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• 13091. [Article] Analysis of selected factors relating to academic success, utilization of training and return home of Latin American students who have graduated from the California State College system

  Purpose of the Study The purposes of this study were to (1) identify the educational and socioeconomic characteristics of Latin American students who have graduated from the California State College system, ...

  Citation × Citation Citation Abstract Copy Title: Analysis of selected factors relating to academic success, utilization of training and return home of Latin American students who have graduated from the California State College system Author: Fretwell, David Herbert Purpose of the Study The purposes of this study were to (1) identify the educational and socioeconomic characteristics of Latin American students who have graduated from the California State College system, (2) to identify those characteristics which significantly affect academic success, utilization of training and return home to Latin America after graduation and (3) to develop mathematical models for prediction of academic success, utilization of training and return home. Procedures A total of 146 students were included in the sample for this study. These students had graduated from the California State College system in the five years prior to August 30, 1971. Socio-economic and educational characteristics were obtained through a search of college records, interviews with faculty and staff and the mailing of a questionnaire to the students included in the sample. Academic success was defined by grade point average and utilization of training was measured in percentage by the amount of college training used by a graduate in his present job. A correlation analysis was completed to determine the relationship among the three dependent variables academic success, utilization of training and return home as well as the relationship between each of the dependent variables and the independent variables included in the study, Stepwise multiple linear regression analyses identified those characteristics contributing most significantly to academic success and utilization of training. These analyses were also used to develop prediction equations for academic success and utilization of training. Discriminant analyses were completed to test the null hypothesis that there was no significant difference between the returning and non-returning group of students and to construct a prediction model for return or non-return to native country. Findings 1. The correlation analysis indicated the following: (a) There was no significant relationship among the three dependent variables: academic success, utilization of training and return home. (b) Six independent variables had a significant relationship with academic success. One, bachelor's degree, was negatively correlated while the remainder, graduate degree training, average English grade, prior college in native country, education major and scholarship financing,were positively correlated. (c) No independent variables were identified that had a significant relationship with the dependent variable utilization of training. (d) Two independent variables, contact with Latin America while training and vacations spent in Latin America were positively correlated with the dependent variable return home. It was emphasized that these were simple linear relationships that did not indicate' causality. 2. The results of the linear regression analysis related to academic success indicated: (a) Nine variables were significantly related to academic success. Four of these variables had a positive relationship: average English grade, education major, "other" major (including majors other than agriculture, business, engineering and education) and vacations spent in Latin America. Five of these variables had a negative relationship: return home, California State Polytechnic College - San Luis Obispo, California State College - Long Beach, time in the U. S. before graduation, and F visa. (b) A prediction equation was constructed for academic success, The equation constructed included the variables: San Francisco State College, California State College - Long Beach, California, State Polytechnic College - San Luis Obispo, age, education, major and "other" major. 3. The results of the linear regression analysis related to utilization of training indicated: (a) Twelve variables were significantly related to utilization of training. Six of these had a positive relationship: bachelor's degree, engineering major, father's occupation similar to student's field of study, contact with Latin America while training, Latin America high school training and present employment at a higher level. Six of these variables had a negative relationship: age, marriage during training, family financing and follow-up contact after graduation. (b) A prediction equation was constructed for utilization of training. The equation constructed included the variables: Fresno State College, prior employment in field of training, father's occupation similar and orientation program available. 4. The null hypothesis, stating that there was no significant difference between the returning and non-returning groups of students, could not be rejected on the basis of the discriminant analyses completed. Therefore a prediction model for return could not be constructed. Title: Analysis of selected factors relating to academic success, utilization of training and return home of Latin American students who have graduated from the California State College system Author: Fretwell, David Herbert Purpose of the Study The purposes of this study were to (1) identify the educational and socioeconomic characteristics of Latin American students who have graduated from the California State College system, (2) to identify those characteristics which significantly affect academic success, utilization of training and return home to Latin America after graduation and (3) to develop mathematical models for prediction of academic success, utilization of training and return home. Procedures A total of 146 students were included in the sample for this study. These students had graduated from the California State College system in the five years prior to August 30, 1971. Socio-economic and educational characteristics were obtained through a search of college records, interviews with faculty and staff and the mailing of a questionnaire to the students included in the sample. Academic success was defined by grade point average and utilization of training was measured in percentage by the amount of college training used by a graduate in his present job. A correlation analysis was completed to determine the relationship among the three dependent variables academic success, utilization of training and return home as well as the relationship between each of the dependent variables and the independent variables included in the study, Stepwise multiple linear regression analyses identified those characteristics contributing most significantly to academic success and utilization of training. These analyses were also used to develop prediction equations for academic success and utilization of training. Discriminant analyses were completed to test the null hypothesis that there was no significant difference between the returning and non-returning group of students and to construct a prediction model for return or non-return to native country. Findings 1. The correlation analysis indicated the following: (a) There was no significant relationship among the three dependent variables: academic success, utilization of training and return home. (b) Six independent variables had a significant relationship with academic success. One, bachelor's degree, was negatively correlated while the remainder, graduate degree training, average English grade, prior college in native country, education major and scholarship financing,were positively correlated. (c) No independent variables were identified that had a significant relationship with the dependent variable utilization of training. (d) Two independent variables, contact with Latin America while training and vacations spent in Latin America were positively correlated with the dependent variable return home. It was emphasized that these were simple linear relationships that did not indicate' causality. 2. The results of the linear regression analysis related to academic success indicated: (a) Nine variables were significantly related to academic success. Four of these variables had a positive relationship: average English grade, education major, "other" major (including majors other than agriculture, business, engineering and education) and vacations spent in Latin America. Five of these variables had a negative relationship: return home, California State Polytechnic College - San Luis Obispo, California State College - Long Beach, time in the U. S. before graduation, and F visa. (b) A prediction equation was constructed for academic success, The equation constructed included the variables: San Francisco State College, California State College - Long Beach, California, State Polytechnic College - San Luis Obispo, age, education, major and "other" major. 3. The results of the linear regression analysis related to utilization of training indicated: (a) Twelve variables were significantly related to utilization of training. Six of these had a positive relationship: bachelor's degree, engineering major, father's occupation similar to student's field of study, contact with Latin America while training, Latin America high school training and present employment at a higher level. Six of these variables had a negative relationship: age, marriage during training, family financing and follow-up contact after graduation. (b) A prediction equation was constructed for utilization of training. The equation constructed included the variables: Fresno State College, prior employment in field of training, father's occupation similar and orientation program available. 4. The null hypothesis, stating that there was no significant difference between the returning and non-returning groups of students, could not be rejected on the basis of the discriminant analyses completed. Therefore a prediction model for return could not be constructed. Close

• 13092. [Article] Improving Projections of Tidal Marsh Persistence under Climate Change with Remote Sensing and Site-Specific Data

  Tidal marshes are dynamic ecosystems that are threatened by climate change and sea-level rise. To characterize baseline condition and historic climate sensitivities, and improve projections into the future, ...

