How a city is organized can create less-biased citizens

The city you live in could be making you, your family, and your friends more unconsciously racist. Or, your city might make you less racist. It depends on how populous, diverse, and segregated your city is, according to a new study that brings together the math of cities with the psychology of how individuals develop unconscious racial biases.

The study, published in the latest issue of Nature Communications, presents data and a mathematical model of exposure and adaptation in social networks that can help explain why there is more unconscious, or implicit, racial bias in some cities than others.

The authors hope that local communities and governments can use the findings to help create more just and equitable cities.

"What I think is most interesting is the implication that there's a piece of systemic racism that has to do with how people learn and the way cities are organized," says psychologist Andrew Stier, an SFI Complexity Postdoctoral Fellow and lead author of the study.

Cities create dense networks of social interaction between people.

Because of the interactions with many different people, we need to be constantly adapting to new situations and learning, explains SFI External Professor Luís Bettencourt(University of Chicago), a co-leader of SFI's Cities, Scaling and Sustainability project and co-author of the study.

To see how racial biases emerge from how U.S. cities are organized, Stier turned to the enormous database of the Implicit Association Test (IAT). In the popular online test, volunteer participants are given a pairing of White or Black faces with positive or negative words and asked to categorize a single face or word.

If they are faster to categorize things when White/good are paired they have a White-good bias and if they are faster to categorize things when Black/good are paired they have a Black-good bias.

"People may feel they are not prejudiced, but can unconsciously have a preference for one group or another, and this is revealed by these tests," Stier says.

The researchers took the average IAT bias scores from approximately 2.7 million individuals in different geographic areas and linked them to racial demographics and population data from the U.S. Census to build a model that accounts for how individuals learn biases through their social networks.

They found that when these networks are larger, more diverse, and less segregated in cities, implicit racial biases decrease.

The results suggest that there are structural reasons why cities help or deter people from becoming less racially biased.

Perhaps the most pronounced reason is the segregation of different racial groups into different neighborhoods.

Related to that is the lack of more cosmopolitan public spaces where a diverse range of people can experience positive interactions with one another.

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EVs that go 1,000 km on a single charge: Gel makes it possible

Futuristic advancements in AI and healthcare stole the limelight at the tech extravaganza Consumer Electronics Show (CES) 2024. However, battery technology is the game-changer at the heart of these innovations, enabling greater power efficiency. Importantly, electric vehicles are where this technology is being applied most intensely. Today's EVs can travel around 700km on a single charge, while researchers are aiming for a 1,000km battery range. Researchers are fervently exploring the use of silicon, known for its high storage capacity, as the anode material in lithium-ion batteries for EVs. However, despite its potential, bringing silicon into practical use remains a puzzle that researchers are still working hard to piece together.

Enter Professor Soojin Park, PhD candidate Minjun Je, and Dr. Hye Bin Son from the Department of Chemistry at Pohang University of Science and Technology (POSTECH). They have cracked the code, developing a pocket-friendly and rock-solid next-generation high-energy-density Li-ion battery system using micro silicon particles and gel polymer electrolytes.

This work was published on the online pages of Advanced Science on the 17th of January.

Employing silicon as a battery material presents challenges: It expands by more than three times during charging and then contracts back to its original size while discharging, significantly impacting battery efficiency.

Utilizing nano-sized silicon (10-9m) partially addresses the issue, but the sophisticated production process is complex and astronomically expensive, making it a challenging budget proposition.

By contrast, micro-sized silicon (10-6m) is superbly practical in terms of cost and energy density.

Yet, the expansion issue of the larger silicon particles becomes more pronounced during battery operation, posing limitations for its use as an anode material.

The research team applied gel polymer electrolytes to develop an economical yet stable silicon-based battery system.

The electrolyte within a lithium-ion battery is a crucial component, facilitating the movement of ions between the cathode and anode.

