Hidden ‘highways’ connect Brazil’s rainforests

University of Exeter

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An Inga tree (I. affinis) growing alongside a river in the cerrado savanna region of central Brazil

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Credit: RT Pennington

Forests flanking Brazil’s rivers act as “highways” that have allowed tree species to move between the Amazon and Atlantic rainforests for millions of years, new research shows.

The two rainforests are separated by hundreds of miles of dry forest and savanna, where most rainforest trees cannot survive.

Until now, it was thought that tree species only passed between the Amazon and the Atlantic forests during periods long ago when the climate was wetter and much of South America was covered in rainforest.

But the new study – led by the Royal Botanic Garden Edinburgh (RBGE) and the University of Exeter – reveals a different story.

“Rather than tree species being exchanged during specific wetter periods in the past, we found that species have dispersed consistently over time,” said Dr James Nicholls, of RBGE.

“This probably happens slowly, by generations of trees growing along the ‘highways’ provided by rivers that run through Brazil’s dry ecosystems.”

The research team – including scientists from Brazil – studied 164 species of Inga trees, which are common in Latin American rainforests.

By analysing DNA, they reconstructed the trees’ family tree – seeing when each species split from its various ancestors. They then mapped where each species is found, allowing them to examine patterns of movement between the Amazon and Atlantic rainforests.

They found 16-20 “dispersal events” when species arrived in the Atlantic forest from the Amazon, and successfully established themselves. These occurred throughout the evolutionary history of Inga – not just during periods when humid forest covered much of Brazil.

Meanwhile, the study only found one or two occasions when species moved from the Atlantic to the Amazon forest. The researchers think this may reflect the relative size of the forests – with the vast Amazon simply producing more outflow of tree seeds.

The findings highlight the importance of conserving riverside forests – which are protected in Brazilian law.

Professor Toby Pennington, from Exeter’s Department of Geography and the Global Systems Institute, and RGBE, said: “This legal protection – and efforts to preserve these riverside forests – are highly valuable for long-term habitat connectivity.

“The study also tells us something fundamental about the history of the incredible biodiversity of the Atlantic rainforest, which contains about 3,000 more plant species than the Brazilian Amazon.

“Only 20% of the Atlantic rainforest now remains intact.

“In the short term, we need to protect these precious rainforests. In the long term, our study shows that we must also conserve the connections between them.”

The study was funded by the United States National Science Foundation.

The paper, published in the journal Proceedings of the Royal Society B, is entitled: “Continuous colonization of the Atlantic coastal rain forests of South America from Amazônia.”

an Inga tree (I. sessilis) from the Mata Atlantica

Credit

RT Pennington

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Journal

Proceedings of the Royal Society B Biological Sciences

DOI

10.1098/rspb.2024.1559 

Article Title

Continuous colonization of the Atlantic coastal rain forests of South America from Amazônia

Amazonian mangrove forests provide nutrients for the ocean

New study highlights the role of mangrove systems in

global biogeochemical cycles

Peer-Reviewed Publication

Helmholtz Centre for Ocean Research Kiel (GEOMAR)

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Mangrove forests are not only critical carbon sinks and biodiversity hotspots but also play a key role as suppliers of trace elements to the ocean. This is shown by a study conducted by the GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany. For example, mangrove systems along the Amazon coastline release about 8.4 million grams of dissolved neodymium into the ocean each year – 64 percent of the total neodymium input in this region. Similar processes are likely for other essential trace elements, such as iron or manganese, which are crucial for marine ecosystems and the carbon cycle.

“Our research shows that mangroves play a central role in the global cycle of trace elements,” explains Dr Antao Xu, first author of the study from GEOMAR. “They act as biochemical reactors, releasing nutrients and metals into coastal waters through processes such as sediment dissolution and pore water exchange.”

Mangrove Systems as "Nutrient Pumps"

The research team analysed water samples from coastal waters, estuaries and mangrove sediments along the Amazonian coast. Distinct isotopic patterns of neodymium and hafnium were identified, revealing their origin and the interactions between sediments, pore water, and seawater. “Mangroves are not only buffer zones that retain material from land; they are also key players that process and selectively release these substances and micronutrients into the ocean,” says Professor Martin Frank, co-author of the study and head of the research division Ocean Circulation and Climate Dynamics at GEOMAR. This exchange of substances supports coastal food chains.

