• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5551
  • 2354
  • 1627
  • 1016
  • 440
  • 440
  • 440
  • 440
  • 440
  • 439
  • 391
  • 389
  • 386
  • 371
  • 367
  • Tagged with
  • 15282
  • 2720
  • 2501
  • 2339
  • 2211
  • 1885
  • 1495
  • 1340
  • 1053
  • 1002
  • 972
  • 900
  • 874
  • 732
  • 696
  • 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.
61

Rock Glacier Distribution, Activity and Movement, Northern Absaroka and Beartooth Ranges, MT, USA

Seligman, Zachary M 15 June 2009 (has links)
Rock glaciers of the northern Absaroka and Beartooth Ranges have not previously been described. Six-hundred and sixty rock glaciers were hand digitized in a GIS and evaluated using 11 distributional characteristics. Beartooth rock glaciers were found to occur at higher elevations, receive more precipitation, and were subjected to colder temperatures. Additionally, logistic regression analysis was used to examine the predictive strength of the 11 descriptive parameters on rock-glacier activity. Elevation and average annual maximum temperatures were most strongly correlated with activity. Results were used to make inferences about permafrost distribution which coincided with estimates from previous studies. Finally, movement rates of four rock glaciers within the Black Canyon Basin of the Beartooth Mountains were estimated using photogrammetric techniques over a 51-year period. While movement rates were consistent with those determined in other Rocky Mountain locations, much of the results were inconclusive. Increased movement of the East Grasshopper rock glacier may be the result of increased glacier subsidence, while uphill movement of the Beartooth rock glacier may be indicative of rock-glacier subsidence.
62

Glacier Monitoring in Ladakh and Zanskar, northwestern India

Byrne, Martin Edward 16 June 2009 (has links)
Glaciers in the Himalaya are often heavily covered with supraglacial debris, making them difficult to study with remotely-sensed imagery alone. Various methods such as band ratios can be used effectively to map clean-ice glaciers; however, a thicker layer of debris often makes it impossible to distinguish between supraglacial debris and the surrounding terrain. Previously, a morphometric approach employing an ASTER-derived digital elevation model (DEM) has been used to map glaciers in the Khumbu Himal and the Tien Shan. This project aims first to test the ability of the morphometric procedure to map small glaciers; second, to use the morphometric approach to map glaciers in Ladakh; and third, to use Landsat and ASTER data and GPS and field measurements to monitor glacier change in Ladakh over the past four decades. Field work was carried out in the summers of 2007 and 2008. For clean ice, a ratio of shortwave infrared (SWIR, 1.6-1.7 µm) and near infrared (NIR, 0.76-0.86 µm) bands from the ASTER dataset was used to distinguish snow and ice. For debris-covered glaciers, morphometric features such as slope, derived from a DEM, were combined with thermal imagery and supervised classifiers to map glacial margins. The method is promising for large glaciers, although problems occurred in the distal and lateral parts and in the forefield of the glaciers. The morphometric approach was inadequate for mapping small glaciers, due to a paucity of unique topographic features on the glaciers which can be used to distinguish them from the surrounding terrain. A multi-temporal analysis of three glaciers in Ladakh found that two of them have recededone since at least the mid-1970s, the other since at least 2000while a third glacier, Parkachik Glacier, seemed to have retreated in the 1980s, only to advance in the 1990s and early 2000s. However, from 2004-2008 it showed only negligible change making its current status difficult to determine without further monitoring. The glacier outlines derived during this project will be added to the Global Land Ice Measurements from Space (GLIMS) database. In testing the limits of the morphometric approach, the thesis has provided a valuable contribution to the present literature and knowledge-base regarding the mapping of debris-covered glaciers.
63

