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• 1411. [Article] A study of methods of parental evaluation using testers to predict subsequent progeny performance in winter wheat (Triticum aestivum L.)

  The major objective of this study was to determine why certain winter wheat cultivars, when hybridized, will produce a greater proportion of desirable plants in subsequent, segregating generations. Three ...

  Citation × Citation Citation Abstract Copy Title: A study of methods of parental evaluation using testers to predict subsequent progeny performance in winter wheat (Triticum aestivum L.) Author: Alexander, William Larry The major objective of this study was to determine why certain winter wheat cultivars, when hybridized, will produce a greater proportion of desirable plants in subsequent, segregating generations. Three winter wheat parents were chosen as the experimental material, based on their known performance as parents. Yamhill and Pullman Selection 101 are recognized as cultivars with good combining abilities for grain yield. Crosses with Nugaines have been disappointing, even though the cultivar itself is high yielding. Each parent was crossed to a series of five testers. These testers were chosen on the basis of their genetic diversity, especially for the components of yield. This parent x tester crossing scheme was analyzed as a 3 x 5 factorial, where the main effects due to parents and testers were their general combining ability effect estimates. The interactions of these main effects were their specific combining abilities. F₁ hybrids were evaluated for two years and F₂ populations for one year to characterize the parents' capacity to transmit selected attributes to their resulting progeny. These generations were evaluated on a per plant basis for their grain yields and the primary components of yield, tillers per plant, kernels per spike, and 1000 kernel weight. The four methods of evaluating parents assessed were parental performance, midparent-progeny correlations, examination of individual crosses, and combining ability analysis. Midparent-progeny correlations usually were not significant within the progeny of each parent. Significant differences were not found for grain yields among the parents in either year. However, significant differences existed for their expressions of yield components. Parental expressions of the yield components were generally more erratic than those of their F₁ progenies. Significant differences occurred for estimates of general combining ability effects in both years and for each generation in all traits. These estimates for a particular parent were relatively consistent. Specific combining ability was not found to be a dependable means of identifying superior combinations. Associations between the parental general combining ability effect estimates for kernels per spike and 1000 kernel weight were positive. Relationships between other yield component combinations were negative with regard to general combining ability effects. Trends observed in single crosses reflected the relative general combining abilities of the parents. Crosses involving Yamhill generally had fewer tillers with a higher number of kernels per spike, heavier kernel weights, and superior grain yields to those of the other parents. Progeny of Pullman Selection 101 were usually high in tillering, intermediate for number of kernels per spike, low in kernel weights, and intermediate for grain yields. The progeny of Nugaines were characterized by high tillering, a low number of kernels per spike, low kernel weights, and also low grain yields. The parent x tester crossing scheme was found to be an effective way of determining the potentials of the three parents by estimating their general combining abilities, as well as minimizing the number of crosses required. If, as found in this study, the general combining ability effect estimates of the parents for grain yield accurately predict performance of later generations, this parent x tester crossing scheme would be an efficient method of assessing the potentials of prospective parents in breeding programs. Title: A study of methods of parental evaluation using testers to predict subsequent progeny performance in winter wheat (Triticum aestivum L.) Author: Alexander, William Larry The major objective of this study was to determine why certain winter wheat cultivars, when hybridized, will produce a greater proportion of desirable plants in subsequent, segregating generations. Three winter wheat parents were chosen as the experimental material, based on their known performance as parents. Yamhill and Pullman Selection 101 are recognized as cultivars with good combining abilities for grain yield. Crosses with Nugaines have been disappointing, even though the cultivar itself is high yielding. Each parent was crossed to a series of five testers. These testers were chosen on the basis of their genetic diversity, especially for the components of yield. This parent x tester crossing scheme was analyzed as a 3 x 5 factorial, where the main effects due to parents and testers were their general combining ability effect estimates. The interactions of these main effects were their specific combining abilities. F₁ hybrids were evaluated for two years and F₂ populations for one year to characterize the parents' capacity to transmit selected attributes to their resulting progeny. These generations were evaluated on a per plant basis for their grain yields and the primary components of yield, tillers per plant, kernels per spike, and 1000 kernel weight. The four methods of evaluating parents assessed were parental performance, midparent-progeny correlations, examination of individual crosses, and combining ability analysis. Midparent-progeny correlations usually were not significant within the progeny of each parent. Significant differences were not found for grain yields among the parents in either year. However, significant differences existed for their expressions of yield components. Parental expressions of the yield components were generally more erratic than those of their F₁ progenies. Significant differences occurred for estimates of general combining ability effects in both years and for each generation in all traits. These estimates for a particular parent were relatively consistent. Specific combining ability was not found to be a dependable means of identifying superior combinations. Associations between the parental general combining ability effect estimates for kernels per spike and 1000 kernel weight were positive. Relationships between other yield component combinations were negative with regard to general combining ability effects. Trends observed in single crosses reflected the relative general combining abilities of the parents. Crosses involving Yamhill generally had fewer tillers with a higher number of kernels per spike, heavier kernel weights, and superior grain yields to those of the other parents. Progeny of Pullman Selection 101 were usually high in tillering, intermediate for number of kernels per spike, low in kernel weights, and intermediate for grain yields. The progeny of Nugaines were characterized by high tillering, a low number of kernels per spike, low kernel weights, and also low grain yields. The parent x tester crossing scheme was found to be an effective way of determining the potentials of the three parents by estimating their general combining abilities, as well as minimizing the number of crosses required. If, as found in this study, the general combining ability effect estimates of the parents for grain yield accurately predict performance of later generations, this parent x tester crossing scheme would be an efficient method of assessing the potentials of prospective parents in breeding programs. Close

• 1412. [Article] The effects of sociological theories of poverty on job training programs

  This thesis is an exploratory study of the effects of two job training programs for the poor in Portland, Oregon. It seeks to illustrate that training programs are designed around certain theoretical conceptions ...

  Citation × Citation Citation Abstract Copy Title: The effects of sociological theories of poverty on job training programs Author: DeShane, Michael Richard Year: 1971 This thesis is an exploratory study of the effects of two job training programs for the poor in Portland, Oregon. It seeks to illustrate that training programs are designed around certain theoretical conceptions or models of poverty and that these theoretical conceptions ultimately have a strong effect on the enrollees in programs designed on the given theoretical model. Two general theoretical models have been extracted from the literature. The first is the "Culture of Poverty" model and the second may be called the "Closed Opportunity Structure" model. The culture of poverty model posits that the poor are unable to escape poverty because of certain cultural aspects of their conditions which inhibit them from taking advantage of increased opportunities when they are offered them. Some of the major aspects of the culture of poverty are: (1) The poor do not share the values of the dominant culture, e.g., that hard work brings rewards, and deferring immediate gratification also produces future rewards; (2) The poor do not participate fully in the major institutions of the society; (3) The inability to take advantage of increased opportunities is learned through the parents; and (4) This inability tends to perpetuate the culture of poverty. The closed opportunity model, on the other hand, posits that the poor do indeed share the values of the dominant culture but that they have been denied the opportunity to realize these values, i.e., the poor do not defer gratification because even if they did so their chances of receiving a future reward are low. The closed opportunity structure model sees the problems of the poor as being grounded in the larger society as opposed to being inherent deficiencies of the poor themselves. I have selected two programs for this study on the basis of their subscription to one or the other theoretical models discussed above. Portland Residential Manpower Center (PRMC), an urban Job Corps camp, was chosen because its program design conforms to the culture of poverty model in that it attempts to resocialize the trainee so that he may better fit into the society; conversely, the Portland New Careers Project was chosen because it subscribed to the closed opportunity model in that it does not see these socialization attempts as necessary, but rather, it places its trainees in social service positions with various governmental agencies and provides them with education which, hopefully, will enable the trainee to move into a more professional position at the agency. The study then attempts to describe the effects of each of these programs on its enrollees. The method of direct observation was chosen for several reasons: (1) The exploratory nature of the study; (2) The absence of a clear cut hypothesis to test; (3) inadequate statistical data available which would give me answers to the kinds of questions I had asked. The findings indicated that the two programs had very different effects on the enrollees. PRMC, because of its highly structured character and complete program of socialization, produced a high degree of distrust of the program on the part of the trainees. PRMC's socialization attempts were seen as largely unnecessary by the trainees and they felt that these attempts interfered with the primary task of skill training. New Careers, on the other hand, lacks a highly structured program. Aside from being expected to put in time at the placement agency and to attend his classes, the trainee is left largely on his own. This almost complete lack of structure has made it exceedingly difficult for many of the trainees to progress in the program because they have few guidelines for their training. The New Careerist learns what is expected of him through trial and error. The findings of this study suggest that social scientists should be aware of the consequences of their theoretical models on the people these models attempt to deal with. Both programs studies exhibited deficiencies which, in varying degrees, are the result of the theoretical models upon which the program is based. Title: The effects of sociological theories of poverty on job training programs Author: DeShane, Michael Richard Year: 1971 This thesis is an exploratory study of the effects of two job training programs for the poor in Portland, Oregon. It seeks to illustrate that training programs are designed around certain theoretical conceptions or models of poverty and that these theoretical conceptions ultimately have a strong effect on the enrollees in programs designed on the given theoretical model. Two general theoretical models have been extracted from the literature. The first is the "Culture of Poverty" model and the second may be called the "Closed Opportunity Structure" model. The culture of poverty model posits that the poor are unable to escape poverty because of certain cultural aspects of their conditions which inhibit them from taking advantage of increased opportunities when they are offered them. Some of the major aspects of the culture of poverty are: (1) The poor do not share the values of the dominant culture, e.g., that hard work brings rewards, and deferring immediate gratification also produces future rewards; (2) The poor do not participate fully in the major institutions of the society; (3) The inability to take advantage of increased opportunities is learned through the parents; and (4) This inability tends to perpetuate the culture of poverty. The closed opportunity model, on the other hand, posits that the poor do indeed share the values of the dominant culture but that they have been denied the opportunity to realize these values, i.e., the poor do not defer gratification because even if they did so their chances of receiving a future reward are low. The closed opportunity structure model sees the problems of the poor as being grounded in the larger society as opposed to being inherent deficiencies of the poor themselves. I have selected two programs for this study on the basis of their subscription to one or the other theoretical models discussed above. Portland Residential Manpower Center (PRMC), an urban Job Corps camp, was chosen because its program design conforms to the culture of poverty model in that it attempts to resocialize the trainee so that he may better fit into the society; conversely, the Portland New Careers Project was chosen because it subscribed to the closed opportunity model in that it does not see these socialization attempts as necessary, but rather, it places its trainees in social service positions with various governmental agencies and provides them with education which, hopefully, will enable the trainee to move into a more professional position at the agency. The study then attempts to describe the effects of each of these programs on its enrollees. The method of direct observation was chosen for several reasons: (1) The exploratory nature of the study; (2) The absence of a clear cut hypothesis to test; (3) inadequate statistical data available which would give me answers to the kinds of questions I had asked. The findings indicated that the two programs had very different effects on the enrollees. PRMC, because of its highly structured character and complete program of socialization, produced a high degree of distrust of the program on the part of the trainees. PRMC's socialization attempts were seen as largely unnecessary by the trainees and they felt that these attempts interfered with the primary task of skill training. New Careers, on the other hand, lacks a highly structured program. Aside from being expected to put in time at the placement agency and to attend his classes, the trainee is left largely on his own. This almost complete lack of structure has made it exceedingly difficult for many of the trainees to progress in the program because they have few guidelines for their training. The New Careerist learns what is expected of him through trial and error. The findings of this study suggest that social scientists should be aware of the consequences of their theoretical models on the people these models attempt to deal with. Both programs studies exhibited deficiencies which, in varying degrees, are the result of the theoretical models upon which the program is based. Close

