Physical Sciences and Mathematics Commons^™

Sige/Si Thz Laser Based On Transitions Between Inverted Mass Light-Hole And Heavy-Hole Subbands, L. Friedman, Greg Sun, Richard A. Soref

Physics Faculty Publications

We have investigated a SiGe/Si quantum-well laser based on transitions between the light-hole and heavy-hole subbands. The lasing occurs in the region of k space where the dispersion of ground-state light-hole subband is so nonparabolic that its effective mass is inverted. This kind of lasing mechanism makes total population inversion between the two subbands unnecessary. The laser structure can be electrically pumped through tunneling in a quantum cascade scheme. Optical gain as high as 172/cm at the wavelength of 50 μm can be achieved at the temperature of liquid nitrogen, even when the population of the upper laser subband is …

Routing Algorithms For Channels, Switchboxes And Mcm's In Vlsi Layout Design., Sandip Das Dr.

Doctoral Theses

The term Very Large Scale Integration (VLSI) reflects the capability of semi- conductor industry to fabricate a complex electronic circuit consisting of millions of components on a single silicon substrate. The growth of semiconductor technol- ogy in recent years has been described by "Moore's law", enunciated in the late 1960s, which projected quadrupling of components in a chip in every three to four years. Several factors contributed to this tremendous growth : (i) reduction of line width of the basic device and interconnection wires due to the development of high- resolution lithographic techniques and improved processing capabilities, (ii) increase in …

The Hanle Effect As A Diagnostic Of Magnetic Fields In Stellar Envelopes Iii. Including The Finite Star Depolarization Effect., R. Ignace

Richard Ignace

The Hanle effect is a relatively new magnetic diagnostic in stellar astrophysics. Although a substantial literature exists for applications of the Hanle effect in solar studies, the Hanle effect is only a fledgling subject in stellar astrophysics, with previous work focusing on simplistic cases to isolate the magnetic effects on polarized resonance scattering line profiles. In particular, applications to stars have treated the star as a point source of illumination. This paper carries the work forward by considering the consequences of finite stellar size for the line polarization. An approach based on intensity moments is derived. For optically thin line …

Monitoring Changes In Feral Swine Abundance And Spatial Distribution, Richard M. Engeman, Bernice Constantin, Mark Nelson, John Woolard, Jean Bourassa

United States Department of Agriculture Wildlife Services: Staff Publications

Swine (Sus scrofa) have been introduced in many places throughout the world, and in many places they adversely affect the environment, economically impact agriculture, and/or harbor diseases transmittable to domestic livestock or humans. An easily applied method to assess their abundance is an important need for their management. To monitor efficacy of a swine control program in Florida, data from passive tracking plots provide an index of feral swine abundance. The same track data coupled with plot locations to numerically describe the spatial pattern of swine activity gave an index of pervasiveness, and a simple rate of interception …

A Review Of The Hazards And Mitigation For Airstrikes From Canada Geese In The Anchorage, Alaska Bowl, Darryl L. York, Richard M. Engeman, John L. Cummings, Corey L. Rossi, David R. Sinnett

United States Department of Agriculture Wildlife Services: Staff Publications

Bird strikes to aircraft are a globally pervasive safety and economic concern. In particular, the Anchorage, Alaska area holds substantial risk for destructive collisions between birds and aircraft. An international airport, a municipal airport, a seaplane base, and a U.S. Air Force base are situated throughout the area. Anchorage also has a burgeoning population of Canada geese (Branta canadensis parvipes), one of the species identified as posing the greatest airstrike hazards. A variety of methods are applied and a variety of research has been conducted to reduce the potential for airstrikes with geese around Anchorage.We review the nature …

Understanding Vole Problems In Direct Seeding — Strategies For Management, Gary W. Witmer, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Crop fields can provide habitat to a variety of wildlife and crop damage can result (Wywialowski 1996, 1998; Conover 1998). Among the vertebrates, damage can occur from numerous species of birds and mammals. Worldwide concern, however, has focused on rodents and a large number of species cause substantial agricultural losses each year (Witmer et al. 1995). After the advent of effective herbicides and "clean farming" practices in North America, however, many rodent problems became insignificant (Hines and Hygnstrom 2000). This is, in large part, because the fields were plowed each year, disrupting burrows and removing ground cover. The fields often …

