10,648 research outputs found
Stability of an upwind Petrov Galerkin discretization of convection diffusion equations
We study a numerical method for convection diffusion equations, in the regime
of small viscosity. It can be described as an exponentially fitted conforming
Petrov-Galerkin method. We identify norms for which we have both continuity and
an inf-sup condition, which are uniform in mesh-width and viscosity, up to a
logarithm, as long as the viscosity is smaller than the mesh-width or the
crosswind diffusion is smaller than the streamline diffusion. The analysis
allows for the formation of a boundary layer.Comment: v1: 18 pages. 2 figures. v2: 22 pages. Numerous details added and
completely rewritten final proof. 8 pages appendix with old proo
Financial Stability and Casino Debt
Casino operators have always borrowed money to construct and improve their resorts. Beginning in 1999, however, the Las Vegas-based companies that dominate gambling in Nevada and many other jurisdictions began taking on unprecedented levels of debt. This debt load escalated from 2005 to 2009, and, though it has since leveled off, it has left casino operators more highly leveraged than ever before. Companies with such high levels of debt have consequently high interest payments, which leads to less money available for capital investment; it also makes them susceptible to default, should revenues weaken (as casino revenues did from 2008 onward). When extreme leveraging impacts a casinoâs financial performance and viability as a going concern, it may become a legitimate area of interest for regulators.
Recently, MGM Resorts International announced plans to issue 13.45 billion debt, the new issue will increase MGM Resortsâ indebtedness to nearly 5.8 billion, MGM has a debt/capitalization ratio of approximately 240%.1 Companies this highly leveraged (and with correspondingly high interest costs) are extremely sensitive to fluctuations in cash flow, and the past several years have proven that casino gaming, while it is still an industry with high profit potential, is prone to fluctuations in cash flow due to changes in consumer spending and competition from new jurisdictions. The historic levels of debt that many casino companies have taken on may threaten the future stability of individual companies and the gaming industry as a whole
A Monolithic Time Stretcher for Precision Time Recording
Identifying light mesons which contain only up/down quarks (pions) from those
containing a strange quark (kaons) over the typical meter length scales of a
particle physics detector requires instrumentation capable of measuring flight
times with a resolution on the order of 20ps. In the last few years a large
number of inexpensive, multi-channel Time-to-Digital Converter (TDC) chips have
become available. These devices typically have timing resolution performance in
the hundreds of ps regime. A technique is presented that is a monolithic
version of ``time stretcher'' solution adopted for the Belle Time-Of-Flight
system to address this gap between resolution need and intrinsic multi-hit TDC
performance.Comment: 9 pages, 15 figures, minor corrections made, to appear as JINST_008
Chemically engineering ligand selectivity at the free fatty acid receptor 2 based on pharmacological variation between species orthologs
When it is difficult to develop selective ligands within a family of related G-protein-coupled receptors (GPCRs), chemically engineered receptors activated solely by synthetic ligands (RASSLs) are useful alternatives for probing receptor function. In the present work, we explored whether a RASSL of the free fatty acid receptor 2 (FFA2) could be developed on the basis of pharmacological variation between species orthologs. For this, bovine FFA2 was characterized, revealing distinct ligand selectivity compared with human FFA2. Homology modeling and mutational analysis demonstrated a single mutation in human FFA2 of C4.57G resulted in a human FFA2 receptor with ligand selectivity similar to the bovine receptor. This was exploited to generate human FFA2-RASSL by the addition of a second mutation at a known orthosteric ligand interaction site, H6.55Q. The resulting FFA2-RASSL displayed a >100-fold loss of activity to endogenous ligands, while responding to the distinct ligand sorbic acid with pEC(50) values for inhibition of cAMP, 5.83 ± 0.11; Ca(2+) mobilization, 4.63 ± 0.05; ERK phosphorylation, 5.61 ± 0.06; and dynamic mass redistribution, 5.35 ± 0.06. This FFA2-RASSL will be useful in future studies on this receptor and demonstrates that exploitation of pharmacological variation between species orthologs is a powerful method to generate novel chemically engineered GPCRs
The first high-amplitude delta Scuti star in an eclipsing binary system
We report the discovery of the first high-amplitude delta Scuti star in an
eclipsing binary, which we have designated UNSW-V-500. The system is an
Algol-type semi-detached eclipsing binary of maximum brightness V = 12.52 mag.
