Highlights - Week of December 13th

PNAS Highlights is a biweekly newsletter from Proceedings of the National Academy of Sciences. This week we discuss how green ammonia could produce climate-friendly ways to store energy and fertilize farms, explore tropical forests in the Anthropocene in the latest Science Sessions episode, and study timescales of Stone Age antiquities. Click [here]( for articles from the Special Feature on Dynamics of Political Polarization. Front Matter Click [here]( to explore the full Front Matter portal. [Core Concept: Green ammonia could produce climate-friendly ways to store energy and fertilize farms]( [Inner Workings: Can feeding the gut microbiome treat malnutrition?]( [Journal Club: Stem cell niche within plant callus tissue drives organ regeneration]( Science Sessions [Tropical forests in the Anthropocene – Part 1]( Latest Research from PNAS Click [here]( to view this week's research highlights and [here]( for last week’s. [Timescales of Stone Age antiquities]( [Temperature and aging in frogs and toads]( [Canine tooth sexual dimorphism in human evolution]( Want more PNAS research? Click [here]( to view content from this week's issue. [Twitter]( [Facebook]( [Website]( PNAS Highlights is a biweekly newsletter, featuring a curated selection of science news and research from the journal. Have feedback for us? Respond to this email and let us know what you think! Copyright © 2021 Proceedings of the National Academy of Sciences, All rights reserved. Our mailing address is: 500 5th St NW, DC, 20001 Want to change how you receive these emails? You can [update your preferences]( or [unsubscribe from this list](.