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  • 1
    Publication Date: 2013-07-14
    Description: We present an investigation into how well the properties of the accretion flow on to a supermassive black hole may be coupled to those of the overlying hot corona. To do so, we specifically measure the characteristic spectral index, , of a power-law energy distribution, over an energy range of 2–10 keV, for X-ray selected, broad-lined radio-quiet active galactic nuclei (AGN) up to z  ~ 2 in Cosmic Evolution Survey (COSMOS) and Extended Chandra Deep Field South (E-CDF-S). We test the previously reported dependence between and black hole mass, full width at half-maximum (FWHM) and Eddington ratio using a sample of AGN covering a broad range in these parameters based on both the Mg  ii and Hα emission lines with the later afforded by recent near-infrared spectroscopic observations using Subaru/Fibre Multi Object Spectrograph. We calculate the Eddington ratios, Edd , for sources where a bolometric luminosity ( L Bol ) has been presented in the literature, based on spectral energy distribution fitting, or, for sources where these data do not exist, we calculate L Bol using a bolometric correction to the X-ray luminosity, derived from a relationship between the bolometric correction and L X / L 3000 . From a sample of 69 X-ray bright sources (〉250 counts), where can be measured with greatest precision, with an estimate of L Bol , we find a statistically significant correlation between and Edd , which is highly significant with a chance probability of 6.59 x 10 –8 . A statistically significant correlation between and the FWHM of the optical lines is confirmed, but at lower significance than with Edd indicating that Edd is the key parameter driving conditions in the corona. Linear regression analysis reveals that  = (0.32 ± 0.05) log 10 Edd  + (2.27 ± 0.06) and  = (–0.69 ± 0.11) log 10 (FWHM/km s –1 ) + (4.44 ± 0.42). Our results on – Edd are in very good agreement with previous results. While the – Edd relationship means that X-ray spectroscopy may be used to estimate black hole accretion rate, considerable dispersion in the correlation does not make this viable for single sources, however could be valuable for large X-ray spectral samples, such as those to be produced by eROSITA .
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 2
    Publication Date: 2014-08-19
    Description: Author(s): A. Doi, J. Fujioka, T. Fukuda, S. Tsutsui, D. Okuyama, Y. Taguchi, T. Arima, A. Q. R. Baron, and Y. Tokura We have investigated the dynamics of spin-state crossover (SSC) for perovskite LaCoO3 through optical phonons by means of infrared and inelastic x-ray spectroscopy. Upon thermally induced SSC, anomalously dispersionless Co-O bond stretching phonons coupled to the thermally excited spin state have be... [Phys. Rev. B 90, 081109] Published Mon Aug 18, 2014
    Keywords: Electronic structure and strongly correlated systems
    Print ISSN: 1098-0121
    Electronic ISSN: 1095-3795
    Topics: Physics
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  • 3
    Publication Date: 2010-08-20
    Description: Epigenetic modifications must underlie lineage-specific differentiation as terminally differentiated cells express tissue-specific genes, but their DNA sequence is unchanged. Haematopoiesis provides a well-defined model to study epigenetic modifications during cell-fate decisions, as multipotent progenitors (MPPs) differentiate into progressively restricted myeloid or lymphoid progenitors. Although DNA methylation is critical for myeloid versus lymphoid differentiation, as demonstrated by the myeloerythroid bias in Dnmt1 hypomorphs, a comprehensive DNA methylation map of haematopoietic progenitors, or of any multipotent/oligopotent lineage, does not exist. Here we