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Foot protein isoforms are expressed at different times during embryonic chick skeletal muscle development.
We have investigated the time course of expression of the alpha and beta triad junctional foot proteins in embryonic chick pectoral muscle. The level of [3H]ryanodine binding in muscle homogenates is low until day E20 of embryonic development, then increases dramatically at the time of hatching reaching adult levels by day N7 posthatch. The alpha and beta foot protein isoforms increase in abundance concomitantly with [3H]ryanodine binding. Using foot protein isoform-specific antibodies, the alpha foot protein is detected in a majority of fibers in day E10 muscle, while the beta isoform is first observed at low levels in a few fibers in day E15 muscle. A high molecular weight polypeptide, distinct from the alpha and beta proteins, is recognized by antifoot protein antibodies. This polypeptide is observed in day E8 muscle and declines in abundance with continued development. It appears to exist as a monomer and does not bind [3H]ryanodine. In contrast, the alpha isoform present in day E10 muscle and the beta isoform in day E20 muscle are oligomeric and bind [3H]ryanodine suggesting that they may exist as functional calcium channels in differentiating muscle. Comparison of the intracellular distributions of the alpha foot protein, f-actin, the heavy chain of myosin and titin in day E10 muscle indicates that the alpha foot protein is expressed during myofibril assembly and Z line formation. The differential expression of the foot protein isoforms in developing muscle, and their continued expression in mature muscle, is consistent with these proteins making different functional contributions. In addition, the expression of the alpha isoform during the time of organization of a differentiated muscle morphology suggests that foot proteins may participate in events involved in muscle differentiation
31P-NMR and muSR Studies of Filled Skutterudite Compound SmFe4P12: Evidence for Heavy Fermion Behavior with Ferromagnetic Ground State
The 31P-NMR (nuclear magnetic resonance) and muSR (muon spin relaxation)
measurements on the filled skutterudite system SmFe4P12 have been carried out.
The temperature T dependence of the 31P-NMR spectra indicates the existence of
the crystalline electric field effect splitting of the Sm3+$ (J = 5/2)
multiplet into a ground state and an excited state of about 70 K. The
spin-lattice relaxation rate 1/T1 shows the typical behavior of the Kondo
system, i.e., 1/T1 is nearly T independent above 30 K, and varies in proportion
to T (the Korringa behavior, 1/T1 \propto T) between 7.5 K and 30 K. The T
dependence deviated from the Korringa behavior below 7 K, which is independent
of T in the applied magnetic field of 1 kOe, and suppressed strongly in higher
fields. The behavior is explained as 1/T1is determined by ferromagnetic
fluctuations of the uncovered Sm3+ magnetic moments by conduction electrons.
The muSR measurements in zero field show the appearance of a static internal
field associated with the ferromagnetic order below 1.6 K.Comment: 6 pages, 9 figures, to be published in J. Phys. Soc. Jpn. 75 (2006
Could the Ultra Metal-poor Stars be Chemically Peculiar and Not Related to the First Stars?
Chemically peculiar stars define a class of stars that show unusual elemental
abundances due to stellar photospheric effects and not due to natal variations.
In this paper, we compare the elemental abundance patterns of the ultra
metal-poor stars with metallicities [Fe/H] to those of a subclass of
chemically peculiar stars. These include post-AGB stars, RV Tauri variable
stars, and the Lambda Bootis stars, which range in mass, age, binarity, and
evolutionary status, yet can have iron abundance determinations as low as
[Fe/H] . These chemical peculiarities are interpreted as due to the
separation of gas and dust beyond the stellar surface, followed by the
accretion of dust depleted-gas. Contrary to this, the elemental abundances in
the ultra metal-poor stars are thought to represent yields of the most
metal-poor supernova and, therefore, observationally constrain the earliest
stages of chemical evolution in the Universe. The abundance of the elements in
the photospheres of the ultra metal-poor stars appear to be related to the
condensation temperature of that element; if so, then their CNO abundances
suggest true metallicities of [X/H]~ -2 to -4, rather than their present
metallicities of [Fe/H] < -5.Comment: Accepted for ApJ. 17 pages, 10 figure
Quasi-Topological Insulator and Trigonal Warping in Gated Bilayer Silicene
Bilayer silicene has richer physical properties than bilayer graphene due to
its buckled structure together with its trigonal symmetric structure. The
buckled structure arises from a large ionic radius of silicon, and the trigonal
symmetry from a particular way of hopping between two silicenes. It is a
topologically trivial insulator since it carries a trivial
topological charge. Nevertheless, its physical properties are more akin to
those of a topological insulator than those of a band insulator. Indeed, a
bilayer silicene nanoribbon has edge modes which are almost gapless and
helical. We may call it a quasi-topological insulator. An important observation
