Physical Sciences and Mathematics Commons^™

Subgradients Of Minimal Time Functions Without Calmness, Nguyen Mau Nam, Dang Van Cuong

Mathematics and Statistics Faculty Publications and Presentations

In recent years there has been great interest in variational analysis of a class of nonsmooth functions called the minimal time function. In this paper we continue this line of research by providing new results on generalized differentiation of this class of functions, relaxing assumptions imposed on the functions and sets involved for the results. In particular, we focus on the singular subdifferential and the limiting subdifferential of this class of functions.

Sensitivity Of Conus Summer Rainfall To The Selection Of Cumulus Parameterization Schemes In Nu-Wrf Seasonal Simulations, Takamichi Iguchi, Wei-Kuo Tao, Di Wu, Christa D. Peters-Lidard, Joseph A. Santanello, Eric Kemp, Yudong Tian, Jonathan Case, Weile Wang, Robert Ferraro, Duane E. Waliser, Jinwon Kim, Huikyo Lee, Bin Guan, Baijun Tian, Paul C. Loikith

Geography Faculty Publications and Presentations

This study investigates the sensitivity of daily rainfall rates in regional seasonal simulations over the contiguous United States (CONUS) to different cumulus parameterization schemes. Daily rainfall fields were simulated at 24-km resolution using the NASA-Unified Weather Research and Forecasting (NU-WRF) Model for June–August 2000. Four cumulus parameterization schemes and two options for shallow cumulus components in a specific scheme were tested. The spread in the domain-mean rainfall rates across the parameterization schemes was generally consistent between the entire CONUS and most subregions. The selection of the shallow cumulus component in a specific scheme had more impact than that of the …

Forecasted Range Shifts Of Arid-Land Fishes In Response To Climate Change, James E. Whitney, Joanna B. Whittier, Craig Patrick Paukert, Julian D. Olden, Angela L. Strecker

Environmental Science and Management Faculty Publications and Presentations

Climate change is poised to alter the distributional limits, center, and size of many species. Traits may influence different aspects of range shifts, with trophic generality facilitating shifts at the leading edge, and greater thermal tolerance limiting contractions at the trailing edge. The generality of relationships between traits and range shifts remains ambiguous however, especially for imperiled fishes residing in xeric riverscapes. Our objectives were to quantify contemporary fish distributions in the Lower Colorado River Basin, forecast climate change by 2085 using two general circulation models, and quantify shifts in the limits, center, and size of fish elevational ranges according …

Leed O+M Materials Audit: Blumel Hall, Emily Murkland, Taylor Stone, John Dea, Kristen Purdy

Campus Sustainability Office Publications, Reports and Presentations

• This report provides the Campus Sustainability Office with an objective, third party Materials Audit for Blumel Hall in Portland, Oregon. The data collected for this audit provides Campus Sustainability Office with insight into Blumel’s current waste composition and diversion rate as well as identifies opportunities to improve recycling, composting, and areas for reduction of materials consumption. Community Environmental Services (CES) conducted Materials Audits for 100% of Blumel Hall’s landfill-bound, commingled recycling, glass bottles and jars recycling, and compost streams during a 24-hour period.

Psu Urban Center Building Leed Eb Materials Audit Report, Emily Murkland, Taylor Stone, John Dea, Kristen Purdy

Campus Sustainability Office Publications, Reports and Presentations

This report provides the Campus Sustainability Office with an objective, third party Materials Audit for Portland State University’s Urban Center Building in Portland, Oregon. The data collected for this audit provides Campus Sustainability Office with insight into Urban Center’s current waste composition and diversion rate as well as identifies opportunities to improve recycling, composting, and areas for reduction of materials consumption. Community Environmental Services (CES) conducted materials audits for 100% of Urban Center’s landfill-bound, commingled recycling, glass bottles and jars recycling, and compost streams during a 24-hour period.

