Taxonomic, anatomical, and spatio-temporal variations in the stable carbon and nitrogen isotopic compositions of plants from an African savanna

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios are commonly used to reconstruct palaeodiets and palaeoenvironments. The method is based on our knowledge of isotopic patterns in plants, which are subject to taxonomic and environmental variability. While previous researchers have addressed isotopic variability amongst plants, no studies have looked extensively at a broad suite of taxa over multiple temporal scales from within the savanna biome so as to provide baseline data for palaeodietary and palaeoenvironmental studies. Here we document variations in the isotopic compositions of plants collected over two years from the Kruger National Park, South Africa, with respect to species and anatomical differences, and the influences of geological substrate and spatio-temporal shifts in climate. Results show that environmentally-induced carbon isotopic variations in plants within this region are generally smaller than 2‰, which is lower than what has been previously reported for plants compared across multiple habitat-types. These data suggest that δ¹³C differences of 2‰ or more (or 1‰ if the diet is predominantly C₄) between animals from a given area reliably indicate real dietary differences. Plant δ¹⁵N values vary greatly between different microhabitats (by up to 4‰), responding to a range of environmental influences that may, in turn, significantly influence variation in animal δ¹⁵N values.     

Blood transfusion between the wars

This article examines the introduction of blood transfusion into general practice from the end of the First World War to the Second World War. Developments during most of this period were not the result of new discoveries but rather the spread of ideas and the establishment of donor organizations to secure an adequate blood supply. The identification, testing, and organization of potential donors were done in a wide variety of settings that reflected differences in political and cultural experiences. At the end of the 1930s, with war approaching, the resolution of problems with storage of blood and the discovery of new techniques for separating and storing plasma dramatically changed transfusion practice. Thus, the innovations of the Second World War were very much based on the development of broad donor organizations plus the new technical discoveries that had occurred during the interwar period.     

Geochemistry of sauceboats excavated from Independence National Historical Park (Philadelphia): evidence for a Bonnin and Morris (c. 1770–73) provenance and implications for the development of nascent American porcelain wares

Porcelain sauceboats excavated from a privy with a late 18th century (1786 or later) context at Independence National Historical Park (INHP) are anomalously Al-rich compared with previously analysed Anglo-American sulphurous phosphatic wares. Apart from their S content, they are most similar to phosphatic W^m Reid porcelain (Brownlow Hill, Liverpool, c. 1755–67, and its branch at Shelton, Staffordshire) in terms of their major element constituents, but they contain heavy minerals (e.g., TiO₂ polymorphs) and in this regard resemble a dated (1773) silicious-aluminous-calcic (S-A-C) Bonnin and Morris porcelain (Philadelphia) openwork porcelain basket. In terms of morphology and composition, some TiO₂ polymorphs in the 1773 basket match those from clay from White Clay Creek, Delaware, a resource reputedly exploited by Bonnin and Morris. Their high Nb/Cr ratios indicate derivation from a metapelitic (or granitic pegmatite) source. So too do some from the INHP sauceboats, although others are chrome-rich (∼1% Cr₂O₃), indicating a mafic source. The bedrock beneath White Clay Creek includes metasediments, granitic pegmatite, and metabasites (e.g., of the Wissahickon Formation), pointing to a local source for the TiO₂ polymorphs in the porcelains described here. Although the evidence for a Bonnin and Morris provenance for the INHP sauceboats is circumstantial, their enrichment in heavy minerals, unusual – perhaps experimental – compositions, and aesthetic characteristics nonetheless suggest a Philadelphia origin for these artifacts. The compositions of 18th century Philadelphia porcelain support the contention that knowledge of phosphatic and S-A-C pastes originating in London was transferred first to Staffordshire and Liverpool, and then to Philadelphia, perhaps via a potter by the name of W^m Ball.     

Ancient bronze technology and nomadic communities of the Middle Gobi Desert,Mongolia

The Xiongnu period of Mongolian prehistory (ca. 3rd century BC–AD 2nd century) is notable for the emergence of an expansive nomadic state and major changes in metallurgical and ceramic technologies. A number of Xiongnu period and pre-Xiongnu period bronze and bronze-related artifacts from the site at Baga Gazaryn Chuluu in the Middle Gobi province of Mongolia were examined for their chemical compositions and microstructures. They include finished objects, leftovers from casting, and pieces of slag from copper smelting and the assemblage likely represents a combination of local and regional production as well as long-distance exchange items. Results show that the entire bronze manufacturing process, from smelting to fabrication, is represented at BGC sites and bronze working may have been technologically self-sufficient, though ore sources are still uncertain. Our evidence suggests that this bronze assemblage was the result of two different technological traditions characterized by either the dominant use of arsenic, enforced apparently by restriction in tin supply, or the profuse use of both tin and lead. The arsenic-based tradition was observed in the majority of pre-Xiongnu period objects while the tin and lead recipes were verified in most objects dating to the Xiongnu period. This shift in bronze tradition may reflect changes in inter-regional interaction with frontier groups beyond the Gobi Desert and with the early state societies of China.