Genetic rewiring behind spectacular evolutionary explosion in East Africa

 Genetic rewiring could have driven an evolutionary explosion in the shapes, sizes and adaptations of cichlid fish, in East Africa's answer to Darwin's Galapagos finches.

Published in BMC Genome Biology, an Earlham Institute (EI) study, with collaborators at the University of East Anglia (UEA) and Wisconsin Institute for Discovery, shows that 'genetic rewiring' at non-coding regions -- rather than mutations to protein-coding regions of genes -- may play an important role in how cichlid fish are able to rapidly adapt to fill a staggeringly wide range of environmental niches in the East African Rift lakes.

The results could help future studies to improve breeding of economically important cichlid species such as tilapia -- a staple in aquaculture.

Darwin's famous finches are one of the most well-known examples of evolution by natural selection, and specifically adaptive radiation. The birds he observed on the Galapagos archipelago had differences in their beaks that could be matched to fit their specific feeding habits -- whether they ate big or small seeds, insects, or even used tools to find food.

Amazingly, in the 2-3 million years it took 14 species of finch to evolve on the Galapagos Islands, around 1,000 species of cichlid evolved in Lake Malawi alone.

"In the Great Lakes of East Africa, and within the last few million years, a few ancestral lineages of cichlid fish have independently radiated and given rise to well over 2,000 species -- and we're still finding new ones," says first author Dr Tarang Mehta, a postdoctoral scientist in EI's Haerty Group.

"They occupy a really large diversity of freshwater ecological niches in lakes, rivers and even swamps: this includes sandy substrates, mud, rocks, and vegetated bottoms. As a result, they are all adapted to different dietary habits and niches in these areas."

By looking at gene expression across different cichlid tissues in five representative species from East African rivers and the Great Rift Lakes, the team discovered an evolutionary rewiring of several important genes linked to the adaptability seen in cichlids. The effect which was particularly prominent in the vision of fish species.

"We found out that the most rewired genes are associated with the visual system," explains Dr Mehta. "Essentially, if you look at the different species of fish we used in the study, you could see major differences in the regulation network around opsin genes they use for vision depending on where they live and what they eat.

"For example, the Lake Malawi rock-dwelling species, M. zebra, feeds on UV-absorbing phytoplankton algae. That generally requires increased expression of a particular opsin, SWS1, which helps with sensitivity to UV light. That may well explain why it has a more complex regulatory network around SWS1 compared with the Lake Tanganyika benthivore, N. brichardi, which does not share the same diet or habitat."

Armed with some genes of interest, the team confirmed the mechanisms behind these gene regulatory differences in the lab. Looking at the fine scale, they identified small changes in the DNA sequence of regulatory regions at the start of genes important for trait differences between species, including the visual system.

Rather than the gene itself being modified, it was the regions of DNA known as binding sites that are targeted by transcription factors -- the proteins which determine whether a gene is turned on or turned off. In this way, the different species of fish can be said to have had their visual system 'rewired' for different functions.

Taking this further, the team was able to show that these changes could be commonly associated throughout cichlid fish in Lake Malawi, with diet and ecology-dependent rewiring showing that changes in transcription factor binding could be key to fine-tuning visual sensitivity.

Depending on the trait, cichlids appear to utilise an array of genetic mechanisms to generate phenotypic novelty however, the 'tinkering' of regulatory systems appears more widespread in cichlid fish than previously discovered. This evolutionary plasticity could well explain the explosion of species in such a small area over a relatively short time.

"It's a proof of concept," says Dr Mehta. "As more data comes out, we'll be able to look at this in depth in representative clades from each of the different radiations, not just in Lake Malawi but also Lake Tanganyika, Lake Victoria and even in some of the cichlids in South America."

Professor Federica Di Palma, Professorial Fellow of Biodiversity at UEA, said: "We have released an impressive amount of expression data which will further aid studies into the adaptive radiation of cichlids for the future. We are now deciphering the complexity of these cis-regulatory regions by using genome-wide CRISPR screens.

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Solar activity reconstructed over a millennium

 What goes on in the sun can only be observed indirectly. Sunspots, for instance, reveal the degree of solar activity -- the more sunspots are visible on the surface of the sun, the more active is our central star deep inside. Even though sunspots have been known since antiquity, they have only been documented in detail since the invention of the telescope around 400 years ago. Thanks to that, we now know that the number of spots varies in regular eleven-year cycles and that, moreover, there are long-lasting periods of strong and weak solar activity, which is also reflected in the climate on Earth.

