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Articles 1291 - 1320 of 3798

Full-Text Articles in Physical Sciences and Mathematics

Trade-Offs: The Production Of Sustainability In Households, Kirstin Marie Elizabeth Munro Aug 2017

Trade-Offs: The Production Of Sustainability In Households, Kirstin Marie Elizabeth Munro

Dissertations and Theses

Over the past half-century, environmental problems have become increasingly serious and seemingly intractable, and a careless, clueless, or contemptuous consumer is often portrayed as the root cause of this environmental decline. This study takes a different approach to evaluating the demand for resources by households, assessing possible pro-environmental paths forward through a study of highly ecologically-conscious households. By modeling "green" households as producers of sustainability rather than consumers of environmental products, the sustainability work that takes place in households is brought into focus. An investigation of household sustainability production makes possible the evaluation of the trade-offs inherent in these pro-environmental …


A Finite Difference Method For Off-Fault Plasticity Throughout The Earthquake Cycle, Brittany A. Erickson, Eric M. Dunham, Arash Khosravifar Aug 2017

A Finite Difference Method For Off-Fault Plasticity Throughout The Earthquake Cycle, Brittany A. Erickson, Eric M. Dunham, Arash Khosravifar

Mathematics and Statistics Faculty Publications and Presentations

We have developed an efficient computational framework for simulating multiple earthquake cycles with off-fault plasticity. The method is developed for the classical antiplane problem of a vertical strike-slip fault governed by rate-and-state friction, with inertial effects captured through the radiationdamping approximation. Both rate-independent plasticity and viscoplasticity are considered, where stresses are constrained by a Drucker-Prager yield condition. The off-fault volume is discretized using finite differences and tectonic loading is imposed by displacing the remote side boundaries at a constant rate. Time-stepping combines an adaptive Runge-Kutta method with an incremental solution process which makes use of an elastoplastic tangent stiffness tensor …


Low-Dose And In-Painting Methods For (Near) Atomic Resolution Stem Imaging Of Metal Organic Frameworks (Mofs), B. Layla Mehdi, A. J. Stevens, Peter Moeck, Alice Dohnalkova, A. Vjunov, John L. Fulton, Donald M. Camaioni, Omar K. Farha, Joseph T. Hupp, Bruce C. Gates, Johannes A. Lercher, Nigel D. Browning Aug 2017

Low-Dose And In-Painting Methods For (Near) Atomic Resolution Stem Imaging Of Metal Organic Frameworks (Mofs), B. Layla Mehdi, A. J. Stevens, Peter Moeck, Alice Dohnalkova, A. Vjunov, John L. Fulton, Donald M. Camaioni, Omar K. Farha, Joseph T. Hupp, Bruce C. Gates, Johannes A. Lercher, Nigel D. Browning

Physics Faculty Publications and Presentations

Metal-organic Frameworks (MOFs) are a group of crystalline and highly porous materials consisting of inorganic metal ions/clusters (nodes) that are coordinated by organic linkers. The ability to create a wide range of porous structures, where the pore size can be easily changed in size and shape offers the potential for many applications in gas storage/separation and catalysis. The presence of the organic linkers or “struts” in the sample creates challenges for high resolution microscopy as the sample itself is very sensitive to beam damage. A key challenge for understanding the structures of MOFs and how the applications can be modified …


Aryl Transfer Selectivity In Metal-Free Reactions Of Unsymmetrical Diaryliodonium Salts, David Stuart Aug 2017

Aryl Transfer Selectivity In Metal-Free Reactions Of Unsymmetrical Diaryliodonium Salts, David Stuart

Chemistry Faculty Publications and Presentations

Aromatic rings are found in a wide variety of products, including pharmaceuticals, agrochemicals, and functional materials. Diaryliodonium salts are novel reagents used to transfer aryl groups under both metal-free and metal-catalyzed reactions and thereby synthesize arene-containing compounds. This review focuses on recent studies in selective aryl transfer reactions from unsymmetrical diaryliodonium salts under metal-free conditions. Reactions reported from 2008 to 2017, which represents a period of significant growth in diaryliodonium salt chemistry, are presented and organized by the type of reactive intermediate formed in the reaction. Specifically, reactions involving λ3-iodane, λ3-iodane radical anions, aryl radicals, and …


