Seismological constraints on tectonics of southern and central Alaska: Earthquake locations and source mechanisms

Ratchkovski, Natalia Anatolievna University of Alaska Fairbanks 2001 해외박사(DDOD)

The major emphasis of this thesis is on investigations of earthquake locations and source mechanisms and what we can learn about Earth structure from them. I used a Joint Hypocenter Determination (JHD) method to improve the earthquake locations obtained after routine data processing. Over 15,000 subduction zone earthquakes in southern Alaska and over 3,600 crustal earthquakes in central Alaska with magnitudes <italic>M_L</italic> ≥ 2 that occurred from 1988 to 2000 were relocated. I found that the relative earthquake locations can be improved with the use of the JHD relocation technique (30–60% reduction in RMS residuals). Thus, many details of the subduction zone geometry and crustal structure can be mapped. To constrain source characteristics, I use a moment tensor inversion method that simultaneously inverts for the source parameters and velocity structure. First, I apply this technique to the sequence of strong earthquakes in the Kodiak Island region, including December 6, 1999 and January 10, 2001 M_W 7 events. Next, I expand this approach to moderate-sized (<italic> M_L</italic> ≥ 4) crustal earthquakes in central Alaska and calculate 38 moment tensors. I demonstrate that the moment tensor inversion of regional waveforms provides reliable results even when recordings from a single broadband station are used. A catalog of the moment tensors together with the focal mechanisms obtained using conventional P-wave first motion analysis is used to calculate principal stress directions in central Alaska. I find that the stress state in the crust is inhomogeneous and that the orientation of the maximum compressive stress changes from a SE-NW to SSW-NNE orientation from west to east across interior Alaska. One more topic of this thesis is the application of the array analysis to understanding characteristics of anomalous seismic phases observed in the records of the intermediate-depth Alaskan subduction zone earthquakes. I identified two secondary phases arriving with 1–3 s and 7–12 s delays after the first P-wave arrival. They are interpreted as S-to-P and P-to-S converted phases at the upper/lower surface of the subducted slab.

Stakeholder Needs and Information Use in Cryospheric Hazard Planning and Response: Case Studies from Alaska

Abdel-Fattah, Dina University of Alaska Fairbanks ProQuest Dissertati 2020 해외박사(DDOD)

The global cryosphere is experiencing rapid change, which potentially impacts the severity and magnitude of various cryospheric hazards. Alaska is home to a number of different communities that experience cryospheric hazards. These types of hazards can have potentially devastating impacts on surrounding biodiversity, communities, and infrastructure. However, there is a gap in understanding regarding what are stakeholder information needs for different cryospheric hazards, as well as what are the resources stakeholders use to meet these needs. This dissertation investigated stakeholder use of various information products and resources in three cryospheric hazard-prone communities in Alaska, which experience glacial lake outburst flood events (Juneau and the Kenai Peninsula) or anomalous high-speed sea ice motion events (Utqiagvik). In addition, a clear need exists to understand how further cryosphere change affects cryospheric hazards. Therefore, I tested whether a structured decision-making methodology can be pertinent in a cryospheric hazard context, which has previously never been done before. Specifically, I tested whether structured decision-making can be employed by decision-makers to better understand the planning needs necessary to adequately prepare for future, but uncertain glacial surges from Bering Glacier, Alaska. I found that identifying distinct stakeholder needs as well as stakeholder use of currently available information products and resources was particularly beneficial for information providers to understand how and why their products and resources are or are not used. This opened up opportunities for existing products to be enhanced or for new products to be developed. However, one of the main findings from the case study research is that there is no single information product that meets all stakeholder needs. Different stakeholders have different information needs, which need to be addressed in different ways. The structured decision-making approach tested in this dissertation was also found to be useful and applicable in a cryospheric hazard context. It can therefore be utilized as a methodological framework by decision-makers to integrate varying stakeholder needs in such a context. The findings from this research provide a unique contribution to the literature by displaying how social science and decision analysis research can support the development of information tools and resources that are both useful and relevant to those affected by cryospheric hazards.

Movement and Migration Ecology of Alaskan Golden Eagles

Eisaguirre, Joseph University of Alaska Fairbanks ProQuest Dissertati 2020 해외박사(DDOD)

