WorldWideScience

Sample records for alpha spectra

  1. The 1997 IAEA test spectra for alpha-particle spectrometry

    CERN Document Server

    Garcia-Torano, E; Woods, S; Blaauw, M; Fazinic, S

    1999-01-01

    In the framework of an IAEA intercomparison of software for alpha-particle spectrometry, a set of test spectra with reference files was produced for validation and comparison of alpha spectrum analysis programs. The considerations, the spectra and the methods employed to obtain them are presented.

  2. Infrared spectra of olivine polymorphs - Alpha, beta phase and spinel

    Science.gov (United States)

    Jeanloz, R.

    1980-01-01

    The infrared absorption spectra of several olivines (alpha phase) and their corresponding beta phase (modified spinel) and spinel (gamma) high-pressure polymorphs are determined. Spectra were measured for ground and pressed samples of alpha and gamma A2SiO4, where A = Fe, Ni, Co; alpha and gamma Mg2GeO4; alpha Mg2SiO4; and beta Co2SiO4. The spectra are interpreted in terms of internal, tetrahedral and octagonal, and lattice vibration modes, and the spinel results are used to predict the spectrum of gamma Mg2SiO4. Analysis of spectra obtained from samples of gamma Mg2GeO4 heated to 730 and 1000 C provides evidence that partial inversion could occur in silicate spinels at elevated temperatures and pressures.

  3. A method for the analysis of alpha spectra

    International Nuclear Information System (INIS)

    This work describes a method for the analysis of alpha septra collected with implanted ion detectors. It is an alternative methodology based in the use of a simple exponential mathematical function that allows modeling the tail of the alpha peaks in a wide range of channels into the low energy zone. The parameters of the function are analyzed, and the way to apply them is explained. In addition, some graphics of alpha spectra and the exponential curves is shown. Also, tables with results of the evaluation of the alpha peaks areas compared with their actual areas are presented. (author)

  4. A improved method for the analysis of alpha spectra

    International Nuclear Information System (INIS)

    In this work we describe a methodology, developed in the last years, for the analysis of alpha emitters spectra, obtained with implanted ion detectors, that tend to solve some of the problems that shows this type of spectra. This is an improved methodology respect to that described in a previous publication. The method is based on the application of a mathematical function that allows to model the tail of an alpha peak, to evaluate the part of the peak that is not seen in the cases of partial superposition with another peak. Also, a calculation program that works in a semiautomatic way, with the possibility of interactive intervention of the analyst, has been developed simultaneously and is described in detail. (author)

  5. The Lyman $\\alpha$ Forest in the Spectra of QSOs

    CERN Document Server

    Rauch, M

    1998-01-01

    Observations of redshifted Lyman alpha forest absorption in the spectra of quasistellar objects (QSOs) provide a highly sensitive probe of the distribution of gaseous matter in the universe. Over the past two decades optical spectroscopy with large ground-based telescopes, and more recently ultraviolet spectroscopy from space have yielded a wealth of information on what appears to be a gaseous, photoionized intergalactic medium, partly enriched by the products of stellar nucleosynthesis, residing in coherent structures over many hundreds of kiloparsecs. Recent progress with cosmological hydro-simulations based on hierarchical structure formation models has led to important insights into the physical structures giving rise to the forest. If these ideas are correct, a truely inter- and proto-galactic medium [at high redshift (z ~ 3), the main repository of baryons] collapses under the influence of dark matter gravity into flattened or filamentary structures, which are seen in absorption against background QSOs....

  6. Mean-flux Regulated PCA Continuum Fitting of SDSS Lyman-alpha Forest Spectra

    CERN Document Server

    Lee, Khee-Gan; Spergel, David N

    2011-01-01

    Continuum fitting is an important aspect of Lyman-alpha forest science, since errors in the estimated optical depths scale with the fractional continuum error. However, traditional methods of estimating continua in noisy and moderate-resolution spectra (S/N 5. The residual Fourier power in the continuum is decreased by a factor of a few in comparison with dividing by the mean continuum, enabling Lyman-alpha flux power spectrum measurements to be extended to ~2x larger scales. Using this new technique, we make available continuum fits for 12,069 z>2.3 Lyman-alpha forest spectra from SDSS DR7 for use by the community. This technique is also applicable to future releases of the ongoing BOSS survey, which is obtaining spectra for ~ 150,000 Lyman-alpha forest spectra at low signal-to-noise (S/N ~ 2).

  7. Improved composite spectra of quasars within the HI Ly\\alpha-forest region

    CERN Document Server

    Ivashchenko, G; Torbaniuk, O

    2011-01-01

    We present a new more accurate approach to the composite spectra construction based on stacking spectra with similar slopes \\alpha_\\lambda\\ within the wavelength range redward of Ly\\alpha\\ emission line, which allows to reduce a noise. With the help of this technique a detailed study of the HI Ly\\alpha-forest region (\\lambda_rest~1050-1200 \\AA) of the own sample of 3,439 medium-resolution quasar spectra from SDSS DR7 was performed. More than 14 lines were found within it, three of which were found in previous studies of quasar composite spectra from SDSS and some others were found in composite spectra from space-based telescopes or high-resolution spectra of individual quasars from ground-based telescopes. The parameters of these lines were calculated. It was shown that the continuum level within the Ly\\alpha-forest region cannot be considered as a power-low with the same slope as in the region redward of Ly\\alpha\\ emission line. Any dependence of the slope \\alpha_\\lambda\\ on luminosity in SDSS u, g, r and i ...

  8. Ly$\\alpha$ Spectra from Multiphase Outflows, and their Connection to Shell Models

    CERN Document Server

    Gronke, Max

    2016-01-01

    We perform Lyman-$\\alpha$ (Ly$\\alpha$) Monte-Carlo radiative transfer calculations on a suite of $2500$ models of multiphase, outflowing media, which are characterized by $14$ parameters. We focus on the Ly$\\alpha$ spectra emerging from these media, and investigate which properties are dominant in shaping the emerging Ly$\\alpha$ profile. Multiphase models give rise to a wide variety of emerging spectra, including single, double and triple peaked spectra. We find that the dominant parameters in shaping the spectra include (i) the cloud covering factor, $f_c$, in agreement with earlier studies, and (ii) the temperature and number density of residual HI in the hot ionized medium. We attempt to reproduce spectra emerging from multiphase models with `shell models' which are commonly used to fit observed Ly$\\alpha$ spectra, and investigate the connection between shell-model parameters and the physical parameters of the clumpy media. In shell models, the neutral hydrogen content of the shell is one of the key parame...

  9. Proton and alpha evaporation spectra in low energy 12C and 16O induced reactions

    Indian Academy of Sciences (India)

    E T Mirgle; D R Chakrabarty; V M Datar; Suresh Kumar; A Mitra; H H Oza

    2006-08-01

    Proton and alpha particle spectra have been measured in the 12C+93Nb and 12C+58Ni reactions at E(12C) = 40 and 50 MeV and in the 16O+93Nb reaction at E(16O) = 75 MeV. The spectra are compared with the statistical model calculations. The shapes of the calculated spectra are in agreement with experimental data except for the alpha spectrum in the 12C+93Nb reaction at 40 MeV. The observed evaporation bump is at ∼ 2 MeV lower energy compared to the calculated one. This discrepancy could imply alpha particle emission from a deformed configuration before compound nucleus formation at this near Coulomb barrier beam energy.

  10. ALFITeX: A code introducing improvements in the analysis of alpha spectra

    Energy Technology Data Exchange (ETDEWEB)

    Caro Marroyo, B.; Sanchez, A. Martin; Jurado Vargas, M. [Department of Physics, University of Extremadura, E-06006 Badajoz (Spain)

    2013-06-10

    A new code for the deconvolution of complex alpha-particle spectra, called ALFITeX, has been developed. The procedure is based on the Levenberg-Marquardt algorithm, with the curve fitting being the mathematical function formed by the convolution of a Gaussian with two left-handed exponential curves in the low-energy-tail region. ALFITeX has been checked with its application to the calculation of the alpha-particle emission probabilities of several nuclides.

  11. A new approach to the analysis of alpha spectra based on neural network techniques

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, A.; Miranda, J. [LARUEX, Environmental Radioactivity Laboratory, Dept. Applied Physics, Faculty of Veterinary Science, University of Extremadura, Avda. Universidad s/n, 10003 Caceres (Spain); Guillen, J., E-mail: fguillen@unex.es [LARUEX, Environmental Radioactivity Laboratory, Dept. Applied Physics, Faculty of Veterinary Science, University of Extremadura, Avda. Universidad s/n, 10003 Caceres (Spain); Corbacho, J.A. [LARUEX, Environmental Radioactivity Laboratory, Dept. Applied Physics, Faculty of Veterinary Science, University of Extremadura, Avda. Universidad s/n, 10003 Caceres (Spain); Perez, R. [Dept. Technology of Computers and Communications, Polytechnics School, University of Extremadura, Avda. Universidad s/n, 10003 Caceres (Spain)

    2011-10-01

    The analysis of alpha spectra requires good radiochemical procedures in order to obtain well differentiated alpha peaks in the spectrum, and the easiest way to analyze them is by directly summing the counts obtained in the Regions of Interest (ROIs). However, the low-energy tails of the alpha peaks frequently make this simple approach unworkable because some peaks partially overlap. Many fitting procedures have been proposed to solve this problem, most of them based on semi-empirical mathematical functions that emulate the shape of a theoretical alpha peak. The main drawback of these methods is that the great number of fitting parameters used means that their physical meaning is obscure or completely lacking. We propose another approach-the application of an artificial neural network. Instead of fitting the experimental data to a mathematical function, the fit is carried out by an artificial neural network (ANN) that has previously been trained to model the shape of an alpha peak using as training patterns several polonium spectra obtained from actual samples analyzed in our laboratory. In this sense, the ANN is able to learn the shape of an actual alpha peak. We have designed such an ANN as a feed-forward multi-layer perceptron with supervised training based on a back-propagation algorithm. The fitting procedure is based on the experimental observables that are characteristic of alpha peaks-the number of counts of the maximum and several peak widths at different heights. Polonium isotope spectra were selected because the alpha peaks corresponding to {sup 208}Po, {sup 209}Po, and {sup 210}Po are monoenergetic and well separated. The uncertainties introduced by this fitting procedure were less than the counting uncertainties. This new approach was applied to the problem of resolving overlapping peaks. Firstly, a theoretical study was carried out by artificially overlapping alpha peaks from actual samples in order to test the ability of the ANN to resolve each peak

  12. A new approach to the analysis of alpha spectra based on neural network techniques

    International Nuclear Information System (INIS)

    The analysis of alpha spectra requires good radiochemical procedures in order to obtain well differentiated alpha peaks in the spectrum, and the easiest way to analyze them is by directly summing the counts obtained in the Regions of Interest (ROIs). However, the low-energy tails of the alpha peaks frequently make this simple approach unworkable because some peaks partially overlap. Many fitting procedures have been proposed to solve this problem, most of them based on semi-empirical mathematical functions that emulate the shape of a theoretical alpha peak. The main drawback of these methods is that the great number of fitting parameters used means that their physical meaning is obscure or completely lacking. We propose another approach-the application of an artificial neural network. Instead of fitting the experimental data to a mathematical function, the fit is carried out by an artificial neural network (ANN) that has previously been trained to model the shape of an alpha peak using as training patterns several polonium spectra obtained from actual samples analyzed in our laboratory. In this sense, the ANN is able to learn the shape of an actual alpha peak. We have designed such an ANN as a feed-forward multi-layer perceptron with supervised training based on a back-propagation algorithm. The fitting procedure is based on the experimental observables that are characteristic of alpha peaks-the number of counts of the maximum and several peak widths at different heights. Polonium isotope spectra were selected because the alpha peaks corresponding to 208Po, 209Po, and 210Po are monoenergetic and well separated. The uncertainties introduced by this fitting procedure were less than the counting uncertainties. This new approach was applied to the problem of resolving overlapping peaks. Firstly, a theoretical study was carried out by artificially overlapping alpha peaks from actual samples in order to test the ability of the ANN to resolve each peak. Then, the ANN

  13. SOURCES 4C : a code for calculating ([alpha],n), spontaneous fission, and delayed neutron sources and spectra.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, W. B. (William B.); Perry, R. T. (Robert T.); Shores, E. F. (Erik F.); Charlton, W. S. (William S.); Parish, Theodore A.; Estes, G. P. (Guy P.); Brown, T. H. (Thomas H.); Arthur, Edward D. (Edward Dana),; Bozoian, Michael; England, T. R.; Madland, D. G.; Stewart, J. E. (James E.)

    2002-01-01

    SOURCES 4C is a computer code that determines neutron production rates and spectra from ({alpha},n) reactions, spontaneous fission, and delayed neutron emission due to radionuclide decay. The code is capable of calculating ({alpha},n) source rates and spectra in four types of problems: homogeneous media (i.e., an intimate mixture of a-emitting source material and low-Z target material), two-region interface problems (i.e., a slab of {alpha}-emitting source material in contact with a slab of low-Z target material), three-region interface problems (i.e., a thin slab of low-Z target material sandwiched between {alpha}-emitting source material and low-Z target material), and ({alpha},n) reactions induced by a monoenergetic beam of {alpha}-particles incident on a slab of target material. Spontaneous fission spectra are calculated with evaluated half-life, spontaneous fission branching, and Watt spectrum parameters for 44 actinides. The ({alpha},n) spectra are calculated using an assumed isotropic angular distribution in the center-of-mass system with a library of 107 nuclide decay {alpha}-particle spectra, 24 sets of measured and/or evaluated ({alpha},n) cross sections and product nuclide level branching fractions, and functional {alpha}-particle stopping cross sections for Z < 106. The delayed neutron spectra are taken from an evaluated library of 105 precursors. The code provides the magnitude and spectra, if desired, of the resultant neutron source in addition to an analysis of the'contributions by each nuclide in the problem. LASTCALL, a graphical user interface, is included in the code package.

  14. Numerical methods to analyze alpha spectra and application to the study of neptunium 237 and neptunium 236

    International Nuclear Information System (INIS)

    A set of numerical methods to analize alpha spectra measured with semiconductor detectors are presented. The methods can be divided in two groups, the first being based in the X2 minimization ands the second in the use of the Fourier Transform. The methods based in the minimization of X2 can, in turn, be divided according to the model used to fit the spectra. Some of them use a monoenergetic line for the intercomparison with the other peaks in the same spectrum. The others take into account the analytical function developed to represent an alpha line. Both allow the determination of positions and areas of the components, as well as the uncertainties of the results. The Fast Fourier Transform is applied to the second group of methods, which include the smoothing of experimental data, and the deconvolution of spectra. Examples are given of the application of these methods to real spectra. The alpha spectra of 237Np and 236Np are studied by using some of the methods described in this work. (Author)

  15. ELM: an Algorithm to Estimate the Alpha Abundance from Low-resolution Spectra

    Science.gov (United States)

    Bu, Yude; Zhao, Gang; Pan, Jingchang; Bharat Kumar, Yerra

    2016-01-01

    We have investigated a novel methodology using the extreme learning machine (ELM) algorithm to determine the α abundance of stars. Applying two methods based on the ELM algorithm—ELM+spectra and ELM+Lick indices—to the stellar spectra from the ELODIE database, we measured the α abundance with a precision better than 0.065 dex. By applying these two methods to the spectra with different signal-to-noise ratios (S/Ns) and different resolutions, we found that ELM+spectra is more robust against degraded resolution and ELM+Lick indices is more robust against variation in S/N. To further validate the performance of ELM, we applied ELM+spectra and ELM+Lick indices to SDSS spectra and estimated α abundances with a precision around 0.10 dex, which is comparable to the results given by the SEGUE Stellar Parameter Pipeline. We further applied ELM to the spectra of stars in Galactic globular clusters (M15, M13, M71) and open clusters (NGC 2420, M67, NGC 6791), and results show good agreement with previous studies (within 1σ). A comparison of the ELM with other widely used methods including support vector machine, Gaussian process regression, artificial neural networks, and linear least-squares regression shows that ELM is efficient with computational resources and more accurate than other methods.

  16. Radiative Transfer Modeling of Lyman Alpha Emitters. I. Statistics of Spectra and Luminosity

    OpenAIRE

    Zheng, Zheng; Cen, Renyue; Trac, Hy; Miralda-Escude, Jordi

    2009-01-01

    We combine a cosmological reionization simulation with box size of 100Mpc/h on a side and a Monte Carlo Lyman-alpha (Lya) radiative transfer code to model Lyman Alpha Emitters (LAEs) at z~5.7. The model introduces Lya radiative transfer as the single factor for transforming the intrinsic Lya emission properties into the observed ones. Spatial diffusion of Lya photons from radiative transfer results in extended Lya emission and only the central part with high surface brightness can be observed...

  17. Probing the Circumgalactic Medium at High-Redshift Using Composite BOSS Spectra of Strong Lyman-alpha Forest Absorbers

    CERN Document Server

    Pieri, Matthew M; Frank, Stephan; Crighton, Neil; Weinberg, David H; Lee, Khee-Gan; Noterdaeme, Pasquier; Bailey, Stephen J; Busca, Nicolas; Ge, Jian; Kirkby, David; Lundgren, Britt; Mathur, Smita; Paris, Isabelle; Palanque-Delabrouille, Nathalie; Petitjean, Patrick; Rich, James; Ross, Nicholas P; Schneider, Donald P; York, Donald G

    2013-01-01

    We present composite spectra constructed from a sample of 242,150 Lyman-alpha (Lya) forest absorbers at redshifts 2.4spectra from the Baryon Oscillation Spectroscopic Survey (BOSS) as part of Data Release 9 of the Sloan Digital Sky Survey III. We select forest absorbers by their flux in bins 138 km/s wide (approximately the size of the BOSS resolution element). We split these absorbers into five samples spanning the range of flux -0.05 < F<0.45. Tests on a smaller sample of high-resolution spectra show that our three strongest absorption bins would probe circumgalactic regions (projected separation < 300 proper kpc and |Delta v| < 300km/s) in about 60% of cases for very high signal-to-noise ratio. Within this subset, weakening Lya absorption is associated with decreasing purity of circumgalactic selection once BOSS noise is included. Our weaker two Lya absorption samples are dominated by the intergalactic medium. We present composite spectra of these samples and a...

  18. Searching for Earth-mass planets around $\\alpha$ Centauri: precise radial velocities from contaminated spectra

    CERN Document Server

    Bergmann, Christoph; Hearnshaw, John B; Wittenmyer, Robert A; Wright, Duncan J

    2014-01-01

    This work is part of an ongoing project which aims to detect terrestrial planets in our neighbouring star system $\\alpha$ Centauri using the Doppler method. Owing to the small angular separation between the two components of the $\\alpha$ Cen AB binary system, the observations will to some extent be contaminated with light coming from the other star. We are accurately determining the amount of contamination for every observation by measuring the relative strengths of the H-$\\alpha$ and NaD lines. Furthermore, we have developed a modified version of a well established Doppler code that is modelling the observations using two stellar templates simultaneously. With this method we can significantly reduce the scatter of the radial velocity measurements due to spectral cross-contamination and hence increase our chances of detecting the tiny signature caused by potential Earth-mass planets. After correcting for the contamination we achieve radial velocity precision of $\\sim 2.5\\,\\mathrm{m\\,s^{-1}}$ for a given night...

  19. The quiet time spectra of low energy hydrogen and helium nuclei. [suggesting protons and alphas of solar origin

    Science.gov (United States)

    Mewaldt, R. A.; Stone, E. C.; Vogt, R. E.

    1975-01-01

    Measurements of the 1972-1973 quiet time hydrogen and helium spectra from 1.3-40 MeV/nuc are discussed. For both spectra the relative-intensity minimum occurs at lower energies than those reported for earlier years. There is no evidence of a low energy turnup in the He spectrum down to 2.4 MeV/nuc. The spectra indicate that the galactic component dominates down to about 10 MeV; a stable, non-solar He-4 component extends from higher energies down to about 2.4 MeV/nuc. At lower energies the periods of minimum H and He intensity do not coincide, and the relative abundance of H and He at 1.3-2.3 MeV/nuc is variable, with H/He ratios ranging from about 3 to about 10. The observations suggest that the 1.3-2.3 MeV/nuc protons and alphas are of solar origin.

  20. Using k-alpha emission to determine fast electron spectra using the Hybrid code ZEPHYROS

    CERN Document Server

    White, Thomas; Gregori, Gianluca

    2014-01-01

    A high intensity laser-solid interaction invariably drives a non-thermal fast electron current through the target, however characterizing these fast electron distributions can prove difficult. An understanding of how these electrons propagate through dense materials is of fundamental interest and has applications relevant to fast ignition schemes and ion acceleration. Here, we utilize an upgraded version of the Hybrid code ZEPHYROS to demonstrate how the resulting k-alpha emission from such an interaction can be used as a diagnostic to obtain the characteristic temperature, divergence and total energy of the fast electron population.

  1. Radiative Transfer Modeling of Lyman Alpha Emitters: I. Statistics of Spectra and Luminosity

    CERN Document Server

    Zheng, Zheng; Trac, Hy; Miralda-Escude, Jordi

    2009-01-01

    We combine a cosmological reionization simulation with box size of 100Mpc/h on a side and a Monte Carlo Lyman-alpha (Lya) radiative transfer code to model Lyman Alpha Emitters (LAEs) at z~5.7. The model introduces Lya radiative transfer as the single factor for transforming the intrinsic Lya emission properties into the observed ones. Spatial diffusion of Lya photons from radiative transfer results in extended Lya emission and only the central part with high surface brightness can be observed. Because of radiative transfer, the appearance of LAEs depends on density and velocity structures in circumgalactic and intergalactic media as well as the viewing angle, which leads to a broad distribution of apparent (observed) Lya luminosity for a given intrinsic Lya luminosity. Radiative transfer also causes frequency diffusion of Lya photons. The resultant Lya line is asymmetric with a red tail. The peak of the Lya line shifts towards longer wavelength and the shift is anti-correlated with the apparent to intrinsic L...

  2. A Reverse Monte Carlo study of H+D Lyman alpha absorption from QSO spectra

    CERN Document Server

    Levshakov, S A; Takahara, F

    1997-01-01

    A new method based on a Reverse Monte Carlo [RMC] technique and aimed at the inverse problem in the analysis of interstellar (intergalactic) absorption lines is presented. The line formation process in chaotic media with a finite correlation length $(l > 0)$ of the stochastic velocity field (mesoturbulence) is considered. This generalizes the standard assumption of completely uncorrelated bulk motions $(l \\equiv 0)$ in the microturbulent approximation which is used for the data analysis up-to-now. It is shown that the RMC method allows to estimate from an observed spectrum the proper physical parameters of the absorbing gas and simultaneously an appropriate structure of the velocity field parallel to the line-of-sight. The application to the analysis of the H+D Ly$\\alpha$ profile is demonstrated using Burles & Tytler [B&T] data for QSO 1009+2956 where the DI Ly$\\alpha$ line is seen at $z_a = 2.504$. The results obtained favor a low D/H ratio in this absorption system, although our upper limit for the ...

  3. Estimation of {sup 3}J{sub HN-H{alpha}} and {sup 3}J{sub H}{alpha}{sub -H{beta}} coupling constants from heteronuclear TOCSY spectra

    Energy Technology Data Exchange (ETDEWEB)

    Pagano, Katiuscia; Fogolari, Federico, E-mail: ffogolari@mail.dstb.uniud.it; Corazza, Alessandra; Viglino, Paolo; Esposito, Gennaro [Universita di Udine, Dipartimento di Scienze e Tecnologie Biomediche (Italy)

    2007-11-15

    {sup 3}J proton-proton coupling constants bear information on the intervening dihedral angles. Methods have been developed to derive this information from NMR spectra of proteins. Using series expansion of the time dependent density matrix, and exploiting the simple topology of amino acid spin-systems, formulae for estimation of {sup 3}J{sub HN-H{alpha}} and {sup 3}J{sub H}{alpha}{sub -H{beta}} from HSQC-TOCSY spectra are derived. The results obtained on a protein entailing both {alpha}-helix and {beta}-sheet secondary structure elements agree very well with J-coupling constants computed from the X-ray structure. The method compares well with existing methods and requires only 2D spectra which would be typically otherwise recorded for structural studies.

  4. Study of 241 Am alpha spectra resolution using a ionization chamber with different grid types

    International Nuclear Information System (INIS)

    This paper describes some techniques used in the design of high resolution gridded ionization chambers for measurements of absolute activity of radionuclides. Details of the geometry of the system and its electrodes are presented; their shape and the spacing between the grid wire were studied. The experimental spectra obtained with an 241 Am source using 90% Ar and 10% C H4 as a flow gas show a total resolution of 39 KeV in very good agreement with best results available in the literature. (author). 17 refs., 2 figs., 3 tabs

  5. Searching for Dust Reddening in SDSS Spectra with Damped Lyman $\\alpha${} Systems

    CERN Document Server

    Frank, S

    2010-01-01

    We searched for evidence of reddening of background SDSS QSO spectra due to dust in intervening DLA systems. We utilise the Data Releases 5 and 7 to arrive at sample sizes of 475 (DR5) and 676 (DR7) absorbers, based on two different published lists of SDSS DLAs. Both samples span roughly the redshift range of 2.2 =-0.0013+-0.0025 (DR5) and =-0.0017+-0.0022 (DR7). Interestingly, when applying our technique to the samples of York et. al. (2006), vandenBerk et al. (2008) (intervening and intrinsic MgII absorbers) and the smaller DLA-subsample and pool of comparison QSOs of Vladilo et al. (2008), we do recover their results, i.e. detect the same amount of reddening as these authors do. Furthermore, we have tested whether subsamples of our la rge sample in categories involving the absorbers (HI column densities, presence or absence of accompanying metal absorption, absorber redshift) or the background quasars (emission redshift, brightness) do reveal dust extinction, but found no trends. These results are at odd...

  6. Study of the terahertz spectra of crystalline materials using NDDO semi-empirical methods: polyethylene, poly(vinylidene fluoride) form II and $\\alpha$-D-glucose

    CERN Document Server

    Chamorro-Posada, P

    2016-01-01

    Semi-empirical quantum chemistry methods offer a very interesting compromise between accuracy and computational load. In order to assess the performance of NDDO methods in the interpretation of terahertz spectra, the low frequency vibration modes of three crystalline materials, namely, polyethylene, poly(vinylidene fluoride) form II and $\\alpha$-D-glucose have been studied using the PM6 and PM7 Hamiltonians and the results have been compared with the experimental data and former calculations. The results show good qualitative or semi-quantitative agreement with the experimentally observed terahertz spectra.

  7. Measuring chemical evolution and gravitational dependence of \\alpha using ultraviolet Fe V and Ni V transitions in white-dwarf spectra

    CERN Document Server

    Ong, A; Flambaum, V V

    2013-01-01

    In this paper, we present the details of the ab initio high-precision configuration interaction and many-body perturbation theory calculations that were used in a previous work to place limits on the dependence of the fine-structure constant, alpha, on the gravitational field of the white-dwarf star G191-B2B. These calculations were combined with laboratory wavelengths and spectra from the Hubble Space Telescope Imaging Spectrograph to obtain limits on the gravitational alpha-dependence using Fe V and Ni V transitions. The uncertainty in these results are dominated by the uncertainty in the laboratory wavelengths. In this work we also present ab initio calculations of the isotopic shifts of the Fe V transitions. We show that improved laboratory spectra will enable determination of the relative isotope abundances in Fe V to an accuracy ~20%. Therefore this work provides a strong motivation for new laboratory measurements.

  8. Parametrization, molecular dynamics simulation and calculation of electron spin resonance spectra of a nitroxide spin label on a poly-alanine alpha helix

    OpenAIRE

    Sezer, Deniz; Freed, Jack H.; Roux, Benoît

    2008-01-01

    The nitroxide spin label 1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl-methanethiosulfonate (MTSSL), commonly used in site-directed spin labeling of proteins, is studied with molecular dynamics (MD) simulations. After developing force field parameters for the nitroxide moiety and the spin label linker, we simulate MTSSL attached to a poly-alanine alpha helix in explicit solvent to elucidate the factors affecting its conformational dynamics. Electron spin resonance spectra at 9 and 250 GHz are ...

  9. The Local Ly-alpha Forest IV: STIS G140M Spectra and Results on the Distribution and Baryon Content of HI Absorbers

    CERN Document Server

    Penton, S V; Shull, J M; Penton, Steven V.; Stocke, John T.

    2004-01-01

    We present HST STIS/G140M spectra of 15 extragalactic targets, which we combine with GHRS/G160M data to examine the statistical properties of the low-z Ly-alpha forest. We evaluate the physical properties of these Ly-alpha absorbers and compare them to their high-z counterparts. We determine that the warm, photoionized IGM contains 29+/-4% of the total baryon inventory at z = 0. We derive the distribution in column density, N_HI^(1.65+/-0.07) for 12.5 14.5. The slowing of the number density evolution of high-W Ly-alpha clouds is not as great as previously measured, and the break to slower evolution may occur later than previously suggested (z~1.0 rather than 1.6). We find a 7.2sigma excess in the two-point correlation function (TPCF) of Ly-alpha absorbers for velocity separations less than 260 km/s, which is exclusively due to the higher column density clouds. From our previous result that higher column density Ly-alpha clouds cluster more strongly with galaxies, this TPCF suggests a physical difference betw...

  10. The Lyman-alpha forest at redshifts 0.1 -- 1.6: good agreement between a large hydrodynamic simulation and HST spectra

    CERN Document Server

    Paschos, Pascal; Tytler, David; Kirkman, David; Norman, Michael L

    2008-01-01

    We give a comprehensive statistical description of the Lyman-alpha absorption from the intergalactic medium in a hydrodynamic simulation at redshifts 0.1-1.6, the range of redshifts covered by HST spectra of QSOs. We use the ENZO code to make a 76 comoving Mpc cube simulation using 75 kpc cells, for a Hubble constant of 71 km/s/Mpc. The best prior work, by \\citet{dave99},used an SPH simulation in a 15.6 Mpc box with an effective resolution of 245 kpc and slightly different cosmological parameters. At redshifts z=2 this simulation is different from data. \\citet{tytler07b} found that the simulated spectra at z=2 have too little power on large scales, Lyman-alpha lines are too wide, there is a lack high column density lines, and there is a lack of pixels with low flux. Here we present statistics at z<1.6, including the flux distribution, the mean flux, the effective opacity, and the power and correlation of the flux. We also give statistics of the lyman alpha lines including the line width distribution, the c...

  11. Measurement of a 2D fast-ion velocity distribution function by tomographic inversion of fast-ion D-alpha spectra

    CERN Document Server

    Salewski, Mirko; Jacobsen, Asger Schou; Garcıa-Munoz, Manuel; Heidbrink, Bill; Korsholm, Soren Bang; Leipold, Frank; Madsen, Jens; Moseev, Dmitry; Nielsen, Stefan Kragh; Rasmussen, Jesper; Stejner, Morten; Tardini, Giovanni; Weiland, Markus

    2015-01-01

    We present the first measurement of a local fast-ion 2D velocity distribution function $f(v_\\parallel, v_\\perp)$. To this end, we heated a plasma in ASDEX Upgrade by neutral beam injection and measured spectra of fast-ion D-alpha (FIDA) light from the plasma center in three views simultaneously. The measured spectra agree very well with synthetic spectra calculated from a TRANSP/NUBEAM simulation. Based on the measured FIDA spectra alone, we infer $f(v_\\parallel, v_\\perp)$ by tomographic inversion. Salient features of our measurement of $f(v_\\parallel, v_\\perp)$ agree reasonably well with the simulation: the measured as well as the simulated $f(v_\\parallel, v_\\perp)$ are lopsided towards negative velocities parallel to the magnetic field, and they have similar shapes. Further, the peaks in the simulation of $f(v_\\parallel, v_\\perp)$ at full and half injection energies of the neutral beam also appear in the measurement at similar velocity-space locations. We expect that we can measure spectra in up to seven vi...

  12. Non-linearity issues and multiple ionization satellites in the PIXE portion of spectra from the Mars alpha particle X-ray spectrometer

    Science.gov (United States)

    Campbell, John L.; Heirwegh, Christopher M.; Ganly, Brianna

    2016-09-01

    Spectra from the laboratory and flight versions of the Curiosity rover's alpha particle X-ray spectrometer were fitted with an in-house version of GUPIX, revealing departures from linear behavior of the energy-channel relationships in the low X-ray energy region where alpha particle PIXE is the dominant excitation mechanism. The apparent energy shifts for the lightest elements present were attributed in part to multiple ionization satellites and in part to issues within the detector and/or the pulse processing chain. No specific issue was identified, but the second of these options was considered to be the more probable. Approximate corrections were derived and then applied within the GUAPX code which is designed specifically for quantitative evaluation of APXS spectra. The quality of fit was significantly improved. The peak areas of the light elements Na, Mg, Al and Si were changed by only a few percent in most spectra. The changes for elements with higher atomic number were generally smaller, with a few exceptions. Overall, the percentage peak area changes are much smaller than the overall uncertainties in derived concentrations, which are largely attributable to the effects of rock heterogeneity. The magnitude of the satellite contributions suggests the need to incorporate these routinely in accelerator-based PIXE using helium beams.

  13. Primordial Non-Gaussianity in the Forest: 3D Bispectrum of Ly-alpha Flux Spectra Along Multiple Lines of Sight

    CERN Document Server

    Hazra, Dhiraj Kumar

    2012-01-01

    We investigate the possibility of constraining primordial non-Gaussianity using the 3D bispectrum of Ly-alpha forest. The strength of the quadratic non-Gaussian correction to an otherwise Gaussian primordial gravitational field is assumed to be dictated by a single parameter fnl. We present the first prediction for bounds on fnl using Ly-alpha flux spectra along multiple lines of sight. The 3D Ly-$\\alpha$ transmitted flux field is modeled as a biased tracer of the underlying matter distribution sampled along 1D skewers corresponding to quasars sight lines. The precision to which fnl can be constrained depends on the survey volume, pixel noise and aliasing noise (arising from discrete sampling of the density field). We consider various combinations of these factors to predict bounds on fnl. We find that in an idealized situation of full sky survey and negligible Poisson noise one may constrain fnl ~ 23 in the equilateral limit. Assuming a Ly-alpha survey covering large parts of the sky (k_{min} = 8 * 10^{-4} M...

  14. The Lyman-alpha forest of a Lyman Break Galaxy: VLT Spectra of MS1512-cB58 at z=2.724

    OpenAIRE

    Savaglio, S.; Panagia, N.; Padovani, P.

    2001-01-01

    The high redshift galaxy MS1512-cB58 (z=2.724, m_V=20.64) has been observed with the very efficient high resolution echelle spectrograph VLT/UVES. Although this is a very challenging observational program for a Southern hemisphere telescope (the galaxy is located at +36 deg declination), high resolution spectra (FWHM ~ 26 km/s) have revealed, with unprecedented detail along a galaxy sight line, the Lyman-alpha forest due to intervening clouds in the intergalactic medium (IGM). The mean depres...

  15. SOURCES 4A: A Code for Calculating (alpha,n), Spontaneous Fission, and Delayed Neutron Sources and Spectra

    International Nuclear Information System (INIS)

    SOURCES 4A is a computer code that determines neutron production rates and spectra from (α,n) reactions, spontaneous fission, and delayed neutron emission due to the decay of radionuclides. The code is capable of calculating (α,n) source rates and spectra in four types of problems: homogeneous media (i.e., a mixture of α-emitting source material and low-Z target material), two-region interface problems (i.e., a slab of α-emitting source material in contact with a slab of low-Z target material), three-region interface problems (i.e., a thin slab of low-Z target material sandwiched between α-emitting source material and low-Z target material), and (α,n) reactions induced by a monoenergetic beam of α-particles incident on a slab of target material. Spontaneous fission spectra are calculated with evaluated half-life, spontaneous fission branching, and Watt spectrum parameters for 43 actinides. The (α,n) spectra are calculated using an assumed isotropic angular distribution in the center-of-mass system with a library of 89 nuclide decay α-particle spectra, 24 sets of measured and/or evaluated (α,n) cross sections and product nuclide level branching fractions, and functional α-particle stopping cross sections for Z < 106. The delayed neutron spectra are taken from an evaluated library of 105 precursors. The code outputs the magnitude and spectra of the resultant neutron source. It also provides an analysis of the contributions to that source by each nuclide in the problem

  16. The Lyman-alpha forest of a Lyman Break Galaxy VLT Spectra of MS1512-cB58 at z=2.724

    CERN Document Server

    Savaglio, S; Padovani, P

    2001-01-01

    The high redshift galaxy MS1512-cB58 (z=2.724, m_V=20.64) has been observed with the very efficient high resolution echelle spectrograph VLT/UVES. Although this is a very challenging observational program for a Southern hemisphere telescope (the galaxy is located at +36 deg declination), high resolution spectra (FWHM ~ 26 km/s) have revealed, with unprecedented detail along a galaxy sight line, the Lyman-alpha forest due to intervening clouds in the intergalactic medium (IGM). The mean depression D_A due to IGM absorption blueward of the galaxy Ly-alpha wavelength and the number density dn/dz of Ly-alpha clouds have been compared with equivalent results obtained for QSO sight lines at similar redshifts. Our results indicate a possible excess of absorption close to the galaxy. The mean depression at ~ 150 h_65^-1 Mpc comoving (Omega_m=0.3, Omega_Lambda=0.7) from the galaxy is D_A=0.36+/-0.03, to be compared with 0.22+/-0.04, expected from a best fit to QSO sight lines. In the same region (z=2.610), the number ...

  17. The MUSCLES Treasury Survey II: Intrinsic Lyman Alpha and Extreme Ultraviolet Spectra of K and M Dwarfs with Exoplanets

    CERN Document Server

    Youngblood, Allison; Loyd, R O Parke; Linsky, Jeffrey L; Redfield, Seth; Schneider, P Christian; Wood, Brian E; Brown, Alexander; Froning, Cynthia; Miguel, Yamila; Rugheimer, Sarah; Walkowicz, Lucianne

    2016-01-01

    The ultraviolet (UV) spectral energy distributions of low-mass (K- and M-type) stars play a critical role in the heating and chemistry of exoplanet atmospheres, but are not observationally well-constrained. Direct observations of the intrinsic flux of the Lyman alpha line (the dominant source of UV photons from low-mass stars) are challenging, as interstellar HI absorbs the entire line core for even the closest stars. To address the existing gap in empirical constraints on the UV flux of K and M dwarfs, the MUSCLES HST Treasury Survey has obtained UV observations of 11 nearby M and K dwarfs hosting exoplanets. This paper presents the Lyman alpha and extreme-UV spectral reconstructions for the MUSCLES targets. Most targets are optically inactive, but all exhibit significant UV activity. We use a Markov Chain Monte Carlo technique to correct the observed Lyman alpha profiles for interstellar absorption, and we employ empirical relations to compute the extreme-UV spectral energy distribution from the intrinsic L...

  18. Abundances of Baade's Window Giants from Keck/HIRES Spectra: II. The Alpha- and Light Odd Elements

    CERN Document Server

    Fulbright, J P; Rich, R M; Fulbright, Jon. P.; William, Andrew Mc

    2006-01-01

    We report detailed chemical abundance analysis of 27 RGB stars towards the Galactic bulge in Baade's Window for elements produced by massive stars: O, Na, Mg, Al, Si, Ca and Ti. All of these elements are overabundant in the bulge relative to the disk, especially Mg, indicating that the bulge is enhanced in Type~II supernova ejecta and most likely formed more rapidly than the disk. We attribute a rapid decline of [O/Fe] to metallicity-dependent yields of oxygen in massive stars, perhaps connected to the Wolf-Reyet phenomenon. he explosive nucleosynthesis alphas, Si, Ca and Ti, possess identical trends with [Fe/H], consistent with their putative common origin. We note that different behaviors of hydrostatic and explosive alpha elements can be seen in the stellar abundances of stars in Local Group dwarf galaxies. We also attribute the decline of Si,Ca and Ti relative to Mg, to metallicity- dependent yields for the explosive alpha elements from Type~II supernovae. The starkly smaller scatter of [/Fe] with [Fe/H] ...

  19. MULTI-ELEMENT ABUNDANCE MEASUREMENTS FROM MEDIUM-RESOLUTION SPECTRA. IV. ALPHA ELEMENT DISTRIBUTIONS IN MILKY WAY SATELLITE GALAXIES

    International Nuclear Information System (INIS)

    We derive the star formation histories of eight dwarf spheroidal (dSph) Milky Way satellite galaxies from their alpha element abundance patterns. Nearly 3000 stars from our previously published catalog comprise our data set. The average [α/Fe] ratios for all dSphs follow roughly the same path with increasing [Fe/H]. We do not observe the predicted knees in the [α/Fe] versus [Fe/H] diagram, corresponding to the metallicity at which Type Ia supernovae begin to explode. Instead, we find that Type Ia supernova ejecta contribute to the abundances of all but the most metal-poor ([Fe/H] < -2.5) stars. We have also developed a chemical evolution model that tracks the star formation rate, Types II and Ia supernova explosions, and supernova feedback. Without metal enhancement in the supernova blowout, massive amounts of gas loss define the history of all dSphs except Fornax, the most luminous in our sample. All six of the best-fit model parameters correlate with dSph luminosity but not with velocity dispersion, half-light radius, or Galactocentric distance.

  20. Characteristics of the Fe II and C II emission in high-resolution IUE spectra (2300-3000 A) of Alpha Orionis

    Science.gov (United States)

    Carpenter, K. G.

    1984-01-01

    A study is presented of Fe II and C II emission features in the 2300-3000 A region of four high-resolution IUE spectra of Alpha Ori obtained during the period 1978 April-1982 November. A set of 42 unmutilated, unblended Fe II lines of multiplets UV 1-3, 32-33, 35-36, and 60-64 and the C II (UV 0.01) intercombination lines have been identified and measured to determine their velocities, fluxes, and asymmetries. A correlation of Fe II line asymmetry with intrinsic line strength indicates a velocity field which is initially constant, then algebraically increases with radius to a maximum value and then decreases significantly before reaching an asymptotic flow speed far from the star. The mean velocity of the chromospheric regions emitting Fe II does not appear to differ substantially from the time-average of the photospheric velocity, but there is evidence that the two regions are not strongly coupled and thus that the chromosphere does not strictly follow the semiperiodic 6 year pulsations of the photosphere. An analysis of the C II line fluxes produces estimates of the electron density in the chromosphere in the range 3.2 x 10 to the 7th-1.3 x 10 to the 8th per sq cm and indicates that the region emitting C II is geometrically thick, extending at least one-tenth, and perhaps as far as 1.2, photospheric radii from the base of the chromosphere.

  1. Measurement of a 2D fast-ion velocity distribution function by tomographic inversion of fast-ion D-alpha spectra

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Jacobsen, Asger Schou;

    2014-01-01

    We present the first measurement of a local fast-ion 2D velocity distribution function f(v‖, v⊥). To this end, we heated a plasma in ASDEX Upgrade by neutral beam injection and measured spectra of fast-ion Dα (FIDA) light from the plasma centre in three views simultaneously. The measured spectra ...

  2. Alpha-n and spontaneous fission sources and spectra from individual plutonium isotopes in PuF4 and PuO2

    International Nuclear Information System (INIS)

    Plutonium-containing compounds vary widely in isotopic content, and as a result, the dose as function of isotopic content also varies considerably. Determination of the dose from neutrons, decay and capture gammas from plutonium in the form of compounds thus requires that the spontaneous fission and (α,n) source and spectra from each individual isotope be known. To facilitate dose calculations from plutonium-containing compounds, we have calculated the spontaneous fission and (α,n) sources and spectra for 1 g of each of the plutonium isotopes in the form of either PuF4 or PuO2. As 241Am is often a component in a mixture of plutonium isotopic compounds, the source and spectra from 1 g of 241Am mixed with PuF4 or PuO2 has also been determined. Using these results, the neutron source and spectra may be determined for any sample composition. 2 refs., 3 tabs

  3. Electronic spectra and photophysics of platinum(II) complexes with alpha-diimine ligands - Solid-state effects. I - Monomers and ligand pi dimers

    Science.gov (United States)

    Miskowski, Vincent M.; Houlding, Virginia H.

    1989-01-01

    Two types of emission behavior for Pt(II) complexes containing alpha-diimine ligands have been observed in dilute solution. If the complex also has weak field ligands such as chloride, ligand field (d-d) excited states become the lowest energy excited states. If only strong field ligands are present, a diimine 3(pi-pi/asterisk/) state becomes the lowest. In none of the cases studied did metal-to-ligand charge transfer excited state lie lowest.

  4. Oscillator strengths and radiative transition rates for K{sub {alpha}} lines in gold X-ray spectra: 1s-2p transitions

    Energy Technology Data Exchange (ETDEWEB)

    Nahar, Sultana N. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)], E-mail: nahar@astronomy.ohio-state.edu; Pradhan, Anil K.; Sur, Chiranjib [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)

    2008-07-15

    Oscillator strengths (f), line strengths (S) and radiative decay rates (A) are presented for all 1s-2p transitions in gold (Au) ions. X-ray emission from gold is extensively used, such as in fusion experiments, and in medical research for diagnostics and treatment. The K{sub {alpha}} 1s-2p transitions in gold are found to be in the hard X-ray region of 66-73 keV (0.1888-0.1706A) and are limited to from hydrogen-like to fluorine-like ions as the 2p subshell is filled beyond fluorine. While there are two 1s-2p transitions (1s{sup 2}S{sub 1/2}-2p{sup 2}P{sub 1/2}{sup o} and 1s{sup 2}S{sub 1/2}-2p{sup 2}P{sub 3/2}{sup o}) for hydrogen-like gold, Au{sup +78}, the number varies depending on the number of electrons in the 2p subshell before and after the transition. For example, there are 35 1s-2p transitions giving the same number of K{sub {alpha}} lines for carbon-like Au, Au{sup +73}. The transitions can be of both types, dipole allowed and intercombination, and are in general strong, that is, A{approx}10{sup 16}/s. However, there are also weak transitions in the set. The present results are obtained from configuration interaction atomic structure calculations using the code SUPERSTRUCTURE which includes relativistic effects in Breit-Pauli approximation. The results have been benchmarked for a few ionic states with other detailed relativistic approaches, such as Dirac-Fock and coupled cluster. Comparisons with the very few transitions in the literature as well as those from other approaches indicate reasonable accuracy for the present results.

  5. Function spectra and continuous G-spectra

    CERN Document Server

    Davis, Daniel

    2011-01-01

    Let G be a profinite group, {X_alpha}_alpha a cofiltered diagram of discrete G-spectra, and Z a spectrum with trivial G-action. We show how to define the homotopy fixed point spectrum F(Z, holim_alpha X_alpha)^{hG} and that when G has finite virtual cohomological dimension (vcd), it is equivalent to F(Z, holim_alpha (X_alpha)^{hG}). With these tools, we show that the K(n)-local Spanier-Whitehead dual is always a homotopy fixed point spectrum, a well-known Adams-type spectral sequence is actually a descent spectral sequence, and, for a sufficiently nice k-local profinite G-Galois extension E, with K a closed normal subgroup of G, the equivalence (E^{h_kK})^{h_kG/K} \\simeq E^{h_kG} (due to Behrens and the author), where (-)^{h_k(-)} denotes k-local homotopy fixed points, can be upgraded to an equivalence that just uses ordinary (non-local) homotopy fixed points, when G/K has finite vcd.

  6. Coefficient Alpha

    OpenAIRE

    Panayiotis Panayides

    2013-01-01

    Heavy reliance on Cronbach’s alpha has been standard practice in many validation studies. However, there seem to be two misconceptions about the interpretation of alpha. First, alpha is mistakenly considered as an indication of unidimensionality and second, that the higher the value of alpha the better. The aim of this study is to clarify these misconceptions with the use of real data from the educational setting. Results showed that high alpha values can be obtained in multidimensional scale...

  7. Alpha spectral analysis via artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Kangas, L.J.; Hashem, S.; Keller, P.E.; Kouzes, R.T. [Pacific Northwest Lab., Richland, WA (United States); Troyer, G.L. [Westinghouse Hanford Co., Richland, WA (United States)

    1994-10-01

    An artificial neural network system that assigns quality factors to alpha particle energy spectra is discussed. The alpha energy spectra are used to detect plutonium contamination in the work environment. The quality factors represent the levels of spectral degradation caused by miscalibration and foreign matter affecting the instruments. A set of spectra was labeled with a quality factor by an expert and used in training the artificial neural network expert system. The investigation shows that the expert knowledge of alpha spectra quality factors can be transferred to an ANN system.

  8. Alpha spectral analysis via artificial neural networks

    International Nuclear Information System (INIS)

    An artificial neural network system that assigns quality factors to alpha particle energy spectra is discussed. The alpha energy spectra are used to detect plutonium contamination in the work environment. The quality factors represent the levels of spectral degradation caused by miscalibration and foreign matter affecting the instruments. A set of spectra was labeled with a quality factor by an expert and used in training the artificial neural network expert system. The investigation shows that the expert knowledge of alpha spectra quality factors can be transferred to an ANN system

  9. BETA SPECTRA. I. Negatrons spectra

    International Nuclear Information System (INIS)

    Using the Fermi theory of beta decay, the beta spectra for 62 negatrons emitters have been computed introducing a correction factor for unique forbidden transitions. These spectra are plotted vs. energy, once normal i sed, and tabulated with the related Fermi functions. The average and median energies are calculated. (Author)

  10. FTIR spectra

    Czech Academy of Sciences Publication Activity Database

    Machovič, Vladimír; Novák, František; Madronová, L.; Novák, J.

    New York : Nova Science Publisher, 2011 - (Madronová, L.), s. 21-33 ISBN 978-1-61668-965-0. - ( Chemistry Research and Applications) Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z60660521 Keywords : FTIR spectra * humic acids * soil Subject RIV: DB - Geology ; Mineralogy

  11. Alpha fetoprotein

    Science.gov (United States)

    Fetal alpha globulin; AFP ... Greater than normal levels of AFP may be due to: Cancer in testes , ovaries, biliary (liver secretion) tract, stomach, or pancreas Cirrhosis of the liver Liver cancer ...

  12. Dipole oscillation modes in $\\alpha$-clustering light nuclei

    CERN Document Server

    He, W B; Cao, X G; Cai, X Z; Zhang, G Q

    2016-01-01

    The alpha cluster states are discussed in an extended quantum molecular dynamics (EQMD) model frame. Different alpha cluster structures are studied in details, such as $^8$Be two-alpha cluster structure, $^{12}$C triangle structure, $^{12}$C chain structure, $^{16}$O chain structure, $^{16}$O kite structure, and $^{16}$O square structure. The properties like width of wave packets for different alpha clusters, momentum distribution, and the binding energy among alpha clusters are studied. It is also discussed how the $\\alpha$ cluster degree of freedom affects nuclear collective vibrations. The different $\\alpha$ cluster configurations in $^{12}$C and $^{16}$O have corresponding characteristic spectra of GDR and the coherence of different alpha clusters's dipole oscillation are described in details. The number and centroid energies of peaks in the GDR spectra can be reasonably explained by the geometrical and dynamical symmetries of $\\alpha$-clustering configurations. The GDR can be regarded as a very effective...

  13. The Behaviour of Varying-Alpha Cosmologies

    CERN Document Server

    Barrow, John D; Magueijo, J

    2002-01-01

    We determine the behaviour of a time-varying fine structure 'constant' $\\alpha (t)$ during the early and late phases of universes dominated by the kinetic energy of changing $\\alpha (t)$, radiation, dust, curvature, and lambda, respectively. We show that after leaving an initial vacuum-dominated phase during which $\\alpha$ increases, $\\alpha$ remains constant in universes like our own during the radiation era, and then increases slowly, proportional to a logarithm of cosmic time, during the dust era. If the universe becomes dominated by negative curvature or a positive cosmological constant then $\\alpha$ tends rapidly to a constant value. The effect of an early period of de Sitter or power-law inflation is to drive $\\alpha$ to a constant value. Various cosmological consequences of these results are discussed with reference to recent observational studies of the value of $\\alpha$ from quasar absorption spectra and to the existence of life in expanding universes.

  14. Spectra of radioactive nuclides radiation, measured with semiconductor detectors. 2

    International Nuclear Information System (INIS)

    The second part of the atlas 'Radiation spectra of radionuclides measured with semiconductor detectors' is presented including 259 spectra of 126 alpha, beta, gamma, and X ray emitters. Some spectra of the first part of the atlas are given at another scale and sometimes for other energy ranges. The total number of investigated radionuclides amounts to 261 of which 69 are new ones

  15. Alpha particles energy straggling in noble gases

    International Nuclear Information System (INIS)

    The comparison of the calculated spectra by the Monte-Carlo simulation with the experimental alpha-particles spectra after their passage through noble gases target has good agreement for Ar, Kr, and Xe and significant deviation for He and Ne. These agreement or disagreement of the calculated and experimental spectra were ascribed to adequacy or inadequacy of the applied Bohr's charged particles energy loss formula for the specific medium. (author)

  16. $\\alpha_s$ review (2016)

    CERN Document Server

    d'Enterria, David

    2016-01-01

    The current world-average of the strong coupling at the Z pole mass, $\\alpha_s(m^2_{Z}) = 0.1181 \\pm 0.0013$, is obtained from a comparison of perturbative QCD calculations computed, at least, at next-to-next-to-leading-order accuracy, to a set of 6 groups of experimental observables: (i) lattice QCD "data", (ii) $\\tau$ hadronic decays, (iii) proton structure functions, (iv) event shapes and jet rates in $e^+e^-$ collisions, (v) Z boson hadronic decays, and (vi) top-quark cross sections in p-p collisions. In addition, at least 8 other $\\alpha_s$ extractions, usually with a lower level of theoretical and/or experimental precision today, have been proposed: pion, $\\Upsilon$, W hadronic decays; soft and hard fragmentation functions; jets cross sections in pp, e-p and $\\gamma$-p collisions; and photon F$_2$ structure function in $\\gamma\\,\\gamma$ collisions. These 14 $\\alpha_s$ determinations are reviewed, and the perspectives of reduction of their present uncertainties are discussed.

  17. Test chamber for alpha spectrometry

    Science.gov (United States)

    Larsen, Robert P.

    1977-01-01

    Alpha emitters for low-level radiochemical analysis by measurement of alpha spectra are positioned precisely with respect to the location of a surface-barrier detector by means of a chamber having a removable threaded planchet holder. A pedestal on the planchet holder holds a specimen in fixed engagement close to the detector. Insertion of the planchet holder establishes an O-ring seal that permits the chamber to be pumped to a desired vacuum. The detector is protected against accidental contact and resulting damage.

  18. The $\\alpha-\\alpha$ fishbone potential revisited

    CERN Document Server

    Day, J P; Elhanafy, M; Smith, E; Woodhouse, R; Papp, Z

    2011-01-01

    The fishbone potential of composite particles simulates the Pauli effect by nonlocal terms. We determine the $\\alpha-\\alpha$ fishbone potential by simultaneously fitting to two-$\\alpha$ resonance energies, experimental phase shifts and three-$\\alpha$ binding energies. We found that essentially a simple gaussian can provide a good description of two-$\\alpha$ and three-$\\alpha$ experimental data without invoking three-body potentials.

  19. Alpha One Foundation

    Science.gov (United States)

    ... Tested Find Support Find Doctor What Is Alpha-1? Alpha-1 Antitrypsin Deficiency (Alpha-1) is a ... results for inhaled augmentation More News Our Number One Goal: Find a cure for Alpha-1. Website ...

  20. Alpha-1 Antitrypsin Test

    Science.gov (United States)

    ... helpful? Also known as: Alpha 1 -antitrypsin; A1AT; AAT Formal name: Alpha 1 Antitrypsin; α1-antitrypsin Related ... know? How is it used? Alpha-1 antitrypsin (AAT) testing is used to help diagnose alpha-1 ...

  1. Alpha spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Felix; Wilsenach, Heinrich; Zuber, Kai [IKTP TU-Dresden, Dresden (Germany)

    2014-07-01

    Alpha decays from long living isotopes are one of the limiting backgrounds for experiments searching for rare decays with stringent background constrains, such as neutrinoless double beta decay experiments. It is thus very important to accurately measure the half-lives of these decays, in order to properly model their background contribution. Therefore, it is important to be able to measure half-lives from alpha decays of the order of 1 x 10{sup 15} yr. A measurement of such a long lived decay imposes, however, a series of challenges, where the correct discrimination between background and true signal is critical. There is also a more general interest in such long living half-life measurements, as their value depends crucially on the underlying nuclear model. This work proposes a setup to measure long lived alpha decays, based on the design of the Frisch-Grid ionisation chamber. It is shown that the proposed design provides a good separation of signal and background events. It is also demonstrated that, with pulse shape analysis, it is possible to constrain the source position of the decay, further improving the quality of the data. A discussion of the characterisation of the detector is also presented as well as some results obtained with calibration sources.

