Now showing items 12553-12572 of 20421

    • Multimode Interference in Optical Fibers and Its Applications in Fiber Lasers and Amplifiers

      Peyghambarian, Nasser; Zhu, Xiushan; Peyghambarian, Nasser; Schulzgen, Axel; Kueppers, Franko (The University of Arizona., 2008)
      Multimode interference (MMI) in optical fibers has been studied and its applications in optical fiber lasers and amplifiers have been proposed and demonstrated in this thesis. When a single-mode fiber is spliced onto a multimode fiber, quasi-reproduction of the field from the single-mode fiber, also called “self-imaging”, occurs periodically along the multimode fiber where the phase differences between the strongly excited modes are very small. The properties of self-imaging in multimode optical fibers have been investigated experimentally and theoretically in this thesis. Key parameters for the design of MMI-based fiber devices have been defined and their corresponding values have been provides for the 50 μm and 105 μm multimode fibers. By use of the self-imaging effect, a fiber laser with single-transverse-mode output while using a multimode rare-earth-doped fiber has been demonstrated as an alternative route to overcome the constraints of an active single-mode fiber. The first MMI-based fiber laser in the world has provided a perfect beam quality (M² = 1.01) and an inherent narrow spectrum (Δλ(3dB) < 0.5 nm). Linearly-polarized narrow-linewidth single-transverse-mode emission has also been obtained from a MMI fiber laser utilizing a single-mode fiber inscribed with a polarization-maintaining fiber Bragg grating. Moreover, high power MMI fiber lasers and amplifiers utilizing rare-earth doped silica large-core multimode fibers have been proposed and their critical features, such as efficiency, optical spectrum, and beam quality, have been investigated. On the other hand, because exclusively excited LP₀, n modes inside the multimode fiber segment are represented by apertured Bessel fields that have long propagation invariant distances, nondiffracting beams can be generated from the MMI-based fiber devices. In this thesis, the principle of generating nondiffracting beams from multimode optical fibers has been described and the propagation characteristics of the generated beams have been investigated. Active MMI fiber devices to generate tens of watts or even hundreds of watts nondiffracting beams have also been proposed.
    • MULTIOBJECTIVE DESIGN OF DEVELOPMENT PROGRAMS WITH APPLICATION TO THE SAN TIBURCIO REGION, ZACATECAS, MEXICO

      Bulfin, Robert; Armijo Tamez, Jesus Roberto (The University of Arizona., 1981)
      The formulation of land-use programs fostering the social development of a community is the basic aim of the present work. The San Tiburcio region, located in northern Mexico, provides the background for the design of specific programs as well as a vehicle to present and illustrate the proposed procedure. The advocated program design procedure is made up of four distinct stages; value structuring, project screening, program delineation, and program selection. At each stage a specific technique is proposed in order to achieve the particular output sought. The value structuring phase strives to achieve a characterization of the objective structure, as advocated by a group, and the identification of objective measures useful in the decision making stage. Q-analysis is used to study the structure of the objectives as implied by a given relation among these objectives. The objective structure for the San Tiburcio region is assessed and studied in the context of the proposed value structuring activities. Based upon previous research, a set of land-use projects is formulated by a multidisciplinary team and submitted as potential candidates to integrate a program for the San Tiburcio region. Related to this set of land-use projects is another set of infrastructural and industrial projects proposed by various governmental agencies. A mixed-integer linear multiobjective programming (MILMOP) model is used to handle the determination of specific program profiles. Due to computational and data limitations, a prior screening of alternatives is undertaken, using a knapsack-type model. By considering several types of objectives and levels of resources, a classification of projects is achieved. Two plausible screening criteria are developed to deal with the San Tiburcio problem. The set of screened projects is used as the starting basis of the program delineation stage. A series of program profiles is generated by obtaining various half-compromise solutions of the MILMOP model. Each half-compromise solution is obtained when a particular set of weights is used for the various objective functions. The selection of a given program is undertaken within the context of a multiattribute decision problem. To this end, a technique based on polyhedral dynamics is developed and used to produce a ranking of programs. A series of sensitivity runs are conducted to conclude that only two programs of the five considered are ranked consistently higher than the rest.
    • A multiobjective global optimization algorithm with application to calibration of hydrologic models

