Nasa is delaying a spacewalk at the International Space Station because of a medical issue involving one of its astronauts. From a report: Officials announced the postponement on Monday, less than 24 hours before Mark Vande Hei was supposed to float outside. Vande Hei was dealing with "a minor medical issue," officials said. It was not an emergency, they noted, but did not provide any further details. Vande Hei, 54, a retired army colonel, has been at the space station since April and is expected to remain there until next spring for a one-year mission. This is his second station stay.

An anonymous reader quotes a report from New Scientist, written by Matthew Sparkes: Ant colonies can descend several meters underground, house millions of insects and last for decades, despite being made without the benefit of machinery and reinforcing material. The secrets of these impressive architectural structures are being revealed by three-dimensional X-ray imaging and computer simulations, and could be used to develop robotic mining machines. Jose Andrade at the California Institute of Technology and his colleagues set up miniature ant colonies in a container holding 500 milliliters of soil and 15 western harvester ants (Pogonomyrmex occidentalis). The position of every ant and every grain of soil was then captured by high-resolution X-ray scans every 10 minutes for 20 hours. The X-ray results gave researchers exact details about the shape of each tunnel and which grains were being removed to create it. The team then created a computer model using those scans to understand the forces acting upon the tunnels. The size, shape and orientation of every grain was recreated in the model and the direction and size of force on each grain could be calculated, including gravity, friction and cohesion caused by humidity. The model was accurate to the 0.07 millimeter resolution of the scanner.

The results suggest that forces within the soil tend to wrap around the tunnel axis as ants excavate, forming what the team call "arches" in the soil that have a greater diameter than the tunnel itself. This reduces the load acting on the soil particles within the arches, where the ants are constructing their tunnel. As a result, the ants can easily remove these particles to extend the tunnel without causing cave-ins. The arches also make the tunnel stronger and more durable. "We had naively thought that ants perhaps were playing Jenga, that they were tapping, maybe they were wiggling grains, maybe they were even grabbing the grains of least resistance," says Andrade. He says it is now clear that the ants appear to know nothing about forces and show no signs of decision-making, but instead follow a very simple behavioral algorithm that has evolved over time.

The ants tend to dig relatively straight tunnels that descend at the angle of repose -- the slope at which a granular material naturally forms mounds -- which was around 40 degrees in this case. They also pick exactly the right grains to remove to create a protective arch above. "In a remarkable way -- in a rather, you know, serendipitous way -- they've stumbled upon a technique for digging that is in line with the laws of physics, but incredibly efficient," says Andrade. The team believes that if the behavioral algorithm can be further analyzed and ultimately replicated, then it may find application in automated mining robots, either here on Earth or on other planetary bodies where the already risky business of mining would be even more dangerous for humans. The findings have been published in the journal Proceedings of the National Academy of Sciences.

Michelle Starr writes via ScienceAlert: Gravity is the weird, mysterious glue that binds the Universe together, but that's not the limit of its charms. We can also leverage the way it warps space-time to see distant objects that would be otherwise much more difficult to make out. This is called gravitational lensing, an effect predicted by Einstein, and it's beautifully illustrated in a new release from the Hubble Space Telescope. In the center in the image is a shiny, near-perfect ring with what appear to be four bright spots threaded along it, looping around two more points with a golden glow. This is called an Einstein ring, and those bright dots are not six galaxies, but three: the two in the middle of the ring, and one quasar behind it, its light distorted and magnified as it passes through the gravitational field of the two foreground galaxies. Because the mass of the two foreground galaxies is so high, this causes a gravitational curvature of space-time around the pair. Any light that then travels through this space-time follows this curvature and enters our telescopes smeared and distorted -- but also magnified. [...]

This, as it turns out, is a really useful tool for probing both the far and near reaches of the Universe. Anything with enough mass can act as a gravitational lens. That can mean one or two galaxies, as we see here, or even huge galaxy clusters, which produce a wonderful mess of smears of light from the many objects behind them. Astronomers peering into deep space can reconstruct these smears and replicated images to see in much finer detail the distant galaxies thus lensed. But that's not all gravitational lensing can do. The strength of a lens depends on the curvature of the gravitational field, which is directly related to the mass it's curving around. So gravitational lenses can allow us to weigh galaxies and galaxy clusters, which in turn can then help us find and map dark matter -- the mysterious, invisible source of mass that generates additional gravity that can't be explained by the stuff in the Universe we can actually detect. [...] You can download a wallpaper-sized version of the [...] image on ESA's website.

