Physical Sciences and Mathematics Commons^™

Biological Control Of Purple Loosestrife (Lythrum Salicaria): Factors Affecting Galerucella Pusilla And Galerucella Calmariensis Establishment In Tidal Areas, Lynda Kathryn Moore

Dissertations and Theses

Galerucella pusilla and G. calmariensis have provided successful biological control of purple loosestrife (Lythrum salicaria L.) in non-tidal areas but only marginal control in areas of tidal influence. While a previous study identified mechanical scour by tidal waters as the main cause of establishment failure, purple loosestrife stem density explained more than 80% of the variability in presence and absence of Galerucella at my study sites in the Columbia River Estuary. A logistic regression model using purple loosestrife stem density, elevation, and their interaction as predictors accurately predicted 92.5% of Galerucella presence or absence observations of a test data …

Effects Of Tide Gate Replacement On Water Temperature In A Freshwater Slough In The Columbia River Estuary, Sara Ennis

Environmental Science and Management Professional Master's Project Reports

Dramatic declines in salmon populations in the Pacific Northwest have brought new attention to the importance of estuarine rearing habitats. Levees and tide gates used to convert estuarine wetlands into farmland have reduced available habitat by more than half of historical levels. Recent efforts to restore estuarine habitats include tide gate replacement, though this method has been poorly studied. As a key indicator of salmon habitat suitability, temperature was used to evaluate the effects of tide gate replacement in a tidally influenced freshwater slough in the Lower Columbia River estuary. Three tide gates in the largest slough on Tenasillahe Island …

Invasive Species Management Plan For Oswego Lake, Daniel Warren, Mark Sytsma

Environmental Science and Management Professional Master's Project Reports

This Invasive Species Management Plan defines an overarching strategy for the Lake Oswego Corporation (LOC) to mitigate threats from invasive species to Oswego Lake. Invasive species pose a direct risk to recreational and aesthetic uses of the lake, critical LOC infrastructure, and ecological communities within the lake. The Plan is particularly concerned with two bivalve mollusks in the genus Dreissena: the zebra mussel (Dreissena polymorpha) and the quagga mussel (Dreissena bugensis). These mussels grow in dense colonies that damage watercraft and underwater structures as well as displace native species. A recent scientific report found that …

Comparison Of The Focal Properties Of Selected Magnetic And Electrostatic Lenses And Tests Of Their Theoretical Models, Luis Thomas Almarez

Dissertations and Theses

The main goal of the present research is to determine whether there is a significant difference between the aberrations of magnetic and electrostatic electron lenses when they are used in the same way. Comparison of the lenses was done in an electron-optical bench, set up to resemble a scanning electron microscope (SEM). Five different lenses, two magnetic and three electrostatic, were compared. Each group included two lenses with different lens-field lengths (pole-face spacing in magnetic lenses and interior length in electrostatic lenses). The lenses were used in turn to focus the electron beam into a demagnified image, or probe. The …

Active Site Chemistry Of The Nadph-Dependent:7-Cyano-7-Deazaguanine (Preq0) Nitrile Oxidoreductase, An Enzyme Involved In Queuosine Biosynthesis, Bobby Wai Keung Lee

Dissertations and Theses

Queuosine (Q) is a modified nucleoside found at the wobble position of bacterial and eukaryotic transfer RNAs (tRNAs) that are specific for the amino acids tyrosine, histidine, aspartate and asparagine. A recently discovered enzyme in the biosynthetic pathway of Q, the NADPH-dependent 7-cyano-7-deazaguanine oxidoreductase (QueF), carries out the two-fold, four-electron reduction of Q precursor preQ0 to preQ1 and represents the first example of the enzymatic conversion of the nitrile functional group to an amine. Presented herein are kinetic, spectroscopic, mutational, biophysical, and isotope labeling studies directed at the elucidation of the chemical and kinetic mechanisms of this new class of …

Prediction Of Persistence Of Fertilizer-Derived Cadmium In Oregon Agricultural Soils Using Equilibrium Modeling And Fertilizer Release Kinetics, Fungai Mukome

Dissertations and Theses

Organic farming has become a multimillion dollar industry and while much emphasis is put on subsequent fertilizer inputs onto these fields, very little consideration is given to the prior fertilization activities of these soils. For a farm to be certified organic it means no harmful chemicals have been applied for at least three years.

