Physical Sciences and Mathematics Commons^™

The Art And Science Of Weed Mapping, David T. Barnett, Thomas J. Stohlgren, Catherine S. Jarnevich, Geneva W. Chong, Jenny A. Ericson, Tracy R. Davern, Sara E. Simonson

United States Geological Survey: Staff Publications

Land managers need cost-effective and informative tools for non-native plant species management. Many local, state, and federal agencies adopted mapping systems designed to collect comparable data for the early detection and monitoring of non-native species. We compared mapping information to statistically rigorous, plot-based methods to better understand the benefits and compatibility of the two techniques. Mapping non-native species locations provided a species list, associated species distributions, and infested area for subjectively selected survey sites. The value of this information may be compromised by crude estimates of cover and incomplete or biased estimations of species distributions. Incorporating plot-based assessments guided by …

The Laplacian In Spherical Polar Coordinates, Carl W. David

Chemistry Education Materials

The transformation between Cartesian and Spherical Polar coordinates of the Laplacian is carried out analytically, including two different Maple implementations of the same transformation.

Correlation Effects And Electronic Structure Of Gd@C60, Renat F. Sabirianov, Wai-Ning Mei, Jing Lu, Yi Gao, Xiao Cheng Zeng, Robert D. Bolskar, P. Jeppson, Ning Wu, A. N. Caruso, Peter Dowben

Physics Faculty Publications

We have investigated the electronic structure of Gd@C60 using ab initio calculations, photoemission and resonant photoemission (constant initial state spectroscopy). In comparing our calculations based on the local spin density approximation and the Hubbard model description with the observed photoemission spectra, we conclude that Gd 4f states exhibit enhanced correlation energies. These correlation energies have values larger than those normally observed in metallic gadolinium and gadolinium compounds. We attributed the enhanced correlation to the diminished screening of the encapsulated Gd. Both calculation and experiment confi rm a strong hybridization between the valence states of Gd and the C 2p states …

Invasive Predators: A Synthesis Of The Past, Present, And Future, William C. Pitt, Gary W. Witmer

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive predators have had devastating effects on species around the world and their effects are increasing. Successful invasive predators typically have a high reproductive rate, short generation times, a generalized diet, and are small or secretive. However, the probability of a successful invasion is also dependent on the qualities of the ecosystem invaded. Ecosystems with a limited assemblage of native species are the most susceptible to invasion provided that habitat and climate are favorable. In addition, the number of invasion opportunities for a species increases the likelihood that the species will successfully establish. The list of routes of entry or …

Electrochemical Impedance Spectroscopy To Evalutate The Effects Of Ph Variations And Ionic Self-Assembly On Undecanoic Acid Monolayers Immobilized On Gold, Mark Anderson, Wesley Sanders

Mark R. Anderson

No abstract is currently available.

Entrainment And Stimulated Emission Of Auto-Oscillators In An Acoustic Cavity, Richard L. Weaver, Oleg I. Lobkis, Alexey Yamilov

Physics Faculty Research & Creative Works

We report theory, measurements and numerical simulations on nonlinear piezoelectric ultrasonic devices with stable limit cycles. The devices are shown to exhibit behavior familiar from the theory of coupled auto-oscillators. Frequency of auto-oscillation is affected by the presence of an acoustic cavity as these spontaneously emitting devices adjust their frequency to the spectrum of the acoustic cavity. Also, the auto-oscillation is shown to be entrained by an applied field; the oscillator synchronizes to an incident wave at a frequency close to the natural frequency of the limit cycle. It is further shown that synchronization occurs here with a phase that …

Recollision Dynamics And Time Delay In Strong-Field Double Ionization, Stanley L. Haan, L. Breen, A. Karim, Joseph H. Eberly

University Faculty Publications and Creative Works

Three-dimensional classical ensembles are employed to study recollision dynamics in double ionization of atoms by 780-nm intense lasers. After recollision one electron typically remains bound to the atom for a portion of a laser cycle, during which time the nucleus strongly influences its direction of motion. The electron then escapes over a suppressed barrier, with its final momentum depending critically on the laser phase at escape. The other electron remains unbound after collision, and typically drifts out in a momentum hemisphere opposite from its motion just after the collision. Several example trajectories at intensity 0.4 PW/cm2 with various time delays …

The Relationship Between Discrete Vector Quantization And The P-Median Problem, Allen G. Holder, G Lim, J Reese

Mathematics Faculty Research

We show that a well studied problem in the engineering community is the same as a problem studied by mathematical combinatorialists. Specifically, we show that the question of optimally designing a vector quantizer, which is an important problem in coding theory, is the same as the p-median problem, which is a classic graph theory problem with important applications in operations research. The importance of the relationship lies in the fact that both communities have spent years developing solution methodologies, and this connection permits each community to glean new ideas from the other. We show that two of the most popular …

El Staff Presidencial En México. Del Secretario Particular A Las Oficinas De La Presidencia, J. R. Joel Flores-Mariscal

J. R. Joel Flores-Mariscal

No abstract provided.

