Now showing items 19766-19785 of 20306

    • Utilizing Environmental Analytical Chemistry to Establish Culturally Appropriate Community Partnerships

      Briehl, Margaret; Ingram, Jani C.; Credo, Jonathan; Gachupin, Francine; Warneke, James (The University of Arizona., 2022)
      In the United States, minority communities are disproportionately exposed to environmental contaminants due to a combination of historically discriminatory based racial policies and a lack of social political capital. Within this demographic, American Indian/Alaskan Native (AI/AN) communities have additional factors that increase the likelihood of contaminant exposure. Some of these factors include the disparity of social, cultural, and political representation, differences in cultural understandings between AI/AN communities and western populations, and the unique history of tribal sovereignty in the US. Research from both private and federal organizations starting in the 1990s led to a change in research agendas that emphasized a push to conduct research with AI/AN communities. However, although many research pursuits may be rooted in beneficence, the rift in cultural upbringing can lead to negative outcomes as well as further isolation and misrepresentation of AI/AN communities. Arguably the most significant example of this breakdown is the Havasupai v Arizona Board of Regents case surrounding the misuse of Havasupai blood samples. The outcome of this case led to many Tribal Nations around the United States increasing their distrust of outsiders, regardless of their organizational affiliation. Despite this sobering example, collaborations with AI/AN communities need not be difficult or tempestuous. However, it does require a change in the existing western scientific approach to both community collaborations as well as how science is viewed. Simply put, researchers must work to overcome the initial distrust many Tribal Nations have towards outsiders, and this attitude must be maintained throughout the duration of the partnership. Some obstacles to collaboration include the amount of time and resource allocation as well as identifying the most culturally appropriate methodology while maintaining scientific rigor. Instead of viewing these hurdles as nuisances, western scientists should view them as challenges and the opportunity to adapt their approaches while still maintaining rigorous and reproducible science. An achievable change in heuristics is to approach these type of collaborations as if one is forging a healthy friendship with another individual. This dissertation exemplifies the benefits of adopting these approaches and outlines four years of effort to secure enough trust with two Tribal Nations, the Cocopah and the Colorado River Indian Tribes, to be allowed to conduct a pilot study within their Tribal lands in full collaboration with their governing body. As part of that four years, in addition to numerous in-person and virtual meetings, preliminary data was gathered to demonstrate the potential harm of environmental contaminants to the Tribal population. It should be noted, although there are similarities in the approved methodologies for the pilot grants with the Tribes, they are distinctly different but still address the underlying concerns of the Tribes. This versatility is one of the hallmark benefits of utilizing environmental analytical chemistry in this capacity. Specifically, it allows researchers numerous modalities to investigate the root causes of the environmental concerns a Tribal Nation may have and can be modified to be unique for each community.
    • Utilizing integrity constraint knowledge in heterogeneous databases: A methodology for schema integration and semantic query processing.

      Venkataraman, Ramesh.; Ram, Sudha; Nunamaker, Jr., J. F.; Pingry, David E. (The University of Arizona., 1995)
      Information sharing among databases requires the development of techniques for accessing data from multiple heterogeneous databases. One approach to providing interoperability among these databases, is to define one or more schemas representing a coherent view of the underlying databases. A review of existing research on schema integration, the process of generating integrated schemas, points to the need for development of techniques for identifying objects in multiple databases that may be related. The development of efficient mechanisms for accessing heterogeneous databases is another issue that has received very little attention in the literature. This dissertation describes a seven step methodology for utilizing integrity constraint knowledge from multiple heterogeneous databases. The methodology extends traditional approaches to schema integration by proposing additional steps that describe how integrity constraints can be used, in a heterogeneous database environment, to improve the interschema relationship identification process and generate additional semantics, in the form of integrity constraints, at the integrated schema level. The dissertation introduces the concept of constraint-based relationships among objects in heterogeneous databases and describes how these relationships can be used to integrate integrity constraints specified on heterogeneous databases. The dissertation also elaborates on how these integrated integrity constraints can be used to facilitate semantic query processing in a heterogeneous database environment. The description of a system that implements the various phases of the methodology is also presented. A unique feature of the system is that it uses blackboard architectures to facilitate the human-computer interaction needed during schema integration. A simulation study that shows the potential benefits of performing semantic query processing, in a heterogeneous database environment, using the integrated integrity constraints generated by our methodology is also presented.

