• Current Primary Production Rates Of The Western Arctic Ocean Estimated By Stable Carbon And Nitrogen Isotope Tracers

      Lee, Sang Heon; Whitledge, Terry E. (2005)
      Currently, the environments in the Arctic are rapidly changing. These changes of climate and ice conditions may alter the quantity, quality, and timing of production of ice algae and phytoplankton in the Arctic Ocean. The objectives in this study were to detect any change in the carbon production between current and previous studies and lay the groundwork for the future monitoring of ecosystem response to climate change in the different regions of the western Arctic Ocean. As an Arctic ocean mostly covered by multi or first-year ice, the deep Canada Basin had generally low photosynthetic rates and the maximum rates were found between 50 and 60 m in the basin. Based on the percentage of ice cover, the annual production ranged from 3 to 7.5 g C m-2 Z in the basin. Nutrients appear to be a main limiting factor at surface, whereas the phytoplankton activity might be limited by the low light in the Chl a-max layer. At the surface below the ice, photosynthetic activity might be controlled by both low light and nutrients. Studies of ice algae and phytoplankton at the first-year sea ice of Barrow in Alaska showed that bottom sea ice algae and phytoplankton are limited mainly by light. Therefore, the current downward trend of sea ice thickness and extent in Arctic Oceans might cause an increase in primary production or/and change in timing of the production. In addition, the composition in macromolecules of primary producers might be changed under the current ice conditions and thus nutritional status of higher trophic levels might be altered. As shallow shelf regions, Bering Strait/Chukchi Sea showed that the range of nitrate in the central Chukchi Sea was rather higher whereas the biomass of phytoplankton was lower in this study than in previous studies. Consistently, the mean carbon and nitrogen productivities from this study were almost half of values from previous studies. In conclusion, it appears that lower phytoplankton biomass in Bering Strait and the Chukchi Sea resulted in the lower carbon and nitrogen uptake rates and consequently more unused nitrate in the regions.
    • Current state of Alaska's glaciers and evolution of Black Rapids Glacier constrained by observations and modeling

      Kienholz, Christian; Hock, Regine; Arendt, Anthony; Bliss, Andrew; Braun, Matthias; Meyer, Franz; Truffer, Martin (2016-12)
      Glaciological studies rely on a wide range of input data, the most basic of which, accurate glacier extents, were not available on an Alaska wide scale prior to this work. We thus compiled a glacier database for Alaska and neighboring Canada using multi-sensor satellite data from 2000 to 2011. The inventory yielded a glacierized area of 86,720 km², which corresponds to ~12% of the global glacierized area outside the ice sheets. For each of the ~27,100 glaciers, we derived outlines and 51 variables, including centerline lengths, outline types, and debris cover, which provide key input for observational and modeling studies across Alaska. Expanding on this large-scale observational snapshot, we conducted two case studies on Black Rapids Glacier, Eastern Alaska Range, to assess its evolution during the late 20th and 21st centuries. Black Rapids Glacier, 250 km² in area, was chosen given its surge-type dynamics and proximity to critical infrastructure. Remotely sensed and in-situ elevation observations over the 1980--2001--2010 period indicated strong mass loss of Black Rapids Glacier (~0.5 m w.e. a⁻¹), with higher thinning rates over the 2001--2010 (~0.65 m w.e. a⁻¹) than the 1980--2001 period (~0.4 m w.e. a⁻¹). A coupled surface mass balance-glacier dynamics model, driven by reanalysis climate data, reproduced the glacier shrinkage. It identified the increasingly negative summer balances, a consequence of the warming atmosphere, as the main driver for the negative mass balance trend. Elevation observations in Black Rapids' surge reservoir suggested a surge was not imminent at the time of the analysis due to the lack of ice thickening. Re-initiation of sufficient elevation growth in the surge reservoir would require more favorable surface mass balances, as observed in the early 1980s. Compared to nearby Gulkana Glacier (a USGS benchmark glacier), the observed specific mass losses at Black Rapids Glacier were less pronounced, ~0.4 vs. 0.5 m w.e. a⁻¹ (1980--2001) and ~0.65 vs. 0.95 m w.e. a⁻¹ (2001--2010). The larger difference between the two glaciers' mass balances over the 2001--2010 period was partly caused by rockslide debris deposited on Black Rapids Glacier in 2002. This ~4.5 m thick debris layer, spread across 11.7 km² of Black Rapids lower ablation area, was modeled to suppress Black Rapids' glacier wide mass loss by ~20%. Modeling Black Rapids' evolution until 2100 suggested sustained glacier retreat, even under a repeated constant climate scenario, with ~225 km² of area remaining in 2100. Using a warming scenario (RCP 8.5), the modeled retreat was strongly accelerated with only ~50 km² of glacier area left in 2100. Given its thick, low-slope valley portion, Black Rapids Glacier is very susceptible to climate change. Its neighboring glaciers in the Eastern Alaska Range have similar properties, suggesting region wide glacier retreat in the future. To constrain this further, the Black Rapids case studies should be extended to the regional scale, a step now facilitated by the new Alaska wide glacier database.
    • The cyanide catalyzed dimerization of 2,3 naphthalenedicarboxaldehyde: a unique oxidative condensation product and derivatives

