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Mystery in the Ozone Layer

High above Earth, more than 20 miles above sea level, a diaphanous layer of ozone surrounds our planet, absorbing energetic UV rays from the sun.  It is, essentially, sunscreen for planet Earth. Without the ozone layer, we would be bathed in dangerous radiation on a daily basis, with side effects ranging from cataracts to cancer.

People were understandably alarmed, then, in the 1980s when scientists noticed that manmade chemicals in the atmosphere were destroying this layer. Governments quickly enacted an international treaty, called the Montreal Protocol, to ban ozone-destroying gases such as CFCs then found in aerosol cans and air conditioners.  On September 16, 1987, the first 24 nations signed the treaty; 173 more have signed on in the years since.

Fast forward 27 years.  Ozone-depleting chemicals have declined and the ozone hole appears to be on the mend. The United Nations has called the Montreal Protocol “the most successful treaty in UN history.” Yet, despite Montreal’s success, something is not … quite … right.

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A new ScienceCast video looks into the surprising abundance of carbon tetrachloride in the ozone layer.  Where is it coming from?

A new study by NASA researchers shows that a key ozone-depleting compound named carbon tetrachloride (CCl4) is surprisingly abundant in the ozone layer.

“We are not supposed to be seeing this at all,” says NASA atmospheric scientist Qing Liang.

Between 2007 and 2012, countries around the world reported zero emissions of CCl4, yet measurements by satellites, weather balloons, aircraft, and surface-based sensors tell a different story.  A study led by Liang shows worldwide emissions of CCl4 average 39 kilotons per year, approximately 30 percent of peak emissions prior to the international treaty going into effect.

In the 1980s, chlorofluorocarbons became well-known to the general public.  As the ozone hole widened, “CFC” became a household word.  Fewer people, however, have heard of CCl4, once used in applications such as dry cleaning and fire-extinguishers.

“Nevertheless,” says Liang, “CCl4 is a major ozone-depleting substance. It is the 3rd most important anthropogenic ozone-depleting compound behind CFC-11 and CFC-12.”

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Click to learn about the chemistry of ozone depletion from the US Environmental Protection Agency.Web link

Levels of CCl4 have been declining since the Montreal Protocol was signed, just not as rapidly as expected.  With zero emissions, abundances should have dropped by 4% per year.  Instead, the decline has been closer to 1% per year.

To investigate the discrepancy, Liang and colleagues took CCl4 data gathered by NOAA and NASA and plugged it into a NASA computer program, the 3-D GEOS Chemistry Climate Model.  This sophisticated program takes into account the way CCl4 is broken apart by solar radiation in the stratosphere as well as how the compound can be absorbed and degraded by contact with soil and ocean waters.  Model simulations pointed to an unidentified ongoing current source of CCl4.

“It is now apparent there are either unidentified industrial leakages, large emissions from contaminated sites, or unknown CCl4 sources,” says Liang.

Another possibility is that the chemistry of CCl4 might not be fully understood. Tellingly, the model showed that CCl4 is lingering in the atmosphere 40% longer than previously thought. “Is there something about the physical CCl4 loss process that we don’t understand?” she wonders.

It all adds up to a mystery in the ozone layer.

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Colorful Lunar Eclipse

On Wednesday morning, Oct. 8th, not long before sunrise, the bright full Moon over North America will turn a lovely shade of celestial red.  It’s a lunar eclipse—visible from all parts of the USA.

“It promises to be a stunning sight, even from the most light polluted cities,” says NASA’s longtime eclipse expert Fred Espenak. “I encourage everyone, especially families with curious children, to go out and enjoy the event.”

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A new ScienceCast video examines the red and turquoise colors sky watchers can expect to see during the Oct. 8, 2014, total lunar eclipse. Play it

From the east coast of North America, totality begins at 6:25 am EDT.  The Moon will be hanging low over the western horizon, probably swollen by the famous Moon illusion into a seemingly-giant red orb, briefly visible before daybreak. West-coast observers are even better positioned. The Moon will be high in the sky as totality slowly plays out between 3:25 am and 4:24 am PDT.

During a lunar eclipse, the Moon passes deep inside the shadow of our planet, a location that bathes the the face of the Moon in a coppery light.

