How a legal loophole allows unsafe ingredients in US foods

Gaps in FDA oversight enable the food industry to determine which substances are “generally recognized as safe”

New York University

The Food and Drug Administration (FDA) is tasked with overseeing the safety of the U.S. food supply, setting requirements for nutrition labeling, working with companies on food recalls, and responding to outbreaks of foodborne illness. But when it comes to additives already in our food and the safety of certain ingredients, FDA has taken a hands-off approach, according to a new article in the American Journal of Public Health.

The current FDA process allows the food industry to regulate itself when it comes to thousands of added ingredients—by determining for itself which ingredients should be considered “generally recognized as safe,” or GRAS—and deciding on their own whether or not to disclose the ingredients’ use and the underlying safety data to the FDA. As a result, many new substances have been added to our food supply without any government oversight.

“Both the FDA and the public are unaware of how many of these ingredients—which are most commonly found in ultra-processed foods —are in our food supply,” said Jennifer Pomeranz, associate professor of public health policy and management at NYU School of Global Public Health and study’s first author.

Classifying GRAS

Since 1958, the FDA has been responsible for evaluating the safety of new chemicals and substances added to foods before they go to market. However, food safety laws distinguish between “food additives” and “GRAS” ingredients. While compounds considered “food additives” must be reviewed and approved by the FDA before they are used in foods, ingredients considered GRAS are exempt from these regulations.

The GRAS designation was initially established for ingredients already found in foods—for instance, vinegar and spices. But under a rule used since 1997, the FDA has allowed the food industry to independently determine which substances fall into this category, including many new substances added to foods. Rather than disclose the new use of these ingredients and the accompanying safety data for FDA review, companies can do their own research to evaluate an ingredient’s safety before going to market, without any notification or sharing of the findings. The FDA suggests—but does not require—that companies voluntarily notify the agency about the use of such substances and their findings, but in practice, many such substances have been added without notification.

In their analysis, the researchers review the history of the FDA’s and industry’s approach around adding these new compounds to foods and identify the lack of any real oversight. This includes a federal court case in 2021 upholding the FDA’s hands-off approach.

“Notably, the court did not find that the FDA’s practices on GRAS ingredients support the safety of our food supply,” said Pomeranz. “The court only ruled that the FDA’s practice was not unlawful.”

“As a result of the FDA’s policy, the food industry has been free to ‘self-GRAS’ new substances they wish to add to foods, without notifying FDA or the public,” said study senior author Dariush Mozaffarian, director of the Food is Medicine Institute and distinguished professor at the Friedman School of Nutrition Science and Policy at Tufts University. “There are now hundreds, if not thousands, of substances added to our foods for which the true safety data are unknown to independent scientists, the government, and the public.”

What’s on our shelves?

According to the researchers, the FDA also lacks a formal approach and adequate resources to review those food additives and GRAS substances already on the market. After an ingredient is added to foods, if research later suggests harms, the FDA can review the new data and, if needed, take action to reduce or remove it from foods. In a rare exception, the FDA announced in March that it would be reviewing 21 chemicals found in foods, including several food ingredients—a tiny fraction of the thousands of food additives and GRAS substances used today.

An example of the 21 food additives to be reviewed is potassium bromate, a chemical added to baked goods and drinks with evidence that it may cause cancer. Potassium bromate is banned in Europe, Canada, China, and Japan; California recently passed a law to ban its use, along with three other chemicals, and similar bills have been introduced in Illinois, New York, and Pennsylvania.

“This is a stark example of the FDA’s regulatory gap,” said Pomeranz. “We’re seeing states starting to act to fill the regulatory void left by the FDA’s inaction over substances increasingly associated with harm.”

The FDA’s oversight of GRAS ingredients on the market is also limited. The agency rarely revokes GRAS designation (an FDA inventory only shows 15 substances that were considered GRAS and then later determined to not be), nor does the FDA review foods on an ongoing basis with GRAS ingredients that can be safe when added at low levels but not in large quantities—for instance, caffeine, salt, and sugar.

“In 1977, the FDA approved caffeine as a GRAS substance for use in sodas at a low level: 0.02 percent,” said Pomeranz. “But today, caffeine is added to energy drinks at levels far exceeding this, which is causing caffeine-related hospitalizations and even deaths. Given that the FDA regulates the use of GRAS substances, the agency could set limits on the amount of caffeine in energy drinks.”

