Physical Sciences and Mathematics Commons^™

Purification And Evaluation Of Manganese Superoxide Dismutase, Madison Detullio

Senior Honors Projects

The goal of this research is to evaluate the mechanism by which p53 and SOD2 interact • Develop purification protocols for both p53 and SOD2 • Evaluate DNA binding affinity of SOD2 and p53 • Conduct a series of assays to evaluate aggregation state of p53 and SOD2 under various conditions.

A Truly Spatial Random Forests Algorithm For Geoscience Data Analysis And Modelling, Hassan Talebi, Luk J. M. Peeters, Alex Otto, Raimon Tolosana-Delgado

Research outputs 2014 to 2021

Spatial data mining helps to find hidden but potentially informative patterns from large and high-dimensional geoscience data. Non-spatial learners generally look at the observations based on their relationships in the feature space, which means that they cannot consider spatial relationships between regionalised variables. This study introduces a novel spatial random forests technique based on higher-order spatial statistics for analysis and modelling of spatial data. Unlike the classical random forests algorithm that uses pixelwise spectral information as predictors, the proposed spatial random forests algorithm uses the local spatial-spectral information (i.e., vectorised spatial patterns) to learn intrinsic heterogeneity, spatial dependencies, and complex …

A Combined Spectral And Energy Morphology Analysis Of Gamma Ray Source Hawc J2031+415 In The Cygnus Constellation, Ian Herzog

Dissertations, Master's Theses and Master's Reports

HAWC J2031+415 is a probable pulsar wind nebula (PWN) located in the Cygnus Cocoon region near a complex OB star cluster. First observed by the High-Energy-Gamma-Ray Astronomy (HEGRA) observatory in the TeV energy regime, the source had no apparent counterpart in lower energy ranges. Previous work using 1343 days of data from the High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory has determined that three sources are present in the Region of Interest (ROI): HAWC J2031+415, HAWC J2030+409 (also known as the Cocoon), and 3HWC J2020+403 (associated with the Gamma Cygni supernova remnant) \cite{Ian_01, Binita_01}.

In this work, I use the newest …

Análisis De Los Días De Mora Para La Cartera De Un Producto Financiero En Colombia, Una Aproximación A Partir De Las Series De Tiempo (2013 - 2018), Eleny Kottaridis Fernandez

Economía

La morosidad sobre la cartera de consumo evidencia un patrón que debe ser considerado en la toma de decisiones de las entidades financieras para una adecuada administración del riesgo crediticio teniendo en cuenta su alta volatilidad. En efecto, un desempeño económico desfavorable relacionado con algunos sectores financieros, las bajas tasas de crecimiento económico y mayores niveles de desempleo, incrementa la probabilidad del incumplimiento de las obligaciones de los hogares debido a la menor capacidad de pago por la reducción de sus ingresos. De acuerdo con estos impactos, las entidades financieras necesitan contar con mecanismos para abordar el pronóstico sobre el …

The Role Of Health Expenditure On Health Outcomes: Evidence In West Africa Countries., Festus Efosa Eriamiatoe

Graduate Research Theses & Dissertations

This study investigates the role of health expenditure on health outcomes in West Africa countries. Using the Grossman theoretical framework, other variables that affect health outcomes were also examined. Sixteen countries of West Africa with yearly data spanning between the period of 19 years (2000-2019) was used in this study. The health outcomes examined include life expectancy and neonatal and under-5 mortality rates. The regressors used in the study include domestic government health expenditure per capita, domestic private health expenditure per capita, external health expenditure per capita, carbon-dioxide emission metric ton per capita, human immunodeficiency virus (HIV), unemployment, GDP per …

Measure-Theoretically Mixing Subshifts With Low Complexity, Darren Creutz, Ronnie Pavlov, Shaun Rodock

Mathematics: Faculty Scholarship

We introduce a class of rank-one transformations, which we call extremely elevated staircase transformations. We prove that they are measure-theoretically mixing and, for any f : N → N with f (n)/n increasing and ∑ 1/f (n) < ∞, that there exists an extremely elevated staircase with word complexity p(n) = o(f (n)). This improves the previously lowest known complexity for mixing subshifts, resolving a conjecture of Ferenczi.

