Now showing items 21-40 of 6824

    • InSAR-derived thermoelastic lava flow compaction following the 2014-2015 Holuhraun fissure eruption

      Fusso, Logan Alexander; Grapenthin, Ronni; Meyer, Franz; Webley, Peter (2022-08)
      The Icelandic volcano Bárðarbunga experienced a caldera collapse and a fissure eruption at Holuhraun from 16 August, 2014 to 27 February, 2015 (Sigmundsson et al., 2015). This eruption produced about 1.44 km³ of lava deposited over an 84 km² area on the Holuhraun plain north of the Vatnajokull Glacier (Pedersen et al., 2017), making it the second largest Icelandic eruption since the 1783-1784 Laki eruption (Gudmundsson et al., 2016). Since basaltic lava flows erupt at high temperatures (1100 to 1250 °C), they contract as they cool over time, which can manifest as measurable deformation of the lava flow surface. Remote sensing observations with high spatio-temporal resolution afford us with an opportunity to capture and analyze such post-eruptive processes. Here, we use Synthetic Aperture Radar (SAR) observations from 2015-2020 captured by the European Space Agency's Sentinel-I A/B satellite pair to perform Interferometric Synthetic Aperture Radar (InSAR) time series analysis on descending and ascending tracks that cover the Holuhraun lava field. Two Short Baseline Analysis (SBAS) are computed, and modeled deformation from plate tectonics and glacial isostatic adjustment is removed from these line-of-sight (LOS) velocity fields. We leverage the dual-view geometry of the estimated LOS InSAR velocity fields to infer effective vertical and east-west velocities of the lava flow surface. The effective vertical velocity field constrains a model linking lava flow compaction to cooling. The InSAR-inferred average velocities indicate higher rates of motion at lava tubes, eruptive centers, and "distributary centers" (as defined by Pedersen et al., 2017) where lava pooled before entering lava tubes during the eruption. We hypothesize that the different emplacement history of individual lobes and features of the lava field, as well as inconsistent compaction amounts of the Holuhraun alluvial plain, have caused the heterogenous cooling that manifests in a highly varying surface deformation field.
    • Intraspecific variation and the leaping ability of northern pike (Esox lucius): implications for invasion ecology and management

      Cubbage, Taylor L.; Falke, Jeffrey; Dunker, Kristine; Kappenman, Kevin; Westley, Peter (2022-08)
      Although biological invasions are a leading threat to global biodiversity they provide opportunities to study factors that mediate invasion success from ecological and evolutionary perspectives and inform management efforts. The invasion of Northern Pike (Esox lucius) throughout southcentral Alaska has provided a useful case study, where invasive Northern Pike may benefit relative to native individuals due to high habitat suitability, abundant fish prey, and adaptive or plastic selective forces of invasion. Northern Pike continue to spread throughout the highly interconnected river and lake systems of southcentral Alaska; however, hypothesized differences in Northern Pike and native salmonid leaping abilities make selective vertical drop barriers a potential management option. Here, I build upon previous work by comparing physiological and morphological traits of invasive and native Northern Pike from river and lake habitats in Alaska that may influence their invasion success and leaping ability. Then, I used leaping experiments to determine how physical (abiotic) factors and individual biological traits influenced the maximum leaping ability of Northern Pike and developed a model to characterize these relationships. I found that invasive Northern Pike stomachs were two times more likely to contain energy-rich vertebrate diet items relative to native individuals, which was associated with two-fold faster growth rates, earlier ages-at-maturity, and 30% greater lipid content. Diet and physiological benefits were greater in lake habitats for invasive individuals, while native individuals experienced improved metrics in river habitats, potentially explained by thermal regimes, metabolic demands, and food availability. Leaping experiments proved that Northern Pike could ascend barrier heights four-times greater than previously assumed; pool depth, body size, and standardized growth rate also influenced individual leap success. Northern Pike leaping ability was significantly lower than salmonids. However, model predictions suggest that faster growth rates of invasive Northern Pike in Alaska may marginally enhance their leaping ability, and barriers should be tested in-situ before implementation. Insights into Northern Pike physiology and leaping behavior that result from this work can help managers determine if Northern Pike-selective barriers are a viable option in southcentral Alaska and elsewhere Northern Pike are invasive, and supports the importance of intraspecific variation in invasive species ecology and management.
    • Human-polar bear interactions on the northern coast of Alaska

