Dr. Kiyoshi Matsubara (p)

This study focuses on Japanese firms having performed FDI into Poland, Czech Republic, and Hungary, all of which have been the gateway of FDI in Central and Eastern European countries. Firm-level data of Japanese companies operating in either of those three countries in the 1990s to early 2020s are examined. The main results are as follows. First, machinery industries and wholesale industries of those products have many affiliates in all of the three countries, although distributions of industries are different among them. Second, many wholesalers of machineries were established in the 1990s to 2010s, followed by manufacturers producing them in the 2000s and 2010s.

Ms Madoka Muroishi (p)

Declining fertility has become a persistent concern in many advanced economies, with particularly low birth rates observed in highly populated urban areas. While agglomeration economies generate productivity gains and expand consumption variety, they may simultaneously increase the opportunity cost of childrearing. This paper develops a two-region general equilibrium model with monopolistic competition to examine how childcare support policies affect regional fertility gaps under urban agglomeration.
The model incorporates a Dixit–Stiglitz framework with iceberg transport costs and endogenous firm entry. Households derive utility from homogeneous agricultural goods, differentiated manufactured goods, and the number of children. Childrearing requires time, creating a trade-off between labor supply and fertility. Government policy is modeled as a reduction in the time required per child, capturing childcare services such as daycare provision.

The analysis shows that fertility tends to be lower in larger regions due to higher effective opportunity costs of time, even when consumption variety is greater. However, a childcare-time-reducing policy implemented in the larger region increases fertility more strongly there than in smaller regions. As a result, regional fertility gaps can shrink. The mechanism operates through the interaction between real wage effects and time constraints.
The model further demonstrates that time-reduction policies may be more effective than direct income transfers in high-wage urban areas. These findings suggest that urban-targeted childcare support can serve not only as a pronatalist policy but also as a regional inequality mitigation tool.

Dr. Anne Otto (p), Prof. Dr. Johannes Koenig

In recent decades, the higher education system of most OECD countries is characterized by a dynamic increase in the number of foreign PhD students being among the highest qualified workers. In times of a shortage of highly qualified talent, retaining doctoral graduates in the university region is very important in order to generate returns on public investment in education (Geissler/Koenig 2021), and to benefit for innovative activity (Hunt, Gauthier-Loiselle, 2010) and for economic activity (Ackers 2005). While there is a great literature on skilled international migration, studies on labour market outcomes of foreign Postdocs in destination countries are rather scarce (Tani, 2022). Hence, this leaves unresolved the issue for national economic and innovation policies in how successfull foreign scientists are on the labour market and in which segments of the labour market benefit most. The aim of this study is to shed light on the group of stayers - Postdocs who continue their careers in the destination country. We compare the regional and sectoral mobilities of foreign and non-foreign Postdocs in Germany and discrepancies in their career outcomes during the early career phase. First, we explore the stay rates of foreign and non-foreign Postdocs in the granting university region when they secure the first position after the doctorate. Second, we compare the sectoral mobilities and career outcomes of both Postdoc groups during the early career phase (up to three years after the doctorate). The focus is on career pathways in the academic and private sector and a set of labour market outcomes is studied such as fixed-term contracts, salaries, working time, management position and educational job matching. This enables us to detect whether there are considerable discrepancies between foreign and non-foreign Postdocs when transitioning into the labour market after graduation and whether initial differences diminuish over time. In a third step, regression analyses are conducted to analyse to what extent these sectoral differences in employment outcomes are marked by variation across disciplines and early-career research productivity.

Dr. Tomohiro Iwamoto (p), Ms Madoka Muroishi

This study investigates inter-prefectural student migration associated with university enrollment in Japan using a modified gravity model. While the traditional gravity framework explains migration flows by population size and geographic distance, this research extends the model by incorporating higher education variables such as the number of universities, enrollment capacity, academic selectivity, and field composition. Using prefecture-level panel data, the analysis estimates how the spatial distribution of higher education opportunities affects youth mobility patterns.
In addition to the empirical analysis, the study develops a simple theoretical model in which students choose their destination region by comparing expected lifetime earnings and the costs of enrollment and migration. In this framework, the supply and quality of universities influence regional expected benefits and thus shape migration incentives. The theoretical structure provides microfoundations for the modified gravity specification.
The model further controls for regional economic conditions, including income levels, urban amenities, and labor market prospects, to distinguish educational pull factors from general economic attractiveness. Estimation is conducted using the Poisson pseudo-maximum likelihood (PPML) method to address zero flows and heteroskedasticity. The study aims to clarify how higher education infrastructure influences long-term demographic dynamics and regional inequality.

Dr. Kenji Kondoh (p), Dr. Takaaki Morimoto

Considering a small country with four industries where we assume the productivity of agriculture sector should be damaged by the smokestack construction activities, we examine the impact on trade, natural environment, wage gap, and economic welfare of policies to increase the number of foreign workers in the construction, agriculture, and nursing care sectors, each of which plays a different role in the economy. We find that if the urban-rural wage gap is small enough, under certain conditions, introducing additional foreign workers to the agriculture sector may cause positive effects on domestic economic welfare regardless of expanding urban-rural wage gap and a declining natural environment. While introducing foreign workers to the construction or nursing care sector will surely reduce domestic economic welfare. If the urban rural wage gap is large enough to encourage rural domestic workers to move to urban area, foreign workers’ introduction to any sector must reduce domestic economic welfare.