• Local scale structures in earth's thermospheric winds and their consequences for wind driven transport

      Dhadly, Manbharat Singh; Conde, Mark; Collins, Richard; Olson, John; Hampton, Donald; Smith, Roger (2015-12)
      In the traditional picture of Earth's upper thermosphere (~190-300 km), it is widely presumed that its convective stability and enormous kinematic viscosity attenuate wind gradients, and hence smooth out any structure present in the wind over scale size of several hundreds of kilometers. However, several independent experimental studies have shown that observed upper thermospheric wind fields at high latitudes contain stronger than expected local-scale spatial structures. The motivation of this dissertation is to investigate how the resulting local-scale gradients would distort neutral air masses and complicate thermospheric wind transport. To achieve this goal, we examined the behavior of a simple parameter that we refer to as the "distortion gradient". It incorporates all of the wind field's departures from uniformity, and is thus capable of representing all resulting contributions to the distortion or mixing of air masses. Climatological analysis of the distortion gradient using 2010, 2011, and 2012 wind data from the All-sky Scanning Doppler Imager (SDI) located at Poker Flat (65.12N, 147.47W) revealed the diurnal and seasonal trends in distortion of thermospheric masses. Distortion was observed to be dependent on geomagnetic activity and orientation of the interplanetary magnetic field. To understand the time-cumulative influence of these local-scale non-uniformities on thermospheric wind driven transport, time-resolved two-dimensional maps of the thermospheric vector wind fields were used to infer forward and backward air parcel trajectories. Tracing air parcel trajectories through a given geographic location indicates where they came from previously, and where they will go in the future. Results show that wind driven transport is very sensitive to small-scale details of the wind field. Any local-scale spatial wind gradients can significantly complicate air parcel trajectories. Transport of thermospheric neutral species in the presence of the local-scale wind gradients that we observed was found to be far more complicated than what current models typically predict. To validate these findings, we cross-compared the upper thermospheric neutral winds inferred from a narrow field of view Fabry-Perot interferometer with winds measured by our all-sky SDI. A high degree of correlation was present between their measurements. This cross-validation study suggests the presence of small-scale short-lived, and previously unobserved wind features in the upper thermosphere, with typical length scales less than ~40 km. The spatially and temporally localized wind features implied by this study represent a new and unexplored regime of dynamics in the thermosphere.
    • Local trapping as predator control in rural Alaska: limiting factors in Allakaket and Alatna and the potential for increased community involvement in wildlife management

      Hatcher, Heidi L; Fix, Peler; Koskey, Michael; Kielland, Knut; Stout, Glenn (2013-08)
      For a community to be involved in natural resources management that community must have the capacity to make management actions. The capacity for a community to be involved in natural resources management or to take management action might be dependent on a wide variety of factors, largely based upon the resource and asset base available to a community. Aerial wolf control as a wildlife management strategy in the state of Alaska is a controversial endeavor. In the rural villages of Allakaket and Alatna wolf trapping was traditionally a commonly practiced subsistence activity but local levels of wolf trapping are currently very low. The State of Alaska began performing aerial wolf control around Allakaket and Alatna in February 2013 per the request of local residents but the program took more than a decade to come to fruition. To investigate the factors that have led to the decline in local wolf trapping in Allakaket and Alatna and to determine if local trapping could be increased as a means of predator control this study adopted a modified analytic induction methodology. Four propositions and hypotheses were developed regarding the decline in local trapping and the potential to increase local wolf trapping. The propositions and hypotheses were based on the ideas that 1) a community must possess the capacity to take action in order to do so, 2) The benefits of action must outweigh the costs, 3 ) local norms and values must support an action for it to occur, and 4) management roles, responsibilities, and power-dynamics between communities and management agencies can affect the action of a community. Semi-structured interviews were conducted with 16 residents of Allakaket and Alatna to gather data relevant to the propositions and hypotheses. A codebook was developed and Randolph's Free-Marginal Multirater Kappa was calculated with acceptable levels of inter-coder reliability resulting for each code (k >̲ .80). Codes were used to organize data from each interview, which were then used to test the hypotheses. Local norms and values do not appear to be limiting local trapping, the community recognizes the benefits of local trapping to outweigh the costs, and the community also recognizes itself to have a responsibility to take management action, so management power dynamics do not appear to be limiting trapping. The community may not have the full capacity to increase local trapping as a form of local wolf control, as the resources or motivation to organize an increase in local trapping are not being realized within the community. Furthermore, a generation gap was identified that appears to be limiting the ability of the community to connect potential trapping students with teachers to revive and perpetuate the local tradition of trapping.
    • Localization of Francisella pathogenicity island-encoded secreted proteins and their secretion system

