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Using a coalescence–dispersion model of the continuous flow-stirred tank reactor (CSTR), we study the effect of premixed vs nonpremixed reactant flows on chemical bistability. The region of bistability is smaller for segregated feed streams than for a fully premixed feed stream. The transition from flow branch to thermodynamic branch is particularly sensitive to the feed stream configuration. [ABSTRACT FROM AUTHOR]

The incorporation of natural, non-crop vegetation in and around farmlands is a common practice in many agroecosystems, and may provide benefits both for production and conservation of biological diversity. In coffee agroecosystems, non-crop vegetation is routinely incorporated in the form of shade trees or forest habitat in and around coffee plants. In order to assess the importance of adjacent forest habitat to Hymenoptera associated with coffee farms, we sampled Hymenoptera on twelve coffee farms in the Tarrazú region in the central highlands of Costa Rica. Six of the farms were adjacent to forest habitat, and six were spatially isolated from forest; farms were sampled in both the dry (flowering) and the rainy (non-flowering) seasons. On adjacent farms, Hymenoptera samples taken in coffee and forest habitat were also compared. Finally, we also conducted pollinator observations in each type of farm, comparing Hymenoptera visitors to coffee plants in adjacent vs. isolated farms. Our results revealed an interaction in hymenopteran diversity between farm isolation and season, suggesting that both forest and coffee habitats play important roles at different times for Hymenoptera, especially bees. [ABSTRACT FROM AUTHOR]