Timber management of coastal watersheds in southwest Oregon has been complicated by the need to protect anadromous fish habitat from accelerated stream sedimentation resulting from management activity. The rugged terrain of the Elk and Sixes River basins is underlain by the complex geological province of the Klamath Mountains, in which landslides are a common, natural, and important process of sediment production. A landslide investigation, using sequential aerial photographs which covered a time period of 37 years, was used to determine relationships between mass-wasting, geologic types, and timber harvest practices. Averaged over all rock types, harvested areas showed an increase in failure rate of 7 times, and roaded areas an increase of 48 times that of forested terrain. Terrane underlain by dioritic intrusions was the most sensitive to road-related activity, with an increase in failure rate of up to 108 times that of comparable unmanaged land. The complexity of lithologies and deformational history in the area strongly influence slope morphology, and produces characteristic soil types which experience predictable modes and rates of slope failure. Debris slides and torrents are the dominant form of mass-wasting in dioritic and Cretaceous sedimentary terrane. Areas underlain by more clay-rich metamorphic bedrock are prone to slumps and planar streambank failures. Stream morphology is profoundly influenced by both rock type and geologic structure. Within an area characterized by steep, deeply incised streams, several persistent low-gradient reaches were delineated. These low-gradient stream reaches occur where (1) large landslides have locally raised channel bed elevation and (2) valley-floor widening has occurred in sheared rocks along fault zones or in more readily eroded rock types upstream of rock types resistant to fluvial erosion. / Graduation date: 1987

The purposes of this study were first to determine if there were significant differences in living environment press, i.e., the pressure on an individual to behave in a certain way, between those fraternity chapters that had the highest freshman pledge retention rates and those that had the lowest. If significant differences were determined to exist, the second purpose was to investigate how those differences related to differences in the retention rates for freshman fraternity pledges. The data were obtained from the records of all freshman pledges in the Oregon State University fraternity system for a four-year period. From these data the high pledge retention and low pledge retention fraternities were determined. The sample for the remainder of this study was two of the three highest and two of the three lowest pledge retention fraternities. The highest and lowest pledge retention fraternities were eliminated. Analyses included: Pearson Correlation Coefficients to determine if there were significant correlations between retention of pledges in the fraternity system and six factors involving grades and the number of members and pledges living in the fraternities; two-way, fixed analyses of variance to determine if there were significant differences between the high retention fraternities (HRFs) and the low retention fraternities (LRFs) with respect to pledge high school grade point averages and Scholastic Aptitude Test scores; chi square contingencies to determine if there were significant differences between the HRFs and the LRFs with respect to 14 different characteristic, background, and satisfaction variables; and F-test analyses to determine if there were significant living environment differences between the HRFs and the LRFs on each of the subscales of the University Residence Environment Scale, Form R. The conclusions of the study were: 1. Neither high school nor college grades, SAT scores, nor individual characteristics, background, and satisfaction levels can be used to define differences in pledge retention between the HRF and LRF houses. 2. The differences within the living environment, and primarily the relationship dimension of that environment, of the two groups offer the best explanation of the pledge retention differences between the two groups. 3. The overt pressure exerted by the LRFs on their pledges to study and achieve academic success did not result in greater academic success than in HRFs, but did tend to limit the degree of social integration achieved by their pledges. 4. Social integration has a significant positive impact on pledge retention, while overt pressure toward academic integration has a probable negative impact on pledge retention. 5. Successful social integration, while having a positive impact on pledge retention, does not have a negative impact on academic performance. In fact, the impact on academic performance may be positive. 6. A crucial element in the Tinto (1987) model should be a relationship building block within the peer group interactin portion of the social system. Recommendations for further study were made. / Graduation date: 1991