Assessing Accessible Transportation Options Using GIS in Missoula, MT

Jurica, Jillian Jo 16 July 2009 (has links)
Accessible transportation is an integral service for many people with disabilities and the elderly in order to live healthy and fulfilling lives. This thesis aims to give communities a way of assessing their accessible transportation services to determine if they are adequately providing transportation to these populations. In this project data was gathered through interviews with agencies that provide accessible transportation in Missoula, MT and the surrounding area. This data in conjunction with U.S. Census data was compiled and spatially analyzed using GIS to create maps to assess current accessible transportation and show where additional accessible transportation may be of value. The maps created illustrate the number of options available for locations across the study area and when accessible transportation is available. The maps show that there is variance in the number of options across the study area and that as one moves toward the outskirts of the Missoula area, accessible transportation options are very limited. Additional maps spatially display factors associated with transportation such as cost, purpose for which the transportation can be used, eligibility criteria for the services, and type of additional assistance provided to the rider. These maps indicate there is variance in these factors across the study area also. This indicates that potential users may not have access to the most suitable transportation option depending on where they need to be picked up and dropped off. A second interview was conducted to ascertain the accuracy of the maps and if the agency representatives believe this information can be used to coordinate and collaborate services with each other and help them determine how to expand or restructure services. Four out of five of the agency representatives that participated in the study believe the maps provided useful information to their agency and all agencies agreed that this process would be useful to other communities in assessing their accessible transportation.
64

Examining Narratives of Place: Representations of Xinjiang in Tourism and Geography Education

Church, Michael 22 September 2010 (has links)
This thesis examines how Xinjiang Uyghur Autonomous Region, located in northwest China, is represented in tourism and geographic education literature. The research demonstrates the limited and distorted place narratives of Xinjiang that are promoted by the government-backed tourist enterprise in China for consumption by English language speakers; as well as, the inadequate and uncritical representations of the region currently available to students in the United States. Qualitative content analysis methodology is employed to investigate the narrative representations of Xinjiang contained within tourist brochures, geography textbooks, and regionally appropriate curricular guides. The thesis includes a body of geographic lesson plans pertaining to Xinjiang I created that are informed by the research results. The purpose of this thesis is to move toward a more nuanced understanding of Xinjiang as a dynamic region of global significance, challenge prevailing stereotypes of the region, and strengthen geography literacy, particularly among school aged students.
65

DAM REGULATIONS EFFECTS ON SAND BAR MIGRATION ON THE MISSOURI RIVER: SOUTHEASTERN SOUTH DAKOTA

Sanford, John Perkins 18 January 2008 (has links)
upload later
66

Food Supply Chains and Food-Miles: An Analysis for Selected Conventional, Non-local Organic and Other-Alternative Foods Sold in Missoula, Montana

Spielman, Kimberly 18 January 2008 (has links)
The spatial patterns of the conventional food supply chain have played a significant role in increasing the amount of miles food travels before being consumed. As a result, this has increased the amount of energy that is required to transport food from the farm to the table. The food supply chain links production to consumption. However, as food-miles increase, this link becomes obscure. The food supply chain can be described as having two very distinct parts: the conventional food supply chain and the alternative food supply chain. Business consolidation, and large-scale production, processing, distribution and retail characterize the conventional food supply chain. As a result of such economies of scale, the conventional chain is also characterized by standardization of knowledge. The alternative chain, on the other hand, is characterized by direct sales, small-scale production, processing and distribution and by a more transparent market. Certified organic foods began as an alternative to conventional foods. However, certified organic foods have increasingly been criticized for adopting similar business practices as the conventional system and thus travel the same lengths, if not further, than conventional foods. This study is a place-based approach that compares the food-miles and subsequent energy use of the two food supply chainsconventional and alternativethat provide food to retail grocery stores in Missoula, Montana. Energy use is estimated in gallons of diesel and the subsequent byproduct, or emissions, of transportation is estimated in pounds of carbon dioxide. Four of the highest selling retail grocery products; apples, bread, ground beef and milk, are classified into three different categories: conventional, non-local organic and other-alternative. The food-miles, subsequent fuel usage and emissions are also estimated for each of the four products. The study shows a remarkable lack of transparency in the conventional food supply chain and relatively low food-miles, fuel use and carbon dioxide emissions for the other-alternative products.
67

