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SPACE TELESCOPE AND OPTICAL REVERBERATION MAPPING PROJECT.VI. REVERBERATING DISK MODELS FOR NGC 5548
Starkey, D.,Horne, Keith,Fausnaugh, M. M.,Peterson, B. M.,Bentz, M. C.,Kochanek, C. S.,Denney, K. D.,Edelson, R.,Goad, M. R.,Rosa, G. De,Anderson, M. D.,Aré,valo, P.,Barth, A. J.,Bazhaw, C.,Borm American Astronomical Society 2017 The Astrophysical journal Vol.835 No.1
<P>We conduct a multiwavelength continuum variability study of the Seyfert 1 galaxy NGC 5548 to investigate the temperature structure of its accretion disk. The 19 overlapping continuum light curves (1158 angstrom to 9157 angstrom) combine simultaneous Hubble Space Telescope, Swift, and ground-based observations over a 180 day period from 2014 January to July. Light-curve variability is interpreted as the reverberation response of the accretion disk to irradiation by a central time-varying point source. Our model yields the disk inclination i = 36 degrees +/- 10 degrees, temperature T-1= (44 +/- 6) x 10(3) K at 1 light day from the black hole, and a temperature-radius slope (T proportional to r(-alpha)) of alpha = 0.99 +/- 0.03. We also infer the driving light curve and find that it correlates poorly with both the hard and soft X-ray light curves, suggesting that the X-rays alone may not drive the ultraviolet and optical variability over the observing period. We also decompose the light curves into bright, faint, and mean accretion-disk spectra. These spectra lie below that expected for a standard blackbody accretion disk accreting at L/L-Edd = 0.1.</P>
Kakuda, Saya,Peterson, Ryan L.,Ohkubo, Kei,Karlin, Kenneth D.,Fukuzumi, Shunichi American Chemical Society 2013 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.135 No.17
<P>A copper complex, [(PV-tmpa)Cu<SUP>II</SUP>](ClO<SUB>4</SUB>)<SUB>2</SUB> (<B>1</B>) [PV-tmpa = bis(pyrid-2-ylmethyl){[6-(pivalamido)pyrid-2-yl]methyl}amine], acts as a more efficient catalyst for the four-electron reduction of O<SUB>2</SUB> by decamethylferrocene (Fc*) in the presence of trifluoroacetic acid (CF<SUB>3</SUB>COOH) in acetone as compared with the corresponding copper complex without a pivalamido group, [(tmpa)Cu<SUP>II</SUP>](ClO<SUB>4</SUB>)<SUB>2</SUB> (<B>2</B>) (tmpa = tris(2-pyridylmethyl)amine). The rate constant (<I>k</I><SUB>obs</SUB>) of formation of decamethylferrocenium ion (Fc*<SUP>+</SUP>) in the catalytic four-electron reduction of O<SUB>2</SUB> by Fc* in the presence of a large excess CF<SUB>3</SUB>COOH and O<SUB>2</SUB> obeyed first-order kinetics. The <I>k</I><SUB>obs</SUB> value was proportional to the concentration of catalyst <B>1</B> or <B>2</B>, whereas the <I>k</I><SUB>obs</SUB> value remained constant irrespective of the concentration of CF<SUB>3</SUB>COOH or O<SUB>2</SUB>. This indicates that electron transfer from Fc* to <B>1</B> or <B>2</B> is the rate-determining step in the catalytic cycle of the four-electron reduction of O<SUB>2</SUB> by Fc* in the presence of CF<SUB>3</SUB>COOH. The second-order catalytic rate constant (<I>k</I><SUB>cat</SUB>) for <B>1</B> is 4 times larger than the corresponding value determined for <B>2</B>. With the pivalamido group in <B>1</B> compared to <B>2</B>, the Cu<SUP>II</SUP>/Cu<SUP>I</SUP> potentials are –0.23 and –0.05 V vs SCE, respectively. However, during catalytic turnover, the CF<SUB>3</SUB>COO<SUP>–</SUP> anion present readily binds to <B>2</B> shifting the resulting complex’s redox potential to –0.35 V. The pivalamido group in <B>1</B> is found to inhibit anion binding. The overall effect is to make <B>1</B> easier to reduce (relative to <B>2</B>) during catalysis, accounting for the relative <I>k</I><SUB>cat</SUB> values observed. <B>1</B> is also an excellent catalyst for the two-electron two-proton reduction of H<SUB>2</SUB>O<SUB>2</SUB> to water and is also more efficient than is <B>2</B>. For both complexes, reaction rates are greater than for the overall four-electron O<SUB>2</SUB>-reduction to water, an important asset in the design of catalysts for the latter.