Physical Sciences and Mathematics Commons^™

Modeling Moose Habitat Use And Fitness Consequences Of Habitat Selection In Vermont, Usa, Joshua Alexander Blouin

Graduate College Dissertations and Theses

The moose (Alces alces) population has been declining across the northeastern US largely due to the impacts of winter ticks (Dermacentor albipictus). In epizootic years, an individual moose can host a staggering number of ticks (> 60,000), affecting both survival and reproduction. Habitat management may be used to improve the status of the moose population and health of individuals, but this requires knowledge of key habitat types used by moose and their spatial distribution. We investigated 1) habitat use by moose and 2) the fitness consequences of habitat selection during two critical winter tick life stages in northeastern Vermont. To …

Shaping Soil: Examining Relationships Between Agriculture And Climate Change, Lindsay Barbieri

Graduate College Dissertations and Theses

As the ripple-effects of a changing climate shape our planet, understanding relationships between agriculture and climate change is critical. With agricultural practices shaping soils on over a third of the earth’s land surface, the soils and lands where food is produced are integral grounds for examining these relationships. While not all humans practice agriculture in similar or damaging ways, nevertheless, dominant agricultural practices are displacing beings and ecosystems and perturbing global nutrient cycles across the planet. These entwined imbalances of dominance and nutrients result in flows of excess nitrogen, phosphorus, and carbon that are responsible for nearly three-fourths of the …

Nonlinear Impedance Spectroscopy To Characterize Hole Transport And Recombination Dynamics In Organic Semiconductor Devices, Robin Rice

Graduate College Dissertations and Theses

Impedance Spectroscopy (IS) is an increasingly common technique to characterize both solid state and electrochemical systems including solar cells and light emitting diodes (LEDs). However, IS relies on a system response being linear with its input such that a time invariant impedance can be defined. This is usually achieved by a small amplitude input. However, doing so suppresses responses of the nonlinear processes which are of considerable interest to those designing and optimizing these devices, such as charge carrier recombination and space charge effects. This investigation employs the recently developed nonlinear extension to IS (NLIS) based in Fourier analysis of …

Two-Dimensional Bose–Hubbard Model For Helium On Graphene, Jiangyong Yu

Graduate College Dissertations and Theses

An exciting development in the field of correlated systems is the possibilityof realizing two-dimensional (2D) phases of quantum matter. For a systems of bosons, an example of strong correlations manifesting themselves in a 2D environment is provided by helium adsorbed on graphene. We construct the effective Bose-Hubbard model for this system which involves hard-core bosons (U ≈ ∞) and repulsive nearest-neighbor (V > 0) interactions. In this work, we focus on the calculations of single particle properties of the model such as the hopping parameter t. This is accomplished via Wannier Theory and Band structure calculations, which proves to be reliable …

Multiscale Assessment Of Drinking Water Treatment Residuals As A Phosphorus Sorbing Amendment In Stormwater Bioretention Systems, Michael Rick Ament

Graduate College Dissertations and Theses

Bioretention systems can reduce stormwater runoff volumes and filter pollutants. However, bioretention soil media can have limited capacity to retain phosphorus (P), and can even be a P source, necessitating P-sorbing amendments. Drinking water treatment residuals (DWTRs) have promise as a bioretention media amendment due to their high P sorption capacity. This research explores the potential for DWTRs to mitigate urban P loads using a combination of lab experiments, field trials, and an urban watershed model.

In the laboratory portion of this research, I investigated possible tradeoffs between P retention and hydraulic conductivity in DWTRs to inform bioretention media designs. …

Evaluating The Distributional Equity Of Ecosystem Services Under Land Use And Climate Change Scenarios, Jesse David Gourevitch

Graduate College Dissertations and Theses

Nature supports human well-being and sustainable development through the provision of ecosystem services (ES). While ES have been mapped, modeled, and valued with multiple methods by a wide range of disciplines, understanding the distribution of ES benefits among individuals and groups within society remains a critical gap. Addressing this gap is essential for making conservation and environmental policy-making more equitable. In this dissertation, I present four studies that evaluate the distribution of ES among demographic and socioeconomic groups under a range of land use and climate change scenarios.

