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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.
1

Improving Rangeland Seedling Recruitment Using Fungicide Seed Coatings and Golden Eagle Reproductive Success in Relation to Explosive Military Tests and Trainings

Hoose, Benjamin William 30 November 2020 (has links)
The objective of the first chapter of this thesis was to determine whether fungicide seed coatings constitute an effective strategy for increasing seedling recruitment in restoration scenarios in the Intermountain West. We tested a mixture of four fungicides that address potential fungal pathogens to bluebunch wheatgrass, a dominant bunchgrass that is commonly used in restoration. Across two sites and three years, we found that the fungicide seed coating increased emergence in five of the six sites and years, with an average increase of 59.1% over the control. There was a strong interaction (P < 0.001) between the effects of fungicide treatment, the year and the site on emergence. This interaction was likely related to the effects of the hydrothermal microsite environment on disease severity. Further research is necessary to fully understand the conditions under which fungicide seed coatings are most likely to be effective. The objectives the second chapter of this thesis were to 1) estimate the effects of golden eagle nest proximity to explosive disturbances on reproductive success given other relevant habitat variables (e.g. indices of topography and vegetation), and 2) determine the relative importance of nest proximity to explosive disturbances as a predictor of golden eagle reproductive success compared to other relevant habitat variables. Reproductive success data were collected from nesting territories within and surrounding land controlled and managed by the US Department of Defense. We fit the reproductive survey data using generalized linear mixed-effects models comprised of unique, hypothesis-based sets of habitat variables. We compared the models using AICc-based model selection processes. Given the best approximating model, we found no evidence that the likelihood of reproductive success was affected by nest proximity to explosive disturbances (P = 0.460). We further found nest proximity to explosive disturbances consistently ranked in the bottom 50% of relative variable importance. These results may indicate golden eagle tolerance or habituation to explosive military tests and trainings. Although the two chapters of this thesis are disjointed, they are loosely unified by the ecological importance of disturbance, invasive species, and restoration within the Great Basin ecoregion.
2

Use of Seed Coating Technologies to Improve Cercocarpus ledifolius (Curl-Leaf Mountain Mahogany) Seed Germination and Emergence to Reclaim Mine Lands

Nielson, Emily M. 04 August 2022 (has links)
Globally, mining is vital to human interests, but its practice can cause landscape alteration which may look unnatural or engineered. The reintroduction of native plants to these areas is needed to restore the visual appeal and ecological function back into these altered mine lands. Cercocarpus ledifolius (curl-leaf mountain mahogany) is one desirable native species in the Intermountain West that is prized for its potential to grow on step and rocky hillsides and for the habitat it provides for wildlife. Unfortunately, C. ledifolius does not establish well from seed, which has been attributed to seed dormancy. The first objective of this study was to determine if scarification and gibberellic acid (GA3) treatments improve germination by alleviating seed dormancy. We also aimed to determine if a combination of fungicide and hydrophobic seed coatings increased emergence and establishment of C. ledifolius seedlings in mine overburden by reducing loss from fungal pathogens and premature germination. We found that two treatments, GA3 and GA3 + hydrophobic coatings, improved emergence compared to untreated seed, producing 1.8 (P = 0.0682), and 2.2 (P = 0.0751) more seedlings per meter, respectively. The second objective of this study was to make improvements in the laboratory to treatments explored in the field trial. We found that C. ledifolius seed responded inconsistently to treatments applied in the lab. The 15-minute acid scarified seed in combination with various GA3 seed coatings had significantly higher germination than untreated seed in one trial but had no difference in a second trial. Overall, these results indicate that seed enhancement technologies have the potential to improve C. ledifolius emergence in reclaimed mine lands, but additional research is needed to understand the species' dormancy characteristics better and improve the efficacy of the applied seed treatments.
3

Improving Post-Wildfire Seeding Success using Germination Modeling and Seed Enhancement Technologies

Richardson, William Charles 01 April 2018 (has links)
Arid and semi-arid rangelands are important ecosystems that are consistently degraded through disturbances such as wildfires. After such disturbances, the invasion and dominance of annual grasses, like cheatgrass (Bromus tectorum L.), can lead to an overall loss of ecosystem productivity and an increase in fire frequency. To reduce weed dominance, native and introduced perennials species are typically be seeded in the fall. High mortality is seen from these seeded plant communities due to germinated seed being exposed to freezing, drought, fungal pathogens, and other biotic and abiotic stressors during winter months. We utilized wet-thermal accumulation models to first further validate the theory that germination from seeded plant populations occurs during periods of high environmental stress, and then to establish the practicality of abscisic acid seed coatings as a technology that could circumvent winter germination and mortality. In Chapter 1, we developed an excel workbook called Auto-Germ using Visual Basic for Applications, which allows users to estimate field germination timing based on wet-thermal accumulation models and field data. We then used Auto-Germ to model seed germination timing for 10 different species, across 6 years, and 10 Artemisia-steppe sites in the Great Basin of North America. We estimated that for the majority of the species analyzed, a mid to late-winter planting was required on average for the majority of the population to germinate in the spring. This planting time would be logistically difficult for many land managers, due to freezing and/or saturated soil conditions. In Chapter 2, we utilized wet-thermal accumulation models to evaluate the use of abscisic acid (ABA) to delay germination of Pseudoroegneria spicata (Pursh) Á. Löve (perennial native bunchgrass) across 4 years and 6 Artemisia-steppe sites. Germination models estimated that ABA seed treatments typically would delay germination of fall sown seed to late winter or early spring when conditions may be more favorable for plant establishment. Based on these results, we recommend both the use of wetthermal accumulation models as a tool in educating researchers and land managers in knowing when seeding practices should occur, and the further study of ABA seed coatings as a technology that may improve plant establishment of fall sown seeds.
4

Disciplinary Mythologies: A Rhetorical-Cultural Analysis of Performance Enhancement Technologies in Sports

Lamothe, John 01 January 2015 (has links)
In sports discourse, the relationship between athletics and technology is often paradoxical. On the one hand, modern sports rely on technology at every level, from training and tracking of players to the equipment and apparel used by athletes to the game strategies and playing fields themselves. Nearly all of these technologies are intended to increase athletic performance on some level. And yet, certain performance enhancement technologies can be criticized for being antithetical to the spirit of sports, which is framed as being a strictly natural and pure human endeavor. Using a rhetorical-cultural methodological approach, popular sports discourse is analyzed to investigate how arguments in contested spaces between sports and technologies get (re)negotiated and (re)articulated to fit within a sports social language that emphasizes "pure" and "natural" ideals of sport. This often results in a dichotomy where the sport/technology relationship is either black boxed, thus being subsumed in the sport social language and becoming transparent and the relationships unarticulated, or the technology is regulated out of the sport through rules and bans. The reason for this articulation is attributed in large part to the deep humanism embedded in the sport social language. How a shift to a posthuman perspective would effect sports discourse is explored. These conclusions about underlying values in sports discourse lead to the formation of a new theoretical framework called disciplinary mythologies. Building off of Foucault's disciplinary power, Scott's disciplinary rhetorics, and Barthe's mythologies, disciplinary mythologies are discrete units of persuasion that both construct and constitute claims by drawing upon layered narratives and shifting associations that lose their context when entering the realm of myth. Two specific disciplinary mythologies are discussed—the level-playing-field topos and the nostalgia enthymeme—and it is shown how sports discourse often draws upon them to shape arguments and actions.
5

Transcendence: An Ethical Analysis of Enhancement Technologies

McCormick, Sean Eli 27 May 2016 (has links)
No description available.

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