An anonymous reader quotes a report from Phys.Org: Researchers have developed a mathematical model that can predict the optimum exercise regime for building muscle. The researchers, from the University of Cambridge, used methods of theoretical biophysics to construct the model, which can tell how much a specific amount of exertion will cause a muscle to grow and how long it will take. The model could form the basis of a software product, where users could optimize their exercise regimes by entering a few details of their individual physiology. The results, reported in the Biophysical Journal, suggest that there is an optimal weight at which to do resistance training for each person and each muscle growth target. Muscles can only be near their maximal load for a very short time, and it is the load integrated over time which activates the cell signaling pathway that leads to synthesis of new muscle proteins. But below a certain value, the load is insufficient to cause much signaling, and exercise time would have to increase exponentially to compensate. The value of this critical load is likely to depend on the particular physiology of the individual.

In 2018, the Cambridge researchers started a project on how the proteins in muscle filaments change under force. They found that main muscle constituents, actin and myosin, lack binding sites for signaling molecules, so it had to be the third-most abundant muscle component -- titin -- that was responsible for signaling the changes in applied force. Whenever part of a molecule is under tension for a sufficiently long time, it toggles into a different state, exposing a previously hidden region. If this region can then bind to a small molecule involved in cell signaling, it activates that molecule, generating a chemical signal chain. Titin is a giant protein, a large part of which is extended when a muscle is stretched, but a small part of the molecule is also under tension during muscle contraction. This part of titin contains the so-called titin kinase domain, which is the one that generates the chemical signal that affects muscle growth. The molecule will be more likely to open if it is under more force, or when kept under the same force for longer. Both conditions will increase the number of activated signaling molecules. These molecules then induce the synthesis of more messenger RNA, leading to production of new muscle proteins, and the cross-section of the muscle cell increases.

This realization led to the current work. [The researchers] set out to constrict a mathematical model that could give quantitative predictions on muscle growth. They started with a simple model that kept track of titin molecules opening under force and starting the signaling cascade. They used microscopy data to determine the force-dependent probability that a titin kinase unit would open or close under force and activate a signaling molecule. They then made the model more complex by including additional information, such as metabolic energy exchange, as well as repetition length and recovery. The model was validated using past long-term studies on muscle hypertrophy. "Our model offers a physiological basis for the idea that muscle growth mainly occurs at 70% of the maximum load, which is the idea behind resistance training," said [one of the paper's authors]. "Below that, the opening rate of titin kinase drops precipitously and precludes mechanosensitive signaling from taking place. Above that, rapid exhaustion prevents a good outcome, which our model has quantitatively predicted." [...] The model also addresses the problem of muscle atrophy, which occurs during long periods of bed rest or for astronauts in microgravity, showing both how long can a muscle afford to remain inactive before starting to deteriorate, and what the optimal recovery regime could be.

An anonymous reader quotes a report from The Mercury News, written by Harriet Blair Rowan: In a significant twist that could reshape our understanding of the early days of the coronavirus pandemic, death records now indicate the first COVID-related deaths in California and across the country occurred in January 2020, weeks earlier than originally thought and before officials knew the virus was circulating here. A half dozen death certificates from that month in six different states -- California, Alabama, Georgia, Kansas, Oklahoma and Wisconsin -- have been quietly amended to list COVID-19 as a contributing factor, suggesting the virus's deadly path quickly reached far beyond coastal regions that were the country's early known hotspots. Up until now, the Feb. 6, 2020, death of San Jose's Patricia Dowd had been considered the country's first coronavirus fatality, although where and how she was infected remains unknown.

Even less is known about what are now believed to be the country's earliest victims of the pandemic. The Bay Area News Group discovered evidence of them in provisional coronavirus death counts of the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS) -- widely considered the definitive source for death data in the United States -- and confirmed the information through interviews with state and federal public health officials. But amid privacy concerns and fierce debate over pandemic policies, the names, precise locations and circumstances behind these deaths have not been publicly revealed. That is frustrating to some experts.

