A chicken eggshell has a tricky job: It must protect a developing chick, but then ultimately let the chick break free. The secret to its success lies in its complex nanostructure — and how that structure changes as the egg incubates.

Chicken eggshells are about 95 percent calcium carbonate by mass. But they also contain hundreds of different kinds of proteins that influence how that calcium carbonate crystalizes. The interaction between the mineral crystals and the proteins yields an eggshell that’s initially crack-resistant, while making nanoscale adjustments over time that ultimately let a chick peck its way out, researchers report online March 30 in Science Advances.
Researchers used a beam of ions to cut thin cross sections in chicken eggshells. They then analyzed the shells with electron microscopy and other high-resolution imaging techniques. The team found that proteins disrupt the crystallization of calcium carbonate, so that what seems at low resolution to be neatly aligned crystals is actually a more fragmented jumble. This misalignment can make materials more resilient: Instead of spreading unimpeded, a crack must zig and zag through scrambled crystals.
Lab tests back up that finding: The researchers added a key shell-building protein called osteopontin to calcium carbonate to yield crystals like those seen in the eggshells. The presence of that protein makes calcium carbonate crystals form in a nanostructured pattern, rather than smooth and even crystal, study coauthor Marc McKee, a biomineralization researcher at McGill University in Montreal, and colleagues found.

The team also found structural variation on a minute scale throughout the eggshell, though it’s only about a third of a millimeter thick. Inner layers have less osteopontin, leading to bigger nanostructures. That may make the inner shell less resilient than the outer shell, which makes sense, McKee says­­. The outer shell needs to be hard enough to protect the chick, while the inner shell nourishes the developing chick.

Over time, the inner layers of the shell dissolve through a chemical reaction, releasing calcium to build a chick’s developing bones. The eggshell undergoes structural changes to facilitate that process, McKee and his colleagues found.

The researchers compared fertilized eggs incubated for 15 days to nonfertilized eggs. Over time, the nanostructures toward the inner shell became smaller in fertilized eggs, but remained the same in the nonfertilized eggs. The change gives the inside of the eggshell a bumpier texture, and by extension, more surface area. That provides more space for that shell-dissolving chemical reaction to take place, the researchers propose. The reaction also thins the shell overall, making it easier for a chick to break through from the inside when it’s time to hatch.

Advances in imaging technology are helping scientists find new details like this even in objects as familiar as a chicken eggshell, says Lara Estroff, a materials scientist at Cornell University who wasn’t part of the research. In connecting the eggshell’s functionality with its fine-grain structure, the new study could provide inspiration for designing new kinds of materials with specific properties.

Your brain might make new nerve cells well into old age.

Healthy people in their 70s have just as many young nerve cells, or neurons, in a memory-related part of the brain as do teenagers and young adults, researchers report in the April 5 Cell Stem Cell. The discovery suggests that the hippocampus keeps generating new neurons throughout a person’s life.

The finding contradicts a study published in March, which suggested that neurogenesis in the hippocampus stops in childhood (SN Online: 3/8/18). But the new research fits with a larger pile of evidence showing that adult human brains can, to some extent, make new neurons. While those studies indicate that the process tapers off over time, the new study proposes almost no decline at all.
Understanding how healthy brains change over time is important for researchers untangling the ways that conditions like depression, stress and memory loss affect older brains.

When it comes to studying neurogenesis in humans, “the devil is in the details,” says Jonas Frisén, a neuroscientist at the Karolinska Institute in Stockholm who was not involved in the new research. Small differences in methodology — such as the way brains are preserved or how neurons are counted — can have a big impact on the results, which could explain the conflicting findings. The new paper “is the most rigorous study yet,” he says.

