Digital Commons Network^™

The Behavior Of Metropolis-Coupled Markov Chains When Sampling Rugged Phylogenetic Distributions, Jeremy M. Brown, Robert C. Thomson

Faculty Publications

© The Author(s) 2018. Bayesian phylogenetic inference relies on the use of Markov chain Monte Carlo (MCMC) to provide numerical approximations of high-dimensional integrals and estimate posterior probabilities. However, MCMC performs poorly when posteriors are very rugged (i.e., regions of high posterior density are separated by regions of low posterior density). One technique that has become popular for improving numerical estimates from MCMC when distributions are rugged is Metropolis coupling (MC3). InMC3, additional chains are employed to sample flattened transformations of the posterior and improve mixing. Here, we highlight several underappreciated behaviors of MC3. Notably, estimated posterior probabilities may be …

Liquid Sucrose Consumption Promotes Obesity And Impairs Glucose Tolerance Without Altering Circulating Insulin Levels, Susan J. Burke, Heidi M. Batdorf, Thomas M. Martin, David H. Burk, Robert C. Noland, Christopher R. Cooley, Michael D. Karlstad, William D. Johnson, J. Jason Collier

Faculty Publications

© 2018 The Obesity Society Objective: Multiple factors contribute to the rising rates of obesity and to difficulties in weight reduction that exist in the worldwide population. Caloric intake via sugar-sweetened beverages may be influential. This study tested the hypothesis that liquid sucrose intake promotes obesity by increasing serum insulin levels and tissue lipid accumulation. Methods: C57BL/6J mice were given 30% sucrose in liquid form. Changes in weight gain, body composition, energy expenditure (EE), and tissue lipid content were measured. Results: Mice drinking sucrose gained more total body mass (TBM), had greater fat mass, and displayed impaired glucose tolerance relative …

Synthesis And In Vitro Pdt Evaluation Of New Porphyrins Containing Meso-Epoxymethylaryl Cationic Groups, Jaqueline Carneiro, Alan Gonçalves, Zehua Zhou, Kaitlin E. Griffin, Nichole E.M. Kaufman, Maria Da Graça Henriques Vicente

Faculty Publications

© 2018 Wiley Periodicals, Inc. Objectives: Photodynamic therapy (PDT) is an effective cancer treatment that uses photosensitizers, light, and oxygen to destroy malignant cells. Porphyrins, and in particular the cationic derivatives, are the most investigated photosensitizers for PDT. In this context, it is important to study new methodologies to develop efficient cationic photosensitizers for use in PDT. Materials and Methods: New porphyrins bearing cationic epoxymethylaryl groups were synthesized and characterized. Their cellular uptake, intracellular localization, and phototoxicity were evaluated in human HEp2 cells, and compared with their methylated analogs. Results: All cationic porphyrins were efficient generators of singlet oxygen, with …

Inhibition Of Endocytosis Suppresses The Nitric Oxide-Dependent Release Of Cl- In Retinal Amacrine Cells, Vernon K. Dunn, Evanna Gleason

Faculty Publications

© 2018 Dunn, Gleason. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Our lab has previously shown that nitric oxide (NO) can alter the synaptic response properties of amacrine cells by releasing Cl- from internal acidic compartments. This alteration in the Cl- gradient brings about a positive shift in the reversal potential of the GABA-gated current, which can convert inhibitory synapses into excitatory synapses. Recently, we have shown that the cystic fibrosis transmembrane regulator …

Pheromone-Trap Monitoring System For Pea Leaf Weevil, Sitona Lineatus: Effects Of Trap Type, Lure Type And Trap Placement Within Fields, Gadi V.P. Reddy, Govinda Shrestha, Debra A. Miller, A. Cameron Oehlschlager

Faculty Publications

The pea leaf weevil, Sitona lineatus, is an important pest of field peas and faba beans worldwide. Present sampling techniques that rely on detection of adult feeding damage are labor intensive, time consuming and require repeated sampling. Semiochemical-based pest monitoring systems could improve pea leaf weevil management. This study, which was conducted in the Golden Triangle region of Montana, tested several factors that potentially might affect capture rates of pheromone-baited traps, including trap and lure type and trap placement. Pheromone-baited pitfall and ramp traps caught significantly more adults than ground or delta traps, in all study areas. Pitfall traps baited …

Management Of Insect Pests In The Production And Storage Of Minor Pulses, Ruparao T. Gahukar, Gadi V.P. Reddy

