NEW ORLEANS — Ever since Ötzi’s mummified body was found in the Italian Alps in 1991, researchers have been trying to pin down how the 5,300-year-old Tyrolean Iceman died. It now looks like this Copper Age hunter-gatherer simply froze to death, perhaps after suffering minor blood loss from an arrow wound to his left shoulder, anthropologist Frank Rühli of the University of Zurich reported April 20 at the annual meeting of the American Association of Physical Anthropologists.
“Freezing to death is quite likely the main cause of death in this classic cold case,” Rühli said. Ötzi succumbed to exposure within anywhere from a few minutes to a few hours, he estimated.
New analyses of the Iceman’s body, based on X-rays and CT scans, argue against the idea that Ötzi died from a stone arrowhead shot into his shoulder (SN: 9/6/14, p. 6). Surprisingly shallow penetration of that weapon into Ötzi’s shoulder ruptured a blood vessel but caused no major tissue damage, Rühli said. Internal bleeding totaled only about 100 milliliters, or a half cup, he and his colleagues concluded. That’s enough of a poke to cause plenty of discomfort but not death, Rühli said.
Several depressions and fractures on the Iceman’s skull also couldn’t have proven fatal, he added. Some researchers regard those injuries as signs that Ötzi was clubbed to death. Rühli’s team found that those skull injuries are more consistent with the ancient man having accidentally fallen and hit his head while walking over rough ground. The Iceman was found with fur headgear that probably helped to protect his noggin when he took a headlong tumble, Rühli suggested.
The enzyme that turns on the light for a glow-in-the-dark mushroom seems “promiscuous.” But in a good way.
Researchers have worked out new details of how two Neonothopanus fungi shine softly green at night. The team had earlier figured out that the basic starting material for bioluminescence in these fungi is a compound called hispidin, found in some other fungi as well as plants such as horsetails. Those plants don’t spontaneously give off light, but in the two Neonothopanus mushroom species, an enzyme rejiggers a form of hispidin into a compound that glows.
The enzyme that turns a fungus into a natural night-light isn’t that fussy as enzymes go, says Cassius V. Stevani of the University of São Paulo in Brazil. He and colleagues can tweak the compound that the enzyme normally reacts with and still get a glow, the researchers report April 26 in Science Advances.
This easygoing chemistry has allowed the team to develop blue to orange glows instead of just the natural yellowish-green. These bonus colors might mark the beginnings of a new labeling tool for molecular biologists, the researchers say.
By 1973, just nine years after the start of an antimosquito campaign, the Aedes aegypti will be eradicated from the United States. The mosquito, a potential carrier of yellow fever, dengue and hemorrhagic fever, has been the target of a $23 million attack launched in 1964…. The carrier of these viral diseases can still be found in 10 southern states, Hawaii, the Virgin Islands and Puerto Rico. — Science News, May 20, 1967
Update The eradication program, which used chemical sprays and eliminated breeding sites, never came close to getting rid of A. aegypti. Today, the virus-carrying insect’s potential range includes more than 20 states and other U.S. territories. And some carrying the Zika virus have been found in the continental United States. Researchers are investigating new ways to conquer A. aegypti, by inserting faulty genes into its DNA or dosing it with a sterilizing bacterium (SN: 4/1/17, p. 10).
The Bro Code apparently does not exist among wild cuttlefish. The first field video of male European cuttlefish (Sepia officinalis) getting physical over a female shows that they are not above stealing another guy’s girl.
Cuttlefish, cephalopods known for their ability to alter their skin color, have complex and competitive courtship rituals. While scientists have extensively studied common European cuttlefish fights over mates, observing such altercations has proven elusive outside of the lab. In 2011, biologists Justine Allen of Brown University in Providence, R.I., and Derya Akkaynak of the University of Haifa in Israel lucked out. They were in the Aegean Sea off the coast of Turkey following a female cuttlefish with an underwater camera to study camouflage, when a male cuttlefish approached the female, and the pair mated. Soon after, another male appeared on the scene and edged in on the female. A battle of ink and arms ensued. “I just remember there being a lot of ink everywhere — so much ink,” Allen recalls. It took the original male three tries to reclaim his mate, the team writes in the July issue of The American Naturalist. Each attempt escalated in intensity. That’s consistent with a game theory model where opponents assess peers’ abilities as well as their own, the scientists suggest. The footage confirms that males in the wild use an arsenal of aggressive behaviors to oust romantic rivals — tactics like darkening the skin around their eyes and face, displaying a zebra pattern on their body, spraying ink while jetting through the water, biting and wrestling. Lab bouts pale in comparison to the viciousness of this encounter.
