The numbers don't lie: Australia is failing at maths and we need to find a new formula to arrest the decline
May 17, 2022
Divide, subtract, add, multiply: whatever way you cut it, Australia is heading in one direction when it comes to global maths rankings -- downwards. From an OECD mathematics ranking of 11 in the world 20 years ago, Australian secondary students are now languishing in 29th place out of 38 countries, according to the most recent statistics.
The sliding maths rankings have created widespread debate over whether curriculum changes are needed in our schools, but a new international paper co-authored by University of South Australia cognitive psychologist Dr Fernando Marmolejo-Ramos could provide part of the solution.In the latest edition of Integrative Psychology and Behavioural Science, Dr Marmolejo-Ramos and researchers from China and Iran explain why simple gestures such as hand motions are important in helping students understand mathematical concepts.
"Many people struggle with mathematics and there is a lot of anxiety around it because it is an abstract topic," Dr Marmolejo-Ramos says. "You see the numbers, equations and graphs, but unless you engage human motor and sensory skills, they can be very difficult to grasp."
To get maths concepts across, it is important to bring together language, speech intonation, facial expressions and hand gestures, particularly the latter, the researchers say.
"Using your hands to create triangular, spherical, circular shapes and straight lines, reflecting the formulas you are trying to explain, is vital. It helps our brain better understand the concepts and commit them to memory."
Gestures are body movements that are learnt from infancy, usually before speech, so they are ingrained in humans as a way of processing and acquiring new knowledge.
Dr Marmolejo-Ramos says hand gestures are more relevant in teaching mathematics than other subjects because they engage our sensorimotor skills to help students interpret numbers more effectively.
The shift from face-to-face teaching towards online learning in the past two years due to the COVID-19 pandemic has made it even more challenging for maths students, Dr Marmolejo-Ramos says.
"When the only input you have is from a screen and a set of headphones, it is more difficult to use tools and gestures on screen. It's not impossible, however, and if online learning is going to become more widespread, then hand gestures should be incorporated into the online teaching."
"People struggle with mathematics for several reasons. It's progressively demanding but if you grasp the basics, the curve is not as steep."
"Gestures Enhance Executive Functions for the Understanding of Mathematical Concepts" is published in the Integrative Psychological and Behavioural Science journal. It is authored by Omid Khatin-Zadeh from the University of Electronic Science and Technology, China; Dr Zahra Eskandari from the Chabahar Maritime University, Iran; and Dr Fernando Marmolejo-Ramos from the University of South Australia.
The OECD's Programme for International Student Assessment (PISA) assesses 15-year-olds' maths, science and reading skills every three years. The most recent assessment in 2019 show that Australia's performance in maths has been declining since 2003.
On average, Australian maths students are 14 months behind than where they were 20 years ago, with 46 per cent of 15-year-olds failing to meet the national standard of proficiency in mathematics.
Omid Khatin-Zadeh, Zahra Eskandari, Fernando Marmolejo-Ramos. Gestures Enhance Executive Functions for the Understating of Mathematical Concepts. Integrative Psychological and Behavioral Science, 2022; DOI: 10.1007/s12124-022-09694-4
Desktop air curtain system prevents spread of COVID-19 in hospital settings
May 17, 2022
In efforts to prevent the spread of COVID-19, miniaturizing air curtains for hospital wards, labs, and other health care settings is gaining traction as a viable solution to inadequate face masks or when social distancing is not a realistic option.
In AIP Advances, published by AIP Publishing, researchers in Japan developed a desktop air curtain system (DACS) that blocks all incoming aerosol particles.
"We envisage this system will be effective as an indirect barrier for use in blood-testing labs, hospital wards, and other situations where sufficient physical distance cannot be maintained, such as at a reception counter," co-author Kotaro Takamure said.
An air curtain, or air door, is a fan-powered ventilation system that creates an air seal over an entryway. Hospitals use them to prevent ambulance fumes and other contaminants from reaching the inside of an emergency room.
One challenge in developing smaller air curtains is fully blocking emitted aerosol particles over time because it is difficult to maintain the air wall over a long distance. As a result, the devices gradually lose air-discharge intensity, creating a turbulent flow that allows infected aerosol particles to escape into the surrounding environment.