Golden eagles Aquila chrysaetos are distributed across the Holarctic; however, in Alaska and other northern areas, many are long-distance migrants. Being soaring birds, golden eagles can use weather and features of the energy landscape to offset the energetic costs of movement and migration. In this dissertation, I investigate how dynamic energy landscapes, in addition to other habitat and anthropogenic features, affect the movement and migration ecology of Alaskan golden eagles; in most cases I did such by developing and applying new, biologically-appropriate statistical methods. First, I identified a single, discrete navigation decision that each eagle made during migration and determined which weather variables are primary factors in driving that decision. I found that wind was the primary correlate to the decision, consistent with eagles likely avoiding poor migration conditions and choosing routes based on favorable wind conditions. Second, I investigated how different forms of flight subsidies, which were orographic uplift, thermal uplift, and wind support, drove behavioral budgets and migratory pacing of eagles. I found a consistent daily rhythm in eagle behavior and migratory pace, seemingly driven by daily development of thermal uplift, with extended periods of slower-paced movements, consistent with periods of opportunistic foraging. Third, I investigated the effects of anthropogenic linear features, such as roads and railroads, on eagle movement during migration. I found that eagles selected for roads during spring migration and were more likely to be near roads when making slower-paced movements, which would be most frequent during times when limited thermal uplift is available. Lastly, I compared how floaters (breeding-age, non-territorial individuals) and territorial eagles used space and selected for resources, specifically interested in how their movements and space use might overlap. I found that floater space use was much more expansive, yet they only selected for habitats and resources slightly differently than territorial eagles. I also found their home ranges overlap substantially, suggesting that floaters play a key role in the population ecology of migratory golden eagles in Alaska.

DISTANT VISTAS : BRADFORD WASHBURN, EXPEDITIONARY SCIENCE AND LANDSCAPE, 1930-1960

SFRAGA, MICHAEL P UNIVERSITY OF ALASKA FAIRBANKS. 1997 국내박사

Sea Otters in Southeast Alaska: Subsistence Harvest and Ecological Effects in Seagrass Communities

Raymond, Wendel W University of Alaska Fairbanks ProQuest Dissertati 2020 해외박사(DDOD)

Keeper of the seal : The art of Henry Wood Elliott and the salvation of the Alaska fur seals

Morris, Lisa Marie University of Alaska Fairbanks 2001 국내박사

Diet and Movement of Depredating Male Sperm Whales (Physeter macrocephalus) in the Gulf of Alaska

Wild, Lauren A University of Alaska Fairbanks ProQuest Dissertati 2020 해외박사(DDOD)

Sperm whales (Physeter macrocephalus) remove fish from commercial fishing gear in high latitude foraging grounds. This behavior, known as depredation, occurs in the Gulf of Alaska (GOA) sablefish longline fishery and has increased in frequency and severity since the mid-1990s. Sperm whale foraging ecology and movements in the GOA are poorly understood but are important considerations to how depredation impacts fishery resources and whale behavior. The goals of this dissertation were to use stable isotope analysis to evaluate trophic connections between sperm whales and their prey, estimate the proportional contribution of various prey items to sperm whale diets, and use satellite tag data to evaluate movement and diving behavior of sperm whales in the GOA. Understanding isotopic variability in cetacean skin is important to evaluating dietary information from this tissue; thus, in chapter 1, I first analyzed the stable isotope ratios among layers of cetacean skin to determine how much variability there was within and across layers of cetacean skin. Results showed horizontal layers of cetacean skin to be significantly different isotopically, suggesting evidence of a dietary time series in layers of cetacean skin, where the innermost skin layer represents the most recent diet. These results were used in my second chapter to isolate the most recent diet of sperm whales from the inner layer of skin, and then to estimate proportional contributions of different prey to sperm whale diets. Results showed that the sperm whales sampled prefer sablefish, dogfish, skates, and rockfish, and that the proportional contribution of sablefish to sperm whale diets has increased over the past 15 years as depredation has increased in severity. Chapter three presented an analysis of twenty-nine satellite tags placed on depredating sperm whales in the GOA between 2007 and 2016 to explore movement and diving behavior and how these behaviors may be linked to prey preferences found in chapter 2. Tagged sperm whales in the GOA preferred the continental slope habitat and made long migrations along the slope toward Mexico and the Gulf of California, speeding up and switching behaviors from foraging to transiting when they left the GOA. Dive depths and durations exhibited individual variability and were significantly correlated to light levels, lunar cycles, sablefish fishery catch-per-unit-effort, and seafloor depth. Results suggest diving behavior tracks that of primary groundfish prey items, and dive depths become shallower in areas of high sablefish densities, as inferred from fishery catches, potentially reflecting depredation behavior. Together these results provide a much-improved understanding of the impact of depredation on sperm whale dietary preference, and show insights into the importance of the GOA as a foraging ground for endangered sperm whales.

