• Recommendations for training of substitute teachers in the Matanuska-Susitna Borough School District

      Chamblee, Lulu R.; Topkok, Sean; Hornig, Joan; Kardash, Diane (2020-12)
      With increasing importance placed on student growth and achievement scores, increasing teacher absenteeism, and increasing amounts of time students spend being taught by substitute teachers, it is surprising that the preparation of substitute teachers does not reflect the significance of the job they have in relation to these trends. Research shows that training can increase substitute teacher effectiveness, which may positively affect student growth and achievement. The purpose of this project was to determine what the substitute teacher onboarding process was, including employment requirements and required training, for substitute teachers in the Matanuska-Susitna Borough School District and to make recommendations to the district for the training of substitute teachers. Substitute teachers in the district were asked to complete a survey regarding their experience, current level of training, and perceived training needs. I found that regardless of the amount of experience and training substitute teachers already possess, they want more training not only in the programs and initiatives utilized by the district, but also in effective instructional strategies, best practices, and teaching methods in curricular areas. While the district onboarding process is fairly comprehensive, as is the available optional training, I developed recommendations to improve the onboarding process and training options for substitute teachers in the district to strengthen substitute teacher effectiveness.
    • Reconstruction Of Neets'Aii Gwich'In Land Use: A Methodological Study.

      Peirce, John Carl, Jr. (1995)
      This thesis attempts to determine to what extent land use patterns for the Neets'aii Gwich'in of Alaska can be spatially reconstructed from existing sources. Written narratives are reviewed, such as those related by explorers, missionaries, traders and prospectors, for information on land use. Also reviewed are data that give a broad array of subsistence, demographic, geographical or other relevant information concerning land use, including biological and geological reports, economic studies, census reports, Neets'aii Gwich'in oral narratives, archaeological studies, ethnographic studies, place name studies and maps, and land use and occupancy studies. Methodological models for gathering land use data are reviewed to establish a foundation from which the land use data discussed in this thesis can be compared. Finally, an analysis of the extent to which Neets'aii Gwich'in land use can be reconstructed using historic sources is applied to various conceptual levels of understanding Northern hunter and gatherer land use. <p>
    • A reconstruction of steppe bison mobility in the Yukon-Tanana uplands and implications for prehistoric human behavior

      Glassburn, Crystal L.; Clark, Jamie L.; Potter, Ben A.; Reuther, Joshua D.; Wooller, Matthew J. (2015-08)
      This study seeks to characterize steppe bison (Bison priscus) behavioral ecology in interior Alaska during the Pleistocene for the purpose of understanding how bison may have moved about the landscape on a seasonal basis and how this behavior could have influenced prehistoric human settlement and subsistence patterns. Steppe bison were present in Alaska and other circumpolar regions during the Pleistocene but became extinct during the late Holocene. Archaeological evidence from the Tanana River Basin in interior Alaska indicates that bison were an important component of human subsistence economies for at least 10,000 years, but aspects of steppe bison behavioral ecology including location of habitat area, seasonal movement patterns, and responses to environmental change remain largely unexplored in Alaskan archaeology or paleoecology. This study applies strontium, oxygen, and carbon isotopic analyses to 14 sequentially-sampled and AMS radiocarbon dated steppe bison teeth from two locales in the Yukon-Tanana Uplands in order to reconstruct steppe bison behavior on a seasonal basis. This study is the first of its kind for any prehistoric species in Alaska, and the results indicate that steppe bison did not migrate great distances, but instead, moved between different ecotones seasonally, spending summers in higher elevation regions and winters in lower elevation regions. The results also indicate that steppe bison had greater mobility during periods of warmer climate, including Marine Isotope Stage 3 (MIS3) and during the Late Pleistocene. Bison would have represented a large-bodied and predictable source of food for prehistoric peoples, and these results suggest that human landuse patterns likely incorporated the use of upland regions during the summer and fall, and lowland regions during the winter and early spring. Additionally, the results suggest that bison movement on the landscape would have been more predictable during the Late Pleistocene than during the Holocene. As such, settlement and subsistence patterns may have shifted from a more residentially-organized pattern during the Late Pleistocene to greater logistical mobility during the Holocene as bison population became more mobile.
    • Reconstruction of the damaged central nervous system and spine