The existence of January 2020 deaths would dramatically revise the timeline of COVID's arrival in the United States. China first announced a mysterious viral pneumonia in late December 2019, and reported the first death from the illness on Jan. 9, 2020. The U.S. originally recorded its first case in mid-January when a traveler tested positive after returning from Wuhan, China. The first deaths reported in the United States, in late February, were also tied to travel. In its current death count, which reflects the six newly-discovered fatalities, the NCHS now lists the country's first COVID death during the week of Jan. 5-11 -- the first full week of 2020. The agency is in the final stages of preparing its 2020 annual mortality report, a review and analysis of all deaths in the United States last year.

The Covid-19 vaccine made by Pfizer and BioNTech was granted a full approval by U.S. regulators, a move that is expected to help bolster the immunization drive amid a surge in infections caused by the delta variant. From a report: The Food and Drug Administration said in a statement on Monday that it had cleared the vaccine for the prevention of Covid-19 in individuals 16 years of age and older. It will be marketed under the name Comirnaty. The vaccine continues to be available to people age 12 to 15 under an emergency-use authorization, the agency said. The approval is expected to boost confidence in the shot and is likely to open the door to more vaccine mandates among employers and businesses. It is also likely to solidify its future as a blockbuster for its makers.

"According to addiction expert Dr Anna Lembke, our smartphones are making us dopamine junkies," reports the Guardian, "with each swipe, like and tweet feeding our habit..." As the chief of Stanford University's dual diagnosis addiction clinic (which caters to people with more than one disorder), Lembke has spent the past 25-plus years treating patients addicted to everything from heroin, gambling and sex to video games, Botox and ice baths... Her new book, Dopamine Nation, emphasises that we are now all addicts to a degree. She calls the smartphone the "modern-day hypodermic needle": we turn to it for quick hits, seeking attention, validation and distraction with each swipe, like and tweet. Since the turn of the millennium, behavioural (as opposed to substance) addictions have soared. Every spare second is an opportunity to be stimulated... "We're seeing a huge explosion in the numbers of people struggling with minor addictions," says Lembke.

That has consequences. Although we have endless founts of fun at our fingertips, "the data shows we're less and less happy," she says. Global depression rates have been climbing significantly in the past 30 years and, according to a World Happiness Report, people in high-income countries have become more unhappy over the past decade or so. We've forgotten how to be alone with our thoughts. We're forever "interrupting ourselves", as Lembke puts it, for a quick digital hit, meaning we rarely concentrate on taxing tasks for long or get into a creative flow. For many, the pandemic has exacerbated dependence on social media and other digital vices, as well as alcohol and drugs.

Addiction is a spectrum disorder: it's not as simple as being an addict or not being an addict. It's deemed worthy of clinical care when it "significantly interferes" with someone's life and ability to function, but when it comes to minor digital attachments, the effect is pernicious. "It gets into philosophical questions: how is the time I'm spending on my phone in subtle ways affecting my ability to be a good parent, spouse or friend?" says Lembke. "I do believe there is a cost — one that I don't think we fully recognise because it's hard to [see it] when you're in it...."

"It's very different from how life used to be, when we had to tolerate a lot more distress," says Lembke. "We're losing our capacity to delay gratification, solve problems and deal with frustration and pain in its many different forms."
The solution, according to the article, is dopamine fasts — "the longer, the better...to reset our brain's pathways and gain perspective on how our dependency affects us," eventually attaining the lost art of moderation.

In the U.S. healthcare system, "hospitals are charging patients wildly different amounts for the same basic services," reports the New York Times — citing an investigation into medical care costs at 60 major hospitals.

This year the U.S. government ordered hospitals to publish complete lists of the prices they negotiate with private insurers, "and it provides numerous examples of major health insurers — some of the world's largest companies, with billions in annual profits — negotiating surprisingly unfavorable rates for their customers." In fact America's government-run Medicare health insurance for senior citizens is negotiating much lower rates than the privately-insured patients are getting, the Times points out — sometimes paying just 10% of what the major health plans are paying.

