College Place, WA, United States
College Place, WA, United States

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Subramaniam K.,University of Florida | Gotesman M.,University of Florida | Smith C.E.,College Place | Steckler N.K.,University of Florida | And 3 more authors.
Diseases of Aquatic Organisms | Year: 2016

Megalocytiviruses, such as infectious spleen and kidney necrosis virus (ISKNV), induce lethal systemic diseases in both ornamental and food fish species. In this study, we investigated an epizootic affecting Nile tilapia Oreochromis niloticus cultured in the US Midwest. Diseased fish displayed lethargy, gill pallor, and distension of the coelomic cavity due to ascites. Histopathological examination revealed a severe systemic abundance of intravascular megalocytes that were especially prominent in the gills, kidney, spleen, liver, and intestinal submucosa. Transmission electron microscopic examination revealed abundant intracytoplasmic polygonal virions consistent with iridovirus infection. Comparison of the full-length major capsid protein nucleotide sequences from a recent outbreak with a remarkably similar case that occurred at the same facility many years earlier revealed that both epizootics were caused by ISKNV. A comparison of this case with previous reports suggests that ISKNV may represent a greater threat to tilapia aquaculture than previously realized. © Inter-Research 2016.

Dustin Becker C.,Maui Forest Bird Recovery Project | Mounce H.L.,Maui Forest Bird Recovery Project | Rassmussen T.A.,Maui Forest Bird Recovery Project | Rassmussen T.A.,College Place | And 2 more authors.
Endangered Species Research | Year: 2010

The Critically Endangered (IUCN) Maui parrotbill Pseudonestor xanthophrys, an endemic Hawaiian honeycreeper, is restricted to a single population of about 500 individuals. During 3 breeding seasons (2006 to 2008) we found and monitored 17 Maui parrotbill nests from 13 pairs. Eggs and incubating females were confirmed for 12 of the nests, but only 4 fledged successfully. Severe weather led to nest abandonment in 5 cases. Two nests were depredated, and 1 nest had an egg that failed to hatch. Three pairs renested after failures. We used logistic linear regression and ANOVA to evaluate 300 h of observations to assess the effects of parental investment behavior and weather on nest fate. Female time incubating, a significant factor explaining nest fate, did not differ by time of day, but averaged 12 min h-1 less for failed than for successful nests. Male provisioning rates to adult females and chick feeding rates by parents were also significantly related to nest success. Male vocalizations near the nest did not differ by nest fate. Establishment of a second population is a key step in the recovery of Maui parrotbills, and a small captive population has been established. Although limited, our data suggest that collection of Maui parrotbill eggs and/or nestlings up to 1 wk old from nests for captive rearing, especially in advance of severe winter storms, would have minimal effects on the population. © Inter-Research 2010.

Sealey W.M.,University of Idaho | Sealey W.M.,Bozeman Fish Technology Center | Barrows F.T.,U.S. Department of Agriculture | Smith C.E.,College Place | And 4 more authors.
Journal of the World Aquaculture Society | Year: 2013

Heat shock proteins (Hsps) can promote integrity of damaged intestinal epithelial tissues. The aim of this study was to determine the effects of a commercially available anti-phospholipase A2 antibody on growth, feed efficiency, Hsp expression, and intestinal health of rainbow trout fed diets containing high levels of soybean meal (SBM). Six practical-type diets (45% protein; 15% fat) were formulated to contain 0, 17.5, or 35% SBM with and without antibody. Each diet was fed to three replicate tanks of fish (20 fish/tank; initial weight 21 g) for 9 wk. RNA was isolated from liver and intestinal tissues (n =3/tank) to detect alterations in Hsp 27, Hsp 70, and Hsp 90 expression. Fish fed a diet containing 35% SBM had decreased growth and intestinal damage. Hsp 27 and Hsp 90 mRNA was elevated in fish fed 35% SBM. Fish fed 35% SBM with antibody had lower Hsp 90 mRNA expression than fish without antibody. These data indicate that feeding rainbow trout high levels of SBM alters the expression of some Hsps and anti-phospholipase A2 antibody supplementation does not normalize growth or prevent distal enteritis in fish fed 35% SBM.

