Physical Sciences and Mathematics Commons^™

Infinite-Randomness Critical Point In The Two-Dimensional Disordered Contact Process, Thomas Vojta, A. Farquhar, J. Mast

Physics Faculty Research & Creative Works

We study the nonequilibrium phase transition in the two-dimensional contact process on a randomly diluted lattice by means of large-scale Monte Carlo simulations for times up to 1010 and system sizes up to 8000×8000 sites. Our data provide strong evidence for the transition being controlled by an exotic infinite-randomness critical point with activated (exponential) dynamical scaling. We calculate the critical exponents of the transition and find them to be universal, i.e., independent of disorder strength. The Griffiths region between the clean and the dirty critical points exhibits power-law dynamical scaling with continuously varying exponents. We discuss the generality of our …

Synthesis Of The Bicyclic Core Of Pyrrolizidine Alkaloids, Fatmagul Tuluoglu

Master's Theses and Doctoral Dissertations

Pyrrolizidine alkaloids are a large class of natural products whose members exhibit a variety of biological properties including potential applications toward the treatment of cancer, diabetes, and viral infections such as HIV. In addition, some of these compounds exhibit insect antifeedant activity, and so have potential applications in the agricultural industry for the protection of crops.

For these reasons, we were interested in developing a method to form the bicyclic alkaloid core that could be functionalized to generate many pyrrolizidine alkaloids. Specifically, our goal was to synthesize the pyrrolizidine B-ring by a novel McMurry cyclization strategy (Scheme 1). The synthesis …

Identification Of Changes In The Surface Of Textiles Subjected To Plasma Chemical Treatment Using Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy, Joslyn Diana Kirkland

Master's Theses and Doctoral Dissertations

Plasma chemical oxidation has been proposed as a “nondestructive” method for preparing samples from archaeological materials for radiocarbon dating using accelerator mass spectrometry. However, the chemical effects of low-temperature, low-pressure plasma discharges on fragile archaeological materials are not understood. It is believed that reactions only occur at the surface of the treated samples. Therefore, we have used Fourier transform infrared spectroscopy with attenuated total reflectance sampling (ATR-FTIR) to examine changes in the chemical nature of the surface of representative modern and archaeological samples upon plasma treatment. Samples that were treated with destructive wet chemical methods, e.g., treatment with sodium hydroxide …

Role Of Aromatic Pi-Stacking On The Aggregation Of Human Islet Amyloid Polypeptide (Hiapp), Srikanth Reddy Konda

Master's Theses and Doctoral Dissertations

Human islet amyloid polypeptide (hIAPP) is secreted in the β-cells of the pancreas, which also secretes insulin. In type 2 diabetes mellitus, hIAPP undergoes self-aggregation, forming fibrils. This self-aggregation is cytotoxic and is thought to be linked to type 2 diabetes mellitus by causing β-cell membrane destruction. The N-terminus of hIAPP (1-19) contains a binding site (residues 14-18) for self-aggregation. Aggregation is thought to be mediated by pistacking interactions between phenylalanine residues of hIAPP. In this study, the hIAPP 1-19 sequence was modified by replacing phenylalanine with alanine and naphthylalanine, to study if the modification of the aromatic side chain …

Insulin Based Inhibitors Of Human Islet Amyloid Polypeptide (Hiapp) And Their Effect On Hiapp- Mediated Membrane Damage In Type 2 Diabetes Mellitus, Durgaprasad Peddi

Master's Theses and Doctoral Dissertations

Amylin (Islet Amyloid Polypeptide, IAPP) is a 37 amino acid polypeptide, co-secreted with insulin from pancreatic beta cells, that plays a role in the damage of cell membranes by forming amyloid fibrils in Type 2 diabetes. Insulin has been found to inhibit hIAPP (Human Islet Amyloid Polypeptide) aggregation. The HLVEALYLVC amino acid region of insulin contacts hIAPP near the N-terminus. Truncated and modified analogs of insulin containing the binding region (VEALYLV, VEALFLV and EALYLV) were synthesized and purified, and their actions were studied on model lipid membranes in the presence of hIAPP 1-19 and hIAPP 1-37.

