Digital Commons Network^™

Responses Of Phytoplankton Communities To The Effect Of Both River Plume And Coastal Upwelling, Zhuyin Tong, Lingqi Ma, Shujie Cai, Lei Wang, Wupeng Xiao, Bangqin Huang, Edward A. Laws

Faculty Publications

River plumes and coastal upwelling systems are both nutrient-abundant habitats compared to the open ocean, and the mechanisms that structure the phytoplankton community when these occur together are unclear. In this study we investigated the dynamics and drivers of phytoplankton biomass and community composition in the Pearl River plume-coastal upwelling system on the northern South China Sea shelf during summer. We found that phytoplankton biomass was lower in the plume than in upwelled water. Diatoms were the only dominant group in the upwelled water. In contrast, diatoms and Synechococcus were co-dominant in the plume, and the negative correlation between the …

Oxidation 1-Methyl Naphthalene Based On The Synergy Of Environmentally Persistent Free Radicals (Epfrs) And Pahs In Particulate Matter (Pm) Surface, Ajit Ghimire, Farhana Hasan, Xia Guan, Phillip Potter, Chuqi Guo, Slawo Lomnicki

Faculty Publications

Studies of the environmental fate through the interactions of particle-associated polycyclic aromatic hydrocarbons (PAHs) with environmentally persistent free radicals (EPFRs) are presented. The formation of PAHs and EPFRs typically occurs side by side during combustion-processes. The laboratory simulation studies of the model PAH molecule 1-Methylnaphthalene (1-MN) interaction with model EPFRs indicate a transformational synergy between these two pollutants due to mutual and matrix interactions. EPFRs, thorough its redox cycle result in the oxidation of PAHs into oxy-/hydroxy-PAHs. EPFRs have been shown before to produce OH radical during its redox cycle in aqueous media and this study has shown that produced …

Excluded Minors Are Almost Fragile Ii: Essential Elements, Nick Brettell, James Oxley, Charles Semple, Geoff Whittle

Faculty Publications

Let M be an excluded minor for the class of P-representable matroids for some partial field P, let N be a 3-connected strong P-stabilizer that is non-binary, and suppose M has a pair of elements {a,b} such that M﹨a,b is 3-connected with an N-minor. Suppose also that |E(M)|≥|E(N)|+11 and M﹨a,b is not N-fragile. In the prequel to this paper, we proved that M﹨a,b is at most five elements away from an N-fragile minor. An element e in a matroid M^′ is N-essential if neither M^′/e nor M^′﹨e has an N-minor. In this paper, we prove …

The Excluded Minors For 2- And 3-Regular Matroids, Nick Brettell, James Oxley, Charles Semple, Geoff Whittle

Faculty Publications

The class of 2-regular matroids is a natural generalisation of regular and near-regular matroids. We prove an excluded-minor characterisation for the class of 2-regular matroids. The class of 3-regular matroids coincides with the class of matroids representable over the Hydra-5 partial field, and the 3-connected matroids in the class with a U2,5- or U3,5-minor are precisely those with six inequivalent representations over GF(5). We also prove that an excluded minor for this class has at most 15 elements.

Ab Initio Single-Neutron Spectroscopic Overlaps In Lithium Isotopes, G. H. Sargsyan, K. D. Launey, R. M. Shaffer, S. T. Marley, N. Dudeck, A. Mercenne, T. Dytrych, J. P. Draayer

Faculty Publications

We calculate single-neutron spectroscopic overlaps for lithium isotopes in the framework of the ab initio symmetry-adapted no-core shell model. We report the associated neutron-nucleus asymptotic normalization coefficients (ANCs) and spectroscopic factors (SFs) that are important ingredients in many reaction cross-section calculations. While spectroscopic factors have been traditionally extracted from experimental cross sections, their sensitivity on the type of reactions, the energy, and the underlying models point to the need for determining SFs from first-principle structure considerations. As illustrative examples, we present Li6+n, Li7+n, and Li8+n, and we show that the results are in a good agreement with those of other …

Discovery Of X-Ray Polarization From The Black Hole Transient Swift J1727.8−1613, Alexandra Veledina, Fabio Muleri, Michal Dovčiak, Juri Poutanen, Ajay Ratheesh, Fiamma Capitanio, Giorgio Matt, Paolo Soffitta, Allyn F. Tennant, Michela Negro, Philip Kaaret, Enrico Costa, Adam Ingram, Jiří Svoboda, Henric Krawczynski, Stefano Bianchi, James F. Steiner, Javier A. García, Vadim Kravtsov, Anagha P. Nitindala, Melissa Ewing, Guglielmo Mastroserio, Andrea Marinucci, Francesco Ursini, Francesco Tombesi, Sergey S. Tsygankov, Yi Jung Yang, Martin C. Weisskopf, Sergei A. Trushkin, Elise Egron, Maria Noemi Iacolina, Maura Pilia, Lorenzo Marra

