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  • Seismology  (2)
  • Cotyledons  (1)
  • 1
    Electronic Resource
    Electronic Resource
    The reserve proteins in the cells of mature cotyledons ofLupinus albus var.Lucky (1986)
    Springer
    Protoplasma 130 (1986), S. 128-137 
    Details
    ISSN: 1615-6102
    Keywords: Cotyledons ; DNA ; Endopolyploidy ; Lupin ; Protein content
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nuclear DNA content of cotyledonary cells of two lupin seeds (L1 and L2) with markedly different total protein content, were investigated by scanning cytophotometry. Both seeds had polyloid nuclei with DNA levels varying between 8 C and 64 C, the majority being either 16 C or 32 C. The highest DNA levels were found in the abaxial and central cotyledonary zones of both seeds; seed L2 had a higher ploidy level than L1. It is shown that the volume of condensed chromatin (chromocenters) increased proportionally with the DNA content of the nucleus. A comparison was made between the distribution of protein, previously determined byLe Gal andRey (1986) and the DNA throughout the cotyledon. The L2 seed, which has the highest total protein and the highest protein content per cell, also exhibited the greatest DNA content per cell. For both seeds, the r-value for association of DNA and protein content per cell was highly significant (0.98).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01276594
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    Paper (German National Licenses)
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  • 2
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    Deconvolution enhanced direction of arrival estimation using one- and three-component seismic arrays applied to ocean induced microseisms (2016)
    Oxford University Press
    Details
    Publication Date: 2016-05-22
    Description: Microseisms in the period of 2–10 s are generated in deep oceans and near coastal regions. It is common for microseisms from multiple sources to arrive at the same time at a given seismometer. It is therefore desirable to be able to measure multiple slowness vectors accurately. Popular ways to estimate the direction of arrival of ocean induced microseisms are the conventional (fk) or adaptive (Capon) beamformer. These techniques give robust estimates, but are limited in their resolution capabilities and hence do not always detect all arrivals. One of the limiting factors in determining direction of arrival with seismic arrays is the array response, which can strongly influence the estimation of weaker sources. In this work, we aim to improve the resolution for weaker sources and evaluate the performance of two deconvolution algorithms, Richardson–Lucy deconvolution and a new implementation of CLEAN-PSF. The algorithms are tested with three arrays of different aperture (ASAR, WRA and NORSAR) using 1 month of real data each and compared with the conventional approaches. We find an improvement over conventional methods from both algorithms and the best performance with CLEAN-PSF. We then extend the CLEAN-PSF framework to three components (3C) and evaluate 1 yr of data from the Pilbara Seismic Array in northwest Australia. The 3C CLEAN-PSF analysis is capable in resolving a previously undetected Sn phase.
    Keywords: Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 3
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    Improved implementation of the fk and Capon methods for array analysis of seismic noise (2014)
    Oxford University Press
    Details
    Publication Date: 2014-06-28
    Description: The frequency–wavenumber (fk) and Capon methods are widely used in seismic array studies of background or ambient noise to infer the backazimuth and slowness of microseismic sources. We present an implementation of these techniques for the analysis of microseisms (0.05–2 Hz) which draws on array signal processing literature from a range of disciplines. The presented techniques avoid frequency mixing in the cross-power spectral density and therefore yield an accurate slowness vector estimation of the incoming seismic waves. Using synthetic data, we show explicitly how the frequency averaged broad-band approach can result in a slowness-shifted spectrum. The presented implementation performs the slowness estimations individually for each frequency bin and sums the resulting slowness spectra over a specific frequency range. This may be termed an incoherently averaged signal, or IAS, approach. We further modify the method through diagonal loading to ensure a robust solution. The synthetic data show good agreement between the analytically derived and inferred error in slowness. Results for real (observed) data are compared between the approximate and IAS methods for two different seismic arrays. The IAS method results in the improved resolution of features, particularly for the Capon spectrum, and enables, for instance, Rg and Lg arrivals from similar backazimuths to be separated in the case of real data.
    Keywords: Seismology
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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    PAPER CURRENT
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