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The active layer is the zone above permafrost that experiences seasonal freeze and thaw. Active‐layer thickness varies annually in response to air and surface temperature, and generally decreases poleward. Substantially less is known about thaw variability across small lateral distances in response to topography, parent material, vegetation, and subsurface hydrology. A graduated steel rod was used to measure the 1998 end‐of‐season thaw depth across several transects. A balanced hierarchical sampling design was used to estimate the contribution to total variance in active‐layer depth at separating distances of 1, 3, 9, 27, and 100 meters. A second sampling scheme was used to examine variation at shorter distances of 0.3 and 0.1 meter. This seven‐stage sample design was applied to two sites in the Arctic Foothills physiographic province, and four sites on the Arctic Coastal Plain province in northern Alaska. The spatial variability for each site was determined using ANOVA and variogram methods to compare intersite and inter‐province variation. Spatial variation in thaw depth was different in the Foothills and Coastal Plain sites. A greater percentage of the total variance occurs at short lag distances (0–3 meters) at the Foothills sites, presumably reflecting the influence of frost boils and tussock vegetation on ground heat flow. In contrast, thaw variation at the Coastal Plain sites occurs at distances exceeding 10 meters, and is attributed to the influence of well‐developed networks of ice‐wedge polygons and the presence of drained thaw‐lake basins. This information was used to determine an ongoing sampling scheme for each site and to assess the suitability of each method of analysis.  相似文献   
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A theoretical policy model is presented that combines regional dynamic CGE modeling and optimal control to explore the role of local government taxation and expenditure in enhancing regional growth. It contributes to the regional CGE literature by explicitly solving for an optimal policy and augments earlier regional optimal control models by adding endogenous optimization of producer and consumer agents in response to endogenously determined prices. Results of three policy regimes are analyzed in terms of gains in the objective function, impacts on income inequality, and sensitivity to model parameterization.  相似文献   
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This paper examines participation and representation in ATSIC elections over the 10 year period since 1990. It attempts to identify patterns of participation and representation that seem to be emerging and what these might suggest about ATSIC's operation. By examining numbers of nominees compared to positions available, the paper suggests that ATSIC elected office has been fairly keenly and consistently sought and competed for by Indigenous people, though there may have been some slight initial reticence in the 1990 elections. By examining voter numbers and voter turnout, the paper suggests that voter participation nation-wide rose slightly from 1990 to 1996 and then largely stabilised in 1999. It also suggests that there have been significant variations from this national pattern at State and Territory levels and it explores some reasons for this. The paper also examines voter numbers and voter turnout at the ATSIC regional level since 1993 and finds that there has been much higher voter turnout in the sparsely settled regions of northern Australia and much lower voter turnout in the southern and urban areas. This is explained in terms of ATSIC program and expenditure priorities and in terms of polling place access. The final two sections of the paper examine the representation of women and Torres Strait Islanders among ATSIC elected representatives. Both are seen as significant issues which should be of some ongoing concern within ATSIC, alongside the issue of the southern/northern difference in voter participation.  相似文献   
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In this paper I explore some of the textual possibilities of post‐colonial geography. Using the conceptual tool of place as a palimpsest, I trace some geographies of memory across selected colonial and post‐colonial texts. By focusing on the relationship between representations of ‘sunny Perth’ and ‘Nyungah Perth’, I tease out some of the more general theoretical issues which pertain to a politics of place and space within this (post)colonial Australian context. The nexus of memory, place and cultural identity is central to my analysis. I give particular attention to the ways in which cultural memories are inscribed in some very specific and very ordinary places, and how these places become site‐markers of the remembering process and of identity itself.  相似文献   
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Single and Multiscale Models of Process Spatial Heterogeneity   总被引:3,自引:0,他引:3       下载免费PDF全文
Recent work in local spatial modeling has affirmed and broadened interest in multivariate local spatial analysis. Two broad approaches have emerged: Geographically Weighted Regression (GWR) which follows a frequentist perspective and Bayesian Spatially Varying Coefficients models. Although several comparisons between the two approaches exist, recent developments, particularly in GWR, mean that these are incomplete and missing some important axes of comparison. Consequently, there is a need for a more thorough comparison of the two families of local estimators, including recent developments in multiscale variants and their relative performance under controlled conditions. We find that while both types of local models generally perform similarly on a series of criteria, some interesting and important differences exist.  相似文献   
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