Tuesday, October 26, 2021

Fossil dental exams reveal how tusks first evolved

A wide variety of animals have tusks, from elephants and walruses to five-pound, guinea pig-looking critters called hyraxes. But one thing tusked animals have in common is that they're all mammals—there are no known fish, reptiles, or birds with tusks. In a new study in Proceedings of the Royal Society B, paleontologists traced the first tusks back to ancient mammal relatives that lived before the dinosaurs, and to do so, they had to define what makes a tusk a tusk in the first place.

"Tusks are this very famous anatomy, but until I started working on this study, I never really thought about how tusks are restricted to mammals," says Megan Whitney, a researcher at Harvard University and the lead author of the study.

"We were able to show that the first tusks belonged to animals that came before modern mammals, called dicynodonts," says Ken Angielczyk, a curator at Chicago's Field Museum and an author of the paper. "They're very weird animals."

The dicynodonts mostly lived before the time of the dinosaurs, from about 270 to 201 million years ago, and they ranged from rat-sized to elephant-sized. Modern mammals are their closest living relatives, but they looked more reptilian, with turtle-like beaks. And since their discovery 176 years ago, one of their defining features has been the pair of protruding tusks in their upper jaws. The name dicynodont even means "two canine teeth."

The researchers got the idea to study the origin of tusks while taking a lunch break on a paleontological dig. "We were sitting in the field in Zambia, and there were dicynodont teeth everywhere," recalls Whitney. "I remember Ken picking them up and asking how come they were called tusks, because they had features that tusks don't have."

Angielczyk had hit upon a crucial distinction: not all protruding teeth are technically tusks, and the teeth's makeup and growth patterns tell us whether they count. "For this paper, we had to define a tusk, because it's a surprisingly ambiguous term," says Whitney. The researchers decided that for a tooth to be a tusk, it has to extend out past the mouth, it has to keep growing throughout the animal's life, and unlike most mammals' teeth (including ours), tusks' surfaces are made of dentine rather than hard enamel.

Under these parameters, elephants, walruses, warthogs, and hyraxes all have tusks. Other big teeth in the animal kingdom don't make the cut, though. For instance, rodent teeth, even though they sometimes stick out and are ever-growing, have an enamel band on the front of the tooth, so they don't count.

Some of the dicynodont tusks that the team observed in Zambia didn't seem to fit the definition of a tusk either— they were coated in enamel instead of dentine.

The different makeup of teeth versus tusks also gives scientists insights into an animal's life. "Enamel-coated teeth are a different evolutionary strategy than dentine-coated tusks, it's a trade-off," says Whitney. Enamel teeth are tougher than dentine, but because of the geometry of how teeth grow in the jaw, if you want teeth that keep growing throughout your life, you can't have a complete enamel covering.

Animals like humans made an evolutionary investment in durable but hard-to-fix teeth— once our adult teeth grow in, we're out of luck if they get broken. Tusks are less durable than our enamel-coated teeth, but they grow continuously, even if they get damaged. It's like the compromise of getting a car that's very reliable but very difficult to get repaired when it does have trouble, versus driving a beater that needs frequent repairs but is a model that's cheap and easy for any mechanic to fix.

The different kinds of teeth animals have evolved can tell scientists about the pressures those animals faced that could have produced those teeth. Animals with tusks might use them for fighting or for rooting in the ground, exposing them to little injuries that would be risky for enamel teeth that don't grow continuously.

To study whether dicynodonts tusks really were tusks, the researchers cut paper-thin slices out of the fossilized teeth of 19 dicynodont specimens, representing ten different species, and examined their structure with a microscope. They also used micro-CT scans to examine how the teeth were attached to the skull, and whether their roots showed evidence of continuous growth. The scientists found that some dicynodont teeth are indeed tusks, while others, particularly those of some of the earlier species, were just large teeth. It wasn't a strict progression from non-tusks to tusks, though— different members of the dicynodont family evolved tusks independently.

Whitney says she was surprised by the finding. "I kind of expected there to be one point in the family tree where all the dicynodonts started having tusks, so I thought it was pretty shocking that we actually see tusks evolve convergently," she says.

"Dicynodont tusks can tell us a lot about mammalian tusk evolution in general," says Angielczyk. "For instance, this study shows that reduced rates of tooth replacement and a flexible ligament attaching the tooth to the jaw are needed for true tusks to evolve. It all ladders up to giving us a better understanding of the tusks we see in mammals today."

