Physical Sciences and Mathematics Commons^™

Red Imported Fire Ant Impacts On Wildlife: A Decade Of Research, C. R. Allen, D. M. Epperson, A. S. Garmestani

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

The negative impacts of biological invasion are economically and ecologically significant and, while incompletely quantified, they are clearly substantial. Ants (family Formicidae) are an important, although often overlooked, component of many terrestrial ecosystems. Six species of ants are especially striking in their global ability to invade, and their impacts. This paper focuses on the impacts of the most destructive of those species, the red imported fire ant (Solenopsis invicta), and focuses on impacts on native vertebrates. Red imported fire ants often become the dominant ant species in infested areas outside of their native range due to their aggressive …

A Graph Model For Dynamicwaveband Switching In Wdm Mesh Networks, Mengke Li, Byrav Ramamurthy

CSE Conference and Workshop Papers

We investigate the problem of waveband switching (WBS) in a wavelength-division multiplexing (WDM) mesh network with dynamic traffic requests. To solve the WBS problem in a homogeneous dynamic WBS network, where every node is a multi-granular optical cross-connect (MG-OXC), we construct an auxiliary graph. Based on the auxiliary graph, we develop two heuristic on-line WBS algorithms with different grouping policies, namely the wavelength-first WBS algorithm based on the auxiliary graph (WFAUG) and the waveband-first WBS algorithm based on the auxiliary graph (BFAUG). Our results show that the WFAUG algorithm outperforms the BFAUG algorithm.

Imsh: An Iterative Heuristic For Srlg Diverse Routing In Wdm Mesh Networks, Ajay Todimala, Byrav Ramamurthy

CSE Conference and Workshop Papers

Survivable routing of a connection involves computation of a pair of diverse routes such that at most one mute fails when failures occur in the network topology. A subset of links in the network that share the risk of failure at the same time are said to belong to a Shared Risk Link Group (SRLG) [3]. A network with shared risk link groups defined over its links is an SRLG network. A failure of an SRLG is equivalent to the failure of all the links in the SRLG. For a connection to he survivable in an SRLG network its working …

Survivable Traffic Grooming With Path Protection At The Connection Level In Wdm Mesh Networks, Wang Yao, Byrav Ramamurthy

CSE Conference and Workshop Papers

Survivable traffic grooming (STG) is a promising approach to provide reliable and resource-efficient multigranularity connection services in wavelength division multiplexing (WDM) optical networks. In this paper, we study the STG problem in WDM mesh optical networks employing path protection at the connection level. Both dedicated protection and shared protection schemes are considered. Given the network resources, the objective of the STG problem is to maximize network throughput. To enable survivability under various kinds of single failures such as fiber cut and duct cut, we consider the general shared risk link group (SRLG) diverse routing constraints. We first resort to the …

Rerouting Schemes For Dynamic Traffic Grooming In Optical Wdm Mesh Networks, Wang Yao, Byrav Ramamurthy

CSE Conference and Workshop Papers

Traffic grooming in optical WDM mesh networks is a two-layer routing problem to effectively pack low-rate connections onto high-rate lightpaths, which, in turn, are established on wavelength links. In this work, we employ the rerouting approach to improve the network throughput under the dynamic traffic model. We propose two rerouting schemes, rerouting at lightpath level (RRAL) and rerouting at connection level (RRAC). A qualitative comparison is made between RRAL and RRAC. We also propose the critical-wavelength-avoiding one-lightpath-limited (CWA-1L) and critical-lightpath-avoiding one-connection-limited (CLA-1C) rerouting heuristics, which are based on the two rerouting schemes respectively. Simulation results show that rerouting reduces the …

Maximizing Resource Sharing In Wdm Mesh Networks With Path-Based Protection And Sparse Oeo Regeneration, Xi Yang, Byrav Ramamurthy, Lu Shen

CSE Conference and Workshop Papers

We propose a resource-sharing scheme that supports three kinds of sharing scenarios in a WDM mesh network with path-based protection and sparse OEO regeneration. Several approaches are used to maximize the sharing of wavelength-links and OEO regenerators.

