Time and energy constraints and the relationships between currencies in foraging theory

Measured foraging strategies often cluster around values that maximize the ratio of energy gained over energy spent while foraging (efficiency), rather than values that would maximize the long-term net rate of energy gain (rate). The reasons for this are not understood. This paper focuses on time and energy constraints while foraging to illustrate the relationship between efficiency and rate-maximizing strategies and develops models that provide a simple framework to analyze foraging strategies in two distinct foraging contexts. We assume that while capturing and ingesting food for their own use (which we term feeding), foragers behave so as to maximize the total net daily energetic gain. When gathering food for others or for storage (which we term provisioning), we assume that foragers behave so as to maximize the total daily delivery, subject to meeting their own energetic requirements. In feeding contexts, the behavior maximizing total net daily gain also maximizes efficiency when daily intake is limited by the assimilation capacity. In contrast, when time available to forage sets the limit to gross intake, the behavior maximizing total net daily gain also maximizes rate. In provisioning contexts, when daily delivery is constrained by the energy needed to power self-feeding, maximizing efficiency ensures the highest total daily delivery. When time needed to recoup energetic expenditure limits total delivery, a low self-feeding rate relative to the rate of energy expenditure favors efficient strategies. However, as the rate of self-feeding increases, foraging behavior deviates from efficiency maximization in the direction predicted by rate maximization. Experimental manipulations of the rate of self-feeding in provisioning contexts could be a powerful tool to explore the relationship between rate and efficiency-maximizing behavio

Long-distance landscapes: from quarries to monument at Stonehenge.

Stonehenge is famous for the distances moved by its stones, both sarsens and bluestones. In particular, the bluestones have their geological origins in West Wales, 225km away. Recent excavations at two of these bluestone sources – one for rhyolite and one for spotted dolerite – have identified evidence of megalith quarrying around 3000 BC, when Stonehenge’s first stage was constructed. This remarkable movement of bluestones from Wales coincided with a decline in regional cultural distinctions between west and east, suggesting that building Stonehenge may have served to unify the Neolithic populations of Britain

Commentary - Better lung health for all: A British Thoracic Society and Pan African Thoracic Society initiative

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Megalith quarries for Stonehenge’s bluestones. Review

Geologists and archaeologists have long known that the bluestones of Stonehenge came from the Preseli Hills of west Wales, 230km away, but only recently have some of their exact geological sources been identified. Two of these quarries - Carn Goedog and Craig Rhos-y-felin - have now been excavated to reveal evidence of megalith quarrying around 3000 BC - the same period as the first stage of the construction of Stonehenge. The authors present evidence for the extraction of the stone pillars and consider how they were transported, including the possibility that they were erected in a temporary monument close to the quarries, before completing their journey to Stonehenge

Provisional Survey of Aitutaki, Cook islands Sites and Monuments May-June 2017

The archaeological survey work detailed in this report was undertaken by Colin Richards and Jane Downes (University of the Highlands and Islands, UK), Kate Welham (Bournemouth University, UK), Francisco Torres Hochstetter (MAPSE, Rapa Nui (Easter Island), Chile) and Lawrence Shaw (New Forest National Park Authority, UK), working with Ngaakitai Pureariki (Punarei Aitutaki), with the permission of the Aitutaki Council, and Cook Islands Research Permit (Ref. 15-16a), working between 23rd May and 2nd June 2017. The archaeological work comprised site survey and location using GPS, geophysical survey, and surface collection of artefacts. A database of the sites has been produced as a Cultural Heritage Record, and lodged with the Aitutaki Islands Council. All artefacts have been left on the island with the Aitutaki Islands Council

The age of Stonehenge

Stonehenge is the icon of British prehistory, and continues to inspire ingenious investigations and interpretations. A current campaign of research, being waged by probably the strongest archaeological team ever assembled, is focused not just on the monument, but on its landscape, its hinterland and the monuments within it. The campaign is still in progress, but the story so far is well worth reporting. Revisiting records of 100 years ago the authors demonstrate that the ambiguous dating of the trilithons, the grand centrepiece of Stonehenge, was based on samples taken from the wrong context, and can now be settled at 2600-2400 cal BC. This means that the trilithons are contemporary with Durrington Walls, near neighbour and Britain's largest henge monument. These two monuments, different but complementary, now predate the earliest Beaker burials in Britain – including the famous Amesbury Archer and Boscombe Bowmen, but may already have been receiving Beaker pottery. All this contributes to a new vision of massive monumental development in a period of high European intellectual mobility…