Ice feature on Saturn's giant moon, TItan

This figure shows 3 orientations of Titan's globe. Mapped in blue is the icy corridor.

Rain, seas and a surface of eroding organic material can be found both on Earth and on Saturn's largest moon, Titan. However, on Titan it is methane, not water, that fills the lakes with slushy raindrops.

While trying to find the source of Titan's methane, University of Arizona researcher Caitlin Griffith and her team discovered something unexoldpected -- a long ice feature that wraps nearly half way around Titan.

Griffith, a professor in the UA Lunar and Planetary Laboratory, is the lead author on the paper published today in Nature Astronomy.

On Titan, atmospheric methane molecules are continuously broken apart by sunlight. The resulting atmospheric haze settles to the surface and accumulates as organic sediments, rapidly depleting the atmospheric methane.

This organic veneer is made up of the material of past atmospheres.

There is no obvious source of methane, except from the evaporation of methane from the polar lakes. But Titan's lakes contain only one-third of the methane in Titan's atmosphere and will be exhausted soon by geological time scales.

One theory is that the methane could be supplied by subsurface reservoirs that vent methane into the atmosphere. Prior studies of Titan indicate the presence of a singular region called Sotra, which looks like cryo-volcano, with icy flow features.

Griffith's team set out to study the composition of Titan's surface, partly hoping to find subtle small cryo-volcanos candidates. They analyzed half of Titan's surface and none were detected, but Sotra was found to be exceptional in that it exhibits the strongest ice features.

Yet the major ice feature the researchers found was completely unexpected. It consists of a linear ice corridor that wraps around 40 percent of Titan's circumference.

"This icy corridor is puzzling, because it doesn't correlate with any surface features nor measurements of the subsurface," Griffith said. "Given that our study and past work indicate that Titan is currently not volcanically active, the trace of the corridor is likely a vestige of the past. We detect this feature on steep slopes, but not on all slopes. This suggests that the icy corridor is currently eroding, potentially unveiling presence of ice and organic strata."

The team's analysis also indicates a diversity of organic material in certain regions. These surface deposits are of interest because laboratory simulations of Titan's atmosphere produce biologically interesting compounds such as amino acids.

Griffith analyzed tens of thousands of spectral images taken of the topmost layer of the surface by Cassini's Visible and Infrared Mapping Spectrometer, using a method that enabled the detection of weak surface features.

This feat was accomplished by Griffith's application of the principal components analysis, or PCA. It allowed her to tease out subtle features caused by ice and organic sediments on Titan's surface from the ubiquitous haze and more obvious surface features. Instead of measuring the surface features individually for each pixel in an image, the PCA uses all of the pixels to recognize the main and more subtle signatures.

Griffith's team compared their results with past studies including the Huygens probe, which landed on Titan in 2005. The comparison validated both the technique and the results. Plans are underway to use the technique to explore the poles where methane seas reside.

"Both Titan and Earth followed different evolutionary paths, and both ended up with unique organic-rich atmospheres and surfaces," Griffth said. "But it is not clear whether Titan and Earth are common blueprints of the organic-rich of bodies or two among many possible organic-rich worlds."

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What a dying star's ashes tell us about the birth of our solar system

Billions of years ago, before our solar system was born, a dead star known as a white dwarf in a nearby binary star system accumulated enough material from its companion to cause it to 'go nova.' The stellar explosion forged dust grains with exotic compositions not found in our solar system. A team of researchers led by the UA found such a grain (inset image), encased in a meteorite, that survived the formation of our solar system and analyzed it with instruments sensitive enough to ID single atoms in a sample. Measuring one 25,000th of an inch, the carbon-rich graphite grain (red) revealed an embedded speck of oxygen-rich material (blue), two types of stardust that were thought could not form in the same nova eruption.

A grain of dust forged in the death throes of a long-gone star was discovered by a team of researchers led by the University of Arizona.

The discovery challenges some of the current theories about how dying stars seed the universe with raw materials for the formation of planets and, ultimately, the precursor molecules of life.

