• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 20
  • Tagged with
  • 126
  • 126
  • 126
  • 43
  • 22
  • 21
  • 21
  • 20
  • 20
  • 18
  • 18
  • 18
  • 18
  • 18
  • 17
  • 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.
81

Holocene Fluctuations of the Coe Glacier, Mount Hood, Oregon

Lillquist, Karl Douglas 01 January 1988 (has links)
Numerous moraines front the Coe Glacier on the north side of Mount Hood, Oregon. These moraines were identified and dated using a multiple methodology approach in order to establish a chronology for the advances and stillstands of the Cae Glacier. This chronology was compared to chronologies established for other glaciers on Mount Hood, North Sister, Mount Rainier and Mount Baker as well as glaciers in Scandinavia. The chronology was also compared to a long term temperature record from Longmire, Washington. The maximum identified extent of the pre-Little Ice Age Coe Glacier was indicated by moraines located at an elevation of about 1530 m and about 2 km downvalley of the present terminus. A general period of shrinkage of the pre-Little Ice Age Coe Glacier followed resulting in the deposition of moraines upvalley of the older pre-Little Ice Age moraines. The Little Ice Age Coe Glacier reached its maximum downvalley extent of about 1650 m elevation prior to 1731 AD. An earlier advance (1607 AD) was more extensive laterally than the 1731 AD advance. The Coe Glacier has been in a general state of recession since the mid to late 1700's. The prominent lateral moraines formed prior to 1882 AD. Four low moraines located within the Coe Glacier trough formed before 1901. Historical records indicate that the Coe Glacier has generally continued to recede since then. A comparison of the moraine ages and the historical activity of the Coe Glacier to other glaciers on Mount Hood as well as others in the Pacific Northwest and Scandinavia reveals that fluctuations of the glacier termini are generally synchronous. This similarity, combined with the similarity of the ages of Coe Glacier moraines to cool periods in a long term temperature record, indicates that hemispheric climatic patterns have played a major role in the past fluctuations of the Coe Glacier.
82

The Effects of a Political Boundary Running Through a Metropolitan Area: A Case Study of the Establishment and Functioning of the Jantzen Beach Shopping Center

Reed, Rose Romaine 01 January 1977 (has links)
Jantzen Beach Shopping Center is an anomaly on the landscape challenging traditional criteria for the location of regional shopping centers. Located on Hayden Island on the Oregon side of the border, it has access from only one exit in each direction off the Interstate 5 freeway. The predominantly industrial and recreational land use of the region within a five minute travel time from the shopping center results in an exceptionally small adjacent residential population. Its potential trade area is further limited by the intervening shopping opportunity for Washington residents afforded by the Vancouver central business district which lies adjacent to the Interstate freeway two miles to the north. Interviews established that because of the uneven economic growth within the SMSA, the shopping center was located on the Oregon side of the border due to Portland’s larger population and the propensity for Clark County residents to shop in Oregon to avoid sales tax.
83

Beyul Khumbu: Sherpa Constructions of a Sacred Landscape

Skog, Lindsay Ann 01 January 2010 (has links)
Khumbu, part of Sagarmatha (Mt. Everest) National Park in eastern Nepal and an UNESCO World Heritage site, is home to the Sherpa people, ethnic Tibetan Buddhists who migrated to the region more than 500 years ago. Sherpas animate the landscape with localized water, tree, rock, and land spirits, identify sacred mountains, mainly associated with the Bönpo and Tibetan yullha traditions, and some view the landscape as a beyul, a sacred place and hidden valley protecting Buddhist people and beliefs in times of turmoil and need. These beliefs protect the natural environment through religious practices and taboos against environmentally harmful behaviors and activities. Associated ritual practice, perceptions, and mythology encode Sherpa culture and beliefs in the landscape. This research contributes to discussions of place, sacred landscapes, and conservation by documenting older Sherpa residents’ constructions of Khumbu as a sacred landscape in two Khumbu villages. Interviews and participant observations reveal a socially constructed sacred landscape expressing a distinct Khumbu Sherpa identity.
84

