Russian scientists improve 3D printing technology for aerospace composites using oil waste

NATIONAL UNIVERSITY OF SCIENCE AND TECHNOLOGY MISIS

Research News  NEWS RELEASE 25-NOV-2020

 

IMAGE: AVIATION PARTS PRINTED ON A 3D PRINTER FROM NEW METAL POWDERS view more 

CREDIT: SERGEY GNUSKOV/NUST MISIS

Scientists from NUST MISIS have improved the technology of 3D printing from aluminum, having achieved an increase in the hardness of products by 1,5 times. The nanocarbon additive to aluminum powder, which they have developed, obtained from the products of processing associated petroleum gas, will improve the quality of 3D printed aerospace composites. The research results are published in the international scientific journal Composites Communications

Today, the main field of application for aluminum 3D printing is the creation of high-tech parts for the aviation and space industries. The presence of even the slightest defects in printed structures is critical to the safety of the technology being created. According to NUST MISIS scientists, the main risk of such defects is the high porosity of the material, caused, among other reasons, by the qualities of the original aluminum powder. To ensure a uniform and dense microstructure of printed products, scientists from the MISIS Catalis Lab proposed adding carbon nanofibers to the aluminum powder. The use of this modifying additive makes it possible to ensure a low porosity of the material and an increase in its hardness by 1.5 times.

"Changing the chemical and phase composition of the powder for printing by introducing additional components into the main matrix allows improving its properties. In particular, carbon nanofibers have high thermal conductivity, which helps to minimize temperature gradients between printed layers during product synthesis, at the stage of selective laser melting. Thanks to this, the microstructure of the material can be almost completely eliminated from inhomogeneities," said the head of the laboratory, professor at NUST MISIS, Ph.D. Alexander Gromov.

The technology for the synthesis of nanocarbon additives developed by the research team includes methods of chemical deposition, ultrasonic treatment, and IR heat treatment. The used carbon nanofibers must be a by-product of associated petroleum gas processing. During its catalytic decomposition, carbon accumulates in the form of nanofibers on dispersed metal particles of the catalyst. Usually, at present, associated gases are simply burned in the fields, which harms the environment. Therefore, the application of the new method also has a serious environmental significance, -- said Professor Gromov. The study has been carried out jointly with specialists from the Boreskov Institute of Catalysis SB RAS. In the future, the research team plans to determine the optimal conditions for selective laser melting of new composite powders, as well as to develop a technology for post-processing and industrial use of synthesized products.

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Forming beliefs in a world of filter bubbles

Study examines how people deal with diverging information

MAX PLANCK INSTITUTE FOR HUMAN DEVELOPMENT

Research News

 

Why do so many Republicans still believe that the recent US presidential election was fraudulent? Is it possible to reach coronavirus deniers with factual arguments? A study by researchers at the Max Planck Institute for Human Development and the University of Amsterdam provides insights into what it is that stops people from changing their minds. Their findings have been published in the journal Proceedings of the Royal Society of London B.

By talking to other people and observing their behavior, we can learn new things, acquire new skills, and adapt to changing conditions. But what if the information provided by the social environment is inconsistent or contradictory? In a recent study, researchers from the Max Planck Institute for Human Development and the University of Amsterdam have investigated how people deal with information from diverse social sources, and how they use that information to form beliefs. "The internet, in particular, has dramatically changed the structure and dynamics of social interactions. The availablility of social sources is to some extent controlled by algorithms--what we see is biased in favor of our own preferences. At the same time, the internet gives us access to potentially conflicting views," says lead author Lucas Molleman, associate research scientist in the Center for Adaptive Rationality at the Max Planck Institute for Human Development and postdoc at the University of Amsterdam.

The researchers first conducted an experimental study with 95 participants from the United States. Participants completed an adapted version of the Berlin Estimate AdjuStment Task (BEAST), which reliably measures individuals' use of social information. They were shown images of groups of animals and asked to estimate the number of animals. They were then shown the estimates of three other participants and asked to make a second estimate. The more participants adjusted their estimates to those of their peers, the more account they had taken of social information.

