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• 2161. [Article] Cyclic triaxial testing of low- to moderate-plasticity silts

  This project report presents a laboratory investigation of the dynamic behavior of saturated alluvial silty soils from sites in Oregon and Washington. The focus of the study was to document the liquefaction ...

  Citation × Citation Citation Abstract Copy Title: Cyclic triaxial testing of low- to moderate-plasticity silts Author: Butler-Brown, Jason J. This project report presents a laboratory investigation of the dynamic behavior of saturated alluvial silty soils from sites in Oregon and Washington. The focus of the study was to document the liquefaction susceptibility, post cyclic strength, and volumetric strain behavior of the silt soils based on cyclic, undrained triaxial compression testing. A cyclic triaxial testing apparatus with computer control and data acquisition was assembled, calibrated, and used to perform undrained cyclic triaxial testing and post cyclic testing on undisturbed and reconstituted specimens. The results of this investigation are compared with the undrained cyclic triaxial testing data on silty soils published by others. The influence, of grain-size distribution, plasticity index, and overconsolidation ratio (OCR) on the dynamic behavior was identified. Several cyclic resistance curves were prepared that show the cyclic resistance for the silts for OCR values of 1 to 2.5. The cyclic resistance curves observed in the laboratory likely overestimate the in-situ cyclic resistance of the material due to sample disturbance during sampling, transport, and testing. It was observed that OCR has a significant influence on the cyclic resistance of silt soils. Cyclic resistance was observed to increase with increasing plasticity and percent passing the U.S. Standard Number 200 Sieve and percent finer than 2 μm. It was observed that excess pore pressure measurements recorded at the transducer for fine-grained soils subjected to rapid loading may not accurately represent the actual pore pressures of the soil. Therefore, it is proposed that strain criteria be used, rather than excess pore pressure generation, to define initial liquefaction for fine-grained soils. Post cyclic undrained strength test data shows that the silts are dilative under compressive loading in the triaxial apparatus. Peak strengths were not observed due to the dilative nature of the silty soil tested. Therefore, post cyclic undrained strengths were strain based. The strain based strengths were compared with relationships developed by Baziar and Dobry (1995) and Ishihara (1993) and were found to have a higher residual strength than the sandy soils. Unusually high S[subscript u]/p' ratios were also recorded for the silt soils. This observation highlights the need to obtain post-cyclic strength at a consistent strain. The post cyclic volumetric strain data was compared with the findings of Ishihara and Yoshimine (1992). Plots of volumetric strain versus maximum axial strain were created. These plots were then used to establish a relationship between post cyclic volumetric strain and the factor of safety against liquefaction. The volumetric strain behavior of the silt was observed to be very similar to sand at relative densities of 40 to 80 percent. Title: Cyclic triaxial testing of low- to moderate-plasticity silts Author: Butler-Brown, Jason J. This project report presents a laboratory investigation of the dynamic behavior of saturated alluvial silty soils from sites in Oregon and Washington. The focus of the study was to document the liquefaction susceptibility, post cyclic strength, and volumetric strain behavior of the silt soils based on cyclic, undrained triaxial compression testing. A cyclic triaxial testing apparatus with computer control and data acquisition was assembled, calibrated, and used to perform undrained cyclic triaxial testing and post cyclic testing on undisturbed and reconstituted specimens. The results of this investigation are compared with the undrained cyclic triaxial testing data on silty soils published by others. The influence, of grain-size distribution, plasticity index, and overconsolidation ratio (OCR) on the dynamic behavior was identified. Several cyclic resistance curves were prepared that show the cyclic resistance for the silts for OCR values of 1 to 2.5. The cyclic resistance curves observed in the laboratory likely overestimate the in-situ cyclic resistance of the material due to sample disturbance during sampling, transport, and testing. It was observed that OCR has a significant influence on the cyclic resistance of silt soils. Cyclic resistance was observed to increase with increasing plasticity and percent passing the U.S. Standard Number 200 Sieve and percent finer than 2 μm. It was observed that excess pore pressure measurements recorded at the transducer for fine-grained soils subjected to rapid loading may not accurately represent the actual pore pressures of the soil. Therefore, it is proposed that strain criteria be used, rather than excess pore pressure generation, to define initial liquefaction for fine-grained soils. Post cyclic undrained strength test data shows that the silts are dilative under compressive loading in the triaxial apparatus. Peak strengths were not observed due to the dilative nature of the silty soil tested. Therefore, post cyclic undrained strengths were strain based. The strain based strengths were compared with relationships developed by Baziar and Dobry (1995) and Ishihara (1993) and were found to have a higher residual strength than the sandy soils. Unusually high S[subscript u]/p' ratios were also recorded for the silt soils. This observation highlights the need to obtain post-cyclic strength at a consistent strain. The post cyclic volumetric strain data was compared with the findings of Ishihara and Yoshimine (1992). Plots of volumetric strain versus maximum axial strain were created. These plots were then used to establish a relationship between post cyclic volumetric strain and the factor of safety against liquefaction. The volumetric strain behavior of the silt was observed to be very similar to sand at relative densities of 40 to 80 percent. Close

• 2162. [Article] Will wetlands restoration plans today still be effective tomorrow? Evaluation of performance of potential wetlands for peak flow reduction in future climate scenarios in the Eagle Creek Watershed, IN

  Global climate change is expected to exaggerate the severity of floods and droughts and increase the frequency of extreme streamflow events in the Midwestern United States. Managing these projected impacts ...

