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Articles 32281 - 32310 of 302639

Full-Text Articles in Physical Sciences and Mathematics

Stabilizing Controlled Systems In The Presence Of Time-Delays, Isaac Becker Pardo Apr 2022

Stabilizing Controlled Systems In The Presence Of Time-Delays, Isaac Becker Pardo

Theses and Dissertations

A dynamical system's state evolves over time, and when the system stays near a particular state this state is known as a stable state of the system. Through control methods, dynamical systems can be manipulated such that virtually any state can be made stable. Although most real systems evolve continuously in time the application of digital control methods to these systems is inherently discrete. States are sampled (with sensors) and fed back into the system in discrete-time to determine the input needed to control the continuous system. Additionally, dynamical systems often experience time delays. Some examples of time delays are …


Fock And Hardy Spaces: Clifford Appell Case, Daniel Alpay, Kamal Diki, Irene Sabadini Apr 2022

Fock And Hardy Spaces: Clifford Appell Case, Daniel Alpay, Kamal Diki, Irene Sabadini

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this paper, we study a specific system of Clifford–Appell polynomials and, in particular, their product. Moreover, we introduce a new family of quaternionic reproducing kernel Hilbert spaces in the framework of Fueter regular functions. The construction is based on a general idea which allows us to obtain various function spaces by specifying a suitable sequence of real numbers. We focus on the Fock and Hardy cases in this setting, and we study the action of the Fueter mapping and its range.


Synthesis Of Molecularly Imprinted Polymer For The Detection Of Perfluorooctanoic Acid, Yuqi Wang, Hannah Rhodes Apr 2022

Synthesis Of Molecularly Imprinted Polymer For The Detection Of Perfluorooctanoic Acid, Yuqi Wang, Hannah Rhodes

Liberty University Research Week

Undergraduate

Basic


Inhibiting Nitroso Related Methylation Of Guanine Using Dietary Supplements And Flavonoids, Hannah Klose, Madeline Mccoy, Mary Hall Apr 2022

Inhibiting Nitroso Related Methylation Of Guanine Using Dietary Supplements And Flavonoids, Hannah Klose, Madeline Mccoy, Mary Hall

Liberty University Research Week

Undergraduate

Basic


High-Performance Liquid Chromatography Analysis Of Common Adulterants, Madison Landreth, Elijah Deyoung, Jedidiah Black, Lynza Osorio Apr 2022

High-Performance Liquid Chromatography Analysis Of Common Adulterants, Madison Landreth, Elijah Deyoung, Jedidiah Black, Lynza Osorio

Liberty University Research Week

Undergraduate

Basic


Detection Of 5-Fluoro-2-Oxindole And Products By Hplc After Reaction With Human Liver Enzymes, Kalie Nuss, Emma Mohler Apr 2022

Detection Of 5-Fluoro-2-Oxindole And Products By Hplc After Reaction With Human Liver Enzymes, Kalie Nuss, Emma Mohler

Liberty University Research Week

Undergraduate

Basic


The Effect Of Coca-Cola™ On Fresh And Latent Blood Stains, Brittany Johnson, Bethany Smith, Katie Steigerwald, Rachel Eberle Apr 2022

The Effect Of Coca-Cola™ On Fresh And Latent Blood Stains, Brittany Johnson, Bethany Smith, Katie Steigerwald, Rachel Eberle

Liberty University Research Week

Graduate

Basic


Synthesis And Characterization Of 5,6-Fused Ring Pyridazines, William Hobbs, Joshua Bird, Stephen Carter Apr 2022

Synthesis And Characterization Of 5,6-Fused Ring Pyridazines, William Hobbs, Joshua Bird, Stephen Carter

Liberty University Research Week

Undergraduate

Basic


Utilization Of Solid-State Catalysis For Screening Of Peroxidase Library, Zachariah Hutcheon, Alexa Deckert Apr 2022

Utilization Of Solid-State Catalysis For Screening Of Peroxidase Library, Zachariah Hutcheon, Alexa Deckert