In my first chapter, I project changes in the supply, demand, and …

Spillover, Dilution, And Coinfection: Understanding The Spread Of Disease Within Managed And Native Bee Communities., Phillip A. Burnham

Graduate College Dissertations and Theses

Maintaining healthy pollinator communities is vital both for ensuring food securityand ecological diversity. However, managed honeybees and wild bee communities are under threat from an array of stressors including habitat loss, global change, pesticide use, poor beekeeping, and various pests and pathogens. Pathogens have been shown to be spilling over from managed bees into wild bee populations and are known to adversely affect colony function as well as increase mortality. Understanding transmission mechanisms related to general dynamics in this system will not only benefit pollinator health, but also gives us insight into important and understudied topics in disease ecology. In …

Quantifying Proverb Dynamics In Books, News Articles, And Tweets, Ethan Davis

Graduate College Dissertations and Theses

Proverbs are an essential component of language and culture, and though much attention has been paid to their history and currency, there has been comparatively little quantitative work on the frequency with which they are used, and the dynamics of their use over time. With wider availability of large corpora reflecting many diverse genres of documents, it is now possible to take a wider view of the importance of the proverb. Can a corpus linguistic approach to phraseology support existing histories, and what further insight can be gained from a quantitative approach? This study measures temporal changes in the relevance …

Policy And Economic Variables Influencing Adoption Of Sustainable Electrification In Rural Sub-Saharan Africa, Payne William Morgan

Graduate College Dissertations and Theses

Limited access to electricity remains a primary constraint to economic growth and the improvement of livelihoods throughout sub-Saharan Africa. In rural areas, electricity access is especially sparse. The reasons for the scarcity of electricity supply in the region are well documented, with low population density, limited household incomes, and poor regulatory institutions compounding to often make the investment of expanding electricity access result in poor or risky economic returns. However, the declining cost of solar PV and mandates for clean energy development throughout the region have created new channels for bringing electricity supply in potentially more cost-effective ways.Despite these macro …

Assessing The Impact Of Changes In Acid Deposition On Dissolved Organic Carbon Mobilization From Two Forested Headwater Catchments: A Combined Lab And Field Study, Caitlin Bristol

Graduate College Dissertations and Theses

Over the past few decades, dissolved organic carbon (DOC) concentrations in headwater streams in the northern hemisphere changed. Because these changes in DOC coincided with decreased acid deposition, a potential link was proposed early on. More recent research indicated that catchment attributes, especially soil characteristics and the presence of Ca-bearing minerals, play an important role in modulating DOC release from watersheds, but further research is necessary.

To investigate the role of catchment characteristics on DOC dynamics, I use several watersheds in the Northeastern United States with similar attributes and well-constrained differences. Sleepers River Research Watershed (SRRW) has naturally occurring Calcium …

Distinguishing Different Styles Of Transpressional Deformation At An Obliquely Convergent Plate Margin, Fiordland, New Zealand, Emily Sarah Lincoln

Graduate College Dissertations and Theses

Fiordland, New Zealand provides one of the best-known and deepest (to 65 km) exposures of an Early Cretaceous magmatic arc root known to geologists. These exposures allow for us to study tectonic deformational processes at varying crustal depths, including the role of pre-existing structures on later reactivation. The well-preserved Grebe shear zone (GSZ) marks the boundary between major basement terranes in southern Fiordland and has undergone multiple episodes of deformation during the Cretaceous and Cenozoic time periods. The primary focus of this study is to recognize and characterize the differing phases of deformation that occurred along this shear zone. To …

Perils And Pitfalls Of Symbolic Regression, Ryan Grindle

Graduate College Dissertations and Theses

The ever-growing accumulation of data makes automated distillation of understandable models from that data ever-more desirable. Deriving equations directly from data using symbolic regression, as performed by genetic programming, continues its appeal due to its algorithmic simplicity and lack of assumptions about equation form. However, few models besides a sequence-to-sequence approach to symbolic regression, introduced in 2020 that we call y2eq, have been shown capable of transfer learning: the ability to rapidly distill equations successfully on new data from a previously unseen domain, due to experience performing this distillation on other domains. In order to improve this model, it is …

Exploring Hidden Networks Yields Important Insights In Disparate Fields Of Study, Laurence Clarfeld

Graduate College Dissertations and Theses

Network science captures a broad range of problems related to things (nodes) and relationships between them (edges). This dissertation explores real-world network problems in disparate domain applications where exploring less obvious "hidden networks" reveals important dynamics of the original network.