However, how solar activity developed before the start of systematic records has so far been difficult to reconstruct. An international research team led by Hans-Arno Synal and Lukas Wacker of the Laboratory of Ion Beam Physics at ETH, which included the Max Planck Institute for Solar System Research in Göttingen and Lund University in Sweden, has now traced back the sun's eleven-year cycle all the way to the year 969 using measurements of the concentration of radioactive carbon in tree rings. At the same time, the researchers have thus created an important database for more precise age determination using the C14 method. Their results were recently published in the scientific journal Nature Geoscience.

Solar activity from tree rings

To reconstruct solar activity over a millennium with an extremely good time resolution of just one year, the researchers used tree-ring archives from England and Switzerland. In those tree rings, whose ages can be precisely determined by counting the rings, there is a tiny fraction of radioactive carbon C14, with only one out of every 1000 billion atoms being radioactive. From the known half-life of the C14 isotope -- around 5700 years -- one can then deduce the concentration of radioactive carbon present in the atmosphere when the growth ring was formed. As radioactive carbon is mainly produced by cosmic particles, which in turn are kept away from the Earth to a greater or lesser extent by the magnetic field of the sun -- the more active the sun, the better it shields the Earth -- it is possible to deduce solar activity from a change in the concentration of C14 in the atmosphere.

Better results through modern detection techniques

Precise measurements of a change in that already very small concentration, however, resemble the search for a grain of dust on a needle in a huge haystack. "The only measurements of that kind were made in the 80's and 90's," says Lukas Wacker, "but only for the last 400 years and using the extremely laborious counting method." In that method, radioactive decay events of C14 in a sample are directly counted using a Geiger counter, which requires a relatively large amount of material and, owing to the long half-life of C14, even more time. "Using modern accelerator mass spectrometry we were now able to measure the C14 concentration to within 0.1 percent in just a few hours with tree-ring samples that were a thousand times smaller," adds PhD student Nicolas Brehm, who was responsible for those analyses.

In accelerator mass spectrometry, C14 and C12 atoms (the "normal," non-radioactive carbon; C14, by contrast, contains two additional neutrons in its nucleus) of the tree material are first electrically charged and then accelerated by an electric potential of several thousand volts, after which they are sent through a magnetic field. In that magnetic field the two carbon isotopes, which have different masses, are deflected to different degrees and can thus be counted separately. To eventually obtain the desired information on solar activity from that raw data, the researchers have to perform some intricate statistical analysis on it and further process the results using computer models.

Regular eleven-year cycle over a millennium

This procedure enabled the researchers to seamlessly reconstruct solar activity from 969 to 1933. From that reconstruction they could confirm the regularity of the eleven-year cycle as well as the fact that the amplitude of that cycle (by how much the solar activity goes up and down) is also smaller during long-lasting solar minima. Such insights are important for a better understanding of the internal dynamics of the sun. The measurement results also allowed a confirmation of the solar energetic proton event of 993. In such an event, highly accelerated protons that reach the Earth during a solar flare cause a slight overproduction of C14. Moreover, the research team also found evidence of two further, as yet unknown events in 1052 and 1279. This could indicate that such events -- which can severely disturb electronic circuits on Earth and in satellites -- happen more frequently than previously thought.

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Money matters to happiness--perhaps more than previously thought

 What's the relationship between money and well-being? "It's one of the most studied questions in my field," says Matthew Killingsworth, a senior fellow at Penn's Wharton School who studies human happiness. "I'm very curious about it. Other scientists are curious about it. Laypeople are curious about it. It's something everyone is navigating all the time."

To answer this question, Killingsworth collected 1.7 million data points from more than 33,000 participants who provided in-the-moment snapshots of their feelings during daily life. In a paper in the Proceedings of the National Academy of Sciences, Killingsworth confirms that money does influence happiness and, contrary to previous influential research on the subject suggesting that this plateaus above $75,000, there was no dollar value at which it stopped mattering to an individual's well-being.

Killingsworth conducts much of his work using a technique called experience sampling, which asks people to repeatedly fill out short surveys at randomly selected moments during their day. "It tells us what's actually happening in people's real lives as they live them, in millions of moments as they work and chat and eat and watch TV."

Most previous studies of the money-happiness link focused on evaluative well-being, which encompasses overall satisfaction with life. But for this study, Killingsworth aimed to capture both evaluative and experienced well-being, the latter indicating how people feel in the moment.

Through an app he created called Track Your Happiness, people recorded this a few times each day, with check-in times randomized per participant. To measure experienced well-being, each check-in asked them, "How do you feel right now?" on a scale ranging from "very bad" to "very good." At least once during the process, participants also answered the question, "Overall, how satisfied are you with your life?" on a scale of "not at all" to "extremely." This measured evaluative well-being.

