пятница, 31 января 2020 г.

'Doomsday Clock' closer to midnight than ever

The Doomsday Clock on Thursday ticked down to 100 seconds to midnight, symbolizing the greatest level of peril to humanity since its creation in 1947 as the threat posed by climate change and a growing nuclear race loomed large.

'Doomsday Clock' closer to midnight than ever
"We are now expressing how close the world is to catastrophe in seconds – not hours, or even minutes," said
Rachel Bronson, president of the Bulletin of the Atomic Scientists in announcing the change
[Credit: Carolyn Kaster/Associated Press]
The danger level was compounded by information warfare and disruptive technologies ranging from deepfake video and audio to the militarization of space and the development of hypersonic weapons.

"We are now expressing how close the world is to catastrophe in seconds—not hours, or even minutes," said Rachel Bronson, president of the Bulletin of the Atomic Scientists, in announcing the change.

The decision on the clock is taken by panels of experts, including 13 Nobel laureates. It was originally set at seven minutes to midnight, and the previous worst—two minutes to midnight—held from 2018 to 2019 as well as 1953. The furthest it has ever been is 17 minutes, following the end of the Cold War in 1991.

On the nuclear front, the arms control boundaries that helped prevent catastrophe over the last half century are being dismantled and may be gone by next year, said subject expert Sharon Squassoni.

This includes the demise in 2019 of the Intermediate-Range Nuclear Forces (INF) Treaty, with the US and Russia entering a new competition to deploy once banned weapons. The US has suggested it won't extend New START, an arms reduction treaty signed in 2010.

"This year could see not just the complete collapse of the Iran nuclear deal," added Squassoni, with Tehran boosting its enrichment efforts.

And despite initial hopes US President Donald Trump's unorthodox approach to North Korea may produce results, no real progress ensued, said Squassoni, with Pyongyang instead vowing to press ahead with a new strategic weapon.

'Doomsday Clock' closer to midnight than ever
The Doomsday Clock on Thursday ticked down to 100 seconds to midnight
[Credit: Iris Royer De Vericourt/AFP]
On climate, two major UN summits fell dismally short of the action required to limit long-term warming to the goals laid out by the Paris Agreement that scientists say is necessary to prevent catastrophe.

The effects were already apparent in the record-breaking heat waves and floods India faced in 2019, and the wildfires that raged from the Arctic to Australia.

"If humankind pushes the climate into the opposite of an ice age," said Sivan Kartha, a scientist at the Stockholm Environmental Institute, "we have no reason to be confident that such a world will remain hospitable to human civilization."

Yet the experts took heart in mounting climate activism spearheaded by a youth movement that is spurring some governments to action.

Misinformation campaigns and fake news catalyzed by deepfake videos are potent threats to social cohesion, while the rise of AI weapons like drones that attack targets without human supervision create new uncertainty.

Russia meanwhile has announced a new hypersonic glide missile and the US is testing its own weapons that severely limit response times of targeted nations.

Space, long an arena for international cooperation, is also becoming increasingly militarized with multiple countries testing projectile and laser anti-satellite weapons and the US creating a new military branch, the Space Force.

"We ask world leaders to join us in 2020 as we work to pull humanity back from the brink," said Mary Robinson, chair of The Elders leadership group and former president of Ireland.

"Now is the time to come together—to unite and to act."

Source: AFP [January 23, 2020]

* This article was originally published here

Finely tuned nervous systems allowed birds and mammals to adopt smoother strides

Since the 1900s, neuroscientists have known that the peripheral nervous systems of tetrapods (four-footed animals) vary greatly, but how these differences affect the way that animals walk, run, or move has not been well understood. Now, a study published in the Journal of Experimental Biology, authored by a New York Institute of Technology anatomy professor, suggests that neuromuscular adaptations in mammals and birds may have allowed them to become more nimble than reptiles and amphibians.

Finely tuned nervous systems allowed birds and mammals to adopt smoother strides
Golgi tendon organs in reptiles and amphibians vs. birds and mammals
[Credit: Michael Granatosky]
"This research could explain why tigers have a much smoother walk than crocodiles, which lumber and drag their abdomens, and perhaps one reason why today's humans have evolved to walk with such uniform steps," says lead author Michael Granatosky, Ph.D., assistant professor of Anatomy at New York Institute of Technology College of Osteopathic Medicine (NYITCOM).

Tetrapods have small receptors in their muscles called Golgi tendon organs, which protect muscles from forces during locomotion (walking) and other physical activity. When muscle tension becomes dangerous, these receptors signal the nervous system to produce reflexes that release tension and prevent injury.

Amphibians and reptiles, which diverged from early tetrapods before mammals and birds, have freeform Golgi tendons located further from the muscle-tendon junction, suggesting that they detect stress across the entire muscle. In contrast, birds and mammals have encapsulated Golgi tendon organs set directly at the muscle-tendon junction, signifying an ability to detect tension in precise muscle areas, which would allow for more controlled motion. Now, researchers pose that birds and mammals owe their agile strides to these finely tuned receptors.