Determining whether any of this is typical for fights between males of this species requires more data and more cuttlefish.
Health care quality and availability improved globally from 1990 to 2015, but the gap between the haves and the have-nots widened in those 25 years, researchers report online May 18 in the Lancet.
As an approximate measure of citizens’ access to quality health care, an international team of researchers analyzed mortality rates for 32 diseases and injuries that are typically not fatal when effective medical care is available. The team summarized this data as a number on a scale from zero to 100, called the Healthcare Access and Quality Index, for 195 countries and territories. Places with the highest scores in 2015 include Canada, Australia, Japan and much of Europe, while some African countries as well as India, Pakistan, Afghanistan and Papua New Guinea have the lowest scores. The countries with the greatest improvement since 1990 include South Korea, Peru and China.
The growing gap between countries with the highest and lowest scores suggests that health care inequalities due to geography may be on the rise, the authors say.
Pancreatic cancer is hard to detect early, when the disease is most amenable to treatment. But a new study describes a blood test that may aid the diagnosis of pancreatic cancer and someday make earlier screening feasible, the authors say.
The test detects a combination of five tumor proteins that appear to be a reliable signature of the disease, the researchers report in the May 24 Science Translational Medicine. In patients undergoing pancreatic or abdominal surgery, the test was 84 percent accurate at picking out those who had pancreatic cancer. “What’s exciting about the study is that it further favors the belief that one biomarker by itself may not be able to successfully identify a disease,” says Raghu Kalluri, a cancer biologist at the University of Texas MD Anderson Cancer Center in Houston who was not involved in the study. By putting the five protein biomarkers together, he says, “the power of the analysis might be more beneficial in differentiating healthy individuals and ones with pancreatic cancer.”
The National Cancer Institute estimates that in 2017 there will be more than 53,000 new cases of pancreatic cancer in the United States and just over 43,000 deaths from the cancer. Individuals with the most common form of pancreatic cancer, called pancreatic ductal adenocarcinoma, have a five-year survival rate of less than 10 percent. The cancer is usually caught late because the symptoms, including weight loss and abdominal pain, often don’t arise until the cancer has spread. And current imaging technology can’t detect the cancer at the start, says study coauthor Cesar Castro, a translational oncologist at Massachusetts General Hospital in Boston.
“The unmet need here is finding some other form of detection before a cancer grows large enough for the CT scan to detect it,” Castro says.
In their hunt for better detection methods, the researchers turned to tumor-derived extracellular vesicles, small sacs shed by tumor cells that circulate in the bloodstream. The sacs “are almost like mini-mes” of the parent tumor, Castro says, because they contain proteins and genetic material that often match the tumor.
The researchers selected five promising protein biomarkers from tumor-derived extracellular vesicles. Using a gold-coated silicon chip covered with antibodies and sporting nanopores, the team tested how well the biomarkers signaled the presence of pancreatic cancer in plasma samples from patients. When light shining through the pores encountered the extracellular vesicles, bound to the chip because of the interaction between the protein biomarkers and the antibodies, the light’s wavelength changed — signaling the presence of a tumor. In plasma samples taken from 43 patients before scheduled surgery for a medical issue in the pancreas or abdomen, the panel of five biomarkers distinguished pancreatic ductal adenocarcinoma from pancreatitis — an inflammation of the pancreas — and from benign cysts as well as from control patients’ samples. A pathology report after the surgeries confirmed the results.
Using their sensing device, the researchers report that the combined five biomarkers correctly identified whether a patient had pancreatic ductal adenocarcinoma or not in 84 percent of cases. The highest accuracy for any one of these biomarkers used by itself was just 70 percent.