      Hare, Rebekah Frances; Hueffer, Karsten; Taylor, Barbara; Duffy, Larry (2014-05)
      Intracellular pathogens have evolved virulence genes that allow them to exploit host cells for their life cycles, and virulence genes are commonly located in pathogenicity islands, such as the Francisella pathogenicity island of Francisella tularensis. The Francisella pathogenicity island is linked to virulence, intracellular growth, and a type VI secretion system. Since the Francisella pathogenicity island encodes a secretion system, I hypothesize that Francisella pathogenicity island encoded proteins are secreted during infection of host cells. The molecular mechanisms involved in the pathogenesis of this bacterium are not well understood and there are no readily available tools for studying these mechanisms. Therefore, I developed expression plasmids of all Francisella pathogenicity island encoded proteins as C-terminal and N-terminal epitope FLAG-tagged proteins. The Francisella pathogenicity island encoded proteins expressed from these plasmids successfully restored the intramacrophage growth phenotype in mutants of their respective genes that were deficient for intramacrophage growth. Immuno-fluorescence microscopy experiments of cells infected with bacteria containing the expression plasmids showed some of the Francisella pathogenicity island encoded proteins were secreted. To test if protein localization is dependent on the type VI secretion system, localization observed in wild type was compared to the localization of Francisella pathogenicity island encoded proteins in a pdpB mutant, a gene that is homologous to a type VI secretion system structural inner membrane protein. The localization of FLAG-tagged proteins was significantly reduced when expressed in the pdpB mutant compared to expression in wild type. Two of the secreted proteins, pdpC and pdpE, were tested for their roles in pathogenicity. pdpC was required for virulence in vivo but not for growth within macrophages. Plasmid expression of PdpC-FLAG and FLAG-PdpC in the pdpC mutant restored the virulent phenotype to that of the wild type. PdpE was not required for intramacrophage growth or virulence in mice. These data further support the hypothesis that the Francisella pathogenicity island encodes a secretome that contributes to the virulence of Francisella.
    • Long term evaporation pan data to estimate potential evaporation during the warm season on the Alaskan North Slope: Imnavait Creek basin

      Mumm, John Paul; Kane, Douglas L.; Toniolo, Horacio; Schnabel, William (2017-12)
      Evapotranspiration plays a significant role in the hydrologic cycle of all basins, yet is only ccasionally measured in the Arctic. One simple index method to evaluate evapotranspiration is the evaporation pan. The energy environment surrounding the simple evaporation pan varies considerably from that of the natural environment. Yet, an evaporation pan is a sound way to determine and estimate the potential evapotranspiration, and actual evapotranspiration can be estimated from evaporation pan data by determining and employing a pan coefficient. An evaporation pan was initially installed in 1986 in the northern foothills of the Brooks Range on the North Slope of Alaska in Imnavait Creek Basin, collecting data for 22 years. The total summer maximum, average, minimum and standard deviation of pan evaporation were 34.9 cm, 29.9 cm, 19.7 cm and 9.3 cm, respectively from 1986 to 2008 (1989 missing). Both, the seasonal water balance and the Priestley-Taylor method for the 2.2 km² Imnavait Creek catchment were used to produce seasonal estimates of actual evapotranspiration. When used in conjunction with the evaporation pan measurements, an average pan coefficient of 0.58 was found in both cases, which was very similar to what was found in an earlier study on Imnavait Creek Basin. The evaporation pan results can also be correlated effectively with other measured variables (such as thawing degree days, air temperature, net radiation, vapor pressure deficit, precipitation, wind speed, and wind direction); this is a method that allows one to predict potential evapotranspiration in areas where it is not measured at broader spatial scales.
    • Long-Period Seismicity At Shishaldin Volcano, Alaska

