Browsing by Subject "decision-making"
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Item An Environmental Perspective to Decision-making for the Control of Johne's Disease on Beef Ranches(2010-10-12) Benjamin, Lisa A.Biosecurity practices for Mycobacterium avium subsp. paratuberculosis (Mptb), the etiologic agent for Johne's disease (JD), are predicated on the fact that fecal-oral is the major route of infection and that Mptb is present in the environment of affected farms. The objectives of these studies were to describe perceived benefits of testnegative Level 4 status in the Voluntary Bovine Johne's Disease Control Program (VBJDCP), describe producer and veterinarian attitudes towards JD relevant biosecurity practices, compare 5 JD control options using a Markov model, determine if tangential flow filtration (TFF) increases the detection sensitivity for Mptb and describe the distribution of environmental predictors for Mptb survival. Twenty-five percent and 39% of beef producers in the VBJDCP reported that they received substantial or marginal benefits (financial and non-financial), respectively, from program participation. Producers suggested increased marketing opportunities to improve the VBJDCP. Producers in a cross-sectional mailed survey of attitudes towards biosecurity practices were more likely than veterinarians to agree that separating JD clinical or suspects from calves or heifers; acquiring replacements or additions from JD low-risk herds, testing for JD every 10 to 14 months and test and culling clinical suspects only were useful for control of JD. A state transition Markov model, with the environment as the source of Mptb, was used to compare 6 alternative control strategies for JD. Management and the probability of Mptb surviving 1 year in the environment were important determinants of the prevalence of subclinical JD on beef farms under the analyzed control strategies. Heterogenous distribution of environmental predictors for Mptb survival was observed in spatial risk maps. In conclusion, although some beef producers experienced gains from participation in the VBJDCP, the perceived program benefits could be improved by increased marketing and education on the advantages of participation. Specific problem areas should be addressed. The length of time Mptb survived in the environment was an important parameter in the Markov chain model. Additionally, due to the heterogenous distribution of environmental predictors, a multiscale approach to sampling and analysis should be useful.Item D2 Dopamine Receptor Mediation of Risky Decision-making(2011-08-08) Simon, Nicholas WayneExcessive risk-taking is a characteristic of several psychopathological disorders. In order to alleviate maladaptive risky behavior, a thorough understanding of the neurobiological and pharmacological substrates of risky choice must be developed. In this dissertation, the ?risky decision-making task? was utilized to explore the mechanisms by which dopamine mediates risky choice. In experiment 1, we characterized rats in risky decision-making as well as a variety of other behavioral traits. This was performed to determine if the behavioral patterns obtained in the risky decision-making task represent an independent cognitive construct rather than a function of a separate behavioral trait. Risky decision-making performance was not correlated with measures of motivation, anxiety, pain tolerance, or other types of decision-making. In contrast, risky choice was correlated with impulsive action as assessed by the Differential Rates of Low Responding Task, suggesting that risky choice may be mechanistically similar to impulsive action. In experiment 2, the effects of various dopaminergic drugs on risky decision-making was investigated. Amphetamine administration attenuated risky choice, while the dopamine antagonist ?-flupenthixol had no effect on risky choice. Agonists and antagonists specific to D1 dopamine receptors had no effects on risky choice; however, the D2 dopamine receptor agonist bromocriptine reduced risky choice in a manner similar to amphetamine. Furthermore, coadministration of amphetamine with a D2 antagonist abolished amphetamine?s effects on risky choice, and amphetamine?s effects were unaffected by coadministration of a D1 antagonist. These data suggest that D2 signaling at the receptor is particularly critical to risky decision-making behavior. In experiment 3, D2 dopamine receptor mRNA abundance was assessed in rats that had been previously characterized in risky decision-making using in situ hybridization. Levels of D2 cRNA hybridization in both orbitofrontal cortex (OFC) and medial prefrontal cortex (mPFC) predicted risky decision-making behavior as assessed by nonlinear curve estimation analyses. Interestingly, opposite relationships between D2 mRNA abundance and risky choice were observed in these two cortical areas, with OFC D2 mRNA abundance showing a U-shaped relationship with risky choice, and mPFC D2 mRNA resembling an inverted U-curve. Additionally, increased levels of D2 mRNA in dorsal striatum were observed in risk-averse rats in comparison to risk-taking rats. In conclusion, these data suggest that signaling via D2 dopamine