Provisioning of the Inka army in wartime: obsidian procurement in Pambamarca,Ecuador

Ninety-nine obsidian artifacts from fortified and non-fortified sites in the Pambamarca region of northern Ecuador were analyzed with XRF to examine patterns of procurement of obsidian by soldiers in the Inka army and by the local Cayambes who were resisting Inka conquest. The results show that the Inkas acquired material from several different sources, a pattern consistent with provisioning by subject peoples in partial fulfillment of labor obligations. The Cayambes also acquired material from multiple sources, although they may not have directly procured material from all of the sources because the external boundary of Inka territory bisected the region of obsidian sources. That frontier may have prevented the Inkas from accessing one source, Callejones, from which the Cayambes acquired some of their obsidian. In addition, the Inkas were acquiring some obsidian from the Yanaurco-Quiscatola source, which had been previously abandoned around AD 1000.     

Zoning,More Than Just a Tool: Explaining Houston's Regulatory Practice

The intent of this article is to understand why Houstonians reject zoning while simultaneously adopting a collection of mechanisms that serve zoning-type functions. The answer is found in discursive-institutionalist approaches that emphasize the symbolic meaning (besides the instrumental value) that people give to regulatory tools. Zoning as a label is generally associated with an interference with individual liberty. Apparently, the other interventionist instruments do not carry the same negative value, which makes it possible to implement them without much opposition. Discourses shape institutions, like planning regulations, and we need to unravel and to understand these processes in order to increase the performance of planning.     

Spatial Point Processes Applied to the Distribution of River Junctions

The notion of randomness has been extensively applied to topological (nondimensional) properties of drainage networks. The spatial (dimensional) organization of five fluvial hierarchies is examined herein through the application of quadrat analysis to random and clustered spatial probability models. The Poisson, Polya-Aeppli, and negative binomial models are compared with point-pattern distributions of river junction location for three basins in Indiana and two fossil systems on an erosion surface in semiarid Australia. The negative binomial model best fits all five networks, suggesting that the branching behavior of fluvial systems follows the mathematical precepts leading to clusteredness of junctions. The degree to which the Polya-Aeppli model fits the data suggests the imposition of a temporally limited set of environmental conditions optimally suited for network growth. Only for the two fossil systems does the Poisson model agree. It is speculated that the effect of prolonged subaerial erosion may be to shift a clustered distribution towards the random state as the surface approaches a pediplained state.