The DACS contains a discharge and suction port to help address this problem. A generator at the top of the DACS produces the airflow, which is guided to the suction port at the bottom of the device. This prevents airflow dispersion, thus leading to the collection of all the aerosol particles at the suction port. A high-efficiency particulate air (HEPA) filter can be installed inside the suction port for air purification.
The researchers are developing an accompanying virus inactivation system equipped with ultraviolet light that connects to the suction port. After the air is sanitized with the UV light, it is recirculated to maintain airflow of the air curtain and air pressure in the room.
The researchers tested their device by using an air compressor connected to a mannequin to simulate breathing. Dioctyl sebacate, a widely used solvent that spreads easily, was added to the airflow to create aerosol particles. Particle image velocimetry and high-speed cameras were used to determine the DACS's blocking effect.
The aerosol particles approaching the DACS abruptly bent toward the suction port, signifying that air curtain flow fully blocked all incoming aerosol particles.
When the researchers placed the mannequin's arm through the DACS to imitate a blood-collection scenario, they found the airflow above the arm was disrupted. However, the aerosol blocking performance remained unaffected.
The DACS was tested on patients during blood collection at Nagoya University Hospital. The researchers are looking at lowering the suction port, so the arm can be placed below the heart for proper blood collection.
DACS tested on patient at Nagoya University Hospital CREDIT: Junki Mikami (FUIGO)
Kotaro Takamure, Yasuaki Sakamoto, Tetsuya Yagi, Yasumasa Iwatani, Hiroshi Amano, Tomomi Uchiyama. Blocking effect of desktop air curtain on aerosols in exhaled breath. AIP Advances, 2022; 12 (5): 055323 DOI: 10.1063/5.0086659
Early Earth: Tungsten isotopes in seawater provide insights into the co-evolution of Earth's mantle and continents
May 17, 2022
In a study published in the journal Nature Communications, Andrea Mundl-Petermeier and Sebastian Viehmann of the Department of Lithospheric Research at the University of Vienna have demonstrated that a new geochemical archive -- 182Tungsten in banded iron formations -- can be used to simultaneously trace both the evolution of the Earth's mantle and continents throughout Earth's history. This offers new opportunities to better understand the Precambrian Earth in the future.In order to investigate how the Earth's mantle developed in the early Earth period, the short-lived 182Hafnium-182Tungsten isotope system has been in the focus before: 182Tungsten indicates, among other things, how much the Earth was exposed to intense meteorite impacts towards the end of its formation and how quickly Earth's mantle mixed and homogenized with these meteoritic components throughout Earth's history.
However, until now, magmatic rocks from different, but very limited relicts of ancient continents -- for example, Australia or South Africa -- had to be studied for these isotopes. Andrea Mundl-Petermeier and Sebastian Viehmann from the Department of Lithospheric Research at the University of Vienna and colleagues at the University of Cologne and Jacobs University Bremen, now discovered a new geochemical archive published it in the journal Nature Communications: tungsten isotope signatures in banded iron formations (BIFs), which predominantly formed in the Precambrian, i.e., between 3.8 billion and about 540 million years ago.
Evolution of the Earth's mantle and the continents
Using the 2.7 billion-year-old iron formation from the Temagami greenstone belt in Canada, the team was able to reconstruct that iron- and silica-rich layers deposited from seawater can simultaneously record the evolution of the Earth's mantle and crust. With state-of-the-art instruments from the GeoCosmoChronology group and the new Geoscience Solid State Mass Spectrometry (GeoIsotopes) Core Facility at the Department of Lithospheric Research, the research team obtained high-precision isotope measurements of individual bright quartz and dark iron layers.
"With the help of high-precision measurement methods, we were able to resolve small but distinct differences in 182W of individual layers," says Andrea Mundl-Petermeier from the Department of Lithospheric Research.
The new approach now tackles the long-standing questions regarding mantle and crust evolution from a seawater perspective: banded iron ores are formed by chemical deposition from the ocean.
"The BIFs studied from the Temagami area thus directly represent seawater chemistry 2.7 billion years ago," explains geologist Sebastian Viehmann: "We are looking at the Earth at that time from the perspective of the ocean."