Unlike conventional liquid electrolytes, gel electrolytes exist in a solid or gel state, characterized by an elastic polymer structure that has better stability than their liquid counterparts do.

The research team employed an electron beam to form covalent linkages between micro-silicon particles and gel electrolytes.

These covalent linkages serve to disperse internal stress caused by volume expansion during lithium-ion battery operation, alleviating the changes in micro silicon volume and enhancing structural stability.

The outcome was remarkable: The battery exhibited stable performance even with micro silicon particles (5μm), which were a hundred times larger than those used in traditional nano-silicon anodes.

Additionally, the silicon-gel electrolyte system developed by the research team exhibited ion conductivity similar to conventional batteries using liquid electrolytes, with an approximate 40% improvement in energy density.

Moreover, the team's system holds significant value due to its straightforward manufacturing process that is ready for immediate application.

Professor Soojin Park stressed: "We used a micro-silicon anode, yet, we have a stable battery. This research brings us closer to a real high-energy-density lithium-ion battery system."

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Gas on the run -- ALMA spots the shadow of a molecular outflow from a quasar when the Universe was less than one billion years old

Theoretical predictions have been confirmed with the discovery of an outflow of molecular gas from a quasar when the Universe was less than a billion years old.

A quasar is a compact region powered by a supermassive black hole located in the center of a massive galaxy.

They are extremely luminous, with a point-like appearance similar to stars, and are extremely distant from Earth.

Owing to their distance and brightness, they provide a peek into conditions of the early Universe, when it was less than 1 billion years old.

A team of researchers led by Assistant Professor Dragan Salak at Hokkaido University, Assistant Professor Takuya Hashimoto at the University of Tsukuba, and Professor Akio Inoue at Waseda University, has discovered the first evidence of suppression of star formation driven by an outflow of molecular gas in a quasar-host galaxy in the early Universe.

Their findings, based on observations they made using the Atacama Large Millimeter/submillimeter Array (ALMA), in Chile, were published in The Astrophysical Journal.

Molecular gas is vital to the formation of stars. As the primary fuel of star formation, the ubiquity and high concentrations of molecular gas within a galaxy would lead to a vast number of stars being formed.

By ejecting this gas into intergalactic space faster than it could be consumed by star formation, molecular outflows effectively suppress the formation of stars in galaxies that host quasars.

"Theoretical work suggests that molecular gas outflows play an important role in the formation and evolution of galaxies from an early age, because they can regulate star formation," Salak explains.

"Quasars are especially energetic sources, so we expected that they may be able to generate powerful outflows."

The quasar the researchers observed, J2054-0005, has a very high redshift -- it and the Earth are apparently moving away from each other very fast.

"J2054-0005 is one of the brightest quasars in the distant Universe, so we decided to target this object as an excellent candidate to study powerful outflows," Hashimoto says.

The researchers used ALMA to observe the outflow of molecular gas from the quasar.

As the only telescope in the world that has the sensitivity and frequency coverage to detect molecular gas outflows in the early Universe, ALMA was key to this study.

Speaking about the method used in the study, Salak comments: "The outflowing molecular (OH) gas was discovered in absorption. This means we did not observe microwave radiation coming directly from the OH molecules; instead, we observed the radiation coming from the bright quasar -- and absorption means that OH molecules happened to absorb a part of the radiation from the quasar. So, it was like revealing the presence of a gas by seeing the 'shadow' it cast in front of the light source."

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Vitamin B12 adaptability in Antarctic algae has implications for climate change, life in the Southern Ocean

Vitamin B12 deficiency in people can cause a slew of health problems and even become fatal. Until now, the same deficiencies were thought to impact certain types of algae, as well. A new study examined the algae Phaeocystis antarctica's (P. antarctica) exposure to a matrix of iron and vitamin B12 conditions. Results show that this algae has the ability to survive without B12, something that computer analysis of genome sequences had incorrectly indicated.