A best-fitting solution to the binary light curve and two radial velocity
curves is derived using the Wilson-Devinney code. We identify a late A spectral
type primary component of mass 1.49+/-0.02 M_sun and a late K spectral type
secondary of mass 0.33+/-0.02 M_sun, with an inclination of 86.5+/-1.0 degrees,
and a period of 5.3504751+/-0.0000006 d. A Fourier analysis of the residuals
from this solution is performed using PERIOD04 to investigate the delta Scuti
pulsations. We detect a single pulsation frequency of f_1 = 13.621+/-0.015 c/d,
and it appears this is the first overtone radial mode frequency. This system
provides the first opportunity to measure the dynamical mass for a star of this
variable type; previously, masses have been derived from stellar evolution and
pulsation models.Comment: 7 pages, 6 figures, 2 tables, for submission to MNRAS, v2: paper size
change, small typographical changes to abstrac
Complex network analysis of literary and scientific texts
We present results from our quantitative study of statistical and network
properties of literary and scientific texts written in two languages: English
and Polish. We show that Polish texts are described by the Zipf law with the
scaling exponent smaller than the one for the English language. We also show
that the scientific texts are typically characterized by the rank-frequency
plots with relatively short range of power-law behavior as compared to the
literary texts. We then transform the texts into their word-adjacency network
representations and find another difference between the languages. For the
majority of the literary texts in both languages, the corresponding networks
revealed the scale-free structure, while this was not always the case for the
scientific texts. However, all the network representations of texts were
hierarchical. We do not observe any qualitative and quantitative difference
between the languages. However, if we look at other network statistics like the
clustering coefficient and the average shortest path length, the English texts
occur to possess more clustered structure than do the Polish ones. This result
was attributed to differences in grammar of both languages, which was also
indicated in the Zipf plots. All the texts, however, show network structure
that differs from any of the Watts-Strogatz, the Barabasi-Albert, and the
Erdos-Renyi architectures
Surface Tension at Finite Tempearture in the MIT Bag Model
At the surface tension in the MIT bag model for a
single hadron is known to be negligible as compared to the bag pressure . We show that at finite temperature it has a substantial value of 50 -
70 MeV which also differ from hadron to hadron. We also find that the dynamics
of the Quark-Gluon Plasma is such that the creation of hybrids
with massive quarks will predominate over the creation of
mesons.Comment: Substantial changes in the revised version and a new author included,
13 pages in Latex and one figur
The UNSW Extrasolar Planet Search: Methods and First Results from a Field Centred on NGC 6633
We report on the current status of the University of New South Wales
Extrasolar Planet Search project, giving details of the methods we use to
obtain millimagnitude precision photometry using the 0.5m Automated Patrol
Telescope. We use a novel observing technique to optimally broaden the PSF and
thus largely eliminate photometric noise due to intra-pixel sensitivity
variations on the CCD. We have observed 8 crowded Galactic fields using this
technique during 2003 and 2004. Our analysis of the first of these fields
(centred on the open cluster NGC 6633) has yielded 49 variable stars and 4
shallow transit candidates. Follow-up observations of these candidates have
identified them as eclipsing binary systems. We use a detailed simulation of
our observations to estimate our sensitivity to short-period planets, and to
select a new observing strategy to maximise the number of planets detected.Comment: 16 pages, 9 figures, version published in MNRAS Updated figures,
references, and additional discussion in section
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