  Citation × Citation Citation Abstract Copy Title: Will wetlands restoration plans today still be effective tomorrow? Evaluation of performance of potential wetlands for peak flow reduction in future climate scenarios in the Eagle Creek Watershed, IN Author: Walters, Kelli M. Global climate change is expected to exaggerate the severity of floods and droughts and increase the frequency of extreme streamflow events in the Midwestern United States. Managing these projected impacts poses a major challenge for water resources, conservation, and land use management. Wetlands have been considered as a conservation strategy and work to increase the capacity of watersheds by storing runoff upstream. The implementation of wetlands, especially in tile-drained agricultural watersheds, can reduce peak flows and help mitigate the anticipated impacts of climate change. The goal of this study was to evaluate the long-term performance of wetlands to reduce peak flows in future climate scenarios in the Eagle Creek Watershed in Indiana, as well as to establish a methodology to incorporate climate change into hydrological models to conduct better long-term land management studies and decisions. The Soil and Water Assessment Tool (SWAT) model was forced with bias corrected climate projections from the North American Regional Climate Change Assessment Program (NARCCAP) to evaluate the impacts of climate change on watershed hydrology and the ability of wetlands to reduce peak flows. Long-term monthly streamflow results predicted a slight increase in streamflow in the winter and a slight decrease in the summer from the past (1971-2000) to future (2041-2070) time periods. About half of the climate realizations produced an increase in the Q05 (5% exceedance flow) value and half a decrease, but all predictions agreed that high flow events will increase in frequency in the winter and decrease in the spring and summer. No-flow events, although found to be over-predicted by the hydrological model, showed an increase from the past to the future for all climate realizations. Results from the wetland analysis showed that if all potential wetlands identified in a previous study are installed in the watershed, maximum peak flow reductions of around 20-50 m³/s for the past and future, as well as decreased frequency of extreme events, can be seen. Wetlands proved to be a robust solution for peak flow reduction, producing consistent reductions across all climate projections for both the past and future time periods. Title: Will wetlands restoration plans today still be effective tomorrow? Evaluation of performance of potential wetlands for peak flow reduction in future climate scenarios in the Eagle Creek Watershed, IN Author: Walters, Kelli M. Global climate change is expected to exaggerate the severity of floods and droughts and increase the frequency of extreme streamflow events in the Midwestern United States. Managing these projected impacts poses a major challenge for water resources, conservation, and land use management. Wetlands have been considered as a conservation strategy and work to increase the capacity of watersheds by storing runoff upstream. The implementation of wetlands, especially in tile-drained agricultural watersheds, can reduce peak flows and help mitigate the anticipated impacts of climate change. The goal of this study was to evaluate the long-term performance of wetlands to reduce peak flows in future climate scenarios in the Eagle Creek Watershed in Indiana, as well as to establish a methodology to incorporate climate change into hydrological models to conduct better long-term land management studies and decisions. The Soil and Water Assessment Tool (SWAT) model was forced with bias corrected climate projections from the North American Regional Climate Change Assessment Program (NARCCAP) to evaluate the impacts of climate change on watershed hydrology and the ability of wetlands to reduce peak flows. Long-term monthly streamflow results predicted a slight increase in streamflow in the winter and a slight decrease in the summer from the past (1971-2000) to future (2041-2070) time periods. About half of the climate realizations produced an increase in the Q05 (5% exceedance flow) value and half a decrease, but all predictions agreed that high flow events will increase in frequency in the winter and decrease in the spring and summer. No-flow events, although found to be over-predicted by the hydrological model, showed an increase from the past to the future for all climate realizations. Results from the wetland analysis showed that if all potential wetlands identified in a previous study are installed in the watershed, maximum peak flow reductions of around 20-50 m³/s for the past and future, as well as decreased frequency of extreme events, can be seen. Wetlands proved to be a robust solution for peak flow reduction, producing consistent reductions across all climate projections for both the past and future time periods. Close

• 2163. [Article] Student performance in lower division collegiate general biology programs in selected community colleges and four-year institutions in Oregon

  It was the intent of this investigation to compare the performance of community college students to four-year institutional students, both of whom were enrolled in a college general biology program (GS ...

  Citation × Citation Citation Abstract Copy Title: Student performance in lower division collegiate general biology programs in selected community colleges and four-year institutions in Oregon Author: Tolman, Richard Robins It was the intent of this investigation to compare the performance of community college students to four-year institutional students, both of whom were enrolled in a college general biology program (GS 101, 102, 103) during the 1967-68 academic year. During the week of May 27, 1968 measurements were taken of student performance in the two types of institutions in terms of the following important objectives of biology teaching: critical thinking; knowledge of facts and principles; comprehension; application; and a combination of analysis, synthesis, and evaluation. The criterion instruments used to measure these objectives were the Cornell Critical Thinking Test, Form Z, developed by R. Ennis and J. Millman, and a biology test developed by the researcher. The population for this investigation consisted of full-time students enrolled in a general biology course at either of three community colleges or two four-year institutions in Oregon. A total of 261 students were in the community college sample and 465 students were in the four-year institution sample. Findings The findings from this research were based on results of a Gauss-Markoff Setup for Multiple Measurements (analysis of dispersion) statistical design. The effects due to a difference in high school G. P. A. and sex among students in the samples were removed from the mean scores used in the statistical analysis. Resultant F values were tested at the 1 percent level. 1. There was a significant statistical difference among community colleges in terms of the behavioral objectives of knowledge of facts and principles and a combination of analysis, synthesis, and evaluation. 2. There was a significant statistical difference among four- year institutions in terms of all behavioral objectives of the biology criterion instrument. It was concluded that one of the major factors causing the difference among the four-year institutions was one additional hour per week spent in a discussion session with a biology instructor at university # 1. 3. Although significant statistical differences existed among community colleges and among four-year institutions, there was still a significant difference between community colleges and four-year institutions in terms of critical thinking ability and the behavioral objective of knowledge of facts and principles of biology. It was concluded that four-year institutional students received a superior educational experience to community college students in terms of the development of critical thinking ability. It was also concluded that a major cause of the significant statistical difference between community colleges and four-year institutions in terms of the behavioral objective of knowledge of facts and principles of biology was an overemphasis on memorization and factual recall by community college instructors. Title: Student performance in lower division collegiate general biology programs in selected community colleges and four-year institutions in Oregon Author: Tolman, Richard Robins It was the intent of this investigation to compare the performance of community college students to four-year institutional students, both of whom were enrolled in a college general biology program (GS 101, 102, 103) during the 1967-68 academic year. During the week of May 27, 1968 measurements were taken of student performance in the two types of institutions in terms of the following important objectives of biology teaching: critical thinking; knowledge of facts and principles; comprehension; application; and a combination of analysis, synthesis, and evaluation. The criterion instruments used to measure these objectives were the Cornell Critical Thinking Test, Form Z, developed by R. Ennis and J. Millman, and a biology test developed by the researcher. The population for this investigation consisted of full-time students enrolled in a general biology course at either of three community colleges or two four-year institutions in Oregon. A total of 261 students were in the community college sample and 465 students were in the four-year institution sample. Findings The findings from this research were based on results of a Gauss-Markoff Setup for Multiple Measurements (analysis of dispersion) statistical design. The effects due to a difference in high school G. P. A. and sex among students in the samples were removed from the mean scores used in the statistical analysis. Resultant F values were tested at the 1 percent level. 1. There was a significant statistical difference among community colleges in terms of the behavioral objectives of knowledge of facts and principles and a combination of analysis, synthesis, and evaluation. 2. There was a significant statistical difference among four- year institutions in terms of all behavioral objectives of the biology criterion instrument. It was concluded that one of the major factors causing the difference among the four-year institutions was one additional hour per week spent in a discussion session with a biology instructor at university # 1. 3. Although significant statistical differences existed among community colleges and among four-year institutions, there was still a significant difference between community colleges and four-year institutions in terms of critical thinking ability and the behavioral objective of knowledge of facts and principles of biology. It was concluded that four-year institutional students received a superior educational experience to community college students in terms of the development of critical thinking ability. It was also concluded that a major cause of the significant statistical difference between community colleges and four-year institutions in terms of the behavioral objective of knowledge of facts and principles of biology was an overemphasis on memorization and factual recall by community college instructors. Close

