Scientists have gone back and forth over exactly what caused a mass extinction event 66 million years ago, which destroyed about 75% of all life on Earth, including all of the large dinosaurs. Some have thought that volcanic activity could be to blame, but one new study shows that a giant asteroid impact was the prime culprit. Space.com reports: In a new study, researchers from Imperial College London, the University of Bristol and University College London have shown that the asteroid impact, not volcanic activity, was the main reason that about 75% of life on Earth perished at that time, and it did so by significantly interfering with Earth's climate and ecosystems. To come to this conclusion, the researchers modeled how Earth's climate would be expected to respond to two separate possible extinction causes: volcanism and asteroid impact. In these mathematical models, they included environmental factors including rainfall and temperature, which would have been critical to the survival of these species. They also included the presence of sunlight-blocking gases and particles and carbon dioxide, a greenhouse gas. With these models, the team found that the giant asteroid hitting our planet would have released tremendous amounts of gas and particles into Earth's atmosphere, blocking out the sun for years on end. This effect would have created a sort of semi-permanent winter on Earth, making the planet unlivable for most of its inhabitants.

Now, while the team found the asteroid impact to be the major factor in making Earth unlivable for most animals, they also found that volcanic activity could have actually helped life to recover over time, a conclusion that scientists have drawn before. They found that, while volcanoes do release sunlight-blocking gases and particles, which would have helped to block the sun in the short term, they also release large amounts of carbon dioxide which, because it's a greenhouse gas, would have built up in the atmosphere and warmed the planet. So, as the researchers suggest in this work, while the devastating winter caused by the asteroid killed off most life on Earth, over time, the warming effect created from the volcanic greenhouse gases could have helped to restore life to habitats. The study has been published in the journal Proceedings of the National Academy of Sciences.

An anonymous reader quotes a report from CNBC: White House coronavirus advisor Dr. Anthony Fauci said Tuesday that U.S. health officials are keeping an eye on a new strain of flu carried by pigs in China that has characteristics of the 2009 H1N1 virus and 1918 pandemic flu. The virus, which scientists are calling "G4 EA H1N1," has not yet been shown to infect humans but it is exhibiting "reassortment capabilities," Fauci, director of the National Institute of Allergy and Infectious Diseases, told the Senate Health, Education, Labor and Pensions Committee during a hearing.

"In other words, when you get a brand new virus that turns out to be a pandemic virus it's either due to mutations and/or the reassortment or exchanges of genes," he told lawmakers. "And they're seeing virus in swine, in pigs now, that have characteristics of the 2009 H1N1, of the original 1918, which many of our flu viruses have remnants of that in it, as well as segments from other hosts, like swine." Fauci said Tuesday there's always "the possibility that you might have another swine flu-type outbreak as we had in 2009." "It's something that still is in the stage of examination," he said. It's not "an immediate threat where you're seeing infections, but it's something we need to keep our eye on, just the way we did in 2009 with the emergence of the swine flu."

swell shares the findings from a small pilot study that suggests a few minutes of looking into a deep red light could have a dramatic effect on preventing eyesight decline as we age. CNN reports: Researchers recruited 12 men and 12 women, whose ages ranged from 28 to 72. Each participant was given a small handheld flashlight that emitted a red light with a wavelength of 670 nanometers. That wavelength is toward the long end of the visible spectrum, and just short of an infrared wavelength, which tends to be invisible to the human eye. They spent three minutes each day looking into the light over a period of two weeks. The lights work on both cones and rods in the eye. Cones are photo receptor cells that detect color and work best in well-lit situations. Rods, which are much more plentiful, are retina cells that specialize in helping us see in dim light, according to the American Academy of Ophthalmology.

Researchers measured the cone function in subjects' eyes by having them identify colored letters with low contrast. And they measured their eyes' rod sensitivity by asking them to detect light signals in the dark. There was a 14% improvement in the ability to see colors, or cone color contrast sensitivity, for the entire two dozen participants. Improvement, however, was most significant in study participants over age 40. For those ages, cone color contrast sensitivity rose by 20% over the course of the study. That age bracket also saw significant increases in rod threshold, which corresponds to the ability to see in low light. Study participants under 40 also experienced some improvement, but didn't see the same jump as older subjects. Younger eyes haven't declined as much as older eyes.