Researchers studied hippocampi from the autopsied brains of 17 men and 11 women ranging in age from 14 to 79. In contrast to past studies that have often relied on donations from patients without a detailed medical history, the researchers knew that none of the donors had a history of psychiatric illness or chronic illness. And none of the brains tested positive for drugs or alcohol, says Maura Boldrini, a psychiatrist at Columbia University. Boldrini and her colleagues also had access to whole hippocampi, rather than just a few slices, allowing the team to make more accurate estimates of the number of neurons, she says.
To look for signs of neurogenesis, the researchers hunted for specific proteins produced by neurons at particular stages of development. Proteins such as GFAP and SOX2, for example, are made in abundance by stem cells that eventually turn into neurons, while newborn neurons make more of proteins such as Ki-67. In all of the brains, the researchers found evidence of newborn neurons in the dentate gyrus, the part of the hippocampus where neurons are born.

Although the number of neural stem cells was a bit lower in people in their 70s compared with people in their 20s, the older brains still had thousands of these cells. The number of young neurons in intermediate to advanced stages of development was the same across people of all ages.

Still, the healthy older brains did show some signs of decline. Researchers found less evidence for the formation of new blood vessels and fewer protein markers that signal neuroplasticity, or the brain’s ability to make new connections between neurons. But it’s too soon to say what these findings mean for brain function, Boldrini says. Studies on autopsied brains can look at structure but not activity.

Not all neuroscientists are convinced by the findings. “We don’t think that what they are identifying as young neurons actually are,” says Arturo Alvarez-Buylla of the University of California, San Francisco, who coauthored the recent paper that found no signs of neurogenesis in adult brains. In his study, some of the cells his team initially flagged as young neurons turned out to be mature cells upon further investigation.

But others say the new findings are sound. “They use very sophisticated methodology,” Frisén says, and control for factors that Alvarez-Buylla’s study didn’t, such as the type of preservative used on the brains.

Composting waste is heralded as being good for the environment. But it turns out that compost collected from homes and grocery stores is a previously unknown source of microplastic pollution, a new study April 4 in Science Advances reports.

This plastic gets spread over fields, where it may be eaten by worms and enter the food web, make its way into waterways or perhaps break down further and become airborne, says Christian Laforsch, an ecologist at the University of Bayreuth in Germany. Once the plastic is spread across fields, “we don’t know its fate,” he says.
That fate and the effects of plastic pollution on land and in freshwater has received little research attention compared with marine plastic pollution, says ecologist Chelsea Rochman of the University of Toronto. Ocean microplastics have gained notoriety thanks in part to coverage of the floating hulk of debris called the great Pacific garbage patch (SN Online: 3/22/18).

But current evidence suggests that plastic pollution is as prevalent in land and freshwater ecosystems as it is in the oceans, where it’s found “from the equator to the poles,” says Rochman, author of a separate commentary on the state of plastic pollution research published in the April 6 Science. Plastic “is seen in the high Arctic, where we suspect it comes down in rain. We know it’s in drinking water, in our seafood and spread on our agricultural fields,” she says.

Laforsch and his colleagues looked at several different kinds of biowaste that’s composted and spread on farmland in Germany, including household compost and grass clippings, supermarket waste and grain silage leftover from biogas production.

Compost samples taken from supermarket waste contained the greatest amount of plastic particles, with 895 pieces larger than 1 millimeter found per kilogram of dry weight. Household compost in contrast contained 20 and 24 particles per kg of dry weight, depending on the size of the sieves used to sift the compost. The detritus included bits of polyester and a lot of styrene-based polymers, commonly used in food packaging. Almost no particles were found in samples of silage from biogas production.
“I never thought about plastic in compost ending up as fertilizer. But when you think about it, it makes sense,” says environmental scientist Ad Ragas of Radboud University in Nijmegen, The Netherlands, who wasn’t involved in the work. A crate of rotting cucumbers wrapped in plastic that gets chucked, those stickers on every tomato in a bunch — that packaging doesn’t disappear.

Ragas says compost probably doesn’t contribute as much plastic to the environment as other sources, such as sewage treatment plant sludge, which contains polyester debris from clothes washers, and runoff from streets, which can be loaded with particles of synthetic rubber used in tires. But the compost contribution deserves investigation, Ragas says. “This triggers a lot of questions we haven’t studied yet.”