"Dicynodonts were the most abundant and diverse vertebrates on land just before dinosaur times, and they're famous for their 'tusks.' The fact that in reality only a few have true tusks, and the rest have big teeth, is a beautiful example of evolution we can document. We can see how to build a tusk!" says Brandon Peecook, a curator at the Idaho Museum of Natural History and one of the paper's authors.

The researchers say that the study, which shows the earliest known instance of true tusks, could help scientists better understand how evolution works.

"Tusks have evolved a number of times, which makes you wonder how—and why? We now have good data on the anatomical changes that needed to happen for dicynodonts to evolve tusks. For other groups, like warthogs or walruses, the jury is still out," says Christian Sidor, a curator at the University of Washington Burke Museum and one of the paper's authors.

"Despite being extremely weird animals, there are some things about dicynodonts, like the evolution of tusks, that inform us about the mammals around us today," says Angielczyk. "Plus, anytime you can say mammals aren't that special, dicynodonts did it first, that's a good day."Thailand seizes large elephant tusks worth over $450,000

More information: The evolution of the synapsid tusk: insights from dicynodont therapsid tusk histology, Proceedings of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rspb.2021.1670. rspb.royalsocietypublishing.or … .1098/rspb.2021.1670

Journal information: Proceedings of the Royal Society B

Provided by Field Museum

How does 'normal' Internet browsing look today? Now we know

by Daniel Tkacik, Carnegie Mellon University

browser security — Credit: Unsplash/CC0 Public Domain

It's 7:15 am on a Friday morning, and Jordan wants to download an application to their laptop. They know the app by name, or so they think; they open a new tab in their Internet browser and mistype the app's name. The error brings them to a malicious website that looks like a legitimate site, only it isn't, causing Jordan to download an app containing malware. Jordan's computer is now infected with malware.

Jordan is a real person, although their name isn't really Jordan. They were a participant in a new study by CyLab researchers that aimed to learn what "normal" Internet browsing looks like. Such datasets didn't previously exist, but now that one does, researchers can better understand how people like "Jordan" are led to download malicious content and come up with ways to prevent that from happening again.

Their study, titled "How Do Home Computer Users Browse the Web?" was published in the latest issue of ACM Transactions on the Web.

"The goal for this paper was to be a foundation that other researchers could use," says CyLab's Kyle Crichton, a Ph.D. student in Engineering and Public Policy and the study's lead author. "Now that we know what normal behavior looks like, we can start to identify anomalous behavior and begin to address any number of security challenges."

To create their dataset, the authors of the study observed the browsing behavior of 257 willing participants through the Security Behavior Observatory (SBO), a group of participants consenting to have their daily computing behaviors observed. One might think consenting to being monitored may lead one to act a bit different than they normally would, but Crichton says he doesn't believe that happened here.

"In general, there was a substantial number of visits to potentially pirated streaming websites, pornographic websites, and gambling websites," Crichton says. "Therefore, we assume that they were generally behaving as they normally do."

So what does "normal" browsing look like? Lots of browser tab usage—some use just a few and some use a ton—and most time is spent on the top 1% of websites.

"People spend most of their time on a small number of websites," says Crichton. "Fifty percent of people's browsing time is spent on roughly 30 websites, among millions of websites."

Occasionally, Crichton says, people end up at what he refers to as "the periphery" of the Internet—relatively low traffic websites that are commonly associated with riskier content. These sites are often adware, gambling, pornography, and potentially illegal streaming websites.

"We observed a lot of people who started out at a popular streaming service like Netflix or Hulu, and they must not have found what they wanted, then they'd jump out to the periphery," Crichton says.

While the study may serve as a foundation for other researchers to use, it'll do so only until people's browsing behavior evolves enough to necessitate recording a new baseline, which Crichton says is inevitable.

"When Google came out in the late 90s, people's way of finding content quickly changed," he says. "People's browsing behavior shifted again when tabbed browsing was introduced in the mid-2000s. It's these game changers that are introduced, and things rapidly evolve.Misconceptions plague security and privacy tools

More information: Kyle Crichton et al, How Do Home Computer Users Browse the Web?, ACM Transactions on the Web (2021). DOI: 10.1145/3473343

Provided by Carnegie Mellon University

Action video games make players better learners of visual and memory tasks

by Chris Barncard, University of Wisconsin-Madison

Playing video games that are heavy on action can make you better at some new tasks. New research reveals that these games are helping by teaching players to be quicker learners.