Comparing Twenty-Four Years of Forest Change in Two Communities of Mexico's Meseta Purépecha Using Multi-Spectral Satellite Imagery

Martin, Kevin Scott 03 June 2004 (has links)
The Meseta Purepecha, a volcanic plateau in the Mexican state of Michoacan, is home to one of the most species-rich pine forests in the world. Recent increases in demand for forest products has put added pressure on these resources. Though existing research has suggested significant deforestation in the Meseta, there is little information identifying specific areas of decline. This study focuses on two indigenous communities in the Meseta-Pichataro and Sevina. Both communities have long relied on wood as an economic resource. However, the two communities have reacted differently to increased demand for forest resources. The purpose of this study is to identify the differences in the rate and extent of forest change between Pichataro and Sevina. Three dates of Landsat satellite images - 1976, 1986, and 2000-were used to identify changes in the Meseta's forests. Supervised classification was used to classify the 2000 image into forested and non-forested areas. Change detection was performed on the 1976 through 2000 images to identify areas of forest clearing and forest regrowth. The 2000 image was then used as a reference for generating maps of historic forest extent based on the change detection results. Results show that between 1986 and 2000, Sevina cleared approximately 16% of its forested land between while Pichataro experienced a net gain of 7%. In the same period, 93% of the deforestation in the combined study area occurred within the community boundary of Sevina, which manages only 35% of the study area forests. Sevina's remaining forests are also more isolated and fragmented than the forests of Pichataro. The differences between the two communities appear related to management practices. Sevina has relied on larger-scale timber harvesting to derive economic benefits from its forests. Pichataro has focused on local harvesting and value-added production.
85

Impacts of Sea-Level Rise on Urban Properties in Tampa Due to Climate Change

Xie, Weiwei 10 December 2021 (has links) (PDF)
The fast urbanization produces a large and growing population in coastal areas. However, the rise of sea level, one of the most significant impacts of global warming, makes coastal communities much more vulnerable to flooding than before. This Master’s thesis study investigates sea-level rise impacts on parcel-level property in the specific coastal city of Tampa, Florida, USA. An improved sea-level rise model based on satellite altimeter data is first used to predict future sea levels. Based on high-resolution LiDAR digital elevation data and property map, flooded properties are identified to evaluate property damage cost. This empirical analysis provides an in-depth understanding of potential flooding risks for individual properties with detailed spatial information at a fine spatial scale. The spatial and temporal analyses can be potentially used by researchers or governments to mitigate the impact of sea-level rise and make better urban management plans to adapt to climate change.
86

Eastern Deciduous Forest Phenology and Vegetative Vigor Trends From 2000 to 2013, Mammoth Cave National Park, KY

Hutchison, Sean Taylor 01 December 2013 (has links)
Global climate change is predicted to affect environmental systems at the midlatitudes, but the scope, severity, and outcomes of these impacts are yet to be fully understood. This study focuses on the implications of short-term climate variability for forests in central Kentucky. Using a Normalized Difference Vegetation Index (NDVI) calculated from MODerate-Resolution Imaging Spectroradiometer (MODIS) instrument data, the photosynthetic activity of vegetation at Mammoth Cave National Park (MACA) is tracked from 2000 to 2013. Three methods were employed to examine the changes and climate influences in vegetation over the study period: 1) aggregating the NDVI of the Park by year and by summer months (June, July, and August) and examining how these productivity trends could be influenced by precipitation and temperature fluctuations, 2) examining the trend of the NDVI at selected dates throughout the study period to detect phenological shifts around leaf-out and leaf-off, and 3) using a generalized vegetation classification of MACA to clip the imagery based on areas of similar vegetation and then testing correlations between those subsets and teleconnections. The results from the aggregated NDVI show there is an insignificant negative trend. A negative relationship between summer forest productivity at MACA and temperature was found, though more data are needed to rigorously validate this result. Changes in phenology indicate forest productivity is decreasing earlier each year throughout the study period. Finally, the Multivariate ENSO Index and the Pacific Decadal Oscillation index are shown to have significant positive correlations with the summer productivity of MACA during the study period.
87

