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• 301. [Article] Age systematics of two young en echelon Samoan volcanic trails

  The volcanic origin of the Samoan archipelago can be explained by one of three models, specifically, by a hot spot forming over a mantle plume, by lithospheric extension resulting from complex subduction ...

  Citation × Citation Citation Abstract Copy Title: Age systematics of two young en echelon Samoan volcanic trails Author: Staudigel, Hubert, Hart, Stanley R., Koppers, Anthony A. P., Jackson, Matthew G., Russell, Jamie A., Wright, Dawn J., Roberts, Jed, Konter, Jasper G. The volcanic origin of the Samoan archipelago can be explained by one of three models, specifically, by a hot spot forming over a mantle plume, by lithospheric extension resulting from complex subduction tectonics in the region, or by a combination of these two processes, either acting sequentially or synchronously. In this paper, we present results of 36 high-resolution ⁴⁰Ar/³⁹Ar incremental heating age analyses for the initial (submarine) phase of Samoan volcanoes, ranging from 13.2 Ma for the westernmost Samoan seamounts to 0.27 Ma in the eastern Samoan volcanic province. Taken as a whole, our new age data point to a hot spot origin for the shield-building volcanism in the Samoan lineament, whereby seamounts younger than 5 Ma are consistent with a model of constant 7.1 cm/yr plate motion, analogous to GPS measurements for the Pacific Plate in this region. This makes our new ⁴⁰Ar/³⁹Ar ages of the submarine basalts all older compared to recent absolute plate motion (APM) models by Wessel et al. (2008), which are based on the inversion of twelve independent seamount trails in the Pacific relative to a fixed reference frame of hot spots and which predict faster plate motions of around 9.3 cm/yr in the vicinity of Samoa. The Samoan ages are also older than APM models by Steinberger et al. (2004) taking into account the motion of hot spots in the Pacific alone or globally. The age systematics become more complicated toward the younger end of the Samoan seamount trail, where its morphology bifurcates into two en echelon subtracks, termed the VAI and MALU trends, as they emanate from two eruptive centers at Vailulu'u and Malumalu seamount, respectively. Spaced ~50 km apart, the VAI and MALU trends have distinct geochemical characters and independent but overlapping linear ⁴⁰Ar/³⁹Ar age progressions since 1.5 Ma. These phenomena are not unique to Samoa, as they have been observed at the Hawaiian hot spot, and can be attributed to a geochemical zoning in its underlying mantle source or plume. Moreover, the processes allowing for the emergence of two distinct eruptive centers in the Samoan archipelago, the stepped offset of these subtracks, and their slight obliqueness with respect to the overall seamount trail orientation may very well be controlled by local tectonics, stresses, and extension, also causing the rejuvenated volcanism on the main islands of Savai'i, Upolu, and Tutuila since 0.4 Ma. Title: Age systematics of two young en echelon Samoan volcanic trails Author: Staudigel, Hubert, Hart, Stanley R., Koppers, Anthony A. P., Jackson, Matthew G., Russell, Jamie A., Wright, Dawn J., Roberts, Jed, Konter, Jasper G. The volcanic origin of the Samoan archipelago can be explained by one of three models, specifically, by a hot spot forming over a mantle plume, by lithospheric extension resulting from complex subduction tectonics in the region, or by a combination of these two processes, either acting sequentially or synchronously. In this paper, we present results of 36 high-resolution ⁴⁰Ar/³⁹Ar incremental heating age analyses for the initial (submarine) phase of Samoan volcanoes, ranging from 13.2 Ma for the westernmost Samoan seamounts to 0.27 Ma in the eastern Samoan volcanic province. Taken as a whole, our new age data point to a hot spot origin for the shield-building volcanism in the Samoan lineament, whereby seamounts younger than 5 Ma are consistent with a model of constant 7.1 cm/yr plate motion, analogous to GPS measurements for the Pacific Plate in this region. This makes our new ⁴⁰Ar/³⁹Ar ages of the submarine basalts all older compared to recent absolute plate motion (APM) models by Wessel et al. (2008), which are based on the inversion of twelve independent seamount trails in the Pacific relative to a fixed reference frame of hot spots and which predict faster plate motions of around 9.3 cm/yr in the vicinity of Samoa. The Samoan ages are also older than APM models by Steinberger et al. (2004) taking into account the motion of hot spots in the Pacific alone or globally. The age systematics become more complicated toward the younger end of the Samoan seamount trail, where its morphology bifurcates into two en echelon subtracks, termed the VAI and MALU trends, as they emanate from two eruptive centers at Vailulu'u and Malumalu seamount, respectively. Spaced ~50 km apart, the VAI and MALU trends have distinct geochemical characters and independent but overlapping linear ⁴⁰Ar/³⁹Ar age progressions since 1.5 Ma. These phenomena are not unique to Samoa, as they have been observed at the Hawaiian hot spot, and can be attributed to a geochemical zoning in its underlying mantle source or plume. Moreover, the processes allowing for the emergence of two distinct eruptive centers in the Samoan archipelago, the stepped offset of these subtracks, and their slight obliqueness with respect to the overall seamount trail orientation may very well be controlled by local tectonics, stresses, and extension, also causing the rejuvenated volcanism on the main islands of Savai'i, Upolu, and Tutuila since 0.4 Ma. Close

• 302. [Article] The CO2 tracer clock for the Tropical Tropopause Layer

  Observations of CO2 were made in the upper troposphere and lower stratosphere in the deep tropics in order to determine the patterns of large-scale vertical transport and age of air in the Tropical Tropopause ...