Globally, mangrove systems contribute between six and nine percent of the total neodymium input to the ocean, according to the researchers. This contribution is comparable to the global input of neodymium from the atmosphere via dust.

Global Importance of Mangrove Conservation

The study’s findings underscore the urgent need to protect these threatened ecosystems. Xu states: “Mangroves sit at the interface between land and sea and provide invaluable services for biodiversity and climate regulation. Their prominent role as a source of trace elements is another compelling reason to prioritise their conservation.”

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Journal

Nature Communications

DOI

10.1038/s43247-024-01989-1 

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

The Amazonian mangrove systems accumulate and release dissolved neodymium and hafnium to the oceans

Article Publication Date

8-Jan-2025

 

Better nurse staffing linked to fewer C-sections

Labor and delivery nurse staffing aligning with national standards can improve maternal outcomes

New York University

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Labor and delivery units that are adequately staffed by nurses have lower cesarean birth rates, according to new research published in the journal Nursing Outlook.

“Our findings highlight how crucial nurse staffing is for optimal maternal outcomes,” said Audrey Lyndon, the Vernice D. Ferguson Professor in Health Equity and executive vice dean at NYU Rory Meyers College of Nursing. 

C-sections account for nearly a third of births in the US and are the most common surgery performed in hospitals. While C-sections can be lifesaving and some are necessary for the health of the mother and child, the surgery carries more risks and a longer recovery than vaginal births and can complicate future pregnancies. 

“If we can safely lower the C-section rate, we are improving outcomes for childbearing people and their families,” added Lyndon, the study’s lead author.

Nurses play an important role during childbirth, providing emotional and physical support at the bedside, monitoring the health of the mother and baby, and administering medication. When hospitals are understaffed, nurses are forced to prioritize tasks that require the most immediate attention at the expense of other care. 

“While nurses intuitively know that having enough nurses to provide the attentive care that mother and babies need and deserve improves outcomes, research has been minimal in linking maternity nurse staffing and patient outcomes,” said Kathleen Rice Simpson, a perinatal clinical nurse specialist at Mercy Hospital St. Louis and study author.

To determine if nurse staffing influences C-section rates, the researchers examined how well maternity units adhere to staffing standards established by the Association of Women's Health, Obstetric and Neonatal Nurses (AWHONN). The evidence-based standards call for one nurse to one birthing person during many parts of labor, two nurses at birth, and one nurse for each mother-newborn pair in the first few hours after birth.

The researchers surveyed 2,786 nurses from 193 hospitals across 23 states about staffing on their maternity units. Their responses, collected in 2018 and 2019, were matched with hospital-level administrative data and rates of C-sections and vaginal births.

Better nurse staffing during labor and birth was linked to lower C-section rates and higher vaginal birth rates, including vaginal births among mothers who had previously had C-sections. C-section rates were 11 percent lower in hospitals with nurse staffing aligned with the national standards.

“Concern about cesarean section rates in the US has been high for many years, and there has been little progress toward improvement. This study points us toward one important solution: aligning labor and delivery nurse staffing with consensus- and expert-developed guidelines,” said Joanne Spetz, director of the Institute for Health Policy Studies at the University of California, San Francisco (UCSF) and a study author.

“We hope our findings will encourage hospitals to see the value in nurse staffing consistent with standards to support healthy outcomes for mothers and babies,” said Simpson.

Hospitals and policymakers often point to increased costs related to both C-sections and nurse staffing. The researchers note that the cost of adequate nurse staffing during labor and birth can be balanced by the savings of avoiding unnecessary C-sections, including shorter hospital stays and fewer complications.

“Nursing care is looked at as a cost center as opposed to a revenue center in hospitals, so it’s often one of the first things cut when hospitals are trying to keep costs in line. But research continues to show that nurse staffing is a key contributor to patient safety across departments,” said Lyndon.

“While increasing nurse staffing during a period of shortage can be challenging, this investment could reduce overall costs by reducing rates of surgical cesarean sections and longer-term adverse outcomes for mothers and babies,” said Spetz.

To hold hospitals accountable, the researchers encourage the Centers for Medicare and Medicaid Services (CMS) to consider establishing regulatory standards for nurse staffing as part of their "Birthing-Friendly" designation for high-quality maternity care. 

