Showing papers by "Oregon State University published in 1987"
TL;DR: Using the concept of "orbital tuning", a continuous, high-resolution deep-sea chronostratigraphy has been developed spanning the last 300,000 yr as mentioned in this paper.
3,256 citations
TL;DR: In this paper, a series of long-chain (C37, C38, C39) methyl and ethyl ketones, first identified in sediments from Walvis Ridge off West Africa and from the Black Sea, has been found in marine sediments throughout the world.
Abstract: A series of long-chain (C37, C38, C39), primarily di- and tri-unsaturated methyl and ethyl ketones, first identified in sediments from Walvis Ridge off West Africa and from the Black Sea1, has been found in marine sediments throughout the world2. The marine coccolithophorid Emiliania huxleyi and members of the class Prymnesiophyceae are now the recognized sources of these compounds3,4. Experiments with laboratory cultures of algae showed the degree of unsaturation in the ketone series biosynthesized depends on growth temperature2,5, a physiological response observed for classical membrane lipids6. Brassell and co-workers2,7 thus proposed that systematic fluctuations in the unsaturation of these alkenones noted down-core in sediments from the Kane Gap region of the north-east tropical Atlantic Ocean and correlated with glacial-interglacial cycles provide an organic geochemical measure of past sea-surface water temperatures. Using laboratory cultures of E. huxleyi, we have calibrated changes in the unsaturation pattern of the long-chain ketone series versus growth temperature. The calibration curve is linear and accurately predicts unsaturation patterns observed in natural particulate materials collected from oceanic waters of known temperature. We present evidence supporting the proposed palaeotemperature hypothesis2,7 and suggesting absolute 'sea-surface temperatures' for a given oceanic location can be estimated from an analysis of long-chain ketone compositions preserved in glacial and interglacial horizons of deep-sea sediment cores.
1,005 citations
TL;DR: Although the variable selection method improves the analysis of circular dichroism data truncated at 190 nm, data measured to 178 nm gives superior results, it is shown that improving the fit to the measured CD beyond the accuracy of the data can result in poorer analyses.
694 citations
TL;DR: In this paper, the authors reviewed the available information on El Nino occurrences, a regional manifestation of the large-scale (El Nino-Southern Oscillation (ENSO)) event, based on evidence obtained from the west coast region of northern South America and its adjacent Pacific Ocean waters.
Abstract: Applicable publications, involving five languages, have been reviewed to obtain information on El Ninos that occurred over the past four and a half centuries. Since this information refers strictly to El Nino occurrences, a regional manifestation of the large-scale (El Nino-Southern Oscillation (ENSO)) event, it is based primarily on evidence obtained from the west coast region of northern South America and its adjacent Pacific Ocean waters. Authored lists of events were not acceptable without referenced valid information sources. It was desirable to have cross-correlated reports from independent sources. Relative strengths of events are based on such considerations as wind and current effects on travel times of ancient sailing ships, degree of physical damage and destruction, amounts of rainfall and flooding, mass mortality of endemic marine organisms and guano birds, extent of invasion by tropical nekton, rises in sea temperatures and sea levels, affects on coastal fisheries and fish meal production, etc. Emphasis is placed on strong and very strong events. For example, the 1940–1941, 1957–1958, and 1972–1973 events fall into the strong category, whereas the 1891, 1925–1926 and 1982–1983 events are considered very strong. Over our period of study, 47 El Nino events were placed in the strong or very strong categories. Over the period 1800-present, we noted 32 El Nino events of moderate or near moderate intensity. Weak events are not included here. The approach used here caused us to revise many of our earlier evaluations concerning event occurrences and intensities. Our tropical Pacific thickness analyses and cumulative plots of Southern Oscillation index anomalies over the southeast Pacific trade wind zone showed additional evidence as to the unusual strength of the 1982–1983 event. Also, in our investigation we noted several periods of long-term (near decadal or longer) climatic change.
693 citations
TL;DR: In this paper, a general framework for forecast verification based on the joint distribution of forecasts and observations is described, and two factorizations of the joint distributions are investigated: 1) the calibration-refinement factorization, which involves the conditional distributions of observations given forecasts and the marginal distributions of forecasts, and 2) the likelihood-base factorization.
