A NOTE ON THE STABILITY PROPERTY OF SPATIAL COMPETITION*

ABSTRACT. Our study extends the standard comparative static analysis to allow for dynamic aspects of equilibrium in spatial competiton. We investigate dynamic stability properties via the Routh-Hurwitz criterion. Nontrivial equilibria in the so-called Löschian, Hotelling-Smithies, and Greenhut-Ohta models are shown to be stable even under heterogeneous cost conditions among competing firms, conditions not considered hitherto. We can thus provide powerful support to the comparative static analyses which can only be developed via equilibrium concepts with stability properties.     

URBAN UNEMPLOYMENT AND THE SPATIAL STRUCTURE OF LABOR MARKETS: AN EXAMINATION OF THE “TODARO PARADOX” IN A SPATIAL CONTEXT*

ABSTRACT The Todaro paradox and the effects of job creation in urban areas will be re-examined in our spatial model in which the radius of the labor market is endogenously determined by the rational choices of workers. The travel cost of workers plays a crucial role in the choice between two different types of response, migration or commuting. By considering travel costs, we find that the Todaro paradox can be applied to developed, as well as developing, countries. Job creation in urban areas can produce a paradoxical increase in urban unemployment in developed countries, because the low marginal cost of travel will significantly increase the radius of the urban labor market and create new labor supply without migration.     

COMPETITIVE AND IMPERFECTLY COMPETITIVE LABOR MARKETS IN URBAN AREAS*

ABSTRACT. In this paper, I present a model incorporating two kinds of spatial labor markets: a centralized competitive market at the central business district (CBD) and dispersed local markets across economic space under imperfect competition. Wage differentials and the size of the two types of markets are endogenously determined by rational choices of workers as well as profit maximization of firms. Workers can exercise rational choices with respect to market places where they commute and supply their labor. In this model, I attempt, in effect, to integrate the Hotelling-type paradigm and the Samuelson-type paradigm in a consistent spatial setting.     

The emergence of food production in Neolithic Japan

Chestnuts and walnuts, both sun-loving plants, were the most important food resources for sedentary villagers in Japan throughout the Jomon (Neolithic) period. Though morphologically these nuts were wild types, ecologically they were symbiotic with man. Given this ecological relationship, the following interrelation of Jomon period subsistence may be proposed: lowland, waterside villages, a generalized subsistence tradition comprising fishing, hunting, gathering, and farming lasted until the end of the Jomon period (ca. 2300 B.P.). In the Central Honshu Highland, specialized farming villages dependent on chestnuts and walnuts appeared in the late stage of the Early Jomon period (ca. 5500 B.P.) as an adaptation of the former tradition to this highland environment which lacks significant fish resources.     

Do temporal size differences influence species identification of archaeological albatross remains when using modern reference samples?

Zooarchaeological remains have been identified to species, using identification criteria based on specific morphological variations among modern specimens. However, temporal size changes in bones, due to micro-evolution and/or phenotypic plasticity, could distort identification of archaeological remains according to these criteria. We developed species identification criteria for North Pacific albatrosses (Short-tailed, Laysan and Black-footed Albatrosses) using both mensural- and DNA-based analysis and actually identified many archaeological remains from a site using these criteria. Our mensural-based criteria could accurately discriminate the modern Short-tailed Albatross from modern Laysan and Black-footed Albatrosses and indicated that the archaeological remains included both Short-tailed and Laysan or Black-footed Albatrosses. DNA-based criteria, however, suggested that all remains were Short-tailed Albatross. The most plausible explanation for this inconsistency would be misidentification using mensural-based analysis, due to temporal size changes in bones or existence of birds from extinct population(s) or breeding region(s) with mensurally different bones from recent birds. This is the first study that suggests temporal size changes in bones may distort the species identification of archaeological remains according to modern size variations. Further studies are required to judge if this pattern is unusual or not.