Tucked inside a chondritic meteorite collected in Antarctica, the tiny speck represents actual stardust, most likely hurled into space by an exploding star before our own sun existed. Although such grains are believed to provide important raw materials contributing to the mix from which the sun and our planets formed, they rarely survive the turmoil that goes with the birth of a solar system.

"As actual dust from stars, such presolar grains give us insight into the building blocks from which our solar system formed," said Pierre Haenecour, lead author of the paper, which is scheduled for advance online publication on Nature Astronomy's website on Apr. 29. "They also provide us with a direct snapshot of the conditions in a star at the time when this grain was formed."

Dubbed LAP-149, the dust grain represents the only known assemblage of graphite and silicate grains that can be traced to a specific type of stellar explosion called a nova. Remarkably, it survived the journey through interstellar space and traveled to the region that would become our solar system some 4.5 billion years ago, perhaps earlier, where it became embedded in a primitive meteorite.

Novae are binary star systems in which a core remnant of a star, called a white dwarf, is on its way to fading out of the universe, while its companion is either a low-mass main sequence star or a red giant. The white dwarf then begins syphoning material off its bloated companion. Once it accretes enough new stellar material, the white dwarf re-ignites in periodic outbursts violent enough to forge new chemical elements from the stellar fuel and spew them deep into space, where they can travel to new stellar systems and become incorporated in their raw materials.

Since shortly after the Big Bang, when the universe consisted of only hydrogen, helium and traces of lithium, stellar explosions have contributed to the chemical enrichment of the cosmos, resulting in the plethora of elements we see today.

Taking advantage of sophisticated ion and electron microscopy facilities at the UA's Lunar and Planetary Laboratory, a research team led by Haenecour analyzed the microbe-sized dust grain down to the atomic level. The tiny messenger from outer space turned out to be truly alien -- highly enriched in a carbon isotope called 13C.

"The carbon isotopic compositions in anything we have ever sampled that came from any planet or body in our solar system varies typically by a factor on the order of 50," said Haenecour, who will join the Lunar and Planetary Laboratory as an assistant professor in the fall. "The 13C we found in LAP-149 is enriched more than 50,000-fold. These results provide further laboratory evidence that both carbon- and oxygen-rich grains from novae contributed to the building blocks of our solar system."

Although their parent stars no longer exist, the isotopic and chemical compositions and microstructure of individual stardust grains identified in meteorites provide unique constraints on dust formation and thermodynamic conditions in stellar outflows, the authors wrote.

Detailed analysis revealed even more unexpected secrets: Unlike similar dust grains thought to have been forged in dying stars, LAP-149 is the first known grain consisting of graphite that contains an oxygen-rich silicate inclusion.

"Our find provides us with a glimpse into a process we could never witness on Earth," Haenecour added. "It tells us about how dust grains form and move around inside as they are expelled by the nova. We now know that carbonaceous and silicate dust grains can form in the same nova ejecta, and they get transported across chemically distinct clumps of dust within the ejecta, something that was predicted by models of novae but never found in a specimen."

Unfortunately, LAP-149 does not contain enough atoms to determine its exact age, so researchers hope to find similar, larger specimens in the future.

"If we could date these objects someday, we could get a better idea of what our galaxy looked like in our region and what triggered the formation of the solar system," said Tom Zega, scientific director of the UA's Kuiper Materials Imaging and Characterization Facility and associate professor in the Lunar and Planetary Laboratory and UA Department of Materials Science and Engineering. "Perhaps we owe our existence to a nearby supernova explosion, compressing clouds of gas and dust with its shockwave, igniting stars and creating stellar nurseries, similar to what we see in Hubble's famous 'Pillars of Creation' picture."

The meteorite containing the speck of stardust is one of the most pristine meteorites in the Lunar and Planetary Laboratory's collection. Classified as a carbonaceous chondrite, it is believed to be analogous to the material on Bennu, the target asteroid of the UA-led OSIRIS-REx mission. By taking a sample of Bennu and bringing it back to Earth, the OSIRIS-REx mission team hopes to provide scientists with material that has seen little, if any, alteration since the formation of our solar system.

