Fingerprints give away more than identity

The one-of-a-kind pattern of ridges and valleys in a fingerprint may not only betray who was present at a crime scene. It may also tattle about what outlawed drugs a suspect handled.

With advanced spectroscopy, researchers can detect and measure tiny flecks of cocaine, methamphetamine and heroin — in some cases as little as trillionths of a gram — on a lone fingerprint. The study, led by researchers at the National Institute of Standards and Technology in Gaithersburg, Md., appears May 7 in Analytical Chemistry.
Using an ink-jet–printed array of known quantities of drugs, researchers calibrated their spectroscopy techniques to measure specks of the chemicals. Then, using a 3-D printed plastic finger and a synthetic version of finger oil, researchers created drug-tainted fingerprints pressed onto paper or silicon.

On paper, the researchers detected as little as 1 nanogram of cocaine and amounts above 50 nanograms of methamphetamine and heroin. On silicon, the method picked up as little as 8 picograms of cocaine and heroin and around 1 nanogram of methamphetamine.

Researchers could also point to the location of the drugs on the fingerprint— at the peaks or dips of the pattern, for instance. Such information, the authors say, could help investigators finger what chemicals a suspect handled first and help corroborate a timeline of events in a crime.

Animal moms sacrifice a lot — sometimes even themselves

In the animal world, just like the human one, sometimes it’s not easy being mom. Fellow blogger Laura Sanders will tell you all about the trials and tribulations of being a mother to Homo sapiens. But some moms of the animal kingdom make sacrifices that go far beyond carrying a baby for nine months or paying for college.

Binge-eating sea otters
Adult female sea otters spend six months out of every year nursing at least one pup, sometimes two. Feeding herself isn’t easy — she’s got to eat the equivalent of 20 to 25 percent of her body mass every day to survive. But that amount has to increase while she’s nursing. By the time a pup is weaned at six months old, mom has to nearly double her food intake, researchers reported last year in the Journal of Experimental Biology. And to make matters worse, sometimes her kid will steal her food.
Single, starving mom
About two months before giving birth, a polar bear will enter her maternity den, remaining there for four to eight months. She stays holed up for that entire time, never eating, never drinking. Her cubs, only about half a kilogram at birth, grow quickly feeding on mom’s rich milk. And once they’re big enough to venture out, mama bear leads her babies straight to the sea so she can finally catch herself a meal.

Walled in by poo
Various species of Asian hornbills all share a similar nesting strategy: To protect her eggs from predators, mom walls herself up in a tree with a combination of mud, feces and regurgitated fruit. She leaves one tiny hole, through which dad feeds her for up to four months when mother and children are finally ready to emerge.

Endless sleepless nights
Human babies are known for their ability to rouse mom with their cries and prevent her from getting much sleep. But orca and dolphin moms don’t sleep at all for a month or more after they give birth. Unlike human babies that need a lot of sleep, tiny orcas and dolphins don’t sleep in the weeks after they’re born. That means no sleep for mom.

It’s mom for dinner
There’s a hint in the name of a limbless amphibian called Microcaecilia dermatophaga — young caecilians eat the skin of their mother, researchers reported in 2013 in PLOS ONE. But in a recent issue of Science News, Susan Milius highlighted an even more disgusting case of mom serving herself up for her kids: A female Stegodyphus lineatus spider feeds her young on a regurgitated slurry made up of the last meals she’ll ever eat — and her own guts. Milius writes:

“As liquid wells out on mom’s face, spiderlings jostle for position, swarming over her head like a face mask of caramel-colored beads. This will be her sole brood of hatchlings, and she regurgitates 41 percent of her body mass to feed her spiderlings.”

The next time your mom talks about how much she sacrificed for you, say thanks, but remember, at least you didn’t eat her stomach.

Children’s cells live on in mothers

Mother’s Day is on my mind, and I’ve been thinking about the ways I’m connected to my mom and my two little daughters. Every so often I see flickers of my mom in my girls — they share the lines around their smiles and a mutual adoration of wildflowers. Of course, I’m biased. I know that I’m seeing what I’m looking for. But biologically speaking, mothers and their children are connected in a way that may surprise you.

Way back when you and your mom shared a body, your cells mingled. Her cells slipped into your body and your cells circled back into her. This process, called fetal-maternal microchimerism, turns both mother and child into chimeras harboring little pieces of each other.

