• Survivability of total coliforms in freezing and frozen soils

      Hrishikesh, Adhikari; Barnes, David L.; Schiewer, Silke; White, Dan (2005-08)
      The study showed that a significant fraction of coliform bacteria survive for more than six months in soil at different temperatures and moisture contents. Survivability of coliform bacteria at subzero temperatures decreased with an increase in moisture content and with an increase in temperature. Total coliform bacteria in soil samples placed outdoors during winter had lower survivability in comparison to samples placed at controlled temperatures below O⁰c. High survivability of total coliform bacteria at controlled, subzero temperatures was assumed to be related to the reduced metabolic activities of the bacteria.
    • Survival and activity patterns of snowshoe hares (Lepus americanus) in interior Alaska

      Feierabend, Dashiell S.; Kielland, Knut; Powell, Abby; Barboza, Perry (2013-08)
      Snowshoe hare (Lepus americanus) survival depends on the interaction of habitat characteristics with numerous biological and environmental variables. In boreal regions where considerable habitat heterogeneity exists, hares balance food availability with predation risk by moving among habitats seasonally, but it is largely unknown how often they move at shorter time scales. I investigated the seasonal effects of habitat, weather, and individual hare characteristics on survival and movement in two common but fundamentally different boreal habitats. Survival was highest in summer, for hares with higher body condition, and in black spruce rather than early successional forest. Hares moved among core use areas in different habitats twice per day on average, using more open areas at night when they were presumably feeding on preferred browse. Movement rates were lowest in mid-afternoon when hares appeared to be resting under dense cover. Behavior of individuals varied greatly with some hares repeatedly moving up to 1 km between defined patches in less than 5 hours and others remaining roughly within a 1 ha area. These findings illustrate the complexity of snowshoe hare ecology in an area where habitat variation promotes daily movement of hares among radically different habitats over a few hundred meters.
    • Survival and brood rearing ecology of emperor geese

      Schmutz, Joel A.; Sedinger, James; Rexstad, Eric; Ruess, Roger; Scwaegerle, Kent (2000-12)
      Emperor Geese (Chen canagica) breed on the Yukon-Kuskokwim Delta in an area inhabited by three other goose species. Whereas populations of other geese increased since the mid 1980s, Emperor Goose numbers remained low. Because survival and habitat selection by broods of Emeperor Geese had not been studied previously and numbers of predatory Glaucous Gulls (Larus hyperboreus) had recently increased, I studied brood rearing ecology of Emperor Geese during 1993-1996 to assess whether this seasonal period could be limiting population growth. Survival of goslings to 30 days varied among years from 0.32 to 0.70 and was primarily influenced by mortality during the first five days after hatch. Other goose species with similar rates of gosling survival are increasing rapidly. Survival of Emperor Goose goslings was lowest in 1994, when unusually heavy rainfall occurred during early brood rearing. Using a long-term data set from Izembek National Wildlife Refuge, sizes of families in fall (n=23 years) were related to rainfall during early brood rearing. Gosling survival was lower and gull disturbance of broods greater in 1993-1994 than in 1995-1996. Although goslings wer commonly consumed by Glaucous Gulls, gull diets during 1993 were similar to those observed in the 1970s. Across a broad scale, broods of Emperor Geese (n=56) strongly selected habitats dominated by Carex subspathaceae, Carex ramenskii, and unvegetated areas interspersed among these forage species, as determined from telemetry. These selected habitats comprised one-third of all available habitat. Habitat selection by the composite goose community (dominated by Cackling Canada Geese [Branta canadensis minima]) was assessed by feces collections and differed substantially from that of Emperor Geese. Broods of Emperor Geese spent more time feeding during 1993-1996 than during an earlier study in 1985-1986. During 1994-1996, feeding rates of gosling and adult females was related more to total goose density than to Emperor Goose density. Although Cackling Canada Geese exhibited strongest selection of other habitats, their greater overall abundance resulted in numerical equivalence to Emperor Geese in habitats preferred by Emperor Geese. Interspecific competition for food has impacted behavior in Emperor Geese, which may impact growth and survival of juvenile geese.
    • Survival and development of pink salmon (Oncorhynchus gorbuscha) embryos and fry as related to egg size and quantitative genetic variation