Those questions include possible effects on different organisms, from plants to earthworms to birds to people, Rochman says. Those effects will likely differ depending on the kind of plastic, which varies depending on its starting polymer and the additives used to impart certain qualities such as flexibility, sturdiness or durability under ultraviolet light.

“We are not saying we should get rid of all plastics,” Rochman says. “But we do need to start thinking of plastics as a persistent global pollutant.”

A hellishly unprecedented scene — what anthropologists suspect is the largest known child sacrifice — has been unearthed on a bluff overlooking Peru’s northern shoreline.

Around 550 years ago, members of the Chimú empire ritually killed and buried at least 140 children, ages 5 to 14, and 200 young llamas, says a team led by Gabriel Prieto of the National University of Trujillo in Peru and John Verano of Tulane University in New Orleans.

“There are no other examples of child sacrifices anywhere in the world that compare to the magnitude of this Chimú event,” Verano says. The discovery was announced April 26 by National Geographic in Washington, D.C.
Except for a few incomplete skeletons, excavated children and llamas displayed cuts on their breast bones and dislocated ribs indicating that their chests had been sliced open. Three adults buried nearby on the bluff, including two women with violent head wounds, may have participated in the sacrifice.

Radiocarbon dating, mainly of ropes left around the llamas’ necks, puts the event at around 1450, shortly before the Inca conquered the Chimú in 1470.

A dried mud layer covering some of the sandy graves possibly resulted from flooding caused by massive rains. Agricultural crises triggered by repeated flooding might have led Chimú leaders to sacrifice children to their gods, Verano suggests.

For some neutron stars, the quickest way to cool off isn’t with a frosty beverage, but with lightweight, subatomic particles called neutrinos.

Scientists have spotted the first solid evidence that some neutron stars, the collapsed remnants of exploded stars, can rapidly cool their cores by emitting neutrinos. The result adds to evidence that scientists are gathering to understand the ultradense matter that is squished deep within a neutron star’s center.

The new evidence comes from a neutron star that repeatedly gobbled material from a neighboring star. The neutron star rapidly cooled off after its meals, scientists determined. X-rays emitted by the neutron star showed that the fast cooldown rate was consistent with a theorized effect called the direct Urca process, in which neutrinos quickly ferry energy away from a collapsed star, astrophysicist Edward Brown and colleagues report in the May 4 Physical Review Letters.
Neutron stars are known to emit neutrinos by a similar process that cools the star slowly. But previously, there wasn’t clear evidence for faster cooling. The team analyzed observations of the neutron star, located about 35,000 light-years from Earth, as it cooled during a 15-year interlude between feeding sessions. Neutrinos carried away energy about 10 times faster than the rate energy is radiated by the sun’s light — or about 100 million times quicker than the slow process, says Brown, of Michigan State University in East Lansing.

Although some other neutron stars have shown hints of such a quick chill, “this is basically the first object for which we can see the star actively cooling before our eyes,” says astrophysicist James Lattimer of Stony Brook University in New York, who was not involved with the research.

The direct Urca process, named by physicists George Gamow and Mário Schenberg in the 1940s, took its moniker from the now-defunct Urca casino in Rio de Janeiro. “The joke being that this process removes heat from the star the way the casino removes money from tourists’ pockets,” Brown says.
In the process, neutrons in the star’s core convert into protons and emit electrons and antineutrinos (the antimatter partners of neutrinos). Likewise, protons convert into neutrons and emit antielectrons and neutrinos. Because neutrinos and antineutrinos interact very rarely with matter, they can escape the core, taking energy with them. “The neutrino is a thief; it robs energy from the star,” says physicist Madappa Prakash of Ohio University in Athens, who was not involved with the research.

The observation may help scientists understand what goes on deep within neutron stars, the cores of which are squeezed to densities far beyond those achievable in laboratories. Although the simplest theory holds that the cores are crammed with neutrons and a smaller number of protons and electrons, scientists have also proposed that the collapsed stars may consist of weird states of matter, containing rare particles called hyperons or a sea of free-floating quarks, the particles that make up protons and neutrons (SN: 12/23/17, p. 7).

