The cosmic commute towards star and planet formation

Interconnected gas flows reveal how star-forming gas is assembled in galaxies

MAX-PLANCK-GESELLSCHAFT

 

IMAGE: IMAGE OF THE MOLECULAR GAS (CARBON MONOXIDE) DISTRIBUTION IN THE SOUTHERN SPIRAL ARM OF THE GALAXY NGC 4321 SPANNING ROUGHLY 15,000 LIGHT YEARS ACROSS. THE BRIGHT SPOTS INDICATE GIANT MOLECULAR... view more 

CREDIT: J. HENSHAW/MPIA

The molecular gas in galaxies is organised into a hierarchy of structures. The molecular material in giant molecular gas clouds travels along intricate networks of filamentary gas lanes towards the congested centres of gas and dust where it is compressed into stars and planets, much like the millions of people commuting to cities for work around the world.

To better understand this process, a team of astronomers led by Jonathan Henshaw at Max Planck Institute for Astronomy (MPIA) have measured the motion of gas flowing from galaxy scales down to the scales of the gas clumps within which individual stars form. Their results show that the gas flowing through each scale is dynamically interconnected: while star and planet formation occurs on the smallest scales, this process is controlled by a cascade of matter flows that begin on galactic scales. These results are published today in the scientific journal Nature Astronomy.

The molecular gas in galaxies is set into motion by physical mechanisms such as galactic rotation, supernova explosions, magnetic fields, turbulence, and gravity, shaping the structure of the gas. Understanding how these motions directly impact star and planet formation is difficult, because it requires quantifying gas motion over a huge range in spatial scale, and then linking this motion to the physical structures we observe. Modern astrophysical facilities now routinely map huge areas of the sky, with some maps containing millions of pixels, each with hundreds to thousands of independent velocity measurements. As a result, measuring these motions is both scientifically and technologically challenging.

In order to address these challenges, an international team of researchers led by Jonathan Henshaw at the MPIA in Heidelberg set out to measure gas motions throughout a variety of different environments using observations of the gas in the Milky Way and a nearby galaxy. They detect these motions by measuring the apparent change in the frequency of light emitted by molecules caused by the relative motion between the source of the light and the observer; a phenomenon known as the Doppler effect. By applying novel software designed by Henshaw and Ph.D. student Manuel Riener (a co-author on the paper; also at MPIA), the team were able to analyse millions of measurements. "This method allowed us to visualise the interstellar medium in a new way," says Henshaw.

The researchers found that cold molecular gas motions appear to fluctuate in velocity, reminiscent in appearance of waves on the surface of the ocean. These fluctuations represent gas motion. "The fluctuations themselves weren't particularly surprising, we know that the gas is moving," says Henshaw. Steve Longmore, co-author of the paper, based at Liverpool John Moores University, adds, "What surprised us was how similar the velocity structure of these different regions appeared. It didn't matter if we were looking at an entire galaxy or an individual cloud within our own galaxy, the structure is more or less the same."

To better understand the nature of the gas flows, the team selected several regions for close examination, using advanced statistical techniques to look for differences between the fluctuations. By combining a variety of different measurements, the researchers were able to determine how the velocity fluctuations depend on the spatial scale.

"A neat feature of our analysis techniques is that they are sensitive to periodicity," explains Henshaw. "If there are repeating patterns in your data, such as equally spaced giant molecular clouds along a spiral arm, we can directly identify the scale on which the pattern repeats." The team identified three filamentary gas lanes, which, despite tracing vastly different scales, all seemed to show structure that was roughly equidistantly spaced along their crests, like beads on a string, whether it was giant molecular clouds along a spiral arm or tiny "cores" forming stars along a filament.

The team discovered that the velocity fluctuations associated with equidistantly spaced structure all showed a distinctive pattern. "The fluctuations look like waves oscillating along the crests of the filaments, they have a well-defined amplitude and wavelength," says Henshaw adding, "The periodic spacing of the giant molecular clouds on large-scales or individual star-forming cores on small-scales is probably the result of their parent filaments becoming gravitationally unstable. We believe that these oscillatory flows are the signature of gas streaming along spiral arms or converging towards the density peaks, supplying new fuel for star formation."

In contrast, the team found that the velocity fluctuations measured throughout giant molecular clouds, on scales intermediate between entire clouds and the tiny cores within them, show no obvious characteristic scale. Diederik Kruijssen, co-author of the paper based at Heidelberg University explains: "The density and velocity structures that we see in giant molecular clouds are 'scale-free', because the turbulent gas flows generating these structures form a chaotic cascade, revealing ever smaller fluctuations as you zoom in - much like a Romanesco broccoli, or a snowflake. This scale-free behaviour takes place between two well-defined extremes: the large scale of the entire cloud, and the small scale of the cores forming individual stars. We now find that these extremes have well-defined characteristic sizes, but in between them chaos rules."

"Picture the giant molecular clouds as equally-spaced mega-cities connected by highways," says Henshaw. "From a birds eye view, the structure of these cities, and the cars and people moving through them, appears chaotic and disordered. However, when we zoom in on individual roads, we see people who have travelled from far and wide entering their individual office buildings in an orderly fashion. The office buildings represent the dense and cold gas cores from which stars and planets are born."

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Original publication

Henshaw, J.D., Kruijssen, J.M.D., Longmore, S.N. et al. Ubiquitous velocity fluctuations throughout the molecular interstellar medium. Nat Astron (2020).

