116 research outputs found

    The 600 yr eruptive history of Villarrica Volcano (Chile) revealed by annually laminated lake sediments

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    Lake sediments contain valuable information about past volcanic and seismic events that have affected the lake catchment, and they provide unique records of the recurrence interval and magnitude of such events. This study uses a multilake and multiproxy analytical approach to obtain reliable and high-resolution records of past natural catastrophes from similar to 600-yr-old annually laminated (varved) lake sediment sequences extracted from two lakes, Villarrica and Calafquen, in the volcanically and seismically active Chilean Lake District. Using a combination of micro-X-ray fluorescence (mu XRF) scanning, microfacies analysis, grain-size analysis, color analysis, and magnetic-susceptibility measurements, we detect and characterize four different types of event deposits (lacustrine turbidites, tephra-fall layers, runoff cryptotephras, and lahar deposits) and produce a revised eruption record for Villarrica Volcano, which is unprecedented in its continuity and temporal resolution. Glass geochemistry and mineralogy also reveal deposits of eruptions from the more remote Carran-Los Venados volcanic complex, Quetrupillan Volcano, and the Huanquihue Group in the studied lake sediments. Time-series analysis shows 112 eruptions with a volcanic explosivity index (VEI) >= 2 from Villarrica Volcano in the last similar to 600 yr, of which at least 22 also produced lahars. This significantly expands our knowledge of the eruptive frequency of the volcano in this time window, compared to the previously known eruptive history from historical records. The last VEI >= 2 eruption of Villarrica Volcano occurred in 1991. Based on the last similar to 500 yr, for which we have a complete record from both lakes, we estimate the probability of the occurrence of future eruptions from Villarrica Volcano and statistically demonstrate that the probability of a 22 yr repose period (anno 2013) without VEI >= 2 eruptions is <= 1.7%. This new perspective on the recurrence interval of eruptions and historical lahar activity will help improve volcanic hazard assessments for this rapidly expanding tourist region, and it highlights how lake records can be used to significantly improve historical eruption records in areas that were previously uninhabited

    False friends in the Fanfanyu

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    In the present article, a remarkable phenomenon is brought to the attention of those interested in early Chinese translations of Buddhist texts: false friends in the Fanfanyu (T54n2130). Baochang's Sanskrit-Chinese lexicon that was compiled as early as 517 AD reveals some curious examples of faux amis. In the present contribution, this case will be illustrated with references from the Shanjian lü piposha (T24n1462), a fifth century Chinese translation of the Samantapāsādikā, Buddhaghosa's commentary on the Pāli Vinaya. The fact that Baochang did not realise that this text was not translated from Sanskrit, inadvertently gave rise to some interesting jeux de mots

    3D modelling of the flow of self-compacting concrete with or without steel fibres. Part I: slump flow test

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    In part I of this two-part paper, a three-dimensional Lagrangian smooth particle hydrodynamics method has been used to model the flow of self-compacting concrete (SCC) with or without short steel fibres in the slump cone test. The constitutive behaviour of this non-Newtonian viscous fluid is described by a Bingham-type model. The 3D simulation of SCC without fibres is focused on the distribution of large aggregates (larger than or equal to 8 mm) during the flow. The simulation of self-compacting high- and ultra-high- performance concrete containing short steel fibres is focused on the distribution of fibres and their orientation during the flow. The simulation results show that the fibres and/or heavier aggregates do not precipitate but remain homogeneously distributed in the mix throughout the flow

    What makes a bully a cyberbully? Unravelling the characteristics of cyberbullies across twenty-five European countries

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    The characteristics of bullies who act face-to-face and those who do so in cyberspace were compared directly in one sample across twenty-five countries. The role of cross-country differences in technological infrastructure was also explored. Cyberbullies compared to face-to-face bullies were more likely to engage in risky online activities, spend more time online, and found it easier to be themselves online. Private access to the internet did not make a difference. Gender differences showed girls more likely to be cyber- than face-to-face bullies if they have a profile on a social networking site. Age and internet ability beliefs were also positively but not independently associated with cyberbullying. Cross-country differences were small and patterns remained mostly stable across countries, suggesting that individual and not country-level characteristics are pivotal in explaining cyberbullying

    Prediction model for evaluation of reconfigurable interconnects in distributed shared-memory systems

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    Reconfigurable interconnection networks for distributed shared memory machines exploit properties of the workload dynamics that are not easily captured by statistical traffic models. Therefore, when designing such a network, one should make trade-offs based on full-system simulation for all viable workloads. It is however very time-consuming to do such simulations. In this paper, we present a technique that can predict the performance of a machine for different network parameters, based on the results of only one full simulation run. We also define confidence intervals for our prediction, and analyze the impact of several assumptions that were made
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