      Malecha, Patrick William (2002-08)
      The effect of egg weight on survival and development of pink salmon (Oncorhynchus gorbuscha) embryos, alevins, and fry was analyzed; in addition, embryo survival was investigated in relation to additive genetic variation. Embryonic survival to eyeing, development time to hatch, yolk weight, somatic tissue weight, yolk use rate, somatic tissue growth rate, and the survival of first-feeding fry was recorded relative to egg weight. The analyses demonstrated significant egg weight effects on development time to hatch, yolk weight, somatic tissue weight, yolk use rate, and somatic tissue growth rate on alevins. Weight and length of post-emergent fry (17 weeks post-ponding) were also significantly affected by initial egg weight. However, egg weight did not affect survival of eyed eggs or fry. Differential family-specific survival of eyed eggs indicated the presence of significant additive genetic variation.
    • Survival of duck nests, distribution of duck broods, and habitat conservation targeting in the Prairie Pothole Region

      Walker, Johann; Lindberg, Mark S.; Rotella, Jay J.; Ringelman, James K.; Hunter, Christine M. (2011-05)
      The Prairie Pothole Region (PPR) is an important breeding region for populations of upland-nesting ducks (Anas spp.). I studied survival of duck nests, distribution of duck broods, and conservation easement targeting in the PPR of North and South Dakota, USA. Nest survival of common duck species varied from 0.02 (ŜE = 0.01) to 0.23 (ŜE = 0.02) among study sites and years and was positively related to current pond density and primary productivity and negatively related to recent pond density and primary productivity. This result was consistent with the hypothesis that nest predators and thus nest survival were responding to changes in productivity induced by relatively short-term (1yr-2yr) precipitation cycles. Distribution of broods was positively related to wetland area and proportion of perennial grass cover on the study site. Estimated probability of wetland occupancy for a brood of a representative species, gadwall (Anas strepera), increased from 0.08 (90% Credible Interval: 0.07, 0.10) to 0.28 (0.24, 0.33) as wetland area increased from 0.19 ha to 2.12 ha. As proportion of perennial grass cover on a study site increased from 0.03 to 0.99, estimated probability of wetland occupancy by a gadwall brood increased from 0.12 (0.09, 0.16) to 0.20 (0.16, 0.25). These relationships identified wetland basins and landscapes with a higher probability of occupancy. The extensive repeat-visit brood survey was therefore a useful way to learn about the distribution of duck broods across a large geographic extent. I also investigated need and opportunity to refine current habitat protection strategies in the PPR. Area of habitat protected declined annually during 2000-2009 while cost of protection increased 248% from $210/ha to $730/ha and cropland rental rates increased 40%. Estimated area protected in 2009 was 210 km² (95% Confidence Interval: 133 km² to 287 km²), and 2,792 km² was protected during 2000-2009. Refocusing easement acquisition efforts on the 3,189 km² that was located in landscapes of highest priority based on pair density and was at relatively high risk of conversion, but was below the 25th percentile of cost provided a 24% reduction in per/hectare cost of protection and a 20% increase in area protected.
    • Surviving Alaska

      Cowley, Natalie; Alexie, Oscar; Thorne, Steve; Marlow, Patrick; Siekmann, Sabine (2015-12)
    • Suspended sediment transport and deposition in Alaskan coastal waters with special emphasis on remote sensing by the ERTS-1 satellite

      Burbank, David C. (1974-12)
      The large concentrations of suspended sediments in Alaskan estuarine and coastal waters form patterns which are clearly visible in imagery acquired by the Earth Resources Technology Satellite (ERTS). Density-slicing of the ERTS imagery is used to compile maps of relative suspended sediment concentrations. A comparison of these maps with conventional oceanographic data exhibits good correspondence and indicates that the synoptic, instantaneous and repetitive view provided by the satellite can be used to great advantage in interpreting the field data and extrapolating these data to areas where little conventional information is available. On the basis of this favorable comparison, ERTS imagery is used to delineate the major pathways of sediment transport in most of the Alaskan coastal zone, from Yakutat to Barrow. The resulting models are discussed in relation to the hydrological and meteorological regimes, sea circulation and bottom sediment distributions.
    • Sylph

