Digital Commons Network^™

Controlled Fabrication Of High-Yield Cds Nanostructures By Compartment Arrangement, Joshua M. Green, Juno Lawrance, Jun Jiao

Physics Faculty Publications and Presentations

High-yield, high-purity CdS nanostructures were synthesized in a turf-like configuration using an improved vapor-liquid-solid method. To increase the yield, a compartment arrangement was employed. The specific kind of nanostructure fabricated was found to be directly dependent on the temperature in the compartment. Along with the high-yield growth of CdS nanorods, nanowires, and nanobelts, intertwined structures were also observed, and the electron field emission property of the intertwined structures was investigated and compared with that of other type of nanostructures. Photoluminescence measurements at 10 K showed a peak emission from the CdS nanostructures at 485 nm.

Bulletin: General Catalog Issue 2008-2009, Portland State University

Bulletin & Curriculum Change Documents

No abstract provided.

Floodplains: Balancing Nature And Human Needs, Vivek Shandas, Meg Merrick

Institute for Sustainable Solutions Publications and Presentations

For countless years, the interaction between climatic conditions and water flow has forged the rolling hills and rivers in the metroscape. The floods that forced a deluge of water down the Columbia River between 13 and 17 thousand years ago established the fertile and absorptive landscape of the Willamette Valley. The lush vegetation controlled the regional climate and stabilized the soils, while the thirsty wetlands reduced flood potential, provided habitat, and purified the water. Over geological time, these natural processes have created ideal conditions for humans. The Pacific Northwest was home to some of the most densely populated communities of …

Curriculum Change 2008-2009, Portland State University

Bulletin & Curriculum Change Documents

No abstract provided.

Asymptotic And Numerical Techniques For Resonances Of Thin Photonic Structures, Jay Gopalakrishnan, Shari Moskow, Fadil Santosa

Mathematics and Statistics Faculty Publications and Presentations

We consider the problem of calculating resonance frequencies and radiative losses of an optical resonator. The optical resonator is in the form of a thin membrane with variable dielectric properties. This work provides two very different approaches for doing such calculations. The first is an asymptotic method which exploits the small thickness and high index of the membrane. We derive a limiting resonance problem as the thickness goes to zero, and for the case of a simple resonance, find a first order correction. The limiting problem and the correction are in one less space dimension, which can make the approach …

Hydrologic Response To Extreme Warm And Cold Summers In The Mcmurdo Dry Valleys, East Antarctica, Peter T. Doran, Christopher P. Mckay, Andrew G. Fountain, Thomas H. Nylen, Diane M. Mcknight, Chris Jaros, John E. Barrett

Geography Faculty Publications and Presentations

The meteorological characteristics and hydrological response of an extreme warm, and cold summer in the McMurdo Dry Valleys are compared. The driver behind the warmer summer conditions was the occurrence of down-valley winds, which were not present during the colder summer. Occurrence of the summer down-valley winds coincided with lower than typical mean sea level pressure in the Ross Sea region. There was no significant difference in the amount of solar radiation received during the two summers. Compared to the cold summer, glaciological and hydrological response to the warm summer in Taylor Valley included significant glacier mass loss, and 3- …

An Embarrassment Of Riches: The Enzymology Of Rna Modification, Dirk Iwata-Reuyl

Chemistry Faculty Publications and Presentations

The maturation of transfer RNA (tRNA) involves extensive chemical modification of the constituent nucleosides and results in the introduction of significant chemical diversity to tRNA. Many of the pathways to these modified nucleosides are characterized by chemically complex transformations, some of which are unprecedented in other areas of biology. To illustrate the scope of the field, recent progress in understanding the enzymology leading to the formation of two distinct classes of modified nucleosides, the thiouridines and queuosine, a 7-deazaguanosine, is reviewed. In particular, recent data validating the involvement of several proposed intermediates in the formation of thiouridines are discussed, including …