      Quigley, Gwendolyn; Brinkman, Todd J.; Wilson, Ryan; Reynolds, Arleigh (2022-08)
      Polar bears (Ursus maritimus) are sea ice-dependent marine mammals that, due to reductions in sea ice extent in the southern Beaufort Sea, are increasing their time spent on shore. Simultaneously, the anthropogenic footprint on the northern coast of Alaska is growing. As a result, human-polar bear interactions in this region are increasing. These interactions have the potential to be dangerous for humans, harmful to polar bears, and, therefore, require deliberate management. In this thesis, I examined two study systems that lacked the depth of knowledge necessary to craft defensible management plans. My research generated information regarding human-polar bear interactions that could be used to shape policy in the Arctic. In Chapter 1, I explored a dataset that documented human-polar bear interactions at a popular polar bear viewing area in Kaktovik, Alaska. My objectives were to determine what factors influence 1) polar bear displacement (temporary or permanent) from the viewing area and 2) human response (assertive or neutral) to an approaching bear. Using logistic regression, I determined that permanent polar bear displacement was more likely later in the observation season and when the bear's initial reaction to a human approach occurred as a greater distance. I also found that humans were more likely to act assertively towards a bear when food resources (i.e., whale bone pile) in the area were depleted. These behavioral patterns indicate that human and bear tolerance change over time and in relation to resource availability. In Chapter 2, I conducted the first systematic evaluation of polar bear behavioral response to overhead aircraft traffic. I conducted field sampling in a fixed-wing aircraft and observed polar bear response at varying altitudes. My goal was to intentionally elicit a behavioral response that, under the guidelines in the Marine Mammal Protection Act, would be considered biologically significant. My objectives were then to 1) predict when a polar bear would exhibit a biologically significant behavioral response and 2) estimate the probability of an aircraft eliciting a biologically significant response at different altitudes above the animal. Using linear regression and a hierarchical Bayesian approach, I found that bears were most likely to exhibit a biologically significant response when they were active prior to sampling, located on the mainland coast, and the aircraft approach altitude was less than 457m (1500ft). Furthermore, I found that the probability of eliciting a biologically significant behavioral response at a flight altitude of 30m (100ft) was 21.31% for an inactive bear on a barrier island and 61.46% for an active bear on the mainland coast. Together, these research efforts address pressing knowledge gaps related to polar bear behavior on the northern coast of Alaska. Information generated from this project can be used to inform management and reduce disturbance for polar bears in a changing Arctic.
    • Soundscapes on the Arctic Coastal Plain: assessing sound disturbance and the auditory sensitivity of caribou (Rangifer tarandus)

      Perra, Megan E.; Brinkman, Todd; Crimmins, Shawn; Mandel, Michael (2022-08)
      The Arctic Coastal Plain of Alaska is a region on traditional Inupiat land that supports millions of migratory birds and over half a million caribou (Rangifer tarandus) at the most critical time in their life-histories. They are an important part of seasonal subsistence activities for the surrounding rural Indigenous communities. Therefore, conservation efforts that support this ecosystem also bolster food security in the region. Monitoring this system has increasingly become a necessary and prudent task as the landscape evolves under the pressures of resource extraction and climate change. To date, limited research has been conducted on the sounds present in this environment (i.e., 'soundscape'). Monitoring sounds may help reveal the impact of these stressors and ecosystem-wide changes. There is also a need for researchers to evaluate what portion of the soundscape wildlife can actually hear, so we can better understand how soundscape change might affect them. I conducted two studies that apply soundscape monitoring and acoustic perception to the landscape and wildlife of the Arctic Coastal Plain. First, I evaluated the hearing thresholds of domestic Rangifer tarandus (reindeer) at the Large Animal Research Station at the University of Alaska Fairbanks in 2019 in order to help infer what anthropogenic sounds wild caribou may be sensitive to. Using Brainstem Auditory Evoked Response methods, I found that a caribou's auditory system can detect all forms of anthropogenic sounds that they might encounter on the Arctic Coastal Plain, including low frequency sounds associated with oil and gas exploration. Specifically, I found they can detect sounds as low as 30 Hz with great sensitivity, expanding the known lower limit of their auditory capabilities. This means that caribou may detect sounds of seismic exploration, gravel mine blasting and other anthropogenic sounds associated with resource extraction at a great distance, and may be more affected by these sounds than previously thought. From May through August of 2019, I used acoustic recording units stationed in a random grid across the Arctic Coastal Plain to passively monitor the soundscape study region-wide sound characteristics and their impact on vocal wildlife. Anthropogenic sound (i.e., anthrophony) is a pervasive and often overlooked consequence of land-use change, and something that has been relatively understudied in northern Alaska. For my soundscape research, I modeled the spatial and temporal distribution of anthrophony and bird vocalizations (i.e., biophony) across developed (Oilfields surrounding Prudhoe Bay), and undeveloped (Arctic National Wildlife Refuge) areas of the Arctic Coastal Plain. Hourly detections of anthrophony were not associated strongly with infrastructure but tended to increase as the season went on. Birds were more likely to vocalize in hours when anthrophony was present, and this effect was the strongest in the early season, during migratory bird arrival and breeding. Anthrophony's effect on the soundscape may alter biological cues that vocal and non-vocal migrants use to assess habitat patches, and fitness consequences will vary by species. Further research is needed to assess how bird communities and caribou movement respond to anthrophony.
    • Timing of flowering affects pollination and fruit set in Viburnum edule in boreal forests of Alaska

