Physical Sciences and Mathematics Commons^™

Optical Signatures Of Plankton In The Open Ocean: From Individual Cells To Global Patterns, Nils Haentjens

Electronic Theses and Dissertations

Marine plankton ecosystems play a major role on Earth, having implications for the global carbon cycle and the food-web structures. Ocean color satellites and networks of autonomous platforms equipped with optical sensors are the primary tools used to study phytoplankton dynamics. They provide long term records while offering a synoptic view of our oceans, enabling to study impact of climate variability on planktonic ecosystems. Interpretation of these observations rely heavily on optical theory and how light propagating through the water is affected by particles who absorb and scatter light (e.g. phytoplankton, sediments). However, the complexity of the optical properties of …

Fostering Coastal Destination Resilience In Maine: Understanding Climate Change Risks And Behaviors, Lydia Horne

Electronic Theses and Dissertations

Tourism is an increasingly important global industry. Coastal and nature-based tourism destinations are especially vulnerable to climate change. Trends in visitation are expected to shift under changing climate conditions, influencing tourist travel behaviors related to destination selection, timing of visits, and activity participation. Tourism suppliers’ adaptation and mitigation behaviors have the potential to alleviate negative shifts in visitation and respond to negative climate change impacts, while also enabling suppliers to take advantage of emerging opportunities. The purpose of this dissertation is to understand how tourism stakeholders, including tourism suppliers (i.e., business owners, managers) and consumers (i.e., visitors), perceive their risk …

Understanding Biomass Upgrading Through Hydrogenolysis Reactions: Kinetics And Mechanism, Jalal Tavana

Electronic Theses and Dissertations

This dissertation involves several hydrogenolysis reactions but is mainly focused on hydrodechlorination (HDC) of chlorobenzene (PhCl) and hydrodeoxygenation (HDO) of 2-furancarboxylic acid (FCA). Hydrodechlorination of PhCl has been the subject of research for some time. Here, we used a Pd/C catalyst to study this reaction though rigorous kinetics and mechanistic analyses in a CSTR reactor. The H₂/D₂ kinetic isotope effect (KIE) experiment revealed that H₂ is not involved in a rate controlling step. The kinetics data are in agreement with similar systems reported before and follow a first-order dependence on chlorobenzene, half order for hydrogen and …

An Intramolecular Method For The Formation Of Glycosidic Bonds, Sudeera Nadeeshani Kamburugamuwa Kamburugamuwe Loku Acharige

Electronic Theses and Dissertations

The improved understanding of carbohydrate functions in biological systems has increased the demand for well-characterized and pure carbohydrates in biomedical research. Chemical synthesis is the most feasible method to satisfy the scientific demand despite the inherent challenges of the glycosylation reaction. Therefore, it is essential to investigate novel methods for the formation of glycosidic bonds. In this work, an intramolecular method was developed using a thio-methylene-silyl linker to tether a glycosyl donor and acceptor. The glycosylation conditions resulted in the formation of both anomeric isomers with a preference for the inversion pathway, which is inconsistent with an entirely intermolecular glycosylation …

Live Cell Super-Resolution Microscopy Quanitifies An Interaction Between Influenza Hemagglutinin And Phosphatidylinositol 4,5-Bisphosphate, Jaqulin N. Wallace

Electronic Theses and Dissertations

Influenza virus, colloquially known as the flu, is an acute respiratory disease that infects several millions of individuals each year in the U.S. and kills tens of thousands of those infected. Yearly viral vaccines are widely available, however, due to the virus’s high mutation rate, their efficacy varies greatly. Due to the variability in vaccine efficiency against seasonal influenza, and the potential for even more pathogenic versions of influenza to emerge at any time, there is a high demand for a universal treatment option.

Influenza virus hijacks a variety of host cell components in order to replicate. The glycoprotein hemagglutinin …

Approximating Fol Ontologies Using Owl2, Robert W. Powell

Electronic Theses and Dissertations

With the amount of data collected everyday ever expanding, techniques which allow com- puters to semantically understand data are growing in importance. Ontologies are a tool to describe the relationships connecting data so that computers can correctly interpret and combine data from many sources. An ontology about water needs to describe what the term "river" may refer to: An arbitrary river or one usable for navigation; a single tributary or an entire river network; the riverbed or the water itself? Well-designed ontologies can be shared, reused, and extended across multiple applications and facilitate betters integration of different data collections.