Secondary measures of experienced well-being included 12 specific feelings, five positive (confident, good, inspired, interested, and proud) and seven negative (afraid, angry, bad, bored, sad, stressed, and upset). Secondary measures of evaluative well-being included two other measures of life satisfaction collected on an intake survey.

"This process provided repeated snapshots of people's lives, which collectively gives us a composite image, a stop-motion movie of their lives," he says. In total, 33,391 employed, 18- to 65-year-olds in the United States provided 1,725,994 reports of experienced well-being. "Scientists often talk about trying to get a representative sample of the population," he adds. "I was trying to get a representative sample of the moments of people's lives."

Killingsworth then calculated the average level of well-being for each person and analyzed its relationship to people's income. In part, he was trying to confirm the findings of a 2010 paper that suggested that as people earn more money their well-being increases, but experienced well-being plateaus once annual household income hits $75,000.

"It's a compelling possibility, the idea that money stops mattering above that point, at least for how people actually feel moment to moment," he says. "But when I looked across a wide range of income levels, I found that all forms of well-being continued to rise with income. I don't see any sort of kink in the curve, an inflection point where money stops mattering. Instead, it keeps increasing."

Here, "income" refers to a concept known as log(income); rather than each dollar mattering the same to each person, each dollar starts to matter less the more a person earns. "We would expect two people earning $25,000 and $50,000, respectively, to have the same difference in well-being as two people earning $100,000 and $200,000, respectively. In other words, proportional differences in income matter the same to everyone."

Beyond that, Killingsworth's work also provides a deeper understanding of the link between income and happiness.

Higher earners are happier, in part, because of an increased sense of control over life, he says. "When you have more money, you have more choices about how to live your life. You can likely see this in the pandemic. People living paycheck to paycheck who lose their job might need to take the first available job to stay afloat, even if it's one they dislike. People with a financial cushion can wait for one that's a better fit. Across decisions big and small, having more money gives a person more choices and a greater sense of autonomy."

Yet it might be best not to define success in monetary terms, he says. "Although money might be good for happiness, I found that people who equated money and success were less happy than those who didn't. I also found that people who earned more money worked longer hours and felt more pressed for time."

Though the study does show that income matters beyond a previously believed threshold, Killingsworth also doesn't want the takeaway to enforce an idea that people should focus more on money. In fact, he found that, in actuality, income is only a modest determinant of happiness.

"If anything, people probably overemphasize money when they think about how well their life is going," says Killingsworth. "Yes, this is a factor that might matter in a way that we didn't fully realize before, but it's just one of many that people can control and ultimately, it's not one I'm terribly concerned people are undervaluing." Rather, he says he hopes this research can help move forward the conversation in an attempt to find what he calls the "equation for human happiness."

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Study identifies a nonhuman primate model that mimics severe COVID-19 similar to humans

 Aged, wild-caught African green monkeys exposed to the SARS-CoV-2 virus developed acute respiratory distress syndrome (ARDS) with clinical symptoms similar to those observed in the most serious human cases of COVID-19, report researchers in The American Journal of Pathology, published by Elsevier. This is the first study to show that African green monkeys can develop severe clinical disease after SARS-CoV-2 infection, suggesting that they may be useful models for the study of COVID-19 in humans.

"Animal models greatly enhance our understanding of diseases. The lack of an animal model for severe manifestations of COVID-19 has hampered our understanding of this form of the disease," explained lead investigator Robert V. Blair, DVM, PhD, Dip ACVP, Tulane National Primate Research Center, Covington, LA, USA. "If aged green monkeys prove to be a consistent model of severe COVID-19, studying the disease pathobiology in them would improve our understanding of the disease and allow testing treatment options."

The researchers exposed four aged rhesus macaques and four aged African green monkeys to SARS-CoV-2. Older animals (13-16 years of age) were specifically chosen to see if they would develop the severe form of the disease that is observed more frequently in elderly individuals. All of the monkeys developed a spectrum of disease from mild to severe COVID-19. A day after routine screening found no remarkable symptoms, two of the African green monkeys developed rapid breathing that quickly progressed to severe respiratory distress. Radiographic studies found the two African green monkeys had widespread opacities in the lungs, in stark contrast to images taken the day before, highlighting the rapid development of the disease. Such opacities are a hallmark of ARDS in humans.

The African green monkeys that progressed to severe disease had notable increases in plasma cytokines that are compatible with cytokine storm, which is thought to underlie the development of ARDS in some patients. All four African green monkeys had elevated levels of interferon gamma; the two that had progressed to ARDS had the highest plasma concentration. Plasma cytokines were not increased in the rhesus macaques. Dr. Blair suggested that elevated interferon gamma could be explored as a potential predictive biomarker for advanced disease in patients and a possible therapeutic target.