      Moran, Christopher Cory; Burleson, Derick; Hill, Sean; Hirsch, Alexander; Kamerling, Len; Stanley, Sarah (2013-12)
      Sylph is a collection of poems that explores our relationship with mythology. It is interested in the similarity between identity and mythology, and the constant reinvention that both experience. It is interested in finding where myths intersects with individuals, societies, places, and other myths. The book attempts to create a panorama of landscapes both urban and rural, of figures ranging from alchemical spirits, animals from folklore, and gods of Greek, Egyptian, and many other descents. The poems frequently employ dramatic monologue in order to offer a voice to mythical figures. They focus primarily on content and imagery, favoring metaphor and simile. Sylph does not attempt to represent the entire body of mythology, but rather different figures that have intersected in a multicultural setting. Sylph regards both the reader and the mythical figures not as artifacts, but as beings that are in a process of continual growth and experience.
    • Symbolic stability of delay differential equations

      Averina, Victoria (2002-08)
      We offer a new symbolic computation of stability boundaries for linear systems of time-periodic delay differential equations with the period being equal to the delay. We construct an approximation of the 'infinite-dimensional Floquet transition matrix' U using the variation of parameters method, Picard iteration, and Chebyshev approximation techniques. A 'Mathematica' program approximately computes 'U'. We show the stability boundaries of well-known examples of delay differential equations in mathematics and mechanics.
    • Synchronization in biological systems

      Klaas, Jonathan P. (2004-12)
      Synchronization, the adjustment of rhythms via coupling, is an essentially nonlinear effect in coupled dynamical systems. Synchronization is observed in many systems, for example the moon's periods of rotation and revolution, in pendulums suspended from a common support, in swarms of fireflies that flash in unison, and in biological circadian rhythms. Circadian rhythms are periodic fluctuations in multiple physiological systems that have evolved as a consequence of the daily rotation of the earth. These rhythms have been observed in organisms ranging from cyanobacteria to man. In this thesis we will present a conceptually simple model of circadian rhythms to yield insight into the activity patterns of mice in light and food restriction experiments. The model consists of two coupled van der Pol oscillators that are driven by an external periodic influence representing food availability. The results of the model are compared to circadian data of mice collected by Dr. Abel Bult-Ito (Institute of Artic Biology).
    • Synergistic degradation of lignocellulose by fungi and bacteria in boreal forest soil

      Burgess, Robert A.; Leigh, Beth; Taylor, D. Lee; Reuss, Roger (2015-08)
      Boreal forests contain an estimated 28% of the world's soil carbon, and currently act as a significant global carbon sink. Plant-derived lignocellulose is a major component of soil carbon, and its decomposition is dependent on soil bacteria and fungi. In order to predict the fate of this soil carbon and its potential feedbacks to climate change, the identities, activity, and interactions of soil microbial decomposer communities must be better understood. This study used stable isotope probing (SIP) with ¹³C-labeled lignocellulose and two of its constituents, cellulose and vanillin, to identify microbes responsible for the processing of lignocellulose-derived carbon and examine the specific roles that they perform. Results indicate that multiple taxa are involved in lignocellulose processing, and that certain taxa target specific portions of the lignocellulose macromolecule; specifically, fungi dominate the degradation of lignocellulose and cellulose macromolecules, while bacteria scavenge aromatic lignocellulose monomers. Major fungal taxa involved in lignocellulose degradation include Ceratobasidium, Geomyces, and Sebacina, among others. Bacterial taxa processing lignocellulose and cellulose included Cellvibrio and Mesorhizobium in high abundance relative to other taxa, although Burkholderia were the primary vanillin consumers. These results elucidate some of the major players in lignocellulose decomposition and their specific roles in boreal forest soil. This information provides knowledge of small-scale microbial processes that dictate ecosystem-level carbon cycling, and can assist in predictions of the fate of boreal forest carbon stocks.
    • Synergistic effects among leading indicators of construction safety management

