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Frequent Sighing Helps Keep You Alive

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Good news for hopeless romantics and the perpetually dismayed: All that sighing is good for you. In fact, you’d die without it. Scientists have now pinpointed the region in the brain that transforms normal breathing into a life-giving sigh. They published their findings this week in the journal Nature.  Let’s start with the mechanics. Physiologically speaking, sighing is a way of keeping your lungs inflated. “A sigh is a deep breath, but not a voluntary deep breath,” study co-author Jack Feldman said in a press release. “It starts out as a normal breath, but before you exhale, you take a second breath on top of it.” Whether you realize it or not, you do this about 12 times an hour, and even more than that when you’re stressed or anxious. And it’s a good thing you do. “If you don’t sigh every five minutes of so, the alveoli will slowly collapse, causing lung failure,” Feldman said. “That’s why patients in early iron lungs had such problems, because they never sighed.” The machines had not been programmed to give patients regular deep, lung-filling breaths. One group of researchers sifted through nearly 19,000 gene expression patterns in the active brains of mice, looking for the root of the sigh reflex. It was much smaller than they expected: just one little bundle of 200 cells in the brain stem, releasing one of two molecules called peptides. They shared their data with Feldman’s lab, and together the team found another set of 200 cells on the peptide receiving end.

A mouse's sigh clusters. Image credit: Stanford/Krasnow Lab

When the scientists prevented one peptide from reaching its goal, the rate of the mice’s sighing was cut in half. Blocking both peptides caused the mice to stop sighing altogether.  “Unlike a pacemaker that regulates only how fast we breathe, the brain’s breathing center also controls the type of breath we take,” co-author Mark Krasnow noted in the press release. “It’s made up of small numbers of different kinds of neurons. Each functions like a button that turns on a different type of breath. One button programs regular breaths, another sighs, and the others could be for yawns, sniffs, coughs, and maybe even laughs and cries.” It’s highly unusual for such small clusters of neurons to have so much power, Feldman said. “Sighing appears to be regulated by the fewest number of neurons we have seen linked to a fundamental human behavior.”  The team’s findings may someday lead to treatment for people with diseases that limit their breathing. “These molecular pathways are critical regulators of sighing, and define the core of a sigh-control circuit,” Krasnow said. “It may now be possible to find drugs that target these pathways to control sighing.” 

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Why a Howling Wind Sounds So Spooky, According to Science
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Halloween is swiftly approaching, meaning you'll likely soon hear creepy soundtracks—replete with screams, clanking chains, and howling winds—blaring from haunted houses and home displays. While the sound of human suffering is frightful for obvious reasons, what is it, exactly, about a brisk fall gust that sends shivers up our spines? In horror movie scenes and ghost stories, these spooky gales are always presented as blowing through dead trees. Do bare branches actually make the natural wailing noises louder, or is this detail added simply for atmospheric purposes?

As the SciShow's Hank Green explains in the video below, wind howls because it curves around obstacles like trees or buildings. When fast-moving air goes around, say, a tree, it splits up as it whips past, before coming back together on the other side. Due to factors such as natural randomness, air speed, and the tree's surface, one side's wind is going to be slightly stronger when the two currents rejoin, pushing the other side's gust out of the way. The two continue to interact back-and-forth in what could be likened to an invisible wrestling match, as high-pressure airwaves and whirlpools mix together and vibrate the air. If the wind is fast enough, this phenomenon will produce the eerie noise we've all come to recognize in horror films.

Leafy trees "will absorb some of the vibrations in the air and dull the sound, but without leaves—like if it's the middle of the winter or the entire forest is dead—the howling will travel a lot farther," Green explains. That's why a dead forest on a windy night sounds so much like the undead.

Learn more by watching SciShow's video below.

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SpaceX's Landing Blooper Reel Shows That Even Rocket Scientists Make Mistakes
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SpaceX's Falcon 9 rocket launches.
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On March 30, 2017, SpaceX did something no space program had done before: They relaunched an orbital class rocket from Earth that had successfully achieved lift-off just a year earlier. It wasn't the first time Elon Musk's company broke new ground: In December 2015, it nailed the landing on a reusable rocket—the first time that had been done—and five months later landed a rocket on a droneship in the middle of the ocean, which was also unprecedented. These feats marked significant moments in the history of space travel, but they were just a few of the steps in the long, messy journey to achieve them. In SpaceX's new blooper reel, spotted by Ars Technica, you can see just some of the many failures the company has had along the way.

The video demonstrates that failure is an important part of the scientific process. Of course when the science you're working in deals with launching and landing rockets, failure can be a lot more dramatic than it is in a lab. SpaceX has filmed their rockets blowing up in the air, disintegrating in the ocean, and smashing against landing pads, often because of something small like a radar glitch or lack of propellant.

While explosions—or "rapid unscheduled disassemblies," as the video calls them—are never ideal, some are preferable to others. The Falcon 9 explosion that shook buildings for miles last year, for instance, ended up destroying the $200 million Facebook satellite onboard. But even costly hiccups such as that one are important to future successes. As Musk once said, "If things are not failing, you are not innovating enough."

You can watch the fiery compilation below.

[h/t Ars Technica]

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