Walker R.T.,Pennsylvania State University | Walker R.T.,NASA | Parizek B.R.,College Place | Alley R.B.,Pennsylvania State University | And 3 more authors.
Earth and Planetary Science Letters | Year: 2013

We develop a model of an ice shelf-ice stream system as a viscoelastic beam partially supported by an elastic foundation. When bedrock near the grounding line acts as a fulcrum, leverage from the ice shelf dropping at low tide can cause significant (~ 1 cm) uplift in the first few kilometers of grounded ice. This uplift and the corresponding depression at high tide lead to basal pressure variations of sufficient magnitude to influence subglacial hydrology. Tidal flexure may thus affect basal lubrication, sediment flow, and till strength, all of which are significant factors in ice-stream dynamics and grounding-line stability. Under certain circumstances, our results suggest the possibility of seawater being drawn into the subglacial water system. The presence of seawater beneath grounded ice would significantly change the radar reflectivity of the grounding zone and complicate the interpretation of grounded versus floating ice based on ice-penetrating radar observations. © 2012 Elsevier B.V.

Walker R.T.,Pennsylvania State University | Christianson K.,Pennsylvania State University | Christianson K.,St. Olaf College | Parizek B.R.,College Place | And 2 more authors.
Earth and Planetary Science Letters | Year: 2012

The motion of Bindschadler Ice Stream, West Antarctica, is dominated by sliding over a nearly plastic bed, according to analysis of kinematic GPS data using a new viscoelastic flowline model. Inversions of time-averaged velocity data with viscous ice-flow models can be consistent with multiple sliding laws, but propagation of velocity perturbations in a viscoelastic model can distinguish between sliding laws with different exponents. We develop such a model and apply it to a time series of velocity for the tidally modulated flow of Bindschadler Ice Stream (formerly Ice Stream D). Observed velocity perturbations are found to be consistent with a flow-law exponent m≥ 8, which indicates basal motion with a relatively weak till bed; lower exponents consistent with motion dominated by deformation within the ice over a hard or frozen bed are found to be unlikely. This result suggests that Bindschadler Ice Stream would respond rapidly and significantly to any future loss of buttressing from the Ross Ice Shelf. © 2011 Elsevier B.V..

Waryoba D.R.,College Place | Johnson J.A.,Contact Technologies Inc. | Stringer C.,College Place
Advances in Powder Metallurgy and Particulate Materials - 2014, Proceedings of the 2014 World Congress on Powder Metallurgy and Particulate Materials, PM 2014 | Year: 2014

Due to economic considerations, companies that produce electrical contacts are shifting from singlelayered to bi-layered electrical contacts. In this method, a thin layer of refractory based material (e.g. silver-graphite, silver-tungsten, silver-tungsten carbide) is bonded to a layer of pure copper (Cu) to create a bi-layered contact. Unfortunately, the traditional press, sinter, repress method has not been successful in producing bi-layered (clad) silver graphite (AgC)-Cu electrical contacts due to the presence of carbon (graphite) at the interface, as carbon is not diffusible into either silver or copper. This leaves a poor interface between the AgC section and the copper section decreasing the shear strength of the joint. This paper presents the results on the use of NiCr and Fe interlayers for diffusion bonding of bi-layered AgCCu electrical contacts.

Von Schilling C.,2011 622 Front St. | Straussfogel D.,College Place
56th Annual Meeting of the International Society for the Systems Sciences 2012, ISSS 2012: Service Systems, Natural Systems | Year: 2012