      Kornhauser, Kara L.; Mulder, Christa; Spellman, Katie; Carlson, Matthew; Wagner, Diane (2022-08)
      Spring flowering in Alaskan boreal forests is happening earlier on average; how this relates to the pollination of plants and their pollinator community is unknown. Highbush cranberry (Viburnum edule) is one of the first herbaceous understory plants to flower every year, and in years when it flowers early there are fewer other species in bloom compared to years when it flowers at a more average time. Highbush cranberry is also important as a subsistence food and many boreal animals consume these fruits as a regular part of their diet. The potential for change may lead to differences in the response of pollinators and plants under early season conditions which could alter resources for pollinators and impact fruit production. This research looks at the impact of flowering timing on pollen deposition on Viburnum edule, and the composition of the pollinator community visiting the available flowers. Using an experiment with flowers placed in boreal forest sites either at an early time or at a peak flowering time across two years, we found that early flowering highbush cranberry received fewer pollen grains than peak flowering highbush cranberry and were visited less. V. edule was primarily visited by syrphid flies, native bees, and muscoid flies. We also observed a lower total number of visitors, and a lower proportion of visitors that were bees during an early flowering time than at peak flowering time. Floral visitors were more abundant during the advanced flowering year than during an average flowering year. We do not currently think that pollen limitation is causing a reduction in fruit set of early flowering V. edule because at all flowering times observed, we found over 50% of flowers to have been presumed visited while less than half of flowers in an inflorescence form fruits on average. More information on boreal pollinators triggers for diapause break and floral visitation is necessary to make more reliable predictions of the future impacts of phenology shifts in flowering plants and insect pollinators.
    • Northern vistas: a retrospective of the rural Alaskan Volunteers in service to America program 1965-1971

      Hoefler, Carol Fuiten; Ehrlander, Mary F.; McCartney, Leslie; Wight, Philip (2022-08)
      This thesis examines the Volunteers in Service to America program as it operated in rural Alaska from 1965 to 1971. Oral histories, correspondence from the volunteers, trainers and stakeholders offer a rich historical perspective of the program's successes and failures. Remote and underdeveloped village conditions presented daunting operational challenges to the program and its volunteers. During the study period, rural Alaska underwent dramatic social and political changes as recent statehood and looming resource development necessitated resolution of Native land claims. A series of new federal anti-poverty initiatives and the transfer of existing agencies to state and local oversight presented opportunities for volunteer participation. From a national perspective, the program struggled as political tides shifted and conflicting ideologies impacted its mission. Through analysis of interviews and written accounts, this study raises questions about the volunteers' perceived mission as it relates to these rapidly changing conditions. It provides a lens for evaluation of the program's successes and failures. It recognizes the volunteers' efforts and reveals the serendipitous outcome of continued Alaskan civic participation from many of its original volunteers. This study highlights their efforts and demonstrates how the rural "VISTA Alaska" contributed to the development of a cohort of young professionals committed to lasting careers in service areas that have benefited rural Alaska and underserved populations.
    • Investigating impact of pulp density on flotation performance

