The prevalence of herbal supplement use by the elderly and factors that influence regular versus occasional use were investigated in a group of independent residents of a continuing care retirement community in Salem, Oregon. A nine-page questionnaire was delivered to 402 residents of Capital Manor; 318 questionnaires were usable (84% response rate). The majority of respondents were female (68%) and Caucasian (88%) with an age range of 65 to 100 (average 82.2 years). Twenty percent of all respondents (n=65) were herbal supplement users. Sixty-two percent of them were regular users and 39% were occasional users. The majority of users were female (68%), Caucasian (85%), and non-smokers (78%). Their age range was 65 to 91 years (mean of 79.6 years). Sixty-nine percent reported living with a spouse. They had more than a high school education (78%) and had annual household incomes above $50,000 (49%). "Books, newspapers, and magazines" (84%) were the information sources most frequently relied on for herbal supplement information, followed by "medical doctor/nurse" (72%). Forty-four percent of user households spent more than $10 per month on herbal supplements. Supermarkets (41%) and health food stores (41%) were the most popular places to purchase herbal supplements. The majority of herbal supplement users strongly agreed/agreed that taking herbal supplements would "make you feel less stress" (88%), "protect you from getting a cold" (81%), and "improve your memory" (81%). Fifty-two percent of users strongly agreed/agreed that "herbal supplements may cause side effects" and 24% strongly agreed/agreed that "herbal supplement shouldn't be taken with other medications". Gingko biloba was the most frequently used of eight herbal supplements (71% of respondents) followed by echinacea (39%) and ginseng (29%). Males were significantly more likely to use saw palmetto (claimed to prevent enlargement of the prostate gland). Eighty-three percent of herbal supplement users reported having some knowledge about possible benefits of ginkgo biloba (claimed to reduce memory loss). A belief that herbal supplements "improve your memory" was significantly associated with usage. Regular herbal supplement users were significantly more likely to agree that taking herbal supplements reduces severity of memory loss. Four factors were significantly related to herbal supplement use: age group (with age group of 75 to 84 years old more likely to be users than age groups of 65 to 74 years and age group of 85 years and over); living status (with those living with spouses being more likely to be users than those living alone), health status changes in the past year (with users being more likely to report their health status as "improved" than non-users); and physical exercise participation (with users being more likely to exercise than nonusers). The fundamental hypothesis of this study was that the frequency of use of herbal supplements among older adults would be mediated by several factors including: perceived susceptibility to and severity of chronic diseases (i.e., heart disease and cancer); perceived benefits of and barriers to herbal supplement usage; information sources; vitamin/mineral supplement usage; and perceived preventive lifestyle factors. Of these, only vitamin/mineral supplement usage was significantly associated with herbal supplement usage. Ninety-seven percent of herbal supplement users also used vitamin/mineral supplements. In addition, perception of control over health (a measure of self-efficacy) was significantly associated with herbal supplement use. The more control perceived, the more likely respondents were to be herbal supplement users. In general, the Health Belief Model did not predict frequency of herbal supplement usage (i.e., regular vs. occasional). Hence, further research is needed to focus on factors predicting herbal supplement use versus non-use. In addition, lack of awareness about risks and benefits of herbal supplement use suggests a need for education targeted at older adults. / Graduation date: 2001

