November 6, 2023: Hi all. I'm covering for Andrea Gawrylewski this week and next. For your Monday reading pleasure: dancing fish, a breast scanner that fits in a bra, and better ways to count votes. —Robin Lloyd, Contributing Editor | | | Rather than using echolocation or eyesight alone to navigate murky rivers, the elephantnose fish relies on electrolocation…with a twist. A specialized organ in the fish's tail emits a weak electric field that radiates outward from its body. Tiny receptors on its skin, including electroreceptors in a fleshy protrusion from its chin called a schnauzenorgan (no joke), detect distortions to the field caused by objects or creatures nearby. These distortions yield a two-dimensional representation of the object being detected like a shadow cast on the goofy-looking fish's skin.
The twist: A little dance allows the elephantnose fish to use the 2-D map to perceive a 3-D world, according to a new study published in Animal Behaviour. By wiggling around, the fish perceives objects from slightly different angles; stacked together, the various electric images are enough for it to distinguish among 3-D objects.
What the experts say: It's no wonder the elephantnose fish has the highest brain-to-body weight ratio of any vertebrate, including humans, researchers say. "It's just so complex, what they do, that we can't really model it with our greatest computers," says Stefan Mucha, a postdoc studying fish at the Humboldt University of Berlin. "But it's just a small fish!" | | | A Peters's elephantnose fish (Gnathonemus petersii). Credit: Leonid Serebrennikov/Alamy Stock Photo | | | A new portable breast cancer scanner that fits in a bra is designed to detect aggressive breast cancer. Canan Dagdeviren, a materials engineer at the Massachusetts Institute of Technology, and her colleagues miniaturized a scanner using a new type of material that better penetrates deep tissue than conventional ultrasound scanning machines. And it requires less power. The wearable scanner could be used at home to detect breast tumors earlier.
Why this matters: Women older than 50 in the U.S. are advised to get mammograms every two years, but the most aggressive tumors often arise and are diagnosed between screenings. More frequent screening is the key for survival. Dagdeviren says that "with a very humble calculation, we found that this has the potential to save 12 million lives per year globally."
What's next: Clinical trials are underway in a bid for approval from the Food and Drug Administration. | | | • Earth reacts to greenhouse gases more strongly than we thought, according to a new paper by climate scientist James Hansen and colleagues. | 11 min read. | 11 min read | | | • As voters nationwide head to the polls, it is worth thinking about how we count votes. A better method than plurality (the most first-choice wins), writes Jack Murtagh, is called instant runoff. Most ranked choice voting in the U.S.—which is used across two states—relies on this approach. If no candidate receives more than half of the first-choice votes, then the candidate with the fewest first-choice votes is removed from consideration and their votes get reallocated according to voters' next choices. The process of removing the candidate with fewest first-choice votes repeats until one candidate has a majority. Instant runoff, however, has drawbacks of its own. In fact, a theorem derived by Nobel Prize–winning economist Kenneth Arrow suggests that no ranked choice voting scheme is perfect. But ranked choice voting still does a better job at capturing the will of the electorate than plurality voting. We need to pick and choose which properties we want in our ranking scheme and acknowledge that we can't have it all, Murtagh writes. | 9 min read | | | The elephantnose fish discovery described above illustrates the fun of "fish stories." Here are two more good ones: A tiny reef fish called the bluestreak cleaner wrasse can recognize itself in a mirror and in photos. Perhaps you prefer aquatic and marine stories involving humans (besides, we all have an inner fish). If so, check out this man who recently set a world record in solving a Rubik's Cube underwater. Or watch the "Nyad" trailer and movie, about athlete Diana Nyad, who at the age of 60 committed to achieving her dream of an open ocean swim from Cuba to Key West. | —Robin Lloyd, Contributing Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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