is that the band structure is controllable by applying the electric field to a
bilayer silicene sheet. We investigate the energy spectrum of bilayer silicene
under electric field. Just as monolayer silicene undergoes a phase transition
from a topological insulator to a band insulator at a certain electric field,
bilayer silicene makes a transition from a quasi-topological insulator to a
band insulator beyond a certain critical field. Bilayer silicene is a metal
while monolayer silicene is a semimetal at the critical field. Furthermore we
find that there are several critical electric fields where the gap closes due
to the trigonal warping effect in bilayer silicene.Comment: 8 pages, 11 figures, to be published in J. Phys. Soc. Jp
The survival and destruction of X-ray coronae of early-type galaxies in the rich cluster environments: a case study of Abell 1367
A new Chandra observation of the northwest region of the galaxy cluster A1367
reveals four cool galaxy coronae (0.4 - 1.0 keV) embedded in the hot
intracluster medium (ICM) (5 - 6 keV). While the large coronae of NGC 3842 and
NGC 3837 appear symmetric and relaxed, the galaxy coronae of the \lsim L*
galaxies (NGC 3841 and CGCG 97090) are disturbed and being stripped. Massive
galaxies, with dense cooling cores, are better able to resist ram pressure
stripping and survive in rich environments than \lsim L* galaxies whose
galactic coronae are much less dense. The survival of these cool coronae
implies that thermal conduction from the hot surrounding ICM has to be
suppressed by a factor of at least 60, at the corona boundary. Within the
galaxy coronae of NGC 3842 and NGC 3837, stellar mass loss or heat conduction
with the Spitzer value may be sufficient to balance radiative cooling. Energy
deposition at the ends of collimated jets may heat the outer coronae, but allow
the survival of a small, dense gas core (e.g., NGC 3842 in A1367 and NGC 4874
in Coma). The survived X-ray coronae become significantly smaller and fainter
with the increasing ambient pressure.Comment: 11 pages, 7 figures, emulateapj5, accepted by Ap
Hypernetwork functional image representation
Motivated by the human way of memorizing images we introduce their functional
representation, where an image is represented by a neural network. For this
purpose, we construct a hypernetwork which takes an image and returns weights
to the target network, which maps point from the plane (representing positions
of the pixel) into its corresponding color in the image. Since the obtained
representation is continuous, one can easily inspect the image at various
resolutions and perform on it arbitrary continuous operations. Moreover, by
inspecting interpolations we show that such representation has some properties
characteristic to generative models. To evaluate the proposed mechanism
experimentally, we apply it to image super-resolution problem. Despite using a
single model for various scaling factors, we obtained results comparable to
existing super-resolution methods
The intrinsic strangeness and charm of the nucleon using improved staggered fermions
We calculate the intrinsic strangeness of the nucleon, - ,
using the MILC library of improved staggered gauge configurations using the
Asqtad and HISQ actions. Additionally, we present a preliminary calculation of
the intrinsic charm of the nucleon using the HISQ action with dynamical charm.
The calculation is done with a method which incorporates features of both
commonly-used methods, the direct evaluation of the three-point function and
the application of the Feynman- Hellman theorem. We present an improvement on
this method that further reduces the statistical error, and check the result
from this hybrid method against the other two methods and find that they are
consistent. The values for and found here, together with
perturbative results for heavy quarks, show that dark matter scattering through
Higgs-like exchange receives roughly equal contributions from all heavy quark
flavors.Comment: 17 pages, 14 figure
Probing Ion-Ion and Electron-Ion Correlations in Liquid Metals within the Quantum Hypernetted Chain Approximation
We use the Quantum Hypernetted Chain Approximation (QHNC) to calculate the
ion-ion and electron-ion correlations for liquid metallic Li, Be, Na, Mg, Al,
K, Ca, and Ga. We discuss trends in electron-ion structure factors and radial
distribution functions, and also calculate the free-atom and metallic-atom
form-factors, focusing on how bonding effects affect the interpretation of
X-ray scattering experiments, especially experimental measurements of the
ion-ion structure factor in the liquid metallic phase.Comment: RevTeX, 19 pages, 7 figure
Heavy fermion fluid in high magnetic fields: an infrared study of CeRuSb
We report a comprehensive infrared magneto-spectroscopy study of
CeRuSb compound revealing quasiparticles with heavy effective mass
m, with a detailed analysis of optical constants in fields up to 17 T. We
find that the applied magnetic field strongly affects the low energy
excitations in the system. In particular, the magnitude of m 70
m (m is the quasiparticle band mass) at 10 K is suppressed by as much
as 25 % at 17 T. This effect is in quantitative agreement with the mean-field
solution of the periodic Anderson model augmented with a Zeeman term
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