• 1413. [Article] Taste responses in sheep

  This study involved the use of the two-choice preference test, where the choices were tap water and tap water-chemical solutions, to determine the responses of sheep to ascending concentrations of 20 chemicals ...

  Citation × Citation Citation Abstract Copy Title: Taste responses in sheep Author: Goatcher, William Donald This study involved the use of the two-choice preference test, where the choices were tap water and tap water-chemical solutions, to determine the responses of sheep to ascending concentrations of 20 chemicals (taste stimulants). The chemicals tested were: the sugars, sucrose, maltose, lactose, glucose, fructose and galactose; the sodium salts of chloride, acetate (NaAc), propionate (NaPr) and butyrate (NaBu); the acids, hydrochloric, acetic (HAc), propionic (HPr), butyric (HBu) and lactic (HLa); and, quinine hydrochloride (QHC1), urea, sodium saccharin, sodium hydroxide and ethanol. Each sheep was individually penned and fed to appetite. Responses were expressed on the basis of percent intake (that is, the percent that the amount of test fluid consumed was of total fluid intake for a given time period). Three groups of ten sheep. each were used successively, the groups being divided into two units of five animals and these units then being placed on alternate concentrations of a test chemical. The mean responses of the units of five sheep were plotted graphically and analyzed by the linear regression technique when definite rejection trends were apparent. The chemical concentrations at the acceptance and rejection thresholds (that is, where the test chemical comprised 40% and 20% of total fluid intake, respectively) were estimated from the regression line. When rejection trends did not occur the responses were assessed on the basis of their position relative to the non-discrimination zone. The nondiscrimination zone was described as that zone where the test fluid comprised not less than 40% nor more than 60% of total fluid intake. It was derived by determining the normal variation, with tap water in both containers, around a theoretical mean intake of 50% from each container. The responses to the sugars were, generally, of an indifferent nature. One unit of animals displayed a. moderately strong preference (79. 2% of intake) for sucrose at the . 1461 M concentration while another unit was indifferent to the sugar at that concentration. A weak preference (69.0% of intake) occurred for glucose at the . 2775 M concentration. These were the only positive preferences observed for any of the test chemicals. Moderate degrees of rejection were manifested for sucrose concentrations above . 4382.M and for maltose concentrations above. 0028 M. The pattern of the responses to sodium saccharin was similar to that of the sugars: indifference at lower and intermediate concentrations and moderate degrees of rejection at higher concentrations. The acceptance and rejection thresholds for NaC1 were at concentrations of . 0429 M and . 3764 M, respectively. The thresholds for NaAc were similar to those for NaC1. NaPr and NaBu had lower threshold concentrations than NaCl and NaAc-.-possibly because of smell. The threshold concentrations and pH's obtained for HAc were: acceptance, . 0024 M, pH of 4. 2; rejection, . 0276 M, pH of 3. 4. The thresholds for HC1 were at lower concentrations and lower pH's than for HAc. HPr and HBu were discriminated against at lower concentrations and higher pH's than was HAc--possibly due 'to smell. The concentrations at the acceptance and rejection thresholds of NaOH were, respectively, .0036 M ('pH 11. 5) and .0132 M (pH 12. 0). A comparison of these values with those for HC1 indicates that sheep are more tolerant of highly alkaline pH's than of highly acid pH's. QHC1 elicited acceptance and rejection threshold concentrations of. 00048 M and . 0037 M, respectively. The responses to urea were highly variable, but appreciable intake was observed at concentrations of .4163 and 8325 M, The thresholds for ethyl alcohol were at higher concentrations than for any other of the test chemicals, sucrose and glucose being the exceptions. The acceptance threshold for ethanol was at a concentration of. 2621 M and the rejection threshold was at 1. 422 M. With respect to glucose, NaC1, HAc and QHC1, the sensitivity series for the four primary taste groups, in order of increasing sensitivity, was: sweet, salty, sour and bitter. However, after comparing the threshold values derived in this study for the sheep to values reported for the goat and calf, the conclusions can be made that the sheep is relatively indifferent to sweet tasting substances and relatively tolerant to bitter tasting substances. Considerable individual variation existed in the taste responses exhibited by the sheep used in this study. Title: Taste responses in sheep Author: Goatcher, William Donald This study involved the use of the two-choice preference test, where the choices were tap water and tap water-chemical solutions, to determine the responses of sheep to ascending concentrations of 20 chemicals (taste stimulants). The chemicals tested were: the sugars, sucrose, maltose, lactose, glucose, fructose and galactose; the sodium salts of chloride, acetate (NaAc), propionate (NaPr) and butyrate (NaBu); the acids, hydrochloric, acetic (HAc), propionic (HPr), butyric (HBu) and lactic (HLa); and, quinine hydrochloride (QHC1), urea, sodium saccharin, sodium hydroxide and ethanol. Each sheep was individually penned and fed to appetite. Responses were expressed on the basis of percent intake (that is, the percent that the amount of test fluid consumed was of total fluid intake for a given time period). Three groups of ten sheep. each were used successively, the groups being divided into two units of five animals and these units then being placed on alternate concentrations of a test chemical. The mean responses of the units of five sheep were plotted graphically and analyzed by the linear regression technique when definite rejection trends were apparent. The chemical concentrations at the acceptance and rejection thresholds (that is, where the test chemical comprised 40% and 20% of total fluid intake, respectively) were estimated from the regression line. When rejection trends did not occur the responses were assessed on the basis of their position relative to the non-discrimination zone. The nondiscrimination zone was described as that zone where the test fluid comprised not less than 40% nor more than 60% of total fluid intake. It was derived by determining the normal variation, with tap water in both containers, around a theoretical mean intake of 50% from each container. The responses to the sugars were, generally, of an indifferent nature. One unit of animals displayed a. moderately strong preference (79. 2% of intake) for sucrose at the . 1461 M concentration while another unit was indifferent to the sugar at that concentration. A weak preference (69.0% of intake) occurred for glucose at the . 2775 M concentration. These were the only positive preferences observed for any of the test chemicals. Moderate degrees of rejection were manifested for sucrose concentrations above . 4382.M and for maltose concentrations above. 0028 M. The pattern of the responses to sodium saccharin was similar to that of the sugars: indifference at lower and intermediate concentrations and moderate degrees of rejection at higher concentrations. The acceptance and rejection thresholds for NaC1 were at concentrations of . 0429 M and . 3764 M, respectively. The thresholds for NaAc were similar to those for NaC1. NaPr and NaBu had lower threshold concentrations than NaCl and NaAc-.-possibly because of smell. The threshold concentrations and pH's obtained for HAc were: acceptance, . 0024 M, pH of 4. 2; rejection, . 0276 M, pH of 3. 4. The thresholds for HC1 were at lower concentrations and lower pH's than for HAc. HPr and HBu were discriminated against at lower concentrations and higher pH's than was HAc--possibly due 'to smell. The concentrations at the acceptance and rejection thresholds of NaOH were, respectively, .0036 M ('pH 11. 5) and .0132 M (pH 12. 0). A comparison of these values with those for HC1 indicates that sheep are more tolerant of highly alkaline pH's than of highly acid pH's. QHC1 elicited acceptance and rejection threshold concentrations of. 00048 M and . 0037 M, respectively. The responses to urea were highly variable, but appreciable intake was observed at concentrations of .4163 and 8325 M, The thresholds for ethyl alcohol were at higher concentrations than for any other of the test chemicals, sucrose and glucose being the exceptions. The acceptance threshold for ethanol was at a concentration of. 2621 M and the rejection threshold was at 1. 422 M. With respect to glucose, NaC1, HAc and QHC1, the sensitivity series for the four primary taste groups, in order of increasing sensitivity, was: sweet, salty, sour and bitter. However, after comparing the threshold values derived in this study for the sheep to values reported for the goat and calf, the conclusions can be made that the sheep is relatively indifferent to sweet tasting substances and relatively tolerant to bitter tasting substances. Considerable individual variation existed in the taste responses exhibited by the sheep used in this study. Close

• 1414. [Article] Measurement, modeling, and remote sensing of snow cover in areas of heterogeneous vegetation

  Numerous studies have demonstrated that vegetation canopies affect snow accumulation and ablation processes. In addition, estimates of remotely sensed snow covered area can be biased by the presence of ...

