VictorJuiz/thesis huggingface dataset:
Emerging electronic states at boundaries and domain walls in quantum materials [electronic resource]
Keywords: Applied Physics.

Boundaries and domain walls in condensed matter often host unique electronic states that are distinct from those living inside the bulk. Their intriguing physics and diverse application potentials have attracted growing research effort on codifying the relevant emergent laws, whereas their complex and low-dimensional nature constantly calls for novel characterization techniques. Scanning Microwave Impedance Microscopy (MIM) characterizes local electrical response (complex permittivity) by probing microwave tip-sample admittance in the meso- to microscopic scale. It has matured in the past decade and has become a powerful tool for studying these emerging electronic states in real space, highly complementary to existing tools working in atomic scale or momentum space. In this dissertation I will first give a scientific overview of the field (Chapter 1), followed by a brief introduction to MIM, with a focus on the fundamental principles and recent developments (Chapter 2). I will then present five scientific studies made possible by MIM, which can be grouped into two categories, namely 1D edge states at solid-vacuum boundaries in 2D systems (Chapter 3), and order-parameter domain walls embedded in a 3D solid (Chapter 4). Chapter 3 contains the discovery of unexpected edge conduction in HgTe/CdTe quantum wells in the presence of a strong magnetic field, an unconventional correlation between quantum Hall transport quantization and bulk Landau level filling in gated graphene devices, and edge-bulk conductivity contrast in magnetic modulation doped Cr-(Bi, Sb)Te films in the quantum anomalous Hall regime. Chapter 4 includes the signature of charge-order domain walls with enhanced conductivity in a layered magnanite, and the establishment of neodymium iridate as the first experimental realization of a magnetic insulator with metallic magnetic domain walls.
Empirical models of analyst forecasts [electronic resource]
Keywords: Business.

This dissertation is comprised of two studies on analyst forecasts. The first study provides empirical evidence about the objective function underlying analysts' choice of forecasts. Assumptions about sell-side analysts' objective function are critical to empirical researchers' understanding of their incentives and resulting behavior. In contrast to approaches used in previous papers which rely exclusively on statistical properties of forecasts, I compare theoretical models with alternate objective functions based on their ability to explain observed forecasts. A linear loss objective function which incorporates the effect future analysts' actions on analysts' deviation from peer forecasts is best rationalized by the data. I find that assumptions about the objective function have a substantial impact on the conclusions from empirical tests about analysts' incentives and behavior. The second study provides empirical estimates of uncertainty and disagreement about future earnings that underly analyst forecast dispersion. A parsimonious model which assumes that analysts' payoffs are jointly determined by forecast error and deviation from consensus reproduces many of the descriptive facts observed about forecast dispersion in the data. The strategic behavior that arises from the model distorts both the levels of forecast dispersion and the sensitivity of the measure with respect to cross-sectional variation in uncertainty. The estimated parameters perform better at predicting forecast dispersion out-of-sample than approaches based solely on regressions that use firm characteristics. Counterfactual simulations indicate that analysts' strategic incentives, together with the sequential forecast setting, plays a first-order role in determining forecast dispersion relative to the firm's information environment. The model-implied estimates of earnings uncertainty exhibit a substantially less negative association with future returns relative to the association generated by forecast dispersion. This finding partially reconciles the findings from previous studies with theories about the asset pricing implications of uncertainty and disagreement.
Empirical studies in operations management and pricing with customers [electronic resource]
Keywords: Business.

This dissertation studies problems in operations management that arise in settings characterized by rich interactions with customers, especially online. We first study the pricing and inventory strategies of a retailer whose customers can monitor its offered prices over time through an online channel, where they incur heterogeneous costs to monitor. We then study the growth and customer loyalty of online services in the app economy from an operational perspective. We describe each of these settings and empirical inquiries in turn. Online retail reduces the costs of obtaining information about a product's price and availability and of flexibly timing a purchase. Consequently, consumers can strategically time their purchases, weighing the costs of monitoring and the risk of inventory depletion against prospectively lower prices. At the same time, firms can observe and exploit their customers' monitoring behavior. Using a dataset tracking customers of a North American specialty retail brand, we present empirical evidence that monitoring products online is associated with successfully obtaining discounts. We develop a structural model of consumers' dynamic monitoring to find substantial heterogeneity, with consumers' opportunity costs for an online visit ranging from
Enabling more sustainable affordable housing [electronic resource] : utilizing early design stage life cycle assessment to reduce life cycle costs and environmental impacts
Keywords: Civil and Environmental Engineering.