  Citation × Citation Citation Abstract Copy Title: Improving Projections of Tidal Marsh Persistence under Climate Change with Remote Sensing and Site-Specific Data Author: Buffington, Kevin John Tidal marshes are dynamic ecosystems that are threatened by climate change and sea-level rise. To characterize baseline condition and historic climate sensitivities, and improve projections into the future, new methods are required that integrate data from the field and remote sensing platforms. Marsh elevation response models can be calibrated with site-specific data to determine the vulnerability of a marsh to sea-level rise and help guide management decisions. Elevation models are sensitive to initial elevation, the rate of accretion, and aboveground biomass. The overarching goal of this dissertation was to develop techniques to improve these important model inputs and evaluate the range of spatial and temporal variation. Light detection and ranging (lidar) is an invaluable tool for collecting elevation data, however dense vegetation prevents the accurate measurement of the tidal marsh surface. In Chapter 2, I describe the development of a technique to calibrate lidar digital elevation models with survey elevation data using readily available multispectral aerial imagery from the National Agricultural Inventory Program (NAIP). Using survey elevation data across 17 Pacific Coast tidal marshes, I demonstrated the utility of the Lidar Elevation Adjustment with NDVI (LEAN) technique to account for the positive bias in lidar due to vegetation. LEAN reduced error from an average of 23.1 cm to 7.2 cm root mean squared error and removed the positive bias caused by vegetation. This increase in accuracy will facilitate more accurate assessments of current and future vulnerability to sea-level rise. The phenology of aboveground biomass in tidal marsh plants in relation to climate variation has not been explored in the Pacific Northwest (PNW). In Chapter 3 I explain how I leveraged the Landsat archive and cloud computing capabilities to assess how Tasseled Cap Greenness (TCG, a proxy for aboveground biomass) in three PNW tidal marshes has responded to recent variation in climate to characterize sensitivity to climate change. Through analysis of over 3700 Landsat images obtained from 1984-2015, I found increased annual precipitation resulted in a higher peak TCG, while warmer May temperatures resulted in an earlier day of peak TCG. These results also demonstrate how time-series analysis of remote sensing data can be used to examine the sensitivity of tidal marsh plants to climate variability and directional change. The range of variation in tidal marsh accretion rates has not been characterized across the PNW. For Chapter 4, I collected and analyzed twenty-two soil cores from eight estuaries to estimate historic accretion rates with radioisotope dating techniques and evaluated the amount and source of variation across estuaries. I found that tidal marshes across the PNW had accretion rates greater than the current rate of sea-level rise, ranging from 2.3 – 7.3 mm yr⁻¹. Using a watershed-scale analysis, I found that long-term average annual fluvial discharge was the top predictor of tidal marsh accretion rates. Additionally, I found that calibrating the Wetland Accretion Rate Model for Ecosystem Resilience (WARMER) with accretion rate data from nearby estuaries can result in uncertainties of up to 41% (50 cm) after 100 years. Finally, in Chapter 5, I demonstrate that a range of 62 cm of error is possible in WARMER models after a 100 year simulation when both uncorrected lidar and non-local accretion rates are used, fundamentally changing the interpretation of the results. Altogether, this dissertation illustrates the importance of collecting site-specific wetland vegetation and elevation data and demonstrates how lidar and multispectral remote sensing data can be leveraged to improve our understanding of how climate variability and change impacts coastal ecosystems. Title: Improving Projections of Tidal Marsh Persistence under Climate Change with Remote Sensing and Site-Specific Data Author: Buffington, Kevin John Tidal marshes are dynamic ecosystems that are threatened by climate change and sea-level rise. To characterize baseline condition and historic climate sensitivities, and improve projections into the future, new methods are required that integrate data from the field and remote sensing platforms. Marsh elevation response models can be calibrated with site-specific data to determine the vulnerability of a marsh to sea-level rise and help guide management decisions. Elevation models are sensitive to initial elevation, the rate of accretion, and aboveground biomass. The overarching goal of this dissertation was to develop techniques to improve these important model inputs and evaluate the range of spatial and temporal variation. Light detection and ranging (lidar) is an invaluable tool for collecting elevation data, however dense vegetation prevents the accurate measurement of the tidal marsh surface. In Chapter 2, I describe the development of a technique to calibrate lidar digital elevation models with survey elevation data using readily available multispectral aerial imagery from the National Agricultural Inventory Program (NAIP). Using survey elevation data across 17 Pacific Coast tidal marshes, I demonstrated the utility of the Lidar Elevation Adjustment with NDVI (LEAN) technique to account for the positive bias in lidar due to vegetation. LEAN reduced error from an average of 23.1 cm to 7.2 cm root mean squared error and removed the positive bias caused by vegetation. This increase in accuracy will facilitate more accurate assessments of current and future vulnerability to sea-level rise. The phenology of aboveground biomass in tidal marsh plants in relation to climate variation has not been explored in the Pacific Northwest (PNW). In Chapter 3 I explain how I leveraged the Landsat archive and cloud computing capabilities to assess how Tasseled Cap Greenness (TCG, a proxy for aboveground biomass) in three PNW tidal marshes has responded to recent variation in climate to characterize sensitivity to climate change. Through analysis of over 3700 Landsat images obtained from 1984-2015, I found increased annual precipitation resulted in a higher peak TCG, while warmer May temperatures resulted in an earlier day of peak TCG. These results also demonstrate how time-series analysis of remote sensing data can be used to examine the sensitivity of tidal marsh plants to climate variability and directional change. The range of variation in tidal marsh accretion rates has not been characterized across the PNW. For Chapter 4, I collected and analyzed twenty-two soil cores from eight estuaries to estimate historic accretion rates with radioisotope dating techniques and evaluated the amount and source of variation across estuaries. I found that tidal marshes across the PNW had accretion rates greater than the current rate of sea-level rise, ranging from 2.3 – 7.3 mm yr⁻¹. Using a watershed-scale analysis, I found that long-term average annual fluvial discharge was the top predictor of tidal marsh accretion rates. Additionally, I found that calibrating the Wetland Accretion Rate Model for Ecosystem Resilience (WARMER) with accretion rate data from nearby estuaries can result in uncertainties of up to 41% (50 cm) after 100 years. Finally, in Chapter 5, I demonstrate that a range of 62 cm of error is possible in WARMER models after a 100 year simulation when both uncorrected lidar and non-local accretion rates are used, fundamentally changing the interpretation of the results. Altogether, this dissertation illustrates the importance of collecting site-specific wetland vegetation and elevation data and demonstrates how lidar and multispectral remote sensing data can be leveraged to improve our understanding of how climate variability and change impacts coastal ecosystems. Close

• 13093. [Article] The economic impact of the 1964 Fair Employment Practices Act and subsequent executive orders on Black Americans

  The economic status of the Black Americans has lagged far behind that of non-Black Americans in the last four centuries. The major reasons are manifested in (1) discrimination in employment practices by: ...

  Citation × Citation Citation Abstract Copy Title: The economic impact of the 1964 Fair Employment Practices Act and subsequent executive orders on Black Americans Author: Mbatia, Oliver Lee E. The economic status of the Black Americans has lagged far behind that of non-Black Americans in the last four centuries. The major reasons are manifested in (1) discrimination in employment practices by: employers, public and private employment agencies, labor organizations, and apprenticeship agencies; and (2) discrimination in distribution of factor inputs. To bring about economic equality the Presidents of the United States have issued various Executive Orders. Eight years ago the United States Congress enacted the Civil Rights Act of 1964 (Title VII of this Act is known as the Equal Employment Opportunity Title) and made it unlawful to discriminate in employment because of race, color, religion, sex, or national origin. The objective of this study is to examine the effects of the Civil Rights Act of 1964 and other Presidential Executive Orders on the related economic status of Black Americans. To examine this question, an economic model was developed. In this model, employers are assumed to have a "taste for discrimination," which causes them to have two different market demand curves for Blacks and non-Blacks. In hiring Black workers, employers feel that they incur a cost in addition to the market wage. Therefore Black workers are paid lower wages than non-Black workers in order for employers to compensate their "psychic cost." In this imperfect market Black workers are not perfect substitutes for non-Black workers. The enactment of the Fair Employment Practices laws (FEP) was, presumably, designed to encourage employers to regard Black workers as perfect substitutes for non-Black workers. Through causing employers "taste for discrimination" to disappear, it is expected that the demand curve for Black workers will shift to the right. The increase in demand would effect an increase in employment and wages for the Black Americans. On the other hand, negative effects could cause an increase in the wage rate and an increase in the unemployment rate. It is argued that the non-Black wage would remain the same, but, in the absence of eliminating the "taste for discrimination" the laws could result in an increase in the unemployment rate of the non-Blacks. The quantitative analysis was made by use of the census data in examining variables selected to measure economic status: viz., income, unemployment rates, and occupation distribution. In order to isolate the effects of the FEP laws on these variables, other variables were included, such as growth rate of Gross National Product and a dummy variable to test the impact of the war. Three statistical techniques were employed to evaluate the general overall economic progress of Blacks and the impact of the FEP laws. The statistical techniques are: least square regression analysis, analysis of variance, and information theory analysis technique. The regression results of many coefficients were not statistically significant at the five percent level of significance. In one instance the FEP laws effect variable was significant at the ten percent level of significance, suggesting that there may exist a relationship between that variable and unemployment rates. The statistical tests do not persuade one to conclude that the FEP laws have had significant impacts on the improvement of the economic status of the Black Americans. However, finding an expected sign on the estimated coefficients the FEP law effect variable suggests that the FEP laws, if more fully implemented, might lead to a reduction in unemployment and an increase in wage rate for Black Americans as a result of a shift in the demand curve for Black labor. The analysis of variance, revealed race itself to be dominantly significant as the cause of economic inequality of the two races. The racial entropy index distribution shows that the Blacks have made some progress in some occupations and have moved to better paying jobs. The descriptive analysis of the charges filed over the four year fiscal period, indicate that over 50 percent of the charges were directed to employers; and that the factor of race was very frequently given as the basis of the discrimination. Title: The economic impact of the 1964 Fair Employment Practices Act and subsequent executive orders on Black Americans Author: Mbatia, Oliver Lee E. The economic status of the Black Americans has lagged far behind that of non-Black Americans in the last four centuries. The major reasons are manifested in (1) discrimination in employment practices by: employers, public and private employment agencies, labor organizations, and apprenticeship agencies; and (2) discrimination in distribution of factor inputs. To bring about economic equality the Presidents of the United States have issued various Executive Orders. Eight years ago the United States Congress enacted the Civil Rights Act of 1964 (Title VII of this Act is known as the Equal Employment Opportunity Title) and made it unlawful to discriminate in employment because of race, color, religion, sex, or national origin. The objective of this study is to examine the effects of the Civil Rights Act of 1964 and other Presidential Executive Orders on the related economic status of Black Americans. To examine this question, an economic model was developed. In this model, employers are assumed to have a "taste for discrimination," which causes them to have two different market demand curves for Blacks and non-Blacks. In hiring Black workers, employers feel that they incur a cost in addition to the market wage. Therefore Black workers are paid lower wages than non-Black workers in order for employers to compensate their "psychic cost." In this imperfect market Black workers are not perfect substitutes for non-Black workers. The enactment of the Fair Employment Practices laws (FEP) was, presumably, designed to encourage employers to regard Black workers as perfect substitutes for non-Black workers. Through causing employers "taste for discrimination" to disappear, it is expected that the demand curve for Black workers will shift to the right. The increase in demand would effect an increase in employment and wages for the Black Americans. On the other hand, negative effects could cause an increase in the wage rate and an increase in the unemployment rate. It is argued that the non-Black wage would remain the same, but, in the absence of eliminating the "taste for discrimination" the laws could result in an increase in the unemployment rate of the non-Blacks. The quantitative analysis was made by use of the census data in examining variables selected to measure economic status: viz., income, unemployment rates, and occupation distribution. In order to isolate the effects of the FEP laws on these variables, other variables were included, such as growth rate of Gross National Product and a dummy variable to test the impact of the war. Three statistical techniques were employed to evaluate the general overall economic progress of Blacks and the impact of the FEP laws. The statistical techniques are: least square regression analysis, analysis of variance, and information theory analysis technique. The regression results of many coefficients were not statistically significant at the five percent level of significance. In one instance the FEP laws effect variable was significant at the ten percent level of significance, suggesting that there may exist a relationship between that variable and unemployment rates. The statistical tests do not persuade one to conclude that the FEP laws have had significant impacts on the improvement of the economic status of the Black Americans. However, finding an expected sign on the estimated coefficients the FEP law effect variable suggests that the FEP laws, if more fully implemented, might lead to a reduction in unemployment and an increase in wage rate for Black Americans as a result of a shift in the demand curve for Black labor. The analysis of variance, revealed race itself to be dominantly significant as the cause of economic inequality of the two races. The racial entropy index distribution shows that the Blacks have made some progress in some occupations and have moved to better paying jobs. The descriptive analysis of the charges filed over the four year fiscal period, indicate that over 50 percent of the charges were directed to employers; and that the factor of race was very frequently given as the basis of the discrimination. Close

