Digital Commons Network^™

Evaluation Of Soybean Response To Sulfur Fertilizer Rates And Sources, Md Enamul Haque Moni

LSU Master's Theses

Sulfur (S) deficiency has become a significant concern for producers due to over 90% reduction in atmospheric-S deposition since the “Clean Air Act” was established. Soil organic matter, another key source of S, is steadily declining due to continuous tillage. So, we evaluated soybean [Glycine max (L.) Merr.] yield and leaf-S concentration responses to six fertilizer-S rates (0, 11, 22, 34, 45, and 67 kg S ha⁻¹) across 50 site-years, and six fertilizer-S sources (no-S check, Ammonium Sulfate (AMS), Sul4r-Plus/Gypsum, K-Mag, Tiger90CR, and Poly4) across 9 site-years in Louisiana from 2023-2024. In S rate study, soybean yield responded positively to …

A Numerical Assessment Of Ocean Alkalinity Enhancement Efficiency On A River-Dominated Continental Shelf—A Case Study In The Northern Gulf Of Mexico, Yanda Ou, Z. George Xue, Xinping Hu

Faculty Publications

A robust high-resolution coupled hydrodynamic-biogeochemical model was applied to the northern Gulf of Mexico to assess the efficiency of river- and ocean-sourced ocean alkalinity enhancement (OAE). Sensitivity tests indicate that the effectiveness of OAE-induced CO2 uptake is primarily influenced by the amount of alkalinity introduced and local wind-driven mixing, with the former determining the overall uptake and the latter affecting short-term variability. Compared to ocean-sourced OAE (direct ocean release), river-sourced OAE (elevated river alkalinity) is more effective and sustainable. River-sourced OAE has higher CO2 uptake efficiency with reduced spatial and temporal uncertainty and greater overall CO2 uptake. For river-sourced OAE, …

An Integrated Global-To-Regional Scale Workflow For Simulating Climate Change Impacts On Marine Ecosystems, Kelly Ortega-Cisneros, Denisse Fierros-Arcos, Max Lindmark, Camilla Novaglio, Phoebe Woodworth-Jefcoats, Tyler D. Eddy, Marta Coll, Elizabeth Fulton, Ricardo Oliveros-Ramos, Jonathan Reum, Yunne Jai Shin, Cathy Bulman, Leonardo Capitani, Samik Datta, Kieran Murphy, Alice Rogers, Lynne Shannon, George A. Whitehouse, Ezekiel Adekoya, Beatriz S. Dias, Alba Fuster-Alonso, Cecilie Hansen, Bérengère Husson, Vidette Mcgregor, Alaia Morell, Hem Nalini Morzaria Luna, Jazel Ouled-Cheikh, James Ruzicka, Jeroen Steenbeek, Ilaria Stollberg, Roshni C. Subramaniam, Vivitskaia Tulloch, Andrea Bryndum-Buchholz

Faculty Publications

As the urgency to evaluate the impacts of climate change on marine ecosystems increases, there is a need to develop robust projections and improve the uptake of ecosystem model outputs in policy and planning. Standardizing input and output data is a crucial step in evaluating and communicating results, but can be challenging when using models with diverse structures, assumptions, and outputs that address region-specific issues. We developed an implementation framework and workflow to standardize the climate and fishing forcings used by regional models contributing to the Fisheries and Marine Ecosystem Model Intercomparison Project (FishMIP) and to facilitate comparative analyses across …

Empowering Citizens Through The Development And Deployment Of A Community-Based Environmental Health Reporting Tool, Willow Sauermilch, Jennifer Irving, Margaret Reams, Chuqi Guo, Stephania Cormier, Jennifer Richmond-Bryant

Division of Basic Science Faculty Publications

Community-based participatory research provides communities with an avenue to actively collaborate with environmental researchers. The research aims to gain insight into critical problems of concern to community members while maintaining community autonomy over the research and its outcomes. This article describes the development and implementation of an environmental health communication tool designed to meet the needs of residents of Colfax, Louisiana, a rural community with limited technological access, which is engaging in advocacy with federal and state regulatory agencies to prohibit open burning and open detonation of military and Superfund wastes at a nearby thermal treatment site. We discuss how …