Climate change may cause extreme waves in Arctic

AMERICAN GEOPHYSICAL UNION

IMAGE: A WAVE WASHING UP ON THE INUVIALUIT HAMLET OF TUKTOYAKTUK IN CANADA'S NORTHWEST TERRITORIES DURING AN AUGUST 2019 STORM. view more 

CREDIT: WERONIKA MURRAY

WASHINGTON--Extreme ocean surface waves with a devastating impact on coastal communities and infrastructure in the Arctic may become larger due to climate change, according to a new study.

The new research projects the annual maximum wave height will get up to two to three times higher than it is now along coastlines in areas of the Arctic such as along the Beaufort Sea. The new study in AGU's Journal of Geophysical Research: Oceans suggests waves could get up to 2 meters (6.6 feet) higher than current wave heights by the end of the century.

In addition, extreme wave events that used to occur once every 20 years might increase to occur once every two to five years on average, according to the study. In other words, the frequency of such extreme coastal flooding might increase by a factor of 4 to 10 by the end of this century.

"It increases the risk of flooding and erosion. It increases drastically almost everywhere," said Mercè Casas-Prat, a research scientist with Environment and Climate Change Canada's (ECCC) Climate Research Division and the lead author of the new study. "This can have a direct impact to the communities that live close to the shoreline."

Climate change in the Arctic

Earth's northernmost regions are a global warming hotspot, with some areas experiencing up to three times the warming of the rest of the world, Casas-Prat said. But researchers lack information on how the impacts may play out.

Casas-Prat and her co-author Xiaolan Wang, also with the ECCC, wanted to examine how global warming might impact extreme ocean surface waves in the Arctic. Casas-Prat said some northern communities are already reporting accelerated erosion in some areas and increased building damage due to extreme waves. A worsening of these ocean conditions will have a direct impact on coastal communities, energy infrastructure, shipping, and even ecosystems and wildlife.

Much of the Arctic is frozen for most of the year, but the warming climate is contributing to increasing periods of open water, which can become an issue when extreme waves are factored into the equation.

In the new study, the scientists gathered five sets of multi-model simulations of oceanic and atmospheric conditions like surface winds, which generate waves, as well as sea ice for the RCP8.5 scenario, a future scenario commonly used in climate change projections that assumes low efforts to curb emissions. Then they ran simulations of wave conditions for two periods, from 1979 to 2005 (historical), then from 2081 to 2100 (future). Using the ensemble of multi-model simulations, they were able to assess the uncertainty in the changes in the extreme Arctic waves due to the uncertainty present in the five climate models used.

One of their main findings was a projected notable wave height increase between these two periods in almost every place in the Arctic.

Among the hardest-hit areas was in the Greenland Sea, which lies between Greenland and the Norwegian archipelago of Svalbard. The study found maximum annual wave heights there could increase by as much as 6 meters (19.7 feet).

Casas-Prat said the models present a degree of uncertainty about how much waves heights might change, but she is confident there is going to be an increase. The researchers' predictions also showed that by the end of the century, the timing of the highest waves may also change.

"At the end of the century, the maximum will on average come later in the year and also be more extreme," Casas-Prat said.

Impact on communities

Judah Cohen, a climatologist at the Massachusetts Institute of Technology who was not involved in Casas-Prat's research, said these waves could be particularly devastating to coastal areas that have never previously experienced open water.

"The main conclusions of the paper are that waves will increase in height in the Arctic region and that Arctic coastlines are at greater risk to erosion and flooding are fairly straightforward," he said. "We are already seeing these increased risks along Arctic coastlines with damage to coastline structures that previously were never damaged."

The researchers examined one area of coastline along the Beaufort Sea in northern Alaska and Canada, which holds a number of communities as well as energy infrastructure, and also found notable wave height increases there.

Since larger waves can lead to increased risks of flooding and damage to coastal infrastructure, communities and development in this area might be affected by these waves. Flooding can also impact the availability of fresh water in some areas, as storm and wave surges can get into freshwater lagoons that communities rely on.

"As more and more ice melts and more of the Arctic ocean surface becomes exposed to the wind, waves will increase in height because wave height is dependent on the distance the wind blows over open waters," Cohen said.

In another recent study published in AGU's journal Geophysical Research Letters, Casas-Prat and Wang examined the contribution of sea ice retreat on the projected increases in extreme wave heights in the Arctic. They found that surface winds alone cannot explain the changes in the regional maximum wave heights.

"Sea ice retreat plays an important role, not just by increasing the distance over which wind can blow and generate waves but also by increasing the chance of strong winds to occur over widening ice-free waters," Casas-Prat said.

Increased waves could also increase the speed of ice breakup. The loss of ice due to waves could affect animals like polar bears which hunt seals on polar ice as well as a number of other creatures that rely on ice. It could also affect shipping routes in the future.

"Waves definitely have to be taken into account as an important factor to ensure those routes are safe," Casas-Prat said.

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This press release and accompanying images are available online at: http://news.agu.org/press-release/climate-change-may-cause-extreme-waves-in-arctic/

AGU press contact:

Lauren Lipuma
+1 (202) 777-7396
news@agu.org

Contact information for the researchers:

Mercè Casas-Prat, Environment and Climate Change Canada
merce.casasprat@canada.ca

AGU is an international association of more than 60,000 advocates and experts in Earth and space science. Through our initiatives, such as mentoring, professional development and awards, AGU members uphold and foster an inclusive and diverse scientific community. AGU also hosts numerous conferences, including the largest international Earth and space science meeting as well as serving as the leading publisher of the highest quality journals. Fundamental to our mission since our founding in 1919 is to live our values, which we do through our net zero energy building in Washington, D.C. and making the scientific discoveries and research accessible and engaging to all to help protect society and prepare global citizens for the challenges and opportunities ahead.

