Now showing items 19972-19991 of 20274


      Ram, Sudha; Liu, Jun; Goes, Paulo; Durcikova, Alexandra (The University of Arizona., 2011)
      Data provenance refers to the lineage or pedigree of data, including information such as its origin and key events that affect it over the course of its lifecycle. In recent years, provenance has become increasingly important as more and more people are using data that they themselves did not generate. Tracking data provenance helps ensure that data provided by many different providers and sources can be trusted and used appropriately. Data provenance also has several other critical uses, including data quality assessment, generating data replication recipes, data security management, etc.One of the major objectives of our research is to investigate the semantics or meaning of data provenance. We describe a generic ontology of data provenance called the W7 model that represents the semantics of data provenance. Formalized in the conceptual graph formalism, the W7 model represents provenance as a combination of seven interconnected elements including "what," "when," "where," "how," "who," "which" and "why." The W7 model is designed to be general and comprehensive enough to cover a broad range of provenance-related vocabularies. However, the W7 model alone, no matter how comprehensive it is, is insufficient for capturing all domain-specific provenance requirements. We hence present a novel approach to developing domain ontologies of provenance. This approach relies on various conceptual graph mechanisms, including schema definitions and canonical formation rules, and enables us to easily adapt and extend the W7 model to develop domain ontologies of provenance. The W7 model for data provenance has been widely adopted and adapted for use within Raytheon Missile Systems and the iPlant Collaborative, as well as the US Army's ATRAP IV (Asymmetric Threat Response and Analysis Program) system.We also developed a domain ontology of provenance for Wikipedia based on the W7 model. This domain ontology enables us to extract provenance for each Wikipedia article. We present a study in which we use their provenance to assess the quality of Wikipedia articles. Assessing and guaranteeing data quality has become a critical concern that, to a large extent, determines the future success and survival of Wikipedia since the quality of Wikipedia has been continuously called into question due to various incidents of vandalism and misinformation since its launch in 2001. Our study shows that the quality of Wikipedia articles depends not only on the different types of contributors but also on how they collaborate. We identify a number of contributor roles based on the provenance. Based on the roles and provenance, our research identifies several collaboration patterns that are preferable or detrimental for data quality, thus providing insights for designing tools and mechanisms to improve Wikipedia article quality.
    • Waimiri Atroari grammar: Some phonological, morphological, and syntactic aspects

      Hill, Jane; Langendoen, Terry; Bruno, Ana Carla (The University of Arizona., 2003)
      The Waimiri Atroari people, who call themselves kinja 'people' and whose language belongs to the Carib family, live today in an area in the northern part of the State of Amazonas and in the southern part of the State of Roraima. Like many other languages of the Carib family, Waimiri Atroari is a chronically underdescribed language. There are few linguistics studies about Waimiri Atroari, most of them being phonological sketches (Hill and Hill 1985; and Lacerda 1991, 1996). Taking this situation into consideration, this dissertation intends to describe some phonological, morphological, and syntactic aspects of the Waimiri Atroari grammar. First, in the introductory chapter I provide some information about their language and culture, and I discuss their experience with formal education. Second, I describe the segmental phonology and analyze the syllable structure and reduplication process under Optimality Theory. Next, I present the word classes and a description of their morphology. Then, I investigate the system of case marking. Finally, in syntax I analyze the phrase structure and the word order under the framework of X-bar theory. The appendices contain a set of verbal paradigms and a collection of texts.

