664 research outputs found

    Hunter-Gatherer Societies Innovate and Adapt; They Do Not Accumulate Complexity Comment

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    Higher-order compatible finite element schemes for the nonlinear rotating shallow water equations on the sphere

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    We describe a compatible finite element discretisation for the shallow water equations on the rotating sphere, concentrating on integrating consistent upwind stabilisation into the framework. Although the prognostic variables are velocity and layer depth, the discretisation has a diagnostic potential vorticity that satisfies a stable upwinded advection equation through a Taylor-Galerkin scheme; this provides a mechanism for dissipating enstrophy at the gridscale whilst retaining optimal order consistency. We also use upwind discontinuous Galerkin schemes for the transport of layer depth. These transport schemes are incorporated into a semi-implicit formulation that is facilitated by a hybridisation method for solving the resulting mixed Helmholtz equation. We illustrate our discretisation with some standard rotating sphere test problems.Comment: accepted versio

    Prospective associations between cardiovascular reactions to acute psychological stress and change in physical disability in a large community sample

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    Exaggerated haemodynamic reactions to acute psychological stress have been implicated in cardiovascular disease outcomes, while lower reactions have been considered benign. This study examined, in a large cohort, the prospective associations between stress reactivity and physical disability. Blood pressure and pulse rate were measured at rest and in response to a stress task. Physical disability was assessed using the OPCS survey of disability at baseline and five years later. Heart rate reactivity was negatively associated with change in physical disability over time, such that those with lower heart rate reactivity were more likely to deteriorate over the following five years. These effects remained significant following adjustment for a number of confounding variables. These data give further support to the recent argument that for some health outcomes, lower or blunted cardiovascular stress reactivity is not necessarily protective

    A compatible finite element discretisation for the nonhydrostatic vertical slice equations

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    We present a compatible finite element discretisation for the vertical slice compressible Euler equations, at next-to-lowest order (i.e., the pressure space is bilinear discontinuous functions). The equations are numerically integrated in time using a fully implicit timestepping scheme which is solved using monolithic GMRES preconditioned by a linesmoother. The linesmoother only involves local operations and is thus suitable for domain decomposition in parallel. It allows for arbitrarily large timesteps but with iteration counts scaling linearly with Courant number in the limit of large Courant number. This solver approach is implemented using Firedrake, and the additive Schwarz preconditioner framework of PETSc. We demonstrate the robustness of the scheme using a standard set of testcases that may be compared with other approaches.Comment: Response to reviewers. Thanks to Golo Wimmer for pointing out the wrong factor of h in the interior penalty for diffusion - this was also wrong in the codes and we reran the dense bubble testcase

    Inoculation and pelleting of lupin and serradella seed

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    LUPINS AND SERRADELLA are not as extensively grown in Western Australia as some other legumes, but they are useful pasture species, particularly on poorer sandy soils. Virgin soils may contain rhizobial bacteria capable of nodulating some members of the lupin group, but none of these bacteria have been found to nodulate serradella (Lange, 1961). The use of inoculated seed is imperative except where lupins have been grown before

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    Homo neanderthalensis and the evolutionary origins of ritual in Homo sapiens

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    There is a large, if disparate, body of archaeological literature discussing specific instantiations of symbolic material culture and the possibility of ritual practices in Neanderthal populations. Despite this attention, however, no single synthesis exists that draws upon cognitive, psychological and cultural evolutionary theories of ritual. Here, we review the evidence for ritual-practice among now-extinct Homo neanderthalensis, as well as the necessary cognitive pre-conditions for such behaviour, in order to explore the evolution of ritual in Homo sapiens. We suggest that the currently available archaeological evidence indicates that Neanderthals may have used ‘ritualization’ to increase the successful transmission of technical knowledge across generations—providing an explanation for the technological stability of the Middle Palaeolithic and attesting to a survival strategy differing from near-contemporary H. sapiens. / This article is part of the theme issue ‘Ritual renaissance: new insights into the most human of behaviours’

    Terminal Pleistocene emergence of maritime interaction networks across Wallacea

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    The crossing of the Wallacean islands and settlement of Sahul by modern humans over 50,000 years ago, represents the earliest successful seafaring of our species anywhere in the world. Archaeological research throughout this vast island archipelago has recovered evidence for varied patterns in island occupation, with accumulating evidence suggesting a significant change in cultural activities and interaction amongst island communities following the LGM. New forms of technology such as shell fish hooks and adzes appear alongside standardised forms of shell beads, indicating that these technological innovations were accompanied by shared styles of personal ornamentation. Simultaniously, obsidian from a single, off-island source is found in the archaeological assemblages on at least four islands. We explore these implied spheres of interaction across Wallacea, with a focus on the terminal-Pleistocene/early-Holocene cultural materials and customs linking the southeastern Wallacean islands of Alor, Timor, and Kisar, and other parts of greater Wallacea and Near Oceania
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