Doctor of Philosophy

dissertationWater is arguably the most important resource for successful crop production in the Southwest. In this dissertation, I examine the economic tradeoffs involved in dry farming maize vs. maize farming using simple surface irrigation for the Fremont farmers who occupied Range Creek Canyon, east-central Utah from AD 900 to 1200. To understand the costs and benefits of irrigation in the past, maize farming experiments are conducted. The experiments focus on the differences in edible grain yield as the amount of irrigation water is varied between farm plots. The temperature and precipitation were tracked along with the growth stages of the experimental crop. The weight of experimental harvest increased in each plot as the number of irrigations increased. The benefits of irrigation are clear, higher yields. The modern environmental constraints on farming in the canyon (precipitation, temperature, soils, and amount of arable land) were reconstructed to empirically scale variability in current maize farming productivity along the valley floor based on the results of the experimental crop. The results of farming productivity under modern environmental constraints are compared to the past using a tree-ring sequence to reconstruct water availability during the Fremont occupation of Range Creek Canyon. The reconstruction of past precipitation using tree ring data show that dry farming would have been extremely difficult during the period AD 900-1200 in Range Creek Canyon. Archaeological evidence indicates that the Fremont people were farming during this period suggesting irrigation was used to supplement precipitation shortfalls. Large amounts of contiguous arable land, highly suitable for irrigation farming, are identified along the valley bottom. The distribution of residential sites and associated surface rock alignment features are analyzed to determine whether the Fremont located themselves in close proximity to these areas identified as highly suitable for irrigation farming. Seventy-five percent of the residential sites in Range Creek Canyon are located near the five loci identified as highly suitable for irrigation farming

An Integrated Approach to Teach Communication Skills Using Educational Technologies

The purpose of this pre-experimental pre-test/post-test design was to identify a group of agricultural education students’ knowledge and perceptions towards the use of integrated educational technologies in the classroom. The population was 17 agricultural education students enrolled in an agricultural communications course over a two-year period. A multimedia content development touch screen resource was integrated into the course as a capstone project. Pretest and posttest evaluations showed 6% to 57% changes in knowledge as a result of the digital capstone project. The most significant changes were seen in storyboarding, multimedia project development, and graphic design principles, indicating that students require additional education in these areas. The lowest percentage changes were seen in the same three competencies each year; revealing that students were most knowledgeable in interviewing, technical writing, and giving public presentations. The findings revealed that students gained the most knowledge in technology development, integration and application, rather than interpersonal skill building. This integrated course provides an example of how educators can design courses that not only increase students’ communications knowledge and skills, but also gain realistic experience by creating their own multimedia content for public communication

Student Expectations and Reflections of a Study Away Course Experience to Washington, D.C.

Active, out-of-the-class learning experiences have proven to provide students with a variety of benefits. One way to offer these valuable experiential education opportunities this is through study away to international or domestic destinations. The purpose of this study was to explore students’ perceptions of a study away course experience to Washington, D.C. This course was a collaborative effort between two universities. Twenty-two students participated in the study away experience and 21 completed pre- and post-trip questionnaires to determine their expectations and reflections of the experience. Through qualitative analysis of students’ open-ended responses, emergent themes were identified. Students expected to gain a new experience, network with others, and have an enjoyable trip. Post-trip reflections revealed students gained a great deal more than they anticipated, both personally and academically. Recommendations for practice and research are provided

Medical-Legal Partnerships to Support Continuity of Care for Immigrants Impacted by HIV: Lessons Learned from California.

The United States (US) has experienced a surge of anti-immigrant policies and rhetoric, raising concerns about the influence on health outcomes for immigrants living in the US. We conducted qualitative interviews (n = 20) with health care and social service providers, attorneys, and legal/policy experts in California to understand how agencies were maintaining access to HIV care and prevention for immigrant clients. We conducted a thematic analysis to describe the role of medical-legal partnerships (MLPs) and document best practices. Informants reported high demand for legal services. Referrals were facilitated by case managers, medical providers, and pre-existing relationships between clinics and legal agencies. Informants identified a need for additional funding and further guidance on screening for and supporting patients with legal needs. MLPs have the capacity to create sustainable, efficient, comprehensive structural changes that minimize barriers to HIV prevention and treatment and improve health outcomes among immigrant populations

Legislative Perceptions of Sustainable Tourism : The Case of the North Carolina General Assembly

The tourism industry is the second largest contributor to North Carolina's economy. The traditional thrust behind many national and state tourism policies has focused on the industry's employment potential and opportunities for economic growth. However, consumer demand is shifting toward a more sustainable approach to tourism that balances economic growth with environmental and social-cultural enhancement and equity. Given the growing pressure placed on legislators to address tourism development, and specifically sustainable tourism, there is a clear need to better understand legislators' perceptions of tourism and enhance communication between legislators and tourism practitioners.   By identifying the perceptions of elected leaders at the state level; destination marketers, advocates of sustainability, and consumers will have a better understanding of how to effectively communicate with, and lobby their local legislators. This study replicates and extends a previous study. Using a multi-method approach data were collected through a web-based survey, mail survey, and face-to-face interception; this study seeks to measure and analyze North Carolina legislators' knowledge of and attitudes towards the tourism industry and sustainable development within the industry.  M.S

Using mutual information to measure order in model glass-formers

Whether or not there is growing static order accompanying the dynamical heterogeneity and increasing relaxation times seen in glassy systems is a matter of dispute. An obstacle to resolving this issue is that the order is expected to be amorphous and so not amenable to simple order parameters. We use mutual information to provide a general measurement of order that is sensitive to multi-particle correlations. We apply this to two glass-forming systems (2D binary mixtures of hard disks with different size ratios to give varying amounts of hexatic order) and show that there is little growth of amorphous order in the system without crystalline order. In both cases we measure the dynamical length with a four-point correlation function and find that it increases significantly faster than the static lengths in the system as density is increased. We further show that we can recover the known scaling of the dynamic correlation length in a kinetically constrained model, the 2-TLG.Comment: 10 pages, 12 Figure

