11 research outputs found

    Primordial Nucleosynthesis for the New Cosmology: Determining Uncertainties and Examining Concordance

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    Big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) have a long history together in the standard cosmology. The general concordance between the predicted and observed light element abundances provides a direct probe of the universal baryon density. Recent CMB anisotropy measurements, particularly the observations performed by the WMAP satellite, examine this concordance by independently measuring the cosmic baryon density. Key to this test of concordance is a quantitative understanding of the uncertainties in the BBN light element abundance predictions. These uncertainties are dominated by systematic errors in nuclear cross sections. We critically analyze the cross section data, producing representations that describe this data and its uncertainties, taking into account the correlations among data, and explicitly treating the systematic errors between data sets. Using these updated nuclear inputs, we compute the new BBN abundance predictions, and quantitatively examine their concordance with observations. Depending on what deuterium observations are adopted, one gets the following constraints on the baryon density: OmegaBh^2=0.0229\pm0.0013 or OmegaBh^2 = 0.0216^{+0.0020}_{-0.0021} at 68% confidence, fixing N_{\nu,eff}=3.0. Concerns over systematics in helium and lithium observations limit the confidence constraints based on this data provide. With new nuclear cross section data, light element abundance observations and the ever increasing resolution of the CMB anisotropy, tighter constraints can be placed on nuclear and particle astrophysics. ABRIDGEDComment: 54 pages, 20 figures, 5 tables v2: reflects PRD version minor changes to text and reference

    Pb, Cd, Se, As in blood and urine of children from high and low polluted districts of Saint-Petersburg. The elements concentrations and health of children

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    At present time rapt attention is attended on child health. One of the main factors of child health is environmental condition and possibility of toxic elements consuniption by children from air, water, and food. The ain of our investigation is to detennine Pb, Cd, Se, As in blood and urine of children from high and low level polluted districts of St.-Petersburg. And then to estimate urine and blood toxic elements concentration correlation. ln order to examine large child groups it is necessary to use effective, express analycal methods. Wc chose Zeeman Modulation Polarization Atomic Absorption Spectrometry with High-Frequency Modulation as such a method. New technique Zeeman Modulation Polarization Atomic Absorption Spectrometry with High-Frequency Modulation allow io determine many etements directly (without additional compounds and reagents or with there minimum use) in blood, plasma and urine. Highcst spectrometry selectivity allows working with high background level. The matrix effects are reduced in great deal the aid of L'vov platform, sample pyrolysis and palladium modifier using. We present the results of our investigation – the concentration of toxic éléments in blood and urine of children from high–Polluted district is above permitted level

    Mass Spectrometry in Russia

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    Third-Order Nonlinear Optical Response of Metal Nanoparticles

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    Lasers

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    Nonlinear Interactions of Light and Matter Without Absorption

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