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Articles 181 - 210 of 3417

Full-Text Articles in Physical Sciences and Mathematics

Bat Habitat Use And Activity In Forests Of Central Louisiana, Jane M. Kunberger Apr 2022

Bat Habitat Use And Activity In Forests Of Central Louisiana, Jane M. Kunberger

LSU Master's Theses

In the southeastern U.S., where forests are the primary land cover type and trees are often harvested for production purposes, understanding how forestry practices influence bat distributions is critical for bat conservation and management. It is also important for researchers to quantify and report variation in the performance of automated recordings units (ARUs) used to survey for bats because several key features of ARUs (e.g., microphone sensitivity, triggering thresholds) can influence an ARUs ability to detect bat calls. My goals were (1) to examine the influence of forest management practices on seasonal bat species occurrence and activity in central Louisiana, …


Competitive Sorption And Transport Of Heavy Metals In Soil And Mn Oxide-Coated Sand, Joshua Tyler Padilla Apr 2022

Competitive Sorption And Transport Of Heavy Metals In Soil And Mn Oxide-Coated Sand, Joshua Tyler Padilla

LSU Doctoral Dissertations

This study investigated the competitive sorption of Ni, Pb, and Zn as well as synergistic interactions between Ni and phosphate (P) in soils and Mn oxide-coated sand. During stirred-flow experiments, the sorption of heavy metal cations by Olivier soil was mutually reduced when applied simultaneously. When applied consecutively, the cation of higher affinity was able to displace the cation of lower affinity from the soil surface, however, no evidence for the reverse case was observed. A novel general exchange kinetics model was able to correctly describe such displacement. Competition between Ni and Zn mutually increased mobility in Olivier and Windsor …


New Aspects Of Optical Coherence And Their Potential For Quantum Technologies, Nathaniel Robert Miller Apr 2022

New Aspects Of Optical Coherence And Their Potential For Quantum Technologies, Nathaniel Robert Miller

LSU Doctoral Dissertations

Currently, optical technology impacts most of our lives, from light used in scientific measurement to the fiber optic cables that makeup the backbone of the internet. However, as our current optical infrastructure grows, we discover that these technologies are not limitless. Astronomers find themselves unable resolve stars that are too close to one another. Meanwhile, the internet is always under threat as our computer technology improves and more complex ways to break encryption emerge, threatening our personal information and infrastructure. However, our current optical technology functions on classical principles, and can be easily improved by incorporating our knowledge of quantum …


A Numerical Investigation Of Flood And Sediment Dynamics Over The Coastal Watersheds During Hurricane Events, Dongxiao Yin Apr 2022

A Numerical Investigation Of Flood And Sediment Dynamics Over The Coastal Watersheds During Hurricane Events, Dongxiao Yin

LSU Doctoral Dissertations

Landfalling tropical cyclones can cause catastrophic floods and sediment disturbance over the coastal watersheds. This study aims to unravel the contribution of different processes to hurricane-induced flooding, to assess the uncertainties in flood modelling and forecasting, and to advance the techniques in sediment simulation over coastal watersheds during hurricanes.

First, I examined the hydrometeorology and hydrology of Hurricane Florence (2018) induced inland flooding. My results suggest that the slow motion in combination with the “L-shaped” path was the most distinctive feature of the hurricane that incurred catastrophic and widespread rainfall and flooding over the Cape Fear River Basin (CFRB).

Second, …


Unavoidable Structures In Large And Infinite Graphs, Sarah Allred Apr 2022

Unavoidable Structures In Large And Infinite Graphs, Sarah Allred

LSU Doctoral Dissertations

In this work, we present results on the unavoidable structures in large connected and large 2-connected graphs. For the relation of induced subgraphs, Ramsey proved that for every positive integer r, every sufficiently large graph contains as an induced subgraph either Kr or Kr. It is well known that, for every positive integer r, every sufficiently large connected graph contains an induced subgraph isomorphic to one of Kr, K1,r, and Pr. We prove an analogous result for 2-connected graphs. Similarly, for infinite graphs, every infinite connected graph contains an induced subgraph …


Effects Of Meteorologic Events On Wave Climate And Current Regime In A Shallow, Microtidal Bay, Jay S. Merrill Apr 2022

Effects Of Meteorologic Events On Wave Climate And Current Regime In A Shallow, Microtidal Bay, Jay S. Merrill

