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2022

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Articles 18151 - 18180 of 18295

Full-Text Articles in Physical Sciences and Mathematics

Population And Migratory Ecology Of Canada Warblers (Cardellina Canadensis) In The Central Appalachian Mountains, West Virginia, Usa, Stephanie H. Augustine Jan 2022

Population And Migratory Ecology Of Canada Warblers (Cardellina Canadensis) In The Central Appalachian Mountains, West Virginia, Usa, Stephanie H. Augustine

Graduate Theses, Dissertations, and Problem Reports

Nearctic-Neotropical migrant birds experience a wide range of environmental conditions throughout their annual cycle; thus, it is particularly challenging to evaluate the spatial factors that may influence population growth. The Canada Warbler (Cardellina canadensis) faces substantial range-wide population declines, but little study has been conducted regarding elements occurring across the entire year that drive demographic rates. The aims of this research are (1) determine the relationship between Canada Warbler population demographic rates and environmental conditions along an elevation gradient in the central Appalachian Mountains and (2) ascertain the nonbreeding season location and migratory routes used by the central …


Exploring Cyberterrorism, Topic Models And Social Networks Of Jihadists Dark Web Forums: A Computational Social Science Approach, Vivian Fiona Guetler Jan 2022

Exploring Cyberterrorism, Topic Models And Social Networks Of Jihadists Dark Web Forums: A Computational Social Science Approach, Vivian Fiona Guetler

Graduate Theses, Dissertations, and Problem Reports

This three-article dissertation focuses on cyber-related topics on terrorist groups, specifically Jihadists’ use of technology, the application of natural language processing, and social networks in analyzing text data derived from terrorists' Dark Web forums. The first article explores cybercrime and cyberterrorism. As technology progresses, it facilitates new forms of behavior, including tech-related crimes known as cybercrime and cyberterrorism. In this article, I provide an analysis of the problems of cybercrime and cyberterrorism within the field of criminology by reviewing existing literature focusing on (a) the issues in defining terrorism, cybercrime, and cyberterrorism, (b) ways that cybercriminals commit a crime in …


An Analysis On Adversarial Machine Learning: Methods And Applications, Ali Dabouei Jan 2022

An Analysis On Adversarial Machine Learning: Methods And Applications, Ali Dabouei

Graduate Theses, Dissertations, and Problem Reports

Deep learning has witnessed astonishing advancement in the last decade and revolutionized many fields ranging from computer vision to natural language processing. A prominent field of research that enabled such achievements is adversarial learning, investigating the behavior and functionality of a learning model in presence of an adversary. Adversarial learning consists of two major trends. The first trend analyzes the susceptibility of machine learning models to manipulation in the decision-making process and aims to improve the robustness to such manipulations. The second trend exploits adversarial games between components of the model to enhance the learning process. This dissertation aims to …


Bayesian Methods For Multi-Messenger Analysis Of Supermassive Black Hole Binaries: Pulsars And Quasars And Gravitational Waves, Oh My!, Caitlin A. Witt Jan 2022

Bayesian Methods For Multi-Messenger Analysis Of Supermassive Black Hole Binaries: Pulsars And Quasars And Gravitational Waves, Oh My!, Caitlin A. Witt

Graduate Theses, Dissertations, and Problem Reports

Supermassive black hole binaries (SMBHBs) can lurk, often unseen, in the centers of post-merger galaxies, and pulsar timing arrays (PTAs) are rapidly approaching the sensitivities required to detect nanohertz gravitational waves (GWs) from these giant pairs. Independently, numerous electromagnetic surveys are seeking evidence of these dynamic duos’ effects on their host galaxies by searching for periodicities in time-domain observations. Combining these two methods to use multi-messenger techniques allows us to learn more about these binaries than using one messenger alone. In this thesis, we have created Bayesian methods to search for SMBHBs using electromagnetic observations of quasars and through GW …


Learning Representations For Human Identification, Sinan Sabri Jan 2022

Learning Representations For Human Identification, Sinan Sabri

Graduate Theses, Dissertations, and Problem Reports

Long-duration visual tracking of people requires the ability to link track snippets (a.k.a. tracklets) based on the identity of people. In lack of the availability of motion priors or hard biometrics (e.g., face, fingerprint, or iris), the common practice is to leverage soft biometrics for matching tracklets corresponding to the same person in different sightings. A common choice is to use the whole-body visual appearance of the person, as determined by the clothing, which is assumed to not change during tracking. The problem is challenging because distinct images of the same person may look very different, since no restrictions are …


