• Exploration of mesospheric metal layers from Chatanika, Alaska

      Martus, Cameron M.; Collins, Richard L.; Mölders, Nicole; Sassen, Kenneth (2013-08)
      Layers of free metal atoms exist in the mesopause region of the atmosphere, generally between 80 and 100 km altitude. Resonance fluorescence lidar provides the best way to measure the structure and dynamics of these metal layers. Resonance lidar observations using tunable dye lasers are conducted at the Lidar Research Laboratory (LRL) of Poker Flat Research Range (PFRR), Chatanika, Alaska (65°N, 147°W). In this thesis, we present three fundamental aspects of mesospheric resonance lidar studies: lidar system commissioning and operation, analysis of temporal variations in the metal layers based on observations, and observations of the nickel layer. An excimer-pumped dye laser system has been used in the past for observations at LRL-PFRR, and we report on the alignment and testing of this system as well as the deployment of a new Nd:YAG-pumped dye laser system. Both of these systems are tested with observations of the sodium layer at 589 nm. Through an analysis of simultaneous observations of the sodium and iron layers taken in the past at LRL-PFRR, we study the common motion of the two layers and suggest an external forcing mechanism for the motions. We find that the motion of the layers is, in most of the observations, consistent with downward propagating gravity waves. Based on elemental abundances in meteors, the most likely source of mesospheric metal layers, we expect to find a nickel layer, yet such a layer has not been reported. We attempt to detect the layer using resonance lidar at the 337 nm nickel absorption line. We make several likely detections of the layer and present an initial estimate of the nickel profile. Signals received in the nickel measurements are as expected from a simulation based on signals received in past observations of sodium and iron.
    • An exploration of own and cross-price elasticity of demand for residential heating in the Fairbanks North Star Borough

      Graham, Noelle J.; Little, Joseph; Baek, Jungho; Kennedy, Camilla (2019-05)
      The purpose of this study is to utilize community level household energy consumption data to determine the short-run own- and cross-price elasticity of heating oil and wood using the proportionally calibrated almost idea demand system model. Elasticity values can identify how residents of the Fairbanks North Star Borough will potentially alter home heating practices in response to a change in home heating oil price. Results indicate that values for own-price elasticity for oil is -0.259, with a 95% confidence interval of [-0.272, -0.246]. Based on predicted values a 1% increase in the price of heating oil is estimated to result in a reduction of 0.259% in the quantity of residential heating oil consumed by the average household. Cross-price elasticity estimates of wood with respect to a change in the price of oil is 0.198 with a 95% confidence interval of [0.171, 0.234]. Based on predicted values, a 1% increase in the price of oil is predicted to increase wood consumption by 0.198%. In addition, this study utilized a Monte Carlo Simulation with estimated elasticity parameters to predict the change in household level energy consumption of wood and heating oil given an increase in heating oil prices. Approximately 71% of households are predicted to decrease overall energy consumption. 83.5% of households are predicted to decrease oil consumption, and 57.3% of houses are predicted to increase wood consumption. Through evaluating household's energy consumption decisions in the face of changing prices, these results can inform effective air quality policies.
    • An exploration of two infinite families of snarks

      Ver Hoef, Lander; Berman, Leah; Williams, Gordon; Faudree, Jill (2019-05)
      In this paper, we generalize a single example of a snark that admits a drawing with even rotational symmetry into two infinite families using a voltage graph construction techniques derived from cyclic Pseudo-Loupekine snarks. We expose an enforced chirality in coloring the underlying 5-pole that generated the known example, and use this fact to show that the infinite families are in fact snarks. We explore the construction of these families in terms of the blowup construction. We show that a graph in either family with rotational symmetry of order m has automorphism group of order m2m⁺¹. The oddness of graphs in both families is determined exactly, and shown to increase linearly with the order of rotational symmetry.
    • Explorations of intergenerational healing, resilience, and post-traumatic growth by helpers and healers on the Blackfeet Nation

