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May 7, 2019

What's behind the magical camouflage of squid?

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Five movies here are worth 10,000 multisyllable words.

From the New York Times:

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Squid Share a Colorful Trick With Peacocks

Squid are chameleons of the ocean, shifting effortlessly from hue to hue as they cross sand, coral, and grass. Scientists have long studied the peculiar structures in their skin that interact with light, trying to understand how the animals change color so swiftly and with such precision.

Now, a paper published last month in Nature Communications suggests that their chromatophores, previously thought to be mainly pockets of pigment embedded in their skin, are also equipped with tiny reflectors made of proteins. These reflectors aid the squid to produce such a wide array of colors, including iridescent greens and blues, within a second of passing in front of a new background. The research reveals that by using tricks found in other parts of the animal kingdom — like shimmering butterflies and peacocks — squid are able to combine multiple approaches to produce their vivid camouflage.

The researchers studied Doryteuthis pealeii, or the longfin squid, which is found in the North Atlantic Ocean.

Its chromatophores contain individual sacs of yellow, red, or brown pigment. Each one is also ringed with small muscles that allow the animal to clench shut or open wide each chromatophore. That means that in front of brown sea grass, for example, red and yellow chromatophores might cinch closed, allowing the brown pigments to show.

But what is the source of all those vivid blues and greens that squid are known to display? Researchers had long imagined that the layer below the chromatophores in the squid's skin might be responsible for those pyrotechnic shimmers. That underlayer is essentially an enormous reflector, made of cells that make a protein called reflectin.

However, that layer responds to changes too slowly to be the sole source of those colors, said Leila Deravi, a professor of chemistry at Northeastern University and an author of the new paper.

In search of answers, she and her collaborators at the Marine Biological Laboratory in Woods Hole, Massachusetts and elsewhere put squid skin under the microscope and saw something reflective on the surface of the chromatophores. As they moved a beam of light to shine at different angles off the skin, the round blobs of yellow, red, and brown pigment lit up like Christmas trees.

"We saw a really bright, metallic-y kind of color associated with the chromatophores," said Dr. Deravi. "And at different angles we could see blue-greens come out, we could see just the whole spectrum of color emerge."

Analyzing the proteins that the chromatophore cells were making, the team realized that reflectin was among them, and they confirmed with further lab work that it was distributed around the surface of the chromatophores.

Light strikes arrays of reflectin, bounces around, and refracts out, producing colors. The same kind of interaction, called structural color, produces the blue of a morpho butterfly's wings, a peacock's tail father, or a blue human eye.

Pigments, by contrast, like the one behind brown eyes, are small molecules that simply absorb some colors of light and release others. These are fundamentally different ways of making color. But squid have the benefit of both.

The squid control the movement of the reflectin that is on the outside of the chromatophores with the same movements that control the opening and closing of the structure's mouth, manipulating both kinds of color simultaneously. With this intimate connection between the two, "these cephalopods have evolved a way to help them become one of the fastest camouflaging species on the planet," Dr. Deravi said.

The shimmering, shifting surface of the squid's skin may someday provide insights for new materials that use the same tricks. But how exactly the squid matches its perception of its environment to its appearance using the precise manipulation of thousands of structures all over its skin is still a subject of much research.

"We were always continuously surprised by these animals. As soon as you think you kind of understand how they work, you find something else," Dr. Deravi said.

May 7, 2019 at 04:01 PM | Permalink | Comments (0)

Lake Baikal contains more water than all the Great Lakes combined

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How can this be?

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From Geology.com:

Lake Baikal is the world's largest freshwater lake in terms of volume. It contains about 5,521 cubic miles of water (23,013 cubic kilometers), or approximately 20% of Earth's fresh surface water. This is a volume of water approximately equivalent to all five of the North American Great Lakes combined. 

May 7, 2019 at 02:01 PM | Permalink | Comments (0)

The Palm — Odilon Redon

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"I have often, as an exercise and as a sustenance, painted before an object down to the smallest accidents of its visual appearance; but the day left me sad and with an unsatiated thirst. The next day I let the other source run, that of imagination, through the recollection of the forms and I was then reassured and appeased."—Odilon Redon

Above, a detail from the 1899 painting (oil on cardboard), pictured in its entirety below.

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In the collection of the Kröller-Muller Museum, Otterlo, Netherlands.

May 7, 2019 at 12:01 PM | Permalink | Comments (0)

Speech synthesis using a headset scanning the brain

From Nature:

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Technology that translates neural activity into speech would be transformative for people who are unable to communicate as a result of neurological impairments.

Decoding speech from neural activity is challenging because speaking requires very precise and rapid multi-dimensional control of vocal tract articulators.

Here we designed a neural decoder that explicitly leverages kinematic and sound representations encoded in human cortical activity to synthesize audible speech.

Recurrent neural networks first decoded directly recorded cortical activity into representations of articulatory movement, and then transformed these representations into speech acoustics.

In closed vocabulary tests, listeners could readily identify and transcribe speech synthesized from cortical activity.

Intermediate articulatory dynamics enhanced performance even with limited data.

Decoded articulatory representations were highly conserved across speakers, enabling a component of the decoder to be transferable across participants.

Furthermore, the decoder could synthesize speech when a participant silently mimed sentences.

These findings advance the clinical viability of using speech neuroprosthetic technology to restore spoken communication.

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Guardian science correspondent Hannah Devlin's story about the Nature report is useful and informative.

Wrote Ben Evans: "In about 20 years you'll probably be able to buy this."

That long?

May 7, 2019 at 10:01 AM | Permalink | Comments (1)

Ninben Tokusen Luxury Katsuobushi (dried, fermented, and smoked bonito)

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From the website:

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If you love to cook Japanese cuisine, this Ninben Tokusen Luxury Katsuobushi is the best way to experience the taste of dried, fermented, and smoked bonito.

It's the perfect gift for that aspiring washoku chef!

You might know katsuobushi as the shaved bonito flakes sold in stores, but this high-grade fish comes unshaved so you can prepare the flakes fresh at home.

Katsuobushi is a key ingredient to making authentic Japanese broth.

The broth can be used in so many Japanese dishes and if you use freshly shaved katsuobushi, you get that professional taste, far superior to pre-prepared bonito or dashi powder.

This Ninben Katsuobushi is truly traditional: it has gone through many processes to reach this level of perfection.

Ninben has been in business since 1699, honing its skills over 320 years.

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Features and Details:

• Best-by-date: 2 years after date of manufacture

• Instructions: Japanese

• Unshaved (not flakes)

• Gift box

• 9 oz.

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$45 (katsuobushi shaving instrument not included).

May 7, 2019 at 08:01 AM | Permalink | Comments (0)

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