Instrumental neutron activation analysis of postclassic and historic-period pottery from Soconusco, Chiapas, Mexico [abstract]

Abstract only availableThe study involved utilizing Instrumental Neutron Activation Analysis (INAA) at the University of Missouri Research Reactor (MURR) on 96 pottery samples from the post-classic Mayan (ca. 1000-1500 C.E.) and historic eras excavated from the Soconusco region of Southern Chiapas, Mexico. This was done in order to understand and map the long-distance trade networks of Mesoamerica via the unique chemical characteristics of pottery. The samples were irradiated according to MURR procedures and measured at specific intervals on a gamma-ray spectrometer to yield the relative concentration of elemental composition. The data obtained from the use of INAA has allowed for the creation of compositional groups according to the chemical signatures of the pottery. These groups were then compared with other compositional reference groups from throughout Mesoamerica accumulated within the MURR archives. The results indicate a complex and diverse trade relationship with post-classic pottery dominated by samples produced either locally or in the surrounding Chiapas, and historic pottery being imported across Mexico from Colonial New Spawn sites such as Puebla, Mexico City and perhaps as yet un-identified production centers. It is hoped that an increase in further comparative data will help in the locating of these additional pottery production centers. From these results, this study seeks to add greater depth to the discussion of inter-regional trade systems across Mesoamerica in both the post-classic and historic periods and enhance the conclusions drawn from those discussions

LA-ICP-MS Analysis of Quartzite from the Upper Gunnison Basin, Colorado

We report the results of LA-ICP-MS analysis of 402 quartzite samples representing 48 collection loci in the Upper Gunnison Basin (UGB), Colorado and determine the extent to which the sources can be geochemically discriminated from one another using this non-destructive technique. The ability to differentiate among the sources would open the door to provenance studies of the quartzite chipped-stone tools and debitage that constitute 95% or more of most of the 3000-plus prehistoric site assemblages documented in the UGB. Our samples represent prehistorically quarried and non-quarried quartzite sources, including outcrop (primary) and gravel (secondary) deposits. The results reveal spatial and chronological trends in quartzite elemental composition that can be exploited for provenance determinations of quartzite artifacts from UGB sites, albeit using an assemblage-based sourcing strategy that differs from the familiar approach of “matching” obsidian artifacts to their statistically likeliest geological source. We offer a preliminary version of a sourcing protocol for UGB quartzite

La producción de sal en el sitio Gallo encantado (GE1), Chiapas, México: análisis de la tecnología cerámica desde la arqueología evolutiva

This piece of research focuses on salt production during the Preclassic and late Postclassic periods in Gallo encantado (GE1). Using the theory of the evolution of ceramic traditions, a proposal was developed taking into account the stylistic and functional attributes portrayed by ceramics in order to define the differences between these two periods. The findings emerging from a direct comparison of frequency indicate that the attributes displayed by these ceramics characterize both periods and may have contributed to improve the salt production process. These functional improvements make it possible to understand the presence of that form of specialization in both the Preclassic and the Late Postclassic periods. Based on this interpretation, it can be inferred that the higher demand observed during the Preclassic period and the intensification of trade during the Late Postclassic period were the driving forces behind this specialization in ceramics.La investigación se enfoca en la producción de sal de los periodos Preclásico y Posclásico Tardío, en el sitio Gallo encantado (GE1). Al usar la teoría de la evolución cerámica se modeló una propuesta que toma en cuenta los atributos estilísticos y funcionales de la cerámica para determinar las diferencias entre los dos periodos. Los resultados de la comparación directa de frecuencias indican que los atributos de estas cerámicas estuvieron presentes en ambos periodos y habrían contribuido a mejorar el proceso de producción de sal. Estas mejoras funcionales permiten interpretar que la especialización estuvo presente tanto en el Preclásico como en el Posclásico Tardío. A partir de ello, se infiere que la mayor demanda observada durante el Preclásico y la intensificación del comercio en el periodo Posclásico Tardío fueron las fuerzas impulsoras de esta especialización cerámica

Identifying drivers of forest resilience in long-term records from the Neotropics

