Earth

The abrupt climate warming events that occurred in Greenland during the last glacial period occurred very close in time to other rapid climate change events seen in paleoclimate records from lower latitudes, according to a new study, which reveals a near-synchronous teleconnection of climate events spanning Earth's hemispheres. The new high-resolution paleoclimate chronology, which was derived from thin layers of sedimentary cave rocks from around the world, provides a framework to improve climate change models and constrain ice-core chronologies. This is important in the context of considering future abrupt climate change around the globe. Climate records from Greenland ice cores spanning the last glacial cycle (115,000 to 11,700 years ago) reveal a series of abrupt climate fluctuations between warm and cold conditions. These oscillations, also known as Dansgaard-Oeschger (DO) events, are characterized by an abrupt transition to a period of rapid warming, which is followed by a more gradual, and then abrupt, return to a cooler climate state. The oscillations occur quasi-periodically on a centennial- to millennial-scale. Outside of the Arctic, similar abrupt climate change events during the last glacial have also been identified in a host of other paleoclimate records from far-away regions across the globe. While the processes responsible for the abrupt transitions aren't well understood, they are thought to be linked. However, due to the lack of precise paleoclimate chronologies with comparable resolutions, determining if Greenland's DO events occurred at the same time as other abrupt climate changes elsewhere remains difficult. Ellen Corrick and colleagues compiled data from 63 published, high-resolution and precisely dated speleothem records, which describe the last glacial period in regions across the Northern Hemisphere mid-latitudes to the Southern Hemisphere sub-tropics. Using the dataset, Corrick et al. investigated the timing of 53 major and minor abrupt warming events and found that those recorded in Greenland's ice were synchronous with abrupt climate changes across the Asian Monsoon, South American Monsoon and European-Mediterranean regions. The findings suggest that abrupt Arctic warming events triggered rapid climate change on a global scale.

Abrupt climate changes during the Last Glacial Period, some 115,000 to 11,700 years ago, happened at the same time across a region extending from the Arctic to the Southern Hemisphere subtropics, new research has revealed.

The study, led by University of Melbourne PhD student Ellen Corrick and published today in the journal, Science, found that rapid warming events over Greenland were linked to simultaneous temperature increases across continental Europe, and changes in rainfall in the Asian and South American monsoon regions.

"Some of the largest and most abrupt climate changes in Earth's geological recent past occurred during the Last Glacial Period, a cold interval that extended between 115,000 and 11,700 years ago," Ms Corrick said.

Greenland ice cores recorded more than 25 abrupt warming episodes during this period. These so called 'Dansgaard-Oeschger events' were associated with increases in air temperature over Greenland of up to 16°Celsius, sometimes in a matter of a few decades.

Researchers say the findings provide important information for testing numerical models used to predict future climate changes and demonstrate that profound climate changes can occur simultaneously, highlighting the unstable nature of the climate system.

Co-author, University of Melbourne Associate Professor Russell Drysdale, said: "Demonstrating synchrony in the climate response across such a broad region marks a major advance in the study of Dansgaard-Oeschger events. It allows scientists to improve understanding of how the events are propagated globally via the ocean and atmosphere system."

The research team, which involved scientists from Denmark, the UK, Germany, China, France and Switzerland, collated 63 individual climate records derived from stalagmites collected from caves across Europe, Asia and South America. The records represent over 20 years' worth of published research from scientific teams around the world.

Stalagmites - a type of cave mineral formation - preserve information on regional temperature and rainfall as they grow. Crucially, they can be dated very precisely, allowing the timing of climate events to be compared between records from different regions.

University of Melbourne Geochronologist Dr John Hellstrom, said that resolving the issue of timing has proved difficult because precisely dated records of past climate are required to determine exactly when the events took place.

"Such records are relatively rare, and it is only now that we have enough high-quality records to actually answer the question of synchrony," Dr Hellstrom said.

According to co-author Professor Eric Wolff from the University of Cambridge, the findings resolve a long-standing dilemma within the paleoclimate community, who study ancient climates.

"They provide confirmation of a persistent but, until now, unsubstantiated assumption that climate changes between the tropics and the Arctic were synchronous."

ITHACA, N.Y. - As with actors and opera singers, when measuring magnetic fields it helps to have range.

Cornell researchers used an ultrathin graphene "sandwich" to create a tiny magnetic field sensor that can operate over a greater temperature range than previous sensors, while also detecting miniscule changes in magnetic fields that might otherwise get lost within a larger magnetic background.

Hall-effect sensor
Provided

Researchers led by Katja Nowack, assistant professor of physics, created this micron-scale Hall-effect sensor by sandwiching graphene between sheets of hexagonal boron nitride, resulting in a device that operates over a greater temperature range than previous Hall sensors.

The group's paper, "Magnetic Field Detection Limits for Ultraclean Graphene Hall Sensors," published Aug. 20 in Nature Communications.

The team was led by Katja Nowack, assistant professor of physics in the College of Arts and Sciences and the paper's senior author.

Nowack's lab specializes in using scanning probes to conduct magnetic imaging. One of their go-to probes is the superconducting quantum interference device, or SQUID, which works well at low temperatures and in small magnetic fields.

"We wanted to expand the range of parameters that we can explore by using this other type of sensor, which is the Hall-effect sensor," said doctoral student Brian Schaefer, the paper's lead author. "It can work at any temperature, and we've shown it can work up to high magnetic fields as well. Hall sensors have been used at high magnetic fields before, but they're usually not able to detect small magnetic field changes on top of that magnetic field."

The Hall effect is a well-known phenomenon in condensed matter physics. When a current flows through a sample, it is bent by a magnetic field, creating a voltage across both sides of the sample that is proportional to the magnetic field.

Hall-effect sensors are used in a variety of technologies, from cellphones to robotics to anti-lock brakes. The devices are generally built out of conventional semiconductors like silicon and gallium arsenide.

Nowack's group decided to try a more novel approach.

The last decade has seen a boom in uses of graphene sheets - single layers of carbon atoms, arranged in a honeycomb lattice. But graphene devices often fall short of those made from other semiconductors when the graphene sheet is placed directly on a silicon substrate; the graphene sheet "crumples" on the nanoscale, inhibiting its electrical properties.

Nowack's group adopted a recently developed technique to unlock graphene's full potential - sandwiching it between sheets of hexagonal boron nitride. Hexagonal boron nitride has the same crystal structure as graphene but is an electrical insulator, which allows the graphene sheet to lie flat. Graphite layers in the sandwich structure act as electrostatic gates to tune the number of electrons that can conduct electricity in the graphene.