"Imagine taking an American and putting them through physical training to boost their athleticism," says C. Shawn Green, a psychology professor at the University of Wisconsin-Madison who studies how people learn. "If you then have them try to play rugby for the first time ever, they might not look that good. After all, even a good athlete who is stepping into a rugby match for the first time will have to learn a lot of new rules. However, their increased athleticism will mean that they'll tend to be in slightly better positions initially than people with lesser athleticism, and thus will learn to play rugby more quickly."

That idea is similar for action video games—typically those in a genre called first-person shooters—in which players are rewarded for swiftly and accurately tracking and reacting to features of the game that appear and move quickly.

"If you're increasing the equivalent of athleticism for perceptual cognitive abilities—like visual attention or speed of processing—that should allow you to learn faster when you've got a new task that calls on those abilities," Green says.

The results will help researchers understand how gaming—which is used to train laparoscopic surgeons and drone pilots, and to help people with amblyopia (sometimes called "lazy eye") and attention deficit disorders—creates some of its well-documented positive effects.

"Games are really powerful, complex experiences," says Green, whose work is supported by the Office of Naval Research. "We know they produce interesting changes in behavior, but their level of complexity makes them hard to study."

The study also shows that not all training activities are equal. Some types of practice can make you perfect, but only at one thing. Types of training that make trainees better at quickly learning to perform a broad range of tasks—or at least more than one—have obvious advantages.

"If you have people who are new to a basketball court shoot nothing but free throws over and over and over, they'll probably get much better at shooting straight on from 15 feet," Green says. "But then if you have them shoot from somewhere else on the court, they're probably going to go right back to where they started. We call that a failure of transfer or a failure of generalization."

In a pair of xperiments described recently in the journal Communications Biology, 25 participants at the University of Rochester in New York and then 52 participants at the University of Geneva in Switzerland were separated into roughly equal groups assigned to play 45 hours of either action video games (such as those from the Call of Duty series) or other popular video games that unfold at a different pace without relying so much on visual attention and reaction speed (games such as Sims and Zoo Tycoon).

Before the players began their gaming assignments, they were tested with tasks that measured their visual perception and working memory skills. The visual perception tasks required participants to use a brief glance to pick out the direction of movement of an object or orientation of stripes running across a shape. The working memory tests were more challenging, asking players to listen and watch for pairs of letters read aloud and shapes appearing in different locations on a screen, and report when one matched a sound or placement from a certain number of turns back.

Both groups came out relatively even in the initial tests. But after their contrasting gaming experiences, the action game players were different.

"They had a slight advantage right away, after playing the action games. But the bigger effect was that they improved faster at these orientation and memory tasks than the people who played other games," says Green, who collaborated on the study with researchers from Rochester, Geneva, New York University and the University of California, Irvine.

The tests were chosen because the simple movements and orientation of basic shapes engage parts of the brain involved in very rudimentary visual processing and working memory. "Constantly having to manage new stuff versus old stuff as information comes in" is a common factor in tackling new tasks, Green says.

Teasing the significant aspects out of the complexity will help future game designers who are focused on training as much as—or more than—entertainment.

"There are issues with action games—they tend to be violent, for example, and it's unlikely that is necessary to cause the effects we want to see in players," Green says. "Before you can start designing games with the goal of maximizing the benefits, you need to know what's helping and what's not.

Playing action video games can boost learning, new study reports

More information: Ru-Yuan Zhang et al, Action video game play facilitates "learning to learn", Communications Biology (2021). DOI: 10.1038/s42003-021-02652-7

Journal information: Communications Biology

Provided by University of Wisconsin-Madison

Using overpasses as shelter from tornado?

by American Institute of Physics

Meteorologists and emergency workers continue to contest the popular thinking that waiting out a tornado under an overpass is safe. According to the National Weather Service, doing so could actually increase the risk of death, in part because the wind from a tornado is thought to accelerate as it flows under the overpass, in what's known as the wind tunnel effect.

However, few experimental studies show exactly how this acceleration takes place or if it takes place at all. In Physics of Fluids researchers from the University of Rhode Island found no evidence of such acceleration.

"In our research, there is no one finding that would suggest one should or should not use an overpass for protection from a tornado as a last-resort shelter area," co-author D.M.L. Meyer said.

