Analysis of the Preserved Amino Acid Bias in Peptide Profiles of Iron Age Teeth from a Tropical Environment Enable Sexing of Individuals Using Amelogenin MRM.

The first dental proteomic profile of Iron Age individuals (ca. 2000-1000 years B.P.), collected from the site of Long Long Rak rock shelter in northwest Thailand is described. A bias toward the preservation of the positively charged aromatic, and polar amino acids is observed. It is evident that the 212 proteins identified (2 peptide, FDR <1%) comprise a palimpsest of alterations that occurred both ante-mortem and post-mortem. Conservation of amino acids within the taphonomically resistant crystalline matrix enabled the identification of both X and Y chromosome linked amelogenin peptides. A novel multiple reaction monitoring method using the sex specific amelogenin protein isoforms is described and indicate the teeth are of male origin. Functional analysis shows an enrichment of pathways associated with metabolic disorders and shows a capacity for harboring these conditions prior to death. Stable isotope analysis using carbon isotopes highlights the strongly C3 based (≈80%) diet of the Long Long Rak cemetery people, which probably comprised rice combined with protein from freshwater fish among other food items. The combination of proteomics and stable isotope analysis provides a complementary strategy for assessing the demography, diet, lifestyle, and possible diseases experienced by ancient populations.

Direct stable isotope porewater equilibration and identification of groundwater processes in heterogeneous sedimentary rock.

The off-axis integrated cavity output spectrometry (ICOS) method to analyse porewater isotopic composition has been successfully applied over the last decade in groundwater studies. This paper applies the off-axis ICOS method to analyse the porewater isotopic composition, attempts to use the isotopic shift in groundwater values along with simple geochemical mixing model to define the groundwater processes in the Sydney Basin, Australia. Complementary data included geophysical, hydrogeological, geochemical, and mineralogical investigations. Porewater from core samples were analysed for δ(18)O and δ(2)H from various sedimentary units in the Basin and compared to endpoint water members. Stable δ(18)O and δ(2)H values of porewaters in the Basin (-9.5 to 2.8‰ for δ(18)O and -41.9 to 7.9‰ for δ(2)H) covered a relatively narrow range in values. The variability in water isotopes reflects the variability of the input signal, which is the synoptic variability in isotopic composition of rainfall, and to a minor extent the subsequent evaporation. The porosity, bulk density and mineralogy data demonstrate the heterogeneity that adds the complexity to variations in the isotope profile with depth. The source of chloride in the sedimentary sequence was related to rock-water and cement/matrix-water interaction rather than to evaporation. The heterogeneous character of the sedimentary rock strata was supported by a change in pore pressures between units, density and variability in rock geochemical analyses obtained by using X-ray fluorescence (XRF) and X-ray power diffraction analyses. This research identified distinct hydrogeological zones in the Basin that were not previously defined by classic hydrogeological investigations. Isotopic signature of porewaters along the detailed vertical profile in combination with mineralogical, geochemical, geophysical and hydrogeological methods can provide useful information on groundwater movement in deep sedimentary environments. The findings of the study are valuable in management of sensitive ecosystems and potable resources above mining areas.

An oil spill surveillance program for Lake Pontchartrain.

This article describes an oil spill surveillance strategy implemented in response to BP's 2010 MC252 oil well blowout in the Gulf of Mexico. A three-pronged strategy consisted of Geographic Information System (GIS) monitoring of the surface slick, hydrodynamic modeling of the potential movement of the slick within the Basin, and weekly field reconnaissance. Our analysis was completed in near real time during the event and the results and predictions helped local responders minimize oiling impacts in Lake Pontchartrain. No prior planning was undertaken before this crisis response, and this article reports our support activities as they happened. For the GIS component, a remote sensing derived surface slick outline layer was obtained to produce near daily maps showing the slick's proximity to Lake Pontchartrain along with weather conditions and deployed response assets. This regular monitoring of the slicks' location was complemented by hydrodynamic numerical modeling that simulated the currents that determined the trajectories of oil particles. These data were ground-truthed through weekly reconnaissance trips that assessed the potential routes of oil penetration into Lake Pontchartrain for the presence of sheen, tarballs, and other oil constituents. Despite the ad hoc design and on-the-fly implementation, these three assessments provided consistent and actionable information.