The sandwich technique was pioneered by co-author Lei Wang, a former postdoctoral researcher with the Kavli Institute at Cornell for Nanoscale Science. Wang also worked in the lab of co-senior author Paul McEuen, the John A. Newman Professor of Physical Science and co-chair of the Nanoscale Science and Microsystems Engineering (NEXT Nano) Task Force, part of the provost's Radical Collaboration initiative.

"The encapsulation with hexagonal boron nitride and graphite makes the electronic system ultraclean," Nowack said. "That allows us to work at even lower electron densities than we could before, and that's favorable for boosting the Hall-effect signal we are interested in."

The researchers were able to create a micron-scale Hall sensor that functions as well as the best Hall sensors reported at room temperature while outperforming any other Hall sensor at temperatures as low as 4.2 kelvins (or minus 452.11 degrees Fahrenheit).

The graphene sensors are so precise they can pick out tiny fluctuations in a magnetic field against a background field that is larger by six orders of magnitude (or a million times its size). Detecting such nuances is a challenge for even high-quality sensors because in a high magnetic field, the voltage response becomes nonlinear and therefore more difficult to parse.

Nowack plans to incorporate the graphene Hall sensor into a scanning probe microscope for imaging quantum materials and exploring physical phenomena, such as how magnetic fields destroy unconventional superconductivity and the ways that current flows in special classes of materials, such as topological metals.

"Magnetic field sensors and Hall sensors are important parts of many real-world applications," Nowack said. "This work puts ultraclean graphene really on the map for being a superior material to build Hall probes out of. It wouldn't be really practical for some applications because it's hard to make these devices. But there are different pathways for materials growth and automated assembly of the sandwich that people are exploring. Once you have the graphene sandwich, you can put it anywhere and integrate it with existing technology."

There are well documented risk factors associated with developing substance use disorder across all age groups. A recent study from IUPUI found those risk factors affect age groups differently and proposes a primary prevention strategy for substance use disorder that is individualized for people within defined age groups.

The study proposes a primary prevention strategy for SUD that is individualized for people within defined age groups. This approach is in contrast to current strategies that involve targeting individual substances being abused within a certain community or population.

"We need to start approaching the problem of substance use disorder from the basis of what makes individuals abuse one or more substances instead of what substances are abused in a community," said Eric Afuseh, clinical assistant professor at the IUPUI School of Nursing. "The current prevention approach does not consider the fact that what makes a child develop a substance use disorder is different from what will cause an adult or older adult to abuse the same substance."

The study, published in Substance Abuse Treatment, Prevention, and Policy, looked at more than 300 written articles, published between 1989 and 2019, to identify risk factors for substance use disorder among children, young adults, adults, and older adults. Researchers analyzed similarities and differences in risk factors across life stages and found that across all age groups, risk factors for developing SUD included adverse childhood experiences, trauma, chronic health diseases, environmental factors, family history, social determinants, and grief and loss.

However, despite the similarities, the contextual factors and life challenges associated with these risks varied according to life stages.

For children under 18, the study found risk factors included adverse childhood experiences and trauma, peer pressure, participation in organized athletics and a family history of misuse. For young adults (age 18-25), who may or may not have had childhood risk factors, the added stress of adulthood, latent family history, lack of positive parental role models, lack of employment, and academic stress were added risk factors.

Major risk factors for adults age 26-64, according to the study, are related to family life and career. Different careers associated with substance use disorders in adults include high-stress jobs and heavily physical jobs such as healthcare, military service, and law. While risk factors for adults over 65 are similar to those in younger groups, there are also unique age-related risk factors such as experiencing grief and loss more frequently, due to deaths among family and friends, and a greater tendency for chronic physical illnesses, such as arthritis and other chronic pain conditions, which increases the likelihood of misusing substances to relieve pain.

To create preventions that work, Afuseh's team suggests screenings based on the identified risk factors in each age group. Screening results can be used to customize education and empowerment interventions such as mentoring, social media, targeted communications, workplace orientation information and more.

The age-based approach, Afuseh said, not only allows prevention methods to be individualized, it also takes off some of the burden off of healthcare workers, as anyone can initiate it including parents, educators and employers.

"Federal, state and local agencies have put resources and processes in place to address substance use disorders at different levels of the disease continuum," Afuseh said. "But those strategies tend to address specific substances at the population level. To be truly effective, we need to account for the unique developmental factors and life stressors in different age groups, the potential misuse of more than one substance at a time and the multiple risk factors for developing a substance use disorder."

Afuseh has proposed age-related screening, education and empowerment as a framework for primary prevention of SUD. Researchers will now work to design and test screening tools that can be administered to individuals of different age groups with recommended strategies to address each screening result.

NASA provided a series of photos of Hurricane Genevieve as it affected Mexico's southern Baja California peninsula. An astronaut aboard the International Space Station provided wide-angle photos of Genevieve, showing the size of the storm. Warnings and watches are in effect on Aug. 20.

International Space Station Astronaut Chris Cassidy snapped photos of the Eastern Pacific Ocean's Hurricane Genevieve on Aug 19, 2020 at 4 p.m. EDT. The photos revealed a clear eye surrounded by a ring of powerful thunderstorms. At the time of the photo Genevieve's tropical-storm force winds extended out 280 miles. By Aug. 20 as the storm weakened, its wind field expanded and hurricane-force winds extended outward up to 30 miles (45 km) from the center and tropical-storm-force winds extended outward up to 115 miles (185 km).

On Aug. 20, Genevieve was moving in a northerly direction, paralleling the coast of Baja California Sur.

Warnings and Watches on Aug. 20

On Thursday, August 20, 2020, NOAA's National Hurricane Center (NHC) posted a Tropical Storm Warning for Mexico's Baja California peninsula from Los Barriles to Cabo San Lazaro. A Tropical Storm Watch is in effect for the east coast of the Baja California peninsula from Los Barriles to La Paz. At 11 a.m. EDT (1500 UTC), the NHC reported, "Tropical storm conditions have already been occurring along the southern tip of the Baja California peninsula since last night, and these conditions continue to spread northward over the Southern Baja California peninsula, especially over higher terrain."

