Physical Sciences and Mathematics Commons^™

Elements Of Biocontrol Strategies For Pheretimoid Earthworms, Maryam Nouri-Aiin

Graduate College Dissertations and Theses

Jumping worms (Megascolecidae) in the pheretimoid complex, have raisedconsiderable environmental concerns with conservationists, ecologists, policy makers, and the public. Their impacts on North American forests and high density is distinct from earthworms in other families. Most of the infested forests are near horticultural settings. Practicable options to manage their dispersal into forests do not exist. This dissertation examines the potential of an entomopathogenic fungus to control them in horticulture. It also investigates major barriers to managing their spread and studying their ecology including species identification, phenology, and genetic diversity. First, to discover the best time to apply biocontrol agents, I …

Computer Aided Design: Targeting The Pac1r For Novel Therapeutics And Investigating Biologically Relevant Materials, Kyle Thomas Mckay

Graduate College Dissertations and Theses

Computer aided drug design, a collection of computational methodologies including structure and ligand based drug design, has emerged as an efficient and accurate way to expedite the drug discovery process. Structure based drug design — methods which rely on the 3-dimensional structural information of biological targets — are of particular interest to chemists. Unfortunately, structural information can be difficult to obtain, and this can limit the usefulness of these methodologies. New methodologies and workflows, which are less reliant on difficult to obtain structural information are needed to fill in the gaps and push the drug development process forward. The first …

Tuning Electroluminescence From Resonators Based On Fabry-Pérot Microcavity Oleds, Ekraj Dahal

Graduate College Dissertations and Theses

This thesis comprises a series of methods for controlling the electroluminescence from Fabry-Pérot microcavity OLEDs by varying the resonator geometry and the location of the organic emitter within the resonator. In pursuit of this thesis, I conducted three experimental projects backed by theoretical modeling. First the thickness of the microcavity was varied to observe changes in resonant state wavelength, linewidth of the states, angular dispersion, and polarization splitting. The resulting electroluminescence can be tuned to span the entire color gamut using a single green chromophore. Electroluminescence of this green chromophore was used to pump the optical states of nominally identical …

Disentangling The Separate And Intersecting Pathways Of Carbon And Nitrogen Response To Overlapping Drivers, Manya Ruckhaus

Graduate College Dissertations and Theses

Anthropogenic activities have drastically altered atmospheric composition — leading to unprecedented disturbances that might push ecosystems across thresholds where important ecosystem services, such as clean water and healthy soils are at risk. Such disturbances include increased heavy precipitation, rain on snow events, and longer-term shifts in rain composition and precipitation amount. Catchment response to such perturbations is widely variable, indicating that specific catchment characteristics may govern the resistance and resilience of the system. Forested catchments in the northeastern, U.S. have reported increasing dissolved organic carbon (DOC) concentrations in streams, and links to shifts in drivers—such as precipitation chemistry, season, and …

Embracing Uncertainty, Ambiguity, And Complexity In Agriculture, Science, And Policy, Benjamin Timothy Dube

Graduate College Dissertations and Theses

Policy makers say they govern the environment based on scientific evidence, but environmental activists express concern about issues that challenge scientific understandings, such as risk, uncertainty, justice, and participation. This conflict is magnified in agriculture, where many social movements and farmers advocate and create farming systems that are ecological—diverse, heterogenous and adaptive. Ecological farming systems are thus harder for outside experts - researchers, extensionists, development practitioners or policymakers – to understand. Complexity and context-specificity in ecological agriculture presents numerous challenges along the path from scientific inquiry to policy implementation, including in categorizing, systematically studying, modelling and regulating farming systems. In …

On The Enhancement Of Penetrating Radar Target Location Accuracy With Visual-Inertial Slam, Joshua Girard

Graduate College Dissertations and Theses

This paper presents research concerning the use of visual-inertial Simultaneous Localization And Mapping (SLAM) algorithms to aid in Continuous Wave (CW) radar target mapping. SLAM is an established field in which radarhas been used to internally contribute to the localization algorithms. Instead, the application in this case is to use SLAM outputs to localize radar data and construct three-dimensional target maps which can be viewed in augmented reality. These methods are transferable to other types of radar units and sensors, but this paper presents the research showing how the methods can be applied to calculate depth efficiently with CW radar …

