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Tue, 26 Sep 2017
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Cloud Precipitation

Monster storms like Irma start off the coast of the Cape Verde islands, say researchers

Just weeks after Hurricane Harvey caused destruction in Texas, Irma has made landfall in Florida - and there are still almost 12 weeks left of Atlantic hurricane season. It raises the question - where are all of these storms coming from?

Research has shown that most of the monster storms that hit the US and Canada start out as a distinct weather pattern in the atmosphere over western Africa, specifically a spot off the coast of the African Cape Verde islands.

In fact, a 2015 study published in Geophysical Research Letters showed that by closely watching these tropical disturbances off the coast of western Africa, researchers could better predict which of them would turn into serious hurricanes a few weeks later.

Solar Flares

Sun unleashes major X8.2 solar flare, second strongest of the cycle & 4th X-class in a week

© spaceweather live.com
Sunspot region 2673 departs in style! The region is now behind the western limb but it still managed to produce it's fourth X-class solar flare: it erupted with an X8.28 (R3-strong) solar flare that peaked at 16:06 UTC.
This is the second strongest solar flare of solar cycle 24. Sunspot region 2673 was also responsible for the strongest solar flare of this solar cycle: X9.3 on 6 September! What an amazing sunspot region! You shall be missed!

With the X8.2 solar flare, a huge and very fast Coronal Mass Ejection was launched into space, it was seen by the STEREO A coronograph instrument.

Comment: Related articles from the past week:


US forecast models have been quite awful compared to European ones during Hurricane Irma

NOAA's best weather model seems to be getting worse with hurricanes, not better.

We have written a fair amount at Ars recently about the superiority of the European forecast model, suggesting to readers that they focus on the ensemble runs of this system to get a good handle on track forecasts for Hurricane Irma. Then we checked out some of the preliminary data on model performance during this major hurricane, and it was truly eye-opening.

Brian Tang, an atmospheric scientist at the University of Albany, tabulates data on "mean absolute error" for the location of a storm's center at a given time and where it was forecast to be at that time. Hurricane Irma has been a thing for about a week now, so we have started to get a decent sample size-at least 10 model runs-to assess performance.


Bacterial biofilms use bursts of electricity to communicate

© Olena Shmahalo/ Quanta Magazine
With electrical signals, cells can organize themselves into complex societies and negotiate with other colonies.
Bacteria have an unfortunate - and inaccurate - public image as isolated cells twiddling about on microscope slides. The more that scientists learn about bacteria, however, the more they see that this hermitlike reputation is deeply misleading, like trying to understand human behavior without referring to cities, laws or speech. "People were treating bacteria as ... solitary organisms that live by themselves," said Gürol Süel, a biophysicist at the University of California, San Diego. "In fact, most bacteria in nature appear to reside in very dense communities."

The preferred form of community for bacteria seems to be the biofilm. On teeth, on pipes, on rocks and in the ocean, microbes glom together by the billions and build sticky organic superstructures around themselves. In these films, bacteria can divide labor: Exterior cells may fend off threats, while interior cells produce food. And like humans, who have succeeded in large part by cooperating with each other, bacteria thrive in communities. Antibiotics that easily dispatch free-swimming cells often prove useless against the same types of cells when they've hunkered down in a film.

As in all communities, cohabiting bacteria need ways to exchange messages. Biologists have known for decades that bacteria can use chemical cues to coordinate their behavior. The best-known example, elucidated by Bonnie Bassler of Princeton University and others, is quorum sensing, a process by which bacteria extrude signaling molecules until a high enough concentration triggers cells to form a biofilm or initiate some other collective behavior.


NASA: The sun emits its sixth solar flare in just five days

The sun has emitted a sixth solar flare in just five days, the US National Aeronautics and Space Administration (NASA) said Friday.

"The sun emitted one mid-level solar flare on Sept. 8, 2017. The flare peaked at 3:49 a.m. EDT. This is the sixth sizable flare from the same active region since Sept. 4," the space agency said.

The flare was classified as an M-class one, measuring a tenth the size of the most intense flares, the X-class flares.



New research reveals a way to detoxify dirt - infrared lasers

© Colin/Flickr
To feed a growing population, our global food system relies on sufficient farmland. But over the past 40 years, one-third of arable land has been lost to erosion or sullied by pollution.

Man-made chemicals and fertilizers used to improve crop yields can persist in soil for years, making it less fertile over time. Antibiotics in animal manure seep out and also cause degradation. Oil spills and environmental disasters can impact large parcels of land. And all this is compounded by the sluggish pace at which new topsoil is formed-about 2.5 centimeters every 500 years.


Sine-wave speech: People who hear voices in their head can also pick up on hidden speech

© Depositphotos
Why some people hear voices where none is present has long been a psychological puzzle.
Serial killer David Berkowitz, also known as the "Son of Sam," famously claimed that he heard voices in the form of a dog telling him to commit murder. But hearing voices isn't necessarily a sign of psychosis. In fact, according to the authors of a recent study published in the journal Brain, enhanced attention-related nerual pathways might cause these illusory sounds. People hear them because their brains may be especially primed to pick up speech.