The next step is to test patients at high risk for pancreatic cancer, and eventually those who are healthy, to see if these biomarkers are effective at early screening. “What we need to do now is pivot towards precancerous lesions,” Castro says. “Can they pick up any precancerous changes?”
“I’m excited about anything that can happen for these patients who are in desperate need for biomarkers and treatment,” Kalluri says. But he cautions that studies reporting the effectiveness of biomarkers as cancer screening tools often use different technologies for their assessments, making it hard for academic laboratories to reproduce the results. “There’s a tremendous lack of organized effort in the biomarker field,” he says, and if there is no way to come to a consensus on which biomarkers are most promising, “it’s very difficult for a patient to realize any benefit.”
Some of the earliest settlers of the Americas curtailed their coastal migration to hunker down in what’s now northwestern Peru, new finds suggest. Although researchers have often assumed that shoreline colonizers of the New World kept heading south from Alaska in search of marine foods, staying put in some spots made sense: Hunter-gatherers needed only simple tools to exploit rich coastal and inland food sources for thousands of years.
Excavations at two seaside sites in Peru find that people intermittently camped there from about 15,000 to 8,000 years ago, say anthropologist Tom Dillehay of Vanderbilt University in Nashville and his colleagues. Ancient people along Peru’s Pacific coast didn’t leave behind fishhooks, harpoons, nets or boats that could have been used to capture fish, sharks and sea lions, the scientists report May 24 in Science Advances. Yet remains of those sea creatures turned up at coastal campsites now buried beneath a human-made, earthen mound called Huaca Prieta and an adjacent mound called Paredones. Fish and other marine animals probably washed up on beaches or were trapped in lagoons that formed near the shore, Dillehay’s group proposes. Hungry humans needed only nets or clubs to subdue these prey. Other marine foods found at the ancient Peruvian campsites included snails, crabs, clams, sea gulls and pelicans. Fragments of material woven out of rush plants, the earliest dating to between 10,600 and 11,159 years ago, may have come from fish traps or baskets, the researchers say. Radiocarbon dating of burned wood, animal bones and plant seeds provided age estimates for a series of buried campsites at Huaca Prieta and Paredones.
Present-day hunters on Peru’s coast eat fish and small sharks that get trapped on the beach or in shallow shoreline lagoons. Hunters also build blinds where they wait to net and club birds, a tactic probably also used by ancient Americans, the investigators suspect.
Deer bones indicate that ancient Huaca Prieta and Paredones visitors hunted on land as well. And remains of avocado, beans and possibly cultivated squash and chili peppers at the ancient campsites — foods known to have been gathered or grown at inland locations — suggest that people transported these foods to the coast, possibly via trading. Evidence that early New World settlers trekked back and forth from coastal to interior parts of Peru coincides with similar human movements in southern Chile more than 14,000 years ago (SN Online: 5/8/08). A team led by Dillehay uncovered seaweed fragments in hearths and structures at Monte Verde II, located 30 kilometers from Chile’s coast. Edible rushes, reeds and stones from the coast also turned up at Monte Verde II.
“Just as there was some contact with the sea at Monte Verde II, there was some contact with the interior at Huaca Prieta,” Dillehay says.
Simple stone tools, sharpened on one side, dominate implements excavated at the Peruvian sites and at Monte Verde II. Basic tools suitable for all sorts of cutting and scraping tasks fit a lifestyle in which people sought food across varied landscapes, the researchers contend. Similar conditions may have characterized some North American coastlines by around 15,000 years ago, Dillehay says. “The problem is that these areas are now underwater” due to a global sea level rise between 20,000 and 6,000 years ago (SN: 8/13/11, p. 22).
Accumulating evidence supports the idea that early Americans favored the coast over an inland lifestyle, says archaeologist Daniel Sandweiss of the University of Maine in Orono. An ice-free corridor into North America’s interior may not have formed before 12,600 years ago (SN Online: 8/10/16), after people had reached Peru and Chile.
