A recently developed portable instrument, the pulsed cavity ring-down transmissometer/nephelometer tandem (CRDT/N) allows for the in situ measurement of optical properties of aerosols. An Nd:YAG laser excited CRDT (λ = 532, 1064 nm) is shown to be capable of sensitively measuring the aerosol extinction coefficient (bext) at the two wavelengths simultaneously. Adding a nephelometer yields a meas...

We extend our earlier work on the role of deleterious mutations in the extinction of obligately asexual populations. First, we develop analytical models for mutation accumulation that obviate the need for time-consuming computer simulations in certain ranges of the parameter space. When the number of mutations entering the population each generation is fairly high, the number of mutations per i...

High redshift supernova magnitudes of current interest are reexamined. The magnitudes conventionally reported include an additive parameter called the extinction coefficient. We find that the extinction coefficients of a popular “gold” set are well correlated with the deviation of magnitudes from standard Hubble diagrams. The statistical significance of the extinction-acceleration correlation h...

Multiwavelength Raman/high spectral resolution lidars that measure backscatter coefficients at 355, 532, and 1064 nm and extinction coefficients at 355 and 532 nm can be used for the retrieval of particle microphysical parameters, such as effective and mean radius, number, surface-area and volume concentrations, and complex refractive index, from inversion algorithms. In this study, we carry ou...

A host-parasite model is proposed that incorporates a nonlinear incidence rate. Under the influence of multiple infectious attacks, the model admits bistable regions such that the infection dies out if initial states lie in one region, and the population and parasites coexist if initial states lie in the other region. It is also found that parasites can drive the population to extinction for su...

the aim of this research was to compare more and less competitiveness of rice cultivars against barnyardgrass for light extinction coefficient and canopy structur. a filed experiment was conducted in 2007 growing season in tonekabon’s rice research station in mazandaran province. the experiment layout was a factorial design with four randomized complete blocks. seven rice cultivars (khazar, sep...

Drop size and drop spatial distribution determine photon-cloud interaction. The classical approach assumes that the number of drops of a given radius is proportional to volume with a drop-size-dependent coefficient of proportionality, the drop concentration, which is a volume-independent function of the spatial point. This assumption underlies the derivation of the drop size density distributio...

Films consisting of amorphous carbon dispersed in tetragonal nanocrystalline zirconia were characterized for their optical properties by reflectance measurements. The optical constants of each component of the composite have been extracted; the experimental reflectance spectra have been fitted to Maxwell-Garnett effective medium theory, leading to the effective dielectric constants of the film....