NEUROPROTECTIVE AND MNEMOTROPIC EFFECTS OF SOMNIFACIENTS AT DIFFUSE AXONAL INJURY

Neuroprotective features of somnifacients were studied in animals with diffuse axonal injuries (DAI). It was established that in the presence of DAI Zopiclone had evident anticonvulsant and slight antihypoxic actions mainly in early period of trauma. Zolpidem had evident anti-ischemic action, slight antihypoxic and moderate anticonvulsant actions in late posttraumatic period. Zopiclone and Золпидем significantly restored short-term and long-term memory after diffuse axonal injuries

Combined effect of coherent Z exchange and the hyperfine interaction in atomic PNC

The nuclear spin-dependent parity nonconserving (PNC) interaction arising from a combination of the hyperfine interaction and the coherent, spin-independent, PNC interaction from Z exchange is evaluated using many-body perturbation theory. For the 6s-7s transition in 133Cs, we obtain a result that is about 40% smaller than that found previously by Bouchiat and Piketty [Phys. Lett. B 269, 195 (1991)]. Applying this result to 133Cs, leads to an increase in the experimental value of nuclear anapole moment and exacerbates differences between constraints on PNC meson coupling constants obtained from the Cs anapole moment and those obtained from other nuclear parity violating experiments. Nuclear spin-dependent PNC dipole matrix elements, including contributions from the combined weak-hyperfine interaction, are also given for the 7s-8s transition in 211Fr and for transitions between ground-state hyperfine levels in K, Rb, Cs, Ba+, Au, Tl, Fr, and Ra+.Comment: Revtex4 preprint 19 pages 4 table

Observation of modified radiative properties of cold atoms in vacuum near a dielectric surface

We have observed a distance-dependent absorption linewidth of cold $^{87}$Rb atoms close to a dielectric-vacuum interface. This is the first observation of modified radiative properties in vacuum near a dielectric surface. A cloud of cold atoms was created using a magneto-optical trap (MOT) and optical molasses cooling. Evanescent waves (EW) were used to observe the behavior of the atoms near the surface. We observed an increase of the absorption linewidth with up to 25% with respect to the free-space value. Approximately half the broadening can be explained by cavity-quantum electrodynamics (CQED) as an increase of the natural linewidth and inhomogeneous broadening. The remainder we attribute to local Stark shifts near the surface. By varying the characteristic EW length we have observed a distance dependence characteristic for CQED.Comment: 6 pages, 6 figures, some minor revision

Correlated many-body treatment of Breit interaction with application to cesium atomic properties and parity violation

Corrections from Breit interaction to basic properties of atomic 133Cs are determined in the framework of third-order relativistic many-body perturbation theory. The corrections to energies, hyperfine-structure constants, off-diagonal hyperfine 6S-7S amplitude, and electric-dipole matrix elements are tabulated. It is demonstrated that the Breit corrections to correlations are comparable to the Breit corrections at the Dirac-Hartree-Fock level. Modification of the parity-nonconserving (PNC) 6S-7S amplitude due to Breit interaction is also evaluated; the resulting weak charge of $^{133}$Cs shows no significant deviation from the prediction of the standard model of elementary particles. The neutron skin correction to the PNC amplitude is also estimated to be -0.2% with an error bound of 30% based on the analysis of recent experiments with antiprotonic atoms. The present work supplements publication [A. Derevianko, Phys. Rev. Lett. 85, 1618 (2000)] with a discussion of the formalism and provides additional numerical results and updated discussion of parity violation.Comment: 16 pages; 5 figs; submitted to Phys. Rev.