Faculty Publications

We report the first detection of the X-ray polarization of the bright transient Swift J1727.8−1613 with the Imaging X-ray Polarimetry Explorer. The observation was performed at the beginning of the 2023 discovery outburst, when the source resided in the bright hard state. We find a time- and energy-averaged polarization degree of 4.1% ± 0.2% and a polarization angle of 2.°2 ± 1.°3 (errors at 68% confidence level; this translates to ∼20σ significance of the polarization detection). This finding suggests that the hot corona emitting the bulk of the detected X-rays is elongated, rather than spherical. The X-ray polarization angle is …

Transiting Exoplanet Yields For The Roman Galactic Bulge Time Domain Survey Predicted From Pixel-Level Simulations, Robert F. Wilson, Thomas Barclay, Brian P. Powell, Joshua Schlieder, Christina Hedges, Benjamin T. Montet, Elisa Quintana, Iain Mcdonald, Matthew T. Penny, Néstor Espinoza, Eamonn Kerins

Faculty Publications

The Nancy Grace Roman Space Telescope (Roman) is NASA’s next astrophysics flagship mission, expected to launch in late 2026. As one of Roman’s core community science surveys, the Galactic Bulge Time Domain Survey (GBTDS) will collect photometric and astrometric data for over 100 million stars in the Galactic bulge in order to search for microlensing planets. To assess the potential with which Roman can detect exoplanets via transit, we developed and conducted pixel-level simulations of transiting planets in the GBTDS. From these simulations, we predict that Roman will find between ∼60,000 and ∼200,000 transiting planets—over an order of magnitude more …

Widespread Sympatry In A Species-Rich Clade Of Marine Fishes (Carangoidei), Jessica R. Glass, Richard C. Harrington, Peter F. Cowman, Brant C. Faircloth, Thomas J. Near

Faculty Publications

A universal paradigm describing patterns of speciation across the tree of life has been debated for decades. In marine organisms, inferring patterns of speciation using contemporary and historical patterns of biogeography is challenging due to the deficiency of species-level phylogenies and information on species' distributions, as well as conflicting relationships between species' dispersal, range size and co-occurrence. Most research on global patterns of marine fish speciation and biogeography has focused on coral reef or pelagic species. Carangoidei is an ecologically important clade of marine fishes that use coral reef and pelagic environments. We used sequence capture of 1314 ultraconserved elements …

Exposing The Error Hidden In Plain Sight: A Critique Of Calder's (1983) Group Selectionist Seed-Dispersal Hypothesis For Mistletoe “Mimicry” Of Host Plants, Kyle E. Harms, David M. Watson, Luis Y. Santiago-Rosario, Sarah Mathews

Faculty Publications

Some mistletoe species (Loranthaceae) resemble their host plants to a striking degree. Various mechanisms have been proposed for the developmental origins of novel traits that cause mistletoes to appear similar to their hosts, as well as for the adaptive phenotypic evolution of such traits. Calder (1983) proposed a logically flawed group selectionist seed-dispersal hypothesis for mistletoes to resemble their hosts. Calder's (1983) hypothesis does not provide a viable potential explanation for mistletoe resemblance to hosts.

A Target Enrichment Probe Set For Resolving Phylogenetic Relationships In The Coffee Family, Rubiaceae, Laymon D. Ball, Ana M. Bedoya, Charlotte M. Taylor, Laura P. Lagomarsino

Faculty Publications

Premise: Rubiaceae is among the most species-rich plant families, as well as one of the most morphologically and geographically diverse. Currently available phylogenies have mostly relied on few genomic and plastid loci, as opposed to large-scale genomic data. Target enrichment provides the ability to generate sequence data for hundreds to thousands of phylogenetically informative, single-copy loci, which often leads to improved phylogenetic resolution at both shallow and deep taxonomic scales; however, a publicly accessible Rubiaceae-specific probe set that allows for comparable phylogenetic inference across clades is lacking. Methods: Here, we use publicly accessible genomic resources to identify putatively single-copy nuclear …

Environment And Host Genetics Influence The Biogeography Of Plant Microbiome Structure, Na Wei, Jiaqi Tan

Faculty Publications

To understand how microbiota influence plant populations in nature, it is important to examine the biogeographic distribution of plant-associated microbiomes and the underlying mechanisms. However, we currently lack a fundamental understanding of the biogeography of plant microbiomes across populations and the environmental and host genetic factors that shape their distribution. Leveraging the broad distribution and extensive genetic variation in duckweeds (the Lemna species complex), we identified key factors that governed plant microbiome diversity and compositional variation geographically. In line with the microbial biogeography of free-living microbiomes, we observed higher bacterial richness in temperate regions relative to lower latitudes in duckweed …

Erratum: Correction To: Environment And Host Genetics Influence The Biogeography Of Plant Microbiome Structure (Microbial Ecology (2023) 86 4 (2858-2868)), Na Wei, Jiaqi Tan

Faculty Publications

No abstract provided.