      Petersen, Tanja; McNutt, Stephen R. (2006)
      Since it last erupted in 1999, Shishaldin Volcano, Aleutian Islands, Alaska, has been characterized by a continuous and extremely high level of seismicity. The activity consists of many hundreds to thousands long-period (LP; 1-2 Hz) earthquakes per day. The rate of one LP event every 0.5-5 minutes has remained more or less constant for the last 7 years. A high rate of LP seismicity has been associated with pre-eruptive activity at many other volcanoes presented in the volcano seismology literature. Shishaldin, however, shows no other signs of volcanic unrest except for a ~200 m high steam plume that nearly always emanates from the volcano's summit and occasional weak thermal anomalies observed in satellite imagery. This thesis investigates the nature of Shishaldin's unusual volcanic behavior, and provides a case-study that mainly focuses on seismic data recorded by the short-period monitoring network surrounding the volcano, but also integrates local infrasound data, visual observations and SO2 measurements. The observations suggest a steady-state volcanic process within an open conduit system that is capable of releasing a large amount of energy, approximately equivalent to at least one magnitude 1.8-2.6 earthquake per clay. Shishaldin infrasound signals recorded by a pressure sensor co-located with a seismic instrument are used to confine the source locations of the LP events to a depth of 240 +/- 200 m below the crater rim. The seismo-acoustic data suggest that the LP earthquakes are associated with degassing explosions, created by complex gas volume ruptures from a fluid-air interface. Measurements of the SO2 flux within the puffing summit plume have revealed low values (58 tons/day), suggestive of a hydrothermal system. Four time periods of increased earthquake amplitudes, which each lasted about 1-2 months; have been analyzed. The periods of elevated seismicity are characterized by an abundance of LP events with highly similar waveforms that represent a spatially confined, repetitive, and non-destructive source process. A mechanism, known as choked flow, fulfills all the requirements implied by the observed repeating events and provides a plausible trigger mechanism for Shishaldin's LP events. The observations suggest that the hydrothermal system at Shishaldin is multi-fractured, regulating a pressure gradient within the gas flow through the uppermost conduit.
    • Long-term monitoring of geodynamic surface deformation using SAR interferometry

      Gong, Wenyu; 龚文瑜; Meyer, Franz; Atwood, Donald; Freymueller, Jeff; Lu, Zhong; Webley, Peter (2014-05)
      Synthetic Aperture Radar Interferometry (InSAR) is a powerful tool to measure surface deformation and is well suited for surveying active volcanoes using historical and existing satellites. However, the value and applicability of InSAR for geodynamic monitoring problems is limited by the influence of temporal decorrelation and electromagnetic path delay variations in the atmosphere, both of which reduce the sensitivity and accuracy of the technique. The aim of this PhD thesis research is: how to optimize the quantity and quality of deformation signals extracted from InSAR stacks that contain only a low number of images in order to facilitate volcano monitoring and the study of their geophysical signatures. In particular, the focus is on methods of mitigating atmospheric artifacts in interferograms by combining time-series InSAR techniques and external atmospheric delay maps derived by Numerical Weather Prediction (NWP) models. In the first chapter of the thesis, the potential of the NWP Weather Research & Forecasting (WRF) model for InSAR data correction has been studied extensively. Forecasted atmospheric delays derived from operational High Resolution Rapid Refresh for the Alaska region (HRRRAK) products have been compared to radiosonding measurements in the first chapter. The result suggests that the HRRR-AK operational products are a good data source for correcting atmospheric delays in spaceborne geodetic radar observations, if the geophysical signal to be observed is larger than 20 mm. In the second chapter, an advanced method for integrating NWP products into the time series InSAR workflow is developed. The efficiency of the algorithm is tested via simulated data experiments, which demonstrate the method outperforms other more conventional methods. In Chapter 3, a geophysical case study is performed by applying the developed algorithm to the active volcanoes of Unimak Island Alaska (Westdahl, Fisher and Shishaldin) for long term volcano deformation monitoring. The volcano source location at Westdahl is determined to be approx. 7 km below sea level and approx. 3.5 km north of the Westdahl peak. This study demonstrates that Fisher caldera has had continuous subsidence over more than 10 years and there is no evident deformation signal around Shishaldin peak.
    • Longitudinal distribution patterns and habitat associations of juvenile coho salmon Oncorhynchus kisutch in tributaries of the Little Susitna River, Alaska