      Calhoun, Matthew E.; Schroeder, Herbert P.; Perkins, Robert A.; Bennett, F. Lawrence; Baker, Elisha R. IV (2015-12)
      Safety performance in the construction industry has improved significantly since the Occupational Safety and Health Act was enacted in 1970. Despite these improvements, annual accident statistics indicate the construction industry remains one of the most dangerous for workers. However, there are some construction companies that defy these statistics and have an exemplary safety record. Many of these companies have adopted a zero-accident vision and measure their safety performance using both leading and lagging indicators. Safety performance has traditionally been measured with only lagging indicators that have included recordable injury rates, experience modification rates, days-away-restricted-transferred, among many others. Unfortunately these indicators are recorded after an accident has occurred, resulting in management only being able to take a reactive approach. Conversely, a proactive approach uses leading indicators to alert management before an accident occurs. Previous research has found thirteen leading indicators that are connected to a strong safety performance for construction projects. However, several researchers and safety management experts recommend only monitoring and measuring two to three indicators on a project due to the resources required. Determining which leading indicators to monitor can be a difficult process for management new to this proactive approach. In an effort to help the construction industry, the first phase of data collection for my dissertation benchmarked the knowledge and use of leading indicators by interviewing twenty-five small contractors. The purpose of the interview was to identify leading indicators used by each small contractor and identify challenges to implementation when an indicator was not being used. The results were analyzed to find the total percentage of use for each indicator and their relationship to the contractor's total recordable injury rates. Two leading indicators were found to be linked with a safer total recordable injury rate and both indicators included having high percentages of workers employed for more than five years. The second and third phase of data collection for my dissertation focused on large owner and contractor companies who typically have had a better safety performance in comparison to small contractors. The Delphi method was used to assemble two separate expert panels to quantify the pairwise synergistic effects among thirteen leading indicators from the perspective of an owner and a contractor. The expert panel from the perspective of the owner found the leading indicators with the greatest synergistic impact included pre-task planning, project management team safety process involvement, housekeeping program, owner safety walkthroughs, worker observation process, owner participation in worker orientation sessions, and stop work authority. The other panel from the perspective of a contractor found the indicators with most synergistic impact were pre-task planning, near-miss reporting, worker observation process, an auditing program, and project management team safety process involvement. The results from this study can serve as an aid to all management that are beginning to take a more proactive approach towards measuring and monitoring safety performance.
    • A synergistic wearable health monitoring system using cellular network technology

      Pamidi, Nagarjuna; Raskovic, Dejan; Thorsen, Denise; McNeely, Jason B. (2017-05)
      This thesis presents a synergistic approach to healthcare applications by integrating a wearable health monitoring system into a smart home system. By exploiting synergy within each system and between these two systems, this thesis shows that the efficiency of the health care can be increased while providing the added advantage of utmost user-friendly environment. Initially, a wearable health monitoring prototype system was developed for vital sign data collection and processing. The developed system used biosensor integration to distinguish amongst multiple physical activities and to compare the variations in physiological conditions according to physical activity of the user. Afterward, system learning techniques were established for accomplishing the scalability of the health monitoring system. The resulting system is able to monitor different users without the need for explicitly changing the thresholds for the individual user. The health monitoring was further improved through integration with the smart home system to exploit synergy between various physiological sensors and to reduce false alarms generated by the system. A cellular communication interface was developed for transmitting the collected data to a remote caregiver and also to store the time-stamped data on the online web server. A web interface was developed to allow monitoring user's health and activity data, along with their surrounding environment.
    • A synopsis of the marine prosobranch gastropod and bivalve mollusks in Alaskan waters

