Purchasing Power Parity for Traded and Non-traded Goods: A Structural Error Correction Model Approach

When univariate methods are applied to real exchange rates, point estimates of autoregressive (AR) coefficients typically imply very slow rates of mean reversion. However, a recent study by Murray and Papell (2002) calculates confidence intervals for estimates of half-lives for long-horizon and post-1973 data, and concludes that univariate methods provide virtually no information regarding the size of the half lives. This paper estimates half-lives with a system method based on a structural error correction model for the nominal exchange rate, a domestic price index, a foreign price index, and a monetary variable. The method is applied to estimate half lives of real exchange rates based on producer price indices, consumer price indices, and GDP implicit deflators. The idea is that the traded component of the producer price index (PPI) is proportionately larger than that of the consumer price index (CPI). If the convergence rate is faster for traded goods prices than that for non-traded goods prices, half-lives for the real exchange rate based on the PPI should be shorter than those for the real exchange rate based on the CPI and that on the GDP implicit deflator. Our empirical results are consistent with this view.

Financial Development and Innovation-led Growth::Is Too Much Finance Better?

We show that the expansion of financial sector may hurt innovative activities and hence the innovation-led growth, using data on 50 countries over the 1990–2016 period. Countries with higher level of financial development are found to have a smaller positive or insignificant effect on innovation. The marginal effect of innovation on growth is a decreasing function of financial development. Using a dynamic panel threshold method we re-examine the possible non-linearity between finance, innovation and growth. We find that innovation exhibits an insignificant effect on output growth when credit to the private sector exceeds a threshold level of about 60% as a share of GDP. These results are not driven by banking crises, the long run effect of 2007–2008 financial crisis, or the ongoing European sovereign debt crisis

Long-Term Deflection Prediction from Computer Vision-Measured Data History for High-Speed Railway Bridges

Management of the vertical long-term deflection of a high-speed railway bridge is a crucial factor to guarantee traffic safety and passenger comfort. Therefore, there have been efforts to predict the vertical deflection of a railway bridge based on physics-based models representing various influential factors to vertical deflection such as concrete creep and shrinkage. However, it is not an easy task because the vertical deflection of a railway bridge generally involves several sources of uncertainty. This paper proposes a probabilistic method that employs a Gaussian process to construct a model to predict the vertical deflection of a railway bridge based on actual vision-based measurement and temperature. To deal with the sources of uncertainty which may cause prediction errors, a Gaussian process is modeled with multiple kernels and hyperparameters. Once the hyperparameters are identified through the Gaussian process regression using training data, the proposed method provides a 95% prediction interval as well as a predictive mean about the vertical deflection of the bridge. The proposed method is applied to an arch bridge under operation for high-speed trains in South Korea. The analysis results obtained from the proposed method show good agreement with the actual measurement data on the vertical deflection of the example bridge, and the prediction results can be utilized for decision-making on railway bridge maintenance

Development of polarizable methods for molecular mechanics simulations

University of Minnesota Ph.D. dissertation. January 2014. Major: Chemistry. Advisor: Jiali Gao. 1 computer file (PDF); xiv, 156 pages.This dissertation presents the development of two different types of polarization methods for molecular simulation methods, including Monte Carlo and molecular dynamics (MD) simulations. The first model, which is a polarizable intermolecular potential function (PIPF) method, is based on the point dipole method, where polarization energy is obtained from induced dipole moments and is added as correction to a force field. Hydrogen sulfide (H2S) molecule is studied and parameterized for the PIPF method, and this study displays that the PIPF method reproduces experimental gas-phase dipole moment, molecular polarizability, liquid density, and heat of vaporization very well with a relative error of less than 1.0%. Due to the over-polarization of the model, however, some liquid properties and liquid structure failed to reproduce experimental values, which indicates further improvement is necessary for the PIPF method. The second one is an explicit polarization (X-Pol) method, which is a self-consistent fragment-based electronic structure theory in which molecular orbitals are block-localized within fragments of a cluster, macromolecule, or condensed-phase system. The Lennard-Jone potential function is incorporated into the X-Pol potential in order to express short-range exchange repulsion and long-range dispersion interactions. The X-Pol potential is first developed at the B3LYP hybrid density functional with the 6-31G(d) basis set, and the Lennard-Jones parameters have been optimized on a dataset consisting of 105 hydrogen-bonded bimolecular complexes. It is shown that the X-Pol potential can be optimized to provide a good description of hydrogen bonding interactions; the root mean square deviation (RMSD) of the computed binding energies from CCSD(T)/aug-ccpVDZ results is 0.8 kcal/mol, and that of the calculated hydrogen bond distances is about 0.1 Å from B3LYP/aug-cc-pVDZ optimizations. In addition, the explicit polarization with three-point charge potential (XP3P) model is introduced using the polarized molecular orbital model for water (PMOw). The XP3P model is shown to be suitable for modeling both gas-phase clusters and liquid water, which is demonstrated from simulations of gas-phase water and protonated water clusters, and pure liquid consisting of 267 water molecules in a periodic system. This model is anticipated to be useful for simulating biological system in the condensed phase