      Foley, Kevin Michael; Rosenberger, Amanda E.; Gerkin, Jonathon; Verbyla, David L.; Mueter, Franz J. (2014-05)
      Understanding how headwater streams function as rearing habitats for juvenile coho salmon Oncorhynchus kisutch is essential for effective population management and conservation. To inform habitat restoration activities within the Matanuska-Susitna Valley, Alaska, I determined upstream distribution limits, validated abundance estimates, and established fish habitat relationships in two headwater stream tributaries of the Little Susitna River in 2010-11. Using a low-effort, spatially continuous sampling approach and linear mixed-effects models, I related local- and landscape-scale habitat associations to abundance estimates. All-aged coho salmon composed approximately 98% of all fish sampled and inhabited the entire stream length to their upstream limits. Age-1+ fish resided in 64% and 44% of the stream length for the two sampled streams. The mean upstream elevation limit for all-aged fish in these streams was 278m and 267m. For age- 1+ fish, the upstream elevation limit in the two streams was 275m and 238m. Percent slope at the distribution limit of all-aged fish was consistent across streams at 5%, whereas percent slope for age-1+ fish correspond to 4% and 6%. Elevation and percent slope consistently described upstream distribution limits among age classes. Therefore, we must consider these landscape features when prioritizing restoration projects in headwater streams.
    • Longwave Radiative Transfer In The Atmosphere: Model Development And Applications

      Delamere, Jennifer Simmons; Stamnes, Knut H. (2003)
      A FLexible Radiative Transfer Tool (FLRTT) has been developed to facilitate the construction of longwave, correlated k-distribution, radiative transfer models. The correlated k-distribution method is a technique which accelerates calculations of radiances, fluxes, and cooling rates in inhomogeneous atmospheres; therefore, correlated k-distribution models are appropriate for simulations of satellite radiances and inclusion into general circulation models. FLRTT was used to build two new rapid radiative transfer models, RRTM_HIRS and RRTM_v3.0, which maintain accuracy comparable to the line-by-line radiative transfer model LBLRTM. Iacono et al. [2003] evaluated upper tropospheric water vapor (UTWV) simulated by the National Center for Atmospheric Research Community Climate Model, CCM3, by comparing modeled, clear-sky brightness-temperatures to those observed from space by the High-resolution Radiation Sounder (HIRS). CCM3 was modified to utilize the rapid radiative transfer model RRTM and the separate satellite-radiance module, RRTM_HIRS, which calculates brightness temperatures in two HIRS channels. By incorporating these accurate radiative transfer models into CCM3, the longwave radiative transfer calculations have been removed as a significant source of error in the simulations. An important result of this study is that CCM3 exhibits moist and dry discrepancies in UTWV of 50% in particular climatic regions, which may be attributed to errors in the CCM3 dynamical schemes. RRTM_v3.0, an update of RRTM, is a rapid longwave radiative transfer appropriate for use in general circulation models. Fluxes calculated by RRTM_v3.0 agree with those computed by the LBLRTM to within 1.0 W/m2 at all levels, and the computed cooling rates agree to within 0.1 K/day and 0.3 K/day in the troposphere and stratosphere, respectively. This thesis also assessed and improved the modeling of clear-sky, longwave radiative fluxes at the Atmospheric Radiation Measurement Program North Slope of Alaska site by simultaneously addressing the specification of the atmosphere, radiometric measurements, and radiative transfer modeling. Consistent with findings from other field sites, the specification of the atmospheric water vapor is found to be a large source of uncertainty in modeled radiances and fluxes. Improvements in the specification of carbon dioxide optical depths within LBLRTM resulted, in part, from this analysis.
    • The looking glass effect: the influences of clinical supervision on student attitudes toward evidence based practices

