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1551. [Article] Determining the bioavailability of soil-associated radium using in vitro methodology
Soil that is contaminated with radioactive elements poses an exposure hazard to those whom may take up temporary or permanent residence on such a site. Of particular interest is the internal exposure from ...Citation Citation
- Title:
- Determining the bioavailability of soil-associated radium using in vitro methodology
- Author:
- Tack, Krystina M.
Soil that is contaminated with radioactive elements poses an exposure hazard to those whom may take up temporary or permanent residence on such a site. Of particular interest is the internal exposure from ingestion of this radioactive soil. Although most ingestion of soil is inadvertent, usually being attached to foodstuffs that are not properly cleaned, it is possible that a person might consume a larger quantity. Childhood soil ingestion from simple hand-to-mouth activities is one explanation for this larger intake, as well as geophagia (eating dirt) or pica (craving and eating non-food items). The assumption that any person might consume a "mouthful" of dirt is a rare but possible occurrence that, when analyzed, will help with decisions about safe contamination levels of soil. Samples of soils contaminated with radium-226 were sent from an engineering and environmental firm to Oregon State University's Department of Nuclear Engineering and Radiation Health Physics for assessment. The analysis of the samples was aimed at the determination of bioavailability and bioaccessibility of the radioactive species found in the soils. Subsequent site remediation actions for the New Jersey-based project would be partially dictated by the results of Oregon State University's testing. Initially, the soils were tested for the presence of carbonates, for leachability of radioactivity in water and in acid, and for particle size distribution, i.e., soil type. Each of the eight samples was then subjected to a stomach/intestinal analogue to determine how much of the radioactivity would be transferred to solution upon human ingestion, (bioaccessibility). Mass balance and gamma spectrometry outputs for the soil samples before and after the digestion was one way the loss to solution was assessed. Another method to determine the loss of radioactivity to solution was to count aliquots of the digestive fluids in a high purity germanium detector, using a library of only radium isotopes and their progeny to locate peaks. The combination of results from mass balance and gamma spectrometry outputs allowed for OSU's researchers to determine the bioaccessibility of each soil's radioactive components. Using the determined bioaccessibility and previous animal models, the determination of bioavailability varied between the samples, from zero to 28% of the total initial radioactivity in the samples. A hot particle estimation of the dose from the non-bioavailable portion of the samples yielded a high dose to a small number of cells. Assuming ingestion of the most radioactive sample, (Sum-03a), the amount of damaged (killed) tissue in each section of the gastrointestinal tract was estimated to be less than 0.0407 cm³. This small volume of tissue is not likely to result in evident damage as the healthy human gastrointestinal tract regenerates all surface cells approximately every six days and most items are resident in the digestive system for less than 48 hours.
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1552. [Article] Hydrothermal alteration and oil show at the Summer Coon intrusive center, Saguache County, Colorado
The Summer Coon intrusive center is located seven miles north of Del Norte, Colorado, on the eastern edge of the San Juan Mountains. The intrusive center is the core of a dissected calcalkaline composite ...Citation Citation
- Title:
- Hydrothermal alteration and oil show at the Summer Coon intrusive center, Saguache County, Colorado
- Author:
- Loken, Trygve
The Summer Coon intrusive center is located seven miles north of Del Norte, Colorado, on the eastern edge of the San Juan Mountains. The intrusive center is the core of a dissected calcalkaline composite volcano of middle Oligocene age. The Summer Coon rocks belong to the Conejos Formation which is the oldest unit in the eastern part of the San Juan volcanic field. The intrusive core is a composite stock of three fine- to mediumgrained rock types. The oldest stock, a texturally inhomogeneous diorite, is cut by numerous radial dikes and is intruded inthe center by a granodiorite porphyry and a rhyolitic vent breccia. The granodiorite porphyry and the vent breccia are part of a 2500-foot diameter central