LSU Master's Theses

Along coastal Louisiana and within the shallow microtidal Barataria Bay estuary, meteorological events can play a primary role in influencing wave climate and circulation patterns. Understanding the effects of hurricanes and smaller tropical storms on hydrodynamic processes is important for constraining and predicting hydrodynamic variation in Barataria Bay, which, largely due to impacts from wave energy, is currently experiencing rapid wetland loss and is a major focus of coastal restoration efforts. Two bottom-mounted upward-facing Acoustic Current Doppler Profilers and wave, temperature, and depth recorders were installed in the lower portions of Barataria Bay to measure the wave climate and three-dimensional …


Observing Reactive Events At The Aqueous Graphene Oxide Interface Using Deep Neural Network Potentials, Lukas Kim Apr 2022

Observing Reactive Events At The Aqueous Graphene Oxide Interface Using Deep Neural Network Potentials, Lukas Kim

Honors Theses

No abstract provided.


Observing And Exploring Intrinsic Characteristics Of Type Ia Supernova, Connor Langevin Apr 2022

Observing And Exploring Intrinsic Characteristics Of Type Ia Supernova, Connor Langevin

Honors Theses

No abstract provided.


Mathematica Assessment Of Spatial Reasoning Development After Virtual Reality Collaboration, Arthur Odenheimer Apr 2022

Mathematica Assessment Of Spatial Reasoning Development After Virtual Reality Collaboration, Arthur Odenheimer

Honors Theses

No abstract provided.


Gl(1|1) Graph Connections, Andrea Bourque Apr 2022

Gl(1|1) Graph Connections, Andrea Bourque

Honors Theses

No abstract provided.


Opers On The Projective Line, Wronskian Relations, And The Bethe Ansatz, Ty J. Brinson Apr 2022

Opers On The Projective Line, Wronskian Relations, And The Bethe Ansatz, Ty J. Brinson

Honors Theses

No abstract provided.


Trophic Relationships Between Tadpoles And Other Aquatic Organisms In Sub-Tropical Ponds, Kira Cates Apr 2022

Trophic Relationships Between Tadpoles And Other Aquatic Organisms In Sub-Tropical Ponds, Kira Cates

Honors Theses

No abstract provided.


Generative Adversarial Networks Take On Hand Drawn Sketches: An Application To Louisiana Culture And Mardi Gras Fashion, Stephanie Hines Apr 2022

Generative Adversarial Networks Take On Hand Drawn Sketches: An Application To Louisiana Culture And Mardi Gras Fashion, Stephanie Hines

Honors Theses

No abstract provided.


Collisions On Campus: Species-Specific Susceptibility Of Resident And Migrant Birds To Window Strikes At Louisiana State University, Jordan A. Mouton Apr 2022

Collisions On Campus: Species-Specific Susceptibility Of Resident And Migrant Birds To Window Strikes At Louisiana State University, Jordan A. Mouton

Honors Theses

No abstract provided.


Expression And Purification Of Tag-Free Chlamydia Trachomatis Scc4 For Improved Nmr Structural Studies, Peter Howard Apr 2022

Expression And Purification Of Tag-Free Chlamydia Trachomatis Scc4 For Improved Nmr Structural Studies, Peter Howard

Honors Theses

No abstract provided.


The Effect Of Channel Stability On Fish Condition And Diet In Thompson Creek, La, Alexia Lagrone Apr 2022

The Effect Of Channel Stability On Fish Condition And Diet In Thompson Creek, La, Alexia Lagrone

Honors Theses

No abstract provided.


Are Long-Period Exoplants Around Cool Stars More Common Than We Thought?, Emily Jane Safron Mar 2022

Are Long-Period Exoplants Around Cool Stars More Common Than We Thought?, Emily Jane Safron

LSU Doctoral Dissertations

The Kepler mission has been the catalyst for discovery of nearly 5,000 confirmed and candidate exoplanets. The majority of these candidates orbit Sun-like stars, and have orbital periods comparable to or shorter than that of the Earth, due to the selection bias inherent in the transit method and the limitations of automated transit search algorithms. We aim to develop a richer understanding of the population of exoplanets around the lowest-mass stars, the M spectral type. We are particularly interested in exoplanets with long orbital periods, which are difficult or impossible to find using standard transit search algorithms. In our study, …


Performance Analysis And Improvement For Scalable And Distributed Applications Based On Asynchronous Many-Task Systems, Nanmiao Wu Mar 2022

Performance Analysis And Improvement For Scalable And Distributed Applications Based On Asynchronous Many-Task Systems, Nanmiao Wu

LSU Doctoral Dissertations

As the complexity of recent and future large-scale data and exascale systems architectures grows, so do productivity, portability, software scalability, and efficient utilization of system resources challenges presented to both industry and the research community. Software solutions and applications are expected to scale in performance on such complex systems. Asynchronous many-task (AMT) systems, taking advantage of multi-core architectures with light-weight threads, asynchronous executions, and smart scheduling, are showing promise in addressing these challenges.

