Viruses may be stealthy invaders, but a study at the Weizmann Institute of Science reveals a new, chatty side of some: for the first time, viruses have been found communicating with one another. This communication -- short "posts" left for kin and descendants -- helps the viruses reading them to decide how to proceed with the process of infection. The research was reported in Nature.

Many viruses face a choice after they have infected their hosts: to replicate quickly, killing the cell in the process, or to become dormant and lie in wait. HIV, herpes, and a number of other human viruses behave this way and, in fact, even the viruses that attack bacteria -- phages -- face similar decisions when invading a cell. What causes a virus to choose dormancy over immediate gratification? Prof. Rotem Sorek and his group in the Weizmann Institute's Department of Molecular Genetics have now discovered that, during infection, viruses secrete small molecules into their environment that other viruses can pick up and "read." In this way, they can actually coordinate their attack, turning simple messages into a fairly sophisticated strategy.

The Tusk was absolutely thrilled to see the publication last week of a paper concerning Carolina Bays in the distinguished journal, Geomorphology, A Model for the Geomorphology of Bays. Other than a brief role for the Carolina bays in the early papers of the Comet Research Group, and a much longer series of Geological Society of America posters laboriously researched and determinedly published by Michael Davias et. al, Zamora's journal article is the only peer-reviewed and published 'ET origin' work on bays in the last two decades — and it is a doozy.

Zamora builds on the modern work of Davias and David Kimbel, and Willam Prouty and Melton and Schriver of the first half of the 20th century, with an assist from Eyton and Parkhurst in the 70's. Each of the researchers maintained that the bays were formed at once by a barrage of material from the midwest. But, just as the early researchers ultimately decided, those alive today dismiss bays as direct impacts of ET fragments of a comet or asteroid, and consider them to be the remnant features of secondary impacts from the ejecta and ballistic shockwaves of northerly catastrophe. They are wise to do so. The correct theory must account for ALL the easily observed, unique characteristics of bays. [See list of 16 from Eyton and Parkhurst here] The "wind and wave," gradual formation, theories that continue to hold sway in classrooms and publications from Ivestor and Brooks fail miserably to account for all the observed phenomena, while Zamora checks each off with ease.

When Doug Wiens approached Minnesota farmers to ask permission to install a seismometer on their land, he often got a puzzled look. "You could tell they were thinking 'Why are you putting a seismometer here?,' " said Wiens, professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis. "'We don't have earthquakes and we don't have volcanoes. Do you know something we don't?' "

Actually, he did. Deep beneath the fertile flat farmland, there is a huge scar in the Earth called the Midcontinent Rift. This ancient and hidden feature bears silent witness to a time when the core of what would become North America nearly ripped apart. If the U-shaped rip had gone to completion, the land between its arms — including at least half of what is now called the Midwest — would have pulled away from North America, leaving a great ocean behind.

Despite it's 'Red Planet' moniker, Mars is looking pretty frosty. The planet is experiencing an extensive build-up of frost on its north pole, the magnitude of which can be seen in the European Space Agency's (ESA) new timelapse video.

The images were taken by a high-res camera onboard the ESA's Mars Express between November 23 and December 30, 2004. When run together, the images show the build-up of frost in a 73x41km (45x25 mile) section of the red planet's north polar ice cap.

Mars is located about 50 million miles farther away from the sun than Earth so, while it's 'Red Planet' nickname may suggest a warm climate, the surface is actually comprised mostly of layers of water-ice - which can build to a depth of 2km around its north pole.

The regulator has suggested that it treat every edit of an animal's genome like a new drug, but some scientists think it could slow progress.

If newly proposed U.S. Food and Drug Administration regulations were to go into practice, research labs around the U.S. could find it harder to pursue their work editing the genomes of animals.

Gene-editing of animals, one of our 10 Breakthrough Technologies in 2014, is already underway in many labs around the world. Researchers have used the CRISPR-Cas9 technique, for instance, to heal mice of muscular dystrophy, breed extra-muscular beagles, and create hornless cows (they're safer to farm).

Summary: Stress may impede perceptual learning and performance, a new study reports.

Stress is part of our everyday lives - while some thrive on it, it makes others sick. But what does stress do to our senses?

When we train them, we can sharpen our senses thereby improve our perceptual performance. The stress hormone cortisol completely blocks this important ability. In the current issue of "Psychoneuroendocrinology" neuroscientists of the Ruhr University Bochum (RUB) report on this finding.

