Marmosets practise calling their mother in the womb

A study shows that newborn marmosets’ earliest vocalisations to call for their parents begin in the womb, with findings that may also apply to humans

Peer-Reviewed Publication

ELIFE

 

IMAGE: STILLS OF A MARMOSET FETUS AND INFANT view more 

CREDIT: GHAZANFAR LAB, PRINCETON UNIVERSITY (CC BY 4.0)

Baby marmosets begin practising the face and mouth movements necessary to call their family  for help before they are born, shows a study published today in eLife.

This finding may also apply to humans, as ultrasounds in the third trimester of pregnancy have shown developing humans in the womb making crying-like movements.

The first cries and coos of humans and other primates are essential to their survival. In addition to allowing them to call their family members for help, these vocalisations and interactions with their parents and other caregivers lay the groundwork for more complex communication later in life.

“We wanted to know how those very first neonatal vocalisations develop,” says lead author Darshana Narayanan, who conducted the study as a graduate student at the Department of Psychology and the Princeton Neuroscience Institute, Princeton University, New Jersey, US.

Narayanan and colleagues conducted ultrasounds two to three times per week in four pregnant marmosets for a total of 14–17 ultrasound sessions per marmoset, starting when the face first became visible on ultrasound and ending the day before birth. The team used the ultrasound scans to longitudinally track the head, face and mouth movements of the developing marmosets and compared them with the newborn marmosets’ movements when they called out.

Using frame-by-frame analysis, the team found that the developing marmosets’ head and mouth movements coordinated initially, but the mouth movement became distinct over time. Eventually, they became almost indistinguishable from movements made by crying newborn marmosets briefly separated from their mothers within the first 24 hours after birth. 

To verify that these movements were not generic head and mouth movements, the team also compared pre and postnatal licking movements and movements associated with another marmoset vocalisation called a “twitter”. Their results showed that the pattern of crying movements before and following birth was distinct from the licking or twitter movements.

“Our experiments show that marmosets begin practising the movements needed for important social calls even before they can generate a sound,” Narayanan says. She adds that studying these movements further in marmosets may help scientists learn more about the development of social vocalisations in other primates, including humans.

“Marmoset monkeys offer a special opportunity to study primate vocal development,” concludes senior author Asif Ghazanfar, Professor at the Princeton Neuroscience Institute, Princeton University. “Like humans, marmosets are very social and learn to vocalise through interactions with their parents.”

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About eLife

eLife transforms research communication to create a future where a diverse, global community of scientists and researchers produces open and trusted results for the benefit of all. Independent, not-for-profit and supported by funders, we improve the way science is practised and shared. From the research we publish, to the tools we build, to the people we work with, we’ve earned a reputation for quality, integrity and the flexibility to bring about real change. eLife receives financial support and strategic guidance from the Howard Hughes Medical Institute, Knut and Alice Wallenberg Foundation, the Max Planck Society and Wellcome. Learn more at https://elifesciences.org/about.

To read the latest Neuroscience research published in eLife, visit https://elifesciences.org/subjects/neuroscience.

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JOURNAL

eLife

DOI

10.7554/eLife.78485 

ARTICLE TITLE

Prenatal development of neonatal vocalizations

ARTICLE PUBLICATION DATE

26-Jul-2022

Researchers confirm brain region’s role in mind-body communication

Findings could advance treatment for Parkinson’s disease

Peer-Reviewed Publication

UNIVERSITY OF IOWA

University of Iowa researchers have confirmed in a new study that a specific region in the brain is critical to governing the mind’s communication with the body’s motor control system. The findings could yield advances in treatment for Parkinson’s disease, as declining motor coordination is a central symptom of the disorder.

In experiments with humans, the researchers pinpointed the subthalamic nucleus as the region in the brain that communicates with the motor system to help the body stop an action. This communication is vital because it helps humans avoid surprises and react to potentially dangerous or unforeseen circumstances.

The subthalamic nucleus is a tiny grouping of cells that is part of the basal ganglia, which is a key circuit in controlling movement. The basal ganglia takes initial motor commands generated in the brain and either amplify or halt specific parts of those commands as they pass from the central nervous system to the spinal cord.

“You can think of the subthalamic nucleus as the core region in this ‘halting’ of extra, unwanted components of compound movements, as it is the last relay station before the output nuclei of the basal ganglia, which then communicates these commands to the wider motor system,” says Jan Wessel, associate professor in the Department of Psychological and Brain Sciences at Iowa and the corresponding author on the study.

