Digital Commons Network^™

Design Of A Passive Intensity Modulation Device For Bolus Electron Conformal Therapy, Erin Leanne Chambers

LSU Master's Theses

Purpose: To develop a process that can design an island block matrix that produces an intensity distribution (70-100%), which acceptably matches one planned for an intensity modulated (IM) bolus electron conformal therapy (ECT) patient. The intensity modulator concept is that electrons laterally scatter behind hexagonally-packed, small-diameter island blocks such that local intensity equals the fractional unblocked area.

Methods: A pencil beam algorithm (PBA) was used to calculate the modulated electron intensity created by varying diameter (d) of island blocks in a hexagonal array (separation r). Accuracy of the PBA model was assessed by comparing with Monte Carlo (MC) calculations. PBA …

A Mixed Consensus And Fuzzy Approach To Position Control Of Four-Wheeled Vehicles, Bita Hasheminezhad

LSU Master's Theses

Autonomous driving is a growing domain of intelligent transportation systems that utilizes communications to autonomously control cooperative vehicles. This thesis presents a multi-agent solution to the platoon control problem. First, an adaptive controller on linearized longitudinal dynamics of a vehicle is applied to assure vehicles are able to track their reference velocities. Then, an agent-based consensus approach is studied which enables multiple vehicles driving together where each vehicle can follow its predecessor at a close distance, safely. To deal with unexpected events, a fuzzy controller is added to the reference signal of the consensus controller. Simulation results are provided to …

Evaluation And Validation Of A Model To Predict The Effect Of Asphalt Mixtures And Vehicle Speed On Fuel Consumption Excess, Nirmal Dhakal

LSU Master's Theses

The primary objective of this study is to evaluate the effects of asphalt concrete (AC) properties and vehicle speed on fuel consumption excess using a Three-Dimensional (3D) Finite Element (FE) approach. Secondarily, the effect of pavement design characteristics on energy dissipation was studied. Finite element modeling was used to simulate three flexible pavements typically used for low traffic volume, medium traffic volume, and high traffic volume. The effect of asphalt concrete mixes with different binders and varying percentages of Reclaimed Asphalt Pavement (RAP) on fuel consumption excess was studied. The FE models were validated based on field stress and strain …

Psychometric Extension Of The Memory For Names Test, Heather Chance Foil

LSU Master's Theses

The purpose of this study was to re-evaluate the psychometric properties of the Memory for Names (Mem4Names) test among a sample of older adults without cognitive impairment. Mem4Names is a test of famous face recognition that was shown to be a reliable and valid measure of semantic memory in older adults both with and without cognitive impairment (Brouillette et al., 2011). The current study re-examined the psychometric properties of the Mem4Names test among 133 volunteers at Pennington Biomedical Research Center’s Institute for Dementia Research and Prevention. The study confirmed previously reported calculations of the test’s reliability by calculating Cronbach’s alpha …

Momentary Eddies, Leah Marie Hamel

LSU Master's Theses

Our lives are in a constant state of change, from the most intimate scale physically and emotionally to the world surrounding us externally. The relationships we build with ourselves, others, and the world surrounding us are important structures we carry with us throughout life. Momentary Eddies is a visual poem about the interconnectedness of our inner and outer landscapes. I have created a hauntingly dreamlike space that explores a landscape of emotions that are an entangled part of personal intimate relationships and how the emotional and physical topographies of these relationships connect to the environment surrounding us. These paper sculptures …

Mass Incarceration By Design: The Impacts Of Urban Renewal And Landscape Architecture's Absence On The Prison Industrial Complex And The Use Of Landscape Architecture As An Antidote To Mass Incarceration, Abigail P. Phillips

LSU Master's Theses

The work of landscape architects has both positive and negative social impacts and landscape architects can strive to intentionally design for positive social impact. This paper utilizes mass incarceration as a lens for discussing the social impact of landscape architecture. The crossroads of mass incarceration and design offer a unique opportunity for Landscape Architects to examine the impact of many urban renewal efforts on marginalized communities, the benefits of landscape architectural involvement in prison design, and the use of design as protest against inhumane structures. This paper is separated into three sections, one detailing the history of social justice and …

