Digital Commons Network^™

Elucidating Factors Affecting Cercosporin Production In Cercospora Leaf Blight Of Soybean To Develop Better Tools For Disease Management, Maria Izabel Costa De Novaes

LSU Doctoral Dissertations

Fungal toxins are pathogenicity/virulence factors for many plant diseases, including Cercospora leaf blight (CLB) of soybean (Glycine max (L.) Merr.). The pathogen, Cercospora cf. flagellaris, produces a perylenequinone toxin, cercosporin, which is activated by light to produce damaging reactive oxygen species. To identify novel solutions for CLB management, we studied factors that may impact the biology of cercoporin: fungal lipid droplets (LDs) and mineral and trace element composition (ionome) of the host. Furthermore, since artificial inoculation with the pathogen has been challenging, we also explored the usefulness of a previously developed cercosporin-based assay to study disease resistance. LDs …

Investigating Preferences And Behavior Within Environmental Economics, Sapana Bastola

LSU Doctoral Dissertations

To respond to the environmental problems posed by disposable plastic bags, several mechanisms exist, such as bag taxes and bans, but such policies are infeasible in several U.S. states and municipalities. This study uses a social quasi-experiment to examine the effect of a voluntary token-donation program, which reduces disposable plastic bag use by providing a small charitable donation incentive. We find that the token-donation program reduces the probability of disposable bag use by 11.4–12.9 percentage points, representing about a 30%–34% decrease in bag use. Our results demonstrate effective mechanisms to reduce plastic bags exist without government-mandated policy.

Despite the widespread …

Hexavalent Chromium Increases The Metabolism And Genotoxicity Of Aromatic Amine Carcinogens 4-Aminobiphenyl And Β-Naphthylamine In Immortalized Human Lung Epithelial Cells, James T.F. Wise, Raúl A. Salazar-González, Kennedy M. Walls, Mark A. Doll, Mariam R. Habil, David W. Hein

Faculty Publications

Humans are exposed to carcinogenic chemicals via occupational and environmental exposures. Common chemicals of concern that can occur in exposures together are aromatic amines (e.g., 4-aminobiphenyl [4-ABP] and β-naphthylamine [BNA]) and hexavalent chromium (Cr[VI]). Arylamine N-acetyltransferases 1 and 2 (NAT1 and NAT2) are key to the metabolism of aromatic amines and their genotoxicity. The effects of Cr(VI) on the metabolism of aromatic amines remains unknown as well as how it may affect their ensuing toxicity. The objective of the research presented here is to investigate the effects of Cr(VI) on the metabolism and genotoxicity of 4-ABP and BNA in immortalized …

Effects Of Pesticides On Red Rot Of Sugarcane, Kezia Cristina Da Silva Reis

LSU Master's Theses

Red rot disease of sugarcane, caused by Colletotrichum falcatum, can be an important constraint to crop production. In Louisiana, red rot primarily affects seed-cane and is more severe when billets (stalk sections) are planted rather than whole-stalks. At planting application of seed-treatment chemicals, particularly a combination of fungicide and thiamethoxam insecticide, has improved stand establishment and increased yields in billet plantings in Louisiana. However, information has been lacking on the effect of the treatments on disease development. Greenhouse experiments were conducted in 2020 and 2021 to evaluate stalk rot symptom severity and initial plant growth for billets dip-treated with …

Comparative Genomics And Virulence Studies Of Streptomyces Soil Rot And Scab Pathogen Species, Natasha Soares

LSU Doctoral Dissertations

Comparative genomic analyses were performed to gain insights into the organization and content of the genome of Streptomyces ipomoeae, the soil rot pathogen that infects sweetpotatoes. Unlike Streptomyces scab pathogens, the thaxtomin phytotoxin gene cluster (txt) in S. ipomoeae does not appear to reside within a genomic island and has diverged from its scab pathogen counterparts. Increased usage of the rare TTA codon, particularly for the txt cluster, suggests greater translational control by the bldA tRNA in S. ipomoeae. Orthologous gene searches and secondary metabolite profiling yielded ortholog groups and metabolite gene clusters that were exclusive …