Genevieve on Thursday, August 20

At 11 a.m. EDT (1500 UTC), the center of Hurricane Genevieve was located near latitude 23.3 degrees north and longitude 111.4 degrees west. That is about 100 miles (160 km) west-northwest of the southern tip of Baja California and about 120 miles (190 south-southeast of Cabo San Lazaro, Mexico. Genevieve was moving toward the northwest near 12 mph (19 kph) and this motion is expected to continue through Saturday.

Maximum sustained winds are near 75 mph (120 kph) with higher gusts.  Further gradual weakening is expected today and through the weekend.  However, Genevieve is expected to remain a hurricane through much of today while it passes just to the southwest and west of the southern Baja California peninsula. The estimated minimum central pressure is 984 millibars.

Baja California Hazards

NHC noted the Baja is facing strong winds, heavy rainfall, and large ocean swells. "Tropical storm conditions will spread northward within the warning area in the southern Baja California peninsula through today and may linger into tonight.  Tropical storm conditions are possible within the watch area through the early afternoon, especially over higher terrain.

Genevieve is expected to produce additional rainfall amounts of 2 to 4 inches across southern Baja California Sur, with isolated storm totals of 12 inches across far southern Baja California Sur. This rainfall may lead to life-threatening flash flooding and mudslides.

Large swells produced by Genevieve are affecting portions of the west-central coast of Mexico and are spreading northward along the coast of the Baja California peninsula.  These swells are likely to cause life-threatening surf and rip current conditions."

Genevieve's Forecast Track

The National Hurricane Center forecast said the center of Genevieve is expected to pass just to the southwest and west of the southern portion of the Baja California peninsula today (Aug. 20), and move away from the peninsula on Friday, Aug. 21.

NASA Researches Tropical Cyclones

Hurricanes/tropical cyclones are the most powerful weather events on Earth. NASA's expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

For more than five decades, NASA has used the vantage point of space to understand and explore our home planet, improve lives and safeguard our future. NASA brings together technology, science, and unique global Earth observations to provide societal benefits and strengthen our nation. Advancing knowledge of our home planet contributes directly to America's leadership in space and scientific exploration.

La Jolla - Scientists at Scripps Research and Calibr, the institute’s drug discovery division, have discovered a molecule that can activate a natural immune-boosting protein called STING to help patients fight cancer.

The findings, which exemplify the interplay between Calibr and the basic science that makes Scripps Research a renowned center of innovation, mark a key advance in the field of oncology, as the STING protein is known for its strong antitumor properties.

STING (short for STimulator of INterferon Genes) marshals the immune system against viral and cancerous invaders and, because of its role in promoting antitumor immunity, has garnered enthusiastic interest from drug developers.

However, STING’s natural activators in the body are unstable DNA-related molecules that do not last long in the bloodstream. That has hindered the development of treatments based on them, and has prompted a search for a hardier STING-activating small molecule—one that can circulate in the blood and work against tumors “systemically,” wherever they may exist in the body.

The Scripps Research and Calibr scientists – whose findings were published in Science on August 20 – characterized a set of small molecules discovered and developed at Calibr, and extensively studied in the Scripps Research labs of Luke Lairson, PhD, and John Teijaro, PhD. The Calibr team, led by Mike Petrassi, PhD, vice president of Medicinal Chemistry at Calibr, brought to bear medicinal chemistry and pharmacology expertise to create an optimized drug candidate that, when delivered systemically into mice, greatly reduced the growth of an aggressive form of melanoma.

The discovery raises the possibility of a safe and effective drug that could activate STING and suppress a wide range of cancers.

“A systemic STING-activating molecule could have considerable utility, and not only as a therapeutic for cancer and infectious disease, but also as a probe for studying STING-dependent antitumor immunity and a host of other STING-related biological processes,” says Lairson, a co-senior author and associate professor in the Department of Chemistry at Scripps Research.

The scientists found that their optimized STING-activator, which they named SR-717, appears to activate the STING protein in the same way as its natural activators in the body. Using X-ray crystallography to image the interaction at atomic scale, they showed that both SR-717 and a known natural activator bind to the same site on STING and induce the same shape-change in the protein.

In an animal model of aggressive melanoma, SR-717 dramatically suppressed tumor growth, prevented metastasis, induced the presentation of tumor molecules to the immune system, and robustly boosted levels around tumors of CD8+ T cells and NK cells—both of which are known to be among the immune system’s heaviest antitumor weapons. At this effective dose, there was no evidence of significant adverse side effects on the animals.

The researchers are continuing to study SR-717, with the hope of developing it into a new anticancer treatment that could be used alone or in combination with other treatments.

La Jolla - Scientists at Scripps Research and Calibr, the institute’s drug discovery division, have discovered a molecule that can activate a natural immune-boosting protein called STING to help patients fight cancer.

The findings, which exemplify the interplay between Calibr and the basic science that makes Scripps Research a renowned center of innovation, mark a key advance in the field of oncology, as the STING protein is known for its strong antitumor properties.

STING (short for STimulator of INterferon Genes) marshals the immune system against viral and cancerous invaders and, because of its role in promoting antitumor immunity, has garnered enthusiastic interest from drug developers.

However, STING’s natural activators in the body are unstable DNA-related molecules that do not last long in the bloodstream. That has hindered the development of treatments based on them, and has prompted a search for a hardier STING-activating small molecule—one that can circulate in the blood and work against tumors “systemically,” wherever they may exist in the body.

The Scripps Research and Calibr scientists – whose findings were published in Science on August 20 – characterized a set of small molecules discovered and developed at Calibr, and extensively studied in the Scripps Research labs of Luke Lairson, PhD, and John Teijaro, PhD. The Calibr team, led by Mike Petrassi, PhD, vice president of Medicinal Chemistry at Calibr, brought to bear medicinal chemistry and pharmacology expertise to create an optimized drug candidate that, when delivered systemically into mice, greatly reduced the growth of an aggressive form of melanoma.

The discovery raises the possibility of a safe and effective drug that could activate STING and suppress a wide range of cancers.

“A systemic STING-activating molecule could have considerable utility, and not only as a therapeutic for cancer and infectious disease, but also as a probe for studying STING-dependent antitumor immunity and a host of other STING-related biological processes,” says Lairson, a co-senior author and associate professor in the Department of Chemistry at Scripps Research.

The scientists found that their optimized STING-activator, which they named SR-717, appears to activate the STING protein in the same way as its natural activators in the body. Using X-ray crystallography to image the interaction at atomic scale, they showed that both SR-717 and a known natural activator bind to the same site on STING and induce the same shape-change in the protein.

