Digital Commons Network^™

Density-Valued Solutions For The Boltzmann-Enskog Process, Christian Ennis, Barbara Rüdiger, Padmanabhan Sundar

Faculty Publications

The time evolution of a moderately dense gas evolving in vacuum described by the Boltzmann-Enskog equation is studied. The associated stochastic process, the Boltzmann-Enskog process, was constructed in [1] and further studied in [12, 13]. The process is given by the solution of a McKean-Vlasov equation driven by a Poisson random measure with the compensator depending on the distribution of the solution [1, 12]. The existence of a marginal probability density function at each time for the measure-valued solution is established in this article by using a functional-analytic criterion on Besov spaces [8, 11]. In addition to existence, the density …

Recovery Of The X-Ray Polarisation Of Swift J1727.8-1613 After The Soft-To-Hard Spectral Transition (Corrigendum) (Astronomy And Astrophysics (2024) 686 (L12) Doi: 10.1051/0004-6361/202450566), J. Podgorný, J. Svoboda, M. Dovčiak, A. Veledina, J. Poutanen, P. Kaaret, S. Bianchi, A. Ingram, F. Capitanio, S. R. Datta, E. Egron, H. Krawczynski, G. Matt, F. Muleri, P. O. Petrucci, T. D. Russell, J. F. Steiner, N. Bollemeijer, M. Brigitte, N. Castro Segura, R. Emami, J. A. García, K. Hu, M. N. Iacolina, V. Kravtsov, L. Marra, G. Mastroserio, T. Muñoz-Darias, E. Nathan, M. Negro, A. Ratheesh, N. Rodriguez Cavero, R. Taverna

Faculty Publications

(Figure presented) In Fig. 4, the X-ray hardness value for observation 8 was plotted using a count-based ratio instead of the energy-flux-based ratio used for other points in the figure. The correction of the position of this point in Fig. 4 does not affect any other figures, results, or conclusions in the paper.

Easyspec: An Open-Source Python Package For Long-Slit Spectroscopy, Raniere De Menezes, Francesco Massaro, Michela Negro, Claudia M. Raiteri, Harold Peña-Herazo, Jose A. Acosta-Pulido

Faculty Publications

In modern-day astronomy, near-infrared, optical, and ultraviolet spectroscopy are indispensable for studying a wide range of phenomena, from measuring black hole masses to analyzing chemical abundances in stellar atmospheres. However, spectroscopic data reduction is often performed using instrument-specific pipelines or legacy software well-established and robust within the community that are often challenging to implement and script in modern astrophysical workflows. In this work, we introduce easyspec, a new Python package designed for long-slit spectroscopy, capable of reducing, extracting, and analyzing spectra from a wide range of instruments—provided they deliver raw FITS files, the standard format for most optical telescopes worldwide. …

Sub-Gev Dark Matter And Mev Gamma-Ray Detection With Cosi, Yu Watanabe, Shigeki Matsumoto, Christopher M. Karwin, Tom Melia, Michela Negro, Thomas Siegert, Yuki Watanabe, Hiroki Yoneda, Tadayuki Takahashi

Faculty Publications

Sub-GeV dark matter (DM) has been attracting more attention due to the negative results searching for traditional weakly interacting massive particles (WIMPs). Such particles are expected to produce gamma rays from annihilation in the MeV energy region. Advancements in technology have opened up possibilities to precisely detect MeV gamma rays, leading to the upcoming space-based mission of the Compton Spectrometer and Imager (COSI). We comprehensively and quantitatively study the phenomenology of sub-GeV DM to determine if the COSI observations will probe their viable model parameter regions. We first construct models to describe sub-GeV DM based on the minimality and renormalizability …

Phase-Amplitude Separation Of Wave Function As Local Gauge Transformation, A. R.P. Rau

Faculty Publications

A quantum-mechanical wave function is complex, but all observations are real, expressible through expectation values and transition matrix elements that involve the wave functions. It can be useful to separate at the outset the amplitude and phase as real quantities that together carry the same information that is contained in the complex wave function. Two main avenues for doing so go way back in the history of the subject and have been used both for scattering and bound states. A connection is made here to gauge transformations of electrodynamics where the advent of quantum mechanics and later quantum field theory …