Cells from my daughters are knitted into my body and bones and brain. I also carry cells from my mom, and quite possibly from my grandma. I may even harbor cells from my older brother, who may have given some cells to my mom, who then gave them to me. It means my younger brother just might have cells from all of us, poor guy. This boundary blurring invites some serious existential wonder, not least of which might involve you wondering if this means your family members really are in your head.

These cellular threads tie families together in ways that scientists are just starting to discover. Here are a few of my favorite instances of how cells from a child have woven themselves into a mother’s body:
Fetal cells are probably sprinkled throughout a mother’s brain. A study of women who had died in their 70s found that over half of the women had male DNA (a snippet from the Y chromosome) in their brains, presumably from when their sons were in the womb. Scientists often look for male DNA in women because it’s easier than distinguishing a daughter’s DNA from her mother’s. If DNA from daughters were included, the number of women with children’s cells in their brains would probably be even higher.

When the heart is injured, fetal cells seem to flock to the site of injury and turn into several different types of specialized heart cells. Some of these cells may even start beating, a mouse study found. So technically, those icky-sweet Mother’s Day cards may be right: A mother really does hold her children in her heart.

Fetal cells circulate in a mother’s blood. Male DNA turned up in blood samples from women who were potential stem cell donors. That result may have implications for stem cell transplants. This cell swapping may make parents better donor candidates for their children than strangers, for instance.
Other studies have found fetal cells in a mother’s bones, liver, lungs and other organs, suggesting that these cells have made homes for themselves throughout a mother’s body. Maybe this is a way for a child to give back to the mother, in a sense. Growing fetuses slurp nutrients and energy out of a mother’s body during pregnancy (not to mention the morning sickness, heartburn and body aches). In return, fetuses offer up these young, potentially helpful cells. Perhaps these fetal cells, which may possess the ability to turn into lots of different kinds of cells, can help repair a damaged heart, liver or thyroid, as some studies have hinted.

Before I get carried away, a caveat: these cells may also make mischief. They may have a role in autoimmune disorders, for instance.

Microchimerism also has implications here for women who have lost pregnancies, an extremely common situation hidden by the taboo of talking about miscarriages. Fetal cells seem to migrate early in pregnancy, meaning that even brief pregnancies may leave a cellular mark on a woman.

Scientists are just starting to discover how this cellular heritage works, and how it might influence health. The scientist in me can’t wait to see how this story unfolds. But for now, I’m content to marvel at the mother and daughters in me.

Stimulating nerve cells stretches time between thinking, doing

A zap to the head can stretch the time between intention and action, a new study finds. The results help illuminate how intentions arise in the brain.

The study, published in the May 6 Journal of Neuroscience, “provides fascinating new clues” about the process of internal decision making, says neuroscientist Gabriel Kreiman of Harvard University. These sorts of studies are bringing scientists closer to “probing some of the fundamental questions about who we are and why we do what we do,” he says.
Figuring out how the brain generates a sense of control may also have implications for people who lack those feelings. People with alien hand syndrome, psychogenic movement disorders and schizophrenia can experience a troubling disconnect between intention and action, says study coauthor Biyu Jade He of the National Institutes of Health in Bethesda, Md.

In the study, the researchers manipulated people’s intentions without changing their actions. The researchers told participants to click a mouse whenever the urge struck. Participants estimated when their intention to click first arose by monitoring a dot’s position on a clockface.

Intention to click usually preceded the action by 188 milliseconds on average, the team found. But a session of transcranial direct current stimulation, or tDCS, moved the realization of intention even earlier, stretching time out between awareness of intention and the action. tDCS electrodes delivered a mild electrical zap to participants’ heads, dialing up the activity of carefully targeted nerve cells. After stimulation, intentions arrived about 60 to 70 milliseconds sooner than usual. tDCS seemed to change certain kinds of brain activity that may have influenced the time shift, EEG recordings suggested.

The results highlight how thoughts and intentions can be separated from the action itself, a situation that appears to raise thorny questions about free will. But these tDCS zaps didn’t change the action outcome or participants’ feelings of control, only the reported timing of a person’s conscious intention.

Scientists take first picture of thunder

MONTREAL — For the first time, scientists have precisely captured a map of the boisterous bang radiating from a lightning strike. The work could reveal the energies involved in powering some of nature’s flashiest light shows.