Drivers And Controls On Soil Carbon Storage In Temperate Forest Soils, Adam Noel

Graduate College Dissertations and Theses

Elevated atmospheric CO2 levels pose a threat the global climate stability but large amounts of carbon can be held within soils worldwide. Forests function to capture carbon and eventually, through litter inputs and decomposition, add this carbon to soil systems. This process is driven by climate, landscape conditions, forest and soil characteristics, that have complex interactions with one another across spatial scales. In this dissertation, I examine drivers of carbon contributions to the mineral soil, via litter decomposition and forest floor carbon pools, and how these contributions vary with forest composition and soil conditions. First, using data from a 10-year …

Characterizing Phosphorus Transport To Agricultural Tile Drains In Vermont, Ryan Andrew Ruggiero

Graduate College Dissertations and Theses

Dairy agroecosystems use subsurface or tile drainage to improve trafficability and crop yield. One of the main concerns of tile drainage is that it acts as a major source of non-point phosphorus (P) pollution because of preferential flow pathways (PFP). PFP are large conduits in the soil that allow rapid movement of water. This reduces contact time infiltrate has with deeper soil horizons, which are not saturated with P and that could act as a sink for this nutrient. Also, PFP are responsible for channeling manure applied at the surface to tile drains. The rate of tile drain installation is …

Revealing The Direct And Indirect Effects Of Climate Change On Soil Nutrient Dynamics And Forage Resources In Mountain Ecosystems, Kenna Elizabeth Rewcastle

Graduate College Dissertations and Theses

Modern climate change is already altering the structure and function ofecosystems around the world in nontrivial ways. Mountain ecosystems in particular will continue to experience a greater magnitude and rate of climatic warming than the global average, threatening the stability of key ecosystem processes like nutrient cycling as well as the supply of benefits from ecosystem services provided by mountains. While significant advancements have been made to address the direct effects of rising temperatures on nutrient cycling dynamics, our understanding of the synergies between the direct effects of warming and the indirect effects of climate change, mediated by the response …

Changing Environmental Conditions And The Response And Potential Adaptability Of Freshwater Whitefishes, Taylor R. Stewart

Graduate College Dissertations and Theses

Changes in winter conditions, such as increased temperatures and decreased ice coverage, have been observed worldwide. The responses of many lake fish populations to changing winters are projected to be inadequate to counter the speed and magnitude of climate change. Such environmental changes have been hypothesized to explain the low recruitment observed in freshwater whitefishes (Salmonidae Coregoninae). My research focused on measuring the impact changing winter conditions may have on coregonine reproductive phenology and developmental and morphological traits to better predict changes in coregonine populations as a result of climate change.

I used experimental incubation methods and modeling to explore …

Constraint-Aware And Efficiency-Aware Control Of Air-Path In Fuel Cell Vehicles, Eli Bacher-Chong

Graduate College Dissertations and Theses

Fuel cell technology offers the potential for clean, efficient, robust energy productionfor both stationary and mobile applications. But without fast and robust control systems, fuel cells cannot hope to maintain real-life efficiencies near enough to their theoretical potential. This work studies control and constraint management techniques to regulate a nonlinear multivariable air-path system for a proton exchange membrane fuel cell (PEMFC). The control objectives are to avoid oxygen starvation, run at the maximum net efficiency, achieve fast tracking of air flow and pressure set-points, and be easy to calibrate. To operate at maximum efficiency, a set-point map is generated for …

Phosphorus Dynamics In Restored Riparian Wetlands On Former Agricultural Land In Vermont, Adrian Robert Hendrick Wiegman

Graduate College Dissertations and Theses

Wetland restoration has numerous potential ecological and societal benefits, one of which is the retention of phosphorus (P) and consequent protection of downstream water bodies from eutrophication. Past studies focused on influents to and effluents from a variety of wetland types have documented net P retention. However, some wetland systems are less effective at P capture and wetland P retention capacity can change over time. Certain wetland types - especially riparian wetlands restored on former agricultural land - remain understudied. In Vermont, most of the over 4000 potential wetland restoration sites in the Lake Champlain Basin are located on current …

Multi-Scale Assessment Of Gully Erosion At Road Drainage Outlets, Emma Louise Estabrook

