5,424 research outputs found
Anomalies in the Coloration of Japanese Amphibians and Their Applications in Genetic Research
Color mutations and variations in amphibians are often found in the wild. They are potential subjects for genetic research, and are also a good indicator of environmental changes, because they normally occur during two distinct stages of the amphibian life cycle: in water, during the tadpole stage, and on land, after metamorphosis. However, reviews and compilations on the mutations and variations in wild-caught amphibians are scarce. Here, I present the color mutations and variations in Japanese frog species and show the results of our genetic analyses on the mechanisms of color expression and their implications
The MHD Kelvin-Helmholtz Instability III: The Role of Sheared Magnetic Field in Planar Flows
We have carried out simulations of the nonlinear evolution of the
magnetohydrodynamic (MHD) Kelvin-Helmholtz (KH) instability for compressible
fluids in -dimensions, extending our previous work by Frank et al
(1996) and Jones \etal (1997). In the present work we have simulated flows in
the x-y plane in which a ``sheared'' magnetic field of uniform strength
``smoothly'' rotates across a thin velocity shear layer from the z direction to
the x direction, aligned with the flow field. We focus on dynamical evolution
of fluid features, kinetic energy dissipation, and mixing of the fluid between
the two layers, considering their dependence on magnetic field strength for
this geometry. The introduction of magnetic shear can allow a Cat's Eye-like
vortex to form, even when the field is stronger than the nominal linear
instability limit given above. For strong fields that vortex is asymmetric with
respect to the preliminary shear layer, however, so the subsequent dissipation
is enhanced over the uniform field cases of comparable field strength. In fact,
so long as the magnetic field achieves some level of dynamical importance
during an eddy turnover time, the asymmetries introduced through the magnetic
shear will increase flow complexity, and, with that, dissipation and mixing.
The degree of the fluid mixing between the two layers is strongly influenced by
the magnetic field strength. Mixing of the fluid is most effective when the
vortex is disrupted by magnetic tension during transient reconnection, through
local chaotic behavior that follows.Comment: 14 pages including 9 figures (4 figures in degraded jpg format), full
paper with original quality figures available via anonymous ftp at
ftp://canopus.chungnam.ac.kr/ryu/mhdkh2d.uu, to appear in The Astrophysical
Journa
Electronic structure and effects of dynamical electron correlation in ferromagnetic bcc-Fe, fcc-Ni and antiferromagnetic NiO
LDA+DMFT method in the framework of the iterative perturbation theory (IPT)
with full LDA Hamiltonian without mapping onto the effective Wannier orbitals.
We then apply this LDA+DMFT method to ferromagnetic bcc-Fe and fcc-Ni as a test
of transition metal, and to antiferromagnetic NiO as an example of transition
metal oxide. In Fe and Ni, the width of occupied 3d bands is narrower than
those in LDA and Ni 6eV satellite appears. In NiO, the resultant electronic
structure is of charge-transfer insulator type and the band gap is 4.3eV. These
results are in good agreement with the experimental XPS. The configuration
mixing and dynamical correlation effects play a crucial role in these results
Capture of free-flying payloads with flexible space manipulators
A recently developed control system for capturing free-flying payloads with flexible manipulators is discussed. Three essential points in this control system are, calculating optimal path, using a vision sensor for an external sensor, and controlling active vibration. Experimental results are shown using a planar flexible manipulator
Conductance of a single molecule anchored by an isocyanide substituent to gold electrodes
The effect of anchoring group on the electrical conductance of a single
molecule bridging two Au electrodes was studied using di-substituted
(isocyanide (CN-), thiol (S-) or cyanide (NC-)) benzene. The conductance of a
single Au/1,4-diisocyanobenzene/Au junction anchored by isocyanide via a C atom
(junction with the Au-CN bond) was (). The
value was comparable to of a single
Au/1,4-benzenedithiol/Au junction with the Au-S bond. The
Au/1,4-dicyanobenzene/Au molecular junction with the Au-NC bond did not show
well-defined conductance values. The metal-molecule bond strength was estimated
by the distance over which the molecular junction was stretched before
breakdown. The stretched length of the molecular junction with the Au-CN bond
was comparable to that of the Au junction, indicating that the Au-CN bond was
stronger than the Au-Au bond.Comment: 3 figures, to be appear in Appl. Phys. Let
Nonlinear wave propagation through cold plasma
Electromagnetic wave propagation through cold collision free plasma is
studied using the nonlinear perturbation method. It is found that the equations
can be reduced to the modified Kortweg-de Vries equation
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A note on the alpha-quantile option
In this communication, we discuss some properties of a class of path dependent options based on the α-quantiles of Brownian motion. In particular we show that such options are well behaved in relation to standard options and comparatively cheaper than an equivalent class of lookback options
Orbital selectivity of the kink in the dispersion of Sr2RuO4
We present detailed energy dispersions near the Fermi level on the monolayer
perovskite ruthenate Sr2RuO4, determined by high-resolution angle-resolved
photoemission spectroscopy. An orbital selectivity of the kink in the
dispersion of Sr2RuO4 has been found: A kink for the Ru 4d_xy orbital is
clearly observed, but not for the Ru 4d_yz and 4d_zx ones. The result provides
insight into the origin of the kink.Comment: 5 pages, 4 figures. Accepted for publication in Phys. Rev.
Pulse-coupled resonate-and-fire models
We analyze two pulse-coupled resonate-and-fire neurons. Numerical simulation
reveals that an anti-phase state is an attractor of this model. We can
analytically explain the stability of anti-phase states by means of a return
map of firing times, which we propose in this paper. The resultant stability
condition turns out to be quite simple. The phase diagram based on our theory
shows that there are two types of anti-phase states. One of these cannot be
seen in coupled integrate-and-fire models and is peculiar to resonate-and-fire
models. The results of our theory coincide with those of numerical simulations.Comment: 15 pages, 8 figure
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