Liberty University Research Week

Undergraduate

Basic


Synthesis Of Re(Co)3[1,2-C5h3(Coc4h3s)2], Chloe Vernon, Ryan Renfro, Wilmar Janusz Apr 2022

Synthesis Of Re(Co)3[1,2-C5h3(Coc4h3s)2], Chloe Vernon, Ryan Renfro, Wilmar Janusz

Liberty University Research Week

Undergraduate

Basic


Halfway: The Legacy Of Civilian Conservation Corps Company #704, Maxibillion Thompson Apr 2022

Halfway: The Legacy Of Civilian Conservation Corps Company #704, Maxibillion Thompson

Student Academic Conference

Civilian Conservation Corps Company #704 began operations in 1933 approximately 10 miles southeast of Ely, MN, based at the site known as Halfway Camp F-1. This presentation explores some of the legacy they left in the region in the form of ecological projects and recreational structures, as well as the few remaining signs of their former camp on the shores of Birch Lake.


Limits Of Detection Of Mycotoxins By Laminar Flow Strips: A Review, Xinyi Zhao, Hugh Byrne, Christine M. O’Connor, James Curtin, Furong Tian Apr 2022

Limits Of Detection Of Mycotoxins By Laminar Flow Strips: A Review, Xinyi Zhao, Hugh Byrne, Christine M. O’Connor, James Curtin, Furong Tian

Articles

Mycotoxins are secondary metabolic products of fungi. They are poisonous, carcinogenic, and mutagenic in nature and pose a serious health threat to both humans and animals, causing severe illnesses and even death. Rapid, simple and low-cost methods of detection of mycotoxins are of immense importance and in great demand in the food and beverage industry, as well as in agriculture and environmental monitoring, and, for this purpose, lateral flow immunochromatographic strips (ICSTs) have been widely used in food safety and environmental monitoring. The literature to date describing the development of ICSTs for the detection of different types of mycotoxins using …


Peptidomics Analysis Reveals Changes In Small Urinary Peptides In Patients With Interstitial Cystitis/Bladder Pain Syndrome, Md Shadman Ridwan Abid, Haowen Qiu, Bridget A. Tripp, Aline De Lima Leite, Heidi Roth, Jiri Adamec, Robert Powers, James W. Checco Apr 2022

Peptidomics Analysis Reveals Changes In Small Urinary Peptides In Patients With Interstitial Cystitis/Bladder Pain Syndrome, Md Shadman Ridwan Abid, Haowen Qiu, Bridget A. Tripp, Aline De Lima Leite, Heidi Roth, Jiri Adamec, Robert Powers, James W. Checco

UNL Student Research Days Posters, Graduate

Interstitial cystitis or bladder pain syndrome (IC/BPS) is a chronic and debilitating pain disorder of the bladder and urinary tract with poorly understood etiology. Symptomatic criteria to aid in the diagnosis of IC/BPS includes bladder pain, an increase in urinary urgency or Hunner’s ulcers on the bladder wall.

Our study revealed differences in the profiles of small urinary peptides for IC/BPS patients compared to age-matched controls which is consistent with increased protease activity in IC/BPS. Our study also enabled the direct measurement of APF peptide abundance in IC/BPS and control urine. Our results indicate that the full-length APF peptide was …


Comparing Satellite Vs Marine Potential Fields Data Over The Bathymetrists Seamounts, Alexa Fernandez, Irina Filina Apr 2022

Comparing Satellite Vs Marine Potential Fields Data Over The Bathymetrists Seamounts, Alexa Fernandez, Irina Filina

UNL Student Research Days Posters, Graduate

The Bathymetrists Seamounts (BSM) are located north of the Sierra Leone Rise (SLR) in the mid-Atlantic Ocean. The seamounts reside on oceanic crust that is 105 to 45 million years old. However, dredging over the Bathymetrists Seamounts dated rocks at ~40 Myr. The general trend of the seamounts contradicts the eastward motion of the African tectonic plate. The origin and tectonic history of the Bathymetrists Seamounts remains debated in literature. Potential fields (gravity and magnetic) data can provide important insight into the formation and evolution of the seamounts. The purpose of this study is to compare available gravity and magnetic …


