1,160 research outputs found
University of Dayton\u27s Endowment Growth Earns Ninth Spot Among U.S. Catholic Universities
News release announces Thomas E. Burkhardt\u27s comments on the University of Dayton\u27s endowment growth
Modeling of field singularities at dielectric edges using grid based methods
Electric field singularities at sharp metallic edges or at a dielectric
contact line can be described analytically by asymptotic expressions. The a
priori known form of the field distribution in the vicinity of these edges
can be used to construct numerical methods with improved accuracy. This
contribution focuses on a modified Finite Integration Technique and on a
Discontinuous Galerkin Method with singular approximation functions. Both
methods are able to handle field singularities at perfectly electric
conducting as well as at dielectric edges. The numerical accuracy of these
methods is investigated in a number of simulation examples including static
and dynamic field problems
UD Information Services Announces Appointment and Promotion
News release announces that Patricia Rooney has been promoted to Assignment Editor and Pamela Blumsheid has been appointed Public Affairs Coordinator
The effect of systematics on polarized spectral indices
We study four particularly bright polarized compact objects (Tau A, Virgo A,
3C273 and Fornax A) in the 7-year WMAP sky maps, with the goal of understanding
potential systematics involved in estimation of foreground spectral indices. We
estimate the spectral index, the polarization angle, the polarization fraction
and apparent size and shape of these objects when smoothed to a nominal
resolution of 1 degree FWHM. Second, we compute the spectral index as a
function of polarization orientation, alpha. Because these objects are
approximately point sources with constant polarization angle, this function
should be constant in the absence of systematics. However, computing it for the
K- and Ka-band WMAP data we find strong index variations for all four sources.
For Tau A, we find a spectral index beta=-2.59+-0.03 for alpha=30 degrees, and
beta=-2.03+-0.01 for alpha=50 degrees. On the other hand, the spectral index
between Ka and Q band is found to be stable. A simple elliptical Gaussian toy
model with parameters matching those observed in Tau A reproduces the observed
signal, and shows that the spectral index is in particular sensitive to the
detector polarization angle. Based on these findings, we first conclude that
estimation of spectral indices with the WMAP K-band polarization data at 1
degree scales is not robust. Second, we note that these issues may be of
concern for ground-based and sub-orbital experiments that use the WMAP
polarization measurements of Tau A for calibration of gain and polarization
angles.Comment: 5 pages, 6 figures, submitted to ApJ; new figure and expanded
conclusio
Deeply sequenced metagenome and metatranscriptome of a biogas-producing microbial community from an agricultural production-scale biogas plant
Bremges A, Maus I, Belmann P, et al. Deeply sequenced metagenome and metatranscriptome of a biogas-producing microbial community from an agricultural production-scale biogas plant. GigaScience. 2015;4(1): 33.Background
The production of biogas takes place under anaerobic conditions and involves microbial decomposition of organic matter. Most of the participating microbes are still unknown and non-cultivable. Accordingly, shotgun metagenome sequencing currently is the method of choice to obtain insights into community composition and the genetic repertoire.
Findings
Here, we report on the deeply sequenced metagenome and metatranscriptome of a complex biogas-producing microbial community from an agricultural production-scale biogas plant. We assembled the metagenome and, as an example application, show that we reconstructed most genes involved in the methane metabolism, a key pathway involving methanogenesis performed by methanogenic Archaea. This result indicates that there is sufficient sequencing coverage for most downstream analyses.
Conclusions
Sequenced at least one order of magnitude deeper than previous studies, our metagenome data will enable new insights into community composition and the genetic potential of important community members. Moreover, mapping of transcripts to reconstructed genome sequences will enable the identification of active metabolic pathways in target organisms
The COBE Diffuse Infrared Background Experiment Search for the Cosmic Infrared Background: IV. Cosmological Implications
In this paper we examine the cosmological constraints of the recent DIRBE and
FIRAS detection of the extragalactic background light between 125-5000 microns
on the metal and star formation histories of the universe.Comment: 38 pages and 9 figures. Accepted for publications in The
Astrophysical Journa
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