The alga, native to the Southern Ocean, starts as a single-cell that can transform into millimeter scale colonies.

The research published in PNAS, "Flexible B12 ecophysiology of Phaeocystis antarctica due to a fusion B12-independent methionine synthase with widespread homologues," conducted by MIT, WHOI, J.C. Venter Institute, and Scripps Institution of Oceanography (UCSD), found that unlike other keystone polar phytoplankton, P. antarctica can survive with or without vitamin B12.

"Vitamin B12 is really important to the algae's metabolism and because it allows them to make a key amino acid more efficiently," said Makoto Saito, one of the study's co-authors and senior scientist at the Woods Hole Oceanographic Institution (WHOI). "When you can't get vitamin B12, life has ways to make those amino acids more slowly, causing them to grow slower as well. In this case, there's two forms of the enzyme that makes the amino acid methionine, one needing B12, and one that is much slower, but doesn't need B12. This means P. antarctica has the ability to adapt and survive with low B12 availability."

Researchers came to their conclusion by studying P. antarctica's proteins in a lab culture, and also searching for key proteins in field samples.

During their observation, they found the algae to have a B12-independent methionine synthase fusion protein (MetE). The MetE gene isn't new, but was previously believed not to have been possessed by P. antarctica. MetE gives the algae the flexibility to adapt to low vitamin B12 availability.

"This study suggests that the reality is more complex. For most algae, maintaining a flexible metabolism for B12 is beneficial, given how scarce the vitamin's supply is in seawater," said Deepa Rao, lead researcher of the study and former MIT postdoc." Having this flexibility enables them to make essential amino acids, even when they can't obtain enough of the vitamin from the environment. Implying that the classification of algae as B12-requiring or not might be too simplistic"

Antarctica, which lives at the base of the food web, has been thought to be entirely controlled by iron nutrition.

The discovery of the MetE gene also indicates vitamin B12 likely plays a factor.

Because of its presence in P. antarctica, the adaptability of the algae gives it a potential advantage to bloom in the early austral spring when the bacteria that produce B12, are scarcer.

This discovery also has implications for climate change. The Southern Ocean, where P. antarctica is found, plays a significant role in the Earth's carbon cycle.

P. antarctica takes in the CO2 and releases oxygen through photosynthesis.

"As our global climate warms, there's increasing amounts of iron entering the coastal Southern Ocean from melting glaciers," Saito said.

"Predicting what the next limiting thing after iron is important, and B12 appears to be one of them. Climate modelers want to know how much algae is growing in the ocean in order to get predictions right and they've parameterized iron, but haven't included B12 in those models yet."

"We are particularly interested in knowing more about the extent of strain level diversity. It will be interesting to see if B12 independent strains have a competitive advantage in a warmer Southern Ocean," said co-author of the study Andy Allen, a joint professor at the J. Craig Venter Institute and the Scripps Institution of Oceanography at the University of California, San Diego.

"Since there is a cost to B12 independence in terms of metabolic efficiency, an important question is whether or not strains that require B12 might become reliant on B12 producing bacteria."

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World's largest childhood trauma study uncovers brain rewiring

The world's largest brain study of childhood trauma has revealed how it affects development and rewires vital pathways.

The University of Essex study -- led by the Department of Psychology's Dr Megan Klabunde -- uncovered a disruption in neural networks involved in self-focus and problem-solving.

This means under-18s who experienced abuse will likely struggle with emotions, empathy and understanding their bodies.

Difficulties in school caused by memory, hard mental tasks and decision making may also emerge.

Dr Klabunde's cutting-edge research used AI to re-examine hundreds of brain scans and identify patterns.

It is hoped the research will help hone new treatments for children who have endured mistreatment.

This could mean therapists focus on techniques that rewire these centres and rebuild their sense of self.

Dr Klabunde said: "Currently, science-based treatments for childhood trauma primarily focus on addressing the fearful thoughts and avoidance of trauma triggers.

