Showing papers by "Oregon State University published in 1986"
TL;DR: In this article, the authors present a frame-work for a hierarchical classification system, entailed an organized view of spatial and temporal variation among and within stream systems, which is useful for research involving establishment of monitoring stations, determination of local impacts of land-use practices, generalization from site-specific data, and assessment of basinwide, cumulative impacts of human activities on streams and their biota.
Abstract: Classification of streams and stream habitats is useful for research involving establishment of monitoring stations, determination of local impacts of land-use practices, generalization from site-specific data, and assessment of basin-wide, cumulative impacts of human activities on streams and their biota. This article presents a frame-work for a hierarchical classification system, entailing an organized view of spatial and temporal variation among and within stream systems. Stream habitat systems, defined and classified on several spatiotemporal scales, are associated with watershed geomorphic features and events. Variables selected for classification define relative long-term capacities of systems, not simply short-term states. Streams and their watershed environments are classified within the context of a regional biogeoclimatic landscape classification. The framework is a perspective that should allow more systematic interpretation and description of watershed-stream relationships.
2,242 citations
TL;DR: In this paper, a simple formulation of the boundary layer is developed for use in large-scale models and other situations where simplicity is required, where some resolution is possible within the boundary layers, but where the resolution is insufficient for resolving the detailed boundary-layer structure and overlying capping inversion.
Abstract: A simple formulation of the boundary layer is developed for use in large-scale models and other situations where simplicity is required. The formulation is suited for use in models where some resolution is possible within the boundary layer, but where the resolution is insufficient for resolving the detailed boundary-layer structure and overlying capping inversion. Surface fluxes are represented in terms of similarity theory while turbulent diffusivities above the surface layer are formulated in terms of bulk similarity considerations and matching conditions at the top of the surface layer. The boundary-layer depth is expressed in terms of a bulk Richardson number which is modified to include the influence of thermals. Attention is devoted to the interrelationship between predicted boundary-layer growth, the turbulent diffusivity profile, ‘countergradient’ heat flux and truncation errors. The model predicts growth of the convectively mixed layer reasonably well and is well-behaved in cases of weak surface heat flux and transitions between stable and unstable cases. The evolution of the modelled boundary layer is studied for different ratios of surface evaporation to potential evaporation. Typical variations of surface evaporation result in a much greater variation in boundary-layer depth than that caused by the choice of the boundary-layer depth formulation.
1,195 citations
TL;DR: The Stewart Platform is one example of a parallel connection robot manipulator as discussed by the authors, and it has been used extensively in the past several years for a variety of tasks in the field of robotics.
Abstract: The Stewart Platform is one example of a parallel connection robot manipulator. This paper summarizes work that has been done at Oregon State University over the past several years on this topic. T...
820 citations
565 citations
TL;DR: This paper shows how this method is based on the construction of the generalized inverse from the singular value decomposition of a set of CD spectra corresponding to proteins whose secondary structures are known from X-ray crystallography without resorting to least-squares fitting and standard matrix inversion techniques.
531 citations
TL;DR: Evidence indicates an important role of glutathione, ascorbate, asCorbate peroxidase, dehydroascorbate reductase, andglutathione reduct enzyme as components of a peroxide-scavenging mechanism in soybean root nodules.
