Spatial Representations of Habitat in Competition‐Colonization Models

Ecological models with species differentiated by competition and colonization traits have shown that some extant species in remnants of habitat go extinct after a lag. These models have, however, analyzed landscape patterns in two phases: habitat and nonhabitat. Here, the consequences of representing landscape patterns as a continuous surface of habitat quality versus as two categories are examined. With a continuous representation, the amount of habitat is constant at 100 percent, but its quality can vary from 0 to 1; with a binary representation the amount of habitat varies. Continuous landscapes with mean habitat qualities of .8, .5, and .2 are compared to binary landscapes with the proportion of habitat at .8, .5, and .2. The model projections of the abundances of species differ substantially between the two‐phase and continuous representations. The effects of decreased habitat quality with no decrease in abundance exceed the effects of decreased habitat abundance. Differences between the projections for the two representations increase as the proportion of habitat and habitat quality decrease. Increases in the variance of habitat quality within the continuous representations decrease extinctions. The basic insight of earlier models, that superior competitors are at a long‐term disadvantage in remnant habitat, is magnified with a continuous representation. As in the binary models, the disadvantage is lessened if the spatial variation in habitat quality is smoother, but pattern matters less in continuous landscapes. The continuous representation shows that lagged extinction is relevant to cases of habitat deterioration.     

Rocks are heavy: transport costs and Paleoarchaic quarry behavior in the Great Basin

Central place foraging models are used to investigate assemblage variability at two Paleoarchaic (terminal Pleistocene/early Holocene) dacite quarries in the central and eastern Great Basin. Our analyses focus specifically on biface reduction and how varying degrees of reduction relate to the costs of transporting the resulting products upon departing the quarry. Our results suggest that when the distance to be traveled to a residential base is great, reduction will proceed further at the quarry than if the residential base is fairly close. Further, a residential site assemblage will consist of bifaces at later stages of reduction than its associated quarry.     

Two Value-pluralist Arguments for Liberalism

John Gray has argued that Berlinian value pluralism undermines the traditional claims of liberalism to universal authority, rendering it at best no more than one legitimate political form among others. That view is mistaken; value pluralism implies a distinctive case for liberalism as a universal project by way of two principal lines of argument. First, pluralism implies the desirability within a given political arena of a diversity of goods and ways of life, a diversity best accommodated by liberalism. Second, the rational resolution of particular cases of value conflict under pluralism is possible (where it is possible) only by way of a particularist, Aristotelian form of practical reasoning, which requires the exercise of certain characteristically liberal virtues. Overall, pluralism not only supports liberalism, but supports liberalism in a strong, universalist and perfectionist form.     

The Maximal Covering Problem with Some Negative Weights

This article presents the maximal covering problem on a network when some of the weights can be negative. Integer programming formulations are proposed and tested with ILOG CPLEX. Heuristic algorithms, an ascent algorithm, and simulated annealing are proposed and tested. The simulated annealing approach provides the best results for a data set comprising 40 problems.     

Human occupation and geomorphological evolution of the Thessaloniki Plain (Greece) since mid Holocene

The plain of Thessaloniki is an important area from a historical standpoint. Numerous reigns and empires have occupied the area, leaving behind numerous archaeological remains. The literature and historical evidences show that the city of Pella was located near the sea and its harbor was the starting point of various conquests of famous kings such as Philip the 2nd and Alexander the Great. At present, the ancient capital is located 28 km inland the large fertile plain of Thessaloniki.     

The Expected Maximum Distance Objective in Facility Location

Abstract In this paper we introduce a new objective function for the minimax location problem. Every demand point generates demand for service with a given probability (during a given period of time) and the objective is to minimize the expected maximum distance. The planar problem is proven to be convex and thus standard solution techniques such as using the Solver in Excel can be applied for its solution. Properties for the problem on the network are proven and an efficient algorithm proposed for its solution.     

Warfare in Prehistoric and Early Historic Eastern North America

Recent criticisms of the use of historically and ethnographically recorded conflicts as models for warfare in prehistoric times force archaeologists to reexamine assumptions about the frequency, severity, and effects of intergroup fighting. In eastern North America, skeletons of victims and palisaded settlements—the only information consistently available on intergroup hostilities—indicate that the prevalence of conflicts varied greatly over time and space. Occasionally the attacks, typically ambushes of small numbers of people, cumulatively resulted in numerous casualties.Variation in palisade strength is consistent with the organizational structure and warrior mobilization potential of late prehistoric societies in different parts of the Eastern Woodlands.