VictorJuiz/thesis huggingface dataset:
Development and Validation of the Singapore Secondary Mathematics Self-Efficacy Scale

To understand the influence of self-efficacy on academic achievement, it is first necessary to assess the construct with reliability and validity. Although this has been done extensively in the Western context, studies on the reliability and validity of self-efficacy scores in Asian contexts have been scarce. The goal of this study is to develop a Mathematics self-efficacy scale with sound psychometric properties that can be used in future studies to advance our knowledge on the nature of self-efficacy in different cultural contexts. In this study, I described the development of a mathematics self-efficacy scale and present data on the reliability and structural validity of the scores in a sample of Singaporean adolescents (N = 1, 572). Results indicated that scale scores had strong internal consistency. Exploratory and confirmatory factor analyses suggested that there were two related but distinguishable self-efficacy variables: content-specific and general. There was also evidence for convergent validity, given the significant and positive correlations between the self-efficacy scores and related constructs. As was found in other studies, the difference between gender and the three self-efficacy scores was statistically but not practically significant for content-specific self-efficacy; there was not statistical difference in the general or combined self-efficacy scores. Finally, regression analyses suggested that self-efficacy scores made significant contributions to mathematics grade, even after taking into account the contributions of past achievement and other attitudinal constructs. Further research is needed to address the limitations and to ascertain the generalizability of these findings.

Advisor: Worrell, Frank C
Biomechanical Multifunctionality in the Ghost Crab, Ocypode quadrata

Bioinspired robotics has experienced unprecedented advancements. Robots can now run, swim and fly. Despite these advancements, the animals that inspired these robots remain substantially more versatile, using the same set of multifunctional appendages to perform many different tasks or behaviors. Understanding how biomechanics and behavior contribute to these capabilities will offer new insight into the science of animal movement and potentially inspire new multifunctional robotic technologies. Here, the ghost crab, Ocypode quadrata, was examined. These crabs, which are among the fastest land invertebrates, use relatively simple, unspecialized appendages to run, climb, burrow and dexterously capture prey. This dissertation focuses on ghost crabs’ burrowing and climbing behaviors. Both of these involve complex behavioral suites that involve the walking legs, the chelae and the body. Crabs demonstrated specialized postures, locomotion in confined spaces and goal-directed manipulation of both the environment and themselves. Both burrowing and climbing strategies involved compensatory strategies that allowed the crabs to maintain performance across a wide range of environmental conditions. Crabs do not rely on specialized appendage features but rather on the ability to use all appendages together. The findings presented in this dissertation represent new insight into the biomechanics of multifunctionality and offer inspiration for new bio-inspired robots with multi-use parts that permit, not simply obstacle negotiation, but also modification of the environment.

Advisor: Full, Robert J
Electronic Structure of Novel Materials for Next-Generation Devices

The properties of interfacial electronic states in device-relevant materials are investigated/nusing time- and angle-resolved two photon photoemission (TPPE) spectroscopy./nAngle- and time-resolved TPPE is used to investigate electronic states in the buffer layer/nof 4H-SiC(0001). An image potential state (IPS) series is observed on this strongly surface-bound buffer layer, and dispersion measurements indicated free-electron-like behavior for all states in this series. These results are compared with TPPE taken on bilayer graphene, which also shows the existence of a free-electron-like IPS series. Lifetimes for the n = 2, and n = 3 states are obtained from time-resolved TPPE; slightly increased lifetimes are observed in the bilayer graphene sample for the n = 2 the n = 3 states. Despite the large band gap of graphene at the center of the Brillouin zone, the lifetime results demonstrate that the graphene layers do not behave as a simple tunneling barrier, suggesting that the buffer layer and graphene overlayers play a direct role in the decay of IPS electrons. Ultrafast response of the room temperature ionic liquid (RTIL) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([Bmpyr][NTf2]) to a photoinjected electron is investigated in few-monolayer films using time- and angle-resolved two-photon photoemission spectroscopy. A delocalized precursor state and a localized solvated state are resolved at early times, but after 200 fs only a single solvated state is observed. The dynamics of film response to this solvated state are shown to depend significantly on film temperature and thickness. Population lifetime measurements demonstrate that the RTIL film can significantly affect the coupling between solvated state and metal substrate, as the solvated state’s average lifetime increases from 90 ± 20 fs in 1 ML films to 195 ± 83 ps in 3 ML films. Additionally, a temperature dependence of the time-dependent binding energy shift of the solvated state after c.a. 500 fs is attributed to a phase change occurring between the two temperature regimes that were investigated. Results from xenon overlayer experiments suggest that the solvation process occurs near the surface of the RTIL film. Finally, film degradation is found to be present, suggesting that the observed solvation response could involve a radical species. Valuable information about two very different interfacial materials is collected using TPPE, proving the power and versatility of the technique. The results presented here show that interfacial states can be used to monitor a variety of physical phenomena, from corrugation in graphitic materials to solvation and degradation in RTILs.

