Scientists unravel mystery of photosynthesis

Sunlight and leaves (stock image).

Plants have been harnessing the sun's energy for hundreds of millions of years.

Algae and photosynthetic bacteria have been doing the same for even longer, all with remarkable efficiency and resiliency.

It's no wonder, then, that scientists have long sought to understand exactly how they do this, hoping to use this knowledge to improve human-made devices such as solar panels and sensors.

Scientists from the U.S. Department of Energy's (DOE) Argonne National Laboratory, working closely with collaborators at Washington University in St. Louis, recently solved a critical part of this age-old mystery, homing in on the initial, ultrafast events through which photosynthetic proteins capture light and use it to initiate a series of electron transfer reactions.

"In order to understand how biology fuels all of its engrained activities, you must understand electron transfer," said Argonne biophysicist Philip Laible. "The movement of electrons is crucial: it's how work is accomplished inside a cell."

In photosynthetic organisms, these processes begin with the absorption of a photon of light by pigments localized in proteins.

Each photon propels an electron across a membrane located inside specialized compartments within the cell.

"The separation of charge across a membrane -- and stabilization of it -- is critical as it generates energy that fuels cell growth," said Argonne biochemist Deborah Hanson.

The Argonne and Washington University research team has gained valuable insight on the initial steps in this process: the electron's journey.

Nearly 35 years ago, when the first structure of these types of complexes was unveiled, scientists were surprised to discover that after the absorption of light, the electron transfer processes faced a dilemma: there are two possible pathways for the electron to travel.

In nature, plants, algae and photosynthetic bacteria use just one of them -- and scientists had no idea why.

What they did know was that the propulsion of the electron across the membrane -- effectively harvesting the energy of the photon -- required multiple steps.

Argonne and Washington University scientists have managed to interfere with each one of them to change the electron's trajectory.

"We've been on this trail for more than three decades, and it is a great accomplishment that opens up many opportunities," said Dewey Holten, a chemist at Washington University.

The scientists' recent article, "Switching sides -- Reengineered primary charge separation in the bacterial photosynthetic reaction center," published in the Proceedings of the National Academy of Sciences, shows how they discovered an engineered version of this protein complex that switched the utilization of the pathways, enabling the one that was inactive while disabling the other.

"It is remarkable that we have managed to switch the direction of initial electron transfer," said Christine Kirmaier, Washington University chemist and project leader. "In nature, the electron chose one path 100 percent of the time. But through our efforts, we have been able to make the electron switch to an alternate path 90 percent of the time. These discoveries pose exciting questions for future research."

As a result of their efforts, the scientists are now closer than ever to being able to design electron transfer systems in which they can send an electron down a pathway of their choosing.

"This is important because we are gaining the ability to harness the flow of energy to understand design principles that will lead to new applications of abiotic systems," Laible said. "This would allow us to greatly improve the efficiency of many solar-powered devices, potentially making them far smaller. We have a tremendous opportunity here to open up completely new disciplines of light-driven biochemical reactions, ones that haven't been envisioned by nature. If we can do that, that's huge."

---

Story Source:

Materials provided by DOE/Argonne National Laboratory. Original written by Jo Napolitano. Note: Content may be edited for style and length.

First childhood flu helps explain why virus hits some people harder than others

Taking temperature of child (stock image).

Why are some people better able to fight off the flu than others? Part of the answer, according to a new study, is related to the first flu strain we encounter in childhood.

Scientists from UCLA and the University of Arizona have found that people's ability to fight off the flu virus is determined not only by the subtypes of flu they have had throughout their lives, but also by the sequence in which they are been infected by the viruses. Their study is published in the open-access journal PLoS Pathogens.

The research offers an explanation for why some people fare much worse than others when infected with the same strain of the flu virus, and the findings could help inform strategies for minimizing the effects of the seasonal flu.

In addition, UCLA scientists, including Professor James Lloyd-Smith, who also was a senior author of the PLoS Pathogens research, recently completed a study that analyzes travel-related screening for the new novel coronavirus 2019-nCoV.

