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An image of dust over the Sahara Desert.

Earth’s atmosphere far dustier than previously believed

An image of dust over the Sahara Desert.

Dust over the Sahara Desert (Photo Credit: NASA GSFC)

Dust is a key component of Earth’s climate system. When it interacts with clouds, oceans and the sun’s radiation, it has an overall impact on our planet’s living systems, affecting everything from weather and rainfall to global warming.

There are two types of dust in the atmosphere, both kicked up by high-velocity winds in dry areas. Fine dust tends to cool because it scatters sunlight, much like clouds do. Coarse dust, which is larger in size and originates in places like the Sahara Desert, tends to warm the atmosphere, much like greenhouse gases.

Knowing precisely how much coarse dust is in the atmosphere is essential for understanding not only the atmospheric phenomena that dust influences but also the degree to which dust may be warming the planet.

Now, UCLA scientists report that there is four times the amount of coarse dust in Earth’s atmosphere than is currently simulated by climate models. Their findings appear in the journal Science Advances.

The researchers found that Earth’s atmosphere contains 17 million metric tons of coarse dust — equivalent to 17 million elephants or the mass of every person in America put together.

“To properly represent the impact of dust as a whole on the Earth system, climate models must include an accurate treatment of coarse dust in the atmosphere,” said the study’s first author, Adeyemi Adebiyi, a postdoctoral researcher in UCLA’s Department of Atmospheric and Oceanic Sciences and a recipient of the University of California President’s Postdoctoral Fellowship.

By plugging this amount of missing coarse dust into models, Adebiyi said, it increases the likelihood that the net amount of dust overall — both fine and coarse — is warming rather than cooling the Earth’s climate system, from air to oceans.

Coarse dust particles warm the Earth’s entire climate system by absorbing both incoming radiation from the sun and outgoing radiation from the Earth’s surface. These particles can impact stability and circulation within our atmosphere, which may affect atmospheric phenomena like hurricanes.

Adebiyi worked with Jasper Kok, a UCLA associate professor of atmospheric and oceanic sciences, to determine the actual amount of coarse dust in the atmosphere by analyzing dozens of published aircraft-based observations, including recent measurements taken over the Sahara Desert, and comparing those with half a dozen widely used global atmospheric model simulations.

“When we compared our results with what is predicted by current climate models, we found a drastic difference,” Kok said. “State-of-the-art climate models account for only 4 million metric tons, but our results showed more than four times that amount.”

In addition, Adebiyi and Kok found that coarse dust leaves the atmosphere less quickly than current climate models predict. Air has a tendency to mix more turbulently when dust is present. In the case of the Sahara, air and dust mix in ways that push the dust upward, which can work against gravity and keep the dust in the air much longer, they said.

The scientists’ findings also show that because dust particles stay in the atmosphere longer, they are ultimately deposited further from their source than has been predicted by these models or explained by current theory. Dust particles blown from the Sahara, for example, can travel thousands of miles in the atmosphere, reaching as far as the Caribbean and the United States.

When desert dust ends up in oceans, it may stimulate the productivity of ocean ecosystems and increase the amount of carbon dioxide absorbed by the oceans.

Due to the way coarse dust interacts with the sun’s energy and clouds, it can also have a major impact on the timing of precipitation, as well as how much, or how little, rain falls.

“Models have been an invaluable tool for scientists,” said Adebiyi, “but when they miss most of the coarse dust in the atmosphere, it underestimates the impact that this type of dust has on critical aspects of life on Earth, from precipitation to cloud cover to ocean ecosystems to global temperature.”

This article originally appeared in the UCLA Newsroom.

A photo of a valley oak tree.

UCLA College Celebrates Earth Day

A photo of a Griffith Park vista; the view of the Los Angeles skyline from Griffith Park.

Los Angeles County is home to more than 4,000 distinct species of plants and animals, and the sustainability plan aims for “no loss of native biodiversity.” (Photo Credit: Jake Dobkin)

Not only does this mark its 50th anniversary, this Earth Day is unlike any other we have seen as the global pandemic continues to impact the way we live our lives. Yes, it has disrupted our daily routines but it has also benefited the environment in myriad ways. For example, freeways once clogged with traffic have opened up, clearing the air and making way for bright blue skies and views for miles. Even before COVID-19, UCLA College faculty members and teams were out in the field and in their labs, working on groundbreaking research and advising on county and statewide plans. In honor of Earth Day, we are highlighting stories about conservation, sustainability, global warming, solar geoengineering and protecting our precious ecosystems.

 

A photo of vegetation and mountains in California's Anza-Borrego State Park.

Vegetation and mountains in California’s Anza-Borrego State Park. (Photo Credit: Sean Brenner/UCLA)

UCLA to lead $10 million California conservation project

UCLA scientists are leading a $10 million project to help California officials make ecologically wise decisions as the state continues to confront the effects of climate change. The initiative will give California officials scientific data they can use to make decisions about conserving the state’s ecosystems.