      McGill, Colin (2005-05)
      2,3 Naphthalenedicarboxaldehyde (NDA), in the presence of cyanide, is commonly used for the derivitization of amino acids and peptides to fluorescent 2-substituted 1-cyanobenzo[f]isoindoles, providing high sensitivity in capillary electrophoresis (CE) and high performance liquid chromatography (HPLC) separations. CE studies of the neurotransmitters glutamate and aspartate have shown the formation of a number of competitive side products. Although mentioned in the literature, these side products have not been characterized. The product, 15-hydroxybenzo[g]benzo [6, 7]isochromeno[4,3-c]isochromen- 7(15H)-one (2), is reported here, as a dimerization of NDA in the presence of cyanide and atmospheric oxygen. The structure is confirmed by IR, LRFAB-MS, IRMS, and NMR spectra. Possible mechanisms for the formation of 2, its air oxidation, and an alternative benzoin condensation product are discussed. 15-hydroxybenzo[g]benzo [6,7]isochromeno[4,3-c]isochromen-7(15H)-one (2) is easily converted to full acetals via reflux in an alcohol solvent in the presence of an acid catalyst. Oxidation by NaOCI (aq) yields 3-(3-chloro-1,4-dioxo-3,4-dihydro-1H-benzo[g]isochromen-3-yl)-2-napthaldahyde (4) by capturing hypochlorite at the position æ the enolate. Oxidation by pyridinium chlorochromate (PCC) yields naptho[2,3-c]furan-1,3-dione (5) by multiple oxidations and the formation of the anhydride.
    • Cytogenetics and sex determination in collared lemmings

      Jarrell, Gordon Hamilton; Shields, Gerald F. (1989)
      Collared lemmings (Dicrostonyx groenlandicus rubricatus) from northeastern Alaska were found to have sex chromosomes that differ from those of their Siberian congeners, because of fusion to a particular pair of autosomes. But, as in Siberian lemmings, breeding experiments showed that sex determination involves an X-linked "male-repressor," which causes carriers to develop as fertile females, despite the presence of a Y chromosome. Genotypic frequencies in offspring are consistent with Mendelian expectations of such a system, hence natal sex ratios normally favor females. X-linkage of the male-repressor in Siberia and in Alaska indicates that the gene is probably located on the "original" arms of the X chromosome rather than on the fused autosomal arms, which differ on the two continents. One consequence of the autosomal fusion to the sex chromosomes is that deleterious recessive alleles on the autosome fused to the X chromosome are more resistant to selection than at truly autosomal loci. Another consequence is that, because males are heterozygous for loci fused to the sex chromosomes, they are more resistant to inbreeding depression than XX females. One inbred line produced a natal sex ratio of 67% males. The male-bias probably resulted from loss of the male-repressor and from a lethal carried on the formerly autosomal arm of the X chromosome. As inbreeding coefficients approached 0.3, the lethal would have been homozygous in half of the homogametic (female) zygotes. This phenomenon may explain the excess of males and XY females observed in earlier work. Also, if under the natural mating system, inbreeding depression limits fitness, then fusions of autosomal chromatin to the heterochromosomes could be an adaptation to reduce inbreeding depression in heterogametic individuals. Some other genetic features of collared lemmings do suggest endogamy. Female-biased sex ratios can evolve when mating occurs between neighboring individuals who are more related than if mating occurred randomly. Two proposed sources of such "viscous" gene flow in lemmings are cyclical changes in population density and mosaic habitat. Alternatively, could climate may favor winter aggregation and inhibit the dispersal of winter-born offspring, which would mature and mate with close relatives; dispersal and outbreeding would occur in summer. Thus, inbreeding would be seasonal rather than density-dependent and it is unnecessary to suppose discontinuous habitat.
    • Daily Energy Budgets Of Caribou: A Simulation Approach (Energetics, Metabolism, Rangifer Tarandus, Migration)

