New Findings on Forecasting under Structural Breaks

This thesis contributes to the literature of forecasting under structural breaks. Following the framework of Inoue, Jin, and Rossi (2017), Chapter 1 develops two window selection methods to select the optimal estimation sample size in rolling regressions in the presence of structural breaks and the Monte-Carlo experiments show the proposed bootstrap method is very competitive against existing methods, which could be a useful tool for practitioners. Chapter 2 applies the window selection methods on forecasting exchange rates, where the forecasting devices beat the random walk benchmark in 7 out of 18 countries, but none of the devices or models perform consistently across countries. While the window selection methods could solve the ”Meese-Rogoff” puzzle in a few countries, the fixed rolling window is preferred in most cases. The findings also suggest Mark’s (1995) monetary model is the most promising model for exchange rate forecasting in the short horizon, rather than the Taylor rule fundamentals or PPP models. Chapter 3 provides strong evidence that parameter instability could result in forecast failure on linear models with a large set of Monte-Carlo experiments. It demonstrates that the linear forecasting models are more likely to fail when there are fewer observations available in the estimation sample, when making forecasts in the longer horizon, and when the external regressor is more volatile than the variable of interest. Moreover, the forecast failure is more likely to happen if the break date is closer to the forecasting date, if the variable of interest and the external regressor are both strongly autocorrelated, and if the parameter shift is negative instead of positive. Combining the findings in Chapter 2, it also implies that the flexible-price and sticky-rice monetary model could not be the true model of exchange rate movements. </div

Inflation forecasting with rolling windows: An appraisal

We examine the performance of rolling windows procedures in forecasting inflation. We implement rolling windows augmented Dickey–Fuller (ADF) tests and then conduct a set of Monte Carlo experiments under stylized forms of structural breaks. We find that as long as the nature of inflation is either stationary or non‐stationary, popular varying‐length window techniques provide little advantage in forecasting over a conventional fixed‐length window approach. However, we also find that varying‐length window techniques tend to outperform the fixed‐length window method under conditions involving a change in the inflation process from stationary to non‐stationary, and vice versa. Finally, we investigate methods that can provide early warnings of structural breaks, a situation for which the available rolling windows procedures are not well suited.</p

Synthesis and Structural Characterization of Homoleptic 1,2,4-Diazaphospholide Alkaline Earth Metal Complexes

The alkaline earth metal complexes [(η²-3,5-<i>t</i>Bu₂dp)­(μ-Mg)­(η¹:η¹-3,5-<i>t</i>Bu₂dp)]₂ (<b>2</b>), {[(η²-3,5-<i>t</i>Bu₂dp)­(μ-η²:η⁵-3,5-<i>t</i>Bu₂dp)­(μ-η²:η¹-3,5-<i>t</i>Bu₂dp)­Ca]₂(μ-Ca)} (<b>3</b>), [Sr­(3,5-<i>t</i>Bu₂dp)₂]_<i>m</i> (<b>4</b>), [Ba­(3,5-<i>t</i>Bu₂dp)₂)]_<i>n</i> (<b>5</b>), and [η¹-{H­(3,5-<i>t</i>Bu₂dp)}₂Ca­(η²-3,5-<i>t</i>Bu₂dp)₂] (<b>6</b>), bearing bulky 1,2,4-diazaphospholide ligands [3,5-<i>t</i>Bu₂dp]⁻ ([3,5-<i>t</i>Bu₂dp]⁻ = 3,5-di<i>-tert</i>-butyl-1,2,4-diazaphospholide), were prepared. The structures of magnesium and calcium 1,2,4-diazaphospholide complexes represent homoleptic 1,2,4-diazaphospholide alkaline earth metal oligomers with a novel array of metal–ligand binding modes

Measurement and Correlation of Solubility of Calcium‑l‑lactate Pentahydrate in Ethanol + Water and Acetone + Water Systems

The solubility of calcium-l-lactate pentahydrate (CLLP) in binary ethanol + water and acetone + water solvent mixtures was measured in the temperature range of 278.15 K to 313.15 K by using a synthetic method. The solubility of CLLP increases with increasing temperature, whereas it decreases with the increase of the initial mole fraction of ethanol or acetone. The solubility data were correlated by using the modified Apelblat equation, the CNIBS/R-K equation, and the hybrid model, respectively. It was found that the modified Apelblat equation could give better correlation results both in ethanol aqueous solutions and in acetone aqueous solutions. The dissolution enthalpy, entropy, and Gibbs energy change of dissolution of CLLP in these solvent mixtures were obtained by using the modified van’t Hoff equation

Quantifying Spillovers Among Regions

The standard procedure for quantifying spillover effects of changes in economic fundamentals among separate regions (or countries) is to link the regions through predetermined weights – for example through fixed weighted trade indices or fixed spatial weights based on geographical distance. We provide a method for quantifying spillover effects among the U.S., the euro area, and the U.K. using spatial weights that are determined endogenously. We specify a new spatially augmented VAR model and we introduce a Bayesian estimation technique to freely estimate and quantify spatial interactions. We are able to quantify the effects of shocks to economic fundamentals in the three regions considered without imposing a priori restrictions on the size and directions of the spillovers. To illustrate our technique, we quantify the spillover effects of a series of shocks, including the recent rises in inflation and money supply shocks, in each of the three regions under consideration on the other regions.</p