      Barnes, William Donald; Siner, Pat; Barnes, William Donald; Clark, Donald C.; Allen, Paul M.; Mishra, Shitala P.; Gavlak, Emil S. (The University of Arizona., 1985)
      This study focused on a single alternative school program with a strong outdoor component and featuring a theoretical and practical orientation very much concerned with personal relationships. Data were sought regarding this program with the intent of developing possible formats for alternative school programs. The case study approach was employed to gather and report data. It permitted the investigator to observe, interact, and record the multiple phenomena. The Theory of Personal Process was the framework utilized to observe the relationships between student and teacher. This theory was made up of five key words: (1) Contact, (2) Consult, (3) Find, (4) Share, and (5) Accompany. The study detailed the personal school relationships of the students and teacher. The investigator, as participant/observer, was the instructor of each of the five students. The investigator maintained records of interaction with the students. Furthermore, he had access to journals, term papers, and other written materials produced by the students. Each case study was presented as a specific phase of the alternative school. A specific student was described as he interacted with others in that phase of the program. The description of the student's relationship with the teacher was also correlated to the Theory of Personal Process. Optional formats for alternative school programs were developed from the case studies. The program featured the following phases: (1) Orientation, (2) Group, (3) Outdoor Experiences, (4) Classroom, (5) Creativity, and (6) Community. The key to the success of each phase was determined to be the relationship between the teacher and student. This relationship fostered a support basis for the student which, in turn, provided the necessary freedom to learn. The school was not so much an educational unit as it was a social unit, a "family."
    • Utilizing S2 Cells to Study the Molecular Mechanisms Regulating Centriole Duplication

      Rogers, Gregory; Nye, Jonathan; Rogers, Gregory; Krieg, Paul; Weinert, Ted; McDermott, Kimberly; Lybarger, Lonnie (The University of Arizona., 2014)
      Centrosomes are complex organelles consisting of a pair of small microtubule based structures called centrioles embedded in an amorphous cloud of pericentriolar material (PCM). These organelles are critical for proper mitotic spindle assembly and orientation, and can also migrate to the plasma membrane where, as basal bodies, they serve to nucleate cilia¹. Centrioles are the core duplicating elements of the centrosome and, similar to DNA, duplicate once per cell cycle during S-phase². Errors in this process can lead to a cell that contains too many or too few centrosomes and are thought to promote tumorigenesis by directly promoting genomic instability and loss of polarity in stem cells³⁻⁷. Polo-like kinase 4 (Plk4) and Asterless (Asl) are both essential for centriole duplication to occur and overexpression of either of these proteins leads to cells that contain too many centrosomes, a condition known as centrosome amplification. Interestingly, both of these proteins also have the unique ability to promote de novo formation of centrioles in cells that normally lack centrioles⁸⁻¹⁴. Plk4 is a member of the Polo-like kinase family of proteins and is named after the founding member Drosophila Polo¹⁵. In humans, there are four members (Plk1-4) that all share sequence similarity and an N-terminal ser/thr kinase domain. Plk's 1-3 all contain two characteristic Polo box (PB) motifs, downstream of the kinase domain, that consist of a six stranded β-sheet lying across a C-terminal α-helix¹⁶. However, Plk4 was thought to be unique among family members since it only contained one C-terminal PB domain and a larger cryptic polo box domain that showed very little sequence similarity to known PBs. However, we performed an in-depth structure/function analysis of this cryptic polo box region and were able to determine, through x-ray crystallography, that Plk4 is unique among Plk family members not because it contains one PB domain but, in fact, because it contains three polo box domains. Thus, the cryptic polo box domain contains two previously unidentified polo boxes, termed PB1-PB2, upstream of the C-terminal PB3¹⁷. Furthermore, we found that PB1-PB2 is necessary for proper localization of Plk4 and that the entire PB1-PB2 cassette is necessary for binding to Asl. Our results also indicate that the PB1-PB2 domain plays a critical role in regulating Plk4 autophosphorylation and degradation, in order to restrict centriole duplication to once and only once per cell cycle. Previously Asl has been shown to be not only a binding partner of Plk4 but also a substrate for Plk4 kinase activity, however, the functional significance of this phosphorylation has remained elusive⁹. Our work has shown that Asl phosphorylation by Plk4 is conserved from flies to humans and is restricted to the N-terminal (Asl-A) region. In total we identified 13 phosphorylated residues via mass spectrometry. Analysis of phosphorylation mutant constructs revealed that Plk4 and Asl are involved in a novel feedback loop controlling centriole duplication. This feedback loop consists of two important features: first, Asl oligomerization stimulates Plk4 kinase activity and thus promotes centriole duplication and second, the Asl-A region can be phosphorylated by Plk4, preventing further Asl oligomerization, which in turn limits the amount of active Plk4. We propose that this feedback loop is a crucial step in limiting a mother centriole to only one daughter per cell cycle. This work represents a significant advance in our understanding of the processes that govern the centriole duplication pathway and specifically the structure and function of two critical components, Plk4 and Asl. A detailed understanding of the molecular mechanisms controlling centriole biogenesis is an essential first step in our goal of understanding their role in tumorigenesis and may serve as a guide for future studies focused on targeting this pathway for the prevention or treatment of cancer.
    • Utilizing Social Bookmarking Tag Space for Web Content Discovery: A Social Network Analysis Approach