      Fancy, Steven Glen (1986)
      Energetic constraints have played a major role in the evolution of caribou (Rangifer tarandus). This thesis discusses several ways in which these constraints have affected caribou morphology, physiology and behavior through their effects on the physiological condition of caribou. A computer model of daily energy budgets was used to simulate energy budgets of caribou in late winter, spring migration, and during the month of July when caribou may be harassed frequently by insects. Model outputs included estimates of metabolizable energy intake, and changes in body weight and body composition. Several of the model inputs, such as fasting metabolic rates and activity costs, were measured using captive caribou. The mean energy cost for locomotion by adult caribou was the lowest recorded for any terrestrial species, and was more strongly related to leg length than to body weight. Highly significant (p < 0.001) relationships between oxygen consumption and heart rates were used to estimate energy expenditures for activities from heart rates of caribou ranging within a large enclosure. Energy expenditures by caribou while feeding on grain at a trough, grazing, browsing and walking, as estimated from heart rates, were 12%, 18%, 18% and 46% higher than that while standing, respectively. The doubly labeled water method was validated using caribou and reindeer as a method for estimating energy expenditures by free-ranging ruminants. The computer model accurately predicted changes in body weight and composition in trials with captive caribou. The model predicted fat losses of approximately 4 kg for pregnant females of the Porcupine Herd during spring migration. During the insect season, a lactating female was predicted to be in negative energy balance on all days when insect harassment occurred for 12 h or longer. Variations in input data associated with energy intake had a much greater effect on model outputs than did factors associated with energy expenditure. Consequently, the optimal range use strategy in the absence of other constraints should involve movements to areas where the most digestible forages can be obtained and the highest eating rates attained.
    • Daily heterogeneity in habitat selection by the Porcupine Caribou Herd during calving

      Jones, Rachel Rands (2005-08)
      Caribou exhibit scale-dependent habitat selection, but variance in daily habitat selection by the Porcupine Caribou Herd (PCH) has not been examined. Investigating temporal variance in habitat selection may clarify the time period when managers may accurately estimate calving-related habitat selection. Annually, 1992-1994, approximately 70 calves were radio-collared within 2 days of birth and relocated daily until departing the calving grounds. We used daily 99% fixed kernel utilization distributions (UD's) to estimate caribou distributions, then estimated daily habitat selection using logistic regression. Habitat variables included relative vegetation greenness, greening rate, landcover class, and elevation. Spatial scales of investigation included concentrated vs. peripheral use within daily UD's, daily use within the merged extent of all daily UD's, and daily use within the historical extent of calving, 1983-2001. We used linear regression of logistic regression parameter estimates on sequential sampling days to estimate temporal habitat selection trends during the 3 weeks following capture. Overall, caribou exhibited habitat selection at multiple scales, without temporal trends, suggesting that the 21-day period following capture constituted a single domain and that managers may accurately estimate calving-related habitat selection at any point during this period.
    • Daily Meal Patterns, Voluntary Food Intake And Fattening Of Reindeer During Winter And Responses To Insulin