Across 30 rounds of the task, the researchers varied the conditions of the study, presenting participants with estimates that deviated to a greater or lesser extent from their own estimate, and that were more or less extreme. The results showed that whether participants integrated information from the social environment in their second estimate depended on whether and how strongly their peers' estimates deviated from each other and from their own estimate. Participants were most likely to adjust their estimates when their peers were in close agreement with each other and their estimates were not too different from the participant's own. Higher variation in peers' estimates reduced their impact on the participant's own judgment. In general, participants gave more weight to their own initial estimate than to their peers' estimates. Overall, three adjustment strategies were identified: (1) sticking to one's original estimate, (2) adopting the estimate of one of the three peers, or (3) compromising between one's original estimate and the peer estimates. The relative frequency of these strategies differed significantly between study conditions. When participants observed a single peer who closely agreed with them, they were more likely to stick to their original estimate or to adopt the estimate of the near peer. When none of the peers were in close agreement with them, participants were more likely to compromise by adjusting their estimate towards, but rarely beyond, that of the nearest peer.

"Our experiment quantifies how people weigh their own prior beliefs and the beliefs of others. In our context, there is actually no reason to assume that one's own estimate is better than anyone else's. But what we see here is an effect known in psychology as 'egocentric discounting' - namely that people put more weight on their own beliefs than on those of others," explains co-author Alan Noveas Tump, postdoc at the Center for Adaptive Rationality of the Max Planck Institute for Human Development. "What's more, our study reveals that this weighting is strongly impacted by the consistency of others' beliefs with one's own: people are more likely to heed information that confirms their own beliefs."

Building on these findings, the researchers developed a model that integrates the observed adjustment strategies and captures that people pay particular attention to social information that confirms their personal judgements. Using simulations, they then investigated how people would behave in real-life situations. For example, they simulated a typical filter bubble, where social information tends to come from like-minded people. They also simulated typical attempts to change people's minds by confronting them with information inconsistent with their own beliefs. Finally, they investigated how people react to being simultaneously exposed to different groups with extreme beliefs. Their simulations suggest that confirmation effects can lead to divergent social information being ignored, filter bubble effects being exacerbated, and people becoming more extreme in their attitudes.

"Although our study was experimental in design, our model helps explain many contemporary phenomena. It shows how the way people process social information can exacerbate filter bubbles on the internet, and why public debates often become polarized as people quickly become impervious to opposing arguments. As interactions increasingly often take place online, people can often find information that confirms their existing beliefs, making them less willing to listen to alternatives," says co-author Wouter van den Bos, adjunct research scientist in the Center for Adaptive Rationality at the Max Planck Institute for Human Development and associate professor at the University of Amsterdam.

In future studies, the researchers want to integrate further aspects of reality into the model to find out, for example, whether it matters whether social information comes from a friend, a stranger, an expert, or someone with the same or different political partisanship. They are also investigating how other people influence individuals' altruistic giving and compliance with social norms.

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The keys to the squirrel's evolutionary success in the face of climate change have been identified

UNIVERSIDAD COMPLUTENSE DE MADRID

Research News

 

Their degree of ecological specialisation --the capacity to inhabit many or few environments-- is the most important factor in the evolutionary success of squirrels in the face of climate change, according to research led by the Complutense University of Madrid (UCM) and the Institute of Geosciences (UCM-CSIC).

"The most climate-restricted species, that is, those that are only present in a very specific environment, are more likely to become extinct due to destruction of their habitat", explained Iris Menéndez, a researcher in the Department of Geodynamics, Stratigraphy and Palaeontology at the UCM and the first author of the article published in Mammal Review.

But precisely for the same reason, she added, they are more likely to generate new species: "As their habitat fragments due to climate change, their populations divide, and if they manage to survive long enough, continued isolation encourages speciation".

However, species that are capable of inhabiting very different climates are less dependent on their environment and are less affected by climate change. Consequently, "these species survive longer, and can persist for millions of years without substantial change", Menéndez indicated.

More evolution in mountainous and terrestrial habitats

This study, in which the University of Alcalá de Henares also participated, has demonstrated that species present in mountainous areas are also more likely to generate new species. During warm cycles, different populations may become isolated in the highlands, eventually becoming distinct species if the situation is sufficiently prolonged.