  Citation × Citation Citation Abstract Copy Title: Measurement, modeling, and remote sensing of snow cover in areas of heterogeneous vegetation Author: Selkowitz, David Numerous studies have demonstrated that vegetation canopies affect snow accumulation and ablation processes. In addition, estimates of remotely sensed snow covered area can be biased by the presence of an overlying vegetation canopy. Consequently, any attempts to measure, model, or map the distribution of snow in a region with heterogeneous vegetation cover would benefit from a more complete understanding of both the relationship between vegetation density and snow cover on the ground as well as the relationship between remotely sensed snow covered area and actual snow covered area under various vegetation densities. The research presented here explores both of these relationships. Chapter 2 describes, qualitatively and quantitatively, the relationship between canopy gap fraction (the inverse of canopy density) and snow accumulation at fine spatial scales in Glacier National Park, Montana. Gap fraction and snow cover data from two winters were compared along eight vegetation-snow transects representing a range of landscape types, including dense forest, variable density forests with openings, forest-grassland mosaics, and burned-unburned forest mosaics. The data suggest that the relationship between gap fraction and snow accumulation depends on the range of gap fraction values considered. For gap fraction values less than 40%, a significant positive linear relationship exists between gap fraction and snow accumulation. For gap fraction values between 40% and 90%, the relationship is poorly defined, most likely due to the influence of the spatial patterning of vegetation on wind scouring/deposition of snow which cannot be captured by a simple metric such as gap fraction. When gap fraction exceeds - 90%, snow cover is almost always shallow or nonexistent due to wind scouring and high solar radiation loads. The poorly defined relationship between gap fraction and snow accumulation in the range of 40-90% gap fraction is not highly problematic because this gap fraction range represents only 24% of the landscape, and the 60-90% range of gap fraction where the gap fraction-snow accumulation relationship is least pronounced represents only 5% of the landscape. The results from these vegetation-snow surveys indicate that at fine spatial scales where topographic variability is minimal, canopy density can explain a substantial portion of the variability in snow accumulation that would otherwise remain unexplained. The high variance in snow accumulation in the 60-90% gap fraction range and the relatively small sample size presented here make it unrealistic, however, to infer an optimum gap fraction for snow accumulation in Glacier National Park or anywhere else. Chapter 3 provides an assessment of methods for modeling and mapping spatiotemporal variability in snow cover in Glacier National Park. SnowModel, a relatively new physically-based snow evolution model that accounts for the influence of vegetation on snow processes, was used to simulate the spatial distribution of snow water equivalent at hourly time steps for an 850 km2 model domain in eastern Glacier National Park. The standard implementation of SnowModel uses an image of land cover type to adjust snow accumulation and ablation for the effects of vegetation. In this non-standard implementation, the model was parameterized using a weighting scheme that allowed the model to utilize a Landsat-derived image of gap fraction to adjust snow accumulation and ablation in a more precise manner than would have been possible if only land cover type information was available. In situ measurements suggest the model did a reasonable job simulating snow evolution patterns and the differences in snow evolution associated with different vegetation densities. Weaknesses in this implementation of SnowModel appear to be its tendency to overestimate snow in the easternmost portion of the model domain (where a significant rain shadow effect exists) and overestimate snow in exposed areas. Due to a lack of in situ measurements at the scale of the model output, it was not possible to conclusively determine if the incorporation of fine scale (28.5 m pixel) information on forest canopy density improved model accuracy. MODIS-derived images of binary and fractional snow covered area were also evaluated. The binary product consistently mapped a higher percentage of the study area as snow covered than the fractional product. Spatial patterns of snow covered area were similar for the MODIS-derived products and the results from the implementation of SnowModel. Unfortunately, the remotely sensed snow covered area products could not be used to evaluate the model's treatment of snow evolution under different vegetation conditions because gap fraction influences the mapping of snow covered area for the remotely sensed products. Understanding how remotely sensed estimates of snow covered area are influenced by gap fraction density will hopefully allow for these products to be used as a validation tool for spatially distributed model results in areas of heterogeneous vegetation in the future. Title: Measurement, modeling, and remote sensing of snow cover in areas of heterogeneous vegetation Author: Selkowitz, David Numerous studies have demonstrated that vegetation canopies affect snow accumulation and ablation processes. In addition, estimates of remotely sensed snow covered area can be biased by the presence of an overlying vegetation canopy. Consequently, any attempts to measure, model, or map the distribution of snow in a region with heterogeneous vegetation cover would benefit from a more complete understanding of both the relationship between vegetation density and snow cover on the ground as well as the relationship between remotely sensed snow covered area and actual snow covered area under various vegetation densities. The research presented here explores both of these relationships. Chapter 2 describes, qualitatively and quantitatively, the relationship between canopy gap fraction (the inverse of canopy density) and snow accumulation at fine spatial scales in Glacier National Park, Montana. Gap fraction and snow cover data from two winters were compared along eight vegetation-snow transects representing a range of landscape types, including dense forest, variable density forests with openings, forest-grassland mosaics, and burned-unburned forest mosaics. The data suggest that the relationship between gap fraction and snow accumulation depends on the range of gap fraction values considered. For gap fraction values less than 40%, a significant positive linear relationship exists between gap fraction and snow accumulation. For gap fraction values between 40% and 90%, the relationship is poorly defined, most likely due to the influence of the spatial patterning of vegetation on wind scouring/deposition of snow which cannot be captured by a simple metric such as gap fraction. When gap fraction exceeds - 90%, snow cover is almost always shallow or nonexistent due to wind scouring and high solar radiation loads. The poorly defined relationship between gap fraction and snow accumulation in the range of 40-90% gap fraction is not highly problematic because this gap fraction range represents only 24% of the landscape, and the 60-90% range of gap fraction where the gap fraction-snow accumulation relationship is least pronounced represents only 5% of the landscape. The results from these vegetation-snow surveys indicate that at fine spatial scales where topographic variability is minimal, canopy density can explain a substantial portion of the variability in snow accumulation that would otherwise remain unexplained. The high variance in snow accumulation in the 60-90% gap fraction range and the relatively small sample size presented here make it unrealistic, however, to infer an optimum gap fraction for snow accumulation in Glacier National Park or anywhere else. Chapter 3 provides an assessment of methods for modeling and mapping spatiotemporal variability in snow cover in Glacier National Park. SnowModel, a relatively new physically-based snow evolution model that accounts for the influence of vegetation on snow processes, was used to simulate the spatial distribution of snow water equivalent at hourly time steps for an 850 km2 model domain in eastern Glacier National Park. The standard implementation of SnowModel uses an image of land cover type to adjust snow accumulation and ablation for the effects of vegetation. In this non-standard implementation, the model was parameterized using a weighting scheme that allowed the model to utilize a Landsat-derived image of gap fraction to adjust snow accumulation and ablation in a more precise manner than would have been possible if only land cover type information was available. In situ measurements suggest the model did a reasonable job simulating snow evolution patterns and the differences in snow evolution associated with different vegetation densities. Weaknesses in this implementation of SnowModel appear to be its tendency to overestimate snow in the easternmost portion of the model domain (where a significant rain shadow effect exists) and overestimate snow in exposed areas. Due to a lack of in situ measurements at the scale of the model output, it was not possible to conclusively determine if the incorporation of fine scale (28.5 m pixel) information on forest canopy density improved model accuracy. MODIS-derived images of binary and fractional snow covered area were also evaluated. The binary product consistently mapped a higher percentage of the study area as snow covered than the fractional product. Spatial patterns of snow covered area were similar for the MODIS-derived products and the results from the implementation of SnowModel. Unfortunately, the remotely sensed snow covered area products could not be used to evaluate the model's treatment of snow evolution under different vegetation conditions because gap fraction influences the mapping of snow covered area for the remotely sensed products. Understanding how remotely sensed estimates of snow covered area are influenced by gap fraction density will hopefully allow for these products to be used as a validation tool for spatially distributed model results in areas of heterogeneous vegetation in the future. Close

• 1415. [Article] CO₂ Reduction in Microscale-Based Corona Reactor : Experiments and Modeling

  Global warming is becoming an increasingly important environmental concern and CO₂ is considered as the major cause of global warming. Creating useful applications for CO₂ would generate alternatives to ...