Using the 2.7 billion-year-old iron formation from the Temagami greenstone belt in Canada, the team was able to reconstruct that both iron- and silica-rich layers of the BIF deposited from seawater provide information on the evolution of the Earth's mantle and crust, respectively. © Sebastian Viehmann
A. Mundl-Petermeier, S. Viehmann, J. Tusch, M. Bau, F. Kurzweil, C. Münker. Earth’s geodynamic evolution constrained by 182W in Archean seawater. Nature Communications, 2022; 13 (1) DOI: 10.1038/s41467-022-30423-3
In text Image (top): In a study published in the journal Nature Communications, Andrea Mundl-Petermeier and Sebastian Viehmann from the Department of Lithospheric Research have demonstrated that a new geochemical archive - 182Tungsten in banded iron formations - can be used to simultaneously trace both the evolution of the Earth's mantle and continents through Earth’s history. © David Diekrup 2011
What we're still learning about how trees grow
May 13, 2022
What will happen to the world's forests in a warming world? Will increased atmospheric carbon dioxide help trees grow? Or will extremes in temperature and precipitation hold growth back? That all depends on whether tree growth is more limited by the amount of photosynthesis or by the environmental conditions that affect tree cell growth -- a fundamental question in tree biology, and one for which the answer wasn't well understood, until now.
A study led by University of Utah researchers, with an international team of collaborators, finds that tree growth does not seem to be generally limited by photosynthesis but rather by cell growth. This suggests that we need to rethink the way we forecast forest growth in a changing climate, and that forests in the future may not be able to absorb as much carbon from the atmosphere as we thought.
"A tree growing is like a horse and cart system moving forward down the road," says William Anderegg, an associate professor in the U's School of Biological Sciences and principal investigator of the study. "But we basically don't know if photosynthesis is the horse most often or if it's cell expansion and division. This has been a longstanding and difficult question in the field. And it matters immensely for understanding how trees will respond to climate change."
The study is published in Science and is funded by the U.S. Department of Agriculture, the David and Lucille Packard Foundation, the National Science Foundation, the U.S. Department of Energy and the Arctic Challenge for Sustainability II.
Source vs. sink
We learned the basics in elementary school -- trees produce their own food through photosynthesis, taking sunlight, carbon dioxide and water and turning it into leaves and wood.
There's more to the story, though. To convert carbon gained from photosynthesis into wood requires wood cells to expand and divide.
So trees get carbon from the atmosphere through photosynthesis. This is the trees' carbon source. They then spend that carbon to build new wood cells -- the tree's carbon sink.
If the trees' growth is source-limited, then it's limited only by how much photosynthesis the tree can carry out and tree growth would be relatively easy to predict in a mathematical model. So rising carbon dioxide in the atmosphere should ease that limitation and let trees grow more, right?
But if instead the trees' growth is sink-limited, then the tree can only grow as fast as its cells can divide. Lots of factors can directly affect both photosynthesis and cell growth rate, including temperature and the availability of water or nutrients. So if trees are sink-limited, simulating their growth has to include the sink response to these factors.
The researchers tested that question by comparing the trees' source and sink rates at sites in North America, Europe, Japan and Australia. Measuring carbon sink rates was relatively easy -- the researchers just collected samples from trees that contained records of growth. "Extracting wood cores from tree stems and measuring the width of each ring on these cores essentially lets us reconstruct past tree growth," says Antoine Cabon, a postdoctoral scholar in the School of Biological Sciences and lead author of the study.
Measuring carbon sources is tougher, but doable. Source data was measured with 78 eddy covariance towers, 30 feet tall or more, that measure carbon dioxide concentrations and wind speeds in three dimensions at the top of forest canopies, Cabon says. "Based on these measurements and some other calculations," he says, "we can estimate the total forest photosynthesis of a forest stand."
Wood cores prepared for measuring ring width. PHOTO CREDIT: Antoine Cabon
Decoupled
The researchers analysed the data they collected, looking for evidence that tree growth and photosynthesis were processes that are linked, or coupled. They didn't find it. When photosynthesis increased or decreased, there was not a parallel increase or decrease in tree growth.
"Strong coupling between photosynthesis and tree growth would be expected in the case where tree growth is source limited," Cabon says. "The fact that we mostly observe a decoupling is our principal argument to conclude that tree growth is not source-limited."
Surprisingly, the decoupling was seen in environments across the globe. Cabon says they did expect to see some decoupling in some places, but "we did not expect to see such a widespread pattern."
The strength of coupling or decoupling between two processes can lie on a spectrum, so the researchers were interested in what conditions led to stronger or weaker decoupling. Fruit-bearing and flowering trees, for example, exhibited different source-sink relationships than conifers. More diversity in a forest increased coupling. Dense, covered leaf canopies decreased it.
