• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 965
  • 137
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 2102
  • 393
  • 271
  • 211
  • 204
  • 197
  • 189
  • 170
  • 169
  • 166
  • 159
  • 153
  • 149
  • 143
  • 131
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
391

A test of the differentiation of soil series within the Willamette catena

Pomerening, James A. 10 June 1960 (has links)
Graduation date: 1961
392

Prescribing politics : an examination of the local and global factors which govern access to "atypical" psychotropic medications for Oregon's unfunded clients

Maxey, Judith L. 10 March 2000 (has links)
This thesis is based on a study conducted for the state of Oregon's Office of Mental Health Services (OMHS). OMHS' primary research objectives included 1) the identification of the unfunded population (individuals who are uninsured and ineligible for Medicaid) who seek services at community mental health programs and 2) an examination of this group's access to atypical antipsychotic and antidepressant medications. OMHS sought this data in order to inform legislative decisions regarding a forthcoming state budget proposal for a specialized atypicals fund. The author collected ethnographic data through semi-structured interviews with 57 mental health clinicians and 41 mental health advocates throughout Multnomah, Linn and Lincoln counties. While answers to the primary research objectives were inconclusive, the qualitative data characterizes the target population and contextualizes the unfunded client's medication access issues at county-related mental health clinics. Specifically, the study results indicate that 1) the complex characteristics of the unfunded population and the inadequacies of the available medication resource programs should be examined more thoroughly before allocating appropriated funds, 2) insufficient mental health services in general is the foremost problem for unfunded clients, and that which contributes to difficulties in accessing psychotropic medications, and 3) appropriated funds from the state's budget would not adequately resolve the medication needs for the target population. The study findings suggest that the state's concern with atypical medications overshadows existing practical, everyday problems in the clinics. The author analyzes the study from a Critical Medical Anthropology perspective, examining the relationships between the global and local contexts surrounding atypical medications, and discussing the practical use of the research data. From this perspective, the state's preoccupation with supplying atypical medications for the target population appears to be driven more by the pharmaceutical industry's profit-making interests and the historical role of the public psychiatric field than by quality health care decisions. The author also discusses medical hegemony in terms of the psychiatric field, and the ways in which this effects the asymmetrical power within the Oregon mental health system. / Graduation date: 2000
393

An in-situ experiment on the effects of zooplankton grazing and nutrient regeneration on the phytoplankton of Yaquina Bay, Oregon

Deason, Ellen Elizabeth 15 January 1975 (has links)
Natural populations of phytoplankton from Yaquina Bay, Oregon, were incubated in large polyethelene bags in- situ, with and without the natural assemblage of zooplankton. Samples were taken daily for two weeks in April, 1974. The biomass of phytoplankton in the bag without grazers reached values two to three times the biomass of phytoplankton in the bag with grazers. Sixty-eight to 93% of the cells in the bag without zooplankton were Thalassiosira fluviatilis, while the major species in the bag with zooplankton were T. fluviatilis, T. decipiens and Chaetoceros debilis, no one of which ever accounted for more than 40% of the cells. Nitrate-nitrite became depleted two days earlier in the bag without grazers and urea and ammonia values were higher in the bag with the grazers. Primary productivity, per unit cell volume, was higher in the grazed bag following nutrient depletion, suggesting some productivity enhancement by grazers. Physiological parameters indicate that the cells in the bag with zooplankton were richer in carbon, nitrogen and chlorophyll a, a higher percentage of the chlorophyll was degraded to phaeophytin and carbon to nitrogen ratios were lower. Data obtained from the bag with zooplankton were similar in range to data from the bay. The results support the contention that zooplankton can have a large effect on phytoplankton in terms of biomass, species composition, productivity and physiological state. / Graduation date: 1975
394

Geothermal exploration by telluric currents in the Klamath Falls area, Oregon

Tang, Rex Wai-yuen 24 April 1974 (has links)
Geothermal resources are characterized by a very low electrical resistivity of the reservoir formations. The application of electrical methods in the reconnaissance type exploration for such resources is discussed. It is concluded that the magneto-telluric method is very well suited for this purpose. In 1971 and 1972 a reconnaissance type magneto-telluric field program was carried out in southern and eastern Oregon by the Geophysics Group at Oregon State University. In order to reduce the field effort, the magnetic data were obtained from a fixed base station at Corvallis. Only the electrical field components were measured at the various field stations. Ten stations were occupied in the Klamath Falls area, six in central and eastern Oregon and one in the Willamette Valley. Impedance data were obtained in the .025 to 0.05 Hz frequency band of the Pc 3 micropulsations. The data were analysed on the basis of an individual event method. Only magnetic-telluric events with a good correlation are taken into account. The resulting apparent resistivities display some correlation with known geothermal manifestations in the region. The lowest resistivities of the order of 10 ohm-meters were recorded in the Klamath Falls region and at a station near Vale in eastern Oregon. As common in magneto-telluric work, the data display a considerable variability, irregular scattering and anisotropy. The results are encouraging in that they appear to indicate that the magneto-telluric method is a useful reconnaissance method in the regional exploration for geothermal resources. / Graduation date: 1974
395

