博士（経済学） / 甲第99号 / 155p / Hitotsubashi University

This dissertation consists of three essays investigating the historical roots of economic development and inequality in the US South. The first essay examines the impact of slavery on long-run development. Using county-level data from the US South, I show that slavery has impeded long-run development through the human capital channel. The mechanism involves labor market institutions and their impact on demand for human capital. I find that the history of slavery hindered integration of black workers into the labor market. Moreover, border-county analyses show that selective application of laws and regulations was a primary tool for impeding labor market integration. Through estimating the relative return to education for each county, I further argue that blacks in a region with a greater legacy of slavery had fewer incentives to invest in human capital. The second essay studies the long run effects of cotton agriculture focusing on a novel aspect of structural change. I show that cotton specialization in the late 19th century had long-run negative impact on local development, and the negative relationship became only evident in the second half of the 20th century. I argue that the change was caused by the mechanization of cotton production. After cotton mechanization, cotton labor with low human capital was relocated to local manufacturing. In response to the inflow of cotton labor, there was a decline in labor productivity in manufacturing which persisted through directed technical change. Using census data, I show that initial cotton specialization reduces demand for skills in manufacturing even to this day. The third essay addresses the legacy of cotton agriculture on economic inequality. Using the Gini index of household income, I show that initial cotton specialization increased long-run economic inequality at the county level. Moreover, evidence from the census data indicates that cotton specialization increased wage inequality exclusively in the local service sector, without any effects on the other non-agricultural sectors. As an explanation, I argue that wage inequality in the service sector increased due to expansion of employment in low-wage occupations followed by a decrease in their wage level.

Esta tesis se enmarca dentro de los efectos macroeconómicos que tiene el crecimiento de la productividad. En concreto, la tesis aborda tres grandes cuestiones; cómo afecta el crecimiento de la productividad al reparto de la renta nacional entre capital y trabajo; cómo afecta el crecimiento de la productividad de manera desigual entre sectores al crecimiento económico agregado; y cómo la actual pandemia del COVID-19 afecta de manera desigual a la renta nacional de las distintas regiones europeas. Las tres cuestiones tienen un denominador común central, el crecimiento de la productividad no es constante en el tiempo, entre sectores, ni entre regiones. El objetivo general de la tesis es comprender cómo el crecimiento varía a lo largo del tiempo, cómo el crecimiento de la productividad desigual entre sectores afecta a la composición de la economía; y cómo la propia composición de la economía implica asimetrías en los efectos de perturbaciones como las enfermedades infecciosas. En el primer capítulo de la tesis, intento responder por qué la proporción de rentas salariales sobre el PIB ha caído en Estados Unidos desde 1948. En un contexto en el que las empresas sustituyen capital por trabajo, una desaceleración de la productividad del trabajo llevará a las empresas a aumentar el ratio de capital-trabajo, lo que inducirá una caída de las rentas salariales sobre el PIB. Para que esta pueda ser la razón, dos cosas deben cumplirse, que el capital y el trabajo tengan cierto grado de sustitución y que la productividad del trabajo crezca a tasas cada vez menores. La principal parte del artículo se centra en estimar estos dos requisitos. En el segundo capítulo, me centro en una de las características principales del crecimiento moderno identificadas por Kuznets, cómo conforme las economías se desarrollan, la actividad económica se redistribuye de un sector a otro. En este capítulo, me centro en el caso de India. En India, la productividad del sector servicios ha sido la que más rápido ha crecido y esto ha provocado una tendencia creciente en la proporción del trabajo empleado en este sector. Además, durante el mismo tiempo, la proporción de la actividad económica en las manufacturas ha sido constante en el tiempo. En el capítulo, explico el proceso de transformación estructural desagregando los sectores de manufacturas y de servicios para explicar sus resultados agregados. Por último, en el tercer capítulo de la tesis co-autorado con Fidel Pérez Sebastián, estudiamos el impacto de la pandemia de COVID-19 para 109 regiones europeas y 10 sectores. La distribución de la actividad económica en las regiones europeas está lejos de ser simétrica, lo cual, en parte, se debe a que las productividades relativas de los sectores difieren entre regiones por lo que las consecuencias económicas de la pandemia no van a ser simétricas entre regiones. En este capítulo, nos centramos en cómo la evolución espacial de la pandemia puede ser explicada por las conexiones económicas entre regiones. Si dos regiones tienden a comerciar entre ellas, esto requiere que los individuos se trasladen de una región a otra y, por lo tanto, puedan transmitir el virus. Por otro lado, la pandemia tiene efectos asimétricos entre sectores ya que no todos los sectores tienen la misma capacidad de adaptarse al trabajo telemático ni a sustituir ciertos insumos intermedios.

