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.     

Gender,households and reintegration: everyday lives of returned migrant women in rural northern Ghana

Since the late 1990s, migration of single women from the rural north to the urban south in Ghana has been making up a growing share of migrant streams. While the livelihood strategies of these migrant women in their southern destinations have been recently examined, the experience of reintegration for those who return to their place of origin has rarely been studied. Drawing on qualitative research with migrant women, returned migrant women (RMW) and their family members, this study examines everyday reintegration experiences of RMW within their households in a rural Dagomba community in Northern Region, Ghana. We conceptualise the household as an arena of everyday life wherein RMW exercise agency to learn to generate livelihoods that support their own as well as household members’ joint well-being. We combine this conceptualisation of household with feminist scholars’ recognition of gender as situated process. Our conceptualisation makes it possible to illuminate gender dynamics around the everyday repetitive decision-making acts that constitute livelihood generation as performed by RMW within specific intra-household dynamics in the context of reintegration in the situated community. Through the examination of the diverse and contradictory ways in which RMW exercise agency in making decisions about livelihood strategies within their households in the studied community, we show how the everyday repetitive acts of RMW contribute to micro-transformations of a situated gender ideology.     

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.     

A Reconsideration of the Construction Period of the Cruciform Terraces and the Elevated Causeways in the Angkor Monuments,Based on the Magnetic Susceptibility of the Sandstone Blocks*

In this paper, the construction period of the cruciform terraces with columns and the elevated causeways in the Angkor monuments of Cambodia is reconsidered, based on the results of our investigation of magnetic susceptibility and other characteristics of sandstone blocks. From an art‐historical point of view, they are generally considered as modifications in the post‐Bayon style period—the period during the reign of Jayavarman VIII (1243–95 ce ) or later. However, from a lithological point of view, the average magnetic susceptibilities of the sandstone blocks in the cruciform terraces with columns and the elevated causeways are consistent with the rest of the monument. In addition, the characteristics of the sandstone blocks in the cruciform terraces, such as their shape, the orientation of the bedding plane and the stacking method, suggest that they were constructed in the same period as the rest of the monument.     

Near-surface imaging of a buried foundation in the Western Desert,Egypt, using space-borne and ground penetrating radar

ALOS/PALSAR L-band full polarimetric data have been used to detect and characterize a well-defined geometric target hidden under sand deposits in the Western Desert of Egypt. This buried object is rectangular in shape with very straight boundaries and encloses an area of 500 m². Inside the rectangular area there is a perfectly circular feature of approximately 53 m² area. High and medium resolution optical satellite images (WorldView-2, ALOS/AVNIR-2) and field investigation confirm that the topography of the study area is relatively flat and completely covered by dry sand. The electromagnetic wave scattering behavior of the detected buried object was measured by decomposing the scattering matrix of ALOS/PALSAR full polarimetric data into Entropy-Alpha (H/α) and Freeman and Durden decompositions. Furthermore, a combination of unsupervised classification algorithms and Constant False-Alarm Rate (CFAR) edge detection was performed on the polarimetric data which revealed a well-defined geometric shape with straight borders. These borders have high α angles with low entropy, which physically means double bounce scattering mechanism with low randomness and is very similar to that of an urban scatterer, indicating that the detected target might be a buried wall-like foundation of a man-made structure. Moreover, 28 ground penetrating radar (GPR) profiles were acquired using a 270 MHz shielded antenna to validate the satellite radar remote sensing results. The GPR profiles reveal very clear hyperbolic shapes at 1.5 m depth with one of them showing a large hyperbolic shape-like structure, which might indicate the presence of a buried foundation. Thus the site might have significance to archaeological studies of the Western Desert, particularly previous human occupation and the sources of water for such habitation.     

Migration,Frictional Unemployment,and Welfare‐Improving Labor Policies*

Abstract. Studies have suggested that there exists job search and recruiting friction in urban areas. This paper constructs a two‐sector (rural and urban) model involving this factor and investigates how it affects migration and what the optimal policies should be. An analysis shows that frictional urban unemployment brings about intersector wage differentials and that an economy almost always has distortion in the absence of government intervention. Tax and subsidy policies that remove the distortion are explored. Setting urban wages appropriately is also shown to attain the optimum. Finally, we explore the criterion to judge whether changing urban wages as a policy, such as the minimum wage law, enhances social welfare.     

日本高等教育的现状和课题

我今天报告的题目是《日本高等教育的现状和课题》,我想从两个方面来谈。     

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.