receptors is an important mediator of risky decision-making behavior, and that D2 signaling in frontostriatal circuitry may be particularly relevant toward these behaviors.Item Decision Motivations: Factors Guiding the Choices of Agriculturalists in California(2014-10-16) Robel, PamelaThis study sought to highlight a specific area of California-agriculturalist behavior?decision-making?that may lend additional insight into how to begin bridging the communication gap between farmers and consumers. Communication between farmers in the United States and the general public is the overarching guidance for this mixed methods (QUAL ? quan) study. Formations of organizations like the U.S. Farmers and Ranchers Alliance have begun to address the communication gap between agriculturalists and consumers through outreach. The results of this study were limited to the study participants as the total response rate for the quantitative portion of the study was 21% (total response was 65 out of 300; useable responses n = 30). The study began with a series of qualitative interviews. The data from the qualitative interviews with California-based agriculturalists were analyzed to guide the creation of a survey instrument. The subsequent survey instrument was distributed to other California-based farmers requesting they rank a series of decision-making factors as they related to annual crop production. Based upon the data collected, the decision-making factors identified in the qualitative strand of the study?water availability, soil quality, market, regulations, and labor?are more widely considered by farmers in California. Additional study is needed to further explore what other factors may guide annual planting decisions for agriculturalists in the state and country.Item Developing an alternative model for travel decision-making(2009-05-15) Hung, KamThis study proposes an alternative travel decision making model and situates its arguments in the Motivation-Opportunity-Ability (MOA) theoretical construct. The MOA model suggests that motivation, opportunity, and ability are major factors influencing decision making. Applying this model in the context of tourism, the proposed model suggests that travel behaviors are determined by self-congruity, functional congruity, perceived travel constraints, constraint negotiation, and self-efficacy. The proposed model and hypotheses were tested in the context of cruise travel. Both qualitative and quantitative methodologies were utilized in this study. Semi-structured interviews with both cruisers and non-cruisers were first conducted to derive measurement items for the interested constructs and to understand how different factors influence travel decision making. An online panel survey was followed to collect quantitative data for testing the proposed theoretical model and hypotheses. Structural Equation Modeling (SEM) was used to test both the proposed model and hypothesized relationships among the constructs. The analyses were performed with Analysis of MOment Structures (AMOS 7.0). All hypotheses except one were supported by the data. The proposed model also had an acceptable fit to the data. Based on the findings, both theoretical and practical implications of the study were recommended.Item Integrated Simulation and Optimization for Decision-Making under Uncertainty with Application to Healthcare(2014-11-26) Alvarado, MichelleMany real applications require decision-making under uncertainty. These decisions occur at discrete points in time, influence future decisions, and have uncertainties that evolve over time. Mean-risk stochastic integer programming (SIP) is one optimization tool for decision problems involving uncertainty. However, it may be challenging to develop a closed-form objective for some problems. Consequently, simulation of the system performance under a combination of conditions becomes necessary. Discrete event system specification (DEVS) is a useful tool for simulation and evaluation, but simulation models do not naturally include a decision-making component. This dissertation develops a novel approach whereby simulation and optimization models interact and exchange information leading to solutions that adapt to changes in system data. The integrated simulation and optimization approach was applied to the scheduling of chemotherapy appointments in an outpatient oncology clinic. First, a simulation of oncology clinic operations, DEVS-CHEMO, was developed to evaluate system performance from the patient and managements perspectives. Four scheduling algorithms were developed for DEVS-CHEMO. Computational results showed that assigning patients to both chairs and nurses improved system performance by reducing appointment duration by 3%, reducing waiting time by 34%, and reducing nurse overtime by 4%. Second, a set of mean-risk SIP models, SIP-CHEMO, was developed to determine the start date and resource assignments for each new patients appointment schedule. SIP-CHEMO considers uncertainty in appointment duration, acuity levels, and resource availability. The SIP-CHEMO models utilize the expected excess and absolute semideviation mean-risk measures. The SIP-CHEMO models increased throughput by 1%, decreased