Do Laminated Sediment-Gravity-Flow Deposits On The Antarctic Peninsula Continental Shelf Record Ice Sheet Grounding Events?, Vincent Clyde Adams

LSU Master's Theses

Barker and Camerlenghi (2002) proposed that drifts on the continental rise of the Antarctic Peninsula may record a high-resolution record of ice-sheet expansions on the adjacent continental shelf. In their view, laminated sediments were deposited during glacial periods, whereas during interglacial periods, sediment supply to drifts was negligible. As a consequence of low sediment supply, the tops of laminated sequences were bioturbated. Therefore, a bioturbated-laiminated couplet should represent a complete glacial cycle. Bioturbated and laminated (B-L) sediment couplets were compiled from cores at two drift sites obtained from Ocean Drilling Program (ODP) Leg 178 Sites 1095, 1096, and 1101. If …

Environmental Influences On The Mobility And Speciation Of Arsenic In The Geothermal Waters Of El Tatio Geyser Field, Chile, Lindsey R. Johnson

LSU Master's Theses

El Tatio geyser field, northern Chile, impacts regional water quality, policy, and agricultural commerce due to the geothermal waters containing high concentrations of naturally-occurring arsenic (As). In the circumneutral pH, non-sulfidic thermal waters at El Tatio, dissolved arsenite [As(III)] dominates geyser discharge water upstream, but dissolved arsenate [As(V)] dominates downstream. Microbial mats and sediments were analyzed for changes in As speciation using X-ray spectroscopy methods, such as XANES and EXAFS at both the As and Fe K-edges, combined with ATR-FTIR spectroscopy and molecular genetics, to understand As cycling. The sediments and microbial mats were dominated by As(V) speciated as both …

Creating An Empirically Derived Community Resilience Index Of The Gulf Of Mexico Region, Ariele Nicole Baker

LSU Master's Theses

As coastal areas increase in populations there is an increasing need to determine what community characteristics are most resilient to coastal disasters. This research proposes two methods to quantify community resilience. The factor analysis method results in a weighted additive index model of six variables to derive community resilience. The index places every community in the Gulf of Mexico on a scale from 0-1. The most resilient counties in the Gulf of Mexico region were found to be Hillsborough, FL, Pinellas, FL, Sarasota, FL, Hernando, FL, Okaloosa, FL, Kenedy, TX, and Jefferson, LA with a resilience score of 1. The …

A Novel Synthesis And Characterization Of Fluorescein Isothiocyanate Labeled Poly(Styrenesulfonate Sodium Salt), Xiaowei Tong

LSU Master's Theses

The diffusion of polyelectrolytes in low-salt or salt-free aqueous solutions is a controversial question. It has been intensively discussed since it was discovered in 1978. Most previous experimental data were obtained from dynamic light scattering (DLS), whose precision, however, was reduced by stringent sample preparation and weak scattering of polyelectrolyte in low-salt solution. For the most commonly studied polyelectrolyte, poly(styrenesulfonate sodium salt) (NaPSS), the harsh polymerization condition and the manufacturing procedure lead to hydrophobic defects and aggregations, which also block a correct insight about the diffusion of polyelectrolyte. In contrast to DLS, fluorescence photobleaching recovery (FPR) directly looks on the …

A Comparative Study Of Geometry Curricula, Robyn Williams Carlin

LSU Master's Theses

In the United States, geometry has long been offered to high school students in the tenth grade. Attempts have been made in recent years to expand the role of geometry across grades Pre-K through twelve. However, based on the latest TIMSS results, although students in the United States made gains in most content areas, they still struggle with geometric concepts compared to their counterparts in other nations of the world, primarily those in certain Asian countries like Singapore and China. We argue that the structure of the curriculum and the instructional strategies used in these countries may lead to more …

Seasonal Variability In Absorption And Fluorescence Properties Of Chromophoric Dissolved Organic Matter In The Barataria Basin, Louisiana, Usa, Shatrughan Singh

LSU Master's Theses

Absorption and fluorescence measurements of chromophoric dissolved organic matter (CDOM) were examined along a transect containing 36 sampling stations in the Barataria Basin during high and low conditions to observe seasonal variation in these optical properties. The objectives of this study were (i) to observe CDOM variability in Barataria Basin in variable flow (high and low) conditions, and to characterize the CDOM, (ii) to identify the constituents of CDOM and to model CDOM compositional variability in the Barataria Basin using parallel factor analysis (PARAFAC). CDOM–salinity relationships were non-conservative in lower and upper part of the transect; however a conservative inverse …

