Digital Commons Network^™

Climate From The Mcmurdo Dry Valleys, Antarctica, 1986–2017: Surface Air Temperature Trends And Redefined Summer Season, M. K. Obryk, P. T. Doran, A. G. Fountain, M. Myers, C. P. Mckay

Faculty Publications

©2020. American Geophysical Union. All Rights Reserved. The weather of the McMurdo Dry Valleys, Antarctica, the largest ice-free region of the Antarctica, has been continuously monitored since 1985 with currently 14 operational meteorological stations distributed throughout the valleys. Because climate is based on a 30-year record of weather, this is the first study to truly define the contemporary climate of the McMurdo Dry Valleys. Mean air temperature and solar radiation based on all stations were −20°C and 102 W m−2, respectively. Depending on the site location, the mean annual air temperatures on the valleys floors ranged between −15°C and −30°C, …

The Collection Of Baseline Data On Insect And Plant Communities Across Multiple Salinity Zones Within Louisiana's Tidal Marshes, Benjamin G. Aker

LSU Master's Theses

Tidally influenced coastal marshes provide numerous important ecosystem services, but these habitats are experiencing extreme habitat loss. Louisiana’s coastal marshes in particular are vulnerable to land loss resulting from both anthropogenic and natural causes, but especially to subsidence and relative sea-level rise. In response, the Louisiana Coastal Restoration and Protection Authority has outlined and is currently implementing the largest ever attempt at habitat restoration. A major component of this habitat restoration attempt is the use of freshwater and sediment diversions to increase the input of low salinity water, sediment, and nutrients needed to slow marsh loss and build land. Coastal …

Protestant Experience And Continuity Of Political Thought In Early America, 1630-1789, Stephen Michael Wolfe

LSU Doctoral Dissertations

The debate on the continuity of American political thought from the 17^th century Puritan settlements to the 18^th century American founding assumes a bipolar spectrum, ranging from strong continuity to strong discontinuity. The degree that scholars recognize distinctively Christian, theological, or Protestant ideas operating in the founding era determines where they are placed on the spectrum. The most popular view today is the “amalgam” thesis, which is a moderate view, resulting from decades of debate. Amalgam theorists argue that the founders' political theory relied on a variety of sources, from classical to Protestant. The current debate centers on …

Mukhanov-Sasaki Equation In A Manifestly Gauge-Invariant Linearized Cosmological Perturbation Theory With Dust Reference Fields, Kristina Giesel, Laura Herold, Bao Fei Li, Parampreet Singh

Faculty Publications

The aim of this article is to understand the role of dust reference fields, often also called clocks, on cosmological perturbations around a classical spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) universe. We derive the Mukhanov-Sasaki equation for the Brown-Kuchař and Gaussian dust models, which both consider four dust fields as reference fields. The reduced phase space of Dirac observables, that is the gauge-invariant part of the theory, is constructed by means of an observable map applied to all elementary phase space variables of the coupled system, consisting of gravity, a massive scalar field and the dust degrees of freedom and automatically yields …

Saltmarsh Sustainability Throughout The Holocene In Boston Harbor: A New Sea-Level Curve For The Lower Gulf Of Maine And Implications Of Recent Anthropogenic Alteration, C. A. Wilson, Z. J. Hughes, D. M. Fitzgerald, A. S. Kolker, J. C. Lynch, P. Rosen

Faculty Publications

Saltmarsh evolution is closely linked to sea-level rise (SLR) and sediment supply. In a regime of accelerating SLR, saltmarsh survival depends on the ability of the marsh platform to grow vertically through organic and inorganic accumulation, and laterally via transgression over adjacent uplands. In formerly glaciated settings, the formation and maintenance of a saltmarsh are complicated by steep uplands, low sediment availability, isostatic rebound, changes to tidal amplitudes, and anthropogenic alteration. While much work has examined the development of large saltmarshes in New England since the mid-Holocene and Anthropocene, little is known about the smaller isolated saltmarshes that form in …

First-Principles Simulations Of X-Ray Transient Absorption For Probing Attosecond Electron Dynamics, Min Chen, Kenneth Lopata

Faculty Publications

Copyright © 2020 American Chemical Society. X-ray transient absorption spectroscopy (XTAS) is a promising technique for measuring electron dynamics in molecules and solids with attosecond time resolutions. In XTAS, the elemental specificity and spatial locality of core-to-valence X-ray absorption is exploited to relate modulations in the time-resolved absorption spectra to local electron density variations around particular atoms. However, interpreting these absorption modulations and frequency shifts as a function of the time delay in terms of dynamics can be challenging. In this paper, we present a first-principles study of attosecond XTAS in a selection of simple molecules based on real-time time-dependent …

