Invisible currents at the edge: Rice University research team shows how magnetic particles reveal a hidden rule of nature

Rice University

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From left to right, Evelyn Tang, assistant professor of physics and astronomy, and Sibani Lisa Biswal, the William M. McCardell Professor in Chemical Engineering at Rice University. 

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Credit: Alex Becker/Rice University.

If you’ve ever watched a flock of birds move in perfect unison or seen ripples travel across a pond, you’ve witnessed nature’s remarkable ability to coordinate motion. Recently, a team of scientists and engineers at Rice University discovered a similar phenomenon on a microscopic scale, where tiny magnetic particles driven by rotating fields spontaneously move along the edges of clusters driven by invisible “edge currents” that follow the rules of an unexpected branch of physics. The research was published in the journal Physical Review Research.

“When I saw the initial data — with streams of particles moving faster along the edges than in the middle — I said ‘these are edge flows!’ and we got to work exploring this,” said corresponding author Evelyn Tang, assistant professor of physics and astronomy. “What’s very exciting is that we can explain their emergence using ideas from topological physics, a field that became prominent due to quantum computers and exotic materials.”

In their experiments, the team suspended superparamagnetic colloids — think tiny magnetic beads about a hundred times smaller than a grain of sand — in salty water. They then applied a rotating magnetic field, which caused the particles to form crystals in different shapes: Sometimes they formed dense circular clusters, and other times they spread out in sheets with empty holes or “voids.”

The experiment got especially interesting when the particles along the outer edges of these shapes started to move faster than the rest, forming a kind of conveyor belt around the border.

“We call this edge flow,” said co-first author Aleksandra Nelson, a former postdoctoral fellow in Tang’s lab. “It is basically a current that forms naturally around the boundary without anyone pushing it.”

To understand why this occurred, the researchers turned to something called topological physics, which is a way of describing systems where movement or behavior is controlled by the overall shape or layout rather than the exact details.

“Topology is like the highway signs that determines the traffic flow,” said co-author Sibani Lisa Biswal, the William M. McCardell Professor in Chemical Engineering. “Even if there are construction or potholes, the traffic still flows the same way because the route is set by the system’s shape. That’s what topology is — rules that hold up even in messy or noisy conditions.”

In this case, the “rules” predicted that rotating magnetic particles would generate movement along the edges of whatever shape they formed — whether it was a cluster or a void. And that’s exactly what the team observed under the microscope.

Interestingly, the type of motion depended on the shape. When particles formed free-floating clusters, the edge flow caused the whole cluster to spin like a tiny wheel. But when the particles formed larger sheets with voids, the edges still had movement, but the overall structure didn’t rotate.

Tang explained that this phenomenon happened because in clusters, the particles were free to turn together like dancers in a circle. But in sheets with voids, the surrounding material held them in place, so the edge motion had to spread inward instead of rotating. This difference also changed how quickly the entire system reorganized. Clusters could change shape and merge within minutes, while sheets with voids took much longer.

The ability to control how particles move and organize themselves may seem like a niche discovery, but it has broad implications. Understanding how to direct motion in crowded, dynamic systems could inform the design of responsive materials such as targeted drug delivery, adaptive surfaces or swarms of microbots.

“We’re learning how to control collective behavior using simple physical principles,” said co-first author Dana Lobmeyer, a recent graduate in Biswal’s lab. “This is a step toward creating materials that can sense their environment and respond intelligently without needing a computer or instructions.”

Although the experiments used synthetic particles, the team sees parallels in biology too. Many cell clusters rotate during development or healing, raising the possibility that similar physical principles are at work inside living organisms.

“This is the beauty of science,” Tang said. “We’re taking a concept from fundamental math and statistical physics to apply it to everyday materials. It’s a reminder that the same elegant rules can show up right in the lab next door.”

This research was supported by the National Science Foundation and The Kavli Foundation.

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Journal

Physical Review Research

DOI

10.1103/PhysRevResearch.7.023094 

Article Title

Topological edge flows drive macroscopic reorganization in magnetic colloids

 

The US has a new powerful laser

Hitting 2 petawatts, the NSF-funded ZEUS facility at U-M enables research that could improve medicine, national security, materials science and more

University of Michigan

 

Photos in the laser facility  //  Animated fly-through of the ZEUS laser system

 

The ZEUS laser facility at the University of Michigan has roughly doubled the peak power of any other laser in the U.S. with its first official experiment at 2 petawatts (2 quadrillion watts). 