The researchers examined the pressure, velocity, and force fields of tornado-strength winds surrounding an overpass. Experiments were performed in a standard wind tunnel using a scaled geometry of an overpass. A large fan was used to draw air through the tunnel at a top speed of about 130 miles per hour.

The researchers found no wind tunnel effect in their experiments.

"However, that doesn't mean the effect doesn't take place at all, just not in the locations we focused on," Meyer said. "More data and analyses are needed to determine how complex tornado-strength winds interact with the environment underneath an overpass, and our paper provides a start."

An overpass may be a dangerous place for shelter regardless. Wind may not decelerate, depending on the location, and flying debris may reach areas of the overpass that appear to be protected from the wind.

The researchers studied four locations: immediately above the overpass, immediately below it, between the I-beams, and the center of the travel lane under the overpass. Velocity and dynamic pressure measurements were obtained independently at each location as the overpass was rotated 0-90 degrees at 10-degree increments about its vertical axis. Lift and drag forces were also measured.

Wind tunneling can be explained using a garden hose. Water traveling through the hose flows at a constant flowrate, because the diameter is constant throughout the hose length. Place a thumb partially over the hose opening, and the flow constricts, accelerating the water due to the smaller cross-section. This causes the water to spurt further than without the thumb.

Hurricane straps keep roofs on houses and can improve safety during tornadoes

More information: D.M.L. Meyer et al, Tornado-strength winds interacting with a highway overpass, Physics of Fluids (2021). DOI: 10.1063/5.0065233

Journal information: Physics of Fluids

Provided by American Institute of Physics

Study shows medicinal cannabis products can help with depression and improve quality of life

by Bob Yirka , Medical Xpress

A team of researchers affiliated with multiple institutions in the U.S. has found evidence that medicinal cannabis products relieve depression and improve the quality of life. In their paper published in the journal Frontiers in Psychiatry, the group describes their study involving online surveys about the benefits of cannabis products.

Prior research findings regarding the use of cannabis-based products to treat depression and anxiety have been mixed. Some patients have shown improvements while others have not. Prior research has also found that other drugs developed to treat depression and anxiety also have mixed results—some have seen improvements while others have not, and some patients have found that they cannot tolerate the side effects of the drugs. Also, some people have begun using medicinally approved cannabis products to help with their depression, anxiety, chronic pain or sleep disorder, regardless of the research track record—either independently, or with assistance from a doctor. In this new effort, the researchers conducted a study to gauge the opinions of people who use such products, rather than focusing on reports from the medical community regarding how well they thought they worked.

The study was carried out over four years. At the onset, the researchers received responses from 368 people who reported using cannabis products to reduce their depression and/or anxiety, or to help them sleep. As a control group, they also received responses from 170 people who were not using cannabis products but who were considering doing so due to their problems with depression or anxiety.

The researchers found that those people taking cannabis products (mostly those containing CBD rather than THC) reported lower levels of depression than the control group, although they saw no difference in anxiety. They also found those taking cannabis products reported a higher quality of life and better sleep than the control group. The researchers also found reduced levels of depression later on in those who continued to take cannabis products and also in those who began using them during the study. And interestingly, they also found that those who began taking the products during the study also reported improvements in anxiety and quality of life.

Many adults with breast cancer use cannabis but don't tell their doctors

More information: Erin L. Martin et al, Antidepressant and Anxiolytic Effects of Medicinal Cannabis Use in an Observational Trial, Frontiers in Psychiatry (2021). DOI: 10.3389/fpsyt.2021.729800

What causes disease outbreaks?

by University of Georgia

Since 1974, contaminated water has been the most common driver of large-scale zoonotic infectious disease outbreaks, according to new research from the Center for the Ecology of Infectious Diseases (CEID) at the University of Georgia. The next two greatest drivers are unusual weather patterns and changes in the abundance of disease vectors such as mosquitos and ticks.

Zoonotic diseases occur when pathogens are transmitted from animals to humans—prominent recent outbreaks include Ebola hemorrhagic fever and COVID-19. However, most zoonotic disease outbreaks involve fewer than 100 cases and are quickly brought under control. So what factors drive large-scale outbreaks?

In a study published in the Philosophical Transactions of the Royal Society B: Biological Sciences, researchers investigated over 4,400 zoonotic infectious disease outbreaks. They identified the 100 largest in terms of numbers of human cases, all of which infected thousands to hundreds of thousands of people. From the full list they also selected 200 outbreaks at random to serve as "case controls." The majority of these control outbreaks included 43 or fewer cases. They then compared the characteristics of large-scale and control outbreaks, particularly how the primary causes of infection and disease spread varied between them.

