Physical Sciences and Mathematics Commons^™

The Effects Of Biosolid Microplastics On The Microbial Community And Root Functioning In The Rhizosphere Of Soybean Crops In Agricultural Soil, Rebecca Chloe Lebel

Electronic Theses and Dissertations

Biosolids are semi-solid by-products from wastewater treatment plants where contaminants such as microplastics can accumulate, and transfer into the root zone causing ecotoxic effects to the rhizosphere microbial community. Furthermore, microplastics can alter soil properties which have a strong control on the size and diversity of the rhizosphere microbial community and its ability to consume root-borne carbon compounds. Using the MicroRESP system the respiration of the rhizosphere microbial community of soybeans subjected to microplastic biosolid mimics of two types (PET sheets and PPT beads) and two concentrations (2,000 vs 15,000 particles/kg dry soil) was quantified. Baseline respiration rates from extracted …

The Influence Of Spatiotemporal Variation In Food Web Models, Cecilia E. Heuvel

Electronic Theses and Dissertations

Aquatic ecosystems are constantly adapting to fluxes in season, temperature, nutrient cycling, and prey availability. Consequently, aquatic food webs are dynamic, and relationships between species are perpetually changing as organisms and primary producer communities adapt to current environmental conditions both in time and space. Despite this knowledge however, many food web studies continue to use temporally static and spatially homogenous representations of food webs. This thesis proposes that a detailed investigation of temporal and spatial trends in a large lake ecosystem can improve our understanding of the mechanisms and drivers of spatial and temporal variation in food web structure and …

Matches Made In Heaven Or Somewhere: Personalized Query Refinement Gold Standard Generation Using Transformers, Yogeswar Lakshmi Narayanan

Electronic Theses and Dissertations

The foremost means of information retrieval, search engines, have difficulty searching into knowledge repositories, e.g., the web, because they are not tailored to the users' differing information needs. User queries are, more often than not, under-specified or contain ambiguous terms that also retrieve irrelevant documents. Query refinement is the process of transforming users' queries into new refined versions without semantic drift to enhance the relevance of search results. Prior query refiners have been benchmarked on ad-hoc web retrieval datasets following weak assumptions that users' input queries improve gradually within a search session. Existing methods also have employed additional metadata, such …

Inference In Generalized Mean Reverting Processes, Yunhong Lyu

Electronic Theses and Dissertations

This dissertation proposes three types of processes that are suitable for modeling positive datasets with periodic behavior and mean-reverting level phenomenon. A class of generalized exponential Ornstein–Uhlenbeck process (GEOU) is consid- ered in Chapter 2. This chapter’s key characteristics include the following: first, the classical exponential Ornstein–Uhlenbeck process is generalized to the case where the drift coefficient is driven by a period function of time; second, as opposed to the results in recent literature, the dimension of the drift parameter is considered unknown. This chapter serves to weaken some assumptions, in recent literature, underlying the asymp- totic optimality of some …

Many-To-One: Transformer-Based Unsupervised Anomaly Detection And Localization On Industrial Images, Naga Jyothirmayee Dodda

Electronic Theses and Dissertations

Anomaly detection is of utmost importance in the realm of industrial defect identification, particularly when employing computer vision-based inspection mechanisms within quality control systems. This research introduces the Many-to-One (M2O) framework, which relies on a multi-level transformer encoder combined with a single transformer decoder, which forms many-to-one relation in the framework for detecting and localizing anomalies. The rise of Industry 4.0 and electric vehicles has increased interest in this area. Although previous research has made significant contributions, challenges still exist in this area. It is crucial to develop models that can generalize well and overcome time complexity problems that affect …

Developing New Strategies Towards The Fabrication Of Flexible, Organic Electronics, Daniella Skaf

Electronic Theses and Dissertations

An investigation into the use of greener dielectric and substrate materials, specifically shellac and paper, was done through the development of paper-based organic thin film transistors. Shellac and paper both hold advantageous properties that were explored in Chapter III, through the optimization in the fabrication of the devices and an evaluation of the electrical properties of these newly developed organic transistors. Different designs were explored using two common DPP-based polymers, P(DPP-T) and P(DPP-TVT), as the active materials, with Design #2 (bottom-gate top-contact) proving to be the best performing device according to the on/off ratio, charge mobilities and threshold voltage. Shellac …