Additional study authors include Jason Fletcher of NYU Meyers, Gay Landstrom of Trinity Health in Michigan, and Caryl Gay of UCSF. The research was supported by the Agency for Healthcare Research and Quality (grant R01HS025715).

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Journal

Nursing Outlook

DOI

10.1016/j.outlook.2024.102346 

Subject of Research

People

Article Title

Relationship Between Nurse Staffing during Labor and Cesarean Birth Rates in US Hospitals

Article Publication Date

28-Jan-2025

 

A new process with zero emissions for truly biodegradable plastics

The European project PROMICON issues five policy recommendations to support a new method for the production of sustainable bioplastics from microorganisms

Pensoft Publishers

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PROMICON policy brief

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Credit: PROMICON project

Petrol-based plastics are present in many aspects of our daily lives, from clothing to food packaging. They are often left behind in the environment, where they degrade, breaking into thousands of tiny pieces that harm ecosystems and human health. While biodegradable plastics are seen as a potential solution, their production remains limited, accounting for just 1.3 million tons in 2022 compared to 400 million tons of petrol-based plastics. Many biodegradable plastics also fail to biodegrade efficiently under all environmental conditions such as soil, rivers, and oceans.

In this context, researchers from the Horizon 2020 project PROMICON have developed an innovative method that leverages photosynthetic microorganisms (cyanobacteria) to produce polyhydroxyalkanoates (PHA) – a type of bioplastic that fully degrades in soil, water, and marine environments. PHA is naturally produced by microorganisms, but scaling up its production remains a challenge:

 ‘Commercially produced PHA is nowadays highly energy-intensive and relies heavily on organic raw materials and clean water, which conflicts with the EU’s goals for a circular, sustainable economy. The current production process is far away from the zero emissions neutral carbon strategy.’

– explain the authors of PROMICON’s policy brief. 

The new approach for PHA production proposed by researchers from the Polytechnic University of Catalonia uses sunlight, absorbs CO2, and requires minimal organic resources, creating a truly biodegradable plastic alternative that leaves no microplastic residues.

Find out more about the new method for PHA production here. 

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This project receives funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 101000733. Views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Executive Agency (REA). Neither the EU nor REA can be held responsible for them.

 

Study sheds light on how to encourage condom use among teens

North Carolina State University

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A new meta-analysis evaluating condom use across 249 studies and more than a quarter million U.S. teens finds that simply having knowledge about safer sex practices is not enough to encourage condom use. The analysis suggests teens also need to feel confident about buying and using condoms, they need to plan to use them, and they need to be able to communicate effectively with their partners about condom use.

“Condoms are effective at preventing pregnancy and protecting against sexually transmitted infections, but only about half of sexually active teens in the U.S. used a condom the last time they had sex,” says Laura Widman, corresponding author of the meta-analysis and a professor of psychology at North Carolina State University. “Our goal with this work was to figure out exactly what predicts condom use among teens.

“This is important because sexually transmitted infections are on the rise among teens, and this study will help us understand which aspects of sexual health decision-making should be targeted in sex education programs. For example, our analysis really underscores the importance of effective communication between partners about condom use, which tells us that future programs should prioritize developing this skill set in teens.”

For this meta-analysis, the researchers drew on data from 249 studies published between 2000 and 2024. Collectively, those studies involved 251,713 study participants with a mean age of just over 16. The researchers synthesized the data from those studies using statistical techniques to examine 36 different predictors of condom use. The researchers then conducted a series of analyses designed to identify factors that were most closely associated with condom use.

“We found that having knowledge about safe sex, by itself, was not correlated with condom use across studies,” Widman says. “We know that just giving people knowledge alone is not enough to change their behavior.”

However, the researchers did identify several factors that are associated with condom use.

“Teens who used a condom the first time they had sex were far more likely to use condoms consistently over time,” Widman says. “This underscores the importance of early interventions, before teens have their first sexual experiences.”

Other notable predictors were whether teens planned to use condoms prior to having sex, whether teens were communicating with their partners about condom use, and teens’ confidence in their ability to engage in safer sex. The researchers found that all of these predictors held true across age, gender and sexual orientation.

“This meta-analysis combines more than 20 years of research to help us better understand how teens make decisions in sexual relationships,” Widman says. “The findings highlight the need to boost teens’ interpersonal skills and confidence, and to do so early in their development so they can make the best sexual choices for themselves.”