• 2164. [Article] Studies on the toxicity of the carcinostatic compound 1, 3-bis (2-chloroethyl)-1-nitrosourea

  Investigations were undertaken to characterize the toxicity in animals treated with 1, 3-Bis(2-chloroethyl)-1-nitrosourea (BCNU). Primary experimental interest in this compound had centered around its ...

  Citation × Citation Citation Abstract Copy Title: Studies on the toxicity of the carcinostatic compound 1, 3-bis (2-chloroethyl)-1-nitrosourea Author: Thompson, George Rex Investigations were undertaken to characterize the toxicity in animals treated with 1, 3-Bis(2-chloroethyl)-1-nitrosourea (BCNU). Primary experimental interest in this compound had centered around its antineoplastic activity; however, clinical application of the compound resulted in the appearance of delayed toxicity symptoms. A critical evaluation of the toxicity associated with BCNU has not been reported, therefore, these studies were undertaken to fill this need. That BCNU produced a latent toxicity was verified in acute lethality studies. No deaths occurred prior to five days post treatment even with doses three to five times the median lethal dose (LD50). The LD50, determined by the administration of graded, single oral doses of BCNU to rats, was found to be 30 mg/kg when the observation time was 30 days. If the cut-off time was extended to 70 days, 30 mg/kg resulted in mortality of all treated animals. Furthermore, if the cut-off time was set at 90-100 days, a single dose of 20 mg/kg killed all treated animals. Similar mortality patterns were observed for another nitrosourea derivative, 1-(2-chloroethyl) -3-cyclohexyl-l-nitrosourea (CCNU), but this congener was only half as potent as BCNU on either a weight or molar basis. Decreased body weight of the BCNU treated animals was one of the most conspicuous features of the toxicity. The magnitude of this effect was dose related and could be attributed to alterations in several metabolic systems. Parallel reductions of plasma volume and body weight suggested that the decreased animal weight reflected loss of body water. Decreased food consumption also contributed to weight losses. In addition, increased blood urea nitrogen levels and diminished weights of liver, kidney and brain suggested that an increase of catabolism may have complemented the body weight losses. A prolonged and progressive bimodal hepatotoxicity was revealed by a series of standard hepatic function techniques following BCNU administration to rats. By one week post treatment, all doses of BCNU resulted in prolonged pentobarbital hypnosis and enhanced bromsulfalein (BSP) retention. Enzyme induction with phenobarbital significantly decreased the prolongation of narcosis. Elevations of serum bilirubin (SBr) appeared later, being delayed by as much as 63 days at the lowest dose. SBr was direct-reacting at early stages but later shifted to indirect reacting coincidental with a reduction of BSP retention. Histopathological evaluation revealed early pericholangitis and necrosis of bile ductules. This pattern progressed to one of focal necrosis of the hepatocytes, biliary cirrhosis and proliferation of biliary epithelium. Hematological examination disclosed an early leukopenia with a later decrease in hematocrit and erythrocyte levels. Hemoglobin levels, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, as well as mean corpuscular volume did not deviate statistically from control levels. A diminished albumin-globulin ratio was also detected. Plasma volume and total blood volume were severely decreased at extended times. When expressed as per cent of body weight however, both plasma and blood volume did not deviate from control values. This was consistent with the hypothesis that the lower body weights of treated animals reflected losses of total body water. High doses of BCNU were also found to decrease intestinal and blood levels of serotonin. Brain levels of serotonin were significantly elevated. These actions of BCNU may make the drug especially useful as an investigative tool for evaluating the biological importance of serotonin. In addition, some of the signs of BCNU toxicity may be explained by the serotonin alterations. The ability of BCNU to produce a severe and delayed toxicity with a wide diversity of effects was verified in these studies. The pattern of mortality induced by BCNU administration appeared to result from a multiplicity of factors rather than a single toxic manifestation. The mechanism(s) by which the physiological systems were compromised must await further investigations. Title: Studies on the toxicity of the carcinostatic compound 1, 3-bis (2-chloroethyl)-1-nitrosourea Author: Thompson, George Rex Investigations were undertaken to characterize the toxicity in animals treated with 1, 3-Bis(2-chloroethyl)-1-nitrosourea (BCNU). Primary experimental interest in this compound had centered around its antineoplastic activity; however, clinical application of the compound resulted in the appearance of delayed toxicity symptoms. A critical evaluation of the toxicity associated with BCNU has not been reported, therefore, these studies were undertaken to fill this need. That BCNU produced a latent toxicity was verified in acute lethality studies. No deaths occurred prior to five days post treatment even with doses three to five times the median lethal dose (LD50). The LD50, determined by the administration of graded, single oral doses of BCNU to rats, was found to be 30 mg/kg when the observation time was 30 days. If the cut-off time was extended to 70 days, 30 mg/kg resulted in mortality of all treated animals. Furthermore, if the cut-off time was set at 90-100 days, a single dose of 20 mg/kg killed all treated animals. Similar mortality patterns were observed for another nitrosourea derivative, 1-(2-chloroethyl) -3-cyclohexyl-l-nitrosourea (CCNU), but this congener was only half as potent as BCNU on either a weight or molar basis. Decreased body weight of the BCNU treated animals was one of the most conspicuous features of the toxicity. The magnitude of this effect was dose related and could be attributed to alterations in several metabolic systems. Parallel reductions of plasma volume and body weight suggested that the decreased animal weight reflected loss of body water. Decreased food consumption also contributed to weight losses. In addition, increased blood urea nitrogen levels and diminished weights of liver, kidney and brain suggested that an increase of catabolism may have complemented the body weight losses. A prolonged and progressive bimodal hepatotoxicity was revealed by a series of standard hepatic function techniques following BCNU administration to rats. By one week post treatment, all doses of BCNU resulted in prolonged pentobarbital hypnosis and enhanced bromsulfalein (BSP) retention. Enzyme induction with phenobarbital significantly decreased the prolongation of narcosis. Elevations of serum bilirubin (SBr) appeared later, being delayed by as much as 63 days at the lowest dose. SBr was direct-reacting at early stages but later shifted to indirect reacting coincidental with a reduction of BSP retention. Histopathological evaluation revealed early pericholangitis and necrosis of bile ductules. This pattern progressed to one of focal necrosis of the hepatocytes, biliary cirrhosis and proliferation of biliary epithelium. Hematological examination disclosed an early leukopenia with a later decrease in hematocrit and erythrocyte levels. Hemoglobin levels, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, as well as mean corpuscular volume did not deviate statistically from control levels. A diminished albumin-globulin ratio was also detected. Plasma volume and total blood volume were severely decreased at extended times. When expressed as per cent of body weight however, both plasma and blood volume did not deviate from control values. This was consistent with the hypothesis that the lower body weights of treated animals reflected losses of total body water. High doses of BCNU were also found to decrease intestinal and blood levels of serotonin. Brain levels of serotonin were significantly elevated. These actions of BCNU may make the drug especially useful as an investigative tool for evaluating the biological importance of serotonin. In addition, some of the signs of BCNU toxicity may be explained by the serotonin alterations. The ability of BCNU to produce a severe and delayed toxicity with a wide diversity of effects was verified in these studies. The pattern of mortality induced by BCNU administration appeared to result from a multiplicity of factors rather than a single toxic manifestation. The mechanism(s) by which the physiological systems were compromised must await further investigations. Close