Spatial Analysis of Post-Hurricane Katrina Thermal Pattern and Intensity in Greater New Orleans: Implications for Urban Heat Island Research

Lief, Aram P 16 May 2014 (has links)
In 2005, Hurricane Katrina’s diverse impacts on the Greater New Orleans area included damaged and destroyed trees, and other despoiled vegetation, which also increased the exposure of artificial and bare surfaces, known factors that contribute to the climatic phenomenon known as the urban heat island (UHI). This is an investigation of UHI in the aftermath of Hurricane Katrina, which entails the analysis of pre and post-hurricane Katrina thermal imagery of the study area, including changes to surface heat patterns and vegetative cover. Imagery from Landsat TM was used to show changes to the pattern and intensity of the UHI effect, caused by an extreme weather event. Using remote sensing visualization methods, field data, and local knowledge, the author found there was a measurable change in the pattern and intensity of the New Orleans UHI effect, as well as concomitant changes to vegetative land cover. This finding may be relevant for urban planners and citizens, especially in the context of recovery from a large-scale disaster of a coastal city, regarding future weather events, and other natural and human impacts.
88

Logging in the Upper Cumberland River Valley: A Folk Industry

Schulman, Steven 01 May 1973 (has links)
The purpose of this study is to examine the logging industry found along, the upper Cumberland River from the 1870s to the 1930s. Because the industry was very much a part of the economic lifeblood of the people of the region, the study will focus upon the loggers and raftsmen who worked with the timber. Any attempt to describe the lumber business alone would be futile due to the nature of the industry. It is impossible to separate the logging industry of the Cumberland from the general folk life of the area, because of the involvement of the people in the business. This study then is as much a description of the folk life of the Cumberland River Valley as it is a consideration of the logging industry.
89

MIDDLE TO LATE HOLOCENE (7200-2900 CAL. BP) ARCHAEOLOGICAL SITE FORMATION PROCESSES AT CRUMPS SINK AND THE ORIGINS OF ANTHROPOGENIC ENVIRONMENTS IN CENTRAL KENTUCKY, USA