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2013/jacsat.2013.135.issue-17/ja3125977/production/images/medium/ja-2012-125977_0017.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja3125977'>ACS Electronic Supporting Info</A></P>
Ye, R. R.,Peterson, D. R.,Seemann, F.,Kitamura, S. I.,Lee, J. S.,Lau, T. C.,Tsui, S. K.,Au, D. W. Springer Science + Business Media 2017 Environmental Science and Pollution Research Vol.24 No.36
<P>Many anthropogenic pollutants in coastal marine environments can induce immune impairments in wild fish and reduce their survival fitness. There is a pressing need to establish sensitive and high throughput in vivo tools to systematically evaluate the immunosuppressive effects of contaminants in marine teleosts. This study reviewed a battery of in vivo immune function detection technologies established for different biological hierarchies at molecular (immune function pathways and genes by next generation sequencing (NGS)), cellular (leukocytes profiles by flow cytometry), tissues/organ system (whole adult histo-array), and organism (host resistance assays (HRAs)) levels, to assess the immune competence of marine medaka Oryzias melastigma. This approach enables a holistic assessment of fish immune competence under different chemical exposure or environmental scenarios. The data obtained will also be useful to unravel the underlying immunotoxic mechanisms. Intriguingly, NGS analysis of hepatic immune gene expression profiles (male > female) are in support of the bacterial HRA findings, in which infection-induced mortality was consistently higher in females than in males. As such, reproductive stages and gender-specific responses must be taken into consideration when assessing the risk of immunotoxicants in the aquatic environment. The distinct phenotypic sexual dimorphism and short generation time (3 months) of marine medaka offer additional advantages for sex-related immunotoxicological investigation.</P>
장주혁,최원호,B.J. Peterson,D.C. Seo,K. Mukai,R. Sano,S. Oh,S. H. Hong,홍주환,H.Y. Lee 한국물리학회 2018 Current Applied Physics Vol.18 No.4
Based on the two-dimensional radiation images obtained by an infrared imaging video bolometer (IRVB) with tangential view, the two dimensional radiation profiles of plasmas in KSTAR were reconstructed. The IRVB installed on KSTAR has a tangential view of the plasma, and thus tomographic reconstruction of the raw images of radiation profiles was performed to remove the chord-integration effect by using a tomographic reconstruction code based on the Phillips-Tikhonov algorithm. Phantom reconstruction tests with various synthetic images were carried out to validate the accuracy of the reconstruction results. It is found that hollow radiation phantoms with strong divertor radiation were reconstructed with high accuracy. Furthermore, the effects of the number of channels of the IR camera, and the number of pixels of the plasma and of the IRVB on reconstruction performance are studied with phantom tests. Two-dimensionally reconstructed images of KSTAR plasmas demonstrated that radiation loss at the plasma edge and near the divertor region increased significantly after gaseous impurity injection. The total radiated power was up to 1.2MWat the disruption, which was 40% of the NBI power. After argon and krypton gas injection, total radiated power was increased by 325 kW and 180 kW, respectively.