More Amazon Than Mafia: Analysing A Ddos Stresser Service As Organised Cybercrime, Roberto Musotto, David S. Wall

Research outputs 2014 to 2021

© 2020, The Author(s). The internet mafia trope has shaped our knowledge about organised crime groups online, yet the evidence is largely speculative and the logic often flawed. This paper adds to current knowledge by exploring the development, operation and demise of an online criminal group as a case study. In this article we analyse a DDoS (Distributed Denial of Service) stresser (also known as booter) which sells its services online to enable offenders to launch attacks. Using Social Network Analysis to explore the service operations and payment systems, our findings show a central business model that is similar to …

Machine Infelicity In A Poignant Visitor Setting: Comparing Human And Ai’S Ability To Analyze Discourse, Martin Maccarthy, Hairong Shan

Research outputs 2014 to 2021

This study compares the efficacy of computer and human analytics in a commemorative setting. Both deductive and inductive reasoning are compared using the same data across both methods. The data comprises 2490 non-repeated, non-dialogical social media comments from the popular touristic site Tripadvisor. Included in the analysis is participant observation at two Anzac commemorative sites, one in Western Australia and one in Northern France. The data is then processed using both Leximancer V4.51 and Dialectic Thematic Analysis. The findings demonstrate artificial intelligence (AI) was incapable of insight beyond metric-driven content analysis. While fully deduced by human analysis the metamodel was …

Marine Heatwaves In The Chesapeake Bay, Piero L. F. Mazzini, Cassia Pianca

VIMS Articles

Prolonged events of anomalously warm sea water temperature, or marine heatwaves (MHWs), have major detrimental effects to marine ecosystems and the world's economy. While frequency, duration and intensity of MHWs have been observed to increase in the global oceans, little is known about their potential occurrence and variability in estuarine systems due to limited data in these environments. In the present study we analyzed a novel data set with over three decades of continuous in situ temperature records to investigate MHWs in the largest and most productive estuary in the US: the Chesapeake Bay. MHWs occurred on average twice per …

Reconciling Models And Measurements Of Marsh Vulnerability To Sealevel Rise, Daniel J. Coleman, Mark Schuerch, (...), Matthew L. Kirwan

VIMS Articles

Tidal marsh survival in the face of sea level rise (SLR) anddeclining sediment supply often depends on the ability ofmarshes to build soil vertically. However, numerical models typically predict survival under rates of SLR that farexceedfield-based measurements of vertical accretion. Here, we combine novel measurements from sevenU.S. Atlantic Coast marshes and data from 70 additional marshes from around the world to illustrate that—over con-tinental scales—70% of variability in marsh accretion rates can be explained by suspended sediment concentratin(SSC) and spring tidal range (TR). Apparent discrepancies between models and measurements can be explained bydiffering responses in high marshes and low marshes,the …

Modeling Polar Marine Ecosystem Functions Guided By Bacterial Physiological And Taxonomic Traits, Hyewon Heather Kim, Jeff S. Bowman, (...), Deborah K. Steinberg, Scott C. Doney

VIMS Articles

Heterotrophic marine bacteria utilize organic carbon for growth and biomass synthesis. Thus, their physiological variability is key to the balance between the production and consumption of organic matter and ultimately particle export in the ocean. Here we investigate a potential link between bacterial traits and ecosystem functions in the rapidly warming West Antarctic Peninsula (WAP) region based on a bacteria-oriented ecosystem model. Using a data assimilation scheme, we utilize the observations of bacterial groups with different physiological traits to constrain the group-specific bacterial ecosystem functions in the model. We then examine the association of the modeled bacterial and other key …