The Effects Of Exercise On Innate Lymphoid Cell Metabolism And Function In Cancer, Eunhan Cho

LSU Doctoral Dissertations

Immunosenescence refers to the gradual decrease in immune competency over time, which is strongly associated with increased risk of cancer and a rise in morbidity and mortality among the elderly. Regular physical activity can be beneficial to the immune system by potentially decreasing the frequency of senescent immune cells and reducing mortality risk in cancer patients and survivors. However, less is known on the impact of acute exercise on “aggressive” cancers, such as hormone receptor negative breast cancers. Further, the mechanistic underpinnings of the exercise-associated improvements in the immune response to cancer remains unclear. In this context, past studies have …

"I'M Not Your Ride Or Die": A Qualitative Study Of Black Women's Experiences In Intimate Marketplaces, Alana Jamelle Peck

LSU Doctoral Dissertations

Black women’s marriage rates have consistently been on the decline since the 1960’s and currently, Black women are the least likely to get married across all races and genders (Bureau 2020). Scholars have been using these statistics to tell monolithic narratives of Black womanhood, and even blame Black women for larger issues within the Black community (Collins 2000, Johnson and Loscocco 2015; Moynihan 1965). Prior scholars have also attempted to provide solutions to this problem, while never even approaching Black women, to suggest ways that they can increase their marriage rates and consequently uplift Black families and the Black community …

Longitudinal Associations Between Housing Instability, Primary Caregiver's Mental Health, Parenting Skills, And Child Behavior Problems: A Latent Growth Modeling Approach, Xi Du

LSU Doctoral Dissertations

Children who grow up in disruptive environments have heightened vulnerability to psychological and behavioral difficulties, which may influence overall well-being through the course of their lives. This study combined a life course perspective with Conger’s family stress model to investigate the longitudinal associations between housing instability, primary caregiver’s mental health, parenting skills, and child internalizing/externalizing behavior problems by unpacking dynamic change from a focal child’s early childhood to adolescence in each factor.

Data came from the Panel Study of Income Dynamics and its Child Development Supplement survey. The analytic sample comprises 783 children who aged 3-7 at enrollment with consistent …

Computational Imaging For Shape Understanding, Yuqi Ding

LSU Doctoral Dissertations

Geometry is the essential property of real-world scenes. Understanding the shape of the object is critical to many computer vision applications. In this dissertation, we explore using computational imaging approaches to recover the geometry of real-world scenes. Computational imaging is an emerging technique that uses the co-designs of image hardware and computational software to expand the capacity of traditional cameras. To tackle face recognition in the uncontrolled environment, we study 2D color image and 3D shape to deal with body movement and self-occlusion. Especially, we use multiple RGB-D cameras to fuse the varying pose and register the front face in …

Incorporating Geopolymer Binders To Fully Utilize Recycled Concrete Aggregates, Matthew Upshaw

LSU Doctoral Dissertations

This study aims to develop a geopolymer concrete binder that will yield desirable strength and durability characteristics when applied to recycled aggregate concrete. In order to achieve this, a geopolymer binder consisting of a metakaolin-silica fume aluminosilicate source material blend activated by potassium-based alkaline solutions is developed and used in place of ordinary Portland cement (OPC) with four different levels of recycled aggregate replacement ratios. The properties of these concretes were analyzed and compared with the properties of OPC concretes produced with the same replacement ratio levels. The results showed that the geopolymer recycled aggregate concrete (GRAC) achieved greater than …

Improved Building-Specific Flood Risk Assessment And Implications Of Depth-Damage Function Selection, Ehab Gnan, Carol J. Friedland, Md Adilur Rahim, Rubayet Bin Mostafiz, Robert V. Rohli, Fatemeh Orooji, Arash Taghinezhad, Jasmin Mcelwee

Faculty Publications

Average annual loss (AAL) is traditionally used as the basis of assessing flood risk and evaluating risk mitigation measures. This research presents an improved implementation to estimate building-specific AAL, with the flood hazard of a building represented by the Gumbel extreme value distribution. AAL is then calculated by integrating the area under the overall loss-exceedance probability curve using trapezoidal Riemann sums. This implementation is compared with existing AAL estimations from flood risk assessment. A sensitivity analysis is conducted to examine the variability in AAL results based on depth-damage function (DDF) choice. To demonstrate the methodology, a one-story single-family residence is …

