Digital Commons Network^™

Xact Implementation Of The Theory Of Cosmological Perturbation In Bianchi I Spacetimes, Ivan Agullo, Javier Olmedo, Vijayakumar Sreenath

Faculty Publications

This paper presents a computational algorithm to derive the theory of linear gauge invariant perturbations on anisotropic cosmological spacetimes of the Bianchi I type. Our code is based on the tensor algebra packages xTensor and xPert, within the computational infrastructure of xAct written in Mathematica. The algorithm is based on a Hamiltonian, or phase space formulation, and it provides an efficient and transparent way of isolating the gauge invariant degrees of freedom in the perturbation fields and to obtain the Hamiltonian generating their dynamics. The restriction to Friedmann-Lemaitre-Robertson-Walker spacetimes is straightforward.

Plumage Patterns: Ecological Functions, Evolutionary Origins, And Advances In Quantification, Nicholas A. Mason, Rauri C.K. Bowie

Faculty Publications

Birds exhibit remarkable variation in plumage patterns, both within individual feathers and among plumage patches. Differences in the size, shape, and location of pigments and structural colors comprise important visual signals involved in mate choice, social signaling, camouflage, and many other functions. While ornithologists have studied plumage patterns for centuries, recent technological advances in digital image acquisition and processing have transformed pattern quantification methods, enabling comprehensive, detailed datasets of pattern phenotypes that were heretofore inaccessible. In this review, we synthesize recent and classic studies of plumage patterns at different evolutionary and organismal scales and discuss the various roles that plumage …

Fine Structure Of Viral Dsdna Encapsidation, Shawn Walker, Javier Arsuaga, Lindsey Hiltner, M. Carme Calderer, Mariel Vázquez

Faculty Publications

Unraveling the mechanisms of packing of DNA inside viral capsids is of fundamental importance to understanding the spread of viruses. It could also help develop new applications to targeted drug delivery devices for a large range of therapies. In this article, we present a robust, predictive mathematical model and its numerical implementation to aid the study and design of bacteriophage viruses for application purposes. Exploiting the analogies between the columnar hexagonal chromonic phases of encapsidated viral DNA and chromonic aggregates formed by plank-shaped molecular compounds, we develop a first-principles effective mechanical model of DNA packing in a viral capsid. The …

Physics Of Nuclei: Key Role Of An Emergent Symmetry, T. Dytrych, K. D. Launey, J. P. Draayer, D. J. Rowe, J. L. Wood, G. Rosensteel, C. Bahri, D. Langr, R. B. Baker

Faculty Publications

We show through first-principles nuclear structure calculations that the special nature of the strong nuclear force determines highly regular patterns heretofore unrecognized in nuclei that can be tied to an emergent approximate symmetry. This symmetry is ubiquitous and mathematically tracks with a symplectic symmetry group. This, in turn, has important implications for understanding the physics of nuclei: we find that nuclei are made of only a few equilibrium shapes, deformed or not, with associated vibrations and rotations. It also opens the path for ab initio large-scale modeling of open-shell intermediate-mass nuclei without the need for renormalized interactions and effective charges.

Examining Interaction Effects In 2d Fermi Gases Using Renormalization Group Theory, Sri Laalitya Uppalapati

LSU Doctoral Dissertations

We use the Renormalization Group (RG) method within the perturbation theory framework to study properties of a balanced, two-dimensional Fermi gas with short-range, attractive interactions in non-superfluid (normal) phase. We find that the RG method allows for the evaluation of logarithmic corrections to Equations of State in various regimes of density and temperature. We present two calculations using RG with perturbation theory. The first being a simplified RG scheme with an interpolation of crossover between RG flow in different regimes. The second calculation features a rigorous derivation whereby the Green's function within a standard perturbation theory is renormalized to derive …

Calibration Transients In Ligo Detectors, Thomas Daniel Abbott

LSU Doctoral Dissertations

This dissertation describes a novel method of analyzing fluctuations in the time-dependent calibration models of the LIGO interferometers to estimate their effect on strain reconstruction for gravitational-wave detections. The time-dependence of the calibration model of each detector is tracked with a set of parameters which are continuously measured while the interferometers are operating. These parameters track slow variations in the sensing function of the detectors as well as the actuators that hold the detectors in an operational state. The time-dependent parameter data during the second observation run (O2 [November 30, 2016 16:00 UTC to August 25, 2017 22:00:00 UTC]) and …