  Citation × Citation Citation Abstract Copy Title: CO₂ Reduction in Microscale-Based Corona Reactor : Experiments and Modeling Author: Miao, Yu Global warming is becoming an increasingly important environmental concern and CO₂ is considered as the major cause of global warming. Creating useful applications for CO₂ would generate alternatives to merely venting CO₂ to the atmosphere, and decreasing the carbon intensity of human activities. Among various methods of CO₂ utilization, conversion of CO₂ to value-added chemical products is the most attractive. In this study, microtechnology and application of corona discharge are combined and introduced into CO₂ reduction process. Experiments were conducted before the design and manufacture of the microreactor to determine the configuration of the reactor, products of reaction and effect of active volume ratio: (1) it is proved that through-gas corona discharge are much simpler to implement than through-liquid, especially those with high solubility of CO₂; (2) the V-I curve for the corona discharge reactors is characterized by a transition from a high voltage low current (which we call spark discharge) to a low voltage high current state (the corona discharge state), with this transition used as a diagnostic of the reactor operation in the corona discharge mode even when direct observation of the discharge is not practical; (3) the products for the reduction of dry CO₂ are carbon monoxide (CO) and oxygen (O₂), while for the reduction of wet CO₂, methane (CH4) is also formed in addition to these two products; (4) a larger active volume ratio results in higher conversion of CO₂ to products. Based on the experimental results listed above, two multi-discharge microscale-based corona reactors were designed and manufactured. We found that for a needle-to-plate gap of 110μm, at the voltage of 0.840kV and current of 0.62mA, a flow of CO₂ and H₂O mixture (flow rate of CO₂ = 50sccm, CO₂-to-H₂O molar ratio = 1:2) can result in 5.5~6% conversion of CO₂ (with 40~50% conversion within the active volume of the reactor) with energy efficiency of 85~95%. The influence of the three main factors, namely the power applied to the reactor (specific points of the V-I curve used), flow rate of CO₂, and CO₂-to-H₂O molar ratio, on the performance and energy efficiency of the reactor were investigated. It was found that (1) the glow regime (or corona regime) is the optimal operation regime for this process from both conversion and energy efficiency perspectives, with higher current in this regime resulting in higher CO₂ conversion; (2) lower flow rate of CO₂ can result in higher conversion with lower energy efficiency, and conversely, the highest energy efficiency is achieved at the highest flow rate; (3) the conversion of CO₂ increases as the CO₂-to-H₂O molar ratio decreases, but the highest energy efficiency is achieved when this ratio matches the ratio of stoichiometric numbers. A numerical model of the process reflecting the geometry, momentum balance, material balance and kinetics inside the reactor was developed to help understand the chemical reaction process. The reaction scheme was modelled as being driven by the initial cleavage of a CO₂ or H₂O molecule caused by collision with energetic electrons to produce CO+O or OH+H, followed by cascaded spontaneous reactions that yield the products. The reaction kinetics were approached as following pseudo-Arrhenius laws with a pre-exponential term k₀ and an exponential term, but rather than modelling the exponential term as dependent on temperature, the term was modelled as depending on the applied electrical potential in the corona discharge (i.e., rather than dependent on e^(-EA/RT) it was modelled as dependent on e^(-EA/βVF), where β is an effectiveness parameter, V is the applied electrical potential to the discharge, and F is Faraday's constant). A refined parameter n that defines the fraction of CO intermediate that either further fragment or remain as CO in the product stream, termed the kinetic parameter in this work, was also employed. Optimization of the numerical model was applied to extract kinetic parameters for the CO₂ reduction process in the multi-point corona discharge with good agreement between simulated results and experimental data. The values of the final refined parameters were: for the initial dissociation of CO₂, the final values of the refined parameters were k₀,₁ = 3.543±0.071×10¹⁰sec⁻¹ and the electrical potential effectiveness parameter was β₁ = 2.181±0.044×10¹, and for the dissociation of H₂O, the parameters were k₀,₁ = 1.266±0.025×10⁸sec⁻¹, β4 = 8.403±0.168, and the kinetic parameter n = 0.50±0.010. Title: CO₂ Reduction in Microscale-Based Corona Reactor : Experiments and Modeling Author: Miao, Yu Global warming is becoming an increasingly important environmental concern and CO₂ is considered as the major cause of global warming. Creating useful applications for CO₂ would generate alternatives to merely venting CO₂ to the atmosphere, and decreasing the carbon intensity of human activities. Among various methods of CO₂ utilization, conversion of CO₂ to value-added chemical products is the most attractive. In this study, microtechnology and application of corona discharge are combined and introduced into CO₂ reduction process. Experiments were conducted before the design and manufacture of the microreactor to determine the configuration of the reactor, products of reaction and effect of active volume ratio: (1) it is proved that through-gas corona discharge are much simpler to implement than through-liquid, especially those with high solubility of CO₂; (2) the V-I curve for the corona discharge reactors is characterized by a transition from a high voltage low current (which we call spark discharge) to a low voltage high current state (the corona discharge state), with this transition used as a diagnostic of the reactor operation in the corona discharge mode even when direct observation of the discharge is not practical; (3) the products for the reduction of dry CO₂ are carbon monoxide (CO) and oxygen (O₂), while for the reduction of wet CO₂, methane (CH4) is also formed in addition to these two products; (4) a larger active volume ratio results in higher conversion of CO₂ to products. Based on the experimental results listed above, two multi-discharge microscale-based corona reactors were designed and manufactured. We found that for a needle-to-plate gap of 110μm, at the voltage of 0.840kV and current of 0.62mA, a flow of CO₂ and H₂O mixture (flow rate of CO₂ = 50sccm, CO₂-to-H₂O molar ratio = 1:2) can result in 5.5~6% conversion of CO₂ (with 40~50% conversion within the active volume of the reactor) with energy efficiency of 85~95%. The influence of the three main factors, namely the power applied to the reactor (specific points of the V-I curve used), flow rate of CO₂, and CO₂-to-H₂O molar ratio, on the performance and energy efficiency of the reactor were investigated. It was found that (1) the glow regime (or corona regime) is the optimal operation regime for this process from both conversion and energy efficiency perspectives, with higher current in this regime resulting in higher CO₂ conversion; (2) lower flow rate of CO₂ can result in higher conversion with lower energy efficiency, and conversely, the highest energy efficiency is achieved at the highest flow rate; (3) the conversion of CO₂ increases as the CO₂-to-H₂O molar ratio decreases, but the highest energy efficiency is achieved when this ratio matches the ratio of stoichiometric numbers. A numerical model of the process reflecting the geometry, momentum balance, material balance and kinetics inside the reactor was developed to help understand the chemical reaction process. The reaction scheme was modelled as being driven by the initial cleavage of a CO₂ or H₂O molecule caused by collision with energetic electrons to produce CO+O or OH+H, followed by cascaded spontaneous reactions that yield the products. The reaction kinetics were approached as following pseudo-Arrhenius laws with a pre-exponential term k₀ and an exponential term, but rather than modelling the exponential term as dependent on temperature, the term was modelled as depending on the applied electrical potential in the corona discharge (i.e., rather than dependent on e^(-EA/RT) it was modelled as dependent on e^(-EA/βVF), where β is an effectiveness parameter, V is the applied electrical potential to the discharge, and F is Faraday's constant). A refined parameter n that defines the fraction of CO intermediate that either further fragment or remain as CO in the product stream, termed the kinetic parameter in this work, was also employed. Optimization of the numerical model was applied to extract kinetic parameters for the CO₂ reduction process in the multi-point corona discharge with good agreement between simulated results and experimental data. The values of the final refined parameters were: for the initial dissociation of CO₂, the final values of the refined parameters were k₀,₁ = 3.543±0.071×10¹⁰sec⁻¹ and the electrical potential effectiveness parameter was β₁ = 2.181±0.044×10¹, and for the dissociation of H₂O, the parameters were k₀,₁ = 1.266±0.025×10⁸sec⁻¹, β4 = 8.403±0.168, and the kinetic parameter n = 0.50±0.010. Close

• 1416. [Article] Suitability of diverse composts as soil amendments for highbush blueberry (Vaccinium corymbosum L.)

  Highbush blueberry (Vaccinium corymbosum L.) is adapted to soils with high organic matter and acidic pH. Composts provide organic matter and nutrients for growing blueberry in mineral soils, but many ...

