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This soft robot runs on a battery fluid that circulates around its body.Credit: James Pikul

A robotic fish is powered by ‘robot blood’ that stores energy like a battery and also physically moves the fins. The innovation increased the amount of energy stored in the robot by 325%, compared with a machine that has a separate battery and hydraulic-fluid system — saving on weight and power requirements.

Nature | 2 min read

The US Environmental Protection Agency (EPA) has finalized its plan to relax limits on greenhouse-gas emissions from power plants. The EPA’s Affordable Clean Energy rule will allow states to set their own emissions-reduction goals. It also focuses on the use of energy-efficiency technologies at individual power plants — by contrast with an Obama-era plan, which would have set goals for each state and required energy producers and utility companies to work together to find solutions. The government says the rule will incentivize new technologies without undue regulatory pressure, but environmentalists say it’s a blatant attempt to prop up coal plants. The new rule will almost certainly face lawsuits.

Nature | 4 min read

The United Nations predicts that there will be 9.7 billion people on Earth by 2050 — slightly below the previous estimates issued two years ago. India will overtake China as the most populous country in or near 2027, but worldwide, the overall population growth rate will continue to fall. Twenty-seven countries have seen their populations drop since 2010, as people leave to seek a better life, flee from conflict or have fewer children.

Financial Times | 8 min read

FEATURES & OPINION

What will it take to make gene editing a human embryo — causing changes that would be inherited by future generations — acceptable as a clinical tool? Nature asked researchers and other stakeholders which edits they think are safe, how clinical trials would have to change — and how many mistakes are too many.

Nature | 13 min read

The Nature Index 2019 Annual Tables reveal the institutions that dominate top-notch science research. There are lots of qualities that could be used to define greatness, but the Tables rely on just one: the share of articles published in 82 prestigious scientific journals, selected by an independent panel of scientists and tracked by the Nature Index database.

• The Chinese Academy of Sciences maintains its stronghold as the world’s most prolific publisher of high-quality research. It also recorded the largest growth in publications among the top 10 institutions .

• What happens when you consider how much of an institution’s research is high quality, as a proportion of its total output? In this year's normalized table you see the Cold Spring Harbor Laboratory, ranked 345th overall, rise to number one. Institutes from Austria, India and Israel also make big leaps.

• The Nature Index visual guide shows the leading institutions by subject, and reveals that NASA, Caltech, the University of Colorado, Boulder, and the US Geological Survey are major outliers that lead the list in Earth and environmental sciences without breaking the overall top 10.

Nature Index | Read the full collection

Nextjournal, Binder and Code Ocean offer to help researchers publish “perfectly reproducible” articles by sharing not only their code and data, but also the computing environments used to execute them. But the tools can be difficult to get up and running. Nature’s expert on all things tech, Jeffrey Perkel, wrestles his own code into each one to see what they can do .

Nature Index | 8 min read