2,409 research outputs found
Simple Combined Model for Nonlinear Excitations in DNA
We propose a new simple model for DNA denaturation bases on the pendulum
model of Englander\cite{A1} and the microscopic model of Peyrard {\it et
al.},\cite{A3} so called "combined model". The main parameters of our model
are: the coupling constant along each strand, the mean stretching
of the hydrogen bonds, the ratio of the damping constant and driven force
. We show that both the length of unpaired bases and the velocity
of kinks depend on not only the coupling constant but also the
temperature . Our results are in good agreement with previous works.Comment: 6 pages, 10 figures, submitted to Phys. Rev.
Bounded Linear Stability Margin Analysis of Nonlinear Hybrid Adaptive Control
This paper presents a bounded linear stability analysis for a hybrid adaptive control that blends both direct and indirect adaptive control. Stability and convergence of nonlinear adaptive control are analyzed using an approximate linear equivalent system. A stability margin analysis shows that a large adaptive gain can lead to a reduced phase margin. This method can enable metrics-driven adaptive control whereby the adaptive gain is adjusted to meet stability margin requirements
Microbial community management in aquaculture
Microbial community management in aquaculture creates benefits at the nutritional as well as at health level for cultured species. In addition, in case of biofloc application, it allows to link species at different trophic levels, making bioflocs the potential link in integrated multispecies aquaculture
Constraining a Model of the Radio Sky Below 6 MHz Using the Parker Solar Probe/FIELDS Instrument in Preparation for Upcoming Lunar-based Experiments
We present a Bayesian analysis of data from the FIELDS instrument on board
the Parker Solar Probe (PSP) spacecraft with the aim of constraining low
frequency ( 6 MHz) sky in preparation for several upcoming
lunar-based experiments. We utilize data recorded during PSP's ``coning roll''
maneuvers, in which the axis of the spacecraft is pointed 45 off of
the Sun. The spacecraft then rotates about a line between the Sun and the
spacecraft with a period of 24 minutes. We reduce the data into two formats:
roll-averaged, in which the spectra are averaged over the roll, and
phase-binned, in which the spectra are binned according to the phase of the
roll. We construct a forward model of the FIELDS observations that includes
numerical simulations of the antenna beam, an analytic emissivity function of
the galaxy, and estimates of the absorption due to free electrons. Fitting 5
parameters, we find that the roll-averaged data can be fit well by this model
and we obtain posterior parameter constraints that are in general agreement
with previous estimates. The model is not, however, able to fit the
phase-binned data well, likely due to limitations such as the lack of
non-smooth emission structure at both small and large scales, enforced symmetry
between the northern and southern galactic hemispheres, and large uncertainties
in the free electron density. This suggests that significant improvement in the
low frequency sky model is needed in order to fully and accurately represent
the sky at frequencies below 6 MHz.Comment: 18 pages, 10 figures, 5 tables. Under review in the Astrophysical
Journa
- …