Nels Johnson

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The cover illustration portrays a landscape in which terrestrial and marine protected areas are connected through corridors of natural or restored habitat and surrounded by buffer and multiple-use zones to ensure the long-term conservation of biodiversity. In this vision, landscapes are managed for ecosystem services such as clean water, soil stability,(More)
The Venus Science and Technology Definition Team (STDT) was formed by NASA to look at science objectives, mission architecture, science investigations, and instrument payload for a Flagship-class mission to Venus. This $3-4B mission, to launch in the 2020-2025 timeframe, should revolutionize our understanding of how climate works on terrestrial planets,(More)
Female mating frequency is one of the key parameters of social insect evolution. Several hypotheses have been suggested to explain multiple mating and considerable empirical research has led to conflicting results. Building on several earlier analyses, we present a simple general model that links the number of queen matings to variance in colony performance(More)
Introduction: The Venus Science and Technology Definition Team (STDT) was created by NASA's Science Mission Directorate to formulate the science goals and objectives, and to design the mission architecture , science investigations, and instrument payload for a Flagship-class mission to Venus. It was also tasked to develop a prioritized technology roadmap to(More)
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