Now showing items 21-40 of 10176

    • Breeding biology of storm-petrels at Wooded Islands, Alaska

      Quinlan, Susan E. (1979-12)
      Fork-tailed and Leach’s Storm-Petrels were studied at Wooded Islands, Alaska, 59°52‘ N, 147°25’W, to document and compare their breeding biology. Measurements of both species from California to the Aleutian Islands showed clinal variation; current subspecies divisions are not justified. Fork-tailed Storm-Petrels nested in a wider variety of habitats, arrived earlier at night, nested earlier, and fledged young in a shorter period than Leach’s Storm-Petrels, apparently because of their different oceanic distributions. River otter predation was the major cause of nest failures. Nesting success was higher within an exclosure than in areas exposed to predation. Predation was greater at low than high nest densities, and greater in soil than in rock habitat. Continued otter predation may decimate soil-nesting populations. Fork-tailed Storm-Petrel chick growth patterns did not vary between habitats, or nest densities. Mid- and late hatched fork-tail chicks grew faster, attained heavier weights, and had shorter nestling periods than early hatched chicks.
    • Vetting model and satellite-based estimates of regional scale carbon exchange at northern high latitudes using solar-viewing infrared spectroscopy

      Jacobs, Nicole; Simpson, William R.; Euskirchen, Eugénie S.; Guerard, Jennifer; Maxwell, David A. (2021-08)
      Carbon exchange in the Boreal Forest and its response to a warming climate is a critical process that needs to be understood for more accurate predictions of climate change. Therefore, we established a ground-based long-term monitoring site at the University of Alaska Fairbanks in Fairbanks, Alaska, USA (64.859°N, 147.850°W) operating a solar-viewing Bruker EM27/SUN Fourier transform infrared spectrometer (FTS). This instrument measures vertically integrated column abundances of carbon dioxide (CO₂), methane (CH₄), and carbon monoxide (CO), termed Xgas, i.e., XCO₂. These measurements are directly comparable to satellite-based measurements, for which these ground-based observations provide validation data. Measurements of XCO₂ and XCH₄ have to be extremely precise because variability in atmospheric columns of CO₂ and CH₄ is often less than 1% of the background levels of these long-lived gases. Therefore, the observations in Fairbanks were carefully vetted through comparisons of results from two retrieval algorithms applied to the same observed spectra, comparisons of observations from two EM27/SUN FTS operating side-byside, and comparisons between an EM27/SUN FTS and measurements from a Bruker IFS125HR in the Total Carbon Column Observing Network (TCCON) at Caltech, Pasadena, California. These data are all collected over a period of about 4.5 years. Comparisons of retrieval methods indicate that the results are tightly correlated, but there are offsets that could be corrected with an appropriate scaling factor. Observed biases between two colocated EM27/SUN FTS were in agreement within instrument precision. Biases between the EM27/SUN and TCCON retrievals at Caltech are larger and more variable than biases between the two EM27/SUN FTS in Fairbanks, which may be partially explained by differences in spectral resolution. These biases are also similar to those reported in previous studies. Vetted Fairbanks observations are used in combination with those from two TCCON sites in the Boreal Forest, East Trout Lake, Saskatchewan, Canada (54.354°N, 104.987°W) and Sodankylä, Finland (67.367°N, 26.631°E), to evaluate quality control methods and bias in XCO₂ from the NASA Orbiting Carbon Observatory 2 (OCO-2). This study yielded alternative quality control thresholds and bias correction, tailored to Boreal Forest regions that allow for increased data throughput and reduced seasonality in bias over northern high latitude regions. In particular, increased data throughput in spring and autumn months made it possible to measure XCO₂ seasonal cycles using satellite-based measurements. In this analysis, we found that the Asian Boreal Forest region stood out as having the largest seasonal amplitude and earliest seasonal drawdown of any region. There is also a pronounced west-to-east gradient of increasing seasonal amplitude and earlier seasonal drawdown across the Eurasian continent. Comparisons with two independent global CO₂ models are good, showing high correlation and spatial agreement. Analysis of modeled (GEOS-Chem) surface contact tracer contributions reveals that the largest seasonal amplitudes occur in regions that have the largest contributions from land-based surface contact tracers with 15 or 30 day atmospheric lifetimes, suggesting that accumulations of CO₂ exchanges during atmospheric transport on approximately monthly timescales play an important role in shaping observed XCO₂ seasonal cycles in northern high latitude regions. Furthermore, surface contact tracer contributions from land were more correlated with XCO₂ seasonal amplitude than estimates of total annual fluxes or seasonal amplitudes of flux estimates within a region, emphasizing the importance of understanding the effects of atmospheric transport when interpreting observations of XCO₂.
    • On estimating rotor noise generated by small unmanned multirotors

