The photosynthesizing plankton Emiliania huxleyi has a dramatic relationship with its bacterial frenemies. These duplicitous bugs help E. huxleyi in exchange for nutrients until it becomes more convenient to murder and eat their hosts. Now, scientists have figured out how these treacherous bacteria decide to turn from friend to foe.

One species of these bacteria appears to keep tabs on health-related chemicals produced by E. huxleyi, researchers report January 24 in eLife. The bacteria maintain their friendly facade until their hosts age and weaken, striking as soon as the vulnerable algae can’t afford to keep bribing them with nutrients. The finding could help explain how massive algal blooms come to an end.
The bacteria is “first establishing what we call the ‘first handshake,’” says marine microbiologist Assaf Vardi of the Weizmann Institute of Science in Rehovot, Israel. “Then it will shift into a pathogen.”

E. huxleyi’s partnership with these bacteria, which belong to a group called Roseobacter, might be best described as a love-hate relationship. The single-celled alga can’t produce the B vitamins it needs on its own, so it offers up nutrients to lure in Roseobacter that can (SN: 7/8/16). The trade is win-win — at least until the bacteria decide they’d be better off slaying and devouring their algal hosts than sticking around in peaceful coexistence.

Sometimes called the “Jekyll-and-Hyde” trait, this kind of bacterial backstabbery shows up everywhere from animal guts to the open seas. But it wasn’t clear before how Roseobacter decide it’s the right moment to murder E. huxleyi.

Vardi’s team exposed a type of Roseobacter that lives with E. huxleyi to chemicals taken from algae that were either young and growing or old and stagnant. The team also introduced the bacteria to extra doses of a certain health-signaling algal chemical.Looking at which genes the bacteria activated in the different experiments revealed how and why they switched from friend to foe.

The bacteria kill their algal pals when exposed to high concentrations of a sulfur-containing chemical called DMSP, the researchers found. E. huxleyi leaks more and more DMSP as it ages. This eventually cues its duplicitous microbial partners to go rogue, kill their aging host, and kick their genes for nutrient-grabbing proteins and flagella — whiplike tails used to swim — into overdrive.

It’s an “eat-and-run strategy,” says Noa Barak-Gavish, a microbiologist at ETH Zurich. “You eat up whatever you can and then swim away to avoid competition … [and] to find alternative hosts.”

DMSP isn’t the only figure in this deadly chemical calculus. E. huxleyi can sate its companion’s bloodlust with a bribe of benzoate, a nutrient that Roseobacter can use but most bacteria can’t.

While it’s clearer now what drives the bacteria to kill their hosts, their murder weapon remains a mystery. Vardi says his group has some hunches to follow up on.

This kind of frenemies relationship could be a key factor in controlling the boom and bust of massive algal blooms if other phytoplankton and bacteria have a similar dynamic, says Mary Ann Moran of the University of Georgia in Athens, who was not involved in the study. Algal blooms can be toxic (SN: 8/28/18). But they also “fix” enormous amounts of carbon dioxide into biomass and are a major source of organic carbon to the ocean.
“Phytoplankton fix half of all the carbon on the planet, and probably 20 percent to 50 percent of what they fix … actually goes right to bacteria,” she says. So if this kind of relationship controls how carbon flows through the ocean, “that is something that we would really like to understand.”

Vikings brought horses and dogs to the British Isles from Scandinavia, a new study suggests.

A chemical analysis of bone fragments from a cemetery in England provides the first solid scientific evidence of animals traveling with Vikings across the North Sea, scientists report February 1 in PLOS ONE.

In the 1990s, researchers unearthed the cremated remains of a human adult and child as well as of a dog, horse and probable pig from a burial mound in a Viking cemetery in Derbyshire, England. In previous work, radiocarbon dating of femur, skull and rib fragments revealed that the inhabitants all died sometime between the eighth and 10th centuries. That date was narrowed down to the year 873, thanks to the ninth-century Anglo-Saxon Chronicle, which records that a Viking army wintered near the site that year.
Where the animals came from has been a mystery. Norse raiders are known to have stolen horses from people in England around the time. And researchers have generally thought that Viking boats at the time were too small to allow for much transport of animals from Scandinavia to the British Isles. One entry in the Anglo-Saxon Chronicle describes Vikings moving from France to England along with their horses in the year 892, but no physical evidence of such activity had been found before.

In the new work, Tessi Löffelmann and colleagues turned to certain forms, or isotopes, of strontium to unravel the individuals’ provenance. The element accumulates in bones over time through diet, leaving a distinct signature of where an individual has lived (SN: 4/2/19).
Strontium ratios in the child’s remains matched those of shrubs growing at the burial site, suggesting the child spent most, if not all, of its life in England. The ratios of the adult and three animals, on the other hand, differed substantially from the local fauna, the team found. That suggests the individuals hadn’t spent much time in the country before they died. Instead, their ratios were similar to ones found in the Baltic Shield region in Norway, central and northern Sweden and Finland, suggesting a Scandinavian origin.

