A newly discovered species of tomato belongs in a haunted house, not on a sandwich.

Fruit from the bush tomato plant Solanum ossicruentum bears little resemblance to its cultivated cousins. The Australian tomato, about a couple centimeters wide, grows enclosed in a shell of spikes. These burrs probably help the fruit latch on to the fur of passing mammals, which then spread the tomato’s seeds elsewhere, researchers at Bucknell University in Lewisburg, Pa., report May 3 in PhytoKeys.

Slice open the fearsome fruit and within five minutes, its sticky white-green flesh appears to bleed, flushing bright red to dark maroon in response to air exposure. One brave researcher tasted an unripe fruit and deemed it salty. The bush tomato becomes no more appetizing with time: Mature fruits harden into dry, bony nuggets.

The tomato’s gruesome qualities inspired its name, courtesy of a group of Pennsylvanian seventh-grade science students: “Ossicruentum” combines the Latin words for “bone” and “bloody.”

Social media supporters of the Islamic State, or ISIS, form online groups that may provide clues crucial to predicting when terrorist attacks will take place, a new analysis finds.

These virtual communities drive ISIS activity on a Facebook-like site called VKontakte, say physicist Neil Johnson of the University of Miami in Coral Gables, Fla., and colleagues. VKontakte, a social networking service based in Russia with more than 350 million users, allows messaging in many languages and is used worldwide.
In the June 17 Science, Johnson’s team describes a mathematical model that predicts online groups of ISIS supporters will proliferate days before real-world Islamic State attacks. That’s just what happened in September 2014, researchers say. Pro-ISIS groups on VKontakte mushroomed the day before Islamic State forces overran Kobane, a small Syrian town.

The researchers refer to groups of followers of an online page that form spontaneously as aggregates. “Our work suggests that, to manage and monitor online ISIS activity, we need to focus on aggregates rather than individuals,” Johnson says.

Pro-ISIS aggregates on VKontakte exchanged information on issues such as recruiting fighters to Syria and how to survive drone attacks.

The new model suggests that authorities need to shut down online pro-ISIS groups in their early stages. Small-scale aggregates favoring the same cause gradually expand when left alone and eventually merge into a much larger online community that’s more difficult to break up, Johnson’s model forecasts.

“This is the first serious, large-scale, data-driven study that shows how online support develops for terrorist groups such as ISIS,” says computer scientist V.S. Subrahmanian of the University of Maryland in College Park, who builds computational models of terror networks. But it remains to be seen whether the new model can predict when and possibly where future Islamic State attacks will occur, Subrahmanian cautions.
Johnson’s team identified 196 pro-ISIS aggregates, consisting of 108,086 individual followers, which operated between January 1 and August 31, 2015. Intelligence agencies, hackers and website moderators work to shut down these online groups, but to a lesser extent on VKontakte than on Facebook.

Pro-ISIS aggregates rapidly adapted to these survival threats in several ways, the researchers say. Fifteen percent of aggregates changed their online names; 7 percent flipped back and forth between opening their content to any VKontakte user or to current aggregate followers only; and 4 percent engaged in a digital form of reincarnation. Pro-ISIS aggregates under unusually intense attack by hackers and others opted for reincarnation, Johnson says.

Reincarnating aggregates disappeared and then returned, often within weeks, with new names and at least 60 percent of the same followers as before. Aggregates that vanished appear to have reassembled without any direction or urging from one or a few members, Johnson says. New names of reincarnated groups often resembled original names enough to alert former members but not enough to trigger VKontakte’s automated system for identifying names of probable pro-militant groups, he points out.

As with predictions of terror attacks based on the expansion of pro-ISIS aggregates, the new model shows promise in predicting when mass public protests will occur based on sudden jumps in numbers of pro-protest aggregates, the scientists say. There is a difference: Reincarnation did not appear within the last three years among Facebook aggregates consisting of civil protesters in Brazil and several other Latin American countries, the researchers found. Those online groups experienced fewer pressures to shut down than pro-ISIS aggregates on VKontakte did.

