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The influence of altered fire regimes on the denudation of a catchment is determined from alluvial deposits of the last 10,000 yrs and by monitoring runoff and erosion before and after a wildfire. An increase in fire frequency beginning at 3,000–4,000 yrs BP, as a result of intensified Aboriginal burning, did not change the mechanisms or rates of denudation nor did it cause widespread alluviation as suggested by others. The results of monitoring show that before and after mild fires there is insufficient runoff on most slopes to entrain sediment. Only after intense fires are runoff and erodibility increased enough to significantly accelerate erosion. Conditions are then identified which are most likely to lead to accelerated erosion from altered fire regimes in other catchments.  相似文献   

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This article synthesizes recent advances in the study of astronomy and worldview in architectural and urban planning in Mesoamerica. Throughout most of this cultural area, the practice of orienting civic and ceremonial buildings followed similar principles, although regional and time-dependent variations are present. Analysis of alignment data has revealed the existence of distinct and widespread orientation groups; most refer to sunrises and sunsets on particular dates, although two groups can be related to lunar and Venus extremes. Astronomically relevant directions frequently dominate considerable parts of urban layouts. The orientation and the location of important buildings often were conditioned by astronomical criteria and beliefs about specific landscape features; particularly notable are structures that were aligned to prominent mountaintops on the local horizon. Based on a variety of contextual data, I interpret the uses and significance of orientations in terms of agricultural concerns, cosmological concepts, and political ideology. I outline the evolution of orientation practices, drawing attention to pan-Mesoamerican trends, regional patterns, and diffusion processes.  相似文献   

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弘扬历史研究中的民族精神和时代精神   总被引:1,自引:0,他引:1  
当今世界各国之间的竞争主要表现为综合国力之争,文化在综合国力竞争中的地位和作用越来越突出,文化的力量深深熔铸在民族的生命力、创造力和凝聚力之中。民族精神是文化的重要组成部分,作为民族文化优良传统的历史积淀,民族精神具有超强的社会整合功能。历史发展和历史研究中体现出的民族精神和时代精神,对于提高文化实力和综合国力有着重要作用。  相似文献   

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龙感湖、太白湖是经济发达的长江中下游地区重要的浅水湖泊。本研究首先利用历史学的方法复原了黄梅、广济(武穴)和宿松三县1391-2006年的人口时间序列,这是首次将中国历史人口序列的重建深入到县一级。以此为基础,重建了1391-2006年龙感湖-太白湖流域的历史人口序列。在复原方法上,重点吸收了何炳棣等学者关于史载人口数...  相似文献   

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Drawing on experiences from a project conducted in the ‘Drentsche Aa’ area in the Netherlands, this article discusses the concept of the ‘rural atelier’ as a form of problem-based learning. The rural atelier principle was used originally in rural development planning and described as such by Foorthuis (2005) and Elerie and koopman (2008). Here, we discuss it in the context of landscape education. Experiences from a case study project are presented.  相似文献   

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This study uses GIS techniques to examine the spatial distribution of stream power along major streamlines in the Lane Cove catchment in northern Sydney, Australia. Channel gradient estimates derived from a 5 m resolution digital elevation model (DEM) are combined with streamflow data to estimate stream power along river courses. Stream power and its constituent components are then related to a detailed field‐based assessment of sediment storage along the trunk stream and primary tributaries. At the catchment scale, sediment storage per unit length decreases as channel gradient and gross stream power increase. However, local controls such as variability in valley width and occurrence of confluence zones exert a greater influence upon sediment storage, disrupting systematic catchment‐wide relationships. The total volume of storage along each streamline has a strong linear relationship to the area of the subcatchment, but the distribution of sediment along streamlines varies between subcatchments. The GIS framework employed in this project allows generation of continuous, empirical data, thereby providing catchment‐specific predictive capacity that can accompany theoretical approaches to stream power modelling.  相似文献   

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The aim of this article is to examine conceptually and empirically how innovative firms combine knowledge (1) provided by different sources, (2) accessed at different spatial scales and (3) acquired through different channels. We add to the conceptual debate by contrasting and synthesising the perspectives offered on these issues by four key concepts, namely the local buzz and global pipelines argument, the knowledge-base approach, the notions of Science–Technology–Innovation and Doing–Using–Interacting modes of innovation as well as the regional innovation systems concept. The empirical part of the article contains an analysis of knowledge-sourcing activities employed by 181 firms belonging to the Austrian automotive supplier industry. Our findings reveal that it is, indeed, combinations of knowledge sourced from different partners located at different spatial scales and acquired through different channels that are relevant. However, it is particular combinations that dominate while others are negligible. Austrian automotive supplier firms combine knowledge provided by customers with knowledge inputs from a variety of other sources. Most of the combinations involve the European or global levels combined with the regional and/or national level. Finally, firms combine spillovers with a variety of other channels to acquire innovation-relevant knowledge.  相似文献   

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Scales of regional income disparities in the USA, 1955 2003   总被引:3,自引:0,他引:3  
This article examines multiple dimensions of regional per capitaincome disparities in the USA between 1955 and 2003 with a particularfocus on scalar effects. It combines various exploratory analyticaltools of spatial disparities, including inequality indices,mobility indices, kernel density estimation, spatial autocorrelationstatistics and scale variances, to analyse regional averageper capita income distributions at multiple spatial scales,ranging from counties to multi-state regions. The analysis revealspreviously unrecognised systematic patterns of cross-scalardynamics, whereby spatial income disparities are increasinglymore pronounced at smaller scales in the last few decades.  相似文献   

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The lack of interest in history in ancient India has often been noted and contrasted with the situation in China and the West. Notwithstanding the vast body of Indian literature in other fields, there is a remarkable dearth of historical writing in the period before the Muslim conquest and an associated indifference to historiography. Various explanations have been offered for this curious phenomenon, some of which appeal to the supposed currency of certain Indian philosophical theories. This essay critically examines such "philosophical explanations."
I argue that it is not true that there was no history in ancient India, and it is not surprising that there was no developed historiography or scientific history. It is both true and surprising that there was no real importance attached to history in ancient India. An adequate philosophical exxplanation for this historica phenomenon, however, is not to be found in appeals to the influence of indigenous metaphysical theories about time and the self. A much more plausible philosophical explanation appeals instead to certain features of classical Indian epistemology.  相似文献   

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In 1842, the Parisian editor Louis-Antoine Pagnerre published the Dictionnaire politique. This large volume was the manifesto of the French Republicans in opposition to the conservative governments of King Louis-Philippe under the July Monarchy. One of the most original aspects of the Dictionnaire resides in the attempt to link the doctrine of republicanism to political economy. It is the purpose of this paper to analyse the republican political economy presented in Pagnerre's dictionary. First, we detail the historical context in which it appeared, stressing on Pagnerre's biography and on the composition of the group of young republicans who wrote the main economic entries of the book. Second, we focus on the economic ideas about the political regulation of industrial phenomena and the solutions these Republicans imagined to solve the social question. Third, we conclude by attempting to summarize the main characteristics of this republican political economy and to appreciate its originality.  相似文献   

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