The Erosion of Siletz Spit, Oregon

Rea, Campbell Cary 13 December 1974 (has links)
Siletz Bay is a drowned river valley filled with Holocene alluvial and estuarine sediments and is separated from the ocean by a sand spit 3.8 km in length. Since the area was settled by white man in the 1890's, the bay has apparently experienced rapid siltation, due to increased farming and logging. This along with the damming of the Siletz River sloughs has altered circulation patterns in the bay. Deflection of the Siletz River flow by the prograding Drift Creek delta has caused 105 m of erosion since 1912 on the east side of Siletz Spit. The ocean side of the spit suffers periodic erosional episodes separated by periods of accretion and dune building. The most recent and publicized erosion occurred during the winter of 1972-73 when it was feared that the spit might be breached; one partially constructed house was lost and three others were saved only by timely riprapping. A sand mining operation may have aggravated the recent erosion by disrupting the sand budget, the balance of sand additions and losses from the beach. All of the foredune on the spit has been stabilized by dune grass and much of it has been riprapped. The long term effects of stabilization and riprapping are uncertain. / Graduation date: 1975
396

The distribution of intertidal diatoms associated with the sediments of Yaquina Estuary, Oregon

Amspoker, Michael C. 17 March 1977 (has links)
Sediment samples were collected from eight sampling sites along the Yaquina Estuary, Oregon from Yaquina Bay to Elk City near the head of the estuary. Samples were collected in November 1973, February 1974, May 1974 and August 1974 from two or three intertidal levels depending on the magnitude of the intertidal area exposed at low tide. Concurrent sediment and water samples were obtained for the determination of water temperature, salinity, sediment size, and percentage of organic carbon and cabonate in each sample. Incident light and exposure period data were obtained for the sampling year. A total of 36,564 diatoms identified and counted in 71 samples was separated into 390 taxa (species or varieties). Of the 390 taxa, 31%, representing 30% of the total cell count, could not be identified from available literature. The relative abundance values of the taxa were utilized for the comparisons of several community composition parameters (the Information measure, Simpson's diversity index, redundancy, niche breadth, and a measure of similarity) which were used for comparisons of spatial and temporal distributions of sediment-associated diatom assemblages within the estuary. Multivariate analyses (clustering, disciminant analysis, principal components, canonical correlation) of species and environmental data were employed to analyze the distribution of sediment-associated diatom assemblages relative to the sampling strategy and to environmental gradients. The distribution of sediment-associated diatoms in Yaquina Estuary was regulated primarily by mean salinity and characteristics of the sediment. Above Yaquina Bay the prominent taxa exhibited overlapping distributions along the salinity gradient to a location in brackish water where the mean salinity was approximately 5°/oo. Here, a relatively sharp discontinuity in the diatom flora existed which appeared to be the product of the biochemical and biophysical mechanisms involved in osmotic regulation of mesohalobian and oligohalobian assemblages. Relatively large disparities in the structure of sediment-associated diatom assemblages were found within relatively small local areas of Yaquina Bay. These differences were attributed to the properties of the sediment, Responses of the diatom assemblages to light intensity, temperature and exposure to intertidal emergence were not obvious. Approximately one-half of the numerical variation in the diatom flora apparently was related to factors other than the physical and chemical variables considered in this study. Comparisons of previous distributional surveys in Yaquina Estuary indicated that the diatom flora associated with the sediments was dissimilar in species composition to proximal epilithic, epiphytic and planktonic diatom assemblages. Species diversity was generally high throughout the intertidal sediments, irrespective of tidal height and season, while redundancy was generally low. High diversity values may represent contamination of samples, behavioral-physiological adaptations of the sediment flora, or the spatial heterogeneity of intertidal sediments. / Graduation date: 1977
397

Community analysis of the Wyoming big sagebrush alliance and functional role of Wyoming big sagebrush

