Search

Search Results

• 701. [Article] Effect of seed deterioration on germination of wheat under environmental stresses

  Germinating seeds often encounter stress conditions of temperature, moisture and oxygen in the field. Germination tests conducted under these stress conditions in the laboratory might be methods of differentiating ...

  Citation × Citation Citation Abstract Copy Title: Effect of seed deterioration on germination of wheat under environmental stresses Author: Than, Mya Germinating seeds often encounter stress conditions of temperature, moisture and oxygen in the field. Germination tests conducted under these stress conditions in the laboratory might be methods of differentiating high and low vigor seeds. The objectives of this study were to (1) determine if these stress conditions reduce germination performance of low vigor seeds more than high vigor seeds, and (2) determine the potential for using one or more of these stress environmental conditions as the basis of a vigor test to predict relative field performance of wheat seed. Seed lots of varying levels of deterioration were produced by artificial aging of 'Malcolm' wheat (Triticum aestivum L.). Germination tests were conducted at temperatures of 5, 10, 15, 20, 25, and 30°C; water potentials of 0, -0.2, -0.4, -0.6, -0.8, -1.0, -1.2, and -1.4 MPa; and oxygen levels of 2, 4, 8, 12, 16% and air (21%). The water and oxygen stresses were applied at six temperatures. Laboratory germination results were compared to field emergence percentages of artificially and naturally aged seed lots. Germination percentage and rate of germination of low vigor seeds were depressed more than that of high vigor seeds at all water potentials and temperatures. At 20°C, for example, germination percentage of high, medium and low vigor seed lots at -0.6 MPa were 76, 48 and 29% respectively, compared to nearly 100% at 0, -0.2 and -0.4 MPa. Similar relationships existed at the other temperatures. Germination of low vigor seed generally declined with each reduction of oxygen level while that of high vigor seed remained nearly constant. The germination differential between high and low vigor seed lots widened to as much as 30% in 2% oxygen at 30°C. Twenty-four naturally-aged seed lots representing six varieties and four production years were evaluated for germination under water stress and field emergence. Correlation coefficients between germination at -0.6 MPa and field emergence were 0.61** and 0.59** for untreated and Arasan-treated seeds, respectively. It is clear from these studies that environmental stresses reduce the germination of low vigor seeds more than that of high vigor seeds. A vigor test based on one or more of these stresses has potential for being a practical and realistic method of predicting the relative field performance of wheat seed lots. Title: Effect of seed deterioration on germination of wheat under environmental stresses Author: Than, Mya Germinating seeds often encounter stress conditions of temperature, moisture and oxygen in the field. Germination tests conducted under these stress conditions in the laboratory might be methods of differentiating high and low vigor seeds. The objectives of this study were to (1) determine if these stress conditions reduce germination performance of low vigor seeds more than high vigor seeds, and (2) determine the potential for using one or more of these stress environmental conditions as the basis of a vigor test to predict relative field performance of wheat seed. Seed lots of varying levels of deterioration were produced by artificial aging of 'Malcolm' wheat (Triticum aestivum L.). Germination tests were conducted at temperatures of 5, 10, 15, 20, 25, and 30°C; water potentials of 0, -0.2, -0.4, -0.6, -0.8, -1.0, -1.2, and -1.4 MPa; and oxygen levels of 2, 4, 8, 12, 16% and air (21%). The water and oxygen stresses were applied at six temperatures. Laboratory germination results were compared to field emergence percentages of artificially and naturally aged seed lots. Germination percentage and rate of germination of low vigor seeds were depressed more than that of high vigor seeds at all water potentials and temperatures. At 20°C, for example, germination percentage of high, medium and low vigor seed lots at -0.6 MPa were 76, 48 and 29% respectively, compared to nearly 100% at 0, -0.2 and -0.4 MPa. Similar relationships existed at the other temperatures. Germination of low vigor seed generally declined with each reduction of oxygen level while that of high vigor seed remained nearly constant. The germination differential between high and low vigor seed lots widened to as much as 30% in 2% oxygen at 30°C. Twenty-four naturally-aged seed lots representing six varieties and four production years were evaluated for germination under water stress and field emergence. Correlation coefficients between germination at -0.6 MPa and field emergence were 0.61** and 0.59** for untreated and Arasan-treated seeds, respectively. It is clear from these studies that environmental stresses reduce the germination of low vigor seeds more than that of high vigor seeds. A vigor test based on one or more of these stresses has potential for being a practical and realistic method of predicting the relative field performance of wheat seed lots. Close

• 702. [Article] Geochemical and helium isotopic variability within the Lau Basin

  This research incorporates geochemical and helium isotopic analyses of Lau Basin volcanic glasses, along with helium isotopic analyses of water column hydrothermal plumes to better understand the processes ...

