VictorJuiz/thesis huggingface dataset:
Exchange Rates and the Current Account Balance: A Case Study of the Yen
Keywords:  Department of Economics
Stanford Department of Economics
current account
trade
United States
Japan
exchange rate valuation
Thesis

Whenever there exists persistent current account imbalances between countries, the surplus country is often accused of undervaluing its exchange rate to give its exports an unfair advantage, and is thus pressured into letting its exchange rate appreciate. A forensic exploration of the embittered trade history between the United States and Japan is undertaken to refute these claims. This paper seeks to demonstrate that such an accusation is faulty. Firstly, such an accusation does not specify by which measure an exchange rate is undervalued. Secondly, even if an exchange rate is undervalued by a specified measure, it does not follow automatically that an undervalued exchange rate is a deliberate mercantilist policy that gives exports an unfair advantage. Thirdly, even if the exchange rate were allowed to appreciate, there is no evidence to suggest that the current account balance would be restored; a corollary to this is that any restoration of competitive balance need not be accompanied by a change in the exchange rates. Finally, the constant bashing of the surplus country introduces volatility into the system and leads could lead a ‘one-way bet’ on the exchange rate that makes it harder, rather easier, to achieve current account balance. In light of this, the United States should have worked together with Japan in the 1980s and 1990s to stabilize the yen-dollar exchange rate.
Exotic particles in topological insulators [electronic resource]
Keywords: Physics

Recently a new class of quantum state of matter, the time-reversal invariant topological insulators, have been theoretically proposed and experimentally discovered. These topological quantum states of matter are insulating in the bulk, but have gapless edge or surface states protected by the time-reversal symmetry. In particular, topological insulators in three dimensions are characterized by topological field theory which gives rise to the topological magnetoelectric effect, and is analogous to that describing the electromagnetism of the hypothetical particle called axion. In this thesis we will show that in these topologically nontrivial insulators, magnetic monopoles and axions, which are originally postulated in elementary particle physics, may emerge. Firstly we will show that when time-reversal symmetry is broken on the surface of a topological insulator, an electric charge near the surface will induce an image magnetic monopole. The composite particle consisting of an electron and its image monopole forms a dyon and obeys fractional statistics. Secondly, when there is an antiferromagnetic order in the bulk of a topological insulator, the magnetic fluctuations couple to the electromagnetic fields exactly like axions. The physical effect of the dynamical axion and its detection will also be discussed. Then finally we propose transition metal oxide of corundum structure as a candidate for topological magnetic insulators which can give rise to the dynamical axion.
Experimental studies of high-Tc cuprate superconductors with density wave correlations [electronic resource]
Keywords: Applied Physics

High-Tc cuprate superconductors remain the source of central intellectual challenges for condensed matter physicists two decades after their discovery. Accumulating evidence suggests possible ubiquity of coexisting superconducting and density wave correlations in the ground state of these materials. As both correlations in their spatiotemporally incoherent forms can in principle produce a pseudogap in the excitation spectrum, the nature of the pseudogap widely seen in cuprates above Tc comes to forefront of debate. I have been trying to address the relationship triangle between the pseudogap, superconductivity and density waves, by mainly using angle-resolved photoemission spectroscopy (ARPES) to study the momentum spaces of single-layer La-based (La214) and Bi-based (Bi2201) cuprates. In this thesis, I first talk about our ARPES-neutron scattering joint effort (in collaboration with Tohoku University) in the stripe-ordered state of La214. We found around the 1/8 doping level a dual nature of the pseudogap (in LBCO) and a dual nature of the spin stripe ordering ground state. The latter will be discussed in the context of a doping-dependent crossover between localized- and itinerant-spin ground-state physics, as demonstrated for the first time in a condensed matter system (1% Fe-doped LSCO). I then focus on our ARPES findings in both the pseudogap and superconducting states of nearly optimally-doped Pb-Bi2201 obtained over unprecedented momentum, energy and temperature ranges. They suggest that the pseudogap is a broken-symmetry state that is density-wave like and distinct from homogeneous superconductivity; it explicitly coexists with coherent superconductivity below Tc, causing a striking, momentum-dependent distortion of the high-Tc ground state. I also include in the appendix our recent observation of symmetry-distinct states (likely derived from the Cu dz orbital) in proximity to the Zhang-Rice singlet that has so far been generally taken as the only relevant electronic building block for cuprates. This finding might profoundly transform our upper-level understanding of high-Tc superconductivity as discussed above. This thesis ends with a chapter which describes my experimental philosophy, speculations and outlook for the near future of this field.
Explicitly minimizing clinical risk through closed-loop control of blood glucose in patients with type 1 Diabetes Mellitus [electronic resource]
Keywords: Aeronautics and Astronautics