“One of the joys of isotope analysis is that you are able to really pinpoint things that previously we could discuss endlessly,” says Marianne Moen, an archeologist at the University of Oslo who was not involved in the study. Using strontium to analyze more cremated remains, which can elude common forms of isotope analysis including carbon and nitrogen, “is the next logical chapter for understanding prehistoric mobility.”

Isotope analysis helped reveal where these individuals lived and when they died, but it couldn’t answer why the dog, horse and pig made the journey to England in the first place. That’s where historical records can help, says Löffelmann, of Durham University in England and Vrije Universiteit Brussel in Belgium.

For Löffelmann, the small sizes of early Norse ships combined with the fact that the animals and people were buried together suggest Vikings may have initially brought animals with them for companionship, not just function.

“It could have only been selected animals that made that journey,” she says. “They were important to what the person was.… They went through life together, and now they’re going through death.”

Scientists have unwrapped long-sought details of embalming practices that ancient Egyptians used to preserve dead bodies.

Clues came from analyses of chemical residue inside vessels from the only known Egyptian embalming workshop and nearby burial chambers. Mummification specialists who worked there concocted specific mixtures to embalm the head, wash the body, treat the liver and stomach, and prepare bandages that swathed the body, researchers report February 1 in Nature.

“Ancient Egyptian embalmers had extensive chemical knowledge and knew what substances to put on the skin to preserve it, even without knowing about bacteria and other microorganisms,” Philipp Stockhammer, an archaeologist at Ludwig Maximilians University of Munich, said at a January 31 news conference.
The findings come courtesy of chemical residue inside 31 vessels found in an Egyptian embalming workshop and four vessels discovered in an adjacent pair of burial chambers. Writing on workshop vessels named embalming substances, provided embalming instructions (such as “to put on his head”) or both. All the artifacts — dating from Egypt’s 26th dynasty which rose to power between 664 B.C. and 525 B.C. — were excavated at a cemetery site called Saqqara in 2016. Archaeologist and study coauthor Ramadan Hussein, who died in 2022, led that project.

Newfound mummy embalming mixtures
Five of the vessels had the label antiu. The substance was thought to have been a fragrant resin called myrrh. The antiu at Saqqara, however, consisted of oil or tar from cedar and juniper or cypress trees mixed with animal fats. Writing on these jars indicates that antiu could have been used alone or combined with another substance called sefet.

Three vessels from the embalming workshop bore the label sefet, which researchers have usually described as an unidentified oil. At Saqqara, sefet was a scented, fat-based ointment with added ingredients from plants. Two sefet pots contained animal fats mixed with oil or tar from juniper or cypress trees. A third container held animal fats and elemi, a fragrant resin from tropical trees.

Clarification of the ingredients in antiu and sefet at Saqqara “takes mummification studies further than before,” says Egyptologist Bob Brier of Long Island University in Brookville, N.Y., who was not part of the research.

Egyptians may have started mummifying their dead as early as 6,330 years ago (SN: 8/18/14). Mummification procedures and rituals focused on keeping the body fresh so the deceased could enter what was believed to be an eternal afterlife.
Embalming and mummification procedures likely changed over time, says team member Maxime Rageot, a biomolecular archaeologist also at Ludwig Maximilians University. Embalmers’ mixtures at Saqqara may not correspond, say, to those used around 700 years earlier for King Tutankhamun (SN: 11/2/22).

Mummy embalming instructions
Outside surfaces of other vessels from the Saqqara embalming workshop and burial chambers sported labels and, in some cases, instructions for treatment of the head, preparation of linen mummy bandages, washing the body and treating the liver and stomach. Inscriptions on one jar referred to an administrator who performed embalming procedures, mainly on the head.

Chemical residue inside these pots consisted of mixtures specific to each embalming procedure. Ingredients included oils or tars of cedar and juniper or cypress trees, pistachio resin, castor oil, animal fats, heated beeswax, bitumen (a dense, oily substance), elemi and a resin called dammar.

Most of those substances have been identified in earlier studies of chemical residues from Egyptian mummies and embalming vessels in individual tombs, says Egyptologist Margaret Serpico of University College London. But elemi and dammar resins have not previously been linked to ancient Egyptian embalming practices and are “highly unexpected,” notes Serpico, who did not participate in the new study.

Elemi was an ingredient in the workshop mixtures used to treat the head, the liver and bandages wrapped around the body. Chemical signs of dammar appeared in a vessel from one of the burial chambers that included remnants of a range of substances, indicating that the container had been used to blend several different mixtures, the researchers say.

Specific properties of elemi and dammar that aided in preserving dead bodies have yet to be investigated, Stockhammer said.

A far-flung trade network for mummy embalming ingredients
Elemi resin reached Egypt from tropical parts of Africa or Southeast Asia, while dammar originated in Southeast Asia or Indonesia, Rageot says. Other embalming substances detected at Saqqara came from Southwest Asia and parts of southern Europe and northern Africa bordering the Mediterranean Sea. These findings provide the first evidence that ancient Egyptian embalmers depended on substances transported across vast trade networks.

Egyptian embalmers at Saqqara took advantage of a trade network that already connected Egypt to sites in Southeast Asia, Stockhammer said. Other Mediterranean and Asian societies also engaged in long-distance trade during ancient Egypt’s heyday (SN: 1/9/23).