Abstract: The critical problem of oxygen toxicity for nitrogen-fixing organisms may be related to damage caused by oxygen radicals and peroxides An enzymatic mechanism is described for removal of peroxides in root nodules of soybean (Glycine max) The system utilizes ascorbate as an antioxidant and glutathione as a reductant to regenerate ascorbate The enzymes involved are ascorbate peroxidase (ascorbate:hydrogen-peroxide oxidoreductase, EC 11117), dehydroascorbate reductase (glutathione:dehydroascorbate oxidoreductase, EC 1851), and glutathione reductase (NADPH:oxidized-glutathione oxidoreductase, EC 1642) The reactions are essentially the same as those involving scavenging of H(2)O(2) in chloroplasts Glutathione peroxidase (glutathione:hydrogenperoxide oxidoreductase, EC 11119) was not detected During the course of early nodule development, ascorbate peroxidase and dehydroascorbate reductase activities and total glutathione contents of nodule extracts increased strikingly and were positively correlated with acetylene reduction rates and nodule hemoglobin contents The evidence indicates an important role of glutathione, ascorbate, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase as components of a peroxide-scavenging mechanism in soybean root nodules
469 citations
TL;DR: Hyperconcentrated flood-flow deposits are distinguished from normal, dilute streamflow deposits by lack of crossstratification in sand facies and by very poor sorting, poor imbrication, and numerous clasts with long axes oriented parallel to flow direction in gravel facies as discussed by the authors.
Abstract: Modern and ancient volcaniclastic sedimentary sequences contain depositional units whose features cannot be attributed to fully turbulent, dilute stream flow or viscous debris flow. The characteristics of these poorly sorted sediments suggest rapid deposition from high-concentration dispersions but not en masse . Sedimentation thus appears related to high-discharge flows intermediate in sediment/water ratio between stream flow and debris flow. The term “hyperconcentrated flood flow” is proposed for describing this intermediate condition. Hyperconcentrated flood-flow deposits are distinguished from debris-flow deposits by lack of matrix support or reverse grading and instead exhibit distribution normal grading and horizontal stratification. These deposits are distinguished from normal, dilute stream-flow deposits by lack of cross-stratification in sand facies and by very poor sorting, poor imbrication, and numerous clasts with long axes oriented parallel to flow direction in gravel facies. The horizontal bedding that dominates sandy hyperconcentrated flood-flow deposits consists of sediment too coarse grained and strata too thick to have been produced in the boundary layer of the upper-flow regime and should not be confused with the more familiar thin, graded laminae of fine- to medium-grained sand often associated with parting lineation. Hyperconcentrated flood-flow deposits are not unique to volcanic settings; they also occur in arid, alluvial-fan sequences. Debris-flow and hyperconcentrated flood-flow deposits, however, are much thicker and more extensive in volcanic regions than on alluvial fans because explosive volcanism leads to rapid mobilization of large volumes of sediment and water on a scale unparalleled in nonvolcanic settings. In volcanic regions, therefore, these deposits have greater preservation potential, show greater lateral variability, and are more voluminous. Transformation of channelized debris flow to hyperconcentrated flood flow by dilution with stream water, recently observed at Mount St. Helens, is recorded in ancient volcaniclastic sequences and may serve as the primary mechanism for generating hyperconcentrated flood flow.
469 citations
TL;DR: The animal communities and carbonates observed in the Oregon subduction zone occur in strata as old as 2.0 million years and provide criteria for identifying other localities where modern and ancient accreted deposits have vented methane, hydrocarbons, and other nutrient-bearing fluids.
Abstract: Transects of the submersible Alvin across rock outcrops in the Oregon subduction zone have furnished information on the structural and stratigraphic framework of this accretionary complex. Communities of clams and tube worms, and authigenic carbonate mineral precipitates, are associated with venting sites of cool fluids located on a fault-bend anticline at a water depth of 2036 meters. The distribution of animals and carbonates suggests up-dip migration of fluids from both shallow and deep sources along permeable strata or fault zones within these clastic deposits. Methane is enriched in the water column over one vent site, and carbonate minerals and animal tissues are highly enriched in carbon-12. The animals use methane as an energy and food source in symbiosis with microorganisms. Oxidized methane is also the carbon source for the authigenic carbonates that cement the sediments of the accretionary complex. The animal communities and carbonates observed in the Oregon subduction zone occur in strata as old as 2.0 million years and provide criteria for identifying other localities where modern and ancient accreted deposits have vented methane, hydrocarbons, and other nutrient-bearing fluids.