  Citation × Citation Citation Abstract Copy Title: Geochemical and helium isotopic variability within the Lau Basin Author: Goddard, Charlotte Ives This research incorporates geochemical and helium isotopic analyses of Lau Basin volcanic glasses, along with helium isotopic analyses of water column hydrothermal plumes to better understand the processes that control the formation and evolution of this backarc basin. Lavas newly collected from the four southernmost segments of the Valu Fa Ridge (VFR) reveal gradients in element ratios such as Ba/Nb along axis over the 75 km length of the study area, and show an increase in arc-like geochemical signature to the south. Basalts from the VFR segments and the off-axis volcanoes are derived by 10–20% melting of a source that was previously melted 0.5–1.5% in association with arc volcanism. Melt fraction increases southwards along axis from ~10–15% and ranges up to 20% for the seamounts. 3He/4He ratios in glasses along the Eastern Lau Spreading Center (ELSC), from 20º–22º45’S, reveal an along-axis gradient. 3He/4He decreases from 9.6 RA in basalts at the Intermediate Lau Spreading Center-Eastern Lau Spreading Center transition, to 5.4 RA in low silica lavas at the southern end of the VFR. The decrease in the maximum 3He/4He towards the south is ascribed to mantle heterogeneity. The increased variability in 3He/4He along the VFR is due to processes occurring during prolonged residence of magma in the crust prior to eruption. Basalt 3He/4He values are similar to those measured from high-temperature vent fluids in the same region (Proskurowski et al., 2006). Neutrally buoyant plumes with detectable 3He anomalies (δ3He=65–70%) were present in all of the areas sampled, indicating an abundance of hydrothermal activity along the ELSC. Buoyant plumes with higher δ3He (100–225%) were sampled at two of the target areas. The δ3He anomalies revealed by the hydrocast profiles are ~200 m thick at each site. The depth of the neutrally buoyant hydrothermal plumes shallows from 2300–2600 m in the north to 1600–1800 m in the south. This change occurs in conjunction with the shallowing of the ELSC ridge axis, which is further enhanced by a transition in ridge morphology from axial valley to axial high at 20º 30’S. 3He/heat ratios of 1–2.8×10-17 mol J-1 are calculated for the neutrally buoyant plumes, while lower values of 0.8×10-17 mol J-1 are calculated for the buoyant plumes. These values are similar to those observed in vent fluids sampled from relatively mature hydrothermal systems along mid-ocean ridges (e.g., EPR at 21ºN, Cleft segment of the Juan de Fuca Ridge and TAG at 26ºN along the MAR), and about an order of magnitude less than values observed over young lava flows from recently perturbed magmatic systems. Title: Geochemical and helium isotopic variability within the Lau Basin Author: Goddard, Charlotte Ives This research incorporates geochemical and helium isotopic analyses of Lau Basin volcanic glasses, along with helium isotopic analyses of water column hydrothermal plumes to better understand the processes that control the formation and evolution of this backarc basin. Lavas newly collected from the four southernmost segments of the Valu Fa Ridge (VFR) reveal gradients in element ratios such as Ba/Nb along axis over the 75 km length of the study area, and show an increase in arc-like geochemical signature to the south. Basalts from the VFR segments and the off-axis volcanoes are derived by 10–20% melting of a source that was previously melted 0.5–1.5% in association with arc volcanism. Melt fraction increases southwards along axis from ~10–15% and ranges up to 20% for the seamounts. 3He/4He ratios in glasses along the Eastern Lau Spreading Center (ELSC), from 20º–22º45’S, reveal an along-axis gradient. 3He/4He decreases from 9.6 RA in basalts at the Intermediate Lau Spreading Center-Eastern Lau Spreading Center transition, to 5.4 RA in low silica lavas at the southern end of the VFR. The decrease in the maximum 3He/4He towards the south is ascribed to mantle heterogeneity. The increased variability in 3He/4He along the VFR is due to processes occurring during prolonged residence of magma in the crust prior to eruption. Basalt 3He/4He values are similar to those measured from high-temperature vent fluids in the same region (Proskurowski et al., 2006). Neutrally buoyant plumes with detectable 3He anomalies (δ3He=65–70%) were present in all of the areas sampled, indicating an abundance of hydrothermal activity along the ELSC. Buoyant plumes with higher δ3He (100–225%) were sampled at two of the target areas. The δ3He anomalies revealed by the hydrocast profiles are ~200 m thick at each site. The depth of the neutrally buoyant hydrothermal plumes shallows from 2300–2600 m in the north to 1600–1800 m in the south. This change occurs in conjunction with the shallowing of the ELSC ridge axis, which is further enhanced by a transition in ridge morphology from axial valley to axial high at 20º 30’S. 3He/heat ratios of 1–2.8×10-17 mol J-1 are calculated for the neutrally buoyant plumes, while lower values of 0.8×10-17 mol J-1 are calculated for the buoyant plumes. These values are similar to those observed in vent fluids sampled from relatively mature hydrothermal systems along mid-ocean ridges (e.g., EPR at 21ºN, Cleft segment of the Juan de Fuca Ridge and TAG at 26ºN along the MAR), and about an order of magnitude less than values observed over young lava flows from recently perturbed magmatic systems. Close

• 703. [Article] Validity and reliability analysis of Cooper's 12-minute run and the multistage shuttle run in healthy adults

  Field tests are often the most practical method to assess aerobic fitness, but demonstrate greater error variability than laboratory tests. Researchers can improve field tests by identifying factors that ...

