Showing papers by "Oregon State University published in 1982"

Bedload and Size Distribution in Paved Gravel-Bed Streams

Abstract: Field data are used to study the size distribution of bedload in paved gravel-bed streams Similarity analysis yields the results that all grain size ranges are of approximately equal transportability when the critical condition for breaking the pavement is exceeded This result is only approximately correct due to deviations from similarity However, it is adequate to justify development of a method for calculating total bedload, which requires only the subpavement median grain size rather than the size distribution A method for calculating bedload size distribution that accounts for deviation from similarity is also developed

Protochordate allorecognition is controlled by a MHC-like gene system.

Abstract: Colonial tunicates, unlike vertebrates, undergo transplantation in nature. Rejection or acceptance between colonies of Botryllus is controlled by a single gene locus with multiple alleles. The same genetic region apparently maintains this polymorphism by preventing fertilization between gametes sharing alleles. The Botryllus histocompatibility system may reflect the original adaptive function of ancestral MHC genes.

Hydrothermal petroleum in mineralized mounds at the seabed of Guaymas Basin

Abstract: Petroleum has been dredged from an active hydrothermal mound area in the southern rift of Guaymas Basin, Gulf of California. This organic matter is composed of gasoline-range aliphatic and aromatic hydrocarbons and predominantly residual polar asphaltic material. The aliphatic hydrocarbons of two bitumen samples have very different boiling range and composition. Both samples contain polynuclear aromatic hydrocarbons and olefins, which indicate formation at pyrolytic temperatures. The overall compositional data indicate an origin from biological detritus by thermal alteration and rapid quenching by hydrothermal removal, followed by condensation at the seabed.

Starvation-Survival of Heterotrophs in the Marine Environment

Abstract: Because microbes are the principal catalysts in the ocean, the preservation of the catalytic ability of bacteria is an important aspect of the cycles of matter. As long as the genome is preserved, it will be expressed when the environmental conditions become appropriate, and in many instances, this depends on the availability of suitable energy-yielding substrates.

Vibration Modes of Centrifugally Stiffened Beams

Abstract: The method of Frobenius is used to solve for the exact frequencies and mode shapes for rotating beams in which both the flexural rigidity and the mass distribution vary linearly. Results are tabulated for a variety of situations including uniform and tapered beams, with root offset and tip mass, and for both hinged root and fixed root boundary conditions. The results obtained for the case of the uniform cantilever beam are compared with other solutions, and the results of a conventional finite-element code.

A model of two-phase bedload transport in an oregon coast range stream

Abstract: A descriptive model for bed material routing in small sand and gravel bedded channels with sequences of pools and armoured riffles was developed. Aspects of the model are demonstrated at Flynn Creek, a 202-ha, third-order drainage in the Oregon Coast Range. Assuming that channel geometry, sediment transport competence, and the availability of sediments for transport are all non-uniform in the downstream direction, the model described bedload transport as occurring in two phases. Phase I involves the transport of fine, predominantly sand-sized bed materials over stable gravel-armoured riffles. Phase II occurs at higher flows that can entrain riffle armour and transport riffle sediments, in addition to Phase I sediments. Phase I bedload transport was sampled during three moderate flow events. A power function related Phase I bedload transport to water discharge. The relationship was consistent between storms and between two successive years. Phase II bedload transport, sampled during a 1.8-yr return period streamflow event in February, 1979, proved non-uniform in a downstream direction and unsteady over time at a given stream discharge. Transport rates closely correlated with the rapid scour and redeposition of the riffle at the bedload sampling cross-section; transport peaks corresponded to scour and transport decreased greatly during deposition. The transport of large (> 12.5 mm diam.) bed material increased up to 12-fold during riffle scour.

Momentum Balance of Gravity Flows

Abstract: A unified scale analysis of the momentum balance of downslope gravity flows is developed to organize previous theories for the case of negligible ambient flow and fixed temperature deficit scale. The values of several nondimensional parameters are evaluated from observations in the literature and used to assess the validity of certain sets of assumptions required for existing theoretical approaches. A new, simple solution is presented which includes both advective and frictional effects. This solution, as well as several other previous solutions, are found to be useful approximations for certain geophysical situations.

Premarital Abuse: A Social Psychological Perspective

Abstract: Little research has examined the incidence and dynamics of abuse between premarital partners at all levels of commitment. The present questionnaire study found the incidence of premarital abuse to be substantial and largely reciprocal in nature. Abuse typically began after some degree of commitment was established. Abuse was usually seen as caused by anger, although the effect of abuse on the relationship was not routinely seen as detrimental. It appeared that one possible explanation for abuse in these relationships was that those who stayed in abusive situations reported having fewer alternatives to the violent relationship than those who had terminated an abusive liaison. In general, the respondents had negative attitudes toward violence in relationships. However, those who had experienced abuse were more accepting of violence than those who had not experienced premarital abuse. The discussion focuses on several suggestions for further research to construct a clearer picture of premarital abuse.