The researchers report that screening travelers is not very effective for the 2019 coronavirus -- that it will catch less than half of infected travelers, on average -- and that most infected travelers are undetectable, meaning that they have no symptoms yet, and are unaware that they have been exposed. So stopping the spread of the virus is not a matter of just enhancing screening methods at airports and other travel hubs.

"This puts the onus on government officials and public health officials to follow up with travelers after they arrive, to isolate them and trace their contacts if they get sick later," said Lloyd-Smith, a UCLA professor of ecology and evolutionary biology. Many governments have started to impose quarantines, or even travel bans, as they realize that screening is not sufficient to stop the spread of the coronavirus.

One major concern, Lloyd-Smith said, is that other countries, especially developing nations, lack the infrastructure and resources for those measures, and are therefore vulnerable to importing the disease.

"Much of the public health world is very concerned about the virus being introduced into Africa or India, where large populations exist do not have access to advanced medical care," he said.

The researchers, including scientists from the University of Chicago and the London School of Tropical Hygiene and Medicine, have developed a free online app where people can calculate the effectiveness of travel screening based on a range of parameters.

Solving a decades-old question

The PLoS Pathogens study may help solve a problem that had for decades vexed scientists and health care professionals: why the same strain of the flu virus affects people with various degrees of severity.

A team that included some of the same UCLA and Arizona scientists reported in 2016 that exposure to influenza viruses during childhood gives people partial protection for the rest of their lives against distantly related influenza viruses. Biologists call the idea that past exposure to the flu virus determines a person's future response to infections "immunological imprinting."

The 2016 research helped overturn a commonly held belief that previous exposure to a flu virus conferred little or no immunological protection against strains that can jump from animals into humans, such as those causing the strains known as swine flu or bird flu. Those strains, which have caused hundreds of spillover cases of severe illness and death in humans, are of global concern because they could gain mutations that allow them to readily jump not only from animal populations to humans, but also to spread rapidly from person to person.

In the new study, the researchers investigated whether immunological imprinting could explain people's response to flu strains already circulating in the human population and to what extent it could account for observed discrepancies in how severely the seasonal flu affects people in different age groups.

To track how different strains of the flu virus affect people at different ages, the team analyzed health records that the Arizona Department of Health Services obtains from hospitals and private physicians.

Two subtypes of influenza virus, H3N2 and H1N1, have been responsible for seasonal outbreaks of the flu over the past several decades. H3N2 causes the majority of severe cases in high-risk elderly people and the majority of deaths from the flu. H1N1 is more likely to affect young and middle-aged adults, and causes fewer deaths.

The health record data revealed a pattern: People first exposed to the less severe strain, H1N1, during childhood were less likely to end up hospitalized if they encountered H1N1 again later in life than people who were first exposed to H3N2. And people first exposed to H3N2 received extra protection against H3N2 later in life.

The researchers also analyzed the evolutionary relationships between the flu strains. H1N1 and H3N2, they learned, belong to two separate branches on the influenza "family tree," said James Lloyd-Smith, a UCLA professor of ecology and evolutionary biology and one of the study's senior authors. While infection with one does result in the immune system being better prepared to fight a future infection from the other, protection against future infections is much stronger when one is exposed to strains from the same group one has battled before, he said.

The records also revealed another pattern: People whose first childhood exposure was to H2N2, a close cousin of H1N1, did not have a protective advantage when they later encountered H1N1. That phenomenon was much more difficult to explain, because the two subtypes are in the same group, and the researchers' earlier work showed that exposure to one can, in some cases, grant considerable protection against the other.

"Our immune system often struggles to recognize and defend against closely related strains of seasonal flu, even though these are essentially the genetic sisters and brothers of strains that circulated just a few years ago," said lead author Katelyn Gostic, who was a UCLA doctoral student in Lloyd-Smith's laboratory when the study was conducted and is now a postdoctoral fellow at the University of Chicago. "This is perplexing because our research on bird flu shows that deep in our immune memory, we have some ability to recognize and defend against the distantly related, genetic third cousins of the strains we saw as children.

"We hope that by studying differences in immunity against bird flus -- where our immune system shows a natural ability to deploy broadly effective protection -- and against seasonal flus -- where our immune system seems to have bigger blind spots -- we can uncover clues useful to universal influenza vaccine development."

