The study is the first to quantify the degree to which increases in PM2.5 pollution during the wildfires contributed to excess COVID-19 cases and deaths in the U.S. It was published online August 13, 2021, in Science Advances.

“The year 2020 brought unimaginable challenges in public health, with the convergence of the COVID-19 pandemic and wildfires across the western United States. In this study we are providing evidence that climate change — which increases the frequency and the intensity of wildfires — and the pandemic are a disastrous combination,” said Francesca Dominici, Clarence James Gamble Professor of Biostatistics, Population and Data Science at Harvard Chan School and senior author of the study.

In 2020, at the same time the nation was contending with the COVID-19 pandemic, huge wildfires swept across the western U.S., including some of the largest ever in California and Washington. Wildfires produce high levels of fine particulate matter (PM2.5), which has been linked with a host of negative health outcomes, including premature death, asthma, chronic obstructive pulmonary diseases (COPD), and other respiratory illnesses. In addition, recent studies have found a link between short- and long-term exposure to PM2.5 and COVID-19 cases and deaths.

The researchers — from Harvard Chan School, the John A. Paulson School of Engineering and Applied Sciences at Harvard University, and the Environmental Systems Research Institute in Redlands, Calif. — built and validated a statistical model to quantify the extent to which wildfire smoke may have contributed to excess COVID-19 cases and deaths in California, Oregon, and Washington, three states that bore the brunt of the 2020 wildfires. They looked at the connection between county- and daily-level data on PM2.5 air concentrations from monitoring data, wildfire days from satellite data, and the number of COVID-19 cases and deaths in 92 counties, which represented 95% of the population across the three states. The researchers accounted for factors such as weather, population size, and societal patterns of social distancing and mass gatherings.

The study found that from August 15 to October 15, 2020, when fire activity was greatest, daily levels of PM2.5 during wildfire days were significantly higher than on non-wildfire days, with a median of 31.2 micrograms per cubic meter of air (µg/m3) versus 6.4 (µg/m3). In some counties, the levels of PM2.5 on wildfire days reached extremely high levels. For instance, from September 14 to September 17, 2020, Mono County, Calif., experienced four days in a row with PM2.5 levels higher than 500 µg/m3 as a result of the Creek Fire. Such levels are deemed “hazardous” by the U.S. Environmental Protection Agency.

Wildfires amplified the effect of exposure to PM2.5 on COVID-19 cases and deaths, up to four weeks after the exposure, the study found. In some counties, the percentage of the total number of COVID-19 cases and deaths attributable to high PM2.5 levels was substantial.

On average across all counties, the study found that a daily increase of 10 µg/m3 in PM2.5 each day for 28 subsequent days was associated with an 11.7% increase in COVID-19 cases, and an 8.4% increase in COVID-19 deaths. The biggest effects for the COVID-19 cases were in the counties of Sonoma, Calif., and Whitman, Wash., with a 65.3% and 71.6% increase, respectively. The biggest effects for the COVID-19 deaths were in Calaveras, Calif., and San Bernardino, Calif., with a 52.8% and 65.9% increase, respectively.

When the researchers looked at individual wildfire days and at individual counties, they found that Butte, Calif. and Whitman, Wash. had the highest percentages of total COVID-19 cases attributable to high levels of PM2.5 during the wildfires: Among the total number of COVID-19 cases that occurred in these counties, 17.3% and 18.2%, respectively, were attributable to high levels of PM2.5. Butte, Calif. and Calaveras, Calif. had the highest percentages of total COVID-19 deaths attributable to high levels of PM2.5 during the wildfires: Among the total number of COVID-19 deaths that occurred in these counties, 41% and 137.4%, respectively, were directly attributable to high levels of PM2.5.

Across the three states studied, the cumulative number of COVID-19 cases and deaths attributable to daily increases in PM2.5 from wildfires was, respectively, 19,700 and 750, the study found.