      Foster, Nora Rakestraw (1979-12)
      This study presents information on the taxonomv and distribution of the marine prosobranch gastropod and bivalve mollusks from the waters surrounding Alaska. Three hundred fifty-two species of prosobranch gastropods and 202 species of bivalves are reported from these waters. Over 3,000 lots of specimens, representing 330 species and literature sources form the basis of this study. References, synonymy, geographic and bathymetric ranges are provided for each species. Characteristics used to identify the species of 66 genera are presented in tabular form. The greatest number of species is reported from the southern Bering Sea, the fewest from the Beaufort Sea. Most of the species have wide ranges in the eastern or western Pacific. New collecting records reported here extend the known ranges of 27 species. Eight species were previously unknown from Alaskan waters.
    • Synthesis and characterization of mechanical properties of a novel bioceramic composite material for biological applications

      Ladegard, Jillian; Zhang, Jing; Severin, Kenneth P.; Chen, Cheng-fu (2010-08)
      Bioceramics are used in a wide range of human skeletal repair and restoration applications as a synthetic bone substitute. 45S5 Bioglass, a bioactive ceramic, exhibits poor mechanical properties limiting the potential of the material and preventing its use in major load bearing applications. This investigation evaluated the synthesis and mechanical properties of a 45S5 Bioglass composite reinforced with different weight percentages of multi-wall carbon nanotubes. The material was analyzed using an X-Ray Diffractometer and a scanning electron microscope to determine the crystal structure, microstructural homogeneity, and surface texture of the composite material. The material was evaluated during the synthesis process to observe the evolution of the composite. Samples were sintered at 1000°C and 850°C to determine the effect of the sintering temperature on the mechanical properties of the composite. Once synthesized, the material was tested using the Vickers hardness indentation test to determine the mechanical properties of the ceramic, as defined by hardness and fracture toughness values. Hardness of the composite decreased with increasing nanotube concentration for all samples. A maximum fracture toughness value of 47.6 GPa·m¹/² corresponded to the addition of 1 weight percent multi-wall carbon nanotubes in the composite samples sintered at 1000°C. All of the composite samples sintered at 850°C reported lower fracture toughness values than the pure bioglass samples indicating that sintering temperature affects bonding between the composite components. These results prove that a Bioglass-multi-wall carbon nanotube composite has the potential for use as a synthetic material to restore function in load bearing bones
    • Synthesis and characterization of polymer-supported cyclodextrin nanoscaffolds for use in future environmental studies

      McKee, James Adrian; Green, Thomas; Trainor, Thomas; Simpson, William; Rasley, Brian (2016-08)
      The toxicity of transitional and post-transitional metals in natural water systems is well known. Coordination of these metals by selected ligands is a common means of environmental remediation. Macrocyclic coordination complexes impart thermodynamic and kinetic stability beyond their corresponding chelation analogues due to the pre-organized physical constraints of the coordinating ligands. Cyclodextrins are biologically produced and well-studied cyclic glucose macrocycles that possess chemically distinct hydroxyls. Amphiphilic cyclodextrins used as polymer-supported macrocyclic nanoscaffolds that are capable of scavenging trace metal pollutants could offer exciting new avenues of remediation research. Amphiphilic sodium hexakis (2,3-O-dibenzyl-6-O-sulfobutyl) cyclomaltohexaose (DBSBA) and sodium heptakis (2,3-O-dibenzyl-6-O-sulfobutyl) cyclomaltoheptaose (DBSBB) were synthesized in four steps. Aggregation colloids that possess an aromatic pseudophase in an aqueous system could provide new avenues of research for emulsion polymerization studies. The strong [pi]-[pi] interactions between the benzyls on the secondary rim and the polystyrene should anchor cyclodextrin nanoscaffolds to the nanoparticle surface. The aggregation of DBSBA and DBSBB was investigated using diffusion ordered NMR spectroscopy (DOSY), conductivity, and pyrene fluorescence techniques. These amphiphiles were found to possess near spherical symmetry at critical micelle concentrations of approximately 0.1 mM in all techniques used to study the phenomenon. These surfactants contain a high percentage of aromatic moieties in their structures, which affected the thermodynamics of aggregation by decreasing the CMC with increased temperature. Highly charged monodisperse polystyrene latex nanoparticles were produced using DBSBB as a surfactant in emulsion polymerization. The choice of surfactant was selected to examine its effect on polystyrene latex surface properties; amphiphilically modified cyclodextrins have not been used in emulsion polymerization recipes to date. Surface charge densities, up to 27 μS/cm², scaled with increasing amounts of added surfactant with a concomitant decrease in particle size. The addition of increasing amounts of DBSBB into emulsion polymerization recipes resulted in larger percentage coverage of latex particles. ¹H NMR studies found that the primary sulfobutyl substituents possessed fast molecular motions and therefore projected into solution and away from the latex surface. The strong physical adsorption of DBSBB and the presence of solvated primary rim substituents suggests that cyclodextrins can be used as future nanoscaffolds for the alteration of latex surface properties through non-covalent surface modification.
    • Synthesis and characterization of randomly 2,3-O-sulfoalkylated beta-cyclodextrins for use in chiral capillary electrophoresis