conduit, while the diorite occupies a two mile diameter stock of uncertain origin. Hydrothermal alteration at the Summer Coon intrusive core grades concentrically inward from a propylitic zone to an intermediate argillic zone. The intermediate argillic zone has scattered pods of quartz-sericite and vuggy silica replacement of the host. The zone of intermediate argillic alteration centers on the 2500- foot diameter central conduit and radial dikes of silicic composition. Alteration at the study area was caused by hot spring activity beneath the water table during the fumarolic stage of the volcano. The chemical process of alteration was hydrogen metasomatism, which caused variable hydrolytic decomposition of plagioclase feldspar and mafic minerals leading to the depletion of calcium, magnesium, manganese, nickel, and cobalt in the rocks. Metallization is related to the abundance of pyrite in veinlets and fractures. Centrally located molybdenum and lead anomalies, and weak peripheral zinc anomalies characterize surface geochemistry at the study area. A supergene oxidized cap zone 35 feet thick has created a superimposed effect upon hypogene alteration, and the more mobile elements have been leached from it. The favorable aspects of the Summer Coon intrusive area as a porphyry copper-molybdenum exploration target include the existence of a composite stock with concentric zonation of hydrothermal alteration assemblages, and centrally located molybdenum, lead, and IP anomalies, low resistivity, and low magnetic value zones. Unfavorable aspects include the lack of structures, the lack of peripheral lead, zinc, silver, and gold mineralization, and the great depth at which hypothetical zones of intense hydrothermal alteration and mineralization may be located. Tarry brownish-black petroleum was present in pyrite-coated fractures in cores from three diamond-drill holes. The petroleum was dated and is interpreted to have been locally generated from Cretaceous source rocks and to have migrated into the intrusive core after the cessation of hydrothermal activity.
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1553. [Article] Hult Reservoir (Siuslaw Basin) Fish Species Composition Size and Relative Abundance_Final2018
Abstract -- Seven species of fish were encountered in Hult Reservoir in 2017: largemouth bass (Micropterus salmoides), cutthroat trout (Oncorhynchus clarkii), tainbow trout/winter steelhead (Oncorhynchus ...Citation Citation
- Title:
- Hult Reservoir (Siuslaw Basin) Fish Species Composition Size and Relative Abundance_Final2018
Abstract -- Seven species of fish were encountered in Hult Reservoir in 2017: largemouth bass (Micropterus salmoides), cutthroat trout (Oncorhynchus clarkii), tainbow trout/winter steelhead (Oncorhynchus mykiss), bluegill (Lepomis macrochirus), reticulate sculpin (Cottus perplexus), brown bullhead (Ameiurus nebulosus) and western brook lamprey (Lampetra richardsoni). The most abundant fish observed were largemouth bass and bluegill in the summer and fall, and cutthroat in the winter. Cutthroat trout were much more prevalent in the fall and winter sampling than in the summer. Presumably, most cutthroat trout moved up into the tributaries to seek thermal refuge during the summer months and returned to the reservoir once the temperatures were more conducive to growth and survival. However, some of them likely moved downstream, were preyed upon, or perished from the high summer temperatures and low dissolved oxygen conditions in the reservoir in summer. Under current conditions, high surface temperature (>20?), bass predation, and hypoxic dissolved oxygen levels below four meters of depth show that reservoir conditions are inhospitable for juvenile salmonids in the summer. Currently there are well established fisheries for both cutthroat trout (spring, fall, winter) and largemouth bass (summer) in the reservoir, and we talked to several anglers who target each of these species. Habitat segregation in the summer between the salmonids who move out of the reservoir and the warm-water fish that remain and spawn in the reservoir results in a diversified year-round angling opportunity. There were no coho salmon (juvenile or adult) observed in Hult Reservoir in 2017, but adult coho salmon were observed spawning just downstream of the dam. This observation verifies that a proportion of the adult coho attempting to ascend the ladder at Lake Creek Falls are successful and continue migration upstream to the vicinity of Hult Reservoir. It may be possible to keep the current fishery in Hult Reservoir as it stands and still increase coho production in the system by improving adult passage at Lake Creek Falls, and possibly at Hult Dam.