Until then, researchers depend on rare finds like LAP-149, which survived being blasted from an exploding star, caught in a collapsing cloud of gas and dust that would become our solar system and baked into an asteroid before falling to the earth.

Read more at Science Daily

The space rock that hit the moon at 61,000 kilometers an hour

The flash from the impact of the meteorite on the eclipsed Moon, seen as the dot at top left (indicated by the arrow in the image), as recorded by two of the telescopes operating in the framework of the MIDAS Survey from Sevilla (Spain) on 2019 January 21.

Observers watching January's total eclipse of the Moon saw a rare event, a short-lived flash as a meteorite hit the lunar surface. Spanish astronomers now think the space rock collided with the Moon at 61,000 kilometres an hour, excavating a crater 10 to 15 metres across. Prof Jose Maria Madiedo of the University of Huelva, and Dr Jose L. Ortiz of the Institute of Astrophysics of Andalusia, publish their results in a new paper in Monthly Notices of the Royal Astronomical Society.

Total lunar eclipses take place when the Moon moves completely into the shadow of the Earth. The Moon takes on a red colour -- the result of scattered sunlight refracted through the Earth's atmosphere -- but is much darker than normal. These spectacular events are regularly observed by astronomers and the wider public alike.

The most recent lunar eclipse took place on 21 January 2019, with observers in North and South America and Western Europe enjoying the best view. At 0441 GMT, just after the total phase of the eclipse began, a flash was seen on the lunar surface. Widespread reports from amateur astronomers indicated the flash -- attributed to a meteorite impact -- was bright enough to be seen with the naked eye.

Madiedo and Ortiz operate the Moon Impacts Detection and Analysis System (MIDAS), using eight telescopes in south of Spain to monitor the lunar surface. The impact flash lasted 0.28 seconds and is the first ever filmed during a lunar eclipse, despite a number of earlier attempts.

"Something inside of me told me that this time would be the time," said Madiedo, who was impressed when he observed the event, as it was brighter than most of the events regularly detected by the survey.

Unlike the Earth, the Moon has no atmosphere to protect it and so even small rocks can hit its surface. Since these impacts take place at huge speeds, the rocks are instantaneously vaporised at the impact site, producing an expanding plume of debris whose glow can be detected from our planet as short-duration flashes.

MIDAS telescopes observed the impact flash at multiple wavelengths (different colours of light), improving the analysis of the event. Madiedo and Ortiz conclude that the incoming rock had a mass of 45kg, measured 30 to 60 centimetres across, and hit the surface at 61,000 kilometres an hour. The impact site is close to the crater Lagrange H, near the west-south-west portion of the lunar limb.

The two scientists assess the impact energy as equivalent to 1.5 tonnes of TNT, enough to create a crater up to 15 metres across, or about the size of two double decker buses side by side. The debris ejected is estimated to have reached a peak temperature of 5400 degrees Celsius, roughly the same as the surface of the Sun.

Madiedo comments: "It would be impossible to reproduce these high-speed collisions in a lab on Earth. Observing flashes is a great way to test our ideas on exactly what happens when a meteorite collides with the Moon."

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Milky Way star with strange chemistry is from dwarf galaxy

The Subaru Telescope High Dispersion Spectrograph.

Astronomers have discovered a star in the Milky Way Galaxy with a chemical composition unlike any other star in our Galaxy. This chemical composition has been seen in a small number of stars in dwarf galaxies orbiting the Milky Way. This suggests that the star was part of a dwarf galaxy that merged into the Milky Way.

In the LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) survey data, researchers noticed the star J1124+4535 for its unusual chemical composition. Initial observations showed that J1124+4535, located in the constellation Ursa Major (Big Dipper), had low abundances of certain elements, such as magnesium. Follow-up observations with the High Dispersion Spectrograph on the Subaru Telescope confirmed the low levels of magnesium but found comparatively high levels of Europium. This is the first time an element ratio like this has been observed in a star in the Milky Way.