      Sorooshian, Soroosh; Yapo, Patrice Ogou, 1967- (The University of Arizona., 1996)
      This dissertation presents a new multiple objective optimization algorithm that is capable of solving for the entire Pareto set in one single optimization run. The multi-objective complex evolution (MOCOM-UA) procedure is based on the following three concepts: (1) population, (2) rank-based selection, and (3) competitive evolution. In the MOCOM-UA algorithm, a population of candidate solutions is evolved in the feasible space to search for the Pareto set. Ranking of the population is accomplished through Pareto Ranking, where all points are successively placed on different Pareto fronts. Competitive evolution consists of selecting subsets of points (including all worst points in the population) based on their ranks and moving the worst points toward the Pareto set using the newly developed multi-objective simplex (MOSIM) procedure. Test analysis on the MOCOM-UA algorithm is accomplished on mathematical problems of increasing complexity and based on a bi-criterion measure of performance. The two performance criteria used are (1) efficiency, as measured by the ability of the algorithm to converge quickly and (2) effectiveness, as measured by the ability of the algorithm to locate the Pareto set. Comparison of the MOCOM-UA algorithm against three multi-objective genetic algorithms (MOGAs) favors the former. In a realistic application, the MOCOM-UA algorithm is used to calibrate the Soil Moisture Accounting model of the National Weather Service River Forecasting Systems (NWSRFS-SMA). Multi-objective calibration of this model is accomplished using two bi-criterion objective functions, namely the Daily Root Mean Square-Heteroscedastic Maximum Likelihood Estimator (DRMS, HMLE) and rising limb-falling limb (RISE, FALL) objective functions. These two multi-objective calibrations provide some interesting insights into the influence of different objectives in the location of final parameter values as well as limitations in the structure of the NWSRFS-SMA model.
    • Multipath Data Transport in Named Data Networking

      Zhang, Beichuan; Schneider, Klaus; Gniady, Chris; Hartman, John; Efrat, Alon (The University of Arizona., 2019)
      The idea of multipath transport is almost as old as the Internet itself. By using multiple paths, one can build a reliable system out of many unreliable components. Moreover, by distributing the load among multiple paths, one can significantly improve the performance of this system. In this dissertation, we investigate the use of multipath data transport in Named Data Networking (NDN), a novel Internet architecture. NDN’s core features (stateful forwarding, pervasive caching, multi-destination routing) make it inherently more capable of exploiting multiple paths than the current TCP/IP Internet. For example, in NDN, the same data can be served by multiple repositories and caches, resulting in many paths being used. Specifically, this dissertation works out the details to improve NDN’s performance in three different aspects: First, we design a congestion control scheme that improves performance when data is retrieved over multiple paths and from multiple repositories. Second, we design a multipath routing protocol that maximizes the path choice at the NDN forwarding plane, while minimizing path length and avoiding loops. Third, we design a novel traffic engineering scheme that distributes traffic hop-by-hop, rather than tunneling traffic between multiple endpoints at the network edge.
    • MULTIPHASE AVERAGING OF PERIODIC SOLITON EQUATIONS

      Forest, M. Gregory (The University of Arizona., 1979)
    • Multiple Approaches to the Restoration of Disturbed Desert Land