Davies, Kirk W. 19 September 2005 (has links)
This study consisted of two research projects in the Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh) alliance, the most extensive of the big sagebrush complex in the Intermountain West. In the first project, we intensively sampled 107 relatively undisturbed, late seral Wyoming big sagebrush sites across the High Desert, Humboldt, and western Snake River Ecological Provinces to investigate vegetation heterogeneity and the relationship of environmental factors with vegetation characteristics. Vegetation characteristics were highly variable across the region. Perennial grass and total herbaceous cover varied more than six and sevenfold, respectively between minimum and maximum values. Sagebrush cover averaged 12%, but ranged between 3 and 25%. With the exception of perennial grass cover (p<0.0001, r²=0.52), limited variability in other vegetation characteristics was explained by environmental variables. In the second project, we investigated the functional role of Wyoming big sagebrush by using undisturbed and sagebrush removed (with burning) treatments and comparing vegetation and microsite characteristics under (subcanopy) to between sagebrush canopy (interspace) zones. Wyoming big sagebrush influenced associated vegetation and microsites. On sites receiving high incidental radiation, perennial grass and total herbaceous cover and density were greater in the subcanopy than interspace zones (p<0.05). On north aspects, these differences were not as pronounced suggesting sagebrush's influence on associated vegetation is site dependent. Temperature extremes were mediated and soil water content was greater in the subcanopy than interspace zones during the growing season. Results indicated that the subcanopy zone can be a more favorable environment to herbaceous vegetation than the interspace zone. Wyoming big sagebrush is important to community resource capture and use. Plots with sagebrush had greater soil water content at the start of the growing season and produced more total biomass compared to where sagebrush had been removed in both post-fire years (p<0.05). However, higher Thurber's needlegrass photosynthetic rates and greater herbaceous cover and production where sagebrush had been removed suggested that more resources were available to herbaceous vegetation in the absence of sagebrush. / Graduation date: 2006
398

A statistical study of the correlation between the surface and surface geostrophic winds in the Wilamette Valley

Andrews, Leta 23 October 1974 (has links)
Relationships among the surface wind, horizontal synoptic-scale pressure gradient and topography are studied in the Willamette Valley in western Oregon. Terrain features alter the standard surface wind-pressure gradient relationship such that the angle between the surface wind and the surface geostrophic wind is most frequently 60°. In winter the surface flow is predominantly southerly and surface geostrophic flow varies from southerly to westerly. Little diurnal change occurs in the average surface wind, the average surface geostrophic wind and their relationship with each other because the air in the valley is generally stably stratified throughout the day. Partially in response to the northward extension of the subtropical anticyclone summertime surface winds and surface geostrophic winds are northerly, except during afternoon episodes of marine air invasion when surface winds are westerly. The pressure gradient is 88% less intense in summer but the ratio of the magnitudes of the surface wind and surface geostrophic wind, R, is 125% greater than in winter. However, a sharp summertime morning maximum in R of -0.67 is diminished by early afternoon as differential surface heating establishes a strong afternoon pressure gradient. When the surface geostrophic wind vector is cross-valley, the surface wind is still most frequently parallel to the valley and the surface geostrophic wind speed is largest and most variable. Because of the importance of terrain and meso-scale events, little correlation between the surface winds and synoptic-scale pressure gradient is found. / Graduation date: 1975
399

Bulldozer blades and colliding submarine mountain chains : constraints on central Oregon convergent margin tectonics from magnetics and gravity

Fleming, Sean W. 12 December 1996 (has links)
Magnetic and gravity modelling was completed along two E-W transects offshore central Oregon. These models indicate that the backstop-forming western edge of the Siletz terrane has a seaward dip of approximately 40° to 49° at 44°48'N, shallowing to ~28° at 44°1 1 'N. This is a well-determined result, given available a priori information, to a depth of ~7 km. The edge of the Siletz terrane may continue to descend at these dips to the JdF plate, but alternate geometries for the lowermost portion of the backstop are also consistent with the potential field data. The magnetic data also require progressive eastward demagnetization of the subducting JdF crust, which is most likely due to heating of the descending oceanic plate to the Curie temperature. Our southern transect reveals that Heceta Bank is cored by relatively high-density sediments (~2.54 g/cc), consistent with the model proposed by Kulm and Fowler (1974) for submarine bank formation in the Oregon convergent margin. On the basis of magnetic, gravity, and velocity data, we tentatively interpret a deeply buried, linear aseismic ridge to be present beneath the accretionary complex from about 45°N to 42°N. This ridge may collide with the backstop beneath Heceta Bank and may play a role, in concert with imbricate thrust faulting, in the formation of Heceta Bank's high density core. We also speculate that differences in depth to the JdF plate due to juxtaposition of different-aged crust across pseudofaults which intersect the coast at Nehalem and Heceta Banks may be a factor in the construction of these topographic highs. / Graduation date: 1997
400

Aeromagnetic measurements, magnetic source depths, and the Curie point isotherm in the Vale-Owyhee, Oregon geothermal area

Boler, Frances M. 29 November 1978 (has links)
Graduation date: 1979

Page generated in 0.0513 seconds