      Helm, Gregory Anthony (1996)
      The field of neuronal transplantation has received a great deal of interest since the 1970's and is currently considered a possible treatment option for both neurodegenerative diseases and spinal cord injury. In this dissertation, fetal neostriatal transplants grafted into the lesioned striatum were studied in both the rat and rhesus monkey. Golgi-impregnation and immunohistochemical techniques were extended to the light and electron microscopic levels to determine the detailed anatomy of the developing striatal implants. Choline acetyltransferase immunoreactive and substance P-like immunoreactive neurons within the rat striatal transplants were morphologically and ultrastructurally similar to normal striatal neurons. When the striatal grafting studies were extended into the rhesus monkey, normal neuronal maturation was demonstrated three months postoperative, both at the light and electron microscopic levels, using various neuroanatomical techniques. From these studies it can be concluded that fetal striatal grafts may be a useful treatment option for Huntington's disease, although numerous difficulties including neuronal degeneration and transplant rejection need to be addressed before this approach is applied in the clinical setting. In a second group of experiments, various approaches to improve autologous bone spinal fusions were studied. Specifically, the utilization of demineralized bone matrix, Type I collagen gel, and recombinant human bone morphogenetic proteins were evaluated for their effects on autologous bone spinal fusions in canines. The study demonstrated that recombinant human bone morphogenetic protein has a strong effect on the amount of bone deposition at the fusion site and, in addition, increases the number of vertebral levels which solidly fuse. The Type I collagen gel appeared to improve the interface between the autologous bone grafts and the host bone, while the demineralized bone matrix had a strong negative effect on the autologous bone graft fusions. Spinal fusion operations in the future will be much more successful if these various methods to improve spinal arthrodesis are utilized to their full potential. It is now clear that reconstruction of the central nervous system and its bony coverings is a real possibility in the very near future, although extensive clinical studies need to be performed before they are widely used in the neurosurgery community.
    • Recovery of rare earth elements from Alaskan coal and coal combustion products

      Gupta, Tushar; Ghosh, Tathagata; Akdogan, Guven; Bandopadhyay, Sukumar; Misra, Debasmita (2016-12)
      Owing to the monopolistic supply and rapid demand growth of Rare Earth Elements (REEs), cost effective and eco-friendly technologies for extraction of REEs from coal and coal byproducts are being widely explored. Physical separation tests, like magnetic separation, float-sink and froth flotation, were conducted at a laboratory scale, for identification and characterization of REEs in two Alaskan coal samples. The studies revealed that the samples are enriched in critical REEs, and have elevated REE concentrations as compared to average world coal estimates. The selected coal samples from Healy and Wishbone Hill regions were found to possess an overall concentration of 524 ppm and 286 ppm, respectively, of REEs in coal on ash basis and some density fractions have total REE concentrations as high as 857 ppm. Based on the characterization studies, detailed investigations were conducted to enrich the REEs and produce a concentrate for downstream extraction. A three-factor three-level Box-Behnken design for modeling and optimization of froth flotation revealed that the optimum flotation conditions for maximum REE Enrichment in the froth fraction was independent of collector dosage for both coal samples. The response variable was maximized at 4.2% solids and 32.7 ppm of frother dosage for Healy Coal sample and 10% solids and 37.9 ppm of frother dosage for Wishbone Hill Coal sample. A processing flowsheet for REE enrichment in clean coal is proposed, which aims at concentrating REEs in lower density fractions by a combination of dense medium separation and froth flotation processes. The overall REE recovery of the process is calculated to be 76% for Healy and 60% for Wishbone Hill with clean coal fractions enriched in REE concentrations above the cut-off value required for the commercial exploitation. The coals are bound to possess the potential to be used as a REE resource under favorable socio-economic and geo-political scenarios.
    • Recreation

