Location choices of firms and workers in an urban model with heterogeneities in skills and preferences

This paper investigates the location choices of firms and workers, and the implied commuting behavior, in a city comprising several jurisdictions. Jurisdictions are geographically represented by segments that are connected to each other at the center. Each jurisdiction has its own amenities. Workers are classified into types on the basis of their skills and amenity preferences. Firms employ all types of worker. A business area may be formed in the center or in the suburban segments. A monocentric configuration arises when the commuting cost is small and heterogeneity of workers is large.     

Debt covenants in Japanese loan markets: in comparison with the traditional relationship banking

This study investigates determinants of debt covenants in Japanese loan markets. We focus on a unique monitoring mechanism by Japanese banks and hypothesise that debt covenants substitute for the traditional main bank governance. Consistently, we find that debt covenants are less likely to be used for firms with stronger ties with their main banks. We also document that such use of debt covenants results in borrower’s upward earnings management. Overall, our evidence suggests that, in the Japanese context, debt covenants are used as a substitute for the main bank system yet they alone are an incomplete monitoring mechanism.     

一种新的粮食安全评价方法研究

该文提出了一个综合自然、社会和经济等多因子的粮食安全评价方法,选择了人均粮食占有量和人均GDP两个指标来描述粮食安全状况。人均粮食占有量的变化可以表述粮食供给性和稳定性变化状况,人均GDP变化则可以反映粮食可获取性和购买能力的变化,两者综合决定一个国家或地区的粮食安全状况。这两个指标分别和3个空间模型(空间EPIC模型、作物选择模型和IFPSIM模型)关联。利用该方法,以网格大小为6分弧度的地理单元为评价对象,以2000年为初始年份,对未来2020年的全球粮食安全状况进行了评价。研究表明,粮食供给短缺与贫困是危及粮食安全的最主要因素。到2020年,多数南亚国家和非洲国家,由于其人均粮食占有量和人均GDP两个指标值都显著降低,粮食供应不足和贫困一起将可能导致该区域存在粮食危机和饥饿风险。对于其它区域,日益增长的粮食需求可以通过本区域的粮食生产自给予以满足,或通过外部购买或粮食进口得到满足,总体上不存在粮食安全问题。     

Can Small Class Policy Close the Gap? An Empirical Analysis of Class Size Effects in Japan

Can smaller classes lead to better educational outcomes and greater equality in achievement? We estimate the causal effects of class size on achievement tests by using discontinuous changes in class size under the Japanese public compulsory education system. We employ a value‐added model that uses achievement tests conducted at two different times during the same school year. Our results show that a reduction in class size has significantly positive effects on Japanese language test scores in the sixth grade, especially at schools in wealthy areas. However, we find no evidence that a universal small class policy closes the achievement gap among schools.     

Bubbles,growth and imperfection of credit market in a two-country model

This study extends Hirano and Yanagawa (Rev Econ Stud 84(1):406–443, 2017) to an asymmetric two-country model and examines bubbles effects on each country’s long-run economic growth rate. This study also provides numerical examples with respect to the relationship between each country’s growth rate and their financial frictions in the balanced growth equilibria with bubbles and without bubbles. It shows that foreign bubbles have positive and negative effects on both countries’ growth rates, and which effect dominates depends on the level of financial development in both countries. In this study, the positive effect of bubbles tends to dominate when the total level of financial frictions in both countries is relatively low. When the total effect of bubbles on the growth rate is positive, the burst of foreign bubbles leads to a decrease in the growth rate in both countries. This implies that there is a positive correlation between foreign bubbles and the domestic as well as the foreign country’s growth rate.     

Within-group heterogeneity and civil war

This study offers a bargaining model of conflict in which the government offers a transfer to an opposition group to preclude civil war. Members of the opposition are heterogeneous in income and ideology, and heterogeneity generates disagreement about whether to accept the government’s offer. We assume that the probability that the government’s offer will preclude conflict increases continuously with the number of opposition group members who agree to accept it. When within-group heterogeneity is large, the number of members who are receptive to the government’s offer is less responsive to an increase in the transfer level. In this situation, the government must substantially increase its transfer to attract the support of the opposition. Subsequently, as peace becomes more costly for the government, negotiations are likely to break down.     

The system of towns with spatial public goods

In this paper, we introduce a model of ‘spatial public goods’, whose provision costs depend on the size of the benefit area. It is assumed that there are many developers providing spatial public goods in their towns. Each developer chooses the area size of his/her town and the quality of its spatial public good so as to maximize profit, taking the market price system as given. Each consumer chooses the level of the public good, and hence the town that supplies it, so as to maximize his/her utility. We show that the competitive equilibrium allocation of this economy is efficient.     

A New Computational Scheme for Computing Greeks by the Asymptotic Expansion Approach

We developed a new scheme for computing “Greeks” of derivatives by an asymptotic expansion approach. In particular, we derived analytical approximation formulae for Deltas and Vegas of plain vanilla and average European call options under general Markovian processes of underlying asset prices. Moreover, we introduced a new variance reduction method of Monte Carlo simulations based on the asymptotic expansion scheme. Finally, several numerical examples under CEV processes confirmed the validity of our method.     

The size distribution of ‘cities’ delineated with a network theory‐based method and mobile phone GPS data

We delineate “cities” independent of administrative boundaries in Japan by using a network theory‐based method and GPS‐based human mobility data. We divide the country into approximately 1 × 1 km² cells and detect the partition of cells that is optimal from the perspective of information theory. The resulting groups of cells are specified as cities. We find that the combination of two lognormal distributions better fits the city‐size distribution than a distribution with a Pareto upper tail. Moreover, we show that a jump diffusion process is the stochastic process of the city population underlying such a distribution.