VictorJuiz/thesis huggingface dataset:
Chemical communication of invasive weeds and opportunities for control in future environments [electronic resource]
Keywords: Biology.

Global Change is complex and its effects on ecology and plant-insect interactions are specific. Thus, it is vital to examine the nuances in plant behavior to better understand how to mitigate anthropogenic change. The more data points we can accumulate on the line of plant communication, the better we are able to assess the effects of change in natural systems. The invasion of Centaurea solstitialis (Yellow starthistle) is both a local and national crisis. Current and future increases in CO2 will lead to further aggressive expansion of this weed. In my work I have found that Yellow starthistle may be dependent on indirect defense prior to flower-head formation, within a tri-trophic system that may have co-evolved prior to introduction of Yellow starthistle to North America, and identified the volatiles likely acting as indirect defense cues. In this first known report on the influence of climate change on volatile emission of Yellow starthistle in the field, global changes such as elevated temperature and CO2 were not found to influence the volatile profile of the invasive. However, its induced emission as an anti-herbivory strategy may be more effective under elevated CO2, hence explaining its increased growth under such conditions. Thus, for natural control purposes, attention should be given to monitoring both herbivore and predator populations during early growth of this weed. This work offers insight into the evolutionary purpose of volatile emission and will help document the ways in which ecosystem responses to global change may be facilitated by networks of chemical communication.
Children's pragmatic reasoning from word choice [electronic resource]
Keywords: Psychology.

Listeners can learn from not just what speakers say, but also from how they choose to say it. Speech helps communicate both explicit information through the literal meaning of the words produced and also implicit information via pragmatic implications of intended meaning based on context. The ability to pick up on un- stated information conveyed through production choices is an important development for children because it allows them to infer meaning beyond what is said directly. Barner and colleagues (2011) posit that children's ability to compute scalar implicatures (e.g. that "some" implies some but not all) relies on their recognition of implied contrast with stronger lexical alternatives (i.e. that use of the weak quantifier "some" implies that its stronger competitor "all" could not have been used, or else an informative speaker would have said it instead). The Alternatives Hypothesis provides an elegant explanation for children's patterns of performance in scalar implicature tasks, and I extend this hypothesis to suggest that children's general pragmatic reasoning about word choice relies on their recognition of relevant alternatives in order to reason about speakers' intended meaning. I examine the predictions of the Alternatives Hypothesis using two case studies: children's computation of scalar implicatures and their inferences about category members from adjective use. Evidence from these experimental findings gives support that children are more successful at making pragmatic inferences when they are better able to consider relevant alternative descriptions a speaker could have used instead of the ones chosen. The ability to make inferences about speakers' intended meaning based on their production choices can help children learn to communicate more accurately and efficiently.
Children's reasoning about unconventional opinions as evidence for naive realism [electronic resource]
Keywords: Psychology.

It has long been argued in the literature on the development of theory of mind that children possess a precocious understanding of desires. One distinctive feature of desires is their subjectivity: different people want different things, and even if someone wants something unconventional, that person is not wrong and that want is not invalid. Contrary to this normative description, recent evidence suggests that both adults and preschoolers are susceptible to the influence of naive realism—the belief that "I see the world as it really is"—and in fact treat unconventional desires as unacceptable. Given this tension, in this dissertation, I explore the bounds of children's understanding of desires' subjectivity. I argue that children treat desires as subjective when they are able to analyze desires in terms of goal-directed behavior. In Study 1, children appropriately predict the behavior of that a character's desire will elicit, even when that desire is highly unconventional. In Study 2, I present preliminary evidence that children judge at least some unconventional desires to be acceptable when they are framed in the context of a goal. Taken together, these findings add important nuance to our understanding of children's desire psychology, highlighting the ways in which preschoolers' theory of mind may build on their understanding of goal-directed behavior.
Choosing Between Prevention and Catastrophe: Analyzing the Transformative Shift from Biodefense to Biosecurity Policy
Keywords: Center for International Security and Cooperation
CISAC
Biosecurity
Biodefense
Thesis

American biodefense policy was initiated following the 2001 Anthrax Attacks. Over the next thirteen years, policy enacted regarding biological threats and security measures shifted towards a biosecurity focus. Biosecurity is a broader concept that focuses on the nexus between health and security in order to combat a multitude of biological threats. This thesis analyzes two contradicting theories explaining this shift, in order to predict future trends: driving events, and changing landscapes.
The notion of driving events, that policy is created as a direct or indirect result of specific events, best explains the shift to bioterrorism policy in the early 2000s. However, the changing nature of the biological threat landscape cannot be overlooked in providing justification for this shift in policy. Rapid urbanization coupled with poor infrastructure, land use changes, increased international changes and climate change have had drastic impacts on the frequency and severity of infectious disease outbreaks over the last decade. These factors have continued to impact the frequency and pathology of emerging infectious diseases.