Comparisons Of Boosted Regression Tree, Glm And Gam Performance In The Standardization Of Yellowfin Tuna Catch-Rate Data From The Gulf Of Mexico Lonline [Sic] Fishery, Shane Abeare

LSU Master's Theses

Recent advances in statistical understanding have focused fisheries research attention on addressing the theoretical and statistical issues encountered in standardizing catch-rate data. Similarly, the present study evaluates the performance of boosted regression trees (BRT), the product of recent progress in machine learning technology, as a potential tool for catch-rate standardization. The BRT method provides a number of advantages over the traditional GLM and GAM approaches including, but not limited to: robust parameter estimates as a result of the integrated stochastic gradient boosting algorithm; model structure learned from data and not determined a priori, thereby avoiding assumptions required for model specification; …

Resiliency Of New Orleans Following Hurricane Katrina: A Study Of Communities Three Years After The Storm, Lauren Marie Defrank

LSU Master's Theses

In 2005, Hurricane Katrina and subsequent levee failures produced widespread flooding in New Orleans, Louisiana and forced the evacuation of most of the local population. This event allowed for the study of the community’s resilience, or the ability of a system to absorb changes or perturbations and still function. Statistical analysis and case studies were used to study resilience and answer the following questions. Can natural community recovery models be used when evaluating the population recovery of a human community following a disturbance? Given that there are variations in population recovery patterns, what factors account for this difference in recovery? …

Impact Of Intrafraction Motion On Post-Mastectomy Tomotherapy Of The Chest Wall, Shima Ito

LSU Master's Theses

Purpose: The present work investigates the impact of intrafraction motion of the chest wall due to respiration on Post Mastectomy Radiotherapy (PMRT) with TomoTherapy. The hypothesis of this work is that the impact of intrafraction motion on TomoTherapy PMRT will be insignificant as (1) the largest intrafraction movement of the chest wall (CW) in the medial-lateral, anterior-posterior, and superior-inferior dimensions will not exceed 1 cm and (2) that 95% of in-vivo CW point doses on the patient surface will be within 5% of calculated dose and all doses within 10% of calculated dose. Methods: 4DCT scans were acquired and intrafraction …

Mathematical Aids Epidemic Model: Preferential Anti-Retroviral Therapy Distribution In Resource Constrained Countries, Nadia Abuelezam

HMC Senior Theses

HIV/AIDS is one of the largest health problems the world is currently facing. Even with anti-retroviral therapies (ART), many resource-constrained countries are unable to meet the treatment needs of their infected populations. ART-distribution methods need to be created that prevent the largest number of future HIV infections. We have developed a compartment model that tracks the spread of HIV in multiple two-sex populations over time in the presence of limited treatment. The model has been fit to represent the HIV epidemic in rural and urban areas in Uganda. With the model we examine the spread of HIV among urban and …

Capillary Electrophoretic Separations Of Enzyme Inhibitors With Activity-Based Detection, Xiaoyan Yan

LSU Master's Theses

A technique for separating and detecting enzyme inhibitors was developed using capillary electrophoresis with an enzyme microreactor. The on-column enzyme microreactor was constructed using one or two NdFeB magnets in two configurations to immobilize alkaline phosphatase-coated superparamagnetic beads with diameters of 2.8 µm inside a capillary before the detection window. Enzyme inhibition assays were performed by injecting a plug of inhibitor into a capillary filled with an alkaline phosphatase substrate, AttoPhos. Product generated in the enzyme microreactor was detected by laser-induced fluorescence. Inhibitor zones electrophoresed through the capillary, passed through the enzyme microreactor, and were observed as negative peaks due …

Moderating Effects Of Knowledge, Gender, And Education On The Relationship Between Environmental Value Orientation And Support For Louisiana Coastal Restoration, Meya Voorhies Holloway