“The sheer number of GRAS substances and food additives on the market, combined with the lack of knowledge about the existence of self-GRAS ingredients, insufficient resources, and documented time delays even for well-supported action, renders reliance on post-market authority flawed and unreliable to ensure a safe food supply. FDA is only starting to utilize its post-market powers to review a tiny number of ingredients in the food supply, even though evidence of harm has been present for decades,” said study co-author Emily Broad Leib, director of Harvard Law School Center for Health Law and Policy Innovation and founding director of the Harvard Law School Food Law and Policy Clinic.

Stronger protections                                                           

The authors’ analysis provides the FDA and Congress with several potential actions to better assess and oversee the safety of both GRAS substances and food additives. This could include a new requirement that companies must publicly notify the FDA of the use of GRAS ingredients, and share their underlying safety data, before they are put in foods; creating a robust review process to reevaluate the safety of GRAS ingredients and food additives once they are already on the market; and clarifying the distinction between GRAS ingredients and food additives.

In order to fund this stronger oversight of the food supply, the researchers suggest that Congress could allocate additional resources to the FDA or establish a user fee program in which food companies pay for the FDA to review the safety of their ingredients before they are added to foods.

“Both the FDA and Congress can do more to enable the FDA to meet its mission of ensuring a safe food supply,” said Pomeranz.

The research was supported by the National Institutes of Health (2R01HL115189-06A1).

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Journal

American Journal of Public Health

DOI

10.2105/AJPH.2024.307755 

Article Title

Regulation of Added Substances in the Food Supply by the Food and Drug Administration Human Foods Program

Article Publication Date

8-Aug-2024

 

Many survey respondents rated seeking out sexually explicit ‘deepfakes’ as more acceptable than creating or sharing them

University of Washington

Content warning: This post contains details of sharing intimate imagery without consent that may be disturbing to some readers.

While much attention on sexually explicit “deepfakes” has focused on celebrities, these non-consensual sexual images and videos generated with artificial intelligence harm people both in and out of the limelight. As text-to-image AI models grow more sophisticated and easier to use, the volume of such content is only increasing. The escalating problem led Google to announce last week that it will work to filter out these deepfakes in search results, and the Senate recently passed a bill allowing victims to seek legal damages from deepfake creators.

Given this rising attention, researchers at the University of Washington and Georgetown University wanted to better understand public opinions about the creation and dissemination of what they call “synthetic media.” In a survey, 315 people largely found creating and sharing synthetic media unacceptable. But far fewer responses strongly opposed seeking out these media — even when they portrayed sexual acts.

Yet previous research has shown that other people viewing image-based abuse, such as nudes shared without consent, harms the victims significantly. And in nearly all states, including Washington, creating and sharing such nonconsensual content is a crime.

“Centering consent in conversations about synthetic media, particularly intimate imagery, is key as we look for ways to reduce its harms — whether that’s through technology, public messaging or policy,” said lead author Natalie Grace Brigham, who was a UW master's student in the Paul G. Allen School of Computer Science & Engineering while completing this research. “In a synthetic nude, it’s not the subject’s body — as we’ve typically considered it — that’s being shared. So we need to expand our norms and ideas about consent and privacy to account for this new technology.”

The researchers will present their findings Aug. 13 at the 20th Symposium on Usable Privacy and Security in Philadelphia.

“In some sense, we’re at a new frontier in how people’s rights to privacy are being violated,” said co-senior author Tadayoshi Kohno, a UW professor in the Allen School. “These images are synthetic, but they still are of the likeness of real people, so seeking them out and viewing them is harmful for those people.”

The survey, which the researchers conducted online through Prolific, a site that pays people to respond on a variety of topics, asked U.S. respondents to read vignettes about synthetic media. The team altered variables in these scenarios like who created the synthetic media (an intimate partner, a stranger), why they created it (for harm, entertainment or sexual pleasure), and what action was shown (the subject performing a sexual act, playing a sport or speaking).

The respondents then ranked various actions around the scenarios — creating the video, sharing in different ways, seeking it out — from “totally unacceptable” to “totally acceptable” and explained their responses in a sentence or two. Finally, they filled out surveys on consent and demographic information. The respondents were over the age of 18 and were 50% women, 48% men, 2% non-binary and 1% agender.

Overall, respondents found creating and sharing synthetic media unacceptable. Their median totally unacceptable or somewhat unacceptable ratings were 90% for creating these media and 94% for sharing them. But the median of unacceptable ratings for seeking out synthetic media was only 53%.