A Data-Driven Approach To Enhance The Prediction Of Bacteria–Metabolite Interactions In The Human Gut Microbiome Using Enzyme Encodings And Metabolite Structural Embeddings, Gopal Srivastava, Michal Brylinski

Faculty Publications

Background: The human gut microbiome is critical for host health by facilitating essential metabolic processes. Our study presents a data-driven analysis across 312 bacterial species and 154 unique metabolites to enhance the understanding of underlying metabolic processes in gut bacteria. The focus of the study was to create a strategy to generate a theoretical (negative) set for binary classification models to predict the consumption and production of metabolites in the human gut microbiome. Results: Our models achieved median balanced accuracies of 0.74 for consumption predictions and 0.95 for production predictions, highlighting the effectiveness of this approach in generating reliable negative …

Interactive Effects Of Co2, Temperature, And Nitrate Limitation On The Growth And Physiology Of Strain Ccmp 1334 Of The Marine Cyanobacterium Synechococcus (Cyanophyceae), Alyssa K. Sharbaugh, Edward A. Laws

Faculty Publications

The marine cyanobacterium Synecococcus sp. (CCMP 1334) was grown in a continuous culture system on a 12:12 h light:dark cycle at all combinations of low and high pCO2 (400 and 1000 ppmv, respectively), nutrient availability (nitrate-limited and nutrient-replete conditions), and temperatures of 21, 24, 28, 32, and 35°C. The maximum nutrient-replete growth rate was ~1.15 day⁻¹ at 32–35°C. Median nutrient-replete growth rates were higher at 1000 ppmv than at 400 ppmv pCO2 at all temperatures. Carbon:nitrogen ratios were independent of pCO2 at a fixed relative growth rate (i.e., growth rate ÷ nutrient-replete growth rate) but decreased with increasing temperature. …

Extragalactic Magnetar Giant Flare Grb 231115a: Insights From Fermi /Gbm Observations, Aaron C. Trigg, Rachael Stewart, Alex Van Kooten, Eric Burns, Matthew G. Baring, Dmitry D. Frederiks, Daniela Huppenkothen, Brendan O-Connor, Oliver J. Roberts, Zorawar Wadiasingh, George Younes, Narayana Bhat, Michael S. Briggs, Malte Busmann, Adam Goldstein, Daniel Gruen, Lei Hu, Chryssa Kouveliotou, Michela Negro, Antonella Palmese, Arno Riffeser, Lorenzo Scotton, Dmitry S. Svinkin, Peter Veres, Raphael Zöller

Faculty Publications

Magnetar giant flares (MGFs) are the extremely short, energetic transients originating from highly magnetized neutron stars. When observed in nearby galaxies, these rare events are nearly indistinguishable from cosmological short gamma-ray bursts. We present the analysis of GRB 231115A, a candidate extragalactic MGF observed by Fermi/GBM and localized by INTEGRAL to the starburst galaxy M82. This burst exhibits distinctive temporal and spectral characteristics, including a short duration and a high peak energy, consistent with known MGFs. Time-resolved analysis reveals rapid spectral evolution and a clear correlation between luminosity and spectral hardness, providing robust evidence of relativistic outflows. Archival Chandra data …

Beyond Water Surface Profiles: A New Iterative Methodology For 2d Model Calibration In Rivers Using Velocity Data From Multiple Cross-Sections, Fabian Rivera-Trejo, Gabriel Soto-Cortes, Kory M. Konsoer, Eddy J. Langendoen, Gaston Priego-Hernandez

Faculty Publications

Observed longitudinal water-surface profiles are commonly used to calibrate river hydrodynamic models, relying on assumptions of lateral uniformity in water surface elevation and velocity distribution. While suitable for 1D models, this approach has limitations in regard to 2D model calibration. When 2D flow measurements are available, a more robust quantitative evaluation is necessary to assess model accuracy. This study introduces a novel methodology to improve 2D model calibration and evaluate performance. High-resolution bathymetric and hydrodynamic data collected with a multibeam echosounder (MBES) and acoustic Doppler current profiler (ADCP) were aligned to compare observed and simulated flow velocities at matching spatial …