The Cassini spacecraft has captured the closest ever view of Saturn's small, 'wavemaker,' moon, Daphnis, allowing astronomers to observe new details up close.

The image is the latest in a series of spectacular pictures of Saturn's rings and moons sent back by the spacecraft.

Daphnis is about five miles (8 kilometres) in diameter and orbits Saturn in the 26-mile (42-kilometer) wide Keeler Gap within the A ring - the outermost of the large bright rings.

In this image, taken by the Cassini narrow-angle camera, however, the gap appears smaller due to the spacecraft's viewing angle.

A new study published in the peer-reviewed journal Space Weather reports the discovery of radiation "clouds" at aviation altitudes. When airplanes fly through these clouds, dose rates of cosmic radiation normally absorbed by air travelers can double or more.

"We have flown radiation sensors onboard 264 research flights at altitudes as high as 17.3 km (56,700 ft) from 2013 to 2017," says Kent Tobiska, lead author of the paper and PI of the NASA-supported program Automated Radiation Measurements for Aerospace Safety (ARMAS). "On at least six occasions, our sensors have recorded surges in ionizing radiation that we interpret as analogous to localized clouds."

The fact that air travelers absorb radiation is not news. Researchers have long known that cosmic rays crashing into Earth's atmosphere create a spray of secondary particles such as neutrons, protons, electrons, X-rays and gamma-rays that penetrate aircraft. 100,000 mile frequent flyers absorb as much radiation as 20 chest X-rays—and even a single flight across the USA can expose a traveler to more radiation than a dental X-ray.

Conventional wisdom says that dose rates should vary smoothly with latitude and longitude and the height of the aircraft. Any changes as a plane navigates airspace should be gradual. Tobiska and colleagues have found something quite different, however: Sometimes dose rates skyrocket for no apparent reason.

"We were quite surprised to see this," says Tobiska.

A pair of researchers affiliated with the Natural History Museum in Chemnitz and Technische Universität Bergakademie Freiberg, both in Germany, has found evidence in ancient tree rings of a solar sunspot cycle millions of years ago similar to the one observed in more modern times. In their paper published in the journal Geology, Ludwig Luthardt and Ronny Rößler describe how they gathered an assortment of petrified tree samples from a region in Germany and used them to count sunspot cycles.

Scientists know that the sun undergoes a sunspot cycle of approximately 11 years—some spots appear, grow cooler and then slowly move toward the equator and eventually disappear—the changes to the sun spots cause changes to the brightness level of the sun—as the level waxes and wanes, plants here on Earth respond, growing more or less in a given year—this can be seen in the width of tree rings. In this new effort, the researchers gathered petrified tree samples from a region of Germany that was covered by lava during a volcanic eruption approximately 290 million years ago (during the Permian period), offering a historical record of sun activity.

The research pair obtained 43 petrified tree specimens (tree-trunk slices) and report that they were able to count 1,917 rings which were preserved well enough to allow for observation under a microscope. Because the trees had all died at the same time, the researchers were able to establish a baseline between them which allowed for comparing tree ring growth between samples over the same time periods—which covered 79 years. Doing so, they report, revealed very clearly a cycle of growth similar to that seen in modern trees, though in this case, it was slightly different. Today the cycle is an average of 11.2 years, back then it was 10.6—close enough, the researchers suggest, to conclude that the sun has been behaving very predictably for at least 290 million years.

It should be noted that not everyone agrees with the theory that sunspot activity leaves such a clear record in tree rings—other factors might be involved such as general global temperature, weather patterns or even outbreaks of insect populations.

More information: Ludwig Luthardt et al. Fossil forest reveals sunspot activity in the early Permian, Geology(2017)

Perceived existential threats posed to humanity by artificial intelligence (AI) are "uninformed," a US Department of Defense report has concluded - although some still harbor grave reservations about the technology's potential.

Perspectives on Research in Artificial Intelligence and Artificial General Intelligence Relevant to DoD, authored by a group of independent scientists belonging to JASON, the secretive organization that counsels the US government on sensitive scientific matters, states growing public suspicion of AI is "not always based on fact," especially in respect of military technologies.

Noting that in January 2015 Elon Musk, founder of space transport services company SpaceX and chief product architect at Tesla Motors, declared AI the "biggest existential threat" to the survival of the human race, the report suggests alleged hazards do not cohere with the current research directions of AI. Instead, they "spring from dire predictions about one small area of research within AI, Artificial General Intelligence."

AGI relates to the development of machines capable of long-term decision-making and intent, akin to real human beings.