How The Inter-Nucleon Force Shapes Emergent Collectivity And Imparts Uncertainties In Ab Initio Nuclear Observables, Kevin Becker

LSU Doctoral Dissertations

The importance of collective motion in atomic nuclei has been well-established for many decades. Even before the advent of the nuclear shell model and its much-needed answers to surprising empirical phenomena, collectivity and surface deformation have played a vital role in broadening our knowledge. Reconciling the collective and single-particle camps into a unified description required tremendous strides in the application of group theory and advances in high-performance supercomputing, and thanks to these efforts the symmetry-adapted no-core shell model, or SA-NCSM, has developed into a reliable model for the study of deformed light and medium-mass nuclei. State-of-the-art calculations reveal remarkably simple …

Compound-Specific Isotope Records Of Dust Provenance And Hydroclimate In The North Pacific And Marginal Seas Of East Asia: Integrating N-Alkane Δ13c And Δd With Standardized Analytical Frameworks, Julian W. Traphagan

LSU Doctoral Dissertations

This dissertation presents advancements in compound-specific isotope analysis (CSIA) through methodological innovation and paleoclimate reconstruction in Central and East Asia. Utilizing plant wax n-alkanes from International Ocean Discovery Program (IODP) and Ocean Drilling Program (ODP) sediment cores, this research reconstructs atmospheric circulation shifts responding to tectonic evolution and climate transitions since the Late Miocene.

Chapter 1 investigates hydrogen isotope compositions (δD_wax) from IODP U1430 (Sea of Japan), ODP 886, and ODP 1208 (North Pacific) to trace dust provenance and hydroclimate changes since ~13 Ma. Results reveal persistently segmented source-to-sink systems: the Sea of Japan dominated by westerly …

Effects Of Cryoprotective And Mitochondrial Stabilizing Agents On Vitrified Bovine Oocytes, Allison Hoang

LSU Master's Theses

Oocyte vitrification success is highly dependent on cryoprotectant agent (CPA) choice as well as possible additives that could help preserve mitochondrial membrane potential (mMP), reactive oxygen species (ROS) production, and calcium homeostasis within the cell. It is a delicate balance between levels needed for proper oocyte function and activation and levels needed to induce apoptotic pathways. The results of oocyte cryopreservation determine the eventual oocyte viability and subsequent fertilization and embryo development.

In this study potential permeating cryoprotectant combinations were explored such as ethylene glycol (EG) and propylene glycol (PG) or EG in combination with dimethyl sulfoxide (DMSO). Also, the …

Investigation Of Co-Current And Counter-Current Multiphase Flow In Upstream Drilling And Production Applications, Hazem Fleifel

LSU Doctoral Dissertations

In the domain of upstream Petroleum Engineering, the dynamics of co-current and counter-current multiphase flows present huge challenges, significantly impacting the efficiency of associated processes. This study investigates two specific applications concerning these flow behaviors, involving both laboratory experiments and transient computer simulations. This work investigates two distinct well control and production enhancement processes, involving multiphase flow dynamics: the bullheading kill procedure and liquid-assisted gas lift (LAGL).

The first topic (Topic 1) explores the bullheading process, a type of well control methods, by challenging the traditional understanding that gas removal efficiency increases monotonically with injection pump flow rate. Through 1D …

Catalyst Compositions For Hydroformylation And Methods Of Use Thereof, George Stanley, Drew Hood

College of Science Patents

No abstract provided.