Ceres: Organic-Rich Sites Of Exogenic Origin?, R. Sarkar, A. Nathues, M. Hoffmann, E. Cloutis, K. Mengel, P. Singh, G. Thangjam, J. Hernandez, S. Karunatillake, M. Coutelier

Faculty Publications

Ceres, the largest object in the asteroid belt, is the only potential ocean world in the inner Solar System. Previous studies identified deposits of aliphatic organics in and around the Ernutet crater, and at small locations at Inamahari and Urvara craters. The origin of organics, either endogenic or exogenic, in these fresh exposures is still under debate. This study addresses the origin of the organics by analyzing their global distribution and geologic context. Our first step involved a global search for organic-rich sites that might have escaped previous detections. We achieved this by using a deep neural network, utilizing spectral …

Simulations Of Attosecond Metallization In Quartz And Diamond Probed With Inner-Shell Transient Absorption Spectroscopy, Lucas Kurkowski, Adonay Sissay, Mengqi Yang, Alexander Meyer, Kenneth Lopata

Faculty Publications

When dielectrics are hit with intense infrared (IR) laser pulses, transient metalization can occur. The initial attosecond dynamics behind this metallization are not entirely understood. Therefore, simulations are needed to understand this process and to help interpret experimental observations of it, such as with attosecond transient absorption (ATA). In this paper, we present first-principles simulations of ATA based on bulk-mimicking clusters and real-time time-dependent density functional theory (RT-TDDFT), with Koopmans-tuned range-separated hybrid functionals and Gaussian basis sets. Our method gives good agreement with the experiment for the breakdown threshold in silica and diamond. This breakdown voltage corresponds to a Keldysh …

Corn And Soybean Responses To Phosphorus And Potassium Application Timings And Methods And Fertilizer Sources, Abrar Bin Wahid

LSU Master's Theses

This research was driven by concerns over phosphorus (P) and potassium (K) losses from fall-applied fertilizers and the increasing marketing popularity of liquid-P and K fertilizers over traditional granular-dry forms. We evaluated corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] yield and tissue nutrient concentration responses to fertilizer-P and K application timings, methods, and sources across 9-13 site-years on silt-loam soils in Louisiana from 2020-2024. For timing and method study, five treatments were evaluated: a no fertilizer-P and/or K check, fall broadcast followed by rehipping the seedbed, spring broadcast without rehipping, spring broadcast with rehipping, and spring top-of-bed …

The Full Range Leadership Model (Frlm): Department Head Perceptions Of Leadership Style And Development, Stephanie Elaine Heroman

LSU Doctoral Dissertations

The purpose of this study is to discover the perceived leadership styles of department heads as categorized by the Full Range Leadership Model (FRLM), developed by Avolio and Bass (1991). The FRLM categorizes leadership style along a continuum, from laissez-faire leadership, to transactional leadership, and ultimately transformational leadership. Even though department heads occupy a pivotal leadership role, many do not have formal leadership training, and instead rise to power through disciplinary expertise. This study will collect data on the experiences contributing to the development of leadership style in department heads. Understanding the leadership styles and experiences of department heads will …

The Eastern Oyster Behavioral Response To Low Salinity And Hypoxia In Controlled And Natural Settings, Siyah Yongue

LSU Master's Theses

Oyster aquaculture is expanding in the northern Gulf of Mexico, but climate change may challenge the sustainability of this industry. Projected increases in the frequency and intensity of low salinity and low dissolved oxygen (DO) periods could impact the behavior, metabolism, growth, and survival of oysters. Characterizing how oyster behavior links to environmental stressors could help better identify thresholds in their tolerance and inform predictive tools for aquaculture professionals. In this research, the effect of separate and concomitant exposures to low salinity and DO on the behavioral response of oysters was examined in the lab. The impact of other environmental …

Spin Caloritronics As A Probe Of Nonunitary Superconductors, Taiki Matsushita, Takeshi Mizushima, Yusuke Masaki, Satoshi Fujimoto, Ilya Vekhter