      Stimmelmayr, Raphaela; White, R. G.; Drew, K. L. (2001)
      I determined the effect of insulin injections on daily feeding behavior and voluntary food intake (VFI) in reindeer (Rangifer tarandus t. ) fed a concentrate ration during winter. Food intake in the absence of insulin injections was down regulated and characterized by small, regular meals during daylight and irregular and sometimes large nighttime meals. Each large nighttime meal was associated with a long post-meal interval. Daytime meal size could be predicted from an estimate of the energy deficit incurred since the previous meal; however, the occasional oversized nighttime meals were not predicted from energy deficit and suggested that appetite may be deregulated at night. I hypothesized that a low daily dose of long acting insulin (1.0 IU/kg BW, s.c.) would result in regular feeding day and night, which should result in reduced VFI. Changes in serum insulin concentration could not be detected following insulin treatment, however exogenous insulin resulted in a loss of daytime and nighttime differences in meal size and intermeal interval length and a decrease in mean daily meal size. Over a 21 d treatment period, exogenous insulin prevented an increase in VFI during a warming trend and tended to counter a linear decline in body mass and backfat depth (measured by ultra-sound) typified by control animals (given Lactate Ringer 0.005 ml/kg BW, s.c.). The influence of insulin over fat retention suggests that reindeer are capable of lipogenesis in winter. A combination of rhythmic variation in satiety response to meals during daylight and decoupling of meal size and frequency at night is suggested as an endocrine model underlying daily appetite regulation in the reindeer.
    • "Dance, dance, dance: Alaska stories"

      Wise, Zoë E.; Soos, Frank; Johnson, Sara; Heyne, Eric (2019-05)
      Dance, Dance, Dance: Alaska Stories is a collection of young women's coming of age stories. The protagonists range in age from teenager to middle aged, and the circumstances that provoke their epiphanies include events spanning from the mundane to the dramatic, such as looking through a photo album, and death. Protagonists who move through these cumulative events seek to emerge from past identities and understandings of themselves. In all of these stories the Alaskan setting is important. Physical environment, in some stories, is only perceived to be a barrier; in other stories, the setting functions as a conflict that frustrates characters' desires. Regardless, all protagonists, to a degree, ultimately realize themselves to be a barrier, and must overcome internal conflicts before coming to terms with--or abandoning--their external environment. A technical aspect of these stories that I have particularly focused on developing is the varied point of view. The ranges of points of view in these stories include retrospective first person, second person, and third person limited. In this collection I focused on the irony that each point of view, when working with a coming of age story, can provide. Narrative distance in these stories is used to highlight the difference between what the characters know and understand and what we, the readers, understand about their situations
    • Dance/movement therapy (DMT) for cancer survivors and caregivers in Fairbanks, Alaska

