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New tech 'MERMAIDS' can detect earthquakes before they wreak destruction

A network of devices called MERMAIDs is taking seismographs where they've never been.

(Princeton University)
  • Most of the ocean floor is inaccessible to seismologists.
  • Much can be learned about the interior of Earth by listening to earthquakes.
  • Ingenious new floating sensors are changing the ocean seismology game.

They're called MERMAIDs. They're drifting seismometers that listen to movements of Earth's crust pulsing through the waters of previously unmonitored reaches of the oceans, the two-thirds of the Earth that's inaccessible to stationary seismic detectors.

Scientists can glean a tremendous amount of information from seismic data about the inside of the planet. If they have that data, that is. The first results of their journeys were published this month in Scientific Reports (paywall). They offer an unprecedented peek at what's going on beneath the Galapagos.

9 MERMAIDs floating free

Image source: Yann Hello, University of Nice

The MERMAID project is the brainchild of Princeton geoscientist Frederik Simons. "Imagine a radiologist forced to work with a CAT scanner that is missing two-thirds of its necessary sensors," he tells Phys.org. He and colleague Guust Nolet have been developing their system for 15 years.

Each "MERMAID" is a floating seismometer/hydrophone set free to drift where it will, and together they form a seismographic network. "MERMAID" stands for "Mobile Earthquake Recording in Marine Areas by Independent Divers."

They generally float at a depth of 1,500 meters. But when they pick up audio that may signify the start of an earthquake, they rise to the surface, taking no longer than 95 minutes to get there, poke their heads out of the water to acquire their location via GPS, and transmit the data they've collected.

The nine MERMAIDs have just completed their first two-year tour of duty.

What the MERMAIDs found

This shows the speed of seismic waves moving through the Earth from the surface at the top of the cross-section down to about 2,890 km deep at its bottom edge. Darker colors signify slower wave movement. Image source: Princeton University

The MERMAIDs drifted through an area ranging from about 20° north to 20° south centered on the Galápagos Islands. Their data revealed the volcanoes on the islands are fed hot rock via a narrow conduit that extends downward to about 1,200 miles (1,900 km). Such a deep ocean "mantle plume," a phrase coined by geophysicist W. Jason Morgan, who hypothesized their existence in 1971, has never been imaged in detail prior to the deployment of the MERMAIDs.

The high temperatures they recorded is of special interest. Ever since observations have contradicted Lord Kelvin's 19th-century proposal that the Earth should be cooling quickly, scientists have wondered why the Earth has somehow managed to remain at a fairly constant temperature instead. The new research suggests an answer.

In a Princeton University press release, Nolet explained:

"These results of the Galápagos experiment point to an alternative explanation: the lower mantle may well resist convection, and instead only bring heat to the surface in the form of mantle plumes such as the ones creating Galápagos and Hawaii."

Next up is a new fleet of some 50 MERMAIDs to be released in the South Pacific with the aim of learning more about the plume region beneath Tahiti. That project will be led by Chen Yongshun of Southern University of Science and Technology, who enthuses, "Stay tuned! There are many more discoveries to come."

Hulu's original movie "Palm Springs" is the comedy we needed this summer

Andy Samberg and Cristin Milioti get stuck in an infinite wedding time loop.

Gear
  • Two wedding guests discover they're trapped in an infinite time loop, waking up in Palm Springs over and over and over.
  • As the reality of their situation sets in, Nyles and Sarah decide to enjoy the repetitive awakenings.
  • The film is perfectly timed for a world sheltering at home during a pandemic.
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Two MIT students just solved Richard Feynman’s famed physics puzzle

Richard Feynman once asked a silly question. Two MIT students just answered it.

Surprising Science

Here's a fun experiment to try. Go to your pantry and see if you have a box of spaghetti. If you do, take out a noodle. Grab both ends of it and bend it until it breaks in half. How many pieces did it break into? If you got two large pieces and at least one small piece you're not alone.

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Our ‘little brain’ turns out to be pretty big

The multifaceted cerebellum is large — it's just tightly folded.