Performance Evaluation For Hybrid Architectures, Praveen Krishnamurthy

All Computer Science and Engineering Research

In this dissertation we discuss methologies for estimating the performance of applications on hybrid architectures, systems that include various types of computing resources (e.g. traditional general-purpose processors, chip multiprocessors, reconfigurable hardware). A common use of hybrid architectures will be to deploy coarse pipeline stages of application on "suitable" compute units with communication path for transferring data. The first problem we focus on relates to the sizing the data queues between the different processing elements of an hybrid system. Much of the discussion centers on our analytical models that can be used to derive performance metrics of interest such as, throughput …

Oral Rabies Vaccine (Orv) Bait Uptake By Captive Striped Skunks, Susan M. Jojola, Stacie J. Robinson, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Aerial delivery of oral rabies vaccine (ORV) baits has proven effective in large-scale efforts to immunize wildlife against rabies, and in North America this strategy currently is being used to immunize foxes (Urocyon cinereoargenteus and Vulpes vulpes), raccoons (Procyon lotor), and coyotes (Canis latrans). Skunks are also a major reservoir and vector of rabies, but at present oral vaccines for use in skunks are not licensed. Furthermore, given differences in morphology (smaller jaws) and behavior (food handling and consumption), it is unknown if baits currently used in ORV campaigns would be effective for skunks. …

Effect Of Surrounding Point Charges On The Density Functional Calculations Of NiXOX Clusters (X = 4–12), Evgueni B. Kadossov, Karen J. Gaskell, Marjorie Langell

Marjorie A. Langell Publications

Embedded Ni_xO_x clusters (x = 4–12) have been studied by the density-functional method using compensating point charges of variable magnitude to calculate the ionic charge, bulk modulus, and lattice binding energy. The computations were found to be strongly dependent on the value of the surrounding point charge array and an optimum value could be found by choosing the point charge to reproduce the experimentally observed Ni–O lattice parameter. This simple, empirical method yields a good match between computed and experimental data, and even small variation from the optimum point charge value produces significant deviation between computed …

Dynamic Energy Aware Task Scheduling Using Run-Queue Peek, Sachin Pawaskar, Hesham Ali

Computer Science Faculty Proceedings & Presentations

Scheduling dependent tasks is one of the most challenging problems in parallel and distributed systems. It is known to be computationally intractable in its general form as well as several restricted cases. An interesting application of scheduling is in the area of energy awareness for mobile battery operated devices where minimizing the energy utilized is the most important scheduling policy consideration. A number of heuristics have been developed for this consideration. In this paper, we study the scheduling problem for a particular battery model. In the proposed work, we show how to enhance a well know approach of accounting for …

Nonvolatile Two-Terminal Molecular Memory, Jason Snodgrass, Glen Kennedy, Wai-Ning Mei, Renat F. Sabirianov

Physics Faculty Proceedings & Presentations

We propose a nonvolatile two-terminal memory with two resistance states based on the molecular tunnel junctions. This tunnel junction is composed of one or few monolayers of polar molecules sandwiched between two electrodes made of materials with different screening length. As a prototype model system we study rare earth endohedral metallofullerene molecule with reversible dipole moment sandwiched by metal and semiconducting electrodes forming a double barrier junction. We use the Thomas-Fermi model to calculate the potential profile across the device. Calculated tunneling conductance through the proposed structure changes by order of magnitude upon the reversal of the dipole orientation (due …

Water Current, Volume 39, No. 1. Winter 2007

Water Current Newsletter

Contents

• Future of Water Use in Agriculture Topic of Fourth Annual Water Law, Policy and Science Conference by Steve Ress

• June Water Tour to New Mexico Compares Republican and Pecos River Compacts By Steve Ress

• From the Director

• Meet the Faculty

• EPAGrant Helps Researchers Study Feedlot Waste Impacts by Steve Ress

• Lawmakers Get Briefings on Top Water Issues by Jessica Harder

• UNL Hosts Biofuels and Water Resources Retreat By Steve Ress

• Fish and Wildlife Coop Supports Students, Lends Assistance by Brent Atema

• UNL Land Purchase Will Help Farmers and Ranchers Deal …

Place A Graduate For God, Verlyn R. Benson

Public Document Archive

Dean's Letter #01 from the College of Technology, distributed in February, 2007.