      Pepper, Ian L.; Banerjee, Monisha J.; Pepper, Ian L.; Reynolds, Kelly; Glenn, Ed P. (The University of Arizona., 2009)
      Three experiments were conducted to examine restoration of disturbed land in Arizona. The first experiment attempted to revegetate abandoned farmland by direct seeding native seeds and using various soil preparation techniques, amendments, and weeding of Salsola iberica. Only irrigation and weeding had a significant effect on seed germination and canopy cover. Irrigation increased plant cover on plots, but weeds dominated the cover. A seedbank study conducted near the end of the second growing season found the soil was dominated by weeds and contained few viable native seeds. The results illustrate the difficulty of establishing native plants on abandoned desert farmland due to the dominance of weedy species, the presence of salts in the soil, and the lack of adequate soil moisture.The second experiment, a lysimeter study, tested the efficacy of different evapotranspiration (ET) soil cover designs for stabilization of acidic copper mine tailing piles. The study evaluated the effectiveness of capillary barriers (CB) to contain the waste found in tailings and different plants to revegetate the piles. The ET covers reduced infiltration of water into tailings. Copper concentrations increased significantly in plant tissue grown on the ET covers compared to plants grown in the greenhouse. Plants did not exhibit signs of phytotoxicity and concentrations were below levels toxic to all domestic animals except sheep. The CB did not reduce water infiltration into the tailings or upward migration of copper into the soil cover. Vegetation is vital to an effective ET cover. A mix of transplanted shrubs and seeded grasses and forbs establish long-term, sustainable vegetation.The third experiment examined the influence of biosolids on the bacterial communities within mine tailings by bacterial counts and bacterial diversity. The diversity of neutral copper mine tailings two weeks after biosolid application was compared with that of desert soil via cloning and sequencing of PCR amplified community 16S rRNA. Culturable heterotrophic plate counts (HPC) increased following biosolid addition. Total direct counts exceeded HPC by approximately two orders of magnitude. Overall, biosolid-amended tailings contained large numbers of bacteria diverse in nature and with many of the traits of normal desert soil bacterial communities.
    • Multiple beam correlation using single-mode fiber optics with application to interferometric imaging.

      Burke, James J.; Shaklan, Stuart Bruce.; Shack, Roland V.; Hege, E. Keith (The University of Arizona., 1989)
      A study of the application of single-mode fiber optics to the multiple-beam interferometric recombination problem is presented. In the laboratory, the fibers have been used in wide bandwidth, two-arm, Mach-Zehnder test interferometers as well as a 5-telescope imaging interferometer connected to an all-fiber beam combiner. Based upon these experiments and some theoretical studies it is shown that fiber optics and fiber optic components such as directional couplers provide an excellent alternative to conventional optics such as mirrors, beamsplitters, and relay lenses. The equations describing the measurement of the complex degree of coherence in an interferometer with a single-mode fiber in each arm are derived. The equations reveal an important feature of the fibers: they filter phase fluctuations due to aberrations and turbulence at the input and convert them to intensity fluctuations at the output. This leads to a simplification of the calibration of measured visibilities. The coupling efficiency of light which has passed through a turbulent atmosphere is also studied as a function of fiber parameters and turbulence conditions for both image motion stabilized and non-stabilized cases. For the former case, coupling efficiency remains greater than 50% as long as telescope diameter is no larger than the turbulence coherence length. Beam combination architectures using arrays of directional couplers are fully discussed. Arrays accommodating up to 20 input beams are presented. The arrays require only N detector pixels for N input beams. A scheme of temporal multiplexing of the phase of each beam is used to identify individual fringe pairs. One possible scheme allows wide bandwidths even for large numbers of beams. A 5-telescope interferometer has been constructed and connected to an all-fiber beam combiner. Two extended objects were observed and reconstructed using standard radio astronomy VLBI software. The interferometer and beam combiner had good thermal and polarization stability and high throughput. Reconstructed images had dynamic ranges of about 50.
    • Multiple Case Study of (Re)Design and Restructuring of Studio Arts Schools and Departments in the Research University Environment

      Rhoades, Gary; Lund, Kimberley Ann; Rhoades, Gary; Maldonado-Maldonado, Guadalupe; Sevigny, Maurice (The University of Arizona., 2006)
      "Multiple Case Study of (Re)-Design and Restructuring of Studio Arts Schools and Departments in the Research University Environment" investigates the effect of a changing academic value system, as it is manifest through activities of studio arts program redesign and restructuring within the specific context of large, public research universities in the United States of America. A multiple case study (of three distinct American studio arts units) of the academic restructuring phenomenon within this specific locus, examining the interplay of studio arts culture with the larger institutional mandates in the restructuring process, this work approaches restructuring as a series of cultural and survivalist responses to a complex and changing environment.
    • Multiple criteria analysis of economic, environmental and water use problems in an irrigation district of Mexico