Transmission Power Based Congestion Control Using Q-Learning Algorithm In Vehicular Ad Hoc Networks (Vanet), Pooja Chandrasekharan

Electronic Theses and Dissertations

To enhance road safety, Vehicular ad hoc networks (VANETs), an emerging wireless technology used for vehicle-to-vehicle and vehicle-to-infrastructure communication, are essential components to reduce road accidents and traffic congestion in Intelligent Transportation Systems (ITS). It also provides additional services to vehicles and their users. However, vehicles must balance awareness and congestion control in a dynamic environment to efficiently transmit basic safety messages (BSMs) and event-driven warnings. The limited channel capacity makes the reliable delivery of BSMs a challenging problem for VANETs. This paper aims to optimize the performance of VANETs by effectively managing channel load and reducing congestion by maintaining …

An Approach Of Lip Synchronization With Facial Expression Rendering For An Eca, Mohammed Maaz Mohammed Shoieb Khan

Electronic Theses and Dissertations

E-Tutoring systems have emerged as effective tools for remote learning and personalized education. However, to foster engaging and interactive experiences, there is a need to enhance the communication and expressiveness of virtual tutors within these systems. This research focuses on integrating facial expression animation and lip-syncing capabilities into an e-tutoring system, aiming to improve the realism and effectiveness of virtual tutor interactions. The study presents a novel approach to animating the facial expressions of the virtual tutor’s avatar using computer graphics, 3D animation, and computer vision techniques. Working with 3D files and using them to interpolate each face vertex are …

Electromagnetically Induced Transparency In An Ensemble Of Three-Level Lambda Systems, Sara Moezzi

Electronic Theses and Dissertations

Electromagnetically induced transparency (EIT) is a technique whereby a medium otherwise opaque to radiation of a particular frequency can be made transparent at that frequency by applying radiation of an appropriate second frequency. EIT demonstrates numerous current applications, with a notable focus on its utilization within the field of quantum information. Given the absence of an established theory of EIT in atomic ensembles, my primary focus is to develop theoretical models that describe both the quantum mechanical origin of EIT as well as the effect of interatomic interactions. In this thesis, I present two theoretical models of EIT in an …

Influence Of Lake Volume On Trophic Position, Carbon Use, And Resource Partitioning In Fish Across A Narrow Range Of Ecosystem Size, Alyssa Andersen

Electronic Theses and Dissertations

Lake size is an important factor governing seasonal variation in limnological phenomena, origin of nutrient sources, species interactions, cross-habitat linkages, and trophic pathways, all having complex influences on food web structure and function. Lake size effects are most clearly demonstrated across very wide gradients in surface area or volume. This approach incorporates several complicating and collinear elements such as changing fish assemblages and species richness, and therefore, incorporates additional but unaccounted shifts in food web structure and function. A comparison across a finer lake size gradient where fish assemblages and species richness change little or not at all is needed …

Using Harmonization To Examine Freshwater Mussel Species At Risk: A Sydenham River Watershed Case Study, Julia Ann Willsie

Electronic Theses and Dissertations

There are over 300 species of freshwater mussels (Family: Unionidae) across North America with many populations at risk or in decline. Mussels provide essential ecosystem services, yet they remain largely underexplored in terms of distribution, population sizes, life history traits, and co-existence with hosts, making species conservation efforts a challenge. To advance the conservation of freshwater mussel species at risk of extinction (SAR), this thesis aims to extend understanding of freshwater mussel SAR distributions in a biodiverse but vulnerable watershed in the Laurentian Great Lakes basin. This thesis asks: How can freshwater mussel SAR distribution data be leveraged through existing …

Area-Efficient Finite Field Multiplication Using Hybrid Set-Mos Technology, Chen Zhang

Electronic Theses and Dissertations

This work studies area-efficient implementation of bit-parallel binary polynomial multiplication and Karatsuba algorithm (KA), which have important applications in error control coding and network security, especially elliptic curve cryptography, among many other areas. All existing works in this respect are based on traditional CMOS technology. Research shows that new nanodevices such as single-electron transistors (SETs) can offer the great potential at device- and technology-level to further improve area cost in many digital applications (especially multiplication), thanks to their unique Coulomb oscillation characteristics. This thesis first proposes hybrid SET-MOS technology to design the XOR networks that are extensively used in polynomial …

