Trees in savanna areas of Cerrado produce three times more bark than species in forest areas

The mechanism has resulted from evolution over millions of years to protect the buds that enable plants to survive fire. A study conducted in an environmental protection unit can contribute to strategies for mitigating the effects of climate change

Peer-Reviewed Publication

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO

 

IMAGE: TRANSITION BETWEEN SAVANNA AND FOREST IN CENTRAL PORTION OF CERRADO, CAVALCANTE MUNICIPALITY, GOIÁS STATE. FIRE IS PRESENT IN SAVANNA AREAS AND ABSENT IN FOREST AREAS view more 

CREDIT: MARCO ANTONIO CHIMINAZZO/UNESP

 In tropical regions of the planet, savannas and forests often coexist in the same area and are exposed to the same climate. An example is the Cerrado, a Brazilian biome that includes several types of vegetation, from broad-leaved and sclerophyllous in dense woodland or shrubland (cerrado sensu stricto) to semi-evergreen in closed-canopy forest (cerradão), as well as grassland with scattered shrubs (campo sujo) and even semi-deciduous seasonal forest. 

Areas of cerradão develop in the absence of fire, in both poor and moderately fertile soil (dystrophic to mesotrophic).

This coexistence intrigues botanists and ecologists since savannas and forests are home to different species and have different dynamics and functions. Savannas are dense and highly flammable grasslands that burn fairly frequently, with a direct impact on other types of vegetation. 

Forests, on the other hand, have a broad, mostly continuous canopy that provides shade for undergrowth, bushes and smaller trees, and prevents the growth of flammable grass.

Savanna species evolved over millions of years in the presence of fire and have thick bark to protect them. After burning, they form new branches and leaves from asexual buds called gemmae.

A study conducted at the Santa Bárbara Ecological Station, an environmental protection unit in São Paulo state, investigated how much bark is produced by savanna and forest species in the Cerrado, whether savanna species that produce more bark also protect their gemmae more effectively, and whether generalist species (occurring in both savanna and forest) produce different amounts of bark depending on the environment in which they grow. An article on the study is published in the journal Annals of Botany.

The principal investigator for the study was Alessandra Fidelis, a professor in the Department of Biodiversity at São Paulo State University’s Rio Claro Institute of Biosciences (IBRC-UNESP). 

The first author of the article is Marco Antonio Chiminazzo, a PhD candidate at IBRC-UNESP. 

The other co-authors are Aline Bombo, a postdoctoral fellow at IBRC-UNESP, and Tristan Charles-Dominique, a researcher at the Sorbonne in Paris and the University of Montpellier, both in France. 

“We observed that savanna species produce about three times as much bark as forest species, while generalist species are intermediate, producing more bark in savanna than forest areas. This ability to adjust bark production to the environment is known as phenotypic plasticity and may be a deliberate strategy. We also found that species that produce more bark protect their gemmae and internal tissues better,” Chiminazzo told Agência FAPESP.

“Our study shows that fire is an important factor for savanna-type vegetation in the Cerrado, promoting the woody species that can cope with this disturbance and couldn’t live in shady forest areas.”

The study provides evidence that strongly supports those who advocate the carefully controlled use of fire to manage the savanna areas of the Cerrado. Properly managed fire requires zoning and a timetable. Zoning establishes a mosaic framework within which to burn designated areas rotationally in accordance with the timetable.

“Plant species in the Cerrado have adapted to fire, producing thick bark and strongly protecting their gemmae. These traits, which are the result of a long evolutionary process, enable them to survive fires and regenerate after burning,” said Fidelis, who is Chiminazzo’s thesis advisor.

Remainder

Located in the municipality of Águas de Santa Bárbara, the ecological station where the study was conducted is an important native Cerrado remainder in São Paulo state and contains all the different types of savanna and forest found in the biome. “We sampled shrub and tree species from four different types of vegetation with varying frequencies of burning and light availability. We investigated the amount of bark they produce as they develop and how they protect their gemmae against the effects of fire. We then separated the species according to the environment they prefer to inhabit, forming three groups: savanna specialists, forest specialists and generalists [capable of growing in both],” Chiminazzo said.

