Stabilization of the Tlaltecuhtli monolith pigments

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.     

Romita pottery revisited: a reassessment of the provenance of ceramics from Colonial Mexico by LA-MC-ICP-MS

The origin of Romita pottery has been a controversial topic during the last three decades of Colonial Mexico archaeological studies. Lead isotopic analyses of glaze coatings of Spanish and Mexican pottery, and Romita ceramics unearthed from the archaeological site of the Metropolitan Cathedral in Mexico City provide evidence that support a Mexican origin.     

The spatial distribution of population in Spain: An anomaly in European perspective

We exploit the GEOSTAT 2011 population grid with a very high 1 km² resolution to document that Spain presents the lowest density of settlements among European countries. Only a small fraction of the Spanish territory is inhabited, particularly in its southern half, which goes hand in hand with a high degree of population concentration. We uncover through standard regression analysis and spatial regression discontinuity that this anomaly cannot be accounted for by adverse geographic and climatic conditions. The second part of the paper takes a historical perspective on Spain's settlement patterns by showing that the spatial distribution of the population has been very persistent in the last two centuries, and that the abnormally low density of settlements with respect to European neighbors was already visible in the 19th century, which indicates that this phenomenon has not emerged recently as a consequence of the transformations associated with industrialization and tertiarization. Using data on ancient sites, we find that Spain did not feature scarcity of settlements in comparison to other countries in premedieval times, suggesting that its current anomalous settlement pattern has not always existed and is, therefore, not intrinsic to its geography.     

On the Evolution of Relative Prices and Its Nature at the Regional Level: The Case of Spain

This paper studies the relevance and nature of shifts in relative prices at the regional level in Spain. Deviations in relative prices tend to be small (at most half a point of inflation annually) but persistent. They are determined by features intrinsic to deep economic integration, in particular, wage mechanisms operating at the national level. This is in stark contrast to evidence at the international level. Therefore, while acknowledging that divergent price evolutions are possible in the European Monetary Union, their nature will be different from those observed among Spanish regions.     

Computer vision methods and rock art: towards a digital detection of pigments

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.     

Trade,tribute, and neutron activation: The colonial political economy of Xaltocan,Mexico

In Trade, Tribute, and Transportation, Ross Hassig argues that indigenous towns in the northern Basin of Mexico during the colonial period were largely self-sufficient. They traded with Mexico City mostly in elite goods, but for the most part they produced for their own subsistence or traded with nearby towns. Chemical characterization by instrumental neutron activation analysis (INAA) and portable X-ray fluorescence (pXRF) of ceramics and obsidian from post-conquest contexts in Xaltocan, a site in the northern Basin of Mexico, reveals that Hassig’s model is partly correct for describing Xaltocan. The town focused on trade with nearby towns and it produced some ceramics for local consumption. However, Xaltocan was hardly isolated and self-sufficient in the post-conquest period. Instead, the data suggest that the people of Xaltocan also obtained ceramics and obsidian from a greater variety of sources than under Aztec domination. Rather than being an isolated rural site, Xaltocan either increased its external connections and number of trading partners after the Spanish conquest, or it managed to obtain a greater variety of products than before through a bustling market system.     

Regional Externalities And Growth: Evidence From European Regions*

Abstract. This paper models externalities of production across regional economies. Under the assumption that knowledge diffuses without political or administrative barriers, we derive externalities that affect the steady state and the process of growth of each economy. The empirical counterpart of the reduced form equation summarizing the process of growth allows us to test for the presence of regional spillovers and to measure their magnitude. Our results for a sample of European regions show that spillovers are far from negligible, are robust to the consideration of variables within each region, and may cause nondecreasing returns at the spatial aggregate level. The paper also relates previous empirical evidence on spatial dependence in growth studies to the externalities modeled here.