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  • 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.
91

A Tourism Impact Index for Water-Based Natural Attractions Field-Tested in Subarctic and Maritime Climates

Fox, Jason 01 July 2019 (has links)
Tourism in cold and cool-climate regions is largely characterized by recreational and sightseeing activities at water-based natural attractions such as beaches, coastal cliffs, and waterfalls. While the economic benefits of the tourism industry can contribute to a sustainable future for these regions, the environmental implications of a hastilydeveloped industry cannot be ignored given that cold-climate and cool-climate landscapes are at risk of rapid environmental change from a warming climate and other environmental concerns. This study consisted of the development of the Tourism Impact Index for Water-Based Natural Sites, the first of its kind, and its application and refinement in the field at various water-based natural tourism sites in Iceland and the Washington Olympic Peninsula. As no direct precedent for the index exists, the creation of the initial index draft was informed by other environmental indices available from the literature in related disciplines. The index contains 44 visually-assessed indicators, each scored on a scale of zero to three regarding potential severity of environmental impact. As the index was applied throughout the two study regions, improvements were incorporated into the design so as to create a well-validated product that may be shared with tourism managers and developers and with researchers to aid in the continued expansion of literature on tourism-environment interactions.
92

VISUALIZING BARRIER DUNE TOPOGRAPHIC STATE SPACE AND INFERENCE OF RESILIENCE PROPERTIES

Hsu, Li-Chih 01 January 2019 (has links)
The linkage between barrier island morphologies and dune topographies, vegetation, and biogeomorphic feedbacks, has been examined. The two-fold stability domain (i.e., overwash-resisting and overwash-reinforcing stability domains) model from case studies in a couple of islands along the Georgia Bight and Virginia coast has been proposed to examine the resilience properties in the barrier dune systems. Thus, there is a need to examine geographic variations in the dune topography among and within islands. Meanwhile, previous studies just analyzed and compared dune topographies based on transect-based point elevations or dune crest elevations; therefore, it is necessary to further examine dune topography in terms of multiple patterns and processes across scales. In this dissertation, I develop and deploy a cross-scale data model developed from resilience theory to represent and compare dune topographies across twelve islands over approximately 2,050 kilometers of the US southeastern Atlantic coast. Three sets of topographic variables were employed to summarize the cross-scale structure of topography (elevational statistics, patch indices, and the continuous surface properties). These metrics differed in their degree of spatial explicitness, their level of measurement, and association with patch or gradient paradigms. Topographic metrics were derived from digital elevation models (DEMs) of dune topographies constructed from airborne Light Detection and Ranging (LiDAR). These topographic metrics were used to construct dune topographic state space to investigate and visualize the cross-scale structure of dune topography. This study investigated (1) dune topography and landscape similarity among barrier islands in different barrier island morphologic contexts, (2) the differences in barrier island dune topographies and their resilience properties across large geographic extents, and (3) how geomorphic and biogeomorphic processes are related to resilience prosperities. The findings are summarized below. First, dune topography varies according to island morphologies of the Virginia coast; however, local controls (such as human modification of the shore or shoreline accretion and erosion) also play an important role in shaping dune topographies. Compared with tide-dominated islands, wave-dominated islands exhibited more convergence in dune topographies. Second, the dune landscapes of the Virginia Barrier Islands have a poorly consistent spatial structure, along with strong collinearity among elevational variables and landscape indices, which reflects the rapid retreat and erosion along the coast. The dune landscapes of the Georgia Bight have a more consistent spatial structure and a greater dimensionality in state space. Thus, the weaker multicollinearity and higher dimensionality in the dataset reflect their potential for resilience. Last, islands of different elevations may have similar dune topography characteristics due to the difference in resistance and resilience. Notwithstanding the geographic variability in geomorphic and biogeomorphic processes, convergence in dune topography exists, which is evidenced by the response curves of the topographic metrics that are correlated with both axes. This work demonstrates the usefulness of different representations of dune topography by cross-scale data modeling. Also, the two existing models of barrier island dune states were integrated to form a conceptual model that illuminates different, but complementary, resilience properties in the barrier dune system. The differences in dune topographies and resilience properties were detected in state space, and this information offers guidance for future study’s field site selections.
93

Transportation and Land Use Patterns: Monitoring Urban Change Using Aerial Photography, Portland, Oregon 1925-1945