      Yakowitz, Diana; Larson, Dennis; Salazar Moreno, Raquel (The University of Arizona., 2000)
      The Alto Rio Lerma Irrigation District (ARLID), located in the state of Guanajuato in Mexico, is an agricultural area whose sustainability depends partially upon groundwater withdrawal for crop irrigation. Because of high pumping demands and current land-management practices, water levels in the regional groundwater aquifers have declined severely, resulting in aquifer overdraft. The potential adverse consequences of this overdraft cannot be overstated, as the long-term economic viability and environmental integrity of the region is threatened. In order to analyze this economic, environmental, and water use problems in this region, simulation of the agricultural system was performed and associated water use impacts quantified under different management scenarios. Linear programming identified the 12 optimal cropping patterns, and then multi-criteria decision-making methodologies were applied to rank and identify the best cropping pattern (satisficing solution). The GLEAMS model was used to simulate the amounts of water, nitrate, and pesticides in both runoff and percolation for each cropping pattern. In order to quantify the economic and environmental impacts of aquifer overdraft, two attributes were used; pumping costs and an aquifer exploitation coefficient. Three multiple criteria methods: Q-analysis, ELECTRE II, and the Range of Value Method, were evaluated and the latter method was selected to analyze the payoff matrix for the ARLID, where 12 alternatives, each with 13 attributes, were considered. The results show the best alternative for effectively balancing environmental with economic considerations was the farming practice, consisting of land leveling, growing vegetables such as red tomato, and controlled groundwater withdrawals to preserve aquifer sustainability. Low water availability does not necessarily reduce farmer's profits, if new water saving alternatives are applied, combined with more profitable crops. Given that ROV method only considers full compensation between objectives, this research contemplate an extension for the nonlinear case in order to assess the whole range of values of the objective function. The final findings suggest that the best methodology was to apply L1 in the lower levels and then L2 for the highest level in the hierarchy. In this manner, the partial compensation between objectives is considered and also the decrease in the uncertainty of alternatives selection.
    • MULTIPLE DETERMINANTS OF STATE AND LOCAL GOVERNMENT FISCAL EFFORT IN THE UNITED STATES

      Graham, William Rex, 1935- (The University of Arizona., 1969)
    • MULTIPLE INPUT-OUTPUT FEEDBACK SYNTHESIS INCORPORATING CROSS-COUPLING

      Ferg, David Alvin, 1943- (The University of Arizona., 1971)
    • Multiple maps and multiple reference frames in the hippocampal representation of space

      McNaughton, Bruce L.; Gothard, Katalin Margit, 1960- (The University of Arizona., 1996)
      Populations of simultaneously recorded hippocampal place cells were studied in three tasks that required shuttling between a variably placed box and a reward location predicted by fixed or variably located landmarks. Groups of place cells fired at fixed locations relative to the behaviorally relevant landmarks or to the absolute spatial framework of the environment. The initial segment of the journeys was represented by a sequence of cells that fired at fixed distances with respect to the landmark of origin, behind the animal, irrespective of where that landmark was located. The final segments of the journeys were represented by cells that fired at fixed locations relative to the landmark of destination. We propose that on the initial parts of the journey, the spatial coordinate represented by each cell was updated predominantly by path integration. When approaching the landmark of destination, the coordinates were updated and corrected by visual landmarks (or other sensory cues). The intermediate zone was characterized by a transition from the reference frame of the origin to the reference frame of the destination. Small distortion of the environment led to a smooth, continuous transition, while a large distortion led to abrupt transitions. These observations suggest that in the hippocampus, place can be represented in multiple spatial reference frames established by behaviorally relevant landmarks. Further experiments showed that these landmarks, or their sensory properties, are not represented explicitly by place cells, because cells did not maintain their landmark-related firing in a similar task, performed in a different environment.
    • MULTIPLE NOMINATIVE AND ADVERSITY CONSTRUCTIONS IN JAPANESE.