463 citations
TL;DR: This article provided a description of the van Hiele levels of reasoning in geometry according to responses to clinical interview tasks concerning triangles and quadrilaterals, including drawing shapes, identifying and defining shapes, sorting shapes, determining a mystery shape, establishing properties of parallelograms, and comparing components of a mathematical system.
Abstract: This study provides a description of the van Hiele levels of reasoning in geometry according to responses to clinical interview tasks concerning triangles and quadrilaterals. The subjects were 13 students from Grades 1 through 12 plus a university mathematics major. The tasks included drawing shapes, identifying and defining shapes, sorting shapes, determining a mystery shape, establishing properties of parallelograms, and comparing components of a mathematical system. The students' behavior on the tasks was consistent with the van Hieles' original general description of the levels, although the discreteness of levels, particularly of analysis and abstraction, was not confirmed. The use of formal deduction among students who were taking or had taken secondary school geometry was nearly absent, consistent with earlier observations by Usiskin (1982).
436 citations
405 citations
TL;DR: In this article, statistics of wave run-up maxima have been calculated for 149 35-minutes data runs from a natural beach using the zero-upcrossing method.
TL;DR: In this article, the skeleton structures of terrestrial cyclic terpenoids were analyzed in the solvent extractable material of fossil wood, ambers and brown coals and it was concluded from these structural distributions that aromatization is the main process for the transformation of terrestrial terpenoid during diagenesis.
TL;DR: In this paper, the depeletion of chalcophile and siderophile elements in the mantle was studied and it was suggested that the crust formation involves nonmagmatic and magmatic processes.
TL;DR: It is shown that healthy fish appeared more able than diseased fish to elevate plasma cortisol after each of the three successive disturbances, but plasma glucose concentrations following the repeated handlings were higher in the unhealthy fish.
Abstract: The corticosteroid and hyperglycemic stress responses to multiple acute disturbances were cumulative in juvenile chinook salmon Oncorhynchus tshawytscha. This was demonstrated by the stepwise pattern of increased plasma cortisol and glucose concentrations in fish subjected to a 30-s handling stress applied repeatedly at 3-h intervals over 6 h. The accumulation of physiological stress responses was substantiated by the resultant combined effects of these repeated disturbances on changes in concentrations of plasma lactate and of ionic sodium and potassium, and on the rate of decline of hepatic glycogen concentrations, all of which were greater than those that followed a single handling. Healthy fish appeared more able than diseased fish to elevate plasma cortisol after each of the three successive disturbances, but plasma glucose concentrations following the repeated handlings were higher in the unhealthy fish. As judged from plasma cortisol and glucose responses in fish subjected to a single 30-s...
TL;DR: The microbial equilibrium had been altered by formation of VA mycorrhizas, and specific groups of bacteria and actinomycetes in both the rhizosphere soil and rhizosplane were affected.
Abstract: The influence of infection by the vesicular-arbuscular (VA) mycorrhizal fungus Glomus fasciculatum on populations of general taxonomic and functional groups of naturally-occurring rhizosphere and rhizoplane bacteria and actinomycetes associated with roots of sweet corn (Zea mays var. rugosa) and subterranean clover (Trifolium subterraneum L.) was assayed on selective media. Total numbers of bacteria, but not actinomycetes, on the rhizoplane increased on plants with VA mycorrhizas (VAM) compared to plants without VAM. Bacteria and actinomycete populations were not affected quantitatively in the rhizosphere soil of VAM plants. However, VAM affected specific groups of bacteria and actinomycetes in both the rhizosphere soil and rhizosplane. Rhizosphere soil of mycorrhizal plants contained more facultative anaerobic bacteria, had fewer fluorescent pseudomonads, but had the same number of Gram-negative bacteria as non-mycorrhizal plants. Of the actinomycetes assayed, populations of both Streptomyces spp and chitinase-producing actinomycetes decreased in the rhizosphere, but not in the rhizoplane of mycorrhizal plants. Leachates of VAM and non-VAM rhizosphere soil were also compared for the presence or activity of bacteria that could influence sporulation by the root pathogen Phytophthora cinnamomi Rands. Fewer sporangia and zoospores were produced by P. cinnamomi in leachates of rhizosphere soil from VAM plants than from non-VAM plants, suggesting that sporangium-inducing microorganisms had declined or sporangium-inhibitors had increased. Since assays for specific functional groups of microorganisms revealed changes even when total numbers seemed the same, we conclude that the microbial equilibrium had been altered by formation of VA mycorrhizas.