• 13094. [Article] Evaluation of bamboo as livestock forage and applications of Yucca schidigera and Quillaja saponaria products in agriculture

  Byproducts of bamboo processing, such as leaves and branches, may have potential as a livestock feedstuff. The objectives of this study were to evaluate seasonal changes in proximate composition of several ...

  Citation × Citation Citation Abstract Copy Title: Evaluation of bamboo as livestock forage and applications of Yucca schidigera and Quillaja saponaria products in agriculture Author: Greenway, Stephanie L. Byproducts of bamboo processing, such as leaves and branches, may have potential as a livestock feedstuff. The objectives of this study were to evaluate seasonal changes in proximate composition of several bamboo species and reed canarygrass, and subsequently determine the digestibility of bamboo in ponies. Monthly samples of Phyllostachys bissetii, Phyllostachys henon, Sasa pumila, and reed canarygrass were evaluated for dry matter (DM), ash, crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), and acid detergent fiber (ADF) content over one year. Dry matter, ash, and CP for the bamboos and reed canarygrass were significantly influenced by an interaction between time of sampling and forage type (P<.0001; Extra-SS F-test). There were no interaction, quadratic, or linear effects of time on EE (P>.10; Extra-SS F-test). Neutral detergent fiber and ADF for all forages also were not affected by interactions or quadratic terms; however, a linear explanation of trends was significant. Two adult pony mares were used in a crossover design experiment to evaluate DM, CP, ADF, and NDF digestibility (DMD, CPD, ADFD, and NDFD, respectively) of the temperate bamboo, P. bissetii. The diets consisted of either l-inch chopped bamboo or grass hay. Feces were collected over 5-d periods after adaptation to diets. Dry matter digestibility, CPD, ADFD, and NDFD of the forages were generally below 30% in both ponies, with the CPD of bamboo being the only exception (75.4% for Pony A and 59.6% for Pony B). Acid detergent ash and acid detergent lignin values obtained for bamboo fed during both fecal collection periods were 2.9% and 3.6%, and 10.0% and 11.1%, respectively. The digestibility results indicate that bamboo foliage is similar in feed value to low-quality grass hay, with a DMD of approximately 30%. Feces from the two pony mares used in the previous in vivo experiment were collected to provide a source of inoculum for the in vitro dry matter disappearance {IVDMD) determination of four forages. Feedstuffs analyzed included bamboo fed during the two fecal collection periods of the previous in vivo experiment, as well as orchard grass hay and alfalfa hay. The effect of different levels (0, 250, 500, 750, 1500, and 3000 ppm) of Yucca schidigera extract (YE) on IVDMD of the bamboos and hays was determined. Addition of either 250 or 500 ppm YE did not affect bamboo IVDMD, whereas 3000 ppm decreased the digestibility of Bamboo Band increased that of orchard grass hay. Variable responses were seen when Bamboo B was treated with 750 ppm YE. No effect on alfalfa hay IVDMD was seen at any treatment level. The effects of YE treatment on feedstuffs in vitro are variable depending upon treatment level and type of forage evaluated. Yucca schidigera and Quillaja saponaria products were evaluated for their capacity to reduce ammonia emissions from poultry excreta. Yucca extract (YE), quillaja extract (QE), yucca ultra (YU), quillaja ultra (QU), yucca powder (DK-30), and quillaja powder (QCP) were evaluated at 0, 20, and 200 μL (mg for powders) per 5 g of excreta (wet wt.). Saponin, non-saponin, tannin, and non-tannin fractions of YE and QE (200 μL/5 g excreta) were also evaluated for ammonia reduction. Treatment with 200 μL QE/5 g excreta significantly reduced ammonia emissions when compared to all other products at either treatment level (P<.0001). All other treatments within the same level, but between different products were not significantly different from each other or the control (P>.05), except for DK-30. The higher treatment level (200 μL/5 g excreta) for all products combined was more effective (P<.0001) in reducing ammonia than 20 μL, which is to be expected. Treatment with the extracted fractions at 200 μL/5 g excreta were significantly different (P<.05) from each other when product type was not taken into account, except when comparing the percent ammonia reduction from carbohydrate treatment to that of the tannin fraction. Comparison of product means with all tannin, saponin, non-tannin, and non-saponin treatments combined were significantly different (P<.05). Pairwise comparisons of treatment fraction and product could not be obtained in the Mixed Linear Model. Of all standard products, QE reduced ammonia the most. The tannin-free component from both YE and QE appeared to be particularly effective in reducing emissions, with that of QE having the greater percent reduction. The reduced ammonia emissions observed when the non-saponin, and particularly the non-tannin fraction of YE and QE were applied to poultry excreta indicate the need for further investigation into determining the active compound in the non-saponin liquid. Title: Evaluation of bamboo as livestock forage and applications of Yucca schidigera and Quillaja saponaria products in agriculture Author: Greenway, Stephanie L. Byproducts of bamboo processing, such as leaves and branches, may have potential as a livestock feedstuff. The objectives of this study were to evaluate seasonal changes in proximate composition of several bamboo species and reed canarygrass, and subsequently determine the digestibility of bamboo in ponies. Monthly samples of Phyllostachys bissetii, Phyllostachys henon, Sasa pumila, and reed canarygrass were evaluated for dry matter (DM), ash, crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), and acid detergent fiber (ADF) content over one year. Dry matter, ash, and CP for the bamboos and reed canarygrass were significantly influenced by an interaction between time of sampling and forage type (P<.0001; Extra-SS F-test). There were no interaction, quadratic, or linear effects of time on EE (P>.10; Extra-SS F-test). Neutral detergent fiber and ADF for all forages also were not affected by interactions or quadratic terms; however, a linear explanation of trends was significant. Two adult pony mares were used in a crossover design experiment to evaluate DM, CP, ADF, and NDF digestibility (DMD, CPD, ADFD, and NDFD, respectively) of the temperate bamboo, P. bissetii. The diets consisted of either l-inch chopped bamboo or grass hay. Feces were collected over 5-d periods after adaptation to diets. Dry matter digestibility, CPD, ADFD, and NDFD of the forages were generally below 30% in both ponies, with the CPD of bamboo being the only exception (75.4% for Pony A and 59.6% for Pony B). Acid detergent ash and acid detergent lignin values obtained for bamboo fed during both fecal collection periods were 2.9% and 3.6%, and 10.0% and 11.1%, respectively. The digestibility results indicate that bamboo foliage is similar in feed value to low-quality grass hay, with a DMD of approximately 30%. Feces from the two pony mares used in the previous in vivo experiment were collected to provide a source of inoculum for the in vitro dry matter disappearance {IVDMD) determination of four forages. Feedstuffs analyzed included bamboo fed during the two fecal collection periods of the previous in vivo experiment, as well as orchard grass hay and alfalfa hay. The effect of different levels (0, 250, 500, 750, 1500, and 3000 ppm) of Yucca schidigera extract (YE) on IVDMD of the bamboos and hays was determined. Addition of either 250 or 500 ppm YE did not affect bamboo IVDMD, whereas 3000 ppm decreased the digestibility of Bamboo Band increased that of orchard grass hay. Variable responses were seen when Bamboo B was treated with 750 ppm YE. No effect on alfalfa hay IVDMD was seen at any treatment level. The effects of YE treatment on feedstuffs in vitro are variable depending upon treatment level and type of forage evaluated. Yucca schidigera and Quillaja saponaria products were evaluated for their capacity to reduce ammonia emissions from poultry excreta. Yucca extract (YE), quillaja extract (QE), yucca ultra (YU), quillaja ultra (QU), yucca powder (DK-30), and quillaja powder (QCP) were evaluated at 0, 20, and 200 μL (mg for powders) per 5 g of excreta (wet wt.). Saponin, non-saponin, tannin, and non-tannin fractions of YE and QE (200 μL/5 g excreta) were also evaluated for ammonia reduction. Treatment with 200 μL QE/5 g excreta significantly reduced ammonia emissions when compared to all other products at either treatment level (P<.0001). All other treatments within the same level, but between different products were not significantly different from each other or the control (P>.05), except for DK-30. The higher treatment level (200 μL/5 g excreta) for all products combined was more effective (P<.0001) in reducing ammonia than 20 μL, which is to be expected. Treatment with the extracted fractions at 200 μL/5 g excreta were significantly different (P<.05) from each other when product type was not taken into account, except when comparing the percent ammonia reduction from carbohydrate treatment to that of the tannin fraction. Comparison of product means with all tannin, saponin, non-tannin, and non-saponin treatments combined were significantly different (P<.05). Pairwise comparisons of treatment fraction and product could not be obtained in the Mixed Linear Model. Of all standard products, QE reduced ammonia the most. The tannin-free component from both YE and QE appeared to be particularly effective in reducing emissions, with that of QE having the greater percent reduction. The reduced ammonia emissions observed when the non-saponin, and particularly the non-tannin fraction of YE and QE were applied to poultry excreta indicate the need for further investigation into determining the active compound in the non-saponin liquid. Close

