A peculiar bacterial enzyme has allowed researchers to achieve what even the popular CRISPR-Cas9 genome-editing system couldn't manage: targeted changes to the genomes of mitochondria, cells' crucial energy-producing structures. From a report: The technique -- which builds on a super-precise version of gene editing called base editing -- could allow researchers to develop new ways to study, and perhaps even treat, diseases caused by mutations in the mitochondrial genome. Such disorders are most often passed down maternally, and impair the cell's ability to generate energy. Although there are only a small number of genes in the mitochondrial genome compared with the nuclear genome, these mutations can particularly harm the nervous system and muscles, including the heart, and can be fatal to people who inherit them.

But it has been difficult to study such disorders, because scientists lacked a way to make animal models with the same changes to the mitochondrial genome. The latest technique marks the first time that researchers have made such targeted changes, and could allow researchers to do this. "It's a very exciting development," says Carlos Moraes, a mitochondrial geneticist at the University of Miami in Florida. "The ability to modify mitochondrial DNA would allow us to ask questions that, before, we could not." The work was published on 8 July in Nature.

Can a daily drink or two lead to better health? For many years, the federal government's influential dietary guidelines implied as much, saying there was evidence that moderate drinking could lower the risk of heart disease and reduce mortality. But now a committee of scientists that is helping to update the latest edition of the Dietary Guidelines for Americans is taking a harder stance on alcohol. From a report: The committee said in a recent conference call that it plans to recommend that men and women who drink limit themselves to a single serving of wine, beer or liquor per day. Do not drink because you think it will make you healthier, the committee says: It won't. And it maintains that drinking less is generally better for health than drinking more. That message is a departure from previous guidelines, which since 1980 have defined "moderate" drinking as up to two drinks a day for men and one for women. Government agencies have also long defined a standard drink as 12 ounces of regular beer, five ounces of wine, or one and a half ounces of distilled spirits (40 percent alcohol), amounts often exceeded in Americans' typical "drink."

Between 1990 and 2010, many editions of the guidelines, which are updated every five years, discouraged heavy drinking and warned pregnant women and people with certain medical conditions not to drink. But they also noted that moderate drinking was linked to fewer heart attacks and lower mortality. The 2010 guidelines mentioned that moderate drinking may even "help to keep cognitive function intact with age." The new recommendation would be a victory for experts who have long questioned the health halo around moderate drinking. They say that studies showing it can protect health are deeply flawed, and that any potential cardiovascular benefits would be outweighed by the fact that alcohol is a leading preventable cause of cancer. According to the National Cancer Institute, even one drink a day increases the risk of breast, esophageal and oral cancer. The new advice is not yet final. The advisory panel is expected to include it in a report that it will release publicly in mid-July and submit to the Department of Agriculture and the Department of Health and Human Services. Those two agencies are scheduled to publish the official dietary guidelines later this year.

Special cells in giant clams shift the wavelength of light to protect them from UV radiation and increase the photosynthetic activity of their symbionts, shows research from King Abdullah University of Science and Technology -- originally intended as a photonics investigation. Phys.Org reports: Like corals, giant clams are important players in reef ecosystems and live in symbiosis with photosynthetic Symbiodiniaceae algae. The clams also have special cells, known as iridocytes, that can manipulate light via layers of nanoreflectors within each cell. Earlier work has shown that these iridocytes scatter and reflect light to increase the photosynthetic efficiency of the Symbiodiniaceae algae. Now, a team of researchers at the Red Sea Research Center and the Photonics Laboratory have discovered another way that iridocytes help the symbiont to photosynthesize. The researchers studied the morphology and optical characteristics of iridocytes in the giant clam Tridacna maxima and found that they absorb UV radiation and re-emit it as longer wavelength, photosynthetically useful light.

Ram Chandra Subedi, one of the study's authors, explains that the iridocytes contain alternating layers of high-refractive index guanine crystal and lower refractive index cytoplasm. Compressing and relaxing these layers enables the cell to tune its effect on light. As a result, "the guanine palettes not only reflect harmful UV radiation but also absorb it, and emit light at higher wavelengths which are safe and useful for photosynthesis," he explains. This increases the amount of photosynthetically active radiation available to the algal symbiont and also helps protect both the clams and algae from UV radiation. This photoprotective effect enables giant calms to live in very shallow tropical waters where there is enough light for photosynthesis, but also potentially harmful UV radiation levels. The report adds that this research may help explain the mantle colors of giant clams. "The idea is that the vibrant colors of giant clams are not due to optical differences in the tissue, but rather differences in the distribution or abundance of symbionts relative to iridocytes in each individual," reports Phys.Org.

