It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Four-and-a-half billion years ago, Earth would have been hard to recognise. Instead of the forests, mountains and oceans that we know today, the surface of our planet was covered entirely by magma - the molten rocky material that emerges when volcanoes erupt. This much the scientific community agrees on. What is less clear is what the atmosphere at the time was like. New international research efforts led by Paolo Sossi, senior research fellow at ETH Zurich and the NCCR PlanetS, attempt to lift some of the mysteries of Earth's primeval atmosphere. The findings were published today in the journal Science Advances.
Making magma in the laboratory
"Four-and-a-half billion years ago, the magma constantly exchanged gases with the overlying atmosphere," Sossi begins to explain. "The air and the magma influenced each other. So, you can learn about one from the other."
To learn about Earth's primeval atmosphere, which was very different from what it is today, the researchers therefore created their own magma in the laboratory. They did so by mixing a powder that matched the composition of Earth's molten mantle and heating it. What sounds straightforward required the latest technological advances, as Sossi points out: "The composition of our mantle-like powder made it difficult to melt - we needed very high temperatures of around 2,000° Celsius."
That required a special furnace, which was heated by a laser and within which the researchers could levitate the magma by letting streams of gas mixtures flow around it. These gas mixtures were plausible candidates for the primeval atmosphere that, as 4.5 billion years ago, influenced the magma. Thus, with each mixture of gases that flowed around the sample, the magma turned out a little different.
"The key difference we looked for was how oxidised the iron within the magma became," Sossi explains. In less accurate words: how rusty. When iron meets oxygen, it oxidises and turns into what we commonly refer to as rust. Thus, when the gas mixture that the scientists blew over their magma contained a lot of oxygen, the iron within the magma became more oxidised.
This level of iron oxidation in the cooled-down magma gave Sossi and his colleagues something that they could compare to naturally occurring rocks that make up Earth's mantle today - so-called peridotites. The iron oxidation in these rocks still has the influence of the primeval atmosphere imprinted within it. Comparing the natural peridotites and the ones from the lab therefore gave the scientists clues about which of their gas mixtures came closest to Earth's primeval atmosphere.
A new view of the emergence of life
"What we found was that, after cooling down from the magma state, the young Earth had an atmosphere that was slightly oxidising, with carbon dioxide as its main constituent, as well as nitrogen and some water," Sossi reports. The surface pressure was also much higher, almost one hundred times that of today and the atmosphere was much higher, due to the hot surface. These characteristics made it more similar to the atmosphere of today's Venus than to that of today's Earth.
This result has two main conclusions, according to Sossi and his colleagues: The first is that Earth and Venus started out with quite similar atmospheres but the latter subsequently lost its water due to the closer proximity to the sun and the associated higher temperatures. Earth, however, kept its water, primarily in the form of oceans. These absorbed much of the CO2 from the air, thereby reducing the CO2 levels significantly.
The second conclusion is that a popular theory on the emergence of life on Earth now seems much less likely. This so-called "Miller-Urey experiment", in which lightning strikes interact with certain gases (notably ammonia and methane) to create amino acids - the building blocks of life - would have been difficult to realise. The necessary gases were simply not sufficiently abundant.
Study in Thailand identifies benefits of community-based freshwater fish reserves
Results of research published in science journal Nature could help freshwater fisheries worldwide
IMAGE: FIELDWORK IN COMMUNITIES OFTEN RESULTS IN CURIOUS ONLOOKERS, PRESENTING A GREAT OPPORTUNITY FOR INCLUSION AND AWARENESS RAISING. HERE TWO REGULAR OBSERVERS HELP AARON KONING RELEASE A RADIO-TAGGED MAHSEER AS PART... view more
CREDIT: PHOTO COURTESY OF UNIVERSITY OF NEVADA, RENO.
RENO, Nevada - Freshwater fish reserves are extraordinarily successful at protecting multiple species of fish, a new study of a network of community-based reserves in Thailand has found.
Aaron Koning, a postdoctoral research fellow at the University of Nevada, Reno's Global Water Center, spent seven years studying a network of freshwater protected areas (fish reserves) that communities established in one branch of the Salween River Basin in northern Thailand.
He mapped more than 50 reserves, all community organized and managed independently of government support, throughout the river and its branches. The area supports more than 40 species of fish, ranging from large minnows to catfish to needlefish. The results are published today in the scientific journal Nature in the article "A network of grassroots reserves protects tropical river fish diversity."
