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University of Vermont

2018

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Articles 61 - 90 of 102

Full-Text Articles in Physical Sciences and Mathematics

The Climate-Smart Village Approach: Framework Of An Integrative Strategy For Scaling Up Adaptation Options In Agriculture, Pramod K. Aggarwal, Andy Jarvis, Bruce M. Campbell, Robert B. Zougmoré, Arun Khatri-Chhetri, Sonja J. Vermeulen, Ana Maria Loboguerrero, Leocadio S. Sebastian, James Kinyangi, Osana Bonilla-Findji, Maren Radeny, John Recha, Deissy Martinez-Baron, Julian Ramirez-Villegas, Sophia Huyer, Philip Thornton, Eva Wollenberg, James Hansen, Patricia Alvarez-Toro, Andrés Aguilar-Ariza, David Arango-Londoño, Victor Patiño-Bravo, Ovidio Rivera, Mathieu Ouedraogo, Bui Tan Yen Jan 2018

The Climate-Smart Village Approach: Framework Of An Integrative Strategy For Scaling Up Adaptation Options In Agriculture, Pramod K. Aggarwal, Andy Jarvis, Bruce M. Campbell, Robert B. Zougmoré, Arun Khatri-Chhetri, Sonja J. Vermeulen, Ana Maria Loboguerrero, Leocadio S. Sebastian, James Kinyangi, Osana Bonilla-Findji, Maren Radeny, John Recha, Deissy Martinez-Baron, Julian Ramirez-Villegas, Sophia Huyer, Philip Thornton, Eva Wollenberg, James Hansen, Patricia Alvarez-Toro, Andrés Aguilar-Ariza, David Arango-Londoño, Victor Patiño-Bravo, Ovidio Rivera, Mathieu Ouedraogo, Bui Tan Yen

Rubenstein School of Environment and Natural Resources Faculty Publications

Increasing weather risks threaten agricultural production systems and food security across the world. Maintaining agricultural growth while minimizing climate shocks is crucial to building a resilient food production system and meeting developmental goals in vulnerable countries. Experts have proposed several technological, institutional, and policy interventions to help farmers adapt to current and future weather variability and to mitigate greenhouse gas (GHG) emissions. This paper presents the climate-smart village (CSV) approach as a means of performing agricultural research for development that robustly tests technological and institutional options for dealing with climatic variability and climate change in agriculture using participatory methods. It …


Farmer Perceptions And Behaviors Related To Wildlife And On-Farm Conservation Actions, Sara M. Kross, Katherine P. Ingram, Rachael F. Long, Meredith T. Niles Jan 2018

Farmer Perceptions And Behaviors Related To Wildlife And On-Farm Conservation Actions, Sara M. Kross, Katherine P. Ingram, Rachael F. Long, Meredith T. Niles

College of Agriculture and Life Sciences Faculty Publications

Conservation Letters published by Wiley Periodicals, Inc. Policy makers are increasingly encouraging farmers to protect or enhance habitat on their farms for wildlife conservation. However, a lack of knowledge of farmers’ opinions toward wildlife can lead to poor integration of conservation measures. We surveyed farmers to assess their perceptions of ecosystem services and disservices from perching birds, raptors, and bats—three taxa commonly targeted by conservation measures. The majority of farmers thought that perching birds and bats were beneficial for insect pest control and that raptors were beneficial for vertebrate pest control; however, fruit farmers viewed perching birds more negatively than …


Novelty Detection Of Machinery Using A Non-Parametric Machine Learning Approach, Enrique Angola Jan 2018

Novelty Detection Of Machinery Using A Non-Parametric Machine Learning Approach, Enrique Angola

Graduate College Dissertations and Theses

A novelty detection algorithm inspired by human audio pattern recognition is conceptualized and experimentally tested. This anomaly detection technique can be used to monitor the health of a machine or could also be coupled with a current state of the art system to enhance its fault detection capabilities. Time-domain data obtained from a microphone is processed by applying a short-time FFT, which returns time-frequency patterns. Such patterns are fed to a machine learning algorithm, which is designed to detect novel signals and identify windows in the frequency domain where such novelties occur. The algorithm presented in this paper uses one-dimensional …