Previous research had indicated the subthalamic nucleus’ role in this stage of brain-motor control communication, but the hypothesis had not been directly tested in humans until now. To do that, the researchers used some ingenious techniques. First, they recruited 20 patients who have Parkinson’s disease, which affects motor control. These patients had implanted deep-brain stimulators, which the researchers used to activate or deactivate the subthalamic nucleus. They then tracked those changes to motor-control activity through a simple stop-action task, monitoring the brain-motor control responses through a technique called transcranial magnetic stimulation.

Parkinson’s disease patients are treated regularly with deep-brain stimulation, but the addition of transcranial magnetic stimulation allowed the researchers to confirm the subthalamic nucleus’ definitive role. Wessel partnered on the experiments with Jeremy Greenlee, professor and the Arnold H. Menezes Chair in the Department of Neurosurgery, who cares for patients with Parkinson’s disease.

“Deep-brain stimulation is the only method to causally and systematically influence the activity of deeply embedded brain nuclei like the subthalamic nucleus in awake, behaving humans,” says Wessel, also an associate professor in the Department of Neurology. “However, combining deep-brain stimulation with transcranial magnetic stimulation is a highly complicated and novel technical endeavor, especially in awake, behaving humans.”

The subthalamic nucleus–motor control link is important, Wessel says, because it puts to rest a central question in the brain’s communication with the body’s motor system, especially how an initiated action is suddenly halted. But it has potential benefits to patients, too.

“The subthalamic nucleus is a key therapeutic target in Parkinson’s disease,” Wessel says. “Indeed, just like it was done for the patient sample in our study, implantation of stimulation electrodes into the subthalamic nucleus is a highly successful treatment option for the motoric symptoms of Parkinson’s disease. Our study provides some mechanistic insights into this potential patient-care benefit.”

The study, “A causal role for the human subthalamic nucleus in non-selective cortico-motor inhibition,” was published online July 15 in the journal Current Biology.

Contributing authors, all from Iowa, include Darcy Diesburg and Nathan Chalkley.

The National Institutes of Health and the U.S. National Science Foundation funded the research.

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JOURNAL

Current Biology

DOI

10.1016/j.cub.2022.06.067 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

A causal role for the human subthalamic nucleus in non-selective cortico-motor inhibition

Enthusiasm for green energy varies, and few are willing to pay more for it

New green energy survey reveals Americans generally fall into four categories: Evangelists, Promoters, Passives or Detractors; more than half say the long-term benefits of green energy outweigh the cost, but only one-third are willing to pay more

Reports and Proceedings

STEVENS INSTITUTE OF TECHNOLOGY

Whether they identify as Evangelists, Promoters, Passives or Detractors of green energy, few Americans are willing to pay more to adopt green energy, according to the Stevens TechPulse Report: Green Energy Perceptions and Usage. The national poll, conducted in June 2022, surveyed 2,210 adults on behalf of Stevens Institute of Technology by Morning Consult and examined Americans’ views on a wide range of green energy-related issues.

“Green energy is at the heart of America’s energy transition,” said Philip Odonkor, an assistant professor in the School of Systems and Enterprises at Stevens. “This survey highlights the tremendous progress made in sparking public interest, but also exposes the bigger challenge that lies ahead — converting that momentum into tangible action.”  

Green Energy Adoption Varies from Evangelists to Detractors

Based on the survey, there is no national consensus on green energy adoption. Generally, responses aligned with one of four categories in a spectrum of very likely to very unlikely to seek out green energy technologies for personal use. Self-reported data describe the demographics most closely associated with each category.

Evangelists (26%)
Very likely to seek out green energy technologies for personal use
Evangelists skew male, younger, most likely to be urban, most educated

Promoters (30%)
Somewhat likely to seek out green energy technologies for personal use
Promoters skew female, urban/suburban, college educated

Passives (27%)
Neutral on seeking out green energy technologies for personal use
Passives skew female, slightly older, suburban/rural, less educated

Detractors (10%)
Unlikely to seek out green energy technologies for personal use
Detractors skew male, most likely to be older and rural, least educated

 Don’t know/no opinion (7%)

Price Is Top of Mind

The essential question is whether and how much people will pay more to use green energy. More than half of adults (52%) say the long-term benefits of green energy outweigh the cost, but only one-third (36%) say they’re willing to pay more for green energy. And when it comes to how much more, adults overall say they would be willing to pay 10% more per month for green energy related consumption. Among Evangelists, this rose to 19%, with Promoters at 12%, Passives at 9% and Detractors at 1%.

