Physical Sciences and Mathematics Commons^™

Spectroscopy And Carrier Dynamics In Cdse Self-Assembled Quantum Dots Embedded In Znxcdymg1−X−Yse, G. Comanescu, W. B. Wang, S. Gundry, B. Das, R. R. Alfano, M. N. Perez-Paz, M. C. Tamargo, M. Muñoz, I. Popov, L. L. Isaacs

Physics Publications

Time-resolved and steady-state photoluminescence,reflectivity, and absorption experiments were performed on CdSequantum dots in ZnxCdyMg1−x−ySe barriers. Studies of the capture times of the photoexcited carriers into the quantum dots and of electron-hole recombination times inside the dots were performed. Photoluminescence rise time yielded capture times from 20 ps to 30 ps. All samples exhibit fast and slow photoluminescence decays, consistent with observing two independent but energetically overlapping decays. The faster relaxation times for the sample emitting in the blue range is 90 ps, whereas for the two samples emitting in the green it is 345 ps and 480 ps. The slower …

Magnetic Coupling Between Cr Atoms Doped At Bulk And Surface Sites Of Zno, Q. Wang, Q. Sun, Puru Jena, Y. Kawazoe

Physics Publications

Contrary to theoretical prediction that Cr-doped bulk ZnO is ferromagnetic, recent experiments on Cr-doped ZnOthin film reveal the coupling to be antiferromagnetic. Using first-principles calculations based on gradient corrected density functional theory, we show that a possible origin of this disagreement may be associated with the site preference of Cr. In bulk, when Cr substitutes Zn,bond contraction occurs and Cr atoms prefer to cluster around O atoms. The ferromagnetic coupling among Cr atoms is driven by Cr 3d and O 2p exchange interactions as in Cr2O cluster. However, when Cr atoms replace Zn on the surface, due to the different …

First-Principles Study Of The Onset Of Noncollinearity In Mnn Clusters: Magnetic Arrangements In Mn5 And Mn6, T. Morisato, Shiv N. Khanna, Y. Kawazoe

Physics Publications

First-principles theoretical investigations of the noncollinearity of atomic spin moments in manganese clusters have been carried out within a gradient-corrected density-functional approach. Our studies on Mn5 and Mn6 include investigation of both collinear and noncollinear arrangements. It is shown that while the atomic structure of the ground state of Mn5 is a triangular bipyramid, the collinear and noncollinear arrangements have comparable energies and hence are degenerate. For Mn6, while the ground state has a square bipyramid arrangement, the noncollinear configuration is most stable making it the smallest cluster to feature a noncollinear ground state. The results are discussed in view …

Fy2005 Annual Report Of The Water Quality Monitoring Project For The Water Quality Protection Program Of The Florida Keys National Marine Sanctuary, Joseph N. Boyer, Henry O. Briceño

SERC Research Reports

No abstract provided.

Weak Factorizations, Fractions And Homotopies, Alexander Kurz, Jiří Rosický

Engineering Faculty Articles and Research

We show that the homotopy category can be assigned to any category equipped with a weak factorization system. A classical example of this construction is the stable category of modules. We discuss a connection with the open map approach to bisimulations proposed by Joyal, Nielsen and Winskel.

Static Source Code Weaving : Overcoming The Challenges Of Aspect-Oriented Programming, Stephen Malone

Theses

Aspect-Oriented Programming (AOP) is a relatively new programming paradigm, which promises to allow developers to express cross-cutting concerns independently of their application to the primary core concerns of a system. This promises to allow developers the freedom to reason about both the cross-cutting concerns of a system as well as its primary concerns. In allowing for the expression of cross-cutting concerns AOP is extremely powerful; significant benefits have been found such as the ability to reason about cross-cutting concerns, and in some cases dramatic reductions in the number of lines of code required to implement crosscutting behaviour. These benefits however …

Multivariate Analysis Of Prokaryotic Amino Acid Usage Bias: A Computational Method For Understanding Protein Building Block Selection In Primitive Organisms, Douglas Whitmore Raiford Iii

Browse all Theses and Dissertations

Organisms expend a significant fraction of their overall energy budget in the creation of proteins, particularly for those that are produced in large quantities. Recent research has demonstrated that genes encoding these proteins are shaped by natural selection to produce the proteins with low cost building blocks (amino acids) whenever possible. The negative correlation between protein production rate and their energetic costs has been established for two bacterial genomes: Escherichia coli and Bacillus subtilis. This thesis provides scientific validation of this theory by automating the analysis and extending the research to additional genomes. Investigations into building block selection are highly …