The research has been published in the journal Frontiers in Marine Science.

Trying to get an up close and personal look at the solar system's gas giants is a tricky and dangerous journey. From a report: Jupiter, like the other gas giants, doesn't have a rocky surface, but that doesn't mean it's just a massive cloud floating through the vacuum of space. It's made up of mostly helium and hydrogen, and as you move from the outer layers of the atmosphere toward the deeper parts, that gas grows denser and the pressures become more extreme. Temperatures quickly rise. In 1995, NASA's Galileo mission sent a probe into Jupiter's atmosphere; it broke up at about 75 miles in depth. Pressures here are over 100 times more intense than anything on Earth. At the innermost layers of Jupiter that are 13,000 miles deep, the pressure is 2 million times stronger than what's experienced at sea level on Earth, and temperatures are hotter than the sun's surface.

So clearly, no human is going to be able to venture too far down into Jupiter's depths. But would it be safe to simply orbit the planet? Perhaps we could establish an orbital space station, right? Well, there's another big problem when it comes to Jupiter: radiation. The biggest planet in the solar system also boasts its most powerful magnetosphere. These magnetic fields charge up particles in the vicinity, accelerating them to extreme speeds that can fry a spacecraft's electronics in moments. Spaceflight engineers have to figure out an orbit and spacecraft design that will reduce the exposure to this radiation. NASA figured this out with the triple-arrayed, perpetually spinning Juno spacecraft, but it doesn't look as if this would be a feasible design for a human spacecraft. Instead, for a crewed spacecraft to safely orbit or fly past Jupiter, it would have to keep a pretty significant distance away from the planet.

An anonymous reader quotes a report from Phys.Org: A ringing bell vibrates simultaneously at a low-pitched fundamental tone and at many higher-pitched overtones, producing a pleasant musical sound. A recent study, just published in the Journal of the Atmospheric Sciences by scientists at Kyoto University and the University of Hawai'i at Mnoa, shows that the Earth's entire atmosphere vibrates in an analogous manner, in a striking confirmation of theories developed by physicists over the last two centuries. In the case of the atmosphere, the "music" comes not as a sound we could hear, but in the form of large-scale waves of atmospheric pressure spanning the globe and traveling around the equator, some moving east-to-west and others west-to-east. Each of these waves is a resonant vibration of the global atmosphere, analogous to one of the resonant pitches of a bell.

Now in a new study by Takatoshi Sakazaki, an assistant professor at the Kyoto University Graduate School of Science, and Kevin Hamilton, an Emeritus Professor in the Department of Atmospheric Sciences and the International Pacific Research Center at the University of Hawaii at Mnoa, the authors present a detailed analysis of observed atmospheric pressure over the globe every hour for 38 years. The results clearly revealed the presence of dozens of the predicted wave modes. The study focused particularly on waves with periods between 2 hours and 33 hours which travel horizontally through the atmosphere, moving around the globe at great speeds (exceeding 700 miles per hour). This sets up a characteristic "chequerboard" pattern of high and low pressure associated with these waves as they propagate. "For these rapidly moving wave modes, our observed frequencies and global patterns match those theoretically predicted very well," stated lead author Sakazaki. "It is exciting to see the vision of Laplace and other pioneering physicists so completely validated after two centuries."

Spreading rock dust on farmland could suck billions of tons of carbon dioxide from the air every year, according to the first detailed global analysis of the technique. The Guardian reports: The chemical reactions that degrade the rock particles lock the greenhouse gas into carbonates within months, and some scientists say this approach may be the best near-term way of removing CO2 from the atmosphere. The rock dust approach, called enhanced rock weathering (ERW), has several advantages, the researchers say. First, many farmers already add limestone dust to soils to reduce acidification, and adding other rock dust improves fertility and crop yields, meaning application could be routine and desirable.

