Tuesday, July 07, 2020

Flu in early life determines our susceptibility to future infections

New findings suggest early exposure to the flu affects how likely we are to acquire future infections and may also impact vaccine effectiveness
ELIFE
Early infections of influenza A can help predict how the virus will affect people across different ages in the future and could impact the effectiveness of flu vaccines, says a new study published today in eLife.
The findings may help improve estimates of both the age-specific risk of acquiring seasonal influenza infections and vaccine effectiveness in similarly vaccinated populations.
Seasonal influenza is an acute respiratory infection caused by influenza viruses that occur across the world. It causes approximately 100,000-600,000 hospitalisations and 5,000-27,000 deaths per year in the US alone. There are three types of seasonal influenza viruses in humans: A, B and C, although C is much less common. Influenza A viruses are further classified into subtypes, with the A(H1N1) and A(H3N2) subtypes currently circulating in humans. A(H1N1) is also written as A(H1N1)pdm09 as it caused the 2009 pandemic and replaced the A(H1N1) virus which had circulated before that year.*
The rapid evolution of seasonal influenza that allows it to escape preexisting immunity adds to the relatively high incidence of infections, including in previously infected older children and adults. But how susceptibility arises and changes over time in human populations has been difficult to quantify.
"Since the risk of influenza infection in a given age group changes over time, factors other than age may affect our susceptibility to infection," says first author Philip Arevalo, a postdoctoral researcher in senior author Sarah Cobey's lab, Department of Ecology and Evolution, University of Chicago, US. "We wanted to see whether these differences can be explained in part by the protection gained from childhood flu infection, which has lasting impacts on the immune response to future infections and the protection against new influenza A subtypes."
To measure the effect of early exposures to seasonal influenza on risk and vaccine effectiveness, Arevalo and his team applied statistical models to flu cases identified through seasonal studies of vaccine effectiveness from the 2007-2008 to 2017-2018 seasons in the Marshfield Epidemiologic Study Area (MESA) in Marshfield, Wisconsin, US. Each flu season, individuals in a defined community group were recruited and tested for flu when seeking outpatient care for acute respiratory infection. Those eligible for the study were individuals older than six months of age living in MESA and who received routine care from the Marshfield Clinic.
Despite the extensive evolution in influenza A subtypes H1N1 and H3N2 over the study period, the team's model showed that early infection reduces the risk of people needing to seek medical attention for infections with the same subtype later in life. This effect is stronger for H1N1 compared to H3N2. The model also revealed that the effectiveness of flu vaccines varies with both age and birth year, suggesting that this effectiveness also depends on early exposure.
"We hope the findings from our study will improve our understanding of influenza epidemiology and the low and variable effectiveness of the seasonal flu vaccine," concludes senior author Sarah Cobey, Principal Investigator at the Department of Ecology and Evolution, University of Chicago. "This would lead to better forecasting and vaccination strategies to help combat future flu seasons."
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Reference
The paper 'Earliest infections predict the age distribution of seasonal influenza A cases', can be freely accessed online at https://doi.org/10.7554/eLife.50060. Contents, including text, figures and data, are free to reuse under a CC BY 4.0 license.
*Information provided by the World Health Organization at https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal).
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Study reveals many great lakes state parks impacted by record-high water levels