Reaching 1.5 And 2.0 °C Global Surface Temperature Targets Using Stratospheric Aerosol Geoengineering, Cheryl Harrison

Faculty Publications

Abstract. A new set of stratospheric aerosol geoengineering (SAG) model experiments has been performed with Community Earth System Model version 2 (CESM2) with the Whole Atmosphere Community Climate Model (WACCM6) that are based on the Coupled Model Intercomparison Project phase 6 (CMIP6) overshoot scenario (SSP5-34-OS) as a baseline scenario to limit global warming to 1.5 or 2.0 ∘C above 1850–1900 conditions. The overshoot scenario allows us to applying a peak-shaving scenario that reduces the needed duration and amount of SAG application compared to a high forcing scenario. In addition, a feedback algorithm identifies the needed amount of sulfur dioxide injections …

Pressure Monitoring For Subsurface Leakage Characterization, Mojtaba Mosaheb

LSU Doctoral Dissertations

Undesirable leakage from underground sedimentary formations is a matter of considerable concern due to implications for water resources contamination and greenhouse gas emissions. Leakage in underground formations can remain undetected for a long period. Pressure monitoring is a dynamic method that can be used for leakage detection and characterization. The pressure signals are affected by the hydraulic characteristics of the reservoir media and leakage pathways. Consequently, the pressure data can be interpreted to obtain information about the hydraulic characteristics of the system. Pressure interpretation is useful for early leakage detection, because the pressure signals travel fast in reservoir media. In …

Habitat Fragmentation And Range Margin Effects On Dispersal And Interactions Between Competitors, Rachel Roxann Harman

LSU Doctoral Dissertations

Dispersal is a fundamental process that affects local and regional dynamics, including population persistence, range expansion, and interspecific interactions, particularly as disturbance through habitat fragmentation and climate change. Here, my main objective was to ascertain how fragmentation affects dispersal and the interactions of competitors within the local patch and regional landscape. In my second chapter, I assessed dispersal through a literature review and population persistence model to examine the breadth and frequency of different density-emigration forms that occur in nature, including forms that are not prevalent in the literature. I conclude that these rare forms have important population dynamic consequences …

Ecology Of The Roseau Cane Scale (Nipponaclerda Biwakoensis, Hemiptera: Aclerdidae) In Coastal Louisiana, Leslie Alejandra Aviles Lopez

LSU Master's Theses

Common reed, Phragmites australis, is the dominant plant in the Mississippi River Delta (MRD), Louisiana. Phragmites australis stands reduce soil erosion from wave action, protect the oil infrastructure, and freshwater habitats. In the fall of 2016, widespread reed die-backs in the MRD were associated with outbreaks of an invasive scale Nipponaclerda biwakoensis (Hemiptera: Aclerdidae). Due to the recent detection of the scale, there was limited knowledge of its ecology in the adventive range, and its impacts on P. australis lineages. Therefore, the objectives of my thesis were to determine (1) the host specificity of the N. biwakoensis in important economic …

Study On The Chemical And Mechanical Stability Of Polymer Nanofluidic Biosensors, Dae Won Kim

LSU Master's Theses

Polymer nanofluidic devices have great potential to replace silicon (Si) and glass-based nanofluidic devices in biomedical applications due to their advantages such as low material and fabrication cost, various physicochemical properties, well-developed surface modification protocol, and low electrical noises for electrical measurements. In nanofluidic sensing applications, single molecules such as DNA are introduced into the fabricated nanochannel or nanopore, measuring their physicochemical properties optically or electrically. The properties of materials for nanofluidic devices have a significant role in the performance of the devices, such as DNA translocation and device stability.