The direct Urca process can happen only if the fraction of protons in the center of the neutron star is larger than about 10 percent. So if the process happens, “that already tells us a lot,” says astrophysicist Wynn Ho of Haverford College in Pennsylvania, who was not involved in the research. Such observations could eliminate theories that would predict lower numbers of protons.

However, the scientists weren’t able to determine the mass of the neutron star, limiting the conclusions that can be drawn. But, says Prakash, if the mass of such a quickly cooling neutron star is measured, the neutron star’s interior makeup could be nailed down.

Far from their usual tropical waters, some 200 bottlenose dolphins and about 70 false killer whales have been spotted off the western coast of Canada’s Vancouver Island. Over on the Atlantic coast, bull sharks have turned a North Carolina estuary into a nursery — a sight more familiar in Florida, until now.

Two new studies highlight the unusual northern sightings of these three ocean predators.“Alone, these sightings could be seen as accidental, or vagrancies,” says marine ecologist Luke Halpin of Halpin Wildlife Research in Vancouver and part of the team tracking the dolphins sighting. “But we’re seeing a lot of warm-water species ranging into historically cold North Pacific waters.” Those include dwarf sperm whales (Kogia sima), pygmy sperm whales (Kogia breviceps) and short-finned pilot whales (Globicephala macrorhynchus) documented by other researchers.
The results suggest that these marine species will increasingly migrate outside of their typical range as climate change increases ocean temperatures, researchers say. In just the last century, average sea temperatures have risen every decade by 0.07 degrees Celsius, though temperature changes can vary widely by location.

The eastern North Pacific Ocean had experienced a three-year period of warming from 2013 to 2016, and by July 2017, water temperatures about 180 kilometers offshore of Vancouver Island hit 16.5° C. That’s smack in the middle of the range that common bottlenose dolphins (Tursiops truncatus) prefer and at the low end for false killer whales (Pseudorca crassidens).

Typically, bottlenose dolphins aren’t found in offshore waters above Eureka, Calif., and false killer whales don’t venture north of Pismo Beach, Calif. But during a routine seabird and marine mammal survey, Halpin spotted a large herd of the marine mammals off the boat’s stern. He watched for 40 minutes as the dolphins and false killer whales leaped through the water and paused to spyhop, popping their heads up vertically out of the water. At one point, some came within 400 meters of the boat. It was the first time either species had been seen in noncoastal waters of the Canadian Pacific, the researchers report online April 20 in Marine Biodiversity Records.

A similar trend is being seen in the Atlantic Ocean, with baby bull sharks appearing in increasing numbers every year since 2011 in Pamlico Sound in North Carolina, another research team reports online April 16 in Scientific Reports. Previously, the northernmost nursery for bull sharks (Carcharhinus leucas) had been Florida’s Indian River Lagoon.
But since 2008, water temperatures in early summer, when bull sharks give birth to live young, have exceeded 25° Celsius more than 60 percent of the time in the North Carolina estuary. Salinity also has slowly increased in the sound over the last few decades, from a range of 4.5 to 18.3 parts per thousand in 1971 to 9 to 17.4 parts per thousand since 2011. Young bull sharks are found only in salinities higher than 9 parts per thousand.

Changing conditions in the sound have created “the comfort zone that bull sharks will reproduce in,” says marine ecologist Charles Bangley of the Smithsonian Environmental Research Center in Edgewater, Md., lead author on the shark study.

Migration by these three top-level ocean predators could have consequences for predator-prey relationships, says marine ecologist Rebecca Selden at Rutgers University in New Brunswick, N.J., who was not involved in either of the studies. Dolphins and sharks eat a wide range of prey, so as they move into new areas, prey species there may encounter these larger predators for the first time. That could impact populations of prey species, which in turn could “cause some big ecosystem effects,” she says.

