The stability of a third-order, nonlinear system with a
saturation characteristic was studied by applying the second method
of Liapunov, which is the most general approach currently used for
dynamic systems.
This thesis presents (1) the analysis of a third-order, nonlinear
system, (2) a suitable Liapunov function, generated by the...
Bdellovibrio bacteriovorus is a small parasitic bacterium present
in soil, mud, and aquatic habitats. Due to its lysis of Gramnegative
bacteria, an important role in soil ecology has been suggested
for this organism. A study of effects of herbicides upon
Bdellovibrio might consequently be of considerable value.
In this study...
Three coleopterous predators associated with the Douglas-fir
beetle (Dendroctonus pseudotsugae Hopkins in a second growth
forest of Douglas-fir (Pseudotsugae menziesii (Mirb. ) Franco)
in western Oregon are Enoclerus sphegeus Fabriciup, E, lecontei
Wolcott, and Thanasirnus undatulus Say. A study was undertaken
with the following objectives: (1) to determine the diurnal...
Behavioral responses exhibited by the Douglas-fir beetle,
Dendroctonus pseudotsugae Hopkins, to various attractant sources
were investigated under both laboratory and field conditions. Tests
were designed to observe olfactory responses. Results were correlated
and compared with collections from sampling nets and with
emergence patterns. Field data were collected during the flight...
The study was undertaken to determine the seasonal and diurnal
flight patterns of scolytid beetles inhabiting a second growth
forest of Douglas-fir (Pseudotsuga menziesii (Mirb.)Franco) in western
Oregon. Air temperatures, relative humidity, light intensity, and wind
velocities were recorded for evaluation of their influence on flight activity.
The insects were...
Sheep and cattle dietary preferences were determined on tall fescue-subclover ( Festuca arundinacea-Trifolium subterraneum) and
perennial ryegrass-subclover (Lolium perenne-Trifoliuni subterraneum)
pastures in western Oregon during the spring and summer periods
of 1964 and 1965. Esophageal-fistulated Willamette ewes and
Hereford and Hereford-Angus yearling cattle were grazed separately
on each pasture mixture...