Notes for Journalists

This paper is freely available through August 15. Download a PDF copy of the article here.

Journalists may also request a copy of the final paper by emailing Lauren Lipuma at news@agu.org. Please provide your name, the name of your publication, and your phone number.

Neither the paper nor this press release is under embargo.

Paper title:

"Projections of extreme ocean waves in the Arctic and potential implications for coastal inundation and erosion"

Authors:

Mercè Casas-Prat, Xiaolan L. Wang: Climate Research Division, Science and Technology Directorate, Environment and Climate Change Canada, Toronto, Ontario, Canada.

Additional press contacts:

New collection of stars, not born in our galaxy, discovered in Milky Way

Caltech researchers use deep learning and supercomputing to identify Nyx, a product of a long-ago galaxy merger

UNIVERSITY OF TEXAS AT AUSTIN, TEXAS ADVANCED COMPUTING CENTER

 

IMAGE: STILL FROM A SIMULATION OF INDIVIDUAL GALAXIES FORMING, STARTING AT A TIME WHEN THE UNIVERSE WAS JUST A FEW MILLION YEARS OLD. view more 

CREDIT: HOPKINS RESEARCH GROUP, CALTECH

Astronomers can go their whole career without finding a new object in the sky. But for Lina Necib, a postdoctoral scholar in theoretical physics at Caltech, the discovery of a cluster of stars in the Milky Way, but not born of the Milky Way, came early - with a little help from supercomputers, the Gaia space observatory, and new deep learning methods.

Writing in Nature Astronomy this week, Necib and her collaborators describe Nyx, a vast new stellar stream in the vicinity of the Sun, that may provide the first indication that a dwarf galaxy had merged with the Milky Way disk. These stellar streams are thought to be globular clusters or dwarf galaxies that have been stretched out along its orbit by tidal forces before being completely disrupted.

The discovery of Nyx took a circuitous route, but one that reflects the multifaceted way astronomy and astrophysics are studied today.

FIRE in the Cosmos

Necib studies the kinematics -- or motions -- of stars and dark matter in the Milky Way. "If there are any clumps of stars that are moving together in a particular fashion, that usually tells us that there is a reason that they're moving together."

Since 2014, researchers from Caltech, Northwestern University, UC San Diego and UC Berkeley, among other institutions, have been developing highly-detailed simulations of realistic galaxies as part of a project called FIRE (Feedback In Realistic Environments). These simulations include everything scientists know about how galaxies form and evolve. Starting from the virtual equivalent of the beginning of time, the simulations produce galaxies that look and act much like our own.

Mapping the Milky Way

Concurrent to the FIRE project, the Gaia space observatory was launched in 2013 by the European Space Agency. Its goal is to create an extraordinarily precise three-dimensional map of about one billion stars throughout the Milky Way galaxy and beyond.

"It's the largest kinematic study to date. The observatory provides the motions of one billion stars," she explained. "A subset of it, seven million stars, have 3D velocities, which means that we can know exactly where a star is and its motion. We've gone from very small datasets to doing massive analyses that we couldn't do before to understand the structure of the Milky Way."

The discovery of Nyx involved combining these two major astrophysics projects and analyzing them using deep learning methods.

Among the questions that both the simulations and the sky survey address is: How did the Milky Way become what it is today?

"Galaxies form by swallowing other galaxies," Necib said. "We've assumed that the Milky Way had a quiet merger history, and for a while it was concerning how quiet it was because our simulations show a lot of mergers. Now, with access to a lot of smaller structures, we understand it wasn't as quiet as it seemed. It's very powerful to have all these tools, data and simulations. All of them have to be used at once to disentangle this problem. We're at the beginning stages of being able to really understand the formation of the Milky way."

Applying Deep Learning to Gaia

A map of a billion stars is a mixed blessing: so much information, but nearly impossible to parse by human perception.

"Before, astronomers had to do a lot of looking and plotting, and maybe use some clustering algorithms. But that's not really possible anymore," Necib said. "We can't stare at seven million stars and figure out what they're doing. What we did in this series of projects was use the Gaia mock catalogues."

The Gaia mock catalogue, developed by Robyn Sanderson (University of Pennsylvania), essentially asked: 'If the FIRE simulations were real and observed with Gaia, what would we see?'

Necib's collaborator, Bryan Ostdiek (formerly at University of Oregon, and now at Harvard University), who had previously been involved in the Large Hadron Collider (LHC) project, had experience dealing with huge datasets using machine and deep learning. Porting those methods over to astrophysics opened the door to a new way to explore the cosmos.

"At the LHC, we have incredible simulations, but we worry that machines trained on them may learn the simulation and not real physics," Ostdiek said. "In a similar way, the FIRE galaxies provide a wonderful environment to train our models, but they are not the Milky Way. We had to learn not only what could help us identify the interesting stars in simulation, but also how to get this to generalize to our real galaxy."

The team developed a method of tracking the movements of each star in the virtual galaxies and labelling the stars as either born in the host galaxy or accreted as the products of galaxy mergers. The two types of stars have different signatures, though the differences are often subtle. These labels were used to train the deep learning model, which was then tested on other FIRE simulations.

After they built the catalogue, they applied it to the Gaia data. "We asked the neural network, 'Based on what you've learned, can you label if the stars were accreted or not?'" Necib said.

The model ranked how confident it was that a star was born outside the Milky Way on a range from 0 to 1. The team created a cutoff with a tolerance for error and began exploring the results.

This approach of applying a model trained on one dataset and applying it to a different but related one is called transfer learning and can be fraught with challenges. "We needed to make sure that we're not learning artificial things about the simulation, but really what's going on in the data," Necib said. "For that, we had to give it a little bit of help and tell it to reweigh certain known elements to give it a bit of an anchor."