The paper, “Identifying the Strongest Correlates of Condom Use Among U.S. Adolescents: a Systematic Review and Meta-Analysis,” is published in the journal JAMA Pediatrics. The paper was co-authored by NC State Ph.D. students Jordyn McCrimmon and Aaron Lankster; Julia Brasieiro, a postdoctoral researcher at Florida State University and a Ph.D. graduate of NC State; Reina Evans-Paulson of Innovation Research and Training; Anne Maheux of the University of North Carolina at Chapel Hill; and Claire Stout and Sophia Choukas-Bradley of the University of Pittsburgh.

This research was done with support from the Eunice Kennedy Shriver National Institute of Child Health & Human Development under grant R03 HD105784; the National Institutes of Health under grants F31 MH126763 and F31 HD114366; and the National Science Foundation under grants 1940700 and 2139321.

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Journal

JAMA Pediatrics

DOI

10.1001/jamapediatrics.2024.5594 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Identifying the Strongest Correlates of Condom Use Among US Adolescents

Article Publication Date

27-Jan-2025

 

Young people support the idea of a smokefree generation, according to a new study

University of Nottingham

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Young people broadly welcome the idea of the Government’s smokefree generation policy and see it as a chance to free their generation from harmful addiction, according to a study led by the University of Nottingham.

Smoking tobacco kills more people than any other preventable cause. The UK Government are aiming for fewer than five in 100 people to smoke by 2030, however, one study estimates 127,500 people aged between 18 and 25 currently pick up smoking each year.

The Tobacco and Vapes Bill Committee reports on Thursday 30 January and the Bill will return to the House of Commons for debate and final vote among MPs in the coming months.

If passed, the Bill will stop children who turned 15 last year or younger from ever legally being sold cigarettes or other tobacco products.

A new study, published in Nicotine & Tobacco Research led by Nathan Davies, from the Nottingham Centre for Public Health and Epidemiology, and funded by the National Institute for Health and Care Research (NIHR), set out to find out what young people in England think about changing the law on how old you must be to buy tobacco and e-cigarettes.

Mr Davies said: “Nearly all smokers start smoking when they are young, so if we can prevent people from starting in their youth, they are unlikely to begin in later life. Little was known about what young people think about the proposed smokefree generation policy we wanted to find out if they agreed with it in principle and its implementation.”

 

The researchers held focus groups with participants aged between 12 and 21.  Participants were chosen to include those from areas of different areas and for use of tobacco or e-cigarettes.

The focus groups showed that:

• There was broad support for the smokefree generation. Most young participants welcomed the idea of preventing future tobacco addiction, seeing it as a chance to free their generation from harmful, entrenched habits. Young people had first-hand experience of the harm of tobacco; one 13-year-old girl said, “We were really worried about my mum’s smoking. She said that she was going to try and stop, but she really hasn’t. And it must be difficult because it’s not something that she really talks to us much about.”
•  A small minority raised concerns about freedom of choice or showed apathy towards the policy.
• Young people called for strong enforcement. They believed that the policy’s success depends on strict penalties for retailers selling to underage buyers. They felt that, without well-resourced enforcement of offending retailers, the law wouldn’t be as effective or wouldn’t work at all. Many also asked for licensing conditions to be introduced for tobacco retailers.
• Participants asked for a say in shaping and communicating the policy. They believed involving young people from the start ensures messaging resonates and helps politicians understand real-world tactics used to evade age restrictions. A 17-year-old boy said, ““I think youth involvement is really good and important idea because it’s important that young people feel they are the smokefree generation”.

 

“The study conversations show it is really important that young people are involved in the design and implementation of the smokefree generation,” said Mr Davies. “It is reassuring that the general feeling was support for the policy. Young people want the smokefree generation done properly – and that means the Government giving Trading Standards the resources to enforce it from day one.”

Hazel Cheeseman, Chief Executive of Action on Smoking and Health (ASH), said, “These interviews reinforce survey results which find strong support for the phased-out sale of tobacco among those who the policy will impact. MPs who are anxious that they are curbing the choices of future generations should recognise that ending the sale of tobacco is freeing young people from the risk of life-long addiction and chronic illness. The next generation sees this legislation as a gift not a burden and want to be part of creating a smokefree future for all.”

The full results of the study can be found here.