Interactions Among Fuel Management, Species Composition, Bark Beetles, And Climate Change And The Potential Effects On Forests Of The Lake Tahoe Basin, Robert M. Scheller, Alec M. Kretchun, E. Louise Loudermilk, Matthew D. Hurteau, Peter J. Weisberg, Carl Skinner Aug 2017

Interactions Among Fuel Management, Species Composition, Bark Beetles, And Climate Change And The Potential Effects On Forests Of The Lake Tahoe Basin, Robert M. Scheller, Alec M. Kretchun, E. Louise Loudermilk, Matthew D. Hurteau, Peter J. Weisberg, Carl Skinner

Environmental Science and Management Faculty Publications and Presentations

Climate-driven increases in wildfires, drought conditions, and insect outbreaks are critical threats to forest carbon stores. In particular, bark beetles are important disturbance agents although their long-term interactions with future climate change are poorly understood. Droughts and the associated moisture deficit contribute to the onset of bark beetle outbreaks although outbreak extent and severity is dependent upon the density of host trees, wildfire, and forest management. Our objective was to estimate the effects of climate change and bark beetle outbreaks on ecosystem carbon dynamics over the next century in a western US forest. Specifically, we hypothesized that (a) bark beetle …


Knowing Nature In The City: Comparative Analysis Of Knowledge Systems Challenges Along The 'Eco-Techno' Spectrum Of Green Infrastructure In Portland & Baltimore, Annie Marissa Matsler Aug 2017

Knowing Nature In The City: Comparative Analysis Of Knowledge Systems Challenges Along The 'Eco-Techno' Spectrum Of Green Infrastructure In Portland & Baltimore, Annie Marissa Matsler

Dissertations and Theses

Green infrastructure development is desired in many municipalities because of its potential to address pressing environmental and social issues. However, despite technical optimism, institutional challenges create significant barriers to effective green infrastructure design, implementation, and maintenance. Institutional challenges stem from the disparate scales and facility types that make up the concept of green infrastructure, which span from large-scale natural areas to small engineered bioswales. Across these disparate facilities 1) different performance metrics are used, 2) different institutions have jurisdiction, and, 3) facility types are differentially classified as assets, producing epistemological and ontological variegation across the spectrum of green infrastructure that …


The Geography Of Glaciers And Perennial Snowfields In The American West, Andrew G. Fountain, Bryce Glenn, Hassan J. Basagic Aug 2017

The Geography Of Glaciers And Perennial Snowfields In The American West, Andrew G. Fountain, Bryce Glenn, Hassan J. Basagic

Geology Faculty Publications and Presentations

A comprehensive mid-20th century inventory of glaciers and perennial snowfields (G&PS) was compiled for the American West, west of the 100° meridian. The inventory was derived from U.S. Geological Survey 1:24,000 topographic maps based on aerial photographs acquired during 35 years, 1955–1990, of which the first 20 years or more was a cool period with little glacier change. The mapped features were filtered for those greater than 0.01 km2. Results show that 5036 G&PS (672 km2, 14 km3) populate eight states, of which about 1276 (554 km2, 12 km3) are glaciers. …


Properties Of Carbon Nanotubes: Defects, Adsorbates, And Gas Sensing, Micah C. Eastman Jul 2017

Properties Of Carbon Nanotubes: Defects, Adsorbates, And Gas Sensing, Micah C. Eastman

Dissertations and Theses

Carbon nanotubes and graphene have been a trending research topic in the past decade. These graphitic compounds exhibit numerous advantageous properties (electronic, mechanical, thermal, optical, etc) which industry and researchers alike are excited to take advantage of. Beyond the challenges of yield and controlled growth, there are a number of standing questions which govern some of the more fundamental characteristics of these materials: What role do lattice defects play in the adsorption of gas molecules on the surface of carbon nanotubes? How are the electronic states of the carbon nanotubes influenced by these adsorbed molecules? And how can we develop …


The Littlefield Rhyolite, Eastern Oregon: Distinct Flow Units And Their Constraints On Age And Storage Sites Of Grande Ronde Basalt Magmas, Brian Mcculloch Webb Jul 2017

The Littlefield Rhyolite, Eastern Oregon: Distinct Flow Units And Their Constraints On Age And Storage Sites Of Grande Ronde Basalt Magmas, Brian Mcculloch Webb

Dissertations and Theses

The Littlefield Rhyolite consists of widespread, high-temperature, hotspot-related rhyolitic lavas that erupted in eastern Oregon contemporaneous to late-stage Grande Ronde Basalt lavas. The estimated total volume of erupted rhyolites is ~100 km3 covering ~850 km2.

