Wave chaos in a randomly inhomogeneous waveguide: spectral analysis of the finite-range evolution operator.

The problem of sound propagation in a randomly inhomogeneous oceanic waveguide is considered. An underwater sound channel in the Sea of Japan is taken as an example. Our attention is concentrated on the domains of finite-range ray stability in phase space and their influence on wave dynamics. These domains can be found by means of the one-step Poincare map. To study manifestations of finite-range ray stability, we introduce the finite-range evolution operator (FREO) describing transformation of a wave field in the course of propagation along a finite segment of a waveguide. Carrying out statistical analysis of the FREO spectrum, we estimate the contribution of regular domains and explore their evanescence with increasing length of the segment. We utilize several methods of spectral analysis: analysis of eigenfunctions by expanding them over modes of the unperturbed waveguide, approximation of level-spacing statistics by means of the Berry-Robnik distribution, and the procedure used by A. Relano and coworkers [Relano et al., Phys. Rev. Lett. 89, 244102 (2002); Relano, Phys. Rev. Lett. 100, 224101 (2008)]. Comparing the results obtained with different methods, we find that the method based on the statistical analysis of FREO eigenfunctions is the most favorable for estimating the contribution of regular domains. It allows one to find directly the waveguide modes whose refraction is regular despite the random inhomogeneity. For example, it is found that near-axial sound propagation in the Sea of Japan preserves stability even over distances of hundreds of kilometers due to the presence of a shearless torus in the classical phase space. Increasing the acoustic wavelength degrades scattering, resulting in recovery of eigenfunction localization near periodic orbits of the one-step Poincaré map.

[Control of sex cycle functions in sheep using cloprostenol, an analog of prostaglandin F2a]. / Kontrolirane na polovotsiklichnite funktsii pri ovtsete s analoga na prostaglandin F2a-kloprostenol.

Studied was the synchronizing effect of the prostaglandin F2a analague - estrumate (ICI, England). with the Tsigai sheep. The investigations included observations on the clinical characteristics of the estrus, determination of the hormonal profile in naturally manifested estrus and in estrus induced with prostaglandin, and the conception rate with the first two successive estrus cycles along with the total conception. Estrumate was used twice ar a 9-day interval in a single dose of 125 mg, with a following programmed artificial insemination at the 48 h and the 72d hour after the second treatment. The conception rate with the first estrus of the ewes of the control and the test group was comparatively low - 41.3 and 30.4 per cent, and with the two successive cycles - 68.5 and 76.8 per cent, respectively. The total conception of the test group was 96.4 per cent as against 87.5 per cent of the control group. The studies on the content and dynamics of the basic hormones taking part in the endocrine regulation of the cycle functions in sheep with naturally manifested estrus and those with prostaglandine-unduced estrus did not show reliable differences in the hormonal profile. It was found that estrumate could successfully be used to synchronized the estrus cycle with the Tsigai sheep - a breed with pronounced conservatism' in the manifestation of cyclic functions.

[Estrus induction in sheep injected with colostrum at different phases of the sexual cycle]. / Indutsirane na estrus pri ovtse, inzhektirani s kolastra v razlichni fazi na poloviia tsikul.

Investigations on the mechanism of colostrum effect in sheep sex apparatus stimulation were carried out. The experiments included 57 sheep, 10 of them used as a check and the remaining 47 distributed in four treatment groups and injected with colostrum at various phases of the sex cycle. It was established that the effectiveness of injecting cow colostrum on sheep with the aim of inducing synchronous oestrus during the regular reproduction season depends on the sex cycle phase at which the injection takes place. The effectiveness is higher in case injection is performed during the second half of dioestrum. The induced synchronous oestrus of sheep following colostrum injection is equivalent to the normal.