What do land mines and tuberculosis have in common? Both kill people in developing countries — and both can be sniffed out by rodents that grow up to 3 feet, head to tail.

Since 2000, the international nonprofit APOPO has partnered with Tanzania’s Sokoine University of Agriculture to train African giant pouched rats (Cricetomys ansorgei) to pick up the scent of TNT in land mines. By 2016, the animals had located almost 20,000 land mines in Africa and Southeast Asia.
To help more people, Georgies Mgode, a zoonotic disease scientist at Sokoine, and colleagues began training the rats to recognize tuberculosis, an infectious disease that killed about 1.6 million people in 2016. The most common diagnostic tool — inspection of patients’ sputum under a microscope — can miss infections more than half the time. More accurate technologies are costly or still in testing (SN Online: 2/28/18).
“Every disease, anything organic, has a smell,” says Mgode. Mycobacterium tuberculosis
, the bacterium that causes TB, emits 13 volatile chemicals that set it apart from other microbes, he and colleagues reported in 2012. Training a rat to be a TB sniffer, recognizing those smells in phlegm, takes about nine months.
To start, trainers bond with 4-week-old rats, naming the pups, playing with them and hand-feeding them. During training, the rats get a food reward when they pause at infected samples. Most trained rats can work through 100 samples in less than 20 minutes, faster than other methods, Mgode says.

Still, convincing others to accept the rats as a diagnostic tool has been a challenge. On April 4 in Pediatric Research, Mgode and colleagues made their latest pitch, based on over 55,000 sputum samples from Tanzanian clinics examined by trained rats between 2011 and 2015. Microscopy detected TB in 8,351 samples. The rats detected those, plus 2,745 more, later verified by standard methods. The animals did especially well on samples from young kids, who often cough up less phlegm for testing and have low bacterial counts.

Today, as part of the continuing research project, the rats screen TB samples from Tanzania and Mozambique, and soon Ethiopia. But the rats have yet to receive global approval from the World Health Organization.

“We are working very hard according to good lab practices, we have well-documented protocols and we are abiding by endorsed techniques,” Mgode says. “People [with TB infection] who are being missed in the hospitals are being confirmed by the rats.”

Editor’s note: This article was updated on May 16, 2018, to clarify that the TB-sniffing rat program is an ongoing research project.

Psychologists generally regard preschoolers as supreme copycats. Those little bundles of energy will imitate whatever an adult does to remove a prize from a box, including irrelevant and just plain silly stuff. If an experimenter pats a container twice before lifting a latch to open it, so will most kids who watched the demonstration.

There’s an official scientific name for mega-mimicry of this sort: overimitation. Maybe copying everything helps youngsters learn rituals and other cultural quirks. Maybe kids imitate to excess so that an adult who appears to possess special knowledge will like them.
Or maybe overimitation is overrated. In realistic learning situations — where children can gauge whether a majority of adults are patting a box or otherwise going off course before getting down to business — copycat fever cools off dramatically.

That’s the conclusion of a team led by psychologist Cara Evans of the Max Planck Institute for the Science of Human History in Jena, Germany. “The term ‘overimitation’ misleadingly suggests that children mindlessly and inefficiently copy irrelevant actions,” Evans says. “Instead, children imitate adults in highly flexible, selective and adaptive ways.”

The researchers tested 252 British children, ages 4 to 6, who were visiting science centers with their parents. Of those, 201 kids watched a video showing four adults consecutively demonstrate how to remove a capsule containing a sticker from a clear plastic box. Either all, 3 of 4, 1 of 4, or none of the demonstrators performed an irrelevant action — sliding open a small door in the box to reveal an empty space — before using one of two levers to move the capsule in front of the door. The other 51 kids saw no demonstrations.