A quick trip to the Moon explains the color: Imagine yourself standing on a dusty lunar plain looking up at the sky. Overhead hangs Earth, nightside down, completely hiding the sun behind it. The eclipse is underway.

You might expect Earth seen in this way to be utterly dark, but it’s not. The rim of the planet is on fire! As you scan your eye around Earth’s circumference, you’re seeing every sunrise and every sunset in the world, all of them, all at once. This incredible light beams into the heart of Earth’s shadow, filling it with a coppery glow and transforming the Moon into a great red orb.

However, red is not the only color.  Many observers of lunar eclipses also report seeing a band of turquoise.

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Click to see a worldwide eclipse visibility map

The source of the turquoise is ozone. Atmospheric scientist Richard Keen of the University of Colorado explains: “During a lunar eclipse, most of the light illuminating the moon passes through the stratosphere where it is reddened by scattering. However, light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer.” This can be seen, he says, as a soft blue fringe around the red core of Earth’s shadow.

To catch the turquoise on Oct. 8th, he advises, “look during the first and last minutes of totality. The turquoise rim is best seen in binoculars or a small telescope.”

The depth and hue of lunar eclipse colors depends a lot on the dustiness of the stratosphere.  When volcanoes erupt and chock the stratosphere with aerosols, lunar eclipses can turn such a deep red that the Moon looks almost black.  That’s not the case this time, however:

“Despite some recent eruptions that look spectacular from the ground, there have been no large injections of volcanic gases into the stratosphere,” says Keen. “In the absence of volcanic effects, I expect a rather normal reddish-orange lunar eclipse similar in appearance to last April’s eclipse.”

In other words, this is going to be good.

Espenak notes that “the total lunar eclipse of Oct. 8 is the second of four consecutive total lunar eclipses. Such a set of total eclipses is known as a tetrad.” The next eclipse in the tetrad is six months from now, in April 2015.

“Don’t wait,” he urges. Mark your calendar for October 8th, wake up early, and enjoy the show.


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2014 Arctic Sea Ice Minimum Sixth Lowest on Record

Arctic sea ice coverage continued its below-average trend this year as the ice declined to its annual minimum on Sept. 17, according to the NASA-supported National Snow and Ice Data Center (NSIDC) at the University of Colorado, Boulder.

“Arctic sea ice coverage in 2014 is the sixth lowest recorded since 1978,” said Walter Meier, a research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

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An animation of daily Arctic sea ice extent from March 21 to Sept. 17 – when the ice appeared to reach it’s minimum extent for the year. It’s the sixth lowest minimum sea ice extent in the satellite era. The data was provided by the Japan Aerospace Exploration Agency.

Over the 2014 summer, Arctic sea ice melted back from its maximum extent reached in March to a coverage area of 1.94 million square miles (5.02 million square kilometers), according to analysis from NASA and NSIDC scientists. This year’s minimum extent is similar to last year’s and below the 1981-2010 average of 2.40 million square miles (6.22 million square km).

“The summer started off relatively cool, and lacked the big storms or persistent winds that can break up ice and increase melting,” said Meier. Nevertheless, the season ended with below-average sea ice. “Even with a relatively cool year, the ice is so much thinner than it used to be. It is more susceptible to melting,” he explained.

This summer, the Northwest Passage above Canada and Alaska remained ice-bound. A finger of open water stretched north of Siberia in the Laptev Sea, reaching beyond 85 degrees north, which is the farthest north open ocean has reached since the late 1970s, according to Meier.

While summer sea ice has covered more of the Arctic in the last two years than in 2012’s record low summer, this is not an indication that the Arctic is returning to average conditions, Meier said. This year’s minimum extent remains in line with a downward trend; the Arctic Ocean is losing about 13 percent of its sea ice per decade.

To measure sea ice extent, scientists include areas that are at least 15 percent ice-covered. The NASA-developed computer analysis, which is one of several methods scientists use to calculate extent, is based on data from NASA’s Nimbus 7 satellite, which operated from 1978 to 1987, and the U.S. Department of Defense’s Defense Meteorological Satellite Program, which has provided information since 1987.

