• Infection rates, parasitemia levels, and genetic diversity of hematozoa in New World waterfowl

      Smith, Matthew M.; Lindberg, Mark; McCracken, Kevin; Winker, Kevin; Pearce, John (2014-12)
      Blood parasites can limit the productivity of birds and increase the vulnerability of isolated and naïve populations to extinction. I examined 804 blood samples collected from 11 species of South American waterfowl to assess infection by Haemoproteus, Plasmodium and/or Leucocytozoon parasites. In addition, I strove to develop a new molecular tool to quickly and accurately determine relative parasitemia rates of Leucocytozoon parasites in avian blood. I used samples collected from waterfowl in interior Alaska (n = 105) to develop and optimize a real-time, quantitative PCR methodology using TaqMan fluorogenic probes. Molecular screening produced an apparent prevalence rate of 3.1% for hematozoa infections in South American waterfowl samples, and analysis of hematozoa mitochondrial DNA produced 12 distinct hematozoa haplotypes, four of which were identical to hematozoa lineages previously found infecting waterfowl in North America. Phylogenetic analyses of hematozoa DNA revealed close relationships between parasite lineages infecting waterfowl on both continents. Our qPCR assay showed high levels of sensitivity (91%) and specificity (100%) in detecting Leucocytozoon DNA from host blood when compared to results from a well-used nested-PCR protocol. Additionally, statistical results of a linear regression supported correlation between relative parasitemia estimates from our qPCR assay and greater numbers of parasites observed on blood smears (R2 = 0.67, P = 0.003).
    • Inflammatory stress in the cerebellum: implications for nutritional intervention in alcohol-mediated CNS damage

      Hogan, Mary Barile (2012-05)
      Presently there are no effective disease-modifying treatments to combat neurodegeneration among chronic alcoholics. Alcohol abuse imparts a sustained presence of oxidative stressors, including pro-inflammatory cytokine TNFα, in the brain. A persistent presence of TNFα leads to an accumulation of reactive oxygen species, which promotes oxidative damage, subsequent neurodegeneration, and ultimately permanent cognitive changes in afflicted individuals. Our laboratory has demonstrated the potency of ursolic acid, isolated from Alaskan blueberries, to abolish TNFα mediated neurotoxicity in human neuroblastoma cells. Our current study investigated the neuroinflammatory effects of ethanol and TNFα on dissociated neurons and glia cells cultured from embryonic chicks while quantitatively evaluating the preventive and therapeutic effectiveness of blueberry extracts. We compared both CNS and PNS neurons to examine correlations to clinically indicated neurodegeneration. Our results clearly revealed a particular sensitivity of cerebellar neurons to oxidative stress; however, supplementation with blueberry extracts rescued neuronal health by up-regulating antioxidant defenses, suppressing TNFα secretion, blunting lipid peroxidation, restoring cytoskeleton organization, modulating lipid rafts and altering the lipid environment of ion channels. Implementation of blueberries into the diet may offer an inexpensive and safe means to improve quality of life and reduce future health care costs associated with alcohol abuse and neurodegenerative disease.
    • The influence of climate and tectonics on topography in the Hayes Range and its foothills

      Vance, Gabrielle; Wallace, Wesley; Nadin, Elisabeth; Beget, James (2013-12)
      Complex feedback exists among climate, tectonics, and glacial erosion in the creation of topography: climate influences glaciation; tectonics and glacial erosion modify topography; topography influences climate. The objectives of this study are to determine elevation distribution in the Hayes Range area of the central Alaska Range and to identify evidence for structural or erosional controls. I have used geospatial information systems (GIS) software to map mean elevation, calculate geomorphic indices from a digital elevation model (DEM), and characterize climatic, tectonic, and topographic patterns. Deformation, elevation, and erosion all increase southward within the range. In the northern part of the range, Quaternary doubly plunging anticlines and thrust faults uplift and deform a relict landscape. Despite the dominance of fluvial erosion, these elliptical topographic highs are tectonically controlled. Similar larger elliptical topographic highs are present farther into the range to the south, but Quaternary structures are more difficult to identify because of greater glaciation and erosion. The study area is one of high mean elevation, summits, slope, and relief. Topography in the Hayes Range exceeds what would be expected if glacial erosion kept pace with rock uplift. A young antiform in the Hayes Range can account for the rapid rock uplift needed.
    • The influence of geomorphic and landscape characteristics on stream temperature and streamwater sensitivity to air temperature in the coastal temperate rainforest of Southeast Alaska

