Ideología y Poder en el Arte del Manejo Antiguo del Agua

The temples and monuments of Copan are replete with symbols of water and sustenance, both important forces in the development of social complexity throughout the region and prevalent in Mesoamerica. Our work reveals that the water systems managed in Copan and neighboring regions of Honduras have a long history and they manifest in diverse forms. Besides their functional utilization, from irrigation to water storage, water sources and systems had numerous religious uses. We will discuss how water was conceived, used and represented in ancient times as well as we believe its sacred character was utilized in art to elevate political authority. From our research we know that communal organization was important to the successful management of ancient water systems. It might be that some of those methods are relevant to improve life conditions in current landscapes, to assure potable water and improve harvests.Los templos y monumentos de Copán están repletos de símbolos del agua y de sustento, ambas fuerzas importantes en el desarrollo de complejidad social a través de la región y prevalente en toda Mesoamérica. Nuestro trabajo revela que los sistemas de agua manejados en Copán y áreas circundantes de Honduras tienen una historia larga y se manifiestan en diversas formas. Además de funciones prácticas, desde irrigación hasta el almacenamiento de agua, las fuentes y sistemas de agua tenían numerosos usos religiosos. Discutiremos cómo se concebía, usaba y se representaba el agua en tiempos antiguos y las formas que en que creemos se utilizaba su carácter sagrado en el arte para elevar la autoridad política. Por medio de nuestras investigaciones sabemos que la organización comunitaria era importante para la operación exitosa del manejo de los sistemas antiguos de agua. Puede que algunos de estos métodos sean relevantes en los paisajes actuales para mejorar las condiciones de vida, asegurar la potabilidad del agua y mejorar las cosechas

Mathematical Model of Easter Island Society Collapse

In this paper we consider a mathematical model for the evolution and collapse of the Easter Island society, starting from the fifth century until the last period of the society collapse (fifteen century). Based on historical reports, the available primary sources consisted almost exclusively on the trees. We describe the inhabitants and the resources as an isolated system and both considered as dynamic variables. A mathematical analysis about why the structure of the Easter Island community collapse is performed. In particular, we analyze the critical values of the fundamental parameters driving the interaction humans-environment and consequently leading to the collapse. The technological parameter, quantifying the exploitation of the resources, is calculated and applied to the case of other extinguished civilization (Cop\'an Maya) confirming, with a sufficiently precise estimation, the consistency of the adopted model.Comment: 9 pages, 1 figure, final version published on EuroPhysics Letter

Nothing Lasts Forever: Environmental Discourses on the Collapse of Past Societies

The study of the collapse of past societies raises many questions for the theory and practice of archaeology. Interest in collapse extends as well into the natural sciences and environmental and sustainability policy. Despite a range of approaches to collapse, the predominant paradigm is environmental collapse, which I argue obscures recognition of the dynamic role of social processes that lie at the heart of human communities. These environmental discourses, together with confusion over terminology and the concepts of collapse, have created widespread aporia about collapse and resulted in the creation of mixed messages about complex historical and social processes

Effect of Geometry on Thermoelastic Instability in Disk Brakes and Clutches

The finite element method is used to reduce the problem of thermoelastic instability (TEI) Introduction The frictional heat generated during sliding causes thermoelastic expansion that affects the distribution of contact pressure. The resulting thermomechanical feedback is unstable if the sliding speed is sufficiently high, leading to the development of non-uniform contact pressure and local high temperatures known as "hot spots." This non-uniformity also tends to cause a low frequency vibration known in the automotive disk brake community as "hot roughness" or "hot judder." This is a significant source of customer warranty claims and has resulted in an increased interest in the subject in recent years The mechanism of thermoelastic instability or "TEI" was first explained by These idealized treatments provide a useful indication of the nature of the phenomenon and the effect of material properties on the critical speed, but the predicted critical speeds are typically significantly higher than those observed experimentally. A significant step towards explaining this discrepancy was made b

Reliable AMS ages for Mayan Caches at Copán, Honduras based on spondylus sp. marine shells

Copán, located in western Honduras, is one of the most well-known of all ancient Mayan cities. Over a century of intensive archaeological research has revealed the development of Copán from its origins as a small agricultural village, to a major city state, followed by its decline or ‘collapse’ after AD 800. Copán’s chronology relies heavily on changes in ceramics dated by association with hieroglyphic dates on monuments. There are surprisingly few radiocarbon dates available for a site with such a long-term history of study and researchers have expressed a general reluctance to use radiocarbon dating (mainly on charcoal) at Copán because radiocarbon ages are often too old compared to associated hieroglyphic dates. Dating marine shell offers an alternative approach for radiocarbon-based chronology building at Copán. Spondylus sp. or spiny oyster shell is found in offering caches throughout the Copán valley. Caches are commonly associated with the dedication of buildings, altars and stelae. We have dated cached Spondylus sp. shells and compared their ages with calendrical dates derived from Maya hieroglyphs to obtain new information about Classic Maya caching behaviours and the chronology of contact with exchange partners in coastal areas from where the shell was sourced. A total of 17 Spondylus sp. shells collected from 9 independently dated contexts were analysed for 14C with AMS to high precision (0.30-0.35%) using the facilities at ANSTO and Waikato. Most of our AMS dates agreed well with structural/hieroglyphic dates indicating that Spondylus sp. can be reliably used for dating contexts. The results also showed there was very little time between death of the shellfish and placement within caches suggesting that shells may have been acquired for specific caching/dedication events rather than stored for long periods