Graduate College Dissertations and Theses

Gully erosion and sediment deposition from roads are underrated sources of sediments entering receiving waterways. While gully erosion has been studied throughout the world, the monitoring of the temporal and spatial erosional processes related to culverts and road drainage is rare. The objectives of this study are to quantify rates of gully erosion from Vermont’s transportation drainage networks at multiple temporal scales and report on insights gained from a multi-scale approach to monitoring gully erosion. To quantify event to seasonal timescales of gully erosion, high resolution terrestrial LiDAR surveys were conducted at 13 field sites. Field sites were monitored at …

Strain-Enhanced Coherent Exciton-Polaron States In 1d Phthalocyanine Crystalline Thin Films, Libin Liang

Graduate College Dissertations and Theses

Organic semiconductors are at the forefront of materials research, due to their desired electric and mechanical properties. They offer the unique opportunity to modify material properties during synthesis process, opening an avenue to the development of novel flexible and wearable electronic and photonic devices.Molecular excitons are of importance in organic semiconductor properties. While majority of research studies are centered on achieving good control of amorphous or polycrystalline thin film properties, the static disorder effect leads to poor device performance when compared to inorganic semiconductors with superior crystalline ordering. On the other hand, the macroscopic molecular long-range ordering can enhance device …

Development Of [3,3]-Sigmatropic Rearrangements Of Zwitterionic And Cationic Intermediates Formed By Intramolecular Cyclization Of Tertiary Allylic Amines Tethered To Heterocumulenes, Joseph Pisano

Graduate College Dissertations and Theses

Guanidines are ubiquitous in nature and serve as useful building blocks in biologically active natural products as well as non-nucleophilic bases and organocatalysts. There is thus a need for methods for the synthesis of guanidine compounds as well as isoelectronic groups such as isothioureas. The 1,3-diaza-Claisen rearrangement represents a powerful reaction by which to synthesize highly substituted guanidines.

The scope of the zwitterionic 1,3-diaza-Claisen rearrangement has been further investigated through the introduction of a two-carbon tether. Electron-deficient carbodiimides can be synthesized through desulfurization of isothioureas, which undergo intramolecular cyclization through a tethered tertiary amine bearing an allylic group to afford …

Soil Invertebrates In Agriculture: Assessing Ecosystem Services, Biodiversity Impacts, And Farmer Perceptions, Eva Kinnebrew

Graduate College Dissertations and Theses

Harmonizing biological diversity and crop production is a major goal towards building more sustainable food systems. Soil invertebrates are diverse and abundant organisms in agriculture, but relatively little is known about their benefits or how agricultural management impacts them. In this dissertation, I dig into the complex interactions between agricultural land use and soil invertebrate biodiversity to better inform farmer decision-making. I find that soil invertebrate communities have major potential contributions to agroecosystems (Chapter 2) and are shaped heavily by agricultural land use (Chapters 3, 4), but remain too uncertain to contribute to farmers’ management choices (Chapter 5). First, I …

Assessing Assumptions And Applying Cosmogenic Nuclide Methods To Earth Surface Processes, Christopher T. Halsted

Graduate College Dissertations and Theses

Terrestrial in situ cosmogenic radionuclides are powerful tools for quantifying rates and durations of Earth surface processes. Among the many applications of cosmogenic radionuclides are quantification of basin-scale erosion rates, burial durations of paleosols and terrace sediments, and unraveling of glacial chronologies. In this dissertation I use large data sets to investigate methodological assumptions critical for using cosmogenic radionuclides to interpret Earth surface processes, and I apply this isotope system to reconstruct the deglacial history of the Laurentide Ice Sheet in the northeastern United States.

I use new and previously-published measurements of in situ 26Al and 10Be concentrations, over 300 …

Building A Learning Healthcare System: A Path To Optimizing Big Health Data To Inform Clinical Care Decisions, Danne Charlotte Emily Elbers

Graduate College Dissertations and Theses

The explosive growth of data and computing power of the last decades has had large impacts on a myriad of domains, not in the least on one of society’s most complex systems: healthcare. In this work, a version of the resulting Learning Healthcare System (LHS) is explored and elements of it have been implemented and are in use at the Department of Veterans’ Affairs today. After an overview of what a LHS is and what it could be once executed in its full form, the chapters will describe in detail some of the individual elements and how they address cogs …