Soil erosion research in the fields of agronomy, soils science and mechanics, agricultural engineering, hydrology, climatology, and other scientific disciplines has economic dimensions. In general, measurable and, at times, significant economic effects are associated with the effects of erosion in the other disciplines. Interactions between climate, soils, hydrology, and tillage practices are incorporated into a stochastic simulation model that considers twenty six combinations of five tillage systems, three initial soil depths, two soil associations, two slope classes, and two annual precipitation levels over one hundred years. The model endogeneously determines stochastic annual soil loss. Yield is a function of varying soil depth and technological advance. The model maximizes the wheat producer's objective, 100-year discounted quasi-rents from wheat production. Cumulative or total rent distributions that derive from alternative tillage systems in the different ecological circumstances are compared under stochastic dominance. In low rainfall, shallow soil areas, annual tillage systems were preferred to fallow ones, while conservation tillage dominated plow tillage. In high rainfall areas, for either shallow or deep soil, conservation tillage dominated plow tillage, while plow tillage dominated no-till. Manipulation of the tillage-associated rent distributions permitted the estimation of value-of-marginal product or willingness to pay curves (ordinary, profit-maximizing, input demand curves) that express the depth of soil as a function of its economic worth. Properties of these curves are discussed. Comparison of expected total returns and marginal returns to topsoil increments under alternative tillage systems in defined ecological circumstances paralleled the stochastic dominance results. Rankings of tillage systems by expected total returns differed between ecological areas and differed from rankings by marginal returns. Regardless of tillage system or ecological circumstances, the economic worth of each added soil increment diminished. The experiment showed that differential rates of soil loss associated with different tillage systems influence the decision to continue using or to initially invest in alternative tillages, and also influence the economically rational wheat producer's willingness to incur costs associated with soil conservation. Total and marginal rents associated with single tillages were found to vary greatly across ecological circumstances. The ability and the willingness to invest in soil conservation were somewhat divorced. This result has significance for soil conservation targeting. / Graduation date: 1986

From 1979 through 1984 the economic bases of rural Oregon counties have undergone structural change. Nonwage income, especially transfer payments, has played an important role in these changes. Demographic changes in rural counties have contributed to the growth in unearned income. The economic structure of rural Oregon counties was estimated by applying indirect export analysis techniques to secondary data. The results of the structural analysis provided the data for the econometric analysis. A conceptual model of regional growth was developed that incorporated community characteristics such as the size of the market (population) and market distance (location and commuting activity) from central place theory. This conceptual model was made operational through several econometric models which regressed basic income and community characteristics on residentiary incomes. Data limitations prevented extensive testing of the econometric models. Some bias, which affected the values of the residentiary sectors, was perceived in the estimation of exports. Two methodological improvements were attained. Firstly, the economic base of each county was estimated with sectoral groupings and data disaggregation that were better suited to the analytical techniques than is commonly applied. Secondly, a regional growth model was develped that combined basic income arguments with regional location and population arguments. The growth of expenditures by transfer payments recipients, both as a type of basic income expenditure and as a representative of retiree consumption, helped to account for the growth of residentiary income in rural counties during the early 1980's. Due to the steady growth of transfer payments, the growth of the retiree population and the decline in export earnings, policy makers should specifically consider the changing number of retirees when formulating regional development strategies. / Graduation date: 1988

The ocean fishery is an example of a common property resource industry. Behavior of commercial fishermen is determined by a complex set of economic, environmental and social factors. All of these factors contribute to the individual fisherman's success. Fishermen learn to cope with the variability inherent to their occupation. Two strategies are observed in fishing behavior: The specialist who operates exclusively in one fishery and the generalist who readily switches fisheries according to market, social or management considerations. Traditional fishery models formulated to predict the behavior of fishermen have focused on the specialist. Smith and McKelvey (1986) and McKelvey (1983, 1987) have provided analyses to suggest these two fishing strategies may co-exist in a fluctuating environment. The purpose of this study is to analyze the Oregon trawl fisheries for the presence of diversification in strategy selection. To gather the data necessary for testing the hypotheses, interviews were conducted in the trawl fisheries of Oregon, June through December 1985. Three groups of fishermen are identified according to strategy selection. Nominal effort differences and capital-to-income ratios are examined for each strategy type. Additional analysis is done to look at the components of income determination through regression analysis. Discriminant analysis is used to examine the fishermen's attitudes toward switching, risk and management concerns. Among the findings of this research is that specialists and generalists do exist but they cannot adequately characterized by exclusively economic measures. Attitudes shown on the part of the fishermen indicate they feel that management is a significant factor contributing to income variability and strategy selection. / Graduation date: 1988

