A Variable Partial Covering Model for the Seyfert 1 Galaxy MCG-6-30-15

We propose a simple spectral model for the Seyfert 1 Galaxy MCG-6-30-15 that can explain most of the 1 - 40 keV spectral variation by change of the partial covering fraction, similar to the one proposed by Miller et al. (2008). Our spectral model is composed of three continuum components; (1) a direct power-law component, (2) a heavily absorbed power-law component by mildly ionized intervening matter, and (3) a cold disk reflection component far from the black hole with moderate solid-angle ({\Omega}/2{\pi} \approx 0.3) accompanying a narrow fluorescent iron line. The first two components are affected by the surrounding highly ionized thin absorber with N_H \approx 10^{23.4}cm-2 and log {\xi} \approx 3.4. The heavy absorber in the second component is fragmented into many clouds, each of which is composed of radial zones with different ionization states and column densities, the main body (N_H \approx 10^24.2cm-2, log {\xi} \approx 1.6), the envelope (N_H \approx 10^22.1cm-2, log {\xi} \approx 1.9) and presumably a completely opaque core. These parameters of the ionized absorbers, as well as the intrinsic spectral shape of the X-ray source, are unchanged at all. The central X-ray source is moderately extended, and its luminosity is not significantly variable. The observed flux and spectral variations are mostly explained by variation of the geometrical partial covering fraction of the central source from 0 (uncovered) to \sim0.63 by the intervening ionized clouds in the line of sight. The ionized iron K-edge of the heavily absorbed component explains most of the seemingly broad line-like feature, a well-known spectral characteristic of MCG-6-30-15. The direct component and the absorbed component anti-correlate, cancelling their variations each other, so that the fractional spectral variation becomes the minimum at the iron energy band; another observational characteristic of MCG-6-30-15 is thus explained.Comment: Accepted to Publications of the Astronomical Society of Japa

N-Myc-activated microRNAs Inhibit Protein Synthesis of RUNX1 and RUNX3 in Neuroblastoma Cell Lines

　RUNX1 and RUNX3 are master transcription factors in sensory neuron lineage specifications. Protein levels of such developmental regulators are tightly controlled during carcinogenesis, in order to block differentiation and drive proliferation. Here we report that neuroblastoma specific microRNAs inhibit protein syntheses of RUNX1 and RUNX3 through 3’UTR sequences. Computational prediction identified two putative binding sequences for N-Myc-activated microRNAs both in RUNX1 and RUNX3 3’UTRs. Streptavidin RNA aptamer-tagged 3’UTR sequences pulled down miR-17, miR-18a, miR-19a, miR-20a or miR-130a from neuroblastoma cell lysate. 3’UTR target protection from N-Myc-activated microRNAs increased protein synthesis of RUNX1 or RUNX3 and induced differentiation in neuroblastoma cell lines. Together, protein levels of RUNX1 and RUNX3 are post-transcriptionally regulated by N-Myc-activated microRNAs, highlighting the mutual negative feedback between N-Myc oncogene and RUNX3 tumor suppressor in neuroblastoma

Measuring Energy-saving Technological Change: International Trends and Differences

Technological change is essential for balancing economic growth and environmental sustainability. This study measures and documents energy-saving technological change to understand its trends in advanced countries over recent decades. We estimate aggregate production functions with factor-augmenting technology using cross-country panel data and shift-share instruments, thereby measuring and documenting energy-saving technological change. Our results show how energy-saving technological change varies across countries over time and the extent to which it contributes to economic growth in 12 OECD countries from the years 1978 to 2005

Derivation of the small-angle scattering profile of a target biomacromolecule from a profile deteriorated by aggregates. AUC–SAS

Aggregates cause a fatal problem in the structural analysis of a biomacromolecule in solution using small-angle X-ray or neutron scattering (SAS): they deteriorate the scattering profile of the target molecule and lead to an incorrect structure. Recently, an integrated method of analytical ultracentrifugation (AUC) and SAS, abbreviated AUC–SAS, was developed as a new approach to overcome this problem. However, the original version of AUC–SAS does not offer a correct scattering profile of the target molecule when the weight fraction of aggregates is higher than ca 10%. In this study, the obstacle point in the original AUC–SAS approach is identified. The improved AUC–SAS method is then applicable to a solution with a relatively larger weight fraction of aggregates (≤20%)