TL;DR: In this article, molecular composition analysis has been applied to such extracts after suitable chemical separation into subfractions (i.e., hydrocarbons, ketones, fatty acids, fatty alcohols, and wax esters).
Abstract: Organic matter in aerosols is derived from two major sources and is admixed depending on the geographic area. These sources are biogenic detritus (e.g. plant wax, microbes, etc.) and anthropogenic emissions (e.g. oils, soot, etc.). Both biogenic detritus and some of the anthropogenic emissions contain organic materials (C14- C40 +) extractable by solvent, which have unique and distinguishable compound distribution patterns. Molecular composition analysis has been applied to such extracts after suitable chemical separation into subfractions (i.e. hydrocarbons, ketones, fatty acids, fatty alcohols, and wax esters). Microbial and vascular plant lipids are the dominant biogenic residues and petroleum hydrocarbons, with lesser amounts of the pyrogenic polynuclear aromatic hydrocarbons (PAH), are the major anthropogenic residues. These lipid fractions are quantified and characterized in terms of their contents of both homologous compound series and specific molecular markers. Samples from rural sites c...
TL;DR: In this paper, the authors define residuals as the signed square roots of the contributions to the Pearson goodness-of-fit statistic, which is defined as the contribution to the devia...
Abstract: Generalized linear models are regression-type models for data not normally distributed, appropriately fitted by maximum likelihood rather than least squares. Typical examples are models for binomial or Poisson data, with a linear regression model for a given, ordinarily nonlinear, function of the expected values of the observations. Use of such models has become very common in recent years, and there is a clear need to study the issue of appropriate residuals to be used for diagnostic purposes. Several definitions of residuals are possible for generalized linear models. The statistical package GLIM (Baker and Nelder 1978) routinely prints out residuals , where V(μ) is the function relating the variance to the mean of y and is the maximum likelihood estimate of the ith mean as fitted to the regression model. These residuals are the signed square roots of the contributions to the Pearson goodness-of-fit statistic. Another choice of residual is the signed square root of the contribution to the devia...
TL;DR: The LoNd array is defined by basalts from Tubuaii, St Helena, New England Seamounts, Comores, San Felix and Walvis Ridge.
TL;DR: Although inoculation with thePGPR or VAM fungi increased plant growth after 12 weeks, a significant increase in root dry weight, compared to uninoculated controls, was observed only when both the PGPR and VAM mushrooms were present.
Abstract: Plant growth and nodulation of subterranean clover ( Trifolium subterraneum L.) were studied in nonsterile soil inoculated with a plant growth-promoting rhizobacterium (PGPR) isolate of Pseudomonas putida and indigenous vesicular-arbuscular mycorrhizal (VAM) fungi. Although inoculation with the PGPR or VAM fungi increased plant growth after 12 weeks, a significant increase in root dry weight, compared to uninoculated controls, was observed only when both the PGPR and VAM fungi were present. Shoot dry weight of plants inoculated with PGPR and VAM was significantly greater than with the PGPR alone, VAM fungi alone or uninoculated controls. Nodulation was enhanced significantly by either the PGPR or VAM fungi alone (× 1.50-fold increase over controls at 12 weeks), but was significantly greater (× 2.03-fold increase over controls) when both the PGPR and VAM fungi were present. Inoculation with the PGPR increased colonization by VAM fungi from 7 to 23% of the root system infected at 6 weeks, but colonization levels by VAM fungi were similar (ca. 50%) at 12 weeks. Populations of the PGPR increased similarly in the rhizosphere of both mycorrhizal and nonmycorrhizal plants. Concentrations of Fe, Cu, Al, Zn, Co and Ni were considerably greater in the shoots of plants inoculated with the PGPR and VAM fungi than in plants inoculated with the PGPR or VAM fungi alone.