      Hoyt, Tyler J.; Gifford, Valerie M.; Whipple, Jason; Topkok, Sean; David, Eric John (2019-12)
      This project explored intergenerational healing, resilience, and post-traumatic growth within the context of the Blackfeet Nation in Montana, the roles of helpers and healers in this setting, and community experiences of familial trauma and the idiosyncratic healing and resilience processes according to their worldview. The central goal of this study was to provide a contemporary public narrative surrounding healing and resilience as these topics related to historical and intergenerational trauma in this specific community. This exploratory study was composed of the narratives of 14 co-participants working as helpers and healers on the Blackfeet Nation. Indigenous narrative and a cosmic relationality were honored and a phenomenological method of Gadamerian hermeneutics was utilized. Seven central themes arose in the process of data analysis including Spirituality, Trauma, Healing, Resilience, Helping Role, Community, and Blackfeet Worldview. Co-participants explored contemporary experiences of collective intergenerational trauma of those they served as well as personal and familial processes of healing and resilience. The centrality of spirituality, cultural immersion and personal cultural identity were discussed as aspects of intergenerational healing and resilience. A holistic and culturally idiosyncratic understanding of personal and intergenerational healing was emphasized including spiritual, emotional, mental, and physical modes of healing. Patterns of healing experienced collectively and synergistically within family systems and between community members were also identified.
    • Exploring relationships between employees' locus of control, individualism and collectivism orientation, and upward dissent message strategies

      Ingwar, Nadia Ingerslew; Sager, Kevin L.; Richey, Jean A.; DeCaro, Peter A. (2014-05)
      This thesis investigated the relationships among individualism and collectivism, locus of control, and upward dissent. Students at a northwestern university were asked to complete a survey that measured the participants' levels of individualism and collectivism, locus of control orientation, and self-reported use of upward dissent message strategies. As predicted, internal locus of control and individualism were significant positive predictors of upward dissent. Unexpectedly, however, external locus of control and collectivism were also significant positive predictors of upward dissent. The research questions concerned the ability to predict the use of particular upward dissent message strategies. Use of each of the four strategies could be predicted from employees' locus of control and individualism and collectivism orientation.
    • Exploring supportive and defensive communication behavior and psychological safety between supervisors and their subordinates

      Strehl, Mary E.; Sager, Kevin L.; DeCaro, Peter A.; Jarrett, Brian (2015-05)
      This project explores the relationship between supportive and defensive communication behavior and psychological safety in the organizational setting. A paper and pencil survey measuring team psychological safety and supportive and defensive communication behaviors was administered to participants in the northwestern region of the United States. Supervisor use of supportive communication behavior was hypothesized to be positively correlated with employee psychological safety. Support was found for the hypothesis. This research sought to expand the scope of our understanding of psychological safety in an organizational setting while highlighting the benefits of using supportive communication behavior.
    • Exploring The Challenges Of School Counseling: Voices From Rural Alaska

      Cook, Christine Rojas; Barnhardt, Raymond (2011)
      School counselors in rural locations deal with many of the same issues and concerns of those in most urban areas, but have several additional challenges due to the geographic and demographic characteristics of their populations. The research in this dissertation investigated the specific challenges experienced by school counselors in the state of Alaska. All school counselors working in a rural public school were surveyed to determine what challenges they experienced, what resources they utilize, what additional resources they would like, and to discuss any information they believed would be helpful for a counselor about to enter the rural school setting. From the original 93 survey responses, 24 counselors were interviewed to provide further depth to the investigation. Analysis revealed similar challenges as discussed previously in the literature regarding rural counselor practice, but highlighted crisis situations, isolation variables, limited community resources, multiple roles, rural culture issues, and cultural issues. Alaska school counselors currently utilize a variety of resources to help them address the concerns in their communities. They did not request anything different than the resources they currently access, but rather wanted more of those resources. Recommendations are made for school counselors, school districts, state organizations, and counselor education training institutes.
    • Exploring the connection between salmon and well-being to strengthen a food system intervention in western Alaska

      Nu, Jennifer; Bersamin, Andrea; Hoeft, Theresa; Lopez, Ellen; Loring, Philip (2014-08)
      Effective interventions aimed at changing dietary behaviors in indigenous communities can benefit from understanding local perceptions and values connected to culturally important foods. Formative research in collaboration with community members to explore these perceptions is a necessary step in the process of designing effective interventions, yet few studies elaborate on the details of this process. Research conducted in a remote Yup'ik community in Western Alaska explored the connection between salmon and well-being to strengthen a food system intervention. Qualitative data were collected, collaboratively reviewed with a community work group, and analyzed using thematic analysis. Nine major themes emerged from the analysis to represent aspects of well-being supported by salmon. Ongoing collaboration between academic and community partners informed the development of the final intervention design using the formative research findings. The development of this process to incorporate local meanings of a culturally important food into a food system intervention elucidates one way a community-academic partnership can strengthen food system interventions in indigenous communities.
    • Exploring the impact of culture in strengthening the stewardship of compact funds in the Federated States of Micronesia: a convergent parallel mixed methods design