"This is a very important part of trauma treatment. However, our study has revealed that we are only treating one part of the problem.

"Even when a child who has experienced trauma is not thinking about their traumatic experiences, their brains are struggling to process their sensations within their bodies.

"This influences how one thinks and feels about one's 'internal world' and this also influences one's ability to empathise and form relationships."

Dr Klabunde reviewed 14 studies involving more than 580 children for the research published in Biological Psychiatry Cognitive Neuroscience and Neuroimaging.

The paper re-examined functional magnetic resonance imaging (fMRI) scans.

This procedure highlights blood flow in different centres, showing neurological activity.

The study discovered a marked difference in traumatised children's default mode (DMN) and central executive networks (CEN) -- two large scale brain systems.

The DMN and the posterior insula are involved in how people sense their body, the sense of self and their internal reflections.

New studies are finding the DMN plays an important role in most mental health problems -- and may be influenced by experiencing childhood trauma.

The CEN is also more active than in healthy children, which means that children with trauma histories tend to ruminate and relive terrible experiences when triggered.

Dr Klabunde hopes this study will be a springboard to find out more about how trauma affects developing minds.

She said: "Our brain findings indicate that childhood trauma treatments appear to be missing an important piece of the puzzle.

"In addition to preventing avoidance of scary situations and addressing one's thoughts, trauma therapies in children should also address how trauma's impacts on one's body, sense of self, emotional/empathetic processing, and relationships.

"This is important to do so since untreated symptoms will likely contribute to other health and mental health problems throughout the lifespan."

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New species of Jurassic pterosaur discovered on the Isle of Skye

A new species of pterosaur from specimens found on the Isle of Skye, Scotland, has been announced by scientists from the Natural History Museum, University of Bristol, University of Leicester, and University of Liverpool.

The new pterosaur is part of the Darwinoptera clade of pterosaurs.

Its discovery shows that the clade was considerably more diverse than previously thought, and persisted for more than 25 million years, from the late Early Jurassic to the latest Jurassic.

During this period species within the clade spread worldwide.

The discovery underpins a new and more complex model for the early evolution of pterosaurs.

The rarity of Middle Jurassic pterosaur fossils and their incompleteness has previously hampered attempts to understand early pterosaur evolution.

This discovery shows that all principal Jurassic pterosaur clades evolved well before the end of the Early Jurassic, earlier than previously realised.

The discovery also shows that pterosaurs persisted into the latest Jurassic, alongside avialans, the dinosaurs which eventually evolved into modern birds.

The remains consist of a partial skeleton of a single individual, including parts of the shoulders, wings, legs and backbone.

Many of the bones remain completely embedded in rock and can only be studied using CT-scanning.

Professor Paul Barrett, Merit Researcher at the Natural History Museum and senior author on the paper, said: "Ceoptera helps to narrow down the timing of several major events in the evolution of flying reptiles. Its appearance in the Middle Jurassic of the UK was a complete surprise, as most of its close relatives are from China. It shows that the advanced group of flying reptiles to which it belongs appeared earlier than we thought and quickly gained an almost worldwide distribution."

Prof. Barrett and his colleagues described the new species, naming it Ceoptera evansae: Ceoptera from the Scottish gaelic word Cheò, meaning mist (a reference to the common gaelic name for the Isle of Skye Eilean a' Cheò, or Isle of Mist), and the Latin -ptera, meaning wing.

Evansae honours Professor Susan E. Evans, for her years of anatomical and palaeontological research, in particular on the Isle of Skye.

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Astronomers spot 18 black holes gobbling up nearby stars

Star-shredding black holes are everywhere in the sky if you just know how to look for them. That's one message from a new study by MIT scientists, appearing today in the Astrophysical Journal.

