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Figs and fig wasps have evolved to help each other out: Fig wasps lay their eggs inside the fruit where the wasp larvae can safely develop, and in return, the wasps pollinate the figs.

But what happens when a wasp lays its eggs but fails to pollinate the fig?

The trees get even by dropping those figs to the ground, killing the baby wasps inside, reports a Cornell and Smithsonian Tropical Research Institute study published in the Proceedings of the Royal Society B: Biological Sciences (published online Jan. 13).

The findings suggest that when one species in a mutually beneficial relationship fails to hold up its end of the bargain, sanctions may be a necessary part of maintaining the relationship.

"We want to know what forces maintain this 80 million-year-old mutualism between figs and their wasp pollinators," said lead author Charlotte Jandér, a Cornell graduate student in neurobiology and behavior, who conducted the study as a Smithsonian Tropical Research Institute predoctoral fellow. Edward Allen Herre, a staff scientist at the Smithsonian institute in Panama, co-authored the paper.

"What prevents the wasps from cheating and reaping the benefits of the relationship without paying the costs?" Jandér added.

More than 700 species each of fig trees and wasps have co-evolved in the tropics worldwide, with each fig tree species having its own species of pollinating wasp. Jandér worked on six fig tree-fig wasp pairs for the study. Some wasp species passively carry pollen that sticks to their bodies, while others actively collect pollen in special pouches.

The researchers found that in passively pollinated pairings, the tree almost never aborted its fruit, and the wasp always carried pollen. However, the researchers found that in actively pollinated pairings, where the wasp needs to expend energy to collect pollen, the tree dumped the fruit and killed the offspring when the wasps did not carry pollen.

The researchers also found that among the actively pollinated fig species, pollen-free wasps were much more common when the trees had weak sanctions.

"Sanctions seem to be a necessary force in keeping this and other mutually beneficial relationships on track when being part of a mutualism is costly," said Jandér. "In our study, we saw less cheating when sanctions were stronger. Similar results have been found among human societies and social insects. It is very appealing to think that the same general principles could help maintain cooperation both within and among species."

The study was supported by the Cornell Graduate School and Smithsonian Tropical Research Institute.

Thanks, phytopankton, for producing 90% of the world's oxygen!

How Reddit ranking algorithms work

Hysteresis is the dependence of a system not just on its current environment but also on its past. This dependence arises because the system can be in more than one internal state. To predict its future evolution, either its internal state or its history must be known.[1] If a given input alternately increases and decreases, the output tends to form a loop as in Fig. 1. However, loops may also occur because of a dynamic lag between input and output. Often, this effect is also referred to as hysteresis, or rate-dependent hysteresis. This effect disappears as the input changes more slowly, so many experts do not regard it as true hysteresis.

Hysteresis occurs in ferromagnetic materials and ferroelectric materials, as well as in the deformation of some materials (such as rubber bands and shape-memory alloys) in response to a varying force. In natural systems hysteresis is often associated with irreversible thermodynamic change. Many artificial systems are designed to have hysteresis: for example, in thermostats and Schmitt triggers, hysteresis is produced by positive feedback to avoid unwanted rapid switching. Hysteresis has been identified in many other fields, including economics and biology.

Check out the digital channel!

Remember the movie Brainstorm? Imagine watching someone�s dream, or tapping directly into the mind of a coma patient. University of California, Berkeley scientists claim they have finally achieved this classic futuristic movie �oemind reading” trope. Sorta.

They�re using functional Magnetic Resonance Imaging (fMRI) and computational models to decode and reconstruct people�s dynamic visual experiences.

So far, the technology can only reconstruct movie clips you�ve already viewed. But they claim that the breakthrough paves the way for reproducing the movies inside our heads that no one else sees, such as dreams and memories. �oeThis is a major leap toward reconstructing internal imagery,” said Professor Jack Gallant, a UC Berkeley neuroscientist and coauthor of the study. �oeWe are opening a window into the movies in our minds.”

OK, now I�m getting kinda creeped out over here.

Communicating with comatose patients

But wait, here�s the plus side: eventually, the researchers say, the technology could allow us to see into the minds of people who cannot communicate verbally, such as stroke victims, coma patients, and people with neurodegenerative diseases. It may also lay the groundwork for a brain-machine interface, so people with cerebral palsy or paralysis, for example, can guide computers with their minds.

However, researchers quickly assure us that the technology is decades away from allowing mad scientists to read your thoughts and intentions.

They say.

How it works

Set in a world with memory implants, Robin Williams plays a cutter, someone with the power of final edit over people's recorded histories (credit: Lions Gate Entertainment)

Gallant and fellow researchers previously recorded brain activity in the visual cortex while a subject viewed black-and-white photographs. They then built a computational model that enabled them to accurately predict which picture the subject was looking at.

In their latest experiment, they�ve solved the hard problem: actually decoding brain signals generated by moving pictures, the researchers report.

�oeOur natural visual experience is like watching a movie,” said Shinji Nishimoto, lead author of the study and a post-doctoral researcher in Gallant�s lab. �oeIn order for this technology to have wide applicability, we must understand how the brain processes these dynamic visual experiences.”

The Cell: A therapist enters the mind of a serial killer (credit: New Line Cinema)

Nishimoto and two other research team members served as subjects for the experiment, because the procedure requires volunteers to remain still, inside the MRI scanner, for hours at a time.