Johnson’s analysis moves the study of online militant groups forward, says terrorism analyst J.M. Berger of George Washington University in Washington, D.C. But it’s likely that considerably fewer members of pro-ISIS aggregates than the total studied in the new analysis were actually hard-core Islamic State supporters, Berger contends. Concerted efforts to shut down online terrorist networks have depressed numbers of committed ISIS supporters using social media, in his view. Berger and a colleague have found that English-language Twitter use has declined sharply among ISIS supporters over the last two years, due to suspensions of their accounts by the social media site.

Johnson suspects most pro-ISIS aggregate members were staunch supporters, since aggregates aggressively weed out those deemed unserious or hostile.

Terrorists use chains of social and messaging sites online to achieve their ends, Subrahmanian says. How that works, and whether the same aggregate operates under different guises from one site to the next, has yet to be studied.

Scientists have found a new way to study how cancer cells divide and thrive in difficult-to-reach crannies of the body.

Transparent artificial membranes — just nanometers thick — can be rolled into tubes to mimic capillaries that host spreading cancer cells, researchers report in the June ACS Nano. Cells squished inside such tubes didn’t organize their internal components the way they normally do before splitting. As a result, the cells divided unevenly, potentially introducing new mutations.
Inside the body, cancer cells fight for space. Sometimes they’ll spread, or metastasize, to other organs via tight blood vessels. Although cancer cells are more likely to kill once they spread, scientists still don’t understand how the abnormal cells divide inside such tiny tubes. These cells are difficult to study in the body because they’re tucked away in hard-to-reach places. They’re challenging to study in the lab, too, because they behave differently in a petri dish than in their natural environment.

By replicating that environment more closely, this experiment gives “an appreciation for what it’s like to be a cell in a body,” says Buzz Baum, a biologist at University College London who was not involved in the work.

Other researchers have looked at cells constrained in other ways. But the nanotubes are round, just like blood vessels. They’re transparent, making it easier to visualize what’s happening inside. And it’s possible to study many cells at once by growing nearly a thousand tubes, all exactly the same size, on a chip slightly larger than a postage stamp.

When watching single human cancer cells inside the tubes through high-powered microscopes, the team noticed that the squished cells didn’t divide symmetrically. Instead of sending half the chromosomes to each new cell, some of those cells got extra genetic instructions, while others were shortchanged.

The squished cells also took longer to divide. And the protein structures that help guide the chromosomes and organelles into place before division didn’t develop correctly, says study coauthor Wang Xi, a materials scientist who did the work at the Leibniz Institute for Solid State and Materials Research Dresden in Germany.
Cancer cells succeed by mutating enough that they can evade capture, without becoming too mutated to keep replicating.

“A cell that makes too many mistakes will just die,” says Baum.

When cells are trapped inside blood vessels, “they become misshapen but they’re still able to divide,” says Xi, now at the National University of Singapore.

Xi and his colleagues think that a bulging of the cell membrane in response to pressure, called blebbing, might help the trapped cells divide in a slightly less distorted way. When the researchers prevented the cells from blebbing, the division was even more uneven. But because the team can’t yet explain why this would be the case, it’s too soon to say whether blebbing itself is responsible for the improved division.

Baum says he has shown similar deformities in cancer cells dividing under other types of constraints. But, he adds, it’s important to have systems that more closely replicate the body’s internal environment. Otherwise, it can be a big jump between doing tests in a petri dish and in a live animal.

Study coauthor Christine Schmidt, a biochemist at the University of Cambridge, says understanding how cancer cells manage to divide in tight quarters could eventually inspire ways to kill spreading cancer cells without hurting healthy cells.

Knuckleballs baffle baseball players with their unpredictable swerves. A new study suggests a possible cause of the pitch’s erratic flight — sudden changes in the drag force on a ball, due to a phenomenon called a drag crisis.

The result is at odds with previous research that attributed the zigzags to the effect of airflow over the baseball’s seams. Scientists report the finding July 13 in the New Journal of Physics.