      Alfaro, Alex; Johnson, Sara Eliza; Reilly, Terence; Brightwell, Gerri (2018-05)
      This collection was the result of a "happy accident" which occured while watching late night tv and writing poetry. It felt odd at the time to be doing something so mundane and contemporary while also creating something as ancient and steeped in culture and tradition. My life has always seemed varied, almost random, and that's the basic premise of this collection. From such randomness do these poems find purpose: from absurdity comes destiny, from insignificance comes enlightenment and everything in between is a just a privilege--but art, that's where this collection can live.
    • Recruitment mechanisms of tanner crab in the eastern Bering Sea

      Richar, Jonathan; Kruse, Gordon; Mueter, Franz; Eckert, Ginny; Zheng, Jie (2014-08)
      Influences of biophysical conditions on survival of zoeal and early stages of eastern Bering Sea Tanner crab, Chionoecetes bairdi, were investigated using simple linear regression modeling, and a combination of hydrodynamic modeling and spatial and geostatistical methods. Linear regression analyses indicated that estimated reproductive female crab abundance, age 3-7 Pacific cod (Gadus macrocephalus) abundance and flathead sole (Hippoglossoides elassodon) total biomass were statistically related to estimates of recruitment to the 30-50 mm carapace width size interval of juvenile crab. Analysis of output from a Regional Ocean Modeling System simulation model indicated considerable capacity of the Bering Sea oceanography to retain zoeae at regional and local scales. Major transport patterns corresponded to long-term mean flows, with a northwesterly vector. Retention may be a significant recruitment process, particularly in Bristol Bay, which is effectively oceanographically isolated from other source regions of crab larvae. Periods during which conditions may have favored juvenile crab survival were observed at the model-estimated larval endpoints during the early 1980s and mid to late 1990s. While environmental conditions at model-estimated endpoints were highly variable, crab recruitment was positively correlated with endpoint locations either within the periphery of the cold pool, or outside of it, and SST >2° C after allowing for autocorrelation in the juvenile recruitment series. However, limitations of the model, gaps in knowledge of Tanner crab life history and ecology, and the possibility of spurious correlations complicate interpretation of these results.
    • Recurrence analysis methods for the classification of nonlinear systems

      Graybill, Mark; Wackerbauer, Renate; Chowdhury, Ataur; Newman, David (2014-05)
      Recurrence is a common phenomenon in natural systems: A system enters and leaves a state, but after a given period of time, passes near that same state again. Many complex signals, such as weather cycles, heartbeats, or neuron firing patterns, all show recurrence. The recurrence plot (RP) displays all times j where a system returns near a state it has occupied at time i, giving rise to upward-sloping diagonal lines where a system follows a recurrent path, orthogonal lines when the system changes very slowly, or many disconnected points where a system's behavior is unpredictable. Investigation of the RP can then proceed through recurrence quantification analysis (RQA). Three new measures for RQA were developed: diagonality, quantifying diagonal lines, verticality, quantifying vertical lines, and periodicity quantifying the arrangement of recurrence points in periodic structures. These new measures were applied alongside classical recurrence measures to explore trends in random data, identify periodicity and chaotic behavior in the logistic map, estimate the dimensionality of the Lorenz attractor, and discriminate between persistent data signals. In collaboration with biologist Dr. Michael Harris, RQA methods were applied to the discrimination of two neuron types: serotonergic cells are believed to stimulate respiration, while nonserotonergic cells are implicated in respiratory inhibition. Typical discrimination methods compare mean and standard deviation of firing rates to a reference line, which correctly classifies serotonergic cells but incorrectly classifies many nonserotonergic cells. Voltage signals from such cells were converted into inter-spike intervals. Convergence required trials containing over 300 spikes for biological methods, and over 1000 for full investigation using RQA. Whether such cells can be discriminated from baseline firing patterns remains an open question.
    • Red King Crab Hatchery Culture And Ecological Requirements: Applications For Stock Enhancement