Advisor: Harris, Charles B
Design of Integrated Full-Duplex Wireless Transceivers

Demand for mobile data traffic is projected to exceed 30 exabytes per month in 2020, representing an over 100x increase since 2010. Prior generations of cellular deployments have serviced increased demand largely through use of more bandwidth - from 200KHz in GSM, to now 100MHz in CA-LTE. This method of scaling is closed, as low frequency spectrum has crowded and saturated. A proposed technique to enhance spectrum access in 5G deployments is agile full-duplex (FD) transceivers, which can transmit and receive at overlapped frequencies, or tune to arbitrarily spaced transmit/receive(TX/RX) frequency division duplexed (FDD) channels, to make use of available spectrum. The key problem in such a system is mitigating the interference the system's own transmitter creates for its receiver during simultaneous operation. Current implementations mitigate TX to RX interference at the antenna interface using off-chip, fixed-frequency duplexers, limiting a device's spectrum access to a handful of pre-defined, widely separated TX/RX band combinations. Accordingly, a universal mobile device tunable across global carrier band combinations does not exist./nThis work develops a transceiver architecture enabling simultaneous transmission and reception on a single single shared antenna, over a wide frequency tuning range, for FD/FDD systems. The architecture is enabled by an active TX replica which cancels interference at the RX input, a highly linear passive-mixer first receiver design based on class-AB transconductors which operates linearly in the presence of residual TX interference, and digital adaptation techniques which match the interference over time-varying operating conditions. Analysis is presented for the system's fundamental performance bounds in power and sensitivity, leading to noise mitigation techniques which minimize receiver degradation in the presence of the cancellation circuits. The analysis is validated by two chip prototypes, which demonstrate over $>$50dB cancellation of a +16dBm peak 20MHz TX signal, from 1GHz to 2GHz, up to an antenna VSWR of 5:1. This work demonstrates the potential for a fully integrated, frequency-tunable FD/FDD transceiver system, which could ultimately double existing mobile network capacity, and enable a universal duplexer-less radio.

Advisor: Nikolic, Borivoje
Our Breaths We Take: Outdoor Air Quality, Health, and Climate Change Consequences of Household Heating and Cooking with Solid Fuels

Worldwide, nearly 3 billion people—40% of the global population—burn wood, coal, and other solid fuels every day to cook their food; this number is even larger when including those who heat their homes with solid fuels as well. Exposure to pollution from heating and cooking fires causes about 3 million deaths each year, making it one of the biggest environmental health problems the world faces. The harm from this smoke is not restricted to those who breathe it, however: it contains gases and particles that contribute to global climate change as well./nChapter 2 shows that household cooking with solid fuels caused an estimated 12% of population-weighted ambient PM2.5 worldwide in 2010. Exposure to this air pollution caused the loss of 370,000 lives and 9.9 million disability-adjusted life years (DALYs) globally in the same year./nIn Chapter 3 I demonstrate that household heating with solid fuels caused an estimated 21% of population-weighted ambient PM2.5 in 2010 in Central Europe, 13% in Eastern Europe, 12% in Western Europe, and 8% in North America. Exposure to this air pollution results caused approximately 60,000 premature deaths in Europe, and nearly 10,000 deaths in North America, as well as an estimated 1.0 million disability-adjusted life years (DALYs) in Europe and 160,000 DALYs in North America./nChapter 4 addresses drivers of household wood combustion pollution in the San Francisco Bay Area, where the sector is the largest source of PM2.5 and regulators recently introduced amendments to wood burning rules for the airshed. Fireplaces are the source of the vast majority (84%) of PM2.5 from residential wood combustion in the San Francisco Bay Area, despite their use primarily as an aesthetic or recreational combustion activity. By evaluating hypothetical fuel and combustion device changeouts, I find that replacing fireplaces with gas would yield significant health and economic benefits. Specifically, retrofitting frequently used fireplaces (300,000 units) to gas inserts in the Bay Area’s nine counties would reduce sector emissions by about 90%, avoiding approximately 140-310 premature deaths and 19,000 lost days of work each year, and creating upwards of $1 billion in annual financial benefits from improved public health./nChapter 5 explains methodological overlaps and differences between the previous chapters. In Chapter 6, I explore the current regulatory and policy mechanisms specific to household heating with solid fuels, and relate these to the climate change implications associated with the sector. In Chapter 7, I highlight the relative dearth of data on household heating with biomass and its nuanced climate implications. This leads to a series of recommendations for future research, including collection of better household heating data in China and further work to understand how household combustion of biomass interfaces with both local air quality policy and climate change mitigation, outlining areas where this topic is currently visible in California.

