Now showing items 2066-2085 of 20306

    • Calibration and Interpretation of Holocene Paleoecological Records of Diversity from Lake Tanganyika, East Africa

      Alin, Simone Rebecca; Cohen, Andrew; Flessa, Karl; Overpeck, Jonathan; Reinthal, Peter; Robichaux, Robert (The University of Arizona., 2001)
      Lake Tanganyika is a complex, tropical ecosystem in East Africa, harboring an estimated 2,100 species. Extensive watershed deforestation threatens the biodiversity and ecological integrity of the lake. In this dissertation, ecological and paleoecological methods were employed to study the distribution of invertebrate biodiversity through space and time, with particular emphasis on linkages between biodiversity and land –use patterns. Ecological surveys of fish, mollusc, and ostracod crustacean diversity at sites in northern Lake Tanganyika representing different levels of watershed disturbance revealed a negative correlation between biodiversity and intensity of watershed disturbance. To elucidate the long -term relationship between disturbance and biodiversity, paleoecological records of invertebrates offshore from watersheds experiencing different degrees of anthropogenic disturbance were examined. Life, death, and fossil assemblages of ostracod valves were compared to assess the reliability and natural variability inherent to the paleoecological record. These comparisons indicated that paleoecological (i.e. death and fossil) assemblages reliably preserve information on species richness, abundance, and occurrence frequency at comparable -to- annual resolution. Unlike life assemblages, species composition of paleoecological assemblages reflects input of species from multiple habitat types. Ostracod paleoecological assemblages are characterized by spatiotemporal averaging that renders them representative of larger areas and longer time spans than life assemblages. Thus, paleoecological assemblages provide an efficient means of characterizing longer -term, site -average conditions. Natural variability in ostracod fossil assemblages from a sediment core representing the Late Glacial to the present indicates that abundance of individual ostracod species is highly variable. Ostracod assemblages were preserved in only the most recent 2,500 years of sediment. Species composition of ostracod assemblages reflects lake water depth. Core geochemical data indicate that the coring site may have been below the oxycline for ~2,000 years, inhibiting ostracod survival and preservation. Paleoecological, sedimentological, and stable isotope data revealed differences in biodiversity and watershed disturbance through time offshore from a pair of sites. The protected site is offshore from Gombe Stream National Park (Tanzania), the other offshore from a deforested watershed outside the park. Offshore from the deforested watershed, sedimentation rates increased, and turnover in ostracod species composition occurred during the past 50 years. Comparable changes were not observed offshore from the park.
    • Calibration and testing of the 6.5 m MMT adaptive optics system

      Angel, Roger P.; Johnson, Robert L. (The University of Arizona., 2001)
      This dissertation describes the development, calibration, and testing of the adaptive optics system for the 6.5 m Multiple Mirror Telescope. By employing a deformable secondary mirror, the MMT adaptive optics system uniquely solves several problems typical of astronomical adaptive optics systems. Extra components are eliminated, improving throughput and reducing emissivity. Since the adaptive secondary is integral to the telescope, a corrected beam is presented to any instrument mounted at Cassegrain focus. The testing of an adaptive mirror, which is large and convex, poses a new and difficult problem. I present a test apparatus that allows complete calibration and operation, in closed-loop, of the entire adaptive optics system in the laboratory. The test apparatus replicates the optical path of the telescope with a wavefront error of less than 500 nm RMS. To simulate atmospheric turbulence, machined acrylic plates are included. A phase-shifting interferometer allows calibration of the Shack-Hartmann wavefront sensor and reconstruction algorithms; comparisons agree to one-third of the root-mean-square wavefront. First, techniques were developed to align the apparatus and measure residual aberration. Then, the wavefront sensor was calibrated by measuring its response to introduced tilt. Lastly, a Fourier wave-optics approach was used to produce a modal wavefront reconstructor. The adaptive secondary mirror uses electro-magnetic force actuators. Capacitive position sensors are placed at each actuator to permit control of the mirror shape without measuring the reflected wavefront. These sensors have nanometer resolution, but require calibration. To calibrate the sensors, I developed a small optical instrument which measures the thickness of transparent films to an absolute accuracy of 5 nm with a precision of 2 nm. The device has applications far beyond the scope of this research. Twenty-four of these optical gap sensors have been built to calibrate the 336 capacitive sensors on the adaptive secondary mirror. Mirror displacements measured using gap sensors and a phase-shifting interferometer agree to 2 percent of the displacement. The gap sensors allow for quick and accurate calibration of the capacitive sensors without the difficulty of installing an interferometer on the telescope.
    • Calibration and validation of aquifer model.