The overall hypothesis tested by this research was that equilibrium adsorption models can adequately represent the behavior of fertilizer-derived cadmium in Oregon agricultural soils and that such model results can be easily incorporated into risk assessment models, transport study models and persistence studies for organic or …

Vegetation, Environmental Characteristics, And Their Relationships: Variation Within The Annually Flooded Riparian Zones Of The John Day River Basin, Oregon, Samuel J. Hartsfield

Dissertations and Theses

I hypothesized that vegetation and physical environmental characteristics would differ between the upper and lower extents of the annually flooded riparian zone on the John Day River, and that relationships between species and environmental variables would display differences between these two zones. Vegetation, environmental variables, and relationships between them were assessed for the entire annually flooded riparian zone, and for the proposed upper and lower zones. Data were collected from 60 one-square-meter quadrats: 30 in each the upper and lower zones. Sites were randomly selected and located so that flood duration was roughly equal at all sites within each zone. …

The Role Of Water And Other Resources In The Invasion Of Rubus Armeniacus In Pacific Northwest Ecosystems, Joshua Sundance Caplan

Dissertations and Theses

The factors influencing the invasive success of Rubus armeniacus (Himalayan blackberry) in the Pacific Northwest of North America are only partly understood, but have important implications for its management and for our understanding of the processes driving invasive plant proliferation in regions with seasonally fluctuating resources. I identified patterns of R. armeniacus occurrence and growth under widely ranging soil and light conditions in western Oregon. I found that light availability was a primary determinant of R. armeniacus occurrence and growth. I also found that R. armeniacus was tolerant of a wide range of soil conditions, notably coarse texture, and could …

Studies Of Dna Hybridization Reactions And Applications In Genetic Assays, Fidelis Manyanga

Dissertations and Theses

The intent of this study was to investigate two fundamental aspects of short DNA duplex stability and how that stability differs for duplex molecules consisting of either all perfect match Watson/Crick base pairs or a mixture of perfect match Watson/Crick base pairs and mismatch base pairs. Theoretical and experimental investigations of the origins of the nucleation term in the free energy of DNA duplex formation were revisited. Thermodynamic parameters (ΔG, ΔH, Δ S and Tm) of short DNA/DNA duplexes ranging in length from 6 to 35 base pairs were systematically evaluated by Differential Scanning Calorimetry …

Calculating The Volume Of The May 18, 1980 Eruption Of Mount St. Helens, Dâvid Nuñez Wickham

Environmental Science and Management Professional Master's Project Reports

The May 18, 1980 eruption of Mount St. Helens created a massive amount of sediment and debris, thought to be as much as 5.5 billion cubic yards. This sediment causes infill of river stretches and collects along levees protecting southwest Washington State. The sediment must be removed to ensure these areas do not flood. The US Army Corps of Engineers (USACOE) is tasked with flood protection for southwest Washington State and the levees protecting the cities of Castle Rock, Lexington, Kelso, and Longview. The Sediment Retention Dam, opened in 1989 is able to filter out larger particulate but fine grain …

State Of The River Report For Toxics, Bradley Carter

Environmental Science and Management Professional Master's Project Reports

The United States Environmental Protection Agency (EPA) strives to prevent pollution, protect water quality and improve ecosystems in order to reduce risks to human health and the environment. As outlined in the Agency’s Strategic Plan, the Columbia River Basin was identified as a "National Priority" and designated as one of our nation’s seven "Large Aquatic Ecosystems". This designation grants legislative status equal to the Chesapeake Bay, Great Lakes, Gulf of Mexico, South Florida Ecosystem, Long Island Sound and Puget Sound. The Strategic Plan is the Agency’s road map of future work efforts, and targets specific goals that are expected to …

The Mckee Preserve Management Options At Bandon Dunes Golf Resort, Ashley Marie Edwards

Environmental Science and Management Professional Master's Project Reports

The McKee Preserve is a new conservation area at Bandon Dunes Golf Resort, located on the southern Oregon coast. The Preserve is 250 acres in size and is made up of 13 different natural resource communities. One important resource is silvery phacelia (Phacelia argentea), which is a state threatened plant species and is a species of concern federally. The goal of this project was to perform plant inventories for silvery phacelia and kinnikinnick that will be used to establish a functional management plan for the Preserve. Other resources of interest to the Preserve have been included in the …

Downspout Disconnection Suitability And Incentives Analysis For The City Of Gresham, Oregon, Brian C. Fletcher

Environmental Science and Management Professional Master's Project Reports

The City of Gresham is developing a Downspout Disconnection Program, which encourages homeowners to disconnect their roof downspouts from the storm sewer system and divert the stormwater onto their lawn or rain garden. Downspout disconnection is being evaluated for its effectiveness to help the city meet stormwater discharge requirements in their NPDES-MS4 permit from Oregon DEQ. This study reviewed current Natural Resources Conservation Service (NRCS) soil data and developed a suitability map showing High, Medium and Low suitability zones for on-site stormwater management. To validate the map, 55 soil textural classes and 11 infiltration rates were determined at residences throughout …