Common …

A Synthesis Program: Reducing Uncertainties Of The Terrestrial Biosphere Carbon Cycle At Various Spatio Temporal Scales, Xinyuan Wei

Electronic Theses and Dissertations

The terrestrial biosphere plays an important role in the global carbon cycle, and disturbance fire and climate extreme drought have strong direct and indirect impacts on the carbon fluxes. In addition, the lateral dissolved organic carbon (DOC) flux from soils to inland waters represents an important component of the terrestrial biosphere carbon cycle.

Fires play an important role in the terrestrial biosphere carbon cycle, not only through direct carbon release but also contributing to a potential long-term storage as pyrogenic carbon (PyC). PyC is formed through fires, and because it may resist further biological and chemical degradation, is more stable …

Airborne Hyperspectral Data Application In Stress Detection Of Blueberry Fields And Ash Trees, Catherine Chan

Electronic Theses and Dissertations

Water management and irrigation practices are persistent challenges for many agricultural systems. Changing seasonal and weather patterns impose a greater need for understanding crop deficiencies and excesses (e.g. water, sunlight, nutrients) for optimal growth while allocating proper resources for prompt response. The wild blueberry industry is at heightened susceptibility due to its unique growing conditions and uncultivated nature. Early detection of stress in agricultural fields can prompt management responses to mitigate detrimental conditions including drought and disease. Remote sensing has provided timely and reliable information covering large spatial extents, while novel applications in hyperspectral data and imaging spectroscopy have shown …

Sulfur And Trace Metal Cycling At Convergent Margins, Jesse B. Walters

Electronic Theses and Dissertations

Subduction zones are the site of long-term chemical exchange between Earth’s surface and interior geochemical reservoirs. Subducting slabs are progressively depleted in volatiles and other mobile elements through dehydration and melting reactions. These elements are then introduced to the mantle wedge and volcanic arc. One consequence of this cycle is that volcanic arcs produce the most oxidized magmas on Earth. Sulfur, which exhibits a range in valence states from S^2- to S⁶⁺, is one of the few elements in the subducting slab capable of oxidizing the arc and mantle wedge. Sulfides in the slab may also act …

Variations In The Southern Hemisphere Westerlies Over The Last 23,000 Years From Lake Records In The Falkland Islands, Meghan M. Spoth

Electronic Theses and Dissertations

The Southern Hemisphere Westerlies (SHW) are an important driver of climate in the mid-latitudes of the Southern Hemisphere. Abrupt latitudinal migration of this coupled atmospheric-oceanic system is thought to be linked to the onset of the Termination at the end of the last ice age and to subsequent climatic variation through the late-glacial period and Holocene. However, the timing and spatial extent of these shifts, as well as variations in wind intensity, are poorly constrained, hindering our understanding of abrupt climate change in the Southern Hemisphere. In addition, future changes in the position and intensity of the SHW are a …

Biophysical And Stable Isotopic Profiles Of The Salmon Louse Lepeophtheirus Salmonis (Krøyer, 1837), Emma Taccardi

Electronic Theses and Dissertations

The salmon louse Lepeophtheirus salmonis is a parasitic copepod that infects wild and farmed salmonids throughout the northern hemisphere. L. salmonis represents the largest economic hurdle of the Atlantic salmon (Salmo salar) industry, with an estimated annual cost of nearly $1 billion globally due to production losses and anti-parasitic control measures. Salmon farming in Maine has existed for decades and is a critical economic driver, yet the region is underrepresented in global sea lice research. The aim of this work was to examine parasites in the context of animal trophic transfer and characterize physiological condition by quantifying the …

Investigations On The Helix-Coil Transition Inside Nanotubes, Dylan Suvlu

Electronic Theses and Dissertations

Proteins are the workhorses of biology and are essential to life as we know it. A protein’s function in the cell is intimately related to its three-dimensional structure. Thus, understanding structure formation in proteins has been an essential goal in molecular biology. Experiments indicate proteins start acquiring structure inside the ribosome—the cellular manufacturing plant of proteins—and the process is particularly important for membrane proteins. Therefore, the ribosome appears to play an active role in facilitating protein structure acquisition. However, how and when the ribosome accomplishes this task remains poorly understood. To better understand this process, we conducted molecular dynamics computer …

