The safest cabin layout for efficient aircraft evacuation

To evacuate quickly in case of an emergency, elderly passengers, who may be limited in dexterity, should be evenly distributed among aircraft cabins.

American Institute of Physics

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A visualization of the constructed cabin model the researchers used to simulate evacuation scenarios.

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Credit: Zhao et al.

WASHINGTON, March 31, 2026 — In case of an emergency, the Federal Aviation Administration requires aircraft to be able to evacuate within 90 seconds. However, as the median age of the global population increases, the growing number of elderly airline passengers poses new challenges during emergency situations.

In AIP Advances, by AIP Publishing, an international collaboration of researchers simulated 27 different evacuation scenarios in case of a dual-engine fire in an Airbus A320, one of the most common narrow-body aircraft in the world. They compared three different cabin layouts with three different ratios of passengers over the age of 60 and three different distributions of those passengers.

“While a dual-engine fire scenario is statistically rare, it falls under the broader category of dual-engine failures and critical emergencies in aviation. History has shown that dual-engine failures and emergencies, such as the famous ‘Miracle on the Hudson’ involving Captain Sullenberger, can happen and lead to severe consequences,” said author Chenyang (Luca) Zhang. “Our study focuses on these low-probability but high-impact events to ensure the highest safety standards.”

In seeking the most efficient combination of factors, the researchers created full-scale computer-aided design models of the A320 cabin and used Pathfinder — the industry-standard software for evacuation modeling — to simulate passengers’ behavior. They found the proportion and location of elderly passengers have the largest effect on evacuation time.

The fastest option — a layout that accommodates a total of 152 passengers with two rows of first-class seats at the front, and 30 elderly passengers evenly distributed throughout the cabin — still required 141 seconds for all the passengers to reach the ground, much longer than the FAA mandates.

Previous studies have shown that cognitive decline in elderly populations can affect situational awareness and delay decision making, and that reduced dexterity can be exacerbated during high-stress situations. The researchers hope that incorporating this information into their findings — for example, by offering additional safety briefings to elderly passengers — will help further accelerate the deboarding process.

Children, infants, and pregnant women also introduce unique physical capabilities and behaviors that add another vital layer to evacuation modeling, which the group plans to investigate in their future work.

“We hope these findings help airlines proactively mitigate risks,” Zhang said. “By understanding how passenger distribution affects evacuation, airlines could potentially implement more strategic seating arrangements to optimize safety without compromising operational efficiency.”

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The article “Effect of elderly passenger distribution on A320 aircraft evacuation under dual-engine fire scenarios” is authored by Xu Zhao, Ying Xia, Chenyang Zhang, Tianchang Meng, Gaobo Yang, Hua Chen, and Yu Zhang. It will appear in AIP Advances on March 31, 2026 (DOI: 10.1063/5.0310405). After that date, it can be accessed at https://doi.org/10.1063/5.0310405.

ABOUT THE JOURNAL

AIP Advances is an open access journal publishing in all areas of physical sciences — applied, theoretical, and experimental. The inclusive scope of AIP Advances makes it an essential outlet for scientists across the physical sciences. See https://pubs.aip.org/aip/adv.

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Journal

AIP Advances

DOI

10.1063/5.0310405 

Article Title

Effect of elderly passenger distribution on A320 aircraft evacuation under dual-engine fire scenarios

Article Publication Date

31-Mar-2026

 

Getting a glimpse of viral dances in the dark in the Sargasso Sea

Study shows time-based patterns that can inform ocean modeling

Ohio State University

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COLUMBUS, Ohio – In a new study of viral abundance over a short time frame in the Sargasso Sea, researchers found that almost all viruses with cyclical changes in abundance were most active at night – somewhat surprising when the team expected microbial behavior to pick up pace when light was available for photosynthesis.

It turns out the viruses most busy at night were not infecting bacteria that perform photosynthesis, which are among the types of bacteria known to be infected by viruses. Instead, these overnight viral hosts were microbes that focus on consumption of other organic matter because they can’t produce their own food.

The findings reveal another level of complexity of viral interactions with marine bacteria, opening the door to new questions about how these dances in the dark influence ecological services provided by the world’s oceans.

“We still don’t know most of the genes that viruses have and what they do. So it’s elucidating to know that these patterns exist for these viruses and their predicted hosts,” said first study author Alfonso Carrillo, a PhD student in microbiology at The Ohio State University.