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Journal

Nicotine & Tobacco Research

DOI

10.1093/ntr/ntae300 

Method of Research

Survey

Subject of Research

People

Article Title

Perceptions of Children and Young People in England on the Smokefree Generation Policy: A Focus Group Study

 

Finding the most efficient carbon-neutral aircraft for your flight

Sustainable aviation doesn't have a one-size-fits-all solution, but an interactive tool can identify the right fit given the flight distance, speed and payload

University of MichiganFacebook

 

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OK, we admit, we're a long way from a carbon-free grid—but when we have one, what's the most efficient way to use that energy to fly planes? This question is explored by an interactive tool built by a team of University of Michigan researchers.

"Aircraft provide a fantastic means to transport people and goods anywhere in the world within a day. We want to keep this capability, but with a lower climate impact," said Joaquim Martins, the Pauline M. Sherman Collegiate Professor of Aerospace Engineering at U-M and co-author of the study published in Progress in Aerospace Sciences.

Sustainable aviation doesn't have a silver bullet, but it does have a bunch of options. Battery-powered motors would be most efficient if it weren't for the weight of the batteries: 85% of the electricity makes it to the aircraft. 

Unfortunately, weight is a big deal. Extra weight demands more lift—the force that holds an aircraft in the air. More lift creates more drag, which demands more thrust, which requires more battery power, which adds weight, and pretty soon the battery is taking up the entire weight formerly allocated to cargo or passengers. As a result, battery power is really best for short hops—metro to regional journeys.

The tool lets users see this and also game out different scenarios. For each combination of range and speed, the researchers pinpointed the least energy-hungry option from four sustainable propulsion systems: e-SAF (synthetic jet fuel produced with carbon captured from the air), battery-electric, hydrogen fuel cell and hydrogen combustion. 

"The tool provides a strategy for thinking about what sustainable aviation should look like. It's not an ultimate answer, but a means to compare and evolve these ideas further," said Eytan Adler, a recent doctoral graduate of aerospace engineering at U-M and first author of the study.

The team defined efficiency as the amount of renewable electricity required to generate the fuel that propels an aircraft on a specified mission, which accounts for both sustainability and cost. Currently, fuel makes up 25%-30% of airlines' operating costs and can even edge up to 40% for flights that cross the Atlantic or Pacific oceans.

Of the fuels, e-SAF is the most compatible with existing aircraft. The synthetic fuel would replace jet fuel, negating the CO2 released in flight with the CO2 captured from the air during synthesis. Battery-electric aircraft work just like electric cars, using batteries to power an electric motor, but require different aircraft designs to accommodate batteries.

The two hydrogen propulsion systems differ from one another in the way that hydrogen reacts with oxygen from the air. Fuel cells produce electricity, which powers an electric motor. Combustion produces heat, which drives a turbine. While hydrogen fuel cells do not produce nitrogen oxides—a major contributor to air pollution—and may be more efficient than hydrogen combustion engines in some cases, they are heavier.

To assess the propulsion systems, the research team developed a methodology to rapidly estimate aircraft energy consumption for a given mission. It incorporates currently available or soon-to-be available technologies, and users can adjust sliders to find out how changes in key properties of these technologies change which aircraft is best for a given flight.

It answers questions like what if the battery could store more energy for the same weight? What if we could store more hydrogen without increasing the weight of the tank? What if fuel cells were more efficient? And it also addresses properties of the propeller, motor, fan and more.

While batteries are limited to about 100 miles with current technology, they could be good for up to 800 miles or so if the "Batt 1K" target of 1000 watt hours per kilogram is reached.

For longer haul flights, hydrogen fuel is the most efficient. Although producing hydrogen with electricity is half as efficient as sending that electricity straight to a battery-electric aircraft, liquid hydrogen is two orders of magnitude lighter—even considering the weight of the tank. Of the two hydrogen propulsion options, combustion uses renewable electricity most efficiently for faster flights over about 300 knots. Fuel cells are best for slower flights because they are more efficient than small combustion engines.

Since e-SAF requires a large amount of energy to produce, only 26% of the electricity makes it to the aircraft in the form of fuel. This prevents the synthetic fuel from outcompeting hydrogen or battery options with the given technology assumptions.

Study: Energy demand comparison for carbon-neutral flight (DOI: 10.1016/j.paerosci.2024.101051)

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Journal

Progress in Aerospace Sciences

DOI

10.1016/j.paerosci.2024.101051