Knuckleballs are well known in baseball, but similar phenomena also confound players in soccer and volleyball. Knuckleballs occur when balls sail through the air with very little spin, producing unstable flight.
In drag crisis, the thin layer of air surrounding the ball flips between turbulent and smooth flow, abruptly changing the drag forces on the ball. If the transition occurs asymmetrically, it can push the ball to one side. “This phenomenon is intermittent” and hard to predict, says study coauthor Caroline Cohen, a physicist at École Polytechnique in Palaiseau, France. “We can’t know in advance [to] which side it will go.” Balls must move at a certain speed to experience a drag crisis, which may be why knuckleballs tend to be thrown slower than other pitches, the researchers suggest. While the fastest pitches can top 100 miles per hour, knuckleballs are usually closer to 60 or 70 miles per hour.

The scientists built a knuckleball machine, designed to launch a beach ball without any spin, and measured how much the ball veered off course. Then they calculated the ball’s expected motion based on the physics of the drag crisis and found that the predicted trajectories matched the experiments. The scientists’ calculations also correctly predict knuckleball-like phenomena in soccer, volleyball, cricket and baseball — but not in sports like tennis or basketball, where knuckleballs aren’t seen due to the properties of the ball, including texture, typical speed and how far it flies.

“It’s a fine piece of work,” says Alan Nathan of the University of Illinois at Urbana-Champaign, who studies the physics of baseball (SN: 3/23/13, p.32). But he is not entirely convinced by the explanation of knuckleballs. “Wind tunnel experiments seem to strongly suggest that it’s associated with the seams on the ball,” Nathan says, which can create turbulence that causes the ball to swerve.

So knuckleballs may remain as much of a challenge to explain as it is to hit them.

A roughly 27-million-year-old fossilized skull echoes growing evidence that ancient whales could navigate using high-frequency sound.

Discovered over a decade ago in a drainage ditch by an amateur fossil hunter on the South Carolina coast, the skull belongs to an early toothed whale. The fossil is so well-preserved that it includes rare inner ear bones similar to those found in modern whales and dolphins. Inspired by the Latin for “echo hunter,” scientists have now named the ancient whale Echovenator sandersi.
“It suggests that the earliest toothed whales could hear high-frequency sounds,” which is essential for echolocation, says Morgan Churchill, an anatomist at the New York Institute of Technology in Old Westbury. Churchill and his colleagues describe the specimen online August 4 in Current Biology.

Modern whales are divided on the sound spectrum. Toothed whales, such as orcas and porpoises, use high-frequency clicking sounds to sense predators and prey.

Filter-feeding baleen whales, on the other hand, use low-frequency sound for long-distance communication. Around 35 million years ago, the two groups split, and E. sandersi emerged soon after.

CT scans show that E. sandersi had a few features indicative of ultrasonic hearing in modern whales and dolphins. Most importantly, it had a spiraling inner ear bone with wide curves and a long bony support structure, both of which allow a greater sensitivity to higher-frequency sound. A small nerve canal probably transmitted sound signals to the brain.
“Scientists have long suspected that early toothed whales could produce the high-frequency sounds needed for echolocation based on features on their skulls,” says Travis Park of Monash University in Melbourne, Australia. Previous work points to early toothed whales sensing those high frequencies. Park and his colleagues reported in April in Biology Letters the discovery of a 26-million-year-old lone ear bone showing signs of high-frequency hearing. But it wasn’t connected to a skull and, thus, couldn’t be tied to a specific whale species.

Tracing inner ear features in CT scans of 24 ancient and modern whales, including E. sandersi, plus two hippos, whales’ closest living relatives, Churchill’s team ups the ante. Because primitive versions of the bony spiral and nerve canal appeared before the first known toothed whale, the researchers suggest that rudimentary high-frequency hearing might have emerged in the common ancestor of toothed and baleen whales at least 43 million years ago. If so, baleen whales lost their high-frequency hearing at some point. Determining whether that’s truly the case requires more analysis and a wider array of fossil data, says Park, who’s unconvinced.

But there is growing consensus that the first toothed whales could hear and produce sounds at high-frequency ranges. The skull of a 28-million-year-old toothed whale also suggests that such animals could make high-frequency calls (SN: 4/19/14, p. 6). “The next step is to look at when their brains got big enough to process echolocation signals,” says Nicholas Pyenson, a paleobiologist at the Smithsonian’s National Museum of Natural History who was not affiliated with the study. “This is great, but there’s more to be done.”