Anomaly Detection In Large Datasets: A Case Study In Loan Defaults, Rayhaan Pirani

Electronic Theses and Dissertations

Given the rise in loan defaults, especially after the COVID-19 pandemic, it is necessary to predict if customers might default on a loan for risk management. This thesis proposes an early warning system architecture using anomaly detection based on the unbalanced nature of loan default data in the real world. Most customers do not default on their loans; only a tiny percentage do, resulting in an unbalanced dataset. We aim to evaluate potential anomaly detection methods for their suitability in handling unbalanced datasets. We conduct a comparative study on different anomaly detection approaches on four balanced and unbalanced datasets. We …

An End-To-End Hybrid Approach To Automatic And Semi-Automatic Image Annotation, Roisul Islam Rumi

Electronic Theses and Dissertations

This thesis presents a new end-to-end hybrid machine learning (ML) and deep learning (DL) approach for semi-automatic image annotation (SAIA) and automatic image annotation (AIA) in industrial assembly line setups. Image annotation refers to adding descriptive labels or tags to an image to provide information about the objects and features present in the image. On a high level, the proposed system uses the following steps to annotate images. The first step involves using an ML algorithm, Haar cascade, to split an image into smaller regions of interest (ROI) based on the object of interest, in our case, the connectors of …

Investigation Of Student Understanding Of Representations Of Probability Concepts In Quantum Mechanics, William D. Riihiluoma

Electronic Theses and Dissertations

The ability to relate physical concepts and phenomena to multiple mathematical representations—and to move fluidly between these representations—is a critical outcome expected of physics instruction. In upper-division quantum mechanics, students must work with multiple symbolic notations, including some that they have not previously encountered. Thus, developing the ability to generate and translate expressions in these notations is of great importance, and the extent to which students can relate these expressions to physical quantities and phenomena is crucial to understand.

To investigate student understanding of the expressions used in these notations and the ways they relate, clinical think-aloud interviews were conducted …

The Influence Of Framing And Recent Experience On Farmer Choices In Experimental Games Depicting Risk-Reducing Agricultural Technologies, Ana Maria Ospina Tobar

Electronic Theses and Dissertations

Climate change is a major threat to food security, particularly in low and middle-income countries that are highly dependent on staple crops for subsistence. The vulnerability of staple crops, like maize, in the face of climate change, is increasing due to the increasing frequency of droughts. This thesis aims to evaluate two mechanisms through which farmers may be more willing to adopt new technologies that increase their resilience to climate change: First, I evaluate the effectiveness of a new virtual maize farming game as a learning tool to teach farmers about the outcomes they could obtain under different weather events …

Accessible Autonomy: Exploring Inclusive Autonomous Vehicle Design And Interaction For People Who Are Blind And Visually Impaired, Paul D. S. Fink

Electronic Theses and Dissertations

Autonomous vehicles are poised to revolutionize independent travel for millions of people experiencing transportation-limiting visual impairments worldwide. However, the current trajectory of automotive technology is rife with roadblocks to accessible interaction and inclusion for this demographic. Inaccessible (visually dependent) interfaces and lack of information access throughout the trip are surmountable, yet nevertheless critical barriers to this potentially lifechanging technology. To address these challenges, the programmatic dissertation research presented here includes ten studies, three published papers, and three submitted papers in high impact outlets that together address accessibility across the complete trip of transportation. The first paper began with a thorough …

The Upper Ocean At The End Of An Ice Age: Using Proxies In Benthic Foraminifera To Investigate Intermediate Water Changes During The Last Glacial Termination, Cassandre R. Stirpe

Electronic Theses and Dissertations

The ocean is an important component of the global climate system and plays a key role as a storage reservoir for heat and carbon. Under glacial conditions, the ocean sequestered carbon from the atmosphere, contributing to a cooler global climate. During the last glacial termination, that carbon was released back into the atmosphere, but the exact timing and mechanisms of this transfer are still not fully understood. This study examines waters from the intermediate depths of the Southern Ocean to gain insight into deglacial processes. Intermediate waters are capable of reacting to climate change on decadal timescales, making them a …

Investigating Mercer's Paradox: A 10be Chronology Of Moraines Deposited During The Last Glaciation At Soda Lake, Wind River Range, Wyoming, U.S.A., Lauren M. Woods

