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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.
51

Multi-Element Composition of Triglochin Maritima L. from Contrasting Habitats including Hot Springs and Metal Enriched Areas

Sunwar, Sharmila January 2011 (has links)
The aim of this PhD research was to study multi-element composition in wetland plants from contrasting habitats, including hot springs, temporary wetlands, and metal-rich areas. Triglochin maritima L. (seaside arrowgrass) was chosen for the study because this species is common in alkaline/saline soils and is adapted to diverse habitats. Eleocharis rostellata, Juncus balticus, Salix exigua, S. boothii, and S. wolfii were also included in the study. Field studies and greenhouse experiments were conducted to study the multi-element composition in plants. In the greenhouse experiment the effects of temperature and soil biota on multielement uptake in T. maritima were studied. Root-zone soils and plant samples were analyzed for 32 - 50 elements using inductively coupled plasma OES/MS spectrometry. The expected outcomes from this research were: 1) the development of multi-element fingerprints for T. maritima and other plant species from contrasting habitats, and 2) a better understanding of the effects of temperature and soil biota on multi-element uptake in T. maritima. Habitat specific element concentration patterns in T. maritima were observed; concentrations of Mn, Li, and B were high in plants from hot spring influenced wetlands, whereas Ca, P, Mg, Fe, Sr, Ba, Ti, and Cu were higher in the plants of temporary wetlands. J. balticus and Salix species from mine impacted and uncontaminated sites revealed distinct differences in multi-element fingerprints. J. balticus showed high concentrations of S, K, Mn, Fe, Cu, Al, As, and Cd at contaminated sites compared to un-contaminated sites. Multi-element fingerprints of Salix species showed that S. boothii had higher concentrations of Mn, Fe, Al, and Ti compared to S. exigua and S. wolfii. To our knowledge for the first time the association of mycorrhizal fungus in T. maritima was confirmed, and significant effects of temperature on element concentrations, contents, and their translocation in plants were observed. Generally, the distribution of the total contents of P, Na, Mn, B, Cu, Mo, Li, Sr, Ti, and Cs in both roots and leaves were lower at 40 °C compared to 20 and 30 °C, but their distribution and translocation from root to leaves were higher at 40°C. Even though the biological and physiological functions of Li, Sr, Ba, Rb, and Ti in plants are not fully understood, these elements were substantially taken up by T. maritima, and significant positive correlations of these elements were found with elements that have known biological functions. Overall, concentrations of Ca, P, Mg, Mn, B, Sr, and Ba in T. maritima showed variation due to differences in habitats, temperature, and experimental growing conditions (greenhouse and field condition). Concentration patterns of Na, K, and Zn were species specific and affected by temperature. Li concentrations varied due to habitat differences, growth conditions, and species differences. Future research directions could include: 1) identification of the fungal species associated with T. maritima and studies to elucidate their possible role in survival of T. maritima in the elevated temperature of hot springs, 2) the effects of soil factors, such as salinity and 3) seasonal variation in uptake and translocation, particularly for the less studied elements with yet unrecognized but potential biological functions in plants. / NIH Grant Number P20 RR016471 from the INBRE Program of the National Center for Research Resources / North Dakota State University. Department of Biological Sciences / Robert H. Levis II Cross Ranch Fellowship / North Dakota State University. Environmental and Conservation Sciences program
52

Demographic Influences on Attitudes Toward Adolescent Sexuality in a Rural Wyoming County