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Synthesis of potent antibiotic follows unusual chemical pathway

 Images of a protein involved in creating a potent antibiotic reveal the unusual first steps of the antibiotic's synthesis. The improved understanding of the chemistry behind this process, detailed in a new study led by Penn State chemists, could allow researchers to adapt this and similar compounds for use in human medicine.

"The antibiotic thiostrepton is very potent against Gram-positive pathogens and can even target certain breast cancer cells in culture," said Squire Booker, a biochemist at Penn State and investigator with the Howard Hughes Medical Institute. "While it has been used topically in veterinary medicine, so far it has been ineffective in humans because it is poorly absorbed. We studied the first steps in thiostrepton's biosynthesis in hopes of eventually being able to hijack certain processes and make analogs of the molecule that might have better medicinal properties. Importantly, this reaction is found in the biosynthesis of numerous other antibiotics, and so the work has the potential to be far reaching."

The first step in thiostrepton's synthesis involves a process called methylation. A molecular tag called methyl group, which is important in many biological processes, is added to a molecule of tryptophan, the reaction's substrate. One of the major systems for methylating compounds that are not particularly reactive, like tryptophan, involves a class of enzymes called radical SAM proteins.

"Radical SAM proteins usually use an iron-sulfur cluster to cleave a molecule called S-adenosyl-L-methionine (SAM), producing a "free radical" or an unpaired electron that helps move the reaction forward," said Hayley Knox, a graduate student in chemistry at Penn State and first author of the paper. "The one exception that we know about so far is the protein involved in the biosynthesis of thiostrepton, called TsrM. We wanted to understand why TsrM doesn't do radical chemistry, so we used an imaging technique called X-ray crystallography to investigate its structure at several stages throughout its reaction."

In all radical SAM proteins characterized to date, SAM binds directly to the iron-sulfur cluster, which helps to fragment the molecule to produce the free radical. However, the researchers found that the site where SAM would typically bind is blocked in TsrM.

"This is completely different from any other radical SAM protein," said Booker. "Instead, the portion of SAM that binds to the cluster associates with the tryptophan substrate and plays a key role in the reaction, in what is called substrate-assisted catalysis."

The researchers present their results in an article appearing Jan. 18 in the journal Nature Chemistry.

In solving the structure, the researchers were able to infer the chemical steps during the first part of thiostrepton's biosynthesis, when tryptophan is methylated. In short, the methyl group from SAM transfers to a part of TsrM called cobalamin. Then, with the help of an additional SAM molecule, the methyl group transfers to tryptophan, regenerating free cobalamin and producing the methylated substrate, which is required for the next steps in synthesizing the antibiotic.

"Cobalamin is the strongest nucleophile in nature, which means it is highly reactive," said Knox. "But the substrate tryptophan is weakly nucleophilic, so a big question is how cobalamin could ever be displaced. We found that an arginine residue sits under the cobalamin and destabilizes the methyl-cobalamin, allowing tryptophan to displace cobalamin and become methylated."

Next the researchers plan to study other cobalamin-dependent radical SAM proteins to see if they operate in similar ways. Ultimately, they hope to find or create analogs of thiostrepton that can be used in human medicine.

"TsrM is clearly unique in terms of known cobalamin-dependent radical SAM proteins and radical SAM proteins in general," said Booker. "But there are hundreds of thousands of unique sequences of radical SAM enzymes, and we still don't know what most of them do. As we continue to study these proteins, we may be in store for many more surprises."

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A 'super-puff' planet like no other

 

W. M. Keck Observatory in Hawaii

The core mass of the giant exoplanet WASP-107b is much lower than what was thought necessary to build up the immense gas envelope surrounding giant planets like Jupiter and Saturn, astronomers at Université de Montréal have found.

This intriguing discovery by Ph.D. student Caroline Piaulet of UdeM's Institute for Research on Exoplanets (iREx) suggests that gas-giant planets form a lot more easily than previously believed.

Piaulet is part of the groundbreaking research team of UdeM astrophysics professor Björn Benneke that in 2019 announced the first detection of water on an exoplanet located in its star's habitable zone.

Published today in the Astronomical Journal with colleagues in Canada, the U.S., Germany and Japan, the new analysis of WASP-107b's internal structure "has big implications," said Benneke.

"This work addresses the very foundations of how giant planets can form and grow," he said. "It provides concrete proof that massive accretion of a gas envelope can be triggered for cores that are much less massive than previously thought."