 

At more than 100 times the global electricity power output, this huge power lasts only for the brief duration of its laser pulse—just 25 quintillionths of a second long.

 

"This milestone marks the beginning of experiments that move into unexplored territory for American high field science," said Karl Krushelnick, director of the Gérard Mourou Center for Ultrafast Optical Science, which houses ZEUS.

 

Research at ZEUS will have applications in medicine, national security, materials science and astrophysics, in addition to plasma science and quantum physics. Supported by the U.S. National Science Foundation, ZEUS is a user facility—meaning that research teams from all over the country and internationally can submit experiment proposals that go through an independent selection process. 

 

"One of the great things about ZEUS is it's not just one big laser hammer, but you can split the light into multiple beams," said Franklin Dollar, professor of physics and astronomy at the University of California, Irvine, whose team is running the first user experiment at 2 petawatts. "Having a national resource like this, which awards time to users whose experimental concepts are most promising for advancing scientific priorities, is really bringing high-intensity laser science back to the U.S."

 

Dollar's team and the ZEUS team aim to produce electron beams with energies equivalent to those made in particle accelerators that are hundreds of meters in length.  This would be 5-10 times higher energy than any electron beams previously produced at the ZEUS facility.

 

"We aim to reach higher electron energies using two separate laser beams—one to form a guiding channel and the other to accelerate electrons through it," said Anatoly Maksimchuk, U-M research scientist in electrical and computer engineering, who leads the development of the experimental areas.

 

They hope to do this in part with a redesigned target. They lengthened the cell that holds the gas that the laser pulse rams into, helium in this experiment. This interaction produces plasma, ripping electrons off the atoms so that the gas becomes a soup of free electrons and positively charged ions. Those electrons get accelerated behind the laser pulse-like wakesurfers close behind a speedboat, a phenomenon called wakefield acceleration. 

 

Light moves slower through plasma, enabling the electrons to catch up to it. In a less dense, longer target, the electrons spend more time accelerating before they catch up to the laser pulse, enabling them to hit higher top speeds. 

 

This demonstration of ZEUS's power paves the way for the signature experiment, expected later this year, when the accelerated electrons will collide with laser pulses coming the opposite way. In the moving frame of the electrons, the 3-petawatt laser pulse will seem to be a million times more powerful—a zettawatt-scale pulse. This gives ZEUS its full name of "Zettawatt Equivalent Ultrashort laser pulse System."

 

"The fundamental research done at the NSF ZEUS facility has many possible applications, including better imaging methods for soft tissues and advancing the technology used to treat cancer and other diseases," said Vyacheslav Lukin, program director in the NSF Division of Physics, which oversees the ZEUS project. "Scientists using the unique capabilities of ZEUS will expand the frontiers of human knowledge in new ways and provide new opportunities for American innovation and economic growth."

 

The ZEUS facility fits in a space similar in size to a school gymnasium. At one corner of the room, a laser produces the initial infrared pulse. Optical devices called diffraction gratings stretch it out in time so that when the pump lasers dump power into the pulse, it doesn't get so intense that it starts tearing the air apart. At its biggest, the pulse is 12 inches across and a few feet long. 

 

After four rounds of pump lasers adding energy, the pulse enters the vacuum chambers. Another set of gratings flattens it to a 12-inch disk that is just 8 microns thick—about 10 times thinner than a piece of printer paper. Even at 12 inches across, its intensity could turn the air into plasma, but then it is focused down to 0.8 microns wide to deliver maximum intensity to the experiments.

 

"As a midscale-sized facility, we can operate more nimbly than large-scale facilities like particle accelerators or the National Ignition Facility," said John Nees, U-M research scientist in electrical and computer engineering, who leads the ZEUS laser construction. "This openness attracts new ideas from a broader community of scientists."