In addition to monitoring sea ice from space, NASA is conducting airborne field campaigns to track changes in Arctic sea ice and its impact on climate. Operation IceBridge flights have been measuring Arctic sea ice and ice sheets for the past several years during the spring. A new field experiment, the Arctic Radiation – IceBridge Sea and Ice Experiment (ARISE) started this month to explore the relationship between retreating sea ice and the Arctic climate.


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Hourly 5-minute walks ‘reverse arterial damage caused by sitting’

The harm to leg arteries caused by sitting for hours can be easily reversed with hourly 5-minute walks, according to new research published in Medicine & Science in Sports & Exercise, the official journal of the American College of Sports Medicine.
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The researchers found no decrease in arterial function among the participants who walked for 5 minutes each hour.

Sitting for prolonged periods is associated with risk factors for cardiovascular and metabolic disease, such as higher cholesterol levels and greater waist circumference. Because muscles are slackened when sitting, they do not contribute to pumping blood to the heart. This causes blood to pool in the legs, damaging the endothelial function of arteries and impairing blood vessels’ ability to expand.

In the new study, 11 healthy, non-obese men aged between 20 and 35 years took part in two randomized trials.

In the first trial, the participants were required to sit for 3 hours without moving their legs. How well their femoral artery – the large artery in the thigh – was functioning was measured using a blood pressure cuff and ultrasound technology. Readings were taken before the study commenced, and at the 1, 2 and 3-hour marks.

In the second experiment, the men again sat for 3 hours, but also walked on a treadmill set at a speed of 2 mph for 5 minutes at the 30-minute, 1.5-hour and 2.5-hour marks. Again, the researchers measured how well the femoral arteries of the participants were functioning.

The researchers found that, while sitting, the dilation and expansion of the participants’ arteries were impaired by up to 50% after just the first hour.

However, there was no decrease in arterial function among the participants who walked for 5 minutes each hour. The researchers think this is because the increase in muscle activity aided blood flow.

Americans sit for 8 hours a day, on average

“American adults sit for approximately 8 hours a day,” says study leader Saurabh Thosar, a postdoctoral researcher at Oregon Health & Science University. “The impairment in endothelial function is significant after just 1 hour of sitting. It is interesting to see that light physical activity can help in preventing this impairment.”

Thosar continues:

“There is plenty of epidemiological evidence linking sitting time to various chronic diseases and linking breaking sitting time to beneficial cardiovascular effects, but there is very little experimental evidence. We have shown that prolonged sitting impairs endothelial function, which is an early marker of cardiovascular disease, and that breaking sitting time prevents the decline in that function.”

Recently, Medical News Today reported on a study published in the British Journal of Sports Medicine, which suggested that reducing the amount of sitting time could protect DNA and even prolong lifespan.

The researchers behind that study found that reduced sitting time is linked to lengthening of telomeres – the protective “caps” at the end of chromosomes that prevent their genetic code from unraveling or clumping together.

Other studies in 2014 have suggested that standing – rather than sitting – during work meetings indirectly benefits work performance in organizations where knowledge-based working is important, and that walking boosts creative thinking.

Also, in June, researchers involved in the Behavioral Sleep Medicine Program at the Feinberg School of Medicine at Northwestern University in Chicago, IL, found that people who are late to bed spend more time sitting and are less motivated to maintain an exercise schedule.


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Study shows ‘mind-to-mind’ communication in humans

 In a study that for the first time establishes the feasibility of direct brain-to-brain communication, an international group of researchers has successfully shown it is possible to non-invasively transmit a thought from one person to another 5,000 miles away, without either of them having to speak or write.

Indeed, in a paper on the work published in PLOS ONE, the authors argue that what the study shows should probably be termed “mind-to-mind” transmission as opposed to “brain-to-brain,” because “both the origin and the destination of the communication involved the conscious activity of the subjects.”

In the brain-to-brain equivalent of “instant messaging,” the study shows how the international team of neuroscientists and robotics engineers used various “neurotechnologies” to send messages via the Internet between the intact scalps of two human subjects over 5,000 miles apart – one in India and the other in France.

The team included members from Beth Israel Deaconess Medical Center (BIDMC), a teaching affiliate of Harvard Medical School (HMC) in Boston, MA, Starlab Barcelona in Spain, and Axilum Robotics in Strasbourg, France.