Ephemeral Surface Chlorophyll Enhancement At The New England Shelf Break Driven By Ekman Restratification, H. Oliver, W. G. Zhang, K. M. Hirzel, Walker O. Smith Jr., Et Al

VIMS Articles

The Mid-Atlantic Bight (MAB) hosts a large and productive marine ecosystem supported by high phytoplankton concentrations. Enhanced surface chlorophyll concentrations at the MAB shelf-break front have been detected in synoptic measurements, yet this feature is not present in seasonal means. To understand why, we assess the conditions associated with enhanced surface chlorophyll at the shelf break. We employ in-situ and remote sensing data, and a 2-dimensional model to show that Ekman restratification driven by upfront winds drives ephemerally enhanced chlorophyll concentrations at the shelf-break front in spring. Using 8-day composite satellite-measured surface chlorophyll concentration data from 2003–2020, we constructed a …

Simple Relationships Between Residence Time And Annual Nutrient Retention, Export, And Loading For Estuaries, Jian Shen, Jiabi Du, Lisa V. Lucas

VIMS Articles

Simple mathematical models are derived from mass balances for water and transported substance to provide insight into the relationships between import, export, transport, and internal removal for nonconservative sub-stances in an estuary. Extending previous work, our models explicitly include water and substance inputs from the ocean and are expressed in terms of timescales (i.e., mean residence time and the timescale for net removal). Steady-state, timescale-based expressions for ratios of export to import, retention to import, and net export to loading, as well as for loading and annually averaged concentration, are provided. The net export:loading model explains the underlying mechanisms for …

A Novel Antibody-Based Biosensor Method For The Rapid Measurement Of Pah Contamination In Oysters, Kristen M. Prossner, George G. Vadas, Ellen Harvey, Michael A. Unger

VIMS Articles

Conventional PAH analytical methods are time-consuming and expensive, limiting their utility in time sensitive events (i.e. oil spills and floods) or for widespread environmental monitoring. Unreliable and inefficient screening methods intended to prioritize samples for more extensive analyses exacerbate the issue. Antibody-based biosensor technology was implemented as a quantitative screening method to measure total PAH concentration in adult oysters (Crassostrea virginica) — a well-known bioindicator species with ecological and commercial significance. Individual oysters were analyzed throughout the historically polluted Elizabeth River watershed (Virginia, USA). Significant positive association was observed between biosensor and GC–MS measurements that persisted when the method was …

Sediment And Terrestrial Organic Carbon Budgets For The Offshore Ayeyarwady Delta, Myanmar: Establishing A Baseline For Future Change, Evan R. Flynn, S. Kuehl, Courtney K. Harris, Matthew J. Fair

VIMS Articles

Large river deltas serve as globally important archives of terrestrial and shallow marine biogeochemical signatures and because of rapid sedimentation have the potential to impact global biogeochemical cycling. The Ayeyarwady Delta in Myanmar ranks as the world's third largest river delta in terms of sediment supply; however, modern increases in regional anthropogenic impacts risk severe alteration to sediment and TerrOC loads within this major system. By investigating modern sediment and terrestrial organic carbon (TerrOC) accumulation within the offshore Ayeyarwady Delta this study estimates baseline sediment and TerrOC budgets for this understudied mega-delta. Using 210Pb geochronology of 27 sediment cores collected …

Multi-Biomarker Analysis For Identifying Organic Matter Sources In Small Mountainous River Watersheds: A Case Study Of The Yuba River Watershed, Christina R. Pondell, Elizabeth A. Canuel

VIMS Articles

Organic matter in soils and sediments derives from a mixture of biological origins, often making it difficult to determine inputs from individual sources. Complicating the determination of source inputs to soil and sedimentary organic matter (OM) is the fact that physical and microbial processes have likely modified the initial composition of these sources. This study focused on identifying the composition of watershed-derived OM to better understand inputs to inland waters and improve our ability to resolve between terrigenous and aquatic sources in downstream systems, such as estuaries and coasts. We surveyed OM sources from the Yuba River watershed in northern …