Advisor: Smith, Kirk R
California forest and shrubland ecosystem changes in relation to fire, fuel hazard, and climate change

Fire is an integral ecological process, however fire’s impacts have been dramatically altered by people. In this dissertation I researched how fire ecology use to work and the vulnerability of ecosystems to fuel hazard reduction treatments by using a combination of experiments and landscape scale natural experiments throughout California. One of the best places to understand past fire behavior are the Wildland Fire Use areas in Sierran mixed conifer where I revealed that a forests’ environment, local-scale fire experiences, and regional fire experiences foster a rich, but sparse understory plant community. Throughout Yosemite National Park’s mixed conifer zone I examined the fire ecology of climate change refugia which have unique fire occurrence and severity patterns in frequent-fire mixed conifer forests of California’s Sierra Nevada: cold-air pool refugia have less fire and if it occurs, it is lower severity. In Northern California’s chaparral I examined fuel hazard reduction treatments and found that mastication and fire each have negative, yet unique influences on plant communities and fuel hazards which warrant examining other methods to protect people from chaparral fires. Overall these studies allow greater insight into our ecosystems and may help managers make informed fire management decisions.

Advisor: Stephens, Scott L
Data-efficient De novo Genome Assembly Algorithm : Theory and Practice

We study data-efficient and also practical de-novo genome assembly algorithm. Due to the advancement in high-throughput sequencing, the cost of read data has gone down rapidly in recent years. Thus, there is a growing need to do genome assembly in a cost effective manner on a large scale. However, the state-of-the-art assemblers are not designed to be data-efficient. This leads to wastage of read data, which translates to a significant monetary loss for large scale sequencing projects. Moreover, as technology advances, the nature of the read data also evolves. This makes the old assemblers insufficient for discovering all the information behind the data. Therefore, there is a need to re-invent genome assemblers to suit the growing demand./nIn this dissertation, we address the data efficiency aspect of genome assembly as follows./nFirst, we show that even when there is noise in the reads, one can successfully reconstruct the genomes with information requirements close to the noiseless fundamental limit. We develop a new assembly algorithm, X-phased Multibridging, is designed based on a probabilistic model of the genome. We show, through analysis that it performs well on the model, and through simulation that it performs well on real genomes./nSecond, we introduce FinisherSC, a repeat-aware and scalable tool for upgrading de-novo haploid genome assembly using long and noisy reads. Experiments with real data suggest that FinisherSC can provide longer and higher quality contigs than existing tools while maintaining high concordance. Thus, FinisherSC achieves higher data efficiency than state-of-the-art haploid genome assembly pipelines./nThird, we study whether post-processing metagenomic assemblies with the original input long reads can result in quality improvement. Previous approaches have focused on pre-processing reads and optimizing assemblers. We introduce BIGMAC, which takes an alternative perspective to focus on the post-processing step. Using both the assembled contigs and original long reads as input, BIGMAC first breaks the contigs at potentially mis-assembled locations and subsequently scaffolds contigs. Our experiments on metagenomes assembled from long reads show that BIGMAC can improve assembly quality by reducing the number of mis-assemblies while maintaining/increasing N50 and N75. Thus, BIGMAC achieves higher data efficiency than state-of-the-art metagenomic assembly pipelines./nMoreover, we also discuss some theoretical work regarding genome assembly in terms of data, time and space efficiency; and a promising post-processing tool POSTME in improving metagenomic assembly using both short and long reads.