Future research should set out to understand how and why certain species can adjust bark production, whereas others cannot, he added. “In the context of climate change and changes in fire regimes, garnering deeper knowledge of these species offers a major opportunity to understand and predict which organisms will be more or less endangered, in accordance with their ability to adapt to varying environmental conditions,” he said.

The study was supported by FAPESP via a Young Investigator Grant awarded to Fidelis. In addition, Chiminazzo received a master’s scholarship and a doctoral scholarship. 

About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.

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JOURNAL

Annals of Botany

ARTICLE TITLE

Bark production of generalist and specialist species across savannas and forests in the Cerrado

Veganism is not health-conscious as such

Study analyses dietary and exercise behaviour of vegans

Peer-Reviewed Publication

MEDICAL UNIVERSITY OF VIENNA

Vegans are considered health-conscious both in the public and in their own perception. Researchers at the Centre for Public Health have now examined the dietary patterns and physical activity behaviour of vegans and found a discrepancy between appearance and reality in many cases. Although many vegans exercise more than the average person, the widespread consumption of industrially processed foods in this group cannot be classified as beneficial to health. The results of the study were recently published in the scientific journal "Nutrients".

The research group led by Maria Wakolbinger and Sandra Haider from MedUni Vienna's Centre for Public Health conducted an online survey of 516 people with an average age of 28 who had been vegan for at least three months when the study began. As the responses to the survey demonstrated, "being vegan is not per se synonymous with being 'healthy'", emphasises study director Maria Wakolbinger. As undisputed as the benefits of a plant-based diet for health are in science in the meantime, the degree of processing of the consumed food has to be taken into account, particularly in this category.

Cake or fruit
Against this background, the research team arrived at the distinction between a "health-conscious" and a "convenience" dietary pattern in the vegan lifestyle. Vegans with a convenience-base diet quality (53 percent) were characterised by a higher consumption of processed fish and meat alternatives, vegan savoury snacks, sauces, cakes and other sweets, convenience foods, fruit juices and refined types of grains. "The negative effects of industrially processed foods on health have now been clearly proven in studies," Maria Wakolbinger emphasises. "For people who primarily consume convenience foods, a 29 per cent higher risk of overall mortality, up to 51 per cent higher risk of overweight or obesity, 29 per cent higher risk of cardiovascular diseases and 74 per cent higher risk of type 2 diabetes mellitus have been scientifically proven".

In contrast to the convenience food group, vegans (47 per cent) who are classified as health-conscious consume more vegetables, fruit, protein and milk alternatives, potatoes, wholemeal products, vegetable oils and fats, and cook more often with fresh ingredients.

The studied vegan population also proved to be heterogeneous with regard to physical activity behaviour: "The physical activity level of vegans is higher overall than that of the average population in Austria. However, as our study illustrated, the health-conscious group is significantly more active than those who belong to the convenience food pattern," explains first author Sandra Haider.

"Pudding Veganism"
In contrast to vegetarianism, veganism is a form of plant-based nutrition in which not only meat but all food and by-products of animal origin are dispensed with. In Austria, approximately two percent of people now follow a vegan diet. The term "pudding vegetarianism" has already become established for variants of the vegetarian diet that are unfavourable to health in which, for example, many sweets are consumed instead of meat. "Accordingly, the convenience dietary pattern we identified could well be called 'pudding veganism'," Maria Wakolbinger and Sandra Haider summarise their study on raising awareness which they want to contribute in view of the booming market for ultra-processed meat and dairy substitutes. Today, vegan meat and milk alternatives generate an annual turnover of 1.7 billion Euros in Europe.

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JOURNAL

Nutrients

DOI

10.3390/nu15081847 

ARTICLE TITLE

The Association between Vegan Dietary Patterns and Physical Activity—A Cross-Sectional Online Survey

ARTICLE PUBLICATION DATE

12-Apr-2023

Living through high inflation increases home ownership

UC San Diego Rady School of Management Study reveals implications of today’s high inflation will have a lasting impact on housing markets

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SAN DIEGO

 

IMAGE: FIGURE 1 view more 

CREDIT: UC SAN DIEGO

People who experience periods of high inflation are more likely to buy a home, according to a new study from the University of California San Diego’s Rady School of Management.