      Ram, Sudha; Wei, Wei; Ram, Sudha; Zeng, Daniel; Amir, Rabah (The University of Arizona., 2010)
      Social bookmarking has gained popularity since the advent of Web 2.0. Keywords known as tags are created to annotate web content, and the resulting tag space composed of the tags, the resources, and the users arises as a new platform for web content discovery. Useful and interesting web resources can be located through searching and browsing based on tags, as well as following the user-user connections formed in the social bookmarking community. However, the effectiveness of tag-based search is limited due to the lack of explicitly represented semantics in the tag space. In addition, social connections between users are underused for web content discovery because of the inadequate social functions. In this research, we propose a comprehensive framework to reorganize the flat tag space into a hierarchical faceted model. We also studied the structure and properties of various networks emerging from the tag space for the purpose of more efficient web content discovery.The major research approach used in this research is social network analysis (SNA), together with methodologies employed in design science research. The contribution of our research includes: (i) a faceted model to categorize social bookmarking tags; (ii) a relationship ontology to represent the semantics of relationships between tags; (iii) heuristics to reorganize the flat tag space into a hierarchical faceted model using analysis of tag-tag co-occurrence networks; (iv) an implemented prototype system as proof-of-concept to validate the feasibility of the reorganization approach; (v) a set of evaluations of the social functions of the current networking features of social bookmarking and a series of recommendations as to how to improve the social functions to facilitate web content discovery.
    • Utilizing Video Education to Increase Knowledge and Awareness of Perinatal Anxiety and Depression

      Gregg, S. Renee; Ketterer, Mallory; Kiser, Lisa; Godfrey, Timian (The University of Arizona., 2020)
      Purpose: The purpose of this doctor of nursing practice project was to increase patient awareness and knowledge of perinatal anxiety and depression through video education. By providing information on the risk factors, signs and symptoms of anxiety and depression, activities to prevent/reduce symptoms, and local resources, the project aimed to encourage women and their families to discuss maternal mental health and seek help if needed. Background: Pregnancy and postpartum increases a women’s vulnerability for developing a mood disorder due to the significant physiological and psychological changes that accompany having a baby. Mood disorders can greatly impact the mothers’ and family’s health if untreated. The societal stigma of mental health and varying practices of mental health assessment and identification results in underreporting. The complexity of perinatal anxiety and depression increases the need for healthcare providers to educate mothers and their families so that they are informed and can take action to gain mental health support. Methods: Clients from a local breastfeeding and postpartum support center were recruited to watch an educational video on perinatal anxiety and depression via an established online Facebook group. Participants watched the video and completed a pre- and post-survey that assessed awareness, knowledge, confidence, and likeability of the video format on an online research project platform. Results: Twelve participants accessed the project site and completed the demographic questionnaire as eight participants completed the pre-survey, video, and post-survey. No statistically significant differences were found, however, increases in agreement responses after the video education intervention were noted on the post-surveys in seven out of the eight participants. Conclusions: The video education was effective in increasing some knowledge of perinatal anxiety and depression and confidence to seek help. Participants reported that the video was interesting and that they preferred this method of education compared to written material. Limitations surrounding the small sample size and impacts of the COVID-19 pandemic are reviewed. Future research should include employing the video education created in this project in different clinical settings to determine its impact on maternal mental health outcomes
    • Utopian Canvas: Visionary Aspects of Early English-American Literature, 1497-1705

      Scruggs, Charles; Aragona, Jared Lane; Kolodny, Annette; Scruggs, Charles; Willard, Tom (The University of Arizona., 2005)
      This dissertation applies the concept of utopia to literature surrounding the English exploration and colonization of America. The term "utopia" refers to both a literary form and to that concept in human consciousness which catalyzes change in physical reality. Authors express utopia in the visionary aspects of their written representations. Visionary representations produce expectations of what the future may hold, and in this way they helped bring European civilization to America. Studying these representations is valuable for historical clarity and because these representations reveal utopia's function in affecting the course of the future.The study of early English-American literature requires terminology that the current reservoir of utopian terminology does not provide. I offer new terminology. This study defines four broad types of utopian vision specifically applicable to the English exploration and colonization of America. Active Complex visions prioritize maximum manipulation of the landscape to accommodate all the needs of a large and diverse population. Active Simple visions center on one staple venture, like sheepherding, to accommodate the needs of a small population. Divine Patent visions prioritize conformity to values inscribed in theistic religious literature. Natural Primitive visions prioritize the elimination of social infrastructure to achieve harmony with nature. These four types of utopian vision correspond to myths of the past that authors projected as hope for an ideal future.The four types of utopian vision appear throughout the narratives collected by Richard Hakluyt. Voyages by explorers like Sir John Hawkins, Sir Humphrey Gilbert, and Sir Walter Raleigh generated representations of America that expressed Active Complex, Active Simple, or Divine Patent visions. These representations also provided imagery that led to Natural Primitive visions of America. Captain John Smith's narratives about Virginia and New England reveal visions of Active Complex utopias. Puritan authors like William Bradford, Edward Winslow, John Winthrop, and Cotton Mather represented New England with Divine Patent visions. All of these utopian representations influenced later authors, including Thomas Jefferson, Hector St. John de Crevecoeur, and Timothy Dwight. They also continue to influence the way we imagine the United States of America today.
    • Utopian Projects and the Troubled Paradise. Grassroots Discourses and Strategies of Change at the Periphery of Fortaleza, Brazil.