Around the world, influenza remains a major killer. The past two flu seasons have been more severe than expected, said Michael Worobey, a co-author of the study and head of the University of Arizona's department of ecology and evolutionary biology. In the 2017-18 season, 80,000 people died in the U.S., more than in the swine flu pandemic of 2009, he said.

People who had their first bout of flu as children in 1955 -- when the H1N1 was circulating but the H3N2 virus was not -- were much more likely to be hospitalized with an H3N2 infection than an H1N1 infection last year, when both strains were circulating, Worobey said.

"The second subtype you're exposed to is not able to create an immune response that is as protective and durable as the first," he said.

The researchers hope that their findings could help predict which age groups might be severely affected during future flu seasons based on the subtype circulating. That information could also help health officials prepare their response, including decisions about who should receive certain vaccines that are only available in limited quantities.

The research was funded by the National Institutes of Health, the National Science Foundation, DARPA and the David and Lucile Packard Foundation. In 2018, the NIH's National Institute of Allergy and Infectious Diseases announced a strategic plan to develop a universal flu vaccine.

The study's co-authors are Rebecca Bridge of the Arizona Department of Health Services and Cecile Viboud of the Fogarty International Center at the NIH.

---

Story Source:

Materials provided by University of California - Los Angeles. Original written by Stuart Wolpert and Daniel Stolte. Note: Content may be edited for style and length.

Pluto's icy heart makes winds blow

Pluto (stock image).

A "beating heart" of frozen nitrogen controls Pluto's winds and may give rise to features on its surface, according to a new study.

Pluto's famous heart-shaped structure, named Tombaugh Regio, quickly became famous after NASA's New Horizons mission captured footage of the dwarf planet in 2015 and revealed it isn't the barren world scientists thought it was.

Now, new research shows Pluto's renowned nitrogen heart rules its atmospheric circulation. Uncovering how Pluto's atmosphere behaves provides scientists with another place to compare to our own planet. Such findings can pinpoint both similar and distinctive features between Earth and a dwarf planet billions of miles away.

Nitrogen gas -- an element also found in air on Earth -- comprises most of Pluto's thin atmosphere, along with small amounts of carbon monoxide and the greenhouse gas methane. Frozen nitrogen also covers part of Pluto's surface in the shape of a heart. During the day, a thin layer of this nitrogen ice warms and turns into vapor. At night, the vapor condenses and once again forms ice. Each sequence is like a heartbeat, pumping nitrogen winds around the dwarf planet.

New research in AGU's Journal of Geophysical Research: Planets suggests this cycle pushes Pluto's atmosphere to circulate in the opposite direction of its spin -- a unique phenomenon called retro-rotation. As air whips close to the surface, it transports heat, grains of ice and haze particles to create dark wind streaks and plains across the north and northwestern regions.

"This highlights the fact that Pluto's atmosphere and winds -- even if the density of the atmosphere is very low -- can impact the surface," said Tanguy Bertrand, an astrophysicist and planetary scientist at NASA's Ames Research Center in California and the study's lead author.

Most of Pluto's nitrogen ice is confined to Tombaugh Regio. Its left "lobe" is a 1,000-kilometer (620-mile) ice sheet located in a 3-kilometer (1.9-mile) deep basin named Sputnik Planitia -- an area that holds most of the dwarf planet's nitrogen ice because of its low elevation. The heart's right "lobe" is comprised of highlands and nitrogen-rich glaciers that extend into the basin.

"Before New Horizons, everyone thought Pluto was going to be a netball -- completely flat, almost no diversity," Bertrand said. "But it's completely different. It has a lot of different landscapes and we are trying to understand what's going on there."

Western winds

Bertrand and his colleagues set out to determine how circulating air -- which is 100,000 times thinner than that of Earth's -- might shape features on the surface. The team pulled data from New Horizons' 2015 flyby to depict Pluto's topography and its blankets of nitrogen ice. They then simulated the nitrogen cycle with a weather forecast model and assessed how winds blew across the surface.