Each child then had a chance to get a sticker, previously chosen as his or her favorite, out of the box. Those who succeeded got two more tries at extracting new stickers.
In line with past overimitation studies, nearly all kids who saw all four adults demonstrate the superfluous door-opening routine copied that behavior on all trials. But only about 40 percent of those who saw three of four adults open the door to nowhere did the same on their first try. That percentage dropped by nearly half on second and third go-rounds with the box. All it took was one adult demonstrating a better prize-releasing technique to elicit that behavior in kids. The results will be published later this year in Developmental Science.

As with children who saw no demonstrations, the kids who saw the irrelevant door-opening performed by only one adult rarely imitated the action.

In short, preschoolers did not blindly follow the crowd, Evans says. If only one out of four adults showed how to extract a prize efficiently, then the kids were alright with that and copied the outlier. Evans suspects that children copied unanimous demonstrations of a useless procedure because they figured “this is the way it is done,” even if the extra step seemed unnecessary.

Evans sees a connection between her findings and the results of social psychologist Solomon Asch’s famous conformity experiments from the 1950s. Ash observed that individual college students went along with groups of peers who, in league with Asch, unanimously said that lines of different lengths were actually the same length. But volunteers resisted peer pressure if just one other person, at Asch’s direction, dissented from the crowd.

When it comes to deciding whom to imitate and whom to ignore, kids and adults can be equally discriminating.

KOCHI, India — The rare and deadly Nipah virus has emerged in southern India, killing at least 11 people and causing more than 25 others to be hospitalized. Although global health officials consider that, so far, to be a relatively small outbreak, they’re worried.

Nipah is on the World Health Organization’s priority list of emerging diseases that could cause a global pandemic, alongside Zika and Ebola.

“This is the first time we’ve seen the virus in south India,” says R.L. Sarita, the director of health services in the Indian state of Kerala. “And we want to make sure that it stays contained here.”
Those infected suffer a quick onset of symptoms, including fever, vomiting, disorientation, mental confusion, encephalitis and — in up to 70 percent of cases, depending on the strain — ultimately death. Here’s what we know, and don’t know, about this incurable disease:

How is the Nipah virus spread?
Several species of fruit bat that live throughout Asia carry Nipah. During outbreaks in Bangladesh from 2001 to 2007, most people contracted the virus by drinking raw date palm sap that virus-carrying fruit bats had also sipped and contaminated (SN: 12/19/09, p. 15).
Bats can also transmit Nipah to pigs and other livestock, which can then pass the infection onto humans. And humans can spread the virus through saliva and possibly other bodily fluids. One victim in the latest outbreak was a 31-year-old nurse who had been treating Nipah patients.

To find the source of this outbreak, health officials in India are testing local bats, livestock and food samples, including mangos that may have been bitten by bats, found in the home of a family that lost four members to Nipah.
How does the virus cause infection?
Nipah and its viral cousin Hendra latch onto a proteins called ephrin-B2 and ephrin-B3 on the surface of nerve cells and the endothelial cells lining blood and lymph vessels, researchers have found. Nipah can also invade lung and kidney cells.

Virologists who have studied Nipah’s behavior in animals think that in humans, it initially targets the respiratory system before spreading to the nervous system and brain. Most patients who die succumb to an inflammation of blood vessels and a swelling of the brain that occurs in the later stages of the disease.

Why are epidemiologists worried about Nipah?
“The No. 1 reason is that it’s just so lethal,” says Linfa Wang, who heads the emerging infectious diseases program at the Duke-NUS Medical School in Singapore. In fact, the villain virus in the 2011 film Contagion was based on Nipah (SN Online: 10/19/11).

Since the virus was first documented in 1998, there have been small, contained outbreaks almost every year in southeast Asia and Bangladesh.

But Nipah has the potential to spread farther — due to the fact that its fruit bat carriers live across a wide range extending from Australia to West Africa.

In addition, some strains are more lethal than others. An outbreak in Malaysia in 1999 was caused by a strain with a 30 percent mortality rate, while the Bangladesh outbreaks involved a different strain that killed 70 percent of infected humans. Scientists aren’t sure why the mortality rates are so different.