In an animal model of aggressive melanoma, SR-717 dramatically suppressed tumor growth, prevented metastasis, induced the presentation of tumor molecules to the immune system, and robustly boosted levels around tumors of CD8+ T cells and NK cells—both of which are known to be among the immune system’s heaviest antitumor weapons. At this effective dose, there was no evidence of significant adverse side effects on the animals.

The researchers are continuing to study SR-717, with the hope of developing it into a new anticancer treatment that could be used alone or in combination with other treatments.

“Antitumor activity of a systemic STING-activating non-nucleotide cGAMP mimetic” was written by Emily Chin, Chenguang Yu, Vincent Vartabedian, Ying Jia, Manoj Kumar, Ana Maria Gamo Albero, William Vernier, Sabrina Ali, Mildred Kissai, Daniel Lazar, Nhan Nguyen, Laura Pereira, Brent Benish, Ashley Woods, Sean Joseph, Alan Chu, Kristen Johnson, Philipp Sander, Francisco Martinez-Pena, Eric Hampton, Travis Young, Dennis Wolan, Arnab Chatterjee, Peter Schultz, Michael Petrassi, John Teijaro, and Luke Lairson, all of Scripps Research during the study.

 CLEVELAND--For more than 500 years, humans have mastered the art of refracting light by shaping glass into lenses, then bending or combining those lenses to amplify and clarify images either close-up and far-off. 
 

But in the last decade or so, a group led by scientist Federico Capasso at Harvard University has begun to transform the field of optics by engineering flat optics metasurfaces, employing an array of millions of tiny microscopically thin and transparent quartz pillars to diffract and mold the flow of light in much the same way as a glass lens, but without the aberrations that naturally limit the glass.
 

The technology was selected as among the Top 10 Emerging Technologies by the World Economic Forum (WEF) in 2019, which remarked that these increasingly smaller, clearer lenses would soon begin to be seen in camera phones, sensors, optical-fiber lines and medical-imaging devices, such as endoscopes.

"Making the lenses used by mobile phones, computers and other electronic devices smaller has been beyond the capabilities of traditional glass cutting and glass curving techniques," according to the WEF. "...These tiny, thin, flat lenses could replace existing bulky glass lenses and allow further miniaturization in sensors and medical imaging devices."

Making metalenses 'reconfigurable'

Now, Case Western Reserve University physics professor Giuseppe Strangi and collaborators at Harvard have taken a step toward making these "metalenses" even more useful--by making them reconfigurable.
 

They did this by harnessing nanoscale forces to infiltrate liquid crystals between those microscopic pillars, allowing them to shape and diffract the light in completely new ways--"tuning" the focusing power, Strangi said.

Liquid crystals are especially useful because can be manipulated thermally, electrically, magnetically or optically, which creates the potential for the flexible or reconfigurable lenses.
 

"We believe that this holds the promise to revolutionize optics as we know it since the 16th century," said Strangi, whose Nanoplasm Lab at Case Western Reserve investigates "extreme optics" and the "interaction of light and matter at nanoscale," among other matters.
 

Until recently, once a glass lens was shaped into a rigid curve, it could only bend the light in one way, unless combined with other lenses or physically moved, Strangi said.

Metalenses changed that, since they allow to engineer the wavefront by controlling phase, amplitude and polarization of the light.

Now, by controlling the liquid crystal, the researchers have been able move these new class of metalenses towards new scientific and technological endeavors to generate reconfigurable structured light .

"This is just the first step, but there are many possibilities for using these lenses, and we have already been contacted by companies interested in this technology," Strangi said.
 

The paper announcing the breakthrough was published in early August by the Proceedings of the National Academy of Sciences. 
 

Strangi collaborated with several other researchers in the United States and Europe, including fellow Case Western Reserve researchers Andrew Lininger and Jonathan Boyd; Giovanna Palermo of Universita' della Calabria in Italy; and Capasso, Alexander Zhu and Joon-Suh Park of the John A. Paulson School of Engineering and Applied Sciences at Harvard University.

Lininger said part of the problem with current applications of metasurfaces is that their shape is fixed at the point of production, but "by enabling reconfigurability in the metasurface, these limitations can be overcome."

Capasso, who pioneered the flat optics research field and in 2014 first published research on metalenses, credited Strangi for the idea to infiltrate the metalenses with liquid crystals and said this innovation represents a step toward even bigger things.

"Our ability to reproducibly infiltrate with liquid crystals state-of-the art metalenses made of over 150 million nanoscale diameter glass pillars and to significantly change their focusing properties is a portent of the exciting science and technology I expect to come out of reconfigurable flat optics in the future," Capasso said.

Light is notoriously fast. Its speed is crucial for rapid information exchange, but as light zips through materials, its chances of interacting and exciting atoms and molecules can become very small. If scientists can put the brakes on light particles, or photons, it would open the door to a host of new technology applications.

Now, in a paper published on Aug. 17, in Nature Nanotechnology, Stanford scientists demonstrate a new approach to slow light significantly, much like an echo chamber holds onto sound, and to direct it at will. Researchers in the lab of Jennifer Dionne, associate professor of materials science and engineering at Stanford, structured ultrathin silicon chips into nanoscale bars to resonantly trap light and then release or redirect it later. These "high-quality-factor" or "high-Q" resonators could lead to novel ways of manipulating and using light, including new applications for quantum computing, virtual reality and augmented reality; light-based WiFi; and even the detection of viruses like SARS-CoV-2.

"We're essentially trying to trap light in a tiny box that still allows the light to come and go from many different directions," said postdoctoral fellow Mark Lawrence, who is also lead author of the paper. "It's easy to trap light in a box with many sides, but not so easy if the sides are transparent - as is the case with many Silicon-based applications."

Make and manufacture

Before they can manipulate light, the resonators need to be fabricated, and that poses a number of challenges.

A central component of the device is an extremely thin layer of silicon, which traps light very efficiently and has low absorption in the near-infrared, the spectrum of light the scientists want to control. The silicon rests atop a wafer of transparent material (sapphire, in this case) into which the researchers direct an electron microscope "pen" to etch their nanoantenna pattern. The pattern must be drawn as smoothly as possible, as these antennas serve as the walls in the echo-chamber analogy, and imperfections inhibit the light-trapping ability.

"High-Q resonances require the creation of extremely smooth sidewalls that don't allow the light to leak out," said Dionne, who is also Senior Associate Vice Provost of Research Platforms/Shared Facilities. "That can be achieved fairly routinely with larger micron-scale structures, but is very challenging with nanostructures which scatter light more."