      Holst, Brian; Peterson, Rorik; Chen, Cheng-fu; Hatfield, Michael (2021-08)
      Unmanned aerial vehicles are utilized for missions ranging from wildlife surveillance to delivery of commercial goods. Previous research at the Alaska Center for Unmanned Aircraft Systems Integration (ACUASI) at the University of Alaska Fairbanks has focused on the monitoring of different species of wildlife, and some of this research was conducted utilizing multirotors. This work presents an introductory investigation and analysis of the acoustic noise generated by a single 15-inch rotor and applies this noise model to multiple rotors on a multirotor. The rotor is analyzed utilizing semi-empirical calculations and this work presents the process to continue acoustic analysis through simulation and analytical computation. Although this work studies, specifically, the 1555MR propeller designed by Advanced Precision Composites Propellers, the semi-empirical equations can be applied to other rotor designs. By investigating the analytical process, this work also presents a potential route through theory to identify the sound produced by these multirotors. The flow solution requires computational fluid dynamics software to output the flow on and around the rotors; this output can then be used for the analysis of noise. The total noise generated in stable hover is considered with certain assumptions about the blade geometry and aircraft motion. This work is organized into four chapters that detail the background, motivation, theory, setup, methods, results and conclusion. By utilizing this work and the works cited, readers and the researchers at ACUASI should understand the theory and be able to reproduce the results herein. With the estimation of noise of these multirotors, ACUASI will be able to refine their wildlife monitoring missions to ensure the observed animals are less affected by the noise generated by these vehicles.
    • Applicability of the Walder-Hallet frost fracture model to laboratory cyclic uni- and bi-direction freeze-thaw of limestone and sandstone

      Haas, Abram; Peterson, Rorik; Kim, Sunwoo; Zhang, Lei (2021-08)
      Due to changing climate conditions, new geographic areas are being impacted by diurnal and seasonal freezing and thawing conditions. Many geologic materials in far north latitude areas, that had not undergone significant freeze and thaw previously, are now expected to experience those conditions more often. The bedrock in these northern regions is often used as the foundation for many buildings and other infrastructure, and so it is extremely important to understand the integrity of this material with the changing conditions. Walder and Hallet created a theoretical model to analyze the temperature of fine cracks within a rock when subjected to freezing conditions, and the growth of fine cracks due to thermally-induced water migration followed by freezing. More recently, Dr. Murton conducted multiple cyclic unidirectional and bidirectional freeze-thaw experiments in the laboratory that simulated active layer rocks both with and without permafrost below. These experiments measured temperature and pore pressure of the rock, and monitored the formation and growth of macroscopic (i.e. observable) cracks. Using Walder and Hallet's model as a starting point, I have created a numerical model to analyze the cyclic fluctuating temperature conditions used by Murton in his experimental work, but is not accounted for in the original Walder and Hallet model. I then compared his laboratory results with the numerical model predictions of temperature and location of observable crack growth. This required adjusting some model parameters used by Walder and Hallet to correspond with the experimental conditions and geological materials used. I found that the model predicts the correct location of maximum cracking, and the time of observable crack growth, for the unidirectional experiments. However, it predicted nearly the opposite of the laboratory results for the bidirectional experiments. To obtain these numerical results, I had to adjust parameters that attempt to describe the flow resistance within a fine-grained freezing rock material; a difficult and little understood phenomenon. Future work should focus on improving some of the original model assumptions that do not apply to most experimental situations including those of Murton. These include the angle of cracks, and the potential interaction between adjacent cracks. While the results of this numerical model did not predict all the observed results of Murton's experiments, it has shown what portions of the numerical model appear to work correctly, and what assumptions from the original theoretical model by Walder and Hallet need to be adjusted and improved.
    • Antibiotic resistance in a changing North: unearthing the effects of disturbance-induced permafrost thaw on the Alaskan soil resistome

      Haan, Tracie J.; Drown, Devin M.; Podlutsky, Andrej; Hueffer, Karsten; Burkhead, Jason (2021-08)
      The evolution of antibiotic resistance in pathogenic bacteria is a major threat at the forefront of public health today. By studying soils, one of the ancestral origins of antibiotic production and resistance, we can gain insight into how antibiotic resistance genes (ARGs) from the environment have contributed to the evolution and emergence of resistance in pathogens. These studies are particularly important in soils where polar amplification and human expansion has already impacted the frequency and intensity of soil disturbance events (e.g., wildfires, deglaciation, land-use). In Alaska these disturbances augment permafrost thaw shifting the biogeochemical properties of active layer soils that structure microbial community composition and hypothetically the resistome (i.e., summation of ARGs). Thus, the goal of this thesis was to assess how soil disturbance, and the subsequent shift in community composition, will affect the types, abundance, and mobility of ARGs that comprise the subarctic soil resistome. In the first chapter I cultured bacteria from a permafrost thaw gradient in Interior Alaska, tested the isolates for susceptibility to antibiotics, annotated their genomes for ARGs, and compared their resistance profiles to a global database of soil bacteria genomes. I found that phylogenic and ecological factors structured the resistome. Additionally, antibiotic resistance phenotypes and genotypes were widespread in the soil isolates suggesting resistance is an intrinsic component of bacterial evolution. In the second chapter, I used long read metagenomics to identify predominant ARGs, ARG host taxa, and the relationship between community composition and ARG abundance. From the long read data, I unearthed major trends in the types of ARGs at our study site and determined ARG abundance had a quadratic relationship with disturbance and negative relationship temporally by year highlighting the complex interplay soil conditions have in structuring the taxa that enrich ARGs in the community. To analyze how individual bacteria contribute to ARGs in the community, I generated metagenome assembled genomes (MAGs) using Hi-C proximity ligation. From the MAGs, I found a significant difference in ARGs per genome between phyla that emphasized how an enrichment of specific bacteria can affect the abundance of ARGs in subarctic soils. I also identified several plasmid-borne ARGs highlighting the potential for horizontal gene transfer. Overall, this thesis provides evidence that ARGs in permafrost-associated soil are structured by disturbance-induced community shifts. Thus, as climate change increases t the frequency of disturbance events that shift the microbial communities in active layer soils, One Health can be impacted by alterations to ARGs comprising the resistome.
    • Habitat use of spectacled eider broods in relation to salinity and food availability on the Yukon-Kuskokwim Delta, Alaska

