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    Bioengineering Investigations of Pulmonary Vascular Function in Pulmonary Hypertension: In Vivo, In Vitro and Modeling Studies

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    Pulmonary hypertension (PH) is characterized by chronic high blood pressure in the pulmonary arteries (PAs) and is an important cause of morbidity and mortality in children and adults. During the development of PH, the pulmonary circulation displays significant arterial remodeling, which yields changes in mechanical behavior and subsequently, of pulmonary vascular function (PVF). Recent clinical findings suggest that knowing the change in PVF is important for accurate prognosis of PH and its severity, and may be relevant in developing treatment strategies. One clinical effort has focused on the measurement of pulmonary vascular input impedance, which can provide comprehensive characterization of PH and the mechanical properties and behavior of proximal PAs; these properties strongly affect the impedance and right ventricular afterload. In this dissertation, the measurement uncertainty in the pulmonary vascular input impedance estimated from pulsed-wave Doppler-measured velocity and pressure measurements is examined to provide the guidance for the use of impedance in clinical studies. To examine the mechanical properties of proximal PAs, in vitro studies on the arterial remodeling including mechanical and histological aspects due to chronic hypoxia in the proximal PAs of both adult rat and neonatal calf models of PH are performed to seek mechanobiological relation of the proximal PAs. Combining in vitro and in vivo arterial geometry data from main PA (MPA) of neonatal calves, the in vivo stretch distribution and collagen engagement in MPAs are examined and the impact of residual stretch and arterial remodeling is then investigated. Finally, an approach is proposed to quantify the appropriateness of constitutive models for proximal PAs by comparing the predicted and measured pressure-diameter curves in calf MPAs. With the constitutive model, the relation between the collagen contribution to the pressure loading at the physiological conditions and the PH disease state can be established, and such concept can be applied to clinical studies for the diagnosis of PH. Overall, these investigations of PVF in PH from in vivo, in vitro and modeling studies can provide a better understanding of functional changes of the entire pulmonary circulation, which in turn will be useful to the diagnosis and treatment of PH

    Atomic Layer Deposition Enabled Interconnect and Packaging Technologies for As-Grown Nanowire Devices

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    Nanowires (NWs) have attracted considerable interests in many applications due to their small size, extremely high surface-to-volume ratio, and superior material properties. They are promising material candidates as fundamental building blocks for future electronic, optoelectronic, energy, sensor, and biomedical applications. The majority of research activities have focused on the synthesis of NWs. With the advent of high-performance NWs, interconnect and packaging of NWs are becoming increasingly important for device applications. Vertical NW array devices, compared with horizontal NW configurations, are of great importance for achieving ultra-high integration density at the device level without the need of additional assembly and rearrangement processes. Currently, however, it is very challenging to interconnect and package as-grown vertical NWs because of their small sizes and extremely high aspect ratios. This thesis work contributes to the design, fabrication, and characterization of atomic layer deposition (ALD)-enabled interconnect and packaging technologies for as-grown vertical NWs. The first goal of this thesis is to develop a generic interconnect technology that can interconnect and encapsulate as-grown vertical NWs. We have developed a novel interconnect solution by encapsulating as-grown NWs with a nanoscale multilayer consisting of ALD-alumina and tungsten (W) layers for dielectric and electrical interconnects. The electrical connection of ALD-enabled interconnect was verified by the photoluminescence (PL) measurement of NWs. By injecting current into W interconnect along NWs, a dynamic PL tuning experiment was demonstrated, and this experiment verified the connection of W interconnect on NWs. The effect of the matrix layer on PL measurement has been studied and a process has been developed to eliminate such an effect. With local removal of ALD-W at the tips of the NWs, we verified that the PL is measured from the tip of the NWs. By measuring temperature dependence of peak PL wavelength from the tips of the NWs, we are able to predict tip temperature and corresponding thermal performance of as-grown NW devices. With the increase of device integration density and power consumption in electronics and optoelectronics, thermal management is one of the most critical packaging issues. A much higher power density than that in conventional planar devices is expected for as-grown vertical NW devices due to the potentially much high integration density. The second goal of this thesis is thus devoted to developing an effective cooling design and fabrication for as-grown NW devices. Thermal simulation is used to guide the design and fabrication of cooling-enhanced as-grown NW devices. NWs are successfully encapsulated with adjustable-thickness coverage of electroplated copper as effective heat spreading. Thermal simulation predicts a reduction of thermal resistance by 52X for the electroplated copper on as-grown NW devices compared with state-of-the-art polymer encapsulation