Pattern design plays a key role in creating the high-Q nanostructures. "On a computer, I can draw ultra-smooth lines and blocks of any given geometry, but the fabrication is limited," said Lawrence. "Ultimately, we had to find a design that gave good-light trapping performance but was within the realm of existing fabrication methods."

High quality (factor) applications

Tinkering with the design has resulted in what Dionne and Lawrence describe as an important platform technology with numerous practical applications.

The devices demonstrated so-called quality factors up to 2,500, which is two orders of magnitude (or 100 times) higher than any similar devices have previously achieved. Quality factors are a measure describing resonance behavior, which in this case is proportional to the lifetime of the light. "By achieving quality factors in the thousands, we're already in a nice sweet spot from some very exciting technological applications," said Dionne.

For example, biosensing. A single biomolecule is so small that it is essentially invisible. But passing light over a molecule hundreds or thousands of times can greatly increase the chance of creating a detectable scattering effect.

Dionne's lab is working on applying this technique to detecting COVID-19 antigens - molecules that trigger an immune response - and antibodies - proteins produced by the immune system in response. "Our technology would give an optical readout like the doctors and clinicians are used to seeing," said Dionne. "But we have the opportunity to detect a single virus or very low concentrations of a multitude of antibodies owing to the strong light-molecule interactions." The design of the high-Q nanoresonators also allows each antenna to operate independently to detect different types of antibodies simultaneously.

Though the pandemic spurred her interest in viral detection, Dionne is also excited about other applications, such as LIDAR - or Light Detection and Ranging, which is laser-based distance measuring technology often used in self-driving vehicles - that this new technology could contribute to. "A few years ago I couldn't have imagined the immense application spaces that this work would touch upon," said Dionne. "For me, this project has reinforced the importance of fundamental research - you can't always predict where fundamental science is going to go or what it's going to lead to, but it can provide critical solutions for future challenges."

This innovation could also be useful in quantum science. For example, splitting photons to create entangled photons that remain connected on a quantum level even when far apart would typically require large tabletop optical experiments with big expensive precisely polished crystals. "If we can do that, but use our nanostructures to control and shape that entangled light, maybe one day we will have an entanglement generator that you can hold in your hand," Lawrence said. "With our results, we are excited to look at the new science that's achievable now, but also trying to push the limits of what's possible."

It's probably quite easy to relate to. You're in a lecture or meeting, avidly taking notes and engaged in the topic. You're alert and aware of what's being discussed, keen to absorb as much as you can. And then, suddenly, your thoughts drift away. You stop hearing what's being said or seeing what's being shown. You become drowsy, your eyelids start to droop, and your mind switches off.

Although this scenario is familiar to many people, the reason behind why our brains do this is not properly understood. This is mainly because many different brain structures regulate our attention span and one of them is in layer 6 - the deepest layer in the cortex. The cortex, or cerebral cortex, is the outermost part of the brain in humans and other mammals. It is composed of functionally specialized and highly interconnected sensory, motor and association areas. Abstract thinking, an internal model of the outside world, and conscious perception all arise from this part of the brain.

"We know layer 6 of the cortex regulates how we are connected to the external world in a behavior state-related manner. It's involved in why we are fully aware in some situations and why our attention suddenly goes when we become drowsy," explained Dr. Sigita Augustinaite, from the Optical Neuroimaging Unit at the Okinawa Institute of Science and Technology Graduate University (OIST). "But it's a very difficult area of the brain to study."

For this research, which was published in Current Biology, Dr. Augustinaite worked with Professor Bernd Kuhn, who leads the Unit. They used a powerful microscopy technique - two-photon imaging - to examine the neuronal activity of visual cortex layer 6 in mice. This was the first time that layer 6 neurons had been studied with subjects that were awake and behaving.

Neurons are specialized cells, which transmit information to other nerve cells and muscles around the body. Within the brain, they form networks and communicate with each other via electrochemical signals. Given their importance, finding out more about their activity is vital for understanding how our brains work.

In each experiment, the mouse was placed in a fixed yet comfortable position and periodically shown different kinds of visual stimuli. It had the freedom to run, sit, groom itself and even sleep, all while hours of recordings were being taken from deep within its brain with cellular resolution. To determine its alertness, the researchers also recorded the electrical activity - or electroencephalogram - in the brain of the mouse, as well as its running speed and pupil size. The result was the ability to observe the activity of hundreds of individual neurons at once in response to different sensory conditions whilst the mouse was in different behavioral states.

The researchers found three distinct populations of neurons that reacted differently to the visual stimulation. Around one-third of the neurons were classed as visual stimulus activated (VSA) neurons. These were inactive when there were no visual stimuli but were activated when the mouse was shown a stimulus. Other neurons had the opposite reaction. They were spontaneously active without a visual stimulus but, once a stimulus was shown, the activity dropped away. These were classed as visual stimulus suppressed (VSS) neurons.

There was also a population of quiet neurons. These were neurons that didn't show any activity during this experiment. But, as Dr. Augustinaite explained, they might simply have shown no activity because the right kind of stimuli wasn't being presented to activate them. "There's a possibility that if the right stimuli were shown, then these so-called quiet neurons would have started acting as VSA neurons."

The majority of VSA and VSS neurons were most active when the mouse was most alert, and their activity gradually decreased as the mouse became sleepier. However, this was not always the case. Some neurons, especially among the VSS population, were most active during low alertness - when the mouse was drowsy or asleep. And interestingly, while many neurons did not discriminate between locomotion and stationary states, others did. Some neurons were only active during locomotion, whilst others were only active during stationary periods. In fact, if there's one thing this research has shown, it's that there's no constant. Rather, the neurons in layer 6 are diverse and dynamic.

"This is how we think layer 6 regulates what's happening," Dr. Augustinaite said. "The activity of these different populations of neurons complements each other."

For example, if there's a flow of visual information, VSA neurons send information outside of the cortex to other parts of the brain. But if it's dark, these sub-cortical areas still need to know what's happening in the cortex. So, the VSS neurons take over. This activity of layer 6 neurons regulates the information flow from the sensory organs to the cortex and is therefore one of the key factors that makes one pay attention or lose focus.

There's still a lot of research to be done in layer 6 to determine exactly how this circuit contributes to our attention spans and to different disorders, such as attention deficit, autism or schizophrenia, but Dr. Augustinaite emphasized that if we want to understand what's happening in our mind, then we must work with awake and behaving subjects. "This is the first-time layer 6 was investigated with this method."