  Citation × Citation Citation Abstract Copy Title: Validity and reliability analysis of Cooper's 12-minute run and the multistage shuttle run in healthy adults Author: Penry, Jason Talmadge, 1976- Field tests are often the most practical method to assess aerobic fitness, but demonstrate greater error variability than laboratory tests. Researchers can improve field tests by identifying factors that contribute to systematic error in VO₂max estimation. PURPOSE: To examine the validity and reliability evidence of two field tests of aerobic fitness: Cooper's 12-minute run (12MR) and the multistage shuttle run (MSR). METHODS: Sixty participants (mean age = 21.8 ± 3.6y), completed three trials (occasion) of each field test (instrument) for a total of six test trials. To estimate overall reliability and evaluate possible sources of error in the field tests, a psychometric statistical tool called generalizability study (G-study) was employed. This analysis utilized a two-random facet design (occasion and instrument) in a completely crossed ANOVA. In addition, criterion VO₂max was assessed in a subgroup of volunteers (n = 21) via an incremental treadmill run and expired gas analysis (TR). Each participant completed the study within a six-week period. RESULTS: G-study analysis of the two field tests returned a high reliability coefficient (φ = 0.96), with the largest amount of systematic error variance (4.3%) attributable to an interaction between participants and test occasions. This mild interaction suggests certain test participants demonstrated larger error variability across test occasions than other participants. The MSR predicted VO₂max values lower than those measured in the laboratory setting (p < 0.01; paired t-tests), while 12MR and TR scores were not different (p > 0.05). The 12MR underestimated VO₂max values at lower aerobic fitness levels and overestimated VO₂max values in individuals demonstrating greater aerobic fitness, which was not observed in the MSR data. CONCLUSIONS: These results suggest high reliability for VO₂max field tests in young, healthy individuals. However, test administrators must use caution when attempting to use field test data to predict criterion VO₂max scores. While test participants can be expected to attain MSR scores significantly lower than the criterion value, the consistent mean bias across VO₂max values makes the MSR a more useful test when comparing test participants. Title: Validity and reliability analysis of Cooper's 12-minute run and the multistage shuttle run in healthy adults Author: Penry, Jason Talmadge, 1976- Field tests are often the most practical method to assess aerobic fitness, but demonstrate greater error variability than laboratory tests. Researchers can improve field tests by identifying factors that contribute to systematic error in VO₂max estimation. PURPOSE: To examine the validity and reliability evidence of two field tests of aerobic fitness: Cooper's 12-minute run (12MR) and the multistage shuttle run (MSR). METHODS: Sixty participants (mean age = 21.8 ± 3.6y), completed three trials (occasion) of each field test (instrument) for a total of six test trials. To estimate overall reliability and evaluate possible sources of error in the field tests, a psychometric statistical tool called generalizability study (G-study) was employed. This analysis utilized a two-random facet design (occasion and instrument) in a completely crossed ANOVA. In addition, criterion VO₂max was assessed in a subgroup of volunteers (n = 21) via an incremental treadmill run and expired gas analysis (TR). Each participant completed the study within a six-week period. RESULTS: G-study analysis of the two field tests returned a high reliability coefficient (φ = 0.96), with the largest amount of systematic error variance (4.3%) attributable to an interaction between participants and test occasions. This mild interaction suggests certain test participants demonstrated larger error variability across test occasions than other participants. The MSR predicted VO₂max values lower than those measured in the laboratory setting (p < 0.01; paired t-tests), while 12MR and TR scores were not different (p > 0.05). The 12MR underestimated VO₂max values at lower aerobic fitness levels and overestimated VO₂max values in individuals demonstrating greater aerobic fitness, which was not observed in the MSR data. CONCLUSIONS: These results suggest high reliability for VO₂max field tests in young, healthy individuals. However, test administrators must use caution when attempting to use field test data to predict criterion VO₂max scores. While test participants can be expected to attain MSR scores significantly lower than the criterion value, the consistent mean bias across VO₂max values makes the MSR a more useful test when comparing test participants. Close

• 704. [Article] House design scores of forty Corvallis, Oregon, residences related to homemakers' expressed satisfaction and ranking of values

  The purpose of this study was to gain information regarding interrelationships among homemakers' expressed satisfaction with their houses, their expressed hierarchy of values and house design scores. The ...

  Citation × Citation Citation Abstract Copy Title: House design scores of forty Corvallis, Oregon, residences related to homemakers' expressed satisfaction and ranking of values Author: Teitzel, Freda Anne The purpose of this study was to gain information regarding interrelationships among homemakers' expressed satisfaction with their houses, their expressed hierarchy of values and house design scores. The sample consisted of 40 homemakers who lived in owner-occupied residences located in Corvallis, Oregon, constructed since 1955, and ranging in size from 1200 to 1700 square feet. Cooperators were limited to persons who had not employed an architect or designed their own house. Data were collected by interviews with homemakers and included: (1) general information about the homemaker, her family and their house, (2) an expressed satisfaction score based on principles developed by the American Public Health Association, (3) the hierarchy of nine values determined by previous research as having relevance in housing, and (4) a house design score using plan-evaluation check lists. The families ranged in size from two to seven persons with the median being four. One-half of the homemakers were tinder 35 and 82.5 percent were high school graduates. Approximately 62 percent of the families were in the expanding stage of the family life cycle. Forty percent of the families were in social position IV as determined by Hollingshead's Two Factor Index of Social Position. The median size of the houses was in the 1300 to 1399 square feet category; the median price range fell into the $17,000 to $17,999 category. Over three-fifths of the homemakers had made no changes in the original floor plan of the house they selected. Fifty percent of the families had lived in their present house fewer than three years. The majority of homemakers interviewed seemed satisfied with their houses, especially in regard to wiring, daylight illumination, facilities for cleanliness, and protection against contagion and accidents. Storage and adequate space for guests, privacy, and individual interests of family members as well as noise were found unsatisfactory by a number of homemakers. Many homemakers mentioned they would, in buying another house, desire family rooms, more than one bathroom, larger bedrooms, and a front entry. Nearly five-eighths of the homemakers wanted some part of their houses enlarged. In general homemakers with smaller families including those without children or with children over 18 expressed the most satisfaction with the type of house included in the study. Homemakers who were not high school graduates and those over 40 years old expressed greater satisfaction with their houses than other respondents. If the plans were selected prior to building the house, the homemakers expressed more satisfaction with their houses than if the houses were completely built when purchased. Homemakers who had lived in their houses fewer than two years were more satisfied than the other respondents. Homemakers living in more expensive houses expressed greater satisfaction than those in less expensive houses. A correlation coefficient of .52 between the design of the house as rated on house plan-evaluation check lists and the homemakers' expressed satisfaction with the house was significant at the 1% level of probability. Significant correlation coefficients were found between expressed satisfaction and three of the specific topics of the check lists: landscape (.40), circulation (.42) and kitchens (.56). The correlation coefficient of -37 between the ranking of the value aesthetics and the expressed satisfaction score was significant at the 2% level of probability. House design scores and values were found to have no correlation in this study. Title: House design scores of forty Corvallis, Oregon, residences related to homemakers' expressed satisfaction and ranking of values Author: Teitzel, Freda Anne The purpose of this study was to gain information regarding interrelationships among homemakers' expressed satisfaction with their houses, their expressed hierarchy of values and house design scores. The sample consisted of 40 homemakers who lived in owner-occupied residences located in Corvallis, Oregon, constructed since 1955, and ranging in size from 1200 to 1700 square feet. Cooperators were limited to persons who had not employed an architect or designed their own house. Data were collected by interviews with homemakers and included: (1) general information about the homemaker, her family and their house, (2) an expressed satisfaction score based on principles developed by the American Public Health Association, (3) the hierarchy of nine values determined by previous research as having relevance in housing, and (4) a house design score using plan-evaluation check lists. The families ranged in size from two to seven persons with the median being four. One-half of the homemakers were tinder 35 and 82.5 percent were high school graduates. Approximately 62 percent of the families were in the expanding stage of the family life cycle. Forty percent of the families were in social position IV as determined by Hollingshead's Two Factor Index of Social Position. The median size of the houses was in the 1300 to 1399 square feet category; the median price range fell into the $17,000 to $17,999 category. Over three-fifths of the homemakers had made no changes in the original floor plan of the house they selected. Fifty percent of the families had lived in their present house fewer than three years. The majority of homemakers interviewed seemed satisfied with their houses, especially in regard to wiring, daylight illumination, facilities for cleanliness, and protection against contagion and accidents. Storage and adequate space for guests, privacy, and individual interests of family members as well as noise were found unsatisfactory by a number of homemakers. Many homemakers mentioned they would, in buying another house, desire family rooms, more than one bathroom, larger bedrooms, and a front entry. Nearly five-eighths of the homemakers wanted some part of their houses enlarged. In general homemakers with smaller families including those without children or with children over 18 expressed the most satisfaction with the type of house included in the study. Homemakers who were not high school graduates and those over 40 years old expressed greater satisfaction with their houses than other respondents. If the plans were selected prior to building the house, the homemakers expressed more satisfaction with their houses than if the houses were completely built when purchased. Homemakers who had lived in their houses fewer than two years were more satisfied than the other respondents. Homemakers living in more expensive houses expressed greater satisfaction than those in less expensive houses. A correlation coefficient of .52 between the design of the house as rated on house plan-evaluation check lists and the homemakers' expressed satisfaction with the house was significant at the 1% level of probability. Significant correlation coefficients were found between expressed satisfaction and three of the specific topics of the check lists: landscape (.40), circulation (.42) and kitchens (.56). The correlation coefficient of -37 between the ranking of the value aesthetics and the expressed satisfaction score was significant at the 2% level of probability. House design scores and values were found to have no correlation in this study. Close

