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Charting The Course To Advance Dei In The Ocean Sciences A Case Study, Christopher F. D’Elia, Katherine Falls, Sibel Bargu, Linda Hooper-Bùi Jan 2023

Charting The Course To Advance Dei In The Ocean Sciences A Case Study, Christopher F. D’Elia, Katherine Falls, Sibel Bargu, Linda Hooper-Bùi

Faculty Publications

The Louisiana State University College of the Coast & Environment (LSU CC&E) developed a multi-faceted strategic initiative to increase its diversity, equity, and inclusion. Elements of this initiative began one-by-one over the last decade and were aggregated into a comprehensive implementation plan—the 2020 CC&E Diversity, Equity, and Inclusion Action Plan. Based on best practices in the “physical sciences” (i.e., geosciences, including oceanography), the plan aims to augment recruitment and retention using limited resources and personnel. The long-range goal is to increase the number of PhD graduates from underrepresented groups by employing strategies that start at the 6–12th grade level. The …

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Understanding The Developments In The Business Perspective Of Cloud Computing: A Multidimensional Scaling Analysis, Harsh Parekh, Huai Tzu Cheng, Andrew Schwarz Jan 2023

Understanding The Developments In The Business Perspective Of Cloud Computing: A Multidimensional Scaling Analysis, Harsh Parekh, Huai Tzu Cheng, Andrew Schwarz

Faculty Publications

Research on cloud computing (CC) has gained a lot of momentum owing to its massive adoption. It has moved beyond the exploration of inherent capabilities to understand its disruptiveness and transformative value. In this vein, the authors conducted a comparative literature review of 101 articles to better understand the developments from previous reviews. This article serves as a replication study to evaluate the growth of the business perspective of CC. The authors identify 126 factors guiding the characteristics, adoption, governance, and business impact of the cloud. Further, they employ a rigorous analysis that situates our review at the intersection of …

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Quasistatic Evolution With Unstable Forces, Debdeep Bhattacharya, Robert P. Lipton Jan 2023

Quasistatic Evolution With Unstable Forces, Debdeep Bhattacharya, Robert P. Lipton

Faculty Publications

We consider load controlled quasistatic evolution. Well posedness results for the nonlocal continuum model related to peridynamics are established. We show local existence and uniqueness of quasistatic evolution for load paths originating at stable critical points. These points can be associated with local energy minima among the convex set of deformations belonging to the strength domain of the material. The evolution of the displacements, however, is not constrained to lie inside the strength domain of the material. The load-controlled evolution is shown to exhibit energy balance.

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Simulating Grain Shape Effects And Damage In Granular Media Using Peridem, Debdeep Bhattacharya, Robert P. Lipton Jan 2023

Simulating Grain Shape Effects And Damage In Granular Media Using Peridem, Debdeep Bhattacharya, Robert P. Lipton

Faculty Publications

We provide a numerical platform for the analysis of particle shape and topology effect on the macroscopic behavior of granular media. We work within a discrete element method (DEM) framework and apply a peridynamic model for deformable particles accounting for deformation and damage of individual particles. To accommodate arbitrary particle shapes including nonconvex ones as well as particle topology, an efficient method is developed to keep intraparticle peridynamic interaction within particle boundaries. Particle contact with the rigid boundary wall is computed analytically to improve accuracy. To speed up simulations with particles of different shapes and sizes the initial configuration is …

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Local Observer For Parameters And For State Variables Of Nonlinear Systems, Frederic Mazenc, Michael Malisoff Jan 2023

Local Observer For Parameters And For State Variables Of Nonlinear Systems, Frederic Mazenc, Michael Malisoff

Faculty Publications

We provide new observer designs to simultaneously identify parameters and states of systems whose nonlinearities have order two near the origin, which include cubic terms arising in the study of jump phenomena, process control, and bistable models of aerospace systems. This yields local exponential convergence of the state estimation error to zero, basin of attraction estimates, and fixed time parameter identification. We illustrate our result using Duffing's equation, whose cubic term puts it outside the scope of prior methods.