The Indefinite Metric Of R. Mrugala And The Geometry Of The Thermodynamical Phase Space, Serge Preston, James Vargo

Mathematics and Statistics Faculty Publications and Presentations

We study an indefinite metric G which was introduced by R. Mrugala and is defined on the contact phase space (P, θ) of a homogeneous thermodynamical system. We describe the curvature properties and the isometry group of the metric G. We established an isomorphism of the space (P, θ, G) with the Heisenberg Lie group H_n, endowed with the right invariant contact structure and the right invariant indefinite metric. The lift of the metric G to the symplectization of contact space (P, θ) and its properties are studied. Finally we introduce the "hyperbolic projectivization" of the space …

Traffic Analysis Of Udp-Based Flows In Ourmon, Jim Binkley, Divya Parekh

Computer Science Faculty Publications and Presentations

We present a custom UDP flow tuple with an IP address key and a set of simple related statistical attributes. Attributes are used to calculate a per host metric called the UDP work weight which roughly measures the amount of network noise caused by a host. The work weight is used to produce a near real-time sorted top N report for UDP host tuples. We also present a derived attribute based on an algorithm called the UDP guesstimator. The UDP guesstimator roughly classifies port report hosts into various traffic categories including security threats (DOS/scanning) or P2P hosts based on high …

Locke On Consciousness, Angela M. Coventry, Uriah Kriegel

Philosophy Faculty Publications and Presentations

Locke’s theory of consciousness is often appropriated as a forerunner of present-day Higher-Order Perception (HOP) theories, but not much is said about it beyond that. We offer an interpretation of Locke’s account of consciousness that portrays it as crucially different from current-day HOP theory, both in detail and in spirit. In this paper, it is argued that there are good historical and philosophical reasons to attribute to Locke the view not that conscious states are accompanied by higher-order perceptions, but rather that conscious states constitute perceptions of themselves.

Emperor Has No Clothes: Eu's Cyprus Challenge, Birol A. Yeşilada, Ahmet Sozen

Political Science Faculty Publications and Presentations

In the words of the former UN Secretary General Kofi Annan, “membership of [politically divided] Cyprus in the European Union coupled with Turkey’s membership aspirations has seriously complicated future peace negotiations on the island.” (Hürriyet, June 16, 2006). This is a rather harsh assessment of EU’s Cyprus policy given the fact that membership in the Union would most likely create the optimal conditions for peace and stability between the Greek and Turkish Cypriots. Yet, EU membership of one side at the expense of the other community, seem to have created more obstacles for peace. This paper provides a critical analysis …

Emergence Of Networks In Distance-Constrained Trade, Kumar Venkat, Wayne W. Wakeland

Complex Systems Faculty Publications and Presentations

Long-distance trade has been rapidly increasing in recent years. As traders from around the world exchange goods, they form networks with traders as nodes and transactions as links. We use an agent-based model of a simple artificial economy to examine the emergence of trade networks when the distance between traders matters. Distance can become an issue if fuel for transportation becomes expensive or if greenhouse gas emissions from transportation become a major concern. We model the distance constraint as a transaction cost proportional to the amount of goods traded and the distance that those goods must be transported. We find …

Epistemological Pluralism: Reorganizing Interdisciplinary Research, Thaddeus R. Miller, Timothy D. Baird, Caitlin M. Littlefield, Gary Kofinas, F. Stuart Chapin Iii, Charles L. Redman

Urban Studies and Planning Faculty Publications and Presentations

Despite progress in interdisciplinary research, difficulties remain. In this paper, we argue that scholars, educators, and practitioners need to critically rethink the ways in which interdisciplinary research and training are conducted. We present epistemological pluralism as an approach for conducting innovative, collaborative research and study. Epistemological pluralism recognizes that, in any given research context, there may be several valuable ways of knowing, and that accommodating this plurality can lead to more successful integrated study. This approach is particularly useful in the study and management of social–ecological systems. Through resilience theory's adaptive cycle, we demonstrate how a focus on epistemological pluralism …

