Friday, February 14, 2020

Where rural and urban Americans divide on the environment—and where there's common ground

Rural and urban Americans are divided in their views on the environment, but common ground does exist, says a new report led by Duke University's Nicholas Institute for Environmental Policy Solutions.

"The urban/rural divide on the environment is real, but it centers not on differences in how much people value environmental protection but on divergent views toward government regulation," said lead author Robert Bonnie, executive in residence at the Nicholas Institute and a former undersecretary for natural resources and environment at the U.S. Department of Agriculture. "Rural Americans, across party lines, are less supportive of governmental oversight on the environment than their urban/suburban counterparts."

The study was conducted over two years by the Nicholas Institute with assistance from the University of Rhode Island, the University of Wyoming, Hart Research Associates and New Bridge Strategy. It involved extensive outreach to rural constituencies, including a national survey of more than 2,000 registered voters, focus groups with more than 125 rural voters and in-depth interviews with 36 rural leaders.

Rural Americans have an outsized impact on national environmental policy, from strong representation in the halls of Congress to management of vast swaths of lands and watersheds, the authors note.

Polling results indicated broad support for conservation and environmental protection among both rural and urban/suburban voters. The study also found rural voters to be relatively knowledgeable about environmental policies and the potential economic trade-offs that come with them.

"Americans living in rural communities showed a powerful commitment to protecting the environment, motivated in large part by a strong place identity and desire to maintain local environmental resources for future generations," said study co-author Emily Diamond, assistant professor at the University of Rhode Island.

Rural voters significantly diverged from urban and suburban voters over attitudes toward federal regulation, the study found. In the polling, rural voters across political parties expressed more skepticism for government policies. Participants in focus group conversations often voiced strong support for conservation and environmental protection in the abstract but raised concerns about the impacts and effectiveness of specific policies.

Climate change proved to be another dividing line between rural and urban/suburban voters.

"Our focus groups and interviews echoed this sense that rural opposition to climate change policies may be tied to negative experiences they have had with other federal environmental regulations," Diamond said.

"Climate change is a polarizing issue in rural America, but there is a path forward that can win rural support," Bonnie added. "Our study shows that engagement and collaboration with rural stakeholders will be important to winning over rural support."

There is no quick fix to bridging the urban/rural divide on environmental policies, the authors said. They recommend that policymakers, environmentalists and conservation groups engage more with rural communities when developing policies that could affect them. The authors also suggest federal policies—especially for addressing climate change—are more likely to gain rural voters' support if they allow for state and local partnerships and collaboration with rural stakeholders.

Other key recommendations include:

Working with trusted messengers, such as farmers, ranchers, and cooperative extension services, to convey information about environmental policies to local stakeholders
Improving scientific outreach to rural communities
Offering opportunities to address environmental policy priorities in a way that is compatible with rural economiesNew poll shows rural health may be powerful issue in 2020 election

More information: Understanding Rural Attitudes Toward the Environment and Conservation in America, nicholasinstitute.duke.edu/publications/understanding-rural-attitudes-toward-environment-and-conservation-america

Status update: OSIRIS-REx Osprey Flyover

by Nancy Neal Jones, NASA's Goddard Space Flight Center

NASA's OSIRIS-REx spacecraft safely executed a 0.4-mile (620-m) flyover of the backup sample collection site Osprey as part of the mission's Reconnaissance B phase activities. Preliminary telemetry, however, indicates that the OSIRIS-REx Laser Altimeter (OLA) did not operate as expected during the 11-hour event. The OLA instrument was scheduled to provide ranging data to the spacecraft's PolyCam imager, which would allow the camera to focus while imaging the area around the sample collection site. Consequently, the PolyCam images from the flyover are likely out of focus.

The other science instruments, including the MapCam imager, the OSIRIS-REx Thermal Emissions Spectrometer (OTES), and the OSIRIS-REx Visual and InfraRed Spectrometer (OVIRS), all performed nominally during the flyover. These instruments and the spacecraft continue in normal operations in orbit around asteroid Bennu.

