Deconvolution problems in x-ray absorption fine structure

A Bayesian method application to the deconvolution of EXAFS spectra is considered. It is shown that for purposes of EXAFS spectroscopy, from the infinitely large number of Bayesian solutions it is possible to determine an optimal range of solutions, any one from which is appropriate. Since this removes the requirement for the uniqueness of solution, it becomes possible to exclude the instrumental broadening and the lifetime broadening from EXAFS spectra. In addition, we propose several approaches to the determination of optimal Bayesian regularization parameter. The Bayesian deconvolution is compared with the deconvolution which uses the Fourier transform and optimal Wiener filtering. It is shown that XPS spectra could be in principle used for extraction of a one-electron absorptance. The amplitude correction factors obtained after deconvolution are considered and discussed.Comment: 6 two-column pages, 5 eps figures; submitted to J. Phys.: Appl. Phy

XAFS spectroscopy. I. Extracting the fine structure from the absorption spectra

Three independent techniques are used to separate fine structure from the absorption spectra, the background function in which is approximated by (i) smoothing spline. We propose a new reliable criterion for determination of smoothing parameter and the method for raising of stability with respect to k_min variation; (ii) interpolation spline with the varied knots; (iii) the line obtained from bayesian smoothing. This methods considers various prior information and includes a natural way to determine the errors of XAFS extraction. Particular attention has been given to the estimation of uncertainties in XAFS data. Experimental noise is shown to be essentially smaller than the errors of the background approximation, and it is the latter that determines the variances of structural parameters in subsequent fitting.Comment: 16 pages, 7 figures, for freeware XAFS analysis program, see http://www.crosswinds.net/~klmn/viper.htm

EEG representing on brain surface using volume rendering

Brain research is challenging. One of the standard research methods is electroencephalography (EEG). As a rule, this study is presented in the form of graphs. This article describes an approach in which this data is mapped onto a brain model generated from a magnetic resonance imaging (MRI) scan. This allows you to look at the EEG study from a different point of view. An MRI scan will also allow you to take into account some of the features of the brain. This is an advantage over mapping just to a brain template. This non-invasive system can be implemented to monitor the patient in real-time, for example, during space flight

Acquisition, storage and dissemination of socially dangerous information : theoretical and methodological issues of the legal prohibition

The research project is focused on the Russian and foreign practice of the legal prohibition of acquisition, storage and dissemination of socially dangerous information on the Internet. Other objects of studies include legal restrictions on freedom of the media in order to protect the constitutional order, the interests of the citizens and the security of the state.peer-reviewe

Bonding trends within ternary Isocoordinate chalcogenide glasses GeAsSe

A structural study is presented of ab-initio molecular dynamics simulations of Ge-As-Se calcogenide glasses performed at the same mean coordination number but differing stoichiometry ranging between Se rich and Se poor glasses. Starting configurations are generated via Reverse Monte Carlo (RMC) simulations of Extended X-ray Absorption Fine Structure (EXAFS) measurements of experimental samples. Structural analysis is presented illustrating the bonding trends found with changing stoichiometry.Comment: 26 pages, 9 figures. Submitted to Physical Review