Convergence Of Excitatory And Inhibitory Projections In The Mouse Medial Geniculate Body, Blaise Andre Clarke

LSU Master's Theses

The medial geniculate body (MGB) is the target of excitatory and inhibitory inputs from several neural sources. Among these, the inferior colliculus (IC) is an important nucleus in the midbrain that acts as a nexus for many auditory pathways and projections, ascending and descending, throughout the rest of the central auditory system and provides both excitatory and inhibitory projections to the MGB. In addition, the thalamic reticular nucleus (TRN) is a major source of inhibition to the MGB, particularly in rodents. Finally, the auditory cortex (AC) is a major source of descending input to the MGB, providing direct excitation and …

A Geochronological And Stratigraphic Reconstruction Of The Middle Barataria Bay Receiving Basin, Joseph Ethan Thomas Hughes

LSU Master's Theses

Barataria Bay, one of the largest receiving basins for the Mississippi deltaic complex, is the location of a proposed river-sediment diversion for delta restoration. In order to determine how the sediment in the receiving-basin may respond to diversion flows, twenty-five sediment vibracores were collected from a 115 km2 study area located near Myrtle Grove and Bayou Dupont, southeast of New Orleans, LA. These cores were subject to multiple tests, including gamma bulk density scans, grain size analysis, and loss-on-ignition, in order to identify the lithology and stratigraphy. In addition, 137Cs and 14C dating techniques were employed in order to construct …

The Attentional Mechanisms Of Active Forgetting, Laura Lee Heisick

LSU Master's Theses

Recent work has shown that intentional forgetting of distracting, erroneous, or irrelevant information aids memory, and relies on active, effortful processes. Two experiments investigated the underlying attentional mechanisms that are active during directed forgetting (DF). Across both experiments, participants completed a modified item-method DF task, in which they received memory instructions to remember or forget individual images for a subsequent memory test. Participants studied items associated with remember or forget instructions before they were shown a subliminal presentation of target items. Finally, participants responded to probes by identifying briefly shown letters to assess how attention and item identity information are …

Combining Forage And Cover Crop Benefits From Cool-Season Annuals In The Southeastern United States, Dustin John Smith

LSU Master's Theses

Cow-calf operations in the southeastern United States (U.S.) are based on warm-season perennial grass pastures. Stored forage feeding during the non-grazing season constitutes more than half of a cattle operation’s annual expenses. Cool-season annuals can extend the grazing season, thereby reducing stored forage feeding. A two-year field trial was conducted to determine the forage potential of a variety of crops commonly used as winter cover crops in the southeastern U.S. The ten cover crop treatments included seven monocultures (annual ryegrass [Lolium multiflorum], rye [Secale cereal], oats [Avena sativa], triticale [Triticale hexaploide], tillage radish [Raphanus sativus], hairy vetch [Vicia villosa], crimson …

Pesticide Partitioning In Louisiana Wetland Aand Ricefield Sediment, Brendan Michael Marsh

LSU Master's Theses

Pesticides are used globally and are often found within bodies of water. The EPA investigates the potential environmental impact through computer modeling in order to help mitigate some of the regulatory burden of pesticide fate investigation. Currently when pesticides enter a water body, the Exposure Analysis Modeling System (EXAMS) estimates partitioning depth as 5 cm and assumes equal distribution. This assumption was tested with a wide variety of pesticides with varying Koc ranges and water solubilities. Savillex 150 ml Teflon tubes were filled with wetland and ricefield sediments with fresh and seawater as the aqueous phase. The seven pesticides tested …

Development Of Microfluidic Devices To Study Algal Chemotaxis And Long-Term Growth Dynamics, Benjamin Seth Roberts

LSU Master's Theses

Harmful algal blooms pose a threat to human health and the environment. Many complex factors influence their formation and development, and much is still unknown. One major influencing factor that is well-known yet poorly studied is algal chemotaxis. Many studies have examined chemotaxis in other organisms, but very little about chemotaxis in algae has been studied, largely because existing technology and assay techniques are inadequate. Microfluidics offers many possibilities for cell biology, and has been applied to the study of chemotaxis in other organisms already. These techniques can be applied to the study of algal chemotaxis as well. We present …