• 13095. [Article] Efficacy of water, sodium hypochlorite, peroxyacetic acid, and acidified sodium chlorite for reducing microorganisms on in-shell hazelnuts

  Hazelnuts are commonly consumed raw and are valued for their numerous health benefits and antioxidant properties. Increased foodborne illness outbreaks associated with Salmonella and Escherichia coli O157:H7 ...

  Citation × Citation Citation Abstract Copy Title: Efficacy of water, sodium hypochlorite, peroxyacetic acid, and acidified sodium chlorite for reducing microorganisms on in-shell hazelnuts Author: Weller, Lisa D. Hazelnuts are commonly consumed raw and are valued for their numerous health benefits and antioxidant properties. Increased foodborne illness outbreaks associated with Salmonella and Escherichia coli O157:H7 contamination of tree nuts and peanuts generate a need for improving agricultural sanitation procedures. Food-safe chemical sanitizers have shown promise for reducing pathogenic organisms on fresh produce, but minimal research has been conducted for in-shell nuts. The purpose of this study was to determine the effects of water and three food-safe sanitizers on a) the natural microbial load of postharvest in-shell hazelnuts and b) populations of pathogenic Salmonella (S. enterica subsp. enterica ser. Panama) inoculated and dried onto the surfaces of in-shell hazelnuts. The first phase of the study investigated the effectiveness of water, sodium hypochlorite (NaOCl; 25 ppm, 50 ppm), peroxyacetic acid (PAA; 80 ppm, 120 ppm), and acidified sodium chlorite (ASC; 990 ppm) as sanitizers for use on postharvest in-shell hazelnuts. Treatments were applied to two groups of freshly harvested hazelnut samples to examine their effects on total aerobic microorganism populations during different times of harvest (Group 1 = early season, dry weather; Group 2 = late season, rainy weather). Treatments within each group included hazelnuts that underwent a tap water rinse, a tap water rinse followed by a water spray, and a tap water rinse followed by a chemical spray. Due to excess soil attached to shell surface, hazelnuts harvested later in the season (Group 2) had an initial population mean 2.24 log CFU/hazelnut greater than hazelnuts harvested earlier in the season (Group 1). All treatments, including water, resulted in significant population reductions compared to untreated controls (P≤0.05). Rinsing with tap water produced reductions of 0.38 log units in both groups, and additional water spraying resulted in reductions of 0.83 and 0.73 log units in Group 1 and Group 2, respectively. None of the chemical treatments were significantly more effective than the water spray treatment in Group 1; however, several chemical treatments in Group 2 were significantly more effective than water spraying. Tight adherence to shell surfaces during dry weather may have increased the chemical resistance of microorganisms on hazelnuts. Treatment with ASC produced the greatest reduction in Group 1 and Group 2 compared to the control (1.22 and 2.08 log units, respectively) and water spray treatments (0.39 and 1.39 log units, respectively), but the efficacies varied between treatment groups. Wide variation between Group 1 and Group 2 treatment results made determination of chemical efficacy difficult. The second phase of the study analyzed the effectiveness of water, sodium hypochlorite (NaOCl; 25 ppm, 50 ppm), peroxyacetic acid (PAA; 80 ppm, 120 ppm), and acidified sodium chlorite (ASC; 450 ppm, 830 ppm, 1013 ppm) as sanitizers for reducing Salmonella on in-shell hazelnuts. Hazelnut samples were soaked in pure cultures of S. Panama for 24 h, air dried for 66 h, and then sprayed with water and chemical treatments. Surviving S. Panama populations were evaluated using a non-selective medium (tryptic soy agar), followed by a selective overlay (xylose lysine deoxycholate agar) after a 3 h incubation period. Tight adhesion prevented significant population decreases from physical removal by water, which allowed for clear demonstration of chemical effectiveness. All of the chemical treatments significantly reduced the S. Panama population (P≤0.05) compare to untreated and water-sprayed samples. The most effective concentrations of ASC, PAA, and NaOCl treatments resulted in mean microbial population reductions of 2.65, 1.46, and 0.66 log units, respectively. Overall, physical removal of excess dirt appeared to have the greatest effect on the microbial population reductions of postharvest in-shell hazelnuts, and adherence to shells during dry weather appeared to increase the chemical resistance of microorganisms. Future sanitation experiments should consider weather and levels of excess soil on hazelnuts as factors in the apparent efficacy of chemical sanitizers. Testing chemical sanitizers against tightly-adhered Salmonella cells provided consistent results with clear demonstration of chemical efficacies. Acidified sodium chlorite at 1013 ppm was significantly more effective at reducing Salmonella populations than other treatments and shows the greatest potential for use as a postharvest sanitation treatment. Thorough rinsing of hazelnuts in clean tap water, followed by spraying with high concentrations of acidified sodium chlorite could help increase the efficacy of current hazelnut processing. Title: Efficacy of water, sodium hypochlorite, peroxyacetic acid, and acidified sodium chlorite for reducing microorganisms on in-shell hazelnuts Author: Weller, Lisa D. Hazelnuts are commonly consumed raw and are valued for their numerous health benefits and antioxidant properties. Increased foodborne illness outbreaks associated with Salmonella and Escherichia coli O157:H7 contamination of tree nuts and peanuts generate a need for improving agricultural sanitation procedures. Food-safe chemical sanitizers have shown promise for reducing pathogenic organisms on fresh produce, but minimal research has been conducted for in-shell nuts. The purpose of this study was to determine the effects of water and three food-safe sanitizers on a) the natural microbial load of postharvest in-shell hazelnuts and b) populations of pathogenic Salmonella (S. enterica subsp. enterica ser. Panama) inoculated and dried onto the surfaces of in-shell hazelnuts. The first phase of the study investigated the effectiveness of water, sodium hypochlorite (NaOCl; 25 ppm, 50 ppm), peroxyacetic acid (PAA; 80 ppm, 120 ppm), and acidified sodium chlorite (ASC; 990 ppm) as sanitizers for use on postharvest in-shell hazelnuts. Treatments were applied to two groups of freshly harvested hazelnut samples to examine their effects on total aerobic microorganism populations during different times of harvest (Group 1 = early season, dry weather; Group 2 = late season, rainy weather). Treatments within each group included hazelnuts that underwent a tap water rinse, a tap water rinse followed by a water spray, and a tap water rinse followed by a chemical spray. Due to excess soil attached to shell surface, hazelnuts harvested later in the season (Group 2) had an initial population mean 2.24 log CFU/hazelnut greater than hazelnuts harvested earlier in the season (Group 1). All treatments, including water, resulted in significant population reductions compared to untreated controls (P≤0.05). Rinsing with tap water produced reductions of 0.38 log units in both groups, and additional water spraying resulted in reductions of 0.83 and 0.73 log units in Group 1 and Group 2, respectively. None of the chemical treatments were significantly more effective than the water spray treatment in Group 1; however, several chemical treatments in Group 2 were significantly more effective than water spraying. Tight adherence to shell surfaces during dry weather may have increased the chemical resistance of microorganisms on hazelnuts. Treatment with ASC produced the greatest reduction in Group 1 and Group 2 compared to the control (1.22 and 2.08 log units, respectively) and water spray treatments (0.39 and 1.39 log units, respectively), but the efficacies varied between treatment groups. Wide variation between Group 1 and Group 2 treatment results made determination of chemical efficacy difficult. The second phase of the study analyzed the effectiveness of water, sodium hypochlorite (NaOCl; 25 ppm, 50 ppm), peroxyacetic acid (PAA; 80 ppm, 120 ppm), and acidified sodium chlorite (ASC; 450 ppm, 830 ppm, 1013 ppm) as sanitizers for reducing Salmonella on in-shell hazelnuts. Hazelnut samples were soaked in pure cultures of S. Panama for 24 h, air dried for 66 h, and then sprayed with water and chemical treatments. Surviving S. Panama populations were evaluated using a non-selective medium (tryptic soy agar), followed by a selective overlay (xylose lysine deoxycholate agar) after a 3 h incubation period. Tight adhesion prevented significant population decreases from physical removal by water, which allowed for clear demonstration of chemical effectiveness. All of the chemical treatments significantly reduced the S. Panama population (P≤0.05) compare to untreated and water-sprayed samples. The most effective concentrations of ASC, PAA, and NaOCl treatments resulted in mean microbial population reductions of 2.65, 1.46, and 0.66 log units, respectively. Overall, physical removal of excess dirt appeared to have the greatest effect on the microbial population reductions of postharvest in-shell hazelnuts, and adherence to shells during dry weather appeared to increase the chemical resistance of microorganisms. Future sanitation experiments should consider weather and levels of excess soil on hazelnuts as factors in the apparent efficacy of chemical sanitizers. Testing chemical sanitizers against tightly-adhered Salmonella cells provided consistent results with clear demonstration of chemical efficacies. Acidified sodium chlorite at 1013 ppm was significantly more effective at reducing Salmonella populations than other treatments and shows the greatest potential for use as a postharvest sanitation treatment. Thorough rinsing of hazelnuts in clean tap water, followed by spraying with high concentrations of acidified sodium chlorite could help increase the efficacy of current hazelnut processing. Close