As big as Jupiter but 10 times lighter

WASP-107b was first detected in 2017 around WASP-107, a star about 212 light years from Earth in the Virgo constellation. The planet is very close to its star -- over 16 times closer than the Earth is to the Sun. As big as Jupiter but 10 times lighter, WASP-107b is one of the least dense exoplanets known: a type that astrophysicists have dubbed "super-puff" or "cotton-candy" planets.

Piaulet and her team first used observations of WASP-107b obtained at the Keck Observatory in Hawai'i to assess its mass more accurately. They used the radial velocity method, which allows scientists to determine a planet's mass by observing the wobbling motion of its host star due to the planet's gravitational pull. They concluded that the mass of WASP-107b is about one tenth that of Jupiter, or about 30 times that of Earth.

The team then did an analysis to determine the planet's most likely internal structure. They came to a surprising conclusion: with such a low density, the planet must have a solid core of no more than four times the mass of the Earth. This means that more than 85 percent of its mass is included in the thick layer of gas that surrounds this core. By comparison, Neptune, which has a similar mass to WASP-107b, only has 5 to 15 percent of its total mass in its gas layer.

"We had a lot of questions about WASP-107b," said Piaulet. "How could a planet of such low density form? And how did it keep its huge layer of gas from escaping, especially given the planet's close proximity to its star?

"This motivated us to do a thorough analysis to determine its formation history."

A gas giant in the making

Planets form in the disc of dust and gas that surrounds a young star called a protoplanetary disc. Classical models of gas-giant planet formation are based on Jupiter and Saturn. In these, a solid core at least 10 times more massive than the Earth is needed to accumulate a large amount of gas before the disc dissipates.

Without a massive core, gas-giant planets were not thought able to cross the critical threshold necessary to build up and retain their large gas envelopes.

How then do explain the existence of WASP-107b, which has a much less massive core? McGill University professor and iREx member Eve Lee, a world-renowned expert on super-puff planets like WASP-107b, has several hypotheses.

"For WASP-107b, the most plausible scenario is that the planet formed far away from the star, where the gas in the disc is cold enough that gas accretion can occur very quickly," she said. "The planet was later able to migrate to its current position, either through interactions with the disc or with other planets in the system."

Discovery of a second planet, WASP-107c

The Keck observations of the WASP-107 system cover a much longer period of time than previous studies have, allowing the UdeM-led research team to make an additional discovery: the existence of a second planet, WASP-107c, with a mass of about one-third that of Jupiter, considerably more than WASP-107b's.

WASP-107c is also much farther from the central star; it takes three years to complete one orbit around it, compared to only 5.7 days for WASP-107b. Also interesting: the eccentricity of this second planet is high, meaning its trajectory around its star is more oval than circular.

"WASP-107c has in some respects kept the memory of what happened in its system," said Piaulet. "Its great eccentricity hints at a rather chaotic past, with interactions between the planets which could have led to significant displacements, like the one suspected for WASP-107b."

Several more questions

Beyond its formation history, there are still many mysteries surrounding WASP-107b. Studies of the planet's atmosphere with the Hubble Space Telescope published in 2018 revealed one surprise: it contains very little methane.

"That's strange, because for this type of planet, methane should be abundant," said Piaulet. "We're now reanalysing Hubble's observations with the new mass of the planet to see how it will affect the results, and to examine what mechanisms might explain the destruction of methane."

The young researcher plans to continue studying WASP-107b, hopefully with the James Webb Space Telescope set to launch in 2021, which will provide a much more precise idea of the composition of the planet's atmosphere.

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Climate change will alter the position of the Earth's tropical rain belt

 Future climate change will cause a regionally uneven shifting of the tropical rain belt -- a narrow band of heavy precipitation near the equator -- according to researchers at the University of California, Irvine and other institutions. This development may threaten food security for billions of people.

In a study published today in Nature Climate Change, the interdisciplinary team of environmental engineers, Earth system scientists and data science experts stressed that not all parts of the tropics will be affected equally. For instance, the rain belt will move north in parts of the Eastern Hemisphere but will move south in areas in the Western Hemisphere.

According to the study, a northward shift of the tropical rain belt over the eastern Africa and the Indian Ocean will result in future increases of drought stress in southeastern Africa and Madagascar, in addition to intensified flooding in southern India. A southward creeping of the rain belt over the eastern Pacific Ocean and Atlantic Ocean will cause greater drought stress in Central America.

"Our work shows that climate change will cause the position of Earth's tropical rain belt to move in opposite directions in two longitudinal sectors that cover almost two thirds of the globe, a process that will have cascading effects on water availability and food production around the world," said lead author Antonios Mamalakis, who recently received a Ph.D. in civil & environmental engineering in the Henry Samueli School of Engineering at UCI and is currently a postdoctoral fellow in the Department of Atmospheric Science at Colorado State University.