Other factors also affect the response of squirrels to environmental change. For example, all squirrels were originally arboreal but some lineages subsequently adapted to terrestrial habitats, enabling them to occupy new environments.

The Indo-Malayan region is the area with the highest number of squirrel species, inhabited by some 117 different species. However, analyses show that it is North American ground squirrels which have generated the most species in the shortest period of time. "North America hosts all the chipmunks, prairie dogs and marmots, which spread across the continent occupying its prairies. The explanation for this is that being terrestrial enabled them to exploit new resources and adapt to these new situations", explained the UCM researcher.

Studying how climate changes have affected the evolution of squirrels sheds light on the possible consequences of present-day climate change. The study revealed that those squirrel species most specialised in one type of environment are also the most likely to become extinct.

In particular, for this group of small mammals, if climate change is combined with other factors such as deforestation, the consequences could be devastating. "That could herald the loss of much of the diversity of the squirrel family", the author concluded.

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Phytoplankton disturbed by nanoparticles

Due to its antibacterial properties, nanosilver is used in a wide range of products from textiles to cosmetics; but nanosilver if present at high concentrations also disrupts the metabolism of algae that are essential for the aquatic food web dynamics

UNIVERSITÉ DE GENÈVE

Research News

 

IMAGE: THIS NANOPARTICLE DISRUPTS THE METABOLISM OF ALGAE. view more 

CREDIT: UNIGE/ WEI LIU

Products derived from nanotechnology are efficient and highly sought-after, yet their effects on the environment are still poorly understood. A research team from the University of Geneva (UNIGE), working in collaboration with the University of California at Santa Barbara, have investigated the effects of nanosilver, currently used in almost 450 products for its antibacterial properties, on the algae known as Poterioochromonas malhamensis. The results - published in the journal Scientific Reports - show that nanosilver and its derivative, ionic silver, disturb the alga's entire metabolism. Its membrane becomes more permeable, the cellular reactive oxygen species increases and photosynthesis is less effective. The Swiss-American team was able to demonstrate for the first time the metabolic perturbations induced by nanosilver following its uptake in the food vacuoles of freshwater algae, paving the way for early detection of the metabolic changes before they express themselves physiologically.

The nanosilver is used for its antibacterial properties and is employed in textiles and cosmetics, inter alia. In addition, the agro-food, biomedical and biopharmaceutical industry is interested in it for developing drugs, devices and pesticides. «Since nanosilver is designed to destroy, repel or render harmless noxious organisms such as bacteria, scientists have realised that it might also be harmful to organisms that are crucial to our environment,» begins Vera Slaveykova from the Department F.A. Forel for Environmental and Aquatic Sciences in UNIGE's Faculty of Sciences. To assess the influence of nanotechnology products on phytoplankton and to evaluate the impacts on aquatic environment, the researcher team conducted a study on the alga Poterioochromonas malhamensis as a model phytoplankton species. «The phytoplankton are everywhere, in lakes and oceans," continues Professor Slaveykova. «As a whole, phytoplankton generate almost half of the oxygen we breathe. And they have a second essential role, since they are at the base of the food chain. If they accumulate nanoparticles, these will be integrated into the aquatic food chain».

Multiple disturbances

The study led by Professor Slaveykova shows that treating the algae with nanosilver disrupts the metabolism of the amino acids that are vital for producing cellular proteins, the nucleotide metabolism that is important for genes, and fatty and tricarboxylic acids making up the membranes, as well as the photosynthesis and photorespiration elements.

The study results suggest that the silver ions released by the silver nanoparticles are the main toxicity factor. «The nanosilver is internalised in the algal cells by the phagocytotic mechanism used to supply cells with organic matter,» continues Professor Slaveykova. The study is the first to demonstrate that nanoparticles can follow such internalisation path in a species of phytoplankton. «These measurements were carried out in Geneva by Dr Liu using transmission electron microscopy. This entry mechanism is only known in Poterioochromonas malhamensis; it is still unknown if other phytoplankton species express it,» explains the Geneva researcher.