When weighing factors about whether to purchase green energy-related products (e.g., solar panels), adults view price (86%) as the most important aspect, although function/performance (82%) and ease of maintenance (83%) are also important overall. When actually making a green energy-related product purchase, more than six in 10 (63%) say price is their primary consideration, and that environmental impact is secondary to price.

Importance of Higher Education in Preparing Students for Green Careers

Green careers, as defined by the U.S. Department of Labor, are “any occupation that is affected by activities such as conserving energy, development alternative energy, reducing pollution, or recycling.” When asked how important it is, if at all, for universities/colleges to offer education that prepares students for green careers, three in four adults (73%) say it’s important versus only 4% who say it’s not important. Nearly all Evangelists (97%) say it’s important, closely followed by 90% of Promoters with a solid majority of Passives (60%), and 36% of Detractors.

“This survey illustrates the challenges our society faces in building consensus around policies, funding models and increasing adoption of sustainable energy solutions for the future,” said Nariman Farvardin, president of Stevens Institute of Technology. “It is also abundantly clear that universities such as Stevens Institute of Technology must play a critical role in increasing public awareness, educating the future energy workforce and contributing its R&D capacity to advance the field.”

Responsibility for Green Energy Adoption in Everyday Life

When it comes to the future of green energy, half of all adults (48%) view larger entities, such as

governments and businesses, as well as individuals and households as equally responsible for adopting its use in everyday life.

Fuzziness on Terminology

There is a lack of clarity among Americans on exactly what green energy is. The majority of adults (48%) say they are most familiar with the term renewable energy, while 35% say clean energy and only 16% say green energy technology. There is overlap among phrases used by survey participants with “solar and wind” noted for all three and “electric vehicles” being examples for clean and green energy technology.

“Green energy has an identity problem,” said Odonkor, an expert in sustainable energy and energy optimization. “The rich diversity of overlapping terms — from clean energy, to sustainable and renewable energy — reflects and reinforces confusion in public understanding.”

This survey is the second in the Stevens TechPulse Report series conducted by Morning Consult on behalf of Stevens Institute of Technology to elucidate public understanding, acceptance and concerns about emerging technology, and its impact on humanity and society.

Learn more about this survey and Stevens TechPulse Report: stevens.edu/news/stevens-techpulse-report

Methodology

This poll was conducted on behalf of Stevens Institute of Technology by Morning Consult between June 11-June 12, 2022 among a sample of 2,210 adults. The interviews were conducted online, and the data were weighted to approximate a target sample of adults based on gender, educational attainment, age, race, and region. Results from the full survey have a margin of error of +/- 2%.

– Stevens –

About Stevens Institute of Technology

Stevens Institute of Technology is a premier, private research university situated in Hoboken, New Jersey. Since our founding in 1870, technological innovation has been the hallmark of Stevens’ education and research. Within the university’s three schools and one college, 8,000 undergraduate and graduate students collaborate closely with faculty in an interdisciplinary, student-centric, entrepreneurial environment. Academic and research programs spanning business, computing, engineering, the arts and other disciplines actively advance the frontiers of science and leverage technology to confront our most pressing global challenges. The university continues to be consistently ranked among the nation’s leaders in career services, post-graduation salaries of alumni, and return on tuition investment.

Study: One in five adults don’t want children — and they’re deciding early in life

Peer-Reviewed Publication

MICHIGAN STATE UNIVERSITY

EAST LANSING, Mich. – The U.S. Supreme Court’s overturning of Roe v. Wade paved the way for limits on abortion but also created uncertainty around the future of birth control. This could have far-reaching implications for many people as a research team from Michigan State University found over one in five Michigan adults do not want children.

“We found that 21.6% of adults, or about 1.7 million people, in Michigan do not want children and therefore are ‘childfree.’ That’s more than the population of Michigan’s nine largest cities,” said Zachary Neal, associate professor in MSU’s psychology department and co-author of the study. 

The study — published in Scientific Reports — used a set of three questions to identify childfree individuals separately from parents and other types of nonparents. The researchers used data from a representative sample of 1,500 adults who completed MSU’s State of the State Survey, conducted by the university’s Institute for Public Policy and Social Research. Because different types of nonparents are impossible to distinguish in official statistics, Neal explained that this study is one of the first to specifically count childfree adults.

“People — especially women — who say they don’t want children are often told they’ll change their mind, but the study found otherwise,” said Jennifer Watling Neal, associate professor in the psychology department at MSU and co-author of the study. “People are making the decision to be childfree early in life, most often in their teens and twenties. And, it’s not just young people claiming they don’t want children. Women who decided in their teens to be childfree are now, on average, nearly 40 and still do not have children.”