  2. Alpha spectroscopy

    International Nuclear Information System (INIS)

    Alpha decays from long living isotopes are one of the limiting backgrounds for experiments searching for rare decays with stringent background constrains, such as neutrinoless double beta decay experiments. It is thus very important to accurately measure the half-lives of these decays, in order to properly model their background contribution. Therefore, it is important to be able to measure half-lives from alpha decays of the order of 1 x 1015 yr. A measurement of such a long lived decay imposes, however, a series of challenges, where the correct discrimination between background and true signal is critical. There is also a more general interest in such long living half-life measurements, as their value depends crucially on the underlying nuclear model. This work proposes a setup to measure long lived alpha decays, based on the design of the Frisch-Grid ionisation chamber. It is shown that the proposed design provides a good separation of signal and background events. It is also demonstrated that, with pulse shape analysis, it is possible to constrain the source position of the decay, further improving the quality of the data. A discussion of the characterisation of the detector is also presented as well as some results obtained with calibration sources.

  3. Direct Alpha Analysis for Forensic Samples (DAAFS)

    International Nuclear Information System (INIS)

    The goal of the DAAFS project is to deliver a field deployable direct alpha sample spectrometry system. This system is designed to rectify current gaps in pure alpha emitting material detection. The system comprises, firstly, an evaluation of multiple innovative methods for rapid on-site sample collection of difficult to detect alpha RN contamination. Secondly, the incorporation of an experimental alpha spectrometry analysis software suite, 'ADAM', is provided for performing the required on-site deconvolution of the complex alpha spectra arising from the direct sample measurement. Software simulation of collected alpha spectra will be handled by 'AASI', which will simulate alpha spectra as a training and analysis verification tool. Thirdly, a Concept of Operations (ConOps) for the system implementation in RN field teams is included. This combination of the swipe methodology, advanced swipe treatment equipment, mobile field laboratories, and the state of the art analysis software suite will provide RN response teams with the capability to identify and rapidly (i.e., hours as opposed to days) quantify low activity and difficult to detect alpha emitters. Further expert analysis support is available to field teams by sharing of raw spectral data via email with off-site laboratories. The proposed system provides the solution to this identified capability gap, specifically, a field-deployable real-time alpha detection system. The system comprises: a non-destructive particle sampler, standardized swipe sampling methods, a self-contained field alpha spectrometry system and an integrated data management/communications tool allowing for real-time raw-data tracking and data sharing. This system also provides responders with the type/quantity of RN material for improved safeguards, forensics, and contamination mitigation applications. (author)

  4. Functional Regression for Quasar Spectra

    CERN Document Server

    Ciollaro, Mattia; Freeman, Peter; Genovese, Christopher; Lei, Jing; O'Connell, Ross; Wasserman, Larry

    2014-01-01

    The Lyman-alpha forest is a portion of the observed light spectrum of distant galactic nuclei which allows us to probe remote regions of the Universe that are otherwise inaccessible. The observed Lyman-alpha forest of a quasar light spectrum can be modeled as a noisy realization of a smooth curve that is affected by a `damping effect' which occurs whenever the light emitted by the quasar travels through regions of the Universe with higher matter concentration. To decode the information conveyed by the Lyman-alpha forest about the matter distribution, we must be able to separate the smooth `continuum' from the noise and the contribution of the damping effect in the quasar light spectra. To predict the continuum in the Lyman-alpha forest, we use a nonparametric functional regression model in which both the response and the predictor variable (the smooth part of the damping-free portion of the spectrum) are function-valued random variables. We demonstrate that the proposed method accurately predicts the unobserv...

  5. {alpha}- and {beta}-Na{sub 2}[BH{sub 4}][NH{sub 2}]: Two modifications of a complex hydride in the system NaNH{sub 2}-NaBH{sub 4}; syntheses, crystal structures, thermal analyses, mass and vibrational spectra

    Energy Technology Data Exchange (ETDEWEB)

    Somer, Mehmet, E-mail: msomer@ku.edu.t [Koc University, Chemistry Department, Sariyer, Istanbul (Turkey); Acar, Selcuk; Koz, Cevriye; Kokal, Ilkin [Koc University, Chemistry Department, Sariyer, Istanbul (Turkey); Hoehn, Peter; Cardoso-Gil, Raul; Aydemir, Umut [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Akselrud, Lev [Ivan Franco National University, Department of Inorganic Chemistry, Lviv (Ukraine)

    2010-02-18

    The title compound Na{sub 2}[BH{sub 4}][NH{sub 2}]{identical_to}Na{sub 2}BNH{sub 6} exists in two different modifications: the low-temperature (LT) {beta}- and the high-temperature (HT) {alpha}-phase. The HT {alpha}-Na{sub 2}BNH{sub 6} is accessible by single heating of the binaries NaNH{sub 2} and NaBH{sub 4} (molar ratio = 1:1) to the melting point of 492 K for 1 h in evacuated Pyrex ampoules. On longer annealing (T = 342 K, 10 days), the HT {alpha}-phase converts completely to the LT {beta}-phase. The {beta} {yields} {alpha} transition at 371 K is very fast, but the conversion {alpha} {yields} {beta} is quite slow. No further phase formation was detected in the system up to a molar ratio of 5:1 (NaNH{sub 2}:NaBH{sub 4}). The cubic {alpha}-Na{sub 2}BNH{sub 6} crystallizes in the K{sub 3}SO{sub 4}F-type of structure (space group: Pm3-barm, Z = 1) with a = 4.6950(1) A. {beta}-Na{sub 2}BNH{sub 6} crystallizes in orthorhombic symmetry (space group: Pbcm, Z = 4) with a = 6.5384(2) A, b = 6.4960(1) A, c = 9.8512(2) A. Both structures can directly be derived from the perovskite type structure ABO{sub 3}, with the [BH{sub 4}]{sup -} and [NH{sub 2}]{sup -} moieties in the A and B sites, respectively. The charge balancing Na ions are occupying 2/3 of the O positions. In both cases, the presence of the two different anions in the solids was also confirmed by vibrational spectra. According to DTA and high temperature X-ray diffraction (HT-XRD) measurements, the educts NaNH{sub 2} and NaBH{sub 4} react at 430 K to form {alpha}-Na{sub 2}BNH{sub 6} which remains stable until the melting point of 492 K. Between 492 and 573 K, no significant effects were detected in DTA and TG. Above 573 K, however, a sudden decomposition takes place in two steps (659 and 689 K) causing a total mass loss of 8%. The gaseous species formed during the decomposition process were followed by mass spectra (MS). The mass spectra obtained from 1:1 and 2:1 mixtures of NaNH{sub 2} and NaBH{sub 4} in the

  6. The Chemical Enrichment History of Damped Lyman-alpha Galaxies

    OpenAIRE

    Lu, Limin; Sargent, Wallace L. W.; Barlow, Thomas A.

    1996-01-01

    Studies of damped Lyman-alpha absorption systems in quasar spectra are yielding very interesting results regarding the chemical evolution of these galaxies. We present some preliminary results from such a program.

  7. Janus spectra in two-dimensional flows

    CERN Document Server

    Liu, Chien-Chia; Chakraborty, Pinaki

    2016-01-01

    In theory, large-scale atmospheric flows, soap-film flows and other two-dimensional flows may host two distinct types of turbulent energy spectra---in one, $\\alpha$, the spectral exponent of velocity fluctuations, equals $3$ and the fluctuations are dissipated at the small scales, and in the other, $\\alpha=5/3$ and the fluctuations are dissipated at the large scales---but measurements downstream of obstacles have invariably revealed $\\alpha = 3$. Here we report experiments on soap-film flows where downstream of obstacles there exists a sizable interval in which $\\alpha$ has transitioned from $3$ to $5/3$ for the streamwise fluctuations but remains equal to $3$ for the transverse fluctuations, as if two mutually independent turbulent fields of disparate dynamics were concurrently active within the flow. This species of turbulent energy spectra, which we term the Janus spectra, has never been observed or predicted theoretically. Our results may open up new vistas in the study of turbulence and geophysical flows...

  8. Characteristic of the new scintillators for alpha radiation spectrometry

    International Nuclear Information System (INIS)

    In this paper authors present results of development of new glass scintillators for alpha radiation spectrometry. Physical and luminescence parameters of proposed scintillators are compared. Used materials and methods as well as alpha spectra of Rn-222, Po-218 and Po-214 are presented. (J.K.)

  9. Beta spectra. II-Positron spectra

    International Nuclear Information System (INIS)

    Using the Fermi theory of beta decay, the beta spectra for 30 positron emitters have been computed, introducing a correction factor for unique forbidden transitions. The spectra are ploted vs. energy, once normalised, and tabulated with the related Fermi functions. The average and median energies are calculated. (author)

  10. Flicker noise pulsar radio spectra

    CERN Document Server

    Krzeszowski, K; Słowikowska, A; Jessner, A

    2014-01-01

    We present new results of fitting 108 spectra of radio pulsars with the flicker noise model proposed by Loehmer et al. (2008) and compare them with the spectral indices of power-law fits published by Maron et al. (2000). The fits to the model were carried out using the Markov chain Monte Carlo (MCMC) method appropriate for the non-linear fits. Our main conclusion is that pulsar radio spectra can be statistically very well described by the flicker noise model over wide frequency range from a few tens of MHz up to tens of GHz. Moreover, our dataset allows us to conduct statistical analysis of the model parameters. As our results show, there is a strong negative correlation between the flicker noise spectrum model parameters log $S_0$ and $n$ and a strong positive relationship between n and the power-law spectral index $\\alpha$. The latter implies that their physical meaning is similar, however the flicker noise model has an advantage over broken power-law model. Not only it describes the spectra in higher frequ...

  11. High resolution alpha particle spectrometry through collimation

    International Nuclear Information System (INIS)

    Alpha particle spectrometry with collimation is a useful method for identifying nuclear materials among various nuclides. A mesh type collimator reduces the low energy tail and broadened energy distribution by cutting off particles with a low incidence angle. The relation between the resolution and the counting efficiency can be investigated by changing a ratio of the mesh hole diameter and the collimator thickness. Through collimation, a target particle can be distinguished by a PIPS® detector under a mixture of various nuclides. - Highlights: • Alpha particle spectrometry with collimation a useful method for identifying nuclear materials among various radionuclides. • A collimator cut off alpha particles with low angle emitted from a source. • We confirm that that a collimator improves the resolution of alpha spectra through both simulation and experiments

  12. Alpha spectrometry of thick sources. I. Application to alpha emitters determination

    International Nuclear Information System (INIS)

    A method for determining alpha emitters by silicon surface barrier detector spectroscopy using thick sources is studied. Two types of spectra have been obtained. They have different shapes of line according to the procedure used for preparing the sources. For both spectra a computing least square programme has been developed. In this way it is possible to calculate line intensities with accuracy better than 20 percent. (author)

  13. Ab initio alpha-alpha scattering.

    Science.gov (United States)

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G

    2015-12-01

    Processes such as the scattering of alpha particles ((4)He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei--nuclei with even and equal numbers of protons and neutrons--is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the 'adiabatic projection method' to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of

  14. Ab initio alpha-alpha scattering

    Science.gov (United States)

    Elhatisari, Serdar; Lee, Dean; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A.; Luu, Thomas; Meißner, Ulf-G.

    2015-12-01

    Processes such as the scattering of alpha particles (4He), the triple-alpha reaction, and alpha capture play a major role in stellar nucleosynthesis. In particular, alpha capture on carbon determines the ratio of carbon to oxygen during helium burning, and affects subsequent carbon, neon, oxygen, and silicon burning stages. It also substantially affects models of thermonuclear type Ia supernovae, owing to carbon detonation in accreting carbon-oxygen white-dwarf stars. In these reactions, the accurate calculation of the elastic scattering of alpha particles and alpha-like nuclei—nuclei with even and equal numbers of protons and neutrons—is important for understanding background and resonant scattering contributions. First-principles calculations of processes involving alpha particles and alpha-like nuclei have so far been impractical, owing to the exponential growth of the number of computational operations with the number of particles. Here we describe an ab initio calculation of alpha-alpha scattering that uses lattice Monte Carlo simulations. We use lattice effective field theory to describe the low-energy interactions of protons and neutrons, and apply a technique called the ‘adiabatic projection method’ to reduce the eight-body system to a two-cluster system. We take advantage of the computational efficiency and the more favourable scaling with system size of auxiliary-field Monte Carlo simulations to compute an ab initio effective Hamiltonian for the two clusters. We find promising agreement between lattice results and experimental phase shifts for s-wave and d-wave scattering. The approximately quadratic scaling of computational operations with particle number suggests that it should be possible to compute alpha scattering and capture on carbon and oxygen in the near future. The methods described here can be applied to ultracold atomic few-body systems as well as to hadronic systems using lattice quantum chromodynamics to describe the interactions of

  15. Continuum of the spectra of emitted charged particles

    International Nuclear Information System (INIS)

    The continuous part of nuclear particle spectra situated between direct reactions and compound nuclear reactions is of importance due to its great yield. Because most reactions studied so far have only nucleons in the entrance or exit channel, respectively, the authors have measured charged particle spectra from complex particle induced reactions: deuterons, helions and alphas with bombarding energies up to 40 MeV/nucleon. From spectra measured at both forward and backward angles angle integrated spectra have been deduced which can be compared with the predictions of reaction models. (orig./AH)

  16. Faddeev calculation of 3 alpha and alpha alpha Lambda systems using alpha alpha resonating-group method kernel

    CERN Document Server

    Fujiwara, Y; Kohno, M; Suzuki, Y; Baye, D; Sparenberg, J M

    2004-01-01

    We carry out Faddeev calculations of three-alpha (3 alpha) and two-alpha plus Lambda (alpha alpha Lambda) systems, using two-cluster resonating-group method kernels. The input includes an effective two-nucleon force for the alpha alpha resonating-group method and a new effective Lambda N force for the Lambda alpha interaction. The latter force is a simple two-range Gaussian potential for each spin-singlet and triplet state, generated from the phase-shift behavior of the quark-model hyperon-nucleon interaction, fss2, by using an inversion method based on supersymmetric quantum mechanics. Owing to the exact treatment of the Pauli-forbidden states between the clusters, the present three-cluster Faddeev formalism can describe the mutually related, alpha alpha, 3 alpha and alpha alpha Lambda systems, in terms of a unique set of the baryon-baryon interactions. For the three-range Minnesota force which describes the alpha alpha phase shifts quite accurately, the ground-state and excitation energies of 9Be Lambda are...

  17. Reactor Neutrino Spectra

    CERN Document Server

    Hayes, A C

    2016-01-01

    We present a review of the antineutrino spectra emitted from reactors. Knowledge of these and their associated uncertainties are crucial for neutrino oscillation studies. The spectra used to-date have been determined by either conversion of measured electron spectra to antineutrino spectra or by summing over all of the thousands of transitions that makeup the spectra using modern databases as input. The uncertainties in the subdominant corrections to beta-decay plague both methods, and we provide estimates of these uncertainties. Improving on current knowledge of the antineutrino spectra from reactors will require new experiments. Such experiments would also address the so-called reactor neutrino anomaly and the possible origin of the shoulder observed in the antineutrino spectra measured in recent high-statistics reactor neutrino experiments.

  18. Review of alpha_s determinations

    CERN Document Server

    Pich, Antonio

    2013-01-01

    The present knowledge on the strong coupling is briefly summarized. The most precise determinations of alpha_s, at different energies, are reviewed and compared at the Z mass scale, using the predicted QCD running. The impressive agreement achieved between experimental measurements and theoretical predictions constitutes a beautiful and very significant test of Asymptotic Freedom, establishing QCD as the fundamental theory of the strong interaction. The world average value of the strong coupling is found to be alpha_s(M_Z^2)= 0.1186 \\pm 0.0007.

  19. Alpha spectroscopy for in-situ liquid radioisotope measurements

    International Nuclear Information System (INIS)

    Using calculation and SRIM simulations of alpha particle energy spectroscopy, we show that the initial energies and concentrations of alpha-emitting radioisotopes can be measured in-situ in a liquid environment. We quantify the effect on the alpha spectrum of reducing the thickness of the liquid source in front of the alpha particle detector as well as adding a cover material onto the alpha particle detector surface. In all cases, initial energies and concentrations are recoverable from the alpha particle energy spectra. By reducing the thickness of the liquid source, the contribution to the spectrum for low count rate, low energy radioisotopes can be revealed. However, adding a cover on the detector obscures the contributions of these radioisotopes

  20. Review of alpha_s determinations

    OpenAIRE

    Pich, Antonio

    2013-01-01

    The present knowledge on the strong coupling is briefly summarized. The most precise determinations of alpha_s, at different energies, are reviewed and compared at the Z mass scale, using the predicted QCD running. The impressive agreement achieved between experimental measurements and theoretical predictions constitutes a beautiful and very significant test of Asymptotic Freedom, establishing QCD as the fundamental theory of the strong interaction. The world average value of the strong coupl...

  1. World Summary of $\\alpha_s$ (2015)

    CERN Document Server

    Bethke, Siegfried; Salam, Gavin P

    2015-01-01

    This is a preliminary update of the measurements of α s and the determination of the world average value of α s (M Z 2 ) presented in the 2013/2014 edition of the Review of Particle Properties [1]. A number of studies which became available since late 2013 provide new results for each of the (previously 5, now) 6 subclasses of measurements for which pre-average values of $\\alpha_s (M_Z^2)$ are determined.

  2. Does the alpha cluster structure in light nuclei persist through the fusion process?

    CERN Document Server

    Vadas, J; Schmidt, J; Singh, Varinderjit; Haycraft, C; Hudan, S; deSouza, R T; Baby, L T; Kuvin, S A; Wiedenhover, I

    2015-01-01

    [Background] Despite the importance of light-ion fusion in nucleosynthesis, a limited amount of data exists regarding the de-excitation following fusion for such systems. [Purpose] To explore the characteristics of alpha emission associated with the decay of light fused systems at low excitation energy. [Method] Alpha particles were detected in coincidence with evaporation residues (ER) formed by the fusion of 18O and 12C nuclei. Both alpha particles and ERs were identified on the basis of their energy and time-of-flight. ERs were characterized by their energy spectra and angular distributions while the alpha particles were characterized by their energy spectra, angular distributions, and cross-sections. [Results] While the energy spectra and angular distributions for the alpha particles are well reproduced by statistical model codes, the measured cross-section is substantially underpredicted by the models. Comparison with similar systems reveals that the fundamental quantity for the alpha cross-section is Ec...

  3. Weather Radar Signals with Alpha Stable Distributions

    OpenAIRE

    Lagha, Mohand; Bensebti, Messaoud

    2007-01-01

    This work, treats about a modeling of the weather precipitation echoes detected by a weather pulse Doppler radar. The methods used for the simulation of the Doppler spectrum, and I & Q signals representing the precipitations radar echoes, is based on a macroscopic models, i.e. random processes with assigned spectra. We propose global model, with a power spectrum having a range of statistical distributions ranging between Cauchy and Gauss called alpha-stable model. The results obtained shows t...

  4. Spectra of alkali atoms

    International Nuclear Information System (INIS)

    Emission spectra of alkali atoms has been determined by using spectrometer at the ultraviolet to infra red waves range. The spectra emission can be obtained by absorption spectrophotometric analysis. Comparative evaluations between experimental data and data handbook obtained by spark method were also presented. (author tr.)

  5. Giant Dipole Resonance as a Fingerprint of $\\alpha$ Clustering Configurations in $^{12}$C and $^{16}$O

    CERN Document Server

    He, W B; Cao, X G; Cai, X Z; Zhang, G Q

    2014-01-01

    It is studied how the $\\alpha$ cluster degrees of freedom, such as $\\alpha$ clustering configurations close to the $\\alpha$ decay threshold in $^{12}$C and $^{16}$O, including the linear chain, triangle, square, kite, and tetrahedron, affect nuclear collective vibrations with a microscopic dynamical approach, which can describe properties of nuclear ground states well across the nuclide chart and reproduce the standard giant dipole resonance (GDR) of $^{16}$O quite nicely. It is found that the GDR spectrum is highly fragmented into several apparent peaks due to the $\\alpha$ structure. The different $\\alpha$ cluster configurations in $^{12}$C and $^{16}$O have corresponding characteristic spectra of GDR. The number and centroid energies of peaks in the GDR spectra can be reasonably explained by the geometrical and dynamical symmetries of $\\alpha$ clustering configurations. Therefore, the GDR can be regarded as a very effective probe to diagnose the different $\\alpha$ cluster configurations in light nuclei.

  6. Lyman Alpha Control

    CERN Document Server

    Nielsen, Daniel Stefaniak

    2015-01-01

    This document gives an overview of how to operate the Lyman Alpha Control application written in LabVIEW along with things to watch out for. Overview of the LabVIEW code itself as well as the physical wiring of and connections from/to the NI PCI-6229 DAQ box is also included. The Lyman Alpha Control application is the interface between the ALPHA sequencer and the HighFinesse Wavelength Meter as well as the Lyman Alpha laser setup. The application measures the wavelength of the output light from the Lyman Alpha cavity through the Wavelength Meter. The application can use the Wavelength Meter’s PID capabilities to stabilize the Lyman Alpha laser output as well as switch between up to three frequencies.

  7. New ALPHA-2 magnet

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    On 21 June, members of the ALPHA collaboration celebrated the handover of the first solenoid designed for the ALPHA-2 experiment. The magnet has since been successfully installed and is working well.   Khalid Mansoor, Sumera Yamin and Jeffrey Hangst in front of the new ALPHA-2 solenoid. “This was the first of three identical solenoids that will be installed between now and September, as the rest of the ALPHA-2 device is installed and commissioned,” explains ALPHA spokesperson Jeffrey Hangst. “These magnets are designed to allow us to transfer particles - antiprotons, electrons and positrons - between various parts of the new ALPHA-2 device by controlling the transverse size of the particle bunch that is being transferred.” Sumera Yamin and Khalid Mansoor, two Pakistani scientists from the National Centre for Physics in Islamabad, came to CERN in February specifically to design and manufacture these magnets. “We had the chance to work on act...

  8. Action spectra again?

    Science.gov (United States)

    Coohill, T P

    1991-11-01

    Action spectroscopy has a long history and is of central importance to photobiological studies. Action spectra were among the first assays to point to chlorophyll as the molecule most responsible for plant growth and to DNA as the genetic material. It is useful to construct action spectra early in the investigation of new areas of photobiological research in an attempt to determine the wavelength limits of the radiation region causing the studied response. But due to the severe absorption of ultraviolet (UV) radiation by biological samples, UV action spectra were first limited to small cells (bacteria and fungi). Advances in techniques (e.g. single cell culture) and analysis allowed accurate action spectra to be reported even for mammalian cells. But precise analytical action spectra are often difficult to obtain when large, pigmented, or groups of cells are investigated. Here some action spectra are limited in interpretation and merely supply a wavelength vs effect curve. When polychromatic sources are employed, the interpretation of action spectra is even more complex and formidable. But such polychromatic action spectra can be more directly related to ambient responses. Since precise action spectra usually require the completion of a relatively large number of careful experiments using somewhat sophisticated equipment over a range of at least six wavelengths, they are often not pursued. But they remain central to the elucidation of the effect being studied. The worldwide community has agreed that stratospheric ozone is depleting, with the possibility of a consequent rise in the amount of UV-B (290-320 nm) reaching the earth's surface. It is therefore essential that new action spectra be completed for UV-B effects on a large variety of responses of human, animal, and aquatic plant systems. Combining these action spectra with the known amounts of UV-B reaching the biosphere can give rise to solar UV effectiveness spectra that, in turn, can give rise to estimates

  9. Alpha Shapes and Proteins

    DEFF Research Database (Denmark)

    Winter, Pawel; Sterner, Henrik; Sterner, Peter

    We provide a unified description of (weighted) alpha shapes, beta shapes and the corresponding simplicialcomplexes. We discuss their applicability to various protein-related problems. We also discuss filtrations of alpha shapes and touch upon related persistence issues.We claim that the full...... potential of alpha-shapes and related geometrical constructs in protein-related problems yet remains to be realized and verified. We suggest parallel algorithms for (weighted) alpha shapes, and we argue that future use of filtrations and kinetic variants for larger proteins will need such implementation....

  10. Targeted Alpha Therapy: From Alpha to Omega

    International Nuclear Information System (INIS)

    This review covers the broad spectrum of Targeted Alpha Therapy (TAT) research in Australia; from in vitro and in vivo studies to clinical trials. The principle of tumour anti-vascular alpha therapy (TAVAT) is discussed in terms of its validation by Monte Carlo calculations of vascular models and the potential role of biological dosimetry is examined. Summmary of this review is as follows: 1. The essence of TAT 2. Therapeutic objectives 3. TAVAT and Monte Carlo microdosimetry 4. Biological dosimetry 5. Preclinical studies 6. Clinical trials 7. What next? 8. Obstacles. (author)

  11. Nanodosimetry of radon alpha particles

    International Nuclear Information System (INIS)

    It is currently accepted that energy deposition at the nanometer level (rather than conventional microdosimetry) determines the biological effects of ionizing radiation. Many previously established experimental techniques (e.g., the Rossi proportional counter) or theoretical methods (e.g., simplified calculations using the continuous slowing-down approximation (CSDA)) are inapplicable to the study of nanodosimetry. The peculiarities of the geometry of exposure to radon progeny further complicate the problem. This is because the conditions under which several open-quotes classicalclose quotes models of radiation action are obtained (e.g., the alpha-beta formulation of the Theory of Dual Radiation Action, which is built on microdosimetry) are no longer valid. It thus becomes clear that not only new techniques but new concepts are required to describe the effects of radon alpha particles. In this paper we discuss a number of computational aspects specific to radon nanodosimetry. In particular, we describe the novel concept of open-quotes associated surfaceclose quotes (AS) which is necessary for efficiently converting Monte-Carlo-generated particle tracks to nanodosimetric spectra. The AS is the analog of Lea's associated volume, applied to radiation sources subject to the geometrical restrictions of internal exposure. We systematically analyze factors affecting the nanodosimetry of radon progeny, such as the distance between the radioactive source and the sensitive volume, the size of the sensitive volume, and CSDA versus full Monte-Carlo track generation

  12. Nanodosimetry of radon alpha particles

    Energy Technology Data Exchange (ETDEWEB)

    Zaider, M. [Columbia Univ. New York, NY (United States); Varma, M.N. [U.S. Department of Energy, Washington, DC (United States)

    1992-12-31

    It is currently accepted that energy deposition at the nanometer level (rather than conventional microdosimetry) determines the biological effects of ionizing radiation. Many previously established experimental techniques (e.g., the Rossi proportional counter) or theoretical methods (e.g., simplified calculations using the continuous slowing-down approximation (CSDA)) are inapplicable to the study of nanodosimetry. The peculiarities of the geometry of exposure to radon progeny further complicate the problem. This is because the conditions under which several {open_quotes}classical{close_quotes} models of radiation action are obtained (e.g., the alpha-beta formulation of the Theory of Dual Radiation Action, which is built on microdosimetry) are no longer valid. It thus becomes clear that not only new techniques but new concepts are required to describe the effects of radon alpha particles. In this paper we discuss a number of computational aspects specific to radon nanodosimetry. In particular, we describe the novel concept of {open_quotes}associated surface{close_quotes} (AS) which is necessary for efficiently converting Monte-Carlo-generated particle tracks to nanodosimetric spectra. The AS is the analog of Lea`s associated volume, applied to radiation sources subject to the geometrical restrictions of internal exposure. We systematically analyze factors affecting the nanodosimetry of radon progeny, such as the distance between the radioactive source and the sensitive volume, the size of the sensitive volume, and CSDA versus full Monte-Carlo track generation.

  13. Spectra for commutative algebraists

    OpenAIRE

    Greenlees, J. P. C.

    2006-01-01

    The article is designed to explain to commutative algebraists what spectra (in the sense of algebraic topology) are, why they were originally defined, and how they can be useful for commutative algebra.

  14. Alpha-particle diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Young, K.M.

    1991-01-01

    This paper will focus on the state of development of diagnostics which are expected to provide the information needed for {alpha}- physics studies in the future. Conventional measurement of detailed temporal and spatial profiles of background plasma properties in DT will be essential for such aspects as determining heating effectiveness, shaping of the plasma profiles and effects of MHD, but will not be addressed here. This paper will address (1) the measurement of the neutron source, and hence {alpha}-particle birth profile, (2) measurement of the escaping {alpha}-particles and (3) measurement of the confined {alpha}-particles over their full energy range. There will also be a brief discussion of (4) the concerns about instabilities being generated by {alpha}-particles and the methods necessary for measuring these effects. 51 refs., 10 figs.

  15. Imaging alpha particle detector

    Science.gov (United States)

    Anderson, D.F.

    1980-10-29

    A method and apparatus for detecting and imaging alpha particles sources is described. A dielectric coated high voltage electrode and a tungsten wire grid constitute a diode configuration discharge generator for electrons dislodged from atoms or molecules located in between these electrodes when struck by alpha particles from a source to be quantitatively or qualitatively analyzed. A thin polyester film window allows the alpha particles to pass into the gas enclosure and the combination of the glass electrode, grid and window is light transparent such that the details of the source which is imaged with high resolution and sensitivity by the sparks produced can be observed visually as well. The source can be viewed directly, electronically counted or integrated over time using photographic methods. A significant increase in sensitivity over other alpha particle detectors is observed, and the device has very low sensitivity to gamma or beta emissions which might otherwise appear as noise on the alpha particle signal.

  16. The alpha channeling effect

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, N. J.

    2015-12-10

    Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

  17. Spectral Irradiance Calibration in the Infrared. Part 4; 1.2-35 micrometer Spectra of Six Standard Stars

    Science.gov (United States)

    Cohen, Martin; Witteborn, Fred C.; Walker, Russell, G.; Bregman, Jesse D.; Wooden, Diane H.

    1995-01-01

    Five new absolutely calibrated continuous stellar spectra from 1.2 to 35 microns are presented. The spectra were constructed as far as possible from actual observed spectral fragments taken from the ground, the Kuiper Airborne Observatory (KAO), and the IRAS Low Resolution Spectrometer (LRS). These stars (beta Peg, alpha Boo, beta And, beta Gem, and alpha Hya) augment the author's already created complete absolutely calibrated spectrum for alpha Tau. All these spectra have a common calibration pedigree. The wavelength coverage is ideal for calibration of many existing and proposed ground-based, airborne, and satellite sensors.

  18. Local versus nonlocal $\\alpha\\alpha$ interactions in $3\\alpha$ description of $^{12}$C

    CERN Document Server

    Suzuki, Y; Descouvemont, P; Fujiwara, Y; Matsumura, H; Orabi, M; Theeten, M

    2008-01-01

    Local $\\alpha \\alpha$ potentials fail to describe $^{12}$C as a $3\\alpha$ system. Nonlocal $\\alpha \\alpha$ potentials that renormalize the energy-dependent kernel of the resonating group method allow interpreting simultaneously the ground state and $0^+_2$ resonance of $^{12}$C as $3\\alpha$ states. A comparison with fully microscopic calculations provides a measure of the importance of three-cluster exchanges in those states.

  19. Bremsstrahlung in $\\alpha$ Decay

    CERN Document Server

    Takigawa, N; Hagino, K; Ono, A; Brink, D M

    1999-01-01

    A quantum mechanical analysis of the bremsstrahlung in $\\alpha$ decay of $^{210}$Po is performed in close reference to a semiclassical theory. We clarify the contribution from the tunneling, mixed, outside barrier regions and from the wall of the inner potential well to the final spectral distribution, and discuss their interplay. We also comment on the validity of semiclassical calculations, and the possibility to eliminate the ambiguity in the nuclear potential between the alpha particle and daughter nucleus using the bremsstrahlung spectrum.

  20. Unified model for alpha-decay and alpha-capture

    International Nuclear Information System (INIS)

    A unified model for alpha-decay and alpha-capture is discussed. Simultaneously the half-lives for alpha-transition between ground states as well as ground and excited states and alpha-capture cross-sections by spherical magic or near-magic nuclei are well described in the framework of this model. Using these data the alpha-nucleus potential is obtained. The simple empirical relations for handy evaluation of the half-lives for alpha-transition, which take into account both the angular momentum and parity of alpha-transition, are presented

  1. ALPHA-2: the sequel

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    While many experiments are methodically planning for intense works over the long shutdown, there is one experiment that is already working at full steam: ALPHA-2. Its final components arrived last month and will completely replace the previous ALPHA set-up. Unlike its predecessor, this next generation experiment has been specifically designed to measure the properties of antimatter.   The ALPHA team lower the new superconducting solenoid magnet into place. The ALPHA collaboration is working at full speed to complete the ALPHA-2 set-up for mid-November – this will give them a few weeks of running before the AD shutdown on 17 December. “We really want to get some experience with this device this year so that, if we need to make any changes, we will have time during the long shutdown in which to make them,” says Jeffrey Hangst, ALPHA spokesperson. “Rather than starting the 2014 run in the commissioning stage, we will be up and running from the get go.&...

  2. Alpha Particle Diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Ray, K.

    2009-05-13

    The study of burning plasmas is the next frontier in fusion energy research, and will be a major objective of the U.S. fusion program through U.S. collaboration with our international partners on the ITER Project. For DT magnetic fusion to be useful for energy production, it is essential that the energetic alpha particles produced by the fusion reactions be confined long enough to deposit a significant fraction of their initial ~3.5 MeV energy in the plasma before they are lost. Development of diagnostics to study the behavior of energetic confined alpha particles is a very important if not essential part of burning plasma research. Despite the clear need for these measurements, development of diagnostics to study confined the fast confined alphas to date has proven extremely difficult, and the available techniques remain for the most part unproven and with significant uncertainties. Research under this grant had the goal of developing diagnostics of fast confined alphas, primarily based on measurements of the neutron and ion tails resulting from alpha particle knock-on collisions with the plasma deuterium and tritium fuel ions. One of the strengths of this approach is the ability to measure the alphas in the hot plasma core where the interesting ignition physics will occur.

  3. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  4. Bremsstrahlung during $\\alpha$-decay: quantum multipolar model

    CERN Document Server

    Maydanyuk, Sergei P

    2008-01-01

    In this paper the improved multipolar model of bremsstrahlung accompanied the $\\alpha$-decay is presented. The angular formalism of calculations of the matrix elements, being enough complicated component of the model, is stated in details. A new definition of the angular (differential) probability of the photon emission in the $\\alpha$-decay is proposed where direction of motion of the $\\alpha$-particle outside (with its tunneling inside barrier) is defined on the basis of angular distribution of its spacial wave function. In such approach, the model gives values of the angular probability of the photons emission in absolute scale, without its normalization on experimental data. Effectiveness of the proposed definition and accuracy of the spectra calculations of the bremsstrahlung spectra are analyzed in their comparison with experimental data for the $^{210}{\\rm Po}$, $^{214}{\\rm Po}$, $^{226}{\\rm Ra}$ and $^{244}{\\rm Cm}$ nuclei, and for some other nuclei predictions are performed (in absolute scale). With ...

  5. Resting alpha activity predicts learning ability in alpha neurofeedback

    OpenAIRE

    Wenya eNan; Feng eWan; Mang I eVai; Agostinho eRosa

    2014-01-01

    Individuals differ in their ability to learn how to regulate the alpha activity by neurofeedback. This study aimed to investigate whether the resting alpha activity is related to the learning ability of alpha enhancement in neurofeedback and could be used as a predictor. A total of 25 subjects performed 20 sessions of individualized alpha neurofeedback in order to learn how to enhance activity in the alpha frequency band. The learning ability was assessed by three indices respectively: the tr...

  6. Alpha particles in fusion research

    International Nuclear Information System (INIS)

    This collection of 39 (mostly view graph) presentations addresses various aspects of alpha particle physics in thermonuclear fusion research, including energy balance and alpha particle losses, transport, the influence of alpha particles on plasma stability, helium ash, the transition to and sustainment of a burning fusion plasma, as well as alpha particle diagnostics. Refs, figs and tabs

  7. Spectral Properties From Lyman-alpha to H-alpha For An Essentially Complete Sample of Quasars I: Data

    CERN Document Server

    Shang, Z; Wills, D; Brotherton, M S; Shang, Zhaohui; Wills, Beverley J.; Brotherton, Michael S.

    2007-01-01

    We have obtained quasi-simultaneous ultraviolet-optical spectra for 22 out of 23 quasars in the complete PG-X-ray sample with redshift, z<0.4, and M_B<-23. The spectra cover rest-frame wavelengths from at least Lyman-alpha to H-alpha. Here we provide a detailed description of the data, including careful spectrophotometry and redshift determination. We also present direct measurements of the continua, strong emission lines and features, including Lyman-alpha, SiIV+OIV], CIV, CIII], SiIII], MgII, H-beta, [OIII], He5876+NaI5890,5896, H-alpha, and blended iron emission in the UV and optical. The widths, asymmetries and velocity shifts of profiles of strong emission lines show that CIV and Lyman-alpha are very different from H-beta and H-alpha. This suggests that the motion of the broad line region is related to the ionization structure, but the data appears not agree with the radially stratified ionization structure supported by reverberation mapping studies, and therefore suggest that outflows contribute a...

  8. Measurements of energetic confined alphas and tritons on TFTR

    International Nuclear Information System (INIS)

    In a collaboration involving General Atomics, the A. F. Ioffe Physical-Technical Institute, and the Princeton Plasma Physics Laboratory, the energy distribution of the fast-confined alpha particles in DT experiments on TFIR is being measured by active neutral particle analysis using the ablation cloud surrounding an injected impurity pellet as the neutralizer. Recent papers reported the first measurements of the energy distribution fast confined alpha particles and examined the influence of magnetic field ripple and sawtooth oscillations on the behavior of the alpha energy spectra and radial density distributions. This paper focuses on alpha and triton measurements in the core of quiescent TFTR discharges where the expected classical slowing down and pitch angle scattering effects are not complicated by stochastic ripple diffusion and sawtooth activity

  9. Stellar parametrization from Gaia RVS spectra

    CERN Document Server

    Recio-Blanco, A; Prieto, C Allende; Fustes, D; Manteiga, M; Arcay, B; Bijaoui, A; Dafonte, C; Ordenovic, C; Blanco, D Ordoñez

    2016-01-01

    Among the myriad of data collected by the ESA Gaia satellite, about 150 million spectra will be delivered by the Radial Velocity Spectrometer (RVS) for stars as faint as G_RVS~16. A specific stellar parametrization will be performed for most of these RVS spectra. Some individual chemical abundances will also be estimated for the brightest targets. We describe the different parametrization codes that have been specifically developed or adapted for RVS spectra within the GSP-spec working group of the analysis consortium. The tested codes are based on optimization (FERRE and GAUGUIN), projection (MATISSE) or pattern recognition methods (Artificial Neural Networks). We present and discuss their expected performances in the recovered stellar atmospheric parameters (Teff, log(g), [M/H]) for B- to K- type stars. The performances for the determinations of [alpha/Fe] ratios are also presented for cool stars. For all the considered stellar types, stars brighter than G_RVS~12.5 will be very efficiently parametrized by t...

  10. Limits on variations of the fine-structure constant with gravitational potential from white-dwarf spectra

    CERN Document Server

    Berengut, J C; Ong, A; Webb, J K; Barrow, John D; Barstow, M A; Preval, S P; Holberg, J B

    2013-01-01

    We propose a new probe of the variation of the fine structure constant, alpha, in a strong gravitational field using metal lines in the spectra of white dwarf stars. Comparison of laboratory spectra with far-UV astronomical spectra from the white dwarf star G191-B2B recorded by the Hubble Space Telescope Imaging Spectrograph gives limits on the fractional variation of alpha of (Delta alpha/alpha)=(4.2 +- 1.6)x10^(-5) and (-6.1 +- 5.8)x10^(-5) from Fe V and Ni V spectra, respectively, at a dimensionless gravitational potential relative to Earth of (Delta phi) ~ 5x10^(-5). With better determinations of the laboratory wavelengths of the lines employed these results could be improved by up to two orders of magnitude.

  11. Alpha radiation measurement - Recommendations dossier for measurements optimization

    International Nuclear Information System (INIS)

    Used in the medical domain, in the military industry or in the electronuclear industry, the alpha radiation, by its detection and measurement, is of prime importance for the environmental control, the follow up of any industrial technical operation or the measurement of the health impact of radioactivity. This book gathers the basic knowledge, both practical and theoretical, and the necessary recommendations that any operator, technician or engineer would need to know for the use of alpha spectroscopy as a quantitative and qualitative method of analysis. It supplies information in the domains of: - sources preparation for alpha spectroscopy measurement; - measurements implementation for each technique: proportional counter, semiconductor alpha spectroscopy, grid chamber and liquid scintillation; - results processing and display; - quality assurance. It makes a synthesis of the know-how of laboratories in the fabrication of thin sources by supplying simple but important rules as well as information allowing to deal with the physical and chemical limits of thin sources. It lists the techniques relative to alpha particles detection and describes for each of them their sensitivity, advantages and drawbacks, and field of use. It introduces in the simplest as possible manner the mathematical tools needed for spectra deconvolution with some practical examples allowing to illustrate some complex situations encountered. It supplies to the user the theoretical and practical background necessary for the production of reliable and valid results. Finally, it includes and discusses the recent considerations about the calculation of decision threshold and detection limits. Content: 1 - reference documents: scientific and technical documents, standards, nuclear data; 2 - natural and artificial alpha radioactivity: discovery of alpha radiation, natural alpha radioactivity, artificial alpha radioactivity (medical, industrial exposure), dating method using nuclear phenomena; 3

  12. ALPHA MIS: Reference manual

    Energy Technology Data Exchange (ETDEWEB)

    Lovin, J.K.; Haese, R.L.; Heatherly, R.D.; Hughes, S.E.; Ishee, J.S.; Pratt, S.M.; Smith, D.W.

    1992-02-01

    ALPHA is a powerful and versatile management information system (MIS) initiated and sponsored and by the Finance and Business Management Division of Oak Ridge National Laboratory, who maintain and develop it in concert with the Business Systems Division for its Information Center. A general-purpose MIS, ALPHA allows users to access System 1022 and System 1032 databases to obtain and manage information. From a personal computer or a data terminal, Energy Systems employees can use ALPHA to control their own report reprocessing. Using four general commands (Database, Select, Sort, and Report) they can (1) choose a mainframe database, (2) define subsets within it, (3) sequentially order a subset by one or more variables, and (4) generate a report with their own or a canned format.

  13. H$_{\\alpha}$ line as an indicator of envelope presence around the Cepheid Polaris Aa ($\\alpha~ UMi$)

    CERN Document Server

    Usenko, I A; Klochkova, V G; Tavolzhanskaya, N S

    2015-01-01

    We present the results of the radial velocity ($RV$) measurements of metallic lines as well as H$_{\\alpha}$ (H$_{\\beta}$) obtained in 55 high-resolution spectra of the Cepheid $\\alpha$ UMi (Polaris Aa) in 1994-2010. While the $RV$ amplitudes of these lines are roughly equal, their mean $RV$ begin to differ essentially with growth of the Polaris Aa pulsational activity. This difference is accompanied by the H$_{\\alpha}$ line core asymmetries on the red side mainly (so-called knife-like profiles) and reaches 8-12 km/s in 2003 with a subsequent decrease to 1.5-2 km/s. We interpret a so unusual behaviour of the H$_{\\alpha}$ line core as dynamical changes in the envelope around Polaris Aa.

  14. Analysis of radiation risk from alpha particle component of soalr particle events

    Science.gov (United States)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

    1994-01-01

    The Solar Particle Events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and Linear Energy Transfer (LET) spectra in shielding are discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

  15. Analysis of radiation risk from alpha particle component of solar particle events

    Science.gov (United States)

    Cucinotta, F. A.; Townsend, L. W.; Wilson, J. W.; Golightly, M. J.; Weyland, M.

    1994-01-01

    The solar particle events (SPE) will contain a primary alpha particle component, representing a possible increase in the potential risk to astronauts during an SPE over the often studied proton component. We discuss the physical interactions of alpha particles important in describing the transport of these particles through spacecraft and body shielding. Models of light ion reactions are presented and their effects on energy and linear energy transfer (LET) spectra in shielding discussed. We present predictions of particle spectra, dose, and dose equivalent in organs of interest for SPE spectra typical of those occurring in recent solar cycles. The large events of solar cycle 19 are found to have substantial increase in biological risk from alpha particles, including a large increase in secondary neutron production from alpha particle breakup.

  16. Giant Lyman-Alpha Nebulae in the Illustris Simulation

    CERN Document Server

    Gronke, Max

    2016-01-01

    Several `giant' Lyman-$\\alpha$ (Ly$\\alpha$) nebulae with extent $\\gtrsim 300\\,$kpc and observed Ly$\\alpha$ luminosity of $\\gtrsim 10^{44}\\,{\\rm erg}\\,{\\rm s}^{-1}\\,{\\rm cm}^{-2}\\,{\\rm arcsec}^{-2}$ have recently been detected, and it has been speculated that their presence hints at a substantial cold gas reservoir in small cool clumps not resolved in modern hydro-dynamical simulations. We use the Illustris simulation to predict the Ly$\\alpha$ emission emerging from large halos ($M > 10^{11.5}M_{\\odot}$) at $z\\sim 2$ and thus test this model. We consider both AGN and star driven ionization, and compared the simulated surface brightness maps, profiles and Ly$\\alpha$ spectra to a model where most gas is clumped below the simulation resolution scale. We find that while the cold clumps boost the Ly$\\alpha$ luminosity especially in the outer regions of the halo -- as expected by previous work -- with Illustris no additional clumping is necessary to explain the extents and luminosities of the `giant Ly$\\alpha$ nebul...

  17. Alpha and evangelical conversion

    OpenAIRE

    Stout, A.; Dein, S.

    2013-01-01

    A semi-structured interview study was conducted among 11 ‘Born Again’ Christians eliciting their conversion narratives. Informants emphasised the importance of embodying the Holy Spirit and developing a personal relationship with Christ in the process of conversion. The Alpha Course played an important role in this process.

  18. Alpha-mannosidosis

    DEFF Research Database (Denmark)

    Borgwardt, Line; Stensland, Hilde Monica Frostad Riise; Olsen, Klaus Juul;

    2015-01-01

    the three subgroups of genotype/subcellular localisation and the clinical and biochemical data were done to investigate the potential relationship between genotype and phenotype in alpha-mannosidosis. Statistical analyses were performed using the SPSS software. Analyses of covariance were performed to...

  19. Deconvolution of Positrons' Lifetime spectra

    International Nuclear Information System (INIS)

    In this paper, we explain the iterative method previously develop for the deconvolution of Doppler broadening spectra using the mathematical optimization theory. Also, we start the adaptation and application of this method to the deconvolution of positrons' lifetime annihilation spectra

  20. The $\\alpha_S$ Dependence of Parton Distributions

    OpenAIRE

    Martin, A. D.; Stirling, W. J.; Roberts, R G

    1995-01-01

    We perform next-to-leading order global analyses of deep inelastic and related data for different fixed values of $\\alpha_S (M_Z^2)$. We present sets of parton distributions for six values of $\\alpha_S$ in the range 0.105 to 0.130. We display the $(x, Q^2)$ domains with the largest parton uncertainty and we discuss how forthcoming data may be able to improve the determination of the parton densities.

  1. The Lyman Alpha Reference Sample: V. The impact of neutral ISM kinematics and geometry on Lyman Alpha escape

    CERN Document Server

    Rivera-Thorsen, Thøger E; Östlin, Göran; Duval, Florent; Orlitová, Ivana; Verhamme, Anne; Mas-Hesse, J Miguel; Schaerer, Daniel; Cannon, John M; Otí-Floranes, Héctor; Sandberg, Andreas; Guaita, Lucia; Adamo, Angela; Atek, Hakim; Herentz, E Christian; Kunth, Daniel; Laursen, Peter; Melinder, Jens

    2015-01-01

    We present high-resolution far-UV spectroscopy of the 14 galaxies of the Lyman Alpha Reference Sample; a sample of strongly star-forming galaxies at low redshifts ($0.028 < z < 0.18$). We compare the derived properties to global properties derived from multi band imaging and 21 cm HI interferometry and single dish observations, as well as archival optical SDSS spectra. Besides the Lyman $\\alpha$ line, the spectra contain a number of metal absorption features allowing us to probe the kinematics of the neutral ISM and evaluate the optical depth and and covering fraction of the neutral medium as a function of line-of-sight velocity. Furthermore, we show how this, in combination with precise determination of systemic velocity and good Ly$\\alpha$ spectra, can be used to distinguish a model in which separate clumps together fully cover the background source, from the "picket fence" model named by Heckman et al. (2011). We find that no one single effect dominates in governing Ly$\\alpha$ radiative transfer and ...

  2. Genetics Home Reference: alpha thalassemia

    Science.gov (United States)

    ... for Disease Control and Prevention Centre for Genetics Education (Australia) Cooley's Anemia Foundation: Fact sheet about alpha thalassemia Disease InfoSearch: Alpha-Thalassemia Genomics Education Programme (UK) Information Center for Sickle Cell and ...

  3. Calculation of Vibrational Energy-Spectra of α-Helical Protein Molecules and Its Properties

    Institute of Scientific and Technical Information of China (English)

    PANG XiaoFeng; CHEN XiangRong

    2002-01-01

    The quantum vibrational energy-spectra of amide-Is in alpha-protein molecules are calculated by using the discretely nonlinear Schrodinger equation and physical parameters appropriate to the systems on the basis of theory of bio-energy transport. The numerical results for the energy-spectra are basically consistent with the experimental values obtained by the infrared absorption and Raman scattering and emission-spectra of infrared lights of person's hand-fingers. Utilizing the energy-spectra we explain the laser-Raman spectrum from metabolically active E. Coli. and give some features of the infrared absorption of the protein molecules.

  4. $\\alpha$-minimal Banach spaces

    CERN Document Server

    Rosendal, Christian

    2011-01-01

    A Banach space with a Schauder basis is said to be $\\alpha$-minimal for some countable ordinal $\\alpha$ if, for any two block subspaces, the Bourgain embeddability index of one into the other is at least $\\alpha$. We prove a dichotomy that characterises when a Banach space has an $\\alpha$-minimal subspace, which contributes to the ongoing project, initiated by W. T. Gowers, of classifying separable Banach spaces by identifying characteristic subspaces.

  5. 3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies

    CERN Document Server

    Verhamme, A; Maselli, A; Verhamme, Anne; Schaerer, Daniel; Maselli, Antonella

    2006-01-01

    Using a Monte Carlo technique, we have developed a 3D lyman-alpha radiation transfer code allowing for prescribed arbitrary hydrogen density, ionisation, temperature structures, and dust distribution, and arbitrary velocity fields and UV photon sources. We have examined the lyman-alpha line profiles predicted for several simple geometrical configurations and their dependence on the main input parameters. Overall, we find line profiles reaching from doubly peaked symmetric emission to symmetric Voigt (absorption) in static configurations with increasing dust content, and asymmetric red-(blue-) shifted emission lines with a blue (red) counterpart ranging from absorption to emission (with increasing line/continuum strength) in expanding (infalling) media. The following results are of interest for the interpretation of lya profiles from galaxies. 1/ Standard lya absorption line fitting of global spectra of galaxies may lead to an underestimate of the true hydrogen column density in certain geometrical conditions....

  6. Monomeric C-phycocyanin at room temperature and 77 K. Resolution of the absorption and fluorescence spectra of the individual chromophores and the energy-transfer rate constants

    Energy Technology Data Exchange (ETDEWEB)

    Debreczeny, M.P.; Sauer, K. (Lawrence Berkeley Lab., CA (United States) Univ. of California, Berkeley, CA (United States)); Zhou, J.; Bryant, D.A. (Pennsylvania State Univ., University Park, PA (United States))

    1993-09-23

    At both room temperature (RT) and 77 K, the absorption and fluorescence spectra of the three individual chromophore types ([alpha][sub 84], [beta][sub 84], and [beta][sub 155]) found in monomeric C-phycocyanin ([alpha][sup PC][beta][sup PC]), isolated from the cyanobacterium Synechococcus sp. PCC 7002, were resolved along with the rates of energy transfer between the chromophores. The cpcB/C155S mutant, whose PC is missing the [beta][sub 155] chromophore, was useful in effecting this resolution. At RT, the single broad peak in the visible region of the absorption spectrum of ([alpha][sup PC][beta][sup PC]) was resolved into its three-component spectra by comparing the steady-state absorption spectra of the isolated wild-type [alpha] subunit of PC ([alpha][sup PC]) (containing only the [alpha][sub 84] chromophore) with those of the monomeric PCs isolated from the mutant strain ([alpha][sup PC][beta]*) and the wild-type strain ([alpha][sup PC][beta][sup PC]). At 77 K, the visible region of the absorption spectrum of ([alpha][sup PC][beta][sup PC]) splits into two peaks. This partial resolution at 77 K of the chromophore spectra of ([alpha][sup PC][beta][sup PC]) when compared with the 77 K absorption spectra of [alpha][sup PC], [beta][sup PC], and ([alpha][sup PC][beta]*) provided a confirmation of our RT assignments of the chromophore absorption spectra. 38 refs., 9 figs., 6 tabs.

  7. Sequencing BPS Spectra

    CERN Document Server

    Gukov, Sergei; Saberi, Ingmar; Stosic, Marko; Sulkowski, Piotr

    2015-01-01

    This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincar\\'e polynomials in numerous examples. Among these structural properties is a novel "sliding" property, which can be explained by using (refined) modular $S$-matrix. This leads to the identifi...

  8. Resting alpha activity predicts learning ability in alpha neurofeedback

    Directory of Open Access Journals (Sweden)

    Wenya eNan

    2014-07-01

    Full Text Available Individuals differ in their ability to learn how to regulate the alpha activity by neurofeedback. This study aimed to investigate whether the resting alpha activity is related to the learning ability of alpha enhancement in neurofeedback and could be used as a predictor. A total of 25 subjects performed 20 sessions of individualized alpha neurofeedback in order to learn how to enhance activity in the alpha frequency band. The learning ability was assessed by three indices respectively: the training parameter changes between two periods, within a short period and across the whole training time. It was found that the resting alpha amplitude measured before training had significant positive correlations with all learning indices and could be used as a predictor for the learning ability prediction. This finding would help the researchers in not only predicting the training efficacy in individuals but also gaining further insight into the mechanisms of alpha neurofeedback.

  9. Spectral Irradiance Calibration in the Infrared. Part 4; 1.2 - 35 microns Spectra of Six Standard Stars

    Science.gov (United States)

    Cohen, Martin; Witteborn, Fred C.; Walker, Russell G.; Bregman, Jesse D.; Wooden, Diane H.

    1995-01-01

    We present five new absolutely calibrated continuous stellar spectra from 1.2 to 35 microns, constructed as far as possible from actual observed spectral fragments taken from the ground, the Kuiper Airborne Observatory (KAO), and the IRAS Low Resolution Spectrometer (LRS). These stars- beta Peg, alpha Boo, beta And, beta Gem, and alpha Hya-augment our already created complete absolutely calibrated spectrum for alpha Tau. All these spectra have a common calibration pedigree. The wavelength coverage is ideal for calibration of many existing and proposed ground-based, airborne, and satellite sensors.

