Planets of the solar system

Venera and Mariner spacecraft and ground based radio astronomy and spectroscopic observations of the atmosphere and surface of venus are examined. The composition and structural parameters of the atmosphere are discussed as the basis for development of models and theories of the vertical structure of the atmosphere, the greenhouse effect, atmospheric circulation and cloud cover. Recommendations for further meteorological studies are given. Ground based and Pioneer satellite observation data on Jupiter are explored as well as calculations and models of the cloud structure, atmospheric circulation and thermal emission field of Jupiter

Algorithm and program for information processing with the filin apparatus

The reduction of spectral radiation data from space sources is described. The algorithm and program for identifying segments of information obtained from the Film telescope-spectrometer on the Salyut-4 are presented. The information segments represent suspected X-ray sources. The proposed algorithm is an algorithm of the lowest level. Following evaluation, information free of uninformative segments is subject to further processing with algorithms of a higher level. The language used is FORTRAN 4

Josephson currents in point contacts between dirty two-band superconductors

We developed microscopic theory of Josephson effect in point contacts between dirty two-band superconductors. The general expression for the Josephson current, which is valid for arbitrary temperatures, is obtained. This expression was used for calculation of current-phase relations and temperature dependences of critical current with application to MgB2 superconductor. Also we have considered influence on contact characteristics interband scattering effect appeared in case of dirty superconductors. It is shown that the correction to Josephson current due to the interband scattering depends on phase shift in the banks (i.e. s- or s+/- -wave symmetry of order parameters)Comment: 11 pages, 3 figures Submitted to Low. Temp. Phy

Upper critical fields and thermally-activated transport of Nd(O_0.7F_0.3)FeAs single crystal

We present measurements of the resistivity and the upper critical field H_c2 of Nd(O_0.7F_0.3)FeAs single crystals in strong DC and pulsed magnetic fields up to 45 T and 60 T, respectively. We found that the field scale of H_c2 is comparable to ~100 T of high T_c cuprates. H_c2(T) parallel to the c-axis exhibits a pronounced upward curvature similar to what was extracted from earlier measurements on polycrystalline samples. Thus this behavior is indeed an intrinsic feature of oxypnictides, rather than manifestation of vortex lattice melting or granularity. The orientational dependence of H_c2 shows deviations from the one-band Ginzburg-Landau scaling. The mass anisotropy decreases as T decreases, from 9.2 at 44K to 5 at 34K. Spin dependent magnetoresistance and nonlinearities in the Hall coefficient suggest contribution to the conductivity from electron-electron interactions modified by disorder reminiscent that of diluted magnetic semiconductors. The Ohmic resistivity measured below T_c but above the irreversibility field exhibits a clear Arrhenius thermally activated behavior over 4-5 decades. The activation energy has very different field dependencies for H||ab and H\perp ab. We discuss to what extent different pairing scenarios can manifest themselves in the observed behavior of H_{c2}, using the two-band model of superconductivity. The results indicate the importance of paramagnetic effects on H_c2(T),which may significantly reduce H_c2(0) as compared toH_c2(0)~200-300 T based on extrapolations of H_c2(T) near T_c down to low temperatures.Comment: 11 pages, 16 figure

Superconducting gap and pair breaking in CeRu2 studied by point contacts

The superconducting gap in a CeRu$_{2}$ single crystal is investigated by point contacts. BCS-like behavior of the gap $\Delta$ in the temperature range below T$_{c}^{*}<$T$_{c}$, where T$_{c}$ is the critical temperature, is established, indicating the presence of a gapless superconductivity region (between T$_{c}^{*}$ and T$_{c}$). The pair-breaking effect of paramagnetic impurities, supposedly Ce ions, is taken into consideration using the Scalski-Betbeder-Matibet-Weiss approach based on Abrikosov-Gorkov theory. It allows us to recalculate the superconducting order parameter $\Delta ^{\alpha}$ (in the presence of paramagnetic impurities) and the gap $\Delta ^{P}$ (in the pure case) for the single crystal and for the previously studied polycrystalline CeRu$_{2}$. The value 2$\Delta^{P}$(0)$\approx$2 meV, with 2$\Delta ^{P}$(0)$/$k$_{B}$T$_{c} \approx$3.75, is found in both cases, indicating that CeRu$_{2}$ is a ``moderate'' strong-coupling superconductor.Comment: 4 pages incl. 3 figs., publ. in Fiz. Nizk. Temp. (http://fnte.ilt.kharkov.ua/list.html

Electromagnetic Pulse Driven Spin-dependent Currents in Semiconductor Quantum Rings

