2,389 research outputs found
A Microscopic Mechanism for Muscle's Motion
The SIRM (Stochastic Inclined Rods Model) proposed by H. Matsuura and M.
Nakano can explain the muscle's motion perfectly, but the intermolecular
potential between myosin head and G-actin is too simple and only repulsive
potential is considered. In this paper we study the SIRM with different complex
potential and discuss the effect of the spring on the system. The calculation
results show that the spring, the effective radius of the G-actin and the
intermolecular potential play key roles in the motion. The sliding speed is
about calculated from the model which well agrees with
the experimental data.Comment: 9 pages, 6 figure
Force Dependence of the Michaelis Constant in a Two-State Ratchet Model for Molecular Motors
We present a quantitative analysis of recent data on the kinetics of ATP
hydrolysis, which has presented a puzzle regarding the load dependence of the
Michaelis constant. Within the framework of coarse grained two-state ratchet
models, our analysis not only explains the puzzling data, but provides a
modified Michaelis law, which could be useful as a guide for future
experiments.Comment: 4 pages, 3 eps figures, accepted for publication on Physical Review
Letter
Alternative student finance : current and future students’ perspectives: Research report, May 2019
Nodal domains of Maass forms I
This paper deals with some questions that have received a lot of attention
since they were raised by Hejhal and Rackner in their 1992 numerical
computations of Maass forms. We establish sharp upper and lower bounds for the
-restrictions of these forms to certain curves on the modular surface.
These results, together with the Lindelof Hypothesis and known subconvex
-bounds are applied to prove that locally the number of nodal domains
of such a form goes to infinity with its eigenvalue.Comment: To appear in GAF
Coexistence of ferromagnetism and superconductivity
A comprehensive theory is developed that describes the coexistence of p-wave,
spin-triplet superconductivity and itinerant ferromagnetism. It is shown how to
use field-theoretic techniques to derive both conventional strong-coupling
theory, and analogous gap equations for superconductivity induced by magnetic
fluctuations. It is then shown and discussed in detail that the magnetic
fluctuations are generically stronger on the ferromagnetic side of the magnetic
phase boundary, which substantially enhances the superconducting critical
temperature in the ferromagnetic phase over that in the paramagnetic one. The
resulting phase diagram is compared with the experimental observations in UGe_2
and ZrZn_2.Comment: 16 pp., REVTeX, 6 eps figs; final version as publishe
Novel features in the flux-flow resistivity of the heavy fermion superconductor PrOsSb
We have investigated the electrical resistivity of the heavy fermion
superconductor PrOsSb in the mixed state. We found unusual double
minima in the flux-flow resistivity as a function of magnetic field below the
upper critical field for the first time, indicating double peaks in the pinning
force density (). Estimated at the peak exhibits
apparent dependence on applied field direction; composed of two-fold and
four-fold symmetries mimicking the reported angular dependence of thermal
conductivity (). The result is discussed in correlation with the double
step superconducting (SC) transition in the specific heat and the multiple
SC-phases inferred from the angular dependence of .Comment: 5 pages, 7 figures, to appear in J. Phys. Soc. Jpn. Vol. 74, No. 6 or
Fluctuating-friction molecular motors
We show that the correlated stochastic fluctuation of the friction
coefficient can give rise to long-range directional motion of a particle
undergoing Brownian random walk in a constant periodic energy potential
landscape. The occurrence of this motion requires the presence of two
additional independent bodies interacting with the particle via friction and
via the energy potential, respectively, which can move relative to each other.
Such three-body system generalizes the classical Brownian ratchet mechanism,
which requires only two interacting bodies. In particular, we describe a simple
two-level model of fluctuating-friction molecular motor that can be solved
analytically. In our previous work [M.K., L.M and D.P. 2000 J. Nonlinear Opt.
Phys. Mater. vol. 9, 157] this model has been first applied to understanding
the fundamental mechanism of the photoinduced reorientation of dye-doped liquid
crystals. Applications of the same idea to other fields such as molecular
biology and nanotechnology can however be envisioned. As an example, in this
paper we work out a model of the actomyosin system based on the
fluctuating-friction mechanism.Comment: to be published in J. Physics Condensed Matter
(http://www.iop.org/Journals/JPhysCM
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