Dalton, Michael J. 01 May 1997 (has links)
A countywide survey in Uinta County, Wyoming, was conducted from December 1992 through March 1993. A stratified random sampling method was used in which 647 surveys were distributed with an overall response rate of 59.5%. This study employed analysis of variance (ANOVA) to address four research questions contending that the independent variables o f education, socioeconomic status, employment, and family stat us would differentially account for variation in the dependent variables, which were responses to survey items indicating the "appropriate age" to teach children about human reproduction, consequences of sexual activity, birth control methods, HIV/AIDS prevention, and sexually transmitted diseases. The data revealed small, but statistically significant relationships. A positive association existed between higher educational attainment and indication of older appropriate ages to teach children about the consequences of sexual activity and sexually transmitted diseases at school. Respondents with higher incomes specified younger ages to teach children about human reproduction at home than did respondents with medium incomes, and respondents with medium incomes indicated younger ages to teach about human reproduction at home than did lower income respondents. Two-parent families chose to teach their children about human reproduction at younger ages at school than did single-parent families. Single-parent families chose to teach about birth control methods at home at younger ages than did respondents from two-parent families. Limitations of the study and recommendations for future research were discussed.
53

Microhabitat Selection by Greater Sage-Grouse Hens in Southern Wyoming

Mabray, Scott T. 01 May 2015 (has links)
Greater sage-grouse (Centrocercus urophasianus) populations have declined throughout the western United States over the past 3 decades. Habitat loss within the sagebrush steppe ecosystem is a major factor leading to sage-grouse population decline. Hen sage-grouse were captured, marked, and tracked during the summer of 2012 in southwestern and south-central Wyoming. I performed vegetation surveys, and avian point counts were performed at 1 early-season brood location, 1 late-season brood location, and an accompanying random location for each marked hen regardless of reproductive status. Multinomial models were run to determine what habitat variables were most informative in predicting site selection by hen sage-grouse. During early-brood season, hen sage-grouse with chicks selected sites that had high total shrub cover density; these areas also exhibited high densities of American kestrels (Falco sparverius). They did not avoid areas with common ravens (Corvus corax). Hen sage-grouse not accompanied by a brood selected sites with high total shrub cover and low densities of common ravens and American kestrels. During late-brood season, hen sage-grouse that were accompanied by a brood selected sites with high shrub cover and low densities of small avian predators, such as black-billed magpies (Pica hudsonia) and American kestrels as well as medium-sized predators, such as common ravens, buteo hawks (Buteo spp.), and northern harriers (Circus cyaneus). Hens that were not accompanied by broods were more often found in sites with high total shrub cover and low densities of small avian predators, but selected sites with higher densities of medium-sized predators. Hen sage-grouse select areas with high total shrub cover during early and late-brood season regardless of their reproductive status. By avoiding predators and selecting areas with cover, hens with broods can reduce the risk of their chicks being depredated.
54

Stratigraphy and Paleoecology of the Morrison Formation, Como Bluff, Wyoming

Connely, Melissa V. 01 May 2002 (has links)
The Morrison Formation at Como Bluff, Wyoming, has been historically known for containing a rich source of Late Jurassic vertebrate fossils. However, when collected, most of these fossils were not positioned into a stratigraphic or sedimentologic framework. Research shows that the Morrison Formation at Como Bluff can be divided into three members. These members can be identified by lithologic and paleontological characteristics. The lower Morrison members include the Windy Hill Member and the recently described Lake Como Member. The Windy Hill Member primarily contains near-shore marine sandstone. Megavertebrate fauna is lacking. The Lake Como Member contains illitic clay in red and green mottled paleosols with caliche and thin sandstone beds. The fauna typically consists oflarge saurian and ornithischian dinosaurs. The upper Morrison Formation includes the Talking Rocks Member. This member contains gray-green smectite-rich mudstones. The Talking Rocks Member is generally calcareous and appears to have a megavertebrate fauna similar to the Lower Morrison. The upper part of this member is typically non calcareous and the fauna is more aquatic with turtles, crocodiles, fish and smaller ornithischian dinosaurs, including some species thought to be restricted to the Cretaceous Period. The contact between the Morrison Formation and the overlying Cloverly Formation is placed at the base of the Cloverly conglomerates, which are present throughout the region. In some areas, this boundary coincides with the Jurassic/Cretaceous boundary. However, in sections of the study area, a zone of kaolinitic carbonaceous shale with Cretaceous-like plant material can be found just below the Morrison/Cl overly contact. If this bed is Cretaceous in age, then the Morrison Formation at Como Bluff is in part Early Cretaceous and not restricted to the Late Jurassic.
55

