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Laguna Guatavita, a crater‐like lake located in central Colombia, was used by pre‐Columbian Muisca people for a variety of socio‐religious ceremonies, many of which involved casting offerings into the lake. Of these, the installation of a new ‘king’ became the basis of the El Dorado myth that was carried back to Europe by 16th century conquistadores. In the present study, beads collected from Laguna Guatavita during a late 19th/early 20th century attempt to recover valuables from the lake bed, have been subjected to geochemical analysis. Results establish that these artefacts have been fabricated from Class Ib amber. Class Ib ambers have not previously been reported in either the geological or archaeological records of Central or South America, and their existence in this context implies that the Muisca people had access to a unique local or regional source of amber, knowledge of which has subsequently been lost.  相似文献   

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As part of an ongoing project at the World Heritage Site of Bukhara, we investigated the glue used in the construction of the Khoja Zaynuddin mosque. Analysis by a range of techniques confirmed that it consisted of a collagen‐based glue. However, the glue contained many non‐protein constituents. The presence of lipid material suggests that the glue was produced by a relatively unsophisticated process. More surprisingly, various marker compounds of urine were found. Study of the viscosity of a mixture of a modern collagen‐based glue and urea showed that the presence of urea at a concentration typical of human urine reduced the viscosity of the glue, thus improving its spreading characteristics and enabling its use at a lower temperature. Whilst the advantages of adding urea to glue were known to craftsmen in Europe and America in the 19th century, it would appear that the builders of Bukhara were aware of the technique, using less pure components, at a significantly earlier date.  相似文献   

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ABSTRACT This paper uses a logit model of consumer choice to examine how changes in the spatial behavior of rural consumers will affect the commercial base of smaller urban places. Various socio-economic changes in a region can be expected to cause a number of behavioral changes, including changes in where people work and shop. The analysis presented in the paper emphasizes the importance of location to the commercial prospects of small trade centers as consumers become more spatially mobile and engage in more multipurpose shopping. Places that are centrally located have the best prospects for ensuring that functions are either maintained or suffer the least decline as a result of competition from higher-order centers. Remoter locations will be adversely affected by these competitive pressures.  相似文献   

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This paper examines the net fiscal benefits of various federal grants and taxes paid to finance them. Net, effective tax rates are calculated for all county areas in the U.S. for seven measured grant programs, and the distributions of such tax rates are examined in conjunction with the median family incomes of the county areas. Inferences about the progressivity (or regressivity) of the grant programs are made, as well as inferences about the horizontal equity of the grant programs through the use of a new class of index numbers. It was found that more progressive grant formulas, which provide greater rates of subsidy to areas with lower median family incomes, also tend to be less horizontally equitable.  相似文献   

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ABSTRACT. Total cleared area in a von Thünen land-use model drives an atmosphere externality which depresses agricultural productivity uniformly throughout the region. Exogenous events that encourage clearance and use of a larger cultivated area (output price or population increase) exacerbate the externality. Imposition of a simple, corrective tax on land rents does not reverse these patterns but does mitigate the increase in the externality and leaves cultivators with higher incomes than they would obtain without the tax. We examine an optimal tax on land rents, designed to maximize the social value of land rents in the region, and an output tax.  相似文献   

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ABSTRACT We study how the city system is affected by the possibility for the members of the same cultural diaspora to interact across different cities. In so doing, we propose a simple two‐city model with two mobile cultural groups. A localized externality fosters the productivity of individuals when groups interact in a city. At the same time, such interaction dilutes cultural identities and reduces the consumption of culture‐specific goods and services. We show that the two groups segregate in different cities when diaspora members find it hard to communicate at distance whereas they integrate in multicultural cities when communication is easy. The model generates situations in which segregation is an equilibrium but is Pareto dominated by integration.  相似文献   

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Summary. This paper aims to provide a framework of literary evidence as a basis for study of the relations between the Roman Empire and Scandinavia from an archaeological point of view. It covers the period from Augustus to the end of the fourth century.  相似文献   

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ABSTRACT Trade, foreign direct investment, and inter‐regional R&D spillovers facilitate competition, the spread of knowledge, and the adoption of more advanced technologies, which in turn hastens total factor productivity (TFP) growth. The spread of these efficiency gains from internationalization requires a sufficient local knowledge to enable them to be adapted to the domestic productive environment. Thus, higher local knowledge and internationalization will lead to TFP growth, and the greater the complementarity between variables the higher the TFP growth. We test the complementarity hypothesis using Spanish regional data over the period 1980–1995 in which both regional local knowledge and internationalization experienced a notable increase.  相似文献   

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张浩哲  杨庆媛 《人文地理》2021,36(3):108-116
依据人口统计数据与NPP-VIIR夜间灯光影像识别出2013-2017年中国收缩城市,运用超效率SBM模型测算收缩城市土地利用效率,并构建Tobit模型分析其影响因素.结果发现:①2013-2017年,收缩城市土地利用效率均值降低了1.44%,且各年份均低于增长城市与全部城市.实现土地有效利用的收缩城市占比较小,大多数...  相似文献   

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