      Asuncion-Nace, Zenaida; Duke, Rob; Walter, Ansito; Skya, Walter; Ho, Kevin; Perez, Karri (2019-08)
      As the U.S. attempts to create conditions for a self-sufficient Federated States of Micronesia (FSM), significant uncertainty remains. Based on the agreement between the U.S. and the FSM under the Compact of Free Association Act (COFA) of 1985, Federal funds are transferred to FSM to sustain its economy in return for the free use of FSM's land, water and air for U.S. military purposes. As originally envisioned, this transfer would be complete by 2023, but with only a few years remaining, this goal seems unattainable. Neither the U.S. government nor the FSM seem willing to make concessions. With the U.S. demanding better oversight and accountable accounting practices, and the U.S. Financial Stability Board (FSB) asserting culturally informed management prerogative, both entities' interests are imperiled, especially as China seems to be waiting in anticipation to pick up the pieces should an impasse be reached. This mixed-methods research (surveys and interviews) was conducted utilizing the employees of two FSM national government departments: The National Department of Education and National Department of Public Health and Human Services. These two FSM departments receive the largest share of federal assistance. This research paper attempts to generate insights on the impact of culture in strengthening the accountability of Compact funds in the FSM. The study explores the social stratification and hierarchy in Micronesian societies in terms of stewardship competencies to fulfill the federal administrative requirements in the management of federal funds. What works for the mainland U.S. may not work worldwide. The effect and import of cultural influences cannot be understated, particularly in relationships amongst cultures that vary widely, as do those of the U.S. and FSM. It's important to understand the nuances of how the notion of stewardship is perceived and exercised in other countries, especially when the interests of two nations converge, while their cultures do not. This study represents the present environment in FSM governance. Understanding culture and its influences is an essential step in considering the real effect on a leadership style, transcending to ethics and stewardship. A leadership style can have a different effect or impact in other societies relative to the cultural environment in which it is adopted. This research finds support for the notion that leadership styles cannot be embraced and applied in similar manner throughout the various cultures or nations. There are a wide variety of different leadership styles across the globe; each individual region possesses its own cultural idiosyncrasies, and naturally these are reflected in the way in which people lead. This dissertation concludes with eight specific recommendations for implementing structural and policy reforms which will strengthen the relationship between the U.S. and FSM and better prepare FSM to be self-sufficient.
    • Exploring the mechanisms behind nondiffusive transport in a simple turbulence model

      Ogata, Douglas; Newman, David; Sánchez, Raul; Wackerbauer, Renate; Ng, Chung-Sang (2017-05)
      Elements for nondiffusive transport have been identified in a plasma turbulence model based on the slab drift-wave model. Motivated by the self-organized criticality paradigm, a standard set of drift-wave equations in doubly-periodic spatial domain has been elevated to include a flux-driven background profile with critical gradients. The profile is maintained by the turbulence induced flux from the source to the sink. Tracers that follow the Lagrangian trajectories are the primary transport characterization technique. The competition between down-gradient relaxations and self-generated flows highlights the dual reactions to local steepening of profile gradients, which leads to different transport regimes. An additional external sheared flow further inhibits down-gradient transfer and acts as another critical threshold condition that can lead to flow-driven instabilities. Superdiffusive transport is observed primarily when radial relaxation events dominate while subdiffusive character become more prominent with self-generated and external poloidal flows. Diffusive transport exists when the superdiffusive and subdiffusive components are in balance. The interplay between turbulent relaxation and self-generated sheared poloidal flows, that form the basis for the transport explored in this model, is absent unless a flux-driven setup is used. Most of the rich dynamics were not present when running the simplified model without an equation for background profile evolution. Nondiffusive transport characteristics can also be recovered from a passive scalar field that is advected by the turbulent flow with an inherent diffusivity. The spread of a highly localized cloud of tracers and a passive scalar field reasserts the equivalence between the Lagrangian and quasi-Lagrangian frames. The coincidence between the passive scalar field with the tracers provide a regime of validity where existing experimental technique can be used to characterize transport from two-dimensional experimental data. The results from this work highlight the key features of flux-driven turbulent transport leading to nondiffusive transport. Specifcally, the dual reactions to the local steepening of profile gradients exposes the multiscale feature of turbulent transport that becomes more apparent under a flux-driven profile. The quantification of nondiffusive transport characteristics from the evolution of a passive scalar can have important implication towards the fundamental understanding of fluid turbulence and turbulent transport.
    • Exploring the potential for technology-based nutrition education for low-income families in Alaska