Survivable Traffic Grooming With Differentiated End-To-End Availability Guarantees In Wdm Mesh Networks, Wang Yao, Byrav Ramamurthy

CSE Conference and Workshop Papers

Traffic grooming is critical in WDM optical metropolitan area networks (MANS), where low-rate connections are packed onto high-rate wavelength paths (lightpaths). Various applications in the MAN demand different levels of reliability. Therefore, it is necessary to provision connections with differentiated reliability guarantees in the MAN. In this paper, we first present an analytical model to calculate the availability of connections using different protection schemes in WDM optical MANs with general mesh topologies. Then we propose and simulate two grooming algorithms which can provision availability guaranteed connections based on per-connection requirements.

Infrastructure Support For Controlled Experimentation With Software Testing And Regression Testing Techniques, Hyunsook Do, Sebastian Elbaum, Gregg Rothermel

CSE Conference and Workshop Papers

Where the creation, understanding, and assessment of software testing and regression testing techniques are concerned, controlled experimentation is an indispensable research methodology. Obtaining the infrastructure necessary to support such experimentation, however, is difficult and expensive. As a result, progress in experimentation with testing techniques has been slow, and empirical data on the costs and effectiveness of techniques remains relatively scarce. To help address this problem, we have been designing and constructing infrastructure to support controlled experimentation with testing and regression testing techniques. This paper reports on the challenges faced by researchers experimenting with testing techniques, including those that inform the …

Using Source-Code Analysis To Help End-User Programmers Create Dependable Software, Gregg Rothermel

CSE Conference and Workshop Papers

Not long ago, most software was written by professional programmers, who could be presumed to have an interest in software engineering methodologies and in tools and techniques for improving software dependability. Today, however, a great deal of software is written not by professionals but by end-users, who create applications such as multimedia simulations, dynamic web pages, and spreadsheets. Applications such as these are often used to guide important decisions or aid in important tasks, and it is important that they be sufficiently dependable, but evidence shows that they frequently are not. For example, studies have shown that a large percentage …

Evaluating Consistency Algorithms For Temporal Metric Constraints, Yang Shi, Anagh Lal, Berthe Y. Choueiry

CSE Conference and Workshop Papers

We study the performance of some known algorithms for solving the Simple Temporal Problem (STP) and the Temporal Constraint Satisfaction Problem (TCSP). In particular, we empirically compare the Bellman-Ford (BF) algorithm and its incremental version (incBF) by (Cesta & Oddi 1996) to the ΔSTP of (Xu & Choueiry 2003a). Among the tested algorithms, we show that ΔSTP is the most efficient for determining the consistency of an STP, and that incBF combined with the heuristics of (Xu & Choueiry 2003b) is the most efficient for solving the TCSP. We plan to improve ΔSTP by exploiting incrementality as in incBF and …

Evaluating Consistency Algorithms For Temporal Metric Constraints, Yang Shi, Anagh Lal, Berthe Y. Choueiry

CSE Conference and Workshop Papers

Focus: Networks of temporal metric constraints

Task: Evaluating the performance of algorithms for:

·Determining the consistency of the Simple Temporal Problem (STP)

·Finding the minimal network of the Temporal Constraint Satisfaction Problem (TCSP)

Future: Enhance triangulation-based algorithms with incrementality

Golf Course Pollution Prevention Guide, Iowa Waste Reduction Center

Iowa Waste Reduction Center Book Gallery

According to the Environmental Protection Agency (EPA), pollution prevention can be defined as: “The use of materials, processes, or practices that reduces or eliminates the creation of pollutants or wastes at the source.” Pollution prevention represents a shift away from the old school of thought, “pollution control,” in which waste was not dealt with until after it was generated. Through pollution prevention, we look at the processes that generate the waste to see if we can avoid creating a waste in the first place, or at least reduce the hazardous nature of the waste. When this is not possible, the …

Self Consistent Field, Scf Homo And Lumo For Cuo2 Layer In Cuprates, H. Sahibudeen, Juana Acrivos

Faculty Publications, Chemistry

Before photoemission studies [1995] measured the symmetry of layer cuprate conduction states along the (xy),(-x-y) direction of the unit cell, a SCF analysis [1993] gave the symmetry of the HOMO & LUMO showing O:2pxy-O:2pxy charge de-localization for the conducting CuO2 layer in a superconducting cuprate (T'-Nd2CuO4 in the crystal field of point charges of nearest neighbor unit cells). The predictive power of MO calculations are applied now to understand the concept of valence and periodic lattice distortions commonly found in these solids [2003].