Abstract: A general framework for forecast verification based on the joint distribution of forecasts and observations is described. For further elaboration of the framework, two factorizations of the joint distribution are investigated: 1) the calibration-refinement factorization, which involves the conditional distributions of observations given forecasts and the marginal distribution of forecasts, and 2) the likelihood-base factorization, which involve the conditional distributions of forecasts given observations and the marginal distribution of observations. The names given to the factorizations reflect the fact that they relate to different attributes of the forecasts and/or observations. Several examples are used to illustrate the interpretation of these factorizations in the context of verification and to describe the relationship between the respective factorizations. Some insight into the potential utility of the framework is provided by demonstrating that basic elements and summary measures of the...
668 citations
TL;DR: The experimental approach is supplemented with theoretical calculations of nitrogen transformations in a shortgrass prairie, which incorporate a wide array of information on decomposer organisms, including their feeding preferences, nitrogen contents, life spans, assimilation efficiencies, productio:assimilation ratios, decomposabilities, and population sizes.
Abstract: Several experimental approaches have been taken to demonstrate the importance of soil fauna in nitrogen mineralization, but there have been difficulties interpreting the results We have supplemented the experimental approach with theoretical calculations of nitrogen transformations in a shortgrass prairie The calculations incorporate a wide array of information on decomposer organisms, including their feeding preferences, nitrogen contents, life spans, assimilation efficiencies, productio:assimilation ratios, decomposabilities, and population sizes The results are estimates of nitrogen transfer rates through the detrital food web, including rates of N mineralization by bacteria, fungi, root-feeding nematodes, collembolans, fungal-feeding mites, fungal-feeding nematodes, flagellates, bacterial-feeding nematodes, amoebae, omnivorous nematodes, predaceous nematodes, nematode-feeding mites, and predaceous mites Bacteria are estimated to mineralize the most N (45 g N m−2 year−1), followed by the fauna (29), and fungi (03) Bacterial-feeding amoebae and nematodes together account for over 83% of N mineralization by the fauna The detrital food web in a shortgrass prairie is similar to that of a desert grassland The shortgrass detrital web seems to be divided into bacteria- and fungus-based components, although these two branches are united at the level of predaceous nematodes and mites
664 citations
TL;DR: In this paper, the authors report analyses of O, Sr, Nd and Pb isotope ratios in 52 fresh glasses of mid-ocean ridge basalt (MORB).
629 citations
TL;DR: In this article, a two-layer model of soil hydrology and thermodynamics is combined with a one-dimensional model of the planetary boundary layer to study various interactions between evolution of the boundary layer and soil moisture transport.
Abstract: A two-layer model of soil hydrology and thermodynamics is combined with a one-dimensional model of the planetary boundary layer to study various interactions between evolution of the boundary layer and soil moisture transport. Boundary-layer moistening through surface evaporation reduces the potential and actual surface evaporation as well as the boundary-layer growth. With more advanced stages of soil drying, the restricted surface evaporation allows greater sensible heat flux which enhances boundary-layer growth and entrainment drying.
568 citations
TL;DR: Authigenic magnesian calcite, dolomite, and aragonite are precipitated in the uppermost terrigenous sediments of the Washington/Oregon accretionary prism by subduction-induced dewatering.
Abstract: Authigenic magnesian calcite, dolomite, and aragonite are precipitated in the uppermost terrigenous sediments of the Washington/Oregon accretionary prism by subduction-induced dewatering. These distinctive carbonates are methane-derived and occur at sites of concentrated pore-water expulsion. Unique biologic communities that subsist, at least indirectly, on methane (Suess et al., 1985) are also found at some of these sites. The methane, which is dominantly biogenic, is carried to the uppermost sediments of the prism by fluids and is oxidized by sulfate reducers before being incorporated into a carbonate cement. Carbonate precipitation occurs below the oxic layer, probably no deeper than several centimetres to a few metres below the seabed. Cementation may be induced by three factors: (1) increased carbonate alkalinity resulting from microbial sulfate reduction, (2) decreased σCO 2 solubility resulting from a pressure decrease when the pore water escapes the prism, and/or (3) the addition of Ca 2+ and Mg 2+ ions from sea water near the sediment/water interface. The convergent margin setting engenders precipitation of authigenic carbonates in several ways. Compressive stresses induce anomalously rapid compaction and dewatering rates, and they may cause overpressuring in migrating pore water, thereby delaying precipitation of carbonates until pressure is released near the sediment-water interface. Structural deformation of the accretionary prism creates pathways (such as fault zones), secondary fracture porosity, and dipping permeable layers (often exposed by mass movement) for efficient advection and expulsion of methane-enriched pore water. These characteristic conditions, which lead to the precipitation of methane-derived carbonates, may be found at other convergent margins.
