352 research outputs found

    Palliative care, double effect and the law in Australia

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    Care and decision-making at the end of life that promotes comfort and dignity is widely endorsed by public policy and the law. In ethical analysis of palliative care interventions that are argued potentially to hasten death, these may be deemed to be ethically permissible by the application of the doctrine of double effect, if the doctor’s intention is to relieve pain and not cause death. In part because of the significance of ethics in the development of law in the medical sphere, this doctrine is also likely to be recognized as part of Australia’s common law, although hitherto there have been no cases concerning palliative care brought before a court in Australia to test this. Three Australian States have, nonetheless, created legislative defences that are different from the common law with the intent of clarifying the law, promoting palliative care, and distinguishing it from euthanasia. However, these defences have the potential to provide less protection for doctors administering palliative care. In addition to requiring a doctor to have an appropriate intent, the defences insist on adherence to particular medical practice standards and perhaps require patient consent. Doctors providing end-of-life care in these States need to be aware of these legislative changes. Acting in accordance with the common law doctrine of double effect may not provide legal protection. Similar changes are likely to occur in other States and Territories as there is a trend towards enacting legislative defences that deal with the provision of palliative care

    Antigenic evolution of SARS-CoV-2 in immunocompromised hosts

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    Tolerance-conferring defensive symbionts and the evolution of parasite virulence

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    Duality based error control for the Signorini problem

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    In this paper we study the a posteriori bounds for a conforming piecewise linear finite element approximation of the Signorini problem. We prove new rigorous a posteriori estimates of residual type in LpL^{p}, for p∈(4,∞)p \in (4,\infty) in two spatial dimensions. This new analysis treats the positive and negative parts of the discretisation error separately, requiring a novel sign- and bound-preserving interpolant, which is shown to have optimal approximation properties. The estimates rely on the sharp dual stability results on the problem in W2,(4−ε)/3W^{2,(4 - \varepsilon)/3} for any ε≪1\varepsilon \ll 1. We summarise extensive numerical experiments aimed at testing the robustness of the estimator to validate the theory

    Social information use shapes the coevolution of sociality and virulence

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    Population mixing promotes arms race host-parasite coevolution.

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    Open access article. Please cite the published version available on the Royal Society web site by following the DOI above.The consequences of host-parasite coevolution are highly contingent on the qualitative coevolutionary dynamics: whether selection fluctuates (fluctuating selection dynamic; FSD), or is directional towards increasing infectivity/resistance (arms race dynamic; ARD). Both genetics and ecology can play an important role in determining whether coevolution follows FSD or ARD, but the ecological conditions under which FSD shifts to ARD, and vice versa, are not well understood. The degree of population mixing is thought to increase host exposure to parasites, hence selecting for greater resistance and infectivity ranges, and we hypothesize this promotes ARD. We tested this by coevolving bacteria and viruses in soil microcosms and found that population mixing shifted bacteria-virus coevolution from FSD to ARD. A simple theoretical model produced qualitatively similar results, showing that mechanisms that increase host exposure to parasites tend to push dynamics towards ARD. The shift from FSD to ARD with increased population mixing may help to explain variation in coevolutionary dynamics between different host-parasite systems, and more specifically the observed discrepancies between laboratory and field bacteria-virus coevolutionary studies.Natural Environment Research Council (NERC)Marie Curie Intra-European Fellowship (FP7)The Royal Societ

    Trade-offs and the Evolution of Age-Specific Resistance to Infectious Disease

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    Innate, infection-preventing resistance often varies between host life stages. Juveniles are more resistant than adults in some species, whereas the opposite pattern is true in others. This variation cannot always be explained by prior exposure or physiological constraints and so it has been hypothesized that trade-offs with other life-history traits may be involved. However, little is known about how trade-offs between various life-history traits and resistance at different life stages affect the evolution of age-specific resistance. Here, we use a mathematical model to explore how trade-offs with natural mortality, reproduction and maturation combine to affect the evolution of resistance at different life stages. Our results show that certain combinations of trade-offs have substantial effects on whether adults or juveniles are more resistant, with trade-offs between juvenile resistance and adult reproduction inherently more costly than trade-offs involving maturation or mortality (all else being equal), resulting in consistent evolution of lower resistance at the juvenile stage even when infection causes a lifelong fecundity reduction. Our model demonstrates how the differences between patterns of age-structured resistance seen in nature may be explained by variation in the trade-offs involved and our results suggest conditions under which trade-offs tend to select for lower resistance in juveniles than adults

    Transposition: A CRISPR Way to Get Around

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    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordCRISPR-Cas systems provide sequence-specific immunity against selfish genetic elements in prokaryotes. Now, two studies show that transposon-encoded variants can guide sequence-specific transposition. These findings have important practical implications but also raise questions of why and how this strategy would benefit transposons
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