Design And Preparation Of Antireflection And Reflection Optical Coatings, Özlem Duyar, H. Zafer Durusoy

Turkish Journal of Physics

In this study, reflective and antireflective coatings were designed and simulated. Optical transmission and reflection values were deduced with a matrix formulation via a personal computer. It was found that the number of layers affects the optical performance. The width of the high-reflectance region in the reflectance curves decreases, while its height increases with the increasing number of layers for the reflective coating design. The antireflection coatings transmit about 99.89% in a broad high-pass band at the central wavelength of \lambda_{0} = 450 nm. In addition, simulated Fabry-Perot filters result in a single sharp transmittance peak at the desired central …

Comparative Study Of First Two Harmonics In Cosmic Ray Intensity For The Period 1964-95, Rekha Agarwal Mishra, Rajesh K. Mishra

Turkish Journal of Physics

The Deep River neutron monitor data has been harmonically analyzed for the period 1964--95 covering three solar cycles 20, 21 and 22, looking for a long term trend of the diurnal and semi-diurnal anisotropies of cosmic ray intensity on geomagnetically 60 quiet days. The amplitude of both the harmonics remains statistically constant during 1964-70. The amplitudes of the first harmonic is found to be low during 1965, 1967, 1976-77, 1986-87, 1991, 1993 and 1995. The amplitude of diurnal anisotropy acquired exceptionally large values in 1985, whereas semi-diurnal anisotropy acquired large values in 1974-75 and in 1984, which coincided with epochs …

Structure And Dielectric Behaviour Of Barium Cupro Molybdate Ceramic, N. G. Durge, M. S. Nadkarni, S. V. Salvi

Turkish Journal of Physics

The ceramic of new perovskite Ba (Cu_{1/2} Mo_{1/2}) O_3 has been synthesized at 1200 °C for 24 hours. The XRD analysis indicates an ordered hexagonal structure, which is attributed to large valency difference between octahedral cations. The IR spectrum reveals the presence of Cu-O-Mo ordered bond. The room temperature relaxation spectra imply a large conductivity term and multiple `Debye terms' at low frequencies. This is attributed to presence of the space charge. The variation of dielectric constant with temperature has been investigated from room temperature to 800 K. The diffusivity constant equal to 1 implies normal ferroelectric behaviour near room …

Rectification Of Thermal Fluctuations In Ideal Gases, Alejandro Garcia, P. Meurs, C. Van De Broeck

Faculty Publications

We calculate the systematic average speed of the adiabatic piston and a thermal Brownian motor, introduced by C. Van den Broeck, R. Kawai and P. Meurs [Phys. Rev. Lett. 93, 090601 (2004)], by an expansion of the Boltzmann equation and compare with the exact numerical solution.

New Insights Into The Binding Site Formation And The Performance Of Molecularly Imprinted Polymers, Hyunjung Kim

LSU Doctoral Dissertations

Molecularly imprinted polymers (MIPs) are finding important applications in the field of separation science, catalysis, sensor, and immunoassays. To optimize the performance of the MIPs, it is essential to understand the underlying mechanism of the process. This research focuses on understanding binding site formation and performance, and improvement of the MIPs. Chapter 1 introduces the concept of the MIPs, and binding isotherm and affinity distribution of heterogeneous binding sites in the MIPs. Chapter 2 describes fundamental studies conducted to understand the binding site formation of the MIPs. The number of binding sites (N) and the number average association constant (Kn) …

Applications Of The Titanium Catalyzed Cyclocarbonylation Towards Natural Product Syntheses, Jongtae Yang

LSU Doctoral Dissertations

Recently an efficient methodology, a hetero Pauson-Khand reaction, based on titanium-catalyzed cyclocarbonylation of tethered enals for the general preparation of ¥ã-butyrolactone rings, which are typically embedded in polycyclic systems of many natural products was reported. To demonstrate this new strategy, the total syntheses of the natural products asteriscanolide and ginkgolide were investigated. The first part of this work is dedicated to synthetic efforts toward the total synthesis of asteriscanolide. Approaches highlighted by the [2,3]-Wittig rearrangement, the thermal silyloxy-Cope rearrangement, and a titanium-catalyzed cyclocarbonylation, which is the pivotal step to afford the ¥ã-butyrolactone ring. This study firmly established the utility of …