Hot-Carrier Dynamics And Transport Mechanisms In Inas/Alassb Multiple Quantum Wells, Herath Pathiranage Janaka Chathuranga Piyathilaka Jan 2022

Hot-Carrier Dynamics And Transport Mechanisms In Inas/Alassb Multiple Quantum Wells, Herath Pathiranage Janaka Chathuranga Piyathilaka

Graduate Theses, Dissertations, and Problem Reports

Semiconductor photovoltaics convert light into electricity through the extraction of photo-excited charge carriers. Among the most important parameters for a photovoltaic cell are good optical absorption in the desired region of the electromagnetic spectrum, and sufficient excited-state lifetimes and mobilities of the photocarriers to allow for charge separation and extraction before recombination. For solar cell applications there are significant challenges to overcome to improve the efficiency of the light-to-electricity conversion. The cells are most commonly made of silicon, which has a nearly perfect bandgap for absorbing the most solar radiation, an indirect bandgap to give a long photocarrier lifetime and …


Characterization And Coherent Spin Selective Manipulation Of Quantum Dot Energy Levels, Tristan Anthony Wilkinson Jan 2022

Characterization And Coherent Spin Selective Manipulation Of Quantum Dot Energy Levels, Tristan Anthony Wilkinson

Graduate Theses, Dissertations, and Problem Reports

Semiconductor quantum dots (QDs) are promising candidates to fulfill a wide range of applications in real-world quantum computing, communication, and networks. Their excellent optical properties such as high brightness, single-photon purity, and narrow linewidths show potential utility in many areas. In order to realize long term goals of integration into complex and scalable quantum information systems, many current challenges must be overcome. One of these challenges is accomplishment of all necessary computing operations within a QD, which might be enabled by coherent manipulation of single QD energy level structures. In the realm of scalability for quantum devices, a way to …


Polychromatic Colorings Of Certain Subgraphs Of Complete Graphs And Maximum Densities Of Substructures Of A Hypercube, Ryan Tyler Hansen Jan 2022

Polychromatic Colorings Of Certain Subgraphs Of Complete Graphs And Maximum Densities Of Substructures Of A Hypercube, Ryan Tyler Hansen

Graduate Theses, Dissertations, and Problem Reports

If G is a graph and H is a set of subgraphs of G, an edge-coloring of G is H-polychromatic if every graph from H gets all colors present in G on its edges. The H-polychromatic number of G, polyHG, is the largest number of colors in an H-polychromatic coloring. We determine polyHG exactly when G is a complete graph on n vertices, q a fixed nonnegative integer, and H is the family of one of: all matchings spanning n-q vertices, all 2-regular graphs spanning at least n-q vertices, or all cycles of length precisely n-q. …


Frayed Connections: How Long-Term Nitrogen Additions Disrupt Plant-Soil Interactions And The Carbon Cycle Of A Temperate Forest, Brooke A. Eastman Jan 2022

Frayed Connections: How Long-Term Nitrogen Additions Disrupt Plant-Soil Interactions And The Carbon Cycle Of A Temperate Forest, Brooke A. Eastman

Graduate Theses, Dissertations, and Problem Reports

Forests are expected to mitigate some of the negative effects of climate change by sequestering anthropogenic carbon (C) from the atmosphere, but the degree to which they drawn down C will depend on the availability of key nutrients, such as nitrogen (N). There is a fair amount of uncertainty in the future of the forest C sink, mostly owing to the fate of soil organic matter (SOM) and soil heterotrophic respiration to future conditions. In N limited systems, plants allocate a significant amount of their photosynthate belowground for the acquisition of nutrients, but under conditions of chronic N deposition, plants …


Tandem Addition/Fragmentation Reactions Of Vinylogous Acyl Sulfonates, Kristen S. Nerbecki Jan 2022

Tandem Addition/Fragmentation Reactions Of Vinylogous Acyl Sulfonates, Kristen S. Nerbecki

Graduate Theses, Dissertations, and Problem Reports

Fragmentation methodology has been used in organic synthesis to produce complex organic compounds. This work is focused on fragmentation reactions leading to the subsequent construction of neopentylene-fused carbocycles, which are found in several important natural products and are difficult to prepare. These are produced by utilizing an optimized fragmentation methodology from the Dudley group. The methodologies build starting materials called nonaflates and triflates with a gem-dimethyl substituent that is seen in many natural products. Nonaflates and triflates are similar in structure, but nonaflates pose benefits that are an advantage over triflates, like cost effective synthesis and more stable compounds. A …


