VictorJuiz/thesis huggingface dataset:
Is Enrollment into Graduate School Affected by the Business Cycle?
Keywords:  Department of Economics
Stanford Department of Economics
postgraduate education
graduate school
recession
human capital theory
graduate programs
unemployment
labor market
educational attainment
business cycle
Thesis

In the current economic climate, reports of increased enrollment at graduate school programs frequently appear in the media. This increased enrollment is generally attributed to the declining opportunity cost of education during times of economic weakness, and thus increased investments in education as opposed to employment. Another potential effect of economic weakness on educational attainment, often overlooked, is a decline in the ability to fund education, or the credit constraints effect. Evidence in the current economic literature documents the existence of both the opposing opportunity cost and credit constraints effects of the business cycle on educational attainment. However, the empirical relationship between educational attainment and the business cycle has been primarily studied only at the level of college and high school education. This study seeks to answer the question: Is enrollment into graduate school affected by the business cycle? Specifically, I use a modified Human Capital Theory Model, and enrollment data from 1976-2005, to examine the effects of key economic indicators (the unemployment rate, employment growth, GDP growth, personal income growth, and personal disposable income growth) on changes in graduate enrollment in the United States.
Laser-based diagnostics for hydrocarbon fuels in the liquid and vapor phases [electronic resource]
Keywords: Mechanical Engineering

Laser-absorption measurements of fuel concentration are widely used in engine development and for studying the combustion chemistry of hydrocarbon fuels. Direct injection of liquid fuel is common in many combustion technologies (e.g. internal combustion engines and gas turbine engines), however, these multiphase (gas and liquid) environments present significant challenges to laser-absorption measurements. These challenges include optical scattering from liquid fuel droplets and strong optical absorption from liquid fuel films. This thesis describes the development of two novel multi-phase diagnostics. Developing these diagnostics required quantitative measurements of the previously unknown refractive index spectra of several liquid hydrocarbons (n-decane, n-dodecane, and several gasoline samples). These measurements are presented, revealing important characteristics of liquid fuels. The first diagnostic developed uses three laser wavelengths for measuring fuel-vapor mole fraction and temperature in evaporating aerosols. Demonstration measurements were made over a large range of temperatures and fuel loadings in an aerosol shock tube, providing the first known laser-absorption measurements of vapor concentration and temperature in an evaporating fuel spray. The second diagnostic uses two laser wavelengths for measurements of fuel-vapor mole fraction and liquid fuel film thickness. The first known laser-absorption measurements of fuel vapor and liquid film thickness were demonstrated in the laboratory. These diagnostic techniques have been incorporated into a commercial sensor for engine development.
A microfluidic biochip based on magnetoresistive detection of nanoparticles [electronic resource]
Keywords: Materials Science and Engineering

The detection of magnetic nanoparticle (MNP) labels is a promising alternative to optical detection of fluorescent labels in biomolecular assays, in part because MNPs are not susceptible to pH, bleaching, or autofluorescence, but especially because microscopic quantities of MNPs can be detected with simple and inexpensive magnetoresistive sensors such as spin valves. The goal of this dissertation was to develop and demonstrate a biochip based on this detection principle. The particular novelty of this work is the extensive demonstration of magnetic biochips in real assays, the establishment of a compatible microfluidic fabrication process, and the development of a simple mathematical model which explains the experimentally observed signal scaling trends.
Modeling the martian surface using bistatic radar at high incidence angles [electronic resource]
Keywords: Electrical Engineering.

A bistatic radar system uses a transmitter and receiver in two separate locations to measure electromagnetic wave reflections at a distance. Such systems have been used since the 1960s to probe planetary surfaces, yielding information on their physical and electrical properties. Here we report the first successful uplink-geometry planetary bistatic radar observations. In 2005, the planet Mars was illuminated 56 times for 20 minutes each by an unmodulated 75-cm wavelength circularly polarized wave transmitted from the SRI International 46-m antenna in the Stanford foothills. The direct signal and a Martian surface echo, separated by differential Doppler frequency shifts, were received simultaneously by the one-bit receiver on board the Mars Odyssey orbiter. The surface echoes exhibit both fluctuating amplitude and varying spectral width, which are responses to surface reflectivity and roughness variations along the surface track. We analyze the echo data using quasi-specular scattering theory and exploit high-resolution Mars Orbiter Laser Altimeter topographic maps to better model the scattering surface in three dimensions at positions along the specular track of the echo. Assuming a two-scale classical scattering model, we infer surface roughness in the form of rms surface slopes. The results are important for evaluating landing safety for Mars exploration spacecraft, because the radar is sensitive to slopes on the order of a wavelength in size and larger. Most recently our results were used by NASA for the 2007 Phoenix Mars Lander landing site selection.
Moving Towards Full Renewability: The Potential Impacts of a Renewable Hydrogen Economy on California’s Water Resource
Keywords: Hydrogen as fuel
Sustainable energy
Water-supply > California
Water use > California
Thesis