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Discrete-Time Trajectory-Based Stabilization Approach Using Interval Observer, Frederic Mazenc, Michael Malisoff, Jackson Knox Jan 2023

Discrete-Time Trajectory-Based Stabilization Approach Using Interval Observer, Frederic Mazenc, Michael Malisoff, Jackson Knox

Faculty Publications

We provide a discrete-time vector valued analog of recently developed continuous-time trajectory-based estimates. We use it to provide a discrete-time version of Halanay's inequality. We combine the results with interval observers to prove exponential stability properties for discrete-time linear systems with uncertainties whose arbitrarily long input delays are compensated for by reduction model controls, and a robust global exponential stability result for observers for discrete-time linear systems.

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Reference Governor Design In The Presence Of Uncertain Polynomial Constraints, Rick Schieni, Chengwei Zhao, Michael Malisoff, Laurent Burlion Jan 2023

Reference Governor Design In The Presence Of Uncertain Polynomial Constraints, Rick Schieni, Chengwei Zhao, Michael Malisoff, Laurent Burlion

Faculty Publications

Reference governors are add-on schemes that are used to modify trajectories to prevent controlled dynamical systems from violating input or state constraints, and so are playing an increasingly important role in aerospace, robotic, and other applications. Here we present a novel reference governor design for systems whose polynomial constraints depend on unknown bounded parameters. This is a significant departure from earlier treatments of reference governors, where the constraints were linear or known, because here we transfer the uncertainties into the constraints instead of having them in the closed loop dynamics, which greatly simplifies the task of determining future evolution of …

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Almost Fixed Time Observers For Parameters And For State Variables Of Nonlinear Systems, Frederic Mazenc, Michael Malisoff, Laurent Burlion Jan 2023

Almost Fixed Time Observers For Parameters And For State Variables Of Nonlinear Systems, Frederic Mazenc, Michael Malisoff, Laurent Burlion

Faculty Publications

We provide new finite-time and fast-converging observers for continuous-time nonlinear systems that contain unknown constant parameters and measurement delays. When the dynamics are affine in the unmeasured state, we obtain fixed time observers that identify unknown states and unknown model parameters. When the dynamics contain a nonlinearity that depends on the unmeasured state, we instead obtain asymptotic convergence of our observers, whose rate of convergence converges to infinity as the growth rate of this nonlinearity converges to zero, so in this case we call the observers almost fixed time observers. Our examples illustrate how our assumptions can be easily checked.

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Mathematical Models Of Topologically Protected Transport In Twisted Bilayer Graphene, Guillaume Bal, Paul Cazeaux, Daniel Massatt, Solomon Quinn Jan 2023

Mathematical Models Of Topologically Protected Transport In Twisted Bilayer Graphene, Guillaume Bal, Paul Cazeaux, Daniel Massatt, Solomon Quinn

Faculty Publications

Twisted bilayer graphene gives rise to large moir\'e patterns that form a triangular network upon mechanical relaxation. If gating is included, each triangular region has gapped electronic Dirac points that behave as bulk topological insulators with topological indices depending on valley index and the type of stacking. Since each triangle has two oppositely charged valleys, they remain topologically trivial. In this work, we address several questions related to the edge currents of this system by analysis and computation of continuum PDE models. First, we derive the bulk invariants corresponding to a single valley, and then apply a bulk-interface correspondence to …

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Uniqueness Of Entire Solutions To Quasilinear Equations Of P-Laplace Type, Nguyen Cong Phuc, Igor E. Verbitsky Jan 2023

Uniqueness Of Entire Solutions To Quasilinear Equations Of P-Laplace Type, Nguyen Cong Phuc, Igor E. Verbitsky

Faculty Publications

We prove the uniqueness property for a class of entire solutions to the equation (Formula presented) where σ is a nonnegative locally finite measure in Rn, absolutely continuous with respect to the p-capacity, and div A(x, ∇u) is the A-Laplace operator, under standard growth and monotonicity assumptions of order p (1 < p < ∞) on A(x, ξ) (x, ξ ∈ Rn); the model case A(x, ξ) = ξ|ξ|p−2 corresponds to the p-Laplace operator ∆p on Rn. Our main results establish uniqueness of solutions to a similar problem,(Formula presented) in the sub-natural growth case 0 < q < p − 1, where µ, σ are nonnegative locally finite measures in Rn, absolutely continuous with respect to the …

