Physical Sciences and Mathematics Commons^™

A Multiscale And Multidisciplinary Investigation Of Ecosystem- Atmosphere Co2 Exchange Over The Rocky Mountains Of Colorado, Jielun Sun, Steven Oncley, Sean Burns, Britton Stephens, Donald Lenschow, Teresa Campos, Russell Monson, David Schimel, William Sacks, Stephan Dewekker, Chun-Ta Lai, Brian Lamb, Dennis Ojima, Patrick Ellsworth, Leonel Sternberg, Sharon Zhong, Craig Clements, David Moore, Dean Anderson, Andrew Watt, Jia Hu, Mark Tschudi, Steven Aulenbach, Eugene Allwine, Teresa Coons

Faculty Publications, Meteorology and Climate Science

A significant fraction of Earth consists of mountainous terrain. However, the question of how to monitor the surface–atmosphere carbon exchange over complex terrain has not been fully explored. This article reports on studies by a team of investigators from U.S. universities and research institutes who carried out a multiscale and multidisciplinary field and modeling investigation of the CO2 exchange between ecosystems and the atmosphere and of CO2 transport over complex mountainous terrain in the Rocky Mountain region of Colorado. The goals of the field campaign, which included ground and airborne in situ and remote-sensing measurements, were to characterize unique features …

Abundance Of Ammonia-Oxidizing Archaea And Bacteria Along An Estuarine Salinity Gradient In Relationship To Potential Nitrification Rates, Anne E. Bernhard, Zachary C. Landry, Alison Blevins, José R. De La Torre, Anne E. Giblin, David A. Stahl

Biology Faculty Publications

Abundance of ammonia-oxidizing Archaea (AOA) was found to be always greater than that of ammonia-oxidizing Bacteria along an estuarine salinity gradient, and AOA abundance was highest at intermediate salinity. However, AOA abundance did not correlate with potential nitrification rates. This lack of correlation may be due to methodological limitations or alternative energy sources.

Adaptive Control Of Modal Properties Of Optical Beams Using Photothermal Effects, Muzammil A. Arain, William Z. Korth, Luke F. Williams, Rodica Martin, Guido Mueller, D. B. Tanner, David H. Reitze

Department of Physics and Astronomy Faculty Scholarship and Creative Works

We present an experimental demonstration of adaptive control of modal properties of optical beams. The control is achieved via heat-induced photothermal actuation of transmissive optical elements. We apply the heat using four electrical heaters in thermal contact with the element. The system is capable of controlling both symmetrical and astigmatic aberrations providing a powerful means for in situ correction and control of thermal aberrations in high power laser systems. We demonstrate a tunable lens with a focusing power varying from minus infinity to -10 m along two axes using SF57 optical glass. Applications of the proposed system include laser material …

Enhanced Metric Regularity And Lipschitzian Properties Of Variational Systems, Francisco J. Aragón Artacho, Boris S. Mordukhovich

Mathematics Research Reports

This paper mainly concerns the study of a large class of variational systems governed by parametric generalized equations, which encompass variational and hemivariational inequalities, complementarity problems, first-order necessary optimality conditions, and other optimization-related models important for optimization theory and applications. An efficient approach to these issues has been developed in our preceding work [1] establishing qualitative and quantitative relationships between conventional metric regularity jsubregularity and Lipschitzian/calmness properties in the framework of parametric generalized equations in arbitrary Banach spaces. This paper provides, on one hand, significant extensions of the major results in [1] to new partial metric regularity and hemiregularity properties. …

Estimation Of P[Y X] For Generalized Pareto Distribution, Manijeh Mahmoodi, Sadegh Rezaei, Rasool Tahmasbi

manijeh mahmoodi

No abstract provided.

