Sex ratios and life tables: Historical demography of the age at which women outnumber men in seven countries, 1850–2016

Abstract

The male/female sex ratio (SR) and its age-specific patterns vary considerably across time and place. The SR generally begins male-biased at birth and becomes female-biased later in life, but this relationship should respond to historical trends and events. Temporal trends in SRs remain largely unstudied and formal demographic relationships are not well defined. We (1) define SRs in a life table framework, (2) estimate the age at which the number of males and females achieves parity—the sex ratio crossover (SRX)—using basic life table methods, and (3) explore historical and international patterns in these trends. Using publicly-available data from the Human Mortality Database, we construct SR and SRX measures from period and cohort life tables. Analyses explore temporal patterns for seven countries in different global regions since 1850. Overall temporal trends show the SRX advancing to older ages. The SRX also appears to respond to historical events such as wars and epidemics. The measure is simple to construct from life table data, and provides additional insight into the historical context of gender dynamics.     

A very public affair: art meets science

ABSTRACT

What happens in interdisciplinary practices between the arts and sciences? What determines their successes and failures, and how they should be conducted? Here I propose that we can deepen our understanding of them by looking at the role of one specific and, to my mind, vital aspect of many (most?) successful art/science collaborations, namely their presence in public. More specifically, I suggest that museums, having played a crucial historical role in shaping some specialized disciplinary thought, are now well-placed to encourage an opposite tendency towards trans-disciplinary activity. I elaborate this argument by focusing on three characteristics of museums that have made them ideal places to locate art-science collaborations: the role of exhibitions as units of investigation; the ascendency of artist/curators as unusual enquirers; and the enduring value of middle-sized things in these risky initiatives.     

Climate deterioration and land-use change in the first millennium BC: perspectives from the British palynological record

Climate deterioration at around the time of the Bronze Age/Iron Age transition has for long been argued to have resulted in upland abandonment in northern and western Britain, and recent research has provided evidence that a major climate downturn from 850 cal BC caused settlement abandonment in western Europe and potentially worldwide. It is, however, unclear to what extent only ‘marginal’ sites were affected, due to the lack of any systematic attempt to view the evidence for settlement and land-use change across a range of landscape types with differing sensitivities to environmental change. This paper addresses this issue by an evaluation of 75 pollen sequences spanning the late Bronze Age and early Iron Age in Britain to assess whether climatic deterioration was sufficient to cause widespread land abandonment. The results provide no evidence for wholesale land-use change at this time; the overall picture is one of continuity of land use or even increased agricultural activity. There are, however, hints of regional variability, with a greater tendency to abandonment of upland areas in Wales, and signs of woodland regeneration in agriculturally productive areas of lowland central southern England. The latter pattern may reflect a combination of rising ground-water levels affecting local land-use in the immediate vicinity of the mires which provide the source of the pollen data, against a backdrop of regional-scale social and economic changes at the Bronze Age-Iron Age transition.     

High-resolution radiocarbon dating of marine materials in archaeological contexts: radiocarbon marine reservoir variability between Anadara, Gafrarium, Batissa, Polymesoda spp. and Echinoidea at Caution Bay, Southern Coastal Papua New Guinea

The remains of shellfish dominate many coastal archaeological sites in the Pacific and provide a wealth of information about economy, culture, environment and climate. Shells are therefore the logical sample type to develop local and regional radiocarbon chronologies. The calibration of radiocarbon (¹⁴C) dates on marine animals is not straightforward, however, requiring an understanding of habitat and dietary preferences as well as detailed knowledge of local ocean conditions. The most complex situations occur where terrestrial influences impinge on the marine environment resulting in both the enrichment and depletion of ¹⁴C (Ulm Geoarchaeology 17(4):319–348, 2002; Petchey and Clark Quat Geochronol 6:539–549, 2011). A sampling protocol that combines a high-resolution excavation methodology, selection of short-lived samples identified to species level, and a tri-isotope approach using ¹⁴C, δ¹³C and δ¹⁸O, has given us the ability to identify ¹⁴C source variation that would otherwise have been obscured. Here, we present new research that details high-resolution mapping of marine ¹⁴C reservoir variation between Gafrarium tumidum, Gafrarium pectinatum, Anadara granosa, Anadara antiquata, Batissa violacea, Polymesoda erosa and Echinoidea from the Bogi 1 archaeological site, Caution Bay, southern coastal Papua New Guinea. These isotopes highlight specific dietary, habitat and behavioural variations that are key to obtaining chronological information from shell radiocarbon determinations.