“Climate change will likely bring warmer and drier conditions to the West, providing more fuel for fires to consume and further enhancing fire activity. This study provides policymakers with key information regarding how the effects of one global crisis — climate change — can have cascading effects on concurrent global crises — in this case, the COVID-19 pandemic,” said Dominici.

Co-first authors of the study were Xiaodan Zhou of the Environmental Systems Research Institute and Kevin Josey from the Department of Biostatistics at Harvard Chan School. Leila Kamareddine of the Department of Biostatistics at Harvard Chan School also contributed, as did Miah C. Caine and Loretta J. Mickley from Harvard’s John A. Paulson School of Engineering and Applied Sciences, and Tianjia Liu from Harvard’s Department of Earth and Planetary Sciences.

Funding for the study came from the Environmental Protection Agency (grant 83587201-0), the National Institutes of Health (grants R01ES026217, R01MD012769, R01ES028033, 1R01AG060232-01A1, 1R01ES030616, 1R01AG066793-01R01, 1R01ES029950, and 5T32ES007142), the Alfred P. Sloan Foundation, and the Vice Provost for Research-Harvard University.

Now, researchers have uncovered hidden potential in these metasurfaces and, in a new paper, demonstrated optical devices that manipulate light’s polarization state with an unprecedented degree of control.

“This research shows that the ability to switch between holographic images that need not be limited to just two polarization states,” said Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS and senior author of the paper. “Our new metasurface can encode an unlimited number of holographic images or manipulate light in virtually infinite number of directions based on a very large number of polarization states.”

The research, published in Science Advances, demonstrates a new way to control polarized light with metasurfaces. This new approach — in which the researchers can engineer a holographic image with a polarization-tunable response across the image itself — could lead to applications in diverse fields including imaging, microscopes, displays, and even astronomy.

“This advancement is general and could be applied to almost any kind of optical system that uses polarized light,” said Noah Rubin, a postdoctoral fellow at SEAS and first author of the paper. “Specifically, this suggests that metasurfaces could be used in new types of laser systems whose output light could be engineered based on light’s polarization state, or perhaps even in telescope systems where similar types of optics are already being used to aid in the detection of Earth-like exoplanets.”

“Holography has always been a popular technique to record and display information,” said Aun Zaidi, a graduate student at SEAS and co-lead author of the paper. “We have taken a fundamental principle of holography and generalized it in a way that greatly expands the information capacity of this rather old technique.”

Next, the researchers aim to understand these devices better, including how they could be used in real-world applications.

The Harvard Office of Technology Development has protected the intellectual property relating to this project and is exploring commercialization opportunities.

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Materials provided by Harvard John A. Paulson School of Engineering and Applied Sciences. Original written by Leah Burrows. Note: Content may be edited for style and length.

Many positive-strand RNA viruses share a strategy to avoid detection by a cell’s immune system until they can increase their numbers. Among them are the SARS-CoV-2 virus, flaviviruses such as West Nile and Zika, as well as the picornaviruses behind polio and some heart and brain inflammation.

After invading a cell, these types of viruses take over part of an intracellular membrane, within the system of membranes that form compartments within the cell. The viruses use this modified organelle as a refuge for replicating themselves. Their viral products are thereby shielded from most of the cell’s innate immune sensors.

A new study looks at how a variant of the enzyme, oligoadenylate synthetase 1, targets the hiding spots of these viruses. This isoform of the enzyme is called OAS1 p46. The OAS family of sensors are prompted by interferon to seek out RNA viruses or their locations. This reconnaissance helps the cell defend against the attack.

Although much research has documented the importance of OAS proteins in activating an enzyme that cleaves viral RNA in order to block a variety of different viruses from replicating, little is known about how individual OAS proteins contribute to this breadth of antiviral activity.

Most of a cell’s RNA virus sensors are deployed to detect viruses within the cytosol that is between the nucleus and the outer membrane of the cell. They sense viral RNA that accumulates in the cytosol during infection.

