Employment and urban growth; an application of Czamanski's model to the Mexican case

The author applies the 1964 model developed by Stanislaw Czamanski, based on theories of urban growth and industrial localization, to the analysis of urban growth in Mexico. "The advantages of this model in its application as a support instrument in the process of urban planning when the information available is incomplete are...discussed...." Census data for 44 cities in Mexico are used. (SUMMARY IN ENG)     

Explaining migration: theory at the crossroads

The author presents the case that the study of migration over the past century has become too diverse. He reviews works by writers from the several disciplines covering the topic, then cites the need to develop a consistent classification of the types of migration and their origins using standardized terminology. (SUMMARY IN ENG)     

Metabolite sensitivity in the methaqualone radioimmunoassay.

Recent literature reflects the increased use of RIA as a qualitative and quantitative tool. This study exemplifies the problems that may arise when this technique is used for quantitation. Caution must be exercised, and a physiological and toxicological understanding of each particular drug is essential to provide credible results. It is evident that the sensitivity and ease of the RIA method for methaqualone makes it invaluable as a screening test, but confirmation and quantitation of this drug must remain with those methods that can quantitate each metabolite.