Physical Sciences and Mathematics Commons^™

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 …

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 …

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 …

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) …

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, …

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.

Infofilter: Supporting Quality Of Service For Fresh Information Delivery, Ling Liu, Calton Pu, Karsten Schwan, Jonathan Walpole

Computer Science Faculty Publications and Presentations

With the explosive growth of the Internet and World Wide Web comes a dramatic increase in the number of users that compete for the shared resources of distributed system environments. Most implementations of application servers and distributed search software do not distinguish among requests to different web pages. This has the implication that the behavior of application servers is quite unpredictable. Applications that require timely delivery of fresh information consequently suffer the most in such competitive environments. This paper presents a model of quality of service (QoS) and the design of a QoS-enabled information delivery system that implements such a …

Managing Our Environmental Portfolio, Robert Costanza, Herman E. Daly, Carl Folke, Paul Hawken, C. S. Holling, A. J. Mcmichael, David Pimentel, David Rapport

Institute for Sustainable Solutions Publications and Presentations

No set of issues has tended to separate economists and ecologists, especially in the mind of the public, more than those surrounding the linkages between economic growth, human carrying capacity, and the environment. The general lack of interest among the majority of economists in problems of the environment and a parallel lack of interest among the majority of ecologists in economic issues, combined with a lack of dialogue between the two groups, has allowed extreme positions to take hold in the public debate and to influence policy to an inordinate degree.

Effect Of Slow Compression On The Linear Stability Of An Accelerated Shear Layer, John D. Ramshaw

Physics Faculty Publications and Presentations

An analysis is given of the effect of a slow uniform anisotropic compression or expansion on the linear stability of a normally accelerated planar interface between two fluids with different densities and tangential velocities, i.e., a combined Kelvin-Helmholtz and Rayleigh-Taylor instability, but generalized to an arbitrary time-dependent acceleration history. The compression is presumed to be sufficiently slow that the density remains uniform within each fluid and hence depends only on time. The perturbation is taken to be sinusoidal with amplitude h(t). The time evolution of h is determined by requiring pressure continuity across the interface in the usual way. The …

Survey Of Aquatic Plants In Corps Of Engineers Reservoirs, Kimberly D. Walker, Mark D. Sytsma

Center for Lakes and Reservoirs Publications and Presentations

A survey of aquatic plants in a selected Corps of Engineers reservoirs in Oregon was conducted. Cottage Grove, Dorena, Fern Ridge, Dexter and Willow Creek Reservoirs contained abundant aquatic plants. Potamogeton pectinatus and Potamogeton epihydrous were the most common native plant species. Myriophyllum aquaticum and Potamogeton crispus were the most widespread nonnative plants. Species richness in the reservoirs was correlated with trophic status and basin morphology. Shallow reservoirs that included extensive areas of nutrient-rich sediments that were historic flood plain soils supported the greatest biomass and number of species. Mesotrophic reservoirs had lower species diversity. Oligotrophic reservoirs with steep basin …

Variation Of Constitutive Model Formulation On Analytical Cake Filtration Models, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

Constitutive properties are required to model porosity, effective stress, porewater pressure, or permeability during cake filtration. By using an analytical cake filtration model based on Tiller (1975) with various constitutive property formulations, predictions of effective stress, permeability, and porosity distributions in a filter cake can be made. This analytical approach was only valid when spatially average values of porosity and pressure differential were constant over time. Several different constitutive property formulations were compared to data of effective stress and permeability as a function of porosity for kaolin clay in water. Also the spatial distribution of porosity in a filter cake …

Estimation Of A Monotone Mean Residual Life, Subhash C. Kochar, Hari Mukerjee, Francisco J. Samaniego

Mathematics and Statistics Faculty Publications and Presentations

In survival analysis and in the analysis of life tables an important biometric function of interest is the life expectancy at age x,M(x), defined by M(x)=E[X?x|X>x], where X is a lifetime. M is called the mean residual life function. In many applications it is reasonable to assume that M is decreasing (DMRL) or increasing (IMRL); we write decreasing (increasing) for nonincreasing (non-decreasing). There is some literature on empirical estimators of M and their properties. Although tests for a monotone M are discussed in the literature, we are not aware of any estimators of M under these order restrictions. In …

Multigrid For The Mortar Finite Element Method, Jay Gopalakrishnan, Joseph E. Pasciak

Mathematics and Statistics Faculty Publications and Presentations

A multigrid technique for uniformly preconditioning linear systems arising from a mortar finite element discretization of second order elliptic boundary value problems is described and analyzed. These problems are posed on domains partitioned into subdomains, each of which is independently triangulated in a multilevel fashion. The multilevel mortar finite element spaces based on such triangulations (which need not align across subdomain interfaces) are in general not nested. Suitable grid transfer operators and smoothers are developed which lead to a variable Vcycle preconditioner resulting in a uniformly preconditioned algebraic system. Computational results illustrating the theory are also presented.