They first checked to see if it could identify known features of the galaxy. These include "the Gaia sausage" -- the remains of a dwarf galaxy that merged with the Milky Way about six to ten billion years ago and that has a distinctive sausage-like orbital shape.

"It has a very specific signature," she explained. "If the neural network worked the way it's supposed to, we should see this huge structure that we already know is there."

The Gaia sausage was there, as was the stellar halo -- background stars that give the Milky Way its tell-tale shape -- and the Helmi stream, another known dwarf galaxy that merged with the Milky Way in the distant past and was discovered in 1999.

First Sighting: Nyx

The model identified another structure in the analysis: a cluster of 250 stars, rotating with the Milky Way's disk, but also going toward the center of the galaxy.

"Your first instinct is that you have a bug," Necib recounted. "And you're like, 'Oh no!' So, I didn't tell any of my collaborators for three weeks. Then I started realizing it's not a bug, it's actually real and it's new."

But what if it had already been discovered? "You start going through the literature, making sure that nobody has seen it and luckily for me, nobody had. So I got to name it, which is the most exciting thing in astrophysics. I called it Nyx, the Greek goddess of the night. This particular structure is very interesting because it would have been very difficult to see without machine learning."

The project required advanced computing at many different stages. The FIRE and updated FIRE-2 simulations are among the largest computer models of galaxies ever attempted. Each of the nine main simulations -- three separate galaxy formations, each with slightly different starting point for the sun -- took months to compute on the largest, fastest supercomputers in the world. These included Blue Waters at the National Center for Supercomputing Applications (NCSA), NASA's High-End Computing facilities, and most recently Stampede2 at the Texas Advanced Computing Center (TACC).

The researchers used clusters at the University of Oregon to train the deep learning model and to apply it to the massive Gaia dataset. They are currently using Frontera, the fastest system at any university in the world, to continue the work.

"Everything about this project is computationally very intensive and would not be able to happen without large-scale computing," Necib said.

Future Steps

Necib and her team plan to explore Nyx further using ground-based telescopes. This will provide information about the chemical makeup of the stream, and other details that will help them date Nyx's arrival into the Milky Way, and possibly provide clues on where it came from.

The next data release of Gaia in 2021 will contain additional information about 100 million stars in the catalogue, making more discoveries of accreted clusters likely.

"When the Gaia mission started, astronomers knew it was one of the largest datasets that they were going to get, with lots to be excited about," Necib said. "But we needed to evolve our techniques to adapt to the dataset. If we didn't change or update our methods, we'd be missing out on physics that are in our dataset."

The successes of the Caltech team's approach may have an even bigger impact. "We're developing computational tools that will be available for many areas of research and for non-research related things, too," she said. "This is how we push the technological frontier in general."

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Survey: 7 in 10 respondents worry poor health will limit their life experiences

AMERICAN HEART ASSOCIATION

DALLAS and ARLINGTON Va., July 7, 2020 -- Seven in 10 U.S. adults worry poor health will prevent them from doing all the things they'd like to do in life, according to a new survey[1] from the American Heart Association and American Diabetes Association.

The research was conducted by OnePoll for Know Diabetes by Heart™, a joint initiative of the American Heart Association and the American Diabetes Association which combats two of the most persistent U.S. health threats - type 2 diabetes and cardiovascular disease - and the devastating link between them.

The survey asked 2,000 U.S. adults how the COVID-19 pandemic has impacted their views on time with friends and family, and generally, the role health plays in experiencing a full life.

Missing out on milestones and time with loved ones is a reality for millions of people in the U.S. living with type 2 diabetes. In addition to being at a higher risk of death from COVID-19 if blood glucose is poorly controlled,[2] people with type 2 diabetes are at double the risk of developing and dying from heart disease and stroke.[3],[4],[5] For adults at age 60, having type 2 diabetes and cardiovascular disease such as heart attacks, heart failure and strokes shortens life expectancy by an average of 12 years,[6] but there is a lot people can do to lower their risk.

The survey found respondents with type 2 diabetes, heart disease or stroke are more worried that health will limit their experiences (89%, 90% and 87%, respectively) compared to respondents who don't have those conditions (58%).

Generation Comparison Reveals Differences

About two in three (65%) respondents are worried their loved ones won't be healthy enough to experience various life moments with them. Millennials (ages 24-39) and Generation X (ages 40-55) were most worried, 73% and 69% respectively, compared to 59% for Generation Z (ages 18-23) and 58% for baby boomers (ages 56+).

Gen Z respondents are most worried about health preventing them from experiencing everything they'd like to do in life (75%), while baby boomers, are least worried overall (63%). Baby boomers however, report the highest percentage of prioritizing their health more as they've gotten older, 68%, compared to 34% for Gen Z, 48% for millennials and 65% for Gen X.

COVID-19 Pandemic Created Greater Appreciation for Daily Moments with Loved Ones

Survey results revealed the COVID-19 pandemic has changed the way many think about daily moments, and how respondents view their experiences with others. Eight in 10 respondents said the pandemic has made daily moments with their loved ones more special. Even more, 85%, said the pandemic has made them more grateful for the time they spend with their loved ones.

Eduardo Sanchez, M.D., MPH, FAAFP, American Heart Association chief medical officer for prevention, said COVID-19 shines a direct spotlight on chronic health conditions and the additional health risks they present.

"Controlling blood glucose and managing and modifying risk factors for heart disease and stroke has never been more important," Sanchez said. "If there's a silver lining in all of this, perhaps it's a new appreciation for wellness and emphasis on controlling the controllable, the existing threats to our health that we know more about and have more tools to manage."