  Citation × Citation Citation Abstract Copy Title: Suitability of diverse composts as soil amendments for highbush blueberry (Vaccinium corymbosum L.) Author: Costello, Ryan C. Highbush blueberry (Vaccinium corymbosum L.) is adapted to soils with high organic matter and acidic pH. Composts provide organic matter and nutrients for growing blueberry in mineral soils, but many composts are high in pH and soluble salts. Acidification with elemental sulfur (S°) can remedy high pH, but the process further increases compost salinity. The objectives of this study were to: i) determine the effects of diverse composts on blueberry growth and nutrient uptake, ii) determine whether S° acidification can ameliorate the negative effects of high compost pH, and iii) develop and validate a simple titration method to determine pH buffering capacity of compost. In our first study, ten composts were evaluated under greenhouse conditions with one-year-old blueberry. Each compost was either acidified or not with S° and then mixed 30% by volume with silt loam soil before planting. Controls were sawdust incorporation or soil only. Plants were managed with a low rate of fertilization to emphasize compost effects on nutrient supply. Compost inorganic nitrogen (N) ranged from 0.1 to 4.1 g∙kg⁻¹, and NO₃-N to NH₄-N ratios were greater than 20:1. Aboveground plant growth and nutrient uptake, including N, phosphorous (P), potassium (K), and boron (B) were higher in soil with compost than in soil with sawdust or soil only. Composts with pH < 7.5 produced more shoot growth than those with higher pH, and composts with EC > 2 dS∙m⁻¹ produced less root growth than those with lower EC. Adding S° reduced compost pH by an average of 1.9 units, and acidification increased shoot and root growth in the composts as well as uptake of many nutrients. Plant growth and N uptake were not correlated with compost N supply. Composts with greater amounts of plant-based feedstocks produced more total shoot growth than manure-based composts. In our second study, 3.7 L blueberry transplants were grown outdoors for 119 d in pots containing compost and soil. Manure feedstocks included separated dairy solids or horse stall cleanings. Plant feedstocks included urban yard trimmings, leaves from street sweeping, conifer bark conditioned with municipal biosolids, or peppermint distillation residue. Control treatments were sawdust amendment or soil only. Plant-based compost treatments had less effect on soil pH and produced 20% greater plant growth than manure-based compost treatments. Plant growth was not different with plant-based composts vs. the sawdust amendment control. Elemental S addition at potting did not acidify soil enough to overcome the increase in pH resulting from compost addition. In our third study, we titrated eight composts with dilute H₂SO₄ to predict response to S° acidification. Our objective was to develop and validate a simple method to determine the pH buffering capacity of compost. Compost pH decreased linearly with laboratory acid addition. Compost pH buffering capacity (linear slope of titration curve) was 0.16 to 0.39 mol H⁺ per kg dry compost per pH unit. To determine correlation between titration and S° acidification, composts samples were incubated with S° at 22° C for 70 d. The majority of the decrease in pH from S° addition occurred within 28 d. Compost pH at 28 d was closely predicted by the laboratory titration. Because of the linearity of compost response to acid addition, a 2-point titration method (one rate of acid addition) is an effective alternative to the 7-point method we used. We conclude that compost pH is the primary limiting factor affecting blueberry response to compost. Compost incorporation provided benefit to blueberry, especially under low N management, and generally increased plant growth and nutrient uptake when compared with plants grown in mineral soil only. Composts made from plant-based feedstocks, rather than manure-based feedstocks, tend to have characteristics which favor blueberry growth, including low buffering capacity, pH, and soluble salts. Feedstocks which showed promise include deciduous leaves, yard debris, bark, and horse bedding with low manure content. Acidification of composts with S° increased plant growth and nutrient uptake, and is a promising technology for eliminating the negative effects of high compost pH. Our method of laboratory titration with dilute acid addition was effective in determining pH buffering capacity of compost, and predicted the compost acidification by S° and the effect of compost on soil pH. Title: Suitability of diverse composts as soil amendments for highbush blueberry (Vaccinium corymbosum L.) Author: Costello, Ryan C. Highbush blueberry (Vaccinium corymbosum L.) is adapted to soils with high organic matter and acidic pH. Composts provide organic matter and nutrients for growing blueberry in mineral soils, but many composts are high in pH and soluble salts. Acidification with elemental sulfur (S°) can remedy high pH, but the process further increases compost salinity. The objectives of this study were to: i) determine the effects of diverse composts on blueberry growth and nutrient uptake, ii) determine whether S° acidification can ameliorate the negative effects of high compost pH, and iii) develop and validate a simple titration method to determine pH buffering capacity of compost. In our first study, ten composts were evaluated under greenhouse conditions with one-year-old blueberry. Each compost was either acidified or not with S° and then mixed 30% by volume with silt loam soil before planting. Controls were sawdust incorporation or soil only. Plants were managed with a low rate of fertilization to emphasize compost effects on nutrient supply. Compost inorganic nitrogen (N) ranged from 0.1 to 4.1 g∙kg⁻¹, and NO₃-N to NH₄-N ratios were greater than 20:1. Aboveground plant growth and nutrient uptake, including N, phosphorous (P), potassium (K), and boron (B) were higher in soil with compost than in soil with sawdust or soil only. Composts with pH < 7.5 produced more shoot growth than those with higher pH, and composts with EC > 2 dS∙m⁻¹ produced less root growth than those with lower EC. Adding S° reduced compost pH by an average of 1.9 units, and acidification increased shoot and root growth in the composts as well as uptake of many nutrients. Plant growth and N uptake were not correlated with compost N supply. Composts with greater amounts of plant-based feedstocks produced more total shoot growth than manure-based composts. In our second study, 3.7 L blueberry transplants were grown outdoors for 119 d in pots containing compost and soil. Manure feedstocks included separated dairy solids or horse stall cleanings. Plant feedstocks included urban yard trimmings, leaves from street sweeping, conifer bark conditioned with municipal biosolids, or peppermint distillation residue. Control treatments were sawdust amendment or soil only. Plant-based compost treatments had less effect on soil pH and produced 20% greater plant growth than manure-based compost treatments. Plant growth was not different with plant-based composts vs. the sawdust amendment control. Elemental S addition at potting did not acidify soil enough to overcome the increase in pH resulting from compost addition. In our third study, we titrated eight composts with dilute H₂SO₄ to predict response to S° acidification. Our objective was to develop and validate a simple method to determine the pH buffering capacity of compost. Compost pH decreased linearly with laboratory acid addition. Compost pH buffering capacity (linear slope of titration curve) was 0.16 to 0.39 mol H⁺ per kg dry compost per pH unit. To determine correlation between titration and S° acidification, composts samples were incubated with S° at 22° C for 70 d. The majority of the decrease in pH from S° addition occurred within 28 d. Compost pH at 28 d was closely predicted by the laboratory titration. Because of the linearity of compost response to acid addition, a 2-point titration method (one rate of acid addition) is an effective alternative to the 7-point method we used. We conclude that compost pH is the primary limiting factor affecting blueberry response to compost. Compost incorporation provided benefit to blueberry, especially under low N management, and generally increased plant growth and nutrient uptake when compared with plants grown in mineral soil only. Composts made from plant-based feedstocks, rather than manure-based feedstocks, tend to have characteristics which favor blueberry growth, including low buffering capacity, pH, and soluble salts. Feedstocks which showed promise include deciduous leaves, yard debris, bark, and horse bedding with low manure content. Acidification of composts with S° increased plant growth and nutrient uptake, and is a promising technology for eliminating the negative effects of high compost pH. Our method of laboratory titration with dilute acid addition was effective in determining pH buffering capacity of compost, and predicted the compost acidification by S° and the effect of compost on soil pH. Close

• 1417. [Article] Evolution and inheritance of Cascadia sub-arc mantle reservoirs

  Inheritance from pre-existing mantle domains and fluid and melt contributions from active subduction together produce the geochemical signatures of mantle-derived arc basalts. In this context, this work ...

