The influence of the physical environment on organisms has long been a subject of ecological research. But, the complex drivers of environmental variation, and the multiple scales at which this can occur, make studying this topic a difficult challenge. In rocky intertidal habitats, oceanographic- and climate-scale variability influence benthic communities...
Response to heterosis for plant height, anthesis date, panicle
number, seed yield, and fall vigor rating was determined in a tall.
fescue group selected for diverse morphology, origin, and anthesis
date. Parents, single-cross progeny (SX), and first generation
selfed progeny (S₁) were included in the study.
Each experimental plot consisted...
An experiment was conducted to examine the responses to
selection for high and low rate of gain in the mouse under a system
whereby inbreeding was maximized. Rate of gain was measured by an
index designed to include gains in both the pre- and postweaning
periods with the gains in...
A population of the Douglas-fir cone moth, Barbara colfaxiana
(Kft. ), was studied on the Buckhead Seed Production Area, Oakridge,
Oregon, during 1971 and 1972. A method of estimating cone and
insect populations is presented. Factors contributing to the mortality
of B. colfaxiana are discussed, with resinosis being the critical...
Observations were made on silage pH, chemical composition and 24hr in vitro dry matter digestion (IVDMD) to evaluate effects of various additives ensiled with annual ryegrass straw. Additives were compared in factorial designed trials utilizing .95 1 glass jar silos. Selection of additives used in each subsequent trial was based...
The metabolism of pyrrolizidine alkaloids and other
drugs was studied with regard to nutritional status and
species differences. Pyrrolizidine alkaloids which are biotransformed
to severely toxic metabolites were isolated
from tansy ragwort (Senecio jacobaea). Semi-purified alkaloid
crystals containing five alkaloids (senecionine, seneciophylline,
jacobine, jacoline, and jacozine) were prepared
and found...
A simulation model capable of execution on a programmable
calculator was developed to study voluntary intake,
liveweight change, and fertility of grade Zebu cows in the
Llanos of Colombia. Organic nitrogen in the diet and meta
bolic weight were used to predict intake; age, liveweight,
and energy concentration were the...
The focus of this study was to determine if S₁ family recurrent
selection might be successfully used for barley improvement.
Objectives were: 1) to identify suitable methods of evaluating grain
yield in small plots, 2) to study the effects of intermating on mean
values and variances of selected agronomic characters,...
This study was conducted to investigate the involvement of selenium and glutathione peroxidase in
prostaglandin biosynthesis by the ram vesicular gland.
Vesicular glands were collected from healthy intact
rams covering a wide range of selenium nutrition and were
analyzed for selenium concentrations, glutathione
peroxidase activities and levels of prostaglandin E₂...
Several experiments were conducted to examine the toxicity of Senecio jacobaea (SJ) in animals resistant to pyrrolizidine alkaloid (PA) intoxication and to determine the extent of alterations in mineral metabolism as a result of SJ intoxication. Inclusion of SJ into diets containing added copper (Cu) resulted in increased (P<.01) liver...
In an effort to describe the plant communities and
succession of the Oregon coastal grasslands, vegetation
and environmental data were collected from 75 stands at
24 separate locations ranging from Cape Falcon in Tillamook
County to Cape Ferrelo in Curry County. The vegetation
data consisted of cover and frequency values...
The western Nearctic species of the genus Phytocoris Fallen were
taxonomically revised. Over 15,000 specimens were examined.
Information concerning host plant associations and distributions was
compiled and summarized for use by future researchers. External
morphological features and characters of the male genitalia were used
to distinguish species. The genital tubercles...
Responses to two cycles of mass selection for heading date,
followed by selfing or intermating, were studied in two diverse
winter wheat (Triticum aestivum L. em. Thell) crosses. Selection
was bidirectional, resulting in early and late populations for
each mating system, cycle, and cross. The influence of mass
selection for...
A vegetation study was made of four coastal marshes near Juneau,
Alaska. Results confirmed earlier studies' findings in southeast
Alaska that communities or assemblages of species can be identified
but from marsh to marsh these assemblages appear to have no consistent
relationship to each other or to environmental "factors" such...
Developmental thresholds and thermal unit (degree
day) requirements for eggs, different larval instars,
pupal stage and preoviposition period were determined
for the obliquebanded leafroller (OBLR), Choristoneura
rosaceana (Harris). Separate thresholds and degree day
requirements were determined for males and females, but
differences between the sexes were not significant.
However, there...
Two management systems were evaluated in terms of the effects on
cow condition score and body weight changes and calf growth rates. The
management systems evaluated were winter supplementation of energy,
winter creep feeding and delayed weaning. The calves used in this study
were born in September and October of...
After three decades of active research coupling hydrology and stream ecology, the connection among solute transport, metabolism and processing is still unresolved. These knowledge gaps obscure the functioning of stream ecosystems and how those ecosystems interact with other landscape processes. We must resolve these challenges to wisely manage water resources,...