      Greenberg, James; Mandache, Luminita-Anda; Austin, Diane; Jerome, Jessica; Bacelar da Silva, Antonio José (The University of Arizona., 2018)
      In Brazil, inequality, segregation, and urban violence go hand in hand. Not surprisingly, Fortaleza, a city situated in Northeastern Brazil, is the world’s second most unequal city and also Brazil’s most violent. This dissertation aims to understand how residents of the poorest area of Fortaleza—Conjunto Palmeiras—respond to these problems. Conjunto Palmeiras is an extremely poor neighborhood and has the highest homicide rates in the city, yet it is also an important site of activism. Therefore, I seek to understand the tensions between poverty and activism present throughout the history of this neighborhood. What does Conjunto Palmeiras tell us about how marginalized people living in a peripheral neighborhood manage to create and develop political imaginaries of change and act upon them? I ask this question with reference to three historical moments between 1970 and 2017 when collective attempts of problem-solving are clearly evident. The first of such episodes is represented by 1970s to late 1990s period, marking the military dictatorship in Brazil, but also one in which a wave of social movements accompanied the democratization process. The second of these moments is represented by the period 2002 to 2016, which in Latin America, in general, marked the Pink Tide, an era of governance by leftist parties, specifically by the Workers' Party (PT) in Brazil. My focus here is on understanding the contradictions embedded in the institutionalization of a once grassroots project—the solidarity economy movement, rooted in liberation theology—into a state-sponsored program. The third moment is the period between 2015 and 2017, characterized by an increase in drug-related violence in Fortaleza, related to the presence of large drug factions (locally called facções). This dissertation emphasizes that the creation of local political imaginaries, upon which activists developed particular strategies, has been constantly shaped by activists' personal life experiences and interaction with both liberation theology and PT leaders. Shifting understandings of the political landscape reshaped perceptions of poverty and ways to tackle it at the local level. In Brazil, the 13 years of the PT governance put in place a set of socio-economic programs that enabled social mobility for the country's historically marginalized groups. However, during this period, the discourses of older social movements that promoted an egalitarian ideology and a working-class consciousness were replaced with more neoliberal and individualistic understandings of poverty. According to this view, poverty is the result of economic marginalization and can be eradicated by “inclusion” in the market. Yet, over the years, the consciousness-raising process necessary to the formation of a working-class consciousness developed by the liberation theology movement, contributed to the creation of a certain political imaginary among former movement members that inspires the strategies of some local activists. For example, with the increase of homicide rates in Fortaleza, drug related violence emerged in places like Conjunto Palmeiras as a generator of new forms of resistance, where activists dare to challenge the presence and authority of drug gangs through symbolic practices. This phenomenon of change challenges current trends in “resistance” studies to romanticize social movements and portray local leaders as heroes since it situates such forms of activism into larger historical processes of change, which can only be understood in close relation to most activists’ daily experiences with poverty.
    • Utopias of Thought, Dystopias of Space: Science Fiction in Contemporary Peninsular Narrative

      Compitello, Malcolm A.; Divine, Susan Marie; Compitello, Malcolm A.; Williamsen, Amy R.; Szumilak, Monika (The University of Arizona., 2009)
      This study serves as an introduction to three recent narratives in Spanish Science Fiction. While this literary genre has long been read in Spain in translation, it is only recently that Sci-Fi has been successful as a popular literature produced by native authors. Álex de la Iglesia, Gabriela Bustelo and Rafael Reig have worked in realist and genre fiction through their careers but chose to use Science Fiction to speak of the rapidly changing space of Madrid. Their criticism is centered on the changes to the physical, social, economic and political landscape of Madrid post-1992. My analysis is based on the works of the geographer David Harvey, among others, which helps to underline the importance of the urbanization of capital and consciousness that the three narratives disentangle. While being three very different texts - one film and two novels -, they all manipulate concerns of time and space to come to a similar conclusion. Their narratives serve as a warning about how the good intentions of humanist theories like feminism or scientific advancement can easily turn into a nightmare by instead serving the needs of capitalism rather than those of social justice.
    • UTS: A type system for facilitating data communication.