Phenol formaldehyde (PF) is the oldest known synthetic polymer. This polymer has seen many applications throughout history, including jewelry, electric wire insulation, and resins used to make adhesives. Today, PF resins are still crucial components used in the wood products industry. These PF resins are formulated into adhesives used to make plywood and various other wood composite products. For example, in the United States, 90 % of the homes are still frame homes that use plywood for construction. The PF adhesives used to make these composites are formulated using agricultural waste products like walnut shells and corn-cob residue. These organic waste products act as fillers that reduce the cost, increase the viscosity, and affect the rheology of the fillers. Wheat flour is added as an extender to reduce cost and affect the tack of the adhesive. These organic fillers are lignocellulosic materials that are made of lignin, cellulose, and hemicellulose. Not much is known about the interactions of these organic fillers and the polymer resin. Rheological studies in our lab have shown that not all of the additions to the adhesive formulation are inert components in the adhesive. The steady-state flow curve analysis of PF adhesives revealed that there is a liquid structure change that occurs at high shear rate. This structure change is observed as a viscosity increase that occurs after applying a maximum shear rate of 4000 1/s. A rheological analysis was conducted to determine the source of this change, with individual components added to the resin. The PF base resin (with nothing added) has a Newtonian rheological behavior. When wheat flour is added to the resin, the overall viscosity increases, and shear thinning occurs at highe shear rates. There is no final viscosity change observed on with the addition of wheat flour. Adding corn-cob residue to the resin increased viscosity, led to some shear thinning at higher shear rates, and allowed the viscosity changes observed in the fully formulated adhesives. These experiments showed that the liquid structural changes that occur in the adhesives are attributed to the organic fillers. All organic fillers used in our studies, including corn-cob residue, walnut shell, almond shell, and Alder bark produce different levels of viscosity change in the PF adhesive formulations. These biomass materials have varying amounts of lignocellulosic content, particle size distributions, and particle shape. Among the fillers, corn-cob residue was shown to cause the most viscosity change compared to any of the fillers. Corn-cob residue is unique compared to the others because it has undergone acid digestion to convert its xylans to furfural. During the viscoelastic oscillation studies, the corn-cob residue filled adhesives showed that they developed network structures in response to a high shear rate that were not observed using the other fillers. With the discovery of these network structures, the next goal of this research was to correlate the effects observed on the rheometer to relevant adhesive application technology like high shear spraying. The corn-cob residue adhesive was sprayed at approximately 70,000 1/s compared to the 4000 1/s of rotational shear on the rheometer. The viscoelastic oscillation studies revealed that there was no network structure formation after high-shear spraying. Further, there was no change observed in the flow curve analysis after spraying the adhesive. This study showed that there are limitations when trying to correlate changes that happen in adhesives during spraying, where extensional forces dominate compared to shear forces. In future research, there is the opportunity to explore the effects of extensional deformation that occurs during the atomization of the adhesive, which will be more reflective of the changes that occur during spraying. / Doctor of Philosophy / Phenol-formaldehyde adhesives are crucial products in the home construction industry. These adhesives are used to make plywood that is used to build frame homes, which represent approximately 90 % of the homes in the United States. These phenol-formaldehyde adhesives are made using organic materials repurposed from agricultural waste products like corn cobs, walnut shells, almond shells, and tree bark. These products help to enhance the properties of the adhesive, reduce the cost, and reduce the amount of resin used. The goal of this research is to understand better the interactions between the adhesive and the organic fillers using rheology. Rheology is a field that studies how materials change and flow with applied external forces. This is an important field because it provides information on viscosity and viscoelastic behavior. Our research has shown that in response to high shear rates, the viscosity of these phenol-formaldehyde adhesives increases. Studying these changes can lead to a better understanding of how these materials change during industrial spraying. This understanding could lead to improved building adhesive materials in the home construction industry.