      Oehrle, Richard; NISHIO, HIROKO. (The University of Arizona., 1982)
      In Japanese linguistics, multiple nominative sentences, passives and causatives have been widely discussed both in the fields of traditional grammar and generative grammar. Some arguments, mainly in generative grammar, are overviewed; and some counterarguments are presented. Furthermore, these constructions, which have been treated separately from each other in the grammar, are discussed together. Some interactions of these constructions, which have various types, are shown, with focus on one particular type in each construction. This particular type involves a relationship of two NPs, namely, an NPx -no NP relationship (NP's NP). In addition, with the utilization of bound morphemes such as sase (the causative morpheme), the lexical approach, which is a recent trend in generative grammar, is taken and defended.
    • MULTIPLE OBJECT SPECTROSCOPY: THE MX SPECTROMETER DESIGN.

      HILL, JOHN MILTON. (The University of Arizona., 1984)
      This dissertation describes the techniques involved in using a fiber optic coupled spectrometer to do multiple object spectroscopy of astronomical objects. The Medusa spectrograph, with optical fibers fixed in a focal plane aperture plate, was used to study clusters of galaxies via velocity distributions. Some relevant problems in the study of the structure and dynamics of clusters of galaxies are outlined as motivation for building a multiple fiber spectrometer. The history of fiber optic spectroscopy in astronomy is presented along with an outlook for the future. The results and experience gained from the Medusa spectrograph are used to design a second generation instrument. The MX Spectrometer uses optical fibers which are positioned remotely under computer control. These fibers are optically matched to the telescope and spectrograph optics to achieve optimum performance. The transmission, flexibility, and image scrambling properties of step-index silica fibers allow efficient reformatting of multiple objects into the spectrometer entrance aperature. By allowing spectra of 32 objects to be obtained simultaneously, the MX Spectrometer will make an order of magnitude increase in the quantity of spectroscopic data that can be recorded with a large telescope. Mechanical, control, and optical elements of the MX design are discussed. Telescope and fiber parameters influencing the design of the fishermen-around-the-pond mobile fiber head are detailed. Results of testing the stepper motor driven fiber positioner probes are described. The algorithm for controlling the motion of 32 positioners in the telescope focal plane without collisions is outlined. Detector performance and spectrometer efficiency are considered for both the Medusa and MX systems. The use of a Charge Coupled Device (CCD) array detector provides increased quantum efficiency, dynamic range, and stability, as well as allowing digital sky subtraction. Microlenses and their use in correctly coupling optical fibers to the telescope and spectrograph are discussed. In particular, the pupil-imaging technique for microlens matching to fibers is introduced.
    • A multiple objective decision model for the evaluation of advanced manufacturing system technologies.

      Askin, Ronald G.; Demmel, Johann George; Sanchez, Paul J.; Thompson, William J. (The University of Arizona., 1991)
      Ordinary financial measures oversimplify the evaluation of Advanced Manufacturing System Technologies (AMST). A multiple objective decision model is developed which avoids the shortcomings of the traditional evaluation methods. The model is comprised of three objectives: Pecuniary, Strategic, and Tactical. The Pecuniary objective is based upon traditional Discounted Cash Flow techniques, with the results normalized to a [-1, +1] (worst-best) scale. The Strategic and Tactical objectives are based upon the concept of qualitative flows, and a qualitative discounting method is employed to discount the qualitative costs/benefits to a present value. The three objectives are traded-off using the Composite Programming technique, resulting in a rank ordering of the alternatives which are under consideration. The three objectives of the model are broken down into attributes which define the objective, and these attributes are "mapped" into the organization of a manufacturing environment. It is shown that the model covers the entire manufacturing environment. It is shown that the model covers the entire manufacturing organization in accounting for the costs/benefits of the proposed AMST alternatives. The influence of the three objectives on the final score is analyzed using a mixture experiment. The mixture experiment provides insight into the effect of varying the importance of each objective and its effect on the final rankings. This provides the analyst a method to determine which attributes and/or objectives are critical for the AMST alternative being investigated. Realizing that the evaluation of AMST hinges on events which are to occur in the future, and these events are not known for certain, the procedure is extended to include a measure of risk. Cash flows, qualitative flows, interest rates, and project lengths are provided by the decision maker as pessimistic, most likely, and optimistic estimates. An analysis is provided where the inputs are assumed to be independent. The model is then further enhanced to allow time dependence between cash flows and qualitative flows of a single attribute. Results are provided as a mean and variance of the evaluation score, objective scores, and indices, along with frequency distributions. A case study analysis is provided which shows the application of the techniques developed in this work.
    • Multiple oral re-reading for subjects with alexia

