Essays in Automation and Globalization

This dissertation studies a range of topics in automation and globalization. Chapter 1 studies the role of industrial robots in the US in expanding the occupational wage polarization. Chapter 2 explores the effect of industrial robots in Japan on employment and wages in each industry and region. Chapter 3 investigates the impact of recent growth in multinational enterprises on headquarter country\u27s labor demand and labor share. Chapter 1 studies the distributional and aggregate effects of the rising use of industrial robots across occupations. I construct a novel dataset that tracks the cost of robots from Japan by occupations. The dataset reveals a relative one-standard deviation drop of Japan\u27s robot cost induces a 0.2-0.3¥% drop in the US occupational wages. I develop a general equilibrium model where robots are internationally traded durable goods that may substitute for labor differently across occupations. The elasticities of substitution between robots and labor within an occupation drive the occupation-specific real-wage effects of robotization. I estimate the model using the robot cost shock from my dataset and the optimal instrumental variable implied by the model. I find that the elasticities of substitution between robots and labor are heterogeneous across occupations, and higher than those between general capital goods and labor in production occupations such as welding. The estimated model implies that the industrial robots explain a 0.9 percentage point increase in the 90-50th percentile ratio of US occupational wages, and a 0.2 percentage point increase of the US real income from 1990 to 2007. Chapter 2 explores the impacts of industrial robots on employment in Japan, the country with the longest tradition of robot adoption. We employ a novel data set of robot shipments by destination industry and robot application (specified task) in quantity and unit values. These features allow us to use an identification strategy leveraging the heterogeneous application of robots across industries and heterogeneous price changes across applications. For example, the price drop of welding robots relative to assembling robots induced faster adoption of robots in the automobile industry, which intensively uses welding processes, than in the electric machine industry, which intensively uses assembling process. Our industrial-level and commuting zone-level analyses both indicate that the decline of robot prices increased the number of robots as well as employment, suggesting that robots and labor are grossly complementary in the production process. We compare our estimates with the ones reported by existing studies and propose a mechanism that explains apparent differences between the results. Chapter 3 investigates the impact of multinational enterprises (MNEs) on the source-country labor share. Our model shows that source-country factor demand elasticities with respect to foreign factor prices affect aggregate labor share. To identify these elasticities, we develop an estimator that leverages a foreign factor-productivity shock. We apply this estimator to a unique natural experiment: the 2011 Thailand Floods, which negatively impacted the foreign operation of Japanese MNEs. We employ a uniquely combined Japanese firm- and plant-level microdata and find that the Floods decreased fixed assets in Japan more than employment, suggesting that foreign factor productivity growth reduces Japan\u27s labor share

痕跡を生き直す : ゴーゴリの記号システムにおける反省の諸問題

学位の種別:課程博士University of Tokyo(東京大学

Electronic structures of B-2p and C-2p of boron-doped diamond film by soft X-ray absorption and emission spectroscopy

X-ray absorption (XAS) and emission (XES) spectroscopy near B-K and C-K edges have been performed on metallic (~1at%B, B-diamond) and semiconducting (~0.1at%B and N, BN-diamond) doped-diamond films. Both B-K XAS and XES spectra shows metallic partial density of state (PDOS) with the Fermi energy of 185.3 eV, and there is no apparent boron-concentration dependence in contrast to the different electric property. In C-K XAS spectrum of B-diamond, the impurity state ascribed to boron is clearly observed near the Fermi level. The Fermi energy is found to be almost same with the top of the valence band of non-doped diamond, E_V, 283.9 eV. C-K XAS of BN-diamond shows both the B-induced shallow level and N-induced deep-and-broad levels as the in-gap states, in which the shallow level is in good agreement with the activation energy (E_a=0.37 eV) estimated from the temperature dependence of the conductivity, namely the change in C-2p PDOS of impurity-induced metallization is directly observed. The electric property of this diamond is mainly ascribed to the electronic structure of C-2p near the Fermi level. The observed XES spectra are compared with the DVX-alpha cluster calculation. The DVX-alpha result supports the strong hybridization between B-2p and C-2p observed in XAS and XES spectra, and suggests that the small amount of borons (<1at%) in diamond occupy the substitutional site rather than interstitial site.Comment: submitted to Phys. Rev. B, 5 pages and 5 figure

Oxidative Stress Management in Chronic Liver Diseases and Hepatocellular Carcinoma

Chronic viral hepatitis B and C and non-alcoholic fatty liver disease (NAFLD) have been widely acknowledged to be the leading causes of liver cirrhosis and hepatocellular carcinoma. As anti-viral treatment progresses, the impact of NAFLD is increasing. NAFLD can coexist with chronic viral hepatitis and exacerbate its progression. Oxidative stress has been recognized as a chronic liver disease progression-related and cancer-initiating stress response. However, there are still many unresolved issues concerning oxidative stress, such as the correlation between the natural history of the disease and promising treatment protocols. Recent findings indicate that oxidative stress is also an anti-cancer response that is necessary to kill cancer cells. Oxidative stress might therefore be a cancer-initiating response that should be down regulated in the pre-cancerous stage in patients with risk factors for cancer, while it is an anti-cancer cell response that should not be down regulated in the post-cancerous stage, especially in patients using anti-cancer agents. Antioxidant nutrients should be administered carefully according to the patients' disease status. In this review, we will highlight these paradoxical effects of oxidative stress in chronic liver diseases, pre- and post-carcinogenesis