A study of the phyletic relationships among five species of
tragopans and an outgroup, the Blood Pheasant (Ithaginis cruentus), was
conducted from 1987 to 1991. Biochemical, behavioral, and external
morphologic characteristics were compared. A cladistic approach was
used to compare the behavioral, biochemical, and external morphologic
data collectively, as different...
A technique is developed and tested to analyze the interaction of flowing water,
bed topography, and bedload sediment transport in meandering channels where gravel
bars are removed. The method relates the local velocity distribution, bed shear stress and
sediment transport conditions to the local bed configuration in river bends before...
It is well known that the mitochondrial genome has a much higher spontaneous mutation rate than the nuclear genome. mtDNA mutations have been identified in association with many diseases and aging. mtDNA replication continues throughout the cell cycle, even in post-mitotic cells. Therefore, a constant supply of nucleotides is required...
The objectives were to investigate the ability of a two-factor
central composite rotatable design (CCRD), using cooking temperature
(CT) and endpoint temperature (ET) as independent variables, to
predict selected chemical, physical and sensory meat quality
characteristics considered important by the industry, researcher and
consumer alike. Response surface analysis (RSA) was...
The effects of mold level (Botrytis cinerea), processing method (fresh, individually quick frozen (IQF), frozen sugared sliced (FSS), freeze dried (FD), canned, and preserves), and maturity (underripe, normal, and overripe) and strawberry volatiles were analyzed by gas liquid chromatography (GLC) using on-column entrainment of headspace volatiles in aqueous extracts. Computerized...
Species interactions and their effect on the use of habitat by benthic fishes were examined in a guild composed of Cottus perplexus, C. rhotheus, and C. beldingi in the Marys River above Philomath, Oregon, and in a constant environment provided by an artificial stream. In the Marys River system, the...
This research details laboratory assessment of bacterial hydrophobicity, variations in bacterial adhesion properties with growth and extended starvation as well as extension of this assay to colloidal hydrophobicity measurement. Hydrophobicity is an integral component of surface interactions and has been studied extensively for its role in a number of engineering...
Verticicladiella wageneri Kendrick is a vascular wilt
pathogen of conifers, causing a black staining of
colonized sapwood of roots and lower stem. In Douglas-fir,
V. wageneri is intimately associated with insects.
Hylastes nigrinus, Pissodes fasciatus, and Steremnuis
carinatus are commonly associated with diseased hosts,
carry inoculum of V. wageneri in...
Growth phenology (i.e., timing of growth initiation and cessation) is important to adaptation. This study examined the extent of genetic control of bud and cambial phenology and their relationships with stem
growth in pole-size Douglas-fir (ages 13 to 16 years) from 60 open-pollinated families. The availability of bud phenology data...
Belowground carbon (C) storage and quality of soil organic matter (SOM) in
forest soils have implications for sustainable forest management and C sequestration,
but how these pools change in response to management is poorly understood. I
investigated whether fertilization and competing vegetation control, applied alone or
in combination early in...
A number of researchers view farmers’ markets as an appropriate vehicle for
re-embedding food markets into communities (O’Hara & Stagl, 2001, Feenstra, 2002,
Lyson, 2005). Amidst astounding growth in the number of farmers’ markets in the
United States in recent decades, many markets struggle and fail. Recent research
suggests that...
Larval mortality of leafcutting bee, Megachile pacifica (Panzer)
(= rotundata (F.)), is high, usually exceeding 50%. Parasites and
predators are not a limiting factor in the survival of the progeny.
The disease chalk brood has been an important mortality factor since
1974. Inadequate food supply, pollen and nectar, may affect...
A time-domain model was developed to predict the fluid/structure
interaction of a three-dimensional deformable body in a fluid domain subject to
long-crested finite amplitude waves. These nonlinear waves induce transient
motion in the body. In turn, the interaction of the body with the waves modifies
the wave field, causing additional...
Pheromones are chemical cues produced by organisms that affect the behavior and/or physiology of conspecifics. The orchestration of reproductive behaviors in many animals depends on the expression of sex pheromones. In insects, intraspecific variation in sex pheromone expression is commonly observed and often influences social interactions between individuals. To what...
The objectives of this study were to quantify and describe:
(1) the major plant communities and their distribution, (2) the
distribution and movement patterns of large herbivores relative to
water, topography, and plant communities, (3) the daily activity
patterns of each herbivore, and (4) the borne range size of wild...
The western cherry fruit fly, Rhagoletis indifferens
Curran, was studied to determine the suitability of the
sterile insect technique for its control. To obtain
insect material, field collection of maggots is preferred
to sifting of soil or rearing on artificial diet.
The western cherry fruit fly is strictly univoltine;
only...