Among several nanoscale fluidic physics, surface charge density is a …

The Effect Of Aircraft Manufacturing Riveting Tools On Hand-Arm Vibrations And Muscle Fatigue, Lou Toua Vi

LSU Master's Theses

The overall objective of this research was to compare four types of rivet guns varying by manufacturer and piston material (Tungsten vs. Steel), two rivet gun handle positions (Horizontal and Vertical), and three bucking bars including two with similar dimensions bars made of tungsten and steel, and a Honsa new technology spring dampener and tungsten combined bucking bar based on their impact on hand-arm vibrations and the effect of these vibration levels on muscle fatigue. This objective was covered in three parts. The first part consisted of examining the impact of these factors on riveters’ vibration exposure and muscle fatigue, …

Hydraulic Effects Of The Lower Mississippi River Batture, David P. May

LSU Master's Theses

The Lower Mississippi River (LMR), since the creation of the Mississippi River and Tributaries (MR&T) project, has been extensively modified to support navigation and flood risk reduction. The components of the MR&T system, implemented to support the above missions, have performed successfully for many decades, but not without contention. Rising stages in recent years have led to the questioning of the hydraulic impact of navigation dikes and river training methodologies. Multiple studies have been performed (Biedenharn, 2000, May 2017, Mayne, 2018, and Simon, 2019) that indicate these river training structures have minimal impact to stage during flood conditions. It has …

Detecting Fitness Epistasis In Recently Admixed Populations With Genome-Wide Data, Xumin Ni, Mengshi Zhou, Heming Wang, Karen Y. He, Uli Broeckel, Craig Hanis, Sharon Kardia, Susan Redline, Richard S. Cooper, Hua Tang, Xiaofeng Zhu

Faculty Publications

Background: Fitness epistasis, the interaction effect of genes at different loci on fitness, makes an important contribution to adaptive evolution. Although fitness interaction evidence has been observed in model organisms, it is more difficult to detect and remains poorly understood in human populations as a result of limited statistical power and experimental constraints. Fitness epistasis is inferred from non-independence between unlinked loci. We previously observed ancestral block correlation between chromosomes 4 and 6 in African Americans. The same approach fails when examining ancestral blocks on the same chromosome due to the strong confounding effect observed in a recently admixed population. …

Contribution Of Velocity Congruency And Apparent Stiffness To Interference Of Bimanual Rhythmic-Discrete Movements., Marcelline E. Dechenaud

LSU Master's Theses

Many actions feature rhythmic and discrete movements, individually or in combinations. Rhythmic movements are defined as those having no clearly defined start and end-point, while discrete movements have a definite starting and ending posture. Performing a discrete movement against a base rhythm by the contralateral limb typically speeds up the rhythmic movement -- indicating the presence of bimanual coupling. While bimanual rhythmic/rhythmic interaction has been studied extensively in the field, understanding of the interaction between discrete and rhythmic movements has been less represented. In this thesis, I examined two potential sources of interlimb interference during rhythmic-discrete bimanual actions: 1) velocity …

Solvation Structures And Dynamics Of Small Molecules: Experimental And Computational Studies Using Carbonyl Vibrational Modes As Probe, Xiaoliu Zhang

LSU Doctoral Dissertations

Solutions are ubiquitous in both the global environment and the human body, and play a significant role in scientific research and industrial production. The structures and dynamics of solutions have been studied for centuries. However, conventional experimental methods, whose intrinsic measuring time is on the order of nanoseconds to microseconds, could not detect the fast dynamics taking place in the solution on the timescale of femto- and pico-second. In this dissertation, the ultrafast two-dimensional infrared (2DIR) spectroscopy was applied to characterize the structure and dynamics in three different types of solutions on the sub-picosecond timescale. Linear Fourier transform infrared spectroscopy …

Polymeric Nanoparticles As An Antioxidant Delivery System For Age-Related Eye Disease, Sean M. Swetledge

LSU Doctoral Dissertations

Advantages of polymeric nanoparticles as ocular drug delivery systems include controlled release, enhanced drug stability and bioavailability, and specific tissue targeting. Nanoparticle properties such as hydrophobicity, size, and charge, mucoadhesion, as well as administration route and suspension media affect their ability to overcome ocular barriers and distribute in the eye, and must be carefully designed for specific target tissues and ocular diseases. A review was conducted to serve as a guide to optimizing polymeric nanoparticle delivery systems for ocular drug delivery by discussing the effects of nanoparticle composition and administration method on their ocular penetration, distribution, elimination, toxicity, and efficacy, …

Plant And Soil Responses To Sediment Deposition And Nutrient Enrichment In Healthy, Deteriorating, And Newly Created Coastal Marshes In Barataria Basin, Louisiana: Implications For Mississippi River Sediment Diversions, Gina N. Groseclose

