Micrometeoric investigations in the near earth space according to observations on AES '' Kosmos-163''

Micrometeor observations in near earth space by Cosmos 16

Circular-Polarization-Dependent Study of Microwave-Induced Conductivity Oscillations in a Two-Dimensional Electron Gas on Liquid Helium

The polarization dependence of photoconductivity response at cyclotron-resonance harmonics in a nondegenerate two-dimensional (2D) electron system formed on the surface of liquid helium is studied using a setup in which a circular polarization of opposite directions can be produced. Contrary to the results of similar investigations reported for semiconductor 2D electron systems, for electrons on liquid helium, a strong dependence of the amplitude of magnetoconductivity oscillations on the direction of circular polarization is observed. This observation is in accordance with theoretical models based on photon-assisted scattering and, therefore, it solves a critical issue in the dispute over the origin of microwave-induced conductivity oscillations.Comment: 5 pages, 4 figure

Experimental data as evidence against the hypothesis on the earth's dust cloud

Cosmos and Explorer satellite data used to reject hypothesis of terrestrial meteoroid and dust cloud

Photon-induced vanishing of magnetoconductance in 2D electrons on liquid He

We report on a novel transport phenomenon realized by optical pumping in surface state electrons on helium subjected to perpendicular magnetic fields. The electron dynamics is governed by the photon-induced excitation and scattering-mediated transitions between electric subbands. In a range of magnetic fields, we observe vanishing longitudinal conductivity sigma_xx. Our result suggests the existence of radiation-induced zero-resistance states in the nondegenerate 2D electron system.Comment: 4 pages, 5 figure

Isochoric thermal conductivity of solid nitrogen

The isochoric thermal conductivity of solid nitrogen has been investigated on four samples of different densities in the temperature interval from 20 K to the onset of melting. In alfa-N2 the isochoric thermal conductivity exhibits a dependence weaker than 1/T; in beta-N2 it increases slightly with temperature. The experimental results are discussed within a model in which the heat is transported by low-frequency phonons or by "diffusive" modes above the mobility boundary. The growth of the thermal conductivity in beta-N2 is attributed to the decreasing "rotational" component of the total thermal resistance, which occurs as the rotational correlations between the neighboring molecules become weaker.Comment: Postscript 12 pages, 3 figures, 1 table. To be published in 200

Soft-Pulse Dynamical Decoupling with Markovian Decoherence

We consider the effect of broadband decoherence on the performance of refocusing sequences, having in mind applications of dynamical decoupling in concatenation with quantum error correcting codes as the first stage of coherence protection. Specifically, we construct cumulant expansions of effective decoherence operators for a qubit driven by a pulse of a generic symmetric shape, and for several sequences of $\pi$- and $\pi/2$-pulses. While, in general, the performance of soft pulses in decoupling sequences in the presence of Markovian decoherence is worse than that of the ideal $\delta$-pulses, it can be substantially improved by shaping.Comment: New version contains minor content clarification

On the Analysis of Chemical Composition of Moon's Surface by Direct Methods

Proportional counter for X ray emission detection and chemical analysis of lunar surface element

The clinical significance of urinary tract infection and Asymptomatic Bacteriuria in Type 2 Diabetes Mellitus patients in the general practices of Varna region - Bulgaria

Background: The urinary system of diabetics is one of their most frequently affected body systems. Periodic urine analysis reveals that asymptomatic bacteriuria is very often detected in this population. Objectives: The aim of the study is to estimate the clinical significance of upper urinary tract infection (UUT/) and asymptomatic bacteriuria (ABU) in diabetics in a general practice setting, their clinical characteristics, incidence, course, evolution and complications. Methods: We tested 560 patients with type 2 diabetes mellitus (DM) from 12 general practices ofVarna region, Bulgaria in a prospective study. We traced ABU in the group for 2 years. There were 310 female patients (55.4%) mean age 52.5 ± 3.2 years and duration of DM was 8.5 ± 2.8 years. Results: The results showed that in 11.14% ABU was significant. Only 4.82% of diabetics developed upper urinary tract infection and the complications from it were very rare: 0.89% pyonephrosis and 0.89% sepsis. Conclusions: Our conclusion was that upper urinary tract infection in diabetics was not as severe as reported in the literature. Pyelonephritis had a benign course and only 16.6% of our patients developed chronic renal failure a few years later but the reason for its development was not diabetic nephropathy. All these facts show that ABU disappears spontaneously in most diabetics. Relevance to general practice: We discuss the question: is it necessary for every case of ABU in diabetics in general practice to be treated and isn't it time to revaluate the postulated antibiotic treatment for diabetics with ABU?peer-reviewe