How the major Swedish forest fire of 2014 affected the ecosystem

UPPSALA UNIVERSITY

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IMAGE: HÄLLESKOGSBRÄNNAN, VÄSTMANLAND, SWEDEN, THREE MONTHS AFTER THE FIRE IN 2014. ALMOST ALL ORGANIC SOIL IN THE AREA WAS LOST, WHICH RELEASED LARGE AMOUNTS OF CARBON AND NITROGEN.... view more 

CREDIT: JOACHIM STRENGBOM

Swedish researchers from institutions including Uppsala University have spent four years gathering data from the areas affected by the major forest fire of 2014. In their study of how the ecosystem as a whole has been altered, they could see that water quality in watercourses quickly returned to normal, while forested areas continued to lose carbon for many years after the fire.

The consequences of major forest fires remain poorly studied in Northern Europe. To improve this situation, researchers from Uppsala University, the Swedish University of Agricultural Sciences (SLU) and the Swedish Meteorological and Hydrological Institute (SMHI) decided to investigate just how much carbon and nutrients are released into the atmosphere and watercourses during fires and how quickly the ecosystem returns to its previous state. The results of this research are now being presented in the scientific journal Biogeosciences.

The 2014 fire in the Swedish province Västmanland was particularly ferocious, burning both woodland and wetland. Only in a few areas did the trees survive.

"It is not however the trees that release carbon during fires in coniferous forests. Only some of the needles and small branches up in the trees burn, while around 90% of losses come from organic soil, the so-called humus layer. Ditched peatlands that dry a great deal of organic material in the soil are therefore large point sources for emissions from the landscape. This makes it important to measure how deep the burning goes in the ground in order to estimate carbon emissions after a forest fire. We had the opportunity to do just that over a wide area in Västmanland," says Uppsala University researcher Gustaf Granath, lead author of the study.

The loss of the humus layer releases large amounts of carbon and nitrogen from woodland and risks other nutrients leaching out after the fire. It is therefore important that vegetation can quickly re-establish itself in the interests of retaining nutrients and restoring soil carbon.

The results from Västmanland demonstrate that during the fire between 145 and 160 tonnes of carbon dioxide was lost to the atmosphere per hectare. For the whole burned area this is equivalent to 10% of the carbon dioxide emitted annually by Sweden's domestic transport sector. Due to the lack of vegetation after the fire, the soil continued to lose carbon over the next few years, with a net uptake of carbon first noted during a summer month three years after the fire. Researchers were concerned that a great deal of carbon would be lost to watercourses after the fire but were unable to observe any such additional export of carbon into streams when comparing conditions before and after the fire.

Quantities of nutrients such as nitrogen and phosphorus did however increase in streams and lakes after the fire, reaching a peak within one to two months of the fire before declining over time. For many of these substances, in the region of five times as much was transported away during the first year after the fire compared to before; however, most values had returned to normal one to two years after the fire.

"This rapid leaching of nutrients after the fire is due to the lack of vegetation that could absorb the substances, as well as the large release of the substances during the fire as organic soil burned. Without living vegetation and organic soil, water flows in streams increased by 50%" explains Stephan Köhler, professor of environmental geochemistry at SLU, who initiated the measurement of water quality immediately after the fire.

Other studies have shown how vegetation in the area of forest fires has re-established itself and how carbon and nutrient stocks have been rebuilt. How quickly this happens and what parameters affect the process will influence whether or not Sweden's forests could become long-term sources of CO2 to the atmosphere, is something that the researchers intend to continue studying in the area.

"While we now know more about how much and where carbon and nutrients disappear in fires, what happens next is equally interesting. There is a great deal of carbon bound in dead trees that will soon begin to decompose, while at the same time the soil and vegetation will store new carbon and build up stocks of nitrogen. It's important to follow this if we are to understand how our forests are affected when they burn," says Gustaf Granath.

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The study has been funded by the Swedish Agency for Marine and Water Management and Formas.

CAPTION

Three years after the fire at Hälleskogsbrännan, Västmanland, Sweden, a lot of vegatation has has re-established itself.

CREDIT

Gustaf Granath

Trust among corvids

UNIVERSITY OF KONSTANZ

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IMAGE: A PAIR OF SIBERIAN JAYS FORAGING IN THE STUDY POPULATION IN SWEDISH LAPLAND. view more 

CREDIT: MICHAEL GRIESSER

Siberian jays are group living birds within the corvid family that employ a wide repertoire of calls to warn each other of predators. Sporadically, however, birds use one of these calls to trick their neighbouring conspecifics and gain access to their food. Researchers from the universities of Konstanz (Germany), Wageningen (Netherlands), and Zurich (Switzerland) have now examined how Siberian jays avoid being deceived by their neighbours. The study, published in the journal Science Advances, shows that these birds have great trust in the warning calls from members of their own group, but mainly ignore such calls from conspecifics of neighbouring territories. Thus, the birds use social information to differentiate between trustworthy and presumably false warning calls. Similar mechanisms could have played a role in the formation of human language diversity and especially in the formation of dialects.