      Winfree, Michael; Stuefer, Svetlana; Hood, Eran; Arp, Christopher; Schindler, Daniel (2017-05)
      Climate warming is projected to increase the regional air temperature in southeast Alaska and alter precipitation patterns and storage, with potentially important implications for the region's aquatic resources. Streamwater temperature is controlled by energy inputs from the atmosphere and surrounding environment that are modified by a watershed's geomorphic and landcover characteristics. The climate-landcover relationships that influence stream temperature have not been comprehensively evaluated in southeast Alaskan watersheds. Thus, improving our understanding of current streamwater thermal regimes is critical to better assess how these regimes may be altered by climate change on a regional scale. In this study, seasonal streamwater thermal regimes in forty-seven watersheds across southeast Alaska were evaluated, and the influence of watershed geomorphic and landscape characteristics on stream temperature and streamwater sensitivity to air temperature was assessed. Stream temperatures were measured during the 2015 water year and analyzed for winter and summer seasons. Mean summer stream temperature ranged from 4.0°C to 17.2°C, while mean winter stream temperature were less variable across the region, ranging from 0.5°C to 3.5°C. Maximum weekly average temperatures (MWAT) ranged from 4.3°C to 21.5°C. Regression and time series analyses revealed that lower latitude, low gradient watersheds with higher lake coverage experienced warmer maximum and average summer stream temperatures and were more sensitive to air temperature fluctuations compared to higher latitude watersheds with high gradients during the summer. Winter mean stream temperature was warmer in higher gradient watersheds with greater forest and lake coverage. Moreover, higher latitude watersheds with steep gradients were less sensitive to changes in air temperature relative to low gradient / low latitude watersheds during the winter. Findings from this study demonstrate thermal regimes and air sensitivity are moderated by watershed geomorphology and landcover to create streamwater thermal heterogeneity across the coastal temperate rainforest of southeast Alaska. Results presented herein demonstrate that streamwater sensitivity to air temperature fluctuations are moderated by watershed geomorphology, and should be considered as a framework for predicting thermal regimes to assess relative watershed thermal response to climate change. This information, in turn, is important for quantifying the likely magnitude and spatial extent of climate-driven thermal impacts on Pacific salmon during their freshwater life history stages in southeast Alaska.
    • The influence of glaciers on coastal marine ecosystems in the Gulf of Alaska

      Arimitsu, Mayumi L.; Mueter, Franz; Beaudreau, Anne; Hood, Eran; Hobson, Keith; Piatt, John (2016-08)
      Glacier runoff (i.e., meltwater and rainwater discharged at the glacier terminus) provides about half of the freshwater discharge into coastal margins of the Gulf of Alaska, where contemporary glacier melting rates are among the highest in the world. Roughly 410 billion metric tons of glacier runoff enter the Gulf of Alaska each year. With freshwater discharge volumes of that magnitude, I hypothesized that glacier runoff has both direct and indirect effects on the receiving coastal marine ecosystems that support rich food webs, abundant and diverse marine communities, commercial fisheries and tourism industries. To examine the influence of glacier runoff on coastal marine ecosystems, I focused on three questions: 1) How does the marine food web respond to physical and biological gradients induced by glacier runoff? 2) What is the contribution of riverine organic matter (OM) and ancient carbon resources in glacier runoff to marine food webs from plankton to seabirds? and 3) How does the influence of glaciers on coastal marine ecosystems differ at small to large spatial and temporal scales? I measured physical, chemical and biological indices within four fjord systems along the eastern Gulf of Alaska coast. In chapter one I used geostatistics as well as parametric and non-parametric models to demonstrate a strong influence of glacier runoff on ocean conditions and coastal food webs across all the fjord systems. In chapter two I used isotopes (δ2H, δ13C, δ15N, and Δ14C) to trace riverine OM and ancient carbon resources into the marine food web. This work included the development of a novel multi-trophic level 3-isotope Bayesian mixing model to estimate the proportion of allochthonous resources in animal tissues. Mean estimates from 14 species groups spanning copepods to seabirds ranged from 12 – 45 % riverine OM source assimilation in coastal fjords, but ancient carbon use by marine food webs was low. In the third chapter I synthesized information on the scale-dependent influence of glaciers on lower-trophic level productivity, predator-prey interactions and ways that humans may be affected by anticipated changes in glacier coverage. This contemporary understanding of glacier influence on coastal ecosystems aligns with paleoenvironmental evidence suggesting that over geological time scales glaciers have and will continue to shape marine ecosystems in the Gulf of Alaska.
    • Influence of hydrological processes on the spatial and temporal variation in spawning habitat quality for two chum salmon stocks in interior Alaska

