VictorJuiz/thesis huggingface dataset:
Trait and State Based Experience of Awe Promotes Creativity

Creativity has many benefits and scientists seek to understand what fosters it. Extant research suggests that positive emotions foster creativity. Guided by the appraisal-tendency framework, which details how closely related emotions differentially influence cognitive processes, four studies (N = 1,508) documented that trait and induced awe, compared to amusement, promotes creativity. Two trait based studies found that awe-prone people in the USA, Iran, and Malaysia reported more creative tendencies (Study 1) and were more likely to solve a creativity problem (Study 2). Turning to state-based awe, people experimentally induced to experience awe were more likely than people induced with amusement to consider unconventional associations (Study 3) and generate original ideas (Study 4). However, Study 5 (N = 152) did not reveal significant difference across experimental conditions on the Duncker Candle Task using the actual materials in the laboratory. This is the first set of studies that documented the unique contribution that awe has on promoting creativity.

Advisor: Keltner, Dacher
Barter Exchange: Modeling, Analysis, and Participant's Strategy

In this study, we considered modern corporate barter platforms. We evaluated the probability of a participant on the platform being able to find an exchange partner(s) and his/her waiting time before being able to barter. Four stochastic models that characterize corporate barter platforms operating under different exchange mechanisms were analyzed. These models enable participants to concurrently barter with multiple partners in various exchange volumes. In addition, we prove that the platforms studied in the models are stable in terms of queueing theory, i.e., they do not expand such that there are infinite numbers of waiting participants. It was found that, under one of the exchange mechanisms (called online with pairwise exchange mechanism), the participants' waiting time is exponentially distributed. The expectation and variance (or their bounds) of waiting time were analyzed under other mechanisms also. Participants' preference was investigated based on the probability of being able to exchange and the corresponding waiting time under each exchange mechanism. Based on the participants' preference, suggestions for improving a platform's performance and profitability are provided accordingly./nContinued from the above results, participant's strategies under online with pairwise exchange mechanism are investigated. For a participant who implements EOQ model to purchase production materials, and who is willing to try barter to get rid of excessive inventories and barter-in production materials, a concise sufficient condition is developed to identify if it is beneficial to participate in a barter exchange. With the satisfaction of sufficient condition, if the participant cannot be matched with exchange partner(s) upon arrival, we suggest he always wait on the barter platform for future opportunities. While waiting, if his regular procurement and production plan does not permit back-order in production materials, a good strategy for the procurement of production materials during the waiting time is maintaining the usual practice with the regular supplier, and do not change the procurement activity until he is able to barter-in production materials. Additionally, if back-order in production materials is allowed during the waiting time on the barter platform, then a better temporary procurement plan with back-order may be available compared with no back-order allowed. We found a sufficient condition that justifies if back-order will be beneficial, and the sufficient condition becomes necessary as well if the participant's cost function (including ordering cost, inventory holding cost, and back-order penalty cost) is convex. Last but not least, though simultaneous trade-in and trade-out is a common practice in barter, we recommend that participants separate trade-in and trade-out processes to reduce the total waiting time. The reduction in waiting time may outweigh negative effects from the separation of trade-in and trade-out activities.

Advisor: Shen, Max
Metabolic strategies for enabling microbial-based green chemistry solutions

The field of green chemistry has been critical in helping reduce hazardous waste production in the chemical industry. An increasingly utilized approach in reducing waste has been the use of biocatalysts, enzymes, in industrial chemical processes. In the majority of applications of biocatalysts, single enzymes are used, however there remains the potential for further improving these syntheses using metabolically engineered organisms to synthesize small molecules in consolidated processes from renewable sugars. Here we present two strategies for improving the implementation of genetically engineered microorganisms for these green chemistry solutions. In the first strategy, we use combinatorial expression optimization to simultaneously vary expression of eight enzymes involved in the fungal xylose utilization pathway in Saccharomyces cerevisiae. We demonstrate how this tool can be used to map optimal expression space, which we apply to understanding how optimal expression changes with varying conditions. We also use this expression mapping to identify rate-controlling activities for subsequent engineering. In the second strategy, we describe the use of ester biochemical protecting groups as a means of controlling product reactivity. We propose protecting the indigo precursor, indoxyl, with either the base-labile acetyl or malonyl protecting groups for use in a green alternative to the current indigo dyeing process. Use of biochemical protecting groups to tailor chemical properties is a promising avenue to developing novel green chemistry applications for current bioproduction challenges.

