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31.
32.
A palaeoecological approach was undertaken to investigate the last 400 years of change in vegetation, fire, nutrient mobility, lake productivity and erosion associated with Aboriginal and European land-use practices in a forested environment in eastern Victoria. Melaleuca ericifolia scrub, although present prior to European settlement, has expanded around Lake Curlip in the last 200 years, primarily due to the action of fire on a forest already weakened by drought. A fern understorey has declined in extent and a more open aspect has developed in the forest. Fire has been a major component of vegetation dynamics in the historical period. Erosion rates were comparatively low and associated with fire during prehistoric times, but after European settlement its increase is more closely related to land clearance and flooding than fire. The response of vegetation to both anthropogenic and natural influences changed during the historical period. Although fire is an integral part of vegetation change, it is not an over-riding effect at Lake Curlip. Drain construction in the swamp has reduced the impact that any accumulation of pasture improvement chemicals may have had on eutrophication of the lake. 相似文献
33.
ABSTRACT. The dynamic relationship between sectoral value added and regional economic growth is analyzed using a stochastic intersectoral model estimated by ordinary least squares and linear systems techniques. A state-space portion of the model identifies the time element of sedoral value added. Dynamic multipliers, tracing the temporal path of regional growth, are calculated for the state of Georgia over the period 1963–1986. This application shows that the impacts of sectoral shocks can follow cyclical as well as monotonic patterns and that the direction and magnitude of the impact may change over time. 相似文献
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Charcot-Marie-Tooth disease is a hereditary motor and sensory neuropathy first described in 1886. Our increasing knowledge of this disease correlates well with the development of methods used in neurology over the past 100 years. Although its physiopathology and treatment is still not fully understood, current developments in techniques are opening the way to future discoveries. We have divided its history into three theoretical periods: the first from 1886 to 1956, which was devoted to clinical and pathological study of the disease; the second from 1956 to 1982, which saw the development of electromyography in the investigation of neuromuscular diseases; and the last and current period based upon genetic research, using the methods of molecular biology. 相似文献
36.
Spatial compactness has been proposed as a suitable criterion for assessing whether electoral boundaries reflect partisan interests. Although several different measures of spatial compactness have been developed, only limited efforts have been made to compare and evaluate them in the context of electoral redistricting. This paper assesses alternative spatial compactness measures and applies conceptually appealing measures to the provincial ridings proposed by British Columbia's Royal Commission on Electoral Boundaries (1988). 相似文献
37.
James G. Strathman 《Journal of regional science》1992,32(4):501-509
ABSTRACT. This paper examines the impacts of JRS articles in the areas of theory, methods and empirical analysis, as represented by subsequent citations reported in the Social Sciences Citation Index. A model relating the mix of theoretical, methodological and empirical research published in the JRS to subsequent citations is estimated. The time distribution of theoretical and empirical citations also indicates that the knowledge diffusion process in these two areas may be segmented. 相似文献
38.
Three rare Himyaritic coins found in the territory of the ancient Hadramawt kingdom are published for the first time. Two of the coins bear the name of the king,'Amdan Bayyin, while the third has the name of Tha'ran Ya'ub. 相似文献
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Günter Grönbold 《Indo-Iranian Journal》1992,35(4):273-297
Summary At the end of the second chapter of the Buddhist Klacakra-Tantra (dated c. 10th century) we find a group of verses in which several doctrines are characterized and criticized: Brahmanism, Vaisnavism, aivism, materialism, Islam and Jainism. Moreover the text refers to Buddhism itself as well as the so-called heterodox Buddhist schools. It is the only old Sanskrit text known until now in which the Islam is mentioned and recognized as a doctrine. 相似文献