  Citation × Citation Citation Abstract Copy Title: The CO2 tracer clock for the Tropical Tropopause Layer Author: Gottlieb, E. W., Atlas, E. L., Matross, D. M., Conway, T. J., Twohy, Cynthia, Chow, V. Y, Gao, R.-S., Bui, T. P., Bright, A., Curran, D. J., Park, S., Daube, B. C., Jimenez, R., Wofsy, S. C., Pfister, L. Observations of CO2 were made in the upper troposphere and lower stratosphere in the deep tropics in order to determine the patterns of large-scale vertical transport and age of air in the Tropical Tropopause Layer (TTL). Flights aboard the NASA WB-57F aircraft over Central America and adjacent ocean areas took place in January and February, 2004 (Pre-AURA Validation Experiment, Pre-AVE) and 2006 (Costa Rice AVE, CR-AVE), and for the same flight dates of 2006, aboard the Proteus aircraft from the surface to 15 km over Darwin, Australia (Tropical Warm Pool International Cloud Experiment, TWPICE). The data demonstrate that the TTL is composed of two layers with distinctive features: (1) the lower TTL, 350–360 K (potential temperature(θ); approximately 12–14 km), is subject to inputs of convective outflows, as indicated by layers of variable CO2 concentrations, with air parcels of zero age distributed throughout the layer; (2) the upper TTL, from θ=~360 K to ~390 K (14–18 km), ascends slowly and ages uniformly, as shown by a linear decline in CO2 mixing ratio tightly correlated with altitude, associated with increasing age. This division is confirmed by ensemble trajectory analysis. The CO2 concentration at the level of 360 K was 380.0(±0.2) ppmv, indistinguishable from surface site values in the Intertropical Convergence Zone (ITCZ) for the flight dates. Values declined with altitude to 379.2(±0.2) ppmv at 390 K, implying that air in the upper TTL monotonically ages while ascending. In combination with the winter slope of the CO2 seasonal cycle (+10.8±0.4 ppmv/yr), the vertical gradient of –0.78 (±0.09) ppmv gives a mean age of 26(±3) days for the air at 390 K and a mean ascent rate of 1.5(±0.3) mm s−1. The TTL near 360 K in the Southern Hemisphere over Australia is very close in CO2 composition to the TTL in the Northern Hemisphere over Costa Rica, with strong contrasts emerging at lower altitudes (<360 K). Both Pre-AVE and CR-AVE CO2 observed unexpected input from deep convection over Amazônia deep into the TTL. The CO2 data confirm the operation of a highly accurate tracer clock in the TTL that provides a direct measure of the ascent rate of the TTL and of the age of air entering the stratosphere. Title: The CO2 tracer clock for the Tropical Tropopause Layer Author: Gottlieb, E. W., Atlas, E. L., Matross, D. M., Conway, T. J., Twohy, Cynthia, Chow, V. Y, Gao, R.-S., Bui, T. P., Bright, A., Curran, D. J., Park, S., Daube, B. C., Jimenez, R., Wofsy, S. C., Pfister, L. Observations of CO2 were made in the upper troposphere and lower stratosphere in the deep tropics in order to determine the patterns of large-scale vertical transport and age of air in the Tropical Tropopause Layer (TTL). Flights aboard the NASA WB-57F aircraft over Central America and adjacent ocean areas took place in January and February, 2004 (Pre-AURA Validation Experiment, Pre-AVE) and 2006 (Costa Rice AVE, CR-AVE), and for the same flight dates of 2006, aboard the Proteus aircraft from the surface to 15 km over Darwin, Australia (Tropical Warm Pool International Cloud Experiment, TWPICE). The data demonstrate that the TTL is composed of two layers with distinctive features: (1) the lower TTL, 350–360 K (potential temperature(θ); approximately 12–14 km), is subject to inputs of convective outflows, as indicated by layers of variable CO2 concentrations, with air parcels of zero age distributed throughout the layer; (2) the upper TTL, from θ=~360 K to ~390 K (14–18 km), ascends slowly and ages uniformly, as shown by a linear decline in CO2 mixing ratio tightly correlated with altitude, associated with increasing age. This division is confirmed by ensemble trajectory analysis. The CO2 concentration at the level of 360 K was 380.0(±0.2) ppmv, indistinguishable from surface site values in the Intertropical Convergence Zone (ITCZ) for the flight dates. Values declined with altitude to 379.2(±0.2) ppmv at 390 K, implying that air in the upper TTL monotonically ages while ascending. In combination with the winter slope of the CO2 seasonal cycle (+10.8±0.4 ppmv/yr), the vertical gradient of –0.78 (±0.09) ppmv gives a mean age of 26(±3) days for the air at 390 K and a mean ascent rate of 1.5(±0.3) mm s−1. The TTL near 360 K in the Southern Hemisphere over Australia is very close in CO2 composition to the TTL in the Northern Hemisphere over Costa Rica, with strong contrasts emerging at lower altitudes (<360 K). Both Pre-AVE and CR-AVE CO2 observed unexpected input from deep convection over Amazônia deep into the TTL. The CO2 data confirm the operation of a highly accurate tracer clock in the TTL that provides a direct measure of the ascent rate of the TTL and of the age of air entering the stratosphere. Close

• 303. [Article] Early Ocean Dispersal Patterns of Columbia River Chinook and Coho Salmon

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Taylor ...