A photo of a valley oak tree.

The valley oak, the largest oak in California, grows to over 100 feet tall and provides habitat and food for a variety of animals. (Photo Credit: Victoria Sork/UCLA)

One of California’s iconic tree species offers lessons for conservation

New research led by UCLA evolutionary biologist Victoria Sork examines whether the trees being replanted in the wake of California’s fires will be able to survive a climate that is continuing to warm. The study, which is published in the Proceedings of the Natural Academy of Sciences, focuses on California’s iconic valley oak.

A photo of a Griffith Park vista; the view of the Los Angeles skyline from Griffith Park.

Los Angeles County is home to more than 4,000 distinct species of plants and animals, and the sustainability plan aims for “no loss of native biodiversity.” (Photo Credit: Jake Dobkin)

L.A. County taps UCLA to help create first-ever sustainability plan

The Los Angeles County Board of Supervisors unanimously approved an ambitious sustainability plan that calls for phasing out fossil fuels to address climate change and improve quality of life in the region. Sixteen UCLA researchers contributed to the OurCounty plan, which was created by the county’s Chief Sustainability Office.

A photo of the Santa Monica Pier at night.

The Santa Monica Pier at night. Artificial light can cause problems for a range of species that live and breed in coastal environments. (Photo Credit: William Chen/Pexels)

Study draws Southern California coastal light pollution into focus

Artificial light is known to disrupt mating cycles in species along the Southern California coast. A team of UCLA and University of Southern California researchers led by Travis Longcore, UCLA adjunct professor of urban conservation biology, has mapped light pollution conditions that will be used to inform decisions about future infrastructure and construction plans.

A photo of members of the UCLA Center for Diverse Leadership in Science, which was founded by Aradhna Tripati, associate professor in the UCLA Institute of the Environment and Sustainability.

Members of the Center for Diverse Leadership in Science, which was founded by Professor Aradhna Tripati, third row, far right, and their colleagues. (Photo: Courtesy of Aradhna Tripati)

Professor pays it forward by promoting diversity and environmental justice

When she was appointed in 2009, Aradhna Tripati was the first woman of color out of 50 faculty in UCLA’s Institute of the Environment and Sustainability. Along with colleagues in UCLA’s Anthropology department and American Indian Studies Center, she conducts community engaged research on water in the context of global warming in the southwestern United States. She also formed the first university-based center for diversity in environmental science, with the goal of inspiring a generation of leaders that matches the demographics of the U.S. population.

Andrea Bertozzi (Photo Credit: Courtesy of Andrea Bertozzi)

Mathematics professors earn NSF grant to calculate COVID-19 transmission rates

A photo of Andrea Bertozzi

Andrea Bertozzi (Photo Credit: Courtesy of Andrea Bertozzi)

Uncertainty about COVID-19 transmission rates has been one of the major challenges for health care systems in the United States and around the world.

UCLA mathematics professors Andrea Bertozzi and Mason Porter will use mathematical modeling, incorporating the specific features of COVID-19, to provide insights to those who are developing strategies to mitigate the spread of the disease.

Bertozzi and Porter have been awarded a $200,000 rapid-response research grant from the National Science Foundation, which has called for proposals with the potential to address the spread of COVID-19.

Many public health and infectious disease experts believe the actual transmission of COVID-19 is likely much higher than what has been publicly reported. The UCLA project will extend prior research on contagions, factoring in multiple transmission methods, human behavior patterns, current data and more. It also will provide training for a postdoctoral scholar, a doctoral student and two undergraduates.

Bertozzi and her research team have already published a preprint of a research paper on the challenges of modeling and forecasting the spread of COVID-19, and she and Porter are conducting research on another related paper as part of the project.

Bertozzi holds UCLA’s Betsy Wood Knapp Chair for Innovation and Creativity.

The award is co-funded by NSF programs in applied mathematics and computational mathematics and its office of multidisciplinary activities.

This article originally appeared in the UCLA Newsroom.

 

A photo of Professor Neil Garg

How did organic chemistry become so beloved at UCLA? Professor Neil Garg is glad you asked

People who don’t know Neil Garg may be shocked to learn he has made organic chemistry — the chemistry of molecules made of carbon — one of UCLA’s most beloved and popular undergraduate courses. Students wait for years to get into his class and do celebratory dances when they learn they’re enrolled.

Garg, the Kenneth N. Trueblood Professor of Chemistry and Biochemistry, recently explained how he made the subject so popular and shared some of his teaching techniques in an article published in the Journal of Biological Chemistry. In 2018, Garg became the recipient of the country’s premier university teaching award, the Robert Foster Cherry Award for Great Teaching, given once every two years by Baylor University.

His undergraduate course Chemistry 14D, “Organic Reactions and Pharmaceuticals,” is very demanding. On exams, he asks students — mostly second-year, non-chemistry majors — to solve difficult problems he did not learn to solve until his first year of graduate school at Caltech. Students, for example, are asked to create a reasonable chemical synthesis of molecules they have never seen before. By the end of his course, more than two-thirds of the class can solve these problems.