      Dehghani, Fahimeh; Ghosh, Tathagata; Aggarwal, Srijan; Chen, Gang; Arya, Sampurna (2022-08)
      The Red Dog Mine, located in northwest Alaska, is one of the world's largest zinc/lead mines. The processing mill feed consists of a blend of ores from two different pits, namely, the Aqqaluk pit and the Qanaiyaq pit respectively. The mill circuit consists of grinding and multiple flotation circuits which separate zinc and lead minerals from their gangue contents depending on the interfacial tension between hydrophilic/hydrophobic mineral surfaces and their environment. The flotation circuit feed is characterized by high percent solids (~ 50%). Percent solids can potentially have a significant effect on the grade/recovery curve. Thus, it is very common that low-density slurries give better flotation response (high grades), particularly in flotation systems containing a significant amount of liberated hydrophilic unwanted mineral particles. Moreover, the blended feed is metallurgically complex and weathered, thus adversely affecting the performance of the mill. This project investigated the effects of pulp density on Red Dog flotation circuit performance and develop strategies to maximize recovery at 50% solids. Higher solids content increases the rheology of the slurry thereby causing turbulence and froth instability. To study the impacts of slurry density on flotation kinetics, a series of experiments were conducted by varying various operating and process parameters and assessing circuit optimization strategies. Initial batch tests performed on cyclone overflow samples showed that residence time, rotor revolution per minutes (RPM), and slurry density are important factors affecting flotation performance. Lower slurry densities usually lead to better kinetics. However, in the case of the initial tests, results indicated that slurry density has a minimal effect if residence time is increased. It was shown that yields as high as 73% with Lead (Pb) recovery values of 86.20% is possible even at 60% solids concentration by increasing the residence time. If the slurry is sufficiently diluted then higher rotor speeds combined with higher residence time would provide higher yields and recoveries. Initial results indicate that at lower RPM ranges, adequate residence time and higher slurry densities lead to better bubble loading and froth stability. Lead (Pb) and Zinc (Zn) recovery values of 89.42% and 80.33% were achieved at 20% solids and 1800 RPM rotor speed. Future test work includes investigation of froth stability and pulp phase kinetics, statistically, and designed programs to optimize flotation performance in high-density slurries. Several parameters including dosage, and type of collector, pH, the dosage of frother, dosage of depressant, the dosage of activator, type of grinding media, particle size, and bubble size were controlled in the optimization tests. The optimized condition was obtained for both galena, and sphalerite at different solid%. The locked cycle tests were designed based on the Red Dog flotation circuit. At the optimized condition, the grade, and recovery for solid 30% improved by around 0.5%. The optimized condition had a further impact on the flotation performance at a higher solid%. By increasing the solid%, the grade was improved by 1.84%, and 2.24% at galena concentrate for 40%, and 50%, respectively, compared to the normal condition. Recovery was improved for both solid% by less than 1%. The optimized condition increased Zn grade at the flotation circuit by 1%, and recovery by 4% for 40% of solid. In addition, the optimized condition increased grade at the flotation circuit by 5%, and recovery by 4% for 50% of solid.
    • Applying third-generation sequencing to pathogen surveillance and mixed infection detection

      Buttler, Jeremy B.; Drown, Devin M.; Bortz, Eric; Takebayashi, Naoki; Murphy, Molly (2022-08)
      One Health is the concept of interconnected health between plants, animals, humans, microorganisms and the environments they live in. One Health issues surround many important viral pathogens, including influenza, SARS-CoV-2, and Ebola, that have likely come from zoonotic spillovers. Genomic epidemiology combines pathogen genomes with metadata to forecast, track, and prepare for future pathogens and pathogen variants that may cause epidemics. Genomic epidemiology has been used to detect and track viral variants that have the potential to escape vaccines for viruses like porcine circovirus type 2 (PCV2). PCV2 causes porcine circovirus associated diseases (PCVAD), which results in weight loss and death in pigs around the world. The correlation between PCVAD and mixed infections shows that disease severity is linked to the microbial community in a host. Metagenomics allows researchers to sequence samples and sort out the individual community member genomes by bioinformatic analyses, allowing the study of the host microbiome. In this thesis, I tested if long read nanopore sequencing can uncover PCV2 diversity and reliably detect co-infections. I also assessed the accuracy and efficiency of long read metagenomic assemblers as a potential method for detecting mixed infections. In my first chapter, I found that nanopore sequencing can be used to understand PCV2 diversity and detect co-infections. This evidence shows that nanopore sequencing is a viable alternative to Sanger sequencing for PCV2 surveillance. In my second chapter, I found Flye built the most complete and accurate genomes for bacterial community members and their plasmids. Throughout my thesis I have shown that nanopore sequencing is a viable solution for modern surveillance. The lower cost of nanopore sequencing may allow more specific pathogen and metagenomic surveillance in regions with high risk of zoonotic spillovers, which may allow early detection of epidemic causing pathogens.
    • Developing a combined intake and exhaust vent for heat recovery ventilation in cold climates