The mission team is currently reviewing the available data from the flyover in order to fully assess the OLA instrument. The entire data set from the flyover, including the PolyCam images, will be completely downlinked from the spacecraft next week and will provide additional insight into any impact that the loss of the OLA data may have.

OLA has already completed all of its principal requirements for the OSIRIS-REx mission. Last year, OLA's scans of Bennu's surface were used to create the high-resolution 3D global maps of Bennu's topography that were crucial for selecting the primary and backup sample collection sites last fall.OSIRIS-REx completes closest flyover of sample site nightingale

Provided by NASA's Goddard Space Flight Center

Climate change means longer take-offs and fewer passengers per plane

by Guy Gratton and Paul D Williams, The Conversation

Climate change means longer take-offs and fewer passengers per aeroplane – new study — Credit: Andrew Barker/Shutterstock

The connection between your next flight and climate change is likely clear in your head. More planes emitting greenhouse gases means more global warming. Simple enough, but there's an opposite side that you probably hadn't thought of.

As the local climates at airports around the world have changed in the past few decades, the conditions that pilots have relied on in order to take off safely have changed too. Our new research suggests that higher temperatures and weaker winds are making take-off more difficult. In the long run, this means that airlines are delivering fewer passengers and cargo for the same amount of fuel.

"Climate" essentially means the average weather conditions at any given place. Scientists know this is changing, but not uniformly. While global temperatures have risen by about 1°C on average, some places have warmed by much more already—and others may be getting cooler.

But climate change isn't just about temperature – winds are slowing down and changing direction around the world too. This is a problem for airport runways that were built many years ago to align with the prevailing winds at the time.

Research has predicted that take-off distances will get longer as the climate warms. This is because higher temperatures reduce air density, which the wings and engines need to get airborne. With reduced headwinds, airplanes also need to generate more groundspeed just to get into the air. Once they're up there, they're subject to in-flight turbulence, which is getting worse due to climate change increasing the energy in jet stream winds.

More than 100,000 aircraft regularly take off and land around the world each day. The record so far is 202,157, on June 29 2018. How are all these changes likely to be affecting them? With colleagues in Britain and Greece, we decided to look at what has happened so far.

Running out of runway

We have been recording the weather at ten Greek airports since 1955. For each year, we took the average wind and overnight minimum temperatures, and then plugged that into performance graphs. These are used to calculate the safe runway lengths and airplane weights that are needed to ensure that airlines can carry their passengers safely.

Temperature changes varied a lot between the airports we studied, between a 2°C and 5°C temperature rise over the 62 years we had data for. So did wind. At one airport, the average speed of wind passing down the runway towards the airplane as it took off (known as headwinds) increased by about 25%. At the other extreme, another airport saw average headwinds on the airport's runway fall by 90% over 43 years.

We found that in every case the conditions had changed over the 62 years to make airplane take-off more difficult. Safety regulations ensure that airplanes are never allowed to take off without enough runway, but on the longer runways we studied, the take-off distances necessary to get a large jet plane into the air had increased by about 1.5% every decade, and about 1% for a smaller turboprop airliner.

In airports with shorter runways, aircraft have to reduce weight. This is all worked out before take-off—cargo, passenger numbers and fuel loads are adjusted accordingly. In the most extreme case we studied this meant that planes were taking off with one passenger fewer (or about 40 kilometers worth of fuel less) each year. These airplanes are climbing less steeply after take-off, creating more pollution and noise nuisance on the ground.

We conducted this research in Greece, but other global studies have found similar trends elsewhere in the world. Small airports—such as those on islands off Scotland or in the Caribbean – are likely to suffer the most as the climate continues to change.

That could mean that airlines must reduce the numbers of passengers they carry on flights, or search for ways to lengthen their runways. In some extreme cases, it could become impossible for some airplanes to use some airports altogether. This is another reminder of how rapidly and extensively human actions are transforming the world around us, and how ill equipped we are to deal with the consequences.Dubai airport reports first dip in passenger numbers in 20 years

Provided by The Conversation

Image: Bolivian highland heart

by European Space Agency

For Valentine's Day, we bring you this Copernicus Sentinel-2 image capturing a beautiful heart-shaped geographical formation in the dramatic landscape of the southern highlands of Bolivia.