It’s no surprise that ancient Egyptians imported embalming ingredients from distant lands, Brier says. “They were great traders, had limited [local] wood products and really wanted these substances to achieve immortality.”

A crucial link in the life cycle of one parasitic plant may be found in a surprising place — the bellies of the descendants of an ancient line of rabbits.

Given their propensity for nibbling on gardens and darting across suburban lawns, it can be easy to forget that rabbits are wild animals. But a living reminder of their wildness can be found on two of Japan’s Ryukyu Islands, if you have the patience to look for it: the endangered Amami rabbit, a “living fossil” that looks strikingly similar to ancient Asian rabbits.
One estimate suggests there are fewer than 5,000 of the animals left in the wild. The lives of Amamis (Pentalagus furnessi) are shrouded in mystery due to their rarity, but they seem to play a surprising ecological role as seed dispersers, researchers report January 23 in Ecology.

Seed dispersal is the main point in a plant’s life cycle when it can move to a new location (SN: 11/14/22). So dispersal is crucially important for understanding how plant populations are maintained and how species will respond to climate change, says Haldre Rogers, a biologist at Virginia Tech in Blacksburg, who was not involved with the study. Despite this, seed dispersal hasn’t received much attention, she says. “We don’t know what disperses the seeds of most plants in the world.”

Locals from the Ryukyu Islands were the first to notice that the “iconic yet endangered” Amami rabbit was nibbling on the fruit of another local species, the plant Balanophora yuwanensis, says Kenji Suetsugu, a biologist at Kobe University in Japan.

Rabbits generally like to eat vegetative tissue from plants, like leaves and stems, and so haven’t been thought to contribute much to spreading seeds, which are often housed in fleshy fruits.

To confirm what the locals reported, Suetsugu and graduate student Hiromu Hashiwaki set up camera traps around the island to catch the rabbits in the act. The researchers were able to record rabbits munching on Balanophora fruits 11 times, but still needed to check whether the seeds survived their trip through the bunny tummies.
So the team headed out to the subtropical islands and scooped up rabbit poop, finding Balanophora seeds inside that could still be grown. By swallowing the seeds and pooping them out elsewhere, the Amami rabbits were clearly acting as seed dispersers.

Balanophora plants are parasitic and don’t have chlorophyll, so they can’t use photosynthesis to make food of their own (SN: 3/2/17). Instead, they suck energy away from a host plant. This means where their seeds end up matters, and the Amami rabbits “may facilitate the placement of seeds near the roots of a compatible host” by pooping in underground burrows, Suetsugu says. “Thus, the rabbits likely provide a crucial link between Balanophora and its hosts” that remains to be further explored, he says.
Understanding the ecology of an endangered species like the Amami rabbit can help with conserving both it and the plants that depend on it.

An animal need not be in obvious peril for a change in its number to affect seed dispersal, with potentially negative consequences for the ecosystem. For example, “we think of robins as super common … but they’ve declined a lot in the last 50 years,” Rogers says. “Half as many robins means half as many seeds are getting moved around, even though no one’s worried about robins as a conservation issue.”

No backside, no problem for some young sea spiders.

The creatures can regenerate nearly complete parts of their bottom halves — including muscles, reproductive organs and the anus — or make do without them, researchers report January 23 in Proceedings of the National Academy of Sciences.

The ability to regrow body parts isn’t super common, but some species manage to pull it off. Some sea slug heads can craft an entirely new body (SN: 3/8/21). Sea spiders and some other arthropods — a group of invertebrates with an exoskeleton — can regrow parts of their legs. But researchers thought new legs were the extent of any arthropod’s powers, perhaps because tough exteriors somehow stop them from regenerating other body parts.
A mishap first clued evolutionary biologist Georg Brenneis in that sea spiders (Pycnogonum litorale) might be able handle more complex repairs too. He accidentally injured one young specimen that he was working on in the lab with forceps. “It wasn’t dead, it was moving, so I just kept it,” says Brenneis, of the University of Vienna. Several months later, the sea spider had an extra leg instead of a scar, he and evolutionary biologist Gerhard Scholtz of Humbolt University of Berlin reported in 2016 in The Science of Nature.

In the new study, most of the 19 young spiders recovered and regrew missing muscles and other parts of their lower halves after amputation, though the regeneration wasn’t always perfect. Some juveniles sported six or seven legs instead of eight.

None of four adults regenerated. That may be because adults no longer shed their skin as they grow, suggesting that regeneration and molting are somehow linked, Brenneis says. Two young sea spiders also didn’t regenerate at all. The animals survived with only four legs and without an anus. Instead of pooping, the pair regurgitated waste out of their mouths.
Next up is figuring out whether other arthropods also regenerate more than scientists thought, and how sea spiders do it, Brenneis says. “I would like to see how it works.”

A new smartwatch app alerts users who are deaf or hard of hearing of nearby sounds, such as microwave beeps or car horns.

“The main motivation [for the app] came from my own experience, and conversations that my colleagues and I have had with deaf and hard of hearing people over several years,” says Dhruv Jain, who presented the system, called SoundWatch, at the virtual ASSETS conference on October 28.

