Digital Commons Network^™

When Can Competition And Dispersal Lead To Checkerboard Distributions?, Tad Dallas, Brett A. Melbourne, Alan Hastings

Faculty Publications

© 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society Checkerboard distributions—mutually exclusive species co-occurrences—are a common observation in community ecology and biogeography. While the underlying causes of checkerboard distributions have remained elusive, a long-standing argument is that they are representative of strong competitive interactions and/or dispersal limitation. We explore this using a stochastic two-patch metacommunity model combined with an experimental two-patch system of competing Tribolium species, quantifying checkerboard distributions using the abundance-based index A st . We find that maintenance of checkerboard distributions is possible in a limited parameter space consisting of low dispersal rates, low …

Inward Rectifier Potassium (Kir) Channels Mediate Salivary Gland Function And Blood Feeding In The Lone Star Tick, Amblyomma Americanum, Zhilin Li, Kevin R. Macaluso, Lane D. Foil, Daniel R. Swale

Faculty Publications

© 2019 Li et al. Background Tick feeding causes extreme morbidity and mortality to humans through transmission of pathogens and causes severe economic losses to the agricultural industry by reducing livestock yield. Salivary gland secretions are essential for tick feeding and thus, reducing or preventing saliva secretions into the vertebrate host is likely to reduce feeding and hinder pathogen life cycles. Unfortunately, the membrane physiology of tick salivary glands is underexplored and this gap in knowledge limits the development of novel therapeutics for inducing cessation of tick feeding. Methodology We studied the influence of inward rectifier potassium (Kir) channel subtypes …

Effects Of Rare-Earth (R = Pr, Gd, Ho, Er) Doping On Magnetostructural Phase Transitions And Magnetocaloric Properties In Ni43-Xrxmn46sn11 Shape Memory Alloys, Anil Aryal, Sudip Pandey, Igor Dubenko, Dipanjan Mazumdar, Shane Stadler, Naushad Ali

Faculty Publications

A series of rare-earth-doped Ni43-xRxMn46Sn11 (x= 0, 1 and R = Pr, Gd, Ho, Er) alloys was fabricated by arc melting, and their structural, magnetic, and magnetocaloric properties were studied through room temperature X-ray diffraction (XRD), differential scanning calorimetry, and magnetization measurements. Analysis of XRD data reveal that the alloys crystallize in the cubic L21 austenite phase structure as the major phase with a small trace of martensitic phase (MP). The martensitic transition temperature (TM) shifts to consecutive higher temperatures with the substitution of Pr, Gd, Ho, and Er. A drastic shift in TM by 60 K relative to the …

Analysis Of The Angular Spectrum For Ultrashort Laser Pulses, Jeffrey M. Brown, Arnaud Couairon, Pavel Polynkin, Mette B. Gaarde

Faculty Publications

We present a practical diagnostic for quantifying changes to the supercontinuum spectrum of an ultrashort laser pulse undergoing nonlinear propagation. The method allows a connection to be made between a nonlinear physics phenomenon and the specific regions of the angular spectrum that it affects. We apply this method to investigate interference between third-harmonic generation and self-phase modulation.

An Experimental Study Of Fractional Wettability Effects On Gas Assisted Gravity Drainage (Gagd), Abdullah Abdulrahman A. Al-Tameemi

LSU Master's Theses

Utilizing the power of nature to solve engineering problems has been a time-honored tradition, for example, using the sunlight as a heat and light source. From this principle, the visionary idea of Gas Assisted Gravity Drainage (GAGD) came. The GAGD process utilizes the natural segregation phenomenon of fluids with different densities in order to produce oil efficiently and economically. Waterflooding processes typically do not recover more than 40% of the original oil in place (OOIP), leaving a vast amount of oil behind. A practical and well-planned enhanced oil recovery (EOR) method is needed. However, to plan a successful project, the …

Low-Density Static Granular Media Filter Bed Turbidity Removal Model, Matthew Louque

LSU Master's Theses

The scattering of light within a fluid, referred to as its turbidity, was investigated against the presence of suspended solids. A linear regression analysis was conduced against turbidity and the total count, combined surface area, and combined volume of the suspended particles for various surface water sources (lakes, rivers, indoor aquaculture systems). It was found that the total combined surface area of suspended particles had the best linear correlation to turbidity, with an adjusted R² of 81.79%. This correlation was integrated with a current theoretical model for predicting solids removal across a granular bed to yield an Integrated Turbidity …

Too Hot To Move: Temperatures During Transportation Might Reduce The Survival Of Salvinia Weevils (Coleoptera: Curculionidae), Lauren A. Cozad, Rodrigo Diaz, Christopher R. Mudge