In contrast, the OAS1 p46 protein isoform homes in on the endomembrane system, particularly the endoplasmic reticulum and the Golgi apparatus. The Golgi is a cellular mailing room where proteins are packaged and dispatched.

The OAS1 p46 isoform is also prenylated, a biochemical tune up that, in this case, gives this protein the ability to traffic to the membranes. This isoform also has additional help from amino acids at the tail end of the protein that also improves its antiviral activity.

“Targeting innate RNA sensors to the endomembrane system may enhance their ability to sense RNA generated by viruses that use these compartments for replication,” the researchers noted in their paper, which appears in eLife.

The senior author of the paper is Ram Savan, an associate professor of immunology at the University of Washington School of Medicine in Seattle. His lab explores how variations in, and regulation of, innate immunity genes help determine resistance or susceptibility to serious viral infections that affects us.

The lead authors on the international, multi-institutional study are Frank W. Soveg, a recent graduate student in the Ram Savan Lab and Johannes Schwerk, acting instructor in immunology at the UW School of Medicine. All three are also members of the UW Center for Innate Immunity and Immune Disease.

The authors found that the OAS1 p46 isoform’s localization to these membranes enhances the cell’s virus sensors access the viral replication sites. This in turn results in a stronger antiviral activity against the sorts of RNA viruses that tend to use this hiding-in-a-membrane tactic to covertly multiply.

“Our virological analysis,” Ram Savan observed, “shows that OAS1 p46 isoform is pan-antiviral against multiple positive-strand RNA viruses including flavivirus, picornavirus and SARS-CoV-2.”

The scientists went on to analyze the human genetics behind the OAS1 p46 isoform, and the benefits of having this genetic variant, by examining lab samples from patients affected by COVID-19.

“In this study,” Ram Savan noted, “we identify a causal single nucleotide variant in the oligoadenylate synthetase 1 gene that predicts COVID-19 severity.”

Savan explained that the genetic data show a strong association of the A allele that produces the OAS1 p42 protein isoform with severe COVID-19 disease requiring mechanical ventilation of patients. On the other hand, the G allele producing OAS1p46 protein protects from severe COVID-19. The results from patients in the Pacific Northwest were reproduced in a larger European cohort.

In summary, the scientists noted that their findings show that targeting endomembranes is vital for the antiviral action of OAS1 against specific types of immunity-evading pathogens. The work demonstrates how critical such intracellular membrane targeting is in detecting dangerous viruses that replicate on these membranes. The results also suggest that the control of SARS-CoV-2 replication early on in infection, through the actions of the OAS1-p46 isoform, is an important factor in reducing the severity of COVID-19 disease.

This project was funded by National Institutes of Health (grants AI145974, AI108765, AI135437, AI104002, AI118916, AI145296, AI127463, AI100625, AI106677, GM007270, and AI140530; T32 HL007312); Postdoctoral Research Fellowship from the German Research Foundation and support from the Cancer Research Institute Irvington Fellowship Program.

“In this case, first place is the worst place to be,” said NOAA Administrator Rick Spinrad, Ph.D. “July is typically the world’s warmest month of the year, but July 2021 outdid itself as the hottest July and month ever recorded. This new record adds to the disturbing and disruptive path that climate change has set for the globe.”

July 2021 by the numbers

• Around the globe: the combined land and ocean-surface temperature was 1.67 degrees F (0.93 of a degree C) above the 20th-century average of 60.4 degrees F (15.8 degrees C), making it the hottest July since records began 142 years ago. It was 0.02 of a degree F (0.01 of a degree C) higher than the previous record set in July 2016, which was then tied in 2019 and 2020.
• The Northern Hemisphere: the land-surface only temperature was the highest ever recorded for July, at an unprecedented 2.77 degrees F (1.54 degrees C) above average, surpassing the previous record set in 2012.
• Regional records: Asia had its hottest July on record, besting the previous record set in 2010; Europe had its second-hottest July on record — tying with July 2010 and trailing behind July 2018; and North America, South America, Africa and Oceania all had a top-10 warmest July.