LSU Master's Theses

To offset wetland loss in the Mississippi River Delta, sediment diversions that will re-introduce river water and sediment into wetlands are being planned for the lower Mississippi River. River diversions will also deliver high nutrient loads, which may reduce belowground plant productivity, reducing inputs of organic matter important for marsh accretion to keep pace with sea-level rise. However, belowground productivity responses to the combinatory effects of sediment and nutrients are unknown. To test the hypotheses that nutrient enrichment and sediment deposition interact to influence vegetation structure, belowground plant productivity and decomposition, and surface accretion, a field experiment was implemented in …

Generalizability Of Multiple Measures Of Treatment Integrity: Response Card Intervention, Elizabeth Kelsey Wilson

LSU Doctoral Dissertations

Treatment integrity is essential for the implementation of interventions in schools as it determines the accuracy or consistency with which different components of a treatment are implemented. There are no current standards regarding the best practices in treatment integrity measurement; however, higher treatment integrity is associated with enhanced student outcomes. At present, there is no database that provides information related to treatment integrity for practitioners, researchers, and policy-makers to reference when choosing an appropriate level of treatment integrity needed for a given intervention. Consequently, there is a need to establish convergent validity among different methods of treatment integrity measurement using …

Some Results On Seymour’S Second-Neighborhood Conjecture And On Decompositions Of Graphs, Farid Bouya

LSU Doctoral Dissertations

This dissertation consists of two parts. In the first part, I examine Seymour’s Second-Neighborhood Conjecture, which states that every orientation of every simple graph has at least one vertex v such that the number of vertices of out-distance 2 from v is at least as large as the number of vertices of out-distance 1 from it. I present alternative statements of this conjecture using the language of linear algebra, the last one being completely in terms of the inverse of some matrix. In the second part of this dissertation, comprising of Chapters 2 and 3, I examine two conjectures on …

Text-Influenced Expressions Of Understanding: Differences In Kindergartners’ Discourse And Written Retellings Of Traditional And Digital Texts During Buddy Reading, Julie Parrish

LSU Doctoral Dissertations

Buddy reading a text is a collaborative act that typically generates discourse that provides researchers with a glimpse of the comprehending taking place. However, in recent years, the infusion of technology in classrooms has resulted in many traditional texts being replaced by digital versions. Thus, this qualitative case study examined the spoken and written discourse of 12 kindergartners (6 dyads) as they buddy read a traditional and digital text.

Drawing upon two distinct lenses—sociocultural and comprehension signifier—video recordings, transcriptions, and written retellings were analyzed. Specifically, process coding and in vivo coding were used to construct categories and uncover sociocultural patterns …

Benefits Of Continuously Spaced Energies And Scanned Beams For Electron Bolus Conformal Therapy For Left-Side Post-Mastectomy Chest Wall, Stephanie Lianglei Wang

LSU Master's Theses

Purpose: This study assessed the benefits to the heart and lung of using scanned electron beams and continuous energy spacing (ΔR₉₀=0.1 cm) for left-side post-mastectomy radiotherapy (PMRT) patients previously treated with volumetric modulated arc therapy (VMAT). Such beams offer a sharper distal falloff (R_90-10) than do currently available scattered, discrete energy beams, which increases sparing of healthy organs distal to the target.

Methods: Seven left-side PMRT patients previously treated with VMAT at the Mary Bird

Perkins Cancer Center were planned in this study. The patients were divided into two sets; Patient Sets 1 (three patients) and …

The Relationship Between Teacher Beliefs, Adult Attachment, & Teacher Sensitivity, Jeanette Bankston

LSU Master's Theses

Young children spend most of their waking hours in childcare. Therefore, the care and education received in childcare is an important factor in young children's development. Research has revealed that a child’s first three years of life are a period of rapid brain development and teacher education level is associated with increased outcomes for young children. However, the educational requirements to work in childcare remain low. In the absence of formal training and education, early childhood teachers are likely to rely on their beliefs about young children, which can impact the ways teachers care for young children. This research intends …

Hopeless Ugly Food? Estimating Heterogeneous Treatment Effects Of Marketing Strategies On Consumer Attitude And Wtp Via Machine Learning Approaches, Ran Li

LSU Master's Theses

Around one-third of food produced for human consumption is wasted every year, partially caused by consumer's unwillingness to purchase ugly food. We explore opportunities to favorably support consumer's considerations for ugly food by analyzing survey responses from 1099 U.S. adults. We find that without any marketing strategies applied, a great discount has to be provided to sell ugly food. By using appropriate marketing strategies, consumer's attitudes and willingness to pay for ugly food can be changed positively. However, the effects of ugly food marketing attributes are heterogeneous among consumers with different attitudes towards ugly food. Consumers with negative attitudes towards …

