20,645 research outputs found
On the permanent of random Bernoulli matrices
We show that the permanent of an matrix with iid Bernoulli
entries is of magnitude with probability .
In particular, it is almost surely non-zero
Regulation and the neo-Wicksellian approach to monetary policy
Laubach and Williams (2003) employ a Kalman filter approach to jointly estimate the neutral real federal funds rate and trend output growth using an IS relationship and an output gap based inflation equation. They find a positive link between these two variables, but also much error surrounding neutral real rate estimates. We modify their approach by including variables for regulations on deposit interest rates and on wages and prices. These variables are statistically significant and notably affect estimates of two policy relevant coefficients: the sensitivity of output to the real interest rate and that of inflation to the output gap.Monetary policy ; Federal funds rate
Stochastic modeling of regulation of gene expression by multiple small RNAs
A wealth of new research has highlighted the critical roles of small RNAs
(sRNAs) in diverse processes such as quorum sensing and cellular responses to
stress. The pathways controlling these processes often have a central motif
comprising of a master regulator protein whose expression is controlled by
multiple sRNAs. However, the regulation of stochastic gene expression of a
single target gene by multiple sRNAs is currently not well understood. To
address this issue, we analyze a stochastic model of regulation of gene
expression by multiple sRNAs. For this model, we derive exact analytic results
for the regulated protein distribution including compact expressions for its
mean and variance. The derived results provide novel insights into the roles of
multiple sRNAs in fine-tuning the noise in gene expression. In particular, we
show that, in contrast to regulation by a single sRNA, multiple sRNAs provide a
mechanism for independently controlling the mean and variance of the regulated
protein distribution
3D structure of hadrons by generalized distribution amplitudes and gravitational form factors
Generalized distribution amplitudes (GDAs) are one type of three-dimensional
structure functions, and they are related to the generalized distribution
functions (GPDs) by the - crossing of the Mandelstam variables. The GDA
studies provide information on three-dimensional tomography of hadrons. The
GDAs can be investigated by the two-photon process , and the GPDs are studied by the deeply virtual Compton scattering . The GDA studies had been pure theoretical topics, although the
GPDs have been experimentally investigated, because there was no available
experimental measurement. Recently, the Belle collaboration reported their
measurements on the differential cross
section, so that it became possible to find the GDAs from their measurements.
Here, we report our analysis of the Belle data for determining the pion GDAs.
From the GDAs, the timelike gravitational form factors and
can be calculated, which are mechanical (pressure, shear force)
and mass (energy) form factors, respectively. They are converted to the
spacelike form factors by using the dispersion relation, and then gravitational
radii are evaluated for the pion. The mass and mechanical radii are obtained
from and as fm and fm, whereas the experimental charge radius is fm for the charged pion. Future
developments are expected in this new field to explore gravitational physics in
the quark and gluon level.Comment: 6 pages, LaTeX, 1 style file, 8 figure files, Proceedings of the XXV
International Workshop on Deep-Inelastic Scattering and Related Subjects,
April 3-7, 2017, University of Birmingham, U
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