• 2165. [Article] Issues experienced by community college STEM faculty implementing and using pedagogies of engagement

  The purpose of this study was to explore the issues involved with implementing and using pedagogies of engagement in community college STEM courses. The rationale for this study was based on current and ...

  Citation × Citation Citation Abstract Copy Title: Issues experienced by community college STEM faculty implementing and using pedagogies of engagement Author: Thatcher, Valory Rae Anna The purpose of this study was to explore the issues involved with implementing and using pedagogies of engagement in community college STEM courses. The rationale for this study was based on current and emerging STEM education policy directives calling for an updated approach to teaching undergraduates, focused on student engagement, and also the need to include the perspectives of community college faculty in guiding the refinement of these policies. Pedagogies of engagement are classroom techniques intended to stimulate deeper and more student-centered learning experiences and include such activities as calibrated peer review, cooperative learning, interactive lectures, case-based studies, and peer-led learning. Numerous studies have indicated that pedagogy intending to better engage students can improve learning as well as retain and even recruit students into STEM fields. Therefore, engagement has been a central theme in recent education policy. Given the relatively-new policy encouraging the use of pedagogies of engagement in undergraduate STEM courses, research that contributes to this topic is significant, especially in the community college setting, a focus that is rarely highlighted in the literature. This study was designed to contribute to the growing body of research about how pedagogies of engagement can improve community college STEM programs by investigating issues that full-time faculty experience when implementing and using these pedagogical strategies. This study was guided by the following foundational questions: (1) What are the issues involving pedagogies of engagement in community college STEM programs? (2) How can the identified issues be resolved? (3) What strategies can be used for implementing and using pedagogies of engagement? This study employed a qualitative research approach focusing on six individual community college full-time faculty members who were experienced with these instructional styles. These individuals were recruited via a preliminary screening survey that determined their experience with the techniques and willingness to be interviewed. The data gathered in this study consisted of inperson interviews, analysis of supportive documentation provided by or referred to by the participants, and participant feedback of the results. The issues experienced by full-time community college STEM faculty when implementing and using pedagogies of engagement were broadly organized into the following themes: student issues, faculty issues, and external issues. Student issues involved student resistance and the perception of engaged pedagogy being of lesser value than traditional lecture-based instructional approaches. Faculty issues included skepticism of the efficacy of the pedagogy, the need for curriculum planning time, cost of facility and equipment upgrades, and the lack of assessment tools to measure student engagement. External issues included insufficient access to professional development opportunities with an engagement focus and also the need for faculty evaluation systems with student engagement as a key outcome. The study findings revealed that those issues could be resolved through collaborative team problem-solving approaches and through participation in high-quality professional development programs. Finally, in regard to the final research question involving strategies for implementing and using pedagogies of engagement, questions for practice were developed that community college educators might consider when implementing these instructional strategies. Title: Issues experienced by community college STEM faculty implementing and using pedagogies of engagement Author: Thatcher, Valory Rae Anna The purpose of this study was to explore the issues involved with implementing and using pedagogies of engagement in community college STEM courses. The rationale for this study was based on current and emerging STEM education policy directives calling for an updated approach to teaching undergraduates, focused on student engagement, and also the need to include the perspectives of community college faculty in guiding the refinement of these policies. Pedagogies of engagement are classroom techniques intended to stimulate deeper and more student-centered learning experiences and include such activities as calibrated peer review, cooperative learning, interactive lectures, case-based studies, and peer-led learning. Numerous studies have indicated that pedagogy intending to better engage students can improve learning as well as retain and even recruit students into STEM fields. Therefore, engagement has been a central theme in recent education policy. Given the relatively-new policy encouraging the use of pedagogies of engagement in undergraduate STEM courses, research that contributes to this topic is significant, especially in the community college setting, a focus that is rarely highlighted in the literature. This study was designed to contribute to the growing body of research about how pedagogies of engagement can improve community college STEM programs by investigating issues that full-time faculty experience when implementing and using these pedagogical strategies. This study was guided by the following foundational questions: (1) What are the issues involving pedagogies of engagement in community college STEM programs? (2) How can the identified issues be resolved? (3) What strategies can be used for implementing and using pedagogies of engagement? This study employed a qualitative research approach focusing on six individual community college full-time faculty members who were experienced with these instructional styles. These individuals were recruited via a preliminary screening survey that determined their experience with the techniques and willingness to be interviewed. The data gathered in this study consisted of inperson interviews, analysis of supportive documentation provided by or referred to by the participants, and participant feedback of the results. The issues experienced by full-time community college STEM faculty when implementing and using pedagogies of engagement were broadly organized into the following themes: student issues, faculty issues, and external issues. Student issues involved student resistance and the perception of engaged pedagogy being of lesser value than traditional lecture-based instructional approaches. Faculty issues included skepticism of the efficacy of the pedagogy, the need for curriculum planning time, cost of facility and equipment upgrades, and the lack of assessment tools to measure student engagement. External issues included insufficient access to professional development opportunities with an engagement focus and also the need for faculty evaluation systems with student engagement as a key outcome. The study findings revealed that those issues could be resolved through collaborative team problem-solving approaches and through participation in high-quality professional development programs. Finally, in regard to the final research question involving strategies for implementing and using pedagogies of engagement, questions for practice were developed that community college educators might consider when implementing these instructional strategies. Close