Investigation Of Deactivation Of Transition Metal Oxide Catalysts Supported On Γ-Al2o3 During Catalytic Oxidation Of Some Oxygen Containing Vocs In A Tubular Reactor, Hosein Afshary

Hosein Afshary

It is necessary to decrease the emission of Volatile organic compound ( VOCs ) to air and among of all destructive techniques used for decreasing these compounds, Catalytic Oxidation is considered a suitable technique but deactivation of catalysts through catalytic processes is one of the major problems and most be studied. In this Project, at First, gamma alumina supported metal oxide catalysts were made and also industrial Pt catalyst was prepared. Then structure of these catalysts was studied using XRD, SEM and FT-IR techniques. These techniques approved the nanostructure of catalysts. The amount of supported metals in each catalyst was …

Improved Automated Monitoring And New Analysis Algorithm For Circadean Phototaxis Rhythms In Chlamydomonas, Christa Gaskill, Jennifer Forbes-Stovall, Bruce Kessler, Mike Young, Claire A. Rinehart, Sigrid Jacobshagen

Bruce Kessler

Automated monitoring of circadian rhythms is an efficient way of gaining insight into oscillation parameters like period and phase for the underlying pacemaker of the circadian clock. Measurement of the circadian rhythm of phototaxis (swimming towards light) exhibited by the green alga Chlamydomonas reinhardtii has been automated by directing a narrow and dim light beam through a culture at regular intervals and determining the decrease in light transmittance due to the accumulation of cells in the beam. In this study, the monitoring process was optimized by constructing a new computercontrolled measuring machine that limits the test beam to wavelengths reported …

Doe Request For Information (Rfi) De-Foa-0000153 Pv Manufacturing Initiative: Summary Report, National Renewable Energy Laboratory

Publications (E)

Clean Cities hosts a collection of tools on the exploring concepts for a “PV Manufacturing Initiative” to facilitate the development of a strong photovoltaic (PV) manufacturing industry in the United States. As an integral part this effort, and to inform the creation of a new funding opportunity in this area, DOE sought feedback from the PV industry.

This document summarizes the results of the PV Manufacturing Request for Information (RFI), DE-FOA-0000153. (See Attachment 1.) The RFI was posted on http://www.grants.gov on 4 September 2009 and the NREL Web site on 9 September 2009. Respondents were asked to submit RFI inputs …

Our Places To Tell Stories: Preliminary Program Springs Preserve, Public Lands Institute

Our Places to Tell Stories

Our Places Tell Stories is an innovative conference for educators and others working at public lands, schools, nature centers, museums, zoos, aquaria, and all nature and heritage rich places.

This list of presentations represents a preliminary program of sessions. A final program will be emailed to all registrants prior to the conference. Thank you for your interest, and we look forward to seeing you at the Springs!

A Stochastic Model Of Cell Cycle Desynchronization, Peter Olofsson, Thomas O. Mcdonald

Mathematics Faculty Research

A general branching process model is suggested to describe cell cycle desynchronization. Cell cycle phase times are modeled as random variables and a formula for the expected fraction of cells in S phase as a function of time is established. The model is compared to data from the literature and is also compared to previously suggested deterministic and stochastic models.

Proton Disorder And The Dielectric Constant Of Type Ii Clathrate Hydrates, Steven W. Rick

Chemistry Faculty Publications

Computational studies are presented examining the degree of proton disorder in argon and molecular hydrogen sII clathrate hydrates. Results are presented using a variety of model potentials for the dielectric constant, the proton order parameter, and the molecular volume for the clathrate systems. The dielectric constant for the clathrate systems is found to be lower than the dielectric constant of ice in all models. The ratio of the clathrate to ice dielectric constant correlates well with the ratio of the densities, which is not the case for comparisons to the liquid, so that differences in the dielectric constants between ice …

Integer Functions On The Cycle Space And Edges Of A Graph, Dan Slilaty

Mathematics and Statistics Faculty Publications

A directed graph has a natural Z-module homomorphism from the underlying graph’s cycle space to Z where the image of an oriented cycle is the number of forward edges minus the number of backward edges. Such a homomorphism preserves the parity of the length of a cycle and the image of a cycle is bounded by the length of that cycle. Pretzel and Youngs (SIAM J. Discrete Math. 3(4):544–553, 1990) showed that any Z-module homomorphism of a graph’s cycle space to Z that satisfies these two properties for all cycles must be such a map induced from an edge direction …

Magnetic Properties Of The Quasi-Two-Dimensional S=1/2 Heisenberg Antiferromagnet [Cu(Pyz)(2)(Hf2)]Pf6, E Cizmar, S A. Zvyagin, R Beyer, M Uhlarz, M Ozerov, Y Skourski, Jamie L. Manson, J A. Schlueter, J Wosnitza