LSU Master's Theses

Coastal Louisiana marshes are eroding at a rate equivalent to one football field every thirty minutes. It is vital to understand the perceptions of the American public regarding this issue. I conducted a self-administered mail survey during the spring of 2006. The survey was sent to 4,500 residents living in the Mississippi River Valley. The survey was used to identify respondents environmental value orientations, assess respondents attitudes with regards to support for restoration funding for Louisiana’s coastal wetlands, and to determine if outside moderating effects occurred to make respondents with specific value orientations (Anthropocentric or Biocentric) more likely to support …

Preface To The Proceedings Of The Xxvi International Conference On Photonic, Electronic And Atomic Collisions, Ann Orel, Anthony F. Starace, Dragan Nikolić, Nora Berrah, Thomas Gorczyca, Emanuel Kamber, John A. Tanis

Anthony F. Starace Publications

The XXVIth International Conference on Photonic, Electronic and Atomic Collisions was held on the campus of Western Michigan University (WMU) in Kalamazoo during 22-28 July 2009. Kalamazoo, the home of a major state university amid pleasant surroundings, was a delightful place for the conference. The 473 scientific participants, 111 of whom were students, had many fruitful discussions and exchanges that contributed to the success of the conference. Participants from 43 countries made the conference truly international in scope.

The plenary lectures and the progress and special reports bridged the gap between the different fields of collision physics, making it possible …

Scaling Up Of Co2 Fluxes From Leaf To Canopy In Maize-Based Agroecosystems, Timothy J. Arkebauer, Elizabeth A. Walter-Shea, Mark A. Mesarch, Andrew E. Suyker, Shashi Verma

School of Natural Resources: Faculty Publications

Carbon dioxide fluxes are being measured in three maize-based agroecosystems in eastern Nebraska in an effort to better understand the potential for these systems to sequester carbon in the soil. Landscape-level fluxes of carbon, water and energy were measured using tower eddy covariance systems. In order to better understand the landscape-level results, measurements at smaller scales, using techniques promoted by John Norman, were made and scaled up to the landscape-level. Single leaf gas exchange properties (CO₂ assimilation rate and stomatal conductance) and optical properties, direct and diffuse radiation incident on the canopy, and photosynthetically active radiation (PAR) reflected and …

Impact Of Empire Expansion On Household Diet: The Inka In Northern Chile’S Atacama Desert, Sheila D. Vinton, Linda Perry, Karl J. Reinhard, Calogero M. Santoro, Isabel Teixeira-Santos

School of Natural Resources: Faculty Publications

The impact of expanding civilization on the health of American indigenous societies has long been studied. Most studies have focused on infections and malnutrition that occurred when less complex societies were incorporated into more complex civilizations. The details of dietary change, however, have rarely been explored. Using the analysis of starch residues recovered from coprolites, here we evaluate the dietary adaptations of indigenous farmers in northern Chile’s Atacama Desert during the time that the Inka Empire incorporated these communities into their economic system. This system has been described as ‘‘complementarity’’ because it involves interaction and trade in goods produced at …

Simulation Of Boundary Layer Trajectory Dispersion Sensitivity To Soil Moisture Conditions: Mm5 And Noah-Based Investigation, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

A System For Estimating Bowen Ratio And Evaporation From Waste Lagoons, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Near Surface Atmospheric Response To Simulated Changes In Land-Cover, Vegetation Fraction, And Soil Moisture Over Western Kentucky, Rezaul Mahmood

School of Natural Resources: Faculty Publications

No abstract provided.

Panarchy: Discontinuities Reveal Similarities In The Dynamic System Structure Of Ecological And Social Systems, Ahjond S. Garmestani, Craig R. Allen, Lance Gunderson

School of Natural Resources: Faculty Publications

In this paper, we review the empirical evidence of discontinuous distributions in complex systems within the context of panarchy theory and discuss the significance of discontinuities for understanding emergent properties such as resilience. Over specific spatial-temporal scale ranges, complex systems can configure in a variety of regimes, each defined by a characteristic set of self-organized structures and processes. A system may remain within a regime or dramatically shift to another regime. Understanding the drivers of regime shifts has provided critical insight into system structure and resilience. Although analyses of regime shifts have tended to focus on the system level, new …

General Formulation Of The Scattered Matter Waves By A Quantum Shutter, Yusuf Zi̇ya Umul

Turkish Journal of Physics

The scattering process of matter waves by a quantum shutter is investigated by using the spectrum integral representation. The scattered fields are expressed in terms of the Fresnel function. It is shown that the obtained equation gives the Moshinsky function for a one dimensional problem of the plane wave. Also a general integral representation is derived for two dimensional problems. The scattering of matter waves for some special wave-packets are examined analytically and numerically.