Type 1 Diabetes Mellitus or Juvenile Onset Diabetes is currently a permanent, incurable disease that removes the ability of the patient's body to control blood glucose levels. This loss of automatic control greatly increases the patient's exposure to clinical risks of high and low blood glucose levels. These risks can be mitigated through tight, regulation of blood glucose levels using insulin injections, but only at the price of paying frequent attention to the blood glucose levels and manually providing accurate dosing decisions. This can be very trying for all patients, especially teenagers and children. Recent technological advances enable automatic external regulation of patient's blood glucose levels. Pumps can infuse insulin into the subcutaneous tissue to lower blood glucose levels. Continuous glucose monitors can sense subcutaneous glucose levels, specifically the rises caused by meals and the drops caused by insulin. This has caused a flurry of control and modeling research, in the hopes of mitigating the clinical risk without the price of constant human attention. The most common approach, and the one taken here, is to use model predictive control, where the predictions from a model of glucose dynamics are optimized against a cost function using the future insulin injections. We directly minimize the asymmetric clinical risk instead, and recognize that our control authority (the potential effects of injecting insulin) is largely limited to reducing the blood glucose level. We further consider likely future blood glucose measurements, since we both respond better to positive disturbances than negative ones, and because negative disturbances are more risky. Also, we explicitly estimate the uncertainty of predictions, since glucose dynamics incorporate uncertainty from the complex biology, stochastic patient behaviour, and extrapolation. More uncertainty should mean more cautious insulin injection. Lastly, since meals occur faster than insulin acts and can raise the blood glucose by 2 to 4 times the width of the acceptable range, this work develops a novel Bayesian framework for detecting meals and estimating their effects. This work improves prediction root mean squared error by 20% relative to predictions excluding meals for prediction horizons from 1 to 4 hours and improves robustness to meals. These prediction improvements alone reduce the avoidable clinical risk by 38% relative to predictions excluding meals. When the improvements to the predictions are combined with minimizing clinical risk under uncertainty and measurement anticipation the avoidable clinical risk is reduced by 30% relative to a published MPC controller that has privileged information and tunes independently for each patient.
Exploring Direct Sampling and Iterative Spatial Resampling in History Matching
Keywords:  Department of Energy Resources Engineering
School of Earth Energy &amp; Environmental Sciences
Thesis

We explore multiple methods to history match a porosity field by using both production data and a secondary data set. In this paper, seismic impedance is used as secondary data but any data set with identical dimensions as the primary data can be used. The task is formulated as an inverse problem where the production data is estimated through an upscaled ow simulator. Co-located permeability values are obtained though an empirical relationship from the well logs. The secondary seismic data is treated in two ways. Firstly, it is used as conditioning data to further constrain the porosity simulation. This means that the production data is the only data that has an objective/mist function. In the second method, porosity and seismic impedance are simulated simultaneously. This corresponds to an objective function with combined production and seismic data. If the second method is used, a more constrained porosity field is obtained in which channels follow the seismic more closely, whereas when the first method is used the channels are slightly thinner and more spread out. Because increased amount of conditioning data yields a more constrained a posteriori distribution it is likely that the optimization takes requires less steps to reach an optimum compared with the case where both seismic and production data is matched. In addition, frequency information is also incorporated into the objective function. However, because this information seems to conflict with the previous information, the convergence to an optimal point is decreased. This is a problem that could be mitigated with the right choice of the training image is the geospatial simulation.
Exploring the Yen Carry Trade: Investor’s Choice of Target Currencies
Keywords:  Department of Economics
Stanford Department of Economics
carry trade
unwinding
exchange rate
capital flow
interest differential
Thesis