Application Of Geophysical And Geochronological Methods To Sedimentologic And Stratigraphic Problems In The Lower Cambrian Monkton Formation: Northwestern Vermont, Henry C. Maguire Jan 2018

Application Of Geophysical And Geochronological Methods To Sedimentologic And Stratigraphic Problems In The Lower Cambrian Monkton Formation: Northwestern Vermont, Henry C. Maguire

Graduate College Dissertations and Theses

The Monkton Formation of the western shelf stratigraphic sequence in Vermont (VT) is identified as a Lower Cambrian regressive sandstone unit containing parasequences recording tidal flat progradation. Previous workers identified cycles believed to represent parasequences in a portion of a 1034' deep geothermal well drilled at Champlain College in Burlington, Vermont. For this study, both outcrop and well geophysical surveys were completed to better identify gamma emission curves and relative values for parasequences and select lithologies that are indicators of bathymetry and sea level. After using physical stratigraphic techniques to assemble a composite stratigraphic section for the Monkton Formation, analysis …


Farmers Share Their Perspectives On California Water Management And The Sustainable Groundwater Management Act, Courtney Hammond Wagner, Meredith T. Niles Jan 2018

Farmers Share Their Perspectives On California Water Management And The Sustainable Groundwater Management Act, Courtney Hammond Wagner, Meredith T. Niles

College of Agriculture and Life Sciences Faculty Publications

Agriculture is the largest human use of water in California, which gives farmers a critical role in managing water to meet the goals of the Sustainable Groundwater Management Act (SGMA). To explore farmers’ perspectives on SGMA, we held focus groups with 20 farmers in Yolo County, where the groundwater basin has been given a high/medium priority under SGMA. The farmers had varying perspectives about the factors that led to SGMA and varying responses to the regulation. They suggested that drought, competing agricultural and urban uses, and an increase in perennial crops were factors in recent water use, resulting in changes …


The Impact Of Genetic Changes During Crop Domestication On Healthy Food Development, Petr Smýkal, Matthew N. Nelson, Jens D. Berger, Eric J.B. Von Wettberg Jan 2018

The Impact Of Genetic Changes During Crop Domestication On Healthy Food Development, Petr Smýkal, Matthew N. Nelson, Jens D. Berger, Eric J.B. Von Wettberg

College of Agriculture and Life Sciences Faculty Publications

No abstract provided.


The Impact Of Genetic Changes During Crop Domestication, Petr Smýkal, Matthew N. Nelson, Jens D. Berger, Eric J.B. Von Wettberg Jan 2018

The Impact Of Genetic Changes During Crop Domestication, Petr Smýkal, Matthew N. Nelson, Jens D. Berger, Eric J.B. Von Wettberg

College of Agriculture and Life Sciences Faculty Publications

Humans have domesticated hundreds of plant and animal species as sources of food, fiber, forage, and tools over the past 12,000 years, with manifold effects on both human society and the genetic structure of the domesticated species. The outcomes of crop domestication were shaped by selection driven by human preferences, cultivation practices, and agricultural environments, as well as other population genetic processes flowing from the ensuing reduction in effective population size. It is obvious that any selection imposes a reduction of diversity, favoring preferred genotypes, such as nonshattering seeds or increased palatability. Furthermore, agricultural practices greatly reduced effective population sizes …


Bottom-Up Adaptive Management And Stakeholder Participation For Clean Water And Healthy Soils In A Complex Social-Ecological System, Sarah Coleman Jan 2018

Bottom-Up Adaptive Management And Stakeholder Participation For Clean Water And Healthy Soils In A Complex Social-Ecological System, Sarah Coleman