"In many cases, insured patients are getting prices that are higher than they would if they pretended to have no coverage at all..." Until now, consumers had no way to know before they got the bill what prices they and their insurers would be paying. Some insurance companies have refused to provide the information when asked by patients and the employers that hired the companies to provide coverage. This secrecy has allowed hospitals to tell patients that they are getting "steep" discounts, while still charging them many times what a public program like Medicare is willing to pay. And it has left insurers with little incentive to negotiate well.

The peculiar economics of health insurance also help keep prices high. Customers judge insurance plans based on whether their preferred doctors and hospitals are covered, making it hard for an insurer to walk away from a bad deal. The insurer also may not have a strong motivation to, given that the more that is spent on care, the more an insurance company can earn. Federal regulations limit insurers' profits to a percentage of the amount they spend on care. And in some plans involving large employers, insurers are not even using their own money. The employers pay the medical bills, and give insurers a cut of the costs in exchange for administering the plan.

"In the long-running TV show Doctor Who, aliens known as time lords derived their power from the captured heart of a black hole, which provided energy for their planet and time travel technology," writes Science magazine.

"The idea has merit, according to a new study."

Slashdot reader sciencehabit quotes their report: Researchers have shown that highly advanced alien civilizations could theoretically build megastructures called Dyson spheres around black holes to harness their energy, which can be 100,000 times that of our Sun. The work could even give us a way to detect the existence of these extraterrestrial societies...

Black holes are typically thought of as consumers rather than producers of energy. Yet their huge gravitational fields can generate power through several theoretical processes. These include the radiation emitted from the accumulation of gas around the hole, the spinning "accretion" disk of matter slowly falling toward the event horizon, the relativistic jets of matter and energy that shoot out along the hole's axis of rotation, and Hawking radiation—a theoretical way that black holes can lose mass, releasing energy in the process.

From their calculations, researchers concluded that the accretion disk, surrounding gas, and jets of black holes can all serve as viable energy sources. In fact, the energy from the accretion disk alone of a stellar black hole of 20 solar masses could provide the same amount of power as Dyson spheres around 100,000 stars, the team will report next month in the Monthly Notices of the Royal Astronomical Society. Were a supermassive black hole harnessed, the energy it could provide might be 1 million times larger still.

If such technology is at work, there may be a way to spot it. According to the researchers, the waste heat signal from a so-called "hot" Dyson sphere—one somehow capable of surviving temperatures in excess of 3000 kelvin, above the melting point of known metals—around a stellar mass black hole in the Milky Way would be detectible at ultraviolet wavelengths. Such signals might be found in the data from various telescopes, including NASA's Hubble Space Telescope and Galaxy Evolution Explorer.

CNET reports: Using the same mRNA technology that broke the mold with effective COVID-19 vaccines, Moderna has developed two vaccines for HIV. The first phase of testing for both could begin as early as Thursday, according to a post on the National Institutes of Health website for clinical trials. Phase 1 of the vaccine trial will test the vaccines' safety, as well as measure immunity and antibody responses. If the vaccines prove to be safe, they'll need to go through additional testing for researchers to determine how effective they are...

There were 37.7 million people living with HIV globally in 2020, according to United Nations data.
"There's a pressing need for new ways to prevent infection from viruses like HIV and influenza that conventional vaccines have struggled to address and to treat rare genetic diseases and cancers that kill millions each year," writes a reporter at Axios. "Vaccines and therapies based on messenger RNA hold promise as a solution."

"A new island has been discovered near Iwo Jima," reports long-time Slashdot reader thephydes, "located around 1,200 kilometers [746 miles] south of Tokyo, after a submarine volcano began erupting late last week, the Japan Coast Guard said Monday." Japan Times reports: The new island is C-shaped with a diameter of approximately 1 kilometer [0.6 miles]. It was discovered after the volcano some 50 km south of Iwo Jima, part of the Ogasawara Islands in the Pacific Ocean, started erupting on Friday...

New islands have been confirmed in the area in 1904, 1914 and 1986, with all of them having submerged due to erosion by waves and currents. The one found in 1986 sank after about two months, according to the coast guard.