Empirical studies have shown that carry trade plays an increasingly important role in driving exchange rate movements. Because carry trade can have an enormous impact on macroeconomic factors, understanding basic characteristics of carry trade will be useful for both researchers and policymakers in countries susceptible to carry trade speculations. Focusing on the yen carry trade, this paper seeks to determine what factors investors take into account when they choose target currencies. I accomplish this by estimating the relationship between carry trade volume and other economic and financial variables for nine selected countries in the Asia-Pacific region using a simple multiple regression model. I find that the interest rate differential and a country’s credit rating have statistically significant positive effects on carry trade volume while exchange rate movement does not affect the volume as strongly. The results also suggest that advanced economies are more prone to carry trade speculation, and therefore the risks of unwinding are greater in those countries.
The false consensus effect [electronic resource] : projection or conformity?
Keywords: Communication

The false consensus effect (FCE) is one of the most frequently cited phenomena in the social sciences and is widely presumed to illustrate how attitudes can shape perceptions. Yet, rarely have researchers directly tested this presumption. The purpose of this research is to address this gap in the literature. I begin with a review of the mechanisms presently thought to account for the FCE, formalizing them in causal diagrams that make explicit the mediational and moderational stories implicit in the explanations. Then, I describe what evidence exists for each of these explanations. And, finally, I report the results of four studies that tested the causal direction of the FCE. Study 1 manipulated participants' attitudes and found no impact of the resulting attitude change on perceptions of others' attitudes. Study 2 employed instrumental variable analysis to estimate the impact of participants' attitudes on their perceptions of others' attitudes and found no such impact. Study 3 tested an alternative explanation of the FCE: conformity to perceived social norms. Consistent with this claim, a manipulation of perceptions of others' attitudes influenced people's own attitudes. Applying covariance structure modeling to longitudinal data, Study 4 found evidence that perceptions of others' attitudes influence participants' own attitudes but no evidence that people's own attitudes shape perceptions of others' attitudes. Thus, instead of documenting attitude-distorted perceptions of others, the false consensus "effect" appears to result from one of the oldest social psychological phenomena in the literature: conformity to perceived social norms.
Fast neuroimaging techniques in MRI [electronic resource]
Keywords: Electrical Engineering