      Daly, Benjamin J.; Eckert, Ginny; Konar, Brenda; Kruse, Gordon; Stoner, Allan (2012)
      The ecologically and commercially important red king crab (Paralithodes camtschaticus) is depleted throughout much of the North Pacific and thought to be recruitment limited, making it an appropriate candidate for stock enhancement efforts. This research addresses bottlenecks associated with hatchery production and lays the groundwork for developing release strategies. I investigated effects of diet, stocking density, and size grading on survival, growth, and shell coloration of recently-settled juvenile red king crabs in large-scale hatchery experiments. I also conducted laboratory experiments with fish predators to determine if red king crab predator responses could be enhanced with experience. Finally, I tethered hatchery-cultured red king crabs of two sizes in the field for 24 h trials and used underwater video cameras to identify predators and predation susceptibility. In hatchery experiments, dietary astaxanthin supplementation improved survival and shell coloration suggesting that red king crab coloration is plastic and that astaxanthin may provide nutritional or immune system benefits. Size grading strongly influenced survival and growth in the hatchery. Generally, small crabs had higher survival than large and ungraded crabs, but large and ungraded crabs had higher growth, likely from cannibalism. In laboratory experiments, halibut exposure enhanced red king crab crypsis and survival suggesting that cryptic behavior is plastic and may be enhanced with experience. In the field experiment, I identified specific predators of recently-settled red king crabs in a nearshore habitat and showed that survival did not vary with body size or deployment month during the first juvenile instar stages. My research provides an important step for developing a responsible red king crab stock enhancement program by demonstrating that hatchery production can be improved with specific advances in rearing technology, hatchery-cultured red king crabs are morphologically and behaviorally plastic, hatchery-cultured red king crabs tethered in the field show no obvious behavioral deficiencies that may exacerbate predation, and that differences in predation susceptibility during the first juvenile instar stages are subtle and may be ecologically inconsequential for post-release survival. As bottlenecks in hatchery production and survival of released juveniles are overcome, stock enhancement will become increasingly feasible for red king crabs in Alaska.
    • Red squirrel (Tamiasciurus hudsonicus) ecology during spruce cone failure in Alaska

      Smith, Michael C. T. (1967-05)
      Observations were made on a red squirrel (Tamiasciurus hudsonicus) population in a mature white spruce (Picea glauca) forest near Fairbanks, Alaska, during two years of spruce cone crop failure (July, 1964, to April, 1966). An adequate supply of old spruce cones, cached in previous years, was available during the first winter. A 67% drop in numbers of the squirrel population followed the second crop failure with the remaining squirrels utilizing spruce buds as their primary food during the winter. Stomach analyses revealed that when present, spruce seed is the major constituent in the diet. In its absence, heavy utilization of mushrooms in summer and spruce buds in winter occurs. Feeding trials conducted with captive red squirrels in March, 1965, and April, 1966, showed that about 194 old cones per day were necessary to sustain a squirrel, approximately 35% more than for cones from the current year's crop. Three squirrels survived for eight days on a diet of only white spruce buds. Analysis of old spruce cones showed that 31% of the seed was potentially viable (filled), but that only 1.4% of the seed germinated. Calorimetric determinations of old seed (minus coat), spruce buds, and mushrooms yielded values of 5,976, 4,986, and 4,552 cal/g respectively. Excavation of middens revealed up to 8,518 old, cached cones per midden, despite a crop failure. In years of normal cone production, squirrels may cut and cache 12,000 to 16,000 cones; the excess accrues each year and eventually a sufficient supply exists to maintain the squirrels through a winter following a cone crop failure.
    • Refined liquid smoke: a potential antilisterial supplement to cold-smoked sockeye salmon (Oncorhynchus nerka)

