915 research outputs found

    Statistics of a noise-driven Manakov soliton

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    We investigate the statistics of a vector Manakov soliton in the presence of additive Gaussian white noise. The adiabatic perturbation theory for Manakov soliton yields a stochastic Langevin system which we analyze via the corresponding Fokker-Planck equation for the probability density function (PDF) for the soliton parameters. We obtain marginal PDFs for the soliton frequency and amplitude as well as soliton amplitude and polarization angle. We also derive formulae for the variances of all soliton parameters and analyze their dependence on the initial values of polarization angle and phase.Comment: Submitted to J.Phys.A: Mathematical and Genera

    Characterization of carbon contamination under ion and hot atom bombardment in a tin-plasma extreme ultraviolet light source

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    Molecular contamination of a grazing incidence collector for extreme ultraviolet (EUV) lithography was experimentally studied. A carbon film was found to have grown under irradiation from a pulsed tin plasma discharge. Our studies show that the film is chemically inert and has characteristics that are typical for a hydrogenated amorphous carbon film. It was experimentally observed that the film consists of carbon (~70 at. %), oxygen (~20 at. %) and hydrogen (bound to oxygen and carbon), along with a few at. % of tin. Most of the oxygen and hydrogen are most likely present as OH groups, chemically bound to carbon, indicating an important role for adsorbed water during the film formation process. It was observed that the film is predominantly sp3 hybridized carbon, as is typical for diamond-like carbon. The Raman spectra of the film, under 514 and 264 nm excitation, are typical for hydrogenated diamond-like carbon. Additionally, the lower etch rate and higher energy threshold in chemical ion sputtering in H2 plasma, compared to magnetron-sputtered carbon films, suggests that the film exhibits diamond-like carbon properties.Comment: 18 pages, 10 figure

    Interannual variability of the Black Sea Proper oxygen and nutrients regime: The role of climatic and anthropogenic forcing

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    The Black Sea is a unique, stratified, enclosed ocean basin of great importance. The water column provides a wealth of information concerning aerobic-anaerobic biogeochemistry, the responses of which can have links to anthropogenic and climatic forcing. Herein, we synthesize dissolved oxygen (DO) and nutrient data (phosphate, dissolved inorganic nitrogen (DIN), and silicate) for the period 1984-2010 received in the northeastern and western areas of the Sea. In the subsequent analysis we discuss the role of anthropogenic and climatic forcing in the context of the Black Sea oxic layer and oxic/anoxic interface characteristics.The DO concentration in the surface layer and in the Cold Intermediate Layer (CIL) decreased in warm periods and increased in cold periods, correlating to North Atlantic Oscillation (NAO) index variation. The biogeochemical regime of the Black Sea oxygenated upper layer has notably changed since 1999. After 1999 DO concentration in the CIL decreased by 20% while the concentrations in the surface layer changed very little. This provides evidence that the CIL waters were not fully replenished during the winters of the last decade.The nutrient concentrations (DIN and phosphate) in the surface layer decreased significantly in the 2000s compared with the 1980s-1990s. This decrease is regarded as improvement of the Black Sea ecosystem state. Oxygen and nutrient dynamics in the middle pycnocline have been decoupled since 1999. Presently physical (climatic) forcing is the dominant affecting factor controlling the Sea oxygen and nitrogen regime. © 2013 Elsevier Ltd

    College of Arts and Sciences at Governors State University Announces Winter 2008 Dean’s List

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    The College of Arts and Sciences at Governors State University recently recognized undergraduate students who earned a 3.7 grade point average or higher during the Winter 2008 trimester

    Correction of retinal ischemia/reperfusion by 3-(1H-benzimidazol-2-il)-1,2,2-trimethyl cyclopentancarbonic acid in experiment

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    Results of ocular fundus studies revealed the most pronounced protective effects of 3-(1Hbenzimidazol-2-il)-1,2,2-trimethyl cyclopentancarbonic acid in a dose 50 mg/kg on the model of retinal ischemiareperfusion in Wistar rats, which is reflected in the restoration of the optic disc. Correction of retinal ischemiareperfusion by 3-(1H-benzimidazol-2-il)-1,2,2-trimethyl cyclopentancarbonic acid in a dose 50 mg/kg leads to higher values of the coefficient b/a of electroretinography after 72 hours of reperfusion compared to the group with pathology correction by the same drug in a dose 10 mg/kg, which indicates the restoration of the electrophysiological state of the retin

    Use of L-arginine immobilised on activated carbon for pharmacological correction of endothelial disfunction

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    For the first time a complex of L-arginine sodium salt of sulfate of cellulose acetate on activated carbon. To investigate the processes of sorption-desorption of L-arginine in a model environmen

    The Plateau de Bure Neutron Monitor: design, operation and Monte-Carlo simulation

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    This paper describes the Plateau de Bure Neutron Monitor (PdBNM), an instrument providing continuous ground-level measurements of atmospheric secondary neutron flux resulting from the interaction of primary cosmic rays with the Earth's atmosphere. The detector is installed on the Plateau de Bure (Devoluy mountains, south of France, latitude North 44{\deg} 38' 02", longitude East 5{\deg} 54' 26", altitude 2555 m) as a part of the ASTEP Platform (Altitude Single-event effects Test European Platform), a permanent installation dedicated to the study of the impact of terrestrial natural radiation on microelectronics circuit reliability. The present paper reports the neutron monitor design, its operation since August 2008 and its complete numerical simulation using the Monte Carlo codes GEANT4 and MCNPX. We particularly detail the computation of the neutron monitor detection response function for neutrons, muons, protons and pions, the comparison between GEANT4 and MCNPX numerical results and the evaluation of the PdBNM counting rate a function of both the nature and flux of the incident atmospheric particles.Comment: 37 pages, 14 figures, 5 tables; numerical error in GEANT4 particle sourse corrected, section 4.4 was significantly revised. Submitted to IEEE Transactions on Nuclear Scienc
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