The team made the assessment by examining computer simulations from 27 state-of-the-art climate models and measuring the tropical rain belt's response to a future scenario in which greenhouse gas emissions continue to rise through the end of the current century.

Mamalakis said the sweeping shift detected in his work was disguised in previous modelling studies that provided a global average of the influence of climate change on the tropical rain belt. Only by isolating the response in the Eastern and Western Hemisphere zones was his team able to highlight the drastic alterations to come over future decades.

Co-author James Randerson, UCI's Ralph J. & Carol M. Cicerone Chair in Earth System Science, explained that climate change causes the atmosphere to heat up by different amounts over Asia and the North Atlantic Ocean.

"In Asia, projected reductions in aerosol emissions, glacier melting in the Himalayas and loss of snow cover in northern areas brought on by climate change will cause the atmosphere to heat up faster than in other regions," he said. "We know that the rain belt shifts toward this heating, and that its northward movement in the Eastern Hemisphere is consistent with these expected impacts of climate change."

He added that the weakening of the Gulf Stream current and deep-water formation in the North Atlantic is likely to have the opposite effect, causing a southward shift in the tropical rain belt across the Western Hemisphere.

"The complexity of the Earth system is daunting, with dependencies and feedback loops across many processes and scales," said corresponding author Efi Foufoula-Georgiou, UCI Distinguished Professor of Civil & Environmental Engineering and the Henry Samueli Endowed Chair in Engineering. "This study combines the engineering approach of system's thinking with data analytics and climate science to reveal subtle and previously unrecognized manifestations of global warming on regional precipitation dynamics and extremes."

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Inexpensive battery charges rapidly for electric vehicles, reduces range anxiety

 Range anxiety, the fear of running out of power before being able to recharge an electric vehicle, may be a thing of the past, according to a team of Penn State engineers who are looking at lithium iron phosphate batteries that have a range of 250 miles with the ability to charge in 10 minutes.

"We developed a pretty clever battery for mass-market electric vehicles with cost parity with combustion engine vehicles," said Chao-Yang Wang, William E. Diefenderfer Chair of mechanical engineering, professor of chemical engineering and professor of materials science and engineering, and director of the Electrochemical Engine Center at Penn State. "There is no more range anxiety and this battery is affordable."

The researchers also say that the battery should be good for 2 million miles in its lifetime.

They report today (Jan. 18) in Nature Energy that the key to long-life and rapid recharging is the battery's ability to quickly heat up to 140 degrees Fahrenheit, for charge and discharge, and then cool down when the battery is not working.

"The very fast charge allows us to downsize the battery without incurring range anxiety," said Wang.

The battery uses a self-heating approach previously developed in Wang's center. The self-heating battery uses a thin nickel foil with one end attached to the negative terminal and the other extending outside the cell to create a third terminal. Once electrons flow it rapidly heats up the nickel foil through resistance heating and warm the inside of the battery. Once the battery's internal temperature is 140 degrees F, the switch opens and the battery is ready for rapid charge or discharge.

Wang's team modeled this battery using existing technologies and innovative approaches. They suggest that using this self-heating method, they can use low-cost materials for the battery's cathode and anode and a safe, low-voltage electrolyte. The cathode is thermally stable, lithium iron phosphate, which does not contain any of the expensive and critical materials like cobalt. The anode is made of very large particle graphite, a safe, light and inexpensive material.

Because of the self-heating, the researchers said they do not have to worry about uneven deposition of lithium on the anode, which can cause lithium spikes that are dangerous.

"This battery has reduced weight, volume and cost," said Wang. "I am very happy that we finally found a battery that will benefit the mainstream consumer mass market."

According to Wang, these smaller batteries can produce a large amount of power upon heating -- 40 kilowatt hours and 300 kilowatts of power. An electric vehicle with this battery could go from zero to 60 miles per hour in 3 seconds and would drive like a Porsche, he said.

"This is how we are going to change the environment and not contribute to just the luxury cars," said Wang. "Let everyone afford electric vehicles."

Other Penn State researchers working on this project were Xiao-Guang Yang, assistant research professor of mechanical engineering, and Teng Liu, doctoral student in mechanical engineering.

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One small alcoholic drink a day is linked to an increased risk of atrial fibrillation

 A study of nearly 108,000 people has found that people who regularly drink a modest amount of alcohol are at increased risk of atrial fibrillation, a condition where the heart beats in an abnormal rhythm.