      Montazeri Djouybari, Naim; Oliveira, Alexandra; Himelbloom, Brian; Crapo, Charles; Leigh, Mary Beth (2011-12)
      Listeria monocytogenes, the causative agent of listeriosis can contaminate cold smoked salmon (CSS) and make it a high-risk ready-to-eat food product. Due to the lack of a critical control point in the cold-smoking process, a post-process elimination is essential to ensure product safety. The goal of this project was to improve safety of vacuum-packaged CSS supplemented with commercially refined liquid smoke (LS). Gas chromatography-mass spectrometric analysis showed the LS were high in carbonyl containing compounds and low in phenol derivatives. The LS (AM-10 and AM-3) producing the greatest inhibition against L. innocua in a paper disk diffusion assay were applied to the CSS strips at 1% (v/w). The CSS were inoculated with L. innocua, vacuum packaged, and stored at 4°C. Addition of LS imparted a listericidal effect with a 2-log reduction by day 14, and no growth up to 35 days of storage. For the sensory evaluation, AM-3 was selected for its slightly stronger listericidal activity. A simple difference sensory test including 180 untrained assessors showed the overall sensorial quality of CSS was not influenced by the addition of the LS. The present study recommends refined LS as a suitable antilisterial supplement to CSS.
    • Reflections from a hard country

      Jones, Loretto Lee (2007-05)
      This collection of stories is memoir, compiled from my experiences working in Alaska's commercial fishing industry during the 1970s and 1980s. Alaska fishermen have always been considered to have one of the most dangerous occupations, but it was in this era, before rationalization and privatization, that incredible risks were taken. Much has changed the way Alaskans fish now, but these sea stories really happened. Now, almost forty years later, these seven stories have come to print. Each serves as a reminder of that time when being Alaskan meant freedom and taking chances, creating extraordinary men and women who faced uncertainty on a daily basis. The characters were and are real people. I choose not use the last names of my friends in order to respect the identities of the families.
    • Regional climate, federal land management, and the social-ecological resilience of southeastern Alaska

      Beier, Colin Mitchell (2007-08)
      Complex systems of humans and nature often experience rapid and unpredictable change that results in undesirable outcomes for both ecosystems and society. In circumpolar regions, where multiple converging drivers of change are reshaping both human and natural communities, there is uncertainty about future dynamics and the capacity to sustain the important interactions of social-ecological systems in the face of rapid change. This research addresses this uncertainty in the region of Southeast Alaska, where lessons learned from other circumpolar regions may not be applicable because of unique social and ecological conditions. Southeast Alaska contains the most productive and diverse ecosystems at high latitudes and a human population almost entirely isolated and embedded in National Forest lands; these qualities underscore the importance of the region's climate and federal management systems, respectively. This research presents a series of case studies of the drivers, dynamics, and outcomes of change in regional climate and federal management, and theoretically grounds these studies to understand the regional resilience to change. Climate change in Southeast Alaska is investigated with respect to impacts on temperate rainforest ecosystems. Findings suggest that warming is linked to emergence of declining cedar forests in the last century. Dynamics of federal management are investigated in several studies, concerning the origins and outcomes of national conservation policy, the boom-bust history of the regional timber economy, and the factors contributing to the current 'deadlock' in Tongass National Forest management. Synthesis of case study findings suggests both emergent phenomena (yellow-cedar decline) and cyclic dynamics (timber boom-bust) resulting from the convergence of ecological and social drivers of change. Adaptive responses to emergent opportunities appear constrained by inertia in management philosophies. Resilience to timber industry collapse has been variable at local scales, but overall the regional economy has experienced transition while retaining many of its key social-ecological interactions (e.g., subsistence and commercial uses of fish and wildlife). An integrated assessment of regional datasets suggests a high integrity of these interactions, but also identifies critical areas of emergent vulnerability. Overall findings are synthesized to provide policy and management recommendations for supporting regional resilience to future change.
    • Regional distribution, life history, and morphometry of spawning stage Capelin Mallotus villosus