Transatlantic Trade And Investment Partnership: Implications To Global Wine Market, Natalia Antosova

LSU Master's Theses

Transatlantic Trade and Investment Partnership was first introduced in 2013, with the goal of liberalization of the trade and investments, better coordination of trade by specific regulations, enhancing intellectual property protection and lifting government’s impediments to trade. This Thesis is concerned on potential implications of the TTIP on the wine industry in the European Union and particular consequences related to EU wine producers. The literature review of this paper is developed with the purpose to bring general knowledge in the matter of the TTIP. In addition, linkages of the TTIP with the political economy are provided in the latter part …

Source Mechanism Analysis Of Single-Well Microseismic Data Using Full-Wavefield Moment Tensor Inversion, Trudy Watkins

LSU Master's Theses

Receiver angular coverage of microseismic sources occurring during hydraulic fracturing treatments is an important factor to consider when interpreting moment tensor inversion results. A horizontal receiver array can provide greater angular coverage of vertical failure planes than a vertical receiver array. The source orientation can be accurately determined if the array samples both sides of the failure plane. However, the compensated-linear-vector-dipole (CLVD) mechanism can be overestimated by up to ~40% for double-couple (DC) sources and the isotropic mechanism can be overestimated by ~70% for CLVD sources. Source mechanism constraints on the moment tensor inversion are used to mitigate the lack …

The Effect Of The Use Of The Students' First Language In Grammar Instruction: A Report On Student Preferences And Performance In The Target Language, Katherine Mickel

LSU Master's Theses

This study explores the effect of the use of the target language (TL) and the first language (L1) during grammar instruction in the foreign language classroom. There is limited evidence regarding the effect of language of instruction on TL acquisition (Tian & Macaro, 2012; Viakinnou-Brinson, Herron, Cole, & Haight, 2012; Antón & DiCamilla, 1999). However, this area warrants further research. As such, the present study investigates teacher language use (Spanish-only, English-only, or no restriction) during the explicit instruction of Spanish object pronouns (direct, indirect, and both combined) to measure the effect of each language condition on students’ object pronoun performance. …

Meeting Biopsychosocial Needs Of Individuals With Histories Of Multiple Adverse Childhood Experiences, Christine G. Morgan

LSU Master's Theses

According to Felitti and colleagues (1998), a significant portion of the general population has been exposed to adverse childhood experiences (ACEs) with subsequent and persistent, dose-related, negative consequences to physical and mental health. Debilitating disturbances to biopsychosocial well-being are significant and frequently lead to fatality in adulthood. After reviewing the prevalence and severity of ACEs, this thesis presents an overview of the literature outlining the biological, social, and psychological factors contributing to the development and progression of disease in the brain and body. Additionally, current trauma-informed interventions are summarized. Three experienced clinicians share practical advice for implementing evidence-based, trauma-informed mental …

Effects Of Temperature Segregation On The Denisity And Mechanical Properties Of Asphalt Mixtures, Pranjal Pravin Phaltane

LSU Master's Theses

Temperature differentials (TD) between the target laydown and actual laydown temperatures of asphalt paving mixtures have been noticed and measured since the late 1990s. Since then, numerous research studies conducted on the phenomena found inconclusive conclusions regarding the effects of TD on the initial pavement quality and the long-term performance. The objective of this study was to evaluate the effects of different levels of TD on the initial quality and the long-term performance of asphalt pavements by evaluating the core density and laboratory measured performance characteristics, respectively. Through the evaluation, it was also aimed to ascertain and establish allowable TD …

Simulating Behavioral Microcystin Impairment In Fish, Nicholas Richard Keeney

LSU Master's Theses

Fish experiencing blooms of the cyanobacteria genera Microcystis and Anabaena acquire microcystin and saxitoxin through ingestion of contaminated food and absorption of dissolved toxin. Even low chronic doses induce sensory and motor impairment—the impact of which is unquantified in wild populations. Here, I introduce Lagrangian particle models for cyanobacteria and fish which test the hypotheses that impairment symptoms suppress movement and growth. This is implemented within the Finite-Volume Coastal Ocean Model (FVCOM). Cyanobacteria particles move vertically according to mixing and buoyancy (a function of cellular reservoirs). Fish navigate the horizontal domain, foraging in high growth areas, and fleeing when toxin …