New Techniques In Celestial Mechanics, Ali Abdulrasool Abdulhussein Jan 2022

New Techniques In Celestial Mechanics, Ali Abdulrasool Abdulhussein

Graduate Theses, Dissertations, and Problem Reports

It is shown that for the classical system of the N body problem ( Newtonian Motion), if the motion of the N particles starts from a planar initial motion at t=t_{0}, then the motion of the N particles continues to be planar for every t\in[t_{0},t_{1}], assuming that no collisions occur between the N particles. Same argument is shown about the linear motion, namely, for the classical system of the N body problem, if the motion of the N particles starts from a linear initial motion at t=t_{0}, then the motion of the N particles continues to be linear for every …


Novel Modes Of Synchronization And Extreme Events In Coupled Chemical Oscillators, David Allen Mersing Jan 2022

Novel Modes Of Synchronization And Extreme Events In Coupled Chemical Oscillators, David Allen Mersing

Graduate Theses, Dissertations, and Problem Reports

We experimentally and computationally investigate dynamical behaviors in coupled chemical oscillators. These networks of chemical oscillators are created using catalytic Ru(bpy)32+ loaded cation exchange beads submerged in catalyst-free Belousov-Zhabotinsky (BZ) solutions. Various network structures are created by utilizing the photosensitive nature of the Ru(bpy) 32+ catalyst. The response of the oscillators due to light stimuli can be characterized by constructing a phase response curve (PRC). The PRC quantifies the excitatory and inhibitory responses of BZ oscillators due to applied light perturbations as a function of the oscillators' phase. Different initial concentrations of reactants in the BZ reaction …


Modeling, Fabrication, And Characterization Of Rf-Based Passive Wireless Sensors Composed Of Refractory Semiconducting Ceramics For High Temperature Applications, Kavin Sivaneri Varadharajan Idhaiam Jan 2022

Modeling, Fabrication, And Characterization Of Rf-Based Passive Wireless Sensors Composed Of Refractory Semiconducting Ceramics For High Temperature Applications, Kavin Sivaneri Varadharajan Idhaiam

Graduate Theses, Dissertations, and Problem Reports

Real-time health monitoring of high temperature systems (>500oC) in harsh environments is necessary to prevent catastrophic events caused by structural failures, varying pressure, and chemical reactions. Conventional solid-state temperature sensors such as resistance temperature detectors (RTDs) and thermocouples are restricted by their operating environments, sensor dimensions and often require external power sources for their operation. The current work presents the research and development of RF-based passive wireless sensing technology targeting high temperatures and harsh environmental conditions. Passive wireless devices are generally classified as near-field and far-field devices based on the interrogation distance. Near-field sensors are placed at …


Regional Correlation And Depositional History Using Well Log And Core Data Of The Geneseo-Burket From The Poseidon 8m Well, Westmoreland County Pa, Usa, Spencer Leonard Williams Jr. Jan 2022

Regional Correlation And Depositional History Using Well Log And Core Data Of The Geneseo-Burket From The Poseidon 8m Well, Westmoreland County Pa, Usa, Spencer Leonard Williams Jr.

Graduate Theses, Dissertations, and Problem Reports

Abstract

Regional Correlation and Depositional History using Well Log and Core Data of the Geneseo-Burket from the Poseidon 8M Well, Westmoreland County PA, USA



Spencer Williams

Natural gas producers have invested billions of dollars in Pennsylvania and West Virginia to establish significant gas production from the Devonian Marcellus Shale and the deeper Ordovician Utica-Point Pleasant interval. In addition, commercial gas production has been reported from several other Devonian shale units in the Appalachian region, including the Rhinestreet, Levanna, and Geneseo-Burket. The Marcellus Shale is the largest natural gas play in the United States. The Marcellus is located directly under the …


Assessment Of Quechers Extraction Protocol For The Lc-Ms/Ms Detection Of Emerging Fentanyl Analogs In Biological Specimens For Clinical And Forensic Purposes, Kylea M. Morris Jan 2022

Assessment Of Quechers Extraction Protocol For The Lc-Ms/Ms Detection Of Emerging Fentanyl Analogs In Biological Specimens For Clinical And Forensic Purposes, Kylea M. Morris

