Archive for the ‘science’ Category

Ahh, summer—ramlibacter season

November 14th, 2018
Image of a tractor sending dust into the air while plowing a field.

Enlarge / Even mundane activities can allow microbes to catch a ride on the wind. (credit: Christopher Griner)

Your gut isn’t the only place that harbors a community of microbes. There are also microbiomes coating your skin and most household, industrial, and commercial surfaces. There's even a community hanging out in the lower atmosphere. Scientists in Spain have monitored this airborne microbiome by taking rain and snow samples every two weeks for seven years at a site in the central Pyrenees. The samples were then run through a DNA sequencer to reveal the airborne microbiome. They found that the bacteria, archaea, protists, and fungi all varied predictably by season.

In the wintertime, microbes frequently had marine origins, coming primarily from the Atlantic, although these were mixed in with bugs from forest and other terrestrial sources. Overall, the winter atmospheric microbiome was the most diverse, and that diversity included the highest levels of pathogens in any season.

In the summer the microbiome was more regional, coming from the Mediterranean as well as fresh water, cropland, and cities. There was more pollution in the summer; the scientists monitored atmospheric levels of chemicals, including nitrates and sulphates, in addition to microbes. One of the most abundant and recurring taxa over the seven summers was Ramlibacter, related to a bacterium first isolated in 2011 from meteorite fragments buried in the sands near Tatouine, in Tunisia. It is specifically adapted to live in hot, dry, desert climes, so the researchers suggested that it could be used as a forensic signature for “summertime in Europe—African dust in the air”.

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Posted in atmosphere, environmental sciences, microbiome, science | Comments (0)

Galaxy mergers hide ravenous supermassive black holes

November 14th, 2018
Image of two galaxies merging.

Enlarge / When galaxies collide. (credit: NASA, ESA, the Hubble Heritage Team)

Black holes are… um, black. The point of a black hole is that the force of gravity is strong enough to prevent light from escaping its grasp. But the matter that is being sucked into a black hole is not at all happy about its fate. The matter gets hot and bothered and starts to glow very brightly before it reaches the black hole. This produces what are called luminous accreting black holes.

Most black holes are proud of themselves, sucking down matter right before our very eyes. But others are shy and seem to hide their antisocial behavior, raising questions about whether they were actually there. It turns out that these murderous monsters are hiding behind the gas clouds created by galaxy collisions. It took a serious amount of detective work to penetrate the fog.

Introducing the eyewitnesses

Astronomers have long recognized that not everything in the Universe happens slowly. Sure, our Sun will be stable for billions of years, but when things start to go wrong, they go downhill quickly (use your remaining eight minutes wisely). Likewise, when something big gets sucked into a black hole, it sends a last desperate SOS in the form of a bright X-ray flash.

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Posted in black holes, galaxy mergers, science, supermassive black holes | Comments (0)

Cave acoustics can help sculpt more realistic sounds in digital space

November 14th, 2018
Slim pickings: A search for “cave” in Altiverb sampling software shows Howe’s Cavern in NY and two locations in Malta, in addition to several man-made structures.

Enlarge / Slim pickings: A search for “cave” in Altiverb sampling software shows Howe’s Cavern in NY and two locations in Malta, in addition to several man-made structures. (credit: Yuri Lysoivanov)

Sound is very much an ephemeral phenomenon. So when acoustician Yuri Lysoivanov wanted to capture the unique acoustics of natural caves, he lugged all his recording equipment to Mammoth Cave in Kentucky, the better to analyze the reverberations and resonances. He described this experience at a meeting of the Acoustical Society of America in Victoria, Canada, earlier this month.

Reverberation is a critical design element, especially for performance spaces. It's not the same as an echo, which is what happens when a sound repeats. Reverb is what happens indoors when sound can't travel sufficient distance to produce those echoing delays. Instead, you get a continuous ring that gradually "decays" (fades).

American audio engineer Bill Putnam was the first person to use "artificial reverb" for commercial recording in the late 1940s with the Harmonicats' "Peg o' My Heart"—achieved by placing a microphone and loudspeaker in the recording studio's bathroom. (Bathroom and subway tiles have excellent reverberation, which is why buskers have their favorite spots in New York City's subway stations.) Today, one of the most popular digital techniques is called convolution reverb, which uses recordings of the acoustics of real spaces to produce highly realistic simulations of those spaces.

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Posted in acoustics, Altiverb, artificial reverb, audio engineering, geology, reverberation, science, signal processing, sound design, Tech | Comments (0)

This Chemical Is So Hot It Destroys Nerve Fibers—in a Good Way

November 14th, 2018
Resiniferatoxin is 10,000 times hotter than the hottest pepper, and has features that make it promising as a painkiller of last resort.

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Memristors built with 2-nanometer-thick parts

November 14th, 2018
Image of the crossbar array.