Asymmetric Synthesis Of 𝜸-Borylated Amines Via Rhodium-Catalyzed Hydroboration Of Allylamine Derivatives, Rukshani Wickrama Arachchi, Shekhar Kc, Arun Suneja, James Takacs Apr 2022

Asymmetric Synthesis Of 𝜸-Borylated Amines Via Rhodium-Catalyzed Hydroboration Of Allylamine Derivatives, Rukshani Wickrama Arachchi, Shekhar Kc, Arun Suneja, James Takacs

UNL Student Research Days Posters, Graduate

The Takacs group has explored different dimensions of Catalytic Asymmetric Hydroboration (CAHB) reaction mainly focusing on variety of amide, oxime ether and phosphonate directing groups. Inspired by the results obtained with BINOL- and TADDOL- derived chiral catalysts along with pinacolborane, we explored the potential of acyclic N-acyl allylamines as substrates for direct-hydroboration to prepare chiral amine derivatives bearing g-boronic ester functionality, yields up to 90% with 98:2 enantioselectivity. The major enantiomer obtained is independent of starting alkene geometry, revealing that rhodium-catalyzed cis/trans-alkene isomerization occurs prior to hydroboration. In this poster, we will discuss the generation of active catalysts …


The Gelfand Problem For The Infinity Laplacian, Fernando Charro, Byungjae Son, Peiyong Wang Apr 2022

The Gelfand Problem For The Infinity Laplacian, Fernando Charro, Byungjae Son, Peiyong Wang

Mathematics Faculty Research Publications

We study the asymptotic behavior as p → ∞ of the Gelfand problem

−Δpu = λeu in Ω ⊂ Rn, u = 0 on ∂Ω.

Under an appropriate rescaling on u and λ, we prove uniform convergence of solutions of the Gelfand problem to solutions of

min{|∇u|−Λeu, −Δu} = 0 in Ω, u = 0 on ∂Ω.

We discuss existence, non-existence, and multiplicity of solutions of the limit problem in terms of Λ.


Molecular Characterization Of Rickettsial Agents In Ticks (Acari: Ixodidae) From Sri Lanka, Gregory A. Dasch, Marina Eremeeva, Maria L. Zambrano, Ranjan Premaratna, S. A. M. Kularatne Apr 2022

Molecular Characterization Of Rickettsial Agents In Ticks (Acari: Ixodidae) From Sri Lanka, Gregory A. Dasch, Marina Eremeeva, Maria L. Zambrano, Ranjan Premaratna, S. A. M. Kularatne

Department of Biostatistics, Epidemiology, and Environmental Health Sciences Faculty Publications

Because the majority of spotted fever group rickettsiae are transmitted to humans by tick bites, it is important to understand which ticks might play a role in transmission of rickettsial pathogens in Sri Lanka. The purpose of our study was to conduct molecular surveillance of 847 ticks collected in different locations in central Sri Lanka to determine which were infected with Rickettsia and Anaplasmataceae. Molecular methods were used to identify the ticks and the agents detected. Most ticks (Amblyomma, Haemaphysalis, and Rhipicephalus) were collected by flagging, and lower number was collected from dogs, cattle, pigs, a …


White Noise Space Analysis And Multiplicative Change Of Measures, Daniel Alpay, Palle Jorgensen, Motke Porat Apr 2022

White Noise Space Analysis And Multiplicative Change Of Measures, Daniel Alpay, Palle Jorgensen, Motke Porat

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this paper, we display a family of Gaussian processes, with explicit formulas and transforms. This is presented with the use of duality tools in such a way that the corresponding path-space measures are mutually singular. We make use of a corresponding family of representations of the canonical commutation relations (CCR) in an infinite number of degrees of freedom. A key feature of our construction is explicit formulas for associated transforms; these are infinite-dimensional analogs of Fourier transforms. Our framework is that of Gaussian Hilbert spaces, reproducing kernel Hilbert spaces and Fock spaces. The latter forms the setting for our …