Electronic Theses and Dissertations

Here I use geomorphic mapping and ¹⁰Be surface-exposure dating to address the paradox that lies within the general understanding of the mechanisms driving ice-age climate and glacial cycles. The long-standing and widely accepted Murphy-Milankovitch hypothesis suggests glacial cycles are controlled by the local intensity of summer-time insolation. By this hypothesis, glacier maxima should be achieved at times of low insolation intensity and asynchronously between the polar hemispheres, a pattern which is inconsistent with the glacial geomorphic record. The ¹⁰Be chronology I have constructed of moraines at Soda Lake, Wind River Range, Wyoming, U.S.A. shows nine glacial advances to …

Scaling Up The Relevance Of Land-Sea Connections In Coastal Bacteria Pollution Vulnerability, Bea E. Van Dam

Electronic Theses and Dissertations

Bacteria pollution closures of Maine’s coastal shellfish harvest areas have substantial negative consequences for coastal businesses and communities. Sustainability solutions for Maine’s shellfish harvesting areas and businesses require new types of knowledge and information to protect water quality and public health while avoiding unnecessary fishery closures. Coastal management agencies have interests in tools to support science-based management decision-making related to pollution and sustainability solutions for businesses and communities.

Prior research into land-sea connections has demonstrated uses of geographic information and statistical methods to facilitate management and science communication. Research in Maine has focused on identification and comparison of attributes influencing …

A Quantitative Visualization Tool For The Assessment Of Mammographic Risky Dense Tissue Types, Margaret R. Mccarthy

Electronic Theses and Dissertations

Breast cancer is the second most occurring cancer type and is ranked fifth in terms of mortality. X-ray mammography is the most common methodology of breast imaging and can show radiographic signs of cancer, such as masses and calcifcations. From these mammograms, radiologists can also assess breast density, which is a known cancer risk factor. However, since not all dense tissue is cancer-prone, we hypothesize that dense tissue can be segregated into healthy vs. risky subtypes. We propose that risky dense tissue is associated with tissue microenvironment disorganization, which can be quantified via a computational characterization of the whole breast …

A Vector-Valued Trace Formula For Finite Groups, Miles Chasek

Electronic Theses and Dissertations

We derive a trace formula that can be used to study representations of a finite group G induced from arbitrary representations of a subgroup Γ. We restrict our attention to finite-dimensional representations over the field of complex numbers. We consider some applications and examples of our trace formula, including a proof of the well-known Frobenius reciprocity theorem.

Wave Attenuation Through Submerged Oyster Aquaculture Cages, Liam T. Hanley

Electronic Theses and Dissertations

Coastal erosion presents a growing issue to shorelines around the world and is especially harmful to Maine, a region where sea-level rise is higher than the global average. Green and hybrid coastal defense strategies are being implemented around the country to provide sustainable, habitat-friendly solutions to erosion control. Maine is a hotspot for commercial aquaculture, with an estimated $13.6 million economic impact. This study looks to bridge the gap between Maine aquaculture and the living shorelines initiative, by determining the wave attenuating properties of submerged oyster cages. The project will be able to inform local oyster farmers, resource planners, and …

A Bi-Hemispheric Perspective On The Last Glacial Maximum And Termination Using 10be Surface-Exposure Chronologies From An Interhemispheric Asia-Zealandia Transect, Peter Strand

Electronic Theses and Dissertations

Late-Pleistocene glacial cycles represent the largest natural changes to Earth’s climate over the past one million years, and yet determining the underlying drivers remains a major mystery in paleoclimate. The observation of generally synchronous glaciation and deglaciation between the polar hemispheres (Mercer, 1984) runs contrary to long-standing ice age theory (e.g. Milankovitch, 1941), and was recently dubbed ‘Mercer’s Paradox’ (Denton et al., 2021). In this thesis I derive regional climate records from mountain glaciers along an interhemispheric Australasian transect, extending from the Mongolian Altai to the Southern Alps of New Zealand, to test the existence of Mercer’s Paradox in the …

Nanocellulose Based Foams For Low-Cost Disposable Medical Applications, Dominic Kugell