Finally, coupling between photosynthesis and growth increased in warm and wet conditions, with the opposite also true: that in cold and dry conditions, trees are more limited by cell growth.
Cabon says that this last finding suggests that the source vs. sink issue depends on the tree's environment and climate. "This means that climate change may reshape the distribution of source and sink limitations of the world forests," he says.
A new way to look forward
The key takeaway is that vegetation models, which use mathematical equations and plant characteristics to estimate future forest growth, may need to be updated. "Virtually all these models assume that tree growth is source limited," Cabon says.
For example, he says, current vegetation models predict that forests will thrive with higher atmospheric carbon dioxide. "The fact that tree growth is often sink limited means that for many forests this may not actually happen."
That has additional implications: forests currently absorb and store about a quarter of our current carbon dioxide emissions. If forest growth slows down, so do forests' ability to take in carbon, and their ability to slow climate change.
Other authors of the study include Steven A. Kannenberg, University of Utah; Altaf Arain and Shawn McKenzie, McMaster University; Flurin Babst, Soumaya Belmecheri and David J. Moore, University of Arizona; Dennis Baldocchi, University of California, Berkeley; Nicolas Delpierre, Université Paris-Saclay; Rossella Guerrieri, University of Bologna; Justin T. Maxwell, Indiana University Bloomington; Frederick C. Meinzer and David Woodruff, USDA Forest Service, Pacific Northwest Research Station; Christoforos Pappas, Université du Québec à Montréal; Adrian V. Rocha, University of Notre Dame; Paul Szejner, National Autonomous University of Mexico; Masahito Ueyama, Osaka Prefecture University; Danielle Ulrich, Montana State University; Caroline Vincke, Universit. Catholique de Louvain; Steven L. Voelker, Michigan Technological University and Jingshu Wei, Polish Academy of Sciences.
Antoine Cabon, Steven A. Kannenberg, Altaf Arain, Flurin Babst, Dennis Baldocchi, Soumaya Belmecheri, Nicolas Delpierre, Rossella Guerrieri, Justin T. Maxwell, Shawn McKenzie, Frederick C. Meinzer, David J. P. Moore, Christoforos Pappas, Adrian V. Rocha, Paul Szejner, Masahito Ueyama, Danielle Ulrich, Caroline Vincke, Steven L. Voelker, Jingshu Wei, David Woodruff, William R. L. Anderegg. Cross-biome synthesis of source versus sink limits to tree growth. Science, 2022; 376 (6594): 758 DOI: 10.1126/science.abm4875
New university of south australia micro device injects a boost to IVF success
May 16, 2022
A research team led by the University of Adelaide, in partnership with medical technology company Fertilis, has delivered a ground-breaking new micro-device to streamline the only fertility treatment procedure available for men with low sperm counts.
The first-of-its-kind device will allow more IVF clinics to offer Intracytoplasmic Sperm Injection (ICSI) as a treatment, while several IVF procedures, such as embryo culture, embryo cryopreservation and in vitro maturation, will also be improved by using the device.
Intracytoplasmic Sperm Injection (ICSI) device. Image: UniSA
ICSI is a slow and difficult procedure which involves the injection of a single sperm into an egg for fertilisation, and it can only be carried out by experienced embryologists.
This new technology -- smaller than a pinhead in size -- holds up to 10 eggs in segregated positions for quicker injection, making it easier for embryologists to track and avoid the risk of errors.
Lead researcher Dr Kylie Dunning, from the University of Adelaide's Robinson Research Institute, said the device will cut treatment time in half, require less training for embryologists with less expensive equipment than current ICSI treatment and improve access to the procedure for more patients.
"The development of this new, innovative approach is an important breakthrough for people wanting to start a family who haven't been able to due to male infertility," Dr Dunning said.
"By removing the need for the pipette that normally holds the unfertilised egg in position during ICSI, this device simplifies the injection process, reduces dependency on a high level of technical experience and will dramatically improve embryo production.
"This discovery removes significant barriers to treatment for people with infertility and will improve IVF success."
Dr Kylie Dunning. Photo: UniSA
Device inventor and Fertilis co-founder, Professor Jeremy Thompson, said his company is excited to bring the breakthrough device to market.
"Where IVF science has excelled, technology has tended to stagnate -- until now," Professor Thompson said.