Biosecurity policy has become the default for American biological policy. Despite this, evidence suggests that another driving event would undoubtedly cause policymakers and politicians to revert back to bioterrorism policy. This characterization of this shift is a policy imperative, and cannot be taken lightly. In considering limited resource allocation, the government should be wary that any reactive bioterrorism investments in response to terror events could be an uneconomical venture, as policy is likely to default to biosecurity in the long run.
The choreography of Jim Crow [electronic resource] : race, performance, and the politics of touch
Keywords: Theater and Performance Studies.

Abstract: Considering the critical methods of performance studies, critical race studies, and sensorial studies, The Choreography of Jim Crow analyzes the creation of social identities through the rubric of touch—a tactile sensibility that provides a cultural foundation for the misperception of bodies as racialized subjects. This project approaches touch as a performative act that is both meaningful and with consequence. Specifically attending to the early 20th century historical period of Jim Crow because of its deeply held investments in the politics of separateness, this project asks: how do bodies become racially affirmed through the course of interaction? The 1896 landmark legal case Plessy vs. Ferguson, and the ensuing Supreme Court decision, upheld the constitutionality of individual states rights to racially segregate public facilities—under the now infamous "separate but equal" mandate—affirming the relationship between proximity and equality. Taking up tactility as a cultural system used to mark bodies as raced, The Choreography of Jim Crow employs literary and performance texts from the Jim Crow era to engage forms of power that have historically gone under-examined in relationship to racial politics. Through the tracing of a sensorial legacy of racial formation predicated on contact, The Choreography of Jim Crow grapples with the very present ways that American society underestimates the social, political, and cultural power that touch wields in our understanding of social identities.
Clicking the captives free [electronic resource] : digital activism in the anti-human trafficking movement
Keywords: Sociology.

This dissertation features three papers examining the use of digital activism within the anti-human trafficking movement. The first paper analyzes activists' web presence and strategies using quantitative web data and qualitative interview data, seeking specifically to understand how activists navigate the tension between structure and agency in a social space where norms have not yet been fully codified. The second paper uses data from interviews with activists to analyze how emotion work is done online, including personalizing statistics to generate moral shock and telling survivor stories to demonstrate efficacy and create hope for social change. The third paper contributes to the fields of social movement studies and digital activism by identifying three types of online goals that are well-suited to digital activism, namely user engagement, fundraising, and individual changes of behavior such as ethical purchasing decisions.
Coherent computation in degenerate optical parametric oscillators [electronic resource]
Keywords: Electrical Engineering.

Laws of physics have proved useful for solving combinatorial optimization problems. Simulated annealing and quantum adiabatic evolution are two of the well-celebrated algorithms designed according to fundamentals of statistical and quantum physics, respectively. This doctoral thesis introduces a new type of computing machine taking advantage of principles in quantum optics in hopes of speeding up the computation for some NP-hard problems. The machine is an open dissipative system with degenerate optical parametric oscillators (OPOs) as the basic building blocks. Properties that are considered contributing to the computational ability are the bistability of the output phase of each oscillator, coherent interaction between coupled oscillators, and the inherent preference of the system for oscillating in modes with the minimum photon loss. This thesis establishes a theoretical model for the network and studies its computing power through computational experiments on instances of an NP-hard problem in graph theory with the number of vertices ranging from 4 to 20000. The numerical results clearly demonstrate the effectiveness of the network.
Collider constraints on the phenomenological MSSM with neutralino and gravitino lightest supersymmetric particles [electronic resource]
Keywords: Physics.