To finish demonstrating nanosilver's toxicity, the international research team highlighted the fact that metabolic disturbances induce physiological dysfunctions. Professor Slaveykova observed lipid peroxidation leading to membrane permeabilization, increased oxidative stress and less efficient photosynthesis - and, it follows, reduced oxygen production.

An Approach That Needs to Be Implemented

The study underlines the full potential of metabolomics geared towards the molecular basis of the disruptions observed. «It's a fundamental contribution to the field: although the metabolomics approaches are properly in place in medical and pharmaceutical sciences, it's not at all the case for environmental toxicology where phytoplankton metabolomics is still in its infancy. The metabolomics is, therefore, a technique that offers the possibility of early detection of changes induced by a toxin, upstream of more global effects such as the alga growth inhibition and their impact on oxygen production. As it's never easy to demonstrate the relationships between cause and effect in complex environment, it is now essential to use approaches like these.»

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Chia, goji & co. -- BfR consumer monitor special superfoods

Superfoods are part of a healthy diet for approximately half of the population

BFR FEDERAL INSTITUTE FOR RISK ASSESSMENT

Research News

 

The term "superfood" is not legally regulated. Superfoods, however, are often referred to as foods whose ingredients are considered particularly beneficial to health - for example, due to their high content of vitamins or minerals and fibre. Only 8 percent of respondents associate health risks with the consumption of superfoods.

"Superfood products are often not sufficiently investigated to be able to evaluate them from a health perspective," says BfR President Professor Dr. Dr. Andreas Hensel. "A balanced and varied diet remains the best basis for staying healthy. This can be supported by the consumption of imported superfoods just as by the consumption of local fruits and vegetables."

Link to the Consumer Monitor special on superfoods: https://www.bfr.bund.de/cm/364/bfr-consumer-monitor-2020-special-superfoods.pdf

Link to the superfoods A-Z index: https://www.bfr.bund.de/en/a-z_index/superfoods-259079.html

In Germany, 70 percent of the respondents have already heard of the term "superfood". About half see high health benefits in these foods. The main benefits cited are the content of vitamins, a generally positive effect on the body and a strengthening of the immune system. One third of respondents have superfoods on their menu at least once a week. However, almost 40 percent state that they do not consume any superfoods at all.

Compared to local foods, the majority tend to label imported foods, such as chia seeds, goji berries and quinoa, as superfoods. Yet, local foods often provide comparable health benefits. For example, blackcurrants present an alternative to goji berries due to their high content of vitamin C just as linseed, with its high content of proteins and omega-3 fatty acids, shares similarities with the nutritional profile of chia seeds.

About two out of five respondents consider the health benefits of superfoods to be scientifically proven. Just as many assume that superfood products are tested for health safety before they are available in Germany.

This particularly applies to superfoods that were rarely used for consumption in the European Union before 1997 and are, therefore, considered to be novel foods. They have to go through strict approval procedures, including an official health safety assessment. Thus far, this has applied to chia seeds, for example.

However, some superfood products, such as certain food supplements, consist of extracts or preparations of plant-based superfoods, which may contain potentially harmful substances in concentrated form. The lack of standards in extraction procedures or partly insufficient data from studies can make the health risk assessment of these products difficult. For this reason, they cannot be compared to the plant-based superfoods from which they are derived.

Only 8 percent of respondents believe that superfoods can pose health risks. Even though the positive effect of these foods for the health usually takes centre stage, certain ingredients and contaminants can be harmful to health if consumed excessively. In some cases, superfoods can also trigger intolerances or allergic reactions.

More detailed information on the possible health risks of superfoods can be found at: https://www.bfr.bund.de/cm/343/superfoods-super-gut.pdf (in German)

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About the BfR Consumer Monitor

Whether antimicrobial resistance, microplastics, salmonella or aluminium in foods - which health risks do the population know about and what is it that worries them? The BfR Consumer Monitor, a representative population survey that has been conducted regularly since 2014, provides answers to these and other questions. To this end, around 1,000 people living in private households in Germany, and who are at least 14 years old, are interviewed by telephone on behalf of the BfR. Furthermore, the BfR conducts representative surveys on individual topics of particular current interest, such as tattoos, e-cigarettes or superfoods.