Progress On Cattail Management To Reduce Blackbird Damage To Sunflower, H. Jeffrey Homan, George M. Linz, Ryan L. Wimberly, Linda B. Penry

United States Department of Agriculture Wildlife Services: Staff Publications

In 1989, the USDA began experimenting with cattail management to reduce sunflower damage caused by blackbirds. Dense stands of cattail, which often hold large numbers of blackbirds in late summer and early fall, were thinned with glyphosate-based herbicide. Based on promising results from initial research, a statewide cattail management program was started by the USDA in 1991.

Has An Integrated Pest Management Approach Reduced Blackbird Damage To Sunflower?, George M. Linz, Brian D. Peer, H. Jeffrey Homan, Ryan L. Wimberly, David L. Bergman, William J. Bleier, Linda B. Penry

United States Department of Agriculture Wildlife Services: Staff Publications

Since the mid- 1970s many new and modified damage abatement methods have been used to reduce blackbird damage to ripening sunflower in the northern Great Plains. To assess the overall impact of these techniques, we analyzed the dynamic relationship between breeding blackbird densities and sunflower damage. Breeding density estimates were made at both the regional and county levels, whereas, sunflower damage estimates were made at the county level only. Periodic regional estimates of breeding densities between 1967 and 1998 for red-winged blackbirds (Agelaius phoeniceus), common grackles (Quiscalus quiscula), and yellow-headed blackbirds (Xanthocephalus xanthocephalus) showed …

Habitat Characteristics Around Fall Blackbird Roosts, Mark W. Lutman, George M. Linz, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

In the fall, blackbirds form large flocks and roost overnight in cattail marshes. These blackbirds cause millions of dollars in damage to ripening sunflower fields in North Dakota, South Dakota, and Minnesota. By knowing the habitat characteristics around fall blackbird roosts sites, management officials may be able to predict future roost locations and then implement control techniques to help reduce blackbird damage to sunflower fields. We present data on the available habitat around blackbird roosts to determine if there is a relationship between the habitat and fall roost sites.

Impact Of Blackbird Damage To Sunflower Bioenergetic And Economic Models, Brian D. Peer, H. Jeffrey Homan, George M. Linz, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

We constructed bioenergetic models to assess the economic impact on sunflower production horn a regional population of blackbirds (Icteridae) consisting of three species: red-winged blackbirds (Agelaius phoeniceus), common grackles (Quiscalus quiscula), and yellow-headed blackbirds (Xanthocephalus xanthocephalus). Values generated from the bioenergetic models were used to perform a cost-benefit analysis to determine efficacy of a proposed avicide baiting program to manage red-winged blackbirds residing in the Central Lowlands and Northern Great Plains regions of North America. The bioenergetic model included metabolic rates, caloric value and moisture content of achenes, and percentage of sunflower in the …

Local Removal Of Red-Winged Blackbirds: Potential For Blackbird Management?, Richard . S. Sawin, George M. Linz, William J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

Fall flocks of red-winged blackbirds (Agelaius phoeniceus) are well known for their ability to damage crops such as sunflower (Linz and Hanzel 1997). In response, wildlife managers have considered local population reduction as a strategy for reducing blackbird damage. Male red-winged blackbirds are logistically easier to remove than females because of their conspicuous behavior. However, they exhibit a polygynous breeding system, and male removals may be ineffective if a large population of floaters exists to replace removed birds. We present data from an experimental removal project in two North Dakota townships and discuss the implications for local blackbird …

Avian Use Of Ripening Sunflower Fields, Dionn Schaaf, George M. Linz, William J. Bleier, H. Jeffrey Homan