550 citations
TL;DR: In this article, rare earth element concentrations in biogenic apatite of conodonts, fish debris and inarticulate brachiopods were determined in over 200 samples from Cambrian to modern sediments.
521 citations
TL;DR: The deduced 466-amino acid polypeptide exhibits extensive structural and sequence homology with other receptors coupled to guanine nucleotide binding proteins, and predicts a structure of seven membrane-spanning regions distinguished by the disposition of a large cytoplasmic domain.
Abstract: A partial amino acid sequence obtained for porcine atrial muscarinic acetylcholine receptor was used to isolate complementary DNA clones containing the complete receptor coding region. The deduced 466-amino acid polypeptide exhibits extensive structural and sequence homology with other receptors coupled to guanine nucleotide binding (G) proteins (for example, the beta-adrenergic receptor and rhodopsins); this similarity predicts a structure of seven membrane-spanning regions distinguished by the disposition of a large cytoplasmic domain. Stable transfection of the Chinese hamster ovary cell line with the atrial receptor complementary DNA leads to the binding of muscarinic antagonists in these cells with affinities characteristic of the M2 receptor subtype. The atrial muscarinic receptor is encoded by a unique gene consisting of a single coding exon and multiple, alternatively spliced 5' noncoding regions. The atrial receptor is distinct from the cerebral muscarinic receptor gene product, sharing only 38% overall amino acid homology and possessing a completely nonhomologous large cytoplasmic domain, suggesting a role for the latter region in differential effector coupling.
TL;DR: Experimental studies in the Pacific Northwest and the southeast U.S.A., and in Norway, are drawn upon to show that tree resistance to attack may be closely related to the amount of current and stored photosynthate that is available for defense.
TL;DR: Individual subtypes of a given receptor are capable of regulating multiple effector pathways, and the more efficiently coupled adenylyl cyclase response was significantly more sensitive.
Abstract: To investigate whether a particular receptor subtype can be coupled to multiple effector systems, recombinant M2 muscarinic receptors were expressed in cells lacking endogenous receptor. The muscarinic agonist carbachol both inhibited adenylyl cyclase and stimulated phosphoinositide hydrolysis. The stimulation of phosphoinositide hydrolysis was significantly less efficient and more dependent on receptor levels than the inhibition of adenylyl cyclase. Both responses were mediated by guanine nucleotide binding proteins, as evidenced by their inhibition by pertussis toxin; the more efficiently coupled adenylyl cyclase response was significantly more sensitive. Thus, individual subtypes of a given receptor are capable of regulating multiple effector pathways.
TL;DR: An acute physical stress may adversely affect fish by reducing, by about one-quarter, the energy available for other activities within the scope for activity of the fish.
Abstract: Juvenile steelhead Salmo gairdneri were subjected to three consecutive 2-min disturbances, separated by 0.5-h intervals, and then forced to swim at 0.5 body length/s for 1 h in a modified Blazka respirometer. Mean oxygen consumption (±SE) was 223 ± 19 mg˙kg−1˙h−1 in the stressed fish and 101 ± 9.7 in unstressed fish. There was no significant correlation between oxygen consumption and fish weight or water temperature within the ranges used (40–150 g and 8–11°C, respectively). Elevated plasma cortisol levels and oxygen consumption rates in stressed fish were positively correlated (r = 0.76). An acute physical stress may adversely affect fish by reducing, by about one-quarter, the energy available for other activities within the scope for activity of the fish.
