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Articles 3301 - 3330 of 3797
Full-Text Articles in Physical Sciences and Mathematics
Effects Of The Cardioprotective Drugs Dexrazoxane And Adr-925 On Doxorubicin Induced Ca2+-Release From The Sarcoplasmic Reticulum, Thomas Andreas Herzinger
Effects Of The Cardioprotective Drugs Dexrazoxane And Adr-925 On Doxorubicin Induced Ca2+-Release From The Sarcoplasmic Reticulum, Thomas Andreas Herzinger
Dissertations and Theses
The sarcoplasmic reticulum is the intramuscular organelle responsible for the regulation of cytoplasmic calcium levels in muscle. This thesis investigates the effects of the cardioprotective drug, dexrazoxane, and its metabolite ADR-925 on doxorubicin induced calcium release from skeletal sarcoplasmic reticulum. Doxorubicin is a widely used antineoplastic agent. One of the major side effects of doxorubicin usage is chronic cardiotoxicity. Doxorubicin is a potent activator of the calcium release mechanism from the SR. The interaction between doxorubicin and the calcium release channel has been proposed as the possible underlying mechanism behind cardiotoxicity. A short overview of different hypotheses describing doxorubicin induced …
Ecological Economics: Reintegrating The Study Of Humans And Nature, Robert Costanza
Ecological Economics: Reintegrating The Study Of Humans And Nature, Robert Costanza
Institute for Sustainable Solutions Publications and Presentations
Ecological economics is a transdisciplinary effort to link the natural and social sciences broadly, and especially ecology and economics. The goal is to develop a deeper understanding of the complex linkages between ecological and economic systems, and to use that understanding to develop effective policies that will lead to a world that is ecologically sustainable, has a fair distribution of resources (both among groups and generations of humans and between humans and other species), and efficiently allocates scarce resources including natural capital. This will require new approaches that are comprehensive, adaptive, integrative, multi-scale, and pluralistic, and that acknowledge the huge …
Multimedia Applications Require Adaptive Cpu Scheduling, Veronica Baiceanu, Crispin Cowan, Dylan Mcnamee, Calton Pu, Jonathan Walpole
Multimedia Applications Require Adaptive Cpu Scheduling, Veronica Baiceanu, Crispin Cowan, Dylan Mcnamee, Calton Pu, Jonathan Walpole
Computer Science Faculty Publications and Presentations
CPU scheduling and admission testing for multimedia applications have been extensively studied, and various solutions have been proposed using assorted simplifying assumptions. However, we believe that the complexity and dynamic behavior of multimedia applications and systems make static solutions hard to apply in real-world situations. We are analyzing the difficulties that arise when applying the rate-monotonic (RM) scheduling algorithm and the corresponding admission tests for CPU management, in the context of real multimedia applications running on real systems. RM requires statically predictable, periodic workloads, and while multimedia applications appear to be periodic, in practice they exhibit numerous variabilities in workload. …
Effective And Appropriate Use Of Controlled Experimentation In Software Development Research, Mark Alan Johnson
Effective And Appropriate Use Of Controlled Experimentation In Software Development Research, Mark Alan Johnson
Dissertations and Theses
Although there is a large body of research and publication on software development, only a limited amount of this work includes empirical demonstration of its effectiveness. Yet, it is this empirical understanding which will help move software development from a craft to an engineering discipline. Of the empirical methods for research, controlled experiments are the most commonly thought of in scientific studies, and yet the least used to study software development.
This thesis begins with a brief review of the different empirical methods commonly used to study software development. This review provides a quick introduction to each empirical method, compares …
Impact Of Groundwater Contamination In East Multnomah County On The Interlachen Community, Scott A. Wells, Shuguang Li, Marvin Beeson, Michael L. Cummings, Richard Pratt, Robert Leslie Annear, Karann Brandt
Impact Of Groundwater Contamination In East Multnomah County On The Interlachen Community, Scott A. Wells, Shuguang Li, Marvin Beeson, Michael L. Cummings, Richard Pratt, Robert Leslie Annear, Karann Brandt
Civil and Environmental Engineering Faculty Publications and Presentations
The Friends of Blue and Fairview Lake through the Environmental Protection Agency (EPA) Technical Assistance Grant (TAG) program contracted with Portland State University faculty and staff to provide an independent review of the groundwater contamination problem at the Boeing-Cascade site in East Multnomah County. An independent consultant, Karann Brandt, of PRC Environmental Management, Inc., was also assisting the panel with the review.