The power grid is an explicit network of buses (e.g., generators) connected by branches (e.g., transmission lines). In rare cases, if k branches (a k-set) fail simultaneously, a cascading blackout may ensue; we refer to such k-sets as "defective". We calculate system risk of cascading failure due to defective 2-sets and 3-sets in synthetic test cases of the Polish and …

Organic Amendments Alter Soil Hydrology And Belowground Microbiome Of Tomato (Solanum Lycopersicum), Taylor Readyhough

Graduate College Dissertations and Theses

Manure-derived organic amendments are a cost-effective tool that provide many potential benefits to plant and soil health. For example, amendment applications may increase soil fertility, improve soil structure, stimulate microbial activity, and suppress plant pathogens. Yet, responses to these applications may have unintended consequences. Inherent variability in the physical, chemical, and biological characteristics of these materials can result in inconsistent outcomes observed after their application. These differences are manifested in plant growth, soil physiochemical properties, and soil microbial community composition. Popular manure-derived organic amendments include dairy manure compost and poultry manure pellets. Dairy manure is an abundant resource on many …

Phosphorus And Nitrogen Losses In Runoff From Fields With And Without Tile Drainage, Leanna Thalmann

Graduate College Dissertations and Theses

Nutrient losses in surface and subsurface drainage from crop fields have important water quality implications. The deterioration of water quality in segments of Lake Champlain has led to efforts to reduce phosphorus (P) and nitrogen (N) export from agricultural fields. This thesis presents data from two years of edge-of-field monitoring in two adjacent corn (Zea mays L.) silage fields in Keeseville, New York. One field has only surface drainage improvements with monitoring equipment, and the other has both surface and subsurface drainage modifications and monitoring equipment. The study took place from October 2018 to September 2020 and quantified flow and …

Environmental Justice In Vermont’S Vulnerable Communities, Qing Ren

Graduate College Dissertations and Theses

The environmental justice (EJ) movement was initiated in the United States in the 1980s. The early focus of the movement addressed environmental racism and disproportionate exposure to pollution among communities of color and low income populations. It later evolved to include multiple dimensions of social injustice in the natural and built environment, such as food, transportation, housing, recreational spaces, and more. In this study, we used spatial analysis to identify Vermont’s environmentally vulnerable communities. We also used quantitative and qualitative methods to understand food and transportation justice in these vulnerable communities.

For the spatial analysis, we developed the Vermont Environmental …

An International Pilot Study Of Volunteer Stream Monitoring Groups: The Role Of Place Attachment In Volunteer Motivations, Rachel Pierson

Graduate College Dissertations and Theses

Engaging the public in scientific research through volunteer monitoring (a form of community science) has potential to expand knowledge of conditions and to improve collaborative decision-making. Many studies have sought to understand motivations for participation and potential resulting actions or behaviors that benefit the environment. Place-based connections have been demonstrated to lead people to adopt environmentally responsible behaviors. However, few studies have considered possible differences in motivations across countries or the role place attachment may play as a driver of initial or sustained participation.

The aim of this research was to determine the extent to which place attachment influences people’s …

After The Flood: Exploring The Influence Of Risk Perception And Decision Criteria Preference On Flood Mitigation In The Lake Champlain Richelieu River Basin, Emma Jane Spett

Graduate College Dissertations and Theses

In April of 2011, heavy rainfall paired with snow melt from the Green and Adirondack Mountains caused unprecedented flooding in the Lake Champlain Richelieu River (LCRR) basin. A study was subsequently convened by the International Joint Commission (IJC), and was tasked with identifying how flood forecasting, preparedness, and mitigation could be improved in order to reduce the impact of flooding in this transboundary watershed, and build the greater community’s resilience to flooding. A component of this study includes an assessment of the social acceptability and political feasibility of potential flood mitigation measures, which was in part carried out through the …

