Urban Centrality: A Simple Index

This study introduces a new measure of urban centrality. The proposed urban centrality index (UCI) constitutes an extension to the spatial separation index. Urban structure should be more accurately analyzed when considering a centrality scale (varying from extreme monocentricity to extreme polycentricity) than when considering a binary variable (monocentric or polycentric). The proposed index controls for differences in size and shape of the geographic areas for which data are available, and can be calculated using different variables such as employment and population densities, or trip generation rates. The properties of the index are illustrated with simulated artificial data sets and are compared with other similar measures proposed in the existing literature. The index is then applied to the urban structure of four metropolitan areas: Pittsburgh and Los Angeles in the United States; São Paulo, Brazil; and Paris, France. The index is compared with other traditional spatial agglomeration measures, such as global and local Moran's I, and density gradient estimations. El presente estudio introduce una nueva medida de centralidad. El índice de centralidad urbana propuesto (UCI, por sus siglas en inglés) es una extensión al índice de separación espacial (spatial separation index)(Midelfart‐Knarvik et al. 2000). El análisis de la estructura urbana resulta más preciso al usar el índice cuando se toma en cuenta una escala de continua de centralidad (que puede variar de un monocentrismo extremo a un policentrismo extremo) que cuando se considera una variable binaria (monocéntrica o policéntrica). El índex propuesto controla las diferencias de tamaño y forma de las áreas geográficas de las que se tienen datos, y puede ser calculada utilizando diferentes variables, como empleo y densidad poblacional, o tasas de generación de viajes. Las propiedades del índice se ilustran con conjuntos de datos artificiales simulados, y se comparan con otras mediciones similares en la literatura ya existente. Posteriormente, el índice es aplicado a la estructura urbana de cuatro áreas metropolitanas: Pittsburgh y Los Ángeles, en EEUU; San Pablo, en Brasil; y París, Francia. Finalmente, se compara el índice con otras mediciones tradicionales de aglomeración espacial, como el índice de Moran local y global, y estimaciones de gradiente de densidad. 本文介绍了一种度量城市中心性的新方法,提出的城市中心性指数（UCI）是对空间分离指数的扩展。当涉及到中心性规模（从极单中心到极多中心）,不仅仅是二元变量（单中心或多中心）,城市结构则需更加精确的测度。本文构建的指数可以通过数据可获取的不同大小和形状的地理单元控制,并通过不同变量（如就业与人口密度或者旅次产生率）测算得到。该指数的属性可以通过人工数据集的模拟示例说明,或者通过对比已有文献对相似指数的阐述加以说明。然后,通过将该指数应用于全球四个大都市区（美国匹兹堡和洛杉矶、巴西圣保罗和法国巴黎）的城市结构中进行检验。最后,将该指数与其他测度传统空间集聚指数如全局和局部Moran指数及密度梯度估计进行对比.     

Seismic behavior of two Portuguese adobe buildings: Part I - in-plane cyclic testing of a full-scale adobe wall

This article addresses the laboratory testing of a full-scale double-T shaped adobe wall, under in-plane horizontal cyclic loading of increasing amplitude, with the aim of contributing to the understanding of the seismic behavior of adobe structures. The wall was built with lime adobes taken from an existing building and mortar with a traditional composition. The behavior of the wall was assessed in terms of: shear stress versus horizontal drift and moment versus rotation relationships; maximum lateral strength; drift and rotation at peak stress; evolution of stiffness, lateral displacements, dissipated energy, and natural frequency; and damage pattern. The wall exhibited brittle behavior and in-plane strength corresponding to 56% of the vertical load. Cracking was observed with an X-shaped pattern whereas no sliding occurred at its base. This research supported the subsequent development of a repair and retrofit solution and also of numerical models to simulate the seismic behavior of two adobe buildings.     

We will be known by the tracks we leave behind: Exotic lithic raw materials,mobility and social networking among the Côa Valley foragers (Portugal)

The aim of this study is to establish different socio-cultural models based on lithic raw material sourcing integrated with regional rock art distributions to infer social behaviours within the context of central Iberian Upper Palaeolithic societies. Specifically, we focus on Upper Palaeolithic hunter–gatherer mobility and social interaction in the Côa Valley. This study relies on a knowledge of regional geology and field work to identify the sources of the lithic raw material found at Côa Valley Upper Palaeolithic sites. We expose the context of use and discard of flint, which is naturally absent from the region, and other local materials. From this, we present a GIS based analysis concerning space, time and least-cost paths travelled. This analysis, along with the environmental data available, forms a baseline to evaluate different anthropological models on hunter–gatherer lithic use, mobility, and social networks. We conclude with a three-level model for social interaction, in the context of aggregation activities between different social meta-groups, which involves embedded procurement, long-distance raw material exchange, and symbolic community, reflected in the largest known open-air Upper Palaeolithic rock art concentration.     

Microstructures of Building Materials from Huaca De La Luna,Peru

ABSTRACT

The microstructures of building materials from the archaeological complex of Huaca de la Luna on the northern coast of Peru is assessed for the first time by a multiscale approach. The multiscale microstructural characterization used laboratory techniques including optical microscopy, scanning electron microscopy, X-ray microtomography, and both gas and powder pycnometry. Optical microscopy revealed the presence of organic matter and shell fragments and X-ray microtomography showed differences in the sizes and connectivity of pores. The BET (N₂ gas adsorption) specific surface areas showed greater presence of clayey matrix in the mortars. No significant differences among mortars and brick fragments mineralogy were detected by X-ray diffraction, so the larger amount of fine binding matrix in the mortars suggests that they were produced blending raw material with different grain sizes. The aim of this study is to provide data that can be used for a better understanding of the Moche culture, its construction techniques, and to support conservation strategies of the archaeological heritage.