Stars form from clouds of interstellar gas. The element ratios of the parent cloud impart an observable chemical signature on stars formed in that cloud. So stars formed close together have similar element ratios. The composition of J1124+4535 doesn't match any other stars in the Milky Way, indicating that it must have formed elsewhere.

Chemical signatures similar to J1124+4535 have been observed in some stars in dwarf galaxies orbiting the Milky Way. Galaxy evolution models and simulations suggest that galaxies like the Milky Way grow by absorbing neighboring dwarf galaxies. Thus it makes sense that J1124+4535 was born in a now vanished dwarf galaxy which merged into the Milky Way.

From Science Daily

Astronomers discover 2,000-year-old remnant of a nova

Near the centre of the globular cluster Messier 22, the team of scientists discovered the remains of a nova.

For the first time, a European research team involving the University of Göttingen has discovered the remains of a nova in a galactic globular cluster. A nova is an explosion of hydrogen on the surface of a star which makes it much brighter. The remains have formed a glowing nebula. The remnant is located near the centre of the globular cluster Messier 22 and has recently been observed using modern instruments. The results will be published in the journal Astronomy & Astrophysics.

"The position and brightness of the remains match an entry from 48 BC in an ancient collection of observations by Chinese astronomers," says first author Fabian Göttgens of the Institute for Astrophysics at the University of Göttingen. This is research carried out for his PhD in the Stellar Astrophysics research group lead by Professor Dreizler. "They probably saw the original nova in the same place." This means modern measurements confirm one of the oldest observations of an event outside the solar system.

Globular clusters are large, spherical clusters of several hundreds of thousands of very old stars that orbit together around their home galaxy. There are 150 known globular clusters orbiting our galaxy, the Milky Way. Messier 22 is one of these star clusters, it lies in the constellation Sagittarius in the direction of the centre of the Milky Way. It was observed together with two dozen other globular clusters with the instrument MUSE at the Very Large Telescope of the ESO in Chile. The MUSE instrument was developed with the participation of the Institute for Astrophysics, which was funded by the BMBF. It does not only produce images, it also simultaneously splits starlight by colour, measuring the brightness of stars as a function of colour. This makes it particularly suitable for finding nebulae that often only glow in a certain colour -- usually red.

The newly discovered remains of the nova form a red shining nebula of hydrogen gas and other gases, which has a diameter of about 8,000 times the distance between Earth and Sun. Despite its size, the nebula is relatively light, with a mass about 30 times that of Earth, because the gas was dispersed by the explosion.

From Science Daily

Magma is the key to the moon's makeup

Snapshots of numerical modeling of the moon’s formation by a giant impact. The central part of the image is a proto-Earth; red points indicate materials from the ocean of magma in a proto-Earth; blue points indicate the impactor materials.

For more than a century, scientists have squabbled over how Earth's moon formed. But researchers at Yale and in Japan say they may have the answer.

Many theorists believe a Mars-sized object slammed into the early Earth, and material dislodged from that collision formed the basis of the moon. When this idea was tested in computer simulations, it turned out that the moon would be made primarily from the impacting object. Yet the opposite is true; we know from analyzing rocks brought back from Apollo missions that the moon consists mainly of material from Earth.

A new study published April 29 in Nature Geoscience, co-authored by Yale geophysicist Shun-ichiro Karato, offers an explanation.

The key, Karato says, is that the early, proto-Earth -- about 50 million years after the formation of the Sun -- was covered by a sea of hot magma, while the impacting object was likely made of solid material. Karato and his collaborators set out to test a new model, based on the collision of a proto-Earth covered with an ocean of magma and a solid impacting object.

The model showed that after the collision, the magma is heated much more than solids from the impacting object. The magma then expands in volume and goes into orbit to form the moon, the researchers say. This explains why there is much more Earth material in the moon's makeup. Previous models did not account for the different degree of heating between the proto-Earth silicate and the impactor.

