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This paper provides new information about the social structure of the Late Classic (ad 600–800) Maya by using stable isotope analysis to analyze dietary practices and migration histories of 22 elite individuals from three residential compounds at the archaeological site of Chinikiha in Chiapas, Mexico. The research assess whether intra-elite social differentiation was practiced through consumptive practices and simultaneously explores residential histories of individuals in the sample. Diet is determined by carbon- and nitrogen-stable isotope analysis of both bones and teeth; residential mobility is studied by stable oxygen isotope analysis. The results find no significant differences in stable isotope values between the sexes, between residential compounds, or between individuals with different burial treatments. However, children may have had diets with higher maize consumption than adults. Additionally, three individuals with childhood locations outside of Chinikiha are identified. This study contributes a nuanced understanding of the social structure of the ancient Maya elite, and at least in the case of Chinikiha, suggests minimal intra-household status differentiation in terms of diet.

This study examines the diet consumed by the population at the neighborhood center of Teopancazco, Teotihuacan, in the basin of Mexico. We used stable isotope analysis of δ13C and δ15N of the dentine collagen as well as the δ13C from enamel bioapatite from teeth (M2 and M3) of 39 of excavated burials. The results show that the diet consumed by the majority of the population during childhood and adolescence had high 13C enriched values in both dietary components: δ13C enamel_bioapatite = −2.0 ‰ ± 1.5 for the whole diet and δ13C dentine_collagen = − 9.4 ‰ ± 2.1 for the protein component. According to the bi-variable and multivariable models, some individuals consumed higher amounts of C4/CAM resources than those specified in cluster #2 (70 % C4 diet; ≥50 % C4/CAM protein). An inter-tissue adjustment of 2.3 ‰ was used to relate the enamel bioapatite data to the bone bioapatite of the models. Average δ15Ndentine_collagen was 10.2 ‰ ± 2.8 with high variability especially for four individuals, three of which belong to special burials, suggesting different access to meat or marine products due to their social or migration status and/or to pathological conditions. The data suggest that maize was the staple crop of the population not only at Teopancazco but for Teotihuacan as a whole, in the form of tortillas, tamales, atole, and protein from maize-fed animals with the inclusion of other CAM, C4, and C3 resources probably from the bountiful ecosystem of the basin of Mexico or from the wide trade system that Teotihuacan had with Mesoamerica.

In this paper we introduce the notion of orthogonality for arbitrary families of elements of a partial abelian monoid, we study uniform semigroup valued measures on a partial abelian monoid, and we establish interesting results about the existence of the support of such measures.

Let (X, F) be an Alexandroff space, let A(F) be the Boolean subalgebra of 2X generated by F, let G be a Hausdorff commutative topological lattice group and let rbaF(A(F), G) denote the set of all order bounded F-inner regular finitely additive set functions from A(F) into G. Using some special properties of the elements of rbaF(A(F), G), we extend to this setting the first decomposition theorem of Alexandroff.

Carbon stable isotope ratios were determined in dominant biotic components of pelagic and littoral systems in Alchichica crater-lake. Results showed that carbon signatures were significantly different between both systems. The pelagic environment was more depleted (−26.15 to −15.14 per mille) than the littoral zone (−21.03 to −17.91 per mille). The potential source end-point in the simplified pelagic community was established to be diatomaceous phytoplankton; its predicted value was −21.7 per mille. There is a clear evidence thatNodularia does not sustain the pelagic food chain. In contrast, the highly diverse littoral community was sustained by epiphytes. No allochthonous sources seemed to influence this food web.13C enrichment was observed along the components of both systems with fractionations of 0.8 to 1.4 per mille. The contribution of the seagrassRuppia maritima is probably associated with the detritus pathway. Carbon source partitioning between both systems was not recorded. The δ13C in Alchichica crater-lake was more enriched than in other saline lakes and could be attributed to different salinity and CO2 concentrations among lakes.

On a global basis, nearly 42% of tropical land area is classified as tropical deciduous forest (TDF) (Murphy and Lugo 1986). Currently, this ecosystem has very high deforestation rates; and its conversion to cattle pasture may result in losses of soil organic matter, decreases in soil fertility, and increases in CO2 flux to the atmosphere. The soil organic matter turnover rate in a TDF after pasture conversion was estimated in Mexico by determining natural abundances of13C. Changes in these values would be induced by vegetation changes from the C3 (forest) to the C4 (pasture) photosynthetic pathway. The rate of loss of remnant forest-soil organic matter (fSOM) was 2.9 t ha-1 year-1 in 7-year-old pasture and decreased to 0.66 t ha-1 year-1 by year 11. For up to 3 years, net fSOM level increased in pastures; this increment can be attributed to decomposition of remnant forest roots. The sand-associated SOM fraction was the most and the silt-associated fraction the least depleted. TDF conversion to pasture results in extremely high rates of loss of remnant fSOM that are higher than any reported for any tropical forest.