Calorimetry For Low-Energy Electrons Using Charge And Light In Liquid Argon, W. Foreman, R. Acciarri, J. A. Asaadi, W. Badgett, F. D.M. Blaszczyk, R. Bouabid, C. Bromberg, R. Carey, F. Cavanna, J. I. Cevallos Aleman, A. Chatterjee, J. Evans, A. Falcone, W. Flanagan, B. T. Fleming, D. Garcia-Gamez, B. Gelli, T. Ghosh, R. A. Gomes, E. Gramellini, R. Gran, P. Hamilton, C. Hill, J. Ho, J. Hugon, E. Iwai, E. Kearns, E. Kemp, T. Kobilarcik, M. Kordosky, P. Kryczyński, K. Lang, R. Linehan

Faculty Publications

Precise calorimetric reconstruction of 5-50 MeV electrons in liquid argon time projection chambers (LArTPCs) will enable the study of astrophysical neutrinos in DUNE and could enhance the physics reach of oscillation analyses. Liquid argon scintillation light has the potential to improve energy reconstruction for low-energy electrons over charge-based measurements alone. Here we demonstrate light-augmented calorimetry for low-energy electrons in a single-phase LArTPC using a sample of Michel electrons from decays of stopping cosmic muons in the LArIAT experiment at Fermilab. Michel electron energy spectra are reconstructed using both a traditional charge-based approach as well as a more holistic approach that …

Experimental And Computational Tools For Single Cell Analysis In Cancer Diagnostics, Manibarathi Vaithiyanathan

LSU Doctoral Dissertations

Substantial evidence shows that cellular heterogeneity commonly exists within an isogenic or clonal population. Whether in isolation or caused through a combination of the above events, cellular heterogeneity can dramatically influence cellular decision making and cell fate, however, this can be masked by the average response from a population. One approach to solve this issue is to analyze a population at the individual cell level. The goal of this work is to develop high-throughput experimental and computational platforms to screen and quantify single cancer cells for specific intracellular enzyme activities. An interdisciplinary approach was taken to 1) better understand the …

Measurement Of The Muon Neutrino Charged-Current Single Π+ Production On Hydrocarbon Using The T2k Off-Axis Near Detector Nd280, K. Abe, R. Akutsu, A. Ali, C. Alt, J. Amey, C. Andreopoulos, L. Anthony, M. Antonova, S. Aoki, A. Ariga, Y. Ashida, E. T. Atkin, Y. Awataguchi, Y. Azuma, S. Ban, M. Barbi, G. J. Barker, G. Barr, C. Barry, M. Batkiewicz-Kwasniak, A. Beloshapkin, F. Bench, V. Berardi, S. Berkman, R. M. Berner, L. Berns, S. Bhadra, S. Bienstock

Faculty Publications

We report the measurements of the single and double differential cross section of muon neutrino charged-current interactions on carbon with a single positively charged pion in the final state at the T2K off-axis near detector using 5.56×1020 protons on target. The analysis uses data control samples for the background subtraction and the cross section signal, defined as a single negatively charged muon and a single positively charged pion exiting from the target nucleus, is extracted using an unfolding method. The model-dependent cross section, integrated over the T2K off-axis neutrino beam spectrum peaking at 0.6 GeV, is measured to be σ=(11.76±0.44(stat)±2.39(syst))×10-40 …

Field Investigation On Point Bar Dynamics And Planform Evolution In Meandering Rivers, Taylor Rowley

LSU Doctoral Dissertations

Point bars are prominent features in meandering rivers, yet our understanding of the complex interactions among channel morphology, three-dimensional flow structure, and depositional processes associated with modern and active point bars remains incomplete. Thus, the goal of this research is to characterize the morphology, three-dimensional flow structure, and depositional packages associated with point bars along a series of bends with different curvature and channel planform through detailed field measurements and relate to previous literature and current conceptual models.