• 705. [Article] A formal model of construction safety and health risk management

  Despite recent efforts to improve site safety, construction still accounts for a disproportionate injury and illness rate. According to the 2007 injury and illness data released by the National Safety ...

  Citation × Citation Citation Abstract Copy Title: A formal model of construction safety and health risk management Author: Hallowell, Matthew Ryan Despite recent efforts to improve site safety, construction still accounts for a disproportionate injury and illness rate. According to the 2007 injury and illness data released by the National Safety Council, the construction industry has a fatality and disabling injury rate that is approximately three times higher than the all-industry average. The transient, unique, and complex nature of construction projects makes safety management exceptionally difficult. Most construction safety efforts are applied in an informal fashion under the premise that simply allocating more resources to safety management will improve site safety. Currently, there is no mechanism by which construction site safety professionals may formally select safety program elements for a particular process. This dissertation describes a research effort that introduces, populates, and validates a formal method to evaluate construction safety risk and strategically match safety program elements to construction processes. The decision scheme introduced, based on the application of Newton’s third law, assumes that every construction activity is associated with specific safety risks and that each safety program element is capable of mitigating a portion of such risks. Using the high-risk process of constructing concrete formwork as an example, the theoretical model was populated. Data was obtained using the Delphi method, a systematic and interactive research technique for obtaining the judgment of a panel of independent experts. The results of this research include the quantification of probability and severity values for ten mutually-exclusive and all-inclusive safety risks associated with thirteen worker-activities required to construct concrete formwork. Additionally, the study quantified the probability and severity reduction values resulting from the implementation of thirteen safety program elements. The data can be used to improve safety management techniques in several ways. First, cumulative risk may be tracked throughout a work period allowing safety managers to identify and avoid periods of exceptionally high safety risk. Second, safety managers may strategically select safety program elements based on the ability to reduce portions of specific risks. Finally, the balance between cumulative risk and the safety mitigation can be evaluated. The results of this research indicate that the highest risk activities for formwork construction are form lubrication and preparation, ascending and descending ladders, and accepting and loading materials with a crane. The most effective safety program elements are upper management support and commitment, subcontractor selection and management, and employee involvement in safety management and planning. The risk values for formwork construction and the risk reduction values associated with safety program elements can be used to determine the appropriate scope and focus of safety and health management efforts. The methods used to quantify these values may be applied to any construction process or safety program. Title: A formal model of construction safety and health risk management Author: Hallowell, Matthew Ryan Despite recent efforts to improve site safety, construction still accounts for a disproportionate injury and illness rate. According to the 2007 injury and illness data released by the National Safety Council, the construction industry has a fatality and disabling injury rate that is approximately three times higher than the all-industry average. The transient, unique, and complex nature of construction projects makes safety management exceptionally difficult. Most construction safety efforts are applied in an informal fashion under the premise that simply allocating more resources to safety management will improve site safety. Currently, there is no mechanism by which construction site safety professionals may formally select safety program elements for a particular process. This dissertation describes a research effort that introduces, populates, and validates a formal method to evaluate construction safety risk and strategically match safety program elements to construction processes. The decision scheme introduced, based on the application of Newton’s third law, assumes that every construction activity is associated with specific safety risks and that each safety program element is capable of mitigating a portion of such risks. Using the high-risk process of constructing concrete formwork as an example, the theoretical model was populated. Data was obtained using the Delphi method, a systematic and interactive research technique for obtaining the judgment of a panel of independent experts. The results of this research include the quantification of probability and severity values for ten mutually-exclusive and all-inclusive safety risks associated with thirteen worker-activities required to construct concrete formwork. Additionally, the study quantified the probability and severity reduction values resulting from the implementation of thirteen safety program elements. The data can be used to improve safety management techniques in several ways. First, cumulative risk may be tracked throughout a work period allowing safety managers to identify and avoid periods of exceptionally high safety risk. Second, safety managers may strategically select safety program elements based on the ability to reduce portions of specific risks. Finally, the balance between cumulative risk and the safety mitigation can be evaluated. The results of this research indicate that the highest risk activities for formwork construction are form lubrication and preparation, ascending and descending ladders, and accepting and loading materials with a crane. The most effective safety program elements are upper management support and commitment, subcontractor selection and management, and employee involvement in safety management and planning. The risk values for formwork construction and the risk reduction values associated with safety program elements can be used to determine the appropriate scope and focus of safety and health management efforts. The methods used to quantify these values may be applied to any construction process or safety program. Close