Graduate Theses, Dissertations, and Problem Reports

Drug abuse within the United States is a dynamic and pervasive issue that affects the quality and life expectancy of our society. One of the major drug classes that are constantly utilized is opioids. Opioids are prescribed for pain management in patients suffering from cancer and other medical illnesses. Long-term use of opioids could lead to tolerance in humans, which poses a risk of reaching fatal overdose levels. Unfortunately, opioids are abused recreationally, and in some instances, individuals are unaware of the presence of dangerous synthetic drugs like fentanyl, hidden in materials such as heroin, cocaine, oxycodone, and methamphetamine. Recent …


Pathfinding Fast Radio Bursts Localizations Using Very Long Baseline Interferometry, Pranav Rohit Sanghavi Jan 2022

Pathfinding Fast Radio Bursts Localizations Using Very Long Baseline Interferometry, Pranav Rohit Sanghavi

Graduate Theses, Dissertations, and Problem Reports

Fast radio bursts (FRBs) are millisecond-duration, bright radio transients of extragalactic origin. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope’s CHIME/FRB instrument and other radio telescopes across the globe have detected hundreds of FRBs. Their origins are a mystery. Precise localization within the host is critical to distinguish between progenitor models. This can be achieved through Very Long Baseline Interferometry (VLBI). Until now, VLBI localizations have only been carried out in targeted follow-up observations of some repeating sources which comprise a small fraction of the FRBs.

For this work, an interferometric array of 6m dishes was constructed at the Green …


Electrochemical And Mass Spectrometry Methods For Identification Of Gunshot Residues (Gsr) In Forensic Investigations, Kourtney A. Dalzell Jan 2022

Electrochemical And Mass Spectrometry Methods For Identification Of Gunshot Residues (Gsr) In Forensic Investigations, Kourtney A. Dalzell

Graduate Theses, Dissertations, and Problem Reports

Gun violence continues to be one of most significant challenges straining the USA society causing thousands of human lives lost every year. In 2020 alone, firearm-related incidents including homicide, accidents, and suicides, reached a staggering number of over 43,000.1,2 With the increase in these types of incidents, several service areas in crime laboratories are heavily impacted by the number of cases run on a yearly basis. These include firearm examinations, gunshot residue (GSR) analysis, bullet hole identification, and shooting distance determination, which are crucial to support a criminal investigation and, overall, the justice system in our country. These areas …


A Domain Adaptation Approach For Segmenting Cell Instances In Microscopy Data, Matthew R. Keaton Jan 2022

A Domain Adaptation Approach For Segmenting Cell Instances In Microscopy Data, Matthew R. Keaton

Graduate Theses, Dissertations, and Problem Reports

Automated cellular instance segmentation is a process that has been utilized for accelerating biological research since before the deep learning era, and recent advancements have produced higher quality results with less effort from the biologist. Most current endeavors focus on completely cutting the researcher out of the picture by generating highly generalized models. However, these models invariably fail when faced with novel data and effectively opt to miss out on the full capabilities of deep learning in pursuit of this goal. In our work, we demonstrate how, with even a minimal amount of annotated data, dominant approaches in this space …


Study Of Resonantly Stabilized Radicals In Combustion Environments, James H. Lee Jan 2022

Study Of Resonantly Stabilized Radicals In Combustion Environments, James H. Lee

Graduate Theses, Dissertations, and Problem Reports

Resonantly stabilized radicals (RSRs) play an important role in combustion environments due to their high stability resulting from resonance. Many RSRs such as the propargyl, allyl, or benzyl radicals are precursors to the formation of polycyclic aromatic hydrocarbons (PAHs), which can aggregate to form soot. Due to their stability, these RSRs can accumulate in combustion environments in significant quantities. The primary way these radical species are consumed in flames or by reactions with other abundant radicals, by self-recombination of propargyl to form benzene, or in the form of other abundant radicals such as the hydroxyl radical. Experimentally determining the pathways …


Evaluating The Validity And Reliability Of Textile And Paper Fracture Characteristics In Forensic Comparative Analysis, Zachary Bailey Andrews Jan 2022

Evaluating The Validity And Reliability Of Textile And Paper Fracture Characteristics In Forensic Comparative Analysis, Zachary Bailey Andrews

Graduate Theses, Dissertations, and Problem Reports

In a comparative forensic analysis, an examiner can report that a physical fit exists between two torn or separated items when they realign in a manner unlikely to be replicated. Due to the common belief that it is unlikely that two unrelated fractured objects would match with distinctive characteristics, a physical fit represents the highest degree of association between two items. Nonetheless, despite the probative value that this evidence could have to a trier of fact, few studies have demonstrated such assumptions' scientific validity and reliability. Moreover, there is a lack of consensus-based standard protocols for physical fit comparisons, making …