The region of groundwater contamination is a 2.5 square mile region bounded by NE Halsey Blvd. to the Columbia River and NE 178th to NE 223rd (see Figure 1). The groundwater contamination is primarily of volatile organic compounds …
Design Of A Two-Chamber-No₂-Fluorescence-Cell, Volker Schmid
Design Of A Two-Chamber-No₂-Fluorescence-Cell, Volker Schmid
Dissertations and Theses
Nitrogen oxides control the photochemical production of ozone O3 in the lower atmosphere and influence the concentration of the hydroxyl radical HO in the troposphere. As an important member of the nitrogen oxide family, NO₂ plays a significant role in serving as the only known source of ozone (through photolysis) in the lower atmosphere and as sink for HO via formation of nitric acid. Therefore, accurate measurements of nitrogen dioxide are essential for the understanding of the processes that determine the distribution of tropospheric ozone and for assessing the impact of human activity on the troposphere.
Although reliable and …
Calibration Of A Ccd Camera And Correction Of Its Images, Armin Rest
Calibration Of A Ccd Camera And Correction Of Its Images, Armin Rest
Dissertations and Theses
Charge-Coupled-Device (CCD) cameras have opened a new world in astronomy and other related sciences with their high quantum efficiency, stability, linearity, and easy handling. Nevertheless, there is still noise in raw CCD images and even more noise is added through the image calibration process. This makes it essential to know exactly how the calibration process impacts the noise level in the image. The properties and characteristics of the calibration frames were explored. This was done for bias frames, dark frames and flat-field frames at different temperatures and for different exposure times.
At first, it seemed advantageous to scale down a …
Independent Center, Independent Electron Approximation For Dynamics Of Molecules And Clusters, James H. Mcguire, Jack C. Straton, J. Wang, Y. D. Wang, O. L. Weaver, S. E. Corchs, R. D. Rivarola
Independent Center, Independent Electron Approximation For Dynamics Of Molecules And Clusters, James H. Mcguire, Jack C. Straton, J. Wang, Y. D. Wang, O. L. Weaver, S. E. Corchs, R. D. Rivarola
Physics Faculty Publications and Presentations
A formalism is developed for evaluating probabilities and cross sections for multiple-electron transitions in scattering of molecules and clusters by charged collision partners. First, the molecule is divided into subclusters each made up of identical centers (atoms). Within each subcluster coherent scattering from identical centers may lead to observable phase terms and a geometrical structure factor. Then, using a mean field approximation to describe the interactions between centers we obtain {ital A}{sub {ital I}}{approximately}{summation}{sub {ital k}}{product}{sub {ital ke}}{sup {ital i}{delta}{sup {ital k}}{sub {ital I}}}{ital A}{sub {ital Ik}}. Second, the independent electron approximation for each center may be obtained by neglecting …
Quantification Of Extraterrestrial Lava Flow Effusion Rates Through Laboratory Simulations, Tracy K.P. Gregg, Jonathan H. Fink
Quantification Of Extraterrestrial Lava Flow Effusion Rates Through Laboratory Simulations, Tracy K.P. Gregg, Jonathan H. Fink
Geology Faculty Publications and Presentations
We have used carefully controlled laboratory simulations to develop a model which relates lava flow morphology to effusion rate and rheology. Through comparisons with measured and estimated eruption rates on Earth, this approach allows us to constrain eruptive styles and compositions of extraterrestrial lava flows. By applying this model to lava flows on the Moon, Mars and Venus, we have determined that all the common flow morphologies (domes, folds and levees) on these planets could have been produced by basalt-like or andesite-like lavas through either continuous or episodic emplacement. The presence of more evolved magma compositions on other planets is …
Distribution Coefficients Of Ionized And Un-Ionized Halogenated Phenols In An Octanol-Water System And Their Relationship To Molecular Structure, Sven Hensler
Dissertations and Theses
Life supporting biological membranes are barriers to toxic chemicals. One of the factors determining the toxicity of chemical compounds is their distribution between membranes and their an environment. An octanol-water system is frequently used as a model for biological membranes to estimate the toxic potency of environmental pollutants. The distribution of a chemical between the octanol and the water phase is described by the octanol-water partition coefficient KOW. This study is concerned with the relationship between KOW and the molecular structure of the toxic chemical.