The study's authors are reporting the discovery of 18 new tidal disruption events (TDEs) -- extreme instances when a nearby star is tidally drawn into a black hole and ripped to shreds. As the black hole feasts, it gives off an enormous burst of energy across the electromagnetic spectrum.

Astronomers have detected previous tidal disruption events by looking for characteristic bursts in the optical and X-ray bands. To date, these searches have revealed about a dozen star-shredding events in the nearby universe. The MIT team's new TDEs more than double the catalog of known TDEs in the universe.

The researchers spotted these previously "hidden" events by looking in an unconventional band: infrared. In addition to giving off optical and X-ray bursts, TDEs can generate infrared radiation, particularly in "dusty" galaxies, where a central black hole is enshrouded with galactic debris. The dust in these galaxies normally absorbs and obscures optical and X-ray light, and any sign of TDEs in these bands. In the process, the dust also heats up, producing infrared radiation that is detectable. The team found that infrared emissions, therefore, can serve as a sign of tidal disruption events.

By looking in the infrared band, the MIT team picked out many more TDEs, in galaxies where such events were previously hidden. The 18 new events occurred in different types of galaxies, scattered across the sky.

"The majority of these sources don't show up in optical bands," says lead author Megan Masterson, a graduate student in MIT's Kavli Institute for Astrophysics and Space Research. "If you want to understand TDEs as a whole and use them to probe supermassive black hole demographics, you need to look in the infrared band."

Other MIT authors include Kishalay De, Christos Panagiotou, Anna-Christina Eilers, Danielle Frostig, and Robert Simcoe, and MIT assistant professor of physics Erin Kara, along with collaborators from multiple institutions including the Max Planck Institute for Extraterrestrial Physics in Germany.

Heat spike

The team recently detected the closest TDE yet, by searching through infrared observations. The discovery opened a new, infrared-based route by which astronomers can search for actively feeding black holes.

That first detection spurred the group to comb for more TDEs. For their new study, the researchers searched through archival observations taken by NEOWISE -- the renewed version of NASA's Wide-field Infrared Survey Explorer. This satellite telescope launched in 2009 and after a brief hiatus has continued to scan the entire sky for infrared "transients," or brief bursts.

The team looked through the mission's archived observations using an algorithm developed by co-author Kishalay De. This algorithm picks out patterns in infrared emissions that are likely signs of a transient burst of infrared radiation. The team then cross-referenced the flagged transients with a catalog of all known nearby galaxies within 200 megaparsecs, or 600 million light years. They found that infrared transients could be traced to about 1,000 galaxies.

They then zoomed in on the signal of each galaxy's infrared burst to determine whether the signal arose from a source other than a TDE, such as an active galactic nucleus or a supernova. After ruling out these possibilities, the team then analyzed the remaining signals, looking for an infrared pattern that is characteristic of a TDE -- namely, a sharp spike followed by a gradual dip, reflecting a process by which a black hole, in ripping apart a star, suddenly heats up the surrounding dust to about 1,000 kelvins before gradually cooling down.

This analysis revealed 18 "clean" signals of tidal disruption events. The researchers took a survey of the galaxies in which each TDE was found, and saw that they occurred in a range of systems, including dusty galaxies, across the entire sky.

"If you looked up in the sky and saw a bunch of galaxies, the TDEs would occur representatively in all of them," Masteron says. "It's not that they're only occurring in one type of galaxy, as people thought based only on optical and X-ray searches."

"It is now possible to peer through the dust and complete the census of nearby TDEs," says Edo Berger, professor of astronomy at Harvard University, who was not involved with the study. "A particularly exciting aspect of this work is the potential of follow-up studies with large infrared surveys, and I'm excited to see what discoveries they will yield."

A dusty solution

The team's discoveries help to resolve some major questions in the study of tidal disruption events. For instance, prior to this work, astronomers had mostly seen TDEs in one type of galaxy -- a "post-starburst" system that had previously been a star-forming factory, but has since settled. This galaxy type is rare, and astronomers were puzzled as to why TDEs seemed to be popping up only in these rarer systems. It so happens that these systems are also relatively devoid of dust, making a TDE's optical or X-ray emissions naturally easier to detect.

