1,117 research outputs found
Rational tangle surgery and Xer recombination on catenanes
The protein recombinase can change the knot type of circular DNA. The action
of a recombinase converting one knot into another knot is normally
mathematically modeled by band surgery. Band surgeries on a 2-bridge knot
N((4mn-1)/(2m)) yielding a (2,2k)-torus link are characterized. We apply this
and other rational tangle surgery results to analyze Xer recombination on DNA
catenanes using the tangle model for protein-bound DNA.Comment: 20 pages, 23 figure
Magnetization curve of the kagome-strip-lattice antiferromagnet
We study the magnetization curve of the Heisenberg model on the
quasi-one-dimensional kagome-strip lattice that shares the same lattice
structure in the inner part with the two-dimensional kagome lattice. Our
numerical calculations based on the density matrix renormalization group method
reveal that the system shows several magnetization plateaus between zero
magnetization and the saturated one; we find the presence of the magnetic
plateaus with the n=7 height of the saturation for n =1,2,3,4,5 and 6 in the S
=1/2 case, whereas we detect only the magnetic plateaus of n =1,3,5 and 6 in
the S =1 case. In the cases of n =2,4 and 6 for the S=1/2 system, the
Oshikawa-Yamanaka-Affleck condition suggests the occurrence of the
translational symmetry breaking (TSB). We numerically confirm this non-trivial
TSB in our results of local magnetizations. We have also found that the
macroscopic jump appears near the saturation field irrespective of the spin
amplitude as well as the two-dimensional kagome model.Comment: 6pages, 3figures, accepted for publication in Journal of Low
Temperature Physic
Characterization of Knots and Links Arising From Site-specific Recombination on Twist Knots
We develop a model characterizing all possible knots and links arising from
recombination starting with a twist knot substrate, extending previous work of
Buck and Flapan. We show that all knot or link products fall into three
well-understood families of knots and links, and prove that given a positive
integer , the number of product knots and links with minimal crossing number
equal to grows proportionally to . In the (common) case of twist knot
substrates whose products have minimal crossing number one more than the
substrate, we prove that the types of products are tightly prescribed. Finally,
we give two simple examples to illustrate how this model can help determine
previously uncharacterized experimental data.Comment: 32 pages, 7 tables, 27 figures, revised: figures re-arranged, and
minor corrections. To appear in Journal of Physics
Ferrimagnetism of the Heisenberg Models on the Quasi-One-Dimensional Kagome Strip Lattices
We study the ground-state properties of the S=1/2 Heisenberg models on the
quasi-onedimensional kagome strip lattices by the exact diagonalization and
density matrix renormalization group methods. The models with two different
strip widths share the same lattice structure in their inner part with the
spatially anisotropic two-dimensional kagome lattice. When there is no magnetic
frustration, the well-known Lieb-Mattis ferrimagnetic state is realized in both
models. When the strength of magnetic frustration is increased, on the other
hand, the Lieb-Mattis-type ferrimagnetism is collapsed. We find that there
exists a non-Lieb-Mattis ferrimagnetic state between the Lieb-Mattis
ferrimagnetic state and the nonmagnetic ground state. The local magnetization
clearly shows an incommensurate modulation with long-distance periodicity in
the non-Lieb-Mattis ferrimagnetic state. The intermediate non-Lieb-Mattis
ferrimagnetic state occurs irrespective of strip width, which suggests that the
intermediate phase of the two-dimensional kagome lattice is also the
non-Lieb-Mattis-type ferrimagnetism.Comment: 9pages, 11figures, accepted for publication in J. Phys. Soc. Jp
Study of Liquefaction Damages of Quay-Walls and Breakwaters During Kobe Earthquake
During Kobe Earthquake, very extensive damages of harbor facilities such as quay-wall and breakwater occurred in Kobe Port and also along the coastal areas between Kobe and Osaka cities. Major causes of the damages were the liquefaction of sands underlying and behind the concrete caisson and also strong earthquake shaking force on the caisson. The degree of damage varied considerably depending on location and also on the size of structure. In order to understand the mechanism of damage as well as the factors that controlled the degree of damage, it was necessary to examine and analyze the case records of damages of these structures. This paper describes the result of such study on liquefaction damage of quay-walls and breakwaters. Through the study, it was found that the movement of sand at shallow depth below the caisson base is mainly responsible for a large settlement of caisson, but the mode of deformation is different between quay wall and breakwater. Also an effective stress liquefaction analysis was performed on the damaged quay-walls and breakwaters in order to check the applicability of effective stress liquefaction analysis on damage assessment. It was found that the effective stress analysis may be used to establish the overall trend of damage variation with the intensity of seismic motion, but problems exist in setting the dynamic parameters for the analysis, such as damping parameters, in order to obtain a reliable result
Frustration-Induced Ferrimagnetism in Heisenberg Spin Chains
We study ground-state properties of the Heisenberg frustrated spin chain with
interactions up to fourth nearest neighbors by the exact-diagonalization method
and the density matrix renormalization group method. We find that
ferrimagnetism is realized not only in the case of S=1/2 but also S=1 despite
that there is only a single spin site in each unit cell determined from the
shape of the Hamiltonian. Our numerical results suggest that a
"multi-sublattice structure" is not required for the occurrence of
ferrimagnetism in quantum spin systems with isotropic interactions.Comment: 6 pages, 3 figures, accepted for publication in Journal of the
Physical Society of Japa
Synchronization of uncoupled oscillators by common gamma impulses: from phase locking to noise-induced synchronization
Nonlinear oscillators can mutually synchronize when they are driven by common
external impulses. Two important scenarios are (i) synchronization resulting
from phase locking of each oscillator to regular periodic impulses and (ii)
noise-induced synchronization caused by Poisson random impulses, but their
difference has not been fully quantified. Here we analyze a pair of uncoupled
oscillators subject to common random impulses with gamma-distributed intervals,
which can be smoothly interpolated between regular periodic and random Poisson
impulses. Their dynamics are charac- terized by phase distributions, frequency
detuning, Lyapunov exponents, and information-theoretic measures, which clearly
reveal the differences between the two synchronization scenarios.Comment: 18 page
Accelerated Kinetics Revealing Metastable Pathways of Magnesiation-Induced Transformations in MnO Polymorphs
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