Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Louisiana State University

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 391 - 420 of 3417

Full-Text Articles in Physical Sciences and Mathematics

Planet Hunters Tess Ii: Findings From The First Two Years Of Tess, N. L. Eisner, O. Barragan, C. Lintott, S. Aigrain, B. Nicholson, T. S. Boyajian, S. Howell, C. Johnston, B. Lakeland, G. Miller, A. Mcmaster, H. Parviainen, E. J. Safron, M. E. Schwamb, L. Trouille, S. Vaughan, N. Zicher, C. Allen, S. Allen, M. Bouslog, C. Johnson, M. N. Simon, Z. Wolfenbarger, E. M. L. Baeten, D. M. Bundy, T. Hoffman Mar 2021

Planet Hunters Tess Ii: Findings From The First Two Years Of Tess, N. L. Eisner, O. Barragan, C. Lintott, S. Aigrain, B. Nicholson, T. S. Boyajian, S. Howell, C. Johnston, B. Lakeland, G. Miller, A. Mcmaster, H. Parviainen, E. J. Safron, M. E. Schwamb, L. Trouille, S. Vaughan, N. Zicher, C. Allen, S. Allen, M. Bouslog, C. Johnson, M. N. Simon, Z. Wolfenbarger, E. M. L. Baeten, D. M. Bundy, T. Hoffman

Faculty Publications

We present the results from the first two years of the Planet Hunters TESS (PHT) citizen science project, which identifies planet candidates in the TESS (Transiting Exoplanet Survey Satellite) data by engaging members of the general public. Over 22000 citizen scientists from around the world visually inspected the first 26 sectors of TESS data in order to help identify transit-like signals. We use a clustering algorithm to combine these classifications into a ranked list of events for each sector, the top 500 of which are then visually vetted by the science team. We assess the detection efficiency of this methodology …


Dynamical Modelling Of Cxogbs J175553.2-281633: A 10 H Long Orbital Period Cataclysmic Variable, Sebastian Gomez, Manuel A. P. Torres, Peter G. Jonker, Zuzanna Kostrzewa-Rutkowska, Theo F. J. Van Grunsven, Andrzej Udalski, Robert I. Hynes, Craig O. Heinke, Thomas J. Maccarone, Ricardo Salinas, Jay Strader Mar 2021

Dynamical Modelling Of Cxogbs J175553.2-281633: A 10 H Long Orbital Period Cataclysmic Variable, Sebastian Gomez, Manuel A. P. Torres, Peter G. Jonker, Zuzanna Kostrzewa-Rutkowska, Theo F. J. Van Grunsven, Andrzej Udalski, Robert I. Hynes, Craig O. Heinke, Thomas J. Maccarone, Ricardo Salinas, Jay Strader

Faculty Publications

We present modelling of the long-term optical light and radial velocity curves of the binary stellar system CXOGBS J175553.2-281633, first detected in X-rays in the Chandra Galactic Bulge Survey. We analysed 7 yr of optical I-band photometry from Optical Gravitational Lensing Experiment and found long-term variations from year to year. These long-term variations can most likely be explained with by either variations in the luminosity of the accretion disc or a spotted secondary star. The phased light curve has a sinusoidal shape, which we interpret as being due to ellipsoidal modulations. We improve the orbital period to be P = …


Quasinormal Modes And Their Overtones At The Common Horizon In A Binary Black Hole Merger, Pierre Mourier, Xisco Jimenez Forteza, Daniel Pook-Kolb, Dadri Krishnan, Erik Schnetter Feb 2021

Quasinormal Modes And Their Overtones At The Common Horizon In A Binary Black Hole Merger, Pierre Mourier, Xisco Jimenez Forteza, Daniel Pook-Kolb, Dadri Krishnan, Erik Schnetter

Faculty Publications

It is expected that all astrophysical black holes in equilibrium are well described by the Kerr solution. Moreover, any black hole far away from equilibrium, such as one initially formed in a compact binary merger or by the collapse of a massive star, will eventually reach a final equilibrium Kerr state. At sufficiently late times in this process of reaching equilibrium, we expect that the black hole is modeled as a perturbation around the final state. The emitted gravitational waves will then be damped sinusoids with frequencies and damping times given by the quasinormal mode spectrum of the final Kerr …