      Maclean, Scott H. (2003-05)
      I investigated the hydrological mechanisms that influence spatial and temporal variability in incubation habitat quality for summer- and fall-run chum salmon. The intragravel habitat was characterized by measuring water velocity, temperature, and dissolved oxygen (DO). Habitat quality was characterized by determining the survival of eggs in gravel filled baskets. Summer-run egg survival was greatest in a zone of upwelling produced by hydraulic gradients between the main Chena River and a slough. Water took approximately one month to make this trip and microbial activity likely reduced the concentration of DO considerably. As a consequence of these processes, there was considerable spatial and temporal variability in upwelling velocity, DO, and temperature. Most variability in egg-to-fry survival was explained by DO, and, to a lesser extent, by water velocity. Fall-run fish used an area of groundwater upwelling on the south side of the Tanana River. Here physical habitat characteristics were spatially and temporally uniform compared to the summer-run site, a consequence of the larger spatial scale of processes generating the upwelling. Egg-to-fry survival was low despite high DO and favorable temperature. This was probably the consequence of glacial silt invading egg baskets and reducing intragravel flow related to falling groundwater tables.
    • The influence of mechanical stratigraphy on the development of detachment folds and associated mesoscopic structures: an example from the Lisburne group carbonates, northeastern Brooks Range, Alaska

      Hayes, Michael Robert (2004-08)
      The mechanical properties of individual stratigraphic layers in a multi-layer sequence of sedimentary rock influence the deformational response before, during, and after fold development. To demonstrate this, the mechanical character of stratigraphic layers and mesoscopic deformational structures within individual stratigraphic layers were documented in two well-exposed outcrop-scale detachment folds in the Lisburne Group carbonates, northeastern Brooks Range, Alaska. Fold geometry and fold-related mesoscopic structures indicate that flexural slip and flexural flow are the operative fold mechanisms until a critical interlimb angle of 90° is reached, after which homogenous flattening occurs. Changes in bed thicknesses due to homogenous flattening alter the overall fold geometry. Lithostratigraphic unit boundaries do not always coincide with mechanical unit boundaries. Thin shale layers lower the bedding interface strength and commonly form flexural slip horizons that define mechanical unit boundaries. As fold shortening progresses, slip horizon spacing is interpreted to decrease, causing mechanical unit thickness to decrease. Newly forming mechanical boundaries alter the conditions of deformation, which change the overall fold dynamics. Surveyed fracture sets reveal the influence of lithology, mechanical unit thickness, anisotropy, and structural position on fracture distribution within individual mechanical units. Fracture densities vary from set to set and unit to unit due to structural and stratigraphic controls within these folds.
    • The influence of Paul Hindemith on trumpet repertoire

