8 research outputs found

    Future climate impact on spruce bark beetle life cycle in relation to uncertainties in regional climate model data ensembles

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    In this study, we quantify the effect of uncertainties in climate projections on an impact model (IPS) that describes the temperature-dependent swarming and development of Ips typographus. Three forcing climate data sets (ensembles) were used: (1) E-Obs gridded observations, (2) ERA-40 reanalysis data downscaled by eight regional climate models (RCMs) and (3) regional scenarios from one RCM forced by seven GCM simulations representing SRES-A1B, for the period of 1961-2097. The IPS_RCM_ERA40 ensemble members, including IPS_RC3_ERA40, were generally within the IPS_E-Obs confidence limits. The IPS model is however sensitive to the warming during spring and cooling during autumn, and deviations in simulated swarming were related to known climate model biases. The variation between the IPS_RCA3_GCM ensemble members was particularly high in regions where warmer summers (temperature increase from +2 degrees C to +4 degrees C) will induce an additional generation per year, for example a shift from one to two generations per year in south Scandinavia, and an increased frequency of three generations per year in central Europe. Impact assessments based on an ensemble of climate data gives more robust decision support than a single climate model approach because it allows a probabilistic assessment of the geographical areas experiencing a transition in biological response

    Controlling the catalytic bond breaking selectivity of Ni surfaces by step blocking

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    The reactivity of catalytic surfaces is often dominated by very reactive low-coordinated atoms such as step-edge sites1-11. However, very little knowledge exists concerning the influence of step edges on the selectivity in reactions involving multiple reaction pathways. Such detailed information could be very valuable in rational design of new catalysts with improved selectivity. Here we show, from an interplay between scanning tunnelling microscopy experiments and density functional theory calculations, that the activation of ethylene on Ni(111) follows the trend of higher reactivity for decomposition at step edges as compared with the higher-coordinated terrace sites. The step-edge effect is considerably more pronounced for the C-C bond breaking than for the C-H bond breaking, and thus steps play an important role in the bond-breaking selectivity. Furthermore, we demonstrate how the number of reactive step sites can be controlled by blocking the steps with Ag. This approach to nanoscale design of catalysts is exploited in the synthesis of a new high-surface-area AgNi alloy catalyst, which is tested in hydrogenolysis experiments

    Inclusive production of D+,D0,D+s and D∗+ mesons in deep inelastic scattering at HERA

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    Inclusive production cross sections are measured in deep inelastic scattering at HERA for meson states composed of a charm quark and a light antiquark or the charge conjugate. The measurements cover the kinematic region of photon virtuality 2 < Q2 < 100 GeV2, inelasticity 0.05 < y < 0.7, D meson transverse momenta pt(D) ≥ 2.5 GeV and pseudorapidity |η(D)| ≤ 1.5. The identification of the D-meson decays and the reduction of the combinatorial background profit from the reconstruction of displaced secondary vertices by means of the H1 silicon vertex detector. The production of charmed mesons containing the light quarks u, d and s is found to be compatible with a description in which the hard scattering is followed by a factorisable and universal hadronisation process

    Inclusive production of D+, D-0, D-s(+) and D*(+) mesons in deep inelastic scattering at HERA

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    Lifestyle and dietary factors in the prevention of lethal prostate cancer

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