Determination and Correlation of Solubility of Cefradine Form I in Five Pure Solvents from (283.15 to 308.15) K

The solubility of cefradine form I in five pure solvents from (283.15 to 308.15) K was experimentally determined by using an equilibrium method. It was found that the solubility of cefradine form I in all tested solvents increased with the increase of temperature. Four thermodynamic models were used to correlate the experimental solubility data. The infinite-dilution activity coefficient and mixing properties including the mixing free Gibbs energy, enthalpy, and entropy of cefradine form I solution were also calculated by using the nonrandom two-liquid (NRTL) model. It was found that the correlated results by the van’t Hoff equation, the modified Apelblat equation, and the NRTL model agreed well with the experimental data

Modeling and Simulation of Thermodynamic Properties of l‑Alanyl‑l‑Glutamine in Different Solvents

The solubility of l-alanyl-l-glutamine (Ala-Gln) in pure water and ethanol–water mixed solvents was measured using a synthetic method from 283.15 to 313.15 K. Molecular dynamics simulation was carried out to explain the effect of ethanol content on the solubility of Ala-Gln. The radial distribution function was used to evaluate the interactions between solute molecules and solvent molecules. The solubility data was correlated by four thermodynamic models, including the hybrid model, Wilson model, NRTL model, and UNIQUAC model. It was found that the NRTL model could give better correlation results than the other models. The dissolution properties of Ala-Gln solutions, including the free Gibbs energy, the dissolution enthalpy, and the dissolution entropy, were calculated by using the modified van’t Hoff equation

Isolation Strategies and Transformation Behaviors of Spironolactone Forms

Spironolactone (SPI) is one kind of potassium-sparing diuretic, and two polymorphs (form I and form II) along with five solvates (methanol, ethanol, acetonitrile, ethyl acetate, and benzene) of SPI have been reported in the literature. However, no detailed information about the stability, solubility, and transformation behaviors of SPI forms has been reported. In this paper, two new forms of SPI, 1-propanol solvate and 2-propanol solvate, were found and characterized. The thermodynamic stability and solubility of form II and four alcohol solvates of SPI were investigated and determined. It was found that methanol solvate and ethanol solvate of SPI are relatively stable while 1-propanol solvate and 2-propanol solvate of SPI are metastable in corresponding solvents, and 1-propanol solvate and 2-propanol solvate of SPI would transform to form II in corresponding solvents. Furthermore, the transformation processes of 1-propanol solvate and 2-propanol solvate were in situ monitored by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and Raman spectroscopy and some offline tools such as microscopy and powder X-ray diffraction (PXRD). The reasons behind the transformation were explained by the enthalpy data of different solvates

Solubility and Thermodynamic Stability of the Enantiotropic Polymorphs of 2,3,5-Trimethyl-1,4-diacetoxybenzene

The solubility data of two polymorphs of 2,3,5-trimethyl-1,4-diacetoxybenzene (TMHQ-DA) in ethanol, 1-propanol, 2-propanol, and 1-butanol at various temperatures were experimentally measured using gravimetrical method and correlated by the modified Apelblat model and the van’t Hoff equation, respectively. Differential scanning calorimetry (DSC) and thermogravimetry (TG) analyses were performed to investigate the thermodynamic stability and the transition of the two forms of TMHQ-DA. An enantiotropic relationship was found between TMHQ-DA Form A and TMHQ-DA Form B, and the transition point between them was experimentally determined to be 314.50 ± 1 K. A thermodynamic model for estimation of the transition point was also derived, and the estimated results are satisfactorily consistent with the experimental values. Finally, the accuracy of the transition point obtained in this research was validated by the polymorphic transformation experiments monitored using Raman spectroscopy

Solubility of Cefotaxime Sodium in Ethanol + Water Mixtures under Acetic Acid Conditions

Aimed at exploring the influence of acetic acid on crystallization thermodynamics of cefotaxime sodium (CTX), the solubility of CTX in ethanol + water mixtures under acetic acid conditions at various temperatures are measured by a gravimetrical method. Different from the solubility curve when acetic acid is absent, the solubility curves of CTX under acetic acid conditions have a maximum value. The maximum solubility drifts as temperature varies, which is related to the dielectric constants of solvent mixtures. A combination of the Jouyban–Acree model and Apelblat equation is used to correlate the solubility data, and the correlation precision is improved when compared with that of the Jouyban–Acree model. By using the Wilson model, the activity coefficients of CTX and the mixing Gibbs free energies, enthalpies, and entropies of CTX solution are also predicted. The data presented in this study explain why the crystallization of CTX in ethanol + water mixtures is difficult and are helpful for guiding the industrial reaction and crystallization process of CTX