Faculty Publications

© 2019 Florida Entomological Society. All rights reserved. The biological control agent, Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) (salvinia weevil), is being used for management of the highly invasive fern Salvinia molesta Mitchell (Salvinaceae) in Louisiana and Texas, USA. The weevils and plants are transported from the nurseries and rearing facilities to the field release sites in plastic totes. Despite the increased transport of weevil-infested plants during the warmer months, limited data exist on the impact of heat stress and survivability of adult C. salviniae. Therefore, research was conducted to determine temperatures inside totes during summer transport, and to …

Impact Of Psychological And Physical Stressors On The Exercise-Induced Immune Response In Collegiate Swimmers, Connor Alexander Kuremsky

LSU Master's Theses

Evidence suggests high-intensity exercise training increases incidence of upper respiratory infection in young-adult athletes (Spence et al. 2007). Collegiate athletes experience chronic stress, which has been shown to result in increased proportions of late-differentiated CD8+ T-cells of a dysfunctional phenotype (Bosch et al. 2009). However, many studies fail to consider possible moderators such as psychological stress and cytomegalovirus (CMV) infection. Purpose: To examine the impact of psychological stress, CMV infection, and exercise on proportions of early- and late-differentiated CD4+ and CD8+ T-cells in collegiate swimmers over a 7-month training period. Methods: Data were collected from NCAA …

The Genetic And Epigenetic Effects Of Pre-Treatment With The Small Molecule Inhibitors Chir99021, Pd0325901, And Nup0178 On Bovine Fetal Fibroblast Cells, Laura Whitney Coley

LSU Doctoral Dissertations

The ability to produce genetically superior livestock has established somatic cell nuclear transfer (SCNT) as an invaluable tool in commercial livestock production. Successful reprogramming of somatic cells towards pluripotency requires the epigenetic marks characteristic of the differentiated cell type first be erased in order to inactivate the somatic cell program and activate the embryonic program. Several small molecules have been shown to improve both the kinetics and efficiency of reprogramming. These chemical modifiers aid in overcoming the “roadblocks” encountered during the reprogramming process by inducing the necessary epigenetic modifications needed to silence the somatic cell genome and completely reactivate the …

Nitrogen Content In The Earth's Outer Core, Suraj K. Bajgain, Mainak Mookherjee, Rajdeep Dasgupta, Dipta B. Ghosh, Bijaya B. Karki

Faculty Publications

Using first principles molecular dynamic simulations, we explore the effects of nitrogen (N) on the density and sound velocity of liquid iron and evaluate its potential as a light element in the Earth's outer core. Our results suggest that Fe-N melt cannot simultaneously explain the density and seismic velocity of the Earth's outer core. Although ~2.0 wt.% N can explain the bulk sound velocity of the outer core, such N content only lowers the density of liquid Fe by ~3%. Matching both the velocity and density by the other light elements limits the N in the core to ≪2.0 wt.%. …

An Airlifted Tidal Mesocosm For Oil Degradation Studies, Daniel Christopher Alt

LSU Doctoral Dissertations

Mesocosms were constructed to allow scientists to isolate variables in a microtidal marsh environment, mimicking the natural conditions found in Terrebonne Bay. The control offered by these mesocosms is given by a process control system that takes user inputs and automates water movement. Twelve mesocosms were constructed, each holding 4.02 m³ (142 ft³) of marsh soil and 3.88 m³ (137 ft³) of water to give 3 experimental levels and a control, all in triplicate.

Each mesocosms that was constructed contained marsh plants in soil plugs 9 feet in diameter and 3 feet deep. These …

Diy In Early Live Electroacoustic Music: John Cage, Gordon Mumma, David Tudor, And The Migration Of Live Electronics From The Studio To Performance, Lindsey Elizabeth Hartman

LSU Doctoral Dissertations

This research examines early live electronic works by Gordon Mumma, David Tudor, and John Cage—three influential American experimental music composers who designed, built, and recontextualized electronics for live performance—and the Do-It-Yourself (DIY) aesthetic embodied by their instruments and the compositions written for them. This dissertation serves as a presentation of original research into the earliest composers of live electronic works and the necessary DIY approach used in building independent systems. Previous research on the DIY perspectives in music often touch on the grass-roots nature of contemporary electroacoustic systems but there is not yet research specific to the DIY approach taken …

High-Throughput Cultivation Of Bacterioplankton From The Gulf Of Mexico And Genomics Of The First Cultured Ld12 Representative, Michael Winslow Henson