  Citation × Citation Citation Abstract Copy Title: Evolution and inheritance of Cascadia sub-arc mantle reservoirs Author: Bromley, Sarah Ashley Inheritance from pre-existing mantle domains and fluid and melt contributions from active subduction together produce the geochemical signatures of mantle-derived arc basalts. In this context, this work evaluates the evolution of Cascadia mantle sources by documenting the isotopic and compositional characteristics of primitive basalts along a transect across the Eocene-Oligocene Proto-Cascadia (EOPC) arc at ~44.5-45.5° N. Primitive EOPC flows, dikes, and sills are exposed across a ~300 km transect that includes the Oregon Coast Range in the Cascadia forearc, the Western Cascades, flanking the modern arc, and the John Day and Eastern Clarno formations east of the Cascades. Like the modern arc, EOPC was built upon accreted terranes of western North America and within the Columbia embayment, which is lithosphere of oceanic affinity that crops out as the Siletzia terrane in the forearc and extends beneath the arc to the backarc. Potential mantle source reservoirs for EOPC magmas include contributions from mantle domains related to pre-existing underlying terranes, distinct North America lithosphere, and depleted Pacific-like upper mantle. In addition, the geochemical characteristics of EOPC magmas have likely been overprinted by subduction processes. Major, trace element, and isotopic data from the EOPC reveal a heterogeneous mantle source that was variably influenced by subduction processes. In the forearc, the high field strength (HFSE) enriched basalts of the Oregon Coast Range represent low degree partial melts of a relatively enriched mantle source. Despite this enriched character, there is little evidence in the trace element or isotopic data to suggest that the OCR (Oregon Coast Range) samples have been strongly influenced by either a crustal or subduction component. Their distinctive ²⁰⁶Pb/²⁰⁴Pb enrichment (as compared to ²⁰⁷Pb/²⁰⁴Pb) distinguishes the forearc magmas from the arc and backarc magmas and also from a hypothetical Cascadia subduction component. Forearc EOPC magmas share a mantle source with the accreted Siletzia terrane, as evidenced by their shared ²⁰⁶Pb/²⁰⁴Pb enrichment. At the apparent arc axis, the Western Cascades produced a diversity of primitive magmas that are, for the most part, interpreted to result from higher degrees of partial melting of a less enriched source. Fluid fluxing appears to have facilitated mantle melting beneath the Western Cascades. Additionally, the mantle beneath the arc may be slightly influenced by the ²⁰⁶Pb/²⁰⁴Pb enriched source underlying the forearc. Though this effect is difficult to resolve, the Western Cascades samples appear to be slightly more variable in ²⁰⁶Pb/²⁰⁴Pb (and generally higher in ²⁰⁶Pb/²⁰⁴Pb at a given ²⁰⁷Pb/²⁰⁴Pb) than their backarc counterparts, suggesting such an influence. Both trace element and isotopic data suggest a significant subduction contribution to EOPC backarc primitive magmas. The EOPC backarc magmas appear to have originated from a heterogeneous mantle and are variably influenced by a subduction component. Though this subduction influence could be an inherited feature, the affinity between John Day and Eastern Clarno magmas and a modern Cascadia sediment source suggest that this is at least a relatively young feature. Taken together, these results demonstrate the heterogeneity of source and process across the Eocene-Oligocene arc. Apparent subduction contribution increases from the geographic forearc to backarc, perhaps indicating a wider arc than is typically envisioned at the time. The distinct ²⁰⁶Pb/²⁰⁴Pb enrichment associated with the Siletzia mantle and apparent in the forearc appears to wane in influence to the east, having at most a minor influence on the Western Cascade arc magmas. As with the Siletzia mantle domain in EOPC arc and backarc, mantle domains associated with the Western Cascades and John Day/Eastern Clarno magmas do not persist in the High Cascades or High Lava Plains. Beneath and behind the arc, mantle reservoirs appear to have been largely replaced since the Eocene-Oligocene. However, the High Lava Plains basalts appear to carry a paleo-enrichment signature that may be an inherited feature from advected mantle. If this enriched mantle was advected from beneath North America, it may explain the observation that High Lava Plains basalts are more enriched to the east. Title: Evolution and inheritance of Cascadia sub-arc mantle reservoirs Author: Bromley, Sarah Ashley Inheritance from pre-existing mantle domains and fluid and melt contributions from active subduction together produce the geochemical signatures of mantle-derived arc basalts. In this context, this work evaluates the evolution of Cascadia mantle sources by documenting the isotopic and compositional characteristics of primitive basalts along a transect across the Eocene-Oligocene Proto-Cascadia (EOPC) arc at ~44.5-45.5° N. Primitive EOPC flows, dikes, and sills are exposed across a ~300 km transect that includes the Oregon Coast Range in the Cascadia forearc, the Western Cascades, flanking the modern arc, and the John Day and Eastern Clarno formations east of the Cascades. Like the modern arc, EOPC was built upon accreted terranes of western North America and within the Columbia embayment, which is lithosphere of oceanic affinity that crops out as the Siletzia terrane in the forearc and extends beneath the arc to the backarc. Potential mantle source reservoirs for EOPC magmas include contributions from mantle domains related to pre-existing underlying terranes, distinct North America lithosphere, and depleted Pacific-like upper mantle. In addition, the geochemical characteristics of EOPC magmas have likely been overprinted by subduction processes. Major, trace element, and isotopic data from the EOPC reveal a heterogeneous mantle source that was variably influenced by subduction processes. In the forearc, the high field strength (HFSE) enriched basalts of the Oregon Coast Range represent low degree partial melts of a relatively enriched mantle source. Despite this enriched character, there is little evidence in the trace element or isotopic data to suggest that the OCR (Oregon Coast Range) samples have been strongly influenced by either a crustal or subduction component. Their distinctive ²⁰⁶Pb/²⁰⁴Pb enrichment (as compared to ²⁰⁷Pb/²⁰⁴Pb) distinguishes the forearc magmas from the arc and backarc magmas and also from a hypothetical Cascadia subduction component. Forearc EOPC magmas share a mantle source with the accreted Siletzia terrane, as evidenced by their shared ²⁰⁶Pb/²⁰⁴Pb enrichment. At the apparent arc axis, the Western Cascades produced a diversity of primitive magmas that are, for the most part, interpreted to result from higher degrees of partial melting of a less enriched source. Fluid fluxing appears to have facilitated mantle melting beneath the Western Cascades. Additionally, the mantle beneath the arc may be slightly influenced by the ²⁰⁶Pb/²⁰⁴Pb enriched source underlying the forearc. Though this effect is difficult to resolve, the Western Cascades samples appear to be slightly more variable in ²⁰⁶Pb/²⁰⁴Pb (and generally higher in ²⁰⁶Pb/²⁰⁴Pb at a given ²⁰⁷Pb/²⁰⁴Pb) than their backarc counterparts, suggesting such an influence. Both trace element and isotopic data suggest a significant subduction contribution to EOPC backarc primitive magmas. The EOPC backarc magmas appear to have originated from a heterogeneous mantle and are variably influenced by a subduction component. Though this subduction influence could be an inherited feature, the affinity between John Day and Eastern Clarno magmas and a modern Cascadia sediment source suggest that this is at least a relatively young feature. Taken together, these results demonstrate the heterogeneity of source and process across the Eocene-Oligocene arc. Apparent subduction contribution increases from the geographic forearc to backarc, perhaps indicating a wider arc than is typically envisioned at the time. The distinct ²⁰⁶Pb/²⁰⁴Pb enrichment associated with the Siletzia mantle and apparent in the forearc appears to wane in influence to the east, having at most a minor influence on the Western Cascade arc magmas. As with the Siletzia mantle domain in EOPC arc and backarc, mantle domains associated with the Western Cascades and John Day/Eastern Clarno magmas do not persist in the High Cascades or High Lava Plains. Beneath and behind the arc, mantle reservoirs appear to have been largely replaced since the Eocene-Oligocene. However, the High Lava Plains basalts appear to carry a paleo-enrichment signature that may be an inherited feature from advected mantle. If this enriched mantle was advected from beneath North America, it may explain the observation that High Lava Plains basalts are more enriched to the east. Close

• 1418. [Article] Effects of boron rates and differential irrigation on bush green beans and cauliflower

  Five boron rates and seven water levels were applied to bush green beans (Phaseolus vulqaris cv Oregon 91G) and to cauliflower (Brassica olereacea var. botrytis, cultivar "Snowball Y") in 1989 and 1990 ...

  Citation × Citation Citation Abstract Copy Title: Effects of boron rates and differential irrigation on bush green beans and cauliflower Author: Grealish, William J. Five boron rates and seven water levels were applied to bush green beans (Phaseolus vulqaris cv Oregon 91G) and to cauliflower (Brassica olereacea var. botrytis, cultivar "Snowball Y") in 1989 and 1990 to evaluate their effects on total yield of both crops and on outer quality, head hollowness and internal discoloration of cauliflower curds. Of the five B rates (0,1,3,6 and 9kg/ha) three (0, 3 and 9 kg/ha) were monitored to evaluate B concentrations at soil depths of 0-15, 15-30, 30-45 and 45-60 cm. In each season, B concentrations were analyzed at a high (wet) level of applied water. An overall evaluation comparing the starting and ending levels of B after two years was conducted at two levels of applied water (high and low). Soil applied B rates of 9 kg/ha significantly reduced bean yields in 1989 and 1990. Boron concentrations in the trifoliate leaf tissue at the highest (wet) water level in 1989 and 1990 ranged between 22 to 72 mg/kg for the five B rates. Tissue concentrations at the lowest (dry) Water level in 1990 ranged from 23 to 32 mg/kg B. Soil B levels for both years had an overall range of 0.22 to 1.81 mg/kg. Injury to beans occurred at soil concentrations equal to or greater than 1.0 mg/kg B. An added experiment (0,9,18 and 36 kgB/ha) in 1990 produced highly significant reductions in bean yields at B rates of 18 and 3 6 kg/ha. Yields did not vary significantly, however, between 0 and 9 kgB/ha. Boron concentrations in whole plant samples at the first trifoliate leaf stage ranged from 4 3 to 3 52 mg/kg. Soil B levels ranged from 0.3 5 to 4.07 mg/kg. Applied water levels of 77% and 69 to 87% of a calculated reference evapotranspiration coefficient (ETo) produced highest yields of bean pods in 1989 and 1990 respectively. Optimum yields for both seasons occurred when soil moisture levels (% moisture/ volume) were depleted to no less than 50% of available soil moisture. Total yields, inner quality and outer quality of cauliflower were not significantly affected by soil applied B rates as high as 9 kg/ha (as compared to 0, 1, 3 and 6 kgB/ha) during both the 1989 and 1990 seasons. Boron concentrations in leaf tissue at the highest (wet) water level ranged from 13.2 to 23.8 and 34.8 to 70.9 mg/kg in 1989 and 1990 respectively. Boron concentrations in leaf tissue were higher at the highest water level than at the lowest water level. Post harvest soil B concentrations ranged from 0.31 to 0.82 mg/kg at the highest water level in 1989 and 1990 respectively. In general, soil B concentrations were higher at the lowest (dry) water levels than at the highest water level. Highest yields were achieved at applied amounts of water that equaled 104 and 80% of ETo in 1989 and 1990 respectively. Corresponding soil moisture data (% moisture/volume) showed optimum yields occurring when available moisture remained above 50%. The frequency of good outer quality curds increased as water amounts increased. The frequency of good inner quality curds decreased as water amounts increased. Marketable yields at the lower moisture regimes, however, were marginal. Internal quality appeared to be a function of harvest date in this experiment. The frequency of head-hollowness and internal discoloration both decreased as the harvest season progressed. Percent good inner quality ranged from 48.5 to 84.7 and 34.9 to 91.1 between first and last harvests in 1989 and 1990 respectively. Boron migration or loss through the soil profile was greatest out of the top 0-15 cm depth and at the 9 kgB/ha rate. Losses as high as 39 and 49% in 1989/1990 and 1990/1991 seasons respectively, were found as a result of differential dates of soil sampling. In an additional experiment in the mid-summer of 1990 where rates of 9, 16 and 32 kgB/ha were applied, losses of B from the 0-15 cm depth ranged from 35 to 49%. Title: Effects of boron rates and differential irrigation on bush green beans and cauliflower Author: Grealish, William J. Five boron rates and seven water levels were applied to bush green beans (Phaseolus vulqaris cv Oregon 91G) and to cauliflower (Brassica olereacea var. botrytis, cultivar "Snowball Y") in 1989 and 1990 to evaluate their effects on total yield of both crops and on outer quality, head hollowness and internal discoloration of cauliflower curds. Of the five B rates (0,1,3,6 and 9kg/ha) three (0, 3 and 9 kg/ha) were monitored to evaluate B concentrations at soil depths of 0-15, 15-30, 30-45 and 45-60 cm. In each season, B concentrations were analyzed at a high (wet) level of applied water. An overall evaluation comparing the starting and ending levels of B after two years was conducted at two levels of applied water (high and low). Soil applied B rates of 9 kg/ha significantly reduced bean yields in 1989 and 1990. Boron concentrations in the trifoliate leaf tissue at the highest (wet) water level in 1989 and 1990 ranged between 22 to 72 mg/kg for the five B rates. Tissue concentrations at the lowest (dry) Water level in 1990 ranged from 23 to 32 mg/kg B. Soil B levels for both years had an overall range of 0.22 to 1.81 mg/kg. Injury to beans occurred at soil concentrations equal to or greater than 1.0 mg/kg B. An added experiment (0,9,18 and 36 kgB/ha) in 1990 produced highly significant reductions in bean yields at B rates of 18 and 3 6 kg/ha. Yields did not vary significantly, however, between 0 and 9 kgB/ha. Boron concentrations in whole plant samples at the first trifoliate leaf stage ranged from 4 3 to 3 52 mg/kg. Soil B levels ranged from 0.3 5 to 4.07 mg/kg. Applied water levels of 77% and 69 to 87% of a calculated reference evapotranspiration coefficient (ETo) produced highest yields of bean pods in 1989 and 1990 respectively. Optimum yields for both seasons occurred when soil moisture levels (% moisture/ volume) were depleted to no less than 50% of available soil moisture. Total yields, inner quality and outer quality of cauliflower were not significantly affected by soil applied B rates as high as 9 kg/ha (as compared to 0, 1, 3 and 6 kgB/ha) during both the 1989 and 1990 seasons. Boron concentrations in leaf tissue at the highest (wet) water level ranged from 13.2 to 23.8 and 34.8 to 70.9 mg/kg in 1989 and 1990 respectively. Boron concentrations in leaf tissue were higher at the highest water level than at the lowest water level. Post harvest soil B concentrations ranged from 0.31 to 0.82 mg/kg at the highest water level in 1989 and 1990 respectively. In general, soil B concentrations were higher at the lowest (dry) water levels than at the highest water level. Highest yields were achieved at applied amounts of water that equaled 104 and 80% of ETo in 1989 and 1990 respectively. Corresponding soil moisture data (% moisture/volume) showed optimum yields occurring when available moisture remained above 50%. The frequency of good outer quality curds increased as water amounts increased. The frequency of good inner quality curds decreased as water amounts increased. Marketable yields at the lower moisture regimes, however, were marginal. Internal quality appeared to be a function of harvest date in this experiment. The frequency of head-hollowness and internal discoloration both decreased as the harvest season progressed. Percent good inner quality ranged from 48.5 to 84.7 and 34.9 to 91.1 between first and last harvests in 1989 and 1990 respectively. Boron migration or loss through the soil profile was greatest out of the top 0-15 cm depth and at the 9 kgB/ha rate. Losses as high as 39 and 49% in 1989/1990 and 1990/1991 seasons respectively, were found as a result of differential dates of soil sampling. In an additional experiment in the mid-summer of 1990 where rates of 9, 16 and 32 kgB/ha were applied, losses of B from the 0-15 cm depth ranged from 35 to 49%. Close