The focus of this study has been to investigate the stratigraphy and petrology of the Littlefield Rhyolite and whether field and geochemical relationships exist to help constrain the timing and storage sites of Grande Ronde Basalt magmas. Although often indistinguishable in the field, our data reveal that the Littlefield Rhyolite consists of two geochemically distinct rhyolite flow packages that are designated here …


High-Resolution Elevation Mapping Of The Mcmurdo Dry Valleys, Antarctica, And Surrounding Regions, Andrew G. Fountain, Juan C. Fernandez-Diaz, Maciej K. Obryk, Joseph Levy, Michael N. Gooseff, David J. Van Horn, Paul Morin, Ramesh Shrestha Jul 2017

High-Resolution Elevation Mapping Of The Mcmurdo Dry Valleys, Antarctica, And Surrounding Regions, Andrew G. Fountain, Juan C. Fernandez-Diaz, Maciej K. Obryk, Joseph Levy, Michael N. Gooseff, David J. Van Horn, Paul Morin, Ramesh Shrestha

Geology Faculty Publications and Presentations

We present detailed surface elevation measurements for the McMurdo Dry Valleys, Antarctica derived from aerial lidar surveys flown in the austral summer of 2014–2015 as part of an effort to understand geomorphic changes over the past decade. Lidar return density varied from 2 to > 10 returns m−2with an average of about 5 returns m−2. Vertical and horizontal accuracies are estimated to be 7 and 3 cm, respectively. In addition to our intended targets, other ad hoc regions were also surveyed including the Pegasus flight facility and two regions on Ross Island, McMurdo Station, Scott Base (and surroundings), and the coastal …


Dynamically Distinguishing Polynomials, Andrew Bridy, Derek Garton Jul 2017

Dynamically Distinguishing Polynomials, Andrew Bridy, Derek Garton

Mathematics and Statistics Faculty Publications and Presentations

A polynomial with integer coefficients yields a family of dynamical systems indexed by primes as follows: For any prime p, reduce its coefficients mod p and consider its action on the field FpFp. We say a subset of Z[x]Z[x] is dynamically distinguishable mod p if the associated mod pdynamical systems are pairwise non-isomorphic. For any k,M∈Z>1k,M∈Z>1, we prove that there are infinitely many sets of integers MM of size M such that {xk+m∣m∈M}{xk+m∣m∈M} is dynamically distinguishable mod p for most p (in the sense of natural density). Our proof uses the Galois theory of dynatomic polynomials largely developed …


Assessing The Potential Of Land Use Modification To Mitigate Ambient No2 And Its Consequences For Respiratory Health, Meenakshi Rao, Linda A. George, Vivek Shandas, Todd N. Rosenstiel Jul 2017

Assessing The Potential Of Land Use Modification To Mitigate Ambient No2 And Its Consequences For Respiratory Health, Meenakshi Rao, Linda A. George, Vivek Shandas, Todd N. Rosenstiel

Urban Studies and Planning Faculty Publications and Presentations

Understanding how local land use and land cover (LULC) shapes intra-urban concentrations of atmospheric pollutants—and thus human health—is a key component in designing healthier cities. Here, NO2 is modeled based on spatially dense summer and winter NO2 observations in Portland-Hillsboro-Vancouver (USA), and the spatial variation of NO2 with LULC investigated using random forest, an ensemble data learning technique. The NO2 random forest model, together with BenMAP, is further used to develop a better understanding of the relationship among LULC, ambient NO2 and respiratory health. The impact of land use modifications on ambient NO2, …


Psu Green Building Summer Internship Final Report, 2017: Interior Environmental And Indoor Air Quality Assessments Of Workspaces For Future Maintenance Of Parkmill’S Constant Air Volume (Cav) Hvac System, Bassam Alduhaim, Sofia Chavez Cruz Jul 2017

Psu Green Building Summer Internship Final Report, 2017: Interior Environmental And Indoor Air Quality Assessments Of Workspaces For Future Maintenance Of Parkmill’S Constant Air Volume (Cav) Hvac System, Bassam Alduhaim, Sofia Chavez Cruz

