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Understanding the mechanism that controls cement hydration and its stages is a long-standing challenge. Over a decade ago, the mineral dissolution theory was adopted from geochemistry to explain the hydration rate evolution of alite. The theory is not fully accepted by the community and deserves further investigation. In this work, we apply Kinetic Monte Carlo (KMC) simulations with the mineral dissolution theory as a conceptual framework to investigate and discuss alite dissolution. We build a Kossel crystal model system and parameterize the dissolution activation energies and frequencies based on experimental data. The resulting KMC model is capable of reproducing the dissolution rate and activation energies as a function of the dissolution free energy. The simulations indicate that mineral dissolution theory easily explains the induction and acceleration stages due to a continuous increase of the reactive area as the etch pits open. However, the deceleration stage is hardly reconcilable with the mechanism suggested in the literature, i.e. dislocation coalescence. Still, within the mineral dissolution theory umbrella, we propose and discuss an alternative mechanism based on dislocation exhaustion. 

Abstract Over the last quarter century, increasing honey bee colony losses motivated standardized large-scale surveys of managed honey bees (Apis mellifera), particularly in Europe and the United States. Here we present the first large-scale standardized survey of colony losses of managed honey bees and stingless bees across Latin America. Overall, 1736 beekeepers and 165 meliponiculturists participated in the 2-year survey (2016–2017 and 2017–2018). On average, 30.4% of honey bee colonies and 39.6% of stingless bee colonies were lost per year across the region. Summer losses were higher than winter losses in stingless bees (30.9% and 22.2%, respectively) but not in honey bees (18.8% and 20.6%, respectively). Colony loss increased with operation size during the summer in both honey bees and stingless bees and decreased with operation size during the winter in stingless bees. Furthermore, losses differed significantly between countries and across years for both beekeepers and meliponiculturists. Overall, winter losses of honey bee colonies in Latin America (20.6%) position this region between Europe (12.5%) and the United States (40.4%). These results highlight the magnitude of bee colony losses occurring in the region and suggest difficulties in maintaining overall colony health and economic survival for beekeepers and meliponiculturists.