Digital Commons Network^™

The Relative Importance Of Local And Regional Processes To Metapopulation Dynamics, Tad A. Dallas, Marjo Saastamoinen, Torsti Schulz, Otso Ovaskainen

Faculty Publications

© 2019 The Authors. Journal of Animal Ecology © 2019 British Ecological Society Metapopulation dynamics – patch occupancy, colonization and extinction – are the result of complex processes at both local (e.g. environmental conditions) and regional (e.g. spatial arrangement of habitat patches) scales. A large body of work has focused on habitat patch area and connectivity (area-isolation paradigm). However, these approaches often do not incorporate local environmental conditions or fully address how the spatial arrangement of habitat patches (and resulting connectivity) can influence metapopulation dynamics. Here, we utilize long-term data on a classic metapopulation system – the Glanville fritillary butterfly …

Guiding And Trapping Cracks With Compliant Inclusions For Enhancing Toughness Of Brittle Composite Materials, Neal R. Brodnik, Chun Jen Hsueh, Katherine T. Faber, Blaise Bourdin, Guruswami Ravichandran, Kaushik Bhattacharya

Faculty Publications

The problem of toughening heterogeneous materials with a stiff matrix and compliant inclusions is investigated through numerical simulations and experiments. Specifically, the problem of optimizing a combination of effective toughness and effective elastic modulus in the context of a square array of compliant inclusions in a stiff matrix is explored. Crack propagation in the heterogeneous material is simulated using a variational phase-field approach. It is found that the crack can meander between or get attracted to and trapped in the inclusions. Composite specimens with a stiff matrix and compliant circular inclusions were 3D printed, and their fracture toughness was measured …

Ranking Tournaments With No Errors I: Structural Description, Xujin Chen, Guoli Ding, Wenan Zang, Qiulan Zhao

Faculty Publications

In this series of two papers we examine the classical problem of ranking a set of players on the basis of a set of pairwise comparisons arising from a sports tournament, with the objective of minimizing the total number of upsets, where an upset occurs if a higher ranked player was actually defeated by a lower ranked player. This problem can be rephrased as the so-called minimum feedback arc set problem on tournaments, which arises in a rich variety of applications and has been a subject of extensive research. In this series we study this NP-hard problem using structure-driven and …

Reflection Positivity On Spheres, Karl Hermann Neeb, Gestur Ólafsson

Faculty Publications

In this article we specialize a construction of a reflection positive Hilbert space due to Dimock and Jaffe–Ritter to the sphere Sn. We determine the resulting Osterwalder–Schrader Hilbert space, a construction that can be viewed as the step from euclidean to relativistic quantum field theory. We show that this process gives rise to an irreducible unitary spherical representation of the orthochronous Lorentz group Gc= O 1,n(R) ↑ and that the representations thus obtained are the irreducible unitary spherical representations of this group. A key tool is a certain complex domain Ξ , known as the crown of the hyperboloid, containing …

North Atlantic Hurricane Winds In Warmer Than Normal Seas, Jill C. Trepanier

Faculty Publications

Tropical cyclones devastate coastlines around the world. The United States and surrounding areas experienced catastrophic extreme events in recent hurricane seasons. Understanding extreme hurricanes and how they change in a warming ocean environment is of the utmost importance. This study makes use of the historical, positive relationship between average summer sea surface temperatures (SSTs) and maximum hurricane wind speeds across the North Atlantic Basin from 1854-2018. Geographically weighted regression shows how the relationship between hurricane winds and SSTs varies across space. Each localized slope is used to increase historical wind speeds to represent winds in a three-degree Celsius warmer-than-average sea …

20 Years Of Evolution From Cognitive To Intelligent Communications, Zhijin Qin, Xiangwei Zhou, Lin Zhang, Yue Gao, Ying Chang Liang, Geoffrey Ye Li

Faculty Publications

It has been 20 years since the concept of cognitive radio (CR) was proposed, which is an efficient approach to provide more access opportunities to connect massive wireless devices. To improve the spectrum efficiency, CR enables unlicensed usage of licensed spectrum resources. It has been regarded as the key enabler for intelligent communications. In this article, we will provide an overview on the intelligent communication in the past two decades to illustrate the revolution of its capability from cognition to artificial intelligence (AI). Particularly, this article starts from a comprehensive review of typical spectrum sensing and sharing, followed by the …

Large And Moderate Deviation Principles For Recursive Kernel Estimators For Spatial Data, Salim Bouzebda, Yousri Slaoui

Journal of Stochastic Analysis

No abstract provided.