      Sagar, Budhi,1943-; Kisiel, Chester C.; Duckstein, Lucien; Sanders, J. L.; Evans, Daniel D.; Simpson, Eugene S. (The University of Arizona., 1973)
      The main aim of this study is to develop a suitable method for the calibration and validation of mathematical models of large and complex aquifer systems. Since the calibration procedure depends on the nature of the model to be calibrated and since many kinds of models are used for groundwater, the question of model choice is broached first. Various aquifer models are critically reviewed and a table to compare them as to their capabilities and limitations is set up. The need for a general calibration method for models in which the flow is represented by partial differential equations is identified from this table. The calibration problem is formulated in the general mathematical framework as the inverse problem. Five types of inverse problems that exist in modeling aquifers by partial differential equations are identified. These are, to determine (1) parameters, (2) initial conditions, (3) boundary conditions, (4) inputs, and (5) a mixture of the above. Various methods to solve these inverse problems are reviewed, including those from fields other than hydrology. A new direct method to solve the inverse problem (DIMSIP) is then developed. Basically, this method consists of transforming the partial differential equations of flow to algebraic equations by substituting in them the values of the various derivatives of the dependent variable (which may be hydraulic pressure, chemical concentration or temperature). The parameters are then obtained by formulating the problem in a nonlinear optimization framework. The method of sequential unconstrained minimization is used. Spline functions are used to evaluate the derivatives of the dependent variable. Splines are functions defined by piecewise polynomial arcs in such a way that derivatives up to and including the order one less than the degree of polynomials used are continuous everywhere. The natural cubic splines used in this study have the additional property of minimum curvature which is analogous to minimum energy surface. These and the derivative preserving properties of splines make them an excellent tool for approximating the dependent variable surfaces in groundwater flow problems. Applications of the method to both a test situation as well as to real-world data are given. It is shown that the method evaluates the parameters, boundary conditions and inputs; that is, solves inverse problem type V. General conditions of heterogeneity and anisotropy can be evaluated. However, the method is not applicable to steady flows and has the limitation that flow models in which the parameters are functions of the dependent variable cannot be calibrated. In addition, at least one of the parameters has to be preassigned a value. A discussion of uncertainties in calibration procedures is given. The related problems of model validation and sampling of aquifers are also discussed.
    • Calibration of a non-null interferometer for aspheric testing.

      Lowman, Andrew Everett.; Greivenkamp, John; Sasian, Jose; Shannon, Robert R. (The University of Arizona., 1995)
      Aspheric surface testing would be greatly expedited by eliminating the need for a null condition. To test in a non-null configuration, an interferometer must be capable of measuring steep wavefronts. These wavefronts contain aberrations introduced by the interferometer optics, so non-null measurements must be calibrated. Sub-Nyquist interferometry (SNI) enables measurement of large wavefronts. A simple Twyman-Green interferometer was constructed to conduct SNI and to explore the calibration problem. The characteristics of the interferometer were investigated, and wavefronts with several hundred waves of departure from a reference sphere were recorded and successfully reconstructed. A defocused sphere was used to demonstrate the need for calibration and to serve as a test subject for the calibration study. Reverse optimization was used to calibrate wavefront measurements. Experimental wavefront data were entered into the merit function of a lens design program, and optimization was employed to retrieve the prescription of the interferometer and the part shape. To simulate interference in the design program, the reference wavefront was stored in a Zernike phase surface on the image plane. The multiple configuration mode of the program was utilized to optimize several test configurations simultaneously, providing additional information to overcome a global optimization problem and to remove uncertainty in the part alignment. Errors introduced by pupil distortion were avoided by moving the stop to the plane of the sensor in the design program. Measurements from a defocused sphere were successfully calibrated using reverse optimization. A surface departure of 100λ was calibrated to better than λ/4 PV. Because the interferometer could not be characterized sufficiently for calibration of measurements from aspheres, simulations were conducted. A lens design program was used to develop an accurate model of an interferometer, including simulated fabrication, alignment, and characterization errors. Reverse optimization was applied using wavefronts generated by the model. Testing was simulated for several conic asphere surfaces. Reverse optimization yielded calibration to λ/4 PV for conic aspheres with surface departures as large as 300λ. The results suggest that it is feasible to calibrate non-null measurements of aspheric surfaces using reverse optimization.