Using Landsat-Based Phenology Metrics, Terrain Variables, And Machine Learning For Mapping And Probabilistic Prediction Of Forest Community Types In West Virginia, Faith M. Hartley Jan 2022

Using Landsat-Based Phenology Metrics, Terrain Variables, And Machine Learning For Mapping And Probabilistic Prediction Of Forest Community Types In West Virginia, Faith M. Hartley

Graduate Theses, Dissertations, and Problem Reports

This study investigates the mapping of forest community types for the entire state of West Virginia, USA using Global Land Analysis and Discovery (GLAD) Phenology Metrics analysis ready data (ARD) derived from the Landsat time series and digital terrain variables derived from a digital terrain model (DTM). Both classifications and probabilistic predictions were made using random forest (RF) machine learning (ML) and training data derived from ground plots provided by the West Virginia Natural Heritage Program (WVNHP). The primary goal of this study is to explore the use of globally consistent ARD data for operational forest type mapping over a …


Synthetic Methods For Improved Scope And Efficiency Of Copper-Catalyzed Regioselective Alkene Boracarboxylation, Steven William Knowlden Jan 2022

Synthetic Methods For Improved Scope And Efficiency Of Copper-Catalyzed Regioselective Alkene Boracarboxylation, Steven William Knowlden

Graduate Theses, Dissertations, and Problem Reports

The synthesis of carboxylic acids is important to the chemistry community, owing to the broad applicability of these compounds as fine chemicals and pharmaceuticals. Method development over the last decade has focused on the preparation of carboxylic acids through transition metal catalysis utilizing CO2 as a C1 synthon. Copper-catalyzed heteroelement(bora and sila)-carboxylation protocols provide functional group rich carboxylic acid products, yet remain underdeveloped and thus underutilized. Consequently, catalytic reductive difunctionalization methodologies in which CO2 and B(pin) (pin = pinacolate: 2,3-dimethyl-2,3-butanediolate) are installed across the double bond of a vinyl arene were recently developed. These boracarboxylation protocols provided novel, …


Advancing Compound Detection And Identification Using Vibrating Sharp-Edge Spray Ionization, Anthony Paul Debastiani Jan 2022

Advancing Compound Detection And Identification Using Vibrating Sharp-Edge Spray Ionization, Anthony Paul Debastiani

Graduate Theses, Dissertations, and Problem Reports

Advancing Compound Detection and Identification Using Vibrating Sharp-Edge Spray Ionization

Anthony Paul DeBastiani

‘Omics consists of various areas, including genomics, proteomics, lipidomics, and metabolomics with a goal of detection and identification of biomolecules present within each of these classes within an organism. Current omic analytical methods include the use of mass spectrometry (MS) coupled with various separation techniques, including liquid chromatography (LC), with the use of heated nebulization gas assisted electrospray ionization (HESI). Although the rapid progress in LC-MS platform development has lead to significant enhancements in omic studies, significant limitations in the detection and identification of low abundant species …


Charge Dynamics Of Inas Quantum Dots Under Resonant And Above-Band Excitation, Gary R. Lander Jr Jan 2022

Charge Dynamics Of Inas Quantum Dots Under Resonant And Above-Band Excitation, Gary R. Lander Jr

Graduate Theses, Dissertations, and Problem Reports

Research involving light-matter interactions in semiconductor nanostructures has been an interesting topic of investigation for decades. Many systems have been studied for not only probing fundamental physics of the solid state, but also for direct development of technological advancements. Research regarding self-assembled, epitaxially grown quantum dots (QDs) has proven to be prominent in both regards. The development of a reliable, robust source for the production of quantum bits to be utilized in quantum information protocols is a leading venture in the world of condensed matter and solid-state physics. Fluorescence from resonantly driven QDs is a promising candidate for the production …


On Generalizations Of Supereulerian Graphs, Sulin Song Jan 2022

On Generalizations Of Supereulerian Graphs, Sulin Song

Graduate Theses, Dissertations, and Problem Reports

A graph is supereulerian if it has a spanning closed trail. Pulleyblank in 1979 showed that determining whether a graph is supereulerian, even when restricted to planar graphs, is NP-complete. Let $\kappa'(G)$ and $\delta(G)$ be the edge-connectivity and the minimum degree of a graph $G$, respectively. For integers $s \ge 0$ and $t \ge 0$, a graph $G$ is $(s,t)$-supereulerian if for any disjoint edge sets $X, Y \subseteq E(G)$ with $|X|\le s$ and $|Y|\le t$, $G$ has a spanning closed trail that contains $X$ and avoids $Y$. This dissertation is devoted to providing some results on $(s,t)$-supereulerian graphs and …