Advisor: Dueber, John E
Chang, Michelle C
Star and Planet Formation Through Cosmic Time

The computational advances of the past several decades have allowed theoretical astrophysics to proceed at a dramatic pace. Numerical simulations can now simulate the formation of individual molecules all the way up to the evolution of the entire universe. Observational astrophysics is producing data at a prodigious rate, and sophisticated analysis techniques of large data sets continue to be developed. It is now possible for terabytes of data to be effectively turned into stunning astrophysical results. This is especially true for the field of star and planet formation. Theorists are now simulating the formation of individual planets and stars, and observing facilities are finally capturing snapshots of these processes within the Milky Way galaxy and other galaxies. While a coherent theory remains incomplete, great strides have been made toward this goal./nThis dissertation discusses several projects that develop models of star and planet forma- tion. This work spans large spatial and temporal scales: from the AU-scale of protoplanetary disks all the way up to the parsec-scale of star-forming clouds, and taking place in both contemporary environments like the Milky Way galaxy and primordial environments at redshifts of z~20./nParticularly, I show that planet formation need not proceed in incremental stages, where planets grow from millimeter-sized dust grains all the way up to planets, but instead can proceed directly from small dust grains to large kilometer-sized boulders. The requirements for this model to operate effectively are supported by observations. Additionally, I draw suspicion toward one model for how you form high mass stars (stars with masses exceeding ∼ 8 Msun), which postulates that high-mass stars are built up from the gradual accretion of mass from the cloud onto low-mass stars. I show that magnetic fields in star forming clouds thwart this transfer of mass, and instead it is likely that high mass stars are created from the gravitational collapse of large clouds. This work also provides a sub-grid model for computational codes that employ sink particles accreting from magnetized gas. Finally, I analyze the role that radiation plays in determining the final masses of the first stars to ever form in the universe. These stars formed in starkly different environments than stars form in today, and the role of the direct radiation from these stars turns out to be a crucial component of primordial star formation theory./nThese projects use a variety of computational tools, including the use of spectral hydrodynamics codes, magneto-hydrodynamics grid codes that employ adaptive mesh refinement techniques, and long characteristic ray tracing methods. I develop and describe a long characteristic ray tracing method for modeling hydrogen-ionizing radiation from stars. Additionally, I have developed Monte Carlo routines that convert hydrodynamic data used in smoothed particle hydrodynamics codes for use in grid-based codes. Both of these advances will find use beyond simulations of star and planet formation and benefit the astronomical community at large.

Advisor: McKee, Christopher F
The Futurist Imagination in the Radio Age

Radio waves not only transformed how bodies interacted with each other, but also gave modern writers and artists a new vocabulary with which to describe such connections. The “wireless imagination,” coined in 1912 by Filippo Tommaso Marinetti, would famously adopt the nascent technology of wireless communication as a model for the innovative poetics and electrified sensibility of the futurist movement. This dissertation reconsiders the influence of radio on Italian futurism in order to reorient our understanding of the avant-garde itself: from an aesthetics of shock and opposition towards one of receptivity and relation. In conversation with contemporary media/ntheory, I challenge a dominant identification of the “wireless imagination” with a mechanized, militant subjectivity through case studies of texts that have received little critical attention. Futurism’s interest in radio, as I demonstrate, extends beyond the technology itself, and its association with war, to a broader preoccupation with radio as radiance, a metaphor for sensation, connectivity, and address. I displace a broadcast model of one-way transmission in favor of a relational paradigm that complicates key tropes often associated with the avant-garde: its technocentrism; its hyper-masculinity; its ambivalent rapport with mass culture and politics. Across the dissertation’s three/nchapters, I describe modes of wireless interactivity that shed new light on the futurist subject and its relationship to others, within and outside the bounds of the texts under consideration. My analysis of Luciano Folgore’s Ponti sull’oceano (1914) in Chapter One reexamines futurist technophilia and its rhetoric of destruction through an emphasis on physical sensation and sympathetic vibrations. Chapter Two considers the gendered dynamics of communication through the subversive figure of the woman-as-wave, from/nF.T. Marinetti’s “Miss Radio” (1928) to Benedetta Cappa Marinetti’s Astra e il sottomarino (1935). Shifting from an individual and interpersonal to a collective wireless imagination, Chapter Three reads Fortunato Depero’s Liriche radiofoniche (1934) in the context of Italian broadcasting under fascism in order to reevaluate the avant-garde’s fraught integration with cultural and political life. This tension is the focus of the dissertation’s coda, which considers the fate of the “wireless imagination” on the eve of the Second World War in order to interrogate the possibilities and limits of the avant-garde itself.