      Beeson, Pelagio M.; Insalaco, Deborah Michelle (The University of Arizona., 1999)
      This series of case studies explored the relationship between reading profiles and the benefits of text reading treatment. This research was motivated by the finding that some subjects with deep alexia read aloud words presented in a text context more accurately than words presented in isolation (Silverberg, Vigliocco, Insalaco, & Garrett, 1998). The benefit, which was specific to closed class elements, was consistent with a model of sentence production that hypothesizes that open and closed class elements are retrieved differently (Garrett, 1984, 1990). The treatment method used, Multiple Oral Re-reading (MOR) (Moyer, 1979), was known to improve reading rate for subjects with word length effects (Beeson, 1998; Tuomainen & Laine, 1991) and may have been an influence in changing reading processes for subjects with word length and grammatical class effects (Beeson & Insalaco, 1999). Further, oral reading treatment employing text as stimuli was demonstrated to improve other language processes including auditory comprehension and spoken language (Cherney, 1995; Cherney, Merbitz, & Grip, 1986). Thus, the goals of this study were to determine who benefited particularly from text treatment and whether text treatment influenced other reading and language processes. Six subjects with acquired alexia associated with stroke participated in an AB case study design that included a baseline observation period between initial assessment and treatment. After the baseline period, they received 10 weeks of MOR treatment. Treatment was followed by assessment. Of the six subjects, three had grammatical class effects during single word reading (MW, ED, MEL). One of them (MW) improved oral reading rate and accuracy for single words and text at post-treatment testing. The fourth subject (MB), who read text more accurately and more quickly than single words, but did not have a grammatical class effect, did not change oral reading rate or accuracy, but during treatment increased the complexity of his pleasure reading. A fifth subject (SM) increased accuracy of oral reading of closed class elements at post-treatment assessment and was able to use that skill as a scaffold for improved spoken language. The sixth subject (LW) was already a highly accurate reader and showed no change, but continued to practice oral reading as an exercise.
    • MULTIPLE PEPTIDE RECEPTORS AND SITES OF ACTION IN THE CANINE SMALL INTESTINE (OPIOIDS, MOTILIN, TACHYKININS, INTESTINAL MOTILITY, SUBSTANCE P).

      Burks; HIRNING, LANE DURAND. (The University of Arizona., 1986)
      Motility of the small intestine is a result of complex neurochemical and hormonal interactions within the intestine. The net motility (contraction) of the intestine is a balance of the influences from the central nervous system, enteric nervous system and hormonal changes in the body. Recently, the discovery of several peptide neurotransmitters common to the brain and the intestine has stimulated new research into the influence of these novel neurotransmitter candidates on intestinal motility at the level of the enteric (intestinal) nervous system. The present studies examined the contractile actions of three families of peptides, the opioids, tachykinins and motilin. Each of these peptide groups has been localized in the intestine, and suggested to function in the control of intestinal motility. The peptides were administered by intraarterial injection to isolated segments of canine small intestine and the resulting contractile activity measured. The results of these experiments demonstrate that all of these peptides may elicit contractile activity of the intestine in very low doses. These actions were further examined, using pharmacological antagonists, to determine the mechanism of action and the receptor types involved in the contractile actions. The opioid peptide induced responses were found to be mediated by two receptor types, mu and delta, located on the enteric nerve and smooth muscle, respectively. Similarly, the tachykinin induced contractions were also found to be due to actions on two receptor types, SP-P and SP-K, located on the nerve and muscle layers, respectively. These data suggest that the opioids and tachykinins may have multiple functions in the intestine dependent on the site of action and the receptor type involved in the response. Administration of motilin induced long-lasting contractile patterns in the intestine. The results also suggest that the actions of motilin are mediated by intermediate neurons of the enteric plexes which synapse on terminal cholinergic motor neurons.
    • Multiple Roles for the Transcription Factors Sox6 and Jumonji in Mouse Hematopoiesis