      Cheatham, Patrick S. (The University of Arizona., 1976)
    • Calibration of psychological measures: An illustration of three quantitative methods

      Sechrest, Lee; McKnight, Patrick Everett, 1966- (The University of Arizona., 1997)
      The scores or metrics from psychological measures are rarely interpretable. Uninterpretable metrics result in poorly understood psychological research findings. In response to this problem, several methods are proposed that render metrics more meaningful. The methods employed are calibration procedures. Three calibration procedures are illustrated that prove to be extremely powerful in making the metrics of two related measures more understandable. Establishing the behavioral implications of the scores, computing just noticeable differences, and calibrating between measures are the three procedures described and illustrated. For the purposes of illustration, two measures of Attention Deficit Hyperactivity Disorder (ADHD) are used in the calibration procedures. These two measures are often used interchangeably without regard to their relationship with one another. The three procedures and the results of each are discussed in detail.
    • Call versus continuous auctions: An experimental study of market organization.

      Smith, Vernon L.; Van Boening, Mark Virgil.; Cox, James C.; Oaxaca, Ronald L. (The University of Arizona., 1991)
      The results from 17 new experiments and 19 previously reported experiments are compared in an investigation of call and continuous auctions. The call auction used is the computerized PLATO sealed bid/offer (SBO), uniform price auction. The continuous auction used is the PLATO double auction (DA), a computerized version of the "open outcry" double auction. The SBO call auction has temporal consolidation of market orders and has limited information about trading activity. The continuous DA auction is characterized by sequential bilateral trades, and trading information (bids, offers, and prices) is publicly displayed. The paper first explores the effect of multiple crossings per trading period in the SBO call auction. Next, a comparison of SBO and DA is made, based on market experiments using flow supply and demand schedules. The institutional comparison is then extended to experimental asset markets. The results imply the following. First, multiple calls per period increase the efficiency of the SBO call auction, relative to one call per period, but they also induce greater misrepresentation of costs and values in the first crossing each period. Buyers and sellers also withhold units from the first crossing in a further attempt to gain strategic advantage. However, neither the withholding nor the misrepresentation appears to have any substantial influence on price. Second, the SBO auction with two calls per period is as efficient as the DA auction. In markets with a random competitive equilibrium (CE) each period, the SBO auction does a better job than DA at tracking the random CE price. Thus the SBO auction is equally as efficient as the DA, and has the further attributes of lower price volatility and greater privacy. Third, in laboratory asset markets, the SBO auction exhibits price bubbles similar to those observed in DA markets. Price dynamics in the two institutions are comparable, despite the stark differences in order flow and information dissemination.

      Joehnk, Michael D. (The University of Arizona., 1971)
    • The calpain system and postmortem tenderization in ovine meat from callipyge and normal phenotypes

      Marchello, John A.; Delgado, Eduardo Francisquine (The University of Arizona., 1998)
      In an attempt to further our understanding of the relationship between the calpain system and postmortem tenderization, three muscles [biceps femoris (BF), infraspinatus (IS), and longissimus (LD)] from normal (N = 6) and callipyge (N = 6) sheep were studied. Callipyge is a genetic phenomenon where carriers of the callipyge gene present a hypertrophy of pelvic and torso muscles, such that BF and LD are affected while IS is not. It has been observed characteristically that calpastatin and m-calpain activities are increased in muscles of animals affected by the callipyge phenotype. Soluble calpain and calpastatin, and myofibril-bound μ-calpain activities, and myofibrillar fragmentation index (MFI) were determined at death, 1d, 3d and 10d postmortem. Sarcomere length was determined at 1d and 10d postmortem. Shear force of the longissimus muscle was determined at 1d, 3d and 10d postmortem. Western blots for calpastatin, μ-calpain, desmin, nebulin, titin, troponin-T and α-actinin were performed to follow the degradation pattern of those proteins. The calpastatin and m-calpain activities were more than two-fold greater in BF and LD muscles from callipyge than in the same muscles from normal animals. Calpastatin activities in infraspinatus muscle from normal animals were higher than in the other two muscles of this phenotype. Soluble μ-calpain activities were higher at death for normal phenotype in BF and IS muscles and it decreased rapidly during postmortem storage. However, the rate of this decrease in that activity was faster in normal than in callipyge phenotype. Myofibrils contained calcium dependent protease activity and this activity was inhibited by cysteine proteases inhibitors and by calpastatin to some degree. There was no difference in the myofibril-calcium dependent protease activity between phenotypes at any time postmortem, presenting lower activity at death. The magnitude of protein degradation and tenderization were assessed by MFI and shear force, respectively. Neither the MFI nor shear force changed appreciably during storage of the callipyge affected muscles. Calpastatin level seems to determine the rate of postmortem tenderization.
    • Calpains in skeletal muscle: Generation of an inhibitory overexpression system and analysis of degradation in simulated microgravity

