Digital Commons Network^™

Transgenic Crops: An Environmental Assessment, David E. Ervin, Sandra S. Batie, Rick Welsh, Chantal L. Carpentier, Jacqueline I. Fern, Nessa J. Richman, Mary A. Schulz

Economics Faculty Publications and Presentations

The report focuses on the environmental impacts of transgenic crops, and covers biosafety regulations in the US and EU, intellectual property rights, and market and trade developments.

Shubnikov–De Haas Effect In The Superconducting State Of An Organic Superconductor, J. Wosnitza, S. Wanka, J. Hagel, R. Häussler, H. V. Löhneysen, J. A. Schlueter, U. Geiser, P. G. Nixon, Rolf Walter Winter, Gary L. Gard

Chemistry Faculty Publications and Presentations

We report the observation of Shubnikov–de Haas (SdH) oscillations in the mixed state of the organic superconductor β″-(BEDT-TTF)₂SF₅CH₂CF₂SO₃ (Tc≈4.4K). At low temperatures the SdH oscillations persist clearly below the upper critical field Bc₂(0)≈3.6 T almost down to the field where the resistivity vanishes. Rather unusually, no additional damping of the SdH-signal amplitude — as well as of the de Haas–van Alphen amplitude — is observed in the superconducting state. This indicates that the damping in the vortex state of this quasi-two-dimensional superconductor is different in character to that observed for most three-dimensional materials.

Application Of Tree-Structured Regression For Regional Precipitation Prediction Using General Circulation Model Output, Xiangshang Li, David J. Sailor

Mechanical and Materials Engineering Faculty Publications and Presentations

This study presents a tree-structured regression (TSR) method to relate daily precipitation with a variety of free-atmosphere variables. Historical data were used to identify distinct weather patterns associated with differing types of precipitation events. Models were developed using 67% of the data for training and the remaining data for model validation. Seasonal models were built for each of 2 US sites: San Francisco, California, and San Antonio, Texas. The average correlation between observed and simulated daily precipitation data series is 0.75 for the training set and 0.68 for the validation set. Relative humidity was found to be the dominant variable …

Lava And Ice Interaction At Stratovolcanoes: Use Of Characteristic Features To Determine Past Glacial Extents And Future Volcanic Hazards, David T. Lescinsky, Jonathan H. Fink

Geology Faculty Publications and Presentations

Structures resulting from lava and ice interaction are common at glaciated stratovolcanoes. During summit eruptions at stratovolcanoes, meltwater is produced and travels freely down steep slopes and thin permeable valley glaciers, eroding the ice and enlarging preexisting glacial drainages. As a result, in this environment have produced few catastrophic floods. Lava flowing into the open channels and voids in the glaciers becomes confined and grows thicker, filling the available space and producing steep-sided bodies with smooth, bulbous contact surfaces. Quenching of lava against ice or by water forms small-scale features such as tensional fractures and glass. As the amount of …

Structure And Phase Transitions Of The 6, 6-Cyclopropane Isomer Of C_ {61} H_ {2}, M. R. Stetzer, Paul A. Heiney, Peter W. Stephens, R. E. Dinnebier, Q. Zhu, Andrew R. Mcghie, Robert M. Strongin, B. M. Brandt, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

We have used x-ray powder diffraction and differential scanning calorimetry to study the crystalline structures and thermal behavior of the 6,6-cyclopropane isomer of C₆₁H₂. At room temperature, the C₆₁H₂ cyclopropane molecules, like those of the 6,5-annulene isomer and C₆₀O epoxide, are orientationally disordered and crystallize on a face-centered-cubic lattice such that their methylene groups are statistically disordered among the octahedral voids. Unlike 6,5−C₆₁H₂ and C₆₀O, the low-temperature structure is not Pa3¯, but rather a low-symmetry orthorhombic lattice in which a≈b

Dependence Among Spacings, Baha-Eldin Khaledi, Subhash C. Kochar

Mathematics and Statistics Faculty Publications and Presentations

In this paper, we study the dependence properties of spacings. It is proved that if X₁,..., X_n are exchangeable random variables which are TP₂ in pairs and their joint density is log-convex in each argument, then the spacings are MTP₂ dependent. Next, we consider the case of independent but nonhomogeneous exponential random variables. It is shown that in this case, in general, the spacings are not MTP₂ dependent. However, in the case of a single outlier when all except one parameters are equal, the spacings are shown to be MTP₂ dependent and, hence, …

The Cracker Patch Choice: An Analysis Of Post Hoc Security Techniques, Crispin Cowan, Heather Hinton, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

It has long been known that security is easiest to achieve when it is designed in from the start. Unfortunately, it has also become evident that systems built with security as a priority are rarely selected for wide spread deployment, because most consumers choose features, convenience, and performance over security. Thus security officers are often denied the option of choosing a truly secure solution, and instead must choose among a variety of post hoc security adaptations. We classify security enhancing methods, and compare and contrast these methods in terms of their effectiveness vs. cost of deployment. Our analysis provides practitioners …

2000 Summer Commencement Program, Daniel O. Bernstine

Commencement Archives 2000-09

The program for the PSU Summer Commencement ceremony on August 12, 2000.