Methods And Devices For Sample Capture Using Gas-Pulse Nanoparticle Displacement, Kermit King Murray, Fabrizio Donnarumma, Jamira Stephenson

College of Science Patents

The present disclosure provides for sampling instruments and methods of collecting sample particles. The sampling instrument can include a high-pressure pulsed valve coupled to a gas flow system to displace a sample from a surface. Also included can be a voltage supply coupled to a voltage switch, a suction device, a sample collector, and a collection filter. To collect a sample, extractive particles can be deposited onto a sample present on a substrate. At least a portion of the sample becomes coupled to a portion of the extractive particles to form sample particles. High-pressure gas can be discharged at the …

Feral Hog Toxicant, Glen Gentry, John Pojman, Baylen Thompson

LSU AgCenter Patents

A composition and method for killing feral hogs: a bait that is attractive to hogs is mixed with a lethal amount of sodium nitrite, along with sufficient base to inhibit decomposition of the sodium nitrite. At sufficiently high pH, encapsulation of the sodium nitrite is not required to inhibit decomposition. In the absence of substantial decomposition, the sodium nitrite itself is not aversive to the pigs, and may even enhance acceptance of the baits by the pigs. Optionally, an anti-emetic compound is added to the mixture to reduce the likelihood the bait will be vomited. Optionally, an additional toxicant such …

Learning Neural Point Processes For Long Event Sequences, Zhuoqun Li

LSU Doctoral Dissertations

This research presents a comprehensive series of studies aimed at advancing learning neural point processes for long event sequences, with applications spanning disaster resilience, crime forecasting, and healthcare. Structured around three interconnected studies, this work addresses core challenges in temporal point process (TPP) modeling, efficient handling of long event sequences, and improving accuracy over extended forecasting horizons by reinforcement learning.

The first study proposes the Sparse Transformer Hawkes Process (STHP) to model long asynchronous event sequences. Traditional neural network-based TPPs struggle with long event sequences due to computational inefficiencies. To address this, the STHP model combines two components: a temporal …

Designing A Data Collection And Visualization Toolkit For Scalable Tensor Algebra In Quantum Chemistry Applications, Epiya J. Ebiapia

LSU Master's Theses

Large-scale quantum chemistry computations, such as those executed with the Tensor Algebra for Many-body Methods (TAMM) framework, require careful configuration of runtime parameters to achieve high performance and cost efficiency in high-performance computing (HPC) and cloud environments. Without effective performance analysis tools, researchers risk inefficient use of computational resources, leading to longer runtimes and higher costs.

To address this challenge, this thesis presents the design and implementation of a performance profiling and visualization toolkit for TAMM, developed as part of the DOE TEC4 project in collaboration with Pacific Northwest National Laboratory, Microsoft, and Louisiana State University. The toolkit collects detailed …

Tense And Agreement Measures In Young African American English-Speaking Children, Kwaku Nyantakyi

LSU Doctoral Dissertations

The Tense Marker Total (TMT) and the Tense and Agreement Productivity (TAP) score are two ways of measuring children’s tense and agreement systems, and studies have shown that both measures track developmental growth across different ages in General American English (GAE)-speaking children. This dissertation examined the feasibility and validity of using these measures for children learning African American English (AAE).

The data were cross-sectional archival language samples from 38 AAE-speaking children who ranged in age from three to five years (11 at 3 years, 12 at 4 years, 15 at 5 years). The language samples were coded and scored for …

Examining Multi-Level Support-Related Factors Influencing School-Based Mental Health Services Across Various Types Of U.S. Public High Schools, Wendy L. Wilson

LSU Doctoral Dissertations

Youth mental health is a global and national public health issue, with notable disparities in access to school-based mental health services (SBMHS; Kieling et al., 2024). This highlights the urgent need to identify supportive factors that can enhance service availability within educational settings. This cross-sectional, exploratory-descriptive study aimed to identify multi-level support-related factors (SRFs) at the student, school, and community levels that best predict SBMHS availability across different types of U.S. public high schools. The researcher conducted a secondary data analysis of a sample of 855 respondents who completed the 2017-18 School Survey on Crime and Safety. Various univariate, bivariate, …

Exploring Longitudinal Stability Of Spatiotemporal Sequential Patterns By Means Of Autoencoder Schemes For Eeg Based Personal Identification, Muhammed E. Oztemel