• 2166. [Article] Traits relevant to creativity present in four year old nursery school children

  The purpose of this study was to determine if personality traits relevant to creativity in adults are measurable in four year old nursery school children. Instruments and scoring techniques were developed ...

  Citation × Citation Citation Abstract Copy Title: Traits relevant to creativity present in four year old nursery school children Author: Cooper, Beverly McKnight The purpose of this study was to determine if personality traits relevant to creativity in adults are measurable in four year old nursery school children. Instruments and scoring techniques were developed to measure six specific traits. These traits are the intellectual aptitude abilities of figural fluency, elaboration, originality and penetration and the non aptitude traits of curiosity and autonomy. Subjects of the study were 28 children in attendance at Oregon State University nursery schools who were four years zero months to and including four years eleven months at the time of testing. The four intellectual aptitude traits were measured by two tasks which are independent measures of the subjects' individual response to a creative situation. A revision of the Minnesota Bureau of Research's Incomplete Figures Task and the Lowenfeld Kaleidoblocs were used with scoring procedures developed specifically for this research. A curiosity instrument patterned after one designed by Starkweather was developed to measure interest in the unknown. Autonomy was rated by the subjects' nursery school teachers on a scale designed after separate instruments used by Joel and Heather. The results were considered in terms of the distribution of raw scores to determine if the tests discriminated in the measurement of the abilities of the subjects. Correlation coefficients were calculated to determine interrelationships between the traits. As the scores for several traits were distributed over a narrow range interpretation was limited, therefore, the analysis of the correlations was in terms of clusters of scores rather than independent correlations. Finally the subjects were ranked according to their individual creative ability. Six highly creative and five noncreative subjects were isolated and a comparison was made between the two groups. It was concluded that a definite value of both the Incomplete Figures and Kaleidobloc Tasks was their initial appeal and ability to maintain the interest of the subjects. The distribution of scores of the tasks was indication that the two instruments discriminate in the measurement of the abilities of the subjects. A significant correlation was found between the Incomplete Figures and Kaleidobloc Tasks which suggests that the two instruments measure the same traits. There was no correlation between curiosity and the creativity traits implying either that there is no relationship between an interest in the unknown and/or creativity at four years of age in a similar population, or that the instrument is not a reliable and/or valid instrument of measurement. Autonomy was not found to be correlated with the traits of creativity. As the scale appeared to be a valid measure of autonomy and the distribution of scores suggested some reliability it was hypothesized that autonomy is not relevant to creativity at four years of age. The rationale is that the concept of autonomy includes not only independence but sociability, conformity, and intolerance to disorder. The conclusion to be drawn from this study is that two instruments were developed which appear useful as measurement of some intellectual aptitude traits of creativity in preschool children. Title: Traits relevant to creativity present in four year old nursery school children Author: Cooper, Beverly McKnight The purpose of this study was to determine if personality traits relevant to creativity in adults are measurable in four year old nursery school children. Instruments and scoring techniques were developed to measure six specific traits. These traits are the intellectual aptitude abilities of figural fluency, elaboration, originality and penetration and the non aptitude traits of curiosity and autonomy. Subjects of the study were 28 children in attendance at Oregon State University nursery schools who were four years zero months to and including four years eleven months at the time of testing. The four intellectual aptitude traits were measured by two tasks which are independent measures of the subjects' individual response to a creative situation. A revision of the Minnesota Bureau of Research's Incomplete Figures Task and the Lowenfeld Kaleidoblocs were used with scoring procedures developed specifically for this research. A curiosity instrument patterned after one designed by Starkweather was developed to measure interest in the unknown. Autonomy was rated by the subjects' nursery school teachers on a scale designed after separate instruments used by Joel and Heather. The results were considered in terms of the distribution of raw scores to determine if the tests discriminated in the measurement of the abilities of the subjects. Correlation coefficients were calculated to determine interrelationships between the traits. As the scores for several traits were distributed over a narrow range interpretation was limited, therefore, the analysis of the correlations was in terms of clusters of scores rather than independent correlations. Finally the subjects were ranked according to their individual creative ability. Six highly creative and five noncreative subjects were isolated and a comparison was made between the two groups. It was concluded that a definite value of both the Incomplete Figures and Kaleidobloc Tasks was their initial appeal and ability to maintain the interest of the subjects. The distribution of scores of the tasks was indication that the two instruments discriminate in the measurement of the abilities of the subjects. A significant correlation was found between the Incomplete Figures and Kaleidobloc Tasks which suggests that the two instruments measure the same traits. There was no correlation between curiosity and the creativity traits implying either that there is no relationship between an interest in the unknown and/or creativity at four years of age in a similar population, or that the instrument is not a reliable and/or valid instrument of measurement. Autonomy was not found to be correlated with the traits of creativity. As the scale appeared to be a valid measure of autonomy and the distribution of scores suggested some reliability it was hypothesized that autonomy is not relevant to creativity at four years of age. The rationale is that the concept of autonomy includes not only independence but sociability, conformity, and intolerance to disorder. The conclusion to be drawn from this study is that two instruments were developed which appear useful as measurement of some intellectual aptitude traits of creativity in preschool children. Close

• 2167. [Article] Soluble carbon and respiration of forest humus

  Humus is one of the important factors controlling the soil formation process. The nutrients released from it during the decomposition process also affect the growth and reproduction of the forest. The ...