The highlands are part of the Altiplano, meaning High Plateau, a region that stretches almost 1000 km from Peru to Bolivia. The landscape consists of a series of basins lying about 3500 m above sea level and is the most extensive area of high plateau on Earth, outside Tibet.

This particular area featured here is a transition between the desert in the west and the tropical forest in the east. The heart-shaped formation has been molded by many layers of different geological formations over time. The many streams and rivers visible in this image have also contributed to the shaping of the landscape as we see it today.

This false-color composite image was processed by selecting spectral bands that can be used for classifying geological features—but here the image processing also highlights this lovely heart for today's image.

Sucre, the capital of the Chuquisaca Department, is visible at the top of the image in gray. Designated a UNESCO World Heritage Site, the city lies at an elevation of around 2800 meters above sea level. To the left of Sucre, the Maragua crater can be seen—a popular hiking destination.

Satellites, such as Copernicus Sentinel-2, allow us to capture beautiful images such as these from space, but also to monitor changing places on Earth. Flying 800 km above, satellites take the pulse of our planet by systematically imaging and measuring changes taking place, which is particularly important in regions that are otherwise difficult to access. This allows for informed decisions to be made to help protect our world for future generations and for all citizens that inhabit our beloved Earth.

We send all our love for Valentine's Day from the high plateaus of Bolivia—and hope we continue our celebration of love for Earth every day of the year.

Image: Deforestation in Bolivia

Provided by European Space Agency

Construction professionals believe fire safety training remains 'inadequate' post-Grenfell

by Birmingham City University

A third of construction professionals believe the industry still has 'inadequate' knowledge and training around fire safety in the wake of the Grenfell Tower disaster, new research has found.

A study carried out by Iman Farah Mohamed, a Quantity Surveying student at Birmingham City University, looked at industry views on fire safety following the tragic incident in June 2017, which saw 72 people lose their lives and more than 70 others injured.

It found that most professionals think "knowledge surrounding fire safety in the construction industry" is inadequate, while the majority also believe higher education institutions need to do more to educate construction students on fire safety before they enter the sector.

The research, which surveyed dozens of people working in construction professions and interviewed one expert directly involved with the Grenfell inquiry, also raised concerns around fire evacuation procedures in UK hospitals.

One respondent said:

"Current building regulations are compliant but I'm not sure if they're good enough. Interestingly there are no specific building regulations for mass evacuations and having spoken to fire services, they are frightened about hospital fires as the patients are not always mobile, making evacuation difficult."

The paper, which has been published in the International Journal of Building Pathology and Adaptation, suggests that specific roles should be created dedicated to fire safety, or that existing staff members are given the issue as a key responsibility.

It also recommends that higher education institutions encompass fire safety training in their courses, to ensure the next generation of construction professionals have the skills needed to prevent future disasters from happening.

The report also found that:

There has been an increased awareness of fire safety concerns in the profession since the Grenfell fire
There are concerns that the UK hospitals may struggle to evacuate immobile patients in the event of a fire
Many believe the current fire safety regulations are 'not fit for purpose'
37 percent of those surveyed believe industry knowledge on fire safety is 'inadequate'
Only 28 percent of respondents believe university curricula provide sufficient education on fire-proofing buildings
50 percent thought communication between residents and constructors around fire safety should be formalized
New roles should be created to prioritise fire safety or this responsibility should be a requirement of existing jobs such as facilities managers
Respondents were conflicted on whether race and class played a role in allowing the neglect which led to the tragedy at Grenfell.

Responders to the research highlighted concerns with the sector's approach to fire safety in the wake of the Grenfell Tower fire with one saying:

"It is not expected that fire could spread externally as there is a mind-set that fire risk is unlikely outside the facade of the building."

One respondent also challenged higher education institutions to do more and said a focus on driving profits was currently taking precedent over developing the skills needed to keep residents safe:

"Educational institutions have drifted from equipping students with detailed knowledge and they now just focus on making money. Standards of education are now severely compromised as there many students entering the industry without knowledge. This explains the poor selection and compromise on building materials. Gone are the years of durability and safety. It's all money."

