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Crackling noise peaks as signature of avalanche correlation
No full textUntil now, all existing theories failed to explain peaks in the power noise spectra. Here we focus on the role of correlation among avalanches as the main source of the noise peaks observed. The present theory is based on first principles statistics of elementary events clustered in time-amplitude correlated avalanches. A noise spectral power master equation suitable to explain any peaked noise spectra is analytically achieved. Excellent agreement with our noise experiments in superconductors and with recent experiments in Escherichia coli, in single DNA molecule, and in single electron tunneling is reporte
Votrex avalanche phenomena in MgB2 superconducting film studied by current noise measurements
No full textVortex avalanche phenomenon enhanced by thermomagnetic instabilities suppresses critical current in MgB2 films. This effect is investigated at 4.2 K by spectral noise power measurements up to 1 kHz with a dc superconducting quantum interference device apparatus. 1/f(gamma) behavior is shown at low frequencies in magnetic fields and feeding currents below j(c). gamma increases from 1 to 2 at increasing magnetic field, typical of fluxon avalanche processes. A peak in the power spectrum frequency behavior, observed only in magnetic field, is attributed to vortex-antivortex annihilations. Thermal instabilities disappear when an efficient thermal link to the He bath is attained and no vortex avalanche extra-noise is observed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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