The Nocturnal Surface Inversion and Influence of Clear-Air Radiative Cooling

Abstract: Nocturnal boundary-layer data from the Wangara and Voves experiments are analyzed. The lower part of the nocturnal inversion layer normally appears to be turbulent but strongly stratified. The upper thicker part of the inversion layer is characterized by weaker stratification which appears to be almost completely generated by clear-air radiative cooling. The radiative cooling is associated primarily with moisture, but is only modestly sensitive to the particular moisture distribution and thus varies little from night to night for the data analyzed here. The radiatively cooled layer thickens significantly as the night proceeds. On the other hand, the thickness of the turbulent layer normally varies slowly during the night, but differs significantly from night to night. For the inversion layer as a whole, turbulent heat flux divergence and clear-air radiative cooling make comparable contributions to the heat budget. The stratification normally decreases with height corresponding to negative curvatu...

Calcium carbonate hexahydrate from organic-rich sediments of the antarctic shelf: precursors of glendonites.

Abstract: Large euhedral crystals of calcium carbonate hexahydrate were recovered from a shelf basin of the Bransfield Strait, Antarctic Peninsula, at a water depth of 1950 meters and sub-zero bottom water temperatures. The chemistry, mineralogy, and stable isotope composition of this hydrated calcium carbonate phase, its environment of formation, and its mode of precipitation confirm the properties variously attributed to hypothetical precursors of the glendonites and thereby greatly expand their use in paleoceanographic interpretation.

Cropping Activities in Agricultural Sector Models: A Methodological Proposal

Abstract: Sector models may be constructed using two fundamentally different approaches. First, there are the large price-endogenous (reviewed in McCarl and Spreen) or cost-minimizing (reviewed in Heady and Srivastava) sector models, hereafter called SM. Second, there are modeling systems which contain a large number of representative farms (Sharples and Schaller, Walker and Dillon, or Thomson and Buckwell), hereafter called RFSM. The representative farm models, not emphasized in this paper, consist of many farm models which usually are iteratively solved into an equilibrium. Bell and Hazell present an application in which simultaneous equilibrium is determined. On the other hand, the SM sector models divide a country into regions, each containing aggregate activities and constraints. Typically, these models exhibit a rather poor replication of regional crop mix (e.g., Schaller or Burton). Flexibility constraints often are used to correct these deficiencies (Sahi and Craddock, Sharples and Schaller).

Fluxes of biogenic components from sediment trap deployment in circumpolar waters of the Drake Passage

Abstract: Circumpolar surface waters dominate the circulation of the Southern Ocean and sustain one of the ocean's largest standing stocks of biomass thereby producing a significant output of biogenic components, mainly diatoms, to the bottom sediments. Generally transit of biogenic matter from the sea surface to the sea floor affects nutrient regeneration fuels benthic life and transfers signals to the sediment record1–5. Reliable quantification of the relationship between biological production, fractionation of skeletal and tissue components and bottom sediment accumulation depends on direct vertical flux measurements from sediment trap deployments6–9, which have proved to be most scientifically productive10–13. We now present data on vertical mass fluxes from the Southern Ocean and evidence for strong biogeochemical fractionation between organic carbon-, nitrogen- and phosphorus-containing compounds, siliceous and calcareous skeletal remains, and refractory aluminosilicates.

A simple ice sheet model yields realistic 100 kyr glacial cycles

Abstract: Records of global ice volume for the past 700 kyr, based on oxygen isotopic data from deep-sea cores and reflecting mainly the changing Northern Hemispheric ice sheets, show a dominant cycle of roughly 100 kyr period. The records also show smaller-amplitude oscillations with spectral peaks at roughly 40 and 20 kyr periods, which are well correlated with the Milankovich insolation variations due to perturbations in the Earth's orbital parameters. However, no model has accurately simulated the 100 kyr glacial cycle. Recently Birchfield et al.1 and Oerlemans2 have obtained encouraging agreement with some features of the glacial cycle by using a simple ice sheet model with a realistic time lag in the response of the bedrock to the ice load. This study extends their basic model, first by including topography to represent high ground in the north. Improved results can then be obtained but only with unrealistic parameter values and for some aspects of the record. Further improvements areobtained by crudely parameterizing possible calving at the equatorward ice sheet tip during deglaciation by proglacial lakes and/or marine incursions from the Atlantic, as emphasized by Andrews3. The resulting ice volume curves agree fairly well with the observed records and their power spectra over the past 700 kyr.

Theory of Unidirectional Error Correcting/Detecting Codes

Abstract: In this paper we present some basic theory on unidirectional error correcting/detecting codes. We define symmetric, asymmetric, and unidirectional error classes and proceed to derive the necessary and sufficient conditions for a binary code to be unidirectional error correcting/detecting.