      Leonard, Hugh D.; Campbell, Kendra; Rivkin, Inna; Gonzales, Vivian M.; Fitterling, Jim (2019-08)
      The current study explored how graduate students' attitudes toward evidence-based practices (EBPs) are influenced through clinical supervision. Despite being widely endorsed by professional entities, such as the American Psychological Association, members of the profession have mixed attitudes toward the EBP approach. Mixed attitudes toward EBPs have potentially detrimental effects, such as resulting in clinicians simply dismissing the notion of evidence-based treatment decision making and instead utilizing interventions that are without scientific support and potentially ineffective and even harmful. Resistance toward EBPs has been studied, but largely unstudied is how negative attitudes toward EBPs are developed and propagated to others. Professional identity solidifies in graduate school by way of clinical supervision. The goal of this study was to illuminate underlying influences of clinical supervision on graduate student attitudes toward EBPs, as clinical supervision may be the root cause of resistance toward EBPs. Perceived supervisor credibility influences professional identity development and may be influenced by a positive supervisory working alliance, theoretical orientation match, and overall acquiescence to a clinical supervisor; and these factors may affect attitudes toward EBPs. However, no previous research exists to directly confirm this notion. This study sampled from Ph.D. and Psy.D. clinical psychology graduate students who had started seeing patients (n = 157). Participants completed an online survey battery measuring perceived supervisor credibility, supervisory working alliance, student attitudes toward EBPs, perceived supervisor attitudes toward EBPs, and dispositional psychological reactance. It was predicted that students would perceive their supervisor as credible when their theoretical orientations matched, a positive supervisory working alliance existed, and students' psychological reactance was low. It was also predicted that supervisor attitudes toward EBPs would predict student attitudes toward EBPs when perceived supervisor credibility is high, students' dispositional psychological reactance is low, supervisory alliance is high, and theoretical orientations matched. Simultaneous linear regression and hierarchical regression was used to test the study hypotheses. The results partially supported the study hypotheses. It was found that a positive supervisory alliance predicted perceived supervised credibility. However, the remaining hypotheses were unsupported. Results contribute to the sparse research base on supervisor credibility in that preliminary support is provided that perceived credibility occurs when students and supervisors have a good relationship. Noteworthy are that results yielded from correlations suggested that students' global appreciation for research was related to theoretical orientation match of their clinical supervisor, supervisors' and graduate program's favorable attitudes toward EBP's, and to multi-faceted supervisory relationships such as having a clinical supervisor also as a research supervisor. These findings suggest that student internalization of supervisor attitudes may have less to do with perceived credibility and more to do with attitudes toward research. Future research should consider exploring attitudes toward research in the context of development of attitudes toward EBPs.
    • Losing Ground: An Ethnography Of Vulnerability And Climate Change In Shishmaref, Alaska

      Marino, Elizabeth K.; Schweitzer, Peter (2012)
      This dissertation presents an ethnography of vulnerability in Shishmaref, Alaska. The village of Shishmaref, population 563, faces imminent threat from increasing erosion and flooding events -- linked to climatic changes and ecological shift -- making the relocation of residents off of the island necessary in the foreseeable future. In spite of ongoing conversations with government agencies since 1974, an organized relocation has yet to occur in Shishmaref. While ecological shift and anthropogenic climate change are no doubt occurring in and around the island, the literature on vulnerability and disaster predicts that social systems contribute at least as much as ecological circumstances to disaster scenarios. This research tests this theory and asks the question: what exactly is causing vulnerability in Shishmaref, Alaska? The resulting dissertation is an exploration of the ecological, historical, social and cultural influences that contribute to vulnerability and risk in Shishmaref. Unlike common representations of climate change and disaster that present the natural environment as a sole driver of risk, this research finds complex systems of decision-making, ideologies of development, and cultural assumptions about social life contribute to why Shishmaref residents are exposed to erosion and flooding and why government intervention and planning remains difficult.
    • The low back vowel in mid-coast Maine