A History of the Latter-Day Settlement of Star Valley, Wyoming

Hall, Ray McCord 01 January 1962 (has links) (PDF)
The Latter-day Saints were good colonizers, possibly because they were repeatedly forced by persecution to seek new homes in the wilderness. Having established themselves in Salt Lake Valley (1847), they began almost immediately to expand their domain. Their Prophet, Brigham Young, sent groups of Mormons to colonize the surrounding valleys, and within a few years there were many Mormon settlements beyond the bounds of Salt Lake Valley. Bear Lake Valley in southeastern Idaho and northern Utah was one of these early settlements.Star Valley--thus named by Moses Thatcher, an Apostle in the Church who thought it was a "star among valleys"--lay in the territory of Wyoming some sixty miles beyond the Bear Lake Valley. Because of its extreme isolation it was slow to attract permanent settlers, although it was used for sumner pasture by the Bear Lake people and it was traversed by many Oregon immigrants who followed the Lander Cut-off.
56

History of Latter-Day Saints in Bridger Valley, Wyoming

Twitchell, Jerry F. 01 January 1959 (has links) (PDF)
The LDS history of Bridger Valley, Wyoming is the name chosen for this project of research into the history of Bridger Valley, Uinta County, Wyoming. This history is intended to cover the settlements in the area.
57

Bridger Formation Sandstones used as an Indication of Tectonics in the Green River Basin and Western Wyoming

Novins, Lisa S. January 1999 (has links)
No description available.
58

A Chronometric Study of the Relation Between Subsistence Intensification and Persistent Land Use during the Middle Holocene in the Wyoming Basin, USA

Reale, Dayna M. 11 October 2016 (has links)
No description available.
59

Succession of ectomycorrhizal fungi associated with Engelmann spruce and subalpine fir in Wyoming

Miller, Steven L. January 1982 (has links)
Fungi associated with Engelmann spruce and subalpine fir were studied in a high altitude area of western Wyoming. Thirty permanent plots were established and their mean stand age determined. Three age classes were delineated: young (78 years), mature (127 years), and old-age (216 years). Stand and soil parameters including density, basal area, and soil pH, P, K, Ca, organic matter, and Mg concentrations were used to define similarities in stand characteristics. Sporocarps of higher basidiomycetes and ascomycetes were collected and identified, and ectomycorrhizal root tips sampled from each plot. Pure cultures of the basidiomycetes were routinely attempted. Mycorrhizal syntheses were subsequently attempted with both tree species using successful pure cultures. Thirty-nine species of higher fungi were collected during the study. Distribution of sporocarps throughout the age classes revealed a distinct fungal flora in each age class. Greatest density of species appeared in the mature stands. Non-mycorrhizal fungi were more abundant in the mature stand while mycorrhizal species were more abundant in the old-age stand. Mycorrhizal root counts increased from young to old-age stands. Low numbers of sporocarps and mycorrhizal rootlets were collected from the young stand. It seems evident from this study that a more diverse assemblage of higher fungi is present in mature and old-age forests and a progressive increase of fungal species from young to old-age stands supports the hypothesis that fungal succession is occurring in the study area. / Master of Science
60