  Citation × Citation Citation Abstract Copy Title: Soluble carbon and respiration of forest humus Author: Hu, Lily Jho-yuan Humus is one of the important factors controlling the soil formation process. The nutrients released from it during the decomposition process also affect the growth and reproduction of the forest. The type of humus formed is influenced by the nature of the forest litter and the environment in which it is decomposed. The whole complex of processes by which plant residues are transformed and finally converted into humus is the result of the combined activity of associations of microbes exhibiting diverse biochemical functions. The respiratory activity in the forest floor decreases with progressive stages of decomposition and humification. This reflects the chemical composition and availability of the remaining carbon compounds as energy source material. It appeared that the content of total soluble carbon might serve as an index of the stage of decomposition and humification. As a mild oxidizing reagent, potassium persulfate oxidizes only the water soluble materials in the temperature range of 70°C to 75°C. A water extraction-potassium persulfate oxidation technique was used for the estimation of total soluble carbon content of forest floor materials. Extraction time and the efficiency of the persulfate oxidation of the extract were also investigated. Continuous aeration and electrolytic respirometer techniques were used for the respiration study and for comparison with the persulfate oxidation technique. A variety of representative forest floor materials from different forest types in Eastern North America and the Coast Range of Oregon were studied both for respiratory activity and for water soluble carbon content. A highly significant positive correlation was found between levels of water soluble carbon and CO₂ evolution in these samples. In the areas sampled in the eastern United States and Canada, a majority of the well humified layers (H) gave respiratory carbon/soluble carbon ratios of 1. Most of the less humified samples showed ratios near 1.4. Materials from Douglas-fir forests having low soluble carbon levels had considerably greater respiratory carbon/soluble carbon ratios than the low soluble carbon materials from eastern forests. The advantages of the persulfate oxidation method over the respiration method are that it is less time consuming, few materials are required and better control can be exercised. Since the water soluble carbon as determined by the persulfate oxidation test may be expressed in terms of respiration, where good correlations are established, it appears that either the soluble carbon value itself or the correlated respiratory activity may be used as an indicator of the stage of humification. Thus a much more rapid, less tedious means of evaluating the status of forest floor materials is available. Title: Soluble carbon and respiration of forest humus Author: Hu, Lily Jho-yuan Humus is one of the important factors controlling the soil formation process. The nutrients released from it during the decomposition process also affect the growth and reproduction of the forest. The type of humus formed is influenced by the nature of the forest litter and the environment in which it is decomposed. The whole complex of processes by which plant residues are transformed and finally converted into humus is the result of the combined activity of associations of microbes exhibiting diverse biochemical functions. The respiratory activity in the forest floor decreases with progressive stages of decomposition and humification. This reflects the chemical composition and availability of the remaining carbon compounds as energy source material. It appeared that the content of total soluble carbon might serve as an index of the stage of decomposition and humification. As a mild oxidizing reagent, potassium persulfate oxidizes only the water soluble materials in the temperature range of 70°C to 75°C. A water extraction-potassium persulfate oxidation technique was used for the estimation of total soluble carbon content of forest floor materials. Extraction time and the efficiency of the persulfate oxidation of the extract were also investigated. Continuous aeration and electrolytic respirometer techniques were used for the respiration study and for comparison with the persulfate oxidation technique. A variety of representative forest floor materials from different forest types in Eastern North America and the Coast Range of Oregon were studied both for respiratory activity and for water soluble carbon content. A highly significant positive correlation was found between levels of water soluble carbon and CO₂ evolution in these samples. In the areas sampled in the eastern United States and Canada, a majority of the well humified layers (H) gave respiratory carbon/soluble carbon ratios of 1. Most of the less humified samples showed ratios near 1.4. Materials from Douglas-fir forests having low soluble carbon levels had considerably greater respiratory carbon/soluble carbon ratios than the low soluble carbon materials from eastern forests. The advantages of the persulfate oxidation method over the respiration method are that it is less time consuming, few materials are required and better control can be exercised. Since the water soluble carbon as determined by the persulfate oxidation test may be expressed in terms of respiration, where good correlations are established, it appears that either the soluble carbon value itself or the correlated respiratory activity may be used as an indicator of the stage of humification. Thus a much more rapid, less tedious means of evaluating the status of forest floor materials is available. Close

• 2168. [Article] The effects of forest fuel reduction on fire severity and long-term carbon storage

  Two forest management objectives being debated in the context of federally managed landscapes in the US Pacific Northwest involve a perceived trade-off between fire restoration and C sequestration. The ...