Covid-19 In The United States As Affective Frame, John Protevi

Faculty Publications

In this paper I attempt to contribute to the developing field of “political philosophy of mind.” To render concrete the notion of “affective frame,” a social situation which pre-selects for salience and valence of environmental factors relative to a subject’s life, I conduct a case study of a deleterious socially instituted affective frame, which, during the early days of the COVID19 pandemic in the United States, produced individuated circumstances that came crashing down on “essential workers” who were forced into a double bind. We saw here an untenable and ultimately fatal situation that forced a choice between, on the one …

Insight In Thermomechanical Constitutive Modeling Of Shape Memory Polymers, Amir Shojaei, Wei Xu, Cheng Yan, Qianxi Yang, Guoqiang Li

Faculty Publications

Shape memory polymers (SMPs) are a new member of the smart materials family. SMPs have found wide applications or potential applications in almost all manmade structures and devices. In order to better design smart structures and devices using SMPs, thermomechanical constitutive modeling is essential. In this insight paper, we will focus on presenting several multi-length-scale and multi-physics modeling frameworks, including the thermodynamics consistent model, elasto-viscoplastic model, statistical mechanics model, and phase evaluation law model. The SMPs modeled will include amorphous one-way shape memory polymers, semicrystalline one-way shape memory polymers, semicrystalline two-way shape memory polymers, and functional and mechanical damage effects …

The Effects Of Drought And Shade On Bottomland Hardwood Regeneration, Charles Joseph Pell

LSU Doctoral Dissertations

Floodplain forests support a high diversity of tree species adapted to regenerate under fluctuating water and light availability. Regeneration regulates species composition, and shade and flood tolerance influence the likelihood of regeneration. Regeneration failure of shade-intolerant and flood-tolerant tree species commonly occurs in southcentral and southeastern floodplain forests of the United States, also known as bottomland hardwoods (BLHs). In many BLHs reduced flooding has resulted in a dryer floodplain. These changes in flooding are linked to recent shifts in species composition. The mechanisms controlling regeneration in BLHs and these composition shifts are poorly understood. In a controlled germination experiment, I …

Application Of Organic Fertilizers For Lawn Establishment And Maintenance In Louisiana, Matthew Lambert

LSU Master's Theses

Landscape contractors are increasingly interested in organic products for Louisiana's residential and commercial turfgrass areas. However, the use, motivations, and barriers to adopting organic practices in the commercial turfgrass and landscape industry are undocumented. A survey with Louisiana Turfgrass Association (LTA) members to gauge their perceptions on current and future use of organic products in Louisiana was performed; and a field trial was conducted to evaluate organic fertilizers during turfgrass establishment. Substantial majorities of turfgrass professionals are currently applying organic fertilizers and believe organic product use will increase due to consumer demands, potential governmental regulation, and the belief that they …

Evaluating Serverless Computing, Charitra Maharjan

LSU Master's Theses

Function as a Service (FaaS) is gaining admiration because of its way of deploying the computations to serverless backends in the different clouds. It transfers the complexity of provisioning and allocating the necessary resources for an application to the cloud providers. The cloud providers also give an illusion of always availability of resources to the users. Among the cloud providers, AWS serverless platform offers a new paradigm for developing cloud applications without worrying about the underlying hardware infrastructure. It manages not only the resource provisioning and scaling of an application but also provides an opportunity to reimagine the cloud infrastructure …

The Association Of Cuzd1 And Stat5 In Adipocytes, Zachary Wigger

LSU Master's Theses

Obesity is a metabolic disorder that has turned into a global epidemic over the past few decades. Adipocyte dysfunction brought on by obesity can lead to increased risk of metabolic diseases such as cardiovascular disease and type 2 diabetes mellitus (T2DM). Knowing how adipocytes function to regulate metabolic homeostasis is critical. CUZD1 (CUB and Zona Pellucida-like Domain-containing protein 1) has not been studied in the context of adipocyte biology but could play a role in several metabolic processes. CUZD1 has been suggested to be a biomarker for several inflammatory diseases and cancers but little functional data has been published. There …