• 706. [Article] Statistical enhancement of support vector machines

  Support Vector Machines (SVM) and Random Forests (RF) have consistently outperformed other machine learning algorithms on a variety of problems. SVM can be used for classification and regression on many ...

  Citation × Citation Citation Abstract Copy Title: Statistical enhancement of support vector machines Author: Taylor, Aimee Elizabeth Support Vector Machines (SVM) and Random Forests (RF) have consistently outperformed other machine learning algorithms on a variety of problems. SVM can be used for classification and regression on many types of data (e.g. nonlinear, high dimensional), but cannot handle missing or mixed data. This research implements a permutation-based variable importance measure and missing value imputation method for SVM founded on similar techniques developed for RF. The results of the SVM variable importance measure are compared to RF results on simulated data sets with known variable importance. The variability of the importance outcomes are examined when different tuning parameter values (for SVM and RF) and kernels (for SVM) are used on benchmark data sets. Two of the benchmark data sets are also used to evaluate the missing value imputation method. The variable importance measure developed in this study has comparable results to RF on the simulated data sets. However, the results have greater variability and less consistency than RF on the same benchmark data sets for the tuning parameter values investigated. SVM often had a smaller test error than RF, indicating that SVM was able to better fit the benchmark data. Unlike the RF results, the SVM variable importance results can be highly sensitive to the choice of tuning parameters. Successive grid searches are needed to tune these parameters and achieve more consistent SVM variable importance results. This research compares a median-based missing value imputation method to a mean-based approach. The quality of the methods was evaluated by comparing the test set error (or test mean-square error) achieved after application to two benchmark data sets. There is improvement on a regression data set, but no significant difference in results for a classification example. Further investigation is needed to evaluate this imputation technique. A variable importance measure for SVM provides insight into which explanatory variables are important in determining the response. SVM has been known to perform better than other machine learning algorithms on some data sets. By developing such a measure, this research has furthered the capabilities of an important algorithm used for data mining. Title: Statistical enhancement of support vector machines Author: Taylor, Aimee Elizabeth Support Vector Machines (SVM) and Random Forests (RF) have consistently outperformed other machine learning algorithms on a variety of problems. SVM can be used for classification and regression on many types of data (e.g. nonlinear, high dimensional), but cannot handle missing or mixed data. This research implements a permutation-based variable importance measure and missing value imputation method for SVM founded on similar techniques developed for RF. The results of the SVM variable importance measure are compared to RF results on simulated data sets with known variable importance. The variability of the importance outcomes are examined when different tuning parameter values (for SVM and RF) and kernels (for SVM) are used on benchmark data sets. Two of the benchmark data sets are also used to evaluate the missing value imputation method. The variable importance measure developed in this study has comparable results to RF on the simulated data sets. However, the results have greater variability and less consistency than RF on the same benchmark data sets for the tuning parameter values investigated. SVM often had a smaller test error than RF, indicating that SVM was able to better fit the benchmark data. Unlike the RF results, the SVM variable importance results can be highly sensitive to the choice of tuning parameters. Successive grid searches are needed to tune these parameters and achieve more consistent SVM variable importance results. This research compares a median-based missing value imputation method to a mean-based approach. The quality of the methods was evaluated by comparing the test set error (or test mean-square error) achieved after application to two benchmark data sets. There is improvement on a regression data set, but no significant difference in results for a classification example. Further investigation is needed to evaluate this imputation technique. A variable importance measure for SVM provides insight into which explanatory variables are important in determining the response. SVM has been known to perform better than other machine learning algorithms on some data sets. By developing such a measure, this research has furthered the capabilities of an important algorithm used for data mining. Close

• 707. [Article] Survey of graduates and undergraduates of North Douglas School District to determine needed improvements in career education

  School systems have an important responsibility to continuously examine and review their educational programs to determine if the programs satisfy the needs of the youth they serve. Systematically collected ...