      Sharma, Dinghy Kristine B.; Lopez, Ellen D. S.; Rivkin, Inna D.; Swift, Joshua K.; Goodill, Sharon W. (2016-08)
      Worldwide, the burden of cancer continues to grow and impact the quality of life of patients, their families, and caregivers. Aside from the physical effects and financial costs of cancer and its treatment, a significant portion of cancer patients and their caregivers experience emotional, social, and psychological distress throughout the trajectory of their illness and extending to long-term survivorship. Despite medical advances in cancer treatment, a cancer diagnosis is still often considered to be synonymous with death, pain, and suffering. It has been established that engaging in the creative arts could promote quality of life (QOL) especially for those suffering from chronic illnesses such as cancer. Specifically, studies on dance/movement therapy (DMT) have indicated its efficacy as a complementary and holistic intervention in providing social support, decreasing fatigue and stress, increasing mobility, and enhancing overall wellbeing of cancer survivors. Results from a pilot DMT study that explored the cultural suitability, feasibility, and benefits of using DMT in the post-treatment QOL of Alaska Native cancer survivors indicated positive impacts on participants' mobility, body awareness, emotional expression, self-care, and wellbeing. Participants from the pilot study highlighted the need for providing DMT in the community and opening the DMT group to both cancer survivors and caregivers. This suggestion was in consideration of the lack of support groups available to both cancer survivors and caregivers that focus on cancer survivorship and promotion of quality of life. Existing locally available cancer support groups emphasize cancer education but are limited in meeting the psycho-social, emotional and physical needs of both cancer survivors and caregivers. The encouraging results and feedback from participants not only supported existing studies on DMT's cross-cultural benefits in promoting QOL among cancer survivors but also provided the rationale for a larger dissertation study for survivors and caregivers in Fairbanks, Alaska. It was in this context that DMT's significance in increased survivorship and QOL among cancer survivors and caregivers in Alaska was examined. The study employed a sequential, mixed methods small-N design in investigating the therapeutic benefits of DMT among cancer survivors and caregivers (N = 16) in a practice-based setting in Fairbanks, Alaska. Adhering to the principles of community-based partnership research (CBPR), the study established a collaborative partnership with the Fairbanks Memorial Hospital as it piloted a 12- week, open DMT group intervention for cancer survivors and caregivers. The study was conducted in two phases: Phase 1: DMT Intervention (12 weeks) and Phase 2: Follow-up and Findings Meeting (3 months after the last offered DMT session), which assessed DMT’s lasting effects on participants. Quantitative and qualitative data were employed to examine DMT’s effects on participant’s mental health functioning, body awareness, subjective QOL, and sense of group cohesiveness and engagement with the DMT group. Quantitative findings indicated significant improvements in participants’ mental health functioning with a moderate effect size after participation in the DMT program. Although no significant pre- to post-change was found on participants’ subjective QOL, cancer survivors reported significantly better QOL (social, emotional and functional wellbeing) at the three-month follow-up, suggesting that DMT can offer late, but possibly lasting, positive changes. Additionally, participants’ ability for selfregulation and use of avoidance as a coping tool for pain were found to increase after their DMT participation. No significant changes were noted in participants’ level of cohesion with the DMT group. However, qualitative findings indicate that participants found that the DMT program was extremely beneficial in promoting their physical, psychological, social and spiritual wellbeing and expressed overall strong positive feelings toward their DMT group. Implications for research and clinic practice were discussed as informed by the study’s strengths and limitations. One the study’s strengths is its adherence to the principles of community-based participatory research (CBPR) as an over-arching framework in guiding all aspects of the research process. By establishing a collaborative partnership between the UAF academic community and the local community hospital (Fairbanks Memorial Hospital), this study was able to build on the community’s strengths and resources in an effort to help promote cancer survivorship for cancer survivors and caregivers. Future recommendations include further strengthening collaborative community partnerships with a larger, DMT confirmatory study using a Randomized Control Trial (RCT) design, while integrating a mixed-methods approach. Implementing these strategies would help establish DMT’s efficacy as a holistic and ecologically valid intervention for cancer survivors and caregivers in Fairbanks, Alaska.
    • Data analysis and data assimilation of Arctic Ocean observations

      Stroh, Jacob Nathaniel; Panteleev, Gleb; Mölders, Nicole; Weingartner, Thomas; Rhodes, John (2019-05)
      Arctic-region observations are sparse and represent only a small portion of the physical state of nature. It is therefore essential to maximize the information content of observations and bservation-conditioned analyses whenever possible, including the quantification of their accuracy. The four largely disparate works presented here emphasize observation analysis and assimilation in the context of the Arctic Ocean (AO). These studies focus on the relationship between observational data/products, numerical models based on physical processes, and the use of such data to constrain and inform those products/models to di_erent ends. The first part comprises Chapters 1 and 2 which revolve around oceanographic observations collected during the International Polar Year (IPY) program of 2007-2009. Chapter 1 validates pan- Arctic satellite-based sea surface temperature and salinity products against these data to establish important estimates of product reliability in terms of bias and bias-adjusted standard errors. It establishes practical regional reliability for these products which are often used in modeling and climatological applications, and provides some guidance for improving them. Chapter 2 constructs a gridded full-depth snapshot of the AO during the IPY to visually outline recent, previouslydocumented AO watermass distribution changes by comparing it to a historical climatology of the latter 20th century derived from private Russian data. It provides an expository review of literature documenting major AO climate changes and augments them with additional changes in freshwater distribution and sea surface height in the Chukchi and Bering Seas. The last two chapters present work focused on the application of data assimilation (DA) methodologies, and constitute the second part of this thesis focused on the synthesis of numerical modeling and observational data. Chapter 3 presents a novel approach to sea ice model trajectory optimization whereby spatially-variable sea ice rheology parameter distributions provide the additional model flexibility needed to assimilate observable components of the sea ice state. The study employs a toy 1D model to demonstrate the practical benefits of the approach and serves as a proof-of-concept to justify the considerable effort needed to extend the approach to 2D. Chapter 4 combines an ice-free model of the Chukchi Sea with a modified ensemble filter to develop a DA system which would be suitable for operational forecasting and monitoring the region in support of oil spill mitigation. The method improves the assimilation of non-Gaussian asynchronous surface current observations beyond the traditional approach.
    • Data mining for mine-mill ore grade reconciliation at Erdenet Mining Corporation