      Rabun, William; Gustafson, Karen; Krejci, Paul; Bicigo, James; Post, William (2016-03)
      The volume of quality trumpet repertoire available today is miniscule in comparison to the amount accessible for other instruments such as flute or violin. One significant reason for this disparity in repertoire is due to the vast developmental change that the trumpet has undergone since the turn of the 19th-Century. As a result, few well-known composers wrote for the instrument. This paper will discuss the impact of Paul Hindemith and his student Harald Genzmer on repertoire that features the trumpet as a solo instrument as well as the influence of jazz, and the 12-tone technique on Hindemith's compositional style. Additionally, the merit of the works of Hindemith's pupil will be discussed as well as the similarities found in the style of composition between student and teacher. Another issue that will be covered is to identify the difficulty of each work. To assess the difficulty o f the pieces I will analyze the range, technical ability required as well as the level of endurance needed to successfully perform each piece.
    • The influence of phenocrysts in silicic magma degassing

      deGraffenried, Rebecca; Larsen, Jessica; Freymueller, Jeffrey; Izbekov, Pavel (2017-08)
      Understanding the degassing process in magma is an important goal because of the first-order control it exerts on determining eruption style. Degassing in high viscosity magmas is of particular interest since these magmas tend to erupt explosively. However, the role of phenocrysts in the degassing process is still poorly constrained, though recent data indicate that the presence of phenocrysts should promote permeability development at lower porosities than in crystal-free magmas. This study specifically examined the effect of phenocrysts in a rhyolitic magma, but the results can also be applied to crystal-rich intermediate magmas that have rhyolitic matrix melts. Isothermal decompression experiments were conducted using powdered rhyolite (76 wt. % SiO2) and seeded with corundum (Al2O3) crystals to approximate magmas with 20 and 40 vol. % phenocrysts. Experiments were saturated at 900˚C and 110 MPa then continuously decompressed to final pressures between 75 and 15 MPa. Percolation threshold was determined by measuring permeability on a benchtop permeameter and measuring porosity from reflected light images. Additionally, vesicle structure was assessed by measuring pore throat radii from back-scattered electron images and plotting bubble size distributions. Finally, degassing state was checked by measuring dissolved water contents in the glass with Fourier Transform Infrared (FTIR) spectroscopy analyses. The addition of at least 20 vol. % phenocrysts resulted in a decrease in percolation threshold from 70-80 vol. % porosity in crystal-free rhyolites to 55 vol. % porosity. Bubble size distribution patterns indicate that coalescence was more widespread as final pressure decreased and crystal content increased. Minimum pore throat radii in the 40 vol. % phenocryst series were larger than in the 20 vol.% phenocryst and crystal-free series. The dissolved water measurements indicate that these experiments degassed in equilibrium even at the fast decompression rate of 0.25 MPa/s. Calculations of the magnitude of outgassing from the decreased percolation threshold and timescales of pressure dissipation indicate that the presence of phenocrysts plays a role in the effusive-explosive cyclicity of Vulcanian-style eruptions.
    • Influence of physical and biological oceanography on the structure of the seabird community in the northeastern Chukchi Sea

      Gall, Adrian E.; Blanchard, Amy L.; Weingartner, Thomas J.; Mathis, Jeremy T.; Hopcroft, Russell R.; Day, Robert H. (2015-12)
      The Chukchi Sea is losing seasonal ice cover as global temperatures rise, facilitating human access to the region for activities such as oil and gas exploration, shipping, and tourism. Processes and responses to environmental change by marine ecosystems are often challenging to quantify because they are hidden under water. Seabirds, however, offer visible evidence of the health and status of marine ecosystems. I studied the community structure, variability in abundance and distribution, and habitat associations of seabirds in the eastern Chukchi Sea. My results provide insights into the influence of climate change on seabirds and a benchmark against which to evaluate possible impacts of anthropogenic activity. Repeated sampling of systematic transects in the northeastern Chukchi Sea during the ice-free seasons of 2008-2012 showed that the community consisted of ~40 species and was dominated numerically by planktivorous seabirds, particularly Crested Auklets (Aethia cristatella) and Short-tailed Shearwaters (Puffinus tenuirostris). In contrast, benthic-feeding birds were rare. The abundance of seabirds in the offshore northeastern Chukchi Sea varied by up to two orders of magnitude among years and birds generally were more abundant in September than August. Despite these seasonal and interannual variations in abundance, the species composition was similar among years, with anomalies occurring only in years of persistent ice cover. I compared data from this recent period (2008-2012) with data from historical surveys (1975-1981) to evaluate decadal trends in seabird abundance and composition and related those changes to reductions in seasonal ice cover. The seabird community shifted from one consisting primarily of piscivorous seabirds to one consisting primarily of planktivorous seabirds. This shift suggests that zooplankton prey are more accessible now to avian predators as seasonal ice cover has declined. I explored the relationships between seabirds, hydrography, and zooplankton abundance with spatially explicit generalized additive models. The associations of seabirds with habitat characteristics varied with foraging method and preferred prey. Species that fed primarily by pursuit diving were more abundant in warm, weakly stratified water, whereas surface-feeding species were more abundant in cold, strongly stratified water. Planktivorous seabirds (auklets, shearwaters, and phalaropes) were more abundant within 20 km of thermal surface fronts and in contrast, omnivores (gulls and murres) were more abundant far from thermal fronts. For 5 of the 8 seabird species, information about prey biomass improved predictions of seabird abundance, although the relationships were not as clear as they were for the physical habitat characteristics indicative of processes that aggregate prey. Advective processes that transport oceanic species of zooplankton from the Bering Sea to the Chukchi Sea, together with the local influence of sea ice on physical and biological processes, strongly influence the distribution of seabirds, particularly the planktivorous species. Scientists and decision-makers can use the results of this multi-species and multi-disciplinary study as a benchmark to assess the ecological consequences of anthropogenic activity against the backdrop of climate change that is affecting the Chukchi Sea.
    • The influence of rookery terrain on population structure, territorial behavior, and breeding success of Steller sea lions in the Gulf of Alaska