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An Upper Bound For The Circumference Of A 3-Connected Binary Matroid, Manoel Lemos, James Oxley Jan 2023

An Upper Bound For The Circumference Of A 3-Connected Binary Matroid, Manoel Lemos, James Oxley

Faculty Publications

Jim Geelen and Peter Nelson proved that, for a loopless connected binary ma-troid M with an odd circuit, if a largest odd circuit of M has k elements, then a largest circuit of M has at most 2k − 2 elements. The goal of this note is to show that, when M is 3-connected, either M has a spanning circuit, or a largest circuit of M has at most 2k − 4 elements. Moreover, the latter holds when M is regular of rank at least four.

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Generalizing Cographs To 2-Cographs, James Oxley, Jagdeep Singh Jan 2023

Generalizing Cographs To 2-Cographs, James Oxley, Jagdeep Singh

Faculty Publications

A graph in which every connected induced subgraph has a disconnected complement is called a cograph. Such graphs are precisely the graphs that do not have the 4-vertex path as an induced subgraph. We define a 2-cograph to be a graph in which the complement of every 2-connected induced subgraph is not 2-connected. We show that, like cographs, 2-cographs can be recursively defined and are closed under induced minors. We characterize the class of non-2-cographs for which every proper induced minor is a 2-cograph. We further find the finitely many members of this class whose complements are also induced-minor-minimal non-2-cographs.

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Seepage-Induced Pore Pressure Variations Beneath An Earthen Levee Measured With A Novel Seismic Tool, Daniel Locci-Lopez, Juan M. Lorenzo Jan 2023

Seepage-Induced Pore Pressure Variations Beneath An Earthen Levee Measured With A Novel Seismic Tool, Daniel Locci-Lopez, Juan M. Lorenzo

Faculty Publications

Shear-wave seismic reflection velocity-versus-depth models can complement our understanding of seepage pore pressure variations beneath earthen levees at locations between geotechnical sites. The seasonal variations of water level in the Mississippi River create pore pressure changes in the adjacent hydraulically connected aquifer on the protected side of artificial levees. Time-lapse shear-wave velocity analysis or repetition of seismic acquisition over an area is a non-invasive method that can detect seasonal pore pressure variations in shallow (< 40 m) aquifers. The seismic reflection patterns during the seasonal pore pressure variations of the river show a distinctive change in the velocity semblance analysis, which is translated as a change in the average stress carried by the grain-to-grain contact, or simply the effective pressure. The seismic data show a greater variation of up to +140/−40 m/s or +700/−150 kPa in the confined aquifer zone, compared with the leaky confined aquifer zone of up to +46/−48 m/s or +140/−80 kPa. These relative effective pressure characteristics allow us to distinguish between confined and leaky aquifers and can be an optional approach for pressure prediction in floodplains along levees without the need to drill borings in the area to measure piezometric data.

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Climate And Atlantic Sea-Level Recorded In Southwestern Spain From 6.3 To 5.2 Ma. Inferences On The Messinian Crisis In The Mediterranean, Jean Pierre Suc, Séverine Fauquette, Sophie Warny, Gonzalo Jiménez-Moreno, Damien Do Couto Jan 2023

Climate And Atlantic Sea-Level Recorded In Southwestern Spain From 6.3 To 5.2 Ma. Inferences On The Messinian Crisis In The Mediterranean, Jean Pierre Suc, Séverine Fauquette, Sophie Warny, Gonzalo Jiménez-Moreno, Damien Do Couto

Faculty Publications

The Mio-Pliocene succession of Andalusia on the Atlantic coast (Guadalquivir Basin) is known as one of the former stratotype candidate for the Andalusian Stage, proposed during the seventies as the last stage of the Miocene. Its type section is located in Carmona, east of Seville. Our investigation includes the drilling of three cored boreholes, which provide bio- and magnetic-stratigraphic data in complement to pre-existing industrial information, and a high-resolution palynological analysis (pollen grains, spores and dinoflagellate cysts). The pollen flora and its climatic quantification provide the mean to correlate the section to the oxygen isotope curve from the Montemayor-1 borehole, …