The research was presented at the 2020 Great Lakes Virtual Conference, which is hosted by the International Association of Great Lakes Research.
UNIVERSITY OF TOLEDO
IMAGE
IMAGE: GOLDEN HILL STATE PARK IN 2019 view more 
CREDIT: PATRICK LAWRENCE
Every summer millions of people visit parks and protected areas along the shorelines of the Great Lakes to camp, hike, swim and explore nature's beauty.
While COVID-19 has impacted staffing, operations and budgets at the parks, tourists this year also may notice changes if recent record-high water levels persist on Lake Huron, Lake Ontario, Lake Michigan, Lake Erie and Lake Superior.
A new study by a graduate student at The University of Toledo zeroes in on how coastal flooding and erosion in 2019 damaged park facilities and roads and interrupted visitor experiences, as well as examines the financial cost of the high water levels.
The research presented at the 2020 Great Lakes Virtual Conference, which is hosted by the International Association of Great Lakes Research, was completed by Eric Kostecky, a graduate student earning his master's degree in geography, as part of a course in environmental planning he took last fall while completing his undergraduate degree in geography and planning.
"A humbling statistic is that 75% of the parks indicated that continued higher lake levels in 2020 and beyond would further impact park operations and infrastructure," Kostecky said. "Future management actions would be to improve parking lots and roads and to move hiking trails, campgrounds and public access locations."
To gather information, Kostecky surveyed 50 parks along the Great Lakes, both federal and state parks in the United States and provincial parks in Canada. Twenty-nine responded.
"Even though Great Lakes parks and protected areas have experienced impacts from shoreline erosion and flooding during previous high water-level events in 1972-73 and 1985-86, this study is the first comprehensive attempt to catalogue those impacts," said Dr. Patrick Lawrence, professor and chair of the UToledo Department of Geography and Planning and Kostecky's faculty advisor.
The study shows 50% of the responding parks were impacted by both shoreline erosion and flooding, with the most common type of damage being to boat launches and building structures that were flooded, and roads near dunes washed away by waves.
Total cost of damage for 55% of the parks was $50,000 or less.
As a result of the damage, parks implemented a variety of changes for public safety last year: sections of the park were closed, select park operations were canceled, and some visitor education programs were suspended.
Great Lakes water levels peaked in July 2019, with increases varying between 14 and 31 inches above their long-term averages; Lake Superior was at 14 inches above its average, while Lake Michigan, Lake Huron, Lake Erie and Lake Ontario were at 31 inches above average, Lawrence said.
"The water levels in the Great Lakes fluctuate, but they don't fluctuate rapidly, so it's hard to say if we're still in the upswing or on the downswing," Kostecky said. "We won't know if we're continuing to rise or if waters have started to recede for the next couple of years."
The Great Lakes shoreline stretches 10,000 miles around eight U.S. states and Canada.
"Many parks and protected areas in the Great Lakes have struggled with the economic costs and interruptions of their operations, including services and programs for their visitors, and are concerned that as this period of high water levels continues this summer, they will face ongoing challenges in delivering the levels of public access and services to their visitors so eager to explore the parks and enjoy the nature and environment provided by these special spaces," Lawrence said.
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Tree rings show unprecedented rise in extreme weather in South America