      Graff, Nathan R.; Lindberg, Mark; Hollmén, Tuula; Knut, Kielland (2021-08)
      Spectacled eiders (Somateria fischeri) nest and raise their broods in coastal areas of the Yukon-Kuskokwim Delta, which may be vulnerable to projected climate change effects of increased temperatures, storms, and sea level rise. These changes in turn will likely affect wetland salinity levels used by ducklings, which are a potential constraint to growth and survival of young ducklings while their salt glands develop. To examine this potential concern, I investigated spatial and temporal pond salinity dynamics, food availability, and habitat use of spectacled eider broods at Kigigak Island, AK during 2011-2012. I found that salinity was highly variable across the island, ranging from 0-23.9 ppt and averaged 4.9-12.9 ppt in ponds at brood observation sites during the first 30 days of brood rearing. Salinity typically increased through the summer across all habitat types, but at the highest rate in high sedge habitat. The most common invertebrate taxonomic groups included Eurytemora, Harpacticoida, Annelida, and Chironomidae, which were found in nearly all ponds sampled with salinity ranging from 0.7- 16.1 ppt. Neither salinity nor invertebrate abundance explained pond foraging use by broods. Additionally, I used robust design occupancy models to estimate brood foraging patterns. Pond occupancy ranged from 0.43-0.59 between years. Overall, brood use of ponds was not dictated by salinity levels or invertebrates present, suggesting that most ponds provide suitable brood rearing habitat. I did not detect any obvious constraint to pond use within brood rearing habitat under the environmental conditions encountered.
    • Bridging expert knowledge and fisheries data to inform assessment and management of rockfishes in the Gulf of Alaska

      Gordon, Jesse; Beaudrau, Anne; Carothers, Courtney; Williams, Benjamin (2021-08)
      Over the past few decades, nearshore rockfishes (Sebastes spp.) have experienced increased pressure from multiple fisheries throughout the Gulf of Alaska. The unique life history traits of rockfishes pose a host of challenges that make them difficult to monitor and vulnerable to overfishing. Rockfishes are economically and culturally important to coastal communities in the Gulf of Alaska. Therefore, the inclusion of fishers' knowledge in rockfish assessment and management will help to address biological goals and meet the needs of a growing fishery. This thesis examines the recent history and current management issues in nearshore rockfish fisheries in the Gulf of Alaska through triangulation of expert knowledge, fishery data, and biological surveys. We conducted semi-structured interviews with 43 fishers and agency staff who have long-term knowledge of and experience in rockfish fisheries within the Sitka and Kodiak areas. Chapter One presents a synthesis of changes in commercial and recreational rockfish fisheries since the 1970s, based on datasets from the Alaska Department of Fish and Game (ADF&G) and expert knowledge from interviews. Harvest data indicated both increases and decreases in nearshore fishing effort and harvest patterns, depending on the fishery sector, region, and rockfish species. Fishers and agency staff offered a longer-term and contextual understanding of changes in rockfish abundance. Most experts observed an overall decline in pelagic rockfishes near Sitka, AK and more variable patterns of abundance near Kodiak, AK. While many experts were hopeful about future sustainability of rockfish fisheries, others expressed concern about increases in localized fishing pressure, growth of charter fishing, barriers to access in some fisheries, and declines in rockfish biomass. Chapter Two identified institutional pathways and gaps in public engagement with rockfish fisheries management in Alaska. Fishers and agency staff highlighted the value of formal and informal institutions for effective engagement and emphasized the importance of relationship building and trust between fishers and agency staff. Fishers demonstrated stewardship over their fisheries through participation in local to state management processes, establishing norms of sustainability within fishing associations, and by taking personal actions to promote fishery conservation. Experts identified institutional gaps which included transparency issues regarding regulations, underrepresentation of recreational and subsistence harvesters in the Board of Fisheries public process, and communication barriers between the sport and commercial divisions of ADF&G. Our findings highlight the challenges of bringing together disparate data sources and the benefits of including multiple ways of knowing to produce a more complete understanding of dynamic fishery systems.
    • Modeling supraglacial lake drainage and its effects on the seasonal evolution of the subglacial drainage system in a tributary glacier setting