Utilization Of Revoicing Based On Learners‘ Thinking In An Inquiry-Oriented Differential Equations Class, Oh Kwon Nam, Mi Kyung Ju, Chris Rasmussen, Karen A. Marrongelle, Jae Hee Park, Kyoung Hee Cho, Jung Sook Park, Jee Hyun Park

Mathematics and Statistics Faculty Publications and Presentations

Researchers of mathematics education are increasingly interested in a teacher's discursive moves, which refer to deliberate actions taken by a teacher to participate in or influence debate and discussion in the mathematics classroom. This study explored one teacher's discursive moves in an undergraduate inquiry-oriented mathematics class. The data for this study come from four class sessions in which students investigated initial value problems as represented by the phase portrait of a system of differential equations. Through the analysis and a review of the literature, we identified four categories of a teacher's discursive moves: revoicing, questioning/requesting, telling, and managing. This report …

The Science Of Persuasion In Recent Discourse On T.R. Malthus: An Exercise In The Analysis Of Rhetoric In Economics, Laila Winner

Economics Undergraduate Honors Theses

Of all the dour portraits lining the august halls of Economics, it is that of Thomas Robert Malthus which seems perhaps to scowl the most grimly. Describing an approach or policy as Malthusian in everyday conversation conjures a host of disturbing images, bare fields and squalling babies chief among them. Such allusions provoke even stronger reactions within the discipline Malthus helped to found, ranging from Keynes's fervent championship to the sneering dismissal of Samuelson. Neither the more famous Smith nor Ricardo nor even Marx can claim to have gained in their lives what the comparatively less prolific Reverend did with …

Crossing Borders, Building Bridges, Gayle Y. Thieman

Education Faculty Publications and Presentations

This article is derived from the presidential address delivered at the NCSS Annual Meeting in San Diego on November 30, 2007.

Through collaboration and involvement, we can meet the five critical challenges facing social studies educators today.

Invasive Predator, Bythotrephes, Has Varied Effects On Ecosystem Function In Freshwater Lakes, Angela L. Strecker, Shelley E. Arnott

Environmental Science and Management Faculty Publications and Presentations

Bythotrephes longimanus is an invertebrate predator that has invaded the North American Great Lakes and a number of inland lakes, where it preys on crustacean zooplankton. We examined the effect of Bythotrephes on two measures of ecosystem function during a four month observational study of freshwater lakes on the boreal shield. Bythotrephes-invaded lakes had significantly lower epilimnetic zooplankton abundance and production compared to reference lakes. On average, Bythotrephes consumed 34% ofzooplankton production when it was present in lakes. There was some evidence of changes in the timing of zooplankton production, as well as shifts to cooler, less productive habitats, which …

Superior Adaptation To Drought In Rubus Armeniacus (Himalayan Blackberry) In Northwest Oregon, J. Alan Yeakley, Joshua S. Caplan

Environmental Science and Management Faculty Publications and Presentations

Despite the status Rubus armeniacus (Himalayan blackberry) has as one of the most prolific and damaging plant invaders in the Pacific Northwest, we know little about the role of water relations in its success. The information available on invasive blackberry water relations (Fotelli et al. 2001; McDowell and Turner 2002) suggests that an ability to avoid water stress has been critically important to their proliferation in regions with Mediterranean climates (Amor et al. 1998). We had two objectives regarding the role of water relations in the invasive success of R. armeniacus:

Objective 1. Determine if R. armeniacus is better adapted …

Differential Effects Of Understory And Overstory Gaps On Tree Regeneration, Brian Beckage, Brian D. Kloeppel, J. Alan Yeakley, Sharon F. Taylor, David C. Coleman