Brain-to-brain over the Internet without talking or typing

Co-author Alvaro Pascual-Leone, Director of the Berenson-Allen Center for Noninvasive Brain Stimulation at BIDMC and HMC Professor of Neurology, explains how they wanted to discover if it was possible to send messages between two people by reading out the brain activity from one into the other, and to do it across a great distance, using existing communication pathways:

“One such pathway is, of course, the Internet, so our question became – could we develop an experiment that would bypass the talking or typing part of Internet and establish direct brain-to-brain communication between subjects located far away from each other in India and France?”

And they proved that the answer to their question was “Yes.”

The team chose to transmit thoughts from India to France using two brain technologies linked by a computer brain interface via the Internet: electroencephalogram (EEG) and robot-assisted and image-guided transcranial magnetic stimulation (TMS).

illustration of people with connected brains
The team believes the findings are an important step toward exploring whether it is possible to communicate from mind to mind without the use of language or gestures.

Previous studies have already shown that a person can have a conscious thought about moving an arm or a leg, and that thought can be conveyed via EEG-based brain-computer interaction to a computer that passes it to a robot that moves a limb or controls a wheelchair.

But this new study takes that a stage further by adding a second human brain to the other end of the communication system.

The researchers recruited four healthy volunteers – aged between 28 and 50 – to take part in a number of experiments. One was the sender – based in India, and the other three were receivers of the messages and had to understand them – they were based in France.

The EEG picked up the “thoughts” in the sender – the greeting “hola” (which means “hello” in Catalan or Spanish) or “ciao” (“hello” or “goodbye” in Italian) – which were then assigned to the brain-computer interface to send as a binary code by email from India to France. In France, a computer-brain interface translated the thoughts into signals that passed through the scalps of the receivers as non-invasive brain stimulations with the help of robotized TMS.

The receivers experienced the brain stimulations as “phosphenes” – flashes of light on the periphery of their vision. The flashes appeared in numerical sequences that the receivers could then decode into the messages.

Toward mind-to-mind communication without using language or gestures?

The team carried out similar experiments between Spain and France. The final results showed an error rate of only 15%, with 5% error rate on the sending side and 11% error rate on the receiving side.

Prof. Pascual-Leone says thanks to the advanced precision neuro-technologies, namely the wireless EEG at the sending end and the robotized TMS at the receiving end, they directly and non-invasively transmitted thoughts from one person to another, without them having to speak or write, and adds:

“This in itself is a remarkable step in human communication, but being able to do so across a distance of thousands of miles is a critically important proof-of-principle for the development of brain-to-brain communications.”

The team believes the findings are an important step toward exploring whether it is possible to communicate from mind to mind without the use of language or gestures.

Transcranial magnetic stimulation (TMS) is a relatively new method of pain-free stimulation of brain cells. In 2011, researchers described in two studies how they discovered the activity of distinct brain cell types changed with different TMS patterns.


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Scientists Remotely Activate Genetic Target To Slow Aging Process

The body loses its ability to regulate processes and prevent disease over time, which is why age is a risk factor for many debilitating conditions. However, this might not always be the case. A team of researchers have identified a gene that could be used to stave off senescence. Better yet, the team found a way to remotely activate the gene in a part of the body other than the one they wish to target. The research was led by David Walker of UCLA and the paper was published in Cell Reports.

AMP-activated protein kinase (AMPK) is an enzyme found in eukaryotic organisms and assists in regulating cellular energy levels. Low energy levels activate AMPK, which synthesizes ATP through fatty acid metabolism and increased glucose uptake.

Fruit flies that had the gene activated in their intestines lived 30% longer, increasing their lifespan from an average six weeks to eight weeks. This increase didn’t just prolong the flies’ life, but also the quality of it as well. Walker’s team found that the longer-lived fruit flies remained healthier than their control counterparts.

If similar effects could be seen in humans, that would be equivalent to changing an 80 year life expectancy to 104 years; plus the added bonus of those later years being healthier and less reliant on others.