Now, by looking in the infrared band, astronomers are able to see TDEs in many more galaxies. The team's new results show that black holes can devour stars in a range of galaxies, not only post-starburst systems.

The findings also resolve a "missing energy" problem. Physicists have theoretically predicted that TDEs should radiate more energy than what has been actually observed. But the MIT team now say that dust may explain the discrepancy. They found that if a TDE occurs in a dusty galaxy, the dust itself could absorb not only optical and X-ray emissions but also extreme ultraviolet radiation, in an amount equivalent to the presumed "missing energy."

The 18 new detections also are helping astronomers estimate the rate at which TDEs occur in a given galaxy. When they figure the new TDEs in with previous detections, they estimate a galaxy experiences a tidal disruption event once every 50,000 years. This rate comes closer to physicists' theoretical predictions. With more infrared observations, the team hopes to resolve the rate of TDEs, and the properties of the black holes that power them.

"People were coming up with very exotic solutions to these puzzles, and now we've come to the point where we can resolve all of them," Kara says. "This gives us confidence that we don't need all this exotic physics to explain what we're seeing. And we have a better handle on the mechanics behind how a star gets ripped apart and gobbled up by a black hole. We're understanding these systems better."

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Increased temperature difference between day and night can affect all life on earth

Researchers from Chalmers University of Technology, in Sweden, have discovered a change in what scientists already knew about global warming dynamics. It had been widely accepted since the 1950s that global temperature rises were not consistent throughout the day and night, with greater nighttime warming being observed. However, the recent study reveals a shift in dynamics: with greater daytime warming taking place since the 1990s. This shift means that the temperature difference between day and night is widening, potentially affecting all life on Earth.

The rise in the global average surface temperature is one of the key characteristics of human-induced climate change.

However, the temperature increase is not uniform throughout the day and night, and nighttime temperatures have increased at a faster pace than daytime temperatures in the latter half of the twentieth century.

This warming pattern, with variations between day and night is termed "asymmetric warming" and could be due to both human activities and naturally occurring phenomena.

In a new study, published in Nature Communications, an international team of researchers reinvestigated the asymmetric warming phenomenon and found that the pattern has reversed.

Between 1961 and 2020, global daytime warming has accelerated, while the warming rate of nighttime temperature is relatively constant.

This reversed trend in asymmetric warming has led to an increasing temperature difference between day and night.

"We initially aimed to confirm the previously observed phenomenon of nighttime warming surpassing daytime warming. To our surprise, not only had the asymmetric warming trend ceased, but our analyses, based on state-of-the-art observation-based datasets, indicate a complete reversal of this original warming pattern over the past three decades," says Ziqian Zhong, post-doctoral researcher at Chalmers.

Global brightening a potential cause

"A likely explanation to this change is a phenomenon called "global brightening," which has been observed since the late 1980s. It is a result of less cloud cover, which causes more sunlight to reach the Earth's surface, leading to higher daytime temperatures and, as a result, a broader difference between daytime and nighttime temperatures over the recent decades," says Ziqian Zhong.

There is currently significant uncertainty regarding the reasons behind the changes in cloud cover.

The "global brightening" may be attributed to a complex interplay between cloud-free and cloudy atmospheres, as well as the effect of small particles in the atmosphere, known as aerosols.

These aerosols can be derived from natural processes like sea spray and wildfires, but also from human activities like fossil fuel burning, and they can have a profound effect on many aspects of the environment.

Apart from the effects from global brightening, the researchers suggest another reason for the reversed asymmetric warming.

The increase in regional drought events and heatwaves suggests a potential weakening of the cooling effect due to evaporation at the Earth's surface, which would typically result in a faster increase in daytime temperatures.

