1,315 research outputs found
Spin wave dispersion based on the quasiparticle self-consistent method: NiO, MnO and -MnAs
We present spin wave dispersions in MnO, NiO, and -MnAs based on the
quasiparticle self-consistent method (\qsgw), which determines an optimum
quasiparticle picture. For MnO and NiO, \qsgw results are in rather good
agreement with experiments, in contrast to the LDA and LDA+U description. For
-MnAs, we find a collinear ferromagnetic ground state in \qsgw, while
this phase is unstable in the LDA.Comment: V2: add another figure for SW life time. Formalism is detaile
Half-skyrmion picture of single hole doped CuO_2 plane
Based on the Zhang-Rice singlet picture, it is argued that the half-skyrmion
is created by the doped hole in the single hole doped high-T_c cuprates with
N'eel ordering. The spin configuration around the Zhang-Rice singlet, which has
the form of superposition of the two different d-orbital hole spin states, is
studied within the non-linear \sigma model and the CP^1 model. The spin
configurations associated with each hole spin state are obtained, and we find
that the superposition of these spin configuration turns out to be the
half-skyrmion that is characterized by a half of the topological charge. The
excitation spectrum of the half-skyrmion is obtained by making use of Lorentz
invariance of the effective theory and is qualitatively in good agreement with
angle resolved photoemission spectroscopy on the parent compunds. Estimated
values of the parameters contained in the excitation spectrum are in good
agreement with experimentally obtained values. The half-skyrmion theory
suggests a picture for the difference between the hole doped compounds and the
electron doped compounds.Comment: 13 pages, 2 figures, to be published in Phys. Rev.
Tunneling effect on composite fermion pairing state in bilayer quantum Hall system
We discuss the composite fermion pairing state in bilayer quantum Hall
systems. After the evaluation of the range of the inter-layer separation in
which the quantum Hall state is stabilized, we discuss the effect of
inter-layer tunneling on the composite fermion pairing state at \nu=1/2. We
show that there is a cusp at the transition point between the Halperin (3,3,1)
state and the Pfaffian state.Comment: 6 pages, 4 figures, accepted for publication in Phys. Rev.
Re-examination of half-metallic ferromagnetism for doped LaMnO3 in quasiparticle self-consistent method
We apply the quasiparicle self-consistent (\qsgw) method to a cubic
virtual-crystal alloy LaBaMnO %(LBMO) as a theoretical
representative for colossal magnetoresistive perovskite manganites. The \qsgw\
predicts it as a fully-polarized half-metallic ferromagnet for a wide range of
and lattice constant. Calculated density of states and dielectric functions
are consistent with experiments. In contrast, the energies of calculated spin
wave are very low in comparison with experiments. This is affected neither by
rhombohedral deformation nor the intrinsic deficiency in the \qsgw method. Thus
we ends up with a conjecture that phonons related to the Jahn-Teller distortion
should hybridize with spin waves more strongly than people thought until now
Structural Survey and Artificial Induction of Aloeswood
この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました
Studies of transverse and longitudinal relaxations of Mn in molecular cluster magnet MnAc
The transverse and longitudinal relaxation rates 1/ and 1/ of
Mn in molecular cluster magnet MnAc have been measured al low
temperatures down to 200mK and in the fields upto 9T. Both of 1/ and
1/ exhibit remarkable decreases with decreasing temperature and with
increasing field, with the relative relation . In the
analysis, we adopt a simple model that the thermal fluctuation of the cluster
spin =10 associated with the spin-phonon interactionis, is only due to the
excitation to the first excited state from the ground state with the average
life-times and (). We show that
1/ is interpreted in terms of the strong collision regime as given by
1/, and that 1/ is understood by the high-frequency limit based
on standard perturbation treatment for the step-wise fluctuating field, thus
being proportional to 1/.Comment: 12 pages, 11 fugures, revtex
Highly multiplexed immune profiling throughout adulthood reveals kinetics of lymphocyte infiltration in the aging mouse prostate
Aging is a significant risk factor for cancer in several tissues, including the prostate. Defining the kinetics of age-related changes in these tissues is critical for identifying regulators of aging and evaluating interventions to slow the aging process and reduce disease risk. An altered microenvironment is characteristic of prostatic aging in mice. Whether features of aging in the prostate emerge predominantly in old age or earlier in adulthood has not previously been established. Using comprehensive immune profiling and time-course analysis, we show that populations of T and B lymphocytes increase in the mouse prostate between 6 and 12 months of age. When comparing the prostate to other urogenital tissues, we found similar features of age-related inflammation in the mouse bladder. In summary, our study offers new insight into the kinetics of prostatic inflammaging and the window when interventions to slow down age-related changes may be most effective
Molecular characterization of cytochrome P450 1B1 and effect of benzo(a) pyrene on its expression in Nile tilapia (Oreochromis niloticus)
Cytochrome P4501 (CYP1) family enzymes are most active in hydroxylating a variety of environmental contaminants including Polyaromatic Hydrocarbons (PAH), planar polychlorinated biphenyls and arylamines. CYP1B which belongs to the cytochrome P450 superfamily of genes, is involved in the oxidation of endogenous and exogenous compounds, and could potentially be a useful biomarker in fish for exposure to arylhydrocarbon receptors (AhR) ligands. In this study, a new complementary DNA (cDNA) of the CYP1B subfamily encoding 1B1 was isolated from Nile tilapia (Oreochromis niloticus) liver after intracoelomic injection with benzo (a) pyrene (BaP). The full-length cDNA was 2107 base pair (bp) long and contained a 5' noncoding region of 29 bp, an open reading frame of 1527 bp coding for 508 amino acids and a stop codon, and a 3' noncoding region of 551 bp, respectively. The deduced amino acid sequence of Nile tilapia CYP1B1 shows similarities of 79.7, 70.3, 65.7, 65.4, 65.0, and 63.7% with Plaice CYP1B1, Japanese eel CYP1B1, zebra fish CYP1B1, common carp CYP1B1, common carp CYP1B2 and Channel catfish CYP1B1, respectively. The phylogenetic tree based on the amino acid sequences clearly shows tilapia CYP1B1 and Plaice CYP1B1 to be more closely related to each other than to the other CYP1B subfamilies. Furthermore, real-time PCR was used for measuring BaP induction of CYP1B1 mRNA in different organs of tilapia (O. niloticus), using β-actin gene as internal control, and the results revealed that there was a large increase in CYP1B1 mRNA in liver (22.8), intestine (2.0) and muscles (1.3).Keywords: Oreochromis niloticus, benzo (a) pyrene, CYP1B1 cDNA, sequence analysis, real-time PCR
Setting a precautionary catch limit for Antarctic krill
A revised precautionary catch limit for Antarctic krill (Euphausia superba) in the Scotia Sea of 4 million tons was recently adopted by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). The limit was based on a total biomass of 44.3 million tons, as estimated from an acoustic and net survey of krill across the Scotia Sea sector of the Southern Ocean, and a harvest rate of 9.1%, as determined from an analysis of the risks of exceeding defined conservation criteria. We caution, however, that before the fishery can expand to the 4-inillion-ton level it will be necessary to establish mechanisms to avoid concentration of fishing effort, particularly in proximity to colonies of land-breeding krill predators, and to consider the effects of krill immigrating into the region from multiple sources
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