  10. Alpha scintillation radon counting

    International Nuclear Information System (INIS)

    Radon counting chambers which utilize the alpha-scintillation properties of silver activated zinc sulfide are simple to construct, have a high efficiency, and, with proper design, may be relatively insensitive to variations in the pressure or purity of the counter filling. Chambers which were constructed from glass, metal, or plastic in a wide variety of shapes and sizes were evaluated for the accuracy and the precision of the radon counting. The principles affecting the alpha-scintillation radon counting chamber design and an analytic system suitable for a large scale study of the 222Rn and 226Ra content of either air or other environmental samples are described. Particular note is taken of those factors which affect the accuracy and the precision of the method for monitoring radioactivity around uranium mines

  11. Rossi Alpha Method

    International Nuclear Information System (INIS)

    The Rossi Alpha Method has proved to be valuable for the determination of prompt neutron lifetimes in fissile assemblies having known reproduction numbers at or near delayed critical. This workshop report emphasizes the pioneering applications of the method by Dr. John D. Orndoff to fast-neutron critical assemblies at Los Alamos. The value of the method appears to disappear for subcritical systems where the Rossi-α is no longer an α-eigenvalue

  12. Combining Alphas via Bounded Regression

    Directory of Open Access Journals (Sweden)

    Zura Kakushadze

    2015-11-01

    Full Text Available We give an explicit algorithm and source code for combining alpha streams via bounded regression. In practical applications, typically, there is insufficient history to compute a sample covariance matrix (SCM for a large number of alphas. To compute alpha allocation weights, one then resorts to (weighted regression over SCM principal components. Regression often produces alpha weights with insufficient diversification and/or skewed distribution against, e.g., turnover. This can be rectified by imposing bounds on alpha weights within the regression procedure. Bounded regression can also be applied to stock and other asset portfolio construction. We discuss illustrative examples.

  13. Calculating fusion neutron energy spectra from arbitrary reactant distributions

    Science.gov (United States)

    Eriksson, J.; Conroy, S.; Andersson Sundén, E.; Hellesen, C.

    2016-02-01

    The Directional Relativistic Spectrum Simulator (DRESS) code can perform Monte-Carlo calculations of reaction product spectra from arbitrary reactant distributions, using fully relativistic kinematics. The code is set up to calculate energy spectra from neutrons and alpha particles produced in the D(d, n)3He and T(d, n)4He fusion reactions, but any two-body reaction can be simulated by including the corresponding cross section. The code has been thoroughly tested. The kinematics calculations have been benchmarked against the kinematics module of the ROOT Data Analysis Framework. Calculated neutron energy spectra have been validated against tabulated fusion reactivities and against an exact analytical expression for the thermonuclear fusion neutron spectrum, with good agreement. The DRESS code will be used as the core of a detailed synthetic diagnostic framework for neutron measurements at the JET and MAST tokamaks.

  14. Gamma power is phase-locked to posterior alpha activity.

    Directory of Open Access Journals (Sweden)

    Daria Osipova

    Full Text Available Neuronal oscillations in various frequency bands have been reported in numerous studies in both humans and animals. While it is obvious that these oscillations play an important role in cognitive processing, it remains unclear how oscillations in various frequency bands interact. In this study we have investigated phase to power locking in MEG activity of healthy human subjects at rest with their eyes closed. To examine cross-frequency coupling, we have computed coherence between the time course of the power in a given frequency band and the signal itself within every channel. The time-course of the power was calculated using a sliding tapered time window followed by a Fourier transform. Our findings show that high-frequency gamma power (30-70 Hz is phase-locked to alpha oscillations (8-13 Hz in the ongoing MEG signals. The topography of the coupling was similar to the topography of the alpha power and was strongest over occipital areas. Interestingly, gamma activity per se was not evident in the power spectra and only became detectable when studied in relation to the alpha phase. Intracranial data from an epileptic subject confirmed these findings albeit there was slowing in both the alpha and gamma band. A tentative explanation for this phenomenon is that the visual system is inhibited during most of the alpha cycle whereas a burst of gamma activity at a specific alpha phase (e.g. at troughs reflects a window of excitability.

  15. Alpha-globin loci in homozygous beta-thalassemia intermedia.

    Science.gov (United States)

    Triadou, P; Lapoumeroulie, C; Girot, R; Labie, D

    1983-01-01

    Homozygous beta-thalassemia intermediate (TI) differs from thalassemia major (TM) in being less severe clinically. Associated alpha-thalassemia could account for the TI phenotype by reducing the alpha/non-alpha chain imbalance. We have analyzed the alpha loci of 9 TI and 11 TM patients by restriction endonuclease mapping. All the TM and 7 of the TI patients have the normal complement of four alpha-globin genes (alpha alpha/alpha alpha). One TI patient has three alpha-globin genes (alpha alpha/-alpha), and another TI patient has five alpha genes (alpha alpha/alpha alpha alpha). PMID:6305827

  16. Spectra of hot stars

    Science.gov (United States)

    Hillier, D. John

    2015-08-01

    Non-LTE modeling is essential for interpreting the spectra of O stars and their decendents, and much progress has been made. The major uncertainty associated with analyzing photospheric spectra of O stars arises from issues related to microturbulence and macroturbulence. Many supergiants, for example, have microturbulent velocities that approach the sound speed, while macroturbulent velocities are often several times the sound speed. The cause of this turbulence is unknown, but may be related to pulsation, an underlying convection zone associated with the Fe opacity bump, or feedback from the stellar wind. Determining accurate abundances in O stars is hampered by the lack of lines belonging to low-z elements. Many species only have a few observable lines, and some of these are subject to complex non-LTE effects. A characteristic of massive stars is the existence of a stellar wind which is driven by radiation pressure. Radiation driving is inherently unstable, and this leads to winds with an inhomogeneous structure. Major issues that are still unresolved include: How are winds driven through the sonic point? What is the nature of the inhomogeneities, and how do the properties of these inhomogeneities change with density and velocity? How important is spatial porosity, and porosity in velocity space? What is the structure of the shocks, and in what stars do the shocks fail to cool? With Wolf-Rayet (W-R) stars the major uncertainty arises because the classic spectroscopic radius (i.e., the location where τ = 2/3) often refers to a location in the wind — not necessarily the stellar radius associated with stellar evolution models. Derived radii are typically several times those predicted by stellar evolution calculations, although for strong-lined W-R stars it is possible to construct models that are consistent with evolution calculations. The driving of the winds in these stars is strongly coupled to the closeness of the stars to the Eddington limit and to their

  17. Non-Voigt Lyman-$\\alpha$ absorption line profiles

    CERN Document Server

    Outram, P J; Theuns, T

    1999-01-01

    Recent numerical simulations have lead to a paradigm shift in our understanding of the intergalactic medium, and the loss of a physical justification for Voigt profile fitting of the Lyman-alpha forest. Many individual lines seen in simulated spectra have significant departures from the Voigt profile, yet could be well fitted by a blend of two or more such lines. We discuss the expected effect on the line profiles due to ongoing gravitational structure formation and Hubble expansion. We develop a method to detect departures from Voigt profiles of the absorption lines in a statistical way and apply this method to simulated Lyman-alpha forest spectra, confirming that the profiles seen do statistically differ from Voigt profiles.

  18. Comparison of (α,n) thick-target neutron yields and spectra from ORIGEN-S and SOURCES

    International Nuclear Information System (INIS)

    Both ORIGEN-S and SOURCES generate thick-target neutron yields and energy spectra from (α, n) reactions in homogeneous material containing alpha-emitting and (α,n) target elements by simulating reaction physics, using alpha-emission energy spectra, elemental stopping cross sections, (α, n) target elements by simulating reaction physics, using alpha-emission energy spectra, elemental stopping cross sections, (α, n) cross sections for target nuclei, and branching fractions to product-nuclide energy levels. This methodology results in accurate yield and spectra. ORIGEN-S has two options for calculating yields and spectra. The UO2 option (default) estimates yields and spectra assuming the input alpha emitters to be infinitely dilute in UO2. The borosilicate-glass option estimates yields from the total input material composition and generates spectra purportedly representative of spectra generated by 238Pu, 241Am, 242Cm, and 244Cm infinitely dilute in borosilicate glass, even if none of these four alpha emitters are present in the input material composition. Because yields from the borosilicate-glass option in ORIGEN-S are based on entire input material composition and are reasonably accurate, the same is often assumed to be true for spectra. The input/output functionality of the borosilicate-glass option, along with ambiguity in ORIGEN-S documentation, gives the incorrect impression that spectra representative of input compositions are generated. This impression is reinforced by wide usage of the SCALE code system and its ORIGEN-S module and their sponsorship by the US Nuclear Regulatory Commission

  19. Structure and function of carboxypeptidase A alpha in supercooled water.

    OpenAIRE

    Thompson, J. S.; Gehring, H; Vallee, B L

    1980-01-01

    The spectral and enzymatic characteristics of chromophoric derivatives of carboxypeptidase A alpha (EC 3.4.17.1) have been examined at subzero temperatures in supercooled water-in-oil emulsions. Substrate and temperature dependencies of enzyme kinetics indicated the existence of a solution-like enzyme phase that greatly extends the temperature range (greater than 60 degrees C) over which the activity of this enzyme can be measured. The emulsion spectra were virtually identical to those of sol...

  20. Non-Voigt Lyman-alpha absorption line profiles

    OpenAIRE

    Outram, P. J.; Carswell, R.F.; Theuns, T.

    1999-01-01

    Recent numerical simulations have lead to a paradigm shift in our understanding of the intergalactic medium, and the loss of a physical justification for Voigt profile fitting of the Lyman-alpha forest. Many individual lines seen in simulated spectra have significant departures from the Voigt profile, yet could be well fitted by a blend of two or more such lines. We discuss the expected effect on the line profiles due to ongoing gravitational structure formation and Hubble expansion. We devel...

  1. Examination of returned Surveyor 3 camera visor for alpha radioactivity

    Science.gov (United States)

    Economou, T. E.; Turkevich, A. L.

    1972-01-01

    The TV camera visor was placed in a vacuum chamber and examined for alpha radioactivity using an alpha-scattering instrument, and plates covered with the same paint and made at the same time as the visor were used as a control. The spectra of visor and plates are very similar, and it is concluded that the gross activity on the visor is due entirely to the activity of the paint. The data were used to obtain the amount of Po-210 activity on the lunar surface. It is felt that the lack of detected alpha radioactivity does not indicate a lack of activity on the moon, since dust layers were knocked off the visor.

  2. Measurement of differential (n,x{alpha}) cross section using 4{pi} gridded ionization chamber

    Energy Technology Data Exchange (ETDEWEB)

    Sanami, Toshiya; Baba, Mamoru; Matsuyama, Shigeo; Kiyosumi, Takehide; Nauchi, Yasushi; Saito, Keiichiro; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering; Kawano, Toshihiko

    1997-03-01

    We carried out the measurements of high resolution {alpha} emission spectra of {sup 58}Ni and {sup nat}Ni between 4.5 and 6.5 MeV, and {sup 12}C(n,x{alpha}) cross section using a 4{pi} gridded ionization chamber. In Ni measurement, overall energy resolution was improved to around 200 keV by optimizing a sample thickness and a neutron source width. Measured alpha spectra showed separate peaks corresponding to the ground and low-lying excited states of the residual nucleus ({sup 55}Fe). These results were compared with another direct measurement and statistical model calculations. In {sup 12}C measurement, GIC was applied for (n,x{alpha}) reactions of light nuclei. This application is difficult to (n,x{alpha}) cross sections of light nuclei, because of the influences of large recoil energy and multi-body break-up. We developed new methods which eliminate the effects of recoil nuclei and multi-body break-up and applied them to {sup 12}C(n,x{alpha}) reaction at En=14.1 MeV. In our experiment, the {sup 12}C(n,{alpha}{sub 0}){sup 9}Be angular differential cross section and {sup 12}C(n,n`3{alpha}) cross section were obtained. (author)

  3. Unfolding domains of recombinant fusion alpha alpha-tropomyosin.

    OpenAIRE

    Ishii, Y; Hitchcock-DeGregori, S.; Mabuchi, K; Lehrer, S S

    1992-01-01

    The thermal unfolding of the coiled-coil alpha-helix of recombinant alpha alpha-tropomyosin from rat striated muscle containing an additional 80-residue peptide of influenza virus NS1 protein at the N-terminus (fusion-tropomyosin) was studied with circular dichroism and fluorescence techniques. Fusion-tropomyosin unfolded in four cooperative transitions: (1) a pretransition starting at 35 degrees C involving the middle of the molecule; (2) a major transition at 46 degrees C involving no more ...

  4. The AMBRE Project: Parameterisation of FGK-type stars from the ESO:HARPS archived spectra

    CERN Document Server

    De Pascale, Marco; de Laverny, Patrick; Recio-Blanco, Alejandra; Hill, Vanessa; Bijaoui, Albert

    2014-01-01

    The AMBRE project is a collaboration between the European Southern Observatory (ESO) and the Observatoire de la Cote d'Azur (OCA). It has been established to determine the stellar atmospheric parameters (effective temperature, surface gravity, global metallicities and abundance of alpha-elements over iron) of the archived spectra of four ESO spectrographs. The analysis of the ESO:HARPS archived spectra is presented. The sample being analysed (AMBRE:HARPS) covers the period from 2003 to 2010 and is comprised of 126688 scientific spectra corresponding to 17218 different stars. For the analysis of the spectral sample, the automated pipeline developed for the analysis of the AMBRE:FEROS archived spectra has been adapted to the characteristics of the HARPS spectra. Within the pipeline, the stellar parameters are determined by the MATISSE algorithm, developed at OCA for the analysis of large samples of stellar spectra in the framework of galactic archaeology. In the present application, MATISSE uses the AMBRE grid ...

  5. Bi209 alpha activity

    International Nuclear Information System (INIS)

    The study for measuring Bi209 alpha activity is presented. Ilford L4 nuclear emulsion pellicles loaded with bismuth citrate to obtain a load of 100 mg/cm3 of dry emulsion, were prepared. Other pellicles were prepared with the same. Ilford L4 gel to estimate the background radiation. To observe 'fading' effect, pellicles loaded with bismuth were submitted to neutrons of high energy, aiming to record recoil proton tracks. The pellicles were confined in nitrogen atmosphere at temperature lower than -100C. The Bi209 experimental half-life was obtained and compared with the estimated theoretical data. (M.C.K.)

  6. Cosmic density field reconstruction from Ly-alpha forest data

    CERN Document Server

    Gallerani, Simona; Ferrara, Andrea

    2010-01-01

    We present a novel, fast method to recover the density field through the statistics of the transmitted flux in high redshift quasar absorption spectra. The proposed technique requires the computation of the probability distribution function of the transmitted flux (P_F) in the Ly-alpha forest region and, as a sole assumption, the knowledge of the probability distribution function of the matter density field (P_Delta). We show that the probability density conservation of the flux and matter density unveils a flux-density (F-Delta) relation which can be used to invert the Ly-alpha forest without any assumption on the physical properties of the intergalactic medium. We test our inversion method at z=3 through the following steps: [i] simulation of a sample of synthetic spectra for which P_Delta is known; [ii] computation of P_F; [iii] inversion of the Ly-alpha forest through the F-Delta relation. Our technique, when applied to only 10 observed spectra characterized by a signal-to noise ratio S/N >= 100 provides ...

  7. Background canceling surface alpha detector

    International Nuclear Information System (INIS)

    A background canceling long range alpha detector which is capable of providing output proportional to both the alpha radiation emitted from a surface and to radioactive gas emanating from the surface. The detector operates by using an electrical field between first and second signal planes, an enclosure and the surface or substance to be monitored for alpha radiation. The first and second signal planes are maintained at the same voltage with respect to the electrically conductive enclosure, reducing leakage currents. In the presence of alpha radiation and radioactive gas decay, the signal from the first signal plane is proportional to both the surface alpha radiation and to the airborne radioactive gas, while the signal from the second signal plane is proportional only to the airborne radioactive gas. The difference between these two signals is proportional to the surface alpha radiation alone. 5 figs

  8. Alpha activity measurement with lsc

    International Nuclear Information System (INIS)

    Recently, we showed that the alpha activity in liquid samples can be measured using a liquid scintillation analyzer without alpha/beta discrimination capability. The purpose of this work was to evaluate the performances of the method and to optimize the procedure of the sample preparation. A series of tests was performed to validate the procedure of alpha emitting radionuclides extraction in aqueous samples with Actinide Resin, especially regarding to the contact time required to extract all alpha nuclides. The main conclusions were that a minimum 18 hours stirring time is needed to achieve a percent recovery of the alpha nuclides grater than 90% and that the counting efficiency of alphas measurements with LSC is nearly 100%. (authors)

  9. Charge Exchange Spectra of Hydrogenic and He-like Iron

    CERN Document Server

    Wargelin, B J; Neill, P A; Olson, R E; Scofield, J H

    2005-01-01

    We present H-like Fe XXVI and He-like Fe XXV charge-exchange spectra resulting from collisions of highly charged iron with N2 gas at an energy of 10 eV/amu in an electron beam ion trap. Although individual high-n emission lines are not resolved in our measurements, we observe that the most likely level for Fe25+ --> Fe24+ electron capture is n~9, in line with expectations, while the most likely value for Fe26+ --> Fe25+ charge exchange is significantly higher. In the Fe XXV spectrum, the K-alpha emission feature dominates, whether produced via charge exchange or collisional excitation. The K-alpha centroid is lower in energy for the former case than the latter (6666 versus 6685 eV, respectively), as expected because of the strong enhancement of emission from the forbidden and intercombination lines, relative to the resonance line, in charge-exchange spectra. In contrast, the Fe XXVI high-n Lyman lines have a summed intensity greater than that of Ly-alpha, and are substantially stronger than predicted from the...

  10. Robust Estimation of Cronbach's Alpha

    OpenAIRE

    Christmann, A.; Van Aelst, Stefan

    2002-01-01

    Cronbach’s alpha is a popular method to measure reliability, e.g. in quantifying the reliability of a score to summarize the information of several items in question- naires. The alpha coefficient is known to be non-robust. We study the behavior of this coefficient in different settings to identify situations, which can easily occur in practice, but under which the Cronbach’s alpha coefficient is extremely sensitive to violations of the classical model assumptions. Furthermore,...

  11. On the effect of the ionising background on the Ly{\\alpha} forest autocorrelation function

    OpenAIRE

    Gontcho, Satya Gontcho A; Miralda-Escudé, Jordi; Busca, Nicolás G.

    2014-01-01

    An analytical framework is presented to understand the effects of a fluctuating intensity of the cosmic ionising background on the correlations of the Ly{\\alpha} forest transmission fraction measured in quasar spectra. In the absence of intensity fluctuations, the Ly{\\alpha} power spectrum should have the expected cold dark matter power spectrum with redshift distortions in the linear regime, with a bias factor b_{\\delta} and a redshift distortion parameter {\\beta} that depend on redshift but...

  12. Alpha particles (citations from the International Aerospace Abstracts data base). Report for 1974-July 1979

    International Nuclear Information System (INIS)

    This bibliography of citations to the international literature covers various aspects of alpha particles as applied to controlled fusion devices, solar activity, and geomagnetically trapped particles. Included are articles concerning Tokamak devices, plasma heating and control, plasma-particle interactions, solar particles, solar wind, solar flares, energy spectra, and magnetohydrodynamic stability. Articles concerning effects of alpha particles on different kinds of devices are also included

  13. Evaluation of (alpha,n) Induced Neutrons as a Background for Dark Matter Experiments

    OpenAIRE

    Mei, D.-M.; C. Zhang; Hime, A.

    2008-01-01

    Neutrons from ($\\alpha$,n) reactions through thorium and uranium decays are important sources of background for direct dark matter detection. The neutron yields and energy spectra from a range of materials that are used to build dark matter detectors are calculated and tabulated. In addition to thorium and uranium decays, we found that $\\alpha$ particles from samarium, often the dopant of the window materials of photomultiplier tubes (PMT), are also an important source of neutron yield. The r...

  14. A multichannel model for clusters of an $\\alpha$ and select $N=Z$ nuclei

    OpenAIRE

    Amos, K.; Canton, L.; Fraser, P. R.; Karataglidis, S.; Svenne, J. P.; van der Knijff, D.

    2014-01-01

    A multi-channel algebraic scattering (MCAS) method has been used to solve coupled sets of Lippmann-Schwinger equations for $\\alpha$+nucleus systems to find spectra of the compound systems. Low energy spectra for ${}^{12}$C, ${}^{16}$O, and ${}^{20}$Ne are found with the systems considered as the coupling of an $\\alpha$ particle with low-excitation states of the core nuclei, ${}^8$Be, ${}^{12}$C, and ${}^{16}$O, respectively. Collective models have been used to define the matrices of interacti...

  15. Detecting Damped Lyman-$\\alpha$ Absorbers with Gaussian Processes

    CERN Document Server

    Garnett, Roman; Bird, Simeon; Schneider, Jeff

    2016-01-01

    We develop an automated technique for detecting damped Lyman-$\\alpha$ absorbers (DLAs) along spectroscopic sightlines to quasi-stellar objects (QSOs or quasars). The detection of DLAs in large-scale spectroscopic surveys such as SDSS-III sheds light on galaxy formation at high redshift, showing the nucleation of galaxies from diffuse gas. We use nearly 50 000 QSO spectra to learn a novel tailored Gaussian process model for quasar emission spectra, which we apply to the DLA detection problem via Bayesian model selection. We propose models for identifying an arbitrary number of DLAs along a given line of sight. We demonstrate our method's effectiveness using a large-scale validation experiment, with excellent performance. We also provide a catalog of our results applied to 162 861 spectra from SDSS-III data release 12.

  16. Alpha glucosidase inhibitors.

    Science.gov (United States)

    Kalra, Sanjay

    2014-04-01

    Alpha glucosidase inhibitors (AGIs) are a unique class of anti-diabetic drugs. Derived from bacteria, these oral drugs are enzyme inhibitors which do not have a pancreato -centred mechanism of action. Working to delay carbohydrate absorption in the gastrointestinal tract, they control postprandial hyperglycaemia and provide unquestioned cardiovascular benefit. Specially suited for a traditional Pakistani carbohydrate-rich diet, AGIs have been termed the 'untapped diamonds' of diabetology. The use of these oral antidiabetic drugs (OADs) that target pathophysiology in the early stages of type 2 diabetes, notably to reduce postprandial hyperglycaemia and hyperinsulinaemia will inevitably increase with time. This review describes the history of their development, mechanism of action, basic and clinical pharmacology, and suggests practical, evidence-based guidance for their optimal use. PMID:24864650

  17. The distribution of alpha elements in Andromeda dwarf galaxies

    International Nuclear Information System (INIS)

    We present alpha to iron abundance ratios for 226 individual red giant branch stars in nine dwarf galaxies of the Andromeda (M31) satellite system. The abundances are measured from the combined signal of Mg, Si, Ca, and Ti lines in Keck/DEIMOS medium-resolution spectra. This constitutes the first large sample of alpha abundance ratios measured in the M31 satellite system. The dwarf galaxies in our sample exhibit a variety of alpha abundance ratios, with the average values in each galaxy ranging from approximately solar ([α/Fe] ∼ + 0.0) to alpha-enhanced ([α/Fe] ∼ + 0.5). These variations do not show a correlation with internal kinematics, environment, or stellar density. We confirm radial gradients in the iron abundance of two galaxies out of the five with sufficient data (NGC 185 and And II). There is only tentative evidence for an alpha abundance radial gradient in NGC 185. We homogeneously compare our results to the Milky Way classical dwarf spheroidals, finding evidence for wider variation in average alpha abundance. In the absence of chemical abundances for the M31 stellar halo, we compare to the Milky Way stellar halo. A stellar halo comprised of disrupted M31 satellites is too metal-rich and inconsistent with the Milky Way halo alpha abundance distribution even if considering only satellites with predominantly old stellar populations. The M31 satellite population provides a second system in which to study chemical abundances of dwarf galaxies and reveals a wider variety of abundance patterns than the Milky Way.

  18. Alpha-resonant states in {sup 13}C

    Energy Technology Data Exchange (ETDEWEB)

    Borello-Lewin, T.; Rodrigues, M.R.D.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Souza, M.A.; Miyake, H. [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Cunsolo, A.; Cappuzzello, F. [Universita di Catania (Italy); Istituto Nazionali di Fisica Nucleare (INFN), Catania (Italy). Lab. Nazionali del Sud; Ukita, G.M. [Universidade de Santo Amaro (UNISA), Sao Paulo, SP (Brazil). Faculty of Psychology

    2010-07-01

    Full text: The research program in progress aims to achieve a better understanding of the alpha-clustering phenomenon in light (x{alpha} + {nu}) nuclei. The {sup 9}Be({sup 6}Li,d){sup 13}C reaction was used in the present work to investigate alpha resonant states in {sup 13}C up to 15 MeV of excitation. The data have been taken at a bombarding energy of 25.5 MeV employing the Sao Paulo Pelletron-Enge-Spectrograph facility and the nuclear emulsion detection technique. The plates covered 100 cm along the focal surface and spectra were measured at seven scattering angles, between 3 deg and 20 degrees in the laboratory frame. The resolution of 50 keV allowed for the separation of the resonant contributions to the known 7/2{sup -} at 10.753 MeV and (5/2{sup -}) at 10.818 MeV {sup 13}C states. Particularly interesting is the the narrow alpha resonance seen at E{sub x} = 12.3 MeV close the (3{alpha} + n) threshold, not previously measured, populated by an L = 2 transfer. Detected, near this threshold by alpha inelastic scattering, a large E0 isoscalar transition, the signature of a spatially developed 1/2{sup -} cluster-state, was reported by T. Kawabata. The L = 2 transfer agrees with the 1/2{sup -} attribution. The present work is underway. Taking the benefit of the use of the emulsion plates and applying the track selective reading methodology, at least other three narrow alpha resonances in {sup 13}C up to 15 MeV of excitation, not previously measured, were detected. (author)

  19. An integral field spectroscopic survey for high redshift damped Lyman-alpha galaxies

    OpenAIRE

    Christensen, L; Wisotzki, L.; Roth, M. M.; Sanchez, S. F.; Kelz, A.; Jahnke, K.

    2007-01-01

    We search for galaxy counterparts to damped Lyman-alpha absorbers (DLAs) at z>2 towards nine quasars, which have 14 DLAs and 8 sub-DLAs in their spectra. We use integral field spectroscopy to search for Ly-alpha emission line objects at the redshifts of the absorption systems. Besides recovering two previously confirmed objects, we find six statistically significant candidate Ly-alpha emission line objects. The candidates are identified as having wavelengths close to the DLA line where the ba...

  20. The 1997 IAEA intercomparison of commercially available PC-based software for alpha-particle spectrometry

    CERN Document Server

    Blaauw, M; Woods, S; Fazinic, S

    1999-01-01

    Four commercially available, PC-based analysis programs for alpha-particle spectrometry were compared using the 1997 IAEA test spectra, i.e. AlphaVision 1.20 (EG and G Ortec, USA), Alps 4.21 (Westmeier GmbH, Germany), Winner Alpha 4.0f5 (Eurisys Mesures, France) and Genie-2000 (Canberra Industries Inc., USA). A systematic statistical study of the analysis results was performed based on z-scores. The results indicate that the four programs leave room for substantial improvement.

  1. Anisotropic spectra of acoustic turbulence

    International Nuclear Information System (INIS)

    We found universal anizopropic spectra of acoustic turbulence with the linear dispersion law ω(k)=ck within the framework of generalized kinetic equation which takes into account the finite time of three-wave interactions. This anisotropic spectra can assume both scale-invariant and non-scale-invariant form. The implications for the evolution of the acoustic turbulence with nonisotropic pumping are discussed. The main result of the article is that the spectra of acoustic turbulence tend to become more isotropic. (c) 2000 The American Physical Society

  2. Insurance - Piper Alpha ''et al''

    International Nuclear Information System (INIS)

    This paper opens with some brief information about the Piper Alpha loss, how the loss was handled and its final cost. More importantly, it discusses the effect of the Piper Alpha loss on the world insurance market including the oil insurance captives such as O.I.L Limited. Finally, the insurance market current status and prognosis for the future are considered. (Author)

  3. Long-range alpha detector

    International Nuclear Information System (INIS)

    Historically, alpha-particle and alpha-contamination detectors have been limited by the very short range of alpha particles in air and by relatively poor sensitivity even if the particles are intercepted. Alpha detectors have had to be operated in a vacuum or in close proximity to the source if reasonable efficiency is desired. Alpha particles interact with the ambient air, producing ionization in the air at the rate of ∼30,000 ion pairs per mega-electron-volt of alpha energy. These charges can be transported over significant distances (several meters) in a moving current of air generated by a small fan. An ion chamber located in front of the fan measures the current carried by the moving ions. The long-range alpha detector (LRAD) offers several advantages over more traditional alpha detectors. First and foremost, it can operate efficiently even if the contamination is not easily accessible. Second, ions generated by contamination in crevices and other unmonitorable locations can be detected if the airflow penetrates those areas. Third, all of the contamination on a large surface will generate ions that can be detected in a single detector; hence, the detector's sensitivity to distributed sources is not limited by the size of the probe. Finally, a simple ion chamber can detect very small electric currents, making this technique potentially quite sensitive

  4. Alpha particle emitters in medicine

    International Nuclear Information System (INIS)

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 (211At) and natural bismuth-212 (212Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 (223Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs

  5. The Lyman alpha reference sample

    DEFF Research Database (Denmark)

    Hayes, M.; Östlin, G.; Schaerer, D.; Verhamme, A.; Mas-Hesse, J.M.; Adamo, A.; Atek, H.; Cannon, J.M.; Duval, F.; Guaita, L.; Herenz, E.C.; Kunth, D.; Laursen, Peter; Melinder, J.; Orlitová, I.; Otí-Floranes, H.; Sandberg, A.

    2013-01-01

    We report on new imaging observations of the Lyman alpha emission line (Lyα), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028

  6. Sensitivities of five alpha continuous air monitors for detection of airborne {sup 239}Pu

    Energy Technology Data Exchange (ETDEWEB)

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  7. Sensitivities of five alpha continuous air monitors for detection of airborne sup 239 Pu

    Energy Technology Data Exchange (ETDEWEB)

    McIsaac, C.V.; Amaro, C.R.

    1992-07-01

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne {sup 239}Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of {sup 239}Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne {sup 239}Pu are described.

  8. Sensitivities of five alpha continuous air monitors for detection of airborne 239Pu

    International Nuclear Information System (INIS)

    Results of measurements of the sensitivities of five alpha continuous air monitors (CAMs) for detection of airborne 239Pu are presented. Four commercially available alpha CAMs (Kurz model 8311, Merlin Gerin Edgar, RADeCO model 452, and Victoreen model 758) and a prototype alpha CAM currently in use at Argonne National Laboratory- West (ANL-W) were tested sampling natural ambient air and laboratory-generated atmospheres laden with either blank dust or dust containing nCi/g concentrations of 239Pu. Cumulative alpha spectra were stored at 30 or 60 minute intervals during each sampling and were subsequently analyzed using three different commonly used alpha spectrum analysis algorithms. The effect of airborne dust concentration and sample filter porosity on detector resolution and sensitivity for airborne 239Pu are described

  9. The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, W.T.; Walker, B.A. [Environmental Evaluation Group, Albuquerque, NM (United States)

    1997-08-01

    Waste Isolation Pilot Plant (WIPP) alpha continuous air monitor (CAM) performance was evaluated to determine if CAMs could detect accidental releases of transuranic radioactivity from the underground repository. Anomalous alpha spectra and poor background subtraction were observed and attributed to salt deposits on the CAM sampling filters. Microscopic examination of salt laden sampling filters revealed that aerosol particles were forming dendritic structures on the surface of the sampling filters. Alpha CAM detection efficiency decreased exponentially as salt deposits increased on the sampling filters, suggesting that sampling-filter salt was performing like a fibrous filter rather than a membrane filter. Aerosol particles appeared to penetrate the sampling-filter salt deposits and alpha particle energy was reduced. These findings indicate that alpha CAMs may not be able to detect acute releases of radioactivity, and consequently CAMs are not used as part of the WIPP dynamic confinement system. 12 refs., 12 figs., 1 tab.

  10. Forward Modeling of Reduced Power Spectra From Three-Dimensional $\\mathbf{k}$-Space

    CERN Document Server

    von Papen, Michael

    2015-01-01

    We present results from a numerical forward model to evaluate one-dimensional reduced power spectral densities (PSD) from arbitrary energy distributions in $\\mathbf{k}$-space. In this model, we can separately calculate the diagonal elements of the spectral tensor for incompressible axisymmetric turbulence with vanishing helicity. Given a critically balanced turbulent cascade with $k_\\|\\sim k_\\perp^\\alpha$ and $\\alpha<1$, we explore the implications on the reduced PSD as a function of frequency. The spectra are obtained under the assumption of Taylor's hypothesis. We further investigate the functional dependence of the spectral index $\\kappa$ on the field-to-flow angle $\\theta$ between plasma flow and background magnetic field from MHD to electron kinetic scales. We show that critically balanced turbulence asymptotically develops toward $\\theta$-independent spectra with a slope corresponding to the perpendicular cascade. This occurs at a transition frequency $f_{2D}(L,\\alpha,\\theta)$, which is analytically ...

  11. Alpha Schottky junction energy source

    Science.gov (United States)

    Litz, Marc S.; Fan, Zhaoyang; Carroll, James J.; Bayne, Stephen

    2012-06-01

    Isotope batteries offer solutions for long-lived low-power sensor requirements. Alpha emitting isotopes have energy per decay 103 times that of beta emitters. Alpha particles are absorbed within 20 μm of most materials reducing shielding mitigation. However, damage to materials from the alphas limits their practical use. A Schottky Barrier Diode (SBD) geometry is considered with an alpha emitting contact-layer on a diamond-like crystal semiconductor region. The radiation tolerance of diamond, the safety of alpha particles, combined with the internal field of the SBD is expected to generate current useful for low-power electronic devices over decades. Device design parameters and calculations of the expected current are described.

  12. Chromospheric features of LQ Hydrae from H-alpha line profiles

    CERN Document Server

    Frasca, A; Strassmeier, K G; Biazzo, K

    2008-01-01

    We analyze the H-alpha spectral variability of the rapidly-rotating K1-dwarf LQ Hya using high-resolution H-alpha spectra recorded during April-May 2000. Chromospheric parameters were computed from the H-alpha profile as a function of rotational phase. We find that all these parameters vary in phase, with a higher chromospheric electron density coinciding with the maximum H-alpha emission. We find a clear rotational modulation of the H-alpha emission that is better emphasized by subtracting a reference photospheric template built up with a spectrum of a non-active star of the same spectral type. A geometrical plage model applied to the H-alpha variation curve allows us to derive the location of the active regions that come out to be close in longitude to the most pronounced photospheric spots found with Doppler imaging applied to the photospheric lines in the same spectra. Our analysis suggests that the H-alpha features observed in LQ Hya in 2000 are a scaled-up version of the solar plages as regards dimensio...

  13. Lyman Break Galaxies at z~5: Rest-frame UV Spectra II

    CERN Document Server

    Ando, Masataka; Aoki, Kentaro; Iwata, Ikuru; Ohta, Kouji; Tamura, Naoyuki

    2007-01-01

    We present the results of spectroscopy of Lyman Break Galaxies (LBGs) at z~5 in the J0053+1234 field with the Faint Object Camera and Spectrograph on the Subaru telescope. Among 5 bright candidates with z' < 25.0 mag, 2 objects are confirmed to be at z~5 from their Ly alpha emission and the continuum depression shortward of Ly alpha. The EWs of Ly alpha emission of the 2 LBGs are not so strong to be detected as Ly alpha emitters, and one of them shows strong low-ionized interstellar (LIS) metal absorption lines. Two faint objects with z' \\geq 25.0 mag are also confirmed to be at z~5, and their spectra show strong Ly alpha emission in contrast to the bright ones. These results suggest a deficiency of strong Ly alpha emission in bright LBGs at z~5, which has been discussed in our previous paper. Combined with our previous spectra of LBGs at z~5 obtained around the Hubble Deep Field-North (HDF-N), we made a composite spectrum of UV luminous (M_1400 \\leq -21.5 mag) LBGs at z~5. The resultant spectrum shows a w...

  14. Alpha spectrometry of thick sources. II. Application to the study of radioactive equilibria in uranium ores

    International Nuclear Information System (INIS)

    A method for determining nuclide activities in 4n + 2 uranium series using alpha spectrometry of thick sources is described. This method has been applied to several uranium ores, showing different states of radioactive equilibria. The spectra from samples prepared by cold compression show some anomalies, due to the evolution and later decay of 219Rn and daughters. This phenomenon must be taken in consideration when computing spectra line intensities. (author)

  15. Pileup correction of microdosimetric spectra

    CERN Document Server

    Langen, K M; Lennox, A J; Kroc, T K; De Luca, P M

    2002-01-01

    Microdosimetric spectra were measured at the Fermilab neutron therapy facility using low pressure proportional counters operated in pulse mode. The neutron beam has a very low duty cycle (<0.1%) and consequently a high instantaneous dose rate which causes distortions of the microdosimetric spectra due to pulse pileup. The determination of undistorted spectra at this facility necessitated (i) the modified operation of the proton accelerator to reduce the instantaneous dose rate and (ii) the establishment of a computational procedure to correct the measured spectra for remaining pileup distortions. In support of the latter effort, two different pileup simulation algorithms using analytical and Monte-Carlo-based approaches were developed. While the analytical algorithm allows a detailed analysis of pileup processes it only treats two-pulse and three-pulse pileup and its validity is hence restricted. A Monte-Carlo-based pileup algorithm was developed that inherently treats all degrees of pileup. This algorithm...

  16. Correlation Functions and Power Spectra

    DEFF Research Database (Denmark)

    Larsen, Jan

    2006-01-01

    possible to define correlation functions and associated spectra for aperiodic, periodic and random signals although the interpretation is different. Moreover, we will discuss correlation functions when mixing these basic signal types. In addition, the note include several examples for the purpose of......The present lecture note is a supplement to the textbook Digital Signal Processing by J. Proakis and D.G. Manolakis used in the IMM/DTU course 02451 Digital Signal Processing and provides an extended discussion of correlation functions and power spectra. The definitions of correlation functions and...... spectra for discrete-time and continuous-time (analog) signals are pretty similar. Consequently, we confine the discussion mainly to real discrete-time signals. The Appendix contains detailed definitions and properties of correlation functions and spectra for analog as well as discrete-time signals. It is...

  17. Absorption Spectra of Astaxanthin Aggregates

    CERN Document Server

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  18. Nature of the Pygmy Resonance in Continuous Gamma-Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Rekstad, J; Siem, S; Bernstein, L; Schiller, A; Garrett, P; Nelson, R; Guttormsen, M; Algin, E; Voinov, A

    2003-12-01

    Two-step-cascade spectra of the {sup 171}Yb(n, {gamma}{gamma}){sup 172}Yb reaction have been measured using thermal neutrons. They are compared to calculations based on experimental values of the level density and radiative strength function obtained from the {sup 173}Yb({sup 3}He,{alpha}{gamma}){sup 172}Yb reaction. The multipolarity of a 6.5(15) {mu}{sub N}{sup 2} resonance at 3.3(1) MeV in the strength function is determined to be M1 by this comparison.

  19. Spectroscopic study on the interaction of Bacillus subtilis {alpha}-amylase with cetyltrimethylammonium bromide

    Energy Technology Data Exchange (ETDEWEB)

    Omidyan, R., E-mail: r.omidyan@sci.ui.ac.i [Department of Chemistry, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Kazemi, S.H. [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Bordbar, A.K. [Department of Chemistry, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Zaynalpour, S. [Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of)

    2011-06-15

    The interaction between {alpha}-amylase from Bacillus subtilis and cetyltrimethylammonium bromide (CTAB) has been investigated at various temperature conditions using fluorescence and circular dichroism (CD) spectroscopic methods. Fluorescence data revealed that the fluorescence quenching of {alpha}-amylase by CTAB is the result of complex formation between CTAB and {alpha}-amylase. The thermodynamic analysis on the binding interaction data shows that the interactions are strongly exothermic ({Delta}H{sup o}=-17.92 kJ mol{sup -1}) accompanied with increase in entropy ({Delta}S{sup o} between 109 to 135 J mol{sup -1} K{sup -1}). Thus the binding of CTAB to {alpha}-amylase is both enthalpic and entropic driven, which represent the predominate role of both electrostatic and hydrophobic interactions in complex formation process. The values of 2.17x10{sup -3} M{sup -1} and 1.30 have been obtained from associative binding constant (K{sub a}) and stoichiometry of binding number (n), from analysis of fluorescence data, respectively. Circular dichroism spectra showed the substantial conformational changes in secondary structure of {alpha}-amylase due to binding of CTAB, which represents the complete destruction of both secondary and tertiary structure of {alpha}-amylase by CTAB. - Research highlights: {yields} The Fluorescence quenching effect of {alpha}-amylase by CTAB is a consequence of formation {alpha}-amylase-CTAB complex. {yields} The {alpha}-helical analyzing from the CD spectra in the various concentration of CTAB shows strongly deformation of {alpha}-amylase. {yields} Thermodynamic analysis of quenching verify that the interactions are both enthalpy and entropic driven.

  20. Correlation Functions and Power Spectra

    OpenAIRE

    Larsen, Jan

    2006-01-01

    The present lecture note is a supplement to the textbook Digital Signal Processing by J. Proakis and D.G. Manolakis used in the IMM/DTU course 02451 Digital Signal Processing and provides an extended discussion of correlation functions and power spectra. The definitions of correlation functions and spectra for discrete-time and continuous-time (analog) signals are pretty similar. Consequently, we confine the discussion mainly to real discrete-time signals. The Appendix contains detailed defin...

  1. Infrared spectra of some fructans

    OpenAIRE

    Grube, M.; Bekers, M.; Upite, D.; Kaminska, E.

    2002-01-01

    The FT–IR spectra of fructan – inulin (RAFTILINE), widely applied in the food industry and crystalline fructose as the main component of fructans, were studied. Special interest was to study the spectra of the levan precipitate and fructan syrup – produced by Zymomonas mobilis during the fermentation on sucrose–based medium.It was shown that levan precipitate and fructose syrup does not contain lipids and nucleic acids. Levan precipitate consists of ∼93% of fructose and admixture of glucose, ...

  2. Absorption Spectra of Astaxanthin Aggregates

    OpenAIRE

    Olsina, Jan; Durchan, Milan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption...

  3. Evolution of organic aerosol mass spectra upon heating: implications for OA phase and partitioning behavior

    Energy Technology Data Exchange (ETDEWEB)

    UC Davis; Cappa, Christopher D.; Wilson, Kevin R.

    2010-10-28

    Vacuum Ultraviolet (VUV) photoionization mass spectrometry has been used to measure the evolution of chemical composition for two distinct organic aerosol types as they are passed through a thermodenuder at different temperatures. The two organic aerosol types considered are primary lubricating oil (LO) aerosol and secondary aerosol from the alpha-pinene + O3 reaction (alphaP). The evolution of the VUV mass spectra for the two aerosol types with temperature are observed to differ dramatically. For LO particles, the spectra exhibit distinct changes with temperature in which the lower m/z peaks, corresponding to compounds with higher vapor pressures, disappear more rapidly than the high m/z peaks. In contrast, the alphaP aerosol spectrum is essentially unchanged by temperature even though the particles experience significant mass loss due to evaporation. The variations in the LO spectra are found to be quantitatively in agreement with expectations from absorptive partitioning theory whereas the alphaP spectra suggest that the evaporation of alphaP derived aerosol appears to not be governed by partitioning theory. We postulate that this difference arises from the alphaP particles existing as in a glassy state instead of having the expected liquid-like behavior. To reconcile these observations with decades of aerosol growth measurements, which indicate that OA formation is described by equilibrium partitioning, we present a conceptual model wherein the secondary OA is formed and then rapidly converted from an absorbing form to a non-absorbing form. The results suggest that although OA growth may be describable by equilibrium partitioning theory, the properties of organic aerosol once formed may differ significantly from the properties determined in the equilibrium framework.

  4. Response spectra in alluvial soils

    International Nuclear Information System (INIS)

    For aseismic design of structures, the ground motion data is assumed either in the form of ground acceleration as a function of time or indirectly in the form of response spectra. Though the response spectra approach has limitations like not being applicable for nonlinear problems, it is usually used for structures like nuclear power plants. Fifty accelerograms recorded at alluvial sites have been processed. Since different empirical formulas relating acceleration with magnitude and distance give a wide scatter of values, peak ground acceleration alone cannot be the parameter as is assumed by a number of authors. The spectra corresponding to 5% damping have been normalised with respect to three parameters, namely, peak ground acceleration, peak ground velocity and a nondimensional quantity ad/v2. Envelopee of maxima and minima as well as average response spectra has been obtained. A comparison with the USAEC spectra has been made. A relation between ground acceleration, ground velocity and ad/v2 has been obtained which would nearly give the same magnification of the response. A design response spectra for alluvial soils has been recommended. (author)

  5. Spectra of neutrons and fusion charged products produced in a dense laser plasma

    International Nuclear Information System (INIS)

    The possibility of laser-produced plasma diagnostics has been investigated by measuring spectra of neutrons and alpha particles produced in the T(d,n)4He reaction. Using the Monte Carlo method the spectra have been calculated for nine states of the deuterium-tritium plasma with the temperature of 1;5 and 10 keV and the density of 0.2; 1 and 10 g/cm3 respectively. The initial radius of the target was assumed to be 0.01 cm at the density of 0.2 g/cm3. It is shown that the neutron and alpha spectra can serve as plasma diagnostics parameters in laser fusion

  6. The PG X-Ray QSO Sample Links among X-ray, UV & Optical Spectra

    CERN Document Server

    Wills, B J; Laor, A; Wills, D; Wilkes, B J; Ferland, G J; Wills, Beverley J.

    1998-01-01

    A unique, essentially complete sample of 22 QSOs, with high quality soft X-ray spectra from ROSAT, as well as HST and optical spectrophotometry from below Ly-alpha to above H-alpha, is being used to investigate the relationships among the ionizing continuum and the optical and UV continuum, emission and absorption lines. Here we present a first analysis showing that optical `Eigenvector 1' linking steeper soft X-ray spectra with increasing optical Fe II strength, decreasing [O III] 5007 emission, and narrower BLR H-beta emission, extends to the UV emission lines, and is manifested by weaker C IV 1549 emission, stronger Si III] 1892/C III] 1909 ratio, and narrower C III] 1909 emission. Steeper soft X-ray spectra have been linked to higher L/L_Edd ratios, thus apparently linking BLR densities, high and low ionization gas, and kinematics, to the accretion process.

  7. ALPHA freezes antiprotons

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Laboratories like CERN can routinely produce many different types of antiparticles. In 1995, the PS210 experiment formed the first antihydrogen atoms and a few years later, in 2002, ATRAP and ATHENA were already able to produce several thousand of them. However, no experiment in the world has succeeded in ‘trapping’ these anti-atoms in order to study them. This is the goal of the ALPHA experiment, which has recently managed to cool down the antiprotons to just a few Kelvin. This represents a major step towards trapping the anti-atom, thus opening a new avenue into the investigation of antimatter properties.   Members of the ALPHA collaboration working on the apparatus in the Antiproton Decelerator experimental hall at CERN. Just like the atom, the anti-atom is neutral. Unlike the atom, the anti-atom is made up of antiprotons (as opposed to protons in the atom) and positrons (as opposed to electrons). In order to thoroughly study the properties of the anti-atoms, scien...

  8. Synthesis of a precursor for the preparation of 9 alpha,11 alpha-tritiated 5 alpha-androstane-3 alpha,17 beta-diol 17-glucuronide

    International Nuclear Information System (INIS)

    Starting from 11 beta-hydroxytestosterone, the synthesis of a strategic precursor, C-9 (11) unsaturated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide (9a), for the preparation of 9 alpha,11 alpha-tritiated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide has been achieved. The authors optimized the reaction conditions for catalytic reduction employing hydrogen and subsequent base hydrolysis followed by purification on Amberlite XAD-2 resin to obtain the saturated 5 alpha-androstane-3 alpha, 17 beta-diol 17-glucuronide

  9. Measurement of $\\alpha_{s}$ with Radiative Hadronic Events

    CERN Document Server

    Abbiendi, G; Åkesson, P F; Alexander, G; Anagnostou, G; Anderson, K J; Asai, S; Axen, D; Bailey, I; Barberio, E; Barillari, T; Barlow, R J; Batley, R J; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, S; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brown, R M; Burckhart, H J; Campana, S; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Ciocca, C; Csilling, A; Cuffiani, M; Dado, S; Dallavalle, M; de Roeck, A; De Wolf, E A; Desch, K; Dienes, B; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, F; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J W; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, J; Gruwé, M; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Herten, G; Heuer, R D; Hill, J C; Horváth, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanzaki, J; Karlen, D; Kawagoe, K; Kawamoto, T; Keeler, R K; Kellogg, R G; Kennedy, B W; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krasznahorkays, A Jr; Krieger, P; Von Krogh, J; Kühl, T; Kupper, M; Lafferty, G D; Landsman, H; Lanske, D; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A J; Mashimo, T; Mättig, P; McKenna, J; McPherson, R A; Meijers, F; Menges, W; Merritt, F S; Mes, H; Meyer, N; Michelini, A; Mihara, S; Mikenberg, G; Miller, D J; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H A; O'Neale, S W; Oh, A; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Pilcher, J E; Pinfold, J L; Plane, D E; Pooth, O; Przybycien, M; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J M; Rossi, A M; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schiecks, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Skuja, A; Smith, A M; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vollmer, C F; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, J; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L

    2008-01-01

    Hadronic final states with a hard isolated photon are studied using data taken at centre-of-mass energies around the mass of the Z0 boson with the OPAL detector at LEP. The strong coupling alpha S is extracted by comparing data and QCD predictions for event shape observables at average reduced centre-of-mass energies ranging from 24 GeV to 78 GeV, and the energy dependence of alpha S is studied. Our results are consistent with the running of alpha S as predicted by QCD and show that within the uncertainties of our analysis event shapes in hadronic Z0 decays with hard and isolated photon radiation can be described by QCD at reduced centre-of-mass energies. Combining all values from different event shape observables and energies gives alpha S (Mz)=0.1182 pm 0.0015(stat.) pm 0.0101(syst.).

  10. What Powers Lyman alpha Blobs?

    OpenAIRE

    Ao, Y.; Matsuda, Y; Beelen, A.; Henkel, C.; Cen, R.; De Breuck, C.; Francis, P; Kovacs, A.; Lagache, G.; Lehnert, M.; Mao, M; Menten, K. M.; Norris, R; Omont, A.; Tatemastu, K.

    2015-01-01

    Lyman alpha blobs (LABs) are spatially extended lyman alpha nebulae seen at high redshift. The origin of Lyman alpha emission in the LABs is still unclear and under debate. To study their heating mechanism(s), we present Australia Telescope Compact Array (ATCA) observations of the 20 cm radio emission and Herschel PACS and SPIRE measurements of the far-infrared (FIR) emission towards the four LABs in the protocluster J2143-4423 at z=2.38. Among the four LABs, B6 and B7 are detected in the rad...

  11. Sparse Coding for Alpha Matting

    OpenAIRE

    Johnson, Jubin; Varnousfaderani, Ehsan Shahrian; Cholakkal, Hisham; Rajan, Deepu

    2016-01-01

    Existing color sampling based alpha matting methods use the compositing equation to estimate alpha at a pixel from pairs of foreground (F) and background (B) samples. The quality of the matte depends on the selected (F,B) pairs. In this paper, the matting problem is reinterpreted as a sparse coding of pixel features, wherein the sum of the codes gives the estimate of the alpha matte from a set of unpaired F and B samples. A non-parametric probabilistic segmentation provides a certainty measur...

  12. A method for generating floor response spectra through power spectra/response spectra relationship

    International Nuclear Information System (INIS)

    In this work a method is proposed for deriving floor response spectra using probabilistic techniques. By modelling an earthquake as a stationary random process, a relationship may be derived between its power spectral density function (PSDF) and the response spectrum. Thus, given a set of base response spectra, a set of consistent PSDF's can be generated for the base of the structure. Then, making use of standard random vibration theory, PSDF's for points of interest in the structure can be obtained by appropriate multiplication of complex frequency response (transfer) functions with the derived base PSDF's. Finally, response spectra for the points of interest are obtained using the inverse form of the relationship between a PSDF and a response spectrum. To date, the approach outlined above has been used to generate response spectra of points in some actual three-dimensional structures, and comparisons with response spectra for the same points generated by the time history method have been quite favorable. The limited number of cases performed have demonstrated that the method provides close correspondence of results throughout the frequency domain. While more work is needed to completely qualify this approach, initial results have been very promising. If the approach can be completely verified and found acceptable to the appropriate regulatory bodies, considerable savings in the computation of floor response spectra would result. (orig./RW)

  13. Synergistic approach to modeling X-ray spectra

    Energy Technology Data Exchange (ETDEWEB)

    Liedahl, D.A., LLNL

    1998-07-01

    Plasma emission models used in X-ray astronomy need to simulate X-ray spectra from at least thirteen elements. Development of comprehensive models requires large-scale calculations; for example, Fe M-shell spectra, K{alpha} fluorescence from near-neutral ions, and dielectronic recombination satellite spectra from L-shell ions. Current and recent missions (EUVE, ASCA, DXS, etc.) have already demonstrated the need for major, rapid improvements in spectral models. The high-resolution spectra to be acquired with the next generation of X- ray observatories (AXAF, XMM, Astro-E) promise to push spectral models to their limits. Essential to ensuring the quality of calculations used in spectral codes is corroboration in the laboratory, where controlled and precisely measured plasma conditions can be attained. To this end, we are capitalizing on a three-way synergistic relationship that links astrophysical observations, atomic modeling, and experiments using the LLNL Electron Beam Ion Trap (EBIT). After providing a brief orientation concerning the role of plasma emission models in X-ray astronomy, we discuss one example of this interplay.

  14. Computer analysis of ESR spectra

    International Nuclear Information System (INIS)

    Author. Isotropic ESR spectra often display complicated patterns which are difficult to analyze for their hyperfine splitting constants (HSC). To simplify the analysis, we have written a program suitable for PC's for sufficiently iterating simulations of isotropic ESR spectra and determining the simulation which fits the experimental spectra. Chapter one gives a brief introduction to the theory of electron spin resonance (ESR). In chapter two the main concepts of the program are presented. Auto simulate is the main algorithm. It calculates the entire field of valid simulations to ensure that the solution set contains all parameter combinations which produce satisfactory spectra. Auto simulate requires prior knowledge of the HSCs and other parameters needed for the simulation such as the line width, the spectrum width, and the number of magnetic nuclei. Proton Coupling Constant Extraction (PCCE) and autocorrelation are two methods complementing each other to determine the HSCs. Another iterative method based on a systematic application of Monte Carlo method can be applied to generate more accurate values of the line width. In chapter three, the spectra of Naphthalene, Tetracene, Indigo, Ox-indigo semi quinone, thio-indigo and 2,2'-dipyridyl-Na complex free radicals are analyzed. The results are compared to the literature value, good agreement is obtained for different resolution and noise to signal ratios. In the last chapter a print out of the program is presented. The programming language used is Microsoft QuickBASIC version 7.1

  15. Qualitative interpretation of galaxy spectra

    CERN Document Server

    Almeida, J Sanchez; Terlevich, E; Fernandes, R Cid; Morales-Luis, A B

    2012-01-01

    We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis, and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is of general application, it was developed for understanding the nature of the Automatic Spectroscopic K-means based (ASK) template spectra. They resulted from the classification of all the galaxy spectra in the Sloan Digital Sky Survey data release 7 (SDSS-DR7), thus being a comprehensive representation of the galaxy spectra in the local universe. Using the recipe, we give a description of the properties of the gas and the stars that characterize the ASK classes, from those corresponding to passively evolving galaxies, to HII galaxies undergoing a galaxy-wide starburst. The qualitative analysis is found to be in excellent agreement with quantitative analyses of the same spectra. A number of byprodu...

  16. Dynamic fibrils in Ly alpha

    CERN Document Server

    Koza, J; Vourlidas, A

    2008-01-01

    The solar chromosphere and transition region are highly structured regimes of large complexity. A recent breakthrough concerns the identification of dynamic fibrils seen in Halpha. An aim is to find out whether dynamic fibrils are also observable in Ly alpha. We use a brief sequence of four high-resolution Ly alpha filtergrams of the solar limb taken by the Very high Angular resolution ULtraviolet Telescope (VAULT) to identify 50 dynamic fibrils, measure their top trajectories, and fit these with parabolas. Most fibril tops move supersonically. Their decelerations vary from sub- to superballistic. About half show outward acceleration, which may be an artifact from the poor sampling. The similarity between these dynamic fibrils observed in Ly alpha and the ones observed in Halpha suggests that the magnetoacoustic shock excitation proposed for the Halpha dynamic fibrils is also valid for the Ly alpha ones.