Estimating Potential Economic Net Carbon Flux from U.S. Agriculture Using a High Resolution, Integrated, Socioeconomic-Biogeophysical Model

Hellwinckel, Chad M. 01 August 2008 (has links)
Estimation of the carbon abatement potential of a national carbon market upon U.S. agricultural lands is needed by climate analysts, policymakers, and carbon market brokers. A high resolution, integrated, socioeconomic-biogeophysical model is developed in this research by linking the economics of land management with spatial data on soils and land use. The economic component of the model functions at the county level with biophysical data at the sub-county level of resolution. The model is used to estimate changes in net carbon flux induced by incentives for conservation tillage on nine major crops. The economic potential reduction in net carbon flux at incentives of $500 per metric ton carbon (MtC) is estimated to be 18.92 million metric tons carbon (MMtC) below baseline, and 12.6 MMtC below baseline at an offered incentive of $125 per MtC. Results indicate that the Northern Great Plains, northern Corn Belt, and Mississippi Delta have the greatest economic potential for carbon abatement. Regions with significant amounts of acreage in hay have the greatest potential for gains in net soil carbon. Application of incentives based on soil sequestration potential leads to “leakage” in some regions where land is reallocated from low input practices to higher input practices. This analysis created an ideal opportunity to study the interactions of data resolution and analytical scale. When analyzing carbon abatement at the national scale, abatement estimations were similar using either high or low resolution data. But, if regional estimation is a goal, the geographic resolution of data must match or surpass the geographic scale of analysis, otherwise estimation errors will be large. Although validation using field-level data indicates that model results are not appropriate for fieldlevel estimation, it also indicates that the high resolution methodology developed here results in much smaller errors than lower resolution versions. Results indicate that there are many challenges to implementation, but if policymakers decide to implement a carbon abatement program using conservation tillage, either through a market-based mechanism or through government ‘green payments’, the methodology developed here could help reduce uncertainty in estimating regional abatement quantities.
68

Spatio-Temporal Patterns of Geomorphic Adjustment in Channelized Tributary Streams of the Lower Hatchie River Basin, West Tennessee

Boulton, Mary A 01 December 2005 (has links)
The processes involved in fluvial geomorphic adjustment to human-induced change are not well understood, despite an increasing and global prevalence of human disturbance to rivers. This doctoral dissertation research examines spatial and temporal patterns of geomorphic adjustment processes in three tributary streams of the Lower Hatchie River Basin, in west Tennessee, which are adjusting to historic land clearance and channelization. This dissertation examines (1) the types and spatial pattern of geomorphic adjustment processes in a total of 34 tributary reaches located in Richland, Jeffers, and Dry Creeks, (2) the applicability of an existing model of geomorphic adjustment for use in tributary streams with multiple episodes of disturbance, (3) sediment dynamics at the reach scale, including floodplain and channel re-coupling, and (4) the connections between reach-scale processes of sediment dynamics and systemwide geomorphic response. Results from this dissertation research suggest that after an initial period of down cutting, channel widening involving bank failure and bank undercutting are the dominant adjustment mechanisms, and create asymmetrically-shaped channels. Bank failures in the study tributaries are common and are produced by progressive bank undercutting related to redirection of flow towards banks by well-developed bars and berms deposited in the channel. The lifetime of channel bars and berms appears to be long, enduring beyond seven months of monitoring. The common occurrence of asymmetric channels and well-developed bar and berm deposits throughout each of the three study tributaries lends field-based support for the operation of bar-bend processes of lateral migration. These results highlight the important role of lateral adjustment processes postchannelization and sediment storage in determining the location of geomorphic processes and potentially initiating system-wide lateral migration. Applicability of the Channel Evolution Model may be liInited in tributary streams with mUltiple periods and/or locations ofchannelization because it focuses on the area of maximum disturbance, and it lacks explicit incorporation of lateral migration processes and sediment dynamics. Field-based sediment monitoring and simulation of sediment connectivity using channel morphometrics and Multi-Response Permutation Procedure suggest that sediment dynamics remain in a state of adjustment, lacking suitable long-term storage of sediment due to floodplain/channel de-coupling and irregular sediment transport. Analysis of a core taken from one re-coupled floodplain in Richland Creek suggests that re-coupling is possible but, in this instance, required more than 50 years to occur. This indicates that sediment will continue to be stored in the channel well into the future, potentially prolonging channel widening and lateral migration processes. Finally, results from this research suggest that spatial and temporal patterns of geomorphic adjustment depend upon reach-scale processes of sediment dynamics and flow deflection. The dominance of reach-scale dynamics in the tributaries calls into question the applicability of numerical models developed on a watershed-based approach and demonstrates the need to understand reach-scale controls ofsystem-wide response in fluvial systems.
69