Understanding Surface Water--Groundwater Connectivity And Discharge In Arctic Deltas, Lindsey N. Aman Jan 2022

Understanding Surface Water--Groundwater Connectivity And Discharge In Arctic Deltas, Lindsey N. Aman

Graduate Theses, Dissertations, and Problem Reports

Increased warming is driving unprecedented hydrologic changes within arctic deltas with implications for water storage, solute processing, and terrestrial and marine ecology. Thermokarst lakes within Arctic deltas store flood waters and filter solutes and sediments, thus moderating the impact of flood water discharge to arctic seas. However, this moderating influence is diminishing as lakes shrink on annual and seasonal time scales, especially close to active channels where lakes are shrinking most rapidly. This study investigates surface water-groundwater connectivity in arctic delta plains with coupled flow and heat transport models to provide a mechanistic understanding of how lake-channel proximity will impact …


Identifying And Minimizing Sources Of Variability Within Modern Spectroscopic Techniques For The Forensic Analysis Of Glass, Oriana Christy Ovide Jan 2022

Identifying And Minimizing Sources Of Variability Within Modern Spectroscopic Techniques For The Forensic Analysis Of Glass, Oriana Christy Ovide

Graduate Theses, Dissertations, and Problem Reports

Broken glass is a trace material frequently found at crime scenes such as hit-and-runs, burglaries, assaults, and homicides. Existing research encompassing the forensic analysis of glass evidence is vast. Published studies cover the analysis and interpretation of various types of glass. However, organizations such as the National Institute of Justice (NIJ), National Institute of Standards and Technology Organization of Scientific Area Committees (NIST-OSAC), and American Society of Trace Evidence Examiners (ASTEE) continue to identify glass-specific research needs to strengthen the scientific foundations of the field. Current gaps within the forensic glass community involve understanding modern glass formulations, re-evaluating the performance …


Synthesis And Cyclotrimerization Of Sulfonyl Enynes, Alexa C. Martin Jan 2022

Synthesis And Cyclotrimerization Of Sulfonyl Enynes, Alexa C. Martin

Graduate Theses, Dissertations, and Problem Reports

The synthesis of complex, polysubstituted aromatic rings from simple, non-aromatic building blocks is a consistent challenge to the synthetic community. Neopentylene ring fusions are found in several natural products but are largely absent from synthetic compound libraries. This discrepancy reflects the limitations in modern chemical synthesis. Utilizing, in part, a thoroughly developed fragmentation/olefination methodology from the Dudley Lab, a library of novel 1-sulfonyl-1,6-enynes have been developed. In this methodology, they are prepared in three steps from dimedone (5,5-dimethyl-1,3-cyclohexanedione), an inexpensive starting material. A total of 14 novel 1-sulfonyl-1,6-enynes were synthesized. These substrates were subjected to a novel benzannulation reaction based …


Examining Evolutionary Rate In Xiphosura, Samantha B. Ocon Jan 2022

Examining Evolutionary Rate In Xiphosura, Samantha B. Ocon

Graduate Theses, Dissertations, and Problem Reports

Horseshoe crabs, a group of aquatic chelicerate arthropods of the class Xiphosura, are strongly linked with the concept of “living fossils” – a term colloquially used to refer to clades that display a consistently low rate of morphological evolution through time. The concept of living fossils has been hotly debated, as it is considered to simplify or obscure millennia of evolutionary change. Recent methodological and computational advances in the paleobiological sciences have allowed for the investigation of these claims. Xiphosura are a model taxon for this type of investigative study because they exhibit a complex evolutionary history, despite their reputation …


Deep Radio Observations And The Role Of The Cosmic Web In Galaxy Evolution, Nicholas M. Luber Jan 2022

Deep Radio Observations And The Role Of The Cosmic Web In Galaxy Evolution, Nicholas M. Luber

Graduate Theses, Dissertations, and Problem Reports

A current open question in the evolution of galaxies, is what are the physical mechanisms that cut off galaxies from their primordial gas reservoirs, resulting in the end of their star-formation capabilities? Recent observational programs have shown that the properties of galaxies show dependencies on their placement within the large-scale structure (LSS) of the universe. These observations have motivated recent developments in theoretical work that have shown how a galaxy's interaction with the LSS may impact its connection to primordial gas supply, and ability to continue to accrete gas, the fundamental ingredient in star-formation.

In order to investigate the role …