A photo of Professor Neil Garg

Neil Garg reveals the teaching techniques that helped him to win the country’s premier university teaching award. (Photo Credit: Coral von Zumwalt)

“What is also striking,” Garg writes, “is that the students show impeccable creativity in their solutions, often providing reasonable responses that bear no resemblance to what is shown on the answer key, earning full credit. … My goal is always for students to do extraordinary things and learn to solve the hardest problems I can offer.”

In student surveys about Chemistry 14D more than two-thirds of the students rate their interest in organic chemistry as high, and fewer than 4% rate their interest in the subject as low. This is a dramatic shift from the start of the course when fewer than 10% reported a high rating, and more than 60% reported their interest as low.

In the article, Garg, who is also chair of UCLA’s department of chemistry and biochemistry, but not currently teaching organic chemistry, offers more than a dozen tips for teaching complex science. Among his practices:

-It’s essential to explain the relevance of organic chemistry to students and focus the class on problem-solving, critical thinking and creativity, rather than memorization. He teaches students that for each chemical reaction, there is a logic associated with how and why the reaction takes place. One of his students said she feels “like Sherlock Holmes when solving retrosynthesis problems.”

-He and his teaching assistants continually show students how much they care. Former student Elizabeth Matusov said, “He feels like a friend who happens to be teaching a really difficult class. He’s easily the best professor I’ve ever had. I would take any class with him. We all would.”

-He learns students’ names and calls on them by name, even in a class with 400 students. He stays in touch with hundreds of his former students, including some from 20 years ago.

-He teaches the fundamental vocabulary of organic chemistry and the rules of chemical reactivity, and performs in-class demonstrations with students.

-He poses questions that students answer with clickers, so he can immediately learn what they understand and what concepts require further explanation.

-More than 1,300 of his students have teamed up to make hundreds of music videos that have been viewed around the world hundreds of thousands of times. Many of the best are in Garg’s Chemistry 14D Music Video Hall of Fame, which features such student classics as “I Will Survive,” “Alkenes Are Used for These,” “Chem 14 Dreams Mashup” and “Say Alkane.” While teaching a semester at Baylor University last year, his undergraduate students teamed up to create 37 videos, including a chemistry adaptation of ABBA’s “Dancing Queen.”

-He has created educational resources for students, including BACON (Biology And Chemistry Online Notes), a set of fun and engaging online tutorials that make connections between organic chemistry and sports, health, genetics and popular television shows, among other topics. Other chemistry resources that are free and being used worldwide are a smartphone app called “Backside Attack” that teaches organic chemistry concepts; qrchem.net; and rschemistry.com. QR Chem, a molecule visualization app created by Garg and some of his UCLA students, is being used in more than 160 countries.

Summing up his teaching philosophy, Garg asks, “How did organic chemistry become one of UCLA’s most popular classes? Teaching is all about the students. We must challenge them, support them, make them feel connected to the class and give them opportunities to do amazing things.”

In an acknowledgment at the end of the article, Garg thanks, among others, his “thousands of inspiring students.”

Garg and his family live in a campus residence hall as part of UCLA’s faculty-in-residence program, which allows him to dine with students, advise them, go on trips with them and inspire them daily with his passion for chemistry.

This article originally appeared in the UCLA Newsroom.

A photo of a 3D atomic structure information of a 2D material that was previously inaccessible due to the limitations of 2D images. A 2D image is shown beneath the 3D atomic coordinates of molybdenum in blue, sulfur in yellow and rhenium dopants in orange.

UCLA-led research team produces most accurate 3D images of ‘2D materials’

A photo of a 3D atomic structure information of a 2D material that was previously inaccessible due to the limitations of 2D images. A 2D image is shown beneath the 3D atomic coordinates of molybdenum in blue, sulfur in yellow and rhenium dopants in orange.

Image showing the 3D atomic coordinates of molybdenum (blue), sulfur (yellow) and added rhenium (orange). A 2D image is shown beneath the 3D model. (Photo Credit: Dennis Kim/UCLA)

A UCLA-led research team has produced in unprecedented detail experimental three-dimensional maps of the atoms in a so-called 2D material — matter that isn’t truly two-dimensional but is nearly flat because it’s arranged in extremely thin layers, no more than a few atoms thick.

Although 2D-materials–based technologies have not yet been widely used in commercial applications, the materials have been the subject of considerable research interest. In the future, they could be the basis for semiconductors in ever smaller electronics, quantum computer components, more-efficient batteries, or filters capable of extracting freshwater from saltwater.

The promise of 2D materials comes from certain properties that differ from how the same elements or compounds behave when they appear in greater quantities. Those unique characteristics are influenced by quantum effects — phenomena occurring at extremely small scales that are fundamentally different from the classical physics seen at larger scales. For instance, when carbon is arranged in an atomically thin layer to form 2D graphene, it is stronger than steel, conducts heat better than any other known material, and has almost zero electrical resistance.

