Physical Sciences and Mathematics Commons^™

Magnetic Order In The S=1/2 Two-Dimensional Molecular Antiferromagnet Copper Pyrazine Perchlorate Cu(Pz)(2)(Clo4)(2), T Lancaster, S J. Blundell, M L. Brooks, P J. Baker, F L. Pratt, Jamie L. Manson, M M. Conner, F Xiao, C P. Landee, F A. Chaves, S Soriano, M A. Novak, T P. Papageorgiou, A D. Bianchi, T Herrmannsdorfer, J Wosnitza, J A. Schlueter

Chemistry and Biochemistry Faculty Publications

We present an investigation of magnetic ordering in the two-dimensional S=1/2 quantum magnet Cu(Pz)(2)(ClO4)(2) using specific heat and zero-field muon-spin relaxation (mu+SR). The magnetic contribution to the specific heat is consistent with an exchange strength of 17.7(3) K. We find unambiguous evidence for a transition to a state of three-dimensional long-range order below a critical temperature T-N=4.21(1) K using mu+SR even though there is no feature in the specific heat at that temperature. The absence of a specific heat anomaly at T-N is consistent with recent theoretical predictions. The ratio of T-N/J=0.24 corresponds to a ratio of intralayer to interlayer …

Dominant Effect Of Near-Interface Native Point Defects On Zno Schottky Barriers, L. J. Brillson, H. L. Mosbacker, M. J. Hetzer, Y. Strzhemechny, David C. Look, G. Cantwell, J. Zhang, J. J. Song

Physics Faculty Publications

The authors used depth-resolved cathodoluminescence spectroscopy and current-voltage measurements to probe metal-ZnO diodes as a function of native defect concentration, oxygen plasma processing, and metallization. The results show that resident native defects in ZnO single crystals and native defects created by the metallization process dominate metal-ZnO Schottky barrier heights and ideality factors. Results for ZnO(0001) faces processed with room temperature remote oxygen plasmas to remove surface adsorbates and reduce subsurface native defects demonstrate the pivotal importance of crystal growth quality and metal-ZnO reactivity in forming near-interface states that control Schottky barrier properties.

The Evolution Of Zinjanthropus Boisei, Paul J. Constantino, Bernard A. Wood

Biological Sciences Faculty Research

Many people assume that OH 5, the type specimen of Paranthropus boisei, collected in 1959, was the first evidence of that taxon to be found, but OH 3, recovered in 1955, predated the discovery of OH 5 by four years. Thus, Paranthropus boisei recently celebrated the equivalent of its fiftieth birthday. This review marks that milestone by examining the way our understanding of this taxon has changed during its fifty, or so, year history.

Dynamics Of Asynchronous Random Boolean Networks With Asynchrony Generated By Stochastic Processes, Xutao Deng, Huimin Geng, Mihaela Teodora Matache

Mathematics Faculty Publications

An asynchronous Boolean network with N nodes whose states at each time point are determined by certain parent nodes is considered. We make use of the models developed by Matache and Heidel [Matache, M.T., Heidel, J., 2005. Asynchronous random Boolean network model based on elementary cellular automata rule 126. Phys. Rev. E 71, 026232] for a constant number of parents, and Matache [Matache, M.T., 2006. Asynchronous random Boolean network model with variable number of parents based on elementary cellular automata rule 126. IJMPB 20 (8), 897–923] for a varying number of parents. In both these papers the authors consider an …

The Time Invariance Principle, Ecological (Non)Chaos, And A Fundamental Pitfall Of Discrete Modeling, Bo Deng

Department of Mathematics: Faculty Publications

This paper is to show that most discrete models used for population dynamics in ecology are inherently pathological that their predications cannot be independently verified by experiments because they violate a fundamental principle of physics. The result is used to tackle an on-going controversy regarding ecological chaos. Another implication of the result is that all continuous dynamical systems must be modeled by differential equations. As a result it suggests that researches based on discrete modeling must be closely scrutinized and the teaching of calculus and differential equations must be emphasized for students of biology.