The Effect Of Plasma On Graphene Quality In An Inductively Couple Plasma Chemical Vapor Deposition Reactor, Brendan Coyne

Undergraduate Research & Mentoring Program

Despite continued interest in research and application development, full scale graphene production is still limited by many factors including prohibitively high growth temperature requirements. Extremely high quality graphene growth is possible at high temperatures using chemical vapor deposition (CVD). Use of an inductively coupled plasma chemical vapor deposition (ICP CVD) reactor with the benefit of precursor gas decomposition through plasma generation, may provide possibility to reduce growth temperature. Herein, we report plasma’s effects on graphene growth by comparing growths of increasing power supplied to plasma generation and changes in precursor gas ratios. Plasma composition was characterized by ultraviolet and visible …

Gas Transfer Velocities In Small Forested Ponds, Meredith A. Holgerson, Emily R. Farr, Peter A. Raymond

Environmental Science and Management Faculty Publications and Presentations

Inland waters actively exchange gases with the atmosphere, and the gas exchange rate informs system biogeochemistry, ecology, and global carbon budgets. Gas exchange in medium- to large-sized lakes is largely regulated by wind; yet less is known about processes regulating gas transfer in small ponds where wind speeds are low. In this study, we determined the gas transfer velocity, k₆₀₀, in four small ( < 250 m² ) ponds by using a propane ( C₃H₈ ) gas injection. When estimated across 12 h periods, the average k₆₀₀ ranged from 0.19 to 0.72 m d^-1 across …

Continental-Scale Homogenization Of Residential Lawn Plant Communities, Megan M. Wheeler, Christopher Neill, Peter M. Groffman, Meghan Avolio, Neil D. Bettez, Jeannine Cavender-Bares, Rinku Roy Chowdhury, Lindsay Darling, J. Morgan Grove, Sharon J. Hall, James B. Heffernan, Sarah E. Hobbie, Kelli L. Larson, Jennifer L. Morse, Kristen C. Nelson, Laura A. Ogden, Jarlath O'Neil-Dunne, Diane E. Pataki, Colin Polsky, Meredith Steele, Tara Trammell

Environmental Science and Management Faculty Publications and Presentations

Residential lawns are highly managed ecosystems that occur in urbanized landscapes across the United States. Because they are ubiquitous, lawns are good systems in which to study the potential homogenizing effects of urban land use and management together with the continental-scale effects of climate on ecosystem structure and functioning. We hypothesized that similar homeowner preferences and management in residential areas across the United States would lead to low plant species diversity in lawns and relatively homogeneous vegetation across broad geographical regions. We also hypothesized that lawn plant species richness would increase with regional temperature and precipitation due to the presence …

Competition Amplifies Drought Stress In Forests Across Broad Climatic And Compositional Gradients, Kelly E. Gleason, John B. Bradford, Alessandra Bottero, Anthony W. D'Amato, Shawn Fraver, Brian J. Palik, Michael A. Battaglia, Louis Iverson, Laura Kenefic, Christel C. Kern

Environmental Science and Management Faculty Publications and Presentations

Forests around the world are experiencing increasingly severe droughts and elevated competitive intensity due to increased tree density. However, the influence of interactions between drought and competition on forest growth remains poorly understood. Using a unique dataset of stand-scale dendrochronology sampled from 6405 trees, we quantified how annual growth of entire tree populations responds to drought and competition in eight, long-term (multi-decadal), experiments with replicated levels of density (e.g., competitive intensity) arrayed across a broad climatic and compositional gradient. Forest growth (cumulative individual tree growth within a stand) declined during drought, especially during more severe drought in drier climates. Forest …

Environmental Dna (Edna) Detects The Invasive Crayfishes Orconectes Rusticus And Pacifastacus Leniusculus In Large Lakes Of North America, Eric R. Larson, Mark A. Renshaw, Crysta Gantz, John Umek, Sudeep Chandra, David M. Lodge, Scott P. Egan