In the study the following trihalophenols were included: 2,4,6-trifluorophenol (TriFP), 2,4,6-trichlorophenol (TriCP); …
Correlation Of The Upper Ellensburg Formation With The Old Scab Mountain Eruptive Center, East-Central Cascade Range, Washington, Christopher Charles Humphrey
Correlation Of The Upper Ellensburg Formation With The Old Scab Mountain Eruptive Center, East-Central Cascade Range, Washington, Christopher Charles Humphrey
Dissertations and Theses
The Ellensburg Formation, preserved in the Nile basin 50 km northwest of Yakima, Washington, consists of a series of middle to late Miocene epiclastic and pyroclastic rock assemblages rich in porphyritic hornblende-biotite dacite. Geochemical, petrographic, and stratigraphic correlations indicate that Old Scab Mountain, a dacite porphyry intrusion, located at the western margin of the basin (lat. 46°53'30", long. 121°13'00"), is the probable source for much of the upper Ellensburg volcaniclastic material in the basin. The dacite intrusion exposed at Old Scab Mountain was emplaced at depths of 1 to 3 km and underlaid a now eroded volcanic edifice. This volcanic …
Structure, Dynamics, And Phase Transitions In The Fullerene Derivatives C_{60}O And C_{61}H_{2}, C. Meingast, G. Roth, L. Pintschovius, R. H. Michel, C. Stoermer, M. M. Kappes, Paul A. Heiney, Laurent Brard, Robert M. Strongin, Amos B. Smith Iii
Structure, Dynamics, And Phase Transitions In The Fullerene Derivatives C_{60}O And C_{61}H_{2}, C. Meingast, G. Roth, L. Pintschovius, R. H. Michel, C. Stoermer, M. M. Kappes, Paul A. Heiney, Laurent Brard, Robert M. Strongin, Amos B. Smith Iii
Chemistry Faculty Publications and Presentations
The effect of perturbing the icosohedral symmetry of C60 by the addition of the side groups -O and -CH2 upon orientational order-disorder and glass transitions in solid C60 has been studied by a combination of high-resolution capacitance dilatometry and single-crystal x-ray and powder inelastic neutron scattering. Both fullerene derivatives C60O (epoxide) and C61H2 (6,5-annulene) are shown to undergo a sequence of transitions similar to that found in pure C60, i.e., a first-order orientational ordering transition just below room temperature followed by an orientational glass transition at lower temperatures. Although the …
Beach Response To Subsidence Following A Cascadia Subduction Zone Earthquake Along The Washington-Oregon Coast, Debra Lee Doyle
Beach Response To Subsidence Following A Cascadia Subduction Zone Earthquake Along The Washington-Oregon Coast, Debra Lee Doyle
Dissertations and Theses
Beach shoreline retreat induced by coseismic subsidence in the Cascadia subduction zone is an important post-earthquake hazard. Sand on a beach acts as a buffer to wave attack, protecting dunes, bluffs and terraces. The loss of sand from a beach could promote critical erosion of the shoreline. This study was initiated in order to estimate the potential amount of post subsidence shoreline retreat on a regional scale in the Central Cascadia Margin. The study area is a 331 km stretch of coastline from Copalis, Washington to Florence, Oregon. Several erosion models were evaluated, and the Bruun model was selected as …
Needed Narrowing As The Computational Strategy Of Evaluable Functions In An Extension Of Goedel, Bobbi J. Barry
Needed Narrowing As The Computational Strategy Of Evaluable Functions In An Extension Of Goedel, Bobbi J. Barry
Dissertations and Theses
A programming language that combines the best aspects of both the functional and logic paradigms with a complete evaluation strategy has been a goal of a Portland State University project team for the last several years. I present the third in a series of modifications to the compiler of the logic programming language Goedel which reaches this goal. This enhancement of Goedel's compiler translates user-defined functions in the form of rewrite rules into code that performs evaluation of these functions by the strategy of needed narrowing. In addition, Goedel's mechanism that evaluates predicates is supplemented so that needed narrowing is …
Multicomponent Diffusion In Two-Temperature Magnetohydrodynamics, John D. Ramshaw, C. H. Chang
Multicomponent Diffusion In Two-Temperature Magnetohydrodynamics, John D. Ramshaw, C. H. Chang
Physics Faculty Publications and Presentations