Lacustrine Evidence For Moisture Changes In The Nebraska Sand Hills During Marine Isotope Stage 3, Kimberly C. Jacobs, Sherilyn C. Fritz, James B. Swinehart

Department of Earth and Atmospheric Sciences: Faculty Publications

In the central Great Plains of North America, loess stratigraphy suggests that climate during the late Pleistocene was cold and dry. However, this record is discontinuous, and there are few other records of late-Pleistocene conditions. Cobb Basin, located on the northern edge of the Nebraska Sand Hills, contains lacustrine sediments deposited during Marine Isotope Stage 3, beginning approximately 45,000 cal yr BP and continuing for at least 10,000 yr. The lake was formed by a dune dam blockage on the ancient Niobrara River, and its deposits contain a diatom record that indicates changes through time in lake depth driven by …

Refuge Update – March/April 2007, Volume 4, Number 2

RefugeUpdate (USFWS-NWRS)

Table of Contents:
What’s Melting: Togiak Refuge Sizes Up Its Glaciers, page 3
Focus on Fish Conservation, pages 10-15
Whatever happened to…, pages 16-17
Wildlife Cooperatives, page 20

Molecular Dynamics Of Homogeneous Nucleation In The Vapor Phase Of Lennard-Jones. Iii. Effect Of Carrier Gas Pressure, Kenji Yasuoka, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

A molecular dynamics simulation of vapor phase nucleation has been performed with 40 000 Lennard-Jones particles for the target gas and 0–160 000 particles for the carrier gas. Three carrier gas models are adopted, including a soft-core model, a Lennard-Jones model, and a modified Lennard-Jones model in which the attractive interaction can be adjusted. The effect of the carrier-gas pressure is assessed through computing and comparing the rate of nucleation and cluster size distribution. It is found that the effect of the carrier-gas pressure can be strongly dependent on the carrier-gas model. A positive effect _enhancement of the nucleation rate_ …

Hydrogen Storage In Pillared Li-Dispersed Boron Carbide Nanotubes, Xiaojun Wu, Yi Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Ab initio density-functional theory study suggests that pillared Li-dispersed boron carbide nanotubes is capable of storing hydrogen with a mass density higher than 6.0 weight% and a volumetric density higher than 45 g/L. The boron substitution in carbon nanotube greatly enhances the binding energy of Li atom to the nanotube, and this binding energy (~ 2.7 eV) is greater than the cohesive energy of lithium metal (~1.7 eV), preventing lithium from aggregation (or segregation) at high lithium doping concentration. The adsorption energy of hydrogen on the Li-dispersed boron carbide nanotube is in the range of 10 – 24 kJ/mol, suitable …

Winning Paths In N-By-Infinity Hex, Walter Stromquist

Mathematics & Statistics Faculty Works

In n x ∞ Hex the player whose task is to complete a finite path can win, but the other player can ensure that any winning path contains at least n + [n−2/4] cells.

Efficient Algorithms For Machine Scheduling Problems With Earliness And Tardiness Penalties, Guang Feng, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

In this paper, we study the multi-machine scheduling problem with earliness and tardiness penalties and sequence dependent setup times. This problem can be decomposed into two subproblems—sequencing and timetabling. Sequencing focuses on assigning each job to a fixed machine and determine the job sequence on each machine. We call such assignment a semi-schedule. Timetabling focuses on finding an executable schedule from the semi-schedule via idle-time insertion. Sequencing is strongly NP-hard in general. Although timetabling is polynomial-time solvable, it can become a computational bottleneck if the procedure is executed many times within a larger framework. This paper makes two contributions. We …

Effects Of Configuration Interaction On The Alignment Of Beryllium-Like Ions, Andrey S. Surzhykov, Ulrich D. Jentschura, Th H. Stohlker, Stephan Fritzsche

Physics Faculty Research & Creative Works

The radiative electron capture into (initially) lithium-like ions is studied within the framework of the density matrix approach. Special attention is paid to the magnetic sublevel population of the residual ionic states which is described by a set of alignment parameters. Detailed calculations of these parameters have been performed for the capture into the 1s² 2s 3d_3/2 J_f2 level of high-Z ions along the beryllium isoelectronic sequence. We devote special attention to the modifications in the many-electron case as opposed to singleelectron systems. The electron correlation leads to an enhancement of the alignment, which becomes more …

Fragmentation Of Molecules By Fast Ion Impact, Christina Dimopoulou, Nicole Haag, Robert Moshammer, Pablo Daniel Fainstein, Alexander Dorn, M. Durr, Daniel Fischer, Joachim Hermann Ullrich