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The Lagrangian Numerical Relativity Code Sphincs_Bssn_V1.0, Stephan Rosswog, Francesco Torsello, Peter Diener Jan 2023

The Lagrangian Numerical Relativity Code Sphincs_Bssn_V1.0, Stephan Rosswog, Francesco Torsello, Peter Diener

Faculty Publications

We present version 1.0 of our Lagrangian numerical relativity code SPHINCS_BSSN. This code evolves the full set of Einstein equations, but contrary to other numerical relativity codes, it evolves the matter fluid via Lagrangian particles in the framework of a high-accuracy version of smooth particle hydrodynamics (SPH). The major new elements introduced here are: (i) a new method to map the stress–energy tensor (known at the particles) to the spacetime mesh, based on a local regression estimate; (ii) additional measures that ensure the robust evolution of a neutron star through its collapse to a black hole; and (iii) further refinements …

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Superfgd Prototype Time Resolution Studies, I. Alekseev, T. Arihara, V. Baranov, L. Bartoszek, L. Bernardi, A. Blondel, A. V. Boikov, M. Buizza-Avanzini, F. Cadoux, J. Capó, J. Cayo, J. Chakrani, P. S. Chong, A. Chvirova, M. Danilov, Y. I. Davydov, A. Dergacheva, N. Dokania, D. Douqa, O. Drapier, A. Eguchi, Y. Favre, D. Fedorova, S. Fedotov, Y. Fujii, F. Gastaldi, A. Gendotti, V. Glagolev, R. Guillaumat, K. Iwamoto, M. Jakkapu, C. Jesús-Valls, C. K. Jung Jan 2023

Superfgd Prototype Time Resolution Studies, I. Alekseev, T. Arihara, V. Baranov, L. Bartoszek, L. Bernardi, A. Blondel, A. V. Boikov, M. Buizza-Avanzini, F. Cadoux, J. Capó, J. Cayo, J. Chakrani, P. S. Chong, A. Chvirova, M. Danilov, Y. I. Davydov, A. Dergacheva, N. Dokania, D. Douqa, O. Drapier, A. Eguchi, Y. Favre, D. Fedorova, S. Fedotov, Y. Fujii, F. Gastaldi, A. Gendotti, V. Glagolev, R. Guillaumat, K. Iwamoto, M. Jakkapu, C. Jesús-Valls, C. K. Jung

Faculty Publications

The SuperFGD detector will be a novel and important upgrade to the ND280 near detector for both the T2K and Hyper-Kamiokande projects. The main goal of the ND280 upgrade is to reduce systematic uncertainties associated with neutrino flux and cross-section modeling for future studies of neutrino oscillations using the T2K and Hyper-Kamiokande experiments. The upgraded ND280 detector will be able to perform a full exclusive reconstruction of the final state from neutrino-nucleus interactions, including measurements of low momentum protons, pions and for the first time, event-by event measurements of neutron kinematics. Precisely understanding the time resolution is critical for the …

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Lsu General Catalog 2023-2024, Louisiana State University And Agricultural And Mechanical College Jan 2023

Lsu General Catalog 2023-2024, 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.

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Ab Initio Symmetry-Adapted Emulator For Studying Emergent Collectivity And Clustering In Nuclei, K. S. Becker, K. D. Launey, A. Ekström, T. Dytrych Jan 2023

Ab Initio Symmetry-Adapted Emulator For Studying Emergent Collectivity And Clustering In Nuclei, K. S. Becker, K. D. Launey, A. Ekström, T. Dytrych

Faculty Publications

We discuss emulators from the ab initio symmetry-adapted no-core shell-model framework for studying the formation of alpha clustering and collective properties without effective charges. We present a new type of an emulator, one that utilizes the eigenvector continuation technique but is based on the use of symplectic symmetry considerations. This is achieved by using physically relevant degrees of freedom, namely, the symmetry-adapted basis, which exploits the almost perfect symplectic symmetry in nuclei. Specifically, we study excitation energies, point-proton root-mean-square radii, along with electric quadrupole moments and transitions for 6Li and 12C. We show that the set of parameterizations …

