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.
Climate change may make the rich richer and the poor poorer in the United States.
Counties in the South face a higher risk of economic downturn due to climate change than their northern counterparts, a new computer simulation predicts. Because southern counties generally host poorer populations, the new findings, reported in the June 30 Science, suggest that climate change will worsen existing wealth disparities.
“It’s the most detailed and comprehensive study of the effects of climate change in the United States,” says Don Fullerton, an economist at the University of Illinois at Urbana-Champaign who was not involved in the work. “Nobody has ever even considered the effects of climate change on inequality.” Researchers created a computer program called SEAGLAS that combined several climate simulations to forecast U.S. climate until 2100, assuming greenhouse gas emissions keep ramping up. Then, using data from previous studies on how temperature and rainfall affect several economic factors — including crop yields, crime rates and energy expenditures — SEAGLAS predicted how the economy of each of the 3,143 counties in the United States would fare.
By the end of the century, some counties may see their gross domestic product decline by more than 20 percent, while others may actually experience more than a 10 percent increase in GDP. This could make for the biggest transfer of wealth in U.S. history, says study coauthor Solomon Hsiang, an economist at the University of California, Berkeley.
In general, SEAGLAS predicts that counties in the lower Midwest, the South and the Southwest — already home to some of the country’s poorest communities — will bear the brunt of climate-caused economic damages, while counties in New England, the Great Lakes region and the Pacific Northwest will suffer less or see gains. For many of the examined economic factors, such as the number of deaths per year, “getting a little bit hotter is much worse if you’re already very hot,” explains Hsiang. “Most of the south is the hottest part of the country, so those are the regions where costs tend to be really high.” The economic gaps may get stretched even wider than SEAGLAS predicts, Fullerton says, because the simulation doesn’t account for wealth disparities within counties. For example, wealthier people in poor counties may have access to air conditioning while their less fortunate neighbors do not. So blisteringly hot weather is most likely to harm the poorest of the poor.
Not all researchers, however, think the future is as bleak as SEAGLAS suggests. The simulation doesn’t fully account for adaptation to climate change, says Delavane Diaz, an energy and environmental policy analyst at the Electric Power Research Institute in Washington, D.C., a nonprofit research organization. For example, people in coastal regions could mitigate the cost of sea level rise by flood-proofing structures or moving inland, she says.
And the economic factors examined in this study don’t account for some societal benefits that may arise from climate change, says Derek Lemoine, an economist at the University of Arizona in Tucson. For instance, although crime rates rise when it’s warmer because more people tend to be out and about, people being active outside could have a positive impact on health.
But SEAGLAS is designed to incorporate different societal variables as new data become available. “I really like the system,” Lemoine says. “It’s a super ambitious work and the kind of thing that needs to be done.”
How well, not how much, people sleep may affect Alzheimer’s disease risk.
Healthy adults built up Alzheimer’s-associated proteins in their cerebral spinal fluid when prevented from getting slow-wave sleep, the deepest stage of sleep, researchers report July 10 in Brain. Just one night of deep-sleep disruption was enough to increase the amount of amyloid-beta, a protein that clumps into brain cell‒killing plaques in people with Alzheimer’s. People in the study who slept poorly for a week also had more of a protein called tau in their spinal fluid than they did when well rested. Tau snarls itself into tangles inside brain cells of people with the disease. These findings support a growing body of evidence that lack of Zs is linked to Alzheimer’s and other neurodegenerative diseases. Specifically, “this suggests that there’s something special about deep, slow-wave sleep,” says Kristine Yaffe, a neurologist and psychiatrist at the University of California, San Francisco who was not involved in the study.
People with Alzheimer’s are notoriously poor sleepers, but scientists aren’t sure if that is a cause or a consequence of the disease. Evidence from recent animal and human studies suggests the problem goes both ways, Yaffe says. Lack of sleep may make people more prone to brain disorders. And once a person has the disease, disruptions in the brain may make it hard to sleep. Still, it wasn’t clear why not getting enough shut-eye promotes Alzheimer’s disease. Researchers led by neurologist David Holtzman of Washington University School of Medicine in St. Louis speculated that lower levels of brain cell activity during deep sleep would produce less A-beta, tau and other proteins than other stages of sleep or wakefulness. Holtzman, Washington University sleep medicine physician Yo-El Ju and colleagues recruited 17 volunteers, all healthy adults between ages 35 and 65, who had no sleep disorders. “These are good sleepers,” Ju says. Volunteers wore activity monitors to track their sleep at home and visited the sleep lab at least twice. On one visit, the volunteers slept normally while wearing headphones. On the other visit, researchers played beeps through headphones whenever the volunteers were about to go into deep sleep. The sounds usually didn’t wake the people up but kept them from getting any slow-wave sleep. Volunteers slept just as much on the night when deep sleep was disrupted as they did on the night when no sound was played through the headphones. Spinal taps showed that the more deep sleep people missed out on, the higher their levels of A-beta in the morning. Tau levels didn’t budge because of just one night of slow-wave sleep disruption, but people whose activity monitors indicated they had slept poorly the week before the test also had higher levels of that protein.
“This study in humans is really an elegant experimental demonstration” that bolsters Holtzman’s hypothesis that lack of rest for brain cells could be detrimental, says Adam Spira, a psychologist at Johns Hopkins Bloomberg School of Public Health. Without proper deep sleep, brain cells continue to churn out, producing more A-beta and tau than a well-rested brain.
Some research has suggested that toxic proteins get flushed out of the brain during sleep (SN: 11/16/13, p. 7). Messing with slow-wave sleep doesn’t seem to interfere with this wash cycle, Ju says. Levels of other proteins made by nerve cells didn’t vary with the lack of deep sleep, she says.
