Microbial Art

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Image: Wikimedia Commons

Biochemist Roger Tsien won the 2008 Nobel prize in chemistry for his contributions to knowledge of green fluorescent protein, a complex of amino acid residues that glow vividly when exposed to ultraviolet light.

Inspired, Nathan Shaner, a researcher in Tsien’s lab, painted this San Diego beach scene using an eight-color palette of bacterial colonies expressing fluorescent proteins.

Alexander Fleming was drawing “germ paintings” in the 1930s.

Skyward

When Gabe McCubbins’ daughter needed a project for her seventh grade science fair, they decided to mount a GoPro video camera in a bowling ball and fire it out of a cannon.

Launch starts at 1:50.

A One and a Two

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Image: Wikimedia Commons

In 2013, Georgia Institute of Technology mechanical engineer David Hu and his colleagues discovered a “law of urination”: All mammals weighing more than 1 kilogram empty their full bladders in about 21 seconds (standard deviation 13 seconds).

Last year Hu followed that up with a law of defecation: Despite a rectum length varying from 4 to 40 centimeters, mammals from cats to elephants defecate within a nearly constant duration of 12 ± 7 seconds. A layer of mucus helps feces slide through the large intestine; larger animals have more feces but also thicker layers of mucus, which aids their ejection.

From the journal Soft Matter, whose cover artist deserves some kind of award.

(David L. Hu et al., “Hydrodynamics of Defecation,” Soft Matter 13:29 [August 2017], 4960-4970.) (Thanks, Colin.)

Troxler’s Fading

https://commons.wikimedia.org/wiki/File:Troxler-Effekt.jpg

Stare at the cross from a short distance away without moving your eyes. After a few seconds, the colors will fade away.

The effect was discovered by Swiss physician Ignaz Paul Vital Troxler in 1804. The reasons for it aren’t clear — possibly neurons in the visual system adapt to unchanging stimuli and they drop out of our awareness.

Two by Two

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In poker, suppose you’re dealt a pair. Is the probability that your opponent also holds a pair higher, lower, or the same as it would be if you held nothing?

Click for Answer

Robinson Tiles

https://commons.wikimedia.org/wiki/File:Robinson_tiles.svg

Berkeley mathematician Raphael Robinson discovered this remarkable set of aperiodic tiles in 1978. The six shapes will neatly tile a plane, as shown below, and though the pattern cannot be regular, it reliably produces a hierarchical design: Each small orange square sits at the corner of a larger orange square, which sits at the corner of a still larger one, and so on ad infinitum. This is because subgroups of tiles form “supertiles” with similar properties — see here.

https://commons.wikimedia.org/wiki/File:Robinson_tiling.jpg

(Thanks, Jacob.)

Time and Talk

Speakers of the Kuuk Thaayorre language, spoken by the Thaayorre people in Queensland’s Pormpuraaw settlement, use absolute cardinal directions (north, south, east, west) rather than relative spatial terms (left, right), even at small scales. So, for example, they would say, “The cup is southeast of the plate” or “The boy standing to the south of Mary is my brother.”

In 2010, University of California psychologists Lera Boroditsky and Alice Gaby gave Kuuk Thaayorre speakers sets of cards depicting temporal progressions — a man aging, a crocodile growing, a banana being eaten — and asked them to arrange the shuffled cards on the ground to indicate the correct temporal order.

English speakers arrange the cards from left to right, Hebrew speakers from right to left. But the Kuuk Thaayorre arranged them from east to west, regardless of the direction the subjects themselves were facing.

Among other things, this means that the Kuuk Thaayorre must be constantly aware of their orientation in the world. “We never told anyone which direction they were facing,” Boroditsky wrote later. “The Kuuk Thaayorre knew that already and spontaneously used this spatial orientation to construct their representations of time.”

(Lera Boroditsky, “How Language Shapes Thought,” Scientific American 304:2 [February 2011], 62-65.)

The Big Picture

https://www.maxpixel.net/Space-Biosphere-Planet-Solar-System-Earth-1272884

Give a hundred people a picture of the earth, identify the North Pole for them, and a hundred will hold the photo with the North Pole toward their head and the South Pole toward their feet. Of course, what they are really doing, if they are standing up, is pointing the South Pole at the center of the earth and, if they are standing at the equator, pointing the North Pole at some spot in the sky, which, as the earth turns, traces a circle intersecting the plane of the ecliptic at 23 1/2 degrees. Now why people persist in this foolishness I don’t know. In my living room I have a small framed photograph showing a thin crescent against a black background. Even though the colors are wrong, people always say, ‘Oh, the moon!’; but it is the earth. The earth isn’t ever supposed to be a crescent, I suppose.

— Astronaut Michael Collins, Carrying the Fire, 1975