Lead author Patrick Stephens, an associate research scientist with the Odum School of Ecology and CEID, said that this research is one of the first peer-reviewed studies to quantify the variation of infectious disease outbreak drivers across the globe.

"In the age of COVID-19, it is understandable that many people may not realize how many outbreaks of other infectious diseases are caused by complex, intertwined ecological and socioeconomic conditions," he said. "We know that factors like exposure to wild mammals, habitat disruption, international trade and travel and contact with contaminated food and water are important considerations. Our research was designed to understand what proportion of outbreaks various drivers contributed to. To our knowledge, this study is the first to do so for a global sample of outbreaks of many diseases."

Stephens worked with CEID researchers Nicole Gottdenker of the College of Veterinary Medicine and John Drake, Annakate Schatz and John Paul Schmidt of the Odum School to compile a list of contemporary zoonotic infectious diseases documented in peer reviewed scientific literature. They identified and scored 48 specific infectious disease drivers related to the large-scale and control outbreaks in ecological, environmental and socioeconomic categories.

Water contamination is a key driver of disease outbreaks

Both large-scale and control outbreaks were associated with water contamination, which was the most common driver of large outbreaks and the second most common driver of the smaller control outbreaks. Examples of these water-associated diseases include hepatitis E, typhoid and shigellosis (dysentery). The remaining drivers differed, however.

In addition to water contamination, large outbreaks were most often associated with unusual weather patterns, changes in the abundance of vectors—carriers of disease like mosquitos or ticks—and sewage management.

Large outbreaks were also much more likely to be caused by viral pathogens such as SARS coronavirus, influenza virus and Japanese encephalitis virus than were smaller outbreaks. The typical smaller outbreaks were associated with food contamination, local livestock production and human-animal contact. Finally, individual large outbreaks tended to be driven by a greater variety of factors than control outbreaks.

"There is still a lot of work to do to understand how large-scale infectious disease outbreaks can be avoided and controlled," Stephens said. "Perhaps two-thirds of future infectious disease outbreaks are expected to be caused by zoonotic pathogens, and the number of these diseases is growing worldwide. Our research is an extremely important first step to better understand global variation in the drivers of outbreaks."

CDC IDs outbreak trends tied to treated recreational water

More information: Patrick R. Stephens et al, Characteristics of the 100 largest modern zoonotic disease outbreaks, Philosophical Transactions of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rstb.2020.0535

Provided by University of Georgia

Sex, drugs, and genes: Moral attitudes share a genetic basis

by Association for Psychological Science

Few hallmarks of the 1960s counterculture stand out like sex, drugs, and rock-n-roll—elements of a "lifestyle" that Life magazine once branded as "antithetical in almost every respect to that of conventional America." Over the decades, as rock music became more mainstream, public condemnation of casual sex and illicit drugs endured. Why was that? Part of the answer may reside in our genes.

New research published in the journal Psychological Science suggests that there is a common genetic basis underlying a person's disapproval of noncommittal sex and their condemnation of recreational drug use. This research helps psychologists better understand how heredity may relate to some of our deeply held moral values.

"People adopt behaviors and attitudes, including certain moral views, that are advantageous to their own interests," said Annika Karinen, a researcher at Vrije Universiteit Amsterdam in the Netherlands and the lead author on the paper. "People tend to associate recreational drug use with noncommitted sex. As such, people who are heavily oriented toward high commitment in sexual relationships morally condemn recreational drugs, as they benefit from environments in which high sexual commitment is the norm."

Past studies have shown that openness to engage in noncommittal sex is partially explained by genes; the rest is explained by the unique environment not shared by siblings.Karinen and her colleagues wanted to study if moral views concerning drug use, which surveys have shown closely correlate with openness to noncommittal sex, were influenced by the same genetic factors.

To tease out hereditary from environmental factors, the researchers surveyed 8,118 Finnish fraternal and identical twins to examine how open they were to recreational drug use and to sex outside of a committed relationship. Participants answered questions that gaged their moral views of situations in which people used recreational drugs, such as at a party or with friends. The participants were also asked questions that evaluated their openness to noncommitted sex.