      Lotz, Sherry; Yan, Ruoh-Nan; Lotz, Sherry; Shim, Soyeon; Janakiraman, Narayan (The University of Arizona., 2005)
      Management of consumer waiting experiences is critical for practitioners in that unpleasant waiting experiences may result in negative service evaluations. This study focused on consumers' queue waits during the pre-process phase of waiting experiences, i.e., before services are received, and investigated the extent to which relevant variables during this process may impact consumers' subsequent service experience evaluations. The investigation purported to expand and refine the expectation-affect-service evaluation relationship. Specifically, the framework examined the influence of predicted value of service on wait expectations (conceptualized as "consumer zone of wait tolerance" derived from the service literatures), the effects of consumers' comparisons between wait expectations and perceptions (i.e., wait disconfirmation) and perceived wait duration on affective responses to waiting, and the impact of affective responses to waiting on service experience evaluations. In addition, this study predicted the moderating role of actions of the service provider from a social justice perspective in the relationship between affective response to waiting and service experience evaluation.Data were collected at two points in time (i.e., during waiting and at completion of service) via surveys completed by 393 adult consumers intercepted at three restaurants located in a southwestern city in the U.S. Hypotheses were tested through structural equation modeling, MANCOVA statistical techniques, and additional post hoc analyses. Findings suggest that both wait disconfirmation and perceived wait duration influence service experience evaluation through affective response to waiting. Results also revealed a positive relationship between predicted conditional value and zone of wait tolerance. The study provides support for social exchange theory and better understanding of the role of actions of the service provider in the relationship between affective response to waiting and service experience evaluation. Lastly, post hoc analyses lend credence to the concept that consumers' affective responses to waiting and service experience evaluations vary across the wait disconfirmation groups. Both theoretical and managerial implications are discussed and directions for future research are also provided.
    • Walking the Margin: Gender and Urban Spatial Production in La Paz, Mexico

      Babcock, Barbara A; Tang, Donna Taxco; Babcock, Barbara A; Doxtater, Dennis; Marston, Sallie A.; Alvarez, Maribel (The University of Arizona., 2005)
      This comparison of two urban public spaces in the city of La Paz, Baja California Sur, examines the production of gendered space within an ethnohistorical context of material and discursive practices related to socio-spatial order, cultural and biological reproduction, and the construction of urban scale. The focus of the study of these two “commons” is on the liminal spatiality of the central plaza and the seaside promenade, the role of everyday life and consumption in the production of these spaces, and the role of women in these successive spatial transformations. In order to understand the relations and practices that produce these commons, the various spatial transformations that have affected the southern Baja California Peninsula are described and discussed. It is a place that has been constituted and reconstituted within successive globalizing forces since at least the beginning of the sixteenth century, up to and including contemporary international tourism. The city of La Paz, its people, and its sense of itself as expressed in its public spaces have emerged from these historical and cross-cultural processes. By examining and comparing the Parque Velasco and the Malecón as the products of both past and emerging patterns of spatial discourse in the negotiation, rehearsal and affirmation of gender identities, the following specific questions are addressed: What is the role women play in the cultural production and reproduction of these public spaces in a borderland? How do the spaces differ--materially, discursively, and in usage? What or whose purposes do they serve? How do they position peripheral agents within a hegemonic globalizing process? Finally, the study considers the question of what future can be envisioned for La Paz and its commons as border spaces.
    • Walking Two Worlds: Integrating Lumbee Indian Values and Practices in Education

      Arenas, Alberto; Lucas, Sandy; Arenas, Alberto; Taylor, John; Fox, Mary Jo (The University of Arizona., 2006)
      This study investigates how Lumbee values and practices are integrated in a formal schooling system. A qualitative study was conducted to determine how Lumbee school administrators experience their work, and how Lumbee values and practices are integrated in formal education, and what they thought these values and practices were. The main instruments used to collect data were in-depth interviews and a survey designed by the researcher. The data was collected in Pembroke, North Carolina at the School District's Indian Education Office during 2004 and 2005.The four participants in the study are all Lumbee education administrators, employed with a school district in southeastern North Carolina. Ironically, all four administrators received their undergraduate degrees from the tribe's university, the University of North Carolina at Pembroke, UNCP. The research study focused on the Lumbee tribe, the largest tribe east of the Mississippi river, which has organized the largest Indian education program of any public school district in the United States, with approximately 11,500 Indian students.This is the researcher's personal synthesis of stories and "shared metaphors" that Lumbee Indians hold in common with regard to Tribal education and Indigenous education. This research examines the creative possibilities inherent in the introduction of an Indigenous frame of reference toward the development of a contemporary philosophy of American Indian education. Also, this study explores a "culturally-informed alternative" in education that advocates the development of a contemporary community-based education process, which is founded upon traditional Tribal values, orientations, and principles, but simultaneously utilizes the most appropriate concepts and technologies of modern education. This study offers a creative option for thinking about the evolving expressions of American Indian values and the education of Native American students as they attempt to walk in two worlds, their own and the Non Native.