The study, published today (Wednesday) in the European Heart Journal, found that, compared to drinking no alcohol at all, just one alcoholic drink a day was linked to a 16% increased risk of atrial fibrillation over an average (median) follow-up time of nearly 14 years. This means that while four teetotallers in 100 might develop atrial fibrillation over the period of the study, five per 100 might develop the condition if they consumed alcohol starting with slightly more than an alcoholic drink a week and more than 75% of them consumed up to one drink a day. The researchers categorised one alcoholic drink as containing 12 g of ethanol, which is the equivalent of a small (120 ml) glass of wine, a small beer (330 ml) or 40 ml of spirits.

It is well known that people who drink a lot of alcohol regularly are at increased risk of developing heart failure, and heart failure can increase the incidence of atrial fibrillation. Several studies have shown a slightly higher risk of heart problems for people who never drink alcohol; they often show that this risk reduces for people who drink a modest amount, and then rises sharply the more alcohol is consumed, creating a 'J' shape on graphs. Until now, it has not been clear whether this was also the case for atrial fibrillation.

However, in the current study led by Professor Renate Schnabel, a consultant cardiologist at the University Heart and Vascular Center, Hamburg-Eppendorf (Germany), researchers found that although low doses of alcohol were associated with a reduced risk of heart failure compared to teetotallers, a similar 'J' shape reduction in risk was not seen for atrial fibrillation. This suggests that the increased risk of atrial fibrillation among people drinking small amounts of alcohol was not triggered by heart failure.

Prof. Schnabel said: "To our knowledge, this is the largest study on alcohol consumption and long-term incidence of atrial fibrillation in the community. Previous studies have not had enough power to examine this question, although they have been able to show a relationship between alcohol intake and other heart and blood vessel problems, such as heart attack and heart failure. In our study, we can now demonstrate that even very low regular alcohol consumption may increase the risk of atrial fibrillation.

"These findings are important as the regular consumption of alcohol, the 'one glass of wine a day' to protect the heart, as is often recommended for instance in the lay press, should probably no longer be suggested without balancing risks and possible benefits for all heart and blood vessel diseases, including atrial fibrillation."

The researchers analysed information on 107,845 people taking part in five community-based studies in Sweden, Norway, Finland, Denmark and Italy. The participants underwent medical examinations at the time they joined the studies between 1982 and 2010 and provided information on their medical histories, lifestyles (including alcohol and tobacco consumption), employment and education levels. A total of 100,092 participants did not have atrial fibrillation when they enrolled and their median age was nearly 48 years (range 24-97 years).

During the median follow-up period of nearly 14 years, 5,854 people developed atrial fibrillation. The associations between alcohol consumption and the risk of atrial fibrillation were similar for all types of alcoholic drinks and for men and women.

In addition to the 16% increased risk of atrial fibrillation compared to teetotallers seen in people who consumed only one alcoholic drink a day, the researchers found that the risk increased with increasing alcohol intake; up to two drinks a day was associated with a 28% increased risk and this went up to 47% for those who consumed more than four.

The exact mechanisms by which modest amounts of alcohol could trigger atrial fibrillation are not known. Studies have shown that heavy drinking over a short period of time can trigger 'holiday heart syndrome' in some people, and in some atrial fibrillation patients, small amounts of alcohol can trigger arrhythmia episodes.

Limitations of the study include the fact that study participants reported the type and quantity of alcohol they drank and this could lead to under-reporting; the information available did not enable the researchers to look at the effects of binge drinking; some episodes of atrial fibrillation can be asymptomatic and so may not have been reported; only adults across Europe were included in the analyses and so it may not be possible for the results to be generalised to other populations; as the study was observational, it can show only an association between alcohol intake and atrial fibrillation and not that alcohol causes atrial fibrillation.

In an accompanying editorial, Jorge A. Wong and David Conen from the Population Health Research Institute at McMaster University, Hamilton, Canada, write that the research "makes an important contribution to our understanding of the relationship between alcohol intake and incident AF, in particular at the lower spectrum of alcohol consumption. A significant relationship between alcohol and AF was identified, and even small quantities of alcohol were associated with an increased, albeit small, risk of incident AF.

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2020 tied for warmest year on record, NASA analysis shows

 

Thermometer and sky background.

Earth's global average surface temperature in 2020 tied with 2016 as the warmest year on record, according to an analysis by NASA.

Continuing the planet's long-term warming trend, the year's globally averaged temperature was 1.84 degrees Fahrenheit (1.02 degrees Celsius) warmer than the baseline 1951-1980 mean, according to scientists at NASA's Goddard Institute for Space Studies (GISS) in New York. 2020 edged out 2016 by a very small amount, within the margin of error of the analysis, making the years effectively tied for the warmest year on record.