Faculty Publications

Minor pulses are cultivated on a small scale by economically poor farming communities for subsistence food. Currently, these crops are under-utilized or neglected, although they are reasonable sources of protein and can increase food security in rural areas. Research and development is underway to improve the grain quality and increase the productivity of these crops, both of which are negatively impacted by insect pest damage. Synthetic pesticides have proven to be the most effective control agents against all pests of minor pulses which include sap sucking insects. However, considering the drawbacks of pesticide residues in the grain, environmental pollution, and …

Estimating Epidemiological Parameters Of A Stochastic Differential Model Of Hiv Dynamics Using Hierarchical Bayesian Statistics, Renee Dale, Bei Bei Guo

Faculty Publications

Current estimates of the HIV epidemic indicate a decrease in the incidence of the disease in the undiagnosed subpopulation over the past 10 years. However, a lack of access to care has not been considered when modeling the population. Populations at high risk for contracting HIV are twice as likely to lack access to reliable medical care. In this paper, we consider three contributors to the HIV population dynamics: at-risk population exhaustion, lack of access to care, and usage of anti-retroviral therapy (ART) by diagnosed individuals. An extant problem in the mathematical study of this system is deriving parameter estimates …

Natively Oxidized Amino Acid Residues In The Spinach Cytochrome B6 F Complex, Ryan M. Taylor, Larry Sallans, Laurie K. Frankel, Terry M. Bricker

Faculty Publications

© 2018, Springer Science+Business Media B.V., part of Springer Nature. The cytochrome b6f complex of oxygenic photosynthesis produces substantial levels of reactive oxygen species (ROS). It has been observed that the ROS production rate by b6f is 10–20 fold higher than that observed for the analogous respiratory cytochrome bc1 complex. The types of ROS produced (O2•−, 1O2, and, possibly, H2O2) and the site(s) of ROS production within the b6f complex have been the subject of some debate. Proposed sources of ROS have included the heme bp, PQp•− (possible sources for O2•−), the Rieske iron–sulfur cluster (possible source of O2•− and/or …

An Evaluation Of College Student Attitudes Toward Gay Adoption, Cassandra Chaney Phd, Le'brian Patrick

Faculty Publications

Given the increasing debate regarding same-sex marriage and same-sex adoption, few studies to date have examined college student attitudes regarding this topic. This qualitative study explores the sentiments of 31 college students from a large university in the southern region of the country towards gay adoption before and after viewing the documentary We Are Dad (2005). The study allowed students to provide their level of agreement or disagreement with the statements provided by respondents on a public blog site who debated both sides of this issue. In addition, students responded to the following two questions during two points in time: …

Woody Plants Optimise Stomatal Behaviour Relative To Hydraulic Risk, William R.L. Anderegg, Adam Wolf, Adriana Arango-Velez, Brendan Choat, Daniel J. Chmura, Steven Jansen, Thomas Kolb, Shan Li, Frederick C. Meinzer, Pilar Pita, Víctor Resco De Dios, John S. Sperry, Brett T. Wolfe, Stephen Pacala

Faculty Publications

Stomatal response to environmental conditions forms the backbone of all ecosystem and carbon cycle models, but is largely based on empirical relationships. Evolutionary theories of stomatal behaviour are critical for guarding against prediction errors of empirical models under future climates. Longstanding theory holds that stomata maximise fitness by acting to maintain constant marginal water use efficiency over a given time horizon, but a recent evolutionary theory proposes that stomata instead maximise carbon gain minus carbon costs/risk of hydraulic damage. Using data from 34 species that span global forest biomes, we find that the recent carbon-maximisation optimisation theory is widely supported, …

Matrix And Area Effects On The Nutritional Condition Of Understory Birds In Amazonian Rainforest Fragments, Angélica Hernández-Palma, Philip C. Stouffer

Faculty Publications

Forest fragmentation, a result of deforestation, not only decreases the amount of habitat available for wildlife, but also increases the isolation of the remaining fragments and the area of edges surrounding them. Also, deforestation often leads to the creation of a dynamic regenerating matrix where cleared land is subsequently abandoned. Here we examine the effects of fragmentation and landscape change on the nutritional condition of Amazonian rainforest birds at the Biological Dynamics of Forest Fragments Project, near Manaus, Brazil. We analyzed ptilochronology-based measurements of feather growth rate in 12 species living in fragments within a dynamic landscape over 21 years. …

What Can Mixed-Species Flock Movement Tell Us About The Value Of Amazonian Secondary Forests? Insights From Spatial Behavior, Karl Mokross, Jonathan R. Potts, Cameron L. Rutt, Philip C. Stouffer