      Bickford, Riley Joseph; Marsik, Tom; Peterson, Rorik; Dekenberger, David (2022-08)
      Heat recovery ventilation systems have become increasingly popular in modern residential buildings, particularly in cold climates. This has led to the research and development of supporting technologies, such as combined intake/exhaust vents. Conventionally, the intake and exhaust airflows of a heat recovery ventilation system use separate vents and penetrations in a building's envelope; combined intake/exhaust vents package these airflows together and use only one penetration. This simplifies heat recovery ventilation system installation and can lead to higher operating efficiencies; the implications are reduced up-front and operating costs as well as broadened access to heat recovery ventilation. Unfortunately, in cold climates, existing combined intake/exhaust vent designs are susceptible to frost accumulation, a mode of failure. The aim of this work was to develop a combined intake/exhaust vent more suitable for cold climate use: the Arctic Dual Hood. The design was developed in iterations informed by experimentation. These experiments included climate chamber evaluations and field performance comparisons. This design process produced a functional prototype with favorable frost mitigation characteristics compared to an existing combined intake/exhaust vent design, as determined through the field performance comparisons. Additionally, this prototype observed the constraints and met the performance requirements imposed by the American Society of Heating, Refrigeration, and Air-Conditioning Engineer's Standard 62.2: Ventilation and Acceptable Indoor Air Quality in Residential Buildings.
    • Look North Tokyo: Japanese business in post-World War II Alaska

      Bateman, Pierce A.; Ehrlander, Mary; Heaton, John; Coen, Ross (2022-08)
      Since the early 1950s, Alaska and Japan have engaged in both economic and cultural exchanges that have made lasting impacts on the 49th State. For the nearly 75-year-long relationship, Japan was Alaska's number one trade partner by the measure of its exports, worth at its height in 1992, well over $3 billion. From products like timber, fish, and natural gas, Alaska had the raw resources that Japan lacked, while Japan had the industrial economy that Alaska needed. Diminishing public and scholarly interest of Alaska-Japan relations, however, has resulted in the neglect of this recent period of Alaska's economic and diplomatic history. As such, this thesis asks: 1. How and why did Alaska's relationship with Japan develop and evolve over time? 2. In what ways did that relationship grow beyond its foundation in trade? 3. How did this relationship affect Alaska and what are its legacies? Using the Jack London Hypothesis of economic cycles, this thesis provides a history of Alaska-Japan relations and asserts that in periods of economic bust, when Alaska was forced to seek alternate streams of revenue, it actively pursued foreign trade with Japan, but that in times of economic boom Alaska neglected its relationship with Japan. During these periods of decreased attention to trade, however, the two partners sustained their relationship through the preexisting cultural, diplomatic, and business institutions that were built in the preceding boom period. Additionally, this research demonstrates that while Alaska's economic cycles drove its pursuit of international trade, Japan's receptiveness to these trade overtures also depended on its own waxing and waning economic conditions.
    • Alaska Earthquake Center Quarterly Technical Report July-September 2022

      Ruppert, Natalia (2022-11-10)
      This series of technical quarterly reports from the Alaska Earthquake Center (AEC) includes detailed summaries and updates on Alaska seismicity, the AEC seismic network and stations, field work, our social media presence, and lists publications and presentations by AEC staff. Multiple AEC staff members contribute to this report. It is issued in the following month after the completion of each quarter Q1: January-March, Q2: April-June, Q3: July-September, and Q4: October-December. The first report was published for January-March, 2021.
    • Some trends in non-native adaptation in villages along the Kobuk and Koyukuk Rivers in northwest Alaska

      Keim, Frank J. (1973-05)
      Non-Natives living in isolated village settings in Alaska have traditionally been Ignored in anthropological investigations. These non-Natives are the subject of this thesis. It is a preliminary treatment of the adjustments they must make as newcomers to a cultural environment that is at first unfamiliar to them. As a result of these adjustments ,• the newcomers develop a different approach to life, one which includes a blend of elements from both their own culture and that in which they find themselves as strangers. The thesis also briefly discusses these non-Natives as change agents in the modification of the life patterns of the Native people among whom they live. Finally, the thesis suggests tentative guidelines for the recruitment of bush personnel in Alaska.