An anonymous reader quotes a report from The Washington Post: After a late-spring lull, daily coronavirus cases in the United States have again hit record highs, driven by resurgent outbreaks in states such as Florida, Arizona and California. Hospitals in Houston are already on the brink of being overwhelmed, and public health experts worry the pandemic's body count will soon again be climbing in tandem with the daily case load. The dire situation has raised the specter of another round of state-level stay-at-home orders to halt the pandemic's spread and caused a number of governors to pause or reverse their ongoing reopening plans. Against this backdrop, a team of economists at investment bank Goldman Sachs has published an analysis suggesting more painful shutdowns could be averted if the United States implements a nationwide mask mandate.

"A face mask mandate could potentially substitute for lockdowns that would otherwise subtract nearly 5% from GDP," the team, led by the company's chief economist, Jan Hatzius, writes. It's worth noting the authors of the report are economists and not public health experts. Their primary motivation is to protect the economic interests of Goldman Sachs's investors, which is why they're interested in the effects of federal policy on gross domestic product. But their findings are in line with a number of other published studies on the efficacy of masks. The Goldman Sachs report notes the United States is a global outlier with respect to face mask use, which is widespread in Asia and currently mandated in many European countries. Though the Centers for Disease Control and Prevention "recommends" the use of masks in public and 20 states plus the District of Columbia have implemented their own mandates, there is no binding national policy, with wide regional variations in mask use around the country. "We estimate that statewide mask mandates gradually raise the percentage of people who 'always' or 'frequently' wear masks by around 25 [percentage points] in the 30+ days after signing," the authors write. "Our numerical estimates are that cumulative cases grow 17.3% per week without a mask mandate but only 7.3% with a mask mandate, and that cumulative fatalities grow 29% per week without a mask mandate but only 16% with a mask mandate."

shirappu writes: A new paper by Disney Research shows off a newly developed neural network that can swap faces in photos and videos at high-resolution. The idea behind this technology is to replace an actor's performance with a different actor's face, or for roles that require de-aging or increasing age, or for portraying actors who have passed away. Current face-swapping technology (also known as deepfakes) often creates an "uncanny valley" effect, where something about the image or video feels off. Though there is some of that in Disney Research's tech, it's still a huge step forward for creating believable face-swapping in the entertainment industry. This has once again brought up a conversation around the ethical use of this technology and the potential for malicious use. However, given the amount of ongoing R&D in this area, it seems unlikely that we'll see any slowdown in the near future.

schwit1 writes: Same vaccine being tested in Canada. But China just skipped ahead and approved it for one year for its soldiers without full long-term data. The COVID-19 vaccine (Ad5-nCoV) in question is developed by China's Academy of Military (AMS) research unit and CanSino Biologics. Clinical trials proved it was safe and showed some efficacy, according to the company.

Reuters says the company has not disclosed whether the inoculation of the vaccine candidate is mandatory or optional, citing commercial secrets. "AMS received an approval earlier this month to test its second experimental coronavirus vaccine in humans," adds Reuters.

A new strain of flu which has the potential to become pandemic has been identified in China by scientists. From a report: It emerged recently and is carried by pigs, but can infect humans, they say. The researchers are concerned that it could mutate further so that it can spread easily from person to person, and trigger a global outbreak. They say it has "all the hallmarks" of being highly adapted to infect humans - and needs close monitoring. As it's new, people could have little or no immunity to the virus. A bad new strain of influenza is among the top disease threats that experts are watching for, even as the world attempts to bring to an end the current coronavirus pandemic. The last pandemic flu the world encountered - the swine flu outbreak of 2009 that began in Mexico - was less deadly than initially feared, largely because many older people had some immunity to it, probably because of its similarity to other flu viruses that had circulated years before.

The global total of deaths passed 500,000 on Sunday, while the number of confirmed cases surpassed 10 million. From a report: The grim markers were hit as countries around the world struggle to keep new infections from reaching runaway levels while simultaneously trying to emerge from painful lockdowns. In April, roughly a month after the World Health Organization declared the outbreak a pandemic, deaths topped 100,000. In early May, the figure climbed to 250,000. Now it has doubled in less than two months. More than a quarter of all known deaths have been in the United States. The number of confirmed infections -- which took about 40 days to double -- may be substantially underestimated, public health officials say. Data released last week by the Centers for Disease Control and Prevention indicated that the actual figures in many regions are probably 10 times as high as reported.