Jain, who is hard of hearing, uses SoundWatch at home to avoid sleeping through a smoke alarm. “On a nature walk, it’ll tell me that there’s birds chirping, or there might be a waterfall nearby,” he says. “Those sounds make me feel more present and connected to the world.”

Sound awareness apps for smartphones exist. But Jain prefers the immediacy of sound notifications on his wrist, rather than in his pocket — and surveys of people who are deaf or hard of hearing show he’s not alone.

The SoundWatch app pairs an Android smartwatch and phone. The watch records ambient noises and sends that data to the phone for processing. When the phone detects a sound of interest, the smartwatch vibrates and displays a notification.

Jain, a computer scientist at the University of Washington in Seattle, and colleagues designed the app to identify 20 noises. In experiments, SoundWatch correctly identified those 20 sounds 81.2 percent of the time. When set to listen only for urgent noises — a fire alarm, door knock or alarm clock — the app was 97.6 percent accurate. Eight deaf and hard of hearing people who used SoundWatch around a university campus gave the app broadly favorable reviews, but noted that the app misclassified some sounds in noisy outdoor settings.

Jain and colleagues are now working on a version of SoundWatch that users can train to recognize new sounds, such as their own house alarm, using just a few recordings.

November is beginning to feel a lot like last March.

In Europe, where the coronavirus was largely under control for much of the summer and fall, cases are skyrocketing nearly everywhere. Twenty countries, including the United Kingdom and France, have shuttered restaurants, introduced curfews or generally urged people to stay at home, though most schools and universities are staying open for now.

Cases are surging across the United States, too, where more than 100,000 new infections are being reported each day. Already in November, more than half of states have set records for the most cases in a week, and in places such as Minnesota, Utah and Wisconsin, some hospitals are nearing capacity. In North Dakota, nearly 1 in every 14 people has already contracted the coronavirus, with 2,254 cases reported November 8 alone in a state of 762,000 people.

To make matters worse, “the virus is going into its sweet spot at a time that we’re exhausted by it,” says Jeffrey Shaman, an infectious diseases epidemiologist at the Columbia University Mailman School of Public Health in New York City. That sweet spot is indoors, where people are spending more time as the weather in the Northern Hemisphere turns colder — and where the virus can spread more easily.

Despite such a grave outlook, experts say it’s still not too late to turn the tide.

Shutting down borders, businesses and schools are among the most drastic measures to do that. Worries over economic consequences may hold governments back from issuing widespread stay-at-home orders this time around, though.

U.S. President-elect Joe Biden, who unveiled a COVID-19 advisory board November 9, has proposed a multipronged plan for controlling the pandemic, including nationwide mask mandates and expanded testing. But Biden won’t take office until January 20, and President Donald Trump has repeatedly downplayed the surge in cases.

While getting a COVID-19 vaccine — or vaccines — is closer than ever (SN: 11/9/20), most experts agree that vaccines probably won’t be available to everybody until late spring or early summer.
That means getting through the winter will require falling back on the familiar public health tools of physical distancing, mask wearing, and testing and isolating infected people, Shaman says. But all of those measures fall short unless everyone is willing to follow the rules.

Living in this reality can be draining, acknowledges Aleksandra Zając, a doctor specializing in nuclear medicine in Warsaw. Doctors and patients alike are tired of not being able to leave their homes and having to wear a mask when they do, she says, but “as a doctor, I really see the need for all those restrictions.” People aren’t helpless against the virus, she says. “We still have some impact on what’s going on.”
Zając devised a calculator to help people learn how much wearing masks and goggles, regularly washing their hands and keeping distance from others might help protect them. Alone, none of those measures is perfect, but doing them all together can boost protection, like layering slices of Swiss cheese so that holes in one slice are covered by another slice. The Swiss cheese idea is not new, but it’s still relevant for stacking public health measures, Zając says. It goes for individual actions, too.

“One individual cannot do much” beyond protecting themselves, Zając says, “but if we sum up all the individuals together and they all follow the rules, I truly believe we can control this pandemic.”

Scientists know much more about the virus than they did in March, and that knowledge can help make the most of all the public health tools at our disposal.

Mask up
Dozens of studies have made it abundantly clear that wearing a mask is one of the most effective steps an individual can take to help curb the pandemic. Masks are especially crucial in lessening the risk of someone who doesn’t know they’re infected passing the virus to someone else (SN: 6/26/20).

Additionally, there’s a growing understanding among scientists that masks are good for the wearer too. The U.S. Centers for Disease Control and Prevention updated their scientific guidance on November 10 to acknowledge that cloth masks can reduce the number of infectious droplets inhaled by the wearer, which offers a degree of protection, especially when masks are multi-layered.

In a study published October 23 in Nature Medicine, scientists estimate that if 95 percent of people wore masks when outside their homes, nearly 130,000 deaths from COVID-19 might be averted in the United States between the end of September and the end of February 2021. If 85 percent of people wear masks, about 96,000 lives might be saved, the researchers calculate.

The debate over which kind of mask is best, however, has been spirited (SN: 8/12/20).