  Citation × Citation Citation Abstract Copy Title: Survey of graduates and undergraduates of North Douglas School District to determine needed improvements in career education Author: Smith, Richard Alan School systems have an important responsibility to continuously examine and review their educational programs to determine if the programs satisfy the needs of the youth they serve. Systematically collected data derived from former and present students can enable the school system to appraise its effectiveness in fulfilling the aim it has identified and to provide a basis for sound decision making and planning for the future. The purpose of this study was to obtain and analyze graduate and in-school student data that could assist planning toward improvement of the career education program in the North Douglas School District. A total of 317 graduates from North Douglas High School, covering a nine year period from 1962 through 1970, were selected to participate in a follow-up survey through a mailed questionnaire interview. Additionally, 348 in-school students in grades 6-12 of North Douglas School District were selected to participate in an interest survey through the administration of a questionnaire designed to secure information about occupational and educational objectives. The specific criteria on which the study was based were: occupational status, post high school education, income, number of jobs held, location of residence, value of high school training, job satisfaction, high school completion, post high school plans, student training desires, student occupational interest. The following conclusions are based on the findings of this study: (1) The longer students have been out of school the more likely they are to be full-time employed. (2) The longer students have been out of school the more likely they are to be employed in occupations requiring additional training and/or experience. (3) Most post high school education is obtained in a college or university. (4) Additional training and experience contribute significantly to income. (5) A large number of graduates obtain employment outside of Douglas County. (6) English and mathematics are the two most important high school courses for finding and keeping jobs. (7) The majority of in-school students feel that high school completion is important. (8) A need exists for college preparation and occupational training to be an integral part of the curriculum. (9) Students are not receiving adequate guidance and counseling prior to graduation. (10) Students need a marketable skill upon graduation from high school. (11) Post high school training is deemed important in obtaining satisfying employment. Title: Survey of graduates and undergraduates of North Douglas School District to determine needed improvements in career education Author: Smith, Richard Alan School systems have an important responsibility to continuously examine and review their educational programs to determine if the programs satisfy the needs of the youth they serve. Systematically collected data derived from former and present students can enable the school system to appraise its effectiveness in fulfilling the aim it has identified and to provide a basis for sound decision making and planning for the future. The purpose of this study was to obtain and analyze graduate and in-school student data that could assist planning toward improvement of the career education program in the North Douglas School District. A total of 317 graduates from North Douglas High School, covering a nine year period from 1962 through 1970, were selected to participate in a follow-up survey through a mailed questionnaire interview. Additionally, 348 in-school students in grades 6-12 of North Douglas School District were selected to participate in an interest survey through the administration of a questionnaire designed to secure information about occupational and educational objectives. The specific criteria on which the study was based were: occupational status, post high school education, income, number of jobs held, location of residence, value of high school training, job satisfaction, high school completion, post high school plans, student training desires, student occupational interest. The following conclusions are based on the findings of this study: (1) The longer students have been out of school the more likely they are to be full-time employed. (2) The longer students have been out of school the more likely they are to be employed in occupations requiring additional training and/or experience. (3) Most post high school education is obtained in a college or university. (4) Additional training and experience contribute significantly to income. (5) A large number of graduates obtain employment outside of Douglas County. (6) English and mathematics are the two most important high school courses for finding and keeping jobs. (7) The majority of in-school students feel that high school completion is important. (8) A need exists for college preparation and occupational training to be an integral part of the curriculum. (9) Students are not receiving adequate guidance and counseling prior to graduation. (10) Students need a marketable skill upon graduation from high school. (11) Post high school training is deemed important in obtaining satisfying employment. Close

• 708. [Article] A study of the relationship between attitudes toward business and level of occupational aspiration

  The purpose of this study was to determine a student's attitudes toward business, his level of occupational aspiration, and the degree of correlation between them. Two questionnaires were used: Student ...

  Citation × Citation Citation Abstract Copy Title: A study of the relationship between attitudes toward business and level of occupational aspiration Author: Kashuba, Steven Carson, 1935- The purpose of this study was to determine a student's attitudes toward business, his level of occupational aspiration, and the degree of correlation between them. Two questionnaires were used: Student Attitudes Toward Business and Level of Occupational Aspiration. The business attitude questionnaire elicited student reactions to 87 business-related statements. The occupational aspiration questionnaire sought biographical information and responses pertaining to a student's idealistic shortrange, idealistic long-range, realistic short-range, and realistic long-range occupational aspirations. This study found that senior high school students' attitudes toward business were not significantly correlated with their level of occupational aspiration when compared by sex and intelligence. However, significant differences were found when student attitudes were correlated with level of occupational aspiration by high school (socioeconomic area) and by high school pattern (academic, business, and general education). Students coming from a high socioeconomic area and attending a high school in a high socioeconomic area scored significantly higher on the business attitude questionnaire than did the other two groups. Students enrolled in an academic pattern (college or university preparatory) scored significantly higher on the business attitude questionnaire than did business education students. Business and general education students' scores were not significantly different. Senior high school academic students' levels of occupational aspiration were significantly higher than those of business and general education students. However, the occupational aspirations of students in the business educa-pattern were not significantly higher than those of general education students. This study found a significant correlation between a senior high school students's concept of self (the strength of his feelings about his ability, chances of getting ahead, value of education and educational aspirations) and his level of occupational aspiration. A student's concept of self and attitudes toward business scores were not significantly correlated. Senior high school students' scholastic achievement (grade 11 scholastic average) was found to be significantly correlated with their levels of occupational aspiration. Their attitudes toward business scores, meanwhile, were not significantly correlated with their level of occupational aspiration at any of the four levels of intelligence (IQ). Nor was there a significant correlation between student attitudes toward business and scholastic achievement. Twenty-eight per cent of the students tested indicated that their parents were the greatest single influence on their educational aspirations and 43 per cent indicated that they made their own educational decisions. Academic students did, however, cite their parents as being the most influential factor significantly more often than did non-academic students. Over 60 per cent of the students reported that they made their own occupational decisions, while 10 per cent regarded their parents as being the greatest single influence on their occupational decisions. Academic students reported that their parents were more instrumental in their decisions than did non-academic students. Six per cent of the academic students and 25 per cent of the business and general education students felt that circumstances such as grades, attendance record, and interests were responsible for their choice of a high school educational program. Thirty per cent of the business education students reported that the most important consideration in their choice of an occupation was money, while 20 per cent of the academic and general education students chose money as the most important consideration. On the average, the educational aspiration of the group tested was slightly higher than a baccalaureate degree; the educational aspiration of the academic group was significantly higher than that of the other two groups. The realistic long-range occupational aspirations of the group were significantly higher than their short-range realistic aspirations, and their long-range idealistic occupational aspirations were significantly higher than their short-range idealistic occupational aspirations. Title: A study of the relationship between attitudes toward business and level of occupational aspiration Author: Kashuba, Steven Carson, 1935- The purpose of this study was to determine a student's attitudes toward business, his level of occupational aspiration, and the degree of correlation between them. Two questionnaires were used: Student Attitudes Toward Business and Level of Occupational Aspiration. The business attitude questionnaire elicited student reactions to 87 business-related statements. The occupational aspiration questionnaire sought biographical information and responses pertaining to a student's idealistic shortrange, idealistic long-range, realistic short-range, and realistic long-range occupational aspirations. This study found that senior high school students' attitudes toward business were not significantly correlated with their level of occupational aspiration when compared by sex and intelligence. However, significant differences were found when student attitudes were correlated with level of occupational aspiration by high school (socioeconomic area) and by high school pattern (academic, business, and general education). Students coming from a high socioeconomic area and attending a high school in a high socioeconomic area scored significantly higher on the business attitude questionnaire than did the other two groups. Students enrolled in an academic pattern (college or university preparatory) scored significantly higher on the business attitude questionnaire than did business education students. Business and general education students' scores were not significantly different. Senior high school academic students' levels of occupational aspiration were significantly higher than those of business and general education students. However, the occupational aspirations of students in the business educa-pattern were not significantly higher than those of general education students. This study found a significant correlation between a senior high school students's concept of self (the strength of his feelings about his ability, chances of getting ahead, value of education and educational aspirations) and his level of occupational aspiration. A student's concept of self and attitudes toward business scores were not significantly correlated. Senior high school students' scholastic achievement (grade 11 scholastic average) was found to be significantly correlated with their levels of occupational aspiration. Their attitudes toward business scores, meanwhile, were not significantly correlated with their level of occupational aspiration at any of the four levels of intelligence (IQ). Nor was there a significant correlation between student attitudes toward business and scholastic achievement. Twenty-eight per cent of the students tested indicated that their parents were the greatest single influence on their educational aspirations and 43 per cent indicated that they made their own educational decisions. Academic students did, however, cite their parents as being the most influential factor significantly more often than did non-academic students. Over 60 per cent of the students reported that they made their own occupational decisions, while 10 per cent regarded their parents as being the greatest single influence on their occupational decisions. Academic students reported that their parents were more instrumental in their decisions than did non-academic students. Six per cent of the academic students and 25 per cent of the business and general education students felt that circumstances such as grades, attendance record, and interests were responsible for their choice of a high school educational program. Thirty per cent of the business education students reported that the most important consideration in their choice of an occupation was money, while 20 per cent of the academic and general education students chose money as the most important consideration. On the average, the educational aspiration of the group tested was slightly higher than a baccalaureate degree; the educational aspiration of the academic group was significantly higher than that of the other two groups. The realistic long-range occupational aspirations of the group were significantly higher than their short-range realistic aspirations, and their long-range idealistic occupational aspirations were significantly higher than their short-range idealistic occupational aspirations. Close