California would be exposing its energy sector to drought risk and locked-in energy losses were it to make major investments in electrolysis-based hydrogen systems. Though a renewable electrolysis-based hydrogen economy could assure dispatchability and energy storage capacity while limiting harmful emissions, many of its benefits are associated with the challenge of patching renewable energy supply into the aging legacy of the current grid system. Faced with the opportunity to redesign energy delivery systems as the grid infrastructure comes to the end of its lifetime, California must recognize that an energy system fundamentally designed around hydrogen rather than electricity as the main energy carrier does not make sense. Not only are significant conversion losses associated with converting electricity into hydrogen and back, but electrolysis demands a substantial amount of very high quality water that is not realistically
available in California. Given California's high growth rate, threatened water supply. ecosystems, and delivery infrastructure, and demonstrated need to use scarce energy as efficiently as possible, the combined problems of high losses and water dependence that a hydrogen economy presents assure that long-term hydrogen-dependent infrastructural investments would be, at best, an inefficient use of resources.
Neutron scattering studies of the electron-doped high-temperature superconductor neodymium cerium copper oxide [electronic resource]
Keywords: Physics

While the mechanism for the high transition temperatures (Tc) in the cuprate superconductors remains unsolved, antiferromagnetic fluctuations on the copper-oxygen sheets are thought to play an important role. Long-range antiferromagnetic order is present in the undoped insulating parent compounds, whereas superconductivity is observed when these materials are doped with a sufficient number of holes or electrons. Because these two phases are well separated on the hole-doped side of the phase diagram, the interplay between antiferromagnetism and superconductivity is perhaps better studied in the electron-doped compounds, where the two phases appear to overlap. In this Thesis work, single crystals of electron-doped Nd{2-x}Ce{x}CuO4 (NCCO) were grown over a wide range of cerium concentration, and the following two neutron scattering studies were performed on these crystals. In the first study, an energy-integrating neutron scattering method is used to measure the two-dimensional instantaneous magnetic correlation length as a function of temperature and doping. For x < 0.12, the correlation length diverges at the same temperature at which magnetic Bragg peaks appear, as expected. For x > 0.12, on the other hand, the correlation length remains finite down to the lowest measured temperatures. Since bulk superconductivity is only found above about x=0.13, this shows that there is no genuine coexistence between superconductivity and long-range antiferromagnetic order, which was previously thought to extend to x = 0.17. The second study is the first inelastic neutron scattering investigation of an electron-doped cuprate superconductor in an applied magnetic field. This experiment measures how the weakening of superconductivity due to a magnetic field affects the antiferromagnetic response. An advantage of the electron-doped cuprates is that the critical field Hc2 required to completely suppress superconductivity is relatively low (~10 T). In zero field, the antiferromagnetic excitation spectrum of NCCO (x=0.166) is gapped below 2.5 meV. The gap energy is found to decrease linearly with applied field and to extrapolate to zero near Hc2. The observed behavior indicates that the non-superconducting ground state is similar to the (zero-field) paramagnetic state at temperatures above Tc, and thus that superconductivity and antiferromagnetism are not competing orders in this part of the phase diagram.
Novel targets within the Hepatitis C Virus nonstructural protein NS4B and their inhibition using distinct classes of small molecules [electronic resource]
Keywords: Microbiology and Immunology.

Hepatitis C Virus (HCV) is the causative agent of significant liver disease, including cirrhosis and hepatocellular carcinoma. This virus infects greater than 2% of the world's population, and treatment options for these patients are limited; thus, this virus represents a major public health problem. In this thesis, we aim to enhance our ability to solve this problem by unraveling the role that NS4B, one of the HCV nonstructural proteins, plays in the viral life cycle. Drawing on similarities to other plus-sense RNA viruses, we identify an RNA binding activity in NS4B, demonstrate that this activity is specific for the 3' terminus of the HCV genome template, and characterize the domains of NS4B that are responsible for this activity. We utilize microfluidic technology to perform a high-throughput screen for small molecule inhibitors of this RNA binding activity and identify clemizole hydrochloride, among others, as an effective inhibitor, both in vitro and in cell culture. Genetic analysis reveals mutations in NS4B than confer resistance to clemizole, as well as mutations in NS3 that suppress the genetic disruption of NS4B's RNA-binding domain. In addition to clemizole, our work identifies a small molecule inhibitor of HCV that affects a different activity of NS4B, its ability to form membrane-associated foci. We provide genetic, biochemical, and cell biological evidence that NS4B is the target of this drug, and an in vitro light scattering assay further suggests that it is the second amphipathic helix of NS4B that is the target. In total, our results demonstrate that two different activities of NS4B are each a valid pharmacological target for HCV antivirals and uncover two candidate compounds that have potential for further pharmaceutical development.
Organization Culture and Student Performance in California Charter Schools
Keywords:  Department of Economics
Stanford Department of Economics
administration
operational features
secondary school
audit
test scores
assessment.
Thesis