When it comes to ubiquitous cloth masks, only one randomized clinical trial in the world is testing their effectiveness in preventing COVID-19. That trial in Guinea-Bissau is giving all 66,000 expected participants advice about how to avoid respiratory illnesses. Half of those people will each also get two locally sewn cloth masks. The trial is expected to wrap up in November.

Some research on the prevention of other respiratory illnesses suggests that a cloth mask’s effectiveness depends on many factors, including wearing the mask properly over both the nose and mouth. Regular washing in hot water is also necessary, says Raina MacIntyre, a mask researcher at the University of New South Wales in Sydney.
In 2015, she and colleagues published in BMJ Open results of a trial conducted in Hanoi, Vietnam. Roughly 1,600 health care workers at 15 hospitals were assigned to either wear a medical mask at all times during their shift, to wear a two-layer cloth mask or to follow the hospital’s standard practice, which may or may not involve wearing a mask. The results weren’t encouraging. At the end of the five-week study, people in the cloth mask group had the highest rate of respiratory infections, such as colds — even higher than the group that wasn’t regularly wearing masks. The researchers concluded that health care workers shouldn’t wear cloth masks and opt instead for medical masks.

The trial was very controversial, MacIntyre says, “because the message was that cloth masks could be dangerous. That caused a lot of angst during the pandemic. In March and April, I had a lot of health workers in the U.S. and Europe contacting me and saying, ‘The hospital has run out of respirators. Is it better I wear no mask than wear a cloth mask?’”

That prompted MacIntyre and colleagues to examine unpublished data from the trial. Both surgical and cloth masks get contaminated with respiratory viruses, the researchers found. But surgical masks are disposable. If people didn’t wash their reusable cloth masks every day, the masks became more and more contaminated.

“If you washed your cloth mask in a washing machine with hot water, you were just as protected as wearing a surgical mask,” MacIntyre says. But workers who hand-washed their masks had double the risk of infection of those wearing a medical mask, the researchers reported September 28 in BMJ Open.
“The bottom line is, the washing is part of the protective effect of a cloth mask,” MacIntyre says. She recommends a daily wash in water at 60° to 90° Celsius, far hotter than anyone could stand to hand-wash. Shrinkage from hot water also tightens up pores in the mask, keeping the virus from slipping through easily.

Health care workers should also wear protective goggles to prevent rare cases of infection through the eye, MacIntyre says. But determining whether people going about their daily lives need goggles, face shields or other eye protection in addition to masks is a tricky bit of calculus, she says. “You have to look at community transmission rates. You have to look at where you’re actually going. Are you just going for a walk outside or are you going to a doctor’s surgery and are going to be sitting in an unventilated waiting room for two hours?”

The best most people can do is to take all the precautions they can, including avoiding large gatherings — especially indoors — wearing masks and keeping distance from people they don’t live with.

Fine-tuning lockdowns
Early in the pandemic, lockdowns and social distancing measures (of varying severity) enacted in many countries largely worked. Staying at home starved the virus of transmission opportunities, preventing over 500 million infections in six hard-hit countries, according to some experts (SN: 6/9/20).

Circumstances are different now. “I don’t think we’ll lock down at that scale again,” says Michael Osterholm, an epidemiologist at the University of Minnesota in Minneapolis and a member of Biden’s task force. Now that scientists have a better understanding of transmission, blanket lockdowns may not be needed. Instead, restrictions could focus on crowded, poorly ventilated spaces like restaurants and bars.

If cases continue to grow exponentially, however, stricter lockdowns may be the only tool left to prevent hospitals from being overwhelmed. But such measures are increasingly less palatable to many Americans, Osterholm says. “What the public will accept is key. If they won’t comply, it doesn’t really matter what you recommend or how you recommend it.”

Limits of lockdowns
Stay-at-home orders also don’t stop transmission within a household, where experts are learning that the virus can rapidly spread. In a sample of 101 homes with a positive coronavirus test, 53 percent of other people living in those homes became quickly infected, researchers reported in the Nov. 6 Morbidity and Mortality Weekly Report.

“We know that it’s really gatherings in close contact indoors that are riskiest,” says Alison Hill, an epidemiologist at Johns Hopkins University. “There’s no reason why if you’re in your own house or among family or friends to think that the disease can’t spread.” Isolating infected members of a household, wearing masks and improving ventilation can limit household transmission, she says.

And not everyone can stay home, which has contributed to inequities in who is getting sick in this pandemic.

In the United States, residents of poorer neighborhoods, often home to racial and ethnic minorities disproportionately affected by COVID-19 (SN:4/10/20), were less likely to stay at home during the early months of the pandemic than residents of richer neighborhoods. Cell phone mobility data suggest that this difference stems from work-related demands, according to a study published November 3 in Nature Human Behavior. Residents of the highest-income neighborhoods reduced days at work outside the home by 13.7 percent, compared with 6.6 percent for residents of lower-income neighborhoods, Jonathan Jay, a public health researcher at Boston University, and colleagues found.

Many residents of lower-income neighborhoods work jobs that can’t be done from home. But when there was a choice, people in these neighborhoods did limit their activities, Jay says. The data showed that people of all income groups reduced outings unrelated to work at roughly similar levels.