Capybaras, giant rodents native to South America, could become Florida’s next big invasive species, a biologist warned August 3 in Columbia, Mo., at the 53rd Annual Conference of the Animal Behavior Society.

“Capybaras have been introduced to northern Florida,” said Elizabeth Congdon of Bethune-Cookman University in Daytona Beach, Fla. And there are enough similarities to nutria — large invasive rodents that have caused havoc in many states — to warrant a closer look at the South American newcomers.

There are currently about 50 capybara loose in northern Florida. Now, that may not seem like an invasion, and it’s not — yet. But these animals are the world’s largest rodent, growing to 50 kilograms or more. In the wild, the semiaquatic animals live in social groups in forests where they can be near bodies of water, such as rivers, lakes or swamps. They are herbivores that can subsist on a wide variety of vegetation, from grass to tree bark. And they reproduce at a fair pace, producing an average of four, and up to eight, pups per litter.

Most people wouldn’t look at those characteristics and think “I want to own one of those animals,” but some have. Capybaras are one of the many exotic creatures that people have tried to turn into pets. (Owning one is legal in some states.) But the animals can get loose, or people may purposely release them when they no longer want to own a giant rodent.

A capybara (or 50) loose in the countryside or city is not automatically an invasive species. The difference between an invasive and a nonnative exotic is whether an organism is causing environmental or economic harm, or harm to human health.

Congdon and her undergraduate students have been studying the potential for capybaras to make that transition from exotic to invasive, and they have been looking for similarities to nutria. Those large rodents were first imported to the United States in the early 1900s; the animals were farmed for their fur in Louisiana. But they escaped — some were also purposely released as weed mitigators — and quickly established themselves in Louisiana’s many swamps. Efforts to control the animals, such as hunting, have largely failed.

Nutria, which are smaller than capybaras, reproduce at about the same rate as the giant rodents. But one of the things that have made nutria such a menace — their propensity to dig into riverbanks, levees and other places that can cause problems when the ground disintegrates — appears to be a trait they don’t share with capybaras.
While coyotes and dogs are know to hunt nutria, it appears that nothing in the United States, other than a human, is big enough to kill a capybara. No animals here are equivalent to the capybara’s natural South American predators, which include anacondas, puma and jaguar, Congdon noted.

The state of Florida says only that a breeding population of capybaras “may exist,” but Congdon is pretty sure that there is one. In 1995, five animals escaped from a wildlife facility near Gainesville, and they are probably at least part of the source of those 50 capybaras now living in Florida. “Several sightings suggest they have been breeding,” Congdon said, including the finding of a juvenile capybara. Given the similarities to the nutria, and the ability of capybaras to adapt to a variety of habitats, including cities, “they might be able to make a go of it in the United States,” Congdon concluded.

But Congdon isn’t advocating that wildlife managers kill all the capybaras in Florida. The animals represent “an opportunity to study the process of invasion,” she said. Plus, a population in Florida would be a lot easier for her to access than the one she studied in Venezuela as a gradate student. “We want to keep them from spreading,” she said, “but can we please not kill them all so I can study them?”

Ötzi had Copper Age style.

The 5,300-year-old Tyrolean Iceman, whose body was found poking out of a glacier in the Italian Alps in 1991, incorporated hides from at least five domesticated and wild animal species into his apparel, a new genetic study finds. Comparing mitochondrial DNA extracted from nine ancient leather fragments with DNA of living animals revealed the makeup of Ötzi’s clothes and a key accessory, says a team led by paleogeneticist Niall O’Sullivan. Mitochondrial DNA typically gets passed from mothers to their offspring.
Little is known about what people wore during Ötzi’s time. The findings provide a glimpse into how ancient European populations exploited domesticated animals to make clothes and other items.

Ötzi’s coat consisted of hides from at least three goats and one sheep, the scientists report August 18 in Scientific Reports. This garment may have been periodically patched with leather from whatever animals were available, the team suggests.

Goats also provided skin for the Iceman’s leggings, the new analysis indicates.

A sheepskin loincloth and a shoelace derived from European cattle round out Ötzi’s attire made from domesticated animals.