      Power, Julianne M.; Bersamin, Andrea; Johnson, Jennifer; Braun, Kathryn (2016-08)
      This thesis addresses the need to identify more accessible and cost-effective ways for federal food assistance programs to deliver nutrition education to Alaska Native people living in rural and remote communities in Alaska. The ultimate aim is to explore whether technology-based nutrition education is a feasible and acceptable alternative to traditional face-to-face nutrition counseling. I begin this thesis by examining the preliminary efficacy and acceptability of an 11 week text message-based intervention to promote fruit and vegetable (F&V) intake among parents with young children (n=74) using a pre-post study design. Although there were no changes in pre-post measures, most participants reported positive changes in attitudes and behaviors related to F&V intake since participating in the intervention. Participants thought the intervention was credible (80.8%), found texts useful (71.6%), and would recommend the program to a friend (82.2%).The next chapter explores the feasibility of technology-based nutrition education in rural and remote areas of the state by estimating the use of media technology among Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) participants (n=975) in Alaska Native communities using a self-administered, mailed questionnaire. The response rate was 37.7% (N=368). Respondents were primarily Alaska Native (99.1%) women (97.5%) between 18-29 years of age (56.6%). Smartphone (78.8%) and Facebook (80.3%) use were comparable to national averages, but having a computer at home (38.4%) was much less likely. Text messaging was common, with 93.3% of respondents reporting use at least once per week or more frequently. Potential barriers included slow internet (51.0%), no computer access (42.1%), and high cost of internet (35.1%). Nutrition education delivered via mobile devices is an ideal way to reach Alaska Native people in remote communities, provided that such programs limit the amount of cellular data necessary for participation. The findings from this thesis provide important evidence supporting the use of text messaging and other media technology in nutrition education efforts by WIC and other federal food assistance programs for Alaska Native people living in rural and remote communities. These findings will inform technology-based nutrition education efforts throughout Alaska.
    • Exploring the potential role of late stage predation and Chinook salmon age structure

      Manishin, Kaitlyn A.; Seitz, Andrew C.; Westley, Peter A. H.; Cunningham, Curry J.; Goldman, Kenneth J. (2018-12)
      Chinook salmon (Oncorhynchus tshawytscha) populations across the North Pacific have displayed a decrease in body size-at-return resulting from declines both in age- and body size-at-maturity. These changes have precipitated the loss of the oldest age classes in some populations and have occurred throughout the range of this species, suggesting a shared - yet currently unknown - driver in the common marine environment. A hypothesis for the cause of these changes is intense and/or selective predation marine mortality after the first winter in the ocean, potentially from predators selectively removing relatively large sub-adult Chinook salmon. Here I consider the question: under what circumstances could predation on large sub-adult individuals by salmon sharks (Lamna ditropis) change the age structure of a Chinook salmon population? To address this question, I first estimated total per capita prey consumption by salmon sharks - an increasingly acknowledged predator of salmon on the high seas - using three methods: 1) daily ration requirement, 2) bioenergetic mass balance, 3) and a von Bertalanffy growth model. Second, I examined the effects of additional predation on an indicator Chinook salmon population from the Yukon River by simulating alternative predation scenarios with a stage-structured life cycle model. Scenarios described the strength and selectivity of predation, and the resulting simulated age structure was then compared to observed demography. The selectivity and intensity of removals required to produce this change in age structure were considered in the context of top predators, focusing on salmon sharks. The daily ration method yielded individual salmon shark consumption estimates of 1461 and 2202 kg·yr-1, the mass-balance method produced estimates of 1870 kg·yr-1, 2070 kg·yr-1, 1610 kg·yr-1, and 1762 kg·yr-1, depending on assumed diet, and the growth model output estimates of 16,900 kg·yr-1 or 20,800 kg·yr-1, depending on assumed assimilation efficiency. The per capita prey consumption estimates from the mass-balance method may be the most realistic because they incorporated life history data specific to salmon sharks and did not produce extreme values. Taken as a whole, these estimates suggest salmon sharks have energetic requirements similar to those of piscivourous marine mammals and corroborates conclusions of previous research suggesting that endothermic fishes exhibit metabolic rates similar to marine mammals. The simulated mortality scenarios that most closely mimicked observed shifts in age structure of the indicator Chinook salmon population focused intense and selective predation on the third year of Chinook salmon residence in the ocean. This simulated predation is corroborated by emerging results from an independent electronic tagging study in which tagged Chinook salmon experienced high predation rates, and research suggesting that killer whales (Orcinus orca) selectively prey upon Chinook salmon in their third year at sea. In summary, salmon sharks likely have high energetic requirements that could result in a large biomass of prey consumed, Chinook salmon populations are sensitive to predation during the third ocean year, and salmon sharks and other predators appear to frequently consume fish at that ocean stage. Taken together, these lines of evidence point to a potentially important mechanism for top down pressure on Chinook salmon populations that may explain observed changes in age-at-return, which in turn can affect population productivity. Future work and more robust data on predator distributions and abundances are needed to explore this finding further.
    • Exploring the relationship between diet and osteoporosis in medieval Portugal using stable isotope analysis

