43,857 research outputs found
Generalized Miller Formulae
We derive the spectral dependence of the non-linear susceptibility of any
order, generalizing the common form of Sellmeier equations. This dependence is
fully defined by the knowledge of the linear dispersion of the medium. This
finding generalizes the Miller formula to any order of non-linearity. In the
frequency-degenerate case, it yields the spectral dependence of non-linear
refractive indices of arbitrary order.Comment: 12 pages, 1 figure (4 panels
Role of spatial coherence in polarization tomography
We analyze an experimental setup in which a quasi-monochromatic spatially
coherent beam of light is used to probe a paraxial optical scatterer. We
discuss the effect of the spatial coherence of the probe beam on the Mueller
matrix representing the scatterer. We show that according to the degree of
spatial coherence of the beam, the \emph{same} scattering system can be
represented by \emph{different} Mueller matrices. This result should serve as a
warning for experimentalists.Comment: 3 pages, 1 figur
Identification of type A and B isolates of Epstein-Barr virus by polymerase chain reaction
A method is described for the identification of type A and type B isolates of Epstein-Barr virus (EBV) by means of the polymerase chain reaction. The use of three pairs of primers specific for genomic sequences coding for the two forms of EBV nuclear antigen (EBNA), 2A and 2B, and for a DNA sequence from the BamZ/BamR region allows the reliable and rapid detection of type A and B viruses in as little as 1000 EBV positive cells
Estimating Potential Ground and Surface Water Pollution from Land Application of Poultry Litter - II
In Arkansas, approximately 1 Tg of poultry (Gallus gallus domesticus) manure and litter is produced annually. These waste products are commonly applied to pastures as a soil amendment or fertilizer, but excessive application rates and poor management practices could result in nutrient contamination of ground and surface water. The purpose of this study was to: (1) assess the nutrient concentrations in poultry manure and (2) evaluate the nitrogen loss from land-applied poultry litter and manure due to ammonia volatilization and denitrification. Analyses for total Kjeldahl nitrogen (TKN), inorganic nitrogen (Ni), phosphorus (P), and potassium (K) were compared in 12 wet and dry hen manure samples. Drying the manure reduced the TKN from 57 to 40 g N/kg on a dry weight basis in wet and dry manure, respectively. The Ni in the manure was in the ammoniacal form with values of 19 and 2 g N/kg for wet and dry manure, respectively. The P and K levels were not influenced by drying the manure and had values of 24 and 21 g/kg, respectively. The results indicate that the nitrogen content of hen manure can be significantly reduced by drying the sample prior to analysis. In a 10-day laboratory study and an 11-day field study to evaluate ammonia volatilization from surface-applied hen manure, results indicated that 37% of the total nitrogen content of the manure was lost. The results indicated that a substantial amount of nitrogen in surface-applied poultry waste can be lost due to ammonia volatilization. Laboratory studies to evaluate denitrification in a Captina silt loam amended with 9 Mg/ha of poultry litter were conducted. When the soil was aerobically incubated for 168 h and then flooded for 66 h, the nitrate-nitrogen level decreased a net of 17 mg N/kg. The results indicated that, if the ammoniacal nitrogen in the litter is oxidized to nitrate under aerobic conditions and then the soil is flooded and available carbon is present, denitrification can occur rapidly. Results from these studies indicate that soil and environmental conditions playa critical role in determining the potential for nitrate pollution of ground and surface water when poultry manure and litter are surface-applied to pastures
Apsidal motion and light a curve solution for eighteen SMC eccentric eclipsing binaries
Aims: The Danish 1.54-meter telescope at the La Silla observatory was used
for photometric monitoring of selected eccentric eclipsing binaries located in
the Small Magellanic Cloud. The new times of minima were derived for these
systems, which are needed for accurate determination of the apsidal motion.
Moreover, many new times of minima were derived from the photometric databases
OGLE and MACHO. Eighteen early-type eccentric-orbit eclipsing binaries were
studied.
Methods: Their (O-C) diagrams of minima timings were analysed and the
parameters of the apsidal motion were obtained. The light curves of these
eighteen binaries were analysed using the program PHOEBE, giving the light
curve parameters. For several systems the additional third light also was
detected.
Results: We derived for the first time and significantly improved the
relatively short periods of apsidal motion from 19 to 142 years for these
systems. The relativistic effects are weak, up to 10% of the total apsidal
motion rate. For one system (OGLE-SMC-ECL-0888), the third-body hypothesis was
also presented, which agrees with high value of the third light for this system
detected during the light curve solution.Comment: 8 pages, 5 figures, 4 tables, plus the appendix data tables with
times of minima. Published in 2014A&A...572A..71
- …