To understand the value of charter school autonomy and the consequential empowerment of school level educators, one must first understand the relationship between school administrative structure and student performance. Researchers have found organizational culture affects sales growth and market share growth in companies, but the effect on student performance has not been studied (Yilmaz and Ergun, 2008). To collect organizational culture information I sent a survey to every California charter school with at least one grade of high school age students. Using California Standards Test data I found a significant relationship between school management structure and student performance. Most notably, schools with comparatively more authoritarian leadership perform better, schools at which a school board of directors and principal are most empowered perform better, and schools at which state and school district level bodies are most empowered perform worse.
Plants, People, and Propithecus edwarsi: The Ecological, Social, and Economic Intersection of Conservation in Madagascar's Tropical Forests
Keywords:  Earth Systems Program
School of Earth Energy &amp; Environmental Sciences
lemurs
forest conservation
Thesis

The endemic primates of Madagascar, lemurs, rely heavily on fruit and young foliage in the forest for adequate nourishment and sustenance. During less-than-optimal conditions provoked by seasonal changes or habitat destruction, the lemurs may turn to non-tree plants as alternative food sources. This study surveyed common fallback food items of one lemur species, the Milne-Edward's sifaka (Propithecus edwardsi) in both disturbed and pristine habitats, in order to determine if the environment can accommodate a shift in diet to less desirable epiphytes and vines.
Political Economy Analysis of Income Distribution
Keywords:  Department of Economics
Stanford Department of Economics
political economy
relative income
voting
Thesis

To the extent of my knowledge, this paper is the first attempt to subject relative income under political economy analysis. The paper will introduce a utility function that includes relative income which will drives our models. According to the model, income distribution will coincide with wage distribution under specific assumptions. An intervention in income distribution may help agents to consume leisure but may effect the performance of the economy. When voters are facing the voting choice between equal and unequal policy, there are several parameters that may affect the voting outcome. For every unequal policy, there is an equal policy that is prefered by majority of voters and welfare improving and vice versa for every equal policy. However, not all policy that pass the vote is welfare improving and not all welfare improving policy will pass the vote. Then, we analyze the effect of income tax. Tax decreases the gap between the riches and the poorest, resulting in higher relative standing for almost all agents. The tax scheme we analyze will make all voters who receive redistribution and some net tax payers better off. Income tax that keeps economic efficiency and decreases income gap is welfare-improving.
Price Dynamics in Virtual World Auctions
Keywords:  Department of Economics
Stanford Department of Economics
virtual worlds
World of Warcraft
virtual currency auctions
eBay
Thesis

Virtual worlds like World of Warcraft and Second Life are slowly becoming recognized by researchers as ideal testing grounds for their theories. The unprecedented control over the world’s dynamics and the easy access to its data make them ideal for observation and controlled experiments. Do results from these worlds, however, have bearing on the physical world? While the agents in these worlds are indeed controlled by humans, the characteristics of these worlds differ from the physical world in many ways, not the least of which is in physics. One way to begin to answer this question is to analyze the behavior of bidders and sellers in virtual currency auctions. Specifically, this paper examines auctions in World of Warcraft and argues that buyers and sellers both value the game’s currency and price items consistently. The paper then briefly explains why the auction mechanism differs from eBay’s enough to render useless the techniques employed to analyze eBay auctions, and it concludes with a justification of why researchers should pay more attention to virtual worlds.
Probing RNA folding through electrostatic and coarse-grained simulations [electronic resource]
Keywords: Applied Physics