The paper, to be published in The Journal of Finance, uses various sources of data which reveal households that have been exposed to high inflation are more likely to invest in real estate. The study suggests many homeowners buy because they are motivated to protect themselves from possible future price hikes.

The study is the first to reveal that personal experience with inflation is a driver of home ownership.

“We think one reason people choose to buy instead of rent is because they are worried about future inflation, which may drive up both rent and house prices,” said Alex Steiny Wellsjo, study co-author and assistant professor of economics and strategy at the Rady School. “People who have lived through high inflation in the past may expect higher inflation in the future, causing them to wish they were a homeowner. This is especially true if they can finance with a fixed-rate mortgage, further protecting them from future inflation.”

Wellsjo added that the implications of the high inflation people are currently experiencing around the world will have a lasting impact on housing markets.

“Our paper suggests that cohorts living through the current inflationary period will have a higher demand for housing for years to come,” she said.

To find out how people make home ownership decisions, Wellsjo and co-author Ulrike Malmendier, a professor with a joint appointment at the Haas School of Business and economics department at UC Berkeley, conducted a novel survey of 700 homeowners in six European countries (Austria, Germany, Ireland, Italy, Portugal and Spain).

Respondents on the survey were asked: what are good reasons to buy a home, whether they have personally experienced high inflation, whether they were worried about future inflation and whether inflation impacted their own decision to buy a home.

Of those surveyed, 50% indicated that “real estate is a good investment if there is inflation.” People who had lived through high inflation were 21% more likely to be worried about inflation in the future and 74% more likely to say that inflation affected their own decision to buy a home.

The authors also used data from the European Central Bank’s Household Finance and Consumption Survey of 220,000 households across 22 European countries, which revealed that the effects of experienced inflation are large. For example, for the typical household, increasing their inflation experiences from 2% to 5.4%, would increase their likelihood of owning from 65% to 75%.

Households’ exposure to past episodes of higher or lower inflation can help to explain differences in the composition of homeownership both within and across countries.

For example, in Germany and Austria, less than half of households own a home. But 85% or more own in Lithuania, Slovakia and Croatia, countries that have histories of high inflation. Similarly, only 57% own their home in France, which has had more price stability, but 82% do in neighboring Spain—a country with a long history of inflation.

“These households with similar demographics and in similar financial situations make systematically different tenure decisions,” write Wellsjo  and Malmendier. “While financial institutions play an important role, as do house prices, housing supply and demographics, we show that economic histories experienced by potential homeowners and especially inflation experiences, strongly predict investment in housing.”

The effect of personal experiences appears to be powerful and long-lasting enough to influence even the homeownership decisions of immigrants who move to a new housing market and still respond to the inflation exposure they experienced in their home countries.

Using data from the American Community Survey, Wellsjo and Malmendier identified household heads who immigrated to the U.S. from outside the country. They were able to calculate the household’s lifetime inflation experiences during their time in their home country and in the U.S. and how that impacted their purchasing decisions after immigrating. Once again, they find that household heads who experienced higher inflation over their lifetime were more likely to be homeowners.

“We show that the relationship between prior inflation and home purchasing choices is not explained by housing market conditions, nor by indicators of current economic conditions or other economic experiences,” the authors write. “The impacts of experiencing high inflation have a long-lasting effect on home ownership.”

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JOURNAL

The Journal of Finance

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Rent or Buy? In ation Experiences and Homeownership within and across Countries

Gentle method allows for eco-friendly recycling of solar cells

Peer-Reviewed Publication

CHALMERS UNIVERSITY OF TECHNOLOGY

 

IMAGE: THIN-FILM SOLAR CELLS ON ROOF TILES view more 

CREDIT: MIDSUMMER

By using a new method, precious metals can be efficiently recovered from thin-film solar cells. This is shown by new research from Chalmers University of Technology, Sweden. The method is also more environmentally friendly than previous methods of recycling and paves the way for more flexible and highly efficient solar cells.