  Citation × Citation Citation Abstract Copy Title: Early Ocean Dispersal Patterns of Columbia River Chinook and Coho Salmon Author: Orsi, J. A., Morris, J. F. T., Teel, D. J., Farley, E. V., Jr., Weitkamp, L. A., Trudel, M., Fisher, J. P., Sweeting, R. M., Hinton, S. A., Thiess, M. E. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Taylor & Francis and can be found at: http://www.tandfonline.com/toc/utaf20/current#.Uz8B2_Pn-Hs. Title: Early Ocean Dispersal Patterns of Columbia River Chinook and Coho Salmon Author: Orsi, J. A., Morris, J. F. T., Teel, D. J., Farley, E. V., Jr., Weitkamp, L. A., Trudel, M., Fisher, J. P., Sweeting, R. M., Hinton, S. A., Thiess, M. E. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Taylor & Francis and can be found at: http://www.tandfonline.com/toc/utaf20/current#.Uz8B2_Pn-Hs. Close

• 304. [Article] First Direct Evidence for Natal Wintering Ground Fidelity and Estimate of Juvenile Survival in the New Zealand Southern Right Whale Eubalaena australis

  Supporting information is available online at: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0146590#sec014

  Citation × Citation Citation Abstract Copy Title: First Direct Evidence for Natal Wintering Ground Fidelity and Estimate of Juvenile Survival in the New Zealand Southern Right Whale Eubalaena australis Author: Patenaude, N. J., Fewster, R. M., Carroll, E. L., Baker, C. S., Childerhouse, S. J., Boren, L. Supporting information is available online at: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0146590#sec014 Title: First Direct Evidence for Natal Wintering Ground Fidelity and Estimate of Juvenile Survival in the New Zealand Southern Right Whale Eubalaena australis Author: Patenaude, N. J., Fewster, R. M., Carroll, E. L., Baker, C. S., Childerhouse, S. J., Boren, L. Supporting information is available online at: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0146590#sec014 Close

• 305. [Article] Hydrogeologic field investigation and groundwater flow model of the southern Willamette Valley, Oregon

  Elevated groundwater nitrate (NO3 -) concentrations in the Southern Willamette Valley (SWV) caused the Oregon Department of Environmental Quality (ODEQ) to declare a Groundwater Management Area (GWMA) ...

  Citation × Citation Citation Abstract Copy Title: Hydrogeologic field investigation and groundwater flow model of the southern Willamette Valley, Oregon Author: Craner, Jeremy D. Elevated groundwater nitrate (NO3 -) concentrations in the Southern Willamette Valley (SWV) caused the Oregon Department of Environmental Quality (ODEQ) to declare a Groundwater Management Area (GWMA) in Spring, 2004. To better understand direction of groundwater flow, groundwater age, and nitrate transport pathways of the SWV we developed a steady-state numerical groundwater flow model using MODFLOW with MODPATH. Model development was supplemented by field investigations of local outcrops, pump and slug tests, and laboratory analyses to determine groundwater age and groundwater chemistry. Field work included the construction/collection of cross-sections and stratigraphic columns; 12 slug tests and 3 pump tests to determine hydraulic conductivity and storativity; 10 groundwater ages using CFC-11, CFC-12, and CFC-113; 3 wells instrumented to collect long-term continuous water level measurements; 42 wells selected for quarterly manual water level measurements; and 14 groundwater samples to determine pH, dissolved oxygen, specific electrical conductance, chloride, sulfate, and nitrate concentrations. Slug tests determined horizontal hydraulic conductivities (Kx) from 4.19 x 10-8 m/s to 4.62 x 10-4 m/s. Pump tests determined Kx-values from 3.59 x 10-4 m/s to 7.22 x 10-3 m/s, vertical hydraulic conductivities (Kv) from 3.48 x 10-6 m/s to 3.84 x 10-6 m/s, and storage coefficients from 0.05 to 0.15. Groundwater age ranged from 13 years to >50 years, with the greatest ages resulting from wells that penetrated the semi-confining Willamette Silt. Groundwater ages were compared to model particle travel times using MODPATH and used as calibration targets. Groundwater ages along with nitrate, chloride, sulfate, and dissolved oxygen concentrations were used to reconstruct past contaminant loading and observe data trends. Spatial distributions of hydraulic conductivity were estimated using wells with specific capacity data and an empirical relationship (T = 158.48sc, where T = transmissivity (ft2/d) and sc = (gal/min/ft); R2 = 0.61) between wells in the study area that contained both specific capacity and aquifer test data. The calibrated groundwater flow model is intended to help make management decisions, establish monitoring programs, and to be used as an outreach education tool. Model simulations were run in key areas to demonstrate model capabilities and create visual aids for outreach education. This study suggests it may take 10’s of years to see measurable declines of groundwater nitrate in some locations. It is our hope that educating stakeholders about local groundwater flow along with stressing the use of Best Management Practices (BMPs) will result in better decision making and lead to a reduction of groundwater nitrate concentration in the SWV. Title: Hydrogeologic field investigation and groundwater flow model of the southern Willamette Valley, Oregon Author: Craner, Jeremy D. Elevated groundwater nitrate (NO3 -) concentrations in the Southern Willamette Valley (SWV) caused the Oregon Department of Environmental Quality (ODEQ) to declare a Groundwater Management Area (GWMA) in Spring, 2004. To better understand direction of groundwater flow, groundwater age, and nitrate transport pathways of the SWV we developed a steady-state numerical groundwater flow model using MODFLOW with MODPATH. Model development was supplemented by field investigations of local outcrops, pump and slug tests, and laboratory analyses to determine groundwater age and groundwater chemistry. Field work included the construction/collection of cross-sections and stratigraphic columns; 12 slug tests and 3 pump tests to determine hydraulic conductivity and storativity; 10 groundwater ages using CFC-11, CFC-12, and CFC-113; 3 wells instrumented to collect long-term continuous water level measurements; 42 wells selected for quarterly manual water level measurements; and 14 groundwater samples to determine pH, dissolved oxygen, specific electrical conductance, chloride, sulfate, and nitrate concentrations. Slug tests determined horizontal hydraulic conductivities (Kx) from 4.19 x 10-8 m/s to 4.62 x 10-4 m/s. Pump tests determined Kx-values from 3.59 x 10-4 m/s to 7.22 x 10-3 m/s, vertical hydraulic conductivities (Kv) from 3.48 x 10-6 m/s to 3.84 x 10-6 m/s, and storage coefficients from 0.05 to 0.15. Groundwater age ranged from 13 years to >50 years, with the greatest ages resulting from wells that penetrated the semi-confining Willamette Silt. Groundwater ages were compared to model particle travel times using MODPATH and used as calibration targets. Groundwater ages along with nitrate, chloride, sulfate, and dissolved oxygen concentrations were used to reconstruct past contaminant loading and observe data trends. Spatial distributions of hydraulic conductivity were estimated using wells with specific capacity data and an empirical relationship (T = 158.48sc, where T = transmissivity (ft2/d) and sc = (gal/min/ft); R2 = 0.61) between wells in the study area that contained both specific capacity and aquifer test data. The calibrated groundwater flow model is intended to help make management decisions, establish monitoring programs, and to be used as an outreach education tool. Model simulations were run in key areas to demonstrate model capabilities and create visual aids for outreach education. This study suggests it may take 10’s of years to see measurable declines of groundwater nitrate in some locations. It is our hope that educating stakeholders about local groundwater flow along with stressing the use of Best Management Practices (BMPs) will result in better decision making and lead to a reduction of groundwater nitrate concentration in the SWV. Close