Deception and lies

Deception and lies are surprising aspects of human communication and the use of language in which false information is intentionally communicated to others, allowing an individual to gain an advantage over the recipient of such false information. However, language is actually highly pro-social and cooperative and is mainly used to share reliable information. Thus, language can only function properly and be maintained if deception is kept to a minimum or other mechanisms are in place to recognize and avoid deception.

People do judge the reliability of communication partners based on personal experience. "If someone repeatedly lies to you, you will most likely stop trusting this person very quickly," says Dr Michael Griesser, a biologist at the University of Konstanz. Griesser authored the study together with Dr Filipe Cunha, whose doctoral thesis he supervised. But do we observe deception in animals as well, and, if so, which mechanisms do animals use to avoid being deceived?

Warning calls of the Siberian jay

Indeed, a number of species are able to deceive their conspecifics, including some species of primates and birds like the Siberian jay (Perisoreus infaustus). Siberian jays live in territorial groups and have an elaborate communication system: A wide range of calls allow them to warn each other of the presence of different predators as well as the behaviour of their fiercest enemy, the hawk.

Occasionally, however, neighbours intruding into a group's territory use the same calls that would otherwise indicate the presence of a perched hawk for a different purpose. Their aim is to deceive the members of the group about the presence of the predator, thus scaring them away to get access to their food. "It is a commonly observed phenomenon in the animal kingdom that warning calls are used to deceive others. Clearly, the recipients of the false information potentially pay a high price if they ignore the warning," says Cunha.

Only trust those you know?

To find out how Siberian jays identify and respond to this type of deception, the researchers examined a population of wild Siberian jays in northern Sweden. They attracted experienced individuals to a feeding site and recorded video footage of what happened. As soon as such an experienced individual visited the feeder, a loudspeaker played recordings of Siberian jays' warning calls designating a perched hawk. These calls were recordings from former members of the visitor's own group, birds from neighbouring territories, or birds that the visitor had never encountered before. Using the video recordings, the researchers measured how long it took the visitor to leave and return to the feeder.

These "playback experiments" demonstrated that experienced Siberian jays responded quicker and took longer to return to the feeder when hearing warning calls of a former member of their own group than when exposed to warning calls of neighbouring groups or previously unknown individuals. "Siberian jays thus have a simple rule to avoid being tricked: They only trust the warning calls from members of their own group, meaning cooperation partners. Familiarity alone is not enough, otherwise the birds would also have trusted the calls of their neighbours," Griesser explains.

Deception as a possible factor in language and dialect formation

Michael Griesser draws a comparison to humans and their languages and dialects. Just like Siberian jays, humans preferentially trust others who belong to the same group as themselves and therefore more likely are cooperation partners. "It could thus very well be the case that vulnerability to deception has been a driver of the rapid diversification of human languages and facilitating the formation of dialects as they allow the identification of local cooperation partners," Griesser considers.

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Key facts:

• Study: Filipe C. R. Cunha, Michael Griesser (2021) Who do you trust? Wild birds use social knowledge to avoid being deceived. Science Advances; DOI: 10.1126/sciadv.aba2862
• Siberian jays use social information to avoid being deceived by neighbours. The birds reacted exclusively to the warning calls of cooperation partners from their own group and ignored the warning calls of others.
• Similar mechanisms could have played a role in the diversification of human languages and especially in the formation of dialects.
• Dr Michael Griesser is an affiliate member of the "Centre for the Advanced Study of Collective Behaviour" and a researcher in the Department of Biology at the University of Konstanz. The study was completed when Griesser worked as a researcher at the University of Zurich.
• Funding was provided by the Swiss National Science Foundation, via the EU Framework Programme for Research and Innovation, Horizon 2020, the University of Zurich and the Science Without Borders Programme in Brazil.

