Before 2020, evidence for the efficacy of community masking - that is, asking ordinary members of the public to wear cloth or surgical masks when going about their business - was shaky at best.

This evidence was reviewed in detail by Jeffrey Anderson, a former director of the Bureau of Justice Statistics. He notes that:

of the 14 RCTs that have tested the effectiveness of masks in preventing the transmission of respiratory viruses, three suggest, but do not provide any statistically significant evidence in intention-to-treat analysis, that masks might be useful. The other eleven suggest that masks are either useless — whether compared with no masks or because they appear not to add to good hand hygiene alone — or actually counterproductive.

The US military's secretive R&D wing has announced a successful flight test for a hypersonic missile system developed by Raytheon, after a previous trial using Lockheed Martin's rival model ended in failure last year.

The free-flight launch for the Hypersonic Air-breathing Weapon Concept (HAWC) was conducted successfully last week and met "all primary test objectives," the Defense Advanced Research Projects Agency (DARPA) said in a press release on Monday. It was the first successful test of the system made public by the military.

"This brings us one step closer to transitioning HAWC to a program of record that offers next generation capability to the US military," said Andrew Knoedler, who heads the HAWC program in DARPA's Tactical Technology Office, adding that the test "was a successful demonstration of the capabilities that will make hypersonic cruise missiles a highly effective tool for our warfighters."

Like the speed of an advancing race car driver, the winds in the outermost "lane" of Jupiter's Great Red Spot are accelerating - a discovery only made possible by NASA's Hubble Space Telescope, which has monitored the planet for more than a decade.

Researchers analyzing Hubble's regular "storm reports" found that the average wind speed just within the boundaries of the storm, known as a high-speed ring, has increased by up to 8 percent from 2009 to 2020. In contrast, the winds near the red spot's innermost region are moving significantly more slowly, like someone cruising lazily on a sunny Sunday afternoon.

The massive storm's crimson-colored clouds spin counterclockwise at speeds that exceed 400 miles per hour - and the vortex is bigger than Earth itself. The red spot is legendary in part because humans have observed it for more than 150 years.

"When I initially saw the results, I asked 'Does this make sense?' No one has ever seen this before," said Michael Wong of the University of California, Berkeley, who led the analysis published today in Geophysical Research Letters. "But this is something only Hubble can do. Hubble's longevity and ongoing observations make this revelation possible."

New research from Washington University School of Medicine in St. Louis suggests that radiation therapy can reprogram heart muscle cells to what appears to be a younger state, fixing electrical problems that cause a life-threatening arrhythmia without the need for a long-used, invasive procedure.

In that invasive procedure — catheter ablation — a catheter is threaded into the heart, and the tissue that triggers the life-threatening irregular heart rhythm — ventricular tachycardia — is burned, creating scars that block the errant signals. The new study, however, shows that noninvasive radiation therapy normally used to treat cancer can reprogram the heart muscle cells to a younger and perhaps healthier state, fixing the electrical problem in the cells themselves without needing scar tissue to block the overactive circuits. The study also suggests that the same cellular reprogramming effect could be achieved with lower doses of radiation, opening the door to the possibility of wider uses for radiation therapy in different types of cardiac arrhythmias.

The study appears Sept. 24 in the journal Nature Communications.

Physician-scientists at Washington University showed in 2017 that radiation therapy typically reserved for cancer treatment could be directed at the heart to treat ventricular tachycardia.

In recent articles, I have summarized lectures at CELS (Conference on Engineering in Living Systems) that described an engineering model for adaptation and explained how adaptation derives from organisms' internal capacities (here, link). Now I will summarize another CELS lecture that expanded upon these themes by outlining a second complementary engineering model for adaptation.

Comparing Models

Standard evolutionary theory assumes that genetic variation expands through DNA mutating or otherwise altering randomly. Concurrently, natural selection and other processes transform species over time gradually through numerous, successive, slight modifications. The results are unpredictable, and in different subpopulations they can vary greatly.

NASA's Mars InSight lander has detected its three most powerful quakes yet.

On 25 August, InSight detected two quakes, at magnitude 4.1 and 4.2. Then, on 18 September - the lander's 1,000th Mars day of operation - it picked up the rumbles of another magnitude 4.2 quake.

These new quakes blow the previous record of a magnitude 3.7 quake detected in 2019 out of the water. Fascinatingly, the largest of the August quakes was the most distant detected yet, with an epicenter some 8,500 kilometers (5,280 miles) from InSight.

Analysis is still ongoing, but scientists are excited about the possibility of learning something new about the interior of the red planet.

Using mathematical models, a quartet of Chinese scientists has argued that the first case of Covid-19 appeared between April and November 2019 in the northeastern US, long before the outbreak in Wuhan, China.

"The calculation results show that the COVID-19 epidemic in the United States has a high probability of beginning to spread around September 2019," says the 14-page paper published on Wednesday at ChinaXiv, a repository operated by the National Science Library of the Chinese Academy of Sciences.

The quartet set out to "infer the origin time of pandemic" based on "a data and model hybrid driven method." They modeled the positive test rate to fit the actual trends and used "the least squares estimation to obtain the optimal model parameters," before applying the "kernel density estimation...to infer the origin time of pandemic given the specific confidence probability," according to the paper.