Physics Faculty Research & Creative Works

Single ionization of simple molecules, e.g. H₂, CO₂, by fast charged particle impact has been studied using a reaction microscope. By measuring the momenta of the emitted electron and the recoil ionic fragment in coincidence, channel-selective low-energy electron spectra have been recorded. The experimental cross sections will be presented, compared with the predictions of state-of-the-art CDW-EIS calculations and discussed in terms of molecular effects such as (i) autoionization and predissociation channels, (ii) interference patterns resulting from the two-center geometry of the diatomic molecule, in analogy to Young's double-slit experiment and (iii) dependence of the electron emission …

He I Emission In The Orion Nebula And Implications For Primordial Helium Abundance, R. L. Porter, Gary J. Ferland, K. B. Macadam

Physics and Astronomy Faculty Publications

We apply a recently developed theoretical model of helium emission to observations of both the Orion Nebula and a sample of extragalactic H II regions. In the Orion analysis, we eliminate some weak and blended lines and compare theory and observation for our reduced line list. With our best theoretical model we find an average difference between theoretical and observed intensities (I_pred/I_obs-1)=6.5%. We argue that both the red and blue ends of the spectrum may have been inadequately corrected for reddening. For the 22 highest quality lines, with 3499 Å≤λ≤6678 Å, our best model …

Mallard Brood Movements In The Canadian Prairie Parklands, Garnet H. Raven, Todd W. Arnold, David W. Howerter, Llwellyn M. Armstrong

The Prairie Naturalist

We radiotracked 308 mallard (Anas platyrhynchos) broods from hatching until 30 days of age Oij 15 study areas located throughout the Canadian Prairie Parklands to examine patterns of variation in movement frequency and distance. Broods moved an average of 350 m from nests to first wetlands (SO = 390), with 94% of broods moving less than I km. After leaving the nest, broods had a 23% probability of moving to a new wetland each day, but movement probability was a complex function of study area, hatch date, and ducking age, with younger and earlier-hatched broods exhibiting greater movement …

Woodland Bird Use Of In-Channel Islands In The Central Platte River, Nebraska, William C. Scharf

The Prairie Naturalist

Recapture data showed woodland obligate birds from riparian habitats made substantial use of thinly vegetated, adjacent small islands in the Platte River. During the bird nesting and spring migration seasons of 200 I through 2004, there were 4,360 individuals of 90 species captured on both mainland and in: hannel island sites. Island locafion captures totaled 595 individuals of 47 species )etween 2002 and 2004. Islands formerly were considered inconsequential for coraging and nesting of passerines. My study substantiated passerine use of Islands and provided a rationale for additional consideration of islands for migration and nesting management. Assemblages of bird species …

Intraspecific And Interspecific Territoriality In Microtus Ochrogaster And M. Pennsylvanicus, David J. Tazik, Lowell L. Getz

The Prairie Naturalist

Adult female Microtus ochrogaster and M. pennsylvanicus displayed interspecific territorial behavior in a bluegrass site in Illinois. We concluded that within a site, interspecific territorial behavior might be a factor in non-synchronous population fluctuations characteristic of the two species.

Partial Characterization Of Two Moderately Halophilic Bacteria From A Kansas Salt Marsh, Aileen M. Johnson, Lance R. Thurlow, Sam R. Zwenger, Eric T. Gillock

The Prairie Naturalist

Two bacterial species were isolated from a salt marsh located on privately owned land in Russell County, Kansas. Water samples from the saIt marsh were streaked for isolation on tryptic soy agar supplemented with 12 % NaCI. Visual scanning of the plates revealed two prominent colony types. The two colony types were subcultured repeatedly until axenic cultures were obtained. 80th of these organisms were shown to be moderately halophilic. The organisms were characterized partially by fatty acid methyl ester analysis, 16S rRNA sequencing, and scanning electron microscopy. These studies revealed that the bacteria previously were unreported members of genera Marinococcus …

The Prairie Naturalist, Volume 39, No.1, March 2007

The Prairie Naturalist

CONTENTS

MALLARD BROOD MOVEMENTS IN THE CANADIAN PRAIRIE PARKLANDS G. H. Raven, T. W. Arnold, D. W. Howerter, and L. M. Armstrong

WOODLAND BIRD USE OF IN-CHANNEL ISLANDS IN THE CENTRAL PLATTE RIVER, NEBRASKA, W. C. Scharf

PARTIAL CHARACTERIZATION OF TWO MODERATELY HALOPHILIC BACTERIA FROM A KANSAS SALT MARSH, A. M. Johnson, L. R. Thurlow, S. R. Zwenger, and E. T. Gillock

