Life Sciences Commons^™

Magnesium Deficiency And Excitability In The Rat: An Examination Of Selected Biochemical And Physiological Events Relating Magnesium Status To Behavior, Douglas Robinson Buck

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of Mg status on the behavior of rats, as determined by nonspecific excitability level and audiogenic seizure susceptibility, was investigated. Also, selected biochemical and neurological mechanisms mediating the chain of events from dietary magnesium deficit to the hyperexcitability symptoms were examined. Weanling rats fed a low magnesium (10 ppm) diet for 14 days had reduced serum, cerebrospinal fluid and brain magnesium concentrations, and increased brain (Na⁺ K⁺) -ATPase activity. They exhibited increased NEL and became highly susceptible to audiogenic seizures. Through dietary manipulation and intraperitoneal and cerebral intraventricular injections, it was possible selectively to alter …

The Social Behavior Of Brown Bears At Mcneil River, Alaska, Allan L. Egbert

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The social behavior of brown bears (Ursus arctos) was studied during the summers of 1972 and 1973 as bears fished for salmon at McNeil River, Alaska. Study objectives were to determine behavioral characteristics of bears in relation to sex and age, changes in social behavior over a 40-day long fishing season, social and environmental parameters correlated with the occurrence of behavior, and to test the hypothesis that brown bears modify social behavior in a feeding aggregation to exploit a resource limited in time and space.

Over one-half of the agonistic interactions consisted of passive deferrals. Encounters that included …