Evolution Of Drought And Low Temperature Responses In Temperate Pooideae Grasses: Timings, Determinants, And Intersections, Aayudh Das

Graduate College Dissertations and Theses

Anthropogenically-mediated rises in atmospheric CO2 and global average temperatures is leading to increasingly severe drought and extreme weather events, the latter including unseasonal bouts of low and high temperatures. In order for plant breeders and conservation biologists to predict future responses to global warming, they must understand the ecological and evolutionary processes that shaped plant tolerance to stressful environments in the past. This is particularly true for grasses (Poaceae) that dominate approximately one-third of the Earth's vegetative cover, live in some of the world's harshest terrestrial environments, and are tremendously important, both ecologically and economically. One of the largest subfamily …

Assessing Recovery And Reuse Of Nutrients Using Grid-Based Spatial Modeling: A Case Study Of Sri Lanka, Maya Fein-Cole

Graduate College Dissertations and Theses

Identifying and implementing strategies for recovering resources from waste streams for reuse helps to minimize natural resource extraction and reduces waste generation. Spatial modeling can guide resource cycling by optimizing co-location of recovery and reuse. These models can help assess feasibility and effectiveness (e.g., meeting crop nutrient needs) of circular economy practices at a landscape scale. Though many useful models exist, there is a need for an adaptable grid-based tool to address reuse on a per area basis (e.g., kg nitrogen per hectare of cropland). A model like this could be applied to any landscape and would utilize input data …

High-Resolution Downscaling And Bias-Correction Of Temperature And Precipitation: Advances In Statistical Methods, Maike Holthuijzen

Graduate College Dissertations and Theses

High-resolution, bias-corrected climate data is necessary for climate impact studies and modeling efforts at local scales. General circulation models (GCMs) provide important information about historical and future larger-scale climate trends, but their spatial resolution is too coarse to investigate localized effects of climate processes. Additionally, raw GCM output is characterized by some degree of bias. Two post-processing procedures known as downscaling and bias-correction are typically applied to raw climate model output prior to its use in further modeling applications. Downscaling is the process in which data at a coarse spatial scale is transformed to a fine spatial scale. Bias-correction refers …

Medical Applications Of Ultrasound: T-Cell Drug Delivery, Osteoporosis Diagnosis, And Biofilm Mitigation, Alina Karki

Graduate College Dissertations and Theses

The ability of ultrasound to localize acoustic energy deposition and induce a biological effect within a target is examined in three novel biomedical applications: sonoporation, osteoporosis diagnosis, and biofilm mitigation.Ultrasound can excite encapsulated microbubbles, causing an acoustic cavitation effect in the vicinity of cells, temporarily increasing membrane permeability, and allowing cells to uptake foreign molecules. This non-viral transfection technique is called sonoporation. Our experimental study demonstrated that it could be effective for small interfering RNA (siRNA) delivery into an isolated mouse and human T-cells, which is a complex process despite its importance in treating numerous diseases. T-cells are non-proliferating, while …

Climate Adaptive Forest Management In The Northeastern Us: Social And Ecological Motivations, Barriers, And Responses Of Rural And Urban Foresters, Teresa Mcgann

Graduate College Dissertations and Theses

This project examines how foresters in a diversity of professional contexts perceive and respond to global change in the northeastern United States, with the goal of supporting foresters in broadening and deepening their use of climate adaptive strategies. Based on qualitative analysis of 32 in-depth semi-structured interviews with urban and rural foresters (n = 15 and n = 17, respectively) across New England and New York, a summary is presented of the i) important environmental drivers of adaptation; ii) commonly employed adaptive practices; iii) significant barriers to adaptation; and iv) approaches to working through named barriers. According to the motivations, …

Resonant Trojan Emris With Lisa, Vanessa Myhaver

Graduate College Dissertations and Theses

Extreme--mass--ratio inspirals (EMRI) are prospective sources for the detection of observational signals with the Laser Interferometer Space Antenna (LISA) mission, built to accurately detect and measure gravitational waves -- ripples in the curvature, and fabric of space--time. EMRIs are typically comprised of a supermassive black hole (SMBH) one million times more massive than our Sun, and a stellar--origin black hole several orders of magnitude smaller. As the smaller black hole spirals into the supermassive black hole, thousands of cycles of the gravitational waveform serve as a precision probe for the extreme space-time curvature of the system. The goal of this …

Studies On The Tempered Fractional Natural Decomposition Method, Nazek Ahmad Obeidat

Graduate College Dissertations and Theses

In Fractional Calculus (FC), the notion of fractional derivatives and integrals arise from convolutions with a power law, which, when multiplied by an exponential factor, one obtains tempered fractional derivatives and integrals.

