19,129 research outputs found
I Gotta Testify: Kanye West, Hip Hop, and the Church
The goal of this project, “I Gotta Testify: Kanye West, Hip Hop, and the Church,” is to add a new perspective to the scholarly discourse on Hip Hop and Christianity within classrooms, religious institutions, and popular culture by focusing on Kanye. We chose to focus on Kanye because he has been one of Hip Hop’s most influential artists in the past decade. Furthermore, Kanye is one of the most polarizing celebrities in America and across the globe. His music, fashion, political views, and family (which includes the Kardashians) dominate discourse on social media, blogs, television, and other forms of mass media. With the exception of Julius Bailey’s 2014 edited book, The Cultural Impact of Kanye West, there has been little scholarly work published on Kanye. Bailey’s book contained just one essay, written by Monica R. Miller, dedicated to the theme of Kanye and religion. We intended to produce a nontraditional journal issue, partly because Kanye has never adhered to traditional boundaries. We also chose this method because we wanted to provide a document suitable for both academic and popular audiences. Kanye West identifies as a Christian and primarily uses Christian themes in his music, videos, concerts, and messaging.
Dr. Joshua K. Wright, Dr. Adria Y. Goldman and Dr. VaNatta S. For
Free energy of formation of clusters of sulphuric acid and water molecules determined by guided disassembly
We evaluate the grand potential of a cluster of two molecular species,
equivalent to its free energy of formation from a binary vapour phase, using a
nonequilibrium molecular dynamics technique where guide particles, each
tethered to a molecule by a harmonic force, move apart to disassemble a cluster
into its components. The mechanical work performed in an ensemble of
trajectories is analysed using the Jarzynski equality to obtain a free energy
of disassembly, a contribution to the cluster grand potential. We study
clusters of sulphuric acid and water at 300 K, using a classical interaction
scheme, and contrast two modes of guided disassembly. In one, the cluster is
broken apart through simple pulling by the guide particles, but we find the
trajectories tend to be mechanically irreversible. In the second approach, the
guide motion and strength of tethering are modified in a way that prises the
cluster apart, a procedure that seems more reversible. We construct a surface
representing the cluster grand potential, and identify a critical cluster for
droplet nucleation under given vapour conditions. We compare the equilibrium
populations of clusters with calculations reported by Henschel et al. [J. Phys.
Chem. A 118, 2599 (2014)] based on optimised quantum chemical structures
The variability of the Crab Nebula in radio: No radio counterpart to gamma-ray flares
We present new Jansky Very Large Array (VLA) radio images of the Crab Nebula
at 5.5 GHz, taken at two epochs separated by 6 days about two months after a
gamma-ray flare in 2012 July. We find no significant change in the Crab's radio
emission localized to a region of <2 light-months in radius, either over the
6-day interval between our present observations or between the present
observations and ones from 2001. Any radio counterpart to the flare has a radio
luminosity of <~ times that of the nebula. Comparing our
images to one from 2001, we do however find changes in radio brightness, up to
10% in amplitude, which occur on decade timescales throughout the nebula. The
morphology of the changes is complex suggesting both filamentary and knotty
structures. The variability is stronger, and the timescales likely somewhat
shorter, nearer the centre of the nebula. We further find that even with the
excellent uv~coverage and signal-to-noise of the VLA, deconvolution errors are
much larger than the noise, being up to 1.2% of peak brightness of the nebula
in this particular case.Comment: Accepted to MNRAS; 13 pages, 6 figure
Debiasing the Minimum-Mass Extrasolar Nebula: On the Diversity of Solid Disk Profiles
A foundational idea in the theory of in situ planet formation is the "minimum
mass extrasolar nebula" (MMEN), a surface density profile () of disk
solids that is necessary to form the planets in their present locations. While
most previous studies have fit a single power-law to all exoplanets in an
observed ensemble, it is unclear whether most exoplanetary systems form from a
universal disk template. We use an advanced statistical model for the