  17. Almost Redundant Components in the 3 alpha Faddeev Equation for the Buck, Friedlich and Wheatly alpha alpha Potential

    CERN Document Server

    Fujiwara, Y; Kohno, M

    2004-01-01

    The 3 alpha orthogonality condition model using the Pauli-forbidden bound states of the Buck, Friedlich and Wheatly alpha alpha potential can yield a compact 3 alpha ground state with a large binding energy, in which a small admixture of the redundant components can never be eliminated.

  18. Testing cosmological variations of fundamental physical constants by analysis of quasar spectra

    CERN Document Server

    Varshalovich, D A; Ivanchik, A V; Panchuk, V E; Lanzetta, K M

    1996-01-01

    Contemporary multidimensional cosmological theories predict different variations of fundamental physical constants in course of the cosmological evolution. On the basis of the QSO spectra analysis, we show that the fine-structure constant \\alpha=e^2/(\\hbar c) and the proton-to-electron mass ratio \\mu=m_p/m_e reveal no statistically significant variation over the last 90% of the lifetime of the Universe. At the 2\\sigma significance level, the following upper bounds are obtained for the epoch corresponding to the cosmological redshifts z ~ 3 (i.e., ~ 10 Gyr ago): |\\Delta\\alpha/\\alpha| < 0.00016 and |\\Delta\\mu/\\mu| < 0.00022. The corresponding upper limits to the time-average rates of the constant variations are |d\\alpha/(\\alpha dt)| < 1.6\\times 10^{-14} yr^{-1} and |d\\mu/(\\mu dt)| < 2.2\\times10^{-14} yr^{-1}. These limits serve as criteria for selection of those theoretical models which predict \\alpha and \\mu variation with the cosmological time. In addition, we test a possible anisotropy of the hig...

  19. Alpha thalassaemia in British people.

    OpenAIRE

    Higgs, D R; Ayyub, H.; Clegg, J B; Hill, A V; Nicholls, R D; Teal, H; Wainscoat, J.S. (James S.); Weatherall, D. J.

    1985-01-01

    Although alpha thalassaemia is rare in north Europeans, it has been identified in British people with no known foreign ancestry. Twelve such patients were studied, of whom eight shared a distinctive molecular defect, which was clearly different from defects seen in subjects of Mediterranean or South East Asian origin. A rare but specific form of alpha thalassaemia is therefore present in the British population. In addition, two patients from families of mixed racial origin were encountered wh...

  20. Accelerated Fitting of Stellar Spectra

    CERN Document Server

    Ting, Yuan-Sen; Rix, Hans-Walter

    2016-01-01

    Stellar spectra are often modeled and fit by interpolating within a rectilinear grid of synthetic spectra to derive the stars' labels: stellar parameters and elemental abundances. However, the number of synthetic spectra needed for a rectilinear grid grows exponentially with the label space dimensions, precluding the simultaneous and self-consistent fitting of more than a few elemental abundances. Shortcuts such as fitting subsets of parameters separately can introduce unknown systematics and do not produce correct error covariances in the derived labels. In this paper we present a new approach -- CHAT (Convex Hull Adaptive Tessellation) -- which includes several new ideas for inexpensively generating a sufficient stellar synthetic library, using linear algebra and the concept of an adaptive, data-driven grid. A convex hull approximates the region where the data lie in the label space. A variety of tests with mock datasets demonstrate that CHAT can reduce the number of required synthetic model calculations by...

  1. Studies of energetic confined alphas using the pellet charge exchange diadgnostic on TFTR

    International Nuclear Information System (INIS)

    Results from recent DT experiments on TFIR to measure the energy distribution and radial density profile of fast confined alphas with the use of Li pellets and neutral particle analysis are presented. When a pellet is injected into the plasma, a toroidally extended ablation cloud is formed that travels with the pellet. A small fraction of the fusion alphas incident on the cloud are converted to helium neutrals as a result of electron capture processes. The escaping energetic helium neutrals are analyzed and detected by the neutral particle analyzer. Radially resolved energy spectra of trapped confined alphas in 0.5-2 MeV range and radial alpha density profiles are presented in this paper. The experimental data are compared with modeling results obtained with the TRANSP Monte-Carlo Code and with a specially developed Fokker-Planck Post Processor (FPP) that uses the alpha source distribution produced by TRANSP. Comparison of the experimental data with TRANSP and FPP show that the alphas in the plasma core of sawtooth free discharges in TFIR are well confined and slow down classically. The energy and radial profiles distributions outside the plasma core show the influence of stochastic ripple losses on alphas. Measurements for sawtoothing plasmas show a significant outward radial transport of trapped alphas

  2. QUALITATIVE INTERPRETATION OF GALAXY SPECTRA

    International Nuclear Information System (INIS)

    We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is for general application, it was developed for understanding the nature of the Automatic Spectroscopic K-means-based (ASK) template spectra. They resulted from the classification of all the galaxy spectra in the Sloan Digital Sky Survey data release 7, thus being a comprehensive representation of the galaxy spectra in the local universe. Using the recipe, we give a description of the properties of the gas and the stars that characterize the ASK classes, from those corresponding to passively evolving galaxies, to H II galaxies undergoing a galaxy-wide starburst. The qualitative analysis is found to be in excellent agreement with quantitative analyses of the same spectra. We compare the mean ages of the stellar populations with those inferred using the code STARLIGHT. We also examine the estimated gas-phase metallicity with the metallicities obtained using electron-temperature-based methods. A number of byproducts follow from the analysis. There is a tight correlation between the age of the stellar population and the metallicity of the gas, which is stronger than the correlations between galaxy mass and stellar age, and galaxy mass and gas metallicity. The galaxy spectra are known to follow a one-dimensional sequence, and we identify the luminosity-weighted mean stellar age as the affine parameter that describes the sequence. All ASK classes happen to have a significant fraction of old stars, although spectrum-wise they are outshined by the youngest populations. Old stars are metal-rich or metal-poor depending on whether they reside in passive galaxies or in star-forming galaxies.

  3. QUALITATIVE INTERPRETATION OF GALAXY SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Almeida, J.; Morales-Luis, A. B. [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain); Terlevich, R.; Terlevich, E. [Instituto Nacional de Astrofisica, Optica y Electronica, Tonantzintla, Puebla (Mexico); Cid Fernandes, R., E-mail: jos@iac.es, E-mail: abml@iac.es, E-mail: rjt@ast.cam.ac.uk, E-mail: eterlevi@inaoep.mx, E-mail: cid@astro.ufsc.br [Departamento de Fisica-CFM, Universidade Federal de Santa Catarina, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil)

    2012-09-10

    We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is for general application, it was developed for understanding the nature of the Automatic Spectroscopic K-means-based (ASK) template spectra. They resulted from the classification of all the galaxy spectra in the Sloan Digital Sky Survey data release 7, thus being a comprehensive representation of the galaxy spectra in the local universe. Using the recipe, we give a description of the properties of the gas and the stars that characterize the ASK classes, from those corresponding to passively evolving galaxies, to H II galaxies undergoing a galaxy-wide starburst. The qualitative analysis is found to be in excellent agreement with quantitative analyses of the same spectra. We compare the mean ages of the stellar populations with those inferred using the code STARLIGHT. We also examine the estimated gas-phase metallicity with the metallicities obtained using electron-temperature-based methods. A number of byproducts follow from the analysis. There is a tight correlation between the age of the stellar population and the metallicity of the gas, which is stronger than the correlations between galaxy mass and stellar age, and galaxy mass and gas metallicity. The galaxy spectra are known to follow a one-dimensional sequence, and we identify the luminosity-weighted mean stellar age as the affine parameter that describes the sequence. All ASK classes happen to have a significant fraction of old stars, although spectrum-wise they are outshined by the youngest populations. Old stars are metal-rich or metal-poor depending on whether they reside in passive galaxies or in star-forming galaxies.

  4. Alpha Particle Emission in Fission

    International Nuclear Information System (INIS)

    Soon after it was discovered that alpha particles are occasionally emitted in fission, it was concluded, on the basis of the energy and angular distributions of these particles, that they are emitted from the space between the fragments at times close to that of the snapping of the neck that connects them. It is shown that, independent of any (still unknown) dynamic features of the alpha-particle ejection process, the energy required to emit alpha particles from between the fragments at the indicated time is barely available. Presumably the rareness of alpha particles in fission, and the apparent absence of still heavier ''third'' particles, is associated with the marginal energy supply at the time of actual fragment division. The fact that the total kinetic energy release in so-called ternary fission is roughly equal to that in normal binary fission instead of being about 20 MeV larger is shown to imply that the mean fragment separation at the division time is larger in ternary fission. This is interpreted to indicate that alpha particles are emitted with greatest probability n those fissions where ample energy happens to be provided through the stretching of an abnormally long neck between the fragments before they actually divide. It is suggested that the release of the alpha particles is a sudden rather than adiabatic process. (author)

  5. Alpha particle physics for ITER

    International Nuclear Information System (INIS)

    The paper is devoted to the analysis of a variety of physical processes which, in the ITER EDA configuration, determine the nature of alpha particle heating in the plasma interior and alpha particle losses to the first wall. The paper consists of results from the alpha particle toroidal field (TF) ripple loss calculations and an analysis of alpha particle collective effects including Alfven modes, sawtooth stabilization, etc. It is shown that the ripple loss in the present ITER configuration is only a few per cent, which cannot directly affect the achievement of ignition. In spite of the up-down asymmetry, the loss fraction does not strongly depend on the toroidal drift direction. However, the heat load is highly localized and can be as high as 1 MW/m2 on the top of the protective limiters. Preliminary calculations of toroidicity induced Alfven eigenmode (TAE) stability indicate that high n numbers may be unstable, but the computational tools, needed for reliable quantitative predictions, are still in a state of development. The likelihood of appreciable alpha particle loss will depend on whether TAE modes produce stochastic alpha particle diffusion or not. The effect of fast particles on the m = 1 mode is also discussed. (author). 15 refs, 2 figs, 1 tab

  6. Ultraviolet spectra of planetary nebulae

    International Nuclear Information System (INIS)

    Features observed in infrared spectra suggest that certain very low excitation (VLE) nebulae have low C/O abundance ratios (Cohen and Barlow 1980; Aitken and Roche 1982). Fluxes in the multiplets [O II] lambda 2470 and C II] lambda 2326 have been measured for the VLE nebula He He 2-131 = HD 138403 using IUE high-dispersion spectra. An analysis similar to that of Harrington et al. (1980) for IC 418 gives C/O = 0.3 for He 2-131, compared with C/O = 1.3 for IC 418 and 0.6 for the Sun. (author)

  7. Automatic identification of mass spectra

    International Nuclear Information System (INIS)

    Several approaches to preprocessing and comparison of low resolution mass spectra have been evaluated by various test methods related to library search. It is shown that there is a clear correlation between the nature of any contamination of a spectrum, the basic principle of the transformation or distance measure, and the performance of the identification system. The identification of functionality from low resolution spectra has also been evaluated using several classification methods. It is shown that there is an upper limit to the success of this approach, but also that this can be improved significantly by using a very limited amount of additional information. 10 refs

  8. Energy scale in inclusive spectra

    International Nuclear Information System (INIS)

    Basing on a model, valid in a limited domain of the phase space, it is shown that there is a universal dependence of the inclusive spectra that is not related to the types of initial and detected particles. The only dependence on the reaction quantum numbers is that present in the scale coefficient of the total energy. The presented experimental data provide with an evidence to that the scale coefficient is universal in the whole region of the variables and its value is related to the behaviour of spectra in the central region

  9. Energy scale in inclusive spectra

    Energy Technology Data Exchange (ETDEWEB)

    Likhoded, A.K.; Tolstenkov, A.N.

    1976-07-01

    It is shown, on the basis of a model that is valid in a certain limited phase-space region, that a universal relation exists for the inclusive spectra which is not connected with the type of the initial and detected particles. The entire dependence on the quantum numbers of the reaction is contained in a redefined scale coefficient for the total energy. The experimental data presented favor the assumption that the scale coefficient is universal in the entire range of the variables and that its value is connected with the behavior of the spectra in the central region. (AIP)

  10. Excitation spectra in Kondo insulators

    International Nuclear Information System (INIS)

    It is shown that the exotic strong local characters in the Kondo insulator are difficult to understand based on the band model and the localized Kondo electron model based on the local picture can explain the essential characteristics, in particular characteristic excitation spectra with two peak structure, which is caused through the transition of the localized Kondo electron. Excitation spectra in SmB6, YbB12 and Ce3Bi4Pt3 are shown to be explained by the above model. On the other hand, that of the pseudo gap Kondo insulator CeNiSn is shown to be substantially different. (orig.)

  11. Investigation of gamma spectra analysis

    International Nuclear Information System (INIS)

    During the investigation of radiation fingerprint comparison, it is found out that the popular gamma spectra analysis softwares are faultful, which decrease the precision of radiation fingerprint comparison. So a new analysis software is development for solving the problems. In order to display the advantage of new program, some typical simulative gamma spectra of radiation source are analyzed respectively by our software and GAMMAVISION and GENNIE2000. The software can be applied not only in nuclear warheads deep-cuts verification, but also in any radiation measurement field. (authors)

  12. AVIRIS spectra of California wetlands

    Science.gov (United States)

    Gross, Michael F.; Ustin, Susan L.; Klemas, Vytautas

    1988-01-01

    Spectral data gathered by the AVIRIS from wetlands in the Suisun Bay area of California on 13 October 1987 were analyzed. Spectra representing stands of numerous vegetation types (including Sesuvium verrucosum, Scirpus acutus and Scirpus californicus, Xanthium strumarium, Cynadon dactylon, and Distichlis spicata) and soil were isolated. Despite some defects in the data, it was possible to detect vegetation features such as differences in the location of the chlorophyll red absorption maximum. Also, differences in cover type spectra were evident in other spectral regions. It was not possible to determine if the observed features represent noise, variability in canopy architecture, or chemical constituents of leaves.

  13. RPL in alpha particle irradiated Ag+-doped phosphate glass

    International Nuclear Information System (INIS)

    The objective of this study is to investigate the emission mechanism of radiophotoluminescence (RPL) in the Ag+-doped phosphate glass (glass dosimeter), which is now used as individual radiation dosimeter, because the emission mechanism of RPL in glass dosimeter has been not fully understood. We have investigated the assignments and characteristics of the X-ray induced color centers in the Ag+-doped phosphate glass up to now (Miyamoto et al., 2010). Optical properties such as optical absorption spectra related with alpha-particles and X-rays irradiation were measured for commercially available glass dosimeter. In this study optical properties such as optical absorption spectrum as a function of alpha-particles and X-rays irradiation were measured for commercially available glass dosimeter. Comparison of the RPL in Ag+-doped phosphate glass irradiated with alpha-particles and X-rays is discussed. - Highlights: • A Yellow and blue emission are included in the RPL of Ag+-doped phosphate glass. • The ratio of yellow and blue emission was different between alpha and X-ray irradiation. • RPL emission intensity increased in an atmosphere below room temperature

  14. Standalone multidetector alpha-spectrometric counting and analysis system

    International Nuclear Information System (INIS)

    This document describes the usage and maintenance of a standalone radioactivity counting and analysis system called LOW LEVEL PHA. It was developed for use in multi-sample alpha spectrometric analysis. The LOW LEVEL PHA system is controlled by a MIK-11/2 microcomputer in 28K of memory and utilizes a double density, dual-floppy disk for data storage. Detectors are interfaced to the computer via CAMAC equipment (Computer Automated Measurement and Control). The system supports 32 simultaneously active and independent alpha particle detectors. It operates with collection rates of up to 300 counts per second from all active detectors, using 128 channels per spectrum and a dynamic energy range of 1.5 MeV. The system is not limited, however, to these conditions. In addition to spectral acquisition, the system provides several analysis functions which include peak identification, curve-smoothing, integration, linear and logarithmic scale graphics, and corrections for base-line shift, deadtime, and background counts. These functions can be implemented while other spectra are being collected. The LOW LEVEL PHA system represents a highly cost-effective means of acquiring alpha spectrometric data from a large number of samples simultaneously, with rapid data analysis capability. This is particularly suitable to analytical and environmental research applications where a small number of alpha-emitting radionuclides are measured at a time, e.g., isotopes of Pu or Am. 23 figures

  15. Lithium abundances in high- and low-alpha halo stars

    DEFF Research Database (Denmark)

    Nissen, P. E.; Schuster, W. J.

    2012-01-01

    ``high-alpha '' stars were formed in situ in the inner parts of the Galaxy, whereas the ``low-alpha '' ones have been accreted from satellite galaxies. In order to see if there is any systematic difference in the lithium abundances of high- and low-alpha stars, equivalent widths of the iLi 6707.8 Å line...... have been measured from VLT/UVES and NOT/FIES spectra and used to derive Li abundances. Furthermore, stellar masses are determined from evolutionary tracks in the log T_eff - log g diagram. For stars with masses 0.7 < M/M☉ < 0.9 and heavy-element fractions 0.001 ⪉ Z < 0.006, the lithium abundance is...... high- and low-alpha stars agrees well, which underlines the universality of the origin of lithium. We suggest that these old halo stars were formed with a lithium abundance close to the primordial value, and that lithium in their atmospheres has been depleted in timea with an approximately linear...

  16. The Alpha Centauri Binary System: Atmospheric Parameters and Element Abundances

    CERN Document Server

    de Mello, G F Porto; Keller, G R

    2008-01-01

    The Alpha Centauri binary system, owing to its binarity, proximity and brightness, is a fundamental calibrating object for the theory of stellar structure and evolution. This role, however, is hindered by a considerable disagreement in the published analyses of its atmospheric parameters and abundances. We report a detailed spectroscopic analysis of both components of the Alpha Centauri binary system, differentially with respect to the Sun, based on high quality spectra (R = 35 000, S/N > 1000). The atmospheric parameters of the system are found to be Teff = 5820 K, [Fe/H] = +0.24, log g = 4.34 and xi = 1.46 km/s, for Alpha Cen A, and Teff = 5240 K, [Fe/H] = +0.25, log g = 4.44 and xi = 1.28 km/s for Alpha Cen B. The parameters were derived from the simultaneous excitation & ionization equilibria of the equivalent widths of Fe I and Fe II lines, by fitting theoretical profiles to the Halpha line and from photometric calibrations, good agreement being reached between the criteria for both stars. We derived...

  17. Broadband distortion modeling in Lyman-$\\alpha$ forest BAO fitting

    CERN Document Server

    Blomqvist, Michael; Bautista, Julian E; Ariño, Andreu; Busca, Nicolás G; Miralda-Escudé, Jordi; Slosar, Anže; Font-Ribera, Andreu; Margala, Daniel; Schneider, Donald P; Vazquez, Jose A

    2015-01-01

    In recent years, the Lyman-$\\alpha$ absorption observed in the spectra of high-redshift quasars has been used as a tracer of large-scale structure by means of the three-dimensional Lyman-$\\alpha$ forest auto-correlation function at redshift $z\\simeq 2.3$, but the need to fit the quasar continuum in every absorption spectrum introduces a broadband distortion that is difficult to correct and causes a systematic error for measuring any broadband properties. We describe a $k$-space model for this broadband distortion based on a multiplicative correction to the power spectrum of the transmitted flux fraction that suppresses power on scales corresponding to the typical length of a Lyman-$\\alpha$ forest spectrum. Implementing the distortion model in fits for the baryon acoustic oscillation (BAO) peak position in the Lyman-$\\alpha$ forest auto-correlation, we find that the fitting method recovers the input values of the linear bias parameter $b_{F}$ and the redshift-space distortion parameter $\\beta_{F}$ for mock dat...

  18. Evolutionary stellar population synthesis with MILES - II. Scaled-solar and \\alpha-enhanced models

    CERN Document Server

    Vazdekis, A; Cassisi, S; Ricciardelli, E; Falcón-Barroso, J; Sánchez-Blázquez, P; La Barbera, F; Beasley, M A; Pietrinferni, A

    2015-01-01

    We present models that predict spectra of old- and intermediate-aged stellar populations at 2.51\\AA\\ (FWHM) with varying [\\alpha/Fe] abundance. The models are based on the MILES library and on corrections from theoretical stellar spectra. The models employ recent [Mg/Fe] determinations for the MILES stars and BaSTI scaled-solar and \\alpha-enhanced isochrones. We compute models for a suite of IMF shapes and slopes, covering a wide age/metallicity range. Using BaSTI, we also compute "base models" matching The Galactic abundance pattern. We confirm that the \\alpha-enhanced models show a flux excess with respect to the scaled-solar models blue-ward $\\sim$4500\\AA, which increases with age and metallicity. We also confirm that both [MgFe] and [MgFe]' indices are [\\alpha/Fe]-insensitive. We show that the sensitivity of the higher order Balmer lines to [\\alpha/Fe] resides in their pseudo-continua, with narrower index definitions yielding lower sensitivity. We confirm that the \\alpha-enhanced models yield bluer (redde...

  19. Spectral Irradiance Calibration in the Infrared. Part 6; 3-35 microns Spectra of Three Southern Standard Stars

    Science.gov (United States)

    Cohen, Martin; Witteborn, Fred C.; Bregman, Jesse D.; Wooden, Diane H.; Salama, Alberto; Metcalfe, Leo

    1996-01-01

    We present three new absolutely calibrated continuous stellar spectra from 3 to 35 microns, constructed as far as possible from actual observed spectral fragments taken from the Kuiper Airborne Observatory (KAO), and the IRAS Low Resolution Spectrometer (LRS). These stars- alpha(sup 1) Cen, alpha TrA, and epsilon Car-augment our previous archive of complete absolutely calibrated spectra for northern K and M giants. All these spectra have a common calibration pedigree. The wavelength coverage is ideal for calibration of many existing and proposed ground-based, airborne, and satellite sensors. KAO and IRAS data in the 15-30 micron range suggest that the spectra of cool giants are close to Rayleigh-Jeans slopes. Our observations of alpha(sup 1) Cen, absolutely calibrated via our adopted Sirius model, indicate an angular diameter in very good agreement with values in the literature, demonstrating 'closure' of the set of spectra within our absolute framework. We compare our observed alpha(sup 1) Cen spectrum with a published grid of theoretical models from Kurucz, and adopt a plausible theoretical shape, that fits our spectrum, as a secondary reference spectrum in the southern sky.

  20. Systematics of Alpha-Radioactivity

    Energy Technology Data Exchange (ETDEWEB)

    Perlman, I.; Ghiorso, A.; Seaborg, G.T.

    1949-09-12

    Correlations of alpha-decay energies in terms of mass number and atomic number have been made for all of the alpha-emitting species now numbering over 100. For each element isotopes show increase in alpha-energy with decrease in mass number except in the region of 126 neutrons where there is an explainable reversal. This reversal has the effect of creating a region of relatively low alpha-energy and long half-life at low mass numbers for such elements as astatine, emanation, francium, and possibly higher elements as had been noted already for bismuth and polonium. Methods and examples of using alpha-decay data to define the energy surface in the heavy element region are discussed. The regularities in alpha-decay are used for predictions of nuclear properties including prediction of the beta-stable nuclides among the heavy elements. The half-life vs. energy correlations show that the even-even nuclides conform well with existing alpha-decay theory, but all nuclear types with odd nucleons show prohibited decay. The reason for this prohibition is not found in spin changes in the alpha-emission but in the assembly of the components of the alpha particle, and this theory is discussed further in terms of observations made on nuclides having two or more alpha-groups. Using most of the even-even nuclei to define 'normal nuclear radius' calculations are now able to show the shrinkage in the regions of lead and of 126 neutrons to amount to about 10%. The much greater change in 'effective radius' for bismuth isotopes can be dissociated into the effects of odd nucleons superimposed on the actual decrease in nuclear radius. The simple expression r = 1.48 A{sup 1/3} {center_dot} 10{sup -13} cm seems to fit the data for the even-even nuclei outside of the region of 126 neutrons better than more complex functions.

  1. $\\alpha $ -Skew $\\pi $ -McCoy Rings

    OpenAIRE

    Areej M. Abduldaim; Chen, Sheng

    2013-01-01

    As a generalization of $\\alpha $ -skew McCoy rings, we introduce the concept of $\\alpha $ -skew $\\pi $ -McCoy rings, and we study the relationships with another two new generalizations, $\\alpha $ -skew ${\\pi }_{1}$ -McCoy rings and $\\alpha $ -skew ${\\pi }_{2}$ -McCoy rings, observing the relations with $\\alpha $ -skew McCoy rings, $\\pi $ -McCoy rings, $\\alpha $ -skew Armendariz rings, $\\pi $ -regular rings, and other kinds of rings. Also, we investigate conditions such that $\\alpha $ -skew ${...

  2. Alpha and conversion electron spectroscopy of 238,239Pu and 241Am and alpha-conversion electron coincidence measurements

    Science.gov (United States)

    Dion, Michael P.; Miller, Brian W.; Warren, Glen A.

    2016-09-01

    A technique to determine the isotopic constituents of a mixed actinide sample has been proposed by a coincident alpha-conversion electron measurement. This presents a unique signature to allow the unfolding of isotopes that possess overlapping alpha particle energy and reduce backgrounds of an unseparated sample. The work presented here are results of conversion electron spectroscopy of 241Am, 238Pu and 239Pu using a dual-stage peltier-cooled 25 mm2 silicon drift detector and alpha spectroscopy with a passivated ion implanted planar silicon detector. The conversion electron spectra were evaluated from 20-55 keV based on fits to the dominant conversion electron emissions, which allowed the relative conversion electron emission intensities to be determined. These measurements provide crucial singles spectral information and calibration to aid in the coincident measurement approach. Furthermore, an alpha-conversion electron spectrometer was assembled using the silicon based detectors described and results of a coincident spectrum analysis is reported for 241Am.

  3. Squeezed States and Helmholtz Spectra

    CERN Document Server

    Francisco Delgado, C; Reyes, M A; Mielnik, Bogdan; Reyes, Marco A

    1997-01-01

    The 'classical interpretation' of the wave function psi(x) reveals an interesting operational aspect of the Helmholtz spectra. It is shown that the traditional Sturm-Liouville problem contains the simplest key to predict the squeezing effect for charged particle states.

  4. Field description of nuclear spectra

    International Nuclear Information System (INIS)

    We discuss the two-nucleon spectra of light and medium nuclei in terms of the meson exchange picture. In particular we compare the OBEP results with a more complete description including higher order processes. Also preliminary results on neutron single particle energies and total binding energies are presented

  5. Inclusive Particle Spectra at RHIC

    OpenAIRE

    Kahana, D. E.; Kahana, S. H.

    2000-01-01

    A simulation is performed of the recently reported data from PHOBOS at energies of 56 and 130 A GeV using the relativistic heavy ion cascade LUCIFER which had previously given a good description of the NA49 inclusive spectra at E=17.2 A GeV. The results compare well with these early measurements at RHIC.

  6. Electron spectra of adatomic structures

    International Nuclear Information System (INIS)

    Within the framework of statistical theory of line-shape in electron elastic scattering and high resolution electron energy loss spectroscopy electronic spectra are studied concerning the problem of the detection of scattering from adatomic complexes and determination of parameters of simple models for the surface structure. 20 refs

  7. Mean Transmitted Flux in the Ly$\\alpha$ Forest From a Sample of 2QZ Quasars

    CERN Document Server

    Polinovskyi, G

    2011-01-01

    The power spectrum of transmitted flux in the Ly$\\alpha$ forest in spectra of distant quasars gives us an information about matter power spectrum on the smallest spatial scales which is very important for testing of different models of dark matter. Only a few independent samples of spectra obtained on diferent instruments have been used for this purpose, thus using of additional independent sample is useful for verification an existing results. We used the data from the 2dF (Two-degree Field) QSO Redshift Survey (2QZ) to obtain the mean transmitted flux for three different redshift bins. After visual inspection and rejection of spectra with broad absorption lines, damped Ly$\\alpha$ systems and low signal-to-noise ratio spectra our final sample contains 655 quasars with redshift range 2.3 $spectra, determination of continuum level for different redshift ranges and the mean transmission in the Ly$\\alpha$ forest as a function of redshift within the range 2.1 $&...

  8. Magnetic properties of single crystal alpha-benzoin oxime: An EPR study

    International Nuclear Information System (INIS)

    The electron paramagnetic resonance (EPR) spectra of gamma irradiated single crystals of alpha-benzoinoxime (ABO) have been examined between 120 and 440 K. Considering the dependence on temperature and the orientation of the spectra of single crystals in the magnetic field, we identified two different radicals formed in irradiated ABO single crystals. To theoretically determine the types of radicals, the most stable structure of ABO was obtained by molecular mechanic and B3LYP/6-31G(d,p) calculations. Four possible radicals were modeled and EPR parameters were calculated for the modeled radicals using the B3LYP method and the TZVP basis set. Calculated values of two modeled radicals were in strong agreement with experimental EPR parameters determined from the spectra. Additional simulated spectra of the modeled radicals, where calculated hyperfine coupling constants were used as starting points for simulations, were well matched with experimental spectra. - Highlights: ► Magnetic properties of alpha-benzoin oxime were investigated, which has not yet been studied by EPR. ► Two stable radicals were found out in the irradiated alpha-benzoin oxime single crystal. ► The behavior of the radicals produced by irradiation are interesting and considerable. ► The effect of irradiation on oxime derivatives is important because of their usage in life.

  9. The Cusp/Core Problem in Galactic Halos: Long-Slit Spectra for a Large Dwarf Galaxy Sample

    CERN Document Server

    Spekkens, K; Spekkens, Kristine; Giovanelli, Riccardo

    2005-01-01

    We derive inner dark matter halo density profiles for a sample of 165 low-mass galaxies using rotation curves obtained from high-quality, long-slit optical spectra assuming minimal disks and spherical symmetry. For $\\rho(r) \\sim r^{-\\alpha}$ near the galaxy center we measure median inner slopes ranging from $\\alpha_m = 0.22 \\pm 0.08$ to $\\alpha_m = 0.28 \\pm 0.06$ for various subsamples of the data. This is similar to values found by other authors, and in stark contrast to the intrinsic cusps ($\\alpha_{int}\\sim1$) predicted by simulations of halo assembly in cold dark matter (CDM) cosmologies. To elucidate the relationship between $\\alpha_m$ and $\\alpha_{int}$ in our data, we simulate long-slit observations of model galaxies with halo shapes broadly consistent with the CDM paradigm. Simulations with $\\alpha_{int}=1/2$ and 1 recover both the observed distribution of $\\alpha_m$ and correlations between $\\alpha_m$ and primary observational parameters such as distance and disk inclination, whereas those with $\\alp...

  10. Lattice dynamics of {alpha} boron and of boron carbide; Proprietes vibrationnelles du bore {alpha} et du carbure de bore

    Energy Technology Data Exchange (ETDEWEB)

    Vast, N

    1999-07-01

    The atomic structure and the lattice dynamics of {alpha} boron and of B{sub 4}C boron carbide have been studied by Density Functional Theory (D.F.T.) and Density Functional Perturbation Theory (D.F.P.T.). The bulk moduli of the unit-cell and of the icosahedron have been investigated, and the equation of state at zero temperature has been determined. In {alpha} boron, Raman diffusion and infrared absorption have been studied under pressure, and the theoretical and experimental Grueneisen coefficients have been compared. In boron carbide, inspection of the theoretical and experimental vibrational spectra has led to the determination of the atomic structure of B{sub 4}C. Finally, the effects of isotopic disorder have been modeled by an exact method beyond the mean-field approximation, and the effects onto the Raman lines has been investigated. The method has been applied to isotopic alloys of diamond and germanium. (author)

  11. Skyshine spectra of gamma rays

    International Nuclear Information System (INIS)

    A study of the spectra of gamma photons back-scattered in vertical direction by infinite air above ground (skyshine) is presented. The source for these measurements is a 650 Ci Cobalt-60 point-source and the skyshine spectra are reported for distances from 150 m to 325 m from the source, measured with a 5 cm x 5 cm NaI(Tl) detector collimated with collimators of 12 mm and 20 mm diameter and 5 cm length. These continuous spectra are unfolded with Gold's iterative technique. The photon-spectra so obtained have a distinct line at 72 keV due to multiply-scattered photons. This is an energy where photoelectric and Compton cross-sections for multiply-scattered photons balance each other. The intensity of the line(I) decreases exponentially with distance (d) from the source obeying a relation of the type I = Isub(o)esup(-μd) where μ is called as ''Multiply-Scatter Coefficient'', a constant of the medium which is air in these measurements. This relationship is explained in terms of a halo around the source comprising of multiply-scattered gamma photons, Isub(0) being the intensity of these scattered photons at the location of cobalt-source. A fraction called as ''Back-scattered Fraction'', the ratio of Isub(0) to the number of original photons from the cobalt-source entering the infinite air, is also calculated. It is shown that with a properly calibrated detector system, this fraction can be used to determine the strength of a large gamma source, viz. a nuclear explosion in air, and for mineral prospecting. These conclusions are general and can be applied to any other infinite medium. Some forward-scatter (transmission) spectra of cobalt-60 source through 10 cm of Pb and 2.5 cm of Al are also reported. (auth.)

  12. Quasar ionization of Lyman-alpha clouds - the proximity effect, a probe of the ultraviolet background at high redshift

    International Nuclear Information System (INIS)

    The distribution of lines in the Ly-alpha forests in quasar spectra is examined using spectral data from 19 quasars with emission lines redshifts z sub Q ranging from 1.7 to 3.8. The number density of Ly-alpha lines generally increases with resdhift z, but there exists a countervailing trend of diminishing number density within individual quasar spectra as z tends to z sub Q. Evidence is presented that this countervailing trend is due to enhanced ionization of Ly-alpha clouds by the bright nearby quasars in whose spectra they are observed. It is suggested that this proximity effect should be used as a powerful tool to measure locally the ionizing flux emitted by high-redshift objects. 44 references

  13. Testing cosmological variations of fundamental physical constants by analysis of quasar spectra

    OpenAIRE

    Varshalovich, D. A.; Potekhin, A. Y.; Ivanchik, A. V.; Panchuk, V. E.; Lanzetta, K. M.

    1996-01-01

    Contemporary multidimensional cosmological theories predict different variations of fundamental physical constants in course of the cosmological evolution. On the basis of the QSO spectra analysis, we show that the fine-structure constant \\alpha=e^2/(\\hbar c) and the proton-to-electron mass ratio \\mu=m_p/m_e reveal no statistically significant variation over the last 90% of the lifetime of the Universe. At the 2\\sigma significance level, the following upper bounds are obtained for the epoch c...

  14. Ultraviolet emission lines of Si II in cool star and solar spectra

    OpenAIRE

    Laha, Sibasish; Keenan, Francis P.; Ferland, Gary J.; Ramsbottom, Catherine A.; Aggarwal, Kanti M.; Ayres, Thomas R.; Chatzikos, Marios; van Hoof, Peter A. M.; Williams, Robin J. R.

    2015-01-01

    Recent atomic physics calculations for Si II are employed within the Cloudy modelling code to analyse Hubble Space Telescope (HST) STIS ultraviolet spectra of three cool stars, Beta-Geminorum, Alpha-Centauri A and B, as well as previously published HST/GHRS observations of Alpha-Tau, plus solar quiet Sun data from the High Resolution Telescope and Spectrograph. Discrepancies found previously between theory and observation for line intensity ratios involving the 3s$^{2}$3p $^{2}$P$_{J}$--3s3p$...

  15. Cluster states and alpha particle condensation in 13C

    International Nuclear Information System (INIS)

    The structure of 13C is studied with the semi-microscopic cluster model, 3α+n orthogonality condition model (OCM). The energy spectra of four 1/2- states and three 1/2+ states up to Ex ~ 13 MeV are successfully reproduced, in particular, three monopole transition strengths are in fair agreement with the observed ones. We discuss the cluster states and alpha particle condensation in the 1/2± states appearing around the 12C+n, 9Be+α and 3α+n thresholds. (author)

  16. Constrained Density Functional Calculations of alpha and delta Pu

    Science.gov (United States)

    Eriksson, Olle

    2002-03-01

    The electronic structure of α and δ Pu are described using a modified density functional theory that incorporates localization effects of the 5f shell. It is argued that a Russel-Saunders coupled state involving a 5f^4 multiplet, together with one itinerant 5f electron explains most of the observed ground state properties of δ Pu (equilibrium volume, elastic constants, near degeneracy with the alpha phase). This 5f electrons in the α phase are argued to form itinerant states, that are well described in density functional theory. The two distinctly different electronic ground states give rise to different excitation spectra and a comparison with experimental data is made.

  17. High resolution alpha spectroscopy with low cost photodiodes

    International Nuclear Information System (INIS)

    Energy resolution for α-spectra comparable to that from good quality surface barrier detectors has been obtained with inexpensive commercial silicon photodiodes. Using a low noise charge-sensitive preamplifier, an alpha energy resolution of less than 15 keV (fwhm) was achieved for 5.486 MeV α-particles from 241Am; this performance enables fine structure peaks to be clearly observed for 239Pu, 241Am, and 244Cm in a mixed α-source. The energy response was found to be highly linear and stable over long periods of operation. Results for other radiations are also briefly described. (orig.)

  18. A new alpha-enhanced super-solar metallicity population

    OpenAIRE

    Adibekyan, V. Zh.; Santos, N. C.; Sousa, S. G; Israelian, G.

    2011-01-01

    We performed a uniform and detailed analysis of 1112 high-resolution spectra of FGK dwarfs obtained with the HARPS spectrograph at the ESO 3.6 m telescope (La Silla, Chile). Most stars have effective temperatures 4700 K < Teff < 6300 K and lie in the metallicity range of -1.39 < [Fe/H] < 0.55. Our main goal is to investigate whether there are any differences between the elemental abundance trends (especially [alpha/Fe] ratio) for stars of different subpopulations. The equivalent widths of spe...

  19. Gaseous alpha emitter diffusion studies using alpha track method

    International Nuclear Information System (INIS)

    Using a very accurate and sensitive analysis method such as alpha track method, the SSNTD group was able to undertake studies on the atomic and molecular processes taking place at low speed and/or very low concentrations, such as diffusion of gaseous alpha radionuclides in gaseous media. For practical application reasons, we began to study the diffusion in air for gaseous alpha radionuclides and aerosols carrying solid alpha radionuclides. The used alpha radionuclides were: Rn-222, as gaseous radionuclide and its solid descendants genetically related, attached to different particles from air, as radioactive aerosols. The source was included into an air tight device with a very well known volume. After 40 days, the radioactive equilibrium was established for all descendants, so that in the device there were the Rn-222 and its descendants, each of them having the same activity. The relative amount/activity ratio of each decay product, at any duration, for any initial mass of Ra-226 parent radionuclide, were calculated using the code UURASE, based on the Bateman general equations, for computing the U-238 radioactive series gamma accumulation. This was adapted for alpha accumulation as ALFAURASE programme. The device which contains the Ra-226 source can be coupled to the calibration system or to the diffusion system, without destroying the radioactive equilibrium. At this coupling, only the radioactive concentration is changed due to the variation of the volume. First of all the device was used for calibrating the CR-39 track detectors for both Rn-222 gaseous radionuclide and aerosol concentration measurements using, in the coupled calibration system, a special 'detector-container' equipped/or not with a filter used for radioactive aerosol stopping. The track detectors CR-39 were etched in NaOH 30%, for 7 hours at 70 deg. C and their studies were performed by optical microscopy using a stereo-microscope Wild M7S and a binocular Zeiss Jena microscope. (authors)

  20. Contribution to the study of the alpha-alpha interaction

    International Nuclear Information System (INIS)

    The new variable energy cyclotron at Berkeley that can accelerate an alpha beam up to an energy of 130 MeV and the mass production of lithium diffused junctions have enabled us to perform 2 series of measurement, in the first one we use alpha beams with an energy ranging between 50 and 120 MeV to study alpha-alpha forces in the second one we use the flexibility of the variable energy cyclotron the resonances around 40 MeV, region that can not yet be reached by tandem accelerators. This work is divided into 6 chapters. The first chapter is dedicated to the formalism of partial wave analysis and the theory of the compound nucleus. In the second chapter the author presents the 88 cyclotron at Berkeley and the diffusion chamber, the alpha detectors are lithium diffused junctions made of silicon. The third chapter deals with the experimental methods used and the issue of the reduction of the volume of data. In the fourth chapter the results obtained in the upper part of the energy range are described in terms of complex shifts that allow the description of the α-α interaction at high energy. The very low impact parameter has enabled us to find 2 new components (l=6 and l=8) of the rotational spectrum and to define a more accurate phenomenological potential. The fifth chapter is dedicated to the narrow resonances we have found between 12 and 27 MeV. We present in the last chapter a calculation of the binding energy of C12 in which we have considered the 12C nucleus as formed by 3 alpha particles interacting with each other through the phenomenological potential defined above

  1. Workshop on Precision Measurements of $\\alpha_s$

    Energy Technology Data Exchange (ETDEWEB)

    Bethke, Siegfried; /Munich, Max Planck Inst.; Hoang, Andre H.; /Vienna U.; Kluth, Stefan; /Munich, Max Planck Inst.; Schieck, Jochen; /Munich U.; Stewart, Iain W.; Aoki, S.; Beneke, M.; Bethke, S.; Blumlein, J.; Brambilla, N.; Brodsky, S.; /MIT, LNS

    2011-10-01

    These are the proceedings of the Workshop on Precision Measurements of {alpha}{sub s} held at the Max-Planck-Institute for Physics, Munich, February 9-11, 2011. The workshop explored in depth the determination of {alpha}{sub s}(m{sub Z}) in the {ovr MS} scheme from the key categories where high precision measurements are currently being made, including DIS and global PDF fits, {tau}-decays, electro-weak precision observables and Z-decays, event-shapes, and lattice QCD. These proceedings contain a short summary contribution from the speakers, as well as the lists of authors, conveners, participants, and talks.

  2. The Gunn-Peterson effect and the Lyman $\\alpha$ forest

    CERN Document Server

    Levshakov, S A

    1997-01-01

    We show that spatial correlations in a stochastic large scale velocity field in an otherwise smooth intergalactic medium (homogeneous comoving density) superposed on the general Hubble flow, may cause a `line-like' structure in QSO spectra similar to the population of unsaturated Ly-alpha forest lines which usually are attributed to individual clouds with 10^{11} <= N(HI) <= 5*10^{13} cm^{-2}. Therefore there is no clear observational distinction between a diffuse intergalactic medium and discrete intergalactic clouds. It follows that the HI-density in the diffuse intergalactic medium might be substantially underestimated if it is determined from the observed intensity distribution near the apparent continuum in high resolution spectra of QSOs. Our tentative estimate implies a diffuse neutral hydrogen opacity tau_{GP} = 0.3 at z = 3 and a current baryon density Omega_{IGM} = 0.08$, assuming a Hubble constant H = 70 km s^{-1} Mpc^{-1}.

  3. NIST Databases on Atomic Spectra

    Science.gov (United States)

    Reader, J.; Wiese, W. L.; Martin, W. C.; Musgrove, A.; Fuhr, J. R.

    2002-11-01

    The NIST atomic and molecular spectroscopic databases now available on the World Wide Web through the NIST Physics Laboratory homepage include Atomic Spectra Database, Ground Levels and Ionization Energies for the Neutral Atoms, Spectrum of Platinum Lamp for Ultraviolet Spectrograph Calibration, Bibliographic Database on Atomic Transition Probabilities, Bibliographic Database on Atomic Spectral Line Broadening, and Electron-Impact Ionization Cross Section Database. The Atomic Spectra Database (ASD) [1] offers evaluated data on energy levels, wavelengths, and transition probabilities for atoms and atomic ions. Data are given for some 950 spectra and 70,000 energy levels. About 91,000 spectral lines are included, with transition probabilities for about half of these. Additional data resulting from our ongoing critical compilations will be included in successive new versions of ASD. We plan to include, for example, our recently published data for some 16,000 transitions covering most ions of the iron-group elements, as well as Cu, Kr, and Mo [2]. Our compilations benefit greatly from experimental and theoretical atomic-data research being carried out in the NIST Atomic Physics Division. A new compilation covering spectra of the rare gases in all stages of ionization, for example, revealed a need for improved data in the infrared. We have thus measured these needed data with our high-resolution Fourier transform spectrometer [3]. An upcoming new database will give wavelengths and intensities for the stronger lines of all neutral and singly-ionized atoms, along with energy levels and transition probabilities for the persistent lines [4]. A critical compilation of the transition probabilities of Ba I and Ba II [5] has been completed and several other compilations of atomic transition probabilities are nearing completion. These include data for all spectra of Na, Mg, Al, and Si [6]. Newly compiled data for selected ions of Ne, Mg, Si and S, will form the basis for a new

  4. LkH-alpha 101 - The stellar wind, the surrounding nebula, and an associated radio star cluster

    Science.gov (United States)

    Becker, Robert H.; White, Richard L.

    1988-01-01

    Radio observations of LkH-alpha 101 have been taken to determine the characteristics of the stellar wind from the central star as well as to image the surrounding nebulosity. They also revealed the presence of a high concentration of weak compact radio sources in the neighborhood of LkH-alpha 101, four of which have optical stellar counterparts. Spectra of three of the stars indicate two T Tauri stars and a highly obscured B star.

  5. LkH-alpha 101 - the stellar wind, the surrounding nebula, and an associated radio star cluster

    International Nuclear Information System (INIS)

    Radio observations of LkH-alpha 101 have been taken to determine the characteristics of the stellar wind from the central star as well as to image the surrounding nebulosity. They also revealed the presence of a high concentration of weak compact radio sources in the neighborhood of LkH-alpha 101, four of which have optical stellar counterparts. Spectra of three of the stars indicate two T Tauri stars and a highly obscured B star. 15 references

  6. The AMBRE Project: Stellar parameterisation of the ESO:FEROS archived spectra

    CERN Document Server

    Worley, C C; Recio-Blanco, A; Hill, V; Bijaoui, A; Ordenovic, C

    2012-01-01

    The AMBRE Project is a collaboration between the European Southern Observatory (ESO) and the Observatoire de la Cote d'Azur (OCA) that has been established in order to carry out the determination of stellar atmospheric parameters for the archived spectra of four ESO spectrographs. The analysis of the FEROS archived spectra for their stellar parameters (effective temperatures, surface gravities, global metallicities, alpha element to iron ratios and radial velocities) has been completed in the first phase of the AMBRE Project. From the complete ESO:FEROS archive dataset that was received, a total of 21551 scientific spectra have been identified, covering the period 2005 to 2010. These spectra correspond to ~6285 stars. The determination of the stellar parameters was carried out using the stellar parameterisation algorithm, MATISSE (MATrix Inversion for Spectral SynthEsis), which has been developed at OCA to be used in the analysis of large scale spectroscopic studies in galactic archaeology. An analysis pipeli...

  7. Abundances, charge states, and energy spectra of helium and heavy ions during solar particle events

    Science.gov (United States)

    Gloeckler, G.; Sciambi, R.; Fan, C. Y.; Hovestadt, D.

    1975-01-01

    Carbon and oxygen energy spectra observed during several solar events indicate a systematic deviation of these spectra from a simple power law: the spectra bend down below about 100 keV/nuc and the amount of this bending is highly correlated with the size of the flare, as measured by the 'event averaged' flux of 130-220 keV protons. The energy spectra of helium computed for the same time periods do not show a similar feature. A large variability of the alpha/CNO ratio is found from event to event (from 2 to about 20 at 40 keV/nuc), and in all cases examined the carbon and oxygen nuclei are nearly fully stripped. These results are interpreted as evidence for storage of energetic ions in hot coronal regions, followed by strong adiabatic deceleration.

  8. Space Station alpha joint bearing

    Science.gov (United States)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  9. ALPHA: antihydrogen and fundamental physics

    Science.gov (United States)

    Madsen, Niels

    2014-02-01

    Detailed comparisons of antihydrogen with hydrogen promise to be a fruitful test bed of fundamental symmetries such as the CPT theorem for quantum field theory or studies of gravitational influence on antimatter. With a string of recent successes, starting with the first trapped antihydrogen and recently resulting in the first measurement of a quantum transition in anti-hydrogen, the ALPHA collaboration is well on its way to perform such precision comparisons. We will discuss the key innovative steps that have made these results possible and in particular focus on the detailed work on positron and antiproton preparation to achieve antihydrogen cold enough to trap as well as the unique features of the ALPHA apparatus that has allowed the first quantum transitions in anti-hydrogen to be measured with only a single trapped antihydrogen atom per experiment. We will also look at how ALPHA plans to step from here towards more precise comparisons of matter and antimatter.

  10. Conditioning of alpha bearing wastes

    International Nuclear Information System (INIS)

    Alpha bearing wastes are generated during the reprocessing of spent fuel, mixed oxide fuel fabrication, decommissioning and other activities. The safe and effective management of these wastes is of particular importance owing to the radiotoxicity and long lived characteristics of certain transuranic (TRU) elements. The management of alpha bearing wastes involves a number of stages which include collection, characterization, segregation, treatment, conditioning, transport, storage and disposal. This report describes the currently available matrices and technologies for the conditioning of alpha wastes and relates them to their compatibility with the other stages of the waste management process. The selection of a specific immobilization process is dependent on the waste treatment state and the subsequent handling, transport, storage and disposal requirements. The overall objectives of immobilization are similar for all waste producers and processors, which are to produce: (a) Waste forms with sufficient mechanical, physical and chemical stability to satisfy all stages of handling, transport and storage (referred to as the short term requirements), and (b) Waste forms which will satisfy disposal requirements and inhibit the release of radionuclides to the biosphere (referred to as the long term requirements). Cement and bitumen processes have already been successfully applied to alpha waste conditioning on the industrial scale in many of the IAEA Member States. Cement systems based on BFS and pozzolanic cements have emerged as the principal encapsulation matrices for the full range of alpha bearing wastes. Alternative technologies, such as polymers and ceramics, are being developed for specific waste streams but are unlikely to meet widespread application owing to cost and process complexity. The merits of alpha waste conditioning are improved performance in transport, storage and disposal combined with enhanced public perception of waste management operations. These

  11. Phonon spectra in quantum wires

    Directory of Open Access Journals (Sweden)

    Ilić Dušan

    2007-01-01

    Full Text Available Green's function method, adjusted to bound crystalline structures, was applied to obtain the phonon dispersion law in quantum wires. The condition of the existence of small mechanical atom movements defining phonon spectra can be found by solving the secular equation. This problem was presented graphically for different boundary parameters. The presence of boundaries, as well as the change of boundary parameters, leads to the appearance of new properties of the layered structure. The most important feature is that, beside the allowed energy zones (which are continuous as in the bulk structure, zones of forbidden states appear. Different values of the boundary parameters lead to the appearance of lower and upper energy gaps, or dispersion branches spreading out of the bulk energy zone. The spectra of phonons in corresponding unbound structures were correlated to those in bound structures.

  12. BPS Spectra, Barcodes and Walls

    CERN Document Server

    Cirafici, Michele

    2015-01-01

    BPS spectra give important insights into the non-perturbative regimes of supersymmetric theories. Often from the study of BPS states one can infer properties of the geometrical or algebraic structures underlying such theories. In this paper we approach this problem from the perspective of persistent homology. Persistent homology is at the base of topological data analysis, which aims at extracting topological features out of a set of points. We use these techniques to investigate the topological properties which characterize the spectra of several supersymmetric models in field and string theory. We discuss how such features change upon crossing walls of marginal stability in a few examples. Then we look at the topological properties of the distributions of BPS invariants in string compactifications on compact threefolds, used to engineer black hole microstates. Finally we discuss the interplay between persistent homology and modularity by considering certain number theoretical functions used to count dyons i...

  13. THE BOSS Ly{alpha} FOREST SAMPLE FROM SDSS DATA RELEASE 9

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Khee-Gan [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69115 Heidelberg (Germany); Bailey, Stephen; Carithers, William; Schlegel, David J. [Lawrence Berkeley National Lab, 1 Cyclotron Rd, Berkeley, CA 94720 (United States); Bartsch, Leslie E. [Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213 (United States); Dawson, Kyle S.; Bolton, Adam S. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Salt Lake City, UT 84112 (United States); Kirkby, David; Margala, Daniel; Blomqvist, Michael [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Lundgren, Britt [Department of Astronomy, University of Wisconsin, 475 North Charter Street, Madison, WI 53706 (United States); Palanque-Delabrouille, Nathalie; Yeche, Christophe; Borde, Arnaud [CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette (France); Pieri, Matthew M. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Weinberg, David H. [Department of Astronomy and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States); Aubourg, Eric; Bautista, Julian [APC, Universite Paris Diderot-Paris 7, CNRS/IN2P3, CEA, Observatoire de Paris, 10, rueA. Domon and L. Duquet, Paris (France); Bizyaev, Dmitry; Brewington, Howard, E-mail: lee@mpia.de [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); and others

    2013-03-15

    We present the BOSS Lyman-{alpha} (Ly{alpha}) Forest Sample from SDSS Data Release 9, comprising 54,468 quasar spectra with z{sub qso} > 2.15 suitable for Ly{alpha} forest analysis. This data set probes the intergalactic medium with absorption redshifts 2.0 < z{sub {alpha}} < 5.7 over an area of 3275 deg{sup 2}, and encompasses an approximate comoving volume of 20 h {sup -3} Gpc{sup 3}. With each spectrum, we have included several products designed to aid in Ly{alpha} forest analysis: improved sky masks that flag pixels where data may be unreliable, corrections for known biases in the pipeline estimated noise, masks for the cores of damped Ly{alpha} systems and corrections for their wings, and estimates of the unabsorbed continua so that the observed flux can be converted to a fractional transmission. The continua are derived using a principal component fit to the quasar spectrum redward of rest-frame Ly{alpha} ({lambda} > 1216 A), extrapolated into the forest region and normalized by a linear function to fit the expected evolution of the Ly{alpha} forest mean flux. The estimated continuum errors are {approx}< 5% rms. We also discuss possible systematics arising from uncertain spectrophotometry and artifacts in the flux calibration; global corrections for the latter are provided. Our sample provides a convenient starting point for users to analyze clustering in BOSS Ly{alpha} forest data, and it provides a fiducial data set that can be used to compare results from different analyses of baryon acoustic oscillations in the Ly{alpha} forest. The full data set is available from the SDSS-III DR9 Web site.

  14. Dust Attenuation and H(alpha) Star Formation Rates of Z Approx. 0.5 Galaxies

    Science.gov (United States)

    Ly, Chun; Malkan, Matthew A.; Kashikawa, Nobunari; Ota, Kazuaki; Shimasaku, Kazuhiro; Iye, Masanori; Currie, Thayne

    2012-01-01

    Using deep narrow-band and broad-band imaging, we identify 401 z approximately 0.40 and 249 z approximately 0.49 H-alpha line-emitting galaxies in the Subaru Deep Field. Compared to other H-alpha surveys at similar redshifts, our samples are unique since they probe lower H-alpha luminosities, are augmented with multi-wavelength (rest-frame 1000AA--1.5 microns) coverage, and a large fraction (20%) of our samples has already been spectroscopically confirmed. Our spectra allow us to measure the Balmer decrement for nearly 60 galaxies with H-beta detected above 5-sigma. The Balmer decrements indicate an average extinction of A(H-alpha)=0.7(uparrow){+1.4}_{-0.7} mag. We find that the Balmer decrement systematically increases with higher H-alpha luminosities and with larger stellar masses, in agreement with previous studies with sparser samples. We find that the SFRs estimated from modeling the spectral energy distribution (SED) is reliable---we derived an "intrinsic" H-alpha luminosity which is then reddened assuming the color excess from SED modeling. The SED-predicted H-alpha luminosity agrees with H-alpha narrow-band measurements over 3 dex (rms of 0.25 dex). We then use the SED SFRs to test different statistically-based dust corrections for H-alpha and find that adopting one magnitude of extinction is inappropriate: galaxies with lower luminosities are less reddened. We find that the luminosity-dependent dust correction of Hopkins et al. yields consistent results over 3 dex (rms of 0.3 dex). Our comparisons are only possible by assuming that stellar reddening is roughly half of nebular reddening. The strong correspondence argue that with SED modeling, we can derive reliable intrinsic SFRs even in the absence of H-alpha measurements at z approximately 0.5.