United States Department of Agriculture Wildlife Services: Staff Publications

In the United States, more than 90% of cultivated sunflower is raised in the northern Great Plains. Cattail marshes in this area provide nesting and roosting sites for red-winged blackbirds, yellow-headed blackbirds, and common grackles. North Dakota's breeding blackbird population was estimated at more than 2.3 million pairs in 1990. Sunflower has become an important part of blackbirds' diet from July-October . In 1999 and 2000, research was conducted on the use of avicide-treated (DRC- 1339, 3-chloro-p-toluidine hydrochloride) rice baits for managing blackbird damage in problem areas. DRC- 1339 was chosen for this purpose because of its high …

Understanding Vole Problems In Direct Seeding-Strategies For Management, Gary W. Witmer, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Crop fields can provide habitat to a variety of wildlife and crop damage can result (Wywialowski 1996,1998; Conover 1998). Among the vertebrates, damage can occur from numerous species of birds and mammals. Worldwide concern, however, has focused on rodents and a large number of species cause substantial agriculture losses each year (Witmer et al, 1995). After the advent of effective herbicides and "clean farming" practices in North America, however, many rodent problems became insignificant (Hines and Hygnstrom 2000). This is, in large part, because the fields were plowed each year, disrupting burrows and removing ground cover. The fields often lay …

Process For Immobilizing Waste Using Bagasse (Us Patent 6174275), Michael A. Janusa

Faculty Publications

No abstract provided.

Semiclassical Application Of The Mo”Ller Operators In Reactive Scattering, Sophya Garashchuk, John C. Light

Faculty Publications

Mo\ller operators in the formulation of reaction probabilities in terms of wave packet correlation functions allow us to define the wave packets in the interaction region rather than in the asymptotic region of the potential surface. We combine Mo\ller operators with the semiclassical propagator of Herman and Kluk. This does not involve further approximations and can be used with any initial value representation (IVR) semiclassical propagator. Time propagation in asymptotic regions of the potential due to Mo\ller operators reduces the oscillations of the propagator integrand and improves convergence of the results with respect to the number of trajectories. The effectiveness …

An Approach For Clarification Of The Mechanism Of Inactivation Of Ribonucleotide Reductases With 3'<¹⁷O>-Labeled 2'-Azido-2'-Deoxynucleotides, Saiful Mahmud Chowdhury

FIU Electronic Theses and Dissertations

Inactivation of ribonucleotide reductases by 2'-azido-2'-deoxynucleotides is accompanied by appearance of new EPR signals for a nitrogen-centered radical. The structure of this elusive nitrogen-centered radical has been studied extensively and shown to be derived from azide moiety. Synthesis of 3'[¹⁷ O]-labeled 2'-azido-2'-deoxyuridine-5'- diphosphate was targeted in this research. Such a labeled analogue should perturb the EPR spectrum in predictable fashion, and the hyperfine interaction between the free electron and the ¹⁷O nucleus should allow the choice between the recently proposed structures of this elusive radical (Van Der Donk, W. A. et al. J Am. Chem. Soc. 1995 …

Coyote Responses To Changing Jackrabbit Abundance Affect Sheep Predation, L. Charles Stoddart, Richard E. Griffiths, Frederick F. Knowlton

United States Department of Agriculture Wildlife Services: Staff Publications

Domestic sheep ranchers generally perceive abundances of natural prey and coyotes (Canis latrans) as important factors affecting coyote predation rates on sheep. To determine the effect of a changing natural prey base on coyote predation rates, we estimated coyote density and predation rates on ewes and lambs during part of 1 cycle of black-tailed jackrabbit (Lepus californicus) abundance on a 2,300 km² area of the Idaho National Engineering Laboratory in south-central Idaho from 1979–1985. We used 100, 1.6-km scat collection lines and 80, 1.6-km flushing transects to assess coyote and jackrabbit densities, respectively. Ewe and …

Tectorna: Modular Assembly Units For The Construction Of Rna Nano-Objects, Neocles B. Leontis, Luc Jaeger, Eric Westhof

