2,413 research outputs found
Prospectus, May 3, 1989
https://spark.parkland.edu/prospectus_1989/1010/thumbnail.jp
Water wave propagation and scattering over topographical bottoms
Here I present a general formulation of water wave propagation and scattering
over topographical bottoms. A simple equation is found and is compared with
existing theories. As an application, the theory is extended to the case of
water waves in a column with many cylindrical steps
Misleading signatures of quantum chaos
The main signature of chaos in a quantum system is provided by spectral
statistical analysis of the nearest neighbor spacing distribution and the
spectral rigidity given by . It is shown that some standard
unfolding procedures, like local unfolding and Gaussian broadening, lead to a
spurious increase of the spectral rigidity that spoils the
relationship with the regular or chaotic motion of the system. This effect can
also be misinterpreted as Berry's saturation.Comment: 4 pages, 5 figures, submitted to Physical Review
Prospectus, February 8, 1989
https://spark.parkland.edu/prospectus_1989/1033/thumbnail.jp
Outskirts of Distant Galaxies In Absorption
QSO absorption spectroscopy provides a sensitive probe of both the neutral
medium and diffuse ionized gas in the distant Universe. It extends 21cm maps of
gaseous structures around low-redshift galaxies both to lower gas column
densities and to higher redshifts. Combining galaxy surveys with
absorption-line observations of gas around galaxies enables comprehensive
studies of baryon cycles in galaxy outskirts over cosmic time. This Chapter
presents a review of the empirical understanding of the cosmic neutral gas
reservoir from studies of damped Lya absorbers (DLAs). It describes the
constraints on the star formation relation and chemical enrichment history in
the outskirts of distant galaxies from DLA studies. A brief discussion of
available constraints on the ionized circumgalactic gas from studies of lower
column density Lya absorbers and associated ionic absorption transitions is
presented at the end.Comment: 45 pages, 7 figures, invited review, Book chapter in "Outskirts of
Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and
Space Science Library, Springer, in pres
Prospectus, April 9, 1989
https://spark.parkland.edu/prospectus_1989/1008/thumbnail.jp
Prospectus, April 12, 1989
https://spark.parkland.edu/prospectus_1989/1007/thumbnail.jp
Analytical Treatment of the Oscillating Yukawa Potential
Using a suitable Laguerre basis set that ensures a tridiagonal matrix
representation of the reference Hamiltonian, we were able to evaluate in closed
form the matrix elements of the generalized Yukawa potential with complex
screening parameter. This enabled us to treat analytically both the cosine and
sine-like Yukawa potentials on equal footing and compute their bound states
spectrum as the eigenvalues of the associated analytical matrix representing
their Hamiltonians. Finally we used a carefully designed complex scaling method
to evaluate the resonance energies and compared our results satisfactorily with
those obtained in the literature.Comment: 8 pages 2 table
Delay Claim Analysis in the Construction Industry
Delay claims, a common occurrence in construction projects, result from many issues, including differing site conditions, access restrictions, and disputes of the contract documents. Analysis methods of a delay claim can range from scheduling to cost analysis. Methods in use today can incur exponential costs, and can last for years on end. Using a survey, this study collected the data regarding practices in delay claim analysis from professionals within the construction industry. The survey emphasized the defining qualities of a delay claim, the processes, and the requirements for resolving a claim. The results showed that the analysis of schedules and other contract documents were major resources when analyzing and resolving a delay claim. The top three subcontractors who submitted the most delay claims are concrete, earthwork, and steel
Proposed minimal standards for the use of genome data for the taxonomy of prokaryotes
Advancement of DNA sequencing technology allows the routine use of genome sequences in the various fields of microbiology. The information held in genome sequences proved to provide objective and reliable means in the taxonomy of prokaryotes. Here, we describe the minimal standards for the quality of genome sequences and how they can be applied for taxonomic purposes
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