Essays on International Capital Flows

This dissertation consists of three essays on international capital flows. The first chapter documents the accumulation of foreign exchange reserves and the simultaneous increase in the foreign direct investment (FDI) for emerging market economies. The second chapter discusses the performance of FDI firms and domestic firms in creating jobs using firm-level data from Orbis. The third chapter studies the proper exchange rate and monetary policy when emerging market economies denominate their external debt in foreign currencies. In Chapter 1, I study why emerging market economies hold high levels of foreign exchange reserves. I argue that foreign exchange reserves help emerging markets attract foreign direct investment. This incentive can play an important role when analyzing central banks' reserve accumulation. I study the interaction between foreign exchange reserves and foreign direct investment to explain the level of reserves using a small open economy model. The model puts the domestic entities and international investors in the same picture. The optimal level of the reserve-to-GDP ratio generated by the model is close to the level observed in East Asian economies. Additionally, the model generates positive co-movement between technology growth and the current account. This feature suggests that high technology growth corresponds to net capital outflow, because of the outflow of foreign exchange reserves in attracting the inflow of foreign direct investment, thus providing a rationale to the `allocation puzzle' in cross-economy comparisons. The model also generates positive co-movement between foreign exchange reserves and foreign debt, thus relating to the puzzle of why economies borrow and save simultaneously. In Chapter 2, joint work with Sakai Ando, we study whether FDI firms hire more employees than domestic firms for each dollar of assets. Using the Orbis database and its ownership structure information, we show that, in most economies, domestic firms tend to hire more employees per asset than FDI firms. The result remains robust across individual industries in the case study of the United Kingdom. The analysis shows that an ownership change itself (from domestic to foreign or vice versa) does not have an immediate impact on the employment per asset. This result suggests that different patterns of job creation seem to come from technological differences rather than from different ownership structures. In Chapter 3, I investigate how the devaluation of domestic currency imposes a contractionary effect on small open economies who have a significant amount of debt denominated in foreign currencies. Economists and policymakers express concern about the "Original Sin" situation in which most of the economies in the world cannot use their domestic currencies to borrow abroad. A devaluation will increase the foreign currency-denominated debt measured in the domestic currency, which will lead to contractions in the domestic economy. However, previous literature on currency denomination and exchange rate policy predicted limited or no contractionary effect of devaluation. In this paper, I present a new model to capture this contractionary devaluation effect with non-financial firms having foreign currency-denominated liabilities and domestic currency-denominated assets. When firms borrow from abroad and keep part of the asset in domestic cash or cash equivalents, the contractionary devaluation effect is exacerbated. The model can be used to discuss the performance of the economy in interest under exchange rate shocks and interest rate shocks. Future directions for empirically assessing the model and current literature are suggested. This assessment will thus provide policy guidance for economies with different levels of debt, especially foreign currency-denominated debt

Crowdsourcing Argumentation Structures in Chinese Hotel Reviews

Argumentation mining aims at automatically extracting the premises-claim discourse structures in natural language texts. There is a great demand for argumentation corpora for customer reviews. However, due to the controversial nature of the argumentation annotation task, there exist very few large-scale argumentation corpora for customer reviews. In this work, we novelly use the crowdsourcing technique to collect argumentation annotations in Chinese hotel reviews. As the first Chinese argumentation dataset, our corpus includes 4814 argument component annotations and 411 argument relation annotations, and its annotations qualities are comparable to some widely used argumentation corpora in other languages.Comment: 6 pages,3 figures,This article has been submitted to "The 2017 IEEE International Conference on Systems, Man, and Cybernetics (SMC2017)

Using Argument-based Features to Predict and Analyse Review Helpfulness

We study the helpful product reviews identification problem in this paper. We observe that the evidence-conclusion discourse relations, also known as arguments, often appear in product reviews, and we hypothesise that some argument-based features, e.g. the percentage of argumentative sentences, the evidences-conclusions ratios, are good indicators of helpful reviews. To validate this hypothesis, we manually annotate arguments in 110 hotel reviews, and investigate the effectiveness of several combinations of argument-based features. Experiments suggest that, when being used together with the argument-based features, the state-of-the-art baseline features can enjoy a performance boost (in terms of F1) of 11.01\% in average.Comment: 6 pages, EMNLP201

Using Argument-based Features to Predict and Analyse Review Helpfulness

We study the helpful product reviews identification problem in this paper. We observe that the evidence-conclusion discourse relations, also known as arguments, often appear in product reviews, and we hypothesise that some argument-based features, e.g. the percentage of argumentative sentences, the evidences-conclusions ratios, are good indicators of helpful reviews. To validate this hypothesis, we manually annotate arguments in 110 hotel reviews, and investigate the effectiveness of several combinations of argument-based features. Experiments suggest that, when being used together with the argument-based features, the state-of-the-art baseline features can enjoy a performance boost (in terms of F1) of 11.01\% in average.Comment: 6 pages, EMNLP201

Role of the TRPM4 channel in mitochondrial function, calcium release, and ROS generation in oxidative stress