Returning to Routine Medical Care

Robert H. Eckel, M.D., American Diabetes Association president of medicine and science and an endocrinologist at the University of Colorado School of Medicine, emphasized the need for regular, routine medical care and expressed concern that many patients canceled or postponed doctor appointments during the pandemic.

"If you want to have the full life you are hoping for on the other side of COVID-19, then resume your doctor appointments, check your health numbers, like blood glucose - and if you have diabetes your hemoglobin A1c - cholesterol and blood pressure, and get a plan for preventing heart disease and stroke," said Eckel. "Taking medications as prescribed is also an important thing you can do for yourself and the people you love."

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Visit KnowDiabetesbyHeart.org/join for practical information and recipes to help people with type 2 diabetes live a longer, healthier life.

USA As teens delay driver licensing, they miss key safety instruction

YALE UNIVERSITY

 

New Haven, Conn. -- Teens are getting licensed to drive later than they used to and missing critical safety training as a result, according to Yale researchers.

In a study in the July 2 edition of the Journal of Adolescent Health, researchers at Yale identified some of the factors contributing to delaying driving licensure, or DDL, and pointed to policy changes that could expand safety training regardless of age.

When teens delay getting their driver's licenses, said lead author Dr. Federico E. Vaca, professor of emergency medicine and director of the Yale Developmental Neurocognitive Driving Simulation Research Center (DrivSim Lab), they age out of these safety measures which are not required after a person turns 18. "On the day I turned 16, I was at the DMV getting my license," said Vaca. "Now, that's not happening. We wanted to know, why not?"

The study found that race, socioeconomic status, and parenting are all important factors.

From 2006 to 2016, the proportion of high school seniors with driver's licenses fell from 81% to 72%, and at least 70% of eligible adolescents delay licensing by at least one year, the study noted. These delays affect the extent to which these young drivers participate a program known as Graduated Driver Licensing (GDL), requirements that young drivers must meet before they have a fully independent license. The GDL program, some version of which exists in all 50 states, typically requires 16-year-olds to log a certain number of hours of practice driving with a parent or guardian during a learner's permit stage, and later restricts late-night driving and driving with young passengers. Many states also include restrictions on cell phone use in the car as part of the GDL.

"These are key restrictions," said Vaca. "All the epidemiology shows that the later you drive at night, the more dangerous it is. "Once you get past 9 or 10 p.m., the fatal crash rate goes up. We also know from the literature that, for young drivers, the risk of fatal crashes also goes up with the number of passengers in the car."

GDL addresses these facts, and the programs have been successful in promoting safer driving, Vaca said. After GDL programs were introduced in the U.S. in the mid-nineties, fatal crashes among teens declined by 74% among 16-year-olds, by 61% among 17-year-olds, by 55% among 18-year-olds, and by 45% among 19-year-olds.

The researchers found that certain racial, ethnic, and socioeconomic groups are delaying licensure at higher rates -- in particular Latino and black teens. Using data from the National Institutes of Health's NEXT Generation Health Study, which followed a cohort of 10th grade students into adulthood, the Yale researchers found that Latino teens were 4.5 times as likely as white teens to delay getting their licenses by over two years and black teens were 2.3 times as likely.

Furthermore, they found that teens whose parents' highest educational degree level was high school were 3.7 times more likely to delay by over two years than those whose parents had a college degree. Teens from poor families were 4.4 times as likely to delay for more than two years compared to those from affluent families. Teens who perceived that their mothers were actively involved in their lives and monitoring their behaviors were less likely to delay their driving licensure. A similar effect was not seen with fathers.

When young people don't start driving until their early 20s, said Vaca, they are navigating a much more complicated world, where exposure to alcohol and drugs -- a major contributor to crash risk -- is considerably higher than for teens.

"If you haven't gone through GDL, you're not gradually exposed to nighttime driving and typically not gradually exposed to driving with several passengers where you progressively learn to manage the occupant space while driving," Vaca said.

Vaca said that in addition to missing safety instruction, which results in more crashes and fatalities among vulnerable populations, some teens who delay licensure miss out on employment, education, and other opportunities.

One solution, Vaca said, can be found by looking to GDL policies in other countries, such as Australia and the United Kingdom, where GDL restrictions are applied to novice drivers of all ages before a full license is issued.

"Motor vehicle crashes are the leading cause of death for young people," Vaca said. "It's important that they get sufficient supervised practice driving as well as gradual exposure to a variety of driving conditions and learn how to safely navigate them."

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Insufficient sleep harms children's mental health

University of Houston study: Poor sleep at night 'spills over' into children's emotional lives

UNIVERSITY OF HOUSTON

IMAGE: POOR SLEEP HARMS CHILDREN'S MENTAL HEALTH AND EMOTIONAL STABILITY ACCORDING TO A NEW STUDY PUBLISHED BY UNIVERSITY OF HOUSTON PROFESSOR OF PSYCHOLOGY AND DIRECTOR OF THE SLEEP AND ANXIETY CENTER... view more 

CREDIT: UNIVERSITY OF HOUSTON

In a new study published in the Journal of Child Psychology and Psychiatry, Candice Alfano, University of Houston professor of psychology and director of the Sleep and Anxiety Center of Houston, reports the results from an innovative, experimental study showing inadequate nighttime sleep alters several aspects of children's emotional health.

Although plenty of correlational research links inadequate sleep with poor emotional health, experimental studies in children are rare. Alfano and her team studied 53 children ages 7-11 over more than a week. The children completed an in-lab emotional assessment twice, once after a night of healthy sleep and again after two nights where their sleep was restricted by several hours.

