the direction of the constant gravitational field of
the Earth. This nonholonomic system admits a solution in terms of quadratures.
We exhibit that the only circular of the system orbit is stable and furthermore
show that all its solutions can be found using an analogy with central force
problems. We also discuss the case of motion with no gravitational field, that
is, of motion on a freely falling cone.Comment: 12 pages, 2 figures, to be published in Eur J Phy
Instability and Chaos in Non-Linear Wave Interaction: a simple model
We analyze stability of a system which contains an harmonic oscillator
non-linearly coupled to its second harmonic, in the presence of a driving
force. It is found that there always exists a critical amplitude of the driving
force above which a loss of stability appears. The dependence of the critical
input power on the physical parameters is analyzed. For a driving force with
higher amplitude chaotic behavior is observed. Generalization to interactions
which include higher modes is discussed.
Keywords: Non-Linear Waves, Stability, Chaos.Comment: 16 pages, 4 figure
Morphological and functional characteristics of Trichinella sp. larvae in bears and badgers in the Kirov Region
The purpose of the research is study of morphological and functional characteristics of Trichinella sp. larvae in bears and badgers in the Kirov Region.Materials and methods. The compressor trichinelloscopy (CT) method was used to study 72 sections of muscle tissue samples (in accordance with the Guidelines "Prevention of helminthiasis transmitted through meat and meat products" dated September 23, 1996) from animals obtained during scientific culling. The sections were prepared from the diaphragmatic peduncle muscles and the diaphragm of bears and badgers along the muscle fibers, and placed in the compressorium. The sections were then transferred to glass slides, and provisional slides were prepared and examined using various magnifications (Γ 8, Γ 20, Γ 40). Morphometric measurements were performed using a microscope at Γ 40 magnification, then the capsule index was calculated. Digestion (peptolysis) in artificial gastric juice was performed according to the P. A. Vladimirovaβs method modified by A. V. Uspensky and F. Skvortsova after the test samples were placed in various temperature conditions from 5 to -18 Β°C, and the parameters of both animal species were compared. The viability of Trichinella sp. larvae was evaluated in a Petri dish in saline at a room temperature. Morphological changes were recorded in the larvae structure (coiled larvae against the total number of isolated, coiled and stretched larvae) and their mobility.Results and discussion. We studied badgers and bears infected by Trichinella spiralis larvae in the Kirov Region. The Trichinella sp. larvae were found in all examined sections of the infected animals. The infection intensity was higher in the badger than the bear and amounted to 218Β±79.5 larvae per 1 g of muscle, while it was 115Β±28.5 in the bear. The stated above is explained by the fact that the badger eats carrion more often, and typically visits spontaneous dumps. For postmortem diagnosis of trichinellosis in the obtained bears and badgers, we can use trichinelloscopy and peptolysis methods which are aimed at detecting infection sources and preventing zoonosis in humans
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