But using 2D materials in real-world applications would require a greater understanding of their properties, and the ability to control those properties. The new study, which was published in Nature Materials, could be a step forward in that effort.

The researchers showed that their 3D maps of the material’s atomic structure are precise to the picometer scale — measured in one-trillionths of a meter. They used their measurements to quantify defects in the 2D material, which can affect their electronic properties, as well as to accurately assess those electronic properties.

“What’s unique about this research is that we determine the coordinates of individual atoms in three dimensions without using any pre-existing models,” said corresponding author Jianwei “John” Miao, a UCLA professor of physics and astronomy. “And our method can be used for all kinds of 2D materials.”

Miao is the deputy director of the STROBE National Science Foundation Science and Technology Center and a member of the California NanoSystems Institute at UCLA. His UCLA lab collaborated on the study with researchers from Harvard University, Oak Ridge National Laboratory and Rice University.

The researchers examined a single layer of molybdenum disulfide, a frequently studied 2D material. In bulk, this compound is used as a lubricant. As a 2D material, it has electronic properties that suggest it could be employed in next-generation semiconductor electronics. The samples being studied were “doped” with traces of rhenium, a metal that adds spare electrons when replacing molybdenum. That kind of doping is often used to produce components for computers and electronics because it helps facilitate the flow of electrons in semiconductor devices.

To analyze the 2D material, the researchers used a new technology they developed based on scanning transmission electron microscopy, which produces images by measuring scattered electrons beamed through thin samples. Miao’s team devised a technique called scanning atomic electron tomography, which produces 3D images by capturing a sample at multiple angles as it rotates.

The scientists had to avoid one major challenge to produce the images: 2D materials can be damaged by too much exposure to electrons. So for each sample, the researchers reconstructed images section by section and then stitched them together to form a single 3D image — allowing them to use fewer scans and thus a lower dose of electrons than if they had imaged the entire sample at once.

The two samples each measured 6 nanometers by 6 nanometers, and each of the smaller sections measured about 1 nanometer by 1 nanometer. (A nanometer is one-billionth of a meter.)

The resulting images enabled the researchers to inspect the samples’ 3D structure to a precision of 4 picometers in the case of molybdenum atoms — 26 times smaller than the diameter of a hydrogen atom. That level of precision enabled them to measure ripples, strain distorting the shape of the material, and variations in the size of chemical bonds, all changes caused by the added rhenium — marking the most accurate measurement ever of those characteristics in a 2D material.

“If we just assume that introducing the dopant is a simple substitution, we wouldn’t expect large strains,” said Xuezeng Tian, the paper’s co-first author and a UCLA postdoctoral scholar. “But what we have observed is more complicated than previous experiments have shown.”

The scientists found that the largest changes occurred in the smallest dimension of the 2D material, its three-atom-tall height. It took as little as a single rhenium atom to introduce such local distortion.

► Read a Nature analysis of the UCLA-led study

Armed with information about the material’s 3D coordinates, scientists at Harvard led by Professor Prineha Narang performed quantum mechanical calculations of the material’s electronic properties.

“These atomic-scale experiments have given us a new lens into how 2D materials behave and how they should be treated in calculations, and they could be a game changer for new quantum technologies,” Narang said.

Without access to the sort of measurements generated in the study, such quantum mechanical calculations conventionally have been based on a theoretical model system that is expected at a temperature of absolute zero.

The study indicated that the measured 3D coordinates led to more accurate calculations of the 2D material’s electronic properties.

“Our work could transform quantum mechanical calculations by using experimental 3D atomic coordinates as direct input,” said UCLA postdoctoral scholar Dennis Kim, a co-first author of the study. “This approach should enable material engineers to better predict and discover new physical, chemical and electronic properties of 2D materials at the single-atom level.”

Other authors were Yongsoo Yang, Yao Yang and Yakun Yuan of UCLA; Shize Yang and Juan-Carlos Idrobo of Oak Ridge National Laboratory; Christopher Ciccarino and Blake Duschatko of Harvard; and Yongji Gong and Pulickel Ajayan of Rice.

The research was supported by the U.S. Department of Energy, the U.S. Army Research Office, and STROBE National Science Foundation Science and Technology Center. The scanning transmission electron microscopy experiments were conducted at the Center for Nanophase Materials Sciences, a DOE user facility at Oak Ridge National Laboratory.

This article originally appeared in the UCLA Newsroom.

A photo of the Owens Valley lakebed.

Effort to limit dust pollution in Owens Valley is advancing, but still room to improve

A photo of the Owens Valley lakebed.

The Owens Valley lakebed with currently approved dust mitigation measures. (Photo Credit: David Colgan/UCLA)

The century-long battle over water between California’s Owens Valley and Los Angeles is nothing short of epic.