Chapter 3 investigates the morphology of point bars by comparing estimates of channel curvature to channel and point bar characteristics including width, …

Vibrational And Electronic Structure Of Environmentally Persistent Free Radicals Formed On Metal Oxide Nanoclusters And Single-Crystal Surfaces, Nadra Ibrahim Sakr

LSU Doctoral Dissertations

We have studied the morphology and electronic structure of transition metal oxides (TMOs) nanoparticles and single-crystal surfaces which are known to be active for the formation of environmentally persistent free radicals (EPFRs) from organic precursors. We have also investigated the effect of simulated solar irradiation on the formed EPFRs.

First, we examined the change in the vibrational and structural properties of TiO₂, ZnO, CuO, and Fe₂O₃ nanoparticles due to phenol adsorption at high temperature and thus EPFR formation on the surface of these TMOs. The paramagnetic signal observed by electron paramagnetic resonance (EPR) indicates the …

A Robust Solver For A Second Order Mixed Finite Element Method For The Cahn–Hilliard Equation, Susanne C. Brenner, Amanda E. Diegel, Li Yeng Sung

Faculty Publications

We develop a robust solver for a second order mixed finite element splitting scheme for the Cahn–Hilliard equation. This work is an extension of our previous work in which we developed a robust solver for a first order mixed finite element splitting scheme for the Cahn–Hilliard equation. The key ingredient of the solver is a preconditioned minimal residual algorithm (with a multigrid preconditioner) whose performance is independent of the spatial mesh size and the time step size for a given interfacial width parameter. The dependence on the interfacial width parameter is also mild.

Stellar Nucleosynthesis: Direct Measurement Of The Neutron-Capture Cross Sections Of Stable Germanium Isotopes And Design Of A Next Generation Ion Trap For The Study Of Beta-Delayed Neutron Emission, Alexander Laminack

LSU Doctoral Dissertations

Knowledge of stellar nuclear reaction rates is critical to understanding the cosmic origins of the abundances of elements. In order to determine these reaction rates, accurate measurements of nuclear cross sections are needed. This thesis presents the results of an experiment to directly measure the neutron capture cross sections of 70-Ge, 72-Ge, 74-Ge, and 76-Ge. These measurements were performed at the Los Alamos Neutron Science CEnter (LANSCE) using the Detector for Advanced Neutron Capture Experiments (DANCE). This is the first direct measurement for many of these isotopes across the neutron energy spectrum of 10 eV to 1 MeV using the …

Automatic Shoreline Digitization And Mesh Element Sizing For Hydrodynamic Modeling, Henok Kefelegn

LSU Doctoral Dissertations

The first and most critical step in any coastal hydrodynamics and transport process modeling is identifying land-water boundaries. In a coastal wetland, this has always been a challenge due to the complexity of the wetland and lack of efficient methods, calling for efficient and effective methods to extract and digitize the shorelines. While coastline feature extraction has been increasingly researched, its application in hydrodynamic and environmental modeling, without morphological adjustment, remains limited and suboptimal. Further, there has been a paucity of cost-effective, contextually adaptive and high-quality methods to generate meshes, especially for coastal hydrodynamic modeling. This study has developed and …

Unprepared To Be Culturally Responsive: An Examination Of Secondary Esl Educators In Rural Louisiana, Danielle Marie Butcher

LSU Doctoral Dissertations

The purpose of this study was to examine the problem of instructing English learners in a rural Louisiana district. The following questions guided this study: (1) How do the teachers perceive their pre-service and in-service training for English learners?, (2) How do the teachers perceive their ability to implement culturally responsive pedagogical practices for English learners?, (3) How do the teachers perceive the district’s approach to tangible, informational, and emotional supports for English learners?, and (4) What are the teachers’ perceptions, if any, of sociocultural inequities faced by English learners? And how, if any, do these sociocultural inequities affect the …

Reproductive Biology And Trophic Niche Of Hardhead Catfish In The Northern Gulf Of Mexico, Lucas G. Pensinger

LSU Master's Theses

Generally, marine fishes have very high fecundity with each female producing many small eggs which hatch into small larvae. However, Ariopsis felis, a species of marine catfish common to coastal Louisiana, has low fecundity and produces the largest eggs of the teleost fishes. Despite wide range and generally high abundance, we know very little of A. felis biology and population. The few existing studies of A. felis are older and often have questionable or unclear methodology.