Environmental Science and Management Faculty Publications and Presentations

We report results of a study that made reciprocal comparisons of environmental DNA (eDNA) assays for two major invasive crayfishes between their disparate invasive ranges in North America. Specifically, we tested for range expansions of the signal crayfish Pacifastacus leniusculus (Dana, 1852) into the Laurentian Great Lakes region known to be invaded by the rusty crayfish Orconectes rusticus (Girard, 1852), as well as for the invasion of O. rusticus into large lakes of California and Nevada, US known to be invaded by P. leniusculus. We compared eDNA detections to historic localities for O. rusticus within the Great Lakes, and to …

Essentials Of Building Virtual Instruments With Labview And Arduino For Lab Automation Applications, Jianghua Bai, Andres H. La Rosa

Physics Faculty Publications and Presentations

Four ways to improve the capabilities of a virtual instrument involving a microcontroller are covered in this paper. They are structural modeling and programming, real-time control, asynchronous communication between the microcontroller and the host PC, and system integration. This paper covers 4 common problems encountered by embedded developers and 5 solutions to the 4 problems. The solutions and examples demonstrated in this article will help readers build robust and reliable virtual instruments for crucial applications.

Evidence For Distributed Clockwise Rotation Of The Crust In The Northwestern United States From Fault Geometries And Focal Mechanisms, Thomas M. Brocher, Ray E. Wells, Andrew P. Lamb, Craig S. Weaver

Geology Faculty Publications and Presentations

Paleomagnetic and GPS data indicate that Washington and Oregon have rotated clockwise for the past 16 Myr. Late Cenozoic and Quaternary fault geometries, seismicity lineaments, and focal mechanisms provide evidence that this rotation is accommodated by north directed thrusting and right-lateral strike-slip faulting in Washington, and SW to W directed normal faulting and right-lateral strike-slip faulting to the east. Several curvilinear NW to NNW trending high-angle strike-slip faults and seismicity lineaments in Washington and NW Oregon define a geologic pole (117.7°W, 47.9°N) of rotation relative to North America. Many faults and focal mechanisms throughout northwestern U.S. and southwestern British Columbia …

Using An Altimeter-Derived Internal Tide Model To Remove Tides From In Situ Data, Edward D. Zaron, Richard D. Ray

Civil and Environmental Engineering Faculty Publications and Presentations

Internal waves at tidal frequencies, i.e., the internal tides, are a prominent source of variability in the ocean associated with significant vertical isopycnal displacements and currents. Because the isopycnal displacements are caused by ageostrophic dynamics, they contribute uncertainty to geostrophic transport inferred from vertical profiles in the ocean. Here it is demonstrated that a newly developed model of the main semidiurnal (M2) internal tide derived from satellite altimetry may be used to partially remove the tide from vertical profile data, as measured by the reduction of steric height variance inferred from the profiles. It is further demonstrated that the internal …

Simplified Reversed Chloroquines To Overcome Malaria Resistance To Quinoline-Based Drugs, Bornface Gunsaru, Steven J. Burgess, Westin Morrill, Jane X. Kelly, Shawheen Shomloo, Martin J. Smilkstein, Katherine May Liebman, David H. Peyton

Chemistry Faculty Publications and Presentations

Building on our earlier work of attaching a chemosensitizer (reversal agent) to a known drug pharmacophore, we have now expanded the structure-activity relationship study to include simplified versions of the chemosensitizer. The change from two aromatic rings in this head group to a single ring does not appear to detrimentally affect the antimalarial activity of the compounds. Data from in vitro heme binding and beta-hematin inhibition assays suggest that the single aromatic RCQ compounds retain activities against Plasmodium falciparum similar to those of CQ, although other mechanisms of action may be relevant to their activities.