K-shell photoionization of ground-state Li-like boron ions [B2+^{2+}]: Experiment and Theory

Absolute cross sections for the K-shell photoionization of ground-state Li-like boron [B$^{2+}$(1s$^2$2s $^2$S)] ions were measured by employing the ion-photon merged-beams technique at the Advanced Light Source synchrotron radiation facility. The energy ranges 197.5--200.5 eV, 201.9--202.1 eV of the [1s(2s\,2p)$^3$P]$^2$P${\rm ^o}$ and [1s(2s\,2p)$^1$P] $^2$P${\rm ^o}$ resonances, respectively, were investigated using resolving powers of up to 17\,600. The energy range of the experiments was extended to about 238.2 eV yielding energies of the most prominent [1s(2$\ell$\,n$\ell^{\prime}$)]$^2$P$^o$ resonances with an absolute accuracy of the order of 130 ppm. The natural linewidths of the [1s(2s\,2p)$^3$P] $^2$P${\rm ^o}$ and [1s(2s\,2p)$^1$P] $^2$P${\rm ^o}$ resonances were measured to be $4.8 \pm 0.6$ meV and $29.7 \pm 2.5$ meV, respectively, which compare favourably with theoretical results of 4.40 meV and 30.53 meV determined using an intermediate coupling R-matrix method.Comment: 6 figures and 2 table

Flanking monomer repeats define lower context complexity of sites containing single nucleotide polymorphisms in the human genome

We have investigated a mutation frequency within the human genome for the set of known single nucleotide polymorphisms (SNPs) from the “1000 genomes” project. We have developed and applied novel statistical computational methods to analyze genetic text based on its complexity. A complexity profiling in a sliding window is applied to the sites containing single nucleotide polymorphisms within the human genome. A local decrease in text complexity level in SNP-containing sites has been shown. Analysis of the complexity profiles for SNPcontaining sites shows that flanking monomer repeats define a lower context complexity of sites containing SNPs within the human genome. An effect of local decrease in text complexity in SNP-containing sites is confirmed by analysis of polymorphisms in the rat and mouse genomes. We have found context differences between coding and regulatory sequences. These differences reflect a complexity of SNP-containing loci. The changes in point mutation frequency were shown previously for microsatellite containing sequences. Using enhanced mathematical tools and larger data sets this work shows enrichment of polytracks and simple sequence repeats in local genome surroundings of SNP containing sites. We have found high-frequency oligonucleotides within genomic regions containing SNPs. Such oligonucleotides are related to nucleotide polytracks. The presence of poly-A tracks might be associated with an increased probability of double helix DNA breaks around mutable loci and following fixation of nucleotide changes. The complexity estimates were computed using a previously developed program tool. This tool allows for both (i) complexity estimation of phased samples, and (ii) rapid and effective identification of the frequency spectrum of oligonucleotides with fixed lengths, and a comparison of oligonucleotide frequencies in different sample

Long-range interactions of copper and silver atoms with hydrogen, helium, and rare-gas atoms

Dispersion interactions of the ground and resonantly excited states of Cu and Ag with a number of buffer gases are determined. The valence excitation spectrum was calculated by diagonalizing a semiempirical Hamiltonian in a large-dimension single-electron basis. The core made a significant contribution to the C6 and C8 dispersion coefficients for both copper and silver. Oscillator strengths and static scalar and tensor polarizabilities are given for some of the low-lying states

Theory and applications of atomic and ionic polarizabilities

Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are predominantly due to the polarization interaction. An imperfect knowledge of atomic polarizabilities is presently looming as the largest source of uncertainty in the new generation of optical frequency standards. Accurate polarizabilities for the group I and II atoms and ions of the periodic table have recently become available by a variety of techniques. These include refined many-body perturbation theory and coupled-cluster calculations sometimes combined with precise experimental data for selected transitions, microwave spectroscopy of Rydberg atoms and ions, refractive index measurements in microwave cavities, ab initio calculations of atomic structures using explicitly correlated wave functions, interferometry with atom beams, and velocity changes of laser cooled atoms induced by an electric field. This review examines existing theoretical methods of determining atomic and ionic polarizabilities, and discusses their relevance to various applications with particular emphasis on cold-atom physics and the metrology of atomic frequency standards.Comment: Review paper, 44 page