Theranostic Copolymers Neutralize Reactive Oxygen Species And Lipid Peroxidation Products For The Combined Treatment Of Traumatic Brain Injury, Aaron Priester, Richard Waters, Ashleigh Abbott, Krista Hilmas, Klaus Woelk, Hunter A. Miller, Aria W. Tarudji, Connor C. Gee, Brandon Mcdonald, Forrest M. Kievit, Anthony J. Convertine Apr 2022

Theranostic Copolymers Neutralize Reactive Oxygen Species And Lipid Peroxidation Products For The Combined Treatment Of Traumatic Brain Injury, Aaron Priester, Richard Waters, Ashleigh Abbott, Krista Hilmas, Klaus Woelk, Hunter A. Miller, Aria W. Tarudji, Connor C. Gee, Brandon Mcdonald, Forrest M. Kievit, Anthony J. Convertine

Chemistry Faculty Research & Creative Works

Traumatic brain injury (TBI) results in the generation of reactive oxygen species (ROS) and lipid peroxidation product (LPOx), including acrolein and 4-hydroxynonenal (4HNE). The presence of these biochemical derangements results in neurodegeneration during the secondary phase of the injury. The ability to rapidly neutralize multiple species could significantly improve outcomes for TBI patients. However, the difficulty in creating therapies that target multiple biochemical derangements simultaneously has greatly limited therapeutic efficacy. Therefore, our goal was to design a material that could rapidly bind and neutralize both ROS and LPOx following TBI. To do this, a series of thiol-functionalized biocompatible copolymers based …


One-Dimensional Array Of Optical Dark Spot Traps From Nested Gaussian Laser Beams For Quantum Computing, Katharina Gillen-Christandl, Travis Daniel Frazer Apr 2022

One-Dimensional Array Of Optical Dark Spot Traps From Nested Gaussian Laser Beams For Quantum Computing, Katharina Gillen-Christandl, Travis Daniel Frazer

Physics

Quantum computing is rapidly becoming a practical technology, driven by new and advanced quantum systems, each with its own advantages and disadvantages. For neutral atoms as a host system, the natural advantage of long lifetimes is limited by decoherence mechanisms like light scattering. In this work, we computationally investigate a blue-detuned one-dimensional optical dipole trap array to reduce light scattering by holding atoms in minimum light intensity regions. The array consists of two counter-propagating Gaussian beams of differing widths, such that light walls from the larger beam radially confine the standing wave generating the dipole traps. We find this system …


Eigenfunction Restriction Estimates For Curves With Nonvanishing Geodesic Curvatures In Compact Riemannian Surfaces With Nonpositive Sectional Curvatures, Chamsol Park Apr 2022

Eigenfunction Restriction Estimates For Curves With Nonvanishing Geodesic Curvatures In Compact Riemannian Surfaces With Nonpositive Sectional Curvatures, Chamsol Park

Mathematics & Statistics ETDs

For 2 ≤ p < 4, we study the Lp norms of restrictions of eigenfunctions of the Laplace-Beltrami operator on smooth compact 2-dimensional Riemannian manifolds. Burq, G\´erard, and Tzvetkov [12], and Hu [21] found eigenfunction restriction estimates for a curve with nonvanishing geodesic curvatures. We will explain how the proof of the known estimates helps us to consider the case where the given smooth compact Riemannian manifold has nonpositive sectional curvatures. For p = 4, we will also obtain a logarithmic analogous estimate, by using arguments in Xi and Zhang [37], Sogge [33], and Bourgain [10]. At the end of this dissertation, we will talk about a future work, which is a follow up study for higher dimensional analogues of the above curve cases.