Fyfield, Paul Hagen 01 January 2003 (has links)
American urban neighborhoods are a patchwork; the spatial arrangement of types is a reflection of the dominant transportation technology at the time of their development. The earliest suburban areas were made accessible by fixed route systems such as the electric streetcar, followed by the widespread adoption of the automobile; each transportation epoch resulted in characteristic patterns of land use. This study uses aerial photographic coverage of Portland, Oregon from the years 1925, 1936, and 1945, a time of decline for the once popular trolley lines and dramatic increase in automobile usage, to monitor change within the residential areas of Portland's east side over a twenty year period. Classic economic models of the time acknowledged transportation as a force shaping the city; modem ideas in urban planning such as Traditional Neighborhood Design and Transit Oriented Development look to pre-automobile urban form as a means to reduce automobile use and its negative implications. This study uses variables of housing density and street connectivity derived from the aerial photography; the measured values of these variables are then considered for their spatial and temporal distribution using statistical comparisons. The results are compared to ideas within the urban models and current thinking about urban morphology. While generally consistent with the expected patterns, deviations and differences between the two variables are considered for their implications. Models offer a simplified version of the growth of American cities, considering only a few of the many aspects of a dynamic environment. By isolating on these variables of density and connectivity, a greater understanding of their role in arriving at the modem residential urban environment may be reached, and this understanding can add to the discourse in current planning debates.
94

Netarts Bay, Oregon: an assessment of human impact on an estuarine system

McCallum, Larry D. 01 January 1977 (has links)
Problems associated with planning the future use of estuarine areas stem from: A lack of knowledge on the critical aspects of the system. Inability to predict the future changes which will occur within the system in order to effectively manage the resource base. These difficulties lie in the fact that changes within the system occur because of both "natural" and "cultural" conditions. The thesis hypothesis and subsequent research is to describe the physical changes that have occurred within the Netarts system, primarily due to man's impact. Types of data gathered for the analysis includes that on historical and current land use activities, current research findings on system characteristics, and independent research on shoreline changes and vegetation composition. Much of the historical data were taken from early manuscripts and publications. Current research data were obtained from several engineering studies of the bay, as well as a baseline study of Netarts funded by a grant from the National Science Foundation and Oregon State University. This study included an inventory of man's utilization of the resource base. Methods utilized in data analysis included aerial photo-interpretation, planimetric measurement of shoreline and vegetative alterations, and on-site inventory of current shoreline and vegetation changes. Results of the research have shown that it is possible to measure and describe changes within the Netarts Bay system. Specific findings include: A decrease in sandspit volume of nine percent between 1942 and 1974 due to construction of a boat basin and fill. Occurrence of marsh progradation in all marsh areas with sedge and low sand type showing the greatest increases between 1939-1962. A decrease in rate of marsh progradation from 1962-1974. A total decrease in tidal prism of the bay between 1957-1969 as measured by cross sectional areas. The rate of decrease is occurring at a faster rate south of the mouth of Whiskey Creek. Destruction of Chum salmon fisheries and native oyster populations due to over-harvesting and siltation. Destruction of Gaper clam beds along the eastern shore of the bay and increased erosion of the shore, due to road fill and road construction. The results of the research and subsequent findings show that it is possible to describe an estuary as a "system" that has applicability for future development of a land and water use model for an estuary.
95

The Transnational Networks of Cultural Commodities: Peruvian Food in San Francisco

Brain, Kelsey Ann 01 January 2010 (has links)
In a setting of increased movement, communication, and flows across space, commodity chain networks bring valued cultural commodities to transnational communities. This research examines the networks bringing foreign cuisine ingredients to Peruvian transnational communities in San Francisco, California. It seeks to answer three inter-related questions: 1) What are the origins and transportation networks bringing Peruvian food items to San Francisco; 2) Who controls and benefits from the movement of this food and resulting capital; and 3) How do networks vary for different classes of end consumers? Chefs of ten Peruvian restaurants and ten Peruvian migrants in the San Francisco area are interviewed to determine primary imported Peruvian food items and their cultural value. Interviews with representatives of major importing companies as well as searches of import/export databases are used to trace network flows. Flow maps follow the food items from the point of origin to the point of consumption and visually demonstrate the flow of resulting capital. Additionally, network maps are divided into three categories determined by end consumer: expensive restaurant, moderate restaurant, and home cooking. Maps are analyzed for differences between these categories. Finally, a narrative analysis discusses the role of migrants' cultural eating habits in San Francisco and its connection to transnational commodity networks. The research offers commentary on the role of food as a cultural marker for Peruvian transnationals and on the relations of power within the commodity network. This research unites economy and culture at the local and global scales while showing how “things” are imbued with cultural meaning during the processes of production to consumption on a transnational network.
96