About the BfR

The German Federal Institute for Risk Assessment (BfR) is a scientifically independent institution within the portfolio of the Federal Ministry of Food and Agriculture (BMEL) in Germany. It advises the German federal government and German federal states ("Laender") on questions of food, chemical and product safety. The BfR conducts its own research on topics that are closely linked to its assessment tasks.

This text version is a translation of the original German text which is the only legally binding version.

Effect of climate change on infectious diseases unknown to half of the population

UNIVERSITAT AUTONOMA DE BARCELONA

Research News

 

The transmission of specific infectious diseases have been altered by processes linked to climatic and environmental anomalies. An increase in infectious outbreaks is expected to be seen in mild climates due to global warming, and the alterations in climate patterns, such as El Niño, are modifying the presence, density, strength and dynamics of transmission of many viruses and pathogens.

Understanding how climate variability affects the transmission of these diseases is important for both researchers and the general public. Much has been done to raise awareness about climate change in the past years, but there still seems to be a widespread lack of knowledge of the effects climate change has on infectious diseases.

A study published recently in PlosOne and conducted by students from the international master's degree Erasmus Mundus IDOH+ (Infectious Disease and One Health) coordinated by the Université de Tours, the UAB and the Hannover Medical School, reveals that almost half of the population is unaware of the relation between climate change and its effect on infectious diseases.

The research was based on a multinational cross-sectional survey, in which a total of 458 participants from around the world were assessed to discover their knowledge of the effects climate change has on the emergence of infectious diseases.

The results reveal a lack of knowledge among the general public, and with marked differences according to nationality and educational background. A total of 48.9% of the participants had never before considered the effects of climate change on infectious diseases. This percentage falls to 38.4% among those with a solid knowledge of the natural sciences, and rises to 59.2% in those who work in sectors not related to science. Despite this difference, the survey also demonstrated that knowledge and awareness of climate change is unrelated to the educational level of participants, given that scientific dissemination of environmentally-related topics has been highly intensified in the past years.

The large majority of participants (64.6%) were afraid of contracting an infectious disease. In Europe, participants were less afraid (51.7%) than their US (71.4%) and Asian (87.7%) counterparts. With regard to protection measures, the large majority (70.5%) consult the need for vaccines before travelling to a tropical country. In line with this observation, over half of those surveyed (56.1%) were afraid of contracting an infectious disease in a tropical country, although differences were detected according to nationality: in this case, European participants were more afraid (72.0%), when compared to US (41.3%) and Asian participants (37.7%).

According to Max van Wijk, Erasmus Mundus IDOH+ student and one of the authors of the study, "this data can help to establish intervention measures that can raise awareness among the public on issures related to climate change and infectious diseases, within the concept of One Health".

"The study was conducted with an academic objective, but contains original content that can be applied to other scientific studies", explains UAB Department of Animal Health and Anatomy lecturer Marga Martín, one of the programme's coordinators.

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High achievement cultures may kill students' interest in math -- especially for girls

FRONTIERS

Research News

 

A new study in Frontiers in Psychology suggests that high national math achievement combined with societal pressures may contribute to how well girls and boys like math. Past research has shown that achievement-driven cultures frequently correlate with less enthusiasm for learning subjects like math. This study of over 500,000 eighth graders from 50 countries is the first to show that girls appear even more susceptible to this effect, providing insights into how to close this gender gap.

"I think we need to look more critically at the idea that we can judge a country's school system mainly on the achievement level its pupils attain--other important aspects, such as pupils feeling interested in their schoolwork, may get lost in the process," says the author, Prof Kimmo Eriksson of Mälardalen University College and Stockholm University in Sweden. "It seems that cultures that promote high achievement in math may also tend to kill many pupils' interest in math schoolwork and I found that this negative effect of high-achievement culture was stronger among girls than among boys."

Eriksson used the results from the multinational Trends in Mathematics and Science Survey (TIMSS) from 2011 and 2015 to look at trends between math performance and students' interest levels. Although the survey had been performed in prior years, 2011 and 2015 were the first years when the survey included both a math test as well as a questionnaire about the students' interest in what they were learning.

