Esta es una síntesis de las principales características organizativas de la secuencia de explotación de la obsidiana verde del yacimiento de La Sierra de Las Navajas (Pachuca), de las culturas teotihuacana, tolteca y azteca. El uso de este vidrio volcánico se relaciona directamente con el desarrollo económico, militar, religioso y comercial de las organizaciones estatales del centro de Mesoamérica. En cada etapa cultural, identificamos los principales procesos de manufactura de instrumentos, armas y objetos religiosos en los talleres del yacimiento, así como la permanencia de los mineros, talladores y cargadores. El análisis diacrónico de la organización de la explotación y la distribución de la obsidiana verde con el desarrollo de la sociedad, nos permite detectar los cambios substanciales en la estrategía de obtención de esta importante materia prima.
Se presentan los primeros resultados del análisis fisicoquímico de mezclas pigmentarias rojas y blancas empleadas en la decoración de cerámicas arqueológicas provenientes de sitios localizados en la cuenca media y baja del río Paraná (provincia de Entre Ríos, nordeste de Argentina). El material analizado corresponde a conjuntos cerámicos asociados a grupos Goya-Malabrigo, cronológicamente situados al final del Holoceno Tardío. Se utiliza la técnica MEB-EDX a fin de aportar datos relativos a la caracterización elemental de las pinturas, en su fracción inorgánica. La información obtenida señala altas concentraciones de Fe en las pinturas rojas, en tanto que aquellas blancas muestran cierta variabilidad en su composición, destacándose niveles elevados de Ca y P. Estos resultados constituyen un punto de partida para discutir las elecciones tecnológicas de estos grupos en relación con las preparaciones pigmentarias.Palabras clave: mezclas pigmentarias, análisis MEB-EDX, cerámica Goya-Malabrigo, cuenca del río Paraná, Holoceno Tardío
This paper presents the initial results of the physical-chemical analysis of red and white pigment mixtures used to decorate archaeological ceramics found at sites in the middle and lower Paraná River basin (Entre Ríos province, Northeast Argentina
Frozen chicken products have been identified recently as a cause of salmonellosis. At least eight salmonellosis outbreaks from 1998 to 2008 have implicated undercooked frozen chicken nuggets, strips, and entrees as infection vehicles. Thus, the presence of Salmonella in frozen products may pose an infection risk if the product is improperly cooked. The objective of this study was to assess the survivability of Salmonella during frozen storage (-20 degrees ) when inoculated in processed chicken products. Four Salmonella strains originally isolated from poultry were inoculated into frozen chicken nuggets (fully cooked) and frozen chicken strips (containing raw poultry) at initial populations of 10(4) to 10(5) CFU/g. Survival was assessed during storage at -20 degrees for 16 weeks by measuring bacterial growth on minimal, selective, and nonselective agars. Results indicate that cell populations measured in nonselective agars (plate count agar and plate count agar supplemented with tetracycline) and minimal (M9) agar remained relatively constant during the entire -20 degrees storage period studied (16 weeks) for both chicken nuggets and strips. However, cell populations were significantly (P < 0.05) lower when measured in selective agar (XLT4) during the 16 weeks of frozen storage for both chicken nuggets and strips, suggesting that these cells were structurally injured. The data presented in this study indicate that Salmonella can survive frozen storage when inoculated in frozen, processed chicken products and confirm that microbial counts on selective agar are not representative of the total population of samples subject to freezing.
Tubular pottery comprises certain peculiar artifacts that were produced by late Holocene complex hunter-gatherer societies in southeastern South America for unknown purposes. Some authors have related them to mortuary behaviour which has also been suggested by historical sources, while others have considered domestic use. In this paper, the technical, compositional and functional properties of these artifacts are explored in order to contrast both hypotheses, given an example of how technical analysis allows the identification of special pottery within archeological contexts. This analysis includes a study of the fabrics involved using low and high magnification, thin sections, Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Mössbauer Spectroscopy, Laser Induced Breakdown Spectroscopy and fatty acid profiles. The results show that these tubular artifacts are not fit structurally for utilitarian purposes and show no evidence of domestic use. Based on these results and on historical data, it can be postulated that they were used as part of mortuary rituals, thus becoming part of the select global group of pottery manufactured exclusively for mortuary purposes.
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