Ischemic heart disease is one of the most common causes of death worldwide. Mitochondrial dysfunction, excessive reactive oxygen species (ROS) generation, and calcium (Ca2þ) overload are three key factors leading to myocardial death during ischemia-reperfusion (I/R) injury. Inhibition of TRPM4, a Ca2þ-activated nonselective cation channel, protects the rat heart from I/R injury, but the specific mechanism underlying this effect is unclear. In this study, we investigated the mechanism of cardioprotection against I/R injury via TRPM4 using hydrogen peroxide (H2O2), a major contributor to oxidative stress, as an I/R injury model. We knocked out the TRPM4 gene in the rat cardiomyocyte cell line H9c2 using CRISPR/Cas9. Upon H2O2 treatment, intracellular Ca2þ level and ROS production increased in wild type (WT) cells but not in TRPM4 knockout (TRPM4KO) cells. With this treatment, two indicators of mitochondrial function, mitochondrial membrane potential (DJm) and intracellular ATP levels, decreased inWT but not in TRPM4KO cells. Taken together, these findings suggest that blockade of the TRPM4 channel might protect the myocardium from oxidative stress by maintaining the mitochondrial membrane potential and intracellular ATP levels, possibly through preventing aberrant increases in intracellular Ca2þ and ROS

Production of TRPM4 knockout cell line using rat cardiomyocyte H9c2

The method presented in this article are related to the research article entitled as "Role of the TRPM4 channel in mitochondrial function, calcium release, and ROS generation in oxidative stress" [1]. TRPM4, a non-selective monovalent cation channel, is not only involved in the generation of the action potential in cardiomyocytes, but also thought to be a key molecule in the development of the ischemia-reperfusion injury of the brain and the heart [2-5]. However, existing pharmacological inhibitors for the TRPM4 channel have problems of non-specificity [6]. This article describes methods used for targeted genomic deletion in the rat cardiomyocyte H9c2 using the CRISPR-Cas9 genome editing system in order to suppress TRPM4 protein expression. Confocal microscopy, flow cytometry, Sanger sequencing, and western blotting are performed to confirm vector transfection and the subsequent knockout of the TRPM4 protein. These data provide information on the comprehensive analyses for knocking out the rat TRPM4 channel using CRISPR/Cas9. The analyses include confocal microscopy, flow cytometry, Sanger sequencing, and western blotting. This dataset will benefit biological and medical researchers studying the function of TRPM4-expressing cells including neurons, cardiomyocytes, and vascular endothelial cells. It is also useful to study the involvement of the TRPM4 channel in pathological processes such as cardiac arrhythmia and ischemia-reperfusion injury. The dataset can be used to guide the experiment of knocking out the TRPM4 gene and its subsequent application to the study of disease process caused by the gene

Treatment of Oxidative Stress with Exosomes in Myocardial Ischemia

A thrombus in a coronary artery causes ischemia, which eventually leads to myocardial infarction (MI) if not removed. However, removal generates reactive oxygen species (ROS), which causes ischemia-reperfusion (I/R) injury that damages the tissue and exacerbates the resulting MI. The mechanism of I/R injury is currently extensively understood. However, supplementation of exogenous antioxidants is ineffective against oxidative stress (OS). Enhancing the ability of endogenous antioxidants may be a more effective way to treat OS, and exosomes may play a role as targeted carriers. Exosomes are nanosized vesicles wrapped in biofilms which contain various complex RNAs and proteins. They are important intermediate carriers of intercellular communication and material exchange. In recent years, diagnosis and treatment with exosomes in cardiovascular diseases have gained considerable attention. Herein, we review the new findings of exosomes in the regulation of OS in coronary heart disease, discuss the possibility of exosomes as carriers for the targeted regulation of endogenous ROS generation, and compare the advantages of exosome therapy with those of stem-cell therapy. Finally, we explore several miRNAs found in exosomes against OS

Interpretable Math Word Problem Solution Generation Via Step-by-step Planning

Solutions to math word problems (MWPs) with step-by-step explanations are valuable, especially in education, to help students better comprehend problem-solving strategies. Most existing approaches only focus on obtaining the final correct answer. A few recent approaches leverage intermediate solution steps to improve final answer correctness but often cannot generate coherent steps with a clear solution strategy. Contrary to existing work, we focus on improving the correctness and coherence of the intermediate solutions steps. We propose a step-by-step planning approach for intermediate solution generation, which strategically plans the generation of the next solution step based on the MWP and the previous solution steps. Our approach first plans the next step by predicting the necessary math operation needed to proceed, given history steps, then generates the next step, token-by-token, by prompting a language model with the predicted math operation. Experiments on the GSM8K dataset demonstrate that our approach improves the accuracy and interpretability of the solution on both automatic metrics and human evaluation.Comment: Accepted to The 61st Annual Meeting of the Association for Computational Linguistics (ACL 2023

Systematic Understanding of Pathophysiological Mechanisms of Oxidative Stress-Related Conditions-Diabetes Mellitus, Cardiovascular Diseases, and Ischemia-Reperfusion Injury

Reactive oxygen species (ROS) plays a role in intracellular signal transduction under physiological conditions while also playing an essential role in diseases such as hypertension, ischemic heart disease, and diabetes, as well as in the process of aging. The influence of ROS has some influence on the frequent occurrence of cardiovascular diseases (CVD) in diabetic patients. In this review, we considered the pathophysiological relationship between diabetes and CVD from the perspective of ROS. In addition, considering organ damage due to ROS elevation during ischemia-reperfusion, we discussed heart and lung injuries. Furthermore, we have focused on the transient receptor potential (TRP) channels and L-type calcium channels as molecular targets for ROS in ROS-induced tissue damages and have discussed about the pathophysiological mechanism of the injury