Understanding The Magnetic Properties Of Ii-Vi Semiconductor Nanocrystals, Alex Khammang

Electronic Theses and Dissertations

Semiconductor nanocrystals (NC) are well known for their unique size tunable optical properties making them suitable candidates for devices such as light emitting diodes (LEDs), solar cells, and cellular labels. II-VI semiconductors in the bulk form behave diamagnetically, but can inherit paramagnetic (PM) or ferromagnetic (FM) properties at the nanoscale. Reports suggest that the emergence of weak PM or FM behavior in undoped NCs are attributed to the increased surface to volume ratio compared for NCs. Traditionally, these NCs only obtain magnetic properties after doping with certain transition metals, such as Co, Mn, or Fe. Many mechanisms have been proposed …

Bicknell's Thrush Habitat Use On Commercial Forests In Maine, Usa, Kaitlyn Wilson

Electronic Theses and Dissertations

Forest reliant species may be significantly impacted by forest management practices. Understanding these impacts, and whether they are positive or negative, requires a species- specific understanding of habitat use. Bicknell’s thrush (Catharus bicknelli) is a range-restricted habitat specialist occurring in balsam fir (Abies balsamea) dominated montane forests that have been recently disturbed and are undergoing successional growth. While research investigating this species’ habitat use has been conducted throughout much of its breeding range, knowledge of Bicknell’s thrush habitat use in Maine is lacking. Greater understanding of habitat use in Maine would improve the ability of forest managers to promote conservation …

Fostering Climate Change Resilience: A Socio-Ecological Forest Systems Approach, Alyssa R. Soucy

Electronic Theses and Dissertations

As climate change continues to impact socio-ecological systems, those that rely on natural resources are highly sensitive to climatic changes. Maine’s forest industry provides for the economic and social well-being of many residents and is especially vulnerable to climate change impacts. Changes in growing season length and timing, forest health threats imposed by insects and pathogens, extreme weather events, shifting forest composition, and changes in natural disturbance severity and frequency have already begun, and are projected to continue, to impact forest systems in the Northeastern U.S. While climate change presents a threat to forest systems, opportunities also arise due to …

Extratropical Cyclones And Associated Climate Impacts In The Northeastern United States, Julia Simonson

Electronic Theses and Dissertations

There is growing concern that some aspects of severe weather could become more frequent and extreme across the northeastern United States (USNE) as a consequence of climate change. Extratropical cyclones and frontal systems are a common factor in a variety of severe weather hazards in the region. This dissertation examines three types of meteorological events impacting the USNE – ice storms, heavy rainfall, and high-wind events. The first research topic utilizes the Weather Research and Forecasting (WRF) model in a case study of the December 2013 New England ice storm. In this analysis, a series of tests are conducted to …

A Numerical Survey Of Multi-Planet Systems’ Inclination Excitation And Survival Under The Influence Of An Oblate, Tilted Star, Kathleen M T Schultz

Electronic Theses and Dissertations

Among the many exciting and thought-provoking discoveries facilitated by the Kepler telescope, one of the most puzzling is the very large proportion of systems with only a single transiting planet in them, relative to the number of systems with multiple transiting planets. Given that most of these multis are close together and have low mutual inclinations, and that planetary systems tend to form in such a configuration, the next logical step is to guess that at least some of the singles are part of multi-planet systems with large mutual inclinations between planets, excited by some other object’s gravitational perturbations. A …

A Method To Reclaim Multifractal Statistics From Saturated Images, Jeremy Juybari

Electronic Theses and Dissertations

The CompuMAINE lab has developed a patented computational cancer detection method utilizing the 2D Wavelet Transform Modulus Maxima (WTMM) method to help predict disrupted, tumor-associated breast tissue from mammography. The lab has a database of mammograms in which some of the image subregions contain artefacts which are excluded from the analysis, image saturation is one such artefact. To maximize statistical power in our clinical analyses, our goal is therefore to minimize the rejection of image subregions containing artefacts. The goal of this particular project is to explore the effects of image saturation on the resulting multifractal statistics from the 2D …