The discovery by Cech and coworkers that structured RNA molecules could catalyze specific reactions has revolutionized our understanding of RNA's role and place in the biological machinery of life. The notion of understanding RNA folding from a biophysical perspective means understanding the formation of RNA structure in terms of the basic physical forces at play. This thesis describes the the use of electrostatic and coarse grain simulations and associated experiments to investigate different features of RNA folding. Chapter 1 gives an brief introduction to RNA folding, the primary physical forces that influence its formation, and a review of recent advances in our understanding of structure formation in RNA. Chapters 2 and 3 comprise the next section of the thesis and detail advances in our understanding of electrostatic effects around nucleic acids, a topic of great importance in RNA folding. Specifically, chapter 2 presents the development of a size-modified Poisson-Boltzmann theory to help account for the effects of ionic size while chapter 3 presents a critical assessment of the Poisson-Boltzmann description of electrostatic relaxation in tethered duplex model systems. Chapter 4 highlights a general theoretical framework for understanding the combined effects of electrostatics and junction topology on RNA folding stability and specificity. The last section focuses on the use of coarse grained simulation to understand the role of junction topology in shaping the allowed conformational space of the Transactivation Response (TAR) element from the genome of the Human Immunodeficiency Virus (HIV). Though the last section is not, strictly speaking, a study of RNA folding, understanding RNA conformational motion is of critical importance to the question of structure acquisition in RNAs.
Purification of a promoter-specific and activator-dependent nucleosome disassembly factor [electronic resource]
Keywords: Biophysics.

The disassembly of promoter nucleosomes is a requirement for the activation of eukaryotic genes. It renders the DNA accessible to the transcriptional machinery and primes it for the synthesis of messenger RNA by RNA Polymerase II. Promoter selection is achieved by the activator, a sequence-specific DNA binding protein that recognizes the promoter and recruits the nucleosome disassembly factor. The goals of this project were: 1. To establish an assay that recapitulates promoter-specific and activator-dependent nucleosome disassembly in vitro as it has been observed in vivo. 2. To identify the nucleosome disassembly factor responsible for this activity by purifying it from fractionated crude yeast extract and testing individual fractions using the aforementioned assay. As a model system, I chose the PHO5 promoter from yeast. Its activator, Pho4, is shuttled into the nucleus in response to phosphate starvation, where it binds to the promoter and triggers the disassembly of three nucleosomes. This process has been postulated to require an ATP-dependent nucleosome disassembly factor that is recruited via the activation domain of Pho4. Previous genetic and biochemical experiments have failed at revealing the identity of such a factor. I discovered that an activator-dependent nucleosome disassembly activity can be detected in vitro, that it depends on the activation domain of Pho4, and that it exhibits strong preference for the PHO5 promoter over its open-reading frame. As expected, the activity requires ATP. I developed a chromatographic fractionation protocol through which the activity was purified to a high degree of homogeneity. Mass spectrometry revealed the chromatin-remodeling complex Chd1 and the transcription elongation factor Sub1 to coelute with the activity. Purified Chd1 exhibited nucleosome disassembly activity and a chd1 deletion strain constitutively activated at PHO5 lacked expression of PHO5. These results pave the way for a further characterization of Chd1 in promoter-specific nucleosome disassembly and for the quest for additional stimulatory factors involved in this fundamental biochemical process.
Pursuing the good life [electronic resource] : an examination of purpose, meaningful engagement, and psychological well-being in emerging adulthood
Keywords: Education.

Emerging adulthood represents a critical phase for the development of purpose in life, yet little is known about the process through which young people become purposeful, or what the lasting benefits of such purposefulness might be. The present investigation explored four primary hypotheses though three interconnected studies. The first hypothesis, addressed in Study 1 using cross-sectional data, posited that purpose and meaningful engagement would be associated with psychological well-being. The second hypothesis proposed a mediational model, wherein the relationship between meaningful engagement and psychological well-being would be mediated by purpose; this hypothesis was tested first with cross-sectional data in Study 1 and again using longitudinal data in Study 2. Third, a moderation hypothesis was tested on the temporal relationship between purpose and psychological well-being, specifically that the relationship would be stronger for those high in self-transcendent life goals. Finally, Study 3 tested an intervention hypothesis to see whether engaging in deep reflection on and discussion about one's life goals can increase purpose and, consequently, psychological well-being. The results showed partial confirmation of the hypotheses. The cross-sectional analyses showed strong relations among meaningful engagement, purpose, and psychological well-being, and provided support for the proposed mediational model. However, the longitudinal analyses did not show significant relations among the constructs. The moderation hypothesis provided evidence that the path from purpose to well-being was stronger for those high on self-transcendent life goals, suggesting psychological benefits of pursuing purposes beyond oneself (but not self-oriented life goals). Finally, there was a significant positive effect of engaging in deep discussion and reflection on one's life goals, toward both increased purpose and increased psychological well-being. Implications of these findings for higher education in particular are discussed, and directions for future research are presented.