  Citation × Citation Citation Abstract Copy Title: The effects of forest fuel reduction on fire severity and long-term carbon storage Author: Mitchell, Stephen Richard Two forest management objectives being debated in the context of federally managed landscapes in the US Pacific Northwest involve a perceived trade-off between fire restoration and C sequestration. The former strategy would reduce fuel (and therefore C) that has accumulated through a century of fire suppression and exclusion that has led to extreme fire risk in some areas. The latter strategy would manage forests for enhanced C sequestration as a method of reducing atmospheric CO2 and associated threats from global climate change. We explored the tradeoff between these strategies by modeling their effects at both the stand and landscape-scale. We began with an assessment of the extent to which uncertainties in model parameter values, model structure, and field measurements can influence model performance. We adapted the generalized likelihood uncertainty estimation (GLUE) methodology for Biome-BGC, a widely used terrestrial ecosystem model. We found that the phenomenon of parameter equifinality exerted significant control on model performance, but that issues with model structure in the Biome-BGC model may present an even greater obstacle to model accuracy. We then examined the effects of fuel reduction on fire severity and the resulting long-term stand-level C storage by utilizing the STANDCARB model for three Pacific Northwest ecosystems: the east Cascades Ponderosa Pine forests, the west Cascades Western hemlock–Douglas fir forests, and the Coast Range Western hemlock– Sitka spruce forests. Finally, we then tested the extent to which various landscape-level fuel reduction treatments, when applied at various annual treatment areas, altered pyrogenic C emissions and long-term C storage in the east Cascades Ponderosa pine ecosystems. For this we employed the LANDCARB model, which models forests throughout a landscape on a stand-by-stand basis. Results from both the stand and landscape-level modeling indicate that, for fuel reduction treatments to be effective in reducing wildfire severity, they must be applied at higher frequencies and over larger areas than they are currently. Furthermore, fuel reduction treatments almost always reduce stand and landscape-level C storage, since reducing the fraction by which C is lost in a wildfire requires the removal of a much greater amount of C, since most of the C stored in forest biomass (stem wood, branches, coarse woody debris) remains unconsumed even by high-severity wildfires. Title: The effects of forest fuel reduction on fire severity and long-term carbon storage Author: Mitchell, Stephen Richard Two forest management objectives being debated in the context of federally managed landscapes in the US Pacific Northwest involve a perceived trade-off between fire restoration and C sequestration. The former strategy would reduce fuel (and therefore C) that has accumulated through a century of fire suppression and exclusion that has led to extreme fire risk in some areas. The latter strategy would manage forests for enhanced C sequestration as a method of reducing atmospheric CO2 and associated threats from global climate change. We explored the tradeoff between these strategies by modeling their effects at both the stand and landscape-scale. We began with an assessment of the extent to which uncertainties in model parameter values, model structure, and field measurements can influence model performance. We adapted the generalized likelihood uncertainty estimation (GLUE) methodology for Biome-BGC, a widely used terrestrial ecosystem model. We found that the phenomenon of parameter equifinality exerted significant control on model performance, but that issues with model structure in the Biome-BGC model may present an even greater obstacle to model accuracy. We then examined the effects of fuel reduction on fire severity and the resulting long-term stand-level C storage by utilizing the STANDCARB model for three Pacific Northwest ecosystems: the east Cascades Ponderosa Pine forests, the west Cascades Western hemlock–Douglas fir forests, and the Coast Range Western hemlock– Sitka spruce forests. Finally, we then tested the extent to which various landscape-level fuel reduction treatments, when applied at various annual treatment areas, altered pyrogenic C emissions and long-term C storage in the east Cascades Ponderosa pine ecosystems. For this we employed the LANDCARB model, which models forests throughout a landscape on a stand-by-stand basis. Results from both the stand and landscape-level modeling indicate that, for fuel reduction treatments to be effective in reducing wildfire severity, they must be applied at higher frequencies and over larger areas than they are currently. Furthermore, fuel reduction treatments almost always reduce stand and landscape-level C storage, since reducing the fraction by which C is lost in a wildfire requires the removal of a much greater amount of C, since most of the C stored in forest biomass (stem wood, branches, coarse woody debris) remains unconsumed even by high-severity wildfires. Close

• 2169. [Article] Ecology of curlleaf mountain-mahogany (Cercocarpus ledifolius Nutt.) in Eastern Oregon and adjacent areas

  Cercocarpus ledifolius (curlleaf mountain- mahogany), a small, hardwood evergreen tree, was studied to provide information on germination and initial seedling growth characteristics, and the species' relationship ...

  Citation × Citation Citation Abstract Copy Title: Ecology of curlleaf mountain-mahogany (Cercocarpus ledifolius Nutt.) in Eastern Oregon and adjacent areas Author: Dealy, J. Edward Cercocarpus ledifolius (curlleaf mountain- mahogany), a small, hardwood evergreen tree, was studied to provide information on germination and initial seedling growth characteristics, and the species' relationship to its environment.and associated vegetation. Exceptional germination for this species resulted from both a wet cold treatment at 4°C for 170 days (88 percent), and a 15-minute soak in a 30 percent solution of H202 (64 percent). Total and partial embryo excision indicated two possible deterrents to germination: mechanical impedance by the seed coat or a gas diffusion block by the membrane surrounding the embryo. The latter was concluded to be the most likely deterrent. Planting techniques must provide for seed coat deterioration by fall seeding (which allows moist winter conditions to do this) or by a brief, strong chemical treatment before spring planting. A pronounced specialization was demonstrated for rapid root growth in relation to top growth of seedlings for at least 120 days following germination. Under optimum laboratory conditions, the six most vigorous seedlings extended roots an average 1. 13 m in 120 days, but developed only 4 cm2 of leaf area and 2. 35 cm of shoot height, indicating a high potential for re-establishment of natural stands after decimation by fire or logging, or in the face of grass and shrub competition. Seedling stem diameter immediately above the root crown was an indicator of root vigor. Seedlings with the largest diameter stems were deepest rooted. Relationships among Cercocarpus ledifolius ecosystems were examined and 12 habitat types with their attendant plant associations, phases, and successional stages were delineated. Associations and their phases occurred due to topo.edaphic influences. No serious competition between C. ledifolius and other tree species existed in associations described. Where conifers occurred they were uncommon and not expanding their territory. Graminoids were the most predominant understory group in all associations based on dominance and constancy, with south slope associations generally having higher values than those on north slopes. Soil development was weak with no significant differences in solum development noted between exposures. However, percent surface stone on southerly exposures was twice that on the northerly, and percent buried stone volume in the solum was almost one-third greater on southerly exposures. The survival of C. ledifolius and the communities in which it was dominant were dependent on fire resistant rocky sites. Trees in these niches were larger and older than those on nearby non rocky sites and provided an available seed source in case fire decimated adjacent stands. Title: Ecology of curlleaf mountain-mahogany (Cercocarpus ledifolius Nutt.) in Eastern Oregon and adjacent areas Author: Dealy, J. Edward Cercocarpus ledifolius (curlleaf mountain- mahogany), a small, hardwood evergreen tree, was studied to provide information on germination and initial seedling growth characteristics, and the species' relationship to its environment.and associated vegetation. Exceptional germination for this species resulted from both a wet cold treatment at 4°C for 170 days (88 percent), and a 15-minute soak in a 30 percent solution of H202 (64 percent). Total and partial embryo excision indicated two possible deterrents to germination: mechanical impedance by the seed coat or a gas diffusion block by the membrane surrounding the embryo. The latter was concluded to be the most likely deterrent. Planting techniques must provide for seed coat deterioration by fall seeding (which allows moist winter conditions to do this) or by a brief, strong chemical treatment before spring planting. A pronounced specialization was demonstrated for rapid root growth in relation to top growth of seedlings for at least 120 days following germination. Under optimum laboratory conditions, the six most vigorous seedlings extended roots an average 1. 13 m in 120 days, but developed only 4 cm2 of leaf area and 2. 35 cm of shoot height, indicating a high potential for re-establishment of natural stands after decimation by fire or logging, or in the face of grass and shrub competition. Seedling stem diameter immediately above the root crown was an indicator of root vigor. Seedlings with the largest diameter stems were deepest rooted. Relationships among Cercocarpus ledifolius ecosystems were examined and 12 habitat types with their attendant plant associations, phases, and successional stages were delineated. Associations and their phases occurred due to topo.edaphic influences. No serious competition between C. ledifolius and other tree species existed in associations described. Where conifers occurred they were uncommon and not expanding their territory. Graminoids were the most predominant understory group in all associations based on dominance and constancy, with south slope associations generally having higher values than those on north slopes. Soil development was weak with no significant differences in solum development noted between exposures. However, percent surface stone on southerly exposures was twice that on the northerly, and percent buried stone volume in the solum was almost one-third greater on southerly exposures. The survival of C. ledifolius and the communities in which it was dominant were dependent on fire resistant rocky sites. Trees in these niches were larger and older than those on nearby non rocky sites and provided an available seed source in case fire decimated adjacent stands. Close