"COVID-19 origin theorists could be right about a Chinese government cover-up," reports The Week, "but they might have their sights set in the wrong direction, an American virologist suggested to Bloomberg." When an international group of experts organized by the World Health Organization traveled to Wuhan, China, earlier this year to research the origins of the coronavirus that sparked the ongoing COVID-19 pandemic, they visited the Baishazhou market, which is larger, but perhaps less well-known (internationally, at least) than the Huanan market, where many people initially believed the virus first jumped from wild animals to humans.

The research team was told only frozen foods, ingredients, and kitchenware were sold there. But a recently released study that had previously languished in publishing limbo showed, thanks to data meticulously collected over 30 months, that at least two vendors there regularly sold live wild animals, Bloomberg reports. Bloomberg also notes that one of the earliest recorded COVID-19 clusters in Wuhan [December 19th] involved a Huanan stall employee who traded goods back and forth between the two markets.

A link between them would be "very intriguing," Stephen Goldstein, an evolutionary virology research associate at the University of Utah, told Bloomberg...

[I]t seems likely to Goldstein that some authorities didn't want the presence of a thriving wildlife trade to become public knowledge. "It seems to me, at a minimum, that local or regional authorities kept that information quiet deliberately. It's incredible to me that people theorize about one type of cover-up," he said, likely referring to the hypothesis that the virus actually leaked from a nearby government-run lab, "but an obvious cover-up is staring them right in the face."
The paper contains "meticulously collected data and photographic evidence supporting scientists' initial hypothesis — that the outbreak stemmed from infected wild animals..." according to Bloomberg's article. (Alternate URL here.) According to the report, which was published in June in the online journal Scientific Reports, minks, civets, raccoon dogs, and other mammals known to harbor coronaviruses were sold in plain sight for years in shops across the city, including the now infamous Huanan wet market, to which many of the earliest Covid cases were traced... [Researcher Xiao Xiao's] animal logs included masked palm civets and raccoon dogs — both involved in the 2003 SARS outbreak — and other species susceptible to coronavirus infections, such as bamboo rats, minks, and hog badgers. Of the 38 species Xiao documented, 31 were protected.

Anyone caught violating China's wild animal conservation law faces fines and up to 15 years of imprisonment. But enforcement was lax, as evidenced by the fact that many of the Wuhan shops displayed their wares openly, "caged, stacked and in poor condition," Xiao observed in the report.

Xiao estimated that 47,381 wild animals were sold in Wuhan over the survey period.
Collaborating with four more scientists (including three from the University of Oxford), Xiao had submitted their manuscript to a journal for publication in February of 2020 — only to have it rejected. "Had the study been made public right away, the search for the origins of the virus might have taken a very different course..." Bloomberg writes: Disease detectives arriving from Beijing on the first day of 2020 ordered environmental samples to be collected from drains and other surfaces at the market. Some 585 specimens were tested, of which 33 turned out to be positive for SARS-CoV-2... All but two of the positive specimens came from a cavernous and poorly-ventilated section of the market's western wing, where many shops sold animals....

As other nations began blaming the Chinese Communist Party for the pandemic, the government grew defensive. It may have been embarrassed that its citizens were still eating wild animals bought in wet markets — a well-known path for zoonotic disease transmission that China tried unsuccessfully to outlaw almost 20 years ago...

Geng Shuang, a spokesman for China's Foreign Ministry, denied "wildlife wet markets" existed in the country...

According to a new paper published in the Proceedings of the Royal Society B, cuttlefish appear able to recall the time and place of their meals -- and their capability doesn't decrease as they get older. Ars Technica reports: This latest study focuses on whether cuttlefish have some form of episodic memory -- the ability to recall unique past events with context about what happened, where it happened, and when it happened. Human beings develop this capability around age 4, and our episodic memory declines as we advance into old age. That's in contrast to "semantic memory," our ability to recall general learned knowledge without the context of space and time. Semantic learning in humans has been shown to remain relatively intact with advancing age.

