18,176 research outputs found
Invalidity of Classes of Approximated Hall Effect Calculations
In this comment, I point out a number of approximated derivations for the
effective equation of motion, now been applied to d-wave superconductors by
Kopnin and Volovik are invalid. The major error in those approximated
derivations is the inappropriate use of the relaxation time approximation in
force-force correlation functions, or in force balance equations, or in similar
variations. This approximation is wrong and unnecessary.Comment: final version, minor changes, to appear in Phys. Rev. Let
Calculating Biological Behaviors of Epigenetic States in Phage lambda Life Cycle
Gene regulatory network of lambda phage is one the best studied model systems
in molecular biology. More 50 years of experimental study has provided a
tremendous amount of data at all levels: physics, chemistry, DNA, protein, and
function. However, its stability and robustness for both wild type and mutants
has been a notorious theoretical/mathematical problem. In this paper we report
our successful calculation on the properties of this gene regulatory network.
We believe it is of its first kind. Our success is of course built upon
numerous previous theoretical attempts, but following 3 features make our
modeling uniqu:
1) A new modeling method particular suitable for stability and robustness
study;
2) Paying a close attention to the well-known difference of in vivo and in
vitro;
3) Allowing more important role for noise and stochastic effect to play.
The last two points have been discussed by two of us (Ao and Yin,
cond-mat/0307747), which we believe would be enough to make some of previous
theoretical attempts successful, too. We hope the present work would stimulate
a further interest in the emerging field of gene regulatory network.Comment: 16 pages, 3 figures, 1 tabl
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