"What if a single injection could lower blood levels of cholesterol and triglycerides — for a lifetime?" asks the New York Times.

"In the first gene-editing experiment of its kind, scientists have disabled two genes in monkeys that raise the risk for heart disease." (Alternate source here.) Humans carry the genes as well, and the experiment has raised hopes that a leading killer may one day be tamed. "This could be the cure for heart disease," said Dr. Michael Davidson, director of the Lipid Clinic at the University of Chicago Pritzker School of Medicine, who was not involved in the research.

But it will be years before human trials can begin, and gene-editing technology so far has a mixed tracked record. It is much too early to know whether the strategy will be safe and effective in humans; even the monkeys must be monitored for side effects or other treatment failures for some time to come. The results were presented on Saturday at the annual meeting of the International Society for Stem Cell Research, this year held virtually with about 3,700 attendees around the world. The scientists are writing up their findings, which have not yet been peer-reviewed or published...

Both genes are active in the liver, which is where cholesterol and triglycerides are produced. People who inherit mutations that destroyed the genes' function do not get heart disease.

"Invisible outbreaks sprang up everywhere. The United States ignored the warning signs," writes the New York Times, in a detailed interactive data visualization.

"We analyzed travel patterns, hidden infections and genetic data to show how the epidemic spun out of control." By mid-February, there were only 15 known coronavirus cases in the United States, all with direct links to China... The patients were isolated. Their contacts were monitored. Travel from China was restricted.

None of that worked. Only a small part of the picture was visible. Some 2,000 hidden infections were already spreading through major cities...

Genetic samples linked to the Seattle outbreak appeared in at least 14 states, said Trevor Bedford, a professor at Fred Hutchinson Cancer Research Center... In New York City, where officials had found only a single case by March 1, roughly 10,000 infections had spread undetected... More than 5,000 contagious travelers left New York City in the first two weeks of March, estimates suggest... People [from New York City] also made more than 25,000 trips to New Orleans, where genetic data suggests that a large early outbreak stemmed from infections from New York...

Travel from the city helped to spread that variant across the country. "New York has acted as a Grand Central Station for this virus," said David Engelthaler of the Translational Genomics Research Institute. By the time President Trump blocked travel from Europe on March 13, the restrictions were essentially pointless. The outbreak had already been spreading widely in most states for weeks... The New Orleans outbreak helped seed infection across Louisiana and the South...

Even now, America remains in the dark. Most infected people are never tested. There is little capacity to trace and isolate the contacts to those who do test positive.

After the lockdowns expired, new cases spiked once again.

Long-time Slashdot reader hankwang writes: The New York Times has an article on how the transmission of Covid-19 by seemingly healthy individuals was discovered in Germany on January 27, but the report was discredited because of a quibble over whether it was really asymptomatic or rather presymptomatic or oligosymptomatic transmission. Oligosymptomatic means that the symptoms are so mild that they are not recognized as symptoms... It took until March before asymptomatic transmission was publicly acknowledged as playing a significant role.
From the article. (Alternate source here): Dr. Rothe, an infectious disease specialist at Munich University Hospital, and her colleagues were among the first to warn the world [on January 30]. But even as evidence accumulated from other scientists, leading health officials expressed unwavering confidence that symptomless spreading was not important. In the days and weeks to come, politicians, public health officials and rival academics disparaged or ignored the Munich team. Some actively worked to undermine the warnings at a crucial moment, as the disease was spreading unnoticed...

It is now widely accepted that seemingly healthy people can spread the virus, though uncertainty remains over how much they have contributed to the pandemic. Though estimates vary, models using data from Hong Kong, Singapore and China suggest that 30 to 60 percent of spreading occurs when people have no symptoms... The Chinese health authorities had explicitly cautioned that patients were contagious before showing symptoms. A Japanese bus driver was infected while transporting seemingly healthy tourists from Wuhan. And by the middle of February, 355 people aboard the Diamond Princess cruise ship had tested positive. About a third of the infected passengers and staff had no symptoms...