TL;DR: The Jamestown Ophiolite Complex of the Barberton greenstone belt, South Africa, is investigated, and the intrusive nature of mafic-ultramafic units from the Komati and Kromberg formations into overlying pillow lavas and sediments is documented as mentioned in this paper.
TL;DR: Proliferation was reversibly inhibited by serum or platelet-free plasma, suggesting that mouse embryo cultures maintained by conventional procedures are under the influence of inhibitory factors.
Abstract: Mouse embryo cells cultured in vitro in serum-supplemented media undergo growth crisis, resulting in the loss of genomically normal cells prior to the appearance of established, aneuploid cell lines Mouse embryo cells established and maintained for multiple passages in the absence of serum did not exhibit growth crisis or gross chromosomal aberration Cells cultured under these conditions were dependent on epidermal growth factor for survival Proliferation was reversibly inhibited by serum or platelet-free plasma, suggesting that mouse embryo cultures maintained by conventional procedures are under the influence of inhibitory factors
01 Jan 1987
TL;DR: In this paper, the authors review the two major goals of butchery analysis within an historic context of several decades ago and present a brief description of how butchering patterns are infer.
Abstract: Publisher Summary
This chapter reviews the two major goals of butchery analysis within an historic context of several decades ago. It focuses on analytic techniques that have been and are being used to identify the hominid taphonomic agent in butchery analyses. It presents a brief description of how butchering patterns are infer. It also presents an explicitly taphonomic approach to the analysis of butchery in an attempt to integrate analytical techniques and goals into a coherent whole. The chapter also presents an example of butchery analysis that illustrates the explicitly taphonomic approach. It also explores the more recent attempts aimed specifically at identifying the taphonomic agents involved in faunal processing.
TL;DR: The SCSA will be of value for identification of low fertility sires and poor quality semen samples, and the relationship between sperm nuclear chromatin structure and fertility was evaluated in two groups of Holstein bulls.
Abstract: The relationship between sperm nuclear chromatin structure and fertility was evaluated in two groups of Holstein bulls: Group 1, 49 mature bulls, and Group 2, 18 young bulls. Fertility ratings had been estimated for Group 1 and nonreturn rates were known for Group 2. Semen samples were measured by the sperm chromatin structure assay (SCSA): sperm were treated to induce partial in situ DNA denaturation, stained with acridine orange, and evaluated by flow cytometry. Acridine orange intercalated into double-stranded DNA emits green fluorescence upon excitation with 488 nm light, and red fluorescence when associated with single-stranded DNA. An index of DNA denaturation per cell is provided by alpha-t [alpha t = red/(red + green) fluorescence]. The standard deviation (SD alpha t), coefficient of variation (CV alpha t) and proportion of cells outside the main population (COMP alpha t) of the alpha t distribution quantify the extent of denaturation for a sample. Intraclass correlations of the alpha t values were high (greater than or equal to 0.70), based on four collections obtained over several years from Group 1 bulls. Negative correlations were obtained between fertility ratings and both SD alpha t (-0.58, p less than 0.01) and COMP alpha t (-0.40, p less than 0.01) in Group 1, and between nonreturn rates and both SD alpha t (-0.65, p less than 0.01) and COMP alpha t (-0.53, p less than 0.05) in Group 2. These data suggest that the SCSA will be of value for identification of low fertility sires and poor quality semen samples.
TL;DR: In this paper, the authors examined the decision making processes of professional financial analysts who are screening prospective investments, including the identification of the decision-making processes, the decision rules, and the types of knowledge that are required to perform the task.
Abstract: This article examines the decision making processes of professional financial analysts who are screening prospective investments. The analysts were provided with a package of financial materials that reflected the magnitude and the types of information that they normally review. They were asked to verbalize “whatever came to mind” during their evaluation. The resulting transcripts, called protocols, formed the basis for the analysis. The protocol analysis produced a descriptive model of the financial screening process, including the identification of the decision making processes, the decision rules, and the types of knowledge that are required to perform the task. Particular attention is given to factors that differentiate among individual analysts.