Campus Sustainability Office Publications, Reports and Presentations

Parkmill’s Design, Construction, and Mechanical Systems

The Parkmill building is located on the lower south section of Portland State University’s (PSU) urban campus between SW Park Avenue and SW Mill Street.The lot space, originally selected for the design proposal in 1956, was located between two buildings including the acquired Parkway Manor (currently designated as PSU housing) and former frame house-type buildings. The proposed building would supplement the evening and summer curriculum courses offered by the General Education Division (GED) in partnership with Portland State College and would become a vital resource for students in the Portland metropolitan area.


Green Leasing Program Design For Psu, Emily Quinton Jul 2017

Green Leasing Program Design For Psu, Emily Quinton

Campus Sustainability Office Publications, Reports and Presentations

Portland State University (PSU) serves as a Landlord to over 60 third-party tenants, including retail, food service, office, food cart, and other tenant types. To encourage and standardize the adoption and practice of sustainability behaviors among these tenants, PSU hired a Green Leasing Intern during the summer of 2017. The intern, graduate student Emily Quinton, managed by members of the PSU Planning, Construction & Real Estate (PCRE) team, was tasked with researching best practices, drafting green leasing language, and developing tenant engagement and incentive-based approaches to implementation. This report serves as the culminating deliverable for that internship. Additional internship documentation …


A Statistical Investigation Of Lower Columbia River Water Temperature, 1915-2003, Corina Christina Mae Overman Jul 2017

A Statistical Investigation Of Lower Columbia River Water Temperature, 1915-2003, Corina Christina Mae Overman

Civil and Environmental Engineering Undergraduate Honors Theses

The Columbia River is home to anadromous salmon populations that migrate upriver every year to spawn. These fish require cool water temperatures (Tw) to survive. In recent years, high summer Tw in the Columbia River has caused increased mortality of salmon. Different possible explanations for increased Tw include climate change, deforestation, and decreased summertime streamflow (Q) due to dams. In this study, robust linear regression models of Tw based on air temperature (Ta) and Q were developed to examine the change in Tw over time. The data was …


Spatial-Semantic Image Search By Visual Feature Synthesis, Mai Long, Hailin Jin, Chen Fang, Feng Liu Jul 2017

Spatial-Semantic Image Search By Visual Feature Synthesis, Mai Long, Hailin Jin, Chen Fang, Feng Liu

Computer Science Faculty Publications and Presentations

The performance of image retrieval has been improved tremendously in recent years through the use of deep feature representations. Most existing methods, however, aim to retrieve images that are visually similar or semantically relevant to the query, irrespective of spatial configuration. In this paper, we develop a spatial-semantic image search technology that enables users to search for images with both semantic and spatial constraints by manipulating concept text-boxes on a 2D query canvas. We train a convolutional neural network to synthesize appropriate visual features that captures the spatial-semantic constraints from the user canvas query. We directly optimize the retrieval performance …


Time Varying Parameter Models For Catchments With Land Use Change: The Importance Of Model Structure, Sahani Pathiraja, Daniela Anghileri, Paolo Burlando, Ashish Sharma, Lucy Marshall, Hamid Moradkhani Jul 2017

Time Varying Parameter Models For Catchments With Land Use Change: The Importance Of Model Structure, Sahani Pathiraja, Daniela Anghileri, Paolo Burlando, Ashish Sharma, Lucy Marshall, Hamid Moradkhani

Civil and Environmental Engineering Faculty Publications and Presentations

Rapid population and economic growth in South-East-Asia has been accompanied by extensive land use change with consequent impacts on catchment hydrology. Modelling methodologies capable of handling changing land use conditions are therefore becoming ever more important, and are receiving increasing attention from hydrologists. A recently developed Data Assimilation based framework that allows model parameters to vary through time in response to signals of change in observations is considered for a medium sized catchment (2880 km²) in Northern Vietnam experiencing substantial but gradual land cover change. We investigate the efficacy of the method as well as the importance of the chosen …


Urban Connections: A Comparison Of Connectivity Assessment Methods, Natalie M. Rogers Jul 2017

Urban Connections: A Comparison Of Connectivity Assessment Methods, Natalie M. Rogers

