Effects of Anthropogenic Light and Noise on Anuran Breeding Behavior

The natural environment can be negatively impacted by a variety of human activities, including the production of artificial light at night and anthropogenic noise. Recent studies suggest that pollution from anthropogenic light and noise alters animal behavior. Despite being highly nocturnal and vocal animals, little attention has been given to anurans and the effects artificial light at night and anthropogenic noise have on their behavior. This study investigated the effects of artificial light at night and anthropogenic noise on anuran breeding systems in eastern Texas. Specifically, this study investigated whether (1) artificial light and anthropogenic noise altered calling behavior in male anurans, (2) artificial light influenced male call site selection, and (3) artificial light influenced female mate choice. Ambient light and sound levels were quantified at five sites that varied in urbanization and, therefore, artificial light and anthropogenic noise levels. At these sites, calling males were recorded and ambient light was then measured at the male’s call site. Call parameters including call dominant frequency, call duration, pulse rate, and call rate were analyzed for differences among urban and rural populations. Call site light microhabitat measurements were compared to the general light environment as well as among populations. Additionally, females were tested in two phonotaxis experiments to determine their mate choice preferences under dark and elevated light conditions. Effects of artificial light and anthropogenic noise varied among species. All species studied exhibited alterations in either call dominant frequency, call duration, or call rate. At urban sites, most anuran species called from sites almost significantly or significantly darker than the general light environment. While most anurans preferred call sites darker than the surrounding environment, urban anuran populations had brighter call sites than rural anuran populations. In female mate choice experiments, female Green Treefrogs (Hyla cinerea) from a rural population preferred lower frequency calls under elevated light conditions. These results suggest anuran species may vary in their sensitivity and response to artificial light at night and anthropogenic noise

Preparation, testing and analysis of zinc diffusion samples, NASA Skylab experiment M-558

Transport mechanisms of zinc atoms in molten zinc were investigated by radiotracer techniques in unit and in near-zero gravity environments. Each melt in the Skylab flight experiments was maintained in a thermal gradient of 420 C to 790 C. Similar tests were performed in a unit gravity environment for comparison. After melting in the gradient furnace followed by a thermal soak period (the latter was used for flight samples only), the samples were cooled and analyzed for Zn-65 distribution. All samples melted in a unit gravity environment were found to have uniform Zn-65 distribution - no concentration gradient was observed even when the sample was brought rapidly to melting and then quenched. Space-melted samples, however, showed textbook distributions, obviously the result of diffusion. It was evident that convection phenomena were the dominant factors influencing zinc transport in unit gravity experiments, while diffusion was the dominant factor in near-zero gravity experiments

Target preparations and thickness measurements

A wide variety of isotope target preparative methods have been used, including rolling of metals, vapor deposition, electrodeposition, chemical vapor deposition, and sputtering, to obtain thin and thick films of most elements or compounds of elements in the Periodic Table. Most thin films prepared for use in self-supported form as well as those deposited on substrates require thickness measurement (atom count and distribution) and/or thickness uniformity determination before being used in nuclear research. Preparative methods are described together with thickness and uniformity determination procedures applicable to samples being prepared (in situ) and to completed samples. Only nondestructive methods are considered applicable to target samples prepared by the ORNL Solid State Division, Isotope Research Materials Laboratory. Thickness or areal density measurements of sufficient sophistication to yield errors of less than +-1 percent have been achieved with regularity. A statistical analysis procedure is applied which avoids error caused by balance zero-point drift in direct weight measurement methods. (auth

Development of cermets for high level radioactive waste fixation

A method for the solidification and fixation of commercial and defense high-level radioactive wastes, namely a cermet process, is currently under development. Chemical and physical processing techniques, as developed up to this time, and the subsequent properties of the resulting cermet bodies are described; unique and advantageous features of the cermet waste form and the conversion process are discussed

Separation of tritium from gaseous and aqueous effluent systems

Three processes are discussed for separating tritium from gaseous and aqueous effluent systems: separation in the gas phase using Pd-25 wt percent Ag alloy diffusion membranes; electrolytic separation in the aqueous phase using ''bipolar'' electrodes; and the countercurrent exchange of tritium-containing hydrogen gas with water on catalytic surfaces combined with separation by direct electrolysis. (LK