In this research, we implement several scalable and distributed applications based on HPX, an exemplar AMT runtime system. First, a distributed HPX implementation for a parameterized benchmark …


Synthesis Of Thiol-Acrylate Hydrogels For 3d Cell Culture And Microfluidic Applications, Anowar Hossain Khan Mar 2022

Synthesis Of Thiol-Acrylate Hydrogels For 3d Cell Culture And Microfluidic Applications, Anowar Hossain Khan

LSU Doctoral Dissertations

Globally cell culture is an $18.98 billion industry as of 2020, with an 11.6 percent annual growth rate. Drug discovery has an estimated worth of $69.8 billion in 2020 and is predicted to grow to $110.4 billion by 2025. Three-dimensional (3D) cell culture of cancer cells is one of the rapidly growing felids since it better recapitulates in vivo conditions compared to two-dimensional (2D) models. However, it is challenging to grow 3D tumor spheroids outside the body, and some of the existing technology can generate these spheroids outside the human body but poorly mimic in vivo tumor models. Therefore, there …


The Spectra Of Hydrogen-Deficient Carbon Stars: The Effects Of Evolution And Nucleosynthesis, Courtney Lauren Crawford Mar 2022

The Spectra Of Hydrogen-Deficient Carbon Stars: The Effects Of Evolution And Nucleosynthesis, Courtney Lauren Crawford

LSU Doctoral Dissertations

The rare class of stars known as the Hydrogen-deficient Carbon (HdC) stars includes the R Coronae Borealis (RCB) variables and the non-variable Dustless HdC (dLHdC) stars. These stars are believed to be formed via the merger of two white dwarf (WD) stars. They are known to exhibit many spectral peculiarities, such as partial helium burning products, enhancement of s-processed material and severe hydrogen-deficiency. In this work I explore many facets of HdC evolution. I begin by creating 18 HdC models in the stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA) by merging two WD progenitors and evolving the …


Computational Study Of The Reactions Of Heteroatomic Compounds On Ceo2, Suman Bhasker Ranganath Mar 2022

Computational Study Of The Reactions Of Heteroatomic Compounds On Ceo2, Suman Bhasker Ranganath

LSU Doctoral Dissertations

The mechanisms of ambient-temperature reactions of heteroatomic compounds catalyzed by ceria (CeO2), an archetypical reducible oxide, for enzyme mimetics, environmental protection, and chemical synthesis are investigated in this dissertation using theoretical methods. CeO2 is modeled with thermodynamically stable low-index surfaces exposed by commonly studied ceria thin films and nano particles. To understand phosphatase-like dephosphorylation activity, stable adsorption states and surface reactions of model phosphates are examined. Binding of the central P-atom to surface lattice oxygen (Olatt) supplemented by phosphoryl O-Ce interaction is the only stable adsorption state for the un-dissociated molecule. Deprotonation of phosphate monoesters, …


Kinetics, Characterization, And Applications In The Development Of Next-Generation Cure-On-Demand Polymeric Materials Through Frontal Polymerization, Daniel Paul Gary Mar 2022

Kinetics, Characterization, And Applications In The Development Of Next-Generation Cure-On-Demand Polymeric Materials Through Frontal Polymerization, Daniel Paul Gary

LSU Doctoral Dissertations

Frontal polymerization (FP) is a process in which a front propagates in a localized reaction zone converting monomer into polymer. This work explored the kinetics and applications of FP for the development of cure-on-demand materials.

The kinetic effects of fillers on frontal polymerization have not been thoroughly explored. In Chapter 2, various fillers were used, and their effects on front velocity and front temperature were determined. Clay minerals are primarily used, but the thermal conductive effects of milled carbon fiber were also explored. It was found that some fillers inhibit frontal polymerization through radical scavenging, while others increased the front …


Spectral Theorem Approach To The Characteristic Function Of Quantum Observables, Andreas Boukas Mar 2022

Spectral Theorem Approach To The Characteristic Function Of Quantum Observables, Andreas Boukas

Journal of Stochastic Analysis

No abstract provided.