The researchers found that the majority of land, 81 per cent of the total area, experienced larger nighttime warming from 1961 to 1990.

However, in the subsequent period from 1991 to 2020, a shift occurred, with 70 per cent of the observed land areas experiencing larger daytime warming instead.

Affecting all life on Earth

The larger temperature difference between day and night could potentially affect crop yields, plant growth, animal well-being and human health.

For example, an increased temperature difference between daytime and nighttime is recognised as one of the environmental stressors that could lead to elevated heart rate and blood pressure, consequently increasing cardiac workload and the mortality and morbidity of cardiovascular and respiratory diseases.

"This indicates the need to adjust strategies in different areas affected by temperature variations between day and night, such as agriculture, public health, and forestry management, to address the challenges posed by this climate change," says Ziqian Zhong.

Certain tree species in humid areas might enhance their carbon sequestration capacity due to the increased temperature difference between daytime and nighttime.

However, the increased temperature difference between daytime and nighttime might prove disadvantageous for trees in dry regions, as higher daytime temperatures may increase evaporation, leading to deficiency of soil water and unfavorable conditions for tree growth.

Read more at Science Daily

Ambitious roadmap for circular carbon plastics economy

Researchers from the Oxford Martin Programme on the Future of Plastics, University of Oxford, have outlined ambitious targets to help deliver a sustainable and net zero plastic economy. In a paper published in Nature, the authors argue for a rethinking of the technical, economic, and policy paradigms that have entrenched the status-quo, one of rising carbon emissions and uncontrolled pollution.

Currently the global plastics system results in over 1 gigatonnes per annum (Gt/annum) of carbon dioxide equivalent emissions which is the same as the total combined emissions of Europe's three largest economies (UK, Germany and France). If left unchecked, these emissions could rise to 4-5 Gt/annum with other sources of pollution also causing concern.

Another problem is the lack of effective recycling -- in 2019, only 9% of the world's plastic waste was turned into new products through mechanical recycling.

The majority ended up in landfills or was incinerated, and a significant proportion was mismanaged, ending up polluting terrestrial and marine ecosystems.

The authors analyse the current and future global plastics system, proposing technical, legal, and economic interventions from now until 2050 to allow it to transition to net zero emissions and to reduce other negative environmental impacts.

The study includes a future scenario centred on four targets:

• Reducing future plastics demand by one half, substituting and eliminating over-use of plastic materials and products.
• Changing the way plastics are manufactured to replace fossil fuels as the hydrocarbon source to use only renewably raw materials, including waste biomass and carbon dioxide.
• For plastics which are recoverable, maximising recycling very significantly, targeting 95% recycling of those materials which are retrievable from wastes.
• Integrating plastic manufacturing and recycling with renewable power and minimising all other negative environmental impacts, including of additives.

The authors emphasise the need for concerted action across all four target areas to ensure the global plastics systems curbs its climate impacts and meets UN Sustainable Development Goals.

Charlotte Williams, Professor of Chemistry at the University of Oxford's Department of Chemistry and lead author said:

'We need plastics and polymers, including for future low emission technologies like electric vehicles, wind turbines, and for many essential everyday materials.

Our current global plastics system is completely unsustainable, and we need to be implementing these series of very bold measures at scale, and fast.

This is a solvable problem but it needs coherent and combined action, particularly from chemical manufacturers.'

To successfully transition the plastics system, the authors set out principles to ensure 'smart materials design' and differentiate between plastics which are recoverable and irretrievable after use, noting that there is not a one size fits all solution.

Rather, the authors propose careful use of the design principles to help select the optimum production methods and appropriate use of resources, deliver the required performances, ensure waste management, and minimise broader environmental impacts.

A timeline of technical-economic-policy and legal interventions helps readers focus on the actions needed to reach net zero emissions by 2050.