• 1419. [Article] Biological attributes and alteration of the habitat to manipulate populations of Labops hesperius Uhler (Heteroptera:Miridae)

  Biological attributes and alteration of the habitat of Labops hesperius Uhler were investigated on rangeland seeded to crested wheatgrass near Vale, Oregon, and on rangeland seeded to crested and intermediate ...

  Citation × Citation Citation Abstract Copy Title: Biological attributes and alteration of the habitat to manipulate populations of Labops hesperius Uhler (Heteroptera:Miridae) Author: Fuxa, James R. Biological attributes and alteration of the habitat of Labops hesperius Uhler were investigated on rangeland seeded to crested wheatgrass near Vale, Oregon, and on rangeland seeded to crested and intermediate wheatgrass near Seneca, Oregon. Nymphs and adults were present at Vale from late March until mid-June and at Seneca from early April until late June or early July. Females at the Vale site preferred to oviposit in dry culms of crested wheatgrass and in Sandberg's bluegrass but they also oviposited in cheatgrass and green calms of crested wheatgrass. Females at a Seneca site oviposited in green intermediate wheatgrass. Population density at the Vale site was positively correlated with the total weight of dry wheatgrass and ground litter present at different locations because the straw provided oviposition sites or protection for the bugs. The obligatory egg diapause was investigated by subjecting eggs collected in September to different temperature treatments in the laboratory. Diapause was terminated after a minimum of 60 days exposure to 3° or 9° C and about two weeks incubation in 15°C and 16-hour photophase. Eggs survived temperatures as low as -15° C, and one temperature treatment resulted in 87% hatch. A 30 day acclimation temperature of 9° or 3° C before exposing the eggs to 3° or -15°C, respectively, resulted in a higher egg-hatch percentage. Egg diapause in L. hesperius differed from that in other mirids because the embryo of the former diapaused at a more advanced stage of embryogenesis. Sticky traps, pitfall traps, and a marking technique were used to study dispersal capabilities of L. hesperius at the Vale site. The bugs were capable of moving 7. 8 meters by walking on the ground and 23. 2 meters by a combination of flying and walking. The bugs could perceive red, yellow, and blue traps, but not white traps, at an altitude of 1. 52 meters, which was the common flight altitude. Macropterous females attained sexual maturity later than brachypterous females indicating that the former are specialized for migration. Males flew but the trap data did not indicate whether the nature of their flight was dispersal or trivial. The low percentage of macropterous females in the population might explain the slow dispersal rate of L. hesperius. Another mirid, Irbisia brachycera Uhler, was also captured in large numbers on sticky traps. Feeding damage to wheatgrass plants was studied by visual evaluation and chemical analysis of the damaged leaves. Chemical analysis indicated that feeding damage caused a decrease in plant cell contents but an increase in digestibility of the cell-wall constituents. However, a damage level of only 25% caused a relative increase in cell-wall constituents to an extent that would probably decrease the voluntary intake of wheatgrass by ruminants. Various range cultural and management practices were investigated to determine whether they could be used to reduce the population density of L. hesperius. Fertilizer treatments that included nitrogen significantly increased the density of L. hesperius but none of the fertilizer treatments significantly decreased the density. The bug density did not increase in proportion to the increase in herbage yield expected from fertilizing wheatgrass with nitrogen. The herbicide Paraquat indirectly killed nymphs and adults of L. hesperius by prematurely curing the wheatgrass which resulted in starvation of the bugs. The egg density was also reduced because the females starved to death before they were able to oviposit. Paraquat reduced the herbage yield as expected but increased the quality of the herbage. Prematurely curing wheatgrass with Paraquat will be an economical method of controlling L. hesperius provided that the spray can be timed to both reduce the bug population and increase the feed value of the forage. Mechanical removal of herbage during the egg stage reduced the bug population density by directly destroying the eggs or by exposing them to more harsh winter conditions or both. Mechanical removal during the nymphal and adult stages did not directly affect the population density since the bugs were able to find sufficient food for survival in the stubble. However, mechanical removal of herbage during the nymphal stages can reduce bug density in populations that are relatively dense originally, and removal immediately before oviposition prevents the females from laying eggs. Field burning, hay crop removal, and grazing are cultural practices that might control L. hesperius by mechanically removing the herbage. Hay crop removal, grazing during the nymphal and early adult stages, and grazing during the egg stage should each prove useful for controlling L. hesperius on different types of pasture infested with bugs. Title: Biological attributes and alteration of the habitat to manipulate populations of Labops hesperius Uhler (Heteroptera:Miridae) Author: Fuxa, James R. Biological attributes and alteration of the habitat of Labops hesperius Uhler were investigated on rangeland seeded to crested wheatgrass near Vale, Oregon, and on rangeland seeded to crested and intermediate wheatgrass near Seneca, Oregon. Nymphs and adults were present at Vale from late March until mid-June and at Seneca from early April until late June or early July. Females at the Vale site preferred to oviposit in dry culms of crested wheatgrass and in Sandberg's bluegrass but they also oviposited in cheatgrass and green calms of crested wheatgrass. Females at a Seneca site oviposited in green intermediate wheatgrass. Population density at the Vale site was positively correlated with the total weight of dry wheatgrass and ground litter present at different locations because the straw provided oviposition sites or protection for the bugs. The obligatory egg diapause was investigated by subjecting eggs collected in September to different temperature treatments in the laboratory. Diapause was terminated after a minimum of 60 days exposure to 3° or 9° C and about two weeks incubation in 15°C and 16-hour photophase. Eggs survived temperatures as low as -15° C, and one temperature treatment resulted in 87% hatch. A 30 day acclimation temperature of 9° or 3° C before exposing the eggs to 3° or -15°C, respectively, resulted in a higher egg-hatch percentage. Egg diapause in L. hesperius differed from that in other mirids because the embryo of the former diapaused at a more advanced stage of embryogenesis. Sticky traps, pitfall traps, and a marking technique were used to study dispersal capabilities of L. hesperius at the Vale site. The bugs were capable of moving 7. 8 meters by walking on the ground and 23. 2 meters by a combination of flying and walking. The bugs could perceive red, yellow, and blue traps, but not white traps, at an altitude of 1. 52 meters, which was the common flight altitude. Macropterous females attained sexual maturity later than brachypterous females indicating that the former are specialized for migration. Males flew but the trap data did not indicate whether the nature of their flight was dispersal or trivial. The low percentage of macropterous females in the population might explain the slow dispersal rate of L. hesperius. Another mirid, Irbisia brachycera Uhler, was also captured in large numbers on sticky traps. Feeding damage to wheatgrass plants was studied by visual evaluation and chemical analysis of the damaged leaves. Chemical analysis indicated that feeding damage caused a decrease in plant cell contents but an increase in digestibility of the cell-wall constituents. However, a damage level of only 25% caused a relative increase in cell-wall constituents to an extent that would probably decrease the voluntary intake of wheatgrass by ruminants. Various range cultural and management practices were investigated to determine whether they could be used to reduce the population density of L. hesperius. Fertilizer treatments that included nitrogen significantly increased the density of L. hesperius but none of the fertilizer treatments significantly decreased the density. The bug density did not increase in proportion to the increase in herbage yield expected from fertilizing wheatgrass with nitrogen. The herbicide Paraquat indirectly killed nymphs and adults of L. hesperius by prematurely curing the wheatgrass which resulted in starvation of the bugs. The egg density was also reduced because the females starved to death before they were able to oviposit. Paraquat reduced the herbage yield as expected but increased the quality of the herbage. Prematurely curing wheatgrass with Paraquat will be an economical method of controlling L. hesperius provided that the spray can be timed to both reduce the bug population and increase the feed value of the forage. Mechanical removal of herbage during the egg stage reduced the bug population density by directly destroying the eggs or by exposing them to more harsh winter conditions or both. Mechanical removal during the nymphal and adult stages did not directly affect the population density since the bugs were able to find sufficient food for survival in the stubble. However, mechanical removal of herbage during the nymphal stages can reduce bug density in populations that are relatively dense originally, and removal immediately before oviposition prevents the females from laying eggs. Field burning, hay crop removal, and grazing are cultural practices that might control L. hesperius by mechanically removing the herbage. Hay crop removal, grazing during the nymphal and early adult stages, and grazing during the egg stage should each prove useful for controlling L. hesperius on different types of pasture infested with bugs. Close

