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81.
Using the properties of the Gini coefficient, a structural model is developed to assess the impact of uniform changes in environmental compliance costs on the distribution of per capita emissions across U.S. counties and states, a distribution that places a larger burden on minorities. Using data from the U.S. EPA's Toxic Release Inventory and three state-specific measures of environmental compliance costs, we find that uniform increases in federal environmental standards have little impact on the distribution of environmental hazards, and may actually exacerbate spatial inequality. As a result, Federal standards that target specific high pollution locations are necessary to redress current inequities. 相似文献
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This paper presents a methodological tool of statistical correction to assess the capacities of different Roman amphorae, whereby ceramic values are transformed into amounts of transported product. Based on scaled drawings of 1281 Roman amphorae, individual vessels’ capacities have been calculated by applying a CAD software to the inner profiles. Each vessel has been classified according to amphora types and the mean for each type has been calculated to produce a coefficient called Average Capacity (AC). The estimated capacities are highly reliable and show narrow confidence intervals. Therefore, they can be applied immediately as a correction factor in studies of quantification of amphorae aimed at characterizing trading dynamics. As such, we expect that future statistical studies of amphorae will include this statistical coefficient to produce more precise and reliable analysis of assemblages and, consequently, more accurate research on the Roman economy. 相似文献
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The marsh deer (Blastocerus dichotomus, Illiger, 1815) is the largest contemporary South American deer, and its habitat includes the floodplains and wetlands of eastern South America. Throughout the Holocene these deer were widely used by indigenous societies, from the southern banks of the Amazon River to the Río de la Plata River, and from the Andean foothills to the Atlantic Ocean. However, despite the enormous ecological and archaeological importance of this ungulate in the region, our knowledge of the isotopic values of their diet is almost nonexistent. This paper is the first systematic approach to the study of the isotopic values of this mammal's diet, using archaeological and present-day samples from interconnected watersheds of the Paraná and Uruguay rivers in east-central Argentina. The results obtained from 24 measurements indicate an average value of ?21.09 ± 1.46‰ in δ13C collagen, with a low coefficient of variation (6.92%). The data indicate a marked preference for consumption of plants with a C3 photosynthetic pathway. Most of the observed variability in the isotopic values corresponds to the period 900–1430 14C years BP, a time range during which the values show higher consumption of C4 plants. This it could be related with a period where temperature and associated humidity increased, synchronous in the area with the Medieval Climate Anomaly. 相似文献