Today there are two mainstream types of solar cells. The most common is silicon-based and accounts for 90 percent of the market. The other type is called thin-film solar cells which in turn uses three main sub-technologies, one of which is known as CIGS (Copper Indium Gallium Selenide), and consists of a layer of different metals, including indium and silver. Thin-film solar cells are by far the most effective of today's commercially available technologies. They can also be made bendable and adaptable, which means that they can be used in many different areas. The problem is that the demand for indium and silver is high, and increased production is accompanied by a growing amount of production waste, which contains a mixture of valuable metals and hazardous substances. Being able to separate attractive metals from other substances, therefore, becomes extremely valuable, both economically and environmentally, as they can be reused in new products.

“It is crucial to remove any contamination and recycle, so that the material becomes as clean as possible again. Until now, high heat and a large amount of chemicals have been used to succeed, which is an expensive process that is also not environmentally friendly”, says Ioanna Teknetzi, PhD student at the Department of Chemistry and Chemical Engineering, who together with Burcak Ebin and Stellan Holgersson published the new results in the journal Solar Energy Materials and Solar Cells.

Now their research shows that a more environmentally friendly recycling process can have the same outcome.

“We took into account both purity and environmentally friendly recycling conditions and studied how to separate the metals in the thin-film solar cells in acidic solutions through a much ‘kinder’ way of using a method called leaching. We also have to use chemicals, but nowhere near as much as with previous leaching methods. To check the purity of the recovered indium and silver, we also measured the concentrations of possible impurities and saw that optimisation can reduce these”, says Ioanna Teknetzi.

The researchers showed that it is possible to recover 100 percent of the silver and about 85 percent of the indium. The process takes place at room temperature without adding heat.

“It takes one day, which is slightly longer than traditional methods, but with our method, it becomes more cost-effective and better for the environment. Our hopes are that our research can be used as a reference to optimise the recycling process and pave the way for using the method on a larger scale in the future”, says Burcak Ebin.

 

The method

1. The film from the solar cell is analysed with respect to material, chemical composition, particle size and thickness. The solar cell is placed in a container with an acid solution at the desired temperature. Agitation is used to facilitate dissolution of metals in the acid solution. This process is called leaching.

2. Leaching effectiveness and chemical reactions are assessed by analysing samples taken at specific times during the leaching process. The different metals are leached at different times. This means that the process can be stopped before all the metals begin to dissolve, which in turn contributes to achieving higher purity.

3. When the leaching is complete, the desired metals are in the solution in the form of ions and can be easily purified to be reused in the manufacture of new solar cells.

 

More about the study

Valuable metal recycling from thin film CIGS solar cells by leaching under mild conditions has been published in Solar Energy Materials and Solar Cells. The authors are Ioanna Teknetzi, Burcak Ebin and Stellan Holgersson at the Department of Chemistry and Chemical Engineering at Chalmers University of Technology. The study has been carried out at Chalmers Material Analysis Laboratory, CMAL, and the research has received funding from the Swedish Energy Agency.

 

For more information, please contact:

Ioanna Teknetzi, PhD student, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, ioanna.teknetzi@chalmers.se

Dr. Burcak Ebin, researcher, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, +46 31 772 17 29, burcak@chalmers.se

Dr. Stellan Holgersson, researcher, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, +46 31 772 28 02, stehol@chalmers.se

 

 

Caption: Thin-film solar cells are highly efficient and can be made bendable and adaptable, meaning they can be used in a wide range of areas, such as here on roof tiles. Photo of solar cells: Midsummer

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JOURNAL

Solar Energy Materials and Solar Cells

DOI

10.1016/j.solmat.2022.112178 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Valuable metal recycling from thin film CIGS solar cells by leaching under mild conditions

How did the Andes Mountains get so huge? A new geological research method may hold the answer

Peer-Reviewed Publication

UNIVERSITY OF COPENHAGEN - FACULTY OF SCIENCE

 

IMAGE: VALENTINA ESPINOZA AND GIAMPIERO IAFFALDANO view more 

CREDIT: UNIVERSITY OF COPENHAGEN

How did the Andes – the world's longest mountain range – reach its enormous size? This is just one of the geological questions that a new method developed by researchers at the University of Copenhagen may be able to answer. With unprecedented precision, the method allows researchers to estimate how Earth's tectonic plates changed speed over the past millions of years.