[P]ublic health officials saw danger in promoting the risk of silent spreaders. If quarantining sick people and tracing their contacts could not reliably contain the disease, governments might abandon those efforts altogether... Plus, preventing silent spreading required aggressive, widespread testing that was then impossible for most countries. "It's not like we had some easy alternative," said Dr. Libman, the Canadian doctor. "The message was basically: 'If this is true, we're in trouble.'" European health officials say they were reluctant to acknowledge silent spreading because the evidence was trickling in and the consequences of a false alarm would have been severe...

As the research coalesced in March, European health officials were convinced. "OK, this is really a big issue," Dr. Agoritsa Baka, a senior European Union doctor, recalled thinking. "It plays a big role in the transmission..." Since then, the C.D.C., governments around the world and, finally, the World Health Organization have recommended that people wear masks in public.

Sweden's population is not quite twice the size of Norway's — yet Sweden has reported 21 times as many deaths from Covid-19, prompting many countries to close their borders to Sweden, reports the New York Times: Norway isn't the only Scandinavian neighbor barring Swedes from visiting this summer. Denmark and Finland have also closed their borders to Swedes, fearing that they would bring new coronavirus infections with them. While those countries went into strict lockdowns this spring, Sweden famously refused, and now has suffered roughly twice as many infections and five times as many deaths as the other three nations combined, according to figures compiled by The New York Times. While reporting differences can make comparisons inexact, the overall trend is clear, as is Sweden's new status as Scandinavia's pariah state...

"When you see 5,000 deaths in Sweden and 230 in Norway, it is quite incredible," said Gro Harlem Brundtland, a former prime minister of Norway and the former director of the World Health Organization, during a digital lecture at the Norwegian Academy of Science and Letters in May...

Swedes now find themselves with few options for moving about the European Union. Most countries in the bloc have reopened their borders to member nations, but only France, Italy, Spain and Croatia are welcoming Swedes without restrictions.
On a popular Scandinavian radio program, a journalist with a leading Swedish paper complained about how Sweden was being treated by its neighboring countries, according to the Times. "We are supposed to sit here in our corner of shame, and the worst part is that you're savoring it."

The BBC notes that just days later, on Wednesday, Sweden reported 1,610 new infections — roughly one infection for every 6,354 people in Sweden and its highest number of daily infections since the outbreak began.

A suite of experiments that use the gene-editing tool CRISPR-Cas9 to modify human embryos have revealed how the process can make large, unwanted changes to the genome at or near the target site. Nature reports: The first preprint was posted online on June 5 by developmental biologist Kathy Niakan of the Francis Crick Institute in London and her colleagues. In that study, the researchers used CRISPR-Cas9 to create mutations in the POU5F1 gene, which is important for embryonic development. Of 18 genome-edited embryos, about 22% contained unwanted changes affecting large swathes of the DNA surrounding POU5F1. They included DNA rearrangements and large deletions of several thousand DNA letters -- much greater than typically intended by researchers using this approach. Another group, led by stem-cell biologist Dieter Egli of Columbia University in New York City, studied embryos created with sperm carrying a blindness-causing mutation in a gene called EYS2. The team used CRISPR-Cas9 to try to correct that mutation, but about half of the embryos tested lost large segments of the chromosome -- and sometimes the entire chromosome -- on which EYS is situated. And a third group, led by reproductive biologist Shoukhrat Mitalipov of Oregon Health & Science University in Portland, studied embryos made using sperm with a mutation that causes a heart condition. This team also found signs that editing affected large regions of the chromosome containing the mutated gene.

The three studies offered different explanations for how the DNA changes arose. Egli and Niakan's teams attributed the bulk of the changes observed in their embryos to large deletions and rearrangements. Mitalipov's group instead said that up to 40% of the changes it found were caused by a phenomenon called gene conversion, in which DNA-repair processes copy a sequence from one chromosome in a pair to heal the other. Mitalipov and his colleagues reported similar findings in 2017, but some researchers were skeptical that frequent gene conversions could occur in embryos. They noted that the maternal and paternal chromosomes are not next to each other at the time the gene conversion is postulated to occur, and that the assays the team used to identify gene conversions could have been picking up other chromosomal changes, including deletions. Egli and his colleagues directly tested for gene conversions in their latest preprint and failed to find them, and Burgio points out that the assays used in the Mitalipov preprint are similar to those the team used in 2017. One possibility is that DNA breaks are healed differently at various positions along the chromosome, says Jin-Soo Kim, a geneticist at Seoul National University and a co-author of the Mitalipov preprint.