      Sarantsatsral, Narmandakh (2016-11)
      This project investigates the relationship between the mined ore and the produced copper at the Erdenet Mining Corporation (EMC) surface copper mine in Mongolia. Four and half years of data (from 2011-2015) was obtained from the open pit mine and mineral processing plant of EMC. The mine-mill data was collected on a shift basis. The data was examined carefully using process knowledge and exploratory data analysis techniques to detect and eliminate errors. Ultimately, two years of data (2013-2014) was selected for further analysis. As is common in all mines, the material flow between the mine and mill is complicated by numerous stockpiles. The copper grade going into a stockpile may not be directly related to the copper grade exiting a stockpile. Therefore, data mining techniques applied to detect the relationship between mined ore and milled copper had to overcome the complications introduced by the presence of stockpiles. Multiple data sets were created by aggregating the original dataset by different periods. For example, in one case, data was aggregated by three shifts, to convert the data from shift-basis to daily-basis. Aggregation is an ideal way to absorb variations in material flow (tonnage and grade) between mine and mill. Data was aggregated by 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 shifts ("aggregated widths" or AW). Correlation analysis was then conducted on each version of the data to determine if a relationship existed between mine data and mill data. Correlation was computed for various period lengths, but not exceeding 28 days. Therefore, in a given year, several correlation plots were produced at each aggregated width. The number of times the correlation coefficient exceeded 0.8 in a year was measured. Results showed that correlation improved with aggregation width. The highest correlations occurred at AW of 7 or 8. This suggests that the stockpiles aggregate material for 2-3 days. Correlation analysis also included examining a time shift ("lag") between mine data and mill data. This is useful to detect whether material takes a certain amount of time before it is processed and produced as copper. However, results indicated that once the data was aggregated, a time lag greater than 0 only worsened correlation.
    • Davix: a toolset for data analysis and visualization

      Gellhouse, Amanda L.; Nance, Kara; Hay, Brian; Genetti, Jon (2014-04)
    • Deactivation and excitation of 0I(6s ⁵S) at above-thermal energies

      Enzweiler, Joseph A. (1982-05)
      Absolute collisional deactivation and excitation cross sections have been measured for a beam of O (⁵P-⁵S°) incident on N₂. The beam energy was varied from 3.95 to 10.65 keV. Cross sections for charge transfer (electron capture) of 0⁺ in N₂ were also measured in the energy range from 2.4 to 24.3 keV. The variation of light intensity 5436 Å (from the 6s-3p transition of the quintet system of atomic oxygen) emitted from the beam as a function of N₂ target pressure was fitted to a beam of kinetic equation to determine deactivation and excitation cross sections. The cross section for deactivation in N₂ decreases from 6.84 x 10⁻¹⁵ cm² at 3.95 keV to 1.5 x 10⁻¹⁵ cm² at 19.65 keV. The cross section for excitation decreases from 3.3 x 10⁻¹⁹ at 3.95 keV to 2.25 x 10⁻¹⁹ cm² at 19.65 keV.
    • The deadly affairs of John Figaro Newton or a senseless appeal to reason and an elegy for the dreaming

      Campbell, Regan; Farmer, Daryl; Kamerling, Leonard; Coffman, Chris (2020-05)
      Are you really you? Are your memories true? John "Fig" Newton thinks much the same as you do. But in three separate episodes of his life, he comes to see things are a little more strange and less straightforward than everyone around him has been inured to the point of pretending they are; maybe it's all some kind of bizarre form of torture for someone with the misfortune of assuming they embody a real and actual person. Whatever the case, Fig is sure he can't trust that truth exists, and over the course of his many doomed relationships and professional foibles, he continually strives to find another like him--someone incandescent with rage, and preferably, as insane and beautiful as he.
    • Dealing with uncertainties in integrated age-structured assessment models