A recent hydrodynamic theory of multicomponent diffusion in multitemperature gas mixtures [J. D. Ramshaw, J. Non-Equilib. Thermodyn. 18, 121 (1993)] is generalized to include the velocity-dependent Lorentz force on charged species in a magnetic field B. This generalization is used to extend a previous treatment of ambipolar diffusion in two-temperature multicomponent plasmas [J. D. Ramshaw and C. H. Chang, Plasma Chem. Plasma Process. 13, 489 (1993)] to situations in which B and the electrical current density are nonzero. General expressions are thereby derived for the species diffusion fluxes, including thermal diffusion, in both single- and two-temperature multicomponent magnetohydrodynamics (MHD). It …
Wear Due To The Physical And Petrographic Properties Of Rocks And Their Dynamic Interactions With Mining Equipment, Christian Poppeliers
Wear Due To The Physical And Petrographic Properties Of Rocks And Their Dynamic Interactions With Mining Equipment, Christian Poppeliers
Dissertations and Theses
Wear to mining equipment reduces operational efficiency. If wear rates can be predicted, appropriate matching of alloys to the mine' s geologic conditions can aid in improving the operational efficiency. This study addresses rock characteristics which lead to wear. Macroscopic rock tools which lead to wear include sharp edges and comers on rocks. During a rock/equipment interaction, these rock tools cause high point pressures on the surface of the equipment which leads to ductile cutting and gouging of the surface and subsequent removal of metal. Hard mineral grains, or grain tools, produce abrasion as the grains move across equipment surfaces. …
Abstract Index Interfaces, Muralidharan Janakiraman
Abstract Index Interfaces, Muralidharan Janakiraman
Dissertations and Theses
An index in a database system interacts with many of the software modules in the system. For systems supporting a wide range of index structures, interfacing the index code with the rest of the system poses a great problem. The problems are an order of magnitude more for adding new access methods to the system. These problems could be reduced manifold if common interfaces could be specified for different access methods. It would be even better, if these interfaces could be made database-system independent. This thesis addresses the problem of defining generic index interfaces for access methods in database systems. …
Contention-Free Scheduling Of Communication Induced By Array Operations On 2d Meshes, Andreas Bernhard Georg Eberhart
Contention-Free Scheduling Of Communication Induced By Array Operations On 2d Meshes, Andreas Bernhard Georg Eberhart
Dissertations and Theses
Whole array operations and array section operations are important features of many data-parallel languages. Efficient implementation of these operations on distributed-memory multicomputers is critical to the scalability and high-performance of data-parallel programs. This thesis presents an approach for analyzing communication patterns induced by array operations and for using run-time information to schedule the message flow. The distributed, dynamic scheduling algorithms guarantee link-contention-free data transfer and utilize network resources almost optimally. They incur little overhead, which is important in order not to reduce the speedup gained by the parallel execution. The algorithms can be used by compilers for the generation of …
Fluorinated Polymer Films: Synthesis And Characterization, Anja Ulrike Schnurer
Fluorinated Polymer Films: Synthesis And Characterization, Anja Ulrike Schnurer
Dissertations and Theses
Three polyfluoroalkyl epoxides, (I OCH2CHCH2OCF2CF2SO2F, II OCH2CHCH2(CF2)8F and III OCH2CHCH2O(CF2)CF(CF3)SO2F) were photopolymerized with a cycloaliphatic diepoxide (Cyracure UVR-6110) to form highly crosslinked glassy films. Depth-dependent surface analysis with XPS show that these films are highly enriched with sulfonyl fluoride groups in the outer molecular surface. Film compositions of 17 % wt and more of the fluorinated I and III show surface characteristics of a film composed of 100 % wt of the …
Distribution Of Ionized And Neutral Halogenated Phenols In An Octanol-Water Membrane Model System, Robert Word
Distribution Of Ionized And Neutral Halogenated Phenols In An Octanol-Water Membrane Model System, Robert Word
Dissertations and Theses
The accumulation of xenobiotics, such as halogenated phenols, in soils, sediments, and living organisms is primarily a partitioning process between an aquatic and organic phase. It is traditional to use a bulk octanol-water system to model the partitioning of a compound between complex biological lipid membranes and aqueous media. The octanol-water partition coefficient KOW successfully approximates the lipid membrane-water partition coefficient KLipW of neutral compounds. However, the ionized species of substituted phenols were shown to have a higher affinity for lipid membranes than predicted from octanol-water results.