The group discovered Pluto's winds above 4 kilometers (2.5 miles) blow to the west -- the opposite direction from the dwarf planet's eastern spin -- in a retro-rotation during most of its year. As nitrogen within Tombaugh Regio vaporizes in the north and becomes ice in the south, its movement triggers westward winds, according to the new study. No other place in the solar system has such an atmosphere, except perhaps Neptune's moon Triton.

The researchers also found a strong current of fast-moving, near-surface air along the western boundary of the Sputnik Planitia basin. The airflow is like wind patterns on Earth, such as the Kuroshio along the eastern edge of Asia. Atmospheric nitrogen condensing into ice drives this wind pattern, according to the new findings. Sputnik Planitia's high cliffs trap the cold air inside the basin, where it circulates and becomes stronger as it passes through the western region.

The intense western boundary current's existence excited Candice Hansen-Koharcheck, a planetary scientist with the Planetary Science Institute in Tucson, Arizona who wasn't involved with the new study.

"It's very much the kind of thing that's due to the topography or specifics of the setting," she said. "I'm impressed that Pluto's models have advanced to the point that you can talk about regional weather."

On the broader scale, Hansen-Koharcheck thought the new study was intriguing. "This whole concept of Pluto's beating heart is a wonderful way of thinking about it," she added.

These wind patterns stemming from Pluto's nitrogen heart may explain why it hosts dark plains and wind streaks to the west of Sputnik Planitia. Winds could transport heat -- which would warm the surface -- or could erode and darken the ice by transporting and depositing haze particles. If winds on the dwarf planet swirled in a different direction, its landscapes might look completely different.

"Sputnik Planitia may be as important for Pluto's climate as the ocean is for Earth's climate," Bertrand said. "If you remove Sputnik Planitia -- if you remove the heart of Pluto -- you won't have the same circulation," he added.

The new findings allow researchers to explore an exotic world's atmosphere and compare what they discover with what they know about Earth. The new study also shines light on an object 6 billion kilometers (3.7 billion miles) away from the sun, with a heart that captivated audiences around the globe.

"Pluto has some mystery for everybody," Bertrand said.

---

Story Source:

Materials provided by American Geophysical Union. Note: Content may be edited for style and length.

Scientists find record warm water in Antarctica, pointing to cause behind troubling glacier melt

Antarctica illustration (stock image).

A team of scientists has observed, for the first time, the presence of warm water at a vital point underneath a glacier in Antarctica -- an alarming discovery that points to the cause behind the gradual melting of this ice shelf while also raising concerns about sea-level rise around the globe.

"Warm waters in this part of the world, as remote as they may seem, should serve as a warning to all of us about the potential dire changes to the planet brought about by climate change," explains David Holland, director of New York University's Environmental Fluid Dynamics Laboratory and NYU Abu Dhabi's Center for Global Sea Level Change, which conducted the research. "If these waters are causing glacier melt in Antarctica, resulting changes in sea level would be felt in more inhabited parts of the world."

The recorded warm waters -- more than two degrees above freezing -- flow beneath the Thwaites Glacier, which is part of the Western Antarctic Ice Sheet. The discovery was made at the glacier's grounding zone -- the place at which the ice transitions between resting fully on bedrock and floating on the ocean as an ice shelf and which is key to the overall rate of retreat of a glacier.

Thwaites' demise alone could have significant impact globally.

It would drain a mass of water that is roughly the size of Great Britain or the state of Florida and currently accounts for approximately 4 percent of global sea-level rise. Some scientists see Thwaites as the most vulnerable and most significant glacier in the world in terms of future global sea-level rise -- its collapse would raise global sea levels by nearly one meter, perhaps overwhelming existing populated areas.

While the glacier's recession has been observed over the past decade, the causes behind this change had previously not been determined.

"The fact that such warm water was just now recorded by our team along a section of Thwaites grounding zone where we have known the glacier is melting suggests that it may be undergoing an unstoppable retreat that has huge implications for global sea level rise," notes Holland, a professor at NYU's Courant Institute of Mathematical Sciences.

The scientists' measurements were made in early January, after the research team created a 600-meter deep and 35-centimeter wide access hole and deployed an ocean-sensing device to measure the waters moving below the glacier's surface. This device gauges the turbulence of the water as well as other properties such as temperature. The result of turbulence is the mixing of fresh meltwater from the glacier and salty water from the ocean.