In 1974, the conflict was immortalized in the film “Chinatown.” The latest chapter comes in a more stoic but important form: a 157-page report from the National Academies of Sciences, Engineering and Medicine. The publication was created by a panel of experts that includes UCLA atmospheric dust specialist Gregory Okin.

Beginning in the late 1800s, William Mulholland quietly bought up land and water rights in Owens Valley, and in 1913, he started delivering the water from Owens Lake 233 miles south via aqueduct to a fast-growing Los Angeles.

The population of Los Angeles was 102,000 in 1910, but it had reached 319,000 in 1920 and then soared to 2 million by the middle of the century. Owens Valley, its lake drained of water, had become the largest source of dust in North America.

That dust included particulate matter measuring 10 micrometers or less in diameter, pollution that gets deep into people’s lungs and causes respiratory problems, particularly for sensitive groups. Ranchers, indigenous people and other residents of the valley were incensed, having lost their water and gained unhealthy air in its place.

The National Academies’ peer-reviewed report comes following decades of litigation that required the Los Angeles Department of Water and Power to take actions to mitigate the dust problem. Over the past two decades, the department has spent $2 billion on the effort.

And researchers found good news: Efforts between the department and Great Basin Unified Air Pollution Control District to control the issue have gone well. The work includes using gravel, managed vegetation and shallow flooding to mitigate dust. The air pollution district is a government agency responsible for protecting air quality in the east-central part of the state, near the Nevada border. It battled the Department of Water and Power in court for decades, but outside the courtroom the relationship is less contentious.

“The teams of people working on the ground together have been very successful,” said Okin, who is also a member of the UCLA Institute of the Environment and Sustainability. “There are still air quality exceedances that occur, but they are drastically smaller in magnitude and frequency than they were prior to 2000.”

That doesn’t mean there isn’t room for improvement. The report also recommended that processes for minimizing dust established 20 years ago should be updated with new technology and processes that would also help save water and power and preserve cultural and aesthetic values.

“Despite the fact that they’ve done a great job, they’ve done it in an ad hoc manner,” Okin said, referring to the two agencies. “There’s not a lot of logic as to what is being done and where.”

A photo of a crowd of 30,000 people who watched the first water cascade through the aqueduct in the San Fernando Valley.

A crowd of 30,000 watched the first water cascade through the aqueduct in the San Fernando Valley. (Photo Credit: Courtesy of waterandpower.org)

The methods workers can use to mitigate dust are strictly controlled by a series of legal agreements. And testing new methods poses a challenge, because testing is prohibited in the areas of the valley in which dust pollution has been substantially controlled.

“The only place you can test new measures is in areas that don’t need to be controlled, which is crazy,” Okin said.

The report suggests that the air pollution control district and the Department of Water and Power work together to redesign the entire system of dust control in the lakebed.

“The current work is probably using more water, power and heavy machinery than it needs to,” Okin said.

Better managing the area could also be a boon for wildlife. Currently, one of the main approaches to mitigating dust in the area is to plant grass, which requires a lot of irrigation. Okin suggested other native species could replace grass in some areas, which would save water and create new living spaces for birds, rare aquatic life and other species wildlife.

The report also notes that planning for future efforts must account for also climate change, which is projected to increase temperatures and make precipitation patterns and dry spells more extreme. The 2017 rainy season, for example, flooded the valley with more water than the Los Angeles Aqueduct could take, causing water levels in the mostly-dry lake to rise substantially.

The competing interests of the two main players could make it difficult to improve the situation further, Okin said. While the air pollution control district is primarily interested in dust mitigation, the Department of Water and Power cares mostly about conserving water as a resource. Bringing new efficiency and sustainability to the process would likely require further involvement of third parties such as the academies that created the report.

It’s been more than a century since Mulholland said, “There it is, take it,” as the first Owens Valley water flowed through the aqueduct into Los Angeles. Now, the question is how the next century of this drama, which affects the lives of millions, will unfold.

This article originally appeared in the UCLA Newsroom.

A photo collage: from left, top row: Elaine Hsiao, Andrea Ghez, Sarah Stein. From left, bottom row: Heather Adams and Lynn Vavreck.

UCLA College Celebrates International Women’s Day

A photo collage: from left, top row: Elaine Hsiao, Andrea Ghez, Sarah Stein. From left, bottom row: Heather Adams and Lynn Vavreck.

From left, top row: Elaine Hsiao, Andrea Ghez, Sarah Stein. From left, bottom row: Heather Adams and Lynn Vavreck.

On International Women’s Day we give a shout-out to five incredible UCLA College faculty whose research and accomplishments are truly awe-inspiring—including discoveries about our galaxy’s black hole, landing on The Economist’s “Best of 2019” book list, spearheading one of the largest public opinion surveys for the 2020 election, revealing how anti-depressants affect our gut microbiome, and advocating for transfer students. See our highlights below.