The researchers then compared fraternal and identical twin pairs to assess the extent to which condemnation of recreational drugs, openness to noncommittal sex, and the relationship between the two was explained by (a) genes, (b) the shared environment—such as growing up in the same household or community, or (c) unique experiences and environments not shared by the twins. The researchers found that moral views concerning both recreational drugs and openness to noncommitted sex are approximately 50% heritable, with the remaining 50% explained by the unique environment.

Furthermore, approximately 75% of the relationship between openness to noncommitted sex and moral views concerning recreational drugs was explained by genetic effects, and the remainder was explained by the unique environment. The researchers also found substantial overlap in the genetic effects underlying both factors—namely, that approximately 40% of the genes underlying openness to noncommitted sex also underlie moral views concerning recreational drugs.

"These findings suggest that the genetic effects that influence openness to noncommitted sex overlap with those that influence moral views concerning recreational drugs," said Karinen. "Important parts of hot-button culture-war issues flow from differences in lifestyle preferences between people, and those differences in lifestyle preferences appear to partly have a genetic basis."

Recreational ketamine use has increased in recent years, but remains rare

More information: Annika K. Karinen et al, Sex, Drugs, and Genes: Illuminating the Moral Condemnation of Recreational Drugs, Psychological Science (2021). DOI: 10.1177/0956797621997350

Journal information: Psychological Science

Provided by Association for Psychological Science

NO NEED FOR MILLION DOLLAR LOTTERIES

Even a $25 cash card can motivate some to get vaccinated

by Cara Murez

Can offering small cash cards, say for $25, be the difference between someone choosing to get their COVID-19 vaccine or waiting?

Yes, according to a study in North Carolina that offered $25 cash cards to people who got vaccines last spring at sites in four participating counties.

About 9% of those surveyed after getting their vaccines said that they would not have come to get vaccinated if it were not for the cash card. About 15% said they had waited to get a vaccine until they found an event with an incentive.

"We were really interested in North Carolina and at the Department of Health and Human Services to use multiple strategies to help North Carolinians get vaccinated as quickly and fairly as possible," said study author Dr. Charlene Wong. She is chief health policy officer for COVID-19 of the North Carolina Department of Health and Human Services.

"We actually planned the evaluation of this pilot incentive program from the very beginning because we knew that we wanted to better understand what was working, what we might want to modify, as we thought about scaling this program to other places in the state, as well as other strategies to increase vaccinations in North Carolina," Wong said.

Public health officials added a twist to the program: paying $25 to both the vaccine recipient and the person who drove them to the event, though not two $25 cards if people drove themselves.

Paying the driver may have reduced transportation barriers for some. It also may have encouraged the types of one-to-one conversations with people who are known and trusted by those who still needed to get vaccinated, Wong said.

"We were very intentional about doing that because we knew that for some individuals in North Carolina there were real transportation barriers to be able to get to a vaccine site," Wong said.

In designing its incentives and evaluation of their success, public health officials looked back at past behavioral science research, including incentives offered for other vaccinations and cancer screenings, Wong said.

Guaranteed incentives can offset costs, such as lost wages, transportation and child care, according to the study.

Different types of incentives may make a difference for individuals. Tickets to an amusement park may have been influential for people with kids, for example, Wong said.

In particular, these small incentives helped address cost barriers to vaccinations for historically marginalized populations, including those who are lower income, Hispanic and Black, Wong noted.

"We were so pleased to see that. And that was why, that was certainly part of the reason that we wanted to do these surveys so that we could actually really look down to that level of equity so that we could better understand for whom was this important and was it really helping to address some of these barriers," Wong said.

The program distributed 2,890 cash cards to vaccine recipients and another 1,374 to drivers. The incentive program offered different amounts of money at times. The researchers found the rate of decline in vaccine uptake, at a time when numbers were declining across the country, was halved in places that had these incentives.

The findings were published online Oct. 25 in JAMA Internal Medicine.

Now, in North Carolina, about 71% of adults have received at least one dose of one of the three approved COVID-19 vaccines. In the United States, about 77.4% of eligible ages (12 and up) had received at least one dose of the vaccine by Oct. 21 and about 66.9% were fully vaccinated, according to the U.S. Centers for Disease Control and Prevention.

Mitch Rothholz, chief of staff for the American Pharmacists Association, which was not involved in this study, wondered if the incentive for drivers may have made the difference in vaccine uptake in the North Carolina program.

Sometimes, incentives have backfired because people have been suspicious of their intent, Rothholz said.