The rare look at microbial changes over a short time frame can also be used to inform future models designed to predict how the oceans will respond to warmer, more acidic water – the current conditions in the Sargasso Sea near Bermuda in the Atlantic Ocean.

“To understand how the ocean works as a whole, you can’t exclude the viruses,” Carrillo said. “It’s important to understand how these viruses are behaving, how they’re interacting with host bacteria, and how those interactions change over time. You can’t really make models of how oceans will change unless you know all of these different frameworks.”

The research was published recently in PLOS Biology.

Water samples for the study were taken as part of a long-term initiative called the Bermuda Atlantic Time Series.  

The team sampled water from the surface and in an area called the deep chlorophyll maximum, or DCM, where a lot of microbes that perform photosynthesis are expected to be found. Over the course of 112 hours, they collected surface water every four hours and DCM water every 12 hours.

“We wanted to ask the question, do the viruses change between the depths and do we see any changes with regard to time? We expect it to change because the DCM has higher chlorophyll and there are differences in light, temperature and oxygen compared to surface levels,” Carrillo said.

The composition of the viral communities present in each setting did differ, as expected, and the team then examined viruses that engaged in diel behavior – that is, cyclical changes in abundance within a 24-hour block of time.

Of the over 48,000 virus species collected, almost 3,100 showed diel behavior – and for about 90%, abundance peaked at night instead of during the day.

“This was unexpected because we thought the majority of the viruses that would have this kind of behavior may be performing photosynthesis or targeting bacteria that perform photosynthesis, but that wasn’t the case,” Carrillo said.

Instead, these viruses more active in the dark infected heterotrophic host microbes: those that eat other organisms because they can’t produce their own food.

“That’s interesting to us because it’s something we hadn’t seen before, and it’s something that we can incorporate into future models about how viruses and their hosts might be behaving in the oceans,” he said.

Carrillo works in the lab of Matthew Sullivan, professor of microbiology and civil, environmental and geodetic engineering and director of the Center of Microbiome Science at Ohio State, whose research program focuses on how viruses impact microbiomes in complex ocean, soil and human systems, including pioneering many experimental and bioinformatic approaches to “see” these impacts. Within that context, his lab is investigating how carbon cycling works in the oceans and the role viruses play. 

Better, faster classification of viruses

Though the study of viruses and their functions in the sea, soil and our guts is advancing every day, the extent of what remains unknown about viruses far exceeds what scientists do know. A new analytical tool developed in Sullivan’s lab is helping narrow that gap, using machine learning to establish a rapid classifier of virus samples.

“This tool allows researchers to organize the virosphere, which basically represents all the viruses that we know about,” said first author Benjamin Bolduc, a computational scientist in microbiology. “And that’s actually really important because if you don’t know what viruses are related to other viruses, then it really impacts the kind of knowledge you can glean from whatever area of science that you’re studying.”

The paper was published recently in Nature Biotechnology.

Compared to its earlier versions, the updated tool, called vConTACT3, expands the breadth and depth to which the organization of the virosphere extends in the biological classification of living organisms.

“For decades we’ve been looking at just the species, or just the genera, and that’s important and relevant, but it doesn’t give you any other information,” Bolduc said. The new tool assists researchers in determining relationships at more general levels, such as family, order, class and phylum.

Previous versions of vConTACT also focused only on prokaryotes – archaea and bacteria that lack a nucleus – while vConTACT3 includes viruses that infect eukaryotes, organisms with a membrane-bound nucleus that include all animals, plants and fungi.

Because virus samples collected by researchers are often snippets of these organisms, their genomes are fragmented, and the lack of whole genomes has been a limiting factor in identifying viruses and, by extension, what they do in the environment.

Bolduc applied machine learning techniques at various stages of the development pipeline to identify patterns among genome fragments, which “helps overcome the fact you don’t necessarily need the whole genome anymore in order to accurately classify a virus,” he said.

The team assessed vConTACT3’s performance against reference datasets and large databases of viral genome sequences.

“The tool is a big deal, increasing what virologists use to understand what new virus was discovered, and does so using knowledge-guided AI with some 60 million sensitivity analyses evaluated to fine tune it,” Sullivan said. “It’s also orders of magnitude faster than its predecessors at processing large datasets.”

