Category: Science Articles

Starting in the 1960s, doctors attempted transplants of kidneys, hearts, and livers from baboons and chimpanzees—humans’ closest genetic relatives—into people. But the organs failed within weeks, if not days, due to rejection or infection. These efforts were largely abandoned after “Baby Fae,” an infant with a fatal heart condition, died within a month of receiving a baboon heart transplant in 1984. (Her immune system rejected the heart.) 

By the 1990s, researchers turned their attention to pigs. Their organs are more similar in size to human ones and take only months to grow to a size suitable for donation. Unlike primates, there’s less concern about them passing on HIV-like viruses to patients (though pigs harbor different kinds of viruses). And scientists thought pig donors would be more accepted by the public, since they are already raised for agriculture.

But biological differences between pigs and humans make transplantation much more challenging. So

For centuries, mathematicians have sought to understand and model the motion of fluids. The equations that describe how ripples crease the surface of a pond have also helped researchers to predict the weather, design better airplanes, and characterize how blood flows through the circulatory system. These equations are deceptively simple when written in the right mathematical language. However, their solutions are so complex that making sense of even basic questions about them can be prohibitively difficult.

Perhaps the oldest and most prominent of these equations, formulated by Leonhard Euler more than 250 years ago, describe the flow of an ideal, incompressible fluid: a fluid with no viscosity, or internal friction, and that cannot be forced into a smaller volume. “Almost all nonlinear fluid equations are kind of derived from the Euler equations,” said Tarek Elgindi, a mathematician at Duke University. “They’re the first ones, you could say.”

Yet much

This story originally appeared in The Guardian and is part of the Climate Desk collaboration.

Scientists have discovered a record number of dead fir trees in Oregon, a foreboding sign of how drought and the climate crisis are ravaging the American West.

A recent aerial survey found that more than a million acres of forest contain trees that have succumbed to stressors exacerbated by a multiyear drought. Images released by the US Forest Service show Oregon’s lush green expanses dotted with ominous swathes of red.

“It is stunning,” said Daniel DePinte, an aerial survey program manager with the Forest Service who led the agency’s Pacific Northwest region aerial survey, noting that this year saw the highest mortality rate for firs in this area in history. These evergreen conifers are less able to survive in drought conditions than other heartier trees that line the landscapes.

He and his colleagues scanned

A few weeks ago, Sports Illustrated tweeted this video of Golden State Warriors point guard Steph Curry that instantly went viral. It shows him taking a shot at the basket—from the far side of the court. The ball goes in. OK, I can believe that. He’s a famously great shooter. But then he turns around and grabs another ball and takes another shot … and makes it. And then again. And again. And a fifth time.

So is it real or fake? Let’s use statistics and physics to find out.

Basic Probability

Physicists don’t usually jump right into the most complicated version of a problem. Instead, they do a rough estimation, often called a “back of the envelope” calculation. So let’s make some approximations about the probability of making five full-court shots in a row.

We can start with a simple experiment that you can try at home—you just

In June, a vast new vertical farm opened on the outskirts of the English town Bedford. At a swanky opening event, members of the UK Parliament heard that the gleaming facility would one day produce 20 million plants annually. It was the latest opening for Infarm, a European vertical farming company that had raised over $600 million in venture capital funding, promising a future where vegetables are grown in high-tech warehouses stacked with LED lights rather than in open fields or greenhouses.

But now the future of the Bedford farm looks less than gleaming. On November 29, Infarm’s founders emailed its workforce to announce they were laying off “around 500 employees”—more than half of the workforce. The email detailed the firm’s plans to downsize its operations in the UK, France, and the Netherlands, and concentrate on countries where it had stronger links to retailers and a higher chance of eventually