      Zhang, Guohui; Yang, Hanyi; Yu, Hao; Li, Zhenning; Zou, Rong; Yuan, Runze; Ma, Tianwei (2022-09)
      This report documents the research activities to investigate the traffic crashes in Rural, Isolated, Tribal, or Indigenous (RITI) communities involving considerable incapacitating injuries and fatalities. The traffic crashes occurring in RITI communities, are different from urban traffic crashes, and are related more to the features like speeding, low application of safety devices (for instance, seatbelt), adverse weather conditions and lacking maintenance and repairs for road conditions, and inferior lighting conditions. Thus, it is necessary to study the properties and attributes of traffic crashes at the RITI area using data analysis methods, such as statistical methods, and data-driven methods. This project is trying to analyze the rural crash injury and fatality patterns caused by changing climates in RITI communities based on enhanced data analysis using latest mathematical method. The mixed logit model to examine the risk factors in determining driver injury severity in four crash configurations in two-vehicle rear-end crashes on state roads based on seven-years of data from the Washington State Department of Transportation. The differences between the MLM and the LCM are investigated for exploring the relationships between driver injury severity in the rain-related rural single-vehicle crash and its corresponding risk factors. Moreover, this project develops a latent class mixed logit model with temporal indicators to investigate highway single-vehicle crashes and the effects of significant contributing factors to driver injury severity. The results of this research will be beneficial to transportation agencies to propose effective methods to improve rural crash severities under special climate and weather conditions and minimize the rural crash risks and severities.
    • Western Ahtna Geographic Appendices during 2012-2014

      Kari, James; Smith, Gerad M. (2014-05)
    • The STEM trail: Alaska Native undergraduates find the right path in higher education

      Skinner, Olga J.; Leonard, Beth; Williams, Maria; Gilmore, Perry; Mercier, Ocean (2022-05)
      The goals of this research are twofold. (1) This research explores decision making and college experiences of Alaska Native undergraduates pursuing degrees in the science, technology, engineering, and mathematics (STEM) fields, and (2) this research, using participant observation explores the Indigenous metaphor of "the trail" to frame student persistence towards their degrees. Twelve participants, representing various STEM fields, Alaska Native cultures, and K12 schooling experiences, shared their motivations and aspirations through interviews and photographs. Key findings indicate the significant role that Indigenous Knowledge plays in influencing student decisions around majoring in STEM degrees. Findings also illuminate the variety of K12 STEM experiences and the influence on decisions to major in STEM. Awareness (ellangeq) and self-authorship as student development theory, also impact decision making. The use of "the trail" as a metaphor for persistence illustrates a strength-based model for persistence, that notes the importance of the individual and the role of the individual as a community member. This metaphor also displays aspects of preparation, finding the right path, obstacles, supports, and destinations. This metaphor also calls into question the role of the institution as students work to navigate the terrain towards their degrees.
    • Optimization and forecasting algorithms for converter dominated distribution networks using blockchain and AI

      Shah, Chinmay; Wies, Richard W.; Al-Badri, Maher; Huang, Daisy; Cicilio, Phylicia (2022-05)
      Integration of power electronic converter-based distributed energy resources (DERs) in electric power distribution networks is growing exponentially with the recent interest in reducing carbon emissions from fossil fuel-based generation. As the contribution of renewable energy sources in the DER mix continues to increase, so does the incorporation of battery energy storage systems and other controllable loads to compensate for the high variability and uncertainty in the generation from renewable DERs and grid demand. Strategies for increasing the contribution of renewable energy sources and using reserves to accommodate for variations and uncertainty in generation and load include distributed optimal power flow (OPF) methods and improved forecasting. This work proposes a co-optimization of power flow and flexibility reserves, executed on a private blockchain for security, solved using a parameterized deterministic method based on semi-distributed architecture and alternating direction method of multipliers (ADMM) based distributed architecture that addresses uncertainty and enhances the flexibility of the distribution network. However, ADMM guarantees convergence only for strictly convex problems and hence a relax-and-fix heuristic algorithm is proposed in co-ordination with ADMM to solve the OPF problem, which is non-convex in nature. Also, an accurate short-term load forecasting algorithm is essential to reduce the uncertainty in the dispatch results using the OPF algorithm. In this work, a short-term residential load forecasting algorithm is proposed using a two-stage stacked long short-term memory network-based recurrent neural network and Hampel filter to address this issue. All the proposed algorithms are tested using different case studies. Results demonstrate that the proposed algorithms reduce the impact of uncertainty in the distribution network, automate scheduling flexibility reserve and minimize its cost, reduce the OPF execution time using a distributed architecture, and produce residential load forecast with a significantly lower prediction error.
    • Marine debris in the Bering Sea: combining historical records, toxicology, and local knowledge to assess impacts and identify solutions