'The time for action has arrived, we cannot afford to wait any longer,' study co-author Fernando Vidal, Postdoctoral Researcher in Chemistry at POLYMAT in Spain and former Oxford Martin School Fellow on the Future of Plastics concluded.

'We must change our concepts around the way we make, use, and dispose of plastics, otherwise we risk perpetuating this problem.

The upcoming UN Global Plastic Treaty is the opportunity to make a lasting change in the right direction.'

Study co-author Cameron Hepburn, Battcock Professor of Environmental Economics at the Oxford's Smith School of Enterprise and the Environment, said: 'The problem is that plastics, while contributing hugely to global pollution and greenhouse gas emissions, are extraordinarily useful.

Our research finds that creating a circular economy for plastics in order to reduce their negative impacts is possible, but only if we can reduce future demand by half, switch to renewable plastics that aren't made from fossil fuels, recycle 95% of what's left, and minimise environmental impacts at every step of the process.

Read more at Science Daily

Scammed! Animals 'led by the nose' to leave plants alone

University of Sydney researchers have shown it is possible to shield plants from the hungry maws of herbivorous mammals by fooling them with the smell of a variety they typically avoid.

Findings from the study published in Nature Ecology & Evolution show tree seedlings planted next to the decoy smell solution were 20 times less likely to be eaten by animals.

"This is equivalent to the seedlings being surrounded by actual plants that are unpalatable to the herbivore. In most cases it does trick the animals into leaving the plants alone," said PhD student Patrick Finnerty, the study's lead author from the School of Life and Environmental Sciences Behavioural Ecology and Conservation Lab.

"Herbivores cause significant damage to valuable plants in ecological and economically sensitive areas worldwide, but killing the animals to protect the plants can be unethical," he said.

"So, we created artificial odours that mimicked the smell of plant species they naturally avoid, and this gently nudged problematic herbivores away from areas we didn't want them to be.

"Given that many herbivores use plant odour as their primary sense to forage, this method provides a new approach that could be used to help protect valued plants globally, either in conservation work or protecting agricultural crops."

The experiment, conducted in Ku-ring-gai Chase National Park in Sydney, used the swamp wallaby as model herbivore.

The researchers selected an unpalatable shrub in the citrus family, Boronia pinnata, and a palatable canopy species, Eucalyptus punctata, to test the concept.

The study compared using B. pinnata solution and the real plant and found both were equally successful at protecting eucalyptseedlings from being eaten by wallabies.

As part of his doctoral research, Mr Finnerty has also tested the method successfully with African elephants, but that fieldwork does not form part of this research paper.

Previous attempts to use repellent substances, such as chilli oil or motor oil, to control animal consumption of plants have inherent limitations, Mr Finnerty said.

"Animals tend to habituate to these unnatural cues and so deterrent effects are only temporary," he said.

"By contrast, by mimicking the smell of plants herbivore naturally encounter, and avoid in day-to-day foraging, our approach works with the natural motivators of these animals, with herbivores less likely to habituate to these smells."

Researchers took this idea and used solutions that produce these undesired aromas.

"As a management tool to protect palatable plants, our technique offers many advantages over real plants as a repellent," Mr Finnerty said.

"Our approach should be transferable to any mammalian, or potentially invertebrate, herbivore that relies primarily on plant odour information to forage and could protect valued plants globally, such as threatened species."

Current solutions to herbivore-related problems often involve costly and environmentally impactful measures such as lethal control or fencing.

The new research introduces an alternative low-cost, humane strategy based on understanding herbivores' foraging cues, motivations and decisions.

"Plant browsing damage caused by mammalian herbivore populations like deer, elephants and wallabies is a growing global concern," said senior study author Professor Clare McArthur.

"This damage is one of the greatest limiting factors in areas of post-fire recovery and revegetation, destroying more than half the seedlings in these areas. It also threatens endangered plants and causes billions of dollars of damage in forestry and agriculture globally.

Read more at Science Daily