Following The Sand Grains, Duncan M. Fitzgerald, Zoe J. Hughes, Alice Staro, Christopher J. Hein, Et Al

VIMS Articles

When longshore transport systems encounter tidal inlets, complex mechanisms are involved in bypassing sand to downdrift barriers. Here, this process is examined at Plum Island Sound and Essex Inlets, Massachusetts, USA. One major finding from this study is that sand is transferred along the coast—especially at tidal inlets—by parcels, in discrete steps, and over decadal-scale periods. The southerly orientation of the main-ebb channel at Plum Island Sound, coupled with the landward migration of bars from the ebb delta to the central portion of the downdrift Castle Neck barrier island, have formed a beach protuberance. During the constructional phase, sand is …

A Cycle Of Wind-Driven Canyon Upwelling And Downwelling At Wilmington Canyon And The Evolution Of Canyon-Upwelled Dense Water On The Mab Shelf, Haixing Wang, Donglai Gong, Marjorie A.M. Friedrichs, Courtney K. Harris, Travis Miles, Hao-Cheng Yu, Yinglong J. Zhang

VIMS Articles

Submarine canyons provide a conduit for shelf-slope exchange via topographically induced processes such as upwelling and downwelling. These processes in the Wilmington Canyon, located along the shelf-break of the Mid-Atlantic Bight (MAB), have not been previously studied, and the associated hydrographic variability inside the canyon and on the adjacent shelf are largely unknown. Observations from an underwater glider deployed in Wilmington Canyon (February 27 - March 8, 2016), along with wind and satellite altimetry data, showed evidence for a wind-driven canyon upwelling event followed by a subsequent downwelling event. Next, a numerical model of the MAB was developed to more …

Spreading And Accumulation Of River-Borne Sediments In The Coastal Ocean After The Environmental Disaster At The Doce River In Brazil, Angleo T. Lemos, Alexander Osadchiev, Piero L. F. Mazzini, Et Al

VIMS Articles

This study is focused on the fate of a large volume of mine slurry discharged from the Doce River (DR) to the coastal ocean after the worst environmental disaster in Brazilian which occurred in November 2015. We used Eulerian (ROMS) and Lagrangian (STRiPE) numerical models, as well as satellite remote sensing data, to study the spreading and seafloor accumulation of fine river-borne sediments during the initial six months following the disaster. We show that the regions of intense sediment accumulation were determined by spreading patterns of the surface-advected DR plume. The river discharge rate governed the plume surface area, while …

Status, Change, And Futures Of Zooplankton In The Southern Ocean, Nadine M. Johnston, Eugene J. Murphy, (...), Walker O. Smith Jr., Deborah K. Steinberg, Et Al

VIMS Articles

In the Southern Ocean, several zooplankton taxonomic groups, euphausiids, copepods, salps and pteropods, are notable because of their biomass and abundance and their roles in maintaining food webs and ecosystem structure and function, including the provision of globally important ecosystem services. These groups are consumers of microbes, primary and secondary producers, and are prey for fishes, cephalopods, seabirds, and marine mammals. In providing the link between microbes, primary production, and higher trophic levels these taxa influence energy flows, biological production and biomass, biogeochemical cycles, carbon flux and food web interactions thereby modulating the structure and functioning of ecosystems. Additionally, Antarctic …

Quantifying Seasonal Particulate Organic Carbon Concentrations And Export Potential In The Southwestern Ross Sea Using Autonomous Gliders, Meredith G. Meyer, Randolph G. Jones, Walker O. Smith Jr.