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1554. [Article] Abundance Monitoring of Juvenile Salmonids In Coastal Oregon and Lower Columbia Streams, 2008 Report Number: OPSW-ODFW-2009-1
Abstract -- As part of the Oregon Plan for Salmon and Watersheds, the Oregon Department of Fish and Wildlife (ODFW) initiated this project in 1998 to monitor the status and trend in abundance and distribution ...Citation Citation
- Title:
- Abundance Monitoring of Juvenile Salmonids In Coastal Oregon and Lower Columbia Streams, 2008 Report Number: OPSW-ODFW-2009-1
Abstract -- As part of the Oregon Plan for Salmon and Watersheds, the Oregon Department of Fish and Wildlife (ODFW) initiated this project in 1998 to monitor the status and trend in abundance and distribution of juvenile coho salmon (Oncorhynchus kisutch) in coastal Oregon streams. This report summarizes the data collected during the summer of 2008 and, for coho salmon, compares it to data previously collected. The project originally surveyed only 1st-3rd order (tributary) streams but was expanded in 2002 to include juvenile steelhead (Oncorhynchus mykiss) and 4th-6th order (mainstem) rearing areas and in 2006 to the Oregon portion of the Lower Columbia River coho evolutionarily significant unit (ESU) (Figure 1). The sampling frame is intended to encompass all non-tidal coho and steelhead rearing habitat. The original 100k stream layer frame was replaced by a 24k frame in 2007. A Generalized Random Tessellation Stratified design (GRTS) (Stevens 2002) was used to create a spatially balanced, random point distribution. Sites were stratified by Monitoring Area (MA) and stream order (Table 1). A detailed description of the sampling frames and survey designs are found in Jepsen and Rodgers (2004) and Jepsen and Leader (2007). Field crews snorkeled all pools meeting the size criteria (6 m2 in surface area and 40 cm in maximum depth) in one kilometer of stream encompassing the GRTS point. Snorkeling was conducted during the minimum flow period from July to September using a single pass of one to four snorkelers, depending on stream width. In each pool counts were made of juvenile coho, Chinook, steelhead 90 mm, and cutthroat 90 mm. Presence was noted for dace, shiners, and trout < 90 mm. Sites with poor water clarity or quality were electrofished using a single pass without block nets to determine presence for coho, steelhead and cutthroat in each pool. To assess repeatability and quality control supervisory staff resurveyed 10% of tributary sites in each MA. Data were summarized by MA and stream order for analyses. Average pool density and percent pool occupancy for each site was averaged by MA. The percent of sites with at least one fish and with >0.7 coho/m2 are reported for each MA. 0.7 coho/m2 is regarded as full seeding after Nickelson et al. (1992) who reported full seeding based on electrofishing as 1.0 coho/m2 and Rodgers et al. (1992) who found that snorkelers observed 70% of the coho counted by electrofishing. CDFs, variances, and confidence intervals were created using tools developed by the EMAP Design and Analysis Team (EPA 2009).
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1555. [Article] Leg 202 synthesis: Southeast Pacific paleoceangraphy
Ocean Drilling Program (ODP) Leg 202 has opened a new window into understanding late Paleogene and Neogene global environmental change by providing high-quality sediment sequences from a previously unsampled ...Citation Citation
- Title:
- Leg 202 synthesis: Southeast Pacific paleoceangraphy
- Author:
- Tiedemann, Ralf, Mix, Alan C.