      Antin, Parker B.; Grill, Mischala Ann (The University of Arizona., 2003)
      Muscle atrophy is a serious side effect seen with extended time in space. Proteolytic degradation of specific muscle proteins leads to smaller, weaker muscles that are structurally more susceptible to damage. Calpains are proteases that specifically degrade target proteins of the myofibril, and have been implicated in many types of muscle atrophy. Calpain activity is regulated by a combination of activation by calcium and inhibition by calpastatin, its endogenous inhibitor. This dissertation describes the generation of a skeletal muscle-specific, doxycycline (Dox) controlled, calpastatin over-expression system in transgenic mice to regulate calpain activity. A dual construct system, the transactivator line utilizes an optimized tet-on system and a modified muscle creatine kinase promoter to create muscle specific expression of a tet transactivator. The second transgenic line, consisting of a bi-directional promoter centered on a tet responder element controlling both a luciferase reporter gene and a tagged calpastatin, is transcriptionally silent until activated by a dox induced transactivator molecule. Compound hemizygous mice showed high level, Dox dependent, muscle-specific overexpression of luciferase and transgenic calpastatin, demonstrating the effectiveness and flexibility of the tet-on system to provide a tightly regulated overexpression system in adult skeletal muscle. Consistent overexpression of calpastatin was hard to maintain, however, and not all of the proposed experiments could be achieved. Additional studies compared the degradation of hindlimb suspended mouse muscle proteins (weightlessness model) to those of ground control muscle proteins briefly incubated in Ca²⁺ (to initiate calpain degradation). Four proteins known as targets for calpain degradation were selected for analysis. Degradation responses of myofibrillar proteins titin, nebulin, and troponin T in hindlimb suspension clearly mimicked that seen with the calcium incubations. The cytoskeletal calpain target protein, desmin, however did not respond the same to both treatments showing moderate degradation with calcium and no degradation with hindlimb suspension. These data suggest that myofibrillar calpain target proteins, but not necessarily cytoskeletal proteins, are rapidly targeted for degradation in hindlimb suspension in a manner similar to that induced by calcium, implicating calpain as a mediator of this degradation.
    • The Cambrian and Devonian carbonate rocks at Yampai Cliffs, Mohave County, Arizona

      Wood, William Hulbert, 1911- (The University of Arizona., 1955)
    • Campus activism: Studying change as it is being created Gender, the Internet, and organizational structure in a student anti-sweatshop group

      Slaughter, Sheila; Ginter, Mary Beth (The University of Arizona., 2003)
      In this case study of an Anti-Sweatshop Group, on the campus of a university in the southwest, I present findings related to gender, the Internet and organizational structure and discuss these in connection with the group's mission, behaviors, activities and perceptions. This is an exploratory, qualitative case study that spanned nine-months of ethnographic field work. Through interviews, participation and observation of group meetings throughout a nine-month period, and analysis of over 1000+ listserve emails from that same period of time, I explored the lived experiences of a campus activist group and learned how they perceived gender issues, Internet usage and organizational structure.
    • Campylobacter jejuni in gastroenteritis: Detection and mechanisms of intracellular survival