TL;DR: In this article, the effects of physical and chemical characteristics of the environment, mathematical modeling approaches of bacterial die-off and a summary of past investigations of bacterial death in storage systems, soil and fresh/sea water environments are discussed.
Abstract: To protect surface and groundwater resources from enteric bacterial pollution, management practices must be devised based on a sound knowledge of the fate of these organisms in the environment. Areas covered in this article include the effects of physical and chemical characteristics of the environment, mathematical modeling approaches of bacterial die-off and a summary of past investigations of bacterial die-off in storage systems, soil and fresh/sea water environments. The greatest need for future research efforts was shown to be in determination of the relationships of environmental and physical parameters to bacterial survival so that the literature data could be unified.
01 Oct 1986
TL;DR: The observed high rates of nitrate uptake and biogenic silica production imply that ice-edge phytoplankton blooms are a quantitatively important net source of organic and siliceous biogenic material within the Ross Sea.
Abstract: In the austral summer of 1983 we examined the spatial distributions of nutrients and phytoplankton biomass, nutrient assimilation rates and phytoplankton growth rates in an intense diatom bloom associated with a receding ice edge in the western Ross Sea. There was significant near-surface depletion of nitrate, phosphate and silicic acid within the bloom, but at almost all stations their concentrations remained higher than those generally considered limiting to phytoplankton growth. Ammonium concentrations within the bloom were frequently below detection limits (>0.1 μM in this study), and nearly always >0.25 μM. Rates of nitrate uptake were high enough to satisfy approximately 65% of the phytoplankton nitrogen demand estimated from 14C-primary productivity and particulate organic carbon: nitrogen ratios. Growth rates estimated for the overall phytoplankton assemblage based on 15N uptake, and the diatom assemblage based on 30Si uptake, were generally between 0.07 and 0.4 divisions per day. The mean rate of biogenic silica production within the bloom was 38 mmol Si m−2 day−1, which is an order of magnitude higher than previous estimates of silica production in the Southern Ocean, and comparable to rates observed in coastal upwelling systems at low latitudes. Accumulation of biogenic silica within the surface layer very nearly matched the depletion of dissolved silicic acid (i.e. the sum of these two quantities was very nearly conservative). The observed high rates of nitrate uptake and biogenic silica production imply that ice-edge phytoplankton blooms are a quantitatively important net source of organic and siliceous biogenic material within the Ross Sea.
TL;DR: The paper analyzes two classes of learning programs, called symbol level learning and nondeductive knowledge level learning, and speculates on the possibility of developing coherent theories of each.
Abstract: When Newell introduced the concept of the knowledge level as a useful level of description for computer systems, he focused on the representation of knowledge. This paper applies the knowledge level notion to the problem of knowledge acquisition. Two interesting issues arise. First, some existing machine learning programs appear to be completely static when viewed at the knowledge level. These programs improve their performance without changing their ‘knowledge.’ Second, the behavior of some other machine learning programs cannot be predicted or described at the knowledge level. These programs take unjustified inductive leaps. The first programs are called symbol level learning (SLL) programss the second, nondeductive knowledge level learning (NKLL) programs. The paper analyzes both of these classes of learning programs and speculates on the possibility of developing coherent theories of each. A theory of symbol level learning is sketched, and some reasons are presented for believing that a theory of NKLL will be difficult to obtain.
TL;DR: In this paper, the impacts resulting from visitors in backcountry settings have increasingly turned to normative explanations, and the authors build on earlier review articles by providing a conformance analysis of the impacts of visitors in a backcountry environment.