Researchers from Tohoku University's Graduate School of Engineering have discovered a novel iron-based superelastic alloy (SEA) capable of withstanding extreme temperatures -both high and low.

SEAs are found in a wide variety of commercial applications because of their superelasticity, allowing them to regain their original shape. Superelasticity occurs when the metal undergoes deformation at the point known as critical stress.

Generally, SEAs have a positive temperature dependence; the critical stress increases as the temperature rises. Conventional metal-based SEAs such as Ti-Ni, cannot be used at temperatures lower than -20C or higher than 80C and are costly to make. This limits their application to the form of thin wires or tubes.

Associate Professor at Tohoku University, Toshihiro Omori and his team developed an iron-based SEA system, known as Fe-Mn-Al-Cr-Ni. This cost-effective SEA can also operate at a much wider temperature range.

A significant advantage of the new SEA is its controllable temperature dependence. Increasing the amount of Chromium allowed the researchers to change the temperature dependence from a positive to a negative. Balancing the Chromium content resulted in zero temperature dependence with the critical stress remaining almost constant at various temperatures.

The discovery possesses wide-spread application for outer-space exploration given the large temperature fluctuations that occur," says Professor Omori."

Omori points to the fact that NASA is developing a superelastic tire that can withstand excessive deformation for Moon and Mars missions. The temperature differences between night and day on the Moon and Mars are -170C to 120C and -150C to 20C respectively.

"Yet, the new, SEA's usage does not stop there." Professor Omori adds, "It can potentially be used in tension braces in buildings or column elements in bridges - providing greater resistance to earthquakes."

The discovery possesses wide-spread application for outer-space exploration given the large temperature fluctuations that occur," says Professor Omori."

Omori points to the fact that NASA is developing a superelastic tire that can withstand excessive deformation for Moon and Mars missions. The temperature differences between night and day on the Moon and Mars are -170C to 120C and -150C to 20C respectively.

"Yet, the new, SEA's usage does not stop there." Professor Omori adds, "It can potentially be used in tension braces in buildings or column elements in bridges - providing greater resistance to earthquakes."

Scientists at the University Bath in the UK have discovered a series of protein structures that are thought to be highly relevant to the onset of Parkinson's disease. It is hoped that further analysis of these structures will open up a new avenue for potential treatment for a disease that is the fastest growing neurological condition in the world, with no cure currently available.

According to Parkinson's UK, more than 1 million people in the UK are affected by the disease - either by living with the condition, or as a friend, colleague, or family member of someone who is. Latest estimates show that in 2020, around 145,000 people live with a Parkinson's diagnosis in the UK.

The disease is characterised by a specific protein 'misfolding', where it becomes distorted and then malfunctions. The protein which researchers at Bath have studied - alpha-synuclein (αS) - is abundant in all human brains. After misfolding, it accumulates in large masses, known as Lewy bodies. These masses consist of slender αS fibres that are toxic to dopamine-producing brain cells, causing them to die. It is this drop in dopamine that triggers the symptoms of Parkinson's Disease.

There has been much research into αS structure and the role it plays in Parkinson's, however virtually all studies have taken place in laboratory test tubes, where the protein is purified from bacteria and studied in isolation. Research of this kind often overlooks the fact that in the living brain, αS fibres form in the presence of 'phospholipids' - large fatty substances that make up cell membranes and play an essential role in living cells, both in their structure and metabolism.

In the new Bath study, published in Nature Partner Journal - Parkinson's disease, Professor Jody Mason and his team from the Department of Biology & Biochemistry examined how αS misfolds in the presence of phospholipids. They discovered a series of misfolded protein structures that have never been observed before. These αS fibres were larger than any previously reported and took on a striking variety of shapes. Some formed flat ribbons, others appeared as long, wave-like helices, while others still were more compact and bulkier.

The Bath researchers hope their discovery will mark the start of a new era in Parkinson's research. Their work lays the foundation for detailed analysis of misfolded αS fibres. Once the structure of these fibres is better understood, scientists will be able to investigate which versions are disease-causing and which are not. From here, they will be able to test drugs against pathogenic forms. This will constitute a major step forward in finding a cure for Parkinson's and other neurological conditions.

"We know that these misfolded proteins are heavily implicated in Parkinson's disease," said Professor Mason. "What's more, alpha-synuclein is known to be important in neurotransmission and in cell signalling. Given its interaction with brain cell membranes, the discovery of these structures in the presence of phospholipids may have far-reaching implications in our quest to find a disease-causing form of the protein."

The research charity Parkinson's UK has invested over £3.5 million in understanding the role played in the brain by αS. It recognises that unlocking the secrets of this protein could hold the key to finding a cure for the condition.

Dr Beckie Port, research manager at Parkinson's UK, said: "Alpha-synuclein is known to form different structures, and researchers have become increasingly interested in which forms of the protein may be toxic, and linked to the spread and loss of brain cells in Parkinson's - this is essential in order to develop treatments that target the right form of the protein.

"By advancing our understanding of the different structures of the protein that are likely to be present inside brain cells, this University of Bath study helps pave the way for developing treatments that may one day stop the progression of Parkinson's."

Phenology represents the seasonal dynamics of vegetation, and is an important indicator of local and regional climate change. With stronger warming trend at higher latitudes, the seasonality of vulnerable Arctic tundra is more sensitive. Many studies have reported advances in the start of growing season (SOS) in Northern Hemisphere, however, a delayed trend in SOS were reported in some recent studies.

A new study, published in Science China Earth Sciences, showed the temporal and spatial variations of the spring phenology at 29 sites in the Arctic tundra region using multiple remote sensing indices and ground observations from 2000 to 2018. The study was led by scientists from the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences.

"Due to the restrictions of the environment and equipment conditions, there are fewer ground observation sites in high-latitude regions than in low- and mid-latitude regions." said Jiangshan Zheng, first author of this study. In this study, scientists used data from ground observations and remote sensing to analyze spatial and temporal variation of tundra SOS. The multi-source and multi-scale data are used to ensure the data reliability.

"The estimated SOS usually differs among the various data sources, because temporal and spatial scales of observations and methods are different." said Zheng. "But we found that the SOS derived from remote sensing indices was consistent with ground observations in inferring latitudinal gradient and interannual variation of SOS."

According to this study, the SOS of almost all tundra types was delayed after 2016. High Arctic vegetation showed a stronger SOS delay trend than low Arctic vegetation in the past two decades.

