A mathematical model was developed to simulate alternative
selection and crossbreeding strategies for commercial beef production.
Biological and economic constraints were selected to represent
typical pasture production of calves in the Northwest. The
crossbreeding study evaluated the relative economic efficiency of
different 1) mating plans when sire breeds of several...
Levels of ⁶⁵Zn in water, sediments, plants, and animals in
Alder Slough, a small ecosystem in the Columbia River Estuary,
were determined periodically during a one year period. Concentrations
of total Zn in organisms were also measured to permit
computation of specific activities (μCi⁶⁵Zn/g total Zn). Temporal
fluctuations in the...
I compare the seasonal abundance variation, population dynamics, fecundity, egg hatching mechanism and success, and apostome ciliate parasites of the euphausiids Euphausia pac?fica and Thysanoessa spinfera from the Oregon coast, USA. Community structure and nearshore distributions were examined from bi-weekly oceanographic surveys (1970-1972). This region has a strong cross-shelf change...