Graduate College Dissertations and Theses

Protection of water resources in a changing climate depends on bottom-up stewardship and adaptive management. From the ground up, a vital component is maintaining soil ecosystem services that regulate water, recycle nutrients, sequester carbon, provide food, and other benefits. Interacting spatial, social, and physical factors determine agricultural and stormwater management, and their impact on water. This dissertation explores these dimensions within a complex social-ecological system. The first chapter evaluates a participatory process to elicit solutions to complex environmental problems across science, policy, and practice. The second chapter studies on-farm soil assessment and its role in informing management decisions and supporting …


Fluvial Processes In Motion: Measuring Bank Erosion And Suspended Sediment Flux Using Advanced Geomatic Methods And Machine Learning, Scott Douglas Hamshaw Jan 2018

Fluvial Processes In Motion: Measuring Bank Erosion And Suspended Sediment Flux Using Advanced Geomatic Methods And Machine Learning, Scott Douglas Hamshaw

Graduate College Dissertations and Theses

Excessive erosion and fine sediment delivery to river corridors and receiving waters degrade aquatic habitat, add to nutrient loading, and impact infrastructure. Understanding the sources and movement of sediment within watersheds is critical for assessing ecosystem health and developing management plans to protect natural and human systems. As our changing climate continues to cause shifts in hydrological regimes (e.g., increased precipitation and streamflow in the northeast U.S.), the development of tools to better understand sediment dynamics takes on even greater importance. In this research, advanced geomatics and machine learning are applied to improve the (1) monitoring of streambank erosion, (2) …


Applying Bayesian Belief Network To Understand Public Perception On Green Stormwater Infrastructures In Vermont, Qing Ren Jan 2018

Applying Bayesian Belief Network To Understand Public Perception On Green Stormwater Infrastructures In Vermont, Qing Ren

Graduate College Dissertations and Theses

Decisions of adopting best management practices made on residential properties play an important role in reduction of nutrient loading from non-point sources into Lake Champlain and other waterbodies in Vermont. In this study, we use Bayesian belief network (BBN) to analyze a 2015 survey dataset about adoption of six types of green infrastructures (GSIs) in Vermont’s residential areas. Learning BBNs from physical probabilities of the variables provides a visually explicit approach to reveal the message delivered by the dataset. Using both unsupervised and supervised machine learning algorithms, we are able to generate networks that connect the variables of interest and …


From Sea To Lake: The Depositional History Of Saint Albans Bay, Vt, Usa, Matthew Kraft Jan 2018

From Sea To Lake: The Depositional History Of Saint Albans Bay, Vt, Usa, Matthew Kraft

Graduate College Dissertations and Theses

Sediment accumulated in lakes stores valuable information about past environments and paleoclimatological conditions. Cores previously obtained from Saint Albans Bay, located in the Northeast Arm of Lake Champlain, VT record the transition from the Champlain Sea to Lake Champlain. Belrose (2015) documented the presence of a peat horizon separating the sediments of the Champlain Sea from those of Lake Champlain. Initially, this layer was thought to comprise the transition from the marine environment of the Champlain Sea to a freshwater wetland. However, based on the results from this study, the transition between marine and freshwater conditions is thought to be …


Consumer Engagement With Efficient And Renewable Energy Technology: Case Studies On Smart Meter Utilization And Support For A Community Anaerobic Biodigester System In Vermont, Samantha Whitney Lewandowski Jan 2018

Consumer Engagement With Efficient And Renewable Energy Technology: Case Studies On Smart Meter Utilization And Support For A Community Anaerobic Biodigester System In Vermont, Samantha Whitney Lewandowski

Graduate College Dissertations and Theses

Residential electricity consumption in the United States has many adverse impacts, such as greenhouse gas emissions, dependence on fossil fuels, and costs. Efficient and renewable energy technologies have the potential to help mitigate some of these impacts, but appear to be under-utilized in the United States. One major barrier to expanding the deployment of these kinds of technologies and maximizing the benefits they can provide is a lack of consumer engagement. The overall purpose of this thesis is to better understand the extent to which efficient and renewable energy technologies are being engaged with and what factors may influence such …