• 306. [Article] The effect of hopping technology on lager beer flavor and flavor stability and the impact of polyphenols on lager beer flavor and physical stability

  Beer is one of the most extensively consumed beverages world-wide and it is almost always brewed with hops (Humulus lupulus, L.). Hops provide beer with bitterness, aroma, flavor and texture and also enhance ...

  Citation × Citation Citation Abstract Copy Title: The effect of hopping technology on lager beer flavor and flavor stability and the impact of polyphenols on lager beer flavor and physical stability Author: Aron, Patricia M. Beer is one of the most extensively consumed beverages world-wide and it is almost always brewed with hops (Humulus lupulus, L.). Hops provide beer with bitterness, aroma, flavor and texture and also enhance specific beer properties such as foam stability, clarity (colloidal stability), color, flavor stability and microbial stability. Hops are a dioecious species, with female plants producing the hop strobilus (cone). The cone is an inflorescence, which is the entire part of the plant that holds the flowers. Hop cones contain lupulin glands (the source of the hop bittering resins), essential oils, and polyphenols (prenylflavonoids). Beer prenylflavonoids such as the flavan-3-ols and their condensed products, the proanthocyanidins, represent a class of readily oxidizable compounds capable of hindering or preventing the oxidation of other molecules present in beer. Flavan-3-ols and proanthocyanidins have recently gained significant consideration as potential beer flavor modifiers and/or stabilizers. However their roles in beer flavor stability have not yet been fully realized. In this study polyphenols were extracted from spent hop (Humulus lupulus L. cv Galena) solid materials and dosed into commercial lager beers. Chemical analysis of the fresh and aged beers confirmed an anti-staling effect of the dosed polyphenol extract as measured by antioxidant capacity assays: FRAP, DPPH• and ESR. The polyphenol rich extract was subjected to phloroglucinolysis and analyzed via reverse-phased chromatography/mass spectroscopy-electrospray ionization (RP-HPLC/MS-ESI) to determine flavonoid content. C-18 RP-HPLC analysis of the extract revealed that it was 99% phenolic in nature, with a procyanidin mean degree of polymerization (mDP) of 2.72. Based on these findings beers were subsequently brewed with and without hop products (Humulus lupulus L. cv Galena) to target the effect of the complete hop (pellets), hop bittering acids only (CO₂ extract), hop polyphenols only (spent hop solids) and no hop components (Control) on beer flavor and flavor stability. Spent Hop and Pellet Hop beers scored highest in antioxidant potential as measured by the FRAP assay, howeer ESR results were contradictory. Even after force-aging, Pellet hopped beers were lowest in total aldehydes and Control beers were highest in total aldehydes, indicating a protective effect for whole hop products on staling aldehyde formation. Sensorially, the Spent Hop and Pellet Hop beers were characterized by high Piney and Tropical fruit notes, with significant increases occurring after force-aging. The Control beers were rated as being higher in Overall Aroma Intensity, and were judged as being high in Cardboard aroma after force-aging. Preliminary findings from the brewing trials indicated that significant changes in polyphenol levels occur during accelerated aging. The brewing trial was therefore repeated and beers were profiled for phenolic content and investigated for changes in phenolic content during aging. Beer polyphenols were extracted with Sephadex LH20 resin and subjected to phloroglucinolysis to reveal subunit composition and proanthocyanidin mDP. Although the sephadex extracts were phenolic in nature, proanthocyanidins only accounted for up to 2% of the total phenolic material. Total flavanoid and proanthocyanidin content of the beers increased initially during storage, with eventual decreases occurring after 6 weeks of storage at 30°C. Beers high in hop polyphenols did not suppress the loss of iso-alpha acids during aging and were once again assessed as least flavor stable of the beers by ESR T150. Title: The effect of hopping technology on lager beer flavor and flavor stability and the impact of polyphenols on lager beer flavor and physical stability Author: Aron, Patricia M. Beer is one of the most extensively consumed beverages world-wide and it is almost always brewed with hops (Humulus lupulus, L.). Hops provide beer with bitterness, aroma, flavor and texture and also enhance specific beer properties such as foam stability, clarity (colloidal stability), color, flavor stability and microbial stability. Hops are a dioecious species, with female plants producing the hop strobilus (cone). The cone is an inflorescence, which is the entire part of the plant that holds the flowers. Hop cones contain lupulin glands (the source of the hop bittering resins), essential oils, and polyphenols (prenylflavonoids). Beer prenylflavonoids such as the flavan-3-ols and their condensed products, the proanthocyanidins, represent a class of readily oxidizable compounds capable of hindering or preventing the oxidation of other molecules present in beer. Flavan-3-ols and proanthocyanidins have recently gained significant consideration as potential beer flavor modifiers and/or stabilizers. However their roles in beer flavor stability have not yet been fully realized. In this study polyphenols were extracted from spent hop (Humulus lupulus L. cv Galena) solid materials and dosed into commercial lager beers. Chemical analysis of the fresh and aged beers confirmed an anti-staling effect of the dosed polyphenol extract as measured by antioxidant capacity assays: FRAP, DPPH• and ESR. The polyphenol rich extract was subjected to phloroglucinolysis and analyzed via reverse-phased chromatography/mass spectroscopy-electrospray ionization (RP-HPLC/MS-ESI) to determine flavonoid content. C-18 RP-HPLC analysis of the extract revealed that it was 99% phenolic in nature, with a procyanidin mean degree of polymerization (mDP) of 2.72. Based on these findings beers were subsequently brewed with and without hop products (Humulus lupulus L. cv Galena) to target the effect of the complete hop (pellets), hop bittering acids only (CO₂ extract), hop polyphenols only (spent hop solids) and no hop components (Control) on beer flavor and flavor stability. Spent Hop and Pellet Hop beers scored highest in antioxidant potential as measured by the FRAP assay, howeer ESR results were contradictory. Even after force-aging, Pellet hopped beers were lowest in total aldehydes and Control beers were highest in total aldehydes, indicating a protective effect for whole hop products on staling aldehyde formation. Sensorially, the Spent Hop and Pellet Hop beers were characterized by high Piney and Tropical fruit notes, with significant increases occurring after force-aging. The Control beers were rated as being higher in Overall Aroma Intensity, and were judged as being high in Cardboard aroma after force-aging. Preliminary findings from the brewing trials indicated that significant changes in polyphenol levels occur during accelerated aging. The brewing trial was therefore repeated and beers were profiled for phenolic content and investigated for changes in phenolic content during aging. Beer polyphenols were extracted with Sephadex LH20 resin and subjected to phloroglucinolysis to reveal subunit composition and proanthocyanidin mDP. Although the sephadex extracts were phenolic in nature, proanthocyanidins only accounted for up to 2% of the total phenolic material. Total flavanoid and proanthocyanidin content of the beers increased initially during storage, with eventual decreases occurring after 6 weeks of storage at 30°C. Beers high in hop polyphenols did not suppress the loss of iso-alpha acids during aging and were once again assessed as least flavor stable of the beers by ESR T150. Close