      Coxon, Moran, 1930- (The University of Arizona., 1971)
    • Wallace Stegner's "Angle of Repose": One reader's response.

      Dryden, Edgar; Hepworth, James Ralph.; Evers, Lawrence; Momaday N. Scott (The University of Arizona., 1989)
      This dissertation reads Wallace Stegner's Angle of Repose by combining objective and subjective critical approaches in an attempt to bridge the gap between storytelling understood formalistically and story in its moving immediacy. The study combines a close textual analysis of the novel with a detailed and extensive account of the critic's personal and emotional responses to it, and these two interpretive perspectives are supplemented by a series of three interviews conducted with the novelist over a period of ten years as well as by an exchange of letters between Stegner and Bernard DeVoto just prior to the publication of Stegner's Beyond the Hundredth Meridian (1951-1953). The study opens with a survey of Stegner's career and argues that his critics have misperceived him as a "regionalist" and undervalued him as a world-class American writer whose work transcends the limitations of place. The ensuing chapters focus on the relationship between the journal form of Angle of Repose and the westering tradition in American letters and on the way the novel situates itself in relation to native American aesthetics and the oral tradition. The burden of these early chapters is to demonstrate that the form of Stegner's novel is symbolic, not only in the formal sense of standing for something other than itself but also in the more subjective sense of figuring the emotional rhythms that it generates in the reader. Later chapters examine in detail the relations between the personal and emotional life of the critic and such technical and thematic issues as unreliable narrator, the Doppelganger motif, and the problems of origins and originality in American fiction. Taken together, the individual chapters are designed to show that Stegner is a postmodern storyteller with postmodern concerns, that he has, in fact, created Angle of Repose as a "counter-subversive novel" by employing the techniques of the so-called "chaos drunk writers" of the 1970's against themselves to produce a work of art that is at once highly original and self-consciously traditional.
    • Wandering Behavior in Manduca Sexta: Investigating Steroid Hormone Effects on Neural Circuits For Locomotor Behavior

      Levine, Richard B.; Miller, Julie Elizabeth; Levine, Richard B.; Tolbert, Leslie P.; Rance, Naomi E.; Yool, Andrea J.; Gruener, Raphael P.; Fregosi, Ralph F. (The University of Arizona., 2005)
      Steroid hormones alter the excitability of neural circuits for motor behavior in vertebrates and invertebrates. The insect Manduca sexta, with its well-characterized developmental and endocrinological history, is a useful model system to study these effects. The wandering behavior is a stage-specific locomotor behavior triggered by the steroid hormone 20-hydroxyecdysone (20E) and consists of crawling and burrowing movements as the animal searches for a pupation site.The results of this dissertation show that 20E acts on the isolated larval nervous system to induce wandering activity. The mechanisms underlying the generation of this activity share features similar to other invertebrate systems, including the presence of segmental central pattern generating circuits. The time course for the nervous system response to 20E is long, suggestive of a genomic mechanism of action, and there are no earlier rapid effects of 20E on the intrinsic membrane properties of the abdominal motoneurons. The site of 20E action in inducing wandering locomotion is unlikely to be the abdominal motoneurons, but interneurons presynaptic to these motoneurons. One possible site of 20E action is the brain, which shows stage-dependent expression of ecdysteroid receptors in certain populations of neurons.Descending regulation by the brain and subesophageal ganglion (SEG) is exerted over the segmental motor circuits for crawling and burrowing and reflects stage-dependent differences. Prior to wandering, the brain exerts inhibition over the segmental motor circuits for crawling, but this inhibition is not present during wandering. Removal of the brain, SEG, and thoracic ganglia during on-going fictive locomotion alters the phase relationships between abdominal segments. Further alterations of fictive crawling motor output are observed in more reduced preparations, indicating the importance of intact connections between abdominal ganglia in the production of a reliable motor program. The SEG drives the fictive burrowing motor program. The burrowing motor program is more robustly expressed in nerve cords from wandering larvae, suggesting a stage-dependent difference due to 20E exposure. Subsequent future experiments will use electrophysiological methods and genetic manipulations in Manduca sexta and Drosophila melanogaster, respectively, to explore target sites for hormone action in the brain and the characterization of brain neurons that drive wandering behavior.
    • War and peace in northern Sung China: Violence and strategy in flux, 960-1104 A.D.

