626 research outputs found

    Establishment of the spectra of kinetic turbulence

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    An analysis of kinetic equations describing the establishment of Langmuir turbulence spectra is presented. Secondary turbulence occurs where stationary distribution consists of many peaks. The position of peaks is established and their amplitudes complete undamped oscillations. It is pointed out that establishing spectra can occur only during adiabatic inclusion of pumping. It is significant here that the adiabiatic condition is more rigid than the ordinary by several hundred times

    Cost of human capital estimation and management in medical organization

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    © Medwell Journals, 2016.The purpose of this research is the analysis and improvement of technology of human capital cost management for maintaining efficient personnel policy in a modern organization. The study offers researchers method of assessment and management of investments in human capital. This method involves structure of cost behavior during formation and development of human capital, change history of investment risks on each stage of business career, modeling of volume of investments on various degrees of their riskiness, mathematical analysis and forecasting profitability of investments in human capital, development of recommendations on human capital cost management. Furthermore, it determines investment appeal of human capital development. The real method is assayed on the materials of a project on human capital development in "KORL" JSC. To maintain human capital cost management we offer systematic monitoring of its current value and change on the basis of the offered optimizing models, following the investment approach for personnel decision making, personalization in accounting the investments in human capital and its profitability

    УСТРАНЕНИЕ МАТРИЧНЫХ НЕСПЕКТРАЛЬНЫХ ПОМЕХ ПРИ ЭЛЕМЕНТНОМ АНАЛИЗЕ БИОЛОГИЧЕСКИХ ЖИДКОСТЕЙ НА КВАДРУПОЛЬНОМ МАСС-СПЕКТРОМЕТРЕ С ИНДУКТИВНО СВЯЗАННОЙ ПЛАЗМОЙ

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    The comparison of two most frequently used sample preparation techniques of biological fluids before mass-spectrometric determination of Mn, Co, Cu, Zn, As, Se, Cd and Pb – simple (direct) dilution and acid mineralization – was carried out using quadrupole mass-spectrometer. The significant underestimation of the results in comparison with diluted samples for the elements with relatively high ionization potentials was found while analyzing digested biofluids. The key role of acid effect was proven to be the reason of such discrepancy. Moreover, the contributions of saline and organic matrix non-spectral interferences in both diluted and mineralized samples – to the underestimation of the obtained results were evaluated. It was shown that the selection of the appropriate internal standard based on matching of the standard’s and analyte’s ionization potentials not the masses can eliminate the described interferences without matrix-matched calibration. Furthermore, the working mass-spectrometer conditions that allow to use any single internal standard (irrespective of it’s mass and/or ionization potential) were found. Based on the experimental data the approach of element determination in biological fluids with the use of quadrupole ICP-MS was suggested. It provides the possibility of simultaneous determination of various elements without changing the work mass-spectrometer conditions. The satisfactory agreement between the found and certified concentration values for all the elements analyzed in the diluted and mineralized samples of whole blood and urine reference materials proved the applicability of the approach.Keywords: biological fluids, elemental analysis, inductively coupled mass-spectrometry, matrix non-spectral interferences, internal standards(Russian)DOI: http://dx.doi.org/10.15826/analitika.2014.18.2.003 K.B. Osipov1, I. F. Seregina1, M. A. Bol`shov1,2 1Lomonosov Moscow State University, Moscow, Russian Federation2Institute for Spectroscopy RAS, Troitsk, Moscow, Russian FederationНа примере определения Mn, Co, Cu, Zn, As, Se, Cd и Pb в цельной крови и моче с использованием квадрупольного масс-спектрометра с индуктивно связанной плазмой Agilent 7500c произведено сравнение двух наиболее часто применяемых способов пробоподготовки биологических жидкостей: прямого разбавления и кислотного разложения. Обнаружено значительное занижение результатов анализа в минерализованных пробах (по сравнению с результатами анализа в разбавленных образцах) для элементов с относительно высоким первым потенциалом ионизации. Показано, что основной причиной такого расхождения является различие проб и градуировочных растворов по матричному составу: высокая кислотность проб после разложения. Дополнительно оценены вклады солевого и органического состава матрицы в занижение получаемых результатов как в разложенных, так и разбавленных пробах. Установлено, что для устранения подобных помех при использовании масс-спектрометра данной комплектации без подбора матрицы градуировочных растворов ключевым является выбор элемента внутреннего стандарта, который осуществляется, исходя из близости его первого потенциала ионизации к соответствующему потенциалу ионизации определяемого элемента. Найден режим работы прибора, который позволяет использовать один любой внутренний стандарт независимо от его природы – атомной массы и/или потенциала ионизации. На основании проведенных исследований предложена схема анализа указанных образцов с использованием квадрупольного масс-спектрометра с индуктивно связанной плазмой, обеспечивающая одновременное определение различных элементов без оптимизации рабочих параметров для каждого аналита. Удовлетворительное совпадение между найденными и аттестованными значениями концентраций всех элементов, определяемых в разбавленных и разложенных образцах сравнения цельной крови и мочи, подтверждает применимость подхода.Ключевые слова: биологические жидкости, элементный анализ, масс-спектрометрия с индуктивно связанной плазмой, матричные неспектральные помехи, внутренний стандарт.DOI: http://dx.doi.org/10.15826/analitika.2014.18.2.003