Note to editors:

You can download a photo here: https://cms. uni-konstanz. de/fileadmin/pi/fileserver/2021/vertrauen_bei_rabenvoegeln. jpg
Caption: A pair of Siberian jays foraging in the study population in Swedish Lapland.
Copyright: Michael Griess

Taking a bite out of tooth evolution: Frogs have lost teeth more than 20 times

FLORIDA MUSEUM OF NATURAL HISTORY

Research News

IMAGE: SOME FROG SPECIES HAVE TEETH WHILE OTHERS ARE TOOTHLESS. STILL OTHERS HAVE A COMBINATION OF TRUE TEETH AND TOOTHLIKE STRUCTURES. THE SOLOMON ISLAND LEAF FROG, CORNUFER GUENTHERI, HAS TRUE TEETH... view more 

CREDIT: DANIEL PALUH/FLORIDA MUSEUM OF NATURAL HISTORY

GAINESVILLE, Fla. --- Scientists have long known that frogs are oddballs when it comes to teeth. Some have tiny teeth on their upper jaws and the roof of their mouths while others sport fanglike structures. Some species are completely toothless. And only one frog, out of the more-than 7,000 species, has true teeth on both upper and lower jaws.

Now, the first comprehensive study of tooth evolution in frogs is bringing the group's dental history into focus. Florida Museum of Natural History researchers analyzed CT scans of nearly every living amphibian genus to reveal that frogs have lost teeth over 20 times during their evolution, more than any other vertebrate group. Some frog species may have even re-evolved teeth after losing them millions of years before.

Researchers also found a correlation between the absence of teeth in frogs and a specialized diet on small insects, such as ants and termites. Their analysis of frogs' amphibian relatives, the salamanders and obscure wormlike animals known as caecilians, showed these groups retained teeth on both upper and lower jaws throughout their evolutionary history.

"Through this study, we have really been able to show that tooth loss in vertebrates is largely a story about frogs, with over 20 independent losses," said lead study author Daniel Paluh, a Ph.D. candidate in the University of Florida's department of biology. "Only eight other groups of living vertebrates, including seahorses, turtles, birds and a few mammals, have also evolved toothlessness."

Teeth first evolved more than 400 million years ago, quickly conferring a competitive advantage to animals that had them and leading to the diversification of sharks, bony fish and ultimately the vertebrates that first roamed onto land.

Throughout their long history, teeth have been an important component of vertebrate evolution, yet some groups have done equally well without them. Birds lost their teeth around 100 million years ago with the advent of the beak, and both the largest known vertebrate, the blue whale, and the smallest, a frog from New Guinea, are entirely toothless.

Few researchers have focused on studying frog teeth, however, for the simple reason that they're incredibly small.

"If you open a frog's mouth, chances are you will not see teeth even if they have them, because they're usually less than a millimeter long," or smaller than the tip of a pencil, Paluh said.

That hasn't stopped some people from trying. In his study of the relationships between frog species, the famous 19th-century paleontologist Edward Cope lumped all toothless frogs into the same group, which he called Bufoniformia.

Researchers using modern genetic techniques have since shown that species in Bufoniformia aren't actually closely related, suggesting that the loss of teeth occurred more than once in frog evolution. But there the story stalled.

In the past, accurately determining which frogs had teeth would have required laborious work that irrevocably damaged or destroyed portions of preserved specimens. Frogs are also a highly diverse group, making a comprehensive assessment of their teeth a difficult task.

But Paluh and his colleagues had one major advantage: The Florida Museum leads a massive multi-institutional effort to CT scan 20,000 vertebrate specimens, giving researchers the ability to study animals in ways not previously possible.

The project, called oVert, allows anyone with an Internet connection to access 3D models derived from the scans, which depict distinct features of an organism, including bones, vasculature, internal organs, muscle tissue - and teeth. For Paluh, it meant he could virtually peer into the gape of a frog.

Working remotely during COVID-19 lockdowns, Paluh and fellow members of the museum's Blackburn Lab used oVert scans to carry out the study. To get the clearest picture of changes in teeth over time, the researchers included representatives of all amphibian groups. They analyzed patterns of tooth loss through time using a previously published map of evolutionary relationships between amphibians based on genetic data.

The study provides a powerful example of the research that can be accomplished with open-access data, said David Blackburn, Florida Museum curator of herpetology, Paluh's adviser and senior author of the study.

"We effectively crowdsourced the data collection across our lab, including people that were not in the U.S. at that time," Blackburn said.

Their results showed that far from losing teeth once during their evolution, as suggested by the now-debunked idea of the Bufoniformia, frogs have undergone "rampant tooth loss," Paluh said, with toothlessness popping up in groups as distantly related as toads and poison dart frogs.

The team also noted a tight correlation between the presence or absence of teeth in frogs and their eating habits. While dietary information is scant for many species of frogs, the researchers uncovered a connection between a diet of tiny insects and a lack of teeth.