Men were more likely than respondents of other genders to find creating and sharing synthetic media acceptable, while respondents who had favorable views of sexual consent were more likely to find these actions unacceptable.

“There has been a lot of policy talk about preventing synthetic nudes from getting created. But we don't have good technical tools to do that, and we need to simultaneously protect consensual use cases,” said co-senior author Elissa M. Redmiles, an assistant professor of computer science at Georgetown University. “Instead, we need to change social norms. So we need things like deterrence messaging on searches — we’ve seen that be effective at reducing the viewing of child sexual abuse images — and consent-based education in schools focused on this content.”

Respondents found scenarios in which intimate partners created synthetic media of people playing sports or speaking for the intent of entertainment the most acceptable. Conversely, nearly all respondents found it totally unacceptable to create and share sexual deepfakes of intimate partners with the intent of harm.

Respondents’ reasoning varied. Some found synthetic media unacceptable only if the outcome was harmful. For example, one respondent wrote, “It’s not harming me or blackmailing me… [a]s long as it doesn’t get shared I think it’s okay.” Others, though, centered their right to privacy and right to consent. “I feel it’s unacceptable to manipulate my image in such a way — my body and how it looks belongs to me,” wrote another.

The researchers note that future work in this space should explore the prevalence of non-consensual synthetic media, the pipelines for how it’s created and shared, and different methods to deter people from creating, sharing and seeking out non-consensual synthetic media.

“Some people argue that AI tools for creating synthetic images will have benefits for society, like for the arts or human creativity,” said co-author Miranda Wei, a doctoral student in the Allen School. “However, we found that most people thought creating synthetic images of others in most cases was unacceptable — suggesting that we still have a lot more work to do when it comes to evaluating the impacts of new technologies and preventing harms.”

This research was funded in part by the National Science Foundation and the Google PhD Fellowship Program.

For more information, contact Brigham at nbrigham@uw.edu, Wei at weimf@cs.washington.edu, Kohno at yoshi@cs.washington.edu and Redmiles at elissa.redmiles@georgetown.edu.

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Article Title

“Violation of my body:” Perceptions of AI-generated non-consensual (intimate) imagery

Article Publication Date

13-Aug-2024

 

ADHD symptoms in autistic children linked to neighborhood conditions

Study finds poverty, lack of services may play a role

University of California - Davis Health

Autistic youth who were born in underserved neighborhoods are more likely to have greater attention deficit hyperactivity disorder (ADHD) symptoms than those born in communities with more resources. This is one finding of a new study led by researchers at the UC Davis MIND Institute.  

This is the first time researchers have investigated how neighborhood factors are associated with ADHD in autistic and non-autistic children. The study provides new insights into mental health conditions and has the potential to inform public policy changes to improve health equity.

It was published in the journal JCPP Advances.

“We found that some neighborhood factors are strongly related to ADHD symptoms in autistic children,” said Catrina Calub, the first author on the paper. Calub is a postdoctoral researcher in the laboratory of Julie Schweitzer, a professor in the Department of Psychiatry and Behavioral Sciences and the MIND Institute.  

“In this study, we didn't find this effect in typically developing kids or in kids with other developmental disabilities, only in the autistic children. It suggests that when autistic kids live in neighborhoods with fewer resources, they tend to have more pronounced ADHD symptoms,” Calub said.

ADHD symptoms can include higher rates of inattention, hyperactivity and impulsive behavior.It is associated with:

• Challenges in school performance and relationships with friends
• Lower self-esteem and greater risk for anxiety and depression
• Higher potential for substance use disorders and accidents
• Emotional dysregulation and conduct problems

Study expands findings from long-term research

The researchers used data from two studies: the decades-long Childhood Autism Risks from Genetics and the Environment (CHARGE) study led by Irva Hertz-Picciotto at the MIND Institute and the ReCHARGE follow-up project.

CHARGE and ReCHARGE assess how genetics, environment and other factors affect development from early childhood (2–5 years) through adolescence (8-20 years).  

The team looked at 246 autistic children, 85 with developmental delays (without autism), and 193 who were neurotypical. Then, they applied the Child Opportunity Index, which uses census data to track over 30 neighborhood traits. These traits include socioeconomics, green space, single-parent households and concentration of early childhood education centers.

The index encompasses three domains: education, health and environment, and social and economic resources. Higher scores are linked to better childhood health. Of the three domains, the education and social and economic resources scores were most strongly related to ADHD symptoms.