I examined four aspects of A. felis reproductive biology: 1) reproductive timing,

2) fecundity, 3) length at first maturity, and 4) mouth brooding. …

Development And Validation Of A Simplified Transient Two-Phase Flow Model For Any Pipe Inclination, Ligia Tornisiello

LSU Master's Theses

This study describes the development and validation of an improved simplified model for transient two-phase flow for any pipe inclination. The simplified model proposed has been validated with field-scale test well and laboratorial data, and also compared to the state-of-the-art commercial simulator for transient two-phase flow in pipes. The results of the simplified model showed an agreement within the range of ±30% for the holdup predictions for 65% of the scenarios, and an agreement within the range of ±30% for the pressure predictions for 82% of the scenarios considered in this work.

In the oil and gas industry, transient two-phase …

Liability Of The Structural Engineer: Establishing, Quantifying, And Managing Risks, Justin Thomas Ittmann

LSU Doctoral Dissertations

Liability is an important topic to all practicing professionals—including practicing engineers. However, the topic of liability does not receive the necessary attention required relative to other professions. Further, engineers that desire to learn more about liability in relation to their practice do not have many university options within an engineering curriculum or from outside materials available to a non-legally trained engineer. The goal of the study is to provide a comprehensive overview of liability directed towards an intelligent practicing engineer, while avoiding unnecessary over-simplification of the material. This study initially provides an in depth survey of the legal standard of …

Geometry And Topology Of Estuary And Braided River Channel Networks Automatically Extracted From Topographic Data, Matthew Hiatt

Faculty Publications

No abstract provided.

Modeling The Effects Of Trait-Mediated Dispersal On Coexistence Of Mutualists, James T. Cronin, Jerome Goddard, Amila Muthunayake, Ratnasingham Shivaji

Faculty Publications

© 2020 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) Even though mutualistic interactions are ubiquitous in nature, we are still far from making good predictions about the fate of mutualistic communities under threats such as habitat fragmentation and climate change. Fragmentation often causes declines in abundance of a species due to increased susceptibility to edge effects between remnant habitat patches and lower quality “matrix” surrounding these focal patches. It has been argued that ecological communities are replete with trait-mediated indirect effects, and that these effects …

Modeling The Effects Of Density Dependent Emigration, Weak Allee Effects, And Matrix Hostility On Patch-Level Population Persistence, James T. Cronin, Nalin Fonseka, Jerome Goddard, Jackson Leonard, Ratnasingham Shivaji

Faculty Publications

© 2020 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) The relationship between conspecific density and the probability of emigrating from a patch can play an essential role in determining the population-dynamic consequences of an Allee effect. In this paper, we model a population that inside a patch is diffusing and growing according to a weak Allee effect per-capita growth rate, but the emigration probability is dependent on conspecific density. The habitat patch is one-dimensional and is surrounded by a tuneable hostile matrix. We consider five …

An Efficient And Computationally Robust Statistical Method For Analyzing Case-Control Mother–Offspring Pair Genetic Association Studies, Hong Zhang, Bhramar Mukherjee, Victoria Arthur, Gang Hu, Hagit Hochner, Jinbo Chen

Population and Public Health Science Faculty Publications

Case-control mother–offspring pair design has been widely adopted for studying early-life and women’s pregnancy health. It allows assessment of pre-and perinatal environmental risk factors as well as both maternal and offspring genetic risk factors. Data arising from this design is routinely analyzed using standard prospective logistic regression. Such data has two unique fea-tures: the offspring genotypes are not correlated with maternal environmental risk factors given maternal genotypes, and offspring and maternal genotypes are related through mendelian transmission. In this work, built upon a novel regression model relating maternal genotypes to environmental risk factors, we proposed a novel retrospective likelihood method …

The Lonely Only: An Analysis Of The Theorizing Of United States Quota Culture Competiveness On The Modern-Day Black Woman, Russell Chamblee Wilder

Honors Capstones

No abstract provided.

