55,407 research outputs found
Random Matrices and Chaos in Nuclear Physics: Nuclear Reactions
The application of random-matrix theory (RMT) to compound-nucleus (CN)
reactions is reviewed. An introduction into the basic concepts of nuclear
scattering theory is followed by a survey of phenomenological approaches to CN
scattering. The implementation of a random-matrix approach into scattering
theory leads to a statistical theory of CN reactions. Since RMT applies
generically to chaotic quantum systems, that theory is, at the same time, a
generic theory of quantum chaotic scattering. It uses a minimum of input
parameters (average S-matrix and mean level spacing of the CN). Predictions of
the theory are derived with the help of field-theoretical methods adapted from
condensed-matter physics and compared with those of phenomenological
approaches. Thorough tests of the theory are reviewed, as are applications in
nuclear physics, with special attention given to violation of symmetries
(isospin, parity) and time-reversal invariance.Comment: 50 pages, 26 figure
The Thousand Aviator Study - Smoking history correlates of selected physiological, biochemical, and anthropometric measures
Smoking history correlates of selected physiological, biochemical, and anthropometric measure
Incorporation of superlattice crystal layers in multijunction solar cells
Superlattice layers are effective in decreasing the density of dislocations in lattice mismatched heterostructures at least four orders of magnitude. Hence it was proposed to utilize this feature of superlattices to alleviate the problems due to misfit dislocations generated in the regions between two or more photovoltaic collecting junctions. A further advantage is that the possibility is presented for using silicon as a low cost substrate as well as for the low band gap junction. In the test case, a silicon low gap cell was connected to a GaAs.7P.3 high gap cell through a connecting region containing a GaAs/GaP superlattice
Thousand Aviator Study - Nonvestibular Contributions to Postural Equilibrium Functions
Psychomotor performance and postural equilibrium functioning defined by quantitative ataxia test battery, and relation to pilot selection and gerontolog
Archetypal analysis of galaxy spectra
Archetypal analysis represents each individual member of a set of data
vectors as a mixture (a constrained linear combination) of the pure types or
archetypes of the data set. The archetypes are themselves required to be
mixtures of the data vectors. Archetypal analysis may be particularly useful in
analysing data sets comprising galaxy spectra, since each spectrum is,
presumably, a superposition of the emission from the various stellar
populations, nebular emissions and nuclear activity making up that galaxy, and
each of these emission sources corresponds to a potential archetype of the
entire data set. We demonstrate archetypal analysis using sets of composite
synthetic galaxy spectra, showing that the method promises to be an effective
and efficient way to classify spectra. We show that archetypal analysis is
robust in the presence of various types of noise.Comment: 6 pages, 5 figures, 1 style-file. Accepted for publication by MNRA
Factors contributing to the ballistocardiographic wave form in healthy middle aged males
Factors contributing to ballistocardiographic waveform in healthy middle aged male
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