Advisor: Spackman, Barbara
Somatotopic Precision of Whisker Tuning in Layer 2/3 of Rat Barrel Cortex

CHAPTER 1: Somatosensory maps in rodents & primates—a review/nThis chapter reviews basic principles and recent findings in primate, human, and rodent somatosensory maps. Topographic maps of the body surface are a major feature of somatosensory cortex. In primates, parietal cortex contains four somatosensory areas, each with its own map, with the primary cutaneous map in area 3b. Rodents have at least three somatosensory areas, and the whisker map in rodent primary somatosensory cortex is a canonical system for studying cortical microcircuits, sensory coding, and map plasticity./nMaps are not isomorphic to the body surface, but magnify behaviorally important skin regions, which include the hands and face in primates, and the whiskers in rodents. Within each map, intracortical circuits process tactile information, mediate spatial integration, and support active sensation. Functional representations are more overlapping than suggested by textbook depictions of map topography. Maps may also contain fine-scale representations of touch sub-modalities, or direction of tactile motion. In addition, somatosensory maps are plastic throughout life in response to altered use or injury./nCHAPTER 2: Somatotopic precision of whisker tuning in layer 2/3 of rat barrel cortex/nAlthough cortical maps of the sensory periphery are topographically organized at a large scale, the fine-scale precision of the map at the level of neighboring cells varies between species, sensory modalities, and cortical layers. In rodent somatosensory cortex, where each whisker is mapped to a dedicated cortical column, cells in layer 4 of each column are predominantly tuned to the appropriate whisker (columnar whisker; CW). However, in mice, cells in the upper cortical layers display locally heterogeneous "salt-and-pepper" tuning. It remains unclear whether the same heterogeneity is found in the upper layers of the rat whisker map. To address this question, we examined whisker tuning in regular-spiking (RS) and fast-spiking (FS) units recorded from layer 2/3 whisker columns in anesthetized rats. Among RS units, we observe a narrow majority (59%) best tuned to the CW; a clear majority (88%) with the CW among a statistically comparable group of "equal best" whiskers; and a small number (12%) of units best driven by one or more surround whiskers and poorly responsive to the CW. CW-tuned units display sharper tuning and faster responses to their best whisker than non-CW-tuned units, but are distributed evenly along vertical and horizontal dimensions of the column. These results demonstrate tuning in rat L2/3 that is more homogeneous than in mouse layer 2, but less so than in rat or mouse layer 4. FS units are tuned to the CW more frequently (78%) than RS units, consistent with broadly sampled input from local excitatory cells most responsive, as a group, to the columnar whisker.

Advisor: Feldman, Daniel E
Exploiting Magnetic Relaxation in x-Space Magnetic Particle Imaging

Magnetic particle imaging (MPI) is a new and rapidly developing imaging modality. Here we explore new ways to use MPI for molecular imaging and theranostic applications. A major focus is exploring methods to leverage the magnetic relaxation dynamics associated with the tracers used in MPI. In the context of canonical MPI implementations, these dynamics can reduce resolution and signal; however, they are also a source of molecular imaging contrast. In the first part of this thesis, we experimentally characterize relaxation in the canonical sinusoidal MPI implementation and explore novel ways to exploit this relaxation for colorized imaging and theranostic applications. In the second part, we describe a new approach to signal encoding in MPI that we call pulsed MPI (pMPI). We show that pMPI can allow one to fully prevent relaxation-induced resolution loss and can even provide ways to improve resolution over traditional continuous wave encoding techniques. Furthermore, pMPI can be leveraged to directly quantify magnetic relaxation that does occur and report this information in an imaging format as relaxation images (in contrast to the standard tracer mass/concentration images). Such approaches may pave the way for greatly improved color MPI and related molecular imaging methods. We believe a major takeaway from this work is that there remains significant untapped potential in MPI by way of unexploited physics. We believe development of these possibilities will be an exciting part of our field's future.

Advisor: Conolly, Steven
Inference on Graphs: From Probability Methods to Deep Neural Networks

Graphs are a rich and fundamental object of study, of interest from both theoretical and/napplied points of view. This thesis is in two parts and gives a treatment of graphs from two/ndiffering points of view, with the goal of doing inference on graphs. The first is a mathematical/napproach. We create a formal framework to investigate the quality of inference on/ngraphs given partial observations. The proofs we give apply to all graphs without assumptions./nIn the second part of this thesis, we take on the problem of clustering with the aid of/ndeep neural networks and apply it to the problem of community detection. The results are/ncompetitive with the state of the art, even at the information theoretic threshold of recovery/nof community labels in the stochastic blockmodel.