• 709. [Article] The common professional education competencies of junior high school teachers

  The central purposes of this study were to identify the common professional education competencies of junior high school teachers and to 1. Determine the proficiency levels necessary in order to accomplish ...

  Citation × Citation Citation Abstract Copy Title: The common professional education competencies of junior high school teachers Author: Gardner, Richard Earl The central purposes of this study were to identify the common professional education competencies of junior high school teachers and to 1. Determine the proficiency levels necessary in order to accomplish these tasks. 2. Determine the cognitive domain levels required in order to fulfill these tasks. The major dimensions of the study were the construction and validation of an interview questionnaire for junior high school teachers, the analysis of variance to determine if there were differences among the junior high schools in their responses to the items, a factor analysis of the competencies and junior high school respondents, a determination of the correlation coefficient between the two sets of dependent variables, and the formulation of implications to be considered in the development of teacher education curricula. The construction of the teacher questionnaire was validated through a review of the literature, an evaluation by a jury panel of experts, and a field test. An interview questionnaire containing 89 professional education competencies, together with a five-point Likert-type scale to denote the required proficiency and a five-point hierarchical scale to denote the necessary cognitive domain level was used to gather data. A random sample of 21 teachers from each of four selected junior high schools in Oregon provided the data for the study. The dependent variables were the scores judgmentally assigned by the respondents to denote the level of proficiency and the cognitive domain level which they felt they possessed for each of the 89 competencies. Analysis of the data revealed that a group of common professional education competencies for junior high school teachers exists and is identifiable. Generally, junior high schools were alike in their responses to the proficiency levels required and the cognitive domain levels necessary in the performance of the identified competencies. Competencies which clustered under the Instruction Factor were judged by teachers to require the highest level of proficiency and the highest cognitive level. Community Relations competencies received the lowest mean and median scores. Generally, those competencies which were identified with the teaching-learning process received higher mean and median values. The further removed the competency was from the actual teaching process, the lower the proficiency requirement and the lower the cognitive requirement. Respondents indicated that moderate, considerable, or complete proficiency, was required with 71 of the 89 competencies and that the cognitive application level or higher was required for 75 of the 89 competencies. The factor analysis techniques revealed that junior high school teachers resembled one another in their responses and demonstrated that it is possible to generate factors containing clusters of common professional education competencies. Title: The common professional education competencies of junior high school teachers Author: Gardner, Richard Earl The central purposes of this study were to identify the common professional education competencies of junior high school teachers and to 1. Determine the proficiency levels necessary in order to accomplish these tasks. 2. Determine the cognitive domain levels required in order to fulfill these tasks. The major dimensions of the study were the construction and validation of an interview questionnaire for junior high school teachers, the analysis of variance to determine if there were differences among the junior high schools in their responses to the items, a factor analysis of the competencies and junior high school respondents, a determination of the correlation coefficient between the two sets of dependent variables, and the formulation of implications to be considered in the development of teacher education curricula. The construction of the teacher questionnaire was validated through a review of the literature, an evaluation by a jury panel of experts, and a field test. An interview questionnaire containing 89 professional education competencies, together with a five-point Likert-type scale to denote the required proficiency and a five-point hierarchical scale to denote the necessary cognitive domain level was used to gather data. A random sample of 21 teachers from each of four selected junior high schools in Oregon provided the data for the study. The dependent variables were the scores judgmentally assigned by the respondents to denote the level of proficiency and the cognitive domain level which they felt they possessed for each of the 89 competencies. Analysis of the data revealed that a group of common professional education competencies for junior high school teachers exists and is identifiable. Generally, junior high schools were alike in their responses to the proficiency levels required and the cognitive domain levels necessary in the performance of the identified competencies. Competencies which clustered under the Instruction Factor were judged by teachers to require the highest level of proficiency and the highest cognitive level. Community Relations competencies received the lowest mean and median scores. Generally, those competencies which were identified with the teaching-learning process received higher mean and median values. The further removed the competency was from the actual teaching process, the lower the proficiency requirement and the lower the cognitive requirement. Respondents indicated that moderate, considerable, or complete proficiency, was required with 71 of the 89 competencies and that the cognitive application level or higher was required for 75 of the 89 competencies. The factor analysis techniques revealed that junior high school teachers resembled one another in their responses and demonstrated that it is possible to generate factors containing clusters of common professional education competencies. Close

