Digital Commons Network^™

Evaluation Of Cell Concentration And Viability By Impedance Spectroscopy On Microfluidic Devices, Jason Eades

LSU Master's Theses

This document describes two distinct platforms that implement electrochemical impedance spectroscopy (EIS) within microfluidic devices for rapid, label-free cell analysis. Each study provides proof-of-concept evaluations of these devices for cell counting and viability analysis applications to mitigate some of the challenges associated with conventional methods. Chapter one includes background information on each version of EIS selected and motivations for the studies conducted. Chapter two describes the design and fabrication of a modular, reusable microfluidic device. Additionally, the methodology for and results from the application of this platform for the measurement of zebrafish sperm cell concentrations are presented. Chapter three describes …

Investigating Local Adaptation To Hypoxia Stress In The Eastern Oyster Through Comparative Transcriptomics, Heather Nichole Smith

LSU Master's Theses

Climate change represents one of the most important challenges to biodiversity, therefore it is important to understand the mechanisms that allow species to respond to rapid environmental change. Here, we compared two populations of eastern oysters, Crassostrea virginica, from the Gulf of Mexico to study the mechanisms underlying hypoxia tolerance. Using a common garden experiment and comparative transcriptomics, we identified sets of genes involved in the hypoxia response and found differences in both the timing and baseline expression of hypoxia-responsive genes between tolerant and sensitive populations, consistent with a scenario of local adaptation. These genes include the signaling transcription factor …

Evaluation Of Cool-Season Annuals Effect On Soil Health In Warm-Season Perennial Pastures In Southestern Us., Paola C. Muela Negrete

LSU Master's Theses

Perennial grass crops represent approximately 8 million hectares of the land area of the humid lower southeastern United States. These forage crops receive high rates of fertilizer, especially nitrogen (N), and near monoculture remains have often been treated with repeated applications of herbicides. Pasture management is crucial to improve soil properties in pasturelands. Common pasture management practices include introducing cool-season multispecies in warm-season pasture systems and forage harvest frequency of pasture systems. It is known that cool-season multispecies in warm-season pasture systems ensure cattle feeding during winter season and have beneficial effects on soil microbial biomass, soil organic matter (SOM), …

The Evolution Of Dietary Adaptations In Small Mammals: From Muscles To Microbes, Mark Thomas Swanson

LSU Doctoral Dissertations

My dissertation provides critical insights on the pattern and process of evolution in front-end and back-end dietary adaptations of mammals. I found that the position of the rodent masseter muscle, a complex front-end adaptation that improves the efficiency of mechanical digestion, has convergently evolved numerous times, suggesting that selective pressure for this adaptation has been strong. For back-end adaptations, I found gut bacterial taxa that likely aid in chemical digestion of food have predictable associations with host diet across host species in natural environments. To detect patterns in gut microbial community structure that are related to host factors such as …

Effects Of Wetland Management And Associated Abiotic Factors On Rare Plant Communities Of Spring-Fed Arid Wetlands, Antonio Cantu De Leija

LSU Master's Theses

Spring-fed arid wetlands support high biological productivity and are hotspots for endemism and distribution of rare plants, making them areas of high conservation value. These systems are driven by complex interactions among groundwater discharge and the geomorphic and climatic features of the setting, which provide gradients of edaphic conditions, particularly soil moisture and salinity that influence the presence and abundance of rare plant communities. However, spring-fed arid wetlands are at particular risk of increases in salinity and drier hydrological regimes due to anthropogenic activities. Such alterations to abiotic conditions may jeopardize the distribution and abundance of rare plants by exceeding …

Optimization Of Mechanical Properties At The Infarct Border Zone, Kaushik Sunder

LSU Master's Theses

A myocardial infarction (MI) occurs every 39 seconds in the United States. As of 2016, an estimated 550,000 new and 200,000 recurrent episodes of myocardial infarction (MI) occur each year in the United States was. Infarction is often distinguished by a considerable decrease in wall thickness and an increase in heart size or left ventricular volume. This behavior happens when there is a prolonged lack of blood flow, usually due to damage or clotting, which causes cardiomyocytes to die (CMs). The development of non-contractile infarct scarring is the primary pathophysiology of MI. While the infarct scar prevents myocardial rupture during …