      Joens, Lynn A.; Day, William Alan, 1964- (The University of Arizona., 1998)
      The fastidious bacterium Campylobacter jejuni has recently been identified as a leading cause of human bacillary enteritis. Delays in recognition of this important pathogen reflect inadequate isolation techniques, which cannot recover environmentally stressed viable but non-culturable forms. Therefore, a non-culture based detection systems for C. jejuni would be invaluable. Studies were undertaken to develop a PCR based detection assay for C. jejuni. Fingerprints enriched for repetitive C. jejuni chromosomal elements were generated using arbitrarily primed PCR. Dot blot screening of fingerprint products for specificity to C. jejuni identified a 496 bp product which hybridized with all C. jejuni isolates examined. No binding to other Campylobacter species or enteric genera screened was observed. The product was cloned, sequenced, and primers synthesized to three overlapping regions of the probe. A primer pair was identified which directs amplification of a 265 bp product from C. jejuni alone. Sensitivity studies demonstrated that the C. jejuni specific PCR generated product from as few as 100 lysed bacteria. The ability of C. jejuni to penetrate normally non-phagocytic host cells is believed to be a key virulence determinant. Kinetics of C. jejuni of intracellular survival have been described and indicate that the bacterium can persist and multiply within epithelial cells and macrophages in vitro. Studies by Pesci et al. demonstrate that super-oxide dismutase contributes to intra-epithelial cell survival, suggesting that bacterial factors which combat reactive oxygen species enable the organism to persist inside host cells. Experiments were conducted to determine the contribution of catalase to C. jejuni intracellular survival. The gene encoding catalase (katA) was cloned via functional complementation, sequenced, and isogenic katA mutant strains constructed. Kinetic studies of bacterial viability indicate that catalase provides resistance to hydrogen peroxide in vitro but does not have a role in intra-epithelial cell survival as growth curves for katA mutant and wild type strains generated from long term culture within HEp-2 cells are roughly identical. Catalase does however contribute to intra-macrophage survival as katA mutants were recovered from cultured peritoneal macrophages at significantly reduced numbers (p = 0.00246) relative to the wild type strain after 72 hr incubation with these cells.

      Kurzer, Paulette; Achilov, Dilshod; Kurzer, Paulette; Zheng, Zhiping; Ragin, Charles; Hudson, Leila (The University of Arizona., 2010)
      This dissertation investigates the extent to which between Islam and democracy are compatible in the Muslim world. While some scholars have argued that Islam is inherently incompatible with democracy many have found, in contrast, that Islam has many resources to accommodate a successful democratic state. If Islam is compatible with democratic governance at a doctrinal level, why then are the majority of Muslim countries largely authoritarian? To address this question, I introduce a refinement on this discrepancy by focusing on the coexistence of emerging Islamic institutions with democratic transitions in 49 Muslim-majority states. Traditionally, Islam has been operationalized as a "dichotomous" variable based on demographics or an "attitudinal" measure based on survey responses. Both measures have failed to account for an inherent variation of Islam's role across the Muslim world. I developed a new index to assess the variation in Islam factor across Muslim countries: Islamic Institutionalization Index (III). This new index avoids the shortcomings of the current approaches to quantifying "Islam" and captures the range of variation in Islamic Institutions across 49 countries by allowing scholars to gauge the density and level of Islam in each country. With the index I designed, I rely on three different levels of analysis to examine under which circumstances Islam and democracy can coexist. More precisely, by looking into three categories of Islamic institutions (educational, political, and financial), I raise the following question: "To what extent and in what levels do Islamic Institutions support the coexistence between Islam and Democracy?"Analyzing 49 Muslim-majority states, I utilize mixed methodology by using Configurational Fuzzy-Set Qualitative Comparative Analysis (FS/QCA) and focused case study analysis. FS-QCA offers an innovative and robust approach to identify configurationally complex factors while discerning the emerging patterns displayed by medium size (N=49) cases. To further explain the complex interplay of conditions, I focus on two case studies in greater detail: Kazakhstan and Turkey. I find a strong empirical association between the density and scope of Islamic political, educational and financial institutions and the existence of democratic norms (civil and political liberties and democratic institutions). Findings further suggest that Islamic institutions can coexist with civil and political liberties when governments allow Islamic institutionalization to function in society with no stern political restrictions. Among the three categories of III, Islamic states with higher levels of Islamic political institutions manifest particularly higher levels of democracy. Conversely, states that ban the emergence of a range of Islamic institutions in politics, education, and interest-free banking exhibit low levels of freedom and stunted democratic institutions.
    • Can Purchases Make Us Happier? Perhaps, if We Tell Others about Them

      Brucks, Merrie; Bastos, Wilson; Levy, Sidney J.; Janakiraman, Narayan; Stone, Jeff; Mehl, Matthias (The University of Arizona., 2013)
      The question of what type of purchase (i.e., experiential vs. material) typically advances more happiness has been answered (Van Boven and Gilovich, 2003). This dissertation employed three different manipulation methods across six studies to investigate what underlies this effect. A consistent pattern of results demonstrated that verbal sharing (i.e., telling others) helps explain the superiority of experiential purchases in advancing happiness. Moreover, I found that people's greater inclination to share about their experiential (vs. material) purchases is driven by their expectation of being more highly regarded by their listeners. Taken together, these findings shed light on a behavioral (i.e., sharing) and psychological process (i.e., expected regard) that help us understand why experiences make people happier than do material objects.
    • Can Semantic Activation Affect Figure Assignment?