Biophysical Chracterization of Class II Major Histocompatibility Complex (MHCII) Molecules

Osan, Jaspreet Kaur University of Alaska Fairbanks ProQuest Dissertati 2020 해외박사(DDOD)

Class II Major Histocompatibility Complex (MHCII) molecules are transmembrane glycoproteins expressed on the surface of antigen-presenting cells (APCs). APCs engulf pathogens and digest pathogenic proteins into peptides, which are loaded onto MHCII in the MHCII compartment (MIIC) to form peptide-MHCII complexes (pMHCII). These pMHCII are then presented to CD4+ T cells on the surface of APCs to trigger an antigen-specific immune response against the pathogens. HLA-DM (DM), a non-classical MHCII molecule, plays an essential role in generating kinetically stable pMHCII complexes which are presented to CD4+ T cells. When a few peptides among the pool of the peptide repertoire can generate the efficient CD4+ T cell response, such peptides are known as immunodominant. The selection of immunodominant epitopes is essential to generate effective vaccines against pathogens. The mechanism behind immunodominant epitope selection is not clearly understood. My work is focused on investigating various factors that help in the selection of immunodominant epitopes. For this purpose, peptides derived from H1N1 influenza hemagglutinin protein with known CD4+ T cell responses have been used. We investigated the role of DM-associated binding affinity in the selection of immunodominant epitopes. Our analysis showed that the presence of DM significantly reduces the binding affinity of the peptides with low CD4+ T cell response and inclusion of DM-associated IC50 in training MHCII algorithms may improve the binding prediction. Previous studies have shown that there is an alternate antigen presentation depending on antigen protein properties. Here, we showed that the immunodominant epitope presentation is dependent on the pH and length of the peptides. To study the MHCII in its native form, we assembled full-length MHCII in a known synthetic membrane model known as nanodiscs. We noted that, based on the lipid composition, assembly of the MHCII differs. Preliminary binding studies with this tool showed that there might be a difference in the binding based on the type of the nanodisc. Collectively, our results showed that the immunodominant epitope selection is a complex process that is driven by various biochemical features.

Factors contributing to weight gain among college freshman and beyond

Chipp, Cody L University of Alaska Fairbanks 2012 해외박사(DDOD)

Background: Linked with a higher risk of life threatening illnesses, obesity in the United States has become an epidemic, with a prevalence rate of overweight and obese adults of nearly 68%. Obesity rates have accelerated over the past two decades and one crucial developmental period for weight gain is among emerging adults attending college. Using an explanatory mixed-method design, this study examined contributing factors to weight gain among college students, including eliciting university stakeholders' perceptions of supports and barriers to exercising and healthy eating among students. Method: Data collection for the quantitative phase of the study consisted of two waves, baseline and 2-year follow-up. Students completed psychosocial and anthropometric measures (height, weight, and body fat percentage). Data collected for the qualitative phase of the study consisted of key informant interviews with university administrators (n=15) and seven student focus groups (n=34 students). Qualitative analyses were conducted with NVivo software and multiple coders, using a grounded theory approach to elicit major themes. Results: Students gained 1.5lbs (p>.05), with 34% of participants gaining over 5 lbs and 17% over 10 lbs. Participants who gained weight were men, ate more calories from sweets or desserts, and consumed fewer calories from fats. Increase in calories from desserts or sweets increased odds of weight gain (OR=1.075, CI=1.01-1.14) and body fat (OR=1.106, CI=1.036-1.181). Contextualizing the quantitative findings, students and administrators identified several themes that support healthy living, including access to nutritious food and physical amenities. Both groups also identified barriers, including easy access to high-calorie foods, limited recreation facilities, and policy challenges. Administrators spoke of extant health promotion efforts; however, students did not perceive active health promotion initiatives on campus. Conclusions: Dietary habits were identified drivers of weight gain among students. Extant campus supports and barriers to exercise and healthy eating among students were equally identified by students and administrators with great reliability. Implications for future health promotion efforts, food availability, recreation, and physical amenities are discussed in the context of clears sets of recommendations for stakeholder groups. Future research should explore specific dietary foods that are increasing weight and develop targeted preventions/interventions for individuals at risk.

Cultural Adaptations of Evidence-Based Practices in Supporting Children Diagnosed with Autism Spectrum Disorder

James, Krista P University of Alaska Fairbanks ProQuest Dissertati 2020 해외박사(DDOD)

Research shows that early identification and intervention result in a higher quality of life and contribution to society for individuals with Autism Spectrum Disorder (ASD). As society sees an ever-increasing percentage of individuals diagnosed with ASD, identification of culturally responsive, evidence-based practices is of critical importance. While the National Autism Center has provided a guide to evidence-based practices, minimal research has been done to determine if these practices are culturally relevant.This is a community-based formative research project. The purpose of this project was to evaluate the cultural appropriateness of the practices identified as “evidence-based practices” by the National Autism Center in the 2015 standards report, specifically a token economy system which is a positive behavioral support that utilizes the principles of applied behavior analysis to decrease challenging behaviors and increase positive behaviors. The study utilized qualitative research strategies, including surveys and interviews within the American Samoan community, to accomplish this evaluation. The surveys and interviews were analyzed using coding principles to generate themes.The researcher was contacted by the American Samoan Department of Education to provide training for educators and parents on utilizing evidence-based practices to support children with autism. The results of this study inform the content of the ongoing training efforts.