 

The road to 2 petawatts has been slow and careful. Just getting the pieces they need to assemble the system has been harder than expected. The biggest challenge is a sapphire crystal, infused with titanium atoms. Almost 7 inches in diameter, it is the critical component of the final amplifier of the system, which brings the laser pulse to full power.

 

"The crystal that we're going to get in the summer will get us to 3 petawatts, and it took four and a half years to manufacture," said Franko Bayer, project manager for ZEUS. "The size of the titanium sapphire crystal we have, there are only a few in the world."

 

In the meantime, jumping from the 300 terawatt power of the previous HERCULES laser to just 1 petawatt on ZEUS resulted in worrying darkening of the gratings. First, they had to determine the cause: Were they permanently damaged or just darkened by carbon deposits from the powerful beam tearing up molecules floating in the imperfect vacuum chamber? 

 

When it turned out to be carbon deposits, Nees and the laser team had to figure out how many laser shots could run safely between cleanings. If the gratings became too dark, they could distort the laser pulses in a way that damages optics further along the path.

 

Finally, the ZEUS team has already spent a total of 15 months running user experiments since the grand opening in October 2023 because there is still plenty of science that could be done with a 1 petawatt laser. So far, it has welcomed 11 separate experiments with a total of 58 experimenters from 22 institutions, including international researchers. Over the next year—between user experiments—the ZEUS team will continue upgrading the system toward its full power.

 

Krushelnick is also the Henry J. Gomberg Collegiate Professor of Engineering and a professor of nuclear engineering and radiological sciences, electrical and computer engineering and physics.

 

Having a team therapist reduces burnout in critical care nurses

American Thoracic Society

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Julie Graham, PhD, APRN, assistant professor at San Diego State University School of Nursing.

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Credit: Julie Graham, PhD, APRN

Session:  B17 — The Power of Team Science: Interdisciplinary Approaches to Pulmonary and Critical Care

One of Us. The Value of Having a Team Therapist to Support Nursing Staff in Critical Care Areas

ATS 2025, San Francisco – Adding a team therapist to support nurses in critical care areas can reduce burnout and improve resiliency, according to research published at the ATS 2025 International Conference.

The study highlights the value of embedding a professional therapist within the care team, rather than directing nurses to seek outside support. It’s a novel approach to supporting nurses’ wellbeing that could help hospitals reduce turnover and absenteeism, resulting in an overall cost savings, said first author Julie Graham, PhD, APRN, ACCNS-AG, assistant professor at San Diego State University School of Nursing.

“It’s very, very expensive to replace a nurse who decides to leave the ICU, so when you have high turnover that can be incredibly costly to the organization,” Dr. Graham said. “The salary for one therapist can potentially save all that money.”

Researchers noted that critical care nurses experience significant mental strain. Many health systems have responded to this concern by offering Employee Assistance Programs (EAP). However, few nurses take advantage of these resources. Other systems have tried training nurses as “peer supporters,” but these may not be adequate to address the team’s mental health needs, as the peer supporters themselves may be experiencing the same trauma.

The new study documents the implementation of an on-staff team therapist during the COVID-19 pandemic at Sharp Chula Vista Medical Center in Chula Vista, California.

Dr. Graham said the facility was heavily impacted by the pandemic, which took an enormous toll on nursing staff. Nurses reported significant levels of mental strain, and the ICU saw a 29 percent rate of nurse turnover.

“Nurses were having emotional breakdowns on a daily basis,” Dr. Graham said. “They were really asking for help.”

Hospital leadership partnered with an affiliated mental health hospital to embed a trained therapist on the care team. After the therapist became a full-time position, turnover began to decline, eventually falling as low as 1 percent. Although that rate wasn’t sustained, turnover remains very low, Dr. Graham said.

For the study, nurse researchers surveyed 116 nurses to measure the impacts of having a therapist on the care team. Compared to outside resources like an EAP, spending time with the onsite team therapist was associated with improvements in job satisfaction, burnout, and resiliency. It also had a positive impact on nurses’ self-efficacy, or their perceived ability to manage their own mental health.

Graham said the goal of the study was to provide evidence for the benefits of an on-staff nurse therapist and introduce the concept to other hospitals.