Physical Sciences

A photo of Andrea Ghez.

Andrea Ghez (Photo Credit: Christopher Dibble)

Astronomers discover class of strange objects near our galaxy’s enormous black hole

Astronomers from UCLA’s Galactic Center Orbits Initiative have discovered new objects that “look like gas and behave like stars,” said co-author Andrea Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics and director of the UCLA Galactic Center Group.

 

Social Sciences

A photo of Lynn Vavreck.

Lynn Vavreck (Photo Credit: UCLA)

UCLA political scientists launch one of largest-ever public opinion surveys for run-up to 2020

UCLA political scientists Lynn Vavreck and Chris Tausanovitch launch one of largest-ever public opinion surveys for the run-up to 2020 elections.

 

Life Sciences

A photo of Elaine Hsiao.

Elaine Hsiao (Photo Credit: Reed Hutchinson/UCLA)

Study shows how serotonin and a popular anti-depressant affect the gut’s microbiota

Senior author Elaine Hsiao, along with a team of researchers, hopes to build on their current study to learn whether microbial interactions with antidepressants have consequences for health and disease.

 

Humanities

A photo of Sarah Abrevaya Stein.

Sarah Abrevaya Stein (Photo Credit: Caroline Libresco)

Professor’s book about Sephardic Jews chosen as a Best of 2019

The Economist has named to its Best of 2019 list, “Family Papers: A Sephardic Journey Through the Twentieth Century,” by Sarah Abrevaya Stein, Sady and Ludwig Kahn Director, Alan D. Leve Center for Jewish Studies.

 

Undergraduate Education

A photo of Heather Adams, first row center, former director of the UCLA Transfer Student Center.

Heather Adams, first row center. (Photo Credit: Ivan Mendez/UCLA)

UCLA’s Heather Adams wins national award for work helping transfer students

Adams was honored by the National Institute for the Study of Transfer Students.

 

 

An illustration that shows the Earth’s magnetosphere during a magnetic storm.

Researchers discover a new source of space weather – too close to home

An illustration that shows the Earth’s magnetosphere during a magnetic storm.

An illustration shows the Earth’s magnetosphere during a magnetic storm. At right, three satellites witnessed reconnection close to geosynchronous orbit where many other critical satellites reside. The red “X” identifies the reconnection site, and the yellow arrows indicate the direction of explosive outflows of energized particles toward and away from Earth. Earth-directed electrons (shown in red and pink) carry energy along magnetic field lines to power the aurora at Earth’s north and south poles. These energized electrons were detected by a weather satellite (center).

Beyond Earth’s atmosphere are swirling clouds of energized particles — ions and electrons — that emanate from the sun. This “solar wind” buffets the magnetosphere, the magnetic force field that surrounds Earth.

In much the same way winds and storms create weather in our atmosphere, strong gusts of solar wind penetrating the magnetosphere can generate magnetic storms with powerful electric currents that can impact our lives.

A new study by the NASA THEMIS mission team — led by Vassilis Angelopoulos, a UCLA professor of space physics — is the first to show that such storms can originate much closer to Earth than previously thought, overlapping with the orbits of critical weather, communications and GPS satellites. The team’s findings are published in the journal Nature Physics.

Magnetic storms can produce dazzling northern lights or hazardous particles careening toward spacecraft and astronauts, zapping them out of commission. Under certain conditions, magnetic storms can disable the electrical grid, disrupt radio communications and corrode pipelines, even creating extreme aurora visible close to the equator.

“By studying the magnetosphere, we improve our chances of dealing with the greatest hazard to humanity venturing into space: storms powered by the sun,” Angelopoulos said.

An incident that illustrates the dramatic power of magnetic storms occurred in 1921, when such a storm disrupted telegraph communications and caused power outages that resulted in a New York City train station burning to the ground. And in 1972 the Apollo 16 and 17 astronauts narrowly missed what could have been a lethal solar eruption. These incidents underscore the potential dangers that should be assessed as more humans venture into orbit. If a similar storm occurred today, a separate study estimated, economic losses in the U.S. due to electrical blackouts only could surpass $40 billion a day.

How electric currents in space influence the aurora and magnetic storms has been long debated in the space physics community. Because the storms occur so rarely and satellite coverage is sparse, it has been difficult for researchers to detect the dynamic process that powers those storms.

When solar wind magnetic energy is transferred into the magnetosphere, it builds up until it is converted into heat and particle acceleration through a process called magnetic reconnection. After decades of study, it is still unclear to researchers where exactly magnetic reconnection occurs during storms.

Recent observations by multiple satellites have shown that magnetic storms can be initiated by magnetic reconnection much closer to Earth than previously thought possible. The three NASA THEMIS satellites observed magnetic reconnection only about three to four Earth diameters away. The researchers did not expect this could happen in the comparatively stable magnetic field configuration near Earth.

Later, a weather satellite, which was nearer to Earth in geostationary orbit, detected energized particles associated with magnetic storms.