VIMS Articles

To assess the temporal biological and hydrographic features of the southwestern Ross Sea, we deployed a glider in a spatially restricted, ice-free area during the austral summer (1 December–6 February), and quantified from sensor measurements the particulate organic carbon (POC; via particulate backscatter) concentrations, their changes through time, and net community production (NCP; via dissolved O₂ concentrations). The POC levels could be divided into three distinct phases (I, II, and III, respectively) characterized by changes in NCP, surface-layer POC concentrations, remineralization, and export. Surface POC concentrations increased from 215 mg C m⁻³ in early December to a peak …

Comparison Of Electrochemical Polishing Treatments Between Phosphoric Acid And A Deep Eutectic Solvent For High-Purity Copper, Tarek M. Abdel-Fattah, Jon Derek Loftis

VIMS Articles

This study investigated and compared the acid-free electropolishing of copper with the state-of-the-art acidic electropolishing process. The acid-free medium used in this study is based on a deep eutectic solvent comprised of 2:1 ethylene glycol and choline chloride. The electrochemical study included voltammetry and chronoamperometry tests during the electropolishing process. The characterization techniques used were atomic force microscopy (AFM) and digital microscopy, and surface morphology comparisons summarized the electropolishing efficiency of phosphoric acid and acid-free deep eutectic solvent treatments for high-purity copper. Electropolishing copper with a deep eutectic solvent resulted in a mirror finish and a post-treatment surface that was …

Long-Term Annual Aerial Surveys Of Submersed Aquatic Vegetation (Sav) Support Science, Management, And Restoration, Robert J. Orth, William C. Dennison, Cassie Gurbisz, (...), Kenneth A. Moore, Christopher J. Patrick, (..), David J. Wilcox, Richard A. Batiuk

VIMS Articles

Aerial surveys of coastal habitats can uniquely inform the science and management of shallow, coastal zones, and when repeated annually, they reveal changes that are otherwise difficult to assess from ground-based surveys. This paper reviews the utility of a long-term (1984–present) annual aerial monitoring program for submersed aquatic vegetation (SAV) in Chesapeake Bay, its tidal tributaries, and nearby Atlantic coastal bays, USA. We present a series of applications that highlight the program’s importance in assessing anthropogenic impacts, gauging water quality status and trends, establishing and evaluating restoration goals, and understanding the impact of commercial fishing practices on benthic habitats. These …

The Spatio-Temporal Distribution And Transport Of Suspended Sediment In Laizhou Bay: Insights From Hydrological And Sedimentological Investigations, Bo Xie, Rui Bao, Dongxiao Yin, Et Al

VIMS Articles

Suspended sediment transport and deposition are crucial physical processes controlling the geomorphological evolution of estuaries and bays. Specially, under the context of worldwide coastal erosion, knowledge of the spatio-temporal distribution of suspended sediment concentration (SSC) and its associated sediment load have become increasingly important for bay management. However, our understanding of the mechanisms of suspended sediment dynamics continues to be hampered by the lack of high-resolution observations. Here, we present a study of the transport mechanisms and controlling factors of suspended sediment over Laizhou Bay. For this, we conducted continuous measurements of SSC, salinity, temperature, and flow velocity at nine …

Seasonal Controls On Nearshore Dissolved Oxygen Variability And Hypoxia In A Coastal Embayment, Ryan K. Walter, Stephen A. Huie, (...), Piero L.F. Mazzini, Ian Robbins

VIMS Articles

Declining dissolved oxygen (DO) is emerging as an increasingly important stressor in nearshore ecosystems, and there is a growing need to better understand DO dynamics and hypoxia risk in this highly variable environment. In this study, we collected data from monthly cruises on the inner shelf, continuous nearshore moorings inside and outside a small coastal upwelling embayment (San Luis Obispo Bay in Central California), and weekly phytoplankton measurements inside the bay during the upwelling season. Nearshore DO was generally dominated by low-frequency synoptic variability, with increased DO variance near the surface relative to the bottom and inside the bay compared …