The study was conducted in Michigan, but according to the 2021 census, Michigan is demographically similar to the United States as a whole. Because of this, Neal said, if the pattern holds up nationally, it would mean 50 to 60 million Americans are childfree.

“Following the U.S. Supreme Court’s overturning of Roe v. Wade, a large number of Americans are now at risk of being forced to have children despite not wanting them,” said Watling Neal. If further precedents are overturned and birth control becomes harder to access, many young women who have decided to be childfree may also have difficulty avoiding pregnancy.

Because so many people are childfree, the researchers said this group warrants more attention. They hope future work will expand beyond Michigan and will help the public understand both why people decide to be childfree and the consequences they experience from that decision.

(Note for media: Please include the following link to the study in all online media coverage: https://doi.org/10.1038/s41598-022-15728-z)

Contact: Kaylie Crowe, University Communications: (563)451-3976 crowekay@msu.edu; Kim Ward, University Communications: (517) 432-0117, kward@msu.edu  

Michigan State University has been advancing the common good with uncommon will for more than 165 years. One of the world’s leading research universities, MSU pushes the boundaries of discovery to make a better, safer, healthier world for all while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges.

For MSU news on the Web, go to MSUToday. Follow MSU News on Twitter at twitter.com/MSUnews.

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DOI

10.1038/s41598-022-15728-z 

Exposure to ‘forever chemicals’ costs US billions in health costs

Peer-Reviewed Publication

NYU LANGONE HEALTH / NYU GROSSMAN SCHOOL OF MEDICINE

Daily exposure to a class of chemicals used in the production of many household items may lead to cancer, thyroid disease, and childhood obesity, a new study shows. The resulting economic burden is estimated to cost Americans a minimum of $5.5 billion and as much as $63 billion over the lifetime of the current population.

The new work revolves around per- and polyfluoroalkyl substances (PFAS), a group of over 4,700 manmade chemicals that experts have detected for decades in the blood of millions of people. The chemicals are used, for example, in the production of water- and oil-resistant clothing, electronics, and nonstick cookware, and people are thought to ingest them as food comes into contact with packaging. The substances are believed to disrupt the function of hormones, signaling compounds that influence many bodily processes.

Led by researchers at NYU Grossman School of Medicine, the new study in roughly 5,000 Americans identified 13 medical conditions that may result from PFAS exposure, such as infertility, diabetes, and endometriosis, a painful disorder of the uterus. Together, the diseases generate medical bills and reduce worker productivity across a lifetime to create the costs measured by the study, say the study authors.

“Our findings add to the substantial and still-mounting body of evidence suggesting that exposure to PFAS is harming our health and undermining the economy,” says study co-author Linda Kahn, PhD, MPH, an assistant professor in the Departments of Pediatrics and Population Health at NYU Langone Health.

Previous investigations have quantified the medical burden and financial costs of low birth weight due to PFAS exposure. However, the new study, publishing online July 26 in the journal Exposure and Health, incorporates a much broader range of health consequences across the lifespan, says Kahn.

For the investigation, the researchers determined how many Americans were likely exposed to PFAS chemicals in 2018 using blood samples obtained from adults and children who participated in the U.S. National Health and Nutrition Examination Survey. Next, the study team analyzed data from dozens of studies in the past decade that explored diseases connected to the substances.

The research team used models from earlier investigations to estimate the national economic cost of the medical bills and lost worker productivity that resulted from the top five medical conditions that had the strongest links to PFAS exposure. These included low birth weight, childhood obesity, kidney and testicular cancers, and hypothyroidism.

Among the findings, the investigation revealed that childhood obesity was the largest contributor to the overall economic toll of PFAS exposure, costing about $2.7 billion. Hypothyroidism in women, a condition in which the thyroid cannot release enough hormones into the bloodstream, was the next highest contributor at $1.26 billion.

The study investigators also expanded the scope of their economic estimates to include eight other conditions with preliminary links to PFAS exposure, including endometriosis, obesity in adults, and pneumonia in children. When such diseases were considered, the total costs reached as high as $63 billion.

“Our results strongly support the recent decision by the Environmental Protection Agency to lower the safe allowable level of these substances in water,” says study senior author Leonardo Trasande, MD, MPP. “Based on our estimates, the cost of eradicating contamination and replacing this class of chemical with safer alternatives is ultimately justified when considering the tremendous economic and medical risks of allowing them to persist in the environment.”

Trasande, the Jim G. Hendrick MD Professor in the Department of Pediatrics at NYU Langone, cautions that despite the vast research on the health risks of PFAS, few studies have explored the effects of this exposure over time.

