TRANSPORTATION RATES AND LOCATION OF THE FIRM: A COMPARATIVE STATIC ANALYSIS*

ABSTRACT This paper examines the role of the structure of transportation rates in the Weber-Moses triangle model. It shows that, in Zeigler's analysis, the appearance of the price elasticities of demand for inputs actually vanish by a simple application of the envelope theorem. Applying comparative statics analysis, we show when transportation rates are a function of quantity and distance, the assumptions that the production function is homogeneous of degree one and the transportation rates elasticities with respect to quantity and distance are constant are not sufficient to insure that the optimum location is independent of the level of output. This result is significantly different from that obtained by either Miller and Jensen or Zeigler.     

A dynamic model of regional population growth and decline

"This paper presents a two-sector dynamic model of regional population change. The model contains a migration equation, an earnings equation, and an amenity equation for each region. In the context of this model, migration is seen as a disequilibrium process through which the regional populations move towards equilibrium positions. Migration occurs when one region is perceived to be superior to the other on the basis of its earnings and amenity levels. Equilibrium is achieved when population movements between the regions eliminate any differences in their relative attractiveness. A comparative-static analysis of the model is presented to analyze the effects of policy changes and exogenous shocks on the distribution of population among the regions." The geographical focus is on the United States.     

Seleucia Pieria: an ancient harbour submitted to two successive uplifts

Historical sources ascribe the foundation of Seleucia (Seleukeia) Pieria to Seleucos I Nikator, shortly before the foundation of Antioch in the late 4th century BC. The Seleucia Pieria site seems however to have been inhabited earlier, perhaps from around 700 BC, possibly by a Greek population under an Assyrian ruler. The city became of considerable military importance during the wars between the Ptolemies and the Seleucids; it was occupied by the Romans in the 1st century BC, but had practically disappeared in the 6th century AD.
Geomorphological surveys in the area have revealed the existence of elevated marine notches and rims bioconstructed by vermetids, oysters and calcareous algae, which occasionally erode or intersect the archaeological sites, showing that two rapid land uplift movements, probably of seismic origin, took place during the late Holocene. The first movement, which occurred about 2500 ± 100 years bp, was the strongest one and caused a local vertical displacement of about 1.7 m, which may have severely affected the earlier Greek settlement. Though several earthquakes are reported to have occurred in the area during the following ten centuries, none of them seem to have been strong enough to cause significant vertical displacements. The second movement occurred around 1400 years bp, probably in May 526 AD, when a great earthquake followed by tsunami waves is known to have caused devastating damage in Antioch and Seleucia. According to geomorphological data supported by several radiocarbon dates, the earthquake was accompanied by a 0.7 to 0 8 m upheaval. This seismotectonic event also caused a rapid silting of the Seleucia Pieria closed harbour basin and entrances, thus preventing its further use.     

Evaluating Tobler's Migration Vector Fields

In the past decade Tobler has provided an innovative cartographic presentation of migration flows. The central theme of this research has been to utilize detailed migration data to reveal the underlying structures of migration flows. Even though the analyses are not explanatory models of migration exchanges, the application of these techniques to migration flows over time and across different spatial scales provides a visual generalization of often extremely complex flows. The application of his techniques at two spatial scales for the Netherlands illustrates both the strengths and weaknesses of migration force fields for the analysis of migration.