Row crop production can be characterized by constant change. Agricultural technology is responsible for most of the changes in productivity observed at the field level since the advent of mechanized farm equipment. Genetically modified (GM) cotton varieties have changed many aspects of cotton production in the United States. The advent of GM varieties has been the source of altered cropping practices in cotton production. The rapid adoption of GM cotton varieties in Mississippi has allowed producers to alter certain aspects of their farming operation because of added flexibility, increased yields, and other benefits of GM varieties. This study analyses the effects of certain changes in some of the most relevant components of cotton production on yield that stem from the adoption of GM varieties in Mississippi by estimating and comparing regional production functions from 1996 to 2005.

京都大学 / 新制・課程博士 / 博士(経済学) / 甲第23666号 / 経博第649号 / 新制||経||300(附属図書館) / 京都大学大学院経済学研究科経済学専攻 / (主査)教授 柴田 章久, 准教授 遊喜 一洋, 教授 佐々木 啓明 / 学位規則第4条第1項該当 / Doctor of Economics / Kyoto University / DGAM

This paper introduces ideas and methods for testing for structural change in linear regression models and presents how these have been realized in an R package called strucchange. It features tests from the generalized fluctuation test framework as well as from the F test (Chow test) framework. Extending standard significance tests it contains methods to fit, plot and test empirical fluctuation processes (like CUSUM, MOSUM and estimates-based processes) on the one hand and to compute, plot and test sequences of F statistics with the supF, aveF and expF test on the other. Thus, it makes powerful tools available to display information about structural changes in regression relationships and to assess their significance. Furthermore it is described how incoming data can be monitored online. / Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

In a recent article, Bai and Perron (2003, Journal of Applied Econometrics) present a comprehensive discussion of computational aspects of multiple structural change models along with several empirical examples. Here, we report on the results of a replication study using the R statistical software package. We are able to verify most of their findings; however, some confidence intervals associated with breakpoints cannot be reproduced. These confidence intervals require computation of the quantiles of a nonstandard distribution, the distribution of the argmax functional of a certain stochastic process. Interestingly, the difficulties appear to be due to numerical problems in GAUSS, the software package used by Bai and Perron. / Series: Research Report Series / Department of Statistics and Mathematics

In a recent article, Bai and Perron (2003, Journal of Applied Econometrics) present a comprehensive discussion of computational aspects of multiple structural change models along with several empirical examples. Here, we report on the results of a replication study using the R statistical software package. We are able to verify most of their findings; however, some confidence intervals associated with breakpoints cannot be reproduced. These confidence intervals require computation of the quantiles of a nonstandard distribution, the distribution of the argmax functional of a certain stochastic process. Interestingly, the difficulties appear to be due to numerical problems in GAUSS, the software package used by Bai and Perron. / Series: Research Report Series / Department of Statistics and Mathematics

A unified toolbox for testing, monitoring, and dating structural changes is provided for likelihood-based regression models. In particular, least-squares methods for dating breakpoints are extended to maximum likelihood estimation. The usefulness of all techniques is illustrated by assessing the stability of de facto exchange rate regimes. The toolbox is used for investigating the Chinese exchange rate regime after China gave up on a fixed exchange rate to the US dollar in 2005 and tracking the evolution of the Indian exchange rate regime since 1993. / Series: Research Report Series / Department of Statistics and Mathematics