  15. LRAD, semiconductor, and other radiation detectors applied to environmental monitoring for alpha and beta contamination

    International Nuclear Information System (INIS)

    The very short range of alpha particles in air (typically 2 to 3 cm) has severely limited the use of traditional alpha monitors for detecting and identifying small amounts of alpha-producing contamination in soil, water, and other materials. Monitors based on the traditional alpha detector technology are often hard pressed to meet continually increasing sensitivity requirements. The long-range alpha detector (LRAD) avoids the distance restriction by detecting the ions produced by the interaction of alpha particles with air, rather than the alpha particles directly. The ions are swept into an ion detector either by a moving air current (generated by a fan) or a weak electric field. The LRAD is limited by the distance the ions can travel in the ∼5-s ion lifetime (1 to 100 m), rather than by the several-centimeter range of the alpha particles. The LRAD can be used to perform sensitive (less than 10 disintegrations per minute per 100 cm2) field scans of large surface areas (ranging from hundreds of square meters of concrete floor to thousands of square meters of soil). Because the 'active' element in a LRAD is a solid-metal ion collection plate, the detector is relatively inexpensive, easy to service, and quite rugged. However, the LRAD cannot supply any spectroscopic information to help identify the contaminant. Semiconductor, ionization chamber, and other types of particle detector can generate clean spectra from small samples of material and can identify trace amounts of surface contamination. Furthermore, these detectors are rugged enough to use routinely in a mobile laboratory for isotope identification of 'hot spots' located by the LRAD system. The combination of the LRAD with either an alpha spectrometer or a mobile laboratory with other particle detectors has applications for field beta-particle monitoring (such as would result from tritium contamination) as well as alpha particle detection. (author)

  16. The application of alpha spectrometry to the discovery of new elements heavy-ion beam bombardment

    Science.gov (United States)

    Nitschke, J. M.

    1984-06-01

    Starting with polonium in 1898, alpha spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, alpha spectra have proven simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the "natural" alpha decay series led to the very powerful method of "genetically" linking the decay of new elements to the well-established alpha emission of "daughter" and "granddaughter" nuclei. This technique has been used for all recent discoveries of new elements, including Z = 101, thin samples suitable for alpha spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators, new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in helium gas. Subsequent electrical deposition or a helium jet technique yielded samples that were not only thin enough for alpha spectrometry, but also for alpha and beta-recoil experiments. Many variations of these methods have been developed and will be covered in this paper. For the synthesis of element 106, an aerosol-based recoil transport technique was devised. In this most recent experiments, alpha spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10 -1-10 0s for helium jets and 10 1-10 3 s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyse them with These latest techniques. Again, alpha spectrometry will play a major role, since the expected signature for the decay of a SHE is a sequence of alpha decays followed by spontaneous fission.

  17. Phonon spectra in quantum wires

    OpenAIRE

    Ilić Dušan; Raković Dejan; Šetrajčić Jovan

    2007-01-01

    Green's function method, adjusted to bound crystalline structures, was applied to obtain the phonon dispersion law in quantum wires. The condition of the existence of small mechanical atom movements defining phonon spectra can be found by solving the secular equation. This problem was presented graphically for different boundary parameters. The presence of boundaries, as well as the change of boundary parameters, leads to the appearance of new properties of the layered structure. The most imp...

  18. Inclusive Particle Spectra at RHIC

    CERN Document Server

    Kahana, D E

    2000-01-01

    A simulation is performed of the recently reported data from PHOBOS at energies of $\\sqrt{s}=56,130 A$ GeV using the relativistic heavy ion cascade LUCIFER which had previously given a good description of the NA49 inclusive spectra at $\\sqrt{s}=17.2 A$ GeV. The results compare well with these early measurements at RHIC.

  19. Optimal classification of HCI spectra

    OpenAIRE

    Gaigalas, G.; Karpuskiene, R.; Rudzikas, Z.

    2004-01-01

    Energy levels of highly charged ions as a rule cannot be classified using LS coupling due to rapid increase of relativistic effects. It is suggested, for optimal classification of energy spectra, to calculate them in LS coupling and to transform the weights of the wave functions, obtained after diagonalization of the energy matrix, to the other coupling schemes. F-like ions are considered as an example.

  20. Hard MeV-GeV spectra of blazars

    CERN Document Server

    Katarzynski, Krzysztof

    2011-01-01

    Very high energy (VHE) gamma-ray emission from a distant source (z >~0.2) can be efficiently absorbed my means of the electron-positron pair creation process. Analyses of the unabsorbed spectra imply that the intrinsic TeV emission of some blazars is hard, with spectral indices 0.5 ~ 10^3, E=g m_e c^2). In other words, we assume a low energy cut-off in the particle energy distribution. The emission produced by the particles with this energy spectrum can explain hard intrinsic spectra in the energy range from MeV up to TeV. We demonstrate how to estimate the basic physical parameters of a source in this case and how to explain the observed spectra by a precise simulation of the particle energy evolution. To test our estimation methods, we use the observations of two blazars with exceptionally hard spectral indices (alpha <~ 0.5) in the MeV-GeV range and known redshifts: RGB J0710+591 and 1ES 0502+675. The estimated values of the Doppler factor and magnetic field are compared with our numerical simulations, ...

  1. Alpha decay of At-194

    OpenAIRE

    Andreev, Andrei; Antalic, S; Ackermann, D.; Bianco, L.; Franchoo, S.; S. Heinz; F. P. Hessberger; Hofmann, S.; Huyse, Marc; Kojouharov, I.; Kindler, B.; Lommel, B.; Mann, R.; Nishio, K; R.D.Page

    2009-01-01

    Detailed alpha-decay studies of the neutron-deficient isotope At-194 have been performed in the complete fusion reaction Fe-56+Pr-141 -> At-194+3n at the velocity filter SHIP. Two alpha-decaying isomeric states with half-lives of T-1/2(At-194(m1))=310(8) ms and T-1/2(At-194(m2))=253(10) ms were identified in this nucleus. Their complex decays to the states in the daughter nucleus Bi-190 are discussed in the article. We propose that similar to the case of the neighboring At-191,At-192,At-193,A...

  2. Optical Spectra of Triggered Lightning

    Science.gov (United States)

    Walker, T. D.; Biagi, C. J.; Hill, J. D.; Jordan, D. M.; Uman, M. A.; Christian, H. J., Jr.

    2009-12-01

    In August 2009, the first optical spectra of triggered lightning flashes were acquired. Data from two triggered lightning flashes were obtained at the International Center for Lightning Research and Testing in north-central Florida. The spectrometer that was used has an average dispersion of 260 Å/mm resulting in an average resolution of 5 Å when mated to a Photron (SA1.1) high-speed camera. The spectra captured with this system had a free spectral range of 3800-8000 Å. The spectra were captured at 300,000 frames per second. The spectrometer's vertical field of view was 3 m at an altitude 50 m above the launch tower, intended to view the middle of the triggering wire. Preliminary results show that the copper spectrum dominated the earliest part of the flash and copper lines persisted during the total lifetime of the detectable spectrum. Animations over the lifetime of the stroke from the initial wire illumination to multiple return strokes show the evolution of the spectrum. In addition, coordinated high speed channel base current, electric field and imagery measurements of the exploding wire, downward leaders, and return strokes were recorded. Quantitative analysis of the spectral evolution will be discussed in the context of the overall flash development.

  3. Rapid Decline of Lyman-alpha Emission Toward the Reionization Era

    CERN Document Server

    Tilvi, Vithal; Finkelstein, Steven L; Long, James; Song, Mimi; Dickinson, Mark; Ferguson, Henry; Koekemoer, Anton M; Giavalisco, Mauro; Mobasher, Bahram

    2014-01-01

    The observed deficit of strongly Lyman-alpha emitting galaxies at z>6.5 is attributed to either increasing neutral hydrogen in the intergalactic medium (IGM) and/or to the evolving galaxy properties. To investigate this, we have performed very deep near-IR spectroscopy of z>7 galaxies using MOSFIRE on the Keck-I Telescope. We measure the Lyman-alpha fraction at z~8 (combined photometric redshift peak at z=7.7) using two methods. First, we derived NLy{\\alpha}/Ntot directly using extensive simulations to correct for incompleteness. Second, we used a Bayesian formalism (introduced by Treu et al. 2012) that compares the z>7 galaxy spectra to models of the Lyman-alpha equivalent width (WLy{\\alpha}) distribution at z~6. We explored two simple evolutionary scenarios: smooth evolution where Lyman-alpha is attenuated in all galaxies by a constant factor (perhaps owing to processes from galaxy evolution or a slowly increasing IGM opacity), and patchy evolution where Lyman-alpha is blocked in some fraction of galaxies (...

  4. Influence of the repulsive coefficient {alpha} and approximate corresponding states in Mie {alpha}-6 and exponential {alpha}-6 fluids

    Energy Technology Data Exchange (ETDEWEB)

    Galliero, Guillaume [Universite de Marne-la-Vallee, Laboratoire d' Etude des Transferts d' Energie et de Matiere (EA 2546), Bat. Lavoisier, Cite Descartes, Champs-sur-Marne, F-77454 Marne-la-Vallee Cedex 2 (France)], E-mail: galliero@univ-mlv.fr; Boned, Christian; Baylaucq, Antoine [Universite de Pau et des Pays de l' Adour, Laboratoire des Fluides Complexes (UMR-5150), BP 1155, F-64013 Pau Cedex (France); Montel, Francois [TOTAL, CSTJF, Avenue Larribau, F-64018 Pau (France)

    2007-03-30

    Non-equilibrium molecular dynamics (NEMD) simulations of the Mie {alpha}-6 and the exponential {alpha}-6 (exp {alpha}-6) fluids have been carried out for 42 thermodynamic states. Various repulsive coefficients have been studied, {alpha} ranging from 9 to 14 for the Mie {alpha}-6 potentials and from 11 to 16 for the exp {alpha}-6 ones, which corresponds to a total of 603 points of simulation of stable phases. The simulations have shown that, for a given set of reduced temperature and density (using an appropriate scaling procedure), the reduced pressure varies linearly with {radical}({alpha}-6) for the Mie {alpha}-6 potentials and with {radical}({alpha}-7) for the exp {alpha}-6 potentials. Concerning the viscosity, it is shown that, for both potential families, the variation is linear with {alpha}. Thus, an approximate corresponding states scheme exists on pressure and on viscosity for fluids modelled by both potentials families, but only for each property separately. In addition, it appears that, approximate corresponding states exist between fluids modelled by a Mie {alpha}-6 potential and an exp ({alpha} + 2)-6 one for pressure, and between fluids modelled by a Mie {alpha}-6 potential and an exp ({alpha} + 2.5)-6 one for viscosity. So, despite obvious similarities, the influence of the shape of the potential on pressure and on viscosity is not strictly the same. Hence, a complete perfect corresponding states scheme (including both the pressure and the viscosity) seems hardly feasible between fluids modelled by the Mie {alpha}-6 and the exp {alpha}-6 potential families.

  5. Reconstruction of neutron spectra through neural networks

    International Nuclear Information System (INIS)

    A neural network has been used to reconstruct the neutron spectra starting from the counting rates of the detectors of the Bonner sphere spectrophotometric system. A group of 56 neutron spectra was selected to calculate the counting rates that would produce in a Bonner sphere system, with these data and the spectra it was trained the neural network. To prove the performance of the net, 12 spectra were used, 6 were taken of the group used for the training, 3 were obtained of mathematical functions and those other 3 correspond to real spectra. When comparing the original spectra of those reconstructed by the net we find that our net has a poor performance when reconstructing monoenergetic spectra, this attributes it to those characteristic of the spectra used for the training of the neural network, however for the other groups of spectra the results of the net are appropriate with the prospective ones. (Author)

  6. The INES System II: Ripple Correction and Absolute Calibration for IUE High Resolution Spectra

    OpenAIRE

    Cassatella, A.; Altamore, A.; Gonzalez-Riestra, R.; Ponz, J. D.; Barbero, J.; Talavera, A.; Wamsteker, W.

    1999-01-01

    In this paper we document the results of the study which led to the ripple correction and absolute calibration algorithms applied to the high resolution spectra processed with the NEWSIPS software for the Final Archive of the IUE Project. In this analysis, based on a very large number of spectra, we find that both K and the alpha parameters (not only the former as previously believed) vary with order number. This fact, together with the finding that the central peaks of the blaze function var...

  7. Multi-periodic oscillations of alpha Hya

    CERN Document Server

    Setiawan, J; Roth, M

    2005-01-01

    We report the detection of multi-periodic oscillations of the cool evolved star alpha Hya (HD 81797, K3II-III). Two-hundred and forty-three high-resolution spectra (R=48,000) of this star have been obtained in March and April 2005 with FEROS at the 2.2 m-MPG/ESO telescope in La Silla Observatory, Chile. We observed oscillations in the stellar radial velocity and the asymmetry of the spectral line profile. We detected oscillation frequencies of the stellar radial velocity in two frequency regions, nu= 2-30 muHz and nu= 50-120 muHz. The corresponding periods are P= 0.6-5.6 days and P= 2.3-5.5 hours, respectively. In addition to these oscillations we also observed a trend in the radial velocity which shows evidence for a long-term variability. Furthermore, our measurements show a correlation between the variation in the radial velocity and the asymmetry of the spectral line profile, as measured in the bisector velocity spans. The line bisectors also show oscillations in the same frequency regions as those of the...

  8. A Generalized Theory of Varying Alpha

    CERN Document Server

    Barrow, John D

    2011-01-01

    In this paper, we formulate a generalization of the simple Bekenstein-Sandvik-Barrow-Magueijo (BSBM) theory of varying alpha by allowing the coupling constant, \\omega, for the corresponding scalar field \\psi\\ to depend on \\psi. We focus on the situation where \\omega\\ is exponential in \\psi\\ and find the late-time behaviours that occur in matter-dominated and dark-energy dominated cosmologies. We also consider the situation when the background expansion scale factor of the universe evolves in proportion to an arbitrary power of the cosmic time. We find the conditions under which the fine structure `constant' increases with time, as in the BSBM theory, and establish a cosmic no-hair behaviour for accelerating universes. We also find the conditions under which the fine structure `constant' can decrease with time and compare the whole family of models with astronomical data from quasar absorption spectra. Finally, we show that spatial variations on sub-horizon scales can dominate over the cosmological time evolut...

  9. Parametrized spectra, multiplicative Thom spectra, and the twisted Umkehr map

    CERN Document Server

    Ando, Matthew; Gepner, David

    2011-01-01

    We introduce and study a general theory of objects parametrized by spaces, in the setting of infinity categories. This framework specializes to give an infinity categorical model of parametrized spectra, and we apply these foundations to study the multiplicative properties of the generalized Thom spectrum functor. As part of this work we study the Picard space of a presentable monoidal infinity category. We sharpen classical results due to Lewis about the multiplicative properties of the Thom isomorphism. Our main application is the construction of twisted Umkehr maps on twistings of generalized cohomology theories.

  10. Secondary charged particle spectra arising from 14 MeV neutrons

    International Nuclear Information System (INIS)

    This report presents the energy spectra of the charged secondaries arising in a few media under 14 MeV neutron irradiation. Six media are considered. They are C, N, O, CO2, air and soft tissue. The alpha particles and recoiling nuclei due to (n, alpha) events and the recoils produced in elastic and inelastic scattering events are considered in detail. The different excitation levels in which the recoiling nuclei may be left and also their anisotropic angular distributions are taken into account. A total of 43 individual reactions in C, N, and O are considered and five additional reactions could not be included for want of adequate data. Dose- and fluence-average LET's and average energy of these recoils are obtained from the calculated spectra. (author)

  11. Research on the detection of fluxes and spectra of charged particles in space

    CERN Document Server

    Sha Jian Jun; Yu Jin Nan; Zhang Wei Guo; Xiang Hong Wen; Wu Zhong Xiang; Cai Zhen Bo; Zhu Wen Ming

    2002-01-01

    A multi-functional spectrometer-identifier was developed for studying fluxes and spectra of protons, alpha particles, oxygen and iron ions in the near-earth space. The telescope system of this spectrometer consists of three Au-Si surface barrier detectors with different thickness and scintillation CsI (Tl). Owing to adopting the DELTA E-E method in particles identification and improved fast response electronics system in data processing and acquisition system, the spectrometer can be used to simultaneously and separately detect the fluxes and spectra of protons of 1-200 MeV, alpha particles of 1-200 MeV/u(nucleon), oxygen ions of 1.7-496 MeV/u and iron ions of 2.5 MeV-1.0 GeV/u

  12. Predicting Lyman-alpha and Mg II Fluxes from K and M Dwarfs Using GALEX Ultraviolet Photometry

    CERN Document Server

    Shkolnik, Evgenya L; Peacock, Sarah; Barman, Travis S

    2014-01-01

    A star's UV emission can greatly affect the atmospheric chemistry and physical properties of closely orbiting planets with the potential for severe mass loss. In particular, the Lyman-alpha emission line at 1216 Angstroms, which dominates the far-ultraviolet spectrum, is a major source of photodissociation of important atmospheric molecules such as water and methane. The intrinsic flux of Lyman-alpha, however, cannot be directly measured due to the absorption of neutral hydrogen in the interstellar medium and contamination by geocoronal emission. To date, reconstruction of the intrinsic Lyman-alpha line based on Hubble Space Telescope spectra has been accomplished for 46 FGKM nearby stars, 28 of which have also been observed by the Galaxy Evolution Explorer (GALEX). Our investigation provides a correlation between published intrinsic Lyman-alpha and GALEX far- and near-ultraviolet chromospheric fluxes for K and M stars. The negative correlations between the ratio of the Lyman-alpha to the GALEX fluxes reveal ...

  13. K(alpha) X-ray Emission Spectra from Highly Charged Fe Ions in EBIT

    International Nuclear Information System (INIS)

    A detailed spectral model has been developed for the computer simulation of the 2p → 1s Kα X-ray emission from highly charged Fe ions in the Electron Beam Ion Trap (EBIT). The spectral features of interest occur in the range from 1.84 (angstrom) to 1.94 (angstrom). The fundamental radiative emission processes associated with radiationless electron capture or dielectronic recombination, inner-shell electron collisional excitation, and inner-shell electron collisional ionization are taken in account. For comparison, spectral observations and simulations for high-temperature magnetic-fusion (Tokamak) plasmas are reviewed. In these plasmas, small departures from steady-state corona-model charge-state distributions can occur due to ion transport processes, while the assumption of equilibrium (Maxwellian) electron energy distributions is expected to be valid. Our investigations for EBIT have been directed at the identification of spectral features that can serve as diagnostics of extreme non-equilibrium or transient-ionization conditions, and allowance has been made for general (non-Maxwellian) electron energy distributions. For the precise interpretation of the high-resolution X-ray observations, which may involve the analysis of blended spectral features composed of many lines, it has been necessary to take into account the multitude of individual fine-structure components of the Kα radiative transitions in the ions from Fe XVIII to Fe XXV. At electron densities higher than the validity range of the corona-model approximation, collisionally induced transitions among low-lying excited states can play an important role. It is found that inner-shell electron excitation and ionization processes involving the complex intermediate ions from Fe XVIII to Fe XXI produce spectral features, in the wavelength range from 1.89 (angstrom) to 1.94 (angstrom), which are particularly sensitive to density variations and transient ionization conditions.

  14. Neutron, Proton and Alpha Emission Spectra of Nickel Isotopes for Proton Induced Reactions

    Science.gov (United States)

    Tel, E.; Kara, A.

    2012-06-01

    The fusion energy is attractive as an energy source because the fusion will not produce CO2 or SO2 and so fusion will not contribute to environmental problems, such as particulate pollution and excessive CO2 in the atmosphere. The fusion reaction does not produce radioactive nuclides and it is not self-sustaining, as is a fission reaction when a critical mass of fissionable material is assembled. Since the fusion reaction is easily and quickly quenched the primary sources of heat to drive such an accident are heat from radioactive decay and heat from chemical reactions. Both the magnitude and time dependence of the generation of heat from radioactive decay can be controlled by proper selection and design of materials. Nickel (Ni) is an important structural material in fusion (and also fission) reactor technologies and many other fields. So, the working out the reaction cross sections of the Ni isotopes is very important for selection of the fusion materials. In this study, 58Ni(p,xn), 58Ni(p,xp), 60Ni(p,xp), 60Ni(p,xα) and 62Ni(p,xp) reactions have been investigated using nuclear reaction models. And also the 58Ni(p,xn) reaction has been calculated through a method of offered by Tel et al. The calculated results are discussed and compared with the experimental data taken from EXFOR database.

  15. Ionized iron K\\alpha lines in AGN X-ray spectra

    OpenAIRE

    Bianchi, Stefano; Matt, Giorgio

    2002-01-01

    The Equivalent Widths (EW) of the He- and H-like iron lines produced in photoionized, circumnuclear matter of AGN are calculated with respect to both the reflected and the total continua. We found that the EWs with respect tothe total continuum may be as large as a few tens of eV, making them observable in bright Seyfert 1s by instruments on board Chandra and XMM-Newton. We apply our calculations to the XMM-Newton spectrum of NGC 5506 and found a good agreement with the data at the expense of...

  16. What Powers Lyman alpha Blobs?

    CERN Document Server

    Ao, Y; Beelen, A; Henkel, C; Cen, R; De Breuck, C; Francis, P; Kovacs, A; Lagache, G; Lehnert, M; Mao, M; Menten, K M; Norris, R; Omont, A; Tatemastu, K; Weiss, A; Zheng, Z

    2015-01-01

    Lyman alpha blobs (LABs) are spatially extended lyman alpha nebulae seen at high redshift. The origin of Lyman alpha emission in the LABs is still unclear and under debate. To study their heating mechanism(s), we present Australia Telescope Compact Array (ATCA) observations of the 20 cm radio emission and Herschel PACS and SPIRE measurements of the far-infrared (FIR) emission towards the four LABs in the protocluster J2143-4423 at z=2.38. Among the four LABs, B6 and B7 are detected in the radio with fluxes of 67+/-17 microJy and 77+/-16 microJy, respectively, and B5 is marginally detected at 3 sigma (51+/-16 microJy). For all detected sources, their radio positions are consistent with the central positions of the LABs. B6 and B7 are obviously also detected in the FIR. By fitting the data with different templates, we obtained redshifts of 2.20$^{+0.30}_{-0.35}$ for B6 and 2.20$^{+0.45}_{-0.30}$ for B7 which are consistent with the redshift of the lyman alpha emission within uncertainties, indicating that both ...

  17. Alcoholism, Alpha Production, and Biofeedback

    Science.gov (United States)

    Jones, Frances W.; Holmes, David S.

    1976-01-01

    Electroencephalograms of 20 alcoholics and 20 nonalcoholics were obtained. Data indicated that alcoholics produced less alpha than nonalcoholics. In one training condition subjects were given accurate biofeedback, whereas in the other condition subjects were given random (noncontingent) feedback. Accurate biofeedback did not result in greater…

  18. Alpha Testing Escape from Diab

    Science.gov (United States)

    Alpha testing was conducted of sessions 2 and 3 from Diab to assess whether the activities worked as expected, and whether children in the target ages enjoyed it. Data include both RA observations of child performance while playing the games and cognitive interview responses from the players after t...

  19. Monitoring Ly-Alpha Emission From the Blazar 3C 279

    Science.gov (United States)

    Koratkar, Anuradha; Pian, Elena; Urry, C. Megan; Pesce, Joseph E.

    1998-01-01

    The blazar 3C 279 is well studied and shows frequent large continuum flares from radio to gamma-ray wavelengths. There have been a number of multiwavelength observations of 3C 279, and hence there are extensive ultraviolet data for this object available in the UV archives. In this paper we present Ly-alpha emission line measurements for 3C 279 using all the archival IUE SWP spectra from 1988 to 1996 and all archival Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) G190H spectra from 1992 to 1996. Individual archival IUE spectra of 3C 279 show weak Ly-alpha emission at approximately 1868 A (z = 0.536), which is easily seen in the co-added data. The Ly-alpha emission is observed in all the HST/FOS spectra. The strength of Ly-alpha is nearly constant (approximately 5 x 10(exp -14) erg/sq cm.s), while the 1750 A continuum varies by a factor of approximately 50, from approximately 0.6 to 31.6 x 10(exp -15) ergs/sq cm.s.A. The behavior of the Ly-alpha emission line flux and continuum flux is similar to that of the only other well observed blazar, 3C 273, which shows constant line flux while the continuum varies by a factor of approximately 3. This near-constancy of emission-line flux in the two best-studied blazars suggests that the highly variable beamed continuum is not a significant source of photoionization for the gas. Some other source, such as thermal emission from an accretion disk, must be providing a significant fraction of the photoionizing flux in these objects. The large amplitude variability seen at gamma-ray energies must be due to changes in the energetic electrons in the jet rather than changes in the external photon field.

  20. The Characteristic Dimension of Lyman-Alpha Forest Clouds Toward Q0957+561

    Science.gov (United States)

    Dolan, J. F.; Michalitsianos, A. G.; Hill, R. J.; Nguyen, Q. T.; Fisher, Richard (Technical Monitor)

    2000-01-01

    Far-ultraviolet spectra of the gravitational lens components Q0957+561 A and B were obtained with the Hubble Space Telescope Faint Object Spectrograph to investigate the characteristic dimension of Lyman-alpha forest clouds in the direction of the quasar. If one makes the usual assumption that the absorbing structures are spherical clouds with a single radius, that radius can be found analytically from the ratio of Lyman-alpha lines in only one line of sight to the number in both. A simple power series approximation to this solution, accurate everywhere to better than 1%, will be presented. Absorption lines in Q0957+561 having equivalent width greater than 0.3 A in the observer's frame not previously identified as interstellar lines, metal lines, or higher order Lyman lines were taken to be Ly-alpha forest lines. The existence of each line in this consistently selected set was then verified by its presence in two archival FOS spectra with approximately 1.5 times higher signal to noise than our spectra. Ly-alpha forest lines appear at 41 distinct wavelengths in the spectra of the two images. One absorption line in the spectrum of image A has no counterpart in the spectrum of image B, and one line in image B has no counterpart in image A. Based on the separation of the lines of sight over the redshift range searched for Ly-alpha forest lines, the density of the absorbing clouds in the direction of Q0957+561 must change significantly over a radius R = 160 (+120, -70) h (sup -1) (sub 50) kpc (H (sub 0) 50 h (sub 50) km s (sup -1) kpc (sup -1), q (sub 0) = 1/2). The 95% confidence interval on R extends from (50 950) h (sup -1) (sub 50) kpc.

  1. Alpha-particle emission probabilities in the decay of {sup 240}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Sibbens, G., E-mail: goedele.sibbens@ec.europa.e [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium); Pomme, S.; Altzitzoglou, T. [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium); Garcia-Torano, E. [Laboratorio de Metrologia de Radiaciones Ionizantes, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Janssen, H.; Dersch, R.; Ott, O. [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Martin Sanchez, A. [Departamento de Fisica, Universidad de Extremadura, Badajoz, E-06071 (Spain); Rubio Montero, M.P. [Departamento de Fisica Aplicada, Universidad de Extremadura, Merida, Badajoz, E-06800 (Spain); Loidl, M. [Laboratoire National Henri Becquerel, LNE/CEA-LIST, 91191 Gif-sur-Yvette (France); Coron, N.; Marcillac, P. de [Institut d' Astrophysique Spatiale, CNRS, 91405 Orsay Campus (France); Semkow, T.M. [Wadsworth Center, New York State Department of Health, Albany, NY 12201 (United States)

    2010-07-15

    Sources of enriched {sup 240}Pu were prepared by vacuum evaporation on quartz substrates. High-resolution alpha-particle spectrometry of {sup 240}Pu was performed with high statistical accuracy using silicon detectors and with low statistical accuracy using a bolometer. The alpha-particle emission probabilities of six transitions were derived from the spectra and compared with literature values. Additionally, some alpha-particle emission probabilities were derived from {gamma}-ray intensity measurements with a high-purity germanium detector. The alpha-particle emission probabilities of the three main transitions at 5168.1, 5123.6 and 5021.2 keV were derived from seven aggregate spectra analysed with five different fit functions and the results were compatible with evaluated data. Two additional weak peaks at 4863.5 and 4492.0 keV were fitted separately, using the exponential of a polynomial function to represent the underlying tailing of the larger peaks. The peak at 4655 keV could not be detected by alpha-particle spectrometry, while {gamma}-ray spectrometry confirms that its intensity is much lower than expected from literature.

  2. A synopsis of collective alpha effects and implications for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Sigmar, D.J.

    1990-10-01

    This paper discusses the following: Alpha Interaction with Toroidal Alfven Eigenmodes; Alpha Interaction with Ballooning Modes; Alpha Interaction with Fishbone Oscillations; and Implications for ITER.

  3. Infrared optical properties of $\\alpha$ quartz by molecular dynamics simulations

    CERN Document Server

    Gangemi, Fabrizio; Carati, Andrea; Maiocchi, Alberto; Galgani, Luigi

    2016-01-01

    This paper is concerned with theoretical estimates of the refractive--index curves for quartz, obtained by the Kubo formul\\ae\\ in the classical approximation, through MD simulations for the motions of the ions. Two objectives are considered. The first one is to understand the role of nonlinearities in situations where they are very large, as at the $\\alpha$--$\\beta$ structural phase transition. We show that on the one hand they don't play an essential role in connection with the form of the spectra in the infrared. On the other hand they play an essential role in introducing a chaoticity which involves a definite normal mode. This might explain why that mode is Raman active in the $\\alpha$ phase, but not in the $\\beta$ phase. The second objective concerns whether it is possible in a microscopic model to obtain normal mode frequencies, or peak frequencies in the optical spectra, that are in good agreement with the experimental data for quartz. Notwithstanding a lot of effort, we were unable to find results agr...

  4. The first spectra for the RX J0440.9+4431 from 2m Terskol telescope

    CERN Document Server

    Simon, Andrew; Reshetnyk, V M

    2012-01-01

    We present the first results on the spectra of Be/X-ray binary RX J0440.9+4431 obtained with the 2m Ritchey-Cretein-Coude telescope with Cassegrain Multi Mode Spectrograph (CMMS) (with R = 14000) at Terskol observatory. The H-alpha line profile indicates that the new episode of the V/R variability is occuring in the system. The profiles of the H-alpha, H-beta and HeI 7065.71, 6678.15, 5875.97 lines were analyzed and equivalent width were determined. We compared our H-alpha line profile parameters with the previous results from the literature and estimated characteristic time scale for disc changes as about 14 years.

  5. LYAPUNOV SPECTRA FOR KAPITZA OSCILLATOR

    Directory of Open Access Journals (Sweden)

    Nayyer Iqbal

    2012-02-01

    Full Text Available Here we purpose a simple but realistic model of one dimensional nonlinear Kapitza oscillator driven by sin- or cos- rapidly external oscillating periodical force. The model has a parameter 2gl=a22 of dimension one, depending on the amplitude a and frequency of modulation . Changing its value we construct phase portraits of the system in the neighbourhood of fixed points and demonstrate the changing in Lyapunov spectrum. Our purpose is to observe the behavior of system at fixed points due to the different structures of the Lyapunov spectra

  6. Rotational spectra and molecular structure

    CERN Document Server

    Wollrab, James E

    1967-01-01

    Physical Chemistry, A Series of Monographs: Rotational Spectra and Molecular Structure covers the energy levels and rotational transitions. This book is divided into nine chapters that evaluate the rigid asymmetric top molecules and the nuclear spin statistics for asymmetric tops. Some of the topics covered in the book are the asymmetric rotor functions; rotational transition intensities; classes of molecules; nuclear spin statistics for linear molecules and symmetric tops; and classical appearance of centrifugal and coriolis forces. Other chapters deal with the energy levels and effects of ce

  7. Identified hadron spectra from PHOBOS

    Science.gov (United States)

    Veres, Gábor I.; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wyslouch, B.; Zhang, J.

    2004-08-01

    Transverse momentum spectra of pions, kaons and protons, as well as antiparticle to particle ratios near mid-rapidity from d+Au collisions at \\sqrt{s_{{\\rm NN}}} = 200\\,{\\rm GeV} have been measured by the PHOBOS experiment at RHIC. The transverse momentum range of particle identification was extended to beyond 3 GeV/c using the TOF detector and a new trigger system. The pseudorapidity dependence of the nuclear modification factor for charged hadrons in d+Au collisions is presented.

  8. Satellite spectra of heliumlike nickel

    International Nuclear Information System (INIS)

    Spectra of heliumlike nickel, NiXXVII, have been observed from Tokamak Fusion Test Reactor (TFTR) plasmas with a high resolution crystal spectrometer. The experimental arrangement permits simultaneous observation of the heliumlike resonance line, the intercombination and forbidden lines, and all the associated satellites due to transitions 1s2nl - 1s2l'nl'' with N ≥ 2. Relative wavelengths and line intensities can thus be determined very accurately. The observed spectral data are in good agreement with results from the present Hartree-Fock-Slater atomic model calculations and predictions from the Z-expansion method

  9. How Is Alpha-1 Antitrypsin Deficiency Diagnosed?

    Science.gov (United States)

    ... Alpha-1 Antitrypsin Deficiency Diagnosed? Alpha-1 antitrypsin (AAT) deficiency usually is diagnosed after you develop a ... related to the condition. Your doctor may suspect AAT deficiency if you have signs or symptoms of ...

  10. How Is Alpha-1 Antitrypsin Deficiency Treated?

    Science.gov (United States)

    ... Alpha-1 Antitrypsin Deficiency Treated? Alpha-1 antitrypsin (AAT) deficiency has no cure, but its related lung ... pulmonary disease). If you have symptoms related to AAT deficiency, your doctor may recommend: Medicines called inhaled ...

  11. What Causes Alpha-1 Antitrypsin Deficiency?

    Science.gov (United States)

    ... this page from the NHLBI on Twitter. What Causes Alpha-1 Antitrypsin Deficiency? Alpha-1 antitrypsin (AAT) ... develop. The most common faulty gene that can cause AAT deficiency is called PiZ. If you inherit ...

  12. Calibration of sources for alpha spectroscopy systems

    International Nuclear Information System (INIS)

    This paper describes the calibration methodology for measuring the total alpha activity of plane and thin sources with the Alpha Spectrometer for Silicon Detector in the Nuclear Measures and Dosimetry laboratory at IEAv/CTA. (author)

  13. Monitor for alpha beta contamination of hands

    International Nuclear Information System (INIS)

    The following specifications of hands alpha beta contamination monitor are presented: the position of the hands, the detection and separation of alpha and beta, the information processing, the programming, the results presentation and general characteristics. (A.L.B.)

  14. \\alpha $ $^m $ Continuous Maps in Topological Spaces

    OpenAIRE

    Mathew, Milby; Parimelazhagan, R.; S Jafari

    2016-01-01

    The main aim of the present paper is to introduce new classes of functions called $ \\alpha $ $^m $ continuous maps and $ \\alpha $ $^m $ irresolute maps. We obtain some characterizations of these classes and properties are studied.

  15. A Detection Of H-alpha In An Exoplanetary Exosphere

    CERN Document Server

    Jensen, Adam G; Endl, Michael; Cochran, William D; Koesterke, Lars; Barman, Travis S

    2012-01-01

    We report on a search for H-alpha absorption in four exoplanets. Strong features at H-alpha are observed in the transmission spectra of both HD 189733b and HD 209458b. We attempt to characterize and remove the effects of stellar variability in HD 189733b, and along with an empirical Monte Carlo test the results imply a statistically significant transit-dependent feature of (-8.72+/-1.48)x10^-4 integrated over a 16 Angstrom band relative to the adjacent continuum. We interpret this as the first detection of this line in an exoplanetary atmosphere. A previous detection of Ly-alpha in HD 189733b's atmosphere allows us to calculate an excitation temperature for hydrogen, T_exc=2.6x10^4 K. This calculation depends significantly on certain simplifying assumptions. We explore these assumptions and argue that T_exc is very likely much greater than the radiative equilibrium temperature (the temperature the planet is assumed to be at based on stellar radiation and the planetary distance) of HD 189733b. A large T_exc im...

  16. Design and construction of a system for determining Radon-222 through Alpha spectroscopy

    International Nuclear Information System (INIS)

    The study of the present work consists on designing a system to measure gas 222 Rn, using a surface barrier detector, in order to obtaining a more accuracy measure of this isotope by means of an alpha particle spectra and thus to try to avoid the influence of the radioactivity of the isotope descendants of short half life, which are also emitting of alpha particles, since by other methods its should make a series of corrections to obtain the real value of the radon activity. (Author)

  17. Characterization of hydrogen interactions with the surface of alpha-2 titanium aluminide alloys

    Science.gov (United States)

    Shanabarger, Mickey R.

    1990-01-01

    The interaction of hydrogen at the surface of alpha-2 titanium aluminide alloys with Nb additions has been investigated with Auger electron spectroscopy (AES) and reflected electron energy loss (REELS) spectroscopy. The hydrogen was either adsorbed onto the alloy surface from the gas phase or it was pre-charged into the alloy forming an alpha-2 hydride. No effect of either adsorbed or absorbed hydrogen was observed in the Auger spectra. A shift in the bulk plasmon loss energy (observed with REELS) was measured for both conditions. The potential significance of these results in relation to hydrogen interactions in this alloy is discussed.

  18. Duality properties between spectra and tilings

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Spectra and tilings play an important role in analysis and geometry respectively.The relations between spectra and tilings have bafied the mathematicians for a long time.Many conjectures,such as the Fuglede conjecture,are placed on the establishment of relations between spectra and tilings,although there are no desired results.In the present paper we derive some characteristic properties of spectra and tilings which highlight certain duality properties between them.

  19. Operator functions and localization of spectra

    CERN Document Server

    Gil’, Michael I

    2003-01-01

    "Operator Functions and Localization of Spectra" is the first book that presents a systematic exposition of bounds for the spectra of various linear nonself-adjoint operators in a Hilbert space, having discrete and continuous spectra. In particular bounds for the spectra of integral, differential and integro-differential operators, as well as finite and infinite matrices are established. The volume also presents a systematic exposition of estimates for norms of operator-valued functions and their applications.

  20. Enzyme replacement therapy for alpha-mannosidosis

    DEFF Research Database (Denmark)

    Borgwardt, Line Gutte; Dali, Christine I.; Fogh, J;

    2013-01-01

    Alpha-mannosidosis (OMIM 248500) is a rare lysosomal storage disease (LSD) caused by alpha-mannosidase deficiency. Manifestations include intellectual disabilities, facial characteristics and hearing impairment. A recombinant human alpha-mannosidase (rhLAMAN) has been developed for weekly intrave...... intravenous enzyme replacement therapy (ERT). We present the preliminary data after 12 months of treatment....

  1. Fast computation of morphological area pattern spectra

    NARCIS (Netherlands)

    Meijster, Arnold; Wilkinson, Michael H.F.

    2001-01-01

    An area based counterpart of the binary structural opening spectra is developed It is shown that these area opening and closing spectra can be computed using an adaptation of Tarjan's union-find algorithm These spectra provide rotation, translation, and scale invariant pattern vectors for texture an

  2. Spectral Irradiance Calibration in the Infrared. Part 7; New Composite Spectra, Comparison with Model Atmospheres, and Far-Infrared Extrapolations

    Science.gov (United States)

    Cohen, Martin; Witteborn, Fred C.; Carbon, Duane F.; Davies, John K.; Wooden, Diane H.; Bregman, Jesse D.

    1996-01-01

    We present five new absolutely calibrated continuous stellar spectra constructed as far as possible from spectral fragments observed from the ground, the Kuiper Airborne Observatory (KAO), and the IRAS Low Resolution Spectrometer. These stars-alpha Boo, gamma Dra, alpha Cet, gamma Cru, and mu UMa-augment our six, published, absolutely calibrated spectra of K and early-M giants. All spectra have a common calibration pedigree. A revised composite for alpha Boo has been constructed from higher quality spectral fragments than our previously published one. The spectrum of gamma Dra was created in direct response to the needs of instruments aboard the Infrared Space Observatory (ISO); this star's location near the north ecliptic pole renders it highly visible throughout the mission. We compare all our low-resolution composite spectra with Kurucz model atmospheres and find good agreement in shape, with the obvious exception of the SiO fundamental, still lacking in current grids of model atmospheres. The CO fundamental seems slightly too deep in these models, but this could reflect our use of generic models with solar metal abundances rather than models specific to the metallicities of the individual stars. Angular diameters derived from these spectra and models are in excellent agreement with the best observed diameters. The ratio of our adopted Sirius and Vega models is vindicated by spectral observations. We compare IRAS fluxes predicted from our cool stellar spectra with those observed and conclude that, at 12 and 25 microns, flux densities measured by IRAS should be revised downwards by about 4.1% and 5.7%, respectively, for consistency with our absolute calibration. We have provided extrapolated continuum versions of these spectra to 300 microns, in direct support of ISO (PHT and LWS instruments). These spectra are consistent with IRAS flux densities at 60 and 100 microns.

  3. The Extreme Ultraviolet Spectra of Low Redshift Radio Loud Quasars

    CERN Document Server

    Punsly, Brian; Marziani, Paola; O'Dea, Christopher P

    2016-01-01

    This paper reports on the extreme ultraviolet (EUV) spectrum of three low redshift ($z \\sim 0.6$) radio loud quasars, 3C 95, 3C 57 and PKS 0405-123. The spectra were obtained with the Cosmic Origins Spectrograph (COS) of the Hubble Space Telescope. The bolometric thermal emission, $L_{bol}$, associated with the accretion flow is a large fraction of the Eddington limit for all of these sources. We estimate the long term time averaged jet power, $\\overline{Q}$, for the three sources. $\\overline{Q}/L_{bol}$, is shown to lie along the correlation of $\\overline{Q}/L_{bol}$ and $\\alpha_{EUV}$ found in previous studies of the EUV continuum of intermediate and high redshift quasars, where the EUV continuum flux density between 1100 \\AA\\, and 700 \\AA\\, is defined by $F_{\

  4. Power Density Spectra of $\\gamma$-Ray Bursts

    CERN Document Server

    Beloborodov, A M

    1999-01-01

    Power density spectra (PDSs) of long gamma-ray bursts provide useful information on GRBs, indicating their self-similar temporal structure. The best power-law PDSs are displayed by the longest bursts (T_90 > 100 s) in which the range of self-similar time scales covers more than 2 decades. Shorter bursts have apparent PDS slopes more strongly affected by statistical fluctuations. The underlying power law can then be reproduced with high accuracy by averaging the PDSs for a large sample of bursts. This power-law has a slope alpha\\approx -5/3 and a sharp break at 1 Hz. The power-law PDS provides a new sensitive tool for studies of gamma-ray bursts. In particular, we calculate the PDSs of bright bursts in separate energy channels. The PDS flattens in the hard channel (h\

  5. Monte Carlo nanodosimetry of alpha particle passages through the capillary endothelial nucleus application to systemic Targeted Alpha Therapy

    International Nuclear Information System (INIS)

    Full text: The biological effects of Targeted Alpha Therapy are strongly affected by the heterogeneous specific energy delivered to tumor cells. For systemic Targeted Alpha Therapy, all blood vessels inevitably received a background radiation from non-targeted decays with the blood circulation. The Geant4 Monte Carlo code was adapted to simulate the spatial non-uniform distribution of the alpha emitting radioisotope sources 213Bi, 212Bi and 211At. A cylindrical annulus was taken as a geometrical model to approximate the capillary. The endothelial cell nucleus was set to be an ellipsoid filled with liquid water to simulate nanometric target volumes at unit density. The Geant4 Low Energy physics model, based on the Livermore approach, was selected to model the particle interactions with the material in the experimental setup. The threshold of production of secondary particles was 7 eV. We validated the program with published results using spheroid cell geometry. The specific energy deposited in a capillary endothelial cell nucleus per radioactive decay and the capillary endothelial cell survival rates were calculated for the source constrained in the capillary lumen or the source binding to the surface antigen on the perivascular cancer cells. The measurement of nanodosimetric event size spectra based on simulated nanodosimetric data is presented. The value and limitations of this approach are discussed. (author)

  6. Damped Lyman-Alpha Galaxies

    CERN Document Server

    Turnshek, D A; Lane, W; Monier, E M; Nestor, D; Bergeron, J; Briggs, F; Smette, A

    2000-01-01

    Some results from an imaging program to identify low-redshift (0.09alpha (DLA) galaxies are presented. The standard paradigm that was widely accepted a decade ago, that DLA galaxies are the progenitors of luminous disk galaxies, is now being seriously challenged. The indisputable conclusion from imaging studies at low redshift is that the morphological types of DLA galaxies are mixed and that they span a range in luminosities and surface brightnesses.

  7. Diabetes and alpha lipoic acid

    OpenAIRE

    IssyLaher

    2011-01-01

    Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complicatio...

  8. Diabetes and Alpha Lipoic Acid

    OpenAIRE

    Golbidi, Saeid; Badran, Mohammad; Laher, Ismail

    2011-01-01

    Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complicatio...

  9. Analysis of multi-layer ERBS spectra

    Energy Technology Data Exchange (ETDEWEB)

    Marmitt, G.G. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Rosa, L.F.S. [Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Nandi, S.K. [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh); Vos, M., E-mail: maarten.vos@anu.edu.au [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia)

    2015-07-15

    Highlights: • Electron Rutherford backscattering (ERBS) spectra are presented. • The spectra are fitted based on physical meaningful quantities. • Very consistent results are obtained for spectra taken under different conditions. • This establishes that ERBS can be used to measure film thicknesses. - Abstract: A systematic way of analysis of multi-layer electron Rutherford backscattering spectra is described. The approach uses fitting in terms of physical meaningful parameters. Simultaneous analysis then becomes possible for spectra taken at different incoming energies and measurement geometries. Examples are given to demonstrate the level of detail that can be resolved by this technique.

  10. $Gamma(H\\to b\\bar{b})$ to order $\\alpha\\alpha_s$

    CERN Document Server

    Mihaila, Luminita; Steinhauser, Matthias

    2015-01-01

    We compute the decay rate of the Standard Model Higgs boson to bottom quarks to order $\\alpha\\alpha_s$. We apply the optical theorem and calculate the imaginary part of three-loop corrections to the Higgs boson propagator using asymptotic expansions in appropriately chosen mass ratios. The corrections of order $\\alpha\\alpha_s$ are of the same order of magnitude as the ${\\cal O}(\\alpha_s^3)$ QCD corrections but have the opposite sign.

  11. Alpha voltaic batteries and methods thereof

    Science.gov (United States)

    Raffaelle, Ryne P. (Inventor); Jenkins, Phillip (Inventor); Wilt, David (Inventor); Scheiman, David (Inventor); Chubb, Donald (Inventor); Castro, Stephanie (Inventor)

    2011-01-01

    An alpha voltaic battery includes at least one layer of a semiconductor material comprising at least one p/n junction, at least one absorption and conversion layer on the at least one layer of semiconductor layer, and at least one alpha particle emitter. The absorption and conversion layer prevents at least a portion of alpha particles from the alpha particle emitter from damaging the p/n junction in the layer of semiconductor material. The absorption and conversion layer also converts at least a portion of energy from the alpha particles into electron-hole pairs for collection by the one p/n junction in the layer of semiconductor material.

  12. Innovations in Los Alamos alpha box design

    International Nuclear Information System (INIS)

    Destructive examinations of irradiated fuel pins containing plutonium fuel must be performed in shielded hot cells with strict provisions for containing the plutonium. Alpha boxes provide containment for the plutonium, toxic fission products, and other hazardous highly radioactive materials. The alpha box contains windows for viewing and a variety of transfer systems specially designed to allow transfers in and out of the alpha box without spread of the hazardous materials that are contained in the box. Alpha boxes have been in use in the Wing 9 hot cells at Los Alamos National Laboratory for more than 20 years. Features of the newly designed alpha boxes are presented

  13. Innovations in Los Alamos alpha box design

    Energy Technology Data Exchange (ETDEWEB)

    Ledbetter, J.M.; Dowler, K.E.; Cook, J.H.

    1985-01-01

    Destructive examinations of irradiated fuel pins containing plutonium fuel must be performed in shielded hot cells with strict provisions for containing the plutonium. Alpha boxes provide containment for the plutonium, toxic fission products, and other hazardous highly radioactive materials. The alpha box contains windows for viewing and a variety of transfer systems specially designed to allow transfers in and out of the alpha box without spread of the hazardous materials that are contained in the box. Alpha boxes have been in use in the Wing 9 hot cells at Los Alamos National Laboratory for more than 20 years. Features of the newly designed alpha boxes are presented.

  14. Alpha particles detection in nitrocellulose

    International Nuclear Information System (INIS)

    The method for the manufacturing of the detection films follows these steps: preparation of the mass which includes nitrocellulose in the form of cotton as raw material ethyl acetate, cellosolve acetate, isopropyl and butyl alcohols as solvents and dioctyl phtalate as plasticiser; dilution of the paste; pouring of the diluted mass; and drying of the detection films. The results obtained experimentally are: The determination of the development times of the different thicknesses of the manufactured films. Response linearity of the detectors, variation of the number of tracks according to the distance of the source to the detector. Sizes of the diameter of the tracks depending of the distance detector-alpha emmission source. As a conclusion we can say the the nitrocellulose detectors are specific for alpha radiation; the more effective thicknesses in uranium prospecting works were those of 60 microns, since for the laboratory works the thicknesses of 30 to 40 microns were the ideal; the development technique of the detection films is simple and cheap and can be realized even in another place than the laboratory; this way of the manufacturing of nitrocellulose detection film sensitive to alpha nuclear radiation is open to future research. (author)

  15. Isotopic compositions of terrestrial thorium: a search in terrestrial thorium for the unidentified excess 4.6 MeV alpha-activity of lunar thorium

    International Nuclear Information System (INIS)

    Since thorium in lunar crystalline rocks was reported to be excessive in 4.6 MeV alpha-activity up to 80%, which was attributed to a long-lived isomer of 232Th with an origin different from normal thorium, alpha-spectra of various terrestrial thorium were measured in order to see if terrestrial thorium also contains some excess 4.6 MeV alpha-activity. The results showed that the content of the excess 4.6 MeV alpha-activity in terrestrial thorium, if any, is much less than 3%. An approach to set an upper limit for the excess alpha-activity in terrestrial thorium is proposed. The origin of the excess alpha-activity is discussed. (author) 21 refs.; 3 tabs

  16. Chemical vapor deposition (CVD) of uranium for alpha spectrometry

    International Nuclear Information System (INIS)

    The uranium determination through radiometric techniques as alpha spectrometry requires for its proper analysis, preparation methods of the source to analyze and procedures for the deposit of this on a surface or substrate. Given the characteristics of alpha particles (small penetration distance and great loss of energy during their journey or its interaction with the matter), is important to ensure that the prepared sources are thin, to avoid problems of self-absorption. The routine methods used for this are the cathodic electro deposition and the direct evaporation, among others. In this paper the use of technique of chemical vapor deposition (CVD) for the preparation of uranium sources is investigated; because by this, is possible to obtain thin films (much thinner than those resulting from electro deposition or evaporation) on a substrate and comprises reacting a precursor with a gas, which in turn serves as a carrier of the reaction products to achieve deposition. Preliminary results of the chemical vapor deposition of uranium are presented, synthesizing and using as precursor molecule the uranyl acetylacetonate, using oxygen as carrier gas for the deposition reaction on a glass substrate. The uranium films obtained were found suitable for alpha spectrometry. The variables taken into account were the precursor sublimation temperatures and deposition temperature, the reaction time and the type and flow of carrier gas. Of the investigated conditions, two depositions with encouraging results that can serve as reference for further work to improve the technique presented here were selected. Alpha spectra obtained for these depositions and the characterization of the representative samples by scanning electron microscopy and X-ray diffraction are also presented. (Author)

  17. Different spectra with the same neutron source

    International Nuclear Information System (INIS)

    Using as source term the spectrum of a 239Pu-Be source several neutron spectra have been calculated using Monte Carlo methods. The source term was located in the centre of spherical moderators made of light water, heavy water and polyethylene of different diameters. Also a 239Pu-Be source was used to measure its neutron spectrum, bare and moderated by water. The neutron spectra were measured at 100 cm with a Bonner spheres spectrometer. Monte Carlo calculations were used to calculate the neutron spectra of bare and water-moderated spectra that were compared with those measured with the spectrometer. Resulting spectra are similar to those found in power plants with PWR, BWR and Candu nuclear reactors. Beside the spectra the dosimetric features were determined. Using moderators and a single neutron source can be produced neutron spectra alike those found in workplaces, this neutron fields can be utilized to calibrate neutron dosimeters and area monitors. (Author)

  18. Optimal Extraction of Echelle Spectra

    Science.gov (United States)

    Piskunov, Nikolai

    The extraction of the echelle spectra registered with a CCD detector represents a big challenge because of three reasons: (1) the pixel sampling is often close or worse then optimal, (2) spectral orders are curved and tilted with respect to the CCD rows (or columns) and (3) every pixel contains additional noise coming from various sources as illustrated in Figure 1. The main goal of an optimal extraction is to recover as much of the science signal while minimizing the contribution of the noise. Here we present the Slit Function Decomposition algorithm which replaces the summation in a sliding window with a reconstruction of the slit illumination profile. The reconstruction is formulated as an inverse problem solved by iterations and it is robust against most of the systematic problems including cosmic rays and cosmetic defects.

  19. Quantum entanglement without eigenvalue spectra

    CERN Document Server

    Chen, H

    2001-01-01

    We introduce algebraic sets in complex projective spaces for the mixed states in bipartite quantum systems, which are independent of their eigenvalues and only measure the "position" of their eigenvectors, as their nonlocal invariants (ie., remaining invariant after local unitary transformations). The algebraic sets have to be the union of the linear subspaces if the mixed state is separable, and thus we give a "eigenvalue-free" criterion of separability. Based on our criterion, examples are given to illustrate that entangled mixed states which are invariant under partial transposition or fufill entropy and disorder criterion of separability can be constructed systematically. A by-product is a interesting lower bound of the Schmidt numbers of the "random" rank m mixed states in mxm sysytems. We reveal that a large part of quantum entanglement is independent of eigenvalue spectra and develop a method to measure this part of quantum enatnglement.

  20. Geant4 simulations for sedimentary grains in infinite matrix conditions: The case of alpha dosimetry

    International Nuclear Information System (INIS)

    Simulations based on the Geant4 toolkit have been performed in order to reproduce the electromagnetic interactions of alpha particles in a spherical grain embedded in an infinite radioactive matrix and to assess several dosimetric parameters; updated alpha attenuation factors have thus been calculated for a clay matrix. Their sensitivity to the chemical composition of both the coating matrix and the grain, as well as to the water content of the matrix, has also been investigated. Finally, differences between the energetic spectrum of the incident alpha particles and the deposited energy spectrum in the grain have been highlighted for fine and coarse grains, and their impact in terms of alpha dosimetry has been discussed. - Highlights: • We simulate sedimentary grains in an infinite matrix and alpha particles flux. • The dose deposited and the energetic spectra in the grain are studied. • Attenuation factors are calculated for several grain sizes and matrix compositions. • Grain size in regard of alpha range has to be considered for efficiency calculation

  1. A Correlation Between Ly{\\alpha} Spectral Line Profile and Rest-Frame UV Morphology

    CERN Document Server

    U, Vivian; Darvish, Behnam; Mobasher, Bahram; Nayyeri, Hooshang; Dickinson, Mark; Stern, Daniel; Spinrad, Hyron; Mallery, Ryan

    2015-01-01

    We explore the relationship between the spectral shape of the Ly{\\alpha} emission and the UV morphology of the host galaxy using a sample of 304 Ly{\\alpha}-emitting BV i-dropouts at 3 < z < 7 in the GOODS and COSMOS fields. Using our extensive reservoir of high-quality Keck DEIMOS spectra combined with HST WFC3 data, we measure the Ly{\\alpha} line asymmetries for individual galaxies and compare them to axial ratios measured from observed J- and H-band (restframe UV) images. We find that the Ly{\\alpha} skewness exhibits a large scatter at small elongation (a/b < 2), and this scatter decreases as axial ratio increases. Comparison of this trend to radiative transfer models and various results from literature suggests that these high-redshift Ly{\\alpha} emitters are not likely to be intrinsically round and symmetric disks, but they probably host galactic outflows traced by Ly{\\alpha} emitting clouds. The ionizing sources are centrally located, with the optical depth a good indicator of the absorption and...