The research team next plans to examine the long-term risks of PFAS, adds Trasande, who also serves as director of NYU Langone’s Center for the Investigation of Environmental Hazards. In addition, the study authors plan to estimate the economic burden of other endocrine-disrupting contaminants, such as bisphenols, substances used in many plastics and can linings, fire retardants, and pesticides. Trasande is also a professor in NYU Langone’s Department of Population Health.        

Funding for the study was provided by National Institutes of Environmental Health Sciences grants P30ES000260, P2CES033423, and K99/R00ES030403.

Trasande has received financial support from Houghton Mifflin Harcourt, Audible, Paidos, and Kobunsha, as well as travel support from the Endocrine Society, the World Health Organization, United Nations Environment Programme, Japan Environment and Health Ministries, and the American Academy of Pediatrics. He also serves on scientific advisory boards for Beautycounter, IS-Global, and Footprint. The terms and conditions of these arrangements are being managed in accordance with the policies of NYU Langone Health.

In addition to Kahn and Trasande, Vladislav Obsekov, MD, at the Children's Hospital of Philadelphia, served as the study’s first author.

 

Media Inquiries:

Shira Polan

Phone: 212-404-4279

shira.polan@nyulangone.org

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JOURNAL

Exposure and Health

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Exposure to ‘Forever Chemicals’ Costs U.S. Billions in Health Costs

ARTICLE PUBLICATION DATE

26-Jul-2022

COI STATEMENT

Trasande has received financial support from Houghton Mifflin Harcourt, Audible, Paidos, and Kobunsha, as well as travel support from the Endocrine Society, the World Health Organization, United Nations Environment Programme, Japan Environment and Health Ministries, and the American Academy of Pediatrics. He also serves on scientific advisory boards for Beautycounter, IS-Global, and Footprint. The terms and conditions of these arrangements are being managed in accordance with the policies of NYU Langone Health.

Natural clean-up: Bacteria can remove plastic pollution from lakes

Peer-Reviewed Publication

UNIVERSITY OF CAMBRIDGE

 

IMAGE: A FRESHWATER LAKE IN NORWAY, ONE OF 29 EUROPEAN LAKES THAT WERE PART OF THE STUDY. view more 

CREDIT: SAMUEL WOODMAN

A study of 29 European lakes has found that some naturally-occurring lake bacteria grow faster and more efficiently on the remains of plastic bags than on natural matter like leaves and twigs.

The bacteria break down the carbon compounds in plastic to use as food for their growth.

The scientists say that enriching waters with particular species of bacteria could be a natural way to remove plastic pollution from the environment.

The effect is pronounced: the rate of bacterial growth more than doubled when plastic pollution raised the overall carbon level in lake water by just 4%.

The results suggest that the plastic pollution in lakes is ‘priming’ the bacteria for rapid growth –  the bacteria are not only breaking down the plastic but are then more able to break down other natural carbon compounds in the lake.

Lake bacteria were found to favour plastic-derived carbon compounds over natural ones. The researchers think this is because the carbon compounds from plastics are easier for the bacteria to break down and use as food.

The scientists caution that this does not condone ongoing plastic pollution. Some of the compounds within plastics can have toxic effects on the environment, particularly at high concentrations.

The findings are published today in the journal Nature Communications.

“It’s almost like the plastic pollution is getting the bacteria’s appetite going. The bacteria use the plastic as food first, because it’s easy to break down, and then they’re more able to break down some of the more difficult food – the natural organic matter in the lake,” said Dr Andrew Tanentzap in the University of Cambridge’s Department of Plant Sciences, senior author of the paper.

He added: “This suggests that plastic pollution is stimulating the whole food web in lakes, because more bacteria means more food for the bigger organisms like ducks and fish.”

The effect varied depending on the diversity of bacterial species present in the lake water – lakes with more different species were better at breaking down plastic pollution.

CAPTION

A freshwater lake in Norway, one of the 29 European lakes analysed as part of the study.

CREDIT

Andrew Tanentzap

A study published by the authors last year found that European lakes are potential hotspots of microplastic pollution.

When plastics break down they release simple carbon compounds. The researchers found that these are chemically distinct to the carbon compounds released as organic matter like leaves and twigs break down.

The carbon compounds from plastics were shown to be derived from additives unique to plastic products, including adhesives and softeners.

The new study also found that bacteria removed more plastic pollution in lakes that had fewer unique natural carbon compounds. This is because the bacteria in the lake water had fewer other food sources.