• 710. [Article] Predicting logging debris accumulation in natural streambeds : a method for forest managers

  This study has analyzed factors which affect the accumulation of terrestrial organic debris within natural gravel streambeds. In addition, the amounts, sizes, and physical conditions of intruded material ...

  Citation × Citation Citation Abstract Copy Title: Predicting logging debris accumulation in natural streambeds : a method for forest managers Author: Hess, Vernon Scott This study has analyzed factors which affect the accumulation of terrestrial organic debris within natural gravel streambeds. In addition, the amounts, sizes, and physical conditions of intruded material were measured, along with the effect of the detritus on intragravel dissolved oxygen levels. Measurements indicate that aged intragravel detritus had no significant impact on subsurface dissolved oxygen levels. The organic material extracted from the streambeds was composed primarily of highly conditioned woody material, which is characterized by a very low B.O.D. These measurements support the hypothesis that decomposing organic material produces only a temporary demand on intragravel dissolved oxygen supplies. Previous work has indicated that this demand has generally been met after only 60 days. One hundred and forty-four frozen core samples of ten streambeds were taken as a means of analyzing subsurface organic debris concentrations. These cores provided the data needed to calculate streambed porosity, median cobble size, and average detritus size. In addition, stream gradient and surface debris loading were measured. Subsurface organic debris concentrations were found, to be extremely variable. The range of values observed, in grams of detritus per liter of pore volume, was 1.4 to 439.9. The mean value was 29.3 grams per liter of pore volume, with a standard. deviation of 52.9. These values indicate that organic material may provide a severe threat to subsurface dissolved oxygen levels, especially if high concentrations of fresh, finely divided material, such as leaves or needles, are present. Although the impacts exerted by organic material are only temporary, there may be a detrimental impact on the fisheries resource, if a large B.O.D. is produced at the time alevins are dependent on intragravel dissolved oxygen. Regression equations for predicting subsurface debris concentrations were developed. It was observed That subsurface debris accumulations can generally be expected to increase with increases in streambed porosity, surface debris loading, and median cobble size. Concentrations can be expected to decrease with increases in stream gradient. Estimates developed with these models cannot be expected to yield accurate values under all conditions, and the possibility of high variability must be anticipated. However, the models developed in this study do provide a means of predicting subsurface debris accumulations in natural gravel streambeds under a variety of conditions. In addition, the measurement and analysis techniques described will encourage future research which will further develop an understanding of the small stream ecosystem. Title: Predicting logging debris accumulation in natural streambeds : a method for forest managers Author: Hess, Vernon Scott This study has analyzed factors which affect the accumulation of terrestrial organic debris within natural gravel streambeds. In addition, the amounts, sizes, and physical conditions of intruded material were measured, along with the effect of the detritus on intragravel dissolved oxygen levels. Measurements indicate that aged intragravel detritus had no significant impact on subsurface dissolved oxygen levels. The organic material extracted from the streambeds was composed primarily of highly conditioned woody material, which is characterized by a very low B.O.D. These measurements support the hypothesis that decomposing organic material produces only a temporary demand on intragravel dissolved oxygen supplies. Previous work has indicated that this demand has generally been met after only 60 days. One hundred and forty-four frozen core samples of ten streambeds were taken as a means of analyzing subsurface organic debris concentrations. These cores provided the data needed to calculate streambed porosity, median cobble size, and average detritus size. In addition, stream gradient and surface debris loading were measured. Subsurface organic debris concentrations were found, to be extremely variable. The range of values observed, in grams of detritus per liter of pore volume, was 1.4 to 439.9. The mean value was 29.3 grams per liter of pore volume, with a standard. deviation of 52.9. These values indicate that organic material may provide a severe threat to subsurface dissolved oxygen levels, especially if high concentrations of fresh, finely divided material, such as leaves or needles, are present. Although the impacts exerted by organic material are only temporary, there may be a detrimental impact on the fisheries resource, if a large B.O.D. is produced at the time alevins are dependent on intragravel dissolved oxygen. Regression equations for predicting subsurface debris concentrations were developed. It was observed That subsurface debris accumulations can generally be expected to increase with increases in streambed porosity, surface debris loading, and median cobble size. Concentrations can be expected to decrease with increases in stream gradient. Estimates developed with these models cannot be expected to yield accurate values under all conditions, and the possibility of high variability must be anticipated. However, the models developed in this study do provide a means of predicting subsurface debris accumulations in natural gravel streambeds under a variety of conditions. In addition, the measurement and analysis techniques described will encourage future research which will further develop an understanding of the small stream ecosystem. Close