The Andes is Earth’s longest above-water mountain range. It spans 8900 kilometres along South America’s western periphery, is up to 700 kilometres wide, and in some places, climb nearly seven kilometres into the sky. But exactly how this colossal mountain range emerged from Earth's interior remains unclear among geologists.

University of Copenhagen researchers come with a new hypothesis. Using a novel method developed by one of the researchers, they closely studied the tectonic plate upon which the range is saddled. Their finding has shed new light on how the Andes came into being.

Tectonic plates cover Earth's surface like massive puzzle pieces. They shift a few centimeters each year, at about the same pace as our nails grow. From time to time, these plates can suddenly speed up or slow down. However, we know little about the fierce forces behind these events. The UCPH researchers arrived at estimates that are more precise than ever, both with regards to how much and how often the plates changed velocity historically.

The researchers' new calculations demonstrate that the South American plate suddenly and spectacularly shifted gears and slowed on two significant occasions over the past 15 million years. And this may have contributed to the widening of the enormous chain. The study’s results have been published in the journal Earth and Planetary Science Letters.

Remarkably, the two sudden slowdowns occurred between periods when the Andean range was under compression and growing rapidly taller:

“In the periods up until the two slowdowns, the plate immediately to the west, the Nazca Plate, plowed into the mountains and compressed them, causing them to grow taller. This result could indicate that part of the preexistent range acted as a brake on both the Nazca and the South-American  plate. As the plates slowed down their speed, the mountains instead grew wider,” explains first author and PhD student Valentina Espinoza of the Department of Geosciences and Natural Resource Management.

Mountains made the plate heavier

According to the new study, the South American plate slowed down by 13% during a period that occurred 10-14 million years ago, and 20% during another period 5-9 million years ago. In geologic time, these are very rapid and abrupt changes. According to the researchers, there are mainly two possible reasons for South America’s sudden slowdowns.

One could, as mentioned, be related to the extension of the Andes, where the pressure relaxed and the mountains grew wider. The researchers' hypothesis is that the interaction between the expansion of the mountains and the lower speed of the plate was due to a phenomenon called delamination. That is, a great deal of unstable material beneath the Andes tore free and sank into the mantle, causing major readjustments in the plate’s configuration.

This process caused the Andes to change shape and grow laterally. It was during these periods that the mountain chain expanded into Chile to the west and Argentina to the east. As the plate accumulated more mountain material and became heavier, the plate’s movement slowed.

"If this explanation is the right one, it tells us a lot about how this huge mountain range came to be. But there is still plenty that we don't know. Why did it get so big? At what speed did it form? How does the mountain range sustain itself? And will it eventually collapse?" says Valentina Espinoza.

According to the researchers, another possible explanation for why the plate slowed is that there was a change in the pattern flow of heat from the Earth's interior, known as convection, that moved up into the uppermost viscous layer of the mantle which tectonic plates float on top of. That change manifested itself as a change in the plate’s movement.

The researchers now have the information and tools to begin testing their hypotheses through modelling and experimentation.

May become a new standard model

The method to calculate the changes of tectonic plate motion builds upon the previous work of associate professor and study co-author Giampiero Iaffaldano and Charles DeMets in 2016. The special thing about the method is that it utilises high-resolution geological data, typically used only to calculate the motion of plates relative to each other. Here, the same data has been used to calculate changes in the motion of plates relative to the planet itself. It provides estimates with unprecedented accuracy. 

After testing the method with a combination of six other tectonic plates, the researchers believe that it could become a new standard method:

"This method can be used for all plates, as long as high-resolution data are available. My hope is that such method will be used to refine historic models of tectonic plates and thereby improve the chance of reconstructing geological phenomena that remain unclear to us," says Giampiero Iaffaldano, who concludes:

"If we can better understand the changes that have occurred in the motions of plates over time, we can have a chance at answering some of the greatest mysteries of our planet and its evolution. We still know so little about, for example: the temperature of Earth's interior, or about when plates began moving. Our method can most likely be used to find pieces for this great big puzzle."