      Peterson, Mary A.; Mojica, Andrew Joseph; Peterson, Mary A.; Scalf, Paige; Ryan, Lee (The University of Arizona., 2014)
      Figure assignment entails competition between object properties on opposite sides of borders. The figure is perceived on the side of the border that wins the competition. Ample evidence indicates that configural familiarity is among the competing object properties. We investigated whether priming the semantics of a familiar object suggested along one side of a border can increase its likelihood of winning the competition. To prime the semantics, we presented brief masked exposures of object names before brief masked exposures of displays where a portion of a familiar object was suggested on one side of a central border separating two equal-area, black-and-white regions. Participants reported whether the figure lay on the left or right side of the central border and were unaware of the presence of the word prime. These experimental primes named either the Same Object (SO) or a Different Object (DO) as the familiar object suggested in the display. In the DO condition, the word named an object either in the Same Category (DO-SC) or a Different Category (DO-DC) as the familiar object suggested in the display, where superordinate category was defined as natural versus artificial objects. We also used non-words as control primes. We hypothesized that, if semantic activation influences figure assignment, participants in the SO and DO-SC conditions should be more likely than participants in the DO-DC condition to perceive the figure on the side where the familiar object lies following experimental primes than control primes. We did not observe differences between experimental and control prime in any condition. However, we did obtain a Prime Context Effect, in that participants were more likely to perceive the figure on the familiar side of the border in the SO and DO-SC conditions than in the DO-DC condition. The Prime Context Effect shows that participants discerned the relationship between the masked word prime and the semantics of the familiar object suggested in the display, and this led them to change their strategy on both experimental and control trials. We also found that behavior changed over the course of the experiment: Participants in the DO-DC condition perceived the figure on the familiar side of the border more often in the second half of the experiment, on both experimental and control trials. This pattern suggests that over the course of the experiment, they learned to rely more on information from the display than from the prime, perhaps by restricting their attention to the time when the figure-ground display appeared. Participants in the DO-SC condition perceived the figure on the familiar side of the border more often on experimental trials in the second half of the experiment, whereas their performance on control trials did not differ in the first and second half. We hypothesize that participants in the DO-SC condition learned to match the superordinate semantics of the experimental prime and the display, leading to semantic priming. Taken together, these results show that (1) participants can quickly learn the relationship between experimental primes and target displays and can change their strategy accordingly, and (2) semantic activation can affect figure assignment.

      Levin, Joel R.; Marley, Scott C.; Levin, Joel R.; D'Agostino Jerry; Glisky, Elizabeth (The University of Arizona., 2005)
      The present study extends previous research on motoric activity and imagery production to the text processing of Native American learning-disabled students and third-grade regular-education students. Two experiments were developed to test predictions derived from Glenberg's (1997) "indexical hypothesis". Experiment 1 was performed with learning-disabled Native American students listening to narrative passages under one of three randomly assigned listening strategies: free-study, visual, and manipulate. Experiment 2 was performed with regular-education Native American third graders reading similar passages under one of three randomly assigned reading strategies: reread, observed manipulation, and manipulation. With the learning-disabled students, statistically significant improvements in memory for story events, locations, objects, and actions were observed on cued- and free-recall outcomes when toys representing story characters and settings were present during encoding. Facilitative strategy transfer was not apparent when the toys were removed. With the third-grade students, similar benefits were found when the toys were present. In addition, students who had access to the toys during a training period performed significantly better on cued- and free-recall measures relative to reread students when the toys were no longer present.
    • Can we level the playing field? The effects of ease of denial on psychological reactions to threat for people with high and low self-esteem