      Smith, Louise N. (1988-05)
      The effect of rookery terrain on population structure, territorial behavior and breeding success of Steller sea lions was assessed at two rookeries, in the northern Gulf of Alaska. The sea lions using Sugar loaf and Marmot Islands differed in age structure, juveniles being absent from Sugar loaf but present on Marmot during the breeding season. Territory boundaries of breeding bulls on Sugarloaf were stable, and were unaffected by tides. Territory boundaries on Marmot were unstable, shifting with the tide. Territorial bulls occupied two types of territories on Sugarloaf Island (landlocked and water-access) and three types on Marmot (landlocked, tidal and semiaquatic). The behavior of territorial bulls on Marmot was influenced by tides and presence of juvenile animals. These factors were not important on Sugarloaf. The breeding success of territorial bulls was unaffected by location of territory on Sugarloaf. Territory location was important in the breeding success of Marmot Island bulls.
    • The Influence of terrestrial matter in marine food webs of the Beaufort Sea shelf and slope

      Bell, Lauren; Iken, Katrin; Okkonen, Steve; Wooller, Matthew; Bluhm, Bodil (2015-05)
      Terrestrial organic matter (OMterr) can function as a food source for Arctic marine consumers, though the relative contribution of OMterr to the structure and efficiency of marine food webs compared to marine production is unclear. Forecasted increases in OMterr inputs to the Arctic Beaufort Sea necessitate a better understanding of the proportional contribution of this organic matter source to the trophic structure of marine communities. This study investigated the relative ecological importance of OMterr across the Beaufort Sea shelf and slope by examining differences in community trophic structure concurrent with variation in terrestrial versus marine organic matter influence. Hydrogen stable isotope ratios (δD) of surface water, surface sediment particulate organic matter (sPOM), and selected benthic consumers were used as an exploratory assessment of freshwater and OMterr distribution in the Beaufort Sea. δD values of surface water confirmed the widespread influence of Canada's Mackenzie River plume across the Beaufort Sea; however, δD values of terrestrial and marine production were not sufficiently distinguishable to differentiate organic matter sources in consumers. Carbon stable isotope ratios (δ¹³C values) of pelagic particulate organic matter (pPOM) and marine consumers confirmed a significant decrease in OMterr presence and utilization by consumers with increasing distance from the Mackenzie River outflow. Food web length, based on the nitrogen stable isotope ratios (δ¹⁵N values) of marine consumers, was longer closer to the Mackenzie River outflow both in shelf and slope locations due to relatively higher δ¹⁵N values of pelagic and benthic primary consumers. The absence of macrofaunal consumers at the lowest trophic levels of OMterr-influenced food webs was interpreted to result from the prior metabolic turnover of OMterr by the microbial loop, which was not sampled in this study. The inferred presence of strong microbial processing of OMterr in the eastern regions of the Beaufort Sea resulted in a higher proportion of relative epifaunal biomass occupying higher trophic levels, suggesting that OMterr as a basal food source can provide substantial energetic support for higher marine trophic levels. These findings challenge the current conception of low terrestrial matter contributions to the Arctic marine food web, and compel a more specific understanding of energy transfer through the OMterr-associated microbial loop.
    • Influence Of The Kelvin -Helmholtz Instability On The Plasma Transport At The Magnetospheric Boundary