"The conservation benefits of each reserve established independently by local Pgagayaw, or Karen, indigenous communities are remarkable, and the collective benefits for fish within the entire network of reserves are even greater," Koning said. "Twenty-seven years ago, one community created a reserve in an effort to protect their fish, and since then reserves have spread among communities throughout the valley. It's a great story of effective community-based resource management."
Koning worked with a team of scientists who he had known from his work at the University of Wisconsin-Madison: Martin Perales from the University of Wisconsin-Madison; Etienne Fluet-Chouinard, now from Stanford University, and aquatic conservation ecologist and Associate Professor Peter McIntyre of Cornell University.
"During six weeks of fieldwork related to this study, Martin and I lived with friends in riverside villages, but made the 90 minute drive to Mae Sarieng for internet access on a couple of weekends."
They bounced around the study area of the 50-mile-long Mae Ngao River in a 1999 Toyota Hilux 4X4 truck, through the various regions and communities, including teak forests and upland agricultural areas with rice paddies and soybean crops.
"When I initially started documenting the locations of reserves several years ago, I tried to find the locations of as many reserves within the basin as I could by exploring every road and trail on the map, and many that weren't on any map," he said. "For our fish surveys, we selected a set of 23 reserves distributed throughout the river basin that broadly represented all of the reserves. While there are probably 40 species within this river valley, in this study we regularly observed 33 species of fish."
Intensive fisheries have reduced fish biodiversity and abundance in aquatic ecosystems worldwide. No-take reserves have become a cornerstone of marine ecosystem-based fisheries management. The team used the knowledge gained from decades of study on marine reserves to test if the same principles of success might apply to this network of riverine reserves, where one might not think reserves would work.
"The applicability of this marine reserve network paradigm to riverine biodiversity and inland fisheries remains largely untested," Koning said. "Our research shows that freshwater reserves created by 23 separate communities in Thailand's Salween basin have dramatically increased fish richness, density and biomass when compared to adjacent areas. One river reserve is 1,000 feet long and just 12 feet wide in dry season, but you can see fish everywhere."
Underwater fish surveys were done using masks and snorkels with lots of crawling over and around rocks underwater. In many reserves, the abundance and size of fish seeking protection was evident by eye from the river bank in the dry season.
McIntyre, now Koning's colleague in this research, was once his doctoral advisor at the University of Wisconsin, and co-advisor for his postdoctoral work at Cornell. McIntyre said he was shocked that the reserves worked so well.
"When you see piles of fish in each of these reserves, it is clear that something big is happening," he said. "Questions remain about whether the fish populations are viable in the long run, and how durable the governance approach will prove, but this unique experiment in conservation still has much to teach us."
Despite their small size, grassroots reserves enhanced the species richness, density and biomass of protected fish communities enormously. Relative to adjacent fished areas with comparable water depth and substrate composition, reserves held 27% more fish species; 124% higher fish density and an astounding 2,247% higher biomass on average.
"Our results demonstrate that small reserves have great benefits for intensively harvested fishes in this tropical river, even though their collective area encompasses only 2% of the channel in our study catchment," Koning said. "The area of individual reserves ranged from just a half acre up to six acres."
"One of the most important findings is that the network of reserves adds benefits beyond those arising from any single reserve," McIntyre said. "Another key lesson is that communities have the power to protect the resource themselves, in a way that doesn't prevent them from using it intensively outside of the reserve boundary."
This study demonstrates that fish reserves can work well in subsistence fisheries targeting rivers, thereby offering a model for protecting fish biodiversity and offsetting overfishing in rivers worldwide. The study is especially timely given that overharvest of fisheries threatens thousands of species and the food security of hundreds of millions of people around the world.
"Freshwaters are under-represented among the world's protected areas, and our findings suggest that networks of small, community-based reserves offer a generalizable model for protecting biodiversity and augmenting fisheries as the world's rivers face unprecedented pressures," Koning said.
In Southeast Asia, riverine reserves are commonplace; hundreds of communities have designated no-fishing zones that together form de facto reserve networks in rivers throughout the region.
The idea has the potential to be a big step forward in terms of freshwater biodiversity protection, not just in Thailand but worldwide. These results and the model could be applied in freshwater ecosystems worldwide - including highly diverse and highly threatened tropical rivers such as the Amazon, Congo and Mekong Rivers.
McIntyre echoed Koning's take on the potential for worldwide implementation.
"Aaron's findings offer a great model for other parts of the world, "he said. "The role of cultural traditions and governance structure can't be overstated, so we do not expect simplistic transferability. However, many of the principles identified could be applicable to subsistence fisheries elsewhere."