Cluster Issue On Microplasmas, Kurt H. Becker, J. Gary Eden, Karl H. Schoenbach

Bioelectrics Publications

Atmospheric-pressure diffuse discharge plasmas are susceptible to instabilities and, in particular, to arcing (the glow-to-arc transition). Some of the most promising approaches to ‘stabilizing’ atmospheric-pressure plasmas are based on the recognition that arc formation can be avoided when the plasmas are generated and maintained in spatially constricted geometries with dimensions from tens to hundreds of microns. Known as microplasmas or microdischarges, these weakly-ionized discharges represent a new and fascinating realm of plasma science in which several scientific issues, such as the potential breakdown of pd scaling and the role of boundary-based phenomena, come to the fore. In contrast to ‘macroplasmas’ …

Iowa Academy Of Science 117th Annual Meeting [2005]: Advance Program, Iowa Academy Of Science

Iowa Academy of Science Documents

Contains information about the schedule and presentations for the 2005 annual meeting of the Iowa Academy of Science.

117th Annual Meeting Of The Iowa Academy Of Science [Program, 2005], Iowa Academy Of Science

Iowa Academy of Science Documents

Contents:

Program Summary --- 4
General Session Presentations --- 6
Symposia Programs --- 9
General Poster Session Program --- 10
Cellular, Molecular and Microbiology Special Poster Session Program --- 12
Section Meeting Programs (Alphabetical by Section) --- 13
2005 IAS Awards and Recognition --- 18
Geology Field Trip Details --- 19
Section Meeting Abstracts (by Section) --- 20
Symposia Abstracts --- 64
Author Index --- 68

First Record Of An Adult Male Evening Bat From Kansas, Clay R. Davis, Justin G. Boyles

The Prairie Naturalist

The evening bat (Nycticeius humeralis) occurs throughout the eastern and southeastern United States and into extreme northeastern Mexico, approximately 42° to 18° N latitude (Watkins and Shump 1981). Although records of females are common, records of adult male evening bats are rare in the northern portion of the species range (Watkins 1969, Watkins 1972). Jones et al. (1967) suggested that adult males might not accompany females to at least some parts of the parturient range. As part of a larger study (Davis 2003) we surveyed bats on Fort Leavenworth Military Reservation (FLMR), Leavenworth County, Kansas in July 2002 …

Analyses Of Natural Gases, 2002–2004, B. D. Gage, D. L. Driskill

United States Bureau of Land Management: Staff Publications

Technical Note 418 contains analyses and related source data for 451 natural gas samples from 15 States. Of the total samples, 381 were collected during calendar years 2002 through 2004. The analyses were done using gas chromatography. None of the analyses have been published previously in other analyses reports. All samples were obtained and analyzed as part of the United States Department of the Interior’s Bureau of Land Management investigations of the occurrences of helium in natural gases of countries with free-market economies. The results of these investigations are published periodically to make the information available to members of the …

Microclimate Effects From Closing Abandoned Mines With Culvert Bat Gates, Robert H. King

United States Bureau of Land Management: Staff Publications

Numerous bat species, including some threatened species, inhabit thousands of abandoned mines across the United States. Some of their bat habitat has been lost as mines are closed to reduce hazards to the public. Bat gates have been used to close some mines because they restrict public access while still allowing the bats to fly in and out. However, they are not appropriate for mines with trench portals. The Bureau of Land Management (BLM) proposed using culverts in the trenches and closing the culverts with bat gates. BLM worked with the Colorado School of Mines (CSM) to study the effects …

Getting Organized At The Nanoscale With Thermotropic Liquid Crystal Solvents, David L. Patrick, F. Scott Wilkinson, Tiffany L. Fegurgur

Chemistry Faculty and Staff Publications

This paper summarizes recent progress toward an emerging, unconventional application of thermotropic liquid crystals (LCs) - their use as solvents for controlling the assembly of non-LC nanoscale building blocks. LCs offer a number of potential advantages compared to conventional isotropic solvents, including the ability to influence building block orientation and other structural properties. Strategies are reviewed for the exploitation of LC media to engineer order in a range of systems, including oriented organic monolayers, chiral films, and nanometer-scale particles.

Flocks And Formations, J. J. P. Veerman, Gerardo Lafferriere, John S. Caughman Iv, A. Williams

Mathematics and Statistics Faculty Publications and Presentations

Given a large number (the “flock”) of moving physical objects, we investigate physically reasonable mechanisms of influencing their orbits in such a way that they move along a prescribed course and in a prescribed and fixed configuration (or “in formation”). Each agent is programmed to see the position and velocity of a certain number of others. This flow of information from one agent to another defines a fixed directed (loopless) graph in which the agents are represented by the vertices. This graph is called the communication graph. To be able to fly in formation, an agent tries to match the …

The Correlation Between Internal & External Markers For Abdominal Tumors: Implications For Respiratory Gating, David P. Gierga, Johanna Brewer, Gregory C. Sharp, Margrit Betke, Christopher G. Willett, George T.Y. Chen

Computer Science: Faculty Publications

Purpose: The correlation of the respiratory motion of external patient markers and abdominal tumors was examined. Data of this type are important for image-guided therapy techniques, such as respiratory gating, that monitor the movement of external fiducials.