Ultraviolet Chiral Plasmonics, Tiago Ramos Leite Da Silva

LSU Doctoral Dissertations

The far- (λ < 250 nm) ultraviolet (UV) chiroptical response from protein secondary structures can aid in understanding protein interactions for drug discovery. Chiral metasurfaces have attracted attention to enhance the intrinsically weak biomolecular optical activity for improved structural biology characterization. However, due to materials and fabrication challenges, current metasurfaces mostly operate in the visible and near-infrared regimes with limited, if any, response in far-UV. The large spectral mismatch between metasurface and biomolecular resonances limits the chiral enhancement factor. In this work, we study aluminum planar metamaterials which display optical activity in the UV region. In the first part of this work, we experimentally and computationally investigate the resonant plasmonic-biomolecular interactions in the far-UV. To the best of our knowledge, our work is the first to experimentally explore these resonant interactions in the biologically relevant far-UV regime. We demonstrate experimentally and computationally enhanced chiral sensing of sub-10 nm amino acid films. We develop a full-wave computational model of a biomolecular film on an aluminum gammadion array using experimentally derived chiral parameters (κ) for L- and DTyrosine films. Our model shows that detectable enhancements in the circular dichroism (CD) and birefringence (CB) signals from small amounts of biomolecules are only possible when tight spectral overlap exists between the plasmonic and biomolecular chiroptical signals. We support this conclusion experimentally by fabricating aluminum gammadion arrays on fused silica substrates and sublimating ultrathin racemic, L- and D- Tyrosine films on the arrays. Complete Mueller matrix analysis of the resonant plasmonic-biomolecular system agrees with our computational results and demonstrates the importance of using far-UV active metasurfaces for enhancing natural optical activity. In the second part of this work, we study hybrid aluminum reflective metasurfaces, which leverage both local and propagating surface plasmons (PSP). These materials display strong bi-anisotropy with rich polarization conversion properties. We explore several geometries and verify how their symmetry properties affect their far-field response. Our observations provide an opportunity for researchers to improve the chiral response of plasmonic metasurfaces, especially in the challenging ultraviolet regime.

Supplemental Nutrition Assistance Program (Snap)-Authorised Store Marketing Environments In Louisiana Encourage The Selection Of Less Nutritious Foods And Beverages, Bailey Houghtaling, Melissa Cater, Nila Pradhananga, Denise Holston

Faculty Publications

Marketing influences consumers’ dietary purchases. However, little is known about marketing environments in Supplemental Nutrition Assistance Program (SNAP)-authorised stores. The present study explored SNAP-authorised store marketing environments in Louisiana by rurality, store ownership and store type (n 42). Sampling methods were designed to include randomly selected stores in each geographic area of the state. The GroPromo was used to measure placement, promotion, and child-focused aspects of marketing strategies used for healthier (fruits and vegetables) and less healthy products (chips, candy, sugar-sweetened beverages, child-focused cereal) in medium- and high-prominence marketing areas. In using multivariate analysis of variance (MANOVA) (P < 0⋅05) for data analysis, variations in GroPromo scores were found among SNAP-authorised stores by rurality (P < 0⋅05) and store ownership (P < 0⋅001); no differences were found by store type (P > 0⋅05). Future …

Hydrodynamic And Biochemical Impacts On The Development Of Hypoxia In The Louisiana-Texas Shelf - Part 2: Statistical Modeling And Hypoxia Prediction, Yanda Ou, Bin Li, Z. George Xue