Investigating The Genomic Distribution Of Phylogenetic Signal With Cloudforest, Reid Wagner, Benjamin S. Toups, Zhifeng Deng, Kyle A. Gallivan, Jeremy M. Brown, James C. Wilgenbusch

Faculty Publications

A central focus of evolutionary biology is inferring the historical relationships among species and using this context to learn about how evolution has shaped diverse organisms these historical relationships are represented by phylogenetic trees, and the methods used to infer these trees have been an active area of research for several decades. Despite this attention, phylogenetic workflows have changed little, even though extraordinary advances have occurred in the scale and pace at which genomic data have been collected in the past 20 years. Modern phylogenomic datasets have also raised fascinating new questions. Why do different parts of a genome often …

Understanding Potassium Toxicity Stress Responses Of The Extremophyte Schrenkiella Parvula Using Systems Biology Approaches, Pramod Pantha

LSU Doctoral Dissertations

Schrenkiella parvula is an extremophyte model closely related to Arabidopsis thaliana and Brassica crops. Its natural habitat includes shores of saline lakes in the Irano-Turanian region. It has adapted to grow in soils rich in multiple salts including Na⁺ and K⁺. I have investigated the genetic basis for high K⁺ tolerance in plants using S. parvula as a stress tolerant model compared to the premier plant model, Arabidopsis thaliana which is highly sensitive to salt stresses using physiological, ionomic, transcriptomic, and metabolomic approaches. Under high K⁺ stress, root system architecture changes significantly compared to control …

Examining Intraindividual Variability As A Predictor Of Cognitive And Functional Decline In Older Adulthood, Alyssa N. De Vito

LSU Doctoral Dissertations

Intraindividual variability (IIV) has recently emerged as a promising early indicator of future cognitive decline (Haynes et al., 2017). However, the literature is currently limited in that the majority of studies have only examined IIV in one cognitive domain: reaction time. Explorations into the relationship between IIV and functional status are also sparse, with only one recent study exploring this relationship (Schmitter-Edgecombe et al., 2020). The present study aimed to address gaps in the literature by examining IIV in differing cognitive domains to determine which measure(s) were the best predictors of cognitive and functional status at baseline as well as …

#Blackgirlmathmagic: A Mixed Methods Study Examining African American Girls In Standardized Mathematicstesting, Rakeema Thomas Toussaint

LSU Doctoral Dissertations

Black women have been making successful strides in mathematics for decades; however, they continue to be underrepresented in mathematics and other STEM fields. According to Young et al. (2017), Black girls and women perform lower in mathematics than all other racial gender groups except for Black males. Considering the stakes for Black girls and women in mathematics, this study sought to address this group's challenges early in their secondary education experiences, focusing on standardized testing.

The purpose of this explanatory-sequential mixed-methods study was to determine how different mathematics item types impacted the performance of African American girls, especially multiple-select multiple-choice …

Seasonal Variation In The Feeding Ecology Of Yellowfin Tuna (Thunnus Albacares) From The Northern Gulf Of Mexico, Mitchell Shay Lovell

LSU Master's Theses

Highly migratory fishes (e.g., tunas, billfishes, and sharks) play a significant role in the structure and function of open-ocean ecosystems and a better understanding of the food web dynamics that support their populations is essential to improve management and conservation. Here, I use complementary approaches (stomach contents, DNA barcoding, & stable isotopes) to examine seasonal variability in the feeding ecology of sub-adult (70 – 100 cm; n = 371) and adult (100 – 160 cm; n = 206) yellowfin tuna (Thunnus albacares) from the northern Gulf of Mexico over a one-year period (April 2019 – March 2020). Stomach …

Late Embryogenesis Abundant Proteins And Mitochondrial Membranes From An Animal Extremophile: Insights Into Severe Water Stress, John Marcus Anderson

LSU Doctoral Dissertations

This dissertation focuses on two major topics germane to mechanisms by which animals tolerate extreme water stress. First, the impact of transgenic expression of late embryogenesis abundant proteins (LEA) on water stress tolerance of the fruit fly Drosophila melanogaster was investigated. The overall aim was to extend current understanding of the protective properties of LEA proteins documented with isolated cells to a desiccation-sensitive organism during exposure to drying and hyperosmotic stress. Four lines of D. melanogaster were created that expressed transgenes encoding selected LEA proteins originally identified in embryos of the extremophile Artemia franciscana. After 80% tissue water loss, …