We investigate the non-equilibrium charge and spin-dependent currents in a quantum ring with a Rashba spin orbit interaction (SOI) driven by two asymmetric picosecond electromagnetic pulses. The equilibrium persistent charge and persistent spin-dependent currents are investigated as well. It is shown that the dynamical charge and the dynamical spin-dependent currents vary smoothly with a static external magnetic flux and the SOI provides a SU(2) effective flux that changes the phases of the dynamic charge and the dynamic spin-dependent currents. The period of the oscillation of the total charge current with the delay time between the pulses is larger in a quantum ring with a larger radius. The parameters of the pulse fields control to a certain extent the total charge and the total spin-dependent currents. The calculations are applicable to nano-meter rings fabricated in heterojuctions of III-V and II-VI semiconductors containing several hundreds electrons.Comment: 15pages, 5 figure

On the Ginzburg-Landau Analysis of the Upper Critical Field Hc2 in MgB2

Temperature dependence of the upper critical field Hc2 (T) for the superconducting magnesium diboride, MgB2, is studied in the vicinity of Tc by using a two-band Ginzburg-Landau (G-L) theory. The temperature dependence of Hc2 (T) near Tc exhibits a positive curvature. In addition, the calculated temperature dependence and its higher order derivatives are also shown to be in a good agreement with the experimental data. In analogy with the multi-band character of Eliashberg microscopic theory, the positive curvature of Hc2 (T) is described reasonably by solving the two-band of G-L theory.Comment: 14 pages, 2 figures, submitted to SUST November 200

The analysis of methylation of DNA promoter of SFRP2 gene in patients with hyperplastic processes of the endometrium

The hyperplastic processes of the endometrium can arise not only against the background of excessive influence of estrogen, but also against the background of epigenetic damages that affect apoptosis, cell proliferation, differentiation, and adhesion, and DNA reparation. The aim of our study was to investigate and analyze the status of methylation of the promoter of SFRP2 gene in patients with hyperplastic processes of the endometrium. Materials and Methods: The study groups were the following: I — patients with endometrial hyperplasia (EH, n = 9); II — patients with endometrial intraepithelial neoplasia (EIN, n = 10), III — control groups: 1) with endometrial cancer (EC, n = 4), and 2) healthy women (n = 4). Determination of promoter methylation of SFRP2 gene was carried out by the semiquantitative method of methylation-specific PCR assay. Results: The maximum level of methylation of SFRP2 gene promoter had been revealed in patients with EC — 42.80 ± 3.55% (р < 0.05). The patients of the I group had the lowest values of methylation of SFRP2 gene promoter — 10.66 ± 0.85%, while in patients of the II group this indicator was higher — 20.60 ± 0.95% (р < 0.05). In healthy women of the control group, methylation of SFRP2 gene promoter was detected in none of the samples. Conclusion: The content of the methylated SFRP2 gene in endometrial tissue of patients with hyperplastic processes higher than 20–25% allows relate these women to the risk group of EC development and dictates the need of intensive observation of such patients

Constraining Sources of Ultra High Energy Cosmic Rays Using High Energy Observations with the Fermi Satellite

We analyze the conditions that enable acceleration of particles to ultra-high energies, ~10^{20} eV (UHECRs). We show that broad band photon data recently provided by WMAP, ISOCAM, Swift and Fermi satellites, yield constraints on the ability of active galactic nuclei (AGN) to produce UHECRs. The high energy (MeV - GeV) photons are produced by Compton scattering of the emitted low energy photons and the cosmic microwave background or extra-galactic background light. The ratio of the luminosities at high and low photon energies can therefore be used as a probe of the physical conditions in the acceleration site. We find that existing data excludes core regions of nearby radio-loud AGN as possible acceleration sites of UHECR protons. However, we show that giant radio lobes are not excluded. We apply our method to Cen A, and show that acceleration of protons to ~10^{20} eV can only occur at distances >~ 100 kpc from the core.Comment: Extended discussion on former results; Accepted for publication in JCA

Dark matter and sub-GeV hidden U(1) in GMSB models

Motivated by the recent PAMELA and ATIC data, one is led to a scenario with heavy vector-like dark matter in association with a hidden $U(1)_X$ sector below GeV scale. Realizing this idea in the context of gauge mediated supersymmetry breaking (GMSB), a heavy scalar component charged under $U(1)_X$ is found to be a good dark matter candidate which can be searched for direct scattering mediated by the Higgs boson and/or by the hidden gauge boson. The latter turns out to put a stringent bound on the kinetic mixing parameter between $U(1)_X$ and $U(1)_Y$: $\theta \lesssim 10^{-6}$. For the typical range of model parameters, we find that the decay rates of the ordinary lightest neutralino into hidden gauge boson/gaugino and photon/gravitino are comparable, and the former decay mode leaves displaced vertices of lepton pairs and missing energy with distinctive length scale larger than 20 cm for invariant lepton pair mass below 0.5 GeV. An unsatisfactory aspect of our model is that the Sommerfeld effect cannot raise the galactic dark matter annihilation by more than 60 times for the dark matter mass below TeV.Comment: 1+15 pages, 4 figures, version published in JCAP, references added, minor change