Networks, (K)Nots, Nucleotides, And Nanostructures, Ada Morse Jan 2018

Networks, (K)Nots, Nucleotides, And Nanostructures, Ada Morse

Graduate College Dissertations and Theses

Designing self-assembling DNA nanostructures often requires the identification of a route for a scaffolding strand of DNA through the target structure. When the target structure is modeled as a graph, these scaffolding routes correspond to Eulerian circuits subject to turning restrictions imposed by physical constraints on the strands of DNA. Existence of such Eulerian circuits is an NP-hard problem, which can be approached by adapting solutions to a version of the Traveling Salesperson Problem. However, the author and collaborators have demonstrated that even Eulerian circuits obeying these turning restrictions are not necessarily feasible as scaffolding routes by giving examples of …


Market Efficiency In U.S. Stock Markets: A Study Of The Dow 30 And The S&P 30, Colin Michael Van Oort Jan 2018

Market Efficiency In U.S. Stock Markets: A Study Of The Dow 30 And The S&P 30, Colin Michael Van Oort

Graduate College Dissertations and Theses

The U.S. National Market System (NMS), the largest marketplace in the world for securities and exchange traded funds, suffers from geographic market fragmentation which leads to reduced market efficiency.

Communication lines transmit price updates and other information between geographically isolated exchanges at varying speeds, bounded above by the speed of light.

Market participants have access to federally mandated information provided by the Securities Information Processor (SIP) and privately offered information provided by the exchanges, often called direct feeds.

These feeds are quantitatively and qualitatively distinct, with the direct feeds tending to provide more information at a faster rate than the …


Geochronological Constraints On The Timing Of Deformation: An Examination Of The Prospect Rock Fault Footwall In North-Central Vermont, Evan Tam Jan 2018

Geochronological Constraints On The Timing Of Deformation: An Examination Of The Prospect Rock Fault Footwall In North-Central Vermont, Evan Tam

Graduate College Dissertations and Theses

The Prospect Rock Fault (PRF) is key to our understanding of the regional tectonic evolution of Vermont during the Taconic, Salinic, and Acadian Orogenies, and may have played an important role in the exhumation of blueschist and eclogite-facies rocks in the Tillotson Peak Complex (TPC) during the Taconic Orogeny. The TPC is in the footwall of the PRF in the eastern limb of the Green Mountain Anticlinorium. In the TPC, the dominant foliation is S2 and E-W trending F2 folds parallel L2 stretching lineations, which trend orthogonal to regional N-S trending folds associated with the Taconic Orogeny. The PRF itself …


Combining Observations Of Soils And Streams To Investigate Trends Caused By Reduced Acid Depositon In The Sleepers River Watershed, Jesse Armfield Jan 2018

Combining Observations Of Soils And Streams To Investigate Trends Caused By Reduced Acid Depositon In The Sleepers River Watershed, Jesse Armfield

Graduate College Dissertations and Theses

Acid deposition forms when emission-derived sulfur dioxide and nitrogen oxides interact with precipitation and was particularly severe in the northeastern US. Effects of acid deposition include declining soil quality due to low pH and base cation leaching, which subsequently altered the composition of soil solution, ground water (GW) and eventually stream water. Because of the high buffering capacity of carbonates, watersheds underlain by carbonate rich rocks have received limited attention in acid deposition studies, however, carbonate weathering by strong anthropogenic acids can increase atmospheric CO2 levels.

Emission reductions due to the Clean Air Act and Amendments has led to a …


Land Use, Power, And Knowledge At The Northern Resource Frontier: Mining, Public Engagement, And Contentious Land Imaginaries In Bristol Bay And The Yukon-Kuskokwim Delta, Jonathan Tollefson Jan 2018

Land Use, Power, And Knowledge At The Northern Resource Frontier: Mining, Public Engagement, And Contentious Land Imaginaries In Bristol Bay And The Yukon-Kuskokwim Delta, Jonathan Tollefson