Both studies were supported by the U.S. National Science Foundation. Carrillo’s work was also supported by the National Institutes of Health; Montgomery County, Maryland; and the University of Maryland. Bolduc’s work was also supported by the German Research Foundation, the Alexander Humboldt Foundation and the Biotechnology and Biological Sciences Research Council.

Sullivan was the senior author of both studies. Co-authors of the PLOS Biology paper included Emily Hageman, Anna Mackey, Kimberley Ndlovu, Funing Tian, Dean Vik, Christine Sun and Richard Pavan of Ohio State; Lauren Chittick of Midwestern University; Naomi Gilbert of Lawrence Livermore National Laboratory; Daniel Muratore of Georgia Institute of Technology; Gary LeCleir and Steven Wilhelm of the University of Tennessee Knoxville; Ho Jang of Korea Virus Research Institute; and Joshua Weitz of the University of Maryland. Co-authors of the Nature Microbiology paper were Olivier Zablocki and Jiarong Guo of Ohio State; Dann Turner of University of the West of England; Ho Jang of Korea Virus Research Institute; Evelien Adriaenssens of the Quadrum Institute; and Bas Dutilh of Freidrich Schiller University.

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Journal

PLOS Biology

DOI

10.1371/journal.pbio.3003474 

Article Title

Sub-daily virus sampling at the Bermuda Atlantic Time Series reveals diel and depth-structured population dynamics without community-level shifts

 

New vaccine strategy could help extend immunity against evolving viruses

UW–Madison research identifies a way to program longer-lasting T cells, a potential step toward broader, more durable protection against infections like the flu and COVID-19.

University of Wisconsin-Madison

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Researchers at the University of Wisconsin School of Veterinary Medicine have identified a possible way to make longer lasting vaccines for respiratory viruses like influenza and the coronavirus that causes COVID-19.

The work, published March 25 in in the journal Cell Reports, focuses on T cells, a type of immune cell that helps control infections by killing virus-infected cells. Unlike antibodies — the basis of most current vaccines, which can lose effectiveness as viruses mutate — T cells recognize more stable parts of viruses, offering a path to broader protection.

A problem with designing vaccines around T cells, though, is their relatively short lifespan. The new research sheds light on a surprising potential workaround.

“We have discovered essentially a mechanism which we can target — a new clue to generating long-lived T cells,” says M. Suresh, a professor in the Department of Pathobiological Sciences who led the study. 

Rethinking how vaccines trigger immunity

Most vaccines are designed to stimulate antibodies that block infection. That approach works well for many infectious diseases, but it can fall short against viruses that evolve quickly.

“So, what do we do? We need a plan B,” says Suresh. 

For viruses like SARS-CoV-2 and seasonal influenza, that plan B has meant regularly updating vaccines to target newer virus variants and encouraging the public to get the latest flu and COVID shots each year. But that strategy has its pitfalls. 

“With the pandemic we went through, people are just tired of getting vaccinated,” Suresh says. Indeed, vaccination rates have been declining in the United States for years. 

The ability to harness T cells could offer a potentially more effective plan B. Rather than preventing infection outright, T cells help limit disease severity and promote early recovery by identifying and destroying infected cells.

“They go and hunt one infected cell at a time and eliminate them,” Suresh says.

Because T cells recognize internal viral proteins that don’t change much over time, they can remain effective even as viruses mutate. 

A key challenge, however, is the durability of protection offered by T cells, especially in the lungs, where respiratory infections take hold.

Suresh’s lab studies a specialized group of immune cells known as tissue-resident memory T cells, which remain in the lungs and airways as a first line of defense. These cells can respond quickly to infection.

“But the problem is they don’t stay very long,” Suresh says. “They die off, and we still don’t know why.”

A different early signal, a different immune outcome

In the new study, which was funded by the National Institutes of Health, Suresh and his colleagues looked at what happens in the first hours after vaccination, when the body’s innate immune system is activated.

Different types of pathogens trigger different early inflammatory signals that “program” memory T cells to recognize and go after infected cells. Suresh’s team asked whether changing those signals could reshape how T cells develop.

Using an experimental vaccine approach in mice, the researchers compared two types of early immune signals: one that mimics a viral infection and another that resembles a bacterial response. The difference was striking.

“When we had a virus-like inflammation, the memory T cells dropped off and we quickly lost protection,” Suresh says. “But when we created a bacterial-like inflammation, the mice developed a different kind of memory T cell which actually persisted longer and protected longer.”