      Hulson, Peter-John F.; Quinn, Terrance II; Norcross, Brenda; Marty, Gary; Adkison, Milo; Hanselman, Dana (2012-05)
      Dealing with uncertainties in integrated age-structured assessment (ASA) models has become a central focus at all levels of fish stock assessment and management. My goal in this thesis was to uncover layers of uncertainty in ASA models. There were two major components to this approach: (1) dealing with uncertainty in datasets used in ASA models through examining effective sample size, and (2) dealing with uncertainty in ASA model structure through examination of effective number of parameters and simulations of school and stock structure. From the dataset uncertainty perspective, I investigated age and length composition datasets by first identifying possible sources of error and then by evaluating if it is feasible to include this error within ASA models. From the structural uncertainty perspective, I compared historical ASA models with spatially-explicit and metapopulation scale ASA models. Sources of uncertainty in age and length composition datasets include the spatial distribution of schools and age aggregation of fish within schools. To account partially for this error at the survey design level, the optimal approach is to sample from a greater number of schools, even if the sample size within any particular school is reduced. Also, it is possible to include this error within ASA models by parameterizing and estimating effective sample size with the Dirichlet distribution. Reduced uncertainty in parameters and management quantities resulted from spatially-explicit and metapopulation ASA models when compared to historical ASA model structures. Further, with possible climate change influences on fish populations use of spatially-explicit and metapopulation ASA models will allow stock assessment scientists to accurately and more precisely predict sustainable harvest levels.
    • Decadal scale vegetation maps for the boreal forest surrounding Fairbanks, Alaska

      Huhman, Hannah E.; Prakash, Anupma; Rosselló, Jordi Cristóbal; Dewitz, Jon (2018-08)
      Vegetation maps of a selected area within the boreal forest surrounding Fairbanks, Alaska, have been generated for the nominal years of 1985, 1995, 2005, and 2015 using Landsat 4 and 5 Thematic Mapper and Landsat 8 Operational Land Imager surface reflectance products at 30 meter spatial resolution using a decision tree classification. The maps include 9 U.S. Geological Survey (USGS) vegetation classes, as well as barren land, open water, and ice/snow classes that are consistent with the classes identified in the 2001 National Land Cover Database (NLCD) map of Alaska generated by the USGS. Classification steps are based on USGS methodology, with refinements for the boreal forest, to ensure further comparison to the 2001 USGS NLCD map for Alaska. The overall weighted accuracies of first order estimates of data quality using cross validation are 93.2%, 88.4%, 93.3%, and 86.9% for the nominal years of 1985, 1995, 2005, and 2015 maps, respectively, compared to 81.8% accuracy for the USGS NLCD 2001 product. This study demonstrates that the spatial and spectral resolution of Landsat data is the best available for mapping the vegetation of Alaska's boreal forest at 1:50,000 scale. It also shows that the boreal forests surrounding Fairbanks, Alaska have witnessed a decrease in the growth of evergreen forests, an expansion of shrub and an increase in wetland distribution, all of which have been reported as impacts of a warming climate in the Arctic and Sub-arctic.
    • Decadal Variability In The Arctic Ocean: Greenland-Iceland-Norwegian Seas Ice-Ocean-Atmosphere Climate System

      Dukhovskoy, Dmitry Stanislavovich; Johnson, Mark; Proshutinsky, Andrey (2003)
      This study investigates the decadal variability of the Arctic Ocean---Greenland, Iceland, Norwegian Seas (GIN Sea) system and possible mechanisms driving variability. The theoretical foundation of this work is the theory of Proshutinsky & Johnson [1997] that two major climate states of the Arctic---Anticyclonic Circulation Regime (ACCR) and Cyclonic Circulation Regime (CCR)---are driven by variations in the freshwater contents of the Arctic Ocean and the GIN Sea. It is hypothesized that the Arctic Ocean and the GIN Sea form an auto-oscillatory ice-ocean-atmosphere climate system with a quasi-decadal period of interannual variability. The system is characterized by two stages: (1) cold Arctic (ACCR)---warm GIN Sea with weak interaction between the basins; (2) warm Arctic (CCR)---cold GIN Sea with intense interaction between the basins. Surface air temperature and dynamic height gradients between the basins drive the auto-oscillations. This study investigates interactions between the Arctic Ocean and the GIN Sea. To test the hypothesis, a simple model of the Arctic Ocean and Greenland Sea has been developed. The Arctic shelf processes have been parameterized in a box model coupled with an Arctic Ocean module. Both the Arctic Ocean and Greenland Sea modules are coupled with a thermodynamic ice model and atmospheric models. Several model experiments have been conducted to adjust the model and to reproduce the auto-oscillatory behavior of the climate system. One of the major results of this work is the simulation of auto-oscillatory behavior of the Arctic Ocean---GIN Sea climate system. Periodical solutions obtained with seasonally varying forcing for scenarios with high and low interaction between the regions reproduce major anomalies in the ocean thermohaline structure, sea ice volume, and fresh water fluxes attributed to ACCR and CCR regimes. According to the simulation results, the characteristic time scale of the Arctic Ocean---GIN Sea system variability reproduced in the model is about 10--15 years. This outcome is consistent with theory of Proshutinsky and Johnson [1997] and shows that the Arctic Ocean---GIN Sea can be viewed as a unique auto-oscillating system.
    • Deciphering Okmok Volcano's restless years (2002-2005)