Spatial variations in the intra-urban response to a noise source

Conder, Wilbur David 01 May 1973 (has links)
Most research on the urban sonic environment has been recent. One finding has been that physical noise exposure indices calibrate poorly with human noise response. The vagaries of human response to noise have given impetus to research to isolate the factors that differentiate human response to noise. The present thesis continues this research. The thesis specifies human noise response to occur on three levels: awareness, annoyance, and complaint. The factors that structure each level of noise response are identified in the published Iiterature. Noise awareness is a function of noise exposure. Noise annoyance is a function of noise exposure to a lesser degree. In addition annoyance is structured by attitudes toward the noise source, special interests in its economic benefits and personal susceptibility to noise irritation. Complaint concerning noise involves the previous factors plus an affluence or socio-economic component. The trend as one moves upward in the noise response hierarchy is for the structuring factors to become specific to individuals rather than location. Hence, noise awareness with respect to a stationary noise source will vary spatially, while complaint will be random in space. In testing these premises the author has made use of noise exposure indices for Portland International Airport and a social survey of response in the area surrounding the airport. The noise exposure indices were supplied by the consulting firm of Bolt, Beranek, and Newman Inc. and the social survey was conducted and tabulated by the Center for Population Research and Census at Portland State University. Multivariate methods were used for testing the premises concerning the hierarchical relationships between awareness, annoyance, and complaint.The variables representing awareness, annoyance, and complaint are quantified from the survey data through principle component and factor scores computer programs. The noise awareness measure is selected for greatest emphasis since it underlies to annoyance and complaint. The noise awareness measure is investigated and errors in its measurement are estimated through psychometric methods. Trend surface techniques are used to test the spatial regularity of awareness, annoyance, and complaint. As hypothesized, awareness is regular in space, annoyance less so, and complaint is random. Through multiple regression analysis noise awareness is tested against socio-economic measures, noise exposure measures, attitudes, and special interest. Noise exposure variables account for the largest part of the variation in noise awareness. A trend surface analysis is conducted on the values of awareness predicted by a large number of exposure, attitude, and other variables. The process is repeated for the residual values from the multiple regression. Predicted values are systematic in space but the residual values are largely random. The predicted values are mapped and compared with the actual smoothed awareness response surface. The two maps correspond well. It is concluded that noise exposure corrected for ambient noise levels adequately approximates the noise awareness response surface.
97

Climatic and Spatial Variations of Mount Rainier's Glaciers for the Last 12,000 Years

Hekkers, Michael Leslie 01 January 2010 (has links)
Regional paleoclimatic proxies and current local climate variables and were analyzed to reconstruct paleoglaciers in an effort to assess glacier change On Mount Rainier. Despite the dry and generally warm conditions (sea surface temperatures (SST) -0.15°C to +1.8°C relative to current temperatures), the previously documented McNeeley II advance (10,900 - 9,950 cal yr B.P.) was likely produced by air temperature fluctuations. The average SST record and the terrestrial climate proxies show cooling temperatures with continued dryness between McNeeley II and the Burroughs Mountain advance (3,442 - 2,153 cal yr B.P.). The paleoclimate during the Burroughs Mountain advance was both cool and warm (SST temperatures -0.55°C to +0.5°C) and was the wettest of the Holocene. A combination of statistical and deterministic equilibrium line altitude (ELA) models was used to produce Holocene ELAs between 1,735 -2,980 m. Glacial advances were predicted 10,990, 10,170, 9,260, 8,200, 6,490, 3,450 and 550 - 160 cal yr. B.P. Two glacier flow models were produced simultaneously to constrain glacial extent through the Holocene. Model I is based on current mass balance parameters and produced lengths for the Nisqually and Emmons glaciers 3.7 - 14.2 km and 4.2 - 17.1 km respectively. Glaciated area ranged from 26 to 327 km2. Model 2 is tuned to the Garda advance and produced lengths 2.6-10.6 km and 2.3-13.9 km. Glaciated area ranged from 11 to 303 km2. The first two advances were similar in elevation and GIS-modeled extent to McNeely II moraines. The following three advances were not detected in the geologic record. The 3,450 cal yr. B.P. advance was the largest of the late-Holocene (ELA 1,800 - 1,817 m) and was ~200 m lower than the geologic record. The ELAs of the Garda advance were modeled (1,944 - 1,983 m) and are similar to previous reconstructions. North-south spatial variations in glacial extent increase during periods of recession as the southern glaciers receive more ablation than northern glaciers. Early humans could have accessed the alpine environments as high as 1,730-2,980 m. The early Holocene glacial extent allowed the highest (2,980 m) 11,150 cal yr. B.P. and lowest (1,730 m) 10,990 cal yr. B.P. alpine access. Glacial retreat (2,727 m 10,400 cal yr. B.P.) was followed by an advance (1,929 m 10,170 cal yr. B.P.) and another retreat (2,951 m 10,050 cal yr. B.P.). Ice gradually descended and limited access to 1,820 m 6,490 cal yr. B.P. Glacial extents remained largely unchanged until the historic era when paleohumans would have had access to alpine environments at 2,000 m.
98