      Jaramillo, Michael (2013-05)
      Chiral separation of enantiomers is of vast significance in synthetic chemistry. Determining the enantiomeric purity of a product is necessary in the pharmaceutical industry. Recent studies in capillary electrokinetic chromatography (cEKC) have suggested that anionic cyclodextrins (CDs) are powerful chiral resolving agents. The purpose of this research was to synthesize a series of highly charged heptakis(randomly-2,3-O-sulfoalkyl)- ß- CDs, characterize the CDs, and apply the CDs to chiral separations of aryl alcohols. The synthesis focused on the sulfobutylation of heptakis(6-O-methyl)- ß- CD and heptakis(6-O-tert-butyldimethylsilyl)- ß-CD as well as the sulfopropylation of heptakis(6-O-tert-butyldimethylsilyl)- ß-CD. The degree of sulfoalkylation of the final products was determined by hydrophilic interaction chromatography (HILIC) with a low temperature evaporative light scattering detector (LT-ELSD). The synthesis of heptakis(6-O-methyl)- ß- CD was obtained by a lengthy protection/deprotection reaction scheme utilizing the acetylation of the secondary hydroxyl groups, with an overall yield of 43% in 5 steps. The sulfobutylation of heptakis(6-O-methyl)- ß-CD and heptakis(6-O- tert-butyldimethylsilyl)- ß-CD produced low degrees of substitution (DS <1.0). The sulfopropylation of heptakis(6-O-tert-butyldimethylsilyl)- ß-CD in tetrahydrofuran (THF) resulted in much higher degree of substitution, with DS of 3.3, 4.6, and 6.1, which increased with amount of added 18-crown-6 ether. Also, an increase in the DS (6.1 and 8.4) was observed when changing the solvent from THF to N, N-dimethylformamide. Chiral resolution studies of relevant aryl alcohols using potassium heptakis(randomly 2,3-O-sulfopropyl)- ß-CD (DS 8.4), potassium heptakis(2,3-di-O-methyl-6-O- sulfopropyl)- ß-CD (DS 4.5) and the single isomer potassium heptakis(2,3-di-O-methyl-6-O-sulfobutyl)- ß-CD were performed. Resolution of the enantiomers of the aryl alcohols is dependent on the distance of the chiral center from the aromatic ring and the substituent on the secondary rim of the cyclodextrin.
    • Synthesis and characterization of silver nanoparticles

      Lee, Mary Rose (2005-05)
      Silver nanoparticles may be prepared in aqueous solution by reducing silver nitrate with borohydride in the presence of sodium citrate and 4-4-(phenylphosphinidene) bis-(benzene sulfonic acid) (BSPP). Variation of the reaction conditions produces nanoparticles of different sizes, shapes, and chemical properties. For instance, the resistance to oxidation in the presence of cyanide can be increased by synthesizing nanoparticles using a high concentration of citrate. The differing chemical properties also show different results when using silver nanoparticles as a catalyst for the reduction of dichlorofluorescein. An induction time for the reduction reaction to begin was longer when nanoparticles were used that had been synthesized with a high concentration of BSPP. Finally, the surface effects of sulfur containing molecules on silver nanoparticles differ depending upon nanoparticle preparation. For example, silver nanoparticle solutions that were prepared with a high concentration of citrate showed a smaller shift in the Amax than those with a low concentration of citrate with the addition of L-cysteine.