LSU Doctoral Dissertations

Robust personal identification remains a critical and challenging task in the digital era. Electroencephalography (EEG) offers a unique biometric modality that captures individual brain dynamics through complex neural signals. This dissertation proposes autoencoder (AE) based feature extraction and subject identification through these features. EEG recordings are first transformed into topographic maps to represent spatial brain activity. Consecutive topomaps are then concatenated to capture temporal transitions across frames. Convolutional autoencoders (CAEs) are used to learn spatial and temporal patterns, while domain-adaptive AEs are designed to model evoked potential based responses. Additionally, self-attention mechanism is incorporated to enhance feature representation. To analyze …

Pinch: Pipeline-Informed Noise Characterization In Ligo’S Third Observing Run, Zach Yarbrough, Andre Guimaraes, Prathamesh Joshi, Gabriela González, Andrew Valentini

Faculty Publications

We present a method to identify and categorize gravitational wave candidate triggers identified by matched filtering gravitational wave searches (pipelines) caused by transient noise (glitches) in gravitational wave detectors using support vector machine (SVM) classifiers. Our approach involves training SVM models on pipeline triggers which occur outside periods of excess noise to distinguish between triggers caused by random noise and those induced by glitches. This method is applied independently to the triggers produced by the GstLAL search pipeline on data from the laser interferometer gravitational-wave observatory Hanford and Livingston observatories during the second half of the O3 observing run. The …

Timing And Spectral Evolution Of The Magnetar 1e 1841-045 In Outburst, George Younes, Samuel K. Lander, Matthew G. Baring, Marlon L. Bause, Rachael Stewart, Zaven Arzoumanian, Hoa Dinh Thi, Teruaki Enoto, Keith C. Gendreau, Tolga Güver, Alice K. Harding, Wynn C.G. Ho, Chin Ping Hu, Alex Van Kooten, Chryssa Kouveliotou, Niccolò Di Lalla, Alexander Mcewen, Michela Negro, Mason Ng, David M. Palmer, Laura G. Spitler, Zorawar Wadiasingh

Faculty Publications

We present timing and spectral analyses of Neutron star Interior Composition Explorer (NICER), Nuclear Spectroscopic Telescope Array (NuSTAR), and IXPE observations of the magnetar 1E 1841−045 covering 82 days following its 2024 August bursting activity as well as radio observations utilizing MeerKAT and Effelsberg. We supplement our study with a historical NuSTAR observation and all 2024 preoutburst NICER observations. The outburst is marked by an X-ray flux enhancement of a factor of 1.6 compared to the historical level, predominantly driven by a newly formed nonthermal emitting component with a photon index Γ = 1.5. This flux showed a 20% decay …

Puzzling Variation Of Gamma Rays From The Sun Over The Solar Cycle Revealed With Fermi-Lat, A. Acharyya, A. Adelfio, M. Ajello, L. Baldini, C. Bartolini, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, B. Berenji, E. Bissaldi, R. D. Blandford, R. Bonino, E. Bottacini, S. Buson, R. A. Cameron, P. A. Caraveo, F. Casaburo, F. Casini, E. Cavazzuti, D. Cerasole, N. Cibrario, S. Ciprini, G. Cozzolongo, P. Cristarella Orestano, F. Cuna, A. Cuoco, S. Cutini, F. D’Ammando, D. Depalo, S. W. Digel, N. Di Lalla, L. Di Venere, A. Domínguez

Faculty Publications

The steady-state gamma-ray emission from the Sun is thought to consist of two emission components due to interactions with Galactic cosmic rays: (1) a hadronic disk component, and (2) a leptonic extended component peaking at the solar edge and extending into the heliosphere. The flux of these components is expected to vary with the 11 yr solar cycle, being highest during solar minimum and lowest during solar maximum, as it varies with the cosmic-ray flux. No study has yet analyzed the flux variation of each component over solar cycles. In this work, we measure the temporal variations of the flux …

The Characteristic Function Of The Cube Of A Gaussian Random Variable, Andreas Boukas

Journal of Stochastic Analysis

Using the spectral resolution of the multiplication operator on the Schwartz class of L2(R,C), we compute the characteristic function of the cube of a Gaussian random variable.