  2. Extracting H$\\alpha$ flux from photometric data in the J-PLUS survey

    CERN Document Server

    Vilella-Rojo, G; López-Sanjuan, C; Cenarro, A J; Varela, J; Díaz-García, L A; Cristóbal-Hornillos, D; Ederoclite, A; Marín-Franch, A; Moles, M

    2015-01-01

    We present the main steps that will be taken to extract H$\\alpha$ emission flux from Javalambre Photometric Local Universe Survey (J-PLUS) photometric data. For galaxies with $z\\lesssim0.015$, the H$\\alpha$+[NII] emission is covered by the J-PLUS narrow-band filter $F660$. We explore three different methods to extract the H$\\alpha$ + [NII] flux from J-PLUS photometric data: a combination of a broad-band and a narrow-band filter ($r'$ and $F660$), two broad-band and a narrow-band one ($r'$, $i'$ and $F660$), and a SED-fitting based method using 8 photometric points. To test these methodologies, we simulated J-PLUS data from a sample of 7511 SDSS spectra with measured H$\\alpha$ flux. Based on the same sample, we derive two empirical relations to correct the derived H$\\alpha$+[NII] flux from dust extinction and [NII] contamination. We find that the only unbiased method is the SED fitting based one. The combination of two filters underestimates the measurements of the H$\\alpha$ + [NII] flux by a 28%, while the th...

  3. Measurements of lineal energy spectra for the BNCT test beam of THOR

    International Nuclear Information System (INIS)

    A 2.5 cm tissue-equivalent Rossi type proportional counter was fabricated at St Andrews University and used in this study. Boron-doped and non-boron chambers were performed to measure the lineal energy spectra of a test epithermal neutron beam, built for the research of boron neutron capture therapy (BNCT) at Tsing Hua Open-pool Reactor (THOR). Measurements were made using standard microdosimetry equipment, including a low pressure gas flow system, low noise charge sensitive preamplifier, linear amplifier, multi-channel analyzer, and americium-241 calibration alpha source. Chambers were positioned at different depths in an acrylic phantom. Lineal energy spectra were determined for several gas pressures to simulate various cell sizes. Spectra of the boron-doped chamber are dominated by a peak at ∼200 keV/μm corresponding to the traversal of alpha particles and lithium recoils through the chamber. Peaks in the non-boron spectra correspond to gamma-rays, recoil protons, and fast neutrons. (author)

  4. What causes the Ly-alpha forest, clouds or large-scale velocity fields ?

    OpenAIRE

    Kegel, W. H.; Levshakov, S. A.

    1997-01-01

    We show that in stochastic large scale velocity fields superposed on the general Hubble flow, the formation of the GP-depression in QSO spectra is intimately related to the formation of the absorption-line structure usually called `Ly-alpha forest'. Therefore the HI-density in the diffuse IGM might be substaintially underestimated if one determines the GP-effect from the apparent continuum in high resolution spectra of QSOs. Our tentative calculations imply a current baryon density Omega_b h^...

  5. What causes the Ly$\\alpha$ forest, clouds or large-scale velocity fields ?

    CERN Document Server

    Kegel, W H

    1997-01-01

    We show that in stochastic large scale velocity fields superposed on the general Hubble flow, the formation of the GP-depression in QSO spectra is intimately related to the formation of the absorption-line structure usually called `Ly-alpha forest'. Therefore the HI-density in the diffuse IGM might be substaintially underestimated if one determines the GP-effect from the apparent continuum in high resolution spectra of QSOs. Our tentative calculations imply a current baryon density Omega_b h^2_{100} = 0.015 which agrees well with the baryon density determination from the deuterium abaundance measurement by Levshakov, Kegel and Takahara (the same volume).

  6. Cutoff in the Lyman {\\alpha} forest power spectrum: warm IGM or warm dark matter?

    CERN Document Server

    Garzilli, Antonella; Ruchayskiy, Oleg

    2015-01-01

    We re-analyse high redshift and high resolution Lyman-{\\alpha} forest spectra from Viel et al. [1] seeking to constrain properties of warm dark matter particles. Compared to the previous work we consider a wider range on thermal histories of the intergalactic medium and find that both warm and cold dark matter models can explain the cut-off observed in the flux power spectra of high-resolution observations equally well. This implies, however, very different thermal histories and underlying re-ionisation models. We discuss how to remove this degeneracy.

  7. Identification of noncollagenous sites encoding specific interactions and quaternary assembly of alpha 3 alpha 4 alpha 5(IV) collagen: implications for Alport gene therapy.

    Science.gov (United States)

    Kang, Jeong Suk; Colon, Selene; Hellmark, Thomas; Sado, Yoshikazu; Hudson, Billy G; Borza, Dorin-Bogdan

    2008-12-12

    Defective assembly of alpha 3 alpha 4 alpha 5(IV) collagen in the glomerular basement membrane causes Alport syndrome, a hereditary glomerulonephritis progressing to end-stage kidney failure. Assembly of collagen IV chains into heterotrimeric molecules and networks is driven by their noncollagenous (NC1) domains, but the sites encoding the specificity of these interactions are not known. To identify the sites directing quaternary assembly of alpha 3 alpha 4 alpha 5(IV) collagen, correctly folded NC1 chimeras were produced, and their interactions with other NC1 monomers were evaluated. All alpha1/alpha 5 chimeras containing alpha 5 NC1 residues 188-227 replicated the ability of alpha 5 NC1 to bind to alpha3NC1 and co-assemble into NC1 hexamers. Conversely, substitution of alpha 5 NC1 residues 188-227 by alpha1NC1 abolished these quaternary interactions. The amino-terminal 58 residues of alpha3NC1 encoded binding to alpha 5 NC1, but this interaction was not sufficient for hexamer co-assembly. Because alpha 5 NC1 residues 188-227 are necessary and sufficient for assembly into alpha 3 alpha 4 alpha 5 NC1 hexamers, whereas the immunodominant alloantigenic sites of alpha 5 NC1 do not encode specific quaternary interactions, the findings provide a basis for the rational design of less immunogenic alpha 5(IV) collagen constructs for the gene therapy of X-linked Alport patients. PMID:18930919

  8. Analysis of the Lyman-$\\alpha$ Forest in Cosmological Simulations Using Voigt-Profile Decomposition

    CERN Document Server

    Davé, R; Weinberg, D H; Katz, N; Davé, Romeel; Hernquist, Lars; Weinberg, David H.; Katz, Neal

    1996-01-01

    We use an automated Voigt-profile fitting procedure to extract statistical properties of the Ly$\\alpha$ forest in a numerical simulation of an $\\Omega=1$, cold dark matter (CDM) universe. Our analysis method is similar to that used in most observational studies of the forest, and we compare the simulations to recently published results derived from Keck HIRES spectra. With the Voigt-profile decomposition analysis, the simulation reproduces the large number of weak lines ($N_{\\rm HI}\\la 10^{14} cm^{-2}$) found in the HIRES spectra. At $z=3$, the $b$-parameter distribution has a median of $35\\kms$ and a dispersion of $20\\kms$, in reasonable agreement with the observed values. The comparison between our new analysis and recent data strengthens earlier claims that the Ly$alpha$ forest arises naturally in hierarchical structure formation as photoionized gas falls into dark matter potential wells.

  9. $\\alpha_s$ extractions from CMS (status and plans)

    CERN Document Server

    Rabbertz, Klaus

    2015-01-01

    Numerous extractions of the strong coupling constant have been performed at hadron colliders, in particular from jet cross sections. The latest results achieved by the experiments at the $ep$ collider HERA, at the $p\\bar{p}$ collider Tevatron, and at the $pp$ collider LHC are reported with emphasis on the CMS experiment for the latter. Future prospects for precision determinations of $\\alpha_s(M_Z)$ and for testing the running of the strong coupling beyond the TeV range are discussed.

  10. Constraining the temperature-density relation of the intergalactic medium with the Lyman-$\\alpha$ and $\\beta$ forests

    CERN Document Server

    Boera, Elisa; Becker, George D; Bolton, James S

    2015-01-01

    The post-reionization thermal state of the intergalactic medium is characterized by a power-law relationship between temperature and density, with a slope determined by the parameter $\\gamma$. We describe a new method to measure $\\gamma$ using the ratio of flux curvature in the Lyman-$\\alpha$ and $\\beta$ forests. At a given redshift, this curvature ratio incorporates information from the different gas densities traced by Lyman-$\\alpha$ and $\\beta$ absorption. It is relatively simple and fast to compute and appears robust against several observational uncertainties. We apply this technique to a sample of 27 high-resolution quasar spectra from the Very Large Telescope. While promising statistical errors on $\\gamma$ appear to be achievable with these spectra, to reach its full potential, the dependence of the curvature ratio on the thermal state of the gas in the foreground Lyman-$\\alpha$ forest will require further, detailed forward modelling.

  11. Pulsed Cathodoluminescence Spectra of Solid Oxides with Low Concentrations of Optically-Active Impurities

    CERN Document Server

    Kozlov, V A; Pestovskii, N V; Petrov, A A; Savinov, S Yu; Zavartsev, Yu D; Zavertyaev, M V; Zagumenniy, A I

    2016-01-01

    Pulsed cathodoluminescence (PCL) spectra of ultra-pure SiO2, GeO2, SnO2, TiO2, La2O3, Y2O3, Sc2O3, CaCO3 powders and {\\alpha}-quartz, Ca:YVO4, LiNbO3 and Sc:LiNbO3 crystals were studied under the same experimental conditions. It was found that PCL spectra of SiO2, SnO2, GeO2, TiO2, La2O3 and CaCO3 powders contain a common band with maximum intensity at 500 nm, PCL spectra of samples Y2O3, Sc2O3, PbWO4 and Ca:YVO4 contain a common band at 490 nm and PCL spectra of LiNbO3 and Sc:LiNbO3 crystals contain a common band at 507 nm. It was found that the average intensity of the PCL spectra and position of the maximum intensity of these common bands depend on the type of a band gap transition of the material. We suppose that these common bands have the same origin in PCL spectra of all the materials studied and are related to recombination of O2--O-oxygen complexes. These complexes appear in the vicinities of anionic and cationic vacancies, where the geometry and orientation of coordination polyhedrons are violated d...

  12. HH 666: Different kinematics from H{\\alpha} and [Fe II] emission provide a missing link between jets and outflows

    CERN Document Server

    Reiter, Megan; Kiminki, Megan M; Bally, John

    2015-01-01

    HH 666 is an externally irradiated protostellar outflow in the Carina Nebula for which we present new near-IR [Fe II] spectra obtained with the FIRE spectrograph at Magellan Observatory. Earlier H{\\alpha} and near-IR [Fe II] imaging revealed that the two emission lines trace substantially different morphologies in the inner ~40" of the outflow. H{\\alpha} traces a broad cocoon that surrounds the collimated [Fe II] jet that extends throughout the parent dust pillar. New spectra show that this discrepancy extends to their kinematics. Near-IR [Fe II] emission traces steady, fast velocities of +/- 200 km/s from the eastern and western limbs of the jet. We compare this to a previously published H{\\alpha} spectrum that reveals a Hubble-flow velocity structure near the jet-driving source. New, second-epoch HST/ACS H{\\alpha} images reveal the lateral spreading of the H{\\alpha} outflow lobe away from the jet axis. H{\\alpha} proper motions also indicate a sudden increase in the mass-loss rate ~1000 yr ago, while steady ...

  13. Folding model study of the elastic $\\alpha + \\alpha$ scattering at low energies

    CERN Document Server

    Tan, Ngo Hai; Khoa, Dao T

    2014-01-01

    The folding model analysis of the elastic $\\alpha + \\alpha$ scattering at the incident energies below the reaction threshold of 34.7 MeV (in the lab system) has been done using the well-tested density dependent versions of the M3Y interaction and realistic choices for the $^4$He density. Because the absorption is negligible at the energies below the reaction threshold, we were able to probe the $\\alpha + \\alpha$ optical potential at low energies quite unambiguously and found that the $\\alpha + \\alpha$ overlap density used to construct the density dependence of the M3Y interaction is strongly distorted by the Pauli blocking. This result gives possible explanation of a long-standing inconsistency of the double-folding model in its study of the elastic $\\alpha + \\alpha$ and $\\alpha$-nucleus scattering at low energies using the same realistic density dependent M3Y interaction.

  14. The 2009 Wolrd Average of $\\alpha_s (M_Z)$

    CERN Document Server

    Bethke, Siegfried

    2009-01-01

    Measurements of $\\alpha_s$, the coupling strength of the Strong Interaction between quarks and gluons, are summarised and an updated value of the world average of $\\alpha_s (M_Z)$ is derived. Building up on previous reviews, special emphasis is laid on the most recent determinations of $\\alpha_s$. These are obtained from $\\tau$-decays, from global fits of electroweak precision data and from measurements of the proton structure function $\\F_2$, which are based on perturbative QCD calculations up to $O(\\alpha_s^4)$; from hadronic event shapes and jet production in $\\epem$ annihilation, based on $O(\\alpha_s^3) $ QCD; from jet production in deep inelastic scattering and from $\\Upsilon$ decays, based on $O(\\alpha_s^2) $ QCD; and from heavy quarkonia based on unquenched QCD lattice calculations. Applying pragmatic methods to deal with possibly underestimated errors and/or unknown correlations, the world average value of $\\alpha_s (M_Z)$ results in $\\alpha_s (M_Z) = 0.1184 \\pm 0.0007$. The measured values of $\\alpha...

  15. Study of giant resonances at high excitation energy by alpha inelastic scattering

    International Nuclear Information System (INIS)

    Angular distributions of 340 and 480 MeV alpha particles inelastically scattered by 208Pb, 116Sn and 58Ni up to 60 MeV of excitation have been measured. The experimental inelastic spectra have been analysed by means of a new global method. The repartition of multipole strength shows the already known low energy giant resonances into more details. New high energy giant resonances are observed

  16. The alpha magnetic spectrometer silicon tracker: Performance results with protons and helium nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, J. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas (CIEMAT), E-28040 Madrid (Spain); Alpat, B.; Ambrosi, G. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Azzarello, Ph. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland); Battiston, R.; Bertucci, B. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Bolmont, J. [Laboratoire de Physique Theorique et Astroparticules, IN2P3/CNRS, Universite de Montpellier II, F-34095 Montpellier (France); Bourquin, M. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland); Burger, W.J. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy)], E-mail: william.burger@cern.ch; Capell, M. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cardano, F. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Chang, Y.H. [National Central University, Jhungli 320, Taiwan (China); Choutko, V. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Cortina, E. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland); Dinu, N. [Institute for Space Science (ISS), R-76900 Bucharest (Romania); Esposito, G.; Fiandrini, E. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Haas, D. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland); Haino, S. [INFN Sezione di Perugia and Universita degli Studi di Perugia, I-06100 Perugia (Italy); Hakobyan, H. [Universite de Geneve, CH-1211, Geneve 4 (Switzerland)] (and others)

    2008-08-11

    The Alpha Magnetic Spectrometer is designed for a long duration measurement of the cosmic-ray spectra at an altitude of 400 km. The particle rigidity and specific energy loss are measured by a silicon tracker located in a 0.8 T field. Ground results for the position resolution, detection efficiency and charge determination for singly and doubly charged relativistic particles are presented and discussed in the context of the spaceborne detector.

  17. The alpha magnetic spectrometer silicon tracker: Performance results with protons and helium nuclei

    International Nuclear Information System (INIS)

    The Alpha Magnetic Spectrometer is designed for a long duration measurement of the cosmic-ray spectra at an altitude of 400 km. The particle rigidity and specific energy loss are measured by a silicon tracker located in a 0.8 T field. Ground results for the position resolution, detection efficiency and charge determination for singly and doubly charged relativistic particles are presented and discussed in the context of the spaceborne detector

  18. Downstream energetic proton and alpha particles during quasi-parallel interplanetary shock events

    Science.gov (United States)

    Tan, L. C.; Mason, G. M.; Gloeckler, G.; Ipavich, F. M.

    1988-01-01

    This paper considers the energetic particle populations in the downstream region of three quasi-parallel interplanetary shock events, which was explored using the ISEE 3 Ultra Low Energy Charge Analyzer sensor, which unambiguously identifies protons and alpha particles using the electrostatic deflection versus residual energy technique. The downstream particles were found to exhibit anisotropies due largely to convection in the solar wind. The spectral indices of the proton and the alpha-particle distribution functions were found to be remarkably constant during the downstream period, being generally insensitive to changes in particle flux levels, magnetic field direction, and solar wind densities. In two of the three events, the proton and the alpha spectra were the same throughout the entire downstream period, supporting the prediction of diffusive shock acceleration theory.

  19. Alpha spectrometric ionization chamber with 2 m2 working area and its application

    International Nuclear Information System (INIS)

    A grid ionization chamber with cylindrical configuration was constructed for the measurement of the alpha spectra of very low level samples, which makes possible the measurement of radiation sources with an area of up to 2 m2. The chamber has a volume of 400 l and is filled with technical argon with 5% addition of methane. Energy resolution of the detection system is 85 keV at 5.5 MeV, detection efficiency is 37% and the background at a range of 200 keV at 5.5 MeV is 10 cph. The detection limit is 1 mBq. The chamber may be used for measuring half-life of alpha-emitting rare earths, for dating sediments using the 210Pb-210Po method and geological samples using the U-Th method, for determining the composition and concentration of natural and technogenic alpha sources in natural samples. (J.P.)

  20. STIS Observations of the Low-z Ly-Alpha Forest

    Science.gov (United States)

    Heap, Sara R.; Weymann, Ray; Williger, Gerry; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope has brought a new era in studying the low-redshift Lyman-alpha Forest. The advantages of STIS over previous HST spectrographs include: (1) a high spectral resolution (7 km/s) comparable to Keck/HIRES spectra of the high-z Lyman-alpha forest; and (2) a high observing efficiency brought about by an imaging detector able to span the full far-UV wavelength range (1150-1700 A, or equivalently, z=0.0-0.4) in a single exposure. The STIS Investigation Definition Team is therefore conducting an observational program to determine the properties of the low-z intergalactic medium as manifested by the Lyman-alpha forest. The team has made observations of the quasars: 3C 273, 3C 351, and PKS 0405. We shall present preliminary results based on the sightline to 3C 273, the brightest of these sources.

  1. HST/STIS Spectroscopy of the Local Lyman-Alpha Forest

    Science.gov (United States)

    Heap, Sara R.; Dave, R. A.; Weymann, R.; Williger, G.; Jenkins, E.; Tripp, T.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    The Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope has brought a new era in studying the low-redshift Lyman-alpha Forest. The advantages of STIS over previous HST spectrographs include:(l) a high spectral resolution (7 km/s) comparable to Keck/HIRES spectra of the high-redshift Lyman-alpha forest; (2) a high observing efficiency brought about by an imaging detector able to span the full fares wavelength range (1150-1700 A, or equivalently, z=0.0-0.4) in a single exposure. The STIS Investigation Definition Team is therefore conducting an observational program to determine the properties of the low-redshift intergalactic medium as manifested by the Lyman-alpha forest. The team has made observations of the quasars: 3C 273, 3C 351, and PKS 0405. We shall present results based on the sightline to 3C 273, the brightest of these sources.

  2. Blind extraction of exoplanetary spectra

    Science.gov (United States)

    Morello, Giuseppe; Waldmann, Ingo P.; Tinetti, Giovanna

    2016-06-01

    In the last decade, remote sensing spectroscopy enabled characterization of the atmospheres of extrasolar planets. Transmission and emission spectra of tens of transiting exoplanets have been measured with multiple instruments aboard Spitzer and Hubble Space Telescopes as well as ground-based facilities, revealing the presence of atomic, ionic and molecular species in their atmospheres, and constraining their temperature and pressure profiles.Early analyses were somehow heuristic both in measuring the spectra and in their interpretation, leading to some controversies in the literature.A photometric precision of 0.01% is necessary to detect the atmospheric spectral modulations. Current observatories, except Kepler, were not designed to achieve this precision. Data reduction is necessary to minimize the effect of instrument systematics in order to achieve the target precision. In the past, parametric models have extensively been used by most teams to remove correlated noise with the aid of auxiliary information of the instrument, the so-called optical state vectors (OSVs). Such OSVs can include inter- and intra-pixel position of the star or its spectrum, instrument temperatures and inclinations, and/or other parameters. In some cases, different parameterizations led to discrepant results.We recommend the use of blind non-parametric data detrending techniques to overcome those issues. In particular, we adopt Independent Component Analysis (ICA), i.e. a blind source separation (BSS) technique to disentangle the multiple instrument systematics and astrophysical signals in transit/eclipse light curves. ICA does not require a model for the systematics, and for this reason, it can be applied to any instrument with little changes, if any. ICA-based algorithms have been applied to Spitzer/IRAC and synthetic observations in photometry (Morello et al. 2014, 2015, 2016; Morello 2015) and to Hubble/NICMOS and Spitzer/IRS in spectroscopy (Waldmann 2012, 2014, Waldmann et al. 2013

  3. Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in the reaction Ca-48 + Am-243

    CERN Document Server

    Forsberg, U; Andersson, L -L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Golubev, P; Gregorich, K E; Gross, C J; Herzberg, R -D; Hessberger, F P; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Sarmiento, L G; Schädel, M; Yakushev, A; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Dobaczewski, J; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nazarewicz, W; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Shi, Y; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

    2015-01-01

    Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum f\\"ur Schwerionenforschung. Amongst the detected thirty correlated alpha-decay chains associated with the production of element Z=115, two recoil-alpha-fission and five recoil-alpha-alpha-fission events were observed. The latter are similar to four such events reported from experiments performed at the Dubna gas-filled separator. Contrary to their interpretation, we propose an alternative view, namely to assign eight of these eleven decay chains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation channel 115-288. The other three decay chains remain viable candidates for the 2n-evaporation channel 115-289.

  4. A catalogue of early-type emission-line stars and H{\\alpha} line profiles from LAMOST DR2

    CERN Document Server

    Hou, Wen; Hu, Jingyao; Yang, Haifeng; Du, Changde; Liu, Chao; Lee, Chien-De; Lin, Chien-Cheng; Wang, Yuefei; Zhang, Yong; Cao, Zihuang; Hou, Yonghui

    2016-01-01

    We present a catalogue including 11,204 spectra for 10,436 early-type emission-line stars from LAMOST DR2, among which 9,752 early-type emission-line spectra are newly discovered. For these early-type emission-line stars, we discuss the morphological and physical properties from their low-resolution spectra. In this spectral sample, the H$\\alpha$ emission profiles display a wide variety of shapes. Based on the H$\\alpha$ line profiles, these spectra are categorized into five distinct classes: single-peak emission, single-peak emission in absorption, double-peak emission, double-peak emission in absorption, and P-Cygni profiles. To better understand what causes the H$\\alpha$ line profiles, we divide these objects into four types from the view of physical classification, which include classical Be stars, Herbig Ae/Be stars, close binaries and spectra contaminated by HII regions. The majority of Herbig Ae/Be stars and classical Be stars are identified and separated using the (H-K, K-W1) color-color diagram. We al...

  5. Study of the shape of β spectra

    International Nuclear Information System (INIS)

    The goal of this PhD work is to build an experimental device dedicated to measuring beta spectra with a precision relevant to modern metrology requirements. The device, which is based on a silicon semi-conductor detector, must take into account certain physical phenomena and detector characteristics which could lead to deformation of the measured spectra. These must be understood and minimized. Monte-Carlo simulations have allowed the geometry and construction materials to be optimized. The quality of the radioactive sources is paramount in obtaining spectra of high-quality. Nonetheless, the measured spectra must be corrected for any remaining distortion. A response function must therefore be determined for each measurement geometry. This can be achieved via Monte-Carlo simulations. The first results show that deconvolution of the measured spectra with the response function makes possible the accurate determination of the true form of the beta spectra. (author)

  6. Targeted alpha therapy for cancer

    Science.gov (United States)

    Allen, Barry J.; Raja, Chand; Rizvi, Syed; Li, Yong; Tsui, Wendy; Zhang, David; Song, Emma; Qu, Chang Fa; Kearsley, John; Graham, Peter; Thompson, John

    2004-08-01

    Targeted alpha therapy (TAT) offers the potential to inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The practicality and efficacy of TAT is tested by in vitro and in vivo studies in melanoma, leukaemia, colorectal, breast and prostate cancers, and by a phase 1 trial of intralesional TAT for melanoma. The alpha-emitting radioisotope used is Bi-213, which is eluted from the Ac-225 generator and chelated to a cancer specific monoclonal antibody (mab) or protein (e.g. plasminogen activator inhibitor-2 PAI2) to form the alpha-conjugate (AC). Stable alpha-ACs have been produced which have been tested for specificity and cytotoxicity in vitro against melanoma (9.2.27 mab), leukaemia (WM60), colorectal (C30.6), breast (PAI2, herceptin), ovarian (PAI2, herceptin, C595), prostate (PAI2, J591) and pancreatic (PAI2, C595) cancers. Subcutaneous inoculation of 1-1.5 million human cancer cells into the flanks of nude mice causes tumours to grow in all mice. Tumour growth is compared for untreated controls, nonspecific AC and specific AC, for local (subcutaneous) and systemic (tail vein or intraperitoneal) injection models. The 213Bi-9.2.27 AC is injected into secondary skin melanomas in stage 4 patients in a dose escalation study to determine the effective tolerance dose, and to measure kinematics to obtain the equivalent dose to organs. In vitro studies show that TAT is one to two orders of magnitude more cytotoxic to targeted cells than non-specific ACs, specific beta emitting conjugates or free isotopes. In vivo local TAT at 2 days post-inoculation completely prevents tumour formation for all cancers tested so far. Intra-lesional TAT can completely regress advanced sc melanoma but is less successful for breast and prostate cancers. Systemic TAT inhibits the growth of sc melanoma xenografts and gives almost complete control of breast and prostate cancer tumour growth. Intralesional doses up to 450 µCi in human

  7. The Alpha Magnetic Spectrometer (AMS)

    CERN Document Server

    Alcaraz, J; Ambrosi, G; Anderhub, H; Ao, L; Arefev, A; Azzarello, P; Babucci, E; Baldini, L; Basile, M; Barancourt, D; Barão, F; Barbier, G; Barreira, G; Battiston, R; Becker, R; Becker, U; Bellagamba, L; Bene, P; Berdugo, J; Berges, P; Bertucci, B; Biland, A; Bizzaglia, S; Blasko, S; Bölla, G; Boschini, M; Bourquin, Maurice; Brocco, L; Bruni, G; Buénerd, M; Burger, J D; Burger, W J; Cai, X D; Camps, C; Cannarsa, P; Capell, M; Casadei, D; Casaus, J; Castellini, G; Cecchi, C; Chang, Y H; Chen, H F; Chen, H S; Chen, Z G; Chernoplekov, N A; Tzi Hong Chiueh; Chuang, Y L; Cindolo, F; Commichau, V; Contin, A; Crespo, P; Cristinziani, M; Cunha, J P D; Dai, T S; Deus, J D; Dinu, N; Djambazov, L; Dantone, I; Dong, Z R; Emonet, P; Engelberg, J; Eppling, F J; Eronen, T; Esposito, G; Extermann, P; Favier, Jean; Fiandrini, E; Fisher, P H; Flügge, G; Fouque, N; Galaktionov, Yu; Gervasi, M; Giusti, P; Grandi, D; Grimm, O; Gu, W Q; Hangarter, K; Hasan, A; Hermel, V; Hofer, H; Huang, M A; Hungerford, W; Ionica, M; Ionica, R; Jongmanns, M; Karlamaa, K; Karpinski, W; Kenney, G; Kenny, J; Kim, W; Klimentov, A; Kossakowski, R; Koutsenko, V F; Kraeber, M; Laborie, G; Laitinen, T; Lamanna, G; Laurenti, G; Lebedev, A; Lee, S C; Levi, G; Levchenko, P M; Liu, C L; Liu, H T; Lopes, I; Lu, G; Lü, Y S; Lübelsmeyer, K; Luckey, D; Lustermann, W; Maña, C; Margotti, A; Mayet, F; McNeil, R R; Meillon, B; Menichelli, M; Mihul, A; Mourao, A; Mujunen, A; Palmonari, F; Papi, A; Park, I H; Pauluzzi, M; Pauss, Felicitas; Perrin, E; Pesci, A; Pevsner, A; Pimenta, M; Plyaskin, V; Pozhidaev, V; Postolache, V; Produit, N; Rancoita, P G; Rapin, D; Raupach, F; Ren, D; Ren, Z; Ribordy, M; Richeux, J P; Riihonen, E; Ritakari, J; Röser, U; Roissin, C; Sagdeev, R; Sartorelli, G; Schwering, G; Scolieri, G; Seo, E S; Shoutko, V; Shoumilov, E; Siedling, R; Son, D; Song, T; Steuer, M; Sun, G S; Suter, H; Tang, X W; Ting, Samuel C C; Ting, S M; Tornikoski, M; Torsti, J; Ulbricht, J; Urpo, S; Usoskin, I; Valtonen, E; Vandenhirtz, J; Velcea, F; Velikhov, E P; Verlaat, B; Vetlitskii, I; Vezzu, F; Vialle, J P; Viertel, Gert M; Vitè, Davide F; Gunten, H V; Wallraff, W; Wang, B C; Wang, J Z; Wang, Y H; Wiik, K; Williams, C; Wu, S X; Xia, P C; Yan, J L; Yan, L G; Yang, C G; Yang, M; Ye, S W; Yeh, P; Xu, Z Z; Zhang, H Y; Zhang, Z P; Zhao, D X; Zhu, G Y; Zhu, W Z; Zhuang, H L; Zichichi, A; Zimmermann, B

    2002-01-01

    The Alpha Magnetic Spectrometer (AMS) is a large acceptance (0.65 sr m sup 2) detector designed to operate in the International Space Station (ISS) for three years. The purposes of the experiment are to search for cosmic antimatter and dark matter and to study the composition and energy spectrum of the primary cosmic rays. A 'scaled-down' version has been flown on the Space Shuttle Discovery for 10 days in June 1998. The complete AMS is programmed for installation on the ISS in October 2003 for an operational period of 3 yr. This contribution reports on the experimental configuration that will be installed on the ISS.

  8. The Alpha Magnetic Spectrometer (AMS)

    International Nuclear Information System (INIS)

    The Alpha Magnetic Spectrometer (AMS) is a large acceptance (0.65 sr m2) detector designed to operate in the International Space Station (ISS) for three years. The purposes of the experiment are to search for cosmic antimatter and dark matter and to study the composition and energy spectrum of the primary cosmic rays. A 'scaled-down' version has been flown on the Space Shuttle Discovery for 10 days in June 1998. The complete AMS is programmed for installation on the ISS in October 2003 for an operational period of 3 yr. This contribution reports on the experimental configuration that will be installed on the ISS

  9. The Alpha Magnetic Spectrometer (AMS)

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, J.; Alpat, B.; Ambrosi, G.; Anderhub, H.; Ao, L.; Arefiev, A.; Azzarello, P.; Babucci, E.; Baldini, L.; Basile, M.; Barancourt, D.; Barao, F.; Barbier, G.; Barreira, G.; Battiston, R.; Becker, R.; Becker, U.; Bellagamba, L.; Bene, P.; Berdugo, J.; Berges, P.; Bertucci, B.; Biland, A.; Bizzaglia, S.; Blasko, S.; Boella, G.; Boschini, M.; Bourquin, M.; Brocco, L.; Bruni, G.; Buenerd, M.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Camps, C.; Cannarsa, P.; Capell, M.; Casadei, D.; Casaus, J.; Castellini, G.; Cecchi, C.; Chang, Y.H.; Chen, H.F.; Chen, H.S.; Chen, Z.G.; Chernoplekov, N.A.; Chiueh, T.H.; Chuang, Y.L.; Cindolo, F.; Commichau, V.; Contin, A. E-mail: contin@bo.infn.it; Crespo, P.; Cristinziani, M.; Cunha, J.P. da; Dai, T.S.; Deus, J.D.; Dinu, N.; Djambazov, L.; DAntone, I.; Dong, Z.R.; Emonet, P.; Engelberg, J.; Eppling, F.J.; Eronen, T.; Esposito, G.; Extermann, P.; Favier, J.; Fiandrini, E.; Fisher, P.H.; Fluegge, G.; Fouque, N.; Galaktionov, Yu.; Gervasi, M.; Giusti, P.; Grandi, D.; Grimm, O.; Gu, W.Q.; Hangarter, K.; Hasan, A.; Hermel, V.; Hofer, H.; Huang, M.A.; Hungerford, W.; Ionica, M.; Ionica, R.; Jongmanns, M.; Karlamaa, K.; Karpinski, W.; Kenney, G.; Kenny, J.; Kim, W.; Klimentov, A.; Kossakowski, R.; Koutsenko, V.; Kraeber, M.; Laborie, G.; Laitinen, T.; Lamanna, G.; Laurenti, G.; Lebedev, A.; Lee, S.C.; Levi, G.; Levtchenko, P.; Liu, C.L.; Liu, H.T.; Lopes, I.; Lu, G.; Lu, Y.S.; Luebelsmeyer, K.; Luckey, D.; Lustermann, W.; Mana, C.; Margotti, A.; Mayet, F.; McNeil, R.R.; Meillon, B.; Menichelli, M.; Mihul, A.; Mourao, A.; Mujunen, A.; Palmonari, F.; Papi, A.; Park, I.H.; Pauluzzi, M.; Pauss, F.; Perrin, E.; Pesci, A.; Pevsner, A.; Pimenta, M.; Plyaskin, V.; Pojidaev, V.; Postolache, V.; Produit, N.; Rancoita, P.G.; Rapin, D.; Raupach, F.; Ren, D.; Ren, Z.; Ribordy, M.; Richeux, J.P.; Riihonen, E.; Ritakari, J.; Roeser, U.; Roissin, C.; Sagdeev, R.; Sartorelli, G.; Schultz von Dratzig, A.; Schwering, G.; Scolieri, G.; Seo, E.S.; Shoutko, V.

    2002-02-01

    The Alpha Magnetic Spectrometer (AMS) is a large acceptance (0.65 sr m{sup 2}) detector designed to operate in the International Space Station (ISS) for three years. The purposes of the experiment are to search for cosmic antimatter and dark matter and to study the composition and energy spectrum of the primary cosmic rays. A 'scaled-down' version has been flown on the Space Shuttle Discovery for 10 days in June 1998. The complete AMS is programmed for installation on the ISS in October 2003 for an operational period of 3 yr. This contribution reports on the experimental configuration that will be installed on the ISS.

  10. Reflectance spectra of subarctic lichens

    International Nuclear Information System (INIS)

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the mid latitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 μm, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future. (author)

  11. On non-forking spectra

    CERN Document Server

    Chernikov, Artem; Shelah, Saharon

    2012-01-01

    Non-forking is one of the most important notions in modern model theory capturing the idea of a generic extension of a type (which is a far-reaching generalization of the concept of a generic point of a variety). To a countable first-order theory we associate its non-forking spectrum - a function of two cardinals kappa and lambda giving the supremum of the possible number of types over a model of size lambda that do not fork over a sub-model of size kappa. This is a natural generalization of the stability function of a theory. We make progress towards classifying the non-forking spectra. On the one hand, we show that the possible values a non-forking spectrum may take are quite limited. On the other hand, we develop a general technique for constructing theories with a prescribed non-forking spectrum, thus giving a number of examples. In particular, we answer negatively a question of Adler whether NIP is equivalent to bounded non-forking. In addition, we answer a question of Keisler regarding the number of cut...

  12. Methodology for analyzing weak spectra

    International Nuclear Information System (INIS)

    There is considerable interest in quantifying radionuclide transfer between environmental compartments. However, in many cases, it can be a challenge to detect concentrations of gamma-emitting radionuclides due to their low levels in environmental samples. As a result, it is valuable to develop analytical protocols to ensure consistent analysis of the areas under weak peaks. The current study has focused on testing how reproducibly peak areas and baselines can be determined using two analytical approaches. The first approach, which can be carried out using Maestro software, involves extracting net counts under a curve without fitting a functional form to the peak, whereas the second approach, which is used by most other peak fitting programs, determines net counts from spectra by fitting a Gaussian form to the data. It was found that the second approach produces more consistent peak area and baseline measurements, with the ability to de-convolute multiple, overlapping peaks. In addition, programs, such as Peak Fit, which can be used to fit a form to spectral data, often provide goodness of fit analyses, since the Gaussian form can be described using a characteristic equation against which peak data can be tested for their statistical significance. (author)

  13. Does the fine structure constant vary? A third quasar absorption sample consistent with varying alpha

    CERN Document Server

    Webb, J K; Flambaum, V V; Curran, S J

    2003-01-01

    We report preliminary results from a third sample of quasar absorption line spectra from the Keck telescope which has been studied to search for any possible variation of the fine structure constant, alpha. This third sample, which is larger than the sum of the two previously published samples, shows the same effect, and also gives, as do the previous two samples, a significant result. The combined sample yields a highly significant effect, da/a = (alpha_z - alpha_0)/alpha_0 = -0.57 +/- 0.10 x 10^{-5}, averaged over the redshift range 0.2 < z < 3.7. We include a brief discussion of small-scale kinematic structure in quasar absorbing clouds. However, kinematics are unlikely to impact significantly on the averaged non-zero da/a above, and we have so far been unable to identify any systematic effect which can explain it. New measurements of quasar spectra obtained using independent instrumentation and telescopes are required to properly check the Keck results.

  14. Can a many-nucleon structure be visible in bremsstrahlung emission during $\\alpha$ decay?

    CERN Document Server

    Maydanyuk, Sergei P; Zou, Li-Ping

    2015-01-01

    We analyze if the nucleon structure of the $\\alpha$ decaying nucleus can be visible in the experimental bremsstrahlung spectra of the emitted photons which accompany such a decay. We develop a new formalism of the bremsstrahlung model taking into account distribution of nucleons in the $\\alpha$ decaying nuclear system. We conclude the following: (1) After inclusion of the nucleon structure into the model the calculated bremsstrahlung spectrum is changed very slowly for a majority of the $\\alpha$ decaying nuclei. However, we have observed that visible changes really exist for the $^{106}{\\rm Te}$ nucleus ($Q_{\\alpha}=4.29$ MeV, $T_{1/2}$=70 mks) even for the energy of the emitted photons up to 1 MeV. This nucleus is a good candidate for future experimental study of this task. (2) Inclusion of the nucleon structure into the model increases the bremsstrahlung probability of the emitted photons. (3) We find the following tendencies for obtaining the nuclei, which have bremsstrahlung spectra more sensitive to the ...

  15. Time-variability of alpha from realistic models of Oklo reactors

    CERN Document Server

    Gould, C R; Lamoreaux, S K

    2006-01-01

    We reanalyze Oklo $^{149}$Sm data using realistic models of the natural nuclear reactors. Disagreements among recent Oklo determinations of the time evolution of $\\alpha$, the electromagnetic fine structure constant, are shown to be due to different reactor models, which led to different neutron spectra used in the calculations. We use known Oklo reactor epithermal spectral indices as criteria for selecting realistic reactor models. Two Oklo reactors, RZ2 and RZ10, were modeled with MCNP. The resulting neutron spectra were used to calculate the change in the $^{149}$Sm effective neutron capture cross section as a function of a possible shift in the energy of the 97.3-meV resonance. We independently deduce ancient $^{149}$Sm effective cross sections, and use these values to set limits on the time-variation of $\\alpha$. Our study resolves a contradictory situation with previous Oklo $\\alpha$-results. Our suggested $2 \\sigma$ bound on a possible time variation of $\\alpha$ over two billion years is stringent: $ -...

  16. Genomic organization of the bovine alpha-S1 casein gene.

    OpenAIRE

    Koczan, D; Hobom, G.; Seyfert, H.M.

    1991-01-01

    We report the sequence of the complete bovine alpha-s1 casein gene eludicating for the first time the genomic organization of an alpha-s type casein gene. Extending over 17508 bp the gene is split into 19 exons, ranging in size from 24 bp to 385 bp. Except for the translational stop codon not a single coding triplet of the alpha-s1 reading frame is disrupted by any of the splice junctions, which all confirm to known splice consensus sequences. Nine out of 16 coding exons begin with a 'GAX' co...

  17. Relativistic Fe K alpha line study in Seyfert 1 galaxies observed with Suzaku

    CERN Document Server

    Mantovani, Giulia; Ponti, Gabriele

    2016-01-01

    We present an analysis of a sample of Seyfert 1 galaxies observed with Suzaku. The aim of this work is to examine critically the evidence for a relativistic Fe K alpha line in the X-ray spectra of these AGN. The sample was compiled from those sources in which a relativistic component was missing in at least one XMM-Newton observation. We analysed the Suzaku spectra of these objects in order to have more constraints on the high energy emission, including the Compton reflection hump. The results show that the relativistic Fe K alpha line is detected (at >95% confidence) in all sources observed with high signal-to-noise ratio (e.g. where the counts in the 5-7 keV energy band are > 4 x 10^4). This is in agreement with the idea that relativistic lines are a ubiquitous feature in the spectra of Seyfert galaxies, but are often difficult to detect without very high quality data. We also investigate the relation between the Fe K alpha line and the reflection continuum at high energies. For most of the sample, the stre...

  18. Measurement of (222)Rn by absorption in plastic scintillators and alpha/beta pulse shape discrimination.

    Science.gov (United States)

    Mitev, Krasimir K

    2016-04-01

    This work demonstrates that common plastic scintillators like BC-400, EJ-200 and SCSF-81 absorb radon and their scintillation pulse decay times are different for alpha- and beta-particles. This allows the application of pulse shape analysis for separation of the pulses of alpha- and beta-particles emitted by the absorbed radon and its progeny. It is shown that after pulse shape discrimination of beta-particles' pulses, the energy resolution of BC-400 and EJ-200 alpha spectra is sufficient to separate the peaks of (222)Rn, (218)Po and (214)Po and allows (222)Rn measurements that are unaffected by the presence of thoron ((220)Rn) in the environment. The alpha energy resolution of SCSF-81 in the experiments degrades due to imperfect collection of the light emitted inside the scintillating fibers. The experiments with plastic scintillation microspheres (PSM) confirm previous findings of other researchers that PSM have alpha-/beta-discrimination properties and show suitability for radon measurements. The diffusion length of radon in BC-400 and EJ-200 is determined. The pilot experiments show that the plastic scintillators are suitable for radon-in-soil-gas measurements. Overall, the results of this work suggest that it is possible to develop a new type of radon measurement instruments which employ absorption in plastic scintillators, pulse-shape discrimination and analysis of the alpha spectra. Such instruments can be very compact and can perform continuous, real-time radon measurements and thoron detection. They can find applications in various fields from radiation protection to earth sciences. PMID:26851823

  19. A study of ice response spectra

    Institute of Scientific and Technical Information of China (English)

    LIU Chunguang; JIA Lingling

    2009-01-01

    Some problems concerning the ice forces and ice response spectra are studied from both theoretical and practical points of view. On the basis of structural analysis,the analysis method of ice response spectra is proposed, since it plays an important role in the prediction of maximum structural response in cold regions. And it is illustrated that it is easy to study the structural response to ice using the ice response spectra.

  20. Circumstellar Molecular Spectra towards Evolved Stars

    CERN Document Server

    Bakker, E J

    1997-01-01

    In this paper we discuss the relevance of, and possible scientific gains which can be acquired from studying circumstellar molecular spectra toward evolved stars. Where can we expect circumstellar molecular spectra, why would we want to study these spectra, which molecules might be present, and what can we learn from these studies? We present an overview of reported detections, and discuss some of the results.

  1. Structure of high-resolution NMR spectra

    CERN Document Server

    Corio, PL

    2012-01-01

    Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

  2. Optical absorption spectra of Ag-11 isomers

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Fernandez, E. M.

    The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground-stale confi......The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground...

  3. Infrared spectra of thyroid tumor tissues

    Science.gov (United States)

    Tolstorozhev, G. B.; Skornyakov, I. V.; Butra, V. A.

    2010-07-01

    We used infrared spectroscopy methods to study thyroid tumor tissues removed during surgery. The IR spectra of the surgical material are compared with data from histological examination. We show that in malignant neoplasms, the spectra of proteins in the region of C=O vibrations are different from the spectra of these substances in benign tumors and in tissues outside the pathological focus at a distance >1 cm from the margin of the tumor. The differences in the spectra are due to changes in the supermolecular structure of the proteins, resulting from rearrangement of the system of hydrogen bonds. We identify the spectral signs of malignant pathologies.

  4. Dynamic Radio Spectra from two Fireballs

    OpenAIRE

    Obenberger, K. S.; Taylor, G. B.; Lin, C. S.; J. Dowell; Schinzel, F. K.; Stovall, K.

    2015-01-01

    We present dynamic spectra from the LWA1 telescope of two large meteors (fireballs) observed to emit between 37 and 54 MHz. These spectra show the first ever recorded broadband measurements of this newly discovered VHF emission. The spectra show that the emission is smooth and steep, getting very bright at lower frequencies. We suggest that this signal is possibly emission of Langmuir waves and that these waves could be excited by a weak electron beam within the trail. The spectra of one fire...

  5. Neutron and photon spectra in LINACs

    International Nuclear Information System (INIS)

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10–6 and 1 MeV. Neutron and the Bremsstrahlung spectra show the same features regardless of the linac voltage. - Highlights: ► With MCNPX code realistic models of two LINACs were built. ► Photon and neutron spectra below the flattening filter and at the isocenter were calculated. ► Neutron spectrum at the flattening filter was compared against the Tosi et al. source-term model. ► Tosi et al. model underestimates the neutron contribution below 1 MeV. ► Photon spectra look alike to those published in literature.

  6. Limits on the time variation of the electromagnetic fine-structure constant in the low energy limit from absorption lines in the spectra of distant quasars

    CERN Document Server

    Srianand, R; Petitjean, P; Aracil, B; Srianand, Raghunathan; Chand, Hum; Petitjean, Patrick; Aracil, Bastien

    2004-01-01

    Most of the successful physical theories rely on the constancy of few fundamental quantities (such as the speed of light, $c$, the fine-structure constant, \\alpha, the proton to electron mass ratio, \\mu, etc), and constraining the possible time variations of these fundamental quantities is an important step toward a complete physical theory. Time variation of \\alpha can be accurately probed using absorption lines seen in the spectra of distant quasars. Here, we present the results of a detailed many-multiplet analysis performed on a new sample of Mg II systems observed in high quality quasar spectra obtained using the Very Large Telescope. The weighted mean value of the variation in \\alpha derived from our analysis over the redshift range 0.4alpha/\\alpha = (-0.06+/-0.06) x 10^{-5}. The median redshift of our sample (z=1.55) corresponds to a look-back time of 9.7 Gyr in the most favored cosmological model today. This gives a 3\\sigma limit, -2.5 x 10^{-16} yr^-1 <(\\Delta\\alpha/\\alpha\\D...

  7. Confidence Intervals for Cronbach's Coefficient Alpha Values

    OpenAIRE

    Koning, Alex; Franses, Philip Hans

    2003-01-01

    textabstractCoefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, which amounts to computing the confidence intervals of an alpha, as these intervals automatically account for differences across the numbers of items. We also give appropriate statistics to test for ...

  8. Confidence Intervals for Cronbach's Coefficient Alpha Values

    OpenAIRE

    Koning, A. J.; Franses, Ph.H.B.F.

    2003-01-01

    Coefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, which amounts to computing the confidence intervals of an alpha, as these intervals automatically account for differences across the numbers of items. We also give appropriate statistics to test for significant ...

  9. Conformons in alpha-helical proteins

    CERN Document Server

    Atanasov, Victor

    2009-01-01

    We propose the conformon as a quantum of conformational change for energy transfer in alpha-helical proteins. The underlying mechanism of interaction between the quantum of excitation and the conformational degrees of freedom is nonlinear and leads to solitary wave packets of conformational energy. The phenomenon is specific to alpha-helices and not to beta-sheets in proteins due to the three strands of hydrogen bonds constituting the alpha-helical backbone.

  10. Particle unstable excited states in 9Be: Influence of beta recoil and width on delayed particle spectra

    International Nuclear Information System (INIS)

    The light nucleus 9Be has been studied through the emission of beta-delayed neutrons and alpha particles from 9Li. The activity was produced at the ISOLDE facility in fragmentation reactions induced either by 600 MeV proton or 910 MeV 3He beams from the CERN Synchro-cyclotron. After mass separation, neutron spectra were recorded using 3He-filled proportional counters, while surface barriere detectors were used for the spectroscopy of alpha particles. Effects on the spectrum shape induced by recoil and polarization phenomena as well as large widths of the intermediate states are discussed. (orig.)

  11. Fluctuation analysis of rotational spectra

    International Nuclear Information System (INIS)

    The compound state rotational degree of freedom is ''damped'' in the sense that the electric quadrupole decay of a single quantum state with angular momentum I exhibits a spectrum of final states all having spin I-2. In actual experiments, the cascade of γ-rays associated with each of the members of the ensemble of compound nuclei uses each of the ''discrete'' transitions many more times than the ''continuum'' transitions. Relatively large and small fluctuations in the recorded coincidence spectrum ensue, respectively. The analysis of the fluctuations will be shown to be instrumental to gain insight into the phenomenon of rotational damping. For this purpose, two- and higher-fold coincidence spectra emitted from rotating nuclei are analyzed with respect to the count fluctuations. The coincidences from consecutive γ-rays emitted from discrete rotational bands generate ridges in the Eγ1.Eγ2 spectrum, and the fluctuation analysis of the ridges is based upon the ansatz of a random selection of transition energies from band to band. This ansatz is supported by a cranked mean-field calculation for the nucleus 168Yb, as well as by analyzing resolved bands in 168Yb and its neighbors. The fluctuation analysis of the central valley (Eγ1=Eγ2) is based upon the ansatz of fluctuations in the intensity of the transitions of Porter-Thomas type superposed on a smooth spectrum of transition energies. This ansatz is again supported by a mixed-band calculation. The mathematical treatment of count fluctuations is formulated in general (orig.)

  12. Quantum time scales in alpha tunneling

    CERN Document Server

    Kelkar, N G; Nowakowski, M

    2008-01-01

    The theoretical treatment of alpha decay by Gamow is revisited by investigating the quantum time scales in tunneling. The time spent by an alpha particle in front of the barrier and traversing it before escape is evaluated using microscopic alpha nucleus potentials. The half-life of a nucleus is shown to correspond to the time spent by the alpha knocking in front of the barrier. Calculations for medium and super heavy nuclei show that from a multitude of available tunneling time definitions, the transmission dwell time gives the bulk of the lifetime of the decaying state, in most cases.

  13. Prospects for alpha particle studies on TFTR

    International Nuclear Information System (INIS)

    TFTR is expected to produce approximately 5 MW of alpha heating during the D/T Q ≅ 1 phase of operation in 1990. At that point the collective confinement properties and the heating effects of alpha particles become accessible for study for the first time. This paper outlines the potential performance of TFTR with respect to alpha particle production, the diagnostics which will be available for alpha particle measurements, and the physics issues which can be studied both before and during D/T operation

  14. [Alpha-linolenic acid and cardiovascular diseases].

    Science.gov (United States)

    Ristić-Medić, Danijela; Ristić, Gordana; Tepsić, Vesna

    2003-01-01

    IMPORTANCE AND METABOLISM OF ALPHA-LINOLENIC ACID: Alpha-linolenic acid is an essential fatty acid which cannot be produced in the body and must be taken by food. Both in animals and humans, alpha-linolenic acid is desaturated and elongated into eicosapentaenoic and docosahexaenoic acid. It is also incorporated into plasma and tissue lipids and its conversion is affected by levels of linoleic acid. POTENTIAL ROLE IN PATHOGENESIS OF CARDIOVASCULAR DISEASES: Diet enriched in n-3 fatty acids, especially alpha-linolenic acid, reduces the incidence of cardiac death. Studies have shown that alpha linolenic acid prevents ventricular fibrillation which is the main cause of cardiac death. Studies in rats suggest that alpha-linolenic acid may be more effective in preventing ventricular fibrillations than eicosapentaenoic and docosahexaenoic acid. Furthermore, alpha-linolenic acid is the main fatty acid decreasing platalet aggregation which is an important step in thrombosis i.e. non-fatal myocardial infarction and stroke. DIETARY SOURCES AND NUTRITION RECOMMENDATIONS: Dietary sources include flaxseed and flaxseed oil, canola oil, soybean and soybean oil, pumpkin seed and pumpkin oil, walnuts and walnut oil. Strong evidence supports beneficial effects of alpha-linolenic acid and its dietary sources should be incorporated into balanced diet for prevention of cardiovascular diseases. The recommended daily intake is 2 g with a ratio of 5/1 for linoleic/alpha-linolenic acid. PMID:15510909

  15. Alpha particle problems in shielded support systems

    International Nuclear Information System (INIS)

    Alpha particle confinement is considered in the case of internal conductor systems with magnetically shielded supports. The treatment includes problems of energy transfer to the background plasma, the balance between radiation losses and alpha particle heating, mirror confinement in the main poloidal field, the cut-off and shielding conditions at the supports, ambipolar electric fields, wall interaction, and support location. With a proper and technically realizable choice of parameter values, it should become possible to achieve alpha particle heating as well as to manage the reactor technological problems due to alpha particle interaction with the supports. (Auth.)

  16. Quantum Estimates of Alpha Emitter Life Time

    Directory of Open Access Journals (Sweden)

    B. Santoso

    2006-01-01

    Full Text Available Quantum estimates of several alpha radioactive life time have been made using the probability of quantum tunneling through the nuclear potential barrier. It is assumed that for a given nucleus with mass number A and isotopic number Z, there exists an alpha particle moving freely back and forth in the nucleus with mass and isotopic numbers A -4 and Z-2. If the probability of penetrating the nuclear potential barrier is Τ, then after N times (N=1/Τ hitting the barrier an alpha particle is emitted. To obtain the elapsed time for emitting an alpha particle requires N times τ0, where τ0 is the time travel for alpha across the nuclear diameter, which is dependent on alpha energy. It is assumed here that this kinetic energy is the same as the emitted energy. The emitting alpha kinetic energies here are calculated by the difference of the masses of the parent and daughter nuclei and the alpha particles. They are in closed agreement with the experimental observations. While the alpha radioactive life time are not the same order of magnitudes but give the same linearity on the logarithmic scale as function of the inverse square root of energy.

  17. $\\alpha_{s}$ from the (revised) ALEPH data for $\\tau$ decay

    CERN Document Server

    Boito, Diogo; Maltman, Kim; Osborne, James; Peris, Santiago

    2014-01-01

    We present a new analysis of $\\alpha_s$ from hadronic $\\tau$ decays based on the recently revised ALEPH data. The analysis is based on a strategy which we previously applied to the OPAL data. We critically compare our strategy to the one traditionally used and comment on the main differences. Our analysis yields the values $\\alpha_s(m_\\tau^2)=0.296\\pm 0.010$ using fixed-order perturbation theory, and $\\alpha_s(m_\\tau^2)=0.310\\pm 0.014$ using contour-improved perturbation theory. Averaging these values with our previously obtained values from the OPAL data, we find $\\alpha_s(m_\\tau^2)=0.303\\pm 0.009$, respectively, $\\alpha_s(m_\\tau^2)=0.319\\pm 0.012$, as the most reliable results for $\\alpha_s$ from $\\tau$ decays currently available.

  18. The Alpha Magnetic Spectrometer on the International Space Station

    CERN Document Server

    Paniccia, M

    2008-01-01

    The Alpha Magnetic Spectrometer (AMS) is a particle physics detector designed to measure charged cosmic rays spectra up to TV region, with high energy photon detection capability up to few hundred GeV. With the large acceptance, the long duration (3 years) and the state of the art particle identification techniques, AMS will provide the most sensitive search for the existence of antimatter nuclei and for the origin of dark matter. The detector is being constructed with an eight layers Silicon Tracker inside a large superconducting magnet, providing a ~ 0.8 Tm2 bending power and an acceptance of ~ 0.5 m2sr. A Transition Radiation Detector and a 3D Electromagnetic Calorimeter allow for electron, positron and photon identification, while independent velocity measurements are performed by a Time of Flight scintillating system and a Ring Image Cherenkov detector. The overall construction is due to be completed by 2008.

  19. Sample variance and Lyman-alpha forest transmission statistics

    CERN Document Server

    Rollinde, Emmanuel; Schaye, Joop; Pâris, Isabelle; Petitjean, Patrick

    2012-01-01

    We compare the observed probability distribution function of the transmission in the \\HI\\ Lyman-alpha forest, measured from the UVES 'Large Programme' sample at redshifts z=[2,2.5,3], to results from the GIMIC cosmological simulations. Our measured values for the mean transmission and its PDF are in good agreement with published results. Errors on statistics measured from high-resolution data are typically estimated using bootstrap or jack-knife resampling techniques after splitting the spectra into chunks. We demonstrate that these methods tend to underestimate the sample variance unless the chunk size is much larger than is commonly the case. We therefore estimate the sample variance from the simulations. We conclude that observed and simulated transmission statistics are in good agreement, in particular, we do not require the temperature-density relation to be 'inverted'.