Cuttlefish lack a hippocampus, but they do have their own distinctive brain structure and organization, complete with a vertical lobe that shows similarities to the connectivity and function of the human hippocampus -- i.e., learning and memory. Past studies have shown that cuttlefish are sufficiently future-oriented that they can optimize foraging behavior and can remember details of what, where, and when from past forages -- hallmarks of episodic-like memory -- adjusting their strategy in response to changing prey conditions. But does that ability remain constant with age? [Co-author Alexandra Schnell of the University of Cambridge] et al. developed a series of semantic and episodic memory tests for cuttlefish to explore that question. The relatively short life span of cuttlefish (about two years) makes them an excellent candidate for this research.

For the experiments, Schnell and her colleagues used 24 common cuttlefish, half of which were young (between 10-12 months old) and half of which were old (22-24 months, apparently the equivalent of a human's 90 years). All had been reared from eggs at the Marine Biological Laboratory and were kept in individual tanks. The team first trained the cuttlefish to respond to visual cues (the waving of black and white flags) by marking specific locations in their respective tanks. As in Schnell's prior work on delayed gratification, the cuttlefish could choose their preferred prey -- in this case, either live grass shrimp or a piece of prawn meat of equal size. Over the next four weeks, the cuttlefish were taught that these two types of prey were available at specific locations (marked by the waving of the flags) after delays of either one hour (for the prawn meat) or three hours (for the preferred grass shrimp). The two feeding locations were unique for each day in order to ensure that the cuttlefish weren't merely learning a pattern. Surprisingly, Schnell et al. found that all the cuttlefish, regardless of age, were able to note which type of prey appeared first at each flagged location and were able to use that observation to figure out where to find their preferred prey at each subsequent feeding. Earlier this year, researchers found that cuttlefish could pass a cephalopod version of the famous Stanford marshmallow test: waiting a bit for their preferred prey rather than settling for a less desirable prey. "Cuttlefish also performed better in a subsequent learning test -- the first time such a link between self-control and intelligence has been found in a non-mammalian species," adds Ars.

China is preparing to launch an uncrewed cargo ship to its Tiangong "Heavenly palace" space station in preparation for the arrival of its second human crew this autumn. The Guardian reports: The Long March 7 rocket was delivered to the Wenchang space launch site in Hainan on 16 August, where it will undergo final assembly and testing. It will carry the Tianzhou 3 cargo ship into orbit sometime in mid to late September. Simultaneously, at the Jiuquan satellite launch centre in the Gobi desert, the Shenzhou 13 mission is being readied to transport the crew of three astronauts. A launch is planned for October and the astronauts are expected to stay in orbit until April 2022. The flight plan of a cargo ship followed by an astronaut vehicle matches the pattern of the first crew from earlier this year. Those three astronauts are still on Tiangong. They arrived in June and are expected to return to Earth in September.

An anonymous reader quotes a report from the BBC: India's drug regulator has approved the world's first DNA vaccine against Covid-19 for emergency use. The three-dose ZyCoV-D vaccine prevented symptomatic disease in 66% of those vaccinated, according to an interim study quoted by the vaccine maker Cadila Healthcare. The firm plans to make up to 120 million doses of India's second home-grown vaccine every year. Previous DNA vaccines have worked well in animals but not humans. Cadila Healthcare said it had conducted the largest clinical trial for the vaccine in India so far, involving 28,000 volunteers in more than 50 centers. This is also the first time, the firm claimed, a Covid-19 vaccine had been tested in young people in India -- 1,000 people belonging to the 12-18 age group. The jab was found to be "safe and very well tolerated" in this age group.

DNA and RNA are building blocks of life. They are molecules that carry that genetic information which are passed on from parents to children. Like other vaccines, a DNA vaccine, once administered, teaches the body's immune system to fight the real virus. ZyCoV-D uses plasmids or small rings of DNA, that contain genetic information, to deliver the jab between two layers of the skin. The plasmids carry information to the cells to make the "spike protein," which the virus uses to latch on and enter human cells.

ZyCov-D is also India's first needle-free Covid-19 jab. It is administered with a disposable needle-free injector, which uses a narrow stream of the fluid to penetrate the skin and deliver the jab to the proper tissue. Scientists say DNA vaccines are relatively cheap, safe and stable. They can also be stored at higher temperatures -- 2 to 8C. Cadila Healthcare claims that their vaccine had shown "good stability" at 25C for at least three months -- this would help the vaccine to be transported and stored easily.