Is Nipah the next Ebola?
Not quite, says Stanford University epidemiologist Stephen Luby, who has studied the disease in Bangladesh, where there have been either outbreaks or sporadic cases almost every year since 2001. The two known Nipah strains currently circulating aren’t all that easy to transmit.
While the mortality rate for those infected can be high, infection is not all that common. Before this latest outbreak, about 300 deaths had been linked to Nipah, most of which occurred in Southeast Asia and Bangladesh. But the actual number could be higher, Luby says, with some cases going untested or unreported. Because the symptoms of Nipah infection are similar to those for other diseases, including encephalitis and the flu, cases may be misdiagnosed. India has only two main diagnostic laboratories, both in the central city of Pune, equipped to confirm Nipah infection.
“In order for a disease to spread globally, each person has to infect at least more than one person,” Luby says. But a person with Nipah tends to infect either zero or one other person, according to a 2009 study published online by the U.S. Centers for Disease Control and Prevention. By comparison, a person with measles can infect on average 10 others who aren’t vaccinated. And people who caught Ebola during the 2014 outbreak in West Africa tended to pass it on to between one and three others, PLOS Current Outbreaks reported in 2014.

But “anytime the virus is inside a human, it has the opportunity to evolve and adapt to that human-specific environment,” Luby says. The worst-case scenario is a future strain that can transmit more quickly or easily among humans, which is why the WHO and global health experts are urging more research into vaccines and treatments.

“I hope what we learned from the Ebola outbreak, is that if we have the ability to prepare, we should do that,” says Emily Gurley, an infectious disease epidemiologist at the Johns Hopkins Bloomberg School of Public Health in Baltimore

In fact, in response to this latest outbreak, the Coalition for Epidemic Preparedness Innovations (CEPI), a global alliance that formed last year to encourage and finance the development of vaccines, has announced that they will be granting $25 million to two American biotech companies to accelerate work on a Nipah vaccine. Researchers have tested experimental Nipah vaccines on animals, but have yet to conduct clinical trials.

Are fruit bats the problem?
Having been around for millions of years, bats have probably carried infectious diseases for nearly as long, Gurley says. Several bat species can carry viruses that are deadly to humans, including Ebola, Marburg, SARS and Nipah, without getting sick themselves (SN: 3/9/13, p. 10).

But scientists say that villainizing bats is not the answer. “They’re a crucial part of their ecosystems,” Gurley says. “They are also really important pollinators.”

Several factors have increased the chance of bat-borne viruses being passed humans, including development that has encroached on the bats’ natural habitats. “It used to be that these bats stayed far away from human populations,” Wang says.

Don’t count on a shady parking spot to save a child left in the back seat on a hot day.

A new analysis of temperatures inside parked cars reveals that a toddler in a sunbathed vehicle would reach lethal body temperatures faster than one left in the shade. But even in a shaded car, a child could die from overheating within a few hours, researchers report online May 23 in Temperature.

Researchers tracked temps inside three cars — a sedan, economy car and minivan — that were parked in the sun, and another three parked in the shade. Each car started at the outdoor air temperature or 29.4° Celsius, whichever was cooler. On days hotter than 38° C (about 100° Fahrenheit), it took an hour for the average ambient temperature inside the shaded vehicles to reach 38.3° C. For cars in the sun, the inside temperature hit a scorching 46.7° C in an hour, with surfaces such as steering wheels, dashboards and seat covers getting even hotter.
The researchers then simulated how the body temperature of a 2-year-old would increase under those conditions. On average, a toddler’s body would reach the potentially lethal temperature of 40° C (104° F) after about 1.4 hours in the sun and about 2.4 hours in the shade. It happened faster in some cars than others — a child left in a sunbaked sedan could die from overheating in just an hour.

On average, 37 children in the United States die from heatstroke inside vehicles each year, and in more than half of those cases, the children had simply been forgotten. Car or smartphone alerts reminding drivers to check the back seat could help prevent these deaths, says coauthor Jennifer Vanos, an extreme heat and public health researcher at the University of California, San Diego.