Next, the nurse scientists are working with researchers from the San Diego State School of Business for a follow-up prospective cohort study to measure outcomes like absenteeism and turnover.

“We want to keep justifying this role and shout it from the rooftops,” Dr. Graham said.

 

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Stars or numbers? How rating formats change consumer behavior

Cornell University

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ITHACA, N.Y. – What’s the difference between a product rating of 3.5 displayed with stars versus standard numerals? It might very well be the difference between a 4 and a 3 rating in the eyes of the consumer, according to new marketing research from the Cornell SC Johnson College of Business.

In six experiments, the researchers found that consumers tend to overestimate fractional star ratings and underestimate fractional numerals. In either case, the ratings can be misleading, potentially causing a company to unknowingly overpromise and underdeliver — or sell its own product short.

“Overestimating Stars, Underestimating Numbers: The Hidden Impact of Rating Formats,” was published May 15 in the Journal of Marketing Research.

“When these pictures communicate a fractional number — say 3.5, where there are three full stars and one-half star — our brain automatically completes this half picture,” said first author Deepak Sirwani, now an assistant professor in the Marketing and Behavioural Science Division at the University of British Columbia. “But when the same rating is communicated using numbers, we focus on the left digit, which is ‘3,’ and that’s why 3.5 feels more like a 3 than a 4. That’s why we underestimate it.”

According to Manoj Thomas, a professor of management at Cornell University, this work is really about the human brain and how it processes images and standard Arabic numerals.

“Our results suggest that the brain representations that are activated when you process stars are completely different from the brain representations that are activated when you process Arabic numerals. That realization was the a-ha! moment,” Thomas said. “Most people don’t realize that, but it’s a huge difference.”

The researchers found consistent results across all six experiments they ran. In study 1, for example, they sought to measure the perceived accuracy of ratings using stars versus numerals. A total of 616 participants were randomly assigned to one of three experiment conditions based on the type of rating symbol used: stars; numerals; or both.

Participants were presented with 17 numeric ratings, from 1 to 5, in increments of 0.25, one at a time and in random order, and were asked to estimate the position of each rating on an unmarked horizontal line, with endpoints 1 and 5.

The participants consistently overestimated the magnitude of fractional star ratings while underestimating the magnitude of the numeric ratings.

The group said their findings demonstrate that prevalent rating formats are misleading, highlighting the need for new industry standards.

“What makes this research powerful is the importance of ratings in the current marketplace,” Sirwani said. “Most of us do not buy anything without checking its rating nowadays, and rating has become as powerful a predictor of purchase as price, or brand or even recommendations from friends and family.”

Other research, he said, has indicated that even a rating jump of 0.2 points can increase sales by up to 300%. “We are showing,” he said, “that sales could potentially increase by orders of magnitude by just showing stars instead of numbers.”

For additional information, see this Cornell Chronicle story.

Cornell University has dedicated television and audio studios available for media interviews.

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Journal

Journal of Marketing Research

DOI

10.1177/00222437251322425 

Article Title

Overestimating Stars, Underestimating Numbers: The Hidden Impact of Rating Formats

Article Publication Date

15-May-2025

 

UK child sexual abuse survivors lack support - report

New research featuring 643 victims presented at Anglia Ruskin University conference

Anglia Ruskin University

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Over 640 victims and survivors of child sexual abuse and exploitation in the UK have shared their stories in a global effort to raise awareness about the realities of sexual violence against children, the challenges of disclosure and recovery, and its enduring impact on their lives.

Their voices are amplified through a powerful report published by the Finnish child-rights organisation Protect Children in collaboration with the International Policing and Public Protection Research Institute (IPPPRI), part of Anglia Ruskin University in England.

At IPPPRI25 - the research institute’s annual conference dedicated to tackling online harms - on Monday, 19 May, Protect Children is publishing insights from 643 victims and survivors of childhood sexual violence perpetrated in the UK. The responses have been analysed by researchers from IPPPRI.

The groundbreaking report reveals unprecedented information about crimes of sexual violence against children in the UK, shedding light on the critical gaps in the local systems for preventing child sexual abuse and exploitation, and for supporting those affected.