Faculty Publications

Superconducting spintronics explores the interplay between superconductivity and magnetism, sparking substantial interest in nonunitary superconductors as a platform for magneto-superconducting phenomena. However, identifying nonunitary superconductors remains challenging. We demonstrate that spin current driven by thermal gradients sensitively probes the nature of the condensate in nonunitary superconductors. Spin polarization of the condensate in momentum space induces the superconducting spin Seebeck effect, where a spin current is generated along thermal gradients without a thermoelectric charge current. Notably, the nonvanishing superconducting spin Seebeck effect provides a smoking gun evidence of nonunitary superconductivity because it reflects the spin polarization of the condensate in momentum …

Studying The Low-Lying Structure Of 9b Via The 10b(3he,A)9b Reaction, Rachel M. Shaffer

LSU Doctoral Dissertations

The unstable nature of ⁹B makes it a challenging isotope to study. The first-excited state of ⁹B has been particularly difficult to characterize. Since the first experimental observation of this state in 1955, many experimental and theoretical nuclear structure studies have sought to classify it, but with large discrepancies in the energy and width values from these results, the properties of the state remain inconclusive.

An experiment using the ¹⁰B(³He,α)⁹B reaction was performed at the John D. Fox Superconducting Linear Accelerator Laboratory at Florida State University in an effort to populate and characterize …

Baryon Number Violation Search, Tyler D. Stokes

LSU Doctoral Dissertations

Understanding the fundamental forces and symmetries of nature has long been a central goal of particle physics. While the Standard Model (SM) provides a successful framework, it does not guarantee the conservation of baryon number B or lepton number L, thus motivating searches for their violation. Proton decay, a fundamental process violating B, has been at the forefront of experimental searches for decades.

The discovery of the weak neutral current in 1973 unified the electromagnetic and weak forces and inspired the creation of Grand Unified Theories (GUTs) that also unify the strong force. In 1974, the first-ever GUT, …

Using Phylogenetics And Floral Evolution Of Sicklebill Hummingbird-Pollinated Centropogon Subgenus Centropogon To Support Undergraduate Research, Janet Mansaray

LSU Doctoral Dissertations

The genus Centropogon subgenus Centropogon, offers an ideal system for studying macroevolutionary patterns due to its diverse floral morphologies and specialized pollinator interactions. This subgenus comprises 55 species, mostly found in mid-elevation Andean forests, where many species exhibit abruptly curved flowers, often associated with pollination by sicklebill hummingbirds. Using phylogenomic approaches, we conducted the first densely sampled analysis of this group, confirming the monophyly of two sections. Our study highlighted extensive gene tree discordance, likely driven by incomplete lineage sorting. Floral curvature and inflorescence structure evolved in a correlated fashion, leading to multiple independent losses of traits linked to …

State-Of-Charge Estimation Using Deep Learning For Electric Vehicles, Samer Yahya Ribhe Tahboub

LSU Master's Theses

This thesis investigates the application of deep learning models for State of Charge (SOC) estimation in Battery Management Systems (BMS) for electric vehicles (EVs), focusing on optimizing EV range, lifespan, and performance while addressing challenges like range anxiety. The study explores three deep learning architectures—Long Short-Term Memory (LSTM), Bidirectional LSTM (BiLSTM), and Gated Recurrent Unit (GRU)—each designed to capture complex temporal dependencies in battery data. The LSTM model is trained on EV battery data, including voltage, current, temperature, and SOC, providing a strong baseline for SOC estimation. The BiLSTM model enhances accuracy by processing data in both forward and backward …

Johann Georg Hamann And The Liberal Project, Jesse D. Ansley

LSU Doctoral Dissertations

This dissertation examines the political thought of Johann Georg Hamann, his relationship to liberalism, and the importance to modern concerns for consensus formation and intercultural dialogue. This contributes to the line of literature sparked by Isaiah Berlin debating the political legacy of Hamann and its relation to the development of modern politics. Berlin labels Hamann an anti-rationalist whose current developed into the ideology of the Nazi party. My work supports the countervailing arguments that Hamann’s work is importantly different from the Romantics he inspired and even more so from the Nazis. By examining two complete works and a number of …

The Importance Of Fauna-Mediated Sediment O2 Consumption In The Ngom Hypoxic Zone, Hannah Beck, Kanchan Maiti