It marks the first time that ocean activity beneath the Thwaites Glacier has been accessed through a bore hole and that a scientific instrument measuring underlying ocean turbulence and mixing has been deployed. The hole was opened on January 8 and 9 and the waters beneath the glacier measured January 10 and 11.

Aurora Basinski, an NYU graduate student who made the turbulence measurement, said, "From our observations into the ocean cavity at the grounding zone we observed not only the presence of warm water, but also its turbulence level and thus its efficiency to melt the ice shelf base."

Another researcher, Keith Nicholls, a scientist with the British Antarctic Survey, added, "This is an important result as this is the first time turbulent dissipation measurements have been made in the critical grounding zone of the West Antarctic Ice Sheet."

This research was supported by a $2.1 million, five-year grant from the National Science Foundation (PLR-1739003). The grant is part of the International Thwaites Glacier Collaboration (ITGC), headed by the United Kingdom's Natural Environment Research Council and the National Science Foundation, which has been deploying scientists to gather the data needed to understand whether the glacier's collapse could begin in the next few decades or centuries. Other members of the field team included researchers from Penn State, Georgia Tech, and the British Antarctic Survey.

For more about the project, please visit: https://thwaitesglacier.org/projects/melt

---

Story Source:

Materials provided by New York University. Note: Content may be edited for style and length.

Newest solar telescope produces first images

The Daniel K. Inouye Solar Telescope has produced the highest resolution image of the sun's surface ever taken. In this picture, taken at 789 nanometers (nm), we can see features as small as 30km (18 miles) in size for the first time ever. The image shows a pattern of turbulent, 'boiling' gas that covers the entire sun. The cell-like structures -- each about the size of Texas -- are the signature of violent motions that transport heat from the inside of the sun to its surface. Hot solar material (plasma) rises in the bright centers of 'cells,' cools off and then sinks below the surface in dark lanes in a process known as convection. In these dark lanes we can also see the tiny, bright markers of magnetic fields. Never before seen to this clarity, these bright specks are thought to channel energy up into the outer layers of the solar atmosphere called the corona. These bright spots may be at the core of why the solar corona is more than a million degrees.

Just released first images from the National Science Foundation's Daniel K. Inouye Solar Telescope reveal unprecedented detail of the sun's surface and preview the world-class products to come from this preeminent 4-meter solar telescope. NSF's Inouye Solar Telescope, on the summit of Haleakala, Maui, in Hawai'i, will enable a new era of solar science and a leap forward in understanding the sun and its impacts on our planet.

Activity on the sun, known as space weather, can affect systems on Earth. Magnetic eruptions on the sun can impact air travel, disrupt satellite communications and bring down power grids, causing long-lasting blackouts and disabling technologies such as GPS.

The first images from NSF's Inouye Solar Telescope show a close-up view of the sun's surface, which can provide important detail for scientists. The images show a pattern of turbulent "boiling" plasma that covers the entire sun. The cell-like structures -- each about the size of Texas -- are the signature of violent motions that transport heat from the inside of the sun to its surface. That hot solar plasma rises in the bright centers of "cells," cools, then sinks below the surface in dark lanes in a process known as convection.

"Since NSF began work on this ground-based telescope, we have eagerly awaited the first images," said France Córdova, NSF director. "We can now share these images and videos, which are the most detailed of our sun to date. NSF's Inouye Solar Telescope will be able to map the magnetic fields within the sun's corona, where solar eruptions occur that can impact life on Earth. This telescope will improve our understanding of what drives space weather and ultimately help forecasters better predict solar storms."

Expanding knowledge

The sun is our nearest star -- a gigantic nuclear reactor that burns about 5 million tons of hydrogen fuel every second. It has been doing so for about 5 billion years and will continue for the other 4.5 billion years of its lifetime. All that energy radiates into space in every direction, and the tiny fraction that hits Earth makes life possible. In the 1950s, scientists figured out that a solar wind blows from the sun to the edges of the solar system. They also concluded for the first time that we live inside the atmosphere of this star. But many of the sun's most vital processes continue to confound scientists.