Newly comprehensive continental drought atlas covers last 600 years
EARTH INSTITUTE AT COLUMBIA UNIVERSITY
IMAGE
IMAGE: ARAUCARIA ARAUCANA TREES IN NORTHERN PATAGONIA, ARGENTINA, SOME OF WHICH WERE USED IN THE STUDY. SOME TREES CAN LIVE 1,000 YEARS. view more 
CREDIT: RICARDO VILLALBA, ARGENTINE INSTITUTE OF SNOW, GLACIER AND ENVIRONMENTAL SCIENCES, AT THE NATIONAL RESEARCH COUNCIL FOR SCIENCE AND TECHNOLOGY
Scientists have filled a gaping hole in the world's climate records by reconstructing 600 years of soil-moisture swings across southern and central South America. Along with documenting the mechanisms behind natural changes, the new South American Drought Atlas reveals that unprecedented widespread, intense droughts and unusually wet periods have been on the rise since the mid-20th century. It suggests that the increased volatility could be due in part to global warming, along with earlier pollution of the atmosphere by ozone-depleting chemicals. The atlas was published this week in the journal Proceedings of the National Academy of Sciences.
Recent droughts have battered agriculture in wide areas of the continent, trends the study calls "alarming." Lead author Mariano Morales of the Argentine Institute of Snow, Glacier and Environmental Sciences at the National Research Council for Science and Technology, said, "Increasingly extreme hydroclimate events are consistent with the effects of human activities, but the atlas alone does not provide evidence of how much of the observed changes are due to natural climate variability versus human-induced warming." The new long-term record "highlights the acute vulnerability of South America to extreme climate events," he said.
Coauthor Edward Cook, head of the Tree Ring Lab at Columbia University's Lamont-Doherty Earth Observatory, said, "We don't want to jump off the cliff and say this is all climate change. There is a lot of natural variability that could mimic human-induced climate change." However, he said, armed with the new 600-year record, scientists are better equipped to sort things out.
The South American Drought Atlas is the latest in a series of drought atlases assembled by Cook and colleagues, covering many centuries of year-by-year climate conditions in North America; Asia; Europe and the Mediterranean; and New Zealand and eastern Australia. Subsequent studies building on the atlases have yielded new insights into how droughts may have adversely affected past civilizations, and the increasingly apparent role of human-induced warming on modern climate. Most recently, followup analyses of North America have suggested that warming is driving what may be the worst-ever known drought in the U.S. West.
The new atlas covers Argentina, Chile, Uruguay, Paraguay, most of Bolivia, and southern Brazil and Peru. It is the result of years of field collections of thousands of tree-ring records, and subsequent analyses by South American researchers, along with colleagues in Europe, Canada, Russia and the United States. Ring widths generally reflect yearly changes in soil moisture, and the researchers showed that collected rings correlate well with droughts and floods recorded starting in the early Spanish colonial period, as well as with modern instrumental measurements. This gave them confidence to extend the soil-moisture reconstruction back before written records.
The authors say that periodic natural shifts in precipitation are driven by complex, interlocking patterns of atmospheric circulation on land and at sea. One key factor: low-level westerly winds that blow moisture onto the continent from the Pacific. These are controlled in part by periodic cyclic changes in sea-surface temperatures over both the Pacific and the Atlantic, which can bring both droughts and wet periods. The authors say greenhouse-gas-driven shifts in these patterns appear linked to a still continuing 10-year drought over central Chile and western Argentina that has caused severe water shortages, along with heavier than normal rains in eastern regions.
Precipitation is also controlled in part by the Southern Annular Mode, a belt of westerly winds that circles Antarctica. This belt periodically contracts southward or expands northward, and when it contracts, it weakens the westerly winds that bring rain to South America. In recent decades, it has been stuck in the south -- largely a result of ozone-depleting chemicals used in 20th-century refrigerants that destroyed atmospheric ozone over Antarctica, scientists believe. The chemicals were banned in the 1980s, but their effects have persisted.
The third major factor is the so-called Hadley cell, a global phenomenon that lofts warm, moist air from near the equator and sends it further north and south, dropping precipitation as it goes. The air settles near the surface at predictable latitudes, by which time the moisture has been largely wrung out; this creates the permanently dry zones of the subtropics, including those in South America. During recent decades, the Hadley cell has expanded towards the poles, likely in response to human-induced climate changes; this has shifted rainfall patterns and broadened the subtropical dry zones, especially in the Southern Hemisphere.
The atlas indicates that there has been a steady increase in the frequency of widespread droughts since 1930, with the highest return times, about 10 years, occurring since the 1960s. Severe water shortages have affected central Chile and western Argentina from 1968-1969, 1976-1977, and 1996-1997. Currently, the drylands of central Chile and western Argentina are locked in one of the most severe decade-long droughts in the record. In some areas, up to two-thirds of some cereal and vegetable crops have been lost in some years. This threatens "the potential collapse of food systems," says Morales.
At the same time, southeastern parts of the continent are seeing heavier than normal rains. Walter Baethgen, who leads Latin American agricultural research for Columbia University's International Research Institute for Climate and Society, says his own studies show that the La Plata basin of Uruguay has seen more frequent extremely wet summers since 1970, with corresponding increases in crop and livestock production. But the frequency of very dry summers has remained the same, which translates to bigger losses of expected yields when they do come along, he said.
"Everything is consistent with the idea that you'll be intensifying both wet and dry events with global warming," said Jason Smerdon, a climate scientist at Lamont-Doherty and a coauthor of the study.
Using newly developed tree-ring records from Peru, Brazil, Bolivia and Colombia, the group is now working to expand the atlas to cover the entire continent, and extend the climate reconstruction back 1,000 years or more, said Morales.
The authors wish to dedicate the study to the memory of the late MarĂ­a del Rosario Prieto, their coauthor, and active promoter of environmental history studies in South America.
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The paper, 'Six hundred years of South American tree rings reveal an increase in severe hydroclimatic events since mid-20th century,' can be obtained by contacting pnasnews@nas.edu or 202-334-1310
Scientist contacts:
More information: Kevin Krajick, Senior editor, science news, The Earth Institute
Lamont-Doherty Earth Observatory is Columbia University's home for Earth science research. Its scientists develop fundamental knowledge about the origin, evolution and future of the natural world, from the planet's deepest interior to the outer reaches of its atmosphere, on every continent and in every ocean, providing a rational basis for the difficult choices facing humanity. http://www.ldeo.columbia.edu | @LamontEarth
The Earth Institute, Columbia University mobilizes the sciences, education and public policy to achieve a sustainable earth. http://www.earth.columbia.edu.