Ecogeomorphic Evolution Of Muddy Coastlines: How Biota On A Range Of Scales, From Microscopic Biofilms To Landscape-Scale Vegetation Zonation Patterns, Interact With Physical Processes, Kendall Cole

LSU Doctoral Dissertations

Coastal wetland ecosystems are inherently interdisciplinary; in these spaces, the physical forces of wind and water meet to interact with stabilizing and fortifying vegetation and biota, as well as mud. The combination of these factors build and sustain wetland ecosystems and without the complex feedbacks, they would cease to exist. In this dissertation, I present three studies that focus on ecogeomorphic interactions within coastal wetlands on a range of scales, from microscopic to the entire landscape and highlight the importance of these interactions when predicting future coastal change. The first study examined how biofilms, matrixes of photosynthetic diatoms and their …

Closed Quantum Black-Scholes: Quantum Drift And The Heisenberg Equation Of Motion, Will Hicks

Journal of Stochastic Analysis

No abstract provided.

Three Essays On The Economics Of Education, Tianheng Wang

LSU Doctoral Dissertations

This dissertation consists of three essays related to the field of economics of education. In chapter 2, using data from middle school students in China and exploiting the random assignment of students to classrooms within schools, I investigate the causal effect of peer groups on students’ scholastic achievement. I find that female student proportion in the classroom positively affects male students’ test scores and that the education level of peers’ parents improves the academic achievement of both male and female students. Students with highly-educated parents benefit more from classmates with higher parental education compared to students with relatively lower parental …

Simulating Wave Dynamics In The Northern Gulf Of Mexico And Barataria Pass, Azadeh Razavi Arab

LSU Master's Theses

The coastal wetlands of Louisiana constitute ~40% of the wetlands in the United States. However, it suffers from 80% of the wetland losses in the whole country. In shallow coastal and estuarine environments, bed shear stresses related to wind waves contributes substantially to the edge erosion in the northern Gulf of Mexico (NGoM). Therefore, wave simulations in shallow estuarine areas are of great importance.

There are several challenges in simulating waves nearshore, especially over the shallow and nearly horizontal sea beds typical of the NGoM continental shelf and adjacent complex geometry estuaries: determination of the appropriate wind forcing dataset to …

Improving Ocr Accuracy Of Damaged Pictures With Generative Adversarial Networks, Pu Du

LSU Master's Theses

In this thesis, we focus on resolving the inpainting problem and improving Optical Character Recognition (OCR) accuracy of damaged text images at character level. We present a Generative Adversarial Network (GAN)-based model conditioned on class labels for image inpainting. This model is a deep convolutional neural network with encoder-decoder style architecture which can process images with holes at random locations. Experiments on the character images dataset demonstrate that our proposed model generates promising inpainting results and significantly improve OCR accuracy by reconstructing missing parts of damaged character images.

Mass Spectrometric Calibration For Real -Time Hydrocarbon Detection, Makuachukwu Mbaegbu

LSU Master's Theses

Determining gas compositions from live well fluids on a drilling rig is critical for real time formation evaluation. However, development and utilization of a reliable mass spectrometric method to accurately characterize these live well fluids is always a challenging issue because of lack of a robust, quick and effectively selective instrument and method. The primary goal of this research is to understand reasons of such discrepancies in results between “good” spectra, and “poor” ones. The objectives are thus to identify the detection issues, calibrate and QA/QC the instruments, and analyze the results in lab settings. In this study, we used …

Role Of Coastal Environmental Conditions During Austral Winter On Plankton Community Dynamics And The Occurrence Of Pseudo-Nitzschia Spp. And Domoic Acid In Inhambane Province, Mozambique, Holly Kelchner

LSU Master's Theses

Harmful algal blooms (HABs) are increasing globally in frequency, persistence, and geographic extent. HABs pose a threat to economic stability, and ecosystem and human health. To date no incidences of marine toxins produced by phytoplankton have been recorded in Mozambique, which may be due to the absence of a monitoring program and general awareness of the potential threat. This study is the first documentation of the occurrence of a neurotoxin, domoic acid (DA), produced by the diatom genus Pseudo-nitzschia spp. along the east coast of Africa. The coast of Inhambane Province is a biodiversity hotspot where year-round Rhincodon typus (whale …

Introduction To Computational Thinking: A New High School Curriculum Using Codeworld, Fernando Alegre, John Underwoood, Juana Moreno