"In our model, about 80% of the moon is made of proto-Earth materials," said Karato, who has conducted extensive research on the chemical properties of proto-Earth magma. "In most of the previous models, about 80% of the moon is made of the impactor. This is a big difference."

Karato said the new model confirms previous theories about how the moon formed, without the need to propose unconventional collision conditions -- something theorists have had to do until now.

For the study, Karato led the research into the compression of molten silicate. A group from the Tokyo Institute of Technology and the RIKEN Center for Computational Science developed a computational model to predict how material from the collision became the moon.

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Giant planets and big data: What deep learning reveals about Saturn's storms

Cloud distribution as mapped by PlanetNet across six overlapping data sets. The stormy region feature (blue) occurs in the vicinity of dark storms (purple/green) in contrast to the unperturbed regions (red/orange). The area covered by the multiple storm system is equivalent to about 70% of the Earth's surface.

A "deep learning" approach to detecting storms on Saturn is set to transform our understanding of planetary atmospheres, according to University College London and University of Arizona researchers.

The new technique, called PlanetNet, identifies and maps the components and features in turbulent regions of Saturn's atmosphere, giving insights into the processes that drive them.

A study, published today in Nature Astronomy, provides results from the first demonstration of the PlanetNet algorithm. The results clearly show the vast regions affected by storms and that dark storm clouds contain material swept up from the lower atmosphere by strong vertical winds.

Developed by UA and UCL researchers, PlanetNet was trained and tested using infrared data from the Visible and Infrared Mapping Spectrometer instrument on Cassini, a joint mission between NASA, the European Space Agency and the Italian Space Agency.

A dataset containing multiple, adjacent storms observed at Saturn in February 2008 was chosen to provide a range of complex atmospheric features to challenge PlanetNet's capabilities.

"PlanetNet enables us to analyze much bigger volumes of data, and this gives insights into the large-scale dynamics of Saturn," said UA professor Caitlin Griffith, who co-authored the paper. "The results reveal atmospheric features that were previously undetected. PlanetNet can easily be adapted to other datasets and planets, making it an invaluable potential tool for many future missions."

Previous analysis of the dataset indicated a rare detection of ammonia in Saturn's atmosphere, in the form of an S-shaped cloud.

The map produced through PlanetNet shows that this feature is a prominent part of a much larger upwelling of ammonia ice clouds around a central dark storm. PlanetNet identifies similar upwelling around another small storm, suggesting such features are quite common.

The map also shows pronounced differences between the center of storms and the surrounding areas, indicating that the eye gives a clear view into the warmer, deep atmosphere.

"Missions like Cassini gather enormous amounts of data, but classical techniques for analysis have drawbacks, either in the accuracy of information that can be extracted or in the time they take to perform. Deep learning enables pattern recognition across diverse, multiple data sets," said Ingo Waldmann, lead author and deputy director of the UCL Centre for Space and Exoplanet Data.

"This gives us the potential to analyze atmospheric phenomena over large areas and from different viewing angles, and to make new associations between the shape of features and the chemical and physical properties that create them," he said.

Initially, PlanetNet searches the data for signs of clustering in the cloud structure and gas composition. For areas of interest, it trims the data to remove uncertainties at the edges and runs a parallel analysis of the spectral and spatial properties. Recombining the two data streams, PlanetNet creates a map that presents quickly and accurately the major components of Saturn's storms with unprecedented precision.

PlanetNet's accuracy has been validated on Cassini data not included in the training phase. The whole dataset has also been rotated and resampled to create synthetic data for further testing. PlanetNet has achieved over 90 percent classification accuracy in both test cases.

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Spinning black hole sprays light-speed plasma clouds into space

Artist's impression of jet ejections in V404 Cygni. With our radio telescopes, we see individual bright clouds of plasma that have been ejected from the innermost regions, and redirected by the puffed-up inner accretion disk.

Astronomers have discovered rapidly swinging jets coming from a black hole almost 8000 light-years from Earth.