"I think every individual has different perspectives that's going to motivate them to get vaccinated. We found it's really an individual decision," Rothholz said. "In the work we've done on vaccine confidence, a lot of it has also been the relationship and the discussions that they've had with other individuals that they respect in their community, like their pharmacist."

It can take several interactions—while listening, providing information and being nonjudgmental—for someone to decide to get vaccinated, Rothholz said.

In its research profiling who was still unvaccinated in late May, the Kaiser Family Foundation (KFF) determined that unvaccinated adults were younger, less educated, more likely to be Republican, people of color and those who did not have health insurance.

The key demographic differences between the "definitely not" and "wait-and-see" groups were racial and ethnic identity and political partisanship, according to the foundation, with the definitely nots having a larger number of people who were white and considered themselves to be Republican and the waiting group being more diverse, with about half of all those included being people of color.

By September, KFF found that more than seven in 10 adults reported being at least partially vaccinated, across racial and ethnic groups. It continued to find large gaps in vaccine use by partisanship, education level, age and health insurance status.

Various incentives, including time off work to recover from a vaccine or paid transportation, were effective in moving the wait-and-see group, said Ashley Kirzinger, associate director of public opinion and survey research at KFF. She also noted that these programs do seem to have helped with vaccine equity.

"I think it's important to realize that these kind of incentive programs can move the needle, especially in populations that are more open to getting a vaccine but are facing access issues, but we haven't found any evidence that it's going to persuade the most resistant populations," Kirzinger added.

Mortality study reinforces safety of COVID-19 vaccinations

More information: The U.S. Centers for Disease Control and Prevention has more on COVID-19 vaccines.

Charlene A. Wong et al, Guaranteed Financial Incentives for COVID-19 Vaccination, JAMA Internal Medicine (2021). DOI: 10.1001/jamainternmed.2021.6170

Journal information: JAMA Internal Medicine

Green tea catechins promote oxidative stress

by Peter Rüegg, ETH Zurich

Green tea is seen as healthy and promotes a longer life, supposedly due to its high level of antioxidants. Researchers at ETH Zurich have now cast doubt on previous assumptions about how these ingredients work.

Green tea has long been known to have health benefits. In particular, it contains catechins called ECG and EGCG that are said to prolong life. These two substances belong to the group of polyphenols. They are considered antioxidants, which means they counteract or prevent oxidative stress in the body caused by aggressive free radicals of oxygen.

Until now, research has assumed that the catechins neutralize these free radicals and thus prevent damage to cells or DNA. One source of oxygen free radicals is metabolism; for example, when the mitochondria—the powerhouses of the cell—are working to produce energy.

ETH researchers led by Michael Ristow, Professor of Energy Metabolism at the Department of Health Sciences and Technology at ETH Zurich, together with colleagues from the University of Jena, have now taken a closer look at how catechins act in the nematode worm C. elegans. And they have come to a different, seemingly paradoxical conclusion: Rather than suppressing oxidative stress, the catechins in green tea promote it.

Temporary increase in oxidative stress

In a study just published in the journal Aging, Ristow's team shows that these polyphenols from green tea initially increase oxidative stress in the short term, but that this has the subsequent effect of increasing the defensive capabilities of the cells and the organism. As a result, the catechins in green tea led to longer life and greater fitness in nematodes that were fed them.

"That means green tea polyphenols, or catechins, aren't, in fact, antioxidants, but rather pro-oxidants that improve the organism's ability to defend itself, similar to a vaccination," explains study leader Ristow.

However, this increase in defensive capability manifests not through the immune system, but rather by activating genes that produce certain enzymes such as superoxide dismutase (SOD) and catalase (CTL). It is these enzymes that inactivate the free radicals in the nematode; they are essentially endogenous antioxidants.

Sport and calorie reduction have a similar effect

Ristow isn't surprised to see this kind of mechanism at work. His research group showed back in 2009 that the reason sport promotes health is because sporting activities increase oxidative stress in the short term, thus improving the body's defenses. Consuming fewer calories has the same effect, as has been shown several times in animals. Mice fed a reduced-calorie diet live longer than those fed a normal, high-calorie diet. "So it made sense to me that the catechins in green tea would work in a similar way," Ristow explains.

He goes on to say that the findings from this study translate well to humans. The basic biochemical processes by which organisms neutralize oxygen free radicals are conserved in evolutionary history and are present in everything from unicellular yeast to humans.