The results will help to prioritise lakes where pollution control is most urgent. If a lake has a lot of plastic pollution, but low bacterial diversity and a lot of different natural organic compounds, then its ecosystem will be more vulnerable to damage.

“Unfortunately, plastics will pollute our environment for decades. On the positive side, our study helps to identify microbes that could be harnessed to help break down plastic waste and better manage environmental pollution," said Professor David Aldridge in the University of Cambridge’s Department of Zoology, who was involved in the study.

The study involved sampling 29 lakes across Scandinavia between August and September 2019. To assess a range of conditions, these lakes differed in latitude, depth, area, average surface temperature and diversity of dissolved carbon-based molecules.

The scientists cut up plastic bags from four major UK shopping chains, and shook these in water until their carbon compounds were released.

At each lake, glass bottles were filled with lake water. A small amount of the ‘plastic water’ was added to half of these, to represent the amount of carbon leached from plastics into the environment, and the same amount of distilled water was added to the others. After 72 hours in the dark, bacterial activity was measured in each of the bottles.

The study measured bacterial growth - by increase in mass, and the efficiency of bacterial growth - by the amount of carbon-dioxide released in the process of growing.

In the water with plastic-derived carbon compounds, the bacteria had doubled in mass very efficiently. Around 50% of this carbon was incorporated into the bacteria in 72 hours.

"Our study shows that when carrier bags enter lakes and rivers they can have dramatic and unexpected impacts on the entire ecosystem. Hopefully our results will encourage people to be even more careful about how they dispose of plastic waste," said Eleanor Sheridan in the University of Cambridge’s Department of Plant Sciences, first author of the study who undertook the work as part of a final-year undergraduate project.

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JOURNAL

Nature Communications

DOI

10.1038/s41467-022-31691-9 

METHOD OF RESEARCH

Observational study

ARTICLE TITLE

Plastic pollution fosters more microbial growth in lakes than natural organic matter

ARTICLE PUBLICATION DATE

26-Jul-2022

Space study offers clearest understanding yet of the life cycle of supermassive black holes

Research uses X-ray telescopes and a new data analysis technique to describe space objects

Peer-Reviewed Publication

DARTMOUTH COLLEGE

 

IMAGE: THE DOUGHNUT-SHAPED RING SURROUNDING MANY SUPERMASSIVE BLACK HOLES TELLS RESEARCHERS ABOUT HOW FAST THE SPACE OBJECT IS FEEDING AND CAN CHANGE HOW THE BLACK HOLE IS VIEWED FROM EARTH. view more 

CREDIT: ESA/NASA, THE AVO PROJECT AND PAOLO PADOVANI

Black holes with varying light signatures but that were thought to be the same objects being viewed from different angles are actually in different stages of the life cycle, according to a study led by Dartmouth researchers.

The research on black holes known as “active galactic nuclei,” or AGNs, says that it definitively shows the need to revise the widely used “unified model of AGN” that characterizes supermassive black holes as all having the same properties.

The study, published in The Astrophysical Journal, provides answers to a nagging space mystery and should allow researchers to create more precise models about the evolution of the universe and how black holes develop.

“These objects have mystified researchers for over a half-century,” said Tonima Tasnim Ananna, a postdoctoral research associate at Dartmouth and lead author of the paper. “Over time, we’ve made many assumptions about the physics of these objects. Now we know that the properties of obscured black holes are significantly different from the properties of AGNs that are not as heavily hidden.”

Supermassive black holes are believed to reside at the center of nearly all large galaxies, including the Milky Way. The objects devour galactic gas, dust and stars, and they can become heavier than small galaxies.

For decades, researchers have been interested in the light signatures of active galactic nuclei, a type of supermassive black hole that is “accreting,” or in a rapid growth stage.

Beginning in the late 1980s, astronomers realized that light signatures coming from space ranging from radio wavelengths to X-rays could be attributed to AGNs. It was assumed that the objects usually had a doughnut-shaped ring—or “torus”—of gas and dust around them. The different brightness and colors associated with the objects were thought to be the result of the angle from which they were being observed and how much of the torus was obscuring the view.

From this, the unified theory of AGNs became the prevalent understanding. The theory guides that if a black hole is being viewed through its torus, it should appear faint. If it is being viewed from below or above the ring, it should appear bright. According to the current study, however, the past research relied too heavily on data from the less obscured objects and skewed research results.

The new study focuses on how quickly black holes are feeding on space matter, or their accretion rates. The research found that the accretion rate does not depend upon the mass of a black hole, it varies significantly depending on how obscured it is by the gas and dust ring.