Extreme heat and global climate change

With last month’s data, it remains very likely that 2021 will rank among the world’s 10-warmest years on record, according to NCEI’s Global Annual Temperature Rankings Outlook.

Extreme heat detailed in NOAA’s monthly NCEI reports is also a reflection of the long-term changes outlined in a major report released this week by the Intergovernmental Panel on Climate Change.

“Scientists from across the globe delivered the most up-to-date assessment of the ways in which the climate is changing,” Spinrad said in a statement. “It is a sobering IPCC report that finds that human influence is, unequivocally, causing climate change, and it confirms the impacts are widespread and rapidly intensifying.”

Other notable highlights from NOAA’s July global climate report

• Sea ice coverage varied by hemisphere: The Arctic sea ice coverage (extent) for July 2021 was the fourth-smallest for July in the 43-year record, according to analysis by the National Snow and Ice Data Center. Only July 2012, 2019 and 2020 had a smaller sea ice extent. Antarctic sea ice extent was above average in July — the largest July sea ice extent since 2015 and the eighth highest on record.

• The tropics were busier than average: In the Atlantic basin, the season’s earliest fifth-named storm, Elsa, formed on July 1. The Eastern North and Western Pacific basins each logged three named storms. Overall, global tropical cyclone activity this year so far (through July) has been above-normal for the number of named storms.

More information

See NOAA’s July global climate report and images from the NCEI website: https://www.ncei.noaa.gov/news/global-climate-202107

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Materials provided by NOAA. Note: Content may be edited for style and length.

The study by researchers at North Carolina State University examined the interactions of warmer temperatures, crop yield risk and crop insurance participation by farmers. For the study, researchers developed models using historical county-level corn and soybean production data in the United States, with an eye toward understanding the production impacts of rising temperatures.

The researchers found that variation in crop yields due to higher temperatures rose when more farmers had crop insurance. Interestingly, the results showed greater variability effects for corn yields than for soybean yields.

“This could be an unintended consequence of providing subsidies for crop insurance,” said Rod M. Rejesus, professor of agricultural and resource economics at NC State and the corresponding author of the research study. “The concept of moral hazard could be present here. If insurance will cover crop losses due to various effects like drought or severe weather, a farmer may not want to pay the extra expense for climate change adaptation efforts such as using cover crops to improve soil health, for example.”

Climate change — including warmer temperatures — increases the variability of crop yields; farming becomes a riskier proposition as this variability rises.

The study models indicate that an increase of daily minimum and maximum temperatures of 1 degree Celsius would increase county-level corn yield variability by 8.6 bushels per acre if 80% of farmers in a county have crop insurance. The same temperature rise in a county with 10% crop insurance participation would increase corn yield variability by just 6.2 bushels per acre.

The researchers pose possible solutions to this quandary for policymakers. They include providing more subsidies to encourage farmers’ use of climate change mitigation efforts — like soil health practices — and starting high-level policy conversations about how to possibly tweak rules and guidelines that govern crop insurance contracts in order to reduce the disincentive effects.

Rejesus will continue to study the effects of climate change, crop yields and crop insurance, including the role of certain climate mitigation efforts by farmers.

The paper appears in the European Review of Agricultural Economics. Former NC State Ph.D. student Ruixue Wang is the paper’s first author. NC State postdoctoral researcher Serkan Aglassan also co-authored paper. Support for the work was provided in part by the U.S. Department of Agriculture’s NIFA Hatch Project No. NC02696.

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Materials provided by North Carolina State University. Original written by Mick Kulikowski. Note: Content may be edited for style and length.

Until now, quantum computer engineers and scientists have worked with a proof-of-concept model of quantum processors by demonstrating the control of only a handful of qubits.

But with their latest research, published today in Science Advances, the team have found what they consider ‘the missing jigsaw piece’ in the quantum computer architecture that should enable the control of the millions of qubits needed for extraordinarily complex calculations.