Image source: Sereno, et al
Mind & Brain
  • A powerful MRI combined with modeling software results in a totally new view of the human cerebellum.
  • The so-called 'little brain' is nearly 80% the size of the cerebral cortex when it's unfolded.
  • This part of the brain is associated with a lot of things, and a new virtual map is suitably chaotic and complex.

Just under our brain's cortex and close to our brain stem sits the cerebellum, also known as the "little brain." It's an organ many animals have, and we're still learning what it does in humans. It's long been thought to be involved in sensory input and motor control, but recent studies suggests it also plays a role in a lot of other things, including emotion, thought, and pain. After all, about half of the brain's neurons reside there. But it's so small. Except it's not, according to a new study from San Diego State University (SDSU) published in PNAS (Proceedings of the National Academy of Sciences).

A neural crêpe

A new imaging study led by psychology professor and cognitive neuroscientist Martin Sereno of the SDSU MRI Imaging Center reveals that the cerebellum is actually an intricately folded organ that has a surface area equal in size to 78 percent of the cerebral cortex. Sereno, a pioneer in MRI brain imaging, collaborated with other experts from the U.K., Canada, and the Netherlands.

So what does it look like? Unfolded, the cerebellum is reminiscent of a crêpe, according to Sereno, about four inches wide and three feet long.

The team didn't physically unfold a cerebellum in their research. Instead, they worked with brain scans from a 9.4 Tesla MRI machine, and virtually unfolded and mapped the organ. Custom software was developed for the project, based on the open-source FreeSurfer app developed by Sereno and others. Their model allowed the scientists to unpack the virtual cerebellum down to each individual fold, or "folia."

Study's cross-sections of a folded cerebellum

Image source: Sereno, et al.

A complicated map

Sereno tells SDSU NewsCenter that "Until now we only had crude models of what it looked like. We now have a complete map or surface representation of the cerebellum, much like cities, counties, and states."

That map is a bit surprising, too, in that regions associated with different functions are scattered across the organ in peculiar ways, unlike the cortex where it's all pretty orderly. "You get a little chunk of the lip, next to a chunk of the shoulder or face, like jumbled puzzle pieces," says Sereno. This may have to do with the fact that when the cerebellum is folded, its elements line up differently than they do when the organ is unfolded.

It seems the folded structure of the cerebellum is a configuration that facilitates access to information coming from places all over the body. Sereno says, "Now that we have the first high resolution base map of the human cerebellum, there are many possibilities for researchers to start filling in what is certain to be a complex quilt of inputs, from many different parts of the cerebral cortex in more detail than ever before."

This makes sense if the cerebellum is involved in highly complex, advanced cognitive functions, such as handling language or performing abstract reasoning as scientists suspect. "When you think of the cognition required to write a scientific paper or explain a concept," says Sereno, "you have to pull in information from many different sources. And that's just how the cerebellum is set up."

Bigger and bigger

The study also suggests that the large size of their virtual human cerebellum is likely to be related to the sheer number of tasks with which the organ is involved in the complex human brain. The macaque cerebellum that the team analyzed, for example, amounts to just 30 percent the size of the animal's cortex.

"The fact that [the cerebellum] has such a large surface area speaks to the evolution of distinctively human behaviors and cognition," says Sereno. "It has expanded so much that the folding patterns are very complex."

As the study says, "Rather than coordinating sensory signals to execute expert physical movements, parts of the cerebellum may have been extended in humans to help coordinate fictive 'conceptual movements,' such as rapidly mentally rearranging a movement plan — or, in the fullness of time, perhaps even a mathematical equation."

Sereno concludes, "The 'little brain' is quite the jack of all trades. Mapping the cerebellum will be an interesting new frontier for the next decade."

Economists show how welfare programs can turn a "profit"

What happens if we consider welfare programs as investments?

A homeless man faces Wall Street

Spencer Platt/Getty Images
Politics & Current Affairs
  • A recently published study suggests that some welfare programs more than pay for themselves.
  • It is one of the first major reviews of welfare programs to measure so many by a single metric.
  • The findings will likely inform future welfare reform and encourage debate on how to grade success.
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