“This provides support for the idea that the torus structures around black holes are not all the same,” said Ryan Hickox, professor of physics and astronomy and a co-author of the study. “There is a relationship between the structure and how it is growing.”

The result shows that the amount of dust and gas surrounding an AGN is directly related to how much it is feeding, confirming that there are differences beyond orientation between different populations of AGNs. When a black hole is accreting at a high rate, the energy blows away dust and gas. As a result, it is more likely to be unobscured and appear brighter. Conversely, a less active AGN is surrounded by a denser torus and appears fainter.

"In the past, it was uncertain how the obscured AGN population varied from their more easily observable, unobscured counterparts,” said Ananna. “This new research definitively shows a fundamental difference between the two populations that goes beyond viewing angle.”

The study stems from a decade-long analysis of nearby AGNs detected by Swift-BAT, a high-energy NASA X-ray telescope. The telescope allows researchers to scan the local universe to detect obscured and unobscured AGNs.

The research is the result of an international scientific collaboration—the BAT AGN Spectroscopic Survey (BASS)—that has been working over a decade to collect and analyze optical/infrared spectroscopy for AGN observed by Swift BAT.

“We have never had such a large sample of X-ray detected obscured local AGN before,” said Ananna. “This is a big win for high-energy X-ray telescopes.”

The paper builds on previous research from the research team analyzing AGNs. For the study, Ananna developed a computational technique to assess the effect of obscuring matter on observed properties of black holes, and analyzed data collected by the wider research team using this technique.

According to the paper, by knowing a black hole’s mass and how fast it is feeding, researchers can determine when most supermassive black holes underwent most of their growth, thus providing valuable information about the evolution of black holes and the universe.

“One of the biggest questions in our field is where do supermassive black holes come from,” said Hickox. “This research provides a critical piece that can help us answer that question and I expect it to become a touchstone reference for this research discipline.”

Future research could include focusing on wavelengths that allow the team to search beyond the local universe. In the nearer term, the team would like to understand what triggers AGNs to go into high accretion mode, and how long it takes rapidly accreting AGNs to transition from heavily obscured to unobscured.

Researchers contributing to the study include Benny Trakhtenbrot, Tel Aviv University; Claudia Megan Urry, Yale University; and Mike Koss of Eureka Scientific.

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JOURNAL

The Astrophysical Journal

DOI

10.3847/1538-4365/ac5b64 

ARTICLE TITLE

Distribution Functions of DR2 Eddington-ratios, Black Hole Masses, and X-ray Luminosities

ARTICLE PUBLICATION DATE

15-Jul-2022

Pre-teen children believe ‘brilliance’ is a male trait, and this stereotype increases in strength up to the age of twelve

Peer-Reviewed Publication

NANYANG TECHNOLOGICAL UNIVERSITY

 

IMAGE: FIGURE 1. SAMPLE TEST TRIALS FROM THE GENDER-BRILLIANCE IAT. DURING HALF OF THE TRIALS, PARTICIPANTS HAD TO PRESS A KEY TO CATEGORISE THE MALE PHOTOGRAPHS WITH THE GENIUS WORDS. THIS PROCESS WAS REPEATED IN THE SECOND HALF OF THE TRIALS WITH FEMALE PHOTOGRAPHS AND GENIUS WORDS. PARTICIPANTS WITH AN IMPLICIT “BRILLIANCE = MEN” ASSOCIATION WILL REACT FASTER TO TRIALS INVOLVING PICTURES OF MEN THAN PICTURES INVOLVING WOMEN. THE PHOTOGRAPHS HAVE BEEN PROCESSED TO PROTECT THE PRIVACY OF THE VOLUNTEERS. view more 

CREDIT: NTU SINGAPORE

Children hold stereotypical views that ‘brilliance’ is a male trait, and this belief strengthens as they grow up to the age of twelve, researchers from Singapore and the United States have reported.

The study led by Nanyang Technological University, Singapore (NTU Singapore) in collaboration with New York University, was published in the scientific journal Child Development in May 2022. It involved 389 Chinese Singaporean parents and 342 of their children aged 8 to 12.

Tests were carried out to measure the extent to which parents and their children associate the notion of brilliance with men, and to probe the relationship between parents and their children’s views.

The study defined brilliance as an exceptional level of intellectual ability and results showed that children are as likely to associate brilliance with men, as their parents are.

This belief was stronger among older children and stronger among those children whose parents held the same view. 

While previous research on gender stereotypes has found the idea that giftedness is a male trait can emerge at around the age of six, it was not known whether and how this stereotype changes over the course of childhood, until now.  