The World Health Organization (WHO) said on Friday it was looking for the greatest scientific minds to advise on investigations into new high-threat pathogens that jump from animals to humans and could spark the next pandemic. From a report: Launching a request for applications, it said that its Scientific Advisory Group for the Origins of Novel Pathogens would also review progress on the next studies into the origins of the SARS-CoV-2 virus that emerged in China in late 2019. "We need to bring in the best minds here. And it needs to be multi-disciplinary," Maria van Kerkhove, head of WHO's emerging diseases and zoonosis unit, told Reuters.

The panel, announced by WHO director-general Tedros Adhanom Ghebreyesus in July, will be composed of 25 experts expected to meet first virtually in late September, a statement said. "In the last 20 years we've had many of these pathogens emerge or re-emerge: SARS, MERS, different avian influenzas, Zika, yellow fever and of course SARS-CoV-2," van Kerkhove said. Van Kerkhove, an American epidemiologist and WHO's technical lead on COVID-19, recalled that it took more than a year to establish that dromedary camels were the intermediary source of the Middle East Respiratory Syndrome (MERS) carried by bats.

Greenland just experienced another massive melt event this year. But this time, something unusual happened. It also rained at the summit of the ice sheet, [Editor's note: the link may be paywalled; alternative source] nearly two miles above sea level. From a report: Around 6 a.m. Saturday, staff at the National Science Foundation's Summit Station woke up to raindrops and water beads condensed on the station's windows. Rain occasionally falls on the ice sheet, but no staff member recalls rain -- even a light drizzle -- ever occurring at the summit before. "Basically, the entire day of Saturday, it was raining every hour that [staff] was making weather observations," said Zoe Courville, a research engineer at the Cold Regions Research and Engineering Laboratory. "And that's the first time that's been observed happening at the station."

The rain coincided with warmer temperatures that caused extensive melting across the ice sheet. Some areas were more than 18 degrees Celsius warmer than the average temperature. At the summit, temperatures peaked at 33 degrees Fahrenheit -- within a degree above freezing. The melt extent peaked at 337,000 square miles on Saturday, according to the National Snow and Ice Data Center (NSIDC). This was slightly smaller than the melting event that occurred this summer on July 28, which covered 340,000 square miles of the ice sheet, but it is still significant. Only 2012 and 2021 had multiple melt events covering more than 309,000 square miles in a year.

An anonymous reader quotes a report from ScienceDaily: Eating fructose appears to alter cells in the digestive tract in a way that enables it to take in more nutrients, according to a preclinical study from investigators at Weill Cornell Medicine and NewYork-Presbyterian. These changes could help to explain the well-known link between rising fructose consumption around the world and increased rates of obesity and certain cancers. The research, published August 18 in Nature, focused on the effect of a high-fructose diet on villi, the thin, hairlike structures that line the inside of the small intestine. Villi expand the surface area of the gut and help the body to absorb nutrients, including dietary fats, from food as it passes through the digestive tract. The study found that mice that were fed diets that included fructose had villi that were 25 percent to 40 percent longer than those of mice that were not fed fructose. Additionally, the increase in villus length was associated with increased nutrient absorption, weight gain and fat accumulation in the animals.

After observing that the villi were longer, the team wanted to determine whether those villi were functioning differently. So they put mice into three groups: a normal low-fat diet, a high-fat diet, and a high-fat diet with added fructose. Not only did the mice in the third group develop longer villi, but they became more obese than the mice receiving the high-fat diet without fructose. The researchers took a closer look at the changes in metabolism and found that a specific metabolite of fructose, called fructose-1-phosphate, was accumulating at high levels. This metabolite interacted with a glucose-metabolizing enzyme called pyruvate kinase, to alter cell metabolism and promote villus survival and elongation. When pyruvate kinase or the enzyme that makes fructose-1-phospate were removed, fructose had no effect on villus length. Previous animal studies have suggested that this metabolite of fructose also aids in tumor growth. From an evolutionary standpoint, the findings make sense. "In mammals, especially hibernating mammals in temperate climates, you have fructose being very available in the fall months when the fruit is ripe," said one of the researchers. "Eating a lot of fructose may help these animals to absorb and convert more nutrients to fat, which they need to get through the winter."