Faculty Publications

The northern Gulf of Mexico (NGOM) coastal shelf adjacent to the Mississippi and Atchafalaya rivers system experiences strong seasonal hypoxia in the late summer and coupled physical-biological models suggest that hypoxia formation in the NGOM is sensitive to benthic biogeochemical processes. However, the processes driving sediment oxygen consumption and their relationship to bottom oxygen concentration remain enigmatic. This study for the first time concurrently measured in situ total oxygen uptake (TOU) and diffusive oxygen uptake (DOU) during two different hypoxia seasons. The relatively large DOU: TOU ratio of 0.33 ± 0.07 observed during this study suggests more significant benthic infauna …

The Impact Of Seasonal Hydrological Disturbances On The Presence And Formation Of Toxic Cyanobacteria Blooms In Coastal Louisiana, Courtney Nicole Hammond, Sibel Bargu, Caitlin R.R. Turner, Matthew Hiatt, John R. White

Faculty Publications

Estuaries in the Gulf, especially Lake Pontchartrain Estuary in southeastern Louisiana, USA, are experiencing significant changes due to climate change and coastal restoration efforts. Lake Pontchartrain Estuary receives nutrient-rich Mississippi River water through a controlled diversion called Bonnet Carré Spillway (BCS), which has been associated with toxic cyanobacterial blooms (cyanoHABs). This study examines the seasonal factors influencing cyanoHABs in the Lake Pontchartrain Estuary when the BCS is closed, addressing gaps in the understanding of HABs related to other physical drivers. Field samples collected in 2021, during the closure of the spillway, revealed significant evidence of seasonal variations in cyanoHAB formation. …

Corrigendum: Diatom Transcriptional And Physiological Responses To Changes In Iron Bioavailability Across Ocean Provinces (Frontiers In Marine Science, (2017), 4, (360), 10.3389/Fmars.2017.00360), Natalie R. Cohen, Kelsey A. Ellis, Robert H. Lampe, Heather Mcnair, Benjamin S. Twining, Maria T. Maldonado, Mark A. Brzezinski, Fedor I. Kuzminov, Kimberlee Thamatrakoln, Claire P. Till, Kenneth W. Bruland, William G. Sunda, Sibel Bargu, Adrian Marchetti

Faculty Publications

In the published article, there was an error in Figure 3 as published. The initial (T0) phytoplankton community composition at site C2 was incorrectly displayed, with prasinophytes erroneously appearing as relatively abundant taxa. The corrected Figure 3 appears below. The average transcript proportions of phytoplankton taxa (outer charts) and diatom genera (inner charts) from initial seawater (T0) and during the first time point (T1; see Supplementary Table 1) within the Fe addition (Fe) and DFB addition (DFB) treatments at each site. Note that for site O5, the T2 control (Ctl) treatment is provided as the Fe-limited comparison. A text correction …

Petroleum Reservoir Dynamics, Mehdi Zeidouni

E-Textbooks

The book is structured into nine chapters, each designed to build a comprehensive understanding of reservoir engineering principles. Chapter 1 introduces the discipline and its connections with other areas of petroleum engineering. Chapters 2 through 5 address steady-state flow and its various complexities: Darcy’s equation and its limitations (Chapter 2); flow geometries and skin factor concepts (Chapter 3); compressible oil and gas flow (Chapter 4); and non-horizontal flow using the flow potential concept (Chapter 5).

In Chapter 6, the pressure diffusivity equation is explored alongside key concepts of radius of investigation and average reservoir pressure. Chapter 7 delves into the …

Is Verbal Rehearsal Strategic? An Investigation Into Overt Rehearsal Of Nameable Pictures In 5- To 10-Year-Old Children, Candice C. Morey, Angela M. Aubuchon, Meg Attwood, Thomas Castelain, Nelson Cowan, Davide Crepaldi, Emilie Fjerdingstad, Eivor Fredriksen, Chris Jarrold, Chris Koch, Jaroslaw R. Lelonkiewicz, Gary Lupyan, Whitney Mendenhall, David Moreau, Christina Schonberg, Christian K. Tamnes, Haley Vlach, Emily M. Elliott

Faculty Publications

Though verbal rehearsal is a frequently endorsed strategy for remembering short lists among adults, there is ambiguity around when children deploy it, and what circumstantial factors encourage them to rehearse. We recoded data from a recent multilab replication of a serial picture memory task in which children were observed for evidence of task-related speech or lip movements to extract finer-grained detail about how children spoke during the task. With these data, we aimed to better understand the manner in which children rehearse and the task scenarios which elicit overt rehearsal. Children in several countries from 5 to 10 years old …