"On Earth, we can predict if it is going to rain pretty much anywhere in the world very accurately, and space weather just isn't there yet," said Matt Mountain, president of the Association of Universities for Research in Astronomy, which manages the Inouye Solar Telescope. "Our predictions lag behind terrestrial weather by 50 years, if not more. What we need is to grasp the underlying physics behind space weather, and this starts at the sun, which is what the Inouye Solar Telescope will study over the next decades."

The motions of the sun's plasma constantly twist and tangle solar magnetic fields . Twisted magnetic fields can lead to solar storms that can negatively affect our technology-dependent modern lifestyles. During 2017's Hurricane Irma, the National Oceanic and Atmospheric Administration reported that a simultaneous space weather event brought down radio communications used by first responders, aviation and maritime channels for eight hours on the day the hurricane made landfall.

Finally resolving these tiny magnetic features is central to what makes the Inouye Solar Telescope unique. It can measure and characterize the sun's magnetic field in more detail than ever seen before and determine the causes of potentially harmful solar activity.

"It's all about the magnetic field," said Thomas Rimmele, director of the Inouye Solar Telescope. "To unravel the sun's biggest mysteries, we have to not only be able to clearly see these tiny structures from 93 million miles away but very precisely measure their magnetic field strength and direction near the surface and trace the field as it extends out into the million-degree corona, the outer atmosphere of the sun."

Better understanding the origins of potential disasters will enable governments and utilities to better prepare for inevitable future space weather events. It is expected that notification of potential impacts could occur earlier -- as much as 48 hours ahead of time instead of the current standard, which is about 48 minutes. This would allow more time to secure power grids and critical infrastructure and to put satellites into safe mode.

The engineering

To achieve the proposed science, this telescope required important new approaches to its construction and engineering. Built by NSF's National Solar Observatory and managed by AURA, the Inouye Solar Telescope combines a 13-foot (4-meter) mirror -- the world's largest for a solar telescope -- with unparalleled viewing conditions at the 10,000-foot Haleakala summit.

Focusing 13 kilowatts of solar power generates enormous amounts of heat -- heat that must be contained or removed. A specialized cooling system provides crucial heat protection for the telescope and its optics. More than seven miles of piping distribute coolant throughout the observatory, partially chilled by ice created on site during the night.

The dome enclosing the telescope is covered by thin cooling plates that stabilize the temperature around the telescope, helped by shutters within the dome that provide shade and air circulation. The "heat-stop" (a high-tech, liquid-cooled, doughnut-shaped metal) blocks most of the sunlight's energy from the main mirror, allowing scientists to study specific regions of the sun with unparalleled clarity.

The telescope also uses state-of-the-art adaptive optics to compensate for blurring created by Earth's atmosphere. The design of the optics ("off-axis" mirror placement) reduces bright, scattered light for better viewing and is complemented by a cutting-edge system to precisely focus the telescope and eliminate distortions created by the Earth's atmosphere. This system is the most advanced solar application to date.

"With the largest aperture of any solar telescope, its unique design, and state-of-the-art instrumentation, the Inouye Solar Telescope -- for the first time -- will be able to perform the most challenging measurements of the sun," Rimmele said. "After more than 20 years of work by a large team devoted to designing and building a premier solar research observatory, we are close to the finish line. I'm extremely excited to be positioned to observe the first sunspots of the new solar cycle just now ramping up with this incredible telescope."

New era of solar astronomy

NSF's new ground-based Inouye Solar Telescope will work with space-based solar observation tools such as NASA's Parker Solar Probe (currently in orbit around the sun) and the European Space Agency/NASA Solar Orbiter (soon to be launched). The three solar observation initiatives will expand the frontiers of solar research and improve scientists' ability to predict space weather.

"It's an exciting time to be a solar physicist," said Valentin Pillet, director of NSF's National Solar Observatory. "The Inouye Solar Telescope will provide remote sensing of the outer layers of the sun and the magnetic processes that occur in them. These processes propagate into the solar system where the Parker Solar Probe and Solar Orbiter missions will measure their consequences. Altogether, they constitute a genuinely multi-messenger undertaking to understand how stars and their planets are magnetically connected."