      Ressel, Kirsten N.; Sutton, Trent M.; Bell, Jenefer L.; Seitz, Andrew C. (2019-12)
      Capelin Mallotus villosus is a forage fish that is integral to many Arctic and subarctic marine food webs, but is less thoroughly studied outside the Atlantic Ocean. The goal of this research was to study spawning Capelin in data-poor areas, particularly in waters off the coast of Alaska and the western Canadian Arctic, to enrich baseline data and allude to intraspecies diversity. Chapter one examined the distribution and life history of spawning Capelin in Norton Sound, Alaska, by conducting aerial surveys, collecting sediment samples to characterize beach spawning habitats, and identifying biological attributes of spawners (e.g., body size, age, fecundity, etc.). Chapter two used a geometric morphometric approach (i.e., relative warps) and multiple statistical techniques (i.e., relative warp analysis, Procrustes analysis of variance, estimates of morphological disparity, and canonical variates analysis) to differentiate among and within putative populations of spawning Capelin in the western Canadian Arctic, Newfoundland, Canada, and Alaska. Spawning Capelin in Norton Sound portrayed similar behaviors, occupied similar beach habitats, and encompassed a similar range in biological attributes as fish observed in other regions throughout this species' geographic distribution. However, average spawner body size, age, fecundity, and morphometry differed among regions. These results suggest that Capelin exhibit some similarities in spawning behavior and habitat use across their geographic distribution, but may exhibit population-specific differences in biological attributes among and within regions.
    • Regional modeling of Greenland's outlet glaciers with the parallel ice sheet model

      Della-Giustina, Daniella N. (2011-12)
      The most recent report from the Intergovernmental Panel on Climate Change cites ice sheet dynamics as the greatest source of uncertainty for predicting current and future rates of sea level rise. This has prompted the development and use of ice sheet models that are capable of simulating the flow and evolution of ice sheets and their corresponding sea level contribution. In the Arctic, the Greenland ice sheet appears to be responding to a warming climate more quickly than expected. In order to determine sea level contribution from Greenland, it is necessary to capture the regional dynamics of the fast flowing outlet glaciers that drain the ice sheet. This work has developed a novel regional model capable of simulating an outlet glacier, and its associated drainage basin, as a mode of using the Parallel Ice Sheet Model. Specifically, it focuses on modeling the Jakobshavn Isbrae as a demonstration. The Jakobshavn Isbrae is one of the world's fastest flowing outlet glaciers, and accounts for nearly 5% of ice loss from the Greenland Ice Sheet. Additionally, the Jakobshavn Isbrae has been widely studied for several decades, and a wealth of remotely sensed and in situ data is available in this region. These data are used as model input and for model validation. We have completed a parameter study in this work to examine the behavior of the regional model. The purpose of this study was not to tune the model to match observations, but rather to look at the influence of parameter choices on the ice dynamics. Model results indicate that we have identified the subset of the model parameter space that is appropriate for modeling this outlet glacier. Additionally, we are able to produce some of this more interesting features that have been observed at Jakobshavn, such as the development and disintegration of a floating ice tongue and the distribution of observed surface velocities. We validate these model results by comparison with recent spatially rich measurements of ice surface speeds, as well as ice geometry.
    • Regional variation in mandibular morphology in the prehistoric Japanese populations of the Jōmon and Okhotsk

      Arenas, Rogelio A. (2012-08)
      Examination of 11 metric mandibular traits was conducted on data collected from several Jōmon and Okhotsk sites for the purpose of analyzing potential impacts of dietary differences on mandibular morphology for these groups. Based on the dietary history of the populations and their respective regions, Middle Jōmon (5,000 - 3,000 BP) sites would share comparable robusticities across all regions based on social and economic continuity as a stable climate resulted in abundant dietary resources which fostered a growth in population in the Japanese islands of Honshu and Hokkaido. As the climate cooled in the Late/Final Jōmon (4,000 - 2,000 BP), the population of the two islands crashed coinciding with reduced carrying capacity of the environment due to a reduction in available food resources. Late/Final Jōmon were expected to show mandibular reduction in the Honshu interior which had engaged in plant cultivation and emergent agriculture as opposed to populations on the Hokkaido and Honshu coast which engaged in marine subsistence. The success of agriculture resulted in an expansion across Honshu, pushing marine subsistence communities northeastward to Hokkaido where the tradition persisted as the Epi-Jōmon until the arrival of immigrant populations of the Okhotsk (1,000-600 BP). The Epi-Jōmon and Okhotsk would share comparable robuticities based on their shared practice of marine subsistence. The Late/Final Jōmon and Epi-Jōmon/Okhotsk hypothesis were not supported citing the presence of more diversified and complex subsistence practices than was initially anticipated.
    • Regulating Hunting: Subsistence And Governmentality In The Central Kuskowkim Region, Alaska