The pace at which people moved south from Huaca Prieta is unknown, Sandweiss says. Monte Verde II dates to roughly 500 years after the first coastal campsites in Peru, raising the possibility that Huaca Prieta folk founded the Chilean site, he suggests.
Dillehay doubts it. Modern hunter-gatherer groups vary greatly in size but usually don’t exceed several hundred members, making it unlikely that ancient Huaca Prieta and Paredones people were numerous enough to encounter food shortages, he says. Even if food ran out, hunter-gatherers only had to move a few kilometers north or south to find abundant grub. “We really don’t know where these people were coming and going,” Dillehay cautions.
If the Milky Way exists in the biggest cosmic void ever observed, that could solve a puzzling mismatch between ways to measure how fast the universe is expanding.
Observations of 120,000 galaxies bolstering the Milky Way’s loner status were presented by Benjamin Hoscheit June 7 at a meeting of the American Astronomical Society in Austin, Texas. Building on earlier work by his adviser, University of Wisconsin‒Madison astronomer Amy Barger, Hoscheit and Barger measured how the density of galaxies changed with distance from the Milky Way. In agreement with the earlier study, the pair found that the Milky Way has far fewer neighbors than it should. There was a rise in density about 1 billion light-years out, suggesting the Milky Way resides in an abyss about 2 billion light-years wide.
Simulations of how cosmic structures form suggest that most galaxies clump along dense filaments of dark matter, which are separated by vast cosmic voids.
If the Milky Way lives in such a void, it could help explain why the universe seems to be expanding at different rates depending on how it’s measured (SN: 8/6/16, p. 10). Measurements based on the cosmic microwave background, the earliest light in the universe, suggest one rate of expansion, while measurements of nearby supernovas suggest a faster one.
Those supernovas could be feeling an extra gravitational pull from all the matter at the edges of the void, Hoscheit says. The actual expansion rate is probably the slower one measured in the universe’s early light.
“If you don’t account for the void effects, you could mistake this relationship to indicate that there is too much expansion,” Hoscheit says.
Those who struggle to fit a vacation wardrobe into a carry-on might learn from ladybugs. The flying beetles neatly fold up their wings when they land, stashing the delicate appendages underneath their protective red and black forewings.
To learn how one species of ladybug (Coccinella septempunctata) achieves such efficient packing, scientists needed to see under the bug’s spotted exterior. So a team from Japan replaced part of a ladybug’s forewing with a transparent bit of resin, to get a first-of-its-kind glimpse of the folding. Slow-motion video of the altered ladybug showed that the insect makes a complex, origami-like series of folds to stash its wings, the scientists report in the May 30 Proceedings of the National Academy of Sciences. CT scans helped explain how the wings can be both strong enough to hold the insects aloft and easily foldable into a tiny package. The shape of the wing veins allows them to flex like a metal tape measure, making the wings stiff but bendable. Lessons learned from the wings could be applied to new technologies, including foldable aircraft wings or solar panels that unfurl from a spacecraft.
The hunt for gravitational waves is moving upward. A space-based detector called the Laser Interferometer Space Antenna, or LISA, was selected as a mission in the European Space Agency’s science program, the agency announced June 20.
LISA will consist of three identical satellites arranged in a triangle that will cartwheel through space in orbit around the sun just behind Earth. The spacecraft will use lasers to detect changes in the distance between each satellite. Those changes would indicate the passage of gravitational waves, the ripples in spacetime that massive bodies such as black holes shake off when they move.
The spacecraft was originally planned as a joint mission between ESA and NASA, but NASA pulled out in 2011 citing budget issues. In December 2015, ESA launched a single satellite called LISA Pathfinder to test the concept — a test it passed with flying colors.
Interest in LISA increased in 2016 after researchers at the ground-based LIGO detectors announced that they had finally observed gravitational waves. LIGO is best suited for detecting the crash caused when dense objects such as neutron stars or solar-mass black holes collide.
LISA, on the other hand, will be sensitive to the collision of much more massive objects — such as the supermassive black holes that make up most galaxies’ cores.
The mission design and cost are still being completed. If all goes as planned, LISA will launch in 2034.