The results showed that girls were significantly less interested in math in countries like Japan, Hong Kong, Sweden and New Zealand. But, surprisingly, the roles were reversed in countries like Oman, Malaysia, Palestine and Kazakhstan, where girls were far more engaged in the subject.

One particularly striking result was that whichever way national interest levels trended, the effect was more pronounced among girls. Eriksson named this effect 'female amplification' and suggests that this may be due to girls' stronger tendency to conform to peer influence.

It is important to note that these findings only imply correlation. Additional research is needed to better understand the underlying factors that cause these differences. But these observations may provide useful guidance for how to promote both math interest as well as achievement for girls and boys. Countries such as Singapore have also shown that it is possible to have both high interest and high performance, and further study of these school systems may help improve teaching methods elsewhere.

"By highlighting how girls' interest in schoolwork is especially sensitive to high-achievement culture, perhaps my work can make researchers and policy-makers recognize and address this challenge: How can schools promote high achievement in mathematics without killing pupils' interest in their schoolwork?" says Eriksson.

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RUDN University mathematicians applied 19th century ideas to modern computerized algebra systems

RUDN UNIVERSITY

Research News

 

IMAGE: A TEAM OF MATHEMATICIANS FROM RUDN UNIVERSITY ADDED NEW SYMBOLIC INTEGRATION FUNCTIONALITY TO THE SAGE COMPUTERIZED ALGEBRA SYSTEM. THE TEAM IMPLEMENTED IDEAS AND METHODS SUGGESTED BY THE GERMAN MATHEMATICIAN KARL... view more 

CREDIT: RUDN UNIVERSITY

A team of mathematicians from RUDN University added new symbolic integration functionality to the Sage computerized algebra system. The team implemented ideas and methods suggested by the German mathematician Karl Weierstrass in the 1870s. The results were published in the Journal of Symbolic Computation.

The first computer program capable of calculating integrals of elementary functions was developed in the late 1950s. By creating it, the developers confirmed that a computer could not only perform simple calculations but was also able to deal with tasks that required a certain degree of 'thinking'. Symbolic integration, i.e. integration that involves letters and abstract symbols instead of numbers, is an example of such a task. At the same time, scientists realized that neither humans nor computers were able to determine whether a given integral can be taken in elementary functions (provided such a human or computer used the methods studied in a university course of analysis and took a finite number of steps). Therefore, in the 1960s mathematicians working on symbolic integrators started to refer to methods that had been suggested by Liouville in the 1830s. From that time on, computer scientists have been tapping into the classic scientific heritage.

The calculation of primitives of algebraic functions is one of the bottlenecks in the process of integrator development. Before World War I, the integration of algebraic functions or Abelian integrals had been considered one of the most important issues in mathematics, but later on, it was forgotten. "Current computer algebra systems are able to fulfill even the most exotic requests of mathematical analysis students, but at the same time, many of these systems fail to recognize integrals in elementary functions. Only several packages allow for the integration of algebraic functions or with Abelian integrals, but their development stopped 15 years ago, and their functionality leaves much to be desired," says Mikhail Malykh, a Doctor of Science in Physics and Mathematics, and an assistant professor at the Department of Applied Informatics and Probability Theory, RUDN University.

One of the theories developed by the German mathematician Karl Weierstrass in the 1870s reduces the calculation of an integral of an algebraic function to finding a given set of known integrals of all three types. The initial integral is represented as a sum of standard integrals (this construction is knowns as the normal representation of an Abelian integral). The team from RUDN University confirmed that this representation is indicative of whether a given integral can be calculated in elementary functions. To confirm their theory, the mathematicians tested them on simple elliptical integrals using a software package that had been created by the team in 2017. The package helps calculate coefficients of the normal form of an integral. In the future, the team plans to conduct similar studies for a wider range of integrals.

"This work is just one step on our way to an ambitious goal: we want to express Weierstrass's theory of Abelian integrals and functions using the language of computer algebra and to implement it in the Sage system, giving researchers from all over the world free access to it," added Mikhail Malykh from RUDN University

IS IT GLUTEN FREE?

New modified wheat could help tackle global food shortage

UNIVERSITY OF YORK

Research News

 

Researchers at the University of York have created a new modified wheat variety that increases grain production by up to 12%.

