187 research outputs found

    Adaptations and responses of the common dandelion to low atmospheric pressure in high‐altitude environments

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    Atmospheric pressure is an important, yet understudied factor that may shape plant ecology and evolution. By growing plants under controlled conditions at different experimental stations in the Swiss alps, we evaluated the impact of ecologically realistic atmospheric pressures between 660 and 950 hPa on the growth and defence of different dandelion populations. Low atmospheric pressure was associated with reduced root growth and defensive sesquiterpene lactone production. Defence suppression only occurred in populations originating from lower altitudes. Populations from higher altitudes constitutively produced less sesquiterpene lactones and did not suffer from suppression under low atmospheric pressure. Synthesis. We conclude that atmospheric pressure modulates root growth and defence traits, and that evolutionary history shapes plant phenotypic responses to atmospheric pressure. Our findings have important implications for our understanding of altitudinal gradients and the future use of plants as a source of food and bioactive metabolites in extraterrestrial habitats

    Scale-free movement patterns in termites emerge from social interactions and preferential attachments

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    As the number or density of interacting individuals in a social group increases, a transition can develop from uncorrelated and disordered behaviour of the individuals to a collective coherent pattern. We expand this observation by exploring the fine details of termite movement patterns to demonstrate that the value of the scaling exponent ” of a power-law describing the Lévy walk of an individual is modified collectively as the density of animals in the group changes. This effect is absent when termites interact with inert obstacles. We also show that the network of encounters and interactions among specific individuals is selective resembling a preferential attachment mechanism which is important for social networking. TeOur data suggest strongly that preferential attachments, a phenomenon not reported previously, and favourite interactions with a limited number of acquaintances are responsible for the generation of Lévy movement patterns in these social insects

    PrevisĂŁo probabilĂ­stica de enchentes para uma pequena bacia hidrogrĂĄfica do Pantanal.

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    O monitoramento para a previsão de cheias de pequenas bacias hidrogråficas é de grande importùncia tendo em vista a relação dos recursos hídricos com a sociedade, pois pode garantir o uso sustentåvel às comunidades urbanas de cidades lindeiras à bacia. O rio Aquidauana estå inserido na planície Pantaneira sendo considerado vulneråvel à inundaçÔes, no entanto, falta de um sistema eficiente para previsÔes de cheias e inundaçÔes. Assim, este estudo propÔe um sistema de previsão probalística de enchentes para a bacia do Rio Aquidauana. Para tanto foram utilizadas as redes neurais artificiais (RNAs) do tipo MultiLayer Perceptron (treinamento backpropagation) com parùmetros otimizados pelos Algoritmos Genéticos. A RNA foi treinada e avaliada com base em dados de chuva acumulada (mm) e nível de rio (cm) à montante entre os anos de 1995 a 2014. A previsão realizada foi de 1 a 5 dias, tendo como melhor desempenho o modelo para 1 dia de previsão, com resultado de coeficiente de determinação e erro quadråtico médio de 0,93 e 30 (cm), respectivamente

    The ESSnuSB design study: overview and future prospects

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    ESSnuSB is a design study for an experiment to measure the CP violation in the leptonic sector at the second neutrino oscillation maximum using a neutrino beam driven by the uniquely powerful ESS linear accelerator. The reduced impact of systematic errors on sensitivity at the second maximum allows for a very precise measurement of the CP violating parameter. This review describes the fundamental advantages of measurement at the 2nd maximum, the necessary upgrades to the ESS linac in order to produce a neutrino beam, the near and far detector complexes, the expected physics reach of the proposed ESSnuSB experiment, concluding with the near future developments aimed at the project realization.Comment: 19 pages, 11 figures; Corrected minor error in alphabetical ordering of the authors: the author list is now fully alphabetical w.r.t. author surnames as was intended. Corrected an incorrect affiliation for two authors per their reques
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