      Padula, Veronica M.; Beaudreau, Anne; Causey, Douglas; McDonnell, Andrew; Konar, Brenda; Hollmen, Tuula (2022-05)
      Marine debris, particularly plastic marine debris, has numerous impacts on the environment, wildlife, and human communities. This research examines dimensions of marine debris in the Bering Sea and Aleutian Islands, Alaska, including impacts of marine debris pollution on wildlife and the environment; the history of marine debris research, monitoring, and cleanup activities; and community perspectives on local to global solutions. The first chapter of this dissertation is an integrative literature review to better understand the current status of marine debris knowledge in the Bering Sea region and identify critical knowledge gaps. We synthesized the depth and breadth of research, monitoring, and cleanup activities to better understand the sources, prevalence, and impacts of marine debris on wildlife and coastal communities. Our review revealed several knowledge gaps, including two that were a focus of the final chapters of the dissertation: measuring the extent of plastic-associated contaminants in the Bering Sea and capturing community perspectives and concerns about marine debris in the Bering Sea. The second chapter examined variation in phthalates, a class of plastic-associated chemicals, in Aleutian Islands seabirds, to refine hypotheses regarding ecological and environmental factors that affect phthalate exposure in marine wildlife. We quantified phthalates in seabirds collected across >1700 km of the Aleutian Islands, Alaska, and measured six phthalate congeners in seabirds representing ten species and four feeding guilds. Phthalates were detected in 100% of specimens (n = 115) but varied among individuals (range 3.64 - 539.64 ng/g). Total phthalates did not vary geographically, but differed among feeding guilds, with significantly higher concentrations in diving plankton-feeders compared to others. Our findings suggest feeding behavior could influence exposure risk for seabirds and lend further evidence to the ubiquity of plastic pollutants in marine ecosystems. The final chapter of the dissertation explored perspectives and concerns of St. Paul Island community members regarding marine debris and plastic pollution. This component of the research aimed to catalyze the inclusion of local knowledge in marine debris solutions for St. Paul Island, Alaska, by documenting community members' perceptions of marine debris, including its origin, impacts, and proposed solutions. We interviewed thirty-six St. Paul Island community members from 2017 to 2020 about the types, amount, distribution, and impacts of marine debris they have observed on the island and its surrounding waters over recent decades. Research participants reported increases in plastic debris since the 1980s, particularly plastic bottles. Nearly 80% expressed concern about impacts to subsistence resources, including entanglement and ingestion of plastic particles by marine mammals and fishes. St. Paul Island community members' experiences highlight that solving the problem of marine debris cannot rely on local efforts alone but requires broader policies and mitigation strategies to address the sources of debris and advance environmental justice for coastal communities. Overall, this dissertation contributes an improved understanding of the social and ecological impacts of plastic pollution in the Bering Sea region and the potential science and policy solutions that can stem the tide of marine debris.
    • Seeing the forest through the trees: how site conditions mediate white and black spruce responses to climate in Interior Alaska

      Nicklen, E. Fleur; Ruess, Roger W.; Roland, Carl A.; McGuire, A. David; Lloyd, Andrea H. (2022-05)
      The boreal forest provides essential ecosystem services and helps regulate global climate. With climate change occurring at a faster rate at high latitudes, including in the boreal forest biome, it is critical to understand how boreal forests are responding to these unprecedented changes. Despite much effort, uncertainty remains as to how boreal forest productivity has and will change with ongoing climate changes. Some of the uncertainty reflects the complex mosaic of regional climatic patterns, direct and indirect species-specific responses to regional climate, and heterogenous local site conditions that affect boreal forest productivity. I focused on the latter uncertainty: the potential role of topographic, edaphic, and biotic conditions in mediating the climate-growth responses of boreal tree species. My overarching goal was to quantify the radial growth response of black spruce (Picea mariana) and white spruce (Picea glauca), the two most common tree species in interior Alaska, to climate variability across a suite of site conditions to better understand the observed and predicted variation in climate driven productivity across a variable landscape. I employed a systematic sampling design to quantify the landscape-scale patterns in both environmental conditions and incremental annual growth of trees distributed across a 1.28 million-ha study area in Denali National Park and Preserve (and beyond in Chapter 4). I also used targeted sampling of carbon isotopes in tree rings to investigate potential drought stress. I found that near-surface permafrost, slope angle, and elevation strongly modified the magnitude, shape, and, in some cases, the direction of radial growth response of both species. For white spruce, the negative growth response to warm and dry summer conditions intensified in high competition stands and in areas receiving high potential solar radiation. During years with high cone and seed production, white spruce shifted its current year's carbon resources from radial growth to reproduction and showed signs of drought stress. I also observed differences between black and white spruce climate-growth responses, with near-surface permafrost driving their contrasting responses to June-July temperatures and with black spruce growth showing an overall more positive response to summer precipitation. These results demonstrate that local site and stand variables can force contrasting growth responses to similar climate conditions and help predict how future black and white spruce growth may play out with climate changes across a heterogeneous landscape. My results underscore the pivotal role of near surface permafrost in both the climate-growth responses and competitive dynamics of black and white spruce. Consequently, my results emphasize the importance of ongoing and predicted changes in the distribution and prevalence of permafrost for the future of the boreal forest.
    • The linguistic dreamstate: Freud, Lacan, and intertextuality in Samuel Beckett's The Unnamable