Machine Learning Based Medical Image Deepfake Detection: A Comparative Study, Siddharth Solaiyappan, Yuxin Wen Apr 2022

Machine Learning Based Medical Image Deepfake Detection: A Comparative Study, Siddharth Solaiyappan, Yuxin Wen

Engineering Faculty Articles and Research

Deep generative networks in recent years have reinforced the need for caution while consuming various modalities of digital information. One avenue of deepfake creation is aligned with injection and removal of tumors from medical scans. Failure to detect medical deepfakes can lead to large setbacks on hospital resources or even loss of life. This paper attempts to address the detection of such attacks with a structured case study. Specifically, we evaluate eight different machine learning algorithms, which include three conventional machine learning methods (Support Vector Machine, Random Forest, Decision Tree) and five deep learning models (DenseNet121, DenseNet201, ResNet50, ResNet101, VGG19) …


Silver Bow Creek/Butte Area Npl Site Butte Priority Soils Operable Unit, Pioneer Technical Services, Inc. Apr 2022

Silver Bow Creek/Butte Area Npl Site Butte Priority Soils Operable Unit, Pioneer Technical Services, Inc.

Silver Bow Creek/Butte Area Superfund Site

No abstract provided.


A Nematode Community-Based Integrated Productivity Efficiency (Ipe) Model That Identifies Sustainable Soil Health Outcomes: A Case Of Compost Application In Carrot Production, A. Habteweld, A. Kravchencko, Parwinder Grewal, H. Melakeberhan Apr 2022

A Nematode Community-Based Integrated Productivity Efficiency (Ipe) Model That Identifies Sustainable Soil Health Outcomes: A Case Of Compost Application In Carrot Production, A. Habteweld, A. Kravchencko, Parwinder Grewal, H. Melakeberhan

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Percent soil organic matter (SOM), pH and crop yield are among the biophysicochemical process-driven soil health indicators (SHIs). However, identifying sustainable soil health conditions using these SHIs is limited due to the lack of Integrated Productivity Efficiency (IPE) models. We define IPE as a concept that identifies best-to-worst-case soil health outcomes by assessing the effect of agronomic practices on weighted abundance of functional guilds (WAFG) of beneficial soil organisms and SHIs simultaneously. Expressing WAFG of all beneficial nematodes (x-axis) and SHIs (y-axis) as a percent of untreated control and regression of x and y reveals four quadrants describing worst-to-best-case outcomes …


Practical Considerations And Applications For Autonomous Robot Swarms, Rory Alan Hector Apr 2022

Practical Considerations And Applications For Autonomous Robot Swarms, Rory Alan Hector

LSU Doctoral Dissertations

In recent years, the study of autonomous entities such as unmanned vehicles has begun to revolutionize both military and civilian devices. One important research focus of autonomous entities has been coordination problems for autonomous robot swarms. Traditionally, robot models are used for algorithms that account for the minimum specifications needed to operate the swarm. However, these theoretical models also gloss over important practical details. Some of these details, such as time, have been considered before (as epochs of execution). In this dissertation, we examine these details in the context of several problems and introduce new performance measures to capture practical …


Computationally Assisted Nmr Crystallography: A Path To Unusually High-Resolution Crystal Structures, Luther Wang Apr 2022

Computationally Assisted Nmr Crystallography: A Path To Unusually High-Resolution Crystal Structures, Luther Wang

Theses and Dissertations

Crystallography has traditionally been studied by diffraction methods involving X ray or neutron radiation. These methods have some limitations, from requiring the substance under study to form single crystals to the limited ability of X rays to locate hydrogen atoms. While neutron radiation can characterize hydrogens, it is expensive, not readily available and has its own particular limits on resolution. It this dissertation, it is demonstrated that NMR is extraordinarily sensitive to atomic positions, with variations of mere tens of femtometers creating statistically distinguishable chemical shift changes. To date, no other means of measurement can detect structural changes at this …


Gas Phase Structure Characterization Of Host-Guest Systems Using Ion Mobility Spectrometry, Jamir Shrestha Apr 2022

Gas Phase Structure Characterization Of Host-Guest Systems Using Ion Mobility Spectrometry, Jamir Shrestha

