Vietnam has a population of 97 million people, a border shared with China — and no recorded deaths from COVID-19. Plus: Koala- and human-health researchers work together to discover a vaccine for chlamydia, and the month’s best science images.

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The largest urban plant farm in the world on a rooftop in Paris, France

The largest urban plant farm in the world on a rooftop in Paris, France

Credit: Bureau233/eyevine

The world’s largest urban rooftop farm opened to the public on 1 July. Located on top of an exhibition centre in southwest Paris, the farm stretches over 15,000 square metres and aims to produce several hundred kilograms of fruit, vegetables and spices each day. It will use space-saving methods such as aeroponics, in which plants are grown in vertical columns without soil and are fed liquid nutrients.

See more of the month’s sharpest science shots, selected by Nature’s photo team.

Nature | Leisurely scroll

Some 80% of donated lungs have to be discarded because of damage. But after researchers connected rejected lungs to pigs, the lungs recovered and were fit for transplant. The method revived lungs that ex vivo lung perfusion, the normal method of maintaining and repairing lungs outside the body, had failed to fix. “All of a sudden, [the lungs are] attached to a functioning liver, a functioning gut,” says thoracic surgeon Matthew Bacchetta. “We used a fairly standard immunosuppressive regimen and took these rejected lungs and showed that we could actually sustain them and make them better.” Researchers say the effect could work just as well if the lungs were connected to a human — allowing a person in need of a lung transplant to heal the lungs they require, themselves.

STAT | 6 min read

Reference: Nature Medicine paper

Features & opinion

The coronavirus pandemic has shaken our faith in urban life, notes author Andrew Robinson in his review of a book by historian Greg Woolf. Starting from Uruk, in Mesopotamia — arguably the first city ever — Woolf offers a deeply researched and ambitious natural history of the origins and growth of urbanism. Though written before the coronavirus pandemic, the book offers insight into how disease nudged the courses of great cities as they rose — and inevitably, fell.

Nature | 6 min read

Vaccine trials being run in Australia to protect koalas from chlamydia could help lead to a human vaccine, too. Chlamydia is ravaging the animals’ population (aided by habitat destruction and road kill). Animal- and human-health researchers are working together on projects that benefit both species. “You’re better off doing a bad experiment in koalas than a good experiment in mice,” says microbiologist Peter Timms. “We don’t need a vaccine for mice.”

The New York Times | 10 min read

Quote of the day

Locked down at home with a new baby, invasion ecologists Florencia Yannelli and Wolf-Christian Saul kicked off an experiment on their balcony. (Nature | 4 min read)

I can’t stop staring at this data-driven animation of New York City’s wind by artist Refik Anadol. It’s the latest of his Wind Data Paintings, and you can read all about how they’re created in this 2017 article in Vice.

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Flora Graham, senior editor, Nature Briefing

With contributions by David Cyranoski

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