    Possibilities and Limitations of ICP-Spectrometric Determination of the Total Content of Tin, Its Inorganic and Organic Speciations in Waters with Different Salinity Levels—Part 1: Determination of the Total Tin Content

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    This paper considers the features of determining the total tin content in waters with different salinity. Direct ICP-spectrometric analysis of sea waters with a salinity of more than 6‰ significantly reduced the analytical signal of tin by 70% (ICP-MS) and 30% (ICP-OES). The matrix effect of macrocomponents was eliminated by generating hydrides using 0.50 M sodium borohydride and 0.10 M hydrochloric acid. The effect of transition metals on the formation of tin hydrides was eliminated by applying L-cysteine at a concentration of 0.75 g/L. The total analyte concentrations, considering the content of organotin compounds, were determined after microwave digestion of sample with oxidizing mixtures based on nitric acid. The generation of hydrides with the ICP-spectrometric determination of tin leveled the influence of the sea water matrix and reduced its detection limit from 0.50 up to 0.05 µg/L for all digestion schemes. The developed analysis scheme made it possible to determine the total content of inorganic and organic forms of tin in sea waters. The total content of tin was determined in the waters of the Azov and Black seas at the levels of 0.17 and 0.24 µg/L, respectively. © 2023 by the authors.Ministry of Education and Science of the Russian Federation, Minobrnauka: FZEN-2023-0006This work was supported by the Ministry of Education and Science of the Russian Federation FZEN-2023-0006

    Stochastic Pulse Switching in a Degenerate Resonant Optical Medium

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    Using the idealized integrable Maxwell-Bloch model, we describe random optical-pulse polarization switching along an active optical medium in the Lambda-configuration with disordered occupation numbers of its lower energy sub-level pair. The description combines complete integrability and stochastic dynamics. For the single-soliton pulse, we derive the statistics of the electric-field polarization ellipse at a given point along the medium in closed form. If the average initial population difference of the two lower sub-levels vanishes, we show that the pulse polarization will switch intermittently between the two circular polarizations as it travels along the medium. If this difference does not vanish, the pulse will eventually forever remain in the circular polarization determined by which sub-level is more occupied on average. We also derive the exact expressions for the statistics of the polarization-switching dynamics, such as the probability distribution of the distance between two consecutive switches and the percentage of the distance along the medium the pulse spends in the elliptical polarization of a given orientation in the case of vanishing average initial population difference. We find that the latter distribution is given in terms of the well-known arcsine law

    Inclusive Search for Anomalous Production of High-pT Like-Sign Lepton Pairs in Proton-Antiproton Collisions at sqrt{s}=1.8 TeV

