442 research outputs found
Suzaku observation of the giant radio galaxy 3C 326
A Suzaku observation of a giant radio galaxy, 3C 326, which has a physical
size of about 2 Mpc, was conducted on 2008 January 19 -- 21. In addition to
several X-ray sources, diffuse emission was significantly detected associated
with its west lobe, but the east lobe was contaminated by an unidentified X-ray
source WARP J1552.4+2007. After careful evaluation of the X-ray and Non X-ray
background, the 0.4 -- 7 keV X-ray spectrum of the west lobe is described by a
power-law model. The photon index and 1 keV flux density was derived as
and nJy,
respectively, where the first and second errors represent the statistical and
systematic ones. The diffuse X-rays were attributed to be inverse Compton
radiation by the synchrotron radio electrons scattering off the cosmic
microwave background photons. This radio galaxy is the largest among those with
lobes detected through inverse Compton X-ray emission. A comparison of the
radio to X-ray fluxes yields the energy densities of electron and magnetic
field as ergs/cm3 and ergs/cm3, respectively. The galaxy
is suggested to host a low luminosity nucleus with an absorption-corrected 2 --
10 keV luminosity of ergs/s, together with a relatively
weak radio core. The energetics in the west lobe of 3C 326 were compared with
those of moderate radio galaxies with a size of kpc. The west lobe
of 3C 326 is confirmed to agree with the correlations for the moderate radio
galaxies, and , where
is their total physical size. This implies that the lobes of 3C 326 are
still being energized by the jet, despite the current weakness of the nucleus.Comment: 11 pages, 10 figures, 6 tables, Accepted for ApJ (v706 issue
The diet and feeding behavior of the black-and-white colobus (Colobus guereza) in the Kalinzu Forest, Uganda
One of the goals for primate feeding ecology is to understand the factors that affect inter- and intra-specific variations. Therefore, a detailed description of basic feeding ecology in as many populations as possible is necessary and warrants further understanding. The black-and-white colobus (Colobus guereza) or guereza is widely distributed in Africa and is one of the well-studied colobines in terms of their feeding; they demonstrate considerable variation in their diets in response to local conditions. We studied the diet of a group of guerezas in the Kalinzu Forest, Uganda, for over 30 consecutive months using behavioral observation (4308 h in total), phenology, and vegetation surveys. A total of 31 plant species were consumed by the study group. This study group was predominantly folivorous; the majority of their feeding time was involved in feeding on young leaves (87%). However, during certain times of the year, fruits and seeds accounted for 45% of monthly feeding time. Young leaves of Celtis durandii were by far the most important food, which constituted 58% of the total feeding records. There was a significant increase in the consumption of fruits and flowers once young leaf availability was low, but their consumption of fruits did not significantly increase even when fruit availability was high. Their monthly dietary diversity increased as the number of available plants with young leaves declined, suggesting that much of the dietary diversity in the study group may be attributable to the young leaf portion of their diet. Our findings may help contribute to a better understanding of the dietary adaptations and feeding ecology of guerezas in response to local environmental conditions
Detection of Asymptomatic Cardiac Metastasis and Successful Salvage Chemotherapy Comprising a Prednisone, Etoposide, Procarbazine, and Cyclophosphamide Regimen in an Elderly Japanese Patient Suffering from a Delayed Recurrence of Diffuse Large B-Cell Lymphoma
We report a case of facial diffuse large B-cell lymphoma (DLBCL) associated with recurrent metastasis in the heart and other sites in a 76-year-old Japanese woman. Initially, she developed DLBCL in her left upper eyelid that spread into the left orbit (Ann Arbor classification stage I). The lesion went into clinical regression after 4 cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy followed by radiotherapy. More than 3 years later, the lymphoma recurred in her facial skin, together with metastases in the mediastinal lymph nodes and the heart; the tumor in the heart was successfully detected by PET/CT and cardiac MRI. To treat the recurrent lesions, we performed a salvage chemotherapy regimen comprising prednisone, etoposide, procarbazine, and cyclophosphamide, which successfully induced tumor regression
ALMA ACA detection of submillimeter emission associated with the west hot spot of the radio galaxy Pictor A
In order to investigate the far-infrared excess detected from the west hot
spot of the radio galaxy Pictor A with the Herschel observatory, a
submillimeter photometry is performed with the Atacama Compact Array (ACA) of
the Atacama Large Millimeter/submillimeter Array at Band 8 with the reference
frequency of 405 GHz. A submillimeter source is discovered at the radio peak of
the hot spot. Because the 405 GHz flux density of the source, mJy,
agrees with the extrapolation of the synchrotron radio spectrum, the
far-infrared excess is suggested to exhibit no major contribution at the ACA
band. In contrast, by subtracting the power-law spectrum tightly constrained by
the radio and ACA data, the significance of the excess in the Herschel band is
well confirmed. No diffuse submillimeter emission is detected within the ACA
field of view, and thus, the excess is ascribed to the west hot spot itself. In
comparison to the previous estimate based on the Herschel data, the relative
contribution of the far-infrared excess is reduced by a factor of .
The spectrum of the excess below the far-infrared band is determined to be
harder than that of the diffusive shock acceleration. This strengthens the
previous interpretation that the excess originates via the magnetic turbulence
in the substructures within the hot spot. The ACA data are utilized to evaluate
the magnetic field strength of the excess and of diffuse radio structure
associated to the hot spot.Comment: 10 pages,4 figures, 3 tables, accepted for Ap
Pancreatic β Cell–specific Expression of Thioredoxin, an Antioxidative and Antiapoptotic Protein, Prevents Autoimmune and Streptozotocin-induced Diabetes
The cytotoxicity of reactive oxygen intermediates (ROIs) has been implicated in the destruction of pancreatic β cells in insulin-dependent diabetes mellitus (IDDM). Thioredoxin (TRX), a redox (reduction/oxidation)-active protein, has recently been shown to protect cells from oxidative stress and apoptosis. To elucidate the roles of oxidative stress in the development of autoimmune diabetes in vivo, we produced nonobese diabetic transgenic mice that overexpress TRX in their pancreatic β cells. In these transgenic mice, the incidence of diabetes was markedly reduced, whereas the development of insulitis was not prevented. Moreover, induction of diabetes by streptozotocin, an ROI-generating agent, was also attenuated by TRX overexpression in β cells. This is the first direct demonstration that an antioxidative and antiapoptotic protein protects β cells in vivo against both autoimmune and drug-induced diabetes. Our results strongly suggest that oxidative stress plays an essential role in the destruction of β cells by infiltrating inflammatory cells in IDDM
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