31,586 research outputs found
Luminosity Function of the Perigalactocentric Region
We present H and K photometry of 42,000 stars in an area of 250 arcmin
centered on the Galactic center. We use the photometry to construct a
dereddened K band luminosity function (LF) for this region, excluding the
excessively crowded inner 2' of the Galaxy. This LF is intermediate between the
LF of Baade's window and the LF of inner 2' of the Galactic center. We
speculate that the bright stars in this region have an age which is
intermediate between the starburst population in the Galactic center and the
old bulge population. We present the coordinates and mags for 16 stars with
K_{0} < 5 for spectroscopic follow up.Comment: 25 pages. Tarred, gzipped and uuencoded. Includes LaTex source file,
Figures 3 to 9 and 5 Tables. Figures 1 and 2 are available at
ftp://bessel.mps.ohio-state.edu/pub/vijay . Submitted to Ap
One-pot radioiodination of aryl amines via stable diazonium salts: preparation of 125I-imaging agents
An operationally simple, one-pot, two-step tandem procedure that allows the incorporation of radioactive iodine into aryl amines via stable diazonium salts is described. The mild conditions are tolerant of various functional groups and substitution patterns, allowing late-stage, rapid access to a wide range of 125I-labelled aryl compounds and SPECT radiotracers
Improved quantum algorithms for the ordered search problem via semidefinite programming
One of the most basic computational problems is the task of finding a desired
item in an ordered list of N items. While the best classical algorithm for this
problem uses log_2 N queries to the list, a quantum computer can solve the
problem using a constant factor fewer queries. However, the precise value of
this constant is unknown. By characterizing a class of quantum query algorithms
for ordered search in terms of a semidefinite program, we find new quantum
algorithms for small instances of the ordered search problem. Extending these
algorithms to arbitrarily large instances using recursion, we show that there
is an exact quantum ordered search algorithm using 4 log_{605} N \approx 0.433
log_2 N queries, which improves upon the previously best known exact algorithm.Comment: 8 pages, 4 figure
Carrion Beetles (Coleoptera: Silphidae) of Wisconsin
The first comprehensive faunal survey of the carrion beetles (Coleoptera: Silphidae) of Wisconsin is presented. Six genera and 14 species are recorded from the state, including a new state record, Heterosilpha ramosa (Say). Nicrophorus americanus Olivier was not recovered during this study. An annotated checklist includes species-specific geographical and temporal distributions, remarks on foods and habitat, and counties of specimen collections for each species
Assessment of fish populations and habitat on Oculina Bank, a deep-sea coral marine protected area off eastern Florida
A portion of the Oculina Bank located off eastern Florida is
a marine protected area (MPA) preserved for its dense populations of the ivory tree coral (Oculina varicosa),
which provides important habitat for fish. Surveys of fish assemblages and benthic habitat were conducted inside and outside the MPA in 2003 and 2005 by using remotely operated
vehicle video transects and digital still imagery. Fish species composition, biodiversity, and grouper densities
were used to determine whether O. varicosa forms an essential habitat compared to other structure-forming
habitats and to examine the effectiveness of the MPA. Multivariate analyses indicated no differences in fish
assemblages or biodiversity among hardbottom habitat types and grouper densities were highest among the most complex habitats; however the higher densities were not exclusive to
coral habitat. Therefore, we conclude that O. varicosa was functionally equivalent to other hardbottom habitats. Even though fish assemblages were not different among management
areas, biodiversity and grouper densities were higher inside the MPA compared to outside. The percentage of intact coral was also higher inside the MPA. These results provide initial evidence demonstrating effectiveness of the MPA for restoring reef fish and their habitat. This is the first study to compare reef fish populations on O. varicosa with other structure-forming reef habitats and also the first to examine the effectiveness of the MPA for restoring fish populations and live reef cover
Sulfate Reduction in Sediments Produces High Levels of Chromophoric Dissolved Organic Matter
Sulfate reduction plays an important role in altering dissolved organic matter (DOM) in estuarine and coastal sediments, although its role in the production of optically active chromophoric DOM (CDOM) and a subset of fluorescent DOM (FDOM) has not been previously investigated in detail. Freshwater sediment slurries were incubated anaerobically with added sulfate and acetate to promote sulfate-reducing bacteria. Ultraviolet visible (UV-Vis) absorbance and 3-dimensional excitation emission matrix (EEM) fluorescence spectra were measured over a five weeks anaerobic dark incubation period. Parallel Factor Analysis (PARAFAC) of FDOM determined components that increased significantly during dark and anaerobic incubation matching three components previously considered of terrestrially-derived or humic-like origin published in the OpenFluor database. The observed FDOM increase was strongly correlated (R2 = 0.96) with the reduction of sulfate. These results show a direct experimental link between sulfate reduction and FDOM production, which impacts our understanding of coastal FDOM sources and early sediment diagenesis. As 3D fluorescence techniques are commonly applied to diverse systems, these results provide increasing support that FDOM can have many diverse sources not consistently captured by common classifications such as “humic-like” fluorescence
East Germany in from the Cold: The Economic Aftermath of Currency Union
macroeconomics, East Germany, currency union
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