FACT BOX: ABOUT THE METHOD

• Tectonic plates change speed often, but high-resolution data is needed to identify their rapid changes over time spans of less than a couple million years.
   
• One key aspect of the method developed by Giampiero Iaffaldano and Charles DeMets in 2016 differs from others. Typically, high-resolution data is only used to calculate the relative motion of plates, i.e. their motion relative to other plates. Their method uses this same kind of data to calculate the absolute motion of plates, i.e. the movement of plates relative to Earth itself. This results in far more accurate estimates than the ones currently obtained through hotspot volcanic chains.

FACT BOX: ABOUT PLATE TECTONICS

• The theory of plate tectonics, first recognized in the 1960s, states that Earth is covered by an outer shell (the lithosphere), divided into a number of rigid plates that float on top the upper part of Earth's mantle (the asthenosphere).

• Observations show that plates come in all sorts of sizes, from the Pacific plate covering an area of 100 million square meters, to microplates with a hundredth times smaller. Tectonic plates may comprise a continental portion, that can reach up to 350 kilometers thick, and oceanic part, which rarely exceeds 100 kilometers thick.

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JOURNAL

Earth and Planetary Science Letters

DOI

10.1016/j.epsl.2023.118009 

ARTICLE TITLE

Rapid absolute plate motion changes inferred from high-resolution relative spreading reconstructions: A case study focusing on the South America plate and its Atlantic/Pacific neighbors

Infant formulas promise too much

Not all infant formulas are equally nutritious

Peer-Reviewed Publication

NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY

Many infant formulas promise a lot. Several products claim that they help develop the brain, increase immunity and promote children's growth and development, among other things.

Now a research group led by Imperial College London has looked at whether these promises have any substance to them. The article has recently been published in BMJ.

“Most of the claims about the health-giving and nutritional properties of breast milk substitutes seem to be based on little or no evidence,” the research group says.

Claims surrounding these replacement milk products are controversial. They can give the impression that infant formulas are just as good as breast milk, and perhaps even better, without any scientific basis for the claim.

Many breastfeeding mums in Norway

The researchers examined products from 15 countries with different social and economic conditions. Norwegian data are also included.

Norway has a tradition of breastfeeding infants for a long time. Four out of five infants in Norway still receive breast milk when they are six months old, and only two per cent never receive any breast milk (in Norwegian).

“Supportive social arrangements and long parental leave contribute to allowing many mothers in Norway to breastfeed,” says Melanie Rae Simpson, an associate professor at NTNU’s Department of Public Health and Nursing.

Simpson has contributed data to the new survey. She is happy about the social arrangements.

“Strict rules for marketing breast milk substitutes mean that advertising doesn’t influence how long women in Norway breastfeed,” says Simpson.

At the same time, some infant formulas make a lot of promises.

Norwegian claims maybe not so crazy, but could be better

“A relatively high proportion of the products available in Norway include one or more claims about being beneficial for health,” says Simpson.

But that doesn’t necessarily mean that the situation in Norway is that bad.

“With so many women who breastfeed, we don't have as many different types of infant formula in our grocery stores compared to some of the other countries in the study,” she says.

This means that a relatively high proportion of the products in Norway are sold in pharmacies.

“These are basically made for children with special needs,” Simpson points out.

The claims of these products are therefore often linked precisely to the special needs of children, but not always.

Norway has clear legislation to prevent undocumented claims from being used in connection with breast milk substitutes. Nevertheless, the documentation was characterized by the same challenges around transparency, independence from industry and scientific quality that the research group saw in the other countries.

608 out of 757 made claims

The research group examined the websites of the various companies that make infant formula. They also inspected the packaging of the products and checked all the health and nutrition claims against the documentation.

The research group found 41 different ingredients linked to these claims, but several companies also market their products without referring to specific ingredients.

The group tested a total of 757 products, and 608 of them were included at least one of a total of 31 different claims about nutrition and health.

Industry runs its own research

Only 161 of the 608 products referred to scientific research to support their claims. But only a small number, about 14 per cent of the investigations, were clinical investigations carried out on humans.

Of these, the researchers found that 90 per cent had a high risk of biased research. This was either because they had received money from the industry or the research was simply carried out by the industry itself.