"The spring phenology change in the Arctic tundra is driven by many environmental factors. The warming interval, spring frost, or reductions in winter chilling can lead to delayed SOS" said Dr. Xiyan Xu, one of the authors of this study.

"Under climate warming in Arctic, vegetation growth in the High Arctic is easily restricted by soil moisture because of dry and barren soils. While in the Low Arctic, soils contain more moisture facilitates mosses and lichens to utilize carbon, nitrogen, and other nutrients." said Zheng.

This work investigated the spatial and temporal variations of SOS over the past 20 years and the differences in the spring SOS changes among plant communities, which has great significance in understanding the change and adaptation of the tundra ecosystem under climate change. "The response of spring phenology to climatic and environmental change at different scale, as well as the impact of phenological change on carbon exchange in permafrost regions, require further exploration in our future works," said Xu.

Behind the simple headline "Additive manufacturing of silica aerogels" - the article was published on July 20th in the renowned scientific journal Nature - a groundbreaking development is hidden. Silica aerogels are light, porous foams that provide excellent thermal insulation. In practice, they are also known for their brittle behaviour, which is why they are usually reinforced with fibres or with organic or biopolymers for large-scale applications. Due to their brittle fracture behaviour, it is also not possible to saw or mill small pieces out of a larger aerogel block. Directly solidifying the gel in miniaturised moulds is also not reliably - which results in high scrap rates. This is why aerogels have hardly been usable for small-scale applications.

Stable, well-formed microstructures

The Empa team led by Shanyu Zhao, Gilberto Siqueira, Wim Malfait and Matthias Koebel have now succeeded in producing stable, well-shaped microstructures from silica aerogel by using a 3D printer. The printed structures can be as thin as a tenth of a millimeter. The thermal conductivity of the silica aerogel is just under 16 mW/(m*K) - only half that of polystyrene and even significantly less than that of a non-moving layer of air, 26 mW/(m*K). At the same time, the novel printed silica aerogel has even better mechanical properties and can even be drilled and milled. This opens up completely new possibilities for the post-processing of 3D printed aerogel mouldings.

With the method, for which a patent application has now been filed, it is possible to precisely adjust the flow and solidification properties of the silica ink from which the aerogel is later produced, so that both self-supporting structures and wafer-thin membranes can be printed. As an example of overhanging structures, the researchers printed leaves and blossoms of a lotus flower. The test object floats on the water surface due to the hydrophobic properties and low density of the silica aerogel - just like its natural model. The new technology also makes it possible for the first time to print complex 3D multi-material microstructures.

Insulation materials for microtechnology and medicine

With such structures it is now comparatively trivial to thermally insulate even the smallest electronic components from each other. The researchers were able to demonstrate the thermal shielding of a temperature-sensitive component and the thermal management of a local "hot spot" in an impressive way. Another possible application is the shielding of heat sources inside medical implants, which should not exceed a surface temperature of 37 degrees in order to protect body tissue.

A functional aerogel membrane

3D printing allows multilayer/multi-material combinations to be produced much more reliably and reproducibly. Novel aerogel fine structures become feasible and open up new technical solutions, as a second application example shows: Using a printed aerogel membrane, the researchers constructed a "thermos-molecular" gas pump. This permeation pump manages without any moving parts at all and is also known to the technical community as a Knudsen pump, named after the Danish physicist Martin Knudsen. The principle of operation is based on the restricted gas transport in a network of nanoscale pores or one-dimensional channels of which the walls are hot at one end and cold at the other. The team built such a pump from aerogel, which was doped on one side with black manganese oxide nanoparticles. When this pump is placed under a light source, it becomes warm on the dark side and starts to pump gases or solvent vapours.

Air purification without moving parts

These applications show the possibilities of 3D printing in an impressive way: 3D printing turns the high-performance material aerogel into a construction material for functional membranes that can be quickly modified to suit a wide range of applications. The Knudsen pump, which is driven solely by sunlight, can do more than just pump: If the air is contaminated with a pollutant or an environmental toxin such as the solvent toluene, the air can circulate through the membrane several times and the pollutant is chemically broken down by a reaction catalyzed by the manganese oxide nanoparticles. Such sun-powered, autocatalytic solutions are particularly appealing in the field of air analysis and purification on a very small scale because of their simplicity and durability.

Empa researchers are now looking for industrial partners who want to integrate 3D-printed aerogel structures into new high-tech applications.

Physicists from Trinity College Dublin have proposed a thermometer based on quantum entanglement that can accurately measure temperatures a billion times colder than those in outer space.

These ultra-cold temperatures arise in clouds of atoms, known as Fermi gases, which are created by scientists to study how matter behaves in extreme quantum states.

The work was led by the QuSys team at Trinity with postdoctoral fellows, Dr Mark Mitchison, Dr Giacomo Guarnieri and Professor John Goold, in collaboration with Professor Steve Campbell (UCD) and Dr Thomas Fogarty and Professor Thomas Busch working at OIST, Okinawa, Japan.

Their results have just been published (see here) as an Editor's Suggestion in the prestigious journal Physical Review Letters. A PDF copy of the article is also available on request.

Discussing the proposal, Professor Goold, head of Trinity's QuSys group, explains what an ultra-cold gas is. He said:

"The standard way in which a physicist thinks about a gas is to use a theory known as statistical mechanics. This theory was invented by giants of physics such as Maxwell and Boltzmann in the 19th century. These guys revived an old idea from the Greek philosophers that macroscopic phenomena, such as pressure and temperature, could be understood in terms of the microscopic motion of atoms. We need to remember that at the time, the idea that matter was made of atoms was revolutionary."

"At the dawn of the 20th century, another theory came to fruition. This is quantum mechanics and it may be the most important and accurate theory we have in physics. A famous prediction of quantum mechanics is that single atoms acquire wave-like features, which means that below a critical temperature they can combine with other atoms into a single macroscopic wave with exotic properties. This prediction led to a century-long experimental quest to reach the critical temperature. Success was finally achieved in the 90s with the creation of the first ultra-cold gases, cooled with lasers (Nobel Prize 1997) and trapped with strong magnetic fields - a feat which won the Nobel Prize in 2001."

"Ultra-cold gases like these are now routinely created in labs worldwide and they have many uses, ranging from testing fundamental physics theories to detecting gravitational waves. But their temperatures are mind-bogglingly low at nanokelvin and below! Just to give you an idea, one kelvin is -271.15 degrees Celsius. These gases are a billion times colder than that - the coldest places in the universe and they are created right here on Earth."