When two blocks are set down on top of each other, they're oriented so that they have nine intersections. (credit: Pi et al.)

Phase-change memory seems to offer the best of both worlds: the speed of current RAM with the permanence of a hard disk. While current implementations are too expensive for widespread use, researchers have been doing interesting things with test hardware. Its distinct properties have allowed people to perform calculations and train neural networks, all in memory. So finding out how to make phase-change memory more efficient could open some new approaches to computing.

This week, a collaboration between scientists at the University of Massachusetts, Amherst and Brookhaven National Lab is publishing a paper describing how it made a tiny set of memristors that acts similarly to phase-change memory. The features of the memory are only two nanometers across, and they can be separated by as little as 12nm—below the cutting edge of processor manufacturing. The down sides? So far, the team has only made nine bits at a time, and they're made using platinum.

On the grid

Key to this new work are tiny sheets of platinum only two nanometers thick—that's just over 11 atoms of the element. While platinum is rather pricey, the thin sheets provide extremely low resistance. The researchers measured each sheet at about 10,000 times less than the expected resistance of a similar-thickness carbon nanotube. And the authors say they can manufacture the sheets in the appropriate dimensions with a 100 percent efficiency.

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Posted in materials science, memory, Memristor, science | Comments (0)

What is going on with California’s horrific fires?

November 13th, 2018
Wildfire smoke blows westward on November 9.

Enlarge / Wildfire smoke blows westward on November 9. (credit: NASA)

Late last year, California experienced terrible—and in the case of the October Tubbs Fire, record-setting—wildfires. The fires were especially intense due to an unusually late start to the rainy season, which left vegetation dry as seasonal mountain winds kicked up like bellows in a forge.

This year, the situation has repeated. The Camp Fire in Northern California not only broke last year’s all-time record for structures burned, it also broke a much older record for the deadliest wildfire in the state’s history. And in Southern California, the Hill and Woolsey Fires have burned through homes on the north side of Los Angeles.

So what is going on with these extreme fires? Are they just chance or part of a trend? President Trump, via his Twitter account, has repeatedly blamed California for its fires and claimed that environmental policies for water use or forestry are somehow responsible. But these claims make no sense to anyone working in the state—or anyone who knows that forest fires aren’t put out by hose-carrying fire engines. In reality, many factors contribute to the current situation. And climate change is one of them.

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Posted in California, climate change, science, wildfires | Comments (0)

Climate Change: The Complete WIRED Guide

November 13th, 2018
The world is getting warmer, the weather is getting worse. Here's everything you need to know about what humans can do to stop wrecking the planet.

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Thermal power plants use a lot of water, but that’s slowly changing

November 13th, 2018
nuclear cooling towers

Enlarge / A view of the decommissioned Duke Energy Crystal River Nuclear Power Plant. (credit: Photo by: Jeffrey Greenberg/UIG via Getty Images)

It may come as a surprise that as of 2015, most of the water taken out of US ground- and surface-water sources was withdrawn by the electricity sector. Irrigation is a close second, and public supply is a distant third.

In 2015, thermal power generation—anything that burns fuel to create gas or steam that pushes a turbine—used 133 billion gallons of water per day. That water is mostly for cooling the equipment, but some of it is also used for emissions reduction and other processes essential to operating a power plant.

Those gallons are mostly freshwater, but some near-coast power generators do use saline or brackish water to operate. Much of the water is returned to the ecosystem, but some of it is also lost in evaporation. The water that is returned can often be thermally polluted, that is, it's warmer than what's ideal for the local ecosystem.

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Posted in Energy, Policy, science, thermal power, water | Comments (0)

Russian space leader suggests engineers test spacecraft Stalin’s way

November 13th, 2018
Dmitry Rogozin, head of Roscosmos, meets with company leaders at RSC Energia.

Enlarge / Dmitry Rogozin, head of Roscosmos, meets with company leaders at RSC Energia. (credit: RSC Energia/YouTube)

During a meeting this weekend at RSC Energia, the prime contractor for Russia's crewed spaceflight program, the discussion turned toward development of the Federation spacecraft. This is the oft-delayed program to develop a new generation of crewed spacecraft for the Russian space industry.

Dmitry Rogozin, the leader of Russia's space program, Roscosmos, was apparently not pleased with ongoing delays to the program. First initiated more than a decade ago, the Federation spacecraft now is unlikely to fly humans before 2023.

Rogozin made the following comments after one of the Federation engineers suggested that, perhaps, time could be saved in the spacecraft's development by reducing the number of tests of its emergency escape system.

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See How the Buoyancy Force Works in Water or Air

November 13th, 2018
The buoyancy force gives you the boost that helps you float and do cool maneuvers in water. This experiment lets you see it in action.

Posted in science, Science / Dot Physics | Comments (0)