Data on the octanol-water partition coefficients of molecular ions is limited. …
Surface-Enhanced Raman Scattering At Elevated Temperatures, P.T. Leung, M. H. Hider, Erik J. Sánchez
Surface-Enhanced Raman Scattering At Elevated Temperatures, P.T. Leung, M. H. Hider, Erik J. Sánchez
Physics Faculty Publications and Presentations
The effect on surface-enhanced Raman scattering due to the increase in temperature of the metallic substrate is studied via a simple model for physisorbed molecules. Surface roughness is represented by a spherical or spheroidal island, and the temperature effects on the surface plasmon are accounted for via a slightly modified Ujihara model. It is found that the enhancement ratio in general decreases as substrate temperature increases. For noble metals like silver, this temperature effect is particularly pronounced at scattering frequencies close to that of the surface-plasmon resonance; and for frequencies well below the surface plasmon frequency, the enhancement ratio is …
Nmr Study Of Neurophysin Dimer Dissociation By Cosolvents, Jian Yao
Nmr Study Of Neurophysin Dimer Dissociation By Cosolvents, Jian Yao
Dissertations and Theses
Neurophysins (NPs) make up a relatively small, stable, and highly soluble class of proteins. They have physiological roles of storage and stabilizing' of peptide hormones oxytocin and vasopression within the posterior pituitary neurosecretory granules. At the concentration of NP found within the granules, NP would exist as a dimer in the absence or presence of bound peptide. The NP monomer-monomer interface involves B-sheet/ B-sheet contact, which can be modulated by the presence of cosolvent. This remarkable feature of NP makes it a model for Alzheimer's disease. One of the characteristics of Alzheimer's disease is the presence of plaques of B-amyloid …
The Use Of Hydrochemistry To Identify Potential Processes Operating In The Saddle Mountains Basalt Aquifer And The Use Of The Nitrate-Nitrogen Isotope To Distinguish Between Potential Sources Of Nitrate To The Shallow Alluvial Aquifer In The Lower Umatilla Basin, Oregon, Margot Truini
Dissertations and Theses
Nitrate concentration in excess of national drinking-water standards (10 mg/l) are present in the shallow alluvial aquifer and Saddle Mountains Basalt (SMB) aquifer in the Lower Umatilla Basin, Oregon. To determine sources responsible for elevated nitrate concentrations in the SMB aquifer mass-balance and reaction-path models (NETPATH and PHREEQE) were used to understand observed geochemical trends. Nitrate-nitrogen isotopes were used to distinguish potential nitrate sources in the shallow alluvial aquifer. NETPATH-validated simple water/rock reactions in the SMB aquifers in Irrigon (dissolving glass, precipitating smectite, dissolving or precipitating calcite, and cation exchange) using constituents (calcium, magnesium, sodium and carbon). Diversity of composition …
Heme Proton Resonance Assignments And Kinetics Study In High-Spin And Mixed-Spin Metmyoglobin Complexes By Chemical Exchange Nmr Spectroscopy, Ying Luo
Dissertations and Theses
NMR studies of paramagnetic hemoproteins have improved significantly our understanding of the structure-function relationship of hemoproteins in general. Up to date most of the studies focus on low-spin ferric systems which are characterized by relatively narrow resonance peaks and concomitant better resolution.
However, characterizing in detail the NMR spectra of high-spin ferric hemoproteins is important since there are several hemoproteins, such as peroxidases, catalases, oxygenases, and some ferricytochromes that contain high-spin iron (III) in their biologically active forms. Yet assigning resonances from heme peripheral protons and/or heme pocket residues in high-spin myoglobins is a daunting undertaking. Only a sparse number …
Compiling Evaluable Functions In The GöDel Programming Language, David Shapiro
Compiling Evaluable Functions In The GöDel Programming Language, David Shapiro
Dissertations and Theses
We present an extension of the Gödel logic programming language code generator which compiles user-defined functions. These functions may be used as arguments in predicate or goal clauses. They are defined in extended Gödel as rewrite rules. A translation scheme is introduced to convert function definitions into predicate clauses for compilation. This translation scheme and the compilation of functional arguments both employ leftmost-innermost narrowing. As function declarations are indistinguishable from constructor declarations, a function detection method is implemented.
