A new optical recording medium

Method has been developed for doping lithium niobiate crystals with transition metal to increase rate at which crystal can record optical data. Discovery may facilitate development of system for analog storage of TV frames, printed pages, photographs, and other visual information

A Variational Principle for the Asymptotic Speed of Fronts of the Density Dependent Diffusion--Reaction Equation

We show that the minimal speed for the existence of monotonic fronts of the equation $u_t = (u^m)_{xx} + f(u)$ with $f(0) = f(1) = 0$, $m >1$ and $f>0$ in $(0,1)$ derives from a variational principle. The variational principle allows to calculate, in principle, the exact speed for arbitrary $f$. The case $m=1$ when $f'(0)=0$ is included as an extension of the results.Comment: Latex, postcript figure availabl

Observations of Late Fall Migratory Sandhill Cranes, Platte River, Nebraska

Observations of migratory Sandhill Cranes (Grus canadensis) were made on the Platte River near Kearney, Nebraska. On 26 November 1978, night roosting in the Platte River occurred on thin ice (less than 2 cm) in open areas which were protected by riparian vegetation from cold north winds (35-40 km/hr-NNW, -10°C). Roosting Cranes were spaced very closely (less than 0.5 m) during evening and early morning hours, with increased spacing (about 1.0 m) occurring during late morning. A diagram of the roost area was prepared. The roost was located near the northern river bank in a river stretch characterized by low, herbaceous type sandbar islands (vegetation about 1 m or less in height). No roosting occurred on islands, but some Cranes at the periphery of the flock roosted in the lower one-half of the northern river bank, which supported vegetation from 1.2 to 2.4 m tall, primarily sparsely spaced willow trees and sunflowers

Observations of Late Fall Migratory Sandhill Cranes, Platte River, Nebraska

Observations of migratory Sandhill Cranes (Grus canadensis) were made on the Platte River near Kearney, Nebraska. On 26 November 1978, night roosting in the Platte River occurred on thin ice (less than 2 cm) in open areas which were protected by riparian vegetation from cold north winds (35-40 km/hr-NNW, -10°C). Roosting Cranes were spaced very closely (less than 0.5 m) during evening and early morning hours, with increased spacing (about 1.0 m) occurring during late morning. A diagram of the roost area was prepared. The roost was located near the northern river bank in a river stretch characterized by low, herbaceous type sandbar islands (vegetation about 1 m or less in height). No roosting occurred on islands, but some Cranes at the periphery of the flock roosted in the lower one-half of the northern river bank, which supported vegetation from 1.2 to 2.4 m tall, primarily sparsely spaced willow trees and sunflowers

Development of a theory of the spectral reflectance of minerals, part 4

A theory of the spectral reflectance or emittance of particulate minerals was developed. The theory is expected to prove invaluable in the interpretation of the remote infrared spectra of planetary surfaces