    Optimal Control Applications in Space Situational Awareness

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    There are currently more than 19,000 trackable objects in Earth orbit, 1,300 of which are active. With so many objects populating the space object catalog and new objects being added at an ever increasing rate, ensuring continued access to space is quickly becoming a cornerstone of national security policies. Space Situational Awareness (SSA) supports space operations, space flight safety, implementing international treaties and agreements, protecting of space capabilities, and protecting of national interests. With respect to objects in orbit, this entails determining their location, orientation, size, shape, status, purpose, current tasking, and future tasking. For active spacecraft capable of propulsion, the problem of determining these characteristics becomes significantly more difficult. Optimal control techniques can be applied to object correlation, maneuver detection, maneuver/spacecraft characterization, fuel usage estimation, operator priority inference, intercept capability characterization, and fuel-constrained range set determination. A detailed mapping between optimal control applications and SSA object characterization support is reviewed and related literature visited. Each SSA application will be addressed starting from first principles using optimal control techniques. For each application, several examples of potential utility are given and discussed

    Mixing of Dust in Protoplanetary Disks and the Solar Nebula

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    Understanding the small-dust component of protoplanetary disks is key to understanding the conditions for planet formation. Small dust grains, particularly at large distances, provide our primary observational window into the physics of protoplanetary disks, being much more easily observed than the gas component. Furthermore, the distribution of these grains must ultimately control the timing and locations for planetesimal formation, the first major step toward planet formation. For my thesis work, I have used numerical simulations to model the radial distribution of dust grains as they are acted upon by the gas disk, including the evolution of the disk (outward expansion and inward accretion), radial and azimuthal drag of the gas flow on the particle orbits, and turbulent mixing of the particle ensemble radially within the disk. I have run simulations using a range of particle sizes and disk-model parameters and consider primarily two phenomena: the radial diffusion of hot, inner disk particles outward to large AU, relevant to the compositional makeup of bodies within our own solar system, and the time evolution of the global dust-to-gas ratio, which dictates the supply of solid material to the planetesimal- and planet-forming regions. I find that, while the degree out outward mixing depends sensitively on a number of disk-model parameters, the behavior of the global dust-to-gas distribution is relatively uniform between different disk-model simulations, suggesting that, while still mysterious, the conditions for planetesimal formation are commonly met across a range of disk configurations. Observed disk compositions correlate poorly with most observable disk parameters. However, my simulations suggest compositional properties are most-strongly controlled by the initial conditions of young disk systems

    Genetic and Environmental Risk Factors for Disordered Eating and Co-Occurring Traits