Published today in the journal Nature, the research shows jets from V404 Cygni's black hole behaving in a way never seen before on such short timescales.

The jets appear to be rapidly rotating with high-speed clouds of plasma -- potentially just minutes apart -- shooting out of the black hole in different directions.

Lead author Associate Professor James Miller-Jones, from the Curtin University node of the International Centre for Radio Astronomy Research (ICRAR), said black holes are some of the most extreme objects in the Universe.

"This is one of the most extraordinary black hole systems I've ever come across," Associate Professor Miller-Jones said.

"Like many black holes, it's feeding on a nearby star, pulling gas away from the star and forming a disk of material that encircles the black hole and spirals towards it under gravity.

"What's different in V404 Cygni is that we think the disk of material and the black hole are misaligned. "This appears to be causing the inner part of the disk to wobble like a spinning top and fire jets out in different directions as it changes orientation."

V404 Cygni was first identified as a black hole in 1989 when it released a big outburst of jets and radiation.

Astronomers looking at archival photographic plates then found previous outbursts in observations from 1938 and 1956.

Associate Professor Miller-Jones said that when V404 Cygni experienced another very bright outburst in 2015, lasting for two weeks, telescopes around the world tuned in to study what was going on.

"Everybody jumped on the outburst with whatever telescopes they could throw at it," he said.

"So we have this amazing observational coverage."

When Associate Professor Miller-Jones and his team studied the black hole, they saw its jets behaving in a way never seen before.

Where jets are usually thought to shoot straight out from the poles of black holes, these jets were shooting out in different directions at different times.

And they were changing direction very quickly -- over no more than a couple of hours.

Associate Professor Miller-Jones said the change in the movement of the jets was because of the accretion disk -- the rotating disk of matter around a black hole.

He said V404 Cygni's accretion disk is 10 million kilometres wide, and the inner few thousand kilometres was puffed up and wobbling during the bright outburst.

"The inner part of the accretion disk was precessing and effectively pulling the jets around with it," Associate Professor Miller-Jones said.

"You can think of it like the wobble of a spinning top as it slows down -- only in this case, the wobble is caused by Einstein's theory of general relativity."

The research used observations from the Very Long Baseline Array, a continent-sized radio telescope made up of 10 dishes across the United States, from the Virgin Islands in the Caribbean to Hawaii.

Co-author Alex Tetarenko -- a recent PhD graduate from the University of Alberta and currently an East Asian Observatory Fellow working in Hawaii -- said the speed the jets were changing direction meant the scientists had to use a very different approach to most radio observations.

"Typically, radio telescopes produce a single image from several hours of observation," she said.

"But these jets were changing so fast that in a four-hour image we just saw a blur.

"It was like trying to take a picture of a waterfall with a one-second shutter speed." Instead, the researchers produced 103 individual images, each about 70 seconds long, and joined them together into a movie.

"It was only by doing this that we were able to see these changes over a very short time period," Dr Tetarenko said.

Study co-author Dr Gemma Anderson, who is also based at ICRAR's Curtin University node, said the wobble of the inner accretion disk could happen in other extreme events in the Universe too.

"Anytime you get a misalignment between the spin of a black hole and the material falling in, you would expect to see this when a black hole starts feeding very rapidly," Dr Anderson said.

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Chemists manipulate the quantum states of gold nanoclusters

Carnegie Mellon chemists created a 30-atom gold nanocluster with a hcp structure, which has a quantum lifetime of one nanosecond and a 38-atom gold nanocluster with a bcc structure, which has a quantum lifetime of 4.7 microseconds.

Researchers from Carnegie Mellon University's Department of Chemistry have found a way to control the lifetime of the quantum states of gold nanoclusters by three orders of magnitude, which could lead to improvements in solar cell and photocatalysis technologies. Their study is published in the April 18 issue of Science.

Excited quantum states occur when light is absorbed by a particle and the energy from that light is temporarily stored within the particle, making its energy higher than its ground state. The energy decays quickly and can be lost as heat in the span of a nanosecond, or one billionth of a second. Extending this quantum state could provide researchers with more time and opportunity to harness the stored energy.