"ICSI hasn't changed since its discovery 30 years ago. Continued innovation in the IVF lab like this is the only way we will boost success and reduce the financial and emotional burden for patients."
The device will undergo global clinical trials in 2022.
This cutting-edge development would not have been possible without the support of the Australian Research Council and The Hospital Research Foundation Group.
Paul Flynn, Chief Executive Officer of the Hospital Research Foundation Group, said the organisation has been proud to support Dr Dunning's research during the past three years to improve IVF success rates.
"This device is set to be a game changer for thousands of hopeful parents who need to rely on ICSI," Mr Flynn said.
Primary author, Suliman Yagoub, is a PhD candidate in the School of Biomedicine at The University of Adelaide.
Suliman H. Yagoub, Jeremy G. Thompson, Antony Orth, Kishan Dholakia, Brant C. Gibson, Kylie R. Dunning. Fabrication on the microscale: a two-photon polymerized device for oocyte microinjection. Journal of Assisted Reproduction and Genetics, 2022; DOI: 10.1007/s10815-022-02485-1
Validation brings new predictive capability to global megafire smoke impacts
May 17, 2022
Satellite- and ground-based observations of Australia and British Columbia blazes help increase resolution of models.
New research modelling smoke from two recent megafires sets the stage for better forecasting of how emissions from these global-scale events will behave and impact temperatures. As huge wildfires become more common under climate change, increased attention has focused on the intensity and duration of their emissions, which rival those of some volcano eruptions.
Megafires in British Columbia in 2017 and Australia in 2019-2020 injected massive amounts of smoke into the stratosphere, allowing first-ever detailed satellite- and ground-based measurements of such cataclysms. Using that data for validation, a Los Alamos National Laboratory-led team modelled the behaviour and impacts of the smoke as it rose from the lower atmosphere into the high-riding stratosphere, then circulated the globe. The research appeared in the Journal of Geophysical Research -- Atmospheres.
"This is the only time we've tracked the global scale smoke phenomenon with satellite- and ground-based observations, which allows us to improve the model and understand the impact," said Manvendra Dubey, project lead and co-author of the paper published this week in the Journal of Geophysical Research: Atmospheres. "The models and measurements are coming together to enhance predictability."
"As fire regimes change and enter new paradigms of behaviour under future climate change, data from past fires can't be used for prediction and assessment," said Gennaro D'Angelo, a co-author on the paper and research scientist at Los Alamos.
"The models are the only way you can forecast their smoke effects," Dubey said. "For instance, observations of the Australian fire showed that black carbon got a boost from solar heating and rose to 30 kilometers in the stratosphere, which made the plume last longer, about 16 months. Our model accounts for this self-heating phenomenon predicted by the late Robert C. Malone at Los Alamos in the 1980s -- and our new study unequivocally validates it."
Plumes have cooling effect
The 2019-2020 Australian megafire injected huge amounts of smoke and soot into the atmosphere that were observed, with global impacts on temperature as this study shows. Shading from the Australian plume lasted a few months. That effect lowered temperatures in the southern hemisphere about 0.2 degrees Celsius, information that has implications for global climate change models.
The smaller plume from the 2017 British Columbia fires did not trigger similar cooling. The study highlights when and how megafire smoke impacts global climate, much like volcanic sulphate and ash injections do.
Recent megafires in Australia and British Columbia have injected unprecedented amounts of smoke into the stratosphere. Modelling led by Los Alamos National Laboratory will help predict the effects of similar future events. Credit: David Peterson, FIREX-AQ
Gennaro D’Angelo, Steve Guimond, Jon Reisner, David A. Peterson, Manvendra Dubey. Contrasting Stratospheric Smoke Mass and Lifetime From 2017 Canadian and 2019/2020 Australian Megafires: Global Simulations and Satellite Observations. Journal of Geophysical Research: Atmospheres, 2022; 127 (10) DOI: 10.1029/2021JD036249
Scientists identify characteristics to better define long COVID
May 17, 2022
A research team supported by the National Institutes of Health has identified characteristics of people with long COVID and those likely to have it. Scientists, using machine learning techniques, analyzed an unprecedented collection of electronic health records (EHRs) available for COVID-19 research to better identify who has long COVID. Exploring de-identified EHR data in the National COVID Cohort Collaborative (N3C), a national, centralized public database led by NIH's National Center for Advancing Translational Sciences (NCATS), the team used the data to find more than 100,000 likely long COVID cases as of October 2021 (as of May 2022, the count is more than 200,000). The findings appeared May 16 in The Lancet Digital Health.
