As the driver of global atmospheric and ocean circulation, the tropics play a central role in understanding past and future climate change. Both global climate simulations and worldwide ocean temperature reconstructions indicate that the cooling in the tropics during the last cold period, which began about 115,000 years ago, was much weaker than in the temperate zone and the polar regions. The extent to which this general statement also applies to the tropical high mountains of Eastern Africa and elsewhere is, however, doubted on the basis of palaeoclimatic, geological and ecological studies at high elevations.

A research team led by Alexander Groos, Heinz Veit (both from the Institute of Geography) and Naki Akcar (Institute of Geological Sciences) at the University of Bern, in collaboration with colleagues from ETH Zurich, the University of Marburg and the University of Ankara, used the Ethiopian Highlands as a test site to investigate the extent and impact of regional cooling on tropical mountains during the last glacial period. The results have been published in the scientific journals Science Advances and Earth Surface Dynamics.

A 340-metre-wide space rock named Apophis whizzed safely past Earth on 6 March. The next time it returns, in 2029, won't be so uneventful: Apophis will come within 40,000 kilometres of the planet, skimming just above the region where some high-flying satellites orbit. It will be the first time that astronomers will be able to watch such a big asteroid pass so close to us.

Last week's fly-by gave scientists a chance to test the worldwide planetary defence system, in which astronomers quickly assess the chances of an asteroid hitting Earth as they follow its path across the night sky. "It's a fire drill with a real asteroid," says Vishnu Reddy, a planetary scientist at the University of Arizona in Tucson who coordinated the observing campaign.

The Apophis fly-by highlights how much astronomers have learnt about near-Earth asteroids — and how much they still have to learn. Since 1998, when NASA kicked off the biggest search for near-Earth asteroids, scientists have detected more than 25,000 of them. And 2020 turned out to be a record year for discoveries. Despite the COVID-19 pandemic interrupting many of the surveys, astronomers catalogued 2,958 previously unknown near-Earth asteroids over the course of the year (see 'Space rocks').

It has long been understood that a parent's DNA is the principal determinant of health and disease in offspring. Yet inheritance via DNA is only part of the story; a father's lifestyle such as diet, being overweight and stress levels have been linked to health consequences for his offspring. This occurs through the epigenome - heritable biochemical marks associated with the DNA and proteins that bind it. But how the information is transmitted at fertilization along with the exact mechanisms and molecules in sperm that are involved in this process has been unclear until now.

A new study from McGill, published recently in Developmental Cell, has made a significant advance in the field by identifying how environmental information is transmitted by non-DNA molecules in the sperm. It is a discovery that advances scientific understanding of the heredity of paternal life experiences and potentially opens new avenues for studying disease transmission and prevention.

A paradigm shift in understanding of heredity

"The big breakthrough with this study is that it has identified a non-DNA based means by which sperm remember a father's environment (diet) and transmit that information to the embryo," says Sarah Kimmins, PhD, the senior author on the study and the Canada Research Chair in Epigenetics, Reproduction and Development. The paper builds on 15 years of research from her group. "It is remarkable, as it presents a major shift from what is known about heritability and disease from being solely DNA-based, to one that now includes sperm proteins. This study opens the door to the possibility that the key to understanding and preventing certain diseases could involve proteins in sperm."

"When we first started seeing the results, it was exciting, because no one has been able to track how those heritable environmental signatures are transmitted from the sperm to the embryo before," adds PhD candidate Ariane Lismer, the first author on the paper. "It was especially rewarding because it was very challenging to work at the molecular level of the embryo, just because you have so few cells available for epigenomic analysis. It is only thanks to new technology and epigenetic tools that we were able to arrive at these results."

The automaker will slowly phase out existing combustion engines and replace them with all-electric drivetrains.

Audi has an impressive slate of internal combustion engines on offer at the moment, including the 591-hp twin-turbo 4.0-liter V-8 you see above, powering the jaw-dropping RS 6 Avant super-wagon. And let's not forget the sonorous naturally aspirated V-10 in the mid-engine R8. But according to the CEO of the company, the automaker will not develop any new internal combustion engines, and will begin phasing out the current gasoline and diesel engines and replacing them with electric powertrains.

In an interview with German-language industry news outlet Automobilwoche, Audi CEO Marcus Duesmann confirmed the decision. "We will no longer develop a new internal combustion engine, but will adapt our existing internal combustion engines to new emission guidelines," Duesmann told the publication (as translated by Google).

Duesmann cited (and slighted) the increasing challenges of emissions regulations in the decision:

"The EU plans for an even stricter Euro 7 emissions standard are a huge technical challenge and at the same time have little benefit for the environment. That extremely restricts the combustion engine."

A team of scientists has developed a model that would allow for the existence of traversable wormholes that adhere to the laws of physics without the need for theoretical matter to keep them open. But there's a catch.

