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

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

Englerin A Selectively Induces Necrosis in Human Renal Cancer Cells

<div><p>The number of renal cancers has increased over the last ten years and patient survival in advanced stages remains very poor. Therefore, new therapeutic approaches for renal cancer are essential. Englerin A is a natural product with a very potent and selective cytotoxicity against renal cancer cells. This makes it a promising drug candidate that may improve current treatment standards for patients with renal cancers in all stages. However, little is known about englerin A's mode of action in targeting specifically renal cancer cells. Our study is the first to investigate the biological mechanism of englerin A action in detail. We report that englerin A is specific for renal tumor cells and does not affect normal kidney cells. We find that englerin A treatment induces necrotic cell death in renal cancer cells but not in normal kidney cells. We further show that autophagic and pyroptotic proteins are unaffected by the compound and that necrotic signaling in these cells coincided with production of reactive oxygen species and calcium influx into the cytoplasm. As the first study to analyze the biological effects of englerin A, our work provides an important basis for the evaluation and validation of the compound's use as an anti-tumor drug. It also provides a context in which to identify the specific target or targets of englerin A in renal cancer cells.</p> </div

Englerin A does not induce cleavage of caspase 3, PARP, caspase 1 or the autophagic markers LC-3 and Beclin-1.

<p>Cells were treated with either 1 μM englerin A, carrier DMSO or 5 μM staurosporine for the indicated amount of time. (A) After the incubation, cells were lysed and lysates were analyzed by immunoblotting for PARP cleavage or full-length and cleaved caspase 3 (Casp3-fl, Casp3-cl). Equal protein loading was confirmed by probing for GAPDH. Full-length and cleaved bands are indicated. The experiment was repeated three times. (B) Alternatively, after incubation cells were lysed and caspase 3 activity was tested using a caspase 3 activity assay kit. Values shown are means ± SEM (n = 6), statistically significant differences are marked with asterisks (*** p<0.001). (C) Cells were treated with either 1 μM englerin A, carrier DMSO for 60min or 50 μM chloroquine diphosphate (Chloro) for 18 h. After the incubation, cells were lysed and lysates were analyzed by immunoblotting for Beclin-1, LC3-I/II and caspase 1 cleavage (proenzyme p45 and cleaved active subunit p20). Equal protein loading was confirmed by probing for GAPDH. All membranes were analyzed using IRDye secondary antibodies and a Licor Odyssey system. Membranes shown are from representative experiments.</p

Englerin A induces production of reactive oxygen species and increased concentration of intracellular Ca²⁺.

<p>(A) Cells were treated with either 1 μM englerin A or carrier DMSO for 60 min. The relative change in reactive oxygen (ROS) or reactive nitrogen species (RNS) compared to cells treated with the carrier DMSO was measured using the Total ROS detection kit. Histograms show fluorescence intensities in a representative experiment (left panel). Quantified relative changes in ROS/RNS shown (right panel) are means ± SEM (n = 5), statistically significant differences are marked with asterisks (* p<0.05). (B) Cells were treated with either 1 μM englerin A or carrier DMSO for 60 min, or 10 μM ionomycin for 50 min. Fluo-3 binding to Ca²⁺ ions was measured through an increased fluorescence emission of the dye at 520 nm upon excitation at 485 nm. Histograms show fluorescence intensities in a representative experiment (left panel). Quantified relative changes in intracellular calcium ions shown (right panel) are means ± SEM (n = 3), statistically significant differences are marked with asterisks (* p<0.05, *** p<0.001).</p

Englerin A selectively reduces cell viability in renal cancer cells.

<p>(A) Chemical Structure of englerin A. (B) Glioblastoma (SF-295), normal immortalized kidney cells (HEK-293), renal proximal tubule cells (RPTC) and renal cancer cells (UO-31, A-498) were incubated with the indicated concentration of englerin A for 48 h. Cell viability was analyzed using an XTT Cell Proliferation Assay. Results are shown in % viability compared to a cell sample treated with the carrier DMSO. Values shown represent the mean ± SEM of all experiments (n≥6). IC50 values were calculated with Prism 5 using a non-linear regression fit (log(inhibitor) vs. normalized response – variable slope).</p