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Nitrogen (N) is an essential but generally limiting nutrient for biological systems. Development of the Haber-Bosch industrial process for ammonia synthesis helped to relieve N limitation of agricultural production, fueling the Green Revolution and reducing hunger. However, the massive use of industrial N fertilizer has doubled the N moving through the global N cycle with dramatic environmental consequences that threaten planetary health. Thus, there is an urgent need to reduce losses of reactive N from agriculture, while ensuring sufficient N inputs for food security. Here we review current knowledge related to N use efficiency (NUE) in agriculture and identify research opportunities in the areas of agronomy, plant breeding, biological N fixation (BNF), soil N cycling, and modeling to achieve responsible, sustainable use of N in agriculture. Amongst these opportunities, improved agricultural practices that synchronize crop N demand with soil N availability are low-hanging fruit. Crop breeding that targets root and shoot physiological processes will likely increase N uptake and utilization of soil N, while breeding for BNF effectiveness in legumes will enhance overall system NUE. Likewise, engineering of novel N-fixing symbioses in non-legumes could reduce the need for chemical fertilizers in agroecosystems but is a much longer-term goal. The use of simulation modeling to conceptualize the complex, interwoven processes that affect agroecosystem NUE, along with multi-objective optimization, will also accelerate NUE gains. 

Intelligent Virtual Agents (IVAs) received enormous attention in recent years due to significant improvements in voice communication technologies and the convergence of different research fields such as Machine Learning, Internet of Things, and Virtual Reality (VR). Interactive conversational IVAs can appear in different forms such as voice-only or with embodied audio-visual representations showing, for example, human-like contextually related or generic three-dimensional bodies. In this paper, we analyzed the benefits of different forms of virtual agents in the context of a VR exhibition space. Our results suggest positive evidence showing large benefits of both embodied and thematically related audio-visual representations of IVAs. We discuss implications and suggestions for content developers to design believable virtual agents in the context of such installations.