LSU Doctoral Dissertations

Cultivation of microorganisms facilitates characterization of metabolism, interspecies dependencies, virus-host interactions, and other information necessary to resolve the functions and distribution of individual taxa. However, the metabolic and physiological capacities for the majority of microbes remains unresolved because of the lack of cultivated representatives for many groups limits our ability to test cultivation-independent observations. The Northern Gulf of Mexico offers a diversity of ecosystems under the continuous threat from natural and anthropogenic disturbances, yet little is known about its native bacterioplankton community. This dissertation sought to use high-throughput cultivation over three-years at six sites to isolate important coastal bacteria to …

The Interplay Among Tax Specialists, Corporate Tax Behavior, And Tax Accrual Quality, Pradeep Sapkota

LSU Doctoral Dissertations

Do tax specialists improve the accrual quality of tax accounts while simultaneously lowering effective tax rates (ETR)? Tax specialists are associated with lower ETRs. Since prior research finds that companies with lower ETRs are associated with lower financial reporting quality, companies that employ tax specialists may have lower tax accrual quality (TAQ). However, the potential for knowledge spillover and specialization effects suggests that tax specialists may simultaneously lower ETRs and improve TAQ. Thus, tax specialists can have an interesting influence on the joint effect with low ETRs on TAQ. I find that companies with lower ETRs are associated with lower …

Trophodynamics And Mercury Bioaccumulation In Reef And Open-Ocean Fishes From The Bahamas With A Focus On Two Teleost Predators, Oliver N. Shipley, Cheng Shiuan Lee, Nicholas S. Fisher, Georgiana Burruss, Michael G. Frisk, Edward J. Brooks, Zachary C. Zuckerman, Achim D. Herrmann, Daniel J. Madigan

Faculty Publications

© Inter-Research 2019. Identifying prey resource pools supporting fish biomass can elucidate trophic pathways of pollutant bioaccumulation. We used multiple chemical tracers (carbon [δ 13 C] and nitrogen [δ 15 N] stable isotopes and total mercury [THg]) to identify trophic pathways and measure contaminant loading in upper trophic level fishes residing at a reef and open-ocean interface near Eleuthera in the Exuma Sound, The Bahamas. We focused predominantly on the trophic pathways of mercury bioaccumulation in dolphinfish Coryphaena hippurus and wahoo Acanthocybium solandri, 2 commonly consumed pelagic sportfish in the region. Despite residing within close proximity to productive and extensive …

Investigations Into Aspergillus Flavus Infection Of Corn And Regulation Of Aflatoxin Production By Volatiles And Biocontrol Strains, Rebecca R. Sweany

LSU Doctoral Dissertations

Aspergillus flavus is an ascomycete fungus impacting agriculture, public and environmental health due to production of acutely-toxic, carcinogenic aflatoxins in oil seed crops, especially corn in Louisiana, and lung infections of immunocompromised patients resulting in a leading cause of AIDS patients’ deaths globally. The most effective aflatoxin mitigation strategy, biocontrol by atoxigenic A. flavus presents several concerns including: dissemination of a human pathogen, possible sexual reproduction and reliance on precise environmental conditions. Several aspects of A. flavus biology were investigated to potentially improve treatments. Studies investigated how genotypically diverse members within the A. flavus population interact with other population members …

A Critical Edition Of The Bachianas Brasileiras Nº2 For Piano And Cello By Heitor Villa-Lobos, Henrique Borges Gomes

LSU Doctoral Dissertations

The Brazilian composer Heitor Villa-Lobos (1887-1959) is one of the most prominent names in Twentieth century music. His compositional scope encompasses languages that often combine national elements of Brazilian music with traditions of European music. Villa-Lobos’s Bachianas Brasileiras is one of the most representative works that reflect the dialogue of those distinct worlds. With this series of distinct pieces, Villa-Lobos aimed to achieve musical universality through incorporating elements of Bach’s music with that of his own, which was already permeated by Brazilian popular traditions.

This research focusses on the four movements of the “reduced” version of the Bachianas Brasileiras no.2 …

Sensitivity Of Evacuation Time Estimation To Modeling Parameter Adjustment, Nelida Andreina Herrera

LSU Doctoral Dissertations

Over the past 40 years, a range of tools and techniques have been employed to assess traffic and travel conditions associated with evacuation events. These tools provide key insights into the temporal-spatial conditions of traffic during an evacuation. The representation of an evacuation in a traffic simulation model requires a number of assumptions about the input and modeling parameters needed to capture relevant aspects of such event. Therefore, a key aspect to ensure appropriate estimations of evacuation clearance times and overall efficacy of emergency planning is to better understand the influence and the importance that simulation modeling parameters have on …

Gumbo Yearbook, Class Of 2019, Louisiana State University And Agricultural And Mechanical College

Gumbo Yearbook

The Gumbo yearbook chronicles the entire academic year at LSU. In words and especially photos, the Gumbo shows the people, places, and events that make each year unique. In addition to formal portraits of schools and departments, the book contains hundreds of snapshots of students with their friends and dozens of pages showcasing organizations.