Chemistry Faculty Publications

Structural information on complex biological RNA molecules can be exploited to design tectoRNAs or artificial modular RNA units that can self-assemble through tertiary interactions thereby forming nanoscale RNA objects. The selective interactions of hairpin tetraloops with their receptors can be used to mediate tectoRNA assembly. Here we report on the modulation of the specificity and the strength of tectoRNA assembly tin the nanomolar to micromolar range) by variation of the length of the RNA subunits, the nature of their interacting motifs and the degree of flexibility of linker regions incorporated into the molecules. The association is also dependent on the …

Quasistationary Stabilization Of The Decay Of A Weakly-Bound Level And Its Breakdown In A Strong Laser Field, N. L. Manakov, M. V. Frolov, Bogdan Borca, Anthony F. Starace

Anthony F. Starace Publications

Although it was pointed out about 10 years ago that an atomic decay rate might decrease as the intensity of a high-frequency laser field increases, there still does not exist any complete understanding of either the physical origin of this interesting nonlinear phenomenon or its dependence on the atomic and field parameters. Essentially, the problem consists in that the phenomenon requires a major modification of the standard picture of photoeffect in a strong laser field. In Reference #1 the origin of this stabilization is related to a particular distortion of an atomic potential by an intense monochromatic high-frequency field. This …

Anisotropy-Induced Polarization Effects In Harmonic Generation By An Absorptive Medium, Bogdan Borca, D. B. Milosević, Anthony F. Starace, A. V. Flegel, M. V. Frolov, N. L. Manakov

Anthony F. Starace Publications

High-order harmonic generation (HHG) has become a main topic of intense laser-atom physics. Both to understand the HHG process better and to enhance its use in applications, many studies have focused on the control of HHG. Among the most recent are those concerned with the polarization characteristics of the harmonics. Other studies have focused on the use of a strong static electric field to control the intensities and plateau structure of HHG. In this paper we present results of a general formulation of the problem of HHG in the case when the generating medium is anisotropic. Our specific results are …

High-Performance Liquid Chromatographic And Capillary Electrophoretic Enantioseparation Of Plant Growth Regulators And Related Indole Compounds Using Macrocyclic Antibiotics As Chiral Selectors, F. Hui, K. H. Ekborg-Ott, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Enantioseparation of plant growth regulators, such as 3-(3-indolyl)-butyric acid, abscisic acid and structurally related molecules including a variety of substituted tryptophan compounds, has been achieved by HPLC and/or CE. The covalently bonded macrocyclic antibiotics, teicoplanin, ristocetin A and vancomycin, were used as chiral stationary phases (CSPs) in HPLC. Most of the racemates were baseline resolved in the reversed-phase mode (EtOH-H2O) using the teicoplanin CSP. The chiral recognition mechanism is discussed in regard to the structure of the analytes. In CE, the three aforementioned macrocyclic antibiotics were used as chiral additives in a phosphate run buffer. The effect of pH and …

Jual Obat Aborsi Di Parigi 089666608881 Apotik Jual Obat Aborsi Parigi, Jual Obat Aborsi Parigi

JUAL OBAT ABORSI TUNTAS 089666608881 APOTIK JUAL OBAT PENGGGUGUR KANDUNGAN

Atomically Resolved Single-Walled Carbon Nanotube Intramolecular Junctions, Min Ouyang, Jin-Lin Huang, Chin Li Cheung, Charles M. Lieber

Barry Chin Li Cheung Publications

Intramolecular junctions in single-walled carbon nanotubes are potentially ideal structures for building robust, molecular-scale electronics but have only been studied theoretically at the atomic level. Scanning tunneling microscopy was used to determine the atomic structure and electronic properties of such junctions in single-walled nanotube samples. Metal-semiconductor junctions are found to exhibit an electronically sharp interface without localized junction states, whereas a more diffuse interface and low-energy states are found in metal-metal junctions. Tight-binding calculations for models based on observed atomic structures show good agreement with spectroscopy and provide insight into the topological defects forming intramolecular junctions. These studies have important …