The Use Of Refined Analysis In The Evaluation And Determination Of Load Capacity Of Existing Steel Plate Girder Swing Span Bridges, Patrick Duffy

LSU Master's Theses

Steel Plate Girder Swing Span Bridges are a common and traditional movable bridge type typically used in rural areas of Louisiana but can also be found all over the world. As a result of structural analysis code updates that reflect the increase in highway traffic loads and changes in analysis provisions, many of these bridges have become load posted due to deficient ratings using current traditional AASHTO bridge rating methods. This thesis will explore a more accurate load capacity of these bridges using two identical load posted bridges in Louisiana. Refined analysis methods such as finite element (FE) methods are …

Laboratory And Short-Term Field Performance Of Crumb Rubber Modified Asphalt Emulsion In Chip Seal Applications, Md Nafiur Rahman

LSU Master's Theses

Chip sealing is a commonly used pavement maintenance treatment that aims to delay pavement deterioration by reducing water infiltration and restoring skid resistance. Loss of aggregate and bleeding are considered the major failure mechanisms in chip seal, and therefore, are the main design criteria for this treatment method. The objective of this study was to evaluate the laboratory and short-term field performance of chip seals prepared with different types of asphalt emulsions, application rates, and aggregate blends. A newly introduced crumb-rubber modified asphalt emulsion was evaluated that allows chip seal installation at the same temperature of a standard emulsion. Types …

Phosphorus Variability In The Area Of Influence Of The Mid-Barataria Sediment Diversion, Peter Mates

LSU Master's Theses

Man-made levees along the lower Mississippi River prevent delivery of sediment from building and maintaining Louisiana’s coastal wetlands. The Mid-Barataria sediment diversions is designed to reintroduce Mississippi River water, sediment, and nutrients into the sediment-starved Barataria Basin. Phosphorus (P) is an important macronutrient for regulating primary production in coastal marine ecosystems. Wetlands can serve as a sink or source for phosphorus to the overlying water column through various retention and release processes, dependent on concentration. Louisiana coastal systems can be phosphorus limited due to much higher concentrations of bioavailable Nitrogen in river water. The high soluble molar N:P ( >50:1) …

Fish Community Composition And Structure Near A Freshwater River Diversion In Southeastern Louisiana, Rachel L. Snider

LSU Master's Theses

Gulf of Mexico estuaries, particularly in Louisiana, are among the world’s most productive, with landings of commercially- and recreationally-important species exceeding all other contiguous US states. Coastal wetlands are disappearing at an alarming rate because they have been impounded from Mississippi River water and sediment. Although controversial, one proposed solution is to re-route the Mississippi River through diversions and siphons to supply the freshwater and sediments necessary to rebuild vanishing wetlands, particularly in Barataria Bay and Breton Sound, LA. This strategy is one approach outlined in the Louisiana Coastal Master Plan. This project aimed to describe the composition and structure …

Water Quality, Phytoplankton, And Microphytobenthos Dynamics Of Sediment Borrow Areas On The Louisiana Continental Shelf, Monique Boudreaux

LSU Master's Theses

Coastal and continental shelf waters, like northern Gulf of Mexico, are undergoing changes related to natural and human-induced processes causing significant morphological changes. Louisiana, particularly, is experiencing accelerated land loss causing rapid degradation of barrier islands. Restoration of barrier islands employ sediment additions from the continental shelf through dredging. Implications to the ecology of these areas from dredging have been reported in water quality changes, sediment stressors, and contaminant releases, however, research is limited. To understand the implications of dredging on water quality on a seasonal and temporal scale, water samples and sediment cores were taken inside and outside of …

Anatomical Organization And Distinction Of The Sympathetic Inputs To Interscapular Brown Adipose Tissue And Inguinal White Adipose Tissue In The Mouse, Clara Jane Huesing

LSU Doctoral Dissertations

Adipose tissue is a dynamic endocrine organ that contains both the problem and the solution to discovering new therapies for individuals with obesity. Excessive adipose tissue disrupts energy balance and causes a host of comorbidities like insulin resistance and hypertension. On the other hand, adipose tissue is essential for life. During periods of energy demand, sympathetic nerve activity in brown and white adipose tissue stimulates thermogenesis and lipolysis; both of which decrease body weight and improve metabolic health. Therefore, comprehensive insight into the organization of sympathetic innervation and how it communicates with adipocytes is critical in order to utilize its …