The concept of wormholes harken back to the earliest days of Albert Einstein and Nathan Rosen's work on general relativity. The pair theorized the existence of an object called an Einstein-Rosen Bridge, a black hole from which nothing can escape, linked to a white hole, which nothing can enter, that spews out the material sucked into the black hole. Their ideas about particles and antiparticles being linked via a kind of space-time hosepipe never really worked out, but did inspire later work into the concept of wormholes.

The best minds in theoretical physics figured that, while wormholes might work as solutions to Einstein's mind-boggling equations, they would collapse too quickly for anyone to even attempt to travel through them.

However, new research by a team led by theoretical physicist Jose Luis Blázquez-Salcedo posits the possibility of travel through the wormhole without the need for, as yet theoretical, negative mass. This sounds fantastic. Humanity can now track one down and traverse the stars faster than our wildest dreams, right? Not so fast.

Another obscure abbreviation is taking the world by storm as speculators race to cash in, but not everyone is crazy about the new idea.

Non-fungible tokens (NFTs) have been generating a lot of attention and headlines in the tech world in recent weeks, leaving many intrigued by their potential and many more scratching their heads wondering what exactly they are.

They've been heralded as the future of art and music and potentially the next best investment since Bitcoin, but they're not without drawbacks.

So what are NFTs and are they here to stay?

The menagerie of bacterial and fungal species living among us is ever growing - and this is no exception in low-gravity environments, such as the International Space Station (ISS).

Researchers from the United States and India working with NASA have now discovered four strains of bacteria living in different places in the ISS - three of which were, until now, completely unknown to science.

Three of the four strains were isolated back in 2015 and 2016 - one was found on an overhead panel of the ISS research stations, the second was found in the Cupola, the third was found on the surface of the dining table; the fourth was found in an old HEPA filter returned to Earth in 2011.

Long-lost ice core provides direct evidence that giant ice sheet melted off within the last million years and is highly vulnerable to a warming climate, PNAS study shows.
In 1966, US Army scientists drilled down through nearly a mile of ice in northwestern Greenland — and pulled up a fifteen-foot-long tube of dirt from the bottom. Then this frozen sediment was lost in a freezer for decades. It was accidentally rediscovered in 2017.

In 2019, University of Vermont scientist Andrew Christ looked at it through his microscope — and couldn't believe what he was seeing: twigs and leaves instead of just sand and rock. That suggested that the ice was gone in the recent geologic past — and that a vegetated landscape, perhaps a boreal forest, stood where a mile-deep ice sheet as big as Alaska stands today.

Over the last year, Christ and an international team of scientists — led by Paul Bierman at UVM, Joerg Schaefer at Columbia University and Dorthe Dahl-Jensen at the University of Copenhagen — have studied these one-of-a-kind fossil plants and sediment from the bottom of Greenland. Their results show that most, or all, of Greenland must have been ice-free within the last million years, perhaps even the last few hundred-thousand years.

"Ice sheets typically pulverize and destroy everything in their path," says Christ, "but what we discovered was delicate plant structures — perfectly preserved. They're fossils, but they look like they died yesterday. It's a time capsule of what used to live on Greenland that we wouldn't be able to find anywhere else."

The discovery helps confirm a new and troubling understanding that the Greenland ice has melted off entirely during recent warm periods in Earth's history — periods like the one we are now creating with human-caused climate change.

Understanding the Greenland Ice Sheet in the past is critical for predicting how it will respond to climate warming in the future and how quickly it will melt. Since some twenty feet of sea-level rise is tied up in Greenland's ice, every coastal city in the world is at risk. The new study provides the strongest evidence yet that Greenland is more fragile and sensitive to climate change than previously understood — and at grave risk of irreversibly melting off.

"This is not a twenty-generation problem," says Paul Bierman, a geoscientist at UVM in the College of Arts & Sciences, Rubenstein School of Environment & Natural Resources, and fellow in the Gund Institute for Environment. "This is an urgent problem for the next 50 years."

The new research was published March 15 in the Proceedings of the National Academy of Sciences.

New simulations have identified the Karma family of asteroids in the main belt as a potential source of near-Earth asteroids.

When asteroids in the main belt of the solar system collide, the fragments come back together to form smaller rubble-pile bodies that orbit the Sun as a "family." Under the right conditions, some of those family members can end up in near-Earth space.
In a study published in Monthly Notices of the Royal Astronomical Society, researchers simulated the orbital evolution of asteroids in the Karma family, starting with the initial family-creating impact. The results suggest that over the family's lifetime, 350 members have transferred close to Earth's orbit — and around 10 might currently be in near-Earth space right now.

Lead author Dr Melandri Vlok from the Department of Anatomy, University of Otago, says this ground-breaking research, published today in Scientific Reports, changes the entire understanding of the relationship humans have had with malaria, still one of the deadliest diseases in the world.

"Until now we've believed malaria became a global threat to humans when we turned to farming, but our research shows in at least Southeast Asia this disease was a threat to human groups well before that.

"This research providing a new cornerstone of malaria's evolution with humans is a great achievement by the entire team," Dr Vlok says.