Across western Oregon, Washington, and British Columbia, forest management practices over the past century reduced the amount of late-successional forest while
simultaneously increasing the amount of young (less than 80 years old), managed
Douglas-fir (Pseudotsuga menziesii) dominated forests. Recently, concerns over loss of late-successional habitat pushed management objectives on public...
Biomass burning associated with deforestation and land use in the Amazon, greatly contributes to emissions as well as depletion of elemental pools. We identified deforestation and pasture formation and quantified resultant burning emissions and terrestrial aboveground elemental pool losses during a period of early colonization in the vicinity of Jamari,...
Increased competition brought about by trade liberalization has raised the stakes
for improving productivity in U.S. and Canadian food processing. A key element of
productivity growth is technological change, which in turn results from R&D investment.
The present study employs an econometric model to assess rates of technological change
and...
Plant form is a compromise between resource gathering, reproduction and
the tolerance to physical demands of the abiotic and biotic environment. In
an agricultural field in addition to the natural factors causing stress, humans
also introduce physical and mechanical stresses, and chemical pesticides
into the environment. Many of these factors...
Relative growth and survival of offspring from matings of hatchery and wild Deschutes River (Oregon) summer steelhead trout, Salmo gairdneri, were monitored to determine if hatchery fish differ genetically from wild fish in traits which can affect the stock-recruitment relationship of wild populations. Four natural streams and a hatchery pond...
There is a strong evidence that human papillomavirus (HPV) is the key causative agent of cervical cancer. However, the majority of women who are exposed to the oncogenic HPV do not develop invasive cervical cancer, suggesting that other factors could play a role in the cause and progression of cervical...
The purpose of this study was to compare the effectiveness of
teaching high school health by team teaching and traditional teaching
methods. For this study 114 second-semester sophomore health
students from Centennial High School in Gresham, Oregon were
used, distributed in three health classes as a control group, utilizing
traditional...
Cheletomorpha lepidopterorum (Shaw), a predaceous, prostigmatid
mite, was studied under laboratory conditions of 20° - 30° C
and 80% - 90% R. H. to determine its effectiveness as a possible
biological control agent of Acarus farris (Oud. ), a graminivorous
mite which infests stored grains and grain products. Although
Cheletophyes...