The ultimate goal of this research is the implementation of extended Gödel using needed narrowing. The work presented here is …
The Genetic Algorithm And Maximum Entropy Dice, Laura Suzanne Fellman
The Genetic Algorithm And Maximum Entropy Dice, Laura Suzanne Fellman
Dissertations and Theses
The Brandeis dice problem, originally introduced in 1962 by Jaynes as an illustration of the principle of maximum entropy, was solved using the genetic algorithm, and the resulting solution was compared with that obtained analytically. The effect of varying the genetic algorithm parameters was observed, and the optimum values for population size, mutation rate, and mutation interval were determined for this problem. The optimum genetic algorithm program was then compared to a completely random method of search and optimization. Finally, the genetic algorithm approach was extended to several variations of the original problem for which an analytical approach would be …
The Shape Of Self-Motion Perception. Ii. Framework And Principles For Simple And Complex Motions, Jan E. Holly, Gin Mccollum
The Shape Of Self-Motion Perception. Ii. Framework And Principles For Simple And Complex Motions, Jan E. Holly, Gin Mccollum
Gin McCollum
There have been numerous experimental studies on human perception and misperception of self-motion and orientation relative to the earth, each focusing on one or a few types of motion. We present a formal framework encompassing many types of motion and including all angular and linear components of velocity and acceleration. Using a mathematically rigorous presentation, the framework defines the space of all possible motions, the map from motion to sensor status, the space containing each possible status of the sensors, and the map from sensor status to perceived motion. The shape of the full perceptual map from actual motion to …
The Stomatogastric Nervous System: A Formal Approach, Patrick D. Roberts, Gin Mccollum
The Stomatogastric Nervous System: A Formal Approach, Patrick D. Roberts, Gin Mccollum
Gin McCollum
A discrete mathematical formalism (d-space) which is specifically designed to investigate discrete aspects of behavior is applied to the foregut of decapod crustacea. This approach differs from continuous modeling techniques in that the analysis determines a structure in which the observed behavior of the foregut is constrained. A notation for the implementation of the formalism is developed as well as a coordinate system natural to the functioning of the gastric mill. The formalism is used to organize previous observations that suggest potential courses of further experimental investigation. A detailed analysis of observed chewing modes of the gastric mill is presented, …
An Ice-Shelf Model Test Based On The Ross Ice Shelf, D. R. Macayeal, V. Rommelaere, P. Huybrechts, Christina L. Hulbe, J. Determann, C. Ritz
An Ice-Shelf Model Test Based On The Ross Ice Shelf, D. R. Macayeal, V. Rommelaere, P. Huybrechts, Christina L. Hulbe, J. Determann, C. Ritz
Geology Faculty Publications and Presentations
A standard numerical experiment featuring the Ross Ice Shelf, Antarctica, is presented as a test package for the development and intercomparison of ice-shelf models. The emphasis of this package is solution of stress-equilibrium equations for an ice-shelf velocity consistent with present observations. As a demonstration, we compare five independently developed ice-shelf models based on finite-difference and finite-element methods. Our results suggest that there is little difference between finite-element and finite-difference methods in capturing the basic, large-scale flow features of the ice shelf. We additionally show that the fit between model and observed velocity depends strongly on the ice-shelf temperature field …
Simple Approximation For Thermal Diffusion In Ionized Gas Mixtures, John D. Ramshaw
Simple Approximation For Thermal Diffusion In Ionized Gas Mixtures, John D. Ramshaw
Physics Faculty Publications and Presentations
A simple approximation for thermal diffusion in gas mixtures was recently proposed [1]. This approximation was based upon relations valid for rigid spheres. It is therefore appropriate for molecules with steep repulsive potentials, but not for ionized species interacting via the Coulomb potential. Here we formulate an analogous approximation for ionized species and free electrons. The resulting thermal diffusion coefficients differ in sign from those for hard molecules.