      Brilliant, Murray H.; Erickson, Drew Talyn; Brilliant, Murray H.; Schroeder, Joyce; Weinert, Ted (The University of Arizona., 2006)
      Sox6, a member of the Sox transcription factor family, is essential for the silencing of epsilon-y-globin gene expression in definitive erythropoiesis of mice and humans. Homozygous Sox6 null mice are neonatal lethal, precluding analysis at later stages. We created adult mice that are deficient in Sox6 specifically in hematopoietic tissues, by transplanting embryonic liver stem cells from Sox6-deficient mice into lethally-irradiated congenic wild-type adult mice. The mice receiving mutant stem cells (mutant-engrafted) showed high expression levels of epsilon-y in bone marrow, spleen and circulating blood compared to mice receiving wild-type and heterozygous stem cells (control-engrafted). The level of expression of epsilon-y in circulating blood was directly correlated with the percentage of successful mutant donor cell engraftment. Additionally, the mutant-engrafted adult mice showed an increase in erythroid precursor cells in bone marrow, spleen and blood. Thus, Sox6 continues to function as a major regulator of epsilon-y in adult definitive erythropoiesis and is required for normal erythrocyte maturation. Moreover, Sox6 may provide a novel therapeutic target by reactivating epsilon-y in patients with hemoglobinopathies such as sickle cell anemia and beta-thalassemia.We have also identified another transcription factor, jumonji, as a downstream target of Sox6. Jumonji is a crtitical transcription factor in neural, cardiac and erythroid development. We report here that jumonji is over-expressed in the fetal liver of Sox6-deficient mice (p100H/p100H). Transfection assays in H2.35 cells reveal that a ~1.6-kb genomic fragment, including the 5' UTR of jumonji, contains both promoter activity and Sox6-mediated repression. Chromatin immunoprecipitation and electromobility shift assays demonstrate that Sox6 binds to a region within the second exon of jumonji. Further transfection analyses confirm that one of five putative binding sites for Sox6 in this region is required for the majority of Sox6-mediated transcriptional repression. In irradiated mice engrafted with Sox6-deficient hematopoietic stem cells, jumonji expression levels are significantly elevated in blood and bone marrow. These results demonstrate that Sox6 plays a major role in the direct repression of jumonji transcription, and it is likely that jumonji plays a cell-autonomous role in the subsequent hematopoietic cell phenotype seen in Sox6-deficient mice.
    • MULTIPLE SPACE SUBDIVISIONS

      Marley, Gerald C., 1938- (The University of Arizona., 1967)
    • Multiple stories: Developing literacy in an ESL/ESP aviation program

      Butterfield, Carol Long.; Goodman, Kenneth; Goodman, Yetta; Short, Kathy G.; McCarty, Teresa (The University of Arizona., 1994)
      A basic goal of an English for Specific Purposes (ESP) program is to enable the language learner to function within an academic discipline, science and technology occupation, or a vocational occupation by using English. This teacher researcher case study explores the English literacy development of three adult Japanese student pilots within a holistic English for Specific Purposes (ESP) program. The setting of this five month naturalistic case study was on a small airport in the Southwestern United States. Experiential literacy events were provided to encourage student pilots to develop English literacy while learning aviation concepts. A preliminary case study with one student was conducted to evaluate and modify data collection methods, and ESP curriculum and organization. Data collection included participant observation and field notes, dialogue journals between students and the teacher researcher, oral and written interviews, checklists, and audio-taping methods. Three themes emerged through the constant comparative method of data analysis: (1) self perception, (2) developing relationships, and (3) developing literacy strategies. These three themes reflect the process of how and through what particular issues students developed English literacy. Findings from the analysis of data suggest that English literacy develops differently, and has distinct meanings for each person. In contrast to traditional ESP and ESL programs that emphasizes the transmission of language, a holistic ESP program provides opportunities for adult student pilots to develop English literacy through a process of inventing and appropriating English for his/her own purposes and needs. Findings also indicate that learning the form and function of language is not enough. Other language processes and social interactions enhance learning and support language development. Current research within the English for Specific Purposes field focuses on the description of the language as product of a particular academic/scientific/occupational situation that a student needs to learn to be successful. This dissertation seeks to refocus the direction in ESP research and contribute to the understandings of the process of literacy development in a holistic ESP program.