Gamma-ray Flares and VLBI Outbursts of Blazars

A model is developed for the time dependent electromagnetic - radio to gamma-ray - emission of active galactic nuclei, specifically, the blazars, based on the acceleration and creation of leptons at a propagating discontinuity or {\it front} of a Poynting flux jet. The front corresponds to a discrete relativistic jet component as observed with very-long-baseline-interferometry (VLBI). Equations are derived for the number, momentum, and energy of particles in the front taking into account synchrotron, synchrotron-self-Compton (SSC), and inverse-Compton processes as well as photon-photon pair production. The apparent synchrotron, SSC, and inverse-Compton luminosities as functions of time are determined. Predictions of the model are compared with observations in the gamma, optical and radio bands. The delay between the high-energy gamma-ray flare and the onset of the radio is explained by self-absorption and/or free-free absorption by external plasma. Two types of gamma-ray flares are predicted depending on pair creation in the front.Comment: 11 pages, submitted to ApJ. 10 figures can be obtained from R. Lovelace by sending postal address to [email protected]

Conductivity, weak ferromagnetism and charge instability in α−MnS\alpha-MnS single crystal

The temperature dependence of resistivity, magnetization and electron-spin resonance of the $\alpha- MnS$ single crystal were measured in temperature range of $5 K < T < 550 K$. Magnetization hysteresis in applied magnetic field up to 0.7 T at $T=5 K, 77 K, 300 K$, irreversible temperature behavior of magnetization and resistivity were found . The obtained data were explained in terms of degenerate tight binding model using random phase approximation. The contribution of holes in $t_{2g}$ and $e_g$ bands of manganese ions to the conductivity, optical absorbtion spectra and charge instability in $\alpha -MnS$ were studied. Charge susceptibility maxima resulted from the competition of the on-site Coulomb interaction between the holes in different orbitals and small hybridization of sub-bands were calculated at $T=160 K, 250 K, 475 K$.Comment: 6 pages, 12 figure

Relativistic dynamical polarizability of hydrogen-like atoms

Using the operator representation of the Dirac Coulomb Green function the analytical method in perturbation theory is employed in obtaining solutions of the Dirac equation for a hydrogen-like atom in a time-dependent electric field. The relativistic dynamical polarizability of hydrogen-like atoms is calculated and analysed

Efficiency of local therapy with the use of a new preparation for oral care at periodontitis in the course of hyperpeptic gastritis after tobacco smoke intoxication

Periodontal diseases, arising against a background of stomach pathology at tobacco addiction remain an acute problem of modern dentistry. The aim of the work is an experimental study of efficiency of application of the new preparation for oral care during treatment of periodontitis simulated against a background of hyperpeptic gastritis under conditions of intoxication by tobacco smoke. At the first stage all experimental animals were divided into 4 groups: І - intact, II - with simulated periodontitis, III - with simulated periodontitis against a background of simulated hyperpeptic gastritis, IV - with simulated periodontitis against a background of hyperpeptic gastritis under conditions of tobacco smoking. Biochemical researches at periodontitis in rats were conducted for determination of influencing stomach pathology and tobacco smoke. On the II stage efficiency of local therapy was studied with the use of the new preparation for oral care and a comparator agent.Results: At experimental periodontitis against a background of hyperpeptic gastritis under conditions of smoking the considerable changes in periodontal tissues typical for the inflammatory process develop. The local therapy at rats with the use of the new preparation resulted in accelerating removing harmful influence of damaging factors and restoring the state of periodontal tissues, than in case of application of the comparator agent. The efficiency of the new preparation consists in normalizing influence on processes of lipid peroxidation, inflammation and activation of the protective systems of oral cavity during periodontitis which arises up against a background of hyperpeptic gastritis

Particle Acceleration and Magnetic Dissipation in Relativistic Current Sheet of Pair Plasmas

We study linear and nonlinear development of relativistic and ultrarelativistic current sheets of pair plasmas with antiparallel magnetic fields. Two types of two-dimensional problems are investigated by particle-in-cell simulations. First, we present the development of relativistic magnetic reconnection, whose outflow speed is an order of the light speed c. It is demonstrated that particles are strongly accelerated in and around the reconnection region, and that most of magnetic energy is converted into "nonthermal" part of plasma kinetic energy. Second, we present another two-dimensional problem of a current sheet in a cross-field plane. In this case, the relativistic drift kink instability (RDKI) occurs. Particle acceleration also takes place, but the RDKI fast dissipates the magnetic energy into plasma heat. We discuss the mechanism of particle acceleration and the theory of the RDKI in detail. It is important that properties of these two processes are similar in the relativistic regime of T > mc^2, as long as we consider the kinetics. Comparison of the two processes indicates that magnetic dissipation by the RDKI is more favorable process in the relativistic current sheet. Therefore the striped pulsar wind scenario should be reconsidered by the RDKI.Comment: To appear in ApJ vol. 670; 60 pages, 27 figures; References and typos are fixe

Relativistic dynamical polarizability of hydrogen-like atoms

Using the operator representation of the Dirac Coulomb Green function the analytical method in perturbation theory is employed in obtaining solutions of the Dirac equation for a hydrogen-like atom in a time-dependent electric field. The relativistic dynamical polarizability of hydrogen-like atoms is calculated and analysed.Comment: 15 pages, 3 figures (not included, but hard copies are available upon request

Joint voltammetric determination of dopamine and uric acid

Electrocatalytic activities of gold particles deposited onto an electrode unmodified and modified with a self-organized monolayer of cystamine in oxidation of dopamine and uric acid were compared. The possibility of joint determination of dopamine and uric acid on an electrode modified with self-organized monolayer of cystamine with gold nanoparticles was examined. © 2011 Pleiades Publishing, Ltd