Covid-19 Pandemic: A Mixed-Methods Study Investigation Of A Health Science System Faculty's Adaptations To An Online (Non-Traditional) Teaching Environment For Health Professional Students, Daryl Philip Lofaso

LSU Doctoral Dissertations

The purpose of this mixed method study was to explore the transition to an online educational platform for future health professional students at a southern health sciences system due to Severe Acute Respiratory Syndrome (SARS-CoV-2) virus. The majority of health professional students received their education via face-to-face prior to the pandemic. The pandemic altered their traditional pedagogical method of face-to-face to online instruction. The health professional school faculty offer the best instruction in a lecture hall not on a computer screen using Zoom. This study was designed to analyze how the faculty adapted in moving to an online instructional method, …

Leveraging Multiple Data Sources: How Catch Data, Metadata, And Genetic Samples Can Aid The Recovery Of Endangered Smalltooth Sawfish (Pristis Pectinata), Kelcee Smith

LSU Doctoral Dissertations

The small population sizes characteristic of many imperiled species means that they are vulnerable to both demographic and genetic extinction threats. Responses to these threats (e.g., population trends, genetic diversity estimates) are often difficult to obtain, but critical for conservation. Thus, researchers studying imperiled species may have to consult multiple data sources, collaborate with a wide variety of stakeholders, or ask new questions about previously collected data. I used this approach to understand more about the United States (U.S.) population of Pristis pectinata, an endangered elasmobranch that has declined up to 95% due to habitat loss and bycatch in …

Characterization Of Resistance To Two Crambid Stem Borers Among Louisiana Sugarcane Cultivars, Leonardo D. Salgado

LSU Master's Theses

Cultivar resistance is a key management strategy for the stem borer complex (Lepidoptera: Crambidae) in Louisiana sugarcane, but mechanisms of resistance are not well understood. This research evaluated the potential mechanisms of cultivar resistance to Diatraea saccharalis and Eoreuma loftini among commercial sugarcane cultivars and experimental clones through a series of field screenings, greenhouse trials, and diet incorporation assays. The stem borer resistant standard HoCP 85-845 and cultivar L 01-299 were among the cultivars with the lowest borer injury levels in both field and greenhouse trials. Cultivars HoCP 00-950, L 12-201, and HoCP 14-885 were among the most heavily injured …

A Geospatial And Statistical Analysis Of Dropout In Louisiana Public High Schools, Michael D. Stein

LSU Master's Theses

Students dropping out of high school is a nationwide problem, plaguing communities and often greatly reducing the prospects of a quality life for those students who do not complete their high school educations. Louisiana consistently has among the highest public high school dropout rates in the United States, and often the highest. This geospatial and statistical study aims to identify the factors that correlate with high school dropout in Louisiana public high schools, specifically, and to produce detailed maps of the dropout rates across the state to identify the schools most afflicted.

Extensive school-level data from five academic years (2014-15 …

The Relationship Between Emotion Regulation And Substance Use Treatment Attrition, Melanie Ruth Roys

LSU Doctoral Dissertations

Severe substance use disorders are characterized by chronic cycles of relapse; however, individuals who complete substance use treatment are less likely to experience relapse. Research has focused on trying to identify factors that predict treatment dropout to help improve treatment outcomes. Most of this research has focused on examining demographic and patient-specific factors, with little success in reliably predicting treatment attrition. There has been less focus on investigating transdiagnostic factors that span across discrete psychological diagnoses and demographics. The present study sought to determine if self-report and behavioral measures related to emotion regulation predicted inpatient substance use treatment dropout above …

Isolation Of Foliar Fungi From Roseau Cane (Phragmites Australis) In Coastal Louisiana, David M. Galo Espinal

LSU Master's Theses

Roseau cane (Phragmites australis) is a wild plant with an extensive root system that is useful in areas vulnerable to soil erosion. In Louisiana, this plant plays an important role protecting the coastal infrastructure of the lower Mississippi River delta (MRD). Currently, P. australis growing in the MRD is being affected by a die-off, which has been associated with several biotic and abiotic factors.