• 307. [Article] A comparison of the effect of computer-assisted-instruction and same-age peer-tutoring on math achievement of fourth grade students

  A pretest-posttest design was used to compare the effectiveness of computer-assisted-instruction (CAI) drill and practice with the effectiveness of same-age peer-tutor drill and practice on promoting mastery ...

  Citation × Citation Citation Abstract Copy Title: A comparison of the effect of computer-assisted-instruction and same-age peer-tutoring on math achievement of fourth grade students Author: Pflug, Elizabeth A. A pretest-posttest design was used to compare the effectiveness of computer-assisted-instruction (CAI) drill and practice with the effectiveness of same-age peer-tutor drill and practice on promoting mastery of multiplication facts. The subjects were students from three, fourth grade classes in the Reedville School District of Aloha, Oregon. Two fourth grade classes were randomly assigned to two treatment groups: CAI and same-age peer-tutoring. A third class was designated as a control group. Students in the CAI group drilled on multiplication facts independently at a computer for 10 minutes per day for 25 days. Students in the same-age peer-tutor group tutored classmates using multiplication flashcards for 5 minutes and were tutored for an additional 5 minutes for a total of 10 minutes per day for 25 days. The control group received traditional math instruction consisting of daily, one-minute, mastery tests. Drill and practice was independent and self-paced. Treatment consisted of drill and practice on multiplication facts with multipliers 0-9 and multiplicands 6-9. The pretest and posttest were computer-constructed criterion tests consisting of randomly selected multiplication facts from the treatment set. Fifty-two students began the treatment. Forty-five students completed treatment and the posttest. Analysis of variance and Tukey's multiple comparison test showed a significant difference between the CAI group (x̄ = 48.00) and control group (x̄̄ = 67.60) on the pretest. However, on the posttest, analysis of covariance revealed no significant difference among the groups (p = .05). Therefore, the null hypotheses for the study were accepted. The hypotheses predicted there would be no significant difference between the groups' mean math scores on the posttest. Although the study did not identify either CAI or same-age peer-tutoring drill and practice as more effective than the other, it did show both strategies to be equally effective in promoting mastery of basic math facts. The adjusted group means were CAI: 93.97 and same-age peer-tutoring: 93.43. In finding the two strategies to be equally effective, the study identified same-age peer-tutoring as a cost-effective alternative to CAI drill and practice. The findings have implications for staff development, curriculum planning, and for teachers' selection of drill and practice strategies. Title: A comparison of the effect of computer-assisted-instruction and same-age peer-tutoring on math achievement of fourth grade students Author: Pflug, Elizabeth A. A pretest-posttest design was used to compare the effectiveness of computer-assisted-instruction (CAI) drill and practice with the effectiveness of same-age peer-tutor drill and practice on promoting mastery of multiplication facts. The subjects were students from three, fourth grade classes in the Reedville School District of Aloha, Oregon. Two fourth grade classes were randomly assigned to two treatment groups: CAI and same-age peer-tutoring. A third class was designated as a control group. Students in the CAI group drilled on multiplication facts independently at a computer for 10 minutes per day for 25 days. Students in the same-age peer-tutor group tutored classmates using multiplication flashcards for 5 minutes and were tutored for an additional 5 minutes for a total of 10 minutes per day for 25 days. The control group received traditional math instruction consisting of daily, one-minute, mastery tests. Drill and practice was independent and self-paced. Treatment consisted of drill and practice on multiplication facts with multipliers 0-9 and multiplicands 6-9. The pretest and posttest were computer-constructed criterion tests consisting of randomly selected multiplication facts from the treatment set. Fifty-two students began the treatment. Forty-five students completed treatment and the posttest. Analysis of variance and Tukey's multiple comparison test showed a significant difference between the CAI group (x̄ = 48.00) and control group (x̄̄ = 67.60) on the pretest. However, on the posttest, analysis of covariance revealed no significant difference among the groups (p = .05). Therefore, the null hypotheses for the study were accepted. The hypotheses predicted there would be no significant difference between the groups' mean math scores on the posttest. Although the study did not identify either CAI or same-age peer-tutoring drill and practice as more effective than the other, it did show both strategies to be equally effective in promoting mastery of basic math facts. The adjusted group means were CAI: 93.97 and same-age peer-tutoring: 93.43. In finding the two strategies to be equally effective, the study identified same-age peer-tutoring as a cost-effective alternative to CAI drill and practice. The findings have implications for staff development, curriculum planning, and for teachers' selection of drill and practice strategies. Close