Iman Farah Mohamed who wrote the paper said: "The research showed that there remains some concern in the construction industry around the knowledge and training provided in relation to fire safety.

"Grenfell was a major incident which brought the issue to the front of people's minds, but while the awareness in the industry has increased, most professionals want to see more from the sector and higher education providers to prioritize fire safety.

"The recommendations suggest how we can make sure professionals of the future are equipped with the knowledge they need to prevent a tragedy like this in the future, and that regulations and guidelines are updated to add a much needed extra layer of protection."

Recommendations:

Specialist training be made available to workers across the sector
Visiting lecturers and specialist practitioners, such as fire safety engineers, should form part of higher education construction courses
New regulations should be introduced to protect against future disasters based on building materials or practices
Funding should be made available to ensure professionals are equipped with the knowledge they need

Combating combustible cladding hazards

More information: Iman Farah Mohamed et al. An investigation into the construction industry's view on fire prevention in high-rise buildings post Grenfell, International Journal of Building Pathology and Adaptation (2019). DOI: 10.1108/IJBPA-05-2019-0048

Using big data to combat catastrophes

by Earth Institute, Columbia University

Using IRI’s Data Library, the new PRISM project will be able to integrate large data sets from finance, energy, agriculture, ecology, climate and other fields to analyze risk factors for catastrophes. Here are two example maps. The one on the left shows an annual index of bird species abundance by bird conservation region; the one on the right shows a normalized difference vegetation index at a 250-meter resolution, updated every 16 days. Credit: State of the Planet

In March 1989, a tripped circuit in the Hydro-Québec power grid left 6 million people without electricity. A week earlier, an unusually harsh snowstorm had strained the region; the day before, a solar flare and accompanying release of plasma and magnetic field sent a mountain of energy propelling toward Earth at a million miles an hour.

The complex interactions of these interconnected systems—environmental science, space weather and solar activity—pushed the electric power grid to a tipping point that could not be understood within any single one of those systems.

The Predictive Risk Investigation System for Multilayer Dynamic Interconnection Analysis (PRISM), funded by the National Science Foundation, aims to harness data in order to identify risk factors across domains for catastrophic events such as the 1989 blackout, which impacted transportation, food, water, health and finance and racked up costs exceeding $2 billion.

Columbia University's International Research Institute for Climate and Society, part of the Earth Institute, is one of the ten collaborating institutions on the project.

The PRISM team—comprising experts from data science, statistics, computer science, finance, energy, agriculture, ecology, hydrology, climate and space weather—will integrate large data sets across different sectors to improve risk prediction. Such an undertaking requires significant computing and data curation capabilities, something extremely well suited to the IRI's Data Library platform.

"This project brings in datasets from very diverse domains of science that use different ways to describe time and space and that use different file formats," says IRI's Rémi Cousin. "Our Data Library removes such complexities by placing all data in an interoperable framework—one which projects scientists are able to query online to feed into their own analytical programs."

Once the data is incorporated into the Data Library, Cousin and his collaborators will use cutting-edge analysis to identify what they've called critical risk indicators—quantifiable information associated with risk exposure, particularly for potential catastrophes. They'll also employ machine learning to look for anomalies in the data that might lead to new insights.

"We want to focus our attention on these worst-case scenarios and the risks associated with them, and how we might measure their likelihood," said Cornell University's David S. Matteson, who is a principal investigator on the two-year, $2.4 million project.

"Our hope is that by identifying systemically important critical risks—those that tie together different domains and have the biggest spillover potential—we will have the most widespread impact in terms of controlling those risks," Matteson said.

If systems had been in place to recognize the heightened risks caused by the snowstorm and the solar flare, the 1989 power outage may have been averted or at least minimized. Similarly, understanding the ways it affected systems such as health care and transportation could help policy makers plan a more effective response.

The multidisciplinary approach is essential because today's world is composed of highly interconnected and interdependent systems, and no single expert is equipped to identify the signs of risk or the full impact of catastrophes.