The evidence was collected through an innovative Global Our Voice Survivor Survey that aims to hear and amplify the long-silenced voices and wisdom of those who endured sexual violence in childhood. Utilising a novel methodology, the survey has successfully reached out to over 23,000 victims and survivors worldwide.

Professor Samantha Lundrigan, Director of IPPPRI at Anglia Ruskin University, said: “Today at IPPPRI25, we are presenting, together with Protect Children, important findings focused on how research can inform real-world practice in responding to child sexual abuse and exploitation globally. We must understand the systemic factors that enable sexual violence against children so that we can act.”

Despite the severe and long-lasting impacts of child sexual abuse and exploitation, more than half of victims and survivors in the UK reported not receiving any support.

Lea Kamitz, Dawes Postdoctoral Research Fellow at IPPPRI, Anglia Ruskin University, said: “Much of the abuse described by the UK respondents happened decades ago and we know that the nature of child sexual abuse has changed, with so many young people now being victimised online. We must recognise the harm suffered by victims and survivors and ensure access to long-term support services.”

The presenting researchers unveil a concerning lack of response to child sexual abuse in the UK. Despite severe and long-lasting emotional, physical, and psychological impacts, more than half of survivors have not received any support to cope with these. The results were compared between the Five Eyes countries*, revealing that survivors in the UK were the least likely to receive support.

Another distressing insight highlights that over a half of the surveyed victims and survivors were first subject to sexual violence when they were 3 to 9 years old. Furthermore, victims and survivors reported suffering multiple forms of sexual abuse during their childhood ranging from inappropriate touching while clothed to the most severe forms of sexual abuse and exploitation.

Nine out of 10 survivors said that the perpetrator was someone they knew from before, with almost half reporting the perpetrator lived in the same household.

Executive Director of Protect Children, Nina Vaaranen-Valkonen, who has a lifetime of experience working as a psychotherapist with survivors of childhood sexual violence, said: “The voices of survivors are a resounding call to action.

“I have learned from my patients that disclosure and healing from child sexual abuse is an ongoing and often invisible struggle and for many, simply surviving is an act of immense strength – and that truth demands our support, our compassion, and sustained change.”

The researchers emphasised that 21% of survivors have never disclosed the abuse. Childhood sexual violence is already a very hidden form of criminality and it is further complicated by the challenges of disclosure. The disclosure may take up years or even decades – the striking proportion of two in five victims and survivors in the UK shared that it took them more than 21 years.

The insights from survivors form a call to action, urging communities, policymakers, and societies worldwide to recognise their pain and resilience and to come together in the mission to end child sexual abuse and exploitation.

One survivor of childhood sexual violence in the UK, who took part in the Global Our Voice Survivor Survey, said: “I feel a bit sad for the child I was, but I am very glad to be able to give evidence of my experience to help inform others and build knowledge internationally about sexual abuse of children.”

Eva Díaz Bethencourt, Specialist and Human Rights Lawyer at Protect Children, said: “We cannot continue to fail victims and survivors seeking justice and support; we must ensure they receive the recognition, reparation, and support they deserve. We cannot undo the damage that has already been done, but we must ensure that no more children have to suffer further violence. All children should live a childhood free from any form of abuse.”

The powerful report presented by Protect Children and IPPPRI underscores the urgent need for stronger trauma-informed prevention and response systems in the UK. The full report is available here: https://www.suojellaanlapsia.fi/en/post/our-voice-survivors-in-the-uk

 

* The Global Our Voice Survivor Survey was developed by Protect Children, and the data analysis of the report “Our Voice Survivors in the UK: Experiences of Victims and Survivors of Child Sexual Abuse and Exploitation”, was conducted in collaboration with IPPPRI. The report analyses the data collected from 643 respondents who suffered childhood sexual abuse in the UK and 624 in other Five Eyes countries (Australia, Canada, New Zealand, US). The Five Eyes alliance is an intelligence-sharing partnership among these nations, which also collaborates closely in law enforcement and child protection efforts.

 

A head and a hundred tails: how a branching worm manages reproductive complexity

International research team led by Göttingen University produces genetic activity map for rare worm

University of Göttingen

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Male stolen (right hand side): one of the independent reproductive units – growing at the tip of a branch of the worm’s body. It has sprouted eyes and will go swimming free to find a stolon of the opposite sex with which to reproduce. The research showed stolons showed localised upregulation of genes related to eye development. Length of the stolon: approx. 1.5 millimetres.

