371 research outputs found
Accuracy of Trace Formulas
Using quantum maps we study the accuracy of semiclassical trace formulas. The
role of chaos in improving the semiclassical accuracy, in some systems, is
demonstrated quantitatively. However, our study of the standard map cautions
that this may not be most general. While studying a sawtooth map we demonstrate
the rather remarkable fact that at the level of the time one trace even in the
presence of fixed points on singularities the trace formula may be exact, and
in any case has no logarithmic divergences observed for the quantum bakers map.
As a byproduct we introduce fantastic periodic curves akin to curlicues.Comment: 20 pages, uuencoded and gzipped, 1 LaTex text file and 9 PS files for
figure
Cyclic Identities Involving Jacobi Elliptic Functions. II
Identities involving cyclic sums of terms composed from Jacobi elliptic
functions evaluated at equally shifted points on the real axis were
recently found. These identities played a crucial role in discovering linear
superposition solutions of a large number of important nonlinear equations. We
derive four master identities, from which the identities discussed earlier are
derivable as special cases. Master identities are also obtained which lead to
cyclic identities with alternating signs. We discuss an extension of our
results to pure imaginary and complex shifts as well as to the ratio of Jacobi
theta functions.Comment: 38 pages. Modified and includes more new identities. A shorter
version of this will appear in J. Math. Phys. (May 2003
Using the Hadamard and related transforms for simplifying the spectrum of the quantum baker's map
We rationalize the somewhat surprising efficacy of the Hadamard transform in
simplifying the eigenstates of the quantum baker's map, a paradigmatic model of
quantum chaos. This allows us to construct closely related, but new, transforms
that do significantly better, thus nearly solving for many states of the
quantum baker's map. These new transforms, which combine the standard Fourier
and Hadamard transforms in an interesting manner, are constructed from
eigenvectors of the shift permutation operator that are also simultaneous
eigenvectors of bit-flip (parity) and possess bit-reversal (time-reversal)
symmetry.Comment: Version to appear in J. Phys. A. Added discussions; modified title;
corrected minor error
Involvement of Serine Threonine Protein Kinase, PknL, from Mycobacterium Tuberculosis H37Rv in Starvation Response of Mycobacteria
The adaptation to nutrient depletion in bacteria involves
a highly organized series of intracellular events that enable
them to adapt to starvation conditions. The regulatory
effect of serine threonine protein kinase, PknL, from
Mycobacterium tuberculosis strain H37Rv was investigated
under nutrient deprived conditions that simulate circumstances
leading to latency. Recombinant PknL was expressed
in Mycobacterium smegmatis strain mc2155 in its
wild type and mutant forms. In vitro growth kinetics experiments
revealed that clone expressing active PknL had
a significant growth advantage under nutrient limiting
conditions. Experiments were conducted to ascertain the
in silico predictions of the involvement of PknL in regulating
glutamine metabolism in mycobacteria. Furthermore,
a role for PknL in cell wall biogenesis/cell division
was shown by scanning electron microscopy
An Economic and Environmental Evaluation of Farm Bill Policy Options Using the CEEPES-FAPRI Modeling System
This report estimates the economic and environmental trade-offs of the 1995 Farm Bill policy options evaluated by FAPRI. Assessments are provided for the 1995 FAPRI baseline, 25 percent Normal Flex, and the Revenue Assurance program. The authors describe the modeling systems and the CEEPES-FAPRI linkage, delineate the policy options and their likely economic and environmental impacts, and discuss predicted economic and environmental impacts of these policy options
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