Stationary patterns of coherence and incoherence in two-dimensional arrays of non-locally-coupled phase oscillators.

Recently, it has been shown that large arrays of identical oscillators with nonlocal coupling can have a remarkable type of solutions that display a stationary macroscopic pattern of coexisting regions with coherent and incoherent motions, often called chimera states. Here, we present a detailed numerical study of the appearance of such solutions in two-dimensional arrays of coupled phase oscillators. We discover a variety of stationary patterns, including circular spots, stripe patterns, and patterns of multiple spirals. Here, stationarity means that, for increasing system size, the locally averaged phase distributions tend to the stationary profile given by the corresponding thermodynamic limit equation.

Spectral properties of chimera states.

Chimera states are particular trajectories in systems of phase oscillators with nonlocal coupling that display a spatiotemporal pattern of coherent and incoherent motion. We present here a detailed analysis of the spectral properties for such trajectories. First, we study numerically their Lyapunov spectrum and its behavior for an increasing number of oscillators. The spectra demonstrate the hyperchaotic nature of the chimera states and show a correspondence of the Lyapunov dimension with the number of incoherent oscillators. Then, we pass to the thermodynamic limit equation and present an analytic approach to the spectrum of a corresponding linearized evolution operator. We show that, in this setting, the chimera state is neutrally stable and that the continuous spectrum coincides with the limit of the hyperchaotic Lyapunov spectrum obtained for the finite size systems.

Control of spatially patterned synchrony with multisite delayed feedback.

We present an analytical study describing a method for the control of spatiotemporal patterns of synchrony in networks of coupled oscillators. Delayed feedback applied through a small number of electrodes effectively induces spatiotemporal dynamics at minimal stimulation intensities. Different arrangements of the delays cause different spatial patterns of synchrony, comparable to central pattern generators (CPGs), i.e., interacting clusters of oscillatory neurons producing patterned output, e.g., for motor control. Multisite delayed feedback stimulation might be used to restore CPG activity in patients with incomplete spinal cord injury or gait ignition disorders.

[Study of the reproductive function in albino rats after inhalation of 4,4'-diaminodiphenyl ether of resorcin]. / Issledovanie reproduktivnoi funktsii belykh krys pri ingaliatsionnom vozdeistvii 4,4'-diaminodifenilovogo éfira resortsina.

The article contains experimental data on the morphofunctional state of gonads in male rats after chronic inhalation of diamine P, and on the state of embryogenesis after inhalant introduction of diamine P into pregnant rats in threshold-level concentrations. Results of the study revealed that, in chronic inhalant introduction at 29.3 and 4.2 mg/m3, diamine P demonstrated gonadotoxic properties, which was proved by the higher percentage of dead spermatozoa and spermatogonium diseases. The changes in the gonads' state reflected the pathological processes caused by diamine P in the animals due to the general toxicity properties of the substance. The embryotoxic effect of diamine P in inhalations at 5 mg/m3 (close to the threshold levels of total toxicity) was not statistically relevant.

[The dynamics of the griseofulvin levels in the blood and skin of guinea pigs during its combined use with alpha-tocopherol]. / Dinamika soderzhaniia grizeoful'vina v krovi i kozhe morskikh svinok pri ego kompleksnom primenenii s al'fa-tokoferolom.

Experiments with 120 guinea pigs have revealed that skin griseofulvin levels depend on blood griseofulvin level and reduce after a prolonged (for 3-4 weeks) administration of the antibiotic in a dose of 30 mg/kg. Reduction of P-450 system enzymes activities achieved with alpha-tocopherol slows down griseofulvin biotransformation rate and significantly elevates its blood serum and skin concentrations.

[Perinatal pathology and risk groups in postnatal ontogeny]. / Perinatal'naia patologiia i gruppy riska v postnatal'nom ontogeneze.

Perinatal pathology may become the cause of diseases in children and adults. Cardiovascular system of the foetus and placental vessels are examined in the toxicosis of the pregnancy, hypertension of pregnant mothers, immunological system and sex glands in large foetus, thyroid and sex glands of newborns. It is suggested that early atherosclerosis, myocardiopathy, sexual disturbances, endocrinopathy, immunodeficient states are consequences of pathological or "prepathological" development of certain organs and systems of the foetus.

[Morphologic changes in the ovary upon exposure to low temperatures (-196 degrees C) using cryoprotection]. / Morfologicheskie izmeneniia v iaichnike v usloviiakh nizkikh temperatur (-196 gradusov C) s primeneniem krioprotektsii.

The biological action of deep freezing (-196 degrees C) on the ovary with the purpose of establishing the possibility of using low temperatures for long-term storage of this tissue was studied. The use of polyethylene oxide of molecular weight 400 at an optimal concentration (20%) for freezing at a rate of 1 degree per minute to -8 degrees C, then 10 degrees/min to --196 degrees C permits to retain the functional activity of the ovary and restoration of its function after transplantation.