• 13096. [Article] Activity, composition and structure of soil microbial communities in Savannah shrubs of agroecosystems in semi-arid Senegal

  Piliostigma reticulatum and Guiera senegalensis are two native shrubs that coexist with row crops in parkland systems of the Sahel of Africa. Although permanently green all year around in soil depleted ...

  Citation × Citation Citation Abstract Copy Title: Activity, composition and structure of soil microbial communities in Savannah shrubs of agroecosystems in semi-arid Senegal Author: Diedhiou, Sire Piliostigma reticulatum and Guiera senegalensis are two native shrubs that coexist with row crops in parkland systems of the Sahel of Africa. Although permanently green all year around in soil depleted in nutrients and dry for a nine-month period, these shrubs have been largely overlooked. Conventional management of these shrubs involves coppicing and burning of aboveground biomass each spring to prepare for the summer cropping season. Previous research has shown these shubs can provide high amount of biomass carbon at landscape levels and that they can, through their roots, move water from the wet subsoil to the dry surface soil at night when photosynthesis stops (hydraulic redistribution). However, the influence of these shrubs on the soil microbial communities and their role in biogeochemical processes is largely unknown. This dissertation reports studies that have been carried out to investigate the impact of these shrubs on the soil microbial communities. The rhizosphere effect of these two dominant shrubs was investigated during both the rainy season and dry season by studying the soil microbial structure, composition and activity. This was done by: 1) profiling microbial communities through phospholipids fatty acid (PLFA) analysis and denaturing gradient gel electrophoresis (DGGE); 2) assaying enzymes (acid phosphatase, β-glucosidase, cellulase, chitinase, urease); and 3) measuring microbial biomass carbon (MBC) and mineral nitrogen dynamics. Decomposition studies were conducted to determine the potential of nonthermal management of shrub residues. This was done by determining the influence of shrub canopy, macrofauna, and residue type on shrub litter decomposition and microbial dynamics under field and laboratory conditions. Microbial communities were more diverse, more active and had greater biomass in shrub rhizospheres. The rhizosphere communities during the dry season were similar to the rhizosphere and bulk communities during the wet season. This suggests that shrub rhizosphere provide root exudates and/or water via hydraulic redistribution that supports microbial communities during the dry season. PLFA and enzyme activities were highly correlated and were more sensitive than DGGE in distinguishing the communities temporally and spatially. PLFA profiling showed that the rhizosphere effect was dominated by fungi and Gram-positive bacteria communities, and stimulated acid phosphatase and β-glucosidase activities. Macrofauna access to shrub residue resulted in higher decomposition rates with 70 to 90% loss of mass after 210 days. There was an increase of MBC and enzyme activities when macrofauna were allowed, and beneath shrub canopy as opposed to outside of the canopy. In a laboratory incubation study, the influence of shrub rhizosphere/canopy on soil was greater than the residue effect on the activity of soil microbial communities. Decomposition of residues showed that leaf litter had a greater impact on soil microbial communities and enzyme activities than did stem materials or stem/leaf mixes. Cellulase and β-glucosidase were highly correlated with the fungal markers and Gram-positive bacteria markers. In conclusion, the results showed that Piliostigma reticulatum and Guiera senegalensis are stimulating microbial activity and communities even in the dry season after six or more months without rainfall. Besides C inputs through litter fall, root turnover and exudates, this suggests that shrubs maintain moisture levels in the dry season for microorganisms by performing hydraulic redistribution of water from wet subsoils to dry surface soils at night through a passive water potential gradient. Consequently, shrubs are maintaining soil health and can drive biogeochemical processes year round which has not been previously recognized. These results provide a foundation to actively manage these shrubs to conserve Sahelian landscapes and to optimize agricultural productivity. Title: Activity, composition and structure of soil microbial communities in Savannah shrubs of agroecosystems in semi-arid Senegal Author: Diedhiou, Sire Piliostigma reticulatum and Guiera senegalensis are two native shrubs that coexist with row crops in parkland systems of the Sahel of Africa. Although permanently green all year around in soil depleted in nutrients and dry for a nine-month period, these shrubs have been largely overlooked. Conventional management of these shrubs involves coppicing and burning of aboveground biomass each spring to prepare for the summer cropping season. Previous research has shown these shubs can provide high amount of biomass carbon at landscape levels and that they can, through their roots, move water from the wet subsoil to the dry surface soil at night when photosynthesis stops (hydraulic redistribution). However, the influence of these shrubs on the soil microbial communities and their role in biogeochemical processes is largely unknown. This dissertation reports studies that have been carried out to investigate the impact of these shrubs on the soil microbial communities. The rhizosphere effect of these two dominant shrubs was investigated during both the rainy season and dry season by studying the soil microbial structure, composition and activity. This was done by: 1) profiling microbial communities through phospholipids fatty acid (PLFA) analysis and denaturing gradient gel electrophoresis (DGGE); 2) assaying enzymes (acid phosphatase, β-glucosidase, cellulase, chitinase, urease); and 3) measuring microbial biomass carbon (MBC) and mineral nitrogen dynamics. Decomposition studies were conducted to determine the potential of nonthermal management of shrub residues. This was done by determining the influence of shrub canopy, macrofauna, and residue type on shrub litter decomposition and microbial dynamics under field and laboratory conditions. Microbial communities were more diverse, more active and had greater biomass in shrub rhizospheres. The rhizosphere communities during the dry season were similar to the rhizosphere and bulk communities during the wet season. This suggests that shrub rhizosphere provide root exudates and/or water via hydraulic redistribution that supports microbial communities during the dry season. PLFA and enzyme activities were highly correlated and were more sensitive than DGGE in distinguishing the communities temporally and spatially. PLFA profiling showed that the rhizosphere effect was dominated by fungi and Gram-positive bacteria communities, and stimulated acid phosphatase and β-glucosidase activities. Macrofauna access to shrub residue resulted in higher decomposition rates with 70 to 90% loss of mass after 210 days. There was an increase of MBC and enzyme activities when macrofauna were allowed, and beneath shrub canopy as opposed to outside of the canopy. In a laboratory incubation study, the influence of shrub rhizosphere/canopy on soil was greater than the residue effect on the activity of soil microbial communities. Decomposition of residues showed that leaf litter had a greater impact on soil microbial communities and enzyme activities than did stem materials or stem/leaf mixes. Cellulase and β-glucosidase were highly correlated with the fungal markers and Gram-positive bacteria markers. In conclusion, the results showed that Piliostigma reticulatum and Guiera senegalensis are stimulating microbial activity and communities even in the dry season after six or more months without rainfall. Besides C inputs through litter fall, root turnover and exudates, this suggests that shrubs maintain moisture levels in the dry season for microorganisms by performing hydraulic redistribution of water from wet subsoils to dry surface soils at night through a passive water potential gradient. Consequently, shrubs are maintaining soil health and can drive biogeochemical processes year round which has not been previously recognized. These results provide a foundation to actively manage these shrubs to conserve Sahelian landscapes and to optimize agricultural productivity. Close

• 13097. [Article] Certain genetic and maternal environmental influences on growth rate and body composition of lambs

  The present study was designed to investigate the relationship of milk production and milk quality to growth rate and certain organ-oleptic measurements of lambs of mutton breeds, Nine mature ewes in their ...