Examining The Northern Shrimp Fishery In A Changing Gulf Of Maine, Ashley N. Charleson

Electronic Theses and Dissertations

Northern Shrimp (Pandalus borealis) once supported a key commercial fishery in the State of Maine. Since its closure in 2013, the stock has remained in a particularly vulnerable state following recruitment failure, overfishing, and rising water temperatures. Furthermore, without this source of supplemental income, local fishermen have also experienced financial stress following unstable fishing conditions in other fisheries. The collective goal of this research project was to assess factors impacting the feasibility of reopening and maintaining this vulnerable winter fishery. These goals are addressed over 4 chapters. Chapter two offers insight regarding what is most often omitted from the regulatory …

Assessing The Factors That Alter Ecological Responses Of Cold, Oligotrophic Lakes To Nutrient Subsidies, Benjamin Burpee

Electronic Theses and Dissertations

Arctic and alpine areas experience rapid environmental changes that are altering nutrient delivery to lakes. I review the current state of lake ecosystem subsidization research and summarize Arctic and alpine lake subsidies, their ecological importance, and ways they are changing. I identify current knowledge gaps in Arctic and alpine lake subsidization research and highlight the importance of Arctic and alpine lakes for ecosystem subsidy research. Meltwater from the Greenland Ice Sheet (GrIS) exports sediment and nutrients to lakes, but the ecological effects of this subsidy remain unclear. To assess the effects, four glacially fed (GF) lakes that receive GrIS meltwater …

Phenolic Phytochemicals And Their Antioxidant Activities In Maine-Grown Asian, American-Hybrid, And European Plums, Hye Weon Hwang

Electronic Theses and Dissertations

Plum fruits of 16 plum cultivars derived from three species, Asian, American-hybrid, and European plums, and one cultivar of an interspecific hybrid between Asian plum and apricot were investigated to identify and quantify two major groups of phenolic phytochemicals, anthocyanins and hydroxycinnamic acids (HCAs) by HPLC–DAD/MS. The plums were harvested from 2014 to 2017. Some cultivars were analyzed through consecutive years to determine year-to-year differences and to evaluate the maturity impacts on the concentration of anthocyanins and HCAs from the partial-ripe stage and tree-ripe stage. Anthocyanins were present in red−purple colored plums, but their profiles varied among cultivars and species. …

Calculating Infinite Series Using Parseval's Identity, James R. Poulin

Electronic Theses and Dissertations

Parseval's identity is an equality from Fourier analysis that relates an infinite series over the integers to an integral over an interval, which can be used to evaluate the exact value of some classes of infinite series. We compute the exact value of the Riemann zeta function at the positive even integers using the identity, and then we use it to compute the exact value of an infinite series whose summand is a rational function summable over the integers.

First-Year Computer Science Students: Pathways And Perceptions In Introductory Computer Science Courses, Christina A. Leblanc

Electronic Theses and Dissertations

This study examined student perceptions and experiences of an introductory Computer Science course at the University of Maine; COS 125: Introduction to Problem Solving Using Computer Programs. It also explored the pathways that students pursue after taking COS 125, depending on their success in the course, and their motivation to persist. Through characterizing student populations and their performance in their first semester in the Computer Science program, they can be placed into one of three categories that explain their path; a “continuer” (passed COS 125 and decided to stay in the major), a “persister” (did not pass COS 125 and …

A Groundwater Flow Model To Aid In Water Resource Management For The Carraipia Basin In The Coastal Semi-Arid Region Of La Guajira State (Colombia), Efren D. Gomez Arevalo

Electronic Theses and Dissertations

About 160,000 inhabitants live in the 1,600 square kilometers Carraipia River Basin located in northeastern Colombia and northwestern Venezuela. Historically, water has been supplied to the inhabitants in this arid coastal region by shallow dug wells. Water supplied by these wells is frequently of poor quality due to high concentrations of total dissolved solids (TDS). Recently, due to the increasing demand for water, numerous deep wells have been drilled in the region to supply water to rural and urban areas from deep aquifers. Colombian agencies seek more quantitative information on groundwater resources, driven by increasingly severe water shortages over the …

Polysaccharide And Silver Nanoparticles Based Hydrogels, Porous Materials, And Sensors, Muhammad R. Hossen

