592 research outputs found
A Super Bubble Candidate in the Galactic Center and a Local Enhancement G359.77-0.09
A 20' \times 16' elliptical ring-like structure has been found near the
Galactic center in the narrow energy band corresponding to the K line
from He-like sulfur. In the ring, two diffuse sources are found, a supernova
remnant candidate G359.79-0.26 and an unidentified source G359.77-0.09. The
X-ray spectrum of G359.77-0.09 is similar to that of G359.79-0.26, which can be
explained by an absorbed thin thermal plasma model with temperatures of 0.7 and
1.0 keV. The absorption column densities of these two sources are large (N_H =
6.9 \times 10^{22} and 4.5 \times 10^{22} cm^{-2}) and are consistent with that
of the Galactic center distance. The X-ray spectrum extracted from the
ring-like structure is also represented by an absorbed thin thermal plasma
model (kT_e \sim 0.9 keV). The thermal energy of the plasma filling the
ring-like structure is estimated to be 1.0 \times 10^{51} erg. We therefore
propose that the two sources comprise a single ring-like object, which is
possibly a super bubble with a size of 49 pc \times 40 pc in the Galactic
center region.Comment: 9 pages, 7 figures, accepted for publication in PAS
An Apparent Hard X-ray Decline of CH Cygni
CH Cygni is a symbiotic star consisting of an M giant and an accreting white
dwarf, which is known to be a highly variable X-ray source with a complex,
two-component, spectra. Here we report on two Suzaku observations of CH Cyg,
taken in 2006 January and May, during which the system was seen to be in a soft
X-ray bright, hard X-ray faint state. Based on the extraordinary strength of
the 6.4 keV fluorescent Fe K-alpha line, we show that the hard X-rays observed
with Suzaku are dominated by scattering.Comment: 8 pages, 4 figures, accepted by Publications of the Astronomical
Society of Japa
Effect of 1,2-Dimethylhydrazine and Hydrogen Peroxide for the Duodenal Tumorigenesis in Relation to Blood Catalase Activity in Mice
Three different mouse strains, C3H/C^b_s C3H/HeN and B6C3 (C57BL x C3H) F1, having low, high and moderate catalase activities, were studied for duodenal tumorigenesis by the combined treatment with 1,2-dimethylhydrazine (DMH)* and hydrogen peroxide (HPO). DMH alone rarely induced duodenal tumors. Administration of HPO into 3 different mouse strains induced different frequencies of duodenal tumors ; 91.7% in C3H/C^b_s 9.5% in C3H/HeN and 31.8% in B6C3F1 mice. The incidence of duodenal tumors was significantly increased to 52.6% and 93.8% both in C3H/HeN and B6C3F1 mice by the combined administration of DMH and HPO. These increases in duodenal tumor were inversely correlated with the finding that administration of DMH or HPO alone or combined treatment of DMH and HPO significantly decreased mean blood catalase activities both in C3H and B6C3F1 mice
Gravitational Redshift Detection from the Magnetic White Dwarf Harbored in RX J1712.6-2414
Gravitational redshift is a fundamental parameter that allows us to determine
the mass-to-radius ratio of compact stellar objects, such as black holes,
neutron stars, and white dwarfs (WDs). In the X-ray spectra of the close binary
system, RX J1712.62414, obtained from the Chandra High-Energy Transmission
Grating observation, we detected significant redshifts for characteristic
X-rays emitted from hydrogen-like magnesium, silicon (), and sulfur () ions, which are over the instrumental absolute energy accuracy
(). Considering some possible
factors, such as Doppler shifts associated with the plasma flow, systemic
velocity, and optical depth, we concluded that the major contributor to the
observed redshift is the gravitational redshift of the WD harbored in the
binary system, which is the first gravitational redshift detection from a
magnetic WD. Moreover, the gravitational redshift provides us with a new method
of the WD mass measurement by invoking the plasma-flow theory with strong
magnetic fields in close binaries. Regardless of large uncertainty, our new
method estimated the WD mass to be .Comment: 13 pages, 5 figures. Accepted for publication in Ap
Introduction of a Probabilistic Language Model to Non-Factoid Question-Answering Using Example Q&A Pairs
Real-time Motion Generation and Data Augmentation for Grasping Moving Objects with Dynamic Speed and Position Changes
While deep learning enables real robots to perform complex tasks had been
difficult to implement in the past, the challenge is the enormous amount of
trial-and-error and motion teaching in a real environment. The manipulation of
moving objects, due to their dynamic properties, requires learning a wide range
of factors such as the object's position, movement speed, and grasping timing.
We propose a data augmentation method for enabling a robot to grasp moving
objects with different speeds and grasping timings at low cost. Specifically,
the robot is taught to grasp an object moving at low speed using teleoperation,
and multiple data with different speeds and grasping timings are generated by
down-sampling and padding the robot sensor data in the time-series direction.
By learning multiple sensor data in a time series, the robot can generate
motions while adjusting the grasping timing for unlearned movement speeds and
sudden speed changes. We have shown using a real robot that this data
augmentation method facilitates learning the relationship between object
position and velocity and enables the robot to perform robust grasping motions
for unlearned positions and objects with dynamically changing positions and
velocities
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