      Davidson, Gail (2011-05)
      In mid-coast Maine, the words cod and caught sound like they contain the same vowel phoneme, employing the sound [a], a low back vowel. The word father contains a separate contrasting phoneme, spoken as [a], a low central vowel. This paper attempts to show that this perceived similarity in [a] and difference from [a] is in fact real. Unlike in the area of the Northern Cities Chain Shift, where the sound of the vowels in cod, caught and father all approach [a], the vowel in cod and caught in mid coast Maine remains low and back, occasionally rounded, more often not, while that in father is low and central. Twenty-six current speakers of varying ages, most residents since early childhood, were interviewed to compare these sounds. Each speaker was recorded reading a prepared story and a set of words included in a frame sentence. Formant frequencies for this recorded data were then analyzed. Statistical tests, including t-tests and ANOVAs, were run to compare the vowels and to test the validity of the hypothesis. Normalizing the data for one single vowel sound proved to be unworkable, so men and women were treated separately, as were Narrative and Frame data. The low back vowel was found to be stable in mid-coast Maine, including the same sound in cod and caught, and it was found to contrast with the low central vowel in father. Available historical evidence points to these vowels having been stable in this region for over a hundred years. This contrasts with changes in the vowel sound in the same words in the rest of the United States.
    • Low frequency shelf current fluctuations in the Gulf of Alaska

      Worley, Steven James (1977-08)
      A general oceanographic study of a shelf region in the Gulf of Alaska has revealed low-frequency, current fluctuations. A current meter mooring was located approximately 20 km offshore, in a water depth of 100 m. The time dependent flow is found to be baroclinic and semi-periodic. The effects of local bottom topography, nearshore dilution by river discharge, orographic coastal features, and an island barrier are important to the shelf circulation in this region. The movement of a boundary associated with the Copper River appears to be an important process in controlling the water motion at the mooring site.
    • Low salinity water alternate gas injection process for Alaskan viscous oil EOR

      Saxena, Kushagra; Ahmadi, Mohabbat; Patil, Shirish; Dandekar, Abhijit; Brugman, Robert; Zhang, Yin (2017-05)
      Carbon dioxide has excellent oil swelling and viscosity reducing characteristics. CO₂ injection alternated with water has shown substantial incremental recovery over waterflood for the Alaska North Slope (ANS) viscous oil reservoirs. However, for any project, the ultimate CO₂ slug size is finite and once the apportioned solvent volume is used up, the reservoir oil rates gradually revert to the low waterflood rates during the later life of a field. Low salinity waterflooding (LSWF) has also shown some promise based on corefloods and single well tracer tests in North Slope light oil reservoirs. However, two challenges impede its implementation as a standalone enhanced oil recovery (EOR) option on the North Slope: 1) slow response; the delay prolonged with increasing oil viscosity and 2) large upfront investments for the processing and transport of source water. This study proposes a hybrid EOR scheme, the low salinity water alternate gas (LSWAG) process, for the viscous fields of the ANS. The process was modeled by coupling geochemical and ion exchange reactions to a CO₂-WAG type pattern model of the Schrader Bluff O sand. The Schrader Bluff reservoir has been classified suitable for low salinity EOR based on its permeability, temperature, clay content, and oil and formation water properties. Oil recovery through wettability alteration was modeled through ion exchange at the clay sites. Multiphase compositional flow simulation was run using numerical dispersion control. LSWAG forecast for 50 years following 36 years of high salinity waterflood recovered 15% OOIP more oil over high salinity waterflood and 4% incremental over high salinity WAG. This translates to an improvement of 58% and 11% over waterflood and conventional WAG respectively. Higher oil rates were observed during later life due to increased oil relative permeability caused by the low salinity mechanism. Furthermore, very low solvent utilization values were seen for LSWAG which can be tied to the higher ultimate oil recovery potential of using low salinity water over conventional waterflood. In summary, LSWAG outperformed LSWF and conventional WAG by synthesizing the oil swelling and viscosity reduction advantages of CO₂ with lower residual oil benefits of LSWF, while overcoming the challenges of the late response of LSWF and low waterflood oil rates during later life in a conventional WAG flood.
    • Low-rank high-volatile matter sub-bituminous coal grinding versus power plant performance