      Nykyri, Katariina (2002)
      The Kelvin-Helmholtz (KH) instability has long been suggested as a mechanism for viscous interaction at the magnetospheric boundary but it was not expected to produce significant mass transport. Satellite observations show that the density, temperature, particle pressure and total pressure of the plasma sheet are strongly correlated with those of the solar wind on a time scale of ~2 hours. I present a systematic 2-D study of reconnection in KH flow vortices using MHD and Hall-MHD approximations depending on magnetosheath and magnetospheric plasma and field properties. The presented results show that the Kelvin-Helmholtz instability can be a major plasma transport mechanism during times of strongly northward IMF providing a source of plasma into the low latitude boundary layer and plasma sheet on a time scale of ~2 hours. I have also analyzed Equator-S and Cluster satellite data at the dawnside magnetospheric flank and compared these results with MHD simulations in order to distinguish signatures caused by Kelvin-Helmholtz instability. In addition I have discussed typical ionospheric signatures caused by KH instability.
    • Influence of underfill filler settling on the thermomechanical reliability of the flip chip on board package

      Thammadi, Navin; Chen, Cheng-fu; Lin, Chuen-Sen; Lee, Jonah (2005-08)
      A Flip Chip on Board package (FCOB) is analyzed under thermal cycling loading to study the effect of underfill filler settling on the thermo-mechanical reliability of the package. The Mori-Tanaka method, a micromechanics based formulation, is utilized to model the property gradation caused by filler settling to obtain the effective material model for underfill. The modeling of the underfill material depends on the filler settling assumed. A total of five different underfill material models are used to assess their impact on the reliability. The equivalent underfill material properties calculated are subsequently used in finite element simulations to evaluate the FCOB assembly reliability. The reliability issues investigated in this work are solder joint fatigue and die cracking. This work aims to predict solder joint fatigue lifetime and also determine an acceptable pre-existing flaw size in the die backside to prevent die cracking. The results show that, when the underfill filler settling is gradual (instead of homogeneous), the corresponding solder joint has the minimum fatigue lifetime among the models assessed. However, the filler settling configuration has very little influence on the critical flaw size in the die and the board warpage.
    • Influence of weather on movements and migrations of caribou

      Eastland, Warren George (1991)
      Caribou (Rangifer tarandus granti) are typified by use of calving grounds and by making twice-annual migrations between summer and winter ranges. This study used satellite technology to examine the influence of weather on calving site selection, autumn and spring movements, and timing and directionality of migrations of the Porcupine Caribou Herd (PCH) that calves in northeast Alaska and northwestern Canada adjacent to the Beaufort Sea. The reigning hypothesis that females select areas that become free of snow early for calving sites was rejected because females selected areas of $>$75% snowcover ($P=0.02$) preferentially for calving. Benefits from use of mottled snow for calving were access to vegetation in its early phenological stages and protection for their calves from predators. Access to nutritious forage and predator avoidance appeared to be the main reasons for calving site selection. Multiple linear regression models were used to examine rate and direction of autumn and spring migrations using weather data from U.S. and Canadian sources. Weather was found to be both an ultimate and an approximate influence on the rate and direction of autumn migration ($P<0.05$). Explanatory power of the equations was low ($R\sb{a}\sp2<0.41$). Proximal causes of movement were best explained by caribou tracking of vegetation phenology. Pre-rut movements in September lacked concurrence between rate and direction whereas rate and direction were related in October. Models of spring migration of parturient females indicated a common timing among years, late April and early May, and movements were significantly affected by weather ($P<0.02$), in particular snow depths and conditions that would affect foraging and traveling conditions. This study suggests that: (1) females preferentially use areas of delayed snow melt for calving, and (2) weather influences both spring and autumn migration of caribou, although the effect of weather may be more indirect than direct.
    • Influences of abiotic factors on the return, ocean abundance, and maturity of sockeye salmon (Oncorhynchus nerka) in the northern North Pacific Ocean