Ocean Drilling Program (ODP) Leg 202 has opened a new window into understanding late Paleogene and Neogene global environmental change by providing high-quality sediment sequences from a previously unsampled region, the eastern South Pacific. Eleven sites (1232– 1242) that record variations on timescales ranging from decades to tens of millions of years were drilled and investigated on transects of both depth (489–4072 m) and latitude (41°S–8°N). Building on the shipboard results presented in the Leg 202 Initial Reports volume, postcruise research has significantly improved the stratigraphic framework and provided new insights into climate-related processes, which operate on different timescales and are relevant to hypotheses concerning the bipolar “see-saw” climate mechanism, orbitally driven changes in the continent-ocean-ice-atmosphere system and tectonic processes associated with the uplift of the Andes, closure of the Central American Seaway, and major expansions of polar ice sheets. Stable isotope records and refinements in bio- and magnetostratigraphy in combination with orbitally tuned cyclostratigraphy significantly improved the Pleistocene stratigraphy at Sites 1233 and 1234, the Miocene– Pliocene stratigraphy at Sites 1236, 1237, 1239, and 1241, and the Oligocene stratigraphy around the late Oligocene climate optimum at Site 1237. Site 1233 filled a crucial gap in the stratigraphic and paleoceanographic archive of the South Pacific sector of the Southern Ocean by providing an outstanding reproducible accelerator mass spectrometry (AMS) ¹⁴C-dated paleomagnetic record of centennial- and millennial- scale variability, representing regional variations in environmental/climatic conditions for the past 70,000 yr. With regard to the Cenozoic timetable, the continuous and complete sedimentary sequence of Site 1237, spanning the last ~31 m.y., has the potential of becoming a stratigraphic reference section for the South Pacific. Postcruise work demonstrated the excellence of this record for producing a stratigraphic framework that combines the biostratigraphy and terrific magnetostratigraphy with orbitally tuned stable isotope records. With respect to the bipolar see-saw hypotheses, Leg 202 studies on high-resolution records changed the view of the global distribution of millennial-scale climate change. These studies clearly demonstrate that millennial-scale climate and biogeochemical systems of the southeast Pacific and Chile closely align with those recorded in Antarctica and the southern oceans and that these climate patterns extend to the equatorial Pacific, either transmitted directly by the eastern boundary current or indirectly by “the oceanic tunnel” (subsurface transport via Antarctic Mode or Intermediate Water, Equatorial Undercurrent) injecting Southern Hemisphere extratropical water masses into the equatorial upwelling system. On orbital timescales, most spectacular was the finding that Earth’s final transition into an “icehouse” climate ~13.9 m.y. ago, the middle Miocene intensification of Antarctic glaciation, coincided with a striking transition from obliquity to eccentricity as the drivers of climate change. Thus, the late Pleistocene 100-k.y. climate cycles are not unique in Earth’s history, and although the examples from the Miocene and Pleistocene are both associated with climate cooling, they occur under significantly different global boundary conditions. This important contribution from Leg 202 issues a challenge to climatologists to understand multiple origins of 100-k.y. climate cycles that are now well documented in the geologic record. On timescales of millions of years, late Neogene upper ocean temperature reconstructions in combination with salinity assessments at selected sites from Leg 202 provide further insights into the reorganization of ocean-atmosphere couplings that are linked to the shoaling of the Central American Seaway (CAS), uplift of the Andes, and Pliocene amplification of polar ice sheet expansion. Regional shoaling of the thermocline in the low-latitude eastern Pacific from 5.3 to 4.0 Ma most likely resulted from shoaling of the CAS, as suggested by model experiments. Mixed-layer cooling and freshening in the tropical northeast Pacific warm pool as well as declining sea-surface temperature (SST) and increasing biological productivity off Chile parallel intensification of Northern Hemisphere glaciation from 3.6 to 2.4 Ma. The similarity of temporal changes in SST, upwelling, and dust flux between the Benguela and Chile upwelling systems suggests that uplift of the Andes was probably of secondary importance for generating the observed changes in the southeast Pacific within the last 6 m.y., as the Benguela upwelling system was not affected by mountain uplift. The expected atmosphere- oceanic response of the southeast Pacific to uplift of the Andes probably played a larger role during the late Miocene, prior to 6 Ma. A particular scientific challenge of future Leg 202 paleoclimate research is to better understand the transitions between these different timescales with respect to couplings between global, regional, and local processes.
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1556. [Article] The effects of tillage systems and seeding dates on grain yields of wheat (Triticum aestivum Vill., Host) on the Anatolian Plateau of Turkey
Wheat (Triticum aestivum) is the major food crop produced on the Anatolian Plateau of Turkey where due to limited rainfall the farmers follow the traditional system of fallow farming. They are presently ...Citation Citation
- Title:
- The effects of tillage systems and seeding dates on grain yields of wheat (Triticum aestivum Vill., Host) on the Anatolian Plateau of Turkey
- Author:
- Zinn, Thomas G.