examined 4.6 million CpG sites throughout the genome for MPPs, common lymphoid progenitors (CLPs), common myeloid progenitors (CMPs), granulocyte/macrophage progenitors (GMPs), and thymocyte progenitors (DN1, DN2, DN3). Marked epigenetic plasticity accompanied both lymphoid and myeloid restriction. Myeloid commitment involved less global DNA methylation than lymphoid commitment, supported functionally by myeloid skewing of progenitors following treatment with a DNA methyltransferase inhibitor. Differential DNA methylation correlated with gene expression more strongly at CpG island shores than CpG islands. Many examples of genes and pathways not previously known to be involved in choice between lymphoid/myeloid differentiation have been identified, such as Arl4c and Jdp2. Several transcription factors, including Meis1, were methylated and silenced during differentiation, indicating a role in maintaining an undifferentiated state. Additionally, epigenetic modification of modifiers of the epigenome seems to be important in haematopoietic differentiation. Our results directly demonstrate that modulation of DNA methylation occurs during lineage-specific differentiation and defines a comprehensive map of the methylation and transcriptional changes that accompany myeloid versus lymphoid fate decisions.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2956609/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2956609/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ji, Hong -- Ehrlich, Lauren I R -- Seita, Jun -- Murakami, Peter -- Doi, Akiko -- Lindau, Paul -- Lee, Hwajin -- Aryee, Martin J -- Irizarry, Rafael A -- Kim, Kitai -- Rossi, Derrick J -- Inlay, Matthew A -- Serwold, Thomas -- Karsunky, Holger -- Ho, Lena -- Daley, George Q -- Weissman, Irving L -- Feinberg, Andrew P -- CA09151/CA/NCI NIH HHS/ -- F32 AI058521/AI/NIAID NIH HHS/ -- F32 AI058521-02/AI/NIAID NIH HHS/ -- F32AI058521/AI/NIAID NIH HHS/ -- P50 HG003233/HG/NHGRI NIH HHS/ -- P50 HG003233-07/HG/NHGRI NIH HHS/ -- P50 HG003233-08/HG/NHGRI NIH HHS/ -- P50HG003233/HG/NHGRI NIH HHS/ -- R00 AG029760/AG/NIA NIH HHS/ -- R00 AG029760-04/AG/NIA NIH HHS/ -- R00AGO29760/PHS HHS/ -- R01 AI047457/AI/NIAID NIH HHS/ -- R01 AI047457-04/AI/NIAID NIH HHS/ -- R01 AI047457-05/AI/NIAID NIH HHS/ -- R01 AI047458/AI/NIAID NIH HHS/ -- R01 CA086065/CA/NCI NIH HHS/ -- R01 GM083084/GM/NIGMS NIH HHS/ -- R01 GM083084-04/GM/NIGMS NIH HHS/ -- R01AI047457/AI/NIAID NIH HHS/ -- R01AI047458/AI/NIAID NIH HHS/ -- R37 CA054358/CA/NCI NIH HHS/ -- R37 CA054358-18/CA/NCI NIH HHS/ -- R37 CA054358-19/CA/NCI NIH HHS/ -- R37CA053458/CA/NCI NIH HHS/ -- England -- Nature. 2010 Sep 16;467(7313):338-42. doi: 10.1038/nature09367. Epub 2010 Aug 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Epigenetics and Department of Medicine, Johns Hopkins University School of Medicine, 570 Rangos, 725 N. Wolfe St., Baltimore, Maryland 21205, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20720541" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Line ; *Cell Lineage/genetics ; CpG Islands/genetics ; *DNA Methylation/genetics ; Epigenesis, Genetic ; Gene Expression Profiling ; Genome/genetics ; *Hematopoiesis/genetics ; Hematopoietic Stem Cells/*cytology/*metabolism ; Lymphocytes/cytology/metabolism ; Metabolome ; Metabolomics ; Mice ; Myeloid Cells/cytology/metabolism ; Pluripotent Stem Cells/cytology/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2011-09-09