"Having those teeth on the jaw to capture and hold on to prey becomes less important because they're eating really small invertebrates that they can just bring into their mouth with their highly modified tongue," said Paluh. "That seems to relax the selective pressures that are maintaining teeth."

Some species of poison dart frogs, for example, have evolved to feed mostly on ants and mites that produce toxic compounds, using their sticky, projectile tongues to scoop up their prey and swallow it whole. The frogs are able to store the toxins from their food source and repurpose them for their own use, secreting the compounds through their skin to ward off predators. And the turtle frog, a toothless burrowing species in Australia, tunnels through the maze of underground passages inside termite nests, hunting the insects that constructed them.

Teeth seem to be superfluous for mammals that feed on ants and termites as well. Pangolins and anteaters, which have highly specialized tongues for probing ant and termite nests, are both toothless.

Many questions remain about frogs' tooth biology, including how the genes that regulate their tooth production turn on and off. It's also unclear whether the serrated toothlike structures in frogs that regained these features are actually real teeth, Paluh said. To determine that, scientists will need to take a more in-depth look at these structures, looking for the presence of enamel and other key defining features.

Innovative techniques, such as those used in the oVert project, are beginning to underscore knowledge gaps and limitations like these, but they also open up the field to new discoveries, Blackburn said.

"We now have lots of new questions in my lab inspired by the surprising things turning up from 3D imaging from the oVert project, and those will lead us both back into museum collections and to the field to see what these animals are doing in the wild."

CAPTION

Researchers found a high correlation between a diet of small insects and a lack of teeth in frogs. The strawberry poison frog, Oophaga pumilio, is a toothless species that eats ants and termites.

CREDIT

Daniel Paluh/Florida Museum of Natural History

Other study co-authors are the Florida Museum's Karina Riddell, Maggie Hantak, Gregory Jongsma, Rachel Keeffe, Stuart Nielsen, María Camila Vallejo-Pareja and Edward Stanley, Catherine Early of the Florida Museum and the Science Museum of Minnesota and Fernanda Magalhães Silva of the Florida Museum and the Federal University of Pará.

Blackburn noted that Riddell, who recently graduated from UF with a bachelor's degree from the College of Health and Human Performance, played a key role in collecting data for the project.

 

Study: Parler provided echo chamber for vaccine misinformation, conspiracy theories

Analysis shows posters followed themes; can help guide future health communications

UNIVERSITY OF KANSAS

Research News

 

LAWRENCE -- In the early days of COVID-19 vaccine development, a new social media platform provided a place for like-minded people to discuss vaccines, share misinformation and speculate about the motivations for its development. A new study from the University of Kansas shows people flocked to Parler to discuss the vaccines in an echo chamber-type environment, and those conversations can shed light about how to communicate about vaccine efficacy during health crises.

COVID-19 vaccine vial and syringe photo from the U.S. Census Bureau.In the runup to the 2020 election, then-president Donald Trump claimed a COVID-19 vaccine could be ready before people went to the polls. About that time, millions were flocking to Parler, a new social media platform that promised a free speech environment via unregulated posts. A trio of KU doctoral students in journalism & mass communications analyzed a sample of 400 posts on the platform between November 2020 and January 2021 about the vaccines. Results showed people followed messages of conservative political leaders, shared misinformation and reinforced messages shedding doubt on vaccine efficacy.

"Around October last year, we were hearing a lot of buzz around a new social media platform, Parler, not just in the political field, but in the health field as well," said Annalise Baines, the study's lead author. "We wanted to understand more about what was being said about COVID-19 vaccines specifically, as we noticed a shift in the conversation from developing vaccines to distrusting science around the efficacy of vaccines."

The study, co-written by Baines, Muhammad Ittefaq and Mauryne Abwao, was published in the journal Vaccines.

A thematic analysis of the posts, known as "parleys," showed users discussing the vaccines in five distinct themes:

• Reasons to refuse the vaccine
• Side effects
• Population control through the vaccines
• Children getting vaccinated without parental consent
• Comparison of other health issues with COVID-19

Previous research has extensively examined communication via social media, but Parler, a relatively new platform that has undergone controversy and was deplatformed for several weeks following the Jan. 6 insurrection at the U.S. Capitol, has not been studied widely. The authors, who study environmental, health communications, and new social and digital media topics, analyzed how people discussed vaccines, an important public health issue, among like-minded individuals. While the research didn't compare users' political leanings, the platform was widely popular with conservative users and was touted as an alternative to sites such as Twitter or Facebook, which they accused of anti-conservative bias.

"If you live in a bubble in which you only hear from people who share the same views as you and information that supports that, that tends to reinforce what you already believe in. It's also about people you trust. We didn't have demographic information on users, but we did find echo chambers existed there, and people even used the hashtag #echo," Ittefaq said.

