6,479 research outputs found
Influences of magnetic coupling process on the spectrum of a disk covered by the corona
Recently, much attention has been paid to the magnetic coupling (MC) process,
which is supported by very high emissivity indexes observed in Seyfert 1 galaxy
MCG-6-30-15 and GBHC XTE J1650-500. But the rotational energy transferred from
a black hole is simply assumed to be radiated away from the surrounding
accretion disk in black-body spectrum, which is obviously not consistent with
the observed hard power-law X-ray spectra. We intend to introduce corona into
the MC model to make it more compatible with the observations. We describe the
model and the procedure of a simplified Monte Carlo simulation, compare the
output spectra in the cases with and without the MC effects, and discuss the
influences of three parameters involved in the MC process on the output
spectra. It is shown that the MC process augments radiation fluxes in the UV or
X-ray band. The emergent spectrum is affected by the BH spin and magnetic field
strength at the BH horizon, while it is almost unaffected by the radial profile
of the magnetic field at the disk. Introducing corona into the MC model will
improve the fitting of the output spectra from AGNs and GBHCs.Comment: 15 pages, 5 figures, accepted by A&
Induced Growth of Asymmetric Nanocantilever Arrays on Polar Surfaces
©2003 The American Physical Society. The electronic version of this article is the complete one and can be found online at: http://link.aps.org/doi/10.1103/PhysRevLett.91.185502DOI: 10.1103/PhysRevLett.91.185502We report that the Zn-terminated ZnO (0001) polar surface is chemically active and the oxygenterminated (0001) polar surface is inert in the growth of nanocantilever arrays. Longer and wider "comblike" nanocantilever arrays are grown from the (0001)-Zn surface, which is suggested to be a self-catalyzed process due to the enrichment of Zn at the growth front. The chemically inactive
(0001)-O surface typically does not initiate any growth, but controlling experimental conditions could lead to the growth of shorter and narrower nanocantilevers from the intersections between (0001)-O with (0110) surfaces
Integrated cosparse analysis model with explicit edge inconsistency measurement for guided depth map upsampling
© 2018 SPIE and IS & T. A low-resolution depth map can be upsampled through the guidance from the registered high-resolution color image. This type of method is so-called guided depth map upsampling. Among the existing methods based on Markov random field (MRF), either data-driven or model-based prior is adopted to construct the regularization term. The data-driven prior can implicitly reveal the relation between color-depth image pair by training on external data. The model-based prior provides the anisotropic smoothness constraint guided by high-resolution color image. These types of priors can complement each other to solve the ambiguity in guided depth map upsampling. An MRF-based approach is proposed that takes both of them into account to regularize the depth map. Based on analysis sparse coding, the data-driven prior is defined by joint cosparsity on the vectors transformed from color-depth patches using the pair of learned operators. It is based on the assumption that the cosupports of such bimodal image structures computed by the operators are aligned. The edge inconsistency measurement is explicitly calculated, which is embedded into the model-based prior. It can significantly mitigate texture-copying artifacts. The experimental results on Middlebury datasets demonstrate the validity of the proposed method that outperforms seven state-of-the-art approaches
SplicingTypesAnno: Annotating and quantifying alternative splicing events for RNA-Seq data
© 2015 Elsevier Ireland Ltd. Alternative splicing plays a key role in the regulation of the central dogma. Four major types of alternative splicing have been classified as intron retention, exon skipping, alternative 5 splice sites or alternative donor sites, and alternative 3 splice sites or alternative acceptor sites. A few algorithms have been developed to detect splice junctions from RNA-Seq reads. However, there are few tools targeting at the major alternative splicing types at the exon/intron level. This type of analysis may reveal subtle, yet important events of alternative splicing, and thus help gain deeper understanding of the mechanism of alternative splicing. This paper describes a user-friendly R package, extracting, annotating and analyzing alternative splicing types for sequence alignment files from RNA-Seq. SplicingTypesAnno can: (1) provide annotation for major alternative splicing at exon/intron level. By comparing the annotation from GTF/GFF file, it identifies the novel alternative splicing sites; (2) offer a convenient two-level analysis: genome-scale annotation for users with high performance computing environment, and gene-scale annotation for users with personal computers; (3) generate a user-friendly web report and additional BED files for IGV visualization. SplicingTypesAnno is a user-friendly R package for extracting, annotating and analyzing alternative splicing types at exon/intron level for sequence alignment files from RNA-Seq
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