Carnegie Mellon Chemistry Professor Rongchao Jin is known for developing precisely sized gold nanoparticles. In this extension of his work, post-doctoral researcher Meng Zhou and Ph.D. student Tatsuya Higaki, who are co-first authors of the paper, studied atomically precise gold nanoclusters containing between 30 and 38 atoms. They altered the structures of clusters by rearranging the atoms into exotic configurations and protecting them with a capping ligand.

The researchers measured the lifetimes of the nanoclusters' quantum states by using femtosecond and nanosecond time-resolved spectroscopy to take snapshots of the nanoclusters from the time when they absorbed energy from light, in this case a femtosecond laser pulse, until they released the energy. Collaborators at University of California, Riverside confirmed the results using density function theory calculations to analyze the molecular orbitals of the nanoclusters.

They found that a 30-atom gold nanocluster, with a hexagonal close-packed (hcp) structure, had a quantum lifetime of one nanosecond. But a 38-atom gold nanocluster with a body-centered cubic (bcc) structure had a much longer lifetime of 4.7 microseconds. Extending the lifetime by three magnitudes gives researchers ample time to extract the absorbed light energy from the nanoclusters -- a finding that has significant implications.

"The strategy of manipulating the excited-state lifetime from very short to very long is exciting. The exceptionally long quantum lifetime of 4.7 microseconds is comparable to that of bulk silicon, which is used for commercial solar cells," said Jin. "It should give us enough time to efficiently extract the energy into external circuits as an electronic current without losing too much energy to heat."

The tailored quantum lifetime can also be used to increase the efficiency of visible light-based photocatalysis used to convert solar energy storage into chemicals, such as converting methanol and ethanol from carbon dioxide.

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No safe amount of alcohol during pregnancy, suggest researchers

An international group of researchers has taken one of the first major steps in finding the biological changes in the brain that drive fetal alcohol spectrum disorder (FASD). New work using chaos theory to analyze brain signals, discussed this month in the journal Chaos, from AIP Publishing, shows the long-term effects.

Researchers found that teenagers who were exposed to alcohol while in the womb showed altered brain connections that were consistent with impaired cognitive performance. Their findings were reached by measuring the responses from a brain imaging technique called magnetoencephalography (MEG) and then analyzing them with tools developed using chaos theory.

FASD is one of the leading causes of intellectual disability worldwide and is linked to a wide array of neurological issues, including ADHD. While the prevailing theory links expectant mothers' alcohol consumption to cognitive impairments for children, questions about the extent of this effect remain. Despite the known link, researchers are uncertain about the precise mechanism by which alcohol alters the developing brain.

The group's efforts mark one of the first times researchers have been able to quantify the effects of alcohol exposure on the developing brain.

"The paper provides important integrative results for the field of FASD," said Julia Stephen, an author on the paper. "These results may then indicate that simple sensory measures may provide sensitivity for brain deficits that affect the broader cognitive domain."

Previous attempts to study the brain circuitry in affected individuals have been hampered by the difficulty of drawing conclusions from complicated MEG data.

To get to the heart of the problem, members of the team developed a sophisticated computer technique called Cortical Start Spatio-Temporal multidipole analysis that could identify which areas of the brain were active when research subjects were in the MEG machine.

After data from 19 FASD patients and 21 subjects without FASD was collected, the computational approach revealed several areas of the brain that showed impaired connectivity among the FASD group.

Subjects who were exposed to alcohol in the womb were more likely to have issues with connections through their corpus callosum, the band of brain tissue that connects the left and right halves of the brain. Deficits in this area have been reported in people with schizophrenia, multiple sclerosis, autism, depression and abnormalities in sensation.

"This work presents major evidence that children exposed to alcohol prenatally are at risk of suffering from impaired cognitive abilities and other secondary factors," said Lin Gao, an author on the paper. "Our study ... shows that there is no safe amount or safe stages during pregnancy for alcohol consumption."

Read more at Science Daily