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Effects Of Anisotropy And Disorder On The Superconducting Properties Of Niobium, Mehdi Zarea, Hikaru Ueki, J. A. Sauls Jan 2023

Effects Of Anisotropy And Disorder On The Superconducting Properties Of Niobium, Mehdi Zarea, Hikaru Ueki, J. A. Sauls

Faculty Publications

We report results for the superconducting transition temperature and anisotropic energy gap for pure niobium based on Eliashberg’s equations and electron and phonon band structures computed from density functional theory. The electronic band structure is used to construct the Fermi surface and calculate the Fermi velocity at each point on the Fermi surface. The phonon bands are in excellent agreement with inelastic neutron scattering data. The corresponding phonon density of states and electron–phonon coupling define the electron–phonon spectral function, α2F(p, p′; ω), and the corresponding electron–phonon pairing interaction, which is the basis for computing the superconducting properties. The …

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Non-Fermi Liquid Behavior In The Three-Dimensional Hubbard Model, Samuel Kellar, Ka Ming Tam, Juana Moreno Jan 2023

Non-Fermi Liquid Behavior In The Three-Dimensional Hubbard Model, Samuel Kellar, Ka Ming Tam, Juana Moreno

Faculty Publications

We present a numerical study on the non-Fermi liquid behavior of a three-dimensional strongly correlated system. The Hubbard model in a simple cubic lattice is simulated by the dynamical cluster approximation; in particular, the quasi-particle weight is calculated at finite dopings for a range of temperatures. By fitting the quasi-particle weight to the marginal Fermi liquid form at finite doping near the putative quantum critical point, we find evidence of a separatrix between Fermi liquid and non-Fermi liquid regions. Our results suggest that a marginal Fermi liquid and possibly a quantum critical point exist in the non-symmetry broken solution of …

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The Link Between Marine Thermal Discharges And Nemopilema Nomurai Blooms Around Nuclear Power Plants, Jiawei Wu, Jie Kong, Edward A. Laws, Xin Liu, Changyun Wang, Jixin Chen, Mianrun Chen, Qingzhen Yao, Yantao Wang, Yu Zhen, Chaolun Li, Bangqin Huang Jan 2023

The Link Between Marine Thermal Discharges And Nemopilema Nomurai Blooms Around Nuclear Power Plants, Jiawei Wu, Jie Kong, Edward A. Laws, Xin Liu, Changyun Wang, Jixin Chen, Mianrun Chen, Qingzhen Yao, Yantao Wang, Yu Zhen, Chaolun Li, Bangqin Huang

Faculty Publications

Recent research has shown that jellyfish blooms occur more frequently near nuclear power plants (NPPs), and a relationship between thermal discharges from the NPPs and the blooms has been hypothesized. There is, however, no direct evidence that links the thermal discharges with jellyfish blooms. In this study, we conducted 3 cruises (pre-bloom, bloom, and post-bloom) during July to September 2017 in the area surrounding the largest NPP in northern China. The water temperature near the cooling water outfall rose by 2 °C. Although we found no significant impact on phytoplankton abundance or community composition near the outfall, a broader analysis …

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The Dose-Response Effect Of Aerobic Exercise On Inflammation In Colon Cancer Survivors, Justin C. Brown, Stephanie L.E. Compton, Jeffrey A. Meyerhardt, Guillaume Spielmann, Shengping Yang Jan 2023

The Dose-Response Effect Of Aerobic Exercise On Inflammation In Colon Cancer Survivors, Justin C. Brown, Stephanie L.E. Compton, Jeffrey A. Meyerhardt, Guillaume Spielmann, Shengping Yang