Methods and Materials: Fluoroscopy sessions for 4 patients with internal, radiopaque tumor fiducial clips were analyzed by computer vision techniques. The motion of the internal clips and the external markers placed on the patient’s abdominal skin surface were quantified and correlated.

Results: In general, the motion of the tumor and external markers were well correlated. The maximum amount of peak-to-peak craniocaudal tumor motion …

Finding And Maintaining Rigid Components, Audrey Lee, Ileana Streinu, Louis Theran

Computer Science: Faculty Publications

We give the first complete analysis that the complexity of finding and maintaining rigid components of planar bar-and-joint frameworks and arbitrary d-dimensional body-and-bar frameworks, using a family of algorithms called pebble games, is O(n2). To this end, we intro- duce a new data structure problem called union pair- find, which maintains disjoint edge sets and supports pair-find queries of whether two vertices are spanned by a set. We present solutions that apply to generalizations of the pebble game algorithms, beyond the original rigidity motivation.

Pseudo-Triangulations, Rigidity And Motion Planning, Ileana Streinu

Computer Science: Faculty Publications

This paper proposes a combinatorial approach to planning non-colliding trajectories for a polygonal bar-and-joint framework with n vertices. It is based on a new class of simple motions induced by expansive one-degree-of-freedom mechanisms, which guarantee noncollisions by moving all points away from each other. Their combinatorial structure is captured by pointed pseudo-triangulations, a class of embedded planar graphs for which we give several equivalent characterizations and exhibit rich rigidity theoretic properties. The main application is an efficient algorithm for the Carpenter's Rule Problem: convexify a simple bar-and-joint planar polygonal linkage using only non-self-intersecting planar motions. A step of the algorithm …

A Dictionary Construction Technique For Code Compression Systems With Echo Instructions, Philip Brisk, Jamie Macbeth, Ani Nahapetian, Majid Sarrafzadeh

Computer Science: Faculty Publications

No abstract provided.

Computing Rigid Components Of Pseudo-Triangulation Mechanisms In Linear Time, Jack Snoeyink, Ileana Streinu

Computer Science: Faculty Publications

We investigate the problem of detecting rigid components (maximal Laman subgraphs) in a pseudotriangulation mechanism and in arbitrary pointed planar frameworks.F or general Laman graphs with some missing edges, it is known that rigid components can be computed in O(n2) time.Here we make substantial use of the special geometry of pointed pseudo-triangulation mechanisms to achieve linear time. The main application is a more robust implementation and a substantial reduction in numerical computations for the solution to the Carpenter's Rule problem given by the second author.

The Forest Service's Quest For Power And Money: Implications Of A Budget-Maximizing Agency, Allison M. Stewart

Honors Theses

The Forest Service manages land for a diverse array of purposes under the Multiple Use Doctrine. Many of these uses are incompatible and lead to conflict The goal of my research is to explain what guides the Forest Service's management decisions, since this is critical to understanding how conflicts are resolved, .and uncover alternative approaches that better protect the environment.

In this paper, I present a brief history of the Forest Service's management over the past century. Particular attention is given to explaining trends in timber and recreation management. Following the historical presentation, I attempt to identify a set of …

Sedimentological Characteristics And Internal Architecture Of Two Overwash Fans From Hurricanes Ivan And Jeanne, Mark H. Horwitz, Ping Wang

Geology Faculty Publications

Extensive overwash occurred along the Florida coast during the passage of four strong hurricanes in 2004, providing an excellent opportunity to study the spatial patterns and sedimentary architecture of washover deposits. Detailed 3D sedimentological characteristics of two of the overwash fans were studied through coring, trenching, and ground penetration radar surveys. The first washover-fan complex, deposited by hurricanes Frances and Jeanne is located on the Atlantic facing Hutchinson Island in southeastern Florida. The second fan, deposited by hurricane Ivan is located on the Gulf-facing Santa Rosa Island in northwestern Florida. Subsurface imaging using a 250 MHz Ground penetrating radar profiling …

Cross-Formational Flow, Diffluence And Transfluence Observed In St. Beatus Cave And Sieben Hengste (Switzerland), Philipp Häuselmann

International Journal of Speleology

Observations in St. Beatus Cave and neighbouring caves revealed complex water flowpaths that can be used for explaining the behaviour of tracing experiments. The observations prove that even in vadose conditions, cross-formational flow, diffluences and transfluences are a quite common feature. Therefore, also the vadose karst has a very complex organisation.