The weather satellite proved that this near-Earth reconnection stimulated ion and electron acceleration to high energies, posing a hazard to hundreds of satellites operating in this common orbit. Such particles can damage electronics and human DNA, increasing the risk of radiation poisoning and cancer for astronauts. Some particles can even enter the atmosphere and affect airline passengers.

“Only with such direct measurements of magnetic reconnection and its resulting energy flows could we convincingly prove such an unexpected mechanism of storm power generation,” said Angelopoulos, who is lead author of the paper. “Capturing this rare event, nearer to Earth than ever detected before, forces us to revise prior assumptions about the reconnection process.”

This discovery will ultimately help scientists refine predictive models of how the magnetosphere responds to solar wind, providing precious extra hours or even days to prepare satellites, astronauts and the energy grid for the next “big one” in space.

This article originally appeared in the UCLA Newsroom.

Photos of UCLA College professors Jose Rodriguez and Erik Petigura.

Two UCLA College faculty members awarded 2020 Sloan Research Fellowships

Photos of UCLA College professors Jose Rodriguez and Erik Petigura.

UCLA College professors Jose Rodriguez (left) and Erik Petigura (right).

Two young UCLA College professors, and two others, are among 126 scientists and scholars from more than 60 colleges and universities in the United States and Canada selected today to receive 2020 Sloan Research Fellowships. UCLA is tied for fifth — behind only Stanford, UC Berkeley, UC San Diego and the Massachusetts Institute of Technology — in the number of faculty honored this year by the Alfred P. Sloan Foundation, which selects early-career scientists and scholars who are rising stars of science.

“To receive a Sloan Research Fellowship is to be told by your fellow scientists that you stand out among your peers,” says Adam F. Falk, president of the Alfred P. Sloan Foundation. “A Sloan Research Fellow is someone whose drive, creativity and insight make them a researcher to watch.”

Since the first Sloan Research Fellowships were awarded in 1955, 165 UCLA faculty members have received Sloan Research Fellowships. UCLA College’s 2020 recipients are:

Erik Petigura

Petigura, an assistant professor of physics and astronomy in the UCLA College, studies exoplanets — planets orbiting stars other than the sun — using ground-based and space-based telescopes. “My passion for exoplanets is motivated by a deceptively simple, yet fundamental question: Why are we here?” said Petigura. “Our species has wrestled with this question since antiquity, and it resonates strongly with me.” Exoplanets offer the key avenue toward answering this question, as they inform the otherwise elusive physical processes that led to the formation of the solar system, the formation of the Earth and the origin of life. His group has shown that nearly every sun-like star has a planet between the size of Earth and Neptune — sizes not present in the solar system. “In other words, our solar system is not a typical outcome of planet formation, at least in that one key respect,” he said. As a Sloan Fellow, Petigura plans to study the origin, evolution and fate of these ubiquitous planets.

Jose Rodriguez

Rodriguez, an assistant professor of chemistry and biochemistry in the UCLA College, develops and applies new scientific methods in bio-imaging to determine, and provide a deep scientific understanding of, cellular and molecular structures and reveal undiscovered structures that influence chemistry, biology and medicine. His research combines computational, biochemical and biophysical experiments. His laboratory is working to explore the structures adopted by prions — a form of infectious protein that causes neurodegenerative disorders. Prion proteins, like the amyloid proteins associated with Alzheimer’s disease, form large clumps that damage and ultimately kill neurons in the brain. Among his awards and honors, Rodriguez won a 2019 Packard fellowship for Science and Engineering by the David and Lucile Packard Foundation; a 2018 Pew scholar in the biomedical sciences, a 2017 Searle Scholar and a 2017 Beckman Young Investigator by the Arnold and Mabel Beckman Foundation.

Winners of Sloan Research Fellowships receive a two-year, $75,000 award to support their research. The fellowships are intended to enhance the careers of exceptional young scientists and scholars in chemistry, computer science, economics, mathematics, computational and evolutionary molecular biology, neuroscience, ocean sciences and physics. The Sloan Foundation, which is based in New York, was established in 1934.

This article originally appeared in the UCLA Newsroom.

Photo of orbits of the G objects at the center of our galaxy

Astronomers discover class of strange objects near our galaxy’s enormous black hole

Photo of orbits of the G objects at the center of our galaxy

Orbits of the G objects at the center of our galaxy, with the supermassive black hole indicated with a white cross. Stars, gas and dust are in the background. Photo: Anna Ciurlo, Tuan Do/UCLA Galactic Center Group

Astronomers from UCLA’s Galactic Center Orbits Initiative have discovered a new class of bizarre objects at the center of our galaxy, not far from the supermassive black hole called Sagittarius A*. They published their research in the Jan. 16 issue of the journal Nature.

“These objects look like gas and behave like stars,” said co-author Andrea Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics and director of the UCLA Galactic Center Group.