Koning is currently a postdoctoral researcher working with Zeb Hogan and based at the University of Nevada, Reno's Global Water Center in the College of Science.
Koning and Hogan, an aquatic conservation ecologist, along with Sudeep Chandra, the Director of the Global Water Center at the University of Nevada, Reno will be replicating the Thailand study on Cambodian rivers as part of their Wonders of the Mekong project, a comprehensive approach to fish conservation, economics and cultural values.
CAPTION
Spawning events along the Mae Ngao River one branch of the Salween River Basin in northern Thailand occur in January. Even though some of the reserves are small in size, the fish seem to live their entire life cycles there
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The Wonders of the Mekong Project, a partnership with the Inland Fisheries Research and Development Institute of Cambodia with funding from U.S. Agency for International Development, is led by Hogan. They conduct applied research, working to build capacity and develop outreach and communications products to highlight the economic, ecological, and cultural values of biodiversity and ecosystem services associated with the Lower Mekong River. The Wonders project will be building on the findings of this Mae Ngao River study. A short video describes the research: https://www.youtube.com/watch?v=l6dlDy90J74&feature=youtu.be
Community conservation reserves protect fish diversity in tropical rivers
ITHACA, N.Y. - Prohibiting fishing in conservation reserves is a common strategy for protecting ocean ecosystems and enhancing fisheries management. However, such dedicated reserves are rare in freshwater ecosystems, where conservation efforts generally piggyback on the protection of terrestrial habitats and species.
Now, a collaboration between researchers from Cornell University and the University of Wisconsin-Madison has found that small, community-based reserves in Thailand's Salween River Basin are serving as critical refuges for fish diversity in a region whose subsistence fisheries have suffered from decades of overharvesting.
The team's paper, "A Network of Grassroots Reserves Protects Tropical River Fish Diversity," published Nov. 25 in Nature.
The lead author is Aaron Koning, a former postdoctoral fellow with the Cornell Atkinson Center for Sustainability who is currently a postdoctoral researcher at the University of Nevada, Reno. The project was overseen by Pete McIntyre, the Dwight Webster Sesquicentennial Faculty Fellow and associate professor of natural resources and environment at Cornell University.
Freshwater ecosystems across the world have experienced rapid species declines compared to ecosystems on land or in the ocean. One of the leading causes is overfishing, particularly in regions where fish are a vital source of human nutrition.
Koning launched his work in Thailand as a doctoral student with McIntyre at the University of Wisconsin-Madison, with the goal of testing whether the benefits documented from marine conservation reserves might also apply to freshwater systems. Both researchers came to Cornell in 2018 and continued to work on the project with their collaborators at UW-Madison.
They focused on the Mae Ngao River along Thailand's border with Myanmar, because Southeast Asia has an unusually long history of freshwater conservation reserves. In 2012, Koning began documenting more than 50 reserves spread over 1,000 square kilometers of the river valley. Each of these reserves had been created by a local community to support its own nearby fishing grounds.
"It was really striking to see this largely uncoordinated effort of grassroots actors who pursued this fascinating conservation strategy of their own volition, and they keep doing it because they can see the benefits in their catches," Koning said. "That really motivated me to ask the questions: Why does this work and could it work elsewhere?"
The researchers surveyed fish communities in 23 separate reserves that ranged in length from 300 meters to 2 kilometers. Compared to adjacent areas where fishing is unrestricted and intense, the grassroots reserves contained on average 27% more fish species and 124% higher fish density, with a more than twentyfold increase in overall biomass.
"Generally, we think of rivers as systems where things flow through and fish move around constantly, so what effect could a small reserve possibly have?" Koning said. "But just having a few hundred meters where people aren't fishing, while they're fishing like crazy everywhere else, can consistently produce these big changes."
One of the key characteristics for successful reserves was location. When reserves are placed within view of local villages, the community members can enforce conservation rules and deter poachers.
"Residents can literally see the large fish from their homes - it's pretty compelling," McIntyre said.
Fish longer than 20 centimeters (approximately 8 inches) were almost entirely restricted to the reserves, and larger reserves saw the biggest bump in fish diversity and size. Community members reported that having the reserves over time helped them to catch larger fish. This indicates the reserves not only protect biodiversity but can also bolster the food security of local populations, especially during the dry season when farmers have collected their crops and turn to subsistence fishing to supplement their families' diets.