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    Prior studies have shown that eating disorders and disordered eating characteristics have similar contributions of genetic and environmental influences. However, few studies have identified specific genetic variants that influence these phenotypes. It is possible that the lack of replication studies is due to the focus on one particular polymorphism rather than a more comprehensive approach that includes multiple polymorphisms at a given locus. In addition, little information is known about common risk factors for eating disorders and co-occurring traits, such as substance use and personality. This dissertation uses adolescent and young adult twins and their family members from the community sample of the Colorado Center for Antisocial Drug Dependence (CADD) to investigate risk factors for disordered eating, substance use, and specific personality traits. Findings from the research examining risk factors for disordered eating provide insight into whether putative genetic variants, such as those in the serotonin transporter gene (SLC6A4), are associated with these characteristics. First, extended twin analyses were used to investigate genetic and environmental influences on two disordered eating characteristics identified from the CADD. Second, a family-based association test examined whether specific genetic variants in and near SLC6A4 were associated with disordered eating. Finally, phenotypic correlations among disordered eating, substance use, and personality traits were examined. Results from the first study suggested that individual differences in disordered eating characteristics could be explained by additive genetic and non-shared environmental influences. Findings from the second study suggested that a genetic variant upstream of the 5\u27 region of SLC6A4 was associated with a measure of weight and shape concerns and behaviors, even after controlling for multiple genetic variant testing. The final study found small phenotypic correlations between disordered eating and multiple substance use measures, and between disordered eating and specific personality traits. Implications for these findings are discussed

    \u22Don’t Ruin My Pretend\u22: Kids Sustaining Play Interactions in Out-of-School Settings

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    As much as play is researched and discussed by people interested in children and childhood, studies often fail to examine closely the ways that kids accomplish their play. This study sought to answer the question of how children sustain their play interactions. By making use of qualitative methods to collect and analyze data, the play of elementary-age children was studied in the summer camp and school recess settings. In these settings, children were less closely supervised by adults and were freer to make their own decisions about their interactions, in comparison to more structured settings such as school classrooms or organized sports. Findings from this study revealed that kids worked to sustain their play interactions by creating a participation framework that included one participant being in charge within each interaction. The kid in charge played the role of the boss and managed the play activity. The other kids followed and took on support roles. In addition, findings revealed that unwritten rules around social interactions were important to the ways kids interacted with each other. Play activities were found to be made up of nuanced communication that was evidence of the work kids did to sustain their interactions. By managing their own play activity, kids worked to sustain interactions without the guidance of adults in the moment

    Policy Agendas and Procedural Avoidance in the Lower Federal Courts

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    This thesis explores tools used by federal lower court judges when deciding cases in the face of divergent political preferences. I show that judges make use of procedural \u22outs,\u22 doctrines to do with judicial power, as a means of dealing with political conflict. This manifests both as a response to collegial conflict, allowing judges to come to agreement on a single opinion, and also as a response to hierarchical conflict, allowing lower court judges to assert power over the policy agendas of higher court judges by limiting issues before the court. Analysis of behavior in appellate panels supports the theory that judges avoid ideological conflict with colleagues by writing procedural decisions instead of reaching the substantive issues in the case. Thus, appellate panels with a wide range of ideological views more often refuse to reach the merits of a dispute than ideologically aligned panels. This avoidance behavior leads to opinions based in procedural law. These findings indicate that procedural law plays an important role in collegial court decision making by allowing judges with conflicting political preferences to resolve disputes in a way that sidesteps conflict. Further, district court judges sitting beneath ideologically \u22hostile\u22 appellate courts are far more likely to render narrow \u22procedural\u22 decisions that sidestep the substantive issues posed by a case than district court judges who are ideologically aligned with the relevant appellate circuit. This behavior has consequences for the availability of issues to higher courts as appellate judges will generally refrain from reaching the merits of a dispute unless the district court has already done so. In sum, then, this thesis provides empirical support for the idea that political conflict may lead to one form of judicial minimalism; however, such conflict may also account for incoherence and inconsistencies in the application of the rules about judicial power. Overall, a goal of this thesis is to begin to explain the complex set of forces that govern the content of opinions rather than maintaining a hard focus on outcomes alone

    Effective Practices for Establishing an Interactive Theatre Program in a University Community