Policies like restricting evictions so people don’t fear losing their home if they miss work, expanding unemployment insurance and mandating paid sick leave could help these residents physically distance, Jay says.

Test and trace
Lockdowns by themselves will not end the pandemic. They are only supposed to be temporary measures that buy time for local and state health departments to beef up other infection-control strategies. Crucial among these are testing and contact tracing, a tried-and-true public health intervention whereby contacts of positive cases are quickly identified and instructed to quarantine (SN: 4/29/20).

“Contact tracing is really key when you have a disease that’s as fast-spreading as COVID-19,” because it breaks crucial chains of transmission, says Martial Ndeffo, an infectious diseases researcher at Texas A&M University in College Station.

Contact tracing and isolation is most powerful when cases are identified early in the course of infection, their contacts are traced and informed of their exposure quickly, and those contacts comply with requests to quarantine. Such a system requires broadly available testing and lots of contact tracers to do the detective work.
Otherwise, even with relatively small caseloads, contact tracing systems can’t keep up with a growing epidemic. At this point, most of the United States can’t keep up. In October, only three states and the District of Columbia had enough full-time contact tracers to deal with current caseloads, according to a survey conducted by NPR and the Johns Hopkins Center for Health Security. And as cases climb, even well-staffed systems could be overwhelmed.

“Given the number of cases in the U.S., it is unrealistic to think that most states have the resources and available staff to raise the army of contact tracers needed,” Ndeffo says. Biden’s COVID-19 response plan includes efforts to “mobilize at least 100,000 Americans across the country” to boost the contact tracing effort. Currently, there are just over 50,000 contact tracers nationwide.

Robust contact tracing systems work only if people comply with public health officials and share their contact history or quarantine if necessary. Yet only 58 percent of Americans would be likely to speak with a public health official who contacted them by phone or text message about the coronavirus outbreak, according to a Pew Research survey released October 30. “A substantial number of people do not comply with or provide adequate information needed for contact tracing to be effective,” Ndeffo says. Clearer and more consistent public health messaging could improve these numbers.

Time is of the essence
It’s important to act quickly to introduce social distancing measures when case counts begin to surge, as they are now in the United States and Europe, Shaman says, because outbreaks grow at exponential rates. “Exponential growth leads to a tsunami-like effect; it gets worse the longer you wait on it.”

He and colleagues simulated what would have happened had states done exactly what they did at the beginning of the U.S. epidemic in March, only earlier. Enacting social distancing and stay-at-home orders on March 1 instead of March 8 would have headed off about 600,000 confirmed cases and 32,000 deaths. Acting two weeks earlier would have avoided more than 1 million cases and about 60,000 deaths nationwide, Shaman and colleagues reported November 6 in Science Advances.

No one can turn back the clock. But countries including Vietnam, Taiwan, Singapore, New Zealand and Australia have shown that acting aggressively can curb the spread of the virus. “Going forward, the longer you delay in acting on this virus the more damage it does,” both to people who are infected and to the economy, Shaman says.

For instance, at the end of September, 89 counties in Tennessee eased or removed social distancing restrictions. But as COVID-19 cases rose, traffic to bars and restaurants decreased, researchers from Vanderbilt University in Nashville report. Cell phone mobility data as of October 21 suggest that business dropped once restrictions were lifted and was 24 percent below where it was during the same time in 2019. Those findings suggest that infection rates, not restrictions, have a bigger effect on people’s choices, the researchers conclude.

“If you don’t control the virus,” Shaman says, “you’re not going to have an economy.”

A long-sought “holy grail” in cryptography is poised to change the way we protect sensitive information.

Today’s standard encryption schemes take an all-or-nothing approach. Once scrambled, your data become inaccessible to anyone without the secret key.

This has allowed for secure e-mail communication, the proliferation of online transactions and digital signatures. It allows tax and medical records with sensitive personal information to be passed more safely across the internet. But if you give someone the secret key to access any of the data, all of the data become vulnerable.

What if instead you could assign specific people access to do very specific things with your data? Someone could get the information they need (the info you want them to have) without unlocking all of the original data. Bank details, credit card numbers, account passwords – all would remain hidden. That wholly different approach could also allow Netflix to make show recommendations without seeing your full viewing history, for example. Google could sort your e-mails without knowing what’s in them. And medical researchers could analyze data to identify risk factors for a disease without accessing any individual’s health information.

This and other cryptographic wonders now appear possible through a master tool called indistinguishability obfuscation.

“It’s a new tool – a very powerful tool,” says cryptographer Huijia (Rachel) Lin of the University of Washington in Seattle who showed with colleagues in 2020 how to construct the tool. “Once you have this superstrong power, then a lot of the other tasks are either special cases of it, or you can easily use this to realize [those tasks].”

Vinod Vaikuntanathan, a computer scientist at MIT who has worked with Lin on previous research, compares indistinguishability obfuscation, or iO, to a grand theory in physics that would unite gravity and quantum mechanics. “iO gives you a way to do a grand unification of cryptography in the sense that you can explain much of what cryptography does in a very simple way.”
Standout research
Indistinguishability obfuscation is a form of program obfuscation, an approach that seeks to hide the inner workings of a computer program, not just the message or data itself. Though proposed in 1976 in a paper that set the foundation for modern cryptography, program obfuscation proved difficult to achieve. For many years, people thought it might not be possible.