Environmental Science and Management Faculty Publications and Presentations

Gaps in the forest canopy can increase the diversity of tree regeneration. Understory shrubs also compete with tree seedlings for limited resources and may depress tree recruitment. We compared effects of shrub removal and canopy windthrow gaps on seedling recruitment and understory resource levels. Shrub removal, with the canopy left intact, was associated with increased levels of understory light and soil moisture and coincided with increased species richness and diversity of tree regeneration compared to both control plots and canopy gaps. Canopy windthrow gaps, however, resulted in a more than 500 fold increase in soil nitrate concentrations, and seedling growth …

Engaging Recreational Fishers In Management And Conservation: Global Case Studies, Elise F. Granek, Elizabeth M.P. Madin, M. A. Brown, Will F. Figueira, Darren S. Cameron, Zeb Hogan, Gerry Kristianson, Pierre De Villiers, Jack E. Williams, John R. Post, S. Zahn, R. Arlinghaus

Environmental Science and Management Faculty Publications and Presentations

Globally, the number of recreational fishers is sizeable and increasing in many countries. Associated with this trend is the potential for negative impacts on fish stocks through exploitation or management measures such as stocking and introduction of non-native fishes. Nevertheless, recreational fishers can be instrumental in successful fisheries conservation through active involvement in, or initiation of, conservation projects to reduce both direct and external stressors contributing to fishery declines. Understanding fishers’ concerns for sustained access to the resource and developing methods for their meaningful participation can have positive impacts on conservation efforts. We examined a suite of case studies that …

Rapid Assessment Of 2008-2012 Highway Development Projects In Region 6: Threats And Opportunities To Terrestrial Wildlife Resources, Sandra L. Jacobson, Catherine E. De Rivera, Kathleen Armstrong, Rebecca Aaby, Nadia Jones

Environmental Science and Management Faculty Publications and Presentations

Summaries of Highway Development Projects in Region 6 National Forests.

This document contains a summary of higher complexity projects selected for their interest to line officers and resource managers. These projects represent not only the current Statewide Transportation Improvement Plan (STIP) projects but also a sample of the types of projects that will be on future STIPs. Thus, readers are urged to glance at the tracking tools and narratives for all forests to gain a quick glimpse of the types of projects potentially facing each forest. The summary has extracted brief information on project locations and types, the program year …

Nutrient Uptake By Intact And Disturbed Roots Of Loblolly Pine Seedlings, Melissa S. Lucash, Ruth D. Yanai, J. Devereux Joslin

Environmental Science and Management Faculty Publications and Presentations

Most measurements of nutrient uptake use either hydroponic systems or soil-grown roots that have been disturbed by excavation. The first objective of this study was to test how root excavation affects nitrate uptake. Rates of NO3− uptake by mycorrhizal loblolly pine (Pinus taeda L.) seedlings were measured in intact sand-filled columns, hydroponics, and disturbed sand-filled columns. Total nitrate uptake in intact sand-filled columns was higher than in disturbed columns, indicating that disturbance lowers uptake. Transferring plants from the sand-filled columns to hydroponics had little effect on NO3− uptake beyond delaying uptake for an hour. The second objective of this study …

Inventory And Mapping Of Aquatic Plants At Lake Roosevelt National Recreation Area, Mark D. Sytsma, Rich Miller

Center for Lakes and Reservoirs Publications and Presentations

Lake Roosevelt is a large reservoir in northeast Washington State formed by the Grand Coulee Dam. The reservoir, which inundates portions of the Columbia River, the Spokane River, and other rivers and streams, is the focus of the Lake Roosevelt National Recreation Area (LARO) that is managed by the National Park Service. LARO encompasses 100,390 acres (40,625 ha) and includes significant cultural and recreational resources. The surface area, volume, and shoreline length of Lake Roosevelt at full pool is 82,691 acres (33,490 ha), 9.41 × 10¹⁰ acre-ft (1.16 × 10¹⁰ m³) (Nigro et. al. 1981), and …

Staying Within The Margins: The Educational Stories Of First-Generation, Low-Income College Students, Diane Lyn Cole