The Multiband Imaging Survey For High-Alpha Planets (Mishaps). I. Preliminary Constraints On The Occurrence Rate Of Hot Jupiters In 47 Tucanae, Alison L. Crisp, Jonas Klüter, Marz L. Newman, Matthew T. Penny, Thomas G. Beatty, L. Ilsedore Cleeves, Karen A. Collins, Jennifer A. Johnson, Marshall C. Johnson, Michael B. Lund, Clara E. Martínez-Vázquez, Melissa K. Ness, Joseph E. Rodriguez, Robert Siverd, Daniel J. Stevens, Steven Villanueva, Carl Ziegler

Faculty Publications

The first generation of transiting planet searches in globular clusters yielded no detections, and in hindsight only placed occurrence rate limits slightly higher than the measured occurrence rate in the higher-metallicity Galactic thick disk. To improve these limits, we present the first results of a new wide-field search for transiting hot Jupiters in the globular cluster 47 Tucanae (47 Tuc). We have observed 47 Tuc as part of the Multiband Imaging Survey for High-Alpha PlanetS. Using 24 partial and full nights of observations taken with the Dark Energy Camera on the 4 m Blanco telescope at Cerro-Tololo Interamerican Observatory, we …

Deltaic Engineering-Induced Accumulation Hides Erosion In Response To Fluvial Sediment Decline In The Yangtze Submarine Shoal, Haifei Yang, Lu Wang, Kehui Xu, Wenxiang Zhang, Benwei Shi, Shilun Yang, Ya Ping Wang

Faculty Publications

Worldwide river deltas are impacted by human activities and climatic change, but it has been challenging to quantify their contributions due to nonlinear natural processes and a lack of long-term geomorphological data. Time-series bathymetric data were collected at submarine Hengsha Shoal in the Yangtze Delta during 11 repeat surveys over 60 yr. Our results show that the minimum riverine sediment supply to maintain the shoal's morphology was 229–258 Mt yr⁻¹. Without human impacts, it would have been experiencing net erosion since the operation of the Three Gorges Dam in 2003. However, this shoal has been growing in certain …

Impact Of River Reconnection For Coastal Restoration On Nitrate Reduction In Brackish Marsh Soils And Bay-Bottom Sediments In Coastal Louisiana, Usa, Mercedes M. Pinzón, John R. White

Faculty Publications

Wetlands provide important ecosystem services, including improving surface water quality through nutrient removal. Louisiana has experienced ~ 4800 km² of coastal wetland loss between 1932 and 2016 due to high relative sea level rise and reduced sediment from the Mississippi River due to levees. The 2023 LA Coastal Master Plan aims to restore Louisiana’s degraded coastline through restoration projects, including sediment diversions or river reconnection. The Mid-Barataria Sediment Diversion Project will reconnect the river sediment-laden water with the coastal wetlands of Barataria Basin to nourish degrading marshes. However, the diversion will also deliver substantial nitrate (NO3⁻) to …

Subtropical Marine Cloud Brightening Suppresses The El Niño–Southern Oscillation, C. Xing, S. Stevenson, J. Fasullo, C. Harrison, C. Chen, J. Wan, J. Coupe, C. Pfleger

Faculty Publications

Stratospheric aerosol injection (SAI) and marine cloud brightening (MCB) are two proposed methods of compensating for greenhouse gas-induced warming by reflecting incoming solar radiation. However, their effects on the El Niño–Southern Oscillation (ENSO), a critical mode of climate variability, are poorly understood. Here we use ensembles of climate model simulations to show that deploying MCB in the subtropical eastern Pacific dramatically reduces ENSO amplitude by approximately 61%, while SAI has a negligible impact. MCB increases cloud albedo, which cools the subtropical eastern Pacific and triggers a loss of moist static energy. This cooling promotes atmospheric subsidence, dries the tropical Pacific, …