Graduate College Dissertations and Theses

The Donlin and Pebbles mines are two of the eight industrial-scale hard rock mines currently under the review of Alaska’s Large Mine Permitting program. Both projects promise to deliver profit and employment to their respective regions: Pebble to Bristol Bay in the southwest, and Donlin to the Yukon-Kuskokwim Delta, just north of Pebble. Both projects would also produce exceptional quantities of waste and will require almost-unprecedented infrastructure development, potentially threatening the lives and subsistence livelihoods of the Alaska Native peoples in their respective regions. The Pebble project inspired international protest and led to the emergence of a powerful resistance coalition …


Quantification Of Mouse Cardiac Troponin I And Myosin Binding Protein C Phosphorylation By Liquid Chromatography-Mass Spectrometry (Lc-Ms), Praveena Nukareddy Jan 2018

Quantification Of Mouse Cardiac Troponin I And Myosin Binding Protein C Phosphorylation By Liquid Chromatography-Mass Spectrometry (Lc-Ms), Praveena Nukareddy

Graduate College Dissertations and Theses

Heart failure is a major public health issue, with its prevalence estimated to be 6.5 million adults in the USA. Of the hospitalized heart failure (HF) cases, 50% are characterized by preserved ejection function (HFpEF). In HFpEF, the heart pumps a normal proportion of blood that enters it. However, thickening of the ventricular walls inhibits the chamber filling to normal volume. The direct basis of HFpEF is a slowed elongation of the cardiac muscle during the diastolic phase of the cardiac cycle. Elucidation of mechanisms that mediate relaxation of cardiac muscle could help understand the pathogenic mechanisms in HFpEF.

Myocardial …


No Farm Is An Island: Pollinators And Pollination In Agricultural Landscapes, Charles C. Nicholson Jan 2018

No Farm Is An Island: Pollinators And Pollination In Agricultural Landscapes, Charles C. Nicholson

Graduate College Dissertations and Theses

Productive, resilient and sustainable agricultural systems are required to meet the immediate needs of a burgeoning human population, while avoiding ecosystem collapse. Agriculture provides food, fiber, fuels and other products for our current population of 7 billion and is still the major livelihood for 40% of people worldwide. By replacing natural habitat and employing chemical inputs, agriculture also negatively impacts biodiversity and impairs the provision of ecosystem services. This poses a challenge for agriculture as these impacted services are often those required for high yielding and high-quality crop production. Evidence is accumulating that agricultural management can safeguard biodiversity and ecosystem …


The Progressive Evolution Of The Champlain Thrust Fault Zone: Insights From A Structural Analysis Of Its Architecture, Matthew Merson Jan 2018

The Progressive Evolution Of The Champlain Thrust Fault Zone: Insights From A Structural Analysis Of Its Architecture, Matthew Merson

Graduate College Dissertations and Theses

Near Burlington, Vermont, the Champlain Thrust fault placed massive Cambrian dolostones over calcareous shales of Ordovician age during the Ordovician Taconic Orogeny. Although the Champlain Thrust has been studied previously throughout the Champlain Valley, the architecture and structural evolution of its fault zone have never been systematically defined. To document these fault zone characteristics, a detailed structural analysis of multiple outcrops was completed along a 51 km transect between South Hero and Ferrisburgh, Vermont.

The Champlain Thrust fault zone is predominately within the footwall and preserves at least four distinct events that are heterogeneous is both style and slip direction. …


Pharmaceutical Waste In Vermont: Results From A Survey On Purchasing, Use & Disposal, Christine Hart Jan 2018

Pharmaceutical Waste In Vermont: Results From A Survey On Purchasing, Use & Disposal, Christine Hart

Graduate College Dissertations and Theses

Pharmaceutical waste is an emerging form of waste with significant impacts on the environment. This study reports the results of a state-wide phone survey on pharmaceutical purchasing, use and disposal behavior among Vermont residents (n = 421). The objectives of this study were: 1) to compare the demographic nature of populations who purchase and use medicaton to those associated with leftover medication, and 2) to evaluate the impact of disposal behavior in Vermont and to recommend strategies to minimize pollution. The findings of this study showed that approximately 93% of survey participants reported purchasing of medication, 60% reported leftover medication …