Electronic Theses and Dissertations

Polyurethane foams have been a staple material for their use in medical positioners, such as post-surgery elevation pillows as well as specific tailored positioners for their use during surgery. Polyurethane foams are preferred because of their lower cost compared to other petroleum derived foams, their versatility, and suitable mechanical properties. However, the environmental impact, including both cost and perception, of these foams is immense. Therefore, alternatives are being explored with biopolymers emerging as a promising class of materials. Cellulose is one such polymer that has recently demonstrated desirable properties. In this study, cellulose nanofibrils (CNF), a household foaming agent, and …

Collaborative And Engaged Research To Strengthen Equity And Adaptive Governance In Co-Managed Fisheries, Gabrielle V. Hillyer

Electronic Theses and Dissertations

Small-scale, co-managed fisheries are found throughout the world and often represent intertwining cultures, societies, communities, economies, institutions, and governments. They face complex issues, derived from ecological and social sources. Solving these issues requires diverse expertise, often developed through engaged methodologies which can facilitate collaborative solution creation between researchers, community members, and others. In this dissertation, I demonstrate the benefits of these engaged methodologies and review how they, when coupled with anticolonial approaches to research, can create more equitable solutions to complex issues. This dissertation focuses on multiple projects within the wild clam fishery in Maine including: (1) the creation of …

Longitudinal Case-Control Study Of Mammographic Breast Tissue Subtypes, Kendra Batchelder

Electronic Theses and Dissertations

Breast density is a known risk factor for breast cancer. However, there has been limited research on potential subtypes of mammographic dense breast tissue to identify areas of active dense tissue that is structurally reorganizing and links to cancer dynamics, versus areas of passive dense tissue which remains organized. We hypothesize that the amounts of subtypes of mammographic dense tissue and the associated rate of change through time could provide insights into breast cancer risk. A retrospective study was conducted to investigate breast cancer using longitudinal screening mammograms and accompanying pathology reports collected in 2015. Patients were matched by age …

Integrating Environmental Dna, Traditional Fisheries Techniques, And Species Distribution Modeling To Assess Bridle Shiner Status In Maine, Lara S. Katz

Electronic Theses and Dissertations

The bridle shiner (Notropis bifrenatus) is a small minnow species native to the eastern United States and southeastern Canada. The species is declining dramatically throughout most of its native range and has legal protection or concern status in thirteen states and two Canadian provinces. In Maine, the bridle shiner is listed as a Species of Special Concern and considered a Species of Greatest Conservation Need, partially because we lack a basic understanding of their status and distribution within the state. Bridle shiners have historically been found in southern and western Maine in densely vegetated, shallow habitats along the …

Electrochemistry, Oxidative Mediation, And Evaluation Of Medicinal Activity For A Series Of Triphenyl And Tri(2-Furyl) Phosphine Gold(I) Thiolate Complexes., Shyam Pokhrel

Electronic Theses and Dissertations

Gold(I) thiolate complexes have received a lot of interest in drug development due to their promising antiarthritic, antimicrobial, and antitumor properties. Among them, auranofin [(tetra-O-acetyl-D-glucopyranosyl)-thio(triethyl phosphine)-gold(I)] which was approved for the treatment of rheumatoid arthritis in 1985, is an important, medicinally active compound. Recently, researchers have focused on repurposing auranofin for other medicinal applications, as well as developing alternative phosphine gold(I) thiolate complexes for medicinal purposes.

This thesis presents the synthesis and characterization of a series of twelve phosphine gold(I) thiolate complexes of the general formula, R3PAuSR’ where R= phenyl or tri(2-furyl) and SR’ = (2-pyridyl thiol, 2, 2’-mercaptopyrimidine thiol, …

Expanding Glycomic Investigations Through Thiol-Derivatized Glycans, Robert Hurst

Electronic Theses and Dissertations

N-(2-thioethyl)-2-aminobenzamide (TEAB), a novel glycan auxiliary, was synthesized and its utility was evaluated. The auxiliary was conjugated to glycans by reductive amination with the water-stable reagent 2-picoline borane complex. Glycan products, which ranged from 1 to 7 linked hexoses, were all isolated in yields ranging from 60% to 90% after purification by reverse-phase chromatography. The novel conjugate introduces a convenient, shelf-stable thiol directly onto the desired free glycans with purification advantages and direct modification with efficient reactions through alkenes, halides, epoxides, disulfides, and carboxylates in yields of 49% to 93%. Subsequently, a thiol-selective modification of the BSA protein was used …