3,125 research outputs found
Superstring Theory on pp Waves with ADE Geometries
We study the BMN correspondence between certain Penrose limits of type IIB
superstrings on pp-wave orbifolds with geometries, and the set of
four-dimensional superconformal field theories constructed as
quiver gauge models classified by finite Lie algebras and affine
Kac-Moody algebras. These models have 16 preserved supercharges and
are based on systems of D3-branes and wrapped D5- and D7-branes. We derive
explicitly the metrics of these pp-wave orbifolds and show that the BMN
extension requires, in addition to D5-D5 open strings in bi-fundamental
representations, D5-D7 open strings involving orientifolds with gauge
symmetry. We also give the correspondence rule between leading string states
and gauge-invariant operators in the quiver gauge models.Comment: 62 page
A Trend Analysis of Aerosol Related Parameters and their Relation to Precipitation Variability in Arizona
The Objective of our research was to investigate if there is a correlation between haboob outbreaks, resulting in large dust storms over Arizona, and the precipitation patterns over the region. We examined the extent of this correlation over the last ten years using satellite daily observations to highlight the possibility of better forecasts for precipitation events, such as monsoon thunderstorms. Our research indicates that haboobs increase precipitation in the Sonoran desert of Arizona because the dust particles are large enough to act as cloud condensation nuclei (CCN). Data was collected from five locations spread out over the state of Arizona for the years of 2002-2012. The method we utilized was data oriented and required a quantitative analytical approach, where aerosol optical depth (AOD) data from NASA\u27s Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite was collected and analyzed. Rainfall data from NASA\u27s Tropical Rainfall Measuring Mission (TRMM) satellite was collected and analyzed in coherence with the aerosol data. By manipulating this data into a time-series form, we determined the direct correlation between dust and precipitation events. It was found that increased dusty events increased precipitation with an average of two months lag time. Each of the five locations indicated that a strong correlation does exist between the AOD, Angstrom exponent, and precipitation data, indicating that the there are complex interactions occurring between dust and precipitation in Arizona at a microphysical level
Non-commutative ADE geometries as holomorphic wave equations
Borrowing ideas from the relation between classical and quantum mechanics, we
study a non-commutative elevation of the ADE geometries involved in building
Calabi-Yau manifolds. We derive the corresponding geometric hamiltonians and
the holomorphic wave equations representing these non-commutative geometries.
The spectrum of the holomorphic waves is interpreted as the quantum moduli
space. Quantum A_1 geometry is analyzed in some details and is found to be
linked to the Whittaker differential equation.Comment: 17 pages, v2: version to be publishe
Projection of primary and revision hip arthroplasty surgery in Denmark from 2020 to 2050
BACKGROUND AND PURPOSE: The incidence of primary and revision total hip arthroplasty (THA) has increased over the last decades. Previous forecasts from different healthcare systems have predicted a continuous increase. We present a forecast of both primary and revision surgery from 2020 to 2050 based on 25 years data from the healthcare system in Denmark. PATIENTS AND METHODS: We retrieved data from the Danish Hip Arthroplasty Register on 198,835 primary and 29,456 revision surgeries. Historical censuses and population forecasts were retrieved from Statistics Denmark. Logistic and Gompertz regression analysis was used to forecast incidence rates (IR) and total numbers in the next 30 years. RESULTS: Our forecast predicts an increase in IR of 3–9% and an increase in total numbers of primary THA of between 12% and 19% in 2050. For revision THA the IRs have reached a plateau but total numbers are predicted to increase by 19% in 2050. CONCLUSION: Our forecast shows that both primary and revision THA will increase in total numbers in the next decades, but the IR for primary THA is near its plateau and for revision THA the plateau has already been reached. The forecast may aid in healthcare resource planning for the decades to come
Observation of the Magneto-Optic Voigt Effect in a Paramagnetic Diamond Membrane
The magneto-optic Voigt effect is observed in a synthetic diamond membrane
with a substitutional nitrogen defect concentration in the order of 200 ppm and
a nitrogen-vacancy defect sub-ensemble generated through neutron irradiation
and annealing. The measured polarisation rotation in the reflected light is
observed to be quadratically proportional to the applied magnetic field and to
the incident reflection angle. Additionally, it is observed to be modifiable by
illuminating the diamond with a 532 nm laser. Spectral analysis of the
reflected light under 532 nm illumination shows a slow narrowing of the
spectral distribution, indicating a small increase in the overall
magnetisation, as opposed to magnetisation degradation caused by heating.
Further analysis of the optical power dependence suggest this may be related to
a shift in the spin ensembles charge state equilibrium and, by extension, the
resulting ensemble magnetisation.Comment: 6 pages, 5 figure
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