waiting time by 41%, and decreased nurse overtime by 25% when compared to DEVS-CHEMOs scheduling algorithms. Finally, a new framework integrating DEVS and SIP, DEVS-SIP, was developed. The DEVS-CHEMO and SIP-CHEMO models were combined using the DEVS-SIP framework to create DEVS-SIP-CHEMO. Appointment schedules were determined using SIP-CHEMO and implemented in DEVS-CHEMO. If the system performance failed to meet predetermined stopping criteria, DEVS-CHEMO revised SIP-CHEMO and determined a new appointment schedule. Computational results showed that DEVS-SIP-CHEMO is preferred to using simulation or optimization alone. DEVSSIP-CHEMO held throughput within 1% and improved nurse overtime by 90% and waiting time by 36% when compared to SIP-CHEMO alone.Item Perception of genetic risk in sexual and reproductive decision-making (PGRID) by college students(2009-05-15) Honore?, Heather HelaineOne psychosocial variable, human mate selection, has been studied extensively within the field of evolutionary psychology. A question of interest is how sexual/reproductive decision-making (i.e., dating, marrying, and childbearing) might be influenced by an individual?s perception of his/her genetic risk and other psychosocial variables. There is a paucity of empirical studies within the literature exploring this specific relationship. This partially mixed, sequential mixed methods study addresses how individual perception of genetic risk (PGR) influences or predicts sexual/reproductive intentions and decision-making. A systematic review of the literature was conducted by searching for English language, peer-reviewed, empirical studies in Cambridge Scientific Abstracts databases (N=26). Next, students from three Southwestern universities were recruited for focus groups and responded to 15 open-ended questions (N=86). Transcripts were audiotaped, transcribed verbatim and analyzed using holistic-content analysis. Based on the literature review and qualitative findings, a 138-item, web-based instrument was designed and tested at two Southwestern universities (N=2,576). Survey data were analyzed using non-parametric univariate analyses and multiple regression. Approximately 50 demographic, individual/familial psychosocial and genetic testing-related factors influenced the relationship between PGR and sexual/reproductive decision-making in reviewed studies. Individual psychosocial factors (e.g., intention, attitudes) represented 65.8% of all findings. Participants in the qualitative phase exhibited moderate health literacy when interpreting and discussing genetic risk information. A number of factors including age, gender, religion, individual/family values, and exposure to genetic concepts/technology appeared to influence sexual/reproductive decision-making. Demographic, Health Belief Model (HBM) and Theory of Planned Behavior (TPB) variables predicted the relationship between PGR and dating, marital, and childbearing intention in the quantitative phase. TPB variables were the strongest predictors of intention accounting for 33.1-38.7% of variance. Positive family norms were the single best predictor of dating and marital intention. Age was the best predictor of childbearing intention. Further research is needed to understand how young adults incorporate genetic risk perceptions into sexual/reproductive decision-making. Mixed methods and longitudinal study designs, and structural equation modeling are recommended for use in future studies. Study findings affirm a need for health educators to consider adopting genomic competencies; creating theory-based curricula/interventions; and forming partnerships with genetic specialists and local/regional health departments.Item Politically rational foreign policy decision-making(Texas A&M University, 2006-10-30) Kent, Charles ToddThis dissertation is an analysis of how presidents make foreign policy decisions. Rather than explaining foreign policy decisions by focusing on individuals or institutions, I stress the role of political pressures and context faced by presidents. It shows that foreign policy decisions are not merely a reaction to stimulus from the international or domestic arenas but involve political considerations that affect policy choice. The dynamic elements in the argument are political resources and risk. The relationship between the risk propensity of the president and presidential political resources provides an important link to understanding foreign policy decisions. Within the realm of good public policy, a politically rational president can choose to act or respond to foreign policy disputes in various ways, including diplomacy, political coercion, economic coercion, covert action, or military intervention, based on his assessment of the political context and his willingness to accept the associated risks. The level of presidential political resources determines the risk propensity of the president. Presidential foreign policy decisions will vary depending on the quantity of available political resources. Thus, understanding the risk propensity of the president increases our ability to explain foreign policy decisions. The contribution of this research is the identification of a mechanism for