The researchers will then focus their efforts on identifying risk interconnections, and systemically important risk indicators across the different domains, in order to both predict potential hazards and to lessen the possible system-wide losses once they've occurred. They plan to examine known risk indicators and apply data science to identify new ones.

"Our goal is ultimately to help create early warning systems for catastrophes and improve preparedness for these devastating events," Cousin said. "We plan to integrate the results of the project and make them publicly accessible via the Data Library."

Explore furtherLikelihood of space super-storms estimated from longest period of magnetic field observations
Provided by Earth Institute, Columbia University

This story is republished courtesy of Earth Institute, Columbia University http://blogs.ei.columbia.edu.

How we're preparing for our fiery future

by Murdoch University

New research is informing how, when and where prescribed burns may be used to mitigate bushfire threats while maintaining our biodiversity.

The reverberations of Australia's recent epic bushfire season will be felt for generations. The Eastern State's drought is as bad as the Federation drought, but it is hotter, which means both elevated bushfire risk and unstoppable fires.

"The bushfire crisis has drawn a big thick line underneath some gaping holes in our knowledge," says Dr. Joe Fontaine, who is leading research to contribute to more effective fire management practices.

"We urgently need to understand how climate change and fire interact to drive changes in ecosystems—this may be individual species, ecosystems, or destabilizing carbon storage."

Dr. Fontaine is looking at the role of prescribed burns to inform better decision making by local and state governments.

"Our research is exploring the consequences of intentional, prescribed burns on our biodiverse vegetation in WA. We're considering when, where, and how often fire should be used to reduce hazard and what the biodiversity trade-offs are under a drying and warming climate."

Dr. Fontaine's research has focussed on banksia woodlands, which are considered fire-prone and have high biodiversity value due to the range of plant species and animals that live within them.

He is partnering with the Department of Biodiversity, Conservation and Attractions to select parts of banksia woodlands, measure their biodiversity, burn them and remeasure them.

Those burns provide insights on what happens to the vegetation and what happens to the fuel loads. Based on that, the team aims to provide recommendations on how varying the frequency of prescribed burns relates to biodiversity and fuel hazard reduction.

"How long do they need between fires to do that? If its warmer and dryer, that's going to slow them down. At what point does it mean you can't have a forest because trees take longer to grow and fires are too regular? How long before forests turn into shrublands? This research is trying to understand that."

The principles of Dr. Fontaine's research can be applied almost anywhere, with particularly strong applications in areas with similar climates, from the eastern states of Australia to Germany, Spain and California.

"What we bring from this corner of the world is our fire is more frequent than other areas, allowing us to research across multiple fire cycles. So, the learnings we can get from here and export to the world have massive implications."

Prescribed burns in Western Australia

Provided by Murdoch University

Effectiveness of travel bans—readily used during infectious disease outbreaks—mostly unknown, study finds

by Jake Ellison, University of Washington

Because of the quick and deadly outbreak in late December of a novel coronavirus in Wuhan, China, now known as COVID-19—infecting tens of thousands and killing hundreds within weeks, while spreading to at least 24 other countries—many governments, including the United States, have banned or significantly restricted travel to and from China.

And while travel bans are frequently used to stop the spread of an emerging infectious disease, a new University of Washington and Johns Hopkins University study of published research found that the effectiveness of travel bans is mostly unknown.

However, said lead author Nicole Errett, a lecturer in the UW Department of Environmental & Occupational Health Sciences in the School of Public Health, that's largely due to the fact that very little research into the effectiveness of travel bans exists.

"Some of the evidence suggests that a travel ban may delay the arrival of an infectious disease in a country by days or weeks. However, there is very little evidence to suggest that a travel ban eliminates the risk of the disease crossing borders in the long term," said Errett, co-director of the ColLABorative on Extreme Event Resilience, a research lab focused on addressing real-world issues relevant to community resilience.

The researchers combed through thousands of published articles in an effort to identify those that directly addressed travel bans used to reduce the geographic impact of the Ebola virus, SARS (Severe Acute Respiratory Syndrome), MERS (Middle East Respiratory Syndrome) and the Zika virus. They did not include studies of influenza viruses, for which travel bans have already been shown to be ineffective in the long term.