"After sleep restriction, we observed changes in the way children experience, regulate and express their emotions," reports Alfano. "But, somewhat to our surprise, the most significant alterations were found in response to positive rather than negative emotional stimuli."

The multi-method assessment had children view a range of pictures and movie clips eliciting both positive and negative emotions while the researchers recorded how children responded on multiple levels. In addition to subjective ratings of emotion, researchers collected respiratory sinus arrhythmias (a non-invasive index of cardiac-linked emotion regulation) and objective facial expressions. Alfano points out the novelty of these data. "Studies based on subjective reports of emotion are critically important, but they don't tell us much about the specific mechanisms through which insufficient sleep elevates children's psychiatric risk."

Alfano highlights the implications of her findings for understanding how poor sleep might "spill over" into children's everyday social and emotional lives. "The experience and expression of positive emotions are essential for children's friendships, healthy social interactions and effective coping. Our findings might explain why children who sleep less on average have more peer-related problems," she said.

Another important finding from the study is that the impact of sleep loss on emotion was not uniform across all children. Specifically, children with greater pre-existing anxiety symptoms showed the most dramatic alterations in emotional responding after sleep restriction.

According to Alfano, these results emphasize a potential need to assess and prioritize healthy sleep habits in emotionally vulnerable children.

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Breakthrough machine learning approach quickly produces higher-resolution climate data

DOE/NATIONAL RENEWABLE ENERGY LABORATORY

 Researchers at the U.S. Department of Energy's (DOE's) National Renewable Energy Laboratory (NREL) have developed a novel machine learning approach to quickly enhance the resolution of wind velocity data by 50 times and solar irradiance data by 25 times--an enhancement that has never been achieved before with climate data.

The researchers took an alternative approach by using adversarial training, in which the model produces physically realistic details by observing entire fields at a time, providing high-resolution climate data at a much faster rate. This approach will enable scientists to complete renewable energy studies in future climate scenarios faster and with more accuracy.

"To be able to enhance the spatial and temporal resolution of climate forecasts hugely impacts not only energy planning, but agriculture, transportation, and so much more," said Ryan King, a senior computational scientist at NREL who specializes in physics-informed deep learning.

King and NREL colleagues Karen Stengel, Andrew Glaws, and Dylan Hettinger authored a new article detailing their approach, titled "Adversarial super-resolution of climatological wind and solar data," which appears in the journal Proceedings of the National Academy of Sciences of the United States of America.

Accurate, high-resolution climate forecasts are important for predicting variations in wind, clouds, rain, and sea currents that fuel renewable energies. Short-term forecasts drive operational decision-making; medium-term weather forecasts guide scheduling and resource allocations; and long-term climate forecasts inform infrastructure planning and policymaking.

However, it is very difficult to preserve temporal and spatial quality in climate forecasts, according to King. The lack of high-resolution data for different scenarios has been a major challenge in energy resilience planning. Various machine learning techniques have emerged to enhance the coarse data through super resolution--the classic imaging process of sharpening a fuzzy image by adding pixels. But until now, no one had used adversarial training to super-resolve climate data.

"Adversarial training is the key to this breakthrough," said Glaws, an NREL postdoc who specializes in machine learning.

Adversarial training is a way of improving the performance of neural networks by having them compete with one another to generate new, more realistic data. The NREL researchers trained two types of neural networks in the model--one to recognize physical characteristics of high-resolution solar irradiance and wind velocity data and another to insert those characteristics into the coarse data. Over time, the networks produce more realistic data and improve at distinguishing between real and fake inputs. The NREL researchers were able to add 2,500 pixels for every original pixel.

"By using adversarial training--as opposed to the traditional numerical approach to climate forecasts, which can involve solving many physics equations--it saves computing time, data storage costs, and makes high-resolution climate data more accessible," said Stengel, an NREL graduate intern who specializes in machine learning.

This approach can be applied to a wide range of climate scenarios from regional to global scales, changing the paradigm for climate model forecasting.

NREL is the U.S. Department of Energy's primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by the Alliance for Sustainable Energy, LLC.

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Texas hurricanes: Fast like Ike or slow like Harvey?

Climate change will make fast-moving storms more likely in late 21st-century Texas
HOUSTON -- (July 7, 2020) -- Climate change will intensify winds that steer hurricanes north over Texas in the final 25 years of this century, increasing the odds for fast-moving storms like 2008's Ike compared with slow-movers like 2017's Harvey, according to new research.


The study published online July 3 in Nature Communications examined regional atmospheric wind patterns that are likely to exist over Texas from 2075-2100 as Earth's climate changes due to increased greenhouse emissions.

The research began in Houston as Harvey deluged the city with 30-40 inches of rain over five days. Rice University researchers riding out the storm began collaborating with colleagues from Columbia University's Lamont-Doherty Earth Observatory (LDEO) and Harvard University to explore whether climate change would increase the likelihood of slow-moving rainmakers like Harvey.

"We find that the probability of having strong northward steering winds will increase with climate change, meaning hurricanes over Texas will be more likely to move like Ike than Harvey," said study lead author Pedram Hassanzadeh of Rice.

Harvey caused an estimated $125 billion in damage, matching 2005's Katrina as the costliest hurricane in U.S. history. Ike was marked by coastal flooding and high winds that caused $38 billion damage across several states. It was the second-costliest U.S. hurricane at the time and has since moved to sixth. Ike struck Galveston around 2 a.m. Sept. 13, 2008, crossed Texas in less than one day and caused record power outages from Arkansas to Ohio on Sept. 14.