      Tao, Jing-shen; Tsang, Shui-lung, 1960- (The University of Arizona., 1997)
      This dissertation focuses on a critical factor in historical transformation of medieval China-the dilemma between war and peace. Not only does this dissertation provide a brief and comprehensive account on conflicts, battles, and treaties, but it observes the attitude toward violence and the track of searching peace during Tenth and Eleventh Century China as well. Borrowing the concept of peace by modern scholars studying grand strategy, strategic culture, and pacifism, I regard peace as realistic strategic option, institutionalized establishment, consent behavior mode, and multi-oriented culture. My discussion begins with the exhausting campaigns of the T'ang in Central Asia and the ensuing civil war during the Ninth and Tenth centuries, arguing the Sung non-active posture in external adventure as a conscious avoidance of excessive violence. The relative success of the Sung policy saw in the peace annexation of the Wu-Yueh Kingdom and the conclusion of the Peace of 1005 between the Sung and Liao with modest cost. In addition, the early Sung rulers firmly controlled the military machinery and prevented war-making by internal and institutional causes. Nevertheless, the existing institutionalized peace between the Sung and Liao did not create a norm of behavior and prevent violence proliferation. Unable to contain the Tangut expansionism, the Sung was compelled to reinstate aggressive grand strategy, relieving constrain on its war machinery. Strategic imperative stimulated career military service of the Sung civil officials and gave room to the voice of pragmatic expansionism. Sung military achievement culminated in the success of rearmament during the reform of Wang An-shih. However, the ensuing war eventually ravaged the Sung empire, its opportunity for a great leap toward a pre-modern world missed.
    • War and Tolerance: Catholic Polemic in Lyon During the French Religious Wars

      Karant-Nunn, Susan C; Hartley, Brandon; Karant-Nunn, Susan C; Milliman, Paul; Nader, Helen (The University of Arizona., 2007)
      This dissertation studies the content of Catholic polemic printed in the city of Lyon from 1560 to 1594, a period ranging from the first hints of wider Protestant unrest to the submission of the city to Henry IV and the resumption of royal control. The time frame corresponds to an era of zealous Catholic activity in which combating Protestantism, or heresy as they usually labeled it, was a primary focus of the Lyonnaise Catholic Church and the presses which supported it. By studying the thematic content of these cheap print sources, I will provide a glimpse into the types of issues that appear most prominently in this particular type of print medium and trace how such issues change, or remain static, over time. Most important of these themes are the importance of concord or unity and the willingness of God to punish his followers for their sins and, frequently, mankind's unwillingness to reunify the church and create concord through force. This dissertation has grown into a commentary on this dynamic more than any other single issue and readers will detect tangential comments concerning the importance of unity and God's punishment throughout earlier chapters. Time and again, polemicists make clear that the only means to a lasting "peace" is to achieve religious unity by any means necessary. Only this purity within the faithful will ease God's hand and cure France of its ills. Sources were drawn from the principal libraries in Lyon and the Rhone valley, in addition to occasional pieces scattered in Paris and other libraries throughout France.
    • Warden for the Union: General William Hoffman (1807-1884)