Variational Principles For Set-Valued Mappings With Applications To Multiobjective Optimization, Truong Q. Bao, Boris S. Mordukhovich

Mathematics Research Reports

This paper primarily concerns the study of general classes of constrained multiobjective optimization problems (including those described via set-valued and vector-valued cost mappings) from the viewpoint of modern variational analysis and generalized differentiation. To proceed, we first establish two variational principles for set-valued mappings, which~being certainly of independent interest are mainly motivated by applications to multiobjective optimization problems considered in this paper. The first variational principle is a set-valued counterpart of the seminal derivative-free Ekeland variational principle, while the second one is a set-valued extension of the subdifferential principle by Mordukhovich and Wang formulated via an appropriate subdifferential notion for …

The Distribution Of Silicate Strength In Spitzer Spectra Of Agns And Ulirgs, Lei Hao, D. W. Weedman, H. Spoon, J. A. Marshall, N. A. Levenson, Moshe Elitzur, J. R. Houck

Physics and Astronomy Faculty Publications

A sample of 196 AGNs and ULIRGs observed by the Infrared Spectrograph (IRS) on Spitzer is analyzed to study the distribution of the strength of the 9.7 μm silicate feature. Average spectra are derived for quasars, Seyfert 1 and Seyfert 2 AGNs, and ULIRGs. We find that quasars are characterized by silicate features in emission and Seyfert 1s equally by emission or weak absorption. Seyfert 2s are dominated by weak silicate absorption, and ULIRGs are characterized by strong silicate absorption (mean apparent optical depth about 1.5). Luminosity distributions show that luminosities at rest frame 5.5 μm are similar …

Integrated Fisheries Management Allocation Report Western Rock Lobster Resource, Integrated Fisheries Allocation Advisory Committee

Fisheries management papers

This report, prepared by the Integrated Fisheries Allocation Advisory Committee (IFAAC), contains the committee’s advice and recommendations to the Minister for Fisheries on allocations for the western rock lobster resource. The setting of explicit allocations to sectors (Customary, recreational and commercial) is integral to Integrated Fisheries Management (IFM) in Western Australia.

State-Of-The-Art: Interaktion In Erweiterten Realitäten, Philipp Schaer, Marco Thum

Philipp Schaer

Die folgende Arbeit soll einen Überblick über bestehende Lösungen zur Interaktion in Erweiterten Realitäten (Augmented Reality) schaffen. Hierzu werden anhand dreier grundlegender Betrachtungsweisen unterschiedliche Interaktionskonzepte und -umsetzungen sowohl von der technischen, als auch von der konzeptuellen Seite her, vorgestellt. Neben Fragen der Visualisierung werden unterschiedliche Typen von Benutzungsschnittstellen vorstellt. Den größten Teil nehmen die drei typischen Interaktionsaufgaben Selektion- und Manipulation, Navigation und Systemkontrolle und die damit verbundenen Interaktionstechniken ein. Die Inhalte des Arbeitsberichts beschränken sich auf den Einsatz von Interaktionelementen in Augmented Reality Umgebungen. Dies geschieht in Abgrenzung zu Forschungsarbeiten auf dem Gebiet zu Interaktionstechniken in Virtual Reality Umgebungen (vollimmersiv …

Supervised Detection Of Conserved Motifs In Dna Sequences With Cosmo, Oliver Bembom, Sunduz Keles, Mark J. Van Der Laan

Oliver Bembom

A number of computational methods have been proposed for identifying transcription factor binding sites from a set of unaligned sequences that are thought to share the motif in question. We here introduce an algorithm, called cosmo, that allows this search to be supervised by specifying a set of constraints that the position weight matrix of the unknown motif must satisfy. Such constraints may be formulated, for example, on the basis of prior knowledge about the structure of the transcription factor in question. The algorithm is based on the same two-component multinomial mixture model used by MEME, with stronger reliance, however, …

The Causal Effect Of Recent Leisure-Time Physical Activity On All-Cause Mortality Among The Elderly, Oliver Bembom, Mark J. Van Der Laan, Ira B. Tager

Oliver Bembom

We analyze data collected as part of a prospective cohort study of elderly people living in and around Sonoma, CA, in order to estimate, for each round of interviews, the causal effect of leisure-time physical activity (LTPA) over the past year on the risk of mortality in the following two years. For each round of interviews, this effect is estimated separately for subpopulations defined based on past exercise habits, age, and whether subjects have had cardiac events in the past. This decomposition of the original longitudinal data structure into a series of point-treatment data structures corresponds to an application of …

An Unexpected Limit Of Expected Values, Branko Ćurgus, Robert I. Jewett

Mathematics Faculty Publications

Let t⩾0. Select numbers randomly from the interval [0,1] until the sum is greater than t . Let α(t) be the expected number of selections. We prove that α(t)=e^t for 0⩽t⩽1. Moreover, . This limit is a special case of our asymptotic results for solutions of the delay differential equation f^′(t)=f(t)-f(t-1) for t>1. We also consider four other solutions of this equation that are related to the above selection process.