Plant pathogenic fungi is a biotic factor that negatively affect plant growth. Therefore, foliar fungi were isolated from plants growing in one die-off affected area (MRD) and two non-affected areas (Pecan Island and Manchac) …

Effect Of Forage Management Strategies And Land Use Change On Nitrogen Budget And Soil Health Parameters In Pasture Systems, Yili Meng

LSU Doctoral Dissertations

Pastures produce hay for livestock, and they conserve soil, water, and air resources. However, high nitrogen (N) fertilizer demands in pasture production have significant implication on greenhouse gas emission and environmental pollution. Appropriate forage management strategies can reduce environmental N loss and improve soil health, to enhance the long-term pasture productivity. Therefore, this study was carried out to investigate the effects of management strategies on N budgets and soil health parameters in subtropical pastures. Both field and laboratory experiments were conducted to evaluate the effects of N stabilizers including urease inhibitor and nitrification inhibitor on pasture yield, greenhouse gas emission, …

Effects Of Beach Nourishment Project On Coastal Geomorphology And Mangrove Dynamics In Southern Louisiana, Usa, Marcelo Cancela Lisboa Cohen, Adriana Vivan De Souza, Kam-Biu Liu, Erika Rodrigues, Qiang Yao, Luiz Carlos Ruiz Pessenda, Dilce Rossetti, Junghyung Ryu, Marianne Dietz

Faculty Publications

No abstract provided.

Fisheries Food Webs: Quantifying Habitat-Use, Trophic Structure, And Energetic Pathways In Coastal Tanzania, Mario Fernando Hernandez

LSU Doctoral Dissertations

Commercial and recreational fisheries are a valuable resource to millions of people around the world. Developing countries are particularly dependent on the revenue provided by locally harvested fish with total exports from these nations valued at $80 billion USD. For Tanzania, fisheries provide not only a source of revenue but an important source of protein with an estimated 25 to 30kg of fish consumed per person every year. There is no doubt that high fisheries production is critical to the well-being of millions of livelihoods along the Tanzanian coast. An important but poorly understood driver of fisheries production is the …

Environmental Perception In Colombia's Páramo Protected Areas, Juliana Delgado

LSU Master's Theses

This thesis analyzes the gap between farmers' environmental perceptions in Téquita, a small village in Colombia, and the definition of protected areas has led to a conflict for the use of natural resources. I examine if the protected area's policies have dealt with the social and ecological issues in the páramos and recognized the social construction of the landscape, farmers' identities, and their interpretations about work and land. The case study focuses on Güina High Mountain in the Guantiva-La Rusia páramo complex, which recently the Colombian government declared as a protected area. In light of anthropologist Tim Ingold's meaning of …

Effects Of Salinity On Eastern Oysters: Locating Lower-Salinity Tolerant Populations And Defining Resource Zones Suitable To Restoration, Fisheries, And Aquaculture., Lauren Swam

LSU Master's Theses

Eastern oysters (Crassostrea virginica) provide valuable ecosystem services and support a productive commercial industry in the northern Gulf of Mexico. Declining abundance from water quality changes and other factors drives development of management and restoration strategies focused on a comprehensive, metapopulation approach. Identifying oyster resource zones based on water quality combined with selective breeding of oysters adapted to specific conditions provides strategies to support aquaculture development and ensure resilient oyster populations and high production. Using 2015-2019 satellite-derived continuous salinity and temperature data for coastal Louisiana, this work created maps defining oyster resource zones supportive of (1) broodstock sanctuary …

Numerical And Field Study Of Tidal And Subtidal Dynamics In A Bar-Built Estuary: Barataria Bay, Gulf Of Mexico, Ali Reza Payandeh

LSU Doctoral Dissertations

This study investigated tidal and subtidal dynamics of water level, currents, and suspended sediment concentration (SSC) in Barataria Bay, a shallow bar-built estuary of the Northern Gulf of Mexico. First, the local and remote wind forcing contribution on subtidal water level and current variability were examined using three different methods: (i) statistical analysis of observed data, (ii) an analytical model and (iii) a 2-D barotropic numerical model. Results suggested that the remote and local wind effects were equally important at the bay mouth, however local winds were the dominant forcing driver inside the bay. The amplitudes of subtidal fluctuations induced …

Habitat Use And Morphology Of Birds In "Intact" Amazonia Under Changing Climate, Vitek Jirinec