So what exactly is a Fermi gas?

"All particles in the universe, including atoms, come in one of two types called 'bosons' and 'fermions'. A Fermi gas comprises fermions, named after the physicist Enrico Fermi. At very low temperatures, bosons and fermions behave completely differently. While bosons like to clump together, fermions do the opposite. They are the ultimate social distancers! This property actually makes their temperature tricky to measure."

Dr Mark Mitchison, the first author of the paper, explains:

"Traditionally, the temperature of an ultra-cold gas is inferred from its density: at lower temperatures the atoms do not have enough energy to spread far apart, making the gas denser. But fermions always keep far apart, even at ultra-low temperatures, so at some point the density of a Fermi gas tells you nothing about temperature."

"Instead, we proposed using a different kind of atom as a probe. Let's say that you have an ultra-cold gas made of lithium atoms. You now take a different atom, say potassium, and dunk it into the gas. Collisions with the surrounding atoms change the state of your potassium probe and this allows you to infer temperature. Technically speaking, our proposal involves creating a quantum superposition: a weird state where the probe atom simultaneously does and doesn't interact with the gas. We showed that this superposition changes over time in a way that is very sensitive to temperature."

Dr Giacomo Guarnieri gives the following analogy:

"A thermometer is just a system whose physical properties change with temperature in a predictable way. For example, you can take the temperature of your body by measuring the expansion of mercury in a glass tube. Our thermometer works in an analogous way, but instead of mercury we measure the state of single atoms that are entangled (or correlated) with a quantum gas."

Professor Steve Campbell, UCD, remarks:

"This isn't just a far-flung idea -- what we are proposing here can actually be implemented using technology available in modern atomic physics labs. That such fundamental physics can be tested is really amazing. Among the various emerging quantum technologies, quantum sensors like our thermometer are likely to make the most immediate impact, so it is a timely work and it was highlighted by the editors of Physical Review Letters for that reason."

Professor Goold adds:

"In fact one of the reasons that this paper was highlighted was precisely because we performed calculations and numerical simulations with a particular focus on an experiment that was performed in Austria and published a few years ago in Science. Here the Fermi gas is a dilute gas of trapped Lithium atoms which were in contact with Potassium impurities. The experimentalists are able to control the quantum state with radio frequency pulses and measure out information on the gas. These are operations that are routinely used in other quantum technologies."

"The timescales that are accessible are simply amazing and would be unprecedented in traditional condensed matter physics experiments. We are excited that our idea to use these impurities as a quantum thermometer with exquisite precision could be implemented and tested with existing technology."

Atmospheric scientists have analyzed how the February near-total shutdown of mobility affected the air over China. Results show a striking drop in nitrogen oxides, a gas that comes mainly from tailpipes and is one component of smog.

Learning how behavior shifts due to the COVID-19 pandemic affect air quality is of immediate importance, since the virus attacks human lungs. The event is also a way for Earth scientists to study how the atmosphere responds to sudden changes in emissions.

"During the February 2020 shutdowns in China there was a large and rapid decline in nitrogen dioxide -- an air pollutant largely associated with transportation -- that is unprecedented in the satellite record," said Michael Diamond, a University of Washington doctoral student in atmospheric sciences.

"On the other hand, our analysis shows no dramatic changes in the total amount of aerosol particles in the atmosphere, or in cloud properties. This suggests the immediate climate-related impacts from the shutdown are negligible," Diamond said.

He is lead author of the study published Aug. 19 in Geophysical Research Letters.

While other studies have already looked at air quality during the pandemic, this is the first to take a more rigorous view, using all 15 years of satellite data. It uses a statistical method that compares what was seen in February 2020 to what would have been expected without the pandemic.

"Early in the quarantine period, there was some discussion that the Earth was healing itself, but some of those claims, like the dolphins in Venice, have turned out to be false," Diamond said. "The scientific community was interested in documenting what changes actually occurred."

The authors used data from NASA's Ozone Monitoring Instrument, or OMI, and Moderate Resolution Imaging Spectroradiometer, or MODIS, which have been monitoring the skies since 2005. These instruments use different wavelengths to monitor quantities like nitrogen oxides, airborne particulates and clouds.

In addition to using a longer record, the model accounted for the expected effects of China's environmental policies.

"China passed a clean air law in 2013, and ever since you can see that pollution is going down. So just for that reason, we might expect that the pollution in 2020 would be lower than in 2019," Diamond said.

The analysis also accounted for this past February's relatively hot and humid weather in China, which made gases more likely to react and form airborne particles.

"You still had some pretty bad smog events happening in the Beijing region, even during the lockdown," Diamond said.

The authors also considered the atmospheric effects of the Chinese New Year, which is celebrated in either late January or early February and generates both higher particulates from fireworks and lower traffic emissions from people being on holiday.

After accounting for all of these factors, the pandemic's effect on nitrogen oxides was a drop of 50% compared to what would be expected for February 2020, a drop unlike any other seen in the satellite observations.

"The difference we see is more than twice as large a drop as anything we saw in the record from 2005 to 2019, including from the 2008 Great Recession. In the statistics of atmospheric science, that's a giant signal. It is rare to see anything that striking," Diamond said.

While the change in nitrogen dioxide was dramatic, other quantities showed no significant change. Fine particulate matter, which has a bigger impact on human health and the climate, hardly changed over China during the shutdown. Passenger transportation virtually disappeared during the lockdown, but economic data show that heavy industry and energy production stayed fairly constant, Diamond said.

The fact that some quantities did not change is, for atmospheric scientists, a significant result in itself. Clouds, which are affected by pollution and have the biggest effect on climate, also showed no significant changes.

Co-author Rob Wood, a UW professor of atmospheric sciences, and Diamond collaborated on a recent publication that detected cloud changes due to pollution from ships. That study showed that many years of data were required to detect the effect on clouds.

"Our study suggests that since we found little change in particulate pollution due to COVID-19, we are unlikely to see any change in the clouds unless pollution changes over a longer time period due to a prolonged economic downturn," Wood said.

Overall, the findings agree with a recent study led by the UW showing that nitrogen dioxide dropped in several American cities during the peak quarantine period, but levels of other pollutants stayed fairly constant.

The response suggests that future clean air policies can't focus only on transportation emissions.

"When you're crafting these clean air strategies, you're probably not going to be able to attack just one sector; you'll have to address several sectors at once," Diamond said.