      Greenberg, Jeff L.; Schimel, Jeff (The University of Arizona., 2001)
      A good deal of research suggests that high self-esteem individuals cope with failure by engaging in self-serving biases that allow them to deny the negative implications of failure. If high self-esteem individuals cope successfully with failure through a process of denial, then making it easier for low self-esteem individuals to deny negative feedback might allow them to cope successfully with failure too. To test this notion, high and low self-esteem participants took a test of creativity and were given feedback that they were either creative or non-creative. Following this procedure, the ease of denial of the feedback was manipulated by telling the participants that the creativity test was either highly valid or invalid. Participants' evaluations of the test, positive and negative mood, and self-ratings on creativity were then assessed. It was expected that high self-esteem participants would generally make more self-serving evaluations of the test than low self-esteem individuals, and as a result, experience more pleasant affect and view themselves more positively on creativity than low self-esteem individuals following negative feedback. However, it was also expected that if the negative feedback was easy to deny, low self-esteem individuals would be just as self-serving as high self-esteem individuals in their evaluations of the test and experience a similar increase in positive mood, and rate themselves higher on creativity. The results did not support these predictions. Both high and low self-esteem individuals made self-serving evaluations of the test regardless of the ease of denial manipulation. Limitations of the current research and directions for future research are discussed.
    • A canal irrigation water allocation model.

      Slack, Donald C.; Larson, Dennis L.; Akhand, Md Nurul Alam.; Thompson, Gary D.; Wilson, Paul N.; Roth, Robert L. (The University of Arizona., 1992)
      A water allocation model was developed to assist with allocation of canal water to competing crop irrigation demands. Multi-period linear programming was utilized to optimally allocate water in both time and space to maximize benefits for an irrigated farm. Irrigation scheduling, crop response and canal water delivery models were used to support the water allocation decisions. The irrigation scheduling model supplied information on crop evapotranspiration and soil water storage. The crop response model predicted crop yield in response to the irrigation water applications. The canal delivery model checked the feasibility of supplying the allocation quantities through the control structures and turnouts. The allocation model was evaluated by tests of water allocation for the University of Arizona, Maricopa Agricultural Center demonstration farm. In crop scenarios which emphasized cotton production, the model recommended deficit irrigation for the barley, cotton, grapes and wheat fields during periods when the quantity of irrigation water demanded was greater than that supplied. Analysis of the effects of changes in water cost and crop returns showed the basis of the solution remained unchanged for a wide range of data. The basis was, however, found to be unstable with very limited water supplies. In addition to serving as a planning tool, the allocation model could be used as a real time management tool. It is believed to have broad applicability to other irrigation projects in other areas with characteristics similar to Arizona test conditions.
    • Cancer Capacity and Resources in Rural Arizona