      Malav, Dinesh Kumar; Bandopadhyay, Sukumar; Wilson, Terril (Ted); Ganguli, Rajive (2005-08)
      The objective of this project was to determine if the power plant performance, characterized by megawatt and steam generation, is reduced when particle size distribution (PSD) of pulverized-coal fed into the burners is made slightly coarser. Tests were conducted in two phases at a Golden Valley Electric Association power plant. During the first phase, two tests were conducted at significantly different PSDs. Results indicated that coarser distribution did not hurt plant performance. Later, the second phase was carried out to test the repeatability of the observed combustion behavior as well as to test hypotheses on mill power consumption, emissions and unburned carbon. Unfortunately, the three tests in this phase did not result in statistically different PSD's, precluding any conclusions on the main objective. Therefore, further tests are needed to establish the effect of coarser PSD on power plant performance, emissions, unburned carbon and mill power consumption.
    • Lower Tanana Athabascan verb paradigms

      Urschel, Janna Mercedes (2006-05)
      This thesis presents documentation of verb paradigms in the Minto-Nenana dialect of the Lower Tanana Athabascan language, based on fieldwork with four native speakers of the language. Lower Tanana is a severely endangered language spoken in the Interior region of Alaska. The paradigms document the combinations of five Athabascan verb prefixes: classifier, subject, mode, conjugation, and negation. Introductory material describes the Lower Tanana language and outlines the grammar of Lower Tanana verbs, with reference to properties of verbs exemplified in the paradigms. These introductory sections are addressed to teachers and learners of the Lower Tanana language, that they might make optimal use of this thesis as a reference tool in language revitalization efforts.
    • Lower Tanana flashcards

      Dougherty, Summer; Holton, Gary; Ehrlander, Mary E.; McCartney, Leslie (2019-05)
      As part of a study of Lower Tanana, I found it expedient to create a learning tool to help myself gain familiarity with Lower Tanana. I chose to employ Anki, an open-source tool for creating digital flashcard based learning tools. With Anki, I created cards for individual Lower Tanana words and phrases. In producing the computer flashcards for Lower Tanana, I realized that they could serve as a highly flexible system for both preserving and learning Lower Tanana. Further, because of the built-in system flexibility, such systems can be created to aid in preserving and teaching other endangered languages.
    • Lung breathing in the bullfrog: generating respiratory rhythm and pattern

      Davies, Brittany L. (2008-08)
      This research investigated location of the lung respiratory rhythm generator (RRG) in the bullfrog brainstem using neurokinin-1 (NK1R) and [mu]opioid ([mu]OR) receptor colocalization and characterized the role of these receptors in breathing pattern formation. colocalization was distinct near the facial nucleus in juvenile bullfrogs but not in tadpoles. NK1R intensity exhibited no developmental change, while [mu]OR intensity increased from late-stage tadpoles to juvenile frogs. Substance P (NK1R agonist; bath applied) increased lung burst frequency, lung burst cycle frequency (BCF), episode frequency, lung burst amplitude and area, but decreased number of lung bursts per episode and lung burst duration. Antagonist D decreased lung burst frequency and BCF, episode frequency, and the number of lung bursts per episode, and increased lung burst duration and area. DAMGO ([mu]OR agonist; bath applied) decreased lung burst frequency and BCF, episode frequency, and number of lung bursts per episode, but increased all lung burst parameters. Naloxone ([mu]OR antagonist) increased lung burst frequency and BCF, episode frequency, lung bursts per episode but decreased all lung burst parameters. Together these results indicate that NK1R and [mu]OR colocalization represents the lung RRG, and that episode formation is intrinsic to the respiratory control network but may or may not originate in the RRG.
    • Lynx And Coyote Diet And Habitat Relationships During A Low Hare Population On The Kenai Peninsula, Alaska

      Staples, Winthrop R., Iii; Dean, Frederick C. (1995)
      Food habits and habitat use of lynx and coyote were compared 1987-1991 on the Kenai Peninsula, Alaska when the snowshoe hare population was low ($<$0.5 hares/ha). During snow seasons, lynx fed primarily on hares (64% total items), whereas coyotes relied heavily on moose carcasses (42% total items). Diet overlap was 42% and hare use overlap was 16%. Habitat use overlap was 92%, but coyotes used roads more than lynx. Both carnivores selected 1947 burn and avoided 1969 burn and large expanses of mature forest. I conclude that there was exploitation competition for food between these predators, because both used the same habitats and hares, a major food, were scarce. The coyote, however, may be using resources that were previously used by red fox, which have been reduced to low levels. Lynx displayed little fear of humans and were vulnerable to shooting incidental to hunting and depredation events. <p>