As electric current rapidly flows from a negatively charged cloud to the ground below, the lightning rapidly heats and expands the surrounding air, generating sonic shock waves. While scientists have a basic understanding of thunder’s origins, they lack a detailed picture of the physics powering the crashes and rumbles.
Heliophysicist Maher Dayeh of the Southwest Research Institute in San Antonio and colleagues sparked their own lightning by firing a long, Kevlar-coated copper wire into an electrically charged cloud using a small rocket. The resulting lightning followed the conductive wire to the ground. Using 15 sensitive microphones laid out 95 meters from the strike zone, Dayeh said he and his colleagues precisely recorded the incoming sound waves. Because sound waves from higher elevations took longer to reach the microphones, the scientists could create an acoustic map of the lightning strike with “surprising detail,” Dayeh said. He presented the results May 5 at a meeting of the American Geophysical Union and other organizations.

The loudness of a thunderclap depends on the peak electric current flowing through the lightning, the researchers found. This discovery could one day allow scientists to use thunder to sound out the amount of energy powering a lightning strike, Dayeh said.
SHOCK AND AWE Scientists shot a long copper wire into a lightning-prone cloud using a small rocket. The generated lightning followed the wire down to the ground, allowing the researchers to record the sound waves of the resulting thunder. The green flashes are caused by the intense heating of the copper wire. Credit: Univ. of Florida, Florida Institute of Technology, SRI

This octopus-inspired glove helps humans grip slippery objects

A new high-tech glove totally sucks — and that’s a good thing.

Each fingertip is outfitted with a sucker inspired by those on octopus arms. These suckers allow people to grab slippery, underwater objects without squeezing too tightly, researchers report July 13 in Science Advances.

“Being able to grasp things underwater could be good for search and rescue, it could be good for archaeology, [and] could be good for marine biology,” says mechanical engineer Michael Bartlett of Virginia Tech in Blacksburg.
Each sucker on the glove is a raspberry-sized rubber cone capped with a thin, stretchy rubber sheet. Vacuuming the air out of a sucker pulls its cap into a concave shape that sticks to surfaces like a suction cup. Pumping air back into the sucker inflates its cap, causing it to pop off surfaces. Each finger is also equipped with a Tic Tac–sized sensor that detects nearby surfaces. When the sensor comes within some preset distance of any object, it switches the sucker on that finger to sticky mode.

Bartlett and colleagues used the glove to pick up objects underwater, including a toy car, plastic spoon and metal bowl. Each sucker could lift about one kilogram in open air — and could lift more underwater, with the help of buoyancy, Bartlett says. Adding more suckers could give the glove an even stronger grip.
The octopus-inspired glove barely brushes the surface of what octopuses and other cephalopods can do. Octopuses can individually control thousands of suckers across their eight arms to feel around the seafloor and snatch prey. The suckers do this using not only tactile sensors, but also chemical-detecting cells that “taste” their surroundings (SN: 10/29/20).

The new glove is far from turning fingers into extra tongues. But Bartlett is intrigued by the possibility of adding chemical sensors so that the suckers stick to only certain materials.

In the battle of human vs. water, ‘Water Always Wins’

Humans have long tried to wrangle water. We’ve straightened once-meandering rivers for shipping purposes. We’ve constructed levees along rivers and lakes to protect people from flooding. We’ve erected entire cities on drained and filled-in wetlands. We’ve built dams on rivers to hoard water for later use.

“Water seems malleable, cooperative, willing to flow where we direct it,” environmental journalist Erica Gies writes in Water Always Wins. But it’s not, she argues.

Levees, which narrow channels causing water to flow higher and faster, nearly always break. Cities on former wetlands flood regularly — often catastrophically. Dams starve downstream environs of sediment needed to protect coastal areas against rising seas. Straightened streams flow faster than meandering ones, scouring away riverbed ecosystems and giving water less time to seep downward and replenish groundwater supplies.

In addition to laying out this damage done by supposed water control, Gies takes readers on a hopeful global tour of solutions to these woes. Along the way, she introduces “water detectives”— scientists, engineers, urban planners and many others who, instead of trying to control water, ask: What does water want?
These water detectives have found ways to give the slippery substance the time and space it needs to trickle underground. Around Seattle’s Thornton Creek, for instance, reclaimed land now allows for regular flooding, which has rejuvenated depleted riverbed habitat and created an urban oasis. In California’s Central Valley, scientists want to find ways to shunt unpolluted stormwater into ancient, sediment-filled subsurface canyons that make ideal aquifers. Feeding groundwater supplies will in turn nourish rivers from below, helping to maintain water levels and ecosystems.

