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 50°?70° 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 E×B 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>&times;<I><B>B</I></B> electron drift). The data set available consists of ~6000 points for flow angles of 40–85° and electron drifts between 500 and 2000 m s⁻¹. 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 2–4 percent react nearly linearly to the electron drift velocity in the range of 500–1000 m s⁻¹ but the rate of increase slows down at electron drifts >1000 m s⁻¹ and density fluctuations of ~5.5 percent due to, perhaps, progressively growing nonlinear wave losses

К вопросу о трихинеллоскопии боровой дичи

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.Цель исследований – анализ путей и факторов передачи возбудителя трихинеллеза Trichinella pseudospiralis в Российской Федерации. Материалы и методы. Приведены основные этапы мониторинга трихинеллеза, методы ветеринарно-санитарной экспертизы на трихинеллез и параметры обезвреживания возбудителя. Результаты и обсуждение. Представлены наиболее вероятные схемы циркуляции возбудителя трихинеллеза T. pseudospiralis в природном и синантропном биоценозах, а также основные звенья, обеспечивающие функционирование очагов инвазии

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 (× 8, × 20, × 40). Morphometric measurements were performed using a microscope at × 40 magnification, then the capsule index was calculated. Digestion (peptolysis) in artificial gastric juice was performed according to the P. A. Vladimirova’s method modified by A. V. Uspensky and F. Skvortsova after the test samples were placed in various temperature conditions from 5 to -18 °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 218±79.5 larvae per 1 g of muscle, while it was 115±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