Child care stability affects child and family outcomes. Stability reflects the time dimension of a child care arrangement. Although stability does not guarantee positive outcomes, instability appears to decrease the likelihood of achieving them. Some level of stability is a necessary, although not sufficient, characteristic of care that meets children's needs. Child care stability is of special concern for children in low income families because child care impacts are greatest for these children, and current welfare policies result in more low-income children in nonparental care. This study increases understanding of child care stability through (a) an analysis of findings from stability studies over 30 years, (b) an examination of relationships of the four major stability measures, and (c) presentation of results from an analysis of the stability of subsidized child care arrangements in Oregon. The analysis of stability studies documented lack of consistency in conceptualization, measures, and methodology. These inconsistencies limit comparisons of reported stability findings and confidence in estimates of child care stability that have been reported. Examination of the four stability measures found that the three child-level measures appear to describe the same construct as they are highly correlated. The fourth stability measure is at the level of the arrangement and captures a distinctly different aspect of stability. Stability levels of subsidized arrangements in Oregon appear lower than those found in nationally representative samples but similar to levels found in populations participating in public assistance programs. About a third of children had very stable care but others had high levels of instability. Fifty percent of arrangement spells ended by 3 months, even when children were observed for 36 months. The study concludes with recommendations for future research. / Graduation date: 2005

Samples of benthic organisms off the coast of Oregon, taken from depths varying from 50 to 2900 meters, have been analyzed in terms of diversity at a given station, and similarity and ecological distance to other stations. Estimates of epifauna abundance were also made. In the analysis an important distinction is made between diversity, abundance, and variety indices; the three measures are considered independent pieces of information relevant to the ecological structure of the population of interest. Two types of sampling gear were used. Large epifauna were sampled with a beam trawl. Polychaetous infauna were sampled with an anchor-box dredge. The diversity index chosen is Simpson's index; the measures of similarity and ecological distance are related. These measures are preferred because of their ease in calculation and basic simplicity. In addition these measures may be interpreted as estimates of well-defined population parameters (as Simpson has pointed out) which have straightforward probabilistic interpretation. A valid measure of diversity is one piece of relevant information necessary for elucidating the sufficient parameters of ecological systems. Therefore the methodology presented has broad application to studies of population structure. / Graduation date: 1970

Graduation date: 1971

The purpose of this research was to explore the impact of finfish bycatch on the ocean shrimp Pandalus jordani fishery using two methods. One method looked at the breakage of the shrimp by finfish bycatch in the nets. The other looked at the impact of bycatch on fishing decisions. At-sea research found that finfish bycatch contributes to the breakage of ocean shrimp. However, the impact is small relative to breakage caused by other handling procedures. Bycatch was measured from each net of a double-rigged shrimp vessel, where one side employed a Nordmore grate bycatch reduction device (BRD) and the other served as a control. Shrimp catch was controlled for BRD use and catch day, and sampled throughout processing to evaluate breakage. At greater than 50% bycatch there was a significantly higher percentage of broken shrimp in the control side than in the BRD side for samples taken at the first and third sampling point (p<0.05). After this point the differences became non-significant. The percent breakage increased from a mean 2.4% broken before placement in the hold to a mean 18.0% broken in the final product. The impact of bycatch on fishing decisions was evaluated by distributing an expanded logbook to volunteer Oregon shrimp vessels in 1998. Logbook questions addressed the reasons and time involved for running to initial fishing grounds, relocating overnight, relocating between tows, dumping tows, and modifying gear. Completed logbooks were collected from 20 vessels representing 263 trips, 1043 fishing days, and 4727 tows. A soft mesh BRD was used at some point by 25% of vessels on 8.7% of trips and 3.3% of tows. Bycatch did not figure prominently in reasons given for choice of initial fishing grounds, relocating between fishing days, or relocating between tows. Bycatch was the main reason cited for dumping tows. In total, 430 (9%) tows were dumped. The estimated weight of fish and shrimp dumped equaled 11.3% and 0.3%, respectively, of the landed shrimp catch. Pacific whiting Merluccius productus caused 81.4% of the tows dumped due to bycatch. Opportunity costs attributed to bycatch alone were equivalent to net revenue resulting from 12.3 tows or $3,203 per study vessel. At the fleet level, opportunity costs due to dumped tows totaled 1,227 effort hours, 32.4 trips, or $155,070. This equates to a 4.6% loss in gross ex-vessel revenue. / Graduation date: 2002