      Luxton, Sharla Ann; Clark, Jamie; Halffman, Carrin; Hemphill, Brian (2015-08)
      This project investigates the relationship between health and diet in medieval Portugal by combining data on the occurrence of osteoporosis with information on past diet derived from stable isotope ratios. The aim of this project is to identify whether different sources of protein influenced the prevalence of osteoporosis in three populations. Individuals from three different regions of Portugal were previously evaluated for bone mineral density at the University of Coimbra, Portugal, and bone samples from 91 of these individuals underwent stable isotope analysis at the University of Alaska Fairbanks. Collagen suitable for isotopic analysis was extracted from all individuals and indicated a negative correlation between bone mineral density (BMD) and carbon and nitrogen isotope values for females at one site and a positive correlation for males at another site. These results, combined with the lack of a clear relationship between BMD and nitrogen isotope values for the other subgroups, suggest a complicated relationship between dietary protein source and the occurrence of osteoporosis. While sample sizes are small, the data indicate that future analysis is warranted, particularly considering the high incidence of osteoporosis and the economic and individual strain of the disease.
    • Exploring the relationship between forest resource users and their disappearing forest: what do rural Gambians think are the causes and solutions for deforestation?

      Harris, Samantha; Todd, Susan; Gasbarro, Tony; Seefeldt, Steven (2017-06)
      This is a case study of a small rural community in The Gambia where I was a Peace Corps volunteer for 27 months. The savannah woodland there is classified as a dry tropical forest and like many such areas in the Sahel, the population is growing rapidly. During my time there, I observed a great dependence on local forests but no apparent management. One man told me, "If all the trees perish, then we will all perish." Given this level of dependence, I was surprised to see little evidence that they were planting trees or taking other measures to protect the forest. I wanted to find out just how dependent people were on the forest and whether they saw deforestation as a problem. If they saw it as a problem, what did they feel were the causes of it and what did they think would solve it? Since I was living in the area, I was able to use participant observation as a method in my research. I also used semi-structured interviews of key informants and focus group interviews in five communities that were located close together. I found that the people are extremely dependent on the local forest for firewood, lumber for houses and fences, foods like baobab and mangoes, and herbs for medicines (they had limited access to commercial medicines). This dependence places them in a precarious situation as rural poverty and food insecurity forces farmers to expand their agricultural fields at the expense of the forests. Everyone saw deforestation as a problem and noted that they have to walk farther to gather firewood and that the forest was once thick with trees and wild animals, but now "many trees have perished" and there are few animals. They saw population growth as the primary cause of deforestation, because that forces them to clear trees to make room to grow more crops. They also mentioned illegal logging, drought and bushfires as problems for the forest. They viewed tree planting as the primary solution and would like to plant trees near their homes where they could protect them, but there are a host of challenges to growing seedlings in this region. The biggest problems are watering the seedlings, as that requires carrying many gallons of water to each seedling on a daily basis, and protecting young trees from termites as well as goats and other animals. They would like to have more support from the Gambian government to teach them better ways to plant and grow trees, to learn more about manure and other ways to improve soil fertility, to help them pay for good fences, and to combat bushfires. There are many studies regarding tree planting, but few of them address the cultural perspective of forest use and management in the way this study does. These people face a life-threatening dilemma in trying to solve the problem of deforestation. They have had little success planting trees and will face serious shortages of essential items like firewood, lumber, medicines and food if the problem continues. They do not have the income to buy these goods. I hope this study will contribute to understanding the complexity of the situation, which in turn should assist NGOs and others to develop workable solutions to the problem of deforestation in this and other dry tropical forests of the Sahel.
    • Export Of Carbon, Nitrogen And Major Solutes From A Boreal Forest Watershed: The Influence Of Fire And Permafrost