Among the five key themes, users frequently used hashtags to further spread their content, such as #nocovidvaccine, #novaccine, #wedonotconsent, #vaxaware, #wakeupworld. Users also shared polls showing people in the U.S. and Europe didn't want a vaccine, or they shared dubiously sourced news stories about nurses who suffered from Bell's palsy after getting the dose. This finding also appeared in the second most frequent theme regarding side effects. Users shared posts about people dying after receiving the vaccine or who had cognitive effects or were hospitalized.

"Some of the reasons for vaccine hesitancy are deemed legit, and the major concerns may have been a result of people being skeptical of the side effects," Abwao said. "Currently, we have experienced cases where some vaccines have been discontinued; however, this should not deter people from getting vaccinated."

One of the most popular conspiracy theories shared was that vaccines were being developed as a means for government or a new world order to control the population, according to the KU researchers. Frequent conspiracies involved the use of microchips via the vaccine or an enzyme that would control the population, the study found. People often included links, videos and images with such parleys, though when sources were included they were from unverified sites or contained videos that were purported to be leaked from the government. In other themes, users shared posts claiming schools would vaccinate children without parents' consent or cast doubt on the pandemic's severity, comparing it to other health issues such as the flu, or citing abortion statistics to claim it was not as deadly as commonly reported. Common hashtags in those themes included #scamdemic, #plandemic, #idonotconsent, #covidhoax and #nocovidvaccine.

The findings illustrate several key points in health communications and social media use, the authors said. People listen to the messages of elected officials and will adhere to them, such as Trump calling the virus a hoax or U.S. Sen. Ted Cruz's endorsement of Parler as a place to share opinions on current issues. The views shared by people can not only spread misinformation but can also be informative for policymakers and public health officials to counter anti-vaccination rhetoric, the KU researchers said. On the Parler platform anyone can post claims online without going through verification steps and share that information with others. This can be dangerous, especially for those who might be more vulnerable and not be able to identify misinformation, Baines said.

Public health officials have a difficult job in which they are trained to perform science and share findings, not to combat misinformation, Ittefaq said. But, if they are able to use credible information through stories of individuals and trusted experts, they can help disseminate credible information on health crises to the public. Failing to do so can have negative ramifications in future public health crises, he added. The analysis shows people listen to those similar to themselves, and that if public health officials can share valid information with people who can share it with their peers, they will have greater success in situations such as the COVID-19 pandemic, in which people continue to seek valid information about the vaccines.

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Chip inserted under the skin may better identify patients at risk of recurrent stroke

STROKE AF trial results indicate that an inserted chip can improve detection of irregular heart rate

MASSACHUSETTS GENERAL HOSPITAL

Research News

BOSTON - For patients who have experienced certain common types of stroke, a small chip inserted under the skin may help physicians predict their likelihood of experiencing a second stroke, and therefore their likelihood of benefiting from preventive therapy. The findings come from a recent clinical trial published in the Journal of the American Medical Association and led by investigators at Massachusetts General Hospital (MGH) and Northwestern University Feinberg School of Medicine.

Each year, approximately 800,000 strokes occur in the United States, and as many as one-fourth occur in people who experienced a previous stroke. Investigators have been searching for ways to identify patients who are likely to experience a recurrent stroke, as these individuals could be candidates for taking certain medications such as blood thinners. One group of patients who face an elevated risk of recurrent strokes are those with atrial fibrillation--an irregular and often rapid heart rate--that often goes undetected and untreated. (Irregular heartbeats can allow blood to pool in the heart, which can cause clots to form and travel to the brain.)

Recent research has shown that a small chip inserted under the skin can monitor the heart rate and rhythm, and help physicians detect atrial fibrillation in patients who previously experienced what's called a cryptogenic stroke, one with no identified cause despite thorough patient testing. Now investigators have tested the chip--less than 1¾? long and 1/6? thick and called an insertable cardiac monitor--in patients who experienced a stroke caused by narrowing of a large artery like the carotid artery, or blockage of a small artery deep in the brain where atrial fibrillation would be unexpected.

In the Stroke of Known Cause and Underlying Atrial Fibrillation (STROKE AF) trial, 492 patients were randomized and completed 12 months of follow-up after receiving either an insertable cardiac monitor within 10 days of an initial stroke or usual care consisting of external cardiac monitoring through electrocardiograms or other tracking methods.?

The chip detected atrial fibrillation in 12.1% of patients, compared with 1.8% detected through usual care. The team noted that the episodes of atrial fibrillation were not brief, with most lasting at least one hour. Most stroke experts would recommend that patients with this degree of atrial fibrillation start taking blood thinners to prevent a future stroke.