The purpose of this dissertation is to develop theories and applications of a new technique in FC called the Tempered Fractional Natural Transform Method (TFNTM). This method can be used to solve a myriad of problems in linear and nonlinear ordinary and partial differential equations.

We present convergence analysis, give error estimates, and provide exact solutions, with graphical illustrations, to many well-known problems in tempered fractional differential equation, …

Implications Of Population Genetics And Physiological Responses On The Conservation Of Moose (Alces Alces Americana), Elias Rosenblatt

Graduate College Dissertations and Theses

Wildlife populations around the globe are facing numerous, complex challengesto their persistence, yet conservation efforts are hindered by limited information about these populations and the anthropogenic pressures they face. North American moose (Alces alces americana), despite being of ecological, cultural, and economical importance, inhabit remote landscapes, making population monitoring difficult. At the same time, many moose populations, including in Vermont and eastern North America, have experienced recent declines mainly due to winter tick (Dermacentor albipictus) epizootics. Anthropogenic landscape change and climate-mediated pressures pose future challenges for moose across the southern extent of their distribution. Though impacts of winter tick infestation …

Management For Amphibians In Complex Ecosystems, Lindsey Pekurny

Graduate College Dissertations and Theses

Effective conservation is becoming more difficult as threats to wildlife increase. Natural resource managers are pressured to make difficult decisions with limited resources, and in many instances, some degree of uncertainty. Scientists and managers tasked with the conservation of a species need tools to help guide efficient decision making. Often, information for management decisions is insufficient. Tools that help to inform decision makers and address uncertainty will be invaluable to effective conservation initiatives. Here, we create two models to help managers navigate the complexities associated with decision making. The objective our first study was to create a model to best …

Ghgs From Bmps: Examining The Factors That Mediate Soilborne Greenhouse Gas Emissions From Agricultural Best Management Practices, Sarah Brickman

Graduate College Dissertations and Theses

Agricultural best management practices (BMPs) promote soil health and achieve multiple positive environmental outcomes. However, practices that are intended to solve one environmental challenge may have unintended climate impacts, therefore presenting a potential tradeoff. For example, manure injection is a BMP that can reduce runoff and nitrogen loss as ammonia gas (NH3) but can increase N2O and CO2 emissions compared to manure broadcast application. This thesis explores how CO2 and N2O emissions from manure injection compare to other soil fertility practices as well as the conditions that may enhance or reduce these greenhouse gas (GHG) fluxes. First, during a two-year …

A Holistic Approach To River Restoration Design And Conservation Planning On The Reach And Basin Scales Using Hydraulic Modeling And Multi-Objective Optimization Tools, Lindsay Courtney Worley

Graduate College Dissertations and Theses

Flooding events around the world cost billions (USD) in damages each year. For decades, engineers have combated flood related damages by implementing flood mitigation controls such as channelization, levees or berms, and armoring. Recent advances in the study of river dynamics, however, have challenged the efficacy of these traditional flood mitigation techniques and pose that these structures are disconnecting channels from their floodplains, increasing flow rates, and contributing to more erosion. The effects of climate change combined with future predictions of increased storm frequency and intensity make it necessary to revise flood hazard mitigation strategies. A more nature-based alternative to …

Leveraging Behavioral Data For Public Health: Exploring Sleep And Nature Exposure Using Mobile Phones And Social Media, Kelsey Linnell

Graduate College Dissertations and Theses

Health surveillance and assessment are considered essential components of a func- tional public health system. The recent ubiquity of mobile devices and social media have created a wealth of behavioral data, and bring into existence new forms of pop- ulation health monitoring. These new digital sources can provide direct and passive data for more detailed and nuanced health factors, and have expanded the human, spatial, and temporal scales at which these factors can be measured. In this project, I leverage digital trace data from tweets and mobile device location pings to explore population scale sleep loss, and nature exposure through …