A 1-Dimensional Sympagic-Pelagic-Benthic Transport Model (Spbm): Coupled Simulation Of Ice, Water Column, And Sediment Biogeochemistry, Suitable For Arctic Applications, Shamil Yakubov, Philip Wallhead, Elizaveta Protsenko, Evgeniy Yakushev, Svetlana Pakhomova, Holger Brix

Faculty Publications

© 2019 by the authors. Marine biogeochemical processes can strongly interact with processes occurring in adjacent ice and sediments. This is especially likely in areas with shallow water and frequent ice cover, both of which are common in the Arctic. Modeling tools are therefore required to simulate coupled biogeochemical systems in ice, water, and sediment domains. We developed a 1D sympagic-pelagic-benthic transport model (SPBM) which uses input from physical model simulations to describe hydrodynamics and ice growth and modules from the Framework for Aquatic Biogeochemical Models (FABM) to construct a user-defined biogeochemical model. SPBM coupled with a biogeochemical model simulates …

Overexpressing The H-Protein Of The Glycine Cleavage System Increases Biomass Yield In Glasshouse And Field-Grown Transgenic Tobacco Plants, Patricia E. López-Calcagno, Stuart Fisk, Kenny L. Brown, Simon E. Bull, Paul F. South, Christine A. Raines

Faculty Publications

© 2018 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd. Photorespiration is essential for C3 plants, enabling oxygenic photosynthesis through the scavenging of 2-phosphoglycolate. Previous studies have demonstrated that overexpression of the L- and H-proteins of the photorespiratory glycine cleavage system results in an increase in photosynthesis and growth in Arabidopsis thaliana. Here, we present evidence that under controlled environment conditions an increase in biomass is evident in tobacco plants overexpressing the H-protein. Importantly, the work in this paper provides a clear demonstration of the …

Naringenin Promotes Thermogenic Gene Expression In Human White Adipose Tissue, Candida J. Rebello, Frank L. Greenway, Frank H. Lau, Yuan Lin, Jacqueline M. Stephens, William D. Johnson, Ann A. Coulter

Faculty Publications

© 2018 The Obesity Society Objective: Naringenin, a citrus flavonoid, prevents diet-induced weight gain and improves glucose and lipid metabolism in rodents. There is evidence that naringenin activates brown fat and increases energy expenditure in mice, but little is known about its effects in humans. The goal of this study was to examine the effects of naringenin on energy expenditure in adipose tissue. Methods: Human white adipocyte cultures (hADSC) and abdominal subcutaneous adipose tissue (pWAT) were treated with naringenin for 7 to 14 days. Expression (quantitative real-time polymerase chain reaction, immunoblotting) of candidate genes involved in thermogenesis and glucose metabolism …

Fabrication And Characterization Of Thiol-Triacrylate Polymer Via Michael Addition Reaction For Biomedical Applications, Anoosha Forghani, Leah Garber, Cong Chen, Fariborz Tavangarian, Timothy B. Tighe, Ram Devireddy, John A. Pojman, Daniel Hayes

Faculty Publications

© 2018 IOP Publishing Ltd. Thiol-acrylate polymers have therapeutic potential as biocompatible scaffolds for bone tissue regeneration. Synthesis of a novel cyto-compatible and biodegradable polymer composed of trimethylolpropane ethoxylate triacrylate-trimethylolpropane tris (3-mercaptopropionate) (TMPeTA-TMPTMP) using a simple amine-catalyzed Michael addition reaction is reported in this study. This study explores the impact of molecular weight and crosslink density on the cyto-compatibility of human adipose derived mesenchymal stem cells. Eight groups were prepared with two different average molecular weights of trimethylolpropane ethoxylate triacrylate (TMPeTA 692 and 912) and four different concentrations of diethylamine (DEA) as catalyst. The materials were physically characterized by mechanical …

Fluorescence-Based Ratiometric Nanosensor For Selective Imaging Of Cancer Cells, Isiah M. Warner, Kelsey E. Mcneel, Noureen Siraj, Nimisha Bhattarai