Digital Discrimination In The Sharing Economy: Evidence, Policy, And Feature Analysis, Miroslav Tushev Mar 2022

Digital Discrimination In The Sharing Economy: Evidence, Policy, And Feature Analysis, Miroslav Tushev

LSU Doctoral Dissertations

Applications (apps) of the Digital Sharing Economy (DSE), such as Uber, Airbnb, and TaskRabbit, have become a main facilitator of economic growth and shared prosperity in modern-day societies. However, recent research has revealed that the participation of minority groups in DSE activities is often hindered by different forms of bias and discrimination. Evidence of such behavior has been documented across almost all domains of DSE, including ridesharing, lodging, and freelancing. However, little is known about the under- lying design decisions of DSE systems which allow certain demographics of the market to gain unfair advantage over others. To bridge this knowledge …


Construction Of The Canonical Representation From A Noncanonical Representation, Yuji Hibino Mar 2022

Construction Of The Canonical Representation From A Noncanonical Representation, Yuji Hibino

Journal of Stochastic Analysis

No abstract provided.


A Multiparameter Degeneracy In Microlensing Events With Extreme Finite Source Effects, Samson A. Johnson, Matthew T. Penny, B. Scott Gaudi Mar 2022

A Multiparameter Degeneracy In Microlensing Events With Extreme Finite Source Effects, Samson A. Johnson, Matthew T. Penny, B. Scott Gaudi

Faculty Publications

For microlenses with sufficiently low mass, the angular radius of the source star can be much larger than the angular Einstein ring radius of the lens. For such extreme finite source effect (EFSE) events, finite source effects dominate throughout the duration of the event. Here, we demonstrate and explore a continuous degeneracy between multiple parameters of such EFSE events. The first component in the degeneracy arises from the fact that the directly observable peak change of the flux depends on both the ratio of the angular source radius to the angular Einstein ring radius and the fraction of the baseline …


Gaia Gral: Gaia Dr2 Gravitational Lens Systems. Vii. Xmm-Newton Observations Of Lensed Quasars, Thomas Connor, Daniel Stern, Alberto Krone-Martins, S. G. Djorgovski, Matthew J. Graham Mar 2022

Gaia Gral: Gaia Dr2 Gravitational Lens Systems. Vii. Xmm-Newton Observations Of Lensed Quasars, Thomas Connor, Daniel Stern, Alberto Krone-Martins, S. G. Djorgovski, Matthew J. Graham

Faculty Publications

We present XMM-Newton X-ray observations of nine confirmed lensed quasars at 1 less than or similar to z less than or similar to 3 identified by the Gaia Gravitational Lens program. Eight systems are strongly detected, with 0.3-8.0 keV fluxes F (0.3-8.0) greater than or similar to 5 x10(-14) erg cm(-2) s(-1). Modeling the X-ray spectra with an absorbed power law, we derive power-law photon indices and 2-10 keV luminosities for the eight detected quasars. In addition to presenting sample properties for larger quasar population studies and for use in planning for future caustic-crossing events, we also identify three quasars …


90snet:, Seth Richard Mar 2022

90snet:, Seth Richard

Honors Theses

No abstract provided.


Peak Chlorophyll A Concentrations In The Lower Mississippi River From 1997 To 2018, R. Eugene Turner, Charles S. Milan, Erick M. Swenson, James M. Lee Mar 2022

Peak Chlorophyll A Concentrations In The Lower Mississippi River From 1997 To 2018, R. Eugene Turner, Charles S. Milan, Erick M. Swenson, James M. Lee

Faculty Publications

Large and turbid rivers have varying temperatures, light conditions, nutrient availability, and nutrient ratios that may affect phytoplankton communities and occur within a changing world of point and nonpoint source nutrient loadings. We investigated how these physical and chemical factors affect Chlorophyll a (Chl a) concentrations in the Mississippi River, the largest river in North America, by sampling 878 times from February 1997 to December 2018 near its terminus at Baton Rouge, Louisiana. We hypothesized that nutrient concentrations and ratios were significant factors limiting phytoplankton biomass accumulations in this turbid river. The Chl a concentrations were in the "poor" water …


New Limit Theorems For Increments Of Birth-And-Death Processes With Linear Rates, Alexander Ya. Kreinin, Vladimir V. Vinogradov Feb 2022

New Limit Theorems For Increments Of Birth-And-Death Processes With Linear Rates, Alexander Ya. Kreinin, Vladimir V. Vinogradov

Journal of Stochastic Analysis

No abstract provided.