排序方式: 共有145条查询结果,搜索用时 250 毫秒
41.
María Barajas Pedro Bosch Claudia Malvaéz Cristina Barragán Enrique Lima 《Journal of archaeological science》2010
A painted monolith, as important as the Aztec Calendar or the Coyolxauhqui, has been discovered in the ritual Aztec center of Mexico City. It represents Tlaltecuhtli, the bisexual manifestation of the Earth from whom all life comes. Still, pigments, which have lost their conglomerating resins, have to be retained. In this study, the consolidation of ochre pigment on original fragments from the Aztec sculpture is presented. Several compounds were tested as consolidants, on the one hand natural polysaccharides, Funori and Slobber of Nopal exudate, on the other derivatives of cellulose, Methocel® and Klucel®, and also commercial consolidants as KSE 300® and Paraloid B72®. To simulate the ageing of consolidated samples, they were treated in an Accelerated Weathering Tester. Then, both sets of samples, fresh and aged, were characterized structural, morphological and texturally by using X-ray diffraction, electronic microscopy and nitrogen adsorption, respectively. A leaching test was performed on consolidated samples to evaluate the consolidant efficiency. 相似文献
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Enrique Cerrillo-Cuenca Pedro Ortiz-Coder José-Ángel Martínez-del-Pozo 《Archaeological and Anthropological Sciences》2014,6(3):227-239
A non-invasive procedure for assessing and interpreting the pigments of rock art paintings through computer vision and photogrammetric techniques is presented. The method is designed to document and interpret poorly preserved pigments by making use of advanced techniques of photogrammetry and computational imaging. Two different software solutions that were developed by the authors have been used for this purpose. Finally, two case studies of rock art paintings from Spain have been analysed, which show the reliability of the method. 相似文献
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Nuno Mendes Alexandre A. Costa Paulo B. Lourenço Rita Bento Katrin Beyer Gianmarco de Felice 《International Journal of Architectural Heritage》2017,11(1):59-71
ABSTRACTEarthquakes cause severe damage to masonry structures due to inertial forces acting in the normal direction to the plane of the walls. The out-of-plane behavior of masonry walls is complex and depends on several parameters, such as material and geometric properties of walls, connections between structural elements, the characteristics of the input motions, among others. Different analytical methods and advanced numerical modeling are usually used for evaluating the out-of-plane behavior of masonry structures. Furthermore, different types of structural analysis can be adopted for this complex behavior, such as limit analysis, pushover, or nonlinear dynamic analysis.Aiming to evaluate the capabilities of different approaches to similar problems, blind predictions were made using different approaches. For this purpose, two idealized structures were tested on a shaking table and several experts on masonry structures were invited to present blind predictions on the response of the structures, aiming at evaluating the available tools for the out-of-plane assessment of masonry structures. This article presents the results of the blind test predictions and the comparison with the experimental results, namely in terms of formed collapsed mechanisms and control outputs (PGA or maximum displacements), taking into account the selected tools to perform the analysis. 相似文献
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Simn Pedro Izcara Palacios 《对极》2019,51(4):1210-1230
Based on a qualitative methodology that includes in‐depth interviews conducted between 2008 and 2017 with 180 migrant smugglers from Mexico, the objective of this paper is to analyse the way US employers' interest in having access to cheap labour feeds migrant smuggling, and is connected to corruption in US border enforcement. We conclude that corruption on the US side of the border could be systematic and not a matter of a few bad apples. Corruption is manifested in selective enforcement, which is a pragmatic practice that justifies enhanced immigration enforcement, and benefits US immigration agents, US employers and Mexican smugglers, while undocumented border crossers suffer the monstrous effects of militarised border enforcement. 相似文献
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Alexandre Oliveira Tavares Mário Monteiro Pedro Pinto Santos 《European Planning Studies》2019,27(7):1432-1459
Small and medium-sized cities represent the backbone of the European territory, promoting cohesion and an economic base for development. The study compares the spatial and temporal trajectories of land use in three small/medium-sized cities located in central Portugal, between 1958 and 2011. The cities of Viseu, Leiria and Castelo Branco were chosen because they are located in different urban sub-systems and because of the different factors that frame their alterations in land use, occupation and consequent urban development. The research evaluates the transformations, supported by indicators to explain the spatial dynamics of losses and gains and a principal component analysis compares the land-use trajectories for the three cities. The general results reveal an increase from the central part of the study areas to the periphery, contrasting with a continuous decrease of the agricultural parts, illustrating peri-urbanization and rururbanization processes. The study allows identification of the dynamics in the three analysed areas, highlighting the different rhythms of change and relating them to the particularities that exist in each city. The methodology represents an advantage for the analysis and evaluation of territorial dynamics related to land-use change, and made possible the identification of the different forces. 相似文献
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Paula Pinto Costa 《Scandinavian journal of history》2016,41(2):141-159
Military orders have historically played a key role in defining borders, both in a mental sense, by favouring an awareness of alterity in the most peripheral territories (Christians against Muslims and Christians against Pagans), and also in more direct ways, as owners of land in these territories. This article1 discusses both the influence, in the broadest sense, of territory and periphery upon the medieval military orders, and the relationship between the crown and the military orders. It will be done through a comparative historical analysis of two cases: Portugal and Denmark in the 12th–16th centuries. Both countries were placed at the periphery of the Western world in the Middle Ages, and they were both active agents in the Crusading movement. 相似文献
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Luís Espinha da Silveira Daniel Alves Marco Painho Ana Cristina Costa Ana Alcântara 《Historical methods》2013,46(3):157-174
Abstract Surpassing the national perspective usually adopted, the authors confirmed the existence of a pattern of population distribution common to the whole Iberian Peninsula in the long run. This pattern is clearly associated with geographical factors. These variables seem to have more weight in explaining changes between 1877/78 and 1940 than in the period from 1940 to 2001. The observation of the cross-border region has shown that proximity to the frontier has not generated any distinct pattern of population density on either side of the boundary line. The spatial coherence of the observed phenomena throughout the Peninsula and of its evolution, independent of the border between states, reinforces the importance of geographic factors in their explanation. At the same time, this verification opens up new issues related to the effect of national political and economic policies. 相似文献
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Igor Gutiérrez-Zugasti David Cuenca-Solana Pedro Rasines del Río Emilio Muñoz Silvia Santamaría José M. Morlote 《Journal of Anthropological Archaeology》2013
The role of coastal resources in the subsistence strategies of Palaeolithic human populations has only recently become an important topic in Old World archaeology. Information on the exploitation of these resources, both as foodstuffs and symbolic elements, can be used to infer the emergence of modern human behaviour as well as to track the diversification and intensification of human diet over time. The excavations carried out at El Cuco rockshelter, located in northern Spain have provided evidence for the exploitation of marine resources during the Early Upper Palaeolithic. The accumulation of Patella shells at El Cuco provides the largest accumulation and the first clear evidence of collection and consumption of molluscs during the Aurignacian on the Atlantic Façade of Europe. A deposit of ornamental shells appeared in a very homogeneous context dated to the Gravettian, suggesting that the shells belonged to the same item. The analysis of this evidence has allowed us to conclude that marine resources were systematically used at least from the beginning of the Upper Palaeolithic in the region. However, a comparison with the Mesolithic shows that intensive shellfish gathering did not occur until the end of the Upper Palaeolithic. Regarding the ornaments, it is interpreted that the identified shell beads were used as social or personal status markers. 相似文献