Application Of Disturbance Theory To Assess Impacts Associated With A Three-Dimensional Seismic Survey In A Freshwater Marsh In Southwest Louisiana, Aaron Stuard Bass

LSU Doctoral Dissertations

This study examined various practical and theoretical aspects of disturbance in a coastal wetland marsh in southern Louisiana. A literature review approached disturbance ecology from both practical and theoretical perspectives and assessed its applicability to developing broad predictive models. However, specific knowledge of environmental variables, competitive relationships, and the interactive effects of multiple disturbances are required for meaningful usage of these models. The Lacassine National Wildlife Refuge (LNWR) proved to be an ideal laboratory to test various aspects of ecological disturbance theory. I found that the primary disturbances affecting the LNWR have been hurricanes, droughts, water-level manipulations, prescribed burning, oil …

Synthesis, Separation And Reactivities Of Multidentate Phosphine Ligands And Investigation Into Dirhodium Hydroformylation And Hydrocarboxylation Catalysis, David Aubry

LSU Doctoral Dissertations

A dirhodium homogeneous hydroformylation catalyst based on a tetraphosphine ligand, rac-Et₂PCH₂CH₂P(Ph)CH₂P(Ph)CH₂CH₂PEt₂, rac-et,ph-P4, is under investigation. The ligand synthesis produces a racemic mixture and a facile and efficient method of separation of the racemic and meso diastereomers was achieved through reaction of et,ph-P4 with two equivalents of NiCl₂ in EtOH to yield an almost quantitatively isolable precipitate of meso-Ni₂Cl₄(et,ph-P4) and the soluble rac-Ni₂Cl₄(et,ph-P4). Subsequent cyanolysis of these complexes liberates the et,ph-P4 ligand, and the …

Effects Of Localization And Amplification On Intensity Distribution Of Light Transmitted Through Random Media, Alexey Yamilov, Hui Cao

Physics Faculty Research & Creative Works

We numerically study the statistical distribution of intensity of light transmitted through quasi-one-dimensional random media by varying the dimensionless conductance g and the amount of absorption or gain. A markedly non-Rayleigh distribution is found to be well fitted by the analytical formula of Nieuwenhuizen et al. [Phys. Rev. Lett. 74, 2674 (1995)] with a single parameter g′ . We show that in the passive random system g′ is uniquely related to g , while in amplifying or absorbing random media g′ also depends on the gain or absorption coefficient.

Highest-Quality Modes In Disordered Photonic Crystals, Alexey Yamilov, Hui Cao

Physics Faculty Research & Creative Works

We studied the modes of the highest-quality factor Qm in disordered photonic crystals. by varying the strength of disorder, we identified five different scaling regimes of the ensemble averaged (Qm) with the system size. For sufficiently large systems, (Qm) reaches the maximum at some finite degree of disorder, where its value is comparable to the quality factor of an intentionally introduced single defect at the center of a photonic band gap. Near this optimal degree of disorder, we predict a superexponential increase of (Qm) with the system size, due to migration of the frequencies of the highest-quality modes toward the …

Validation Of A Sensitivity Performance Index Test Protocol And Evaluation Of Colour Doppler Sensitivity For A Range Of Ultrasound Scanners, Jacinta Browne, Amanda Watson, Peter Hoskins, Alex Elliott

Articles

The ability to detect flow is the most crucial aspect of an ultrasound (US) system because, if flow cannot be detected, no other aspect of performance matters. The objectives of this study were to validate a Doppler “sensitivity performance index,” a figure of merit, and to determine if it could be used to differentiate colour Doppler sensitivity performance in scanners of varying complexity. The sensitivity performance index was developed to give a combined measure of related aspects of sensitivity, such as the lowest detectable velocity, the vessel size and the penetration depth. The colour Doppler sensitivity was evaluated objectively as …