Extreme Event Ecology Needs Proactive Funding, Christopher J. Patrick, Enie Hensel, John S. Kominoski, Beth A. Stauffer, William H. Mcdowell

VIMS Articles

Commentary:

Extreme events such as wildfires, hurricanes, and floods have increased in frequency and intensity. It is no longer a question of if, but rather when and where these events will occur (Stott 2016), with adverse impacts on essential ecosystem
services including clean water, harvestable materials, and carbon sequestration. In some cases, extreme events such as wildfires may have positive impacts on populations and ecosystems. Managing these impacts requires understanding how environmental context as well as ecosystem and disturbance characteristics drive system responses (Hogan et al. 2020). However, funding for ecological extreme events research, such as through the US National …

A Numerical Investigation Of Hurricane Florence-Induced Compound Flooding In The Cape Fear Estuary Using A Dynamically Coupled Hydrological-Ocean Model, Daoyang Bao, Z. George Xue, John C. Warner, Melissa Moulton, Dongxiao Yin, Et Al

VIMS Articles

Hurricane-induced compound flooding is a combined result of multiple processes, including overland runoff, precipitation, and storm surge. This study presents a dynamical coupling method applied at the boundary of a processes-based hydrological model (the hydrological modeling extension package of the Weather Research and Forecasting model) and the two-dimensional Regional Ocean Modeling System on the platform of the Coupled-Ocean-Atmosphere-Wave-Sediment Transport Modeling System. The coupled model was adapted to the Cape Fear River Basin and adjacent coastal ocean in North Carolina, United States, which suffered severe losses due to the compound flood induced by Hurricane Florence in 2018. The model's robustness was …

Local Finiteness And Automorphism Groups Of Low Complexity Subshifts, Ronnie Pavlov, Scott Schmieding

Mathematics: Faculty Scholarship

We prove that for any transitive subshift X with word complexity function c_n(X), if lim inf(log(c_n(X)/n)/(log log log n)) = 0, then the quotient group Aut(X, σ)/〈 σ〉 of the automorphism group of X by the subgroup generated by the shift σ is locally finite. We prove that significantly weaker upper bounds on c_n(X) imply the same conclusion if the gap conjecture from geometric group theory is true. Our proofs rely on a general upper bound for the number of automorphisms of X of range n in terms of word complexity, which may be …

Advancing Competency In Managing Risk And Knowledge: Steps Toward Operationalisation Of The Risk-Knowledge Infinity Cycle (Rki Cycle) Part 3: Uncovering Knowledge For Qrm Through Knowledge Mapping At Node 1, Martin Lipa, Valerie Mulholland, Anne Greene

Articles

To date, literature on the Risk-Knowledge Infinity Cycle (RKI Cycle) has mainly been theoretical. This paper series intent is to focus on the operationalisation of the RKI Cycle by describing a series of steps – the “How to” – for RKI Cycle deployment, to help move the RKI Cycle from theory to practice. The third paper in this series focuses on ensuring the best available knowledge flows into QRM through a case study demonstrating knowledge mapping to support effective quality risk assessment during commissioning and qualification activities.

Evaluating A Peer Assisted Learning Programme For Mature Access Foundation Students Undertaking Computer Programming At An Irish University, Nevan Bermingham, Frances Boylan, Barry J. Ryan

Articles

Access Foundation Programmes are a widening-participation initiative designed to encourage engagement in higher education among under-represented groups. This includes socioeconomic and educational disadvantage. Mature students in particular enrolled on these programmes experience greater difficulties making the transition to tertiary education, especially when they opt to study disciplines traditionally considered difficult. Computer programming is perceived as a traditionally difficult subject with lower pass rates and progression rates typically than other subjects.

This paper describes the first of a three-cycle action research study examining the perceived effects of a structured Peer Assisted Learning (PAL) Programme for mature students enrolled on a computer …