In the end, the researchers were able to identify just six studies that fit their criteria. Those six were based on models or simulations, not data from actual bans after they were implemented, to assess the effectiveness of travel bans in controlling outbreaks. Consequently, to improve research in this area, the study authors recommend that research questions, partnerships and study protocols be established ahead of the next outbreak so empirical data can be collected and assessed quickly.

"Travel bans are one of several legal options that governments have drawn on to mitigate a pandemic," said co-author Lainie Rutkow, a professor of health policy and management at Johns Hopkins Bloomberg School of Public Health. "As coronavirus spreads, our study raises the importance of understanding the effectiveness of legal and policy responses intended to protect and promote the public's health."

"When assessing the need for, and validity of, a travel ban, given the limited evidence, it's important to ask if it is the least restrictive measure that still protects the public's health, and even if it is, we should be asking that question repeatedly, and often," said co-author Lauren Sauer, an assistant professor of emergency medicine at Johns Hopkins University's School of Medicine and director of operations with the university's Office of Critical Event Preparedness and Response.

Consequently, the authors write, additional research is "urgently needed" to inform policy decisions, especially in light of the tremendous social, economic and political impacts of their implementation.Taiwan hits out at China virus travel bans

More information: Nicole A. Errett, PhD, MSPH et al, An integrative review of the limited evidence on international travel bans as an emerging infectious disease disaster control measure, Journal of Emergency Management (2020). DOI: 10.5055/jem.2020.0446

Women don't fancy easy-to-seduce men

by Hayley Jarvis, Brunel University

How men play the mating game is fairly well understood. But the psychological tricks and ploys women might use to attract or deceive men are less clear.

Now, for the first time, psychologists have tested the potential for women to use predatory game-playing tactics.

Women, like men, can pick up clues a potential partner might be easy to seduce, manipulate, deceive or pressure into sex.

But unlike men, they don't find these cues that someone is 'easy', immature, intoxicated, or reckless attractive. Instead, women are attracted to good-looking, intelligent and flirty men, psychologists discovered.

"Research has focused almost entirely on men as perpetrators of sexual exploitation and women as victims," said Dr. Lora Adair at Brunel University London.

"But we found women can also figure out men's sexual exploitability based on signs they are drunk or a likely pushover."

From making the most of their looks to taking off rings, lying about their pay, job, or age, both sexes have a stash of strategies to get people into bed under false impressions.

When it comes to relationships, men and women are often after different things. And tricks or lies can get people what they want. Just as men may gain from pretending to be 'in love' with someone who puts commitment before consenting to sex, women may gain by using tricks and cheats to trap a man who's 'taken' or out of their league. For instance, they might pressure or con an attractive, genetically 'fit' married man into sex. That would be exploitative—the woman's winning an evolutionary advantage to the man's cost. He might lose out on chance to chase who he chooses, or face violent comeback from a jealous partner.

Evolutionary psychologist Dr Lora Adair on new research into women's potential to deceive, manipulate or pressure men into sex. Credit: Terrence Tiernan

Evolutionary psychologists wanted to see if women find signs of male sexual exploitability—such as flirtiness, booziness and immaturity—attractive and how they spot them.

Some 151 young heterosexual and bisexual female students at a US university were asked to rate 110 photos of men on how attractive they found them in the short term (casual sex) and long term (committed relationship), and how easy it would be to seduce, pressure, or deceive this man into sex. Each photo was coded for 'exploitability cues' such as being shy, young, sleepy, intoxicated, immature, or reckless.

"We found that women can identify men that would be easier to pressure, deceive, seduce, and/or sexually assault, just as men can identify such women. But unlike men, women do not find these cues attractive," says the study. The cues heterosexual men look to exploit in women are likely different from the ones women would use to exploit men.

"Women aren't attracted to men that seem easy to manipulate or deceive," said Dr. Adair.

"By and large, we find no evidence at all of 'game-playing' or exploitative strategies in women's mating toolbox.

"What are women attracted to? Good health and interest. In short, women are interested in men that seem interested in them. Looking 'easy' isn't sexy, reciprocating her interest is."