Residential building structures contribute significantly to social, environmental, and economic impacts throughout their life cycle. Sustainability, is broadly concerned with these impacts and how they relate to complex social, environmental, and economic systems such as those that drive the residential built environment. This thesis presents a methodology for promoting more sustainable housing development by introducing environmental and economic impact feedback into the early design stage. The social dimension is addressed by focusing this research on affordable housing for low-income households. The environmental and economic impacts are addressed by integrating life cycle assessment and life cycle costing techniques into an automated, parametric analysis framework. This framework is applied to two low-income, affordable housing design spaces in the contrasting environments of San Francisco, California and Las Vegas, Nevada. The thesis illustrates how this methodology can aid design stakeholders in reducing the long-term environmental impacts and costs of low-income, affordable housing developments. The results are also compared to industry design preferences, collected through a survey of low-income, affordable housing practitioners. This comparison reveals potential gains in life cycle environmental impact and cost reductions that are not currently realized by prevailing industry design preferences. This thesis concludes by offering direction for future work and by highlighting the potential for this framework to inform housing development trends and regulatory decision-making.
Enacting perception [electronic resource] : the contemporary lyrical novel
Keywords: Comparative Literature.

My dissertation studies the hybrid genre of the lyrical novel primarily in the post-1980 period. Considering lyrical novels a potential praxis, it argues that lyricism in narrative can result in a reader's experience resembling a process of perception that is enactive. I discuss Julio Llamazares' La lluvia amarilla, Horacio Castellanos Moya's El asco, Yoko Tawada's Wo Europe Anfängt?, W.G. Sebald's Austerlitz, and Abdelkébir Khatibi's Amour bilingue as contemporary lyrical novels that inquire into the limits of reality and fiction, into memory, self, and poetic language.
An energy harvested ultra-low power wireless transceiver for biomedical implants [electronic resource]
Keywords: Electrical Engineering.

Biomedical implants have been used to treat a variety of medical conditions as well as to monitor vital physiological information in the body. Advances in manufacturing technology for bio-materials and electronics have expanded the prospect of widespread use for these implants. Significant hurdles have to be overcome before these devices go mainstream. Power delivery to the implant is one of the major challenges faced by these systems. Although it is possible for batteries to supply uninterrupted power to certain kinds of implants, e.g. pacemakers, other implant applications need to be powered remotely from outside the body. RF powering is a widely used method among remote powering techniques for implants. Reducing the size of these devices is also highly desirable such that they could be implanted using less invasive surgical procedures. A wireless communication link enables information exchange with the implant using two sets of transceivers: one outside and one inside the body. The transceiver which is embedded in the implant has to be designed meeting stringent power, size, and data-rate requirements. In this thesis, an energy harvested ultra-low power wireless transceiver for biomedical implants is demonstrated. The transceiver is fully RF-powered at low gigahertz carrier frequencies suited for optimal power delivery using the midfield wireless powering technique. It demonstrates megabits-per-second data rates aimed at neuro-modulation and recording applications with large number of channels. The transceiver supports full duplex operation via frequency-division (FDD) or time-division (TDD) duplexing methods with a high energy efficiency. In FDD mode, the transceiver achieves maximum data rates of 58 Mbps in TX, and 2.5 Mbps in RX. The average power consumption of the transmitter is 93 μW at 58 Mbps while that of the receiver is 7.2 μW at 2.5 Mbps. This corresponds to an energy-per-bit metric of 2.9 pJ/bit for the RX and 1.6 pJ/bit for the TX. In TDD mode, data rates of 7.2 Mbps for the TX and 1.8 Mbps for the RX have been demonstrated. In this mode, The TX consumes 54 μW, while the RX consumes 9.4 μW. The transceiver, therefore, achieves energy efficiency of 7.5 pJ/bit for the TX and 5.2 pJ/bit for the RX. This radio was fabricated in 40 nm CMOS LP process and has a small silicon area of 0.8 mm2.
Engineering bivalency and bispecificity in protein therapeutics and protein scaffold development [electronic resource]
Keywords: Chemical Engineering.

Multivalent and multifunctional proteins are abundant in nature. The avidity effect, a core principle of multivalent molecules, allows these proteins to tune biological functions and responses across a large dynamic range with varying specificity. Many protein therapeutics also take advantage of this evolvable tunability, the canonical example being the antibody. This thesis consists of two separate sections. Section One: I focus on the avidity effect of multivalent proteins and its therapeutic uses. As an illustrative case, our lab had previously created a protein variant that monomerically binds the c-MET tyrosine kinase. By dimerizing this variant, we find that we greatly increase its efficacy through increased apparent affinity to cell surface c-MET. Section Two: I focus on multispecific proteins and their uses in medical applications. Most current therapeutic protein scaffolds are single protein domains with monomeric binding and function. Combining these scaffolds to create multispecific functionality presents manufacturing challenges. Here the vascular endothelial growth factor (VEGF) protein is used as a stable, naturally bivalent scaffold for engineering bispecific proteins.
Engineering of light emission devices for integration on silicon [electronic resource]
Keywords: Electrical Engineering.

