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Human health electromagnetic safety is one of electromagnetic compatibility problem. Electromagnetic fields (EMF) different frequency ranges are human health risk factor: cardio-vascular diseases, cancer, congenital malformations, neurodegenerative diseses. The main principle of electromagnetic safety is hygienic regulation. EMF hygienic standardization in Russia is based on the results of hygienic, clinical-physiological, epidemiological and experimental studies. Hygienic norms are developed for discrete frequency ranges. The main discrepancy of Russian and international EMF hydienic standardization approaches is in concepts of "cumulative" or "acute" factor effects, correspondingly. Hence EMF hygienic norms in RF are time dependent, comprising a principle "protection by time". The progress in EMF hygienic safety problem solving is time dependent norms for frequencies from 3 Hz up to 10 kHz development, as well as attempt of near zone EMF adequate evaluation (for > 300 MHz frequency range) principles. [ABSTRACT FROM AUTHOR]

Longitudinal voltage values, induced by magnetic fields currents in parallel overhead transmission line are determined usually by derivative of Carson' integral equations. These equations application have broad "dead space" conditionally the spacing of transmission lines and ground conductivity that lead to great calculative error. The method of longitudinal voltage values induced by magnetic field in parallel overhead transmission lines calculation for any distance between lines is suggested with full coincidence with Carson' equation calculation (in work space) without "dead space" (with high calculation error). [ABSTRACT FROM AUTHOR]

A multifunctional semiconductor mirror that contains a saturable absorber based on quantum wells, a broadband reflector, and a Gires-Tournois interferometer that serves as a GVD compensator is designed and created. The mirror is fully characterized using the pump-probe technique with a subpicosecond resolution and the transmission and photoluminescence spectroscopy. The mirror that simultaneously executes the three functions and that is created in a single technological cycle provides stable mode-locking in the Nd3+:KGd(WO4)2 laser. [ABSTRACT FROM AUTHOR]

B chromosomes are often considered to be one of the most mysterious elements of karyotypes (Camacho, 2004). It is generally believed that mammalian B chromosomes do not contain any protein coding genes. The discovery of a conserved KIT gene in Canidae B chromosomes has changed this view. Here we performed analysis of sequences surrounding KIT in B chromosomes of the fox and raccoon dog. The presence of the RPL23A pseudogene was shown in canid B chromosomes. The 3′ end fragment of the KDR gene was found in raccoon dog B chromosomes. The size of the B-specific fragment homologous to the autosome fragment was estimated to be a minimum of 480 kbp in both species. The origin and evolution of B chromosomes in Canidae are discussed. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Possibilities for the control of the parameters of free-polarization decay (FPD), optical nutation, and photon echo (PE) using the dressing field are studied. Coherent transients are generated with the Stark switching technique and are detected in the radiation of the probe field polarized orthogonally to the dressing field. The evolution-operator technique is employed in the calculations. The experiments are performed at the R(4, 3) transition of the 0 ↔ 1 v3 13CH3F vibrational band with the radiation of a cw CO2 laser. It is theoretically and experimentally demonstrated that FPD and PE are suppressed upon an increase in the intensity of the dressing field. The observed shapes of the transient FPD and PE signals and their variations with the dressing field intensity are in qualitative agreement with the results of the calculations. [ABSTRACT FROM AUTHOR]

Three and four independent cell lines with limited pluripotency were obtained from the inner cell mass cells of blastocysts and primordial germ cells of common voles, respectively. The results of cytogenetic analysis suggest that all these lines originated from the embryos of F1Microtus rossiaemeridionalis × M. arvalis males and had a great number of near-triploid cells already during the early passages. The cells of these lines, like those of the inner cell mass, were characterized by the alkaline phosphatase activity. Nine independent cell lines were obtained as a result of hybridization of the mouse embryonic stem cells and vole splenocytes: eight lines and one line from hybridization with the M. kirgisorum and M. rossiaemeridionalis splenocytes, respectively. The cells of these lines expressed some properties of embryonic stem lines had a chromosome complement similar to the sum of two initial diploid sets of the mouse and vole. [ABSTRACT FROM AUTHOR]