Characterization, Immobilization, And Polymer Related Applications Of Watermelon Seed Powder, A Practical Source Of Urease Enzyme, Anthony Quan Quoc Mai Feb 2021

Characterization, Immobilization, And Polymer Related Applications Of Watermelon Seed Powder, A Practical Source Of Urease Enzyme, Anthony Quan Quoc Mai

LSU Doctoral Dissertations

Urease enzyme was crystallized almost a century ago, and to this day its intrinsic stability is not ideal for everyday applications. This work introduces a new process by which a naturally encapsulated material, watermelon seed powder (WMSP), is characterized for its stability and activity. WMSP enzymatic activity has been measured for over a year at various storage conditions—exposed to ambient atmosphere for a year, WMSP retained above 90% activity. In aqueous conditions, the enzyme maintained above 60% activity after two months; with the addition of a preservative that number stays at about 90%. There is a pH shift of the …


Application Of Compound-Specific Stable Isotopes And Molecular Biomarkers To Paleoclimatic And Paleoecological Reconstructions, Mingqiu Hou Feb 2021

Application Of Compound-Specific Stable Isotopes And Molecular Biomarkers To Paleoclimatic And Paleoecological Reconstructions, Mingqiu Hou

LSU Doctoral Dissertations

Compound-specific stable isotope analysis and biomarker-based paleothermometry have been increasingly applied to for paleoclimate and paleoecology studies. The first project aims to reconstruct the paleoclimate in the Qaidam Basin during the last glacial period. Qaidam Basin in the Northern Tibetan Plateau is a critical eolian factory located at a unique geographic location that links the Westerlies and the Asian summer monsoons. However, how the interactions of two climatic systems influence the paleohydrology that in turn impacts the eolian production in the Qaidam Basin has been seldom explored. Our compound-specific hydrogen isotope and UK 37 temperature data found that the …


Investigation Of The Structure And Dynamics Of Novel Battery Electrolytes By Utilizing Multidimensional Infrared Spectroscopic Techniques, Susith Rajitha Abeythunga Galle Kankanamge Feb 2021

Investigation Of The Structure And Dynamics Of Novel Battery Electrolytes By Utilizing Multidimensional Infrared Spectroscopic Techniques, Susith Rajitha Abeythunga Galle Kankanamge

LSU Doctoral Dissertations

Novel battery technologies are being developed due to the high global demand for energy in many fields where different specifications are required. The battery electrolyte provides a medium for ions to diffuse between electrodes and its composition determines the compatibility with the electrode pair. While many works focus on characterizing novel electrolyte systems to advance new batteries, the understanding of the microscopic structure and dynamics of speciations present in these electrolytes is limited. Many experiment methods have obtained incomplete time-averaged structure information due to lack of instrumental time resolution compared to the molecular intrinsic time sales of electrolytes that range …


First Exit-Time Analysis For An Approximate Barndorff-Nielsen And Shephard Model With Stationary Self-Decomposable Variance Process, Shantanu Awasthi, Indranil Sengupta Feb 2021

First Exit-Time Analysis For An Approximate Barndorff-Nielsen And Shephard Model With Stationary Self-Decomposable Variance Process, Shantanu Awasthi, Indranil Sengupta

Journal of Stochastic Analysis

No abstract provided.


Quantum Theories Associated To Increasing Hilbert Space Filtrations And Generalized Jacobi 3–Diagonal Relation, Luigi Accardi, Yun Gang Lu Feb 2021

Quantum Theories Associated To Increasing Hilbert Space Filtrations And Generalized Jacobi 3–Diagonal Relation, Luigi Accardi, Yun Gang Lu

Journal of Stochastic Analysis

No abstract provided.


Rate Of Convergence In The Central Limit Theorem For Iid Pareto Variables, Claas Becker, Manuel Bohnet, Sarah Kummert Feb 2021

Rate Of Convergence In The Central Limit Theorem For Iid Pareto Variables, Claas Becker, Manuel Bohnet, Sarah Kummert

Journal of Stochastic Analysis

No abstract provided.


Noncentral Limit Theorem For Large Wishart Matrices With Hermite Entries, Charles-Philippe Diez, Ciprian A. Tudor Feb 2021

Noncentral Limit Theorem For Large Wishart Matrices With Hermite Entries, Charles-Philippe Diez, Ciprian A. Tudor

Journal of Stochastic Analysis

No abstract provided.


