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David I. Stern 《政策研究杂志》2007,35(2):291-322
Prior to Mexico's entry to the North American Free Trade Agreement (NAFTA), predictions of the consequent impact on the environment in that country ranged from the dire to very optimistic. This article investigates NAFTA's outcomes in terms of energy use and the emission of atmospheric pollutants. Specifically, has entry into NAFTA led to a convergence or divergence in indicators of emissions, environmental efficiency, and emissions‐specific technology in Mexico, the United States, and Canada? A battery of tests is applied to these indicators for energy use and carbon, sulfur, and NOx emissions in the three countries. The results show that the extreme predictions of the outcomes of NAFTA have not materialized. Rather, trends that were already present before the introduction of NAFTA continue and, in some cases, improve post‐NAFTA, but not yet in a dramatic way. There is strong evidence of convergence across the three countries toward a lower intensity of energy use and emissions per unit of GDP. Although intensity is rising initially for some variables in Mexico, it eventually begins to fall post‐NAFTA. Per capita emissions of sulfur and NOx also show convergence, but this is not the case for energy and carbon, and the latter variables also drift moderately upwards. The state of technology in energy efficiency and sulfur abatement is improving in all countries, although there is little, if any, sign of convergence and NAFTA has no effect on the rate of technology diffusion. However, total energy use and carbon emissions increase both pre‐ and post‐NAFTA and total NOx emissions increase in Mexico. Only total sulfur emissions are stable and falling in all three NAFTA partners. 相似文献
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Community‐based efforts to address environmental problems occupy an increasingly large space on the environmental policy landscape. Advocates argue that local environmental institutions (LEIs) can deliver both procedural and environmental quality benefits. Yet, despite over a decade of expansive support, the performance of LEIs remains largely unknown, particularly with regard to environmental outcomes. In this article, we consider new environmental outcome data we compiled from local efforts to implement the Massachusetts Wetlands Protection Act. We find that stronger forms of LEIs generate both quantitatively and qualitatively better environmental outcomes, which suggests that LEIs may live up to their advocates’ expectations. 相似文献
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David Rhode Zhang Haiying David B. Madsen Gao Xing P. Jeffrey Brantingham Ma Haizhou John W. Olsen 《Journal of archaeological science》2007
Transitions from terminal Pleistocene Upper Paleolithic foraging to Holocene Neolithic farming and pastoralist economic orientations in the northern Tibetan Plateau are examined from the perspective of Epipaleolithic sites located near Qinghai Lake, Qinghai Province, western China. Jiangxigou 2 is an artifact-rich, multicomponent midden site with the main period of occupation dating ca. 9000–5000 cal yr BP, containing abundant flaked stone artifacts including a substantial proportion of microlithic tools, abundant faunal remains including gazelle, deer, and sheep, and a small number of ceramics, including the oldest known on the Tibetan Plateau. Heimahe 3, on the other hand, is a brief hunter's camp dating ca. 8450 cal yr BP, with evident affinities to late Upper Paleolithic camps in the same region that date several thousand years older. The two distinctively different sites are probably nodes within a single Epipaleolithic foraging system that developed on the margins of the high Tibetan Plateau during the early Holocene, and that served as a basis for colonization of the high-altitude Plateau at that time. Jiangxigou 2 appears to be connected to early Neolithic agricultural settlements along the upper Yellow River (Huang He) drainage during the middle Holocene, and may provide insights into forager–agriculturalist interactions that lead to the development of pastoralist systems in the region. 相似文献
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Ya-Qin Hu Zhong-Li Zhang Subir Bera David K. Ferguson Cheng-Sen Li Wen-Bin Shao Yu-Fei Wang 《Journal of archaeological science》2007
The provenance of more than 2200-year-old terracotta warriors and horses in the Qin Shihuang Mausoleum is still a mystery, even though some researchers have inferred that the terracotta figures were produced near the mausoleum. The sporomorphs (pollen and spores) extracted from terracotta fragments of a warrior and a horse and compared with those obtained from soil samples from the Qin Dynasty layer in Pit No. 2 of the Qin Shihuang Mausoleum indicate that the pollen spectrum from the terracotta horse is different from that of the warrior, but similar to the local soil samples. Herbaceous pollen was dominant in the warrior sample, while arboreal pollen predominates in the horse and soil samples. Palynological evidence suggests that the terracotta horses were produced at a locality near the mausoleum, while the warrior came from a site which was further afield. 相似文献
147.
During recent reinvestigations in the Great Cave of Niah in Borneo, the ‘Hell Trench’ sedimentary sequence seen by earlier excavators was re-exposed. Early excavations here yielded the earliest anatomically-modern human remains in island Southeast Asia. Calibrated radiocarbon dates, pollen, algal microfossils, palynofacies, granulometry and geochemistry of the ‘Hell Trench’ sequence provide information about environmental and vegetational changes, elements of geomorphic history and information about human activity. The ‘Hell’ sediments were laid down episodically in an ephemeral stream or pool. The pollen suggests cyclically changing vegetation with forest habitats alternating with more open environments; indicating that phases with both temperatures and precipitation reduced compared with the present. These events can be correlated with global climate change sequences to produce a provisional dating framework. During some forest phases, high counts of Justicia, a plant which today colonises recently burnt forest areas, point to fire in the landscape. This may be evidence for biomass burning by humans, presumably to maintain forest-edge habitats. There is evidence from palynofacies for fire on the cave floor in the ‘Hell’ area. Since the area sampled is beyond the limit of plant growth, this is evidence for human activity. The first such evidence is during an episode with significant grassland indicators, suggesting that people may have reached the site during a climatic phase characterised by relatively open habitats ∼50 ka. Thereafter, people were able to maintain a relatively consistent presence at Niah. The human use of the ‘Hell’ area seems to have intensified through time, probably because changes in the local hydrological regime made the area dryer and more suitable for human use. 相似文献
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David A. Higgins 《International Journal of Nautical Archaeology》1995,24(1):47-52
This paper outlines the value of pipes to Post-Medieval archaeologists and discusses the potential contribution of underwater groups. It seeks to encourage closer collaboration between underwater archaeologists and finds specialists by suggesting some priorities for future research and by drawing attention to the key publications and organizations concerned with the study of pipes 相似文献