  Citation × Citation Citation Abstract Copy Title: Certain genetic and maternal environmental influences on growth rate and body composition of lambs Author: Addleman, Albert Duane The present study was designed to investigate the relationship of milk production and milk quality to growth rate and certain organ-oleptic measurements of lambs of mutton breeds, Nine mature ewes in their fourth lactation of the Border Cheviot, Dorset Horn, Columbia, Suffolk, and Willamette breeds were acquired making a total of 45 ewes. An attempt was made to synchronize parturition, The reason for synchronizing parturition was to have all the ewes lamb during a narrow interval of days so that milk production and its effects on growth could be measured under environmental conditions that were as similar as possible. The ewes were milked by use of oxytocin to cause them to eject the milk in the udder after which they were kept separate from their lambs for six hours and milked again. The milk obtained for the six-hour period was weighed and the quantity recorded. A representative sample was taken from milk of each ewe for composition analyses. The average percentage composition of the milk from ewes was found to be: protein, 5.46; lactose + ash, 5.40; solids-not-fat, 10.86; fat, 8.43, total solids, 19.29; and water, 80.71. There were no significant differences (P >.05) between breeds for the percentage of milk components studied. During the first eight weeks of lactation the breeds studied had produced 74 percent and by ten weeks they had produced 87 percent of the milk yield for the total lactation period. The breeds ranked in the following order on the basis of milk yield and milk quality: Suffolk, Willamette, Dorset Horn, Border Cheviot, and Columbia. The latter two breeds were approximately equal. Ewes nursing twin lambs produced 25 percent more milk than ewes nursing single lambs, The peak of lactation occurred in the third and fourth weeks of lactation, The average grams of milk produced per day for ewes nursing single and twin lambs, respectively, are as follows for the five breeds: Border Cheviot 1, 016, 1, 669; Dorset Horn 1, 617, 1, 778; Columbia 1,366, 1,684; Suffolk 1,527, 2,287; and Willamette 1, 552, 1, 951. A set of twins gained on the average 40.7 percent more than a single lamb. Single lambs gained 15.7 percent rnore weight than the average of a set of twins. The Willamette had the highest average daily gain and was followed in order by the Suffolk, Columbia, Dorset Horn, and Border Cheviot. The average grams of milk consumed for each gram of gain for single and twin lambs, respectively, are as follows; Border Cheviot 3.964, 3.455; Dorset Horn 5.472, 3.424; Columbia 4.406, 3.716; Suffolk 4.326, 3.882; and Willamette 4.193, 3.114. It was concluded that a large portion of the nutrients required for lamb growth and fattening must be supplied by foods other than milk. Highly significant differences among breeds of sheep (P <.01) were found to exist for weaning weight. Weight differences between sexes within a breed were not significant, and there appeared to be no significant interaction between breed and sex. A correlation coefficient of 0.84 between total gain of the lamb and total grams of milk produced by its dam was highly significant. Seventy percent of the variation in total gain is accounted for by variation in total milk yield. The breeds ranked in the following order for carcass tenderness and composite preference of meat; Columbia, Willamette, Dorset Horn, Border Cheviot, and Suffolk. It was postulated that lamb weight at eight to ten weeks of age would be a better criterion by which to cuIl low producing ewes and to select replacement females and males than the 120-day weight. The conformation score, composite preference score, tenderness score, and the percentage of protein, solids-not-fat, milk fat, and total days nursed, were not affected by the breed, sex or rearing of the lambs studied. Only 100-day weight and condition scores were affected by breed. Total gain of the lamb was affected by the quantity of milk and milk components produced by the dam. Title: Certain genetic and maternal environmental influences on growth rate and body composition of lambs Author: Addleman, Albert Duane The present study was designed to investigate the relationship of milk production and milk quality to growth rate and certain organ-oleptic measurements of lambs of mutton breeds, Nine mature ewes in their fourth lactation of the Border Cheviot, Dorset Horn, Columbia, Suffolk, and Willamette breeds were acquired making a total of 45 ewes. An attempt was made to synchronize parturition, The reason for synchronizing parturition was to have all the ewes lamb during a narrow interval of days so that milk production and its effects on growth could be measured under environmental conditions that were as similar as possible. The ewes were milked by use of oxytocin to cause them to eject the milk in the udder after which they were kept separate from their lambs for six hours and milked again. The milk obtained for the six-hour period was weighed and the quantity recorded. A representative sample was taken from milk of each ewe for composition analyses. The average percentage composition of the milk from ewes was found to be: protein, 5.46; lactose + ash, 5.40; solids-not-fat, 10.86; fat, 8.43, total solids, 19.29; and water, 80.71. There were no significant differences (P >.05) between breeds for the percentage of milk components studied. During the first eight weeks of lactation the breeds studied had produced 74 percent and by ten weeks they had produced 87 percent of the milk yield for the total lactation period. The breeds ranked in the following order on the basis of milk yield and milk quality: Suffolk, Willamette, Dorset Horn, Border Cheviot, and Columbia. The latter two breeds were approximately equal. Ewes nursing twin lambs produced 25 percent more milk than ewes nursing single lambs, The peak of lactation occurred in the third and fourth weeks of lactation, The average grams of milk produced per day for ewes nursing single and twin lambs, respectively, are as follows for the five breeds: Border Cheviot 1, 016, 1, 669; Dorset Horn 1, 617, 1, 778; Columbia 1,366, 1,684; Suffolk 1,527, 2,287; and Willamette 1, 552, 1, 951. A set of twins gained on the average 40.7 percent more than a single lamb. Single lambs gained 15.7 percent rnore weight than the average of a set of twins. The Willamette had the highest average daily gain and was followed in order by the Suffolk, Columbia, Dorset Horn, and Border Cheviot. The average grams of milk consumed for each gram of gain for single and twin lambs, respectively, are as follows; Border Cheviot 3.964, 3.455; Dorset Horn 5.472, 3.424; Columbia 4.406, 3.716; Suffolk 4.326, 3.882; and Willamette 4.193, 3.114. It was concluded that a large portion of the nutrients required for lamb growth and fattening must be supplied by foods other than milk. Highly significant differences among breeds of sheep (P <.01) were found to exist for weaning weight. Weight differences between sexes within a breed were not significant, and there appeared to be no significant interaction between breed and sex. A correlation coefficient of 0.84 between total gain of the lamb and total grams of milk produced by its dam was highly significant. Seventy percent of the variation in total gain is accounted for by variation in total milk yield. The breeds ranked in the following order for carcass tenderness and composite preference of meat; Columbia, Willamette, Dorset Horn, Border Cheviot, and Suffolk. It was postulated that lamb weight at eight to ten weeks of age would be a better criterion by which to cuIl low producing ewes and to select replacement females and males than the 120-day weight. The conformation score, composite preference score, tenderness score, and the percentage of protein, solids-not-fat, milk fat, and total days nursed, were not affected by the breed, sex or rearing of the lambs studied. Only 100-day weight and condition scores were affected by breed. Total gain of the lamb was affected by the quantity of milk and milk components produced by the dam. Close

• 13098. [Article] Effects of pollen collected by honey bees from pollination dependent agricultural cropping systems on honey bee nutrition

  Managed honey bee (Apis mellifera L.) colonies are important pollinators of many cultivated crops. Honey bee colony declines averaging 30% annually in the United States for the past 7 years have caused ...