Fuzzy P-Value Of Hypotheses Tests With Crisp Data Using Non-Asymptotic Fuzzy Estimators, Nikos Mylonas, Basil K. Papadopoulos Feb 2021

Fuzzy P-Value Of Hypotheses Tests With Crisp Data Using Non-Asymptotic Fuzzy Estimators, Nikos Mylonas, Basil K. Papadopoulos

Journal of Stochastic Analysis

No abstract provided.


Identification Of A Local Sample Of Gamma-Ray Bursts Consistent With A Magnetar Giant Flare Origin, E. Burns, D. Svinkin, K Hurley, Z. Wadiasingh, M. Negro, G. Younes, R. Hamburg, A. Ridnaia, D. Cook, S. B. Cenko, R. Aloisi, G. Ashton, M. Baring, M. S. Briggs, N. Christensen, D. Frederiks, A. Goldstein, C. M. Hui, D. L. Kaplan, M. M. Kasliwal, D. Kocevski, O. J. Roberts, V. Savchenko, A. Tohuvavohu, P. Veres, C. A. Wilson-Hodge Feb 2021

Identification Of A Local Sample Of Gamma-Ray Bursts Consistent With A Magnetar Giant Flare Origin, E. Burns, D. Svinkin, K Hurley, Z. Wadiasingh, M. Negro, G. Younes, R. Hamburg, A. Ridnaia, D. Cook, S. B. Cenko, R. Aloisi, G. Ashton, M. Baring, M. S. Briggs, N. Christensen, D. Frederiks, A. Goldstein, C. M. Hui, D. L. Kaplan, M. M. Kasliwal, D. Kocevski, O. J. Roberts, V. Savchenko, A. Tohuvavohu, P. Veres, C. A. Wilson-Hodge

Faculty Publications

Cosmological gamma-ray bursts (GRBs) are known to arise from distinct progenitor channels: short GRBs mostly from neutron star mergers and long GRBs from a rare type of core-collapse supernova (CCSN) called collapsars. Highly magnetized neutron stars called magnetars also generate energetic, short-duration gamma-ray transients called magnetar giant flares (MGFs). Three have been observed from the Milky Way and its satellite galaxies, and they have long been suspected to constitute a third class of extragalactic GRBs. We report the unambiguous identification of a distinct population of four local (<5 Mpc) short GRBs, adding GRB 070222 to previously discussed events. While identified solely based on alignment with nearby star-forming galaxies, their rise time and isotropic energy release are independently inconsistent with the larger short GRB population at >99.9% confidence. These properties, the host galaxies, and nondetection in gravitational waves …


Development Of Engineered Soil Surrogates For Modeling Natural Soil Sorption Behavior, Ghada Yehia Abdalla Jan 2021

Development Of Engineered Soil Surrogates For Modeling Natural Soil Sorption Behavior, Ghada Yehia Abdalla

LSU Doctoral Dissertations

The land produces more than 95% of the global food supply, and with a continuously growing population, we need to optimize the use of the available agricultural land. Soil organic matter (SOM) is an essential component of soils, especially concerning their fertility and sorption behavior. The chemical composition of the SOM consists of lipids, lignin, and cellulose. However, the heterogeneous and complex nature of SOM, and real soils, makes their study challenging and introduces uncontrollable factors.

Therefore, structural mimics of natural soils with increasing complexity representing the real soil functionality were synthesized and evaluated for bulk properties related to their …


A Conjecture On The Irregularity Function For Local Geometric Langlands Parameters And The Formal Frenkel-Gross Connection, Andrew Alaniz Jan 2021

A Conjecture On The Irregularity Function For Local Geometric Langlands Parameters And The Formal Frenkel-Gross Connection, Andrew Alaniz

LSU Doctoral Dissertations

For a simple complex algebraic group $G$, M. Kamgarpour and D. Sage have shown that the adjoint irregularity of an irregular singular flat $G$-bundle on the formal punctured disc is bounded from below by the rank of $G$, moreover the rank is realized by the formal Frenkel-Gross connection. This is a geometric analog of a conjecture of Gross and Reeder on the swan conductor of arithmetic local Langlands parameters. In this work, we explore an interesting combinatorial problem which arises when trying to consider the minimal value of the irregularity function with respect to an arbitrary representation of $G$.