Basalt is the best rock for capturing CO2, and many mines already produce dust as a byproduct, so stockpiles already exist. The researchers also found that the world's biggest polluters, China, the U.S. and India, have the greatest potential for ERW, as they have large areas of cropland and relatively warm weather, which speeds up the chemical reactions. The analysis, published in the journal Nature, estimates that treating about half of farmland could capture 2 billion tons of CO2 each year, equivalent to the combined emissions of Germany and Japan. The cost depends on local labor rates and varies from $80 per ton in India to $160 in the U.S., and is in line with the $100-150 carbon price forecast by the World Bank for 2050, the date by which emissions must reach net zero to avoid catastrophic climate breakdown.

An anonymous reader quotes a report from Phys.Org: Tiny, 3-D printed cubes of plastic, with intricate fractal voids built into them, have proven to be effective at dissipating shockwaves, potentially leading to new types of lightweight armor and structural materials effective against explosions and impacts. "The goal of the work is to manipulate the wave interactions resulting from a shockwave," said Dana Dattelbaum, a scientist at Los Alamos National Laboratory and lead author on a paper to appear in the journal AIP Advances. "The guiding principles for how to do so have not been well defined, certainly less so compared to mechanical deformation of additively manufactured materials. We're defining those principles, due to advanced, mesoscale manufacturing and design."

The researchers tested their fractal structures by firing an impactor into them at approximately 670 miles per hour. The structured cubes dissipated the shocks five times better than solid cubes of the same material. Although effective, it's not clear that the fractal structure is the best shock-dissipating design. The researchers are investigating other void- or interface-based patterns in search of ideal structures to dissipate shocks. New optimization algorithms will guide their work to structures outside of those that consist of regular, repeating structures. Potential applications might include structural supports and protective layers for vehicles, helmets, or other human-wearable protection. The research will be published in the July 2020 issue of AIP Advances.

Doctors may be missing signs of serious and potentially fatal brain disorders triggered by coronavirus, as they emerge in mildly affected or recovering patients, scientists have warned. From a report: Neurologists are on Wednesday publishing details of more than 40 UK Covid-19 patients whose complications ranged from brain inflammation and delirium to nerve damage and stroke. In some cases, the neurological problem was the patient's first and main symptom. The cases, published in the journal Brain, revealed a rise in a life-threatening condition called acute disseminated encephalomyelitis (Adem), as the first wave of infections swept through Britain. At UCL's Institute of Neurology, Adem cases rose from one a month before the pandemic to two or three per week in April and May. One woman, who was 59, died of the complication. A dozen patients had inflammation of the central nervous system, 10 had brain disease with delirium or psychosis, eight had strokes and a further eight had peripheral nerve problems, mostly diagnosed as Guillain-Barre syndrome, an immune reaction that attacks the nerves and causes paralysis. It is fatal in 5% of cases.

After hundreds of experts urged the World Health Organization to review mounting scientific research, the agency acknowledged on Tuesday that airborne transmission of the coronavirus may be a threat in indoor spaces. The New York Times reports: W.H.O. expert committees are going over evidence on transmission of the virus and plan to release updated recommendations in a few days, agency scientists said in a news briefing. The possibility of airborne transmission, especially in "crowded, closed, poorly ventilated settings, cannot be ruled out," said Dr. Benedetta Allegranzi, who leads the W.H.O.'s committee on infection prevention and control. She said the agency recommends "appropriate and optimal ventilation" of indoor environments, as well as physical distancing.

Agency staff fielded several questions from reporters about transmission of the virus by air, prompted by an open letter from 239 experts calling on the agency to review its guidance. Many of the letter's signatories have collaborated with the W.H.O. and served on its committees. [...] W.H.O. scientists said that for the past few months, the infection prevention committee has been weighing the evidence on all the ways in which the coronavirus spreads, including by tiny droplets or aerosols. "We acknowledge that there is emerging evidence in this field, as in all other fields," Dr. Allegranzi said. "And therefore, we believe that we have to be open to this evidence and understand its implications regarding the modes of transmission and also regarding the precautions that need to be taken." It will also be important to understand the importance of transmission by aerosols compared with larger droplets, and the dose of the virus needed for infection from aerosols, she said. "These are fields that are really growing and for which there is evidence emerging, but it is not definitive," she said. "However, the evidence needs to be gathered and interpreted, and we continue to support this."