understanding how the interaction between the domestic and international political environments, and individual decision-makers influence foreign policy decisions. My research bridges the gap between structural theories, ??????theories that make predictions about foreign policy outcomes without reference to the cognition and actions of the actors themselves,?????? and decision-making theories that stress the role of the actors (Ikenberry 2002, 5). Although the component parts of the foreign policy decisionmaking system are widely known, we lack theories that tie the pieces together.Item Risk identification and assessment in a risk based audit environment: the effects of budget constraints and decision aid use(Texas A&M University, 2006-10-30) Diaz, Michelle ChandlerRisk based audit (RBA) approaches represent a major trend in current audit methodology. The approach is based on risk analysis used to identify business strategy risk. The RBA has created a new set of research issues that need investigation. In particular, this approach has important implications for risk identification and risk assessment. The success of the RBA approach is contingent on understanding what factors improve or interfere with the accuracy of these risk judgments. I examine how budget constraints and decision aid use affect risk identification and risk assessment. Unlike previous budget pressure studies, I cast budget constraints as a positive influence on auditors. I expect more stringent budget constraints to be motivating to the auditor as they provide a goal for the auditor to achieve. I also expect budget constraints to induce feelings of pressure leading to the use of time-pressure adaptation strategies. When auditors have use of a decision aid, they take advantage of these motivational goals and/or use beneficial adaptive strategies. Overall, I find that auditor participants tend to be more accurate when identifying financial statement risks compared to business risks. Budget constraints have no effect on risk identification for financial or business risks; they also have no effect on financial risk assessments. On the other hand, business risk assessments are improved by implementing more stringent budget constraints, but only when a decision aid is also provided. Budget constraints can affect performance through a goal theory route or a time-pressure adaptation route. I investigate the paths through which budget constraints improve business risk assessments under decision aid use. I find that budget constraints directly affect performance, supporting a goal theory route. However, I do not find that budget constraints are mediated by perceived budget pressure as expected. Auditors appear to use a positive adaptive strategy to respond to perceived budget pressure, however perceived budget pressure is not induced by providing a more stringent budget.Item The decision-making modeling for concurrent planning of construction projects(2009-05-15) Shim, EuysupConcurrent construction, in which multiple construction activities are carried out concurrently or overlapping, is a method developed to reduce time-to-market and increase the value of the project to the owner or user. When overlapping activities, the additional cost for overlap is affected by the interaction between overlapped activities which is affected by the construction work methods used. Thus concurrent planning of construction projects can lead to a benefit for the owner through investigating the interactions between work methods under overlap and finding the best degrees of overlap. However, the determination of the best solution from all the possible combinations of multiple methods and degrees of overlap is affected by the decisionmaking approach: by a centralized decision-maker (e.g., the project manager) with less accurate information about cost estimates or by a decentralized decision-maker(s) (e.g., subcontractors) with a myopic viewpoint. The objective of this dissertation is to compare the solutions from the two decision-making approaches and to identify the conditions in which one approach is preferred to the other. Thus project owners can benefit from choosing a better approach for concurrent planning under their own conditions. A Monte Carlo simulation model for each decision-making approach was developed: an algorithm for finding the best solution was developed by heuristic methods. Several parameters were incorporated into the models to reflect different conditions for the decision-making approaches: number of activities, number of methods, the project manager?s solution capacity, the uncertainty in the project manager?s knowledge and attitudes towards risk. The comparison of the two approaches was implemented with random cost under different conditions. Furthermore, the model was applied to a hypothetical construction project. From the simulations the major conclusions include: (1) The decentralized approach becomes preferred with more activities; (2) Considering more methods provides more potential for higher benefit to the owner in the decentralized approach; (3) The decentralized approach is recommended under risk-averse attitude and high uncertainty in the project manager?s knowledge.