Faculty Publications

The value of secondary forest for rain forest species remains an important question for conservation in the 21st century. Here, we describe the spatial behavior of understory mixed-species flocks in a heterogeneous landscape in central Amazonia. Understory mixed-species flocks represent a diverse, highly organized component of the rich Amazonian avifauna. We recorded movements within 26 flock home ranges in primary forest, secondary forest, interfaces between forest types, and forest fragments. We describe frequency and movement orientation in relation to forest edges, movement patterns and proportion of use between secondary and primary forest, the relation between home range sizes and vegetation …

Endocannabinoid Metabolome Of Human Breast Milk, Adriana V. Gaitan Espinoza

LSU Doctoral Dissertations

Human breast milk (HBM) is an extremely complex yet fascinating biofluid tailored to meet an infant’s nutritional requirements for development. Amongst the nutrients present in HBM, the long-chain polyunsaturated fatty acids (LCPUFAs) are of high importance due to the pivotal role they play in infant cognitive and visual development, and growth. In addition, the LCPUFAs are precursors to endocannabinoids (EC) which are endogenous lipid mediators. EC exert metabolic responses including appetite and food intake regulation, and they have been identified to play a role in establishing the suckling response of the newborn that is needed to nurse. Thus, we aimed …

Exploring The Role Of Rna Polymerase Iii Complex Assembly On Ribosomal Dna Silencing In Saccharomyces Cerevisiae, Kyle Thomas Kern

LSU Doctoral Dissertations

The yeast rDNA region is host to a number of transcriptional regulatory elements, which work in conjunction to generate essential RNA subunits of ribosomes, as well as protecting the region from DNA damage. The role of RNA polymerase III complex binding at the 5S gene on rDNA silencing in the NTS2 region was investigated, both by use of a TY1:MET15 reporter insert and a MET15 gene integration at an endogenous SphI site. It was discovered that Pol III complexes do have an effect on reporter expression in the NTS2 region, though the specific effect was different based on the method …

Risk Assessment Of Fall Armyworm Resistance To Transgenic Corn Containing Single Or Pyramided Bacillus Thuringiensis Genes, Ying Niu

LSU Doctoral Dissertations

The fall armyworm, Spodoptera frugiperda (J.E. Smith), is a target pest of Bacillus thuringiensis (Bt) crops in North and South America. However, after more than two decades of the intense use of Bt crop technology, S. frugiperda has developed resistance to Bt corn in several countries. The objectives of this study were: 1) to characterize the inheritance and fitness costs of Cry1A.105 resistance in S. frugiperda; 2) to evaluate larval survival and plant injury of Cry1A.105-susceptibile, -resistant, and -heterozygous S. frugiperda populations on transgenic corn plants containing single or pyramided Bt genes; 3) to estimate the frequency of Cry2Ab2 …

Determining The Drivers Of Anti-Tropical Distributions Across The Fish Tree Of Life, William Benton Ludt

LSU Doctoral Dissertations

Anti-tropical distributions are those where populations of a single species, or multiple closely related taxa, are distributed outside of, and on opposing sides of, the tropics. These latitudinally disjunct distributions have been noted for over a century. Despite this long history of interest, little has been concluded regarding the actual mechanisms that drive this pattern, with several prominent hypotheses competing with one another in the literature. Here I review the proposed drivers of anti-tropicality, and subsequently test them using fishes with a variety of life history and taxonomic differences. This includes (1) a temperately restricted family with anti-tropical distributions – …

Evaluation Of Dopaminergic And Antidopaminergic Agents For Use In Equine Metabolic Physiology, Nicole Arana Valencia

LSU Doctoral Dissertations

A series of experiments studied the effects and practical applications of dopaminergic and antidopaminergic compounds in equine metabolic physiology. The first experiment was performed to assess the long-term effects of repeated cabergoline injections (every 10 days for a total of seven injections) on prolactin and α-melanocyte stimulating hormone concentrations in insulin insensitive mares. Additionally, the experiment also evaluated the use of cabergoline for improving insulin sensitivity. Plasma prolactin and α-melanocyte stimulating hormone concentrations were suppressed throughout the duration of the experiment even when the mares were challenged with a low-dose dopamine antagonist, sulpiride, the day previous to their subsequent cabergoline …

Impact Of Temperature, Plant Species, And Sorghum Cultivar On The Population Dynamics Of Melanaphis Sacchari, Monique Ferreira De Souza

LSU Doctoral Dissertations

Sugarcane aphid, Melanaphis sacchari Zehner, is now widely established in sorghum, Sorghum bicolor L., production areas of the United States and is an important economic pest. However, detailed studies of temperature, host range and plant resistance effects on the biology and population parameters of the M. sacchari biotype responsible for the sorghum outbreak in the United States have not been performed previously. Therefore, the present study aimed to investigate: 1) How temperatures affect M. sacchari 2) M. sacchari interaction with host plants 3) M. sacchari interaction with sorghum genotypes. The response of M. sacchari to six different constant temperatures (15, …