underlying architectures of multi-planet systems to reconstruct the MMEN. The
simulated physical and Kepler-observed catalogs allows us to directly assess
the role of detection biases, and in particular the effect of non-transiting or
otherwise undetected planets, in altering the inferred MMEN. We find that
fitting a power-law of the form to each
multi-planet system results in a broad distribution of disk profiles;
g/cm and
encompass the 16th-84th percentiles of the marginal distributions in an
underlying population, where is the normalization at
AU. Around half of inner planet-forming disks have minimum solid masses of
within 1 AU. While transit observations do not tend to
bias the median , they can lead to both significantly over- and
under-estimated and thus broaden the inferred distribution of disk
masses. Nevertheless, detection biases cannot account for the full variance in
the observed disk profiles; there is no universal MMEN if all planets formed in
situ. The great diversity of solid disk profiles suggests that a substantial
fraction () of planetary systems experienced a history of
migration.Comment: Accepted to AJ. 14 pages, 6 figures, 1 table. Accompanying code is
available via SysSimPyMMEN, a pip-installable Python package (see
https://syssimpymmen.readthedocs.io/en/latest/
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Analysis of gas chromatography/mass spectrometry data for catalytic lignin depolymerization using positive matrix factorization
Various catalytic technologies are being developed to efficiently convert lignin into renewable chemicals. However, due to its complexity, catalytic lignin depolymerization often generates a wide and complex distribution of product compounds. Gas chromatography/mass spectrometry (GC-MS) is a common analytical technique to profile the compounds that comprise lignin depolymerization products. GC-MS is applied not only to determine the product composition, but also to develop an understanding of the catalytic reaction pathways and of the relationships among catalyst structure, reaction conditions, and the resulting compounds generated. Although a very useful tool, the analysis of lignin depolymerization products with GC-MS is limited by the quality and scope of the available mass spectral libraries and the ability to correlate changes in GC-MS chromatograms to changes in lignin structure, catalyst structure, and other reaction conditions. In this study, the GC-MS data of the depolymerization products generated from organosolv hybrid poplar lignin using a copper-doped porous metal oxide catalyst and a methanol/dimethyl carbonate co-solvent was analyzed by applying a factor analysis technique, positive matrix factorization (PMF). Several different solutions for the PMF model were explored. A 13-factor solution sufficiently explains the chemical changes occurring to lignin depolymerization products as a function of lignin, reaction time, catalyst, and solvent. Overall, seven factors were found to represent aromatic compounds, while one factor was defined by aliphatic compounds
Testing MONDian Dark Matter with Galactic Rotation Curves
MONDian dark matter (MDM) is a new form of dark matter quantum that naturally
accounts for Milgrom's scaling, usually associated with modified Newtonian
dynamics (MOND), and theoretically behaves like cold dark matter (CDM) at
cluster and cosmic scales. In this paper, we provide the first observational
test of MDM by fitting rotation curves to a sample of 30 local spiral galaxies
(z approximately 0.003). For comparison, we also fit the galactic rotation
curves using MOND, and CDM. We find that all three models fit the data well.
The rotation curves predicted by MDM and MOND are virtually indistinguishable
over the range of observed radii (~1 to 30 kpc). The best-fit MDM and CDM
density profiles are compared. We also compare with MDM the dark matter density
profiles arising from MOND if Milgrom's formula is interpreted as Newtonian
gravity with an extra source term instead of as a modification of inertia. We
find that discrepancies between MDM and MOND will occur near the center of a
typical spiral galaxy. In these regions, instead of continuing to rise sharply,
the MDM mass density turns over and drops as we approach the center of the
galaxy. Our results show that MDM, which restricts the nature of the dark
matter quantum by accounting for Milgrom's scaling, accurately reproduces
observed rotation curves.Comment: Preprint number IPMU13-0147. Accepted for publication in Ap
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