"As if the local benefits were not amazing enough, we were fascinated to see a further benefit of having other reserves nearby. These fish populations appear to be linked, yielding synergistic gains when the ad hoc network of reserves allows exchange among protected areas," McIntyre said.
The team's findings aligned with the theoretical predictions made by marine conservation models, which led the researchers to suspect the grassroots reserves could be a successful strategy for other regions that have been overharvested, such as in the Mekong, Amazon and Congo rivers, where intensive fisheries feed millions of people.
"This is a great example of communities engaging in conservation on their own, and being successful," Koning said. "If we can take that reality, mix it with what we already know from marine systems, then maybe we can marry these things and design a system of small reserves that maximize conservation benefits while improving fishery benefits for communities, too."
Koning is now working with Zeb Hogan, an aquatic ecologist at the University of Nevada-Reno who hosts the National Geographic network program "Monster Fish," to study this conservation approach at larger scales in the Mekong River basin.
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The research was supported by the National Science Foundation, the Mustard Seed Foundation, and the David and Lucile Packard Foundation, in addition to the Cornell Atkinson Center for Sustainability.
New study explains important cause of fatal influenza
It is largely unknown why influenza infections lead to an increased risk of bacterial pneumonia. Researchers at Karolinska Institutet in Sweden have now described important findings leading to so-called superinfections, which claim many lives around the world every year. The study is published in the journal PNAS, Proceedings of the National Academy of Sciences, and can also contribute to research on COVID-19.
The Spanish Flu was an influenza pandemic that swept across the world in 1918-20 and unlike many other pandemics disproportionately hit young otherwise healthy adults. One important reason for this was so-called superinfections caused by bacteria, in particular pneumococci.
Influenza is caused by a virus, but the most common cause of death is secondary bacterial pneumonia rather than the influenza virus per se. Pneumococcal infections are the most common cause of community-acquired pneumonia and a leading global cause of death. A prior influenza virus infection sensitizes for pneumococcal infections, but mechanisms behind this increase susceptibility are not fully understood. Researchers at Karolinska Institutet have now identified influenza-induced changes in the lower airways that affect the growth of pneumococci in the lungs.
Using an animal model, the researchers found that different nutrients and antioxidants, such as vitamin C and other normally cell protective substances leak from the blood, thereby creating an environment in the lungs that favours growth of the bacteria. The bacteria adapt to the inflammatory environment by increasing the production of the bacterial enzyme HtrA.
The presence of HtrA weakens the immune system and promotes bacterial growth in the influenza-infected airways. The lack of HtrA stops bacterial growth.
"The ability of pneumococcus to grow in the lower airways during an influenza infection seems to depend on the nutrient-rich environment with its higher levels of antioxidants that occurs during a viral infection, as well as on the bacteria's ability to adapt to the environment and protect itself from being eradicated by the immune system," says principal investigator Birgitta Henriques Normark, professor at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet.
The results provide valuable information on how bacteria integrate with their environment in the lungs and could be used to find new therapies for double infections between the influenza virus and pneumococcal bacteria.
"HtrA is an enzyme, a protease, which helps to weaken the immune system and allows pneumococcal bacteria to penetrate the protective cell layer on the inside of the airways," explains the paper's first author Vicky Sender, researcher at the same department. "A possible strategy can therefore be use of protease inhibitors to prevent pneumococcal growth in the lungs."
It is still not known if COVID-19 patients are also sensitive to such secondary bacterial infections, but the researchers think that similar mechanisms could potentially be found in severely ill COVID-19 patients.
"It's likely that acute lung inflammation, regardless of cause, gives rise to leakage of nutrients and antioxidants, and to an environment that fosters bacterial growth," says Professor Henriques Normark.
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The study was financed with grants from the Knut and Alice Wallenberg Foundation, the Swedish Research Council, the Swedish Foundation for Strategic Research, Region Stockholm, the National Technological University (Singapore), the National Research Foundation Fellowship (Singapore), the National University of Singapore, ESCMID, BioMS and the National Medical Research Council. There are no declared conflicts of interest.
Publication: "Capillary leakage provides nutrients and antioxidants for rapid pneumococcal proliferation in influenza-infected lower airways". Vicky Sender, Karina Hentrich, Anuj Pathak, Alicia Tan Qian Ler, Bethel Tesfai Embaie, Susanna L. Lundström, Massimiliano Gaetani, Jan Bergstrand, Rei Nakamoto, Lok-To Sham, Jerker Widengren, Staffan Normark, and Birgitta Henriques-Normark. Proceedings of the National Academy of Sciences, online 23 November 2020, doi: 10.1073/pnas.2012265117.