Dr Jarryd Pla, a faculty member in UNSW’s School of Electrical Engineering and Telecommunications says his research team wanted to crack the problem that had stumped quantum computer scientists for decades: how to control not just a few, but millions of qubits without taking up valuable space with more wiring, using more electricity, and generating more heat.

“Up until this point, controlling electron spin qubits relied on us delivering microwave magnetic fields by putting a current through a wire right beside the qubit,” Dr Pla says.

“This poses some real challenges if we want to scale up to the millions of qubits that a quantum computer will need to solve globally significant problems, such as the design of new vaccines.

“First off, the magnetic fields drop off really quickly with distance, so we can only control those qubits closest to the wire. That means we would need to add more and more wires as we brought in more and more qubits, which would take up a lot of real estate on the chip.”

And since the chip must operate at freezing cold temperatures, below -270°C, Dr Pla says introducing more wires would generate way too much heat in the chip, interfering with the reliability of the qubits.

“So we come back to only being able to control a few qubits with this wire technique,” Dr Pla says.

Lightbulb moment

The solution to this problem involved a complete reimagining of the silicon chip structure.

Rather than having thousands of control wires on the same thumbnail-sized silicon chip that also needs to contain millions of qubits, the team looked at the feasibility of generating a magnetic field from above the chip that could manipulate all of the qubits simultaneously.

This idea of controlling all qubits simultaneously was first posited by quantum computing scientists back in the 1990s, but so far, nobody had worked out a practical way to do this — until now.

“First we removed the wire next to the qubits and then came up with a novel way to deliver microwave-frequency magnetic control fields across the entire system. So in principle, we could deliver control fields to up to four million qubits,” says Dr Pla.

Dr Pla and the team introduced a new component directly above the silicon chip — a crystal prism called a dielectric resonator. When microwaves are directed into the resonator, it focuses the wavelength of the microwaves down to a much smaller size.

“The dielectric resonator shrinks the wavelength down below one millimetre, so we now have a very efficient conversion of microwave power into the magnetic field that controls the spins of all the qubits.

“There are two key innovations here. The first is that we don’t have to put in a lot of power to get a strong driving field for the qubits, which crucially means we don’t generate much heat. The second is that the field is very uniform across the chip, so that millions of qubits all experience the same level of control.”

Quantum team-up

Although Dr Pla and his team had developed the prototype resonator technology, they didn’t have the silicon qubits to test it on. So he spoke with his engineering colleague at UNSW, Scientia Professor Andrew Dzurak, whose team had over the past decade demonstrated the first and the most accurate quantum logic using the same silicon manufacturing technology used to make conventional computer chips.

“I was completely blown away when Jarryd came to me with his new idea,” Prof. Dzurak says, “and we immediately got down to work to see how we could integrate it with the qubit chips that my team has developed.

“We put two of our best PhD students on the project, Ensar Vahapoglu from my team, and James Slack-Smith from Jarryd’s.

“We were overjoyed when the experiment proved successful. This problem of how to control millions of qubits had been worrying me for a long time, since it was a major roadblock to building a full-scale quantum computer.”

Once only dreamt about in the 1980s, quantum computers using thousands of qubits to solve problems of commercial significance may now be less than a decade away. Beyond that, they are expected to bring new firepower to solving global challenges and developing new technologies because of their ability to model extraordinarily complex systems.

Climate change, drug and vaccine design, code decryption and artificial intelligence all stand to benefit from quantum computing technology.

Looking ahead

Next up, the team plans to use this new technology to simplify the design of near-term silicon quantum processors.

“Removing the on-chip control wire frees up space for additional qubits and all of the other electronics required to build a quantum processor. It makes the task of going to the next step of producing devices with some tens of qubits much simpler,” says Prof. Dzurak.

“While there are engineering challenges to resolve before processors with a million qubits can be made, we are excited by the fact that we now have a way to control them,” says Dr Pla.