      Schlichting, Richard D.; Hayes, Roger Leonard; Andrews, Gregory R.; Hudson, Scott E.; Yakowitz, Sidney J. (The University of Arizona., 1989)
      This dissertation presents a type scheme called UTS. The goal of UTS is to support composition between autonomous systems and programs. Composition is defined to include procedure call and message passing; it also includes command invocation and the use of stored data. The design of UTS and the principles that guided that design are discussed. The UTS type system is intended as an easily-ported pidgin language. It includes the most common scalar types, such as integer, floating point, and string; the common type constructors such as record and array; and it supports a mechanism for reference to procedures. An innovation of the type scheme is that every value, including procedure values, is tagged with a type indicator, so that it is self-describing. In order to provide a high degree of portability, to provide access to a wide variety of systems, and to support dynamic binding, UTS requires a minimum of centralized knowledge and shared data definitions. It does provide a mechanism for underspecification of types that supports flexible commands and generic procedures. UTS was originally developed as the type system for the Saguaro distributed operating system. UTS is used in Saguaro for all stored data and for procedure invocation both at the system call level and the user interface level. UTS is also used as the type system for MLP, a system that provides heterogeneous remote procedure calls. MLP is designed to minimize the cost of adding new languages while providing the ability to handle common situations easily and automatically. More complex situations can be handled by making use of routines for programmer-controlled inspection and translation of UTS values. Two implementations of MLP are described, with the changes between the versions and the rationale for those changes. The run-time systems for the two versions are also described. The use of MLP is illustrated by projects built on an MLP platform. The largest of these is a prototype of the Saguaro command interpreter. Another is an interface between MLP and the Emerald programming language. The dissertation ends with a summary and discussion of possibilities for future research.
    • UV imaging of extensive air showers at TeV energies.

      Chantell, Mark Charles.; Hsieh, K. C.; Bowen, Theodore; Melia, F.; Shupe, M.A. (The University of Arizona., 1995)
      This work represents the first successful detection of a flux of cosmic gamma rays at TeV energies by an air-Cherenkov imaging telescope from observations made during periods of bright moon light. The detection is based on two years of observations made on the Crab Nebula, a known source of TeV gamma rays, during periods of bright moon light using the Whipple Observatory's 10-meter imaging air Cherenkov telescope outfitted with a camera with spectral sensitivity restricted to UV wavelengths (below 300nm) in place of the conventional visible light sensitive camera. A UV-sensitive camera is obtained by using solar-blind photomultiplier tubes and a UV filter in place of the visible light sensitive photomultiplier tubes in the Whipple camera. The observations result in a detection of a gamma-ray flux from the Crab Nebula at a statistical significance of 5.4 sigma. The performance of this UV-sensitive camera is discussed with particular emphasis on the effects of operating in a bright moonlit environment. The observed signal is shown to behave in a manner which is consistent with what is expected from a gamma-ray flux. Using Monte Carlo simulations, the energy threshold of the camera is estimated to be 0.9TeV and the integral flux derived from this detection is found to be in good agreement with other measurements. Using the experience gained from working with the UV images a second approach to observing in the presence of the moon is tested utilizing the visible sensitive photomultiplier tubes from the conventional Whipple camera with a UV filter to attenuate, but not eliminate, light above 300nm. With this hybrid camera a flux of gamma rays from the Crab Nebula is detected at the 5 sigma level at an estimated energy threshold of 0.7TeV. These two detection's of the Crab Nebula establish the feasibility of utilizing the air-Cherenkov imaging technique during periods of bright moon light, a new capability that would increase the duty cycle of observation.
    • UV-visible and infrared spectroscopy of carbon cluster molecules in solid argon.

      Huffman, D.; Kurtz, Joe.; Garcia, J.D; Thews, R.L.; Wing, W.; Vuillenin, J. (The University of Arizona., 1989)
      The UV-visible absorption spectrum of carbon vapor trapped in solid argon at low temperature contains many intense features, but only those of C₂ and C₃ have been identified. For this work, graphite vapor was produced under high vacuum conditions and condensed with argon onto a cold (∼10K) substrate. The resulting matrix-isolated carbon molecules were analyzed with both UV-visible and infrared absorption spectroscopy. Slight warming of the sample allowed formation of larger molecules and subsequent spectra traced the growth of their absorption features. The experiment associated infrared features to particular UV-visible features via their growth curves. The most reliable correlations are listed below. Theoretical calculations of equilibrium geometries and IR vibrational frequencies were performed on linear and nearly linear carbon chain molecules from C₃ to C₉ at the HF/SCF level of theory and from C₃ to C₇ at the MP2 level of theory, both using the 6-31G* basis set. Tentative assignment of the UV-visible features to molecules was made based on these considerations and on the following: the experimental IR/UV-visible correlations, previous experimental IR work, and modeling of the growth of the UV-visible features during matrix annealing. (UNFORMATTED TABLE FOLLOWS:) Molecule, UV-visible Feature (Å), IR Feature (cm⁻¹), Correlation Coefficient. C₃ (linear), 4100, 2040, .98. C₈ (linear), 3075, 1998, .97. C₈ (cyclic), 3900, 1804, .90. C₆ (linear), 2465, 1952, .86. C₇, 3480. C₉, 4480.
    • Vagueness and Borderline Cases