The thermodynamic laws governing open systems necessitate a cost to system complexity. The cost of system complexity represents an energetic debt in the system's surroundings called 'entropy debt'. This research begins with the premise that municipalities can be understood as complex, open systems and as dissipative structures. They garner energy (i.e. 'energy throughput') from their surroundings to build internal 'system complexity' such as social order, infrastructure, and communication networks. Regarding natural resources, the entropy debt of community complexity is the impact communities have on their natural environment - defined in this research as 'community entropy debt'. Environmental impact is problematic when it compromises the ecological integrity of the natural resources upon which communities rely. Given the necessary relationship between energy throughputs, in the form of natural resources such as food, fiber, and fuel, and community complexity, maintaining ecological integrity is paramount to community sustainability. Yet, despite community dependence on the natural environment, air, water, and terrestrial pollution and loss of sensitive ecosystems continue. This research asks, how can an open systems conceptual framework highlight the energeticentropic relationship between the system complexity of municipalities and the natural environment? How can such a conceptual framework effectively be operationalized and applied to municipalities? Finally, what can an analysis of the conceptual framework parameters reveal about systemic drivers of anthropogenic environmental degradation? First, this research views five British Columbia municipalities through the conceptual lens of the theory of dissipative structures. Second, this research abstracts from the conceptual framework an analogical model comprised of these inextricably linked parameters: 'energy throughput', 'system complexity', and 'entropy debt', to which the corresponding dimensions of municipalities and the natural environment are mapped. Third, this research identifies and applies surrogate measures for each parameter and then compares the data for each municipality. This paper introduces the research and highlights some of the preliminary data.

Parizek B.R.,College Place | Walker R.T.,Pennsylvania State University
Earth and Planetary Science Letters | Year: 2010

Ice-sheet grounding lines are sensitive to initial conditions and to small perturbations in boundary conditions, based on new model results coupling ocean and ice flow. To study ice-ocean dynamics near ice-stream grounding lines, we couple an ocean-plume model that simulates ice-shelf basal melting with a two-dimensional, isothermal model of ice-stream and ice-shelf flow. The notable results of the coupled model experiments are to reveal grounding-line migration sensitivities to i) specific aspects of modeling-derived and history-dependent initial conditions, ii) to the overall melt magnitude, and iii) to a positive feedback between focused melting and local slopes of basal ice that is eventually stabilized by buttressing for lengthening ice shelves. These interactions can lead to multiple steady states for ice flow over a bed that shallows in the along-flow direction and have an important bearing on the effects of bedrock bumps.When in the vicinity of bedrock highs, grounding lines tend to rapidly advance or retreat towards the basal asperity. A significant delay or cessation of (de)glaciation occurs once the grounding line reaches the leeward side of the bedrock crest. However, while bedrock bumps can offer stability in the grounding zone, minor changes in ocean conditions can easily offset their effect through basal melting feedbacks. © 2010 Elsevier B.V.

Waryoba D.R.,College Place | Stringer C.J.,Metals USA | Powell J.A.,CNRS French National High Magnetic Field Laboratory | Stiers E.,CNRS French National High Magnetic Field Laboratory
Advances in Powder Metallurgy and Particulate Materials - Proceedings of the 2015 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2015 | Year: 2015

Density is a predominant factor in the performance of powder metallurgy (PM) parts. High density materials are preferred because of their superior properties compared to low-dense materials. However, the tooling cost and geometry considerations limit the traditional compaction process from achieving higher densities. In this study, electromagnetic compaction was used as a secondary compaction process to provide additional densification for the much needed highdensity properties. The investigation was focused on the effects of electromagnetic compaction/compression on the density, microstructure, and mechanical properties of two variants of sintered steel PM compacts, FL-5305 and FY-4500. The results show that electromagnetic compression was more effective for densification of FL-5305 parts than for FY-4500. Also noted was the increase in the microhardness of electromagnetic compressed FL-5305 in comparison to as-sintered parts.

Haynal S.,College Place | Haynal H.,Walla Walla University
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2013

Recent research presents a technique to enumerate all valid assignments of 'twiddle factors' for power-of-two fast Fourier transform (FFT) flow graphs. Brute-force search employing state-of-the-art Boolean satisfiability (SAT) solvers can then be used to find FFT algorithms within this large solution space which have desirable characteristics. Surprisingly, this approach has discovered FFT algorithms requiring fewer operations than the split-radix algorithm even when all twiddle factors are nth roots of unity. This paper reviews and then extends this prior research to examine fast discrete convolution algorithms when implemented via FFT and inverse FFT (IFFT) algorithms. In particular, we find that the combination of FFT and IFFT algorithms in fast convolution permits greater freedom when selecting valid twiddle factor assignments. We exploit this freedom and use SAT solvers to find new fast convolution algorithms with the lowest operation counts known. © 2013 IEEE.

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