Non-linear relationship between bulk δC and percent maize in carbonized cooking residues and the potential of false-negatives in detecting maize

Bulk δ¹³C values on charred cooking residues adhering to pottery sherd interior surfaces have been used as a source of information on the histories of maize in various locations in the western hemisphere. This approach is based on an assumption of a linear relationship between the percent maize in the resource mix cooked in a pot and δ¹³C. Previous experiments suggest that this relationship is non-linear, and maize may not be identified from bulk δ¹³C values even when it contributed substantially to the resource mix. A second round of experiments, presented here, indicates that the mobilization of carbon from maize and C₃ resources over time is the critical variable in residue formation and the resulting bulk δ¹³C value. This is influenced by the form of maize being cooked.     

Probing dietary change of the Kwädąy Dän Ts'ìnchį individual,an ancient glacier body from British Columbia: II. Deconvoluting whole skin and bone collagen δC values via carbon isotope analysis of individual amino acids

The remains of the Kwäd?y Dän Ts'ìnch? individual, a frozen male human, were recovered from a retreating glacier within the Tatshenshini-Alsek Park in British Columbia in August 1999. In order to provide information on both the geographical origin of this individual and low long he spent in the remote interior region prior to his death, molecular analysis and compound-specific carbon isotope analyses were performed on individual amino acids purified from his skin and bone. Gas chromatographic quantification of constituent amino acids of both tissues revealed a molecular distribution characteristic of collagen, dominated by glycine and to a lesser extent proline, hydroxyproline and alanine. Chiral gas chromatography indicated that protein preservation in both tissues was exceptional. Carbon isotope analysis of a faunal assemblage from an earlier prehistoric site from southern British Columbia provided reference dietary amino acid δ¹³C values for terrestrial (deer and domestic dog) and marine species (salmon and sealion), showing clear separation in all amino acids, particularly glycine which was extremely ¹³C-enriched in the marine animals. The distinction between terrestrial and marine organisms was increased by exploring Δ¹³C_{Glycine-Phenylalanine} values (6.6 ± 0.6‰ and 15.0 ± 2.1‰, respectively), which were higher in the latter by approximately 8‰, mirroring the increased δ¹⁵N_{Bulk collagen} values observed for the marine animals (R² = 0.78; p < 0.001). The Kwäd?y Dän Ts'ìnch? individual's bone had a similarly elevated Δ¹³C_{Glycine-Phenylalanine} value of 15.6 ± 1.0‰, indicating his extreme reliance on marine dietary resources throughout early life. The skin amino acid δ¹³C values were consistently lower than those observed for bone, with a concurrently lower Δ¹³C_{Glycine-Phenylalanine} value of 12.7 ± 0.9‰. The shift between the carbon isotope composition of bone (long-term diet) and skin amino acids (short-term diet) confirmed a sudden divergence away from marine food sources in the last months of life, consistent with his discovery 80 km inland.     

Adipocere withstands 1600 years of fluctuating groundwater levels in soil

An extraordinarily well-preserved skeleton of a child, interred in a stone sarcophagus in the Late-Roman era, was discovered in the city of Mainz (Germany) in 1998, covered with a puff pastry-like substance assumed to be adipocere. It is the first time that this substance, which is derived from fat under oxygen-deficient conditions and prevents corpses from decaying, has been discovered on corpses buried under conditions described in the present paper.     

S.C并非胡适笔名

1923年9月16日,<努力周报>发表署名S.C的文章<"大国民"的外交>.史学界认为该文是胡适所作,S,C是胡适笔名.实际上,从用语、思想观念及1923年9月前后胡适的居行及著述等方面考察,均可断定<"大国民"的外交>非胡适所作,S.C不是他的笔名.     

THE CHRONOSTRATIGRAPHY AND GEOARCHAEOLOGICAL SIGNIFICANCE OF AN ALLUVIAL GEOARCHIVE: COMPARATIVE OSL AND AMS 14C DATING FROM GREECE*

The Basin of Phlious in southern Greece is known for its thick colluvial and alluvial deposits from the Holocene. It offers a good opportunity to reconstruct the history of Holocene soil erosion and its interaction with historical farming activities. In this study, we present new results based on optically stimulated luminescence (OSL) dating from the Basin of Phlious. The comparison between OSL and ¹⁴C AMS ages shows good agreement, and demonstrates the need for the detection of insufficiently bleached OSL samples in order to obtain accurate results. The discovery of a Neolithic site, buried under thick alluvial deposits, confirms the hitherto postulated Neolithic human impact on the landscape.     