The American Mathematical Society has announced the passing of Ronald Graham, "one of the principal architects of the rapid development worldwide of discrete mathematics in recent years." He died July 6th at the age of 84. From the report: Graham published more than 350 papers and books with many collaborators, including more than 90 with his wife, Fan Chung, and more than 30 with Paul Erdos. In addition to writing articles with Paul Erdos, Graham had a room in his house reserved for Erdos's frequent visits, he administered the cash prizes that Erdos created for various problems, and he created the Erdos number, which is the collaboration distance between a mathematician and Erdo's. He also created Graham's number in a 1971 paper on Ramsey theory written with Bruce Rothschild, which was for a time the largest number used in a proof.

Graham received his PhD from the University of California, Berkeley in 1962 under the direction of D.H. Lehmer. He worked at Bell Laboratories until 1999, starting as director of information sciences and ending his tenure there as chief scientist. Graham then joined the faculty at the University of California, San Diego and later became chief scientist at the California Institute for Telecommunications and Information Technology, a joint operation between the university and the University of California, Irvine. [...] Graham was an AMS member since 1961. For more information, see his "special page," these video interviews by the Simons Foundation, an audio interview about the mathematics of juggling, and his page at the MacTutor website. Graham's most recent appearance on Slashdot was in 2016, when a trio of researchers used a supercomputer to generate the largest math proof ever at 200 terabytes in size. The math problem was named the boolean Pythagorean Triples problem and was first proposed back in the 1980's by mathematician Ronald Graham.

Some days seem to pass very slowly while some weeks, and even months, fly by. A set of simple perception tests illustrate some factors that can distort our sense of time.

Brazilian President Jair Bolsonaro has tested positive for Covid-19, following months of downplaying the virus. From a report: Bolsonaro himself announced the result, speaking on Brazilian TV channels Tuesday. "Everyone knew that it would reach a considerable part of the population sooner or later. It was positive for me," he said, referring to the Covid-19 test he took Monday. "On Sunday, I wasn't feeling very well. On Monday, it got worse when I started feeling tired and some muscle pain. I also had a 38-degree [Celsius] fever. Given those symptoms, the presidential doctor said there was suspicion of Covid-19," Bolsonaro said, adding that he then went to hospital where scans of his lungs "came back clean."

Earlier on Tuesday, Bolsonaro told CNN affiliate CNN Brasil that he had been treated with hydroxychloroquine and azithromycin as he awaited the result of his fourth Covid-19 test in four months. Hydroxychloroquine, though enthusiastically boosted by both Bolsonaro and US President Donald Trump, has not been proven as an effective treatment for Covid-19. Bolsonaro nevertheless credited the controversial antimalarial drug for his well-being on Tuesday. "I am feeling very well. I believe that the way they administered the hydroxychloroquine on, the effect was immediate," he said.

schwit1 shares a report from UPI: The most popular theory of the moon's origins contends the satellite was formed when a Mars-sized object collided with Earth, vaporizing large portions of Earth's upper crust. While Earth's upper crust is poor in metals, new research -- published Wednesday in the journal Earth and Planetary Science Letters -- suggests the moon's subsurface is surprisingly metal-rich, undermining the satellite's proposed origin story. Authors of the new study suggest planetary scientists consider alternative theories for the moon's formation.

It's possible the collision that forged the moon was more violent than scientists thought, gouging out even deeper portions of Earth's crust and mantle. It's also possible the moon experienced an unusual cool-down process, post-collision -- a process that left the moon with large concentrations of metal.

China has confirmed one case of bubonic plague in northern province Inner Mongolia, according to a statement on the local health authority's website. From a report: The patient is now under treatment at a hospital and is in a stable condition, the Bayannur health commission said in a late Sunday night statement. It also issued a level-three alert, warning of the risks of human-to-human infection and urging citizens to report dead animals, suspected plague cases and patients running a fever for unidentified reasons. Bubonic plague, also called the 'Black Death,' killed 50 million people in a 14th century outbreak in Europe and about 12 million globally in the 19th century. It's now the most common type of plague and can be treated with antibiotics.