      Horgan, Terry; Lavine, Shaughan; Daly, Helen; Sartorio, Carolina (The University of Arizona., 2011)
      Vagueness is ubiquitous in natural language. It seems incompatible with classical, bivalent logic, which tells us that every statement is either true or false, and none is vaguely true. Yet we do manage to reason using vague natural language. In fact, the majority of our day-to-day reasoning involves vague terms and concepts. There is a puzzle here: how do we perform this remarkable feat of reasoning? I argue that vagueness is a kind of semantic indecision. In short, that means we cannot say exactly who is bald and who is not because we have never decided the precise meaning of the word 'bald'--there are some borderline cases in the middle, which might be bald or might not. That is a popular general strategy for addressing vagueness. Those who use it, however, do not often say what they mean by 'borderline case'. It is most frequently used in a loose way to refer to in-between items: those people who are neither clearly bald nor clearly not bald. But under that loose description, the notion of borderline cases is ambiguous, and some of its possible meanings create serious problems for semantic theories of vagueness.Here, I clarify the notion of a borderline case, so that borderline cases can be used profitably as a key element in a successful theory of vagueness. After carefully developing my account of borderline cases, I demonstrate its usefulness by proposing a theory of vagueness based upon it. My theory, vagueness as permission, explains how classical logic can be used to model even vague natural language.
    • Valid-time indeterminacy.

      Dyreson, Curtis Elliott.; Snodgrass, Richard T.; Downey, Peter J.; Peterson, Larry (The University of Arizona., 1994)
      In valid-time indeterminacy, it is known that an event stored in a temporal database did in fact occur, but it is not known exactly when the event occurred. We extend a tuple-timestamped temporal data model to support valid-time indeterminacy and outline its implementation. This work is novel in that previous research, although quite extensive, has not studied this particular kind of incomplete information. To model the occurrence time of an event, we introduce a new data type called an indeterminate instant. Our thesis is that by representing an indeterminate instant with a set of contiguous chronons and a probability distribution over that set, it is possible to characterize a large number of (possibly weighted) alternatives, to devise intuitive query language constructs, including schema specification, temporal constants, temporal predicates and constructors, and aggregates, and to implement these constructs efficiently. We extend the TQuel and TSQL2 query languages with constructs to retrieve information in the presence of indeterminacy. Although the extended data model and query language provide needed modeling capabilities, these extensions appear to carry a significant execution cost. The cost of support for indeterminacy is empirically measured, and is shown to be modest. We then show how indeterminacy can provide a much richer modeling of granularity and now. Granularity is the unit of measure of a temporal datum (e.g., days, months, weeks). Indeterminacy and granularity are two sides of the same coin insofar as a time at a given granularity is indeterminate at all finer granularities. Now is a distinguished temporal value. We describe a new kind of instant, a now-relative indeterminate instant, which has the same storage requirements as other instants, but can be used to model situations such as that an employee is currently employed but will not work beyond the year 1995. In summary, support for indeterminacy dramatically increases the modeling capabilities of a temporal database without adversely impacting performance.
    • Validating a Neonatal Risk Index to Predict Necrotizing Enterocolitis