"The last seven years have been the warmest seven years on record, typifying the ongoing and dramatic warming trend," said GISS Director Gavin Schmidt. "Whether one year is a record or not is not really that important -- the important things are long-term trends. With these trends, and as the human impact on the climate increases, we have to expect that records will continue to be broken."

A Warming, Changing World

Tracking global temperature trends provides a critical indicator of the impact of human activities -- specifically, greenhouse gas emissions -- on our planet. Earth's average temperature has risen more than 2 degrees Fahrenheit (1.2 degrees Celsius) since the late 19th century.

Rising temperatures are causing phenomena such as loss of sea ice and ice sheet mass, sea level rise, longer and more intense heat waves, and shifts in plant and animal habitats. Understanding such long-term climate trends is essential for the safety and quality of human life, allowing humans to adapt to the changing environment in ways such as planting different crops, managing our water resources and preparing for extreme weather events.

Ranking the Records

A separate, independent analysis by the National Oceanic and Atmospheric Administration (NOAA) concluded that 2020 was the second-warmest year in their record, behind 2016. NOAA scientists use much of the same raw temperature data in their analysis, but have a different baseline period (1901-2000) and methodology. Unlike NASA, NOAA also does not infer temperatures in polar regions lacking observations, which accounts for much of the difference between NASA and NOAA records.

Like all scientific data, these temperature findings contain a small amount of uncertainty -- in this case, mainly due to changes in weather station locations and temperature measurement methods over time. The GISS temperature analysis (GISTEMP) is accurate to within 0.1 degrees Fahrenheit with a 95 percent confidence level for the most recent period.

Beyond a Global, Annual Average

While the long-term trend of warming continues, a variety of events and factors contribute to any particular year's average temperature. Two separate events changed the amount of sunlight reaching the Earth's surface. The Australian bush fires during the first half of the year burned 46 million acres of land, releasing smoke and other particles more than 18 miles high in the atmosphere, blocking sunlight and likely cooling the atmosphere slightly. In contrast, global shutdowns related to the ongoing coronavirus (COVID-19) pandemic reduced particulate air pollution in many areas, allowing more sunlight to reach the surface and producing a small but potentially significant warming effect. These shutdowns also appear to have reduced the amount of carbon dioxide (CO2) emissions last year, but overall CO2 concentrations continued to increase, and since warming is related to cumulative emissions, the overall amount of avoided warming will be minimal.

The largest source of year-to-year variability in global temperatures typically comes from the El Nino-Southern Oscillation (ENSO), a naturally occurring cycle of heat exchange between the ocean and atmosphere. While the year has ended in a negative (cool) phase of ENSO, it started in a slightly positive (warm) phase, which marginally increased the average overall temperature. The cooling influence from the negative phase is expected to have a larger influence on 2021 than 2020.

"The previous record warm year, 2016, received a significant boost from a strong El Nino. The lack of a similar assist from El Nino this year is evidence that the background climate continues to warm due to greenhouse gases," Schmidt said.

The 2020 GISS values represent surface temperatures averaged over both the whole globe and the entire year. Local weather plays a role in regional temperature variations, so not every region on Earth experiences similar amounts of warming even in a record year. According to NOAA, parts of the continental United States experienced record high temperatures in 2020, while others did not.

In the long term, parts of the globe are also warming faster than others. Earth's warming trends are most pronounced in the Arctic, which the GISTEMP analysis shows is warming more than three times as fast as the rest of the globe over the past 30 years, according to Schmidt. The loss of Arctic sea ice -- whose annual minimum area is declining by about 13 percent per decade -- makes the region less reflective, meaning more sunlight is absorbed by the oceans and temperatures rise further still. This phenomenon, known as Arctic amplification, is driving further sea ice loss, ice sheet melt and sea level rise, more intense Arctic fire seasons, and permafrost melt.

Land, Sea, Air and Space

NASA's analysis incorporates surface temperature measurements from more than 26,000 weather stations and thousands of ship- and buoy-based observations of sea surface temperatures. These raw measurements are analyzed using an algorithm that considers the varied spacing of temperature stations around the globe and urban heating effects that could skew the conclusions if not taken into account. The result of these calculations is an estimate of the global average temperature difference from a baseline period of 1951 to 1980.

NASA measures Earth's vital signs from land, air, and space with a fleet of satellites, as well as airborne and ground-based observation campaigns. The satellite surface temperature record from the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aura satellite confirms the GISTEMP results of the past seven years being the warmest on record. Satellite measurements of air temperature, sea surface temperature, and sea levels, as well as other space-based observations, also reflect a warming, changing world. The agency develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. NASA shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

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