2,165 research outputs found

    Mollusk carbonate thermal behaviour and its implications in understanding prehistoric fire events in shell middens

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    Archaeological shell middens are particularly important for reconstructing prehistoric human subsistence strategies. However, very little is known about shellfish processing, especially when related to the use of fire for dietary and disposal purposes. To shed light on prehistoric food processing techniques, an experimental study was undertaken on modern gastropod shells (Phorcus lineatus). The shells were exposed to high temperatures (200-700 °C) to investigate subsequent mineralogy and macro- and microstructural changes. Afterwards, the three-pronged approach was applied to archaeological shells from Haua Fteah cave, Libya (Phorcus turbinatus) and from shell midden sites in the United Arab Emirates (Anadara uropigimelana and Terebralia palustris) to determine exposure temperatures. Results indicated that shells from the Haua Fteah were exposed to high temperatures (600 - 700 °C) during the Mesolithic period (c. 12.7 - 9 ka), whereas specimens from the Neolithic period (c. 8.5 - 5.4 ka) were mainly exposed to lower temperatures (300 - 500 °C). The thermally-induced changes in A. uropigimelana and T. palustris shells from the South East Arabian archaeological sites were similar to those seen in Phorcus spp. suggesting a broad applicability of the experimental results at an interspecific level. Although heat significantly altered the appearance and mineralogy of the shells, 14CAMS ages obtained on burnt shells fit within the expected age ranges for their associated archaeological contexts, indicating that robust radiocarbon ages may still be obtained from burnt shells. Our study indicates that the combination of microstructural and mineralogical observations can provide important information to infer shellfish processing strategies in prehistoric cultures and their change through time.Funding for this study was kindly provided by the EU within the framework (FP7) of the Marie Curie International Training Network ARAMACC (604802) to SM and by the Alexander von Humboldt Postdoctoral Fellowship (1151310) and McKenzie Postdoctoral Fellowship to AP. The Haua Fteah excavations were undertaken with the permission of the Libyan Department of Antiquities and with funding to GB from the Society for Libyan Studies and from the European Research Council (Advanced Investigator Grant 230421), whose support is also gratefully acknowledge

    Tracking of Salmonella Positive Pigs from Farm to Fork in the Republic of Ireland

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    In this study, individual pigs from selected herds of known Salmonella serological status were tracked through the slaughter and dressing process. From all tracked animals, caecal contents, rectal faeces, carcasses (before washing and chilling and after chilling) and pork primal cuts were examined for the presence of Salmonella. All samples were screened for Salmonella using real time PCR and all suspect positive samples were confirmed using the ISO 6579 method for Salmonella. To determine the relationship between Salmonella isolates from different parts of the chain , all isolates are being characterised by Pulse Field Gel Electrophoresis (PFGE). The results suggest that the slaughter and dressing operations have a significant effect on the incidence of Salmonella and that even if pigs are presented for slaughter with caecal or rectal carriage of Salmonella then good slaughter practices can prevent carcass contamination. All data generated in the study is being fed into a quantitative risk assessment model for Salmonella in pork

    An Euler Solver Based on Locally Adaptive Discrete Velocities

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    A new discrete-velocity model is presented to solve the three-dimensional Euler equations. The velocities in the model are of an adaptive nature---both the origin of the discrete-velocity space and the magnitudes of the discrete-velocities are dependent on the local flow--- and are used in a finite volume context. The numerical implementation of the model follows the near-equilibrium flow method of Nadiga and Pullin [1] and results in a scheme which is second order in space (in the smooth regions and between first and second order at discontinuities) and second order in time. (The three-dimensional code is included.) For one choice of the scaling between the magnitude of the discrete-velocities and the local internal energy of the flow, the method reduces to a flux-splitting scheme based on characteristics. As a preliminary exercise, the result of the Sod shock-tube simulation is compared to the exact solution.Comment: 17 pages including 2 figures and CMFortran code listing. All in one postscript file (adv.ps) compressed and uuencoded (adv.uu). Name mail file `adv.uu'. Edit so that `#!/bin/csh -f' is the first line of adv.uu On a unix machine say `csh adv.uu'. On a non-unix machine: uudecode adv.uu; uncompress adv.tar.Z; tar -xvf adv.ta

    Nurses\u27 Alumnae Association Bulletin, April 1962

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    Staff Nurses Association Alumnae Meetings 1961 Social Committee Clara Melville Scholarship Fund Ways and Means Report Cook Book Report Bulletin Committee Private Duty Nurse\u27s Section Hospital Report and Nursing Service Federal Nursing Service Practice of Nursing Report of Student Council Activities Medical Work in Ghan

    The conservation of human functional variants and their effects across mammals

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    Despite the clear potential of livestock models of human functional variants to provide important insights into the biological mechanisms driving human diseases and traits, their use to date has been limited. Generating such models via genome editing is costly and time consuming, and it is unclear which variants will have conserved effects across species. In this study we address these issues by studying naturally occurring livestock models of human functional variants. We show that orthologues of over 1.6 million human variants are already segregating in domesticated mammalian species, including several hundred previously directly linked to human traits and diseases. Models of variants linked to particular phenotypes, including metabolomic disorders and height, are preferentially shared across species, meaning studying the genetic basis of these phenotypes is particularly tractable in livestock. Using machine learning we demonstrate it is possible to identify human variants that are more likely to have an existing livestock orthologue, and, importantly, we show that the effects of functional variants are often conserved in livestock, acting on orthologous genes with the same direction of effect. Consequently, this work demonstrates the substantial potential of naturally occurring livestock carriers of orthologues of human functional variants to disentangle their functional impacts

    Precession of a Freely Rotating Rigid Body. Inelastic Relaxation in the Vicinity of Poles

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    When a solid body is freely rotating at an angular velocity Ω{\bf \Omega}, the ellipsoid of constant angular momentum, in the space Ω1,Ω2,Ω3\Omega_1, \Omega_2, \Omega_3, has poles corresponding to spinning about the minimal-inertia and maximal-inertia axes. The first pole may be considered stable if we neglect the inner dissipation, but becomes unstable if the dissipation is taken into account. This happens because the bodies dissipate energy when they rotate about any axis different from principal. In the case of an oblate symmetrical body, the angular velocity describes a circular cone about the vector of (conserved) angular momentum. In the course of relaxation, the angle of this cone decreases, so that both the angular velocity and the maximal-inertia axis of the body align along the angular momentum. The generic case of an asymmetric body is far more involved. Even the symmetrical prolate body exhibits a sophisticated behaviour, because an infinitesimally small deviation of the body's shape from a rotational symmetry (i.e., a small difference between the largest and second largest moments of inertia) yields libration: the precession trajectory is not a circle but an ellipse. In this article we show that often the most effective internal dissipation takes place at twice the frequency of the body's precession. Applications to precessing asteroids, cosmic-dust alignment, and rotating satellites are discussed.Comment: 47 pages, 1 figur
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