420 research outputs found
The Ejecta Distributions of the Heavy Elements in the Cygnus Loop
We analyzed the metal distribution of the Cygnus Loop using 14 and 7
pointings observation data obtained by the \textit{Suzaku} and the
\textit{XMM-Newton} observatories. The spectral analysis shows that all the
spectra are well fitted by the two- non-equilibrium ionization plasma
model as shown by the earlier observations. From the best-fit parameters of the
high- component, we calculated the emission measures about various
elements and showed the metal distribution of the ejecta component. We found
that the distributions of Si and Fe are centered at the southwest of the
geometric center toward the blow-out region. From the best-fit parameters, we
also estimated the progenitor mass of the Cygnus Loop from our field of view
and the metal rich region with a radius of 25 arcmin from the metal center. The
result from the metal circle is similar to that from our entire FOV, which
suggests the mixing of the metal. From the results, we estimated the mass of
the progenitor star at 12-15\MO.Comment: 15 pages, 5 figures, PASJ, Vol.61, No.
Optical signature of Weyl electronic structures in tantalum pnictides Ta ( P, As)
To investigate the electronic structure of Weyl semimetals Ta (P,
As), optical conductivity [] spectra are measured over a wide
range of photon energies and temperatures, and these measured values are
compared with band calculations. Two significant structures can be observed: a
bending structure at 85 meV in TaAs, and peaks at
50 meV (TaP) and 30 meV (TaAs). The bending structure
can be explained by the interband transition between saddle points connecting a
set of Weyl points. The temperature dependence of the peak intensity can
be fitted by assuming the interband transition between saddle points connecting
a set of Weyl points. Owing to the different temperature dependence of
the Drude weight in both materials, it is found that the Weyl points of TaAs
are located near the Fermi level, whereas those of TaP are further away.Comment: 8 pages, 6 figure
Possible Charge-Exchange X-Ray Emission in the Cygnus Loop Detected with Suzaku
X-ray spectroscopic measurements of the Cygnus Loop supernova remnant
indicate that metal abundances throughout most of the remnant's rim are
depleted to about 0.2 times the solar value. However, recent X-ray studies have
revealed in some narrow regions along the outermost rim anomalously "enhanced"
abundances (up to about 1 solar). The reason for these anomalous abundances is
not understood. Here, we examine X-ray spectra in annular sectors covering
nearly the entire rim of the Cygnus Loop using Suzaku (21 pointings) and
XMM-Newton (1 pointing). We find that spectra in the "enhanced" abundance
regions commonly show a strong emission feature at about 0.7 keV. This feature
is likely a complex of He-like O K(gamma + delta + epsilon), although other
possibilities cannot be fully excluded. The intensity of this emission relative
to He-like O Kalpha appears to be too high to be explained as thermal emission.
This fact, as well as the spatial concentration of the anomalous abundances in
the outermost rim, leads us to propose an origin from charge-exchange processes
between neutrals and H-like O. We show that the presence of charge-exchange
emission could lead to the inference of apparently "enhanced" metal abundances
using pure thermal emission models. Accounting for charge-exchange emission,
the actual abundances could be uniformly low throughout the rim. The overall
abundance depletion remains an open question.Comment: Published in Ap
The Abundance Inhomogeneity in the Northern Rim of the Cygnus Loop
We observed the northern rim of the Cygnus Loop with the \textit{Suzaku}
observatory in 5 pointings (P21-P25). From the spatially resolved analysis, all
the spectra are well fitted by the single component of the non-equilibrium
ionization plasma model. From the best-fit parameters, we found that the
abundances of the heavy elements are significantly lower than the solar values
except those at the outermost edge in P21 and P22. The origin of the depleted
metal abundances is still unclear while such deficiencies have been reported
from many other rim observations of the Loop. To explain these depletion at the
rim regions, we considered the several possibilities. The effects of the
resonance-line-scattering and the grain condensation lower the values of the
abundances. However, these are not sufficient to account for the abundance
depletion observed.
We found that the abundances at the outermost edge in P21 and P22 are higher
than those at the other regions. From the morphological point of view, it is
reasonable to consider that this abundance inhomogeneity is derived from the
breakout or the thinness of the cavity wall of the Loop.Comment: 15 pages, 7 figures, PASJ, Vol.61, No.
Functional Differentiation of Memory Retrieval Network in Macaque Posterior Parietal Cortex
SummaryHuman fMRI studies revealed involvement of the posterior parietal cortex (PPC) during memory retrieval. However, corresponding memory-related regions in macaque PPC have not been established. In this monkey fMRI study, comparisons of cortical activity during correct recognition of previously seen items and rejection of unseen items revealed two major PPC activation sites that were differentially characterized by a serial probe recognition paradigm: area PG/PGOp in inferior parietal lobule, along with the hippocampus, was more active for initial item retrieval, while area PEa/DIP in intraparietal sulcus was for the last item. Effective connectivity analyses revealed that connectivity from hippocampus to PG/PGOp, but not to PEa/DIP, increased during initial item retrieval. The two parietal areas with differential serial probe recognition profiles were embedded in two different subnetworks of the brain-wide retrieval-related regions. These functional dissociations in the macaque PPC imply the functional correspondence of retrieval-related PPC networks in macaques and humans
Clinical usefulness of super high-resolution liquid crystal displays using independent sub-pixel driving technology
金沢大学医薬保健研究域保健学系We have developed and reported super-high resolution liquid crystal displays (SHR-LCDs) using a new resolution enhancement technology of the independent sub-pixel driving (ISD) that utilizes three sub-pixels contained in each pixel element. This technology realizes the three-times resolution enhancement of monochrome LCDs. A 15 mega-pixel (MP) SHR-LCD out of a 5MP LCD and a 9MP SHR-LCD out of a 3MP LCD, for example, are realized by this technology, which improves the depiction ability of detailed image shapes such as micro-calcifications of a mammography. Furthermore, the ISD technology brings not only resolution enhancement but also noise reduction effect by the high-frequency data sampling in displaying the clinical images. In this study, we have investigated the clinical efficacy of the SHR-LCDs by means of phantom observation studies and blind observer comparison studies using clinical mammography images performed by radiologists. We used a conventional 5MP LCD for a comparison of a 15MP SHR-LCD and a 9MP SHR-LCD to evaluate their efficacy. From the results of the studies, it was indicated that the SHR-LCDs using the ISD technology had the excellent ability to display the high-resolution digital mammography images. © 2008 Springer-Verlag Berlin Heidelberg
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