Faculty Publications

Herein, we report the synthesis and characterization of a nanosensor developed from a group of uniform materials based on organic salts (GUMBOS). This sensor is composed of three ionic species, namely, fluorescein, rhodamine B, and tetradecyltrihexyl phosphonium (P-66614) ions. Nanoparticles prepared from this three-component GUMBOS, termed nanoGUMBOS, exhibited increased fluorescence at two wavelengths with increases in pH values. The ratio of fluorescence emission corresponding to FL and RhB components of these nanoGUMBOS also changed with pH, allowing ratiometric analysis of pH through fluorescence measurements. Peak ratios were significantly different at pH 5 and pH 7, indicating potential applications of this …

Synthesis And Investigation Of Phthalocyanine-Biotin Conjugates, M. Graca H. Vicente, Elizabeth A. Okoth, Zehua Zhou, Benson Ongarora

Faculty Publications

An isothiocyanato-functionalized phthalocyanine (Pc) was synthesized in good yield from the corresponding amine-substituted Pc. This Pc reacted with ethanolamine, biotin hydrazine, and biotin diethylamine under mild conditions (room temperature in DMF or DMSO in the presence of TEA) to produce the corresponding thiourea products in 60-75% yields. All Pcs showed intense Q absorptions in DMF around 677 nm, emissions centered at 683 nm, and fluorescence quantum yields in the range 0.18-0.27. The Pcs were phototoxic to human carcinoma HEp2 cells (IC50 similar to 7 at 1.5 J/cm(2)) and localized in multiple organelles, including the lysosomes, Golgi and ER. One biotin-Pc …

Introduction To The Special Issue On “Economic Modeling Of Natural Resources For Sustainable Development”, Krishna P. Paudel

Faculty Publications

No abstract provided.

Mitofusin 2 Plays A Role In Oocyte And Follicle Development, And Is Required To Maintain Ovarian Follicular Reserve During Reproductive Aging, Man Zhang, Muhammed Burak Bener, Zongliang Jiang, Tianren Wang, Ecem Esencan, Richard Scott, Tamas Horvath, Emre Seli

Faculty Publications

© Zhang et al. Mitochondria change their shape through fusion and fission in order to adapt to their metabolic milieu. Mitofusin-2 (MFN2) is a key regulatory protein in this process, mediating mitochondrial fusion and interaction with endoplasmic reticulum. Targeted deletion of Mfn2 in oocytes resulted in mitochondrial dysfunction and female subfertility associated with impaired oocyte maturation and follicle development. Oocytes lacking MFN2 showed shortened telomeres and increased apoptosis, resulting in compromised oocyte quality and accelerated follicular depletion, consistent with a reproductive aging phenotype.

Louisiana Agriculture Winter, 2019, Lsu Agcenter

Louisiana Agriculture

No abstract provided.

Spatiotemporal Coupling Of Attosecond Pulses, Hampus Wikmark, Chen Guo, Jan Vogelsang, Peter W. Smorenburg, Hélène Coudert-Alteirac, Jan Lahl, Jasper Peschel, Piotr Rudawski, Hugo Dacasa, Stefanos Carlström, Sylvain Maclot, Mette B. Gaarde, Per Johnsson, Cord L. Arnold, Anne L'Huillier

Faculty Publications

The shortest light pulses produced to date are of the order of a few tens of attoseconds, with central frequencies in the extreme UV range and bandwidths exceeding tens of electronvolts. They are often produced as a train of pulses separated by half the driving laser period, leading in the frequency domain to a spectrum of high, odd-order harmonics. As light pulses become shorter and more spectrally wide, the widely used approximation consisting of writing the optical waveform as a product of temporal and spatial amplitudes does not apply anymore. Here, we investigate the interplay of temporal and spatial properties …

Children’S Environmental Health In South And Southeast Asia: Networking For Better Child Health Outcomes, Peter D. Sly, Brittany Trottier, David Carpenter, Ubon Cha’On, Stephania Cormier, Betsy Galluzzo, Samayita Ghosh, Fiona Goldizen, Michelle Heacock, Paul Jagals, Hari Datt Joshi, Prachi Kathuria, Le Thai Ha, Melina S. Magsumbol, Panida Navasumrit, Poornima Prabhakaran, Banalata Sen, Chris Skelly, Inoka Suraweera, Sathiarany Vong, Chador Wangdi, William A. Suk

Faculty Publications

© 2019 The Author(s). Children are particularly vulnerable to environmental hazards because they receive higher doses of pollutants in any given environment and often do not have equitable access to social protection mechanisms such as environmental and health care services. The World Health Organization established a global network of collaborating centres that address children’s environmental health (CEH). The network developed a focus on low- and middle-income countries (LMICs) and is broadening its reach by conducting regional workshops for CEH. Objective: This paper reports on the outcomes of a workshop held in conjunction with the 17th International Conference (November 2017) of …