Per- and polyfluoroalkyl substances (PFASs) have emerged in the last half century as concerning global contaminants. PFASs have been found in drinking water systems causing negative health impacts for those who rely on this as their primary source of drinking water. PFASs are man-made industrial chemicals composed of carbon chains...
The effects of natural preconditioning (source wood), wood species, and previous
exposure of wood to two types of fungi on the feeding rates and protozoa survival in the
Pacific dampwood termite Zootermopsis angusticollis (Isoptera: Termospidae) were
examined under laboratory conditions. Termites were exposed to four wood species that
had been...
Phytophthora vignae, causal agent of stem and root
rot of cowpea (Vigna unguiculata), was reported for the
first time in Sri Lanka. The pathogen was found in cowpea
field soils from 3 of 5 geographic regions sampled. Only
one site however, had plants exhibiting disease symptoms.
Of the eight cowpea...
The effect of defoliation intensity and season on Douglas-fir growth
were studied in three replications in the Siuslaw National Forest during
1988-1990. Four intensities of defoliation were applied once in either spring or
summer 1988. Stem diameter and canopy area were linearly inversely
proportional to the level of defoliation. Defoliation...
Sex differentiation in fish is a labile process that allows sex inversion in several species. The inherent capacity of fish germ cells to differentiate into oocytes or spermatocytes constitutes a key factor allowing for functional sex inversion. This thesis set out to determine the mechanism involved in steroid-induced sex differentiation...
The effects of forest cutting on forested systems and the biotic components of those systems has been at the forefront of scientific research. The inventory and monitoring of biodiversity is one technique used for measuring the effects of forest management. Because bioinventory studies are expensive, indicator species are often sought...
This study was directed to improve our understanding of the ecology of Swiss needle cast (SNC) of Douglas-fir, a disease that produces extensive damage to forests and plantation in the coastal region of Oregon and Washington. A disease prediction model for the coastal area of Oregon was built by establishing...
This dissertation investigates the problem of uncertainty in complex ecological models. The term "complex" is used to convey both the common and scientific meanings. Increasingly, ecological models have become complex because they are more complicated; ecological models are generally multi-variate and multi-leveled in structure. Many ecological models are complex because...