Theoretical Basis For The Ce-Qual-W2 River Basin Model, Scott A. Wells, Thomas M. Cole

Civil and Environmental Engineering Faculty Publications and Presentations

The primary objective of this research is to integrate a riverine model into the existing W2 code that would provide the capability for modeling entire watersheds. This task was accomplished by the following steps:

• Formal derivation of governing equations and solution algorithm with general channel slope

• Detailed analysis of algorithm for linking branches and smooth implementation of boundary conditions between branches

• Algorithm development and changes to basic model code (including branch definitions with slope, slope correction to solution algorithm, transfer of momentum between internal branches)

These tasks were performed with the following constraints and initiatives:

• Utilize …

An Efficient Method For Band Structure Calculations In 3d Photonic Crystals, David C. Dobson, Jay Gopalakrishnan, Joseph E. Pasciak

Mathematics and Statistics Faculty Publications and Presentations

A method for computing band structures for three-dimensional photonic crystals is described. The method combines a mixed finite element discretization on a uniform grid with a fast Fourier transform preconditioner and a preconditioned subspace iteration algorithm. Numerical examples illustrating the behavior of the method are presented.

Ce-Qual-W2, Version 3, Scott A. Wells, Thomas M. Cole

Civil and Environmental Engineering Faculty Publications and Presentations

CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic code supported by the U.S. Army Engineer Research and Development Center (Cole and Buchak 1995). The model has been widely applied to stratified surface water systems such as lakes, reservoirs, and estuaries and computes water levels, horizontal and vertical velocities, temperature, and 21 other water quality parameters (such as dissolved oxygen, nutrients, organic matter, algae, pH, the carbonate cycle, bacteria, and dissolved and suspended solids). A typical model grid is shown in Figure 1 where the vertical axis is aligned with gravity.

This technical note documents the development of CE-QUAL-W2, Version 3, …

Simpson's Paradox Can Emerge From The N-Player Prisoner's Dilemma: Implications For The Evolution Of Altruistic Behavior, Jeffrey Alan Fletcher, Martin Zwick

Complex Systems Faculty Publications and Presentations

Simulations of the n-player Prisoner’s Dilemma in multiple populations reveal that Simpson’s paradox can emerge in such game-theoretic situations. The relative proportion of cooperators can decrease in each separate sub-population, while the proportion of cooperators in the total population can nonetheless increase, at least transiently. Factors that determine the longevity of this effect are under investigation. The increase of altruistic behavior exhibited in these simulations is not based on reciprocal altruism, as there are no strategies conditional on other players’ past actions, nor does it depend on kin selection via inclusive fitness, as there are no genes. This model is …

Understanding Imperfection, Martin Zwick

Complex Systems Faculty Publications and Presentations

Because of their inherent abstraction, systems ideas are not themselves sufficient for gaining scientific knowledge or solving practical problems, but they can be a source of insights into the universality of imperfection, insights which can contribute to a new scientific world view. Systems theory offers a metaphysics, or more precisely an ontology, of imperfection. Through it, we can heed Spinoza's injunction, “Not to lament, not to curse, but to understand.”

2000 Commencement Program, Vera Katz

Commencement Archives 2000-09

The program for the PSU Commencement ceremony on June 11, 2000.

Mayor of Portland, the Honorable Vera Katz, delivered the commencement address and was awarded an honorary doctorate by PSU President Dan Bernstine.

Sym Bowl Update: Encouraging And Recognizing Student Proficiency In System Dynamics Modeling, Wayne W. Wakeland

Complex Systems Faculty Publications and Presentations

The judging criteria and modeling process guidelines for the SyM Bowl modeling competition are briefly reviewed. Prize-winning student models from previous SyM Bowls are then discussed in order to show how the students and their teachers appear to have interpreted the criteria and process guidelines. The strengths and limitations of the selected student models, especially the basic model structure & logic, and the process they used to build the model, as evidenced in the reports they submitted, are then presented.