Environmental Science and Management Professional Master's Project Reports

Habitat connectivity in urban settings is critical for facilitation of safe species movement, species health, and biodiversity. Predicting the movement of wildlife through the urban environment is difficult due to the presence of barriers - natural or built features in the landscape that restrict or prohibit movement of species. Urban properties and greenspaces can serve as pathways of connectivity for wildlife movement across the complex developed matrix. Thus, land managers should assess their properties for possible connectivity functionality to promote safe wildlife movement. Land managers may not be aware of current connectivity assessment methods, therefore this project provides introductory information …


Bending The Carbon Curve: Fire Management For Carbon Resilience Under Climate Change, E. Louise Loudermilk, Robert M. Scheller, Peter J. Weisberg, Alec M. Kretchun Jul 2017

Bending The Carbon Curve: Fire Management For Carbon Resilience Under Climate Change, E. Louise Loudermilk, Robert M. Scheller, Peter J. Weisberg, Alec M. Kretchun

Environmental Science and Management Faculty Publications and Presentations

Context: Forest landscapes are increasingly managed for fire resilience, particularly in the western US which has recently experienced drought and widespread, high-severity wildfires. Fuel reduction treatments have been effective where fires coincide with treated areas. Fuel treatments also have the potential to reduce drought-mortality if tree density is uncharacteristically high, and to increase long-term carbon storage by reducing high-severity fire probability.

Objective: Assess whether fuel treatments reduce fire intensity and spread and increase carbon storage under climate change.

Methods: We used a simulation modeling approach that couples a landscape model of forest disturbance and succession with an ecosystem model of …


Effectiveness Of Indoor Plants For Passive Removal Of Indoor Ozone, Omed A. Abbass, David J. Sailor, Elliott T. Gall Jul 2017

Effectiveness Of Indoor Plants For Passive Removal Of Indoor Ozone, Omed A. Abbass, David J. Sailor, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Indoor vegetation is often proposed as a passive approach for improving indoor air quality. While studies of outdoor environments indicate that vegetation can be an important sink of outdoor ozone, there is scant data in the literature concerning the dynamics of ozone uptake by indoor plants. This study determined ozone deposition velocities (vd) for five common indoor plants (Peace Lily, Ficus, Calathia, Dieffenbachia, Golden Pothos). The transient vd was calculated, using measured leaf areas for each plant, for exposures mimicking three diurnal cycles where ozone concentrations in chamber tests were elevated for 8 h followed by …


Ecological Homogenization Of Residential Macrosystems, Peter M. Groffman, Meghan Avolio, Jeannine Cavender-Bares, Neil D. Bettez, J. Morgan Grove, Sharon J. Hall, Sarah E. Hobbie, Kelli L. Larson, Susannah B. Lerman, Dexter H. Locke, James B. Heffernan, Jennifer L. Morse, Christopher Neill, Kristen C. Nelson, Jarlath O'Neil-Dunne, Diane E. Pataki, Colin Polsky, Rinku Roy Chowdhury, Tara Trammell Jul 2017

Ecological Homogenization Of Residential Macrosystems, Peter M. Groffman, Meghan Avolio, Jeannine Cavender-Bares, Neil D. Bettez, J. Morgan Grove, Sharon J. Hall, Sarah E. Hobbie, Kelli L. Larson, Susannah B. Lerman, Dexter H. Locke, James B. Heffernan, Jennifer L. Morse, Christopher Neill, Kristen C. Nelson, Jarlath O'Neil-Dunne, Diane E. Pataki, Colin Polsky, Rinku Roy Chowdhury, Tara Trammell

Environmental Science and Management Faculty Publications and Presentations

Similarities in planning, development and culture within urban areas may lead to the convergence of ecological processes on continental scales. Transdisciplinary, multi-scale research is now needed to understand and predict the impact of human-dominated landscapes on ecosystem structure and function


Origins Of Late- Pleistocene Coastal Dune Sheets, Magdalena And Guerrero Negro, From Continental Shelf Low-Stand Supply (70-20 Ka), Under Conditions Of Southeast Littoral- And Eolian-Sand Transport, In Baja California Sur, Mexico, Curt D. Peterson, Janette Murillo-Jiminez, Errol Stock, David M. Price, Steve W. Hostetler, David Percy Jul 2017