While some people are exploring new ways to manage water, others are leaning on ancestral knowledge. Without the use of hydrologic mapping tools, Indigenous peoples of the Andes have a detailed understanding of the plumbing that links surface waters with underground storage. Researchers in Peru are now studying Indigenous methods of water storage, which don’t require dams, in hopes of ensuring a steady flow of water to Lima — Peru’s populous capital that’s periodically afflicted by water scarcity. These studies may help convince those steeped in concrete-centric solutions to try something new. “Decision makers come from a culture of concrete,” Gies writes, in which dams, pipes and desalination plants are standard.

Understanding how to work with, not against, water will help humankind weather this age of drought and deluge that’s being exacerbated by climate change. Controlling water, Gies convincingly argues, is an illusion. Instead, we must learn to live within our water means because water will undoubtedly win.

Do gophers farm roots? It’s not as clear as viral articles claim

Pocket gophers certainly don’t qualify as card-carrying 4-H members, but the rodents might be farming roots in the open air of their moist, nutrient-rich tunnels.

The gophers subsist mostly on roots encountered in the tunnels that the rodents excavate. But the local terrain doesn’t always provide enough roots to sustain gophers, two researchers report in the July 11 Current Biology. To make up the deficit, the gophers practice a simple type of agriculture by creating conditions that promote more root growth, suggest ecologist Jack Putz of the University of Florida in Gainesville and his former zoology undergraduate student Veronica Selden.
But some scientists think it’s a stretch to call the rodents’ activity farming. Gophers aren’t actively working the soil, these researchers say, but inadvertently altering the environment as the rodents eat and poop their way around — much like all animals do.

Tunnel digging takes a lot of energy — up to 3,400 times as much as walking along the surface for gophers. To see how the critters were getting all this energy, Selden and Putz in 2021 began investigating the tunnels of southeastern pocket gophers (Geomys pinetis) in an area being restored to longleaf pine savanna in Florida that Putz partially owns.

The pair took root samples from soil adjacent to 12 gopher tunnels and extrapolated how much root mass a gopher would encounter as it excavated a meter of tunnel. Then the researchers calculated the amount of energy that those roots would provide.

“We were able to compare energy cost versus gain, and found that on average there is a deficit, with about half the cost of digging being unaccounted for,” Selden says.

Upon examining some tunnels, Selden and Putz saw gopher feces spread through the interior along with signs of little bites taken out of roots and churning of the soil.

The gophers, the researchers conclude, provide conditions that favor root growth by spreading their own waste as fertilizer, aerating the soil and repeatedly nibbling on roots to encourage new sprouting.

“All of these activities encourage root growth, and once the roots grow into the tunnels, the gophers crop the roots,” Selden says. She and Putz say that this amounts to a rudimentary form of farming. If so, gophers would be the first nonhuman mammals to be recognized as farmers, Putz says. Other organisms, such as some insects, also farm food and started doing so much earlier than humans (SN: 4/23/20).

But the study has its skeptics. “I don’t really think you can call it farming per the human definition. All herbivores eat plants, and everybody poops,” says J.T. Pynne, a wildlife biologist at the Georgia Wildlife Federation in Covington who studies southeastern pocket gophers. So the root nibbling and tunnel feces might not be signs of agriculture, just gophers doing what all animals do.

Evolutionary biologist Ulrich Mueller agrees. “If we accept the tenuous evidence presented in the Selden article as evidence for farming … then most mammals and most birds are farmers because each of them accidentally have also some beneficial effects on some plants that these mammals or birds also feed on,” he says.

Not only that, but the study is also dangerous, says Mueller, of the University of Texas at Austin. The public will see through “the shallowness of the data,” he says, and will conclude that science is “just a bunch of storytelling, eroding general trust in science.”

For her part, Selden says she understands that because gophers don’t plant their crops, not everyone is comfortable calling them farmers. Still, she argues that “what qualifies the gophers as farmers and sets them apart from, say, cattle, which incidentally fertilize the grass they eat with their wastes, is that gophers cultivate and maintain this ideal environment for roots to grow into.”

At the very least, Putz says, he hopes their research makes people kinder toward the rodents. “If you go to the web and put in ‘pocket gopher,’ you’ll see more ways to kill them than you can count.”

50 years ago, a new theory of Earth’s core began solidifying

In the beginning, scientists believe there was an interstellar gas cloud of all the elements comprising the Earth. A billion or so years later, the Earth was a globe of concentric spheres with a solid iron inner core, a liquid iron outer core and a liquid silicate mantle…. The current theory is that the primeval cloud’s materials accreted … and that sometime after accretion, the iron, melted by radioactive heating, sank toward the center of the globe…. Now another concept is gaining ground: that the Earth may have accreted … with core formation and accretion occurring simultaneously.