• 2170. [Article] Application of the carbon/nitrogen balance concept to predicting the nutritional quality of blueberry foliage to deer in southeastern Alaska

  Sitka black-tailed deer (Odocoileus hemionus sitkensis Sm.) prefer understory forages growing beneath a forest canopy despite a greater abundance of the same plant species in forest clearings. This research ...

  Citation × Citation Citation Abstract Copy Title: Application of the carbon/nitrogen balance concept to predicting the nutritional quality of blueberry foliage to deer in southeastern Alaska Author: Rose, Cathy L. Sitka black-tailed deer (Odocoileus hemionus sitkensis Sm.) prefer understory forages growing beneath a forest canopy despite a greater abundance of the same plant species in forest clearings. This research examined responses of the deciduous shrub - blueberry (Vaccinium ovalifolium), to test the hypotheses that 1) forage is less nutritious and less palatable when grown in clearings than in forest understories, and that 2) changes in the plant carbon/nitrogen (C/N) ratio in response to light and nitrogen supply determine forage nutritional quality. Responses to irradiance and nitrogen supply were examined with respect to plant physiology, morphology, biochemistry and nutritional quality in three phases : 1) under controlled conditions in a growth room, 2) with manipulations in a field experiment and 3) along natural gradients of light and nitrogen in the native forests. The results were highly consistent from the growth room to the field. Light strongly affected plant physiological responses, including photosynthesis, relative growth rates and growth efficiency, whereas nitrogen had little effect. In regression analyses, leaf morphological properties, including specific leaf weight and leaf succulence, were the best predictors of relative growth rates (R2=.67). Irrespective of nitrogen supply, the biochemical properties of sun leaves included higher concentrations of starch, nonstructural carbohydrates and % lignin + cutin in the cell wall, but lower concentrations of structural polymers, total nitrogen, free amino acids, and ratio of free amino acids : total N, compared to shade leaves. Sun leaves also were slightly higher in digestible energy, much lower in digestible nitrogen and presumably less palatable due to higher tannin concentrations, compared to shade leaves. Tannins were directly correlated to specific leaf weight (R2=.89). Regression equations based upon specific leaf weight, leaf succulence and leaf structural polymers accurately predicted field values for digestible nitrogen (R2=.91) and digestible energy (R2=.96) in foliage. Nutritional properties of blueberry forage grown under variable irradiance in the natural stands matched predictions based upon results from the growth room and field. Compared to even-aged stands and oldgrowth, leaves of plants grown in clear-cuts were similar in digestible energy, much lower in digestible nitrogen, and presumably less palatable due to higher tannin concentrations. Title: Application of the carbon/nitrogen balance concept to predicting the nutritional quality of blueberry foliage to deer in southeastern Alaska Author: Rose, Cathy L. Sitka black-tailed deer (Odocoileus hemionus sitkensis Sm.) prefer understory forages growing beneath a forest canopy despite a greater abundance of the same plant species in forest clearings. This research examined responses of the deciduous shrub - blueberry (Vaccinium ovalifolium), to test the hypotheses that 1) forage is less nutritious and less palatable when grown in clearings than in forest understories, and that 2) changes in the plant carbon/nitrogen (C/N) ratio in response to light and nitrogen supply determine forage nutritional quality. Responses to irradiance and nitrogen supply were examined with respect to plant physiology, morphology, biochemistry and nutritional quality in three phases : 1) under controlled conditions in a growth room, 2) with manipulations in a field experiment and 3) along natural gradients of light and nitrogen in the native forests. The results were highly consistent from the growth room to the field. Light strongly affected plant physiological responses, including photosynthesis, relative growth rates and growth efficiency, whereas nitrogen had little effect. In regression analyses, leaf morphological properties, including specific leaf weight and leaf succulence, were the best predictors of relative growth rates (R2=.67). Irrespective of nitrogen supply, the biochemical properties of sun leaves included higher concentrations of starch, nonstructural carbohydrates and % lignin + cutin in the cell wall, but lower concentrations of structural polymers, total nitrogen, free amino acids, and ratio of free amino acids : total N, compared to shade leaves. Sun leaves also were slightly higher in digestible energy, much lower in digestible nitrogen and presumably less palatable due to higher tannin concentrations, compared to shade leaves. Tannins were directly correlated to specific leaf weight (R2=.89). Regression equations based upon specific leaf weight, leaf succulence and leaf structural polymers accurately predicted field values for digestible nitrogen (R2=.91) and digestible energy (R2=.96) in foliage. Nutritional properties of blueberry forage grown under variable irradiance in the natural stands matched predictions based upon results from the growth room and field. Compared to even-aged stands and oldgrowth, leaves of plants grown in clear-cuts were similar in digestible energy, much lower in digestible nitrogen, and presumably less palatable due to higher tannin concentrations. Close