1,426 research outputs found
Nonlinearly Realized Extended Supergravity
We provide nonlinear realization of supergravity with an arbitrary number of
supersymmetries by means of coset construction. The number of gravitino degrees
of freedom counts the number of supersymmetries, which will be possibly probed
in future experiments. We also consider goldstino embedding in the construction
to discuss the relation to nonlinear realization with rigid supersymmetries.Comment: 19 page
Topological chiral magnonic edge mode in a magnonic crystal
Topological phases have been explored in various fields in physics such as
spintronics, photonics, liquid helium, correlated electron system and
cold-atomic system. This leads to the recent foundation of emerging materials
such as topological band insulators, topological photonic crystals and
topological superconductors/superfluid. In this paper, we propose a topological
magnonic crystal which provides protected chiral edge modes for magnetostatic
spin waves. Based on a linearized Landau-Lifshitz equation, we show that a
magnonic crystal with the dipolar interaction acquires spin-wave volume-mode
band with non-zero Chern integer. We argue that such magnonic systems are
accompanied by the same integer numbers of chiral spin-wave edge modes within a
band gap for the volume-mode bands. In these edge modes, the spin wave
propagates in a unidirectional manner without being scattered backward, which
implements novel fault-tolerant spintronic devices.Comment: 12 pages, 7 figure
Chandra Observations of A Galactic Supernova Remnant Vela Jr.: A New Sample of Thin Filaments Emitting Synchrotron X-Rays
A galactic supernova remnant (SNR) Vela Jr. (RX J0852.04622, G266.61.2)
shows sharp filamentary structure on the north-western edge of the remnant in
the hard X-ray band. The filaments are so smooth and located on the most outer
side of the remnant. We measured the averaged scale width of the filaments
( and ) with excellent spatial resolution of {\it Chandra}, which are
in the order of the size of the point spread function of {\it Chandra} on the
upstream side and 49.5 (36.0--88.8) arcsec on the downstream side,
respectively. The spectra of the filaments are very hard and have no line-like
structure, and were well reproduced with an absorbed power-law model with
2.67 (2.55--2.77), or a {\tt SRCUT} model with = 4.3
(3.4--5.3) Hz under the assumption of . These results
imply that the hard X-rays are synchrotron radiation emitted by accelerated
electrons, as mentioned previously. Using a correlation between a function
and the SNR age, we estimated the
distance and the age of Vela Jr.: the estimated distance and age are 0.33
(0.26--0.50) kpc and 660 (420--1400) years, respectively. These results are
consistent with previous reports, implying that --age relation may be
a useful tool to estimate the distance and the age of synchrotron X-ray
emitting SNRs.Comment: 19 pages, 8 figures, ApJ, in pres
Spontaneous Extraskeletal Osteosarcoma in the Stomach of an Aged F344 Rat
Extraskeletal osteosarcoma is a very rare tumor in humans and animals including
rats. This paper describes a case of extraskeletal osteosarcoma observed in the
glandular stomach of an aged female Fischer 344 rat. Grossly, a whitish solid
mass was observed at the greater curvature of the glandular stomach.
Histologically, the tumor consisted of both atypical polygonal and pleomorphic
spindle-shaped cells, with pleomorphic nuclei, and it contained variable amounts
of osteoids and small clumps of mature bone tissue. In addition, mitotic figures
were frequently observed. Neither invasion of the muscle layer or vessels in the
stomach nor metastasis to distant organs was detected. There were no skeletal
tumors in the body. Immunohistochemically, the tumor cells were positive for
osteocalcin, osteonectin, vimentin and S-100 protein. Judging from these
results, the present tumor was diagnosed as extraskeletal osteosarcoma. This is
the first report of spontaneous extraskeletal osteosarcoma arising from the
stomach in a rat
Constraining the time variation of the coupling constants from cosmic microwave background: effect of \Lambda_{QCD}
We investigate constraints on the time variation of the fine structure
constant between the recombination epoch and the present epoch,
\Delta\alpha/\alpha \equiv (\alpha_{rec} - \alpha_{now})/\alpha_{now}, from
cosmic microwave background (CMB) taking into account simultaneous variation of
other physical constants, namely the electron mass m_{e} and the proton mass
m_{p}. In other words, we consider the variation of Yukawa coupling and the QCD
scale \Lambda_{QCD} in addition to the electromagnetic coupling. We clarify
which parameters can be determined from CMB temperature anisotropy in terms of
singular value decomposition. Assuming a relation among variations of coupling
constants governed by a single scalar field (the dilaton), the 95% confidence
level (C.L.) constraint on \Delta\alpha/\alpha is found to be -8.28 \times
10^{-3} < \Delta\alpha/\alpha < 1.81 \times 10^{-3}, which is tighter than the
one obtained by considering only the change of \alpha and m_{e}. We also obtain
the constraint on the time variation of the proton-to-electron mass ratio \mu
\equiv m_{p}/m_{e} to be -0.52 < \Delta\mu/\mu < 0.17 (95% C.L.) under the same
assumption. Finally, we also implement a forecast for constraints from the
PLANCK survey.Comment: 25 pages, 4 figures; references adde
Spin and orbital ordering in double-layered manganites
We study theoretically the phase diagram of the double-layered perovskite
manganites taking into account the orbital degeneracy, the strong Coulombic
repulsion, and the coupling with the lattice deformation. Observed spin
structural changes as the increased doping are explained in terms of the
orbital ordering and the bond-length dependence of the hopping integral along
-axis. Temperature dependence of the neutron diffraction peak corresponding
to the canting structure is also explained. Comparison with the 3D cubic system
is made.Comment: 7 figure
Mass Spectra-Based Framework for Automated Structural Elucidation of Metabolome Data to Explore Phytochemical Diversity
A novel framework for automated elucidation of metabolite structures in liquid chromatography–mass spectrometer metabolome data was constructed by integrating databases. High-resolution tandem mass spectra data automatically acquired from each metabolite signal were used for database searches. Three distinct databases, KNApSAcK, ReSpect, and the PRIMe standard compound database, were employed for the structural elucidation. The outputs were retrieved using the CAS metabolite identifier for identification and putative annotation. A simple metabolite ontology system was also introduced to attain putative characterization of the metabolite signals. The automated method was applied for the metabolome data sets obtained from the rosette leaves of 20 Arabidopsis accessions. Phenotypic variations in novel Arabidopsis metabolites among these accessions could be investigated using this method
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