Faculty Publications

This study presents a novel ensemble regression model for forecasts of the hypoxic area (HA) in the Louisiana-Texas (LaTex) shelf. The ensemble model combines a zero-inflated Poisson generalized linear model (GLM) and a quasi-Poisson generalized additive model (GAM) and considers predictors with hydrodynamic and biochemical features. Both models were trained and calibrated using the daily hindcast (2007-2020) by a three-dimensional coupled hydrodynamic-biogeochemical model embedded in the Regional Ocean Modeling System (ROMS). Compared to the ROMS hindcasts, the ensemble model yields a low root-mean-square error (RMSE) (3256 km2), a high R2 (0.7721), and low mean absolute percentage biases for overall (29%) …

Organic Matter And Nutrient Cycling In Coastal Wetlands And Submerged Aquatic Ecosystems In An Age Of Rapid Environmental Change—The Anthropocene, Tracy Elsey-Quirk, Jeffrey C. Cornwell

Faculty Publications

No abstract provided.

A New Ocean State After Nuclear War, Cheryl S. Harrison, Tyler Rohr, Alice Duvivier, Elizabeth A. Maroon, Scott Bachman, Charles G. Bardeen, Joshua Coupe, Victoria Garza, Ryan Heneghan, Nicole S. Lovenduski, Philipp Neubauer, Victor Rangel, Alan Robock, Kim Scherrer, Samantha Stevenson, Owen B. Toon

Faculty Publications

Nuclear war would produce dire global consequences for humans and our environment. We simulated climate impacts of US-Russia and India-Pakistan nuclear wars in an Earth System Model, here, we report on the ocean impacts. Like volcanic eruptions and large forest fires, firestorms from nuclear war would transport light-blocking aerosols to the stratosphere, resulting in global cooling. The ocean responds over two timescales: a rapid cooling event and a long recovery, indicating a hysteresis response of the ocean to global cooling. Surface cooling drives sea ice expansion, enhanced meridional overturning, and intensified ocean vertical mixing that is expanded, deeper, and longer …

Global Food Insecurity And Famine From Reduced Crop, Marine Fishery And Livestock Production Due To Climate Disruption From Nuclear War Soot Injection, Lili Xia, Alan Robock, Kim Scherrer, Cheryl S. Harrison, Benjamin Leon Bodirsky, Isabelle Weindl, Jonas Jägermeyr, Charles G. Bardeen, Owen B. Toon, Ryan Heneghan

Faculty Publications

Atmospheric soot loadings from nuclear weapon detonation would cause disruptions to the Earth’s climate, limiting terrestrial and aquatic food production. Here, we use climate, crop and fishery models to estimate the impacts arising from six scenarios of stratospheric soot injection, predicting the total food calories available in each nation post-war after stored food is consumed. In quantifying impacts away from target areas, we demonstrate that soot injections larger than 5 Tg would lead to mass food shortages, and livestock and aquatic food production would be unable to compensate for reduced crop output, in almost all countries. Adaptation measures such as …

Numerical Experiments Of Temperature Mixing And Post-Storm Re-Stratification Over The Louisiana Shelf During Hurricane Katrina (2005), Mohammad Nabi Allahdadi, Chunyan Li, Nazanin Chaichitehrani

Faculty Publications

Studying mixing and re-stratification during and after hurricanes have important implications for the simulation of circulation and bio-geochemical processes in oceanic and shelf waters. Numerical experiments using FVCOM on an unstructured computational mesh were implemented to study the direct effect of hurricane winds on the mixing and temperature redistribution of the stratified Louisiana shelf during Hurricane Katrina (2005), as well as the post-storm re-stratification timescale. The model was forced by Katrina’s wind stress obtained from a combination of H-Wind database and NCEP model. The climatological profiles of temperature and salinity for August (the month in which Katrina occurred) from the …

Profile Of Commercialized Aphicides On The Survivorship And Feeding Behavior Of The Cotton Aphid, Aphis Gossypii, Flinn M. O'Hara, Jeffrey A. Davis, Daniel R. Swale

Faculty Publications

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is one of the most destructive agricultural pests due to photosynthate removal and horizontal transmission of plant viruses. Horizontal transmission of plant viruses by aphids occurs during distinct feeding behavioral events, such as probing for non-persistent viruses or phloem feeding for persistent viruses. We employed toxicity bioassays and electrical penetration graph (EPG) methodology to compare toxicity and quantify changes to feeding behavior and toxicity of A. gossypii after exposure to commercialized aphicides. Commercialized aphicides containing flupyradifurone, sulfoxaflor, thiamethoxam, thiamethoxam + lambda cyhalothrin, and bifenthrin induced >90% aphid mortality within 4 h of …