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Credit: Maria Teresa Aguado and Guillermo Ponz-Segrelles; BMC Genomics, DOI: 10.1186/s12864-025-11587-w; licensed under CC BY 4.0

Scientists have uncovered the genetic underpinnings of one of the ocean’s most bizzare animals: a branching marine worm named Ramisyllis kingghidorahi that lives inside sea sponges and reproduces in a truly extraordinary way. Living hidden in tropical waters, this worm grows multiple body branches within a host sponge, each tail capable of producing separate living reproductive units called “stolons”. But how does a single animal coordinate sexual reproduction across so many branches? To find out, researchers led by the University of Göttingen analysed gene expression across different body regions and between male, female and juvenile specimens. This provides the first complete “genetic activity map” – or transcriptome – of any branching worm, revealing how this creature manages to control reproduction across its branching body. Their findings were published in BMC Genomics.

 

The researchers found clear patterns in their analyses: differences in gene activity were more pronounced between different body regions in the same worm than between the sexes. The stolons – short-lived reproductive units that break off from the branches and swim away to mate – had the most distinctive genetic signatures when comparing males and females, probably reflecting their specialised role in gamete production and metamorphosis. “We were surprised to find that the head of the worm, which was previously thought to house a sex-specific control system, didn’t show the dramatic differences we expected between males and females,” said Dr Guillermo Ponz-Segrelles, former researcher at the Autonomous University of Madrid. “Instead, the stolons emerged as the true hotspots of gene activity during sexual development.”

 

An overlooked but key feature of the reproductive stolons is that they sprout eyes before detaching from the main worm body in search of a mate. This study revealed upregulation of genes related to eye development, providing the first clues about how the tip of a branch of the worm body metamorphoses into an independent stolon. Interestingly, the data also hint at the possibility of partial genome duplication in Ramisyllis, which may help explain the complexity of its biology and reproductive system. Despite some challenges in identifying conserved signalling pathways, the results point to a unique genetic toolkit in Ramisyllis and highlight how little we still know about reproduction in marine invertebrates. “This worm and its surreal, tree-like body made headlines around the world in 2021 and 2022, yet it continues to amaze us,” said Thilo Schulze, PhD researcher at Göttingen University.” It challenges our understanding of how animal bodies can be organized, and how such strange forms of reproduction are orchestrated at the molecular level.” With many aspects of branching worms’ reproductive biology still a mystery, the team hopes this new genetic resource will open the door to deeper investigations into how life evolves in unexpected directions – even in the hidden corners of our oceans.

Further details and short clips about this fascinating worm are available on YouTube here: https://youtu.be/MO1c23m6XkA, https://youtu.be/rwgil23MzyM, https://youtu.be/q2l_OgedY0I

 

Original publication: Ponz-Segrelles et al. (2025) Sex-specific differential gene expression during stolonization in the branching syllid Ramisyllis kingghidorahi (Annelida, Syllidae). BMC Genomics 2025. DOI: 10.1186/s12864-025-11587-w. Full text also available here: https://rdcu.be/ejnKq

Close-up of female stolen – one of the independent reproductive units – from the worm Ramisyllis kingghidorahi. It has aleady sprouted eyes and is swimming free to find a stolon of the opposite sex with which to reproduce. Total length of the stolon: approx. 1.5 millimetres.

Credit

Maria Teresa Aguado and Guillermo Ponz-Segrelles; Organisms Diversity & Evolution, DOI: 10.1007/s13127-021-00538-4; licensed under CC BY 4.0

The branching worm, Ramisyllis kingghidorahi, at home: this sponge is its underwater natural habitat

Credit

Toru Miura; BMC Genomics, DOI: 10.1186/s12864-025-11587-w; lizensiert nach CC BY 4.0

Journal

BMC Genomics

DOI

10.1186/s12864-025-11587-w 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Sex-specific differential gene expression during stolonization in the branching syllid Ramisyllis kingghidorahi (Annelida, Syllidae).