Long-acting injectable form of HIV prevention outperforms daily pill in NIH study


Both methods highly effective at preventing HIV among men who have sex with men and transgender women

NIH/NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES

WHAT: A pre-exposure prophylaxis (PrEP) regimen containing an investigational long-acting form of the HIV drug cabotegravir injected once every 8 weeks was more effective than daily oral Truvada at preventing HIV acquisition among cisgender men who have sex with men and transgender women who have sex with men in a clinical trial sponsored by the National Institutes of Health. While both methods were highly effective for HIV prevention in the study population, the final data analysis indicated that cabotegravir had a superior protective effect. Findings from the Phase 2b/3 study, called HPTN 083, will be discussed in an online press conference and oral presentations during the 23rd International AIDS Conference (AIDS 2020: Virtual).
The only currently licensed PrEP medications--daily oral pills containing the HIV drugs tenofovir and emtricitabine--are highly effective at preventing HIV when taken as prescribed. However, taking a pill daily can be challenging. A long-acting form of PrEP could offer a less frequent, more discreet option that may be more desirable for some people. HPTN 083 and an ongoing companion study called HPTN 084, which is evaluating long-acting injectable cabotegravir for HIV prevention in cisgender women in sub-Saharan Africa, are sponsored by NIH's National Institute of Allergy and Infectious Diseases (NIAID).
In May 2020, a planned interim review of HPTN 083 data indicated a high level of efficacy for long-acting injectable cabotegravir among cisgender men and transgender women who have sex with men. The results reported today are based on a more extensive analysis of interim data from 4,566 study participants.
Overall, the rate of HIV acquisition in the participants was low. Among the 52 participants who acquired HIV, 13 were in the study group who received the cabotegravir-based PrEP regimen plus placebo daily oral tablets, and 39 were in the group who received daily oral Truvada plus placebo injections. This translated to an HIV incidence rate of 0.41% (95% confidence interval [CI] 0.22%-0.69%) in the cabotegravir group and 1.22% (95% CI 0.87%-1.67%) in the Truvada group--indicating 66% lower incidence in the cabotegravir group. Detailed analysis of these data indicated that the superior efficacy of cabotegravir was statistically significant.
Both products were safe and generally well-tolerated. Participants in the cabotegravir group were more likely to experience fever and pain or tenderness at the injection site compared to those in the Truvada group, who received placebo injections. Those in the Truvada group were more likely to report nausea. Most participants in the cabotegravir group received their injections as scheduled, with only 46 people (2.2%) discontinuing injections. Adherence to daily Truvada was also high, with 87% of a subset of 372 participants who provided blood samples having some detectable concentrations of the drug. Study investigators are continuing to follow the HPTN 083 study participants and to gather and analyze additional data on the long-term safety of injectable cabotegravir for HIV prevention.
NIAID collaborates on HPTN 083 with ViiV Healthcare, Gilead Sciences, Inc., and the NIH-funded HIV Prevention Trials Network (HPTN). NIAID and ViiV Healthcare co-fund the trial, which is conducted by the HPTN. ViiV Healthcare and Gilead Sciences, Inc., provide study medications. Three other NIH institutes also collaborate on HPTN 083: the National Institute of Mental Health, the National Institute on Drug Abuse, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development. More information about HPTN 083 is available on ClinicalTrials.gov under identifier NCT02720094.
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PRESENTATIONS: R. Landovitz et al. HPTN 083 interim results: pre-exposure prophylaxis containing long-acting injectable cabotegravir is safe and highly effective for cisgender men and transgender women who have sex with men. Oral presentation at the 23rd International AIDS Conference (AIDS 2020: Virtual), July 8, 5 p.m. ET
B. Grinsztejn et al. HPTN 083 interim results: efficacy of pre-exposure prophylaxis containing long-acting injectable cabotegravir is maintained across regions and key populations. Oral presentation at the 23rd International AIDS Conference (AIDS 2020: Virtual), July 9, 4 a.m. ET
WHO: Anthony S. Fauci, M.D., director of NIAID, and Carl W. Dieffenbach, Ph.D., director of NIAID's Division of AIDS, are available to comment.
CONTACT: To schedule interviews, please contact Hillary Hoffman, (301) 402-1663, niaidnews@niaid.nih.gov.
NIAID conducts and supports research--at NIH, throughout the United States, and worldwide--to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID website.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov/.

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: 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
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
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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
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.