We investigate the optimal harvesting strategies for McKendrick type population models. Models of this type endow the population with a continuous age structure. They consist of a partial differential equation with a boundary condition which involves an integral of the solution. We study two problems, the first concerns the yield...
We are at risk of losing the sagebrush steppe in the floristic Great Basin to the invasion of Bromus tectorum L., cheatgrass. The floristic Great Basin includes the Central Basin and Range, the Northern Basin and Range, and the Snake River Plain. The Great Basin receives most of its precipitation...
The research involved development of two ecological
simulation models to explain the complex dimensionality of
chinook salmon (Oncorhynchus tshawytscha) life history
structure (represented by the age composition of the
spawning stock) and management difficulties entailed in the
complexity.
Since different sizes of chinook salmon are thought to
adapt differently to...
Development of a performance analysis for propeller type wind
turbines is presented. The analysis uses a strip theory approach
that includes tip-loss and blade interference. A comparison is
presented between analysis and test data. The comparison indicates
that the analysis predicts wind turbine performance to an accuracy
that is within...
The hypotheses of this study stated the following:
Interaction with the computer game will significantly
increase the class means in: (1) mathematical
achievement, (2) attitudes toward mathematics, and (3)
graphing ability in high school advanced algebra.
ALGEBRA ARCADE is a computerized simulation game
played on a coordinate grid. One can...
The purpose of this study was to compare the Chapter I supplemental mathematics program CAI with other Chapter I supplemental mathematics programs, Prescription Learning and the traditional "pull-out" program, in terms of achievement and retention of mathematics basic skills. There were 577 Chapter I students from 12 middle schools and...
Accurate taxonomy is essential to preservation and management of native
grasses. Four problems in fescue taxonomy were investigated: the identity of the
native fescue that dominates western Oregon and Washington prairies, the relationship
of native Festuca roemeri to closely related grasses, the status of F. howellii and F.
washingtonica, and...