A Tc-99m SPECT study of regional cerebral blood flow in patients with transient global amnesia
Chung, Y.A.,Jeong, J.,Yang, D.W.,Kang, B.J.,Kim, S.H.,Chung, S.K.,Sohn, H.S.,Peterson, B.S. Academic Press 2009 NeuroImage Vol.47 No.1
Objectives: This study aimed to determine whether regional cerebral blood flow (rCBF) is abnormal in patients who have Transient Global Amnesia (TGA). Methods: We obtained noninvasive rCBF measurements using Tc-99m-ethyl cysteinate diamer Single Photon Emission Computed Tomography (SPECT) in 7 patients diagnosed with TGA within 4 days of onset of the amnestic episode while the patients were still symptomatic and in 17 age-matched healthy control subjects. We assessed memory functioning using the Hopkins's Verbal Learning Test (HVLT) and Statistical Parametric Mapping to compare rCBF across diagnostic groups. Results: The patients with TGA were significantly impaired in their performance on the 20-minute delayed recall of the HVLT. They also exhibited significantly decreased rCBF on their SPECT scans in the inferior and middle frontal gyrus bilaterally, with more prominent left-sided reductions in the superior temporal, precentral, and postcentral gyri, as well as increased rCBF primarily in the right hemisphere within the middle temporal, superior temporal, and inferior frontal gyri, cerebellum, and thalamus, compared with the normal control group. Conclusion: These findings suggest that lateralized abnormalities in brain functioning are an important component of the pathophysiology of TGA. Lateralized abnormalities may disrupt functions that are relatively specific to the left hemisphere, including receptive language, symbolic representation, and the processing of local features in the environment, while preserving anterograde memory processes. Increased flow to the right hemisphere centered on regions that subserve the functions of expressive language and visuospatial processing, and may represent processes that compensate for flow reductions to the left hemisphere.
THE LOW-LUMINOSITY END OF THE RADIUS-LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI
Bentz, Misty C.,Denney, Kelly D.,Grier, Catherine J.,Barth, Aaron J.,Peterson, Bradley M.,Vestergaard, Marianne,Bennert, Vardha N.,Canalizo, Gabriela,De Rosa, Gisella,Filippenko, Alexei V.,Gates, Elin IOP Publishing 2013 The Astrophysical journal Vol.767 No.2
<P>We present an updated and revised analysis of the relationship between the H beta broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of nine new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create 'AGN-free' images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the H beta time lag, which is assumed to yield the average H beta BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R-BLR-L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of alpha = 0.533(-0.033)(+0.035), consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19 +/- 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R-BLR-L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the universe to be probed by a separate population of objects, and over a larger range of redshifts.</P>
<i>Euphausia pacifica</i> brood sizes: a North Pacific synthesis
Feinberg, L. R.,Shaw, C. T.,Peterson, W. T.,Dé,cima, M.,Okazaki, Y.,Ju, S.-J. Oxford University Press 2013 Journal of plankton research Vol.35 No.6
<P><I>Euphausia pacifica</I> occupy a remarkably wide range of ecosystems. We examined the differences in brood sizes from eight regions of the North Pacific to explore how variation in the brood size might contribute to their success over such a range. We show a compilation and analysis of short-term <I>E. pacifica</I> brood size incubations from around the North Pacific rim, ranging from the Yellow Sea (YS) (Korea) to southern California (SC), USA. Brood sizes for <I>E. pacifica</I> are highly variable in all regions and range from 5 to 697 eggs overall. Median brood sizes were largest in the YS and off Newport, Oregon and the maximum brood sizes were greatest in the regions off the coasts of Oregon and Washington, USA followed by the YS. Quantile regression analysis revealed that there was a significant relationship between the female length and the maximum brood size (95% quantile) for broods from SC, Oregon, and Washington, USA as well as Toyama Bay, Japan, indicating that the maximum brood size is limited by the female length in these regions. This suggests that other factors, hydrographic conditions, food quantity/quality or physiological condition of females, may limit maximum brood sizes in the other regions examined here.</P>