INTRASPECIFIC AND INTERSPECIFIC TERRITORIALITY IN MICROTUS OCHROGASTER AND M. PENNSYLVANICUS, D. J. Tazik and L. L. Getz

VEGETATIVE CHARACTERISTICS OF PRONGHORN BED SITES IN WIND CAVE NATIONAL PARK, SOUTH DAKOTA, C. N. Jacques, J. A. Jenks, J. D. …

Vegetative Characteristics Of Pronghorn Bed Sites In Wind Cave National Park, South Dakota, Christopher N. Jacques, Jonathan A. Jenks, Jaret D. Sievers, Daniel E. Roddy

The Prairie Naturalist

Much of the previous literature on pronghorn (Antilocapra americana) fawns has focused on fawn mortality (Beale 1978, Barrett 1984, Gregg et al. 2001) and social behavior (Kitchen 1974, Autenrieth and Fichter 1975, Bromley 1977). Selection of bed sites by pronghorn fawns is a major factor affecting fawn survival (Bromley 1978, Barrett 1981, O'Gara et al. 1986, VanSchmus 1990) because adequate cover is a crucial component of fawn bed site selection (Autenrieth 1984). Alldredge et al. (1991) reported that fawns selected dense shrub cover but avoided the most-dense cover in sagebrush-steppe communities in southcentral Wyoming while Tucker and Gamer …

Induced Nested Galactic Bars Inside Assembling Dark Matter Halos, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula

Department of Physics and Astronomy Faculty Publications

We investigate the formation and evolution of nested bar systems in disk galaxies in a cosmological setting by following the development of an isolated dark matter (DM) and baryon density perturbation. The disks form within the assembling triaxial DM halos, and the feedback from the stellar evolution is accounted for in terms of supernovae and OB stellar winds. Focusing on a representative model, we show the formation of an oval disk and of a first generation of nested bars with characteristic subkiloparsec sizes and a few kiloparsec sizes. The system evolves through successive dynamical couplings and decouplings, forcing the gas …

Privacy-Preserving Credentials Upon Trusted Computing Augmented Servers, Yanjiang Yang, Robert H. Deng, Feng Bao

Research Collection School Of Computing and Information Systems

Credentials are an indispensable means for service access control in electronic commerce. However, regular credentials such as X.509 certificates and SPKI/SDSI certificates do not address user privacy at all, while anonymous credentials that protect user privacy are complex and have compatibility problems with existing PKIs. In this paper we propose privacy-preserving credentials, a concept between regular credentials and anonymous credentials. The privacy-preserving credentials enjoy the advantageous features of both regular credentials and anonymous credentials, and strike a balance between user anonymity and system complexity. We achieve this by employing computer servers equipped with TPMs (Trusted Platform Modules). We present a …

Sedimentology Of Acid Saline Lakes In Southern Western Australia: Newly Described Processes And Products Of An Extreme Environment, Kathleen Counter Benison, Brenda Beitler Bowen, Francisca Oboh-Ikuenobe, Elliot A. Jagniecki, Deidre A. Laclair, Stacy L. Story, Melanie R. Mormile, Boyoung Hong

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Naturally acid saline systems with pH values between 1.7 and 4 are common on the Yilgarn Craton of southern Western Australia. a combination of physical and chemical processes here yield a previously undescribed type of modern sedimentary environment. Flooding, evapoconcentration, desiccation, and eolian transport at the surface, as well as influx of acid saline groundwaters, strongly influence these lakes. Halite, gypsum, kaolinite, and iron oxides precipitate from acid hypersaline lake waters. Shallow acid saline groundwaters affect the sediments of the lakes and associated mudflats, sandflats, channels, and dunes by precipitating early diagenetic halite, gypsum, iron oxides, clays, jarosite, and alunite. …

Wmi Outdoor News Bulletin * March 2007, Volume 61, No. 3

Wildlife Management Institute Outdoor News Bulletin

Contents:

• Chronic Wasting Disease update

• Conservationists irked by USDA promotion of amber waves of gas at CRP expense

• Tennessee provides leadership for native grass restoration in the Southeast

• National Wildlife Refuges to suffer large cutbacks in staff

• Rio Grande Bosque legislation introduced

• Worth reading: Fly-fishing for Sharks: An American Journey

The Effect Of Si Doping On The Electrical Properties Of B12as2 Thin Films On (0001) 6h-Sic Substrates, Zhou Xu, J. H. Edgar, David C. Look, S. Baumann, R. J. Bleiler, S. H. Wang, S. E. Mohney