Chemistry and Biochemistry Faculty Publications

We report on high-field magnetization, specific heat, and electron-spin-resonance (ESR) studies of the quasi-two-dimensional spin-1/2 Heisenberg antiferromagnet [Cu(pyz)(2)(HF2)]PF6. The frequency-field diagram of ESR modes below T-N=4.38 K is described in the frame of the mean-field theory, confirming a collinear magnetic structure with an easy-plane anisotropy. The obtained results allowed us to determine the anisotropy/exchange interaction ratio, A/J=0.003, and the upper limit for the interplane/intraplane exchange interaction ratio, J'/J=1/16. It is argued that despite the onset of three-dimensional long-range magnetic ordering the magnetic properties of this material (including high-magnetic-field magnetization and nonmonotonic field dependence of the Neel temperature) are strongly affected …

Mobility Analysis Of Highly Conducting Thin Films: Application To Zno, David C. Look, K. D. Leedy, D. H. Tomich, B. Bayraktaroglu

Physics Faculty Publications

Hall-effect measurements have been performed on a series of highly conductive thin films of Ga-doped ZnO grown by pulsed laser deposition and annealed in a forming-gas atmosphere (5% H₂ in Ar). The mobility as a function of thickness d is analyzed by a simple formula involving only ionized-impurity and boundary scattering and having a single fitting parameter, the acceptor/donor concentration ratio K = N_A/N_D. For samples with d = 3–100 nm, K_avg = 0.41, giving N_D = 4.7×10²⁰ and N_A = 1.9×10²⁰ cm⁻³. Thicker samples require a …

Corot-7b: Super-Earth Or Super-Io?, Rory Barnes, Sean N. Raymond, Richard Greenberg, Brian Jackson, Nathan A. Kaib

Brian Jackson

CoRoT-7b, a planet about 70% larger than the Earth orbiting a Sun-like star, is the first-discovered rocky exoplanet, and hence has been dubbed a "super-Earth." Some initial studies suggested that since the planet is so close to its host star, it receives enough insolation to partially melt its surface. However, these past studies failed to take into consideration the role that tides may play in this system. Even if the planet's eccentricity has always been zero, we show that tidal decay of the semimajor axis could have been large enough that the planet formed on a wider orbit which received …

The Influence Of Partial Timber Harvesting In Riparian Buffers On Macroinvertebrate And Fish Communities In Small Streams In Minnesota, Usa, Christopher J. Chizinski, Bruce Vondracek, Charles R. Blinn, Raymond M. Newman, Dickson M. Atuke, Keith Fredricks, Nathaniel A. Hemstad, Eric Merten, Nicholas Schlesser

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Relatively few evaluations of aquatic macroinvertebrate and fish communities have been published in peer-reviewed literature detailing the effect of varying residual basal area (RBA) after timber harvesting in riparian buffers. Our analysis investigated the effects of partial harvesting within riparian buffers on aquatic macroinvertebrate and fish communities in small streams from two experiments in northern Minnesota northern hardwood-aspen forests. Each experiment evaluated partial harvesting within riparian buffers. In both experiments, benthic macroinvertebrates and fish were collected 1 year prior to harvest and in each of 3 years after harvest. We observed interannual variation for the macroinvertebrate abundance, diversity and taxon …

The Location Decisions Of Foreign Investors In China: Untangling The Effect Of Wages Using A Control Function Approach, Xuepeng Liu, Mary E. Lovely, Jan Ondrich

Faculty Articles

There is almost no support for the proposition that capital is attracted to low wages from firm-level studies. We examine the location choices of 2,884 firms investing in China between 1993 and 1996 to offer two main contributions. First, we find that the location of labor-intensive activities is highly elastic to provincial wage differences. Generally, investors' wage sensitivity declines as the skill intensity of the industry increases. Second, we find that unobserved location-specific attributes exert a downward bias on estimated wage sensitivity. Using a control function approach, we estimate a downward bias of 50% to 90% in wage coefficients estimated …

Quantum Griffiths Phase In The Weak Itinerant Ferromagnetic Alloy Ni₁₋ₓvₓ, Sara Ubaid-Kassis, Thomas Vojta, Almut Schroeder

Physics Faculty Research & Creative Works

We present magnetization (M) data of the d-metal alloy Ni_1-xV_x at vanadium concentrations close to x_x ~ 11.4% where the onset of long-range ferromagnetic (FM) order is suppressed to zero temperature. Above x_c, the temperature (T) and magnetic field (H) dependencies of the magnetization are best described by simple nonuniversal power laws. the exponents of M/H ~ T ^γ and M ~ H^α are related by 1-γ=α for wide temperature (10c to γ<0.1 for x=15%. This behavior is not compatible with either classical or quantum critical behavior in a clean 3D FM. Instead it closely follows the predictions for a quantum Griffiths phase associated with a quantum phase transition in a disordered metal. Deviations at the lowest temperatures hint at a freezing of large clusters and the onset of a cluster glass phase.