Humans, on the other hand, did not evolve to eat the amount of fructose they consume now.

An anonymous reader quotes a report from The New York Times, written by Tara Parker-Pope: Covid precautions have turned many parts of our world into a giant salad bar, with plastic barriers separating sales clerks from shoppers, dividing customers at nail salons and shielding students from their classmates. Intuition tells us a plastic shield would be protective against germs. But scientists who study aerosols, air flow and ventilation say that much of the time, the barriers don't help and probably give people a false sense of security. And sometimes the barriers can make things worse. Research suggests that in some instances, a barrier protecting a clerk behind a checkout counter may redirect the germs to another worker or customer. Rows of clear plastic shields, like those you might find in a nail salon or classroom, can also impede normal air flow and ventilation.

Under normal conditions in stores, classrooms and offices, exhaled breath particles disperse, carried by air currents and, depending on the ventilation system, are replaced by fresh air roughly every 15 to 30 minutes. But erecting plastic barriers can change air flow in a room, disrupt normal ventilation and create "dead zones," where viral aerosol particles can build up and become highly concentrated. There are some situations in which the clear shields might be protective, but it depends on a number of variables. The barriers can stop big droplets ejected during coughs and sneezes from splattering on others, which is why buffets and salad bars often are equipped with transparent sneeze guards above the food. But Covid-19 spreads largely through unseen aerosol particles. While there isn't much real-world research on the impact of transparent barriers and the risk of disease, scientists in the United States and Britain have begun to study the issue, and the findings are not reassuring.

A study published in June and led by researchers from Johns Hopkins, for example, showed that desk screens in classrooms were associated with an increased risk of coronavirus infection. In a Massachusetts school district, researchers found (PDF) that plexiglass dividers with side walls in the main office were impeding air flow. A study looking at schools in Georgia found that desk barriers had little effect on the spread of the coronavirus compared with ventilation improvements and masking. Before the pandemic, a study published in 2014 found that office cubicle dividers were among the factors that may have contributed to disease transmission during a tuberculosis outbreak in Australia. British researchers have conducted modeling studies simulating what happens when a person on one side of a barrier -- like a customer in a store -- exhales particles while speaking or coughing under various ventilation conditions. The screen is more effective when the person coughs, because the larger particles have greater momentum and hit the barrier. But when a person speaks, the screen doesn't trap the exhaled particles -- which just float around it. While the store clerk may avoid an immediate and direct hit, the particles are still in the room, posing a risk to the clerk and others who may inhale the contaminated air. [...] While further research is needed to determine the effect of adding transparent shields around school or office desks, all the aerosol experts interviewed agreed that desk shields were unlikely to help and were likely to interfere with the normal ventilation of the room. Depending on the conditions, the plastic shields could cause viral particles to accumulate in the room. The report did mention a study (PDF) by researchers with the National Institute for Occupational Safety and Health in Cincinnati that tested different sized transparent barriers in an isolation room using a cough simulator. It found that "under the right conditions, taller shields, above 'cough height,' stopped about 70 percent of the particles from reaching the particle counter on the other side, which is where the store or salon worker would be sitting or standing." However, the research was conducted under highly controlled conditions and took place in an isolation room with consistent ventilation rates that didn't "accurately reflect all real-world situations," according to the study's authors. It also "didn't consider that workers and customers move around, that other people could be in the room breathing the redirected particles and that many stores and classrooms have several stations with acrylic barriers, not just one, that impede normal air flow."

The world's first customer delivery of "green steel" produced without using coal is taking place in Sweden, according to its manufacturer. From a report: The Swedish venture Hybrit said it was delivering the steel to truck-maker Volvo AB as a trial run before full commercial production in 2026. Volvo has said it will start production in 2021 of prototype vehicles and components from the green steel. Steel production using coal accounts for around 8% of global greenhouse gas emissions. Hybrit started test operations at its pilot plant for green steel in Lulea, northern Sweden, a year ago. It aims to replace coking coal, traditionally needed for ore-based steel making, with renewable electricity and hydrogen. Hydrogen is a key part of the EU's plan to reach net zero greenhouse gas emissions by 2050.