• 308. [Article] Structural and functional comparison of human-impacted and natural forest landscapes in the western Cascades of Oregon

  This study compared effects of human and natural wildfire disturbance on age class distribution and associated ecosystem properties of forests in a 15,670 km2 area of the western Cascades of Oregon. The ...

  Citation × Citation Citation Abstract Copy Title: Structural and functional comparison of human-impacted and natural forest landscapes in the western Cascades of Oregon Author: Pennington, Deana D. This study compared effects of human and natural wildfire disturbance on age class distribution and associated ecosystem properties of forests in a 15,670 km2 area of the western Cascades of Oregon. The study site is characterized by three forest use types: low elevation, intensively harvested private industrial lands; mid elevation partially harvested public forest lands; and high elevation wilderness lands. Hypothetical landscapes were constructed, representing wildfire conditions, the current (1995) condition, and forest management strategies. The spatial pattern of forests in each landscape was depicted by the distribution of four forest age classes (0-30,31-80,81-200, and 201+ years). Wildfire-affected forests were simulated for 3000-year periods using an existing model with six alternate parameterizations obtained from fire history studies. Forest patterns on the 1995 landscape were obtained from classified remotely sensed imagery. Three landscapes representing hypothetical forest management strategies were constructed: 1) riparian buffers, 2) reserve allocations, and 3) multi-age rotation harvests. Forest age class amounts, spatial distribution, and arrangement were compared between wildfire-affected, 1995, and managed landscapes. Wood production, carbon storage, water yield, and species diversity of each landscape were evaluated using simple measures from empirical studies relating forest structural patterns to ecosystem properties. Comparison of the 1995 landscape with simulated wildfire-affected landscapes indicates that private industrial lands in 1995 had more young forest, whereas wilderness lands had more old forest, than most, or all, simulated wildfire conditions. Because private industrial and wilderness areas deviate from the range of natural (wildfire-affected) variability in opposite directions, the study area as a whole is within the probable range of natural variability over the past few millennia. Forest ages classes on public non-wilderness lands were within the range of simulated wildfire-affected landscapes. Ecosystem properties of the current and managed landscapes were within the range of variability of those properties in the simulated wildfire-affected landscapes. Given the caveats imposed by the simplistic assumptions, some ecosystem properties appear to be sensitive to the arrangement of forest age classes. Future studies would benefit from the use of structurally based, rather than age-based, forest classes, for evaluating forest pattern effects on ecosystem properties. Title: Structural and functional comparison of human-impacted and natural forest landscapes in the western Cascades of Oregon Author: Pennington, Deana D. This study compared effects of human and natural wildfire disturbance on age class distribution and associated ecosystem properties of forests in a 15,670 km2 area of the western Cascades of Oregon. The study site is characterized by three forest use types: low elevation, intensively harvested private industrial lands; mid elevation partially harvested public forest lands; and high elevation wilderness lands. Hypothetical landscapes were constructed, representing wildfire conditions, the current (1995) condition, and forest management strategies. The spatial pattern of forests in each landscape was depicted by the distribution of four forest age classes (0-30,31-80,81-200, and 201+ years). Wildfire-affected forests were simulated for 3000-year periods using an existing model with six alternate parameterizations obtained from fire history studies. Forest patterns on the 1995 landscape were obtained from classified remotely sensed imagery. Three landscapes representing hypothetical forest management strategies were constructed: 1) riparian buffers, 2) reserve allocations, and 3) multi-age rotation harvests. Forest age class amounts, spatial distribution, and arrangement were compared between wildfire-affected, 1995, and managed landscapes. Wood production, carbon storage, water yield, and species diversity of each landscape were evaluated using simple measures from empirical studies relating forest structural patterns to ecosystem properties. Comparison of the 1995 landscape with simulated wildfire-affected landscapes indicates that private industrial lands in 1995 had more young forest, whereas wilderness lands had more old forest, than most, or all, simulated wildfire conditions. Because private industrial and wilderness areas deviate from the range of natural (wildfire-affected) variability in opposite directions, the study area as a whole is within the probable range of natural variability over the past few millennia. Forest ages classes on public non-wilderness lands were within the range of simulated wildfire-affected landscapes. Ecosystem properties of the current and managed landscapes were within the range of variability of those properties in the simulated wildfire-affected landscapes. Given the caveats imposed by the simplistic assumptions, some ecosystem properties appear to be sensitive to the arrangement of forest age classes. Future studies would benefit from the use of structurally based, rather than age-based, forest classes, for evaluating forest pattern effects on ecosystem properties. Close