Much of the so-called "research" consists of reviews, opinions and other forms of research that do not meet high enough quality requirements, such as research on non-human species.

On average, the products included two claims. But the aggressiveness of the marketing varies greatly, from an average of one claim in Australia to as many as four claims in the USA.

Calls for stricter rules

The research group wants stricter rules, and quickly. This is to better protect users, and to avoid aggressive marketing having unwanted consequences for children’s health.

The researchers are supported by Professor Nigel Rollins from the World Health Organization (WHO). He believes that self-regulation, where the industry itself largely runs the research on product effectiveness, is clearly not good enough. Regulatory authorities in the various countries should therefore consider whether they need to do something to improve conditions.

Products from Norway, Australia, Canada, Germany, India, Italy, Japan, Nigeria, Pakistan, Russia, Saudi Arabia, South Africa, Spain, Great Britain and the USA were included in the study.

Reference: Cheung K Y, Petrou L, Helfer B, Porubayeva E, Dolgikh E, Ali S et al. Health and nutrition claims for infant formula: international cross sectional survey, BMJ 2023; 380 doi:10.1136/bmj-2022-071075

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JOURNAL

BMJ

DOI

10.1136/bmj-2022-071075 

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Health and nutrition claims for infant formula: international cross sectional survey

Adaptations allow Antarctic icefish to see under the sea ice

Peer-Reviewed Publication

SMBE JOURNALS (MOLECULAR BIOLOGY AND EVOLUTION AND GENOME BIOLOGY AND EVOLUTION)

 

IMAGE: THE ARTICLE APPEARS IN A RECENT ISSUE OF MOLECULAR BIOLOGY AND EVOLUTION. THE COVER IMAGE SHOWS HOW ICEFISH RHODOPSIN DISPLAYS KINETIC AND SPECTRAL ADAPTATION TO THE COLD DARK SEAS OF THE ANTARCTIC. view more 

CREDIT: OXFORD UNIVERSITY PRESS

Antarctica may seem like a desolate place, but it is home to some of the most unique lifeforms on the planet. Despite the fact that land temperatures average around -60°C and ocean temperatures hover near the freezing point of saltwater (-1.9°C), a number of species thrive in this frigid habitat. Antarctic icefishes (Cryonotothenioidea) are a prime example, exhibiting remarkable adaptations that allow them to survive in the icy waters surrounding the continent. For example, these fish have evolved special “antifreeze” glycoproteins that prevent the formation of ice in their cells. Some icefishes are “white-blooded” due to no longer making hemoglobin, and some have lost the inducible heat shock response, a nearly universal molecular response to high temperatures. Adding to this repertoire of changes, a recent study published in Molecular Biology and Evolution reveals the genetic mechanisms by which the visual systems of Antarctic icefishes have adapted to both the extreme cold and the unique lighting conditions under Antarctic sea ice.

A team of researchers, led by Gianni Castiglione (now at Vanderbilt University) and Belinda Chang (University of Toronto), set out to explore the impact of sub-zero temperatures on the function and evolution of the Antarctic icefish visual system. The authors focused on rhodopsin, a temperature-sensitive protein involved in vision under dim-light conditions. As noted by Castiglione, a key role for rhodopsin in cold adaptation was suggested by their previous research. “We had previously found cold adaptation in the rhodopsins of high-altitude catfishes from the Andes mountains, and this spurred us into investigating cold adaptation in rhodopsins from the Antarctic icefishes.”

Indeed, the authors observed evidence of positive selection and accelerated rates of evolution in rhodopsins among Antarctic icefishes. Taking a closer look at the specific sites identified as candidates for positive selection, Castiglione and coauthors found two amino acid variants that were absent from other vertebrates. These changes are predicted to have occurred during two key periods in Antarctic icefish history: the evolution of antifreeze glycoproteins and the onset of freezing polar conditions. This timing suggests that these variants were associated with icefish adaptation and speciation in response to climatic events.

