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141.
There is increasing concern about environmental impacts of acidic drainage from acid sulphate soils on Holocene estuarine flood plains. Acidity derives from oxidation of iron pyrite in the sediments. Natural factors determine concentrations and distributions of pyrite accumulations, but human activities have reduced pyrite accumulation in the Pearl River Delta with land use practices increasing terrestrial sediment discharge. Large freshwater discharges and management techniques have enabled sustainable use of these soils. High concentrations of pyrite occur in many estuarine flood plains of Australia because of relatively greater marine inputs. Drainage of these soils enhances pyrite oxidation and estuarine acidification, which is associated with fish-kills. For sustainable development, the problems of acid sulphate soil drainage must be recognised and overcome.  相似文献   
142.
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   
143.
Book reviews     
MIDDLE EAST AND FAR EAST, Allan S. Walker, M.D., Ch.M., F.R.A.C.P. Published by the Australian War Memorial, Canberra. Obtainable at all booksellers, price 35/‐.

UNESCO, HUMANISM AND EDUCATION IN EAST AND WEST — Published in 1953 by the United Nations. 224 pages.

THE ALTERNATIVE (a dynamic approach to our relations with Asia). By John Burton, B.A., B.Ec., Ph.D., Sydney. Morgans Publications, 1954. PP. 116.

TING HSIEN — A North China Rural Community: By Sidney D. Gamble (Institute of Pacific Relations, New York, 1954). U.S. $6.50.

ZWISCHEN BEFREIUNG UND FREIHEIT. DER SONDERFALL OSTERREICH, by Karl Gruber. Verlag Ullstein. Wien, 1953.

AMERICAN ECONOMIC POLICY TOWARDS THE PHILIPPINES: By Shirley Jenkins — With an introduction by Claude A. Buss. Published under the auspices of the American Institute of Pacific Relations by Stanford University Press, California, 1954. P. 181.

THE ORIGINS OF PRUSSIA: By F. L. Carsten—Clarendon Press. Oxford, 1954. 309 pp., 1 map. (55/6 sterling).  相似文献   

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Traditional notions that family life among slaves during the pre-plantation period in the non-Hispanic Caribbean was necessarily unstable are fading in light of new research. Although marriage among this segment of the population in Caguas, Cayey, San Germán, and Yauco--rural parishes in Puerto Rico--involved only a fraction of the overall number of marriages in these communities, the marriage of slaves was much more frequent than previously assumed. Family life among the eighteenth-century Puerto Rican slave population appears to have been quite stable, as shown by the reconstruction of birth intervals for both married and unmarried mothers. Married and unmarried mothers exhibited similar reproductive behavior. These results strongly suggest that a majority of the unmarried slave mothers lived in unions that were not institutionally recognized, but that were nevertheless stable, as indicated by the high percentage of their children born at intervals comparable to those of married mothers. If unmarried mothers were living in stable consensual unions, then our understanding of these slave family units during the colonial period must be reassessed not only for Puerto Rico but possibly for the rest of the Caribbean and Latin America.  相似文献   
147.
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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We develop a new conceptual approach to locating inspection stations for hazardous vehicles, prevention, and compare it to the previous, punitive, philosophy of the flow-capturing location model. We implement this preventive protection philosophy with a new mixed integer program that maximizes hazard avoidance by locating a number of inspection stations to detect and remove hazardous vehicles as early in their trips as possible. We test the model's performance and analyze the spatial characteristics of solutions simulating several potential applications. Our computations demonstrate that a relaxed integer-linear program is overly demanding computationally and that a simple greedy heuristic lacks robustness. We suggest further approaches to developing more powerful and efficient solution methods.  相似文献   
150.
Non-destructive X-ray fluorescence analyses induced by white synchrotron radiation (SYXRF) have been performed on a page of the Gutenberg Bible and 21 other different single leaves printed in the years 1470 to 1500. Absolute elemental areal densities for the papers and the inks are reported. The known high Cu and Pb content in Gutenberg's ink is confirmed. The elemental compositions of the other inks, if measurable by XRF at all, are in general very low, governed only by a few additional elements and found to be not distinctive for a known printer. This will render an identification of the printer or printing offices by ink composition analysis in the period after 1470 difficult.  相似文献   
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