Origins Of Late- Pleistocene Coastal Dune Sheets, Magdalena And Guerrero Negro, From Continental Shelf Low-Stand Supply (70-20 Ka), Under Conditions Of Southeast Littoral- And Eolian-Sand Transport, In Baja California Sur, Mexico, Curt D. Peterson, Janette Murillo-Jiminez, Errol Stock, David M. Price, Steve W. Hostetler, David Percy

Geology Faculty Publications and Presentations

Shallow morpho-stratigraphic sections (n = 11) in each of two large coastal dune sheets including the Magdalena (7000 km2) and Guerrero Negro (8000 km2) dune sheets, from the Pacific Ocean side of Baja California Sur, Mexico, have been analyzed for dune deposit age. The shallow morpho-stratigraphic sections (∼2-10 m depth) include 11 new TL and 14C ages, and paleosol chronosequences, that differentiate cemented late Pleistocene dune deposits (20.7 ± 2.1 to 99.8 ± 9.4 ka) from uncemented Holocene dune deposits (0.7 ± 0.05 to at least 3.2 ± 0.3 ka). Large linear dune ridges (5-10 m …


The Effect Of Salinity Acclimation On The Upper Thermal Tolerance Threshold Of The European Green Crab, Lauren S. Muñoz-Tremblay, A. L. Kelley, Catherine De Rivera Jun 2017

The Effect Of Salinity Acclimation On The Upper Thermal Tolerance Threshold Of The European Green Crab, Lauren S. Muñoz-Tremblay, A. L. Kelley, Catherine De Rivera

Environmental Science and Management Faculty Publications and Presentations

Fluctuations in salinity and temperature, among other varying environmental conditions, are stressors in estuaries and may work together to alter the physiological response of organisms that inhabit such environments. Laboratory assessments that investigate how animals respond to multiple environmental stressors can provide an ecological framework for understanding physiological performance across varying conditions. In this study, European green crabs, Carcinus maenas, were collected from Seadrift Lagoon, California, USA (37°54′27.82″N, 122°40′19.56″W) and were lab-acclimated at three different salinity concentrations typical of many estuaries: 15, 25, and 35 PSU at 12 °C (± 1 °C). After acclimation, crabs from each salinity treatment experienced …


Rhyolite Petrogenesis At Tower Mountain Caldera, Or, Elizabeth Ann Brown Jun 2017

Rhyolite Petrogenesis At Tower Mountain Caldera, Or, Elizabeth Ann Brown

Dissertations and Theses

Tower Mountain Caldera is the main feature of an Oligocene volcanic field located in the Umatilla National Forest, eastern Oregon. It is perfectly suited to investigate models of rhyolite petrogenesis as all of the important rock components for evaluating generation models are present in a single location and thus are presumably related; basalts, intermediate igneous rocks (which consist of older plutons and younger volcanic rocks, which are ~coeval with rhyolites), metamorphic basement rocks of significant grade, and rhyolites of varying composition. The formation of the caldera produced the Dale Tuff, which comprises the intra-caldera and outflow facies. 40Ar/39 …


Mineral Evidence For Generating Compositionally Zoned Rhyolites Of The Devine Canyon Tuff, High Lava Plains, Oregon, Erik Paul Shafer Jun 2017

Mineral Evidence For Generating Compositionally Zoned Rhyolites Of The Devine Canyon Tuff, High Lava Plains, Oregon, Erik Paul Shafer

Dissertations and Theses

Large-volume silicic eruptions are often evacuated from magma reservoirs which display gradients in composition, temperature, crystallinity, and volatile content. The 9.7 Ma Devine Canyon Tuff (DCT) of eastern Oregon represents such an eruption, with >300 km³ of compositionally zoned pyroclastic material deposited as a variably-welded ignimbrite. The ignimbrite displays homogenous bulk tuff major element compositions with a wide range of trace element compositions, allowing for the investigation of how these magmas were generated, stored, and modified in the magma reservoir by studying pumices which represent the primary magmas composing the DCT. Five pumices ranging from dacite to rhyolite bulk compositions …


Investigation In To The Stabilizing Effects Of The Modified Base Archaeosine In Trna And The Identification Of The Fluorescent Product Of Base Treatment Of Nad(P)+ Cofactors, Ben Turner Jun 2017

Investigation In To The Stabilizing Effects Of The Modified Base Archaeosine In Trna And The Identification Of The Fluorescent Product Of Base Treatment Of Nad(P)+ Cofactors, Ben Turner

Dissertations and Theses

This dissertation covers two projects linked by their involvement in the modification of tRNA bases.