To confirm the functional effects of these two amino acid variants, the researchers performed in vitro assays in which they created versions of rhodopsin containing each variant of interest. Both amino acid variants affected rhodopsin’s kinetic profile, lowering the activation energy required for return to a “dark” conformation and likely compensating for a cold-induced decrease in rhodopsin’s kinetic rate. In addition, one of the amino acid changes resulted in a shift in rhodopsin’s light absorbance toward longer wavelengths. This dual functional change came as a surprise to Castiglione and his co-authors. “We were surprised to see that icefish rhodopsin has evolved mutations that can alter both the kinetics and absorbance of rhodopsin simultaneously. We predict that this allows the icefish to adapt their vision to red-shifted wavelengths under sea ice and to cold temperatures through very few mutations.”

Interestingly, the amino acid changes observed in the Antarctic icefishes were distinct from those conferring cold adaptation in the high-altitude catfishes previously studied by the team, suggesting multiple pathways to adaptation in this protein. To continue this line of study, Castiglione and his colleagues hope to investigate cold adaptation in the rhodopsins of other cold-dwelling fish lineages, including Arctic fishes. “Arctic fishes share many of the cold-adapted phenotypes found in the Antarctic icefishes, such as antifreeze proteins. However, this convergent evolution appears to have been accomplished through divergent molecular mechanisms. We suspect this may be the case in rhodopsin as well.”

Unfortunately, acquiring the data needed to conduct such an analysis may prove difficult. “A major obstacle to our research is the difficulty of collecting fishes from Antarctic and Arctic waters,” says Castiglione, “which limits us to publicly available datasets.” This task may become even more challenging in the future as these cold-adapted fish are increasingly affected by warming global temperatures. As Castiglione points out, “Climate change may alter the adaptive landscape of icefishes in the very near future, as sea ice continues to melt, forcing the icefish to very likely find themselves at an evolutionary ‘mismatch’ between their environment and their genetics.”

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JOURNAL

Molecular Biology and Evolution

DOI

10.1093/molbev/msad030 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Adaptation of Antarctic Icefish Vision to Extreme Environments

ARTICLE PUBLICATION DATE

13-Apr-2023

Microplastics can help dangerous bacteria to survive on Scottish beaches 

Reports and Proceedings

MICROBIOLOGY SOCIETY

It has been understood for some time that microplastics provide a protective environment (the so-called ‘plastisphere’) in which bacteria can survive in wastewater. For the first time, researchers at the University of Stirling, Scotland, have tracked how that could enable bacteria to survive the journey to the sea and make their way onto our beaches, where they can come into contact with humans.   

Lead researcher, Rebecca Metcalf, supervised by Professor Richard Quilliam, subjected microplastics colonised by bacteria in wastewater to the different environments that they would likely pass through on their way to our beaches. Metcalf and her team found that, not only could bacteria such a E. coli survive the entire journey, but that viable bacteria also survived for 7 days on the sand.   

“The plastic is providing a substrate for transferring pathogens from wastewater, and through river water, estuary and seawater, and finally up onto the beaches where they are much more likely to come into contact with humans” explains Metcalf. “Other surfaces where bacteria colonise, such as seaweed, wouldn’t necessarily go through that transfer route.”   

Concerned by their findings, Metcalf wanted to see if this theoretical survival was happening on real beaches in Scotland. They collected polyethene and polystyrene plastic waste from 10 Scottish beaches and screened them for 7 target bacteria that cause disease in humans. Alarmingly, they found that these bacteria were present in virtually all of the samples, with some showing resistance to our most commonly used antibiotics.   

This is worrying in light of sewage leaks and wastewater overflows onto our beaches: “We already have sewage ending up in the environment that contains harmful bacteria. But the plastics are transporting bacteria into places where they are more likely to come into contact with people” according to Metcalf.   

“We hope that our research will add to the growing overarching evidence and support for increasing public awareness and ultimately pushes towards legislative changes for plastic discharge to the environment.”    

Research still needs to take place to fully understand the potential risk that this may pose to those bathing at Britain’s beaches, as the likelihood for these pathogens to cause disease in humans is unknown. Researchers still urge the public to take care around plastic pollution but stress the importance of removing plastic from our beaches. “Don’t be afraid of taking part in a beach clean, it is vital that we remove the plastics from our beaches and dispose of them correctly, but I would encourage the public to wash their hands or use gloves.”