      Franco, Nevil Arley; Truffer, Martin; Wackerbauer, Renate; Delamere, Peter (2021-08)
      This work aims to gain a better understanding of the relationship between glacier motion and water distributed through subglacial drainage systems. A numerical scheme (GlaDS) is used to model both inefficient and efficient drainage systems to see which dominates after the draining of a supraglacial lake on a synthetic glacier that is made up of an outline that features a main branch and a tributary. The geometry is based on the surgetype Black Rapids Glacier (Ahtna Athabascan name: Da lu'itsaa'den) in Alaska, where a lake develops in the higher ablation zone, and drains rapidly early in the melt season. It has also been observed that this lake drainage causes a twofold or threefold speed-up of the main branch, with some acceleration of the lower-lying Loket tributary. This speed-up can be considered a surrogate for a surge, which also initiates in the main branch, while, during times of quiescence, the ice flow on the tributary is dominant. We investigate the effects of varying timing and volume inputs of lake drainage with a focus on its effects beneath the tributary. We find that the response of the glacier depends on the seasonal timing, the amount of water from the draining lake, and its location on or near the margins of the glacier. Results show that an inefficient drainage system is the cause of the glacier speed-up, both when the lake drains rapidly or when there is an extended time in drainage, at any time of the season. The speed signals vary throughout the glacier depending on the location of the lake relative to that of an evolved efficient drainage system.
    • Enhancing tumor antigen presentation with complement targeted liposomes

      Francian, Alexandra; Kullberg, Max; Kuhn, Thomas; Burkhead, Jason; Knall, Cindy (2021-08)
      Tumor-mediated immune evasion and suppression can be prohibitive to successful cancer treatment and recovery. A defining trait of cancer progression is when tumor cells develop the ability to evade detection by the immune system. Advanced tumors can suppress the presentation of antigens to effector immune cells by secreting regulatory cytokines and by downregulating the expression of major histocompatibility complex I (MHC I) receptors on the surface of tumor cells. Effective anti-tumor immunity requires the processing and persistent presentation of tumor antigens to effector cells. The cells responsible for this are antigen presenting cells (APCs), which initiate the immune response against cancer by engulfing and presenting tumor antigens to effector immune cells. APCs present tumor antigens, which provide specific targets for helper T cells and cytotoxic T lymphocytes, allowing the immune system to distinguish cancer cells from noncancerous cells. There are many different types of tumor antigens, and the increased effort to sequence reactive epitopes and establish a database makes tumor antigen immunotherapy a promising avenue for treatments and vaccines. Immunotherapies have been developed to restore the immune response against tumors without the toxic side effects of chemotherapeutic drugs. This research describes a promising cancer immunotherapy utilizing a liposome nanoparticle that binds to endogenous complement C3 proteins in serum and is internalized by APCs through the complement C3 receptor, resulting in direct delivery of encapsulated compounds. APCs were shown to internalize C3-bound liposomes containing ovalbumin (OVA), a model antigen, resulting in a significant increase in activated T cells that recognize OVA, reduced tumor growth in all mice (n=5), and complete elimination of both treated and distal tumors in two out of five mice (40%). Blood from treated mice had lower percentages of immunosuppressive cells, higher percentages of B cells, and increased anti-OVA IgG1. Collectively, treatment with OVA C3-liposomes is able to induce the activation of both cell-mediated and humoral immune responses. C3-liposomes encapsulating a melanoma tumor antigen, TRP-2, were able to reduce and eliminate established tumors in a melanoma tumor model in 6 out 7 mice (86%), with the addition of checkpoint blockade, anti-CTLA-4, improving the results (tumor reduction in all mice; n=3). C3-liposomes were also able to induce expression of costimulatory molecules and the production of proinflammatory cytokines and factors in targeted APCs. These results indicate that C3-liposome delivery of tumor antigens to APCs initiates a potent and systemic antitumor immune response.
    • A sled dog model for positive health effects of weight management and exercise

      Falkenstein, Laura Kay; Dunlap, Kriya; Coker, Robert; Jerome, Scott (2021-08)
      Hypertrophic white adipose tissue found in obesity leads to chronic inflammation and reduced insulin sensitivity, bringing rise to a myriad of diseases and is a significant risk factor for premature death. Obesity can be combatted with physical activity, dietary restrictions, or a combination of the two. However, exercise training regardless of changes in body weight has been shown to improve metabolic health. Expanding on a previous study of changes in metabolic biomarkers upon weight gain and after a period of athletic conditioning, in this project we used a sled dog model to examine biomarker shifts over a course of sedentary weight gain, exercise training without weight loss, and exercise training accompanied by weight loss. In order to examine the benefits of exercise training both with and without weight loss, a cohort of healthy sled dogs each served as their own controls as we observed changes in metabolic indices in conjunction with moderate body weight gain, exercise training while sustaining the higher body weight, and exercise training with weight loss.We focused on indices specifically linked to type II diabetes - an obesity-linked disease affecting more than 10% of American adults. Biomarkers measured include plasma glucose, glucose transporter 4, insulin, and hemoglobin A1c. We also measured inflammatory cytokines tumor necrosis factor alpha and interleukin 6, as well as hormones leptin, adiponectin, and resistin. Many biomarkers measured produced not significant change or fell outside of our standard concentrations, but plasma glucose, glucose transporter 4, and tumor necrosis factor alpha produced intriguing results. Weight gain increased plasma glucose while exercise training increased glucose transporter 4 present on peripheral blood mononuclear cells. The changes we observed to plasma glucose, glucose transporter 4 and tumor necrosis factor alpha may be indicative of reduced insulin sensitivity with exercise and weight loss. We believe this may be the result of the high energy demand of exercise training coupled with low caloric availability.
    • The politics of penguin pleasure: why animal sexualities matter to humans