The Greater Sage-grouse in Wyoming: A Technonatural Study

Stubberfield, Alexander Thomas 15 January 2020 (has links)
This dissertation examines the operation of neoliberal environmentality through the instrumentalization of the Greater Sage-grouse (Centrocercus urophasianus) in Wyoming. It treats technological interventions within environmental construction as generating biotic-machinic entanglements termed technonature. I present the formation and operation of the Wyoming Conservation Exchange as a case study of technonatural territorialization connected to global trona and hydrocarbon commodity flows. The theoretical framework elaborates how "the environment" is constructed and governed through tactical instrumental deployments connected to technocratic management allowing economically powerful actors to inscribe their desires within Wyoming's landscape, politics and biota as a function of environmental security related to commodity development. The question motivating this work is "Whose environment is the Environmental Defense Fund defending?" The Greater Sage-grouse has become an object of U.S. Federal environmental governance since the late 1990's. It has experienced significant population declines due to anthropogenic disturbance and habitat loss through industrial action across its range. Wyoming's Sagebrush Steppe contains 37.5% of the remaining range wide population. The grouse was listed as a candidate species under the 1973 U.S. Endangered Species Act triggering responses from Federal, State, and international wildlife management agencies, as well as environmental non-governmental organizations. Wyoming could lose nearly a quarter of its surface should Federal regulations require the designation of critical sage-grouse habitat. Governor Dave Freudenthal signed Executive Order 2008-2 into law in response to the regulatory threat to Wyoming's hydrocarbon and mineral based economy. The grouse, in response was de-listed as a candidate species in 2015 by the U.S. Fish and Wildlife Service. EO 2008-2 established the Wyoming Core Area Strategy as a statewide conservation umbrella and laid the framework for a habitat mitigation economy allowing industrial activity to continue within sage-grouse habitat. This incentivized the Environmental Defense Fund (EDF) to test a market-based instrument – a habitat exchange – within Wyoming. The Greater Sage-grouse is a test species as it is highly sensitive to changes in its environment and this dissertation examines how the habitat mitigation economy advanced by EDF is drawing the grouse into global commodity networks as a territorialization process for global flows of hydrocarbons and minerals. At stake is the ability to write the history of the species, land, and the global environment as EDF develops conservation technologies prioritizing flows critical to the hydrocarbon environment through the technology of the Wyoming Conservation Exchange. / Doctor of Philosophy / The Greater Sage-grouse (Centrocercus urophasianus) entered Euro-American scientific study as early as the Lewis and Clark expedition as they explored the Intermountain region of Western North America. The first thorough scientific study of the sage-grouse in the 20th Century, The Sage Grouse in Wyoming, by Dr. Robert Lansing Patterson included the effects of anthropogenic disturbance on grouse populations. Since the 1952 publication of Patterson's study, Greater Sage-grouse numbers have been declining as the bird loses its home to encroachments such as urbanization, agriculture, grazing, mining, and fossil fuel extraction. The last stronghold of the grouse is the Sagebrush Steppe within Wyoming containing nearly 40% of the remaining population. Known for its flamboyant mating displays, the ground-dwelling avian species has become a political flashpoint in conservation, land management, and environmental circles as its numbers declined steadily since the 1990's due to an accelerating energy boom threatening its habitat. The bird became a threat to extractive industry in Wyoming at the turn of the Millennium as environmentally concerned groups petitioned the U.S. Fish and Wildlife Service (UFWS) to evaluate its populations under the Endangered Species Act (ESA). Nearly a quarter of Wyoming's surface would be strictly policed as critical habitat were the grouse listed as endangered or threatened under the ESA. Wyoming and its partners created the Wyoming Core Area Protection Strategy (CAP) as a wildlife management framework through Executive Order 2008-2. The Wyoming CAP includes the foundation of a habitat mitigation economy allowing industry to trade surface disturbances within critical sage-grouse habitat for modified land purportedly to the benefit of the species. The Nature Conservancy invited the Environmental Defense Fund to form the Wyoming Conservation Exchange – a market-based conservation instrument tailored to trading in habitat mitigation credits. This dissertation studies the Wyoming Conservation Exchange as an instrument connected to larger networks of wildlife management agencies, non-governmental organizations, and mining and fossil fuel interests. It evaluates the effects of the Wyoming Conservation Exchange and the economy it seeks to establish as changing how the environment is managed across the Sagebrush Steppe. Environmental Defense Fund's conservation instrument is reviewed through the economy created for and through the Greater Sage-grouse as an object of environmental governance. Habitat offsetting can, has and will change the physical, and political environment of Wyoming allowing powerful actors to write the rules of how the environment should be managed. As such, this dissertation questions whose environment the Environmental Defense Fund is defending as it explores sage-grouse management within the state.

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