Wheat (Triticum aestivum) is the major food crop produced on the Anatolian Plateau of Turkey where due to limited rainfall the farmers follow the traditional system of fallow farming. They are presently producing an average of 1.15 tons of grain per hectare during the crop year. This rate of production does not meet the needs of the country and during the last 15-20 years Turkey has frequently had to import wheat. The present fallow system permits extensive livestock grazing during the late fall and winter months in the noncrop year. Spring tillage practices are delayed to permit weed growth for additional foraging by livestock during the early and late spring period. This delayed spring tillage, using wooden or steel plows, leaves the soil loose and subject to rapid drying. Little plant residue is left on the surface to protect the soil and maintain water infiltration rates. The farmer also must cultivate several times before planting in order to prepare a satisfactory seedbed. Under these conditions Turkish farmers have learned that seed planted early in the fall in dry, warm soil may be germinated by light rain, subsequently dry out and then die. Thus, they have over time adopted the practice of delaying planting until late fall when temperatures are cooler and frequent rains more certain. Under these conditions the crop is largely dependent upon late spring and early summer rains for satisfactory grain production. Climate in dryland regions of Oregon and Washington are similar to those in the Anatolian Plateau. Previous research conducted on the Anatolian Plateau indicated that modified technology from Oregon and Washington could be adopted to Turkish conditions resulting in substantial increases in grain yield. The objective of this study was to compare three fallow-tillage systems for moisture conservation and early vs. late seeding dates on subsequent grain yield of wheat. The tillage treatments were (1) a fall chisel operation followed by a spring chisel tillage, (2) chiselling twice in the spring in perpendicular directions, and (3) moldboard plowing in the spring. All three systems received subsequent tillages with a sweep-harrow combination as required to maintain a weedfree fallow and uniform seedbed. The amount of moisture conserved was not affected by the three tillage systems employed and grain yield was not different due to tillage method. All of the systems conserved sufficient water to allow early seeding into residual moisture with a deep furrow drill. A 94 per cent stand emerged within 15 days. At a later sowing date wheat was seeded into dry soil using a double disc drill. Emergence was delayed due to late rains. After 56 days an 89 per cent stand had emerged. In this experiment a 36 per cent grain yield increase resulted from early seeding; 3.79 tons per hectare compared to 2.79 tons per hectare from the late seeded plots, a highly significant difference. The 3.79 tons per hectare is 2.64 tons per hectare more than the average yield from local farms, where a traditional fallow system is followed. The major components contributing to the yield increases from early seeding were (1) more plants and heads per unit area, (2) more kernels per head and to a lesser degree (3) kernel weight. This study suggests that if Turkish farmers adopt improved summer fallow systems, wheat yields can be increased significantly; thus, reducing or perhaps eliminating the need for importing wheat. However, the loss of grazing land under a clean fallow system for livestock will need to be evaluated in terms of the total economic and social conditions to determine if the increased wheat yields warrant the change in farming practices. It is anticipated that the loss of forage during the fallow period would be offset by the increase of stubble and cereal aftermath as a result of grain yield increase during the cropping sequence.
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1557. [Article] Submarine Magmatic-Hydrothermal Systems at the Monowai Volcanic Centre, Kermadec Arc
To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is an author's peer-reviewed final manuscript, as accepted by the publisher. ...Citation Citation
- Title:
- Submarine Magmatic-Hydrothermal Systems at the Monowai Volcanic Centre, Kermadec Arc
- Author:
- Schwarz-Schampera, Ulrich, Lupton, John, Baker, Edward T., Butterfield, David A., Hannington, Mark D., Leybourne, Matthew I., Chadwick, William W., Jr., Faure, Kevin, Embley, Robert W., Walker, Sharon L., Clark, Malcolm, Timm, Christian, Wright, Ian C., Massoth, Gary J., Resing, Joe, de Ronde, Cornel E. J., Graham, Ian J.
To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the Society of Economic Geologists and can be found at: http://econgeol.geoscienceworld.org/.
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Six Tertiary rock units are exposed in the Buster Creek-Nehalem Valley area. They are, from oldest to youngest: upper Eocene Tillamook Volcanics; upper Eocene Cowlitz Formation; upper Eocene Keasey Formation; ...
