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To estimate rainfall in honeycomb-like structure places that lack ground-based (pictured) that has excellent rain gauges, researchers electrical conductivity, unlike Popular articles on social media rely on satellite data of most other self-assembled SOCIAL SELECTION atmospheric moisture, but organic–inorganic systems. this is notoriously inaccurate. The team studied the material Maths reality check resonates online Luca Brocca at the National only in bulk form, but say Research Council in Perugia, that the results could be Biologists of all stripes are sharing an essay by Harvard Italy, and his colleagues even better if the polymer University mathematician-turned-biologist Jeremy developed an algorithm that was in two-dimensional Gunawardena that makes a sobering observation: the calculates rainfall amounts on sheets, perhaps leading to mathematical equations at the core of many biological models the basis of satellite data on more efficient solar cells and fail to reflect . He argues that the components of all soil moisture. They compared supercapacitors. quantitative models should be verifiable and, most of all, the their estimates with rain-gauge J. Am. Chem. Soc. http://doi.org/ conclusions should be falsifiable. Or, in his words: “Stick the data and found that their spj (2014) model’s neck out.” Jason Moore, a geneticist at Dartmouth method accurately estimates College in , tweeted: “This paper is so good rainfall in several regions GENOMICS I am actually printing it out”— high praise in the paperless age. around the world. BMC Biol. 12, 29 (2014) Moreover, their algorithm When brown and is better than a state-of- polar bears split the-art method at detecting Based on data from .com. NATURE.COM light rainfall events and Polar bears evolved adaptations Altmetric is supported by Macmillan For more on precipitation at high latitudes. specific to the Arctic in fewer AScienceltmetric and Education, which owns popular papers: J. Geophys. Res. Atmos. than 20,500 generations, and Nature Group. go.nature.com/mpqjve http://doi.org/sp7 (2014) diverged from brown bears much more recently than is MATERIALS sometimes claimed. Massachusetts, analysed Rasmus Nielsen at the the emissions of binary- Graphene analogue University of California, star systems, in which only Berkeley, and his colleagues one of the two stars in the

NAWAZISH NAQVI NAWAZISH carries current sequenced the genomes system hosted an exoplanet. A self-assembling polymer that of 79 polar bears (Ursus Comparing the differences forms thin films and conducts maritimus) and 10 brown between the emissions of the electricity could beat graphene bears (Ursus arctos) and found stars in each pair allowed as a candidate material for that the two species diverged the authors to measure the flexible electronics. between 343,000 and 479,000 influence of the exoplanet on Graphene, made of an years ago. its host star. Using X-ray data atom-thick sheet of carbon, Many of the genes under the from the Chandra and XMM- is flexible but cannot be greatest selection pressure in Newton space telescopes, used as a semiconductor in the polar bear are associated the researchers found that University School of transistors because it lacks a with the cardiovascular the stars hosting hot Jupiters Medicine in Atlanta, Georgia, ‘band gap’. Mircea Dincă at system. In particular, this showed more magnetic and Robert Graham of the Massachusetts Institute bear seems to have evolved activity than their planet-free the Victor Chang Cardiac of Technology in Cambridge modifications in its vascular companions. Research Institute in and his colleagues mixed system that allow the animal to Magnetic activity increases Sydney, Australia, and their nickel with an organic tolerate an extremely fatty diet with rotation, so the authors colleagues labelled heart compound called HITP and made up mostly of blubbery suggest that the gravitational muscle cells of baby mice ammonia in water to produce seal meat. influence of the hot Jupiters with a chemical. When the a graphene-like structure with Cell http://doi.org/sp3 (2014) may have counteracted the mice were 15 days old, the the important band gap. For a longer story on this research, natural slowing of their host number of cardiomyocytes The ingredients self- see go.nature.com/zovyry stars’ spin over time. (pictured, red) increased by

DENNIS SHEBERLA assemble into a flat, Astron. Astrophys. 565, L1 (2014) about 40%. ASTROPHYSICS It had previously been BIOLOGY thought that cardiomyocytes Big planets could stopped replicating just after alter star rotation Thyroid makes birth. The findings suggest young hearts grow that giving thyroid hormone Massive planets with close-in to babies with heart defects orbits — also known as hot A surge of thyroid hormone might help to repair the Jupiters — may influence the just before adolescence organ. rotation and surface activity of causes mouse hearts to grow Cell 157, 795–807 (2014) their host stars. drastically, suggesting that Katja Poppenhaeger and the organ may be easier to NATURE.COM Scott Wolk at the Harvard- regenerate than previously For the latest research published by 500 nm Smithsonian Center for thought. Nature visit: Astrophysics in Cambridge, Ahsan Husain of Emory www.nature.com/latestresearch

15 MAY 2014 | VOL 509 | NATURE | 263 © 2014 Limited. All rights reserved