Improvements In Turfgrass Color And Density Resulting From Comprehensive Soil Diagnostics, Matt Cordell, Jonathan Davis, David E. Longer

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

There are roughly 220 golf courses in Arkansas, and as many as 50% of these courses were constructed using common bermudagrass fairways. Although resilient, common bermudagrass loses density and quality over time. In this experiment physical and chemical properties of the soil were analyzed to determine the causes of decline in turf quality observed on several fairways of a local golf course. Once a particular fairway was selected for study and preliminary soil sampling conducted, GS+, a geostatistical computer program, was used to map the location of certain chemical deficiencies. A moderate to severe Mg deficiency was detected throughout the …

An Ellam Scheme For Multidimensional Advection-Reaction Equations And Its Optimal-Order Error Estimate, Hong Wang, Xiquan Shi, Richard E. Ewing

Faculty Publications

We present an Eulerian-Lagrangian localized adjoint method (ELLAM) scheme for initial-boundary value problems for advection-reaction partial differential equations in multiple space dimensions. The derived numerical scheme is not subject to the Courant-Friedrichs-Lewy condition and generates accurate numerical solutions even if large time steps are used. Moreover, the scheme naturally incorporates boundary conditions into its formulation without any artificial outflow boundary conditions needed, and it conserves mass. An optimal-order error estimate is proved for the scheme. Numerical experiments are performed to verify the theoretical estimate.

Simple Relationships For The Estimation Of Melting Temperatures Of Homologous Series, James S. Chickos, Gary Nichols

James Chickos

No abstract provided.

Topologically Pure Extensions, Peter Loth

Mathematics Faculty Publications

A proper short exact sequence 0→H →G→K→0 (*) in the category of locally compact abelian groups is said to be topologically pure if the induced sequence 0→nH→nG→nK→0 is proper short exact for all positive integers n. Some characterizations of topologically pure sequences in terms of direct decompositions, pure extensions and tensor products are established. A simple proof is given for a theorem on pure subgroups by Hartman and Hulanickl. Using topologically pure extensions, we characterize those splitting locally compact abelian groups whose torsion part is a direct sum of a compact …

Pitcher’S Thistle

National Invasive Species Council

What is the Pitcher’s thistle?

Scientific Name

Range

Appearance

Habitat

Reproduction

Why is the Pitcher’s thistle threatened?

Shoreline Development

Road Maintenance and Construction

Shoreline Recreation Activities

What is being done to prevent extinction of the Pitcher’s thistle?

Listing

Landowner Contacts

Project Planning

What can I do to help prevent the extinction of species?

Learn

Plant Natives

Conserve

Management Plan

National Invasive Species Council

Farmers, ranchers, scientists, State officials, and many others have urged the Federal Government to consider invasive species issues a priority and to develop a coordinated national effort to address the problem. In response, the President issued Executive Order 13112 on Invasive Species (Order) in February 1999. The Order established the National Invasive Species Council (Council), co-chaired by the Secretaries of Agriculture, Commerce, and the Interior; and includes the Secretaries of State, Treasury, Defense, and Transportation, and the Administrator of the Environmental Protection Agency. The Order directs the Council to form a non-Federal Invasive Species Advisory Committee (ISAC) to advise the …

Results Of Whole-Rock Organic Geochemical Analyses Of The Crp-3 Drillcore, Victoria Land Basin, Antarctica, Richard M. Kettler

Department of Earth and Atmospheric Sciences: Faculty Publications

Sediments and rocks recovered in CRP-3 coring operations contain minute amounts of organic matter (average 0.3% TOC). TOC contents and C:N ratios are zoned systematically: those rocks encountered at depths greater than 330 meters below sea floor (mbsf) contain less organic matter and have higher TOC:N ratios (after correcting for inorganic N) than do shallower rocks. The only two samples that have TOC values greater than 1% also contain abundant granule to silt-sized particles of coal. The total sulphur contents of these rocks is very low and indicates either that only small amounts of deposited organic matter were labile, or …