Conservation Of Ecosystem Services And Biodiversity In Vermont, Usa, Keri B. Watson Jan 2018

Conservation Of Ecosystem Services And Biodiversity In Vermont, Usa, Keri B. Watson

Graduate College Dissertations and Theses

Supporting a growing human population while avoiding biodiversity loss is a central challenge towards a sustainable future. Ecosystem services are benefits that people derive from nature. People have drastically altered the earth’s land surface in the pursuit of those ecosystem services that have been ascribed market value, while at the same time eroding biodiversity and non-market ecosystem services. The science required to inform a more balanced vision for land-cover change in the future is rapidly developing, but critical questions remain unanswered regarding how to quantify ecosystem services and ascribe value to them, and how to coordinate efforts to safeguard multiple …


Cargo Transport By Myosin Va Molecular Motors Within Three-Dimensional In Vitro Models Of The Intracellular Actin Cytoskeletal Network, Andrew Thomas Lombardo Jan 2018

Cargo Transport By Myosin Va Molecular Motors Within Three-Dimensional In Vitro Models Of The Intracellular Actin Cytoskeletal Network, Andrew Thomas Lombardo

Graduate College Dissertations and Theses

Intracellular cargo transport involves the movement of critical cellular components (e.g. vesicles, organelles, mRNA, chromosomes) along cytoskeletal tracks by tiny molecular motors. Myosin Va motors have been demonstrated to play a vital role in the transport of cargos destined for the cell membrane by navigating their cargos through the three-dimensional actin networks of the cell. Transport of cargo through these networks presents many challenges, including directional and physical obstacles which teams of myosin Va-bound to a single cargo must overcome. Specifically, myosin Va motors are presented with numerous actin-actin intersections and dense networks of filaments which can act as a …


Geochronologic Constraints On The Timing Of Metamorphism And Exhumation Of The Tillotson Peak Complex In Northern Vermont, Cheyne Aiken Jan 2018

Geochronologic Constraints On The Timing Of Metamorphism And Exhumation Of The Tillotson Peak Complex In Northern Vermont, Cheyne Aiken

Graduate College Dissertations and Theses

The Tillotson Peak Complex (TPC) in northern Vermont records high-pressure (HP) subduction zone metamorphism that occurred during the Ordovician Taconic Orogeny, and subsequent retrograde metamorphism and deformation that occurred during the Silurian Salinic Orogeny. Previous studies have documented a polymetamorphic history, with peak metamorphic pressures possibly up to 2.5 GPa and temperatures of 550°C. Prior to this research, constraints on the timing of metamorphism in the TPC were limited to a single Middle Ordovician 40Ar/39Ar total fusion age for glaucophane. This study integrates 40Ar/39Ar step heating analyses of multiple mineral phases and U-Pb dating of titanite with field and microstructural …


Spectroscopic Insight Into Oxidative Heme Cleavage By The Non-Canonical Heme Oxygenase Isdg From Staphylococcus Aureus, Matthew A. Conger Jan 2018

Spectroscopic Insight Into Oxidative Heme Cleavage By The Non-Canonical Heme Oxygenase Isdg From Staphylococcus Aureus, Matthew A. Conger

Graduate College Dissertations and Theses

IsdG and IsdI are non-canonical heme oxygenases (HO) from Staphylococcus aureus that catalyze the oxidative cleavage of heme to give novel organic products (staphylobilins) and iron as a nutrient for the pathogen. Comparison of the reported equilibrium dissociation constant (Kd) values for heme from IsdG and IsdI compared to the reported concentration of the labile heme pool called into question whether these enzymes are competent HOs in vivo. We took advantage of a second-sphere Trp whose fluorescence is quenched upon heme binding, which led to Kd values 2-3 orders of magnitude smaller than reported in the literature. Importantly, these Kd …


Improving Scalability Of Evolutionary Robotics With Reformulation, Anton Bernatskiy Jan 2018

Improving Scalability Of Evolutionary Robotics With Reformulation, Anton Bernatskiy

Graduate College Dissertations and Theses

Creating systems that can operate autonomously in complex environments is a challenge for contemporary engineering techniques. Automatic design methods offer a promising alternative, but so far they have not been able to produce agents that outperform manual designs. One such method is evolutionary robotics. It has been shown to be a robust and versatile tool for designing robots to perform simple tasks, but more challenging tasks at present remain out of reach of the method.