Abstract: Efforts to understand the impacts resulting from visitors in backcountry settings have increasingly turned to normative explanations This paper builds on earlier review articles by providing a con
TL;DR: Much additional research is required before the relationship(s) between environmental pollution and neoplasms in indigenous aquatic species can be understood, and the current state of knowledge in the general areas of fish and shellfish metabolism and the use of aquatic animal models in studies of chemical carcinogenesis is described.
TL;DR: Etude de l'adaptation de the physiologie digestive permettant a Selasphorus rufus et Calypte anna d'absorption des aliments sucres rapidement et efficacement.
Abstract: Etude de l'adaptation de la physiologie digestive permettant a Selasphorus rufus et Calypte anna d'absorption des aliments sucres rapidement et efficacement
TL;DR: Beneficial insects can be caused by bacterial and protozoan microbial pesticides and unique standard methods need to be developed for microbial assays for expressing more exactly the dosage administered to the host or natural enemy.
01 Oct 1986
TL;DR: It is concluded that the bloom was seeded by algae released from melting ice, and that an ice-edge bloom can have substantial impact on the biogeochemical cycles and foodweb dynamics of the Southern Ocean.
Abstract: During the austral summer in 1983, studies of primary productivity within a phytoplankton bloom associated with a receding ice edge in the western Ross Sea, Antarctica were conducted. Primary production was elevated within the ice-edge bloom, with integrated euphotic zone production averaging 40.1 mg C m−2h−1. The production was elevated in regions where the ice melt had created a strong vertical stability, and was decreased outside the zone of melt-water influence. Microautoradiographic analyses and species abundance data showed that a single species of diatom, Nitzschia curta, a species generally considered to be epontic, contributed up to 93% of the total productivity and 70% of the number of phytoplankton cells. Growth rates determined from autoradiography and carbon estimates based on cell volume as well as those determined from bulk production data agreed well and ranged from 0.1 to 0.5 divisions per day. No difference in growth rates between populations within and from outside the bloom was noted, an observation which we believe reflects the recent mixing of the phytoplankton as vertical stability weakened. We conclude that the bloom was seeded by algae released from melting ice, and that an ice-edge bloom can have substantial impact on the biogeochemical cycles and foodweb dynamics of the Southern Ocean.
TL;DR: In this article, measured variations of pivoting angles with grain size, shape (reliability and angularity) and imbrication are employed in analyses of grain threshold to examine how these factors influence selective grain entrainment and sorting.
Abstract: Measured variations of pivoting angles with grain size, shape (‘reliability’ and angularity) and imbrication are employed in analyses of grain threshold to examine how these factors influence selective grain entrainment and sorting. With a bed of uniform grain sizes, as employed experimentally to establish the standard threshold curves such as that of Shields, the threshold condition depends on grain shape and fabric. The analysis demonstrates quantitatively that there should be a series of nearly-parallel threshold curves depending on grain pivoting angles. For a given grain size, the order of increasing flow strength required for entrainment is spheres, smooth ellipsoids (depending on their ‘reliability’), angular grains, and imbricated ellipsoids (depending on their imbrication angles). The relative threshold values for these different grain shapes and fabric are predicted according to their respective pivoting angles, but remain to be directly tested by actual threshold measurements.
The pivoting angle of a grain also depends on the ratio of its size to those it rests upon. This dependence permits an evaluation of selective entrainment by size of grains from a bed of mixed sizes, the condition generally found in natural sediments. The pivoting model predicts systematic departures from the standard threshold curves for uniform grain sizes. Such departures have been found in recent studies of gravel threshold in rivers and offshore tidal currents. The pivoting model is compared with those threshold data with reasonable agreement. However, more controlled measurements are required for a satisfactory test of the model.
It is concluded that variations in pivoting angles for grain entrainment are significant to the processes of selective sorting by grain size and shape.