Gaydar: Stanford U. creates computer algorithm that can distinguish straight from gay

© Alamy
An illustrated depiction of facial analysis technology similar to that used in the experiment.
Artificial intelligence can accurately guess whether people are gay or straight based on photos of their faces, according to new research that suggests machines can have significantly better "gaydar" than humans.

The study from Stanford University - which found that a computer algorithm could correctly distinguish between gay and straight men 81% of the time, and 74% for women - has raised questions about the biological origins of sexual orientation, the ethics of facial-detection technology, and the potential for this kind of software to violate people's privacy or be abused for anti-LGBT purposes.

The machine intelligence tested in the research, which was published in the Journal of Personality and Social Psychology and first reported in the Economist, was based on a sample of more than 35,000 facial images that men and women publicly posted on a US dating website. The researchers, Michal Kosinski and Yilun Wang, extracted features from the images using "deep neural networks", meaning a sophisticated mathematical system that learns to analyze visuals based on a large dataset.

The research found that gay men and women tended to have "gender-atypical" features, expressions and "grooming styles", essentially meaning gay men appeared more feminine and vice versa. The data also identified certain trends, including that gay men had narrower jaws, longer noses and larger foreheads than straight men, and that gay women had larger jaws and smaller foreheads compared to straight women.

2 + 2 = 4

Professor Paul McKeigue on Khan Sheikhoun "chemical attack": How to weigh a mountain of evidence

© Tim Hayward
In this first of a two part special guest blog, my colleague Paul McKeigue will explain how the formal logic of probability theory can be used to evaluate the evidence for alternative explanations of an event like the Khan Sheikhoun chemical incident in April this year. As an epidemiologist and genetic statistician, Paul is expert in this approach.

Paul picks up on the recent debate between George Monbiot and myself (here and here) observing how we were somewhat at cross-purposes. George was insisting that I offer a competing explanation to the 'Assad did it' story, but I declined to speculate, having no independent way of knowing. Because George believed a "mountain" of evidence supported his belief, he found it vexing that I should question it without venturing a specific alternative explanation.

Comment: Air Strike in Syria: "We got a f***in' problem!"

In the days after part 2 of McKeigue's piece was published, the UN concluded that Syria was responsible for the Khan Sheikhoun attack: A read-through of McKeigue's analysis above should disabuse anyone of the notion that the UN report has a shred of objectivity about it.

Cloud Lightning

Hurricanes may trigger earthquakes

© Dmme.virginia.gov
Damage from the 2011 earthquake in Louisa County, Virginia.
In August 2011, the Virginia earthquake shook the east coast. Days later, Hurricane Irene may have caused more earthquakes

On August 23, 2011 a rare magnitude 5.8 earthquake hit Virginia. The shaking cracked the Washington Monument, toppled part of the National Cathedral and shook around a third of the U.S. population. Later that week, Hurricane Irene moved into the region, wiping out power, downing trees and, according to new research presented at the meeting of Seismological Society of America, says Nature, triggering more small earthquakes in the recently ruptured fault.

The rate of aftershocks usually decreases with time, says study leader Zhigang Peng, a seismologist at the Georgia Institute of Technology in Atlanta. But instead of declining in a normal pattern, the rate of aftershocks following the 23 August, 2012 , earthquake near Mineral, Virginia, increased sharply as Irene passed by.

Comment: The scientists suggest that hurricanes might relieve stress on faults, producing temblors.
Hurricane Irene, a powerful storm that ran north along the US East Coast four days after a magnitude-5.8 earthquake rattled Virginia in 2011, may have triggered some of that earthquake's aftershocks, scientists reported today at the annual meeting of the Seismological Society of America in Salt Lake City, Utah.

The rate of aftershocks usually decreases with time, says study leader Zhigang Peng, a seismologist at the Georgia Institute of Technology (Georgia Tech) in Atlanta. But instead of declining in a normal pattern, the rate of aftershocks following the 23 August 2011, earthquake near Mineral, Virginia, increased sharply as Irene passed by.

Peng and Xiaofeng Meng, a graduate student at Georgia Tech, then compared the aftershocks' timing to atmospheric-pressure readings in the earthquake zone, testing their hypothesis that a decrease in pressure caused by the storm's travel up the East Coast might have reduced forces on the fault enough to allow it to slip. That effect would be particularly strong for a thrust fault such as the one involved in the Virginia earthquake, Meng says. In that type of fault, one block of crust slides over another as the two blocks are pushed together.


The researchers are not the first to examine a potential link between hurricanes and seismic activity. Shimon Wdowinski, a seismologist at the University of Miami, Florida, says that he has found a strong correlation between extremely wet tropical cyclones striking Taiwan and big earthquakes that occur up to three years later. He thinks that the erosion of landslide debris in such a storm's aftermath triggers a change in fault loading, eventually producing an earthquake.