Faculty Publications

The Louisiana Department of Education partnered with the Gordon A. Cain Center at LSU to pilot a Computing High School Graduation Pathway. The first course in the pathway, Introduction to Computational Thinking (ICT), is designed to teach programming and reinforce mathematical practice skills of nine-grade students, with an emphasis on promoting higher order thinking. In 2017- 18, about 200 students and five teachers participated in the pilot, in 2018-2019 the participation increased to 400 students, and in the current 2019-2020 year about 800 students in 11 schools are involved. After describing the course content and the teacher training, we briefly …

Critical Collapse Of A Scalar Field In Semiclassical Loop Quantum Gravity, Florencia Benítez, Rodolfo Gambini, Luis Lehner, Steve Liebling, Jorge Pullin

Faculty Publications

We study the collapse in spherical symmetry of a massless scalar field minimally coupled to gravity using the semiclassical equations that are expected from loop quantum gravity. We find the critical behavior of the mass as a function of the parameters of the initial data similar to that found by Choptuik in classical general relativity for a large set of initial data and values of the polymerization parameter. Contrary to wide expectations for quantum gravity, our semiclassical field equations have an exact scale invariance, as do the classical field equations. As one would then expect, we numerically find that the …

Exit Problems For Jump-Diffusion Processes With Uniform Jumps, Mario Lefebvre

Journal of Stochastic Analysis

No abstract provided.

Attosecond Pulse Shaping Using A Seeded Free-Electron Laser, Praveen Kumar Maroju, Cesare Grazioli, Michele Di Fraia, Matteo Moioli, Dominik Ertel, Hamed Ahmadi, Oksana Plekan, Paola Finetti, Enrico Allaria, Luca Giannessi, Giovanni De Ninno, Carlo Spezzani, Giuseppe Penco, Simone Spampinati, Alexander Demidovich, Miltcho B. Danailov, Roberto Borghes, George Kourousias, Carlos Eduardo Sanches Dos Reis, Fulvio Billé, Alberto A. Lutman, Richard J. Squibb, Raimund Feifel, Paolo Carpeggiani, Maurizio Reduzzi, Tommaso Mazza, Michael Meyer, Samuel Bengtsson, Neven Ibrakovic, Emma Rose Simpson, Johan Mauritsson, Tamás Csizmadia, Mathieu Dumergue

Faculty Publications

Attosecond pulses are central to the investigation of valence- and core-electron dynamics on their natural timescales1–3. The reproducible generation and characterization of attosecond waveforms has been demonstrated so far only through the process of high-order harmonic generation4–7. Several methods for shaping attosecond waveforms have been proposed, including the use of metallic filters8,9, multilayer mirrors10 and manipulation of the driving field11. However, none of these approaches allows the flexible manipulation of the temporal characteristics of the attosecond waveforms, and they suffer from the low conversion efficiency of the high-order harmonic generation process. Free-electron lasers, by contrast, deliver femtosecond, extreme-ultraviolet and X-ray …

The Influence Of Personality And Losses On Search In Decisions From Experience, Michael Mordechai Hay

LSU Master's Theses

Research in decision making has focused increasing attention on understanding search behavior without focusing on how individual differences might influence people’s search behavior. To increase our understanding of this topic, the present study examined how personality predicted the amount of search an individual engages in before making a risky decision. It was hypothesized that conscientiousness would be a positive predictor of search behavior and would emerge as an even stronger predictor of search behavior when choosing between options with negative outcomes. It was also hypothesized that neuroticism would be a negative predictor of search behavior and that individuals with higher …

Ogawa Integrability And A Condition For Convergence In The Multidimensional Case, Nicolò Cangiotti, Sonia Mazzucchi

Journal of Stochastic Analysis

No abstract provided.

Assessment Of Soil Protein And Refractory Soil Organic Matter Across Two Chronosequences Of Newly Developing Marshes In Coastal Louisiana, Usa, Stuart Alexander Mcclellan

LSU Doctoral Dissertations

The impacts of sea-level rise and hydrologic manipulation are threatening the stability of coastal marshes throughout the world, thereby increasing the potential for re-mineralization of soil organic matter (SOM) in these systems. Such threats have prompted marsh restoration efforts, particularly in coastal Louisiana, yet it is unclear how the slowly decomposing (refractory) and quickly decomposing (labile) fractions of SOM may be differentially affected by different approaches to marsh restoration. Additionally, otherwise labile compounds may accumulate in the soil via a range of protective mechanisms, including rapid burial and association with organic compounds that are thought to enhance soil aggregation, such …

Mixing Coefficient For Discrete-Time Stochastic Flow, E.V. Glinyanaya

Journal of Stochastic Analysis

No abstract provided.