      Vanek, Susan B.; Koester, David (2010)
      This paper explores the expansion of the state into formerly ungoverned aspects of life through an examination of one particular episode of intervention, that of moose hunting regulation in the Central Kuskokwim region of Alaska. As in most struggles over wild resources in the state, subsistence is a central organizing template. Local hunters residing in the villages of Aniak and Crooked Creek, interviewed for this work, identify themselves under the label of subsistence in opposition to others, often called "sport hunters". The felt presence of the state in this and other rural areas of Alaska has increased throughout the 20th century and the prevalence of the word subsistence in these disputes is tied to its status as a legal term, dictating how individuals must identify their practices and thus themselves, at the expense of other identifications. The persistence of subsistence indicates governmentality in discourse but not in meaning.
    • Regulation of ecdysteroid and vitellogenin levels during the molt and reproductive cycles of female dungeness crab, Cancer magister

      Thomton, Jamie David (2005-12)
      The reproductive cycle of Dungeness crabs is complicated by the requirement for molting prior to mating. The temporal requirements for molting and ovarian maturation may prohibit an annual reproductive cycle in a proportion of crabs. The goal of this study was to quantify temporal concentrations of circulating ecdysteroids and vitellogenins in female crabs during an annual cycle. Hemolymph in laboratory maintained crabs was sampled to assess physiological state (molting or reproduction). In laboratory crabs, ecdysteroid concentrations were low during intermolt (20.3 ng/ml), increased to maximal levels 15 days before ecdysis (1,886.5 ng/ml), and declined to low concentrations (<90 ng/ml) 5 days before ecdysis. Premolt duration was 150 days, with peak molting in November. Vitellogenin concentrations increased 6-fold during induced (via eyestalk ablation) ovarian maturation over a 90 ± 7.4 day vitellogenic period, and 4-fold for natural ovarian maturation over a 75 to 100 day period. The capability to predict ecdysis 150 days before molt and spawning 100 days before egg extrusion through hemolymph analysis is useful in molt and reproductive assessment of Dungeness crab populations. Additionally, in a preliminary study, reproductive failure and shell-disease were induced by physiological stress due to captive environmental conditions
    • Reindeer herding, weather and environmental change on the Seward Peninsula, Alaska

      Rattenbury, Kumi L. (2006-12)
      Intrinsic to the discussion about climate change is the effect of daily weather and other environmental conditions on natural resource-based livelihoods. Reindeer herders on the Seward Peninsula, Alaska have relied on specific conditions to conduct intensive herding in response to winter range expansion by the Western Arctic Caribou Herd (WAH). From 1992 to 2005, over 17,000 reindeer (affecting 13 of 15 herds) were lost due to mixing and emigration with the WAH. An interdisciplinary case study with one herder provided insights about the role of weather within the social-ecological system of herding. Inclement conditions disrupted herding plans at the same time that a smaller herd, diminished antler markets, and rising fuel costs have been disincentives to continue herding. Travel-limiting conditions, such as reduced visibility, delayed freeze-up, and early break-up, were implicated in herd loss to caribou or predators by several herders. However, these conditions have rarely been measured by climate change research, or they involve combinations of environmental factors that are difficult to quantify. If such events occur more frequently, as predicted by local residents and climate change models, herders will have to adapt to shorter and warmer winters, along with the continued presence of caribou in the region.
    • Reindeer Range Appraisal In Alaska

      Pegau, Robert Elwyn (1968)