Astronomy's New Messengers: A Traveling Exhibit On Gravitational-Wave Physics, Marco Cavaglia, Martin Hendry, Szabolcs Marka, David H. Reitze, Keith Riles

Physics Faculty Research & Creative Works

The Laser Interferometer Gravitational-wave Observatory exhibit Astronomy's New Messengers: Listening to the Universe with Gravitational Waves is traveling to colleges, universities, museums and other public institutions throughout the United States. Astronomy's New Messengers primarily communicates with an adolescent and young adult audience, potentially inspiring them into the field of science. Acknowledging that this audience is traditionally a difficult one to attract, the exhibit publicly announces itself in a charismatic fashion to reach its principal goals of broadening the community of people interested in science and encouraging interest in science among young people.

A Majorization Algorithm For Constrained Correlation Matrix Approximation, Daniel J. Simon, Jeff Abell

Electrical and Computer Engineering Faculty Publications

We desire to find a correlation matrix of a given rank that is as close as possible to an input matrix R, subject to the constraint that specified elements in must be zero. Our optimality criterion is the weighted Frobenius norm of the approximation error, and we use a constrained majorization algorithm to solve the problem. Although many correlation matrix approximation approaches have been proposed, this specific problem, with the rank specification and the constraints, has not been studied until now. We discuss solution feasibility, convergence, and computational effort. We also present several examples.

Applying A Molecular Genetics Approach To Shark Conservation And Management: Assessment Of Dna Barcoding In Hammerhead Sharks And Global Population Genetic Structuring In The Gray Reef Shark, Carcharhinus Amblyrhynchos., Rebekah L. Horn

HCNSO Student Theses and Dissertations

Chapter 1

DNA barcoding based on the mitochondrial cytochrome c oxidase subunit I (COI) gene sequence is emerging as a useful tool for identifying unknown, whole or partial organisms to species level. However, the application of only a single mitochondrial marker for robust species identification has also come under some criticism due to the possibility of erroneous identifications resulting from species hybridizations and/or the potential presence of nuclear-mitochondrial psuedogenes. The addition of a complementary nuclear DNA barcode has therefore been widely recommended to overcome these potential COI gene limitations, especially in wildlife law enforcement applications where greater confidence in the …

Twitterrank: Finding Topic-Sensitive Influential Twitterers, Jianshu Weng, Ee Peng Lim, Jing Jiang, Qi He

Research Collection School Of Computing and Information Systems

This paper focuses on the problem of identifying influential users of micro-blogging services. Twitter, one of the most notable micro-blogging services, employs a social-networking model called "following", in which each user can choose who she wants to "follow" to receive tweets from without requiring the latter to give permission first. In a dataset prepared for this study, it is observed that (1) 72.4% of the users in Twitter follow more than 80% of their followers, and (2) 80.5% of the users have 80% of users they are following follow them back. Our study reveals that the presence of "reciprocity" can …

Characteristics Of Co₂ Sequestration In Saline Aquifers, Fang Yang, Baojun Bai, Dazhen Tang, Shari Dunn-Norman, David J. Wronkiewicz

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Storage of CO₂ in saline aquifers is a viable option for reducing the amount of CO₂ released to the atmosphere. This paper provides an overall review of CO₂ sequestration in saline aquifers. First, the principles of CO₂ sequestration are presented, including CO₂ phase behavior, CO₂-water-rock interaction, and CO₂ trapping mechanisms. Then storage capacity and CO₂ injectivity are discussed as the main determinants of the storage potential of saline aquifers. Next, a site section process is addressed considering basin characteristics, reservoir characteristics, and economic and social concerns. Three main procedures are then …

Revised Relative Abundance Estimates And Temporal Activity Of Bats At Three Great Lakes National Parks Based On Acoustic Data, Bruce W. Miller