Slope, Grain Size, And Roughness Controls On Dry Sediment Transport And Storage On Steep Hillslopes, Roman A. Dibiase, Michael P. Lamb, Vamsi Ganti, Adam M. Booth

Geology Faculty Publications and Presentations

Existing hillslope sediment transport models developed for low-relief, soil-mantled landscapes are poorly suited to explain the coupling between steep rocky hillslopes and headwater channels. Here we address this knowledge gap using a series of field and numerical experiments to inform a particle-based model of sediment transport by dry ravel—a mechanism of granular transport characteristic of steep hillslopes. We find that particle travel distance increases as a function of the ratio of particle diameter to fine-scale (1m) topographic variability associated with rocky landscapes. Applying a 2-D dry-ravel-routing model to lidar-derived surface topography, we show how spatial patterns of local and nonlocal …

Past, Present, And Future Of Ecological Integrity Assessment For Fresh Waters, Lauren M. Kuehne, Julian D. Olden, Angela L. Strecker, Joshua J. Lawler, David M. Theobald

Environmental Science and Management Faculty Publications and Presentations

One of the most influential environmental laws in the US – the 1972 Clean Water Act – included the visionary objective of maintaining and restoring aquatic ecological integrity. However, the efficacy of the Act depends on how integrity is assessed. Reviewing the assessment literature for fresh waters over the past 40 years, we found evidence of methodological trends toward increased repeatability, transferability, and robustness of assessments over time. However, implementation gaps were revealed, based on the relatively weak linkages to freshwater policies, stakeholder involvement, emerging threats, and conservation opportunities. A related survey of assessment practitioners underscored the disparity between need …

Advancing Collaborative Solutions: Lessons From The Oregon Sage-Grouse Conservation Partnership (Sagecon), Jennifer H. Allen, Turner Odell, Julia Babcock, Charis Henrie

National Policy Consensus Center Publications and Reports

The Sage-Grouse Conservation Partnership, also known as “SageCon,” was an unprecedented collaborative effort among federal, state, and private stakeholders to address landscape-scale threats to greater sage-grouse while also acknowledging rural economic and community interests across eastern Oregon’s sagebrush range. A U.S. Fish and Wildlife Service (USFWS) preliminary finding that the sage-grouse warranted listing under the endangered species act, and a subsequent court settlement setting a deadline for a final listing decision were key drivers for SageCon participants to seek proactive solutions to protect the bird. A cadre of diverse Eastern Oregon stakeholders with experience working collaboratively on related public lands …

Quef-Like, A Non-Homologous Archaeosine Synthase From The Crenarchaeota, Adriana Bon Ramos, Lide Bao, Ben Turner, Valérie De Crécy-Lagard, Dirk Iwata-Reuyl

Chemistry Faculty Publications and Presentations

Archaeosine (G+) is a structurally complex modified nucleoside ubiquitous to the Archaea, where it is found in the D-loop of virtually all archaeal transfer RNA (tRNA). Its unique structure, which includes a formamidine group that carries a formal positive charge, and location in the tRNA, led to the proposal that it serves a key role in stabilizing tRNA structure. Although G+ is limited to the Archaea, it is structurally related to the bacterial modified nucleoside queuosine, and the two share homologous enzymes for the early steps of their biosynthesis. In the Euryarchaeota, the last step of the archaeosine biosynthetic pathway …

Remote Measurements Of Tides And River Slope Using An Airborne Lidar Instrument, Austin S. Hudson, Stefan A. Talke, Ruth Branch, Chris Chickadel, Gordon Farquharson, Andrew Jessup

Civil and Environmental Engineering Faculty Publications and Presentations

Tides and river slope are fundamental characteristics of estuaries, but they are usually undersampled due to deficiencies in the spatial coverage of water level measurements. This study aims to address this issue by investigating the use of airborne lidar measurements to study tidal statistics and river slope in the Columbia River estuary. Eight plane transects over a 12-h period yield at least eight independent measurements of water level at 2.5-km increments over a 65-km stretch of the estuary. These data are fit to a sinusoidal curve and the results are compared to seven in situ gauges. In situ– and lidar-based …

Topological And Thermodynamic Factors That Influence The Evolution Of Small Networks Of Catalytic Rna Species, Jessica Anne Mellor Yeates, Philippe Nghe, Niles Lehman

