16 research outputs found
Excitation of Giant Monopole Resonance in Pb and Sn Using Inelastic Deuteron Scattering
The excitation of the isoscalar giant monopole resonance (ISGMR) in
Sn and Pb has been investigated using small-angle (including
) inelastic scattering of 100 MeV/u deuteron and
multipole-decomposition analysis (MDA). The extracted strength distributions
agree well with those from inelastic scattering of 100 MeV/u
particles. These measurements establish deuteron inelastic scattering at E 100 MeV/u as a suitable probe for extraction of the ISGMR strength with
MDA, making feasible the investigation of this resonance in radioactive
isotopes in inverse kinematics.Comment: 5 pages, 4 figures. To be published in Phys. Lett.
Effect of promoter architecture on the cell-to-cell variability in gene expression
According to recent experimental evidence, the architecture of a promoter,
defined as the number, strength and regulatory role of the operators that
control the promoter, plays a major role in determining the level of
cell-to-cell variability in gene expression. These quantitative experiments
call for a corresponding modeling effort that addresses the question of how
changes in promoter architecture affect noise in gene expression in a
systematic rather than case-by-case fashion. In this article, we make such a
systematic investigation, based on a simple microscopic model of gene
regulation that incorporates stochastic effects. In particular, we show how
operator strength and operator multiplicity affect this variability. We examine
different modes of transcription factor binding to complex promoters
(cooperative, independent, simultaneous) and how each of these affects the
level of variability in transcription product from cell-to-cell. We propose
that direct comparison between in vivo single-cell experiments and theoretical
predictions for the moments of the probability distribution of mRNA number per
cell can discriminate between different kinetic models of gene regulation.Comment: 35 pages, 6 figures, Submitte