      Petrone, Kevin Christopher; Boone, Richard; Jones, Jeremy (2005)
      Detailed observations of stream, soil, and groundwater chemistry were used to determine the role of fire, permafrost and snowmelt processes on the fluxes of carbon, nitrogen and major solutes from interior Alaskan catchments. We examined an experimentally burned watershed and two reference watersheds that differ in permafrost coverage (high, 53%; medium-burn, 18%; and low, 4%) during the FROSTFIRE prescribed burn in July 1999. The fire elevated stream nitrate concentrations for a short period during the first post-fire storm, but nitrate declined thereafter, suggesting that less severe fires that leave an intact riparian zone may have only a short-term effect on stream chemistry. Nevertheless, we found fundamental differences in hydrochemical differences between watersheds due to the presence of permafrost. Flowpaths in the low-permafrost, likely from the riparian zone, depleted stream nitrate levels while flowpaths in the high permafrost watershed, generated from more distant hillslopes, were a source of nitrate. All watersheds were sources of organic solutes during snowmelt and summer storms. On an annual basis, watersheds were net sources of every individual ion or element (Cl-, PO42- , SO42-, DOC, DON, NO3 -, Na+, K+ Mg2+, Ca2+) except NH4+, which was a small fraction of the total N concentration in streams. The concentration of NO 3- was high for an ecosystem with low atmospheric N deposition and compared to non-Alaskan boreal and temperate watersheds, resulting in net N loss. These findings suggest that boreal watersheds in the discontinuous region of interior Alaska may be fundamentally different in their capacity to retain N compared to ecosystems with net N retention.
    • An exposition on the Kronecker-Weber theorem

      Baggett, Jason A. (2011-05)
      The Kronecker-Weber Theorem is a, classification result from Algebraic Number Theory. Theorem (Kronecker-Weber). Every finite, abelian extension of Q is contained in a cyclotomic field. This result was originally proven by Leopold Kronecker in 1853. However, his proof had some gaps that were later filled by Heinrich Martin Weber in 1886 and David Hilbert in 1896. Hilbert's strategy for the proof eventually led to the creation of the field of mathematics called Class Field Theory, which is the study of finite, abelian extensions of arbitrary fields and is still an area of active research. Not only is the Kronecker-Weber Theorem surprising, its proof is truly amazing. The idea of the proof is that for a finite, Galois extension K of Q, there is a connection between the Galois group Gal(K/Q) and how primes of Z split in a certain subring R of K corresponding to Z in Q. When Gal(K/Q) is abelian, this connection is so stringent that the only possibility is that K is contained in a cyclotomic field. In this paper, we give an overview of field/Galois theory and what the Kronecker-Weber Theorem means. We also talk about the ring of integers R of K, how primes split in R, how splitting of primes is related to the Galois group Gal(K/Q), and finally give a proof of the Kronecker-Weber Theorem using these ideas.
    • Expression and function of the ATP dependent chromatin remodeler imitation switch in Xenopus laevis

      Dirscherl, Sara Suzanne (2005-05)
      One of the first ATP-dependent chromatin remodeling complexes was first identified and characterized over ten years ago. Since then, the number of distinct ATP-dependent chromatin remodeling complexes and the variety of roles they play in nuclear processes have become dizzying. Some of the processes include transcription, replication, repair, recombination, and sister chromatid cohesion. The SWI/SNF-related ATP-dependent remodelers are divided into a number of subfamilies, all related by the SWI2/SNF2 ATPase at their catalytic core. In nearly every species where researchers have looked for them, one or more members of each subfamily have been identified. Here I have investigated the ATP dependent chromatin remodeler ISWI. I have shown that Xenopus ISWI, which is in its own subfamily, has a critical function in developing neural tissue. Whole mount in situ hybridization shows ISWI localized in neural tissue including the eye and developing neural tube. Injection of antisense ISWI RNA, morpholino oligonucleotides or dominant-negative ISWI mutant mRNA into fertilized eggs misregulates genes involved in patterning and development, such as BMP4 and Sonic hedgehog (Shh), and ISWI binds to the BMP4 gene in vivo. Partial inhibition of ISWI function results in aberrant eye development and the formation of cataracts. These data suggest a critical role for ISWI chromatin remodeling complexes in neural development.
    • Expression and function of Williams syndrome transcription factor (WSTF) in the neural development of Xenopus laevis