Movements, Habitat Use, And Abundance Of Lake Sturgeon (Acipenser Fulvescens) In Lake Champlain, Lisa K. Izzo

Graduate College Dissertations and Theses

Lake sturgeon (Acipenser fulvescens) in Lake Champlain were listed as endangered in 1972. Significant gaps exist in understanding lake sturgeon in the system as well as the methods needed to properly monitor and assess them. My research had three main goals: (1) investigate movements and habitat use of lake sturgeon in the Lake Champlain basin, (2) develop a method to estimate lake sturgeon abundance using sonar technology, and (3) test an alternative method for aging lake sturgeon.

One of the primary information gaps for lake sturgeon in Lake Champlain is an understanding of the movements and habitat use of multiple …

Characterizing Mass Loss In Central Cuba Using Long-Term Sediment Generation Rates And Rock Dissolution Rates, Mae Kate Campbell

Graduate College Dissertations and Theses

Knowledge of denudation rates over geologic timescales provides important insight into the processes that govern soil formation, the regulation of Earth’s climate, and the evolution of landscapes. Accurately establishing long-term denudation rates is also key to understanding how human actions have altered the rates and patterns of erosion over time. While cosmogenic nuclides are often used to measure long-term denudation rates at the basin scale, these rates can be unrepresentative of total landscape denudation in areas where significant mass loss occurs through rock dissolution. In tropical landscapes, mass loss by solution often represents a significant portion of total landscape mass …

Coastal Resilience At The Nexus Of Food, Energy, And Water: An Interdisciplinary Perspective For Resilience Planning, Kristin Raub

Graduate College Dissertations and Theses

Global climate change poses increased threats to coastal communities. The resilience of coastal communities relies on the protection and continued availability of essential services such as food, energy, and water (FEW) systems. However, the intersection of FEW nexus research and coastal resilience planning has not been well explored. This dissertation seeks to further the goal of operationalizing resilience planning by examining the usefulness of resilience tools and toolkits that have been developed in recent years and exploring how the FEW nexus approach has been applied to coastal resilience planning in both academic and grey literature. The first chapter provides the …

Small-Scale Roll Coating As A Transitional Stage In The Scaling Of Organic Electronic Device Fabrication Techniques, Jared Benson

Graduate College Dissertations and Theses

Incredible achievements have been made in the field of organic electronics in small-scale laboratory settings. A topic of increasing importance is the realization of the potential for these technologies to be applied in an industrial setting. This is a deceptively challenging process, considering that many of the procedures used to attain exceptional results in a laboratory setting are not viable for translation to larger scale fabrication efforts. Moreover, upscaling fabrication is further complicated by the enormous barrier of entry due to the expensive equipment required to fabricate organic electronics at larger scale as well as the exponentially greater quantity of …

Assessing Chemical And Biological Recovery From Acid Rain Deposition In Montane Vermont Lakes, Sydney Diamond

Graduate College Dissertations and Theses

Vermont’s inland lakes are changing rapidly in response to anthropogenic disturbance pressures. While changes in water chemistry are well documented across the state, the biological response of primary producer communities to these shifts remains poorly understood. This project investigated the response of phytoplankton communities to the interacting effects of recovery from acidification and climate change in high-altitude lakes. We analyzed long-term monitoring and meteorological data in four of Vermont’s acid-impaired lakes and found that as pH and acid-neutralizing capacity has increased, so have concentrations of dissolved organic carbon (DOC) in most lakes. To assess the biological response to these processes, …

Science Communication Across Diverse Ways Of Knowing And Collaboration In A Landscape-Scale Natural Resource Governance Network, Marcella M. Dent

Graduate College Dissertations and Theses

The Northwest Boreal Partnership (“Partnership”), established in 2012 as part of the U.S. Department of the Interior’s Landscape Conservation Cooperative Network, encourages cross-jurisdictional, collaborative natural resources management at a landscape scale. The Partnership is a governance network of Indigenous and non-Indigenous land managers, researchers, and local resource users from a 330-million-acre region of boreal ecosystems in Alaska and northwestern Canada. Central to the purpose of the Partnership are ideas of sharing science information to improve environmental conservation.