Citation Citation
- Title:
- Geology of the Buster Creek-Nehalem Valley area, Clatsop County, northwest Oregon
- Author:
- Olbinski, James Steven
Six Tertiary rock units are exposed in the Buster Creek-Nehalem Valley area. They are, from oldest to youngest: upper Eocene Tillamook Volcanics; upper Eocene Cowlitz Formation; upper Eocene Keasey Formation; upper Eocene Vesper Church formation (informal); upper Eocene to Oligocene Pittsburg Bluff Formation; and middle Miocene Depoe Bay Basalt. The Tillamook Volcanics is composed of basaltic andesite subaerial flows (SiO2 54.19% to 55.67%) and volcanic debris flows. The platy jointed subaerial flows are generally porphyritic with a pilotaxitic groundmass; a few aphyric flows with well defined flow banding are present. Highly vesicular flow tops typically show alteration of ilmenite to leucoxene producing a diagnostic bleached white appearance. Debris flows are comprised of very poorly sorted, angular, volcanic and minor sedimentary rock clasts in a mud matrix. Commonly this lithology is intruded by porphyritic and vesicular dikes. Major oxides of the Tillamook basaltic andesites suggest that these volcanic rocks may have erupted in an oceanic island "spreading center" environment. The Cowlitz Formation unconformably overlies the Tillamook Volcanics in the study area. This formation is divided into five informal members: a basal basaltic andesite conglomerate; a unit of interbedded micaceous arkese, volcanic lithic arenite and mudstone; a thick structureless mudstone; rhythmically laminated turbidite sandstone and siltstone; and a thick upper arkosic sandstone. The basal conglomerate represents a fluvial braided stream to high energy marine shoreline environment. The finer grained middle members indicate a deepening up sequence. The upper sandstone member is a micaceous, well-sorted, hummocky bedded, porous, very friable sandstone deposited in a high energy storm-dominated shelf to nearshore environment. The upper sandstone member of the Cowlitz Formation ("Clark and Wilson sand" of the Mist gas field) is the current target of active drilling in adjacent areas by several petroleum companies. This upper sandstone and lower arkosic sandstones represent favorable targets in contact with organic-rich, but immature, source rocks in potential fault bounded structural highs and erosional pinchouts in the northern part of the study area. The Narizian to Refugian Keasey Formation is represented by the Jewell member (informal), in the study area. The Jewell member, a well-bedded to laminated, tuffaceous, indurated mudstone, unconformably overlies the more extensively faulted Cowlitz Formation. Upper slope water depths of 200-600 m are indicated by foraminiferal and molluscan assemblages. A lithologically distinct and mappable turbidite unit crops out in the study area and is informally named in this thesis the Vesper Church formation. The Vesper Church formation represents west- to northwest-trending turbidite-filled "sea gullies" deposited at bathyal depths (1,000-1,500 m) on the lower slope. Thin-bedded channelized turbidites with Bouma c, d and e sequences and local thick amalgamated sandstones characterize this unit. The upper Eocene (Refugian) Pittsburg Bluff Formation conformably overlies the Vesper Church formation. Molluscan assemblages from the basal part of this formation indicate water depths of 20-200 m; thus, a significant shallowing episode between the Vesper Church and Pittsburg Bluff formations is indicated. Thick, bioturbated, glauconitic to fine-grained tuffaceous sandstone and sandy mudstone suggest an inner to middle (possibly outer) continental shelf depositional environment for the Pittsburg Bluff strata. Following a period of high-angle northeast trending faulting, two middle Miocene Depoe Bay Basalt dikes intruded the sedimentary formations exposed in the area. The reversely polarized Northrup Creek dike can be traced over 8.5 km and has a paleomagnetic declination of 170° and a steep inclination of -74°, possibly a result of secular variation of the geomagnetic pole during cooling of the dike through its Cuire temperature (Nelson, 1983). These aphanitic to sparsely micro-porhyritic tholeiitic basalts are chemically identical to the Grande Ronde Basalt of the Columbia Plateau. A recent hypothesis by Beeson et al. (1979) suggests that all Miocene coastal basalts represent the distal ends of subaerial Columbia River basalts which reached the Miocene shoreline and intruded or "invaded" soft marine sediments. The reversed stratigraphic order of high and low MgO Depoe Bay (Grande Ronde) basaltic sills intruding Keasey and Cowlitz strata, as much as 1600 m below the surface in the petroleum exploration well Quintan_a Watzek 30-1 Watzek 30-1 in this study area, illustrates a complicating factor in the emplacement mechanism if these are "invasive" intrusions. In late middle Miocene the northern Oregon Coast Range anticline was formed, possibly in response to a period of underthrusting (Snavely et al., 1980b). Contemporaneously, a second set of left-lateral and right-lateral conjugate faults (N55°E and N55°W) cut the middle Miocene basalt dikes. This faulting may be related to north-south compression and clockwise rotation of western Oregon and southwest Washington associated with the oblique subduction of the Juan De Fuca Plate beneath the North American Plate as suggested by Magill et al. (1981) and Coe and Wells (1982).
