Risk of gene introgression from transgenic wheat to jointed goatgrass

Department Head: Gary Peterson.2010 Summer.Includes bibliographical references (pages 95-97).To view the abstract, please see the full text of the document

Adaptability of a daily disaggregation model to the midwestern United States

A daily disaggregation model developed with summer rainfall data from southeastern Arizona was analyzed for its utility at two midwestern locations, Hastings, Nebraska, and McCredie, Missouri. The model required modification. For example, two distributions required modification and one was replaced. An addition to the model was made to describe the diurnal variation in shower depth for days with one shower. With modifications, the disaggregation model accurately described the daily intermittant rainfall process for the two midwestern locations. Parameter values developed from the Hastings and McCredie's (primary stations) data sets were used to simulate the daily intermittent rainfall at three nearby locations (test stations). Statistical testing indicated that the primary stations' parameter values adaquately simulated the test stations rainfall if the stations were within the same precipitation c1imatologic zone.hydrology collectio

CONSTRUCTING WHEAT DIFFERENTIATION IN WESTERN WASHINGTON AGRICULTURE AND FOOD SYSTEMS

Grains, such as wheat (Triticum aestivum L.), are vital components of total farm productivity in western Washington; however, the monetary return of wheat production has been low historically. Increased demand for value-added grain-based products for human consumption, such as regionally produced, nutritionally enhanced, and artisan quality wheat products, can offer farmers an opportunity to sell into higher value markets than current commodity streams. Meeting that demand requires appropriate varieties, best crop management practices, consistent supply, and often new infrastructure and distribution networks. The dissertation adds to the body of work that seeks to understand and develop these differentiated wheat products and systems. Chapter 1 places value-added wheat production into the context of the disappearing agriculture of the middle emphasizing the benefits and challenges of production and products differentiated by social, environmental, and wheat quality characteristics. Chapter 2 identifies unique germplasm from a collection of Nordic wheat accessions containing wildtype NAM-B1 for the development of early maturing high quality hard red spring wheat varieties for western Washington and the Alaska Interior; time to wheat senescence is shown to correlate negatively with yield and positively with grain protein, iron, and zinc content. Chapter 3 reports the limited improvement in wheat quality via grain aging, suggesting that new, small, and midsized mills without controlled storage facilities prioritize blending of varieties and source location to achieve quality consistency. The last two chapters explore the mechanism by which scientists can understand their own personal biases and those of the larger research community. Chapter 4 centers on Jean-Michel Basquiat’s drawing, Untitled (Charles Darwin) 1983, to illustrate how art can reveal biases in the sciences, such as positivism and scientism, and of individual scientists, such as proletarianism and the ideal of autonomy. Chapter 5 analyzes women in genetics and the US Midwest farm in the 20th century revealing the ideal of the family and the tension between exploitation and empowerment for women in science and agriculture. In total the dissertation adds to the research necessary for development of differentiated wheat systems in areas outside major production areas and the underlying assumptions of the research

Blackshot: An unexpected dimension of human sensitivity to contrast

Purpose. We studied the perceptual segregation of texture pairs consisting of a grid of uniform, square texture elements, differing only in the distribution of intensities across those elements. If two textures differ in mean intensity ("lightness") or in the variance of intensity ("contrast"), then they are easily segregated. Chubb, Econopouly & Landy (JOSA A, 11, 2350, 1994) demonstrated the existence of a 3rd mechanism B (in addition to mechanisms L and C, coding lightness and contrast respectively) that was solely responsible for the segregation of textures equated for mean and contrast. Here, we determine the sensitivity of B to textures differing in mean or variance, thus fully specifying its (highly nonlinear) contrast response function. Method. Two textures have gray-level histograms H1 and H2 chosen so as to equate both mean and variance so that B alone discriminates them. The magnitude of the difference D=H1-H2 was varied to find a segregation threshold t*D. Then, D was perturbed (e.g., D'=t*D+P) so that the two textures differed in mean or variance, and segregation performance was assessed. Results. Differences in texture mean and in texture variance traded off linearly with changes in D. This implies that even when the textures differ slightly in mean or variance, it is still B alone that discriminates between them. The slopes of the lines relating changes in mean and variance to changes in the amplitude of D reflect the sensitivity of B to texture mean and variance. Combining these findings with our previous results reveals that B is (i) highly sensitive to texture elements of the lowest contrast (near -1), and (ii) has a response that saturates by a contrast of -3/4 (dark gray). That is, this "blackshot mechanism" discriminates textures by comparing the number of the blackest pixels in each

Blackshot: An unexpected dimension of human sensitivity to contrast

Purpose. We studied the perceptual segregation of texture pairs consisting of a grid of uniform, square texture elements, differing only in the distribution of intensities across those elements. If two textures differ in mean intensity ("lightness") or in the variance of intensity ("contrast"), then they are easily segregated. Chubb, Econopouly & Landy (JOSA A, 11, 2350, 1994) demonstrated the existence of a 3rd mechanism B (in addition to mechanisms L and C, coding lightness and contrast respectively) that was solely responsible for the segregation of textures equated for mean and contrast. Here, we determine the sensitivity of B to textures differing in mean or variance, thus fully specifying its (highly nonlinear) contrast response function. Method. Two textures have gray-level histograms H1 and H2 chosen so as to equate both mean and variance so that B alone discriminates them. The magnitude of the difference D=H1-H2 was varied to find a segregation threshold t*D. Then, D was perturbed (e.g., D'=t*D+P) so that the two textures differed in mean or variance, and segregation performance was assessed. Results. Differences in texture mean and in texture variance traded off linearly with changes in D. This implies that even when the textures differ slightly in mean or variance, it is still B alone that discriminates between them. The slopes of the lines relating changes in mean and variance to changes in the amplitude of D reflect the sensitivity of B to texture mean and variance. Combining these findings with our previous results reveals that B is (i) highly sensitive to texture elements of the lowest contrast (near -1), and (ii) has a response that saturates by a contrast of -3/4 (dark gray). That is, this "blackshot mechanism" discriminates textures by comparing the number of the blackest pixels in each

Adaptability of a Daily Rainfall Disaggregation Model to the Midwestern United States

From the Proceedings of the 1987 Meetings of the Arizona Section - American Water Resources Association, Hydrology Section - Arizona-Nevada Academy of Science and the Arizona Hydrological Society - April 18, 1987, Northern Arizona University, Flagstaff, ArizonaThis article is part of the Hydrology and Water Resources in Arizona and the Southwest collections. Digital access to this material is made possible by the Arizona-Nevada Academy of Science and the University of Arizona Libraries. For more information about items in this collection, contact [email protected]

Abstract A visual mechanism tuned to black

Chubb et al. [Journal of the Optical Society of America A 11 (1994) 2350] investigated preattentive discrimination of achromatic textures comprising random mixtures of 17 Weber contrasts ranging linearly from 1to 1. They showed that only a single mechanism B is used to discriminate between textures whose histograms are equated in mean and in variance. Although they provided a partial characterization of B, their methods did not allow them to measure the sensitivity of B to texture mean and variance. Here, additional measurements are performed to complete the functional characterization of B. The results reveal that B (i) is strongly activated by texture elements of the lowest contrast (near 1), (ii) is slightly activated by texture elements of contrast 0.875, and (iii) barely distinguishes the 15 contrasts ranging from 0.75 all the way up to 1. To reflect the sharpness of its tuning to very dark, sparse elements in a predominantly bright scene, we call B the blackshot mechanism