TL;DR: In this article, the authors describe the evolution of the concept of the Recreation Opportunity Spectrum (ROS), a largely resource-based approach to providing recreational diversity, and explain the needs of the USDA Forest Service and USDI Bureau of Land Management for a recreation resource planning system and relate those needs to the development of the ROS system to guide recreation planning of large areas.
Abstract: This paper describes the evolution of the concept of the Recreation Opportunity Spectrum (ROS)—a largely resource‐based approach to providing recreational diversity. It explains the needs of the USDA Forest Service and USDI Bureau of Land Management for a recreation resource planning system and relates those needs to the development of the ROS system to guide recreation planning of large areas. The basic concepts and tenets of the ROS system are explained and needed research is outlined.
TL;DR: In this article, the parent and daughter element ratios and parent-and daughter element concentrations in 34 volcanic rocks from Samoa were reported and the most striking feature of the post-erosional data is a negative correlation between 207 Pb/ 204 Pb and 206 Pb+204 Pb.
TL;DR: In this article, the formation of fine-grained authigenic magnetites near the commonly observed brown-tan-green colour boundary, which marks the transition from Fe-oxidizing to Fe-reducing conditions, was investigated.
Abstract: The resolution and reliability of magnetostratigraphy and reconstructed time series of geomagnetic field behaviour depend critically on where remanence is acquired and fixed in the sediment column and whether the magnetization is altered chemically after deposition. If authigenic magnetic minerals are formed at depth or if the magnetic carriers are changed after deposition, then the nature and timing of magnetic events can be affected by depth offsets in remanence acquisition and mixing of detrital and authigenic signals. Using palaeo- and rock-magnetic and sediment geochemical analyses, we have studied how early diagenesis affects the magnetic properties of suboxic hemipelagic sediments. Here, we report evidence of the formation of fine-grained authigenic magnetites near the commonly observed brown–tan-green colour boundary, which marks the transition from Fe-oxidizing to Fe-reducing conditions. We propose that biogenic magnetite, produced by magnetotactic bacteria, forms as part of the microbially mediated sequence of reactions involved in the oxidation of organic matter. The magnetite is created as a metabolic by-product of the microorganisms' use of iron redox transitions as a source of energy. Active magnetite formation appears to be restricted to a zone between the levels of nitrate and iron reduction.
TL;DR: The mechanism of protection by vitamin E against chemical-induced toxicity to hepatocytes may be an alpha-tocopherol-dependent maintenance of cellular protein thiols in the near total absence of intracellular GSH.
TL;DR: In this paper, an approximately 260 kyr record of Melosira accumulation in an equatorial Atlantic sediment core was reported, and demonstrated significant influence of the Earth's precessional cycle on the climate of tropical Africa.
Abstract: High abundances of the freshwater diatom Melosira spp., reflecting eolian input from dry lake beds in tropical Africa, occur in deep-sea sediments of the equatorial Atlantic at discrete times during the late Quaternary1,2. We report here an approximately 260 kyr record of Melosira accumulation in an equatorial Atlantic sediment core, and demonstrate significant influence of the Earth's precessional cycle on the climate of tropical Africa.
TL;DR: In this article, the inadequacies of surface fluxes for use in numerical models of atmospheric flow are examined by assuming idealized spatial distributions of the Richardson number over a grid area.
Abstract: This study examines the inadequacies of formulations for surface fluxes for use in numerical models of atmospheric flow. The difficulty is that numerical models imply spatial averaging over each grid area. Existing formulations am based on the relationship between local fluxes and local gradients and appear to describe the relationship between the grid-averaged flux and the grid-averaged gradient poorly. For example, area-averaging the bulk aerodynamic relationship reveals additional spatial correlation terms and a complex relationship between the grid-averaged exchange coefficient and the stability based on “model” available” grid-averaged variables. This problem is studied by assuming idealized spatial distributions of the Richardson number over a grid area. Some perspective is provided by consulting observed spatial distributions of the layer Richardson number at the surface. Various contributions to the area-averaged surface flux are studied by employing a small-scale numerical model as a gri...
TL;DR: Samples from two localities near the crest of the Valu Fa ridge, an active back-arc basin spreading centre in the Lau Basin, consist of highly vesicular lava fragments of andesitic composition as mentioned in this paper.