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Wheat (Triticum aestivum) is one of the world’s major staple food crops, with flour produced from starchy endosperm being used for breads, cakes, noodles and various other wheat-based foods. The unique ...
Citation Citation
- Title:
- Investigations of gluten proteins from functional and historical perspective
- Author:
- Zhang, Ying
Wheat (Triticum aestivum) is one of the world’s major staple food crops, with flour produced from starchy endosperm being used for breads, cakes, noodles and various other wheat-based foods. The unique bread making properties of wheat are primarily attributed to its gluten-forming storage proteins: gliadins and glutenins. This study investigated the gluten proteins from functional and historical perspectives. The first study examined primarily the functional role of gluten proteins in the outcomes of the standard Falling Number (FN) test. The FN test is used in the grain trade to screen delivered wheat for the presence of pre-harvest sprouting by indirectly measuring α-amylase through it effects on the physical consistency of a cooked flour-water suspension. Grain protein content (GPC) has been implicated as a potential modifier of FN independent of α-amylase or sprout status. In the gluten functionality study, we proposed a protein unfolding and crosslinking model, and hypothesized that gluten proteins with higher molecular weight distributions (MWD) would heatset faster, tightly cover starch granules, restrict water entry, and slow their disintegration. In contrast to our hypothesis, our results showed that samples with lower MWD had faster heatset times than samples with higher MWD according to a controlled heating test. We also hypothesize that increased granularity of hard wheat flour reduces the surface area to volume ratio so the starch granules embedded in the particles need more time to hydrate or swell. However, our results indicated that natural variations in flour particle size from a standard grinding procedure that used a 0.8 mm screen had no impact on FN. The second study looked at potential changes in gluten proteins in a historical set of wheat varieties spanning more than 110 years of production. The wheats were in two sets: soft wheats where there has been no systematic selection for increased dough strength in breeding programs, and hard wheats where there has been a concerted effort to increase overall dough strength over the last century. The sample sets also covered the eras before and after the introduction of the semi-dwarf wheats to the USA. The reason for this investigation is related to the circumstance that wheat is the cause of celiac disease (CD) and is implcated in the disputed condition, non-celiac gluten sensitivity (NCGS). Recently, diagnoses of CD at least have increased and there are suggestions that changes in gluten proteins in the modern era are responsible. Since it is primarily gliadins that trigger CD, it was considered worth investigating whether or not there have been any changes in the composition of gliadins over the last century. Sixty-two soft and 61 hard U.S. high production wheat varieties from 1900 to the present (with one from 1800) were collected and analyzed by RP-HPLC. These varieties were investigated to begin to answer whether wheat breeding for higher dough strength, or the incorporation of dwarfing alleles after the 1960s, was associated with observable changes in gliadin composition. ANOVA showed that there was no significant difference between soft and hard wheats in the relative abundance of α/β-gliadins. However, there were significant differences between hard and soft wheats in the relative abundance of ω- and γ-gliadins. ANOVA also showed that there was no significant difference between tall and dwarf wheats in the relative abundance of any of the three gliadin fractions. The ANOVA results suggested that deliberate breeding for dough strength, as illustrated by the hard versus soft wheat contrast, had not systematically changed the relative abundance of α/β-gliadins across the last 110 years, but had altered the relative abundance of the other two fractions. ANOVA results indicated no change in proportions of the three gliadin fractions after deployment of the dwarfing alleles suggesting the tall to dwarf change was independent of gluten composition. Second order polynomial regression analyses showed that the relative abundance of α/β-gliadins increased until around 1960 then decreased. The changes were more noticeable in the hard wheats. The converse was observed for ?-gliadins. This stepwise change questioned the association between CD increase and breeding for increased dough strength in hard wheats, since the relative abundance of α/β-gliadins did not keep going up, and α-gliadin is considered the major trigger force for CD initiation. In contrast, linear correlation analyses with each of 700, three second long fractions of the RP-HPLC chromatograms suggested that most changes were related to the soft wheat population. The discrepancy between the regression analyses of the three major fractions and the 700 small fractions may be related to the use of linear correlations in the latter when some relationships were clearly non-linear. Overall, our results did not fully support speculations that there have been profound changes in gluten composition related to the dwarfing alleles or selection for increased dough strength in hard wheats.