He Looks "Easy" and She's Not Into It: Sexual Exploitation Cues and Attraction is published in Evolutionary Behavioral Sciences.Men sometimes act less interested in sex—in order to get it

More information: Lora Adair et al. He looks "easy" and she's not into it: Sexual exploitation cues and attraction., Evolutionary Behavioral Sciences (2020). DOI: 10.1037/ebs0000168

Biologists investigate the role of the largest animal brain cells

by Bayreuth University

Very tough and essential for survival — Zebrafish in an aquarium of the Department of Animal Physiology at the University of Bayreuth. Credit: Wolfram Schulze.

The brains of most fish and amphibian species contain two types of conspicuously large nerve cells. These are the largest cells found in any animal brain. They are called Mauthner cells and trigger lightning-fast escape responses when predators approach. Biologists at the University of Bayreuth have now shown that these cells have unique functions essential for survival, the loss of which cannot be compensated for by other nerve cells. In addition, they have discovered that Mauthner cells remain functional for a long time without their cell bodies (soma). The researchers have published their findings in the journal Proceedings of the National Academy of Sciences.

The new findings contradict the widespread view that vital functions of nervous systems are not dependent on individual cells specifically equipped for the purpose. "For some years now, there has been a tendency in biology to assume that there are only weakly developed hierarchies in animal nervous systems. Therefore, one could basically assume that any vital functions are at least partially taken over by other areas of the nervous system in case of failure of the nerve cells that are primarily responsible for a given function. However, Mauthner cells in fish and amphibians are examples of a strong hierarchical dependence. In our experiments, we were able to show that a loss of these cells leads to a lifelong failure of the escape reflexes they control that can never be compensated for," explains the Bayreuth animal physiologist Prof. Dr. Stefan Schuster, who directed the investigations.

This central function of Mauthner cells was long misunderstood. It was believed that a Mauthner cell was condemned to die without its cell body, the soma, and was therefore non-functional. This assumption led to incorrect interpretations of experiments in which the somata of the Mauthner cells had been removed. Here, rapid escapes were still present and these were erroneously explained by other nerve cells compensating for the supposed failure of the Mauthner cells. But in fact, as the Bayreuth researchers have now shown, Mauthner cells are extraordinarily tough. The structure that is crucial for the transmission of excitation in such a cell, the axon, is able to transmit signals to the nervous system and trigger reflex movements even after the cell body has been removed. Only when an important substructure of the axon—the Axon Initial Segment (AIS) - is missing, does a complete functional failure actually occur.

Using the two-photon microscope in Bayreuth, it is possible to switch off individual nerve cells, observe their condition over several days, and at the same time observe the effects on behavior. Credit: Christian Wißler.
Alexander Hecker M.Sc. and Prof. Dr. Stefan Schuster, Department of Animal Physiology at the University of Bayreuth. Credit: Christian Wißler.
Using the two-photon microscope in Bayreuth, it is possible to switch off individual nerve cells, observe their condition over several days, and at the same time observe the effects on behavior. Credit: Christian Wißler.
Alexander Hecker M.Sc. and Prof. Dr. Stefan Schuster, Department of Animal Physiology at the University of Bayreuth. Credit: Christian Wißler.

"This observation is not really surprising, given the central importance of the Mauthner cells. It is precisely because of their unique function that evolution has ensured that they are able to fulfill important tasks even after relatively severe damage to the cell body," says Alexander Hecker M.Sc., the first author of the new study. With high-precision experiments on fish larvae, which did not result in them being killed, he was able to demonstrate the unusual toughness of these nerve cells.

"Our results show that Mauthner cells deserve more attention in biomedicine. In particular, the structures and mechanisms that maintain important functions in these nerve cells even after serious damage to their cell body should be studied in as much detail as possible. This might provide a valuable starting point for investigations that focus on the maintenance and regeneration of damaged nerve cells," added Schuster.In fighting gut infections, nervous system is key, team finds

More information: Alexander Hecker et al, Removing a single neuron in a vertebrate brain forever abolishes an essential behavior, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.1918578117

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