As the Large Hadron Collider (LHC) begins Run II collisions at an unprecedented 13 TeV center-of-mass collision energy, it is important to take stock of the lessons learned from the Higgs discovery and the null results from searches for new physics, and also to understand how the LHC fits within the framework of rapid progress in flavor physics, dark matter detection, and cosmology. In this Thesis, I describe a numerical study of phenomenological MSSM (pMSSM) models, considering models with either of the two viable choices (a neutralino or a gravitino) for the lightest supersymmetric particle (LSP). After considering constraints on these models from flavor physics and early universe cosmology and exploring the relationship between model phenomenology and fine-tuning, I will describe how the viable parameter space is affected by LHC Run I searches, compare our results with simplified model exclusion limits, and describe important cases where the pMSSM results differ from simplified model analyses. I will also highlight cases where the LHC limits are degraded as a result of unusual decay topologies and/or displaced decays, discuss ways to improve the LHC's sensitivity to these scenarios, and show preliminary projections for the anticipated improvement in sensitivity that will result from the increased energy and luminosity in Run II. Finally, I will investigate how precise measurements of the couplings of the Standard Model - like Higgs can provide a complementary approach for exploring the pMSSM parameter space.
Collision avoidance up to the handling limits for autonomous vehicles [electronic resource]
Keywords: Mechanical Engineering.

As autonomous vehicles enter public roads, they should be capable of using all of the vehicle's performance capability, if necessary, to avoid collisions. This dissertation focuses on facilitating collision avoidance for autonomous vehicles by enabling safe vehicle operation up to the handling limits. The new control approaches first rely on a standard paradigm for autonomous vehicles that divides vehicle control into trajectory generation and trajectory tracking. A trajectory generation approach calculates emergency lane change trajectories, defined in terms of path curvature, that allows an autonomous vehicle to perform emergency lane changes up to its handling limits. Analysis also provides insights into when and to what extent a vehicle should brake and turn during an emergency lane change to maximize the number of situations in which a collision can be avoided. However, experimental results also highlight vehicle stabilization challenges associated with tracking paths defined by high rates of curvature change, which are desirable for emergency maneuvers. A link is forged between path curvature and vehicle performance, which inspires two trajectory tracking control designs. A four-wheel steering controller adds rear steering actuation to improve tracking and stabilization performance, while a two-wheel steering predictive controller incorporates future path information into current control actions. Experimental results demonstrate the advantages of each approach. However, separating vehicle control into trajectory generation and tracking is not always conducive to emergency maneuvers up to the vehicle's handling limits, where these aspects of vehicle control become tightly coupled with each other and with vehicle stabilization. An alternative paradigm is suggested that is more adept at controlling the vehicle in such scenarios. This approach integrates trajectory generation, trajectory tracking, and vehicle stabilization into one controller capable of mediating among the sometimes conflicting demands imposed by collision avoidance and stabilization. The controller can prioritize collision avoidance, above even stabilization, to minimize potential collisions. Experimental emergency lane changes and a mid-corner obstacle avoidance scenario highlight the advantages of this integrated approach to vehicle control.
Commitment, vertical restraints, and dynamic pricing of durable goods [electronic resource]
Keywords: Business.

Fixed price agreements are common in book markets. The agreements are industry wide and let the publisher set the retail price for a limited period. A natural experiment in the Norwegian book market weakened the vertical restraints in the Norwegian fixed price agreement. The fixed price period was shortened and the price restraint was softened to allow some retailer discounting. Two pronounced changes in the sales followed: The prices unravelled, and demand shifted from early at high prices to later at lower prices. The observed changes are not directly consistent with the traditional rationales for resale price maintenance, but instead show a loss of commitment. The commitment effects are quantified in a dynamic market equilibrium model with forward looking demand side and a forward looking supply side with a vertical structure at parameters estimated from the data. The analysis estimates the commitment effect of the fixed price agreement to be on the order of 2% beyond what resale price maintenance alone can explain.
Compact and efficient subharmonic OPOs for optical frequency comb applications [electronic resource]
Keywords: Electrical Engineering.