Chemistry Faculty Publications and Presentations

An RNA-directed recombination reaction can result in a network of interacting RNA species. It is now becoming increasingly apparent that such networks could have been an important feature of the RNA world during the nascent evolution of life on the Earth. However, the means by which such small RNA networks assimilate other available genotypes in the environment to grow and evolve into the more complex networks that are thought to have existed in the prebiotic milieu are not known. Here, we used the ability of fragments of the Azoarcus group I intron ribozyme to covalently self-assemble via genotype-selfish and genotype-cooperative …

Atomic Layer Growth Of Inse And Sb₂Se₃ Layered Semiconductors And Their Heterostructure, Robert Browning, Neal Kuperman, Bill Moon, Raj Solanki

Physics Faculty Publications and Presentations

Metal chalcogenides based on the C–M–M–C (C = chalcogen, M = metal) structure possess several attractive properties that can be utilized in both electrical and optical devices. We have shown that specular, large area films of ^_y-InSe and Sb₂Se₃ can be grown via atomic layer deposition (ALD) at relatively low temperatures. Optical (absorption, Raman), crystalline (X-ray diffraction), and composition (XPS) properties of these films have been measured and compared to those reported for exfoliated films and have been found to be similar. Heterostructures composed of a layer of y-InSe (intrinsically n-type) followed by a layer of …

Shift-Symmetric Configurations In Two-Dimensional Cellular Automata: Irreversibility, Insolvability, And Enumeration, Peter Banda, John S. Caughman Iv, Martin Cenek, Christof Teuscher

Mathematics and Statistics Faculty Publications and Presentations

The search for symmetry as an unusual yet profoundly appealing phenomenon, and the origin of regular, repeating configuration patterns have been for a long time a central focus of complexity science, and physics.

Here, we introduce group-theoretic concepts to identify and enumerate the symmetric inputs, which result in irreversible system behaviors with undesired effects on many computational tasks. The concept of so-called configuration shift-symmetry is applied on two-dimensional cellular automata as an ideal model of computation. The results show the universal insolvability of “non-symmetric” tasks regardless of the transition function. By using a compact enumeration formula and bounding the number …

Spatial Resilience Of Forested Landscapes Under Climate Change And Management, Melissa S. Lucash, Robert M. Scheller, Eric J. Gustafson, Brian R. Sturtevant

Environmental Science and Management Faculty Publications and Presentations

Context: Resilience, the ability to recover from disturbance, has risen to the forefront of scientific policy, but is difficult to quantify, particularly in large, forested landscapes subject to disturbances, management, and climate change.

Objectives: Our objective was to determine which spatial drivers will control landscape resilience over the next century, given a range of plausible climate projections across north-central Minnesota.

Methods: Using a simulation modelling approach, we simulated wind disturbance in a 4.3 million ha forested landscape in north-central Minnesota for 100 years under historic climate and five climate change scenarios, combined with four management scenarios: business …

Analyzing Glacier Surface Motion Using Lidar Data, Jennifer W. Tellig, Craig Glennie, Andrew G. Fountain, David C. Finnegan

Geology Faculty Publications and Presentations

Understanding glacier motion is key to understanding how glaciers are growing, shrinking, and responding to changing environmental conditions. In situ observations are often difficult to collect and offer an analysis of glacier surface motion only at a few discrete points. Using light detection and ranging (LiDAR) data collected from surveys over six glaciers in Greenland and Antarctica, particle image velocimetry (PIV) was applied to temporally-spaced point clouds to detect and measure surface motion. The type and distribution of surface features, surface roughness, and spatial and temporal resolution of the data were all found to be important factors, which limited the …

Benzene Formation In Electronic Cigarettes, James F. Pankow, Kilsun Kim, Kevin J. Mcwhirter, Wentai Luo, Jorge O. Escobedo, Robert M. Strongin, Anna K. Duell, David H. Peyton

Chemistry Faculty Publications and Presentations

The heating of the fluids used in electronic cigarettes (“e-cigarettes”) used to create “vaping” aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen) from e-cigarette fluids containing propylene glycol (PG), glycerol (GL), benzoic acid, the flavor chemical benzaldehyde, and nicotine.