The analysis showed the Child Opportunity Index scores at birth were a strong predictor for ADHD symptoms in adolescence in the autistic children but not in the other groups. Calub noted that the finding was unexpected.

“These results are quite concerning,” Calub said. “Those with both autism and ADHD are already more likely to have additional challenges — behaviorally, cognitively, emotionally and socially. Being born in a low-income neighborhood puts them at an even greater disadvantage. This just adds to the evidence that more resources are needed for underserved areas and specifically for those who have conditions like autism.”

The need for a larger, more diverse sample

Calub pointed out that more research is needed to determine if the results would apply to a larger group.

"It will be important for future studies to be larger and more diverse. That should help us learn whether neighborhood conditions might also influence ADHD symptoms in other groups such as youth without autism, or in Black, Asian and Native American individuals, who were under-represented in our sample," Calub added.

These findings also offer clues for how to target preventive strategies to reduce the risk of increased ADHD symptoms, noted Schweitzer, who was also a co-author on the study.

“ADHD is highly prevalent in the general population and is common in autistic youth. If we can find ways to increase resources in these neighborhoods, we have the potential to improve academic, social, mental and physical health outcomes, particularly for autistic youth, and also decrease long-term economic costs,” Schweitzer explained.

Calub and Schweizer believe the study’s findings should encourage policymakers to provide more resources for underserved communities. In addition, they hope including the Child Opportunity Index and other neighborhood metrics could provide new insights into future studies to inform policy.

Co-authors on the study include Irva Hertz-Picciotto and Deborah Bennett, both in the Department of Public Health Sciences at UC Davis. Read the full study.

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Journal

JCPP Advances

DOI

10.1002/jcv2.12267 

Article Title

Examining the association of neighborhood conditions on attention-deficit/hyperactivity disorder symptoms in autistic youth using the child opportunity index 2.0

Steady flight of kestrels could help aerial safety soar

A new joint study by RMIT and the University of Bristol has revealed secrets to the remarkably steady flight of kestrels and could inform future drone designs and flight control strategies.

RMIT University

 

image: 

A Nankeen Kestrel

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Credit: RMIT

A new joint study by RMIT and the University of Bristol has revealed secrets to the remarkably steady flight of kestrels and could inform future drone designs and flight control strategies.  

Watch video: YouTube 

Making drones safer and more stable in turbulent conditions, or in cities where wind gusts from tall buildings make flying more difficult, makes applications like parcel delivery, food delivery and environmental monitoring more feasible, more often.  
 
The study conducted in RMIT’s Industrial Wind Tunnel facility – one of the largest of its kind in Australia – is the first to precisely measure the stability of a Nankeen Kestrel’s head during hovering flight, finding movement of less than 5mm during hunting behaviour.  
 
“Typically, aircraft use flap movements for stabilisation to achieve stability during flight,” said RMIT lead researcher Dr Abdulghani Mohamed.  
 
“Our results acquired over several years, show birds of prey rely more on changes in surface area, which is crucial as it may be a more efficient way of achieving stable flight in fixed wing aircraft too.”  
 
Anatomy of steady flight  

Kestrels and other birds of prey are capable of keeping their heads and bodies extremely still during hunting. This specialised flight behaviour, called wind hovering, allows the birds to ‘hang’ in place under the right wind conditions without flapping. By making small adjustments to the shape of their wings and tail, they can achieve incredible steadiness. 
 
Thanks to advancements in camera and motion capture technology, the research team was able to observe two Nankeen Kestrels, trained by Leigh Valley Hawk and Owl Sanctuary, at high resolution. 
 
Fitted with reflective markers, the birds’ precise movements and flight control techniques during non-flapping flight were tracked in detail for the first-time. 

“Previous studies involved birds casually flying through turbulence and gusts within wind tunnels; in our study we tracked a unique wind hovering flight behaviour whereby the birds are actively maintaining extreme steadiness, enabling us to study the pure control response without flapping,” said Mohamed. 
 
By mapping these movements, the researchers gained insights that could be utilised to achieve steadier flight for fixed wing aircrafts. 
 
“The wind hovering behaviour we observed in kestrels is the closest representation in the avian world to fixed wing aircraft,” said Mohamed.  
 
“Our findings surrounding the changes in wing surface area could be applied to the design of morphing wings in drones, enhancing their stability and making them safer in adverse weather.” 
 
The issue with current drones 
 
Associate Professor of Bio-Inspired Aerodynamics at Bristol University and joint last author, Dr Shane Windsor, said the usefulness of current fixed wing unmanned aerial vehicles (UAV’s) was significantly decreased by their inability to operate in gusty wind conditions.  
 