  20. Correction of diagnostic x-ray spectra measured with CdTe and CdZnTe detectors

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, M. [Osaka Univ., Suita (Japan). Medical School; Kanamori, H.; Toragaito, T.; Taniguchi, A.

    1996-07-01

    We modified the formula of stripping procedure presented by E. Di. Castor et al. We added the Compton scattering and separated K{sub {alpha}} radiation of Cd and Te (23 and 27keV, respectively). Using the new stripping procedure diagnostic x-ray spectra (object 4mm-Al) of tube voltage 50kV to 100kV for CdTe and CdZnTe detectors are corrected with comparison of those spectra for the Ge detector. The corrected spectra for CdTe and CdZnTe detectors coincide with those for Ge detector at lower tube voltage than 70kV. But the corrected spectra at higher tube voltage than 70kV do not coincide with those for Ge detector. The reason is incomplete correction for full energy peak efficiencies of real CdTe and CdZnTe detectors. (J.P.N.)

  1. On the estimation of stellar parameters with uncertainty prediction from Generative Artificial Neural Networks: application to Gaia RVS simulated spectra

    CERN Document Server

    Dafonte, C; Manteiga, M; Garabato, D; Alvarez, M A; Ulla, A; Prieto, C Allende

    2016-01-01

    Aims. We present an innovative artificial neural network (ANN) architecture, called Generative ANN (GANN), that computes the forward model, that is it learns the function that relates the unknown outputs (stellar atmospheric parameters, in this case) to the given inputs (spectra). Such a model can be integrated in a Bayesian framework to estimate the posterior distribution of the outputs. Methods. The architecture of the GANN follows the same scheme as a normal ANN, but with the inputs and outputs inverted. We train the network with the set of atmospheric parameters (Teff, logg, [Fe/H] and [alpha/Fe]), obtaining the stellar spectra for such inputs. The residuals between the spectra in the grid and the estimated spectra are minimized using a validation dataset to keep solutions as general as possible. Results. The performance of both conventional ANNs and GANNs to estimate the stellar parameters as a function of the star brightness is presented and compared for different Galactic populations. GANNs provide sig...

  2. Detection of Ly$\\beta$ auto-correlations and Ly$\\alpha$-Ly$\\beta$ cross-correlations in BOSS Data Release 9

    CERN Document Server

    Iršič, Vid; Bailey, Stephen; Eisenstein, Daniel J; Font-Ribera, Andreu; Goff, Jean-Marc Le; Lundgren, Britt; McDonald, Patrick; O'Connell, Ross; Palanque-Delabrouille, Nathalie; Petitjean, Patrick; Rich, Jim; Rossi, Graziano; Schneider, Donald P; Sheldon, Erin S; Yèche, Christophe

    2013-01-01

    The Lyman-$\\beta$ forest refers to a region in the spectra of distant quasars that lies between the rest-frame Lyman-$\\beta$ and Lyman-$\\gamma$ emissions. The forest in this region is dominated by a combination of absorption due to resonant Ly$\\alpha$ and Ly$\\beta$ scattering. When considering the 1D Ly$\\beta$ forest in addition to the 1D Ly$\\alpha$ forest, the full statistical description of the data requires four 1D power spectra: Ly$\\alpha$ and Ly$\\beta$ auto-power spectra and the Ly$\\alpha$-Ly$\\beta$ real and imaginary cross-power spectra. We describe how these can be measured using an optimal quadratic estimator that naturally disentangles Ly$\\alpha$ and Ly$\\beta$ contributions. Using a sample of approximately 60,000 quasar sight-lines from the BOSS Data Release 9, we make the measurement of the one-dimensional power spectrum of fluctuations due to the Ly$\\beta$ resonant scattering. While we have not corrected our measurements for resolution damping of the power and other systematic effects carefully eno...

  3. $\\alpha$-curvatures and $\\alpha$-flows on low dimensional triangulated manifolds

    OpenAIRE

    Ge, Huabin; Xu, Xu

    2015-01-01

    In this paper, we introduce two discrete curvature flows, which are called $\\alpha$-flows on two and three dimensional triangulated manifolds. For triangulated surface $M$, we introduce a new normalization of combinatorial Ricci flow (first introduced by Bennett Chow and Feng Luo \\cite{CL1}), aiming at evolving $\\alpha$ order discrete Gauss curvature to a constant. When $\\alpha\\chi(M)\\leq0$, we prove that the convergence of the flow is equivalent to the existence of constant $\\alpha$-curvatur...

  4. alpha-nucleus potentials, alpha-decay half-lives, and shell closures for superheavy nuclei

    OpenAIRE

    Mohr, Peter

    2006-01-01

    Systematic alpha-nucleus folding potentials are used to analyze alpha-decay half-lives of superheavy nuclei. Preformation factors of about several per cent are found for all nuclei under study. The systematic behavior of the preformation factors and the volume integrals of the potentials allows to predict alpha-decay energies and half-lives for unknown nuclei. Shell closures can be determined from measured alpha-decay energies using the discontinuity of the volume integral at shell closures. ...

  5. The application of alpha spectrometry to the discovery of new elements by heavy-ion beam bombardement

    International Nuclear Information System (INIS)

    Starting with polonium in 1898, alpha spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, alpha spectra have proven simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the ''natural'' alpha decay series led to the very powerful method of ''genetically'' linking the decay of new elements to the well-established alpha emission of ''daughter'' and ''granddaughter'' nuclei. This technique has been used for all recent discoveries of new elements, including Z = 109. Up to mendelevium (Z = 101), thin samples suitable for alpha spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators, new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in helium gas. Subsequent electrical deposition or a helium jet technique yielded samples that were not only thin enough for alpha spectrometry, but also for alpha and beta-recoil experiments. Many variations of these methods have been developed and will be covered in this paper. For the synthesis of element 106, an aerosol-based recoil transport technique was devised. In this most recent experiments, alpha spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10-6 s, while it was 10-1-100 s for helium jets and 101-103 s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyse them with these latest techniques. Again, alpha spectrometry will play a major role, since the expected signature for the decay of a SHE is a sequence of alpha decays followed by spontaneous fission. (orig.)

  6. Experimental spectra unfolding of fast ion backscattering

    International Nuclear Information System (INIS)

    Problems on processing of experimental spectra of fast light ion backscattering are considered to obtain information about element composition in thin films and surface layers of solids. Application of mathematical processing of the spectra is shown to allow considerably to improve analytical characteristics of the ion backscattering method and to expand the field for its application

  7. Spectra of Velocity components over Complex Terrain

    DEFF Research Database (Denmark)

    Panofsky, H. A.; Larko, D.; Lipschut, R.; Stone, G.; Bradley, E. F.; Bowen, Anthony John; Højstrup, Jørgen

    1982-01-01

    horizontal, and decrease when the flow is uphill, for the longitudinal velocity component only. Since vertical-velocity spectra contain relatively less low wavenumber energy than horizontal-velocity spectra, energetic vertical-velocity fluctuations tend to be in equilibrium with local terrain....

  8. Aircraft Measurements of Atmospheric Kinetic Energy Spectra

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Lilly, D. K.

    1983-01-01

    Wind velocity data obtained from a jet airliner are used to construct kinetic energy spectra over the range of wavelengths from 2.5 to 2500 km. The spectra exhibit an approximate -5/3 slope for wavelengths of less than about 150 km, steepening to about -2.2 at larger scales. These results support...

  9. (abstract) Spectra of Comet Hale-Bopp

    Science.gov (United States)

    Hanner, M. S.; Hayward, T. L.; Lynch, D. K.; Russell, R. W.

    1996-01-01

    The spectra of Hale-Bopp were acquired in mid-1996 at R > 3.5 AU. Strong silicate emission is present in all the spectra. The shape of the feature is very similar to that seen in comet P/Halley. This is the first time that a strong silicate feature has been detected in a comet beyond 2 AU.

  10. Expression of the alpha 1, alpha 2 and alpha 3 isoforms of the GABAA receptor in human alcoholic brain.

    Science.gov (United States)

    Lewohl, J M; Crane, D I; Dodd, P R

    1997-03-14

    The expression of the alpha 1, alpha 2 and alpha 3 isoforms of the GABAA receptor was studied in the superior frontal and motor cortices of 10 control, 10 uncomplicated alcoholic and 7 cirrhotic alcoholic cases matched for age and post-mortem delay. The assay was based on competitive RT/PCR using a single set of primers specific to the alpha class of isoform mRNA species, and was normalized against a synthetic cRNA internal standard. The assay was shown to be quantitative for all three isoform mRNA species. Neither the patient's age nor the post-mortem interval significantly affected the expression of any isoform in either cortical area. The profile of expression was shown to be significantly different between the case groups, particularly because alpha 1 expression was raised in both groups of alcoholics of controls. The two groups of alcoholics could be differentiated on the basis of regional variations in alpha 1 expression. In frontal cortex, alpha 1 mRNA expression was significantly increased when uncomplicated alcoholics were compared with control cases whereas alcoholic-cirrhotic cases were not significantly different from either controls or uncomplicated alcoholic cases. In the motor cortex, alpha 1 expression was elevated only when alcoholic-cirrhotic cases were compared with control cases. There was no significant difference between case groups or areas for any other isoform. PMID:9098573

  11. Alpha backgrounds in the DEAP Dark Matter search experiment

    Science.gov (United States)

    Pollmann, Tina

    One of the pressing concerns in Dark Matter detection experiments is ensuring that the potential signal from exceedingly rare Dark Matter interactions is not obscured by background from interactions with more common particles. This work focuses on the ways in which alpha particles from primordial isotopes in the DEAP detector components can cause background events in the region of interest for Dark Matter search, based on both Monte Carlo simulations and data from the DEAP-1 prototype detector. The DEAP experiment uses liquid argon as a target for Dark Matter interactions and relies on the organic electroluminescent dye tetraphenyl butadiene (TPB) to shift the UV argon scintillation light to the visible range. The light yield and pulse shape of alpha particle induced scintillation of TPB, which is an essential input parameter for the simulations, was experimentally determined. An initial mismatch between simulated and measured background spectra could be explained by a model of geometric background events, which was experimentally confirmed and informed the design of certain parts of the DEAP-3600 detector that is under construction at the moment. Modification of the DEAP-1 detector geometry based on this model led to improved background rates. The remaining background was well described by the simulated spectra, and competitive limits on the contamination of acrylic with primordial isotopes were obtained. Purity requirements for the DEAP-3600 detector components were based on this work. The design and testing of a novel large area TPB deposition source, which will be used to make TPB coatings for the DEAP-3600 detector, is described.

  12. The Kinematics of Multiple-Peaked Ly-alpha Emission in Star-Forming Galaxies at z~2-3

    CERN Document Server

    Kulas, Kristin R; Kollmeier, Juna A; Zheng, Zheng; Steidel, Charles C; Hainline, Kevin N

    2011-01-01

    We present new results on the Ly-alpha emission-line kinematics of 18 z~2-3 star-forming galaxies with multiple-peaked Ly-alpha profiles. With our large spectroscopic database of UV-selected star-forming galaxies at these redshifts, we have determined that ~30% of such objects with detectable Ly-alpha emission display multiple-peaked emission profiles. These profiles provide additional constraints on the escape of Ly-alpha photons due to the rich velocity structure in the emergent line. Despite recent advances in modeling the escape of Ly-alpha from star-forming galaxies at high redshifts, comparisons between models and data are often missing crucial observational information. Using Keck II NIRSPEC spectra of H-alpha (z~2) and [OIII] 5007 (z~3), we have measured accurate systemic redshifts, rest-frame optical nebular velocity dispersions and emission-line fluxes for the objects in the sample. Accurate systemic redshifts allow us to translate the multiple-peaked Ly-alpha profiles into velocity space, revealing...

  13. Resting-State Alpha in Autism Spectrum Disorder and Alpha Associations with Thalamic Volume

    Science.gov (United States)

    Edgar, J. Christopher; Heiken, Kory; Chen, Yu-Han; Herrington, John D.; Chow, Vivian; Liu, Song; Bloy, Luke; Huang, Mingxiong; Pandey, Juhi; Cannon, Katelyn M.; Qasmieh, Saba; Levy, Susan E.; Schultz, Robert T.; Roberts, Timothy P. L.

    2015-01-01

    Alpha circuits (8-12 Hz), necessary for basic and complex brain processes, are abnormal in autism spectrum disorder (ASD). The present study obtained estimates of resting-state (RS) alpha activity in children with ASD and examined associations between alpha activity, age, and clinical symptoms. Given that the thalamus modulates cortical RS alpha…

  14. Alpha-Synuclein Binds to the Inner Membrane of Mitochondria in an alpha-Helical Conformation

    NARCIS (Netherlands)

    Robotta, M.; Gerding, H.R.; Vogel, A.; Hauser, K.; Schildknecht, S.; Karreman, C.; Leist, M.; Subramaniam, V.; Drescher, M.

    2014-01-01

    The human alpha-Synuclein (alphaS) protein is of significant interest because of its association with Parkinson's disease and related neurodegenerative disorders. The intrinsically disordered protein (140 amino acids) is characterized by the absence of a well-defined structure in solution. It displa

  15. General Notes on Processes and Their Spectra

    Directory of Open Access Journals (Sweden)

    Gustav Cepciansky

    2012-01-01

    Full Text Available The frequency spectrum performs one of the main characteristics of a process. The aim of the paper is to show the coherence between the process and its own spectrum and how the behaviour and properties of a process itself can be deduced from its spectrum. Processes are categorized and general principles of their spectra calculation and recognition are given. The main stress is put on power spectra of electric and optic signals, as they also perform a kind of processes. These spectra can be directly measured, observed and examined by means of spectral analyzers and they are very important characteristics which can not be omitted at transmission techniques in telecommunication technologies. Further, the paper also deals with non electric processes, mainly with processes and spectra at mass servicing and how these spectra can be utilised in praxis.

  16. Matching coefficients for alpha_s and m_b to O(alpha_s^2) in the MSSM

    CERN Document Server

    Bauer, A; Salomon, J

    2009-01-01

    We compute the exact two-loop matching coefficients for the strong coupling constant alpha_s and the bottom-quark mass m_b within the Minimal Supersymmetric Standard Model (MSSM), taking into account O(alpha_s^2) contributions from Supersymmetric Quantum Chromodynamics (SQCD). We find that the explicit mass pattern of the supersymmetric particles has a significant impact on the predictions of alpha_s and m_b at high energies. Further on, the three-loop corrections exceed the uncertainty due to the current experimental accuracy. In case of the the running bottom-quark mass, they can reach in the large tan(beta) regime up to 30% from the tree-level value.

  17. Design spectra development considering short time histories

    International Nuclear Information System (INIS)

    Two separate programs, MODQKE and MDOF, were written to provide a capability of obtaining equipment spectra from design spectra. MODQKE generates or modifies acceleration histories to conform with design spectra pertaining to, say, a foundation. MDOF is a simple linear modal superposition program that solves for equipment support histories using the design spectra conforming histories as input. Equipment spectra, then, are obtained from the support histories using MODQKE. MODQKE was written to modify or provide new histories with special attention paid to short seismic records. A technique from the open literature was borrowed to generate an initial history that approximates a given response spectrum. Further refinement is done with smoothing cycles in which several correction signals are added to the history in a way that produces a least squares fit between actual and prescribed spectra. Provision is made for history shaping, a baseline correction, and final scaling. MODQKE performance has been demonstrated with seven examples having zero to ten percent damping ratios, and 2.5 seconds to 20 seconds durations and a variety of target spectra. The examples show the program is inexpensive to use. MDOF is a simple modal superposition program. It has no eigensolver, and the user supplies mode shapes, frequencies, and participation factors as input. Floor spectra can be generated from design spectra by using a history from MODQKE that conforms to the design spectrum as input to MDOF. Floor motions from MDOF can be fed back to MODQKE without modification to obtain the floor spectra. A simple example is given to show how equipment mass effects can be incorporated into the MDOF solution. Any transient solution capability can be used to replace MDOF. For example, a direct transient approach may be desirable if both the equipment and floor structures are to be included in the model with different damping fractions. (orig./HP)

  18. {alpha}{sub s} from {tau} decays revisited

    Energy Technology Data Exchange (ETDEWEB)

    Boito, D.R. [Institut fuer Theoretische Teilchenphysik und Kosmologie, RWTH Aachen University, D-52074 Aachen (Germany); Cata, O. [Ludwig-Maximilians-Universitaet Muenchen, Fakultaet fuer Physik, Arnold Sommerfeld Centre for Theoretical Physics, D-80333 Muenchen (Germany); Golterman, M. [Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132 (United States); Jamin, M. [ICREA and IFAE, Universitat Autonoma de Barcelona, E-08193 Bellaterra, Barcelona (Spain); Maltman, K. [Department of Math and Statistics, York University, Toronto, ON M3J 1P3 (Canada); CSSM, University of Adelaide, Adelaide, SA 5005 (Australia); Osborne, J. [Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132 (United States); Peris, S. [Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132 (United States); Departament de Fisica, Universitat Autonoma de Barcelona, E-08193 Bellaterra, Barcelona (Spain)

    2012-04-15

    Being a determination at low energies, the analysis of hadronic {tau} decay data provides a rather precise determination of the strong coupling {alpha}{sub s} after evolving the result to M{sub Z}. At such a level of precision, even small non-perturbative effects become relevant for the central value and error. While those effects had been taken into account in the framework of the operator product expansion, contributions going beyond it, so-called duality violations, have previously been neglected. The following investigation fills this gap through a finite-energy sum rule analysis of {tau} decay spectra from the OPAL experiment, including duality violations and performing a consistent fit of all appearing QCD parameters. The resulting values for {alpha}{sub s}(M{sub {tau}}) are 0.307(19) in fixed-order perturbation theory and 0.322(26) in contour-improved perturbation theory, which translates to the n{sub f}=5 values 0.1169(25) and 0.1187(32) at M{sub Z}, respectively.

  19. GRACES observations of young [alpha/Fe]-rich stars

    CERN Document Server

    Yong, David; Venn, Kim A; Chene, Andre-Nicolas; Keown, Jared; Malo, Lison; Martioli, Eder; Alves-Brito, Alan; Asplund, Martin; Dotter, Aaron; Martell, Sarah L; Melendez, Jorge; Schlesinger, Katharine J

    2016-01-01

    We measure chemical abundance ratios and radial velocities in four massive (i.e., young) [alpha/Fe]-rich red giant stars using high-resolution high-S/N spectra from ESPaDOnS fed by Gemini-GRACES. Our differential analysis ensures that our chemical abundances are on the same scale as the Alves-Brito et al. (2010) study of bulge, thin and thick disk red giants. We confirm that the program stars have enhanced [alpha/Fe] ratios and are slightly metal poor. Aside from lithium enrichment in one object, the program stars exhibit no chemical abundance anomalies when compared to giant stars of similar metallicity throughout the Galaxy. This includes the elements Li, O, Si, Ca, Ti, Cr, Ni, Cu, Ba, La, and Eu. Therefore, there are no obvious chemical signatures that can help to reveal the origin of these unusual stars. While our new observations show that only one star (not the Li-rich object) exhibits a radial velocity variation, simulations indicate that we cannot exclude the possibility that all four could be binarie...

  20. Lyman-alpha Forests cool Warm Dark Matter

    CERN Document Server

    Baur, Julien; Yèche, Christophe; Magneville, Christophe; Viel, Matteo

    2015-01-01

    The free-streaming of keV-scale particles impacts structure growth on scales that are probed by the Lyman-alpha forest of distant quasars. Using an unprecedentedly large sample of medium-resolution QSO spectra from the ninth data release of SDSS, along with a state-of-the-art set of hydrodynamical simulations to model the Lyman-alpha forest in the non-linear regime, we issue the tightest bounds to date on pure dark matter particles: $m_X \\gtrsim 4.35 \\: \\rm{keV}$ (95% CL) for early decoupled thermal relics such as a hypothetical gravitino, and its corresponding bound for a non-resonantly produced right-handed neutrino $m_s \\gtrsim 31.7 \\: \\rm{keV}$ (95% CL). Thanks to SDSS-III data featuring smaller uncertainties and covering a larger redshift range than SDSS-I data, our bounds improve upon those established by previous works and are further at odds with a purely non-resonantly produced sterile neutrino as dark matter.

  1. Mining the HST Treasury: The ASTRAL Reference Spectra for Evolved M Stars

    Science.gov (United States)

    Carpenter, K. G.; Ayres, T.; Harper, G.; Kober, G.; Wahlgren, G. M.

    2012-01-01

    The "Advanced Spectral Library (ASTRAL) Project: Cool Stars" (PI = T. Ayres) is an HST Cycle 18 Treasury Program designed to collect a definitive set of representative, high-resolution (R greater than 100,000) and high signal/noise (S/N greater than 100) UV spectra of eight F-M evolved cool stars. These extremely high-quality STIS UV echelle spectra are available from the HST archive and through the University of Colorado (http://casa.colorado.edu/ayres/ASTRAL/) portal and will enable investigations of a broad range of problems -- stellar, interstellar. and beyond -- for many years. In this current paper, we concentrate on producing a roadrnap to the very rich spectra of the two evolved M stars in the sample, the M3.4 giant Gamma Crucis (GaCrux) and the M2Iab supergiant Alpha Orionis (Betelgeuse) and illustrate the huge increase in coverage and quality that these spectra provide over that previously available from IUE and earlier HST observations. These roadmaps will facilitate the study of the spectra, outer atmospheres, and winds of not only these stars. but also numerous other cool, low-gravity stars and make a very interesting comparison to the already-available atlases of the K2III giant Arcturus.

  2. Local Varying-Alpha Theories

    CERN Document Server

    Barrow, John D

    2014-01-01

    In a recent paper we demonstrated how the simplest model for varying alpha may be interpreted as the effect of a dielectric material, generalized to be consistent with Lorentz invariance. Unlike normal dielectrics, such a medium cannot change the speed of light, and its dynamics obey a Klein-Gordon equation. This work immediately suggests an extension of the standard theory, even if we require compliance with Lorentz invariance. Instead of a wave equation, the dynamics may satisfy a local algebraic relation involving the permittivity and the properties of the electromagnetic field, in analogy with more conventional dielectric (but still preserving Lorentz invariance). We develop the formalism for such theories and investigate some phenomenological implications. The problem of the divergence of the classical self-energy can be solved, or at least softened, in this framework. Some interesting new cosmological solutions for the very early universe are found, including the possibility of a bounce, inflation and e...

  3. Survey Cross-Calibration with The Cannon: APOGEE-scale Stellar Labels from LAMOST Spectra

    CERN Document Server

    Ho, Anna Y Q; Hogg, David W; Rix, Hans-Walter; Liu, Chao; Yang, Fan; Zhang, Yong; Hou, Yonghui; Wang, Yuefei

    2016-01-01

    To capitalize on a diverse set of large spectroscopic stellar surveys, it is essential to develop techniques for precise and accurate survey cross-calibration. Here, we demonstrate that this can be achieved by a data-driven approach to spectral modeling: we use The Cannon (Ness et al. 2015) to cross-calibrate APOGEE and LAMOST, two large-scale surveys that currently yield inconsistent results due to differing experimental setups and data analysis methodologies. The Cannon constructs a predictive model for LAMOST spectra using a reference set of 9952 stars observed in common between the two surveys, taking five labels as ground truth from APOGEE DR12: Teff, log g, [Fe/H], [\\alpha/M], and K-band extinction A_k. The model is then used to infer Teff, log g, [Fe/H], and [\\alpha/M] for 454,180 giant stars in LAMOST DR2, thus tying low-resolution (R=1800) LAMOST spectra to the APOGEE (R=22,500) label scale. Despite being derived directly from LAMOST spectra, which have lower spectral resolution and very different wa...

  4. Confidence Intervals for Cronbach's Coefficient Alpha Values

    NARCIS (Netherlands)

    A.J. Koning (Alex); Ph.H.B.F. Franses (Philip Hans)

    2003-01-01

    textabstractCoefficient Alpha, which is widely used in empirical research, estimates the reliability of a test consisting of parallel items. In practice it is difficult to compare values of alpha across studies as it depends on the number of items used. In this paper we provide a simple solution, wh

  5. Coefficient Alpha Bootstrap Confidence Interval under Nonnormality

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew

    2012-01-01

    Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

  6. DT results of TFTR's alpha collector

    International Nuclear Information System (INIS)

    An escaping alpha collector probe has been developed for TFTR's DT phase to complement the results of the lost alpha scintillator detectors which have been operating on TFTR since 1988. Measurements of the energy distribution of escaping alphas have been made by measuring the range of alphas implanted into nickel foils located within the alpha collector. Exposed samples have been analyzed for 4 DT plasma discharges at plasma currents of 1.0 and 1.8 MA. The results at 1.0 MA are in good agreement with predictions for first orbit alpha loss at 3.5 MeV. The 1.8 MA results, however, indicate a large anomalous loss of partially thermalized alphas at an energy ∼30% below the birth energy and at a total fluence nearly an order of magnitude above expected first orbit loss. This anomalous loss is not observed with the lost alpha scintillator detectors in DT plasmas but does resemble the anomalous delayed loss seen in DD plasmas. Several potential explanations for this loss process are examined. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations

  7. ALPHA experiment facility and Prof. Jeffrey Hangst.

    CERN Multimedia

    Maximilien Brice

    2010-01-01

    Picture 01-07: General views of the ALPHA experiment Picture 5: Andrea Gutierrez, a PhD student from UBC, transfers liquid helium from a storage dewar into the cryostat containing the superconducting magnetic trap used by the ALPHA experiment.Picture 08-11: Jeffery Hangst, spokesperson for ALPHA Picture 12: The ALPHA silicon detector, which surrounds the trapping resion and is used for imaging antiproton annihilations (Credit University of Liverpool) Picture 13: Untrapped antihydrogen atoms annihilating on the inner surface of the ALPHA trap. These are measured by the ALPHA annihilation detector. The events are concentrated at the electrode radius of about 22.3 mm. The coordinates are defined in the Nature article, Figure 1b. Picture 14: The electrodes (gold) for the ALPHA Penning trap being inserted into the vacuum chamber and cryostat assembly. This is the trap used to combine or "mix" positrons and antiprotons to make antihydrogen. (Credit: Niels Madsen ALPHA/Swansea.) Picture 15: Top, a diagram of the...

  8. Single-field $\\alpha$-attractors

    CERN Document Server

    Linde, Andrei

    2015-01-01

    I describe a simple class of $\\alpha$-attractors, generalizing the single-field GL model of inflation in supergravity. The new class of models is defined for $0<\\alpha \\lesssim 1$, providing a good match to the present cosmological data. I also present a generalized version of these models which can describe not only inflation but also dark energy and supersymmetry breaking.

  9. Sensitivity of alpha-decay to the real alpha-nucleus potential

    International Nuclear Information System (INIS)

    The information which can be obtained from studies of low energy alpha-particle scattering from heavy nuclei and from alpha-decay is discussed. The sensitivity of calculated widths and lifetimes for alpha-decay to the real nuclear potential is examined in detail using a formalism based on the unified theory of nuclear reactions. It is shown that a combined study of alpha-decay and alpha-particle scattering at energies near the Coulomb barrier should give a very precise determination of the barrier height and radius, although there is a more uniquely defined separation distance some way beyond the barrier. (orig.)

  10. A low-energy determination of $\\alpha_s$ at three loops

    CERN Document Server

    Vairo, Antonio

    2015-01-01

    We review one of the most accurate low-energy determinations of $\\alpha_s$. Comparing at short distances the QCD static energy at three loops and resummation of the next-to-next-to leading logarithms with its determination in 2+1-flavor lattice QCD, we obtain $\\alpha_s(1.5~{\\rm GeV})=0.336^{+0.012}_{-0.008}$, which corresponds to $\\alpha_s(M_Z)=0.1166^{+0.0012}_{-0.0008}$. We discuss future perspectives.

  11. Practical alpha detectors for site characterization

    International Nuclear Information System (INIS)

    The authors have and are developing a series of practical alpha detectors for alpha characterization. These include soil surface monitors, pipe and duct monitors, air quality and radon monitors, tool monitors, and sample monitors. Two types of these monitors have been transferred to industry thus far for commercialization. Several of these systems have been fully field tested: for example, the soil surface monitor has been used to characterize 11 sites for 7 customers at 3 DOE facilities. Using a new but simple technology, these alpha detectors can be put to use in many areas where conventional alpha probes are impractical or insufficiently sensitive. Use of these alpha detectors in site characterization at the Uranium in Soil Integrated Demonstration at Fernald, at Los Alamos, and elsewhere will be discussed as well as their commercialization and possible further applications

  12. An Alpha Schottky Junction Power Source

    Science.gov (United States)

    Litz, Marc; Carroll, James; Henriquez, Stan

    2011-10-01

    Isotope batteries present solutions for long-lived low power sources. Compact sensors, and electronic circuit boards can be powered for the lifetime of infrastructure. Alpha sources are practical for safety reasons because of the limited distance before energy absorption in materials, and the high energy (~5MeV) per particle. Damage to materials from the alphas limits the practical use. A Schottky diode geometry is created from an alpha foil on a diamond-like crystal. A power source is proposed that takes advantage of the radiation damage tolerance of diamond, combined with the short range of the alpha radiation. The internal field of the Schottky barrier creates a current through the diode from electron-hole pairs created by alpha bombardment in the gap. Calculations of the expected current, circuit model results, and design parameters for a device are described.

  13. Folding model analysis of alpha radioactivity

    CERN Document Server

    Basu, D N

    2003-01-01

    Radioactive decay of nuclei via emission of $\\alpha$ particles has been studied theoretically in the framework of a superasymmetric fission model using the double folding (DF) procedure for obtaining the $\\alpha$-nucleus interaction potential. The DF nuclear potential has been obtained by folding in the density distribution functions of the $\\alpha$ nucleus and the daughter nucleus with a realistic effective interaction. The M3Y effective interaction has been used for calculating the nuclear interaction potential which has been supplemented by a zero-range pseudo-potential for exchange along with the density dependence. The nuclear microscopic $\\alpha$-nucleus potential thus obtained has been used along with the Coulomb interaction potential to calculate the action integral within the WKB approximation. This subsequently yields microscopic calculations for the half lives of $\\alpha$ decays of nuclei. The density dependence and the exchange effects have not been found to be very significant. These calculations...

  14. Effects of a high-pressure treatment on the wheat alpha-amylase inhibitor and its relationship to elimination of allergenicity

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, S [Food Science Center, Niigata University, Ikarashi, Niigata, 950-2181 (Japan); Takanohashi, K; Nishiumi, T [Graduate School of Science and Technology, Niigata University, Ikarashi, Niigata, 950-2181 (Japan); Hara, T [Department of Applied Biological Chemistry, Faculty of Agriculture, Niigata University, Ikarashi, Niigata, 950-2181 (Japan); Odani, S [Department of Living Science and Technology, Faculty of Education and Human Science, Ikarashi, Niigata, 950-2181 (Japan); Suzuki, A, E-mail: shuyama@agr.niigata-u.ac.j [Department of Health and Nutrition, Faculty of Medical Science for Health, Teikyo Heisei University, Ikebukuro, Tokyo, 170-0013 (Japan)

    2010-03-01

    In this study, the effects of high-pressure treatment on structure and allergeincity of alpha amylase inhibitor (a-AI) were investigated. The pressure-induced structural changes of {alpha}-AI were estimated by fluorescence spectra and by fourth derivative UV-spectroscopy for probed tyrosine residues and by circular dichroism (CD) spectroscopy. The changes in the tertiary structure detected by fluorescence spectra and by fourth derivative UV-spectroscopy under high pressure were indicated at over 300 MPa. Measurements of CD spectroscopy suggested that the effects of a high-pressure treatment on changes in the secondary structure of {alpha}-AI were little. From our results, pressure-induced changes of the {alpha}-AI structure were not apparent. On the other hands, the IgE-specific binding activities of pressurized {alpha}-AI to sera from allergic patients against wheat, which is estimated by observations of dot-blotting, were decreased by high-pressure treatment. It is known that the pressure-induced elimination of allergenicity is related to the tertiary structural changes of allergen molecules. This study are suspected that the epitopes of {alpha}-AI do not contain tyrosine residues, and thus the decrease of IgE-specific binding activities is probably caused by the tertiary structural changes of these parts of {alpha}-AI.

  15. Alpha1 and Alpha2 Integrins Mediate Invasive Activity of Mouse Mammary Carcinoma Cells through Regulation of Stromelysin-1 Expression

    Energy Technology Data Exchange (ETDEWEB)

    Lochter, Andre; Navre, Marc; Werb, Zena; Bissell, Mina J

    1998-06-29

    Tumor cell invasion relies on cell migration and extracellular matrix proteolysis. We investigated the contribution of different integrins to the invasive activity of mouse mammary carcinoma cells. Antibodies against integrin subunits {alpha}6 and {beta}1, but not against {alpha}1 and {alpha}2, inhibited cell locomotion on a reconstituted basement membrane in two-dimensional cell migration assays, whereas antibodies against {beta}1, but not against a6 or {alpha}2, interfered with cell adhesion to basement membrane constituents. Blocking antibodies against {alpha}1 integrins impaired only cell adhesion to type IV collagen. Antibodies against {alpha}1, {alpha}2, {alpha}6, and {beta}1, but not {alpha}5, integrin subunits reduced invasion of a reconstituted basement membrane. Integrins {alpha}1 and {alpha}2, which contributed only marginally to motility and adhesion, regulated proteinase production. Antibodies against {alpha}1 and {alpha}2, but not {alpha}6 and {beta}1, integrin subunits inhibited both transcription and protein expression of the matrix metalloproteinase stromelysin-1. Inhibition of tumor cell invasion by antibodies against {alpha}1 and {alpha}2 was reversed by addition of recombinant stromelysin-1. In contrast, stromelysin-1 could not rescue invasion inhibited by anti-{alpha}6 antibodies. Our data indicate that {alpha}1 and {alpha}2 integrins confer invasive behavior by regulating stromelysin-1 expression, whereas {alpha}6 integrins regulate cell motility. These results provide new insights into the specific functions of integrins during tumor cell invasion.

  16. Catalytic Mechanism of Human Alpha-galactosidase

    Energy Technology Data Exchange (ETDEWEB)

    Guce, A.; Clark, N; Salgado, E; Ivanen, D; Kulinskaya, A; Brumer, H; Garman, S

    2010-01-01

    The enzyme {alpha}-galactosidase ({alpha}-GAL, also known as {alpha}-GAL A; E.C. 3.2.1.22) is responsible for the breakdown of {alpha}-galactosides in the lysosome. Defects in human {alpha}-GAL lead to the development of Fabry disease, a lysosomal storage disorder characterized by the buildup of {alpha}-galactosylated substrates in the tissues. {alpha}-GAL is an active target of clinical research: there are currently two treatment options for Fabry disease, recombinant enzyme replacement therapy (approved in the United States in 2003) and pharmacological chaperone therapy (currently in clinical trials). Previously, we have reported the structure of human {alpha}-GAL, which revealed the overall structure of the enzyme and established the locations of hundreds of mutations that lead to the development of Fabry disease. Here, we describe the catalytic mechanism of the enzyme derived from x-ray crystal structures of each of the four stages of the double displacement reaction mechanism. Use of a difluoro-{alpha}-galactopyranoside allowed trapping of a covalent intermediate. The ensemble of structures reveals distortion of the ligand into a {sup 1}S{sub 3} skew (or twist) boat conformation in the middle of the reaction cycle. The high resolution structures of each step in the catalytic cycle will allow for improved drug design efforts on {alpha}-GAL and other glycoside hydrolase family 27 enzymes by developing ligands that specifically target different states of the catalytic cycle. Additionally, the structures revealed a second ligand-binding site suitable for targeting by novel pharmacological chaperones.

  17. Limits on the time variation of the electromagnetic fine-structure constant in the low energy limit from absorption lines in the spectra of distant quasars.

    Science.gov (United States)

    Srianand, R; Chand, H; Petitjean, P; Aracil, B

    2004-03-26

    We present the results of a detailed many-multiplet analysis performed on a new sample of Mg ii systems observed in high quality quasar spectra obtained using the Very Large Telescope. The weighted mean value of the variation in alpha derived from our analysis over the redshift range 0.4quasar absorption line systems. PMID:15089663

  18. Application of alpha spectrometry to the discovery of new elements by heavy-ion-beam bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Nitschke, J.M.

    1983-05-01

    Starting with polonium in 1898, ..cap alpha..-spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, ..cap alpha..-spectra have proved simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the natural ..cap alpha..-decay series led to the very powerful method of genetically linking the decay of new elements to the well-established ..cap alpha..-emission of daughter and granddaughter nuclei. This technique has been used for all recent discoveries of new elements including Z = 109. Up to mendelevium (Z = 101), thin samples suitable for ..cap alpha..-spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in He gas. Subsequent electrical deposition or a He-jet technique yielded samples that were not only thin enough for ..cap alpha..-spectroscopy, but also for ..cap alpha..- and ..beta..-recoil experiments. Many variations of these methods have been developed and are discussed. For the synthesis of element 106 an aerosol-based recoil transport technique was devised. In the most recent experiments, ..cap alpha..-spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10/sup -6/ s; while it was 10/sup -1/ to 10/sup 0/ s for He-jets and 10/sup 1/ to 10/sup 3/ s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyze them with these latest techniques. Again, ..cap alpha..-spectrometry will play a major role since the expected signature for the decay of a SHE is a sequence of ..cap alpha..-decays followed by spontaneous fission.

  19. Application of alpha spectrometry to the discovery of new elements by heavy-ion beam bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Nitschke, J.M. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.)

    1984-06-15

    Starting with polonium in 1898, alpha spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, alpha spectra have proven simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the ''natural'' alpha decay series led to the very powerful method of ''genetically'' linking the decay of new elements to the well-established alpha emission of ''daughter'' and ''granddaughter'' nuclei. This technique has been used for all recent discoveries of new elements, including Z = 109. Up to mendelevium (Z = 101), thin samples suitable for alpha spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators, new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in helium gas. Subsequent electrical deposition or a helium jet technique yielded samples that were not only thin enough for alpha spectrometry, but also for alpha and beta-recoil experiments. Many variations of these methods have been developed and will be covered in this paper. For the synthesis of element 106, an aerosol-based recoil transport technique was devised. In this most recent experiments, alpha spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10/sup -6/ s, while it was 10/sup -1/-10/sup 0/ s for helium jets and 10/sup 1/-10/sup 3/ s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyse them with these latest techniques. Again, alpha spectrometry will play a major role, since the expected signature for the decay of a SHE is a sequence of alpha decays followed by

  20. Human podocytes adhere to the KRGDS motif of the alpha3alpha4alpha5 collagen IV network.

    Science.gov (United States)

    Borza, Corina M; Borza, Dorin-Bogdan; Pedchenko, Vadim; Saleem, Moin A; Mathieson, Peter W; Sado, Yoshikazu; Hudson, Heather M; Pozzi, Ambra; Saus, Juan; Abrahamson, Dale R; Zent, Roy; Hudson, Billy G

    2008-04-01

    Podocyte adhesion to the glomerular basement membrane is required for proper function of the glomerular filtration barrier. However, the mechanism whereby podocytes adhere to collagen IV networks, a major component of the glomerular basement membrane, is poorly understood. The predominant collagen IV network is composed of triple helical protomers containing the alpha3alpha4alpha5 chains. The protomers connect via the trimeric noncollagenous (NC1) domains to form hexamers at the interface. Because the NC1 domains of this network can potentially support integrin-dependent cell adhesion, it was determined whether individual NC1 monomers or alpha3alpha4alpha5 hexamers support podocyte adhesion. It was found that, although human podocytes did not adhere to NC1 domains proper, they did adhere via integrin alphavbeta3 to a KRGDS motif located adjacent to alpha3NC1 domains. Because the KRGDS motif is a site of phosphorylation, its interactions with integrin alphavbeta3 may play a critical role in cell signaling in physiologic and pathologic states. PMID:18235087

  1. Mass Spectra of Tetraselenafulvalenes, Diselenadithiafulvalenes and Tetrathiafulvalenes

    DEFF Research Database (Denmark)

    Andersen, Jan Rud; Egsgaard, Helge; Larsen, Elfinn;

    1978-01-01

    The mass spectra of 13 heterofulvalenes are reported. The spectra show great similarities within the selenium and within the sulphur series. The main difference between the selenium and the sulphur compounds results from the more facile loss of selenium compared with sulphur, and from the first...... fragmentation of the molecular ion, as the selenium fulvalenes lose an alkyne molecule, whereas the sulphur fulvalenes first lose an (SĊR) radical. An important feature of the spectra of the simple heterofulvalenes is the formation of a rearrangement ion by migration of a heteroatom. The mechanism was...

  2. Rotational structure in molecular infrared spectra

    CERN Document Server

    di Lauro, Carlo

    2013-01-01

    Recent advances in infrared molecular spectroscopy have resulted in sophisticated theoretical and laboratory methods that are difficult to grasp without a solid understanding of the basic principles and underlying theory of vibration-rotation absorption spectroscopy. Rotational Structure in Molecular Infrared Spectra fills the gap between these recent, complex topics and the most elementary methods in the field of rotational structure in the infrared spectra of gaseous molecules. There is an increasing need for people with the skills and knowledge to interpret vibration-rotation spectra in ma

  3. Simulation of x-ray fluorescence spectra

    International Nuclear Information System (INIS)

    A method for simulating x-ray fluorescence (XRF) spectra in hybrid densitometry is presented. This technique allows simulation of XRF spectra for solutions with arbitrary concentrations of special nuclear material and minor actinides excited by an x-ray generator. Spectra for mixed uranium and plutonium solutions with U/Pu ratios ranging from 100 to 1 have been generated. This range of ratios applies to most solutions found in plutonium reprocessing plants. XRF simulation can provide important data for estimating instrument precision, evaluating analysis techniques, and training system operators. Applications of XRF simulation in the development of the Los Alamos Hybrid K-Edge/XRF Densitometer system are described

  4. Improvements in differentiation unfolding of radiation spectra

    International Nuclear Information System (INIS)

    Differentiation unfolding is widely used for measurements of neutron spectra in reactors using proton-recoil proportional counters and for measurements of neutron and gamma-ray spectra using scintillators. Current differentiation unfolding codes use various least-squares fits of polynomials to estimate the derivative of numerical data. Simple examples are used to illustrate the errors in unfolded energy spectra that result from the use of least-squares differentiation. An alternative method of numerical differentiation is presented; this method is shown to be free of the errors that result from least-squares differentiation

  5. Spectra distortion by the interstrip gap in spectroscopic silicon strip detectors

    Science.gov (United States)

    Eremin, V.; Verbitskaya, E.; Eremin, I.; Tuboltsev, Yu; Fadeeva, N.; Egorov, N.; Golubkov, S.; Chen, W.; Li, Z.

    2012-07-01

    The NUSTAR experiments to be carried out as the part of the FAIR program (Facility for Antiproton and Ion Research) now under development in GSI, Germany, require unique spectrometers for heavy ions, for an energy range between a hundred keV up to hundreds of MeV. These spectrometers are constructed on the basis of silicon double sided detectors capable of providing simultaneously the energy spectrum of the particles and the position of hit points. The double sided Si strip detectors for high resolution ion spectroscopy and tracking were developed by the PTI-RIMST consortium. Reduced sized detectors were studied with alpha-particles from a 238Pu source to define the spectral response of their p+ side. The energy resolution was measured and found to be the highest, 9.6 keV, in the p+ strips area. The energy spectrum for the particles hit at the interstrip gap was shown to be much broader and have a maximum at the low energy edges. In this study the alpha-particle spectra were measured on the p+ side of strip detector and their shape was found to depend on the p+ strip structure and potential distribution under the strip and in the interstrip gap, where the surface is passivated by SiO2 layer. Therefore, the 2D potential distribution in the interstrip gap was simulated and interpreted through the effective entrance window for alpha-particles. The calculated spectrum of a detector from alpha-particle source has a shape specific to the experimental detector spectral response, i.e., the peak at low energies. These findings are to be taken into account in the analysis of short range particle spectra and may well contribute to further development of spectroscopic single sided and double sided Si strip detectors to be used in investigations in nuclear physics.

  6. R-Matrix description of particle energy spectra produced by low-energy T+T reactions

    CERN Document Server

    Brune, C R; Sayre, D B; Bacher, A D; Hale, G M; Paris, M W

    2015-01-01

    An R-matrix model for three-body final states is presented and applied to a recent measurement of the neutron energy spectrum from the T+T->2n+alpha reaction. The calculation includes the n-alpha and n-n interactions in the final state, angular momentum conservation, antisymmetrization, and the interference between different channels. A good fit to the measured spectrum is obtained, where clear evidence for the 5He ground state is observed. The model is also used to predict the alpha-particle spectrum from T+T as well as particle spectra from 3He+3He. The R-matrix approach presented here is very general, and can be adapted to a wide variety of problems with three-body final states.

  7. Comparison of the radiochemical separation procedures od plutonium applied for its determination in the environmental samples using alpha spectrometry

    International Nuclear Information System (INIS)

    Alpha spectrometry of the plutonium isotopes can be performed only after the perfect plutonium separation from other components of the matrix. So, till now numerous procedures have been elaborated and tested. The communication presents comparison of the plutonium content determination in soil, bones, eggshells and in the reference materials obtained by alpha spectrometry combined with two different separation procedures. The samples were mineralized in the concentrated HCl or HF prior to plutonium electrodeposition or coprecipitation with NdF3. Some other details were also tested in various variants. Quality of the spectra is discussed in terms of all these pre-treatment methods

  8. A sequential extraction procedure to determine Ra and U isotopes by alpha-particle spectrometry in selective leachates

    International Nuclear Information System (INIS)

    A radiochemical sequential extraction procedure has been developed in our laboratory to determine 226Ra and 234,238U by alpha spectrometry in environmental samples. This method has been validated for both radionuclides by comparing in selected samples the values obtained through its application with the results obtained by applying alternative procedures. Recoveries obtained, counting periods applied and background levels found in the alpha spectra give suitable detection limits to allow the Ra and U determination in operational forms defined in riverbed contaminated sediments. Results obtained in these speciation studies show that 226Ra and 234,238U contamination tend to be associated to precipitated forms of the sediments. (author)

  9. Alpha contaminated liquid effluent monitoring

    International Nuclear Information System (INIS)

    The present report takes into consideration the possibility to carry out an in-line control of activity in liquid streams of fuel cycle nuclear plants, epecially for waste streams. The instrument developed for this purpose, has been characterized by means of static and dinamic measurements with Pu and Am bearing solutions. The results so far obtained show that the minimum detectable Pu amount is about .01mg/l and that it is possible to apply such a technique as alarm system able to detect the overcoming of a present threshold of actinides concentrations. The report also presents an approach to the spectra deconvolution in order to determine the amount of single isotopes

  10. Lucid dreaming and alpha activity: a preliminary report.

    Science.gov (United States)

    Ogilvie, R D; Hunt, H T; Tyson, P D; Lucescu, M L; Jeakins, D B

    1982-12-01

    10 good dream recallers spent 2 nights in the sleep lab during which they were awakened 4 times per night from REM sleep, twice during their highest alpha activity in REM, and twice during low REM alpha. 5 were given alpha feedback training prior to sleep onset. Arousals from high alpha REM sleep yielded significantly higher lucidity ratings. Alpha feedback had no effect upon lucidity or REM alpha levels. Similarities between lucid dreams and meditative phenomena are discussed. PMID:7162915

  11. Osmotic fragility test in heterozygotes for alpha and beta thalassaemia.

    OpenAIRE

    Maccioni, L; Cao, A

    1985-01-01

    This study shows that the combination of heterozygous beta thalassaemia and deletion heterozygous (-alpha/alpha alpha) or homozygous (-alpha/-alpha) alpha+ thalassaemia may result in the production of erythrocytes which have normal mean volume and haemoglobinisation but decreased osmotic fragility. Based on this finding and previous studies, which have shown that beta thalassaemia screening by the osmotic fragility test may miss a significant proportion of beta thalassaemia heterozygotes, we ...

  12. Dynamic Radio Spectra from two Fireballs

    CERN Document Server

    Obenberger, K S; Lin, C S; Dowell, J; Schinzel, F K; Stovall, K

    2015-01-01

    We present dynamic spectra from the LWA1 telescope of two large meteors (fireballs) observed to emit between 37 and 54 MHz. These spectra show the first ever recorded broadband measurements of this newly discovered VHF emission. The spectra show that the emission is smooth and steep, getting very bright at lower frequencies. We suggest that this signal is possibly emission of Langmuir waves and that these waves could be excited by a weak electron beam within the trail. The spectra of one fireball displays broadband temporal frequency sweeps. We suggest that these sweeps are evidence of individual expanding clumps of emitting plasma. While some of these proposed clumps may have formed at the very beginning of the fireball event, others must have formed seconds after the initial event.

  13. Dynamic radio spectra from two fireballs

    Science.gov (United States)

    Obenberger, K. S.; Taylor, G. B.; Lin, C. S.; Dowell, J.; Schinzel, F. K.; Stovall, K.

    2015-11-01

    We present dynamic spectra from the Long Wavelength Array telescope of two large meteors (fireballs) observed to emit between 37 and 54 MHz. These spectra show the first ever recorded broadband measurements of this newly discovered VHF emission. The spectra show that the emission is smooth and steep, getting very bright at lower frequencies. We suggest that this signal is possibly emission of Langmuir waves and that these waves could be excited by a bump-on-tail instability within the trail. The spectra of one fireball display broadband temporal frequency sweeps. We suggest that these sweeps are evidence of individual expanding clumps of emitting plasma. While some of these proposed clumps may have formed at the very beginning of the fireball event, others must have formed seconds after the initial event.

  14. Facile hydrothermal synthesis of alpha manganese sesquioxide ({alpha}-Mn{sub 2}O{sub 3}) nanodumb-bells: Structural, magnetic, optical and photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Gnanam, S., E-mail: gnanam.nanoscience@gmail.com [Department of Physics, Presidency College, Chennai 600005, Tamilnadu (India); Rajendran, V. [Department of Physics, Presidency College, Chennai 600005, Tamilnadu (India)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer {alpha}-Mn{sub 2}O{sub 3} nanoparticles sizes of 35-42 nm have been prepared by hydrothermal process. Black-Right-Pointing-Pointer Shapes of {alpha}-Mn{sub 2}O{sub 3}: Dumb-bell, Cauliflower, spherical with rod, spherical with wires. Black-Right-Pointing-Pointer The strong UV emission can be attributed to high purity and perfect crystallinity. Black-Right-Pointing-Pointer Photocatalytic activity of {alpha}-Mn{sub 2}O{sub 3} was studied by degradation of Remazol red B dye. - Abstract: Nanometer scale cubic bixbyite {alpha}-Mn{sub 2}O{sub 3} has been synthesized by a facile hydrothermal method, at a temperature of 450 Degree-Sign C in the presence of various surfactants. The X-ray diffraction (XRD) analysis shows that the average crystallite size of the sample is {approx}35-42 nm. The shapes of the {alpha}-Mn{sub 2}O{sub 3} nanoparticles include: Dumb-bell-like (anionic surfactant), Cauliflower-like (nonionic surfactant), spherical with rods (cationic surfactant) and spherical with wires (surface modifier). The shapes of {alpha}-Mn{sub 2}O{sub 3} nanoparticles depend on the type of surfactant used in the synthesis. The magnetic property of the anionic surfactant assisted sample was primarily studied, using the vibrating sample magnetometer (VSM). The optical absorption spectra confirmed the effectiveness of the selected capping agents, as the anionic capped {alpha}-Mn{sub 2}O{sub 3} colloids absorbed at shorter wavelength than the other agents, indicating a much smaller crystallite size. The property of strong UV emissions may be attributed to the high purity and perfect crystallinity of the as-prepared {alpha}-Mn{sub 2}O{sub 3}. The surfactants-assisted catalyst was tested for its photocatalytic activity towards the photodegradation of the harmful organic dye Remazol Red B, using a multilamp photo reactor. Possible formation mechanisms have also been proposed for the as-synthesized anionic surfactant assisted samples.

  15. Lyman alpha radiation in external galaxies

    Science.gov (United States)

    Neufeld, David A.; Mckee, Christopher F.

    1990-01-01

    The Ly alpha line of atomic hydrogen is often a luminous component of the radiation emitted by distant galaxies. Except for those galaxies which have a substantial central source of non-stellar ionizing radiation, most of the Ly alpha radiation emitted by galaxies is generated within regions of the interstellar medium which are photoionized by starlight. Conversely, much of the energy radiated by photoionized regions is carried by the Ly alpha line. Only hot, massive stars are capable of ionizing hydrogen in the interstellar medium which surrounds them, and because such stars are necessarily short-lived, Ly alpha emission traces regions of active star formation. Researchers argue that the strength of the Ly alpha emission observed from external galaxies may be used to estimate quantitatively the dust content of the emitting region, while the Ly alpha line profile is sensitive to the presence of shock waves. Interstellar dust particles and shock waves are intimately associated with the process of star formation in two senses. First, both dust particles and shock waves owe their existence to stellar activity; second, they may both serve as agents which facilitate the formation of stars, shocks by triggering gravitational instabilities in the interstellar gas that they compress, and dust by shielding star-forming molecular clouds from the ionizing and dissociative effects of external UV radiation. By using Ly alpha observations as a probe of the dust content in diffuse gas at high redshift, we might hope to learn about the earliest epochs of star formation.

  16. Model-based fit procedure for power-law-like spectra

    CERN Document Server

    Milotti, E

    2005-01-01

    $1/f^\\alpha$ noises are ubiquitous and affect many measurements. These noises are both a nuisance and a peculiarity of several physical systems; in dielectrics, glasses and networked liquids it is very common to study this noise to gather useful information. Sometimes it happens that the noise has a power-law shape only in a certain frequency range, and contains other important features, that are however difficult to study because simple fits often fail. Here I propose a model-based fit procedure that performs well on spectra obtained in a molecular dynamics simulation.

  17. HST-COS Observations of AGN. II. Extended Survey of Ultraviolet Composite Spectra from 159 Active Galactic Nuclei

    CERN Document Server

    Stevans, Matthew L; Danforth, Charles W; Tilton, Evan M

    2014-01-01

    The ionizing fluxes from quasars and other active galactic nuclei (AGN) are critical for interpreting their emission-line spectra and for photoionizing and heating the intergalactic medium (IGM). Using far-ultraviolet spectra from the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), we directly measure the rest-frame ionizing continua and emission lines for 159 AGN at redshifts 0.001 10^17.2 cm^-2) and 214 partial Lyman-limit systems (15.0 < log N_HI < 17.2). The 159 AGN exhibit a wide range of FUV/EUV spectral shapes, F_nu \\propto nu^(alpha_nu), typically with -2 < alpha_nu < 0 and no discernible continuum edges at 912A (H I) or 504A (He I). The composite rest-frame continuum shows a gradual break at 1000 A, with mean spectral index alpha_nu = -0.83 +/- 0.09 in the FUV (1200-2000A) steepening to alpha_nu = -1.41 +/- 0.15 in the EUV (500-1000A). We discuss the implications of the UV flux turnovers and lack of continuum edges for the structure of accretion disks, AGN mass inf...

  18. Selection and Characterization of Interesting Grism Spectra

    CERN Document Server

    Meurer, G R

    2006-01-01

    Observations with the ACS Wide Field Camera and G800L grism can produce thousands of spectra within a single WFC field producing a potentially rich treasure trove of information. However, the data are complicated to deal with. Here we describe algorithms to find and characterize spectra of emission line galaxies and supernovae using tools we have developed in conjunction with off the shelf software.

  19. Supernova Neutrino Spectra and Applications to Flavor

    OpenAIRE

    Keil, Mathias Thorsten

    2007-01-01

    We study the flavor-dependent neutrino spectra formation in the core of a supernova (SN) by means of Monte Carlo simulations. Several neutrino detectors around the world are able to detect a high-statistics signal from a galactic SN. From such a signal one may extract information that severely constrains the parameter space for neutrino oscillations. Therefore, reliable predictions for flavor-dependent fluxes and spectra are urgently needed. In all hydrodynamic simulations the treatment of nu...