      Hunter, Leslie Gene, 1941- (The University of Arizona., 1971)
    • Warning and Deception: Chemical, Behavioral, and Phylogenetic Studies of Aposematic Coloration and Mimicry

      Papaj, Daniel R.; Prudic, Kathleen L.; Papaj, Daniel R.; Bronstein, Judith L.; Becerra, Judith X.; Timmermann, Barbara N. (The University of Arizona., 2007)
      The study of aposematic coloration and mimicry has a long and distinguished history, and has stimulated scientific inquiry in areas as diverse as chemistry, evolution, ecology, and behavior. Yet, many questions regarding signal function and ecological dynamics remain unknown. This dissertation attempts to address some of these questions about how a visual warning signal functions and how the environment changes its efficacy. First, I evaluated the role of luminance contrast in aposematic signaling using milkweed bugs as model prey and Chinese mantids as model predators. Predators learned to avoid unpalatable prey sooner and remembered to avoid unpalatable prey for longer when the prey had higher luminance contrast with the background. These results help define what makes a visual signal conspicuous and designate the importance of high luminance contrast in the efficacy of a warning color signal. Another important characteristic of warning coloration is the reason for the advertisement. I was able to identify and quantify the toxic compounds in both the host plant and the viceroy butterfly, a putative aposematic insect. These results provide a chemical mechanism for previous research that demonstrated that the viceroy was unpalatable to avian predators. Next, I was able to test the role of geographic variation in host plant and viceroy chemical defense and how that variation compared with the local abundance of a mimicry co-model of the viceroy, the queen butterfly. The results indicated the viceroy was more chemically defended and more unpalatable in locations where the queen was at low abundances. This result suggests that mimicry evolves in a geographic mosaic of co-evolution. Finally, I used molecular phylogenetic approaches to reconstruct and test the evolution of mimicry in the North American admiral butterflies (Limenitis: Nymphalidae). One species, L. arthemis, evolved the black, pipevine swallowtail mimetic form but later reverted to the white-banded ancestral form. This character reversion is strongly correlated with the geographic absence of the model species and its host plant, not the mimics host plant distribution. These results support the idea that loss of model in a geographic area is not an evolutionary stopping point for a Batesian mimic.
    • The Warring Forties: The Economic Consequences of World War II

      Fishback, Price V.; Jaworski, Taylor; Fishback, Price V.; Gowrisankaran, Gautam; Langer, Ashley; Xiao, Mo (The University of Arizona., 2014)
      This dissertation studies the impact of World War II on the development of the American economy after 1940. Scholars have long-debated the economic consequences of the war, particularly with reference to the macroeconomy and often relying on standard measures of aggregate economic performance. The approach in this dissertation is to study the microeconomic implications of mobilization for World War II. Specifically, the three main chapters address the following questions: What were the human capital costs of the manpower mobilization for young women? Did industrial mobilization promote the growth and diversification of manufacturing in the American South? How much did government spending on supply contracts contribute to migration and the change in the structure of wages between 1940 and 1950? The first chapter provides an overview of America's twentieth century wars and surveys the literature on the impact of World War II. In the second chapter, I find that greater exposure to manpower mobilization decreased young women's educational attainment initially, with important implications for family formation and labor market performance. From the analysis of the third chapter I conclude that the war led to modest reallocation of manufacturing activity toward high value- added sectors, but the war most likely did not create the modern industrial South. In the final chapter I provide evidence that migration induced by World War II played a role in reshaping the structure of wages during the 1940s. Together, the chapters provide important nuance and revisions to our understanding of World War II.
    • The wartime melodies of André Caplet.

