275 research outputs found
Suzaku wide-band X-ray Spectroscopy of the Seyfert 2 AGN in NGC 4945
Suzaku observed a nearby Seyfert 2 galaxy NGC4945, which hosts one of the
brightest active galactic nuclei above 20 keV. Combining data from the X-ray
CCD camera (XIS) and the Hard X-ray Detector (HXD), the AGN intrinsic nuclear
emission and its reprocessed signals were observed simultaneously. The
intrinsic emission is highly obscured with an absorbing column of cm, and was detectable only above keV. The
spectrum below 10 keV is dominated by reflection continuum and emission lines
from neutral/ionized material. Along with a neutral iron K line, a
neutral iron K and a neutral nickel K line were detected for the
first time from this source. The neutral lines and the cold reflection
continuum are consistent with both originating in the same location. The
Compton down-scattered shoulder in the neutral Fe-K line is
in flux of the narrow core, which confirms that the line originates from
reflection rather than transmission. The weakness of the Compton shoulder also
indicates that the reflector is probably seen nearly edge-on. Flux of the
intrinsic emission varied by a factor of within ks, which
requires the obscuring material to be geometrically thin. Broadband spectral
modeling showed that the solid angle of the neutral reflector is less than a
few . All this evidence regarding the reprocessed
signals suggests that a disk-like absorber/reflector is viewed from a near
edge-on angle.Comment: 11 pages, 11 figure
Suzaku Observation of the Brightest Broad-Line Radio Galaxy 4C 50.55 (IGR J 21247+5058)
We report the results from a deep Suzaku observation of 4C 50.55 (IGR J
21247+5058), the brightest broad-line radio galaxy in the hard X-ray (> 10 keV)
sky. The simultaneous broad band spectra over 1-60 keV can be represented by a
cut-off power law with two layers of absorption and a significant reflection
component from cold matter with a solid angle of \Omega/2\pi \approx 0.2. A
rapid flux rise by ~ 20% over 2 \times 10^4 sec is detected in the 2-10 keV
band. The spectral energy distribution suggests that there is little
contribution to the total X-ray emission from jets. Applying a thermal
Comptonization model, we find that corona is optically thick (\tau_e \approx 3)
and has a relatively low temperature (kT_e \approx 30 keV). The narrow iron-K
emission line is consistent with a picture where the standard disk is truncated
and/or its inner part is covered by optically thick Comptonizing corona
smearing out relativistic broad line features. The inferred disk structure may
be a common feature of accretion flows onto black holes that produce powerful
jets.Comment: 8 pages, 7 figure
Neural Activity Changes Underlying the Working Memory Deficit in Alpha-CaMKII Heterozygous Knockout Mice
The alpha-isoform of calcium/calmodulin-dependent protein kinase II (α-CaMKII) is expressed abundantly in the forebrain and is considered to have an essential role in synaptic plasticity and cognitive function. Previously, we reported that mice heterozygous for a null mutation of α-CaMKII (α-CaMKII+/−) have profoundly dysregulated behaviors including a severe working memory deficit, which is an endophenotype of schizophrenia and other psychiatric disorders. In addition, we found that almost all the neurons in the dentate gyrus (DG) of the mutant mice failed to mature at molecular, morphological and electrophysiological levels. In the present study, to identify the brain substrates of the working memory deficit in the mutant mice, we examined the expression of the immediate early genes (IEGs), c-Fos and Arc, in the brain after a working memory version of the eight-arm radial maze test. c-Fos expression was abolished almost completely in the DG and was reduced significantly in neurons in the CA1 and CA3 areas of the hippocampus, central amygdala, and medial prefrontal cortex (mPFC). However, c-Fos expression was intact in the entorhinal and visual cortices. Immunohistochemical studies using arc promoter driven dVenus transgenic mice demonstrated that arc gene activation after the working memory task occurred in mature, but not immature neurons in the DG of wild-type mice. These results suggest crucial insights for the neural circuits underlying spatial mnemonic processing during a working memory task and suggest the involvement of α-CaMKII in the proper maturation and integration of DG neurons into these circuits