Faculty Publications

Background: Physical activity after surgical resection for colon cancer is associated with significantly longer disease-free survival. Inflammation is hypothesized to mediate the association between physical activity and disease-free survival in colon cancer. Methods: In this exploratory analysis of a randomized dose-response trial, 39 colon cancer survivors who completed standard therapy were stratified by cancer stage and randomized in a 1:1:1 ratio to one of three treatment groups for 24 weeks of usual-care control, 150 min/wk of moderate-intensity aerobic exercise (low-dose), or 300 min/wk of moderate-intensity aerobic exercise (high-dose). Inflammation outcomes included high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL6), and soluble tumor …

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Acute Exercise Induces Distinct Quantitative And Phenotypical T Cell Profiles In Men With Prostate Cancer, Erik D. Hanson, Samy Sakkal, Lauren C. Bates-Fraser, Shadney Que, Eunhan Cho, Guillaume Spielmann, Elif Kadife, John A. Violet, Claudio L. Battaglini, Lee Stoner, David B. Bartlett, Glenn K. Mcconell, Alan Hayes Jan 2023

Acute Exercise Induces Distinct Quantitative And Phenotypical T Cell Profiles In Men With Prostate Cancer, Erik D. Hanson, Samy Sakkal, Lauren C. Bates-Fraser, Shadney Que, Eunhan Cho, Guillaume Spielmann, Elif Kadife, John A. Violet, Claudio L. Battaglini, Lee Stoner, David B. Bartlett, Glenn K. Mcconell, Alan Hayes

Faculty Publications

Background: Reduced testosterone levels can influence immune system function, particularly T cells. Exercise during cancer reduces treatment-related side effects and provide a stimulus to mobilize and redistribute immune cells. However, it is unclear how conventional and unconventional T cells (UTC) respond to acute exercise in prostate cancer survivors compared to healthy controls. Methods: Age-matched prostate cancer survivors on androgen deprivation therapy (ADT) and those without ADT (PCa) along with non-cancer controls (CON) completed ∼45 min of intermittent cycling with 3 min at 60% of peak power interspersed by 1.5 min of rest. Fresh, unstimulated immune cell populations and intracellular perforin …

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Parental Engagement And Implementation Fidelity In A Mhealth Motor Skills Intervention For Young Children, Amanda E. Staiano, Sanjoy Saha, Robbie A. Beyl, Chelsea L. Kracht, Robert L. Newton, E. Kipling Webster Jan 2023

Parental Engagement And Implementation Fidelity In A Mhealth Motor Skills Intervention For Young Children, Amanda E. Staiano, Sanjoy Saha, Robbie A. Beyl, Chelsea L. Kracht, Robert L. Newton, E. Kipling Webster

Population and Public Health Science Faculty Publications

Introduction: Mobile apps (i.e. mHealth) provide unprecedented opportunity for widespread dissemination of health behavior programs. However, for programs directed towards young children, parental engagement may explain differing results of mHealth programs. Within the context of an app-based fundamental motor skill (FMS) intervention that improved children’s motor skills (PLAY), this paper examines parents’ fidelity to the intervention and the extent to which fidelity was related to children’s motor skill improvements. Methods: In the PLAY trial, 72 children aged 3–5 years were randomized for their parents to access a Motor Skills app or Free Play app for a 12-week intervention. The Motor …

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Validation Of Remote Assessment Of Preschool Children's Anthropometrics And Motor Skills, Alyssa M. Button, E. Kipling Webster, Chelsea L. Kracht, Chelsea Hendrick, Anthony Okely, Kar Hau Chong, Penny Cross, Amanda E. Staiano Jan 2023

Validation Of Remote Assessment Of Preschool Children's Anthropometrics And Motor Skills, Alyssa M. Button, E. Kipling Webster, Chelsea L. Kracht, Chelsea Hendrick, Anthony Okely, Kar Hau Chong, Penny Cross, Amanda E. Staiano

Population and Public Health Science Faculty Publications

Introduction: Remotely delivered treatment and research procedures were rapidly adopted in response to the COVID-19 pandemic. However, it is unclear if these measures are valid. The purpose of this study was to compare the validity of anthropometry and motor skill proficiency measurements collected in a remote-setting to in-person setting among a sample of children ages 3–4 years. Methods: Child anthropometry and motor skill performance were measured in-person by trained assessors and by parents at home with remote supervision via videoconference by trained assessors. The following measures from the National Institutes of Health Toolbox were collected: anthropometry (height and weight), manual …