      Reyes, Celso Guillermo; McNutt, Stephen; West, Michael; Freymueller, Jeffrey; Larsen, Jessica (2015-08)
      Okmok Volcano is an active island-arc shield volcano located in the central Aleutian islands of Alaska. It is defined by a 10-km-diameter caldera that formed in two cataclysmic eruptions, the most recent being ~2050 years ago. Subsequent eruptions created several cinder cones within the caldera. The youngest of these, Cone A, was the active vent from 1815 through its 1997 eruption. On July 12 2008 Okmok erupted from new vents located northwest of Cone D. Between 2001 and 2004, geodetic measurements showed caldera inflation. These studies suggested that new magma might be entering the system. In 2002, a newly installed seismic network recorded quasi-periodic ("banded") seismic tremor signals occurring at the rate of two or more episodes per hour. This tremor was a near-continuous signal from the day the seismic network was installed. Although the volcano was not erupting, it was clearly in a state of unrest. This unrest garnered considerable attention because the volcano had erupted just six years prior. The seismic tremor potentially held insight as to whether the unrest was a remnant of the 1997 eruption, or whether it signaled a possible rejuvenation of activity and the potential for eruption. To determine the root cause and implications of this remarkable seismic tremor sequence, I created a catalog of over ~17,000 tremor events recorded between 2003 and mid-2005. Tremor patterns evolved on the scale of days, but remained the dominant seismic signal. In order to facilitate the analysis of several years of data I created a MATLAB toolbox, known as "The Waveform Suite". This toolbox made it feasible for me to work with several years of digital data and forego my introductory analyses that were based on paper "helicorder" records. I first attempted to locate the tremor using the relative amplitudes of the seismograms to determine where the tremor was being created. Candidate tremor locations were constrained to a few locations along a corridor between Cone A and the caldera center. I then determined theoretical ratios between a reference station and stations nearby the candidate sources. Results suggested that the signal originated in the shallow portion of the corridor connecting the surface of Cone A to the top of the central magma chamber. This study also suggested that the source migrated along this corridor. I integrated the tremor patterns with other studies and proposed that heat and pressure from continued injections of magma were responsible for maintaining an open venting system at Cone A. The tremor resulted from the boiling of a shallow hydrothermal system in the vicinity of Cone A and volatiles potentially coming from the magma itself. The tremor catalog demonstrates that the seismic signal waned during the study period suggesting that fewer fresh volatiles entered the system, which may have allowed the pathways connecting the magma and volatiles to the surface to close up. By the time new magma entered the system in 2006, this network of pathways was closed, forcing the volatiles to seek a new exit. In hindsight, the 2003-2005 period of varied and waning seismic tremor, and the inferred end of massive open venting, may have been a pivotal era at Okmok that eventually led to the 2008 eruption.
    • The decision-making process of first year teachers

      Coskey, Isabeau S. (2015-08)
      Attrition rates among beginning teachers have long been a cause for concern. As a profession, teaching is one that is extremely difficult to enter into and find your footing. For most novice teachers the first year of teaching is typically the most difficult due to the challenges faced both in the classroom and personally. During the day a myriad of decisions fall on the shoulders of a teacher and long after students have gone most teachers are continuing to make decisions about the classroom. This project examines the major areas where decisions are being made, charts the decision-making process first year teachers employ, and presents an electronic guidebook that can be used by individuals transitioning from a pre-service program into their first year of teaching.