Carlson, Justin Nels 01 January 2019 (has links)
Though some researchers have argued that the Big Barrens grasslands of Kentucky were the product of anthropogenic land clearing practices by Native Americans, heretofore, this hypothesis had not been tested archaeologically. More work was needed to refine chronologies of fire activity in the region, determine the extent to which humans played a role in the process, and integrate these findings with the paleoenvironmental and archaeological record. With these goals in mind, I conducted archaeological and geoarchaeological investigations at Crumps Sink in the Sinkhole Plain of Kentucky. The archaeological record and site formation history of Crumps Sink were compared with environmental and archaeological data from the Interior Low Plateaus and Southern Appalachian Mountains for an understanding of how the site fits into the larger story of human-environmental interactions in the Eastern Woodlands. Based on the data recovered, I argue that through land burning Archaic hunter-gatherers were active managers of ecosystems to a greater degree than previously acknowledged. Excavations at Crumps Sink revealed stratified archaeological deposits spanning the late Middle Archaic to Terminal Late Archaic periods. Radiocarbon dates and an analysis of projectile point typologies provided information on the chronological and cultural history of the site. Magnetic susceptibility, loss-on-ignition, plant available phosphorous, and soil micromorphological analyses were conducted to examine landform dynamics in response to environmental change and to trace the anthropogenic signature created by human activities at the site. Masses of lithic debitage, animal bone, and burned sediment nodules per ten-cm-level provide an indication of human occupation intensity and shifting activities over time. Radiocarbon dates were used to reconstruct rates of sediment accumulation in the sink. These varying datasets were considered together for a holistic understanding of localized environmental and anthropogenic impacts on the landform. Between 7200 and 5600 cal. BP, during the Middle Holocene Thermal Maximum and corresponding with the late Middle Archaic period, sediment accumulation was sustained with one identifiable episode of very weak soil development. Background magnetic and chemical signatures in the soils were greater than they were at pre-occupation levels, demonstrating that human activities left a lasting imprint in soils as early as the late Middle Archaic period. Between 5600 and 3900 cal. BP, periods of diminished sedimentation led to more pronounced episodes of soil formation. However, these soil horizons are interposed by pulses of enhanced sediment accumulation. These soil data may signal shifting environmental regimes during the Middle to Late Holocene transition. Between 5600 and 3900 cal. BP scattered plant ash, elevated masses of burned sediment nodules, and pestle fragments in Late Archaic deposits suggest that hunter-gatherers were intensively processing nut mast, potentially in association with early forest clearance and silviculture. Botanical assemblages from a coincident archaeological sequence at the Carlston Annis site in the nearby middle Green River region has demonstrated woodland disturbance and potential silviculture in central Kentucky during this time. During the Late Archaic and Terminal Late Archaic periods (3900-3000 cal. BP), substantial plant ash deposition occurred in a stratum that accumulated relatively quickly. Very low burned sediment nodule masses in this deposit indicate that combustion features were not common in the immediate vicinity and that elevated frequencies of plant ash were the result of burning on a broader expanse of the surrounding landform. Chronologically, the zone with enhanced plant ash deposition is coeval with previously demonstrated occurrences of increased forest fires, grassland expansion, and a shift to early horticultural economies throughout the region. Soil development occurred after 3000 cal. BP, and this episode of landform stability may have lasted for over two millennia until being capped by sediment accumulation from historic agriculture. The late Middle Archaic through Terminal Late Archaic data from Crumps Sink demonstrate that hunter-gatherer activities left lasting signatures in soils in Kentucky. The data from the Late Archaic to Terminal Late Archaic periods (ca. 5600-3000 cal. BP) may indicate intentional land burning by hunter-gatherers to create anthropogenic environments, first for silviculture and then for early plant domestication. This forces a rethinking of labor and subsistence systems within hunter-gatherer societies. Thus, if hunter-gatherers were utilizing long-term forest management methods, they were employing a delayed-return economic system relying on labor investment and negotiated understandings about land tenure. Further characterization of the origin of fire management activities will help us to elucidate the nature of incipient indigenous plant domestication in the Eastern Woodlands.
90

ACCOUNTING FOR SPATIAL AUTOCORRELATION IN MODELING THE DISTRIBUTION OF WATER QUALITY VARIABLES

Miralha, Lorrayne 01 January 2018 (has links)
Several studies in hydrology have reported differences in outcomes between models in which spatial autocorrelation (SAC) is accounted for and those in which SAC is not. However, the capacity to predict the magnitude of such differences is still ambiguous. In this thesis, I hypothesized that SAC, inherently possessed by a response variable, influences spatial modeling outcomes. I selected ten watersheds in the USA and analyzed them to determine whether water quality variables with higher Moran’s I values undergo greater increases in the coefficient of determination (R²) and greater decreases in residual SAC (rSAC) after spatial modeling. I compared non-spatial ordinary least squares to two spatial regression approaches, namely, spatial lag and error models. The predictors were the principal components of topographic, land cover, and soil group variables. The results revealed that water quality variables with higher inherent SAC showed more substantial increases in R² and decreases in rSAC after performing spatial regressions. In this study, I found a generally linear relationship between the spatial model outcomes (R² and rSAC) and the degree of SAC in each water quality variable. I suggest that the inherent level of SAC in response variables can predict improvements in models before spatial regression is performed. The benefits of this study go beyond modeling selection and performance, it has the potential to uncover hydrologic connectivity patterns that can serve as insights to water quality managers and policy makers.

Page generated in 0.0872 seconds