      Emanuel, Nicole; Schell, Jennifer; Heyne, Eric (2021-08)
      This thesis is about what it means to think with penguins. It explores the ways in which we form ideas about these animals, and how those ideas can impact our beliefs about our own lives, penguins' lives, and the kinds of relationships that exist among humans and non-humans. It includes a survey of penguin representations across media and culture, particularly focusing on children's television and movies, nature documentaries, and non-fiction accounts of polar travel. While these penguin-centric texts can vary strikingly in tone, the penguins themselves appear again and again in an appealing light. Across a wide range of time and media, penguins are frequently portrayed as spunky, determined, and battling incredible odds to survive. That popular image of the plucky penguin has lent itself surprisingly well to debates about the naturalness of same-sex parenting in human society. The film The March of the Penguins (which was embraced by conservative Christians for its depiction of "traditional family values") and the picture book And Tango Makes Three (about two male chinstrap penguins who managed to successfully hatch an egg together at the Central Park Zoo) illustrate two sides of these public conversations. As the close reading and theoretical analysis performed in this thesis indicate, both views fail to truly understand penguins as living, courting, mating, reproducing beings. The behaviors of these actual animals are far too complex and varied to reduce to an alignment with either side of this fight over human concepts and morals.
    • Neuroendocrine and glial cell remodeling in a hibernating mammal

      Duncan, Cassandra; Williams, Cory; O'Brien, Kristin; Christian, Helen (2021-08)
      In most seasonally breeding vertebrates, changes in photoperiod trigger the remodeling of neuroendocrine and glial cells known to be involved in activation of the reproductive axis. We used electron microscopy to determine whether similar remodeling occurs under conditions of continuous darkness during hibernation in arctic ground squirrels (Urocitellus parryii). Immediately prior to the reproductive season, arctic ground squirrels naturally sequester themselves in a persistently dark hibernacula for 6-8 months where they experience only muted fluctuations in ambient temperature. Hibernation consists of two to three week-long bouts of torpor, during which body temperature and metabolism are depressed, periodically interrupted by short (<24h) interbout arousals where animals become euthermic and metabolism returns to "normal" levels. Although their exact functions are unknown, interbout arousals are generally thought to be associated with homeostatic processes. With the exception of brief dynamic changes during interbout arousals, brain activity and neuroendocrine pathways are generally thought to be relatively static across hibernation. We hypothesized that interbout arousals may allow for cellular ultrastructural remodeling of pars tuberalis thyrotroph cells, hypothalamic tanycytes, and pars distalis gonadotroph cells across hibernation, allowing for animals to activate their reproductive axis in anticipation of the active season. To test this, we sampled brains from arctic ground squirrels during early, mid-, and late hibernation, as well as post hibernation. We found evidence for cellular remodeling and activation of the reproductive axis across hibernation including decreases in neuronal contacts with the hypothalamic basal lamina, increases in the cell area and decreases in granule density of pars distalis gonadotrophs, increases in gonadal mass, and upregulation of steroidogenic genes in gonadal tissue. We hypothesize that the return to euthermy during interbout arousals allows for remodeling of the hypothalamus and pituitary, which we tested by exposing male arctic ground squirrels to a warm ambient temperature (30°C) during midhibernation, which causes animals to prematurely end hibernation. However, the premature termination of hibernation resulted in limited ultrastructural changes, suggesting that temperature alone is insufficient to activate reproductive maturation. Altogether, our study reveals a previously underappreciated physiological dynamism during hibernation that allows animals to rapidly transition between seemingly incongruous life-history states.
    • Understanding the outcomes focused management production process: meta-analysis of the relationship between activities, settings, and the benefits of recreation participation