Basic Research Needs For Geosciences: Facilitating 21st Century Energy Systems, U.S. Department Of Energy, Office Of Basic Energy Sciences, Donald J. Depaolo, Franklin M. Orr Jr.

Publications (YM)

Executive Summary

Serious challenges must be faced in this century as the world seeks to meet global energy needs and at the same time reduce emissions of greenhouse gases to the atmosphere. Even with a growing energy supply from alternative sources, fossil carbon resources will remain in heavy use and will generate large volumes of carbon dioxide (CO₂). To reduce the atmospheric impact of this fossil energy use, it is necessary to capture and sequester a substantial fraction of the produced CO₂. Subsurface geologic formations offer a potential location for long-term storage of the requisite large …

People-Centric Urban Sensing: Security Challenges For The New Paradigm, Peter Johnson, Apu Kapadia, David Kotz, Nikos Triandopoulos

Computer Science Technical Reports

We study the security challenges that arise in \emph{people-centric urban sensing}, a new sensor-networking paradigm that leverages humans as part of the sensing infrastructure. Most prior work on sensor networks has focused on collecting and processing ephemeral data about the environment using a static topology and an application-aware infrastructure. People-centric urban sensing, however, involves collecting, storing, processing and fusing large volumes of data related to every-day human activities. Sensing is performed in a highly dynamic and mobile environment, and supports (among other things) pervasive computing applications that are focused on enhancing the user's experience. In such a setting, where humans …

Replica Exchange With Dynamical Scaling, Steven W. Rick

Chemistry Faculty Publications

A replica exchange method is presented which requires fewer replicas and is designed to be used for large systems. In this method, dynamically scaled replicas are placed between conventional replicas at broadly spaced temperatures. The potential of the scaled replicas is linearly scaled by a dynamicalvariable which varies between 0 and 1. When the variable is near either end point the replica can undergo exchanges with one of its neighboring replicas. Two different versions of the method are presented for a model system of a small peptide in water. The scaled replica can replace manyreplicas and the method can be …

Galois Number Fields With Small Root Discriminant, John W. Jones, David P. Roberts

Mathematics Publications

We pose the problem of identifying the set K(G,Ω) of Galois number fields with given Galois group G and root discriminant less than the Serre constant Ω ≈ 44.7632. We definitively treat the cases G = A₄. A₅, A₆, and S₄, S₅, S₆, finding exactly 59, 78, 5 and 527, 192, 13 fields, respectively. We present other fields with Galois groups SL₃(2), A₇, S₇, PGL₂(7), SL₂(8), ΣL₂(8), PGL₂(9), PSL₂(11), and …

Cosmogenic 10be And 36cl Ages From Late Pleistocene Terminal Moraine Complexes In The Taylor River Drainage Basin, Central Colorado, U.S.A., Keith A. Brugger

Geology Publications

Cosmogenic surface-exposure ages from boulders on a terminal moraine complex establish the timing of the local last glacial maximum (LGM) in the Taylor River drainage basin, central Colorado. Five zero-erosion ¹⁰Be ages have a mean of 19.5±1.8 ka while that for three ³⁶Cl ages is 20.7±2.3 ka. Corrections for modest rates (∼1 mm ka⁻¹) of boulder surface erosion result in individual and mean ages that are generally within 2% of their zero-erosion values. Both the means and the range in ages of individual boulders are consistent with those reported for late Pleistocene moraines elsewhere in the …

Step-Up Simultaneous Tests For Identifying Active Effects In Orthogonal Saturated Designs, Samuel S. Wu, Weizhen Wang

Mathematics and Statistics Faculty Publications

A sequence of null hypotheses regarding the number of negligible effects (zero effects) in orthogonal saturated designs is formulated. Two step-up simultaneous testing procedures are proposed to identify active effects (nonzero effects) under the commonly used assumption of effect sparsity. It is shown that each procedure controls the experimentwise error rate at a given alpha level in the strong sense.

Density Matrix, Ronald Lovett

Topics in Quantum Mechanics

No abstract provided.