Endocytosis And The Nitric Oxide-Dependent Release Of Chloride, Vernon K. Dunn Jr

LSU Doctoral Dissertations

Understanding the regulation of retinal synapses is a key step in elucidating the processing of information in the retina. Our lab has previously shown that nitric oxide (NO) can alter the synaptic response properties of amacrine cells by releasing Cl- from internal acidic compartments. This alteration in the Cl- gradient brings about a positive shift in the reversal potential of the GABA-gated current, which can convert inhibitory synapses into excitatory synapses. Recently, we have shown that the cystic fibrosis transmembrane regulator (CFTR) Cl- channel is involved in the Cl- release. Here, we test the hypothesis that (acidic) synaptic vesicles are …

Computational Analysis Of Papionini Evolution Using Alu Insertions, Vallmer Edward Jordan Ii

LSU Doctoral Dissertations

Alu elements are primate specific retrotransposons that have remained active throughout the course of primate evolution. As a result of this sustained mobilization. Alu elements are present in greater copy number in primate genomes than any other transposable element. An average of over one million Alu elements has been identified in every sequenced haplorrhine genome to date. These characteristics qualify Alu elements as ideal characters for studying evolutionary relationship among primates.

The increasing availability of whole genome sequencing data presents novel challenges and opportunities for comparative genomic analyses. Genomic data is now publicly available for most primate species. Such an …

Healthcare Utilization & Health Behaviors Among Older Adults: The Role Of Insurance, Jennifer Rose Geiger

LSU Doctoral Dissertations

As the population of older adults in the U.S. continues its exponential growth, so too will the need for high-quality health and preventive services. Despite the widely acknowledged need for proactive solutions to the coming public health challenges for this rapidly expanding age cohort, healthcare providers and social work practitioners continue to lack the proper education training to serve the needs of older adults. Furthermore, these allied health professionals also frequently engage in ageist behaviors across care settings that also often employ institutionally ageist policies and procedures. As a result, older adults may be particularly at risk of negative health …

Demonstration Of The Gas Assisted Gravity Drainage (Gagd) Process In Carbonate Rocks., Alok Jiteshkumar Shah

LSU Master's Theses

The Gas Assisted Gravity Drainage (GAGD) process was developed and patented by Dr. Rao at LSU in the early 2000s. The process involves the use of several existing or new vertical injection wells to inject gas and use the natural segregation of reservoir fluids from the density difference and the gravitational forces to displace the trapped oil and mobilize the oil downwards to be produced by a horizontal producing well. The GAGD process can be implemented as a secondary or tertiary oil recovery method. Several physical model experiments have been conducted to demonstrate the effectiveness of the GAGD process for …

Purifying Selection In The Toll-Like Receptors Of Song Sparrows Melospiza Melodia, Martha J. Nelson-Flower, Ryan R. Germain, Elizabeth A. Macdougall-Shackleton, Sabrina S. Taylor, Peter Arcese

Faculty Publications

Variation in immune gene sequences is known to influence resistance to infectious diseases and parasites, and hence survival and mate choice, across animal taxa. Toll-like receptors (TLRs) comprise one essential gene family in the vertebrate innate immune system and recognize evolutionarily conserved structures from all major microorganism classes. However, the causes and consequences of TLR variation in passerine birds remain largely unexplored. We examined 7 TLR genes in song sparrows (Melospiza melodia), a species that is studied across North America. We then examined sequences from 4 unduplicated TLRs (TLR1LB, TLR3, TLR4, and TLR15) from birds in 2 parts of the …

Identification Of Genomic Regions Controlling Leaf Scald Resistance In Sugarcane Using A Bi-Parental Mapping Population And Selective Genotyping By Sequencing, Andres F. Gutierrez, Jeffrey W. Hoy, Collins A. Kimbeng, Niranjan Baisakh

Faculty Publications

Leaf scald, caused by Xanthomonas albilineans, is a major sugarcane disease worldwide. The disease is managed primarily with resistant cultivars obtained through classical breeding. However, erratic symptom expression hinders the reliability and reproducibility of selection for resistance. The development and use of molecular markers associated with incompatible/compatible reactions could overcome this limitation. The aim of the present work was to find leaf scald resistance-associated molecular markers in sugarcane to facilitate marker-assisted breeding. A genetic linkage map was constructed by selective genotyping of 89 pseudo F2 progenies of a cross between LCP 85-384 (resistant) and L 99-226 (susceptible) using 1,948 single …