The paper then considers how the criteria and process guidelines may or may not have influenced the students, followed by …

A Framework For Gis-T Data Sharing, Kenneth Dueker, J. Allison Butler

Center for Urban Studies Publications and Reports

This paper develops a framework and principles for sharing of transportation data. The framework is intended to clarify roles among participants, data producers, data integrators, and data users. The principles are intended to provide guidance for the participants. Both the framework and the principles are based on an enterprise GIS-T data model that defines relations among transportation data elements. The data model guards against ambiguities and provides a basis for the development of the framework and principles for sharing of transportation data. There are two central principles. First is the uncoupling of graphics, topology, position, and characteristics. Second is the …

Gaussian Beams In Hollow Metal Waveguides, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

Various families of Gaussian beams have been explored previously to represent the propagation of nearly plane electromagnetic waves in media having at most quadratic transverse variations of the index of refraction and the gain or loss in the vicinity of the beam. However, such beams cannot directly represent the wave solutions for propagation in planar or rectangular waveguides, and sinusoidal mode functions are more commonly used for such waveguides. On the other hand, it is also useful to consider the possibility of recurring Gaussian beams that have an approximately Gaussian transverse profile at certain distinct planes along the propagation path. …

Aspects Of Information Flow, Andrew P. Black, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Along with our colleagues at the Oregon Graduate Institute and Georgia Institute of Technology, we have recently been experimenting with real-rate systems, that is, systems that are required to move data from one place to another at defined rates, such as 30 items per second. Audio conferencing or streaming video systems are typical: they are required to deliver video or audio frames from a source (a server or file system) in one place to a sink (a display or a sound generator) in another; the frames must arrive periodically, with constrained latency and jitter. We have successfully built such systems …

Establishing The Inundation Distance And Overtopping Height Of Paleotsunami From The Late-Holocene Geologic Record At Open-Coastal Wetland Sites, Central Cascadia Margin, Robert B. Schlichting

Dissertations and Theses

Mapping and stratigraphic investigations of back barrier, open-coastal plain sites have been used to establish minimum inundation distances and wave heights of tsunami produced by great subduction zone earthquakes in the central Cascadia margin. Cascadia tsunami deposits have been reported for many coseismic subsidence events in bay marsh settings where tidal-channel features focus tsunami energy. Variable magnitude (8.5±0.5 Mw), frequency (500±300 yr recurrence), and rupture geometry produce widely varying computer model outcomes for Cascadia tsunami inundation. The results presented in this thesis provide specific quantitative data regarding tsunami inundation at the open coast.

Anomalous sand sheets that have been characterized …

A Visual Interaction Of Rational And Intuitive Processes, Priscilla Hanson

Dissertations and Theses

The paintings in this exhibition are an investigation of the dichotomy between rational and intuitive processes. The scope ranges from a purely historical perspective to include personal history as well. The work references ancient mythologies and the ordering systems that humans have created to explain the world around them as an expression of rational processes. The objects and symbols used derive from my interest in archaeology, mythology, astrology, and astronomy of the ancient world. Most of the surface on my paintings is unstructured, consisting of loosely applied layers of paint and subtly shifting colors. Surfaces are built up through a …

Structured Web Databases, Shuang Li

Dissertations and Theses

Recent research has focused on the cooperation of web server and database server software in the deployment of data-intensive web sites. That work has focused either on storing data in a database that can be used to generate the contents of a web site, or on providing interfaces and gateways to enable queries to be invoked from web pages and executed at external database servers.

This thesis describes the implementation of a prototype of the Data Web system that is being implemented at Portland State University. With Data Web, a user can embed in a web page virtual tables that …

“The Way Of The Scientist Deepens Beauty By Increasing Understanding”: Teaching Physics As An Aesthetic Form, Claudine Indigo Kavanagh

Dissertations and Theses

Educators have struggled to find an appropriate and efficacious method to engage students of science in their classrooms and lecture halls, This investigation presents a theoretical foundation for the use of aesthetic criteria when teaching physics in high school or undergraduate settings and suggests that this may be an effective learning tool. The relationship between science aesthetics and science literacy is pursued here. Included in this study are discussions of the applications of aesthetic judgement by theoretical physicists in the 20th century and and methods for bringing a dialogue concerning natural philosophy and beauty in the science classroom. While many …

Comparative Thermal-Expansion Study Of Β″-(Et)2sf5ch2cf2so3 And Κ-(Et)2cu(Ncs)2: Uniaxial Pressure Coefficients Of Tc And Upper Critical Fields, J. Müller, M. Lang, F. Steglich, J. A. Schlueter, A. M. Kini, U. Geiser, Javid Mohtasham, Rolf Walter Winter, Gary L. Gard, T. Sasaki, N. Toyota