The invasive species that Europe needs to erradicate most urgently are identified
Species such as the golden apple snail are putting the agricultural sector in the Ebro river basin in quite a predicament. Meanwhile, in the southern part of the Iberian Peninsula, water hyacinths are threatening to destroy the natural ecosystem of the Guadiana River. Invasive species change not only the habitat of many other species but they also directly impact the region's economy. Some of these species are already wreaking havoc on certain areas but others could do so in the future and have a huge impact, both environmentally and financially.
In order to help management centers and administrations make decisions, an international team of European researchers, led by the University of Newcastle and the Belgian Nature and Forests Agency with which the University of Córdoba collaborated, assessed the priority of erradicating different invasive species in Europe. One of the new aspects they also included is a study of possible scenarios regarding invasive species that are not currently present in the region or that are in an emerging stage, for which there are still opportunities to curb their spread.
"It would be ideal to erradicate all the invasive species but financial and labor resources are limited, even more so now, when we are dealing with other priorities", explains researcher Pablo González Moreno, an expert on invasive species and a member of the ERSAF (Assessment and Restoration of Farming and Forest Systems) group at the University of Córdoba, who collaborated on the study, researching the feasibility of erradicating different invasive plant species.
One of the species identified as a very high priority is the common myna from the starling family that has been able to establish small colonies in Spain and Portugal and that, due to its aggressive territorial nature and ability to adapt, could spread to more areas and displace other native species. Other very high priority species for Europe are the Berber toad, the ring-tailed coati (a carnivorous mammal) and the red-vented bulbul, another bird species.
Among the species that have yet to arrive in Europe but that could in the future, the highest priority is for the rusty crayfish (Faxonius rusticus), a freshwater crayfish that is causing serious problems in the northern US and Canada. Also a priority are the northern snakehead (Channa argus), an Asian fish that came to the US via collectors who had purchased them, and Cryptostegia grandiflora, a kind of vine native to Madagascar.
In order to draw up this list, the international team first analyzed the risk of establishment, spreading and the impact of different invasive species. This research was previously published and financed by the European Union. This risk ranking was compared to an assessment of erradication strategies for these species in terms of effectiveness, cost, level of acceptance by different social sectors, estimated time needed to act and possibility of the species coming back after being erradicated.
Having analyzed feasibility, the team met up to pool their assessments and together drew up a list of invasive species already established in Europe, as well as those who could do so in the future, according to their priority, supplying data on the regions where they are found or could be found, the erradication method, their effectiveness and their minimum and maximum cost, among other things. This is an open access list and any person or entity can consult it.
In this aspect, this study is important, not only in helping to manage the invasive species currently found in Europe, but also in having a future management scenario in case these species are able to get to Europe.
At a European level, this research has been able to create a network of researchers partnering up with managers in several European countries. "This is a way for the collective to get in touch with each other and to reach consensuses on the degree of management, something that was proving difficult to do in Europe. Having European regulations is an important step. Invasive species don't understand what borders are", concludes researcher Pablo González.
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Olaf Booy, Pete A. Robertson, Niall Moore, Jess Ward, Helen E. Roy, Tim Adriaens, Richard Shaw, Johan Van Valkenburg, Gabrielle Wyn, Sandro Bertolino, Olivier Blight, Etienne Branquart, Giuseppe Brundu, Joe Caffrey, Dario Capizzi, Jim Casaer, Olivier De Clerck, Neil E. Coughlan, Eithne Davis, Jaimie T. A. Dick, Franz Essl, Guillaume Fried, Piero Genovesi, Pablo González-Moreno, Frank Huysentruyt, Stuart R. Jenkins, Francis Kerckhof, Frances E. Lucy, Wolfgang Nentwig, Jonathan Newman, Wolfgang Rabitsch, Sugoto Roy, Uwe Starfinger, Paul D. Stebbing, Jan Stuyck, Mike Sutton-Croft, Elena Tricarico, Sonia Vanderhoeven, Hugo Verreycken, Aileen C. Mill. Using structured eradication feasibility assessment to prioritize the management of new and emerging invasive alien species in Europe.Global Change Biology. https://doi.org/10.1111/gcb.15280
Russian scientists improve 3D printing technology for aerospace composites using oil waste
NATIONAL UNIVERSITY OF SCIENCE AND TECHNOLOGY MISIS
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
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
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).
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".
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
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
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."
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.
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
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.
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 MartÃn, one of the programme's coordinators.