      Effken, Judith A.; Gephart, Sheila Maria; Reed, Pamela G.; Jones, Elaine G.; Halpern, Melissa D.; Effken, Judith A. (The University of Arizona., 2012)
      Necrotizing enterocolitis (NEC) is a costly and deadly disease in neonates. Composite risk for NEC is poorly understood and consensus has not been established on the relevance of risk factors. This two-phase study attempted to validate and test a neonatal NEC risk index, GutCheck(NEC). Phase I used an E-Delphi methodology in which experts (n=35) rated the relevance of 64 potential NEC risk factors. Items were retained if they achieved predefined levels of expert consensus or stability. After three rounds, 43 items were retained (CVI=.77). Qualitative analysis revealed two broad themes: individual characteristics of vulnerability and the impact of contextual variation within the NICU on NEC risk. In Phase II, the predictive validity of GutCheck(NEC) was evaluated using a sample from the Pediatrix BabySteps Clinical Data Warehouse (CDW). The sample included infants born<1500 grams, before 36 weeks, and without congenital anomalies or spontaneous intestinal perforation (N=58,818, of which n=35,005 for empiric derivation and n=23,813 for empiric validation). Backward stepwise likelihood-ratio method regression was used to reduce the number of predictive factors in GutCheck(NEC) to 11 and derive empiric weights. Items in the final GutCheck(NEC) were gestational age, history of a transfusion, NICU-specific NEC risk, late onset sepsis, multiple infections, hypotension treated with Inotropic medications, Black or Hispanic race, outborn status, metabolic acidosis, human milk feeding on both day 7 and day 14 (reduces risk) and probiotics (reduces risk).Discrimination was fair in the case-control sample (AUC=.67, 95% CI .61-.73) but better in the validation set (AUC=.76, 95% CI .75-.78) and best for surgical NEC (AUC=.84, 95% CI .82-.84) and infants who died from NEC (AUC=.83, 95% CI .81-.85). A GutCheck(NEC) score of 33 (range 0-58) yielded a sensitivity of .78 and a specificity of .74 in the validation set. Intra-individual reliability was acceptable (ICC (19) =.97, p<.001). Future research is needed to repeat this procedure in infants between 1500 and 2500 grams, complete psychometric testing, and explore unit variation in NEC rates using a comprehensive approach.
    • Validating and Testing A Model to Predict Adoption of Electronic Personal Health Record Systems in the Self-Management of Chronic Illness in the Older Adult

      Effken, Judith A.; Logue, Melanie D.; Reed, Pamela G.; Murdaugh, Carolyn (The University of Arizona., 2011)
      Problem statement: As a result of the aging population, the number of people living with chronic disease has increased to almost 50% (CDC, 2004). Two of the main goals in treating patients with chronic diseases are to provide seamless care from setting to setting and prevent disability in the older adult. Many have proposed the use of electronic personal health record systems (PHRs) in the self-management process, but adoption remains low. The purpose of this research was to validate and test an explanatory model of the barriers and facilitators to older adults' adoption of personal health records for self-managing chronic illnesses. The long range goal of the research is to use the explanatory model to develop interventions that will maximize the facilitators and minimize the barriers to adoption. Methods: A preliminary attempt to capture the essential barriers and facilitators that predict adoption of PHRs among older adults with chronic illness was synthesized from the literature. In Phase One of the study, the model was integrated from existing literature and validated using a Delphi method. In Phase Two of the study, the model was pilot tested and refined for future investigations. Findings: The results of this study validated the Personal Health Records Adoption Model (PHRAM) and a preliminary instrument that measured barriers and facilitators to the adoption of PHRs in older adults who are self managing chronic illness. Additional findings indicate that while seniors are seeking options to manage their health and have expressed an interest in using Internet-based PHRs, they may require assistance to gain access to PHRs. Implications: The potential for PHRs to increase patient autonomy and reduce for disability and the resulting negative health consequences needs further investigation as we move into the next era of healthcare delivery. The results of this study provided the foundation for continued theoretically-based research in this area.

      Bergan, John R.; Lane, Suzanne; Bergan, John R.; Sabers, Darrell; Nicholson, Glen; Mishra, Shitala P. (The University of Arizona., 1986)
      The present study was a systematic investigation of hierarchical skill sequences in the beginning reading domain. The hierarchies included skills from the traditional approach to reading which reflect bottom-up processing and skills from the conceptual area of print awareness which reflect top-down processing. Researchers supporting the bottom-up approach view reading as a process in which the child extracts information from the text to gain knowledge of the print. The bottom-up processes examined were in the areas of letter recognition and letter naming, and identification of letter sounds and phonemes. The top-down processing approach views reading as a task in which the child brings his/her past experiences and knowledge about the world to gain information about print. The top-down processes examined were in the areas of print identification, inferring a word in context, and print directionality rules. Hierarchical skill sequences were developed within each of the specific areas reflecting the top-down and bottom-up processing theories. Items were developed to reflect the skill sequences based on the cognitive processes that are necessary for correct performance. This involved varying the task demands imposing various requirements of cognitive processing. The data were from 13,189 Head Start children ranging from 3 to 6 years of age. Latent trait models were constructed to reflect the viii ix hypothesized skill sequences by allowing the aj (discrimination) and bj (difficulty) parameters to be free to vary or by constraining them to be equal to other parameters. To arrive at a preferred model, each latent trait model that represented a hypothesized skill sequence was statistically compared against alternative latent trait models. The results from the present investigation supported the hierarchical skill sequences reflecting skills within the traditional area of reading. However, some of the skill sequences from the conceptual area of print awareness were not clearly supported. While the results provide a deeper understanding of beginning reading skill sequences reflecting top-down and bottom-up processing theories, future research is needed to delineate the specific skills which promote later reading ability once the child is in formal reading instruction.
    • Validating cognitive skill sequences in the early social development domain using path-referenced technology and latent trait models.