Long COVID is marked by wide-ranging symptoms, including shortness of breath, fatigue, fever, headaches, "brain fog" and other neurological problems. Such symptoms can last for many months or longer after an initial COVID-19 diagnosis. One reason long COVID is difficult to identify is that many of its symptoms are similar to those of other diseases and conditions. A better characterization of long COVID could lead to improved diagnoses and new therapeutic approaches.
"It made sense to take advantage of modern data analysis tools and a unique big data resource like N3C, where many features of long COVID can be represented," said co-author Emily Pfaff, Ph.D., a clinical informaticist at the University of North Carolina at Chapel Hill.
The N3C data enclave currently includes information representing more than 13 million people nationwide, including nearly 5 million COVID-19-positive cases. The resource enables rapid research on emerging questions about COVID-19 vaccines, therapies, risk factors and health outcomes.
The new research is part of a related, larger trans-NIH initiative, Researching COVID to Enhance Recovery (RECOVER), which aims to improve the understanding of the long-term effects of COVID-19, called post-acute sequelae of SARS-CoV-2 infection (PASC). RECOVER will accurately identify people with PASC and develop approaches for its prevention and treatment. The program also will answer critical research questions about the long-term effects of COVID through clinical trials, longitudinal observational studies, and more.
In the Lancet study, Pfaff, Melissa Haendel, Ph.D., at the University of Colorado Anschutz Medical Campus, and their colleagues examined patient demographics, health care use, diagnoses and medications in the health records of 97,995 adult COVID-19 patients in the N3C. They used this information, along with data on nearly 600 long COVID patients from three long COVID clinics, to create three machine learning models to identify long COVID patients.
In machine learning, scientists "train" computational methods to rapidly sift through large amounts of data to reveal new insights -- in this case, about long COVID. The models looked for patterns in the data that could help researchers both understand patient characteristics and better identify individuals with the condition.
The models focused on identifying potential long COVID patients among three groups in the N3C database: All COVID-19 patients, patients hospitalized with COVID-19, and patients who had COVID-19 but were not hospitalized. The models proved to be accurate, as people identified as at risk for long COVID were similar to patients seen at long COVID clinics. The machine learning systems classified approximately 100,000 patients in the N3C database whose profiles were close matches to those with long COVID.
"Once you're able to determine who has long COVID in a large database of people, you can begin to ask questions about those people," said Josh Fessel, M.D., Ph.D., senior clinical advisor at NCATS and a scientific program lead in RECOVER. "Was there something different about those people before they developed long COVID? Did they have certain risk factors? Was there something about how they were treated during acute COVID that might have increased or decreased their risk for long COVID?"
The models searched for common features, including new medications, doctor visits and new symptoms, in patients with a positive COVID diagnosis who were at least 90 days out from their acute infection. The models identified patients as having long COVID if they went to a long COVID clinic or demonstrated long COVID symptoms and likely had the condition but hadn't been diagnosed.
"We want to incorporate the new patterns we're seeing with the diagnosis code for COVID and include it in our models to try to improve their performance," said the University of Colorado's Haendel. "The models can learn from a greater variety of patients and become more accurate. We hope we can use our long COVID patient classifier for clinical trial recruitment."
Transmission electron micrograph of SARS-CoV-2 virus particles, isolated from a patient. Image captured and colour-enhanced at the NIAID Integrated Research Facility (IRF) in Fort Detrick, Maryland. (NIAID)
Emily R Pfaff, Andrew T Girvin, Tellen D Bennett, Abhishek Bhatia, Ian M Brooks, Rachel R Deer, Jonathan P Dekermanjian, Sarah Elizabeth Jolley, Michael G Kahn, Kristin Kostka, Julie A McMurry, Richard Moffitt, Anita Walden, Christopher G Chute, Melissa A Haendel, Carolyn Bramante, David Dorr, Michele Morris, Ann M Parker, Hythem Sidky, Ken Gersing, Stephanie Hong, Emily Niehaus. Identifying who has long COVID in the USA: a machine learning approach using N3C data. The Lancet Digital Health, 2022; DOI: 10.1016/S2589-7500(22)00048-6