Initial Development And Validation Of The Student Wellbeing Teacher-Report Scales, Anthony Joseph Roberson

LSU Master's Theses

Given that youth mental health is associated with their success in school and in life more broadly, it is important that school-based psychological service providers embrace best-practice prevention and intervention strategies that target mental health when working with student populations. One line of study in this area has begun exploring the incorporation of a dual-factor model of mental health within universal screening systems in schools. The dual-factor model is differentiated from the traditional unidimensional mental health model, which focuses on the presence or absence of psychopathology, by conceptualizing mental health alternatively as consisting of both psychopathology and wellbeing dimensions. The …

Determining Seasonal Emergence, Growth Characteristics, And Control Programs For Henbit (Lamium Amplexicaule L.), Brandi C. Woolam

LSU Master's Theses

To provide for a weed-free seedbed, Louisiana crop producers typically apply a burndown herbicide four to six wk prior to seeding summer annual crops; however, these treatments often provide inadequate henbit (Lamium amplexicaule L.) control. Research was conducted in Louisiana to evaluate henbit emergence from north to south, compare growth of henbit accessions based on emergence date, and control with fall-applied residual herbicides. For the emergence study during the weeks of Oct 17 to Dec 12 at all locations in all years, soil temperatures at 2.5 cm averaged between 10 and 18.5 C. Henbit at densities of at least 50 …

In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley: Evaluation Of The Dorag Model And New Implications For Dolomitizing Fluids, John Michael Callen

LSU Master's Theses

The dolomitization and diagenetic history of Ordovician carbonates of southern Wisconsin has been studied for over a century. Previous studies attributed dolomitization to various single or multiple diagenetic factors and environments. The goal of the study was to resolve arguments regarding dolomitization models, including Badiozamani’s often cited but recently questioned mixing zone model, using LA-ICP-MS focusing on REE to determine the nature of dolomitizing fluids. Analysis revealed that particulate material incorporated into the dolomite affected the geochemical results of many of the samples. Integrating geochemical data with petrographic evidence for diagenetic history, the studied Decorah Formation dolomites were assigned to …

Decolonizing World History: Mis-Representations Of The Middle East In Secondary Social Studies Textbooks, Amanda Megan Schellhaas

LSU Master's Theses

This study utilizes content analysis to evaluate three United States High School World History textbook’s coverage of the Middle East since 1945 in order to determine if an authentic global approach to history is being utilized. This was determined by analyzing the amount of coverage that was dedicated to the Middle East, the focus of the narrative, and the portrayal of the Middle East. Analysis of the narrative content of the texts showed that coverage of the Middle East overall did not receive an equitable representation in comparison to other regions. The focus of this coverage centered on defining the …

A Contemporary Approach To A Classic Model: Exploring The Influence Of Local Interactions And Disturbance On Mangrove Forest Dynamics With A Spatially-Explicit Version Of Forman, Kieley Shannon Hurff

LSU Master's Theses

The mangrove forest gap dynamic model, FORMAN, was the first individual-based model (IBM) to simulate the long-term successional dynamics of three Caribbean mangrove species, Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle. Assumptions under the spatially implicit approach of gap dynamic models limit their application to small-scale simulations. An expanded, spatially-explicit version of FORMAN was developed to allow for simulations of larger spatial grids, through the inclusion of localized soil conditions and neighborhood-based light resource competition. This expanded model was used to investigate the influence of localized interactions and disturbances of varying size on forest dynamics. A data-model comparison using field …

Social Media Network Data Mining And Optimization, Neha Clare Jose

LSU Master's Theses

Many small social aid organizations could benefit from collaborating with other organizations on common causes, but may not have the necessary social relationships. We present a framework for a recommender system for the Louisiana Poverty Initiative that identifies member organizations with common causes and aims to forge connections between these organizations. Our framework employs a combination of graph and text analyses of the organizations' Facebook pages. We use NodeXL, a plugin to Microsoft Excel, to download the Facebook graph and to interface with SNAP, the Stanford Network Analysis Platform, for calculating network measurements. Our framework extends NodeXL with algorithms that …