"We found that a significant minority of patients with stroke not thought to be related to atrial fibrillation actually have atrial fibrillation, but we can only find it with an implantable monitor," says lead author Richard A. Bernstein, MD, PhD, a professor of Neurology at Northwestern University Feinberg School of Medicine.

Adds senior author Lee H. Schwamm, MD, C. Miller Fisher Chair of Vascular Neurology at MGH: "Based on the study findings, we believe that patients with stroke who are similar to those in the STROKE AF Trial should now undergo long-term cardiac monitoring with an insertable cardiac monitor to identify unsuspected atrial fibrillation."

Schwamm notes that for every eight patients monitored, clinicians could expect to find atrial fibrillation in one of them in the first year. "This could dramatically change the treatment recommendations by their doctor," he says.

Next steps in this research include identifying patient factors that predict the development of atrial fibrillation and the duration and extent of the arrhythmia. Additional studies are being explored to further understand the association of silent atrial fibrillation and recurrent stroke of all types.

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Schwamm is professor of Neurology at Harvard Medical School and vice president of Virtual Care at Mass General Brigham. Co-authors are Hooman Kamel, MD, of Weill Cornell Medicine in New York City; Christopher B. Granger, MD, and Jonathan P. Piccini, MD, of Duke University Medical Center; Pramod P. Sethi, MD, of Cone Health Stroke Center and Guilford Neurologic Research Associates in Greensboro, North Carolina; Jeffrey M. Katz, MD, of North Shore University Hospital in Manhasset, New York; and Carola Alfaro Vives, MS, Paul D. Ziegler, MS, and Noreli C. Franco, PhD, of Medtronic.

This study was supported by Medtronic.

About the Massachusetts General Hospital

Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The Mass General Research Institute conducts the largest hospital-based research program in the nation, with annual research operations of more than $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments. In August 2020, Mass General was named #6 in the U.S. News & World Report list of "America's Best Hospitals."

Better popping potential for popcorn

AMERICAN SOCIETY OF AGRONOMY

Research News

 

IMAGE: THE RESEARCH TEAM OBSERVED 49 DIFFERENT VARIETIES OF POPCORN INCLUDING WHITE POPCORN, YELLOW POPCORN, PURPLE POPCORN, AND BLACK POPCORN TO DETERMINE ECONOMICAL WAYS TO CREATE HIGH-QUALITY POPCORN. view more 

CREDIT: MARIA FERNANDA MAIOLI

Popcorn. What would movies and sporting events without this salty, buttery snack? America's love for this snack goes beyond these events. We consume 15 billion quarts of popped popcorn each year.

When it comes to popcorn, consumers want a seed-to-snack treat that leaves more snacks than seeds when popped. This means when they pop the corn, there shouldn't be many unpopped kernels left in the bowl.

Maria Fernanda Maioli set out to determine the properties affecting popping expansion in popcorn. The team's research was recently published in Agronomy Journal, a publication of the American Society of Agronomy.

"The way kernels expand is a basic, yet very important characteristic of popcorn," says Fernanda Maioli. This is referred to as "expansion ratio."

"Very hard grains burst when heated. This expansion multiplies the initial volume of the grains by more than 40 times. In the case of popcorn, it produces a unique and tasty food."

The major factors that influence popcorn quality are kernel moisture, expansion ratios, and popping ratios. Higher quality popcorn is associated with kernels that expand more. This popped corn has a better texture and softness.

CAPTION

Yellow popcorn is the type most people are familiar with. This is the type commonly used by movie theaters.

CREDIT

Maria Fernanda Maioli

There have been several past studies on the ways popcorn kernel expand. These studies report that popping expansion has a strong association with higher starch content in kernels.

Previous research also shows that popcorn varieties with a thicker protective outer seed coating - have a greater expansion ratio.

Popping ability is also affected by how well the starchy substance inside kernels transfer heat during the popping process. Fernanda Maioli and her team's study measured this performance, which makes this research unique.

"We observed how this heat transfer inside the popcorn kernel relates to the expansion ratio," she adds. "It allowed us to understand how other characteristics may also relate to expansion."

"The purpose of our study was to identify popcorn characteristics related to expansion," says Fernanda Maioli. "This will help us efficiently identify popcorn varieties with good agronomic characteristics as well as good popping quality."

The team evaluated 49 types of popcorn for different traits. The traits included grain yield, kernel length, popping expansion, kernel and protective layer thickness, heat transfer ability, and the amount of protein in kernels.