Greenhouse Gases And Other Airborne Pollutants From Household Stoves In China: A Database For Emission Factors, J. Zhang, K. R. Smith, Y. Ma, S. Ye, F. Jiang, W. Qi, P. Liu, M. A. K. Khalil, R. A. Rasmussen, S. A. Thorneloe

Physics Faculty Publications and Presentations

Emissions from household stoves, especially those using solid fuels, can contribute significantly to greenhouse gas (GHG) inventories and have adverse health impacts. Few data are available on emissions from the numerous types of cookstoves used in developing countries. We have systematically measured emissions from 56 fuel/stove combinations in India and China, a large fraction of the combinations in use world-wide. A database was generated containing emission factors of direct and indirect GHGs and other airborne pollutants such as CO2, CO, CH4, TNMHC, N2O, SO2, NOx, TSP, etc. In this paper, we report on the 28 fuel/stove combinations tested …

Molecular Interaction Between Nitric Oxide And Ryanodine Receptors Of Skeletal And Cardiac Sarcoplasmic Reticulum, Guy Salama, Elizaveta V. Menshikova, Jonathan J. Abramson

Physics Faculty Publications and Presentations

In striated muscle, the sarcoplasmic reticulum (SR) is the major storage compartment of intracellular Ca2+ that controls cytosolic free Ca2+ (Cai) and developed force by sequestering and releasing Ca2+ during each contraction. Ca2+ release from the SR occurs through high-conductance Ca2+ release channels or ryanodine receptors (RyR), which are regulated by various signaling processes. Over the last 15 years, there has been a growing consensus that critical sulfhydryl sites on RyRs can be oxidized and reduced, respectively, to open and close the release channels. The pharmacological actions of various classes of sulfhydryl reagents have demonstrated the existence of hyperreactive thiols …

Conservation Des Habitats De Roussettes De Livingstone – Les Massifs Forestiers D’Anjouan Et Moheli, Comores: Utilisation D’Indicateurs Sociaux Et Ecologiques, Elise F. Granek

Environmental Science and Management Faculty Publications and Presentations

Le déboisement sur les lles d'Anjouan et Moheli a augmenté a un taux alarmant au cours de ce siecle (PNUD 1998). Ce changement de la couverture des sols et des forets naturelles a des consequences nefastes pour toutes les especes vivant sur les iles, en particulier pour les especes vegetales et animales endemiques, et les communautes humaines locales. Pour diminuer la pression anthropique sur Ie milieu naturel, le Fonds pour l'Environnement Mondial et Ie PNUD ont mis en place un projet de cinq ans qui travaille avec Ie Ministere comorien de l'Environnement pour creer un reseau d'aires protegees dans les …

An Analysis Of Pteropus Livingstonii Roost Habitat: Indicators For Forest Conservation On Anjouan And Moheli, Elise F. Granek

Environmental Science and Management Faculty Publications and Presentations

Livingstone's fruit bat (Pteropus livingstonii) is an endangered and endemic species found only on the islands of Anjouan and Mohéli, Comoros. A study was conducted into the habitats selected by P. livingstonii, as part of a project to assess areas for nature reserves which will be able to protect and conserve forest resources in the islands; the bat is postulated to be a useful indicator of undisturbed forest. Known roost sites (n=9) before the survey were between 500 and 1100 m altitude, on steeply sloping land, with some indigenous forest cover present. Thirteen new potential roost sites were identified, of …

Mortar Estimates Independent Of Number Of Subdomains, Jay Gopalakrishnan

Mathematics and Statistics Faculty Publications and Presentations

The stability and error estimates for the mortar finite element method are well established. This work examines the dependence of constants in these estimates on shape and number of subdomains. By means of a Poincar´e inequality and some scaling arguments, these estimates are found not to deteriorate with increase in number of subdomains.

About Non-Spherically Symmetric Deformations Of An Incompressible Neo-Hookean Sphere, Marek Elźanowski

Mathematics and Statistics Faculty Publications and Presentations

A class of non-spherically symmetric deformations of a neo-Hookean incompressible elastic ball is considered. It is shown that the only possible solution, the cavitated radially symmetric solution and the deformation of radial inflation and polar stretching. These are the same solutions as found by Polignone-Warne and Warne [6] for a smaller class of deformations. This fact shows once again that the radial deformations are the only deformations, at least within the class considered, which may support a formation of a cavity in the center of an incompressible, isotropic, elastic sphere.