    Description: Powerful radio jets from active galactic nuclei are thought to be powered by the accretion of material onto the supermassive black hole (the 'central engine'). M87 is one of the closest examples of this phenomenon, and the structure of its jet has been probed on a scale of about 100 Schwarzschild radii (R(s), the radius of the event horizon). However, the location of the central black hole relative to the jet base (a bright compact radio 'core') remains elusive. Observations of other jets indicate that the central engines are located about 10(4)-10(6)R(s) upstream from the radio core. Here we report radio observations of M87 at six frequencies that allow us to achieve a positional accuracy of about 20 microarcseconds. As the jet base becomes more transparent at higher frequencies, the multifrequency position measurements of the radio core enable us to determine the upstream end of the jet. The data reveal that the central engine of M87 is located within 14-23R(s) of the radio core at 43 GHz. This implies that the site of material infall onto the black hole and the eventual origin of the jet reside in the bright compact region seen on the image at 43 GHz.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hada, Kazuhiro -- Doi, Akihiro -- Kino, Motoki -- Nagai, Hiroshi -- Hagiwara, Yoshiaki -- Kawaguchi, Noriyuki -- England -- Nature. 2011 Sep 7;477(7363):185-7. doi: 10.1038/nature10387.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan. kazuhiro.hada@nao.ac.jp〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21901008" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 2010-07-21
    Description: Somatic cell nuclear transfer and transcription-factor-based reprogramming revert adult cells to an embryonic state, and yield pluripotent stem cells that can generate all tissues. Through different mechanisms and kinetics, these two reprogramming methods reset genomic methylation, an epigenetic modification of DNA that influences gene expression, leading us to hypothesize that the resulting pluripotent stem cells might have different properties. Here we observe that low-passage induced pluripotent stem cells (iPSCs) derived by factor-based reprogramming of adult murine tissues harbour residual DNA methylation signatures characteristic of their somatic tissue of origin, which favours their differentiation along lineages related to the donor cell, while restricting alternative cell fates. Such an 'epigenetic memory' of the donor tissue could be reset by differentiation and serial reprogramming, or by treatment of iPSCs with chromatin-modifying drugs. In contrast, the differentiation and methylation of nuclear-transfer-derived pluripotent stem cells were more similar to classical embryonic stem cells than were iPSCs. Our data indicate that nuclear transfer is more effective at establishing the ground state of pluripotency than factor-based reprogramming, which can leave an epigenetic memory of the tissue of origin that may influence efforts at directed differentiation for applications in disease modelling or treatment.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3150836/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3150836/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kim, K -- Doi, A -- Wen, B -- Ng, K -- Zhao, R -- Cahan, P -- Kim, J -- Aryee, M J -- Ji, H -- Ehrlich, L I R -- Yabuuchi, A -- Takeuchi, A -- Cunniff, K C -- Hongguang, H -- McKinney-Freeman, S -- Naveiras, O -- Yoon, T J -- Irizarry, R A -- Jung, N -- Seita, J -- Hanna, J -- Murakami, P -- Jaenisch, R -- Weissleder, R -- Orkin, S H -- Weissman, I L -- Feinberg, A P -- Daley, G Q -- CA86065/CA/NCI NIH HHS/ -- DP1 OD000256/OD/NIH HHS/ -- DP1 OD000256-01/OD/NIH HHS/ -- HL099999/HL/NHLBI NIH HHS/ -- K99 HL093212/HL/NHLBI NIH HHS/ -- K99 HL093212-01/HL/NHLBI NIH HHS/ -- K99 HL093212-02/HL/NHLBI NIH HHS/ -- K99HL093212-01/HL/NHLBI NIH HHS/ -- P50HG003233/HG/NHGRI NIH HHS/ -- R01 CA086065/CA/NCI NIH HHS/ -- R01 DK059279/DK/NIDDK NIH HHS/ -- R01 DK059279-02/DK/NIDDK NIH HHS/ -- R01 DK059279-10/DK/NIDDK NIH HHS/ -- R01 DK070055/DK/NIDDK NIH HHS/ -- R01 DK070055-01/DK/NIDDK NIH HHS/ -- R01 GM083084/GM/NIGMS NIH HHS/ -- R01 GM083084-04/GM/NIGMS NIH HHS/ -- R01-DK59279/DK/NIDDK NIH HHS/ -- R01-DK70055/DK/NIDDK NIH HHS/ -- R01AI047457/AI/NIAID NIH HHS/ -- R01AI047458/AI/NIAID NIH HHS/ -- R37 HD045022/HD/NICHD NIH HHS/ -- R37CA054358/CA/NCI NIH HHS/ -- RC2 HL102815/HL/NHLBI NIH HHS/ -- RC2 HL102815-01/HL/NHLBI NIH HHS/ -- RC2-HL102815/HL/NHLBI NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2010 Sep 16;467(7313):285-90. doi: 10.1038/nature09342.