Inner Mongolia reported four cases in November while Madagascar sees some cases nearly every year between the months of September and April. Mongolia also confirmed two cases of bubonic plague earlier this month, triggering a quarantine in the province that borders China and Russia. While the ailment is treatable, unlike the novel pathogen which has caused the ongoing pandemic, Chinese health authorities are wary of any infectious disease spreading after a hard-fought containment of the coronavirus outbreak.

A stretch of DNA linked to Covid-19 was passed down from Neanderthals 60,000 years ago, according to a new study. From a report: Scientists don't yet know why this particular segment increases the risk of severe illness from the coronavirus. But the new findings, which were posted online on Friday and have not yet been published in a scientific journal, show how some clues to modern health stem from ancient history. "This interbreeding effect that happened 60,000 years ago is still having an impact today," said Joshua Akey, a geneticist at Princeton University who was not involved in the new study. This piece of the genome, which spans six genes on Chromosome 3, has had a puzzling journey through human history, the study found. The variant is now common in Bangladesh, where 63 percent of people carry at least one copy. Across all of South Asia, almost one-third of people have inherited the segment.

Elsewhere, however, the segment is far less common. Only 8 percent of Europeans carry it, and just 4 percent have it in East Asia. It is almost completely absent in Africa. It's not clear what evolutionary pattern produced this distribution over the past 60,000 years. "That's the $10,000 question," said Hugo Zeberg, a geneticist at the Karolinska Institute in Sweden who was one of the authors of the new study. One possibility is that the Neanderthal version is harmful and has been getting rarer over all. It's also possible that the segment improved people's health in South Asia, perhaps providing a strong immune response to viruses in the region.

Tesla is building mobile molecule printers to produce a potential COVID-19 vaccine being developed in Germany by CureVac, reports Reuters: CureVac, an unlisted German company, has said it is developing portable, automated mRNA production units that it calls printers and which Musk described as "RNA microfactories". They are being designed to be shipped to remote locations, where they can churn out its vaccine candidate and other mRNA-based therapies depending on the recipe fed into the machine. But for the immediate pandemic use — should its vaccine candidate win market approval — it has production sites with regulatory approval in Germany with a capacity to produce hundreds of millions of doses. The company, based in Tuebingen and backed by the Bill & Melinda Gates Foundation, is a pioneer of the so-called messenger RNA approach, which is also pursued by BioNTech and its partner Pfizer as well as Moderna....

The "microfactories" would be built at Tesla Grohmann Automation in Germany, Musk said in a Twitter thread late on Wednesday night.

"Six months into a pandemic that has killed over half a million people, more than 200 scientists from around the world are challenging the official view of how the coronavirus spreads," reports the Los Angeles Times: The World Health Organization and the U.S. Centers for Disease Control and Prevention maintain that you have to worry about only two types of transmission: inhaling respiratory droplets from an infected person in your immediate vicinity or — less common — touching a contaminated surface and then your eyes, nose or mouth.

But other experts contend that the guidance ignores growing evidence that a third pathway also plays a significant role in contagion.

They say multiple studies demonstrate that particles known as aerosols — microscopic versions of standard respiratory droplets — can hang in the air for long periods and float dozens of feet, making poorly ventilated rooms, buses and other confined spaces dangerous, even when people stay six feet from one another. "We are 100% sure about this," said Lidia Morawska, a professor of atmospheric sciences and environmental engineering at Queensland University of Technology in Brisbane, Australia. She makes the case in an open letter to the WHO accusing the United Nations agency of failing to issue appropriate warnings about the risk. A total of 239 researchers from 32 countries signed the letter, which is set to be published next week in a scientific journal.

In interviews, experts said that aerosol transmission appears to be the only way to explain several "super-spreading" events, including the infection of diners at a restaurant in China who sat at separate tables and of choir members in Washington state who took precautions during a rehearsal... The proponents of aerosol transmission said masks worn correctly would help prevent the escape of exhaled aerosols as well as inhalation of the microscopic particles. But they said the spread could also be reduced by improving ventilation and zapping indoor air with ultraviolet light in ceiling units.
The Times also got a response from Dr. Benedetta Allegranzi, a top WHO expert on infection prevention and control, who argued the group only presented theories based on experiments rather than actual evidence from the field.