Comparative chromosomal analysis is a powerful tool in the investigation of the mechanisms of chromosomal evolution. The accuracy of the analysis depends on the availability of region-specific markers to follow the fate of the particular chromosomal region through the evolution of species. We have assigned 12 unique sequences to the euchromatic part of the vole X chromosome, which serve as reliable markers of chromosomal segments. Together with region-specific libraries and GTG banding, these markers allow us to delineate the homologous regions of the X chromosomes in five species of the genus Microtus. We found that X chromosomes of these species differ by numerous rearrangements and all rearrangements are clustered at specific breakpoints. Moreover, these breakpoints were found to colocalise with repetitive and/or duplicated DNA sequences. We suggest that clusters of repeated and/or duplicated DNA sequences have played a crucial role in the formation of rearrangement hot spots during evolution of the X chromosome in the subgenus Microtus. Copyright © 2002 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The dynamic Stark effect on the as Q(5,4) transition of the 0 → 1 vibrational band of the &nu[sub 2] mode of ammonia [sup 15]NH[sub 3] was studied by the method of copropagating waves of radiation of two [sup 13]CO[sub 2] lasers operating at the R(18)[sub I] line. For waves with mutually orthogonal polarizations, which propagated in a waveguide cell, the intensity of the saturating radiation reached 225 W/cm², and the absorption line of the probing radiation had the form of a two-hump curve with a splitting that was consistent with the Rabi frequency for the ammonia transition being investigated. At the maximum intensity of the saturating radiation, complete transparency was observed at the center of the absorption line of [sup 15]NH[sub 3]. When identically polarized saturating and probing waves propagating in a cell at a small angle with respect to each other were used, the splitting was more weakly manifested. The effect of a spatial inhomogeneity of the optical fields on the shape of the line of saturated absorption is discussed. [ABSTRACT FROM AUTHOR]

Collisional relaxation in SF[sub 6] gas and its mixtures with He and Xe is studied by photon echo and stimulated photon echo methods from the standpoint of the possibility of identifying the contributions of different types of collisions. The nonexponential nature of the kinetic curve of the photon echo is clearly observed for pure SF[sub 6], it is weaker in the mixture SF[sub 6] + Xe, and it is virtually completely absent for high degrees of dilution of SF[sub 6] with helium. These features can be explained on the basis of estimates, made from experimental data, of the critical delay between the exciting pulses (for which the nonexponential behavior should be most strongly manifested). In pure SF[sub 6] it is possible to distinguish the contribution of the inelastic channel (rotational relaxation) and the contribution of weak collisions. To distinguish successfully the relaxation channels in mixtures with buffer gases a heavier buffer gas and a much better time resolution must be used. It is shown that data obtained on the orientation and alignment relaxation rates by the stimulated photon echo method can serve as an upper limit for the rates of inelastic processes which cannot be measured by the photon echo method. The combined use of photon echo and stimulated photon echo methods made it possible to obtain data on the cross sections for elastic and inelastic scattering of the collisional pairs SF[sub 6]-SF[sub 6], SF[sub 6]-Xe, and SF[sub 6]-He. [ABSTRACT FROM AUTHOR]

A stimulated photon echo technique with specially selected linear polarizations of the coherent resonant driver pulses is used to study depolarizing collisions in the molecular gas SF[sub 6] and in mixtures of it with buffer He and Xe. The collisional decay rates of the population, orientation, and alignment in an ensemble of gas particles are determined for the first time in a single experiment. These relaxation rates are measured as a function of the longitudinal translational velocities of the resonant particles. To within the experimental accuracy, no significant dependence of the collisional decay rates on the translational velocities of the particles was observed. This result confirms the conventional theoretical approach to depolarizing collisions. In pure SF[sub 6] the decay rates for the orientation and alignment were lower than the relaxation constant for collisions involving a change in the longitudinal velocity (elastic collisions) that is known from experimental observations of the ordinary photon echo. This means that only some of the elastic collisions participate in destroying the multipole moments of the levels. Evidence is found that the relaxation of the multipole moments created by polarized radiation in a resonant medium of molecular SF[sub 6] gas depends on j, the total angular momentum of the level. [ABSTRACT FROM AUTHOR]

It is proposed to apply a reflective interferometer in measurements of the spectral dependence of the phase of reflection of mirrors based on multilayer semiconductor nanostructures. The interferometer has been tested on the semiconductor mirror initiating the self-locking mode of a Nd3+: KGd(WO4)2 laser. The technique proposed can be applied in a wide wavelength range and has a higher sensitivity for measuring the phase characteristics in comparison with the conventional two-beam interferometers. [ABSTRACT FROM AUTHOR]

The kinetics of the reflectivity of semiconductor samples with multiple GaAs/AlGaAs quantum wells has been investigated by the pump-probe method with a resolution of 150 fs. Excitons of the E1 HH1 and E1 LH1 types manifest themselves in the kinetics of transient reflectivity spectra despite the high density of the photogenerated two-dimensional electron gas. Differences are revealed in the shape and kinetics of the transient reflectivity spectra of samples with different detuning of exciton transitions from the pump frequency. [ABSTRACT FROM AUTHOR]

A photon echo induced exclusively by collisions of ytterbium atoms with buffer gas atoms has been observed at a 0 ⟷ 1-type1 S 0(6 s 2)-3 P 1(6 s6 p) 174Yb transition. The polarization properties of a collision echo and the buffer gas density dependence of its intensity agree with theoretical predictions of a model of depolarizing collisions that takes into account the dependence of a relaxation matrix on the velocity of active particles. Thus, direct experimental evidence of the relaxation anisotropy due to depolarizing collisions has been obtained. [ABSTRACT FROM AUTHOR]