Electronic Theses and Dissertations

Cellulose based hydrogels and porous materials are gaining significant attention across a wide range of applications due to the natural abundance, biodegradability and physicochemical tunability of this polysaccharide. Cellulose nanofibrils (CNF) outperform cellulose fibers in terms of physicochemical tunability since CNF possess relatively high surface area. However, superior dispersibility of CNF in aqueous phase makes it challenging for traditional methods to dewater CNF suspensions to fabricate robust hydrogels and porous materials. In this dissertation, a novel scalable capillary based method to dewater CNF suspensions is invented as well as CNF hydrogels and porous materials with a broad range of porosity …

Phytoplankton Community Composition In The Surface Ocean: Methods For Detection Using Optical Measurements, Pigment Concentrations, And Flow Cytometry, Alison P. Chase

Electronic Theses and Dissertations

Phytoplankton are microscopic photoautotrophs living in the surface ocean waters and help support all life on earth via photosynthetic production of oxygen. Thousands of species make up the bulk phytoplankton community, and the spatial and temporal distribution of different types of phytoplankton has relevance for many ocean ecosystem questions including marine food web dynamics, and carbon flux and sequestration. Methods to detect phytoplankton community composition (PCC) on the vast scale of the global ocean require estimates of PCC from remote platforms, namely earth-observing satellites. The use of satellite data to observe and interpret PCC in the surface ocean requires significant …

Gray Codes In Music Theory, Isaac L. Vaccaro

Electronic Theses and Dissertations

In the branch of Western music theory called serialism, it is desirable to construct chord progressions that use each chord in a chosen set exactly once. We view this problem through the scope of the mathematical theory of Gray codes, the notion of ordering a finite set X so that adjacent elements are related by an element of some specified set R of involutions in the permutation group of X. Using some basic results from the theory of permutation groups we translate the problem of finding Gray codes into the problem of finding Hamiltonian paths and cycles in a Schreier …

Quantification Of Interactions Between Influenza Hemagglutinin And Host Cell Phosphoinositides By Super-Resolution Microscopy, Matthew T. Parent

Electronic Theses and Dissertations

The influenza viral membrane protein hemagglutinin (HA) forms dense nanoscale clusters on host cell plasma membranes (PM), but the mechanisms that direct HA clustering are not well understood. Previous studies have observed HA associated with actin rich regions of the PM, but there are no known direct interactions between HA and actin. Phosphatidylinositol 4,5-biphosphate (PIP2) is a signaling lipid in the PM which can regulate the actin cytoskeleton, and actin comets initiated by PIP2 are known to be exploited by HA to reach the PM of infected cells. PIP2 is also used by other viruses, such as HIV and Ebola, …

Uav 6dof Simulation And Kalman Filter For Localizing Radioactive Sources, John G. Goulet

Electronic Theses and Dissertations

Unmanned Aerial Vehicles (UAVs) expand the available mission-space for a wide range of budgets. Using MATLAB, this project has developed a six degree of freedom (6DOF) simulation of UAV flight, an Extended Kalman Filter (EKF), and an algorithm for localizing radioactive sources using low-cost hardware. The EKF uses simulated low-cost instruments in an effort to estimate the UAV state throughout simulated flight.

The 6DOF simulates aerodynamics, physics, and controls throughout the flight and provides outputs for each time step. Additionally, the 6DOF simulation offers the ability to control UAV flight via preset waypoints or in realtime via keyboard input.

Using …

An Algorithm To Estimate Suspended Particulate Matter Concentrations And Associated Uncertainties From Remote Sensing Reflectance In Coastal Environments, Juliana Tavora

Electronic Theses and Dissertations

Suspended Particulate Matter (SPM) is a major constituent in coastal waters, involved in processes such as light attenuation, pollutant propagation, and waterways blockage. The spatial distribution of SPM is an indicator of deposition and erosion patterns in estuaries and coastal zones and a necessary input to estimate the material fluxes from the land through rivers to the sea. In-situ methods to estimate SPM provide limited spatial data in comparison to the coverage that can be obtained remotely. Ocean color remote sensing complements field measurements by providing estimates of the spatial distributions of surface SPM concentration in natural waters, with high …