      Diamond, Kimberly; Fix, Peter J.; Peterson, Jen; Coker, Robert (2021-08)
      The 1958 Outdoor Recreation Resources Review Commission, through a 1962 report, tasked federal agencies to inventory supply and demand for outdoor recreation participation. Recreation managers are progressively focusing on demand for the beneficial outcomes of recreation, but have struggled to structure planning and management models to guide decisions that optimize recreationists' ability to attain desired benefits. The Outcomes Focused Management (OFM) framework links benefits to specific activity and setting combinations, giving managers a functional role in the process of benefit production. Past studies examining the OFM's activity-setting-benefit relationship reported weak results, but suggest activity is a stronger predictor of benefit attainment than setting. A better understanding of how activity and setting inputs affect recreationists' ability to realize desired benefits is needed for continued implementation of OFM, with the aim of improving attainment rates of positive recreation outcomes. This study used meta-analytic techniques with data compiled from 16 OFM studies to replicate and expand on published work. With the goal of improving the activity-setting-benefit model, this study introduced two predictor variables, previous visitation and visitors' residential proximity to the site, controlled for the desirability of the benefit, and re-conceptualized the setting variable by testing whether study site is a better predictor of benefit attainment than different settings within a site. Two-way analysis of variance tests measured the dependence of 40 personal (PER) and household, community, economic, environmental benefits (HCEE) on activity participation and setting, using effect sizes and significance levels to compare seven models. This meta-analysis reciprocated findings of a 2004 study, failing to offer definitive evidence of linkages among recreation opportunities in the context of the models tested. Benefit items exhibiting relatively higher sensitivity to activity and setting inputs were 1) "Restore my body from fatigue" (PER), 2) "Improved respect for privately owned lands" (HCEE), 3) "Increased self-confidence" (PER), and 4) "Greater respect for private property and local lifestyles" (PER). Suggestions for future OFM studies and research on the activity-setting-benefit relationship are made, in addition to a summary of potential implications for OFM based on the findings of this study.
    • Experimental investigation of polymer induced fouling of heater tubes in the first-ever polymer flood pilot on Alaska North Slope

      Dhaliwal, Anshul; Dandekar, Abhijit; Zhang, Yin; Goering, Douglas J. (2021-08)
      Mineral fouling in heat exchangers has been extensively investigated by researchers in recent times. The oil and gas industry has a long history of fouling issues in production systems as a result of produced fluids treatment. Due to decline in production rates in oilfields new technologies are being developed and field tested in pilots. Polymer flooding is one such technology that involves addition of polymers to injection fluids to enhance oil production. A polymer flood pilot has been set up in the Schrader Bluff viscous oil reservoir at Milne Point field on the Alaska North Slope (ANS). The results from the pilot are encouraging, however a major concern of the operator is the influence of polymer on the production system after breakthrough, especially the fouling in heat exchangers. This study investigates the propensity of polymer fouling on the heater tubes as a function of different variables, with the ultimate goal of determining safe and efficient operating conditions. This work applies a multi-experimental approach to study the severity of polymer-induced fouling in both dynamic and static states of produced fluids as well as studying the stability of polymer solutions at different temperatures. A unique experimental setup was designed and developed in-house to simulate the fouling process on the heating tube. The influence of heating tube skin temperature, tube material, and polymer concentration on fouling tendency was investigated. Each test was run five times with the same tube, and in each run, the freshly prepared synthetic brine and polymer solution was heated from 77°F to 122°F to mimic field-operating conditions. The heating time and fouling amount were recorded for each run. Dynamic Scale Loop (DSL) tests were conducted to study fouling due to polymer at different temperatures (165°F to 350°F) in a dynamic state of fluid flow where the fluids mimic the residence time of fluids in the heat exchanger on the field pilot. Cloud point measurement has also been conducted to find the critical temperature at which the polymer in solution becomes unstable and precipitates out. The morphology and composition of the deposit samples were analyzed by environmental scanning electron microscopy (ESEM) and X-ray diffraction (XRD), respectively. It was found that the presence of polymer in produced fluids would aggravate the fouling issues on both carbon steel and stainless-steel surfaces at all tested skin temperatures. Only higher skin temperatures of 250°F and 350°F could cause polymer-induced fouling issues on the copper tube surface, and the fouling tendency increased with polymer concentration. At the lower skin temperatures of 165°F, no polymer-induced fouling was identified on the copper tube. A critical temperature that is related to the cloud point of the polymer solution was believed to exist, below which polymer-induced fouling would not occur, and only mineral scale was deposited but above which the polymer would aggravate the fouling issue. The cloud point of the tested polymer solution was determined to be between 220°F and 230°F. In the DSL tests it was found that at higher skin temperatures of 250°F and 350°F tube blocking was observed in the DSL tests whereas the tests at 165°F and 200°F did not show any tube blocking in the same time period. These experiments also manifested the influence of cloud point of the solution as deposit rate increased significantly in both carbon steel and stainless-steel tubes when the skin temperature was higher than the solution cloud point. The results of this study have provided guidance to the operator for the field-operations.
    • The catalyst for contemporary jihad: the religious leaders and their strategies

      DeWitt, Ronnie; Duke, Rob; Skya, Walter; Sine, Don; Botros, Maged; Boylan, Brandon (2021-08)
      This dissertation provides insight in the methodologies utilized by leaders of jihadist terrorist organizations who create a dedicated following in their pursuit of establishing a global caliphate. The research in this project illustrates a linkage from these charismatic leaders to the sacred edicts of the Koran, the Hadith, the Sunna, Sharia (Islamic jurisprudence), and the prophet Muhammad. Moreover, it bears out a unique perspective in academic national security studies which delves deeper than similar published works regarding subject matter focused on both violent and stealth jihad (also known as the non-violent usurpation of non-Islamic cultures). These subjects are discussed in detail with real-world examples that focus on the surreptitious use of political propaganda and sustaining influence, which are key ingredients necessary to recruit empathetic followers into doing the bidding of Islamic-based terrorist organizations. Without studying the psychological aspect that motivates potential terrorists it would be a daunting task to develop countermeasures in defeating this global threat. This dissertation also reviews key literature related to this concept. This investigative study bears out a perspective that uniquely differs from any previously published work in this discipline due to the author's professional experience outside of academic research. This will become clear in chapter seven which focuses upon the infamous Day of Terror trial in the Southern District of New York Federal Court in 1995. This episode, coupled with other evidence, will prove that jihadists have been striving to establish a global Islamist caliphate by utilizing terrorism and cultural usurpation.
    • Human paleoecology from the late glacial to early holocene, Tangle Lakes, Alaska