Update
Most scientists now agree that the core formed as materials that make up Earth collided and glommed together and that the process was driven by heat from the smashups. The planet’s heart is primarily made of iron, nickel and some oxygen, but what other elements may dwell there and in what forms remains an open question. Recently, scientists proposed the inner core could be superionic, with liquid hydrogen flowing through an iron and silicon lattice (SN: 3/12/22, p. 12).

A new look at the ‘mineral kingdom’ may transform how we search for life

If every mineral tells a story, then geologists now have their equivalent of The Arabian Nights.

For the first time, scientists have cataloged every different way that every known mineral can form and put all of that information in one place. This collection of mineral origin stories hints that Earth could have harbored life earlier than previously thought, quantifies the importance of water as the most transformative ingredient in geology, and may change how researchers look for signs of life and water on other planets.
“This is just going to be an explosion,” says Robert Hazen, a mineralogist and astrobiologist at the Carnegie Institution for Science in Washington, D.C. “You can ask a thousand questions now that we couldn’t have answered before.”

For over 100 years, scientists have defined minerals in terms of “what,” focusing on their structure and chemical makeup. But that can make for an incomplete picture. For example, though all diamonds are a kind of crystalline carbon, three different diamonds might tell three different stories, Hazen says. One could have formed 5 billion years ago in a distant star, another may have been born in a meteorite impact, and a third could have been baked deep below the Earth’s crust.
So Hazen and his colleagues set out to define a different approach to mineral classification. This new angle focuses on the “how” by thinking about minerals as things that evolve out of the history of life, Earth and the solar system, he and his team report July 1 in a pair of studies in American Mineralogist. The researchers defined 57 main ways that the “mineral kingdom” forms, with options ranging from condensation out of the space between stars to formation in the excrement of bats.

The information in the catalog isn’t new, but it was previously scattered throughout thousands of scientific papers. The “audacity” of their work, Hazen says, was to go through and compile it all together for the more than 5,600 known types of minerals. That makes the catalog a one-stop shop for those who want to use minerals to understand the past.

The compilation also allowed the team to take a step back and think about mineral evolution from a broader perspective. Patterns immediately popped out. One of the new studies shows that over half of all known mineral kinds form in ways that ought to have been possible on the newborn Earth. The implication: Of all the geologic environments that scientists have considered as potential crucibles for the beginning of life on Earth, most could have existed as early as 4.3 billion years ago (SN: 9/24/20). Life, therefore, may have formed almost as soon as Earth did, or at the very least, had more time to arise than scientists have thought. Rocks with traces of life date to only 3.4 billion years ago (SN: 7/26/21).

“That would be a very, very profound implication — that the potential for life is baked in at the very beginning of a planet,” says Zachary Adam, a paleobiologist at the University of Wisconsin–Madison who was not involved in the new studies.

The exact timing of when conditions ripe for life arose is based on “iffy” models, though, says Frances Westall, a geobiologist at the Center for Molecular Biophysics in Orléans, France, who was also not part of Hazen’s team. She thinks that scientists need more data before they can be sure. But, she says, “the principle is fantastic.”

The new results also show how essential water has been to making most of the minerals on Earth. Roughly 80 percent of known mineral types need H2O to form, the team reports.

“Water is just incredibly important,” Hazen says, adding that the estimate is conservative. “It may be closer to 90 percent.”
Taken one way, this means that if researchers see water on a planet like Mars, they can guess that it has a rich mineral ecosystem (SN: 3/16/21). But flipping this idea may be more useful: Scientists could identify what minerals are on the Red Planet and then use the new catalog to work backward and figure out what its environment was like in the past. A group of minerals, for example, might be explainable only if there had been water, or even life.

Right now, scientists do this sort of detective work on just a few minerals at a time (SN: 5/11/20). But if researchers want to make the most of the samples collected on other planets, something more comprehensive is needed, Adam says, like the new study’s framework.

And that’s just the beginning. “The value of this [catalog] is that it’s ongoing and potentially multigenerational,” Adam says. “We can go back to it again and again and again for different kinds of questions.”

“I think we have a lot more we can do,” agrees Shaunna Morrison, a mineralogist at the Carnegie Institution and coauthor of the new studies. “We’re just scratching the surface.”