Lead author of the study, Associate Professor Setoh Peipei from NTU Singapore’s School of Social Sciences, said the Singapore-based study is the first to identify that the tendency to associate brilliance with men (also known as the ‘brilliance equals to men’ stereotype) increases in strength through the primary school years, and reaches the level of belief seen in adults by the age of 13.

“Stereotypical views about how boys are smarter than girls can take root in childhood and become a self-fulfilling prophecy,” said Prof Setoh. “For girls, this may lead them to doubt their abilities, thus limiting their ideas about their interests and what they can achieve in life.”

“Our research work shows parents must also be included in policies and school programmes to effectively combat children’s gender stereotypes from a young age,” she added.

For example, as previous studies have found that parents use different explanation styles for daughters and for sons, the research team said programmes to train parents and teachers to be mindful of balancing their behaviour during interactions with children - especially with girls - could be introduced.

The authors say the study offers evidence to support Singapore’s push to close the gender gap in the Science, Technology, Engineering, and Mathematics (STEM) sectors.

While Singapore has the second highest in the world OECD PISA scores in mathematics, science and reading, a recent study by the Promotion of Women in Engineering, Research, and Science (POWERS) programme at NTU Singapore found that women in Singapore are less confident in their math and science abilities compared to men.[1] Women are also more likely than men to perceive gender barriers to STEM career entry and career progress.

How the study was conducted

The researchers used the Implicit Association Test (IAT) – a commonly-used implicit measure of stereotyping – to evaluate parents’ and children’s behaviour. During the test, participants were asked to categorise photographs of men and women, along with two sets of words. One set of ‘genius words’ referred to the notion of brilliance and included words such as “super-smart” and “genius”, while the other set of words referred to creativity (control attribute).  

During the first half of the trials, participants had to press a key to categorise the male photographs with the genius words. This process was repeated in the second half of the trials with female photographs and genius words (See Figure 1). Participants with an implicit association of men being brilliant will react faster to the task of categorising genius words with the male photographs than the same task with female photographs.

Results revealed an average D score (a metric of the strength of the stereotypical ‘intellectual brilliance = men’ association) of 0.16, indicating that Singaporean children associate brilliance with men more than women[2] and that this stereotypical belief increased in strength with age among the child sample and reached stereotype levels comparable to those of adults by age 12. Thereafter, there was little change in their perspective.

In the second part of the study, the researchers investigated scores from parent-child pairs who took the tests separately but at the same time and found that children’s scores were correlated to their parents’ test scores. This finding suggests that during the earlier years of primary school, parents may play a role in their children’s acquisition of the ‘brilliance equals to men’ stereotype.

Further analysis revealed that as the age of the boys that were tested got older, they were less likely to hold the same stereotypical views of males as more brilliant as their parents. However, for girls, their stereotypes remained closely linked to their parents’ stereotypes throughout the primary school years.

Co-author Andrei Cimpian, Professor of Psychology at New York University said, “This study adds to the evidence that the gender imbalances observed in many prestigious careers are not a function of differences between women and men in their inherent aptitudes or interests. Rather, these imbalances are the product of the messages that young people are getting from those around them about what women and men are supposedly – and supposed to be – like. As a society, we have a responsibility to work toward addressing this issue.”

Moving forward, the research team is studying whether this gender stereotype about brilliance may differently impact primary and secondary school girls’ and boys’ outcomes in math - a core STEM subject that is typically believed to require intellectual brilliance to excel in.

The project investigates various math outcomes that can predict children’s future participation in STEM fields, including math achievement, interest, and confidence in doing math. The researchers hope that by unravelling how the gender stereotype about brilliance functions to divert girls’ and boys’ interests and aspirations from an early age, the project will offer valuable insights into designing interventions to curb the circulation of gender stereotypes and ultimately help to close STEM gender gaps in society.

***END***

 

Notes to Editor:

Paper titled “The acquisition of the gender-brilliance stereotype: Age trajectory, relation to parents' stereotypes, and intersections with race/ethnicity” published in Child Development, 30 May 2022
DOI: 10.1111/cdev.13809

[1] “Closing the STEM gender gap in Singapore”, whitepaper by POWERS, published 4 March 2022

[2] A D score above the neutral point of zero indicates that children found the ‘brilliance = men’ association more cognitively fluent, so it was easier for them to pair men with the concept of brilliance than women during the test.

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JOURNAL

Child Development

DOI

10.1111/cdev.13809 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The acquisition of the gender-brilliance stereotype: Age trajectory, relation to parents' stereotypes, and intersections with race/ethnicity