Characterizing Temperature Variability States Across Southern South America and Associated Synoptic-Scale Meteorological Patterns

Detzer, Judah Adam 04 December 2018 (has links)
The aim of this thesis is to understand spatiotemporal temperature variability in southern South America by identifying overarching temperature variability states and their associated synoptic-scale meteorological patterns. Further, the temporal frequency of occurrence of those temperature variability states is investigated as is the role of recurrent low-frequency modes of climate variability (El Niño Southern Oscillation and the Southern Annular Mode) on temperature variability. K-means cluster analysis is used to group all months during the period 1980-2015 into four primary categories for summer and winter separately. Monthly maps of temperature anomalies are provided as input to the k-means algorithm and the resulting temperature variability states are the composites of temperature anomaly maps for months assigned to each cluster, illustrating the primary spatial patterns of temperature variability over Southern South America. Composites of synoptic-scale meteorological patterns (wind, geopotential height, and moisture fields) are calculated for months assigned to each cluster to better diagnose the driving meteorology associated with these patterns of temperature variability. Results show that in summer surface wind direction and geopotential height are robust indicators of temperature variability patterns, while in winter jet stream winds are important for diagnosing equatorward excursions of cold air and poleward excursions of warm air. According to the results the El Niño Southern Oscillation and the Southern Annular Mode exhibit some relationship with temperature variability state frequency, with some states more associated with these two modes than others, however they do not appear to be primary drivers of any of the temperature variability states.
99

The Influence of the Projected Coordinate System on Animal Home Range Estimation Area

Barr, Michael 04 November 2014 (has links)
Animal home range estimations are important for conservation planning and protecting the habitat of threatened species. The accuracy of home range calculations is influenced by the map projection chosen in a geographic information system (GIS) for data analysis. Different methods of projection will distort spatial data in different ways, so it is important to choose a projection that meets the needs of the research. The large number of projections in use today and the lack of distortion comparison between the various types make selecting the most appropriate projection a difficult decision. The purpose of this study is to quantify and compare the amount of area distortion in animal home range estimations when projected into a number of projected coordinate systems in order to understand how the chosen projection influences analysis. The objectives of this research are accomplished by analyzing the tracking data of four species from different regions in North and South America. The home range of each individual from the four species datasets is calculated using the Characteristic Hull Polygon method for home range estimation and then projected into eight projected coordinate systems of various scales and projection type, including equal area, conformal, equidistant, and compromise projections. A continental Albers Equal Area projection is then used as a baseline area for the calculation of a distortion measurement ratio and magnitude of distortion statistic. The distortion measurement ratio and magnitude calculations provide a measurement of the quantity of area distortion caused by a projection. Results show the amount distortion associated with each type of projection method and how the amount of distortion changes for a projection based on geographic location. These findings show how the choice of map projection can have a large influence on data analysis and illustrate the importance of using an appropriate PCS for the needs of a given study. Distorted perceptions can influence decision-making, so it is important to recognize how a map projection can influence the analysis and interpretation of spatial data.
100

A Vegetation History from Emerald Pond, Great Abaco Island, The Bahamas, Based on Pollen Analysis

Slayton, Ian Arthur 01 August 2010 (has links)
Emerald Pond (26° 32' 12" N, 77° 06' 32" W) is a vertical-walled solution hole in the pine rocklands of Great Abaco Island, The Bahamas. In 2006, Sally Horn, Ken Orvis, and students recovered an 8.7 m-long sediment core from the center of the pond using a Colinvaux-Vohnout locking piston corer. AMS radiocarbon dates on macrofossils are in stratigraphic order and indicate that the sequence extends to ca. 8400 cal yr BP. Basal deposits consist of aeolian sands topped by a soil and then pond sediment, suggesting that the site began as a sheltered, dry hole during a Late Pleistocene low sea level stand, and became moister as climate changed and rising sea level pushed up the freshwater table. The limestone rockland surrounding the site is presently dominated by Bahamian pine (Pinus caribaea Morelet var. bahamensis (Griseb.) W.H. Barrett & Golfari) with an understory of hardwoods and several palm species. Pollen analyses on the sediments of Emerald Pond indicate significant environmental change at the site. Pines and palms have dominated for much of the record, with some variation in relative importance. Pine pollen shows a non-uniform, general increase over the record, with highest values reached in a section of the upper meter of the record that contains abundant microscopic charcoal that may be related to anthropogenic activities. Palm pollen is well represented in all but this upper section of the core. The shifts in pollen percentages in the upper meter of the core suggest a generally drier environment during the last two millennia at Emerald Pond.

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