TL;DR: Addition of supernatants from antigen stimulated pronephric cultures completely restored the ability ofpronephric lymphocytes to produce an antibody response, suggesting that this glucocorticoid-suppression may be mediated by inhibition of lymphokine production.
Abstract: The suppressive activity of cortisol on the invitro induction of coho salmon (Oncorhynchuskisutch) B cell activation was examined. Suppression was observed with splenic and pronephric (anterior kidney) derived lymphocytes. The kinetics of cortisol-induced suppression revealed distinct differences in the sensitivity of splenic and pronephric lymphocytes. Pronephric lymphocytes were only sensitive to cortisol early in the induction of the antibody response, whereas the splenic cells were sensitive to cortisol throughout the culture period. Addition of supernatants from antigen stimulated pronephric cultures completely restored the ability of pronephric lymphocytes to produce an antibody response, suggesting that this glucocorticoid-suppression may be mediated by inhibition of lymphokine production.
TL;DR: In this article, a Q-mode factor analysis of sediment textures and hydro-dynamic structures in 27 cores from the Chile Trench has been performed to define the lithofacies of the basin.
Abstract: The depositional bodies of the Chile Trench (trench fans, the axial channel, sheeted basins, ponded basins, and axial sediment lobes) control the spatial distribution of modem lithofacies in the basin. Sheeted basins (south of 41°S) are presumably fed by closely spaced submarine gullies that approximate a line of source of sediment supply along the base of the slope. Trench fans (41°S−33°S) are built at the mouths of major submarine canyon systems which act as point sources of sediment supply. The axial channel follows the northward gravitational gradient, draining the distributary networks of trench fans into the longitudinal transport system. Down-gradient (northern) fan lobes are severely dissected by erosional processes; evidently, periods of proximal deposition alternate with periods of massive sediment remobilization and progradation of the axial dispersal system into more distal environments. Channelized basins in the canyon-mouth areas yield to sheeted basins (depositional surface maintains an axial gradient) or ponded basins (depositional surface is strictly flat) in inter-canyon areas. Tectonic disruption of the oceanic basement can locally augment the axial gradient and stimulate flow channelization, or reverse the gradient and induce sediment ponding. A large, margin-parallel sediment lobe is built at the base of a high axial escarpment near 33°S, where the axial channel crosses a transverse discontinuity at the convergent plate boundary. Five lithofacies are defined by Q-mode factor analysis of sediment textures and hydro-dynamic structures in 27 cores from the Chile Trench. The Channel facies (thick, amalgamated sand, massive to laminated or cross-bedded) is deposited by high-energy processes within the coarse-grained bedload of turbidity currents; it forms in distributary and axial channels. The Levee facies (rhythmically bedded, internally structureless, graded sand and graded silt) is deposited from concentrated sediment suspensions that quickly lose momentum during channel spillover; it forms on channel flanks, although constructional levees are not always present. The Basin-1 facies (more complete Bouma sequences, both upper and lower flow regime structures) forms in ponded basins where flows are confined by a high-relief, seaward trench wall. The Basin-2 facies (graded and laminated silt, lower flow regime structures) forms in low-energy environments, such as interchannel areas, distal basins, trench walls, and elevated topographic features. The Contourite facies (silt and sand laminations winnowed from hemipelagic muds and distal turbidites) is best developed in sediment-starved basins where geostrophic currents are constricted and accelerated between the steep inner and outer trench walls. The trench wedge records a coarsening-upward sequence as the oceanic plate migrates toward and into the trench during plate convergence, and becomes more proximal to sediment sources along the base of the continental margin. Near canyon mouths, prograding trench fans drive the axial channel seaward into the trench wedge, and the coarsening-upward sequence is truncated by a time-transgressive erosional unconformity. Abandoned axial channel deposits are carried landward beneath prograding fans to record a fining-upward sequence above the basal unconformity. Channel migration and lobe aggradation may produce fining- and coarsening-upward sequences on depositional fan lobes, but sequences on the erosional lobes are fragmented by numerous truncation surfaces.