Susceptibility Of Field-Collected Pupations Of The Corn Earworm, Helicoverpa Zea (Boddie) (Lepidoptera: Noctuidae) From Three Southern States Of The U.S. To Cry1a.105 And Cry2ab2 Proteins, Gagandeep Kaur

LSU Master's Theses

The corn earworm (CEW), Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), is a major target pest of pyramided Bt corn and Bt cotton in the U.S. In 2016 and 2017, notable corn ear damage and larval survival of CEW were observed on pyramided Cry1A.105/Cry2Ab2 corn in some fields in northeast Louisiana. The objectives of this study were 1) to determine if the ear damage and larval survival observed in the area were due to resistance development to the Bt proteins in the plants, and 2) if resistance had occurred, to determine the approximate distributions of the resistance in the southern region of …

Backstepping And Sequential Predictors For Control Systems, Jerome Avery Weston

LSU Doctoral Dissertations

We provide new methods in mathematical control theory for two significant classes of control systems with time delays, based on backstepping and sequential prediction. Our bounded backstepping results ensure global asymptotic stability for partially linear systems with an arbitrarily large number of integrators. We also build sequential predictors for time-varying linear systems with time-varying delays in the control, sampling in the control, and time-varying measurement delays. Our bounded backstepping results are novel because of their use of converging-input-converging-state conditions, which make it possible to solve feedback stabilization problems under input delays and under boundedness conditions on the feedback control. Our …

Factors Affecting Spatial Differences In Health Outcomes, Kwadwo Poku-Agyemang

LSU Master's Theses

This study sought to establish the impact of the disparities between Metropolitan, Micropolitan and Non-Core communities on life expectancy. The study also assesses the impact of individual behavioral choices and certain social variables and county level policies one the life expectancy in a county.

A simple mean comparison analysis is employed to establish the differences in life expectancy across the various levels of the urban hierarchy in 1,553 counties in the United States. An ordinary least squares model is used to tease out the relationship between specific individual choice factors; smoking habits, obesity and exercise habits and socio-economic factors; medicare …

New Platinum(Ii) And Rhenium(I) Complexes Of "Linear" Chelate Ligands Terminated With Pyridyl Or Imidazolyl N-Donor Groups, Himali Kokila Ranasinghe Pilana Vithanage

LSU Doctoral Dissertations

The overall goal of this dissertation research is to design, synthesize, and study new Pt(II) and Re(I) complexes relevant to biomedical applications. One of the projects involves the assessment of the interactions of bulky tridentate carrier ligands with a bound guanine nucleobase derivative (G) in platinum complexes, with a goal of developing chemistry potentially relevant to active anti-cancer Pt drugs. In another project, the fac-[Re^I(CO)₃]⁺ core is used to prepare novel Re(I) complexes with the purpose of developing new linking chemistry relevant to ^99mTc and ¹⁸⁷Re radiopharmaceuticals. This research explores …

Phosphorus Fluxes From Three Coastalwatersheds Under Varied Agriculture Intensities To The Northern Gulf Of Mexico, Songjie He, Y. Jun Xu

Faculty Publications

This study aims to evaluate recent total phosphorus (TP) and dissolved inorganic phosphorus (DIP) transport from three coastal rivers-the Calcasieu, Mermentau, and Vermilion Rivers-that drain watersheds with varied agriculture intensities (21%, 67%, and 61%, respectively) into the northern Gulf of Mexico, one of the world's largest summer hypoxic zones. The study also examined the spatial trends of TP and DIP from freshwater to saltwater along an 88-km estuarine reach with salinity increasing from 0.02 to 29.50. The results showed that from 1990-2009 to 2010-2017, the TP fluxes for one of the agriculture-intensive rivers increased while no significant change was found …

Effects Of Oil On Mollusk And Crustacean Populations, Behavior, And Predator-Prey Interactions, Elizabeth Marie Robinson

LSU Doctoral Dissertations

The Deepwater Horizon blowout and oil spill in April 2010 released ~5 million barrels of oil into the Gulf of Mexico. Approximately 1,773 km of shoreline was oiled along the northern Gulf of Mexico coast, and ~60% of the oiling ended up on Louisiana salt marsh habitat. The objective of this dissertation was to examine the effects of DWH oil on predator-prey relationships between blue crabs and periwinkle snails, as well as mollusk and blue crab population structure. A broad spatial-temporal field study in Barataria and Terrebonne Bays was used to examine the legacy of oil on five species of …