Theses and Dissertations

This dissertation focuses on the investigation of gas-phase characteristics of cucurbituril host-guest systems using ion mobility spectrometry (IMS) and related techniques. Collision cross-sections (CCS) of alkylammonium complexes of cucurbit[n]uril (CB[n]) are measured to understand the allosteric interactions that induce conformational changes in the complex in the presence of metal cations on one of the portals of the cucurbit[6]uril (CB[6]) host. Cationic species on one CB[6] rim sterically force longer linear alkylammonium guests out of the cucurbituril cavity during complex formation. Similarly, rigid cucurbituril-metal complexes were studied using IMS to demonstrate the effect of long-range ion-neutral interactions on the gas phase …


Life And Death In A Dynamic Environment: Invasive Trout, Floods, And Intraspecific Drivers Of Translocated Populations, Brian D. Healy, Phaedra Budy, Mary M. Conner, Emily C. Omana Smith Apr 2022

Life And Death In A Dynamic Environment: Invasive Trout, Floods, And Intraspecific Drivers Of Translocated Populations, Brian D. Healy, Phaedra Budy, Mary M. Conner, Emily C. Omana Smith

Wildland Resources Faculty Publications

Understanding the relative strengths of intrinsic and extrinsic factors regulating populations is a long-standing focus of ecology and critical to advancing conservation programs for imperiled species. Conservation could benefit from an increased understanding of factors influencing vital rates (somatic growth, recruitment, survival) in small, translocated populations, which is lacking owing to difficulties in long-term monitoring of rare species. Translocations, here defined as the transfer of wild-captured individuals from source populations to new habitats, are widely used for species conservation, but outcomes are often minimally monitored, and translocations that are monitored often fail. To improve our understanding of how translocated populations …


Beam-Spin Asymmetry Σ For Σ- Hyperon Photoproduction Off The Neutron, N. Zachariou, E. Munevar, B. L. Berman, P. Bydžovský, A. Cieplý, G. Feldman, Y. Ilieva, P. Nadel-Turonski, D. Skoupil, A. V. Sarantsev, D. P. Watts, M. J. Amaryan, G. Angelini, W. R. Armstrong, H. Atac, H. Avakian, L. Barion, M. Bashkanov, M. Battaglieri, Steffen Strauch, Et. Al. Apr 2022

Beam-Spin Asymmetry Σ For Σ- Hyperon Photoproduction Off The Neutron, N. Zachariou, E. Munevar, B. L. Berman, P. Bydžovský, A. Cieplý, G. Feldman, Y. Ilieva, P. Nadel-Turonski, D. Skoupil, A. V. Sarantsev, D. P. Watts, M. J. Amaryan, G. Angelini, W. R. Armstrong, H. Atac, H. Avakian, L. Barion, M. Bashkanov, M. Battaglieri, Steffen Strauch, Et. Al.

Faculty Publications

We report a new measurement of the beam-spin asymmetry, Σ, for the γn → K + Σ− reaction using quasi-free neutrons in a liquid-deuterium target. The new dataset includes data at previously unmeasured photon energy and angular ranges, thereby providing new constraints on partial wave analyses used to extract properties of the excited nucleon states. The experimental data were obtained using the CEBAF Large Acceptance Spectrometer (CLAS), housed in Hall B of the Thomas Jefferson National Accelerator Facility (JLab). The CLAS detector measured reaction products from a liquid-deuterium target produced by an energy-tagged, linearly polarised photon beam with energies in …


A New Perspective On A Polynomial Time Knot Polynomial, Robert John Quarles Apr 2022

A New Perspective On A Polynomial Time Knot Polynomial, Robert John Quarles

LSU Doctoral Dissertations

In this work we consider the Z1(K) polynomial time knot polynomial defined and
described by Dror Bar-Natan and Roland van der Veen in their 2018 paper ”A polynomial time knot polynomial”. We first look at some of the basic properties of Z1(K), and develop an invariant of diagrams Ψm(D) related to this polynomial. We use this invariant as a model to prove how Z1(K) acts under the connected sum operation. We then discuss the effect of mirroring the knot on Z1(K), and described a geometric interpretation of some of the building blocks of the invariant. We then use these to …