Chemistry Faculty Publications and Presentations

We report high-resolution measurements of the coefficient of thermal expansion, α=l⁻¹ x (δl/δΤ), on single crystals of the organic superconductors β″-(ET)₂SF₅CH₂CF₂SO₃ and κ-(ET)₂Cu(NCS)₂. For both salts we find large and highly anisotropic phase-transition anomalies at Tc. Combining these data with literature results on the specific heat via the Ehrenfest relation, the uniaxial pressure coefficients of Tc can be determined. Most remarkably, a strikingly similar in-plane vs out-of-plane anisotropy is found for both compounds: the strong suppression of Tc observed in hydrostatic-pressure experiments is dominated by a huge negative uniaxial stress effect perpendicular to the conducting planes. Therefore we expect that …

Simple Model For Mixing At Accelerated Fluid Interfaces With Shear And Compression, John D. Ramshaw

Physics Faculty Publications and Presentations

A simple model was recently described for predicting linear and nonlinear mixing at an unstable planar interface between two fluids of different density subjected to an arbitrary time-dependent variable acceleration history [J. D. Ramshaw, Phys. Rev. E 58, 5834 (1998)]. Here we generalize this model to include the Kelvin-Helmholtz (KH) instability resulting from a tangential velocity discontinuity delta u, as well as the effects of a uniform anisotropic compression or expansion of the mixing layer as a whole. The model consists of a second-order nonlinear ordinary differential equation of motion for the half-width h of the mixing layer. This equation …

Comment On "Dynamically Maintained Steady-State Pressure Gradients", Todd L. Duncan

Center for Science Education Publications and Presentations

Sheehan [Phys. Rev. E 57, 6660 (1998)] recently discussed the possibility of establishing a dynamically maintained, steady-state pressure gradient in a gas filling a cavity. In this Comment it is pointed out that the pressure gradients in such a system, if attainable in the laboratory, could be used to violate the second law of thermodynamics.

A Longitudinal Assessment Of Temperament In Octopus Bimaculoides, David Loyd Sinn

Dissertations and Theses

Cephalopods, including Octopus spp., are highly intelligent molluscs that play major roles in many marine food webs, both as top-level feeders (Ambrose, 1984) as well as by constituting a major source of protein for the animals above them (Lang, Hochberg, Ambrose, & Engle, 1997). They also are fascinating organisms for behavioral studies, with elaborate repertoires of behavior based on plasticity and learning (Wells, 1962a; 1962b; 1978) which in complexity rivals that of the vertebrates. The study of individual differences in behavior is a facet of behavioral research that has recently gained attention in the literature (Gosling & John, 1999). Traditionally, …

Multiple Source Pools And Dispersal Barriers For Galápagos Plant Species Distribution, J. Alan Yeakley, John F. Weishampel

Environmental Science and Management Faculty Publications and Presentations

We reexamined geographic factors explaining the number of plant species on islands in the Galápagos Archipelago. We hypothesized that plant species richness (S) was related to the number of source pools and that plant species dispersal preferentially followed direct, oceanic pathways. To test different dispersal pathways from multiple source pools, the total number of islands within a given dispersal radius (i) was posed as the sum of the number of line-of-sight islands (C_i) and of the number of islands without line-of sight connection (B_i). In partial regression analyses, controlling for nearest island area (A₂) …

Two-Dimensional Fermi Liquid With Fixed Chemical Potential, J. Wosnitza, S. Wanka, J. Hagel, E. Balthes, N. Harrison, J. A. Schlueter, A. M. Kini, U. Geiser, Javid Mohtasham, Rolf Walter Winter, Gary L. Gard

Chemistry Faculty Publications and Presentations

de Haas-van Alphen measurements made on the organic metal β″-(ET)₂SF₅CH₂CF₂SO₃ reveal the existence of an ideal two-dimensional (2D) Fermi surface, but rather than having the conventional sawtooth wave form that is normally observed in all other 2D electron gases, instead, an ‘‘inverse sawtooth’’ wave form is observed, which is to be expected when the chemical potential is pinned at a constant value. While this proves the existence of the theoretically predicted quasi-one-dimensional band, it further implies that this band has an exceptionally large density of states.

Smart For One, Dumb For All. Review Of: Luxury Fever: Why Money Fails To Satisfy In An Era Of Excess By Robert H. Frank, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Book review of Luxury Fever: Why Money Fails to Satisfy in an Era of Excess. Robert H. Frank. Free Press, New York, 1999.

Portable Wood Burning Field Stove: United States Patent, John B. Hall

Economics Faculty Publications and Presentations

The ornamental design for a portable wood burning field stove.