The Tensile Root Strength Of Spartina Patens Declines With Exposure To Multiple Stressors, R. Eugene Turner, Lauris O. Hollis Jan 2021

The Tensile Root Strength Of Spartina Patens Declines With Exposure To Multiple Stressors, R. Eugene Turner, Lauris O. Hollis

Faculty Publications

Coastal wetlands may be subjected to numerous biotic and abiotic stressors from natural and anthropogenic forces in the landscape. The influx of nutrients, inorganic compounds and xenobiotics are suspected of degrading the belowground biomass of coastal macrophytes. Spartina patens acts as an ecosystem engineer for lower salinity coastal marshes and its biomechanical properties are vital to the stability and resilience of coastal wetlands. S.patens was exposed to one natural (flooding) and two anthropogenic stressors (atrazine and nutrient addition) in a greenhouse experiment to test the hypothesis that these three stressors reduce the tensile root strength of S. patens. A one-way …


Marginal Warming Associated With A Covid-19 Quarantine And The Implications For Disease Transmission, P. W. Miller, C. Reesman, M. K. Grossman, S. A. Nelson, V. Liu, P. Wang Jan 2021

Marginal Warming Associated With A Covid-19 Quarantine And The Implications For Disease Transmission, P. W. Miller, C. Reesman, M. K. Grossman, S. A. Nelson, V. Liu, P. Wang

Faculty Publications

During January-February 2020, parts of China faced restricted mobility under COVID-19 quarantines, which have been associated with improved air quality. Because particulate pollutants scatter, diffuse, and absorb incoming solar radiation, a net negative radiative forcing, decreased air pollution can yield surface warming. As such, this study (1) documents the evolution of China's January-February 2020 air temperature and concurrent particulate changes; (2) determines the temperature response related to reduced particulates during the COVID-19 quarantine (C19Q); and (3) discusses the conceptual implications for temperature-dependent disease transmission. C19Q particulate evolution is monitored using satellite analyses, and concurrent temperature anomalies are diagnosed using surface …


Distributed Load Testing By Modeling And Simulating User Behavior, Chester Ira Parrott Dec 2020

Distributed Load Testing By Modeling And Simulating User Behavior, Chester Ira Parrott

LSU Doctoral Dissertations

Modern human-machine systems such as microservices rely upon agile engineering practices which require changes to be tested and released more frequently than classically engineered systems. A critical step in the testing of such systems is the generation of realistic workloads or load testing. Generated workload emulates the expected behaviors of users and machines within a system under test in order to find potentially unknown failure states. Typical testing tools rely on static testing artifacts to generate realistic workload conditions. Such artifacts can be cumbersome and costly to maintain; however, even model-based alternatives can prevent adaptation to changes in a system …


Salt Marsh Elevation Limit Determined After Subsidence From Hydrologic Change And Hydrocarbon Extraction, R. Eugene Turner, Yu Mo Dec 2020

Salt Marsh Elevation Limit Determined After Subsidence From Hydrologic Change And Hydrocarbon Extraction, R. Eugene Turner, Yu Mo

Faculty Publications

Levee construction aboveground and hydrocarbon removal from belowground in coastal wetlands can create hydrologic changes that increase plant stress through flooding. But the significance of the subsidence they cause individually or in combination is contested. This study untangled them to demonstrate elevational limits of salt marshes by studying dredged and natural waterways in two salt marshes in Louisiana, USA. The areas had a homogenous plant cover before drilling for oil and gas extraction peaked in the 1960s, and now are a mixed network of natural waterways and dredged canals used to drill wells with an average drill date of 1965.8 …


A Nonstandard Proof Of De Finetti’S Theorem For Bernoulli Random Variables, Irfan Alam Dec 2020

A Nonstandard Proof Of De Finetti’S Theorem For Bernoulli Random Variables, Irfan Alam

Journal of Stochastic Analysis

No abstract provided.


The Boundedness Of General Alternative Singular Integrals With Respect To The Gaussian Measure, Eduard Navas, Ebner Pineda, Wilfredo O. Urbina Dec 2020

The Boundedness Of General Alternative Singular Integrals With Respect To The Gaussian Measure, Eduard Navas, Ebner Pineda, Wilfredo O. Urbina

Journal of Stochastic Analysis

No abstract provided.


Martingales And Cocycles In Quantum Probability, Kalyan B. Sinha Dec 2020

Martingales And Cocycles In Quantum Probability, Kalyan B. Sinha

Journal of Stochastic Analysis

No abstract provided.