Effective Annealing Of Zno Thin Films Grown By Electrochemical Deposition Technique, Cevdet Coşkun, Harun Güney, Emre Gür, Sebahatti̇n Tüzemen

Turkish Journal of Physics

Wide and direct band gap ZnO thin films have been grown on conductive indium-tin-oxide (ITO) substrates by electrochemical deposition (ECD) technique using different growth parameters. High quality films in terms of crystallographic and optical characteristics have been obtained under a cathodic potential of -0.9 V; a pH of 5.2, using 0.1 M Zn(NO_3)_2 solution. Oxygen gas flow through the solution increased the growth rate and the quality of samples. Subsequent heat treatments at various temperatures for 30 minutes under dry N_2 gas flow show that the most suitable annealing temperature is 300 °C for these electrochemically deposited thin films on …

Combined Analysis Of Solar Neutrino Data Within The Rsfp Framework Together With New Kamland Data, Deni̇z Yilmaz

Turkish Journal of Physics

A combined analysis of solar neutrino data together with the new KamLAND data is presented in the RSFP framework. It is investigated how the allowed regions are effected from the new KamLAND data at different \mu B values. Limits on \mu B value is found at the different confidence level intervals.

Production Of Ybco Superconductor Sample By Powder-In-Tube Method (Pitm); And Effect Of Cd And Ga Doping On The System, Serkan Alagöz

Turkish Journal of Physics

In this study, YBa_2Cu_3O_{7-\delta} and Y_{0.5}X_{0.5}Ba_2Cu_3O_{7-\delta} (x = Ga, Cd) compounds are produced by Powder-In-Tube Method and electrical and physical characteristics of those samples were investigated. Following 3, 5 and 9 tons pressure applied to three sample groups (YBa_2Cu_3O_{7-\delta}, Y_{0.5}Cd_{0.5}Ba_2Cu_3O_{7-\delta}, Y_{0.5}Ga_{0.5}Ba_2Cu_3O_{7-\delta}), samples were examined via X-Ray diffraction, resistivity and SEM measurement. Considerable changes in Crystallographic properties of the YBCO samples, produced by using Powder-In-Tube Method for different pressure values, were observed. Under different magnetic fields conditions, resistance of the YBCO samples was measured and it was seen that samples had very pure and homogenous structure. Ga doping into YBCO composition …

Electrical Characterization And Relaxation Behavior Of Lithium-Indium-Phosphate Glasses Via Impedance Spectroscopy, M. V. N. V. D. Sharma, A. V. Sarma, R. Balaji Rao

Turkish Journal of Physics

Phosphate glasses with various compositions of lithium oxide and indium oxide were synthesized by melt quenching technique. The glass forming ability parameter K_{gl} was characterized by differential thermal analysis. The electrical measurements for all the glass samples were carried out in the frequency range of 10 Hz to 10^{6} Hz and at a temperature range of 393-513 K by the Impedance spectroscopy. Frequency dependent conductivity follows the power law. The ac conductivity increases with temperature following the Arrhenius law. Master curve in the scaling analysis suggesting the temperature independent conduction relaxation mechanism.

Generation Of Ultrafast Bright And Dark Pulse On Silicon Chip With Integrated Mach-Zehnder Interferometer Configuration, Jianwei Wu, Fengguang Luo

Turkish Journal of Physics

In this paper we propose and simulate ultrafast femtosecond bright and dark pulses, obtained simultaneously at the same center wavelength, based on silicon-on-insulator (SOI) waveguides in Mach-Zehnder interferometer (MZI) configuration; the ultrafast pulsed pump is injected into one MZI's arm and a continuous wave component (CW) is divided equally into the two MZI arms. Numerical results show that properties of the generated bright and dark pulses are strongly dependent on the launching optical powers of both the pump pulse and CW carriers, and on the waveguide length.