Tikal timbers and temples: ancient Maya agroforestry and the end of time

Tikal, a major lowland Maya civic-ceremonial center in the heart of the Petén region of Central America, relied heavily on the adjacent lowland rainforest as a resource base for fuel and construction materials. In this study, we analyzed 135 wood samples from timbers used in the construction of all six of the city's major temples as well as two major palaces to determine which tree species were being exploited and to better understand ancient Maya agroforestry practices during the Late Classic period. We found evidence for a change in preference from the large-growing, upland forest species, Manilkara zapota, to a seasonal wetland species Haematoxylon campechianum in A.D. 741 as well as a decrease in lintel beam widths over time. Though M. zapota later returned as the wood species of choice in A.D. 810, beam widths were found to be significantly smaller. These findings concur with models that hypothesize widespread deforestation during the Late Classic period and indicate a declining forest resource base by the 9th century A.D. Because of the many large timbers available for temple construction in the 8th century, some system of forest conservation is indicated for the ancient Maya prior to the Late Classic period.     

‘Everything is made of atoms’: the reprogramming of space and time in post-war London

From the middle of the Second World War until the early 1950s, architects, planners and designers in Britain made an unprecedented investment in reforming the built environment as a means to ensure a stable and secure post-war society. This essay considers the importance of movement, trajectory and repetition within this reconstruction vision and how the organisation of these things provided a basis for imagining a new form of consensual urban community. The essay begins by exploring how the County of London Plan (Abercrombie and Forshaw, 1943) and the Greater London Plan (Abercrombie, 1945) articulated a set of spatio-temporal logics, based on the prescribed trajectory of the individual embedded within a programme of quotidian repetitions. These logics suggested that urban space could be built to foreclose the possibility of historical conflict. The essay then explores the material design of two post-war exhibitions, Britain Can Make It (1946) and the Festival of Britain's South Bank Exhibition (1951), which offered visitors an experiential taster of what these new urban choreographies would feel like. To end, the essay explores the recurrent figure of the atom within post-war public pedagogy. Within this briefly ubiquitous mechanistic image lay an unacknowledged assurance about how hierarchical structures of movement and repetition sustained the material world, just as these things were being invoked to secure London's position across a range of scales from the local urban neighbourhood to the post-war Commonwealth.     

Essentials in the use of mycolic acid biomarkers for tuberculosis detection: response to “High-throughput mass spectrometric analysis of 1400-year-old mycolic acids as biomarkers for ancient tuberculosis infection” by

High molecular weight long-chain mycolic acids are key structural components of the cell envelope of Mycobacterium tuberculosis and they are established as biomarkers for the identification of both ancient and modern tuberculosis. Mycolic acids from M. tuberculosis have a characteristic profile, reflecting contributions from five major distinct homologous series of mycolate structural types. Diagnosis of tuberculosis in archaeological material, using mycolic acid biomarkers, depends on objective recognition of the key characteristic mycolic acid components. A recent article in this journal claimed that tuberculosis could be confirmed in ancient bones by high throughput mass spectrometric analysis of mycolic acids. Scrutiny of the data presented reveals no convincing evidence for the presence of mycolic acids, characteristic of the M. tuberculosis complex, in the skeletal remains examined. This communication reviews the essential criteria necessary for positive tuberculosis diagnosis, using mycolic acids.