Volcanic activity has frequently been linked to Quaternary environmental change, either by driving climate modification 1,2 or in response to environmental changes 3 . Although a link has been established between large explosive eruptions and small (0.5 ЊC), brief (1-2 years) falls in global temperatures 4 , both the evidence and mechanisms responsible for longer episodes of eruptioninduced planetary cooling remain questionable 1,2,5,6 . In contrast, recent research based on ice-core data suggests that rapid climate changes during the past 110,000 years increased explosive volcanic activity 7 . Here we present a statistical analysis relating the frequency of explosive activity of Mediterranean volcanoes-based on dated 8-11 tephra layers in deep-sea sediment cores-to the rate of late Quaternary sea-level change. The nonlinear correlation between the two is tentatively explained in terms of dynamic responses of the volcanoes to stress-related influences on various spatial scales. The correlation supports a mechanism or mechanisms by which the climate-driven growth and decay of large ice sheets can influence the eruptive chronologies of distant volcanic edifices via changes in global sea level.The possibility that late Quaternary environmental changes influenced the frequency and magnitude of volcanic eruptions has only recently been considered. New research based on the GISP2 ice core 7 has produced a continuous record of explosive volcanism in the Northern Hemisphere over the past 110 kyr. The record identifies distinct periods of enhanced volcanic activity (notably at 35-22 and 17-6 kyr ago) which coincide with periods of rapid environmental change. In areas where active volcanism 3 and Quaternary glaciation coincide, the correlation between the events can be explained by the effect of changing ice volumes on crustal stresses 12 . In contrast, the effect of ice-sheet volume changes on unglaciated volcanic areas remains problematical. Several authors 6,13-15 have proposed that meltwater loading and unloading could influence volcanic activity at sites distant from areas of ice accumulation through the global redistribution of water, although this hypothesis has never been tested. Here we examine the evidence for a link between such a redistribution and explosive volcanic activity, by comparing the temporal distribution of tephra layers in Mediterranean deep-sea cores 8-11 with established global sea-level curves for the late Quaternary period. All the active volcanic centres in this region ( Fig. 1) either form islands or are adjacent to coastlines, excepting Monte Vulture (Italy) which lies ϳ50 km from the sea.The validity of both the correlation, and the proposed model, is crucially dependent on first, the accuracy with which ages are attributed to individual tephra layers, and second, on limited reworking and resedimentation of the tephra. The available data consist of 81 data layers (both megascopic and determined from a high percentage of volcanic glass in the sediment) in deep-sea cores from the Tyrrhenian 10...

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The material properties of ligaments are not well characterized at rates of deformation that occur during high-speed injuries. The aim of this study was to measure the material properties of lateral collateral ligament of the porcine stifle joint in a uniaxial tension model through strain rates in the range from 0.01 to 100/s. Failure strain, tensile modulus and failure stress were calculated. Across the range of strain rates, tensile modulus increased from 288 to 905 MPa and failure stress increased from 39.9 to 77.3 MPa. The strain-rate sensitivity of the material properties decreased as deformation rates increased, and reached a limit at approximately 1/s, beyond which there was no further significant change. In addition, time resolved microfocus small angle X-ray scattering was used to measure the effective fibril modulus (stress/fibril strain) and fibril to tissue strain ratio. The nanoscale data suggest that the contribution of the collagen fibrils towards the observed tissue-level deformation of ligaments diminishes as the loading rate increases. These findings help to predict the patterns of limb injuries that occur at different speeds and improve computational models used to assess and develop mitigation technology.

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