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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

Selenium and trace metal accumulation in detrital-benthic food webs of lotic and lentic wetlands, Utah, USA

Hillwalker, Wendy E. 24 May 2004 (has links)
Concentrations of selenium (Se), manganese (Mn), zinc (Zn), cadmium (Cd), lead (Pb) and arsenic (As) were measured in the water column, sediment and biota, in conjunction with selected physicochemical data, from representative wetland types at a mining site within Salt Lake County, Utah, USA. The selected field sites included Oolitic Pond (lentic) and Lee Creek (lotic), which are moderately contaminated brackish, alkaline aquatic wetlands managed by a copper mining industry. These fishless wetlands are located in a geographic region that poses risk to migratory shorebird populations from dietary Se. A spatial sampling study demonstrated the extent of variation in total Se concentration within the wetlands. With the exception of the sediment compartment, Se concentration did not differ significantly along the 2-mile length of Lee Creek or within the Pond. The differences in sediment total Se concentrations between the Creek East and West segments characterize lower Lee Creek as having two segments distinguished by unique processes that influence the sediment Se accumulation profiles. Se accumulation trends were observed temporally over 3-years (2000 to 2002) and over two seasons (spring and autumn). Total Se body burden in benthic invertebrates was more clearly associated with sediment/detritus Se concentrations than with surface water concentrations. Three invertebrate groups dominated the aquatic invertebrates assemblage in the lotic and lentic benthos; primary consumers (Chironomidae, Diptera), generalist feeders (Hemiptera) and predators (Odonata). The chironomid larvae accumulated 1.3 to 39 times the trace metal concentrations of the Hemiptera or odonate taxa, independent of trace metal type (essential or non-essential) or wetland occupation. Organism-specific factors, such as habitat selection and preferential feeding habits, were proposed to influence benthic invertebrate accumulation profiles by modifying trace metal exposure. Mixed diets, trophic omnivory and the complexity of wetland biogeochemistry limit the power of stable nitrogen fractionation signatures to define benthic food web relationships. Wetland site-specific processes impacted Se accumulating efficiency, with trace metal concentrations from 4 to 7 times greater within the lentic benthic system than the lotic. The fractionation of the natural abundant stable carbon isotopes revealed the importance of sedimentary and detrital organic carbon as dietary sources for the benthic food web. Sediment organic content was not significantly associated with sediment, or invertebrate, Se accumulation profiles. Ecological risk assessments based on sound understanding of metal chemistry and the interactions between the sediment matrix and benthic organisms are necessary to provide tools for environmental management. / Graduation date: 2005
2

Precinct Government in Salt Lake County, Utah 1852-1904

Madsen, Steven K. 01 January 1986 (has links) (PDF)
This thesis traces the origin, development, and decline, from 1852 to 1904, of Salt Lake County's judicial precincts. A precinct functioned as the basic subdivision of county government. Its boundaries were generally coterminous with those of local communities. It was established to allow for a degree of local control by the people.Chapter two reveals that precinct justices experienced over time a marked decline in socio-political prominence. This is largely due to legislative statutes that decreased their jurisdictional powers. Chapter three examines the evolution of precinct boundaries. It is demonstrated that geographic distribution of individuals played a major role in the growth and eventual consolidation of community precincts. The relative availability of government services also fostered the development of county districts. Chapter four studies the role of the minor precinct officials in local government--constables, estray poundkeepers, and fenceviewers. The last chapter devotes attention to the factors that influenced the institution. The appendix lists the county's justices of the peace from 1852 to 1904.
3

Need for Post-High School Technical Training in Ornamental Horticulture in Davis, Salt Lake, and Utah Counties

Peterson, Paul 01 May 1969 (has links)
The need for a technician training program in Ornamental Horticulture was studied in Davis, Salt Lake and Utah counties utilizing interviews and mailed survey instruments. The greatest job increase during the next five years is anticipated for nursery workers, landscape helpers and greenhouse workers. The smallest anticipated increase is for florists, floor foreman and nursery technicians. Skills requiring the highest degree of competency for workers in ornamental horticulture, according to employers, are retail salesmanship, plant identification and disease and insect control. Courses receiving the highest rating in an ornamental horticulture technician curriculum, as given by owners and managers and by educators, were botany, ornamental deciduous woody plants, soils and fertilizers, gardening techniques, and plant propagation. Courses receiving the lowest rating were three months or more on-the-job training, professional ethics and law, and economic entomology.
4

The Historical Development of Wasatch Trails in Salt Lake County

Hardy, Clyde Brian 01 January 1975 (has links) (PDF)
In this study investigation was made concerning the etiology of the foot trails that thread their way through Wasatch Forest lands in Salt Lake county. The time delimitation was 1847 to 1975.The origin of the majority of these trails dates back to the nineteenth century and is closely tied to the efforts of pioneers who labored to wrest a living from semi-arid land. Early lumbering, livestock operations, mining activities, water collection systems, and pioneer recreation all provided impetus for trail development. In a sense these trails are a kind of anthology of human endeavor.Passing into the twentieth century it was found that with the exception of emergency relief programs, particularly the Civilian Conservation Corps, very little development has occurred and trail maintenance has been inadequate.Trail prestige increased in the wake of the surge of interest that found legislative expression in the National Trails System Act of 1968. However, in recent years they have been subordinated in the face of what are considered to be matters of great urgency.
5

A study of the plant ecology of Salt Lake and Utah valleys before the Mormon immigration

Wakefield, John Homer 22 May 1933 (has links)
This study is an attempt to bring together such available material , heretofore not collected, into a single compilation pertaining to the plant associations of Utah and Salt Lake Valleys. An endeavor is made to build a picture of the vegetation as it was before the pioneers entered these valleys as compared with what it is today. The material compiled here is the result of searching through all available sources such as government reports of geological explorations, private diaries of explorers and pioneers , contemporary magazines, books and newspapers .

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