Long-time Slashdot reader PCM2 shares a report from CBS News: Gov. Gavin Newsom on Thursday announced a new COVID-19 modeling website as well as new open-source tools designed to help California residents understand the data informing local health departments and empower what he called "citizen scientists." The governor introduced the new coronavirus modeling website [...] as a way for residents to see the raw data that is driving the decisions of state and county officials with full transparency.

The new website features three sections: a "Nowcast" section that provides the most current information on how fast COVID-19 is spreading in the state and by county; a "Forecasts" section that provides short-term COVID-19 forecasts in the state and by county; and a "Scenarios" section that projects the possible long-term impacts under different scenarios and responses to COVID-19, again for the whole state and by county. "We want to open up our site to 'netizen-tists' ... of citizen-scientists, people that are out there doing coding every single day," said Newsom. "We want to give them access through an open-source platform to all of the available data that we have, that I have, that our health professionals have, in a way that we don't believe has been done before anywhere in the United States. This is a deep dive for transparency and openness. This is a new resource that we are making available today."

Space tourism company Space Adventures announced a deal on Thursday with the S.P. Korolev Rocket and Space Corporation to fly two space tourists to the International Space Station. What makes this contract an eye-opener is that it would give one of the tourists an opportunity to go for a spacewalk outside the ISS. CNET reports: Space Adventures said this person would become "the first private citizen in history to experience open space." The S.P. Korolev Rocket and Space Corporation (known as Energia) makes the Soyuz equipment for Russia's space agency Roscosmos, which confirmed the Space Adventures agreement on Thursday. Roscosmos is targeting the flight for 2023.

The spacewalking tourist won't be sent out of the air hatch alone. A professional cosmonaut will go along. The spacewalk will also call for quite a bit of prep work. "Accepted and secured candidates will be required to complete specialized training and additional simulations in preparation for the spacewalk attempt," Space Adventures said. The flight will take place using a Russian Soyuz spacecraft, and the spacewalk participant will stay at the Russian segment of the station for 14 days.

Nearly 25 million Americans may have contracted the coronavirus, a figure 10 times higher than the number of confirmed cases, the Centers for Disease Control and Prevention (CDC) said Thursday. The Hill reports: In a briefing with reporters Thursday, CDC Director Robert Redfield said surveys of blood samples taken from around the country suggest that millions of Americans may have contracted the virus either without knowing it or with only minimal symptoms. For every one confirmed case, Redfield said, the CDC estimates that 10 more people have been infected. "This virus causes so much asymptomatic infection," Redfield said. "We probably recognized about 10 percent of the outbreak."

Almost 2.4 million Americans have tested positive for the coronavirus, according to the Center for Systems Science and Engineering at the Johns Hopkins University of Medicine. Redfield said the serological surveys of blood samples, collected both for coronavirus tests and for other reasons like blood donations or laboratory tests, showed that between 5 percent and 8 percent of Americans have contracted the virus. Most people who contract the SARS-CoV-2 virus show few if any symptoms, and only a small percentage require hospitalization. But while the number of potentially infected people is multitudes higher than the number of confirmed cases, Redfield also said the relatively low percentage of Americans who have been infected means hundreds of millions more remain at risk.

An anonymous reader quotes a report from CBS News: Alarming heat scorched Siberia on Saturday as the small town of Verkhoyansk (67.5N latitude) reached 100.4 degrees Fahrenheit, 32 degrees above the normal high temperature. If verified, this is likely the hottest temperature ever recorded in Siberia and also the hottest temperature ever recorded north of the Arctic Circle, which begins at 66.5 degrees North. The town is 3,000 miles east of Moscow and further north than even Fairbanks, Alaska. On Friday, the city of Caribou, Maine, tied an all-time record at 96 degrees Fahrenheit and was once again well into the 90s on Saturday. To put this into perspective, the city of Miami, Florida, has only reached 100 degrees one time since the city began keeping temperature records in 1896.