Silicon (Si) compatible lasers for applications in inter die and intra die optical interconnect systems and spectroscopy system have been an interesting topic for several years, but has yet to be practically demonstrated. One possible candidate material of a light source for inter die and intra die optical interconnect systems is germanium. Germanium (Ge) is compatible with Si and has a direct band gap of 0.8 eV, corresponding to the usual communication wavelength of 1550 nm. The small difference of 0.134 eV between the direct and indirect band gaps of Ge suggests the possibility of a radiative direct band gap transition. In the first part of this work, we focus on improving different aspects of Ge to reach the goal of lasing with a low threshold. The first aspect is the activated n-type dopant concentration and crystal quality, which we improve through a novel method of laser annealing, microwave annealing and co-implantation of dopants. The second aspect is the increase in the concentration of electron density in the active region through implementation of a unique electrical device design, known here as a gated microdisk resonator. The third aspect is the improvement in optical property by reducing the radiative recombination in the indirect valley through the fabrication of a photonic crystal. For spectroscopy applications, one candidate is thulium (Tm). We can dope the dielectrics with Tm3+ ions and pumped it at 1570nm taking advantage of light sources already used in telecommunications. This laser can be tuned to lase in the range from 1650nm to 2000nm depending on the matrix and the pump. This wavelength range can also be used in (light detection and ranging) LIDAR systems, gas sensing systems, spectroscopy on a chip and even to extend the range of wavelengths for telecommunications. In this second part of the work, we demonstrate photoluminescence with Tm-doped dielectrics and also show a method to optimize the microdisks for lasing with Tm.
Engineering the NK1 Fragment of the Human Hepatocyte Growth Factor for Dual Use as a Potent Agonist and a Gene Therapy Delivery Vehicle
Keywords: NK1
HGF
growth factor engineering
protein engineering
supercharged proteins
gene delivery
wound healing
regenerative medicine
bioengineering
Thesis

Regenerative medicine and wound healing are critically relevant topics in the current medical field. Estimates have placed the total number of patients impacted with chronic wounds in the US at 6.5 million, resulting in an annual expenditure of US$25 billion. Furthermore, the regenerative medicine industry has taken off, reaching over US$3 billion in both gross annual spending and sales. Growth factor-based therapies for use in regenerative medicine have shown initial promise in pre-clinical testing, but numerous obstacles to effective delivery and translation of expected activity have limited growth factors’ clinical potential. Accordingly, growth factor engineering techniques have been developed and employed to improve clinically relevant characteristics such as stability, circulation time, expression yield, and delivery methods. However, as is often the case in clinical applications, extremely potent therapeutics must be engineered to enable significant impact. This study integrates design and delivery methodologies from the fields of gene therapy and supercharged protein engineering to investigate the potential for the NK1 fragment of HGF to serve as a dual-use exogenous mitogen and plasmid delivery agent. Successful internalization was shown and characterized in mammalian cell systems. Additionally, rational engineering of covalent dimerization via the introduction of an N-terminal cysteine residue enhanced mitogenic activity in a number of NK1 variants. Finally, initial evidence is put forth for the ability of NK1 variants to complex with DNA, a critical step in preparing nonviral protein-based delivery vehicles for gene therapy applications.
Enhanced thermionic energy conversion with a graphene anode [electronic resource]
Keywords: Physics.

Thermionic energy converters (TECs) are a direct heat-to-electricity conversion technology with the potential to outperform the current state-of-the-art solid-state energy conversion technologies in a wide range of working temperatures. TECs could not only be applied to large-scale power plants in a tandem cycle, but could also be deployed in distributed power generation systems at small scales. In a TEC, electrons evaporate from a hot electrode (the cathode) into a vacuum gap and are collected by a cooler electrode (the anode) to generate electric energy. However, the published TECs suffer from low output voltage as well as low output current because the work function of the anode is too high and the space charge barrier in the inter-electrode is too strong, which ultimately lead to low conversion efficiency. In this thesis, I will first present a phenomenological model to calculate a material's work function. This model shows that graphene has great potential to yield an ultra-low work function. I will then experimentally demonstrate such a graphene anode in an ultra-high vacuum system. The graphene is grown on a piece of copper foil by chemical vapor deposition. It is then transferred onto a 20 nm thick HfO2 layer prepared by atomic layer deposition on silicon. After in-situ deposition of a monolayer of Cs/O, the work function of the graphene anode is dramatically reduced from 4.62 eV to 1.25 eV. Furthermore, I will show that electrostatic gating graphene through the HfO¬2 dielectric layer can further reduce the work function of graphene. Due to the absence of surface Fermi level pinning and low surface state density according to graphene's linear dispersion relation, the Fermi level of graphene can by effectively raised through a DC bias with negligible energy consumption. I will show that combining Cs/O surface coating and electrostatic gating would lead to a world-record low work function for graphene of 1.0 eV. Finally, I will demonstrate a TEC prototype based on this graphene anode, together with a commercial dispenser cathode. At the cathode working temperature of 1000 ˚C, the work functions of both of the electrodes are reduced by Ba. In addition, this TEC prototype deploys a nano-manipulator system that can reduce the inter-electrode gap to 17 μm, leading to a much reduced space charge barrier. By addressing the two challenges simultaneously, a low work function anode and minimizing the space charge barrier, the overall conversion efficiency of this TEC prototype is improved by a factor of over 50, with an estimated maximum electronic conversion efficiency of 9.8 %, which is the highest reported by far at this relatively low working temperature.
Equal opportunity for political influence in democratic problem-solving [electronic resource]
Keywords: Political Science.