Advisor: Rao, Satish
Mass Transport of Condensed Species in Aerodynamic Fallout Glass from a Near-Surface Nuclear Test

In a near-surface nuclear explosion, vaporized device materials are incorporated into molten soil and other carrier materials, forming glassy fallout upon quenching. Mechanisms by which device materials mix with carrier materials have been proposed, however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. A surface deposition layer was observed preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused. Eleven such boundaries were studied using spatially resolved analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nano-scale secondary ion mass spectrometry (NanoSIMS), we identified higher concentrations of uranium from the device in 7 of the interface layers, as well as isotopic enrichment (>75% 235U) in 9 of the interface layers. Major element analysis of the interfaces revealed the deposition layer to be chemically enriched in Fe-, Ca- and Na-bearing species and depleted in Ti- and Al-bearing species. The concentration profiles of the enriched species at the interface are characteristic of diffusion. Three of the uranium concentration profiles were fit with a modified Gaussian function, representative of 1-D diffusion from a planar source, to determine time and temperature parameters of mass transport. By using a historical model of fireball temperature to simulate the cooling rate at the interface, the temperature of deposition was estimated to be ∼2200 K, with 1σ uncertainties in excess of 140 K. The presence of Na-species in the layers at this estimated temperature of deposition is indicative of an oxygen rich fireball. The notable depletion of Al-species, a refractory oxide that is highly abundant in the soil, together with the enrichment of Ca-, Fe-, and 235U-species, suggests an anthropogenic source of the enriched species, together with a continuous chemical fractionation process as these species condensed.

Advisor: van Bibber, Karl
Knight, Kim
The Development of Esoteric Buddhist Scholasticism in Early Medieval Japan

In the late eleventh century, a scholastic monk at the monastic center of Ninnaji compiled the first catalogue of writings by the cultural hero and revered founder of the Shingon school of esoteric Buddhism in Japan, Kōbō Daishi Kūkai. Among these works, the Treatise Distinguishing the Two Teachings of the Exoteric and Esoteric was praised as the premier tractate on esoteric Buddhist doctrine and the foundational document of Shingon school. The Treatise continued to play a central role in the formation of a Shingon sectarian identity, inspiring numerous medieval commentaries as well as studies by modern scholars. However, there is no evidence that this seminal doctrinal treatise ever existed before appearing in catalogues in the late eleventh and twelfth centuries. In this dissertation, I explore the textual history of the Treatise on the Two Teachings and call into question the legitimacy of its origin. Furthermore, by comparing the content of this text with two late ninth-century compendia on esoteric Buddhist doctrine, I propose that the Treatise may have been a polemical response to post-Kūkai developments in the Tendai school. Ultimately, I conclude that esoteric Buddhism in Japan developed as a scholastic discourse regarding the path toward buddhahood. This discourse was not the creation of a semi-legendary founding figure, nor can it be reduced to a single foundational text. Rather, esoteric Buddhism was a scholastic tradition consisting of sundry perspectives and interpretations that developed over the course of centuries. The Treatise on the Two Teachings reflects a decidedly contentious example of this tradition.

Advisor: Sharf, Robert
Investigating Life Histories and Taskscapes through Microscale Geoarchaeological Analysis in Fort Davis, Texas from the 1870s to 1930s

This project applies microscale geoarchaeological analysis to four sites from late 1800s and early 1900s in Fort Davis, Texas in order to reconstruct life histories, past taskscapes, and show the potential of geoarchaeological analysis in a historic archaeology context. The military post at Fort Davis was established in 1854 along the San Antonio-El Paso road through the high Chihuahua Desert in Far West Texas. The civilian town of Fort Davis quickly formed near the post. After withdrawing during the Civil War, the army reoccupied the Fort in 1867 and over the next twenty years it was periodically home to every company of African-American “Buffalo Soldiers” in the United States army. In 1961 the Fort became a National Historic Site under the National Parks Service. The four sites investigated in this dissertation include two residences on Fort property which date to the 1800s: the Laundresses’ Quarters and the Enlisted Married Men’s Quarters. Two additional sites are from civilian areas of town: the Smith-Carlton Casa Vieja (the oldest standing, continuously occupied adobe structure in town), and a midden and nearby foundations on the Francell-Byerley Property which date to the 1920s and 1930s. Analysis at each site focused on a combination of fundamental soil chemical analyses (soil pH and soil organic matter) and microstratigraphic methods (particle size analysis and soil micromorphology). These approaches, combined with historical data, are used to develop life histories for each of the four sites. Additionally, taskscapes associated with residence and discard activities (the tasks most commonly represented in the four sites) are discussed. These analyses show how microscale archaeology, rarely incorporated into historical archaeology projects, can provide a significant line of evidence when combined with archaeological and historical sources.

Advisor: Maher, Lisa A