The new objects look compact most of the time and stretch out when their orbits bring them closest to the black hole. Their orbits range from about 100 to 1,000 years, said lead author Anna Ciurlo, a UCLA postdoctoral researcher.

Ghez’s research group identified an unusual object at the center of our galaxy in 2005, which was later named G1. In 2012, astronomers in Germany made a puzzling discovery of a bizarre object named G2 in the center of the Milky Way that made a close approach to the supermassive black hole in 2014. Ghez and her research team believe that G2 is most likely two stars that had been orbiting the black hole in tandem and merged into an extremely large star, cloaked in unusually thick gas and dust.

“At the time of closest approach, G2 had a really strange signature,” Ghez said. “We had seen it before, but it didn’t look too peculiar until it got close to the black hole and became elongated, and much of its gas was torn apart. It went from being a pretty innocuous object when it was far from the black hole to one that was really stretched out and distorted at its closest approach and lost its outer shell, and now it’s getting more compact again.”

“One of the things that has gotten everyone excited about the G objects is that the stuff that gets pulled off of them by tidal forces as they sweep by the central black hole must inevitably fall into the black hole,” said co-author Mark Morris, UCLA professor of physics and astronomy. “When that happens, it might be able to produce an impressive fireworks show since the material eaten by the black hole will heat up and emit copious radiation before it disappears across the event horizon.”

But are G2 and G1 outliers, or are they part of a larger class of objects? In answer to that question, Ghez’s research group reports the existence of four more objects they are calling G3, G4, G5 and G6. The researchers have determined each of their orbits. While G1 and G2 have similar orbits, the four new objects have very different orbits.

Ghez believes all six objects were binary stars — a system of two stars orbiting each other — that merged because of the strong gravitational force of the supermassive black hole. The merging of two stars takes more than 1 million years to complete, Ghez said.

“Mergers of stars may be happening in the universe more often than we thought, and likely are quite common,” Ghez said. “Black holes may be driving binary stars to merge. It’s possible that many of the stars we’ve been watching and not understanding may be the end product of mergers that are calm now. We are learning how galaxies and black holes evolve. The way binary stars interact with each other and with the black hole is very different from how single stars interact with other single stars and with the black hole.”

Ciurlo noted that while the gas from G2’s outer shell got stretched dramatically, its dust inside the gas did not get stretched much. “Something must have kept it compact and enabled it to survive its encounter with the black hole,” Ciurlo said. “This is evidence for a stellar object inside G2.”

“The unique dataset that Professor Ghez’s group has gathered during more than 20 years is what allowed us to make this discovery,” Ciurlo said. “We now have a population of ‘G’ objects, so it is not a matter of explaining a ‘one-time event’ like G2.”

The researchers made observations from the W.M. Keck Observatory in Hawaii and used a powerful technology that Ghez helped pioneer, called adaptive optics, which corrects the distorting effects of the Earth’s atmosphere in real time. They conducted a new analysis of 13 years of their UCLA Galactic Center Orbits Initiative data.

In September 2019, Ghez’s team reported that the black hole is getting hungrier and it is unclear why. The stretching of G2 in 2014 appeared to pull off gas that may recently have been swallowed by the black hole, said co-author Tuan Do, a UCLA research scientist and deputy director of the Galactic Center Group. The mergers of stars could feed the black hole.

The team has already identified a few other candidates that may be part of this new class of objects, and are continuing to analyze them.

Ghez noted the center of the Milky Way galaxy is an extreme environment, unlike our less hectic corner of the universe.

“The Earth is in the suburbs compared to the center of the galaxy, which is some 26,000 light-years away,” Ghez said. “The center of our galaxy has a density of stars 1 billion times higher than our part of the galaxy. The gravitational pull is so much stronger. The magnetic fields are more extreme. The center of the galaxy is where extreme astrophysics occurs — the X-sports of astrophysics.”

Ghez said this research will help to teach us what is happening in the majority of galaxies.

Other co-authors include Randall Campbell, an astronomer with the W.M. Keck Observatory in Hawaii; Aurelien Hees, a former UCLA postdoctoral scholar, now a researcher at the Paris Observatory in France; and Smadar Naoz, a UCLA assistant professor of physics and astronomy.

The research is funded by the National Science Foundation, W.M. Keck Foundation and Keck Visiting Scholars Program, the Gordon and Betty Moore Foundation, the Heising-Simons Foundation, Lauren Leichtman and Arthur Levine, Jim and Lori Keir, and Howard and Astrid Preston.

In July 2019, Ghez’s research team reported on the most comprehensive test of Einstein’s iconic general theory of relativity near the black hole. They concluded that Einstein’s theory passed the test and is correct, at least for now.

► Watch a four-minute film about Ghez’s research

►View an animation below of the orbits of the G objects, together with the orbits of stars near the supermassive black hole. Credit: Advanced Visualization Lab, National Center for Supercomputing Applications, University of Illinois

This article originally appeared in the UCLA Newsroom.