Using the theory of potential games, this paper addresses the emergence of polycentric structures in cities, resulting from trade-offs between agglomeration economies and congestion effects. We consider a model that explains the formation of multiple business centers in cities as an equilibrium outcome under the presence of households' commuting costs and positive technological externalities between firms. We first show that the model is a large-population (non-atomic) potential game. To elucidate properties of stable spatial equilibria in the model, we consider local and global maximizations of the potential function of the model, which are known to correspond to various equilibrium refinement criteria. We find that (i) the formation of business centers (agglomeration of firms) is possible only when households' commuting costs are sufficiently low and that (ii) the size (number) of business centers increases (decreases) monotonically as communication between firms becomes easier.

Harris and Wilson (1978)'s retail location model is one of the pioneering works in regional sciences on the combination of the "fast" and "slow" dynamic describing spatial pattern formation processes in the economic landscape, which is a current well-established modeling technique. Although proposed some time ago, the comparative static (bifurcation) properties of the model have not yet been sufficiently explored. We employ a simple analytical approach developed by Akamatsu et al. (2012) to reveal previously unknown bifurcation properties of the model in a space with a large number of locations. It is analytically shown that the evolutionary path of spatial structure exhibits a remarkable property, namely "spatial perioddoubling cascade," which we cannot observe in the popular two-location setup. We also discuss strong linkages between the model and the models of "new economic geography" regarding the modeling strategies and their bifurcation properties.

In this study, we analyzed the actual amount of gasoline transported into the Tohoku region during the first month after the Great East Japan Earthquake. We found that: (1) the amount of gasoline supplied in the Tohoku region during the first two weeks was only 1/3 of the normal demand; (2) the shortage of supply in the first two weeks led to a huge "back-log of demand"; (3) it took four weeks for the backlog to be cleared and the lost (suppressed) demand during the period was equivalent to the amount of normal demand for 7 days; (4) the gaps between gasoline supply and demand in the Pacific coast areas were huge, compared with those in the Japan sea coast areas, while the gap in each prefecture of the Tohoku region was gradually reduced over time in the following order: Akita, Aomori, Iwate, Yamagata, and finally, Miyagi prefecture.

No abstract

The fifth wave of the coronavirus disease 2019 (COVID-19) pandemic caused by delta variant infection depleted medical resources, and the Japanese government announced glucocorticoid use for outpatients. An appropriate outpatient-glucocorticoid treatment for COVID-19 has not been established; therefore, we created treatment manuals with indications for glucocorticoid administration in a care facility adequately equipped to manage patients with mild to moderate COVID-19. Thirty-eight patients (24 males, 14 females; mean age 40.5 ± 11.8 years) were treated with glucocorticoids from August 1 to October 1, 2021 [COVID-19 staging, mild (n = 1), moderate I (n = 19), and moderate II (n = 18)]. Patients were treated with 6.6 mg/day d.i.v. or 6 mg/day p.o. dexamethasone, or 20-30 mg/day p.o. prednisolone. The median (25 th -75 th percentile) number of days from the date of onset to glucocorticoid administration was 8.0 days (7.0-11.25 days). While 24 patients were hospitalized, the condition of 14 improved without hospitalization. The median number of days from glucocorticoid administration to hospitalization was 1.0 day (range, 1.0-1.0 day). In the non-hospitalized patients, the median number of days of glucocorticoid administration was 5.0 days (5.0-5.25 days). The mean number of days from glucocorticoid administration to discharge from the care facility for non-hospitalized patients was 8.4 ± 3.3 days. The adverse reactions among non-hospitalized patients included insomnia (n = 1) and mild liver dysfunction (n = 3). The present method of glucocorticoid administration can be safely used for patients with COVID-19 in care facilities.