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    We report on a search for anomalous production of events with at least two charged, isolated, like-sign leptons with pT > 11 GeV/c using a 107 pb^-1 sample of 1.8 TeV ppbar collisions collected by the CDF detector. We define a signal region containing low background from Standard Model processes. To avoid bias, we fix the final cuts before examining the event yield in the signal region using control regions to test the Monte Carlo predictions. We observe no events in the signal region, consistent with an expectation of 0.63^(+0.84)_(-0.07) events. We present 95% confidence level limits on new physics processes in both a signature-based context as well as within a representative minimal supergravity (tanbeta = 3) model.Comment: 15 pages, 4 figures. Minor textual changes, cosmetic improvements to figures and updated and expanded reference

    Measurement of WγW\gamma and ZγZ\gamma Production in ppˉp\bar{p} Collisions at s\sqrt{s} = 1.96 TeV

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    The Standard Model predictions for WγW\gamma and ZγZ\gamma production are tested using an integrated luminosity of 200 pb1^{-1} of \ppbar collision data collected at the Collider Detector at Fermilab. The cross sections are measured selecting leptonic decays of the WW and ZZ bosons, and photons with transverse energy ET>7E_T>7 GeV that are well separated from leptons. The production cross sections and kinematic distributions for the WγW\gamma and ZγZ\gamma are compared to SM predictions.Comment: 7 pages, 4 figures, submitted to PR

    Evidence for the exclusive decay Bc+- to J/psi pi+- and measurement of the mass of the Bc meson

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    We report first evidence for a fully reconstructed decay mode of the B_c^{\pm} meson in the channel B_c^{\pm} \to J/psi \pi^{\pm}, with J/psi \to mu^+mu^-. The analysis is based on an integrated luminosity of 360 pb$^{-1} in p\bar{p} collisions at 1.96 TeV center of mass energy collected by the Collider Detector at Fermilab. We observe 14.6 \pm 4.6 signal events with a background of 7.1 \pm 0.9 events, and a fit to the J/psi pi^{\pm} mass spectrum yields a B_c^{\pm} mass of 6285.7 \pm 5.3(stat) \pm 1.2(syst) MeV/c^2. The probability of a peak of this magnitude occurring by random fluctuation in the search region is estimated as 0.012%.Comment: 7 pages, 3 figures. Version 3, accepted by PR

    Measurement of the Lifetime Difference Between B_s Mass Eigenstates

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    We present measurements of the lifetimes and polarization amplitudes for B_s --> J/psi phi and B_d --> J/psi K*0 decays. Lifetimes of the heavy (H) and light (L) mass eigenstates in the B_s system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203 +/- 15 B_s decays, we obtain tau_L = (1.05 +{0.16}/-{0.13} +/- 0.02) ps and tau_H = (2.07 +{0.58}/-{0.46} +/- 0.03) ps. Expressed in terms of the difference DeltaGamma_s and average Gamma_s, of the decay rates of the two eigenstates, the results are DeltaGamma_s/Gamma_s = (65 +{25}/-{33} +/- 1)%, and DeltaGamma_s = (0.47 +{0.19}/-{0.24} +/- 0.01) inverse ps.Comment: 8 pages, 3 figures, 2 tables; as published in Physical Review Letters on 16 March 2005; revisions are for length and typesetting only, no changes in results or conclusion

    Top quark mass measurement using the template method at CDF

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    We present a measurement of the top quark mass in the lepton+jets and dilepton channels of ttˉt\bar{t} decays using the template method. The data sample corresponds to an integrated luminosity of 5.6 fb1^{-1} of ppˉp\bar{p} collisions at Tevatron with s=1.96\sqrt{s}=1.96 TeV, collected with the CDF II detector. The measurement is performed by constructing templates of three kinematic variables in the lepton+jets and two kinematic variables in the dilepton channel. The variables are two reconstructed top quark masses from different jets-to-quarks combinations and the invariant mass of two jets from the WW decay in the lepton+jets channel, and a reconstructed top quark mass and mT2m_{T2}, a variable related to the transverse mass in events with two missing particles, in the dilepton channel. The simultaneous fit of the templates from signal and background events in the lepton+jets and dilepton channels to the data yields a measured top quark mass of Mtop=172.1±1.1(stat)±0.9(syst).M_{top} = 172.1 \pm 1.1(stat) \pm 0.9(syst).Comment: submitted to Phys. Rev.
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