On A Class Of Average Preserving Semi-Martingale Laws Optimization Problems, Rémi Lassalle

Journal of Stochastic Analysis

No abstract provided.

Conditional Quantum One-Time Pad, Kunal Sharma, Eyuri Wakakuwa, Mark M. Wilde

Faculty Publications

Suppose that Alice and Bob are located in distant laboratories, which are connected by an ideal quantum channel. Suppose further that they share many copies of a quantum state ρABE, such that Alice possesses the A systems and Bob the BE systems. In our model, there is an identifiable part of Bob's laboratory that is insecure: a third party named Eve has infiltrated Bob's laboratory and gained control of the E systems. Alice, knowing this, would like use their shared state and the ideal quantum channel to communicate a message in such a way that Bob, who has access to …

The Semimartingale Dynamics And Generator Of A Continuous Time Semi-Markov Chain, Robert J. Elliott

Journal of Stochastic Analysis

No abstract provided.

A Guide To Ligo-Virgo Detector Noise And Extraction Of Transient Gravitational-Wave Signals, B. P. Abbott, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, T. Alford, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda, M. Ar Ne, N. Arnaud

Faculty Publications

The LIGO Scientific Collaboration and the Virgo Collaboration have cataloged eleven confidently detected gravitational-wave events during the first two observing runs of the advanced detector era. All eleven events were consistent with being from well-modeled mergers between compact stellar-mass objects: black holes or neutron stars. The data around the time of each of these events have been made publicly available through the gravitational-wave open science center. The entirety of the gravitational-wave strain data from the first and second observing runs have also now been made publicly available. There is considerable interest among the broad scientific community in understanding the data …

Expectation Values Of Coherent States For Su(2) Lattice Gauge Theories, Klaus Liegener, Ernst-Albrecht Zwicknagel

Faculty Publications

This article investigates properties of semiclassical Gauge Field Theory Coherent States for general quantum gauge theories. Useful, e.g., for the canonical formulation of Lattice Gauge Theories these states are labelled by a point in the classical phase space and constructed such that the expectation values of the canonical operators are sharply peaked on said phase space point. For the case of the non-abelian gauge group SU(2), we will explicitly compute the expectation value of general polynomials including the first order quantum corrections. This allows asking more precise questions about the quantum fluctuations of any given semiclassical system.

Understory Vegetation Richness And Diversity Of Eucalyptus Benthamii And Pinus Elliottii Plantations In The Midsouth Us, Andrea De Stefano, Michael A. Blazier, Christopher E. Comer, Thomas J. Dean, T. Bently Wigley

Faculty Publications

In the Western Gulf region of the United States cold-tolerant eucalyptus have been explored as pulpwood feedstock. However, non-native plantations may alter understory species diversity, modifying environmental conditions and soil characteristics. Few studies have compared eucalyptus plantations with native ecosystems to understand the impact on understory vegetation in the United States. In this study, we compared understory plant species richness and diversity during 2014-2016 in (1) slash pine (Pinus elliottii) established in 2008, (2) slash pine established in 2013, and (3) and Camden white gum (Eucalyptus benthamii) established in 2013. Overstory characteristics, soil pH, and soil nutrient concentrations were measured …

Optimal Uniform Continuity Bound For Conditional Entropy Of Classical–Quantum States, Mark M. Wilde

Faculty Publications

In this short note, I show how a recent result of Alhejji and Smith (A tight uniform continuity bound for equivocation, 2019. arXiv:1909.00787v1) regarding an optimal uniform continuity bound for classical conditional entropy leads to an optimal uniform continuity bound for quantum conditional entropy of classical–quantum states. The bound is optimal in the sense that there always exists a pair of classical–quantum states saturating the bound, and so, no further improvements are possible. An immediate application is a uniform continuity bound for the entanglement of formation that improves upon the one previously given by Winter (Commun Math Phys 347(1):291–313, 2016. …

Mixed Perverse Sheaves On Flag Varieties For Coxeter Groups, Pramod N. Achar, Simon Riche, Cristian Vay

Faculty Publications

In this paper we construct an abelian category of mixed perverse sheaves attached to any realization of a Coxeter group, in terms of the associated Elias-Williamson diagrammatic category. This construction extends previous work of the first two authors, where we worked with parity complexes instead of diagrams, and we extend most of the properties known in this case to the general setting. As an application we prove that the split Grothendieck group of the Elias-Williamson diagrammatic category is isomorphic to the corresponding Hecke algebra, for any choice of realization.