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101.
Acid sulphate soils form when iron pyrite oxidises to sulphuric acid on atmospheric exposure, lowering soil pH below 4. In the Richmond River estuary, northern New South Wales, flood mitigation, drainage works and floodplain excavations have augmented acid sulphate soil formation by increasing pyrite availability for oxidation. These engineering works have facilitated the transport of acidified water and have impeded recovery from tributary acidification. The increased frequency and duration of acidification are associated with elevated concentrations of inorganic monomeric aluminium and dissolved iron, and major iron hydroxide precipitation, with deleterious effects on exposed aquatic biota and habitat. Fish kills and an outbreak of epizootic ulcerative syndrome (EUS) have been recorded from acidified sites in the estuary.  相似文献   
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Reviews     
“JINNAH: CREATOR OF PAKISTAN.” by Hector Bolitho. John Murray. London, 7954. Pp. x and 244, illus.

“WANTED: AN ASIAN POLICY,” by Edwin O. Reisehauer. New York: Knopf, 7955. Pp. 256.  相似文献   

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The Early Historic Period in the Mun Valley occupies a critical three centuries, from A.D. 500 to A.D. 800, a period often known as that of Zhenla, a name derived from early Chinese accounts. This article first describes early findings of fieldwork designed to illuminate the prehistory of the upper Mun Valley, a period which covers approximately two millennia, with initial settlement now dated between 1500 and 1000 B.C. It then considers the nature of the transition to the complex polities of Zhenla. This involves a combination of archaeological and documentary evidence. Sources for the latter are rare for the Mun Valley, but by broadening the area considered, it is possible to integrate archaeological and historical sources in order to portray the intensifying social changes which characterize the Early Historic Period. It is suggested that most of the Mun Valley was occupied by Khmer speakers during the Iron Age, people responsible for the transition to increasingly centralized polities of the Early Historic Period. In the upper reaches of the Mun catchment, and in the Chi Valley to the north, the late prehistoric inhabitants spoke Mon. They had close affinities with the Dvaravati polities of Central Thailand. If confirmed, this hypothesis would indicate a series of local trends towards increasing social complexity which we can recognize in the early epigraphic record.  相似文献   
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Scholarship concerning the lives of enslaved African Americans in southern New England has shifted rapidly from outdated models of acculturation to conflict-driven models of domination and resistance. With the assumption of conflict as the outcome of all power relations, both economic production and historical contextuality have been overlooked, with slavery systems in New England simply equated with other regions of the Atlantic world, rather than compared and contrasted. This essay reconsiders contests over power in seventeenth- and eighteenth-century New England. Drawing on the work of Greene (1966), Piersen (1988), and others, I argue that the system of slavery in the region may represent an anomalous case in terms of the means of control or the means of resistance. By examining demographic patterns, economic production, and agricultural landscapes in Rhode Island's East Bay, I argue that there may be more to be learned from William D. Piersen's (1988, p. 143) concept of resistant accommodation as a middle ground between the two extremes of the theoretical spectrum. The essay concludes with suggestions for further research on the archaeology of African-American lives in the region.  相似文献   
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The state school curriculum, and geography in particular, played a role in encouraging emigration to the colonies, if not in actually educating for emigration. Emigration was an implicit and explicit topic in school geography, and was increasingly endorsed after the 1885 Revised Instructions to inspectors of schools which explicitly sought the promotion of emigration to young people as an “honourable enterprise”. Early-twentieth century school geography texts were part of the broader imperial discourse which valorized the settler Dominions over the tropical colonies and portrayed them as the good citizen's choice for emigration. The 1922 Empire Settlement Act represented the British government's most direct intervention in supporting out-migration from Britain, but texts at this time were generally less jingoistic than some of their forerunners, in keeping with the changed attitudes in post-World War I Britain.  相似文献   
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