In this thesis I discuss and attack some problems underlying the scalability issues associated with the method. I present a new technique for evolving modular …


Soil Aggregates: The Mechanistic Link To Increased Dissolved Organic Carbon In Surface Waters?, Malayika Cincotta Jan 2018

Soil Aggregates: The Mechanistic Link To Increased Dissolved Organic Carbon In Surface Waters?, Malayika Cincotta

Graduate College Dissertations and Theses

Dissolved organic carbon (DOC) plays an important role in the global carbon (C) cycle because increases in aqueous C potentially contribute to rising atmospheric CO2 levels. Over the past few decades, headwater streams of the northern hemisphere have shown increased amounts of DOC coinciding with decreased acid deposition. Although the issue is widely discussed in the literature, a mechanistic link between precipitation composition and stream water DOC has not yet been proposed.

In this study, the breakup of soil aggregates is hypothesized as the mechanistic link between reduced acid deposition and DOC increases in surface waters. Specific hypotheses state that …


Regularization In Symbolic Regression By An Additional Fitness Objective, Ryan Grindle Jan 2018

Regularization In Symbolic Regression By An Additional Fitness Objective, Ryan Grindle

Graduate College Dissertations and Theses

Symbolic regression is a method for discovering functions that minimize error on a given dataset. It is of interest to prevent overfitting in symbolic regression. In this work, regularization of symbolic regression is attempted by incorporating an additional fitness objective. This new fitness objective is called Worst Neighbors (WN) score, which measures differences in approximate derivatives in the form of angles. To compute the Worst Neighbors score, place partition points between each pair of adjacent data points. For each pair of data points, compute the maximum angle between the line formed by the pair of data points and the lines …


Unprecedented Reactivity And Applications Of 1-Aza-2-Azoniaallene Salts, Ramya Srinivasan Jan 2018

Unprecedented Reactivity And Applications Of 1-Aza-2-Azoniaallene Salts, Ramya Srinivasan

Graduate College Dissertations and Theses

1-Aza-2-azoniaallene salts, derived by oxidation of substituted hydrazones, are highly reactive cationic heteroallenes. These species participate in several mechanistically distinct reactions including: (1) intramolecular [3+2] cycloadditions, (2) polar [4 +2] cycloadditions, (3) stereospecific C-H aminations, (4) electrophilic aromatic substitutions, and (5) chloroamination reactions. We have shown that this versatile reactivity is governed by the length of the tether and nature of the π-system.

A novel intramolecular electrophilic aromatic substitution reaction is observed when the tether length separating the 1-aza-2-azoniaallene salt and a pendant aryl ring is three methylene units to generate alkylaryl azo products. Variations in the electronics and sterics …


Microscale Controls On Lead Speciation In Soils: A Framework For Sustainable Remediation, Grant Reeder Jan 2018

Microscale Controls On Lead Speciation In Soils: A Framework For Sustainable Remediation, Grant Reeder

Graduate College Dissertations and Theses

The potential of a soil to immobilize heavy metal ions is dependent on the presence of adsorption sites, and the stability of metal species over the range of geochemical conditions present in the soil over time. Lead (Pb) is a cumulative toxin that is enriched in much of the urban pedosphere due to historical use of Pb-based paint and Pb-amended gasoline. Because in-situ remediation of Pb is possible if the bioavailable fraction can be rendered inert, understanding Pb-sorbent interactions is necessary to accurately and efficiently alter Pb speciation in soils. The objectives of this study are to 1) determine efficient …