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The inequity aversion model is fundamental to explaining the motivation of voluntary contribution behavior. Yet, the empirical studies limit the research on the inequity-aversion to small groups due to the difficulty of accounting for each individual's payoff in the decision-making process for large group sizes. To overcome the technical barrier of estimating expected payoffs with large group sizes and various marginal returns, we adopt the Quantal Response Equilibrium estimation method that allows for an individual's contribution to be impacted by their social preferences, i.e., inequality aversion, altruism, and bounded rationality. Our theoretical model identifies the equilibrium strategy of contribution. Using Bayesian inference via Markov Chain Monte Carlo, the experimental results show people are significantly worse off when they contribute more or less than others, meaning social equality promotes public good provisions. We find that marginal per capita return and group size play important roles in people's contribution decisions, and the effect of marginal per capita return on contributions is stronger than that of group size. [ABSTRACT FROM AUTHOR]

The recent remarkable increase in induced seismicity in Western Canada has been largely attributed to hydraulic fracturing in unconventional reservoirs. The nucleation of large magnitude events has been demonstrated to be closely linked to site-specific geological and operational factors. A mitigation strategy of fracturing-induced seismicity concerning both factors has not been well investigated. In this paper, a comprehensive investigation of risk mitigations from induced seismicity is conducted based on the formation overpressure, distance to Precambrian basement, proximity to faults, fracturing job size and safe hydraulic fracture-fault distance. It is found that the middle-south region near Crooked Lake is an optimal region for fracturing operations with low formation pressure, a great distance to the basement and relatively fewer pre-existing faults. A field case study suggests that fracturing operations of three new horizontal wells are successful with low magnitude induced events and with high production performance, demonstrating the applicability of a comprehensive approach of seismicity risk mitigations. Such an approach can be applied to other field cases to mitigate the potential fracturing-induced seismicity in unconventional reservoirs. [ABSTRACT FROM AUTHOR]

Organocatalyzed asymmetric Friedel–Craft reactions have enabled the rapid construction of chiral molecules with highly enantioselectivity enriching the toolbox of chemists for producing complex substances. Here, we report N-heterocyclic carbene-catalyzed asymmetric indole Friedel–Crafts alkylation-annulation with α,β-unsaturated acyl azolium as the key intermediate, affording a large variety of indole-fused polycyclic alkaloids with excellent diastereo- and enantioselectivities. The reaction mechanism is also investigated, and the reaction products can be easily converted to highly functionalized indole frameworks with different core structures. Indole-fused polycyclic alkaloids are present in numerous bioactive natural products. Here an enantioselective N-heterocyclic carbene-catalysed Friedel–Crafts alkylation/annulation cascade using acyl azolium salts as the electrophile provides access to these products with high stereoselectivity. [ABSTRACT FROM AUTHOR]