“Instead of studying the diseases of aging—Parkinson’s disease, Alzheimer’s disease, cancer, stroke, cardiovascular disease, diabetes—one by one, we believe it may be possible to intervene in the aging process and delay the onset of many of these diseases,” commented Walker in a statement. “We are not there yet, and it could, of course, take many years, but that is our goal and we think it is realistic.

“The ultimate aim of our research is to promote healthy aging in people.”

The key to this technique is microautophagy, in which the cell disposes of old or damaged pieces. If this cell waste isn’t removed from the brain, it can potentially build up and cause diseases like Alzheimer’s and Parkinson’s. Clearing out the clutter also protects against other negative effects of aging in other parts of the body. While previous research has shown that AMPK activates autophagy, Walker’s team investigated whether this activity could be boosted.

Indeed, they discovered that when the AMPK gene is activated in the nervous system of fruit flies, autophagy increased in the gut. Likewise, AMPK activation in the intestines caused increased autophagy in the brain. As it is easier to target the intestines, this would allow scientists to remotely clear out waste products in the brain.

Fruit flies are an excellent first step in genetic experiments since they have homologues of 75% of the genes that cause human disease. Though the researchers studied over 100,000 fruit flies over the course of this research, the real test will come when using animals whose physiology is closer to humans. A study published in the April 10, 2013 issue of Neuronfound a connection between overproduction of AMPK and early signs of Alzheimer’s, so it remains to be seen how this approach will work in more complex organisms.

 Activating AMPK in the gut causes increased autophagy in the brain, and vice versa. Image credit: Matthew Ulgherait/UCLA


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Earth’s tectonic plates have doubled their speed

SO MUCH for slowing down as you age. Earth’s tectonic plates are moving faster now than at any point in the last 2 billion years, according to the latest study of plate movements. But the result is controversial, since previous work seemed to show the opposite.

Crust forming faster? <i>(Image: Alex Mustard/naturepl.com)</i>

If true, the result could be explained by another surprising recent discovery: the presence of more water within Earth’s mantle than in all of the oceans combined.

Plate tectonics is driven by the formation and destruction of oceanic crust. This crust forms where plates move apart, allowing hot, light magma to rise from the mantle below and solidify. Where plates are being pushed together, the crust can either rise up to form mountains or one plate is shoved under the other and is sucked back into the mantle.

The planet’s inner heat powers plate tectonics. That heat is ebbing away as Earth ages, and this was expected to slow plate motion. A study last year byMartin Van Kranendonk at the University of New South Wales in Sydney, Australia, and colleagues measured elements concentrated by tectonic action in 3200 rocks from around the world, and concluded that plate motion has been slowing for 1.2 billion years.

Now Kent Condie, a geochemist at the New Mexico Institute of Mining and Technology in Socorro and his colleagues have used a different approach and concluded that tectonic activity is increasing. They looked at how often new mountain belts form when tectonic plates collide with one another. They then combined these measurements with magnetic data from volcanic rocks to work out at which latitude the rocks formed and how quickly the continents had moved.

Both techniques showed plate motion has accelerated. The average rate of continental collisions, and the average speed with which the continents change latitude, has doubled over the last 2 billion years (Precambrian Research, doi.org/vbv).

“We expected to find that the average speed would be slowing down with time, but we didn’t get that. Both speeds were going up,” says Condie. “It was a surprise.”

Condie thinks the mantle’s huge store of water could explain the finding. When crust sinks back into the mantle, oceanic water gets sucked down too, and although most comes back to the surface in volcanic emissions, over the aeons the store of water in the mantle has grown vast.

Some of this water forms hydrous minerals that essentially make the mantle more runny, says Condie, speeding up the flow of rock. The effect is strong enough to overcome the stiffening of the mantle caused by the gradual cooling inside Earth, he says.

Peter Cawood at the University of St Andrews in the UK thinks the work is interesting and provocative. “The overall increase in the rate of plate motion with time seems real and believable,” he says, and could well be linked to changes in the mantle’s water content – although convincing sceptics that plates move faster now will be difficult without more data, he adds.

Van Kranendonk is not ready to change his mind. “Our paper documents a reduction in the rate and volume of crustal recycling for 1.2 billion years, supporting the idea that plate tectonics actually has been slowing down since that time,” he says.