• 309. [Article] Requisite family living competencies for high school graduates of Oregon, as perceived by participants of public health prenatal classes

  The main objective of this study was to identify family life competencies needed by high school graduates, as perceived by a majority of respondents. In addition, the null hypothesis tested was: that age, ...

  Citation × Citation Citation Abstract Copy Title: Requisite family living competencies for high school graduates of Oregon, as perceived by participants of public health prenatal classes Author: Taylor, Carolyn Diane The main objective of this study was to identify family life competencies needed by high school graduates, as perceived by a majority of respondents. In addition, the null hypothesis tested was: that age, sex, and educational level are each independent of response on each individual competency statement. Testing was done at the 5% level of significance. The questionnaire was developed through a synthesis of goals stated in twelve family life curriculum guides published since 1965. A working draft of the questionnaire was developmentally tested with three high school seniors and three mothers of teenagers. The survey instrument included provisions for indicating personal data, and offered four categories of "Essential", "Necessary", "Permissible", and "Unimportant", for participants to respond to nine family life topics and seventy competency statements. The population included those couples and individuals voluntarily attending county public health prenatal classes in western Oregon. Data were collected from all five counties with an on-going program. One hundred forty-seven usable questionnaires were obtained. Four instruments were disregarded because of incomplete personal data. Participants in the study ranged from 16 to 45 years of age with a mean age of 25, and with 46.94 percent of the people in the 25 to 29 age group. Males numbered 56 (38. 10 percent) in the participating group, with 91 (61.90 percent) females. Grouped educational levels revealed 27. 21 percent having more than 16 years of education and the groups with 12 years and with 13-15 years of education each being 26. 53 percent of the total sample. Frequency counts and percentages of the total sample indicating favorable responses, were computed and presented for each of the 9 family life topics and 70 competency statements. All 9 family life topics and 64 of the 70 competency statements received a majority (over 50 percent) of favorable responses. Chi-square tests were computed on each item of the questionnaire to test the null hypothesis that age, sex, and educational level are each independent of response. The null hypothesis was rejected for age, in seven instances. Most cases showed younger people responding favorably more often than expected and older people responding less favorably more often than expected. The null hypothesis was rejected for sex in four instances, with males responding less favorably more often and females more favorably more often than expected. The null hypothesis for educational level was rejected in nine instances. More educated people tended to respond less favorably more often and less educated people tended to respond more favorably more often than expected. Implications of the study for the family living curriculum in Oregon secondary schools, as indicated in the opinions of the respondents, are as follows: 1. Family life topics of communicating, understanding yourself, relating to others, understanding sex, being a family member, parenthood, selecting a mate, marriage, and the family relating to the community would be valuable in the family life curriculum. 2. It seems necessary that family life education topics stress making decisions, solving problems, resolving conflicts, and coping with situations. 3. It seems reasonable that sixty-four of the family life competencies identified in this study be incorporated in programs designed to prepare students for their life role as a family member. The sample of expectant parents was a biased group. On speculation it seems that the sample could be quite concerned about the topic and competencies of parenthood. In view of this, the following recommendations for future studies are made: 1. High school students, young married couples not expecting children, and middle aged couples need to be surveyed to identify family life competencies. 2. Learning experiences need to be developed for family life competencies. Title: Requisite family living competencies for high school graduates of Oregon, as perceived by participants of public health prenatal classes Author: Taylor, Carolyn Diane The main objective of this study was to identify family life competencies needed by high school graduates, as perceived by a majority of respondents. In addition, the null hypothesis tested was: that age, sex, and educational level are each independent of response on each individual competency statement. Testing was done at the 5% level of significance. The questionnaire was developed through a synthesis of goals stated in twelve family life curriculum guides published since 1965. A working draft of the questionnaire was developmentally tested with three high school seniors and three mothers of teenagers. The survey instrument included provisions for indicating personal data, and offered four categories of "Essential", "Necessary", "Permissible", and "Unimportant", for participants to respond to nine family life topics and seventy competency statements. The population included those couples and individuals voluntarily attending county public health prenatal classes in western Oregon. Data were collected from all five counties with an on-going program. One hundred forty-seven usable questionnaires were obtained. Four instruments were disregarded because of incomplete personal data. Participants in the study ranged from 16 to 45 years of age with a mean age of 25, and with 46.94 percent of the people in the 25 to 29 age group. Males numbered 56 (38. 10 percent) in the participating group, with 91 (61.90 percent) females. Grouped educational levels revealed 27. 21 percent having more than 16 years of education and the groups with 12 years and with 13-15 years of education each being 26. 53 percent of the total sample. Frequency counts and percentages of the total sample indicating favorable responses, were computed and presented for each of the 9 family life topics and 70 competency statements. All 9 family life topics and 64 of the 70 competency statements received a majority (over 50 percent) of favorable responses. Chi-square tests were computed on each item of the questionnaire to test the null hypothesis that age, sex, and educational level are each independent of response. The null hypothesis was rejected for age, in seven instances. Most cases showed younger people responding favorably more often than expected and older people responding less favorably more often than expected. The null hypothesis was rejected for sex in four instances, with males responding less favorably more often and females more favorably more often than expected. The null hypothesis for educational level was rejected in nine instances. More educated people tended to respond less favorably more often and less educated people tended to respond more favorably more often than expected. Implications of the study for the family living curriculum in Oregon secondary schools, as indicated in the opinions of the respondents, are as follows: 1. Family life topics of communicating, understanding yourself, relating to others, understanding sex, being a family member, parenthood, selecting a mate, marriage, and the family relating to the community would be valuable in the family life curriculum. 2. It seems necessary that family life education topics stress making decisions, solving problems, resolving conflicts, and coping with situations. 3. It seems reasonable that sixty-four of the family life competencies identified in this study be incorporated in programs designed to prepare students for their life role as a family member. The sample of expectant parents was a biased group. On speculation it seems that the sample could be quite concerned about the topic and competencies of parenthood. In view of this, the following recommendations for future studies are made: 1. High school students, young married couples not expecting children, and middle aged couples need to be surveyed to identify family life competencies. 2. Learning experiences need to be developed for family life competencies. Close