The first project focused on an investigation of a role for the modified base Archaeosine, the ubiquitous modification in tRNA in the archaeal domain. Initial work was performed on a set of in vitro prepared tRNA modified to feature either the canonical guanine base at position 15, preQ0 (TGT product) or Archaeosine (ArcS product). There was very little difference in the thermal stability of tRNAs containing these modifications in the halophilic H. volcanii tRNASer or E. coli tRNAGln. In tRNAGln …


Ecosystem Recovery In Estuarine Wetlands Of The Columbia River Estuary, Sarah Ann Kidd Jun 2017

Ecosystem Recovery In Estuarine Wetlands Of The Columbia River Estuary, Sarah Ann Kidd

Dissertations and Theses

In the restoration of tidal wetland ecosystems, potential drivers of plant community development range from biotic controls (e.g. plant competition, seed dispersal) to abiotic controls (e.g. tidal flooding, salinity levels). How these controls influence the success of tidal wetland restoration are only partly understood, but have important implications for wetland habitat recovery. Specifically, the extent to which the existing native and non-native seed banks in tidally reconnected wetlands interact with these controls is not clear, yet the potential success of passive restoration methods depends upon this understanding.

For a 54-year chronosequence of eleven tidal wetland restoration sites in the Lower …


Analyzing Dam Feasibility In The Willamette River Watershed, Alexander Cameron Nagel Jun 2017

Analyzing Dam Feasibility In The Willamette River Watershed, Alexander Cameron Nagel

Dissertations and Theses

This study conducts a dam-scale cost versus benefit analysis in order to explore the feasibility of each the 13 U.S. Army Corps of Engineers (USACE) commissioned dams in Oregon’s Willamette River network. Constructed between 1941 and 1969, these structures function in collaboration to comprise the Willamette River Basin Reservoir System (WRBRS). The motivation for this project derives from a growing awareness of the biophysical impacts that dam structures can have on riparian habitats. This project compares each of the 13 dams being assessed, to prioritize their level of utility within the system. The study takes the metrics from the top …


The Camkii Holoenzyme Structure In Activation Competent Conformations, Janette B. Myers, Vincent Zaegel, Steven J. Coultrap, Adam P. Miller, K. Ulrich Bayer, Steve L. Reichow Jun 2017

The Camkii Holoenzyme Structure In Activation Competent Conformations, Janette B. Myers, Vincent Zaegel, Steven J. Coultrap, Adam P. Miller, K. Ulrich Bayer, Steve L. Reichow

Chemistry Faculty Publications and Presentations

The Ca2+/calmodulin-dependent protein kinase II (CaMKII) assembles into large 12-meric holoenzymes, which is thought to enable regulatory processes required for synaptic plasticity underlying learning, memory and cognition. Here we used single particle electron microscopy (EM) to determine a pseudoatomic model of the CaMKIIα holoenzyme in an extended and activation-competent conformation. The holoenzyme is organized by a rigid central hub complex, while positioning of the kinase domains is highly flexible, revealing dynamic holoenzymes ranging from 15–35 nm in diameter. While most kinase domains are ordered independently, ~20% appear to form dimers and


Columbia River Basin Salmon And Steelhead Long-Term Recovery Situation Assessment, Oregon Solutions, William D. Ruckelshaus Center Jun 2017

Columbia River Basin Salmon And Steelhead Long-Term Recovery Situation Assessment, Oregon Solutions, William D. Ruckelshaus Center

National Policy Consensus Center Publications and Reports

In the fall of 2012, after consulting with a wide range of salmon recovery partners, NOAA Fisheries asked Oregon Consensus and the William D. Ruckelshaus Center (university-based, neutral, third-party institutions devoted to promoting collaborative governance and consensusbased public policy) to conduct an independent, impartial situation assessment to explore regional views about how best to approach comprehensive, long-term salmon and steelhead recovery in the Basin. The centers assembled an Assessment Team comprised of practitioners and academics from Washington, Oregon and Idaho.

The Assessment Team conducted 206 semi-structured interviews with individuals selected for their knowledge of, engagement in, and/or concern for salmon …