They watched two separate sets of Hollywood movie trailers, while fMRI was used to measure blood flow through the visual cortex, the part of the brain that processes visual information.

On the computer, the brain was divided into small, three-dimensional cubes known as volumetric pixels, or voxels. �oeWe built a model for each voxel that describes how shape and motion information in the movie is mapped into brain activity,” Nishimoto said.

Strange Days: An ex-cop who now deals with data-discs containing recorded memories and emotions receives a disc that contains the memories of a murderer (credit: Lightstorm Entertainment)

Reconstructing brain movies

The brain activity, recorded while subjects viewed the first set of clips, was fed into a computer program that learned, second by second, to associate visual patterns in the movie with the corresponding brain activity. Brain activity evoked by the second set of clips was used to test the movie reconstruction algorithm.

This was done by feeding 18 million seconds of random YouTube videos into the computer program so that it could predict the brain activity that each film clip would most likely evoke in each subject.

Wait, five hours having to watch videos of dogs drinking cola, sneezing pandas, and kids biting fingers? These guys are freaking heroes!

Finally, the 100 clips that the computer program decided were most similar to the clip that the subject had probably seen were merged to produce a blurry yet continuous reconstruction of the original movie.

Reconstructing movies using brain scans has been challenging because the blood flow signals measured using fMRI change much more slowly than the neural signals that encode dynamic information in movies, the researchers said. (Apparently. that�s why most previous attempts to decode brain activity have been limited static images.)

�oeWe addressed this problem by developing a two-stage model that separately describes the underlying neural population and blood flow signals,” Nishimoto said.

Ultimately, Nishimoto said, �oeWe need to know how the brain works in naturalistic conditions. For that, we need to first understand how the brain works while we are watching movies.”

Uh, maybe they should switch to Netflix this time. Hmm … can you eat popcorn in an MRI machine?

Ref.

The title of Bjork's new album came to her after she read a book by neurologist Oliver Sachs about the mind's empathy for music.

"He called it 'musicophilia,' she says. "Obviously, I make music, but I wanted to do a project about nature. So I thought, if I call it Biophilia, it's sort of empathy with nature."

So there are song titles like "Solstice," "Dark Matter" and "Crystalline." The lyrics actually touch on processes in nature �" for instance, how crystals grow.

During the time that Bjork was writing Biophilia, the iPad came out. Bjork says she was intrigued by the touch-screen technology and the creative possibilities it presented. She'd seen music apps before, but found most of them pretty superficial �" just updates about tours or an extra interview. She says she wanted to go beyond that.

"The interactiveness goes really to the core of the music, the structure of the song," Bjork says. "It's not just something like an accessory. ... It is the song."

Bjork fans with iPads or iPhones (there's no Android version yet) can download a main app for Biophilia that's free. You tap on it and open up to a black background with white, glowing starlike objects. Using your fingers to swipe and tap, the universe expands and turns, and bits of music and songs emerge.

Each song has its own star. You tap on it, and you can buy its app for $1.99 from the iTunes Store. Each one has essays about music and science, and each interacts with its song in a different way. Take "Thunderbolt," whose arpeggiated bass line you can change by tapping on a lightning icon.

"You change the speed of the arpeggio, or the range," Bjork says. "Basically, you're like this crazy lightning bass player."

Songs As Games

In "Virus," Bjork turns a virus into a sort of natural femme fatale, to create a narrative about love so strong it kills the object of its affection �" living cells. The app for that song, as well as several others, was designed by Scott Snibbe �" he also helped coordinate the efforts of the other designers, who hailed from all over the world. "Virus," he says, works a bit like a game, in which beautiful pink cells are attacked by spiky green viruses.

"You can try to save the cell," Snibbe says, "but if you succeed in saving the cell the song stops progressing. And meanwhile, the cells around are singing along: You see nuclei turn into lips that sing along with the song."

Bjork says her view of nature is hardly romantic, and that she took care to ensure that the project didn't become Disney-fied.

"Coming from Iceland ... nature is anything but cute," she says. "I could never really understand why, when people think of nature, they think of flower power and acoustic guitars. It's very creative, nature. But it's also very destructive."

Musical Education

Scott Snibbe says he and Bjork communicated regularly, sometimes exchanging hundreds of emails a day. They also worked with scientists to make the apps as scientifically accurate as they could. But, Snibbe says, the project is more about whetting people's appetites than providing a lesson plan.

"It gets you excited to learn more about it. If you associate viruses with a great song by Bjork and this emotional, strange, animated love story, then you might pay attention a little bit more in class," Snibbe says. "Or you might type it into Google and see a little bit about how it works."

Bjork says she wants to help people explore. Rather than schedule a traditional concert tour, with a day or two in each city, she plans residencies that will last for two months or more in 10 cities around the world. She'll play a couple nights a week and then spend time at a local museum, working with kids on music and science projects. Bjork says watching her 8-year-old daughter play with the Biophilia app of the solar system made her she realize its potential.

"She knew more about the solar system than I learned from five years of school �" that certain things are not meant to be in a book, you know? If ... it's more like a little game, then you understand it in 3D, like in space," Bjork says. "Music is like this: You cannot learn it from a book."

But Bjork says music is still central to Biophilia. People can buy the apps and play along, or they can just buy the CD, which she says will hold up on its own. Her multimedia experiment is attracting a lot of attention from people in the music industry, who hope it'll inspire a new way of making and selling albums to consumers, who seem to want to do more now than just listen.