      Darcy, Audra J.; Reuther, Joshua D.; Bigelow, Nancy H.; Clark, Jamie L. (2021-08)
      This study examines paleoenvironmental change from the Late Glacial to the Early Holocene in the Tangle Lakes region of interior Alaska to explore changes in resource distribution and impacts on prehistoric hunter-gatherer subsistence patterns in upland settings (>500 masl). In interior Alaska, prehistoric hunter-gatherer subsistence economies were organized around the procurement of large herbivores (bison, caribou, elk, and moose), which were primarily regulated by habitat availability. Changes in habitat availability altered the distribution of key faunal resources, necessitating shifts in land-use strategies. The palaeoecological record from Glacier Gap helps contextualize resource distribution within dynamic landscapes by identifying changes in habitat availability for grazing, mixed-feeding (bison, caribou, elk), and browsing (moose) herbivores. This study applies pollen analysis, as well as carbon and nitrogen isotope analysis, of lake and peat deposits to reconstruct paleoenvironmental change from ~14,000 to ~6,000 Cal yr. BP. Results indicate grazing habitats persisted until approximately ~13,500 Cal yr. BP, which allowed for initial expansions of bison and elk, but habitats became mixed following the appearance of birch shrubs. Existing archaeological data indicate that initial use of upland regions coincided with expansion of bison and elk habitat, which would have represented large-bodied, predictable sources of food. As shrubs continued to expand, grazing and browsing habitats became increasingly fragmented in a mixed-feeding period between ~13,000 to ~10,000 Cal yr. BP. Fragmentation of bison and elk habitats made these species less predictable on the landscape, which likely led to the abandonment of the Tangle Lakes. A shift from mixed-feeding to browsing habitats occurred following the Holocene Thermal Maximum at ~10,000 Cal yr. BP with increasing shrub growth and the expansion of peat, supporting caribou and moose populations. Settlement patterns indicate re-occupation of the Tangle Lakes, and intensified use of uplands, when browsing specialists became more predictable, and subsistence focus shifted to the procurement of caribou ~6,000 Cal yr. BP. Taken together, grazing and browsing habitats represent homogeneous environments where resources were more abundant and predictable for hunter-gatherers, while mixed-feeding habitats represent heterogeneous environments where herbivores were fragmented and less abundant or predictable on the landscape.
    • Health benefits of the hunter/gatherer lifestyle

      Coker, Melynda Sheri; Greenberg, Joshua; Brinkman, Todd; Duffy, Lawrence; Lindberg, Mark (2021-08)
      The Hunter/Gatherer Lifestyle has long been associated with positive health benefits. I measured specific metabolic parameters associated with this lifestyle, highlighting lean tissue preservation. Severe loss of lean tissue mass (LTM) (sarcopenia) is a progressive, multifactorial disease presenting with decreased functional performance, age-related bone loss, increased falls and fractures, obesity, type II diabetes mellitus, depression, hospitalization, and even mortality. Degradation of LTM, often accompanied with obesity, is cost-prohibitive emotionally, physically, and financially. To counteract LTM deterioration, a positive net protein balance (NB) must be created through increased protein synthesis or suppressed protein breakdown. I utilized isotope tracer infusion methodology to compare equivalent serving sizes of wild, freerange red meat (FR) to grain-fed commercial meat (CB) on human NB. I observed that FR elicited significantly higher NB than CB due to greater suppression of protein breakdown. I next asked if an unscripted 8-12-day Alaska expeditionary backcountry hunt (ABEH) for moose, caribou, and sheep hunters would be executed in negative energy balance and positively influence metabolic markers while maintaining LTM. I found that energy expenditure was far greater than intake and contributed to reductions in body weight, adipose tissue, serum lipids, and intrahepatic lipid, while preserving LTM. Finally, I asked if a proprietary drink with a unique amino acid formulation (EMR) similar to FR could elicit fat loss and LTM maintenance in a cohort unlikely to gain access to FR. EMR or Optifast® was provided once per day to obese, elderly individuals. With no additional manipulations and in one month, there was a net gain of thigh muscle cross-sectional area and significant reductions in total and visceral fat mass. Concluding, I sought specific metabolic outcomes derived from distinct aspects of the understudied hunter/gatherer lifestyle (i.e., FR, ABEH, EMR). I found positive influences on health which would contribute to LTM preservation during aging, decreasing individual, family, and societal burdens linked to loss of LTM. These findings provide increased emotional, physical, and financial value to the hunter/gatherer lifestyle.
    • Current and novel tools in the health assessment of large whales