Hassanzadeh, a fluid dynamicist, atmospheric modeler and assistant professor of both mechanical engineering and Earth, environmental and planetary sciences, said the findings don't suggest that slow-moving storms like Harvey won't happen in late 21st century. Rather, they suggest that storms during the period will be more likely to be fast-moving than slow-moving. The study found the chances that a Texas hurricane will be fast-moving as opposed to slow-moving will rise by about 50% in the last quarter of the 21st century compared with the final quarter of the 20th century.

"These results are very interesting, given that a previous study that considered the Atlantic basin as a whole noticed a trend for slower-moving storms in the past 30 years," said study co-author Suzana Camargo, LDEO's Marie Tharp Lamont Research Professor. "By contrast, our study focused on changes at the end of the 21st century and shows that we need to consider much smaller regional scales, as their trends might differ from the average across much larger regions."

Hassanzadeh said the researchers used more than a dozen different computer models to produce several hundred simulations and found that "all of them agreed on an increase in northward steering winds over Texas."

Steering winds are strong currents in the lower 10 kilometers of the atmosphere that move hurricanes.

"It doesn't happen a lot, in studying the climate system, that you get such a robust regional signal in wind patterns," he said.

Harvey was the first hurricane Hassanzadeh experienced. He'd moved to Houston the previous year and was stunned by the slow-motion destruction that played out as bayous, creeks and rivers in and around the city topped their banks.

"I was sitting at home watching, just looking at the rain when (study co-author) Laurence (Yeung) emailed a bunch of us, asking 'What's going on? Why is this thing not moving?'" Hassanzadeh recalled. "That got things going. People started replying. That's the good thing about being surrounded by smart people. Laurence got us started, and things took off."

Yeung, an atmospheric chemist, Hassanzadeh and two other Rice professors on the original email, atmospheric scientist Dan Cohan and flooding expert Phil Bedient, won one of the first grants from Rice's Houston Engagement and Recovery Effort (HERE), a research fund Rice established in response to Harvey.

"Without that, we couldn't have done this work," Hassanzadeh said. The HERE grant allowed Rice co-author Ebrahim Nabizadeh, a graduate student in mechanical engineering, to work for several months, analyzing the first of hundreds of computer simulations based on large-scale climate models.

The day Harvey made landfall, Hassanzadeh also had reached out to Columbia's Chia-Ying Lee, an expert in both tropical storms and climate downscaling, procedures that use known information at large scales to make projections at local scales. Lee and Camargo used information from the large-scale simulations to make a regional model that simulated storms' tracks over Texas in a warming climate.

"One challenge of studying the impact of climate change on hurricanes at a regional level is the lack of data," said Lee, a Lamont Assistant Research Professor at LDEO. "At Columbia University, we have developed a downscaling model that uses physics-based statistics to connect large-scale atmospheric conditions to the formation, movement and intensity of hurricanes. The model's physical basis allowed us to account for the impact of climate change, and its statistical features allowed us to simulate a sufficient number of Texas storms."

Hassanzadeh said, "Once we found that robust signal, where all the models agreed, we thought, 'There should be a robust mechanism that's causing this.'"

He reached out to tropical climate dynamicist Ding Ma of Harvard to get another perspective.

"We were able to show that changes in two important processes were joining forces and resulting in the strong signal from the models," said Ma, a postdoctoral researcher in Earth and planetary sciences.

One of the processes was the Atlantic subtropical high, or Bermuda high, a semipermanent area of high pressure that forms over the Atlantic Ocean during the summer, and the other was the North American monsoon, an uptick in rainfall and thunderstorms over the southwestern U.S. and northwestern Mexico that typically occurs between July and September. Hassanzadeh said recent studies have shown that each of these are projected to change as Earth's climate warms.

"The subtropical high is a clockwise circulation to the east that is projected to intensify and shift westward, producing more northward winds over Texas," he said. "The North American monsoon, to the west, produces a clockwise circulation high in the troposphere. That circulation is expected to weaken, resulting in increased, high-level northward winds over Texas."

Hassanzadeh said the increased northward winds from both east and west "gives you a strong reinforcing effect over the whole troposphere, up to about 10 kilometers, over Texas. This has important implications for the movement of future Texas hurricanes."

Models showed that the effect extended into western Louisiana, but the picture became murkier as the researchers looked further east, he said.

"You don't have the robust signal like you do over Texas," Hassanzadeh said. "If you look at Florida, for instance, there's a lot of variation in the models. This shows how important it is to conduct studies that focus on climate impacts in specific regions. If we had looked at all of North America, for example, and tried to average over the whole region, we would have missed this localized mechanism over Texas."

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Bedient is the Herman Brown Professor of Engineering and department chair of civil and environmental engineering and director of Rice's Severe Storm Prediction, Education and Evacuation from Disasters Center. Cohan is an associate professor of civil and environmental engineering. Yeung is the Maurice Ewing Career Development Assistant Professor in Earth Systems Science in the Department of Earth, Environmental and Planetary Sciences.

The research was supported by the National Science Foundation (AGS-1921413), NASA (80NSSC17K0266), the Gulf Research Program of the National Academies of Sciences, Engineering and Medicine's Early-Career Research Fellowship Program, Rice's Houston Engagement and Recovery Effort Fund, Columbia's Center for Climate and Life Fellows Program, the National Oceanic and Atmospheric Administration (NA16OAR4310079, NA18OAR4310277) and the New York State Energy Research and Development Authority (NYSERDA 103862). Computational resources were provided by the National Science Foundation's Extreme Science and Engineering Discovery Environment (ATM170020), the National Center for Atmospheric Research's Computational and Information Systems Lab (URIC0004) and Rice's Center for Research Computing.