• 310. [Article] Stand development of Cordia alliodora (Boraginaceae), a neotropical secondary forest tree in northern Costa Rica (1992-1996)

  Cordia alliodora is used for reforestation programs and farm income in northern Costa Rica. This study investigated: 1) responses of C. alliodora associated with stand density, or trees/ha (TPH), and 2) ...

  Citation × Citation Citation Abstract Copy Title: Stand development of Cordia alliodora (Boraginaceae), a neotropical secondary forest tree in northern Costa Rica (1992-1996) Author: Hummel, Susan Stevens Cordia alliodora is used for reforestation programs and farm income in northern Costa Rica. This study investigated: 1) responses of C. alliodora associated with stand density, or trees/ha (TPH), and 2) plant diversity and biomass in the understory of C. alliodora plantations. Three Nelder plots, 31 temporary plots and 6 plantations in northern Costa Rica were measured between 1992-1996. The plots included monocultures of C. alliodora (MONO) as well as polycultures of C. alliodora (POLY) planted with crops, pasture or other trees. Plot measurements included: tree height (HT), age (AGE), breast height diameter (DBH), height-to-crown (HToCR), and crown diameter (CD), site soil texture and pH. Understory measurements included the number of total plant species (SR) and aboveground biomass (UBIO). The HT of C. alliodora was related to AGE and DBH, but not to TPH. DBH was directly related to AGE and CD, and decreased with increasing TPH. The HToCR and volume/ha of C. alliodora were significantly associated with TPH, AGE and whether the plot was a MONO or POLY. The ratio of CD/DBH was related to AGE and with MONO or POLY, but not with TPH. Preliminary density management diagrams constructed from study data illustrate that for trees of a given age, volume is directly related to TPH. These results suggest that the yield of C. alliodora can be influenced via stand density management. In 1992, there was no significant difference in UBIO between MONO and POLY (79.75 kg ha^-1 and 54.27 kg ha^-1, respectively). The UBIO in MONO was significantly greater in 1996 than in 1992. In contrast, UBIO in POLY was significantly less in 1996 than in 1992. By 1996, the UBIO between MONO versus POLY was significantly different. From 1992 to 1996, SR in the MONO and POLY plantations decreased from 109 to 20. Total SR during early stand development of C. alliodora plantations was as high as secondary succession on similar sites in northern Costa Rica. It is not possible to maximize individual tree growth and stand growth of C. alliodora simultaneously. Optimal stand density will depend on site objectives for wood volume and understory production. Title: Stand development of Cordia alliodora (Boraginaceae), a neotropical secondary forest tree in northern Costa Rica (1992-1996) Author: Hummel, Susan Stevens Cordia alliodora is used for reforestation programs and farm income in northern Costa Rica. This study investigated: 1) responses of C. alliodora associated with stand density, or trees/ha (TPH), and 2) plant diversity and biomass in the understory of C. alliodora plantations. Three Nelder plots, 31 temporary plots and 6 plantations in northern Costa Rica were measured between 1992-1996. The plots included monocultures of C. alliodora (MONO) as well as polycultures of C. alliodora (POLY) planted with crops, pasture or other trees. Plot measurements included: tree height (HT), age (AGE), breast height diameter (DBH), height-to-crown (HToCR), and crown diameter (CD), site soil texture and pH. Understory measurements included the number of total plant species (SR) and aboveground biomass (UBIO). The HT of C. alliodora was related to AGE and DBH, but not to TPH. DBH was directly related to AGE and CD, and decreased with increasing TPH. The HToCR and volume/ha of C. alliodora were significantly associated with TPH, AGE and whether the plot was a MONO or POLY. The ratio of CD/DBH was related to AGE and with MONO or POLY, but not with TPH. Preliminary density management diagrams constructed from study data illustrate that for trees of a given age, volume is directly related to TPH. These results suggest that the yield of C. alliodora can be influenced via stand density management. In 1992, there was no significant difference in UBIO between MONO and POLY (79.75 kg ha^-1 and 54.27 kg ha^-1, respectively). The UBIO in MONO was significantly greater in 1996 than in 1992. In contrast, UBIO in POLY was significantly less in 1996 than in 1992. By 1996, the UBIO between MONO versus POLY was significantly different. From 1992 to 1996, SR in the MONO and POLY plantations decreased from 109 to 20. Total SR during early stand development of C. alliodora plantations was as high as secondary succession on similar sites in northern Costa Rica. It is not possible to maximize individual tree growth and stand growth of C. alliodora simultaneously. Optimal stand density will depend on site objectives for wood volume and understory production. Close