Officially, the first case of Covid-19 was registered in the US on January 20, 2020 - about a month after the outbreak in the Chinese city of Wuhan. The Chinese researchers, however, argue that there is a 50% probability of first cases in 11 US states and the District of Columbia prior to that - as early as April 2019 in Rhode Island and as late as November that year in Delaware.

Much of the paper focuses on Maryland, the location of Fort Detrick - a US Army base used to research bioweapons during the Cold War, and now hosts the US biological defense program.

Northwestern University engineers have added a new capability to electronic microchips: flight.

About the size of a grain of sand, the new flying microchip (or "microflier") does not have a motor or engine. Instead, it catches flight on the wind — much like a maple tree's propeller seed — and spins like a helicopter through the air toward the ground.

By studying maple trees and other types of wind-dispersed seeds, the engineers optimized the microflier's aerodynamics to ensure that it — when dropped at a high elevation — falls at a slow velocity in a controlled manner. This behavior stabilizes its flight, ensures dispersal over a broad area and increases the amount of time it interacts with the air, making it ideal for monitoring air pollution and airborne disease.

As the smallest-ever human-made flying structures, these microfliers also can be packed with ultra-miniaturized technology, including sensors, power sources, antennas for wireless communication and embedded memory to store data.

The research is featured on the cover of the Sept. 23 issue of Nature.

A relatively new type of computing that mimics the way the human brain works was already transforming how scientists could tackle some of the most difficult information processing problems.

Now, researchers have found a way to make what is called reservoir computing work between 33 and a million times faster, with significantly fewer computing resources and less data input needed.

In fact, in one test of this next-generation reservoir computing, researchers solved a complex computing problem in less than a second on a desktop computer.

Using the now current state-of-the-art technology, the same problem requires a supercomputer to solve and still takes much longer, said Daniel Gauthier, lead author of the study and professor of physics at The Ohio State University.

"We can perform very complex information processing tasks in a fraction of the time using much less computer resources compared to what reservoir computing can currently do," Gauthier said.

"And reservoir computing was already a significant improvement on what was previously possible."

The study was published today (Sept. 21, 2021) in the journal Nature Communications.

Reservoir computing is a machine learning algorithm developed in the early 2000s and used to solve the "hardest of the hard" computing problems, such as forecasting the evolution of dynamical systems that change over time, Gauthier said.

Dynamical systems, like the weather, are difficult to predict because just one small change in one condition can have massive effects down the line, he said.

One famous example is the "butterfly effect," in which - in one metaphorical example - changes created by a butterfly flapping its wings can eventually influence the weather weeks later.

Previous research has shown that reservoir computing is well-suited for learning dynamical systems and can provide accurate forecasts about how they will behave in the future, Gauthier said.

A study published in the journal Geology rules out that extreme volcanic episodes had any influence on the massive extinction of species in the late Cretaceous. The results confirm the hypothesis that it was a giant meteorite impact what caused the great biological crisis that ended up with the non-avian dinosaur lineages and other marine and terrestrial organisms 66 million years ago.

The study was carried out by the researcher Sietske Batenburg, from the Faculty of Earth Sciences of the University of Barcelona, and the experts Vicente Gilabert, Ignacio Arenillas and José Antonio Arz, from the University Research Institute on Environmental Sciences of Aragon (IUCA-University of Zaragoza).

K/Pg boundary: the great extinction of the Cretaceous in Zumaia coasts

The scenario of this study were the Zumaia cliffs (Basque Country), which have an exceptional section of strata that reveals the geological history of the Earth in the period of 115-50 million years ago (Ma). In this environment, the team analyzed sediments and rocks that are rich in microfossils that were deposited between 66.4 and 65.4 Ma, a time interval that includes the known Cretaceous/Paleogene boundary (K/Pg). Dated in 66 Ma, the K/Pg boundary divides the Mesozoic and Cenozoic eras and it coincides with one of the five large extinctions of the planet.

This study analysed the climate changes that occurred just before and after the massive extinction marked by the K/Pg boundary, as well as its potential relation to this large biological crisis. For the first time, researchers examined whether this climate change coincides on the time scale with its potential causes: the Deccan massive volcanism (India) ─one of the most violent volcanic episodes in the geological history of the planet─ and the orbital variations of the Earth.

"The particularity of the Zumaia outcrops lies in that two types of sediments accumulated there ─some richer in clay and others richer in carbonate─ that we can now identify as strata or marl and limestone that alternate with each other to form rhythms", notes the researcher Sietske Batenburg, from the Department of Earth and Ocean Dynamics of the UB. "This strong rhythmicity in sedimentation is related to cyclical variations in the orientation and inclination of the Earth axis in the rotation movement, as well as in the translational movement around the Sun".

These astronomic configurations ─the known Milankovitch cycles, which repeat every 405,000, 100,000, 41,000 and 21,000 years─, regulate the amount of solar radiation they receive, modulate the global temperature of our planet and condition the type of sediment that reaches the oceans. "Thanks to these periodicities identified in the Zumaia sediments, we have been able to determine the most precise dating of the climatic episodes that took place around the time when the last dinosaurs lived", says PhD student Vicente Gilabert, from the Department of Earth Sciences at UZ, who will present his thesis defence by the end of this year.