Pharmacointeraction Network Models Predict Unknown Drug-Drug Interactions

Drug-drug interactions (DDIs) can lead to serious and potentially lethal adverse events. In recent years, several drugs have been withdrawn from the market due to interaction-related adverse events (AEs). Current methods for detecting DDIs rely on the accumulation of sufficient clinical evidence in the post-market stage – a lengthy process that often takes years, during which time numerous patients may suffer from the adverse effects of the DDI. Detection methods are further hindered by the extremely large combinatoric space of possible drug-drug-AE combinations. There is therefore a practical need for predictive tools that can identify potential DDIs years in advance, enabling drug safety professionals to better prioritize their limited investigative resources and take appropriate regulatory action. To meet this need, we describe Predictive Pharmacointeraction Networks (PPINs) – a novel approach that predicts unknown DDIs by exploiting the network structure of all known DDIs, together with other intrinsic and taxonomic properties of drugs and AEs. We constructed an 856-drug DDI network from a 2009 snapshot of a widely-used drug safety database, and used it to develop PPIN models for predicting future DDIs. We compared the DDIs predicted based solely on these 2009 data, with newly reported DDIs that appeared in a 2012 snapshot of the same database. Using a standard multivariate approach to combine predictors, the PPIN model achieved an AUROC (area under the receiver operating characteristic curve) of 0.81 with a sensitivity of 48% given a specificity of 90%. An analysis of DDIs by severity level revealed that the model was most effective for predicting “contraindicated” DDIs (AUROC = 0.92) and less effective for “minor” DDIs (AUROC = 0.63). These results indicate that network based methods can be useful for predicting unknown drug-drug interactions

Uranium(III) coordination chemistry and oxidation in a flexible small-cavity macrocycle

U(III) complexes of the conformationally flexible, small-cavity macrocycle trans-calix[2]benzene[2]pyrrolide (L)2–, [U(L)X] (X = O-2,6-tBu2C6H3, N(SiMe3)2), have been synthesized from [U(L)BH4] and structurally characterized. These complexes show binding of the U(III) center in the bis(arene) pocket of the macrocycle, which flexes to accommodate the increase in the steric bulk of X, resulting in long U–X bonds to the ancillary ligands. Oxidation to the cationic U(IV) complex [U(L)X][B(C6F5)4] (X = BH4) results in ligand rearrangement to bind the smaller, harder cation in the bis(pyrrolide) pocket, in a conformation that has not been previously observed for (L)2–, with X located between the two ligand arene rings

Hospital-Based Physicians\u27 Intubation Decisions and Associated Mental Models when Managing a Critically and Terminally Ill Older Patient.

BACKGROUND: Variation in the intensity of acute care treatment at the end of life is influenced more strongly by hospital and provider characteristics than patient preferences. OBJECTIVE: We sought to describe physicians\u27 mental models (i.e., thought processes) when encountering a simulated critically and terminally ill older patient, and to compare those models based on whether their treatment plan was patient preference-concordant or preference-discordant. METHODS: Seventy-three hospital-based physicians from 3 academic medical centers engaged in a simulated patient encounter and completed a mental model interview while watching the video recording of their encounter. We used an expert model to code the interviews. We then used Kruskal-Wallis tests to compare the weighted mental model themes of physicians who provided preference-concordant treatment with those who provided preference-discordant treatment. RESULTS: Sixty-six (90%) physicians provided preference-concordant treatment and 7 (10%) provided preference-discordant treatment (i.e., they intubated the patient). Physicians who intubated the patient were more likely to emphasize the reversible and emergent nature of the patient situation (z = -2.111, P = 0.035), their own comfort (z = -2.764, P = 0.006), and rarely focused on explicit patient preferences (z = 2.380, P = 0.017). LIMITATIONS: Post-decisional interviewing with audio/video prompting may induce hindsight bias. The expert model has not yet been validated and may not be exhaustive. The small sample size limits generalizability and power. CONCLUSIONS: Hospital-based physicians providing preference-discordant used a different mental model for decision making for a critically and terminally ill simulated case. These differences may offer targets for future interventions to promote preference-concordant care for seriously ill patients

On the functions generated by the general purpose analog computer

PreprintWe consider the General Purpose Analog Computer (GPAC), introduced by Claude Shannon in 1941 as a mathematical model of Differential Analysers, that is to say as a model of continuous-time analog (mechanical, and later one electronic) machines of that time. The GPAC generates as output univariate functions (i.e. functions f:R→R). In this paper we extend this model by: (i) allowing multivariate functions (i.e. functions f:Rn→Rm); (ii) introducing a notion of amount of resources (space) needed to generate a function, which allows the stratification of GPAC generable functions into proper subclasses. We also prove that a wide class of (continuous and discontinuous) functions can be uniformly approximated over their full domain. We prove a few stability properties of this model, mostly stability by arithmetic operations, composition and ODE solving, taking into account the amount of resources needed to perform each operation. We establish that generable functions are always analytic but that they can nonetheless (uniformly) approximate a wide range of nonanalytic functions. Our model and results extend some of the results from [19] to the multidimensional case, allow one to define classes of functions generated by GPACs which take into account bounded resources, and also strengthen the approximation result from [19] over a compact domain to a uniform approximation result over unbounded domains.info:eu-repo/semantics/acceptedVersio