This case study investigated the relationship between science information and collaboration among diverse participants by drawing on theoretical frameworks related to governance networks, …

Loss Of Precision In Implementations Of The Toom-Cook Algorithm, Marcus Elia

Graduate College Dissertations and Theses

Historically, polynomial multiplication has required a quadratic number of operations. Several algorithms in the past century have improved upon this. In this work, we focus on the Toom-Cook algorithm. Devised by Toom in 1963, it is a family of algorithms parameterized by an integer, n. The algorithm multiplies two polynomials by recursively dividing them into smaller polynomials, multiplying many small polynomials, and interpolating to obtain the product. While it is no longer the asymptotically fastest method of multiplying, there is a range of intermediate degrees (typically less than 1000) where it performs the best.

Some applications, like quantum-resistant cryptosystems, require …

Investigating The Phase Of Green Leaf Volatile Derived Secondary Organic Aerosol Using An Electrical Low Pressure Impactor, Kevin Fischer

Graduate College Dissertations and Theses

Airborne particulate matter consists of small particles suspended in the air and is a ubiquitous component of the Earth’s atmosphere. These particles, known as aerosols, broadly affect both human health and the global climate. Secondary organic aerosol (SOA), a subset of atmospheric aerosol, are produced by the gas phase oxidation of volatile organic compounds (VOCs) originating from anthropogenic and biogenic sources. Of particular interest are a sub class of biogenic VOCs released by stressed plants, green leaf volatiles (GLVs), which are susceptible to oxidation via ozonolysis and form SOA. While important strides have been made in better understanding SOA, many …

Arrangements Of The Inputs And Outputs In The Multi-Robot Continuous Control Problem, Sida Liu

Graduate College Dissertations and Theses

The Multi-Robot Continuous Control (MRCC) problem in Deep Reinforcement Learning requires a single neural controller (agent) to learn to control the behavior of multiple robot bodies. When learning to control a single robot body, sensors and motors are arbitrarily connected to the input and output layers of the neural controller, respectively, and this arrangement does not affect the learnability of target robot behaviors. If and how such arrangement can affect learnability in MRCC---when dealing with multiple robots with different body plans---is as of yet unknown.

In this thesis, I demonstrate the following: (1) A neural controller can control a small …

Establishing Behavioral Baselines For Computational Systems: Two Case Studies, John Henry Ring

Graduate College Dissertations and Theses

The behavior of modern systems lives in a complex landscape that is unique to its particular application. In this work we describe and analyze the behavior of two modern computational systems: a Linux server and the National Market System (NMS). Though this work is diverse in both the type and scale of system under study, it is unified through the design and implementation of computationally tractable quantitative metrics aimed at defining the state of behavior of these systems. Understanding the behavior of these systems allows us to ensure their desired operation. In the case of a server we need to …

Lcms-Based Analysis Explains The Basis Of Oxidative Resistance In Selenium-Containing Thioredoxin Reductase, Daniel Haupt

Graduate College Dissertations and Theses

Selenocysteine (Sec) is referred to as the 21st proteogenic amino acid and is found in place of the redox-sensitive amino acid cysteine (Cys) in a small number of proteins. Sec and Cys carry out similar chemistry and are structural isomers save for a single atom difference; the former contains selenium (Se), while the latter contains sulfur (S) in the identical position. Sec poses a high bioenergetic cost for its synthesis and subsequent incorporation into protein not shared by Cys. Since Sec’s discovery in 1976, scientists have debated why certain proteins express Sec while others express Cys. In recent years, it …

Cluster Analysis Of Time Series Data With Application To Hydrological Events And Serious Illness Conversations, Ali Javed

Graduate College Dissertations and Theses

Cluster analysis explores the underlying structure of data and organizes it into groups (i.e., clusters) such that observations within the same group are more similar than those in different groups. Quantifying the ``similarity'' between observations, choosing the optimal number of clusters, and interpreting the results all require careful consideration of the research question at hand, the model parameters, the amount of data and their attributes. In this dissertation, the first manuscript explores the impact of design choices and the variability in clustering performance on different datasets. This is demonstrated through a benchmark study consisting of 128 datasets from the University …