      Yeh, Shinn-Pyng; Nishiyama, Tsuneo (1987)
      The fluctuations in return, ocean abundance, and maturity of sockeye salmon (O. nerka) were examined and related to wind stress curl, sea suface temperature (SST), sea level pressure, and cloudiness, in the area between 40$\sp\circ$N-60$\sp\circ$N and 160$\sp\circ$E-140$\sp\circ$W. Historical records, during two periods, 1971-76 and 1955-86, were the primary source of data. Spectral analysis of a 360-month period of mean wind stress curl during 1955-85 showed 3.1- and 5.3-year cycles. The 5.3-year cycle was correlated (r =.32 to.44, P $<$.10) with the return of Bristol Bay sockeye salmon mostly at 0- (the year of spawning migration) and 1-year lag (the first year of lake residence). The relative ocean abundance of sockeye salmon in the northwestern Northern Pacific during 1971-76 was lowest during the three periods: 1961-70, 1971-76, and 1977-85. Mature Kamchatka sockeye salmon were 24% more abundant than mature Bristol Bay sockeye salmon during 1971-76. A significant relationship was found between the May-June mean SST and abundance of sockeye salmon (r =.56 to.66, P $<$.01) during 1961-85. In the northern North Pacific, the SST was positively (r =.73 to.86, P $<$.001) related with the gonad weight of sockeye salmon. The results indicated a close relation between the return, ocean abundance, and maturity of sockeye salmon and most of the abiotic factors.
    • Infrared video tracking of UAVs: Guided landing in the absence of GPS signals

      Graves, Logan W.; Hatfield, Michael C.; Lawlor, Orion; Raskovic, Dejan (2019-05)
      Unmanned Aerial Vehicles (UAVs) use Global Positioning System (GPS) signals to determine their position for automated flight. The GPS signals require an unobstructed view of the sky in order to obtain position information. When inside without a clear view of the sky, such as in a building or mine, other methods are necessary to obtain the relative position of the UAV. For obstacle avoidance a LIDAR/SONAR system is sufficient to ensure automated flight, but for precision landing the LIDAR/SONAR system is insufficient for effectively identifying the location of the landing platform and providing flight control inputs to guide the UAV to the landing platform. This project was developed in order to solve this problem by creating a guidance system utilizing an infrared (IR) camera to track an IR LED and blue LEDs mounted on the UAV from a RaspberryPI 3 Model B+. The RaspberryPI, using OpenCV libraries, can effectively track the position of the LED lights mounted on the UAV, determine rotational and lateral corrections based on this tracking, and, using Dronekit-Python libraries, command the UAV to position itself and land on the platform of the Husky UGV (Unmanned Ground Vehicle).
    • Inhibition of Listeria in cold-smoked salmon using liquid smoke and isoeugenol

      Vitt, Susan M. (2000-05)
      Listeria monocytogenes is a foodborne pathogen, ubiquitous in nature and sometimes found in seafood. Cold-smoked salmon products have few barriers to inhibit pathogen growth. This study investigated the antilisterial effects of liquid smoke and the phenolic compound isoeugenol. Five commercial liquid smokes were tested 'in vitro' and the most inhibitory to Listeria monocytogenes ATCC 19115 and L. innocua ATCC 33090 was Charsol Supreme. Chum salmon samples (100-g each) were dipped for 15 seconds at varying concentrations of liquid smoke, processed, and analyzed for L. innocua. Liquid smoke concentrations of 60-100% reduced L. innocua by 3-logs in the final product. Dwell times of 15 seconds to 5 minutes using 60% liquid smoke gradually decreased listerial survival. Isoeugenol was antilisterial 'in vitro, ' but lacked synergism with liquid smoke in cold-smoked salmon. Charsol Supreme formed an antilisterial barrier in cold-smoked salmon, and may be a useful application to commercial products.