Constructing The Search Template: Episodic And Semantic Influences On Categorical Template Formation, Juan D. Guevara Pinto

LSU Master's Theses

Search efficiency is usually improved by presenting observers with highly detailed target cues (e.g., pictures). However, in the absence of accurate target cues, observers must rely only on categorical information to find targets. Models of visual search suggest that guidance in a categorical search results from matching categorically-diagnostic target features in the search display to a top-down attentional set (i.e., the search template), but the mechanisms by which such attentional set is constructed have not been specified. The present investigation examined the influences of both semantic and episodic memory on search template formation. More precisely, the present study tested whether …

Evaluation Of Absorption And Uptake Of Soil- And Foliar-Applied Silicon In Rice And Its Accumulation Under Different Phosphorus Rates, Flávia Bastos Agostinho

LSU Master's Theses

Silicon (Si) fertilization has gained attention in rice (Oryza sativa) production. However, the common soil-applied sources are amended at high rates, whereas the efficacy of foliar Si application is yet to be proven. A series of pot experiments were conducted to (1) elucidate the effects of different Si sources on grain yield and Si accumulation of rice supplied with varying P rates, and 2) evaluate Si absorption and uptake by rice via foliar- and soil-application of Si fertilizers. First, three phosphorus (P) rates (0, 112, and 224 kg P ha-1) and three Si sources: two soil-applied (wollastonite and silicate slag) …

Living On The Edge: An Assessment Of The Habitat Use Of Waterbirds In Estuarine Wetlands Of Barataria Basin, La, Brett Ashley Patton

LSU Master's Theses

The wetlands of Louisiana are losing area at the rapid rate of 42.9 km2 yr-1 and the trend is expected to continue. This combined with expected sea-level rise will likely cause large shifts in vegetation and salinity regimes that will affect the wildlife species reliant on these ecosystems. Waterbirds serve as indicator species of ecosystem health in estuarine wetland habitats; therefore, these species are often the targets of wetland management goals in Louisiana. However, many proposed wetland restoration projects are focused primarily on social impacts with only a few specific waterbird species designated for management. The majority of these waterbird …

Character Studies Of Time: A Two Movement Work For Orchestra, Crystal Darcell Birdsong

LSU Master's Theses

The idea behind The Character Studies of Time: A Two Movement Work for Orchestra should be reminiscent of, and is inspired by the character pieces of Robert Schumann’s Carnival. Although the works of Robert Schumann are originally short piano solos, the spirit of the character piece and all that it entails could be found throughout The Character Studies of Time. This symphony does not follow a strict form of 19th century writing, although the elements of romanticism can be found throughout the piece. The “characters” as they relate to time are quite literally “night” and “day.” The individual titles are …

Effect Of Bitterness Blockers In Partial And Complete Replacement Of Sodium Chloride With Potassium Chloride On The Physicochemical And Sensory Characteristics Of Marinated Chicken Breast Fillets, Ana Gabriela Ocampo Arriaga

LSU Master's Theses

High sodium intake has negative health implications on hypertension and cardiovascular diseases. Brines used in chicken marination are composed of salt (NaCl), phosphates and seasonings. Potassium chloride (KCl) is the most common sodium replacer but its use is typically limited to less than 50% substitution due to its undesirable bitterness and metallic aftertaste. The objective of this study was to determine the effect of 5’ adenosine monophosphate (AMP) and glycine, as bitterness blockers, on physicochemical, sensory characteristics and purchase intent of sodium reduced chicken breast fillets. Chicken breast was injected with a 20% pick-up solution. Salt treatments (trts) were 50, …

An Architecture For Configuring An Efficient Scan Path For A Subset Of Elements, Arash Ashrafi

LSU Master's Theses

LaTeX4Web 1.4 OUTPUT Field Programmable Gate Arrays (FPGAs) have many modern applications. A feature of FPGAs is that they can be reconfigured to suit the computation. One such form of reconfiguration, called partial reconfiguration (PR), allows part of the chip to be altered. The smallest part that can be reconfigured is called a frame. To reconfigure a frame, a fixed number of configuration bits are input (typically from outside) to the frame. Thus PR involves (a) selecting a subset C Í S of k out of n frames to configure and (b) inputting the configuration bits for these k frames. …