  Citation × Citation Citation Abstract Copy Title: Effects of pollen collected by honey bees from pollination dependent agricultural cropping systems on honey bee nutrition Author: Topitzhofer, Ellen Managed honey bee (Apis mellifera L.) colonies are important pollinators of many cultivated crops. Honey bee colony declines averaging 30% annually in the United States for the past 7 years have caused significant concern and hence have been a topic of intensive investigation. These declines are reportedly due to multiple factors. Poor nutrition, which may be a result of current migratory pollination practices, is one such factor. Migratory pollination is a common practice of beekeepers from the Pacific Northwest and involves the placement of managed honey bee colonies within a series of cropping systems. There is a gap in knowledge on how migratory pollination practices impact honey bee nutrition. To understand the potential impacts of migratory pollination on honey bee nutrition, it is critical to assess the diversity of pollen collected by bees when colonies are placed adjacent to these cropping systems. In this study, we describe the diversity of pollen collected by honey bee colonies managed by beekeepers in the Pacific Northwest region of the United States when placed in seven major cropping systems. We quantified the percent of target crop pollen and overall diversity of pollen collected by honey bees when colonies were placed in these cropping systems. We collected and identified pollen in almond (Prunus dulcis (Mill.)), cherry (Prunus avium L.), highbush blueberry (Vaccinium corymbosum L.), meadowfoam (Limnanthes alba Benth.), white clover (Trifolium repens L.), radish (Raphanus sativus L.), and carrot (Daucus carota (Hoffm.)) cropping systems. We found that pollen collected from colonies placed in almond cropping systems was predominately Prunus sp., and hence, low in pollen diversity. At the other end of the spectrum, pollen collected from colonies placed adjacent to blueberry cropping systems did not yield any target pollen types (Highbush blueberry, Vaccinium corymbosum L.), but was high in overall pollen diversity. The pollen collected from colonies placed in other cropping systems was largely intermediate in diversity between these two extremes. There were not many plant species in bloom when pollen was collected from colonies placed in almond cropping system, whereas more plants were in bloom when we collected pollen from colonies placed in blueberry cropping system. The results of this study demonstrate that honey bees collected pollen from plants in the surrounding environment and collected different degrees of pollen diversity across different cropping systems in which the colonies were placed. We further determined if pollen diversity influences colony-level protein utilization and biosynthesis of protein in nurse bees by conducting a pollen feeding experiment. Pollen collected from four different cropping systems in the first study was used to formulate four different diets, each varying in pollen diversity. We measured protein consumption in experimental colonies and by sampling nurse bees from each colony to estimate hypopharyngeal gland protein content and proteolytic enzyme activity after five weeks of feeding on the experimental pollen diets. Experimental colonies fed on pollen collected from almond cropping system exhibited a high protein consumption rate. However, low protein content as found in hypopharyngeal glands of nurse bees in these colonies. The nurse bees in these colonies also had low proteolytic enzyme activity, which indicates a lower rate of protein digestion. Overall, these results suggest that the diet representing pollen collected from almond cropping systems had low digestion rate and may have resulted in lower nurse bee hypopharyngeal gland protein. However, we cannot say this with certainty, as there were other confounding factors involved, such as presence of pesticides in the pollen collected from the cropping systems. Title: Effects of pollen collected by honey bees from pollination dependent agricultural cropping systems on honey bee nutrition Author: Topitzhofer, Ellen Managed honey bee (Apis mellifera L.) colonies are important pollinators of many cultivated crops. Honey bee colony declines averaging 30% annually in the United States for the past 7 years have caused significant concern and hence have been a topic of intensive investigation. These declines are reportedly due to multiple factors. Poor nutrition, which may be a result of current migratory pollination practices, is one such factor. Migratory pollination is a common practice of beekeepers from the Pacific Northwest and involves the placement of managed honey bee colonies within a series of cropping systems. There is a gap in knowledge on how migratory pollination practices impact honey bee nutrition. To understand the potential impacts of migratory pollination on honey bee nutrition, it is critical to assess the diversity of pollen collected by bees when colonies are placed adjacent to these cropping systems. In this study, we describe the diversity of pollen collected by honey bee colonies managed by beekeepers in the Pacific Northwest region of the United States when placed in seven major cropping systems. We quantified the percent of target crop pollen and overall diversity of pollen collected by honey bees when colonies were placed in these cropping systems. We collected and identified pollen in almond (Prunus dulcis (Mill.)), cherry (Prunus avium L.), highbush blueberry (Vaccinium corymbosum L.), meadowfoam (Limnanthes alba Benth.), white clover (Trifolium repens L.), radish (Raphanus sativus L.), and carrot (Daucus carota (Hoffm.)) cropping systems. We found that pollen collected from colonies placed in almond cropping systems was predominately Prunus sp., and hence, low in pollen diversity. At the other end of the spectrum, pollen collected from colonies placed adjacent to blueberry cropping systems did not yield any target pollen types (Highbush blueberry, Vaccinium corymbosum L.), but was high in overall pollen diversity. The pollen collected from colonies placed in other cropping systems was largely intermediate in diversity between these two extremes. There were not many plant species in bloom when pollen was collected from colonies placed in almond cropping system, whereas more plants were in bloom when we collected pollen from colonies placed in blueberry cropping system. The results of this study demonstrate that honey bees collected pollen from plants in the surrounding environment and collected different degrees of pollen diversity across different cropping systems in which the colonies were placed. We further determined if pollen diversity influences colony-level protein utilization and biosynthesis of protein in nurse bees by conducting a pollen feeding experiment. Pollen collected from four different cropping systems in the first study was used to formulate four different diets, each varying in pollen diversity. We measured protein consumption in experimental colonies and by sampling nurse bees from each colony to estimate hypopharyngeal gland protein content and proteolytic enzyme activity after five weeks of feeding on the experimental pollen diets. Experimental colonies fed on pollen collected from almond cropping system exhibited a high protein consumption rate. However, low protein content as found in hypopharyngeal glands of nurse bees in these colonies. The nurse bees in these colonies also had low proteolytic enzyme activity, which indicates a lower rate of protein digestion. Overall, these results suggest that the diet representing pollen collected from almond cropping systems had low digestion rate and may have resulted in lower nurse bee hypopharyngeal gland protein. However, we cannot say this with certainty, as there were other confounding factors involved, such as presence of pesticides in the pollen collected from the cropping systems. Close

• 13099. [Article] The agronomic, economic and social effects of the availability of new weed control treatments to small corn farmers in the North Atlantic Zone of Costa Rica

  The North Atlantic zone of Costa Rica is an alluvial plain, whose fairly good soils and warm, extremely wet climate generate serious weed problems in cultivated crops and pastureland. Basic foods - corn, ...

  Citation × Citation Citation Abstract Copy Title: The agronomic, economic and social effects of the availability of new weed control treatments to small corn farmers in the North Atlantic Zone of Costa Rica Author: McCarty, Thomas Vere The North Atlantic zone of Costa Rica is an alluvial plain, whose fairly good soils and warm, extremely wet climate generate serious weed problems in cultivated crops and pastureland. Basic foods - corn, beans, rice and yuca - are important small farm crops. New land is still being opened for small farming, encouraged by a government-sponsored homesteading program. Research was initiated in 1976 by the International Plant Protection Center, in cooperation with CATIE, to determine whether the weed control practices currently used by small farmers could be improved. Agronomic results indicate that tilling the soil gives no advantage over the farmers present no-tillage methods. Pre-plant treatments with the herbicides glyphosate and paraquat have been shown to save labor in corn crops. There is little evidence that the new treatments raise corn yields. A survey of small farmers was conducted in the region in 1977 and 1978. A random sample of 21 farmers were selected for interviews. The information included a general description of each farm family and the complete farm operation and detailed descriptions of cultural practices in corn and beans crop, with special emphasis on weed control. Social and economic information was also obtained. Small farms in the sample are in various stages of development. The first step is usually to brush out the native timberland and fence off areas for a few cattle to graze. Then parcels are cleared for annual crops, especially corn, which is the most dependable cash crop. The farmer rotates parcels for annual crops, weedy fallow and pasture. He constantly attempts to build up his beef herd. Development of perennial plots is limited by the quantities demanded for home and local use. Nearly half the labor, and half the cash resources, expended in corn production are for weed control. The farmers typically cut the weeds with machete and leave the vegetation as mulch before planting, weed the crop with machete or with very light applications of 2,4-D, and cut the weeds once more with machete before doubling the ears and harvesting. Some temporary local shortages of labor occur in the peak periods, when harvesting for one season overlaps with soil preparation and planting for the next, although general underemployment prevails in the long slack periods. Weed conditions influence greatly the quantities of labor used for weed control. Rottboellia exaltata is the most noxious weed in corn cropping. The quantitative information from the survey was tabulated in partial budgets or detailed accounting sheets of variable costs and revenues, for corn parcels on each sample farm. Analysis of variance and regression models were used to test hypothetical relationships among the variables. These results were then compared with estimated capabilities and costs of the experimental weed control treatments for the corn crop on each sample farm. Reported wage rates and calculated returns to family labor were used to estimate the values of family labor. It was found that a minority of the small corn farmers - those who currently use relatively high quantities of cash resources - might be able to reduce costs with the new treatments, without losing revenue. Their increases in cash income would not always exceed the losses in gainful employment suffered by the farmworkers. For the majority of small farmers in the region - those who raise corn with family labor as the main resource - the new treatments do not appear to offer any economic advantages. The treatments are expensive, they offer little promise for raising yields, and their labor-saving effects do not fall squarely in the peak labor periods. It is suggested, therefore, that recommendation of the new treatments should be subject to the farmers' financial conditions and to their actual objectives in growing corn. The use of soil samples and research in the control of pasture weeds are also suggested for further research by the IPPC. Finally, it is suggested that assistance in the development of extra-local banana markets for small farmers might be of great value. Title: The agronomic, economic and social effects of the availability of new weed control treatments to small corn farmers in the North Atlantic Zone of Costa Rica Author: McCarty, Thomas Vere The North Atlantic zone of Costa Rica is an alluvial plain, whose fairly good soils and warm, extremely wet climate generate serious weed problems in cultivated crops and pastureland. Basic foods - corn, beans, rice and yuca - are important small farm crops. New land is still being opened for small farming, encouraged by a government-sponsored homesteading program. Research was initiated in 1976 by the International Plant Protection Center, in cooperation with CATIE, to determine whether the weed control practices currently used by small farmers could be improved. Agronomic results indicate that tilling the soil gives no advantage over the farmers present no-tillage methods. Pre-plant treatments with the herbicides glyphosate and paraquat have been shown to save labor in corn crops. There is little evidence that the new treatments raise corn yields. A survey of small farmers was conducted in the region in 1977 and 1978. A random sample of 21 farmers were selected for interviews. The information included a general description of each farm family and the complete farm operation and detailed descriptions of cultural practices in corn and beans crop, with special emphasis on weed control. Social and economic information was also obtained. Small farms in the sample are in various stages of development. The first step is usually to brush out the native timberland and fence off areas for a few cattle to graze. Then parcels are cleared for annual crops, especially corn, which is the most dependable cash crop. The farmer rotates parcels for annual crops, weedy fallow and pasture. He constantly attempts to build up his beef herd. Development of perennial plots is limited by the quantities demanded for home and local use. Nearly half the labor, and half the cash resources, expended in corn production are for weed control. The farmers typically cut the weeds with machete and leave the vegetation as mulch before planting, weed the crop with machete or with very light applications of 2,4-D, and cut the weeds once more with machete before doubling the ears and harvesting. Some temporary local shortages of labor occur in the peak periods, when harvesting for one season overlaps with soil preparation and planting for the next, although general underemployment prevails in the long slack periods. Weed conditions influence greatly the quantities of labor used for weed control. Rottboellia exaltata is the most noxious weed in corn cropping. The quantitative information from the survey was tabulated in partial budgets or detailed accounting sheets of variable costs and revenues, for corn parcels on each sample farm. Analysis of variance and regression models were used to test hypothetical relationships among the variables. These results were then compared with estimated capabilities and costs of the experimental weed control treatments for the corn crop on each sample farm. Reported wage rates and calculated returns to family labor were used to estimate the values of family labor. It was found that a minority of the small corn farmers - those who currently use relatively high quantities of cash resources - might be able to reduce costs with the new treatments, without losing revenue. Their increases in cash income would not always exceed the losses in gainful employment suffered by the farmworkers. For the majority of small farmers in the region - those who raise corn with family labor as the main resource - the new treatments do not appear to offer any economic advantages. The treatments are expensive, they offer little promise for raising yields, and their labor-saving effects do not fall squarely in the peak labor periods. It is suggested, therefore, that recommendation of the new treatments should be subject to the farmers' financial conditions and to their actual objectives in growing corn. The use of soil samples and research in the control of pasture weeds are also suggested for further research by the IPPC. Finally, it is suggested that assistance in the development of extra-local banana markets for small farmers might be of great value. Close