Magnetic Resonance Imaging (MRI) is a non-invasive modality for neuroimaging that has been widely applied into various clinical and scientific studies. In many applications, one particular challenge for MRI is the scanning speed and efficiency. Three major novel fast neuroimaging techniques are presented in this work, including high-resolution 3D diffusion imaging (3D-SNAILS), an iterative reconstruction algorithm for high accelerating parallel imaging (PRUNO), and motion insensitive 3D non-contrast perfusion imaging (3D-PCASL-PROMO). 3D DWI and DTI provide attractive features such as isotropic resolution, high SNR and good tractography. However, 3D volumetric DWI/DTI scans suffer from long scan time and severe motion artifacts. In this project, a steady-state multi-shot pulse sequence is demonstrated to perform fast high resolution 3D diffusion imaging, in which 3D self-navigated interleaved rotating spirals (3D-SNAILS) are used as readout trajectories. This acquisition scheme has low sensitivity to motion induced phase errors and the inherent navigators can be utilized to further reduce motion artifacts. In vivo human/animal results have shown that this technique can be used to perform 3D high resolution DTI studies, particularly for animals with smaller brains. GRAPPA has been a successful k-space data-driven reconstruction algorithm for parallel imaging during the last decade. However, the performance of GRAPPA drops significantly as the accelerating factor increases. A novel iterative method termed parallel reconstruction using null operations (PRUNO) is developed in this project. In this approach, both data calibration and image reconstruction are formulated into generalized linear system equations based on intrinsic small k-space nulling kernels. And a conjugate-gradient (CG) method is proposed to solve the reconstruction equation feasibly. With more accurate problem formulation and higher calibration efficiency, PRUNO produces much better image quality than GRAPPA, especially under high accelerating factors. Pulsed continuous arterial spin labeling (PCASL) is a novel technique for 3D whole-brain perfusion imaging. However, a whole brain clinical PCASL protocol takes long imaging time due to multiple image acquisitions and averages. A real-time motion correction algorithm is thus desired for such a protocol. Prospective motion correction (PROMO) is a navigator based module, which can be easily inserted into various MR pulse sequences for real-time 3D motion estimation and correction. PROMO is successfully integrated into PCASL in this project. Our preliminary results show that the new pulse sequence is much more robust against patient motions and PROMO navigators have almost no negative influence to the imaging sequence. In addition, brief abstracts of two other fast imaging projects are also demonstrated in this dissertation, including a fast T2* imaging pulse sequence called iESGRE, and 7T diffusion imaging of rats using SNAILS.
Feeling wronged leads to entitlement and selfishness [electronic resource]
Keywords: Psychology

Five studies demonstrate that feeling wronged leads to a sense of entitlement and to selfish behavior. In Study 1, participants who were instructed to recall a time when their lives were unfair were more likely to refuse to help the experimenter with a supplementary task than were participants who recalled a time when they were bored. In Study 2, the same manipulation increased intentions to engage in a number of selfish behaviors, and this effect was mediated by self-reported entitlement to obtain positive (and avoid negative) outcomes. In Study 3, participants who lost a computer game for an unfair reason (a glitch in the program) requested a more selfish money allocation for a future task than did participants who lost the game for a fair reason, and this effect was again mediated by entitlement. In Studies 4 and 5, bad luck from a fair, random system led to the same kinds of effects for men. In Study 4, students (especially men) who received bad numbers in a housing lottery expressed less intention to behave charitably. In Study 5, men who were assigned to bad outcomes by the roll of a die were less willing to help out by signing up for an additional experiment than were men in the control condition, and self-reported entitlement again mediated the effect.
Ferromagnetism and resisitive switching in magnesium oxide with nitrogen doping [electronic resource]
Keywords: Materials Science and Engineering

Over the past several years, there have been considerable interests in the possibility of creating ferromagnetism in thin films of doped oxide materials. Several systems have been identified to be ferromagnetic at room temperature but all of these systems contain either a transition metal element or a rare earth metal element as a dopant. Since in such systems the formation of second phase or clusters of magnetic ions cannot be ruled out, the origin of ferromagnetism is still controversial. Our interest is exploring the possibility of ferromagnetism existing in the oxide materials. We have chosen to study whether doping alkali earth metal oxides with nitrogen yields ferromagnetic oxides. There are several theoretical predictions that such systems will be ferromagnetic, yet there is no conclusive experimental demonstration of such a finding. In this dissertation, we demonstrate the ferromagnetism in the nitrogen-doped magnesium oxide where the N-dopant does not induce structural defects, where the N-dopant is not a metal, and where oxide is an insulator. We find that as-deposited N-doped MgO films are disordered and non-magnetic. These samples upon thermal annealing undergo a significant structural transformation with doped N atoms moving from interstitial/defect to substitutional sites within MgO lattice and the resulting films are ferromagnetic. The largest magnetic moment measured corresponds to 0.35 [mu]B/per N for the 2.2 at% N-doped MgO film. XPS data indicate the presence of an unpaired electron in 2p orbital of N. The long range spin-interaction of these unpaired N electrons mediated by the valence band of MgO is ferromagnetic. NEXAFS data support this conclusion as hole states are also observed in the O 2p state. These results for first time prove the authenticity of prior theoretical predictions about the possible ferromagnetism in N-doped alkali earth oxides. The second part of this dissertation is focused on the resistive switching in N-doped MgO for memory applications. Resistive switching in thin layers is demonstrated herein, in which the thin layer include MgO doped with a small amount of N. The resistance change ratio (RHigh/RLow) can be varied between 1-4 orders of magnitude by varying the N content with just a few percent. In addition, SET voltage can be systematically lowered by varying the N content of the layer. The resistive switching properties of the N-doped MgO structures have several other attractive features. In particular, resistive switching is demonstrated to occur by applying SET and RESET voltage pulses from 1-100 nsec in duration and to exhibit low RESET current (few tenths of [mu]A). Multi-level resistive switching is also demonstrated. These unique advantages of N-doped MgO are highly desirable for the next generation nonvolatile memory.
Ferruccio Busoni and the ontology of the musical work [electronic resource] : permutations and possibilities
Keywords: Music