Landsliding is a significant contributor to continuous erosion of the 150-mile northern Oregon coast. Direct loss of land to the sea by landslides occurs along 47 percent of the coast. The remaining 53 percent has minor shifting of sand along depositional areas such as spits and dunes. These minor movements alter coastal topography but do not erode material directly into the sea. The type of landsliding is principally controlled by the lithology of the coastline. Landslides are classified on the basis of two features: the lithology of the coastal material in the slide and the type of movement expressed by the overall shape of the slide. Slump occurs in deeply weathered sedimentary rocks and in marine terrace sands overlying seaward-dipping rocks. Rock and debris fall are mainly confined to headlands. Block glides develop along bedding planes of relatively unweathered sandstone. Debris shift occurs in thick terrace and dune sand deposits in which no slip surface is defined. Factors contributing to the cause of coastal landslides include high precipitation, easily weathered rock, and high coastal wave energy. Frequency of reported landslides is related to periods of high precipitation and high wave energy. Although rock weathering is continuous throughout the year, the final phase in disruption of slope equilibrium often occurs during winter storm conditions. Landslides on headlands and adjacent coastlines disrupt the most extensive land area. Wave refraction directly influences this relationship by focusing wave energy on promentories and on the coastline within one mile of the headlands. Distribution of coarse and fine beach material is affected by refraction in restricted coves. Severe coastal erosion has taken place in local areas. The average rates of retreat vary according to the lithology of the coastline, and have been determined as follows: unconsolidated sand and gravel - 23 feet per year; marine terrace sands overlying sandstone and clay - 20 feet per year; marine terrace sands overlying mudstone and sandy shales - 6.5 feet per year. Knowledge of the processes of marine erosion applied to local cliff protection measures can assist in increasing the effectiveness of erosion control attempts. / Graduation date: 1964

The purpose of this thesis is to provide a first look at the spatial and temporal distributions of dissolved organic material (DOM) off the Oregon coast of North America. While this paper is not a comprehensive examination of these distributions, several patterns are identified as promising candidates for continued research. Most of the data presented was acquired during a strong El Nino event. The DOM data is presented as dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) and is accompanied by temperature, salinity, nitrate plus nitrite (N+N), ammonium, silicate, chlorophyll, total organic carbon (TOC), particulate organic carbon (POC), total nitrogen (TN), total organic nitrogen (TON), and zooplankton biomass measurements. During July 1997, we examined the distribution of DOM in the surface waters off the Oregon and Southern Washington coasts. Eleven east-west transects were sampled from nearshore waters to 190km offshore. DOC concentrations as high as 180 iM were observed in the Columbia River plume. Patterns in the DOC distribution were also associated with upwelling regions, an offshore coastal jet, and an oligotrophic water mass in the northern portion of our study area. Beginning with the July 1997 study and continuing until July 1998, samples were collected on weekly and seasonal time scales at station NH-05, located 9km offshore from Newport, Oregon. Various problems have limited our seasonal comparisons, but we were able to collect high quality data depicting the changes in organic matter partitioning during a phytoplankton bloom and its decline during a two month period from mid-July through mid-September in 1997. During the bloom, POC increased dramatically, but DOC decreased. Possible explanations for this decrease and for changes in the C/N ratio of the DOM during the bloom are explored. Suggestions for future research are presented in the final chapter. / Graduation date: 2000