• 1420. [Article] The effect of games on cognitive abilities and on attitudes toward mathematics

  The purpose of this investigation was to determine if either of two selected commercial games, when used by seventh-grade mathematics teachers, would significantly improve students' (1) attitudes toward ...

  Citation × Citation Citation Abstract Copy Title: The effect of games on cognitive abilities and on attitudes toward mathematics Author: Henry, Kermit Maxson The purpose of this investigation was to determine if either of two selected commercial games, when used by seventh-grade mathematics teachers, would significantly improve students' (1) attitudes toward mathematics, (2) quantitative cognitive abilities, and (3) nonverbal cognitive abilities. Equations, a mathematics game, and Tac-Tickle, a strategy game, were chosen as representatives of commercial games available to classroom teachers. The instruments used to measure cognitive abilities and attitudes were the Quantitative and Nonverbal Batteries of the Cognitive Abilities Test (CAT), Level F and Dutton's Attitude Scale. The major research hypotheses were as follows: H₁: Student-participation in games will improve attitudes toward mathematics as measured by the Dutton Attitude Scale. H₂: Student-participation in games will increase quantitative cognitive abilities as measured by the Quantitative CAT. H₃: Student-participation in games will increase nonverbal cognitive abilities as measured by the Nonverbal CAT. In addition, subtests of the Quantitative and Nonverbal CAT Batteries were used to measure six minor hypotheses. A three-way analysis of covariance was employed to test the three major and six minor hypotheses. Pretest scores were used as the covariate. Seven F-values were calculated for each hypothesis to compare variations in adjusted posttest gains attributable to (1) sex, (2) school, (3) treatment, (4) sex-by-school, (5) sex-by-treatment, (6) school-by-treatment, and (7) sex-by-school-by-treatment. Subjects for the experiment were 182 students from nine seventh-grade mathematics classes in three junior high schools. One experienced mathematics teacher in each of the three schools assisted in the experiment. Each game was randomly assigned as a treatment variable to one of three classes taught by each teacher. Hence, each teacher instructed one control class, one Equations experimental class, and one Tac-Tickle experimental class. All nine classes were pretested with the Dutton Attitude Scale and the two batteries of the CAT. Students in the experimental classes played games for half the class period approximately every other day for six weeks. Conventional classroom lessons continued intermittently with game-instruction. At the conclusion of the experiment, all classes were posttested with the Dutton Attitude Scale and the two CAT batteries. Findings The 21 F-values for the three major hypotheses were not significant at the .05 level. Three F-values were found to be significant for the minor hypotheses. Differences in adjusted mean gain scores on the Equations Building subtest of the Quantitative CAT were significant for school and for school-by-treatment interaction. Also, school variability in adjusted mean gain scores on the Figure Synthesis subtest of the Nonverbal CAT was significant. As a further analysis not related to the hypotheses, pretest scores on the Dutton Attitude Scale and the two batteries of the CAT were used to identify the top 30 and bottom 30 percent of the students in the control group, in the Equations group, and in the Tac-Tickle group. F-Tests were used to compare variations in adjusted attitude and cognitive ability mean gain scores between the top three groups. The resulting F-values were not significant. The bottom 30 percent groups were also compared by the same procedure. Again, no significant differences were found. Finally, t-test score gain comparisons were made between the top 30 and bottom 30 percent within each of the three groups. The calculated t-values revealed no significant differences between top and bottom students on any of the three measures. The salient results of this investigation were as follows: 1. The intermittent use of games by actual classroom teachers was found to be as effective as conventional instruction in terms of increasing students' attitude and cognitive ability scores. 2. Game-participation did not produce significant boy-girl differences in attitude and cognitive ability scores. 3. Treatment comparisons between two types of commercial games revealed no significant differences in attitude and cognitive ability mean score gains. 4. The results of the study indicated that teacher variability was a significant factor in the learning of mathematics-equation comprehension and spatial relations through the use of games. Title: The effect of games on cognitive abilities and on attitudes toward mathematics Author: Henry, Kermit Maxson The purpose of this investigation was to determine if either of two selected commercial games, when used by seventh-grade mathematics teachers, would significantly improve students' (1) attitudes toward mathematics, (2) quantitative cognitive abilities, and (3) nonverbal cognitive abilities. Equations, a mathematics game, and Tac-Tickle, a strategy game, were chosen as representatives of commercial games available to classroom teachers. The instruments used to measure cognitive abilities and attitudes were the Quantitative and Nonverbal Batteries of the Cognitive Abilities Test (CAT), Level F and Dutton's Attitude Scale. The major research hypotheses were as follows: H₁: Student-participation in games will improve attitudes toward mathematics as measured by the Dutton Attitude Scale. H₂: Student-participation in games will increase quantitative cognitive abilities as measured by the Quantitative CAT. H₃: Student-participation in games will increase nonverbal cognitive abilities as measured by the Nonverbal CAT. In addition, subtests of the Quantitative and Nonverbal CAT Batteries were used to measure six minor hypotheses. A three-way analysis of covariance was employed to test the three major and six minor hypotheses. Pretest scores were used as the covariate. Seven F-values were calculated for each hypothesis to compare variations in adjusted posttest gains attributable to (1) sex, (2) school, (3) treatment, (4) sex-by-school, (5) sex-by-treatment, (6) school-by-treatment, and (7) sex-by-school-by-treatment. Subjects for the experiment were 182 students from nine seventh-grade mathematics classes in three junior high schools. One experienced mathematics teacher in each of the three schools assisted in the experiment. Each game was randomly assigned as a treatment variable to one of three classes taught by each teacher. Hence, each teacher instructed one control class, one Equations experimental class, and one Tac-Tickle experimental class. All nine classes were pretested with the Dutton Attitude Scale and the two batteries of the CAT. Students in the experimental classes played games for half the class period approximately every other day for six weeks. Conventional classroom lessons continued intermittently with game-instruction. At the conclusion of the experiment, all classes were posttested with the Dutton Attitude Scale and the two CAT batteries. Findings The 21 F-values for the three major hypotheses were not significant at the .05 level. Three F-values were found to be significant for the minor hypotheses. Differences in adjusted mean gain scores on the Equations Building subtest of the Quantitative CAT were significant for school and for school-by-treatment interaction. Also, school variability in adjusted mean gain scores on the Figure Synthesis subtest of the Nonverbal CAT was significant. As a further analysis not related to the hypotheses, pretest scores on the Dutton Attitude Scale and the two batteries of the CAT were used to identify the top 30 and bottom 30 percent of the students in the control group, in the Equations group, and in the Tac-Tickle group. F-Tests were used to compare variations in adjusted attitude and cognitive ability mean gain scores between the top three groups. The resulting F-values were not significant. The bottom 30 percent groups were also compared by the same procedure. Again, no significant differences were found. Finally, t-test score gain comparisons were made between the top 30 and bottom 30 percent within each of the three groups. The calculated t-values revealed no significant differences between top and bottom students on any of the three measures. The salient results of this investigation were as follows: 1. The intermittent use of games by actual classroom teachers was found to be as effective as conventional instruction in terms of increasing students' attitude and cognitive ability scores. 2. Game-participation did not produce significant boy-girl differences in attitude and cognitive ability scores. 3. Treatment comparisons between two types of commercial games revealed no significant differences in attitude and cognitive ability mean score gains. 4. The results of the study indicated that teacher variability was a significant factor in the learning of mathematics-equation comprehension and spatial relations through the use of games. Close