Canada’s Cultural Media Policy and Newfoundland Music on the Radio: Local Identities and Global Implications

Keough, Sara Beth 01 May 2007 (has links)
As our access to information increases with the aid of communication technologies, there is concern about cultural homogenization. Ironically, however, in the face of globalization in the media, the local often becomes increasingly important. This study explores how Canada’s cultural policy toward the media, known as the Canadian Content regulations, has both local and global implications. I examine how Canadian Content regulations apply to radio, and how these radio regulations influence broadcasting in the St. John’s, Newfoundland radio market. Interviews with radio station personnel (e.g. DJs, program directors, music librarians) and radio listeners show that radio stations in St. John’s emphasize local (Newfoundland) music in the face of more popular Canadian and American music. In addition, this emphasis on local content ensures the survival of these stations in light of new radio broadcasting technologies such as the Internet and satellite radio. Furthermore, the act of broadcasting local music on the radio in St. John's has allowed radio listening to become incorporated into listeners' Newfoundland cultural traditions. In this way, the radio becomes a medium through which station personnel and listeners present their culture by showcasing music and actively preserve their culture through the broadcast of music that speaks of times past, or current issues facing Newfoundlanders. Finally, when talking about their experience listening to Newfoundland music on the radio, several themes emerged: connection between Newfoundlanders and their identity and culture, connections with other Newfoundlanders in Newfoundland, connections to Newfoundland as a place, and connections with Newfoundlanders living off the island. Generally speaking, this study shows that radio technology brings both the local to the global through Internet broadcasting, and the global to the local through satellite radio broadcasting.
70

Crossing the Rubicon: The Demise of Segregation and the Origins of Divergence in South Africa and the American South

Rector, Kyle Thomas 01 May 2008 (has links)
South Africa and the American South have long shared historical and socioeconomic commonalities. Of these similarities, their histories of governmentally-mandated racial segregation are what most often led people to draw comparisons between the two areas. Likewise, South Africa and the American South for much of the 20th century were considered atypical or exceptional when compared to their geographically proximate neighbors. Hence, research by Fredrickson, Cell, Sparks, and others identify how these two areas, though halfway around the globe from one another, have mirrored and impacted one another. With the demise of governmentally-mandated segregation in both areas, it is worth asking whether South Africa and the American South will continue to be similar to one another while being exceptional vis a vis their neighbors or whether this trait will fade. This dissertation uses a mixture of quantitatively-based research focusing on the cities of Bloemfontein, South Africa and Wilmington, North Carolina and more general qualitative analysis for South Africa and the American South to examine patterns of change during the transition from segregation to post-segregation periods in each region. It is argued that the end of segregation in South Africa and the American South may well have irrevocably set them on diverging paths as each becomes increasingly like their geographically proximate neighbors.

Page generated in 0.1105 seconds