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Stem Cell Transplantation Program, Division of Pediatric Hematology/Oncology, Manton Center for Orphan Disease Research, Howard Hughes Medical Institute, Children's Hospital Boston and Dana Farber Cancer Institute, Boston, Massachusetts 02115, USA〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20644535" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cell Differentiation/genetics ; Cell Lineage/genetics ; Cellular Reprogramming/genetics ; DNA Methylation/genetics ; Embryonic Stem Cells/cytology/metabolism ; *Epigenesis, Genetic ; Genome/genetics ; Hematopoietic Stem Cells/cytology/metabolism ; Induced Pluripotent Stem Cells/*cytology/*metabolism ; Mice ; Mice, Inbred C57BL ; Mice, Inbred CBA ; Nuclear Transfer Techniques ; Transcription Factors/genetics/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2011-02-28
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
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  • 7
  • 8
    Publication Date: 2014-07-15
    Description: A 12 × 12 pixel detector has been developed and used in a laboratory experiment for lost fast-ion diagnostics. With gamma rays in the MeV range originating from nuclear reactions 9 Be(α, nγ) 12 C, 9 Be(d, nγ) 12 C, and 12 C(d, pγ) 13 C, a high purity germanium (HPGe) detector measured a fine-energy-resolved spectrum of gamma rays. The HPGe detector enables the survey of background-gamma rays and Doppler-shifted photo peak shapes. In the experiments, the pixel detector produces a gamma-ray image reconstructed from the energy spectrum obtained from total photon counts of irradiation passing through the detector's lead collimator. From gamma-ray image, diagnostics are able to produce an analysis of the fast ion loss onto the first wall in principle.
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
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  • 9
    Publication Date: 2013-07-04
    Description: We report on multifrequency observations of the -ray emitting narrow-line Seyfert 1 galaxy PKS 1502+036 performed from radio to -rays during 2008 August–2012 November by Fermi -Large Area Telescope (LAT), Swift (X-ray Telescope and Ultraviolet/Optical Telescope), Owens Valley Radio Observatory, Very Long Baseline Array (VLBA) and Very Large Array. No significant variability has been observed in -rays, with 0.1–100 GeV flux that ranged between (3–7)  x 10 –8 ph cm –2  s –1 using 3-month time bins. The photon index of the LAT spectrum ( = 2.60 ± 0.06) and the apparent isotropic -ray luminosity ( L 0.1-100 GeV  = 7.8  x 10 45  erg s –1 ) over 51 months are typical of a flat spectrum radio quasar. The radio spectral variability and the one-sided structure, in addition to the observed -ray luminosity, suggest a relativistic jet with a high Doppler factor. In contrast to SBS 0846+513, the VLBA at 15 GHz did not observe superluminal motion for PKS 1502+036. Despite having the optical characteristics typical of a narrow-line Seyfert 1 galaxy, radio and -ray properties of PKS 1502+036 are found to be similar to those of a blazar at the low end of the black hole mass distribution for blazars. This is in agreement with what has been found in the case of the other -ray emitting narrow-line Seyfert 1 SBS 0846+513.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 10
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