639 research outputs found
On the origin of the hump structure in the in-plane optical conductivity of high Tc cuprates based on a SU(2) slave-boson theory
An improved version of SU(2) slave-boson approach is applied to study the
in-plane optical conductivity of the two dimensional systems of high Tc
cuprates. We investigate the role of fluctuations of both the phase and
amplitude of order parameters on the (Drude) peak-dip-hump structure in the
in-plane conductivity as a function of hole doping concentration and
temperature. The mid-infrared(MIR) hump in the in-plane optical conductivity is
shown to originate from the antiferromagnetic spin fluctuations of short
range(the amplitude fluctuations of spin singlet pairing order parameters),
which is consistent with our previous U(1) study. However the inclusion of both
the phase and amplitude fluctuations is shown to substantially improve the
qualitative feature of the optical conductivity by showing substantially
reduced Drude peak widths for entire doping range. Both the shift of the hump
position to lower frequency and the growth of the hump peak height with
increasing hole concentration is shown to be consistent with observations.Comment: 7 pages, 6 figure
Supernova Axion Emissivity with Resonance in Heavy Baryon Chiral Perturbation Theory
In this paper, we evaluate the energy loss rate of supernovae induced by the
axion emission process with the resonance
in the heavy baryon chiral perturbation theory for the first time. Given the
axion-nucleon- interactions, we include the previously ignored
-mediated graphs to the process. In particular,
the -mediated diagram can give a resonance contribution to the
supernova axion emission rate when the center-of-mass energy of the pion and
proton approaches the mass. With these new contributions, we
find that for the typical supernova temperatures, compared with the earlier
work with the axion-nucleon (and axion-pion-nucleon contact) interactions, the
supernova axion emissivity can be enhanced by a factor of 4(2) in the
Kim-Shifman-Vainshtein-Zakharov model and up to a factor of 5(2) in the
Dine-Fischler-Srednicki-Zhitnitsky model with small values.
Remarkably, we notice that the resonance gives a destructive
contribution to the supernova axion emission rate at high supernova
temperatures, which is a nontrivial result in this study.Comment: 17 pages, 4 figures, typo is fixed, references updated. Matches
version published in Physical Review
The Interaction of Phospholipase C-{beta}3 with Shank2 Regulates mGluR-mediated Calcium Signal
Phospholipase C-{beta} isozymes that are activated by G protein-coupled receptors (GPCR) and heterotrimeric G proteins carry a PSD-95/Dlg/ZO-1 (PDZ) domain binding motif at their C terminus. Through interactions with PDZ domains, this motif may endow the PLC-{beta} isozyme with specific roles in GPCR signaling events that occur in compartmentalized regions of the plasma membrane. In this study, we identified the interaction of PLC-{beta}3 with Shank2, a PDZ domain-containing multimodular scaffold in the postsynaptic density (PSD). The C terminus of PLC-{beta}3, but not other PLC-{beta} isotypes, specifically interacts with the PDZ domain of Shank2. Homer 1b, a Shank-interacting protein that is linked to group I metabotropic glutamate receptors and IP3 receptors, forms a multiple complex with Shank2 and PLC-{beta}3. Importantly, microinjection of a synthetic peptide specifically mimicking the C terminus of PLC-{beta}3 markedly reduces the mGluR-mediated intracellular calcium response. These results demonstrate that Shank2 brings PLC-{beta}3 closer to Homer 1b and constitutes an efficient mGluR-coupled signaling pathway in the PSD region of neuronal synapses
Precursor Phenomena of Barium Titanate Single Crystals Grown Using a Solid-State Single Crystal Growth Method Studied with Inelastic Brillouin Light Scattering and Birefringence Measurements
The nature of precursor phenomena in the paraelectric phase of ferroelectrics is one of the
main questions to be resolved from a fundamental point of view. Barium titanate (BaTiO3) is one
of the most representative perovskite-structured ferroelectrics intensively studied until now. The
pretransitional behavior of BaTiO3 single crystal grown using a solid-state crystal growth (SSCG)
method was investigated for the first time and compared to previous results. There is no melting
process in the SSCG method, thus the crystal grown using a SSCG method have inherent higher
levels of impurity and defect concentrations, which is a good candidate for investigating the effect of
crystal quality on the precursor phenomena. The acoustic, dielectric, and piezoelectric properties,
as well as birefringence, of the SSCG-grown BaTiO3 were examined over a wide temperature range.
Especially, the acoustic phonon behavior was investigated in terms of Brillouin spectroscopy, which
is a complementary technique to Raman spectroscopy. The obtained precursor anomalies of the
SSCG-grown BaTiO3 in the cubic phase were similar to those of other single crystals, in particular,
of high-quality single crystal grown by top-seeded solution growth method. These results clearly
indicate that the observed precursor phenomena are common and intrinsic effect irrespective of the
crystal quality
Comparison of The Genome Profiles Between Head and Body Lice
The body louse (Pediculus humanus humanus) is known to have diverged from the head louse (P. humanus capitis) but genomic differences between these two subspecies still remain unexplored. To compare genomic profiles between head and body lice, whole genome sequences of head lice were determined by next generation sequencing methods based on both Illumina Genome analyzer and Roche GS FLX pyrosequencing and compared with the reference genome sequences of the body louse. Total consensuses generated by mapping to the body louse genome in conjunction with de novo assembly of head louse genome sequences revealed a head louse genome size of 110 Mbp with a 96% coverage of the body louse genome sequences. A total of 12,651 genes were predicted from the head louse genome sequences although more precise assembly and functional annotation of the genome is required for a more accurate gene count. Among the 873 genes that were putatively specific to the head louse, 15 genes were confirmed to be transcribed in both head and body lice, suggesting the previously estimated gene number of the body louse was likely underestimated. The single nucleotide polymorphism analysis showed that the nucleotide diversity of genome between head and body lice was 2.2%, which was larger than that of the transcriptome between head and body lice. An endosymbiont genome analysis showed that the composition of endosymbionts in head lice was similar to that of body lice and Candidatus Riesia pediculicola was the primary endosymbiont in both head and body lice
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