Then the researchers studied the influence of those characteristics on the popping expansion.

"Our results showed that the thickness of the kernel's outer layer is a key trait for selecting popcorn with greater popping expansion," says Fernanda Maioli.

Understanding which popcorn traits are related to the expansion capacity will help future researchers identify and breed high quality popcorn. Researchers will not need to spend time and money to look at other unrelated characteristics.

The team hopes they can identify relationships between other key traits. Future research will continue to improve the tasty, buttery snack.

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Maria Fernanda Maioli is a researcher at the State University of Maringá in Brazil.

CAPTION

Purple popcorn kernels have a gorgeous hue and contain more antioxidants than traditional yellow kernels.

CREDIT

Maria Fernanda Maioli

How AI could alert firefighters of imminent danger

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY (NIST)

Research News

 

IMAGE: NIST FIREFIGHTERS DOUSE FLAMES BURSTING FROM A BUILDING AS A FLASHOVER OCCURS DURING AN EXPERIMENT. view more 

CREDIT: NIST

Firefighting is a race against time. Exactly how much time? For firefighters, that part is often unclear. Building fires can turn from bad to deadly in an instant, and the warning signs are frequently difficult to discern amid the mayhem of an inferno.

Seeking to remove this major blind spot, researchers at the National Institute of Standards and Technology (NIST) have developed P-Flash, or the Prediction Model for Flashover. The artificial-intelligence-powered tool was designed to predict and warn of a deadly phenomenon in burning buildings known as flashover, when flammable materials in a room ignite almost simultaneously, producing a blaze only limited in size by available oxygen. The tool's predictions are based on temperature data from a building's heat detectors, and, remarkably, it is designed to operate even after heat detectors begin to fail, making do with the remaining devices.

The team tested P-Flash's ability to predict imminent flashovers in over a thousand simulated fires and more than a dozen real-world fires. Research, just published in the Proceedings of the AAAI Conference on Artificial Intelligence, suggests the model shows promise in anticipating simulated flashovers and shows how real-world data helped the researchers identify an unmodeled physical phenomenon that if addressed could improve the tool's forecasting in actual fires. With further development, P-Flash could enhance the ability of firefighters to hone their real-time tactics, helping them save building occupants as well as themselves.

Flashovers are so dangerous in part because it's challenging to see them coming. There are indicators to watch, such as increasingly intense heat or flames rolling across the ceiling. However, these signs can be easy to miss in many situations, such as when a firefighter is searching for trapped victims with heavy equipment in tow and smoke obscuring the view. And from the outside, as firefighters approach a scene, the conditions inside are even less clear.

"I don't think the fire service has many tools technology-wise that predict flashover at the scene," said NIST researcher Christopher Brown, who also serves as a volunteer firefighter. "Our biggest tool is just observation, and that can be very deceiving. Things look one way on the outside, and when you get inside, it could be quite different."

Computer models that predict flashover based on temperature are not entirely new, but until now, they have relied on constant streams of temperature data, which are obtainable in a lab but not guaranteed during a real fire.

Heat detectors, which are commonly installed in commercial buildings and can be used in homes alongside smoke alarms, are for the most part expected to operate only at temperatures up to 150 degrees Celsius (302 degrees Fahrenheit), far below the 600 degrees Celsius (1,100 degrees Fahrenheit) at which a flashover typically begins to occur. To bridge the gap created by lost data, NIST researchers applied a form of artificial intelligence known as machine learning.

"You lose the data, but you've got the trend up to where the heat detector fails, and you've got other detectors. With machine learning, you could use that data as a jumping-off point to extrapolate whether flashover is going to occur or already occurred," said NIST chemical engineer Thomas Cleary, a co-author of the study.

Machine-learning algorithms uncover patterns in large datasets and build models based on their findings. These models can be useful for predicting certain outcomes, such as how much time will pass before a room is engulfed in flames.

To build P-Flash, the authors fed their algorithm temperature data from heat detectors in a burning three-bedroom, one-story ranch-style home -- the most common type of home in a majority of states. This building was of a digital rather than brick-and-mortar variety, however.

Because machine learning algorithms require great quantities of data, and conducting hundreds of large-scale fire tests was not feasible, the team burned this virtual building repeatedly using NIST's Consolidated Model of Fire and Smoke Transport, or CFAST, a fire modeling program validated by real fire experiments, Cleary said.

The authors ran 5,041 simulations, with slight but critical variations between each. Different pieces of furniture throughout the house ignited with every run. Windows and bedroom doors were randomly configured to be open or closed. And the front door, which always started closed, opened up at some point to represent evacuating occupants. Heat detectors placed in the rooms produced temperature data until they were inevitably disabled by the intense heat.