Links and resources:

The DOI of the Nature Communications paper is: 10.1038/s41467-020-17130-7

A copy of the paper is available at: https://doi.org/10.1038/s41467-020-17130-7

High-resolution IMAGES are available for download at:

https://news-network.rice.edu/news/files/2020/07/0703_TEXASSTORMS-harveyISS-lg.jpg

CAPTION: Hurricane Harvey as seen from the International Space Station on Aug. 28, 2017. (Photo courtesy of Randy Bresnik/NASA)

https://news-network.rice.edu/news/files/2020/07/0703_TEXASSTORMS-IkeRain-med.jpg

CAPTION: Map depicting total rainfall from 2008's Hurricane Ike. (Image by Hal Pierce/SSAI/NASA)

https://news-network.rice.edu/news/files/2020/07/0703_TEXASSTORMS-harveyrain-lg.jpg

CAPTION: Map depicting total rainfall from 2017's Hurricane Harvey. (Image courtesy of NOAA)

https://news-network.rice.edu/news/files/2020/07/0703_TEXASSTORMS-pedram-lg.jpg

CAPTION: Pedram Hassanzadeh

This release can be found online at news.rice.edu.

Follow Rice News and Media Relations via Twitter @RiceUNews.

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,962 undergraduates and 3,027 graduate students, Rice's undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 4 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance.

Early childhood education centers can boost parents' engagement at home

UNIVERSITY OF ARIZONA

 

COVID-19 has temporarily shuttered many early childhood education centers across the country, shifting full-time child care and teaching responsibilities largely to parents.

As some of those centers look toward reopening, they can play an important part in ensuring that parents continue to be engaged in their children's education at home, says University of Arizona researcher Melissa Barnett.

In a study conducted before the pandemic began, Barnett and her colleagues looked at the role that early childhood education centers play in encouraging parents to engage in educational activities with their children both at the centers and at home. The researchers also explored how parental engagement can help better prepare young children for kindergarten.

Their findings were recently published in Early Childhood Research Quarterly.

"There's been some research evidence that when parents of preschoolers are more engaged in early childhood education centers, their children may be more prepared for kindergarten. But it's not entirely clear why that's the case," said Barnett, lead study author and an associate professor of family studies and human development in the UArizona Norton School of Family and Consumer Sciences, housed in the College of Agriculture and Life Sciences.

"One of the goals of our study was to understand the extent to which parents perceive that early childhood educators are working with them and engaging them, and whether that is linked to school readiness," said Barnett, who also is director of the Norton School's Frances McClelland Institute for Children, Youth and Families.

Among the researchers' key findings:

When parents perceive that early childhood education centers do a good job of communicating with them and providing information about how their children are doing, they are more likely to engage in educational activities such as reading and singing with their children - both at the center and at home. And the more parents engage in educational activities at home, the better prepared their children are for kindergarten, in terms of language and early reading skills.

The more involved parents are in center activities - such as volunteering in classrooms, attending meetings or chaperoning field trips - the more educational activities they do with their children at home.

Although early childhood education centers appear to influence the quantity of at-home educational activities, they do not influence the quality of those activities. And the quality of at-home educational activities is one of the strongest predictors of a child's school readiness, influencing not only language and early reading skills but also early math skills.

The research is based on data from the Early Childhood Longitudinal Study - Birth Cohort, a nationally representative sample of 10,700 children who were born in the United States in 2001 were followed from birth to kindergarten. The researchers homed in on the 17% of those children who were enrolled in early childhood education centers at age 4.

Those children's parents rated a series of statements designed to measure how well they thought their early childhood education centers did at keeping them informed and involved. The parents also answered questions about how often they engaged in educational activities with their children, both at the center and at home.

The children completed assessments to measure their language, reading and early math skills prior to entering kindergarten.

"For children who are enrolled in early childhood education centers, what parents did at home was a good predictor of how well children were prepared for school, in terms of the quantity of what parents were doing and the quality of what they were doing," Barnett said. "We found that more engagement in the early childhood education centers was related to doing more at home, and that seemed to be especially true for lower-income households."

The researchers also observed parents and children engaging in learning activities and assessed the quality of those interactions based on how much cognitive stimulation they provided. They found that quality matters even more than quantity for school readiness.

"It's important that parents read with their kids and sing to their kids. But the quality of what parents are doing also is really critical and perhaps harder to change," Barnett said.

That's an area where early childhood education centers could make a difference in the future, she said.

"Parents who are able to engage and volunteer at those centers are getting the message that they need to read with their kids and sing songs with their kids, but they may not be getting messages about how best to do that," Barnett said.

Some best practices, she said, include thinking about ways to build activities around a child's unique interests and abilities, and making activities such as reading more meaningful by stopping to ask questions that help children relate stories to their own experiences.

Pandemic Could Impact Access

Unfortunately, Barnett said, many families don't have access to early childhood education centers and the support they provide, especially in lower-income areas, where, according to her findings, they might have the most impact. The problem could be made even worse by COVID-19, she said, as some centers hit hard financially may be forced to close permanently.

"We know that many families in many communities didn't have access to high-quality early childhood education, even before the pandemic, and it's become an increasingly significant problem as centers have closed and may need to remain closed," she said. "In part, our findings point to the value of those opportunities for lower-income parents to be involved in early childhood education centers, so this potentially could even further increase what we see as a socioeconomic gap in school readiness."

For now, with many parents of all socioeconomic backgrounds at home with their kids, Barnett stresses the importance of focusing on quality activities as much as possible.

"This may be an especially challenging time to do that, as parents are juggling multiple potential stressors and time crunches," she said, "but those home learning activities really are important to prepare children for school."

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