Here, we use 30 long-term, high-resolution palaeoecological records from Mexico, Central and South America to address two hypotheses regarding possible drivers of resilience in tropical forests as measured in terms of recovery rates from previous disturbances. First, we hypothesize that faster recovery rates are associated with regions of higher biodiversity, as suggested by the insurance hypothesis. And second, that resilience is due to intrinsic abiotic factors that are location specific, thus regions presently displaying resilience in terms of persistence to current climatic disturbances should also show higher recovery rates in the past. To test these hypotheses, we applied a threshold approach to identify past disturbances to forests within each sequence. We then compared the recovery rates to these events with pollen richness before the event. We also compared recovery rates of each site with a measure of present resilience in the region as demonstrated by measuring global vegetation persistence to climatic perturbations using satellite imagery. Preliminary results indeed show a positive relationship between pre-disturbance taxonomic richness and faster recovery rates. However, there is less evidence to support the concept that resilience is intrinsic to a region; patterns of resilience apparent in ecosystems presently are not necessarily conservative through time

Oral abstracts of the 21st International AIDS Conference 18-22 July 2016, Durban, South Africa

The rate at which HIV-1 infected individuals progress to AIDS is highly variable and impacted by T cell immunity. CD8 T cell inhibitory molecules are up-regulated in HIV-1 infection and associate with immune dysfunction. We evaluated participants (n=122) recruited to the SPARTAC randomised clinical trial to determine whether CD8 T cell exhaustion markers PD-1, Lag-3 and Tim-3 were associated with immune activation and disease progression.Expression of PD-1, Tim-3, Lag-3 and CD38 on CD8 T cells from the closest pre-therapy time-point to seroconversion was measured by flow cytometry, and correlated with surrogate markers of HIV-1 disease (HIV-1 plasma viral load (pVL) and CD4 T cell count) and the trial endpoint (time to CD4 count <350 cells/μl or initiation of antiretroviral therapy). To explore the functional significance of these markers, co-expression of Eomes, T-bet and CD39 was assessed.Expression of PD-1 on CD8 and CD38 CD8 T cells correlated with pVL and CD4 count at baseline, and predicted time to the trial endpoint. Lag-3 expression was associated with pVL but not CD4 count. For all exhaustion markers, expression of CD38 on CD8 T cells increased the strength of associations. In Cox models, progression to the trial endpoint was most marked for PD-1/CD38 co-expressing cells, with evidence for a stronger effect within 12 weeks from confirmed diagnosis of PHI. The effect of PD-1 and Lag-3 expression on CD8 T cells retained statistical significance in Cox proportional hazards models including antiretroviral therapy and CD4 count, but not pVL as co-variants.Expression of ‘exhaustion’ or ‘immune checkpoint’ markers in early HIV-1 infection is associated with clinical progression and is impacted by immune activation and the duration of infection. New markers to identify exhausted T cells and novel interventions to reverse exhaustion may inform the development of novel immunotherapeutic approaches

Characterizing the Stoneware "Dragon Jars" in the Guthe Collection: Chemical, Decorative, and Formal Patterning

This paper presents a multifaceted study of a collection of stoneware ceramic vessels in the Guthe Collection of the Museum of Anthropology, University of Michigan. These vessels, recovered in the Philippines but manufactured in multiple production sites across East and Southeast Asia, provide insights into premodern economic interactions and maritime trade. Our study of this collection drew on multiple approaches to identify coherent groupings of vessels associated with locations and traditions of production. These include instrumental neutron activation analysis (INAA) of pastes; laser ablation inductively coupled plasma mass spectrometry (LAICP- MS) of glazes; stylistic analysis of decorative motifs and their execution; and study of morphological attributes. Results of our analyses point to at least four production areas for these ubiquitous trade wares and lay the groundwork for future research on Southeast Asian l1uritime trade from the twelfth through nineteenth centuries A.D. KEYWORDS: Southeast Asia, ceramic classification, trade wares, dragon jars

EVOLUTION OF THE MESOAMERICAN MOTHER CULTURE

AbstractAn ongoing debate about Early Formative cultural elaboration in Mesoamerica is based largely on claims about where innovations originated and when different regions influenced each other. One view is that Gulf lowland populations called “Olmec” by archaeologists made a number of key innovations and that their influence on contemporary societies stimulated the rise of Mesoamerican civilization. Another view is that multiple regions participated equally and all made innovations that became the legacy of later Mesoamerican societies. Additional empirical work will help resolve some of the issues raised by this debate, as Cheetham and Blomster (2010) have recently suggested in this journal. Explicit theory can also help move the discussion forward.</jats:p