      Bergan, John R.; Feld, Jason Kane.; Morris, Richard J.; Mishra, Shitala P. (The University of Arizona., 1988)
      The present study was a systematic investigation of hierarchical skill sequences in the early social development domain. Recent research has suggested that social development may be conceptualized as a phenomena involving a hierarchical sequencing of competencies. In particular, social development may involve sequential changes in capability, reflecting successively higher levels of functioning within these competencies. The conceptual problem of this study focused on the construction and validation of a meaningful representation of ability in early social development. Ability was conceptualized as a composite of cognitive procedures governing the performance of specific tasks. The process for constructing skill sequences to reflect ability involved identifying task characteristics or demands which imposed various requirements on cognitive functioning. Hierarchical skill sequences were constructed to tap a variety of capabilities within the early social development domain. These skill sequences included understanding emotions, identifying and mediating needs, understanding friendships, and understanding fairness in decision making. Assessment items were developed to reflect each of these skill sequences based on the cognitive processes that are necessary for correct performance. This involved varying the task demands imposing various requirements on cognitive processing. The data were from 18,305 Head Start children ranging from 30 to 83 months of age. Latent trait models were constructed to reflect the hypothesized skill sequences by allowing the discrimination and difficulty parameters to be free to vary or by constraining them to be equal to other parameters. To arrive at a preferred model, each latent trait model was statistically compared against alternative latent trait models. In general, the results from the present investigation supported the hypothesis that the acquisition of social skills is a developmental phenomena involving a hierarchical sequencing of competencies. Moreover, the study supports the assumption that changes in capability can be defined by progress toward abstraction, complexity, stability, and the handling of increasing quantities of information. While the results provide a deeper understanding of early social development, future research is needed to extend the developmental structure to higher levels of ability. Moreover, research is needed to determine how the information gleaned from developmental assessment can be utilized in planning learning experiences to enhance development.
    • Validating hierarchical sequences in the design copying domain using latent trait models.

      Bergan, John R.; Burch, Melissa Price.; Mishra, Shitala P.; Obrzut, John E. (The University of Arizona., 1988)
      The present study was a systematic investigation of hierarchical skill sequences in the design copying domain. The factors associated with possible variations in task difficulty were delineated. Five hierarchies were developed to reflect variations in rule usage, the structuring of responses, presence of angles, spatial orientations, and stimulus complexity. Three-hundred thirty four subjects aged five through ten years were administered a 25 item design copying test. The data were analyzed using probabilistic models. Latent trait models were developed to test the hypothesized skill sequences. Each latent trait model was statistically compared to alternate models to arrive at a preferred model that would adequately represent the data. Results suggested that items with predictable difficulty levels can be developed in this domain based on an analysis of stimulus dimensions and the use of rules for task completion. The inclusion of visual cues to guide design copying assists accurate task completion. Implications of the current findings for facilitating the construction of tests which accurately provide information about children's skill levels were discussed. The presence of hierarchical skill sequences in a variety of ability domains was supported.
    • Validating the development of male and female preschoolers' help-seeking, goal-setting and planning, and self-evaluation using latent trait models.

      Reddy, Linda Ann.; Bergan, John R.; Mishra, Shitala P.; Feld, Jason K. (The University of Arizona., 1994)
      The present study investigated the early development of three self-regulated learning strategies--help seeking, goal setting and planning, and self evaluation for male and female preschoolers. Skill sequences were developed by identifying demand attributes that imposed requirements on cognitive functioning. The demand attributes of adult assistance and task complexity were identified for all three learning strategies. Variations in adult assistance and task complexity were examined to determine the relative difficulty for male and female preschoolers to perform skills within each learning strategy. This study included data from 10,291 preschoolers, age 2 to 6 years, from Head Start and public preschool programs across the country. The sample included approximately 5,000 males and 5,000 females from culturally diverse backgrounds. Children were assessed by their preschool teachers over two months with a standardized observational assessment instrument. A variety of latent trait models were used to test the developmental skill sequences of these learning strategies in relation to gender. Results revealed that variations in adult assistance and task complexity were related to the relative difficulty in performing these learning strategies. These findings support the notion that adult assistance can enhance the development of preschooler's self-regulated learning strategies. In particular, adult assistance promotes preschoolers' skills to perform simple functions independently and complex functions (e.g., advance planning or checking in parts) with adult help. Gender differences were found in preschoolers' difficulties in self-evaluating and seeking help. For example, females had more difficulty than males checking completed work with adult help and checking an activity in parts with adult help. Males had less difficulty checking a completed activity independently than females. Results also suggested that males are more sensitive to the presence of adult assistance when performing complex checking (i.e., checking in parts) than females. In addition, females were found to be more skilled than males in seeking assistance from adults in the classroom. No gender differences were found in goal setting and planning. The results from this study support the importance of social influences on preschoolers' development of self-regulated learning strategies. Future research directions and implications were also addressed.