Stem-like cells that adapt when needed

The longer-lasting cells had characteristics similar to stem cells, Suresh says, including the ability to persist and regenerate. 

Even more surprising, those cells were able to adapt when confronted with a virus. When the researchers exposed vaccinated mice to infection, the T cells shifted into a more typical virus-fighting mode.

“They just flipped,” Suresh says. 

That flexibility suggests the T cells could combine durability with the ability to effectively combat a viral infection.

Toward longer-lasting, broader vaccines

The findings offer a potential path toward vaccines that require fewer boosters and provide broader protection across variants.

“The duration of immunity is really, really important,” Suresh says. “Can we vaccinate fewer times, and can shots protect against new strains?”

The research also highlights the importance of delivering immunity where infections occur. For respiratory diseases, that may mean developing vaccines that work in the nose and lungs rather than through injection.

“The best way to immunize against all our respiratory infections is to give through the normal route of infection,” Suresh says.

What comes next

The current study was conducted in mice. The team plans to test the approach in nonhuman primates and in models that better reflect the diversity of human immune systems.

Future work will also explore ways to guide immune cells to the lungs after traditional vaccination — a strategy that could improve protection without requiring new delivery methods.

This research received funding from the National Institutes of Health (U01 AI124299 and R21 AI149793). 

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Journal

Cell Reports

DOI

10.1016/j.celrep.2026.117197 

Method of Research

Experimental study

Subject of Research

Cells

Article Title

Innate imprinting of transcriptional trajectories governs respiratory TRM fate and persistence

 

Why teens are more self-serving than adults in social situations

Findings provide a first step in understanding the motivations behind cooperation in adolescents and adults, paving the way for future research to explore these behaviours in real-world situations

eLife

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Researchers have found that adolescents focus more on their own interests compared to adults when navigating social dilemmas, even when their interaction partners show greater willingness to cooperate.

The study, published today in as the final Version of Record after appearing previously as a Reviewed Preprint, supports previous findings that teens tend to cooperate less than adults, and sheds new light on how our willingness to work with others chaneLife ges from youth into adulthood. eLife’s editors describe it as important work, with a solid experimental approach to investigate cooperative behaviours in adolescents.

In everyday life, people often need to choose between acting in a way that serves their own interests and cooperating with others. While cooperation can help build positive relationships and reach shared goals, it can also mean giving up some immediate personal gain. 

“Adolescence is a time when young people learn how to navigate friendships and work with others in groups, but research suggests they remain less cooperative at this stage of life. We wanted to build on those findings to understand why this is the case,” says Xiaoyan Wu, who completed her PhD at State Key Laboratory of Cognitive Neuroscience and Learning, and IDG/McGovern Institute for Brain Research, Beijing Normal University, China, and is now a postdoctoral researcher at the University of Zurich, Switzerland. Wu is a co-first author of the study alongside Hongyu Fu, a doctorate student at State Key Laboratory of Cognitive Neuroscience and Learning, and IDG/McGovern Institute for Brain Research.

The team recruited 261 participants to the study: 127 adolescents aged 14–17 years and 134 adults aged 18–30 years. They used a repeated cooperation game called the Prisoner’s Dilemma Game, where each participant was partnered up and placed in a situation where they could either work together for a shared benefit, or try to gain more for themselves at their partner’s expense. The researchers used this approach to see whether the younger participants failed to notice when a partner behaved kindly and in a cooperative manner, or whether they noticed it but were more tempted than adults to take advantage of the situation and gain more for themselves.

They saw, first of all, that teens cooperated less than adults, in line with the previous findings. This lower level of cooperation was not observed generally during the task, but occurred especially after their adult partners had cooperated in previous rounds. They also found that teens and adults were similarly good at estimating how cooperative the other person was – suggesting that adolescents notice when others are willing to work together, but feel less motivated to reciprocate.

The researchers also developed computational models to investigate the dynamic variables guiding participants’ cooperative decision making in the repeated Prisoner’s Dilemma Game. They incorporated both the participants’ expectations of their partner’s cooperation and the reward of reciprocity. Their models revealed that adults cooperated more in response to their partner’s consistent cooperation, while this pattern was absent in adolescents. However, both groups decreased cooperation in response to their partner’s consistent defection, indicating shared responses to non-cooperative behaviour.