And in 2001, researchers showed that complete program obfuscation — called black-box obfuscation, in which input and output data are known but nothing else about a program can be discovered — is impossible. Yet indistinguishability obfuscation, proposed at the same time and shown to be incredibly powerful, doesn’t demand that everything about a program remain hidden. It instead deals with two programs that perform the same function. If the inner workings of those two programs can be hidden enough that the two can’t be distinguished from each other, indistinguishability obfuscation has been achieved. By hiding the secret key within the program itself, iO enables the delegation of specific data and data tasks to specific people.

Still, proposal after proposal for making iO work proved breakable. Researchers couldn’t figure out how to keep it safe from an adversary’s attacks. Lin says the approaches being used didn’t appeal to her. Researchers were leaning on what appeared to be “good enough” ways of getting at the problem that weren’t backed by rigorous mathematical proofs.

Lin instead wanted to break the problem down so she could understand each component and how they worked together. She wanted to approach the problem like a clock, with gears and nuts and bolts, instead of tangled like “a bowl of spaghetti.”

Through this strategy, Lin, along with Amit Sahai of UCLA and Aayush Jain, a Ph.D. student at UCLA at the time, demonstrated that iO is achievable. It would be secure based on standard assumptions in the field, the team proved, renewing hope in the tool.

“Of course, [Huijia] is brilliant,” Vaikuntanathan says, adding that her persistence is what really sets her apart. “It takes some guts to continue with an approach when essentially all the rest of the world thinks that it is not going to work.”

Backstory
Lin says she didn’t grow up with computers or fall in love with computer programming at an early age. As a student, she was interested in physics and strived to be good at everything. She started with computer science in college; a class in cryptography as a Ph.D. student at Cornell University “was really mind-opening,” she says. Her introduction to what are known as zero-knowledge proofs stands out in her memory.

A zero-knowledge proof says that a person can convince someone else that they know a secret without revealing the secret or any details about it. Say, for example, you knew that a number was the product of two prime numbers. Can you convince someone that fact is true without revealing what the primes are? How to prove that such a task is possible fascinated Lin.
Cryptography includes a lot of these seeming paradoxes that prove to be possible. Indistinguishability obfuscation is yet another example – and Lin works on others, including secure multiparty computation, which allows a computer task to run across multiple people’s data without any person having to reveal their data to anyone in the group, or to a third party.

“I’m very attracted to these magical concepts,” Lin says. “The fun of it is to make this concept come to realization.”

Indistinguishability obfuscation is still far from real-world implementation. But Vaikuntanathan says it’s not unusual for first constructions of what will become important approaches to be impractical at first. “Wait for a decade,” he says.

Environmental engineer Smruthi Karthikeyan had spent just a couple of days working in her new lab at the University of California, San Diego when the state instituted its first coronavirus lockdown in March 2020.

She’d been brought on as a postdoc by biologist Rob Knight to develop new techniques for studying how microbes in complex ecosystems shape human health and vice versa. The COVID-19 pandemic quickly put a new spin on that mission.

Soon, the lab pivoted to support the coronavirus response. Infections were outpacing testing capacity in San Diego County, Karthikeyan says. Meanwhile, the university wanted to keep the campus open for its 10,000 students still living on campus and 25,000 workers. There had to be a way to monitor infections without requiring thousands of people to get tested all the time, Karthikeyan and colleagues thought.

Public health researchers had previously tested wastewater for pathogens as a way to spy on the movements of infectious agents in communities. Viruses, bacteria and parasites can show up in stool before people exhibit symptoms, giving clues to a coming outbreak. But no one had implemented such a system to track a respiratory virus before, and never at a scale of tens of thousands of people.

Karthikeyan was up for the challenge.

Bold idea
The wastewater monitoring system that Karthikeyan and colleagues developed and implemented at UC San Diego, reported July 7 in Nature, processes upward of 200 samples per day. Previous methods could process a maximum of eight samples, she says. What’s more, the system has identified newly spreading coronavirus variants up to two weeks earlier than clinical testing and accurately forecasted the mix of variants infecting students and staff.

That has given school officials more time to take action to keep infection rates low. During the study period from November 2020 to September 2021, the proportion of clinical tests that were positive was less than one percent, Karthikeyan says, dramatically lower than rates in the surrounding area and many other college campuses at the time.
Among the key players in the team’s monitoring system are 131 robots that collect wastewater samples throughout each day from 360 university buildings. Back at the lab, the samples are screened for viral RNA and results are fed into a publicly available online dashboard created as part of the project.

Karthikeyan’s team isn’t the only one using human waste to get a jump on COVID-19. But the scale of the monitoring “is a bit unprecedented,” says Ameet Pinto, an environmental engineer at Georgia Tech in Atlanta. During the study period, Karthikeyan and colleagues processed a total of nearly 20,000 samples. “That’s amazing,” he says.