Advisor: Aldous, David
Reproductive decision-making under uncertainty: exploring the relationship of economic preferences and reproductive health

Little research has examined how economic uncertainty and preferences affect decision-making surrounding fertility intention, contraceptive behavior and pregnancy outcomes –an area where intention-behavior inconsistencies are widely acknowledged. Risk preference are defined as a person’s willingness to assume risk, and time preference as a person’s degree of present bias. Measures of risk and time preferences that underlie decision-making have been linked to health behaviors, especially substance use. There is a long history in social science of examining how these preferences correlate with financial decision-making and behavior, and measures have therefore been included in population surveys to examine economic behavior. Far less frequent are analyses that examine how economic preferences may extend beyond financial behavior to explain behavior in other domains, such as health behavior. Sexual and contraceptive behaviors are influenced by uncertainty surrounding pregnancy risk, pregnancy intention, access to methods, sexual and reproductive control, as well as perception of STI risk. Decision-making theory may therefore be especially helpful to shed light on disparities in unintended pregnancy and contraceptive use./nDrawing on behavioral economics, this dissertation expands understanding of uncertainty and reproductive health decision-making in several steps. My three papers examine if there are general decision-making constructs, including risk-taking propensity and degree of present bias that may extend beyond financial decisions to health behavior and ultimately reproductive health outcomes. In the first paper, I review the state of the literature on temporal and risk preferences and sexual and reproductive health. Next, I examine how risk preferences are related to sexual behavior and contraceptive use in the National Longitudinal of Youth (NLSY97). Finally, I examine the relationship between national economic uncertainty and pregnancy intentions and outcomes in the National Survey of Family Growth (NSFG). This work draws on economics, psychology, and social epidemiology./nThe goal of this research is to contribute to understanding the context of reproductive decision-making and behavior. This work deepens our understanding of the mechanisms underlying choices that drive health behavior. This is an important step towards predicting who will be at highest risk of adverse outcomes and develop models for intervention.

Advisor: Catalano, Ralph
Ahern, Jennifer
Effects of food insecurity and universal school meals on children’s dietary intake

This dissertation focuses on dietary intake patterns of children from low-income communities, and specifically the relationships of diet to food insecurity and school nutrition programs, respectively. The dissertation is divided into two parts. Part I discusses issues surrounding the measurement of food insecurity among children and provides support for the use of self-reported food insecurity measures, and for investigating effects that may differ by gender. Paper 1 explores the relationship between self-reported food insecurity and diet separately for boys and girls, using a dataset of 3,582 fourth and fifth grade students from San Diego area elementary schools. It concludes that among food-insecure children, gender may interact with food insecurity to influence eating behavior, with girls more prone than boys to alter their eating. Findings support a rationale to reduce child food insecurity and to address eating patterns that may place girls at greater risk for energy imbalances during critical periods of development./nPart II focuses on the role of school nutrition programs in reducing food insecurity and improving dietary intake among participants. It introduces the Community Eligibility Provision (CEP), discusses relevant legislation and political trends, and provides a conceptual framework for hypothesized pathways through which CEP may influence student outcomes. Paper 2 examines associations between CEP and school meal participation among students who are eligible for free or reduced-price meals (FRPM), near the eligibility cutoff but possibly eligible, or above the cutoff and ineligible, using a difference-in-difference framework and a cross-sectional national sample of 2,305 students from grades K-8. It finds that CEP is associated with higher participation in school breakfast and lunch, particularly among those who were above the cutoff and would not have had access to free or reduced-price meals through a 3-tiered application and certification model./nPaper 3 investigates associations among school meal participation, CEP, and dietary intake patterns using a larger sample of 4,124 students from grades K-8. It uses a regression framework to identify whether CEP is an effect modifier of relationships between school meal participation and dietary measures. It concludes that CEP is modestly associated with improved dietary intakes and may help reduce nutritional disparities for students in high-poverty schools. Finally, a special supplemental section explores the extent to which endogeneity in meal participation at CEP schools is a potential threat to these conclusions, using an instrumental variable approach to help control for omitted variables. There was no evidence to support the hypothesis that the dietary effects identified in Paper 3 resulted from shifting the source of student meals from home to school for the subset of students whose participation was induced by CEP. The dissertation concludes with a discussion of alternative explanations for the relationships found.

Advisor: Laraia, Barbara