Green tea yes, concentrates no

Ristow himself drinks green tea every day, a practice he recommends. But he advises against taking green tea extracts or concentrates. "At a certain concentration, it becomes toxic," he says. High-dose catechins inhibit mitochondria to such an extent that cell death ensues, which can be particularly dangerous in the liver. Anyone consuming these polyphenols in excessive doses risks damaging their organs.

While the most catechins are to be found in Japanese varieties of green tea, other green teas also contain sufficient amounts of these polyphenols. Black tea, on the other hand, contains a much lower level of catechins, since these are largely destroyed by the fermentation process. "That's why green tea is preferable to black tea," Ristow says.

Is green tea a fad or a real health boost?

More information: Jing Tian et al, Green tea catechins EGCG and ECG enhance the fitness and lifespan of Caenorhabditis elegans by complex I inhibition, Aging (2021). DOI: 10.18632/aging.203597

Provided by ETH Zurich

New study finds black spruce trees struggling to regenerate amid more frequent arctic fires

The resulting ecological shift could have rippling impacts on the boreal region, including acceleration of permafrost thaw and loss of biodiversity.

Peer-Reviewed Publication

WOODWELL CLIMATE RESEARCH CENTER

A new study, published in the Proceedings of the National Academy of Sciences (PNAS), finds that black spruce trees — a key species on the boreal landscape for millennia — are losing their resilience and capacity to regenerate in the face of warming temperatures and increasingly frequent Arctic wildfires. A continuation of this trend could result in a landscape-wide ecological shift that would have a complex and rippling impact on the region, including an acceleration in permafrost thaw, and a loss of valuable biodiversity.

In boreal North America, the thick, spongy soils on which black spruce grows are made of peat moss and lichens that retain moisture very well but when they do dry out are highly flammable. Black spruce rely on fires for regeneration — their cones open up in the heat and drop seeds onto the charred organic soil — but this latest study indicates that more severe fires that burn deeper into these peat soils are leading to a short-circuit of the regeneration process.

In synthesizing data from more than 1500 fire-disturbed sites, researchers found that black spruce’s ability to regenerate after fire dropped at 38% of sites and failed completely 18% of the time — numbers never before seen in a species evolved to thrive after fire. Significant shifts in wildfire regimes are pushing black spruce forests to a tipping point, beyond which the iconic species may lose its place as the dominant tree species in boreal North America.

“This trend is especially alarming given its potential impact on Arctic carbon storage,” said Dr. Brendan Rogers, Associate Scientist at Woodwell Climate Research Center and study co-author. “In many parts of the boreal region, the mossy soil layers that promote black spruce regeneration also insulate permafrost. As fires increase and these forests dry out, however, loss of black spruce forests could accelerate permafrost thaw and trigger a warming feedback loop, pushing black spruce to its tipping point and facilitating the release of massive amounts of carbon from the permafrost into the atmosphere.”

Widespread loss of black spruce also has implications for biodiversity, particularly caribou species that overwinter in the forest and feed on lichen. Both barren-ground and boreal caribou, important cultural species for northern communities, are already in decline across the continent and would suffer more losses if the ecosystem shifts away from the black spruce-lichen forests that provide food and refuge.

“Basically, as the climate warms, rising Arctic temperatures are causing black spruce forests to dry out, and the drier the system is, the more vulnerable it is to fire,” said Dr. Jennifer Baltzer, Canada Research Chair in Forests and Global Change at Wilfrid Laurier University and study lead. “As climate change continues to push these systems to an ever drier state, these tipping points are more likely to be reached, with devastating impacts on the boreal biome and the rest of the world.”

About Woodwell Climate Research Center:

Woodwell Climate Research Center is an organization of renowned researchers who work with a worldwide network of partners to understand and combat climate change. We bring together hands-on experience and 35 years of policy impact to develop societal-scale solutions that can be put into immediate action. Our Falmouth, MA headquarters are located on the traditional and sacred land of the Wampanoag people who still occupy this land, and whose history, language, traditional ways of life, and culture continue to influence this vibrant community. Woodwell Climate has earned Charity Navigator’s highest rating of 4 stars, as well as a Gold Seal of Transparency from GuideStar.

JOURNAL

Proceedings of the National Academy of Sciences

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Increasing fire and the decline of fire adapted black spruce in the boreal forest

ARTICLE PUBLICATION DATE

25-Oct-2021

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