Wheat is one of the most important food crops in the world, providing 20% of human calories; with ever increasing global food demand, increasing crop yield is critically important.

Wheat breeders work hard to increase yield to meet global demand, but since the 'green revolution' of the 1960s, the rate of yield increase has been slowing and is currently less than 1% per year.

Most improvements have been made by breeding varieties that produce higher numbers of grain, but it should also be possible to increase yield by producing plants with bigger grains. When this has been achieved, however, it is accompanied by a decrease in grain numbers.

Researchers at the University of York have now resolved this issue by directly modifying the growth of the young developing grain by increasing the amount of a protein that controls growth rates in plants.

This resulted in plants that produced grain that are up to 12% bigger than in the conventional variety. In field experiments conducted by their collaborators in Chile, they found that there was no decrease in grain number, resulting in an increase in yield.

Professor Simon McQueen-Mason, from the University of York's Centre for Novel Agricultural Products (CNAP) at the Department of Biology, said: "Experts predict that we need to increase global food production by 50% by 2030 in order to meet demand from population growth. The negative impacts of climate change on crop yields are making this even more challenging. While researchers are working hard to meet this challenge, there remains a lot to do."

"Attempts to increase the yield of wheat have been thwarted by the apparent trade-off between grain size and grain number. We decided to side-step this complex control system by giving a boost to the natural growth system that controls the size of plant tissues.

"We did this by increasing the levels of a protein called expansin, which is a major determinant of growth in plants. We targeted this modification so that it was confined to developing wheat grain, and are delighted by the results."

Research partners at the Universidad Austral de Chile conducted field experiments that demonstrated the effectiveness of the plants under agricultural conditions.

The team are now looking at ways to make this research accessible to farmers and the wider industry to help inform their decisions on crop production.

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The research, in collaboration with Professor Daniel Calderini in Chile and Dr Emma Wallington, at the National Institute of Agricultural Botany, was funded by the BBSRC in the UK and FONDECYT in Chile, and is published in New Phytologist.

In temperate trees, climate-driven increase in carbon capture causes autumn leaves to fall sooner

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE

Research News

 

For decades, scientists have expected that the shedding of leaves from temperate trees will get later and later under ongoing climate change. And early observations supported that idea, as warming caused leaves to stay on the trees later over recent decades, driving increased growing season length that could help to slow the rate of climate change. However, a large-scale study of European trees now suggests that this trend is beginning to change, and in fact, tree leaves may start to fall earlier as the productivity of those trees increases. The results build on growing evidence that plant growth is limited by the ability of tree tissues to use and store carbon. While changes in the growing-season lengths of temperate trees greatly affect global carbon balance, future growing-season trajectories remain highly uncertain because the environmental drivers of autumn leaf senescence are poorly understood. Autumn leaf-shedding at the end of the growing season in temperate regions is an adaptation to stressors, such as freezing temperatures. A common related assumption is that alleviating some of these stressors - as a warmer climate could - would allow leaves to persist longer to fix more atmospheric carbon by photosynthesis. However, the role of photosynthesis in governing the timing of leaf senescence has not been widely tested in trees. To do this, Deborah Zani and colleagues used long-term observations from dominant Central European tree species from 1948 to 2015, and experiments designed to modify carbon uptake by trees, to evaluate related impacts on senescence. Collectively, their data show that increased growing-season productivity in spring and summer due to elevated carbon dioxide, temperature, or light levels can lead to earlier - not later - leaf senescence. This is likely because roots and wood cease to use or store leaf-captured carbon at a point, making leaves costly to keep. The authors used their observations to build a model to improve autumn senescence prediction under a business-as-usual climate scenario. It forecasts the possibility of slight advances, not delays, in autumn leaf-dropping dates over the rest of the century. The results "substantially lower our expectations of the extent to which longer growing seasons will increase seasonal carbon uptake in forests," they write, though the universality of this pattern in other forest types remains unknown. They note an important next avenue of research is implementing such growing-season length constraints in Earth system and vegetation models, which currently do not consider these dynamics when predicting seasonal carbon dioxide uptake of plants. A related Perspective discusses the results in more detail.