Rate Of Sea-Level Rise And Sediment Characteristics Modulate Deltaic River-Tide Interactions, Peter Bacopoulos, Celalettin E. Ozdemir, Matthew Hiatt

Faculty Publications

Due to sea-level rise, small river-dominated deltas (< 100 km²) are expected to become more exposed to tidal influences in the future. However, there remains a knowledge gap in the impending hydrodynamics of such deltas, particularly with the interactions between river and tidal flows. In addition to sea-level rise, river-tide interactions in these deltas depend on their morphology, which is influenced by the sand proportion in the particulate matter delivered by rivers. This study investigates river-tide interactions predicted for small deltas formed by different sand-to-mud ratios under various sea-level rise scenarios. Delta morphologies were generated using reduced-order complexity model (DeltaRCM), …

Novel Sequential Modeling Framework Improves Phytoplankton Biomass Predictions In Response To Multiple Environmental Stressors, Zhuyin Tong, Jiayu Guo, Yikai Liu, Lizhen Lin, Jixin Chen, Xin Liu, Bangqin Huang, Edward A. Laws, Wupeng Xiao

Faculty Publications

Understanding the impacts of multiple environmental stressors on phytoplankton biomass is crucial for predicting marine ecosystem responses under global climate change. This study employed a sequential modeling framework integrating principal component analysis, generalized additive models, and artificial neural networks to improve predictions of phytoplankton chlorophyll a concentrations in the Taiwan Strait. Analyzing a decadal dataset, we found that a 2°C rise in sea surface temperature and a 0.2 pH decline will each lead to an 11.3% reduction in chlorophyll a biomass, whereas nitrogen enrichment is expected to increase it by only 2.8%. The combined effects of these stressors will result …

Cell Death Helps To Stabilize Populations Of Prochlorococcus, P. Wang, E. A. Laws, C. Liang, X. Liu, J. Chen, Y. Zhong, C. Li, B. Huang

Faculty Publications

Prochlorococcus is one of the dominant phytoplankton species in tropical and subtropical pelagic marine ecosystems. To maintain its population equilibrium in oligotrophic waters, the dominant species Prochlorococcus requires high loss rates to offset its high abundance and growth rates. While theoretical frameworks recognize multiple loss processes for Prochlorococcus (viral lysis, environmental stress, programmed cell death), prevailing population studies attribute main mortality to grazing. This oversight stems from in situ data gaps of non-grazing mortality processes. In this study, we firstly formulated simple differential equations that took account of population losses due to both grazing and cell death. We then used …

Detected Abundances Of Nuclei Relative To 26fe For Elements 14si Through 44ru With Calet On The International Space Station, O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, P. Betti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, G. A. De Nolfo, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo

Faculty Publications

The Calorimetric Electron Telescope (CALET), launched to the International Space Station (ISS) in 2015 August and continuously operating since, measures cosmic-ray (CR) electrons, nuclei, and gamma rays. CALET, with its 27 radiation length deep Total Absorption Calorimeter, measures particle energy and allows for the measurement of spectra, secondary to primary ratios of the more abundant CR nuclei through 28Ni, while the main charge detector can measure ultra-heavy CR nuclei through 44Ru. The results for the abundances of elements from Z = 14 to Z = 44 relative to 26Fe over 7.5 yr of observation are presented here and compared to …

From Poverty Trap To Commodity Trap: Entrepreneurship And Well-Being Among The Poor, Michael H. Morris, Sohrab Soleimanof, Marcello Calle, Reginald Tucker

Faculty Publications

Building on disadvantage theory and the capabilities framework, the research explores how two critical aspects of the poverty experience, experienced scarcity, and a limited opportunity horizon, can result in the creation of ventures that struggle to achieve marketplace success, which in turn detracts from the entrepreneur’s perceived well-being. These business struggles are traced to a commodity trap, where the business is not well differentiated in the marketplace, suffers from low volumes and margins, has little bargaining power, and is labor-intensive and capacity-constrained. A set of hypotheses regarding these relationships are tested using data from a sample of entrepreneurs from poverty …