"These first images are just the beginning," said David Boboltz, a program director in NSF's Division of Astronomical Sciences who oversees the facility's construction and operations. "Over the next six months, the Inouye telescope's team of scientists, engineers and technicians will continue testing and commissioning the telescope to make it ready for use by the international solar scientific community. The Inouye Solar Telescope will collect more information about our sun during the first 5 years of its lifetime than all the solar data gathered since Galileo first pointed a telescope at the sun in 1612."

---

Story Source:

Materials provided by National Science Foundation. Note: Content may be edited for style and length.

Low-energy solar particles from beyond Earth found near the Sun

Sun (stock image; elements furnished by NASA).

Using data from NASA's Parker Solar Probe (PSP), a team led by Southwest Research Institute identified low-energy particles lurking near the Sun that likely originated from solar wind interactions well beyond Earth orbit. PSP is venturing closer to the Sun than any previous probe, carrying hardware SwRI helped develop. Scientists are probing the enigmatic features of the Sun to answer many questions, including how to protect space travelers and technology from the radiation associated with solar events.

"Our main goal is to determine the acceleration mechanisms that create and transport dangerous high-energy particles from the solar atmosphere into the solar system, including the near-Earth environment," said Dr. Mihir Desai, a mission co-investigator on the Integrated Science Investigation of the Sun (IS?IS) instrument suite, a multi-institutional project led by Principal Investigator Prof. Dave McComas of Princeton University.. IS?IS consists of two instruments, Energetic Particle Instrument-High (EPI-Hi) and Energetic Particle Instrument-Low (EPI-Lo). "With EPI-Lo, we were able to measure extremely low-energy particles unexpectedly close to the solar environment. We considered many explanations for their presence, but ultimately determined they are the smoking gun pointing to interactions between slow- and fast-moving regions of the solar wind that accelerate high-energy particles from beyond the orbit of Earth. Some of those travel back toward the Sun, slowing against the tide of the outpouring solar wind but still retaining surprisingly high energies."

PSP, which will travel within 4 million miles of the Sun's surface, is collecting new solar data to help scientists understand how solar events, such as coronal mass ejections, impact life on Earth. During the rising portion of the Sun's activity cycle, our star releases huge quantities of energized matter, magnetic fields and electromagnetic radiation in the form of coronal mass ejections (CMEs). This material is integrated into the solar wind, the steady stream of charged particles released from the Sun's upper atmosphere. The high-energy solar energetic particles (SEPs) present a serious radiation threat to human explorers living and working outside low-Earth orbit and to technological assets such as communications and scientific satellites in space. The mission is making the first-ever direct measurements of both the low-energy source populations as well as the more hazardous, higher-energy particles in the near-Sun environment, where the acceleration takes place.

When the Sun's activity reaches a lull, roughly about every 11 years, solar equatorial regions emit slower solar wind streams, traveling around 1 million miles per hour, while the poles spew faster streams, traveling twice as fast at 2 million miles per hour. Stream Interaction Regions (SIRs) are created by interactions at boundaries between the fast and slow solar wind. Fast-moving streams tend to overtake slower streams that originate westward of them on the Sun, forming turbulent corotating interaction regions (CIRs) that produce shock waves and accelerated particles, not unlike those produced by CMEs.

"For the first time, we observed low-energy particles from these CIRs near the orbit of Mercury," Desai said. "We also compared the PSP data with data from STEREO, another solar energy probe. By measuring the full range of energetic populations and correlating the data with other measurements, we hope to get a clear picture of the origin and the processes that accelerate these particles. Our next step is to integrate the data into models to better understand the origin of SEPs and other materials. Parker Solar Probe will solve many puzzling scientific questions -- and is guaranteed to generate new ones as well."

---

Story Source:

Materials provided by Southwest Research Institute. Note: Content may be edited for style and length.

'Parentese' helps parents, babies make 'conversation' and boosts language development

Mother talking to baby (stock image).

Used in virtually all of the world's languages, parentese is a speaking style that draws baby's attention. Parents adopt its simple grammar and words, plus its exaggerated sounds, almost without thinking about it.

But if parents knew the way they speak could help baby learn, would they alter their speech?