      Cates, Kelly Ann; Atkinson, Shannon; Bejder, Lars; Cunningham, Curry; Mueter, Franz; Straley, Janice (2021-08)
      Alaskan marine ecosystems are undergoing unprecedented change and species are facing increasingly variable and potentially inhospitable habitats. As top predators, marine mammals serve an important role as sentinels of ecosystem health. With their high site fidelity, abundant numbers, coastal presence and role as a top predator, humpback whales (Megaptera novaeangliae) provide a meaningful view into current ecosystem conditions and processes. In order to tap into their usefulness as bioindicators the basic physiology of humpback whales needs to be understood. Physiological indices can provide valuable information about fecundity, survival, health and population age structuring which is fundamental to cetacean research and population management. However, such information is often difficult to obtain from wild cetaceans as they surface infrequently and often live in remote or logistically challenging locations. As such, few methods currently exist for the assessment of physiological parameters of free ranging, large cetaceans. This dissertation paired existing methods of physiological examination with novel approaches in order to better understand the basic physiology and overall health of humpback whales. Specifically, six enzyme immunoassays were validated for use in humpback whales for progesterone, testosterone, cortisol, corticosterone, aldosterone and DHEA-S, an algorithm termed "Morphometer" was developed to automate the process of measuring and analyzing morphometric measurements, and hormones and body condition metrics were paired to determine whether pregnancy status can be detected from aerial photographs. This project seeks to lay the groundwork for long term monitoring of humpback whales that can provide critical information to managers. By using baseline physiological indices and tools to rapidly analyze these metrics that I developed here, managers and researchers will be able to analyze current and future samples within a longitudinal context and make management decisions based on more accurate biological information for these populations.
    • The visual language of Turkish roman dance

      Carter, Bethan J.; Shoaps, Robin; Plattet, Patrick; Yamin-Pasternak, Sveta (2021-08)
      Utilizing Peircean semiotics and Dell Hymes' Ethnography of Communication, this research analyzes the dance style known as Roman havasi or, Turkish Roman dance. Elements and influences under consideration include costuming, dance vocabulary, musical instruments and traditions, gender-based stylistic differences, spheres of performance, audience member and participant demographics, and notions of authenticity in embodiment and presentation. An abridged history of the Roman is also presented, including public policies that influence the rights and lifestyle of Turkish Roman, as such factors have influenced their sense of social belonging as well as their dance and musical expressions. Romani people have experienced marginalization wherever they have immigrated, and scholarship regarding them has not always been beneficial. This thesis aims to increase the visibility, recognition, and appreciation of their culture. Research data was collected via participant observation as a Turkish Roman dance student and performer in Anchorage, Alaska, and from structured interviews with instructors and performers. Video footage was also gathered for analysis and was obtained by the author or via public domain websites. This thesis is accompanied by a collection of video clips featuring various elements of Turkish Roman dance referenced herein, and is available as supplemental material.
    • Impacts of cover cropping and tillage on weed populations and soil nutrients in a sub-Arctic environment

      Carr, Erin L.; Zhang, Mingchu; Seefeldt, Steven; Sparrow, Stephen (2021-08)
      One of the biggest challenges for organic crop and vegetable producers is weed control. Traditional practices, such as cover cropping and tilling, aid in controlling weeds on fallow land. However, both methods can impact soil nutrient availability. For producers in sub-Arctic regions with a limited growing season, such as interior Alaska, these practices would remove valuable farm land from production for at least a year and potentially impact soil nutrients. The objective of this study was to determine cover cropping and tilling intervals that would reduce weed seedbank size without negatively influencing soil nutrient availability and taking land out of production for multiple growing seasons. A two year (2008 and 2009) study at two interior Alaska farms (UAF-AFES and Rosie Creek) measured weed density, weed seedbank size, and extractable macro and micro soil nutrients at two soil depths (0-15 cm, 15-30 cm) among seven treatments: continuous tillage (TILL), continuous cover crop (CC), tillage + middle season cover crop (TC), and cover crop + middle season tillage (CT). Two species, Hordeum vulgare L. (Albright barley) and Pisum sativum subsp. Arvense (Austrian winter field peas) were planted as cover crops. Field weed estimates were measured prior to treatment applications (tillage or planting) followed by soil core samples post treatment for weed seedbank analysis. Soil cores were collected for soil nutrient analysis at the beginning, middle and end of the growing season. In 2008 at UAF-AFES, weed density among treatments were different mid-season (p<0.05) and the subsequent growing season (p<0.05), TILL and TC treatments reduced weed populations. Weed seedbank size was different among treatments the subsequent growing season (p<0.05). In 2008 at Rosie Creek, only the subsequent growing season were there differences among treatments (p<0.05). In 2009 both study sites had no differences among treatments at any sample period. Extractable soil nutrients varied among location, year and soil depth. The highest concentrations of nitrate (NO₃-N) were measured in the tillage treatments and the lowest concentrations of NO₃-N were measured in the cover crop barley treatments (p<0.05). The research suggested that continuous tillage and tilling through the first half of the growing season has a greater impact on reducing the weed population, but can impact soil nitrate concentrations. Producers may be able to till and cover crop within one growing season, but this is highly dependent on weed density and there may be a loss of soil available nutrients for subsequent crops.