How can democratic governance both incorporate high-quality outcomes and preserve equality of status and voice in decision-making? This dissertation contributes to liberal democratic theory by examining democracy's ability to solve collective problems. Solving a collective problem well through majority rule requires identifying and weighting competent input more heavily. Constructive political inequality (CPI) is what I call the unequal political influence that is necessary to solve collective problems well. CPI and the disagreement about the best means to a solution are beneficial parts to solving collective problems, yet neither are well-accommodated in contemporary liberal democratic theory. The democratic problem-solving framework I develop here presents itself as a hybrid of the two prevailing approaches in liberal democratic theory: the aggregative conception developed by Schumpeter ([1942] 1962) and Riker (1982) on one hand, and deliberative democracy developed by Cohen (1989) and others on the other hand. Equal opportunity is often relied upon to govern political influence through persuasion, but existing accounts of the principle do not sufficiently distinguish equal opportunity from equality of outcomes, the role of individual choice to be politically influential, and a statistically equal chance for influence. I show that equal opportunity is different from its colloquial use as merely a principle of non-discrimination. An appropriately specified conception of equal opportunity yields a basis for non-discrimination as well as a basis of explicit discrimination. To show how this new conception of equal opportunity for political influence can be applied to actual electoral reform proposals, I examine the use of vouchers to fund elections and the use of mini-publics to influence public opinion. Equal opportunity for political influence, appropriately specified, contributes to a better theoretical framework to motivate each of these reform proposals.
Essays in applied economics [electronic resource]
Keywords: Economics.

The first chapter is co-authored with Kevin Hoan Nguyen. Changes in the technology format of popular music distribution are nothing new. Vinyl records and cassette tapes disappeared in the 1990s, CDs faded out in the 2000s, and digital downloads began their decline in the 2010s to make way for streaming subscriptions and on-demand radio. We use data from Billboard's Hot 100, a weekly ranking of the most popular songs in the United States, to investigate the impact of technology format changes on the popularity characteristics of these songs. We find that the transition from CD to digital impacts popularity characteristics significantly. The digital technology format reduces the cost of releasing a single, which allows established artists to crowd out the Hot 100 by virtue of their reputation. Faster feedback mechanisms lead to the emergence of "one-week wonders" -- i.e., songs charting on the Hot 100 for only a week before disappearing. Once a song manages to survive the initial vetting process, the digital format facilitates discovery and allows the song to remain popular for longer than previously possible. The second chapter is co-authored with Kevin Hoan Nguyen. We investigate the effect of the Australian Youth Participation in Education and Training Reform, an unusual policy implemented from 2003 to 2010. The reform introduced a new phase of compulsory participation, where students must either stay in school, take approved vocational courses, attend an apprenticeship, work full-time, or any combination of the above. We find that almost half of the students -- who would have left school early absent the compulsory participation phase -- undertake training, employment, or other courses, suggesting that the policy induces a different set of compliers compared to traditional compulsory schooling laws. Although there is considerable heterogeneity in the effects on education attainment by socio-economic status and gender, the reform raises the total years of schooling by 0.14 years and the high school attainment level by 5.8 percent. The reform significantly raises wages and income for the treated cohorts. The third chapter is co-authored with Petra Moser. Policy changes in 1996 and 2012 retroactively placed thousands of foreign compositions, such as Sergei Prokofiev's Peter and the Wolf, under copyright in the United States. Critics argue that long-lived copyright terms limit access to important compositions for all but the most affluent U.S. orchestras, but there is little systematic evidence. This paper examines repertoire data for U.S. symphonies between 1842 and 2012 to investigate the impact of copyright on the diffusion of classical music. We find that copyright is a key determinant of the types of music that U.S. orchestras play, and that copyright disproportionately impacts orchestras that are more budget-constrained. Repertoire data also indicate that a lack of copyright protection helped popularize Russian music in the United States.