The purpose of this investigation was to examine the influence of selected historical, fiscal, and organizational factors on enrollment patterns in Oregon Community Colleges during the academic years 1978-79, 1981-82, and 1984-85. Oregon was selected insofar as it is one of the few remaining states which observes the principle of local control and maintains state institutional reimbursement for five categories of enrollment, including adult self-improvement. The 13 Oregon community colleges formed between 1961 and 1971 provided the population for this study. A telephone instrument was developed to gather historical data from the president of each college. Additional information was gathered from state agencies. The data collected were analyzed using stepwise regression and the determination of simple correlation coefficients. The five dependent variables were each of the reimbursable categories of enrollment. It was hypothesized that 19 separate factors, the independent variables, could have influenced the reimbursable categories. Research findings identified the following influences upon FTE by enrollment categories: 1. instructional staffing patterns for increasing transfer and vocational preparatory; 2. presidential ratings of vocational education for increasing vocational preparatory; 3. stability of property taxpayer support for increasing transfer; 4. unsuccessful budget elections for increasing developmental education; and 5. unemployment for decreasing vocational preparatory and increasing transfer. However, none of the factors considered had an impact upon vocational supplemental and self-improvement FTE categories. In addition, the completion of this investigation demonstrated that it is possible to develop a predictive model for enrollments by category. Although a number of the factors considered did not prove to be significant, the findings from this study provided an initial research model that can be used to facilitate the examination of other factors which may influence predictive enrollment modeling by category in various settings. Further studies should include consideration of additional variables, including community characteristics and population migration rates as well as the impact of local control on enrollment trends. The following variables should be subject to continuing reexamination: President's ranking and rating of enrollment categories; the impact of budgetary elections, subject to improved methodology; state funding achievement for years when funding redistributions occur; changes of chief executive officer and changes at the division and/or department level, in comparison to changes of higher level administrators. In addition, those factors which constitute barriers placed between unemployed workers and vocational training should be closely examined. / Graduation date: 1991

Graduation date: 1990

This thesis addressed the potential of endemic predaceous and parasitic arthropods of the Hood River Valley, Oregon to suppress the pear psylla, Cacopsylla pyricola F8rster. Natural enemies adequately suppressed psylla in three of seven unsprayed orchards of differing vegetational settings, orchard age, and size. Relatively few psylla natural enemies dispersed to unsprayed pear mini-orchards, dspite abundant populations on surrounding noncultivated vegetation. Pear psylla natural enemies were more abundant on arboreal rather than herbaceous non-pear hosts. Selective programs of pear pest control based on diflubenzuron were moderately successful in controlling the pear psylla, with natural enemies aiding in suppression in six of fourteen commercial trials of selective programs. In both unsprayed and commercial pear orchards, late-season psylla densities appeared to be best suppressed when levels of natural enemies were high during early-season. Classification analysis confirmed that orchard site, chemical regime, type (mini- or commercial), and season affected proportions of natural enemies and their pear psylla prey. Complexes of natural enemies and pear psylla immatures from commercial orchards where biological control was successfully demonstrated were taxonomically similar. Effective natural enemy complexes in commercial orchards were characterized by earwigs, lacewing larvae, and moderate proportions of pear psylla immatures during early season and Deraeocoris brevis, earwigs, and lacewings during mid-season. Plagiognathous guttatipes (Uhler) or Diaphnocoris provancheri (Burque) dominated effective natural enemy seasonal complexes at each of two mini-orchards. The functional response to pear psylla eggs was measured for five predaceous mirids. Functional response parameters differed among species and their life-stages, but all destroyed large numbers of psylla eggs. Further experimental directions for the implementation of pear psylla biological control are proposed. General investigative strategies include: (1) augment natural enemies on non-pear vegetation adjacent to the target orchard, and (2) modify the orchard habitat to both encourage natural enemy colonization and allow permanent complexes of natural enemies to develop. Specific tactics include: plant hedgerows of filbert or willow, cultivate snakeflies, introduce Anthocoris nemoralis, adjust early season psylla densities with suitable timing and kind of delayed dormant sprays, using a more effective selective psyllacide, and reduce winter pruning to allow development of natural enemies which overwinter in the egg stage. / Graduation date: 1992

Roundabouts have become an alternative for traditional intersections due to the safer operational performance. Previous research has provided crash modification factors (CMFs) as a criterion based on before-after studies as to evaluate the safety performance of roundabouts. One drawback of assessment based on crash modification factors, however, is that a before-after study includes too many variations at a time that it only provides a general idea of the safety performance for roundabouts. Since the industrial world is interested in the safety outcome of converting traditional intersections to roundabouts, safety performance functions (SPFs) will provide more specific details on estimating crashes than that of crash modification factors. This thesis will adopt a similar methodology that has been used in the current Highway Safety Manual (HSM) to develop safety performance functions for roundabouts based on Oregon data. The outcome of this thesis will help the Oregon Department of Transportation (ODOT) to evaluate existing roundabouts in the State of Oregon. Furthermore, this thesis will function as an additional case study from Oregon to contribute to the national effort of evaluating the safety performance of roundabouts. / Graduation date: 2013