Confirmation of longevity in Sebastes diploproa (Pisces: Scorpaenidae) from 210Pb/226Ra measurements in otoliths

Abstract: Fish ages are often estimated by assuming an annual frequency of the band-like, growth-zones recorded in the largest of their otoliths, the sagittae. The total number of growth-zones are normally determined either by counting external growth-zones (whole otolith technique) or by examining otolith cross-sections (otolith section technique). The two techniques do not always yield the same age, however, particularly in older specimens of certain fishes. To resolve this problem, otoliths of the splitnose rockfish Sebastes diploproa were examined morphologically and were assayed for their natural radionuclide concentrations. Four age groups of otoliths were identified based on growth-zone counting; in the first three, whole otolith and otolith section age estimates agreed, while in the fourth, the otolith section age substantially exceeded the whole otolith age. Radiometric analysis demonstrated that all otoliths were deficient in 210Pb activity relative to 226Ra activity with the deficiency decreasing with increasing number of growth-zones. The magnitude of the 210Pb/226Ra radioactive disequilibrium in each otolith group, when compared to the number of growth-zones and the otolith weight histories derived with the two techniques, identifies the growth-zones revealed by otolith sections as annual features. Thus when otolith section age exceeds whole otolith age (usually occurring after 20 to 25 yr of age for this species), the otolith section technique is the correct method of age determination. Estimates of longevity in the genus Sebastes near 80 yr are therefore confirmed.

Accumulation of calcium oxalate in the mantle of ectomycorrhizal roots of pinus radiata and eucalyptus marginata

Abstract: SUMMARY Calcium oxalate crystals occur in the mantle of ectomycorrhizal roots of Firms radiata and Eucalyptus marginata. Dense concentrations of these crystals were observed in association with the fungal symbiont of both tree species. It is suggested that oxalate production may enhance nutrient uptake by ectomycorrhizal roots of forest species growing in nutrient impoverished soils. Concentrations of Ca, S, K and P were similar in mycorrhizal root masses of P. radiata and E. marginata.

Is the CH 4 , H 2 and CO venting from submarine hydrothermal systems produced by thermophilic bacteria?

Abstract: Submarine hydrothermal vents are a major source of methane to the oceans1,2 The methane, as well as H2 and CO, are generally believed to result from degassing of the mantle or from abiogenic water–rock reactions1, a conclusion supported by direct correlations between 3He and CH4, and generally between CH4, H2 and CO and dissolved silicate in hydrothermal waters2,3 An alternative source for these gases might be microbiological This would imply that active bacterial communities exist in deep-sea hot water environments, some of which have temperatures exceeding 100 °C; this inference is without precedent We have now found that the super-heated waters emanating from sulphide chimneys at 21 °N along the East Pacific Rise and samples from the sulphide chimneys themselves harbour complex communities of bacteria capable of growing with generation times of 37–65 min, producing CH4, CO, H2 and traces of N2O in media containing S2O2−3, Mn2+ and Fe2+ as energy sources, and oxidizing CH4, at 100 ± 2 °C at 1 atm These microbial communities consist of three to five morphologically distinct types and include both oxidative and anaerobic species These mixed cultures will not grow at temperatures below 70–75 °C Even though some of the communities originated from water of temperatures >300 °C, it is not known if they can grow and produce CH4, CO and H2 in super-heated waters kept liquid due to hydrostatic pressure The discovery of these obligately thermophilic, gas-producing and consuming bacterial communities associated with submarine volcanic environments has interesting and important implications for prokaryotic evolution, marine geochemistry, industrial microbiology and exobiology

Caradocian land plant microfossils from Libya

Abstract: The oldest paleontologically well-dated spore tetrads and cuti-clelike sheets of cells have been recovered from beds of Caradoc (mid-Ordovician) age from boreholes in the Murzuk (Murzuq) and Rhadames (Ghadāmis) Basins of western Libya. These microfossils together with late Llandovery–early Wenlock vascular plant megafossils (lycophytes and Psilophyton ) known from Libya lead us to conclude that land plants, including vascular plants, probably had a long pre-Silurian record, extending at least into the basal Caradocian. Additonal evidence suggests that this record does not extend as far back as the earlier Late Cambrian (Dresbachian).

Fish debris in sediments of the upwelling zone off central Peru: a late Quaternary record

Abstract: Scales of the anchoveta were abundantly represented among fish remains preserved in partly laminated marine sediments on the upper continental slope of Peru. Hake scales were less common. Sardine scales occurred only sporadically. Recent accumulation rates of scales indicate that prior to exploitation the anchoveta standing stock off Peru was about five times that of northern anchovy off California. During glacial time, however, clupeoids were less abundant off Peru and were more evenly distributed among sardines and anchoveta. Evidence from fish scales and phytoplankton assemblages suggests that the coastal waters off Peru did not respond to continental glacial and neoglacial advances simply by cooling. High accumulation rates of scales from warm-water fishes and tests of cool-water phytoplankton preceded and succeeded an interval containing low numbers of dominantly warm-water taxa. This interval coincided with the second neoglacial advance (2000 to 2700 y B.P.). Similar but less well-defined warm-water and cool-water assemblages coincided with the third neoglacial advance (200 to 400 y B.P.) and the last glacial retreat. Upwelling intensity probably fluctuated more widely during early and late phases of glacial and neoglacial cooling episodes, accounting for the mix of distinctly warm-water and cool-water assemblages and perhaps for an enhanced productivity. A weakened Intertropical Convergence Zone or strengthened coastal countercurrent may explain the warm-water marine faunas and floras and wet climates on the mainland of Peru inferred by others for neoglacial or glacial time.