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Phylogenomics Of Trans-Andean Tetras Of The Genus Hyphessobrycon Durbin 1908 (Stethaprioninae: Characidae) And Colonization Patterns Of Middle America, Diego J. Elías, Caleb D. Mcmahan, Fernando Alda, Carlos García-Alzate, Pamela B. Hart, Prosanta Chakrabarty Jan 2023

Phylogenomics Of Trans-Andean Tetras Of The Genus Hyphessobrycon Durbin 1908 (Stethaprioninae: Characidae) And Colonization Patterns Of Middle America, Diego J. Elías, Caleb D. Mcmahan, Fernando Alda, Carlos García-Alzate, Pamela B. Hart, Prosanta Chakrabarty

Faculty Publications

Hyphessobrycon is one of the most species rich and widely distributed genera in the family Characidae, with more than 160 species ranging from Veracruz, Mexico to Mar Chiquita Lagoon in Buenos Aires, Argentina. The majority of Hyphessobrycon diversity shows a cis- Andean distribution; only nine species are trans-Andean including H. compressus (Meek 1908). It is well established that Hyphessobrycon is not monophyletic but it has been suggested that natural groups can be identified within the larger Hyphessobrycon species group. In this study, we tested the monophyly of trans-Andean species of Hyphessobrycon and investigated the placement of H. compressus. We inferred …

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A Finite Element Method For A Two-Dimensional Pucci Equation, Susanne C. Brenner, Li Yeng Sung, Zhiyu Tan Jan 2023

A Finite Element Method For A Two-Dimensional Pucci Equation, Susanne C. Brenner, Li Yeng Sung, Zhiyu Tan

Faculty Publications

A nonlinear least-squares finite element method for strong solutions of the Dirichlet boundary value problem of a two-dimensional Pucci equation on convex polygonal domains is investigated in this paper. We obtain a priori and a posteriori error estimates and present corroborating numerical results, where the discrete nonsmooth and nonlinear optimization problems are solved by an active set method and an alternating direction method with multipliers.

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An Interior Maximum Norm Error Estimate For The Symmetric Interior Penalty Method On Planar Polygonal Domains, Susanne C. Brenner, Li Yeng Sung Jan 2023

An Interior Maximum Norm Error Estimate For The Symmetric Interior Penalty Method On Planar Polygonal Domains, Susanne C. Brenner, Li Yeng Sung

Faculty Publications

We establish an interior maximum norm error estimate for the symmetric interior penalty method on planar polygonal domains.

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A Geometric Trapping Approach To Global Regularity For 2d Navier-Stokes On Manifolds, Aynur Bulut, Manh Khang Huynh Jan 2023

A Geometric Trapping Approach To Global Regularity For 2d Navier-Stokes On Manifolds, Aynur Bulut, Manh Khang Huynh

Faculty Publications

In this paper, we use frequency decomposition techniques to give a direct proof of global existence and regularity for the Navier-Stokes equations on two-dimensional Riemannian manifolds without boundary. Our techniques are inspired by an approach of Mattingly and Sinai [15] which was developed in the context of periodic boundary conditions on a flat background, and which is based on a maximum principle for Fourier coefficients. The extension to general manifolds requires several new ideas, connected to the less favorable spectral localization properties in our setting. Our arguments make use of frequency projection operators, multilinear estimates that originated in the study …

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Right-Angled Coxeter Groups With Non-Planar Boundary, Pallavi Dani, Matthew Haulmark, Genevieve Walsh Jan 2023

Right-Angled Coxeter Groups With Non-Planar Boundary, Pallavi Dani, Matthew Haulmark, Genevieve Walsh

Faculty Publications

We investigate the planarity of the boundaries of right-angled Coxeter groups. We show that non-planarity of the defining graph does not necessarily imply non-planarity of every boundary of the associated right-angled Coxeter group, although it does in many cases. Our techniques yield a characterization of the triangle-free defining graphs such that the associated right-angled Coxeter group has boundary a Menger curve.

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