As for wild animals, Ötzi wore a brown-bear cap and toted a quiver made from roe deer. It’s impossible to know if the ancient man attached any special meaning to brown bears, “but he may have been an opportunistic hunter or a scavenger,” says O’Sullivan, of University College Dublin and EURAC Research in Bolzano, Italy.
A 2012 analysis of proteins from fur samples taken from Ötzi’s clothing identified sheep and a goatlike animal called a chamois as sources for the Iceman’s coat. A team led by biochemist Klaus Hollemeyer of Saarland University in Saarbrücken, Germany, also pegged goats and dogs or wolves as sources of skin for Ötzi’s leggings.

Disparities between Hollemeyer’s and O’Sullivan’s studies may stem from the two groups having sampled different parts of patchwork garments. In addition, the new report used advanced techniques for extracting and analyzing ancient DNA. That enabled O’Sullivan’s team to retrieve six complete mitochondrial genomes from Ötzi’s leather belongings.

O’Sullivan’s investigation “opens a new field of potential identification procedures for mammalian species in ancient leathers and furs,” Hollemeyer says.

A roughly 4,200-year-old legging found in the Swiss Alps in 2004 also features goat hide. Mitochondrial DNA extracted from that garment came from an ancient line of European goats that has largely been replaced by a genetically distinct goat population, a team led by archaeologist Angela Schlumbaum of the University of Basel in Switzerland reported in 2010.

The Swiss legging was found with pieces of bows and arrows, woolen clothes and many other artifacts where an ice patch in a mountain pass had partly melted. No human bodies have been found there.

“Possibly, goat leather was most comfortable” as legging material, says University of Bern archaeologist Albert Hafner, a coauthor of the Swiss legging study. “Modern leather trousers often use goat as well.”

White, fierce and fluffy, snowy owls are icons of Arctic life. But some of these owls are not cool with polar winters.

Every year, part of the population flies south to North American prairies. Ornithologists thought those birds fled the Arctic in desperation, haggard and hungry. But the prairie owls are doing just fine, researchers report August 31 in The Auk: Ornithological Advances.

Over 18 winters, wild snowy owls caught and banded in Saskatchewan, Canada — one of the species’ southerly destinations­­ — were 73 percent heavier than emaciated owls in rescue shelters. Females were heavier and had more fat than males, and adults were in better condition than youngsters. But regardless of age or sex, most snowy owls that made the journey south were in relatively good health.

That means southern winters may not be such a desperate move after all. Prairies are probably just a normal wintering ground for some of the Arctic snowy owl population, the researchers say. Snowbirds, indeed.

Philae has been found, nestled in a shadowy crevice on comet 67P/Churyumov-Gerasimenko. The comet lander, lost since its tumultuous touchdown on the comet on November 12, 2014, turned up in images taken by the Rosetta orbiter on September 2.

Philae is on its side with one leg sticking out into sunlight. Its cockeyed posture probably made it difficult for Philae to reliably get in touch with Rosetta, explaining why scientists had trouble reestablishing communication. The discovery came about a month before the end of the Rosetta mission; the orbiter was scheduled to land on the comet on September 30and then shut down.

Philae spent just a few days transmitting data from the comet’s surface (SN: 8/22/15, p. 13). It had a rough landing, bouncing twice before stopping. Sitting in the shadow of a cliff, Philae was unable to use solar power to recharge its battery. Rosetta picked up intermittent communication in June and July 2015. Since January, temperatures on the comet have been too chilly for Philae’s electronics; scientists stopped listening for radio signals in July.

Sea ice around the North Pole has reached its second-lowest low on record, tying with 2007, scientists at NASA and the National Snow and Ice Data Center announced September 15.

Arctic sea ice reached its expected low point for the year on September 10, bottoming out at an area of 4.14 million square kilometers. That’s well below the 1981 through 2010 average of 6.22 million square kilometers, though above the record-lowest extent of 3.39 million square kilometers, set in 2012.

The silver-medal finish came after a summer of relatively cool temperatures, cloudy skies and stormy weather — conditions that typically limit sea ice shrinkage. The lack of ice probably arose from a poor starting position: The melt season began with the smallest maximum sea ice extent on record.

Shrinking sea ice can speed up warming, threaten Arctic species and spread pollution.