      Allen, Marie-Christine Catherine.; Day, Larry; Mosher, Elizabeth; Fan, Paula (The University of Arizona., 1994)
      André Caplet (1878-1925) was a major figure on the musical scene for the first quarter of the twentieth century. He contributed substantially to the repertoire of the solo voice, and to that of choral and chamber music. He was moreover an acclaimed conductor; besides extensive engagements in Paris, Caplet was the conductor of French repertoire at the Boston Opera Company from 1910-14. His career was tragically cut short when he was forty-six years of age because of war-related injuries. An in-depth look at the compositions he left behind reveals a brilliant intellect, meticulous attention to detail, a tremendous ear for color, and keen sensitivity to poetic nuance. The richness of his poetic imagination and his technical resources resulted in a variety of oeuvres of originality and depth. He is unsurpassed as a text-painter in the history of mélodie. The name of André Caplet should be added to those of Debussy and Ravel as an important representative of musical impressionism. This paper examines the exquisite text setting of Caplet. I have chosen the wartime mélodies because of the depth and range of their emotional and musical content. Moreover, they are loosely linked by the undercurrents of war which, with their ever-changing, reflecting and refracting surfaces, run through these mélodies like an impressionistic stream. Caplet wrote predominantly for the mezzo-soprano voice during this period, perhaps using a richer voice to more richly express the depth of his experiences. These mélodies thus represent a wonderful addition to French repertoire for this Fach.
    • "A wasteland fortunes": History, destiny, and cultural frontiers in American literature

      Evers, Lawrence J.; Gwinner, Donovan R. (The University of Arizona., 2001)
      Throughout the nineteenth century, American authors produced literature that depicted the processes and effects of the conquest of North America, particularly the formation of the United States of America. Twentieth-century American writers have continued creating literature that portrays the history of the continent following the advent of Europeans in the "New World." This dissertation analyzes the conventions of historically oriented American literature. Interpretations of John Gast's painting Manifest Destiny and of selected works by James Fenimore Cooper, Timothy Flint, James Kirke Paulding, and William Gilmore Simms yield an exposition of the relevant narrative conventions. Subsequent readings of works by Nash Candelaria, Willa Cather, Cormac McCarthy, Simon Ortiz, Leslie Marmon Silko, and William T. Vollmann provide a basis for understanding how twentieth-century American authors adhere to and depart from conventionality. The central concern with literary conventions in this dissertation is the representation of historical agency. The nineteenth-century expansionist ideology "manifest destiny" serves as a conceptual context in which to discuss authors' attempts to depict the processes and effects of the conquest of North America. Specifically, this study examines the ways in which all of the authors under consideration attempt to show that the conquest of America was historically contingent and/or inevitable. A significant component of interpreting the portraits of history is a thorough consideration of how these writers represent American ethnicities and cross-cultural relations.
    • Water and nutrient management for wheat and barley grown under saline conditions.

      Khan, Mohammad Jamal.; Bohn, Hinrich L.; Glenn, Edward P.; Hendricks, David M.; Ffolliott, Peter F. (The University of Arizona., 1994)
      Two separate investigations, on wheat and barley were conducted under control environments. In the first experiment, two wheat varieties, selection line (SL) and Yecoro Rojo (YR) were grown in 100 mM NaCl salinized sand culture with the additional 2 levels (4 and 8 meq/L) of Ca, Mg and NH₄ application. Control treatments (0 salt plus 4 meq/L of Ca, Mg and NH₄) were also included. The fresh and dry matter yield after 4 weeks in salinized Hoagland solution and supplemental nutrient addition reveals that salinity significantly reduced the yield and the addition of 8 meq/L NH₄ increase the yield among the salt treatment pots followed by 8 meq/L supplemental Ca. Likewise, number of tillers and grain yield was also increased by the addition of 8 meq/L NH₄ to salinized Hoagland solution. SL produced significantly higher yields than YR. Water and osmotic potential were significantly increased with salinity but turgor potential was not effected significantly. Concentrations of Na and Cl were significantly higher in both varieties in the salt added plants, and the uptake was reduced by the high level of supplemental NH₄. Generally, YR (a salt sensitive variety) absorbed higher amount of Na, Mg, Cl and PO₄, which might be the possible cause of nutritional disturbance and hence reduced yield. In the second experiment, two selected barley varieties (California Mariout and Gustoe) were grown in lysimeter, irrigated with two NaCl salinity water (150 and 250 mM) and a control with two LF (0.2 and 0.4). As the salt concentrations of irrigation water increased, vegetative growth and grain yield reduced significantly. LF 0.4 had significant effect at moderate salinity on yield but was similar as LF, 0.2 when the salinity increased to 250 mM. Both varieties achieved the highest WUE for the above ground dry matter and grain yield at moderate salinity. Mariout was salt tolerant and high yielding both in and out of salinity. Soil salinity (ECₑ) and Na content increased as the salinity of irrigation water increased. Na concentration of leaf tissue was significantly increased, while Ca and K concentration decreased with increase in salinity. The possible reason for reduced yield at high salinity was the Ca deficiency.
    • Water and salt distribution in a soil under trickle irrigation