Complex Models Of Sequence Evolution Improve Fit, But Not Gene Tree Discordance, For Tetrapod Mitogenomes, Benjamin S. Toups, Robert C. Thomson, Jeremy M. Brown

Faculty Publications

Variation in gene tree estimates is widely observed in empirical phylogenomic data and is often assumed to be the result of biological processes. However, a recent study using tetrapod mitochondrial genomes to control for biological sources of variation due to their haploid, uniparentally inherited, and non-recombining nature found that levels of discordance among mitochondrial gene trees were comparable to those found in studies that assume only biological sources of variation. Additionally, they found that several of the models of sequence evolution chosen to infer gene trees were doing an inadequate job of fitting the sequence data. These results indicated that …

The Iron Dice Of Battle: Albert Sidney Johnson And The Civil War In The West, Matthew Hulbert

Civil War Book Review

No abstract provided.

Louisiana Youth For Excellence (Lyfe): 2024 Data Collection & Technical Assistance Final Report, Elizabeth Winchester, Jada Thomas-Smith, Quynh-Tram Tran

Reports

Louisiana Youth for Excellence (LYFE) is a Sexual Risk Avoidance Education (SRAE) program funded by the U.S. Department of Health and Human Services, Administration for Children and Families. The program housed in the Governor’s Office targets youth ages 10-19. LYFE uses an evidence-based curriculum to equip youth with skills that promote positive youth development.

LYFE subgrantees reported program, participant, and administrative data during two collection periods: Winter 2024 and Summer 2025. LYFE subgrantees are required to submit data based on three performance indicators: 1) annual structure cost and support; 2) biannual attendance, reach and dosage; and 3) biannual participant characteristics, …

Concomitant Entanglement And Control Criticality Driven By Collective Measurements, Thomas Iadecola, Justin H. Wilson, J. H. Pixley

Faculty Publications

Adaptive quantum circuits - where a quantum many-body state is controlled using measurements and conditional unitary operations - are a powerful paradigm for state preparation and quantum error-correction tasks. They can support two types of nonequilibrium quantum phase transitions: measurement-induced transitions between volume- and area-law-entangled steady states and control-induced transitions where the system falls into an absorbing state or, more generally, an orbit visiting several absorbing states. Within this context, nonlocal conditional operations can alter the critical properties of the two transitions and the topology of the phase diagram. Here, we consider the scenario where the measurements are nonlocal, in …

Coupling Between Bacterial Phylogenetic Diversity And Heterotrophic Productivity In A Coastal Ecosystem Affected By Estuarine Plumes, Yao Liu, Shujie Cai, Wenxin Fan, Wupeng Xiao, Xin Liu, Edward A. Laws, Bangqin Huang

Faculty Publications

Understanding the diversity-productivity relationship (DPR) is crucial for elucidating the ecological functions of marine bacterioplankton. However, studies have often focused on species diversity, neglecting phylogenetic diversity, which may offer deeper insights into the complex ecological processes shaping DPR in natural systems. This study addressed this gap by exploring the role of phylogenetic diversity in bacterioplankton productivity in the northern South China Sea, a coastal ecosystem influenced by estuarine plumes. We aimed to disentangle the mechanisms driving DPR and investigate how estuarine plumes modulate these processes. Our results show that the substantial enhancement of phytoplankton production by the Pearl River plume …

Playing Politics With Traffic Fines: Sheriff Elections And Political Cycles In Traffic Fines Revenue, Min Su, Christian Buerger

Faculty Publications

The political budget cycle theory has extensively documented how politicians manipulate policies during election years to gain an electoral advantage. This paper focuses on county sheriffs, crucial but often neglected local officials, and investigates their opportunistic political behavior during elections. Using a panel data set covering 57 California county governments over four election cycles, we find compelling evidence of traffic enforcement policy manipulation by county sheriffs during election years. Specifically, a county's per capita traffic fines revenue is 9% lower in the election than in nonelection years. The magnitude of the political cycle intensifies when an election is competitive. Our …