      Kay, Michael R.; Coffman, Chris; Holt, Joseph; Carr, Richard; Brightwell, Gerri (2022-05)
      This thesis focuses on the process of symbolization and signification in Samuel Beckett's novel, The Unnamable. The introduction presents readers with important and relevant critical interpretations of the novel, primarily those that are focused on the self, the use of language, and psychoanalytic theory. Then, the thesis introduces readers to key concepts in semiotic and psychoanalytic criticism, such as that of the signifier, sign, big-O Other, and the Lacanian Imaginary, Symbolic, and Real, by applying these concepts to a reading of The Unnamable. The next section, "The Linguistic Dreamstate," argues that the novel's narrator occupies a state tangential to consciousness, subconsciousness, and unconsciousness. In occupying this state, one that is outside of physical reality, the narrator is confronted with a language he does not understand and, while speaking, seeks to understand what he has previously said, mirroring the process of psychoanalysis as it concerns the meaning of dreams. Finally, it is shown that the narrator attempts to use language to as a means to stop using language. In so doing, the narrator illustrates the inability of language (and the Symbolic) to reconstruct the Real, and the innate desire for the Real (or objet a) even in those who do not have a reality within which they see the lack of the Real.
    • Snow as structural habitat for wolverines in a changing Arctic

      Glass, Thomas Rutherford Winder; Kielland, Knut; Breed, Greg; Williams, Cory; Robards, Martin (2022-05)
      Arctic snowpack provides critical wintertime habitat for animals to facilitate thermoregulation and avoid predators. Wolverines (Gulo gulo) are iconic among such animals, relying on snow burrows for resting sites and reproductive dens. Most of the knowledge regarding this mesocarnivore's association with snow, however, has so far originated in more southerly latitudes. In this dissertation, I investigated Arctic wolverines' behaviors associated with snow, focusing on how specific snow properties influence resting, habitat selection, and avoiding predators. Motivated by the paucity of published descriptions of wolverine resting burrows and reproductive dens on tundra, I first described terrain features and architecture of such sites. I found that resting burrows typically consist of a single tunnel leading to a resting chamber, sometimes associated with non-snow structure such as stream cutbanks and river shelf ice. By contrast, reproductive dens typically consist of longer tunnels associated with snowdrift-forming terrain. Second, I used GPS collar data from 21 adult wolverines, coupled with snowpack information at 10 meter pixel resolution, to evaluate wolverine habitat selection and movement response to snow depth, density, and melt status. I found that wolverines select deeper, denser snow, except when snow is melting, likely reflecting resting site use. Third, I developed a machine learning model to classify wolverine behaviors using tri-axial accelerometers based on direct observations of three captive wolverines, and applied this model to free-living wolverines in Arctic Alaska. I found that the model performs better when allowed to predict behaviors as "unknown," and that it accurately predicts resting, food handling, running, and scanning surroundings. Finally, based in part on this classification model, I evaluated the extent to which wolverines' use of snow burrows and surface beds for resting sites is influenced by thermoregulatory needs versus predation avoidance. I found evidence in support of both demands driving resting behavior; wolverines trade thermoregulation off against predation avoidance by resting on the snow surface on warm, sunny days, but use snow burrows on cold, dark days to meet both demands simultaneously. Collectively, this dissertation demonstrates the importance of Arctic snowpack to wolverines, a topic of increasing importance as the snow season shortens with climate change, and serves as a model for investigating behavioral processes associated with snow among other species.