On the Sign Problem in the Hirsch-Fye Algorithm for Impurity Problems

We show that there is no fermion sign problem in the Hirsch and Fye algorithm for the single-impurity Anderson model. Beyond the particle-hole symmetric case for which a simple proof exists, this has been known only empirically. Here we prove the nonexistence of a sign problem for the general case by showing that each spin trace for a given Ising configuration is separately positive. We further use this insight to analyze under what conditions orbitally degenerate Anderson models or the two-impurity Anderson model develop a sign.Comment: 2 pages, no figure; published versio

A Multi-level Algorithm for Quantum-impurity Models

A continuous-time path integral Quantum Monte Carlo method using the directed-loop algorithm is developed to simulate the Anderson single-impurity model in the occupation number basis. Although the method suffers from a sign problem at low temperatures, the new algorithm has many advantages over conventional algorithms. For example, the model can be easily simulated in the Kondo limit without time discretization errors. Further, many observables including the impurity susceptibility and a variety of fermionic observables can be calculated efficiently. Finally the new approach allows us to explore a general technique, called the multi-level algorithm, to solve the sign problem. We find that the multi-level algorithm is able to generate an exponentially large number of configurations with an effort that grows as a polynomial in inverse temperature such that configurations with a positive sign dominate over those with negative signs. Our algorithm can be easily generalized to other multi-impurity problems.Comment: 9 pages, 8 figure

Bosonic Field Methods for Unquenched Lattice QCD

Two new algorithms of particular interest in unquenched latticequantum chromodynamic simulations (lattice QCD) are studied: theall-point quark propagator algorithm for extracting full quarkpropagators, and the combined truncated determinant/multibosonalgorithm for simulating full dynamical QCD. In each case, a detailed study of the statistical properties andefficiency of the algorithm is made, allowing optimization ofthe relevant parameters, as well as an application of the algorithmto a problem of physical interest in lattice QCD. In the firstcase, the all-point method is applied to the problem of extractingparameters of the QCD chiral Lagrangian from lattice QCD measurementsof hadronic correlators. In the second case, the truncated determinant/multiboson method is used to search for a potential Sharpe-Singletonchiral phase in the strong-coupling region of unquenched QCD

In vivo Bioluminescent Imaging of Mammary Tumors Using IVIS Spectrum

4T1 mouse mammary tumor cells can be implanted sub-cutaneously in nu/nu mice to form palpable tumors in 15 to 20 days. This xenograft tumor model system is valuable for the pre-clinical in vivo evaluation of putative antitumor compounds

Molecular Recognition of Arginine by Supramolecular Complexation with Calixarene Crown Ether Based on Surface Plasmon Resonance

Arginine plays an important role in cell division and the functioning of the immune system. We describe a novel method by which arginine can be identified using an artificial monolayer based on surface plasmon resonance (SPR). The affinity of arginine binding its recognition molecular was compared to that of lysine. In fabrication of an arginine sensing interface, a calix[4]crown ether monolayer was anchored onto a gold surface and then characterized by Fourier Transform infrared reflection absorption spectroscopy, atomic force microscopy, and cyclic voltammetry. The interaction between arginine and its host compound was investigated by SPR. The calix[4]crown ether was found to assemble as a monolayer on the gold surface. Recognition of calix[4]crown monolayer was assessed by the selective binding of arginine. Modification of the SPR chip with the calix[4]crown monolayer provides a reliable and simple experimental platform for investigation of arginine under aqueous conditions