Optical frequency combs have become useful for applications in the mid-infrared such as frequency metrology and molecular spectroscopy. One tool for converting the infrared (IR) spectrum to the mid-infrared is the optical parametric oscillator (OPO). Specifically, the OPO operating at degeneracy, or the subharmonic of the pump, has been shown to preserve the salient frequency comb properties of the pump during the nonlinear conversion process. Previous demonstrations of subharmonic OPOs have generated broad bandwidths with low threshold requirements, however conversion efficiencies have been limited. Additionally, because femtosecond OPOs operating at degeneracy are generally synchronously pumped systems, the cavity lengths are typically constrained by the repetition rate of the pump laser. This dissertation presents the experimental results of three novel methods for implementing a synchronously pumped subharmonic OPO. The three designs are built around similar ring-resonator cavities. The designs focus on (i) increasing the OPO conversion efficiency to > 60%; (ii) reducing the overall size, or footprint, of the OPO using an optical fiber cavity while preserving < 100 fs operation; and (iii) increasing the repetition rate while also reducing the footprint of the OPO. First, a synchronously pumped subharmonic OPO was designed around a doubly resonant cavity. The nonlinear gain medium was a periodically-poled lithium niobate crystal designed to convert femtosecond pulses from a commercial 1-micron mode-locked fiber laser to 2 microns. Using high output coupling, the subharmonic OPO generated pulses as short as 40 fs with more than 600 mW of average output power and over 70% conversion efficiency. The synchronously pumped subharmonic OPO cavity was redesigned using single-mode optical fiber as a feedback loop in the cavity. Using two-types of optical fiber, exhibiting normal and anomalous dispersion, respectively, the OPO produced sub-100 fs pulses, generated a broad bandwidth, and achieved almost 40% conversion efficiency. The final design of a synchronously pumped subharmonic OPO cavity was built using a fractional length cavity design. A commercial mode-locked fiber laser operating at 100-MHz pumped an OPO cavity that was 1/5 the length of the typical synchronously pumped cavity length and generated a 500-MHz repetition rate signal.
Comparative analysis of CO₂ capture systems [electronic resource] : an exergetic framework
Keywords: Mechanical Engineering.

A portfolio of technology strategies will be needed to reach overall greenhouse gas emissions targets. Implementing systems to separate CO2 from atmospheric emissions of fossil-fuel power plants is predicted to be a necessary part of this portfolio, especially in the near term. However, existing carbon capture systems are quite inefficient, using or otherwise reducing a significant portion of power plants' electricity output. In order to improve future systems and make them viable, it is important to understand which aspects of each system have the most potential to improve, and which systems overall are most promising for future research and development. In this work, we examine three representative options for CO2 capture systems. The first option, an amine absorption system for post-combustion capture, is studied due to its relative technological maturity. The second system uses vacuum-swing adsorption and is examined as a post-combustion alternative to the amine system. The third option is a novel system using oxyfuel combustion in supercritical water, which facilitates CO2 separation while reducing the irreversibility inherent in fuel combustion. For each of these options, the current state of the system is modeled and assessed, and the potential for improvement of the system's efficiency is identified and discussed. This assessment is done via an exergy analysis, for several reasons. First, an exergy analysis provides a direct way to compare each process or unit operation to its thermodynamically optimal limit. This gives an immediate sense of how much improvement is actually still possible, thermodynamically, in that process or unit operation. Second, exergy analysis is a useful tool to compare---on a common basis---systems that use different types of inputs (heat vs. work vs. matter transfers), such as the three systems studied here. The first goal of this work is to give targeted recommendations for each type of system---and to discuss potential limitations---based on the results of the exergy analyses. A second goal of this work is to provide the correct theoretical modeling framework to allow an exergy analysis of these types of systems. Because each of these systems deal with non-standard fluids, calculation of thermodynamic properties relevant to performing an exergy analysis of these systems is not trivial. The relevant thermodynamic theory is extended where necessary, in particular in the case of the adsorption system.
Competing and cooperating phenomena in high temperature superconductors [electronic resource]
Keywords: Applied Physics.

In solid state physics, the presence of electron interactions leads to many interesting collective behaviors, such as superconductivity and magnetic and charge ordering. In particular, high temperature superconductors exhibit competing and cooperating phenomena due to the importance of charge, spin, structure, and orbital degrees of freedom. For iron pnictide superconductors, in some cases, their deep interplay may be present in experimental observations but only realized by accompanying theoretical considerations. In iron pnictides, mean field and T-matrix formalism expose the potential of tunneling experiments to deeply probe magneto-orbital cooperation. Additionally, angle-resolved photoemission displays the phenomenology of coexistent superconductivity and magnetism, which mean field considerations show to be a signal of fundamental competition between these two orders. Similarly, time-resolved X-ray diffraction displays structural deformations, the cooperative implications of which are revealed by considering the mean field effects of this deformation on magnetism. Finally, the focus shifts to fundamental studies of extended Hubbard models on superconductivity, where numerical exact diagonalization reveals competing charge phenomena. To understand interacting electron systems, experiments are vital, and sometimes a true appreciation is gained by accompanying theoretical studies.