A positive result triggers a campus-wide notification via smartphone app. For dorms, anyone who lives in the building is mandated to get tested for COVID-19, while anyone who may have recently been in the building is strongly encouraged to get tested.

To increase access to tests, the team swapped candy in vending machines for at-home test kits and installed test drop boxes in the buildings. Karthikeyan’s team processes the tests and sends results within a day.

Anyone testing positive for the coronavirus is moved to a designated isolation dorm or instructed to isolate at home if they live off campus. If the coronavirus shows up in the next day’s wastewater test, the building’s remaining occupants will receive a notification to test again.

To figure out which variants are causing infections at the university, Karthikeyan’s team built a freely available computational tool called Freyja. It uses a library of genetic markers to identify the relative abundances of well-known and emerging variants in the wastewater. Freyja detected the emerging delta variant on campus 14 days before clinical tests did, Karthikeyan and colleagues report.

Growing the effort
Based on success at the university, San Diego County officials asked the researchers to test a modified version of the system at the Point Loma Wastewater Treatment Plant, which serves more than 2.2 million residents, and at 17 public schools. Elementary school students got to name the robots, dubbing the machines Sir-Poops-a-Lot, Harry Botter and the Rancid Water, and other silly monikers, Karthikeyan said with a chuckle.

On the county level, the system detected the emergence of the omicron variant 11 days before clinical testing, the team reports in the same study in Nature. A detailed analysis of the public school data hasn’t yet been published.

Karthikeyan and colleagues’ methods have been adapted by researchers at the state, national and international levels. For instance, the U.S. Centers for Disease Control and Prevention and the Food and Drug Administration use Freyja to track variants in wastewater across the country.

The system is now being used to monitor monkeypox, and the team is working on how it can detect other pathogens that may be spreading unnoticed. That work has the potential to have a huge impact on wastewater epidemiology, Pinto says.

Karthikeyan will launch her own lab at Caltech in 2023, where she plans to adapt these tools for monitoring groundwater. Communities of microbes that live there can serve as sentinels, flagging disturbances from pollution, climate change and more, she says. “My whole thing is to look at a much larger system from a very tiny lens.”

Some of the earliest stars yet seen are now coming to light in one of the first images from the James Webb Space Telescope.

Formed roughly 800 million years after the Big Bang, the stars live in dense groups called globular clusters and surround a distant galaxy dubbed the Sparkler, astronomers report in the Oct. 1 Astrophysical Journal Letters. Globular clusters often host some of the oldest stars in contemporary galaxies such as our own, but it’s hard to tell their exact age. The new finding could help researchers pinpoint when such clusters began to form.

Compared to a galaxy, globular clusters are tiny, which makes them hard to see from across the universe. But this time, a gargantuan natural lens in space helped. The Sparkler is one of thousands of galaxies that lie far behind a massive, much closer galaxy cluster called SMACS 0723, which was the subject of the first publicly released science image from the James Webb Space Telescope, or JWST (SN: 7/11/22). The cluster distorts spacetime such that the light from the more distant galaxies behind it is magnified.

For all those remote galaxies, that extra magnification brings out details that have never been seen before. One elongated galaxy surrounded by yellowish blobs got the attention of astronomer Lamiya Mowla and her colleagues.

“When we first saw it, we noticed all those little dots around it that we called ‘the sparkles,’” says Mowla, of the University of Toronto. The team wondered if the sparkles could be globular clusters, close-knit families of stars that are thought to have been born together and stay close to each other throughout their lives (SN: 10/15/20).

“The outstanding question that there still is, is how were the globular clusters themselves born?” Mowla says. Were they born at “cosmic noon,” 10 billion years ago, when star formation throughout the universe peaked? Or did they form 13 billion years ago at “cosmic dawn,” when stars were first able to form at all (SN: 3/4/22)?

Light from the Sparkler takes about 9 billion years to reach Earth, so if the sparkles are globular clusters that shone that long ago, they might help astronomers answer that question.
Mowla and her colleagues used data from JWST to analyze the wavelengths of light coming from the sparkles. Some of them appear to be forming stars at the time when their light left the clusters. But some had formed all their stars long before.

“When we see them, the stars are already about 4 billion years old,” says astrophysicist Kartheik Iyer, also of the University of Toronto.

That means the oldest stars in the sparkles could have formed roughly 13 billion years ago. Since the universe is 13.8 billion years old, “there’s only a short amount of time after the Big Bang when these could have formed,” he says.

In other words, these clusters were born at dawn, not at noon.

Studying more globular clusters around ancient galaxies could help determine if such clusters are common or rare early on in the universe’s history. They could also help unravel galaxies’ formation histories, say Mowla and Iyer. Their team has proposed observations to be made in JWST’s first year that could do just that.

Being able to pick out tiny structures like globular clusters from so far away was almost impossible before JWST, says astronomer Adélaïde Claeyssens of Stockholm University. She was not involved in the new work but led a similar study earlier this year of multiple galaxies magnified by the SMACS 0723 cluster.

“It’s the first time we showed that, with James Webb, we will observe a lot of these type of galaxies with really tiny structures,” Claeyssens says. “James Webb will be a game changer for this field.”