考古学所见长江三峡夏商周时期的渔业生产

本通过对考古发现的长江三峡渔具和鱼类遗骸的统计分析,将该区域内夏商周时期的渔业生产分为东、西两大区域,并对两区的鱼具及鱼类进行归纳、分析和比较,指出研究先秦渔业,对认识三峡古代化、中国渔业史和鱼类生态,具有重要的意义。     

智慧景区IT能力模型及其核心构成研究

物联网、云计算等最新信息技术的发展推动了智慧景区的建设.本文首先讨论了智慧景区的建设内涵是,景区具备了迅速、灵活、正确地理解和解决游客服务问题的能力;其次,运用企业IT能力理论,构建了智慧景区的IT能力体系框架;最后,提出智慧景区的建设重点是游客感知系统、决策支持系统和游客服务系统三个核心系统.     

IN VITRO DECOMPOSITION OF BONE COLLAGEN BY SOIL BACTERIA: THE IMPLICATIONS FOR STABLE ISOTOPE ANALYSIS IN ARCHAEOMETRY*

To understand biogenic collagen type I decomposition and to establish how diagenesis may bias archaeometric data, modern mammalian bone was inoculated with a selection of ubiquitous soil bacteria. The presence of exogenous microbial biomass in the inoculated specimens was then checked microscopically prior to collagen extraction. The experimentally degraded bone collagen showed altered amino acid compositions, attributable to the selective breakdown of certain amino acids by the bacteria. While both the bulk collagen extract and the single amino acids exhibited shifts to more negative δ¹³ C-values, enrichment was recorded for general δ¹³ N, and a depletion trend relative to unaltered collagen was observed for individual amino acid δ¹³ N. One explanation for the enrichment of the global δ¹⁵N-values is cleavage of peptide bonds, which leaves ¹⁵ N within the substrate, while the change of ¹³C is mostly due to the altered amino acid composition. On the other hand, possible repolymerization of cleavage products under experimental conditions may also be responsible for the depletion trend of individual amino acid δ¹³C- and δ¹⁵ N-values. This paper discusses the results as a basis for the development of a method for the reconstruction of the isotopic abundance of the original collagen, using the amino acid composition of the degraded product, the contribution of individual amino acids to its global δ-values and of isotope discriminations implied in the microbial decomposition.     

BULK STABLE LIGHT ISOTOPIC RATIOS IN RECENT AND ARCHAEOLOGICAL RESINS: TOWARDS DETECTING THE TRANSPORT OF RESINS IN ANTIQUITY?*

We have applied and refined methods for the determination of bulk hydrogen, carbon and oxygen isotope ratios in modern and archaeological resins. The modern resins have a wide range of isotopic values and vary within the same tree, between individual trees, with species and location. For all isotopes measured, there is a general trend of increasing depletion of the heavier isotope with increasing altitude. There is also a linear trend between depletion of δD and δ¹³C values with increasing latitude; this trend is less clear for oxygen, but is related to the meteoric water line. Two case studies using archaeological resins known or suspected to have been transported in antiquity have been investigated to determine whether isotopic signatures can assist in pinpointing the geographical origin of the resin: Pistacia sp. resin from Canaanite amphorae imported into Egypt from known geographical locations in the eastern Mediterranean during the Late Bronze Age, and Roman amphorae sherds lined with Pinus sp. resin from sites ranging from Britain to the eastern Mediterranean. These results show separate groupings between the two resin types (pine/pistacia) and between the modern/archaeological resins. Some archaeological samples are distinct from the others and the modern resins show differences between geographical areas. However, there are no clear patterns relating the different Canaanite fabrics or the suggested manufacturing site of the Roman amphorae.     

Correlation BetweenC Ages and Aspartic Acid Racemization at the Upper Palaeolithic Site of the Abri Pataud (Dordogne, France)

The Upper Palaeolithic site of the Abri Pataud (Dordogne, France) has been the subject of numerous¹⁴C age determinations which cover the period from 20,400±450 years (OXA-373) to 34,250±675 years (Grn-4507). The racemization ratios of aspartic acid have been determined in 26 fossil bones. The bones are present in two different sedimentary surroundings: levels (fine deposits with numerous artefacts and fossil bones) and “éboulis” (coarse deposits derived from the neighbouring limestone cliff). Racemization ratios for total aspartic acid have a poor correlation with¹⁴C ages (respectivelyr²=0·59 and 0·82 for the two environments) but apparent racemization rates are clearly dependent on the type of deposits (levels: K=4·4×10⁻⁶year⁻¹; éboulis: K=9×10⁻⁶year⁻¹).Racemization ratios of aspartic acid in a high molecular weight protein fraction (>10,000 Da) correlate much better with¹⁴C ages (r²=0·999) for the samples from the levels (k=2·1×10⁻⁵year⁻¹). From this regression line we estimate ages for two Aurignacian levels: level 6≈29,560 years and level 9≈30,440 years .It is noteworthy that none of the regression lines intercepts the origin. Racemization of aspartic acid appears to occur only after a delay of many thousands of years. This phenomenon could be the result of a coupling between the degradation of proteins and the racemization of amino acids.