      Saraiva Leao, Moies Custodio,1939-; Fangmeier, Delmar D.; Dutt, Gordon R.; Matlock, W. G.; Stroehlein, Jack L. (The University of Arizona., 1975)
      A field study was conducted to determine water and salt distribution patterns in a soil irrigated by pairs of double-chamber, perforated polyethylene tubes. The study consisted of two experiments: a water distribution experiment and a salt distribution experiment. Both experiments were conducted at the same site with experimental plots having two perforated lines 9 m long, spaced 0.60 m. The tubing had outer orifices 0.5 mm in diameter spaced 0.30 m along the tubes. The water distribution experiment consisted of water application to the bare soil for periods of time of 3, 6, 9, and 12 hours. After each test a trench was dug normal to the irrigation tubes and samples were taken to determine soil moisture on a dry weight basis. Moisture profiles are presented for the various tests. The salt distribution experiment was conducted in the Fall of 1973 and repeated in the Spring of 1974. It consisted of four irrigation treatments comprising two irrigation levels and two levels of salt in the irrigation water (327 and 2000 milligrams per liter of salts). Experimental plots were planted with lettuce and soil samples taken after planting and after harvesting the lettuce. Soil samples were analyzed for electrical conductivity of the soil saturation extract, pH, calcium, magnesium, sodium, potassium and nitrates. Saturation extract conductivity profiles in the soil are presented for different treatments. After planting and after harvest concentrations of calcium, magnesium, sodium, potassium, nitrates and pH values are also shown. Seasonal water application and lettuce yields are presented for both trials Water movement in the soil was 2 to 3 times greater in the horizontal than in the vertical direction. Wetted soil volume showed a high positive correlation with both the volume of water applied and with time of application. Salt accumulation occurred mainly at the soil surface between the irrigation tubes and away from the main root zone of the plants. The surface accumulation was followed by a leached zone. There were no significant differences in yield among plots receiving different treatments. Seasonal water application was less than half of the seasonal amount of water normally applied for furrow irrigated lettuce in the Tucson area. It was higher than experimental determinations of seasonal consumptive use for lettuce at Mesa, Arizona. The study indicated that trickle irrigation with water of high salt content is likely to cause a high surface concentration of salts. Application of extra amounts of water by the trickle system, or another method, is recommended to leach the salts to a depth below the crop root zone.
    • Water and stress effects on growth and rubber : accumulation in guayule (Parthenium argentatum gray)