Influences Of Yogurt With Functional Ingredients From Various Sources That Help Treat Leaky Gut On Intestinal Barrier Dysfunction In Caco-2 Cells, Ricardo S. Aleman, Ryan Page, Roberto Cedillos, Ismael Montero-Fernández, Jhunior Abraham Marcia Fuentes, Douglas W. Olson, Kayanush Aryana

Faculty Publications

The impact of yogurts made with starter culture bacteria (L. bulgaricus and S. thermophilus) and supplemented with ingredients (maitake mushrooms, quercetin, L-glutamine, slippery elm bark, licorice root, N-acetyl-D-glucosamine, zinc orotate, and marshmallow root) that can help treat leaky gut were investigated using the Caco-2 cell monolayer as a measure of intestinal barrier dysfunction. Milk from the same source was equally dispersed into nine pails, and the eight ingredients were randomly allocated to the eight pails. The control had no ingredients. The Caco-2 cells were treated with isoflavone genistein (negative control) and growth media (positive control). Inflammation was stimulated using an …

Synergistic In Vitro Antiviral Effect Of Combinations Of Ivermectin, Essential Oils, And 18-(Phthalimid-2-Yl)Ferruginol Against Arboviruses And Herpesvirus, Liliana Betancur-Galvis, Orlando José Jimenez-Jarava, Fatima Rivas, William E. Mendoza-Hernández, Miguel A. González-Cardenete

Faculty Publications

Combining antiviral drugs with different mechanisms of action can help prevent the development of resistance by attacking the infectious agent through multiple pathways. Additionally, by using faster and more economical screening methods, effective synergistic drug candidates can be rapidly identified, facilitating faster paths to clinical testing. In this work, a rapid method was standardized to identify possible synergisms from drug combinations. We analyzed the possible reduction in the antiviral effective concentration of drugs already approved by the FDA, such as ivermectin (IVM), ribavirin (RIBA), and acyclovir (ACV) against Zika virus (ZIKV), Chikungunya virus (CHIKV), and herpes virus type 2 (HHV-2). …

Effect Of Sampling Method On Detection Of The Equine Uterine Microbiome During Estrus, B. A. Heil, M. Van Heule, S. K. Thompson, T. A. Kearns, E. L. Oberhaus, G. King, P. Daels, P. Dini, J. L. Sones

Faculty Publications

Bacterial endometritis is among the most common causes of subfertility in mares. It has a major economic impact on the equine breeding industry. The sensitivity of detecting uterine microbes using culture-based methods, irrespective of the sample collection method, double-guarded endometrial swab, endometrial biopsy, or uterine low-volume lavage (LVL), is low. Therefore, equine bacterial endometritis often goes undiagnosed. Sixteen individual mares were enrolled, and an endometrial sample was obtained using each method from all mares. After trimming, quality control and decontamination, 3824 amplicon sequence variants were detected in the dataset. We found using 16S rRNA sequencing that the equine uterus harbors …

Editorial Introduction: Exploring Policy Theories, Narratives, And Policing, Geoboo Song, Melissa K. Merry, Holly L. Peterson, Davor Mondom, Briana Huett, Izehi Oriaghan, Creed Tumlison, Camille Gilmore, Gwen Arnold, Aaron Smith-Walter, Saba Siddiki, Heasun Choi

Faculty Publications

No abstract provided.

Understanding And Modeling Drivers’ En-Route Diversion Behavior During Congestion, Mohammad Shapouri

LSU Doctoral Dissertations

In the field of transportation, traffic assignment models primarily have been used to forecast driver route preferences, translating their choices into traffic flow patterns across networks. These models are grounded in distinct behavioral theories and strive to explain how drivers navigate routes based on network features and personal tendencies. Using an aggregation approach, conventional traffic assignment models distribute demand among paths, considering utility and attractiveness. Despite their prevalent use in transportation planning and operations, the fundamental behavioral assumptions of these models have rarely been thoroughly explored. This gap is further compounded by their limited consideration of real-time adjustments and choices …

Electrophertic Deposition And Characterization Of Molybdenum Disulfide On Silicon Substrates, Alex J. Young