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1560. [Article] Distribution and life history of the spiny dogfish (Squalus acanthias) off the Oregon and Washington coasts
This study examines the spatial and temporal distribution and life history of the "offshore" component of the Northeastern Pacific spiny dogfish (Squalus acanthias) population. Distribution was examined ...Citation Citation
- Title:
- Distribution and life history of the spiny dogfish (Squalus acanthias) off the Oregon and Washington coasts
- Author:
- Richards, Jaclyn M.
This study examines the spatial and temporal distribution and life history of the "offshore" component of the Northeastern Pacific spiny dogfish (Squalus acanthias) population. Distribution was examined in relation to latitude, depth, the Columbia River plume and large-scale climate changes. Fishery and survey data indicate that the Northeastern Pacific spiny dogfish population has a broad range along the Washington and Oregon coasts, with the highest abundance occurring off the northern Washington and central Oregon coasts. Catches, however, were patchy throughout the 37-year period of available survey data. In terms of depth, the greatest abundances of spiny dogfish were captured in shallow waters (55-184 m). An examination of the influence of the Columbia River plume using a generalized additive model (GAM) indicated that the fish were influenced significantly by the salinity, chlorophyll and surface temperature patterns associated with the plume, preferring the oceanic zone to the plume zone. In contrast, there was no indication that the catch-per-unit-effort of spiny dogfish was influenced by the Pacific Decadal Oscillation (PDO) or the El-Niño (ENSO) over 24-year period of the National Marine Fisheries (NMFS) triennial shelf groundfish survey (1977-2001). The multi-cohort age structure of the population, due to the spiny dogfish's late age at maturity and long lifespan, as well as the low fecundity make it difficult to detect the loss of a single cohort or two when examining abundance trends. Moreover, effects on abundance may be time-lagged, especially if, as is likely, the youngest cohort(s) is the most vulnerable life stage. Their absence would not become evident until they were large enough to have been captured by the survey gear. Sensitive abundance data and/or age-structured data would be needed to identify a pattern. I quantified the age, maturation and fecundity of the spiny dogfish and use these data to develop an age-structured matrix model to examine the sensitivity of the population's growth rate to changes in mortality (i.e. fishing). Female spiny dogfish in this population have an average age at 50% maturity of 28 years and males 20 years. Average length at 50% maturity was 85.0 cm for females and 71.5 cm for males. Female fecundity was extremely low, averaging eight pups per clutch biennially and ranging from four to 14. The number of pups increased with length, but not age. Using these data, a deterministic, female-based model was developed. Asymptotic population growth rate (λ) was determined to be very low, 1.01, and comparable to population growth rates calculated for "coastal" populations. When fishing mortality was incorporated into the model, the fishery was only sustainable when exploitation was low and strict size limits enforced. When fecundity was doubled, the population growth rate increased from 1% to 3% per year. This 33% increase in population growth was equivalent to the effect of a decrease in the age at first maturity of three years. Given that responses to changes in population demographics through shifts in fecundity or spawning frequency are likely constrained, responses would then seem likely to involve changes in age at maturity. These life history traits translate into a low potential population growth and as a consequence high susceptibility to overfishing. My findings indicate that the Northeastern Pacific spiny dogfish are relatively slow growing, late to mature, and have low fecundity and a patchy distribution, with large catches occurring off the northern Washington and central Oregon coasts in shallow waters (55-184 m). These life history traits and distributional patterns are useful in the development of population models to predict responses to environmental fluctuations or increased mortality and thus the management of the population. It is evident from my findings that periodic monitoring is necessary to track possible catch declines off the northern Washington and central Oregon coasts and prevent collapse of the population should it be targeted by a fishery and overfishing occur.