Rotation And Spin And Position Operators In Relativistic Gravity And Quantum Electrodynamics, Robert F. O’Connell

Faculty Publications

First, we examine how spin is treated in special relativity and the necessity of introducing spin supplementary conditions (SSC) and how they are related to the choice of a center-of-mass of a spinning particle. Next, we discuss quantum electrodynamics and the Foldy–Wouthuysen transformation which we note is a position operator identical to the Pryce–Newton–Wigner position operator. The classical version of the operators are shown to be essential for the treatment of classical relativistic particles in general relativity, of special interest being the case of binary systems (black holes/neutron stars) which emit gravitational radiation.

Effect Of Mitigation Measures On The Spreading Of Covid-19 In Hard-Hit States In The Us, K M. Tam, N Walker, J Moreno

Faculty Publications

State government-mandated social distancing measures have helped to slow the growth of the COVID-19 pandemic in the United States. Many of the current predictive models of the development of COVID-19, especially after mitigation efforts, partially rely on extrapolations from data collected in other countries. Since most states enacted stay-at-home orders towards the end of March, the resulting effects of social distancing should be reflected in the death and infection counts by the end of April. Using the data available through April 25(th), we investigate the change in the infection rate due to the mitigation efforts and project death and infection …

First Person: The Pandemic's Silver Lining: Real Talk For Future Teachers, J Hipp

Faculty Publications

When the COVID-19 pandemic closed her university campus, Jamie Hipp had to move her popular arts integration class for preservice teachers to a virtual format. She was surprised to learn that her students wanted more than regular sessions during their scheduled class times; they wanted additional opportunities for real teacher talk about going on interviews, setting up a classroom, and other practical matters that weren't being covered in their preservice program. Hipp set up a series of virtual sessions on topics of interest to students, in addition to regular class sessions. The sessions went so well that Hipp intends to …

Review Of Particle Physics, P. A. Zyla, R. M. Barnett, J. Beringer, O. Dahl, D. A. Dwyer, D. E. Groom, C. J. Lin, K. S. Lugovsky, E. Pianori, D. J. Robinson, C. G. Wohl, W. M. Yao, K. Agashe, G. Aielli, B. C. Allanach, C. Amsler, M. Antonelli, E. C. Aschenauer, D. M. Asner, H. Baer, Sw Banerjee, L. Baudis, C. W. Bauer, J. J. Beatty, V. I. Belousov, S. Bethke, A. Bettini, O. Biebel, K. M. Black, E. Blucher, O. Buchmuller, V. Burkert, M. A. Bychkov

Faculty Publications

The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,324 new measurements from 878 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. …

Lsu General Catalog 2020-2021, Louisiana State University And Agricultural And Mechanical College

LSU General Catalog

The LSU General Catalog describes all undergraduate and graduate departments and programs with degree requirements and courses offered for each one. The LSU General Catalog includes information on registration and financial aid as well as academic services offered to all students.

Evaluation Of Gene Flow In Structured And Seed Blend Refuge Systems Of Non-Bt And Bt Corn, Galen P. Dively, Fangneng Huang, Isaac Oyediran, Tony Burd, Shannon Morsello

Faculty Publications

Gene flow between Bt and non-Bt plants can have implications for resistance management. In 2013 and 2014, field trials in Maryland and Louisiana measured gene flow in three refuge systems: (1) structured refuge stand of purple-seeded corn flanked on both sides by stands of yellow corn; (2) seed blend of yellow corn containing purple corn as refuges; and (3) seed blend of purple-seeded corn containing yellow corn as refuges. The presence of cross-pollinated purple kernels was used as a marker to quantify gene flow. In the structured refuge, cross-pollination between Bt and structured refuge plants averaged 5.4% on adjacent rows …

Early Detection Of Parkinson's Disease Using Deep Learning And Machine Learning, Wu Wang, Junho Lee, Fouzi Harrou, Ying Sun

Faculty Publications

Accurately detecting Parkinson's disease (PD) at an early stage is certainly indispensable for slowing down its progress and providing patients the possibility of accessing to disease-modifying therapy. Towards this end, the premotor stage in PD should be carefully monitored. An innovative deep-learning technique is introduced to early uncover whether an individual is affected with PD or not based on premotor features. Specifically, to uncover PD at an early stage, several indicators have been considered in this study, including Rapid Eye Movement and olfactory loss, Cerebrospinal fluid data, and dopaminergic imaging markers. A comparison between the proposed deep learning model and …