LSU Doctoral Dissertations

The electrical characteristics of 2D materials such as high electron mobility and current density are of great interest to various fields from optoelectronics to renewable energy. Researchers have focused their efforts on transition metal dichalcogenides (TMDCs) due to their direct energy band gap. One such TMDC that has garnered much attention is molybdenum disulfide (MoS2). MoS2 has electrical properties comparable to graphene and is a TMDC with characteristics amenable to applications such as solar cells and sensors. Commonly deposited through time-consuming and complex deposition methods such as chemical vapor deposition (CVD), the viability of MoS2 as an electronic material will …

Comparison Of Rheological Methods To Measure Grease Degradation, Alan Gurt, Michael Khonsari

Faculty Publications

In a previous paper, methods that have been used to quantify grease mechanical degradation were compared, finding that crossover stress is a practical method for estimating the cone penetration value of a grease using a small sample. This paper covers techniques that have not generally been applied to modeling grease degradation and indicates their usefulness in characterizing the state of a grease. Three methods are examined, each using a different flow profile: rotation, oscillation, and normal force/extension. It is found that crossover stress is likely still the best choice for estimating cone penetration, and a fast, practical method is introduced …

An Investigation Into The Challenges Of Contemporary Additive Manufacturing: Insights Into The Metallurgical Response Of Materials And Relevant Solution, Huan Ding

LSU Doctoral Dissertations

Additive Manufacturing (AM) has gained attention in recent years due to its unique capabilities in the fabrication of complex parts. As with any new research, there is still a lack of sufficient understanding in the field of additive manufacturing, and further investigation is needed to solve existing problems. Ultimately, the aim is to enable the widespread use of AM components across various industries.

Chapter One provides a brief introduction to the background and current bottlenecks of additive manufacturing technology. Chapter two focuses on the development of high-strength 7075 aluminum alloy (Al7075) for Fused Deposition Modeling and Sintering (FDMS) technology. Al7075 …

The Effects Of Ethanol Preservation On High-Molecular Weight Dna, Maia Jackson

Honors Capstones

No abstract provided.

Politics In Applicant Attraction And Recruitment: Firm Response To Abortion Legislation And Its Impact On Applicant Interest, Madeleine Coward

Honors Capstones

No abstract provided.

Effectiveness Of Static Versus Dynamic Language Assessments, Lauren Betzer

Honors Capstones

No abstract provided.

Lipid Oxidative Damage In Mitochondria From Artemia Franciscana Embryos: Anoxic Challenge Followed By Normoxic Recoveries Of Increasing Duration, Samantha Shirmer

Honors Capstones

No abstract provided.

Estimating Household Willingness To Pay For Improved Water Quality Via Community Sewage System, Daniel Harris

Honors Capstones

No abstract provided.

The Intracellular Localization And Function Of The Stress Response Kinase C-Jun Amino- Terminal Kinase In Drosophila Melanogaster, Claire Brescher

Honors Capstones

No abstract provided.

Reactive Oxygen Species Production By Isolated Mitochondria From Embryos Of Artemia Franciscana During Normoxic Recovery After Anoxia, Olivia G. Moncrief

Honors Capstones

No abstract provided.

Controlling Guest Binding To Transition Metal Hosts Via Redox Stimuli, Jasmine S. Sanford

LSU Doctoral Dissertations

Several metal complexes were investigated as potential hosts to execute controllable host- guest interactions using a redox stimulus. Previously, our group has synthesized new Cu^II m-xylylenebis(pyridyltriazole) (m-xpt) hosts and their redox properties were analyzed. In Chapter 2, we take advantage of the Cu^II host’s ability to perform redox to investigate its interaction with chloride guest ions. This study was executed with two main Cu-xpt hosts: [Cu₂(m- xpt)₂(NO₃)₂](PF₆)₂ and [Cu₂(m-xpt)₂Cl₂]Cl₂. The host-guest interaction was analyzed with additions …

Conducting Enchantment: Organized Sound And Ritual Spaces In Modern And Ancient Worlds, Haley Stuckey

Honors Capstones

No abstract provided.

A Descriptive Study Of Louisiana 4-H 8th Through 12th Graders' Perceptions Of Career And College Readiness, Carrie M. Lane

LSU Master's Theses

As youth leave primary education and enter college or a career path, preparing those youth to ensure success has fallen, in large part, upon formal and non-formal youth educators. Encouraging students to apply and complete college has been a focus of education professionals for many years. Historically, gauging college and career readiness (CCR), academic institutions have relied on academic performance in areas of English Language Arts and Mathematics (Mattern, et. al, 2014). The use of academic focused measures instead of student-based evaluation had its drawbacks. While core education is important, measuring soft skills needed for the workforce and college environment …