LSU Doctoral Dissertations

Neotropical forests contain the core of global avian diversity. Of these, the Amazon rainforest is the largest, but ~20% has already been lost to deforestation, inspiring research into the effects of clearing and fragmentation on forest birds. These studies have consistently shown that insectivorous birds that forage on or near the ground are the most sensitive species to forest disturbance. As a preamble to our study, we synthesized bird capture data collected over 40 years within continuous forest far from human disturbance. Remarkably, we found that terrestrial and near-ground insectivores have shown substantial abundance declines even within primary forest. The …

Electrochemical Reduction Of Hexavalent Chromium In Acetonitrile Using Glassy Carbon Electrodes, Temitope Jegede

LSU Master's Theses

Hexavalent chromium Cr(VI), a form of chromium mainly generated through industrial processes, has attracted great research interests due to its severe toxicity to biological systems. A common way to remove hexavalent chromium from industrial wastes is through reduction to the non-toxic trivalent state. To this end, methods such as chemical reduction, chemical precipitation and coagulation have been used. However, these methods are limited by poor removal efficiency, formation of secondary pollutants (sludge), and are mostly applicable to aqueous solutions. Recently, electrochemical methods have been investigated for reducing hexavalent chromium, but there is a lack of data on the reduction of …

Do Neighbours Matter? The Effect Of Single‐ And Mixed‐Species Sowing Density On Seed Germination Of Annual Wetland Plants, Francielli Bao, Davi Rodrigo Rossatto, Arnildo Pott, Tracy Elsey‐Quirk, Marco Antonio Assis, Rafael Arruda, Desirée Marques Ramos, Borja Jiménez‐Alfaro

Faculty Publications

No abstract provided.

A Systematic Review Of Dietary Supplements And Alternative Therapies For Weight Loss, John A. Batsis, John W. Apolzan, Pamela J. Bagley, Heather B. Blunt, Vidita Divan, Sonia Gill, Angela Golden, Shalini Gundumraj, Steven B. Heymsfield, Scott Kahan, Katherine Kopatsis, Ava Port, Elizabeth Prout Parks, Clifford A. Reilly, Domenica Rubino, Katherine H. Saunders, Ryan Shean, Luai Tabaza, Abishek Stanley, Beverly G. Tchang, Shivani Gundumraj, Srividya Kidambi

Clinical Research Faculty Publications

Objective: Dietary supplements and alternative therapies are commercialized as a panacea for obesity/weight gain as a result of the minimal regulatory requirements in demonstrating efficacy. These products may indirectly undermine the value of guideline-driven obesity treatments. Included in this study is a systematic review of the literature of purported dietary supplements and alternative therapies for weight loss. Methods: A systematic review was conducted to evaluate the efficacy of dietary supplements and alternative therapies for weight loss in participants aged ≥18 years. Searches of Medline (PubMed), Cochrane Library, Web of Science, CINAHL, and Embase (Ovid) were conducted. Risk of bias and …

Louisiana Agriculture Summer, 2021, Lsu Agcenter

Louisiana Agriculture

No abstract provided.

Phylogenomic Analyses Reveal Non-Monophyly Of The Antbird Genera Herpsilochmus And Sakesphorus (Thamnophilidae), With Description Of A New Genus For Herpsilochmus Sellowi, G A. Bravo, B M. Whitney, R Belmonte-Lopes, M R. Bornschein, G A. Bravo, R Beco, J Battilana, L N. Naka, A Aleixo, M R. Pie, L F. Silveira, E P. Derryberry, R T. Brumfield

Faculty Publications

The family Thamnophilidae is a species-rich Neotropical radiation of passerine birds. Current classification of its 235 species is mostly based on morphological similarities, but recent studies integrating comprehensive phenotypic and phylogenetic data have redefined taxonomic limits of several taxa. Here, we assess generic relationships of Herpsilochmus, Sakesphorus, Thamnophilus, Biatas, and Dysithamnus using DNA sequences from the mitochondrion, nuclear exons, and ultraconserved elements, with further attention to interspecific relationships within Herpsilochmus. We show that Herpsilochmus and Sakesphorus are not monophyletic. We resolve Herpsilochmus sellowi as a deep-branch sister to the monotypic genus Biatas and Sakesphorus cristatus as sister to a clade …