Canopy Arthropod Responses To Repeated Canopy Opening In A Wet Tropical Forest, Manoj Pandey, Timothy D. Schowalter

Faculty Publications

With predictions of increased frequency of intense hurricanes, it is increasingly crucial to understand how biotic and abiotic components of forests will be affected. This study describes canopy arthropod responses to repeated experimental and natural canopy opening at the Luquillo Experimental Forest Long-term Ecological Research Site (LTER) in Puerto Rico. The canopy trimming experiment (CTE1) treatments were started in 2004, and a second trimming (CTE2) was conducted in 2014, to study effects of increased hurricane frequency at the site. Paired disturbed plots with canopy trimmed (trim) and undisturbed plots with no trimming (no trim) were replicated in three experimental blocks. …

Evaluation Of Fresh And Hardened Properties Of 3d-Printed Engineered Cementitious Composites (Ecc) Designed For Sustainable And Resilient Infrastructure Systems, Maryam Hojati, Muhammad Saeed Zafar, Amir Bakhshi

Data

3D concrete printing is a cutting-edge construction technique that has the potential to revolutionize the construction industry due to cost-saving in terms of labor and formwork costs, efficiency in construction, lower safety-related risks, and a higher degree of automation. However, several issues still make its adoption relatively slower on a large scale. Engineered cementitious composites (ECC), a class of ultra-high-strength concrete, can be a potential solution to some problems, such as reinforcement and durability. The preliminary phase of a Tran SET project focused on the design of 3D printable ECC, considering the concrete mix design proportions and their potential effects …

Evaluation Of Fresh And Hardened Properties Of 3d-Printed Engineered Cementitious Composites (Ecc) Designed For Sustainable And Resilient Infrastructure Systems, Maryam Hojati, Muhammad Saeed Zafar, Amir Bakhshi

Publications

3D concrete printing is a cutting-edge construction technique that has the potential to revolutionize the construction industry due to cost-saving in terms of labor and formwork costs, efficiency in construction, lower safety-related risks, and a higher degree of automation. However, several issues still make its adoption relatively slower on a large scale. Engineered cementitious composites (ECC), a class of ultra-high-strength concrete, can be a potential solution to some problems, such as reinforcement and durability. The preliminary phase of a Tran SET project focused on the design of 3D printable ECC, considering the concrete mix design proportions and their potential effects …

Alternative Supplementary Cementitious Materials In Ultra-High Performance Concrete, Craig Newtson, Seyedsaleh Mousavinezhad, Gregory J, Gonzales, William K. Toledo, Judit M. Garcia

Data

Ultra-high performance concrete (UHPC) is an emerging material with remarkable mechanical and durability properties that contains large amounts of cementitious materials. Silica fume is a main supplementary cementitious material (SCM) in UHPC, however, it is more expensive than cement and other SCMs, so it is often substituted with inexpensive class F fly ash. Unfortunately, future availability of fly ash is uncertain as the energy industry moves toward renewable energy. Fly ash shortages create an urgent need to find cost-effective and environmentally-friendly alternatives for fly ash. This study investigated replacing cement, fly ash, and silica fume in UHPC mixtures with ground …

Effectiveness Assessment Of E-Ticketing Technology In Construction Of Transportation Projects, Sharareh Kermanshachi, Karthik Subramanya

Data

The construction of highway infrastructure has devoted significant resources towards e-Construction to reduce the paperwork and automate the tasks in daily operations. Electronic Ticketing (e-Ticketing) is one such component of e-Construction that aids in the digital transfer of material tickets such as asphalt and concrete which accounts for more than fifty per cent of construction costs. Despite the benefits of e-Ticketing, many state departments and agencies are unwilling to transition into this technology. No studies have identified the cause of the delay in the implementation process, developed a framework to comprehend the platform's full potential, quantified savings, and suggested strategies …