Rényi Entropy On C*-Algebras, Farrukh Mukhamedov, Kyouhei Ohmura, Noboru Watanabe Dec 2020

Rényi Entropy On C*-Algebras, Farrukh Mukhamedov, Kyouhei Ohmura, Noboru Watanabe

Journal of Stochastic Analysis

No abstract provided.


Synthesis Of Structurally Diverse Molecular Scaffolds Enabled By Protected Oxyallyl Cations, Joshua Andrew Malone Dec 2020

Synthesis Of Structurally Diverse Molecular Scaffolds Enabled By Protected Oxyallyl Cations, Joshua Andrew Malone

LSU Doctoral Dissertations

This dissertation focuses on the synthesis of diverse molecular scaffolds through the use of protected oxyallyl cation intermediates. Chapter One provides background on the generation and applications of oxyallyl and silyloxyallyl cations, while focusing on the direct nucleophilic capture of theses intermediates to generate functionalized ketones and silylenolates. Chapter Two depicts our approach to generate six-membered silyloxyallyl cations through the use of mild Brønsted acid activation. Regioselective nucleophilic capture of these intermediates successfully produced diverse a,a’-substituted silylenol ethers enabled by polar solvent and residual water.

Chapter three details strategies to generate 1,4-dicarbonyl compounds, focusing on the capture of cationic intermediates …


R(P,Q) Analogs Of Discrete Distributions: General Formalism And Applications, Mahouton Norbert Hounkonnou, Fridolin Melong Dec 2020

R(P,Q) Analogs Of Discrete Distributions: General Formalism And Applications, Mahouton Norbert Hounkonnou, Fridolin Melong

Journal of Stochastic Analysis

No abstract provided.


The Yang-Mills Heat Equation On Three-Manifolds With Boundary, Nelia Charalambous Dec 2020

The Yang-Mills Heat Equation On Three-Manifolds With Boundary, Nelia Charalambous

Journal of Stochastic Analysis

No abstract provided.


Emergence Of Quantum Theories From Classical Probability: Historical Origins, Developments, And Open Problems, Luigi Accardi, Yun-Gang Lu Dec 2020

Emergence Of Quantum Theories From Classical Probability: Historical Origins, Developments, And Open Problems, Luigi Accardi, Yun-Gang Lu

Journal of Stochastic Analysis

No abstract provided.


An Asymptotic Formula For Integrals Of Products Of Jacobi Polynomials, Maxim Derevyagin, Nicholas Juricic Dec 2020

An Asymptotic Formula For Integrals Of Products Of Jacobi Polynomials, Maxim Derevyagin, Nicholas Juricic

Journal of Stochastic Analysis

No abstract provided.


On Subdiagonal Rational Pade Approximations And The Brenner-Thomee Approximation Theorem For Operator Semigroups, Frank Neubrander, Koray Ozer, Lee Windsperger Dec 2020

On Subdiagonal Rational Pade Approximations And The Brenner-Thomee Approximation Theorem For Operator Semigroups, Frank Neubrander, Koray Ozer, Lee Windsperger

Faculty Publications

The computational powers of Mathematica are used to prove polynomial identities that are essential to obtain growth estimates for subdiagonal rational Pade approximations of the exponential function and to obtain new estimates of the constants of the Brenner-Thomee Approximation Theorem of Semigroup Theory.


Covariant Quantum White Noise From Light-Like Quantum Fields, Radhakrishnan Balu Nov 2020

Covariant Quantum White Noise From Light-Like Quantum Fields, Radhakrishnan Balu

Journal of Stochastic Analysis

No abstract provided.


Measurements And Mitigation Of Scattered Light Noise In Ligo, Corey Daniel Austin Nov 2020

Measurements And Mitigation Of Scattered Light Noise In Ligo, Corey Daniel Austin

LSU Doctoral Dissertations

The Advanced LIGO (aLIGO) detectors use 1064 nm lasers to measure the tiny fluctuations in spacetime that occur when gravitational waves pass through the earth. LIGO makes use of advanced coating methods and materials to limit the amount of light that scatters from the main beam, but some amount of light does scatter. This stray light can interact with surfaces inside the interferometer that are not seismically isolated and then recombine with the main beam, introducing excess noise into the gravitational wave channel. This thesis reviews the methods for modeling scattered light with ray tracing software and analytical models, for …