      Malakar, Sreepurna (2008-05)
      Imitation Switch (ISWI) is a member of the Switch2/Sugar Non-Fermenting2 (SWI/SNF2) superfamily of ATP (adenosine triphosphate) - dependent chromatin remodelers. Twenty different ISWI complexes have been identified so far in yeast, Drosophila, Xenopus and mammals. Three ISWI-containing complexes, WSTF-ISWI chromatin remodeling complex (WICH), ATP-dependent chromatin assembly and remodeling factor (ACF) and chromatin accessibility complex (CHRAC), have been characterized in Xenopus. Loss of ISWI function in Xenopus embryos results in severe defects in neural and eye development, including loss of retinal differentiation and formation of cataracts. We have begun to dissect the contributions of individual ISWI dependent complexes to development, by using in situ hybridization and antisense morpholino knockdowns against subunits unique to different ISWI-containing complexes. Here I have investigated the WICH complex in Xenopus and have targeted the WSTF subunit. Whole mount in situ hybridization shows WSTF localized in the neural tissue including eye, brain, branchial arches and neural tube/ spinal cord. Injection of antisense morpholino oligonucleotides into fertilized eggs leads to misregulation and aberrant expression of genes involved in neural patterning and development, such as Bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh). Whole mount in situ hybridization shows mislocalization of BMP4 in the probable deformed neural tube of WSTF knockdowns. All these data suggest that WSTF is critical for neural development.
    • Expression And Mechanisms Of Hibernation In The Artic: The Alaska Marmot And Arctic Ground Squirrel

      Lee, Trixie Nicole; O'Brien, Diane; Buck, Loren; Taylor, Barbara; Barnes, Brian (2012)
      The Arctic is home to animals that have taken adaptations to overwintering to extremes. In this dissertation, I have investigated one of these adaptations, hibernation, in two species from the Arctic, the Alaska marmot (Marmota broweri) and the arctic ground squirrel (Urocitellus parryii ). The expression of hibernation under natural conditions in these species was compared by collecting body temperature records of free-living individuals. The Alaska marmot, a highly social species, demonstrated extreme synchrony in body temperature patterns among a family group, indicating a strong reliance on social thermoregulation. In contrast, the arctic ground squirrel was confirmed to be a solitary hibernator that reduces body temperature below freezing during torpor. Both species must produce heat when soil temperatures are significantly below freezing for most of the winter. At these subfreezing ambient temperatures, the arctic ground squirrel has shown an increasing reliance on nonlipid fuel during torpor, driving a loss of lean mass during hibernation of ~20%. I calibrated deuterium dilution to repeatedly estimate body composition in this species, which dramatically changes adiposity through its annual cycle, and used this technique to quantify lean mass loss throughout hibernation in a study of tissue metabolism. I also developed and applied the natural abundance of nitrogen and carbon stable isotopes as tools for monitoring differential tissue metabolism and differentiating mixed metabolic fuel use in the arctic ground squirrel. These data clarified the mechanism of change in nitrogen stable isotopes and indicated that hibernating ground squirrels rebuild organ tissues while breaking down muscle tissue to meet energetic demands. Furthermore, I corroborated a shift in metabolic fuel use toward nonlipid sources during torpor at low ambient temperatures by using the carbon isotope ratio in exhaled breath in combination with respiratory quotient. This dissertation combines studies of hibernation patterns in free-living animals with experimental data on the tissues and fuels being catabolized at very low temperatures to broaden our understanding of how small mammals successfully hibernate in severe winter conditions. It also presents the development and use of stable isotope ratios as physiological tools in hibernating species.
    • Extended methods of notation in Josh Levine's Les yeux ouverts and Daniel Tacke's Einsamkeit

      Dowgray, Sean; Palter, Morris; Zilberkant, Eduard; Post, William (2015)