Capturing The Dialectic Between Principles And Cases, Kevin D. Ashley

Articles

Theorists in ethics and law posit a dialectical relationship between principles and cases; abstract principles both inform and are informed by the decisions of specific cases. Until recently, however, it has not been possible to investigate or confirm this relationship empirically. This work involves a systematic study of a set of ethics cases written by a professional association's board of ethical review. Like judges, the board explains its decisions in opinions. It applies normative standards, namely principles from a code of ethics, and cites past cases. We hypothesized that the board's explanations of its decisions elaborated upon the meaning and …

Laser Writing Of Semiconductor Nanoparticles And Quantum Dots, Massimo F. Bertino, Raghuveer Reddy Gadipalli, J. Greg Story, C. G. Williams, Guo-Hui Zhang, Chariklia Sotiriou-Leventis, Akira Tokuhiro, Suchi Guha, Nicholas Leventis

Physics Faculty Research & Creative Works

Silica aerogels were patterned with CdS using a photolithographic technique based on local heating with infrared (IR) light. The solvent of silica hydrogels was exchanged with an aqueous solution of the precursors CdNO₃ and NH₄ OH, all precooled to a temperature of 5°C. Half of the bathing solution was then replaced by a thiourea solution. After thiourea diffused into the hydrogels, the samples were exposed to a focused IR beam from a continuous wave, Nd-YAG laser. The precursors reacted in the spots heated by the IR beam to form CdS nanoparticles. We lithographed features with a diameter of …

Dynamics Of Complex Polymer Solutions: Putting Diffusion To Work And Exploring Rigid Rod Diffusion, Garrett John Doucet

LSU Doctoral Dissertations

This dissertation is concerned with random coil and rodlike polymer diffusion in complex solutions. The development of fluorescence photobleaching recovery, FPR, as a technique to determine polymer molecular weight distributions by measuring the diffusion distribution and converting it to a molecular weight distribution using a calibration curve is first covered. Fluorescently tagged probes were individually dissolved in polymer solutions at negligible amounts and measured with FPR to construct the calibration curve of self-diffusion vs. molecular weight. Once calibration curves were constructed, bimodal distributions were separated using the matrices corresponding to the calibration curves. The diffusion of the probes and separation …

Smeared Phase Transition In A Three-Dimensional Ising Model With Planar Defects: Monte Carlo Simulations, Rastko Sknepnek, Thomas Vojta

Physics Faculty Research & Creative Works

We present results of large-scale Monte Carlo simulations for a three-dimensional Ising model with short-range interactions and planar defects, i.e., disorder perfectly correlated in two dimensions. We show that the phase transition in this system is smeared, i.e., there is no single critical temperature, but different parts of the system order at different temperatures. This is caused by effects similar to but stronger than Griffiths phenomena. In an infinite-size sample there is an exponentially small but finite probability to find an arbitrary large region devoid of impurities. Such a rare region can develop true long-range order while the bulk system …

Ultraviolet Photonic Crystal Laser, Alexey Yamilov, Hui Cao, Robert P. H. Chang, Xiaohua Wu, Xang Liu, Shuyou Li, Vinayak P. Dravid

Physics Faculty Research & Creative Works

We fabricated two-dimensional photonic crystal structures in zinc oxide films with focused-ion-beam etching. Lasing is realized in the near-ultraviolet frequency at room temperature under optical pumping. From the measurement of lasing frequency and spatial profile of the lasing modes, as well as the photonic band structure calculation, we conclude that lasing occurs in the strongly localized defect modes near the edges of photonic band gap. These defect modes originate from the structure disorder unintentionally introduced during the fabrication process. ©2004 American Institute of Physics

Electronic Structural Investigations Of Bi- And Polymetallic Complexes Using Quantum Mechanical Methods, Zakiya Sheni Wilson

LSU Doctoral Dissertations

Understanding the dynamics influencing chemical reactivity is essential for properly exploiting matter into more useful purposes. In that manner, computational chemistry is a tool frequently used to study chemical properties at the most intimate level, i.e. the single molecule.

With this work, we probe the chemistry governing a variety of multi-faceted bi- and polymetallic compounds. To date our research consists of four major projects: bimetallic rhodium-catalyzed hydroformylation and aldehyde-water shift hydrocarboxylation catalysis; a novel linear M-H-M interaction in a bridged bis(dialkylphosphino)methane complex of nickel; and CeBe₁₃, a heavy fermion conductor. Computational investigations on these systems allow us to …