Effect of preterm birth on growth and cardiovascular disease risk at school age

Background.Low birth weight is associated with increased risk for cardiovascular disease (CVD) in later life. However, whether premature birth is also a risk factor for CVD has not been fully determined. The aim of this study was to investigate the relationship between gestational age and risk factors for CVD at school age. Methods. Using medical checkup data of school children, the relationship between gestational age and height, weight, body mass index, blood pressure, and lipid profiles at ages 9 and 12 years were investigated in children born preterm and admitted to neonatal intensive care unit at birth (n=182; 115 boys and 67 girls). These data were also compared between preterm small for gestational age (SGA) children and preterm appropriate for gestational age (AGA) children.Results.Gestational age was positively associated with height, and inversely associated with systolic blood pressure at school age. Preterm SGA children were significantly shorter and lighter at 9 and 12 years of age compared with preterm AGA children. However, there were no significant differences in any CVD risk factors between the groups.Conclusions.In preterm infants, a shorter duration of gestation is associated with higher systolic blood pressure at school age

Prediction of age and brachial-ankle pulse-wave velocity using ultra-wide-field pseudo-color images by deep learning

This study examined whether age and brachial-ankle pulse-wave velocity (baPWV) can be predicted with ultra-wide-field pseudo-color (UWPC) images using deep learning (DL). We examined 170 UWPC images of both eyes of 85 participants (40 men and 45 women, mean age: 57.5 ± 20.9 years). Three types of images were included (total, central, and peripheral) and analyzed by k-fold cross-validation (k = 5) using Visual Geometry Group-16. After bias was eliminated using the generalized linear mixed model, the standard regression coefficients (SRCs) between actual age and baPWV and predicted age and baPWV from the UWPC images by the neural network were calculated, and the prediction accuracies of the DL model for age and baPWV were examined. The SRC between actual age and predicted age by the neural network was 0.833 for all images, 0.818 for central images, and 0.649 for peripheral images (all P < 0.001) and between the actual baPWV and the predicted baPWV was 0.390 for total images, 0.419 for central images, and 0.312 for peripheral images (all P < 0.001). These results show the potential prediction capability of DL for age and vascular aging and could be useful for disease prevention and early treatment

Decreased Serum Antioxidant Marker is Predictive of Early Recurrence in the Same Segment after Radical Ablation for Hepatocellular Carcinoma

Radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) is a promising method for controlling tumors, although it does not entirely eliminate recurrence. Oxidative stress is associated with the progression of hepatocarcinogenesis, while also acting as an anticancer response. The objective of the present study was to investigate the factors influencing post-RFA outcomes. We recruited 235 newly diagnosed HCC patients who received RFA for single tumors. The patients with recurrence were sub-grouped into early and segmental recurrence groups. The characteristics of the sub-grouped patients were evaluated, including by measuring oxidative stress marker reactive oxygen metabolites and antioxidant marker OXY-adsorbent tests. The factors associated with poor survival were a high Child-Pugh score and early recurrence within 2 years in the same segment. The patients who experienced recurrence within 2 years in the same segment showed a larger tumor diameter than did others. According to a multivariate analysis, the OXY values were also significantly low in these patients. In conclusion, maintaining the antioxidant reservoir function with a high OXY value might be necessary to prevent early recurrence within the RFA-treated segment

Acute aortic dissection with sporadic aortic calcifications during chemotherapy with sunitinib

A 66-year-old man with imatinib-resistant metastatic liver tumors of gastrointestinal stromal tumor started chemotherapy with sunitinib. Baseline computed tomography showed sporadic aortic calcifications and liver tumors (A). His systolic blood pressure increased to 160 mm Hg during chemotherapy1 and decreased to 130 mm Hg with administration of antihypertensive medication. During his sixth cycle of chemotherapy, he developed an acute aortic dissection (AAD, Stanford A) with thrombosed false lumen of the ascending aorta despite good control of blood pressure and reduction of the liver tumors (B). The entry site of the AAD was already calcified before chemotherapy as in A

Predictive Factors for Successful Vaccination Against Hepatitis B Surface Antigen in Patients Who Have Undergone Orthotopic Liver Transplantation

Post-orthotopic liver transplantation (OLT) hepatitis B recurrence is well-controlled with a nucleos(t)ide analogue and hepatitis B immunoglobulin (HBIG) combination, but the high cost and the potential risk of unknown infection associated with HBIG remain unresolved issues. Low-cost recombinant hepatitis B virus (HBV) vaccine administration is a potential solution to these problems. We retrospectively analyzed the rate and predictive factors of HBV vaccine success in 49 post-OLT patients: liver cirrhosis-type B (LC-B), n=28 patients; acute liver failure-type B (ALF-B), n=8; and non-HBV-related end-stage liver disease (non-B ESLD) who received a liver from anti-hepatitis B core antibody-positive donors, n=13. A positive anti-hepatitis B surface antibody response was achieved in 29% (8/28) of the LC-B group, 88% (7/8) of the ALF-B group, and 44% (4/9) of the adult non-B ESLD group. All four non-B ESLD infants showed vaccine success. The predictive factors for a good response in LC-B were young age, marital donor, and high donor age. ALF-B and non-B ESLD infants are thus good vaccination candidates. LC-B patients with marital donors are also good candidates, perhaps because the donated liver maintains an efficient immune memory to HBV, as the donors had already been infected in adulthood and showed adequate anti-HBV immune responses