United States National Park Service: Publications

Abstract

In this study, Miller re-analyzed acoustic bat data collected from June-August 2003 that was part of a baseline inventory of bat species in three national parks in the Lake Superior region. While the original study presented base-line data on the presence/absence of bat species in these parks, this reanalysis provides estimates of relative abundance and temporal activity of the identified species. Using a suite of recently developed acoustic analysis tools, Miller created species specific filters. This allowed parsing of calls from non-fragmented sequences and differentiate between two species, Myotis septentrionalis and Myotis lucifugus, that were combined into a …

Modern And Late Holocene Wind Regimes Over The Great Plains (Central U.S.A.), Rebecca L. Schmeisser, David B. Loope, Joseph A. Mason

Department of Earth and Atmospheric Sciences: Faculty Publications

The Great Plains of the central United States contain numerous presently stabilized dune fields that were active during the late Holocene. The most recent period of reactivation occurred about 700–1000 years ago during the Medieval Climatic Anomaly, a period of frequent, severe drought recognized throughout the North American West. Dune orientations and internal bedding preserve information about paleowinds from this time period. We compared paleowind information with modern winds and potential sand transport analyzed from meteorological data. While both reconstructed paleowinds and modern winds include a strong northwesterly component over the northern to central portions of the Great Plains, a …

A Novel Approach To Interarea Oscillation Damping By Unified Power Flow Controllers Utilizing Ultracapacitors, Mahyar Zarghami, Mariesa Crow, Jagannathan Sarangapani, Yilu Liu, Stan Atcitty

Electrical and Computer Engineering Faculty Research & Creative Works

This paper discusses a novel approach for damping interarea oscillations in a bulk power network using multiple unified power flow controllers (UPFCs) utilizing ultracapacitors, also known more generally as electrochemical capacitors (ECs). In this paper, a new control is introduced to mitigate interarea oscillations by directly controlling the UPFCs' sending and receiving bus voltages that better utilizes the stored energy in the ECs. The results of this controller are compared with and without ECs. The proposed control provides better interarea oscillation mitigation when applied to multiple UPFCs in the 118-bus IEEE test system.

Computer Software And Applications, Xiaoqing (Frank) Liu, Carl K. Chang, T. Ming Jiang

Computer Science Faculty Research & Creative Works

No abstract provided.

A Framework For Automated Enrichment Of Functionally Significant Inverted Repeats In Whole Genomes, Cyriac Kandoth, Fikret ErçAl, Ronald L. Frank

Computer Science Faculty Research & Creative Works

Background: RNA transcripts from genomic sequences showing dyad symmetry typically adopt hairpin-like, cloverleaf, or similar structures that act as recognition sites for proteins. Such structures often are the precursors of non-coding RNA (ncRNA) sequences like microRNA (miRNA) and small-interfering RNA (siRNA) that have recently garnered more functional significance than in the past. Genomic DNA contains hundreds of thousands of such inverted repeats (IRs) with varying degrees of symmetry. But by collecting statistically significant information from a known set of ncRNA, we can sort these IRs into those that are likely to be functional.

Results: A novel method was developed to …

Structural Investigations And Magnetic Properties Of Sol-Gel Ni0.5zn0.5fe2o4 Thin Films For Microwave Heating, Pengzhao Z. Gao, Evgeny V. Rebrov, Tiny M. W. G. M. Verhoeven, Jaap C. Schouten, Richard Kleismit, Gregory Kozlowski, John S. Cetnar, Zafer Turgut, Guru Subramanyam

Physics Faculty Publications

Nanocrystalline Ni_0.5Zn_0.5Fe₂O₄ thin films have been synthesized with various grain sizes by a sol-gel method on polycrystalline silicon substrates. The morphology, magnetic, and microwave absorption properties of the films calcined in the 673–1073 K range were studied with x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, vibrating sample magnetometry, and evanescent microwave microscopy. All films were uniform without microcracks. Increasing the calcination temperature from 873 to 1073 K and time from 1 to 3 h resulted in an increase of the grain size from 12 to 27 nm. The saturation …

Fishing Industry Impact Study : James Price Point Proposed Liquefied Natural Gas Precinct, Department Of Fisheries

Fisheries occasional publications

No abstract provided.