To learn about P-Flash's ability to predict flashovers after heat detectors fail, the researchers split up the simulated temperature recordings, allowing the algorithm to learn from a set of 4,033 while keeping the others out of sight. Once P-Flash had wrapped up a study session, the team quizzed it on a set of 504 simulations, fine-tuned the model based on its grade and repeated the process. After attaining a desired performance, the researchers put P-Flash up against a final set of 504.

The researchers found that the model correctly predicted flashovers one minute beforehand for about 86% of the simulated fires. Another important aspect of P-Flash's performance was that even when it missed the mark, it mostly did so by producing false positives -- predictions that an event would happen earlier than it actually did -- which is better than the alternative of giving firefighters a false sense of security.

"You always want to be on the safe side. Even though we can accept a small number of false positives, our model development places a premium on minimizing or, better yet, eliminating false negatives," said NIST mechanical engineer and corresponding author Wai Cheong Tam.

The initial tests were promising, but the team had not grown complacent.

"One very important question remained, which was, can our model be trusted if we only train our model using synthetic data?" Tam said.

Luckily, the researchers came across an opportunity to find answers in real-world data produced by Underwriters Laboratories (UL) in a recent study funded by the National Institute of Justice. UL had carried out 13 experiments in a ranch-style home matching the one P-Flash was trained on, and as with the simulations, ignition sources and ventilation varied between each fire.

The NIST team trained P-Flash on thousands of simulations as before, but this time they swapped in temperature data from the UL experiments as the final test. And this time, the predictions played out a bit differently.

P-Flash, attempting to predict flashovers up to 30 seconds beforehand, performed well when fires started in open areas such the kitchen or living room. But when fires started in a bedroom, behind closed doors, the model could almost never tell when flashover was imminent.

The team identified a phenomenon called the enclosure effect as a possible explanation for the sharp drop-off in accuracy. When fires burn in small, closed-off spaces, heat has little ability to dissipate, so temperature rises quickly. However, many of the experiments that form the basis of P-Flash's training material were carried out in open lab spaces, Tam said. As such, temperatures from the UL experiments shot up nearly twice as fast as the synthetic data.

Despite revealing a weak spot in the tool, the team finds the results to be encouraging and a step in the right direction. The researchers' next task is to zero in on the enclosure effect and represent it in simulations. To do that they plan on performing more full-scale experiments themselves.

When its weak spots are patched and its predictions sharpened, the researchers envision that their system could be embedded in hand-held devices able to communicate with detectors in a building through the cloud, Tam said.

Firefighters would not only be able to tell their colleagues when it's time to escape, but they would be able to know danger spots in the building before they arrive and adjust their tactics to maximize their chances of saving lives.

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CAPTION

Researchers simulated more than 5,000 fires in a digital three-bedroom house, with crucial details such as the fire origin varying between each. The team's machine learning-based tool, P-Flash, correctly predicted whether a flashover (a potentially deadly phenomena) occurred 86% of the time based on simulated temperature data.

CREDIT

NIST

Amazon backs marijuana legalization, drops weed testing for some jobs

(Reuters) - Amazon.com Inc said on Tuesday it supports a proposed U.S. legislation to legalize cannabis at the federal level, and would drop weed-testing requirements for some recruitments

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© Reuters/BRENDAN MCDERMID Amazon's JFK8 distribution 

center in Staten Island, New York City

The e-commerce company's public policy team will be actively supporting The Marijuana Opportunity Reinvestment and Expungement Act of 2021 (MORE Act), which seeks to legalize marijuana at the federal level, its consumer boss Dave Clark said in a blog post.

Amazon will also no longer screen its job applicants for marijuana use for any positions not regulated by the Department of Transportation, Clark added.

While many U.S. states have legalized marijuana use, employers have so far largely refused to work with the industry as cannabis is still a classified substance at the federal level.

"In the past, like many employers, we've disqualified people from working at Amazon if they tested positive for marijuana use," Clark said. "However, given where state laws are moving across the U.S., we've changed course."

Amazon was hit with a proposed class action suit, which claimed that the company was violating a New York City law by testing applicants for jobs at local facilities for marijuana, according to a Westlaw report. https://reut.rs/3uHPxM6

The company does not allow marijuana sales on its platform.

Amazon also said it is tweaking its worker productivity tracking tool, "Time off Task."

"Starting today, we're now averaging Time off Task over a longer period to ensure that there's more signal and less noise—reinforcing the original intent of the program," Clark said.

(Reporting by Akriti Sharma in Bengaluru; editing by Uttaresh.V)