Dissertations and Theses

his research addressed educational persistence among first-generation, low-income college students. The educational paths of 22 first-generation, low-income undergraduate students attending a large, urban university in the Northwest region of the United States were examined through a narrative framework. Half of the participants had persisted from year one to year two, and the other half left the university after their first year. Analytic procedures consisted of thematic qualitative coding, an analysis of student trajectories over educational histories, and the reconstruction of narrative stories. Data were used to examine: (1) How first-generation, low-income students understood and described their journey through their first …

Multigrid Convergence For Second Order Elliptic Problems With Smooth Complex Coefficients, Jay Gopalakrishnan, Joseph E. Pasciak

Mathematics and Statistics Faculty Publications and Presentations

The finite element method when applied to a second order partial differential equation in divergence form can generate operators that are neither Hermitian nor definite when the coefficient function is complex valued. For such problems, under a uniqueness assumption, we prove the continuous dependence of the exact solution and its finite element approximations on data provided that the coefficients are smooth and uniformly bounded away from zero. Then we show that a multigrid algorithm converges once the coarse mesh size is smaller than some fixed number, providing an efficient solver for computing discrete approximations. Numerical experiments, while confirming the theory, …

Polynomial Extension Operators. Part I, Leszek Demkowicz, Jay Gopalakrishnan, Joachim Schöberl

Mathematics and Statistics Faculty Publications and Presentations

In this series of papers, we construct operators that extend certain given functions on the boundary of a tetrahedron into the interior of the tetrahedron, with continuity properties in appropriate Sobolev norms. These extensions are novel in that they have certain polynomial preservation properties important in the analysis of high order finite elements. This part of the series is devoted to introducing our new technique for constructing the extensions, and its application to the case of polynomial extensions from H^½(∂K) into H¹(K), for any tetrahedron K.

A Mixed Method For Axisymmetric Div-Curl Systems, Dylan M. Copeland, Jay Gopalakrishnan, Joseph E. Pasciak

Mathematics and Statistics Faculty Publications and Presentations

We present a mixed method for a three-dimensional axisymmetric div-curl system reduced to a two-dimensional computational domain via cylindrical coordinates. We show that when the meridian axisymmetric Maxwell problem is approximated by a mixed method using the lowest order Nédélec elements (for the vector variable) and linear elements (for the Lagrange multiplier), one obtains optimal error estimates in certain weighted Sobolev norms. The main ingredient of the analysis is a sequence of projectors in the weighted norms satisfying some commutativity properties.

Uniform Materials And The Multiplicative Decomposition Of The Deformation Gradient In Finite Elasto-Plasticity, Vincenzo Ciancio, Marina Dolfin, Mauro Francaviglia, Serge Preston

Mathematics and Statistics Faculty Publications and Presentations

In this work we analyze the relation between the multiplicative decomposition F = F e F p of the deformation gradient as a product of the elastic and plastic factors and the theory of uniform materials. We prove that postulating such a decomposition is equivalent to having a uniform material model with two configurations – total φ and the inelastic φ1. We introduce strain tensors characterizing different types of evolutions of the material and discuss the form of the internal energy and that of the dissipative potential. The evolution equations are obtained for the configurations (φ, φ1) and the material …

On The Spectra Of Certain Directed Paths, Carlos Martins Da Fonseca, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

We describe the eigenpairs of special kinds of tridiagonal matrices related to problems on traffic on a one-lane road. Some numerical examples are provided.

The Use And Interpretation Of The Batería Iii With U.S. Bilinguals, Julie Esparza Brown

Dissertations and Theses

Within each classroom, many children excel academically while others struggle. Some students' difficulties are such that they require placement into educational programs different from grade level core and perhaps delivered outside of general education classrooms. For many, special education programs are the lifeline to reach their innate potential. For others misplaced into special education, their opportunities may be truncated. For the past 40 years (Dunn, 1968), disproportionate representation of minority children in some disability categories has been a problem. Educators commonly ask "Is a child's difficulties due to language differences or a learning disability?" One key area of confusion relates …