      Garrot, Donald Jerome.; Endrizzi, J. E.; Ray, D. T.; O'Leary, James W.; Matsuda, Kaoru; Fangmeier, Delmar D. (The University of Arizona., 1984)
      Recently, canopy temperature measurements and atmospheric vapor pressure deficits have been used to determine water stress in numerous plant species. A linear regression of the two parameters yields a crop water stress index (CWSI) baseline capable of determining a fraction of water stress between 0 (wet) and 100 (dry). Such a baseline was determined for one line of guayule (N396) in the spring of 1983 and used to determine time of irrigation for field plots. Three irrigation treatments were chosen based on CWSI measurements to aquire a relationship between rubber yield and water Stress. Treatments were irrigated when their respective CWSI measurements reached 0.30 (wet=1), 0.60 (medium=2), and 0.90 (dry=3). Duplicate tests were planted to determine if water delivery by drip irrigation differed from furrow irrigated plots. Very good correlations exist between rubber yield and seasonally averaged CWSI (r = 0.85). The interrelationship of rubber yield and total water applied was also high with r = 0.87. The highest rubber yield occurred in March in treatment 1 (wet) in the furrow irrigated field. Rubber yield was positively correlated with total water applied and inversely correlated with CWSI. Small differences were observed between the type of water delivery system used with similar treatments from both fields not being significantly different. The wet and medium treatments in both fields were about the same with the dry treatment being significantly different from the wet and medium treatments for total water applied. This indicates that guayule is not as sensitive to changes of 0.30 CWSI units as other species measured. Correlations between the CWSI and soil moisture deficits were very good with r=0.83 for 1983 and r=0.91 for 1984 indicating the CWSI can be used accurately to determine soil moisture deficits and vice-versa. A 0-stress moisture deficit range (0-SMDR) was determined for guayule where 0.0-2.26 and 0.0-4.58 cm (1983 and 1984, respectively) of water could be depleted from the soil profile before the plants showed stress as indicated by the CWSI. The 0-SMDR appears to be constant for a particular plant species in the same field for a particular year and may further define and standardize plant available soil moisture.
    • Water at the Phoenix landing site

      Wyant, James C.; Drake, Michael J.; Smith, Peter Hollingsworth; Wyant, James C.; Drake, Michael J.; Boynton, William; McEwen, Alfred; Hartmann, William K. (The University of Arizona., 2009)
      The Phoenix mission investigated patterned ground and climate in the northern arctic region of Mars for 5 months starting May 25, 2008. A shallow ice table was uncovered by the robotic arm in a nearby polygon's edge and center at depths of 5-15 cm. In late summer snowfall and frost blanket the surface at night; water ice and vapor constantly interact with the soil. Analysis reveals an alkaline Ph with CaCO3, aqueous minerals, and salts making up several wt% of the soil; liquid water is implicated as having been important in creating these components. In combination with the oxidant perchlorate (~1 wt%), an energy source for terrestrial microbes, and a prior epoch of higher temperatures and humidity, this region may have been a habitable zone.
    • Water Conservation in Biofuels Development: Greenhouse and Field Crop Production with Biochar

      Waller, Pete; Villarreal Manzo, Luis Alberto; Waller, Pete; Waller, Pete; Slack, Donald C.; Yitayew, Muluneh; Hawkins, Richard (The University of Arizona., 2009)
      Biochar incorporation in soils has the potential to remove carbon from the atmosphere and to improve soil quality. This research focused on evaluation of the benefit of biochar incorporation in an Arizona soil. Different concentrations of biochar (charcoal from mesquite biomass-derived black carbon) were added to soil in greenhouse experiments. Seven common or potential Southern Arizona crops (alfalfa, wheat, cotton, grain and sweet sorghum, barley and switch grass) were evaluated in the greenhouse experiment. In this experiment; increased biochar concentration treatments produced greater height and biomass production in alfalfa. Sorghum biomass production also increased with biochar concentration. There were no significant differences in biomass production in wheat and barley with increased biochar concentration. Switch grass biomass production had a significant negative correlation with increased biochar concentration. Sweet sorghum biomass production was evaluated in a field experiment conducted at the University of Arizona Red Rock Agricultural Center. A relatively small amount of biochar was incorporated in the top 20 cm of soil in one treatment and soil only was the other treatment: there were no significant differences in yield.Water characteristic curves and bulk densities were measured for biochar/soil mixes. The FASE model was used to simulate evapotranspiration and crop yield for the field sorghum experiment and for several crops grown in the Valsequillo Irrigation District, Puebla, Mexico with measured soil parameters. The model predicted no significant increase in sorghum yield for the level of biochar incorporated in the soil. An increase in yield was predicted for Valsequillo crops.