Agraphorura Calvoi N. Sp. From Venezuelan Caves (Collembola: Onychiuridae), Javier I. Arbea

International Journal of Speleology

A new species of Agraphorura (Collembola: Poduromorpha: Onychiuridae) from caves in the Nort-West of Venezuela is described. A. calvoi n. sp. can be distinguished from its congeners by the following combination of characters: antennal organ III with four papillae, 32/133/33343 dorsal pseudocellar formula, 3/000/0112 ventral pseudocellar, subcoxae each with two pseudocelli, postantennal organ with 7-9 vesicles, unguiculus with a basal lamella, tibiotarsi I-III with 19,19,18 setae (distal whorl of 9 setae). A table with the differential characters, as well as an identifi cation key for all of the known species of Agraphorura are provided.

Absorption And Backscattering In The Beaufort And Chukchi Seas, Jian Wang, Glenn F. Cota, David A. Ruble

CCPO Publications

Bio-optical observations were made during August 2000 in the Beaufort and Chukchi Seas. Chlorophyll a concentration (Chl) ranged from 0.068 to 18.5 mg chl m^-3. Both total particulate and phytoplankton absorption at 443 nm were closely correlated with chlorophyll concentration. Linear spectral relationships were observed for phytoplankton absorption. The chlorophyll-specific absorption of phytoplankton at 443 nm was nearly constant at 0.013 m² (mg chl)^-1, but particulate absorption due to nonpigmented particulates at 443 nm was highly variable. There was no strong correlation between chlorophyll concentration and absorption by soluble materials or nonpigmented particulates. Absorption, scattering, …

Seasonal Variability Of Near-Surface Hydrography And Frontal Features In The Northern Gulf Of Alaska And Prince William Sound, Stephen R. Okkonen, David L. Cutchin, Thomas Royer

CCPO Publications

The meridional structure and seasonal cycles of near-surface hydrography and frontal features in the northern Gulf of Alaska and Prince William Sound are described from high-resolution measurements of near-surface temperature and salinity acquired by a vessel-mounted thermosalinograph. Near-surface temperature exhibits a well-defined seasonal cycle with little variation between basin and shelf waters. Near-surface salinity exhibits a well-defined seasonal cycle that is confined largely to the shelf waters reflecting the influence of coastal freshwater inputs. Prominent near-surface fronts at the shelf break, at the entrance to Prince William Sound, and in northern Prince William Sound intensify and weaken following the seasonal …

Circulation, Mixing And The Distribution Of Remineralized Nutrients, Larry P. Atkinson, John Huthnance, Jose L. Blanco

CCPO Publications

No abstract provided.

The Establishment, Expansion And Ecosystem Effects Of Phragmites Australis, An Invasive Species In Coastal Louisiana, Lee Ellis Stanton

LSU Doctoral Dissertations

As biological invasions have become a common phenomenon throughout the world, ecologists have intensified efforts to understand why natural communities are susceptible to invasion. Invading species can cause shifts in community structure that result in irreversible changes to ecosystem function. Phragmites australis has rapidly spread in North American coastal wetlands during the past 50 years and has become a dominant feature in Northern Gulf of Mexico brackish marshes. The rate at which Phragmites is spreading or the mechanisms controlling its establishment in these marshes is unknown. My research objectives were to: (1) determine the spatial and temporal patterns of Phragmites …

Five-Year Review Of Executive Order 13112 On Invasive Species, The National Invasive Species Council (Nisc)

All U.S. Government Documents (Utah Regional Depository)

No abstract provided.

Seepage Study Of Mcleod Creek And East Canyon Creek Near Park City, Summit County, Utah, 2004, C. D. Wilkowske, U.S. Geological Survey, Snyderville Basin Water Reclamation District, U.S. Department Of The Interior

All U.S. Government Documents (Utah Regional Depository)

Seepage investigations on McLeod Creek downstream of U.S. Geological Survey streamflow-gaging station McLeod Creek near Park City, Utah, and its confluence with Kimball Creek during the summer of 2004 indicate that this section of the creek is a gaining reach. The total seepage gains ranged from 1.8 to 2.7 cubic feet per second, or a 32 to 55 percent gain. The apparent average total seepage gain was 2.2 cubic feet per second, or an average 42 percent gain. Seepage investigations from the U.S. Geological Survey streamflow-gaging station at East Canyon Creek below I-80 Rest Stop near Park City, Utah, to …