81 research outputs found

    Magnetic field and plasma inside and outside of the Martian magnetosphere

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    Simultaneous magnetic and plasma measurements, carried out by wide angle plasma detectors in the Mars environment, are compared in order to identify regions with significantly different physical properties. Magnetograms and ion spectra indicate changes in the magnetopause and magnetosphere of Mars that are associated with the dynamic pressure effect of the solar wind

    High-frequency oscillations in low-dimensional conductors and semiconductor superlattices induced by current in stack direction

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    A narrow energy band of the electronic spectrum in some direction in low-dimensional crystals may lead to a negative differential conductance and N-shaped I-V curve that results in an instability of the uniform stationary state. A well-known stable solution for such a system is a state with electric field domain. We have found a uniform stable solution in the region of negative differential conductance. This solution describes uniform high-frequency voltage oscillations. Frequency of the oscillation is determined by antenna properties of the system. The results are applicable also to semiconductor superlattices.Comment: 8 pages, 3 figure

    On Effect of Equilibrium Fluctuations on Superfluid Density in Layered Superconductors

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    We calculate suppression of inter- and intralayer superconducting currents due to equilibrium phase fluctuations and find that, in contrast to a recent prediction, the effect of thermal fluctuations cannot account for linear temperature dependence of the superfluid density in high-Tc superconductors at low temperatures. Quantum fluctuations are found to dominate over thermal fluctuations at low temperatures due to hardening of their spectrum caused by the Josephson plasma resonance. Near Tc sizeable thermal fluctuations are found to suppress the critical current in the stack direction stronger, than in the direction along the layers. Fluctuations of quasiparticle branch imbalance make the spectral density of voltage fluctuations at small frequencies non zero, in contrast to what may be expected from a naive interpretation of Nyquist formula.Comment: 5 pages, LaTeX, RevTeX, Submitted to PR

    ORGANIZATIONAL ASPECTS OF ORGAN DONATION IN ST. PETERSBURG

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    COSTOYaNIE SISTEMY OSTEOPROTEGERIN (OPG) - LIGAND RETsEPTORA-AKTIVATORA YaDERNOGO FAKTORA KAPPA-V (RANKL)u patsientov s diabeticheskoy osteoartropatiey i mediakal'tsinozom arteriy nizhnikh konechnostey

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    That were 107 patients included. 33 patients with acute stage of diabetic osteoarthropathy, 24 patients with chronic stage; 20 patients with severe diabetic neuropathy and medial arterial calcification (MAC) of the low extremity, confirmed X-rays; control group included 30 persons with normal glucose tolerance. Significant increased level of OPG revealed in all groups of patients with diabetes (
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