No abstract

THERE IS WIDE AGREEMENT among anthropologists that a large, nucleated, sedentary population is a necessary condition for the development of complex society. A number of investigators have concerned themselves with the capacity of a given techno-environment to support a population of sufficient size t o permit higher socio-cultural forms t o evolve. South America has been an important testing ground for these ideas. Betty J. Meggers (1954) suggested a relationship between attained levels of cultural complexity and the agricultural potential of different regions of South America. In particular she argued that the thin, easily leached soils of the Amazon basin limited cultural development to a tribal stage (1954). In support of this assertion, Meggers cited the Marajoara culture which appeared to be intrusive in its lower Amazon island habitat (1957). She interpreted the sudden appearance and relatively rapid decline and disappearance of the Marajoara culture as indications that a relatively complex society with temples, class differences, and craft specialization could not sustain itself in the tropical forest.The scant demographic data available from Amazonia seem to support Meggers' assertions. Taken as a region Amazonia upon contact with Europeans is estimated to have had a population density no higher than l/km2 (Steward and Faron 1959:53), and even today the density is not much greater. The population of individual settlements (nucleated or not) is also small, judging from relatively recent data. Twenty-four of thirty Amazonian societies listed in the Ethnographic Atlas (Murdock 1967:227-231) have a mean settlement size of less than 100. Large settlements with nucleated populations of up to 1500 existed in the past, particularly along the main stream of the Amazon (Metraux 1945:698; Denevan 1966). Nevertheless, Meggers is apparently correct that most Amazonian settlements were quite small even before devastating European contact.Robert Carneiro (1961) challenged Meggers' 1954 views-which have since been considerably amplified and modified (Meggers 1971). Using data from the Kuikuru of Central Brazil and employing a formula he had derived to estimate the carrying capacity of swidden agriculture (Cameiro 1960), he suggested that the Kuikuru had the agricultural potential to maintain a sedentary village of up to 2000 with low labor inputs and without degrading the environment (but cf. Street 1969). He presented other evidence to show that tropical soils were, in some instances, capable of supporting densely settled populations.

The phantoms described in this work simulate the mechanical, optical, and acoustic properties of human skin tissues, vessel tissue, and blood. In this way, the phantoms are uniquely suited to serve as test models for multimodal imaging techniques and image-guided interventions.

No abstract

Simple exposure to Western goods may not be a sufficient explanation of why isolated village communities increase their participation in external market economies. The degree of market participation by four native villages in central Brazil is related to the difficulty of making a living from slash-and-burn subsistence agriculture as measured by the ratio of labor input to food output.