A Large Hepatic Cyst with Obstructive Jaundice Successfully Treated with Single-Incision Laparoscopic Deroofing
We herein present a case of hepatic cysts causing obstructive jaundice that was treated with single-incision laparoscopic deroofing. A 72-year-old female patient was referred to hospital due to a large hepatic cyst that compressed the intrahepatic bile ducts. The patient was scheduled to undergo single-incision laparoscopic deroofing. The EZ ACCESS? oval type (Hakko Co. Ltd.) was placed at the umbilicus using a 25-mm incision with two 5-mm trocars. An additional 12-mm port was placed at the left epigastric region. We unroofed and excised the cyst wall using a vessel sealing system in liver segment 4. After surgery, the patient was found to be asymptomatic. The unroofed cysts were completely diminished. Notably, the remnant liver had fairly regenerated. The estimated regeneration volume of the normal liver was 153 cm3. To prevent surgical complications, clinicians should perform adequate management and use of devices. To prevent postoperative recurrence of cysts, performing complete deroofing is essential. Single-incision laparoscopic deroofing contributes to improving the quality of life of patients and should be considered a standard treatment
Acute appendicitis in a rheumatoid arthritis patient treated with tocilizumab: report of a case
A 55-year-old woman had been treated for rheumatoid arthritis with tocilizumab 1 month prior to the onset of mild abdominal pain. Computed tomography revealed swelling of the appendix and ascites around the appendix. She was diagnosed with acute appendicitis and underwent emergency surgery. Although her symptoms and laboratory data indicated mild infection, surgery was conducted because of the computed tomography findings and because we believed that the physical findings and laboratory data were not dependable due to the tocilizumab.Upon surgery, a perforated inflamed appendix and abscess formation around the appendix were confirmed. Tocilizumab, which is relatively new, may conceal signs of infection or dull response to tests such as the Blumberg sign for peritonitis. It should be widely noted that the physical findings and laboratory data of patients with abdominal distress under tocilizumab treatment may be misleading
Exact and microscopic one-instanton calculations in N=2 supersymmetric Yang-Mills theories
We study the low-energy effective theory in N=2 super Yang-Mills theories by
microscopic and exact approaches. We calculate the one-instanton correction to
the prepotential for any simple Lie group from the microscopic approach. We
also study the Picard-Fuchs equations and their solutions in the semi-
classical regime for classical gauge groups with rank r \leq 3. We find that
for gauge groups G=A_r, B_r, C_r (r \leq 3) the microscopic results agree with
those from the exact solutions.Comment: 34 pages, LaTe
MAXI GSC observations of a spectral state transition in the black hole candidate XTE J1752-223
We present the first results on the black hole candidate XTE J1752-223 from
the Gas Slit Camera (GSC) on-board the Monitor of All-sky X-ray Image (MAXI) on
the International Space Station. Including the onset of the outburst reported
by the Proportional Counter Array on-board the Rossi X-ray Timing Explorer on
2009 October 23, the MAXI/GSC has been monitoring this source approximately 10
times per day with a high sensitivity in the 2-20 keV band. XTE J1752-223 was
initially in the low/hard state during the first 3 months. An anti-correlated
behavior between the 2-4 keV and 4-20 keV bands were observed around January
20, 2010, indicating that the source exhibited the spectral transition to the
high/soft state. A transient radio jet may have been ejected when the source
was in the intermediate state where the spectrum was roughly explained by a
power-law with a photon index of 2.5-3.0. The unusually long period in the
initial low/hard state implies a slow variation in the mass accretion rate, and
the dramatic soft X-ray increase may be explained by a sudden appearance of the
accretion disk component with a relatively low innermost temperature (0.4-0.7
keV). Such a low temperature might suggest that the maximum accretion rate was
just above the critical gas evaporation rate required for the state transition.Comment: Publication of Astronomical Society of Japan Vol.62, No.5 (2010) [in
print
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