Verkhoyansk is typically one of the coldest spots on Earth. This past November, the area reached nearly 60 degrees Fahrenheit below zero, one of the first spots to drop that low in the winter of 2019-2020. Reaching 100 degrees in or near the Arctic is almost unheard of. Although the reading is questionable, back in 1915 the town of Fort Yukon, Alaska, not quite as far north as Verkhoyansk, is reported to have reached near 100 degrees. And in 2010 a town a few miles south of the Arctic circle in Russia reached 100. As a result of the hot-dry conditions right now, numerous fires rage nearby, and smoke is visible for thousands of miles on satellite images.

sciencehabit shares a report from Science Magazine: Gravitational wave detectors have spotted a cosmic collision in which a giant black hole swallowed up a mystery object seemingly too heavy to be a neutron star, but too light to be a black hole. Weighing in at 2.6 times the mass of the Sun, the object falls into a hypothetical "mass gap," a desert between the heaviest neutron star and the lightest black hole that some theories predict -- suggesting the gap doesn't exist and that those theories need to be amended. The data come from physicists working with the Laser Interferometer Gravitational-Wave Observatory (LIGO), a pair of detectors in Louisiana and Washington state, and Virgo, a similar detector in Italy.

It's the 2.6-solar-mass object that raises eyebrows because it falls squarely in the mass gap, says Vicky Kalogera, an astrophysicist and LIGO team member from Northwestern University. "Now, for the first time, we have seen such an object," she says. By sensing only the gravitational waves from the collision, LIGO and Virgo cannot tell for sure what the object is, she says. But nuclear physics suggests a neutron star heavier than about 2.2 solar masses cannot support its own weight, so the object is "almost certainly" a black hole, Miller says. The study has been published in The Astrophysical Journal Letters.

Facebook is "aiding and abetting the spread of climate misinformation," said Robert Brulle, an environmental sociologist at Drexel University. "They have become the vehicle for climate misinformation, and thus should be held partially responsible for a lack of action on climate change." From a report: Brulle was reacting to Facebook's recent decision, made at the request of climate science deniers, to create a giant loophole in its fact-checking program. Last year, Facebook partnered with an organization, Science Feedback, that would bring in teams of Ph.D. climate scientists to evaluate the accuracy of viral content. It was an important expansion of the company's third-party fact-checking program. But now Facebook has reportedly decided to allow its staffers to overrule the climate scientists and make any climate disinformation ineligible for fact-checking by deeming it "opinion."

The organization that requested the change, the CO2 Coalition, is celebrating, E&E news reported on Monday. The group, which has close ties to the fossil fuel industry, says its views on climate change are increasingly ignored by the mainstream media. Now it plans to use Facebook to aggressively push climate misinformation on the public -- without having to worry about fact checks from climate scientists. A column published in the Washington Examiner in August 2019 claimed that "climate models" were a "failure" that predicted exponentially more warming of the earth than has occurred. The piece, co-authored by notorious climate science denier Pat Michaels, was quickly shared more than 2,000 times on Facebook. There was just one issue: It wasn't true. This is exactly the kind of mess that Facebook's network of independent fact-checkers is supposed to solve.

As part of NASA's next mission to Mars, leaving Earth this summer, the space agency will attempt to do something that has never been done before: fly a helicopter through the rarefied atmosphere of Mars. The New York Times reports: If it works, the small helicopter, named Ingenuity, will open a new way for future robotic explorers to get a bird's-eye view of Mars and other worlds in the solar system. "This is very analogous to the Wright brothers moment, but on another planet," said MiMi Aung, the project manager of the Mars helicopter at NASA's Jet Propulsion Laboratory over the past six years.

Flying on Mars is not a trivial endeavor. There is not much air there to push against to generate lift. At the surface of Mars, the atmosphere is just 1/100th as dense as Earth's. The lesser gravity -- one-third of what you feel here -- helps with getting airborne. But taking off from the surface of Mars is the equivalent of flying at an altitude of 100,000 feet on Earth. No terrestrial helicopter has ever flown that high, and that's more than twice the altitude that jetliners typically fly at. The copter will hitch a ride to the red planet with Perseverance, which is to be the fifth robotic rover NASA has sent there. The mission is scheduled to launch on July 20, one of three missions headed to Mars this year. At a news conference last week previewing the Perseverance mission, Jim Bridenstine, the NASA administrator, made a point to highlight Ingenuity. "I'll tell you, the thing that has me the most excited as an NASA administrator is getting ready to watch a helicopter fly on another world," he said.