Nesterov's Smoothing Technique And Minimizing Differences Of Convex Functions For Hierarchical Clustering, Mau Nam Nguyen, Wondi Geremew, Sam Raynolds, Tuyen Tran

Mathematics and Statistics Faculty Publications and Presentations

A bilevel hierarchical clustering model is commonly used in designing optimal multicast networks. In this paper we will consider two different formulations of the bilevel hierarchical clustering problem -- a discrete optimization problem which can be shown to be NP-hard. Our approach is to reformulate the problem as a continuous optimization problem by making some relaxations on the discreteness conditions. This approach was considered by other researchers earlier, but their proposed methods depend on the square of the Euclidian norm because of its differentiability. By applying the Nesterov smoothing technique and the DCA -- a numerical algorithm for minimizing differences …

Network Analysis Of Wildfire Transmission And Implications For Risk Governance, Alan A. Ager, Cody Evers, Michelle A. Day, Haiganoush K. Preisler, Ana M.G. Barros, Max Nielsen-Pincus

Environmental Science and Management Faculty Publications and Presentations

We characterized wildfire transmission and exposure within a matrix of large land tenures (federal, state, and private) surrounding 56 communities within a 3.3 million ha fire prone region of central Oregon US. Wildfire simulation and network analysis were used to quantify the exchange of fire among land tenures and communities and analyze the relative contributions of human versus natural ignitions to wildfire exposure. Among the land tenures examined, the area burned by incoming fires averaged 57% of the total burned area. Community exposure from incoming fires ignited on surrounding land tenures accounted for 67% of the total area burned. The …

The Influence Of Föhn Winds On Glacial Lake Washburn And Palaeotemperatures In The Mcmurdo Dry Valleys, Antarctica, During The Last Glacial Maximum, Maciej Obryk, Peter Doran, Ed Waddington, Chris Mckay

Geology Faculty Publications and Presentations

Large glacial lakes, including Glacial Lake Washburn, were present in the McMurdo Dry Valleys, Antarctica, during the Last Glacial Maximum (LGM) despite a colder and drier climate. To address the mechanism capable of generating enough meltwater to sustain these large lakes, a conceptual model was developed based on the warming potential of infrequent contemporary föhn winds. The model suggests that föhn winds were capable of generating enough meltwater to sustain large glacial lakes during the LGM by increasing degree days above freezing (DDAF) and prolonging the melt season. A present-day relationship between infrequent summer föhn winds and DDAF was established. …

Ground-Rupturing Earthquakes On The Northern Big Bend Of The San Andreas Fault, California, 800 A.D. To Present, Katherine Scharer, Ray J. Weldon Ii, Glenn Biasi, Ashley Streig, Thomas Fumal

Geology Faculty Publications and Presentations

Paleoseismic data on the timing of ground-rupturing earthquakes constrain the recurrence behavior of active faults and can provide insight on the rupture history of a fault if earthquakes dated at neighboring sites overlap in age and are considered correlative. This study presents the evidence and ages for 11 earthquakes that occurred along the Big Bend section of the southern San Andreas Fault at the Frazier Mountain paleoseismic site. The most recent earthquake to rupture the site was the Mw7.7–7.9 Fort Tejon earthquake of 1857. We use over 30 trench excavations to document the structural and sedimentological evolution of a small …

Some Remarks On Interpolation And Best Approximation, Randolph E. Bank, Jeffrey S. Ovall

Mathematics and Statistics Faculty Publications and Presentations

Sufficient conditions are provided for establishing equivalence between best approximation error and projection/interpolation error in finite-dimensional vector spaces for general (semi)norms. The results are applied to several standard finite element spaces, modes of interpolation and (semi)norms, and a numerical study of the dependence on polynomial degree of constants appearing in our estimates is provided.