“UAV’s are being used in the UK to deliver post to remote islands, but their operation time is limited because of regular gusty conditions.  
 
“Current commercial fixed wing aircraft have to be designed with one fixed geometry and optimised to operate at one flight condition. 
 
“The advantage of morphing wings is that they could be continually optimised throughout a flight for a variety of conditions, making the aircraft much more manoeuvrable and efficient.” 
 
Next steps  
 
The team now aims to further their research by examining the birds under gusty and turbulent conditions, which would see further learnings in stable flight with the goal of allowing UAVs to operate more safely and more often. 

While initially focused on smaller aerial vehicles, the team hopes to simplify the data collected so that it can be adapted for larger scale aircraft.  
 
‘Steady as they hover: kinematics of kestrel wing and tail morphing during hovering flights’ published in the Journal of Experimental Biology (https://doi.org/10.1242/jeb.247305) is a collaboration between Mario Martinez Groves-Raines, George Yi, Matthew Penn, Simon Watkins, Shane Windsor and Abdulghani Mohamed. 
 
The team acknowledges Mr Martin Scuffins from the Leigh Valley Hawk and Owl Sanctuary, for supporting the project and sharing expertise and knowledge critical to the project’s success.

Hovering in a wind tunnel 

A Nankeen Kestrel hovering in the RMIT University wind tunnel

Fitting sensors 

Martin Scuffins from the Leigh Valley Hawk and Owl Sanctuary and RMIT's Dr Abdulghani Mohamed fitting sensors to the kestrel in RMIT's wind tunnel facility.

Credit

RMIT

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Journal

Journal of Experimental Biology

DOI

10.1242/jeb.247305 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Steady as they hover: kinematics of kestrel wing and tail morphing during hovering flights

Article Publication Date

8-Aug-2024

Glossy black-cockatoos prefer the fruits of ancient rocks

University of Adelaide

 

image: 

A glossy black-cockatoo feeding in a sheoak tree.

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Credit: Ian Buick

New research from the University of Adelaide has shown that glossy black-cockatoos prefer to feed from trees growing in acidic soils.

Glossy black-cockatoos are seed-eating birds that feed almost exclusively on the cones of drooping sheoak trees. However, counterintuitively, they select trees that grow on the poorest soils found on ancient sedimentary rocks.

“Sheoak trees are three times more likely to be used as feeding trees if they are growing on non-limestone sedimentary rocks,” says Dr Gay Crowley, from the University of Adelaide’s School of Social Sciences.

Dr Crowley compared 6,543 feeding records with 23,484 sheoak records from New South Wales to make this discovery. She found that soil type has a direct influence on the way glossy black-cockatoos use the environment by comparing glossy black-cockatoo feeding records with soils and rocks on Kangaroo Island.

“Sheoaks gain their nutrition through fungal associations, rather than from the soil, and their associated fungi thrive on poor soils,” says Dr Crowley, whose research was published in the journal PLOS ONE.

“Many iconic Australian animals, such as bilbies, potoroos, bettongs and bandicoots, feed directly on soil fungi – including native truffles. The same pathways are likely to be responsible for their distribution in the environment.”

Glossy black-cockatoos are one of Australia’s five species of black-cockatoos and can be found across eastern Australia as well as on Kangaroo Island in South Australia. The species is listed as endangered in South Australia, and as vulnerable throughout the rest of its distribution.

To ensure the long-term survival of species that depend on soil fungi, especially the glossy black-cockatoo, Dr Crowley says conservation efforts need to consider the value of habitats on poor soils.

“Conservation efforts often prioritise the richest, most fertile parts of the landscape. This is because many rare animals, such as greater gliders and powerful owls, are most abundant in forests growing on rich soils derived from basalt or limestone,” says Dr Crowley.

“However, many other animals, such as potoroos, bandicoots, and glossy black-cockatoos may be best protected by preserving habitats on infertile soils.”

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Journal

PLoS ONE

DOI

10.1371/journal.pone.0308323 

Are birds flying atoms?