A new study from the Institute for Learning & Brain Sciences, or I-LABS, at the University of Washington suggests they would, to baby's benefit. Researchers examined how parent coaching about the value of parentese affected adults' use of it with their own infants, and demonstrated that increases in the use of parentese enhanced children's later language skills.

The study, published online Feb. 3 in the Proceedings of the National Academy of Sciences, finds that parents who participated in individual coaching sessions used parentese more often than control-group parents who were not coached, and that coaching produced more parent-child "conversational turns" and increased the child's language skills months later.

"We've known for some time that the use of parentese is associated with improved language outcomes," said Patricia Kuhl, I-LABS co-director and professor of speech and hearing sciences at the UW. "But we didn't know why. We believe parentese makes language learning easier because of its simpler linguistic structure and exaggerated sounds. But this new work suggests a more fundamental reason.

"We now think parentese works because it's a social hook for the baby brain -- its high pitch and slower tempo are socially engaging and invite the baby to respond."

Parentese is not what is often called "baby talk," which is generally a mash-up of silly sounds and nonsense words. Instead, it is fully grammatical speech that involves real words, elongated vowels and exaggerated tones of voice. Spoken directly to the child, it sounds happy and engaged, and helps infants tune in socially to their parents and respond, even if only through babbling.

In a 2018 study, I-LABS researchers tracked use of parentese among adults and their 6-month-old infants, and found that babies whose parents participated in parentese coaching sessions babbled more and produced more words by age 14 months than infants whose parents were not directed in the technique.

The new study focuses on the long-term outcomes of parent coaching and how it led to changes in the parents' language, in parent-child conversation, and eventually, in the child's speech at 18 months.

"We had no idea that parents would respond so positively to information about how their own speech to the child affects the child's language development. Parent coaching gave parents a measurement tool, almost like a Fitbit for parentese, and it worked," said lead author Naja Ferjan Ramírez, a UW assistant professor of linguistics.

To assess child language output, all families in the study were given a lightweight recorder, which the child wore in a specially designed vest during four separate weekends at ages 6, 10, 14 and 18 months. The device recorded both parent and infant speech over the entirety of two consecutive days, so that researchers could measure parents' use of parentese, parent-child conversational turns, as well as infant language production -- either babbling or actual words. Parent coaching sessions occurred at 6, 10 and 14 months.

For the 48 families randomly assigned to receive coaching, the sessions provided guidance and feedback on specific communication strategies, such as using parentese, speaking directly to the child and engaging the child in back-and-forth exchanges known as conversational turns. In reviewing recordings with parents, researchers played back recordings of parents' language behaviors and measured them against research-based targets for child language development. Parents were encouraged to include language as part of daily routines and were given language-interaction tips in the form of cards with "brain building" tips from Vroom, a program of the Bezos Family Foundation.

All parents in the study already used parentese at the beginning of the project, but their use varied greatly, the researchers said. Those in the coaching group learned more about the cognitive and social benefits of parentese, when and how to use it to promote interaction with their child, and the positive effects that parentese could have on their child's language development.

The results show that parent coaching resulted in an increased use of parentese and infant vocalizations that continued to grow after the end of the parent coaching sessions. Between 14- and 18-months, coached families showed a drastic jump in conversational turn-taking and child vocalizations. Children of coached parents produced real words -- such as "banana" or "milk" -- at almost twice the frequency of children whose parents were in the control group. Parent surveys estimated that the children's 18-month vocabulary averaged around 100 words among children of coached families, compared to 60 words among children in the control group.

"We know that language skills in infancy predict subsequent stages in language development, so enhancements in language behaviors in infancy could therefore have cascading effects on speech development over time," said Ferjan Ramírez.

Kuhl added, "Language evolved to facilitate the social communication skills that are essential for survival of the species. In this study, we observe firsthand how parents' language and social engagement can promote baby's initial responsive coos, which become words, and then sentences -- educating infants in the art of human communication."

The study was funded by the Overdeck Family Foundation and UW I-LABS Ready Mind Project. Sarah Roseberry Lytle, outreach and education director at I-LABS, was a co-author.

---

Story Source:

Materials provided by University of Washington. Original written by Kim Eckart. Note: Content may be edited for style and length.