27,410 research outputs found
Enhanced Spontaneous Emission Into The Mode Of A Cavity QED System
We study the light generated by spontaneous emission into a mode of a cavity
QED system under weak excitation of the orthogonally polarized mode. Operating
in the intermediate regime of cavity QED with comparable coherent and
decoherent coupling constants, we find an enhancement of the emission into the
undriven cavity mode by more than a factor of 18.5 over that expected by the
solid angle subtended by the mode. A model that incorporates three atomic
levels and two polarization modes quantitatively explains the observations.Comment: 9 pages, 2 figures, to appear in May 2007 Optics Letter
Algal Assemblage Distribution as Related to Seasonal Fluctuations of Selected Metal Concentrations
Seasonal variations of phytoplankton assemblages have been observed in a mildly eutrophic lake in northwestern Arkansas for six years. The data indicated that certain metal concentrations also varied seasonally. Sodium, potassium, calcium and magnesium ion concentrations, and phytoplankton composition and abundances were examined spatially and temporally. Four major algal blooms characterized the lake: a spring, a summer and an autumnal cyanophycean assemblage and a winter diatom-chrysophyte dominated population. Each metal concentration was inversely proportional to the abundance of the cyanophytes. The presence of the winter assemblage was accompanied by decreases in sodium, calcium and magnesium and increased levels of potassium. First and second order linear regression models were developed for each assemblage
A Computer Program for Population Analysis
A computer program for population analysis has been developed that is simply written, but relatively sophisticated. It consists of three parts: computation and tabulation of data, statistical analysis and plotting. The program can be understood readily by computation center personnel and requires a minimum of modification for use in most facilities. Once the program is instituted, an instructor need only have knowledge of the format requirements to use it. Lack of a programming background need not prevent an instructor from using the computer for population analysis
Profits and balance sheet developments at U.S. commercial banks in 2008
Bank profits ; Banks and banking
COLONIZATION OF NORTHERN LOUISIANA BY THE MEDITERRANEAN GECKO, HEMIDACTYLUS TURCICUS
The Mediterranean Gecko, Hemidactylus turcicus, is known to have colonized nearly every state in the southern United States. In Louisiana, the Mediterranean Gecko has been documented in many of the southern parishes, but records for the northern portion of the state are limited. We sampled northern Louisiana parishes to document the presence of the Mediterranean Gecko. We sampled a total of 21 parishes in northern Louisiana and found geckos in 17 of those parishes, 16 of which represent new distribution records for the species. This indicates a significant range expansion of this introduced species throughout northern Louisiana. Geckos were found across a temperature range of 14.0–28.0°C and had a strong association with buildings. The species’ affinity for anthropogenic association and the continual nature of anthropogenic expansion facilitate the high vagility of this species. The result is a successful colonization throughout much of Louisiana and likely continued range expansion throughout the southern United States
Comparison of inlet suppressor data with approximate theory based on cutoff ratio
Inlet suppressor far-field directivity suppression was quantitatively compared with that predicted using an approximate linear design and evaluation method based upon mode cutoff ratio. The experimental data was obtained using a series of cylindrical point-reacting inlet liners on a YF102 engine. The theoretical prediction program is based upon simplified sound propagation concepts derived from exact calculations. These indicate that all of the controlling phenomenon can be approximately correlated with mode cutoff ratio which itself is intimately related to the angles of propagation within the duct. The theory-data comparisons are intended to point out possible deficiencies in the approximate theory which may be corrected. After all theoretical refinements are made, then empirical corrections can be applied
Introduction to papers on astrostatistics
We are pleased to present a Special Section on Statistics and Astronomy in
this issue of the The Annals of Applied Statistics. Astronomy is an
observational rather than experimental science; as a result, astronomical data
sets both small and large present particularly challenging problems to analysts
who must make the best of whatever the sky offers their instruments. The
resulting statistical problems have enormous diversity. In one problem, one may
have to carefully quantify uncertainty in a hard-won, sparse data set; in
another, the sheer volume of data may forbid a formally optimal analysis,
requiring judicious balancing of model sophistication, approximations, and
clever algorithms. Often the data bear a complex relationship to the underlying
phenomenon producing them, much in the manner of inverse problems.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS234 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
- …