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In western Oregon the titratable acidity of grapes at harvest may in some seasons be higher than desirable for making quality wine, due to the retention of malic acid. The purposes of this study were 1) to investigate the effects of a vineyard cultural practice, cluster exposure at veraison by basal leaf removal, as a means of reducing the malate content and titratable acidity of grapes, and 2) to develop a rapid, simple, and inexpensive test procedure by which smaller wineries and vineyards could evaluate the effects of their own field experiments on the malate and tartrate content of their grapes. 1. At veraison, clusters of Chardonnay grapes were a) exposed to the sun by removal of all leaves opposite or below the clusters, b) treated as in a) but shaded with shadecloth, c) exposed to the sun by tying back leaves opposite or below the clusters, or d) left untreated as a control. Clusters of White Riesling were exposed to the sun by similar leaf removal a) 10 days before veraison, b) 10 days after veraison, or c) untreated. Clusters of Pinot Noir were exposed a) at veraison, b) 2 weeks after veraison, or c) untreated. Exposed clusters received 3 to 3.5 times more light than shaded clusters and up to 32% more heat, with temperature differences between exposed and shaded treatments being most pronounced during cool, sunny weather. None of the treatments had any effect on juice or berry malate, tartrate, or potassium content; however, exposed clusters of Pinot Noir had a lower pH (.03) and higher titratable acidity (.06%) than the control at harvest. Cluster exposure of Chardonnay increased sunburning of grapes, and cluster exposure of Pinot Noir at veraison caused a 1% reduction in juice soluble solids concentration at harvest. The detrimental effects of cluster exposure by basal leaf removal at veraison, as well as the lack of any major effect on the acid content of the berries, suggest that the practice has no value for acid reduction during a warm, dry maturation season in western Oregon. 2. A rapid, simple procedure for the estimation of the malate and tartrate content of grape juice is described. The procedure, which requires only a pH meter for instrumentation, does not directly measure malate and tartrate but instead measures their buffering effect. Samples are titrated between pH 2.70-3.00 and pH 4.50-4.80 and the titrant volumes required are compared to two sets of empirically derived standard curves. The malate and tartrate composition of the sample may be determined by a graphical or algebraic method. The use of the estimation method, its advantages, and its limitations are illustrated with different viticultural trials. The estimation error (estimated value - measured value) was influenced by many factors including maturity, season, vineyard location, and cultivar. Standard deviations of the estimation error for malate and tartrate in mature grapes were equal to 9% and 15%, respectively, of the mean malate and tartrate concentrations in pooled Pinot Noir and Chardonnay samples from different vineyards and years. The estimation error is probably due to interference from other buffers present in juice. Although not as accurate as existing analytical methods, the estimation method appears potentially useful for determining relative effects of treatments in vineyard trials where analytical equipment is unavailable or for monitoring malate decline during maturation of grapes. / Graduation date: 1987

The climate and the exchange of heat between atmosphere and ocean are examined in a region adjacent to Washington and Oregon, and in two sub-regions adjacent to Oregon. The sub-regions are chosen such that one contains the nearshore upwelling region and the other borders it on the seaward side. The data (ship weather observations, 1953 to 1962) reveal the general seasonal variation of climatic factors in the regions studied and the effects of the nearshore upwelling of cold water on the climate over the coastal ocean region and the adjacent coastal land mass. In the nearshore sub-region, summer values of temperature (air, wet bulb, and sea surface) are lower than those to seaward, but winter values are higher inshore than to seaward. The effects of these differences, and of other factors, on the heat exchange processes are examined with the use of empirical equations. It is seen that the processes of evaporation and conduction are suppressed considerably and net long wave radiation is slightly suppressed in the upwelling region during the summer. The effects of the reduction of heat loss to the atmosphere in the summer upwelling region on the climate of coastal Oregon are seen to be a slight reduction of air temperatures and, despite reduced evaporation, a very slight increase of relative humidity. Monthly means of daily net heat exchange between the sea and the atmosphere are examined and correlated with the difference between monthly means of the heat used per day in the oceanic evaporation process and the monthly means of daily totals of heat estimated to be used in the evaporation from a shallow pan under climatic conditions identical to those accompanying the net heat exchange and oceanic evaporation. / Graduation date: 1965

Graduation date: 1929