      Calhoun, Elizabeth A.; Lent, Adrienne; Jacobs, Elizabeth T.; Barraza, Leila (The University of Arizona., 2020)
      Background: Cancer is the second leading cause of death in the U.S. Rural urban cancer disparities exist nationally and in Arizona. Previous studies on the availability of rural cancer services are cancer-specific, limited to specific points along the cancer care continuum (e.g., screening, diagnosis, or treatment), or require updating to capture the current landscape as it relates to rural health. This study explored the following three aims: 1) Describe the availability of cancer capacity and services for breast, cervical, colorectal and lung cancer across the cancer care continuum in low populous counties in Arizona; 2) Evaluate the association between breast cancer capacity and resources with breast cancer incidence and mortality; and 3) Provide policy recommendations focused on increasing capacity and resources in low populous, rural counties in Arizona. Methods: For Aim 1, a cancer capacity and resources survey was developed and distributed to healthcare organizations operating outside of Arizona’s largest population centered counties, Maricopa and Pima. Numbers of healthcare providers were pulled from the Center for Medicare and Medicaid Services. Numbers of clinical sites and healthcare providers were converted to county-level per capita rates. Rural Urban Continuum (RUC) codes were used to designate county metropolitan status. County demographic information from the U.S. Census Bureau, income data from the US Bureau of Economic Analysis, and unemployment rates from the US Department of Labor were included. Descriptive statistics were used to summarize the results. A student’s t-test was used to evaluate differences between rural and urban counties. For Aim 2, the Arizona Department of Health Services Cancer Registry provided county level cancer incidence and death rates from 2010 through 2016. Linear regression was used to evaluate the association between rural status and breast cancer capacity and services with breast cancer incidence and mortality rates. For Aim 3, current US federal and state level policies focused on increasing the rural workforce were reviewed. Results: Out of Arizona’s 15 counties, 13 were represented. Six were urban (RUC codes 1 – 3) and seven were rural (RUC codes 4 – 7). Urban counties had a larger average population (216,773) than rural counties (49,507) (p-value = 0.01). Rural counties had more per capita clinical sites (20.4) than urban counties (8.9) (p-value = 0.02). Rural counties had more per capita cervical cancer screening sites (18.9) than urban counties (7) (p-value = 0.02) and rural counties had more per capita colorectal cancer screening sites (15.7) than urban counties (2.5) (p-value = 0.02). Urban counties had more per capita gastroenterologists (2.2) than rural counties (0) (p-value = 0.02) and urban counties had more per capita pathologists (1.0) than rural counties (0) (p-value = <0.01). Rural counties had zero medical oncologists. Per capita, rural counties with RUC codes 4 and 6 had hematology and oncology physicians (0.3, 2.5) and radiologists (2.8, 6.0) but those with RUC code 7 had zero. Although not significantly different, rural counties with RUC code 6 had three times as many per capita registered nurses (306.7) than urban counties (90.8). Rural county status was associated with a decrease in breast cancer incidence (β = -20.1, 95% CI: -37.2, 3.1). There was no association between breast cancer incidence and county per capita sites providing breast cancer screening (β = -8.8, 95% CI: -23.9, 6.9), diagnosis (β = -5.2, 95% CI: -22.2, 11.7), treatment (β = -6.5, 95% CI: -23.2, 10.2), and all three services (β = -8.0, 95% CI: -23.9, 7.9) or county per capita primary care physicians (β = 0.0, 95% CI: -0.54, 0.48), hematology oncology physicians (β = -0.9, 95% CI: -15.7, 13.8), medical oncology physicians (β = 35.2, 95% CI: -22.7, 93.0), OBGYN physicians (β = -0.5, 95% CI: -4.2, 3.2), radiologists (β = -0.2, 95% CI: -6.8, 6.4), and surgeons (β = 1.6, 95% CI: -3.1, 6.3). In the unadjusted model, rural RUC codes four (β = -24.1, 95% CI: -41.8, -6.4) and six (β = -32.6, 95% CI: -53.0, -12.2) were associated with breast cancer incidence. There was no association between breast cancer incidence and RUC code 7 (β = -1.8, 95% CI: -22.3, 18.6). In the model adjusted for race (percent of the county population that’s Hispanic) and Ethnicity (percent of the county population that’s American Indian and Alaska Native), RUC codes four (β = -19.0, 95% CI: -37.7, -0.4) and six (β = -32.6, 95% CI: -56.0, -7.9) were associated with breast cancer incidence. There was no association between breast cancer mortality and rural county status (β = -1.1, 95% CI: -7.7, 5.6), county per capita sites providing breast cancer screening (β = -0.2, 95% CI: -4.2, 3.8), diagnosis (β = 0.4, 95% CI: -3.8, 4.6), treatment (β = 0.4, 95% CI: -3.9, 4.6), all three services (0.2, -3.9, 4.3) or county per capita primary care physicians (β = 0.0, 95% CI: -0.1, 0.0), hematology oncology physicians (β = -1.6, 95% CI: -5.3, 2.1), medical oncology physicians (β = -0.9, 95% CI: -17.2, 15.3), OBGYN physicians (β = -0.6, 95% CI: -1.5, 0.3), radiologists (β = -0.7, 95% CI: -2.4, 1.0), and surgeons (β = -0.1, 95% CI: -1.4, 1.2). Conclusions: While rural counties may have more physical infrastructure, they lack specialists integral to providing cancer services. Non-physician clinical providers may be more prevalent in rural areas and represent opportunities for improving cancer care. Compared to urban counties, rural county status was associated with lower breast cancer incidence rates but not associated with breast cancer death. The number of sites delivering breast cancer services and physicians were not associated with breast cancer incidence or mortality at the county level. Other factors may contribute to rural urban differences in breast cancer incidence. Federal and state level policies have been effective in increasing the rural healthcare workforce. However, opportunities for improving rural cancer care through policies and programs exist. Improved data collection and availability from state level workforce data and the FDA mammography database can help improve cancer capacity research. Increased exposure to rural locations during residency, transformation of GME payment, and expansion of loan repayment and scholarship programs may help increase the number of specialists delivering cancer care in rural Arizona and nationally. Increased training opportunities and the scope of work expansions for non-physician clinicians and advanced practice providers may help improve the delivery of cancer prevention and treatment services in rural areas that lack specialist physicians. Future research should explore these factors as well as the association between cancer capacity and resources at a more local level since Arizona counties can be a heterogeneous unit of observation.