Ferruccio Busoni's conception of the musical work derives from his multiple roles as performer, aesthetician, editor, composer, arranger, and intellectual. Drawing on unpublished scores, manuscripts, sketches and documents from the Staatsbibliothek in Berlin, concert programs from a private collection in Berkeley, acoustic recordings, information about Busoni's intellectual interests gleaned from an auction catalogue featuring the contents of his extensive library, and the published aesthetic writings, letters, and compositions, the present study offers the first comprehensive account of Busoni's work concept. By establishing connections between his ideas and his musical practice, it explores and clarifies the reasoning behind his idiosyncratic compositional style, a style characterized by a blurring of boundaries between original and borrowed material. Polystylistic mixtures of the old and new and a distinctive performance style, in which Busoni creatively altered and embellished existing texts, exemplify his practice in an age in thrall to Werktreue, when originality of idea was prized above all else.
First observation of the eta_b meson and study of the decays Upsilon(3S) -> gamma eta_b and Upsilon(2S) -> gamma eta_b [electronic resource]
Keywords: Physics

This dissertation presents the results of an analysis of data samples consisting of 122 million Upsilon(3S) decays and 90 million Upsilon(2S) decays collected with the BABAR detector operating at the PEP II asymmetric-energy storage rings at SLAC National Accelerator Laboratory. The eta_b meson is observed for the first time in the decay Upsilon(3S) -> gamma eta_b and its existence is confirmed in the decay Upsilon(2S) -> gamma eta_b. The eta_b mass extracted from the Upsilon(3S) -> gamma eta_b sample is 9388.9^{+3.1}_{-2.3}(stat) +/- 2.7 (syst) MeV/c^2, corresponding to a hyperfine mass splitting m_{Upsilon(1S)}-m_{eta_b}=71.4^{+2.3}_{-3.1}(stat) +/- 2.7(syst) MeV/c^2. The branching fraction for the decay Upsilon(3S) -> gamma eta_b is determined to be [4.8 +/- 0.5(stat) +/- 0.6(syst)] x 10^{-4}. An analysis of the decay Upsilon(2S) -> gamma eta_b confirms the observation of the eta_b meson and provides an additional measurement of the eta_b mass: 9394.2^{+4.8}_{-4.9}(stat) +/- 2.0 (syst) MeV/c^2. The branching fraction for the decay Upsilon(2S) -> gamma eta_b is determined to be [3.9 +/- 1.1(stat)^{+1.1}_{-0.9} (syst)] x 10^{-4}. As the measurements in the two samples are consistent, the masses are averaged to provide a combined value of m_{eta_b} = 9390.9 +/- 3.2 MeV/c^2. After canceling common systematic errors, the following branching fraction ratio is determined: BR[Upsilon(2S) -> gamma eta_b]/BR[Upsilon(3S) -> gamma eta_b] = 0.82 +/- 0.24(stat)^{+0.20}_{-0.19}(syst).