Physics Faculty Publications

The ability to control the resistivity of the wide band gap semiconductor B₁₂As₂ by doping with silicon was verified. The electrical properties of nominally undoped and Si-doped rhombohedral B₁₂As₂ thin films on semi-insulating 6H-SiC (0001) substrates prepared by chemical vapor deposition were subjected to Hall effect measurements. Varying the Si concentration in the B₁₂As₂ thin films from 7×10¹⁸ to 7×10²¹ at./cm³ (as measured by secondary ion mass spectrometry) decreased the resistivities of the p-type B₁₂As₂ films from 2×10⁵ to 10 Ω …

Kings River Quality Assurance Project Final Report, Marc Nelson, Sam Davis

Technical Reports

The Kings River Watershed Partnership non-profit citizens group formed to take local control over water quality issues in the Kings River watershed in Arkansas. One of the first items the group addressed was water quality monitoring of the Kings River and Osage Creek. To this end they formed a water quality monitoring committee that was charged with the development of a water quality monitoring plan. The objectives of the plan they developed are: 1) to characterize both spatial and temporal variability in water quality parameters throughout the watershed during each year, 2) to utilize volunteers to monitor the water quality, …

Investigating Coastal Processes And Nitrate Levels In The Elkhorn Slough Using Real-Time Data, Lisa G. Adams, George I. Matsumoto

Faculty Articles

The primary objective of this activity is to predict how coastal processes, such as tides, affect salinity, temperature, and nitrate levels in a type of estuary, called a slough. Real-time data from the Elkhorn Slough National Estuarine Research Reserve in Monterey, California, will be used to test predictions. In addition to collecting, graphing, and interpreting real-time data, students will learn how nitrates enter the estuary, and they will gain a better understanding of the interconnectedness of all bodies of water, especially estuaries.

Control Of Hiv Through The Inhibition Of Hiv-1 Integrase: A Medicinal Chemistry Perspective, Christopher Gordon, R. Griffith, Paul A. Keller

Faculty of Science - Papers (Archive)

This article reviews the current status of classes of HIV-1 integrase enzyme inhibitors. These classes include peptide-based inhibitors, natural products, polyhydroxylated aromatics, diketo acids, naphthyridines, and sulfonated compounds including sulfonic acids. Discussions of structure activity relationships are presented and include the current overview of the structure-based model, suitable for the further design and development. To date, the advances in the medicinal chemistry of HIV-1 integrase inhibitors have relied mostly on ligand-based designs leading to most displaying similar binding interactions within the active site or at the dimer interface. This paves the way for single enzyme mutations rendering entire compound classes …

Sulfur Geochemistry And Diagenesis In A Gas Hydrate Terrane, Cascadia Margin, Offshore Oregon: Role Of Anaerobic Methane Oxidation, David Deigert, Walter S. Borowski

EKU Faculty and Staff Scholarship

We present sulfide mineral data from south Hydrate Ridge located in a gas hydrate terrane, offshore Oregon. Sulfide sulfur concentration and the isotopic composition of sulfur (d³⁴S) in authigenic sulfide minerals are analyzed from sediment samples collected on Ocean Drilling Project (ODP) Leg 204. Shallow sediment samples (<25 >mbsf) assess the relative importance of anaerobic methane oxidation (AMO) as a biogeochemical process, both here and at the Blake Ridge, another well known gas hydrate terrane offshore southeastern United States. Deep samples (>25 mbsf) are used to evaluate sulfur diagenesis and its controls from early Pleistocene to the …

Graphical And Bayesian Analysis Of Unbalanced Patient Management Data, Emily Stewart Righter

Theses and Dissertations

The International Normalizing Ratio (INR) measures the speed at which blood clots. Healthy people have an INR of about one. Some people are at greater risk of blood clots and their physician prescribes a target INR range, generally 2-3. The farther a patient is above or below their prescribed range, the more dangerous their situation. A variety of point-of-care (POC) devices has been developed to monitor patients. The purpose of this research was to develop innovative graphics to help describe a highly unbalanced dataset and to carry out Bayesian analyses to determine which of five devices best manages patients. An …