  20. Origin of zero degeneracy in networks spectra

    CERN Document Server

    Yadav, Alok

    2014-01-01

    Spectra of real world networks exhibit properties which are different from the random networks. One such property is the existence of a very high degeneracy at zero eigenvalues. In this work, we provide all the possible reasons behind occurrence of the zero degeneracy in the networks spectra. Comparison of zero degeneracy in protein-protein interaction networks of six different species and in their corresponding model networks sheds light in understanding the evolution of complex biological systems.

  1. Parameterizing Stellar Spectra Using Deep Neural Networks

    OpenAIRE

    Li, Xiangru; Pan, Ruyang

    2016-01-01

    This work investigates the spectrum parameterization problem using deep neural networks (DNNs). The proposed scheme consists of the following procedures: first, the configuration of a DNN is initialized using a series of autoencoder neural networks; second, the DNN is fine-tuned using a gradient descent scheme; third, stellar parameters ($T_{eff}$, log$~g$, and [Fe/H]) are estimated using the obtained DNN. This scheme was evaluated on both real spectra from SDSS/SEGUE and synthetic spectra ca...

  2. Statistical study of galactic SNR source spectra

    International Nuclear Information System (INIS)

    Broadband modeling of 24 Galactic supernova remnants was performed using a model to test the SNRs for hadronically generated γ-rays by examining combined spectra of π0-decay, bremsstrahlung, inverse compton, and synchrotron radiation. This is the first statistical study of the resulting source spectra, which are reviewed respectively to ascertain the origin of the gamma radiation. This allows a combined review to test the current prepositions of particle acceleration.

  3. Disk-averaged synthetic spectra of Mars

    OpenAIRE

    Tinetti, Giovanna; Meadows, Victoria S.; Crisp, David; Fong, William; Velusamy, Thangasamy; Snively, Heather

    2004-01-01

    The principal goal of the NASA Terrestrial Planet Finder (TPF) and ESA Darwin mission concepts is to directly detect and characterize extrasolar terrestrial (Earth-sized) planets. This first generation of instruments is expected to provide disk-averaged spectra with modest spectral resolution and signal-to-noise. Here we use a spatially and spectrally resolved model of the planet Mars to study the detectability of a planet's surface and atmospheric properties from disk-averaged spectra as a f...

  4. Remote Optical Detection of Alpha Radiation

    International Nuclear Information System (INIS)

    Alpha emitting radiation sources are typically hard to detect with conventional detectors due to the short range of alpha particles in the air. However, previous studies have shown that remote detection of alpha radiation is possible by measuring the ionization-induced fluorescence of air molecules. The alpha-induced ultraviolet (UV) light is mainly emitted by molecular nitrogen and its fluorescence properties are well known. The benefit of this method is the long range of UV photons in the air. Secondly, the detection is possible also under a strong beta and gamma radiation backgrounds as they do not cause localized molecular excitation. In this work, the optical detection was studied using two different detection schemes; spectral separation of fluorescence from the background lighting and coincidence detection of UV photons originating from a single radiative decay event. Our spectrally integrated measurements have shown that one alpha decay event yields up to 400 fluorescence photons in the air and all these UV photons are induced in a 5 ns time-window. On the other hand, the probability of a background coincidence event in 5 ns scale is very rare compared to the number of background photons. This information can be applied in fluorescence coincidence filtering to discriminate the alpha radiation initiated fluorescence signal from much more intense background lighting. A device called HAUVA (Handheld Alpha UV Application) was built during this work for demonstration purposes. HAUVA utilizes spectral filtering and it is designed to detect alpha emitters from a distance of about 40 cm. Using specially selected room lighting, the device is able to separate 1 kBq alpha emitter from the background lighting with 1 second integration time. (author)

  5. Naturally-occurring alpha activity

    International Nuclear Information System (INIS)

    In view of the difficulties of assessing the significance of man-made radioactivity it is important to study for comparison the background of natural radioactivity against which the human race has evolved and lives. It is also important to define the present levels of activity so that it will be possible to detect and study as quickly as possible any changes which may occur owing to the release into the environment of new radioactive materials. Moreover, by the study of the behaviour of natural radioactivity light may be shed upon that of the artificially produced isotopes and a number of analogies traced between the two groups. These concepts have led to studies of naturally-occurring radioactive materials alongside a programme of research into fission products in food, water and air, as well as studies of the metabolism of both sets of materials in the human body. Since the last report there has been a useful increase in our knowledge of natural radioactivity in the biosphere, and its levels relative to the new man-made activities. These studies have necessitated technical developments, particularly in the methods of measuring and identifying alpha-ray emitters, to which group many of the more important natural radioactive materials belong

  6. Diabetes and alpha lipoic acid

    Directory of Open Access Journals (Sweden)

    IssyLaher

    2011-11-01

    Full Text Available Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E and glutathione. It also boosts antioxidant defense system through Nrf2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that a lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy.

  7. Diagnostics for PLX-alpha

    Science.gov (United States)

    Gilmore, Mark; Hsu, Scott

    2015-11-01

    The goal of the Plasma Liner eXperiment PLX-alpha at Los Alamos National Laboratory is to establish the viability of creating a spherically imploding plasma liner for MIF and HED applications, using a spherical array of supersonic plasma jets launched by innovative contoured-gap coaxial plasma guns. PLX- α experiments will focus in particular on establishing the ram pressure and uniformity scalings of partial and fully spherical plasma liners. In order to characterize these parameters experimentally, a suite of diagnostics is planned, including multi-camera fast imaging, a 16-channel visible interferometer (upgraded from 8 channels) with reconfigurable, fiber-coupled front end, and visible and VUV high-resolution and survey spectroscopy. Tomographic reconstruction and data fusion techniques will be used in conjunction with interferometry, imaging, and synthetic diagnostics from modeling to characterize liner uniformity in 3D. Diagnostic and data analysis design, implementation, and status will be presented. Supported by the Advanced Research Projects Agency - Energy - U.S. Department of Energy.

  8. Growth behaviors in the range $e^{r^\\alpha}$

    OpenAIRE

    Brieussel, Jérémie

    2011-01-01

    For every $\\alpha \\leq \\beta$ in a left neighborhood $[\\alpha_0,1]$ of 1, a group $G(\\alpha,\\beta)$ is constructed, the growth function of which satisfies $\\limsup \\frac{\\log \\log b_{G(\\alpha,\\beta)}(r)}{\\log r}=\\alpha$ and $\\liminf \\frac{\\log \\log b_{G(\\alpha,\\beta)}(r)}{\\log r}=\\beta$. When $\\alpha=\\beta$, this provides an explicit uncountable collection of groups with growth functions strictly comparable. On the other hand, oscillation in the case $\\alpha < \\beta$ explains the existence of...

  9. Generation of synthetic gamma spectra with MATLAB

    International Nuclear Information System (INIS)

    Objectives: The aim of this work is the simulation of gamma spectra using the MATLAB program to generate the calibration curves in efficiency, which will be used to measure radioactive waste in drums. They are necessary for the proper characterization of these drums. A Monte Carlo simulation was basically developed with the random number generator Mersenne Twister and nuclear data obtained from NIST. This paper shows the results obtained and difficulties encountered until today. The physical correction of the simulated spectra has been the only aspect we have been working, up to this moment. Procedures: A simplified representation of the 'Laboratorio de Verificacion y Control de la Calidad' was chosen. Drums with cemented liquid waste are routinely measured in this laboratory. The commercial program MCNP was also used to get a valid reference in the field of simulation of spectra. We analyzed the spectra obtained by MATLAB in the light of classical literature photon detection and the spectrum obtained by MCNP. Conclusions: Currently the program developed seems adequate to simulate a measurement in the 'Laboratorio de Verificacion y Control de la Calidad'. The spectra obtained by MATLAB seem to physically represent what is observed in real spectra. However, it is a slow program. The current development efforts are directed to improve the speed of simulation. An alternative is to use the CUDA language for NVIDIA video cards to parallelized the simulation. An adequate simulation of the electronic measuring chain is also needed to obtain better representations of the shapes of the peaks. (author)

  10. Simulation of Gamma Spectra for Spent Fuel

    International Nuclear Information System (INIS)

    'GammaGen' is a Windows software, developed at The Nuclear Research Centre Negev (NRCN) to generate synthetic gamma ray spectra obtained with various detectors. The information on a chosen radio-nuclide is generated according to its activity, its photo peak energy and yield (taken from a data library). The detector efficiency and resolution, and peak to Compton dependence are used to generate a pulse height spectrum for a specific detector. The spectra can be displayed in several modes: as energy lines of the photo peaks, or as Gaussian of each photo peak. The Compton continuum can be included as well. A spectra mixture for different sources can be produced for visual analysis. Spectra can be exported to some other formats, to enable input to other commercial spectra analyzing programs. The main purpose of the program is to generate synthetic distributions for predicting complicated pulse height spectra. In the field of radioactive waste follow-up it can be used to evaluate the efficiency of different shields and the time dependant monitor response at the waste site

  11. $\\alpha_s$ from the updated ALEPH data for hadronic $\\tau$ decays

    CERN Document Server

    Boito, Diogo; Maltman, Kim; Osborne, James; Peris, Santiago

    2015-01-01

    We extract the strong coupling $\\alpha_s(m_\\tau^2)$ from the recently updated ALEPH non-strange spectral functions obtained from hadronic $\\tau$ decays. We apply a self-consistent analysis method, first tested in the analysis of OPAL data, to extract $\\alpha_s(m_\\tau^2)$ and non-perturbative contributions. The analysis yields $\\alpha_s^{\\rm FO}(m_\\tau^2)=0.296\\pm0.010 $, using Fixed Order Perturbation Theory (FOPT), and $\\alpha^{\\rm CI}_s(m_\\tau^2)= 0.310\\pm0.014$, using Contour Improved Perturbation Theory (CIPT). The weighted average of these results with those previously obtained from OPAL data give $\\alpha_s^{\\rm FO}(m_\\tau^2)=0.303\\pm 0.009$ and $\\alpha_s^{\\rm CI}(m_\\tau^2)=0.319\\pm 0.012$, which gives, after evolution to the $Z$ boson mass scale, $\\alpha^{\\rm FO}_s(m_Z^2)=0.1165\\pm0.0012 $ and $\\alpha_s^{\\rm CI}(m_Z^2)=0.1185\\pm0.0015 $, respectively. We observe that non-perturbative effects limit the accuracy with which $\\alpha_s$ can be extracted from $\\tau$ decay data.

  12. First Attempts at Antihydrogen Trapping in ALPHA

    CERN Document Server

    Andresen, G B; Bowe, P D; Bray, C C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Funakoshi, R; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; Van der Werf, D P; Wasilenko, L; Wurtele, J S; Yamazaki, Y; Fujiwara, M C

    2008-01-01

    We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of CPT, possibly probing physics at the Planck Scale. We discuss some of the particle detection techniques used in ALPHA. Preliminary results from commissioning studies of a partial system of the ALPHA Si vertex detector are presented, the results of which highlight the power of annihilation vertex detection capability in antihydrogen studies.

  13. Lyman alpha airglow observations from SORCE SOLSTICE

    Science.gov (United States)

    Dolinar, E.; Snow, M.; Holsclaw, G.; Thomas, G. E.; Woods, T. N.

    2010-12-01

    The Solar Stellar Irradiance Comparison Experiment (SOLSTICE) instrument on board the Solar Radiation Climate Experiment (SORCE) spacecraft in low Earth orbit observes stars every orbit for in-flight calibration. It also observes several star-free regions of the sky near the wavelength of Lyman alpha to correct for airglow emission in the stellar measurements. Although the airglow measurements are only taken during the eclipse portion of the orbit, the look directions cover nearly the entire anti-sunward hemisphere. This seven-year record of Lyman alpha airglow observations (2003-2010) shows the response of the Hydrogen geocorona to changes in the solar Lyman alpha irradiance over the solar cycle.

  14. Alpha particle confinement in tandem mirrors

    International Nuclear Information System (INIS)

    Mechanisms leading to loss of alpha particles from non-axisymmetric tandem mirrors are considered. Stochastic diffusion due to bounce-drift resonances, which can cause rapid radial losses of high-energy alpha particles, can be suppressed by imposing a 20% rise in axisymmetric fields before the quadrupole transition sections. Alpha particles should then be well-confined until thermal energies when they enter the resonant plateau require. A fast code for computation of drift behavior in reactors is described. Sample calculations are presented for resonant particles in a proposed coil set for the Tandem Mirror Next Step

  15. Enzymatic synthesis of l-menthyl alpha-maltoside and l-menthyl alpha-maltooligosides from l-menthyl alpha-glucoside by cyclodextrin glucanotransferase.

    Science.gov (United States)

    Do, Hiroyuki; Sato, Toshiyuki; Kirimura, Kohtaro; Kino, Kuniki; Usami, Shoji

    2002-01-01

    l-Menthyl alpha-D-glucopyranosyl-(1-->4)-alpha-d-glucopyranoside (alpha-MenG2), a novel glycoside of l-menthol, was synthesized enzymatically and its physicochemical properties were characterized. Production of alpha-MenG2 from l-menthyl alpha-d-glucopyranoside (alpha-MenG) was attempted since we had already succeeded in the high-yield production of alpha-MenG using a Xanthomonas campestris enzyme (Nakagawa H., et al. J. Biosci. Bioeng., 89, 138-144, 2000). Through production tests on enzymes, it was confirmed that cyclodextrin glucanotransferase (CGTase) from Bacillus macerans produced l-menthyl alpha-D-maltooligosides (alpha-MenG(n)), containing alpha-MenG2, from alpha-MenG and soluble starch. When 10 ml of a 10 mM citrate-10 mM phosphate buffer (pH 6.0) containing 150 mg of alpha-MenG, 3 g of soluble starch and CGTase was shaken at 70 degrees C for 24 h, a total of 81.8% alpha-MenG was reacted. The molar conversion yields of alpha-MenG2 and alpha-MenG(n) with alpha-glucose degrees of polymerization of 3-18, based on the amount of alpha-MenG supplied, reached 16.1% and 65.7%, respectively. For efficient production of alpha-MenG2, the reaction mixture was treated with alpha-amylase of Aspergillus oryzae, and alpha-MenG(n) were mainly converted into alpha-MenG2: finally, the molar conversion yield of alpha-MenG2 reached 74.2% based on the amount of alpha-MenG supplied. alpha-MenG2 was purified and its molecular structure was confirmed by 13C-NMR, 1H-NMR and two-dimensional HMBC (heteronuclear multiple-bond coherence). alpha-MenG2 and its aqueous solution tasted bitter and a little sweet at first, but in a few minutes, a refreshing flavor and sweetness spread. At 20 degrees C the solubility of alpha-MenG2 in pure water was 29.6 g/100 ml, approximately 1570-fold that of alpha-MenG. PMID:16233280

  16. Simulation of energy spectra of slow He{sup +} ions scattered from a copper surface

    Energy Technology Data Exchange (ETDEWEB)

    Khalal-Kouache, K., E-mail: kkouache@yahoo.fr [Universite des Sciences et de la Technologie Houari Boumediene (USTHB), Faculte de Physique, Laboratoire SNIRM, Bab-Ezzouar, 16111 Algiers (Algeria); Primetzhofer, D.; Bauer, P. [Institut fuer Experimentalphysik, Johannes Kepler Universitaet, Altenbergstr. 69, A-4040 Linz (Austria)

    2011-06-15

    Scattering of low energy (2 keV) He{sup +} ions from a polycrystalline copper surface is studied. Experimental Time-Of-Flight (TOF) spectra are presented for different values of the angle of incidence {alpha} and a fixed scattering angle {theta} = 129{sup o}. Using Monte Carlo simulation, based on the TRIM (TRansport of Ions in Matter) code, energy spectra are calculated and compared to experimental data. The influence of different combinations of interaction potential and inelastic energy loss on the spectrum shape and on the angular distribution of the scattering yield is considered in the simulation. Simulations show very good agreement with the experiment for all investigated geometries. An analysis of the experimental yield of scattered particles in different parts of the spectrum is performed to gain information on the relative contributions of surface single scattering and multiple scattering.

  17. Correlations between density distributions, optical spectra, and ion species in a hydrogen plasma (invited)

    Science.gov (United States)

    Cortázar, O. D.; Megía-Macías, A.; Tarvainen, O.; Kalvas, T.; Koivisto, H.

    2016-02-01

    An experimental study of plasma distributions in a 2.45 GHz hydrogen discharge operated at 100 Hz repetition rate is presented. Ultrafast photography, time integrated visible light emission spectra, time resolved Balmer-alpha emission, time resolved Fulcher Band emission, ion species mass spectra, and time resolved ion species fraction measurements have been implemented as diagnostic tools in a broad range of plasma conditions. Results of plasma distributions and optical emissions correlated with H+, H2 + , and H3 + ion currents by using a Wien filter system with optical observation capability are reported. The magnetic field distribution and strength is found as the most critical factor for transitions between different plasma patterns and ion populations.

  18. ORIGEN-S (α,n) neutron source spectra in borosilicate glass containing HLW

    International Nuclear Information System (INIS)

    There is growing interest in the methodology and computational software for evaluating the (α,n) source spectra produced in mixtures of high-level waste (HLW) and borosilicate glass. The need for this development has been seen in previous work involving the analysis of HLW in borosilicate glass. Descriptions and applications of the ORIGEN-S method of computing neutron source spectra by both (α,n) reactions and spontaneous fission of UO2 spent fuel have been reported previously. This summary presents a significant expansion of the ORIGEN-S (α,n) model to include alpha interactions with the light elements of borosilicate glass. The Battelle/Office of Nuclear Waste Isolation requested this model extension. There is an associated interest in the use of Oak Ridge National Lab. shielding codes for analyzing HLW systems

  19. Determination of alpha_s and W boson leptonic branching ratio from the W and Z cross sections

    CERN Document Server

    Xiao, Weichen

    2016-01-01

    We try to determine the strong coupling alpha_s and the W boson leptonic branching ratio from the W and Z boson production cross section through pp collisions in the LHC. We run the MCFM program together with LHAPDF or HERAPDF les to extract the theoretical prediction of cross sections at different alpha_s in different experiments. We compare the predicted values and the experimental results to do a precise measurement of alpha_s and the branching ratio.

  20. Recent developments in the electronic spectroscopy of amides and alpha-helical polypeptides.

    Science.gov (United States)

    Woody, Robert W; Koslowski, Axel

    2002-12-10

    Recent experimental and theoretical advances in understanding the electronic excited states of simple amides are reviewed. Polarized reflection spectroscopy of single crystals of N-acetylglycine shows that the direction of the first pipi* (NV(1)) transition dipole moment of a secondary amide differs by approximately 15 degrees from that of a primary amide. Ab initio calculations on simple amides support this conclusion. Ab initio studies of di- and tri-amides demonstrate that several inter-amide charge-transfer (CT) transitions occur in the 150-175-nm region, between the NV(1) and NV(2) transitions. When the correct dipole transition moment direction for peptides is used in calculations of the circular dichroism of the alpha-helix, the results are much improved over those from earlier calculations that used the direction for primary amides. Studies that consider the mixing of the NV(1) transition with CT transitions are reviewed. These indicate that such mixing is likely to have a significant effect on the absorption and CD spectra of the alpha-helix and other types of peptide conformation. Nevertheless, the independent systems model gives a reasonable first approximation to the absorption and CD spectra of the alpha-helix. PMID:12488025

  1. On the H$\\alpha$ emission from the $\\beta$ Cephei system

    CERN Document Server

    Schnerr, R S; Oudmaijer, R D; Telting, J H

    2006-01-01

    Be stars, which are characterised by intermittent emission in their hydrogen lines, are known to be fast rotators. This fast rotation is a requirement for the formation of a Keplerian disk, which in turn gives rise to the emission. However, the pulsating, magnetic B1IV star $\\beta$ Cephei is a very slow rotator that still shows H$\\alpha$ emission episodes like in other Be stars, contradicting current theories. We investigate the hypothesis that the H$\\alpha$ emission stems from the spectroscopically unresolved companion of $\\beta$ Cep. Spectra of the two unresolved components have been separated in the 6350-6850\\AA range with spectro-astrometric techniques, using 11 longslit spectra obtained with ALFOSC at the Nordic Optical Telescope, La Palma. We find that the H$\\alpha$ emission is not related to the primary in $\\beta$ Cep, but is due to its 3.4 magnitudes fainter companion. This companion has been resolved by speckle techniques, but it remains unresolved by traditional spectroscopy. The emission extends fr...

  2. Suma-alpha software description. Study of its applications to detection problems and environmental radioactivity measurements

    International Nuclear Information System (INIS)

    Software named suma-espectros has been developed by TECNASA/CIEMAT for adding counts automatically from the alpha spectra, energy to energy, with the purpose of: evaluating real background of alpha spectrometers, studying its temporal variations, increasing the possibilities of isotopes detection -where it has been impossible to detect due elapsed time of the measurement- and implementing other applications. The programme is written in Visual-Basic and it can export data to Excel spreadsheets for later treatment. The software has established by default a channels range for adding the counts energy by energy but it can be adapted to the analysis of different isotopes and backgrounds simply changing a text file that is incorporated to the programme. The description of the programme management is described for whoever can realise its applications immediately. This software has the advantage of emitting an add-spectrum in cnf format that is used by alpha analyst (Genie 2K) for de convoluting spectra or doing calculations. (Author) 3 refs.

  3. Development and implementation of methodology for radium analysis by alpha spectrometry: preliminary results

    International Nuclear Information System (INIS)

    Alpha spectrometry is one of the most sensitive techniques for radium determination and allows simultaneous measurement of different radium isotopes. The determination of alpha particle-emitting radionuclides in environmental samples by alpha spectrometry requires careful chemical procedures to obtain enough thin sources to provide high quality spectra in which well separated peaks appear. Therefore, determinations by α- spectrometry require radiochemical separation of the element from the matrix, followed by preparation of suitable radioactive sources to obtain high resolution α-spectra in order to minimize peak overlap, and the use of appropriate tracers to determine the chemical yields of the radiochemical sample processing. In this paper, a radiochemical procedure is been developed to 228Ra, 226Ra and 224Ra determination in geological samples, such as rocks, soils, sediments, and waters. The main aim is to include an additional and simple step for the purification of radium within general procedure commonly used in our laboratory for uranium and thorium isotope determination in geological samples. For that reason, we are making several experiments involving direct 226Ra tracer electrodeposition onto stainless steel, as well as ion-exchange chromatography using 225Ra (T1/2 = 14.9 days) as yield tracer. Results showed that chemical recovery of direct electrodeposition of ten aliquots varied between 97 ± 4 % and 104 ± 5 %, with a mean value of 100 ± 1 %, implying in a very small loss in this step. (author)

  4. The influence of salt aerosol on alpha radiation detection by WIPP continuous air monitors

    International Nuclear Information System (INIS)

    Alpha continuous air monitors (CAMs) will be used at the Waste Isolation Pilot Plant (WIPP) to measure airborne transuranic radioactivity that might be present in air exhaust or in work-place areas. WIPP CAMs are important to health and safety because they are used to alert workers to airborne radioactivity, to actuate air-effluent filtration systems, and to detect airborne radioactivity so that the radioactivity can be confined in a limited area. In 1993, the Environmental Evaluation Group (EEG) reported that CAM operational performance was affected by salt aerosol, and subsequently, the WIPP CAM design and usage were modified. In this report, operational data and current theories on aerosol collection were reviewed to determine CAM quantitative performance limitations. Since 1993, the overall CAM performance appears to have improved, but anomalous alpha spectra are present when sampling-filter salt deposits are at normal to high levels. This report shows that sampling-filter salt deposits directly affect radon-thoron daughter alpha spectra and overall monitor efficiency. Previously it was assumed that aerosol was mechanically collected on the surface of CAM sampling filters, but this review suggests that electrostatic and other particle collection mechanisms are more important than previously thought. The mechanism of sampling-filter particle collection is critical to measurement of acute releases of radioactivity. 41 refs

  5. Isolated Photons at Hadron Colliders at O($\\alpha alpha_s^2$) (I): Spin Averaged Case

    OpenAIRE

    Gordon, L. E.

    1996-01-01

    The cross sections for isolated and non-isolated prompt photon production with unpolarized hadron beams are studied at order $\\alpha\\alpha_s^2$. Two methods of performing the calculations are compared. One uses purely analytic techniques and the second uses a combination of analytic and Monte Carlo techniques to perform the phase-space integrations. The results of the analytic and Monte Carlo methods are compared both before and after isolation cuts are placed on the photon. Fragmentation con...

  6. Lambda alpha, Sigma alpha and Xi alpha potentials derived from the SU6 quark-model baryon-baryon interaction

    CERN Document Server

    Fujiwara, Y; Suzuki, Y

    2006-01-01

    We calculate Lambda alpha, Sigma alpha and Xi alpha potentials from the nuclear-matter G-matrices of the SU6 quark-model baryon-baryon interaction. The alpha-cluster wave function is assumed to be a simple harmonic-oscillator shell-model wave function. A new method is proposed to derive the direct and knock-on terms of the interaction Born kernel from the hyperon-nucleon G-matrices, with explicit treatments of the nonlocality and the center-of-mass motion between the hyperon and alpha. We find that the SU6 quark-model baryon-baryon interactions, FSS and fss2, yield a reasonable bound-state energy for 5 He Lambda, -3.18 -- -3.62 MeV, in spite of the fact that they give relatively large depths for the Lambda single-particle potentials, 46 -- 48 MeV, in symmetric nuclear matter. An equivalent local potential derived from the Wigner transform of the nonlocal Lambda alpha kernel shows a strong energy dependence for the incident Lambda-particle, indicating the importance of the strangeness-exchange process in the o...

  7. Thermal Emission and Albedo Spectra of Super Earths with Flat Transmission Spectra

    CERN Document Server

    Morley, Caroline V; Marley, Mark S; Zahnle, Kevin; Line, Michael; Kempton, Eliza; Lewis, Nikole; Cahoy, Kerri

    2015-01-01

    Planets larger than Earth and smaller than Neptune are some of the most numerous in the galaxy, but observational efforts to understand this population have proved challenging because optically thick clouds or hazes at high altitudes obscure molecular features (Kreidberg et al. 2014b). We present models of super Earths that include thick clouds and hazes and predict their transmission, thermal emission, and reflected light spectra. Very thick, lofted clouds of salts or sulfides in high metallicity (1000x solar) atmospheres create featureless transmission spectra in the near-infrared. Photochemical hazes with a range of particle sizes also create featureless transmission spectra at lower metallicities. Cloudy thermal emission spectra have muted features more like blackbodies, and hazy thermal emission spectra have emission features caused by an inversion layer at altitudes where the haze forms. Close analysis of reflected light from warm (~400-800 K) planets can distinguish cloudy spectra, which have moderate ...

  8. Neutron flux density and secondary-particle energy spectra at the 184-inch synchrocyclotron medical facility

    International Nuclear Information System (INIS)

    Helium ions, with an energy of 920 MeV, produced by the 184-inch synchrocyclotron of the Lawrence Berkeley Laboratory are now being used in a pilot series to determine their efficacy in the treatment of tumors of large volume. The techniques for production of the large uniform radiation fields required for these treatments involve the use of beam-limiting collimators and energy degraders. Interaction of the primary beam with these beam components produces secondary charged particles and neutrons. The sources of neutron production in the beam transport system of the alpha-particle beam have been identified and their magnitudes have been determined. Measurements with activation detectors and pulse counters of differing energy responses have been used to determine secondary particle spectra at various locations on the patient table. These spectra are compared to a calculation of neutron production based on best estimates derived from published cross sections. Agreement between the calculated spectra and those derived from experimental measurements is obtained (at the 10 to 20% level) when the presence of charged particles is taken into account. The adsorbed dose in soft tissue is not very sensitive to the shape of the incident neutron energy spectrum, and the values obtained from unfolding the experimental measurements agree with the values obtained from the calculated spectra within the estimated uncertainty of +-25%. These values are about 3 x 10-3 rad on the beam axis and about 1 x 10-3 rad at 20 cm or more from the beam axis, per rad deposited by the incident alpha-particle beam. Estimates of upper limit dose to the lens of the eye and red bone marrow are approximately 10 rad and approximately 1 rad, respectively, for a typical treatment plan. The absorbed dose to the lens of the eye is thus well below the threshold value for cataractogenesis estimated for fission neutrons. An upper limit for the risk of leukemia is estimated to be approximately 0.04%

  9. Level Density Parameter: A Tool to Study the Particle Spectra

    International Nuclear Information System (INIS)

    The compound nucleus 76Kr* is formed in the heavy-ion fusion reactions by an asymmetric entrance channel 12C+64Zn and the symmetric entrance channel 31P+45Sc at the excitation energy of 75 MeV and angular momentum of 39 η. Neutron energy spectra of the asymmetric system (12C+64Zn) at different angles are well described by the statistical model predictions using the normal value of the level density parameter a = A/8 MeV-1. However, in the case of the symmetric system (31P+45Sc), the statistical model interpretation of the data requires the change in the value of a = A/10 MeV-1. The delayed evolution of the compound system in case of the symmetric 31P+45Sc system may lead to the formation of a temperature equilibrated dinuclear complex, which may be responsible for the neutron emission at higher temperature, while the protons and alpha particles are evap orated after neutron emission when the system is sufficiently cooled down and the higher λ-values do not contribute in the formation of the compound nucleus for the symmetric entrance channel in case of charged particle emission.

  10. M Dwarf Flares from Time-Resolved SDSS Spectra

    CERN Document Server

    Hilton, Eric J; Hawley, Suzanne L; Kowalski, Adam F

    2010-01-01

    We have identified 63 flares on M dwarfs from the individual component spectra in the Sloan Digital Sky Survey using a novel measurement of emission line strength called the Flare Line Index. Each of the ~38,000 M dwarfs in the SDSS low mass star spectroscopic sample of West et al. was observed several times (usually 3-5) in exposures that were typically 9-25 minutes in duration. Our criteria allowed us to identify flares that exhibit very strong H-alpha and H-beta emission line strength and/or significant variability in those lines throughout the course of the exposures. The flares we identified have characteristics consistent with flares observed by classical spectroscopic monitoring. The flare duty cycle for the objects in our sample is found to increase from 0.02% for early M dwarfs to 3% for late M dwarfs. We find that the flare duty cycle is larger in the population near the Galactic plane and that the flare stars are more spatially restricted than the magnetically active but non-flaring stars. This sug...

  11. Lattice measurement of \\alpha_s with a realistic charm quark

    CERN Document Server

    Blossier, B; Brinet, M; De Soto, F; Du, X; Morenas, V; Pene, O; Petrov, K; Rodriguez-Quintero, J

    2012-01-01

    We report on an estimate of \\alpha_s, renormalised in the MSbar scheme at the tau and Z^0 mass scales, by means of lattice QCD. Our major improvement compared to previous lattice calculations is that, for the first time, no perturbative treatment at the charm threshold has been required since we have used statistical samples of gluon fields built by incorporating the vacuum polarisation effects of u/d, s and c sea quarks. Extracting \\alpha_s in the Taylor scheme from the lattice measurement of the ghost-ghost-gluon vertex, we obtain \\alpha_s^{MSbar}(m^2_Z)=0.1200(14) and \\alpha_s^{MSbar}(m^2_tau)=0.339(13).

  12. An alpha-omega-dynamo with an alpha-effect due to magnetostrophic waves

    Science.gov (United States)

    Schmitt, D.

    1987-03-01

    The effects of the latitude dependence of the dynamic alpha-effect on the solution of equations of alpha-omega-dynamos are investigated. The equations of kinematic rotationally symmetric alpha-omega-dynamos are evaluated using the spherical solar dynamo model of Deinzer and Stix (1971), in which the induction effects, differential rotation, and alpha-effect act in two separate infinitesimal thin shells. Butterfly diagrams are derived and analyzed. It is observed that the diagram has two branches: the ordinary sunspot branch, migrating from midlatitudes toward the equator during the cycle, and the polar branch, which migrates from the midlatitudes toward the pole. It is also found that, in order to obtain the correct propagation direction of the two dynamos, the alpha of the magnetostrophic waves requires a rotation decreasing with depth. The influence of various locations of the induction layers of alpha- and omega-effect are examined.

  13. Energy dependence of event shapes and of $\\alpha_s$ at LEP 2

    CERN Document Server

    Abreu, P; Adye, T; Adzic, P; Albrecht, Z; Alderweireld, T; Alekseev, G D; Alemany, R; Allmendinger, T; Allport, P P; Almehed, S; Amaldi, Ugo; Amapane, N; Amato, S; Anassontzis, E G; Andersson, P; Andreazza, A; Andringa, S; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbiellini, Guido; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Beillière, P; Belokopytov, Yu A; Belous, K S; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Bizouard, M A; Bloch, D; Blom, H M; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Boyko, I; Bozovic, I; Bozzo, M; Branchini, P; Brenke, T; Brenner, R A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschbeck, Brigitte; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cieslik, K; Collins, P; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crépé, S; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Dris, M; Duperrin, A; Durand, J D; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Ellert, M; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Fayot, J; Feindt, Michael; Fenyuk, A; Ferrari, P; Ferrer, A; Ferrer-Ribas, E; Ferro, F; Fichet, S; Firestone, A; Flagmeyer, U; Föth, H; Fokitis, E; Fontanelli, F; Franek, B J; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gamblin, S; Gandelman, M; García, C; Gaspar, C; Gaspar, M; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Ghodbane, N; Gil, I; Glege, F; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; González-Caballero, I; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Grahl, J; Graziani, E; Green, C; Grimm, H J; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Haider, S; Hallgren, A; Hamacher, K; Hansen, J; Harris, F J; Hedberg, V; Heising, S; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hughes, G J; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, P E; Joram, C; Juillot, P; Kapusta, F; Karafasoulis, K; Katsanevas, S; Katsoufis, E C; Keränen, R; Kersevan, Borut P; Khomenko, B A; Khovanskii, N N; Kiiskinen, A P; King, B J; Kinvig, A; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Kokkinias, P; Koratzinos, M; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Krammer, Manfred; Kriznic, E; Krstic, J; Krumshtein, Z; Kubinec, P; Kurowska, J; Kurvinen, K L; Lamsa, J; Lane, D W; Langefeld, P; Lapin, V; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Leinonen, L; Leisos, A; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; Lopes, J H; López, J M; López-Fernandez, R; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Mahon, J R; Maio, A; Malek, A; Malmgren, T G M; Maltezos, S; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Masik, J; Mazzucato, F; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Meroni, C; Meyer, W T; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Moch, M; Møller, R; Mönig, K; Monge, M R; Moreau, X; Morettini, P; Morton, G A; Müller, U; Münich, K; Mulders, M; Mulet-Marquis, C; Muresan, R; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Nassiakou, M; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neufeld, N; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolenko, M; Nomokonov, V P; Normand, Ainsley; Nygren, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Österberg, K; Ouraou, A; Paganoni, M; Paiano, S; Pain, R; Paiva, R; Palacios, J; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Pegoraro, M; Peralta, L; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Ratoff, P N; Read, A L; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Royon, C; Ruhlmann-Kleider, V; Ruiz, A; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sampsonidis, D; Sannino, M; Schneider, H; Schwemling, P; Schwering, B; Schwickerath, U; Schyns, M A E; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Sekulin, R L; Shellard, R C; Sheridan, A; Siebel, M; Simard, L C; Simonetto, F; Sissakian, A N; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sopczak, André; Sosnowski, R; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stanic, S; Stevenson, K; Stocchi, A; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tegenfeldt, F; Terranova, F; Thomas, J; Timmermans, J; Tinti, N; Tkatchev, L G; Todorova-Nová, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tzamarias, S; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Van Lysebetten, A; Van Vulpen, I B; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Verzi, V; Vilanova, D; Vitale, L; Vlasov, E; Vodopyanov, A S; Vollmer, C F; Voulgaris, G; Vrba, V; Wahlen, H; Walck, C; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G R; Winter, M; Witek, M; Wolf, G; Yi, J; Yushchenko, O P; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G

    1999-01-01

    Infrared and collinear safe event shape distributions and their mean values are determined using the data taken at ve di erent centre of mass energies above $M_Z$ with the DELPHI detector at LEP. From the event shapes, the strong coupling $\\alpha_s$ is extracted in $O(\\alpha^2_s)$, NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well as using an analytical power ansatz. Comparing these measurements to those obtained at MZ, the energy dependence (running) of $\\alpha_s$ is accessible. The logarithmic energy slope of the inverse strong coupling is measured to be $d\\alpha_{s}^{-1}/d log(E_{cm}) = 1.39 \\pm 0.34(stat) \\pm 0.17(syst)$, in good agreement with the QCD expectation of 1.27.

  14. Perturbative expansion of tau hadronic spectral function moments and alpha_s extractions

    CERN Document Server

    Beneke, Martin; Jamin, Matthias

    2012-01-01

    Various moments of the hadronic spectral functions have been employed in the determination of the strong coupling alpha_s from tau decays. In this work we study the behaviour of their perturbative series under different assumptions for the large-order behaviour of the Adler function, extending previous work on the tau hadronic width. We find that the moments can be divided into a small number of classes, whose characteristics depend only on generic features of the moment weight function and Adler function series. Some moments that are commonly employed in alpha_s analyses from tau decays should be avoided because of their perturbative instability. This conclusion is corroborated by a simplified alpha_s extraction from individual moments. Furthermore, under reasonable assumptions for the higher-order behaviour of the perturbative series, fixed-order perturbation theory (FOPT) provides the preferred framework for the renormalization group improvement of all moments that show good perturbative behaviour. Finally...

  15. On Cronbach’s Alpha as the Mean of All Possible k-Split Alphas

    Directory of Open Access Journals (Sweden)

    Matthijs J. Warrens

    2014-01-01

    Full Text Available Coefficient alpha is the most commonly used internal consistency reliability coefficient. Alpha is the mean of all possible k-split alphas if the items are divided into k parts of equal size. This result gives proper interpretations of alpha: interpretations that also hold if (some of its assumptions are not valid. Here we consider the cases where the items cannot be split into parts of equal size. It is shown that if a k-split is made such that the items are divided as evenly as possible, the difference between alpha and the mean of all possible k-split alphas can be made arbitrarily small by increasing the number of items.

  16. An alpha-glucan elicitor from the cell wall of a biocontrol binucleate Rhizoctonia isolate.

    Science.gov (United States)

    Wolski, Erika A; Lima, Carlos; Agusti, Rosalía; Daleo, Gustavo R; Andreu, Adriana B; de Lederkremer, Rosa M

    2005-03-21

    Binucleate Rhizoctonia (BNR) isolate (232-C6) is an effective biocontrol agent for protection of potato from Rhizoctonia canker, a disease caused by Rhizoctonia solani. Production of hydrolytic enzymes is one of the best known inducible defense responses following microbial infection. We isolated and characterized a cell wall alpha-glucan from BNR, which induces beta-1,3 glucanase activities in potato sprouts, the primary site of infection by R. solani. An autoclaving method, previously reported for isolation of oligosaccharide elicitors was used, and the glucan purified by chromatographic techniques. Maximal induction of beta-1,3 glucanase activity in potato sprouts was obtained with 250 microg of the alpha-glucan elicitor after 6 days from inoculation time. Both, BNR mycelium and the alpha-glucan produced a similar kinetic response of beta-1,3 glucanase. However, the alpha-glucan did not induce phytoalexin accumulation, previously correlated with the defense response. Uronic acids (approximately 10% with respect to total neutral sugars) were determined and identified as glucuronic acid by high-pH anion-exchange chromatography. Methylation analysis showed that the glucan consists of (1-->3) and (1-->4)-linked glucose units with preponderance of the first ones. Some of the (1-->4) linkages were branched at position 6. The glucan was partially degraded with amyloglucosidase. This, together with the NMR spectra data and the high optical rotation of the original (+195 degrees ) and degraded glucans (+175 degrees ) proved the alpha configuration. Further methylation of the amyloglucosidase degraded glucans indicated that they consist of (1-->3)-linked glucoses. The present study is the first report on the isolation and characterization of an alpha-glucan from Rhizoctonia, that may be important as a biocontrol factor. PMID:15721332

  17. Brain-wide slowing of spontaneous alpha rhythms in mild cognitive impairment

    Directory of Open Access Journals (Sweden)

    Pilar Garcés

    2013-12-01

    Full Text Available The neurophysiological changes associated with Alzheimer’s Disease (AD and Mild Cognitive Impairment (MCI include an increase in low frequency activity, as measured with electroencephalography or magnetoencephalography (MEG. A relevant property of spectral measures is the alpha peak, which corresponds to the dominant alpha rhythm. Here we studied the spatial distribution of MEG resting state alpha peak frequency and amplitude values in a sample of 27 MCI patients and 24 age-matched healthy controls. Power spectra were reconstructed in source space with linearly constrained minimum variance beamformer. Then, 88 Regions of Interest (ROIs were defined and an alpha peak per ROI and subject was identified. Statistical analyses were performed at every ROI, accounting for age, sex and educational level. Peak frequency was significantly decreased (p< 0.05 in MCIs in many posterior ROIs. The average peak frequency over all ROIs was 9.68±0.71 Hz for controls and 9.05±0.90 Hz for MCIs and the average normalized amplitude was (2.57±0.59•10-2 for controls and (2.70±0.49•10-2 for MCIs. Age and gender were also found to play a role in the alpha peak, since its frequency was higher in females than in males in posterior ROIs and correlated negatively with age in frontal ROIs. Furthermore, we examined the dependence of peak parameters with hippocampal volume, which is a commonly used marker of early structural AD-related damage. Peak frequency was positively correlated with hippocampal volume in many posterior ROIs. Overall, these findings indicate a pathological alpha slowing in MCI.

  18. T-branes and $\\alpha'$-corrections

    CERN Document Server

    Marchesano, Fernando

    2016-01-01

    We study $\\alpha'$-corrections in multiple D7-brane configurations with non-commuting profiles for their transverse position fields. We focus on T-brane systems, crucial in F-theory GUT model building. There $\\alpha'$-corrections modify the D-term piece of the BPS equations which, already at leading order, require a non-primitive Abelian worldvolume flux background. We find that $\\alpha'$-corrections may either i) leave this flux background invariant, ii) modify the Abelian non-primitive flux profile, or iii) deform it to a non-Abelian profile. The last case typically occurs when primitive fluxes, a necessary ingredient to build 4d chiral models, are added to the system. We illustrate these three cases by solving the $\\alpha'$-corrected D-term equations in explicit examples, and describe their appearance in more general T-brane backgrounds. Finally, we discuss implications of our findings for F-theory GUT local models.

  19. Alpha decay property of Pb parent

    International Nuclear Information System (INIS)

    In this work, the half-lives of alpha decay have been calculated from 182-210Pb nuclei, both in two sphere approximation and taking care the deformation effects and compared with the available theoretical and experimental data

  20. Alpha particles spectrometer with photodiode PIN

    International Nuclear Information System (INIS)

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  1. Solar Imagery - Chromosphere - H-Alpha

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of H-alpha photographic datasets contributed by a number of national and private solar observatories located worldwide. Solar...

  2. Neutron-induced alpha radiography

    International Nuclear Information System (INIS)

    A new radiography technique to inspect thin samples was developed. Low energy alpha particles, generated by a boron based screen under thermal neutron irradiation, are used as penetrating radiation. The solid state nuclear track detector CR-39 has been used to register the image. The interaction of the α - particles with the CR-39 gives rise to damages which under an adequate chemical etching became tracks the basic units forming the image. A digital system was developed for data acquisition and data analysis as well as for image processing. The irradiation and etching conditions to obtain the best radiography are 1,3 hours and 25 minutes at 70 deg C respectively. For such conditions samples having 10 μm in thickness can be inspected with a spatial resolution of 32 μm. The use of the digital system has reduced the time spent for data acquisition and data analysis and has improved the radiography image visualization. Furthermore, by using the digital system, it was possible to study several new parameters regarding the tracks which are very important to understand and study the image formation theory in solid state nuclear track detectors, the one used in this thesis. Some radiography images are also shown which demonstrate the potential of the proposed radiography technique. When compared with the other radiography techniques already in use to inspect thin samples, the present one developed in the present paper allows a smaller time to obtain the image, it is not necessary to handle liquid radioactive substances, the detector is insensitive to β, γ, X-ray and visible light. (author)

  3. [Study on the infrared spectra and raman spectra of steel rusty layer with atmospheric corrosion].

    Science.gov (United States)

    Yang, Xiao-mei

    2006-12-01

    In the present study two methods, infrared and Raman spectral analyses, were used to measure the rusty layer of samples with atmospheric corrosion from Qingdao. The main component rust phase of the rusty layer was observed, showing that the relative content of the rust phase varies with the change in corrosion time. The main component rust phases of the rusty layer were found to be alpha-Fe2O3 , gamma-FeOOH, alpha-FeOOH, delta-FeOOH and Fe3O4, with the relative content of each rust phase of A3 (1) rusty layer sample exhibiting the following relation: gamma-FeOOH> alpha-FeOOH>delta-FeOOH, and the relative contents of other rusty layer samples were found to follow the relation: gamma-FeOOH> delta-FeOOH>alpha-FeOOH. PMID:17361722

  4. A Survey for H-alpha Emission from Late L dwarfs and T dwarfs

    CERN Document Server

    Pineda, J Sebastian; Kirkpatrick, J Davy; Cotter, Garret; Kao, Melodie M; Mooley, Kunal

    2016-01-01

    Recently, studies of brown dwarfs have demonstrated that they possess strong magnetic fields and have the potential to produce radio and optical auroral emissions powered by magnetospheric currents. This emission provides the only window on magnetic fields in the coolest brown dwarfs and identifying additional benchmark objects is key to constraining dynamo theory in this regime. To this end, we conducted a new red optical (6300 - 9700 Angstrom) survey with the Keck telescopes looking for H-alpha emission from a sample of late L dwarfs and T dwarfs. Our survey gathered optical spectra for 29 targets, 18 of which did not have previous optical spectra in the literature, greatly expanding the number of moderate resolution (R~2000) spectra available at these spectral types. Combining our sample with previous surveys, we confirm an H-alpha detection rate of 9.2 (+3.5/-2.1) % for L and T dwarfs in the optical spectral range of L4 - T8. This detection rate is consistent with the recently measured detection rate for ...

  5. The AMBRE Project: Stellar Parameterisation of the ESO:UVES archived spectra

    CERN Document Server

    Worley, C C; Recio-Blanco, A; Hill, V; Bijaoui, A

    2016-01-01

    The AMBRE Project is a collaboration between the European Southern Observatory (ESO) and the Observatoire de la Cote d'Azur (OCA) that has been established in order to carry out the determination of stellar atmospheric parameters for the archived spectra of four ESO spectrographs. The analysis of the UVES archived spectra for their stellar parameters has been completed in the third phase of the AMBRE Project. From the complete ESO:UVES archive dataset that was received covering the period 2000 to 2010, 51921 spectra for the six standard setups were analysed. The AMBRE analysis pipeline uses the stellar parameterisation algorithm MATISSE to obtain the stellar atmospheric parameters. The synthetic grid is currently constrained to FGKM stars only. Stellar atmospheric parameters are reported for 12,403 of the 51,921 UVES archived spectra analysed in AMBRE:UVES. This equates to ~23.9% of the sample and ~3,708 stars. Effective temperature, surface gravity, metallicity and alpha element to iron ratio abundances are ...

  6. SPECTRA: An Integrated Knowledge Base for Comparing Tissue and Tumor-Specific PPI Networks in Human.

    Science.gov (United States)

    Micale, Giovanni; Ferro, Alfredo; Pulvirenti, Alfredo; Giugno, Rosalba

    2015-01-01

    Protein-protein interaction (PPI) networks available in public repositories usually represent relationships between proteins within the cell. They ignore the specific set of tissues or tumors where the interactions take place. Indeed, proteins can form tissue-selective complexes, while they remain inactive in other tissues. For these reasons, a great attention has been recently paid to tissue-specific PPI networks, in which nodes are proteins of the global PPI network whose corresponding genes are preferentially expressed in specific tissues. In this paper, we present SPECTRA, a knowledge base to build and compare tissue or tumor-specific PPI networks. SPECTRA integrates gene expression and protein interaction data from the most authoritative online repositories. We also provide tools for visualizing and comparing such networks, in order to identify the expression and interaction changes of proteins across tissues, or between the normal and pathological states of the same tissue. SPECTRA is available as a web server at http://alpha.dmi.unict.it/spectra. PMID:26005672

  7. Post-maximum near infrared spectra of SN 2014J: A search for interaction signatures

    CERN Document Server

    Sand, D J; Banerjee, D P K; Marion, G H; Diamond, T R; Joshi, V; Parrent, J T; Phillips, M M; Stritzinger, M D; Venkataraman, V

    2016-01-01

    We present near infrared (NIR) spectroscopic and photometric observations of the nearby Type Ia SN 2014J. The seventeen NIR spectra span epochs from +15.3 to +92.5 days after $B$-band maximum light, while the $JHK_s$ photometry include epochs from $-$10 to +71 days. This data is used to constrain the progenitor system of SN 2014J utilizing the Pa$\\beta$ line, following recent suggestions that this phase period and the NIR in particular are excellent for constraining the amount of swept up hydrogen-rich material associated with a non-degenerate companion star. We find no evidence for Pa$\\beta$ emission lines in our post-maximum spectra, with a rough hydrogen mass limit of $\\lesssim$0.1 $M_{\\odot}$, which is consistent with previous limits in SN 2014J from late-time optical spectra of the H$\\alpha$ line. Nonetheless, the growing dataset of high-quality NIR spectra holds the promise of very useful hydrogen constraints.

  8. Alpha thalassaemia-mental retardation, X linked

    OpenAIRE

    Gibbons Richard

    2006-01-01

    Abstract X-linked alpha thalassaemia mental retardation (ATR-X) syndrome in males is associated with profound developmental delay, facial dysmorphism, genital abnormalities and alpha thalassaemia. Female carriers are usually physically and intellectually normal. So far, 168 patients have been reported. Language is usually very limited. Seizures occur in about one third of the cases. While many patients are affectionate with their caregivers, some exhibit autistic-like behaviour. Patients pres...

  9. Alpha particle spectroscopy by gridded ionization chamber

    International Nuclear Information System (INIS)

    A gridded ionization chamber has been constructed with the aim of determining its ultimate energy resolution in alpha spectroscopy, utilizing a cooled FET pre-amplifier of the type normally employed with semiconductor detectors. With suitable mechanical collimation of the alpha particles, their fine structure has been measured with an energy resolution of -11.5 keV (fwhm), achieved using an Ar + 0.75% C2H2 mixture as the filling gas. (orig.)

  10. Abundances in Damped Ly-alpha Galaxies

    OpenAIRE

    Molaro, Paolo

    2005-01-01

    Damped Ly_alpha galaxies provide a sample of young galaxies where chemical abundances can be derived throughout the whole universe with an accuracy comparable to that for the local universe. Despite a large spread in redshift, HI column density and metallicity, DLA galaxies show a remarkable uniformity in the elemental ratios rather suggestive of similar chemical evolution if not of an unique population. These galaxies are characterized by a moderate, if any, enhancement of alpha-elements ove...

  11. Alpha emitters in Chernobyl hot particles

    International Nuclear Information System (INIS)

    The alpha radioactive component of hot particles from the Chernobyl fallout was analysed for cases studied previously by gamma spectroscopy. Correlations established from the absolute alpha activity determination and high resolution analysis provided information on actinides release during accident and on some aspects of the Chernobyl reactor fuel composition. Unexpected features revealed during the analysis of one specific particle are presented. 11 refs., 5 figs., 5 tabs. (author)

  12. Processing. alpha. -mercuric iodide by zone refining

    Energy Technology Data Exchange (ETDEWEB)

    Burger, A.; Morgan, S.H.; Henderson, D.O.; Biao, Y.; Zhang, K.; Silberman, E. (Fisk Univ., Nashville, TN (United States). Dept. of Physics); Nason, D.; van den Berg, L.; Ortale-Baccash, C.; Cross, E. (EG and G Energy Measurements, Inc., Goleta, CA (United States). Santa Barbara Operations)

    1992-01-01

    An investigation is being conducted on zone refining {alpha}-mercuric iodide. Analytical studies using differential scanning calorimetry and anion chromatography indicate that impurities are segregated mainly at the end where zone travel terminates. Early results indicate that single crystals can be readily grown from zone refined material, and the effects of the process on the performance of radiation detectors fabricated from {alpha}-mercuric iodide are being evaluated.

  13. Phototransferred thermoluminescence and exoemission in alpha alumina

    Energy Technology Data Exchange (ETDEWEB)

    Iacconi, P.; Lapraz, D.; Alessandri-Fraccaro, M.F.; Addi, D. (Univ. de Nice-Sophia Antipolis (France). Lab. d' Emission Electronique et de Luminescence)

    1990-01-01

    {alpha}-Al{sub 2}O{sub 3}, irradiated by ionising radiation and submitted to UV illumination, presents a phototransfer phenomenon that is characterised by thermoluminescence (TL) and by thermostimulated exoelectronic emission (TSEE). The TL and the TSEE glow curves of {alpha}-alumina from -196 to 700{sup 0}C are compared, to parallel one phototransfer observation with another and to draw various conclusions concerning the stability of the traps involved in dosimetric applications. (author).

  14. ON An Infra-\\(\\alpha\\)-Open Sets

    OpenAIRE

    Hakeem Othman; Md Hanif Page

    2016-01-01

    In this paper, we define a new class of set in general topology called an infra- \\(\\alpha\\) open set and we investigate fundamental properties by using this new class. The relation between infra-\\(\\alpha\\)-open set and other topological sets are studied. Moreover, In the light of this new definition, we also define some generalization of continuous mappings and discuss the relations between these new classes of mappings and other continuous mappings. Basic properties of these new mappings...

  15. Neurophysiological assessment of alpha pattern coma.

    OpenAIRE

    Obeso, J A; Iragui, M I; Marti-Masso, J. F.; Maravi, E; Teijeira, J M; Carrera, N; Teijeria, J

    1980-01-01

    Somatosensory evoked potentials, blink reflexes, and H wave reflexes, were recorded on several days from three patients with alpha pattern coma. Coma was secondary to cardiac arrest in two cases and to brainstem infarction in one. Results are compatible with damage to the brainstem reticular formation with sparing of thalamo-cortical circuits as the main physiopathological characteristic of alpha pattern coma. This condition should not be regarded as a discrete entity when establishing the pr...

  16. Alpha-emitters for medical therapy workshop

    Energy Technology Data Exchange (ETDEWEB)

    Feinendegen, L.E.; McClure, J.J.

    1996-12-31

    A workshop on ``Alpha-Emitters for Medical Therapy`` was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference.

  17. Alpha-emitters for medical therapy workshop

    International Nuclear Information System (INIS)

    A workshop on ''Alpha-Emitters for Medical Therapy'' was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference

  18. Remote Associates Test and Alpha Brain Waves

    OpenAIRE

    Haarmann, Henk J.; George, Timothy; Smaliy, Alexei; Dien, Joseph

    2012-01-01

    Previous studies found that performance on the remote associates test (RAT) improves after a period of incubation and that increased alpha brain waves over the right posterior brain predict the emergence of RAT insight solutions. We report an experiment that tested whether increased alpha brain waves during incubation improve RAT performance. Participants received two blocks of RAT items (RAT1 and RAT2), with the second block consisting of items that were not solved during the first block. Pa...

  19. Self-assembling, dynamic alphaPNAs

    DEFF Research Database (Denmark)

    Nielsen, Peter E

    2009-01-01

    In the recent report published in Science, Ghadiri and coworkers describe dynamic tPNAs, alphaPNA derivatives with a nucleobase attached via a thioester bond that are a step forward toward self-repairing and replicating molecules.......In the recent report published in Science, Ghadiri and coworkers describe dynamic tPNAs, alphaPNA derivatives with a nucleobase attached via a thioester bond that are a step forward toward self-repairing and replicating molecules....

  20. Alpha emitters in Chernobyl hot particles

    Energy Technology Data Exchange (ETDEWEB)

    Broda, R.; Kubica, B.; Szeglowski, Z.; Zuber, K. (Institute of Nuclear Physics, Krakow (Poland))

    1989-01-01

    The alpha radioactive component of hot particles from the Chernobyl fallout was analyzed for cases studied previously by gamma spectroscopy. Correlations established from the absolute alpha activity determination and high resolution analysis provided information on the release of actinides during the accident and on some aspects of the Chernobyl reactor fuel composition. Unexpected features revealed during the analysis of one specific particle are presented. (orig.).