Allegranzi also added that in weekly teleconferences, a large majority of a group of more than 30 international experts advising the WHO had "not judged the existing evidence sufficiently convincing to consider airborne transmission as having an important role in COVID-19 spread."

"The World Health Organization announced Saturday that it discontinued its trial on hydroxychloroquine's effect on COVID-19 patients in hospitals," reports UPI: WHO said in a statement that it accepted a recommendation from the Solidarity Trial's International Steering Committee that it stop the testing of the drug. The decision to cease the trial came after interim trial results showed that the anti-malaria drug had little or no reduction in mortality of patients hospitalized for the novel coronavirus...

The National Institute of Health similarly halted a hydroxychloroquine trial last month after a study showed no harm or benefit from the anti-malaria drug's use in hospitalized COVID-19 patients. Last month, British researchers similarly found no benefit of hydroxychloroquine.

"A surprising new study found the controversial antimalarial drug hydroxychloroquine helped patients better survive in the hospital," reports CNN. "But the findings, like the federal government's use of the drug itself, were disputed." A team at Henry Ford Health System in southeast Michigan said Thursday their study of 2,541 hospitalized patients found that those given hydroxychloroquine were much less likely to die. Dr. Marcus Zervos, division head of infectious disease for Henry Ford Health System, said 26% of those not given hydroxychloroquine died, compared to 13% of those who got the drug. The team looked back at everyone treated in the hospital system since the first patient in March. "Overall crude mortality rates were 18.1% in the entire cohort, 13.5% in the hydroxychloroquine alone group, 20.1% among those receiving hydroxychloroquine plus azithromycin, 22.4% among the azithromycin alone group, and 26.4% for neither drug," the team wrote in a report published in the International Journal of Infectious Diseases.

It's a surprising finding because several other studies have found no benefit from hydroxychloroquine, a drug originally developed to treat and prevent malaria...

"Our results do differ from some other studies," Zervos told a news conference. "What we think was important in ours ... is that patients were treated early. For hydroxychloroquine to have a benefit, it needs to begin before the patients begin to suffer some of the severe immune reactions that patients can have with Covid," he added. The Henry Ford team also monitored patients carefully for heart problems, he said...

Researchers not involved with the study were critical. They noted that the Henry Ford team did not randomly treat patients but selected them for various treatments based on certain criteria. "As the Henry Ford Health System became more experienced in treating patients with COVID-19, survival may have improved, regardless of the use of specific therapies," Dr. Todd Lee of the Royal Victoria Hospital in Montreal, Canada, and colleagues wrote in a commentary in the same journal. "Finally, concomitant steroid use in patients receiving hydroxychloroquine was more than double the non-treated group. This is relevant considering the recent RECOVERY trial that showed a mortality benefit with dexamethasone." The steroid dexamethasone can reduce inflammation in seriously ill patients...

Eli Rosenberg [lead author of a New York study of hydroxychloroquine], also pointed out that the Detroit paper excluded 267 patients — nearly 10% of the study population — who had not yet been discharged from the hospital. He said this might have skewed the results to make hydroxychloroquine look better than it really was.

"There's a little bit of loosey-goosiness here in all this," he told CNN.

An anonymous reader quotes Ars Technica: On Sunday morning, local time in New Zealand, Rocket Lab launched its 13th mission. The booster's first stage performed normally, but just as the second stage neared an altitude of 200km, something went wrong and the vehicle was lost...

"We lost the flight late into the mission," said Peter Beck, the company's founder and chief executive, on Twitter. "I am incredibly sorry that we failed to deliver our customers satellites today. Rest assured we will find the issue, correct it and be back on the pad soon."

The mission, dubbed "Pics Or It Didn't Happen," carried 5 SuperDove satellites for the imaging company Planet, as well as commercial payloads both for Canon Electronics and In-Space Missions. "The In-Space team is absolutely gutted by this news," the company said after the loss. Its Faraday-1 spacecraft hosted multiple experiments within a 6U CubeSat. "Two years of hard work from an incredibly committed group of brilliant engineers up in smoke. It really was a very cool little spacecraft."
The article notes that since January of 2018, "the company had rattled off a string of 11 successful missions and emerged as a major player in the small satellite launch industry."

In a video statement on Twitter, company founder Peter Beck said solemnly that "Today's issue is a reminder that space flight can be very unforgiving."