“Our findings contribute to an understanding of the developmental aspects of cooperation and the cognitive-affective processes underlying cooperative decision making,” says co-first author Hongyu Fu. “By comparing the cooperative behaviours between adolescents and adults during the game and integrating computational modelling, we share valuable insights into the mechanisms driving cooperative behaviour across different developmental stages.”

The researchers note that there are some limitations to their work. For example, their study involved using artificial opponents with pre-determined cooperation patterns, while it is possible that participants might behave differently in more natural scenarios. Additionally, although participants were recruited from Beijing and nearby regions, minimising regional and cultural variations, they may still differ in their socioeconomic status and social experience. These differences could interact with developmental processes in shaping their cooperative behaviours.

Taking these limitations into account, the authors say their work provides an initial step in understanding cooperation motivations, with the potential for future research to explore these behaviours in more real-world contexts.

“Increasing our understanding of these behaviours could have implications for designing effective interventions to better support teenagers’ social development,” concludes senior author Chao Liu, Professor at State Key Laboratory of Cognitive Neuroscience and Learning, and IDG/McGovern Institute for Brain Research. “Our results suggest that it may help to teach teens to understand others’ intentions, as well as to strengthen how much they value fairness and reciprocate when others are kind and cooperative. It will be interesting for future studies to test whether the patterns we’ve observed also appear in more realistic situations and in more diverse groups of young people.”

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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. In support of our goal, we introduced the eLife Model that ends the accept–reject decision after peer review. Instead, papers invited for review are published as Reviewed Preprints that contain public peer reviews and an eLife Assessment of the significance of the findings being reported and the strength of the evidence. eLife is supported by 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 in eLife, visit https://elifesciences.org/subjects/neuroscience.

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Journal

eLife

DOI

10.7554/eLife.106840.4 

Subject of Research

People

Article Title

The self-interest of adolescents overrules cooperation in social dilemmas

Article Publication Date

31-Mar-2026

 

The ‘thermal hustle’: FIU researchers track how great hammerhead sharks outsmart ocean temperature swings

Florida International University

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FIU researchers are studying how great hammerhead sharks engage in a “thermal hustle,” maintaining peak hunting performance across a wide range of ocean temperatures.

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Credit: Florida International University/Yannis Papastamatiou

Most predators slow down when ocean temperatures shift. Great hammerhead sharks don’t — not significantly anyway.

These ocean predators are masters of the "thermal hustle," maintaining peak hunting performance across a surprisingly wide range of ocean temperatures between winter and summer months, according to new FIU research published this week in the Journal of Experimental Biology. 

Like most ocean animals, great hammerheads have a peak performance water temperature. Theirs is about 84.7 degrees for swimming, hunting and maintaining their normal metabolic function. Like most animals, their performance declines as water temperature changes. However, unlike most other animals, their rate of decline is low. This means they can effectively hunt fast-moving prey like blacktip sharks in winter and fast-moving tarpon and barracuda in summer.

“This tells us that great hammerheads might tolerate changing climates better than other species,” said study co-author Yannis Papastamatiou, FIU associate professor of biological sciences and researcher in the Institute of Environment.

The scientists used advanced biologging technology to track movement, acceleration, depth and water temperature for nine hammerheads in the waters off Florida and the Bahamas. From this data, the team built the first "thermal performance curve,” showing how the sharks’ performance changes across temperatures. They then reviewed historical shark catch data and satellite tag records tracking where hammerheads swim. In spite of their thermal flexibility, great hammerheads were most often found in temperatures close to their preferred 84.7 degrees.

“As ocean temperatures change, hammerheads may shift their range to stay within temperatures where they perform best,” Papastamatiou said. “That could bring them into areas with heavier fishing pressure.”

Thermal performance curve is sometimes used to predict where species will move if oceans warm, but this latest research suggests temperature alone may not be a deciding factor for where great hammerheads are likely to go in the future. Great hammerhead sharks are among the ocean’s most formidable predators, capable of traveling thousands of miles. Yet, they have experienced drastic population declines in the past several decades and are listed as critically endangered by the International Union for Conservation of Nature.

The research was led by FIU alumna Erin Spencer and conducted in collaboration with researchers from Georgia Aquarium, Mote Marine Laboratory and other partners. 

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Journal

Journal of Experimental Biology

DOI

10.1242/jeb.251837 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Thermal performance and activation energy explain flexible thermal habitat use in great hammerhead sharks