Variability In Winter Mass Balance Of Northern Hemisphere Glaciers And Relations With Atmospheric Circulation, Gregory J. Mccabe, Andrew G. Fountain, Mark Dyurgerov

Geography Faculty Publications and Presentations

An analysis of variability in the winter mass balance (WMB) of 22 glaciers in the Northern Hemisphere indicates two primary modes of variability that explain 46% of the variability among all glaciers. The first mode of variability characterizes WMB variability in Northern and Central Europe and the second mode primarily represents WMB variability in northwestern North America, but also is related to variability in WMB of one glacier in Europe and one in Central Asia. These two modes of WMB variability are explained by variations in mesoscale atmospheric circulation which are driving forces of variations in surface temperature and precipitation. …

State-Based Reconstructability Modeling For Decision Analysis, Michael S. Johnson, Martin Zwick

Systems Science Faculty Publications and Presentations

Reconstructability analysis (RA) is a method for detecting and analyzing the structure of multivariate categorical data. Jones and his colleagues extended the original variable-based formulation of RA to encompass models defined in terms of system states (Jones 1982; Jones 1985; Jones 1985; Jones 1986; Jones 1989). In this paper, we demonstrate that Jones’ previous work comprises two separable ideas: the “g to k” transformation and state-based modeling. We relate the concept of state-based modeling to established variable-based RA methods (Klir 1985; Krippendorff 1986), and demonstrate that statebased modeling, when applied to event and decision tree models, is a valuable adjunct …

Life And Evolution In Computers, Melanie Mitchell

Computer Science Faculty Publications and Presentations

This paper argues for the possibility of 'artificial life' and computational evolution, first by discussing (via a highly simplified version) John von Neumann's self-reproducing automaton and then by presenting some recent work focusing on computational evolution, in which 'cellular automata', a form of parallel and decentralized computing system, are evolved via 'genetic algorithms'. It is argued that such in silico experiments can help to make sense of the question of whether we can eventually build computers that are intelligent and alive.

The Link Between Climate Warming And Break-Up Of Ice Shelves In The Antarctic Peninsula, Ted A. Scambos, Christina L. Hulbe, Mark A. Fahnestock, Jennifer Bohlander

Geology Faculty Publications and Presentations

A review of in situ and remote-sensing data covering the ice shelves of the Antarctic Peninsula provides a series of characteristics closely associated with rapid shelf retreat: deeply embayed ice fronts; calving of myriad small elongate bergs in punctuated events; increasing flow speed; and the presence of melt ponds on the ice-shelf surface in the vicinity of the break-ups. As climate has warmed in the Antarctic Peninsula region, melt-season duration and the extent of ponding have increased. Most break-up events have occurred during longer melt seasons, suggesting that meltwater itself, not just warming, is responsible. Regions that show melting without …

Tributaries To West Antarctic Ice Streams: Characteristics Deduced From Numerical Modelling Of Ice Flow, Christina L. Hulbe, Ian R. Joughin, David L. Morse, R. A. Bindschadler

Geology Faculty Publications and Presentations

A network of relatively fast-flowing tributaries in the catchment basins of the West Antarctic ice streams transport ice from the inland reservoir to the heads of the ice streams. Branches of the network follow valleys in basal topography, but not all valleys contain tributaries. We investigate the circumstances favoring tributary flow upstream of Ice Streams D and E, using a combination of observation and numerical modelling. No consistent pattern emerges. The transition from tributary to ice-stream flow occurs smoothly along the main tributary feeding into the onset of Ice Stream D, with ice thickness being relatively more important upstream, and …

A Determination Of Parentage, Mating System, And Genetic Diversity In A Captive Population Of The Straw-Colored Fruit Bat (Eidolon Helvum), Jan Zinck

Dissertations and Theses

Small populations tend to lose genetic variability. The magnitude of this loss is influenced by the number of founding individuals, the genetic diversity of the founders, and the species mating system. Genetic variability is the basis of adaptive evolution, and the loss of genetic variability may have harmful effects on development, growth, and survival. Therefore, a primary management goal for small, captive populations is the retention of genetic variability. Of considerable importance to conservation biology is the determination of parentage, from which mating, genetic, and demographic information can be derived. Microsatellites provide a robust molecular evolutionary tool for the study …

The Long-Term Viability Of A Zero-Valent Iron Permeable Reactive Barrier, Stuart Cowburn

Dissertations and Theses

Zero-valent iron permeable reactive barriers (PRB's) hold significant potential as a tool for groundwater remediation. Uncertainties remain, however, as to the effective lifetime of Fe⁰ barrier technology under full-scale operational conditions. Potential limits on barrier lifetime include reductions in permeability due to clogging by precipitates and oxidation of all Fe⁰ prior to the exhaustion of the contaminant source.

A 46 m long, 0.6 m wide, and 7.3 m deep Fe⁰ PRB was installed at the US Coast Guard Support Center, Elizabeth City, NC, in June 1996. The barrier was designed to remediate groundwater principally contaminated with Cr(VI) …

Ce-Qual-W2 Version 3: Hydrodynamic And Water Quality River Basin Modeling, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

CE-QUAL-W2 is a two-dimensional (longitudinal-vertical) water quality and hydrodynamic computer simulation model that was originally developed for deep, long, and narrow waterbodies. The current model, Version 2, has been used in over 200 river, reservoir/lake, and estuary applications throughout the U.S. and abroad. Version 2, though, cannot accommodate systems that have a significant sloping water surface since the vertical coordinate system is aligned with gravity and vertical accelerations are neglected. The governing equations for CE-QUAL-W2 were re-derived so that it could be applied to entire river basins including river-estuary, lake-river, and reservoir-river systems with channel slopes. This re-derivation is one …