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    How should one go about establishing a viable Interactive Theatre ensemble that can provide quality programming to communities on university campuses? This dissertation infers effective practices for doing so based on a study of Interactive Theatre and a comparative analysis of five representative Interactive Theatre programs in universities across the country: Theatre for Dialogue at the University of Texas at Austin, Cornell Interactive Theatre Ensemble, InterAct at The Ohio State University, the Interactive Theatre Project at the University of Colorado at Boulder, and Interactive Theatre Carolina at the University of North Carolina at Chapel Hill. The data sources are threefold: interviews with ensemble leaders, funders and actors; evaluation data and other documents from the programs; and scholarship both inside and outside the field of Interactive Theatre. Effective practices are defined as those which, according to the three sources of data, have proven to be successful in maximizing the efficacy and impact of the work. The methodology is a form of qualitative social science research called “Case Study,” specifically an “Instrumental Study” and “Collective Case Study.” The study focuses on a broad set of issues and skill sets within Interactive Theatre divided up into four categories as follows: “Program Foundations,” including Genesis Stories, Funding/Sustainability/Growth, Goals, Theory/Influences, Issues, Audiences, Marketing, Space, and Allies/Advocates; “Structure and Methods,” including Services/Format/Techniques, Ensemble Structure, Recruiting/Auditioning, Student Commitment, Academic Courses on Interactive Theatre, Scene/Script Creation, and Rehearsal/Training; “Facilitation,” including Roles and Techniques of the Facilitator, Engagement of Audience Members, Creating a Safe Space, Encouraging Quieter Voices to Speak Up, Managing and Deepening the Conversation, Negotiating Conflict/Dealing with Resistance, Facilitating Social Justice Education, the Role of Identity, Co-facilitation, Hegemony/Master Narratives/Dominant Ideologies; and “Evaluation/Impact,” including Current Evaluation Practices, Evaluation Results, Scholarship on Evaluation, Effective Practices for Evaluation, and the Impact on Student Ensemble Members. Finally, the study draws additional conclusions in the form of ethical, theoretical, and practical implications and outlines the next steps for future and current practitioners. Despite the dissertation’s narrow focus on the university setting, the conclusions can be easily applied to other settings, including high schools and community organizations

    Semi-Automatic Discovery of Meaningful Ontology from a Relational Database

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    Many legacy relational databases are hidden behind business layers containing semantic in- formation describing the data contained within the tables of the database. With the creation of the Semantic Web some databases have been exposed utilizing this technology, but with a cost. The process of exposing the database to the Semantic Web has not taken o_ because the manual mapping of the database to the ontology is improbable at a large scale, it is a time intensive process, and to create a domain ontology requires an Ontologist and/or domain expert. Many applications and approaches have been presented over the years to help expose these legacy databases to the Semantic Web. None of these solutions has become widely accepted because they translate all the data to Resource Description Framework (RDF). This does not work with legacy databases since other systems are still interacting with that data. In addition, systems that translate the data from legacy database to RDF triples do not scale for large databases because a statement or RDF triple is made for every cell within every table. Thus, the amount of information generated from a legacy system that has terabytes of data grows too large to be store in a triple store. Other systems generate an ontology that is a basic representation of the schema and lacking any type of hierarchy or semantic meaning. This thesis proposes an architecture that will semi-automatically extract a meaningful ontology in a timely manner that can scale to handle large database and expose the database as virtual RDF graph by mapping the extracted domain ontology to the database. This will be accomplish by utilizing mapping rules that will evaluate the schema along with the data within the database and utilize existing knowledge base, like DBpedia, in order to find similar ontology classes that match the structure and data within the database. This hybrid approach to ontology extraction and generation of a mapping between the database and extracted ontology does not require an Ontologist, manual mapping, or time intensive work to be done. In addition, the approach can be applied at a larger scale

    A Classical Technique to Prove the h-Cobordism Theorem

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    Let W be a compact and smooth manifold, whose dimension greater than 5, with boundary components V and V\u27. Suppose that W, V, and V\u27 are all simply connected, and the homology group of the pair (W, V) is trivial. The h-Cobordism Theorem States that W is diffeomorphic to a product cobordism. In this paper we will follow a classical technique developed by John Milnor in his \u22Lectures on the h-Cobordism Theorems\u22 half a century ago
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