Physical and biological systems are different. But are they? A new study on JSTAT observes that similarities might be greater than we think

Sissa Medialab

 

image: 

Distance Vs Topological Relations

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Credit: Material provided by the author of the paper, Julien Tailleur

A crowd or a flock of birds have different characteristics from those of atoms in a material, but when it comes to collective movement, the differences matter less than we might think. We can try to predict the behavior of humans, birds, or cells based on the same principles we use for particles. This is the finding of a new study published in the Journal of Statistical Mechanics: Theory and Experiment, JSTAT, conducted by an international team that includes the collaboration of MIT in Boston and CNRS in France. The study, based on the physics of materials, simulated the conditions that cause a sudden shift from a disordered state to a coordinated one in "self-propelled agents" (like biological ones).

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“In a way, birds are flying atoms,” explains Julien Tailleur, from MIT Biophysics, one of the authors of the research. “It may sound strange, but indeed, one of our main findings was that the way a walking crowd moves, or a flock of birds in flight, shares many similarities with the physical systems of particles.”

As Tailleur explains, in the field of collective movement studies, it has been assumed that there is a qualitative difference between particles (atoms and molecules) and biological elements (cells, but also entire organisms in groups). It was especially believed that the transition from one type of movement to another (for example, from chaos to an orderly flow, known as a phase transition) was completely different.

The crucial difference for physicists in this case has to do with the concept of distance. Particles moving in a space with many other particles influence each other primarily based on their mutual distance. For biological elements, however, the absolute distance is less important. “Take a pigeon flying in a flock: what matters to it are not so much all the closest pigeons, but those it can see.” In fact, according to the literature, among those it can see, it can only keep track of a finite number, due to its cognitive limits. The pigeon, in the physicists' jargon, is in a “topological relationship” with other pigeons: two birds could be at quite a large physical distance, but if they are in the same visible space, they are in mutual contact and influence each other.

It was long believed that this type of difference led to a completely different scenario for the emergence of collective motion  “Our study, however, suggests that this is not a crucial difference,” continues Tailleur.

“Obviously, if we wanted to analyze the behavior of a real bird, there are tons of other complexities that are not included in our model. Our field follows an advice attributed to Einstein, namely that if you want to understand a phenomenon, you have to make it ‘as simple as possible, but not simpler’. Not the simplest possible, but the one that removes all complexity that is not relevant to the problem. In the specific case of our study, this means that the difference that is real and exists - between physical distance and topological relationship - does not alter the nature of the transition to collective motion.”

The model used by Tailleur and colleagues is inspired by the behavior of ferromagnetic materials. These materials have - as the name suggests - magnetic properties. At high temperature or low density, the spins (simplifying: the direction of the magnetic moment associated with electrons) are oriented randomly due to the large thermal fluctuations and are therefore disorderly. However, at low temperatures and high density, the interactions between the spins dominate the fluctuations and a global orientation of the spins emerges (imagining them as many aligned small compass needles).

“My colleague Hugues Chaté realized twenty years ago that, if the spins were to move in the direction in which they point, they would order through a discontinuous phase transition, with the sudden apparition of large groups of spins moving together, much like flocks of birds in the sky”, says Tailleur. This is very different from what happens in a passive ferromagnet, where the emergence of order occurs gradually. Until recently, physicists believed that biology-inspired models in which particles align with their `topological neighbors’ would also experience a continuous transition. In the model used in the study, Tailleur and colleagues showed that, instead, a discontinuous transition is observed, even if the topological relationship instead of distance is used, and that this scenario should apply to all such models. “Within some limits, the details of how you align is irrelevant”, says Tailleur, “and our work shows that this type of transition should be generic.” 

Another finding is that in the model used, stratified flows form within the larger group, which is akin to what we also observe in reality: it is rare for a mass of people to move all together in one direction; rather, we see within it the motion of finite groups, distinguishable flows that follow slightly different trajectories.

These statistical models, based on the physics of particles, can therefore also help us understand biological collective movement, concludes Tailleur. “The road towards understanding collective motion as we see it in biology—and using it to design new materials—is still long, but we are making progress!”

  

In a model of self-propelled particles aligning with their topological neighbors, one observes the formation of traveling bands (in green), typical of discontinuous transitions. The particle colors encode their orientations.

Credit

Material provided by the author of the paper, Julien Tailleur

Distance Vs Topological relations +  traveling bands 

Credit

Material provided by the author of the paper, Julien Tailleur

Video with model simulation [VIDEO] |

In the video, you can see how coherent collective motion waves emerge from the random movement of particles

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Journal

Journal of Statistical Mechanics Theory and Experiment

DOI

10.1088/1742-5468/ad6428 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Fluctuation-Induced First Order Transition to Collective Motion

Article Publication Date

8-Aug-2024