• 13100. [Article] Ova tranfers in sheep and rabbits : studies on material influences and irradiation damage

  The first study utilized ova transfer in sheep and involved hormonal treatments for synchronization of estrus and superovulation in an investigation of crossbred maternal influences on inbred and linecross ...

  Citation × Citation Citation Abstract Copy Title: Ova tranfers in sheep and rabbits : studies on material influences and irradiation damage Author: Hunt, William Lynn The first study utilized ova transfer in sheep and involved hormonal treatments for synchronization of estrus and superovulation in an investigation of crossbred maternal influences on inbred and linecross lambs. Synchronization of estrus in ewes was achieved effectively with either oral progestogen, 6 α-methyl-17α-hydroxy-progesterone acetate (60 mg./ewe/day), or intramuscular injections of progesterone (10 mg./ewe/day), Satisfactory superovulation was not obtained with pregnant mare serum preparations and alterations in oviduct morphology were noted following oral progestogen therapy. After progesterone injections, superovulation with a mean of 13.4 ovulations per ewe was obtained using pituitary extracts. Successful treatments began day after final progesterone injection with primary injection of 25 mg. followed in two days with 15 mg. of pituitary extract. An intravenous injection of 25 mg. pituitary leutinizing hormone followed at onset of estrus. Twelve Suffolk ewes of three inbred lines were bred to produce fertilized ova from each of three lines and from each possible linecross. Surgical transfers of ova from Suffolk donors were made to nine recipients which were similar in size and consisted genetically of Columbia, Dorset and Cheviot crosses. Based on corpora lutea numbers, in vivo ova recovery rates increased from 39 percent for the first year to 53 percent for the second year. Cleavage rates were 54 and 52 percent for the two years. The inbred line II lamb which developed in a crossbred maternal environment weighed 12.3 percent more at birth than its non-transfer line II counterpart. The transferred linecross III x II lamb weighed 30.6 percent more at birth than its non-transfer counterpart. The linecross took most advantage of prenatal nutrition. Adjusted 120-day weights, condition and conformation scores were similar for transfer and non-transfer lambs at weaning. Under similar postnatal environment, genotype for size is expressed in lambs at weaning. In the second study effects of in vitro x-irradiation of fertilized mammalian ova on their subsequent in vivo development were investigated by means of rabbit ova transfer. Non-irradiated and irradiated two-cell ova were transferred to non-irradiated and irradiated uteri of recipients to discriminate between embryonic and uterine injury. Irradiation was applied to two-cell ova in vitro at levels of 0, 15.4, 61.2, 91.8, and 122.5 rads using a 100 kVp x-ray machine (1 ma., HVL 1 mm. Al., distance 37.4 cm., dose 14.5 r./min.), Ova were transferred into oviducts of prepared recipients. Uteri of recipients were exposed to the same radiation levels as the ova and in addition to 250.2, 265.3, and 530.5 rads. Combination of ova/uterus irradiation showed additive effects of x-ray damage. One step increases of either ova or uterus above 61.2/250.3 rads caused 100 percent embryo mortality Two-cell ova which were given 122.5 rads of irradiation failed to develop into fetuses and uteri which were given 530.5 rads failed to contain implantations. Irradiation with 91.8 rads killed all but the most hardy ova and produced an all or none effect, while 61.2 rads caused abnormal, dead, and resorbed fetuses as well as living offspring. Two such newborn developed latent sequelae in the form of spreading limbs. Deformities became obvious at one month and progressed until death at four months. Histological examinations of eight-day embryos which received 61.2 rads or no irradiation as two-cell ova revealed delayed development in irradiated embryos. Mean spring from increase in weight for the first 50 days of surviving off-spring from irradiated ova was 6 gms./day more than that of controls. Title: Ova tranfers in sheep and rabbits : studies on material influences and irradiation damage Author: Hunt, William Lynn The first study utilized ova transfer in sheep and involved hormonal treatments for synchronization of estrus and superovulation in an investigation of crossbred maternal influences on inbred and linecross lambs. Synchronization of estrus in ewes was achieved effectively with either oral progestogen, 6 α-methyl-17α-hydroxy-progesterone acetate (60 mg./ewe/day), or intramuscular injections of progesterone (10 mg./ewe/day), Satisfactory superovulation was not obtained with pregnant mare serum preparations and alterations in oviduct morphology were noted following oral progestogen therapy. After progesterone injections, superovulation with a mean of 13.4 ovulations per ewe was obtained using pituitary extracts. Successful treatments began day after final progesterone injection with primary injection of 25 mg. followed in two days with 15 mg. of pituitary extract. An intravenous injection of 25 mg. pituitary leutinizing hormone followed at onset of estrus. Twelve Suffolk ewes of three inbred lines were bred to produce fertilized ova from each of three lines and from each possible linecross. Surgical transfers of ova from Suffolk donors were made to nine recipients which were similar in size and consisted genetically of Columbia, Dorset and Cheviot crosses. Based on corpora lutea numbers, in vivo ova recovery rates increased from 39 percent for the first year to 53 percent for the second year. Cleavage rates were 54 and 52 percent for the two years. The inbred line II lamb which developed in a crossbred maternal environment weighed 12.3 percent more at birth than its non-transfer line II counterpart. The transferred linecross III x II lamb weighed 30.6 percent more at birth than its non-transfer counterpart. The linecross took most advantage of prenatal nutrition. Adjusted 120-day weights, condition and conformation scores were similar for transfer and non-transfer lambs at weaning. Under similar postnatal environment, genotype for size is expressed in lambs at weaning. In the second study effects of in vitro x-irradiation of fertilized mammalian ova on their subsequent in vivo development were investigated by means of rabbit ova transfer. Non-irradiated and irradiated two-cell ova were transferred to non-irradiated and irradiated uteri of recipients to discriminate between embryonic and uterine injury. Irradiation was applied to two-cell ova in vitro at levels of 0, 15.4, 61.2, 91.8, and 122.5 rads using a 100 kVp x-ray machine (1 ma., HVL 1 mm. Al., distance 37.4 cm., dose 14.5 r./min.), Ova were transferred into oviducts of prepared recipients. Uteri of recipients were exposed to the same radiation levels as the ova and in addition to 250.2, 265.3, and 530.5 rads. Combination of ova/uterus irradiation showed additive effects of x-ray damage. One step increases of either ova or uterus above 61.2/250.3 rads caused 100 percent embryo mortality Two-cell ova which were given 122.5 rads of irradiation failed to develop into fetuses and uteri which were given 530.5 rads failed to contain implantations. Irradiation with 91.8 rads killed all but the most hardy ova and produced an all or none effect, while 61.2 rads caused abnormal, dead, and resorbed fetuses as well as living offspring. Two such newborn developed latent sequelae in the form of spreading limbs. Deformities became obvious at one month and progressed until death at four months. Histological examinations of eight-day embryos which received 61.2 rads or no irradiation as two-cell ova revealed delayed development in irradiated embryos. Mean spring from increase in weight for the first 50 days of surviving off-spring from irradiated ova was 6 gms./day more than that of controls. Close